url stringlengths 14 1.76k | text stringlengths 100 1.02M | metadata stringlengths 1.06k 1.1k |
|---|---|---|
https://www.arxiv-vanity.com/papers/hep-th/0506042/ | arXiv Vanity renders academic papers from arXiv as responsive web pages so you don’t have to squint at a PDF. Read this paper on arXiv.org.
Preprint SB/F/05-330
On the Quantization of Massive Superparticles
N. Hatcher
Universidad Simón Bolívar, Departamento de Matemáticas, Apartado Postal 89000, Caracas 1080-A, Venezuela.
A. Restuccia and J. Stephany
Universidad Simón Bolívar, Departamento de Física, Apartado Postal 89000, Caracas 1080-A, Venezuela.
e-mail: , ,
Abstract
We consider the action of the supermembrane wrapping a compactified sector of the target space in such a way that a non trivial central charge in the SUSY algebra is induced. We show that the dynamics of the center of mass corresponds to a superparticle in with additional fermionic terms associated to the central charges . We perform the covariant quantization of this system following a direct approach which introduces an equivalent action for the system which has only first class constraints allowing to obtain the space of physical states in a covariant way. The resulting multiplet contains states corresponding to a ultrashort multiplet.
## 1 Introduction
The theory of the supermembrane [1] is a key element in the intricate network of related systems which are expected to define the consistent non perturbative aspects of quantum superstrings. It was originally constructed as the extended object which propagates consistently on a supergravity background but its role in -theory turn out to have more implications. It was shown in [2] that when the supermembrane is immersed in a Minkowski space its spectrum is continuous from but it is still unknown if there is a massless sector corresponding to the supergravity. It was also argued in Ref. [3] that the supermembrane on a compact target space should also have a continuous spectrum. In contrast the spectrum of the supermembrane wrapping a two cycle when the configuration space satisfies the topological condition which implies a non trivial central charge in the supersymmetric algebra, was shown to be a discrete set with finite multiplicity [4].
In this paper we focus in the low energy spectrum of the supermembrane wrapped on a two cycle by considering the covariant quantization of the associated superparticle. As we show below, the resulting action describes a massive superparticle with an additional spinorial term arising from the non trivial wrapping of the supermembrane on the two-cycle. In the massless case, as is well known, the covariant quantization of the Casalbuoni-Brink-Schwarz superparticle in [5] present similar obstacles related to the mixing of first and second class constraints associated with the -symmetry[6], as the Green-Schwarz superstring. The covariant gauge fixing of the symmetry was performed in [7, 8, 9] by introducing an infinite tower of auxiliary fields . More recently, a new formulation was advanced in terms of pure spinors which requires a finite number of fields[10]. The dynamics of a superparticle with a central charge was first considered in [11, 12] and later in [13]. However the central charges arose in these cases from considerations different to those presented here. The covariant quantization of this superparticle differs from the usual massive superparticle since the central charge implies the existence of a -symmetry additionally to the second class constraints already present for the massive superparticle. Several formulation to quantize the superparticle with central charges were proposed [13, 14, 15]. For example in [15] a charge was constructed also from a infinitely reducible set of first class constraints. Fortunately as we discuss in section 4 the structure of the system allows a direct approach in which the physical degrees of freedom are identified in a covariant way.
## 2 The Supermembrane in M9×Σ
The supermembrane action immersed in target space was obtained originally in Ref. [1] and is given by,
I=−18π2∫d3ξ[√−ggijπμiπjμ−√−g+iϵijkπμiπνj¯ψΓμν∂kψ] +[ϵijkπμi¯ψΓμν∂jψ¯ψΓν∂kψ−i3ϵijk¯ψΓμν∂iψ¯ψΓν∂jψψ¯ψΓν∂kψ] , (1)
where is a Majorana spinor and
πμi=∂iXμ−i¯ψΓμ∂iψ (2)
with the space time coordinate of the membrane. The supermembrane tension has been fixed to 1.
We are interested in the case when the target space has a compactified sector admitting a minimal immersion from the base manifold into it. is a Riemann surface of genus and corresponds to the range of the time variable .
To be specific let us consider the case in which is a torus and the compactified target space is [16, 4, 17], although more general compactified target spaces for which there exists a minimal immersion from into the target space may also be treated along the lines we follow here [18].
The minimal immersion is constructed from the harmonic one forms over denoted by , . We consider a pair of harmonic one-forms over satisfying
∮Csd^xr=2πmrs , r,s=1,2 (3)
where are integers and is a basis of the homology on , together with
∫Σd^xr∧d^xs=nA(Σ)≠0 , (4)
where and is the area of . The first condition implies that each may define a map over a circle . It also implies the equality in (4). The condition is the non trivial part of this relation.
The map from onto is given, with a fixed point in , by
P∈Σ→∫PP0d^xr mod (2πnr) , r=1,2 . (5)
Condition (4) implies that the algebra of the supermembrane has a non-trivial central charge with the number of times the supermembrane wraps . It may be shown that the above map is a local minimum of the hamiltonian of the supermembrane [19] and defines a minimal immersion from to [18]. It is a solution of the supermembrane field equations which preserves one half of the original supersymmetry. The most general configuration space and hamiltonian for the supermembrane with the above base manifold and target space with a non-trivial central charge was obtained in [4, 17, 16] and shown to have a discrete spectrum. We are interested here in the quantization of the corresponding superparticle with non-trivial central charges.
## 3 Compactification of the Supermembrane
We consider now the covariant quantization of the center of mass of the supermembrane which corresponds to a superparticle. To do so we restrict the configuration space by the following conditions,
Xm = Xm(τ) , m=0,…,8 (6) ψ = ψ(τ) , (7) Xr+8 = ^xr(σ) , r=1,2 (8)
where denote local coordinates over . On this class of configurations the supermembrane action reduces to
S→k∫dτ(e−1ωmωm−e−iψβ(12CΓrsϵrs)βγ˙ψγ) , ωm=˙Xm−i¯ψΓm˙ψ . (9)
where is the charge conjugation matrix in and is the antisymmetric product .(The conventions for the matrices are given in the appendix. is symmetric on the spinorial indices). The constant is given by .
In the following section we perform the covariant quantization of this system following a direct approach by introducing a new action for the superparticle with central charges with first class constraints only, that allows to obtain the space of physical states in a covariant way.
We use now a particular representation of the Dirac matrices. We consider the set of Dirac matrices in satisfying . We take as in [13],
Γm=[0iγm−iγm0] , Γ9=[0ii0] . (10)
Then we have , with
Γ11=Γ0Γ1…Γ9=[I00−I] . (11)
The charge conjugation matrix in in terms of the corresponding one in is (see the appendix)
C=[0−i~Ci~C0] , (12)
where and . Now we decompose the spinors in terms of the ones
ψ=(θ1θ2) . (13)
The Majorana condition in implies
¯θA=θTA~C , (14)
where . The action for the superparticle with central charges reduces then to
S=k∫dτ(e−1ωmωm−e−i¯θA˙θA) (15)
where now
ωm=˙Xm−i¯ωAγm˙ωA . (16)
## 4 The Hamiltonian for the Superparticle with central charges
Let us introduce here the mass parameter and the projectors,
P±=12m(m±γmpm) , (17)
which satisfy
P+P+ = −14m2(p2+m2)+P+ , P−P−=−14m2(p2+m2)+P− , P+P− = P−P+=14m2(p2+m2) , P++P−=I . (18)
The conjugate momenta to are
pm=2ke−1ωm , (19)
and the conjugate momenta to , with are
¯πA=2im¯θAP− (20)
or equivalently
πA=−2imP−θA . (21)
Introducing the Lagrange multiplier , the hamiltonian may then be expressed as
H=λ(p2+m2) (22)
subject to
πA+2imP−θA=0 , (23)
which are a mixture of first and second class constraints.
The set of constraints (23) together with the mass shell condition are equivalent to
p2+m2=0 , (24) P+πA=0 , (25) P−πA+2imP−θA=0 . (26)
Now (24) and (25) are first class constraints while (26) is a mixture of first and second class constraints.
We may then consider the set,
p2+m2=0 (27) φ1=P+(π1+iπ2)=0 (28) φ2=P+(π1−iπ2)=0 (29) Ω1=P−(π1+iπ2)+2imP−(θ1+iθ2)=0 (30) Ω2=P−(π1−iπ2)+2imP−(θ1−iθ2)=0 (31)
with the non trivial bracket,
{Ω1,Ω2}=−4imP− . (32)
We also note that the symplectic terms in the canonical action may be decomposed as
¯πA˙θA=12¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯(π1+iπ2)(˙θ1−i˙θ2)+12¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯(π1−iπ2)(˙θ1+i˙θ2) , (33)
and we identify the conjugate pairs , and ,. We notice here that the pair and may be regarded as a first class constraint () and an associate gauge fixing condition (). The contribution of this pair to the functional measure when taken as a pair of second class constraints or in the way proposed is exactly the same [20], [21]. With this observation we can finally define our system as a gauge system restricted by the set of first class constraints (27), (28) and (30). If one then would like to impose (31) as a partial gauge fixing condition the original set of constraints is recovered, but there is freedom to impose a different set of admissible gauge fixing conditions since the functional integral is invariant to this choice (In this case there are no gauge anomalies).
To continue we consider the partial gauge fixing conditions,
P+(θ1−iθ2)=0 , (34) P−(θ1−iθ2)=0 , (35)
corresponding to the symmetry generated by and respectively. This gauge fixing condition contributes to the functional integral with a constant factor independent of the fields. The canonical variables and may then be integrated out from the functional integral.
We are thus left with the canonical action,
L = p˙X+¯πA˙θA−H (36) = p˙X+12¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯(π1−iπ2)(˙θ1+i˙θ2) , (37)
constrained by (27) and (29). Let us introduce the variables and . Notice that is a complex spinor which does not satisfy the pseudo Majorana condition
We may finally consider the partial gauge fixing condition
P+(θ1+iθ2)=0, (38)
and perform a canonical reduction to
L=p˙X+¯¯¯¯¯¯¯¯¯¯¯¯¯¯(P−~π)(P−~θ) , (39)
subject to the mass shell condition (24). The space of physical states is obtained by considering superfields depending in and not on its complex conjugate. Since we have that without using the degrees of freedom in are exactly half of the ones in . They are therefore bosonic and fermionic on-shell degrees of freedom. It corresponds as we discuss below to a multiplet.
## 5 Conclusion
We have covariantly quantized the superparticle associated to the supermembrane wrapped on a torus with a non trivial central charge.
The Hilbert space of states we obtained is described in terms of an on-shell superfield . The spinorial variable has 8 independent variables. The superfield has degrees of freedom that fit neatly in a massive supermultiplet with central charge. The general form of this central charge in arising from the supermembrane algebra in is [23]
Zij=Zδij−(P9σ3−P10σ1) , (40)
with a BPS mass given by
M=√P29+P210+|Z| . (41)
In this paper we have taken . The multiplet that we have obtained from the quantization of the superparticle corresponds to a ultrashort KKB supermultiplet [23].
Due to the nature of our central charge we are studying the winding modes of the supermembrane on a torus and neglecting the Kaluza-Klein modes. As is well known [24] this states should correspond to the Kaluza-Klein modes of the IIB superstring wrapped on . Our results confirm this correspondence.
## 6 Acknowledgments
This work was supported by Did-Usb grants Gid-30 and Gid-11 and by Fonacit grant G-2001000712.
## Appendix A Appendix:Dirac matrices and Central charges
We collect here some useful results about the supersymmetry algebra in . We take the ”mostly plus” signature with the Dirac matrices satisfying . We construct these matrices recursively. Let be a set of Dirac matrices in dimensions ( even), then in dimensions we have,
Γμ=[0Sμ¯Sμ0] , S0=¯S0=ISi=γiγ0¯Si=−Si=ISD−1=γ0 . (42)
In an even dimensional space there exist matrices and such that
BΓμB−1=−(Γμ)∗~BΓμ~B−1=(Γμ)∗B=~BWCΓμC−1=−(Γμ)T~CΓμ~C−1=(Γμ)TC=~BΓ0 (43)
with . In odd dimensions there exist either or . There exist also a matrix in and a matrix in defined by,
~B9=γ0γ1γ3γ5γ7 , B11=Γ2Γ4Γ6Γ8 , (44)
such that
B11=[~B900−~B9] , C11=[0~C9γ0−~C9γ00] . (45)
To make contact with our notation of section 3, call that set of matrices they are related to by a unitary transformation
UΓμHU†=ΓμU=[i00γ0] . (46)
From here follows directly equation (12).
The most general supersymmetry algebra in and with Lorentz invariant central charges is
{Qai,Qbj}=2δijpμ(γμ~C−1)ab+Zij~Cab , (47)
with a real symmetric matrix. Note that we can write
γ0~C=[0JJ0],~C=[J00J],JT=J,J2=I . (48)
Since these two matrices commute they can be simultaneously diagonalized. Then the algebra in the rest frame takes the form
{Qai,Qbj}=2mδij[J00−J]+Zij[J00J] . (49)
The algebra of the 32 supercharges splits into 4, blocks. In our case and we find
{Qai,Qbj}=4mδij[J000] . (50)
The entire representation may be obtained now as usual. We notice that half of the supersymmetries are not present and the other half build a representation of states. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9682785272598267, "perplexity": 552.6076943247122}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-50/segments/1606141706569.64/warc/CC-MAIN-20201202083021-20201202113021-00342.warc.gz"} |
https://docs.zenotta.xyz/lightbook/the-zeno | Search…
The Zeno
A medium of exchange for digital assets
For a thing of value – an asset – to be traded, it needs a medium of exchange. In the blockchain space, the nature of ‘asset’ and ‘coin’ is often confused, since most cryptocurrencies treat coins as the assets themselves. With a real economy in the digital space, with distinct assets in the form of digital files, the coins become a medium that enables asset trade.
Implementing this approach avoids the paradox whereby the ‘token economics’ has no basis in the value of assets (and uses as a medium of exchange the ‘thing of value’ itself – the token (or coin) – creating something of a circular economic motivation). With proper blockchain governance of files and the cryptocurrency used as a medium of exchange, tokenomics can refer to the actual economics of a cryptocurrency; one that is used to pay for goods & services.
Zenotta’s tokenomic policy emphasises fairness and maximization of distribution, with long mining timelines (approx. 200 yrs), a large number of coins (10 billion) and a more inclusive mining algorithm (see Chapter 4). The desire or demand for assets rather than purely for coins creates a highly liquid market, and since the Zeno is the only currency traded for Smart Data, there is a strong incentive to use the currency rather than merely ‘hodl’ it. This increases distribution drastically over standard cryptocurrencies.
# Issuance schedule
Zeno issuance follows a fixed supply cap mechanic according to the properties outlined in the following table:
The total number of Zeno coins reached will be 10 billion, with 2.5 billion reserved for a treasury, to be used for stakeholders, a development fund, and an economic activity fund. The remaining 7.5 billion is mined out via a smoothed issuance curve based on the emission approach employed by the CryptoNote protocol. The smoothed issuance is designed to minimize the volatility seen in standard halving mechanics whereby the reward drops suddenly by half on a particular date. The Bitcoin stock-to-flow model lends support to the idea that this sudden reduction in supply is at least partly responsible for the extreme bull market/bear market cycles.
The sub-unit of the Zeno is the zent. A number with a large number (90) of divisors was chosen as the conversion factor between the zent and the Zeno:
This particular conversion factor is the 24th antiprime, or highly composite number, in the sequence of positive integers with a greater number of divisors than any smaller positive integer. This antiprime number has 90 divisors, and 9 prime factors. The use of a number with a large number of divisors facilitates the use of fractional payments without the need for rounding. At the same time we stay within the bounds of the u64 integer type employed in our codebase for the total cap in zenoshis of 10 billion x 25200 = 2.52e14.
The block reward in zenoshis is calculated using the total Zeno supply and the current Zeno supply in the market via the following formula:
The equation determining Zeno issuance, based on the CryptoNote protocol
In a practical network protocol, issuance must be implemented using bitwise operators, in order to ensure consistent performance across different hardware types. This allows operations to be performed on the bit level and therefore proceed at the maximum possible speed. Additionally, this approach ensures the consistency of floating point operations across different architecture types. In Bitcoin and bitcoin-like protocols this manifests requiring the block reward to drop by half (the ‘halving’) every n blocktimes. This is due to the bitshift operator being applied to the block reward (the left-hand side of the equation). We apply it to the recursive right-hand side of the issuance equation, which allows for a smoothed curve without the sudden halving jumps that likely have undesirable economic properties due to sudden supply shocks. Therefore, the block reward in zenoshis (for a 60 second blocktime) is given in practical terms by
$\text{reward} = (\text{total supply − current supply}) >> 25$
The issuance curve is shown in graphical form in the figure below. The emission is divided into two parts, with the miners taking the majority and the compute and storage nodes being allocated a small percentage that varies over time.
The issuance schedule for the Zeno in terms of the block reward, divided into miners (blue line) and the compute & storage nodes (magenta line) with the total for the network (black line). The issuance is smooth, rather than proceeding via the standard halving mechanic, in order to minimize the chance of extreme bull/bear market cycles driven by supply/demand shocks.
The fraction of the issuance allocated to the compute and storage nodes follows a reverse logistic function, starting at 15% and varying smoothly to 5% over a period of approx. 100 years. This is to reward the compute and storage nodes for the larger role that they play in the initial years of the network, and to recoup large capital costs, and to incentivize miners to play a larger role in the network later on.
Fraction of issuance allocated to the compute and storage nodes (magenta line in Figure 13) with time. The fraction allocation follows a reverse logistic function from an initial value of 15% and levelling out at 5%.
The form of this function is shown in the figure above. The total number of Zeno coins mined over time is shown in the figure below, along with the specific number mined by the mining, compute and storage nodes.
The total number of Zeno coins mined with time, showing the mining hard cap limit of 7.5 billion (the hard cap limit minus the treasury allocation; 10 billion - 2.5 billion). The black line shows the total earned by the network through mining, divided into two groups: the miners (blue line) and the compute & storage nodes (magenta line).
# Economic policy
The economic policy of Zenotta is focused around the goals of (i) coin value as a function of real economic activity and (ii) maximization of distribution. The Zenotta data protocol that allows for the creation of Smart Data assets is intrinsically linked to the Zenotta network protocol and the miners via a Socratic approach to democracy – if you put the work in to help secure the ledger, you earn the right to create tradeable assets. This keeps incentives aligned and ensures a healthy level of informed participation.
## An economy based on (distributed) goods & services
Boom-bust cycles in the mainstream global economy are largely due to a form of money creation that is funnelled into financial speculation rather than the creation of goods & services or productive innovation. Financial crashes – the ‘popping of the bubble’ – harm everyone, even those who were the architects of the bubble, unless they are among the lucky few to see it coming and get out at the right time. The trend of the ‘too big to fail’ banks creating money for risky, speculative investments that do not increase GDP has eroded the function of banks from helping the economy to harming it.
“More than 70% of all lending – actually way more than that – is money creation for financial transactions; for asset transactions; for purchasing ownership rights. Now, then you have a problem. Why? Because you are creating new money, but you are not creating new goods & services. You are simply giving somebody new purchasing power over existing assets, and therefore you must push up asset prices [...] and that also creates the inequality – when the banking sector has focused too much on unproductive lending."
– Prof. Richard Werner, episode of RT UK.
The crypto economy is still new and largely untested; however, it is thriving. The problem, though, is that money creation in the crypto economy has similar problems to those described above – when new tokens are created, usually as part of the block reward, there is no corresponding increase in goods services, beyond the function of the relevant blockchain network as an effective, fair, and efficient money transmitter. Ethereum’s world computer (and subsequent variants that have emerged) can arguably be said to funnel money creation into innovation (although most of that innovation to date has been to develop more ways to create money or increase speculative activity).
In the Smart Data economy provided by Zenotta, the creation of new money through mining can quickly and easily feed into the creation of Smart Data goods and services. Smart Data is itself created through the process of either mining or verifying the ledger, through a system of create credits whereby miners or those running a full verifying node are awarded the right to create Smart Data assets of their choosing (in other words, they are awarded with the ability to convert files into Smart Data files that can be traded on the Zenotta blockchain). In order to facilitate trade of Smart Data assets (goods & services) the Zenotta blockchain ledger is a new design of ledger that incorporates a dual double entry accounting of both the payment and the asset, such that the trade proceeds two-way, with both halves notarized by the blockchain. This makes the Zenotta blockchain a blockchain for trade rather than merely for payments.
The nature of data assets; namely, files, as the digital good being traded for in the blockchain ledger ensures a real and considerable level of a priori distribution and de- centralization. Everyone with a computer has a substantial number of files, and through the create credits system of validating or mining a small part of the network, coupled with the balanced mining approach outlined in the next section that reduces the vast inequality in mining power to acceptable limits, access to the ‘thing of value’ – the file – is far more distributed than any other type of good or service in any other economy (crypto or otherwise). Therefore, the economy provided by the Zenotta Digital System contains within it the ideal of equality of opportunity from the very start.
The value of an asset in any economy (for example a coin, or a token) can be expressed by the well-known formula below:
$\text{token value} = \frac{\text{economic activity}}{\substack{{\text{circulating}}\ {\text{token supply}}} \times \substack{{\text{consumer}}\ {\text{token velocity}}}}$
In the crypto space, the numerator of this equation is something of a problem. Since there is no (or very little) economic activity by the usual definition, assigning value to a crypto coin is difficult. Ultimately it is set by the market, but this is a price-based definition of value rather than a fundamental one. In the Zenotta digital economy, Zeno coins are used to purchase Smart Data and to provide the ‘gas’ for Smart Data contracts. With the Zeno coin, the economic activity is real, and therefore the value of the Zeno has a direct link to the value of the Smart Data being traded. The total value in the Zeno currency is therefore more akin to that of GDP, namely the GDP of the Smart Data economy.
## A distributed mint
For a blockchain-based economy the ‘mint’ is not a central body. Coins are created through the Proof-of-Work (PoW) consensus protocol and awarded to the miners upon winning the block. In this way we have a distributed mint, and so coin distribution begins in an already distributed state (relative to a central bank driven economy). We further optimise this distribution at the mint level by employing a thermodynamic-like protocol that brings the mining power of the entities in the network closer to balance, via a peer-to-peer algorithm. This approach increases the decentralization and distribution of mining power, which increases the security and the efficiency of the network, as well as the decentralization and distribution of the mining reward.
The full technical description of the balancing protocol is the subject of a separate paper, but briefly, the block processing power of the network (the ‘node temperature’) is moved towards a homogeneous distribution by decreasing the effective hashrate of the ‘hot’ nodes (e.g., the ASICs) and increasing it for the ‘cold’ nodes (e.g., the CPUs). This is done smoothly, allowing our node temperature quantity η to change between nodes pairwise using a simple differential equation, which for miner A takes the form:
$\frac{d\eta_A}{dt} = -\alpha \Delta \eta$
where ∆η ≡ηA−ηB, and α is a normalisation constant. As a result, the algorithm avoids a centralised controller and operates autonomously.
The desired end-state of the network is not one where the effective hashrate is completely balanced (which would bring its own undesirable economic properties and increase the attack surface for Sybil attacks on the network) but rather in-between the two extremes of the proportional model (where the probability of finding a block is proportional to hashrate) and the homogeneous model (where the probability of finding a block is equal for all participants) at a point where distribution is maximised and excess energy usage is minimised without increasing the net attack surface. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 3, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.604790449142456, "perplexity": 1749.3760573421189}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320302355.97/warc/CC-MAIN-20220120160411-20220120190411-00442.warc.gz"} |
https://fractalforums.org/forum-help-and-support/31/math-captcha-ambiguous/2076/msg10491 | • 5 Replies
• 367 Views
0 Members and 1 Guest are viewing this topic.
#### Silvus
• Fractal Freshman
• Posts: 1
« on: October 30, 2018, 09:07:35 PM »
I'm honestly sorry to make my first post a complaint, anyways:
I was unable to create an account because I misunderstood the captcha "What is the square root of one hunderd plus twelve?" I thought of it as $$\sqrt{100 + 12}$$ which does not really make sense - it is $$\sqrt{100} + 12$$. And even that has its problems: Entering "twentytwo" does not work - it requires "twenty two". I'm just glad it's not rate limited...
This might seem obvious in hindsight - but sadly isn't.
#### 3DickUlus
• 3f
• Posts: 1753
« Reply #1 on: October 31, 2018, 02:43:07 AM »
thanks for posting the answer now I'll have to come up with another one
your human brain did figure it out and, hopefully, you didn't need a calculator, the thing is: bots don't have brains and can only use a calculator, if it's too easy then it's just a nuisance and serves no purpose in helping keep bots from creating accounts.
Welcome aboard human!
#### Caleidoscope
• Moderator
• Posts: 494
« Reply #2 on: October 31, 2018, 01:52:45 PM »
thanks for posting the answer now I'll have to come up with another one
your human brain did figure it out and, hopefully, you didn't need a calculator, the thing is: bots don't have brains and can only use a calculator, if it's too easy then it's just a nuisance and serves no purpose in helping keep bots from creating accounts.
Welcome aboard human!
I'm glad I'm already registered, otherwise it would have been a daily challenge Is it so difficult to become a member on the FF?
And by the way Silvus, glad you join the forum! Welcome
#### 3DickUlus
• 3f
• Posts: 1753
« Reply #3 on: November 01, 2018, 12:42:43 AM »
I didn't think it would be a problem but Silvus is right, it's not math syntax it's english language, "take the square root of one hundred and add twelve" is perhaps the way it should have been worded, I'll try to keep this sort of thing in mind when making a new one
#### Caleidoscope
• Moderator
• Posts: 494
« Reply #4 on: November 01, 2018, 09:44:12 AM »
I didn't think it would be a problem but Silvus is right, it's not math syntax it's english language, "take the square root of one hundred and add twelve" is perhaps the way it should have been worded, I'll try to keep this sort of thing in mind when making a new one
We're glad you take care of it, and keep the bots out.
#### Fraktalist
• Strange Attractor
• Posts: 1167
« Reply #5 on: November 02, 2018, 09:24:52 PM »
make it a little easier please. many are here for the art and "easy" math is relative.
### Similar Topics
###### "Time Span"
Started by cricke49 on Fractal Image Gallery
0 Replies
589 Views
August 02, 2018, 07:05:21 AM
by cricke49
###### OpenGL font rendering
Started by sjhalayka on Programming
2 Replies
183 Views
April 20, 2020, 05:00:47 PM
by sjhalayka
###### QAction::event: Ambiguous shortcut overload: Ctrl+R
Started by claude on Fragmentarium
2 Replies
210 Views
January 17, 2019, 02:19:22 AM
by 3DickUlus
Started by claude on Forum Help And Support
4 Replies
262 Views
December 13, 2018, 03:03:05 AM
by 3DickUlus
###### Birdie Style
Started by gannjondal on Fractal Image Gallery
1 Replies
618 Views
May 08, 2018, 02:39:37 PM
by who8mypnuts | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5999153852462769, "perplexity": 5084.331889669278}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-34/segments/1596439740848.39/warc/CC-MAIN-20200815124541-20200815154541-00228.warc.gz"} |
https://www.physicsforums.com/threads/dirac-delta-cosx.221157/ | # Dirac Delta Cosx
1. Mar 10, 2008
### apw235
1. The problem statement, all variables and given/known data
The function $$\delta(cosx)$$ can be written as a sum of Dirac delta functions:
$$\delta(cosx)=\sum_{n} a_{n}\delta(x-x_{n})$$
Find the range for n and the values for $$a_{n}$$ and $$x_{n}$$
3. The attempt at a solution
Well, taking the integral of $$\delta(cosx)$$, we only get spikes when x is an even multiple of $$\frac{\pi}{2}$$. So shouldn't n run to infinity? Thats all i have so far, any help would be appreciated. thanks.
-Adrian
2. Mar 10, 2008
### Dick
You get 'spikes' where cos(x)=0. I wouldn't describe those as 'even multiples of pi/2'. In general if x_i are the roots of f(x)=0, then delta(f(x)) is the sum of delta(x_i)/|f'(x_i)|.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook
Have something to add?
Similar Discussions: Dirac Delta Cosx | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9280867576599121, "perplexity": 1522.7855824518529}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-04/segments/1484560281659.81/warc/CC-MAIN-20170116095121-00415-ip-10-171-10-70.ec2.internal.warc.gz"} |
http://mfat.imath.kiev.ua/authors/name/?author_id=305 | # L. E. Bazylevych
Search this author in Google Scholar
Articles: 1
### On the hyperspace of max-min convex compact sets
L. E. Bazylevych
Methods Funct. Anal. Topology 15 (2009), no. 4, 322-332
A subset $A$ of $\mathbb R^n$ is said to be max-min convex if, for any $x,y\in A$ and any $t\in \mathbb R$, we have $x\oplus t\otimes y\in A$ (here $\oplus$ stands for the coordinatewise maximum of two elements in $\mathbb R^n$ and $t\otimes (y_1,\dots,y_n)=(\min\{t,y_1\},\dots, \min\{t,y_n\})$). It is proved that the hyperspace of compact max-min convex sets in the Euclidean space $\mathbb R^n$, $n\ge2$, is homeomorphic to the punctured Hilbert cube. This is a counterpart of the result by Nadler, Quinn and Stavrokas proved for the hyperspace of compact convex sets. We also investigate the maps of the hyperspaces of compact max-min convex sets induced by the projection maps of Euclidean spaces. It is proved that this map is a Hilbert cube manifold bundle. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9694966077804565, "perplexity": 263.68250958820937}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-21/segments/1620243991514.63/warc/CC-MAIN-20210518191530-20210518221530-00214.warc.gz"} |
https://spectre-code.org/structNewtonianEuler_1_1Sources_1_1LaneEmdenGravitationalField.html | NewtonianEuler::Sources::LaneEmdenGravitationalField Struct Reference
Source giving the acceleration due to gravity in the spherical, Newtonian Lane-Emden star solution. More...
#include <LaneEmdenGravitationalField.hpp>
## Public Types
using sourced_variables = tmpl::list< Tags::MomentumDensity< 3 >, Tags::EnergyDensity >
using argument_tags = tmpl::list< Tags::MassDensityCons, Tags::MomentumDensity< 3 >, ::Tags::AnalyticSolution< NewtonianEuler::Solutions::LaneEmdenStar >, domain::Tags::Coordinates< 3, Frame::Inertial > >
## Public Member Functions
LaneEmdenGravitationalField (const LaneEmdenGravitationalField &)=default
LaneEmdenGravitationalFieldoperator= (const LaneEmdenGravitationalField &)=default
LaneEmdenGravitationalField (LaneEmdenGravitationalField &&) noexcept=default
LaneEmdenGravitationalFieldoperator= (LaneEmdenGravitationalField &&) noexcept=default
void pup (PUP::er &) noexcept
## Static Public Member Functions
static void apply (gsl::not_null< tnsr::I< DataVector, 3 > * > source_momentum_density, gsl::not_null< Scalar< DataVector > * > source_energy_density, const Scalar< DataVector > &mass_density_cons, const tnsr::I< DataVector, 3 > &momentum_density, const NewtonianEuler::Solutions::LaneEmdenStar &star, const tnsr::I< DataVector, 3 > &x) noexcept
## Detailed Description
Source giving the acceleration due to gravity in the spherical, Newtonian Lane-Emden star solution.
The gravitational field $$g^i$$ enters the NewtonianEuler system as source terms for the conserved momentum and energy:
\begin{align*} \partial_t S^i + \partial_j F^{j}(S^i) &= S(S^i) = \rho g^i \partial_t e + \partial_j F^{j}(e) &= S(e) = S_i g^i, \end{align*}
where $$S^i$$ is the conserved momentum density, $$e$$ is the conserved energy, $$F^{j}(u)$$ is the flux of the conserved quantity $$u$$, and $$\rho$$ is the fluid mass density.
Note
This source is specialized to the Lane-Emden solution because it queries a LaneEmdenStar analytic solution for the gravitational field that generates the fluid acceleration. This source does not integrate the fluid density to compute a self-consistent gravitational field (i.e., as if one were solving a coupled Euler + Poisson system).
The documentation for this struct was generated from the following files:
• src/Evolution/Systems/NewtonianEuler/Sources/LaneEmdenGravitationalField.hpp
• src/Evolution/Systems/NewtonianEuler/Sources/LaneEmdenGravitationalField.cpp | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9386298656463623, "perplexity": 16734.48303870877}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-50/segments/1606141715252.96/warc/CC-MAIN-20201202175113-20201202205113-00717.warc.gz"} |
https://www.physicsforums.com/threads/sum-of-all-integrers-of-a-certain-degree.94714/ | # Sum of all integrers of a certain degree
1. Oct 14, 2005
### Werg22
Is there a general formula for the sum all the terms of the a serie such as:
1^n + 2^n + 3^n ... a^n
?
2. Oct 14, 2005
### Robokapp
well, as far as i know, the formulas differ depending on the power. I don't think that you can generalize a rhiemann summation like that...although it would defenetly be useful.
i know that sum(n) = n(n-1)/2
sum(n^2)=n(n-1)(n-2)/6
and so on...but i never had to memorize them so i might be wrong about the second one...if there was a way to combine all of them no matter the power, it should be in the precalculus manuals i think.
3. Oct 14, 2005
### ktoz
This looks like one
I was looking for this a few weeks ago and found one here:
http://mathworld.wolfram.com/FaulhabersFormula.html" [Broken]
Also, google: "general power series sum" or variation and you should get quite a few hits
Last edited by a moderator: May 2, 2017
4. Oct 14, 2005
### mathman
There is a standard reference "Table of Integrals, Series, and Products" by Gradshteyn and Ryzhik, published by Academic Press. The answer gets fairly complicated in n. It is a polynomial in degree n+1 without a constant term and sometimes without a linear term. Specifically there are terms in n+1, n, n-1, n-3, n-5, etc.
5. Oct 16, 2005
### ktoz
Another way to do it
I came up with another general way. Borrows a bit from Faulhaber's formula but it's a little simpler and might be a little faster as it uses fewer factorials and no Bernoulli numbers
$$\sum_{j=0}^m j^p \quad = \quad p! \sum_{j=0}^m Q_{pj} R_{pmj}$$
$$Q_{pk} \quad = \quad \left\{ \begin{array}{ll} \sum_{j=0}^k -1^j \frac{ (k - j + 1)^p}{j!(p - j)!} \quad & k < p \\ 1 & k \geq p \end{array}$$
$$R_{pmk} \quad = \quad \prod_{l=1}^p 1 + \frac{m - l}{k}$$
Last edited: Oct 17, 2005
6. Oct 17, 2005
### Karlsen
There's a typo there, it should be
sum(n^2)=n(n+1)(2n+1)/6.
Although n(n-1)(n-2)/6 will always return a possitve integer for n > 2, it does not give you the desired number.
7. Oct 20, 2005
### benorin
Here's one using Lagrange Interpolating Polynomials
Here's one using Lagrange Interpolating Polynomials (eqivalent to simplified polynomial curve fitting here).
$$\sum_{k=1}^{n}k^{p}=\sum_{k=1}^{p+2}\left(\sum_{m=1}^{k}m^{p}\prod_{j=1}^{p+2}\frac{n-j}{k-j}\right)$$
where, in the product, the terms with j=k are omitted.
Last edited: Oct 20, 2005
8. Oct 20, 2005
### Werg22
Alright. I hope the proof of those sum is not tied to integral as I was looking for such a thing in order to proove the integral!
9. Oct 21, 2005
### benorin
You can use bivariate induction to prove the above sum. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8570365309715271, "perplexity": 1281.7778739341736}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-51/segments/1544376828697.80/warc/CC-MAIN-20181217161704-20181217183704-00221.warc.gz"} |
https://www.physicsforums.com/threads/projectile-motion-at-an-angle.649998/ | Projectile motion at an angle
1. Nov 6, 2012
Precepts
Hi, I need someone to check if I did this right. As I got the q's off a PDF with no answers.
1. The problem statement, all variables and given/known data
A projectile is shot from the edge of a cliff 125 m above the ground. It has an initial velocity 50.0 m/s 37.0° above the horizontal at the launch point. a) Determine the time taken to reach the ground. b) How far is this point from the base of the cliff? c) What is the magnitude and direction of the final velocity just before the point of impact?
It doesn't specify what value to use for gravity, I assumed g, or a, is = -9.8m/s^2
(Doesn't matter since there's no answers anyway)
2. Relevant equations
v = u + at
s = ut (horizontal sense)
3. The attempt at a solution
I used this to find the time for a)
Vv = Uv + Avt
0 = 50 * sin37 - 9.8t
9.8t = 50 * sin37
t = 3.1s
b) Sh = Uh * t
= 50 * cos37 * 3.1
Sh = 123.79m
c) Vertical component before impact:
Vv = Uv + Avt
= 60.47m/s
I then used Pythagoras' to find v = 72.47m/s
and theta = 56'33'' above the horizontal.
I feel that I went wrong somewhere, can someone check if these are right/close. Not sure If I copied everything down correctly either, my page is a bit of a mess.
edit - I just noticed I didn't once use the vertical distance, I think I'll have another look at it.
edit 2 - Sv = Uvt + 1/2At^2
125 = 50 sin 37t -4.9t^2
= 30.1t - 4.9t^2
-4.9t^2 + 30.1t - 125 = 0
4.9t^2 - 30.1t +125 = 0
And... I'm getting math error when using quadratic formula. Not quite sure where to go from here...I realise now that the value for t that I had would only reach to the same height on the other side of the parabola... I'll have a look at this question again later.
Last edited: Nov 6, 2012
2. Nov 6, 2012
Basic_Physics
a)Vv = Uv + Avt
0 = 50 * sin37 - 9.8t
9.8t = 50 * sin37
t = 3.1s
The vertical component of the speed is not 0 when it hits the ground!
3. Nov 6, 2012
Precepts
Right, lol.
Can you find t? I tried to incorporate the height and use the quadratic formula, but it wouldn't solve. Kind of stuck here.
4. Nov 6, 2012
Precepts
Found it. I had to use a negative displacement for the height.... I was getting a negative square root prior. Wow.....
Similar Discussions: Projectile motion at an angle | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9069045782089233, "perplexity": 1068.4745392827876}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-51/segments/1512948522343.41/warc/CC-MAIN-20171213084839-20171213104839-00334.warc.gz"} |
https://www.englanniksi.com/sanakirja/rata | rata
railway, rink, course, sheet, right, trajectory, range, path, track, lane, rata, circle, true, reject
Esimerkkilauseet
: We played hockey all winter until the rink melted.
: The Schmirler rink won the Silver Broom.
: ux|en|The normal course of events seems to be just one damned thing after another.
*: The course of true love never did run smooth.
*: Day and night, / Seedtime and harvest, heat and hoary frost, / Shall hold their course.
: ux|en|I need to take a French course.
*: During the whole time of his abode in the university he generally spent thirteen hours of the day in study; by which assiduity besides an exact dispatch of the whole course of philosophy, he read over in a manner all classic authors that are extant...
: ux|en|We offer seafood as the first course.
*: He appointed ... the courses of the priests.
: ux|en|His illness ran its course.
: ux|en|The cross-country course passes the canal.
: ux|en|The ship changed its course 15 degrees towards south.
: ux|en|A course was plotted to traverse the ocean.
: ux|en|Main course and mainsail are the same thing in a sailing ship.
: ux|en|On a building that size, two crews could only lay two courses in a day.
: The oil coursed through the engine.
: Blood pumped around the human body courses throughout all its veins and arteries.
*: He is a South American, so perhaps revolutionary spirit courses through Franciss veins. But what, pray, does the Catholic church want with doubt?
*: The bounding steed courses the dusty plain.
*: We coursed him at the heels.
: to course greyhounds after deer
*: He fell into a trance, and saw heaven opened, and a certain vessel descending unto him, as it had been a great sheet knit at the four corners.
*: If I do die before thee, prithee, shroud me / In one of those same sheets.
: rfquotek|Dryden
: fore sheets; stern sheets
: Remember to sheet the floor before you start painting.
*: Yea, like a stag, when snow the pasture sheets, / The barks of trees thou browsedst.
: We couldnt go out because the rain was sheeting down all day long.
: a right line
: The kitchen counter formed a right angle with the back wall.
: I thought youd made a mistake, but it seems you were right all along.
: Its not right that one person gets all the credit for the groups work.
*: If there be no prospect beyond the grave, the inference is ... right, "Let us eat and drink, for to-morrow we die."
*: ... there are some dispositions blame-worthy in men, which are yet, in a right sense, holily ascribed unto God; as unchangeableness, and irrepentance.
: Is this the right software for my computer?
: Im afraid my father is no longer in his right mind.
: Youve made a right mess of the kitchen!
*: In this battle, ... the Britons never more plainly manifested themselves to be right barbarians.
*: KIRSTY: I suppose youre hungry. Would you like something to eat? / KEN: No. Im right, thanks.
*: When the sales assistant sees the customer, she asks Are you right, sir? This means Are you all right? She wants to know if he needs any help.
*: You lost? / Colin spun round. Looking at him was a nurse, her eyebrows raised. / No, Im right, thanks, said Colin.
: After the accident, her right leg was slightly shorter than her left.
: the right side of a piece of cloth
: - After that interview, I dont think we should hire her.
- Right — who wants lunch?
: Youre going, right?
*: Withnail: Right ... Im gonna do the washing up.
: ux|en|Were on the side of right in this contest.
: ux|en|You have no right to go through my personal diary.
*: There are no rights whatever, without corresponding duties.
: ux|en|The pharmacy is just on the right past the bookshop.
: ux|en|The political right holds too much power.
: Righting all the wrongs of the war will be impossible.
: The tow-truck righted what was left of the automobile.
: When the wind died down, the ship righted.
: to right the oppressed
*: So just is God, to right the innocent.
*: All experience hath shown that mankind are more disposed to suffer while evils are sufferable, than to right themselves by abolishing the forms to which they are accustomed.
: ux|en|The arrow landed right in the middle of the target.
: ux|en|Luckily we arrived right at the start of the film.
: ux|en|Cant you see it? Its right beside you!
: ux|en|Tom was standing right in front of the TV, blocking everyones view.
: ux|en|I made a right stupid mistake there, didnt I?
: ux|en|I stubbed my toe a week ago and it still hurts right much.
*: The fog was right hard to see through so I was on Tom Pritchard before I saw him.
: ux|en|Do it right or dont do it at all.
: ux|en|Sir, I am right glad to meet you …
: ux|en|Members of the Queens Privy Council are styled The Right Honourable for life.
: ux|en|The Right Reverend Monsignor Guido Sarducci.
*: Therein an hundred raunges weren pight, / And hundred fornaces all burning bright;
*: He was bid at his first coming to take off the range, and let down the cinders.
: ux|en|We sell a wide range of cars.
: ux|en|We could see the ship at a range of five miles.
: ux|en|One can use the speed of sound to estimate the range of a lightning flash.
: ux|en|This missiles range is 500 kilometres.
*: Far as creations ample range extends.
*: The range and compass of Hammonds knowledge filled the whole circle of the arts.
*: A man has not enough range of thought.
: ux|en|Jones has good range for a big man.
: ux|en|`std::for_each` calls the given function on each value in the input range.
*: The next range of beings above him are the immaterial intelligences.
: rfquotek|Clarendon
*: He may take a range all the world over.
: to range the fields
*: Teach him to range the ditch, and force the brake.
*: The soule is variable in all manner of formes, and rangeth to her selfe, and to her estate, whatsoever it be, the senses of the body, and all other accidents.
*: At last we gained such an offing, that the two pilots were needed no longer. The stout sail-boat that had accompanied us began ranging alongside.
*: In ranging herself as a partisan on the side of Major Pallaby Mrs. Hoopington had been largely influenced by the fact that she had made up her mind to marry him at an early date.
: ux|en|The variable x ranges over all [[real]] values from 0 to 10.
: to range plants and animals in genera and species
: The front of a house ranges with the street.
*: which way the forests range
*: The street-lamps burn amid the baleful glooms, / Amidst the soundless solitudes immense / Of ranged mansions dark and still as tombs.
*: And range with humble livers in content.
*: Maccabeus ranged his army by hands.
*: It would be absurd in me to range myself on the side of the Duke of Bedford and the corresponding society.
: The peba ranges from Texas to Paraguay.
: rfquotek|Holland
: to range the coast
*: Willie, playing in left-center, raced toward a ball no human had any business getting a glove to. Mays ranged to his left, searching, digging in, pouring on the speed, as the crowd screamed its anticipation of a triple.* seeMoreCites
*: Just before Warwick reached Liberty Point, a young woman came down Front Street from the direction of the market-house. When their paths converged, Warwick kept on down Front Street behind her, it having been already his intention to walk in this direction.
: ux|en|the path of a meteor, of a caravan, or of a storm
*: All the paths of the Lord are mercy and truth.
*: The paths of glory lead but to the grave.
*: pathing young Henrys unadvised ways
*: small tracks of ground
: ux|en|Im going to try out for track next week.
: We will track the raven population over the next six months.
: Agent Miles has been tracking the terrorist since Madrid.
: My height tracks my fathers at my age, so I might end up as tall as him.
: The camera tracked the ball even as the field of play moved back and forth, keeping the action in shot the entire time.
: The hurricane tracked further west than expected.
: My uncle spent all day tracking the deer, whose hoofprints were clear in the mud.
: I tracked Joe to his friends bedroom, where he had spent the night.
: In winter, my cat tracks mud all over the house.
: Lil Kyle is gonna track with that DJ next week.
: We travelled to the seaside by rail.
: a small Scottish village not accessible by rail
*: Rails alone can only ever have a marginal effect on a boards general turning ability.
*: Mottram of the Indian Survey had ridden thirty and railed one hundred miles from his lonely post in the desert ...
*: It ought to be fenced in and railed.
*: They were brought to London all railed in ropes, like a team of horses in a cart.
*: Chief Joyi railed against the white man, whom he believed had deliberately sundered the Xhosa tribe, dividing brother from brother.
: rfquotek|Fairholt
*: his breste and his brayle was bloodé – and hit rayled all over the see.
*: So furiously each other did assayle, / As if their soules they would attonce haue rent / Out of their brests, that streames of bloud did rayle / Adowne, as if their springes of life were spentnb....
: The set of all points (x, y) such that (x-1)2 + y2 = r2 is a circle of radius r around nowrap|the point (1, 0).
: ux|en|Put on your dunce-cap and sit down on that circle.
: ux|en|move in a circle
: ux|en|inner circle; circle of friends
*: As his name gradually became known, the circle of his acquaintance widened.
*: At half-past nine on this Saturday evening, the parlour of the Salutation Inn, High Holborn, contained most of its customary visitors....In former days every tavern of repute kept such a room for its own select circle, a club, or society, of habitués, who met every evening, for a pipe and a cheerful glass.
*: “I dont mean all of your friends—only a small proportion—which, however, connects your circle with that deadly, idle, brainless bunch—the insolent chatterers at the opera, the gorged dowagers,nb..., the jewelled animals whose moral code is the code of the barnyard—!"
*: The Rabbit could not claim to be a model of anything, for he didn’t know that real rabbits existed; he thought they were all stuffed with sawdust like himself, and he understood that sawdust was quite out-of-date and should never be mentioned in modern circles.
*: He arrived at the lakefront and drove around the circle where the amusement park and beach used to be when he was a kidnb...
*: in the circle of this forest
*: Thus in a circle runs the peasants pain.
*: That heavy bodies descend by gravity; and, again, that gravity is a quality whereby a heavy body descends, is an impertinent circle and teaches nothing.
*: Has he given the lie, / In circle, or oblique, or semicircle.
: ux|en|The ten Circles of the Holy Roman Empire were those principalities or provinces which had seats in the German Diet.
: After working all night, she had circles under her eyes.
*: Other planets circle other suns.
*: Their heads are circled with a short turban.
*: So he lies, circled with evil.
: Circle the jobs that you are interested in applying for.
: ux|en|This is a true story.
: ux|en|a true copy; a true likeness of the original
*: making his eye, foot, and hand keep true time
: ux|en|"A and B" is true if and only if "A" is true and "B" is true.
: ux|en|He’s turned out to be a true friend.
: ux|en|This is true Parmesan cheese.
: ux|en|The true king has returned!
*: Let $Z_t$ be twice the value of a true die shown on the $t$-th toss.
*: In fact, few profit margins can be predicted with such reliability as those provided by a true roulette wheel or other game of chance.
*: We do not reject, because 9 heads and 3 tails is in a set of reasonably likely results when we toss a true coin.
: ux|en|this gun shoots true
*: Some toolmakers are very careless when drilling the first hole through work that is to be bored, claiming that if the drilled hole comes out of true somewhat it can be brought true with the boring tool.
*: She clapped her hands happily, and he thought how pretty she was really, that is, the upper part of her face—from the bridge of the nose down she was somewhat out of true.
*: The crate shifted on its pallet, out of sync now. As the lift withdrew, the crate skidded with it, dragged by friction and gravity, skewing farther and farther from true.
*: The strength and number of blows depends on how far out of true the shafts are.
: He trued the spokes of the bicycle wheel.
: We spent all night truing up the report.
: ux|en|She even rejected my improved offer.
suositut haut
liturgia etsintä röyhtäys aasintamma kannattaa sohvaperuna | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 2, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.27302414178848267, "perplexity": 8540.0471178601}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320305494.6/warc/CC-MAIN-20220128104113-20220128134113-00057.warc.gz"} |
https://fr.maplesoft.com/support/help/addons/view.aspx?path=GaussAGM | GaussAGM - Maple Help
GaussAGM
Gauss' arithmetic geometric mean
Calling Sequence GaussAGM(a, b)
Parameters
a - expression denoting a complex number b - expression denoting a complex number
Description
• GaussAGM(a, b) is the limit of the iteration
${a}_{0}≔a$
${b}_{0}≔b$
${a}_{n+1}≔\frac{{a}_{n}}{2}+\frac{{b}_{n}}{2}$
${b}_{n+1}≔\left({a}_{n}+{b}_{n}\right)\sqrt{\frac{{a}_{n}{b}_{n}}{{\left({a}_{n}+{b}_{n}\right)}^{2}}}$
for n=0,1,2,3,... (See arithmetic-geometric mean iteration.)
• The GaussAGM of two positive real numbers a and b lies between their arithmetic mean
$\frac{a}{2}+\frac{b}{2}$
• and their geometric mean
$\sqrt{ab}$
• Each step of the iteration used to compute the GaussAGM computes an arithmetic mean and a geometric mean which explains the name GaussAGM. Lagrange discovered the arithmetic geometric mean before 1785. Gauss rediscovered it in the 1790s and Gauss and Legendre developed the most complete theory of its use. GaussAGM can also be defined in terms of elliptic integrals
${\mathrm{GaussAGM}}{}\left({a}{,}{b}\right){=}\frac{{\mathrm{\pi }}{}\left({a}{+}{b}\right)}{{4}{}{\mathrm{EllipticK}}{}\left(\sqrt{\frac{{\left({a}{-}{b}\right)}^{{2}}}{{\left({a}{+}{b}\right)}^{{2}}}}\right)}$ (1)
> $\mathrm{GaussAGM}\left(2.0,3.0\right)$
${2.474680436}$ (2) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 9, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9938839673995972, "perplexity": 2137.8735129295774}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-21/segments/1652662552994.41/warc/CC-MAIN-20220523011006-20220523041006-00203.warc.gz"} |
http://lists.gnu.org/archive/html/emacs-orgmode/2011-06/msg00529.html | emacs-orgmode
[Top][All Lists]
## Re: [O] latex checkboxes
From: Skip Collins Subject: Re: [O] latex checkboxes Date: Thu, 16 Jun 2011 21:37:05 -0400
On Thu, Jun 16, 2011 at 6:52 PM, Nick Dokos <address@hidden> wrote:
> I like it! Well, almost all of it: I'd vote for \large, rather than \LARGE,
> but otherwise it looks good to me.
Can we compromise on \Large ? :-)
> ,----
> | \item [{\parbox[][][c]{\wd0}{\LARGE$\square$}}] a
> ----
I tried the optional preamble for \item in a very naive fashion. LaTeX
threw an error. Maybe I did it wrong. Or maybe the preamble is
fragile. Regardless, there is probably a simple solution. Even for
enumerated lists, it makes sense to place the checkbox with the list
number rather than with the item text.
Regarding the extra square brackets after \parbox, I was just using
the documentation I found at
http://www.tug.org/tutorials/latex2e/\$5cparbox.html :
\parbox[position][height][inner-pos]{width}{text}
A parbox is a box whose contents are created in paragraph mode. The
\parbox has two mandatory arguments:
width - specifies the width of the parbox, and
text - the text that goes inside the parbox.
LaTeX will position a parbox so its centre lines up with the centre of
the text line. The optional position argument allows you to line up
either the top or bottom line in the parbox (default is top).
If the height argument is not given, the box will have the natural
height of the text.
The inner-pos argument controls the placement of the text inside the
box. If it is not specified, position is used.
t --- text is placed at the top of the box.
c --- text is centred in the box.
b --- text is placed at the bottom of the box.
s --- stretch vertically. The text must contain vertically stretchable
space for this to work.
A \parbox command is used for a parbox containing a small piece of
text, with nothing fancy inside. In particular, you shouldn't use any
of the paragraph-making environments inside a \parbox argument. For
larger pieces of text, including ones containing a paragraph-making
environment, you should use a minipage environment See minipage.
` | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9805284738540649, "perplexity": 5607.460256561469}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368696383077/warc/CC-MAIN-20130516092623-00098-ip-10-60-113-184.ec2.internal.warc.gz"} |
https://www.physicsoverflow.org/23811/anomalies-in-qft-books | # Anomalies in QFT books
+ 3 like - 1 dislike
192 views
Why in most QFT books when author discusses of non-invariance of measure of path integral (massless fermions interact with gauge fields) $$\int D\bar{\Psi} D\Psi \to |\Psi \to U\Psi , \quad \bar{\Psi} \to \bar{\Psi} \bar{U},\quad U = e^{i \alpha (x) \gamma_{5}t},$$
$$\quad t^{\dagger} =t| \to \int D\bar{\Psi} D\Psi \det \left( U \right)^{-2}$$ and looks only on infinitesimal transformations $U \approx 1 + i\alpha(x)\gamma_{5}t$ he doesn't introduce something like fictive particles (fictive, but formally independent) called ghosts in non-abelian gauge theories? Instead of this he introduces something like monster (like in Weinberg's "QFT" Vol. 2) $$\int D\bar{\Psi} D\Psi \to \int D\bar{\Psi} D\Psi e^{-2i\int d^{4}xTr \left[\gamma_{5}tf \left( \frac{(\gamma_{\mu}D^{\mu}_{x})^{2}}{M^{2}}\right)\delta (x - y)\right]_{y \to x}},$$ which is equal to summation over eigenstates of $\gamma_{\mu}D^{\mu}$ operator without introducing the new fields.
I don't understand this.
This post imported from StackExchange Physics at 2014-09-17 10:15 (UCT), posted by SE-user PhysiXxx
Please use answers only to (at least partly) answer questions. To comment, discuss, or ask for clarification, leave a comment instead. To mask links under text, please type your text, highlight it, and click the "link" button. You can then enter your link URL. Please consult the FAQ for as to how to format your post. This is the answer box; if you want to write a comment instead, please use the 'add comment' button. Live preview (may slow down editor) Preview Your name to display (optional): Email me at this address if my answer is selected or commented on: Privacy: Your email address will only be used for sending these notifications. Anti-spam verification: If you are a human please identify the position of the character covered by the symbol $\varnothing$ in the following word:p$\hbar$ys$\varnothing$csOverflowThen drag the red bullet below over the corresponding character of our banner. When you drop it there, the bullet changes to green (on slow internet connections after a few seconds). To avoid this verification in future, please log in or register. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5314173102378845, "perplexity": 2311.7553891337466}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-39/segments/1537267155817.29/warc/CC-MAIN-20180919024323-20180919044323-00303.warc.gz"} |
https://www.lmfdb.org/ModularForm/GL2/Q/holomorphic/637/2/r/c/ | # Properties
Label 637.2.r.c Level $637$ Weight $2$ Character orbit 637.r Analytic conductor $5.086$ Analytic rank $0$ Dimension $4$ CM no Inner twists $4$
# Related objects
## Newspace parameters
Level: $$N$$ $$=$$ $$637 = 7^{2} \cdot 13$$ Weight: $$k$$ $$=$$ $$2$$ Character orbit: $$[\chi]$$ $$=$$ 637.r (of order $$6$$, degree $$2$$, not minimal)
## Newform invariants
Self dual: no Analytic conductor: $$5.08647060876$$ Analytic rank: $$0$$ Dimension: $$4$$ Relative dimension: $$2$$ over $$\Q(\zeta_{6})$$ Coefficient field: $$\Q(\zeta_{12})$$ Defining polynomial: $$x^{4} - x^{2} + 1$$ Coefficient ring: $$\Z[a_1, \ldots, a_{5}]$$ Coefficient ring index: $$1$$ Twist minimal: yes Sato-Tate group: $\mathrm{SU}(2)[C_{6}]$
## $q$-expansion
Coefficients of the $$q$$-expansion are expressed in terms of a primitive root of unity $$\zeta_{12}$$. We also show the integral $$q$$-expansion of the trace form.
$$f(q)$$ $$=$$ $$q + 2 \zeta_{12} q^{2} + 2 \zeta_{12}^{2} q^{3} + 2 \zeta_{12}^{2} q^{4} + \zeta_{12} q^{5} + 4 \zeta_{12}^{3} q^{6} + ( -1 + \zeta_{12}^{2} ) q^{9} +O(q^{10})$$ $$q + 2 \zeta_{12} q^{2} + 2 \zeta_{12}^{2} q^{3} + 2 \zeta_{12}^{2} q^{4} + \zeta_{12} q^{5} + 4 \zeta_{12}^{3} q^{6} + ( -1 + \zeta_{12}^{2} ) q^{9} + 2 \zeta_{12}^{2} q^{10} + ( -2 \zeta_{12} + 2 \zeta_{12}^{3} ) q^{11} + ( -4 + 4 \zeta_{12}^{2} ) q^{12} + ( -2 + 3 \zeta_{12}^{3} ) q^{13} + 2 \zeta_{12}^{3} q^{15} + ( 4 - 4 \zeta_{12}^{2} ) q^{16} + 6 \zeta_{12}^{2} q^{17} + ( -2 \zeta_{12} + 2 \zeta_{12}^{3} ) q^{18} -3 \zeta_{12} q^{19} + 2 \zeta_{12}^{3} q^{20} -4 q^{22} + ( 3 - 3 \zeta_{12}^{2} ) q^{23} -4 \zeta_{12}^{2} q^{25} + ( -6 - 4 \zeta_{12} + 6 \zeta_{12}^{2} ) q^{26} + 4 q^{27} + 3 q^{29} + ( -4 + 4 \zeta_{12}^{2} ) q^{30} + ( 3 \zeta_{12} - 3 \zeta_{12}^{3} ) q^{31} + ( 8 \zeta_{12} - 8 \zeta_{12}^{3} ) q^{32} -4 \zeta_{12} q^{33} + 12 \zeta_{12}^{3} q^{34} -2 q^{36} -6 \zeta_{12} q^{37} -6 \zeta_{12}^{2} q^{38} + ( -6 \zeta_{12} - 4 \zeta_{12}^{2} + 6 \zeta_{12}^{3} ) q^{39} -10 \zeta_{12}^{3} q^{41} + q^{43} -4 \zeta_{12} q^{44} + ( -\zeta_{12} + \zeta_{12}^{3} ) q^{45} + ( 6 \zeta_{12} - 6 \zeta_{12}^{3} ) q^{46} -11 \zeta_{12} q^{47} + 8 q^{48} -8 \zeta_{12}^{3} q^{50} + ( -12 + 12 \zeta_{12}^{2} ) q^{51} + ( -6 \zeta_{12} - 4 \zeta_{12}^{2} + 6 \zeta_{12}^{3} ) q^{52} + 9 \zeta_{12}^{2} q^{53} + 8 \zeta_{12} q^{54} -2 q^{55} -6 \zeta_{12}^{3} q^{57} + 6 \zeta_{12} q^{58} + ( -8 \zeta_{12} + 8 \zeta_{12}^{3} ) q^{59} + ( -4 \zeta_{12} + 4 \zeta_{12}^{3} ) q^{60} + ( 8 - 8 \zeta_{12}^{2} ) q^{61} + 6 q^{62} + 8 q^{64} + ( -3 - 2 \zeta_{12} + 3 \zeta_{12}^{2} ) q^{65} -8 \zeta_{12}^{2} q^{66} + ( 12 \zeta_{12} - 12 \zeta_{12}^{3} ) q^{67} + ( -12 + 12 \zeta_{12}^{2} ) q^{68} + 6 q^{69} + 14 \zeta_{12}^{3} q^{71} + ( -9 \zeta_{12} + 9 \zeta_{12}^{3} ) q^{73} -12 \zeta_{12}^{2} q^{74} + ( 8 - 8 \zeta_{12}^{2} ) q^{75} -6 \zeta_{12}^{3} q^{76} + ( -12 - 8 \zeta_{12}^{3} ) q^{78} + ( 9 - 9 \zeta_{12}^{2} ) q^{79} + ( 4 \zeta_{12} - 4 \zeta_{12}^{3} ) q^{80} + 11 \zeta_{12}^{2} q^{81} + ( 20 - 20 \zeta_{12}^{2} ) q^{82} -11 \zeta_{12}^{3} q^{83} + 6 \zeta_{12}^{3} q^{85} + 2 \zeta_{12} q^{86} + 6 \zeta_{12}^{2} q^{87} + 5 \zeta_{12} q^{89} -2 q^{90} + 6 q^{92} + 6 \zeta_{12} q^{93} -22 \zeta_{12}^{2} q^{94} -3 \zeta_{12}^{2} q^{95} + 16 \zeta_{12} q^{96} + 9 \zeta_{12}^{3} q^{97} -2 \zeta_{12}^{3} q^{99} +O(q^{100})$$ $$\operatorname{Tr}(f)(q)$$ $$=$$ $$4q + 4q^{3} + 4q^{4} - 2q^{9} + O(q^{10})$$ $$4q + 4q^{3} + 4q^{4} - 2q^{9} + 4q^{10} - 8q^{12} - 8q^{13} + 8q^{16} + 12q^{17} - 16q^{22} + 6q^{23} - 8q^{25} - 12q^{26} + 16q^{27} + 12q^{29} - 8q^{30} - 8q^{36} - 12q^{38} - 8q^{39} + 4q^{43} + 32q^{48} - 24q^{51} - 8q^{52} + 18q^{53} - 8q^{55} + 16q^{61} + 24q^{62} + 32q^{64} - 6q^{65} - 16q^{66} - 24q^{68} + 24q^{69} - 24q^{74} + 16q^{75} - 48q^{78} + 18q^{79} + 22q^{81} + 40q^{82} + 12q^{87} - 8q^{90} + 24q^{92} - 44q^{94} - 6q^{95} + O(q^{100})$$
## Character values
We give the values of $$\chi$$ on generators for $$\left(\mathbb{Z}/637\mathbb{Z}\right)^\times$$.
$$n$$ $$197$$ $$248$$ $$\chi(n)$$ $$-1$$ $$-1 + \zeta_{12}^{2}$$
## Embeddings
For each embedding $$\iota_m$$ of the coefficient field, the values $$\iota_m(a_n)$$ are shown below.
For more information on an embedded modular form you can click on its label.
Label $$\iota_m(\nu)$$ $$a_{2}$$ $$a_{3}$$ $$a_{4}$$ $$a_{5}$$ $$a_{6}$$ $$a_{7}$$ $$a_{8}$$ $$a_{9}$$ $$a_{10}$$
116.1
−0.866025 + 0.500000i 0.866025 − 0.500000i −0.866025 − 0.500000i 0.866025 + 0.500000i
−1.73205 + 1.00000i 1.00000 1.73205i 1.00000 1.73205i −0.866025 + 0.500000i 4.00000i 0 0 −0.500000 0.866025i 1.00000 1.73205i
116.2 1.73205 1.00000i 1.00000 1.73205i 1.00000 1.73205i 0.866025 0.500000i 4.00000i 0 0 −0.500000 0.866025i 1.00000 1.73205i
324.1 −1.73205 1.00000i 1.00000 + 1.73205i 1.00000 + 1.73205i −0.866025 0.500000i 4.00000i 0 0 −0.500000 + 0.866025i 1.00000 + 1.73205i
324.2 1.73205 + 1.00000i 1.00000 + 1.73205i 1.00000 + 1.73205i 0.866025 + 0.500000i 4.00000i 0 0 −0.500000 + 0.866025i 1.00000 + 1.73205i
$$n$$: e.g. 2-40 or 990-1000 Significant digits: Format: Complex embeddings Normalized embeddings Satake parameters Satake angles
## Inner twists
Char Parity Ord Mult Type
1.a even 1 1 trivial
7.c even 3 1 inner
13.b even 2 1 inner
91.r even 6 1 inner
## Twists
By twisting character orbit
Char Parity Ord Mult Type Twist Min Dim
1.a even 1 1 trivial 637.2.r.c 4
7.b odd 2 1 637.2.r.a 4
7.c even 3 1 637.2.c.a 2
7.c even 3 1 inner 637.2.r.c 4
7.d odd 6 1 637.2.c.c yes 2
7.d odd 6 1 637.2.r.a 4
13.b even 2 1 inner 637.2.r.c 4
91.b odd 2 1 637.2.r.a 4
91.r even 6 1 637.2.c.a 2
91.r even 6 1 inner 637.2.r.c 4
91.s odd 6 1 637.2.c.c yes 2
91.s odd 6 1 637.2.r.a 4
91.z odd 12 1 8281.2.a.a 1
91.z odd 12 1 8281.2.a.k 1
91.bb even 12 1 8281.2.a.b 1
91.bb even 12 1 8281.2.a.m 1
By twisted newform orbit
Twist Min Dim Char Parity Ord Mult Type
637.2.c.a 2 7.c even 3 1
637.2.c.a 2 91.r even 6 1
637.2.c.c yes 2 7.d odd 6 1
637.2.c.c yes 2 91.s odd 6 1
637.2.r.a 4 7.b odd 2 1
637.2.r.a 4 7.d odd 6 1
637.2.r.a 4 91.b odd 2 1
637.2.r.a 4 91.s odd 6 1
637.2.r.c 4 1.a even 1 1 trivial
637.2.r.c 4 7.c even 3 1 inner
637.2.r.c 4 13.b even 2 1 inner
637.2.r.c 4 91.r even 6 1 inner
8281.2.a.a 1 91.z odd 12 1
8281.2.a.b 1 91.bb even 12 1
8281.2.a.k 1 91.z odd 12 1
8281.2.a.m 1 91.bb even 12 1
## Hecke kernels
This newform subspace can be constructed as the intersection of the kernels of the following linear operators acting on $$S_{2}^{\mathrm{new}}(637, [\chi])$$:
$$T_{2}^{4} - 4 T_{2}^{2} + 16$$ $$T_{3}^{2} - 2 T_{3} + 4$$
## Hecke characteristic polynomials
$p$ $F_p(T)$
$2$ $$16 - 4 T^{2} + T^{4}$$
$3$ $$( 4 - 2 T + T^{2} )^{2}$$
$5$ $$1 - T^{2} + T^{4}$$
$7$ $$T^{4}$$
$11$ $$16 - 4 T^{2} + T^{4}$$
$13$ $$( 13 + 4 T + T^{2} )^{2}$$
$17$ $$( 36 - 6 T + T^{2} )^{2}$$
$19$ $$81 - 9 T^{2} + T^{4}$$
$23$ $$( 9 - 3 T + T^{2} )^{2}$$
$29$ $$( -3 + T )^{4}$$
$31$ $$81 - 9 T^{2} + T^{4}$$
$37$ $$1296 - 36 T^{2} + T^{4}$$
$41$ $$( 100 + T^{2} )^{2}$$
$43$ $$( -1 + T )^{4}$$
$47$ $$14641 - 121 T^{2} + T^{4}$$
$53$ $$( 81 - 9 T + T^{2} )^{2}$$
$59$ $$4096 - 64 T^{2} + T^{4}$$
$61$ $$( 64 - 8 T + T^{2} )^{2}$$
$67$ $$20736 - 144 T^{2} + T^{4}$$
$71$ $$( 196 + T^{2} )^{2}$$
$73$ $$6561 - 81 T^{2} + T^{4}$$
$79$ $$( 81 - 9 T + T^{2} )^{2}$$
$83$ $$( 121 + T^{2} )^{2}$$
$89$ $$625 - 25 T^{2} + T^{4}$$
$97$ $$( 81 + T^{2} )^{2}$$ | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9951680302619934, "perplexity": 10632.621909745018}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323585450.39/warc/CC-MAIN-20211022021705-20211022051705-00000.warc.gz"} |
https://math.stackexchange.com/questions/946738/nice-question-in-mathmatics-about-times | Nice Question in Mathmatics about Times
I ran into a nice question from one book in Discrete Mathematics. I want to someone lean me how solve such a problem, because I prepare for entrance exam.
if the time is "Wednesday 4 afternoon", after $47^{74}$ hours, we are in what hours? and what day?
Thanks to all.
• I guess there's no daylight saving time in wherever that book was written. Even leap seconds ruin everything here, so those have to be ignored, too. – JiK Sep 26 '14 at 9:59
• In $47^{74}$ hours we will be in the grave. Whoever set that problem should have made at least a mild effort to keep the premise from being completely ridiculous. – KCd Sep 26 '14 at 12:19
If now it's “Wednesday, 4pm”, then $16$ hours ago it was “Wednesday, 0:00”.
Thus the problem is to know what hour it is $47^{74}+16$ hours after “Wed, 0:00”. This is obviously solved by computing the remainder of $47^{74}+16$ divided by $24$; since $47$ is coprime with $24$ and $\varphi(24)=8$, from Fermat-Euler we can say $$47^{8}\equiv 1\pmod{24}$$ hence $47^{74}\equiv 47^2=2209\equiv 1\pmod{24}$. Therefore, adding back $16$, we know that we'll be at 17:00, that is, 5pm.
In order to know what day it will be, compute the remainder of $47^{74}+16$ modulo $7\cdot 24$; recall that $\varphi(7\cdot24)=6\cdot 8=48$.
By Fermat-Euler, you need to compute the remainder of $$47^{74-48}=47^{26}=47^2\cdot47^8\cdot47^{16}$$ Now (all congruences are modulo $168$) \begin{align} 47^2&=2209\equiv25\\ 47^3&\equiv25\cdot47=1175\equiv167\equiv-1\\ \end{align} So $47^8=(47^3)^2\cdot47^2\equiv25$ and $47^{16}=(47^3)^5\cdot47\equiv-47\equiv121$.
Therefore $$47^{74}\equiv25\cdot25\cdot121=75625\equiv25\pmod{168}$$ and it's the same as $25+16$ hours passed from “Wed 0:00”: one full day plus one hour (as seen before).
• Dear @egreg, so you means two days later? 48 hours? – Mouna Mokhiab Sep 26 '14 at 9:58
• I think Thursday? would you please describe it? – Mouna Mokhiab Sep 26 '14 at 10:16
• @MounaMokhiab Using that remainder is the same as throwing out whole weeks, which are unimportant. The quotient of the remainder by $24$ will give you the number of days to add. – egreg Sep 26 '14 at 10:29
• I know it. but how calculate the remainder by 24? would u please learn me ? – Mouna Mokhiab Sep 26 '14 at 10:54
• Dear @Egreg. I confused. please let me know how many days should be add? – Mouna Mokhiab Sep 26 '14 at 11:54
Since $47^{74}$ hours is more than a googol ($10^{100}$) years, by all estimates, the sun will be long gone, and we won't have days anymore.
But if you ignore all that, you should try to reduce $47^{74} \pmod{168}$ (the number of hours in a week). | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 1, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5968827605247498, "perplexity": 602.7368188027336}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-10/segments/1614178358798.23/warc/CC-MAIN-20210227084805-20210227114805-00102.warc.gz"} |
http://server1.wikisky.org/starview?object_type=1&object_id=6597&object_name=11+Aqr&locale=EN | WIKISKY.ORG
Home Getting Started To Survive in the Universe News@Sky Astro Photo The Collection Forum Blog New! FAQ Press Login
# 11 Aqr (11 Aquarii)
Contents
### Images
DSS Images Other Images
### Related articles
The origin and chemical evolution of carbon in the Galactic thin and thick discs*In order to trace the origin and evolution of carbon in the Galacticdisc, we have determined carbon abundances in 51 nearby F and G dwarfstars. The sample is divided into two kinematically distinct subsampleswith 35 and 16 stars that are representative of the Galactic thin andthick discs, respectively. The analysis is based on spectral synthesisof the forbidden [CI] line at 872.7nm using spectra of very highresolution (R~ 220000) and high signal-to-noise ratio (S/N >~ 300)that were obtained with the Coudé Echelle Spectrograph (CES)spectrograph by the European Southern Observatory (ESO) 3.6-m telescopeat La Silla in Chile. We find that [C/Fe] versus [Fe/H] trends for thethin and thick discs are totally merged and flat for subsolarmetallicities. The thin disc that extends to higher metallicities thanthe thick disc shows a shallow decline in [C/Fe] from [Fe/H]~ 0 and upto [Fe/H]~+0.4. The [C/O] versus [O/H] trends are well separated betweenthe two discs (due to differences in the oxygen abundances) and bear agreat resemblance to the [Fe/O] versus [O/H] trends. Our interpretationof our abundance trends is that the sources that are responsible for thecarbon enrichment in the Galactic thin and thick discs have operated ona time-scale very similar to those that are responsible for the Fe and Yenrichment [i.e. SNIa and asymptotic giant branch (AGB) stars,respectively]. We further note that there exist other observational datain the literature that favour massive stars as the main sources forcarbon. In order to match our carbon trends, we believe that the carbonyields from massive stars then must be very dependent on metallicity forthe C, Fe and Y trends to be so finely tuned in the two discpopulations. Such metallicity-dependent yields are no longer supportedby the new stellar models in the recent literature. For the Galaxy, wehence conclude that the carbon enrichment at metallicities typical ofthe disc is mainly due to low- and intermediate-mass stars, whilemassive stars are still the main carbon contributor at low metallicities(halo and metal-poor thick disc). Infrared 3-4 μm Spectroscopic Investigations of a Large Sample of Nearby Ultraluminous Infrared GalaxiesWe present infrared L-band (3-4 μm) nuclear spectra of a large sampleof nearby ultraluminous infrared galaxies (ULIRGs). ULIRGs classifiedoptically as non-Seyfert galaxies (LINERs, H II regions, andunclassified) are our main targets. Using the 3.3 μm polycyclicaromatic hydrocarbon (PAH) emission and absorption features at 3.1 μmdue to ice-covered dust and at 3.4 μm produced by bare carbonaceousdust, we search for signatures of powerful AGNs deeply buried alongvirtually all lines of sight. The 3.3 μm PAH emission, the signaturesof starbursts, is detected in all but two non-Seyfert ULIRGs, but theestimated starburst magnitudes can account for only a small fraction ofthe infrared luminosities. Three LINER ULIRGs show spectra typical ofalmost pure buried AGNs, namely, strong absorption features with verysmall equivalent width PAH emission. Besides these three sources, 14LINER and three H II ULIRGs' nuclei show strong absorption featureswhose absolute optical depths suggest an energy source more centrallyconcentrated than the surrounding dust, such as a buried AGN. In total,17 out of 27 (63%) LINER and 3 out of 13 (23%) H II ULIRGs' nuclei showsome degree of evidence for powerful buried AGNs, suggesting thatpowerful buried AGNs may be more common in LINER ULIRGs than in H IIULIRGs. The evidence of AGNs is found in non-Seyfert ULIRGs with bothwarm and cool far-infrared colors. These spectra are compared with thoseof 15 ULIRGs' nuclei with optical Seyfert signatures taken forcomparison. The overall spectral properties suggest that the totalamount of dust around buried AGNs in non-Seyfert ULIRGs issystematically larger than that around AGNs in Seyfert 2 ULIRGs. Weargue that the optical (non)detectability of Seyfert signatures inULIRGs is highly dependent on how deeply buried the AGNs are, and thatit is essential to properly evaluate the energetic importance of buriedAGNs in non-Seyfert ULIRGs. Lithium Abundances of F-, G-, and K-Type Stars: Profile-Fitting Analysis of the Li I 6708 DoubletAn extensive profile-fitting analysis was performed for the Li(+Fe)6707-6708Å feature of nearby 160 F-K dwarfs/subgiants (including27 planet-host stars) in the Galactic disk ( 7000 K ≳Teff ≳ 5000 K, -1 ≲ [Fe/H] ≲ +0.4), in orderto establish the photospheric lithium abundances of these stars. Thenon-LTE effect (though quantitatively insignificant) was taken intoaccount based on our statistical equilibrium calculations, which werecarried out on an adequate grid of models. Our results confirmed most ofthe interesting observational characteristics revealed by recentlypublished studies, such as the bimodal distribution of the Li abundancesfor stars at Teff ≳ 6000 K, the satisfactory agreementof the upper envelope of the A(Li) vs. [Fe/H] distribution with thetheoretical models, the existence of a positive correlation betweenA(Li) and the stellar mass, and the tendency of lower lithium abundancesof planet-host stars (as compared to stars without planets) at thenarrow transition'' region of 5900 K ≳ Teff ≳5800 K. The solar Li abundance derived from this analysis is 0.92 (H =12.00), which is by 0.24dex lower than the widely referenced standardvalue of 1.16. Spectroscopic Study on the Atmospheric Parameters of Nearby F--K Dwarfs and SubgiantsBased on a collection of high-dispersion spectra obtained at OkayamaAstrophysical Observatory, the atmospheric parameters (Teff,log g, vt, and [Fe/H]) of 160 mid-F through early-K starswere extensively determined by the spectroscopic method using theequivalent widths of Fe I and Fe II lines along with the numericaltechnique of Takeda et al. (2002, PASJ, 54, 451). The results arecomprehensively discussed and compared with the parameter values derivedby different approaches (e.g., photometric colors, theoreticalevolutionary tracks, Hipparcos parallaxes, etc.) as well as with thepublished values found in various literature. It has been confirmed thatour purely spectroscopic approach yields fairly reliable and consistentresults. Spectroscopic Properties of Cool Stars (SPOCS). I. 1040 F, G, and K Dwarfs from Keck, Lick, and AAT Planet Search ProgramsWe present a uniform catalog of stellar properties for 1040 nearby F, G,and K stars that have been observed by the Keck, Lick, and AAT planetsearch programs. Fitting observed echelle spectra with synthetic spectrayielded effective temperature, surface gravity, metallicity, projectedrotational velocity, and abundances of the elements Na, Si, Ti, Fe, andNi, for every star in the catalog. Combining V-band photometry andHipparcos parallaxes with a bolometric correction based on thespectroscopic results yielded stellar luminosity, radius, and mass.Interpolating Yonsei-Yale isochrones to the luminosity, effectivetemperature, metallicity, and α-element enhancement of each staryielded a theoretical mass, radius, gravity, and age range for moststars in the catalog. Automated tools provide uniform results and makeanalysis of such a large sample practical. Our analysis method differsfrom traditional abundance analyses in that we fit the observed spectrumdirectly, rather than trying to match equivalent widths, and wedetermine effective temperature and surface gravity from the spectrumitself, rather than adopting values based on measured photometry orparallax. As part of our analysis, we determined a new relationshipbetween macroturbulence and effective temperature on the main sequence.Detailed error analysis revealed small systematic offsets with respectto the Sun and spurious abundance trends as a function of effectivetemperature that would be inobvious in smaller samples. We attempted toremove these errors by applying empirical corrections, achieving aprecision per spectrum of 44 K in effective temperature, 0.03 dex inmetallicity, 0.06 dex in the logarithm of gravity, and 0.5 kms-1 in projected rotational velocity. Comparisons withprevious studies show only small discrepancies. Our spectroscopicallydetermined masses have a median fractional precision of 15%, but theyare systematically 10% higher than masses obtained by interpolatingisochrones. Our spectroscopic radii have a median fractional precisionof 3%. Our ages from isochrones have a precision that variesdramatically with location in the Hertzsprung-Russell diagram. We planto extend the catalog by applying our automated analysis technique toother large stellar samples. The Planet-Metallicity CorrelationWe have recently carried out spectral synthesis modeling to determineTeff, logg, vsini, and [Fe/H] for 1040 FGK-type stars on theKeck, Lick, and Anglo-Australian Telescope planet search programs. Thisis the first time that a single, uniform spectroscopic analysis has beenmade for every star on a large Doppler planet search survey. We identifya subset of 850 stars that have Doppler observations sufficient todetect uniformly all planets with radial velocity semiamplitudes K>30m s-1 and orbital periods shorter than 4 yr. From this subsetof stars, we determine that fewer than 3% of stars with-0.5<[Fe/H]<0.0 have Doppler-detected planets. Above solarmetallicity, there is a smooth and rapid rise in the fraction of starswith planets. At [Fe/H]>+0.3 dex, 25% of observed stars have detectedgas giant planets. A power-law fit to these data relates the formationprobability for gas giant planets to the square of the number of metalatoms. High stellar metallicity also appears to be correlated with thepresence of multiple-planet systems and with the total detected planetmass. This data set was examined to better understand the origin of highmetallicity in stars with planets. None of the expected fossilsignatures of accretion are observed in stars with planets relative tothe general sample: (1) metallicity does not appear to increase as themass of the convective envelopes decreases, (2) subgiants with planetsdo not show dilution of metallicity, (3) no abundance variations for Na,Si, Ti, or Ni are found as a function of condensation temperature, and(4) no correlations between metallicity and orbital period oreccentricity could be identified. We conclude that stars with extrasolarplanets do not have an accretion signature that distinguishes them fromother stars; more likely, they are simply born in higher metallicitymolecular clouds.Based on observations obtained at Lick and Keck Observatories, operatedby the University of California, and the Anglo-Australian Observatories. Abundance trends in kinematical groups of the Milky Way's diskWe have compiled a large catalogue of metallicities and abundance ratiosfrom the literature in order to investigate abundance trends of severalalpha and iron peak elements in the thin disk and the thick disk of theGalaxy. The catalogue includes 743 stars with abundances of Fe, O, Mg,Ca, Ti, Si, Na, Ni and Al in the metallicity range -1.30 < [Fe/H]< +0.50. We have checked that systematic differences betweenabundances measured in the different studies were lower than randomerrors before combining them. Accurate distances and proper motions fromHipparcos and radial velocities from several sources have been retreivedfor 639 stars and their velocities (U, V, W) and galactic orbits havebeen computed. Ages of 322 stars have been estimated with a Bayesianmethod of isochrone fitting. Two samples kinematically representative ofthe thin and thick disks have been selected, taking into account theHercules stream which is intermediate in kinematics, but with a probabledynamical origin. Our results show that the two disks are chemicallywell separated, they overlap greatly in metallicity and both showparallel decreasing alpha elements with increasing metallicity, in theinterval -0.80 < [Fe/H] < -0.30. The Mg enhancement with respectto Fe of the thick disk is measured to be 0.14 dex. An even largerenhancement is observed for Al. The thick disk is clearly older than thethin disk with tentative evidence of an AMR over 2-3 Gyr and a hiatus instar formation before the formation of the thin disk. We do not observea vertical gradient in the metallicity of the thick disk. The Herculesstream has properties similar to that of the thin disk, with a widerrange of metallicity. Metal-rich stars assigned to the thick disk andsuper-metal-rich stars assigned to the thin disk appear as outliers inall their properties. α-, r-, and s-process element trends in the Galactic thin and thick disksFrom a detailed elemental abundance analysis of 102 F and G dwarf starswe present abundance trends in the Galactic thin and thick disks for 14elements (O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, Y, Ba, and Eu).Stellar parameters and elemental abundances (except for Y, Ba and Eu)for 66 of the 102 stars were presented in our previous studies (Bensbyet al. [CITE], A&A, 410, 527, [CITE], A&A, 415, 155). The 36stars that are new in this study extend and confirm our previous resultsand allow us to draw further conclusions regarding abundance trends. Thes-process elements Y and Ba, and the r-element Eu have also beenconsidered here for the whole sample for the first time. With this newlarger sample we now have the following results: 1) smooth and distinctabundance trends that for the thin and thick disks are clearlyseparated; 2) the α-element trends for the thick disk show typicalsignatures from the enrichment of SN Ia; 3) the thick disk stellarsample is in the mean older than the thin disk stellar sample; 4) thethick disk abundance trends are invariant with galactocentric radii(R_m); 5) the thick disk abundance trends appear to be invariant withvertical distance (Z_max) from the Galactic plane. Adding furtherevidence from the literaure we argue that a merger/interacting scenariowith a companion galaxy to produce a kinematical heating of the stars(that make up today's thick disk) in a pre-existing old thin disk is themost likely formation scenario for the Galactic thick disk. The 102stars have -1 ≲ [Fe/H] ≲ +0.4 and are all in the solarneighbourhood. Based on their kinematics they have been divided into athin disk sample and a thick disk sample consisting of 60 and 38 stars,respectively. The remaining 4 stars have kinematics that make themkinematically intermediate to the two disks. Their chemical abundancesalso place them in between the two disks. Which of the two diskpopulations these 4 stars belong to, or if they form a distinctpopulation of their own, can at the moment not be settled. The 66 starsfrom our previous studies were observed with the FEROS spectrograph onthe ESO 1.5-m telescope and the CES spectrograph on the ESO 3.6-mtelescope. Of the 36 new stars presented here 30 were observed with theSOFIN spectrograph on the Nordic Optical Telescope on La Palma, 3 withthe UVES spectrograph on VLT/UT2, and 3 with the FEROS spectrograph onthe ESO 1.5-m telescope. All spectra have high signal-to-noise ratios(typically S/N≳ 250) and high resolution (R 80 000, 45 000,and 110 000 for the SOFIN, FEROS, and UVES spectra, respectively).Based on observations collected at the Nordic Optical Telescope on LaPalma, Spain, and at the European Southern Observatories on La Silla andParanal, Chile, Proposals # 65.L-0019(B), 67.B-0108(B), 69.B-0277. FullTables [see full text], [see full text] and [see full text] are onlyavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/433/185 Isochrone ages for field dwarfs: method and application to the age-metallicity relation A new method is presented to compute age estimates from theoreticalisochrones using temperature, luminosity and metallicity data forindividual stars. Based on Bayesian probability theory, this methodavoids the systematic biases affecting simpler strategies and providesreliable estimates of the age probability distribution function forlate-type dwarfs. Basic assumptions concerning the a priori parameterdistribution suitable for the solar neighbourhood are combined with thelikelihood assigned to the observed data to yield the complete posteriorage probability. This method is especially relevant for G dwarfs in the3-15 Gyr range of ages, crucial to the study of the chemical anddynamical history of the Galaxy. In many cases, it yields markedlydifferent results from the traditional approach of reading the derivedage from the isochrone nearest to the data point. We show that thestrongest process affecting the traditional approach is that of stronglyfavouring computed ages near the end-of-main-sequence lifetime. TheBayesian method compensates for this potential bias and generallyassigns much higher probabilities to lower main-sequence ages, comparedwith short-lived evolved stages. This has a strong influence on anyapplication to galactic studies, especially given the presentuncertainties on the absolute temperature scale of the stellar evolutionmodels. In particular, the known mismatch between the model predictionsand the observations for moderately metal-poor dwarfs (-1 < [Fe/H]< -0.3) has a dramatic effect on the traditional age determination.We apply our method to the classic sample of Edvardsson et al., whoderived the age-metallicity relation (AMR) of 189 field dwarfs withprecisely determined abundances. We show how much of the observedscatter in the AMR is caused by the interplay between the systematicbiases affecting the traditional age determination, the colour mismatchwith the evolution models and the presence of undetected binaries. Usingnew parallax, temperature and metallicity data, our age determinationfor the same sample indicates that the intrinsic dispersion in the AMRis at most 0.15 dex and probably lower. In particular, we show that old,metal-rich objects ([Fe/H]~ 0.0 dex, age > 5 Gyr) and young,metal-poor objects ([Fe/H] < -0.5 dex, age < 6 Gyr) in manyobserved AMR plots are artefacts caused by too simple a treatment of theage determination. The incompatibility of those AMR plots with awell-mixed interstellar medium may therefore only be apparent.Incidentally, our results tend to restore confidence in the method ofage determination from the chromospheric activity for field dwarfs. Lithium abundances of the local thin disc starsLithium abundances are presented for a sample of 181 nearby F and Gdwarfs with accurate Hipparcos parallaxes. The stars are on circularorbits about the Galactic centre and, hence, are identified as belongingto the thin disc. This sample is combined with two published surveys toprovide a catalogue of lithium abundances, metallicities ([Fe/H]),masses, and ages for 451 F-G dwarfs, almost all belonging to the thindisc. The lithium abundances are compared and contrasted with publishedlithium abundances for F and G stars in local open clusters. The fieldstars span a larger range in [Fe/H] than the clusters for which [Fe/H]~=0.0 +/- 0.2. The initial (i.e. interstellar) lithium abundance of thesolar neighbourhood, as derived from stars for which astration oflithium is believed to be unimportant, is traced from logɛ(Li) =2.2 at [Fe/H]=-1 to logɛ(Li) = 3.2 at +0.1. This form for theevolution is dependent on the assumption that astration of lithium isnegligible for the stars defining the relation. An argument is advancedthat this latter assumption may not be entirely correct, and, theevolution of lithium with [Fe/H] may be flatter than previouslysupposed. A sharp Hyades-like Li dip is not seen among the field starsand appears to be replaced by a large spread among lithium abundances ofstars more massive than the lower mass limit of the dip. Astration oflithium by stars of masses too low to participate in the Li dip isdiscussed. These stars show little to no spread in lithium abundance ata given [Fe/H] and mass. Chromospheric Ca II Emission in Nearby F, G, K, and M StarsWe present chromospheric Ca II H and K activity measurements, rotationperiods, and ages for ~1200 F, G, K, and M type main-sequence stars from~18,000 archival spectra taken at Keck and Lick Observatories as a partof the California and Carnegie Planet Search Project. We have calibratedour chromospheric S-values against the Mount Wilson chromosphericactivity data. From these measurements we have calculated medianactivity levels and derived R'HK, stellar ages,and rotation periods from general parameterizations for 1228 stars,~1000 of which have no previously published S-values. We also presentprecise time series of activity measurements for these stars.Based on observations obtained at Lick Observatory, which is operated bythe University of California, and on observations obtained at the W. M.Keck Observatory, which is operated jointly by the University ofCalifornia and the California Institute of Technology. The KeckObservatory was made possible by the generous financial support of theW. M. Keck Foundation. The Indo-US Library of Coudé Feed Stellar SpectraWe have obtained spectra for 1273 stars using the 0.9 m coudéfeed telescope at Kitt Peak National Observatory. This telescope feedsthe coudé spectrograph of the 2.1 m telescope. The spectra havebeen obtained with the no. 5 camera of the coudé spectrograph anda Loral 3K×1K CCD. Two gratings have been used to provide spectralcoverage from 3460 to 9464 Å, at a resolution of ~1 Å FWHMand at an original dispersion of 0.44 Å pixel-1. For885 stars we have complete spectra over the entire 3460 to 9464 Åwavelength region (neglecting small gaps of less than 50 Å), andpartial spectral coverage for the remaining stars. The 1273 stars havebeen selected to provide broad coverage of the atmospheric parametersTeff, logg, and [Fe/H], as well as spectral type. The goal ofthe project is to provide a comprehensive library of stellar spectra foruse in the automated classification of stellar and galaxy spectra and ingalaxy population synthesis. In this paper we discuss thecharacteristics of the spectral library, viz., details of theobservations, data reduction procedures, and selection of stars. We alsopresent a few illustrations of the quality and information available inthe spectra. The first version of the complete spectral library is nowpublicly available from the National Optical Astronomy Observatory(NOAO) via ftp and http. The Correlation of Lithium and Beryllium in F and G Field and Cluster Dwarf StarsAlthough Li has been extensively observed in main-sequence field andcluster stars, there are relatively fewer observations of Be. We haveobtained Keck HIRES spectra of 36 late F and early G dwarfs in order tostudy the Li-Be correlation we found previously in the temperatureregime of 5900-6650 K. The sample size for this temperature range withdetectable and (usually) depleted Li and Be is now 88, including Li andBe abundances in both cluster and field stars. Therefore we can nowinvestigate the influence of other parameters such as age, temperature,and metallicity on the correlation. The Be spectra at 3130 Å weretaken over six nights from 1999 November to 2002 January and have aspectral resolution of ~48,000 and a median signal-to-noise ratio (S/N)of 108 pixel-1. We obtained Li spectra of 22 stars with theUniversity of Hawaii 88 inch (2.2 m) telescope and coudéspectrograph with a spectral resolution of ~70,000 and a median S/N of110 pixel-1. We have redetermined the effective temperaturesfor all the stars and adopted other parameters from published data orempirical relations. The abundances of both Li and Be in the stars weobserved were determined from spectrum synthesis with MOOG 2002. Thepreviously observed Li equivalent widths for some of our Be stars wereused with the new temperatures and MOOG 2002 in the blends'' mode. Forthe 46 field stars from this and earlier studies we find a linearrelation between A(Li) and A(Be) with a slope of 0.375+/-0.036. Over theTeff range 5900-6650 K, we find the modest scatter about theBe-Li relation to be significantly correlated with Teff andperhaps also [Fe/H]. Dividing the sample into two temperature regimes of6300-6650 K (corresponding to the cool side of the Li-Be dip) and5900-6300 K (corresponding to the Li plateau'') reveals possible smalldifferences in the slopes for the two groups, 0.404+/-0.034 and0.365+/-0.049, respectively. When we include the cluster stars (Hyades,Pleiades, Praesepe, UMa Group, and Coma), the slope for the fulltemperature range (88 stars) is essentially the same, at 0.382+/-0.030,as for the field stars alone. For the hotter temperature group of 35Li-Be dip stars in the field and in clusters the slope is higher, at0.433+/-0.036, while for the cooler star group (54 stars) the slope is0.337+/-0.031, different by more than 1 σ. This small differencein the slope is predicted by the theory of rotationally induced mixing.The four stars with [Fe/H] less than -0.4 are all below the best-fitrelation, i.e., there is more Be depletion at a given A(Li) or less Beab initio. The youngest stars, i.e., Pleiades, have less depletion ofboth Li and Be. This too is predicted by rotationally induced slowmixing. Combining the Be results from both field and cluster stars, wefind that there are stars with undepleted Be, i.e., near the meteoriticvalues of 1.42 dex, at all temperatures from 5500 to 6800 K. Depletionsof Be of up to and even exceeding 2 orders of magnitude are commonbetween 6000 and 6700 K. Synthetic Lick Indices and Detection of α-enhanced Stars. II. F, G, and K Stars in the -1.0 < [Fe/H] < +0.50 RangeWe present an analysis of 402 F, G, and K solar neighborhood stars, withaccurate estimates of [Fe/H] in the range -1.0 to +0.5 dex, aimed at thedetection of α-enhanced stars and at the investigation of theirkinematical properties. The analysis is based on the comparison of 571sets of spectral indices in the Lick/IDS system, coming from fourdifferent observational data sets, with synthetic indices computed withsolar-scaled abundances and with α-element enhancement. We useselected combinations of indices to single out α-enhanced starswithout requiring previous knowledge of their main atmosphericparameters. By applying this approach to the total data set, we obtain alist of 60 bona fide α-enhanced stars and of 146 stars withsolar-scaled abundances. The properties of the detected α-enhancedand solar-scaled abundance stars with respect to their [Fe/H] values andkinematics are presented. A clear kinematic distinction betweensolar-scaled and α-enhanced stars was found, although a one-to-onecorrespondence to thin disk'' and thick disk'' components cannot besupported with the present data. Stellar Chemical Signatures and Hierarchical Galaxy FormationTo compare the chemistries of stars in the Milky Way dwarf spheroidal(dSph) satellite galaxies with stars in the Galaxy, we have compiled alarge sample of Galactic stellar abundances from the literature. Whenkinematic information is available, we have assigned the stars tostandard Galactic components through Bayesian classification based onGaussian velocity ellipsoids. As found in previous studies, the[α/Fe] ratios of most stars in the dSph galaxies are generallylower than similar metallicity Galactic stars in this extended sample.Our kinematically selected stars confirm this for the Galactic halo,thin-disk, and thick-disk components. There is marginal overlap in thelow [α/Fe] ratios between dSph stars and Galactic halo stars onextreme retrograde orbits (V<-420 km s-1), but this is notsupported by other element ratios. Other element ratios compared in thispaper include r- and s-process abundances, where we find a significantoffset in the [Y/Fe] ratios, which results in a large overabundance in[Ba/Y] in most dSph stars compared with Galactic stars. Thus, thechemical signatures of most of the dSph stars are distinct from thestars in each of the kinematic components of the Galaxy. This resultrules out continuous merging of low-mass galaxies similar to these dSphsatellites during the formation of the Galaxy. However, we do not ruleout very early merging of low-mass dwarf galaxies, since up to one-halfof the most metal-poor stars ([Fe/H]<=-1.8) have chemistries that arein fair agreement with Galactic halo stars. We also do not rule outmerging with higher mass galaxies, although we note that the LMC and theremnants of the Sgr dwarf galaxy are also chemically distinct from themajority of the Galactic halo stars. Formation of the Galaxy's thickdisk by heating of an old thin disk during a merger is also not ruledout; however, the Galaxy's thick disk itself cannot be comprised of theremnants from a low-mass (dSph) dwarf galaxy, nor of a high-mass dwarfgalaxy like the LMC or Sgr, because of differences in chemistry.The new and independent environments offered by the dSph galaxies alsoallow us to examine fundamental assumptions related to thenucleosynthesis of the elements. The metal-poor stars ([Fe/H]<=-1.8)in the dSph galaxies appear to have lower [Ca/Fe] and [Ti/Fe] than[Mg/Fe] ratios, unlike similar metallicity stars in the Galaxy.Predictions from the α-process (α-rich freeze-out) would beconsistent with this result if there have been a lack of hypernovae indSph galaxies. The α-process could also be responsible for thevery low Y abundances in the metal-poor stars in dSph's; since [La/Eu](and possibly [Ba/Eu]) are consistent with pure r-process results, thelow [Y/Eu] suggests a separate r-process site for this light(first-peak) r-process element. We also discuss SNe II rates and yieldsas other alternatives, however. In stars with higher metallicities([Fe/H]>=-1.8), contributions from the s-process are expected; [(Y,La, and Ba)/Eu] all rise as expected, and yet [Ba/Y] is still muchhigher in the dSph stars than similar metallicity Galactic stars. Thisresult is consistent with s-process contributions from lower metallicityAGB stars in dSph galaxies, and is in good agreement with the slowerchemical evolution expected in the low-mass dSph galaxies relative tothe Galaxy, such that the build-up of metals occurs over much longertimescales. Future investigations of nucleosynthetic constraints (aswell as galaxy formation and evolution) will require an examination ofmany stars within individual dwarf galaxies.Finally, the Na-Ni trend reported in 1997 by Nissen & Schuster isconfirmed in Galactic halo stars, but we discuss this in terms of thegeneral nucleosynthesis of neutron-rich elements. We do not confirm thatthe Na-Ni trend is related to the accretion of dSph galaxies in theGalactic halo. A new Böhm-Vitense gap in the temperature range 5560 to 5610 K in the main sequence hm-Vitense gap in the main sequenceHighly precise temperatures (σ = 10-15 K) have been determinedfrom line depth ratios for a set of 248 F-K field dwarfs of about solarmetallicity (-0.5 < [Fe/H] < +0.4), based on high resolution (R=42000), high S/N echelle spectra. A new gap has been discovered in thedistribution of stars on the Main Sequence in the temperature range 5560to 5610 K. This gap coincides with a jump in the microturbulent velocityVt and the well-known Li depression near 5600 K in fielddwarfs and open clusters. As the principal cause of the observeddiscontinuities in stellar properties we propose the penetration of theconvective zone into the inner layers of stars slightly less massivethan the Sun and related to it, a change in the temperature gradient.Based on spectra collected with the ELODIE spectrograph at the 1.93-mtelescope of the Observatoire de Haute-Provence (France).Full Table 1 is only available in electronic form athttp://www.edpsciences.org On the determination of oxygen abundances in chromospherically active starsWe discuss oxygen abundances derived from [O I] λ6300s and the OI triplet in stars spanning a wide range in chromospheric activitylevel, and show that these two indicators yield increasingly discrepantresults with higher chromospheric/coronal activity measures. While theforbidden and permitted lines give fairly consistent results forsolar-type disk dwarfs, spuriously high O I triplet abundances areobserved in young Hyades and Pleiades stars, as well as in individualcomponents of RS CVn binaries (up to 1.8 dex). The distinct behaviour ofthe [O I]-based abundances which consistently remain near-solar suggeststhat this phenomenon mostly results from large departures from LTEaffecting the O I triplet at high activity level that are currentlyunaccounted for, but also possibly from a failure to adequately modelthe atmospheres of K-type stars. These results suggest that some cautionshould be exercised when interpreting oxygen abundances in activebinaries or young open cluster stars.Based on observations collected at the European Southern Observatory,Chile (Proposals 64.L-0249 and 071.D-0260).Table \ref{tab_data} is only available in electronic form athttp://www.edpsciences.org The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of 14 000 F and G dwarfsWe present and discuss new determinations of metallicity, rotation, age,kinematics, and Galactic orbits for a complete, magnitude-limited, andkinematically unbiased sample of 16 682 nearby F and G dwarf stars. Our63 000 new, accurate radial-velocity observations for nearly 13 500stars allow identification of most of the binary stars in the sampleand, together with published uvbyβ photometry, Hipparcosparallaxes, Tycho-2 proper motions, and a few earlier radial velocities,complete the kinematic information for 14 139 stars. These high-qualityvelocity data are supplemented by effective temperatures andmetallicities newly derived from recent and/or revised calibrations. Theremaining stars either lack Hipparcos data or have fast rotation. Amajor effort has been devoted to the determination of new isochrone agesfor all stars for which this is possible. Particular attention has beengiven to a realistic treatment of statistical biases and errorestimates, as standard techniques tend to underestimate these effectsand introduce spurious features in the age distributions. Our ages agreewell with those by Edvardsson et al. (\cite{edv93}), despite severalastrophysical and computational improvements since then. We demonstrate,however, how strong observational and theoretical biases cause thedistribution of the observed ages to be very different from that of thetrue age distribution of the sample. Among the many basic relations ofthe Galactic disk that can be reinvestigated from the data presentedhere, we revisit the metallicity distribution of the G dwarfs and theage-metallicity, age-velocity, and metallicity-velocity relations of theSolar neighbourhood. Our first results confirm the lack of metal-poor Gdwarfs relative to closed-box model predictions (the G dwarfproblem''), the existence of radial metallicity gradients in the disk,the small change in mean metallicity of the thin disk since itsformation and the substantial scatter in metallicity at all ages, andthe continuing kinematic heating of the thin disk with an efficiencyconsistent with that expected for a combination of spiral arms and giantmolecular clouds. Distinct features in the distribution of the Vcomponent of the space motion are extended in age and metallicity,corresponding to the effects of stochastic spiral waves rather thanclassical moving groups, and may complicate the identification ofthick-disk stars from kinematic criteria. More advanced analyses of thisrich material will require careful simulations of the selection criteriafor the sample and the distribution of observational errors.Based on observations made with the Danish 1.5-m telescope at ESO, LaSilla, Chile, and with the Swiss 1-m telescope at Observatoire deHaute-Provence, France.Complete Tables 1 and 2 are only available in electronic form at the CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/418/989 On the correlation of elemental abundances with kinematics among galactic disk starsWe have performed the detailed analysis of 174 high-resolution spectraof FGK dwarfs obtained with the ELODIE echelle spectrograph at theObservatoire de Haute-Provence. Abundances of Fe, Si and Ni have beendetermined from equivalent widths under LTE approximation, whereasabundances of Mg have been determined under NLTE approximation usingequivalent widths of 4 lines and profiles of 5 lines. Spatial velocitieswith an accuracy better than 1 km s-1, as well as orbits,have been computed for all stars. They have been used to define 2subsamples kinematically representative of the thin disk and the thickdisk in order to highlight their respective properties. A transitionoccurs at [Fe/H] =-0.3. Stars more metal-rich than this value have aflat distribution with Zmax;<1 kpc and σW<20 km s-1, and a narrow distribution of [α/Fe].There exist stars in this metallicity regime which cannot belong to thethin disk because of their excentric orbits, neither to the thick diskbecause of their low scale height. Several thin disk stars areidentified down to [Fe/H] =-0.80. Their Mg enrichment is lower thanthick disk stars with the same metallicity. We confirm from a largersample the results of Feltzing et al. (\cite{felt03}) and Bensby et al.(\cite{ben03}) showing a decrease of [α/Fe] with [Fe/H] in thethick disk interpreted as the signature of the SNIa which haveprogressively enriched the ISM with iron. However our data suggest thatthe star formation in the thick disk stopped when the enrichment was[Fe/H] =-0.30, [Mg/Fe] =+0.20, [Si/Fe] =+0.17. A vertical gradient in[α/Fe] may exist in the thick disk but should be confirmed with alarger sample. Finally we have identified 2 new candidates of the HR1614moving group.Based on spectra collected with the ELODIE spectrograph at the 1.93-mtelescope of the Observatoire de Haute Provence (France).Tables 3 and 8 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/418/551 Oxygen trends in the Galactic thin and thick disksWe present oxygen abundances for 72 F and G dwarf stars in the solarneighbourhood. Using the kinematics of the stars we divide them into twosub-samples with space velocities that are typical for the thick andthin disks, respectively. The metallicities of the stars range from[Fe/H] ≈ -0.9 to +0.4 and we use the derived oxygen abundances of thestars to: (1) perform a differential study of the oxygen trends in thethin and the thick disk; (2) to follow the trend of oxygen in the thindisk to the highest metallicities. We analyze the forbidden oxygen linesat 6300 Å and 6363 Å as well as the (NLTE afflicted) tripletlines around 7774 Å. For the forbidden line at 6300 Å wehave spectra of very high S/N (>400) and resolution (R ≳ 215000). This has enabled a very accurate modeling of the oxygen line andthe blending Ni lines. The high internal accuracy in our determinationof the oxygen abundances from this line is reflected in the very tighttrends we find for oxygen relative to iron. From these abundances we areable to draw the following major conclusions: (i) That the [O/Fe] trendat super-solar [Fe/H] continues downward which is in concordance withmodels of Galactic chemical evolution. This is not seen in previousstudies as it has not been possible to take the blending Ni lines in theforbidden oxygen line at 6300 Å properly into account; (ii) Thatthe oxygen trends in the thin and the thick disks are distinctlydifferent. This confirms and extends previous studies of the otherα-elements; (iii) That oxygen does not follow Mg at super-solarmetallicities; (iv) We also provide an empirical NLTE correction for theinfrared O I triplet that could be used for dwarf star spectra with aS/N such that only the triplet lines can be analyzed well, e.g. stars atlarge distances; (v) Finally, we find that Gratton et al. (1999)overestimate the NLTE corrections for the permitted oxygen triplet linesat 7774 Å for the parameter space that our stars span.Based on observations collected at the European Southern Observatory, LaSilla and Paranal, Chile, Proposals #65.L-0019, 67.B-0108, and69.B-0277.The full Table 4 is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?/A+A/415/155 Observational Constraints on Potassium Synthesis During the Formation of Stars of the Galactic DiskThe non-LTE potassium abundances in the atmospheres of 33 Galactic-diskstars are derived and the parameters of the atmospheres of 23 of thestars are determined. Neglecting departures from LTE results in asystematic overestimation of the potassium abundances and an increase intheir dispersion, even for differential analyses relative to the Sun.The non-LTE corrections are significant ((-0.2) (-0.6) dex) and dependon the surface gravities and effective temperatures of the stars. Themean potassium abundance for a sample of ten stars with [Fe/H]0.0is in agreement with the solar and meteoritic abundances (log ɛȯ(K)=5.12). As the stellar metallicity increases from [Fe/H]=(-1.0)to (0.2) dex, the [K/Fe] ratio decreases systematically from 0.3 dex to-0.1 dex. The derived dependence [K/Fe]-[Fe/H] is in agreement with theresults of published model calculations of the chemical evolution of theGalaxy. This indicates the dominance of explosive oxygen burning inmassive type II supernovae during the synthesis of potassium in theGalactic disk. Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I.We have embarked on a project, under the aegis of the Nearby Stars(NStars)/Space Interferometry Mission Preparatory Science Program, toobtain spectra, spectral types, and, where feasible, basic physicalparameters for the 3600 dwarf and giant stars earlier than M0 within 40pc of the Sun. In this paper, we report on the results of this projectfor the first 664 stars in the northern hemisphere. These resultsinclude precise, homogeneous spectral types, basic physical parameters(including the effective temperature, surface gravity, and overallmetallicity [M/H]), and measures of the chromospheric activity of ourprogram stars. Observed and derived data presented in this paper arealso available on the project's Web site. Elemental abundance trends in the Galactic thin and thick disks as traced by nearby F and G dwarf starsBased on spectra from F and G dwarf stars, we present elementalabundance trends in the Galactic thin and thick disks in the metallicityregime -0.8< [Fe/H] < +0.4. Our findings can besummarized as follows. 1) Both the thin and the thick disks show smoothand distinct abundance trends that, at sub-solar metallicities, areclearly separated. 2) For the alpha -elements the thick disk showssignatures of chemical enrichment from SNe type Ia. 3) The age of thethick disk sample is in the mean older than the thin disk sample. 4)Kinematically, there exist thick disk stars with super-solarmetallicities. Based on these findings, together with other constraintsfrom the literature, we discuss different formation scenarios for thethick disk. We suggest that the currently most likely formation scenariois a violent merger event or a close encounter with a companion galaxy.Based on kinematics the stellar sample was selected to contain starswith high probabilities of belonging either to the thin or to the thickGalactic disk. The total number of stars are 66 of which 21 belong tothe thick disk and 45 to the thin disk. The analysis is based onhigh-resolution spectra with high signal-to-noise (R ~ 48 000 and S/Ngtrsim 150, respectively) recorded with the FEROS spectrograph on LaSilla, Chile. Abundances have been determined for four alpha -elements(Mg, Si, Ca, and Ti), for four even-nuclei iron peak elements (Cr, Fe,Ni, and Zn), and for the light elements Na and Al, from equivalent widthmeasurements of ~ 30 000 spectral lines. An extensive investigation ofthe atomic parameters, log gf-values in particular, have been performedin order to achieve abundances that are trustworthy. Noteworthy is thatwe find for Ti good agreement between the abundances from Ti I and TiIi. Our solar Ti abundances are in concordance with the standardmeteoritic Ti abundanceBased on observations collected at the European Southern Observatory, LaSilla, Chile, Proposals #65.L-0019(B) and 67.B-0108(B).Full Tables \ref{tab:linelist} and \ref{tab:abundances} are onlyavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/410/527 Interrelations between V il and S tr photometric systems: The luminosity indicator (v - X)Using the largest database of near-IR Ca II Triplet indices currentlyavailable (Cenarro et al. \cite{Cenarro01a},b), we confirm our findingabout the influence of the Ca II stellar lines on the X magnitude ofthe Vilnius photometric system. This effect is significant for spectralsub-classes from early F until mid K. For this spectral range there is alinear relation between the v-X index and the strength of the infraredCa II Triplet, which implies that the Ca II H&K lines shouldinfluence the difference in a similar way. For the spectral intervalstudied, v-X repeats the behavior of the Ca II Triplet with respect togravity, temperature and metallicity. The Ca II Triplet lines are apowerful diagnostic of the stellar populations in galaxies because oftheir sensitivity to the main stellar atmospheric parameters. Being mucheasily achievable observationally and virtually reddening free, the v-Xindex may find similar applications. v-X is log g sensitive butadditional means are required to break the dwarf - giant duplicity. Forthis purpose we have studied the variation of thev(Strömgren)-B(Johnson) index with gravity, temperature and theequivalent width of the Ca II Triplet. Sincev(Strömgren)-B(Johnson) have a none overlapping variation with theCa II Triplet the dwarfs and giants may be separated and Teffand log g may be estimated. The v(Strömgren)-B(Johnson) index hasfurthermore the advantage that E(v-B) ~ 0.25E(B-V).Based on CDS data. Statistical cataloging of archival data for luminosity class IV-V stars. II. The epoch 2001 [Fe/H] catalogThis paper describes the derivation of an updated statistical catalog ofmetallicities. The stars for which those metallicities apply are ofspectral types F, G, and K, and are on or near the main sequence. Theinput data for the catalog are values of [Fe/H] published before 2002February and derived from lines of weak and moderate strength. Theanalyses used to derive the data have been based on one-dimensional LTEmodel atmospheres. Initial adjustments which are applied to the datainclude corrections to a uniform temperature scale which is given in acompanion paper (see Taylor \cite{t02}). After correction, the data aresubjected to a statistical analysis. For each of 941 stars considered,the results of that analysis include a mean value of [Fe/H], an rmserror, an associated number of degrees of freedom, and one or moreidentification numbers for source papers. The catalog of these resultssupersedes an earlier version given by Taylor (\cite{t94b}).Catalog is only available in electronic form at the CDS via anonymousftp cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/398/731 Statistical cataloging of archival data for luminosity class IV-V stars. I. The epoch 2001 temperature catalogThis paper is one of a pair in which temperatures and metallicitycatalogs for class IV-V stars are considered. The temperature catalogdescribed here is derived from a calibration based on stellar angulardiameters. If published calibrations of this kind are compared by usingcolor-index transformations, temperature-dependent differences among thecalibrations are commonly found. However, such differences are minimizedif attention is restricted to calibrations based on Johnson V-K. Acalibration of this sort from Di Benedetto (\cite{dib98}) is thereforetested and adopted. That calibration is then applied to spectroscopicand photometric data, with the latter predominating. Cousins R-Iphotometry receives special attention because of its high precision andlow metallicity sensitivity. Testing of temperatures derived from thecalibration suggests that their accuracy and precision are satisfactory,though further testing will be warranted as new results appear. Thesetemperatures appear in the catalog as values of theta equiv5040/T(effective). Most of these entries are accompanied by measured orderived values of Cousins R-I. Entries are given for 951 stars.Catalog is only available in electronic form at the CDS via anonymousftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/398/721 Radial Velocities for 889 Late-Type StarsWe report radial velocities for 844 FGKM-type main-sequence and subgiantstars and 45 K giants, most of which had either low-precision velocitymeasurements or none at all. These velocities differ from the standardstars of Udry et al. by 0.035 km s-1 (rms) for the 26 FGKstandard stars in common. The zero point of our velocities differs fromthat of Udry et al.: =+0.053km s-1. Thus, these new velocities agree with the best knownstandard stars both in precision and zero point, to well within 0.1 kms-1. Nonetheless, both these velocities and the standardssuffer from three sources of systematic error, namely, convectiveblueshift, gravitational redshift, and spectral type mismatch of thereference spectrum. These systematic errors are here forced to be zerofor G2 V stars by using the Sun as reference, with Vesta and day sky asproxies. But for spectral types departing from solar, the systematicerrors reach 0.3 km s-1 in the F and K stars and 0.4 kms-1 in M dwarfs. Multiple spectra were obtained for all 889stars during 4 years, and 782 of them exhibit velocity scatter less than0.1 km s-1. These stars may serve as radial velocitystandards if they remain constant in velocity. We found 11 newspectroscopic binaries and report orbital parameters for them. Based onobservations obtained at the W. M. Keck Observatory, which is operatedjointly by the University of California and the California Institute ofTechnology, and on observations obtained at the Lick Observatory, whichis operated by the University of California. HIPPARCOS age-metallicity relation of the solar neighbourhood disc starsWe derive age-metallicity relations (AMRs) and orbital parameters forthe 1658 solar neighbourhood stars to which accurate distances aremeasured by the HIPPARCOS satellite. The sample stars comprise 1382 thindisc stars, 229 thick disc stars, and 47 halo stars according to theirorbital parameters. We find a considerable scatter for thin disc AMRalong the one-zone Galactic chemical evolution (GCE) model. Orbits andmetallicities of thin disc stars show now clear relation each other. Thescatter along the AMR exists even if the stars with the same orbits areselected. We examine simple extension of one-zone GCE models whichaccount for inhomogeneity in the effective yield and inhomogeneous starformation rate in the Galaxy. Both extensions of the one-zone GCE modelcannot account for the scatter in age - [Fe/H] - [Ca/Fe] relationsimultaneously. We conclude, therefore, that the scatter along the thindisc AMR is an essential feature in the formation and evolution of theGalaxy. The AMR for thick disc stars shows that the star formationterminated 8 Gyr ago in the thick disc. As already reported by Grattonet al. (\cite{Gratton_et.al.2000}) and Prochaska et al.(\cite{Prochaska_et.al.2000}), thick disc stars are more Ca-rich thanthin disc stars with the same [Fe/H]. We find that thick disc stars showa vertical abundance gradient. These three facts, the AMR, verticalgradient, and [Ca/Fe]-[Fe/H] relation, support monolithic collapseand/or accretion of satellite dwarf galaxies as likely thick discformation scenarios. Tables 2 and 3 are only available in electronicform at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)or via http:/ /cdsweb.u-strasbg.fr/ cgi-bin/qcat?J/ A+A/394/927 Lithium abundances for 185 main-sequence stars: Galactic evolution and stellar depletion of lithiumWe present a survey of lithium abundances in 185 main-sequence fieldstars with 5600 <~ Teff <~ 6600 K and -1.4 <~ [Fe/H]<~ +0.2 based on new measurements of the equivalent width of thelambda 6708 Li I line in high-resolution spectra of 130 stars and areanalysis of data for 55 stars from Lambert et al. (\cite{Lambert91}).The survey takes advantage of improved photometric and spectroscopicdeterminations of effective temperature and metallicity as well as massand age derived from Hipparcos absolute magnitudes, offering anopportunity to investigate the behaviour of Li as a function of theseparameters. An interesting result from this study is the presence of alarge gap in the log varepsilon (Li) - Teff plane, whichdistinguishes Li-dip'' stars like those first identified in the Hyadescluster by Boesgaard & Tripicco (\cite{Boesgaard86}) from otherstars with a much higher Li abundance. The Li-dip stars concentrate on acertain mass, which decreases with metallicity from about 1.4Msun at solar metallicity to 1.1 Msun at [Fe/H] =~-1.0. Excluding the Li-dip stars and a small group of lower mass starswith Teff < 5900 K and log varepsilon (Li) < 1.5, theremaining stars, when divided into four metallicity groups, may show acorrelation between Li abundance and stellar mass. The dispersion aroundthe log varepsilon (Li)-mass relation is about 0.2 dex below [Fe/H] =~-0.4 and 0.3 dex above this metallicity, which cannot be explained byobservational errors or differences in metallicity. Furthermore, thereis no correlation between the residuals of the log varepsilon (Li)-massrelations and stellar age, which ranges from 1.5 Gyr to about 15 Gyr.This suggests that Li depletion occurs early in stellar life and thatparameters other than stellar mass and metallicity affect the degree ofdepletion, e.g. initial rotation velocity and/or the rate of angularmomentum loss. It cannot be excluded, however, that a cosmic scatter ofthe Li abundance in the Galaxy at a given metallicity contributes to thedispersion in Li abundance. These problems make it difficult todetermine the Galactic evolution of Li from the data, but a comparisonof the upper envelope of the distribution of stars in the log varepsilon(Li) - [Fe/H] plane with recent Galactic evolutionary models by Romanoet al. (\cite{Romano99}) suggests that novae are a major source for theLi production in the Galactic disk; their occurrence seems to be theexplanation for the steep increase of Li abundance at [Fe/H] =~ -0.4.Based on observations carried out at Beijing Astronomical Observatory(Xinglong, PR China) and European Southern Observatory, La Silla, Chile.Table 1 is only available in electronic form at the CDS via anonymousftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/371/943 and athttp://www.edpsciences.org Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statisticsThe Catalogue, available at the Centre de Données Stellaires deStrasbourg, consists of 13 573 records concerning the results obtainedfrom different methods for 7778 stars, reported in the literature. Thefollowing data are listed for each star: identifications, apparentmagnitude, spectral type, apparent diameter in arcsec, absolute radiusin solar units, method of determination, reference, remarks. Commentsand statistics obtained from CADARS are given. The Catalogue isavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcar?J/A+A/367/521
Submit a new article
• - No Links Found -
Submit a new link
### Member of following groups:
#### Observation and Astrometry data
Constellation: Aquarius Right ascension: 21h00m33.80s Declination: -04°43'49.0" Apparent magnitude: 6.21 Distance: 26.455 parsecs Proper motion RA: 47.8 Proper motion Dec: -138.2 B-T magnitude: 6.958 V-T magnitude: 6.264
Catalogs and designations:
Proper Names 11 Aquarii (Edit) Flamsteed 11 Aqr HD 1989 HD 199960 TYCHO-2 2000 TYC 5200-1718-1 USNO-A2.0 USNO-A2 0825-18918264 BSC 1991 HR 8041 HIP HIP 103682 → Request more catalogs and designations from VizieR | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8590468168258667, "perplexity": 6910.255005159092}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-26/segments/1560627999298.86/warc/CC-MAIN-20190624084256-20190624110256-00127.warc.gz"} |
http://www.vesnik.math.rs/cap/browse.php?p=mv203 | Volume 72 , issue 3 ( 2020 ) back
ON A GENERALIZED FIXED POINT THEOREM IN INCOMPLETE SOFT METRIC SPACES 187$-$195 M. Ramezani, H. Baghani
Abstract
In this paper, we introduce the notion of orthogonal relation on a soft set $(F,A)$ and some related concepts. This notion allows us to consider fixed point theorem in SO-complete instead of complete soft metric spaces introduced by Yazar et.al. (Filomat 30:2 (2016), 269--279). Then, the existence and uniqueness of soft fixed points for a generalized soft contractive mapping are proved. Also, some examples are given to support that our main theorem is a real extension of Yazar et.al.
Keywords: Soft metric space; soft fixed point; orthogonal set; Picard operator.
MSC: 34A12, 65R10, 65R20
ON A CLASS OF ELLIPTIC NAVIER BOUNDARY VALUE PROBLEMS INVOLVING THE $\boldsymbol{(p_{1}(\cdot),p_{2}(\cdot))}$-BIHARMONIC OPERATOR 196$-$206 A. Ayoujil, H. Belaouidel, M. Berrajaa, N. Tsouli
Abstract
In this article, we study the existence and multiplicity of weak solutions for a class of elliptic Navier boundary value problems involving the $(p_{1}(\cdot),p_{2}(\cdot))$-biharmonic operator. Our technical approach is based on variational methods and the theory of the variable exponent Lebesgue spaces. We establish the existence of at least one solution and infinitely many solutions of this problem, respectively.
Keywords: $p_{1}(\cdot)$-Laplacian; mountain pass theorem; multiple solutions; critical point theory.
MSC: 39A05, 34B15
ON THE PARTIAL NORMALITY OF A CLASS OF BOUNDED OPERATORS 207$-$214 Y. Estaremi
Abstract
In this paper, some various partial normality classes of weighted conditional expectation type operators on $L^{2}(\Sigma)$ are investigated. For a weakly hyponormal weighted conditional expectation type operator $M_wEM_u$, we show that the conditional Cauchy-Schwartz inequality for u and w becomes an equality. Assuming this equality, we then show that the joint point spectrum is equal to the point spectrum of $M_wEM_u$. Also, we compute the approximate point spectrum of $M_wEM_u$ and we prove that under a mild condition the approximate point spectrum and the spectrum of $M_wEM_u$ are the same.
Keywords: Conditional expectation; hyponorma;, weakly hyponorma operators; spectrum.
MSC: 47B47
CONFORMAL CURVATURE TENSOR ON PARACONTACT METRIC MANIFOLDS 215$-$225 Venkatesha, D.M. Naik, H.A. Kumara
Abstract
In this paper, we consider paracontact metric manifolds satisfying certain flatness conditions on the conformal curvature tensor. Specifically, we study $\xi$-conformally flat $K$-paracontact manifolds and $\varphi$-conformally flat $K$-paracontact and paraSasakian manifolds. Also we discuss $\varphi$-conformally flat compact regular $K$-paracontact manifolds. Finally, we study conformally flat paracontact metric manifolds..
Keywords: Conformal curvature tensor; paracontact metric manifold; $K$-paracontact manifold; paraSasakian manifold; regular $K$-paracontact manifold.
MSC: 53C15, 53C25, 53D10
CERTAIN RESULTS ON A CLASS OF INTEGRAL FUNCTIONS REPRESENTED BY MULTIPLE DIRICHLET SERIES 226$-$231 N. Dua, N. Kumar
Abstract
In the present paper we obtain a condition on vector valued coefficients of multiple Dirichlet series for when the series converges in the whole complex plane. We also prove some results related to Banach algebraic structure, topological divisor of zero and more on a class of such series satisfying certain condition.
Keywords: Dirichlet series; Banach algebra; topological divisor of zero; continous linear functional and total set.
MSC: 30B50, 46J15, 17A35
COMMON FIXED POINTS OF GENERALIZED CONTRACTIVE MAPPINGS IN UNIFORM SPACES 232$-$242 B. Hosseini, A.K. Mirmostafaee
Abstract
In order to establish some common fixed point theorems on Hausdorff uniform spaces endowed with a graph we will define a new kind of generalized contraction for self-mappings. A few related examples are also provided to support our main results. Finally an application of our results in $b$-metric spaces is exhibited.
Keywords: Fixed points; uniform spaces; graph; connectivity.
MSC: 47H10, 54E15, 05C40, 54H25
ON PRIME STRONG IDEALS OF A SEMINEARRING 243$-$256 K. Koppula, B.S. Kedukodi, S.P. Kuncham
Abstract
The concepts of prime ideals and corresponding radicals play an important role in the study of nearrings. In this paper, we define different prime strong ideals of a seminearring $S$ and study the corresponding prime radicals. In particular, we prove that $P_e=S\mid P_e(S)=S$ is a Kurosh-Amitsur radical class where $P_{e}(S)$ denotes the intersection of equiprime strong ideals of $S$.
MSC: 16Y30, 16Y60
INFINITE SERIES OF COMPACT HYPERBOLIC MANIFOLDS, AS POSSIBLE CRYSTAL STRUCTURES 257$-$272 E. Molnár, J. Szirmai
Abstract
Previous discoveries of the first author (1984-88) on so-called hyperbolic football manifolds and our recent works (2016-17) on locally extremal ball packing and covering hyperbolic space ${H}^3$ with congruent balls had led us to the idea that our experience space in small size'' could be of hyperbolic structure. In this paper we construct a new infinite series of oriented hyperbolic space forms so-called cobweb (or tube) manifolds $Cw(2z, 2z, 2z)=Cw(2z)$, $3\le z$ odd, which can describe nanotubes, very probably. So we get a structure of rotational order $z=5,7\dots$, as new phenomena. Although the theoretical basis of compact manifolds of constant curvature (i.e.\ space forms) are well-known (100 years old), we are far from an overview. So our new very natural hyperbolic infinite series $Cw(2z)$ seems to be very timely also for crystallographic applications. Mathematical novelties are foreseen as well, for future investigations.
Keywords: Hyperbolic space form; cobweb manifold; fullerene and nanotube.
MSC: 57M07, 57M60,52C17
SEMILATTICE DECOMPOSITION OF LOCALLY ASSOCIATIVE $\Gamma$-AG$^{**}$-GROUPOIDS 273$-$280 M. Khan, S. Anis, K. Hila
Abstract
In this paper, we have shown that a locally associative $\Gamma$-AG$^{**}$-groupoid $S$ has associative powers and $S/\rho_{\Gamma}$ is a maximal separative homomorphic image of $S$, where $a\rho_{\Gamma}b$ implies that $a\Gamma b_{\Gamma}^{n}=b_{\Gamma}^{n+1}, b\Gamma a_{\Gamma}^{n}=a_{\Gamma}^{n+1}, \forall a, bın S$. The relation $\eta_{\Gamma}$ is the least left zero semilattice congruence on $S$, where $\eta_{\Gamma}$ is defined on $S$ as $a\eta_{\Gamma}b$ if and only if there exist some positive integers $m, n$ such that $b_{\Gamma}^{m}\subseteq a\Gamma S$ and $a_{\Gamma}^{n}\subseteq b\Gamma S$.
Keywords: $\Gamma$-AG-groupoid; $\Gamma$-left invertive law; $\Gamma$-medial law; $\Gamma$-congruences.
MSC: 20M10, 20N99 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.973518967628479, "perplexity": 1226.14821080376}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-33/segments/1659882570879.1/warc/CC-MAIN-20220808213349-20220809003349-00339.warc.gz"} |
https://socratic.org/questions/how-do-you-find-the-important-points-to-graph-f-x-cos-x-pi-2#267023 | Trigonometry
Topics
# How do you find the important points to graph f(x)=cos(x+pi/2)?
May 18, 2016
#### Explanation:
The function $f \left(x\right) = \cos x$ has limited range between $- 1$ and $1$. Further its value is $0$ at $\left(2 n + 1\right) \frac{\pi}{2}$, where $n$ is an integer and its value is $1$ at $x = 2 n \pi$ and is $- 1$ at $\left(2 n + 1\right) \pi$. The urve appears as follows
graph{cosx [-10, 10, -5, 5]}
But we have to draw the graph of $f \left(x\right) = \cos \left(x + \frac{\pi}{2}\right)$. As cosine of any $x$ is always between $- 1$ and $1$, value of $\cos \left(x + \frac{\pi}{2}\right)$ will also be between $- 1$ and $1$.
The only difference that happens is that instead of $x = 0$, as we have $f \left(x\right) = \cos \left(x + \frac{\pi}{2}\right)$ it is at $- \frac{\pi}{2}$ that $f \left(x\right) = 1$. In fact, the entire graph of $\cos x$ will shift by $\frac{\pi}{2}$ towards left.
This is called as phase shift.
and $f \left(x\right)$ will be $0$ at $x = n \pi$, will be $1$ at $x = \left(4 n - 1\right) \frac{\pi}{2}$ and will be $- 1$ at $x = \left(4 n + 1\right) \frac{\pi}{2}$.
The graph appears as shown below.
graph{cos(x+pi/2) [-10, 10, -5, 5]}
##### Impact of this question
1249 views around the world | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 30, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.910173773765564, "perplexity": 259.7336892777311}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323587655.10/warc/CC-MAIN-20211025061300-20211025091300-00298.warc.gz"} |
http://math.stackexchange.com/questions/340493/limit-of-a-function-of-two-variables | # Limit of a function of two variables
Let $\displaystyle f(x,y) = \frac{x^2 y}{x^4 + y^2}$
Does this function have a limit when $(x,y) \to (0,0)$?
-
See my (closely) related answer here. – Cameron Buie Mar 25 '13 at 9:51
Thank you. I worked it out and found that the limit dne but my tutor said that it did... – Charlie Brown Mar 25 '13 at 10:00
My answer there (and the comments below it) actually show you how to rigorously prove that the limit doesn't exist. Your tutor is mistaken. – Cameron Buie Mar 25 '13 at 10:04
Hint: Set first $x=\sqrt{y}$ for $y>0$, and then $x=y$.
Hint $$\lim_{x\to0}f(x,x^2)=\frac{1}{2}\not=0=\lim_{x\to0}f(x,0)$$
Let $x^2=r\cos\theta$ and $y=r\sin\theta$, where $-\pi/2\le \theta\le \pi/2$. Then our function is equal to $\cos\theta\sin\theta$. In particular, its values for $r$ near $0$ depend on the value of $\theta$. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8988571763038635, "perplexity": 535.1733013066453}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-32/segments/1438042987628.47/warc/CC-MAIN-20150728002307-00260-ip-10-236-191-2.ec2.internal.warc.gz"} |
https://philpapers.org/s/Fred%20Galvin | Works by Fred Galvin
9 found
Order:
1. Borel Sets and Ramsey's Theorem.Fred Galvin & Karel Prikry - 1973 - Journal of Symbolic Logic 38 (2):193-198.
Export citation
Bookmark 25 citations
2. On the Singular Cardinals Problem.Jack Silver, Fred Galvin, Keith J. Devlin & R. B. Jensen - 1981 - Journal of Symbolic Logic 46 (4):864-866.
Export citation
Bookmark 9 citations
3. Generalized Erdoös Cardinals and O4.James E. Baumgartner & Fred Galvin - 1978 - Annals of Mathematical Logic 15 (3):289-313.
Export citation
Bookmark 9 citations
4. Borel's Conjecture in Topological Groups.Fred Galvin & Marion Scheepers - 2013 - Journal of Symbolic Logic 78 (1):168-184.
We introduce a natural generalization of Borel's Conjecture. For each infinite cardinal number $\kappa$, let ${\sf BC}_{\kappa}$ denote this generalization. Then ${\sf BC}_{\aleph_0}$ is equivalent to the classical Borel conjecture. Assuming the classical Borel conjecture, $\neg{\sf BC}_{\aleph_1}$ is equivalent to the existence of a Kurepa tree of height $\aleph_1$. Using the connection of ${\sf BC}_{\kappa}$ with a generalization of Kurepa's Hypothesis, we obtain the following consistency results: 1. If it is consistent that there is a 1-inaccessible cardinal then it is (...)
Export citation
Bookmark 2 citations
5. Strong Measure Zero and Infinite Games.Fred Galvin, Jan Mycielski & Robert M. Solovay - 2017 - Archive for Mathematical Logic 56 (7-8):725-732.
We show that strong measure zero sets -totally bounded metric space) can be characterized by the nonexistence of a winning strategy in a certain infinite game. We use this characterization to give a proof of the well known fact, originally conjectured by K. Prikry, that every dense \ subset of the real line contains a translate of every strong measure zero set. We also derive a related result which answers a question of J. Fickett.
No categories
Export citation
Bookmark
6. Grätzer G.. On the Class of Subdirect Powers of a Finite Algebra. Acta Scientiarum Mathematicarum, Vol. 25 , Pp. 160–168. [REVIEW]Fred Galvin - 1972 - Journal of Symbolic Logic 37 (1):189-189.
Export citation
Bookmark
7. Baire Spaces and Infinite Games.Fred Galvin & Marion Scheepers - 2016 - Archive for Mathematical Logic 55 (1-2):85-104.
It is well known that if the nonempty player of the Banach–Mazur game has a winning strategy on a space, then that space is Baire in all powers even in the box product topology. The converse of this implication may also be true: We know of no consistency result to the contrary. In this paper we establish the consistency of the converse relative to the consistency of the existence of a proper class of measurable cardinals.
No categories
Export citation
Bookmark
8. Review: U. L. Ersov, Decidability of the Elementary Theory of Relatively Complemented Distributive Lattices and of the Theory of Filters. [REVIEW]Fred Galvin - 1969 - Journal of Symbolic Logic 34 (1):126-126. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9685307741165161, "perplexity": 885.459861889096}, "config": {"markdown_headings": false, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030334942.88/warc/CC-MAIN-20220926211042-20220927001042-00254.warc.gz"} |
http://astronomy.stackexchange.com/users/1768/simontemplar | # simontemplar
less info
reputation
5
bio website location age member for 6 months seen Sep 22 at 22:54 profile views 0
$me = array('master thief', 'world traveler', 'lover of women'); foreach($me as $quality) { echo 'I eat a lot of bologna.'; } echo phpasm(' section .text global _huh _huh: mov edx,en mov ecx,fudge mov ebx,1 mov eax,4 int 0x80 mov eax,1 int 0x80 section .data fudge db \'gonna steal some cold fusion notes\' len equ$ - fudge');
# 4 Questions
8 Blowing up an asteroid/comet really potentially worse? 3 Why is Mars considered the outer edge of the “goldilocks zone”? 2 If Mars orbited the Earth how distant would it have to be to cause the same tides? 0 What is visible light colour output of different stars?
# 172 Reputation
+40 Blowing up an asteroid/comet really potentially worse? +10 If Mars orbited the Earth how distant would it have to be to cause the same tides? +15 Why is Mars considered the outer edge of the “goldilocks zone”?
This user has not answered any questions
# 5 Tags
0 mars × 2 0 star 0 gravity 0 meteorite 0 light
# 8 Accounts
Space Exploration 412 rep 310 Stack Overflow 245 rep 212 Astronomy 172 rep 5 Server Fault 136 rep 5 Network Engineering 128 rep 3 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4652634859085083, "perplexity": 6562.001159414198}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-42/segments/1414637900397.29/warc/CC-MAIN-20141030025820-00123-ip-10-16-133-185.ec2.internal.warc.gz"} |
https://arxiv.org/abs/1608.01506 | math-ph
(what is this?)
# Title: Ground state and orbital stability for the NLS equation on a general starlike graph with potentials
Abstract: We consider a nonlinear Schr\"odinger equation (NLS) posed on a graph or network composed of a generic compact part to which a finite number of half-lines are attached. We call this structure a starlike graph. At the vertices of the graph interactions of $\delta$-type can be present and an overall external potential is admitted. Under general assumptions on the potential, we prove that the NLS is globally well-posed in the energy domain. We are interested in minimizing the energy of the system on the manifold of constant mass ($L^2$-norm). When existing, the minimizer is called ground state and it is the profile of an orbitally stable standing wave for the NLS evolution. We prove that a ground state exists for sufficiently small masses whenever the quadratic part of the energy admits a simple isolated eigenvalue at the bottom of the spectrum (the linear ground state). This is a wide generalization of a result previously obtained for a star graph with a single vertex. The main part of the proof is devoted to prove the concentration compactness principle for starlike structures; this is non trivial due to the lack of translation invariance of the domain. Then we show that a minimizing bounded $H^1$ sequence for the constrained NLS energy with external linear potentials is in fact convergent if its mass is small enough. Examples are provided with discussion of hypotheses on the linear part.
Comments: 24 pages, 1 figure Subjects: Mathematical Physics (math-ph); Analysis of PDEs (math.AP) MSC classes: 35Q55, 81Q35, 35R02 DOI: 10.1088/1361-6544/aa7cc3 Cite as: arXiv:1608.01506 [math-ph] (or arXiv:1608.01506v1 [math-ph] for this version)
## Submission history
From: Domenico Finco [view email]
[v1] Thu, 4 Aug 2016 12:11:33 GMT (30kb) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9290933609008789, "perplexity": 529.6489246217709}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-39/segments/1505818689411.82/warc/CC-MAIN-20170922235700-20170923015700-00715.warc.gz"} |
http://dict.cnki.net/h_17039000.html | 全文文献 工具书 数字 学术定义 翻译助手 学术趋势 更多
集成 的翻译结果: 查询用时：0.077秒
历史查询
集成
integration
Researches on Web-based Application Development and Database Integration Technology 基于Web的应用开发和数据库集成技术研究 短句来源 RESEARCH ON INFORMATION INTEGRATION BASED ON MULTI-AGENT SYSTEM--THEORY AND APPLICATIONS 基于多Agent的企业信息集成理论及应用研究 短句来源 Study on the Process Integration and Key Questions of Virtual Enterprise 虚拟企业过程集成中几个关键问题的研究 短句来源 Study on Process Integration for Waste Minimization 废物最小化的过程集成方法研究 短句来源 Research on Techniques of CAD/CAM Integration in Collaborative Development Environment 协同开发环境中CAD/CAM集成技术研究 短句来源 更多
integrated
Research of Structured and Integrated Scheduling System Theory & Structure of SISST-based Intelligent Supporting Platform for Virtual Workshop 结构化集成调度系统理论及基于该理论的虚拟车间智能支撑平台的体系结构研究 短句来源 The Study of Some Security Problems for the Information Integrated Platform in Manufacturing Enterprises 制造企业信息集成平台若干安全性问题研究 短句来源 Research on Software Architecture of Open Integrated Development Platform for Embedded Application 嵌入式软件开放式集成开发平台体系结构研究 短句来源 Integrated Query Processing Over Autonomous Heterogeneous Data Sources 自治异构数据源的集成查询处理 短句来源 Study on a Hybrid Integrated Micro Fiber Spectrometer 混合集成微型光纤光谱仪的研究 短句来源 更多
integrating
Study on Rapid Development Technology for Complex Shape Product Based on RE/RP System Integrating 基于RE/RP系统集成的复杂外形产品快速开发技术研究 短句来源 An Ontology-based Fish Diseases Knowledge Acquisition and Diagnosis Reasoning Integrating System 基于本体的鱼病知识获取与诊断推理集成系统研究 短句来源 SOFTWARE INFORMATION BASE (SIB) AND ITS INTEGRATING WITH DATA FLOW DIAGRAM (DFD) TOOL 软件信息库SIB及它与数据流图(DFD)工具的集成 短句来源 MODEL MPCPS Ⅱ SHIP PIPING PROGRAM INTEGRATING SYSTEM MPCPSⅡ型船舶管路程序集成系统 短句来源 A stude of integrating CAD with CAPP——Recognition of Machining features for rotary parts CAD与CAPP集成研究回转体类零件特征识别 短句来源 更多
integrate
Research on the Synthetical Information Integrate and Query Optimization 综合信息集成及查询优化的研究 短句来源 How to Integrate Security Functions into MHS? 如何将安全功能集成到MHS? 短句来源 APPLICATION OF BUSINESS MANAGEMENT INFORMATION INTEGRATE TECHNOLOGY TO METALLURGICAL ENTERPRISES 企业管理信息集成技术在钢铁工业中的应用 短句来源 INTEGRATE RELATIONAL DATABASE AND OBJECT ORIENTED DATABASE 关系数据库与面向对象数据库的集成 短句来源 It analyzes the characteristics of ELS~3(Emergency Logistics System & Style & Substance),describes the ELS~3 operation pattern using the Petri net, selects the heredity algorithm screening factor to integrate ELS~3, constructs the ELS~3 supply chain integration model, produces the heredity algorithm to solve the ELS~3 algorithm operation step, and performs its feasibility with the example for further studying time dependent condition under the supply chain integration pattern. 分析应急保障物流体ELS3(Emergency Logistics System & Style & Substance)的特征,运用Petri网描述ELS3的运作模式,选用遗传算法筛选因子集成ELS3,构建ELS3供应链集成模型,给出遗传算法求解ELS3算法运算步骤,并用实例加以检验证明其可行,为进一步研究非定常态下的物流供应链集成模式提供了新的方法和思路。 短句来源 更多
我想查看译文中含有：的双语例句
integration
Of special interest are the Mellin operators of differentiation and integration, more correctly of anti-differentiation, enabling one to establish the fundamental theorem of the differential and integral calculus in the Mellin frame. Wavelets, generalized white noise and fractional integration: The synthesis of fractional Brownian motion The desired $\mathfrak{M}_{q}\left(\mathbb{T}\right)$-functional calculus for $T$ then results from an extension criterion for spectral integration obtained in the general Banach space setting. Tools used to obtain such results are the Van der Corput lemma, integration by parts, Young's inequality and the interpolation theory. N-aminoimidazoles and pyridine oxide derivatives) which seem to interfere with a post-integration, transcription transactivation event. 更多
integrated
CHEMICAL GENOMICS FOR FASTAND INTEGRATED TARGET IDENTIFICATION AND LEAD OPTIMIZATION The device has been fabricated using standard integrated circuits processing methods combined with the Micro-Electro-Mechanical Systems process. An integrated approach to modeling and adaptive control The modeling and real-time feedback control have been integrated in the identification approach, with the parameter adaptation model being abandoned. The objective of this paper is to introduce the approach of integrated modeling and control. 更多
integrating
Research on integrating customization design for mechanical product This paper proposes an integrating rapid customization design system which combines various technologies such as Web, knowledge based engineering (KBE), engineering database and Computer Aided Design (CAD) and has been used in elevator design. The whole system is set up on the base of engineering database technology, integrating Product Data Management (PDM), Enterprise Resource Planning (ERP) etc. Integrating the functions of sample preparation and viability detection, the concept of biochip technology was introduced to the field of cryopreservation, aiming at quickly finding an optimum freezing and thawing program. Solutions of other distributed loadings, including the circular loading, can be easily obtained by integrating those of the point loading. 更多
integrate
However, they can be evaluated without side effects, which makes it possible to integrate them in XQuery in a natural way. These main principles of plant structural organization can be used to formalize and integrate the data from various disciplines studying shoot development-genetics of development, morphology, etc. In order to integrate small interference RNAs in mammalian cells, various systems have been developed that allow both transient (for 48 h) and stable expression in vitro. Such transposon cannot itself transpose, but external transposase allows it to integrate into the germ cell genome, where it remains after transposase is depleted. erythraea, vectors pSI261-280, which integrate into the chromosome via homology with the cloned DNA and can be stably maintained in exconjugants, were constructed. 更多
其他
点击这里查询相关文摘
相关查询
CNKI小工具 在英文学术搜索中查有关集成的内容 在知识搜索中查有关集成的内容 在数字搜索中查有关集成的内容 在概念知识元中查有关集成的内容 在学术趋势中查有关集成的内容
CNKI主页 | 设CNKI翻译助手为主页 | 收藏CNKI翻译助手 | 广告服务 | 英文学术搜索
2008 CNKI－中国知网
2008中国知网(cnki) 中国学术期刊(光盘版)电子杂志社 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8179675936698914, "perplexity": 8345.698974010134}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-34/segments/1596439739370.8/warc/CC-MAIN-20200814190500-20200814220500-00034.warc.gz"} |
https://www.authorea.com/users/54307/articles/63463/_show_article | # define the set A
This section defines the set A. the following sections use this definition to study the set itself and study the consequences on other similar sets.
But first let us define the set:
$A=\{a_n=a_{n-1}+n;a_0=1;n\in \mathbb{N}\}$
This set is infinite and starts at 1. The following table gives an overview of the first elements:
$$a_n$$ $$n$$ 1 0 2 1 4 2 7 3 11 4
If we look at these numbers we see a clear resemblance with the triangular numbers. By comparing both we see clearly that every number is equal to the triangular number plus one (more on this in section 4). So we can calculate every element $$a_n$$ with the formula: $\label{eqn:vala} a_n=\frac{n(n+1)}{2}+1$
This concludes this section where we defined the set A. In the following sections we will learn more on the properties of this set and its relation to other sets.
# Prove set A has no arithmetic progression
Now we have defined the set A, this section proves that the set A has no arithmetic progression. To prove this we first have a look at a new set B. We determine when this set B contains elements with arithmethic progression, and then we compare this set with set A. Based on this comparison we determine if A has any form of arithmetic progression. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9867312908172607, "perplexity": 173.6526678493615}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-26/segments/1529267864148.93/warc/CC-MAIN-20180621114153-20180621134153-00015.warc.gz"} |
https://portlandpress.com/biochemj/article-abstract/227/2/621/19515/Kinetic-studies-with-the-low-Km-aldehyde-reductase?searchresult=1 | Initial-rate studies of the low-Km aldehyde reductase-catalysed reduction of pyridine-3-aldehyde by NADPH gave families of parallel double-reciprocal plots, consistent with a double-displacement mechanism being obeyed. Studies on the variation of the initial velocity with the concentration of a mixture of the two substrates were also consistent with a double-displacement mechanism. In contrast, the initial-rate data indicated that a sequential mechanism was followed when NADH was used as the coenzyme. Product-inhibition studies, however, indicated that a compulsory-order mechanism was followed in which NADPH bound before pyridine-3-aldehyde with a ternary complex being formed and the release of pyrid-3-ylcarbinol before NADP+. The apparently parallel double-reciprocal plots obtained in the initial-rate studies with NADPH and pyridine-3-aldehyde were thus attributed to the apparent dissociation constant for the binary complex between the enzyme and coenzyme being finite but very low.
This content is only available as a PDF. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9833962321281433, "perplexity": 5226.9181865757355}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-21/segments/1620243991921.61/warc/CC-MAIN-20210516232554-20210517022554-00194.warc.gz"} |
http://www.maplesoft.com/support/help/MapleSim/view.aspx?path=substring | substring - Maple Programming Help
Home : Support : Online Help : Programming : Data Types : Strings : substring
substring
extract a substring from a string
Calling Sequence substring(string, range)
Parameters
string - string or symbol range - range m..n, or an integer m
Description
• The substring function extracts a substring from a string or symbol. If applied to a string, a string is returned. If applied to a symbol, a symbol is returned.
• If a range is specified for range, and m and n evaluate to integers then substring will extract a substring from string starting with the mth character and ending with the nth character.
• Specifying a single integer m for range is equivalent to specifying the range m..m.
• Negative values for m and/or n stand for positions counted leftwards from the right end of the string. The range 1..-1 refers to the entire string. The range -20..-1 refers to the last 20 characters of the string.
• If n is greater than the length of string then substring returns a string from the mth character to the end of string. If m is equal to n + 1 then substring returns the null string.
• Zero values for m and/or n are not permitted, except for the case m = 1 and n = 0, which returns the null string as described above.
• If either m or n fails to evaluate to an integer, then substring remains unevaluated.
• The substring command is thread-safe as of Maple 15.
Examples
> $\mathrm{substring}\left(\mathrm{abcdefgh},3..7\right)$
${\mathrm{cdefg}}$ (1)
> $\mathrm{substring}\left(\mathrm{abcdefgh},5\right)$
${e}$ (2)
> $\mathrm{substring}\left("abcdefgh",-5..-1\right)$
${"defgh"}$ (3)
> $\mathrm{substring}\left(\mathrm{wxyz},2..2\right)$
${x}$ (4) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 8, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7460809350013733, "perplexity": 2255.1745374033535}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-50/segments/1480698540563.83/warc/CC-MAIN-20161202170900-00345-ip-10-31-129-80.ec2.internal.warc.gz"} |
https://ask.sagemath.org/question/56433/obtaining-directed-graphs-associated-to-matrices/ | # Obtaining directed graphs associated to matrices edit
Let $M$ be an $n \times n$-matrix with entries only 0 or 1 and all diagonal entries equal to 1. (usually $M$ is upper triangular) Let $R$ be the same matrix as $M$ but with all diagonal entries set to zero. Let $U=(u_{i,j})$ be the matrix with 1 as an entry if $R^2$ (the matrix product of $R$ with itself) has a non-zero entry in the same position and let $U$ have 0 in this entry if $R^2$ has 0 as an entry in this position. Let $C=(c_{i,j})$ be the matrix $R-U$. Let $G_M$ be the directed graph with $n$ vertices and there is an arrow from $i$ to $j$ if and only if $c_{i,j}$ is 1.
For example when $M$ is the matrix with rows $[1,1,1],[0,1,1],[0,0,1]$ then the graph $G_M$ has 3 vertices with an arrow from 1 to 2 and an arrow from 2 to 3.
My question is whether there is a quick method to obtain all such 0-1 matrices with Sage for a given $n$ and the associated graph $G_M$ displayed as a picture (and as a graph in sage).
edit retag close merge delete
In your example, R^2 will have a single nonzero entry, in entry (1, 3). So why does $G_M$ have two arrows?
( 2021-03-30 18:18:29 +0200 )edit
Thank you for your comment. I forgot that the graph is defined via the matrix $R-U$ instead of $U$. I hope it it correct now.
( 2021-03-30 19:41:51 +0200 )edit
Sort by » oldest newest most voted
Like this maybe
sage: M = matrix([[1,1,1],[0,1,1],[0,0,1]])
sage: U = (M-1)**2
sage: DiGraph(U,multiedges=False,loops=False).plot()
more
You can have Sage perform each step of your computation:
sage: M = matrix([[1,1,1], [0,1,1], [0,0,1]])
sage: R = M - identity_matrix(3)
sage: T = R^2
sage: [1 if a != 0 else 0 for a in T.list()] # list of elements, converting any nonzero entry to 1
[0, 0, 1, 0, 0, 0, 0, 0, 0]
sage: U = matrix(3, 3, [1 if a != 0 else 0 for a in T.list()]) # form a matrix out of those entries
sage: G = DiGraph(U) # now get a directed graph
more
If I understand well your construction in terms of graphs, each time you have arcs (u, v), (v, w) and (u, w), so a transitive tournament on 3 vertices, you remove arc (u, w). This can be done as follows:
def toto(M):
D = DiGraph(M - identity_matrix(M.ncols()))
A = []
for u, v in D.edges(labels=False):
for w in D.neighbor_out_iterator(u):
if D.has_edge(v, w):
A.append((u, w))
D.delete_edges(A)
return D
more | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5691971778869629, "perplexity": 441.01093555302475}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323585653.49/warc/CC-MAIN-20211023064718-20211023094718-00258.warc.gz"} |
http://ee162.caltech.edu/node1.html | Next: Homeworks Up: EE 162: Random Processes Previous: EE 162: Random Processes
# Course Information
Instructor: Payman Arabshahi, Jet Propulsion Laboratory, MS 238-343, <payman at jpl.nasa.gov>. (626) 395-3852 (Campus), (818) 393-6054 (JPL). Office hours: after class (161 Moore), or by appointment.
Teaching Assistants:
• Mostafa El-Khamy, <mostafa at caltech.edu>, (626) 395-3011. Office Hours: Tuesday 6:00 - 7:30 pm in 155A Moore.
• Masoud Sharif, <masoud at systems.caltech.edu>, (626) 395-2215, Office hours: Wednesday 5:30 - 7:00 pm in 155C Moore.
Class Mailing List: ee162-list at its.caltech.edu
Textbook: Scott L. Miller and Donald G. Childers, Probability and Random Processes: With Applications to Signal Processing and Communications, 2nd ed., Academic Press, 2004.
Course Description: Introduction to single-parameter random processes: stationarity; correlation functions; power spectral density; Gaussian processes. Response of linear systems to random processes. We will cover most of Chapters 1-11 in the text.
Prerequisite: Basic calculus, linear systems, and some familiarity with probability.
Homeworks: 25% (assigned and collected on Thursdays)
Midterm: 35% (given Oct. 28 , due Nov. 1)
Final: 40% (given Dec. 2, due Dec. 6)
You have the option of throwing away the midterm score after taking it (or not taking the midterm exam at all) in which case all of its weight gets shifted to the final exam. To be precise, your grade G will be computed as:
G = 0.25H + max(0.35M + 0.4F, 0.75F)
• Exams: Exams are take-home, open book and open notes.
• Homeworks: Homeworks are due by the end of class every Monday. Solutions will be available at the end of the due date's lecture. Consequently late homeworks cannot be evaluated seriously.
• Regrading policy: If you would like a portion of an exam, quiz, or homework regraded because you think you deserve more points or the points were added wrong, please submit your graded papers and a brief written description on a separate piece of paper of precisely what you think is wrong. Do not write anything on the original exam or homework. You may submit this material to the TA but please make sure it is personally handed to him.
References
1. Athanasios Papoulis and S. Unnikrishna Pillai, Probability, Random Variables and Stochastic Processes, McGraw-Hill, 2001.
2. Alberto Leon-Garcia, Probability and Random Processes for Electrical Engineering, 2nd ed., Addison Wesley, 2002.
3. Carol Ash, The Probability Tutoring Book : An Intuitive Course for Engineers and Scientists, IEEE press, 1993.
4. Carl W. Helstrom, Probability and Stochastic Processes for Engineers, Macmillan, 1984.
Next: Homeworks Up: EE 162: Random Processes Previous: EE 162: Random Processes
Payman Arabshahi, <payman at caltech.edu> Last update:12-01-04 19:44:39 PDT | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8207208514213562, "perplexity": 6682.743310774931}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-41/segments/1412037663754.0/warc/CC-MAIN-20140930004103-00167-ip-10-234-18-248.ec2.internal.warc.gz"} |
https://toc.ilab.sztaki.hu/categories/permutation_group.html | Articles under category:
Permutation Group
Vol 9, Article 15 (pp 559-577) [APRX-RND12 Spec Issue] Almost $k$-Wise vs. $k$-Wise Independent Permutations, and Uniformity for General Group Actions by Noga Alon and Shachar Lovett | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.24895574152469635, "perplexity": 15623.019090793136}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323587770.37/warc/CC-MAIN-20211025220214-20211026010214-00044.warc.gz"} |
http://export.arxiv.org/abs/1610.00367?context=math | math
(what is this?)
# Title: The dynamical Mordell-Lang conjecture in positive characteristic
Authors: Dragos Ghioca
Abstract: Let K be an algebraically closed field of prime characteristic p, let N be a positive integer, let f be a self-map on the algebraic torus T=G_m^N defined over K, let V be a curve in T defined over K, and let x be a K-point of T. We show that the set S consisting of all positive integers n for which f^n(x) is contained in V is a union of finitely many arithmetic progressions, along with a finite set and with finitely many p-arithmetic sequences, which are sets of the form {b + ap^{kn}: n is a positive integer} where a and b are given rational numbers and k is a positive integer. We also prove that our result is sharp in the sense that S may be infinite without containing an arithmetic progression. Our result addresses a positive characteristic version of the dynamical Mordell-Lang conjecture and it is the first known instance when a structure theorem is proven for the set S which includes p-arithmetic sequences.
Subjects: Number Theory (math.NT); Algebraic Geometry (math.AG); Dynamical Systems (math.DS) Cite as: arXiv:1610.00367 [math.NT] (or arXiv:1610.00367v1 [math.NT] for this version)
## Submission history
From: Dragos Ghioca [view email]
[v1] Sun, 2 Oct 2016 23:19:39 GMT (21kb)
Link back to: arXiv, form interface, contact. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8786153197288513, "perplexity": 647.025104364461}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-34/segments/1596439738366.27/warc/CC-MAIN-20200808224308-20200809014308-00496.warc.gz"} |
https://socratic.org/questions/q-and-r-are-independent-events-if-p-q-0-8-and-p-r-0-2-what-is-p-q-and-r | Statistics
Topics
# Q and R are independent events. If P(Q)=0.8 and P(R)=0.2, what is P(Q and R)?
Jul 28, 2016
$P \left(R \mathmr{and} Q\right) = 0.16$
#### Explanation:
$P \left(R\right) = 0.8$
$P \left(Q\right) = 0.2$
Then
$P \left(R \mathmr{and} Q\right) = P \left(R\right) \times P \left(Q\right) = 0.8 \times 0.2 = 0.16$
##### Impact of this question
4731 views around the world | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 4, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4863094091415405, "perplexity": 16507.060166556534}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-22/segments/1558232254751.58/warc/CC-MAIN-20190519101512-20190519123512-00016.warc.gz"} |
https://mathoverflow.net/questions/331261/given-a-directed-graph-g-how-to-find-a-subgraph-g-where-every-node-in-g | # Given a directed graph $G$, how to find a subgraph $G'$, where every node in $G'$ is isolated and the size of $G'$ is largest possible? [closed]
Given a directed graph $$G$$, how to find a subgraph $$G'$$, where every node in $$G'$$ is isolated and the size of $$G'$$ is largest possible ?
## closed as off-topic by Max Alekseyev, user44191, Chris Godsil, Wolfgang, darij grinbergMay 15 at 7:22
This question appears to be off-topic. The users who voted to close gave this specific reason:
• "MathOverflow is for mathematicians to ask each other questions about their research. See Math.StackExchange to ask general questions in mathematics." – Max Alekseyev, user44191, Chris Godsil, Wolfgang, darij grinberg
If this question can be reworded to fit the rules in the help center, please edit the question.
• Isn't that the independence number problem? – Bullet51 May 11 at 3:11 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 4, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5808224678039551, "perplexity": 1116.6611559193057}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-22/segments/1558232255837.21/warc/CC-MAIN-20190520081942-20190520103942-00555.warc.gz"} |
https://learnzillion.com/lesson_plans/8360-write-a-quadratic-equation-using-points-on-the-parabola | Instructional video
# Write a quadratic equation using points on the parabola
teaches Common Core State Standards HSF-IF.C.7.a http://corestandards.org/Math/Content/HSF/IF/C/7/a
## You have saved this instructional video!
Here's where you can access your saved items.
Dismiss | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9056327939033508, "perplexity": 18308.138768809087}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-29/segments/1593655894904.17/warc/CC-MAIN-20200707173839-20200707203839-00058.warc.gz"} |
https://www.gradesaver.com/textbooks/math/geometry/CLONE-68e52840-b25a-488c-a775-8f1d0bdf0669/chapter-3-section-3-5-inequalities-in-a-triangle-exercises-page-160/36 | ## Elementary Geometry for College Students (6th Edition)
1-In a scalene triangle XYZ in which $\overline{ZW} bisects \angle XZY$ let us assume that ZW is perpendicular to segment XY. 2- segment ZW separates the $\triangle XYZ$ into two right triangles$( \triangle ZWY and \triangle ZWX )$ 3- these two triangle by our assumption they must be congruent by ASA since $\angle ZWY = \angle ZWX= 90^{\circ}, \overline{ZW}=\overline{ZW}$ by identity and $\angle YZW = \angle WZX$ by definition of angle bisector. 5- therefore $\angle Y = \angle X$ by CPCTC which contradicts the hypothesis, also $\overline{YZ}= \overline{XZ}$by CPCTC contradicts the hypothesis that triangle XYZ is a scalene triangle. 6- thus, the assumed statement must be false and segment ZW is not perpendicular to XY. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8954795598983765, "perplexity": 972.0314950923123}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-17/segments/1618039526421.82/warc/CC-MAIN-20210421065303-20210421095303-00469.warc.gz"} |
http://worldwidescience.org/topicpages/a/achieving+continuous+improvement.html | #### Sample records for achieving continuous improvement
1. Methods and Conditions for Achieving Continuous Improvement of Processes
2010-01-01
In the early twentieth century, the Taylor model improved, in a spectacular maner the efficiency of the production processes. This allowed obtaining high productivity by low-skilled workers, but used in large number in the execution of production. Currently this model is questioned by experts and was replaced by the concept of "continuous improvement". The first signs of change date from the '80s, with the apparition of quality circles and groups of operators on quality issues, principles whi...
2. Role of continual environmental performance improvement in achieving sustainability in uranium production
Although the term sustainable development is commonly used today, there is not yet a commonly accepted definition. Various ways of measuring sustainability have been proposed. To show how these issues are being effectively addressed in modern uranium developments, we will review some methods of defining the environmental component of sustainable development in the mining and mineral-processing sector. Environmental impacts associated with uranium extraction and processing in modern facilities are modest. Air and water emissions are well controlled. Waste materials are subject to comprehensive management programmes. The size of the impacted area is smaller than in other energy sectors, providing good opportunity to minimize land impact. Experience over the past three decades facilitated gradual, persistent, but cumulatively significant environmental improvements in the uranium production sector. Cameco's uranium mining and processing facilities exemplify these improvements. These improvements can be expected to continue, supporting our argument of Cameco's environmental sustainability. (author)
3. Achieving continuous improvement in reductions in foodborne listeriosis: A risk-based approach
Gram, Lone
2005-01-01
Listeria monocytogenes is a foodborne pathogen that can cause listeriosis, a severe disease that can lead to septicemia, meningitis, and spontaneous abortion. Ongoing efforts are needed to further reduce the incidence of listeriosis, due to its high mortality rate. The focus of this report is the...... use of a risk-based approach to identify strategies that will have the greatest impact on reducing foodborne listeriosis. A continuum of risk for listeriosis is observed in the human population, ranging from exquisitely sensitive groups, who are highly immunocompromised and at very high risk of...... minimize the likelihood that food will become contaminated by L. monocytogenes and to prevent the growth of the organism to high numbers. The Expert Panel identified three main strategies for ensuring continuous improvement in reducing foodborne listeriosis: (1) preventing contamination of foods with L...
4. Exemplary Care and Learning Sites: A Model for Achieving Continual Improvement in Care and Learning in the Clinical Setting
Ogrinc, Greg; Hoffman, Kimberly G.; Stevenson, Katherine M.; Shalaby, Marc; Beard, Albertine S.; Thörne, Karin E.; Coleman, Mary T.; Baum, Karyn D.
2016-01-01
Problem Current models of health care quality improvement do not explicitly describe the role of health professions education. The authors propose the Exemplary Care and Learning Site (ECLS) model as an approach to achieving continual improvement in care and learning in the clinical setting. Approach From 2008–2012, an iterative, interactive process was used to develop the ECLS model and its core elements—patients and families informing process changes; trainees engaging both in care and the improvement of care; leaders knowing, valuing, and practicing improvement; data transforming into useful information; and health professionals competently engaging both in care improvement and teaching about care improvement. In 2012–2013, a three-part feasibility test of the model, including a site self-assessment, an independent review of each site’s ratings, and implementation case stories, was conducted at six clinical teaching sites (in the United States and Sweden). Outcomes Site leaders reported the ECLS model provided a systematic approach toward improving patient (and population) outcomes, system performance, and professional development. Most sites found it challenging to incorporate the patients and families element. The trainee element was strong at four sites. The leadership and data elements were self-assessed as the most fully developed. The health professionals element exhibited the greatest variability across sites. Next Steps The next test of the model should be prospective, linked to clinical and educa tional outcomes, to evaluate whether it helps care delivery teams, educators, and patients and families take action to achieve better patient (and population) outcomes, system performance, and professional development. PMID:26760058
5. Achieving continuous professional development in higher education
Mandviwalla, Munir; Schuff, David; Ganju, Kartik
2015-01-01
Traditional higher education technology emphasizes knowledge transmission. In contrast, the Community platform presented in this paper follows a social approach that interleaves knowledge delivery with social and professional skills development, engaging with others, and personal growth. In this paper, we apply learning and complex adaptive systems theory to motivate and justify a continuous professional development model that improves higher education outcomes such as placement. The paper fo...
6. Partnership for Continuous Improvement
1990-01-01
The proceedings are presented of the sixth annual conference on quality control between NASA and its contractors. The emphasis is placed on a commitment to quality and excellence that guarantees mission success. A forum is provided for representatives from government, industry, and academia to exchange ideas and experiences, encouraging total quality performance that results in high quality products and services. Key points are highlighted from the presentations and activities are described that have resulted in a broad range of improvements in products and services from government, industry, and academia. Long term commitment to quality is an essential requirement that ensures future success. That commitment reinterates the dedication to excellence in space exploration and to national quality and productivity improvement.
7. Perspectives: The Continuous Improvement Trap
Arnold, David L.
2011-01-01
Accrediting agencies, legislators, pundits, and even higher educational professionals have become enamored with applying the language of continuous improvement to learning outcomes. The Southern Association of Colleges and Schools Commission on Colleges specifically uses the term "continuing improvement" in Core Standard 2.5, one of its…
8. Baseline budgeting for continuous improvement.
Kilty, G L
1999-05-01
This article is designed to introduce the techniques used to convert traditionally maintained department budgets to baseline budgets. This entails identifying key activities, evaluating for value-added, and implementing continuous improvement opportunities. Baseline Budgeting for Continuous Improvement was created as a result of a newly named company president's request to implement zero-based budgeting. The president was frustrated with the mind-set of the organization, namely, "Next year's budget should be 10 to 15 percent more than this year's spending." Zero-based budgeting was not the answer, but combining the principles of activity-based costing and the Just-in-Time philosophy of eliminating waste and continuous improvement did provide a solution to the problem. PMID:10387778
9. Improved continuity of reduced graphene oxide on polyester fabric by use of polypyrrole to achieve a highly electro-conductive and flexible substrate
Berendjchi, Amirhosein; Khajavi, Ramin; Yousefi, Ali Akbar; Yazdanshenas, Mohammad Esmail
2016-02-01
A flexible and highly conductive fabric can be applied for wearable electronics and as a pliable counter electrode for photovoltaics. Methods such as surface coating of fabrics with conductive polymers and materials have been developed, but the roughness of fabric is a challenge because it creates discontinuity in the coated layer. The present study first coated polyethylene terephthalate (PET) fabric with reduced graphene oxide sheets; RGO and then filled the gaps with polypyrrole (PPy). The samples were first dipped in graphene oxide (GO) and then reduced to RGO. They were next coated with PPy by in situ polymerization. The results showed that the presence of oxidative agent during synthesis of PPy oxidized the RGO to some extent on the previously RGO-coated samples. PPy was more uniform on samples pre-coated with RGO in comparison those coated with raw PET. The RGO-PPy coated samples exhibited 53% and 263% lower surface resistivity values than samples coated only with PPy and RGO, respectively. There was no significant difference between the tenacity of samples but the bending rigidity of samples increased. The RGO-PPy coated fabric displayed properties, such as excellent UV blocking (UPF = 73), antibacterial activity, improved electrochemical behavior and thermal stability which make it a multifunctional fabric.
10. Continuous improvement of pump seals
Pump seal reliability continues to be an area needing improvement and ongoing vigilance. Methods have been developed for identifying and assessing factors relating to seal performance, selecting the most relevant ones for a specific station, and then focusing on the most significant aspects and how to improve. Discussion invariably addresses maintenance practices, seal design, monitoring capabilities, operating conditions, transients, and pump and motor design. Success in reliability improvement requires ongoing dialogue among the station operators, pump manufacturers and seal designers. AECL CAN-seals lead the nuclear industry in reliability and seal life. They effectively save operators millions of dollars in outage time and person-rem. This paper describes some of the significant developments in AECL's ongoing program in seal R and D, as well as recent new installations following the most demanding seal qualification programs to date. (author)
11. Sustaining motivation for continuous improvement
Jørgensen, Frances; Kofoed, Lise Busk
2007-01-01
The objective of this article is to explore possibilities for improving motivation for participation in Continuous Improvement (CI). Due to a number of issues, for example, challenges with measuring outcomes of CI activities on performance, the inherent slower, incremental rather than big bang...... nature of CI, and the perception of CI as being something done in addition to normal job responsibilities, motivation for participation may dwindle over time. Because CI is dependent on active participation of all members of the organization, including shop floor workers, sustaining motivation for CI...... activities is an important issue for managers. The paper begins with a short description of CI, with an emphasis on barriers to successful implementation cited in the literature. Thereafter, a number of widely-acknowledged-albeit perhaps somewhat dated-theories of motivation are explored in relation to the...
12. Quick and continuous improvement through kaizen blitz.
McNichols, T; Hassinger, R; Bapst, G W
1999-05-01
It is our objective to provide you with a step-by-step approach to conducting a kaizen blitz within two days and describe how to achieve dramatic performance improvement with employee buy-in through this process. Kaizen blitz has been used dozens of times by the authors, and in some instances the same area has been blitzed as many as four times, with significant improvements each and every time. Employees have even taken it on themselves to conduct informal blitzes as a continuing improvement effort after a formal blitz has been conducted in their area. Blitzes can succeed in a variety of environments. The morning after the employees of one company attended this presentation, they self initiated a mini-blitz and discovered opportunities for improvement that they enthusiastically presented to management. PMID:10387775
13. KEY FACTORS FOR A CONTINUOUS IMPROVEMENT PROCESS
Hector Ricardo Formento
2013-11-01
Full Text Available The goal of this work was to examine the content of continuous improvement strategies, taking into account the important role they play in building competitiveness. This paper argues that several specific issues must be taken into account in order to reach successful outcomes. This work starts with a literature review on the matter. On this basis, we designed a survey administered to a group of 30 large companies, each of which is renowned leader in Argentina. Finally, we compared the development of continuous improvement process in companies with very effective results and with scarce results. Differences that emerged from this comparison enabled us to identify critical factors for achieving a successful improvement process. As there are no recent researches on continuous improvement programs in Argentina, this paper contributes to recognizing and systematizing what has been done, comparing it with theoretical framework and uncovering research gaps for future studies. However, further research must confirm these findings and move forward on the analysis of intangible factors, like: internal communications, climate, culture, self reflexion, consensus, etc.
14. Continuous Improvement in Schools: Understanding the Practice
Anderson, Stephen; Kumari, Roshni
2009-01-01
This article investigates conceptually and practically what it means for schools to engage in the practice of continuous improvement. The analysis draws upon prior research and discussion to predict core elements of the practice of continuous improvement in schools. The predictions are then applied to a case study of continuous improvement efforts…
15. CTE's Focus on Continuous Improvement
Foster, John; Kelley, Patricia; Pritz, Sandy; Hodes, Carol
2011-01-01
Just one of the ways career and technical education (CTE) is revamping its image is through increased attention to data-driven instructional techniques as a means of improving and focusing instruction on what matters most. Accountability and data have increasingly become a core focus of research, news, and commentary about education in recent…
16. Continuous Improvement and Collaborative Improvement: Similarities and Differences
Middel, Rick; Boer, Harry; Fisscher, Olaf
2006-01-01
A substantial body of theoretical and practical knowledge has been developed on continuous improvement. However, there is still a considerable lack of impirically grounded contributions and theories on collaborative improvement, that is, continuous improvement in an interorganizational setting. The...... CO-IMPROVE project investigated whether and how the concept of continuous improvement can be extended and transferred to such settings. The objective of this article is ti evaluate the CO-IMPROVE research findings in view of existing theories on continuous innovation. The article investigates the...... similarities and differences between key components of continuous and collaborative improvement by assessing what is specific for continuous improvement, what for collaborative improvement, and where the two areas of application meet and overlap. The main conclusions are that there are many more similarities...
17. Teacher Research as Continuous Process Improvement
Ellis, Charles; Castle, Kathryn
2010-01-01
Purpose: Teacher research (inquiry) has been characterized as practice improvement, professional development and action research, among numerous names and descriptions. The purpose of this paper is to support the case that teacher research is also a form of quality improvement known as continuous process improvement (CPI).…
18. Improving Student Achievement in Math and Science
Sullivan, Nancy G.; Hamsa, Irene Schulz; Heath, Panagiota; Perry, Robert; White, Stacy J.
1998-01-01
As the new millennium approaches, a long anticipated reckoning for the education system of the United States is forthcoming, Years of school reform initiatives have not yielded the anticipated results. A particularly perplexing problem involves the lack of significant improvement of student achievement in math and science. Three "Partnership" projects represent collaborative efforts between Xavier University (XU) of Louisiana, Southern University of New Orleans (SUNO), Mississippi Valley State University (MVSU), and the National Aeronautics and Space Administration (NASA), Stennis Space Center (SSC), to enhance student achievement in math and science. These "Partnerships" are focused on students and teachers in federally designated rural and urban empowerment zones and enterprise communities. The major goals of the "Partnerships" include: (1) The identification and dissemination of key indices of success that account for high performance in math and science; (2) The education of pre-service and in-service secondary teachers in knowledge, skills, and competencies that enhance the instruction of high school math and science; (3) The development of faculty to enhance the quality of math and science courses in institutions of higher education; and (4) The incorporation of technology-based instruction in institutions of higher education. These goals will be achieved by the accomplishment of the following objectives: (1) Delineate significant ?best practices? that are responsible for enhancing student outcomes in math and science; (2) Recruit and retain pre-service teachers with undergraduate degrees in Biology, Math, Chemistry, or Physics in a graduate program, culminating with a Master of Arts in Curriculum and Instruction; (3) Provide faculty workshops and opportunities for travel to professional meetings for dissemination of NASA resources information; (4) Implement methodologies and assessment procedures utilizing performance-based applications of higher order
19. Fibromyalgia syndrome: Can improvement be achieved?
2012-06-01
Full Text Available Research Institute of Rheumatology, Russian Academy of Medical Sciences, Moscow The paper gives data on the prevalence, pathogenesis, clinical manifestations, and treatment of fibromyalgia (FM syndrome. It is stated that the ratio of all clinical symptoms of FM syndrome should be borne in mind when treating patients with this disease. Various specialists should be attracted to the treatment of these patients. Psychotropic medications that are prescribed by a psychiatrist are indicated where there is a preponderance of psychological disorders; the duration of this therapy is variable, but not more than 2—3 months. Most patients need proper analgesia, improved sleep quality and duration, and diminished fatigability that frequently leads to lower (none working capacity. Pregabalin (lyrica promptly suppresses the major manifestations of FM; the onset of its action is seen just after one week of treatment; the use of the drug may be continued as long as it is effective and safe.
20. Fibromyalgia syndrome: Can improvement be achieved?
2012-01-01
Full Text Available Research Institute of Rheumatology, Russian Academy of Medical Sciences, Moscow The paper gives data on the prevalence, pathogenesis, clinical manifestations, and treatment of fibromyalgia (FM syndrome. It is stated that the ratio of all clinical symptoms of FM syndrome should be borne in mind when treating patients with this disease. Various specialists should be attracted to the treatment of these patients. Psychotropic medications that are prescribed by a psychiatrist are indicated where there is a preponderance of psychological disorders; the duration of this therapy is variable, but not more than 2—3 months. Most patients need proper analgesia, improved sleep quality and duration, and diminished fatigability that frequently leads to lower (none working capacity. Pregabalin (lyrica promptly suppresses the major manifestations of FM; the onset of its action is seen just after one week of treatment; the use of the drug may be continued as long as it is effective and safe.
1. Improving mental health outcomes: achieving equity through quality improvement
Poots, Alan J; Green, Stuart A.; Honeybourne, Emmi; Green, John; Woodcock, Thomas; Barnes, Ruth; Bell, Derek
2014-01-01
Objective To investigate equity of patient outcomes in a psychological therapy service, following increased access achieved by a quality improvement (QI) initiative. Design Retrospective service evaluation of health outcomes; data analysed by ANOVA, chi-squared and Statistical Process Control. Setting A psychological therapy service in Westminster, London, UK. Participants People living in the Borough of Westminster, London, attending the service (from either healthcare professional or self-r...
2. Human Resource Management for Continuous Improvement
Jørgensen, Frances; Laugen, Bjørge; Boer, Harry
2006-01-01
The objective of this paper is to investigate the relationship between HRM practices and Continuous Improvement (CI) activities in order to gain an understanding of how the HRM function may be utilized to improve CI implementation success, and consequently, organizational performance. The paper i...
3. Human Resource Management for Continuous Improvement
Jørgensen, Frances; Laugen, Bjørge Timenes; Boer, Harry
2007-01-01
This paper investigates the relationship between HRM practices and Continuous Improvement (CI) activities in order to gain an understanding of how the HRM function may be utilized to improve CI implementation success, and consequently, company performance. The paper begins with a brief review of ...
4. Continue Service Improvement at CERN Computing Centre
Barroso Lopez, M.; Everaerts, L.; Meinhard, H.; Baehler, P.; Haimyr, N.; Guijarro, J. M.
2014-06-01
Using the framework of ITIL best practises, the service managers within CERN-IT have engaged into a continuous improvement process, mainly focusing on service operation. This implies an explicit effort to understand and improve all service management aspects in order to increase efficiency and effectiveness. We will present the requirements, how they were addressed and share our experiences. We will describe how we measure, report and use the data to continually improve both the processes and the services being provided. The focus is not the tool or the process, but the results of the continuous improvement effort from a large team of IT experts providing services to thousands of users, supported by the tool and its local team. This is not an initiative to address user concerns in the way the services are managed but rather an on-going working habit of continually reviewing, analysing and improving the service management processes and the services themselves, having in mind the currently agreed service levels and whose results also improve the experience of the users about the current services.
5. Continue service improvement at CERN computing centre
Using the framework of ITIL best practises, the service managers within CERN-IT have engaged into a continuous improvement process, mainly focusing on service operation. This implies an explicit effort to understand and improve all service management aspects in order to increase efficiency and effectiveness. We will present the requirements, how they were addressed and share our experiences. We will describe how we measure, report and use the data to continually improve both the processes and the services being provided. The focus is not the tool or the process, but the results of the continuous improvement effort from a large team of IT experts providing services to thousands of users, supported by the tool and its local team. This is not an initiative to address user concerns in the way the services are managed but rather an on-going working habit of continually reviewing, analysing and improving the service management processes and the services themselves, having in mind the currently agreed service levels and whose results also improve the experience of the users about the current services.
6. Continuous supply chain collaboration: Road to achieve operational excellence
N. Senthil Kumar
2011-04-01
Full Text Available Supply chain management (SCM is becoming critical as firms recognize that competition is shifting from company versus company to supply chain versus supply chain. In the present competitive scenario, the fierce competition has driven most companies to seek for means of enhancing performance beyond their four wall boundaries. The firm’s ability in collaborating with its upstream and downstream partners determines its success in attaining better performance with supply chain collaboration; a firm is able to serve fragmented markets in which end customers require more product varieties and availability with shorter product life cycle and, at the same time, lower supply chain costs. This paper introduces the framework of continuous supply chain collaboration (CSCC, which extends the traditional frame of reference in strategic sourcing from a supplier centric to a supply-chain-scope as continuous improvement efforts to enhance the customer satisfaction. CSCC practices are rather exceptional, yet CSCC is believed to be the single most comprehensive framework for attaining operational excellence.
7. CONTINUOUS IMPROVEMENT THROUGH INTEGRATION OF QUALITY TOOLS
2006-01-01
The relationship between major quality tools such as quality function development (QFD),failure mode and effects analysis (FMEA), design of experiments (DOE) and statistical process control (SPC) is analyzed through an extensive review of the literature and the concurrent quality engineering philosophy, and a basic structure for the integration of quality tools is presented. An integrated quality management system (IQMS) is developed using C++ Builder, nmning in the Windows 2000 Server environment with the basic internet connections, and SQL Server 2000 as the platform for developing the database. An illustrative example applying IQMS to the continuous quality improvement for a crane equipment manufacturing is reported. The result shows that the application of IQMS can optimize the process of design and manufacturing, shorten the cycle time of product, reduce the cost, and realize quality improvement continuously. The proposed integrated framework with IQMS is believed to be applicable to continuous quality improvement in many manufacturing companies.
8. Health Care Improvement and Continuing Interprofessional Education: Continuing Interprofessional Development to Improve Patient Outcomes
Wilcock, Peter M.; Janes, Gillian; Chambers, Alison
2009-01-01
Health care improvement and continuing professional education must be better understood if we are to promote continuous service improvement through interprofessional learning in the workplace. We propose that situating interprofessional working, interprofessional learning, work-based learning, and service improvement within a framework of social…
9. INSIDE CONTINUOUS IMPROVEMENT - A LITERATURE REVIEW
Daniel Indarto Prajogo
2000-01-01
Full Text Available This paper discusses the concept of continuous improvement (CI by looking beyond what traditionally highlighted in literature concerning continuous improvement or Total Quality Management (TQM. The primary argument put forwarded in the discussion is that despite the undeniable positive results from CI practices, the way these activities are implemented, however, will lead to most programs becoming self-limiting. It needs to be asserted here that this paper is not intended to despise CI, rather, its purpose is limited only to provide a balance on the prevailing positive views toward CI.
10. Software Maintenance Management Evaluation and Continuous Improvement
April, Alain
2008-01-01
This book explores the domain of software maintenance management and provides road maps for improving software maintenance organizations. It describes full maintenance maturity models organized by levels 1, 2, and 3, which allow for benchmarking and continuous improvement paths. Goals for each key practice area are also provided, and the model presented is fully aligned with the architecture and framework of software development maturity models of CMMI and ISO 15504. It is complete with case studies, figures, tables, and graphs.
11. The Continuous Improvement Model: A K-12 Literacy Focus
Brown, Jennifer V.
2013-01-01
The purpose of the study was to determine if the eight steps of the Continuous Improvement Model (CIM) provided a framework to raise achievement and to focus educators in identifying high-yield literacy strategies. This study sought to determine if an examination of the assessment data in reading revealed differences among schools that fully,…
12. Continuous Improvement in State Funded Preschool Programs
Jackson, Sarah L.
2012-01-01
State funded preschool programs were constantly faced with the need to change in order to address internal and external demands. As programs engaged in efforts towards change, minimal research was available on how to support continuous improvement efforts within the context unique to state funded preschool programs. Guidance available had…
13. A Typology of Continuous Improvement Implementation Processes
Rijnders, Sander; Boer, Harry
2004-01-01
This article presents a typology of continuous improvement (CI) implementation processes. The typology is based on an empirical study of 26 companies engaged in the implementation of CI. The data underpinning the typology was collected through retrospective interviews guided by a semi...
14. Human Resource Development's Contribution to Continuous Improvement
Jørgensen, Frances; Hyland, Paul
Continuous Improvement (CI) is an approach to organizational change that requires active involvement of skilled and motivated employees, which implies an important role for HRD practitioners. The findings from a literature review and a survey of 168 Danish manufacturing companies indicate however...
15. Human Resource Development's Contribution to Continuous Improvement
Jørgensen, Frances; Hyland, Paul
2007-01-01
Continuous Improvement (CI) is an approach to organizational change that requires active involvement of skilled and motivated employees, which implies an important role for HRD practitioners. The findings from a literature review and a survey of 168 Danish manufacturing companies indicate however...
16. Continuous improvement: A win-win process
The strategies used within PanCanadian Petroleum Limited's production division to successfully introduce the continuous improvement (CI) process are discussed. Continuous improvement is an operating philosophy and management style which allows all employees to participate in and improve the way an organization performs its day-to-day business. In the CI work environment the supervisor's traditional role changes from one of monitoring and controlling, to one of inspiring, motivating and leading people by communicating a clear vision. Employees at all levels in the work environment are organized into teams and armed with a good working knowledge of the problem-solving tools which allow them to pursue and implement improvement initiatives. The outcome of the process is an ongoing win-win situation for both PanCanadian and its people. Employees are gaining more trust, eliminating job irritants, and enjoying their work in a team environment. The company is benefiting through increased production, improved safety and reduced operating expenses, thanks to the many innovative ideas introduced by employees. 4 refs
17. KEY FACTORS FOR A CONTINUOUS IMPROVEMENT PROCESS
Hector Ricardo Formento; Franco Javier Chiodi; Fernando Juan Cusolito; Lucas Ariel Altube; Sebastian Pablo Gatti
2013-01-01
The goal of this work was to examine the content of continuous improvement strategies, taking into account the important role they play in building competitiveness. This paper argues that several specific issues must be taken into account in order to reach successful outcomes. This work starts with a literature review on the matter. On this basis, we designed a survey administered to a group of 30 large companies, each of which is renowned leader in Argentina. Finally, we compared the develop...
18. Continuous Quality Improvement: Implementation and Sustainability
Yella, Gilbert Ncheh; Atem, Tongwa Ivo
2007-01-01
As the philosophy of doing business shift from sell what you can produce to produce what you can sell so do the customers’ specification continuously become a vital tool during product development process, hence increasing the volatility of the business environment. The objective of this thesis is to thoroughly review literature to be supported by cases why most companies fail in sustaining improvement programs then map out a pathway that will leads to successful implementation. A series of r...
19. Strategic School Funding for Improved Student Achievement
Chambers, Jay G.; Brown, James R.; Levin, Jesse; Jubb, Steve; Harper, Dorothy; Tolleson, Ray; Manship, Karen
2010-01-01
This article features Strategic School Funding for Results (SSFR) project, a new joint initiative of the American Institutes for Research (AIR) and Pivot Learning Partners (PLP) aimed at improving school finance, human resources, and management systems in large urban school districts. The goal of the project is to develop and implement more…
20. Achieving Improved Ohmic Confinement via impurity injection
Improved Ohmic Confinement (IOC) was obtained in ASDEX after a modification of the divertors that allowed a larger (deuterium and impurity) backflow from the divertor chamber. The quality of IOC depended crucially on the wall conditions, i.e. IOC was best for uncovered stainless steel walls and vanished with boronization. Furthermore, IOC was found only in deuterium discharges. These circumstances led to the idea that IOC correlates with the content of light impurities in the plasma. To substantiate this working hypothesis, we present observations in deuterium discharges with boronized wall conditions into which various impurities have been injected with the aim to induce IOC conditions. The remainder of this contribution is organized according to the following lines: Firstly, the plasma behaviour in typical IOC discharges is characterized. Secondly, injection experiments with the low-Z impurities nitrogen and neon as well as with the high-Z impurities argon and krypton are discussed. Then, we concentrate on optimized neon puffing that yields the best confinement results which are similar to IOC conditions. Finally, these results are compared with experiments in other tokamaks and some conclusions are drawn about the effects of the impurity puffing on both, the central and the edge plasma behaviour. (author) 9 refs., 2 figs
1. Achieving improved ohmic confinement via impurity injection
Improved Ohmic Confinement (IOC) was obtained in ASDEX after a modification of the divertors that allowed a larger (deuterium and impurity) backflow from the divertor chamber. The quality of IOC depended crucially on the wall conditions, i.e. IOC was best for uncovered stainless steels walls and vanished with boronization. Furthermore, IOC was found only in deuterium discharges. These circumstances led to the idea that IOC correlates with the content of light impurities in the plasma. To substantiate this working hypothesis, we present observations in deuterium discharges with boronized wall conditions into which various impurities have been injected with the aim to induce IOC conditions. Firstly, the plasma behaviour in typical IOC discharges is characterized. Secondly, injection experiments with the low-Z impurities nitrogen and neon as well as with the high-Z impurities argon and krypton are discussed. Then, we concentrate on optimized neon puffing that yields the best confinement results which are similar to IOC conditions. Finally, these results are compared with eperiments in other tokamaks and some conclusions are drawn about the effects of the impurity puffing on both, the central and the edge plasma behaviour. (orig.)
2. Continuous improvement: A win... win process
Implementing a continuous improvement (CI) process within PanCanadian's oil and gas production operations might have been a simple assignment if one were not also trying to capture the hearts and imaginations of the people in a changing work environment. Meeting the challenge is resulting in big payoffs to both the organization and its people. The plan used within the Company's Production Division to successfully introduce the CI process is discussed. A brief insight is provided on the process philosophy, with emphasis placed on planning, training and coaching used to launch the process. Also reviewed at length are the impediments to change and the challenges faced when changing an organization's culture. In a CI work environment, the supervisor's traditional role changes from one of monitoring and controlling to one of inspiring, motivating and leading people by communicating a clear vision. Employees at all levels in the work environment are organized into teams and armed with a good working knowledge of the problem solving tools which allow them to pursue and implement improvement initiatives. The outcome of the process is an ongoing 'win-win' situation for both the Company and its people. Employees are gaining more trust, eliminating job irritants and enjoying their work more in a team environment. The Company is winning through increased production, improved safety and reduced operating expenses, thanks to many innovative ideas which the employees have implemented. 4 refs
3. Achieving optimal diabetic control in adolescence: the continuing enigma.
McConnell, E M; Harper, R; Campbell, M; Nelson, J K
2001-01-01
The transition from childhood through adolescence to adulthood is a difficult stage, particularly for patients with type 1 diabetes. The yearning for autonomy and independence, as well as the hormonal changes around the time of puberty, can manifest in poor glycaemic control. The focus on diet and weight increases the prevalence of eating disorders, compounding the difficulties in supervising diabetes patients. This can be exacerbated by the realisation that hyperglycaemia induces weight loss and the use of this knowledge to further manipulate diabetes control to gain a desired body image. The management of adolescents with type 1 diabetes is therefore challenging and requires close collaboration between psychological medicine and diabetes teams. This review describes the difficulties frequently encountered, with a description of four cases illustrating these points. Case 1 demonstrates the problem of needle phobia in a newly diagnosed patient with type 1 diabetes leading to persistent hyperglycaemia, the recognition of weight loss associated with this and the development of bulimia. The patient's overall management was further complicated by risk-taking behaviour. By the age of 24 years, she has developed diabetic retinopathy and autonomic neuropathy and continues to partake in risk-taking behaviour. Case 2 illustrates how the lack of parental support shortly after the development of type 1 diabetes led to poor glycaemic control and how teenagers often omit insulin to accommodate lifestyle and risk-taking behaviour. Case 3 further exemplifies the difficulty in managing patients with needle phobia and the fear of hypoglycaemia. Case 4 adds further weight to the need for parental support and the impact of deleterious life events on glycaemic control by manipulation of insulin dosage. PMID:11241893
4. Continuous improvement based on learning capacity of petroleum industry
Filho, C.A.; Silva, E.N.C.; Rodriguez, M.V.R.; Quelhas, O.L.G. [Univ. Federal Fluminense, Rio de Janeiro (Brazil)
2004-07-01
Knowledge management is one of the newest strategies for organizations to improve their productivity. Oil companies seeking business sustainability are faced with the challenge of continuously improving their operations. This paper emphasized that in order to improve, companies must gain valuable experience through planning, perseverance, commitment and processes that accumulate results. It presented a visual methodology, based on symbolisms and key words, which is intended to facilitate the assimilation of the continuous improvement program structure from knowledge management. The concepts of Garvin, Nonaka and Takeuchi were presented as means for improving the capacity of an organization seeking a learning atmosphere through the prioritization of actions to facilitate team activities and accumulate knowledge in the individual. It was shown that Japanese companies in the production sector have used 4 processes of knowledge conversion: socialization, exteriorization, internalization and their combinations. The Garvin concept has proposed that continuous improvement of an organization would be more positive if the companies learnt a basic lesson. This paper articulated resulting observations from Garvin and from Nonaka and Takeuchi theories and proposed recommendations based on symbolism for identifying action strategies and achievement objectives. Issues regarding working conditions and the influence on learning were discussed along with different ways to transfer knowledge in terms of competencies and skills. 14 refs., 7 figs.
5. Continual Improvement In Small Soaps Company
Borget Alfred Anoye
2015-08-01
Full Text Available Abstract In this paper using quality management tools we track root causes and principal causes of the rising manufacturing cost of the bar soaps and propose solution to solve the problem. First we identify and analyze the roots causes of problem with the Fishbone Diagram. We use multivoting approach to reduce roots causes to main causes from which we identify classify and analyze principal causes using the Pareto Diagram. We then perform a deep analysis of these principal causes using the 5 whys analysis technique. Three principal causes were found amp61480high level of overtime poor machine performance and poor employees performanceamp61481 and were weighing 55 of the problem. For that reason working on these areas was necessary to address the problem of the rising manufacturing cost of the bar soaps. With the result we then use the PDCA 7 steps of TQM method to solve the problem of the rising manufacturing cost by testing whether expanding production capacity leads to performance improvements of these areas. We decide to expand production capacity by adding two more machine groups. Six months after implementation of the proposed solution the result shows an enhanced workload and schedule an increased production capacity an elimination of the overtime issue an increased machines performance and an improved workers performance. Two main savings were achieved as wage costs and maintenance costs. As a result while competitors bar soaps prices increased the company bar soaps price decreased by 50 making the company bar soaps more attractive on market as this performance permitted the company to apply price reduction at the retailer level.
6. Organisational learning: A tool for continuous improvement of the organization
We are used to hear a success company in today's world is not possible unless a continuous improvement is developed. How can we be successful in the nuclear plant? We have to achieve safety for workers, people and environment in the first step, and for the second step availability and reliability for systems and components to avoid failure of components that could reduce availability. The aim is to search for new measures to reach this way. One of the improvements implemented in the plants to improve continuously was mainly Operating Experience activities, which was based in event analysis in the plants, causes identification, and to implement corrective actions. For External Operating Experience the aim was to learn from others to avoid occurrence of events in our plants. This was the lessons learned from Three Mile Island event. This was the learning process implemented so far, to get a continuous improvement. So far, the developed capabilities for process improvement follow the Operating Experience process that could be considered classical and will be revitalized nowadays. (Author)
7. Science Achievement for All: Improving Science Performance and Closing Achievement Gaps
Jackson, Julie K.; Ash, Gwynne
2012-01-01
This article addresses the serious and growing need to improve science instruction and science achievement for all students. We will describe the results of a 3-year study that transformed science instruction and student achievement at two high-poverty ethnically diverse public elementary schools in Texas. The school-wide intervention included…
8. Improvements in Interval Time Tracking and Effects on Reading Achievement
Taub, Gordon E.; McGrew, Kevin S.; Keith, Timothy Z.
2007-01-01
This study examined the effect of improvements in timing/rhythmicity on students' reading achievement. 86 participants completed pre- and post-test measures of reading achievement (i.e., Woodcock-Johnson III, Comprehensive Test of Phonological Processing, Test of Word Reading Efficiency, and Test of Silent Word Reading Fluency). Students in the…
9. Achieving higher capability maturity in construction process improvement
Keraminiyage, Kaushal; Amaratunga, Dilanthi; Haigh, Richard
2005-01-01
Process improvement has been identified as one of the potential mechanisms to achieve the desired performance improvements within the UK construction industry. In addition, it has further been recognised the importance of learning construction process improvement lessons from other industry examples. Software industry has exemplified a successful implementation of a process improvement strategy, based on the Capability Maturity Model (CMM) which evaluate the capabilities and maturities of org...
10. Does Children's Academic Achievement Improve when Single Mothers Marry?
Wagmiller, Robert L., Jr.; Gershoff, Elizabeth; Veliz, Philip; Clements, Margaret
2010-01-01
Promoting marriage, especially among low-income single mothers with children, is increasingly viewed as a promising public policy strategy for improving developmental outcomes for disadvantaged children. Previous research suggests, however, that children's academic achievement either does not improve or declines when single mothers marry. In this…
11. Case Studies in Continuous Process Improvement
Mehta, A.
1997-01-01
This study focuses on improving the SMT assembly process in a low-volume, high-reliability environment with emphasis on fine pitch and BGA packages. Before a process improvement is carried out, it is important to evaluate where the process stands in terms of process capability.
12. [Organizational capacity for continuous improvement of health services].
Saturno-Hernández, Pedro J; Hernández-Avila, Mauricio; Magaña-Valladares, Laura; Garcia-Saisó, Sebastián; Vertiz-Ramírez, José de Jesús
2015-01-01
While the Mexican health system has achieved significant progress, as reflected in the growing improvement in population health, heterogeneity in the quality of services and its impact on health in different population groups is still a challenge. The costs or poor quality represent about 20 to 40% of the health system's expenditure. We need to develop organizational capacity to implement quality management systems in order to identify, evaluate, prevent and eventually overcome the health system's challenges. A competency-based comprehensive strategy for training human resources is proposed including undergraduate and graduate education as well as continuing education, which will contribute to improve the quality function at the various levels of responsibility in the health system. The proposed strategy responds to the context of the Mexican health system, but it could be adapted to other systems and contexts. PMID:26302131
13. Quality improvement of continuously cast round billets
F. Chowaniec
2008-07-01
Full Text Available Paper is focused on the observation of the conditions causing defects origin in continuously cast billets in the first phase of solidification and shell formation in the mould. Work is also focused on the area of casting failures. Experiences were aimed at steel preparation for casting from the viewpoint of desoxidation and modification of inclusions, facility influence on solidification and formation of shell, influence of the taper of the mould, and on vibrations influence and origin within primary cooling system – oscillation mechanism – mould. The method of measurement was tested, incl. the analysis of acoustic spectrum for phenomena assessment within continuous casting. Conclusions resulted in modification and changes of shapes of moulds, incl. casting technology of round billets.
14. Metacognitive Training in Professional Development Can Improve and Sustain Student Achievement
Phillips, Jeffrey A; Clemmer, Katharine W
2016-01-01
Secondary school students in the United States continue to underachieve in mathematics and science. Improving teacher quality is a core component of improving student achievement. Here we report on a professional development program, the MAST System, that develops the knowledge and skills for teaching mathematics, including metacognitive knowledge and regulation. In this cognitive apprenticeship program, teachers learn to plan, evaluate and adjust to improve student engagement and achievement. Central is the metacognitive practice of defense of instruction. By practicing this reflective approach, teachers become adaptive experts, able to innovate in the classroom. During the two-year intervention, the MAST System resulted in large increases in the California Standards Test mathematics scores, compared to both the district and the state. In addition, improvement continued for several years after the intervention was completed. This continued improvement in student scores indicated that the teachers and schools...
15. Spent fuel transport: A continuous improvement
Full text: Since the 70's, approximately 30,000 tons of spent fuel has been safely transported to COGEMA-La Hague plant from French Nuclear Power Plants (NPP) and foreign nuclear operators involving more than 5,500 shipments. COGEMA LOGISTICS made this possible by the continuous development of adapted transport casks duly licensed according to the regulations in force, the procurement of dedicated transport equipment such as wagons, trucks and ships, and an efficient transport organization providing a comprehensive door-to-door service. New markets are under development implying new routes and organization. This paper is aimed at presenting our approach to meet the future challenges. (author)
16. Heterogeneity Improves Cooperation in Continuous Snowdrift Game
ZHONG Li-Xin; QIU Tian; XU Jiang-Rong
2008-01-01
We study the networking effects on the population divergence and the increased level of cooperation in the continuous snowdrift game (CSG). In the regular world, limited interaction inhibits the occurrence of evolutionary branching. The formation of clusters defends the intermediate-investors from intruding by high- or low-investors. In a rewired network, the collective behaviour is related to the rewiring rules. A linear relationship I = ασ + b between the average investment and the standard deviation of the degree distribution is found.
17. New Directions in Social Psychological Interventions to Improve Academic Achievement
Wilson, Timothy D.; Buttrick, Nicholas R.
2016-01-01
Attempts to improve student achievement typically focus on changing the educational environment (e.g., better schools, better teachers) or on personal characteristics of students (e.g., intelligence, self-control). The 6 articles in this special issue showcase an additional approach, emanating from social psychology, which focuses on students'…
18. IMPLEMENTASI ???CONTINUOUS IMPROVEMENT MINDSET DAN CHANGE MANAGEMENT??? DALAM ORGANISASI BISNIS
Payangan, Otto Randa
2014-01-01
This paper explains that the "Continuous Improvement Mindset and Change Management" is very important to implement in support of an organization's business performance improvement on ongoing basis. The goal in developing the "Continuous Improvement Mindset and Change Management" is, strongly influenced by changes in a highly dynamic environment and the increasing level of dynamic competition, in creating products and services excellence. The approach used in the realization of Continuous Imp...
19. Continuous quality improvement of colorectal cancer screening
2013-01-01
Quality assurance is a key issue in colorectal cancer screening, because effective screening is able to improve primary prevention of the cancer. The quality measure may be described in terms:how well the screening test tells who truly has a disease (sensitivity) and who truly does not have a disease (specificity). This paper raises concerns about identification of the optimal screening test for colorectal cancer. Colonoscopy vs flexible sigmoidoscopy in colorectal cancer screening has been a source of ongoing debate. A multicentre randomised controlled trial comparing flexible sigmoidoscopy with usual care showed that flexible sigmoidoscopy screening is able to diminish the incidence of distal and proximal colorectal cancer, and also mortality related to the distal colorectal cancer. However, colonoscopy provides a more complete examination and remains the more sensitive exam than flexible sigmoidoscopy. Moreover, colonoscopy with polypectomy significantly reduces colorectal cancer incidence and colorectal cancer-related mortality in the general population. The article considers the relative merits of both methods and stresses an ethical aspect of patient’s involvement in decision-making. Patients should be informed not only about tests tolerability and risk of endoscopy complications, but also that different screening tests for bowel cancer have different strength to exclude colonic cancer and polyps. The authorities calculate effectiveness and costs of the screening tests, but patients may not be interested in statistics regarding flexible sigmoidoscopy screening and from an ethical point of view, they have the right to chose colonoscopy, which is able to exclude a cancer and precancerous lesions in the whole large bowel.
20. La Hague Continuous Improvement Program: Enhancement of the Vitrification Throughput
The vitrification of high-level liquid waste produced from nuclear fuel reprocessing has been carried out industrially for over 25 years by AREVA/COGEMA, with two main objectives: containment of the long lived fission products and reduction of the final volume of waste. At the 'La Hague' plant, in the 'R7' and 'T7' facilities, vitrified waste is obtained by first evaporating and calcining the nitric acid feed solution-containing fission products in calciners. The product-named calcinate- is then fed together with glass frit into induction-heated metallic melters to produce the so-called R7/T7 glass, well known for its excellent containment properties. Both facilities are equipped with three processing lines. In the near future the increase of the fuel burn-up will influence the amount of fission product solutions to be processed at R7/T7. As a consequence, in order to prepare these changes, it is necessary to feed the calciner at higher flow-rates. Consistent and medium-term R and D programs led by CEA (French Atomic Energy Commission, the AREVA/COGEMA's R and D and R and T provider), AREVA/COGEMA (Industrial Operator) and AREVA/SGN (AREVA/COGEMA's Engineering), and associated to the industrial feed back of AREVA/COGEMA operations, have allowed continuous improvement of the process since 1998: - The efficiency and limitation of the equipment have been studied and solutions for technological improvements have been proposed whenever necessary, - The increase of the feeding flow-rate has been implemented on the improved CEA test rig (so called PEV, Evolutional Prototype of Vitrification) and adapted by AREVA/SGN for the La Hague plant using their modeling studies; the results obtained during this test confirmed the technological and industrial feasibility of the improvements achieved, - After all necessary improved equipments have been implemented in R7/T7 facilities, and a specific campaign has been performed on the R7 facility by AREVA/COGEMA. The flow-rate to the
1. CONTINUOUS IMPROVEMENT PRACTICE IN LARGE ENTERPRISES: STUDY RESULTS
2015-03-01
Full Text Available Continuous improvement is indispensable for ensuring the company's development and its survival on the constantly changing global market. Continuous improvement is particularly important in the quality and production management systems. A company should deliver a product compliant with a client's requirements in a specified time and at an appropriate price. That is why, continuous improvement refers to different areas of an organization's functioning and it is an integral part of Lean Manufacturing. This article presents the results of the study conducted in production enterprises on a limited area. The aim of the study was the assessment of the implementation of continuous improvement in Lean Manufacturing, and, in particular, employees' involvement in the problem identification and in reporting improvements as well as the way of motivating employees to involve themselves. The authors also tried to identify the factors influencing the elements of a continuous improvement system.
2. Implementing Continuous Improvement Management (CIM) in the Public Schools.
Borgers, William E.; Thompson, Tommy A.
This book traces the restructuring of a Texas school district that moved from management by coercion to continuous improvement for quality. In 1990, the Dickinson Independent School District (Texas) began implementation of Continuous Improvement Management (CIM), based on the teachings of W. Edwards Deming, William Glasser, and J. M. Juran.…
3. [Continuous nursing education to improve the quality of health care].
Fumić, Nera; Marinović, Marin; Brajan, Dolores
2014-10-01
Health care and today's medical and technical achievements and approved standards of treatment provide comprehensive quality, safety and traceability of medical procedures respecting the principles of health protection. Continuous education improves the quality of nursing health care and increases the effectiveness of patient care, consequently maintaining and enhancing patient safety. Patient health problems impose the need of appropriate, planned and timely nursing care and treatment. In providing quality nursing care, attention is focused on the patient and his/her needs in order to maintain and increase their safety, satisfaction, independence and recovery or peaceful death, so the health and nursing practices must be systematized, planned and based on knowledge and experience. Health and nursing care of patients at risk of developing acute and chronic wounds or already suffering from some form of this imply preventive measures that are provided through patient education, motivation, monitoring, early recognition of risk factors and causes, and reducing or removing them through the prescribed necessary medical treatment which is safe depending on the patient health status. Except for preventive measures, nursing care of patients who already suffer from some form of acute or chronic wounds is focused on the care and treatment of damaged tissue by providing appropriate and timely diagnosis, timely and proper evaluation of the wound and patient general status, knowledge and understanding of the wide range of local, oral and parenteral therapy and treatment, aiming to increase patient safety by preventing progression of the patient general condition and local wound status and reducing the possibility of developing infection or other complications of the underlying disease. In the overall patient management, through nursing process, medical interventions are implemented and aimed to maintain and optimize health status, prevent complications of existing diseases and
4. Active learning - a condition for continuous improvement of Macedonian institutions
Mitreva, Elizabeta; Prodanovska, Vesna
2010-01-01
Each institution ought to give a maximal effort for its own self-maintenance and constant improvement. This continuous improvement comes when the organizational performances are maximizing, managing and broadening the competences within the organization with a new attitude which is based on the continuous learning, innovation and improvement. New management system of the TQM (Total Quality Management) strategy demands lot less finance and timing, and might have same or even stronger effec...
5. Microalloying Boron Carbide with Silicon to Achieve Dramatically Improved Ductility.
An, Qi; Goddard, William A
2014-12-01
Boron carbide (B4C) is a hard material whose value for extended engineering applications such as body armor; is limited by its brittleness under impact. To improve the ductility while retaining hardness, we used density functional theory to examine modifying B4C ductility through microalloying. We found that replacing the CBC chain in B4C with Si-Si, denoted as (B11Cp)-Si2, dramatically improves the ductility, allowing a continuous shear to a large strain of 0.802 (about twice of B4C failure strain) without brittle failure. Moreover, (B11C)-Si2 retains low density and high hardness. This ductility improvement arises because the Si-Si linkages enable the icosahedra accommodate additional shear by rotating instead of breaking bonds. PMID:26278950
6. Behaviour and school achievement in patients with early and continuously treated phenylketonuria
Stemerdink, B.A.; Kalverboer, A.F.; Meere, J.J. van der; Molen, M.W. van der; Huisman, J.; Jong, L.W.A. de; Slijper, F.M.E.; Verkerk, P.H.; Spronsen, F.J. van
2000-01-01
Thirty patients with early and continuously treated phenylketonuria (PKU) between 8 and 20 years of age were compared with 30 controls, matched individually for age, sex, and educational level of both parents, on behaviour rating scales for parents and teachers as well as a school achievement scale.
7. A model for continuous improvement at a South African minerals benefication plant
Ras, Eugene Ras; Visser, Jacobus Krige
2015-01-01
South Africa has a variety of mineral resources, and several minerals beneficiation plants are currently in operation. These plants must be operated effectively to ensure that the end-users of its products remain internationally competitive. To achieve this objective, plants need a sustainable continuous improvement programme. Several frameworks for continuous improvement are used, with variable success rates, in beneficiation plants around the world. However, none of these models specificall...
8. Modelling the Role of Human Resource Management in Continuous Improvement
Jørgensen, Frances; Hyland, Paul; Kofoed, Lise B.
2006-01-01
Although it is widely acknowledged that both Human Resource Management (HRM) and Continuous Improvement have the potential to positively influencing organizational performance, very little attention has been given to how certain HRM practices may support CI, and consequently, a company...
9. The soul of the machine: continual improvement in ISO 14001.
Brouwer, M.A.C.; Koppen, van C.S.A.
2008-01-01
Continual improvement is a key component of ISO 14001, but in contrast to most other specifications in the standard, it is difficult to assess. Based on interviews with 19 certified companies in the chemical, food, and environmental services sectors, this article explores the dynamics of continual i
10. The soul of the machine: continual improvement in ISO 14001
Brouwer, M.A.C.; van Koppen, C.S.A.
2008-01-01
Continual improvement is a key component of ISO 14001, but in contrast to most other specifications in the standard, it is difficult to assess. Based on interviews with 19 certified companies in the chemical, food, and environmental services sectors, this article explores the dynamics of continual i
11. 护理科研成果在促进外科护理教学质量持续改进中的应用%Application of nursing scientific research achievements in promoting the continuous improvement of the quality of surgical nursing teaching
吴赛芬; 芦雅琳; 邓洁英; 赵翠兰; 陈睿
2013-01-01
Objective: To investigate the method and effect of application of nursing scientific research achievements in promoting the continuous improvement of the quality of surgical nursing teaching. Methods: 107 nursing students who had clinical practice in the surgical department of our hospital were divided into the control group( n = 53 ) and the observation group( n = 54 ). The traditional teaching method was used in the control group; the supervision and implementation teams for surgical nursing teaching were set up in the 7 wards of surgical department in the observation group. The scientific research achievement of " Research on the practice of clinical path in nursing teaching in the department of neurosurgery" ( nursing scientific research project of Jiangmen Municipal Health Bureau in 2009 ) was recommended to be implemented. Results:The total mark of the students,the students'satisfaction with teachers and operation frequency was significantly superior in the observation group to the control group after the implementation of clinical path in nursing teaching( P 的研究成果.结果:观察组实施路径教学后在成绩总评、对带教老师满意度、操作频次等方面均明显优于对照组(P＜0.05).结论:应用护理科研成果能促进外科护理教学质量的持续改进,并且护理科研成果需要在临床实践中积极推广和不断完善,以体现科研成果的真正价值.
12. Teacher Tweets Improve Achievement for Eighth Grade Science Students
Carol Van Vooren
2013-02-01
13. Using Online Student Polling for Continuous Improvement Planning
Wingate, Julius Jason
2010-01-01
This study examines the use of Internet polling at schools to gain student input for the improvement of learning conditions to assist in the continuous improvement planning. The study consists of 2006 respondents and three different schools containing the middle school child. The grades included in the study were 5, 6, 7, and 8. Although two…
14. Continuous Improvement in Schools and Districts: Policy Considerations
Best, Jane; Dunlap, Allison
2014-01-01
Discussions about improving public education often focus on outcomes without considering how schools and districts can accomplish those outcomes. Research shows that using a continuous improvement process has proven successful in healthcare, manufacturing, and technology, and may hold potential for use in education as well. This brief defines and…
15. Creating a Cycle of Continuous Improvement through Instructional Rounds
Meyer-Looze, Catherine L.
2015-01-01
Instructional Rounds is a continuous improvement strategy that focuses on the technical core of educational systems as well as educators collaborating side-by-side. Concentrating on collective learning, this process only makes sense within an overall strategy of improvement. This case study examined the Instructional Rounds process in a northern…
16. Closing the Loop on a Continuous Program Improvement Process
Booth, Vickie; Booth, Larry
2010-01-01
The WebBSIT, a Bachelor of Science in Information Technology, is a fully online degree offered through a consortium of five University System of Georgia institutions. This paper begins by summarizing the change management system developed for continuous program improvement. Analysis of data should drive improvement, closing the loop. The balance…
17. Continuous Improvement in Nursing Education through Total Quality Management (TQM
Tang Wai Mun
2013-11-01
Full Text Available Total Quality Management (TQM has generally been validated as a crucial revolution in the management field. Many academicians believe that the concept of TQM is applicable to academics and provides guiding principles towards improving education. Therefore, an increasing number of educational institutions such as schools, colleges and universities have started to embrace TQM philosophies to their curricula.Within the context of TQM, this paper would explore the concept of continuous improvement by using the Deming philosophy. Subsequently, this paper would elaborate on the application of TQM to bring about continuous improvement in the current education system.
18. Improving building energy system performance by continuous commissioning
Liu, M. [Univ. of Nebraska, Omaha, NE (United States)
1999-10-01
Commissioning has played an important role in improved building comfort and reduced energy consumption. This article presents an advanced form of commissioning for existing buildings, called continuous commissioning (CC), which has produced energy savings comparable to those produced by the traditional audit/retrofit process at a third of the cost. It has also increased operating staff skills, reduced maintenance costs, and improved building comfort--extras which are not provided by usual retrofit programs. This article will present the philosophy, process, cost, and savings. Continuous commissioning is a process developed by the Energy Systems Laboratory (ESL) to: (1) optimize the operation of existing systems to improve building comfort and reduce building energy cost; (2) solve existing comfort and IAQ problems; (3) guarantee continuous optimal operation by operational staff in future years; and (4) provide optimal energy retrofit suggestions to owners to minimize the project costs.
19. Continuous monitoring can improve single-photon probability
Raghunathan, Shesha; Brun, Todd
2010-01-01
An engineering technique using continuous quantum measurement together with a change detection algorithm is proposed to improve the probability of single photon emission for a quantum-dot based single-photon source. The technique involves continuous monitoring of the emitter, integrating the measured signal, and a simple change detection circuit to decide when to stop pumping. The idea is to pump just long enough such that the emitter $+$ cavity system is in a state that can emit at most one ...
20. Implementing continuous quality improvement at the facility level.
VanValkenburgh, D A
2001-04-01
Continuous Quality Improvement (CQI) is a disciplined approach to problem solving. The 4 basic building blocks of the program include; leadership, planning, quality control, and quality improvement. It is customer focused, data driven, and empowers the employees to meet the needs of their patients. Management teams that successfully adopt the underlying philosophic tenets of the program and provide adequate resources for training and implementation may realize such benefits as improved clinical outcomes, increased patient and staff satisfaction, increased staff productivity, fewer adverse events, enhanced cost effectiveness, and an improvement in overall organizational performance. PMID:11349250
1. Using continuous process improvement methodology to standardize nursing handoff communication.
Klee, Kristi; Latta, Linda; Davis-Kirsch, Sallie; Pecchia, Maria
2012-04-01
The purpose of this article was to describe the use of continuous performance improvement (CPI) methodology to standardize nurse shift-to-shift handoff communication. The goals of the process were to standardize the content and process of shift handoff, improve patient safety, increase patient and family involvement in the handoff process, and decrease end-of-shift overtime. This article will describe process changes made over a 4-year period as result of application of the plan-do-check-act procedure, which is an integral part of the CPI methodology, and discuss further work needed to continue to refine this critical nursing care process. PMID:21964442
2. Agile kaizen managing continuous improvement far beyond retrospectives
Medinilla, Ángel
2014-01-01
Agile teams have been struggling with the concept of continuous improvement since the first Agile frameworks were developed, and still very little has been written about the practice of continuous improvement in Agile environments. Although team retrospectives have been prescribed and some practices have been introduced in order to implement and facilitate them, the truth is that most Agile teams are conducting dull retrospectives that end with a list of things that have been done wrong, just to repeat the same list two weeks later at the next meeting.Instead of listing hundreds of Japanese-la
3. Design of launch systems using continuous improvement process
Brown, Richard W.
1995-01-01
The purpose of this paper is to identify a systematic process for improving ground operations for future launch systems. This approach is based on the Total Quality Management (TQM) continuous improvement process. While the continuous improvement process is normally identified with making incremental changes to an existing system, it can be used on new systems if they use past experience as a knowledge base. In the case of the Reusable Launch Vehicle (RLV), the Space Shuttle operations provide many lessons. The TQM methodology used for this paper will be borrowed from the United States Air Force 'Quality Air Force' Program. There is a general overview of the continuous improvement process, with concentration on the formulation phase. During this phase critical analyses are conducted to determine the strategy and goals for the remaining development process. These analyses include analyzing the mission from the customers point of view, developing an operations concept for the future, assessing current capabilities and determining the gap to be closed between current capabilities and future needs and requirements. A brief analyses of the RLV, relative to the Space Shuttle, will be used to illustrate the concept. Using the continuous improvement design concept has many advantages. These include a customer oriented process which will develop a more marketable product and a better integration of operations and systems during the design phase. But, the use of TQM techniques will require changes, including more discipline in the design process and more emphasis on data gathering for operational systems. The benefits will far outweigh the additional effort.
4. Building environmental assessment schemes: pragmatism to achieve meaningful improvements
Burnett, J; Ling, L. W. [Hong Kong Polytechnic Univ., Hong Kong Special Administrative Region (China)
1998-11-01
The objective of the Hong Kong Building Environmental Assessment Method (HK-BEAM) is to minimize the adverse effects of new office premises on the global and local environment and to promote healthy indoor environments within reasonable additional costs. It is intended to encourage clients, designers, contractors, operators, and occupants to become more environmentally aware, and to reduce long-term impact that buildings have on the environment. Preliminary assessment of new offices is carried out during the design process, with follow-ups during construction and upon completion before confirming the overall assessment rating. The assessment method is designed to take into account global issues and use of resources. These include energy consumption, office lighting, heat recovery, air conditioning, electricity consumption, ozone depletion, use of timber, storage for recycling of materials, etc. Local issues mentioned are electricity maximum demand, water conservation and waste water discharge, recycled materials, noise from cooling, noise from building services installation, vehicular and pedestrian access, etc. Indoor issues incorporate non-HVAC services, indoor air quality, hazardous materials, lighting design, daylighting, etc. In general, the HK-BEAM scheme has achieved good credibility within Hong Kong. It has improved the awareness of developers as far as environmental issues are concerned, encouraged better design and operational practices. Nevertheless, to date it has had no significant impact on the building stock overall. 8 refs., 2 tabs.
5. Lean management systems: creating a culture of continuous quality improvement.
Clark, David M; Silvester, Kate; Knowles, Simon
2013-08-01
This is the first in a series of articles describing the application of Lean management systems to Laboratory Medicine. Lean is the term used to describe a principle-based continuous quality improvement (CQI) management system based on the Toyota production system (TPS) that has been evolving for over 70 years. Its origins go back much further and are heavily influenced by the work of W Edwards Deming and the scientific method that forms the basis of most quality management systems. Lean has two fundamental elements--a systematic approach to process improvement by removing waste in order to maximise value for the end-user of the service and a commitment to respect, challenge and develop the people who work within the service to create a culture of continuous improvement. Lean principles have been applied to a growing number of Healthcare systems throughout the world to improve the quality and cost-effectiveness of services for patients and a number of laboratories from all the pathology disciplines have used Lean to shorten turnaround times, improve quality (reduce errors) and improve productivity. Increasingly, models used to plan and implement large scale change in healthcare systems, including the National Health Service (NHS) change model, have evidence-based improvement methodologies (such as Lean CQI) as a core component. Consequently, a working knowledge of improvement methodology will be a core skill for Pathologists involved in leadership and management. PMID:23757036
6. Promoting Continuous Quality Improvement in Online Teaching: The META Model
Dittmar, Eileen; McCracken, Holly
2012-01-01
Experienced e-learning faculty members share strategies for implementing a comprehensive postsecondary faculty development program essential to continuous improvement of instructional skills. The high-impact META Model (centered around Mentoring, Engagement, Technology, and Assessment) promotes information sharing and content creation, and fosters…
7. Jump starting of continuous improvement through self-assessment
Jørgensen, Frances; Boer, Harry; Gertsen, Frank
2004-01-01
The innumerable accounts of successful implementation of kaizen in Japan during more than 40 years has led to the expectation that continuous improvement (CI) might offer companies a means to gain and maintain a competitive advantage in the turbulent 1980s and 1990s. However, the majority of CI...
8. Lifetime Impact Identification for Continuous Improvement of Wind Farm Performance
Petersen, Kristian R.; Ruitenburg, Richard J.; Madsen, Erik Skov;
2015-01-01
To become profitable, the cost of offshore windfarms must be reduced. Optimization of the Operations & Maintenance process offers a great potential for cost reductions, especially for existing windfarm. As Continuous Improvement may deliver these cost reductions, this paper aims at fostering CI i...
9. Building a Culture of Continuous Quality Improvement in an Academic Radiology Department.
Katzman, Gregory L; Paushter, David M
2016-04-01
As we enter a new era of health care in the United States, radiologists must be adequately prepared to prove, and continually improve, our value to our customers. This goal can be achieved in large part by providing high-quality services. Although quality efforts on the national and international levels provide a framework for improving radiologic quality, some of the greatest opportunities for quality improvement can be found at the departmental level, through the implementation of total quality management programs. Establishing such a program requires not only strong leadership and employee engagement, but also a firm understanding of the multiple total quality management tools and continuous quality improvement strategies available. In this article, we discuss key tools and strategies required to build a culture of continuous quality improvement in an academic department, based on our experience. PMID:26896936
10. Applying PPM to ERP Maintenance and Continuous Improvement Initiatives
El-Tal, Nada Maria; Fonnesbæk, Majbrit; Kræmmergaard, Pernille
2006-01-01
gain business benefits from the systems. However the ERP literature on how to do this is limited. The purpose of this article is to explore how Project Portfolio Management (PPM) from the Research and Development (R&D) literature can be applied to an ERP second wave context, when companies are to...... prioritize and select maintenance and continuous improvement initiatives. This is done by reviewing the existing literature in the fields of PPM from R&D literature and then by reviewing the existing literature about maintenance and improvement initiatives in the ERP literature, after which the two are...... compared and discussed using three case-studies. The paper contributes with a discussion on how PPM from R&D can be applied to maintenance and continuous improvement initiatives in the second wave of ERP. The paper ends with arguing that emphasis needs to be given to this field, since a conscious and...
11. IMHEX fuel cell repeat component manufacturing continuous improvement accomplishments
Jakaitis, L.A.; Petraglia, V.J.; Bryson, E.S. [M-C Power Corp., Burr Ridge, IL (United States)] [and others
1996-12-31
M-C Power is taking a power generation technology that has been proven in the laboratory and is making it a commercially competitive product. There are many areas in which this technology required scale up and refinement to reach the market entry goals for the IMHEX{reg_sign} molten carbonate fuel cell power plant. One of the primary areas that needed to be addressed was the manufacturing of the fuel cell stack. Up to this point, the fuel cell stack and associated components were virtually hand made for each system to be tested. M-C Power has now continuously manufactured the repeat components for three 250 kW stacks. M-C Powers manufacturing strategy integrated both evolutionary and revolutionary improvements into its comprehensive commercialization effort. M-C Powers objectives were to analyze and continuously improve stack component manufacturing and assembly techniques consistent with established specifications and commercial scale production requirements. Evolutionary improvements are those which naturally occur as the production rates are increased and experience is gained. Examples of evolutionary (learning curve) improvements included reducing scrap rates and decreasing raw material costs by buying in large quantities. Revolutionary improvements result in significant design and process changes to meet cost and performance requirements of the market entry system. Revolutionary changes often involve identifying new methods and developing designs to accommodate the new process. Based upon our accomplishments, M-C Power was able to reduce the cost of continuously manufactured fuel cell repeat components from the first to third 250 kW stack by 63%. This paper documents the continuous improvement accomplishments realized by M-C Power during IMHEX{reg_sign} fuel cell repeat component manufacturing.
12. Continuous Improvement in Education. Advancing Teaching--Improving Learning. White Paper
Park, Sandra; Hironaka, Stephanie; Carver, Penny; Nordstrum, Lee
2013-01-01
In recent years, "continuous improvement" has become a popular catchphrase in the field of education. However, while continuous improvement has become commonplace and well-documented in other industries, such as healthcare and manufacturing, little is known about how this work has manifested itself in education. This white paper attempts…
13. How to Sustain Change and Support Continuous Quality Improvement.
Silver, Samuel A; McQuillan, Rory; Harel, Ziv; Weizman, Adam V; Thomas, Alison; Nesrallah, Gihad; Bell, Chaim M; Chan, Christopher T; Chertow, Glenn M
2016-05-01
To achieve sustainable change, quality improvement initiatives must become the new way of working rather than something added on to routine clinical care. However, most organizational change is not maintained. In this next article in this Moving Points in Nephrology feature on quality improvement, we provide health care professionals with strategies to sustain and support quality improvement. Threats to sustainability may be identified both at the beginning of a project and when it is ready for implementation. The National Health Service Sustainability Model is reviewed as one example to help identify issues that affect long-term success of quality improvement projects. Tools to help sustain improvement include process control boards, performance boards, standard work, and improvement huddles. Process control and performance boards are methods to communicate improvement results to staff and leadership. Standard work is a written or visual outline of current best practices for a task and provides a framework to ensure that changes that have improved patient care are consistently and reliably applied to every patient encounter. Improvement huddles are short, regular meetings among staff to anticipate problems, review performance, and support a culture of improvement. Many of these tools rely on principles of visual management, which are systems transparent and simple so that every staff member can rapidly distinguish normal from abnormal working conditions. Even when quality improvement methods are properly applied, the success of a project still depends on contextual factors. Context refers to aspects of the local setting in which the project operates. Context affects resources, leadership support, data infrastructure, team motivation, and team performance. For these reasons, the same project may thrive in a supportive context and fail in a different context. To demonstrate the practical applications of these quality improvement principles, these principles are
14. Continuous improvement program in ENUSA: personnel participation and six sigma
Since the beginning of its activities ENUSA has been a company committed with the quality of its products and services. To talk about quality is something inherent in ENUSA's daily work ENUSA's position in the market depends on its capacity to satisfy customers expectations with the best products and services, as a result of an efficient management of its processes. The word quality in its broadest sense, means that any activity can be improved. ENUSA has implemented a continuous improvement program as part of its company change project. That program consists of six basic steps: 1.- Managers commitment. 2.- Organization for continuous improvement. 3.- Quality goals. 4.- Training and informing. 5.- Personnel participation. 6.- Methodology. ENUSA has introduced these six steps during 1997-98 period. It is important to point out the commitment degree at all the company levels, focusing the organization to the continuous improvement in a multifunctional way, following the business processes: - Board of Directors - Quality Steering Committee - Quality Improvement Groups (GMC) - Quality Operative Groups (GOC) - Suggestions Mailboxes The following GMC's have been set up and are operative. - Manufacturing GMC - Supplies GMC - Installation GMC - Design GMC - Quality System GM - Projects GMC - Administrative GMC These GMC's have established thirty-six Quality Operative Groups which carry out the improvement projects. The methodology chosen by ENUSA is known as ''SIX SIGMA''. Six sigma programs have proved their huge power in big companies as MOTOROLA and, recently, GE being recognized in all the quality fields. It is, by itself, a change program in which a quality improvement methods is structured with an excellent view of processes, products and services. (Author)
15. Successful integration of ergonomics into continuous improvement initiatives.
Monroe, Kimberly; Fick, Faye; Joshi, Madina
2012-01-01
Process improvement initiatives are receiving renewed attention by large corporations as they attempt to reduce manufacturing costs and stay competitive in the global marketplace. These initiatives include 5S, Six Sigma, and Lean. These programs often take up a large amount of available time and budget resources. More often than not, existing ergonomics processes are considered separate initiatives by upper management and struggle to gain a seat at the table. To effectively maintain their programs, ergonomics program managers need to overcome those obstacles and demonstrate how ergonomics initiatives are a natural fit with continuous improvement philosophies. PMID:22316947
Ronald Anthony Styron; Eddie J Peasant
2010-01-01
This study focused on student achievement in ninth grade schools or academies compared to ninth grade students enrolled in traditional high schools. Student achievement was measured by standardized test scores. Other variables tested were gender and ethnicity. All students used in this study were enrolled in the ninth grade during the 2005-2006 school year at one of six schools selected for this research. Participants were enrolled in Algebra I and/or Biology I course(s) and therefore took th...
17. Community-University Partnerships: Achieving continuity in the face of change
Linda Silka
2008-09-01
Full Text Available A challenge that community-university partnerships everywhere will face is how to maintain continuity in the face of change. The problems besetting communities continually shift and the goals of the university partners often fluctuate. This article describes a decade-long strategy one university has successfully used to address this problem. Over the past ten years, a community-university partnership at the University of Massachusetts Lowell has used summer content funding to respond creativity to shifting priorities. Each summer a research-action project is developed that targets a different content issue that has emerged with unexpected urgency. Teams of graduate students and high school students are charged with investigating this issue under the auspices of the partnership. These highly varied topics have included immigrant businesses, youth asset mapping, women owned businesses, the housing crisis, social program cutbacks, sustainability, and economic development and the arts. Despite their obvious differences, these topics share underlying features that further partnership commitment and continuity. Each has an urgency: the information is needed quickly, often because some immediate policy change is under consideration. Each topic has the advantage of drawing on multiple domains: the topics are inherently interdisciplinary and because they do not “belong” to any single field, they lend themselves to disciplines pooling their efforts to achieve greater understanding. Each also has high visibility: their salience has meant that people were often willing to devote scarce resources to the issues and also that media attention could easily be gained to highlight the advantages of students, partners, and the university working together. And the topics themselves are generative: they have the potential to contribute in many different ways to teaching, research, and outreach. This paper ends with a broader consideration of how partnerships can
18. Paths to continuous improvement of a CRM strategy
Lluís G. Renart
2008-07-01
Full Text Available The concept of relationship marketing has led to a paradigm change in marketing. Over the last few decades, numerous studies have analyzed the impact of customer relationship management (CRM programs on customer satisfaction and loyalty. Quite a few CRM programs have been found to have little or no impact. Having already published several articles and cases on the subject, in this paper we set out to answer the following question: assuming a company already has a reasonably successful CRM strategy in place, how can it continuously adapt and improve that strategy? Our recommendation is that such companies implement a continuous improvement process at four different but complementary levels: first, review and reinforce the company’s mission, culture and values; second, reconsider and, if necessary, redesign the CRM strategy; third, manage the various relationship-building activities more effectively; and lastly, review and, if necessary, improve the quality of material and human resources, program execution and process governance. A systematic review of these four levels or “paths” of improvement should help generate and maintain high quality relationships over time.
19. Improving Our Odds: Success through Continuous Risk Management
Greenhalgh, Phillip O.
2009-01-01
Launching a rocket, running a business, driving to work and even day-to-day living all involve some degree of risk. Risk is ever present yet not always recognized, adequately assessed and appropriately mitigated. Identification, assessment and mitigation of risk are elements of the risk management component of the "continuous improvement" way of life that has become a hallmark of successful and progressive enterprises. While the application of risk management techniques to provide continuous improvement may be detailed and extensive, the philosophy, ideals and tools can be beneficially applied to all situations. Experiences with the use of risk identification, assessment and mitigation techniques for complex systems and processes are described. System safety efforts and tools used to examine potential risks of the Ares I First Stage of NASA s new Constellation Crew Launch Vehicle (CLV) presently being designed are noted as examples. Recommendations from lessons learned are provided for the application of risk management during the development of new systems as well as for the improvement of existing systems. Lessons learned and suggestions given are also examined for applicability to simple systems, uncomplicated processes and routine personal daily tasks. This paper informs the reader of varied uses of risk management efforts and techniques to identify, assess and mitigate risk for improvement of products, success of business, protection of people and enhancement of personal life.
20. Continuous improvement of the BNFL transport integrated management system
The integrated Management System of BNFL Transport and Pacific Nuclear Transport Limited (PNTL) is subject to continuous improvement by the application of established improvement techniques adopted by BNFL. The technique currently being used is the application of a Total Quality Management (TQM) philosophy, involving the identification of key processes, benchmarking against existing measures, initiating various improvement projects and applying process changes within the Company. The measurement technique being used is based upon the European Foundation for Quality Management Model (EFQM). A major initiative was started in 1996 to include the requirements of the Environmental Management Systems standard ISO 14001 within the existing integrated management system. This resulted in additional activities added to the system, modification to some existing activities and additional training for personnel. The system was audited by a third party certification organisation, Lloyds Register Quality Assurance (LRQA), during 1997. This paper describes the arrangements to review and update the integrated management system of BNFL Transport and PNTL to include the requirements of the environmental standard ISO 14001 and it also discusses the continuous improvement process adopted by BNFL Transport. (authors)
1. Improving Secondary School Students' Achievement using Intrinsic Motivation
Albrecht, Erik; Haapanen, Rebecca; Hall, Erin; Mantonya, Michelle
2009-01-01
This report describes a program for increasing students' intrinsic motivation in an effort to increase academic achievement. The targeted population consisted of secondary level students in a middle to upper-middle class suburban area. The students of the targeted secondary level classes appeared to be disengaged from learning due to a lack of…
2. R and D techniques and how to continuously improve them?
Although decommissioning of nuclear installations has been carried out successfully in different countries, and decommissioning is sometimes considered as a mature industrial activity, Research and Development can still improve the operations, and is also needed to keep the current know how. The research and development can bring reduction of costs, limitation of radioactive waste generation, and improve the safety and radioprotection aspects. When one consider that less than 100 facilities are currently in decommissioning for more than 800 reactors (power plants and research reactors, almost half and half) worldwide, the present used technology can be considered as the prehistory of D and D. The paper will focus on the needs for improvements and developments, on the attached constraints and restriction, and will then look at the potential ways to continue R and D and technology improvement. Regarding the rather recent development of the D and D technology and the large remaining market for D and D of nuclear installations, there is still a large field of open development for techniques and technologies for the dismantling of nuclear installations worldwide. Although D and D of all kinds of nuclear installations have proven to be feasible, improvements are surely needed to reduce the costs and waste of D and D, therefore reducing the burden to the plant owners, and to improve the radioprotection of the operations. The same applies for the improvement of the overall operators safety during such operations. There are different ways to go in this direction and the groups to gather the necessary experience and technological data are existing, but the will has to be present to go forward, in a competitive environment. It is difficult to believe that such improvements in the technologies and the approach of decommissioning can rely only on commercial and private initiatives. Therefore, organized international R and D should be promoted wherever it is possible, enhancing
3. A SELF PROCESS IMPROVEMENT FOR ACHIEVING HIGH SOFTWARE QUALITY
DR. SHASHANK.D.JOSHI
2011-05-01
Full Text Available Quality has been one of the most important factors in judging any product. Quality means “a degree or grade of excellence or worth”. Quality is a term that is usually described using adjectives. Quality has several attributes to it, some of which can be quantified using metrics. These attributes such as usability, portability, security, performance, reliability etc have different importance in different projects. Different software quality assurance methods & practices have been used in different software projects to attain the true value. Quality is an attribute which is a distinct feature and it differs with people’s perception. Achieving high software quality involves measurement of software metrics and optimization based on estimated values. As the software systems grow larger, complexity ofdesign and implementation increases, and this in turn is more prone to defects and hence directly affect the quality of the systems. However, in any software project, high quality is always desirable, and many projects have specific quality requirements. Achieving high software quality involves measurement of software metrics and optimization based on estimated values. Developing high quality software is governed by factors such as people, process, technology and cost. This paper attempts to present a novel approach towards achieving high software quality in various kinds of projects under given constraints.
4. Teacher Tweets Improve Achievement for Eighth Grade Science Students
Carol Van Vooren; Corey Bess
2013-01-01
In the Digital Age teachers have fallen far behind the technical skills of their "digital native" students. The implementation of technology as a tool for classroom communication is foreign for most teachers, but highly preferred by students. While teenagers are using Facebook, Twitter, and other social networks to communicate, teachers continue to respond through face-to-face conversations, telephone calls, and email messaging. Twitter, a platform for short message service text, is an online...
5. Quality-control analytical methods: continuous quality improvement.
Venti, Eden M
2006-01-01
It is vital that all compounding pharmacies have a continuous quality improvement program in place by way of standard operating procedures to assure that patients receive high-quality preparations. The program should take into consideration any federal and state regulatory requirements, as well as professional association expectations. Quality control measurements and regular review of those measurements are the foundations of a good quality plan. All pharmacy personnel should be aware of the importance of reporting potential internal quality concerns or problems and should be encouraged to do so without fear of repercussions. Ideally, an error-free compounding pracitice would be the goal. Since this is not practical, quality issues should not be viewed as problems, but as opportunities to improve compounding practices by correcting, before they become pervasive, the processes used in the preparation of prescriptions. PMID:23974418
6. Continued Development and Improvement of Pneumatic Heavy Vehicles
Robert J. Englar
2005-07-15
The objective of this applied research effort led by Georgia Tech Research Institute is the application of pneumatic aerodynamic technology previously developed and patented by us to the design of an appropriate Heavy Vehicle (HV) tractor-trailer configuration, and experimental confirmation of this pneumatic configuration's improved aerodynamic characteristics. In Phases I to IV of our previous DOE program (Reference 1), GTRI has developed, patented, wind-tunnel tested and road-tested blown aerodynamic devices for Pneumatic Heavy Vehicles (PHVs) and Pneumatic Sports Utility Vehicles (PSUVs). To further advance these pneumatic technologies towards HV and SUV applications, additional Phase V tasks were included in the first year of a continuing DOE program (Reference 2). Based on the results of the Phase IV full-scale test programs, these Phase V tasks extended the application of pneumatic aerodynamics to include: further economy and performance improvements; increased aerodynamic stability and control; and safety of operation of Pneumatic HVs. Continued development of a Pneumatic SUV was also conducted during the Phase V program. Phase V was completed in July, 2003; its positive results towards development and confirmation of this pneumatic technology are reported in References 3 and 4. The current Phase VI of this program was incrementally funded by DOE in order to continue this technology development towards a second fuel economy test on the Pneumatic Heavy Vehicle. The objectives of this current Phase VI research and development effort (Ref. 5) fall into two categories: (1) develop improved pneumatic aerodynamic technology and configurations on smaller-scale models of the advanced Pneumatic Heavy Vehicle (PHV); and based on these findings, (2) redesign, modify, and re-test the modified full-scale PHV test vehicle. This second objective includes conduct of an on-road preliminary road test of this configuration to prepare it for a second series of SAE Type
7. Student Achievement Goal Setting: Using Data to Improve Teaching and Learning
Stronge, James H.; Grant, Leslie W.
2009-01-01
The first book in the James H. Stronge Research-to-Practice series focuses on improving student achievement through academic goal setting. It offers the tools and plan of action to use performance data to improve instructional practice and increase student achievement. The book is divided into three parts: (1) How Student Achievement Data Can Be…
8. Steam generator replacement: a story of continuous improvement
This paper provides a review of the history of steam generator replacement in the US focusing on the last five years. From the early replacements in the 1980s, there have been major technology improvements resulting in dramatically shorter outages and reduced radiological exposure for workers. Even though the changes for the last five years have been less dramatic, the improvement trend continues. No two steam generator replacement (SGR) projects are the same and there are some major differences including; the access path for the components to containment (is a construction opening in containment required), type of containment, number of steam generators, one piece or two piece replacement, plant type (Westinghouse, CE or B and W) and plant layout. These differences along with other variables such as delays due to plant operations and other activities not related to the steam generator replacement make analysis of performance data difficult. However, trends in outage performance and owner expectations can be identified. How far this trend will go is also discussed. Along with the trend of improved performance, there is also a significant variation in performance. Some of the contributors to this variation are identified. This paper addresses what is required for a successful outage, meeting the increasing expectations and setting new records. The authors will discuss various factors that contribute to the success of a steam generator replacement. These factors include technical issues and, equally important, organizational interface and the role the customer plays. Recommendations are provided for planning a successful steam generator replacement outage. (author)
9. Modification of provider behavior to achieve improved asthma outcomes.
Jones, Erika M; Portnoy, Jay M
2003-11-01
Despite an abundance of scientific evidence supporting the use of guidelines, adherence to asthma practice guidelines by physicians generally is low, regardless of provider and patient characteristics. As a result, scientific information, obtained with great effort and at huge expense, is not being translated into clinical practice. To remedy this, we developed a disease management program that emphasizes alteration of provider behavior using operant conditioning. We did this by placing asthma educators in private offices for up to 8 weeks. The educators used a combination of problem-based learning, role modeling, and operant conditioning with positive reinforcement to affect behavior change. As a result of these behavior changes, by the end of 8 weeks the cost to treat asthma patients decreased, despite an increase in the cost of medications. We concluded that behavior-oriented programs targeted at provider offices can lead to improved asthma care while reducing costs. PMID:14531969
10. The continuous improvement system of nuclear power plant of Laguna Verde
This paper describes the continuous improvement system of nuclear power plant of Laguna Verde and the achievements in implementing the same and additionally two study cases are presents. In February 2009 is noteworthy because the World Association of Nuclear Operators we identified as a learning organization, qualification which shows that the continuous improvement system has matured, and this system will expose as I get to learn to capitalize on our own experiences and external experiences diffused by the nuclear industry. In 2007 the management of nuclear power plants integrates its improvement systems and calls it continuous improvement system and is presented in the same extensive report that won the National Quality Award. This system is made up of 5 subsystems operating individually and are also related 1) human performance; 2) referential comparison or benchmarking; 3) self-assessment; 4) corrective action and 5) external operating experience. Five subsystems that plan, generate, capture, manage, communicate and protect the knowledge generated during the processes execution of nuclear power plant of Laguna Verde, as well as from external sources. The target set in 2007 was to increase the intellectual capital to always give response to meeting the security requirements, but creating a higher value to quality, customer, environment protection and society. In brief each of them, highlighting the objective, expectations management, implementation and some benefits. At the end they will describe two study cases selected to illustrate these cases as the organization learns by their continuous improvement system. (Author)
11. Initiatives for the improvement of continuous management training
Jon Landeta
2015-03-01
Full Text Available Purpose. This work aims to present, from the company viewpoint, a structured account of management proposals and practices directed toward improving the intensity and effectiveness of continuous management training (CMT. Design/methodology/approach. The article takes as its main theoretical referents the Theory of Human Capital, the Resource-Based Vision and the contributions made via the new institutional economy with regard to the problems of information asymmetry between companies, employees and training providers and completes the proposals that derive from this theoretical approach. To do this, experience-based contributions are collected from a selection of company training and HR managers from twelve Basque companies characterised by their strong investment in management training. The methodology used was qualitative and obtained by different qualitative techniques: Focus Groups, Nominal Groups and the Delphi Method, which make up the so-called Hybrid Delphi. Findings and implications. The proposals are aimed at the main agents in training activity: training providers, associations and public agents engaged in management training and, particularly, companies themselves. The initiatives seek above all to increase training market transparency, to improve mutual commitments between companies and managers, and to link training and development with culture and strategic management, so that firms make optimal investment in management training. Originality/value. The methodology used is original, and the contributions are consistent with the theory, have a proven practical utility, and are presented in a hierarchy, which facilitates decision making.
12. Implementing a customer focused continual business improvement program to improve the maintenance process
Global market pressures and increasing competition demands that successful companies establish a continual business improvement program as part of implementing its business strategy. Such programs must be driven by the definition of quality from the customer's perspective. This customer quality focus often requires a change in all aspects of the business including products, services, processes and culture. This paper will describe how Atomic Energy of Canada Limited implemented a Continual Business Improvement Program in their Nuclear Laboratories Business Unit. In particular, to review how the techniques were applied to improve the maintenance process and the status of the project. Customer (internal users of the processes at CRL) feedback has shown repeatedly there is dissatisfaction of the maintenance process. Customers complain about jobs not getting done to schedule or being deferred. A project has been launched with the following goals: to improve the maintenance process customer satisfaction and increase trades wrench time by 30 minutes / trade / day. DMAIC (Define-Measure-Analyze-Improve-Control) methodology was applied to find out the Root Cause(s) of the problem, provide solutions, and implement improvements. The expected Operational Benefits include: Executing work efficiently to quality standards and business performance of the site, improve maintenance efficiencies, reduce cycle time for maintenance process and improve process yield, and improve customer and employee satisfaction. (author)
13. Improving continuing medical education by enhancing interactivity: lessons from Iran
FAGHIHI, SEYED ALIAKBAR; KHANKEH, HAMID REZA; HOSSEINI, SEYED JALIL; SOLTANI ARABSHAHI, SEYED KAMRAN; FAGHIH, ZAHRA; PARIKH, SAGAR V.; SHIRAZI, MANDANA
2016-01-01
Introduction Continuing Medical Education (CME) has been considered as a lifelong commitment for doctors to provide the optimal care for patients. Despite a long history of creating CME programs, outcomes are far from ideal. The present qualitative study aims to clarify the barriers affecting effectiveness of the CME programs in Iran based on the experiences of general practitioners. Methods Sixteen general practitioners were recruited to participate in in-depth interviews and field observations concerning experiences with CME. The study was performed using a qualitative content analysis method. The codes, categories and themes were explored through an inductive process in which the researchers moved from specific to general. Results The participants’ experiences identified a number of barriers, particularly insufficient interaction with the instructors; additional problems included the teachers’ use of an undifferentiated approach; unreal and abstract CME; and ignorance of the diverse reasons to participate in CME. Conclusion Based on the study results, there are multiple barriers to effective implementation of CME in Iran. The key barriers include insufficient interaction between the trainees and providers, which must be considered by other stakeholders and program designers. Such interactions would facilitate improved program design, invite more specific tailoring of the education to the participants, allow for more effective educational methods and set the stage for outcome evaluation from the learners actually applying their new knowledge in practice. Replication of these findings with another sample would improve confidence in these recommendations, but these findings are broadly consistent with findings in the educational literature on improving the efficacy of CME. PMID:27104199
14. Improved Continuous-Time Higher Harmonic Control Using Hinfinity Methods
Fan, Frank H.
The helicopter is a versatile aircraft that can take-off and land vertically, hover efficiently, and maneuver in confined space. This versatility is enabled by the main rotor, which also causes undesired harmonic vibration during operation. This unwanted vibration has a negative impact on the practicality of the helicopter and also increases its operational cost. Passive control techniques have been applied to helicopter vibration suppression, but these methods are generally heavy and are not robust to changes in operating conditions. Feedback control offers the advantages of robustness and potentially higher performance over passive control techniques, and amongst the various feedback schemes, Shaw's higher harmonic control algorithm has been shown to be an effective method for attenuating harmonic disturbance in helicopters. In this thesis, the higher harmonic disturbance algorithm is further developed to achieve improved performance. One goal in this thesis is to determine the importance of periodicity in the helicopter rotor dynamics for control synthesis. Based on the analysis of wind tunnel data and simulation results, we conclude the helicopter rotor can be modeled reasonably well as linear and time-invariant for control design purposes. Modeling the helicopter rotor as linear time-invariant allows us to apply linear control theory concepts to the higher harmonic control problem. Another goal in this thesis is to find the limits of performance in harmonic disturbance rejection. To achieve this goal, we first define the metrics to measure the performance of the controller in terms of response speed and robustness to changes in the plant dynamics. The performance metrics are incorporated into an Hinfinity control problem. For a given plant, the resulting Hinfinity controller achieves the maximum performance, thus allowing us to identify the performance limitation in harmonic disturbance rejection. However, the Hinfinity controllers are of high order, and may
15. The Empirical Relationship among Organisational Learning, Continuous Improvement and Performance Improvement
Sun, Hongyi; Ho, Kario; Ni, Wenbin
2008-01-01
There are still many questions remain unanswered about the relationship between Organisational Learning (OL) and Continuous Improvement (CI). For example, how do OL and CI contribute to business performance? Are OL and CI equal? Do OL and CI support each other? Should OL and CI be implemented separately or together? If together, how to integrate…
16. IMPROVEMENT EVALUATION ACHIEVED BY IMPLEMENTING KAIZEN METHODOLOGY IN A MACHINING COMPANY
Fernanda Cristina Pierre
2016-04-01
Full Text Available In order to achieve success, companies should consider the search for increasingly higher standards of productivity and quality. Within this context, this paper aims at observing the integration of Kaizen tool searching for a better operating performance. This integration took place through the application of Lean Manufacturing elements, aimed at streamlining the flow of value through waste reduction, in order to systematize the process of analyzing and controlling process variations to obtain higher quality. This paper based on a case study, observed the changes made for accommodating this approach in an aircraft parts manufacturer. It was studied the adopted structure for its promotion as well as the way in which the improvement projects were developed through it. Results, considering improvement on cycle, delivery performance, improved quality scores and internal, lead time, unnecessary movement reduction and overtime work, indicated that the use of this methodology contributed for the company´s upgrade making it more comprehensive and effective the continuous improvement process.
17. Six Years Into Its Mission, NASA's Chandra X-ray Observatory Continues to Achieve Scientific Firsts
2005-08-01
In August 1999, NASA's Chandra X-ray Observatory opened for business. Six years later, it continues to achieve scientific firsts. "When Chandra opened its sunshade doors for the first time, it opened the possibility of studying the X-ray emission of the universe with unprecedented clarity," said Chandra project scientist Dr. Martin Weisskopf of NASA's Marshall Space Flight Center in Huntsville, Ala. "Already surpassing its goal of a five-year life, Chandra continues to rewrite textbooks with discoveries about our own solar system and images of celestial objects as far as billions of light years away." Based on the observatory's outstanding results, NASA Headquarters in Washington decided in 2001 to extend Chandra s mission from five years to ten. During the observatory s sixth year of operation, auroras from Jupiter, X-rays from Saturn, and the early days of our solar system were the focus of Chandra discoveries close to home -- discoveries with the potential to better understand the dynamics of life on Earth. Jupiter's auroras are the most spectacular and active auroras in the solar system. Extended Chandra observations revealed that Jupiter s auroral X-rays are caused by highly charged particles crashing into the atmosphere above Jupiter's poles. These results gave scientists information needed to compare Jupiter's auroras with those from Earth, and determine if they are triggered by different cosmic and planetary events. Mysterious X-rays from Saturn also received attention, as Chandra completed the first observation of a solar X-ray flare reflected from Saturn's low-latitudes, the region that correlates to Earth's equator and tropics. This observation led scientists to conclude the ringed planet may act as a mirror, reflecting explosive activity from the sun. Solar-storm watchers on Earth might see a surprising benefit. The results imply scientists could use giant planets like Saturn as remote-sensing tools to help monitor X-ray flaring on portions of the sun
18. A formula for continued improvement: Audit follow-up
In his book Management Audits, Allan J. Sayle states, ''QA standards stipulate that corrective action, required as a result of performing an audit, be followed up and closed out. There would, indeed, be little point in performing audits, requiring corrective action, or having a QA system at all if the auditee knows that the auditor will never verify that the corrective action has been efficaciously implemented.'' The QA auditor has an obligation to include follow-up in the overall audit planning. All too often the auditor will go to great lengths to plan and perform an audit only to have a recurring finding in the next audit. The proposed corrective action was only promissory and was not designed to stop the problem from recurring or to identify its root cause. Auditors do a disservice to the overall QA program and particularly to the customer when they fail to follow up and verify that an audit corrective action has been effectively implemented. In this paper, the techniques used by the quality assurance auditors at the Pacific Northwest Laboratory (PNL) will be presented. Although PNL is a research and development laboratory, the techniques outlined in this paper could be applied to any industry conducting quality assurance audits. Most important, they provide a formula for continued improvement by assuring that audit follow-up is timely, meaningful, and permanent
19. 78 FR 69336 - Title I-Improving the Academic Achievement of the Disadvantaged
2013-11-19
... FR 52467) a notice of proposed rulemaking regarding modified academic achievement standards and alternate assessments based on those modified academic achievement standards. This notice established an... CFR Part 200 Title I--Improving the Academic Achievement of the Disadvantaged AGENCY: Office...
20. Continued SOFC cell and stack technology and improved production methods
Wandel, M.; Brodersen, K.; Phair, J. (and others)
2009-05-15
Within this project significant results are obtained on a number of very diverse areas ranging from development of cell production, metallic creep in interconnect to assembling and test of stacks with foot print larger than 500 cm2. Out of 38 milestones 28 have been fulfilled and 10 have been partly fulfilled. This project has focused on three main areas: 1) The continued cell development and optimization of manufacturing processes aiming at production of large foot-print cells, improving cell performance and development environmentally more benign production methods. 2) Stack technology - especially stacks with large foot print and improving the stack design with respect to flow geometry and gas leakages. 3) Development of stack components with emphasis on sealing (for 2G as well as 3G), interconnect (coat, architecture and creep) and test development. Production of cells with a foot print larger than 500 cm2 is very difficult due to the brittleness of the cells and great effort has been put into this topic. Eight cells were successfully produced making it possible to assemble and test a real stack thereby giving valuable results on the prospects of stacks with large foot print. However, the yield rate is very low and a significant development to increase this yield lies ahead. Several lessons were learned on the stack level regarding 'large foot print' stacks. Modelling studies showed that the width of the cell primarily is limited by production and handling of the cell whereas the length (in the flow direction) is limited by e.g. pressure drop and necessary manifolding. The optimal cell size in the flow direction was calculated to be between approx20 cm and < 30 cm. From an economical point of view the production yield is crucial and stacks with large foot print cell area are only feasible if the cell production yield is significantly enhanced. Co-casting has been pursued as a production technique due to the possibilities in large scale production
1. 77 FR 4688 - National School Lunch Program: Direct Certification Continuous Improvement Plans Required by the...
2012-01-31
... Lunch Program: Direct Certification Continuous Improvement Plans Required by the Healthy, Hunger-Free... continuous improvement plans if they fail to do so. This rule also proposes to amend NSLP and SNAP... a continuous improvement plan (CIP) aimed at fully meeting the benchmarks and improving...
2. Achieving Continuity of Care: Facilitators and Barriers in Community Mental Health Teams
Jones Ian Rees
2011-03-01
Full Text Available Abstract Background The integration of mental health and social services for people diagnosed with severe mental illness (SMI has been a key aspect of attempts to reform mental health services in the UK and aims to minimise user and carer distress and confusion arising from service discontinuities. Community mental health teams (CMHTs are a key component of UK policy for integrated service delivery, but implementing this policy has raised considerable organisational challenges. The aim of this study was to identify and explore facilitators and barriers perceived to influence continuity of care by health and social care professionals working in and closely associated with CMHTs. Methods This study employed a survey design utilising in-depth, semi-structured interviews with a proportionate, random sample of 113 health and social care professionals and representatives of voluntary organisations. Participants worked in two NHS Mental Health Trusts in greater London within eight adult CMHTs and their associated acute in-patient wards, six local general practices, and two voluntary organisations. Results Team leadership, decision making, and experiences of teamwork support were facilitators for cross boundary and team continuity; face-to-face communication between teams, managers, general practitioners, and the voluntary sector were facilitators for information continuity. Relational, personal, and longitudinal continuity were facilitated in some local areas by workforce stability. Barriers for cross boundary and team continuity were specific leadership styles and models of decision making, blurred professional role boundaries, generic working, and lack of training for role development. Barriers for relational, personal, and longitudinal continuity were created by inadequate staffing levels, high caseloads, and administrative duties that could limit time spent with users. Incompatibility of information technology systems hindered information
3. Integrated product and process system with continuous improvement in the auto parts industry
I.B. Silva
2009-06-01
Full Text Available Purpose: Quality systems (QS update must be based on the enterprise organization to assure customer satisfaction, as Deming, Juran and Feigenbaum did in their time, to seek improvement processes to reach high quality performance. This way, the proposal of this paper is the development of quality system integration model of product and process with continuous improvement.Design/methodology/approach: To reach this goal, a Brazilian automotive parts quality system was improved through the Computer Integrated Manufacturing (CIM, Design for Manufacturing and Assembly (DFMA and Lean Six Sigma (LSS methodologies.Findings: The paper shows what the problems are during the factory quality system management. The results achieved in the studied company show the performance quality evolution through their indicators.Research limitations/implications: The article presents quality system problems of only one Brazilian plant of an automotive industry.Practical implications: Presented in this article should be a way to look for continuous improvement methods.Originality/value: The paper is supported on the authors’ practical experiences to improve the quality system at a Brazilian plant.
4. X-rays taken by radiologists. Influence on a continuous quality improvement process?
5. Tennessee TCAP Science Scale Scores: Implications for Continuous Improvement and Educational Reform or Is It Possible To Beat the Odds?
Evidence provided by analysis of science scale scores on the McGraw-Hill CTB/4 science test for grades 2 through 8 in Tennessee, part of the Tennessee Comprehensive Assessment Program (TCAP), shows that it is possible for high achieving school systems to show continuous improvement from year to year. These results would tend to offset fears that…
6. Human Governance: A Neglected Mantra for Continuous Performance Improvement
Salleh, Arfah; Ahmad, Aziuddin; Kumar, Naresh
2009-01-01
Every individual should be entrusted with an internal driver to strive their best towards achieving their potential and to manifest their performance through innovative means. This can be reached only under circumstances where the abstract human values and principles are recognized and indoctrinated in the culture. The strategies discussed in this…
7. Teachers' Perception of Their Principal's Leadership Style and the Effects on Student Achievement in Improving and Non-Improving Schools
Hardman, Brenda Kay
2011-01-01
Teachers' perceptions of their school leaders influence student achievement in their schools. The extent of this influence is examined in this study. This quantitative study examined teachers' perceptions of the leadership style of their principals as transformational, transactional or passive-avoidant in improving and non-improving schools in…
8. Improving the Relationship between Continuing Education Leadership and Marketing Directors
Fong, Jim
2009-01-01
In this economy, college and university continuing education units will not automatically reap the benefits of returning adult learners as in past recessions: this economy caused a drastic reduction of resources available to the workforce and for personal revenue. As a result of decreased personal income and workforce training funding, competition…
9. Modular Approach for Continuous Cell-Level Balancing to Improve Performance of Large Battery Packs: Preprint
Muneed ur Rehman, M.; Evzelman, M.; Hathaway, K.; Zane, R.; Plett, G. L.; Smith, K.; Wood, E.; Maksimovic, D.
2014-10-01
Energy storage systems require battery cell balancing circuits to avoid divergence of cell state of charge (SOC). A modular approach based on distributed continuous cell-level control is presented that extends the balancing function to higher level pack performance objectives such as improving power capability and increasing pack lifetime. This is achieved by adding DC-DC converters in parallel with cells and using state estimation and control to autonomously bias individual cell SOC and SOC range, forcing healthier cells to be cycled deeper than weaker cells. The result is a pack with improved degradation characteristics and extended lifetime. The modular architecture and control concepts are developed and hardware results are demonstrated for a 91.2-Wh battery pack consisting of four series Li-ion battery cells and four dual active bridge (DAB) bypass DC-DC converters.
10. Benchmarking--Measuring and Comparing for Continuous Improvement.
Henczel, Sue
2002-01-01
Discussion of benchmarking focuses on the use of internal and external benchmarking by special librarians. Highlights include defining types of benchmarking; historical development; benefits, including efficiency, improved performance, increased competitiveness, and better decision making; problems, including inappropriate adaptation; developing a…
11. Observations of human factors as a continuous improvement tool
Principles for Excellence in Human Performance should promote behaviors throughout an organization that support safety and reliable operation of the plant. Such behaviors must be clearly defined, communicated and reinforced by managers, on a continuous basis. To identify if workers behaviors are in compliance with those expected is paramount to have an observations program in place, which in one hand identifies deviations from expectations to correct them, and on the other promotes the desired behaviors through positive reinforcement. (Author)
12. Search for continuous gravitational waves: Improving robustness versus instrumental artifacts
Keitel, D.; Prix, R.; Papa, M.; Leaci, P.; Siddiqi, M.
2013-01-01
The standard multidetector F-statistic for continuous gravitational waves is susceptible to false alarms from instrumental artifacts, for example monochromatic sinusoidal disturbances ('lines'). This vulnerability to line artifacts arises because the F-statistic compares the signal hypothesis to a Gaussian-noise hypothesis, and hence is triggered by anything that resembles the signal hypothesis more than Gaussian noise. Various ad-hoc veto methods to deal with such line artifacts have been pr...
13. Training Theory of Mind and Executive Control: A Tool for Improving School Achievement?
Kloo, Daniela; Perner, Josef
2008-01-01
In the preschool years, there are marked improvements in theory of mind (ToM) and executive functions. And, children's competence in these two core cognitive domains is associated with their academic achievement. Therefore, training ToM and executive control could be a valuable tool for improving children's success in school. This article reviews…
14. Cyberbullying: Assessment of Student Experience for Continuous Improvement Planning
Strom, Paris S.; Strom, Robert D.; Wingate, Julius J.; Kraska, Marie F.; Beckert, Troy E.
2012-01-01
This study examines the use of polling students to improve conditions of learning in their school. Students from three schools (N = 2,006) in Grades 5, 6, 7, and 8 completed an online poll about how cyberbullying affects their personal lives. Principals' impressions about the benefits of student polling are explained along with the Cyberbullying…
15. Improvement of Fibre Placement Accuracy in Continuous Tow Shearing Process
Kim, Byung Chul; Zympeloudis, Evangelos D
2015-01-01
Automated Fibre Placement (AFP) is the state-of-the-art technology to produce complex composite aircraft parts. However, its main disadvantage is that it generally produces the process-induced defect such as fibre buckling in steering process, which is required to lay up the tow following non-geodesic paths on a complex mould. Continuous Tow Shearing (CTS) was developed to eliminate the fibre buckling by using the in-plane shear deformation of the tow material [1, 2]. The uniquely designed he...
16. AN IMPROVED ANT COLONY ALGORITHM IN CONTINUOUS OPTIMIZATION
Ling CHEN; Jie SHEN; Ling QIN; Hongjian CHEN
2003-01-01
A modified ant colony algorithm for solving optimization problem with continuous parameters is presented. In the method, groups of candidate values of the components are constructed, and each value in the group has its trail information. In each iteration of the ant colony algorithm, the method first chooses initial values of the components using the trail information. Then GA operations of crossover and mutation can determine the values of the components in the solution. Our experimental results on the problem of nonlinear programming show that our method has a much higher convergence speed and stability than those of simulated annealing (SA) and GA.
17. 30% improvement in absorption spectroscopy detectivity achieved by the detuned loading of a quantum cascade laser.
Michel, Florian; Juretzka, Carsten; Carras, Mathieu; Elsäßer, Wolfgang
2014-11-01
We perform a direct absorption spectroscopy experiment of carbon monoxide at 2193 cm(-1) by exploring the detectivity improvement potential of an intensity noise (IN)-reduced distributed feedback (DFB) quantum cascade laser. This was achieved by a detuned loading approach via a short, phase-sensitive optical feedback cavity. Under optimum IN reduction conditions, we obtain an improvement in signal-to-noise ratio from 733 to 1048, which transfers into a detection limit improvement from 1.2 ppm to 840 ppb. Therefore, we achieve a 30% lower detection limit, with the IN reduced when compared to the free-running case. PMID:25361352
18. Improving training tools for continuing operator qualification in Spain
There are currently nine nuclear power plants in service in Spain; the most recent started commercial operation in 1988. Spanish legislation requires operators to have an academic technical background of at least 3 yr. The turnover rate is <5%, and in recent years, symptom-based emergency procedure has been introduced. These facts have given rise to a situation in which Spanish licensed operators are demanding more in-depth training to avoid a stagnant routine and boredom. In responding to this challenge, Tecnatom has had to significantly update its two simulators for boiling water reactor (BWR) and pressurized water reactor (PSR) plants, to ensure coverage of the emergency procedures and has had to create a tool - the Interactive Graphics Simulator - that allows these problems to be ameliorated. With a view to updating its simulators, Tecnatom initiated in 1985 a project known as advanced simulation models (MAS), which was completed at the end of 1990. The TRACS code is a real-time advanced thermohydraulic code for upgrading Tecnatom's nuclear plant simulators. The interactive graphic simulator, (SGI) is a system that provides a graphic display of the models of a full-scope simulator by means of color monitors. The two new tools used are enabling higher levels of motivation to be achieved among the plant operations personnel, especially with respect to requalification
19. Improving teleportation of continuous variables by local operations
We study a continuous-variable (CV) teleportation protocol based on a shared entangled state produced by the quantum-nondemolition (QND) interaction of two vacuum states. The scheme utilizes the QND interaction or an unbalanced beam splitter in the Bell measurement. It is shown that in the nonunity gain regime the signal transfer coefficient can be enhanced while the conditional variance product remains preserved by applying appropriate local squeezing operation on sender's part of the shared entangled state. In the unity gain regime, it is demonstrated that the fidelity of teleportation can be increased with the help of the local squeezing operations on parts of the shared entangled state that effectively convert our scheme to the standard CV teleportation scheme. Further, it is proved analytically that such a choice of the local symplectic operations minimizes the noise by which the mean number of photons in the input state is increased during the teleportation. Finally, our analysis reveals that the local symplectic operation on sender's side can be integrated into the Bell measurement if the interaction constant of the interaction in the Bell measurement can be adjusted properly
20. Positioning Continuing Education: Boundaries and Intersections between the Domains Continuing Education, Knowledge Translation, Patient Safety and Quality Improvement
Kitto, Simon; Bell, Mary; Peller, Jennifer; Sargeant, Joan; Etchells, Edward; Reeves, Scott; Silver, Ivan
2013-01-01
Public and professional concern about health care quality, safety and efficiency is growing. Continuing education, knowledge translation, patient safety and quality improvement have made concerted efforts to address these issues. However, a coordinated and integrated effort across these domains is lacking. This article explores and discusses the…
1. Improving the Syllable-Synchronous Network Search Algorithm for Word Decoding in Continuous Chinese Speech Recognition
郑方; 武健; 宋战江
2000-01-01
The previously proposed syllable-synchronous network search (SSNS) algorithm plays a very important role in the word decoding of the continuous Chinese speech recognition and achieves satisfying performance. Several related key factors that may affect the overall word decoding effect are carefully studied in this paper, including the perfecting of the vocabulary, the big-discount Turing re-estimating of the N-Gram probabilities, and the managing of the searching path buffers. Based on these discussions, corresponding approaches to improving the SSNS algorithm are proposed. Compared with the previous version of SSNS algorithm, the new version decreases the Chinese character error rate (CCER) in the word decoding by 42.1% across a database consisting of a large number of testing sentences (syllable strings).
2. Indicators of the management for the continuous improvement of the radiological safety in a radioactive facility
The use of safety indicators is common in the nuclear industry. In this work the implementation of indicators for the efficiency analysis of the radiological safety management system of a radioactive installation is presented. Through the same ones the occupational exposure, the training Y authorization of the personnel, the control of practices Y radioactive inventory, the results of the radiological surveillance, the occurrence of radiological events, the aptitude of the monitoring equipment, the management of the radioactive waste, the public exposure, the audits Y the costs of safety are evaluated. Its study is included in the periodic training of the workers. Without this interrelation it is not possible to maintain the optimization of the safety neither to achieve a continuous improvement. (Author)
3. Does Children’s Academic Achievement Improve when Single Mothers Marry?
Wagmiller, Robert L.; Gershoff, Elizabeth; Veliz, Philip; Clements, Margaret
2010-01-01
Promoting marriage, especially among low-income single mothers with children, is increasingly viewed as a promising public policy strategy for improving developmental outcomes for disadvantaged children. Previous research suggests, however, that children’s academic achievement either does not improve or declines when single mothers marry. In this paper, we argue that previous research may understate the benefits of mothers’ marriages to children from single-parent families because (1) the sho...
4. Kaizen philosophy a manner of continuous improvement of processes and products
T. Karkoszka
2009-08-01
Full Text Available Purpose: of the paper aimed at motivating the legitimacy of implementation of kaizen system – the philosophy conducting to the continuous improvement of processes and products by the responsibility of all workers.Design/methodology/approach: used for the research has embraced the estimation of kaizen ideas including: connection of the kaizen with the range of duty, employee’s creativeness, practicality and efficiency of the idea, resources, deadlines in operations, involvement in accustoming the idea, possible success of idea, safety, quality, cost and time.Findings: of research are as follows: kaizen idea should have positive influence on areas outside department of employee, surpass the level of ordinary scope of duties of employee, be characterised by high level of practicality, what means that employee has devoted a lot personal time and energy to achieve effective implementation and obtain the results exceeding desired ones; correct functioning of kaizen system should be confirmed by statistics of implementation.Practical implications: can apply in case of any organisation which manages the quality by identification of the improvement area, selection of the key problem, definition of the cause of improvement, planning of the measurement, implementation of the improvement idea, analysis and comparison of the results and standardisation.Originality/value: of the presented paper is being constituted by the procedure of the carried out estimation of kaizen ideas taking into account practicality and efficiency of the idea, direct influence of it on safety, quality, cost and time as well as creativity and personal involvement of employee, which can be used as an improvement tool in every organisation estimating every improving activity.
5. Instructional Leadership Influence on Collective Teacher Efficacy to Improve School Achievement
Fancera, Samuel F.; Bliss, James R.
2011-01-01
The purpose of this study was to examine whether instructional leadership functions, as defined in Hallinger's Principal Instructional Management Rating Scale, positively influence collective teacher efficacy to improve school achievement. Teachers from sample schools provided data for measures of collective teacher efficacy and instructional…
6. Investing in Educator Data Literacy Improves Student Achievement. Evidence of Impact: The Oregon Data Project
Data Quality Campaign, 2012
2012-01-01
Since 2007 the Oregon DATA Project has been investing resources to provide educators on-the-job training around effective data use to improve student achievement. New evidence shows that their efforts are paying off. A 2011 Oregon DATA Project report detailed the impact of their investment in the state's educators, finding the following: (1)…
7. The Big Improvement in PISA 2009 Reading Achievements in Serbia: Improvement of the Quality of Education or Something Else?
Dragica Pavlović Babić
2011-01-01
Full Text Available The PISA 2009 results in Serbia show a big improvement in reading literacy compared to 2006 – the average score is 41 points higher, which is equal to the effect of a whole year of schooling in OECD countries and represents the second highest improvement ever recorded in a PISA study. In the present paper, we discuss potential reasons for such a big improvement based on analysis of the PISA 2009 reading achievements in different countries, with a special focus on countries from the same region (Croatia, Slovenia, Montenegro, Bulgaria, Romania and Albania. The analysis shows that the largest part of the improvement was realised at lower achieving levels, suggesting that the dominant method of teaching in schools is a traditional method oriented towards the acquisition and reproduction of academic knowledge. Findings of data analysis support the conclusion that the improvement is mainly the result of certain contextual factors, such as higher student motivation and a high level of official support for the PISA study in Serbia, rather than representing a real improvement in the quality of education.
8. 78 FR 40625 - National School Lunch Program: Direct Certification Continuous Improvement Plans Required by the...
2013-07-08
... Certification Continuous Improvement Plans Required by the Healthy, Hunger-Free Kids Act of 2010; Approval of... National School Lunch Program: Direct Certification Continuous Improvement Plans Required by the Healthy... February 22, 2013 at 78 FR 12221 was approved by OMB on April 10, 2013, under OMB Control Number...
9. Achieving continuous improvement in reductions in foodborne listeriosis: A risk-based approach
Gram, Lone
2005-01-01
-risk populations. This requires implementation of effective food safety control measures and ensuring that these control strategies are consistently met. Most effective strategies to control L. monocytogenes in high-risk foods include (1) good manufacturing practices, sanitation standard operating procedures......, and hazard analysis critical control point programs to minimize environmental L. monocytogenes contamination and to prevent cross-contamination in processing plants and at retail; (2) an intensive environmental sampling program in plants processing high-risk foods and an effective corrective action plan...
10. Prediction and improvement of the maximum achievable damping with collocated control
Holterman, Jan; Vries, de, H.J.C.
2003-01-01
Active damping can be realised robustly through the use of a position actuator, a collocated force sensor, and control based on ‘Integral Force Feedback’ (IFF). Instead of a pure integrator, it is also possible to use a first-order lowpass-filter in the feedback loop (‘leaking IFF’). For both cases, the maximum achievable relative damping for a certain vibration mode can easily be predicted. If the achievable damping is too low, it is possible to improve this by means of ‘crosstalk-compensati...
11. The efficacy of a continuous quality improvement (CQI) method in a radiological department: comparison with non-CQI control material
To study the efficacy of continuous quality improvement (CQI) compared to ordinary management in an on-duty radiology department. Because of complaints regarding delivery of on-duty radiological services, an improvement was initiated simultaneously at two hospitals, at the HUCH (Helsinki University Central Hospital) utilising the CQI-method, and at the OUH (Oulu University Hospital) with a traditional management process. For the CQI project, a team was formed to evaluate the process with flow-charts, cause and effect diagrams, Pareto analysis and control charts. Interventions to improve the process were based on the results of these analyses. The team at the HUCH implemented the following changes: A radiologist was added to the evening shift between 15:00 - 22:00 and a radiographer was moved from the morning shift to 15:00 - 22:00. A clear improvement was achieved in the turn-around time, but in the follow-up some of the gains were lost. Only minimal changes were achieved at the OUH, where the intervention was based on traditional management processes. CQI was an effective method for improving the quality of performance of a radiology department compared with ordinary management methods, but some of this improvement may be subsequently lost without a continuous measurement system
12. Monitoring measurement tools: new methods for driving continuous improvements in fleet measurement uncertainty
Solecky, Eric; Archie, Chas; Sendelbach, Matthew; Fiege, Ron; Zaitz, Mary; Shneyder, Dmitriy; Strocchia-rivera, Carlos; Munoz, Andres; Rangarajan, Srinivasan; Muth, William; Brendler, Andrew; Banke, Bill; Schulz, Bernd; Hartig, Carsten; Hoeft, Jon-Tobias; Vaid, Alok; Kelling, Mark; Bunday, Benjamin; Allgair, John
2009-03-01
Ever shrinking measurement uncertainty requirements are difficult to achieve for a typical metrology toolset, especially over the entire expected life of the fleet. Many times, acceptable performance can be demonstrated during brief evaluation periods on a tool or two in the fleet. Over time and across the rest of the fleet, the most demanding processes often have measurement uncertainty concerns that prevent optimal process control, thereby limiting premium part yield, especially on the most aggressive technology nodes. Current metrology statistical process control (SPC) monitoring techniques focus on maintaining the performance of the fleet where toolset control chart limits are derived from a stable time period. These tools are prevented from measuring product when a statistical deviation is detected. Lastly, these charts are primarily concerned with daily fluctuations and do not consider the overall measurement uncertainty. It is possible that the control charts implemented for a given toolset suggest a healthy fleet while many of these demanding processes continue to suffer measurement uncertainty issues. This is especially true when extendibility is expected in a given generation of toolset. With this said, there is a need to continually improve the measurement uncertainty of the fleet until it can no longer meet the needed requirements at which point new technology needs to be entertained. This paper explores new methods in analyzing existing SPC monitor data to assess the measurement performance of the fleet and look for opportunities to drive improvements. Long term monitor data from a fleet of overlay and scatterometry tools will be analyzed. The paper also discusses using other methods besides SPC monitors to ensure the fleet stays matched; a set of SPC monitors provides a good baseline of fleet stability but it cannot represent all measurement scenarios happening in product recipes. The analyses presented deal with measurement uncertainty on non
13. Continuous improvement in the Industrial and Management Systems Engineering programme at Kuwait University
Aldowaisan, Tariq; Allahverdi, Ali
2016-07-01
This paper describes the process employed by the Industrial and Management Systems Engineering programme at Kuwait University to continuously improve the programme. Using a continuous improvement framework, the paper demonstrates how various qualitative and quantitative analyses methods, such as hypothesis testing and control charts, have been applied to the results of four assessment tools and other data sources to improve performance. Important improvements include the need to reconsider two student outcomes as they were difficult to implement in courses. In addition, through benchmarking and the engagement of Alumni and Employers, key decisions were made to improve the curriculum and enhance employability.
14. Integrating Essential Components of Quality Improvement into a New Paradigm for Continuing Education
Van Hoof, Thomas J.; Meehan, Thomas P.
2011-01-01
Continuing education (CE) that strives to improve patient care in a complex health care system requires a different paradigm than CE that seeks to improve clinician knowledge and competence in an educational setting. A new paradigm for CE is necessary in order to change clinician behavior and to improve patient outcomes in an increasingly…
15. An action research study; cultural differences impact how manufacturing organizations receive continuous improvement
National culture and organizational culture impact how continuous improvement methods are received, implemented and deployed by suppliers. Previous research emphasized the dominance of national culture over organizational culture. The countries studied included Poland, Mexico, China, Taiwan, South Korea, Estonia, India, Canada, the United States, the United Kingdom, and Japan. The research found that Canada was most receptive to continuous improvement, with China being the least receptive. The study found that organizational culture was more influential than national culture. Isomorphism and benchmarking is driving continuous-improvement language and methods to be more universally known within business. Business and management practices are taking precedence in driving change within organizations.
16. NUMBER OF SUCCESSIVE CYCLES NECESSARY TO ACHIEVE STABILITY OF SELECTED GROUND REACTION FORCE VARIABLES DURING CONTINUOUS JUMPING
Jasmes M.W. Brownjohn
2009-12-01
Full Text Available Because of inherent variability in all human cyclical movements, such as walking, running and jumping, data collected across a single cycle might be atypical and potentially unable to represent an individual's generalized performance. The study described here was designed to determine the number of successive cycles due to continuous, repetitive countermovement jumping which a test subject should perform in a single experimental session to achieve stability of the mean of the corresponding continuously measured ground reaction force (GRF variables. Seven vertical GRF variables (period of jumping cycle, duration of contact phase, peak force amplitude and its timing, average rate of force development, average rate of force relaxation and impulse were extracted on the cycle-by-cycle basis from vertical jumping force time histories generated by twelve participants who were jumping in response to regular electronic metronome beats in the range 2-2.8 Hz. Stability of the selected GRF variables across successive jumping cycles was examined for three jumping rates (2, 2.4 and 2.8 Hz using two statistical methods: intra-class correlation (ICC analysis and segmental averaging technique (SAT. Results of the ICC analysis indicated that an average of four successive cycles (mean 4.5 ± 2.7 for 2 Hz; 3.9 ± 2.6 for 2.4 Hz; 3.3 ± 2.7 for 2.8 Hz were necessary to achieve maximum ICC values. Except for jumping period, maximum ICC values took values from 0.592 to 0.991 and all were significantly (p < 0.05 different from zero. Results of the SAT revealed that an average of ten successive cycles (mean 10.5 ± 3.5 for 2 Hz; 9.2 ± 3.8 for 2.4 Hz; 9.0 ± 3.9 for 2.8 Hz were necessary to achieve stability of the selected parameters using criteria previously reported in the literature. Using 10 reference trials, the SAT required standard deviation criterion values of 0.49, 0.41 and 0.55 for 2 Hz, 2.4 Hz and 2.8 Hz jumping rates, respectively, in order to approximate
17. 78 FR 21879 - Improving 9-1-1 Reliability; Reliability and Continuity of Communications Networks, Including...
2013-04-12
... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Chapter I Improving 9-1-1 Reliability; Reliability and Continuity of Communications Networks, Including Broadband Technologies AGENCY: Federal Communications Commission. ACTION: Notice...
18. Government/contractor partnerships for continuous improvement. A Goddard Space Flight Center example
Tagler, Richard C.
1992-01-01
The efforts of a government organization and its major contractors to foster a continuous improvement environment which transcends the traditional government/contractor relationship is discussed. This relationship is aimed at communication, partnership, and trust - creating benefits for all involved.
19. 78 FR 69018 - Improving the Resiliency of Mobile Wireless Communications Networks; Reliability and Continuity...
2013-11-18
... COMMISSION 47 CFR Part 4 Improving the Resiliency of Mobile Wireless Communications Networks; Reliability and Continuity of Communications Networks, Including Broadband Technologies AGENCY: Federal Communications... Commission seeks comment on measures to promote the resiliency and transparency of mobile wireless...
20. Continuous improvement of outsourcing processess: the experience of an electric power distributor
Pinho, José Ocelo Maciel; Marques, Erico Veras; Melo, Francisco Vicente Sales
2012-01-01
The present work aims at analyzing how continuous improvement is developed in the outsourced processes of an electric power distribution company. The study brings a summary of outsourcing highlighting the complexity and difficulty of such a process as well as the importance of a partnership between taker and service provider. Results obtained indicate that in order continuously improve outsourced processes, essential factors must be consideredamong them: well defined service level agreements ...
1. "HY-CHANGE": AN HYBRID METHODOLOGY FOR CONTINUOUS PERFORMANCE IMPROVEMENT OF MANUFACTURING PROCESSES
Dassisti, Michele
2010-01-01
Abstract An hybrid methodology based on the joint recourse of Business Process An hybrid methodology for Continuous Performance Improvement (CPI) is presented, basically funded on the joint recourse of Business Process Reengineering (BPR) and Continuous Quality Improvement (CQI) principles and tools. The methodology (called HY-CHANGE) is conceived as a logical and technical support to the decision maker. It results in a number of recursive phases, where the rational and synchronous...
2. Emergency department triage: a program assessment using the tools of continuous quality improvement.
Cook, S; Sinclair, D
1997-01-01
An assessment was undertaken in the emergency department of a busy tertiary care center to illustrate the role of continuous quality improvement in the evaluation of an emergency triage program that utilizes the emergency medical attendant to provide triage. An evaluation team interviewed triage staff, charge nurses, internal customers, risk management, and the patient representative. A detailed review of staff job descriptions, organization charts, orientation manual, and physical facilities was conducted. A chart audit was completed on 100 triage notes. Direct observation was undertaken on nine occasions. An evaluation of the data gathered was performed using the tools of continuous quality improvement, and resulted in specific recommendations being made to improve the process of care. It was concluded that emergency medical attendants function very well in an emergency medicine triage system and the tools of continuous quality improvement can be applied to a clinical service to improve the quality of care. PMID:9404811
3. The continuous improvement of the Internal Audits Process assurance the effective compliance of ISO 17025:2005 requirements
Carina Di Candia
2011-04-01
Full Text Available Continuous Improvement Process started in LATU in 1996. The Impact was so important that covered all the organization. Nowadays LATU has almost all its processes certificated and most than 200 tests accredited. The Internal Audits process began in 1996 with an annual planning for all the laboratory's areas. For the UKAS accreditation in 1998, LATU improves the internal audits planning auditing not only the system but also the tests. In 1999 LATU was certified by SQS and accredited the calibrations by DKD. Since 2004 internal audits was managed as a process; in order to that was defined objectives, indicators, achievements and the necessary resources of the internal audit programme and process. The internal audit programme has a pre defined tri annual planning that includes all the laboratory areas. The results of the measures obtained till now demonstrate the improvement in the internal audit and all the laboratory processes. Auditors final staff increase their technical competence. As a consequence of managing the internal audits as a process, the internal communication has an important relevance to feedback the continuous improvement of the laboratory. This was evidence in a decrease of the documentaries non conformities, improvement of the calibrations and maintenance programme, optimization trainings and qualifications of the staff, common internal trainings, creation of a quality assurance team to improvement the tests control, improvement in the relationship with the support areas. Most of this requirements are included in ISO 17025:2005; that assurance the effective compliance of this standard.
4. Energy thrift and improved performance achieved through novel railway brake discs
A disc with radial vanes and circumferential pillars proves to be successful in operation and achieves energy efficiency improvements compared with those of traditional design. Cooling characteristics of this novel design are practically identical to the disc with tangential vanes but the equivalent aerodynamic (air pumping) losses are approximately 50% less. It is shown that these reductions in pumping losses can lead to substantial energy savings in train operations. When developing new designs and/or comparing different railway disc designs, the proposed disc cooling to aerodynamic efficiency ratio (ηv) was found to be a very useful parameter to assess. This 'efficiency ratio' - a ratio of convective power dissipation to aerodynamic power losses can help in achieving adequate balance of cooling efficiency and aerodynamic losses to suit particular application. The use of CFD is of enormous benefit in generating discs that fulfil these demanding requirements, with the spin rig being exceptionally useful for experimental work
5. Jointly achieving profitability and environmental outcomes: methane abatement from genetic improvement in the Australian beef industry
Alford, Andrew R.; Cacho, Oscar J.; Griffith, Garry R.; Hegarty, Roger S.
2006-01-01
Selection of cattle with greater feed efficiency is known to be profitable. Savings in southern Australian beef production systems of $6.55 per breeding cow per year have been estimated for selection for lower residual feed intake (RFI), and an additional saving of$4.34 per breeding cow per year may be achieved in feedlots. Greater feed efficiency is also expected to reduce methane emissions. A gene flow model was developed to simulate the spread of improved RFI genes through both a single h...
6. Creating Sustainable Education Projects in Roatán, Honduras through Continuous Process Improvement
Raven, Arjan; Randolph, Adriane B.; Heil, Shelli
2010-01-01
The investigators worked together with permanent residents of Roatán, Honduras on sustainable initiatives to help improve the island's troubled educational programs. Our initiatives focused on increasing the number of students eligible and likely to attend a university. Using a methodology based in continuous process improvement, we developed…
7. 14 CFR 21.7 - Continued airworthiness and safety improvements for transport category airplanes.
2010-01-01
... improvements for transport category airplanes. 21.7 Section 21.7 Aeronautics and Space FEDERAL AVIATION... § 21.7 Continued airworthiness and safety improvements for transport category airplanes. (a) On or... subchapter. (b) For new transport category airplanes manufactured under the authority of the FAA, the...
8. Modified surface loading process for achieving improved performance of the quantum dot-sensitized solar cells
Liu, Feng; Jin, Zhongxiu; Zhu, Jun; Xu, Yafeng; Zhou, Li; Dai, Songyuan
2016-06-01
Achieving high surface coverage of the colloidal quantum dots (QDs) on TiO2 films has been challenging for quantum dot-sensitized solar cells (QDSCs). Herein, a general surface engineering approach was proposed to increase the loading of these QDs. It was found that S2- treatment/QD re-uptake process can significantly improve the attachment of the QDs on TiO2 films. Surface concentration of the QDs was improved by ∼60%, which in turn greatly enhances light absorption and decreases carrier recombination in QDSCs. Ensuing QDSCs with optimized QD loading exhibit a power conversion efficiency of 3.66%, 83% higher than those fabricated with standard procedures.
9. Integrated product and process system with continuous improvement in the auto parts industry
I.B. Silva; G.F. Batalha; M. Stipkovik Filho; F.Z. Ceccarelli; J.B. Anjos; M. Fesz
2009-01-01
Purpose: Quality systems (QS) update must be based on the enterprise organization to assure customer satisfaction, as Deming, Juran and Feigenbaum did in their time, to seek improvement processes to reach high quality performance. This way, the proposal of this paper is the development of quality system integration model of product and process with continuous improvement.Design/methodology/approach: To reach this goal, a Brazilian automotive parts quality system was improved through the Compu...
10. Adhesion improvement of fibres by continuous plasma treatment at atmospheric pressure
Kusano, Yukihiro; Løgstrup Andersen, Tom; Sørensen, Bent F.;
2013-01-01
Carbon fibres and ultra-high-molecular-weight polyethylene (UHMWPE) fibres were continuously treated by a dielectric barrier discharge plasma at atmospheric pressure for adhesion improvement with epoxy resins. The plasma treatment improved wettability, increased the oxygen containing polar...... functional groups at the surface, and subsequently improved adhesion to the epoxy and fracture resistance of epoxy composites. Hansen solubility parameters (HSP), quantitatively describing physical interactions among molecules, were measured for the UHMWPE fibre surfaces. The result identifies two distinct...
11. A physical education trial improves adolescents' cognitive performance and academic achievement: the EDUFIT study.
Ardoy, D N; Fernández-Rodríguez, J M; Jiménez-Pavón, D; Castillo, R; Ruiz, J R; Ortega, F B
2014-02-01
To analyze the effects of an intervention focused on increasing the time and intensity of Physical Education (PE), on adolescents' cognitive performance and academic achievement. A 4-month group-randomized controlled trial was conducted in 67 adolescents from South-East Spain, 2007. Three classes were randomly allocated into control group (CG), experimental group 1 (EG1) and experimental group 2 (EG2). CG received usual PE (two sessions/week), EG1 received four PE sessions/week and EG2 received four PE sessions/week of high intensity. Cognitive performance (non-verbal and verbal ability, abstract reasoning, spatial ability, verbal reasoning and numerical ability) was assessed by the Spanish Overall and Factorial Intelligence Test, and academic achievement by school grades. All the cognitive performance variables, except verbal reasoning, increased more in EG2 than in CG (all P improved more than EG1, without differences between EG1 and CG. Increased PE can benefit cognitive performance and academic achievement. This study contributes to the current knowledge by suggesting that the intensity of PE sessions might play a role in the positive effect of physical activity on cognition and academic success. Future studies involving larger sample sizes should confirm or contrast these preliminary findings. PMID:23826633
12. Employee Perceptions of Progress with Implementing a Student-Centered Model of Institutional Improvement: An Achieving the Dream Case Study
Cheek, Annesa LeShawn
2011-01-01
Achieving the Dream is a national initiative focused on helping more community college students succeed, particularly students of color and low-income students. Achieving the Dream's student-centered model of institutional improvement focuses on eliminating gaps and raising student achievement by helping institutions build a culture of evidence…
13. From Guide to Practice: Improving Your After School Science Program to Increase Student Academic Achievement
Taylor, J.
2013-12-01
Numerous science organizations, such as NASA, offer educational outreach activities geared towards after school. For some programs, the primary goal is to grow students' love of science. For others, the programs are also intended to increase academic achievement. For those programs looking to support student learning in out-of-school time environments, aligning the program with learning during the classroom day can be a challenge. The Institute for Education Sciences, What Works Clearinghouse, put together a 'Practice Guide' for maximizing learning time beyond the regular school day. These practice guides provide concrete recommendations for educators supported by research. While this guide is not specific to any content or subject-area, the recommendations provided align very well with science education. After school science is often viewed as a fun, dynamic environment for students. Indeed, one of the recommendations to ensure time is structured according to students' needs is to provide relevant and interesting experiences. Given that our after school programs provide such creative environments for students, what other components are needed to promote increased academic achievement? The recommendations provided to academic achievement, include: 1. Align Instruction, 2. Maximize Attendance and Participation, 3. Adapt Instruction, 4. Provide Engaging Experiences, and 5. Evaluate Program. In this session we will examine these five recommendations presented in the Practice Guide, discuss how these strategies align with science programs, and examine what questions each program should address in order to provide experiences that lend themselves to maximizing instruction. Roadblocks and solutions for overcoming challenges in each of the five areas will be presented. Jessica Taylor will present this research based on her role as an author on the Practice Guide, 'Improving Academic Achievement in Out-of-School Time' and her experience working in various informal science
14. A Continuous Quality Improvement Approach to Improving Clinical Practice in the Areas of Sedation, Analgesia, and Neuromuscular Blockade.
Arbour, Richard
2003-01-01
A continuous improvement approach to upgrading nurses' administration of sedatives and analgesics included (1) data collection from charts, shift reports, rounds, and bedside examinations; (2) identification of clinical issues and needs; and (3) design of interventions using on teaching moments, competency-based modules, and instruction during…
15. Real Estate Continuing Education: Rent Seeking or Improvement in Service Quality?
Benjamin Powell; Evgeny Vorotnikov
2012-01-01
Massachusetts adopted a continuing education component to its licensing requirements for real estate agents in 1999. The Massachusetts Association of Realtors lobbied for this change claiming it would enhance the quality of service for the public. Our regression analysis fails to find any improvement in the quality of service as measured by complaints to the real estate licensing board. We do find that the adoption of continuing education reduced the number of licensed active agents by 39 to ...
16. Problem Lah! Learning to Tell the Story of Continuous Assessment and Improvement
Hanken, Tamera
2014-01-01
To succeed organizations rely on the purposeful application of the management functions, planning, organizing, leading and controlling, i.e., assessment. Assessment involves the collection and analysis of service and performance data to inform planning, organizing and leading-- opening the door to a culture of assessment and continuous improvement. Like other organizations responding to ever challenging economies and ever changing customer expectations, libraries are examining continuous impr...
17. Improvement in performance of DM plant, secondary systems for achieving chemistry performance indicator of KGS-3 and 4
Kaiga Generating Station (KGS)-3 and 4 has two 220 MWe Pressurized Heavy Water Reactors. It uses Heavy water as moderator and coolant and DM (De-mineralized) water in secondary system for steam generation. Raw water for plant is taken from Kali River. Raw water is first treated in pretreatment plant and Dual media filter for turbidity removal. Chlorination is carried out for control of micro-organism. DM water is makeup to feed water which is the input to Steam Generator for production of steam for power generation. Continuous blow down through Boiler blow down (BBD) IX column is carried out to control Steam Generator (SG) chemistry. It was decided by Nuclear Power Corporation India Limited (NPCIL) management to calculate Chemistry Performance Indicator of KGS secondary system and it was found 2.6 which was much higher than Standard and best achievable value of 1.0. Detailed analysis was carried out and improvements required in DM plant, water treatment plant, BBD IX column, Steam Generator etc were identified and plan was made for improvement. Turbidity of filter water was brought below 2.0 NTU. Many changes were incorporated in DM plant. Regenerate concentration, regeneration levels and regeneration procedures were modified. Resin replacement frequencies were fixed and brine treatment of anion resin was started at regular interval. For DM water production two mixed resin columns in series were used in place of earlier one mixed resin column. By these modifications DM water Chloride, Sodium and Sulphate were brought <1.0 ppb from earlier 5-10 ppb. Regeneration procedure of BBD IX column were standardized. Service life of BBD IX column was fixed and was isolated from service before exhaustion. Design deficiencies of BBD IX column was rectified by applying innovative idea. Online sodium analyzer was installed in boiler blow down line. By implementing these improvements Chemistry Performance Indicator of both units were brought down to 1.0, which is standard and best
18. Improving quality of sample entropy estimation for continuous distribution probability functions
Miśkiewicz, Janusz
2016-05-01
Entropy is a one of the key parameters characterizing state of system in statistical physics. Although, the entropy is defined for systems described by discrete and continuous probability distribution function (PDF), in numerous applications the sample entropy is estimated by a histogram, which, in fact, denotes that the continuous PDF is represented by a set of probabilities. Such a procedure may lead to ambiguities and even misinterpretation of the results. Within this paper, two possible general algorithms based on continuous PDF estimation are discussed in the application to the Shannon and Tsallis entropies. It is shown that the proposed algorithms may improve entropy estimation, particularly in the case of small data sets.
19. Comprehensive approach to improving maternal health and achieving MDG 5: report from the mountains of Lesotho.
Hind Satti
Full Text Available BACKGROUND: Although it is now widely recognized that reductions in maternal mortality and improvements in women's health cannot be achieved through simple, vertical strategies, few programs have provided successful models for how to integrate services into a comprehensive program for maternal health. We report our experience in rural Lesotho, where Partners In Health (PIH in partnership with the Ministry of Health and Social Welfare implemented a program that provides comprehensive care of pregnant women from the community to the clinic level. METHODS: Between May and July 2009, PIH trained 100 women, many of whom were former traditional birth attendants, to serve as clinic-affiliated maternal health workers. They received performance-based incentives for accompanying pregnant women during antenatal care (ANC visits and facility-based delivery. A nurse-midwife provided ANC and delivery care and supervised the maternal health workers. To overcome geographic barriers to delivering at the clinic, women who lived far from the clinic stayed at a maternal lying-in house prior to their expected delivery dates. We analyzed data routinely collected from delivery and ANC registers to compare service utilization before and after implementation of the program. RESULTS: After the establishment of the program, the average number first ANC visits increased from 20 to 31 per month. The clinic recorded 178 deliveries in the first year of the program and 216 in the second year, compared to 46 in the year preceding the program. During the first two years of the program, 49 women with complications were successfully transported to the district hospital, and no maternal deaths occurred among the women served by the program. CONCLUSIONS: Our results demonstrate that it is possible to achieve dramatic improvements in the utilization of maternal health services and facility-based delivery by strengthening human resource capacity, implementing active follow-up in the
20. Expanding Continuous Quality Improvement Capacity in the Medical Intensive Care Unit: Prehealth Volunteers as a Solution.
Priest, Kelsey C; Lobingier, Hannah; McCully, Nancy; Lombard, Jackie; Hansen, Mark; Uchiyama, Makoto; Hagg, Daniel S
2016-01-01
Health care delivery systems are challenged to support the increasing demands for improving patient safety, satisfaction, and outcomes. Limited resources and staffing are common barriers for making significant and sustained improvements. At Oregon Health & Science University, the medical intensive care unit (MICU) leadership team faced internal capacity limitations for conducting continuous quality improvement, specifically for the implementation and evaluation of the mobility portion of an evidence-based care bundle. The MICU team successfully addressed this capacity challenge using the person power of prehealth volunteers. In the first year of the project, 52 trained volunteers executed an evidence-based mobility intervention for 305 critically ill patients, conducting more than 200 000 exercise repetitions. The volunteers contributed to real-time evaluation of the project, with the collection of approximately 26 950 process measure data points. Prehealth volunteers are an untapped resource for effectively expanding internal continuous quality improvement capacity in the MICU and beyond. PMID:27031356
1. Management of continual improvement for facilities and activities: A structured approach
In recent years there has been an upward trend in the safety and operational performance of nuclear installations. Safe, efficient operation is their goal. Continual improvement of the processes of organizations has led to enhanced safety performance and efficiency benefits such as cost reductions and improved cycle times. Many organizations have experienced significant cost improvement largely by or through better financial management and a common drive to reduce costs brought on by commercial pressures. Without the use of a structured methodology to identify and implement improvements, changes to an organization to reduce costs through cutting staff and activities could eventually fail to produce the desired changes and even have a negative effect on safety and overall performance. The following fundamental principles are considered essential to the effective introduction of structured continual improvement: - Long term commitment from senior management throughout the entire organization; - The implementation in the organization of a process management approach such as that advocated by IAEA Safety Standards, ISO 9001, Malcolm Baldridge National Quality Award and European Foundation for Quality Management Business Excellence model; - The alignment of the processes with the objectives of the organization through the organization's business plan; - The utilization by Management of the process information as an input to managing the organization; - The employment of the information derived from the process performance to identify and prioritize the processes that require improvement; - The active participation of all staff of the organization to using its processes in order to contribute to continual process improvement (CPI). This publication defines a structured approach for continual improvement and focuses on the way an organization can improve its processes. It is recognized that there are many different approaches and methods available in the marketplace to
2. Using a Client Survey to Support Continuous Improvement: An Australian Case Study in Managing Change
Besch, Janice
2014-01-01
With the arrival of online survey tools that are low-cost, readily available and easy to administer, all organizations have access to one of the most effective mechanisms for determining quality improvement priorities and measuring progress towards achieving those priorities over time. This case study outlines the use made of this simple tool by a…
3. On the Intractability of the Achievement Gap in Urban Schools and the Discursive Practice of Continuing Racial Discrimination.
English, Fenwick W.
2002-01-01
Achievement gaps between minority and white students may never be resolved because they are an artifact of a measurement process that uses flawed tests to assess student progress. IQ and achievement testing have always shown that socioeconomic status (SES) is critical in explaining test score variance. SES is part of the concept of cultural…
4. Contrasting continuous quality improvement, Six Sigma, and lean management for enhanced outcomes in US hospitals
Charles R. Gowen III; Kathleen L. McFadden; Sriranjita Settaluri
2012-01-01
Rapidly rising healthcare costs, partially due to preventable medical errors, have led hospitals to redouble their process improvement (PI) efforts. The purpose of this paper is to examine how PI initiatives mediate the effect of medical error sources to enhance three hospital outcomes (patient safety, operational effectiveness, and competitiveness). Drawing from Dynamic Capabilities Theory, the authors develop a framework to explore three PI initiatives: Continuous Quality Improvement (CQI),...
5. The Dorset Seedcorn Project: interprofessional learning and continuous quality improvement in primary care.
Wilcock, Peter M; Campion-Smith, Charles; Head, Michael
2002-01-01
There is a need to develop models of practice-based learning that are effective in bringing about improvement in the quality of care that patients receive. This paper describes a facilitated practice-based project where five general practices in Dorset formed interprofessional teams that worked over a six-month period using a continuous quality improvement (CQI) approach to make a change in areas of importance to them. All the teams completed the project and planned and implemented demonstrab...
6. The Stories Clinicians Tell: Achieving High Reliability and Improving Patient Safety.
Cohen, Daniel L; Stewart, Kevin O
2016-01-01
The patient safety movement has been deeply affected by the stories patients have shared that have identified numerous opportunities for improvements in safety. These stories have identified system and/or human inefficiencies or dysfunctions, possibly even failures, often resulting in patient harm. Although patients' stories tell us much, less commonly heard are the stories of clinicians and how their personal observations regarding the environments they work in and the circumstances and pressures under which they work may degrade patient safety and lead to harm.If the health care industry is to function like a high-reliability industry, to improve its processes and achieve the outcomes that patients rightly deserve, then leaders and managers must seek and value input from those on the front lines-both clinicians and patients. Stories from clinicians provided in this article address themes that include incident identification, disclosure and transparency, just culture, the impact of clinical workload pressures, human factors liabilities, clinicians as secondary victims, the impact of disruptive and punitive behaviors, factors affecting professional morale, and personal failings. PMID:26580146
7. (Mis)Perceptions of Continuing Education: Insights from Knowledge Translation, Quality Improvement, and Patient Safety Leaders
Kitto, Simon C.; Bell, Mary; Goldman, Joanne; Peller, Jennifer; Silver, Ivan; Sargeant, Joan; Reeves, Scott
2013-01-01
Introduction: Minimal attention has been given to the intersection and potential collaboration among the domains of continuing education (CE), knowledge translation (KT), quality improvement (QI), and patient safety (PS), despite their overlapping objectives. A study was undertaken to examine leaders' perspectives of these 4 domains and their…
8. Motivational Interviewing (MINT) Improves Continuous Positive Airway Pressure (CPAP) Acceptance and Adherence: A Randomized Controlled Trial
Olsen, Sara; Smith, Simon S.; Oei, Tian P. S.; Douglas, James
2012-01-01
Objective: Adherence to continuous positive airway pressure (CPAP) therapy for obstructive sleep apnoea (OSA) is poor. We assessed the effectiveness of a motivational interviewing intervention (motivational interview nurse therapy [MINT]) in addition to best practice standard care to improve acceptance and adherence to CPAP therapy in people with…
9. Cummins' Framework as a Tool for Continuous Improvement of SLL Instruction
Montgomery, Joel R.
2008-01-01
This working paper will explore the usefulness of Cummins' framework relating language proficiency to academic performance (1983) as a reflection and planning tool for continuous improvement of second language learning (SLL) instruction. SLL activities designed for a Language Experience intervention class for seventh and eighth grade English…
Medina Araujo, Jacqueline
2013-01-01
This capstone project examines how an elementary school principal and her leadership team transformed Leadership Prep Academy in Capital City into a collaborative, high performing community school. This five-year process of continuous improvement involved engaging students, staff, parents, and members of the community in developing a culture of…
11. Record of Assessment Moderation Practice (RAMP): Survey Software as a Mechanism of Continuous Quality Improvement
Johnson, Genevieve Marie
2015-01-01
In higher education, assessment integrity is pivotal to student learning and satisfaction, and, therefore, a particularly important target of continuous quality improvement. This paper reports on the preliminary development and application of a process of recording and analysing current assessment moderation practices, with the aim of identifying…
12. Fostering Continuous Improvement and Learning through Peer Assessment: Part of an Integral Model of Assessment
Davis, Nancy T.; Kumtepe, Evrim Genc; Aydeniz, Mehmet
2007-01-01
Assessment is a critical component of educational practices and thus impacts educational reform efforts. This article reviews and considers assessment from 2 perspectives: a focus on accountability and a focus on continuous improvement. A class of preservice and practicing science teachers explored notions of assessment while experiencing peer…
13. Factors Influencing Team Performance in a Continuous Quality Improvement Process in the Wisconsin Technical College System
Pietz, Victoria Lynn
2014-01-01
Continuous Quality Improvement (CQI) programs are growing in popularity in higher education settings and a key component is the use of work groups, which require active employee involvement. The problem addressed in this research was the lack of employee engagement in the Quality Review Process (QRP), which is a statewide CQI model developed by…
14. Beyond the Numbers: Data Use for Continuous Improvement of Programs Serving Disconnected Youth
Pate, Austin; Lerner, Jennifer Brown; Browning, Andrea
2012-01-01
This publication is a series of in-depth case studies to examine how three programs which serve a disconnected youth population are utilizing data as a tool for continuous program improvement and ongoing accountability. The report features the following programs: (1) Roca, an organization in Massachusetts which engages the highest-risk youth in…
15. Relationships between Climate, Process, and Performance in Continuous Quality Improvement Groups
Wilkens, Roxanne; London, Manuel
2006-01-01
This study examined relationships between group climate (participants' learning orientation, feelings of psychological safety, and self-disclosure), process (feedback and conflict), and performance in continuous quality improvement groups. Forty-nine participants in eight hospital groups were surveyed as the groups neared completion. Groups were…
16. Improving the provision of pregnancy care for Aboriginal and Torres Strait Islander women: a continuous quality improvement initiative
Gibson-Helm, Melanie E.; Rumbold, Alice R; Teede, Helena J; Ranasinha, Sanjeeva; Bailie, Ross S; Jacqueline A. Boyle
2016-01-01
Background Australian Aboriginal and Torres Strait Islander (Indigenous) women are at greater risk of adverse pregnancy outcomes than non-Indigenous women. Pregnancy care has a key role in identifying and addressing modifiable risk factors that contribute to adverse outcomes. We investigated whether participation in a continuous quality improvement (CQI) initiative was associated with increases in provision of recommended pregnancy care by primary health care centers (PHCs) in predominantly I...
17. Continuous Cognitive Tasks Improve Postural Control Compared to Discrete Cognitive Tasks.
Lajoie, Yves; Richer, Natalie; Jehu, Deborah A; Tran, Ylan
2016-01-01
Research suggests that postural control synergies are sensitive to cognitive manipulations; however, the impact of different types of cognitive tasks on postural control remains inconclusive. The authors examined the effect of discrete and continuous tasks on postural control. Sixteen healthy young adults (M age = 22.7 ± 2.2 years) stood with feet together on a force platform while performing randomly assigned discrete and continuous cognitive tasks. Results demonstrated marked improvements in the area of 95% confidence ellipse and the standard deviation of the center of pressure in the anterior-posterior and medial-lateral directions for continuous compared to discrete tasks. This reinforces the notion that continuous tasks are sufficient in providing less opportunity to consciously attend to postural control, thereby facilitating automatic postural control. PMID:26503343
18. Continuous improvement in dietetics education with a regional advisory board: a model that works.
Martin, Rose L
2003-08-01
Continuous improvement has been a focus of business and health care for years. The Commission on Accreditation for Dietetics Education has also identified the need for continuous improvement in dietetics education programs and requires them to seek outside counsel to help accomplish it. Most dietetics education programs develop advisory boards to provide this outside counsel, but finding individuals to commit to an ongoing advisory board can be challenging. Dietetics internship directors from dietetics practicum programs throughout Arizona created the Arizona Dietetic Practicum Advisory Committee (AzDPAC), which uses suggestions from preceptors, interns, and committee members to generate ideas for improvement. Since the conception of AzDPAC both tangible and intangible outcomes have occurred. Tangible outcomes include better coordination among programs, development of a combined annual affiliate meeting, standardization of forms, creation of a combined "Clinical Bootcamp," development of a Web page describing all programs, and better networking among interns from different programs. In addition, AzDPAC improved cooperation and sharing of expertise and created an available group of peers for new directors. An advisory committee of regional program directors is a model that works in providing dietetics education programs with ongoing outside counsel and ideas for continuous improvement. PMID:12891153
19. Independent assessment to continue improvement: Implementing statistical process control at the Hanford Site
A Quality Assurance independent assessment has brought about continued improvement in the PUREX Plant surveillance program at the Department of Energy's Hanford Site. After the independent assessment, Quality Assurance personnel were closely involved in improving the surveillance program, specifically regarding storage tank monitoring. The independent assessment activities included reviewing procedures, analyzing surveillance data, conducting personnel interviews, and communicating with management. Process improvement efforts included: (1) designing data collection methods; (2) gaining concurrence between engineering and management, (3) revising procedures; and (4) interfacing with shift surveillance crews. Through this process, Statistical Process Control (SPC) was successfully implemented and surveillance management was improved. The independent assessment identified several deficiencies within the surveillance system. These deficiencies can be grouped into two areas: (1) data recording and analysis and (2) handling off-normal conditions. By using several independent assessment techniques, Quality Assurance was able to point out program weakness to senior management and present suggestions for improvements. SPC charting, as implemented by Quality Assurance, is an excellent tool for diagnosing the process, improving communication between the team members, and providing a scientific database for management decisions. In addition, the surveillance procedure was substantially revised. The goals of this revision were to (1) strengthen the role of surveillance management, engineering and operators and (2) emphasize the importance of teamwork for each individual who performs a task. In this instance we believe that the value independent assessment adds to the system is the continuous improvement activities that follow the independent assessment. Excellence in teamwork between the independent assessment organization and the auditee is the key to continuing improvement
20. Development of a handoff continuity score to improve pediatric ICU physician schedule design for enhanced physician and patient continuity
Smalley, Hannah K; Keskinocak, Pinar; Vats, Atul
2011-01-01
Introduction Few studies investigate the benefits of familiarity or continuity during physician-to-physician handoff of inpatients. Factors such as how recently physicians (MDs) have worked and successive days caring for patients increase continuity, and thus could lead to enhanced handoff efficiency. Evaluating the efficacy of MD scheduling to enhance continuity is currently subjective. Methods An MD group consisting of 9 attending physicians and 7 fellows redesigned its pediatric intensive ...
1. Improving Science Achievement and Attitudes of Students With and Without Learning Disabilities
Sanders-White, Pamela
The primary purpose of this study was to investigate the effect of structured note-taking compared to traditional note-taking on the acquisition of scientific knowledge for students with and without learning disabilities (LD) and students with reading difficulties (RD). An additional purpose was to examine whether the two note-taking methods affected students' attitudes toward science. The sample population consisted of 203 fifth grade students across four public schools in the southern area of the United States. A standardized instrument aligned to Florida's science standards was used to measure the acquisition of scientific knowledge and the Test of Science-Related Attitudes (TOSRA) was used to measure seven distinct science-related attitudes. For meaningful analyses, students with LD and students with RD were collapsed to form a single group due to the small numbers of participants in each of the subgroups; the collapsed group was referred to as "low achievers." A three-way repeated measures ANOVA was conducted to determine the effects of the pretest-posttest Science Interim assessment by group, type of student, and gender. The pretest-posttest Science Interim assessment scores were the within-group factor, while group, type of student, and gender were the between-groups factors. Results revealed that there was a significant interaction between the pretest-posttest Science Interim assessment and group, F(1, 191) = 9.320, p = .003, indicating that scientific knowledge scores increased for the experimental group, but decreased for the control group. Results also indicated that there was a significant three-way interaction between the pretest-posttest Science Interim assessment, group, and gender, F(1, 191) = 5.197, p = .024, showing that all participants in the experimental group improved their scores; while in the control group, female scores decreased and male scores increased. Participants in the experimental and control groups did not show improved attitudes
2. How Visual Management for Continuous Improvement Might Guide and Affect Hospital Staff: A Case Study.
Ulhassan, Waqar; von Thiele Schwarz, Ulrica; Westerlund, Hugo; Sandahl, Christer; Thor, Johan
2015-01-01
Visual management (VM) tools such as whiteboards, often employed in Lean thinking applications, are intended to be helpful in improving work processes in different industries including health care. It remains unclear, however, how VM is actually applied in health care Lean interventions and how it might influence the clinical staff. We therefore examined how Lean-inspired VM using whiteboards for continuous improvement efforts related to the hospital staff's work and collaboration. Within a case study design, we combined semistructured interviews, nonparticipant observations, and photography on 2 cardiology wards. The fate of VM differed between the 2 wards; in one, it was well received by the staff and enhanced continuous improvement efforts, whereas in the other ward, it was not perceived to fit in the work flow or to make enough sense in order to be sustained. Visual management may enable the staff and managers to allow communication across time and facilitate teamwork by enabling the inclusion of team members who are not present simultaneously; however, its adoption and value seem contingent on finding a good fit with the local context. A combination of continuous improvement and VM may be helpful in keeping the staff engaged in the change process in the long run. PMID:26426324
3. Longitudinal Analysis of the Role of Perceived Self-Efficacy for Self-Regulated Learning in Academic Continuance and Achievement
Caprara, Gian Vittorio; Fida, Roberta; Vecchione, Michele; Del Bove, Giannetta; Vecchio, Giovanni Maria; Barbaranelli, Claudio; Bandura, Albert
2008-01-01
The present study examined the developmental course of perceived efficacy for self-regulated learning and its contribution to academic achievement and likelihood of remaining in school in a sample of 412 Italian students (48% males and 52% females ranging in age from 12 to 22 years). Latent growth curve analysis revealed a progressive decline in…
4. The Continued Evaluation of Voucher Impact on the Achievement of Elementary Students in a Majority African American Public School District
Metcalf, Kim K.; Boone, William J.; Legan, Natalie A.; Paul, Kelli M.
Vouchers for students in urban school districts may promote the increased participation of underrepresented groups in the fields of science and engineering in at least two ways: (a) by optimizing the achievement of students who use vouchers and (b) by expanding the scope of educational and curricular options available to students. Presently, nearly 5,000 children in Cleveland, Ohio, attend private schools with publicly funded vouchers. This study presents the results of evaluating the achievement of a cohort of these students from the fall of first grade to the spring of fourth grade. For public school students, first grade seems to be a time during which they catch up with peers who attend private schools with vouchers. The analysis of data using adjusted measures suggests no differences in achievement from first grade to fourth grade with respect to achievement in many content areas. The use of unadjusted measures suggests possible differences with respect to fourth grade reading (with voucher students performing at a statistically higher level than their peers). The present data set neither clearly supports nor refutes the use of vouchers.
5. Harnessing the genetics of the modern dairy cow to continue improvements in feed efficiency.
VandeHaar, M J; Armentano, L E; Weigel, K; Spurlock, D M; Tempelman, R J; Veerkamp, R
2016-06-01
Feed efficiency, as defined by the fraction of feed energy or dry matter captured in products, has more than doubled for the US dairy industry in the past 100 yr. This increased feed efficiency was the result of increased milk production per cow achieved through genetic selection, nutrition, and management with the desired goal being greater profitability. With increased milk production per cow, more feed is consumed per cow, but a greater portion of the feed is partitioned toward milk instead of maintenance and body growth. This dilution of maintenance has been the overwhelming driver of enhanced feed efficiency in the past, but its effect diminishes with each successive increment in production relative to body size and therefore will be less important in the future. Instead, we must also focus on new ways to enhance digestive and metabolic efficiency. One way to examine variation in efficiency among animals is residual feed intake (RFI), a measure of efficiency that is independent of the dilution of maintenance. Cows that convert feed gross energy to net energy more efficiently or have lower maintenance requirements than expected based on body weight use less feed than expected and thus have negative RFI. Cows with low RFI likely digest and metabolize nutrients more efficiently and should have overall greater efficiency and profitability if they are also healthy, fertile, and produce at a high multiple of maintenance. Genomic technologies will help to identify these animals for selection programs. Nutrition and management also will continue to play a major role in farm-level feed efficiency. Management practices such as grouping and total mixed ration feeding have improved rumen function and therefore efficiency, but they have also decreased our attention on individual cow needs. Nutritional grouping is key to helping each cow reach its genetic potential. Perhaps new computer-driven technologies, combined with genomics, will enable us to optimize management for
6. THE ASSESSMENT METHODOLOGIES PTELR, ADRI AND CAE – THREE METHODOLOGIES FOR COORDINATING THE EFFORTS TO IMPROVE THE ORGANIZATIONAL PROCESSES TO ACHIEVE EXCELLENCE
Cristina Raluca POPESCU
2015-07-01
Full Text Available In the paper “The Assessment Methodologies PTELR, ADRI and CAE – Three Methodologies for Coordinating the Efforts to Improve the Organizational Processes to Achieve Excellence” the authors present the basic features of the assessment methodologies PTELR, ADRI and CAE that are designed to coordinate the efforts to improve the organizational processes in order to achieve excellence. In the first part of the paper (the introduction of the paper, the authors present the general background concerning the performance of management business processes and the importance of achieving excellence and furthermore correctly assessing/evaluating it. Aspects such as quality, quality control, quality assurance, performance and excellence are brought into discussion in the context generated by globalization, new technologies and new business models. Moreover, aspects regarding the methods employed to ensure the quality, maintaining it and continuous improvements, as well as total quality management, are also main pillars of this current research. In the content of the paper (the assessment methodologies PTELR, ADRI and CAE – as methodologies for coordinating the efforts to improve the organizational processes to achieve excellence, the authors describe the characteristics of the assessment methodologies PTELR, ADRI and CAE from a theoretical point of view.
7. Successful treatment of Depot Medroxyprogesterone acetate-related vaginal bleeding improves continuation rates in Adolescents
Kristin M. Rager
2006-01-01
Full Text Available High discontinuation rates for depot medroxyprogesterone acetate (DMPA in adolescents may contribute to the number of unintended pregnancies. Many cite vaginal bleeding as a reason for discontinuing DMPA use. In this study, we attempted to determine if treating DMPA-associated vaginal bleeding with monophasic oral contraceptive pills (OCP raised continuation rates. A total of 131 patients who reported vaginal bleeding while on DMPA were included in this study and 83 were treated with monophasic OCP. Of those who received OCP, 38.7% reported that vaginal bleeding stopped completely, 51.8% reported that vaginal bleeding stopped temporarily, and 6.0% reported no change. Overall, 94% of enrolled patients who received OCP as a treatment for DMPA-associated vaginal bleeding continued DMPA use. Our findings indicate that vaginal bleeding due to DMPA can be successfully treated, leading to improvement in continuation rates.
8. Organisational learning and continuous improvement of health and safety in certified manufacturers
Granerud, Lise; Rocha, Robson Sø
2011-01-01
processes. The model is applied to five cases from a qualitative study of Danish manufacturers with certified health and safety management systems. The cases illustrate the wide variation in health and safety management among certified firms. Certification is found to support lower levels of continuous......Certified management systems have increasingly been applied by firms in recent decades and now cover the management of health and safety, principally through the OHSAS 18001 standard. In order to become certified, firms must not only observe the relevant legislation, but also improve performance...... and raise goals within health and safety on a continuous basis. The article examines how certified occupational and health management systems influence this process to evaluate how far they hinder or support learning. It presents a model with which it is possible to identify and analyse improvement...
9. The continuous improvement in quality management for nuclear fuel manufacturing in CNNC
The nuclear fuel plant has been keeping good records in quality. Only one pot failure has been found in the fuels loaded in the reactors at more than ten years. The paper describes quality management in nuclear fuel manufacturing and focuses on the continuous improvement on quality system and process by running the quality management system, process by quality control group, and data analyze, the requirements and the improvements for the quality system, the measurement system and the standardization system, the importance of clearance system. It also describes the future plans in quality management
10. Continuous Plasma Treatment of Ultra-High-Molecular-Weight Polyethylene (UHMWPE) Fibres for Adhesion Improvement
Teodoru, Steluta; Kusano, Yukihiro; Rozlosnik, Noemi;
2009-01-01
A dielectric barrier discharge in Ar, He, He/O2, N2 or O2 at atmospheric pressure was used for the continuous plasma treatment of UHMWPE fibres. The influence of the input power of the discharge and the gas flow rate on surface modification is studied with the aim of adhesion improvement. Surface...... characterization using X-ray photoelectron spectroscopy and atomic force microscopy shows a significant increase in polar functional groups and roughness at the surfaces after plasma treatment, indicating that adhesive properties can be improved....
11. Development of a team-based framework for conducting self-assessment of Continuous Improvement
Jørgensen, Frances; Gertsen, Frank; Boer, Harry
2004-01-01
The study presented in this article is based on two basic premises. First, successful continuous improvement (CI) is dependent on shop floor level involvement and participation in improvement efforts. Second, the term "self-assessment" clearly implies that those whose performance is being measure......, the study shows how these principles relate to the teams' own work processes, and a deeper understanding of their organization's strategy and objectives......., and who are involved in conducting the assessment process. Excerpts from longitudinal case studies in a single Danish manufacturing organization demonstrate how teams involved in the process of conducting self-assessment of CI developed a better understanding of the basic principles of CI. Furthermore...
12. Air quality continued to improve in 2014, but progress are still needed
The improvement in air quality that began some years ago continued. Average concentrations of pollutants decreased and exceedance of thresholds for protection of health was observed in fewer areas. Progress was, notably, the result of efforts made to reduce emissions, something made more difficult by the number and variety of sources of pollution. These improvements were, however, fragile as they were partially dependent on weather conditions. 2014 was, thus, marked by an important episode of particulate pollution. In addition, the progress made was not sufficient to bring France into full compliance with European standards, as was also the case for other European countries. (author)
13. An Experimental Investigation to Facilitate an Improvement in the Design of an Electromagnetic Continuous Casting Mould
Lintao Zhang
2016-04-01
Full Text Available An electromagnetic continuous casting mould designed is proposed with a non-uniform slit distribution structure. This design has aimed to reduce the number of slits so that the mould’s strength is enhanced, whilst maintaining a similar metallurgy effect. In this paper, the metallurgy effect for the designed mould is investigated through the magnetic field distribution along the casting direction, the uniformity feature in the vicinity of the meniscus region, the temperature variation of the molten alloy pool and the mould wall. The results show that the designed mould achieved a similar effect as compared to the original mould; however, the configuration is simplified. This research highlights the topic of mould structure optimization, which would enable the Electromagnetic continuous casting (EMCC technique to be utilized with greater ease by industry.
14. A methodology for the implementation and continuous improvement of social responsibility (RS) and financial responsibility
Sanz Mendiola, Irene; Garcia Beltrán, Ángel; González Tirados, Rosa María
2012-01-01
This work sets out an innovative methodology that aims to facilitate the implementation and continuous improvement of Social Responsibility. It is a methodology that takes account of strategic-economic, social and environmental questions and allows measuring the impact of each of these aspects on the stakeholders and on each of the value areas. It can be extrapolated to all kinds of organisations regardless of their size and sector and admits scaleable models. A marked feature that s...
15. Improvements of Continuous Model for Memory-based Automatic Music Transcription
Albrecht, Š.; Šmídl, Václav
Aalborg: Eurasip, 2010, s. 487-491. ISSN 2076-1465. [European signal processing conference. Aalborg (DK), 23.07.2010-27.07.2010] R&D Projects: GA ČR GP102/08/P250 Institutional research plan: CEZ:AV0Z10750506 Keywords : music transcription * extended Kalman filter Subject RIV: BD - Theory of Information http://library.utia.cas.cz/separaty/2010/AS/smidl-improvements of continuous model for memory-based automatic music transcription.pdf
16. Iso9000 Based Advanced Quality Approach for Continuous Improvement of Manufacturing Processes
Deeb, Salah; Iung, Benoît
2006-01-01
The continuous improvement in TQM is considered as the core value by which organisation could maintain a competitive edge. Several techniques and tools are known to support this core value but most of the time these techniques are informal and without modelling the interdependence between the core value and tools. Thus, technique formalisation is one of TQM challenges for increasing efficiency of quality process implementation. In that way, the paper proposes and experiments an advanced quali...
17. Organisational Learning, Transformational Leadership and Implementation of Continuous Quality Improvement in Canadian Hospitals
Rolland LeBrasseur; Robert Whissell; Abhoy Ojha
2002-01-01
Implementing continuous quality improvement (CQI) in acute care general hospitals was investigated as an occurrence of a paradigm shift and organisational learning. Presented within a contextual framework, two case studies are reported, and are complemented by a survey of hospitals operating in Ontario, Canada. The findings support a top-down approach where the CEO exhibits transformational leadership and aligns the organisation's strategy, structure, and culture to CQI. The conflicting stake...
18. Continuous Non-Invasive Arterial Pressure Technique Improves Patient Monitoring during Interventional Endoscopy
Sylvia Siebig, Felix Rockmann, Karl Sabel, Ina Zuber-Jerger, Christine Dierkes, Tanja Brünnler, Christian E. Wrede
2009-01-01
Introduction: Close monitoring of arterial blood pressure (BP) is a central part of cardiovascular surveillance of patients at risk for hypotension. Therefore, patients undergoing diagnostic and therapeutic procedures with the use of sedating agents are monitored by discontinuous non-invasive BP measurement (NIBP). Continuous non-invasive BP monitoring based on vascular unloading technique (CNAP®, CN Systems, Graz) may improve patient safety in those settings. We investigated if this new...
19. Continuous Non-Invasive Arterial Pressure Technique Improves Patient Monitoring during Interventional Endoscopy
Siebig, Sylvia; Rockmann, Felix; Sabel, Karl; Zuber-Jerger, Ina; Dierkes, Christine; Brünnler, Tanja; Wrede, Christian E.
2009-01-01
Introduction: Close monitoring of arterial blood pressure (BP) is a central part of cardiovascular surveillance of patients at risk for hypotension. Therefore, patients undergoing diagnostic and therapeutic procedures with the use of sedating agents are monitored by discontinuous non-invasive BP measurement (NIBP). Continuous non-invasive BP monitoring based on vascular unloading technique (CNAP®, CN Systems, Graz) may improve patient safety in those settings. We investigated if this new tech...
20. A BLUEPRINT FOR EXECUTING CONTINUAL QUALITY IMPROVEMENT IN AN ENGINEERING UNDERGRADUATE PROGRAMME
School of Engineering, Taylor’s University, No. 1 Jalan Taylor’s 47500 Subang Jaya, Selangor DE, Malaysia; SIVAKUMAR SIVANESAN; MOHAMMAD HOSSEINI; FLORENCE CHOONG; CHIEN HWA CHONG; SATESH NAMASIVAYAM; MUSHTAK AL-ATABI
2013-01-01
This paper focuses on providing a template of how to practice Continual Quality Improvement (CQI) in an Engineering Undergraduate Programme. At the inception of the programme, the academic curriculum is based upon the notion of the type of graduate an institution of higher learning would like to produce. Hence, a graduate of a particular institution embodies its vision and mission. Taking this further and to ensure specificity in the type of graduate produced, Engineering Programmes provide a...
1. Hesperidin associated with continuous and interval swimming improved biochemical and oxidative biomarkers in rats
de Oliveira, David Michel; Dourado, Grace Kelly Zanotti Simoes; Cesar, Thais Borges
2013-01-01
Background Citrus flavonoids, such as hesperidin, have shown therapeutic properties that improve hyperglycemia and insulin resistance, and decrease blood serum lipids and inflammation. The current investigation studied the effects of hesperidin supplementation associated with continuous and interval swimming on the biochemical parameters (glucose, cholesterol and triglycerides), and oxidative stress markers (TBARS and DPPH) in rats. Methods The animals (n = 60) were randomly divided in six gr...
2. 41 CFR 102-193.25 - What type of records management business process improvements should my agency strive to achieve?
2010-07-01
...-193.25 What type of records management business process improvements should my agency strive to... management business process improvements should my agency strive to achieve? 102-193.25 Section 102-193.25... that needed records can be found rapidly to conduct agency business, to ensure that records...
3. IMPROVING THE READING ACHIEVEMENT OF SELECTED AT-RISK READERS: ONE SCHOOL DIVISIONâ S APPROACH
Feret, Alice J.
2001-01-01
This study describes the long-term reading achievement of a group of children identified by teachers in 1994 as low-achieving students in reading. Four research questions guided the study, and the 165 participants came from 12 elementary schools in Montgomery County, Virginia. They were selected, because they had participated in Reading Recovery in first grade and had taken the reading portion of the Stanford 9 Achievement Test in the spring of third grade. The literature review covers ...
4. Design improvements and R and D achievements for VV and In-vessel components towards ITER construction
There have been several detailed vacuum vessel (VV) design improvements, such as elimination of the inboard triangular support, separate interspace between inner and outer shells for independent leak detection of field joints and revised VV support system to gain a more comfortable margin in the structural performance. The blanket design has been updated; an inter-modular key instead of two prismatic keys and a co-axial inlet-outlet cooling connection instead of two parallel pipes. One of the most important achievements in the VV R and D has been demonstration of the necessary assembly tolerances. Further development of cutting, welding and non destructive tests (NDT) for the VV has been continued, and thermal and hydraulic tests have been performed to simulate the VV cooling conditions. With regard to the R and D for the FW/blanket and divertor, full-scale prototypical mock-ups of the FW panel, the blanket shield block and the divertor components have been successfully fabricated. These results make us confident in the validity of our design and give us possibilities of alternate fabrication methods. (author)
5. Using Student Teams-Achievement Divisions (STAD Strategy to Improve the Students’ Speaking Skill at Vocational School
Rumiarsih Rumiarsih
2014-04-01
Full Text Available The present study was conducted in order to describe how Student Teams-Achievement Divisions (STAD Strategy can improve the students’ speaking skill. The researcher used Classroom Action Research (CAR and applied it in the teaching of speaking of XII TKR 2 of SMK Negeri 1 Madiun. The finding of this research indicated that the STAD Strategy was successful in improving the students’ speaking skill. The STAD Strategy employed in this study consisted five steps, namely: (1 forming teams; (2 class presentation; (3 quiz; (4 individual improvement score; and (5 team recognition. The activities in those five steps which were don chronologically improved both in the students’ speaking achievements and the students’ participation during the teaching and learning of speaking.Key Words: speaking skill, student teams-achievement divisions (STAD strategy
6. Adhesion improvement of fibres by continuous plasma treatment at atmospheric pressure
Kusano, Y.; Andersen, Tom L.; Soerensen, B.F.; Toftegaard, H.L.; Teodoru, S. [Technical Univ. of Denmark. DTU Wind Energy, Risoe Campus, Roskilde (Denmark); Hansen, Charles M. [Hoersholm (Denmark)
2013-09-01
Carbon fibres and ultra-high-molecular-weight polyethylene (UHMWPE) fibres were continuously treated by a dielectric barrier discharge plasma at atmospheric pressure for adhesion improvement with epoxy resins. The plasma treatment improved wettability, increased the oxygen containing polar functional groups at the surface, and subsequently improved adhesion to the epoxy and fracture resistance of epoxy composites. Hansen solubility parameters (HSP), quantitatively describing physical interactions among molecules, were measured for the UHMWPE fibre surfaces. The result identifies two distinct types of surfaces in both the plasma treated and the untreated fibres. One type is typical of polyethylene polymers while the other is characteristic of the oxygenated surface at much higher values of HSP. (Author)
7. Continuous improvement process and waste reduction through a QFD tool: the case of a metallurgic plant
2013-05-01
Full Text Available This paper proposes the use of QFD for the continuous improvement of production processes and waste reduction actions. To collect the information we used the simple observation and questionnaire with closed questions applied to employees, representing 88.75% of the population that works in the production processes of an industry of metal-mechanic sector, located inRio Grandedo Sul. QFD is an effective method of quality planning, because it provides a diagnosis that underpins the definition of improvement actions aimed at combating waste. Actions were set providing improved communication between the sectors, enabling the delivery of products with specifications that meet customer requirements, on time and the right amounts, at a minimum cost and satisfaction of those involved with the company. The implementation of these actions reduces waste, minimizes the extra work, maximizes effective labor and increases profitability.
8. Kaizen - continuous improvement of high voltage products; Kaizen - kontinuierliche Verbesserung bei Hochspannungsprodukten
Schwarz, M. [ABB Calor Emag Schaltanlagen AG, Hanau-Grossauheim (Germany); Goessmann, T. [ABB Calor Emag Schaltanlagen AG, Mannheim (Germany)
1999-07-12
In the actual global competition only the company can survive who cares for the continuous improvement of all business activities. The ABB Calor Emag Schaltanlagen AG at his production site in Hanau-Grossauheim has installed a specific improvement programm called KVP what is based on the ideas of Kaizen. Aim is the improvement of processes, mainly in production, concerning quality, dates, costs and environment by activating all colleagues. (orig.) [Deutsch] Im heutigen globalen Wettbewerb kann sich nur der behaupten, der sich kontinuierlich in allen Unternehmensbereichen weiterentwickelt. Die ABB Calor Emag Schaltanlagen AG hat in ihrem Werk Hanau-Grossauheim nach den Ideen des Kaizen ein werkspezifisches Programm zur kontinuierlichen Verbesserung der Prozesse in der Fertigung eingefuehrt. Ziel ist die stetige Verbesserung von Fertigungsparametern, wie Qualitaet, Termine, Kosten und Umwelt unter Einbeziehung aller Mitarbeiter. (orig.)
9. Improvements of PKU PMECRIS for continuous hundred hours CW proton beam operation
In order to improve the source stability, a long term continuous wave (CW) proton beam experiment has been carried out with Peking University compact permanent magnet 2.45 GHz ECR ion source (PKU PMECRIS). Before such an experiment a lot of improvements and modifications were completed on the source body, the Faraday cup and the PKU ion source test bench. At the beginning of 2015, a continuous operation of PKU PMECRIS for 306 h with more than 50 mA CW beam was carried out after success of many short term tests. No plasma generator failure or high voltage breakdown was observed during that running period and the proton source reliability is near 100%. Total beam availability, which is defined as 35-keV beam-on time divided by elapsed time, was higher than 99% [S. X. Peng et al., Chin. Phys. B 24(7), 075203 (2015)]. A re-inspection was performed after another additional 100 h operation (counting time) and no obvious sign of component failure was observed. Counting the previous source testing time together, this PMECRs longevity is now demonstrated to be greater than 460 h. This paper is mainly concentrated on the improvements for this long term experiment
10. Improvements of PKU PMECRIS for continuous hundred hours CW proton beam operation
Peng, S. X.; Zhang, A. L.; Ren, H. T.; Zhang, T.; Zhang, J. F.; Xu, Y.; Guo, Z. Y.; Chen, J. E.
2016-02-01
In order to improve the source stability, a long term continuous wave (CW) proton beam experiment has been carried out with Peking University compact permanent magnet 2.45 GHz ECR ion source (PKU PMECRIS). Before such an experiment a lot of improvements and modifications were completed on the source body, the Faraday cup and the PKU ion source test bench. At the beginning of 2015, a continuous operation of PKU PMECRIS for 306 h with more than 50 mA CW beam was carried out after success of many short term tests. No plasma generator failure or high voltage breakdown was observed during that running period and the proton source reliability is near 100%. Total beam availability, which is defined as 35-keV beam-on time divided by elapsed time, was higher than 99% [S. X. Peng et al., Chin. Phys. B 24(7), 075203 (2015)]. A re-inspection was performed after another additional 100 h operation (counting time) and no obvious sign of component failure was observed. Counting the previous source testing time together, this PMECRs longevity is now demonstrated to be greater than 460 h. This paper is mainly concentrated on the improvements for this long term experiment.
11. Improvements of PKU PMECRIS for continuous hundred hours CW proton beam operation
Peng, S. X., E-mail: sxpeng@pku.edu.cn; Ren, H. T.; Zhang, T.; Zhang, J. F.; Xu, Y.; Guo, Z. Y. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); Zhang, A. L.; Chen, J. E. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)
2016-02-15
In order to improve the source stability, a long term continuous wave (CW) proton beam experiment has been carried out with Peking University compact permanent magnet 2.45 GHz ECR ion source (PKU PMECRIS). Before such an experiment a lot of improvements and modifications were completed on the source body, the Faraday cup and the PKU ion source test bench. At the beginning of 2015, a continuous operation of PKU PMECRIS for 306 h with more than 50 mA CW beam was carried out after success of many short term tests. No plasma generator failure or high voltage breakdown was observed during that running period and the proton source reliability is near 100%. Total beam availability, which is defined as 35-keV beam-on time divided by elapsed time, was higher than 99% [S. X. Peng et al., Chin. Phys. B 24(7), 075203 (2015)]. A re-inspection was performed after another additional 100 h operation (counting time) and no obvious sign of component failure was observed. Counting the previous source testing time together, this PMECRs longevity is now demonstrated to be greater than 460 h. This paper is mainly concentrated on the improvements for this long term experiment.
12. Survey of sustainability of continuous improvement systems: a comparison of two manufacturing communities in Spain and Mexico
Carmen Jaca; Manuel F. Suárez-Barraza; Elisabeth Viles-Díez; Ricardo Mateo-Dueñas; Javier Santos-García
2011-01-01
Purpose: During the last 50 years industrial companies have adopted continuous improvement systems to improve their competitiveness. However, the maintenance of improvement systems is not an easy matter. Some companies, after an initial period of one to two years, abandon the system for various reasons. This article aims to examine the level of application of Continuous Improvement Systems and the factors which support sustainability over time in two different regions.Design/methodology/...
13. Good performance in Japan is proof of continuing safety and reliability improvement practice
Nuclear power is a vital energy supply source for both security and economy for such countries as Japan whose sources of energy are dependent on imported materials. This is the very reason why Japan gives her national priority to the improvement of nuclear power safety and reliability. As of the end of 1986, total nuclear power capacity owned and operated by private utility companies in Japan amounted to 24521 MW with 32 units sharing -- 19% of the total generating capacity. Moreover, during 1986 these units scored a remarkably high capacity factor of 76.2% and shared almost 28% of the nationwide electric power production, thereby contributing to a considerable saving of imported sources of energy. This outstanding record has been achieved by the parties concerned who dedicated themselves to furthering nuclear plant safety and reliability improvement. In this connection, this paper summarizes those key factors contributing to the good nuclear power plant performance of the Kansai Electric Power Company
14. Continuous Improvement and the Safety Case for the Waste Isolation Pilot Plant Geologic Repository - 13467
The Waste Isolation Pilot Plant (WIPP) is a geologic repository 2150 feet (650 m) below the surface of the Chihuahuan desert near Carlsbad, New Mexico. WIPP permanently disposes of transuranic waste from national defense programs. Every five years, the U.S. Department of Energy (DOE) submits an application to the U.S. Environmental Protection Agency (EPA) to request regulatory-compliance re-certification of the facility for another five years. Every ten years, DOE submits an application to the New Mexico Environment Department (NMED) for the renewal of its hazardous waste disposal permit. The content of the applications made by DOE to the EPA for re-certification, and to the NMED for permit-renewal, reflect any optimization changes made to the facility, with regulatory concurrence if warranted by the nature of the change. DOE points to such changes as evidence for its having taken seriously its 'continuous improvement' operations and management philosophy. Another opportunity for continuous improvement is to look at any delta that may exist between the re-certification and re-permitting cases for system safety and the consensus advice on the nature and content of a safety case as being developed and published by the Nuclear Energy Agency's Integration Group for the Safety Case (IGSC) expert group. DOE at WIPP, with the aid of its Science Advisor and teammate, Sandia National Laboratories, is in the process of discerning what can be done, in a reasonably paced and cost-conscious manner, to continually improve the case for repository safety that is being made to the two primary regulators on a recurring basis. This paper will discuss some aspects of that delta and potential paths forward to addressing them. (authors)
15. Environmental assessment, continual improvement and adaptive management within the AREVA sustainable development framework
16. Improving the fidelity of continuous-variable quantum teleportation by tuning displacement gain
Jinming Liu(刘金明); Jian Li(李剑); Guangcan Guo(郭光灿)
2003-01-01
The fidelity of teleportation of continuous quantum variables can be improved by tuning the local displace-ment gain. We investigate the optimization of the fidelity for the teleportation of Schrodinger cat states,and of coherent states. It is found that the gain corresponding to the maximum fidelity is not equal to onefor the two input states in the case of the small squeezing degree of the entanglement resource, while unitydisplacement gain is the best choice for teleporting arbitrary quantum states in the case of large squeezing.
17. Continual summing-up, deepening the related researches and improving the interventional nursing
With the development of the medical technique in the field of clinical interventional radiology, the relevant interventional nursing team has also gradually grown and expanded. At present, there are certain differences in the development situation of interventional nursing between China and foreign countries. The experts in nursing fields in China should learn the matured experience from abroad to open up the features and superiorities of Chinese interventional nursing. Therefore, the nursing workers in China should continually to make summing-up, exert oneself to deepen the related researches and effectively improve the interventional nursing level. (authors)
18. Method of Improving the Navigation Accuracy of SINS by Continuous Rotation
YANG Yong; MIAO Ling-juan; SHEN Jun
2005-01-01
A method of improving the navigation accuracy of strapdown inertial navigation system (SINS) is studied. The particular technique discussed involves the continuous rotation of gyros and accelerometers cluster about the vertical axis of the vehicle. Then the errors of these sensors will have periodic variation corresponding to components along the body frame. Under this condition, the modulated sensor errors produce reduced system errors. Theoretical analysis based on a new coordinate system defined as sensing frame and test results are presented, and they indicate the method attenuates the navigation errors brought by the gyros' random constant drift and the accelerometer's bias and their white noise compared to the conventional method.
19. On improving the convergence rate of linear continuous-time systems subject to asymmetrically constrained control
2006-01-01
Full Text Available This paper solves the problem of controlling linear continuous-time systems subject to control signals constrained in magnitude (maybe asymmetrically. A controller design methodology is proposed, based on using an asymmetric Lyapunov function, that avoids the discontinuities in the control vector components resulting from the application of a piecewise linear control law previously proposed. The proposed method gives improved speed of convergence without discontinuities of the control vector components, respecting always the imposed asymmetric constraints. An example illustrates the approach.
20. Improving the maximum transmission distance of continuous-variable quantum key distribution using a noiseless amplifier
Blandino, Rémi; Etesse, Jean; Grangier, Philippe [Laboratoire Charles Fabry, Institut d' Optique, CNRS, Université Paris-Sud, 2 avenue Augustin Fresnel, 91127 Palaiseau Cedex (France); Leverrier, Anthony [Institute for Theoretical Physics, ETH Zurich, 8093 Zurich, Switzerland and INRIA Paris-Rocquencourt, 78153 Le Chesnay Cedex (France); Barbieri, Marco [Laboratoire Charles Fabry, Institut d' Optique, CNRS, Université Paris-Sud, 2 avenue Augustin Fresnel, 91127 Palaiseau Cedex, France and Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU (United Kingdom); Tualle-Brouri, Rosa [Laboratoire Charles Fabry, Institut d' Optique, CNRS, Université Paris-Sud, 2 avenue Augustin Fresnel, 91127 Palaiseau Cedex, France and Institut Universitaire de France, 103 boulevard St. Michel, 75005, Paris (France)
2014-12-04
We show that the maximum transmission distance of continuous-variable quantum key distribution in presence of a Gaussian noisy lossy channel can be arbitrarily increased using a heralded noiseless linear amplifier. We explicitly consider a protocol using amplitude and phase modulated coherent states with reverse reconciliation. Assuming that the secret key rate drops to zero for a line transmittance T{sub lim}, we find that a noiseless amplifier with amplitude gain g can improve this value to T{sub lim}/g{sup 2}, corresponding to an increase in distance proportional to log g. We also show that the tolerance against noise is increased.
1. Improvement of two-way continuous-variable quantum key distribution using optical amplifiers
The imperfections of a receiver's detector affect the performance of two-way continuous-variable (CV) quantum key distribution (QKD) protocols and are difficult to adjust in practical situations. We propose a method to improve the performance of two-way CV-QKD by adding a parameter-adjustable optical amplifier at the receiver. A security analysis is derived against a two-mode collective entangling cloner attack. Our simulations show that the proposed method can improve the performance of protocols as long as the inherent noise of the amplifier is lower than a critical value, defined as the tolerable amplifier noise. Furthermore, the optimal performance can approach the scenario where a perfect detector is used. (paper)
2. Valuation of environmental improvements in continuous time with mortality and morbidity effects
We present a model for valuing environmental improvements in continuous time, for individuals that can be either healthy (H) or ill (I), with constant transition between the states and constant mortality rates in each state, when environmental quality affects welfare, mortality and morbidity. The values in states H and I, VSL(H) and VSL(I), are derived from two Bellman dynamic programming equations. The individual's valuation of (small) instantaneous environmental changes, and of permanent environmental changes ('environmental investments'), are shown to depend on both VSL(H) and VSL(I), for each of the states H and I. We show that VSL(I) may exceed VSL(H), and the value of environmental improvements in the ill state may exceed those in the healthy state, in particular for short-lasting illness and when the marginal value of consumption is lower in state I than in state H. (author)
3. Improved Achievable Rates for Regularized Tomlinson-Harashima Precoding in Multiuser MIMO Downlink
Hui, Bing; Chang, KyungHi
2011-01-01
Tomlinson-Harashima precoding (THP) is considered as a prominent precoding scheme due to its capability to efficiently cancel out the known interference at the transmitter side. Therefore, the information rates achieved by THP are superior to those achieved by conventional linear precoding schemes. In this paper, a new lower bound on the achievable information rate for the regularized THP scheme under additive white Gaussian noise (AWGN) channel with multiuser interference is derived. Analytical results show that the lower bound derived in this paper is tighter than the original lower bound particularly for a low SNR range, while all lower bounds converge to 0.5xlog2(6SNR/{\\pi}e) as SNR approaches infinity.
4. Continuing Improvement in the Planetary Ephemeris with VLBA Observations of Cassini
Jones, Dayton L.; Folkner, William M.; Jacobson, Robert A.; Jacobs, Christopher S.; Romney, Jonathan D.; Dhawan, Vivek; Fomalont, Edward B.
2016-06-01
5. Safety implications of standardized continuous quality improvement programs in community pharmacy.
Boyle, Todd A; Ho, Certina; Mackinnon, Neil J; Mahaffey, Thomas; Taylor, Jeffrey M
2013-06-01
Standardized continuous quality improvement (CQI) programs combine Web-based technologies and standardized improvement processes, tools, and expectations to enable quality-related events (QREs) occurring in individual pharmacies to be shared with pharmacies in other jurisdictions. Because standardized CQI programs are still new to community pharmacy, little is known about how they impact medication safety. This research identifies key aspects of medication safety that change as a result of implementing a standardized CQI program. Fifty-three community pharmacies in Nova Scotia, Canada, adopted the SafetyNET-Rx standardized CQI program in April 2010. The Institute for Safe Medication Practices (ISMP) Canada's Medication Safety Self-Assessment (MSSA) survey was administered to these pharmacies before and 1 year into their use of the SafetyNET-Rx program. The nonparametric Wilcoxon signed-rank test was used to explore where changes in patient safety occurred as a result of SafetyNETRx use. Significant improvements occurred with quality processes and risk management, staff competence, and education, and communication of drug orders and other information. Patient education, environmental factors, and the use of devices did not show statistically significant changes. As CQI programs are designed to share learning from QREs, it is reassuring to see that the largest improvements are related to quality processes, risk management, staff competence, and education. PMID:22842505
6. Evaluating the effectiveness of a multifaceted, multilevel continuous quality improvement program in primary health care: developing a realist theory of change
Schierhout, Gill; Hains, Jennifer; Si, Damin; Kennedy, Catherine; Cox, Rhonda; Kwedza, Ru; O’Donoghue, Lynette; Fittock, Marea; Brands, Jenny; Lonergan, Katherine; Dowden, Michelle; Bailie, Ross
2013-01-01
Background Variation in effectiveness of continuous quality improvement (CQI) interventions between services is commonly reported, but with little explanation of how contextual and other factors may interact to produce this variation. Therefore, there is scant information available on which policy makers can draw to inform effective implementation in different settings. In this paper, we explore how patterns of change in delivery of services may have been achieved in a diverse range of health...
7. Coconut (Cocos nucifera L. genetic improvement in Vanuatu: overview of research achievements from 1962 to 2002
Labouisse Jean-Pierre
2004-07-01
Compared to higher-yielding hybrids, the improved VTT populations offer the advantage of being totally tolerant of coconut foliar decay and of being reproducible by farmers themselves. The merits of setting up decentralized seed gardens in the Vanuatu archipelago from improved populations at the research station, or from locally surveyed material, are discussed.
8. Continuous emission monitoring systems at power plants in China: Improving SO2 emission measurement
The Chinese Government recently mandated the installation of continuous emission monitoring systems (CEMS) at state-controlled key polluting facilities in order to provide direct, real-time, continuous measurements of sulfur dioxide (SO2) emissions. By 2010, most coal-fired power plants in China have installed and are operating SO2 CEMS. As China's Central Government strengthens the SO2 control program and implements new nitrogen oxides (NOX) and carbon dioxide (CO2) control programs, the quality of and confidence in CEMS data will become more important. This study utilizes field surveys and existing literature on Chinese CEMS to analyze their operation and management. Our study found that the Chinese government has issued a set of regulations and technical guidance documents to standardize CEMS operation, management, and supervision, and to improve the quality of CEMS data. Many power plants have followed key parts of the national CEMS rules and guidance and are periodically inspected by local environmental authorities. This study suggests several options for addressing some of the gaps and problems with the CEMS operation and supervision and thus enhancing China's CEMS program. - Highlights: → Nearly all coal power plants in China have SO2 CEMS providing direct, real-time, continuous measurements of emissions. → Government and industry have made significant progress toward a comprehensive measurement system. → We found that problems remain and CEMS operation and supervision is inconsistent. → Data from power plant CEMS often undergo limited quality assurance and analysis. → We propose some options for enhancing the CEMS network.
9. Physically Active Math and Language Lessons Improve Academic Achievement : A Cluster Randomized Controlled Trial
Mullender-Wijnsma, Marijke J.; Hartman, Esther; de Greeff, Johannes W.; Doolaard, Simone; Bosker, Roel J.; Visscher, Chris
2016-01-01
OBJECTIVES: Using physical activity in the teaching of academic lessons is a new way of learning. The aim of this study was to investigate the effects of an innovative physically active academic intervention ("Fit & Vaardig op School" [F&V]) on academic achievement of children. METHODS: Using physic
10. The Role of the High School Principal in Improving Student Learning and Achievement
Raines, Paula L.
2012-01-01
The purpose of this exploratory mixed-method correlational and interview study was to gain insights into how the school principal influences student learning and achievement by providing positive instructional leadership. Research has suggested the principal's role is highly significant in determining the quality of teaching and learning…
11. Leveraging Quality Improvement to Achieve Student Learning Assessment Success in Higher Education
Glenn, Nancy Gentry
2009-01-01
Mounting pressure for transformational change in higher education driven by technology, globalization, competition, funding shortages, and increased emphasis on accountability necessitates that universities implement reforms to demonstrate responsiveness to all stakeholders and to provide evidence of student achievement. In the face of the demand…
12. Teaching Test-Taking Strategies to Improve the Academic Achievement of Students with Mild Mental Disabilities
Kretlow, Allison G.; Lo, Ya-yu; White, Richard B.; Jordan, LuAnn
2008-01-01
This study examined the effects of teaching a test-taking strategy to 4 fourth- and fifth-grade students with mild mental disabilities on reading and math achievement. The intervention consisted of a direct and explicit instructional method using a mnemonic strategy. The participants' acquisition and application of the test-taking strategy on…
13. Using Weblog in Cooperative Learning to Improve the Achievement of History Learning
Leng, Lim Hooi; Leng, Chin Hai; Abedalaziz, Nabeel
2013-01-01
This research investigates the use of Weblog in Cooperative Learning to enhance students' learning of History. The main issues of this study were the lack of interest and low achievement scores in History learning. The objectives of this study are to explore the incorporation of Weblog in Cooperative Learning within the teaching and learning…
14. Using Self-Correction to Improve the Spelling Performance of Low-Achieving Third Graders.
Wirtz, Connie L.; And Others
1996-01-01
Comparison of two spelling strategies (traditional versus self-correction) on spelling performance of six low-achieving third-grade students found the self-correction procedure more effective than the traditional condition and also helped students maintain their ability to correctly spell previously learned words. (Author/DB)
15. Teacher Professional Development to Improve Science and Literacy Achievement of English Language Learners
Lee, Okhee; Buxton, Cory A.
2013-01-01
The school-aged population in the United States is becoming more culturally and linguistically diverse, while achievement gaps across content areas persist. At the same time, more rigorous academic demands are being placed on all students, including English language learners (ELLs). Teachers of ELLs face the double challenge of promoting English…
16. Improving grade 7 students’ achievement in initial algebra through a technology-based intervention.
Jupri, A.; Drijvers, P.H.M.; Van den Heuvel-Panhuizen, M.
2015-01-01
Digital technology plays an increasingly important role in daily life, mathematics education and algebra education in particular. To investigate the effect of a technology-rich intervention related to initial algebra on the achievement of 12–13 year old Indonesian students, we set up an experiment.
17. A Mobile Gamification Learning System for Improving the Learning Motivation and Achievements
Su, C-H.; Cheng, C-H.
2015-01-01
This paper aims to investigate how a gamified learning approach influences science learning, achievement and motivation, through a context-aware mobile learning environment, and explains the effects on motivation and student learning. A series of gamified learning activities, based on MGLS (Mobile Gamification Learning System), was developed and…
18. Using Culturally Competent Responsive Services to Improve Student Achievement and Behavior
Schellenberg, Rita; Grothaus, Tim
2011-01-01
This article illustrates standards blending, the integration of core academic and school counseling standards, as a culturally alert responsive services strategy to assist in closing the achievement gap while also enhancing employability skills and culturally salient career competencies. The responsive services intervention described in this…
19. Is There a Relationship between the Play Attention Program and Improved Student Achievement?
Webber, Jenny Ann
2011-01-01
Attention Deficit/Hyperactivity Disorder (ADHD) and its effects on student academic achievement have been researched for many years. There have been many interventions that have been used in treating ADHD that have been found successful when implemented consistently. Some of the interventions that have been researched in the past are behavior…
20. Improving Astronomy Achievement and Attitude through Astronomy Summer Project: A Design, Implementation and Assessment
Türk, Cumhur; Kalkan, Hüseyin; Iskeleli', Nazan Ocak; Kiroglu, Kasim
2016-01-01
The purpose of this study is to examine the effects of an astronomy summer project implemented in different learning activities on elementary school students, pre-service elementary teachers and in-service teachers' astronomy achievement and their attitudes to astronomy field. This study is the result of a five-day, three-stage, science school,…
1. Strategic planning as a focus for continuous improvement. A case study
Oneill, John W.; Gordon-Winkler, Lyn
1992-01-01
What do most of the successful people and organizations in our world have in common? Instead of worrying about the future, they work to create it. They have a plan, or a vision of what they want to accomplish and they focus their efforts on success. Strategic planning has been described as a disciplined, ongoing process to produce fundamental decisions and actions that shape what an organization is, what it does, and how it will respond to a changing environment. This case study discussion will evaluate the relationship between strategic planning and Total Quality Management (TQM), or continuous improvement, through the experience of the NASA Johnson Space Center in developing a strategy for the future. That experience clearly illustrates the value of strategic planning in setting the framework and establishing the overall thrust of continuous improvement initiatives. Equally significant, the fundamentals of a quality culture such as strong customer and supplier partnerships, participative involvement, open communications, and ownership were essential in overcoming the challenges inherent in the planning process. A reinforced management commitment to the quality culture was a clear, long-term benefit.
2. Continuous Improvement in Battery Testing at the NASA/JSC Energy System Test Area
Boyd, William; Cook, Joseph
2003-01-01
The Energy Systems Test Area (ESTA) at the Lyndon B. Johnson Space Center in Houston, Texas conducts development and qualification tests to fulfill Energy System Division responsibilities relevant to ASA programs and projects. EST A has historically called upon a variety of fluid, mechanical, electrical, environmental, and data system capabilities spread amongst five full-service facilities to test human and human supported spacecraft in the areas of propulsion systems, fluid systems, pyrotechnics, power generation, and power distribution and control systems. Improvements at ESTA are being made in full earnest of offering NASA project offices an option to choose a thorough test regime that is balanced with cost and schedule constraints. In order to continue testing of enabling power-related technologies utilized by the Energy System Division, an especially proactive effort has been made to increase the cost effectiveness and schedule responsiveness for battery testing. This paper describes the continuous improvement in battery testing at the Energy Systems Test Area being made through consolidation, streamlining, and standardization.
3. Waste Minimization Improvements Achieved Through Six Sigma Analysis Result In Significant Cost Savings
Improved waste minimization practices at the Department of Energy's (DOE) Idaho National Engineering and Environmental Laboratory (INEEL) are leading to a 15% reduction in the generation of hazardous and radioactive waste. Bechtel, BWXT Idaho, LLC (BBWI), the prime management and operations contractor at the INEEL, applied the Six Sigma improvement process to the INEEL Waste Minimization Program to review existing processes and define opportunities for improvement. Our Six Sigma analysis team: composed of an executive champion, process owner, a black belt and yellow belt, and technical and business team members used this statistical based process approach to analyze work processes and produced ten recommendations for improvement. Recommendations ranged from waste generator financial accountability for newly generated waste to enhanced employee recognition programs for waste minimization efforts. These improvements have now been implemented to reduce waste generation rates and are producing positive results
4. How to Evaluate the Performance of Continuous Education on the Improvement of Women’s Integrated Competence
Yong Hu
2008-01-01
Considering Chinese women’s lower education and integrated competence, governments at all levels call for improving women’s integrated quality by continuous education. However, although continuous education is an important form in China’s education system, there is no scientific measurement system to evaluate the performance of continuous education on the improvement of lower-education-degree women’s integrated competence at present. By means of comparing women’s situations before and after p...
5. Continuous heating of an air-source heat pump during defrosting and improvement of energy efficiency
Highlights: • The newly designed dual hot gas spray defrosting method was examined. • Uninterrupted heating of an air source heat pump during defrosting. • We compared newly designed dual hot gas and traditional reverse cycle defrost. • Total energy efficiency was increased by 8% compared to traditional method. - Abstract: During winter operation, an air-source heat pump extracts heat from the cold outside air and releases the heat into the living space. At certain outside air conditions, when it operates in heating mode, frost can form on the air-cooled heat exchanger, decreasing the heating performance. Conventionally, reverse-cycle defrosting (RCD) has been the common method of frost removal. But this method requires the interruption of heating during defrosting, as well as a period of time to reheat the cooled pipes of the indoor units after defrosting. In this study, a new technology called continuous heating was developed, which utilize only a hot gas bypass valve to remove the frost from the outdoor heat exchanger and thus enabling the supply of hot air to indoors without any interruption. For this, a new high temperature and low pressure gas bypass method was designed, which is differentiated from the common high pressure hot gas bypass methods by its use of low pressure. Various refrigerant mass flow distributions were examined, and the most effective defrosting mass flow was 50% in this case. Heating capacity was increased by 17% because of continuous heating, and the cumulated energy efficiency was increased by 8% compared to the traditional reverse cycle defrosting over 4 h including two defrost operations. Also, cumulated energy efficiency was increased by 27% compared to electronic heaters that supply the same heating capacity during defrosting. By this new technology, it has been proved that continuous heating and energy savings could be achieved without adopting expensive technologies
6. Enhancing turn-around-time (TAT on stroke protocol head CT reports via continuous quality improvement (CQI methodology in a busy teleradiology practice
Stephen Eigles
2015-04-01
Full Text Available Through strict adherence to continuous quality improvement (CQI methodology, over a 3 year period our teleradiology practice was able to achieve ongoing 100% compliance with our turn-around-time (TAT goal for interpretation of stroke protocol head CTs. During the 3 years prior to implementing CQI, our efforts to reduce TAT through traditional less systematic methods had been ineffective, while through the iterative CQI method of defining metrics, measuring, planning, implementation, and re-evaluation, we progressively achieved our goal of interpreting all stroke head CTs in less than 15 minutes.
7. A University Engagement Model for Achieving Technology Adoption and Performance Improvement Impacts in Healthcare, Manufacturing, and Government
McKinnis, David R.; Sloan, Mary Anne; Snow, L. David; Garimella, Suresh V.
2014-01-01
The Purdue Technical Assistance Program (TAP) offers a model of university engagement and service that is achieving technology adoption and performance improvement impacts in healthcare, manufacturing, government, and other sectors. The TAP model focuses on understanding and meeting the changing and challenging needs of those served, always…
8. Grenada, OECS Fiscal Issues : Policies to Achieve Fiscal Sustainability and Improve Efficiency and Equity of Public Expenditures
World Bank
2004-01-01
The report reviews Grenada public expenditures for the period 1995-02 and suggests policy recommendations to achieve fiscal sustainability, improve social service delivery, and reform social protection based on the economic situation of the country at the time. To restore rapid economic growth, ensure medium-term fiscal sustainability under the umbrella of the currency union and protect th...
9. Improving Learning Achievements, Motivations and Problem-Solving Skills through a Peer Assessment-Based Game Development Approach
Hwang, Gwo-Jen; Hung, Chun-Ming; Chen, Nian-Shing
2014-01-01
In this study, a peer assessment-based game development approach is proposed for improving students' learning achievements, motivations and problem-solving skills. An experiment has been conducted to evaluate the effectiveness of the proposed approach in a science course at an elementary school. A total of 167 sixth graders participated in…
10. Experimental Evaluations of Two Strategies to Improve Reading Achievement in Kenya: Enhanced Literacy Instruction and Treatment of Malaria
Jukes, Matthew; Dubeck, Margaret; Brooker, Simon; Wolf, Sharon
2012-01-01
There is less quality evidence on how malaria may affect cognitive abilities and educational achievement or on how schools can tackle the problem of malaria among school children. A randomised trial among Sri Lankan children showed that weekly malaria chemoprophylaxis with chloroquine can improve school examination scores. The Health and Literacy…
11. Top 10 Ways to Improve Science Achievement: Actions for School Principals, Assistant Principals, Department Chairs and School Improvement Consultants.
Southern Regional Education Board (SREB), 2007
2007-01-01
High Schools That Work (HSTW) Assessment data show the need to improve science education in both the middle grades and high school. Science education increases students' critical thinking and problem-solving skills. This publication is designed to help principals, other school leaders and teachers identify rigorous instruction and successfully…
12. The role of the continuous improvement tools of procesess in building relationships in supply chain
Maciej Urbaniak
2015-03-01
Full Text Available Background: The aim of this paper is to determine the importance of the quality management and environmental management systems as well as operational improvement tools (such as TPS, Six Sigma, and Lean Management in building partnerships in supply chain. Methods: This paper contains the results of survey in companies operating in Poland and an analysis of the requirements for suppliers in the implementation of the quality and environmental management systems elements as well as recommendation for them to implement process improvement tools (such as elements of the TPS, the concept of Lean Management and Six Sigma methodologies. Results: The results of the survey and the analysis of the examples show that companies that are buyers in the B2B market often define the very individualized to suppliers needs through detailed specifications defining the requirements for quality assurance, performance increases, (for example, shortening implementation cycles, efficiency (cost reduction, safety, reducing the negative impact on the environment. Conclusions: The effectiveness of the action on improving the quality of processes and products by building relationships with suppliers depends largely on the support provided to them. To achieve these objectives many companies introduce special development programs for suppliers.
13. IMPROVING LEARNER OUTCOMES IN EFL: DOES EARLY INSTRUCTION LEAD TO GREATER ACHIEVEMENT?*
Servet ÇELİK
2014-04-01
Full Text Available Language education curricula and programs worldwide have begun emphasizing foreign language instruction for learners as young as 5-6 years, particularly in English. Yet, while studies have argued for the benefits of early language instruction, the results of this trend in terms of actual achievement are not clear. For this reason, the researchers designed this study to illustrate the connection between age of onset of English as a foreign language (EFL instruction and learner achievement, examining international language curricula from countries where English is taught as a foreign language beginning at the pre-primary and primary level alongside the corresponding scores on the Test of English as a Foreign Language (TOEFL. The findings indicate that, although early onset of EFL instruction may be beneficial in many respects, it is not, in itself, a guarantee of success, and other elements, such as class size, number of hours dedicated to English instruction, and teacher qualifications, must also be considered.
14. Improving settleability and achieving biological phosphorus removal through the application of sidestream gravimetric selectors
Welling, Claire Marie
2015-01-01
This project utilizes hydrocyclones in wastewater treatment to select for heavier solids, and has been used before in multiple small-scale systems. This is the first implementation of hydrocyclones in a full-scale plant for the purpose of increased settleability, while also achieving enhanced biological phosphorus removal without the use of an anaerobic selector. Hydrocyclones receive mixed liquor tangentially and separate light solids from more dense solids through their tapered shape, in...
15. Dressed for Success: Do School Uniforms Improve Student Behavior, Attendance, and Achievement?
Scott Imberman; Elisabetta Gentile
2009-01-01
Concerns about safety in urban schools has led many school districts to require uniforms for their students. However, we know very little about what impact school uniforms have had on the educational environment. In this paper we use a unique dataset to assess how uniform adoption affects student achievement and behavior in a large urban school district in the southwest. Since each school in the district could decide independently about whether or not to adopt uniforms, we are able to use var...
16. IMPROVING LEARNER OUTCOMES IN EFL: DOES EARLY INSTRUCTION LEAD TO GREATER ACHIEVEMENT?*
ÇELİK, SERVET; Karaca, Bilal
2014-01-01
Language education curricula and programs worldwide have begun emphasizing foreign language instruction for learners as young as 5-6 years, particularly in English. Yet, while studies have argued for the benefits of early language instruction, the results of this trend in terms of actual achievement are not clear. For this reason, the researchers designed this study to illustrate the connection between age of onset of English as a foreign language (EFL) instruction and learner...
17. Evaluation of organizational self-assessment tools and methodologies to measure continuous process improvement for the Naval Aviation Enterprise
Kaehler. Theodore J.
2006-01-01
The Naval Aviation Enterprise (NAE) has created a program called AIRSpeed to deliver the efficiency gains of continuous process improvement (CPI). NAE leadership seeks a self-assessment tool to measure how well AIRSpeed has been implemented, including possible areas for improvement. This thesis studies the origins of continuous process improvement, the value of assessment, and current assessment methodologies. Key concepts are cited for the use of organizational assessment tools. The objectiv...
18. Continuing education program evaluation for course improvement, participant effect and utilization in clinical practice.
Faulk, L G
1984-04-01
19. The Nearly Continuous Improvement of Discharge Characteristics and Edge Stability with Increasing Lithium Coatings in NSTX
Full text: The understanding of regimes with: 1. High pressure at the top of the H-mode pedestal. 2. Devoid of large ELMs is important for scenario optimization of ITER and future devices. Lithium wall coatings have been shown to both improve energy confinement and eliminate ELMs in NSTX. Here, we present analysis of variable pre-discharge lithium evaporation from multiple experiments, for more insight into the pedestal expansion and ELM suppression physics. First, a nearly continuous improvement of a number of discharge characteristics, e.g., reduced recycling, ELM frequency, and edge electron transport, with increasing pre-discharge lithium evaporation has been identified. These correlations ran contrary to initial expectations that the beneficial effects would saturate at much lower evaporation amounts than used in experiments. Profile and stability analysis clarified the mechanism responsible for ELM avoidance and the role of lithium: lithium coatings reduce recycling and core fueling; thus the density and its gradient near the separatrix are reduced. The temperature gradient near the separatrix is unaffected; hence the pressure gradient and bootstrap current near the separatrix are reduced, leading to stabilization of kink/peeling modes thought to be responsible for the NSTX ELMs. Thus, the enhanced edge stability with lithium coatings is correlated with the reduction of the pressure and its gradient near the separatrix. The key ingredient for ELM avoidance is control of the particle channel independent of the thermal channel at the edge: the density profile is continuously manipulated via the amount of lithium evaporation and resulting recycling control, leading to reduced neutral fueling. The surprising and beneficial facet of the NSTX data, however, is the continued growth of the edge transport barrier width in these circumstances, leading to 100 % higher plasma pressure at the approximate top of the ne profile barrier with high pre-discharge evaporation
20. A Gaussian-like immersed-boundary kernel with three continuous derivatives and improved translational invariance
Bao, Yuanxun; Kaye, Jason; Peskin, Charles S.
2016-07-01
The immersed boundary (IB) method is a general mathematical framework for studying problems involving fluid-structure interactions in which an elastic structure is immersed in a viscous incompressible fluid. In the IB formulation, the fluid described by Eulerian variables is coupled with the immersed structure described by Lagrangian variables via the use of the Dirac delta function. From a numerical standpoint, the Lagrangian force spreading and the Eulerian velocity interpolation are carried out by a regularized, compactly supported discrete delta function, which is assumed to be a tensor product of a single-variable immersed-boundary kernel. IB kernels are derived from a set of postulates designed to achieve approximate grid translational invariance, interpolation accuracy and computational efficiency. In this note, we present a new 6-point immersed-boundary kernel that is C3 and yields a substantially improved translational invariance compared to other common IB kernels.
1. In praise of conscious awareness: a new framework for the investigation of 'continuous improvement' in expert athletes
John eToner
2014-07-01
Full Text Available A key postulate of traditional theories of motor skill learning (e.g., Fitts and Posner, 1967; Shiffrin and Schneider, 1977 is that expert performance is largely automatic in nature and tends to deteriorate when the performer ‘reinvests’ in, or attempts to exert conscious control over, proceduralized movements (Masters and Maxwell, 2008. This postulate is challenged, however, by recent empirical evidence (e.g., Nyberg, in press; Geeves et al., in press which shows that conscious cognitive activity plays a key role in facilitating further improvement amongst expert sports performers and musicians – people who have already achieved elite status (Toner and Moran, in press. This evidence suggests that expert performers in motor domains (e.g., sport, music can strategically deploy conscious attention to alternate between different modes of bodily awareness (reflective and pre-reflective during performance. Extrapolating from this phenomenon, the current paper considers how a novel theoretical approach (adapted from Sutton, McIlwain, Christensen, and Geeves, 2011 could help researchers to elucidate some of the cognitive mechanisms mediating continuous improvement amongst expert performers.
2. In praise of conscious awareness: a new framework for the investigation of "continuous improvement" in expert athletes.
Toner, John; Moran, Aidan
2014-01-01
A key postulate of traditional theories of motor skill-learning (e.g., Fitts and Posner, 1967; Shiffrin and Schneider, 1977) is that expert performance is largely automatic in nature and tends to deteriorate when the performer "reinvests" in, or attempts to exert conscious control over, proceduralized movements (Masters and Maxwell, 2008). This postulate is challenged, however, by recent empirical evidence (e.g., Nyberg, in press; Geeves et al., 2014) which shows that conscious cognitive activity plays a key role in facilitating further improvement amongst expert sports performers and musicians - people who have already achieved elite status (Toner and Moran, in press). This evidence suggests that expert performers in motor domains (e.g., sport, music) can strategically deploy conscious attention to alternate between different modes of bodily awareness (reflective and pre-reflective) during performance. Extrapolating from this phenomenon, the current paper considers how a novel theoretical approach (adapted from Sutton et al., 2011) could help researchers to elucidate some of the cognitive mechanisms mediating continuous improvement amongst expert performers. PMID:25076931
3. A combined continuous and interval aerobic training improves metabolic syndrome risk factors in men
Sari-Sarraf V
2015-05-01
Full Text Available Vahid Sari-Sarraf,1 Akbar Aliasgarzadeh,2 Mohammad-Mahdi Naderali,3 Hamid Esmaeili,1 Ebrahim K Naderali4 1Department of Exercise Physiology, Faculty of Physical Education and Sport Sciences, University of Tabriz, 2Bone Research Centre, Endocrine Unit, Department of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran; 3The School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, 4Faculty of Science, Liverpool Hope University, Liverpool, UK Abstract: Individuals with metabolic syndrome have significantly higher risk of cardiovascular disease and type 2 diabetes leading to premature death mortality. Metabolic syndrome has a complex etiology; thus, it may require a combined and multi-targeted aerobic exercise regimen to improve risk factors associated with it. Therefore, the aim of this study was to evaluate the effect of combined continuous and interval aerobic training on patients with metabolic syndrome. Thirty adult male with metabolic syndrome (54±8 years were randomly divided into two groups: test training group (TTG; n=15 and control group (CG; n=15. Subjects in TTG performed combined continuous and interval aerobic training using a motorized treadmill three times per week for 16 weeks. Subjects in CG were advised to continue with their normal activities of life. Twenty-two men completed the study (eleven men in each group. At the end of the study, in TTG, there were significant (for all, P<0.05 reductions in total body weight (-3.2%, waist circumference (-3.43 cm, blood pressure (up to -12.7 mmHg, and plasma insulin, glucose, and triacylglyceride levels. Moreover, there were significant (for all, P<0.05 increases VO2max (-15.3% and isometric strength of thigh muscle (28.1% and high-density lipoprotein in TTG. None of the above indices were changed in CG at the end of 16-week study period. Our study suggests that adoption of a 16-week combined continuous and interval aerobic training regimen in men
4. Achieving k-anonymity Using Improved Greedy Heuristics for Very Large Relational Databases
Korra Sathya Babu
2013-04-01
Full Text Available Advances in data storage, data collection and inference techniques have enabled the creation of huge databases of personal information. Dissemination of information from such databases - even if formally anonymised, creates a serious threat to individual privacy through statistical disclosure. One of the key methods developed to limit statistical disclosure risk is k-anonymity. Several methods have been proposed to enforce k-anonymity notably Samarati's algorithm and Sweeney's Datafly, which both adhere to full domain generalisation. Such methods require a trade off between computing time and information loss. This paper describes an improved greedy heuristic for enforcing k-anonymity with full domain generalisation. The improved greedy algorithm was compared with the original methods. Metrics like information loss, computing time and level of generalisation were deployed for comparison. Results show that the improved greedy algorithm maintains a better balance between computing time and information loss.
5. The continuous improvement system of nuclear power plant of Laguna Verde; El sistema de mejora continua de la central nucleoelectrica Laguna Verde
Rivera C, A. [Comision Federal de Electricidad, Central Nucleoelectrica Laguna Verde, Km. 42.5 Cardel-Nautla, Veracruz (Mexico)], e-mail: arr99999@cfe.gob.mx
2009-10-15
This paper describes the continuous improvement system of nuclear power plant of Laguna Verde and the achievements in implementing the same and additionally two study cases are presents. In February 2009 is noteworthy because the World Association of Nuclear Operators we identified as a learning organization, qualification which shows that the continuous improvement system has matured, and this system will expose as I get to learn to capitalize on our own experiences and external experiences diffused by the nuclear industry. In 2007 the management of nuclear power plants integrates its improvement systems and calls it continuous improvement system and is presented in the same extensive report that won the National Quality Award. This system is made up of 5 subsystems operating individually and are also related 1) human performance; 2) referential comparison or benchmarking; 3) self-assessment; 4) corrective action and 5) external operating experience. Five subsystems that plan, generate, capture, manage, communicate and protect the knowledge generated during the processes execution of nuclear power plant of Laguna Verde, as well as from external sources. The target set in 2007 was to increase the intellectual capital to always give response to meeting the security requirements, but creating a higher value to quality, customer, environment protection and society. In brief each of them, highlighting the objective, expectations management, implementation and some benefits. At the end they will describe two study cases selected to illustrate these cases as the organization learns by their continuous improvement system. (Author)
6. Researching achievement and inclusion to improve the educational experiences and outcomes of all learners
Lani FLORIAN
2011-11-01
Full Text Available This paper considers some of the key issues that must be taken into account when conducting research on inclusive education in an era of standards based reform. It challenges the widely held assumption that high levels of educational inclusion are incompatible with high levels of academic achievement in schools and presents the Framework for Participation, a research tool developed by the authors, which supports practitioners (and other researchers who wish to examine the development of inclusive practice in their own schools.
7. Achieving best practice tariff may not reflect improved survival after hip fracture treatment
Khan SK
2014-12-01
Full Text Available Sameer K Khan,1 Mark DF Shirley,2 Clare Glennie,1 Paul V Fearon,1 David J Deehan1 1The Newcastle upon Tyne Hospitals NHS Foundation Trust, 2School of Biology, Newcastle University, Newcastle upon Tyne, UK Objective: The best practice tariff (BPT incentivizes hospitals in the England and Wales National Health Service to provide multiprofessional care to patients with hip fractures. The initial six targets included: 1 admission under consultant-led joint orthopedic–geriatric care, 2 multidisciplinary assessment protocol on admission, 3 surgery within 36 hours, 4 geriatrician review within 72 hours, 5 multiprofessional rehabilitation, and 6 assessment for falls and bone protection. We aimed to examine the relationship between BPT achievement and important patient outcomes and whether the BPT could predict these independently of other validated predictors.Materials and methods: A retrospective review was conducted on 516 patient episodes. Four outcomes were defined: 1 30-day mortality, 2 365-day mortality, 3 postoperative length of stay on trauma ward (LOS-T, and 4 total post-operative hospital LOS (LOS-H. Patient episodes were grouped as follows: 1 group 1, pre-BPT, 2 group 2, BPT achievers, 3 group 3, BPT fails. These were compared for mortality (χ2 test and for LOS (Kruskal–Wallis test. Event analysis was done for groups 2 and 3 using generalized linear modeling, with age, sex, American Society of Anesthesiologists grade, hemoglobin, albumin, creatinine, and BPT achievement evaluated as predictors.Results: The three groups did not differ significantly in baseline characteristics or outcomes. In the event analysis, the risk of 30-day mortality was related only to abnormal creatinine (P=0.025; mortality at 365 days was related significantly to low albumin (P=0.023 and weakly to abnormal creatinine (P=0.089. The risks of both increased LOS-T and LOS-H were related to age only (P=0.052, P<0.001, respectively.Conclusion: Achieving BPT does not
8. A Knowledge Tree Model and Its Application for Continuous Management Improvement
Lu, Yun; Bao, Zhen-Qiang; Zhao, Yu-Qin; Wang, Yan; Wang, Gui-Jun
This chapter analyzes the relationship of organizational knowledge and brings forward that organizational knowledge consists of three layers: core knowledge, structural knowledge, and implicit knowledge. According to the principle of knowledge maps, a dynamic management model of organizational knowledge based on knowledge tree is introduced and the definition of the value of knowledge node is given so that the quantitative management on knowledge is realized, which lays a foundation for performance evaluation of knowledge management. We also carefully study the application of knowledge tree in service quality management of hospital organizations and management innovation process and give the example of cooperation in endoscopic surgery to establish a knowledge tree about operational cooperation degree, which states the principle of organizational knowledge management and the knowledge innovation process of continuous management improvement.
9. THEORY OF REASONED ACTION FOR CONTINUOUS IMPROVEMENT CAPABILITIES: A BEHAVIORAL APPROACH
Janaina Siegler
2012-09-01
Full Text Available The importance of interaction between Operations Management (OM and Human Behavior has been recently re-addressed. This paper introduced the Reasoned Action Theory suggested by Froehle and Roth (2004 to analyze Operational Capabilities exploring the suitability of this model in the context of OM. It also seeks to discuss the behavioral aspects of operational capabilities from the perspective of organizational routines. This theory was operationalized using Fishbein and Ajzen (F/A behavioral model and a multi-case strategy was employed to analyze the Continuous Improvement (CI capability. The results posit that the model explains partially the CI behavior in an operational context and some contingency variables might influence the general relationsamong the variables involved in the F/A model. Thus intention might not be the determinant variable of behavior in this context.
10. Integrating the development of continuous improvement andinnovation capabilities into engineering education
Jørgensen, Frances; Kofoed, Lise B.
2007-01-01
, followed by an account of how the students designed and implemented solutions to self-identified problems within their educational program using the principles of CI, and how these learning activities facilitated the development of basic innovation capabilities. The paper concludes with insights regarding......In this paper, a study is presented in which engineering students at a Danish university developed Continuous Improvement (CI) and innovation capabilities through action research and experientiallearning methods. The paper begins with a brief overview of the literature on CI and innovation...... how such an innovative design of teaching methods based on learning-by-doing may not only support the development of CI and innovation in engineering students, which is increasingly demanded by industry, but also represent a way in which to enhance sustainability and innovation of the education itself....
11. A Marketing approach on how continuous processes improvement can contribute to hotel business Organic Growth
Ioana-Simona IVASCIUC
2015-12-01
Full Text Available Generating sustainable growth and profits is like finding a unicorn for most managers. Organic growth should be considered as an alternative for long-term growth in the hotel business. Designing the service process to deliver what customers expect from the hotel offer is a crucial component of encounter marketing. Hotels need to embrace the changes and ensure that their internal processes are aligned not just to current trends, but also to the expected future changes. Keeping up with global changes and trends of any kind, evaluating their impact on your business, continuous improving of the services using PDCA cycle, Six Sigma or Lean principles, are the keys to long-term organic growth.
12. The new health-care quality: value, outcomes, and continuous improvement.
O'Connor, S J; Lanning, J A
1991-01-01
No longer convinced that their viewpoint on quality is the only one, different stakeholders in the health-care arena are sharing perspectives to piece together the quality picture. Although still preoccupied with the cost of health care, purchasers are concerned about value--efficiency, appropriateness, and effectiveness--as well as price. Faced with evidence of medically unnecessary procedures and unexamined medical theory, practitioners are searching for appropriateness guidelines, useful outcome measures, and methods to elicit informed patient preferences about elective surgeries. Underlying this search for reliable indicators of quality--now expanded to include patient satisfaction--is a new interest in the Japanese notion of "Kaizen" or continuous quality improvement. The end product of this ferment may determine whether good medicine drives out the bad--or vice versa. PMID:10118887
13. Continuous quality improvement: a shared governance model that maximizes agent-specific knowledge.
Burkoski, Vanessa; Yoon, Jennifer
2013-01-01
Motivate, Innovate, Celebrate: an innovative shared governance model through the establishment of continuous quality improvement (CQI) councils was implemented across the London Health Sciences Centre (LHSC). The model leverages agent-specific knowledge at the point of care and provides a structure aimed at building human resources capacity and sustaining enhancements to quality and safe care delivery. Interprofessional and cross-functional teams work through the CQI councils to identify, formulate, execute and evaluate CQI initiatives. In addition to a structure that facilitates collaboration, accountability and ownership, a corporate CQI Steering Committee provides the forum for scaling up and spreading this model. Point-of-care staff, clinical management and educators were trained in LEAN methodology and patient experience-based design to ensure sufficient knowledge and resources to support the implementation. PMID:24860947
14. Effects of Direct Teaching Using Creative Memorization Strategies To Improve Math Achievement.
Bielsker, Staci; Napoli, Lori; Sandino, Melissa; Waishwell, Lesa
This report describes a program for enhancing direct teaching using creative memorization strategies in order to improve retention and quick retrieval of math facts. The targeted population consisted of first and second grade students in two separate districts in middle class communities. Analysis of probable cause data revealed that students were…
15. Increasing Student Achievement and Improving Self-Esteem through a Community Building Intervention
Lupo, Concetta M.
2012-01-01
This study focused on improving students' self-esteem through community building at an elementary school in a low socioeconomic community where over 55% of the students live below the poverty line. Orefield and Yun state in their 1999 article, "Resegregation of America's schools," "school level poverty is related to many…
16. India - Improving Household Food and Nutrition Security : Achievements and the Challenges Ahead, Volume 1. Main Report
World Bank
2001-01-01
This report focuses on the performance of, and future challenges for, the Government of India's primary "direct food and nutrition safety nets" or food-based transfer programs designed to alleviate short-term food and nutrition insecurity and improve caring behavior within households. This study focuses on the public food distribution system, the government's buffer stocking operations for...
17. India - Improving Household Food and Nutrition Security : Achievements and the Challenges Ahead, Volume 2. Annexes
World Bank
2001-01-01
This report focuses on the performance of, and future challenges for, the Government of India's primary "direct food and nutrition safety nets" or food-based transfer programs designed to alleviate short-term food and nutrition insecurity and improve caring behavior within households. This study focuses on the public food distribution system, the government's buffer stocking operations for...
18. Effects of Simulated Interventions to Improve School Entry Academic Skills on Socioeconomic Inequalities in Educational Achievement
Chittleborough, Catherine R.; Mittinty, Murthy N.; Lawlor, Debbie A.; Lynch, John W.
2014-01-01
Randomized controlled trial evidence shows that interventions before age 5 can improve skills necessary for educational success; the effect of these interventions on socioeconomic inequalities is unknown. Using trial effect estimates, and marginal structural models with data from the Avon Longitudinal Study of Parents and Children (n = 11,764,…
19. An Improved Real-Coded Population-Based Extremal Optimization Method for Continuous Unconstrained Optimization Problems
Guo-Qiang Zeng
2014-01-01
Full Text Available As a novel evolutionary optimization method, extremal optimization (EO has been successfully applied to a variety of combinatorial optimization problems. However, the applications of EO in continuous optimization problems are relatively rare. This paper proposes an improved real-coded population-based EO method (IRPEO for continuous unconstrained optimization problems. The key operations of IRPEO include generation of real-coded random initial population, evaluation of individual and population fitness, selection of bad elements according to power-law probability distribution, generation of new population based on uniform random mutation, and updating the population by accepting the new population unconditionally. The experimental results on 10 benchmark test functions with the dimension N=30 have shown that IRPEO is competitive or even better than the recently reported various genetic algorithm (GA versions with different mutation operations in terms of simplicity, effectiveness, and efficiency. Furthermore, the superiority of IRPEO to other evolutionary algorithms such as original population-based EO, particle swarm optimization (PSO, and the hybrid PSO-EO is also demonstrated by the experimental results on some benchmark functions.
20. Improving University Ranking to Achieve University Competitiveness by Management Information System
Dachyar, M.; Dewi, F.
2015-05-01
One way to increase university competitiveness is through information system management. A literature review was done to find information system factors that affect university performance in Quacquarelli Symonds (QS) University Ranking: Asia evaluation. Information system factors were then eliminated using Delphi method through consensus of 7 experts. Result from Delphi method was used as measured variables in PLS-SEM. Estimation with PLS-SEM method through 72 respondents shows that the latent variable academic reputation and citation per paper have significant correlation to university competitiveness. In University of Indonesia (UI) the priority to increase university competitiveness as follow: (i) network building in international conference, (ii) availability of research data to public, (iii) international conference information, (iv) information on achievements and accreditations of each major, (v) ease of employment for alumni.
1. Coconut (Cocos nucifera L.) genetic improvement in Vanuatu: overview of research achievements from 1962 to 2002
Labouisse Jean-Pierre; Sileye Tiata; Morin Jean-Paul; Hamelin Chantal; Baudouin Luc; Bourdeix Roland; Rouzière André
2004-01-01
From 1962 to 2002, at the Saraoutou research station on the island of Santo in Vanuatu, genetic improvement work was undertaken to increase the productivity of coconut plantations, which, through copra exports, were the country’s main wealth in the last century. Beginning with two Vanuatu Tall (VTT) populations collected near the station, four mass selection cycles by open pollination or intercrossing have resulted in Elite Vanuatu Tall populations intended for distribution to farmers. The st...
2. Coconut (Cocos nucifera L.) genetic improvement in Vanuatu: Overview of research achievements from 1962 to 2002.
Labouisse Jean-Pierre; Sileye Tiata; Morin Jean-Paul; Hamelin Chantal; Baudouin Luc; Bourdeix Roland; Rouzière André
2005-01-01
From 1962 to 2002, at the Saraoutou research station on the island of Santo in Vanuatu, a hybrid creation programme was implemented to improve the productive potential of coconut cultivars. The first stage was to create a collection by introducing around thirty exotic varieties. All those varieties and most of the 60 hybrids created proved to be susceptible to coconut foliar decay, a viral disease transmitted by Myndus taffini and endemic in Vanuatu. Only the Vanuatu Tall populations and two ...
3. Continuously improving safety of nuclear installations: An approach to be reinforced after the Fukushima accident
Repussard, Jacques; Schwarz, Michel
2012-05-01
After the Three Mile Island accident in 1979 and the Chernobyl accident in 1986, the Fukushima accident shows that the probability of a core meltdown accident in an LWR (Light Water Reactor) has been largely underestimated. The consequences of such an accident are unacceptable: except in the case of TMI2 (Three Mile Island 2) large areas around the damaged plants are contaminated for decades and populations have to be relocated for long periods. This article presents the French approach which consists in improving continuously the safety of the Nuclear Power Plants (NPP) on the basis of lessons learned from operating experience and from the progress in R&D (Research and Development). It details the key role played by IRSN (Institut de radioprotection et de sûreté nucléaire), the French TSO (Technical and scientific Safety Organization), and shows how the Fukushima accident contributes to this approach in improving NPP robustness. It concludes on the necessity to keep on networking TSOs, to share knowledge as well as R&D resources, with the ultimate goal of enhancing and harmonizing nuclear safety worldwide.
4. An improved cross entropy algorithm for steelmaking-continuous casting production scheduling with complicated technological routes
王桂荣; 李歧强; 王鲁浩
2015-01-01
In order to increase productivity and reduce energy consumption of steelmaking-continuous casting (SCC) production process, especially with complicated technological routes, the cross entropy (CE) method was adopted to optimize the SCC production scheduling (SCCPS) problem. Based on the CE method, a matrix encoding scheme was proposed and a backward decoding method was used to generate a reasonable schedule. To describe the distribution of the solution space, a probability distribution model was built and used to generate individuals. In addition, the probability updating mechanism of the probability distribution model was proposed which helps to find the optimal individual gradually. Because of the poor stability and premature convergence of the standard cross entropy (SCE) algorithm, the improved cross entropy (ICE) algorithm was proposed with the following improvements: individual generation mechanism combined with heuristic rules, retention mechanism of the optimal individual, local search mechanism and dynamic parameters of the algorithm. Simulation experiments validate that the CE method is effective in solving the SCCPS problem with complicated technological routes and the ICE algorithm proposed has superior performance to the SCE algorithm and the genetic algorithm (GA).
5. Continued improvement of cardiovascular mortality in Hungary - impact of increased cardio-metabolic prescriptions
Jozan Peter
2010-07-01
Full Text Available Abstract Background During the last 35 years the poor ranking of Hungary on the list of life expectancy at birth among European countries, has not changed. In 1970 our lag behind the leading European countries was the smallest. The gap was growing between 1970 and 1993 but from 1994 onwards the life expectancy at birth in Hungary has increased continuously and somewhat faster than in other European countries. The aim of this study was to analyze the association between decreasing cardiovascular mortality rates, as a main cause of death and the increase in cardio-metabolic prescriptions and possible changes in lifestyle behavior. Methods Analyses were conducted on national data concerning cardiovascular mortality and the number of cardio-metabolic drug prescription per capita. The association between yearly rates of cardiovascular events and changes in antihypertensive, antilipidemic and antidiabetic prescription rates was analyzed. The changes in other cardiovascular risk factors, like lifestyle were also considered. Results We observed a remarkable decline of mortality due to stroke and acute myocardial infarction (AMI. The fall was significantly associated with all prescription rates. The proportion of each treatment type responsible for suppression of specific mortality rates is different. All treatment types comparably improved stroke mortality, while antilipidemic therapy improved AMI outcome. Conclusions These results emphasize the importance of a comprehensive strategy that maximizes the population coverage of effective treatments. Hungary appears to be at the beginning of the fourth stage of epidemiologic transition, i.e. it has entered the stage of delayed chronic noninfectious diseases.
6. Continuous Non-Invasive Arterial Pressure Technique Improves Patient Monitoring during Interventional Endoscopy
Sylvia Siebig, Felix Rockmann, Karl Sabel, Ina Zuber-Jerger, Christine Dierkes, Tanja Brünnler, Christian E. Wrede
2009-01-01
Full Text Available Introduction: Close monitoring of arterial blood pressure (BP is a central part of cardiovascular surveillance of patients at risk for hypotension. Therefore, patients undergoing diagnostic and therapeutic procedures with the use of sedating agents are monitored by discontinuous non-invasive BP measurement (NIBP. Continuous non-invasive BP monitoring based on vascular unloading technique (CNAP®, CN Systems, Graz may improve patient safety in those settings. We investigated if this new technique improved monitoring of patients undergoing interventional endoscopy. Methods: 40 patients undergoing interventional endoscopy between April and December 2007 were prospectively studied with CNAP® in addition to standard monitoring (NIBP, ECG and oxygen saturation. All monitoring values were extracted from the surveillance network at one-second intervals, and clinical parameters were documented. The variance of CNAP® values were calculated for every interval between two NIBP measurements. Results: 2660 minutes of monitoring were recorded (mean 60.1±34.4 min/patient. All patients were analgosedated with midazolam and pethidine, and 24/40 had propofol infusion (mean 90.9±70.3 mg. The mean arterial pressure for CNAP® was 102.4±21.2 mmHg and 106.8±24.8 mmHg for NIBP. Based on the first NIBP value in an interval between two NIBP measurements, BP values determined by CNAP® showed a maximum increase of 30.8±21.7% and a maximum decrease of 22.4±28.3% (mean of all intervals. Discussion: Conventional intermittent blood pressure monitoring of patients receiving sedating agents failed to detect fast changes in BP. The new technique CNAP® improved the detection of rapid BP changes, and may contribute to a better patient safety for those undergoing interventional procedures.
7. Coconut (Cocos nucifera L. genetic improvement in Vanuatu: Overview of research achievements from 1962 to 2002.
Labouisse Jean-Pierre
2005-03-01
Full Text Available From 1962 to 2002, at the Saraoutou research station on the island of Santo in Vanuatu, a hybrid creation programme was implemented to improve the productive potential of coconut cultivars. The first stage was to create a collection by introducing around thirty exotic varieties. All those varieties and most of the 60 hybrids created proved to be susceptible to coconut foliar decay, a viral disease transmitted by Myndus taffini and endemic in Vanuatu. Only the Vanuatu Tall populations and two hybrids (Vanuatu Red Dwarf × Vanuatu Tall and Vanuatu Tall × Rennell Island Tall displayed tolerance enabling their distribution to farmers. The author indicates the origin of the parents and the production characteristics of these two hybrids. The Vanuatu Red Dwarf × Vanuatu Tall hybrid expresses good hybrid vigour with a production potential ranging from 2.5 to 3.4 tons per hectare per year. However, it does have several defects: slow germination and a highly irregular final germinated nut rate, susceptibility to cyclones when young, premature nut fall sometimes seen on young palms, and a mediocre copra content (between 135 and 160 g. The Vanuatu Tall × Rennell Island Tall hybrid stands out through its early start to bearing (4 years, its vigour and its good adaptation to cyclones. The copra content of its nuts (between 210 and 245 g is better than that of the Vanuatu Tall, making copra preparation easier. Its production ranges from 2.5 to 3 tons per hectare per year, which is around 30% better than the improved Vanuatu Tall (Elite Vanuatu Tall. However, dissemination of this hybrid, which can only be produced in centralized seed gardens, is limited by the cost of production and of transport throughout the archipelago. Only large-scale Elite Vanuatu Tall production in decentralized seed gardens would enable a significant improvement in coconut productivity in Vanuatu.
8. How far should a new leader reinterpret a school’s values to achieve improvement?
McGrath, A.J.
2011-01-01
This dissertation considers the approach of a head teacher to the task of leading a new school, and provides a heuristic study of the question of whether, in order to be true to self, the head should reinterpret the stated values of the school to attune with his own. It examines the problem of reconciling the values of the leader and the school while leading a process of school improvement and serving the school and wider religious community which the school represents. The particular context...
9. Incomplete reporting of enhanced recovery elements and its impact on achieving quality improvement
Day, R W; Fielder, S; Calhoun, J;
2015-01-01
explanation for early mobilization was satisfactory in 41 (82 per cent) of the 50 publications, although only 14 (30 per cent) of 47 listing the variable reported compliance. Other ER elements had similar rates of explanation and compliance. The most frequently analysed outcome measures were morbidity (49, 98...... per cent), length of stay (47, 94 per cent) and mortality (45, 90 per cent). CONCLUSION: The current standard of reporting is frequently incomplete. To transfer knowledge and facilitate implementation of pathways that demonstrate improvements in perioperative care and recovery, a consistent structured...
10. Radiation safety infrastructure in developing countries: a proactive approach for integrated and continuous improvement
11. Radiation safety infrastructure in developing countries: a proactive approach for integrated and continuous improvement
12. Mentoring At-risk Youth: Improving Academic Achievement in Middle School Students
Kellie C. Johnson
2010-01-01
Full Text Available Research supports the implementation of mentoring programs as potentially successful approaches to meeting the needs of at-risk students. This study examined a mentoring program entitled: LISTEN (Linking Individual Students To Educational Needs. The LISTEN mentoring program was a district-sponsored, school-based program in which at-risk, middle school students were identified by the school system and mentors were recruited specifically to assist these students with school performance or related issues. Mentors, in this study, were classroom teachers, school counselors, administrators, custodians, librarians, teaching assistants, retired teachers, and cafeteria employees. Archival data from the 2003–04 and 2004–05 academic years were analyzed. A statistically significant difference was found for all three of the study’s criterion variables (GPAs, discipline referrals, and attendance records between those measured in the 2003–04 academic year (pre-intervention and those measured in the 2004–05 academic year (post-intervention. Forty-nine of the fifty-four LISTEN participants experienced academic achievement gains in all three areas of the study.
13. TSO assistance towards the improvement of nuclear safety in Lithuania: achievements and perspectives
Butcher, P. [Serco Assurance, Winfrith, Dorchester, Dorset (United Kingdom); Bystedt, P. [Swedish International Project, Nuclear Safety (SIP), Stockholm (Sweden); Chouha [CEA Fontenay-aux-Roses, 92 (France). Inst. de Protection et de Surete Nucleaire; Uspuras, E. [Lithuanian Energy Institute (LEI), Kaunas (Lithuania); Weber, J.P. [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Garching (Germany); Zilys, K. [State Nuclear Power Safety Inspectorate (VATESI), Vilnius (Lithuania)
2001-07-01
This paper explores the improvements that have taken place at INPP (Ignalina nuclear power plant) in both the engineering and operational aspects of nuclear safety, discussing as example some areas where there has been a large involvement of international experts. The development of the Lithuanian Nuclear Regulatory Authority VATESI, and also the technical support organisations for both the regulator and the NPP are discussed. In each of these sections the paper describes some of the successes and also the areas where there have been some problems. Many of the problems have been resolved but challenges remain for the future. The paper only deals with the assistance towards enhancing the safety of the NPP up to the time of its closure. Regulation of decommissioning is an important area for the future and is receiving urgent attention and active planning at the present time. (authors)
14. TSO assistance towards the improvement of nuclear safety in Lithuania: achievements and perspectives
This paper explores the improvements that have taken place at INPP (Ignalina nuclear power plant) in both the engineering and operational aspects of nuclear safety, discussing as example some areas where there has been a large involvement of international experts. The development of the Lithuanian Nuclear Regulatory Authority VATESI, and also the technical support organisations for both the regulator and the NPP are discussed. In each of these sections the paper describes some of the successes and also the areas where there have been some problems. Many of the problems have been resolved but challenges remain for the future. The paper only deals with the assistance towards enhancing the safety of the NPP up to the time of its closure. Regulation of decommissioning is an important area for the future and is receiving urgent attention and active planning at the present time. (authors)
15. Organisational learning: A tool for continuous improvement of the organization; Aprendizaje Organizativo: una herramienta para la mejora continua de la organizacion
Santos, J. L.; Esteban, M. J.
2013-09-01
We are used to hear a success company in today's world is not possible unless a continuous improvement is developed. How can we be successful in the nuclear plant? We have to achieve safety for workers, people and environment in the first step, and for the second step availability and reliability for systems and components to avoid failure of components that could reduce availability. The aim is to search for new measures to reach this way. One of the improvements implemented in the plants to improve continuously was mainly Operating Experience activities, which was based in event analysis in the plants, causes identification, and to implement corrective actions. For External Operating Experience the aim was to learn from others to avoid occurrence of events in our plants. This was the lessons learned from Three Mile Island event. This was the learning process implemented so far, to get a continuous improvement. So far, the developed capabilities for process improvement follow the Operating Experience process that could be considered classical and will be revitalized nowadays. (Author)
16. Functioning of the university focused on the quality and continuous improvement
M. Dudek-Burlikowska
2009-12-01
Full Text Available Purpose: A new approach to the functioning of quality management system at university focused on the quality has been presented.Design/methodology/approach: The profits resulting from possessing of Quality Management System certificate in higher education has been proposed.Findings: At the present time the educational organizations should implement Quality Management Systems, and next they should try to find a possibility of estimation of this System, and the same acting according to Deming’s principles introduce philosophy of total quality management.Research limitations/implications: Generally definitions of quality educational has been described. Quality of university should implement to integrate aspects based on the quality criterion which will allow the entire organizational system of university to achieve the optimum level of the quality, of the high effectiveness and the innovation, and proquality action should include the entire organization.Practical implications: The possibility of implementing Method of Averaging Quality Groups of Rating as a factor of improving of university functioning has been shown.Originality/value: Implementing the Method of Averaging Quality Groups of Rating has been a new approach for estimating quality of university. Design the quality pattern of Criterial Model of the Evaluation of Quality University and calculate the index of quality of scientific organization become the kind of monitoring the entire university oriented on the quality.
17. Continuous quality improvement in daily clinical practice: a proof of concept study.
Jonathan A Lorch
Full Text Available Continuous Quality Improvement (CQI is an iterative process of: planning to improve a product or process, plan implementation, analyzing and comparing results against those expected, and corrective action on differences between actual and expected results. It is little used in clinical medicine. Anemia, a complex problem in End Stage Renal Disease patients, served to test the ability of an unique electronic medical record (EMR optimized for daily care to empower CQI in practice. We used data collected during daily care, stored in the EMR, and organized to display temporal relationships between clinical, laboratory, and therapeutic events. Our aims were optimal hemoglobin with minimum epoetin, and maintaining stable hemoglobin and epoetin. The study was done on 250 patients treated by maintenance hemodialysis (HD, receiving epoetin prior to February 1, 2010 and followed to July 31, 2011. Repleting iron, ensuring iron sufficiency, slow epoetin reduction, and decision support tools enabling data display over long periods in patient-centered reports were key elements. Epoetin dose, adjusted 6-8 weekly, was based on current clinical conditions and past responses. Hemoglobin increased by months 1-2; epoetin decreased from month 4. By months 16-18, epoetin had decreased 42% to 9,720 units/week while hemoglobin increased 8% to 123.6 g/L. Hemoglobin and epoetin were stable from month 7 onward. New epoetin orders decreased 83%. Transferrin saturation increased after the study start. Individual patient hemoglobin variation decreased by 23%, range by 27%. Mortality, 11.78 per 100 patient years, was 42% less than United States dialysis patient mortality. Allowable epoetin charges decreased by $15.33 per treatment and were$22.88 less than current Medicare allowance. The study validates the hypothesis that an EMR optimized for daily patient care can empower CQI in clinical medicine and serve to monitor medical care quality and cost.
18. The Influence of a Continuing Medical Education Campaign on New Strategies to Improve Appropriate Use of Antibiotics
Brenda A. Bucklin
2015-01-01
Full Text Available Introduction. Widespread use of antibiotics has led to drug-resistant bacteria and reports of drug-resistant infections. A continuing medical education (CME campaign was used to improve antibiotic use among primary care providers. Methods. The Office of CME and Professional Development at the University of Colorado School of Medicine produces a semiannual, week-long course for primary care providers. A 2-year multifaceted CME campaign consisted of course content on antibiotic use, a practice audit, and two surveys to measure perceptions of the problem of antibiotic overuse, potential barriers to achieving appropriate use, and strategies to overcome barriers. Results. The overall response rate in the 2nd part of the campaign was 68.4%. Sixty-six percent of respondents had implemented at least one strategy to reduce antibiotic overuse. The rate was significantly higher among those who had attended previous reviews (81.0% compared with those who had attended neither (54%, p=0.0002. However, there was no “dose effect” on the rate of implementing a new strategy. Conclusions. Overuse of antibiotic therapy has important public health implications. Results suggest that mixed interactive and didactic CME program was effective in increasing awareness of antibiotic overuse and strategies for reducing antibiotic administration.
19. Improved dichotomous search frequency offset estimator for burst-mode continuous phase modulation
Zhai, Wen-Chao; Li, Zan; Si, Jiang-Bo; Bai, Jun
2015-11-01
A data-aided technique for carrier frequency offset estimation with continuous phase modulation (CPM) in burst-mode transmission is presented. The proposed technique first exploits a special pilot sequence, or training sequence, to form a sinusoidal waveform. Then, an improved dichotomous search frequency offset estimator is introduced to determine the frequency offset using the sinusoid. Theoretical analysis and simulation results indicate that our estimator is noteworthy in the following aspects. First, the estimator can operate independently of timing recovery. Second, it has relatively low outlier, i.e., the minimum signal-to-noise ratio (SNR) required to guarantee estimation accuracy. Finally, the most important property is that our estimator is complexity-reduced compared to the existing dichotomous search methods: it eliminates the need for fast Fourier transform (FFT) and modulation removal, and exhibits faster convergence rate without accuracy degradation. Project supported by the National Natural Science Foundation of China (Grant No. 61301179), the Doctorial Programs Foundation of the Ministry of Education, China (Grant No. 20110203110011), and the Programme of Introducing Talents of Discipline to Universities, China (Grant No. B08038).
20. MANUFACTURING AND CONTINUOUS IMPROVEMENT AREAS USING PARTIAL LEAST SQUARE PATH MODELING WITH MULTIPLE REGRESSION COMPARISON
Carlos Monge Perry
2014-07-01
Full Text Available Structural equation modeling (SEM has traditionally been deployed in areas of marketing, consumer satisfaction and preferences, human behavior, and recently in strategic planning. These areas are considered their niches; however, there is a remarkable tendency in empirical research studies that indicate a more diversified use of the technique. This paper shows the application of structural equation modeling using partial least square (PLS-SEM, in areas of manufacturing, quality, continuous improvement, operational efficiency, and environmental responsibility in Mexico’s medium and large manufacturing plants, while using a small sample (n = 40. The results obtained from the PLS-SEM model application mentioned, are highly positive, relevant, and statistically significant. Also shown in this paper, for purposes of validity, reliability, and statistical power confirmation of PLS-SEM, is a comparative analysis against multiple regression showing very similar results to those obtained by PLS-SEM. This fact validates the use of PLS-SEM in areas of untraditional scientific research, and suggests and invites the use of the technique in diversified fields of the scientific research
1. A BLUEPRINT FOR EXECUTING CONTINUAL QUALITY IMPROVEMENT IN AN ENGINEERING UNDERGRADUATE PROGRAMME
School of Engineering, Taylor’s University, No. 1 Jalan Taylor’s 47500 Subang Jaya, Selangor DE, Malaysia
2013-04-01
Full Text Available This paper focuses on providing a template of how to practice Continual Quality Improvement (CQI in an Engineering Undergraduate Programme. At the inception of the programme, the academic curriculum is based upon the notion of the type of graduate an institution of higher learning would like to produce. Hence, a graduate of a particular institution embodies its vision and mission. Taking this further and to ensure specificity in the type of graduate produced, Engineering Programmes provide a set of Programme Educational Objectives (PEOs which are derived from the vision and mission. From these PEOs, the Programme Outcomes (POs are crafted, followed by the Learning Outcomes (LOs at the module level – and hence the appropriate curriculum is decided upon. Once the programme is in full implementation, there exists a need to monitor and control the PEOs, POs and LOs to ensure that the programme progresses and evolves. Herein lies the need to practice CQI at all three levels. The following paper will provide an emphasis of how CQI, implemented correctly can result in enhancing the overall student learning experience.
2. The potential of Arachis pintoi biomass to improve quality of soil continuously used for cassava cropping
N. Muddarisna
2014-01-01
Full Text Available A field experiment that was aimed to elucidate the effects of application of Arachis pintoi biomass and animal dung on quality of soil continuously used for cassava cropping was conducted at Jatikerto Village, Kromengan District of Malang Regency. Eight treatments tested were 100% NPK inorganic fertilizer, 100 kg N Arachis pintoi/ha, (3 100 kg N chicken dung/ ha, 100 kg N cow dung /ha, 100 kg N goat dung /ha, 100 kg N Arachis pintoi + chicken dung /ha, 100 kg N Arachis pintoi + cow dung /ha, and 100 kg N Arachis pintoi + goat dung /ha. Monitoring quality of top soil (0-20 cm was carried out at planting time and 3 months after planting. Soil samples were collected and analyzed for chemical and physical properties. Yield of cassava was measured at 6 months after planting. Results of this study showed that application of organic fertilizer in forms of green manure (Arachis pintoi biomass, and animal dung significantly improved physical and chemical properties of soil. Application of 50% NPK combined with organic manures did not significantly gave different tuber yield with that of 100% NPK.
3. Randomized Trial of the Availability, Responsiveness and Continuity (ARC) Organizational Intervention for Improving Youth Outcomes in Community Mental Health Programs
Glisson, Charles; Hemmelgarn, Anthony; Green, Philip; Williams, Nathaniel J.
2013-01-01
Objectives: The primary objective of the study was to assess whether the Availability, Responsiveness and Continuity (ARC) organizational intervention improved youth outcomes in community based mental health programs. The second objective was to assess whether programs with more improved organizational social contexts following the 18-month ARC…
4. Survey of sustainability of continuous improvement systems: a comparison of two manufacturing communities in Spain and Mexico
Carmen Jaca
2011-04-01
Full Text Available Purpose: During the last 50 years industrial companies have adopted continuous improvement systems to improve their competitiveness. However, the maintenance of improvement systems is not an easy matter. Some companies, after an initial period of one to two years, abandon the system for various reasons. This article aims to examine the level of application of Continuous Improvement Systems and the factors which support sustainability over time in two different regions.Design/methodology/approach: In order to obtain a comparative result between two different regions, a survey was conducted in two industrial zones—one in the north of Spain and another in Mexico—that are important industrial clusters these countries. The study was conducted through the analysis of survey data. Specifically, the survey was directed at large industrial enterprises who had participated in activities supported by local foundations for the promotion of quality and improvement.Findings and Originality/value: We suggest the following three keys for sustainable improvement: greater involvement of task forces in the improvement program, a PDCA improvement cycle for improvement and a clear purpose for continuous improvement, integration of the continuous improvement system in the organization, and the establishment of indicators associated with the system.Research limitations/implications: The comparative study focused on only two industrial zones in Spain and Mexico. In that sense, the findings of the research are limited to the Basque zone and geographical zone of Toluca-Lerma.Practical implications: Some of the companies have started to apply some continuous improvement techniques in a sustainability way. Therefore, these findings could be very useful for general and operation managers that are involved in continuous improvement systems in industrial companies in Spain and Mexico.Social implications: As a consequence, slow and small transformations in certain
5. Evaluation and capacity building to improve precollege science and mathematics achievement in the US: 10 CFR, Part 605
1992-01-01
The National Center for Improving Science Education has undertaken activities to achieve evaluation goals for DOE's Precollege programs: develop means to determine program quality; develop means for determining the contribution of DOE precollege programs to both teacher enhancement and student achievement; provide evaluation designs and instruments and reports of program quality and impact; and strengthen both DOE's and the Labs' capacity to do both short- and long-term planning as well as deliver effective programs and evaluation. Appendices include evaluation/technical assistance report, profiling teacher research participation and teacher development programs, teacher surveys, impact assessment design, and teacher research participation programs anecdotes for 8 labs.
6. Assessing the Impact of Continuous Quality Improvement on Clinical Practice: What It Will Take to Accelerate Progress
Shortell, Stephen M.; Bennett, Charles L.; Byck, Gayle R.
1998-01-01
The literature on continuous quality improvement (CQI) has produced some evidence, based on nonrandomized studies, that its clinical application can improve outcomes of care while reducing costs. Its effectiveness is enhanced by a nucleus of physician involvement, individual practitioner feedback, and a supportive organizational culture. The few randomized studies, however, suggest no impact of CQI on clinical outcomes and no evidence to date of organization-wide improvement in clinical perfo...
7. Hybrid Continuous Wavelet Based Controulet Transform Method for DICOM Image Compression and Improved SPHIT Coding
C.S. Manikandababu
2015-03-01
Full Text Available The widely used standard for medical image storage and transmission is named as Digital Imaging and Communication in Medicine (DICOM. In every field of medicine including diagnosis, treatment, and research, medical images that are obtained as the outputs of the techniques such as the Computerized Tomography (CT, magnetic resonance (MR, digital subtraction angiography (DSA and Ultrasonography (US are saved as DICOM format. Network sharing of these larger sized radiology images require large bandwidth. Hence before transferring, compression of such larger image files is necessary for easy and faster communication even with lower bandwidth. Huge amount of data either in multidimensional or multiresolution form is been created as a result of medical information. This makes the following steps like retrieval, efficient storage, management, and transmission of these data a complex process. This complexity could be reduced by compressing the medical data without any loss. Many methods have been proposed so far for compression of the large DICOM images, however with some limitations. Thus, specific methods to overcome the limitations like reducing the noise of MSE error signal and improving the PSNR value results in the medical images are to be proposed for the study. One such method is referred as Hybrid Weibull Probability Density Function based Continuous Wavelet based controulet transform (WPDF-CWBCT that helps for compression of medical images without any data loss and also for improving the PSNR and reducing the MSE of the signal. The directional filter banks are being applied by initializing using the wavelet transform such that the image coding scheme is maintained based on the proposed transform. WPDF-CWBCT also uses a new set partitioning in hierarchical trees by employing a sorting method (SPIHT algorithm that provided an embedded code. In this method, the diagnostics capabilities are not compromised to ensure the better performance of image
8. Fortifier and Cream Improve Fat Delivery in Continuous Enteral Infant Feeding of Breast Milk
Mika Tabata
2015-02-01
Full Text Available Premature and high-risk infants require accurate delivery of nutrients to promote appropriate growth. Continuous enteral feeding methods may result in significant fat and micronutrient loss. This study evaluated fat loss in enteral nutrition using current strategies for providing high-risk infants fortified human milk (HM. The fat content of HM was measured by IR analyzer in a simulated feeding system using the Kangaroo epumpTM and the MedFusionTM 2010 pump. Comparisons in fat loss were made between HM, HM supplemented with donor HM-derived fortifier Prolacta + H2MFTM (H2MF, and HM supplemented with H2MF and donor HM-derived cream ProlactCRTM (cream. When using the Kangaroo epumpTM, the addition of H2MF and cream to HM increased fat delivery efficiency from 75.0% ± 1.2% to 83.7% ± 1.0% (p < 0.0001. When using the MedFusionTM 2010 pump, the addition of H2MF to HM increased fat delivery efficiency from 83.2% ± 2.8% to 88.8% ± 0.8% (p < 0.05, and the addition of H2MF and cream increased fat delivery efficiency to 92.0% ± 0.3% (p < 0.01. The addition of H2MF and cream to HM provides both the benefits of bioactive elements from mother’s milk and increased fat delivery, making the addition of H2MF and cream an appropriate method to improve infant weight gain.
9. Closing the social-class achievement gap: a difference-education intervention improves first-generation students' academic performance and all students' college transition.
Stephens, Nicole M; Hamedani, MarYam G; Destin, Mesmin
2014-04-01
College students who do not have parents with 4-year degrees (first-generation students) earn lower grades and encounter more obstacles to success than do students who have at least one parent with a 4-year degree (continuing-generation students). In the study reported here, we tested a novel intervention designed to reduce this social-class achievement gap with a randomized controlled trial (N = 168). Using senior college students' real-life stories, we conducted a difference-education intervention with incoming students about how their diverse backgrounds can shape what they experience in college. Compared with a standard intervention that provided similar stories of college adjustment without highlighting students' different backgrounds, the difference-education intervention eliminated the social-class achievement gap by increasing first-generation students' tendency to seek out college resources (e.g., meeting with professors) and, in turn, improving their end-of-year grade point averages. The difference-education intervention also improved the college transition for all students on numerous psychosocial outcomes (e.g., mental health and engagement). PMID:24553359
10. Continuous improvement programs as processes for organizational learning: A case study of a company in the food products industry.
André Luiz Fischer
2010-05-01
Full Text Available This article intends to show the relationships between quality practices and the process of organizational learning. When we look at the literature about programs of continuous improvement, we see that theoreticians consider that the process of organizational learning is a superior stage in the quality culture adopted by companies. To investigate this possibility, we put together a series of indicators taken from classic authors who have written about organizational learning. Adopting a multiple methodology, we applied these indicators to two plants belonging to the Nestlé food product company, which have introduced continuous improvement programs over the last two years.
11. Predicting core losses and efficiency of SRM in continuous current mode of operation using improved analytical technique
Parsapour, Amir, E-mail: amirparsapour@gmail.com [Department of Electrical Engineering, University of Isfahan, Isfahan (Iran, Islamic Republic of); Dehkordi, Behzad Mirzaeian, E-mail: mirzaeian@eng.ui.ac.ir [Department of Electrical Engineering, University of Isfahan, Isfahan (Iran, Islamic Republic of); Moallem, Mehdi, E-mail: moallem@cc.iut.ac.ir [Department of Electrical Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)
2015-03-15
In applications in which the high torque per ampere at low speed and rated power at high speed are required, the continuous current method is the best solution. However, there is no report on calculating the core loss of SRM in continuous current mode of operation. Efficiency and iron loss calculation which are complex tasks in case of conventional mode of operation is even more involved in continuous current mode of operation. In this paper, the Switched Reluctance Motor (SRM) is modeled using finite element method and core loss and copper loss of SRM in discontinuous and continuous current modes of operation are calculated using improved analytical techniques to include the minor loop losses in continuous current mode of operation. Motor efficiency versus speed in both operation modes is obtained and compared. - Highlights: • Continuous current method for Switched Reluctance Motor (SRM) is explained. • An improved analytical technique is presented for SRM core loss calculation. • SRM losses in discontinuous and continuous current operation modes are presented. • Effect of mutual inductances on SRM performance is investigated.
12. The continuous field view of representing forest geographically: from cartographic representation towards improved management planning
Mozgeris, Gintautas
2009-01-01
Enhanced vizualization leads to better forest management solutions. This paper discusses the application of numerical remote sensing and geographic information systems to forest inventory. Natural phenomena usually exhibit both continuous and discrete behaviour. Discrete models have been used since the inception of aerial photography, long before the introduction of mathematical statistics, computers or remote sensing but today, forest attributes can also be described as continuous surfaces. ...
13. Improvement of two-way continuous variable quantum cryptography by using additional noise
The performance of quantum key distribution such as one-way continuous variable protocols, can be increased by adding some noise on the reference side of error correction in the error-correction phase. For this reason, we here study this possibility in the case of two-way continuous variable system. Finally, the numerical results show that the using of additional noise gives two-way schemes better security performance in terms of secret key rates and resistance to channel excess noise.
14. High-dose continuous oxacillin infusion results in achievement of pharmacokinetics targets in critically ill patients with deep sternal wound infections following cardiac surgery.
Nesseler, Nicolas; Verdier, Marie-Clémence; Launey, Yoann; Malherbe, Alexandre; Dermu, Marine; Piau, Caroline; Flécher, Erwan; Tribut, Olivier; Mallédant, Yannick; Seguin, Philippe
2014-09-01
Knowledge regarding antimicrobial therapy strategies in deep sternal wound infections (DSWI) following cardiac surgery is limited. Therefore, we aimed to determine the steady-state plasma and mediastinal concentrations of oxacillin administered by continuous infusion in critically ill patients with DSWI and to compare these concentrations with the susceptibility of staphylococci recovered. A continuous infusion of oxacillin (150 to 200 mg/kg of body weight/24 h) was administered after a loading dose (50 mg/kg). Plasma and mediastinal concentrations of total and unbound oxacillin were determined 4 h after the loading dose (H4) and then at day 1 (H24) and day 2 (H48). Twelve patients were included. Nine patients exhibited bacteremia, 5 were in septic shock, 8 were positive for Staphylococcus aureus, and 4 were positive for coagulase-negative staphylococci. The median MIC (first to third interquartile range) was 0.25 (0.24 to 0.41) mg/liter. Median plasma concentrations of total and unbound oxacillin at H4, H24, and H48 were, respectively, 64.4 (41.4 to 78.5) and 20.4 (12.4 to 30.4) mg/liter, 56.9 (31.4 to 80.6) and 21.7 (6.5 to 27.3) mg/liter, and 57.5 (32.2 to 85.1) and 20 (14.3 to 35.7) mg/liter. The median mediastinal concentrations of total and unbound oxacillin at H4, H24, and H48 were, respectively, 2.3 (0.7 to 25.9) and 0.9 (oxacillin delivered by continuous infusion is a valuable strategy to achieve our pharmacokinetic target (4× MIC) at the site of action at H24. But concerns remain in cases of higher MICs, emphasizing the need for clinicians to obtain the MICs for the bacteria and to monitor oxacillin concentrations, especially the unbound forms, at the target site. PMID:24982092
15. Life Improvement of Pot Hardware in Continuous Hot Dipping Processes Final Report
Xingbo Liu
2006-01-18
The process of continuous galvanizing of rolled sheet steel includes immersion into a bath of molten zinc/aluminum alloy. The steel strip is dipped in the molten bath through a series of driving motors and rollers which control the speed and tension of the strip, with the ability to modify both the amount of coating applied to the steel as well as the thickness and width of the sheet being galvanized. There are three rolls used to guide the steel strip through the molten metal bath. The rolls that operate in the molten Zn/Al are subject to a severely corrosive environment and require frequent changing. The performance of this equipment, the metallic hardware submerged in the molten Zn/Al bath, is the focus of this research. The primary objective of this research is to extend the performance life of the metallic hardware components of molten Zn/Al pot hardware by an order of magnitude. Typical galvanizing operations experience downtimes on the order of every two weeks to change the metallic hardware submerged in the molten metal bath. This is an expensive process for industry which takes upwards of 3 days for a complete turn around to resume normal operation. Each roll bridle consists of a sink, stabilizer, and corrector roll with accompanying bearing components. The cost of the bridle rig with all components is as much as $25,000 dollars just for materials. These inefficiencies are of concern to the steel coating companies and serve as a potential market for many materials suppliers. This research effort served as a bridge between the market potential and industry need to provide an objective analytical and mechanistic approach to the problem of wear and corrosion of molten metal bath hardware in a continuous sheet galvanizing line. The approach of the investigators was to provide a means of testing and analysis that was both expeditious and cost effective. The consortium of researchers from West Virginia University and Oak Ridge National Laboratory developed 16. Public Relations in Catholic Secondary Schools: Nearly 40 Years of Continuous Improvement James, John T. 2004-01-01 This article traces the phenomenal improvement in public relations efforts over the past 40 years made by Catholic secondary schools. The improvements were brought about by crises, a theological paradigm shift, professional lay involvement, a growing awareness and appreciation of public relations, competition, and increasing financial need. The… 17. School Improvement. Keys to School Boardsmanship. A Program of Continuing Education for School Board Members. Washington State School Directors Association, Olympia. The materials in this manual are designed to help workshop leaders prepare for and present a workshop for school board members on identifying and practicing policies that effectively foster improved instruction. In confirming school boards' commitment to school improvement, this workshop also points out the boards' roles in governance, the… 18. Improving Electrical Engineering Education at the American University of Sharjah through Continuous Assessment Al-Nashash, Hasan; Khaliq, Abdul; Qaddoumi, Nasser; Al-Assaf, Yousef; Assaleh, Khaled; Dhaouadi, Rached; El-Tarhuni, Mohamed 2009-01-01 The electrical engineering (ELE) program at the American University of Sharjah (AUS) is designed to fulfill the ABET criteria. Several assessment tools are used to qualitatively and quantitatively measure the level of achievement of the program's educational objectives and outcomes. These tools include alumni, employer, and graduate advisor… 19. Internships That Make a Difference: Two Campuses Continuous Internship Improvement Experience McCarthy, Richard; Petrausch, Robert 2008-01-01 Internships have been used by many academic programs to augment the student's educational experience. We discuss two internship programs that have been continuously refined in recent years to provide the students with a structured learning experience. We present a model for enriching student experiences by integrating internship experiences with… 20. Direct Measurement and Evaluation for Mechanical Engineering Programme Outcomes: Impact on Continuous Improvement Tahir, Mohd Faizal Mat; Khamis, Nor Kamaliana; Wahid, Zaliha; Ihsan, Ahmad Kamal Ariffin Mohd; Ghani, Jaharah Ab; Sabri, Mohd Anas Mohd; Sajuri, Zainuddin; Abdullah, Shahrum; Sulong, Abu Bakar 2013-01-01 Universiti Kebangsaan Malaysia (UKM) is a research university that continuously undergoes an audit and accreditation process for the management of its courses. The Faculty of Engineering and the Built Environment (FKAB) is subjected to such processes, one of them is the auditing conducted by the Engineering Accreditation Council (EAC), which gives… 1. Lean management: innovative tools for engaging teams in continuous quality improvement. Perreault, Lucille; Vaillancourt, Lise; Filion, Catherine; Hadj, Camélia 2014-01-01 Lean management has proven to be a sustainable method to ensure a high level of patient care through innovation and teamwork. It involves a set of six tools that allow for visual management shared among team members. The team focuses their efforts on the improvement of organizational indicators in a standardized and engaging way, resulting in the sustainability of improvements. This article outlines the program's rollout at Montfort Hospital (l'Hôpital Montfort). In only a few months, two pilot units accomplished close to 50 improvements each. In addition, the organizational employee satisfaction questionnaire showed very positive results. PMID:25191803 2. La motivación de logro mejora el rendimiento académico (Achievement Motivation Improves Academic Performance Jose Miguel Garcia-Ramirez 2016-01-01 Full Text Available A través de los proyectos de innovación docente las universidades mejoran y consolidan la calidad de la educación que ofrecen, tomando la creatividad y visibilidad como claves de la motivación por competencias y logro. Método: La investigación se realiza durante el curso académico 2013-14, a través del proyecto de innovación docente “ReiDoCrea” de la Universidad de Granada. Los participantes (N=62, M=22.7, SD=6.6, estudiantes de la Facultad de Ciencias del Trabajo, se adscribieron voluntariamente al Grupo Experimental (n=30 o al Grupo Control (n=32. El grupo experimental participó en el proyecto, mientras que el grupo control no participó; los instrumentos utilizados fueron dos pruebas objetivas (pre y post del programa de evaluación académica. Resultados: El análisis estadístico muestra que existen diferencias significativas entre los resultados obtenidos por el Grupo Experimental (M=83.6, SE=1.259, t(60=3.748, p<.05, d=.95 r=.43 y el Grupo Control (M=77.25, SE=1.14. Conclusiones: En la innovación docente, la motivación por competencias y de logro es clave para desarrollar el pensamiento creativo y mejorar el rendimiento académico. Abstract: Through teaching innovation projects universities improve and consolidate the quality of education they offer, taking creativity and visibility as the key to competence and achievement motivation. Method: The research study was conducted during the academic year 2013-14, through the teaching innovation project "ReiDoCrea" of the University of Granada. The participants (N=62, M=22.7, SD=6.6, students of the Faculty of Labour, voluntarily joined the Experimental Group (n=30 or the Control Group (n=32. The experimental group participated in the project, while the Control Group did not participate; the instruments used were two objective tests (pre and post, part of the academic program evaluation. Results: The statistical analysis shows that there are significant differences between the 3. La motivación de logro mejora el rendimiento académico (Achievement Motivation Improves Academic Performance Jose Miguel Garcia-Ramirez 2016-01-01 Full Text Available A través de los proyectos de innovación docente las universidades mejoran y consolidan la calidad de la educación que ofrecen, tomando la creatividad y visibilidad como claves de la motivación por competencias y logro. Método: La investigación se realiza durante el curso académico 2013-14, a través del proyecto de innovación docente “ReiDoCrea” de la Universidad de Granada. Los participantes (N=62, M=22.7, SD=6.6, estudiantes de la Facultad de Ciencias del Trabajo, se adscribieron voluntariamente al Grupo Experimental (n=30 o al Grupo Control (n=32. El grupo experimental participó en el proyecto, mientras que el grupo control no participó; los instrumentos utilizados fueron dos pruebas objetivas (pre y post del programa de evaluación académica. Resultados: El análisis estadístico muestra que existen diferencias significativas entre los resultados obtenidos por el Grupo Experimental (M=83.6, SE=1.259, t(60=3.748, p<.05, d=.95, r=.43 y el Grupo Control (M=77.25, SE=1.14. Conclusiones: En la innovación docente, la motivación por competencias y de logro es clave para desarrollar el pensamiento creativo y mejorar el rendimiento académico. Abstract: Through teaching innovation projects universities improve and consolidate the quality of education they offer, taking creativity and visibility as the key to competence and achievement motivation. Method: The research study was conducted during the academic year 2013-14, through the teaching innovation project "ReiDoCrea" of the University of Granada. The participants (N=62, M=22.7, SD=6.6, students of the Faculty of Labour, voluntarily joined the Experimental Group (n=30 or the Control Group (n=32. The experimental group participated in the project, while the Control Group did not participate; the instruments used were two objective tests (pre and post, part of the academic program evaluation. Results: The statistical analysis shows that there are significant differences between the 4. Mechanism and Application of a New Guard Rail for Improving the Stability of Small Radius Curve Tracks with Continuous Welded Rails Mao Jian-Hong 2014-01-01 Full Text Available This study studied an effect of a new guard rail on the stability of curve tracks with CWR and revealed a mechanism of the new guard rail for improving the stability of small radius curve tracks with CWR and also analyze the degree of the new guard rail for enlarging the pave range of small radius curve tracks with CWR. In order to achieve these, an improved load-deformation method for calculating the stability of tracks with Continuous Welded Rails (CWR is suggested and verified. The results indicate that the improved load-deformation method not only has the same accuracy as the improved unified formula in specification, but also has the same clear and simple characteristics as the original load-deformation method. The mechanism of the new guard rail for improving the stability of small radius curve tracks with CWR is that the CWR stability can be greatly improved by increasing the stiffness of the track framework under conditions of maintaining the same cross-sectional area of the rails. The CWR with the new guard rail can allow the minimum laying radius from 300 m down to 230 m, i.e., the current specification limit can be relaxed 23.3%. If combined with the roadbed strengthening measures, the new guard rail can allow the minimum laying radius from 300 m down to 140 m, i.e., the current specification limit can be further relaxed 53.3%. 5. Repeated Self- and Peer-Review Leads to Continuous Improvement in Child Interviewing Performance Stolzenberg, Stacia N.; Lyon, Thomas D. 2016-01-01 The present study examined whether a training model that focuses on consistent exposure to protocol procedure, self-evaluation, and intensive peer-review sessions could improve interviewers’ ability to adhere to best practices. Law students (N = 19) interviewed 5- to 10-year-old children on a weekly basis as part of a semester-long forensic child interviewing class. They transcribed their interviews, and participated in one-hour self and peer-reviews. The proportion of each question type was calculated (option-posing, Wh-, and open-invitations) within each interview for each interviewer. Across ten weeks of interviews, interviewers consistently improved their performance, decreasing the proportion of option-posing questions by 31% and increasing the proportion of open-invitations by 47%. All interviewers improved. The present study suggests that with consistent self-evaluation and peer-review, forensic interviewers can incrementally improve their performance. 6. Innovations in Pedriatic Cradiopulmonary Bypass: a continuous process of quality improvement Golab, Hanna 2011-01-01 textabstractCardiopulmonary bypass (CPB) is defined as a technique that temporarily replaces the function of the heart and lungs, maintaining an adequate blood circulation and oxygen content of the body during surgery of the heart and great vessels. The current practice of cardiopulmonary bypass was achieved through the efforts of a numbers of individuals who believed that artificial cardiopulmonary support could replace the body’s own circulatory and respiratory systems. Collaborative effort... 7. Transformational Approach To School Leadership: Contribution To Continued Improvement Of Education Anca Nedelcu 2013-01-01 Over the last decades, an impressive number of conceptual models in the field of educational leadership have emerged; contingency or trait theories, situational, instructional, shared or distributed school leadership approaches, all tried to demonstrate their specific impact on school development and students achievement. The present paper is focused on exploring one of the foremost models, subject of systematic inquiry and controversial debates developed in relation with school or in nonscho... 8. Slovenska »mala« inovativnost: nenehno izboljševanje ali trajna stagnacija? = Slovenian Employee Suggestion Systems: A Continuous Improvement Or a Continuous Stagnation? Peter Fatur 2010-12-01 Full Text Available The operations management theory emphasizes the management ofincremental innovations as one of the cornerstones for continuous improvementof a firm’s operational efficiency. Also in Slovenia, the companiesfollow the foreign practices in this field as well as developingtheir own solutions. Unfortunately, the introduction of employee suggestionsystems very often turns out to be a failure. The paper aimsto analyze the incremental innovation management systems, in particularthe employee suggestion systems, on a sample of Sloveniancompanies from the automotive and fabricated metal products industry.Based on the key output indices, two groups of companies are definedwith a different ability to introduce innovations. The main differencesin the organization of the employee suggestions managementbetween the two groups are presented. As such, the research resultsmay contribute to an improvement and further growth of these systemsin Slovenian companies. 9. A method of improving the performance of continuous data protection system Huo, Daoan; Cao, Qiang; Xie, Changsheng; Yang, Jing 2009-08-01 Data is the core resource of the information system, so that data corruption is one of the key problems which are on top of the radar screen of most information system administrators. Continuous Data Protection (CDP) technologies help them deal with data corruption by providing timely recovery to any point-in-time. But in this CDP process, the CDP system needs record every data changes, and then the extra system I/O operations increase greatly, the performance of information systems will be lower and the system cannot provide the best service. This paper discusses a method based buffer chains that can reduce the extra I/O operations from the disk. We have presented an implementation in the Linux kernel which provides continuous data protection service with higher performance under some buffer chains strategy. 10. Resilience as a way to improve business continuity: a multiple case study with large Nordic companies Mäkilä, Miikka 2014-01-01 This thesis observes the impacts of business interruptions on business, which is a relatively new area of research. Since the extant theory concentrates mainly on supply chain disruptions the understanding of business interruptions is narrow. Companies suffer increasingly from supply chain disruptions due to just-in-time strategies, globalization and outsourcing, but the risks that threaten companies' business continuity are much more diverse rendering this study to seek answers to fill the g... 11. Improving the maximum transmission distance of continuous-variable quantum key distribution using a noiseless amplifier Blandino, Rémi; Leverrier, Anthony; Barbieri, Marco; Etesse, Jean; Grangier, Philippe; Tualle-Brouri, Rosa 2012-01-01 International audience We show that the maximum transmission distance of continuous-variable quantum key distribution in presence of a Gaussian noisy lossy channel can be arbitrarily increased using a linear noiseless amplifier. We explicitly consider a protocol using amplitude and phase modulated coherent states with reverse reconciliation. We find that a noiseless amplifier with amplitude gain g can increase the maximum admissible losses by a factor 1/g^2. 12. Continuous Exercise but Not High Intensity Interval Training Improves Fat Distribution in Overweight Adults 2014-01-01 Objective. The purpose of this study was to assess the effect of high intensity interval training (HIIT) versus continuous aerobic exercise training (CONT) or placebo (PLA) on body composition by randomized controlled design. Methods. Work capacity and body composition (dual-energy X-ray absorptiometry) were measured before and after 12 weeks of intervention in 38 previously inactive overweight adults. Results. There was a significant group × time interaction for change in work capacity (P < ... 13. Sequence and structure continuity of evolutionary importance improves protein functional site discovery and annotation Wilkins, A D; Lua, R.; Erdin, S; Ward, R M; LICHTARGE, O 2010-01-01 Protein functional sites control most biological processes and are important targets for drug design and protein engineering. To characterize them, the evolutionary trace (ET) ranks the relative importance of residues according to their evolutionary variations. Generally, top-ranked residues cluster spatially to define evolutionary hotspots that predict functional sites in structures. Here, various functions that measure the physical continuity of ET ranks among neighboring residues in the st... 14. Successful treatment of Depot Medroxyprogesterone acetate-related vaginal bleeding improves continuation rates in Adolescents Kristin M. Rager; Amy Fowler; Hatim A. Omar 2006-01-01 High discontinuation rates for depot medroxyprogesterone acetate (DMPA) in adolescents may contribute to the number of unintended pregnancies. Many cite vaginal bleeding as a reason for discontinuing DMPA use. In this study, we attempted to determine if treating DMPA-associated vaginal bleeding with monophasic oral contraceptive pills (OCP) raised continuation rates. A total of 131 patients who reported vaginal bleeding while on DMPA were included in this study and 83 were treated with monoph... 15. Improved Continuous Tube Welding Due to Unique Process Sensor System and Process Control Dorsch, F.; Pfitzner, D.; Braun, H. A unique camera-based triple sensor system increases productivity, yield and quality of continuous welding of tubes and profiles. It combines high-precision seam tracking and beam positioning with weld spot visualization and characterization, and seam geometry measurement. The higher overall precision allows operating the process closer to its limits, online quality monitoring detects faults immediately. The process setup time is greatly reduced, and also the waste during startup is reduced. Finally, full documentation sets the basis for data traceability. 16. Continuous Energy Improvement in Motor Driven Systems - A Guidebook for Industry Gilbert A. McCoy and John G. Douglass 2014-02-01 This guidebook provides a step-by-step approach to developing a motor system energy-improvement action plan. An action plan includes which motors should be repaired or replaced with higher efficiency models, recommendations on maintaining a spares inventory, and discussion of improvements in maintenance practices. The guidebook is the successor to DOE’s 1997 Energy Management for Motor Driven Systems. It builds on its predecessor publication by including topics such as power transmission systems and matching driven equipment to process requirements in addition to motors. 17. Continuous Exercise but Not High Intensity Interval Training Improves Fat Distribution in Overweight Adults Shelley E. Keating 2014-01-01 Full Text Available Objective. The purpose of this study was to assess the effect of high intensity interval training (HIIT versus continuous aerobic exercise training (CONT or placebo (PLA on body composition by randomized controlled design. Methods. Work capacity and body composition (dual-energy X-ray absorptiometry were measured before and after 12 weeks of intervention in 38 previously inactive overweight adults. Results. There was a significant group × time interaction for change in work capacity (P<0.001, which increased significantly in CONT (23.8±3.0% and HIIT (22.3±3.5% but not PLA (3.1±5.0%. There was a near-significant main effect for percentage trunk fat, with trunk fat reducing in CONT by 3.1±1.6% and in PLA by 1.1±0.4%, but not in HIIT (increase of 0.7±1.0% (P=0.07. There was a significant reduction in android fat percentage in CONT (2.7±1.3% and PLA (1.4±0.8% but not HIIT (increase of 0.8±0.7% (P=0.04. Conclusion. These data suggest that HIIT may be advocated as a time-efficient strategy for eliciting comparable fitness benefits to traditional continuous exercise in inactive, overweight adults. However, in this population HIIT does not confer the same benefit to body fat levels as continuous exercise training. 18. Student Voices Speak Quality Assurance: Continual Improvement in Online Social Work Education Secret, Mary; Bentley, Kia J.; Kadolph, Jessie C. 2016-01-01 As social work education expands instruction through the rise of distance education, educators seek new ways to improve quality in online courses. Quality assurance standards and student feedback offer valuable insights to ensure satisfying and effective online learning experiences. An examination of these two assessment approaches concurrently in… 19. Co-Teaching as a School System Strategy for Continuous Improvement Walsh, James M. 2012-01-01 Co-teaching has increasingly been implemented over the past 20 years as a shared responsibility alternative to more restrictive special education models for providing service to students with disabilities. Results of local school system research in Maryland during this 20-year period are reviewed suggesting that improved special education student… 20. 78 FR 12221 - National School Lunch Program: Direct Certification Continuous Improvement Plans Required by the... 2013-02-22 ... than it actually is. To measure the actual impact of a large homeschooling population, for instance... Improvement Plans Required by the Healthy, Hunger-Free Kids Act of 2010, in the Federal Register (77 FR 4688... aggregate number of students who were terminated as a result of verification but who were reinstated... 1. Dot Hill reports third quarter 2001 results operating results continue to improve 2001-01-01 Dot Hill Systems Corp., a leading supplier of carrier-class data storage and storage area network solutions announced slighly improved financial results for the period ending Sept. 30, 2001. Of their products, SANnet Axis and the SANnet 7100 Fibre Channel storage system were selected as the essential storage components for the GRID demonstration at the High Performance Networking Forum Conference at CERN. 2. Improved bounds for perfect simulation of a continuous one-dimensional loss network Garcia, Nancy L.; Maric, Nevena 2005-01-01 Perfect simulation of an one-dimensional loss network on$\\R$with length distribution$\\pi$and cable capacity$Cis performed using the clan of ancestors method. Domination of the clan of ancestors by a branching process with longer memory improves the sufficient conditions for the perfect scheme to be applicable. 3. Improvements to the User Interface for LHCb's Software continuous integration system. Clemencic, M.; Couturier, B.; Kyriazi, S. 2015-12-01 The purpose of this paper is to identify a set of steps leading to an improved interface for LHCb's Nightly Builds Dashboard. The goal is to have an efficient application that meets the needs of both the project developers, by providing them with a user friendly interface, as well as those of the computing team supporting the system, by providing them with a dashboard allowing for better monitoring of the build job themselves. In line with what is already used by LHCb, the web interface has been implemented with the Flask Python framework for future maintainability and code clarity. The Database chosen to host the data is the schema-less CouchDB[7], serving the purpose of flexibility in document form changes. To improve the user experience, we use JavaScript libraries such as JQuery[11]. 4. Transformational Approach To School Leadership: Contribution To Continued Improvement Of Education Anca Nedelcu 2013-05-01 Full Text Available Over the last decades, an impressive number of conceptual models in the field of educational leadership have emerged; contingency or trait theories, situational, instructional, shared or distributed school leadership approaches, all tried to demonstrate their specific impact on school development and students achievement. The present paper is focused on exploring one of the foremost models, subject of systematic inquiry and controversial debates developed in relation with school or in nonschool organizations: transformational school leadership. The approach is considered a relevant support for school change process. Its contribution is analyzed in comparison with the benefits of other competing models, the aim of the paper being not to establish hierarchies but to gather significant solutions for better schooling. As a reconciliation solution, the integrative leadership model is also advocated. 5. THE ASSESSMENT METHODOLOGIES PTELR, ADRI AND CAE – THREE METHODOLOGIES FOR COORDINATING THE EFFORTS TO IMPROVE THE ORGANIZATIONAL PROCESSES TO ACHIEVE EXCELLENCE Cristina Raluca POPESCU; Gheorghe N. Popescu 2015-01-01 In the paper “The Assessment Methodologies PTELR, ADRI and CAE – Three Methodologies for Coordinating the Efforts to Improve the Organizational Processes to Achieve Excellence” the authors present the basic features of the assessment methodologies PTELR, ADRI and CAE that are designed to coordinate the efforts to improve the organizational processes in order to achieve excellence. In the first part of the paper (the introduction of the paper), the authors present the general background concer... 6. Effectiveness of Music Education for the Improvement of Reading Skills and Academic Achievement in Young Poor Readers: A Pragmatic Cluster-Randomized, Controlled Clinical Trial Hugo Cogo-Moreira; Clara Regina Brandão de Ávila; Ploubidis, George B; Jair de Jesus Mari 2013-01-01 INTRODUCTION: Difficulties in word-level reading skills are prevalent in Brazilian schools and may deter children from gaining the knowledge obtained through reading and academic achievement. Music education has emerged as a potential method to improve reading skills because due to a common neurobiological substratum. OBJECTIVE: To evaluate the effectiveness of music education for the improvement of reading skills and academic achievement among children (eight to 10 years of age) with reading... 7. Managing the Continuous Improvement Loop of Educational Systems: Students as key actors in program evaluation LASSUDRIE, Claire; KONTIO, Juha; ROUVRAIS, Siegfried 2013-01-01 International audience More and more, educational frameworks and accreditation bodies recommend implementing a system to evaluate and improve the quality of higher education institutions. This paper describes a student self-evaluation of a French engineering school which was carried out with an external institution as client. It describes the methodology and standards adopted by the students in order to conduct the evaluation, interview stakeholders, and rate compliance with maturity level... 8. Improved Particle Swarm Optimization with a Collective Local Unimodal Search for Continuous Optimization Problems 2014-01-01 A new local search technique is proposed and used to improve the performance of particle swarm optimization algorithms by addressing the problem of premature convergence. In the proposed local search technique, a potential particle position in the solution search space is collectively constructed by a number of randomly selected particles in the swarm. The number of times the selection is made varies with the dimension of the optimization problem and each selected particle donates the value i... 9. Improving the 5th Formers’ Continuous Writing Skills through the Creative Writing Module Mohana Ram Murugiah 2013-01-01 Writing is a complex task. The development of students’ writing skill depends on the teacher’s teaching strategy and also the materials used in the writing lesson. In the present study, the effectiveness of a creative writing module was examined that was designed to improve the writing skill of a group of excellent students. It was added with explicit teaching strategies. The selected group of students were students who were in the excellent group but lacked creativity and vocabulary in their... 10. Improving the 5th Formers’ Continuous Writing Skills through the Creative Writing Module Mohana Ram Murugiah 2013-07-01 Full Text Available Writing is a complex task. The development of students’ writing skill depends on the teacher’s teaching strategy and also the materials used in the writing lesson. In the present study, the effectiveness of a creative writing module was examined that was designed to improve the writing skill of a group of excellent students. It was added with explicit teaching strategies. The selected group of students were students who were in the excellent group but lacked creativity and vocabulary in their writing. The creative writing module was designed to help these students. Students’ improvement was observed through observation in the classrooms during the lessons and through writing task as well as interviews. Two observations were made. One was before the creative writing project was started and another after the completion of the entire task of the module. The interview was carried out to learn about the students’ perception of the module and how do they find the module has helped them. The result of the research showed that students have shown a great level of improvement in their writing skills. The outcome of this present study could be useful to assist language instructors in helping proficient learners to undergo a more effective second language learning experience. 11. Operational Improvements of Continuous Process with Tools of Lean Production - A Case Study in a Brazilian Petrochemical Francisco Uchoa Passos 2013-06-01 Full Text Available This study seeks to evaluate operational improvements in Brazilian petrochemical company Braskem, which has been using lean production management tools to monitor its processes. There was some improvement in plant efficiency, measured from the beginning of implementation of management tools Six Sigma and TPM. Thus, we investigated three efficiency indicators considered by the company of great importance for the competitiveness of the business: the physical loss of products, plant’s energy efficiency, and the utilization rate of assets. The differences observed in these indicators, before and after the use of the tools, were tested for its statistical significance, which revealed that the physical losses of ethylene and plant’s energy efficiency improved, almost reaching the performance considered as class world. As for the utilization rate of assets, although it has evolved positively, still is at a considerable distance from that performance standard. By registering operational improvements in a continuous process plant, with lean production tools, this study indicates that these instruments, even if they have no causal relation with the improvements, are suitable for continuous processes and could have a much broader use, oriented, first of all, by the general approach of process optimization and, somehow, regardless of the nature of productive activity. 12. An improved fiber tracking algorithm based on fiber assignment using the continuous tracking algorithm and two-tensor model★ Zhu, Liuhong; Guo, Gang 2012-01-01 This study tested an improved fiber tracking algorithm, which was based on fiber assignment using a continuous tracking algorithm and a two-tensor model. Different models and tracking decisions were used by judging the type of estimation of each voxel. This method should solve the cross-track problem. This study included eight healthy subjects, two axonal injury patients and seven demyelinating disease patients. This new algorithm clearly exhibited a difference in nerve fiber direction betwee... 13. Development and implementation of a virtual laboratory for training process improvement in the mechanics of continuous media González Rodrigo, Beatriz; Gomez Pulido, María Dolores; Hernando Mansilla, Félix; Isidro Gordejuela, Federico de; Castilla Heredia, Isabel; Prieto Muñoz, F.; Mosquera Feijoo, Juan Carlos; Fernández-Ordóñez Hernández, David 2013-01-01 The project arises from the need to develop improved teaching methodologies in field of the mechanics of continuous media. The objective is to offer the student a learning process to acquire the necessary theoretical knowledge, cognitive skills and the responsibility and autonomy to professional development in this area. Traditionally the teaching of the concepts of these subjects was performed through lectures and laboratory practice. During these lessons the students attitude was usually pa... 14. Improved yields of full-length functional human FGF1 can be achieved using the methylotrophic yeast Pichia pastoris. Fantoni, Adele; Bill, Roslyn M; Gustafsson, Lena; Hedfalk, Kristina 2007-03-01 We have produced human fibroblast growth factor 1 (hFGF1) in the methylotrophic yeast Pichia pastoris in order to obtain the large amounts of active protein required for subsequent functional and structural characterization. Four constructs were made to examine both intracellular and secreted expression, with variations in the location of the His6 tag at either end of the peptide. hFGF1 could be produced from all four constructs in shake flasks, but production was optimized by growing only the highest-yielding of these strains, which produced hFGF1 intracellularly, under tightly controlled conditions in a 3 L fermentor. One hundred and eight milligrams of pure protein was achieved per liter culture (corresponding to 0.68 mg of protein per gram of wet cells), the function of which was verified using NIH 3T3 cell cultures. This is a 30-fold improvement over previously reported yields of full-length hFGF1. PMID:17134911 15. Continuous Improvements to East Coast Abort Landings for Space Shuttle Aborts Butler, Kevin D. 2003-01-01 Improvement initiatives in the areas of guidance, flight control, and mission operations provide increased capability for successful East Coast Abort Landings (ECAL). Automating manual crew procedures in the Space Shuttle's onboard guidance allows faster and more precise commanding of flight control parameters needed for successful ECALs. Automation also provides additional capability in areas not possible with manual control. Operational changes in the mission concept allow for the addition of new landing sites and different ascent trajectories that increase the regions of a successful landing. The larger regions of ECAL capability increase the safety of the crew and Orbiter. 16. Effects of high cooling rates on the improvement of continuous steel casting microstructure A. Mahmutović 2014-04-01 Full Text Available This paper has researched into the influence of trace elements in steel, combined with new casting processes, on the microstructure and micro-segregation phenomenon in the case of structural steel. Thermocalc software has been applied for calculation of steel phase. In the paper, close attention has been paid to monitoring of the influence of the cooling rate in regard to solidification time and to the characteristic elements’ segregation coefficient. Higher cooling rates during solidification improve the microstructure and produce positive effects on the metallurgical quality of the steel cast. 17. Using activity-based costing and theory of constraints to guide continuous improvement in managed care. Roybal, H; Baxendale, S J; Gupta, M 1999-01-01 Activity-based costing and the theory of constraints have been applied successfully in many manufacturing organizations. Recently, those concepts have been applied in service organizations. This article describes the application of activity-based costing and the theory of constraints in a managed care mental health and substance abuse organization. One of the unique aspects of this particular application was the integration of activity-based costing and the theory of constraints to guide process improvement efforts. This article describes the activity-based costing model and the application of the theory of constraint's focusing steps with an emphasis on unused capacities of activities in the organization. PMID:10350791 18. Improved Middle-Temperature Strength of Unfired Slide Gate Plate for Continuous Casting of Steel Wang, Fucheng; Zhao, Lei; Fang, Wei; He, Xuan; Chen, Hui; Du, Xing; Chen, Huan 2015-11-01 Unfired Al2O3-C slide gate plate refractories bonded with novel silicon-modified phenolic resin (MPR) and additives of Al and Si were prepared. The MPR was synthesized by silica sol via in situ polymerization with lignin-phenolic resin. The results showed that the MPR with corundum owns a better wettability and higher char yield than commercial resin (CR). The middle-temperature mechanical properties such as cold modulus of rupture (CMOR), flexural modulus ( E), and force-displacement of Al2O3-C refractory specimens bonded with MPR were improved especially ranging from 673 K to 1073 K (400 °C to 800 °C). The results showed that CMOR of the specimens bonded with MPR coked at 873 K (600 °C) had a considerable improvement with 7.04 MPa in sharp contrast to 3.31 MPa for CR-bonded specimens. It was suggested that the special organic-inorganic network structure of MPR and good wettability with corundum enhanced the bonding strength of Al2O3-C slide gate plate refractories. 19. Continuous biohydrogen production using cheese whey: Improving the hydrogen production rate Davila-Vazquez, Gustavo; Cota-Navarro, Ciria Berenice; Razo-Flores, Elias [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Lomas 4a seccion, C.P. 78216, San Luis Potosi, S.L.P (Mexico); Rosales-Colunga, Luis Manuel; de Leon-Rodriguez, Antonio [Division de Biologia Molecular, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Lomas 4a seccion, C.P. 78216, San Luis Potosi, S.L.P (Mexico) 2009-05-15 Due to the renewed interest in finding sustainable fuels or energy carriers, biohydrogen (Bio-H{sub 2}) from biomass is a promising alternative. Fermentative Bio-H{sub 2} production was studied in a continuous stirred tank reactor (CSTR) operated during 65.6 d with cheese whey (CW) as substrate. Three hydraulic retention times (HRTs) were tested (10, 6 and 4 h) and the highest volumetric hydrogen production rate (VHPR) was attained with HRT of 6 h. Therefore, four organic loading rates (OLRs) at a fixed HRT of 6 h were tested thereafter, being: 92.4, 115.5, 138.6 and 184.4 g lactose/L/d. The highest VHPR (46.61 mmol H{sub 2}/L/h) and hydrogen molar yield (HMY) of 2.8 mol H{sub 2}/mol lactose were found at an OLR of 138.6 g lactose/L/d; a sharp fall in VHPR occurred at an OLR of 184.4 g lactose/L/d. Butyric, propionic and acetic acids were the main soluble metabolites found, with butyric-to-acetic ratios ranging from 1.0 to 2.4. Bacterial community was identified by partial sequence analysis of the 16S rRNA and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The results showed that at HRT of 10 h and 6 h were dominated by the Clostridium genus. The VHPR attained in this study is the highest reported value for a CSTR system using CW as substrate with anaerobic sludge as inoculum and represents a 33-fold increase compared to a previous study. Thus, it was demonstrated that continuous fermentative Bio-H{sub 2} production from CW can be significantly enhanced by an appropriate selection of parameters such as HRT and OLR. Enhancements in VHPR are significant because it is a critical parameter to determine the full-scale practical application of fermentation technologies that will be used for sustainable and clean energy generation. (author) 20. Clinical audit as a tool of continuous improvement of quality in radiology Medical diagnosis and treatment including X -rays, nuclear medicine and radiotherapy , are the largest man-made sources of radiation exposure. The medical use of ionising radiation continues to expand, and is moving towards more complex procedures entailing higher exposures. Directive 97/43/EURATOM, on health protection of individuals against the dangers of ionizing radiation in relation to medical exposures acknowledged that medical practices using ionizing radiation are developing rapidly and that they are from a radiation protection point of view of regulatory concern. Our contribution summarizes the main recommendations of the Guidelines and the major problems of implementation of Clinical audits in Slovakia, which are: Incomplete national legislation for clinical audit; Methods of financing; Lack of formal framework of auditing; Poor understanding of the purpose and contents of clinical audits; Lack of criteria for the standards of good practices; Difficulty to employ sufficient number of auditors; Insufficient time available for auditors; Lack of specific training of auditors; Need of technological modernization of radiology equipment to meet quality standards. The need for harmonization of clinical audits has been recognized by all countries which replied to the questionnaire, including Slovakia and therefore it should be implemented in radiation protection regulations of Health ministry. (authors) 1. Continuous improvement of operation and maintenance conditions of french PWR nuclear islands Improvement of the nuclear island design, to facilitate maintenance and working conditions during plant shutdown, has been a subject of particular attention within the French PWR program. Standardization and industrial concentration created an unusually favourable context for approaching this objective. Progress efforts supported by the feedback of actual operating experience were pursued in the areas of plant layout-equipment installation, and on the design and technology of the component themselves. The progress efforts on the design and technology of the components were pursued along several paths including: - the resistance increase of specific parts submitted to various forms of in-service damage, - the reduction of the extent and duration of work during plant outages and - the reduction of the Occupational Radiation Exposure (ORE), one of the most important axes of development, through the appropriate selection of less releasing materials, the implementation of more efficient decontamination systems and by the use of robots 2. Note: Continuing improvements on the novel flat-response x-ray detector This note describes multi-updates of the novel flat-response x-ray detector in fabrication technology, experimental application, and data uncertainty evaluation. Unlike the previous design, the compound filter is combined into one piece through an improved fabrication process that greatly enhanced its self-supporting capability. A method of pinhole-array imaging is introduced into the experimental application process to stop any debris from the hohlraum and to uniformly reduce the radiation flux. The experimental results show that this method works well. Furthermore, a method of uncertainty evaluation of the radiation flux measurement by the novel flat-response x-ray detector has been developed. The influence of the radiation spectrum to the flux measurement is analyzed. The evaluation shows that the relative uncertainty of the radiation flux is about 10% in higher radiation temperature condition (Tr > 150 eV) and 16% in lower radiation temperature condition (Tr < 100 eV). 3. Continuous intratracheal insufflation of oxygen improves the efficacy of mechanical chest compression-active decompression CPR. Steen, Stig; Liao, Qiuming; Pierre, Leif; Paskevicius, Audrius; Sjöberg, Trygve 2004-08-01 The aim of the present study was to compare the efficacy of intratracheal continuous insufflation of oxygen (CIO) with intermittent positive pressure ventilation (IPPV) regarding gas exchange and haemodynamics during mechanical chest compression-active decompression cardiopulmonary resuscitation (mCPR) provided by the LUCAS device. Ventricular fibrillation (VF) was induced electrically and ventilation was discontinued in 16 pigs, mean body weight 23 kg (range 22-27 kg). They were randomized into two groups (CIO versus IPPV). After 8 min of VF, mCPR was started and run for 30 min in normothermia, after which defibrillation was attempted during on-going mCPR. Return of spontaneous circulation was obtained in eight of eight CIO pigs and in four of eight IPPV pigs. Arterial oxygen tension (P < 0.05) and coronary perfusion pressure (P < 0.01) were significantly higher in the CIO pigs. Arterial CO(2)-tension was subnormal in both groups and significantly (P < 0.05) lower in the IPPV-pigs (around 4.5 versus 3.0 kPa). The intratracheal pressure differed significantly (P < 0.001) between the two groups. It was negative in each decompression phase in the IPPV pigs in spite of 6 mmHg of PEEP. The CIO pigs had a positive intratracheal pressure during the whole cycle of mCPR, with a minimum pressure of 8 mmHg during each decompression phase. To conclude, mCPR combined with CIO gave adequate ventilation and significantly better oxygenation and coronary perfusion pressure than mCPR combined with IPPV. PMID:15294408 4. Assessing the Impact of Continuous Quality Improvement on Clinical Practice: What It Will Take to Accelerate Progress Shortell, Stephen M.; Bennett, Charles L.; Byck, Gayle R. 1998-01-01 The literature on continuous quality improvement (CQI) has produced some evidence, based on nonrandomized studies, that its clinical application can improve outcomes of care while reducing costs. Its effectiveness is enhanced by a nucleus of physician involvement, individual practitioner feedback, and a supportive organizational culture. The few randomized studies, however, suggest no impact of CQI on clinical outcomes and no evidence to date of organization-wide improvement in clinical performance. Further, most studies address misuse issues and avoid examining overuse or underuse of services. The clinical application of CQI is more likely to have a pervasive impact when it takes place within a supportive regulatory and competitive environment, when it is aligned with financial incentives, and when it is under the direction of an organizational leadership that is committed to integrating all aspects of the work. PMID:9879304 5. Proposals for an effective application of the continuous improvement at the ININ according to the IAEA 50-C/SG-Q new code This work contains the requirements of continuous improvement contained in the IAEA new code Quality assurance for safety in nuclear power plants and other nuclear installations, code 50-C/SG-Q. Assuming that it was the base for to elaborate the review No. 5 of the Quality assurance plan at ININ, it was done an analysis to give proposals for the application of continuous improvement in effective way. The relevant points which must be taken in account at the continuous improvement process are: Direction responsibility, involucring of all personnel, process planning, education and training, elaboration of improvement projects, investigation of processes which can be improved, continuation of the improvement process and its evaluation. With the implantation of an effective continuous improvement system it will be obtained to get a better quality and a more efficient safety. (Author) 6. Proposals for improving the performance of the continuation power flow; Propostas para a melhoria do desempenho do fluxo de carga continuado Bonini Neto, A.; Magalhaes, E.M.; Alves, D.A. [Universidade Estadual Paulista (FEIS/UNESP), Ilha Solteira, SP (Brazil). Fac. de Engenharia. Dept. Engenharia Eletrica], Emails: alfredoneto@aluno.feis.unesp.br, elisabete.magalhaes@yahoo.com.br, dalves@dee.feis.unesp.br 2009-07-01 This paper aims to present a proposal for improving the performance of continuation power flow. For this propose the addition of an equation of one straight line in the plane formed by the load factor variables and bus voltage magnitude. It becomes possible with this, more precise determination of the maximum loading point without calculating a large number of points P-V curve. The work also shows that it is possible to obtain a reduction in computing time required for obtain P-V curve. The reduction is achieved by upgrading Jacobian matrix only when the system suffer some significant change (changing the type of PV bar to PQ or vice versa), instead of updating it at each iteration. 7. A review of strategies for improving the degradation properties of laminated continuous-fiber/epoxy composites with carbon-based nanoreinforcements Lubineau, Gilles 2012-06-01 Continuous-fiber/epoxy-matrix laminated composites are a key structural material for aeronautical and aerospace applications. Introducing nanoscale reinforcements to these materials is a possible way to achieve improved mechanical properties. To date, much work has been done on nano-reinforced polymers. However, few systematic studies concerning the effect of the nanoreinforcements on the mechanical properties on laminated composites were conducted. This paper presents a systematic review of the mechanisms of degradation in laminated structures and considers various nanoreinforcement strategies in the light of well-known mechanisms of degradation and phenomenologies in classical laminated composites. We also discuss various nanoreinforcement strategies in terms of their potential to reduce degradation on every scale. In addition, we review studies conducted on the role that nanoreinforcements play in mechanical properties involved in structural simulation and design. The degradation mechanisms are systematically considered to provide a full picture of each reinforcement strategy. © 2012 Elsevier Ltd. All rights reserved. 8. Continuous improvement of the regulatory framework for the control of medical exposure One of the key elements to guide the improvement of the regulatory control is the availability of a self-assessment tool for regulatory performance. Although there is general guidance on self-assessment for regulators and users (IAEA), there is a need for more specific advice on how to address challenges and difficulties faced by regulatory bodies, when regulating radiation protection of patients. Examples of these challenges are the need for regulatory initiatives, in cooperation with health and education authorities, professional bodies and equipment suppliers, and to put in place necessary elements that are beyond responsibility of individual user of radiation, to enable them compliance with safety standards. Purpose: Within the programme of the Ibero American Forum of Nuclear and Radiation Safety Regulatory Organizations, a project to develop such a self-assessment tool for the regulatory control of medical exposure has been designed. Method: National experiences in transposing and enforcing the international radiation safety standards, as to how the requirements are included in national regulations are reviewed. Further, difficulties to the implementation of safety requirements are analyzed and a self-assessment approach and possible regulatory solutions a are presented. Results and discussion: In this study the following documents are being produced: 1) transposition of international requirements into national regulations in the six countries of the Forum, 2) difficulties to implement and enforce the requirements, 3) guidance on self-assessment of regulatory framework for medical exposure, 4) suggested contribution to the revision of international radiation safety standards. (author) 9. Real-time tracking data drive process improvements, even while ED volumes continue to climb. 2012-06-01 Christiana Hospital in Newark, DE, has been able to dramatically reduce length-of-stay in the ED by making use of data derived from a real-time location system (RTLS) that tracks the movements of patients, providers, and staff. Administrators say that while some efficiencies are gained from the system alone, most of the positive impact is derived from using the RTLS data to focus on specific processes and make refinements. Within one year of implementing the RTLS technology, LOS in the ED was reduced by 40 minutes for admitted patients and 18 to 20 minutes for the treated-and-released population. A work group focused on process improvements in the ED's fast track section reduced the average LOS from 2.5 hours to 60 minutes or less. Similarly, a work group focused on the ESI 3 population reduced the average treatment time for this population from 5 or 6 hours to 3.4 hours. Administrators say key steps toward a successful RTLS implementation are careful planning for how you want to use the technology, and alleviating staff concerns about why their movements are being tracked. PMID:22645845 10. Continuing with the Fresnel database: experimental setup and improvements in 3D scattering measurements In this paper, the experimental setup and the improvements required to obtain further measurements for the third opus of the Fresnel Database are presented. The most original feature of those new datasets is the fact that they were obtained with three-dimensional targets instead of the two-dimensional ones used in the two previous opuses. The measurements were performed all around the targets under test to collect enough information about the objects to be able to perform inversion on their scattered fields. As the targets were small in comparison with the wavelength, the challenge here was to extract these small scattered fields from the measurements, and a specific post-processing procedure had to be designed to compensate for the drift errors. The five targets selected for the database are presented, including the Myster target, a hitherto undivulged target that is presented in this paper for the first time, i.e., at the same time as the submissions of all the other contributors to this special section. Some scattered field comparisons are also presented 11. WATTec '92. Innovation in the 21st century: Excellence through continuous improvement WATTec '92 will concentrate on five areas of major importance in today's world: Training and Education - What can be done to meet future needs and ensure that new technology is applied in the workplace? What innovative approaches can be taken to interest young people in careers in science and engineering? Productivity - What is the role of the scientist and engineer in the factory of the future? What must be done by large industries and small manufacturers to compete in the global economy? What innovative steps can be taken to make the most of our nation's resources and advantages while reducing disadvantages relative to others in the global economy? Technology - What are the technologies of the future and how will we use, share, understand and adopt these technologies? And how do we transfer them, not only within an individual business or institution, but to laboratories, educators, and others? How do we extend America's record for inventiveness while improving commercialization and work leadership in the technologies we create? Resources - What are the materials that will shape the world and how will they shape the technical profession in the 21st Century? How do we make the most of our natural resources, conserving them for best uses while protecting the environment and meeting the demands of international competition? The Nineteenth Annual WATTec Conference and Exhibition will focus on these and related questions in wide-ranging sessions sponsored by more than 40 technical professional societies. Papers within the scope of the Energy Data Base have been processed separately 12. Main ways and suitable technologies of improving economic benefits for uranium ore heap leaching in China (to be continued) Combining with practice of China's uranium ore heap leaching, the author proposes main ways and suitable technologies in the fields of emphasizing feasibility research, adopting strengthened technologies, improving equipment level, optimizing control technological factors and developing application range and so on, which include adopting acid-curry and ferric sulphate-trickle leaching process, bacteria heap leaching, countercurrent heap leaching, selecting advanced material of heap bottom, developing large mechanized heap construction equipment and methods, popularizing drip irrigation distributing solution, optimizing heap leaching process parameters, as well as developing recovery equipment suited to heap leaching, etc, in order to increase leaching rate, reduce heap leaching period and achieve more economic benefits 13. Sustainable MSD prevention: management for continuous improvement between prevention and production. Ergonomic intervention in two assembly line companies. Caroly, S; Coutarel, F; Landry, A; Mary-Cheray, I 2010-07-01 To increase output and meet customers' needs, companies have turned to the development of production management systems: Kaizen, one piece flow, Kanban, etc. The aim of such systems is to accelerate decisions, react to environmental issues and manage various productions. In the main, this type of management system has led to the continuous improvement of production performance. Consequently, such production management systems can have unexpected negative effects on operators' health and safety. Conversely, regulation and control systems focusing on work-related risks have obliged firms to implement health and safety management systems such as OHSAS 18001. The purpose of this type of system, also based on continuous improvement, is to reduce risks, facilitate work-related activities and identify solutions in terms of equipment and tools. However, the prevention actions introduced through health and safety systems often result in other unexpected and unwanted effects on production. This paper shows how companies can improve the way they are run by taking into account both types of management system. PMID:20097327 14. An improved fiber tracking algorithm based on fiber assignment using the continuous tracking algorithm and two-tensor model Liuhong Zhu; Gang Guo 2012-01-01 This study tested an improved fiber tracking algorithm, which was based on fiber assignment using a continuous tracking algorithm and a two-tensor model. Different models and tracking decisions were used by judging the type of estimation of each voxel. This method should solve the cross-track problem. This study included eight healthy subjects, two axonal injury patients and seven demyelinating disease patients. This new algorithm clearly exhibited a difference in nerve fiber direction between axonal injury and demyelinating disease patients and healthy control subjects. Compared with fiber assignment with a continuous tracking algorithm, our novel method can track more and longer nerve fibers, and also can solve the fiber crossing problem. 15. Biotherapic T. cruzi 17DH when continuously used clinically improves mice infected with T. cruzi. Silvana Marques de Araujo 2011-09-01 treatment ways using biotherapic T. cruzi 17DH showed differences in the clinical evolution. The treatment using biotherapic diluted in water initially shows hypothermia, with subsequent recovery of normal temperature (p=0.05 (Fig1. The weight curve shows a better evolution in mice treated with water compared to control groups (p=0.055 and the groups treated by gavage (p=0.0064. Feed and water intake did not differ among the groups. While the mice that were treated with biotherapic diluted in water showed a slight level of ruffled fur, the mice in control groups and the ones treated by gavage showed a more intense level of ruffled fur (p=0.00001. The difference in the evolution of mortality among the groups was significant (p=0.034, while in the group treated with biotherapic diluted with water, the mortality rate started later, reaching the maximum of 90%. This group showed a better clinical result, expressed by the smaller extent of ruffled fur, a better evolution of the temperature curve and higher gain of weight. This is an important result because the Y strain of T. cruzi has a mortality rate of 100% in mice, showing once again the good performance of biotherapic in this model of infection. Conclusion: The use of biotherapic T. cruzi 17DH for a long period causes clinical improvement of the infected mice with Trypanosoma cruzi. The clinical use of these results in human beings should consider the allometric medicine dosage which takes into account the metabolic rate of each organism. 16. [A New Method for Eliminating Background Signal Drift to Improve the Detection Precision in Continuous Harmonic Detection]. Zhao, Ying; Zhao, Xue-hong; Wang, Zhe; Zhang, Rui; Wang, Yan 2015-11-01 To overcome the second harmonic background signal drift in gas continuous detection based on tunable diode laser absorption spectroscopy(TDLAS), a new method of background elimination was proposed by changing center current of the laser. This method can eliminated the effects of background signal drifting on concentration inversion. Based on the wavelength modulation theory, the theoretical expression of the second harmonic of the background signal is derived. In addition, the second harmonic background signal components and the factors that affect it are described. In different working temperatures, the relationship curve between thelaser current and output light intensity. In the process of continuous detection, we analyzes the feasibility ofchangingthe laser center current extraction of background signal. Combined with the principle of the background signal searching, the LabView flow chart was designed to search background center current. Ammonia (NH₃) was detected by the TDLAS experimental system, which demonstrated the feasibility of the new method. The range of experiment parameters and the range of background center current searches were determined, in the situation that there was only one absorption line in the full laser workspace. The experimental results showed that this method realizes background signal extraction, reduces the error of concentration inversion and the effects of concentration inversion bybackground signal. Thus it improved the detection accuracy of the concentration. In the continuous detection experiment, the standarddeviation of inversion concentration reduced from 2.688 3 to 1.856 1, which demonstrated. that the degree of dispersion of detected concentration is reduced, even eliminate the effects of background signal drifting on concentration inversion and the accuracy of detection is improved. This method provides an effective background drifting elimination approach for improving the detection accuracy of the concentration. PMID 17. Obtaining accreditation by the pharmacy compounding accreditation board, part 3: developing a program of qualtity assurance and continuous qualtiy improvement. Cabaleiro, Joe 2008-01-01 Before a compounding pharmacy can receive accreditation from the Pharmacy Compounding Accreditation Board, the pharmacy must show evidence of both quality assurance activities and continuous quality improvement activities. Although quality assurance data gathering and monitoring can be integrated into pharmacy activities fairly easily, the coninuous quality improvement program may take a little more time and effort to implement . Before integrating these programs, compounding pharmacists must have a complete understanding of the differences between these two programs. Even if accreditation with the Pharmacy Compounding Accreditation Board is not being considered, it is important that compounding pharmacies have these two programs implemented. In the long run, it will pay off in higher quality services, error prevention, and perhaps greater efficiency of pharmacy operations. PMID:23969712 18. Physical activity intervention (Movi-Kids) on improving academic achievement and adiposity in preschoolers with or without attention deficit hyperactivity disorder: study protocol for a randomized controlled trial Sánchez López, Mairena; Pardo Guijarro, María Jesús; Gutiérrez Díaz del Campo, David; Silva, Pedro; Martínez Andrés, María; Gulías González, Roberto; Díez Fernández, Ana; Franquelo Morales, Pablo; Martínez Vizcaíno, Vicente 2015-01-01 Background The prevention of obesity and improvement of academic achievement in children are concerns of industrialized societies. Obesity has been associated with psychological disorders, including attention deficit hyperactivity disorder, whose prevalence has been estimated at 6.8 % in Spanish children and adolescents. It is known that physical activity is positively related to academic achievement and negatively related to the risk of obesity in children. However, studies to test the effec... 19. Improved Minimum Entropy Filtering for Continuous Nonlinear Non-Gaussian Systems Using a Generalized Density Evolution Equation Jinliang Xu 2013-06-01 Full Text Available This paper investigates the filtering problem for multivariate continuous nonlinear non-Gaussian systems based on an improved minimum error entropy (MEE criterion. The system is described by a set of nonlinear continuous equations with non-Gaussian system noises and measurement noises. The recently developed generalized density evolution equation is utilized to formulate the joint probability density function (PDF of the estimation errors. Combining the entropy of the estimation error with the mean squared error, a novel performance index is constructed to ensure the estimation error not only has small uncertainty but also approaches to zero. According to the conjugate gradient method, the optimal filter gain matrix is then obtained by minimizing the improved minimum error entropy criterion. In addition, the condition is proposed to guarantee that the estimation error dynamics is exponentially bounded in the mean square sense. Finally, the comparative simulation results are presented to show that the proposed MEE filter is superior to nonlinear unscented Kalman filter (UKF. 20. Improvements in SIMS continue Cluster ion bombardment is at the forefront of current ToF-SIMS research, particularly when examining the feasibility of molecular depth profiling and three-dimensional imaging applications. It has become increasingly clear that secondary ion emission after cluster projectile impact results from a radically different sputtering mechanism than the linear collision cascades that dominate after atomic ion bombardment. The new physics involved with cluster ion impacts dramatically change the traditional approaches toward sample analysis with the SIMS technique. Several new ion bombardment properties have emerged from experimental and theoretical work involving cluster ions such as Au3+, Bi3+, SF5+, and C60+-all of which are commercially available ion sources. These new properties lead to new rules for traditional static SIMS experiments, provoking new methodologies, and introducing new applications-especially where high mass sensitivity and high-resolution imaging of organic and biological materials are necessary. This paper aims to elucidate recent experimental and theoretical work on these new cluster ion properties and offers insights into how these special properties can be used for future experiments and applications 1. Preventive effect of continuous quality improvement on the malnutrition,inflammation,peritoneal dialysis adequacy and cardiovascular events in elderly peritoneal dialysis patients 赵班 2013-01-01 Objective To investigate the preventive effect of continuous quality improvement (CQI) on malnutrition,inflammation,peritoneal dialysis adequacy and cardiovascular events in elderly patients undergoing peritoneal dialysis.Methods A single-center prospective self-controlled study was performed.32 stable elderly patients to undergo continuous ambulatory peritoneal dialysis (CAPD) were included.The continuous quality improvement program was conducted by using the 4-step problem-solving 2. Improved cellulose conversion to bio-hydrogen with thermophilic bacteria and characterization of microbial community in continuous bioreactor Thermophilic hydrogen fermentation of cellulose was evaluated by a long term continuous experiment and batch experiments. The continuous experiment was conducted under 55 °C using a continuously stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 10 day. A stable hydrogen yield of 15.4 ± 0.23 mol kg−1 of cellulose consumed was maintained for 190 days with acetate and butyrate as the main soluble byproducts. An analysis of the 16S rRNA sequences showed that the hydrogen-producing thermophilic cellulolytic microorganisms (HPTCM) were close to Thermoanaerobacterium thermosaccharolyticum, Clostridium sp. and Enterobacter cloacae. Batch experiment demonstrated that the highest H2 producing activity was obtained at 55 °C and the ultimate hydrogen yield and the metabolic by-products were influenced greatly by temperatures. The effect of temperature variation showed that the activation energy for cellulose and glucose were estimated at 103 and 98.8 kJ mol−1, respectively. - Highlights: • Continuous cellulosic-hydrogen fermentation was conducted at 55 °C. • Hydrogen yield was improved to 15.4 mol kg−1 of consumed-cellulose. • The cellulosic hydrogen bacteria were close to Clostridia and Enterobacter genus. • The mixed microflora produced H2 within a wide range of temperatures (35 °C–65 °C). • Activation energy of cellulose and glucose were 103 and 98.8 kJ mol−1, respectively 3. The Academic Backbone: longitudinal continuities in educational achievement from secondary school and medical school to MRCP(UK) and the specialist register in UK medical students and doctors McManus, I.; Woolf, K.; DACRE, J; Paice, E; Dewberry, C. 2013-01-01 Background: Selection of medical students in the UK is still largely based on prior academic achievement, although doubts have been expressed as to whether performance in earlier life is predictive of outcomes later in medical school or post-graduate education. This study analyses data from five longitudinal studies of UK medical students and doctors from the early 1970s until the early 2000s. Two of the studies used the AH5, a group test of general intelligence (that is, intellectual aptitud... 4. Improving Dairy Organizational Communication from the Veterinarian's Perspective: Results of a Continuing Veterinary Medical Education Pilot Program. Moore, Dale A; Sischo, William M; Kurtz, Suzanne; Siler, Julie D; Pereira, Richard V; Warnick, Lorin D; Davis, Margaret A 2016-01-01 The increasing size and complexity of US dairy farms could make it more difficult for a veterinary practitioner to effectively communicate protocol recommendations for prevention or treatment on the farm. A continuing education workshop was set up based on the results of research on dairy organizational communication on dairy farms, which resulted in a tool to assess dairy communication structure and flow. The workshop specifically focused on communication structure and whom to talk to when implementing health care changes in calf rearing. In addition, modern methods of veterinary-client communication knowledge and skills were provided. Primary outcomes of the workshops were to obtain feedback from participants about research findings and the communication model, to improve awareness about the complexity of communication structures on dairy farms, and to change participants' knowledge and skills associated with on-farm communication by providing communication theory and skills and an approach to evaluate and improve dairy organizational communication. Of the 37 participants completing the pre-program assessment, most recognized a need for themselves or their practice to improve communication with clients and farm employees. After the program, most participants were confident in their new communication skills and would consider using them. They highlighted specific new ideas they could apply in practice, such as conducting a "communication audit." The results from the assessment of this communication workshop, focused on dairy veterinarians, highlighted the need for communication training in this sector of the profession and practitioners' desire to engage in this type of training. PMID:26751909 5. Barriers and facilitators to implementing continuous quality improvement programs in colonoscopy services: a mixed methods systematic review Candas, Bernard; Jobin, Gilles; Dubé, Catherine; Tousignant, Mario; Abdeljelil, Anis Ben; Grenier, Sonya; Gagnon, Marie-Pierre 2016-01-01 Background and aim: Continuous quality improvement (CQI) programs may result in quality of care and outcome improvement. However, the implementation of such programs has proven to be very challenging. This mixed methods systematic review identifies barriers and facilitators pertaining to the implementation of CQI programs in colonoscopy services and how they relate to endoscopists, nurses, managers, and patients. Methods: We developed a search strategy adapted to 15 databases. Studies had to report on the implementation of a CQI intervention and identified barriers or facilitators relating to any of the four groups of actors directly concerned by the provision of colonoscopies. The quality of the selected studies was assessed and findings were extracted, categorized, and synthesized using a generic extraction grid customized through an iterative process. Results: We extracted 99 findings from the 15 selected publications. Although involving all actors is the most cited factor, the literature mainly focuses on the facilitators and barriers associated with the endoscopists’ perspective. The most reported facilitators to CQI implementation are perception of feasibility, adoption of a formative approach, training and education, confidentiality, and assessing a limited number of quality indicators. Receptive attitudes, a sense of ownership and perceptions of positive impacts also facilitate the implementation. Finally, an organizational environment conducive to quality improvement has to be inclusive of all user groups, explicitly supportive, and provide appropriate resources. Conclusion: Our findings corroborate the current models of adoption of innovations. However, a significant knowledge gap remains with respect to barriers and facilitators pertaining to nurses, patients, and managers. PMID:26878037 6. In Their Own Words: Erasing Deficits and Exploring What Works to Improve K-12 and Postsecondary Black Male School Achievement Warren, Chezare A.; Douglas, Ty-Ron M. O.; Howard, Tyrone C. 2016-01-01 This article outlines the imperative for strengths-based research to counter deficit perceptions and perspectives of Black males in contemporary discussions of their school achievement in the United States. The importance of young men of color in shaping research agendas, practice, and public policy is argued followed by a brief overview of the… 7. Neurofeedback as an Intervention to Improve Reading Achievement in Students with Attention- Deficit/Hyperactivity Disorder, Inattentive Subtype La Marca, Jeffry P.; O'Connor, Rollanda E. 2016-01-01 Research consistently demonstrates that attention deficits have a deleterious effect on academic achievement. Impairments in attention, and not hyperactivity/impulsivity, are associated with learning difficulties and academic problems in students with attention-deficit/hyperactivity disorder (ADHD). To date, most studies have focused on symptoms… 8. Improving Reading Achievement of Chapter 1 Pull-Out Students through Self-Esteem Building Classes Involving Buddy Group and Teacher Participation. Hershfield, Marlene A practicum attempted to improve the low reading achievement of Chapter 1 students in a low socioeconomic fifth-grade class by implementing a self-esteem building program. Activities were designed in a workbook format to complement class instruction in self-esteem building exercises. An emphasis on critical thinking skills was incorporated into… 9. The Efforts to Improve Mathematics Learning Achievement Results of High School Students as Required by Competency-Based Curriculum and Lesson Level-Based Curriculum Sidabutar, Ropinus 2016-01-01 The research was aimed to investigate the effect of various, innovated teaching models to improved the student's achievement in various topic in Mathematics. The study was conduct experiment by using innovated teaching with contextual, media and web which are the compared. with conventional teaching method. The result showed the innovation in the… 10. Accreditation council for graduate medical education (ACGME annual anesthesiology residency and fellowship program review: a "report card" model for continuous improvement Long Timothy R 2010-02-01 Full Text Available Abstract Background The Accreditation Council for Graduate Medical Education (ACGME requires an annual evaluation of all ACGME-accredited residency and fellowship programs to assess program quality. The results of this evaluation must be used to improve the program. This manuscript describes a metric to be used in conducting ACGME-mandated annual program review of ACGME-accredited anesthesiology residencies and fellowships. Methods A variety of metrics to assess anesthesiology residency and fellowship programs are identified by the authors through literature review and considered for use in constructing a program "report card." Results Metrics used to assess program quality include success in achieving American Board of Anesthesiology (ABA certification, performance on the annual ABA/American Society of Anesthesiology In-Training Examination, performance on mock oral ABA certification examinations, trainee scholarly activities (publications and presentations, accreditation site visit and internal review results, ACGME and alumni survey results, National Resident Matching Program (NRMP results, exit interview feedback, diversity data and extensive program/rotation/faculty/curriculum evaluations by trainees and faculty. The results are used to construct a "report card" that provides a high-level review of program performance and can be used in a continuous quality improvement process. Conclusions An annual program review is required to assess all ACGME-accredited residency and fellowship programs to monitor and improve program quality. We describe an annual review process based on metrics that can be used to focus attention on areas for improvement and track program performance year-to-year. A "report card" format is described as a high-level tool to track educational outcomes. 11. Efficacy of an integrated continuing medical education (CME) and quality improvement (QI) program on radiation oncologist (RO) clinical practice Purpose: There has been little radiation oncologist (RO)-specific research in continuing medical education (CME) or quality improvement (QI) program efficacy. Our aim was to evaluate a CME/QI program for changes in RO behavior, performance, and adherence to department protocols/studies over the first 12 months of the program. Methods and Materials: The CME/QI program combined chart audit with feedback (C-AWF), simulation review AWF (SR-AWF), reminder checklists, and targeted CME tutorials. Between April 2003 and March 2004, management of 75 patients was evaluated by chart audit with feedback (C-AWF) and 178 patients via simulation review audit (SR-AWF) using a validated instrument. Scores were presented, and case management was discussed with individualized educational feedback. RO behavior and performance was compared over the first year of the program. Results: Comparing the first and second 6 months, there was a significant improvement in mean behavior (12.7-13.6 of 14, p = 0.0005) and RO performance (7.6-7.9 of 8, p = 0.018) scores. Protocol/study adherence significantly improved from 90.3% to 96.6% (p = 0.005). A total of 50 actions were generated, including the identification of learning needs to direct CME tutorials, the systematic change of suboptimal RO practice, and the alteration of deficient management of 3% of patients audited during the program. Conclusion: An integrated CME/QI program combining C-AWF, SR-AWF, QI reminders, and targeted CME tutorials effectively improved targeted RO behavior and performance over a 12-month period. There was a corresponding increase in departmental protocol and study adherence 12. Semicoherent searches for continuous gravitational waves: improving robustness versus transient disturbances and increasing sensitivity to transient signals Keitel, David 2015-01-01 The vulnerability of standard detection methods for long-duration quasi-monochromatic gravitational waves from non-axisymmetric rotating neutron stars ('continuous waves', CWs) to single-detector instrumental artifacts was addressed in past work [Keitel, Prix, Papa, Leaci and Siddiqi, Phys. Rev. D 89, 064023 (2014)] by a Bayesian approach. An explicit model of persistent single-detector disturbances led to a generalized detection statistic with improved robustness against such artifacts. Since many strong outliers in semicoherent searches of LIGO data are caused by transient disturbances that last only a few hours, we extend this approach to cover transient disturbances, and demonstrate increased robustness in realistic simulated data. Besides long-duration CWs, neutron stars could also emit transient signals which, for a limited time, also follow the CW signal model (tCWs). As a pragmatic alternative to specialized transient searches, we demonstrate how to make standard semicoherent CW searches more sensitiv... 13. Recommended techniques for effective maintainability. A continuous improvement initiative of the NASA Reliability and Maintainability Steering Committee 1994-01-01 This manual presents a series of recommended techniques that can increase overall operational effectiveness of both flight and ground based NASA systems. It provides a set of tools that minimizes risk associated with: (1) restoring failed functions (both ground and flight based); (2) conducting complex and highly visible maintenance operations; and (3) sustaining a technical capability to support the NASA mission using aging equipment or facilities. It considers (1) program management - key elements of an effective maintainability effort; (2) design and development - techniques that have benefited previous programs; (3) analysis and test - quantitative and qualitative analysis processes and testing techniques; and (4) operations and operational design techniques that address NASA field experience. This document is a valuable resource for continuous improvement ideas in executing the systems development process in accordance with the NASA 'better, faster, smaller, and cheaper' goal without compromising safety. 14. Improving the performance of continuous variable quantum key distribution using fading effects of free-space channel Zhang, Zeyu; Zhu, Chengrui; He, Guangqiang 2015-08-01 Quantum key distribution can be used to share secret keys with information-theoretic security between two legitimate partners for secure communication. In the case of satellite communication, free-space channel is the only way to transmit information, thus research on its properties is of great significance to quantum cryptographic communication. In this paper, we thoroughly analyze the influence of free-space channel fading effects on continuous variable quantum key distribution and for the first time prove that random distribution (such as Rayleigh distribution, Rice distribution and et al.) of free-space channel fading coefficients can be used to increase secret information rates and improve system stability against excess noises. Our results offer academic reference for practical applications of ground-space and space-space quantum communication and global quantum communication network. 15. Mental Health And Its Relation To Academic Achievement. A Brief Note On Auto-suggestion To Improve Mental Health. Anita Chawla 2012-08-01 Full Text Available The main objective of the present study was to test the Mental Health and itsrelation to Academic Achievement. A brief note was added on auto-suggestion toimprove Mental Health. With help of Physiological action of Neurons of Brain,mechanism of auto-suggestion was explained. The participants of the study wereincluded sixty students --- 30 boys and 30 girls -- randomly selected from differentcolleges of Nasik City of age group 21-25 years. Mental Health Inventory by Dr. Jagdishand Dr. Srivastava A.K was used for the purpose of data collection. Second semester(yearly marks of college students were taken. Data analysis was done by usingArithmetic Mean, Standard Deviation, t-test. Findings of the study revealed that femalestudents had better mental health than male students; and mental health score waspositively associated with the academic achievement of the students. 16. Rapid continuous microwave-assisted synthesis of silver nanoparticles to achieve very high productivity and full yield: from mechanistic study to optimal fabrication strategy Dzido, Grzegorz, E-mail: gdzido@polsl.pl [Silesian University of Technology, Department of Chemical Engineering and Process Design, Faculty of Chemistry (Poland); Markowski, Piotr [Silesian University of Technology, Department of Inorganic, Analytical Chemistry and Electrochemistry, Faculty of Chemistry (Poland); Małachowska-Jutsz, Anna [Silesian University of Technology, Department of Environmental Biotechnology, Faculty of Energy and Environmental Engineering (Poland); Prusik, Krystian [University of Silesia, Institute of Materials Science (Poland); Jarzębski, Andrzej B. [Silesian University of Technology, Department of Chemical Engineering and Process Design, Faculty of Chemistry (Poland) 2015-01-15 Systematic studies of silver nanoparticle synthesis in a continuous-flow single-mode microwave reactor using polyol process were performed, revealing that the synthesis is exceptionally effective to give very small metal particles at full reaction yield and very high productivity. Inlet concentration of silver nitrate or silver acetate, applied as metal precursors, varied between 10 and 50 mM, and flow rates ranged from 0.635 to 2.5 dm{sup 3}/h, to give 3–24 s reaction time. Owing to its much higher reactivity, silver acetate was shown to be far superior substrate for the synthesis of small (10–20 nm) spherical silver nanoparticles within a few seconds. Its restricted solubility in ethylene glycol, applied as the solvent and reducing agent, appeared to be vital for effective separation of the stage of particle growth from its nucleation to enable rapid synthesis of small particles in a highly loaded system. This was not possible to obtain using silver nitrate. All the observations could perfectly be explained by a classical LaMer–Dinegar model of NPs’ formation, but taking into account also nonisothermal character of the continuous-flow process and acetate dissolution in the reaction system. The performed studies indicate an optimal strategy for the high-yield fabrication of metal particles using polyol method. 17. Rapid continuous microwave-assisted synthesis of silver nanoparticles to achieve very high productivity and full yield: from mechanistic study to optimal fabrication strategy Systematic studies of silver nanoparticle synthesis in a continuous-flow single-mode microwave reactor using polyol process were performed, revealing that the synthesis is exceptionally effective to give very small metal particles at full reaction yield and very high productivity. Inlet concentration of silver nitrate or silver acetate, applied as metal precursors, varied between 10 and 50 mM, and flow rates ranged from 0.635 to 2.5 dm3/h, to give 3–24 s reaction time. Owing to its much higher reactivity, silver acetate was shown to be far superior substrate for the synthesis of small (10–20 nm) spherical silver nanoparticles within a few seconds. Its restricted solubility in ethylene glycol, applied as the solvent and reducing agent, appeared to be vital for effective separation of the stage of particle growth from its nucleation to enable rapid synthesis of small particles in a highly loaded system. This was not possible to obtain using silver nitrate. All the observations could perfectly be explained by a classical LaMer–Dinegar model of NPs’ formation, but taking into account also nonisothermal character of the continuous-flow process and acetate dissolution in the reaction system. The performed studies indicate an optimal strategy for the high-yield fabrication of metal particles using polyol method 18. How Does School Choice Improve Student Achievement? Estimating School-level Competitive Effects and Student-level Peer Effects Jinnai, Yusuke; 陣内, 悠介 2016-01-01 Although school choice programs have played a key role in public education reform in the United States for years, the impact of competition between schools on student achievement remains unclear. This study examines the effects of introducing charter schools on students at neighboring traditional public schools. Unlike prior work, which estimates the effects of charter schools as a whole, I present that such impact consists of school-level competitive eff ects and student-level peer effects. ... 19. Dominica : OECS Fiscal Issues, Policies to Achieve Fiscal Sustainability and Improve Efficiency and Equity of Public Expenditures World Bank 2005-01-01 This report concludes that during FY1993/94 to FY002/03 the fiscal policy implemented by the government of Dominica was unsustainable and posed a risk to the stability of the currency board arrangement. Moreover, this report recommends that most of the adjustment required to achieve a sustainable fiscal policy needed to come from expenditure cuts, in particular a reduction in the number of established and non-established positions, and from focusing capital expenditures on projects geared to ... 20. Mental Health And Its Relation To Academic Achievement. A Brief Note On Auto-suggestion To Improve Mental Health. Anita Chawla 2012-01-01 The main objective of the present study was to test the Mental Health and itsrelation to Academic Achievement. A brief note was added on auto-suggestion toimprove Mental Health. With help of Physiological action of Neurons of Brain,mechanism of auto-suggestion was explained. The participants of the study wereincluded sixty students --- 30 boys and 30 girls -- randomly selected from differentcolleges of Nasik City of age group 21-25 years. Mental Health Inventory by Dr. Jagdishand Dr. Srivasta... 1. Study on the improved accuracy of strip profile using numerical formula model in continuous cold rolling with 6-high mill The quality requirements for thickness accuracy in cold rolling continue to become more stringent. In cold rolling mill, it is very important that the rolling force calculation considers rolling conditions. The rolled strip thickness was predicted using calculated rolling force. However, the prediction of strip thickness in cold rolling is very difficult; in particular, for 6-high mill with shifted intermediate roll (IMR), the accuracy of thickness is not good. In this study, to improve the accuracy of rolled strip thickness, the roll gap flattening can be given based on Hertz contact theory, with contact between rolls and the smooth cylindrical rolls for the rolling elastic deformation. Also, the distribution of the roll gap flattening may be calculated using the contact force of unit transverse length. The strip profile at the continuous cold rolling is calculated by using the numerical analysis model considering the initial strip profile before cold rolling. Hence, we propose that the numerical model can predict the rolled strip profile more quickly and accurately and be applicable to the field. The results of the proposed numerical model were verified by FE-simulation and cold rolling experiments of 6-high mill with five stands 2. MANUFACTURING AND CONTINUOUS IMPROVEMENT PERFORMANCE LEVEL IN PLANTS OF MEXICO; A COMPARATIVE ANALYSIS AMONG LARGE AND MEDIUM SIZE PLANTS Carlos Monge 2015-12-01 Full Text Available A random and statistically significant sample of 40 medium (12 and large (28 manufacturing plants of Apodaca, Mexico were surveyed using a structured and validated questionnaire to investigate the level of implementation of lean manufacturing, sustainable manufacturing, continuous improvement and operational efficiency and environmental responsibility in them, it is important to mention it was found that performance in the mentioned philosophies, on the two categories of plants is low, however large plants show a better performance than medium plants. In both cases, it is worrying that in the highly industrialized municipality of Apodaca, Mexico are not decisively adopting the philosophies mentioned, as this compromises in a global world, in the medium and long term the viability of the plants, particularly the medium size plants. Finally this article shows the results of the answers to the items of questionnaire for the plants managers, and this can be useful to the management of the plants to identify and to define specific improvement actions towards priority areas. 3. Evaluation and capacity building to improve precollege science and mathematics achievement in the US: 10 CFR, Part 605. Technical progress report, June--December 1992 1992-12-31 The National Center for Improving Science Education has undertaken activities to achieve evaluation goals for DOEs Precollege programs: develop means to determine program quality; develop means for determining the contribution of DOE precollege programs to both teacher enhancement and student achievement; provide evaluation designs and instruments and reports of program quality and impact; and strengthen both DOEs and the Labs` capacity to do both short- and long-term planning as well as deliver effective programs and evaluation. Appendices include evaluation/technical assistance report, profiling teacher research participation and teacher development programs, teacher surveys, impact assessment design, and teacher research participation programs anecdotes for 8 labs. 4. Saint Kitts and Nevis - OECS Fiscal Issues : Policies to Achieve Fiscal Sustainability and Improve Efficiency and Equity of Public Expenditures World Bank 2003-01-01 Despite high levels of per capita incomes and good social service provision, poverty remains a persistent problem in St. Kitts and Nevis. To improve competitiveness, restore rapid economic growth, and ensure its medium-term sustainability in the context of the currency union, the main challenges to the St. Kitts and Nevis government are to (a) tighten fiscal policy, notably through expendi... 5. Technological innovations and design improvements to achieve ALARA exposures in Tarapur Atomic Power Station 3 and 4 (540 MWe) Exposure control at the operating Nuclear Power Station is a major concern. Tarapur Atomic Power Station(TAPS) Unit- 3 and 4 is the first Pressurized Heavy Water Reactor of 540 MWe electrical capacity in-depth review of radiation safety was done to identify the impact of design modification on dose rates. Based on the experience gained in the operation of 220 MWe design modifications incorporated in TAPS unit-3 and 4. The challenging task of meeting the International standards in the field of radiation protection had been achieved at Tarapur Atomic Power Station 3 and 4 right from the initial stages of commissioning and operation. To avoid any unplanned exposures and also to keep the exposures at low level, several innovative features were introduced. These efforts were useful in achieving the lowest collective dose in the first year of operation among the Indian Nuclear Power Plants. This paper presents the brief descriptions of the systems and communication strategies adopted and design modifications implemented to reduce the dose rates and controlling exposure at TAPS 3 and 4. (author) 6. Animation-Based Teaching of Semiconductor Devices: Long-Term Improvement in Students’ Achievements in a Two-Year College Aharon Gero 2015-02-01 Full Text Available The structure and operating principle of semiconductor devices are a central topic in teaching electronics, both in universities and in two-year colleges. Teachers teaching this subject normally run into substantial difficulties stemming from the fact that a major part of the concepts and processes that are relevant to understanding these devices are abstract. In light of the advantages of multimedia in illustrating dynamic processes, the chapter covering the field effect transistor (FET has recently been taught through animation at a two-year college in Israel. The study presented here has examined, through quantitative tools, whether animation-based teaching of the FET had any effect on students’ achievements in the subject of basic electronic devices. Forty electronics students have participated in the study. Its findings indicate that in the short and long term alike, the achievements of students who studied the transistor through animation were significantly higher than those of their peers who studied it through a traditional method. Additionally, the effect size was very large. 7. Monitoring Hip and Elbow Dysplasia achieved modest genetic improvement of 74 dog breeds over 40 years in USA. Yali Hou Full Text Available Hip (HD and Elbow Dysplasia (ED are two common complex developmental disorders of dogs. In order to decrease their prevalence and severity, the Orthopedic Foundation for Animals (OFA has a voluntary registry of canine hip and elbow conformation certified by boarded radiologists. However, the voluntarily reports have been severely biased against exposing dogs with problems, especially at beginning period. Fluctuated by additional influential factors such as age, the published raw scores barely showed trends of improvement. In this study, we used multiple-trait mixed model to simultaneously adjust these factors and incorporate pedigree to derive Estimated Breeding Values (EBV. A total of 1,264,422 dogs from 74 breeds were evaluated for EBVs from 760,455 hip scores and 135,409 elbow scores. These EBVs have substantially recovered the reporting bias and the other influences. Clear and steady trends of genetic improvement were observed over the 40 years since 1970. The total genetic improvements were 16.4% and 1.1% of the phenotypic standard deviation for HD and ED, respectively. The incidences of dysplasia were 0.83% and 2.08%, and the heritabilities were estimated as 0.22 and 0.17 for hip and elbow scores, respectively. The genetic correlation between them was 0.12. We conclude that EBV is more effective than reporting raw phenotype. The weak genetic correlation suggested that selection based on hip scores would also slightly improve elbow scores but it is necessary to allocate effort toward improvement of elbow scores alone. 8. Monitoring Hip and Elbow Dysplasia achieved modest genetic improvement of 74 dog breeds over 40 years in USA. Hou, Yali; Wang, Yachun; Lu, Xuemei; Zhang, Xu; Zhao, Qian; Todhunter, Rory J; Zhang, Zhiwu 2013-01-01 Hip (HD) and Elbow Dysplasia (ED) are two common complex developmental disorders of dogs. In order to decrease their prevalence and severity, the Orthopedic Foundation for Animals (OFA) has a voluntary registry of canine hip and elbow conformation certified by boarded radiologists. However, the voluntarily reports have been severely biased against exposing dogs with problems, especially at beginning period. Fluctuated by additional influential factors such as age, the published raw scores barely showed trends of improvement. In this study, we used multiple-trait mixed model to simultaneously adjust these factors and incorporate pedigree to derive Estimated Breeding Values (EBV). A total of 1,264,422 dogs from 74 breeds were evaluated for EBVs from 760,455 hip scores and 135,409 elbow scores. These EBVs have substantially recovered the reporting bias and the other influences. Clear and steady trends of genetic improvement were observed over the 40 years since 1970. The total genetic improvements were 16.4% and 1.1% of the phenotypic standard deviation for HD and ED, respectively. The incidences of dysplasia were 0.83% and 2.08%, and the heritabilities were estimated as 0.22 and 0.17 for hip and elbow scores, respectively. The genetic correlation between them was 0.12. We conclude that EBV is more effective than reporting raw phenotype. The weak genetic correlation suggested that selection based on hip scores would also slightly improve elbow scores but it is necessary to allocate effort toward improvement of elbow scores alone. PMID:24124555 9. Improving educational achievement and anaemia of school children: design of a cluster randomised trial of school-based malaria prevention and enhanced literacy instruction in Kenya Halliday Katherine E 2010-10-01 Full Text Available Abstract Background Improving the health of school-aged children can yield substantial benefits for cognitive development and educational achievement. However, there is limited experimental evidence on the benefits of school-based malaria prevention or how health interventions interact with other efforts to improve education quality. This study aims to evaluate the impact of school-based malaria prevention and enhanced literacy instruction on the health and educational achievement of school children in Kenya. Design A factorial, cluster randomised trial is being implemented in 101 government primary schools on the coast of Kenya. The interventions are (i intermittent screening and treatment of malaria in schools by public health workers and (ii training workshops and support for teachers to promote explicit and systematic literacy instruction. Schools are randomised to one of four groups: receiving either (i the malaria intervention alone; (ii the literacy intervention alone; (iii both interventions combined; or (iv control group where neither intervention is implemented. Children from classes 1 and 5 are randomly selected and followed up for 24 months. The primary outcomes are educational achievement and anaemia, the hypothesised mediating variables through which education is affected. Secondary outcomes include malaria parasitaemia, school attendance and school performance. A nested process evaluation, using semi-structured interviews, focus group discussion and a stakeholder analysis will investigate the community acceptability, feasibility and cost-effectiveness of the interventions. Discussion Across Africa, governments are committed to improve health and education of school-aged children, but seek clear policy and technical guidance as to the optimal approach to address malaria and improved literacy. This evaluation will be one of the first to simultaneously evaluate the impact of health and education interventions in the improvement of 10. Improving the Image Quality of Synthetic Transmit Aperture Ultrasound Images - Achieving Real-Time In-Vivo Imaging Gammelmark, Kim 2004-01-01 issues need to solved. The goal of this PhD study has been to find methods that can be used to overcome the above mentioned limitations, and hereby improve the image quality of STA imaging to a clinically desirable level, enabling real-time in-vivo STA imaging. The thesis investigates a new method to....... The thesis contains summaries of four journal articles and four corresponding conference publications, which comprise the primary contributions of the PhD. The first two papers give elaborated evaluations of TMS imaging for linear array and convex array imaging, respectively. The results, including...... presented in the third paper, based on a clinical trial with 7 healthy male volunteers. Real-time movie sequences of 3 seconds duration were acquired and analyzed by experienced medical doctors using blinded clinical evaluation. The results showed a statistically significant improvement in image quality of... 11. Child abuse and neglect in Turkey: professional, governmental and non-governmental achievements in improving the national child protection system. Akco, Seda; Dagli, Tolga; Inanici, Mehmet Akif; Kaynak, Hatice; Oral, Resmiye; Sahin, Figen; Sofuoglu, Zeynep; Ulukol, Betul 2013-11-01 Since ratification of the United Nations Convention on the Rights of the Child in 1995, significant efforts were made in Turkey to improve protection of children from abuse and neglect. The government took steps to amend relevant laws. Several state departments recognized the need for professional in-service training of relevant governmental agency staff. University hospitals established numerous hospital-based multidisciplinary child protection centres. The government established an Interministerial Higher Council, which has been overseeing the foundation of 13 child advocacy centres for a multidisciplinary and interagency response to child sexual abuse. In addition to undertaking research, non-governmental organizations contributed to this process by instituting professional and public education. These ground-breaking developments in the last decade give promise of even further improvement in the national child protection system from investigative, child protective and rehabilitative perspectives. PMID:24070409 12. Global health partnerships: building multi-national collaborations to achieve lasting improvements in maternal and neonatal health Ramaswamy, Rohit; Kallam, Brianne; Kopic, Dragica; Pujic, Borislava; Owen, Medge D. 2016-01-01 Background In response to health care challenges worldwide, extensive funding has been channeled to the world’s most vulnerable health systems. Funding alone is not sufficient to address the complex issues and challenges plaguing these health systems. To see lasting improvement in maternal and infant health outcomes in the developing world, a global commitment to the sharing of knowledge and resources through international partnerships is critical. But partnerships that merely introduce weste... 13. An improved anti-leukemic effect achieved with donor progenitor cell infusion for relapse patients after allogeneic bone marrow transplantation 黄晓军; 郭乃榄; 任汉云; 张耀臣; 高志勇; 陆道培 2003-01-01 Objective To observe the antileukemic effect in relapse patients by infusion of donor immunocompetent cells with or without granulocyte colony-stimulating factor (G-CSF) mobilization.Methods Twenty patients with leukemia in relapse after allogeneic bone marrow transplantation (allo-BMT) were treated with chemotherapy followed by donor-derived lymphocytes (DDL) without G-CSF mobilization (Group A, n=11), or donor peripheral blood progenitor cells (PBPCs) with G-CSF mobilization (Group B, n=9).Results Five patients in Group A were in hematologic relapse. After DDL infusion, 3 of 5 patients had a temporary complete remission (CR) and relapsed after 3, 7 and 10 months, respectively. One achieved partial remission and died of interstitial pneumonia; and the other one showed no response. Another 6 patients in Group A were in cytogenetic relapse or central nerve system (CNS) leukemia, and all achieved CR and remained in disease free survival (DFS) for 10 to 98 months after DDL infusion. All 9 patients in group B were in hematologic relapse. Three patients with chronic myeloid leukemia (CML) had cytogenetic and molecular remission for 16, 35 and 51 months, respectively after PBPC infusion; and 5 patients with acute lymphoid leukemia (ALL) had CR and were still in CR for 10 to 18 months except 1 patient relapsed soon. And the other one with AML showed no response to the therapy.Conclusion Donor immunocompetent cells infusion is an effective therapy for relapsed leukemia after allo-BMT, especially for the patients with early (molecular and cytogenetic) or CNS relapse. Infusion of donor PBPC mobilized by G-CSF seems to have more potentiated graft-versus-leukemia (GVL) effect than DDL infusion. 14. Sensitivity improvement of an electrical sensor achieved by control of biomolecules based on the negative dielectrophoretic force. Kim, Hye Jin; Kim, Jinsik; Yoo, Yong Kyoung; Lee, Jeong Hoon; Park, Jung Ho; Hwang, Kyo Seon 2016-11-15 Effective control of nano-scale biomolecules can enhance the sensitivity and limit of detection of an interdigitated microelectrode (IME) sensor. Manipulation of the biomolecules by dielectrophoresis (DEP), especially the negative DEP (nDEP) force, so that they are trapped between electrodes (sensing regions) was predicted to increase the binding efficiency of the antibody and target molecules, leading to a more effective reaction. To prove this concept, amyloid beta 42 (Aβ42) and prostate specific antigen (PSA) protein were respectively trapped between the sensing region owing to the nDEP force under 5V and 0.05V, which was verified with COMSOL simulation. Using the simulation value, the resistance change (ΔR/Rb) of the IME sensor from the specific antibody-antigen reaction of the two biomolecules and the change in fluorescence intensity were compared in the reference (pDEP) and nDEP conditions. The ΔR/Rb value improved by about 2-fold and 1.66-fold with nDEP compared to the reference condition with various protein concentrations, and these increases were confirmed with fluorescence imaging. Overall, nDEP enhanced the detection sensitivity for Aβ42 and PSA by 128% and 258%, respectively, and the limit of detection improved by up to 2-orders of magnitude. These results prove that DEP can improve the biosensor's performance. PMID:27449966 15. Can Community and School-Based Supports Improve the Achievement of First-Generation Immigrant Children Attending High-Poverty Schools? Dearing, Eric; Walsh, Mary E; Sibley, Erin; Lee-St John, Terry; Foley, Claire; Raczek, Anastacia E 2016-05-01 Using a quasi-experimental design, the effects of a student support intervention were estimated for the math and reading achievement of first-generation immigrant children (n = 667, M = 11.05 years of age) attending high-poverty, urban elementary schools. The intervention was designed to help schools identify developmental strengths and barriers to learning and, in turn, connect children to community and school supports aligned with their strengths and needs. By exploiting within-school changes in the implementation of the intervention, the present study revealed statistically and practically significant treatment effects indicating improvements in math and reading achievement at the end of elementary school. In addition, the intervention appears to considerably narrow achievement gaps between English language learners and immigrant children proficient in English. PMID:27028490 16. The Use of Silent Reading in Improving Students’ Reading Comprehension and Their Achievement in TOEFL Score at a Private English Course Hapid Ali 2012-07-01 Full Text Available The purpose of the study is to analyze the use of silent reading in improving students’ reading comprehension and their achievement in TOEFL Score at a Private English Course. The methodology used in the study is quantitative model of analysis base by using inferential statistics analysis; the measurement of correlation coefficient and t-test. The respondents used are students of Private English Course, and the sampling technique used is random stratified sampling with 55 people as the respondents. The result of the research shows that the use of silent reading has a significant and positive influence toward improving students’ reading comprehension and their achievement in TOEFL Score on the study object. 17. Achieving equity in HIV-treatment outcomes: can social protection improve adolescent ART-adherence in South Africa? Cluver, L D; Toska, E; Orkin, F M; Meinck, F; Hodes, R; Yakubovich, A R; Sherr, L 2016-03-01 Low ART-adherence amongst adolescents is associated with morbidity, mortality and onward HIV transmission. Reviews find no effective adolescent adherence-promoting interventions. Social protection has demonstrated benefits for adolescents, and could potentially improve ART-adherence. This study examines associations of 10 social protection provisions with adherence in a large community-based sample of HIV-positive adolescents. All 10-19-year-olds ever ART-initiated in 53 government healthcare facilities in a health district of South Africa's Eastern Cape were traced and interviewed in 2014-2015 (n = 1175 eligible). About 90% of the eligible sample was included (n = 1059). Social protection provisions were "cash/cash in kind": government cash transfers, food security, school fees/materials, school feeding, clothing; and "care": HIV support group, sports groups, choir/art groups, positive parenting and parental supervision/monitoring. Analyses used multivariate regression, interaction and marginal effects models in SPSS and STATA, controlling for socio-demographic, HIV and healthcare-related covariates. Findings showed 36% self-reported past-week ART non-adherence (75 copies/ml) (aOR 1.98, CI 1.1-3.45). Independent of covariates, three social protection provisions were associated with reduced non-adherence: food provision (aOR .57, CI .42-.76, p benefits. With no social protection, non-adherence was 54%, with any one protection 39-41%, with any two social protections, 27-28% and with all three social protections, 18%. These results demonstrate that social protection provisions, particularly combinations of "cash plus care", may improve adolescent adherence. Through this they have potential to improve survival and wellbeing, to prevent HIV transmission, and to advance treatment equity for HIV-positive adolescents. PMID:27392002 18. The Use of Silent Reading in Improving Students’ Reading Comprehension and Their Achievement in TOEFL Score at a Private English Course Hapid Ali 2012-01-01 The purpose of the study is to analyze the use of silent reading in improving students’ reading comprehension and their achievement in TOEFL Score at a Private English Course. The methodology used in the study is quantitative model of analysis base by using inferential statistics analysis; the measurement of correlation coefficient and t-test. The respondents used are students of Private English Course, and the sampling technique used is random stratified sampling with 55 people as the respo... 19. Continuous positive airway pressure therapy is associated with improvement in overactive bladder symptoms in women with obstructive sleep apnea syndrome Ipekci, Tumay; Cetintas, Gulgun; Celik, Orcun; Sarac, Sema; Tunckiran, Ahmet; Ilbey, Yusuf Ozlem 2016-01-01 Introduction To evaluate the impact of continuous positive airway pressure (CPAP) therapy on overactive bladder (OAB) symptoms in women with obstructive sleep apnea syndrome (OSAS). Material and methods One-hundred and fifty women underwent an overnight polysomnography study between May 2014 and September 2014. Their voiding symptoms were evaluated using the OAB symptom score (OABSS) and International Consultation on Incontinence Questionnaire Short-Form at OSAS diagnosis and approximately 3-months after CPAP therapy. OSAS severity was assessed according to the apnea-hypopnea-index. Results We evaluated 140 women and 111 of them (79.3%) reported symptoms consistent with OAB. There were no statistically significant differences between OSAS severity with a prevalence of OAB (p = 0.92). The prevalence of urinary incontinence (UI) was 35.7% (n = 50) and 39.6% (n = 44) in all patients and patients with OAB, respectively. There were no statistically significant differences between UI with OAB (p = 0.58). Baseline OABSS is comparable between OSAS severity (p = 0.143). After 3-months CPAP therapy, OABSS and ICIQ-SF sum scores were significantly decreased in patients with severe and moderate OSAS (p <0.01), however, change of OABSS sum score was insignificant in patients with mild OSAS (p = 0.44). Conclusions CPAP therapy improves the OAB, OABSS and ICIQ-SF scores in women with severe and moderate OSAS. OSAS-induced OAB may be alleviated following CPAP therapy. PMID:27123331 20. Beyond Effectiveness: A Pragmatic Evaluation Framework for Learning and Continuous Quality Improvement of e-Learning Interventions in Healthcare. Dafalla, Tarig Dafalla Mohamed; Kushniruk, Andre W; Borycki, Elizabeth M 2015-01-01 A pragmatic evaluation framework for evaluating the usability and usefulness of an e-learning intervention for a patient clinical information scheduling system is presented in this paper. The framework was conceptualized based on two different but related concepts (usability and usefulness) and selection of appropriate and valid methods of data collection and analysis that included: (1) Low-Cost Rapid Usability Engineering (LCRUE), (2) Cognitive Task Analysis (CTA), (3) Heuristic Evaluation (HE) criteria for web-based learning, and (4) Software Usability Measurement Inventory (SUMI). The results of the analysis showed some areas where usability that were related to General Interface Usability (GIU), instructional design and content was problematic; some of which might account for the poorly rated aspects of usability when subjectively measured. This paper shows that using a pragmatic framework can be a useful way, not only for measuring the usability and usefulness, but also for providing a practical objective evidences for learning and continuous quality improvement of e-learning systems. The findings should be of interest to educators, developers, designers, researchers, and usability practitioners involved in the development of e-learning systems in healthcare. This framework could be an appropriate method for assessing the usability, usefulness and safety of health information systems both in the laboratory and in the clinical context. PMID:25676959 1. Investigations of Techniques to Improve Continuous Air Monitors Under Conditions of High Dust Loading in Environmental Settings A number of DOE facilities, such as the Los Alamos National Laboratory (LANL) and the Waste Isolation Pilot Plant (WIPP), use alpha-particle environmental continuous air monitors (ECAMs) to monitor air for unwanted releases of radioactive aerosols containing such materials as plutonium and uranium. High sensitivity, ease of operation, and lack of false alarms are all important for ECAMs. The object of the project was to conduct investigations to improve operation of ECAMs, particularly under conditions where a lot of nonradioactive dust may be deposited on the filters (conditions of high dust loading). The presence of such dust may increase the frequency with which filters must be changed and can lead to an increased incidence of false alarms due to deteriorated energy resolution and response specificity to the radionuclides of interest. A major finding of the investigation, not previously documented, was that under many conditions thick layers of underlying nonradioactive dust do not decrease energy resolution and specificity for target radionuclides if the radioactive aerosol arrives as a sudden thin burst deposit, as commonly occurs in the early-warning alarm mode. As a result, operators of ECAMs may not need to change filters as often as previously thought and have data upon which to base more reliable operating procedures 2. Experiences in the continuous improvement of quality assurance of the dosimetry services of SLDC-MD-ININ From 2003 the Secondary Laboratory of Dosimetric Calibration (SLDC) of Metrology Department of Ionizing Radiations (MD), has complemented the Quality Manual of National Institute of Nuclear Research (ININ) according to the standard ISO 9001: 2000. However, due to that the National Center of Metrology of Mexico delegates its functions in the dosimetry and activity area for the field of the ionizing radiations to the ININ: one of the requirements so that the ININ has been designated as -Declared Institute- before the International Office of Weights and Measurements, it is to demonstrate before the Inter-American System of Metrology that the quality system of the SLDC fulfills the standard ISO/IEC 17025: 2005, satisfied this requirement the Inter-American System of Metrology in their meeting of evaluation of quality systems, Ottawa (2007) grants a certification document to the SLDC that guarantees their capacities of calibration measurements for dosimetry services. Concretely, inside the standard activities ISO 9000 with respect to the point 8 on measurement, analysis and improvement the Management of Quality Assurance of ININ carries out at year two interns auditing and every month is given continuation to the non conformities detected in the procedures that support the services of the SLDC for dosimetry with purposes of radiological protection and clinical dosimetry. (Author) 3. Lung recruitment can improve oxygenation in patients ventilated in continuous positive airway pressure/pressure support mode András eLovas 2015-04-01 Full Text Available Background: Recruitment maneuvers are often used in critical care patients with hypoxemic respiratory failure. Although continuous positive airway pressure/pressure support (CPAP/PS ventilation is a frequently used approach, but whether lung recruitment also improves oxygenation in spontaneously breathing patients has not been investigated yet. The primary objective was to analyse the effect of recruitment maneuver on oxygenation in patients ventilated in CPAP/PS mode. Methods: Following baseline measurements PEEP was increased by 5 cmH2O. Recruitment maneuver was applied for 40 seconds with 40 cmH2O of PS. Measurements of the difference in PaO2/FiO2 and airway parameters measured by the ventilator were recorded immediately after recruitment then 15 and 30 minutes later. Thirty patients ventilated in CPAP/PS mode with a PEEP ≥ 5 cmH2O were enrolled in this prospective, observational study if their PaO2/FiO2 ratio was 0.5. Results: Following recruitment maneuver patients were considered as non-responders (NR, n=15 if difference of PaO2/FiO2 < 20 % and responders (R, n=15 if difference of PaO2/FiO2 ≥ 20 %. In the NR-group PaO2/FiO2 decreased non-significantly from baseline: median [interquartile], PaO2/FiO2 = 176 [120-186] vs. after recruitment: 169 [121-182] mmHg, P = .307 while in the R-group there was significant improvement: 139 [117-164] vs. 230 [211-323] mmHg, P = .01. At the same time points dead space to tidal volume ratio (Vds/Vte significantly increased in the NR-group Vds/Vte = 32 [27-37] vs. 36 [25-42] %, P = .013 but no significant change was observed in the R-group: 26 [22-34] vs. 27 [24-33] %, p = .386.Conclusion: Recruitment maneuver improved PaO2/FiO2 ratio by ≥ 20 % in 50 % of patients ventilated in CPAP/PS mode. 4. Coconut (Cocos nucifera L.) genetic improvement in Vanuatu: Overview of research achievements from 1962 to 2002. Part 1: Improvement of the Vanuatu Tall by mass selection Labouisse, Jean-Pierre; Sileye, Tiata; Morin, Jean-Paul; Hamelin, Chantal; Baudouin, Luc; Bourdeix, Roland; Rouziere, André 2004-01-01 From 1962 to 2002, at the Saraoutou research station on the island of Santo in Vanuatu, genetic improvement work was undertaken to increase the productivity of coconut plantations, which, through copra exports, were the country's main wealth in the last century. Beginning with two Vanuatu Tall (VTT) populations collected near the station, four mass selection cycles by open pollination or intercrossing have resulted in Elite Vanuatu Tall populations intended for distribution to farmers. The st... 5. Coconut (Cocos nucifera L.) genetic improvement in Vanuatu: Overview of research achievements from 1962 to 2002. Part 2: Improvement of the Vanuatu Tall by hybridization Labouisse, Jean-Pierre; Sileye, Tiata; Morin, Jean-Paul; Hamelin, Chantal; Baudouin, Luc; Bourdeix, Roland; Rouziere, André 2005-01-01 From 1962 to 2002, at the Saraoutou research station on the island of Santo in Vanuatu, a hybrid creation programme was implemented to improve the productive potential of coconut cultivars. The first stage was to create a collection by introducing around thirty exotic varieties. All those varieties and most of the 60 hybrids created proved to be susceptible to coconut foliar decay, a viral disease transmitted by Myndus taffini and endemic in Vanuatu. Only the Vanuatu Tall populations and two ... 6. The introduction of the personnel dosimetry information system in Greece designed as a relational database and the improvements achieved Dose record keeping is the making and keeping of personnel dose records for radiation workers. It is an essential part of the process of monitoring the exposure of individuals to radiation and shares in the same objectives. The dose record keeping is becoming more and more critical because of the importance of statistical analysis and epidemiological studies in radiation protection, and of the increasing cooperation and exchange of personnel between countries.The GAEC's personnel dosimetry laboratory assures the personnel dosimetry all over the country and keeps the official central dose record.The personnel dosimetry information system had been established in an electronic form on 1989 in Cobol language. Since then appeared various arguments that imposed the change of the data base used. Some of them are: 1. There was no distinction between establishments and their laboratories. 2. The workers did not have a unique code number. consequently, the total dose of a person working in more than one place could not't be estimated. The workers were directly related to their workplace, so if somebody changed his working place he was treated as a new entry, resulting an overestimation of the number of monitored workers introducing an source of errors in the collective and average dose calculations. 3. With the increasing applications of the ionising radiations many types of dosemeters became indispensable e.g. for beta and gamma, for neutrons and for the extremities. Also, the new category of outside workers appeared requesting a special treatment. All these distinctions were not achievable with the previous system. 4. Last years appeared an increasing, interesting in statistical analysis of the personal doses. A program written in Cobol does not't offer many possibilities and has no flexibility for such analysis. The new information system has been rebuilt under the design of a relational database with more possibilities and more flexibility. (authors) 7. Response to Intervention and Continuous School Improvement: Using Data, Vision, and Leadership to Design, Implement, and Evaluate a Schoolwide Prevention System Bernhardt, Victoria L.; Hebert, Connie L. 2011-01-01 Ensure the success of your school and improve the learning of "all" students by implementing Response-to-Intervention (RTI) as part of a continuous school improvement (CSI) process. This book shows you how to get your entire staff working together to design, implement, and evaluate a schoolwide prevention system. With specific examples, CSI expert… 8. General chemistry courses that can affect achievement: An action research study in developing a plan to improve undergraduate chemistry courses Shweikeh, Eman Over the past 50 years, considerable research has been dedicated to chemistry education. In evaluating principal chemistry courses in higher education, educators have noted the learning process for first-year general chemistry courses may be challenging. The current study investigated perceptions of faculty, students and administrators on chemistry education at three institutions in Southern California. Via action research, the study sought to develop a plan to improve student engagement in general chemistry courses. A mixed method was utilized to analyze different perceptions on key factors determining the level of commitment and engagement in general chemistry education. The approach to chemistry learning from both a faculty and student perspective was examined including good practices, experiences and extent of active participation. The research study considered well-known measures of effective education with an emphasis on two key components: educational practices and student behavior. Institutional culture was inclusively assessed where cognitive expectations of chemistry teaching and learning were communicated. First, the extent in which faculty members are utilizing the "Seven Principles for Good Practice in Undergraduate Education" in their instruction was explored. Second, student attitudes and approaches toward chemistry learning were examined. The focus was on investigating student understanding of the learning process and the structure of chemistry knowledge. The seven categories used to measure students' expectations for learning chemistry were: effort, concepts, math link, reality link, outcome, laboratory, and visualization. This analysis represents the views of 16 faculty and 140 students. The results validated the assertion that students need some competencies and skills to tackle the challenges of the chemistry learning process to deeply engage in learning. A mismatch exists between the expectations of students and those of the faculty 9. Achievements of grain legume variety improvement using induced mutation of the IAEA/RAS/5/040 project in Thailand The project aims to form a regional cooperation network of mutation germplasm with emphasis on seed-propagated crops among the member states in Asia and Pacific during 2002-2006. It comprised of two components: the establishment and implementation of mutant multi-location trials and the establishment of mutation germplasm network. Thailand participated two crops, soybean and mungbean, of both components. Significant achievements are summarized. Soybean mutant multi-location trials: two introduced mutants were well adapted in the upper and lower north of Thailand. DT84 from Vietnam produced similar yield and matured 18 days earlier than Chiang Mai 60. Bangsakong from Korea gave 11% greater yield with 12 days earlier than Sukhothai 2. Soybean mutants resistant to Soybean Crinkle Leaf: the disease caused by virus and transmitted by whitefly is a major disease in Thailand. Seed of line CM9238-54-1(ST) was irradiated with 200 gray. Mutant lines were selected under natural field infections and tested in laboratory. Six mutant lines resistant to the disease were finally selected. Soybean mutants with high grain protein: seed of vars Chiang Mai 60, SSRSN19-35-4 and EHP275 was irradiated with 200 gray. Pedigree method of selection was used and grain protein of mutants was analysed. The results of a preliminary trial showed that 32 selected mutant lines gave 0.8, 2.0 and 1.0% higher grain protein than the original parents of 41.8, 40.3 and 41.9%, respectively. Soybean mutants with high seed germination and vigor: seed of Chiang Mai 60, a high yielding variety with poor seed germination and vigor, was irradiated with 100 gray. Pedigree selection method was used in late generations. Accelerated Aging Test was also used to test the seed vigor of the mutant lines. In dry season trial, eight mutant lines had seed germination of 65-75% compared with the parent of 30%. In rainy season, 12 mutant lines had seed germination of 75-89% whereas the parent had only 41%. Mungbean mutant 10. Enhancement of filterability in MBR achieved by improvement of supernatant and floc characteristics via filter aids addition. Ji, Jing; Qiu, Jiangping; Wong, Fook-sin; Li, Yaozhong 2008-08-01 Reduction of membrane fouling in membrane bioreactors (MBR) by addition of three typical filter aids (aluminum sulfate (Al(2)(SO(4))(3)), polymeric ferric sulfate (PFS) and Chitosan) was investigated. The effects of filter aids on membrane pore blocking, gel layer and cake layer resistance were analyzed respectively. Significant improvement of the sustainable filtration was demonstrated in the filter aids added MBRs. The membrane fouling rate of the MBRs operated under 20L/m(2)h flux was in the order of Control MBR (no filter aid added)>Al(2)(SO(4))(3) added MBR>Chitosan added MBR>PFS added MBR. Membrane inner fouling due to pore blocking was analyzed by means of Fourier-transform infrared microscope (FTIR). Compared to the control MBR, significantly low protein and carbohydrate concentrations were measured in the membranes of the filter aids added MBRs, indicating that filter aids could effectively alleviate membrane pore blocking. Gel Permeation Chromatography (GPC) analysis suggested that both the concentration and molecular weight distribution of the macromolecules in supernatant play an important role in gel layer formation and loss of membrane porosity. The reduction of fouling rate in the filter aids added MBRs could be attributed to lower concentration and reduction in molecular weight of macromolecules in supernatant. The specific cake resistance (alpha(c)), mean floc size (d(p)) and fractal dimension of the flocs (df) in the filter aids added MBRs were also investigated. It was demonstrated that alpha(c) decreased with the increase of d(p) and with the decrease of df, which is in consistent with the model prediction. PMID:18694586 11. Topical issues in nuclear installation safety: Continuous improvement of nuclear safety in a changing world. Proceedings of an international conference In 1991, the IAEA organized an International Conference on the Safety of Nuclear Power: Strategy for the Future. Recommendations from that conference prompted actions in subsequent installations worldwide, and included the establishment of the Convention on Nuclear Safety, which entered into force in October 1996. In 1998, the IAEA sponsored an International Conference on Topical Issues in Nuclear, Radiation and Radioactive Waste Safety. In response to the concerns identified and the recommendations provided by the conference, actions were taken to improve the monitoring of safety by developing performance indicators; furthering the use of probabilistic safety insights to complement and help optimize the prescriptive nature of regulations; and addressing actions needed to ensure the future availability of competent professionals. In 2001, the IAEA sponsored an International Conference on Topical Issues in Nuclear Safety. The findings were again essential in providing Member States, the IAEA and the nuclear industry with insights into where future activities should be focused. Some of these areas included the need to develop international guidance on the use of probabilistic safety insights, the potential negative impacts on safety from external factors, the need for emergency preparedness guidance for fuel cycle facilities, the safety challenges associated with poor utilization programmes at research reactors, and the need to develop simple indicators of safe operating performance. Although substantial progress has been made in improving the safe operational performance of nuclear installations over the past years, numerous issues continue to be of concern. These include ensuring quality of design and operation of nuclear installations with the growing diversification and globalization of the nuclear community, obtaining, maintaining and managing knowledge, utilizing common internationally accepted safety standards, balancing the needs between safety and security 12. Continuous and interval training programs using deep water running improves functional fitness and blood pressure in the older adults. Reichert, Thaís; Kanitz, Ana Carolina; Delevatti, Rodrigo Sudatti; Bagatini, Natália Carvalho; Barroso, Bruna Machado; Kruel, Luiz Fernando Martins 2016-02-01 This study aimed to investigate the effects of two periodized training programs of deep water running on functional fitness and blood pressure in the older adults. Thirty-six individuals were divided into continuous group (CONT) and interval group (INT). Both groups were trained for 28 weeks (twice weekly). Measures were performed before the training period, after 12 weeks and training period. Two-way ANOVA and post hoc of Bonferroni were used (α = 0.05). There were no differences between groups in functional tests, with the exception of the flexibility of the upper limbs, in which the INT group showed the highest values. There was a significant improvement in both groups of foot up-and-go test (CONT 6.45 to 5.67; INT 6.59 to 5.78, in seconds), flexibility of lower limbs (CONT -4.76 to -0.61; INT 0.54 to 4.63, in centimeters), strength of upper (CONT 18.76 to 27.69; INT 18.66 to 26.58, in repetitions) and lower limbs (CONT 14.46 to 21.23; INT 14.40 to 21.58, in repetitions), and 6-min walk (CONT 567.50 to 591.16; INT 521.41 to 582.77, in meters). No differences were shown between groups for systolic blood pressure; however, diastolic blood pressure remained higher in CONT during all training. The blood pressure decreased significantly in both groups after the training (CONT 142 ± 16/88 ± 3 to 125 ± 14/77 ± 7 mmHg; INT 133 ± 15/75 ± 7 to 123 ± 17 and 69 ± 11 mmHg). Both programs of deep water running training promoted improvements of similar magnitude in all parameters of functional fitness, with the exception of flexibility of upper limbs, and decreased blood pressure in the older individuals. PMID:26841888 13. Continued improvement in survival of acute myeloid leukemia patients: an application of the loss in expectation of life. Bower, H; Andersson, T M-L; Björkholm, M; Dickman, P W; Lambert, P C; Derolf, Å R 2016-01-01 We evaluated temporal trends in survival of Swedish acute myeloid leukemia (AML) patients diagnosed between 1973 and 2011 using relative survival ratios (RSRs) and a measure called the loss in expectation of life (LEL). RSRs increased most for patients <60 years at diagnosis during the first calendar periods, but between 1997-2005 and 2006-2011 the most pronounced increase was for those aged 61-70 years at diagnosis; RSR changed from 0.16 (95% confidence interval (CI): 0.13-0.19) to 0.28 (95% CI: 0.23-0.33), respectively. The LEL for males aged 35 years at diagnosis was 41.0 (95% CI: 40.1-41.8) years in 1975 and 19.5 (95% CI: 16.4-22.5) years in 2011. For males aged 65 years, the corresponding figures were 13.8 (95% CI: 13.7-14.0) and 12.0 (95% CI: 11.3-12.8). Conditional LEL estimates suggested that patients who survive 5 years postdiagnosis have shorter remaining lifespan than the general population. The proportion of expected life lost (PELL) suggested that male 65-year-old patients lost 75% of their life expectancy in 2005 and 66% if they were diagnosed in 2011. Survival continued to increase to 2011, with larger improvements in those aged 61-70 years at diagnosis. The LEL and PELL are intuitive measures that may be useful in communicating survival statistics to patients, clinicians and health-care providers. PMID:26849011 14. Achievements of Grain Legume Variety Improvement Using Induced Mutation of the IAEA/RAS/5/040 Project in Thailand IAEA/RAS/5/040 project aims to form a regional cooperation network of mutation germplasm with emphasis on seed-propagated crops among the Member States in Asia and Pacific commencing in 2002 and ending in 2006. It comprised of two components, the establishment and implementation of mutant multi-location trials and the establishment of mutation germplasm network. Thailand participated with two major grain legume crops, soybean and mungbean, of both components. Significant achievements are summarized. Soybean mutant multi-location trials: Two introduced mutants, DT84 from Vietnam and Bangsakong from Korea were well adapted in the upper and lower north of Thailand. DT84 produced similar yield and matured 18 days earlier than Chiang Mai 60 whereas Bangsakong gave 11% greater yield with 12 days earlier than Sukhothai. Soybean mutants resistant to Soybean Crinkle Leaf: The disease, caused by virus, is a major disease in Thailand. It is transmitted by whitefly (Bemisia tabaci). Seed of a soybean linecm9238-54-1(ST) was irradiated with 200 gray. A number of mutant lines were selected under natural field infections and tested in laboratory. Six mutant lines resistant to the disease were finally selected. Soybean mutants with high grain protein: The government policy is to increase grain protein soybean for soy food products. Seeds of three soybean varieties namely Chiang Mai 60, SSRSN19-35-4 and EHP275 were irradiated with 200 gray. Pedigree method of selection was used and grain protein of the mutants was analysed. Thirty two mutant lines were selected. The result of a preliminary trial showed that the lines gave average grain protein of 0.8, 2.0 and 1.0% higher than the original parents of 41.8, 40.3 and 41.9%, respectively. Soybean mutants with high seed germination and vigor: Chiang Mai 60, a high yielding soybean variety, has a poor character of seed germination and vigor. Seed of Chiang Mai 60 was irradiated with 100 gray. Pedigree method of selection was used in late 15. IMPROVEMENT OF EXPOSURE-DOSE MODELS: APPLICATION OF CONTINUOUS BREATH SAMPLING TO DETERMINE VOC DOSE AND BODY BURDEN This is a continuation of an Internal Grant research project with the focus on completing the research due to initial funding delays and then analyzing and reporting the research results. This project will employ a new continuous breath sampling methodology to investigate dose a... 16. Longitudinal Numbers-Needed-To-Treat (NNT for Achieving Various Levels of Analgesic Response and Improvement with Etoricoxib, Naproxen, and Placebo in Ankylosing Spondylitis Wang Hongwei 2011-07-01 Full Text Available Abstract Background Clinical analgesic trials typically report response as group mean results. However, research has shown that few patients are average and most have responses at the extremes. Moreover, group mean results do not convey response levels and thus have limited value in representing the benefit-risk at an individual level. Responder analyses and numbers-needed-to-treat (NNT are considered more relevant for evaluating treatment response. We evaluated levels of analgesic response and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI score improvement and the associated NNTs. Methods This was a post-hoc analysis of a 6-week, randomized, double-blind study (N = 387 comparing etoricoxib 90 mg, etoricoxib 120 mg, naproxen 1000 mg, and placebo in AS. Spine pain and BASDAI were measured on a 100-mm visual analog scale. The number and percentage of patients achieving ≥30% and ≥50% improvement in both BASDAI and spine pain were calculated and used to determine the corresponding NNTs. Patients who discontinued from the study for any reason were assigned zero improvement beyond 7 days of the time of discontinuation. Results For etoricoxib 90 mg, etoricoxib 120 mg and naproxen 1000 mg, the NNTs at 6 weeks compared with placebo were 2.0, 2.0, and 2.7 respectively for BASDAI ≥30% improvement, and 3.2, 2.8, and 4.1 for ≥50% improvement. For spine pain, the NNTs were 1.9, 2.0, and 3.2, respectively, for ≥30% improvement, and 2.7, 2.5, and 3.7 for ≥50% improvement. The differences between etoricoxib and naproxen exceeded the limit of ±0.5 units described as a clinically meaningful difference for pain. Response rates and NNTs were generally similar and stable over 2, 4, and 6 weeks. Conclusions For every 2 patients treated with etoricoxib, 1 achieved a clinically meaningful (≥30% improvement in spine pain and BASDAI beyond that expected from placebo, whereas the corresponding values were approximately 1 in every 3 patients 17. Improving the Quality of the Pharmacist as a Drug Advisor to Patients and Physicians Through Continuing Education Watkins, Roland L.; And Others 1976-01-01 A continuing education program was successful in changing both the knowledge and behavior of an experimental group of pharmacists. Their attitudes were not significantly changed, and this might be explained through cognitive dissonance theory. (LBH) 18. The Power to drive change: Working together for excellence. Creating a continuously improving consumer engagement framework for excellence in patient-centered care. Ryan, Catherine 2016-01-01 The World Health Organization has acknowledged Patient Safety while receiving hospital care as a serious global public health issue, with patient empowerment and community engagement key to continuously improving safety and quality of care for the best possible clinical and patient outcomes. In Australia, the introduction of ten mandatory National Safety and Quality Health Service Standards in 2011 provided the catalyst for all Australian health facilities to review their systems. Standard 2: Partnering with Consumers required health facilities across Australia to assess commitment to, and capacity for consumer and community engagement and participation. At this time, the Royal Brisbane and Women's Hospital did not have a strategic perspective and understanding, or an organizational structure for engaging with consumers (patients, families, care givers and community members). The concept required a new model to replace the clinician-led model of healthcare historically featured in Australia, with a change in culture and core business. processes to partner with consumers at all levels of the system, from individual patient care through to participating in policy development, health service planning and delivery, and evaluation and measurement processes. The challenge for the hospital was to build a sustainable framework of engagement for a genuine patient-centered model of care informed by best practice, and provide leadership and commitment to developing as an area of excellence in patient engagement and experience. A successful and sustainable framework for consumer and community engagement has been embedded in the hospital, with resultant culture change, achieving accreditation across all core and developmental criteria for the partnering with consumer standards including several Met with Merit ratings. PMID:27180474 19. Knowledge management in R&D centres, in the field of biomedicine, using contemporary information and communication technology and the methodology of continuous improvement Ryszard Depta 2015-09-01 Full Text Available Some sophisticated medical applications, including advanced therapeutics with monoclonal antibodies, stem cells, and gene therapies are currently available in clinical trials. More revolutionary technologies are coming soon and will be marketed by the best technically advanced companies in the world. R&D companies with a much smaller indicator of technological progress and organizational efficiency, but with a great desire to become a major player in this industry, will also compete for a share of this market. However, in order to become a fixture in the changes initiated, both must constantly learn and be more innovative. In the current market situation, a hypercompetitive economy with the entrepreneurs’ focus on the prosumer, creativity is becoming extremely important in achieving final success. Creativity, which is the result of proper knowledge management, especially in science. The market value of R&D companies and their further future depends to a large extent on the prosperity of knowledge transfer. The most important role in the process of knowledge transfer is played by information and communication technologies (ICT and tools for continuous improvement. If companies implement these efficiently and safely, they can develop and benefit from competitive advantages for a very long period of time. Such an approach would give them the possibility of reducing the cost and time to deliver new products to market, and create a new platform to generate innovative products. This is a new perspective for R&D businesses, and a great opportunity for institutions in the biomedical arena to become part of the upcoming bio-revolution. 20. Does Homework Really Improve Achievement? Costley, Kevin C. 2013-01-01 Should public school teachers assign daily homework? Should school districts have policies requiring teachers to assign homework? Is homework beneficial to students? Do students learn from completing daily homework? In this article, a review of literature is included offering pros and cons to students doing homework with various counterpoint… 1. Teaching Triarchically Improves School Achievement. Sternberg, Robert J.; Torff, Bruce; Grigorenko, Elena L. 1998-01-01 Two studies involving 213 third graders and 141 eighth graders tested the triarchic structure of human intelligence as applied to the classroom by emphasizing traditional instruction, critical thinking, and triarchically based instruction (analytical, creative, and practical). Results support the superiority of triarchically-based instruction.… 2. Continuing education for maternal child health nurses: a means to improve the health care of mothers and children. Bolte, I M; Presler, E P 1983-01-01 The University of Kentucky College of Nursing is in the 7th year of implementing a 7-year federally funded continuing education project. The major goal of MCH (maternal child health) Project 969, which is scheduled to terminate Sept. 30, 1984, is to develop and offer a series of quality continuing education courses for three distinct populations--practicing maternal child health nurses, State nurse consultants, and nurse supervisors at county or district levels. The purpose of these courses i... 3. Effectiveness of music education for the improvement of reading skills and academic achievement in young poor readers: a pragmatic cluster-randomized, controlled clinical trial. Hugo Cogo-Moreira Full Text Available INTRODUCTION: Difficulties in word-level reading skills are prevalent in Brazilian schools and may deter children from gaining the knowledge obtained through reading and academic achievement. Music education has emerged as a potential method to improve reading skills because due to a common neurobiological substratum. OBJECTIVE: To evaluate the effectiveness of music education for the improvement of reading skills and academic achievement among children (eight to 10 years of age with reading difficulties. METHOD: 235 children with reading difficulties in 10 schools participated in a five-month, randomized clinical trial in cluster (RCT in an impoverished zone within the city of São Paulo to test the effects of music education intervention while assessing reading skills and academic achievement during the school year. Five schools were chosen randomly to incorporate music classes (n = 114, and five served as controls (n = 121. Two different methods of analysis were used to evaluate the effectiveness of the intervention: The standard method was intention-to-treat (ITT, and the other was the Complier Average Causal Effect (CACE estimation method, which took compliance status into account. RESULTS: The ITT analyses were not very promising; only one marginal effect existed for the rate of correct real words read per minute. Indeed, considering ITT, improvements were observed in the secondary outcomes (slope of Portuguese = 0.21 [p<0.001] and slope of math = 0.25 [p<0.001]. As for CACE estimation (i.e., complier children versus non-complier children, more promising effects were observed in terms of the rate of correct words read per minute [β = 13.98, p<0.001] and phonological awareness [β = 19.72, p<0.001] as well as secondary outcomes (academic achievement in Portuguese [β = 0.77, p<0.0001] and math [β = 0.49, p<0.001] throughout the school year. CONCLUSION: The results may be seen as promising, but they are not 4. Using optimal combination of teaching-learning methods (open book assignment and group tutorials) as revision exercises to improve learning outcome in low achievers in biochemistry. Rajappa, Medha; Bobby, Zachariah; Nandeesha, H; Suryapriya, R; Ragul, Anithasri; Yuvaraj, B; Revathy, G; Priyadarssini, M 2016-07-01 Graduate medical students of India are taught Biochemistry by didactic lectures and they hardly get any opportunity to clarify their doubts and reinforce the concepts which they learn in these lectures. We used a combination of teaching-learning (T-L) methods (open book assignment followed by group tutorials) to study their efficacy in improving the learning outcome. About 143 graduate medical students were classified into low (75%: group 3, n = 46) achievers, based on their internal assessment marks. After the regular teaching module on the topics "Vitamins and Enzymology", all the students attempted an open book assignment without peer consultation. Then all the students participated in group tutorials. The effects on the groups were evaluated by pre and posttests at the end of each phase, with the same set of MCQs. Gain from group tutorials and overall gain was significantly higher in the low achievers, compared to other groups. High and medium achievers obtained more gain from open book assignment, than group tutorials. The overall gain was significantly higher than the gain obtained from open book assignment or group tutorials, in all three groups. All the three groups retained the gain even after 1 week of the exercise. Hence, optimal use of novel T-L methods (open book assignment followed by group tutorials) as revision exercises help in strengthening concepts in Biochemistry in this oft neglected group of low achievers in graduate medical education. © 2016 by The International Union of Biochemistry and Molecular Biology, 44(4):321-325, 2016. PMID:26891594 5. Impacts of continual and periodic disturbances on a Central Amazonian forest: lessons from a gap model for future model improvement Holm, J. A.; Chambers, J. Q.; Collins, W. 2013-12-01 Uncertainties surrounding vegetation and carbon responses to increased disturbance rates associated with climate change remains a major global change issue for Amazon forests. To help quantify the impacts of increased disturbances on climate and the earth system, the fidelity of tree mortality and disturbance algorithms in global land surface models (here the Community Land Model, CLM) warrant critical evaluation. In order to address this issue, we parameterized and calibrated ZELIG-TROP, a dynamic vegetation gap model, to simulate a complex Central Amazon forest toward improving disturbance-recovery processes in CLM. To evaluate the long-term consequences of increased disturbance rates in ZELIG-TROP and CLM for a Central Amazon rainforest, we 1) doubled background tree mortality rates (i.e., high disturbance treatment), and 2) applied a periodic disturbance treatment of removing 20% of stems every 50 years (i.e., periodic treatment) and compared model results. For the high disturbance treatment, ZELIG-TROP predicted that AGB and ANPP decreased by an average of 110 Mg ha-1 and 0.48 Mg C ha-1 yr-1 respectively (41.9% and 7.7%). The net carbon loss due to the periodic treatment, with four large-scale disturbances, was not as extreme as the loss from the high disturbance treatment, due to recovery dynamics. AGB only decreased by 15.9% (vs. 41.9%), however ANPP decreased by 19% (vs. 7.7%). For the high disturbance treatment in ZELIG-TROP, there were a higher proportion of smaller stems and a decrease in larger stems. This resulted in a decrease in coarse litter (trunks and large branches >10 cm in diameter) production rates (Mg C ha-1 yr-1) by 11.5%. For the periodic disturbance the average coarse litter production rates increased by 11.2% due to the four large-scale disturbance events. A comparison of the biomass response of ZELIG-TROP and CLM from simulated disturbance and recovery events displayed the same pattern between the two models, and for both disturbance 6. A Comparative Case Study Analysis of Administrators Perceptions on the Adaptation of Quality and Continuous Improvement Tools to Community Colleges in the State of Michigan Mattis, Ted B. 2011-01-01 The purpose of this study was to determine whether community college administrators in the state of Michigan believe that commonly known quality and continuous improvement tools, prevalent in a manufacturing environment, can be adapted to a community college model. The tools, specifically Six Sigma, benchmarking and process mapping have played a… 7. Turning around, Transforming, and Continuously Improving Schools: Policy Proposals Are Still Based on a Two- Rather than a Three-Component Blueprint Adelman, Howard; Taylor, Linda 2011-01-01 Clearly, low performing, and especially failing schools, are a high priority concern for policy makers. And it is evident that fundamental systemic changes are necessary. The authors contend that it is essential that policy makers move to a three-component framework for turning around, transforming, and continuously improving schools. The third… 8. Evaluating a Program Designed to Demonstrate Continuous Improvement in Teaching at an AACSB-Accredited College of Business at a Regional University: A Case Study Pritchard, Robert E.; Saccucci, Michael S.; Potter, Gregory C. 2010-01-01 This article provides a detailed statistical analysis of a process intended to demonstrate continuous improvement in teaching at an AACSB accredited college of business. The Educational Testing Service's SIR II student evaluation instrument was used to measure teaching effectiveness. A six-year longitudinal analysis of the SIR II results does not… 9. Efficacy of Continuing Education in Improving Pharmacists' Competencies for Providing Weight Management Service: Three-Arm Randomized Controlled Trial Sarayani, Amir; Rashidian, Arash; Gholami, Kheirollah; Torkamandi, Hassan; Javadi, Mohammadreza 2012-01-01 Introduction: Weight management is a new public health role for community pharmacists in many countries. Lack of expertise is one of the key barriers to counseling obese patients. We evaluated the comparative efficacy of three alternative continuing education (CE) meetings on weight management. Methods: We designed a randomized controlled trial… 10. Research on improved design of airfoil profiles based on the continuity of airfoil surface curvature of wind turbines Chen, Jin; Cheng, Jiangtao; Shen, Wenzhong; Zhu, Weijun; Wang, Xudong 2013-01-01 Aerodynamic of airfoil performance is closely related to the continuity of its surface curvature, and airfoil profiles with a better aerodynamic performance plays an important role in the design of wind turbine. The surface curvature distribution along the chord direction and pressure distributio... 11. Continuous parallel coordinates. Heinrich, Julian; Weiskopf, Daniel 2009-01-01 Typical scientific data is represented on a grid with appropriate interpolation or approximation schemes,defined on a continuous domain. The visualization of such data in parallel coordinates may reveal patterns latently contained in the data and thus can improve the understanding of multidimensional relations. In this paper, we adopt the concept of continuous scatterplots for the visualization of spatially continuous input data to derive a density model for parallel coordinates. Based on the point-line duality between scatterplots and parallel coordinates, we propose a mathematical model that maps density from a continuous scatterplot to parallel coordinates and present different algorithms for both numerical and analytical computation of the resulting density field. In addition, we show how the 2-D model can be used to successively construct continuous parallel coordinates with an arbitrary number of dimensions. Since continuous parallel coordinates interpolate data values within grid cells, a scalable and dense visualization is achieved, which will be demonstrated for typical multi-variate scientific data. PMID:19834230 12. 持续质量改进理论在妇幼保健院处方点评中的应用%Application of Continuous Quality Improvement Theory in Prescription Comments in Maternal and Children Health Care Hospital 李艳; 朱华威 2012-01-01 OBJECTIVE: To investigate the application of continuous quality improvement theory in prescription comments in outpatient department of maternal and child health care hospital. METHODS: Based on PDCA cycle method, the outpatient prescriptions were commented in respects of Plan, Do, Check and Action. We conducted continuous quality management, found out the specific performance of the unqualified prescription, analyzed the possible causes, made improvement plan and achieved goal, cleared and defined responsible person. We took a random sample of 1 800 outpatient prescriptions within 9 months after continuous quality improvement (200 prescriptions each month), and calculated the monthly qualified rate of prescription. RESULTS: The qualified rate of outpatient prescriptions had been improved from 55% before quality improvement to 60% , 65% , 85% , 86% , 88%, 90%, 95%, 99% and 99% from Jan. To Sept. After quality improvement (P<0.05). CONCLUSION: Application of continuous quality improvement in the comments of outpatient prescription can effectively improve the quality of outpatient prescription and rational drug use.%目的:探讨持续质量改进理论在妇幼保健院门诊处方点评中的应用.方法:基于PDCA循环法,对门诊处方点评工作采取计划、执行、检查和行动4个阶段的过程管理,通过找出不合格处方的表现、分析原因、制定改进措施及目标、明确责任人进行持续质量改进.随机抽取改进后9个月的门诊处方1800张(每月200张)统计每月处方合格率.结果:门诊处方合格率由改进前的55％提高到改进后1-9月的60％、65％、85％、86％、88％、90％、95％、99％、99％(P＜0.05).结论:在门诊处方点评中引进持续质量改进管理方法,提高了门诊处方的质量,促进了合理用药. 13. Comparative Analysis of Improved Cuckoo Search(ICS) Algorithm and Artificial Bee Colony (ABC) Algorithm on Continuous Optimization Problems Shariba Islam Tusiy; Nasif Shawkat; Md. Arman Ahmed; Biswajit Panday; Nazmus Sakib 2015-01-01 This work is related on two well-known algorithm, Improved Cuckoo Search and Artificial Bee Colony Algorithm which are inspired from nature. Improved Cuckoo Search (ICS) algorithm is based on Lévy flight and behavior of some birds and fruit flies and they have some assumptions and each assumption is highly observed to maintain their characteristics. Besides Artificial Bee Colony (ABC) algorithm is based on swarm intelligence, which is based on bee colony with the way the bees maintain their l... 14. Achievement of Total Quality Is Impossibility Xiaohang Wu; Yafei Wang 2009-01-01 In the manufacturing industry, product quality has become a key factor in determining a firm’s success or failure in the global marketplace. Advanced, highly reliable manufacturing methods have made it possible to achieve very high standards of product quality. As a result, more and more firms are making product quality a keystone of their competitive strategy. However, the improvement of production quality is a long-term commitment to continuous improvement in every aspect of the production ... 15. Observations of human factors as a continuous improvement tool; Las obervaciones de factores humanos como herramienta de mejora continua Almeida, P. 2015-07-01 Principles for Excellence in Human Performance should promote behaviors throughout an organization that support safety and reliable operation of the plant. Such behaviors must be clearly defined, communicated and reinforced by managers, on a continuous basis. To identify if workers behaviors are in compliance with those expected is paramount to have an observations program in place, which in one hand identifies deviations from expectations to correct them, and on the other promotes the desired behaviors through positive reinforcement. (Author) 16. Comparative Analysis of Improved Cuckoo Search(ICS Algorithm and Artificial Bee Colony (ABC Algorithm on Continuous Optimization Problems Shariba Islam Tusiy 2015-02-01 Full Text Available This work is related on two well-known algorithm, Improved Cuckoo Search and Artificial Bee Colony Algorithm which are inspired from nature. Improved Cuckoo Search (ICS algorithm is based on Lévy flight and behavior of some birds and fruit flies and they have some assumptions and each assumption is highly observed to maintain their characteristics. Besides Artificial Bee Colony (ABC algorithm is based on swarm intelligence, which is based on bee colony with the way the bees maintain their life in that colony. Bees’ characteristics are the main part of this algorithm. This is a theoretical result of this topic and a quantitative research paper. 17. A Case Study of Non-Functional Requirements and Continuous Improvement at a National Communications System Contractor Douglas, Volney L. R. 2010-01-01 National communications systems (NCS) are critical elements of a government's infrastructure. Limited improvements to the non-functional requirements (NFR) of NCS have caused issues during national emergencies such as 9/11 and Hurricane Katrina. The literature indicates that these issues result from a deficiency in understanding the roles NFRs and… 18. Continuous improvement of the Quality Management System based on the analysis of the results of self-esteem Tatyana Tymaeva 2015-05-01 Full Text Available The problem of improving the quality management system in educational organization and effectiveness of the participation of school in the regional project "Implementation of the model of quality management system of education in educational institutions of the Novosibirsk region." 19. Improving the maximum transmission distance of continuous-variable quantum key distribution with noisy coherent states using a noiseless amplifier By employing a nondeterministic noiseless linear amplifier, we propose to increase the maximum transmission distance of continuous-variable quantum key distribution with noisy coherent states. With the covariance matrix transformation, the expression of secret key rate under reverse reconciliation is derived against collective entangling cloner attacks. We show that the noiseless linear amplifier can compensate the detrimental effect of the preparation noise with an enhancement of the maximum transmission distance and the noise resistance. - Highlights: • Noiseless amplifier is applied in noisy coherent state quantum key distribution. • Negative effect of preparation noise is compensated by noiseless amplification. • Maximum transmission distance and noise resistance are both enhanced 20. Improving the teaching and learning of science in a suburban junior high school on Long Island: Achieving parity through cogenerative dialogues Baker, Eileen Perman The research in this dissertation focuses on ways to improve the teaching and learning of science in a suburban junior high school on Long Island, New York. The study is my attempt to find ways to achieve parity in my classroom in terms of success in science. I was specifically looking for ways to encourage Black female students in my classroom and in other classrooms to continue their science education into the upper grades. The participants were the 27 students in the class, a friend of one of the students, and I, as the teacher-researcher. In order to examine the ways in which structure mediates the social and historical contexts of experiences in relation to teacher and student practices in the classroom, I used collaborative research; autobiographical reflection; the sociology of emotions; immigration, racialization, and ethnicity, and cogenerative dialogues (cogens) as tools. Cogenerative dialogues are a way for students and teachers to accept shared responsibility for teaching and learning. This study is of importance because of my school's very diverse student body. The school has a large minority population and therefore shares many of the characteristics of urban schools. In my study I look at why there are so few Black female students in the advanced science courses offered by our district and how this problem can be addressed. I used a variety of qualitative approaches including critical ethnography and micro analysis to study the teaching and learning of science. In addition to the usual observational, methodological, and theoretical field notes, I videotaped and audiotaped lessons and had discussions with students and teachers, one-on-one and in groups. In the first year the cogenerative group consisted of two Black female students. In the second year of the study there were four Black and one White-Hispanic female students in the cogen group. In my research I studied the interactions of the students between lessons and during laboratory activities as 1. Client incentives versus contracting and staff incentives: how care continuity interventions in substance abuse treatment can improve residential to outpatient transition. Acquavita, Shauna P; Stershic, Sandra; Sharma, Rajni; Stitzer, Maxine 2013-07-01 Interventions for improving transition from short-term residential to outpatient treatment were examined. Usual care (UC; n=114) was referral to a preferred outpatient program with advance appointment optional. Client incentive (CI; n=97) offered up to100 in gift cards for intake and attendance during the first 30days of treatment. Contracting with staff incentives (CSI; n=49) consisted of meeting with an outpatient counselor prior to residential discharge, signing an attendance contract, receiving an appointment and payment to staff if clients attended. CSI significantly improved rates of successful transition (84%) and admission (74%) compared to UC (64% contact; 49% admitted). CI did not result in significantly improved outcomes (74%; 60%). CSI was likely mediated by the reliability (92 versus 52% in UC) and immediacy (1.0 versus 3.9days) of appointment scheduling. This study supports use of CSI for improving rates of transition between residential and outpatient continuing care treatment. PMID:23375361
2. Continuous improvement of high-efficiency high-power 800-980nm diode lasers at Spectra-Physics
Li, Hanxuan; Towe, Terry; Chyr, Irving; Jin, Xu; Miller, Robert; Romero, Oscar; Liu, Daming; Brown, Denny; Truchan, Tom; Nguyen, Touyen; Crum, Trevor; Wolak, Ed; Bullock, Robert; Mott, Jeff; Harrison, James
2009-02-01
New-generation multi-mode 9xx mini-bars used in fiber pump modules have been developed. The epitaxial designs have been improved for lower fast-axis and slow-axis divergence, higher slope efficiency and PCE by optimizing layer structures as well as minimizing internal loss. For 915nm mini-bars with 5-mm cavity length, maximum PCE is as high as ~61% for 35W operation and remains above 59% at 45W. For 808nm, a PCE of 56% at 135W CW operation has been demonstrated with 36%-fill-factor, 3-mm-cavity-length, water-cooled bars at 50°C coolant temperature. On passive-cooled standard CS heatsinks, PCE of >51% is measured for 100W operation at 50°C heatsink temperature. Leveraging these improvements has enabled low-cost bars for high-power, high-temperature applications.
3. Improved compression molding technology for continuous fiber reinforced composite laminates. Part 2: AS-4/Polyimidesulfone prepreg system
Baucom, Robert M.; Hou, Tan-Hung; Kidder, Paul W.; Reddy, Rakasi M.
1991-01-01
AS-4/polyimidesulfone (PISO2) composite prepreg was utilized for the improved compression molding technology investigation. This improved technique employed molding stops which advantageously facilitate the escape of volatile by-products during the B-stage curing step, and effectively minimize the neutralization of the consolidating pressure by intimate interply fiber-fiber contact within the laminate in the subsequent molding cycle. Without the modifying the resin matrix properties, composite panels with both unidirectional and angled plies with outstanding C-scans and mechanical properties were successfully molded using moderate molding conditions, i.e., 660 F and 500 psi, using this technique. The size of the panels molded were up to 6.00 x 6.00 x 0.07 in. A consolidation theory was proposed for the understanding and advancement of the processing science. Processing parameters such as vacuum, pressure cycle design, prepreg quality, etc. were explored.
4. STANDPOINT OF THE TOP MANAGEMENT ABOUT THE EFFECTS OF INTRODUCED QUALITY SYSTEM AND CONTINUATION AF ACTIVITIES OF ITS IMPROVEMENT
Sabahudin Jasarevic
2015-06-01
Full Text Available There are number of obstacles on a challenging road to the effectiveness and business and organizational excellence. One of the most difficult ones is human (not understanding of the constant flux of change. Such is the case when it comes to development of quality management system. Will the quality be either a problem or resource of some organization depends above all on the basic standpoint towards quality that exists in the organization. Many authors underline that implementation of quality management system and obtaining ISO 9000 certificate is not an easy task, but also emphasize that its maintenance and improvement is much more difficult task. The greatest number of problems that occur during the realization of project of quality management system as well as its improvement are the result of misunderstanding of the essence of standard, that is its principles. On of these principles is Leadership too, that is the role of Top Management. Managers at the highest levels are certainly the most responsible for establishing the vision and guiding organization in all business aspects, including Quality Management and Quality Management System. This work presents results of research conducted on the top management in 204 organizations with introduced quality system. Results show views of top management about the effects of introduced quality system as well as about future steps in terms of improving the same.
5. Continuous, high-resolution spatial mapping of water isotopes: improving tools for quantifying local evaporation and residence times
Dennis, Kate J.; Carter, Jeffrey A.; Winkler, Renato; Downing, Brian; Kendall, Carol; Bergamaschi, Brian
2015-04-01
Stable isotopes of water (d2H, d18O) are unique tracers of many hydrological processes including evaporation, precipitation, reservoir mixing and residence time. Historically, discrete water samples have been collected and analyzed via either Isotope Ratio Mass Spectrometry, or more recently laser-based spectroscopic methods, such as Cavity Ring-Down Spectroscopy (CRDS). However, the analysis of discrete samples precludes the ability to construct high resolution water isotope data sets through time and space. By coupling a recently developed front-end peripheral device (Continuous Water Sampler or CWS) to a CRDS analyzer (Picarro L2130-i), we continuously measured and spatially mapped water isotopes on a transect of the Sacramento River Delta following an extended period of drought. More than two-thousand five-second average d18O and d2H measurements were made aboard the R/V King (USGS) over a six-hour period. In addition to water isotopes, nitrate, chlorophyll, dissolved organic matter (DOM) fluorescence, and other water quality parameters were also measured continuously. As you travel northeast up the delta, surface waters become progressively more enriched in 18O and 2H, while nitrate decreased in concentration and chlorophyll and DOM increased. We utilize the spatially-mapped isotope data within a single transect to understand local evaporation and residence time by (i) utilizing the secondary parameter, d-excess, and (ii) using a simple mass balance model of water moving through the system (inflow, outflow and evaporation). Additional transects, to be conducted during the rainy season, should highlight how the Delta system evolves seasonally. In concert with other data previously collected from the Sacramento River Delta, we suggest the lower region represents a mixture of river waters derived from the Sierra Nevada Mountains and the more marine waters from the mouth of the San Francisco Bay. Moving NE up the Delta into shallow sloughs through flooded wetlands
6. IDegLira Improves Both Fasting and Postprandial Glucose Control as Demonstrated Using Continuous Glucose Monitoring and a Standardized Meal Test
Holst, Jens J; Buse, John B; Rodbard, Helena W;
2016-01-01
: In this substudy, 260 (15.6%) of the original 1663 patients with inadequate glycemic control participating in a 26-week, open-label trial (DUAL I) were randomized 2:1:1 to once-daily IDegLira, insulin degludec or liraglutide. Continuous glucose monitoring (CGM) for 72 hours and a meal test were performed. RESULTS...... meal test than insulin degludec. The improvement is at least partially explained by higher endogenous insulin secretion and improved beta cell function with IDegLira. The benefits of liraglutide on PPG control are maintained across all main meals in the combination....
7. Improving the action requirements of technical specifications: A risk-comparison of continued operation and plant shutdown
Kim, I.S.; Samanta, P.K. [Brookhaven National Lab., Upton, NY (United States); Mankamo, T.
1995-04-01
When the systems needed to remove decay heat are inoperable or degraded, the risk of shutting down the plant may be comparable to, or even higher than, that of continuing power operation with the equipment inoperable while giving priority to repairs. This concern arises because the plant may not have sufficient capability for removing decay heat during the shutdown. However, Technical Specifications (TSs) often require {open_quotes}immediate{close_quotes} shutdown of the plant. In this paper, we present risk-based analyses of the various operational policy alternatives available in such situations, with an example application to the standby service water (SSW) system of a BWR. These analyses can be used to define risk-effective requirements for those standby safety systems under discussion.
8. Signal Processing Algorithms Implementing the “Smart Sensor” Concept to Improve Continuous Glucose Monitoring in Diabetes
Facchinetti, Andrea; Sparacino, Giovanni; Cobelli, Claudio
2013-01-01
Glucose readings provided by current continuous glucose monitoring (CGM) devices still suffer from accuracy and precision issues. In April 2013, we proposed a new conceptual architecture to deal with these problems and render CGM sensors algorithmically smarter, which consists of three modules for denoising, enhancement, and prediction placed in cascade to a commercial CGM sensor. The architecture was assessed on a data set consisting of 24 type 1 diabetes patients collected in four clinical centers of the AP@home Consortium (a European project of 7th Framework Programme funded by the European Committee). This article, as a companion to our prior publication, illustrates the technical details of the algorithms and of the implementation issues. PMID:24124959
9. Improving the action requirements of technical specifications: A risk-comparison of continued operation and plant shutdown
When the systems needed to remove decay heat are inoperable or degraded, the risk of shutting down the plant may be comparable to, or even higher than, that of continuing power operation with the equipment inoperable while giving priority to repairs. This concern arises because the plant may not have sufficient capability for removing decay heat during the shutdown. However, Technical Specifications (TSs) often require ''immediate'' shutdown of the plant. In this paper, the authors present risk-based analyses of the various operational policy alternatives available in such situations, with an example application to the standby service water (SSW) system of a BWR. These analyses can be used to define risk-effective requirements for those standby safety systems under discussion
10. Possibilities of S-EMS utilization for the improvement of central segregation in continuously cast billets in conditions of TŽ
J. Cibulka; D. Bocek; T. Huczala; J. Cupek
2012-01-01
Purpose: The aim of the paper is to investigate practical possibilities of the strand stirrer (S-EMS) for the improvement of inner quality and central segregation in high carbon billets. An optimal S-EMS setting was proposed for the billet caster producing billets 150x150 mm.Design/methodology/approach: Impact of different S-EMS settings on central segregation and inner quality of as-cast billets was investigated. A set of longitudinal and transverse samples were analysed including evaluation...
11. On the Use of Evolutionary Algorithms to Improve the Robustness of Continuous Speech Recognition Systems in Adverse Conditions
Sid-Ahmed Selouani
2003-07-01
Full Text Available Limiting the decrease in performance due to acoustic environment changes remains a major challenge for continuous speech recognition (CSR systems. We propose a novel approach which combines the Karhunen-Loève transform (KLT in the mel-frequency domain with a genetic algorithm (GA to enhance the data representing corrupted speech. The idea consists of projecting noisy speech parameters onto the space generated by the genetically optimized principal axis issued from the KLT. The enhanced parameters increase the recognition rate for highly interfering noise environments. The proposed hybrid technique, when included in the front-end of an HTK-based CSR system, outperforms that of the conventional recognition process in severe interfering car noise environments for a wide range of signal-to-noise ratios (SNRs varying from 16 dB to −4 dB. We also showed the effectiveness of the KLT-GA method in recognizing speech subject to telephone channel degradations.
12. Selection of indicators for continuous monitoring of patient safety: recommendations of the project 'safety improvement for patients in Europe'
Kristensen, Solvejg; Mainz, Jan; Bartels, Paul
2009-01-01
of this paper is to describe a method to select patient safety indicators and present the indicators derived through this process. METHODS: The patient safety indicators were derived and recommended for use in a formalized consensus process based on literature review, targeted information gathering......, expert consultation and rating procedures. RESULTS: A total of 42 indicators, of which 28 originated from existing international indicator programmes, were selected. The processes and outcome indicators that were recommended for institutional-level use in Europe were 24, covering safety of care aspects......BACKGROUND: Initiatives to improve patient safety have high priority among health professionals and politicians in most developed countries. Currently, however, assessment of patient safety problems relies mainly on case-based methodologies. The evidence for their efficiency and reproducibility...
13. Possibilities of S-EMS utilization for the improvement of central segregation in continuously cast billets in conditions of TŽ
J. Cibulka
2012-12-01
Full Text Available Purpose: The aim of the paper is to investigate practical possibilities of the strand stirrer (S-EMS for the improvement of inner quality and central segregation in high carbon billets. An optimal S-EMS setting was proposed for the billet caster producing billets 150x150 mm.Design/methodology/approach: Impact of different S-EMS settings on central segregation and inner quality of as-cast billets was investigated. A set of longitudinal and transverse samples were analysed including evaluation of baumann prints and central segregation by means of LECO method. Samples of wires for segregation survey in rolled products were picked up as well.Findings: It was observed that application of the strand stirrer (S-EMS is capable to suppress central segregation. However, its impact is visible just to a certain stirring level. Subsequent increasing of stirring intensity does not cause further improvement of segregation in the analyzed central part. On the contrary, stronger white band can be seen in the solidification line. Moreover, concentration gradient between the central part and surrounding ring of negative central segregation is lowered. These two effects can play a significant role in the evaluation of segregation level in rolled wires.Research limitations/implications: Analysis of central segregation in a lower size than used 6 mm.Practical implications: Optimal S-EMS setting seems to be 300 A/14 Hz.Originality/value: Impact of S-EMS setting on changes in central segregation of as-cast billets, relationship between central segregation level in wires and cast structure.
Amador B, Z. H. [Centro de Isotopos, Ave. Monumental y Carretera La Rada, Km 3, Guanabacoa, Apartado 3415, Ciudad de La Habana (Cuba)]. e-mail: zabalbona@centis.edu.cu
2006-07-01
The use of safety indicators is common in the nuclear industry. In this work the implementation of indicators for the efficiency analysis of the radiological safety management system of a radioactive installation is presented. Through the same ones the occupational exposure, the training Y authorization of the personnel, the control of practices Y radioactive inventory, the results of the radiological surveillance, the occurrence of radiological events, the aptitude of the monitoring equipment, the management of the radioactive waste, the public exposure, the audits Y the costs of safety are evaluated. Its study is included in the periodic training of the workers. Without this interrelation it is not possible to maintain the optimization of the safety neither to achieve a continuous improvement. (Author)
15. Comprehensive automation and monitoring of MV grids as the key element of improvement of energy supply reliability and continuity
Stanisław Kubacki
2012-03-01
Full Text Available The paper presents the issue of comprehensive automation and monitoring of medium voltage (MV grids as a key element of the Smart Grid concept. The existing condition of MV grid control and monitoring is discussed, and the concept of a solution which will provide the possibility of remote automatic grid reconfiguration and ensure full grid observability from the dispatching system level is introduced. Automation of MV grid switching is discussed in detail to isolate a faulty line section and supply electricity at the time of the failure to the largest possible number of recipients. An example of such automation controls’ operation is also presented. The paper’s second part presents the key role of the quick fault location function and the possibility of the MV grid’s remote reconfiguration for improving power supply reliability (SAIDI and SAIFI indices. It is also shown how an increase in the number of points fitted with faulted circuit indicators with the option of remote control of switches from the dispatch system in MV grids may affect reduction of SAIDI and SAIFI indices across ENERGA-OPERATOR SA divisions.
16. Improving primary care in British Columbia, Canada: evaluation of a peer-to-peer continuing education program for family physicians
MacCarthy Dan
2012-11-01
Full Text Available Abstract Background An innovative program, the Practice Support Program (PSP, for full-service family physicians and their medical office assistants in primary care practices was recently introduced in British Columbia, Canada. The PSP was jointly approved by both government and physician groups, and is a dynamic, interactive, educational and supportive program that offers peer-to-peer training to physicians and their office staff. Topic areas range from clinical tools/skills to office management relevant to General Practitioner (GP practices and “doable in real GP time”. PSP learning modules consist of three half-day learning sessions interspersed with 6–8 week action periods. At the end of the third learning session, all participants were asked to complete a pen-and-paper survey that asked them to rate (a their satisfaction with the learning module components, including the content and (b the perceived impact the learning has had on their practices and patients. Methods A total of 887 GPs (response rates ranging from 26.0% to 60.2% across three years and 405 MOAs (response rates from 21.3% to 49.8% provided responses on a pen-and-paper survey administered at the last learning session of the learning module. The survey asked respondents to rate (a their satisfaction with the learning module components, including the content and (b the perceived impact the learning has had on their practices and patients. The psychometric properties (Chronbach’s alphas of the satisfaction and impact scales ranged from .82 to .94. Results Evaluation findings from the first three years of the PSP indicated consistently high satisfaction ratings and perceived impact on GP practices and patients, regardless of physician characteristics (gender, age group or work-related variables (e.g., time worked in family practice. The Advanced Access Learning Module, which offers tools to improve office efficiencies, decreased wait times for urgent, regular and third
17. Continuous mutual improvement of macromolecular structure models in the PDB and of X-ray crystallographic software: the dual role of deposited experimental data
Macromolecular structures deposited in the PDB can and should be continually reinterpreted and improved on the basis of their accompanying experimental X-ray data, exploiting the steady progress in methods and software that the deposition of such data into the PDB on a massive scale has made possible. Accurate crystal structures of macromolecules are of high importance in the biological and biomedical fields. Models of crystal structures in the Protein Data Bank (PDB) are in general of very high quality as deposited. However, methods for obtaining the best model of a macromolecular structure from a given set of experimental X-ray data continue to progress at a rapid pace, making it possible to improve most PDB entries after their deposition by re-analyzing the original deposited data with more recent software. This possibility represents a very significant departure from the situation that prevailed when the PDB was created, when it was envisioned as a cumulative repository of static contents. A radical paradigm shift for the PDB is therefore proposed, away from the static archive model towards a much more dynamic body of continuously improving results in symbiosis with continuously improving methods and software. These simultaneous improvements in methods and final results are made possible by the current deposition of processed crystallographic data (structure-factor amplitudes) and will be supported further by the deposition of raw data (diffraction images). It is argued that it is both desirable and feasible to carry out small-scale and large-scale efforts to make this paradigm shift a reality. Small-scale efforts would focus on optimizing structures that are of interest to specific investigators. Large-scale efforts would undertake a systematic re-optimization of all of the structures in the PDB, or alternatively the redetermination of groups of structures that are either related to or focused on specific questions. All of the resulting structures should be
18. Continuous mutual improvement of macromolecular structure models in the PDB and of X-ray crystallographic software: the dual role of deposited experimental data
Terwilliger, Thomas C., E-mail: terwilliger@lanl.gov [Los Alamos National Laboratory, Mail Stop M888, Los Alamos, NM 87507 (United States); Bricogne, Gerard, E-mail: terwilliger@lanl.gov [Global Phasing Ltd, Sheraton House, Castle Park, Cambridge CB3 0AX (United Kingdom); Los Alamos National Laboratory, Mail Stop M888, Los Alamos, NM 87507 (United States)
2014-10-01
Macromolecular structures deposited in the PDB can and should be continually reinterpreted and improved on the basis of their accompanying experimental X-ray data, exploiting the steady progress in methods and software that the deposition of such data into the PDB on a massive scale has made possible. Accurate crystal structures of macromolecules are of high importance in the biological and biomedical fields. Models of crystal structures in the Protein Data Bank (PDB) are in general of very high quality as deposited. However, methods for obtaining the best model of a macromolecular structure from a given set of experimental X-ray data continue to progress at a rapid pace, making it possible to improve most PDB entries after their deposition by re-analyzing the original deposited data with more recent software. This possibility represents a very significant departure from the situation that prevailed when the PDB was created, when it was envisioned as a cumulative repository of static contents. A radical paradigm shift for the PDB is therefore proposed, away from the static archive model towards a much more dynamic body of continuously improving results in symbiosis with continuously improving methods and software. These simultaneous improvements in methods and final results are made possible by the current deposition of processed crystallographic data (structure-factor amplitudes) and will be supported further by the deposition of raw data (diffraction images). It is argued that it is both desirable and feasible to carry out small-scale and large-scale efforts to make this paradigm shift a reality. Small-scale efforts would focus on optimizing structures that are of interest to specific investigators. Large-scale efforts would undertake a systematic re-optimization of all of the structures in the PDB, or alternatively the redetermination of groups of structures that are either related to or focused on specific questions. All of the resulting structures should be
19. Continuous improvement concepts as a link between quality assurance and implementation of cleaner production: Case study in the generic pharmaceutical industry
Boltić Zorana
2016-01-01
Full Text Available The subject and the research objective presented in this article is establishing of the relationship between quality assurance and implementation of cleaner production in the generic pharmaceutical industry through the comprehensive concept of continuous improvement. This is mostly related to application of Lean and Six Sigma tools and techniques for process improvement and their link to other known concepts used in the industrial environment, especially manufacturing of generic pharmaceutical products from which two representative case studies were selected for comparative analysis, also considering relevant regulatory requirements in the field of quality management, as well as appropriate quality standards. Although the methodology discussed in this conceptual and practice oriented article is strongly related to chemical engineering, the focus is mainly on process industry, i.e. production systems, rather than any specific technological process itself. The scope of this research is an engineering approach to evaluation of the production systems in terms of continuous improvement concepts application, considering both quality aspects and efficiency of such systems. [Projekat Ministarstva nauke Republike Srbije, br. TR 34009
20. Key Factors for a High-Quality Peritoneal Dialysis Program — The Role of the PD Team and Continuous Quality Improvement
Fang, Wei; Ni, Zhaohui; Qian, Jiaqi
2014-01-01
The proportion of end-stage renal disease (ESRD) patients on peritoneal dialysis (PD) has increased very fast in China over the last decade. Renji Hospital, affiliated with Shanghai Jiaotong University School of Medicine, is a recognized high-quality PD unit with a high PD utilization rate, excellent patient and technique survival (1-year and 5-year patient survival rate of 93% and 71%, and 1-year and 5-year technique survival of 96% and 82%, respectively), low peritonitis rate and a well-documented good quality of life of the treated patients. We believe that a dedicated and experienced PD team, a structured patient training program, continuous patient support, establishing and utilizing standardized protocols, starting PD with low dialysis dose, monitoring key performance indicators (KPIs), and continuous quality improvement (CQI) are the key factors underlying this successful PD program. PMID:24962961 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3215848207473755, "perplexity": 4996.14875985783}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-50/segments/1480698542665.72/warc/CC-MAIN-20161202170902-00163-ip-10-31-129-80.ec2.internal.warc.gz"} |
https://www.gradesaver.com/textbooks/math/precalculus/precalculus-6th-edition-blitzer/chapter-11-section-11-4-introduction-to-derrivatives-concept-and-vocabulary-check-page-1174/4 | ## Precalculus (6th Edition) Blitzer
The slope of the tangent line to the graph of a function $y=f\left( x \right)$ at $\left( a,f\left( a \right) \right)$ is given by $\underset{h\to 0}{\mathop{\lim }}\,$ $\frac{f\left( a+h \right)-f\left( a \right)}{h}$ provided that this limit exists. Also, the derivative of the function is given by ${f}'\left( x \right)=\underset{h\to 0}{\mathop{\lim }}\,\frac{f\left( a+h \right)-f\left( a \right)}{h}$. Thus, the derivative of a function $f$ gives the slope of $f$ for any value of x in the domain of $f'$. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.905525267124176, "perplexity": 35.7789951935857}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-24/segments/1590347391309.4/warc/CC-MAIN-20200526191453-20200526221453-00289.warc.gz"} |
http://dragly.org/2009/10/11/revision-and-build-numbers-for-your-netbeans-apps/comment-page-1/ | # Revision and build numbers for your NetBeans apps
After going through a couple of guides on the net, I figured out how to add build numbers and revision numbers to my NetBeans projects. The build number will be incremented for each build, and the revision number is gathered from your subversion repository. If you don’t use Subversion just skip that part and add the revision number manually.
In this tutorial I assume you are creating an application based on the NetBeans Desktop Application wizard. Otherwise, you may just follow along and use whatever fits into your project. All you need is a java project being built by Ant (as all NetBeans projects are).
First of all, figure out where the properties file for your application is located. This should be in [package name].resources (or if you are browsing the files, you will find it under /src/[package name]/resources) and is named the same as your application with the suffix “.properties“.
This could for instance be myapp.resources/myapp.properties or /src/myapp/resources/myapp.properties.
Open it up and find the version property. It should look something like this:
Application.version = 1.0
Change this to the following
Application.version = 1.0.0.${Application.buildnumber} Now, we are ready to add a build number to your build.xml file. This is found in the nbproject folder if you browse for files (not in the Projects browser). Add the following lines below the <import file="nbproject/build-impl.xml"/> by replacing [Package Name] and [App Name] with your own values. <target name="-post-jar" description="Sets the buildversion for the current build"> <propertyfile file="${src.dir}/[Package Name]/[App Name].properties">
<entry key="Application.buildnumber" value="1" type="int" operation="+"/>
</propertyfile>
</target>
This should now add your build number to your version number. If you want to have the version in the main title bar of your application just go back into the properties file and change the Application.title property to something like this:
Application.title = My Application Name ${Application.version} ### Adding the Subversion revision number Go back to your build.xml file and add the following below everything else: <target name="-post-init" description="Sets the buildversion for the current build"> <exec outputproperty="svna.version" executable="svnversion"> <arg value="-c" /> <redirector> <outputfilterchain> <tokenfilter> <replaceregex pattern="^[0-9]*:?" replace="" flags="g"/> <replaceregex pattern="M" replace="" flags="g"/> </tokenfilter> </outputfilterchain> </redirector> </exec> <propertyfile file="${src.dir}/[Package Name]/[App Name].properties">
<entry key="Application.revision" value="${svna.version}" type="int" operation="="/> </propertyfile> <echo>Revision found from SVN:${svna.version}</echo>
</target>
Then, add the revision number to your version number by editing changing the Application.version property to something like this:
Application.version = 1.0.${Application.revision}.${Application.buildnumber}
This should be all it takes. Just leave a comment if it does not work out as expected.
### Working with national characters
If you’d like to use national characters, you have to edit the propertyfile line like this:
<propertyfile file="${src.dir}/[Package Name]/[App Name].properties" jdkproperties="true"> Thanks to Poli for this tip! ## 18 thoughts on “Revision and build numbers for your NetBeans apps” 1. Sebastian says: Hi, there seems to be something missing after Add the following lines below the by replacing [Package Name] and [App Name] with your own values. and Go back to your build.xml file and add the following below everything else: Doesn’t seems to be working anymore, bellow everything else? Below ? I’m using netbeans 6.9 Do you have a solution? Would be much appreciated 2. Hi Sebastian! Thanks for pointing this out. It seems like the syntax highlighter WP-Syntax didn’t handle the WordPress editor too well and ended up escaping all relevant code. I’ve replaced the highlighter with a new one, so the code should be up and running again. Seems like it has been missing for quite some time, so again, thanks for finding this error. If the method described in this post still works for Netbeans 6.9, please give me a note. I haven’t tested it since 6.7. 3. Winanjaya says: Hi.. nice.. do you have for NetBeans 6.9 version? thanks a lot in advance Regards 4. I haven’t tested the code with NetBeans 6.9, but according to the above pingback it appears to still be working. Just post back if you encounter any errors. 5. Jakub Dominik says: Really helpful post. Thanks a lot. 6. Aidan Hannigan says: Thanks for this useful post. Works for me in NB7. I made a few changes to output the version to a HTML template so it could be included in the footer. ${Application.version}
7. Poli says:
First of all, thanks for useful post! For all of us who need to use national characters (like czech čžšř…) might be useful to change propertyfile tasks entries to something like this:
<propertyfile file="${src.dir}/encodingTest/resources/EncodingTestApp.properties" jdkproperties="true" at least with Ant 1.8.2 and unmodified entry it broke escaped characters in .properties file every second run of ant, modified entry delete some comments, but key-value pairs are as they should be 1. Thanks for the tip. I’m actually using national characters like æøå myself, but I guess I never did with regards to this code. I’ve added it to the post now 8. Hey! Thanks for the tip. However, it is not working for me in Netbeans 6.9. Whatever change I make to my properties file is never reflected in my app. It’s as if Netbeans was undoing any changes I make. I did as you said: Application.title = ArbBook v{Application.version} Application.version = 0.9.{Application.buildnum} However my title bar keeps showing ‘ArbBook’ only (the value prior to my mod) and if I go to the About box the version num. is fixed at ’1.0′. Any clue of what am I doing wrong? Thanks again for your time. 1. Poli says: Check if value of Application.buildnum key in property file is increasing, this means, that build.xml is workink properly, if it’s not increasing, you’ve probably bad path to property file. Then check in NB, if version label is associated with application scope property Application.version, I think its default is class scope property file, which is [YourProject]AboutBox.properties by default. And finally, in your code snippet dollar signs before compound brackets are missing, so check this as well. 1. Hi again! Thanks for the prompt response. You’re right, I totally missed the$ signs! Still, no changes at all. The new Application.buildnum property is not being written, and I’m pretty sure my paths are ok. As previously, any changes I make by hand to my App.properties seem to do nothing. I checked my AboutBox.properties and it actually refers to variables like ${Application.title} and${Application.version} so it should be affected by these. Also, if I change this file manually nothing happens! It’s as if these files were being recreated from scratch everytime I build the app or something… This is weeeird!
1. Found it!
“Please pay attention that NB in “compile on save” mode doesn’t monitor changes in properties files, so you need to clean/build entire project. ”
The changes were simply not being copied to the build dir…
9. Simba says:
Hi, We are running into an interesting with the .properties file. We are using Maven for building and packaging our source code. As a part of the build we are generating a .properties file which is updated with the version number of one of our 3rd party dependencies. The issue we are running into is , when we do a clean build the version number gets updated correctly, however when we try to run the project the version number is overwritten back to it’s variable name .
For example if the property file has a variable called {twitter.api.jar.version} . this variable gets replaced by the correct value (in this case it’s the version of the Twitter jar dependency) only when we do a clean build. if we subsequently run the project then for some reason the variable value is replaced by the variable name .
Any idea what could be going wrong here? Appreciate if you have any inputs
1. Hi! I’m afraid I can’t remember experiencing anything similar, so off the top of my head I don’t have any solution. I would suggest having a look at the build.xml file to see if there is anything happening for a run target or similar. Perhaps you have added something like
<entry key="twitter.api.jar.version" value="${twitter.api.jar.version}"> without the$-sign?
10. David Elson says:
It is as Simba has described (probably meant {twitter.api.jar.version}).
I have a .properties file, maven project, netbeans 7.2. When I do a clean build, the src properties file appears in the target directory with the variable correctly expanded, per maven filtering.
However, when I then do run or debug from the IDE, the variable is immediately set back to its symbolic name in the target properties file, rendering the session useless.
Simba, you are not hallucinating. This is a problem (imho).
-David
11. David Elson says:
Correction to my typo ==> (probably meant \${twitter.api.jar.version}) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2977817952632904, "perplexity": 2100.131655559002}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-35/segments/1409535919886.18/warc/CC-MAIN-20140909051335-00256-ip-10-180-136-8.ec2.internal.warc.gz"} |
https://zims-en.kiwix.campusafrica.gos.orange.com/wikipedia_en_all_nopic/A/Triacontadigon | In geometry, a triacontadigon (or triacontakaidigon) or 32-gon is a thirty-two-sided polygon. In Greek, the prefix triaconta- means 30 and di- means 2. The sum of any triacontadigon's interior angles is 5400 degrees.
TypeRegular polygon
Edges and vertices32
Schläfli symbol{32}, t{16}, tt{8}, ttt{4}
Coxeter diagram
Symmetry groupDihedral (D32), order 2×32
Internal angle (degrees)168.75°
Dual polygonSelf
PropertiesConvex, cyclic, equilateral, isogonal, isotoxal
An older name is tricontadoagon.[1] Another name is icosidodecagon, suggesting a (20 and 12)-gon, in parallel to the 32-faced icosidodecahedron, which has 20 triangles and 12 pentagons.[2]
The regular triacontadigon can be constructed as a truncated hexadecagon, t{16}, a twice-truncated octagon, tt{8}, and a thrice-truncated square. A truncated triacontadigon, t{32}, is a hexacontatetragon, {64}.
One interior angle in a regular triacontadigon is 16814°, meaning that one exterior angle would be 1114°.
The area of a regular triacontadigon is (with t = edge length)
{\displaystyle {\begin{aligned}A=&8t^{2}\cot {\frac {\pi }{32}}\\=&8t^{2}\left(1+{\sqrt {2}}+{\sqrt {4+2{\sqrt {2}}}}+{\sqrt {8+4{\sqrt {2}}+2{\sqrt {20+14{\sqrt {2}}}}}}\right)\end{aligned}}}
${\displaystyle r={\frac {1}{2}}t\cot {\frac {\pi }{32}}}$
{\displaystyle {\begin{aligned}R=&{\frac {1}{2}}t\csc {\frac {\pi }{32}}\\=&{\frac {1}{2}}t\left({\sqrt {16+8{\sqrt {2}}+4{\sqrt {20+14{\sqrt {2}}}}+2{\sqrt {168+116{\sqrt {2}}+2{\sqrt {13780+9742{\sqrt {2}}}}}}}}\right)\end{aligned}}}
### Construction
As 32 = 25 (a power of two), the regular triacontadigon is a constructible polygon. It can be constructed by an edge-bisection of a regular hexadecagon.[3]
## Symmetry
The symmetries of a regular triacontadigon. Lines of reflections are blue through vertices, and purple through edges. Gyrations are given as numbers in the center. Vertices are colored by their symmetry positions.
The regular triacontadigon has Dih32 dihedral symmetry, order 64, represented by 32 lines of reflection. Dih32 has 5 dihedral subgroups: Dih16, Dih8, Dih4, Dih2 and Dih1 and 6 more cyclic symmetries: Z32, Z16, Z8, Z4, Z2, and Z1, with Zn representing π/n radian rotational symmetry.
On the regular triacontadigon, there are 17 distinct symmetries. John Conway labels these lower symmetries with a letter and order of the symmetry follows the letter.[4] He gives r64 for the full reflective symmetry, Dih16, and a1 for no symmetry. He gives d (diagonal) with mirror lines through vertices, p with mirror lines through edges (perpendicular), i with mirror lines through both vertices and edges, and g for rotational symmetry. a1 labels no symmetry.
These lower symmetries allows degrees of freedoms in defining irregular triacontadigons. Only the g32 subgroup has no degrees of freedom but can seen as directed edges.
## Dissection
regular Isotoxal
Coxeter states that every zonogon (a 2m-gon whose opposite sides are parallel and of equal length) can be dissected into m(m-1)/2 parallelograms.[5] In particular this is true for regular polygons with evenly many sides, in which case the parallelograms are all rhombi. For the regular triacontadigon, m=16, and it can be divided into 120: 8 squares and 7 sets of 16 rhombs. This decomposition is based on a Petrie polygon projection of a 16-cube.
A triacontadigram is a 32-sided star polygon. There are seven regular forms given by Schläfli symbols {32/3}, {32/5}, {32/7}, {32/9}, {32/11}, {32/13}, and {32/15}, and eight compound star figures with the same vertex configuration.
Many isogonal triacontadigrams can also be constructed as deeper truncations of the regular hexadecagon {16} and hexadecagrams {16/3}, {16/5}, and {16/7}. These also create four quasitruncations: t{16/9} = {32/9}, t{16/11} = {32/11}, t{16/13} = {32/13}, and t{16/15} = {32/15}. Some of the isogonal triacontadigrams are depicted below as part of the aforementioned truncation sequences.[6]
## References
1. A Mathematical Solution Book Containing Systematic Solutions to Many of the Most Difficult Problems by Benjamin Franklin Finkel
2. Weisstein, Eric W. "Icosidodecagon". MathWorld.
3. Constructible Polygon
4. John H. Conway, Heidi Burgiel, Chaim Goodman-Strauss, (2008) The Symmetries of Things, ISBN 978-1-56881-220-5 (Chapter 20, Generalized Schaefli symbols, Types of symmetry of a polygon pp. 275-278)
5. Coxeter, Mathematical recreations and Essays, Thirteenth edition, p.141
6. The Lighter Side of Mathematics: Proceedings of the Eugène Strens Memorial Conference on Recreational Mathematics and its History, (1994), Metamorphoses of polygons, Branko Grünbaum | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 3, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7049764394760132, "perplexity": 10098.928336245996}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-31/segments/1627046154798.45/warc/CC-MAIN-20210804080449-20210804110449-00479.warc.gz"} |
http://mahalonottrash.blogspot.com/2009/08/way-of-brick.html | ### The Way of the Brick
A brand new Lego Store (Hawaii's first) recently opened at Ala Moana Center and Owen has already been there twice and come back richer in lego bricks each time. However, while Owen is a frequent customer, until today I hadn't yet visited the wonder that is the Lego Store. As a kid I played with Legos just about daily from age 6 through high school. But since leaving home I've rarely made enough money to indulge in Lego kits, and to be honest I haven't had much time. But now that Owen is 4, he has the hand-eye coordination and patience to build some pretty impressive creations.
So today I decided to make my first visit to the Hawaii Lego Store. Owen, of course, joined me. He has had his eye on a yellow Creator prop-driven airplane for some time, often walking around the house with his catalog letting us know that today would be a good day to buy the plane in case we were interested. But what I didn't recognize from the tiny photo in the catalog is that the yellow prop-driven plane is AWESOME! It's much bigger and more detailed than the red Creator jet Owen purchased with his birthday money last month. And compared to the clunky airplanes I used to build back in the day? Forget it. Legos have come a long way in the past 15 years.
So when I saw Creator #6745 in the store I felt a rush of memories about constructing an intricate model starting from the myriad tiny pieces and slowly building toward the final objective. I needed that kit. Owen needed that kit. But I don't want to spoil the boy. He shouldn't think that just because we go to a toy store that he should get something new. And I don't want Owen to be one of those kids who has so many toys that he's bored with them.
I stood there with Owen, mesmerized by the brilliant illustrations on the Lego box. I then started hearing the voices of the proverbial devil and angel resting on my shoulders. The devil suggested that it wouldn't be Owen's toy, it would be mine. I've had a really productive year, so I should reward myself! But then the angel chimed in and said: "Dammit, just buy it!"
So it was unanimous. Here's a time-lapse video of the plane's construction, followed by some photos of the finished model. Oh man, I'm hooked once again! I know what Owen and Marcus are getting for Christmas...and Thanksgiving and Halloween...
(The time-lapse was shot at 4 frames per minute and play-back is at 24 fps, shot with Gawker and my iSight camera. It took us almost exactly an hour to build the plane. Facebookers, check out our blog for the video if it doesn't show up here.)
blissful_e said…
Ben says you always had more legos than anyone else he knew! We're glad to see the tradition continuing. :)
JohnJohn said…
Yeah, I loaned those legos to the child of a friend and I haven't seen them since 1998 or so. Ah well, it's fun starting over again. I predict that Owen, Marcus and I will surpass my old collection in no time!
Amy Pousson said…
You know what that plane needs? Pew-Pew guns!!
Jackie O. said…
Erin- jonah and noah LOVE legos! have u guys seen the new legos that have letters on them that the kids can make word with? they are so awesome and educational (there goes my teacher self)!
### On the Height of J.J. Barea
Dallas Mavericks point guard J.J. Barea standing between two very tall people (from: Picassa user photoasisphoto).
Congrats to the Dallas Mavericks, who beat the Miami Heat tonight in game six to win the NBA championship.
Okay, with that out of the way, just how tall is the busy-footed Maverick point guard J.J. Barea? He's listed as 6-foot on NBA.com, but no one, not even the sports casters, believes that he can possibly be that tall. He looks like a super-fast Hobbit out there. But could that just be relative scaling, with him standing next to a bunch of extremely tall people? People on Yahoo! Answers think so---I know because I've been Google searching "J.J. Barea Height" for the past 15 minutes.
So I decided to find a photo and settle the issue once and for all.
I then used the basketball as my metric. Wikipedia states that an NBA basketball is 29.5 inches in circumfe…
### The Force is strong with this one...
Last night we were reviewing multiplication tables with Owen. The family fired off doublets of numbers and Owen confidently multiplied away. In the middle of the review Owen stopped and said, "I noticed something. 2 times 2 is 4. If you subtract 1 it's 3. That's equal to taking 2 and adding 1, and then taking 2 and subtracting 1, and multiplying. So 1 times 3 is 2 times 2 minus 1."
I have to admit, that I didn't quite get it at first. I asked him to repeat with another number and he did with six: "6 times 6 is 36. 36 minus 1 is 35. That's the same as 6-1 times 6+1, which is 35."
Ummmmm....wait. Huh? Lemme see...oh. OH! WOW! Owen figured out
x^2 - 1 = (x - 1) (x +1)
So $6 \times 8 = 7 \times 7 - 1 = (7-1) (7+1) = 48$. That's actually pretty handy!
You can see it in the image above. Look at the elements perpendicular to the diagonal. There's 48 bracketing 49, 35 bracketing 36, etc... After a bit more thought we…
### The Long Con
Hiding in Plain Sight
ESPN has a series of sports documentaries called 30 For 30. One of my favorites is called Broke which is about how professional athletes often make tens of millions of dollars in their careers yet retire with nothing. One of the major "leaks" turns out to be con artists, who lure athletes into elaborate real estate schemes or business ventures. This naturally raises the question: In a tightly-knit social structure that is a sports team, how can con artists operate so effectively and extensively? The answer is quite simple: very few people taken in by con artists ever tell anyone what happened. Thus, con artists can operate out in the open with little fear of consequences because they are shielded by the collective silence of their victims.
I can empathize with this. I've lost money in two different con schemes. One was when I was in college, and I received a phone call that I had won an all-expenses-paid trip to the Bahamas. All I needed to do was p… | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.18871156871318817, "perplexity": 2504.544517147911}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-34/segments/1534221210362.19/warc/CC-MAIN-20180815220136-20180816000136-00049.warc.gz"} |
https://link.springer.com/article/10.1007/s11192-017-2244-y | ## Introduction
Peer review is the fundamental process used by the scientific community to select and to ensure the quality of academic publications (cf. e.g., Alberts et al. 2008; Bornmann 2013; Squazzoni and Takács 2011). Several generations of scientists have contributed high-quality reviews, while only authorship has been credited for academic career. It is not easy to rationalize why researchers provide impartial reviews and constructive advice voluntarily, as they need to sacrifice time that could be used for their own research activities (Bernstein 2013). In consequence, it is a puzzle how the system of peer review can be sustainable at all.
We target the understanding of this puzzle and the consequent foundational problems of scientific development by creating and analyzing a simple agent-based model. The model considers a community of scientists who write and evaluate the papers of each other under different filtering policies of journal editors. Among other agent-based models of peer review, such as Gilbert (1997), Squazzoni and Gandelli (2012), Kovanis et al. (2016), Day (2015) and Bianchi et al. (2017), the main strength of the current study lies in the fact that it targets the motivational trap of reviewers and highlights that the trap also implies free riding behavior in scientific production. We seek solutions within the model that could potentially guide recommendations for editorial policies to ensure the selection of high quality publications.
The puzzle concerned can be described as a double social dilemma game where scientists can choose levels of efforts for reviews and manuscripts (cf. Bianchi et al. 2017; Squazzoni et al. 2013). Given the presence of costs in terms of time and effort, no contribution (sloppy review) is the best reply strategy for reviews. When all reviewers play according to their best reply strategy, the resulting outcome is no scientific control on the quality of submitted papers. The dominant strategy equilibrium of low quality reviews means that submissions need not be of high quality. Due to the immense costs of producing high quality work, authors are best off by submitting poor manuscripts and waiting for the publication of their work by chance. In short, in the lack of explicit sanctions and incentives, low-quality submissions and low-quality reviews form the dominant strategy equilibrium in the double social dilemma of scientific production.
Social dilemmas are difficult to resolve in general, and those that lack clear benefits of mutual cooperation are troublesome in particular. Substantiating and internalizing the values of scientific development that could be considered as the reward of cooperation is therefore crucial. The most evident improvement might come from introducing higher payoffs for cooperation. For instance, a public good reward for overall cooperation can be established. The good standing of a journal is achieved with excellent publication material and public awareness of its high standards of review. This good standing is a public good that benefits all authors who published in the given outlet. When taken into account in academic career, journal metrics, such as the impact factor, serve as indicators of quality—irrespective of having them deserved with hard work or acquiring them undeservedly with luck.
Another straightforward modification of the payoff scheme of the social dilemma is the application of selective incentives (Olson 1965): the allocation of additional benefits for authors of high-quality papers (e.g., promotion and grants, which is current practice) and for reviewers writing high-quality reports (which is rare practice).
Direct (Hamilton and Axelrod 1981; Axelrod 1984) and indirect reciprocity (Boyd and Richerson 1989; Milinski et al. 2001, 2002a, b; Nowak and Sigmund 2005; Semmann et al. 2005; Nowak 2006) are potential solutions to social dilemmas, if the chance of repetition is high and the opportunities for retaliation are in foresight. In the context of peer review, indirect reciprocity can be facilitated, for instance, by rotating the roles of authors, reviewers, and editors (Bravo et al. 2015). The social embeddedness of scientific production further enhances the chance of solving the social dilemma efficiently (Coleman 1986; Barrera 2008). The small world aspect of working in specific fields noted by Newman (2001) and the intertwined network of co-authorship (Bianchi et al. 2017), participation in international project consortia, and hangouts at conferences all reduce the competitiveness and contribute to the pro-social character of reviewing.
Furthermore, once informal communication, gossip, reputation, image scoring, and stratification enter into the structure of the social dilemma, cooperation might emerge and be maintained (Sommerfeld et al. 2007, 2008). Recording of and relying on reputational scores have become a catalyst of cooperation in many areas of life (Dellarocas 2003). Reputation is one of the most important motivations for scientists to work hard, while it is also used as a signal of high quality. When reputation is increasingly taken into account for judging scientific quality, the “rich will get richer”, generating a Matthew effect (Merton et al. 1968; Newman 2001; Squazzoni and Gandelli 2012; Wang 2014; Perc 2014). Earlier achievement and reputational information certainly play an important role in current practice both for editorial and reviewer decisions (Paolucci and Sichman 2014).
Social incentives that are associated with direct and indirect reciprocity and the social embeddedness of peer review might be key mechanisms that rationalize cooperative behavior of reviewers. The importance of social incentives is highlighted by surveys asking for the motivations of reviewers (Malicki et al. 2016; Warne 2016). In fact, monetary incentives might be in conflict with or drive out social incentives when applied to reviewers (Squazzoni et al. 2013; Chetty et al. 2014).
In this paper, we build on the view that the aim of peer review is to ensure the selection of valuable scientific papers for publication (Gilbert 1997). The model emphasizes the costly character of high-quality manuscript submissions and reviewer contributions. We take it as granted that high-quality submissions lead to better science, while reviews impact scientific quality only indirectly. Our model makes radical simplifications on the practical aspects of the peer review system intentionally. This way, we aim at providing a straightforward assessment of the institutional conditions and editorial policies under which authors are directly motivated to produce high-quality submissions and reviewers are motivated to provide high quality reviews. Hence, we are primarily interested in the emergence of cooperation that results in the selection of scientific quality.
The rest of this paper is divided in three sections. In “The model” section, we introduce our agent-based model of scientific work and peer review. We report simulations results in the “Results” section and conclude in the “Conclusion” section.
## The model
### The baseline model of peer review
We build an agent based model which contains N scientists writing single-author papers. At each discrete period t, each scientist performs both the task of author—by producing one article—and the one of reviewer. Authors and reviewers comprise of an identical set of agents. For the sake of simplicity, we consider a single journal with a single editor, who is not an author or a reviewer in the journal.
Authors can produce low or high quality contributions that they submit to the editor who considers them in random order. The editor selects $$\mu$$ (set to two in our simulations, as this is the most common practice in most journals) reviewers for each paper chosen uniformly at randomFootnote 1 with an upper limit of reviews for each reviewer k (the value of k is set to 4 without loss of generality, as shown in the robustness check reported in Fig. 14). We assume that reviewers always accept requests, but they do not necessarily invest high effort in performing reviews. It is of their strategic decision to produce a low quality review at low cost (normalized to zero) or a high quality review at high cost (E). The former is the best reply strategy of the reviewer if no further incentives are provided. The review is translated into a binary recommendation (accept or reject) which is passed on to the editor. We assume that the recommendation is random with fifty–fifty percent chance of accept or reject in case of low reviewer effort and reflects the quality of the submission perfectly in case of high reviewer effort. The editor’s decision is based on incoming recommendations and it has a binary outcome: accept or reject. We consider a single round of review. Acceptance benefits the author, but benefits the editor (the journal and scientific development in general) only if the submission was of high quality.
The incentive structure and the strategy space of the game are defined as follows. The editor wants to maximize high-quality scientific output in the journal and would like to minimize the number of low-quality articles appearing in the journal. This means that similarly to the model of Bianchi et al. (2017), papers that are accepted and of bad quality are the most harmful for the journal (Squazzoni and Gandelli 2012). These values are used as output measures to evaluate the performance of the entire system in our simulations.
The situation is of asymmetric information (Squazzoni et al. 2013), in which the editor is unable to assess the true quality of submissions or the true effort of reviewers. The true quality of accepted papers is revealed probabilistically after publication (we fix the revelation probability $$P_{reveal}=1$$ in the simulations reported) and there is no way for the editor to assess the true quality of rejected submissions. The crucial parts of editorial policy are therefore the selection of reviewers who can be trusted for their recommendations and the extent of reliance on reviewer recommendations. Several strategies could possibly be used in order to arrive at a proper conclusion. We vary these editorial strategies in between simulations, because these could be easily translated into policy recommendations.
Keeping a reputational account of scientists is part of possible editorial strategies. Editorial reputations of scientists are improved largely by good publications (named GP), degraded even more by bad publications (BP) and worsened by rejected submissions (Rej). Moreover, the editor is in a privileged position to overview the reviewer activities of scientists. Every good review scientists write (GR) increases, while every bad review they write (BR) decreases their editorial reputation. The quality of the review is only determined for the editor after publication. Good reviews are those where the paper is revealed of the same quality of what the reviewer said. Bad reviews are those where there is a difference, i.e. where the paper is revealed as bad while the reviewer said that it was good or where the paper was revealed as good, but the reviewer recommended rejection (in case of conflicting reviews). Finally reviews for rejected papers are considered of good quality if they recommended rejection, and of bad quality otherwise. Please note the asymmetric character of reviewer bias: as the high quality of rejected papers is never revealed, rejection is a safer strategy for reviewers (a rejection recommendation can only turn out to be a bad review in case other reviewers recommended publication, the paper has been published, and its true high quality has been revealed). In summary, the editorial reputation of scientist i is given as:
\begin{aligned} REP_i^E = \#GP-\#Rej- \alpha \cdot \#BP+ \gamma \cdot (\#GR-\#BR) \end{aligned}
(1)
where $$\#Rej=\#BN+\#GN$$ (the sum of bad and good rejected papers), $$0<\gamma \ll 1.$$ Parameter $$\alpha >1$$ represents the relative detrimental effect for the journal reputation of accepting a low quality paper. The parameter $$\gamma$$ represents instead the relative weight of the agent’s behaviour as referee compared to the one as author. For the sake of our simulations both parameters are set conservatively in order to avoid favouring the emergence of cooperative behaviours. Indeed, $$\gamma$$ is fixed to 0.10, meaning that the behaviour of the author as reviewer of peers’ papers weights one tenth of its behaviour as author. Similarly $$\alpha =2$$ in all our simulations meaning that the detrimental effect of publishing a bad paper is twice as important as the positive effect on reputation of the publication of a high quality paper. Small variations around these values do not materially change the results discussed in the “Results” section. Note that, given the specification of Eq. (1), as papers and reviews grow over time $$REP_i^E$$ can grow or decrease unboundedly. However, the absolute value of authors’ reputation is not salient for editorial decisions, which only uses relative reputations to eventually bias its decisions (as noted in the “Reputation-based selection and journal impact factor” section).
Incoming reviews are assumed to lead to editorial conclusions according to an editorial policy which is assumed to be fixed and not updated within a simulation. We manipulate editorial strategies between the simulations in order to compare the effectiveness of these policies. Editorial strategies differ with regard to the handling of conflicting reviews and relying on author reputations in desk rejection and acceptance. The latter element is only added in the extended model presented in the “Reputation-based selection and journal impact factor” section. In the simulations reported, we consider four editorial strategies with regard to the handling of conflicting reviews. For all of them, if all referees agree, then the editor follows the unanimous advice. In case of disagreement, the editor can use one of the following strategies:
• AP: Reject the paper (i.e., the editor accepts a paper only if All reviews are Positive);
• 1P: Accept the paper (i.e. the editor accepts the paper if at least 1 review is Positive);
• ER: Follow the advice of one of the referees chosen at random probability proportional to the relative Editorial Reputations of the referees;
Authors have perfect information about the quality of their own submissions. Similarly to the model of Bianchi et al. (2017), authors decide to submit a paper of low quality (at zero cost) or at high quality (at cost e). They are best off with the publication of their low-quality papers (BP). Thus, their preference order is: $$BP> GP> BN > GN$$.
When in the role of reviewers, scientists first accept editorial requests to review submissions. We assume that this does not entail any significant costs: the time spent on pushing the “accept” button in an editorial managerial system is negligible and the social costs of being committed to reviewing are counterbalanced by gaining access to papers before their publication. Once papers are assigned to reviewers, they decide to invest low effort (at zero cost) or high effort (at cost E) in performing the task. Thus, low effort is the best reply strategy of reviewers.
For the sake of simplicity, we assume that all individual payoffs are in the positive domain. Hence the costs e and E could be considered as opportunity costs of time that are lost by high effort investments in the given period ($$0<E<e$$).Footnote 2 Altogether, writing high quality papers as well as writing high quality reviews entail sacrificing valuable research and leisure time for scientists.
We disregard the potential time conflict between writing high-quality papers and reviews. In models of (Bianchi et al. 2017; Kovanis et al. 2016), scientists need to allocate time between submissions and reviewing. In our model, both activities are costly if they are performed well and it is not a necessity that scientists invest high effort in one of them. At the same time, we assume no gain from not being published. A publication always yields a positive return ($$V_{acc}=3$$) that outweighs the costs of high effort e.
In line with the current duality of practices, two cases are compared: single blind and double blind reviews (Seeber and Bacchelli 2017). In case of single blind reviews, reviewers can condition their recommendations on the reputation of the author. In case of double blind reviews, only the editor is able to make decisions based on the reputation of authors. In case of a single blind review system, the reviewer strategy can be conditional on the public reputation of the author. Unlike the editorial reputation of authors, the public reputation of an author i depends only on published papers and does not severely punishes bad publications:
\begin{aligned} REP_i^P = \#GP-\#BP \end{aligned}
(2)
Agents’ strategies As reviewers are also authors, the strategies concerning the two aspects of the scientist’ work are bundled and are characterized by the following elements:
• A decision for the production of manuscripts, that can be either:
• c: produce manuscripts of high quality (cooperation)
• d: produce manuscripts of low quality (defection)
• A decision for the production of reviews, that can be either:
• C: produce reviews at high effort (cooperation)
• D: produce reviews at low effort (defection)
• Rep: exercise high effort with a likelihood that is proportional to the public reputation of the author of the paper (cooperation conditional on reputation).Footnote 3
Individual strategies are assigned to scientists at the start randomly and in equal numbers for each combination. This results in four bundled strategies for the double blind case and in six bundled strategies for the single blind case. Authors decide according to their strategy types to submit a paper of low quality or at high quality (at high cost), which is sent out for review according to the rules determined by the editorial policy. Reviewers act according to their strategies and provide recommendations of accept or reject to the editor. Papers are selected for publication as a result of the recommendations of the reviewers and the editorial policy.
The evolution of individual strategies The evolution of author/reviewer strategies is modeled with a replicator dynamics rule adjusted to a finite population. Scientists tend to adopt strategies that ensured higher average payoffs in the previous time period in the population, while they tend to disregard strategies that resulted in lower payoffs.
The author/reviewer’ payoff at the end of each period t is defined as the payoff from accepted papers minus the efforts invested in writing manuscripts and reviews, as: $$V_{acc}-e(GP^t+GN^t)- E\cdot \#GR$$. The first term $$V_{acc}$$ is the baseline payoff of publishing a paper and it is set to 3 if the paper produced by this author was published, zero otherwise. The second term is the cost of producing the paper, and is set to $$e=1$$ if the paper is of high quality (regarless of the fact that it has been published), zero otherwise. The last term accounts for the cost E a reviewer has to pay for each paper reviewed with high effort.
Each individual has a probability $$P_{evo}=0.01$$ of being selected for updating his strategy. If this happens, then his new strategy is selected randomly with a probability proportional to the difference of the given strategy to the average expected payoff, weighted for the current strategy frequencies. Formally, the expected new population size for strategy j is given by:
\begin{aligned} N_j^{t+1}= N_j^t + \left( N_j^t\cdot \overline{ P^t_j} - N^t_j\cdot \overline{P_t}\right) \delta \end{aligned}
(3)
where $$\overline{P^t_j}$$ is the average payoff of strategy j, while $$\overline{P_t}$$ is the average payoff in the whole population and $$\delta$$ is the speed of evolution.Footnote 4 We constrain the finite replicator dynamics process such that all strategies are represented by an integer number of agents in the population and no $$N_j^{t+1}<0$$. Note that the strategies of agents evolve and not the agents are replaced. This means that agents accumulate editorial and public reputation throughout the simulation.
### Reputation-based selection and journal impact factor
In order to keep the model simple and to concentrate on some key mechanisms, other details are fixed to some natural values and some possible elements can be activated upon choice, which we list below.
Limit to the number of publications The number of publications is limited to a fixed proportion $$\epsilon < 1$$ of submissions. If the referee process produces too many accepted papers given the current editorial policy of the editor, then all accepted contributions are ranked according to editorial reputation $$REP_i^E$$ of the authors and only the first $$\epsilon N$$ papers are published. In scientific practice, journal rejection rates vary largely between journals and disciplines. Rejection rates might be lower in the physical sciences and larger in the social sciences and humanities (Zuckerman and Merton 1971; Hargens 1988). In most reported simulations, we opted for a more conservative value of $$\epsilon =0.3$$ that is closer to the latter. We varied the publication rate from zero to hundred percent in additional simulation runs (reported in the “Results” section, Figs. 45, 6).
Journal impact factor In recognition of the fact that publishing in a reputed journal produces a payoff that depends also on the quality of past published papers, agents who publish a paper may receive an increase to their payoff equal to:
\begin{aligned} JIF_t=\kappa \cdot \frac{\sum _{\tau =1}^t \sum _{i=1}^N GP_{i}^{\tau }}{\sum _{\tau =1}^t \sum _{i=1}^N GP_{i}^{\tau } + \sum _{\tau =1}^t \sum _{i=1}^N BP_{i}^{\tau }} \end{aligned}
(4)
At each given time step t, the public good benefit of journal impact factor (JIF) is given to all authors who get their papers published, irrespective of quality. That is, a public good bonus is added to the payoff of each agent publishing a paper. The size of the public good is proportional to the performance of the journal in terms of the proportion of high-quality papers published up to that point in time. The higher the proportion of good papers, the higher the JIF is. Note that the introduction of JIF increases payoffs for publications produced at high effort, but increases free rider rewards for those who are able to publish low-quality work to the same extent. We assume that the journal impact factor is a public good for those who published with a linear production function, where the increment $$\kappa \ge 1$$ describes the public value of a single scientific contribution. The lack of a journal impact factor and a linear public good with $$\kappa \le 1$$ describes a situation that is worse than the Prisoner’s Dilemma: even full cooperation does not compensate for the entailed costs. Considering the journal impact factor and $$\kappa >1$$, translates the game into a true linear Public Good Game, which is still extremely difficult to solve. In the illustrative runs, we fix $$\kappa =2$$, but we show in the robustness checks reported in Fig. 15 in the “Appendix” that our results do not change as long as JIF actually is a true public good multiplier ($$\kappa >1$$).
Desk-rejections and speeding up publication With increased time-pressure and burden of reviewers, it is common practice that not all submissions are sent out for review. Some submissions are desk-rejected and others have an easy, speedy route for publication. Editorial decisions behind this behaviour are very much based on the reputation of authors. We implement desk-rejection and desk-acceptance as an additive feature compared to the baseline model.
Desk-rejection and acceptance introduces a bias in favour of individuals with higher reputation and in damage of individuals with lower editorial reputation compared to the baseline model. Essentially, we introduce the possibility for the editor to desk-reject or accept submissions proportional to the relative editorial reputation of the author, regardless of recommendations by referees. Please note that as producing low or high-quality reviews is also part of editorial reputations, in this way, reviewers receive some compensation for their low or high reviewing efforts. The rule added to editorial decisions is as follows:
• Compute the minimal editorial reputation $$min(REP_i^E)$$, the maximal editorial reputation $$max(REP_i^E)$$ and the median editorial reputation $$median(REP_i^E)$$ of agents.
• If $$REP_i^E<median(REP_i^E)$$, then with probability
\begin{aligned} P_{dr}=\frac{REP_i^E - min(REP_i^E)}{median(REP_i^E)-min(REP_i^E)} \end{aligned}
(5)
the paper is sent out for review, and with probability $$1- P_{dr}$$, it is desk-rejected.
• If $$REP_i^E>median(REP_i^E)$$, then with probability:
\begin{aligned} P_{da}=\frac{REP_i^E - median(REP_i^E)}{max(REP_i^E)-median(REP_i^E)} \end{aligned}
(6)
the paper is desk accepted, and with probability $$1- P_{da}$$, it is sent out for review.
## Results
### Baseline results
We first demonstrate that in the baseline model in which scientists face costs for producing high-quality manuscripts and costs for producing high-quality reviews, there is almost no chance of any cooperation. This is not surprising, because low effort in writing papers as well as low effort in writing reviews is the dominant strategy in the baseline game. Figures 1 and 2 report that this is the case both for double blind and for single blind peer review systems considering a neutral editorial policy (AP).Footnote 5 In all cases, the strategy implying the production of low quality papers and reviews (dD) overtakes the entire population. To examine the failure of the scientific peer review process more closely, consider that high-quality review does not return any benefits, therefore every reviewer is better off by choosing D. In a population with only dD and cD strategies, dD yields higher average payoffs since, if people review randomly, there is a 50 % chance of getting a low-quality paper published, which is exactly the same for high-quality submissions. As cD strategies do not benefit anything from peer review and they entail higher costs for the author; they die out. Without any feedback loop that would help to ensure the production of scientific quality, science ends up as an empty exercise.
Baseline with reputation-weighted consideration of reviews Figures 1 and 2 contain also cases in which the editorial policy takes into account the editorial reputations of reviewers and attach higher weights to the opinion of higher reputed referees. These are editorial policies MR and ER. The strategy dD still gains overwhelming dominance under these policies. This is because such policies do not ensure the occurrence of correlated equilibria: the larger weight to opinions does not mean at all that these opinions would favor high-quality contributions more than others. Low effort in reviewing is a dominant strategy for every author. The opinion of those who started with cooperation receive higher weights, but they still underscore defectors with regard to payoffs. The initial population that is equally divided among different types of strategies goes through a quick and progressive elimination of cooperative strategies. In this process, having a relatively bad reputation does not matter for payoffs as the chances of publishing a paper become equivalent for good and bad papers over time.
Baseline with the entry of reputational concerns Somewhat surprisingly, the editorial policy that ensures a low, but stable level of cooperation is 1P. This is an editorial policy, which accepts all papers, if there is at least one positive recommendation from the reviewers. The surprising result originates in the lack of cooperation of reviewers. When reviewer recommendations are random, it should not matter from the quality point of view, how many reviewers have suggested the given manuscript for publication. In case of two reviewers and editorial policy AP, both reviewers need to recommend publication, which will happen in approximately 25% of the cases. This is within the limits for publication ($$\epsilon =0.3$$), hence the editor does not need to rely on individual reputations.
As there is a constraint on how many papers can be published, in case of random reviews, the friendly 1P editorial policy allows—in principle—publication of approximately 75 % of the submissions. In case of a surplus, the editor ranks the papers based on the editorial reputation of authors. Hence, a direct feedback on reputation exists, which is sufficient to guarantee in some simulation runs a stochastic mixed strategy equilibrium with the survival of cooperation.
### Reputational concerns and increased publication rate
We varied the publication rate from zero to hundred percent in additional simulation runs for editorial policies MR and 1P, using both single and double blind reviews. For the MR case, we did not find any significant differences compared to the baseline cases (Fig. 4) in line with what discussed in the previous section. Irrespectively of the publication rate, the dD strategy has overwhelming success: scientists place low effort in their reviews as well as in their work.
Again, the mild editorial policy 1P provides the better avenue for high efforts in writing papers. For the editorial policy 1P, we found a higher level of cooperation by increasing acceptance rate (Figs. 5, 6). That is, with the increase of journal space, simulations were more likely to end with a success of the cD strategy. Scientists place high effort in their work under conditions when it was easier to get it published. This is a very important result: cooperation is established with a “mild” editorial policy and in a “mild” environment more likely than in the case of strict editorial policy and a competitive environment.
The surprising result originates from the role of rejections in the editorial reputation calculation. When nearly all papers are published, the true qualities of nearly all papers are revealed. Bad papers written with low effort result in a loss of editorial reputation, which weighs largely for scientists’ publication chances. The power of publicity is not there in a competitive environment where $$\epsilon$$ is lower. Given the random reviewer recommendations, good papers are rejected just as likely as bad papers and therefore imply costly rejections for high effort authors. Hence, under such circumstances, low effort in writing papers is the ultimate beneficial strategy.
### Reputation bias in editorial policy
As we demonstrated, accounting on reputation of reviewers for making judgment on manuscripts is insufficient to trigger the production of high-quality reviews and high-quality papers. We shall see if a more direct consideration of editorial reputation leads to higher efforts and as a result to better science. Note that the model extension in this direction is related intentionally to popular discussions whether editors should be unbiased or they could rely on reputation signals of authors from the past. Should they catalyze the Matthew effect in science, in which the successful get even more success (Merton et al. 1968; Squazzoni and Gandelli 2012)? Should they contribute to the maintenance of the old-boyism bias? If they do, does it hurt or help scientific development?
Let us first introduce an editorial bias in favour of authors with high $$REP_i^E$$ and against authors with low one.Footnote 6 We assume that authors with an editorial reputation lower than the median has a chance of desk rejection that is in negative linear association with their reputation (Eq. 5). Similarly, we assume that authors with an editorial reputation higher than the median has a chance of desk acceptance that increases linearly with their reputation (Eq. 6). This modification does not rule out peer review, but concentrates its decisive character to the middle range, where no clear reputational judgment can be expected from the editor.
Results with this extension show no major breakthrough for cooperation: dD dominates the outcomes (Fig. 7). Either with double blind or single blind peer review, all agents become of dD types. This indicates that a direct editorial bias in desk acceptance and rejection in itself is insufficient to trigger a large extent of cooperation. This kind of editorial bias, however, is able to support the survival of conditional cooperation of reviewers (Fig. 8). When a strict editorial acceptance policy is applied (AP), the lack of publishable material leads to the need of selecting submissions based on reputation. The high effort in producing scientific material, however, does not pay off because of the difficulties of acceptance. Scientists therefore follow the easier path of gaining higher reputation and might place high effort in reviewing others. Reviewing efforts are profitable when they are most likely to provide reputation benefits. The public reputation helps the referees to get the best out of their reputation-based conditional strategy: when the public reputation of an author $$REP^P_i$$ is high, then it is more likely that his paper gets published, and therefore it is more likely that a review of high quality will ensure positive returns in terms of editorial reputation. As a result, the cooperative reviewer strategy that is conditional on the reputation of the author might survive in case of single blind peer review. This happens because the editor might provide a differential treatment for individuals with higher reputations earned strictly by high-quality reviews. At the opposite, when the author’s reputation is low, then reviewers with a strategy conditional on author reputation do not bother and follow the cheap strategy of providing random advice. In this case, their payoff is not different from agents who never put high effort in reviewing.
### Introducing the public good of journal impact factor (JIF)
Large public good benefits in the presence of some reputational motives allow for strategies producing high quality papers to survive and disseminate (Fig. 9). Furthermore, the analysis of the population evolution shows that when JIF is active, most strategies producing low-quality papers disappear from the population. This means that if a journal publishes high-quality papers, it ensures that future submissions will also be of high quality.
This is good news given the fact that the public good reward of JIF as a payoff supplement does not erase the social dilemma structure of the game. Defection is still the best reply strategy both for authors and for reviewers. Still, cooperation evolves; thanks to the editorial account of author reputations and to the large initial share of cooperative strategies that survive the early phase of the simulation. Full cooperation is among those who disappear relatively late (Fig. 9), which assists the dominance of the high-effort-in-writing and low-effort-in-reviewing strategy. As a consequence, the rise of good papers at the end is not accompanied by good reviews (see Fig. 10 for a statistical assessment). Still, the scientific development is maintained and results in the highest possible JIF. This means that only high quality papers are published. Peer review just adds a random noise for the publication process and it is meaningless anyway because everyone contributes with high-quality submissions.
Journal impact factor together with strong reputation concerns Public good rewards that supplement the original payoff structure largely improve the opportunities for scientific development and lead to the overall success of the cD strategy. We have also seen that under certain editorial policies that take account of reputation, a low level of full cooperation (cC) can be sustained also without the public good reward. When we introduced desk rejections and acceptance based on reputation to the baseline, then some agents gained reputation successfully with a conditional reviewing strategy dRep. It is therefore interesting to observe which strategies are successful if both JIF and strong reputation concerns are accounted for.
The results show that the strongest determinant of the evolution is the journal impact factor (Figs. 11, 12). When it matters, even under strong reputation concerns, high-effort publication strategies gain dominance with low-effort reviews. This is very much meaningful once there is a reward for reputation and the most reputational gains can be obtained by high-quality publications.
Tacit agreements To complete the story, we still miss a mechanism that makes reviewing as well as writing papers plausible and sustainable without radically altering the payoff structure of the game. A realistic possibility is to consider “tacit agreements” that are based on direct reciprocity and might work better in case of single blind reviews, in which at least one side of the informational asymmetry is relaxed. “Tacit agreements” work against the impartiality of peer review in practice. A “nice” tacit agreement strategy could start with high effort in the first n rounds, then recognize previous reviewers of own papers with p probability and retaliate them not with high effort/low effort, but with acceptance/rejection recommendation. Once there is a coordination device that brings high quality submissions in the hand of highly reputed reviewers, then acceptance recommendations would match true quality. In this case, the editorial selection policy will matter, because this would create the possibility of low cost reciprocation for high performing scientists. This is in line with the conclusion of similar empirical and simulation work (such as Bianchi et al. 2017). Some scientists believe that top researchers in top journals are involved in such reciprocity. It is important to note the possible drawbacks of such self-emerged network-based practices, including old-boyism, partiality, and the conservative bias (Sarigöl et al. 2014; Sobkowicz 2015; Soós et al. 2015).
## Conclusion
It is puzzling why scientists devote considerable time and effort for writing reviews that decreases their time spent on their own research. Once everyone acts according to self-interest, reviews are all of low effort and they cannot be adequately used to judge scientific quality. As a consequence, scientists submit low quality work in the hope of passing through randomly judging reviewers. Still, in practice, reviewers as well as authors invest high effort in reviews and submissions. We have labeled this puzzle as the miracle of peer review and scientific development. We investigated some potential mechanisms that might resolve the puzzle in an agent based model.
We have modeled scientific production accordingly: with an incentive structure in which low effort in writing papers as well as in writing reviews is the dominant strategy of agents. We applied a replicator dynamics rule to the population of scientists, allowing for the reproduction of strategies that result in higher payoffs. Not surprisingly, in our baseline model, low effort in writing papers as well as in writing reviews have spread in the population and scientific practice has become an empty exercise.
Next, we assumed that editors might rely on the reputations of authors in their choices. In our model with a single journal, the editor took perfect account of high- and low-quality publications of authors, the number of their rejected papers, and if their reviewer recommendations were in line with the true quality of the paper or not. We examined different editorial policies that took account of the reputations of scientists. We showed that if reputations are used in editorial assessment of reviewers’ suggestions, then it does not save science from low quality submissions and low quality reviews. A bit more surprisingly, easing the route for publication by desk acceptance for highly reputed authors alone has not changed anything either. All this indicated that the emergence of cooperation in the form of high efforts is a difficult motivational puzzle.
Some cooperation has resulted from a friendly editorial policy that categorized submissions as publishable if at least one reviewer recommended publication. This policy led to an oversupply of publishable material, which called for the ranking of submissions based on author reputations. This direct feedback has made the investment in reputations profitable. Consequently, high-effort author strategies survived in a mixed equilibrium together with low-effort author strategies, but nobody invested effort in reviewing.
Some cooperation has emerged also when a strict editorial acceptance policy was applied, in which only papers with unanimous reviewer support are published. In this case, however, the lack of publishable material was responsible for the worth of reputation. As the investment in reputation via writing papers was risky due to the difficulties of publishing, scientists profited more from the investment in reputation via reviews. A strategy that conditioned high reviewing efforts on the author’s reputation was able to gain a notable share in the population.
Reputations worked to some extent, but public good benefits were clearly better catalysts of scientific development. Once we introduced the journal impact factor as a public good benefit, which meant the distribution of an additional payoff for all authors who published in the journal (either a good or a bad paper), cooperation has become the most successful strategy of authors. In this case, editorial reputations became correlated with actual contributions to the provision of the pubic good. But as the production of high quality papers was still much more important for reputations than high quality reviews, the cooperative strategy that emerged as successful was investing high effort only in manuscript writing and not in reviewing. As a consequence, cooperation has been observed in scientific production, but peer review has just added random noise to this development, which raises doubts of its use (in line with Neff and Olden 2006) and concerns about the use of public money for this activity.
At the end, we were successful in demonstrating in a simple model the puzzling motivational problem of peer review. We highlighted that it is not easy to find the way out of this puzzle. We showed that a high value of the public good of science maintains scientific development. Reputational systems that are heavily building on author contributions might be partially sucessful, especially if the reputational hierarchy is directly used for selecting between similarly rated submissions. These mechanisms, however, will not help to sustain the efficiency of peer review. Paradoxically, mechanisms that are able to induce some level of high-quality reviews are building on reciprocity. In practice, they are often associated with partiality, old-boyism, the emergence of invisible colleges, the Matthew effect, the conservative bias, and the stratification of science.
Future work should extend our simple model towards studying multiple journals that compete for success with each other. This extension would allow for the evolution of editorial strategies in a straightforward way and in parallel to theoretical studies that highlight how group selection can ensure higher cooperation (Traulsen and Nowak 2006; Nowak 2006), is expected to lead to better reviewer performance. Our current study and subsequent research on the social dilemma of peer review might help us to understand how the evaluation system of scientific work can be sustained. Once the fundamental mechanisms are studied rigorously, they can also lead to policy recommendations on improvements of the current system and the design of new solutions (cf. Paolucci and Grimaldo 2014). | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 2, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.679894745349884, "perplexity": 1658.314112421529}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446710953.78/warc/CC-MAIN-20221204004054-20221204034054-00824.warc.gz"} |
http://export.arxiv.org/abs/2012.09193 | gr-qc
(what is this?)
# Title: Exploring Axial Symmetry in Modified Teleparallel Gravity
Abstract: Axially symmetric spacetimes play an important role in the relativistic description of rotating astrophysical objects like black holes, stars, etc. In gravitational theories that venture beyond the usual Riemannian geometry by allowing independent connection components, the notion of symmetry concerns, not just the metric, but also the connection. As discovered recently, in teleparallel geometries, axial symmetry can be realised in two branches, while only one of these has a continuous spherically symmetric limit. In the current paper, we consider a very generic $f(T,B,\phi,X)$ family of teleparallel gravities, whose action depends on the torsion scalar $T$ and the boundary term $B$, as well as a scalar field $\phi$ with its kinetic term $X$. As the field equations can be decomposed into symmetric and antisymmetric (spin connection) parts, we thoroughly analyse the antisymmetric equations and look for solutions of axial spacetimes which could be used as ans\"atze to tackle the symmetric part of the field equations. In particular, we find solutions corresponding to a generalisation of the Taub-NUT metric, and the slowly rotating Kerr spacetime. Since this work also concerns a wider issue of how to determine the spin connection in teleparallel gravity, we also show that the method of "turning off gravity" proposed in the literature, does not always produce a solution to the antisymmetric equations.
Comments: 26 pages, 1 figure. Matches published version in PRD Subjects: General Relativity and Quantum Cosmology (gr-qc) Journal reference: Phys. Rev. D 103, 044058 (2021) DOI: 10.1103/PhysRevD.103.044058 Cite as: arXiv:2012.09193 [gr-qc] (or arXiv:2012.09193v2 [gr-qc] for this version)
## Submission history
From: Sebastián Bahamonde Dr [view email]
[v1] Wed, 16 Dec 2020 19:00:04 GMT (72kb,D)
[v2] Thu, 25 Feb 2021 17:40:39 GMT (84kb,D)
Link back to: arXiv, form interface, contact. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.48707088828086853, "perplexity": 1190.56886456087}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-17/segments/1618038071212.27/warc/CC-MAIN-20210413000853-20210413030853-00158.warc.gz"} |
http://www.shsu.edu/~txcae/Powerpoints/prepostest/probability2postest.html | Probability
Post test
Use the following balls for questions 1 - 4.
1. What are the possible outcomes for these balls?
A. red, green, blue, yellow
B. red, blue, yellow
C. red, blue
D. red, yellow, purple, blue
2. Are all of the outcomes equally likely?
A. Yes
B. No
3. What is the probability of drawing a green ball?
A. 0/6
B. 3/6
C. 2/6
D. 1/6
4. What is the probability of drawing a blue ball?
A. 2/6
B. 3.6
C. 1/6
D. 4/6
Use the following spinner for question 5-8.
5. If you were to spin this spinner, what are the possible outcomes?
A. 1, 2, 3
B. 4, 5, 6
C. 2, 6, 8
D. 1, 7, 6, 8
6. Are all of the outcomes equally likely?
A. Yes
B. No
7. What is the probability of spinning an 8?
A. 2/4
B. 3/4
C. 1/4
D. 0/4
8. What is the probabilitty fo spinning a 7?
A. 2/4
B. 3/4
C. 1/4
D. 0/4
9. What are the possible outcomes when flipping a coin? | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9079200029373169, "perplexity": 2508.8599282200103}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-30/segments/1531676591837.34/warc/CC-MAIN-20180720213434-20180720233434-00595.warc.gz"} |
https://lavelle.chem.ucla.edu/forum/search.php?author_id=13308&sr=posts | ## Search found 33 matches
Sat Mar 16, 2019 11:31 am
Forum: Administrative Questions and Class Announcements
Topic: LYNDON'S PORK RAMEN REVIEW
Replies: 37
Views: 3529
### Re: LYNDON'S PORK RAMEN REVIEW
For number 9 part d do we have all the information we need to solve the problem? I'm assuming we will have to solve for the standard cell potential and find the difference between that and this new cell potential, I just don't know how to get there.
Thu Mar 14, 2019 4:41 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Review Session-Thermo-files- Wednesday-Q11-clarification [ENDORSED]
Replies: 10
Views: 837
### Re: Review Session-Thermo-files- Wednesday-Q11-clarification[ENDORSED]
Number 8 asks for the enthalpy change per mol so wouldn't you have to convert 2000g to moles of BaSo4 and then solve per mol?
Tue Mar 12, 2019 11:22 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Slow Step
Replies: 6
Views: 170
### Re: Slow Step
Given a rate law we could identify the slow step out of a list of steps because we know that it is the rate determining step so the law will be based ooff of its reactants.
Tue Mar 12, 2019 11:18 am
Forum: Method of Initial Rates (To Determine n and k)
Topic: Determining the rate constant when given trials
Replies: 3
Views: 199
### Re: Determining the rate constant when given trials
For this particular question, you are using ones where concentrations aren't all constant because on of the reactants is zero order and does not effect the rate law. As far as dividing things goes, that is just to show the ratio of the concentration in one reaction to that of another and then compar...
Tue Mar 12, 2019 11:11 am
Forum: First Order Reactions
Topic: first order intergrated rate laws
Replies: 2
Views: 138
### Re: first order intergrated rate laws
Most of the time when you are working with integrated rate laws it will be because a reaction happened over a specific amount of time with an initial and final concentration. You will be asked to solve for one of the variables given the others and will use the integrated rate law to solve for this c...
Tue Mar 05, 2019 11:07 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Galvanic Cells
Replies: 4
Views: 211
### Re: Galvanic Cells
Think of it like a battery being used up. After all of the reactants have gone to products, there is no more ability for it to create energy from the reaction.
Tue Mar 05, 2019 11:05 am
Forum: General Rate Laws
Topic: Order of Reaction
Replies: 6
Views: 254
### Re: Order of Reaction
Find the individual orders of each reaction based on how the rate changes with additional initial concentration of the reactants. Each reactant will have its own individual order and then you will take the sum of the orders of the reactants to find the overall order of the reaction.
Tue Mar 05, 2019 11:02 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Replies: 2
Views: 123
When thinking about the unique vs individual rate, I look at what Dr. Lavelle went over in class with one over the coefficient times the rate of change. Each species will have the same unique rate (one over coefficient times individual rate) but different individual rates if they have different coef...
Thu Feb 28, 2019 7:08 am
Forum: Balancing Redox Reactions
Topic: Acidic Solutions
Replies: 7
Views: 321
### Re: Acidic Solutions
Also, don't forget that adding hydronium ions adds electrons to that side when you are balancing the electrons later.
Thu Feb 28, 2019 6:52 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Order of Aqueous
Replies: 2
Views: 118
### Re: Order of Aqueous
It depends whether it is the cathode or the anode. You write the reactant first and then the product, so you would have to determine if it is the oxidation or reduction half reaction to determine the order.
Thu Feb 28, 2019 6:49 am
Forum: Balancing Redox Reactions
Topic: Basic Solutions
Replies: 3
Views: 165
### Re: Basic Solutions
I always start with balancing with H20 and then move on to OH- or H+. Makes it easier for me. The one that you use depends on the type of solution you are in, and balance other parts of the reaction before you start adding hydrogens and oxygens.
Fri Feb 22, 2019 11:41 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free energy
Replies: 5
Views: 238
### Re: Gibbs Free energy
Sometimes, if given enough values, you may have the use the equation PV=nRT to solve for temperature.
Fri Feb 22, 2019 11:38 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Delta G=0 at equilibrium
Replies: 4
Views: 431
### Re: Delta G=0 at equilibrium
Gibbs free energy is the energy free to do work. At equilibrium, no net energy is being gained or lost (nothing is really changing). Thus, at equilibrium, Delta G is 0.
Fri Feb 22, 2019 11:34 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Favor ability of Cell portential
Replies: 5
Views: 286
### Re: Favor ability of Cell portential
A positive cell potential means spontaneous, a negative cell potential means not spontaneous. Think of the equation Delta G = -nFE. Negative delta G is spontaneous, and n (electrons transferred) and F (Faraday's constant) are always positive. Thus the, the sign of E (cell potential) determines wheth...
Tue Feb 12, 2019 11:22 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy Change by Volume and Pressure
Replies: 2
Views: 115
### Re: Entropy Change by Volume and Pressure
No. You just pick one of the values and use it to solve for the change in entropy.
Tue Feb 12, 2019 11:19 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Isochoric vs isometric
Replies: 4
Views: 663
### Re: Isochoric vs isometric
Isochoric is constant volume, Isobaric is constant pressure, Isothermal is constant temperature. I don't think we have done any work with Isometric.
Tue Feb 12, 2019 11:14 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solids and Liquids in K expression
Replies: 2
Views: 163
### Re: Solids and Liquids in K expression
Balance your equation first and then omit the ones that are solids are liquids.
Sun Feb 10, 2019 11:22 pm
Forum: Administrative Questions and Class Announcements
Topic: Lyndon's HOTDOG MIDTERM REVIEW SESSION!! FINALLY!
Replies: 49
Views: 3852
### Re: Lyndon's HOTDOG MIDTERM REVIEW SESSION!! FINALLY!
You can solve for temp using PV=nRT. I keep getting a wack answer for this question, however. I'm assuming the overall delta U and delta S will be zero because they are state functions, but I am not getting the right q and w quantities. Can someone who feels confident put down their values so I can ...
Wed Feb 06, 2019 10:15 am
Forum: Phase Changes & Related Calculations
Topic: Heating Curve
Replies: 4
Views: 179
### Re: Heating Curve
Think of the heat capacity as the amount of heat something can absorb. The larger the value, the more heat it will be able to absorb before it transitions to the next phase. If it can absorb more heat,it will take longer for this process to happen and will thus have a less steep slope.
Wed Feb 06, 2019 10:12 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Constant Pressure Calorimeter
Replies: 5
Views: 465
### Re: Constant Pressure Calorimeter
Most calorimeters we work with should be isolated or closed systems. I don't think any of them will be open.
Wed Feb 06, 2019 10:07 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Midterm [ENDORSED]
Replies: 49
Views: 2042
### Re: Midterm[ENDORSED]
Homework problems as well as watching youtube videos on certain concepts has worked well for me. Professor Dave Explains on youtube has some good videos that explains concepts pretty clearly.
Tue Jan 29, 2019 9:58 pm
Forum: Phase Changes & Related Calculations
Topic: Internal Energy
Replies: 1
Views: 110
### Re: Internal Energy
I believe the kinetic portion has to do with the movement in all direction of a molecule of a substance and the potential portion has to do with the energy that held inside the bonds of that substance.
Tue Jan 29, 2019 9:47 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: HW Q
Replies: 2
Views: 122
### Re: HW Q
Basically, a change in, say, 10 degrees celsius is the same as a change in 10 Kelvin. So when you're using a value for change in temperature in the equation you can use celsius and Kelvin interchangeably.
Tue Jan 29, 2019 9:44 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Std enthalpy combustion
Replies: 1
Views: 47
### Re: Std enthalpy combustion
If we need to use that combustion reaction to solve for the enthalpy of a different net reaction, that value will be given to us. If we are asked to actually find the enthalpy of the combustion reaction we can use any of the methods to solve for enthalpy we learned in lecture. Either way, some value...
Thu Jan 24, 2019 4:45 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Tricks for identifying Strong/Weak Acids & Bases
Replies: 5
Views: 232
### Re: Tricks for identifying Strong/Weak Acids & Bases
Anytime we are given a Ka or Kb, the acid or base is almost certainly going to be weak. This is because the Ka or Kb of a strong acid or base is extremely high because the substance gets basically completely deprotonated/protonated. This should help you in identifying weak substances right away, and...
Thu Jan 24, 2019 4:39 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5% Rule and % Deprotonation
Replies: 3
Views: 166
### Re: 5% Rule and % Deprotonation
Just for future reference and ease on test problems, any time the constant value is lower than 1 x 10^-3 it should be safe to use an approximation. You can use the % deprotonation rule to check afterwards if you are worried, but this will save you some time on exams.
Thu Jan 24, 2019 4:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Autoprotolysis
Replies: 3
Views: 191
### Re: Autoprotolysis
I believe it is any value higher than 1 x 10^-7 that will make a difference in the PH.
Tue Jan 15, 2019 11:05 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6th edition Question 11.45
Replies: 2
Views: 77
### Re: 6th edition Question 11.45
Because the equilibrium constant of the decomposition of Cl2 is less than that of the decomposition reaction for F2, there are less products in the chlorine reaction than the fluorine reaction. This shows that the chlorine is more likely to keep its original form and not decompose as much, showing i...
Tue Jan 15, 2019 11:00 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Question on 12.41
Replies: 3
Views: 124
### Re: Question on 12.41
Also, in regards to the strengths of acids and bases based on their equilibrium constants, a lower Kx (Ka or Kb) shows a weaker substance. A lower Kx also responds to a higher PKx if those are the values you are looking at, so a higher PKx would be weaker.
Tue Jan 15, 2019 10:56 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Predict Solubility
Replies: 1
Views: 81
### Re: Predict Solubility
The higher the equilibrium constant is, the more the reaction favors the products and thus the more the compound is dissociated if it is reacting with water. This would represent a higher solubility.
Thu Jan 10, 2019 12:27 pm
Forum: Ideal Gases
Topic: Reaction Quotient
Replies: 5
Views: 227
### Re: Reaction Quotient
When you have a reaction that consists of only gasses, you use their partial pressures in the equation that we learned to find the Kp value. When the reaction consists of compounds in a non gas state (for instance aqueous) you would plug in the concentrations of the products and reactants into the s...
Thu Jan 10, 2019 12:23 pm
Forum: Ideal Gases
Topic: Identifying gases in equilibrium via pictures
Replies: 2
Views: 120
### Re: Identifying gases in equilibrium via pictures
This is because there is no change in the composition of the solution from flask 3 to 4. To simplify things, look at the number of ions stuck together and those floating around freely. As the pictures progress, more ions are floating around freely, but in flask 3 and 4 there are the same number of d...
Thu Jan 10, 2019 12:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Concentrations
Replies: 4
Views: 131
### Re: Equilibrium Concentrations
K is the value of the concentrations of the products over the reactants at equilibrium, thus we would only ever use equilibrium concentrations to find K. Any other concentrations we are given at a particular point in the reaction should be put into the same equation we have been practicing in class.... | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8451246023178101, "perplexity": 3174.6328149891538}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-45/segments/1603107902683.56/warc/CC-MAIN-20201029010437-20201029040437-00079.warc.gz"} |
http://openstudy.com/updates/51950b33e4b0d270317fad32 | ## Got Homework?
### Connect with other students for help. It's a free community.
• across
Online now
• laura*
Helped 1,000 students
Online now
• Hero
College Math Guru
Online now
Here's the question you clicked on:
55 members online
• 0 viewing
## Cookie_009 Group Title Divide and simplify completely. 8x - 8 x + 1 24 ______ * __________ / ______ x^2 - 1 6x^2 - 12x x^2 - 4 one year ago one year ago Edit Question Delete Cancel Submit
• This Question is Closed
1. eSpeX Group Title
Best Response
You've already chosen the best response.
1
Any time you divide fractions you are able to multiply by the inverse. I would suggest starting with your last term and invert so you can multiply to give you something like $\frac{8x - 8}{x^2 - 1}*\frac{x + 1 }{6x^2 - 12x}*\frac{x^2 - 4}{ 24}$ Then factor your terms so that you can cancel some terms before you start multiplying.
• one year ago
Best Response
You've already chosen the best response.
0
can you tell me what it is plzz
• one year ago
3. eSpeX Group Title
Best Response
You've already chosen the best response.
1
No, you wouldn't learn anything that way and the code of conduct for OS dictates that I help others learn and prohibits me from doing the work and providing an answer.
• one year ago
Best Response
You've already chosen the best response.
0
• one year ago
##### 1 Attachment
• Attachments:
## See more questions >>>
##### spraguer (Moderator) 5→ View Detailed Profile
23
• Teamwork 19 Teammate
• Problem Solving 19 Hero
• You have blocked this person.
• ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9812851548194885, "perplexity": 6244.799160568415}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-23/segments/1405997877693.48/warc/CC-MAIN-20140722025757-00120-ip-10-33-131-23.ec2.internal.warc.gz"} |
https://www.studyadda.com/sample-papers/neet-sample-test-paper-50_q60/431/331688 | • # question_answer If $\Delta {{H}_{f}}$ of ${{C}_{2}}{{H}_{4}}$ and ${{C}_{2}}{{H}_{6}}$ are ${{x}_{1}}\,and\text{ }{{x}_{2}}$ $Kcal\text{ }mo{{l}^{-1}}$, then heat of hydrogenation of ${{C}_{2}}{{H}_{4}}$ is- A) ${{\text{x}}_{1}}+{{x}_{2}}$B) ${{x}_{1}}-{{x}_{2}}$C) ${{x}_{2}}-{{x}_{1}}$ D) ${{x}_{1}}+2{{x}_{2}}$
$~{{C}_{2}}{{H}_{4}}\,\,+\,\,{{H}_{2}}\,\,\to \,\,{{C}_{2}}{{H}_{6}}$ $\Delta H=\left( \sum :H_{f}^{0} \right)-{{\left( \sum H_{f}^{0} \right)}_{R}}$ $=\left( {{x}_{2}} \right)-\left( {{x}_{1}} \right)$ | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9629408717155457, "perplexity": 4006.885562053717}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-43/segments/1570987823061.83/warc/CC-MAIN-20191022182744-20191022210244-00121.warc.gz"} |
https://k12.libretexts.org/Bookshelves/Science_and_Technology/Measurement/03%3A_Measurement_Systems_and_Unit_Conversion/3.03%3A_Convert_Units_of_Length_Weight_and_Capacity/3.3.06%3A_Convert_Using_Unit_Analysis | # 3.3.6: Convert Using Unit Analysis
$$\newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} }$$ $$\newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}}$$$$\newcommand{\id}{\mathrm{id}}$$ $$\newcommand{\Span}{\mathrm{span}}$$ $$\newcommand{\kernel}{\mathrm{null}\,}$$ $$\newcommand{\range}{\mathrm{range}\,}$$ $$\newcommand{\RealPart}{\mathrm{Re}}$$ $$\newcommand{\ImaginaryPart}{\mathrm{Im}}$$ $$\newcommand{\Argument}{\mathrm{Arg}}$$ $$\newcommand{\norm}[1]{\| #1 \|}$$ $$\newcommand{\inner}[2]{\langle #1, #2 \rangle}$$ $$\newcommand{\Span}{\mathrm{span}}$$ $$\newcommand{\id}{\mathrm{id}}$$ $$\newcommand{\Span}{\mathrm{span}}$$ $$\newcommand{\kernel}{\mathrm{null}\,}$$ $$\newcommand{\range}{\mathrm{range}\,}$$ $$\newcommand{\RealPart}{\mathrm{Re}}$$ $$\newcommand{\ImaginaryPart}{\mathrm{Im}}$$ $$\newcommand{\Argument}{\mathrm{Arg}}$$ $$\newcommand{\norm}[1]{\| #1 \|}$$ $$\newcommand{\inner}[2]{\langle #1, #2 \rangle}$$ $$\newcommand{\Span}{\mathrm{span}}$$$$\newcommand{\AA}{\unicode[.8,0]{x212B}}$$
## Conversion Using Unit Analysis
Munni and Caras were excited about their upcoming whale-watching trip. They did their research and discovered that some whales can weigh up to 150 tons. Munni’s home scale said that he weighed 120. Munni told everyone that he weighed only 30 pounds less than a whale. Was he correct?
In this concept, you will learn to use proportions and unit analysis.
### Using Proportions and Unit Analysis
A proportion is created when two ratios are found to be equivalent or equal.
1/2=3/6 is a proportion.
A unit rate is a comparison of two measurements, one of which has a value of 1.
55 miles/1 hour is a unit rate.
A unit scale is a ratio that compares the dimensions of an actual object to the dimensions of a scale drawing or model that represents the actual object.
1 inch/11 feet is a unit scale.
A standard unit is one that is most commonly used.
Both the customary and metric systems of measurement include weight (or mass), length, and liquid volume standard units.
Some examples are:
Customary standard weight: 16 ounces = 1 pound
Metric standard length: 1 meter = 100 centimeters
Customary standard liquid: 4 quarts = 1 gallon
These are called conversion factors and can be defined as the ratio of a measurement in one unit to the equivalent numerical value in another unit.
The ratio for ounces to pounds is 16:1 or 16 ounces/1 pound.
Standard units of measurement and proportions can be used to convert one unit of measurement to another. The process of converting one unit to another is called unit conversion. Units can be converted by using proportions, setting ratios equal to one another, or by unit analysis, multiplying times a standard unit of measure.
Here is an example using proportions.
A pitcher holds 4 liters of water. Determine how many milliliters of water the pitcher holds. Use the unit conversion: 1 liter = 1000 milliliters
First, write the unit conversion as a fraction.
1 liter/1000 millimeters
Next, write a ratio that compares the unit as it is given to the unknown converted unit.
Remember that a ratio standing alone can be written with either value in the numerator or denominator, but once it is used in a calculation, it must be formatted accordingly.
Unit to be converted = from 4 liters to x milliliters
This could be written as 4 liters/x millimeters or x millimeters/4 liters.
Then, write a proportion using the correct format. When writing a proportion, the units must be consistent.
1 liter/1000 milliliters=4 liters/x milliliters is correct.
Next, solve by cross multiplication.
x=4000
The answer is x = 4,000 ml.
Another way to solve the same problem is to use unit analysis.
First, write the unit conversion as a fraction.
1 liter/1000 milliliters or 1000 milliliters/1 liter
Next, write a ratio for the unit to be converted.
4 liters/1
When using unit analysis, the correct format will be such that after multiplication, the “from” units will cancel, and the answer will equal the “to” units.
4 liters/1 × 1000milliliters/1 liters
Then, cancel liters, and multiply.
4×1000 ml/1×1=4000 ml
### Examples
Example 3.3.6.1
Earlier, you were given a problem about Munni and Caras, who are going on a whale-watching trip.
Munni said a whale that weighed 150 tons was only 30 more than his weight of 120. Munni forgot the whale’s weight was in tons, and his was in pounds. Find the whale’s weight in pounds.
Solution
First, write the unit conversion as a fraction.
2000 pounds/1 ton
Next, write a ratio that compares the unit as it is given to the unknown converted unit.
x pounds/150 tons
Then, write a proportion making sure that the units are consistent.
2000 pounds/1 ton=x pounds/150 tons
Next, solve by cross multiplication.
x=300,000 pounds
The answer is the whale weighs 300,000 pounds.
Example 3.3.6.2
How many milliliters are there in 2.5 liters? Write a proportion and solve.
Solution
First, write the unit conversion as a fraction.
1 liter/1000 milliliters
Next, write a ratio that compares the unit as it is given to the unknown converted unit.
2.5 liters/x milliliters
Then, write a proportion making sure that the units are consistent.
1 liter/1000 milliliters=2.5 liters/x milliliters
Next, solve by cross multiplication.
X=2500 ml
The answer is x = 2,500 ml
Example 3.3.6.3
How many meters in 11 kilometers? Write a proportion and solve.
Solution
First, write the unit conversion as a fraction.
1000 m/km
Next, write a ratio that compares the unit as it is given to the unknown converted unit.
x m/11 km
Then, write a proportion making sure that the units are consistent.
1000 m/km=x m/11 km
Next, solve by cross multiplication.
X=11,000 m
The answer is x = 11,000 m
Example 3.3.6.4
How many inches are there in 18 feet? Use unit analysis.
Solution
First, write the unit conversion as a fraction.
12 inches/1 foot
Next, write a ratio for the unit to be converted.
18 feet/1
Then, cancel units, and multiply.
(12 inches/1 foot)×(18 feet/1)=216 inches
The answer is 18 feet = 216 inches.
Example 3.3.6.5
Convert 3 gallons to cups.
Solution
First, choose a method.
Since there is more than one standard unit between gallons and cups, setting up one proportion is not possible without intermediate steps. Use unit analysis.
First, write the unit conversions from gallons to cups as fractions.
1 gallon/4quarts 1 quart/2 pints 1 pint/4 cups
Next, write a ratio for the unit to be converted.
3 gallons/1
Then, set up a multiplication problem being sure to cancel unwanted units.
(3 gallons/1)×(4 quarts/1 gallon)×(2 pints/1 quart)×(4 cups/1 pint)
Next, cancel units and multiply.
(3×4×2×4 cups)/(1×1×1×1)=96 cups
The answer is 3 gallons = 96 cups.
### Review
Use unit analysis to solve each problem.
1. How many feet in 1 mile?
2. How many feet in 18.5 miles?
3. How many milliliters in 3.75 liters?
4. How many milliliters in 18.25 liters?
5. How many pounds in 3 tons?
6. How many pounds in 2.5 tons?
7. How many pounds in 4.75 tons?
8. How many feet in 18 yards?
9. How many inches in 4 feet?
10. How many inches in 8.75 feet?
11. How many milliliters in 29.5 liters?
Solve each problem.
1. Fred needs to buy vanilla extract to bake a cake. He could buy a 4-ounce bottle of vanilla extract for $8, or a 6-ounce bottle of vanilla extra for$15. Which bottle is the better buy?
2. A rope is 3 yards long. How many inches long is the rope? Use these unit conversions: 1 yard = 3 feet and 1 foot = 12 inches.
3. At the farmer's market, Maureen can buy 6 ears of corn for \$3. At that price, how much would it cost to buy 9 ears of corn?
4. James bought a 128-ounce bottle of apple juice. How many pints of apple juice did James buy? Use these unit conversions: 1 cup = 8 fluid ounces and 1 pint = 2 cups. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9190242886543274, "perplexity": 4156.619064584952}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030337398.52/warc/CC-MAIN-20221003035124-20221003065124-00046.warc.gz"} |
https://en.wikipedia.org/wiki/Dawson_function | # Dawson function
The Dawson function, $F(x) = D_+(x)$, around the origin
The Dawson function, $D_-(x)$, around the origin
In mathematics, the Dawson function or Dawson integral (named for H. G. Dawson[1]) is either
$F(x) = D_+(x) = e^{-x^2} \int_0^x e^{t^2}\,dt$,
also denoted as F(x) or D(x), or alternatively
$D_-(x) = e^{x^2} \int_0^x e^{-t^2}\,dt\!$.
The Dawson function is the one-sided Fourier-Laplace sine transform of the Gaussian function,
$D_+(x) = \frac12 \int_0^\infty e^{-t^2/4}\,\sin{(xt)}\,dt.$
It is closely related to the error function erf, as
$D_+(x) = {\sqrt{\pi} \over 2} e^{-x^2} \mathrm{erfi} (x) = - {i \sqrt{\pi} \over 2} e^{-x^2} \mathrm{erf} (ix)$
where erfi is the imaginary error function, erfi(x) = −i erf(ix). Similarly,
$D_-(x) = \frac{\sqrt{\pi}}{2} e^{x^2} \mathrm{erf}(x)$
in terms of the real error function, erf.
In terms of either erfi or the Faddeeva function w(z), the Dawson function can be extended to the entire complex plane:[2]
$F(z) = {\sqrt{\pi} \over 2} e^{-z^2} \mathrm{erfi} (z) = \frac{i\sqrt{\pi}}{2} \left[ e^{-z^2} - w(z) \right]$,
which simplifies to
$D_+(x) = F(x) = \frac{\sqrt{\pi}}{2} \operatorname{Im}[ w(x) ]$
$D_-(x) = i F(-ix) = -\frac{\sqrt{\pi}}{2} \left[ e^{x^2} - w(-ix) \right]$
for real x.
For |x| near zero, F(x) ≈ x, and for |x| large, F(x) ≈ 1/(2x). More specifically, near the origin it has the series expansion
$F(x) = \sum_{k=0}^{\infty} \frac{(-1)^k \, 2^k}{(2k+1)!!} \, x^{2k+1} = x - \frac{2}{3} x^3 + \frac{4}{15} x^5 - \cdots$,
while for large x it has the asymptotic expansion
$F(x) = \sum_{k=0}^{\infty} \frac{(2k-1)!!}{2^{k+1} x^{2k+1}} = \frac{1}{2 x} + \frac{1}{4 x^3} + \frac{3}{8 x^5} + \cdots$,
where n!! is the double factorial.
F(x) satisfies the differential equation
$\frac{dF}{dx} + 2xF=1\,\!$
with the initial condition F(0) = 0. Consequently, it has extrema for
$F(x) = \frac{1}{2 x}$,
resulting in x = ±0.92413887… (), F(x) = ±0.54104422… ().
$F(x) = \frac{x}{2 x^2 - 1}$,
resulting in x = ±1.50197526… (), F(x) = ±0.42768661… (). (Apart from the trivial inflection point at x = 0, F(x) = 0.)
## Relation to Hilbert transform of Gaussian
The Hilbert Transform of the Gaussian is defined as
$H(y) = \pi^{-1} P.V. \int_{-\infty}^\infty {e^{-x^2} \over y-x} dx$
P.V. denotes the Cauchy principal value, and we restrict ourselves to real $y$. $H(y)$ can be related to the Dawson function as follows. Inside a principal value integral, we can treat $1/u$ as a generalized function or distribution, and use the Fourier representation
${1 \over u} = \int_0^\infty dk \sin ku = \int_0^\infty dk \Im e^{iku}$
With $u=1/(y-x)$, we use the exponential representation of $\sin(ku)$ and complete the square with respect to $x$ to find
$\pi H(y) = \Im \int_0^\infty dk \exp[-k^2/4+iky] \int_{-\infty}^\infty dx \exp[-(x+ik/2)^2]$
We can shift the integral over $x$ to the real axis, and it gives $\pi^{1/2}$. Thus
$\pi^{1/2} H(y) = \Im \int_0^\infty dk \exp[-k^2/4+iky]$
We complete the square with respect to $k$ and obtain
$\pi^{1/2}H(y) = e^{-y^2} \Im \int_0^\infty dk \exp[-(k/2-iy)^2]$
We change variables to $u=ik/2+y$:
$\pi^{1/2}H(y) = -2e^{-y^2} \Im \int_y^{i\infty+y} du e^{u^2}$
The integral can be performed as a contour integral around a rectangle in the complex plane. Taking the imaginary part of the result gives
$H(y) = 2\pi^{-1/2} F(y)$
where $F(y)$ is the Dawson function as defined above.
The Hilbert transform of $x^{2n}e^{-x^2}$ is also related to the Dawson function. We see this with the technique of differentiating inside the integral sign. Let
$H_n = \pi^{-1} P.V. \int_{-\infty}^\infty {x^{2n}e^{-x^2} \over y-x} dx$
Introduce
$H_a = \pi^{-1} P.V. \int_{-\infty}^\infty {e^{-ax^2} \over y-x} dx$
The nth derivative is
${\partial^nH_a \over \partial a^n} = (-1)^n\pi^{-1} P.V. \int_{-\infty}^\infty {x^{2n}e^{-ax^2} \over y-x} dx$
We thus find
$H_n=(-1)^n {\partial^nH_a \over \partial a^n} |_{a=1}$
The derivatives are performed first, then the result evaluated at $a=1$. A change of variable also gives $H_a=2\pi^{-1/2}F(y\sqrt a)$. Since $F'(y)=1-2yF(y)$, we can write $H_n = P_1(y)+P_2(y)F(y)$ where $P_1$ and $P_2$ are polynomials. For example, $H_1=-\pi^{-1/2}y+2\pi^{-1/2}y^2F(y)$. Alternatively, $H_n$ can be calculated using the recurrence relation (for $n \geq 0$)
$H_{n+1}(y) = y^2 H_n(y) - \frac{(2n-1)!!}{\sqrt{\pi} 2^n} y$.
## References
1. ^ Dawson, H. G. (1897). "On the Numerical Value of $\int_0^h \exp(x^2) dx$". Proceedings of the London Mathematical Society. s1-29 (1): 519–522. doi:10.1112/plms/s1-29.1.519.
2. ^ Mofreh R. Zaghloul and Ahmed N. Ali, "Algorithm 916: Computing the Faddeyeva and Voigt Functions," ACM Trans. Math. Soft. 38 (2), 15 (2011). Preprint available at arXiv:1106.0151. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 49, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.992512583732605, "perplexity": 759.086556478925}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-32/segments/1438042988065.26/warc/CC-MAIN-20150728002308-00041-ip-10-236-191-2.ec2.internal.warc.gz"} |
https://math.stackexchange.com/questions/3354899/find-missing-dimensions-of-right-angle-triangle-connected-at-the-hypotenuse-of-a | # Find missing dimensions of right angle triangle connected at the hypotenuse of another triangle
Say you have a small triangle drawn on the hypotenuse of a larger right angle triangle. Would it be possible to find the missing dimensions on the large triangle? Knowing the dimensions of the small triangle, can you find the length of the missing side and the hypotenuse on the large triangle or is more information needed?
The image is not to scale, just for demonstration purposes. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.927573025226593, "perplexity": 228.2389992556862}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-10/segments/1581875145534.11/warc/CC-MAIN-20200221172509-20200221202509-00052.warc.gz"} |
https://aviation.stackexchange.com/questions/19669/why-doesnt-ge-replace-all-4-engines-for-on-their-flying-test-bed-instead-of-jus/19670 | Why doesn't GE replace all 4 engines for on their flying test bed instead of just 1?
GE (General Electric) flies Boeing 747s equipped with new engines that are being tested. Why can't they equip the test airplane with all 4 of the new engines? Wouldn't the thrust be imbalanced by replacing only 1 engine? As you can see, it may have 1 big engine and 3 smaller ones:
Other times, smaller engines are being tested. Would the smaller engine provide enough thrust for a large, heavy airplane like the 747?
• "on an airplane this size it wouldn't have much thrust because of the weight of the 747." I'm not sure this is what you meant to write. Thrust is not related to aircraft weight. I think you mean to ask if the lower thrust would cause performance problems (compared to the default engines). – egid Sep 4 '15 at 0:07
• Would the smaller engine provide enough thrust for a large, heavy airplane like the 747? It flies and GE were happy to fly it. That's probably all the answer you need to that one. – Simon Sep 4 '15 at 5:07
• Also note that these 747's are testbed aircraft: likely empty, and almost certainly running fairly low fuel loads. They aren't taking 14 hour passenger flights, so they aren't at maximum take off weight and don't need as much power as an in-service aircraft. – Jon Story Sep 4 '15 at 12:34
• It's perfectly legal to operate a 747 on only 3 engines for purposes of a ferry flight. The restrictions that apply are that it must be carrying no revenue payload and have aboard only the required crew. I would imagine the same rules apply for test flights. Thus there would be no problem operating with a smaller than normal engine thrust-wise. They would, of course, have reduced performance for a given weight. – Terry Sep 4 '15 at 21:27
They only change one, because that one is a new engine that is being tested.
If you are testing a new engine you change 1 at first so if it fails you have 3 others. If you change all 4 and there is a systematic defect in the design, now you have 0 good engines instead of 3.
You will also see that the test engine isn't always one suitable for a 747. This is because they may be testing a new design or a new alternative fuel and it is safer to test an unknown with 3 good engines (e.g. a 747) rather than with just 1 good engine (any two-engine airplane). This increases the safety margin if the test engine fails.
Running a different engine with a different thrust rating requires some thought about asymmetric thrust. Doing this on a 4-engine airplane simplifies this greatly over a 2-engine airplane. Ways to accommodate different thrust from the odd engine:
• De-rate the new engine so it only produces thrust equivalent to the normal engine
• Run the new engine at reduced thrust
• If the new engine is inboard, reduce the outboard engine thrust to balance the total yawing moment from that wing with the other side.
• Don't worry about it and trim the airplane to compensate.
The other advantage to doing this on a 747 is that a 4th engine is technically not really needed as a 747 can takeoff, fly and land with only 3 operating engines.
• Any idea how GE addresses the asymmetrical thrust? That's a good part of Ethan's question, although I imagine they just throttle back #3 to match #2. – egid Sep 3 '15 at 23:59
• @egid Yes. That's what I think they do. – curious_cat Sep 4 '15 at 8:41
• @egid derating would work, as would compensating loadout. Of course the 747 can handle a certain amount of asymmetric thrust without such measures quite well. – jwenting Sep 4 '15 at 8:53
• Possibly also worth mentioning that these testbed aircraft run fairly light, so there's no real need for 4 engines at all: as such, two engines running on partial power isn't much of an issue anyway and the "partner" engine can be safely throttled back – Jon Story Sep 4 '15 at 12:33
• @egid one way that they are doing that is having it as the inner engine, where too much/little thrust will have less lateral impact than if it was on the outside. Think of the lever arm that the engine thrust is affecting, outside engines have a longer arm than inner ones. – enderland Sep 4 '15 at 12:45
They are not testing that the engine works, that's already been proven with hundreds of hours of regulated and rigorous ground running. They are testing the "on wing" systems and behaviours in various flight conditions.
The on wing systems will also have been tested in ground runs before the first flight.
Therefore, only one engine is needed.
Although you already have a correct answer and it is accepted too but i would add another point to the mix. They are testing a new engine which uses a new technology and is uncertified/unproven. Why should they make 4 of that version and then find out a number of things to fix and go back to all 4 of them first before moving on to produce more models? That costs a lot of money and time.
One is enough.
Wouldn't the thrust be imbalanced?
Even on our R/C Aircrafts we can have different engine RPMs for different engines (on a multi engine model), let alone a Jumbo Jet! They can all operate at different turbine speeds and different thrust levels to balance as and when needed. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2894941568374634, "perplexity": 1533.9891532467902}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-18/segments/1555578721441.77/warc/CC-MAIN-20190425114058-20190425140058-00317.warc.gz"} |
http://jacac.deviantart.com/art/Postcard-from-Iceland-13-194757519 | Submitted on
January 24, 2011
Image Size
257 KB
Resolution
750×498
Thumb
Embed
Views
591
Favourites
56 (who?)
56
25
### Camera Data
Make
NIKON CORPORATION
Model
NIKON D300
Shutter Speed
10/3200 second
Aperture
F/9.0
Focal Length
13 mm
ISO Speed
200
Date Taken
Aug 9, 2010, 5:34:28 PM
Software
# Postcard from Iceland 13by JACAC
a n o t h e r . w a t e r f a l l . b u t . t h i s . o n e . g i v e . m e . a . c o m p l e t e . r a i n b o w . Gullfoss
### The Artist has requested Critique on this Artwork
Mar 17, 2014 Hobbyist General Artist
t h a n k . y o u .
Mar 18, 2014 Hobbyist General Artist
You're welcome.
Lindíssimo
o b r i g a d i s s i m o .
Beautiful. You manage to take color photos that express the same strong emotions that your black and white do.
w o w . n i c e . w o r d s
t h a n k . y o u . s o . m u c h
Amazing, beautiful composition!
i t ' s . t h e . n a t u r e . t h a t . i s . b e a u t i f u l . i . j u s t . w a s . t h e r e . a t . t h a t . t i m e . | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8835850954055786, "perplexity": 5484.955195903013}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-15/segments/1397609533308.11/warc/CC-MAIN-20140416005213-00217-ip-10-147-4-33.ec2.internal.warc.gz"} |
https://www.math.cuhk.edu.hk/~lzhang/ | Office: Room 237A, Lady Shaw Building - Map of Campus Map
Email: lzhang@math.cuhk.edu.hk
Phone: +852-3943-5139
Here is my CV
Here is my PhD thesis
Publications
1. The Homotopy Sequence for Nori's Fundamental Group .
Journal of Algebra, Vol. 393, pp. 79 - 91, doi: https://doi.org/10.1016/j.algebra.2013.07.010, 2013.
2. The Homotopy Sequence for the Algebraic Fundamental Group .
International Mathematics Research Notices, no.22, 6155-6174., doi: 10.1093/imrn/rnt163, 2014.
3. Nori's Fundamental Group over a non Algebraically Closed Field.
Annali della Scuola Normale Superiore di Pisa - Classe di Scienze, Vol. XVIII, pp. 1349-1394, doi: 10.2422/2036-2145.201604_007, 2018.
4. Algebraic and Nori Fundamental Gerbes (with Fabio Tonini).
Journal of the Institute of Mathematics of Jussieu,, no. 4, 855-897. doi: 10.1017/S147474801700024X, 2019.
5. F -divided sheaves trivialized by dominant maps are essentially finite (with Fabio Tonini).
Transactions of the American Mathematical Society, Volume 371, Number 8, 15 April 2019, Pages 5529-5549, doi: https://doi.org/10.1090/tran/7444, 2019.
6. Nori fundamental gerbe of essentially finite covers and Galois closure of towers of torsors (with M. Antei, I. Biswas, M. Emsalem, F. Tonini).
Selecta Mathematica, no. 2, Paper No. 18, 37 pp, doi: https://doi.org/10.1007/s00029-019-0449-z, 2019.
7. Essentially Finite Vector Bundles on Normal Pseudo-proper Algebraic Stacks (with Fabio Tonini).
Documenta Mathematica, to appear, https://arxiv.org/pdf/1702.03751.pdf.
Prepublications
1. Neukirch-Uchida Theorem for Purely Inseparable Field Extensions (with M. Romagny and F. Tonini).
https://arxiv.org/pdf/1711.06898.pdf.
2. A crystalline incarnation of Berthelot's conjecture and Künneth formula for isocrystals (with V. Di Proietto and F. Tonini).
https://arxiv.org/pdf/1812.05153.pdf.
3. A generalized Abhyankar's conjecture for simple Lie algebras in characteristic $$p>5$$ (with S. Otabe and F. Tonini).
https://arxiv.org/pdf/2003.03240.pdf.
Teaching
2019 summer, I taught a summer course Linear Algebra I
Summer semester 2018 I hold a student seminar on Quadratische Formen.
Winter semester 2017-2018 I taught a course on Crystals and Crystalline Cohomology.
Students
I have supervised a master student Ragnarsson Amazeen, here is his thesis.
Some Lecture Notes
1. An Introduction to $$\text{Bun}_G$$. (Forschungsseminar at FU-Berlin, June 1, 2017) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7913134098052979, "perplexity": 7705.004699722754}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-04/segments/1610703517966.39/warc/CC-MAIN-20210119042046-20210119072046-00171.warc.gz"} |
http://www.ck12.org/book/From-Vitamins-to-Baked-Goods%3A-Real-Applications-of-Organic-Chemistry/section/4.2/ | # 4.2: Background
Difficulty Level: At Grade Created by: CK-12
An alcohol is defined as a hydrocarbon with a hydroxyl (-OH) functional group. This group includes methanol, ethanol, propanal, butanol, and more.
\begin{align*}\mathrm{R}-\mathrm{OH}\end{align*}
Diagram of an alcohol molecule. The “R” represents the rest of the compound.
Alcohols are useful for many purposes because of their behavior in water. Alcohols are polar and capable of forming hydrogen bonds with water. The bond between the carbon and the oxygen is exceptionally strong, so the hydroxyl group cannot be removed by water and remains a part of the hydrocarbon. The more negatively charged oxygen will pull the hydrogen atoms in the water molecules towards it, causing the alcohol molecules to separate. For these reasons, most alcohols are soluble, or capable of dissolving, in water. This property is important to industry today, as about 55% of ethanol produced synthetically is used to create solvents.
Alcohol is soluble in both water and lipids, or fats. While the “-OH” end of the alcohol molecule is hydrophilic, or attracted to water, the hydrocarbon chain attached to it is hydrophobic, or repelled by water. The hydrocarbon chain is miscible in lipids and gives alcohol its fat-soluble properties.
Alcohols can act as either a base or an acid because they are capable of attracting and donating hydrogen ions (H+). They are generally slightly more basic than water and share many properties with other bases. For example, alcohols usually taste bitter and feel slippery.
When naming alcohols, start by counting the number of carbons in the compound and give it the correct prefix. Alcohols are distinguished from alkanes by adding “–anol,” instead of “-ane,” to the prefix. For all other compounds than methanol, specify which carbon the hydroxyl group is bounded to by following the IUPAC scheme.
### Notes/Highlights Having trouble? Report an issue.
Color Highlighted Text Notes
Show Hide Details
Description
Tags:
Subjects: | {"extraction_info": {"found_math": true, "script_math_tex": 1, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4669998586177826, "perplexity": 3339.079113331505}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-17/segments/1492917120001.0/warc/CC-MAIN-20170423031200-00248-ip-10-145-167-34.ec2.internal.warc.gz"} |
https://www.lessonplanet.com/teachers/worksheet-angles-6th-8th | # Angles
In this math worksheet, middle schoolers classify each angle as acute, right, obtuse, or straight. They also label each pair of lines as parallel, perpendicular, or intersecting.
Concepts
Resource Details | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8234789371490479, "perplexity": 6345.156721139164}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-51/segments/1575540528457.66/warc/CC-MAIN-20191210152154-20191210180154-00500.warc.gz"} |
http://georgeconk.blogspot.com/2011_07_21_archive.html | ## Thursday, July 21, 2011
### Atlantis lands ending the New Frontier
Atlantis has landed ending the manned space shuttle program.
When we had our first sputnik moment we were seized by fears - the Russians were smarter, at least definitely better at math. They were overtaking us. Some - like the ultra conservative Phyllis Shlafly - worked up hysterical claims that the Russians had nuclear bombs orbiting above us.
Americans were unnerved and intrigued by the prospect of space exploration. Rocket was the favorite word of the day. We were seized by a dream of exploration like that of the nineteenth century explorers - Lewis & Clark, Peary, Scott, Shackleton, and the triumphant Amundsen. John Kennedy tapped that spirit. The theme of his administration was the "new frontier" and we went to the moon. The shuttle was an attempt to routinize manned space flight. It didn't work out very well. There wasn't really very much to do up there, I guess. As we look back it is impossible to forget those who died in the effort, particularly Christa McAuliff the school teacher and the six others who died in the Challenger catastrophe. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8146593570709229, "perplexity": 10518.956430093926}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-15/segments/1397609539665.16/warc/CC-MAIN-20140416005219-00621-ip-10-147-4-33.ec2.internal.warc.gz"} |
https://www.physicsforums.com/threads/cross-sectional-area-young-modulus.462974/ | # Cross sectional area - Young Modulus
• Thread starter RCB
• Start date
• #1
29
0
out of interest does cross sectional area change when a force is applied (lets say I had a wire and I applied a force to it, the wire would stretch ) does its cross sectional area change
## Answers and Replies
• #2
PhanthomJay
Science Advisor
Homework Helper
Gold Member
7,171
509
Yes. During the stretching, the volume remains constant, so if the length increases, the area must decrease. Stretching a rubber band provides a good example of this. If the wire is steel, the stretch is relatively small under light loads, and thus the area reduction is small; as the load increases, then so does the elongation, and the reduction in area becomes significant beyond the wire's elastic limit as it approaches it's ultimate breaking strength.
• Last Post
Replies
3
Views
18K
• Last Post
Replies
2
Views
2K
• Last Post
Replies
1
Views
3K
• Last Post
Replies
2
Views
571
• Last Post
Replies
3
Views
11K
• Last Post
Replies
3
Views
5K
• Last Post
Replies
7
Views
26K
• Last Post
Replies
7
Views
25K
• Last Post
Replies
2
Views
981
• Last Post
Replies
17
Views
2K | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8060358166694641, "perplexity": 2901.173147475866}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-21/segments/1652662512229.26/warc/CC-MAIN-20220516172745-20220516202745-00599.warc.gz"} |
https://elycamrabeerfest.com/page-id201.php | # Color triangle physics
## Primary colours and secondary colours
Primary Colors
The colors that cannot be obtained by mixing any other colors in any proportions are called primary colors. The primary colors of light arered, green, and blue.These colors are also called basic colors of light. the reason for considering red, green and blue as primary colors is that all the other colors are made by mixing primary colors in suitable proportions. An interesting thing to be noted about primary colors is that when red, green and blue colors are mixed together they make white light.
Secondary Colors (Composite Colors)
The colors produced by mixing any two primary colors of light are called secondary colors or composite colors.Magenta, cyan and yellow colors are secondary colors.
Experiment for Formation of Secondary Colors
Take three torches and cover there glasses with red, green and blue cellophane papers, so as to produce red, green and blue light respectively. Now, switch on the torches and project all the three coloured lights on a white screen or wall, so that these coloured light may overlap. Now, you will observe that the area where red and green coloured lights overlap appears yellow. And the area where red and blue coloured lights overlap appears magenta. In the same way the area where blue and green coloured lights overlap gives cyan colour. Also, you will observe that the area where all the coloured lights overlap, appears white. We can also write these results as given below:
Red + Green = Yellow
Red + Blue = Magenta
Blue + Green = Cyan
Complementary Colors
Complementary colors are the two colors, which give white light when mixed together.For example, red and cyan are complementary colors because they produce white light on mixing together. In the same way, blue and yellow, and green and magenta are also complementary colors. The complementary colors can be easily remembered with the help of figure given below. The colors present exactly opposite to each other in the triangle are complementary colors.
Colour Triangle to show formation of secondary colors from primary colors
The use of complementary colors is also common in our daily life. The best example of it is the mixing of indigo in lime during white washing of buildings. Actually, with the passage of time the colour of buildings becomes yellowish. Because blue colour is complementary colour of yellow colour so mixing of indigo in lime during white washing keeps the buildings white for a long time.
Pigments
The chemicals which imparts colour to other bodies are called pigments.For example, human blood is red in colour due to the presence of heamoglobin pigment in it. in the same way, the colour of most plants is green due to the presence of chlorophyll pigment.
Sours: https://funscience.in/primary-colours-and-secondary-colours/
## Color triangle
arrangement of colors within a triangle
A color triangle is an arrangement of colors within a triangle, based on the additive combination of three primary colors at its corners.
An additive color space defined by three primary colors has a chromaticitygamut that is a color triangle, when the amounts of the primaries are constrained to be nonnegative.[1][2]
Before the theory of additive color was proposed by Thomas Young and further developed by James Clerk Maxwell and Hermann von Helmholtz, triangles were also used to organize colors, for example around a system of red, yellow, and blue primary colors.[3]
After the development of the CIE system, color triangles were used as chromaticity diagrams, including briefly with the trilinear coordinates representing the chromaticity values.[4] Since the sum of the three chromaticity values has a fixed value, it suffices to depict only two of the three values, using Cartesian co-ordinates. In the modern x,y diagram, the large triangle bounded by the imaginary primaries X, Y, and Z has corners (1,0), (0,1), and (0,0), respectively; color triangles with real primaries are often shown within this space.
### Maxwell's disc
Maxwell was intrigued by James David Forbes's use of color tops. By rapidly spinning the top, Forbes created the illusion of a single color that was a mixture of the primaries:[5]
[The] experiments of Professor J. D. Forbes, which I witnessed in 1849… [established] that blue and yellow do not make green, but a pinkish tint, when neither prevails in the combination…[and the] result of mixing yellow and blue was, I believe, not previously known.
— James Clerk Maxwell, Experiments on colour, as perceived by the eye, with remarks on colour-blindness (1855), Transactions of the Royal Society of Edinburgh
Maxwell took this a step further by using a circular scale around the rim with which to measure the ratios of the primaries, choosing vermilion (V), emerald (EG), and ultramarine (U).[6]
Initially, he compared the color he observed on the spinning top with a paper of different color, in order to find a match. Later, he mounted a pair of papers, snow white (SW) and ivory black (Bk), in an inner circle, thereby creating shades of gray. By adjusting the ratio of primaries, he matched the observed gray of the inner wheel, for example:[7]
To determine the chromaticity of an arbitrary color, he replaced one of the primaries with a sample of the test color and adjusted the ratios until he found a match. For pale chrome (PC) he found . Next, he rearranged the equation to express the test color (PC, in this example) in terms of the primaries.
This would be the precursor to the color matching functions of the CIE 1931 color space, whose chromaticity diagram is shown above.
• Drawing of Maxwell's color top
• A color triangle attributed to Fick in 1892, based on imaginary primaries corresponding to the three primary sensations of the human eye. In such a triangle, all real colors fall within the curved outline defined by the "pure sensations".
### References
Sours: https://en.wikipedia.org/wiki/Color_triangle
## A concept of primary colors [closed]
It's a common conception that there are at least three different colors which produce most of the visible spectrum.
I am wondering if there is a unique set of these "primary" colors which could be chosen as the best one.
For instance, what's the difference between the sets and and if I were to choose a better option, which one would I pick?
Series of comments pointed out that the question is not so clear.
Firstly, let's say that we're calling the human-visible spectrum (which is, more or less, defined (yet, empirically) between certain wavelengths) a .
Now, using terms , , , , etc. I mean the wavelengths (rather, localized wave packets around some wavelengths) commonly associated with these names. The names are not of any importance, really.
Addition of several combinations of localized wave packets (i.e. colors) are possible in different situations.
By I mean the event when a human mind cannot differentiate the superposition of the several wave packets from a single localized wave packet (lying at a, generally, different wavelength in the spectrum).
For instance, the perception of the superposition of $\lambda_1$, $\lambda_2$, $\lambda_3$,... wave packets (with known intensities, of course) can result into the same brain signals which are resulted from a single $\lambda$ wave packet (again, with some intensity).
1. Is this $\lambda$ unique? Meaning that for each human (excluding, maybe the colorblind ones) a predefined set of wavelengths and intensities would result to the same wavelength/intensity of the "mixed" color?
2. If I want to construct the most number of different wavelengths for these "mixed" colors (taking into account that the set is continuous, I'd talk about the greatest measure for the subsets of the visible color spectrum rather than "most number" of colors), a) what is the least number of finite wavelengths which could, by combining them with different intensities, obtain such a result? b) where do these finite wavelengths, most likely, reside in the visible spectrum?
(For instance, if you'd answer 3 colors: RGB, I would like to know why and if they can produce more colors than the RYB or some random choice of 3 different colors.)
$\endgroup$Sours: https://physics.stackexchange.com/questions/267549/a-concept-of-primary-colors
Coheed and Cambria - The Physics of Color Documentary
.
## Triangle physics color
.
The Physics and Psychology of Colour - with Andrew Hanson
.
### You will also like:
.
199 200 201 202 203 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4757879972457886, "perplexity": 1416.7930905097771}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-49/segments/1637964358480.10/warc/CC-MAIN-20211128073830-20211128103830-00340.warc.gz"} |
https://kusemanohar.info/2016/05/31/neural-network-as-universal-appropriators-intuitive-explaination/ | # Neural Network as Universal Approximators : Intuitive Explaination
Came across this wonderful explanation of why the neural network with hidden layer are universal approximators. Although not very helpful for practical purpose gives an intuitive feel of why neural network give reasonable results.
The basic idea is to analyze a sigmoid function as you change w and b . In particular effect on $\sigma( w\times x + b)$ as one varies w and b. It is been shown with an animation that two sigmoids sum can be seen as a step function in some space. Having multiple pairs of step function can be used to approximate a 1d function. Extension of this idea to 2D has also been shown.
See details here : http://neuralnetworksanddeeplearning.com/chap4.html | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 1, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7793759107589722, "perplexity": 598.6142915778146}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-21/segments/1620243989614.9/warc/CC-MAIN-20210511122905-20210511152905-00410.warc.gz"} |
https://socratic.org/questions/what-does-beta-decay-mean | Chemistry
Topics
What does beta decay mean?
May 3, 2016
The decay of a neutron into a proton.
Explanation:
$\beta$-decay is the decay of a neutron into a proton (or a proton into a neutron) with the release of an electron to conserve charge. It also releases a neutrino. This keeps the mass the same (neutrons and protons weigh about the same) but increases the atomic number by one.
$\beta$-decay happens when a nucleus has too many neutrons and is unstable.
Atomic number, $Z$, is the number of protons, and mass number $X$ is the total number of neutrons plus protons. In notation of element $A$ this is written as
""_ Z^XA
A theoretical example of $\beta$-decay using carbon-12 ($Z = 6 , X = 12$) would increase the atomic number by one to make nitrogen and keep the mass the same.
${\text{_ 6^12C->""_ 7^12N+}}_{-} {1}^{0} e$
Check this is correct by adding up the numbers on the top and bottom - they should be the same on both sides
$12 \to 12 + 0$
$6 \to 7 - 1$
Impact of this question
580 views around the world | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 11, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8088239431381226, "perplexity": 564.6448033315487}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-40/segments/1600400187354.1/warc/CC-MAIN-20200918061627-20200918091627-00207.warc.gz"} |
http://manual.gromacs.org/documentation/2020.4/install-guide/index.html | Installation guide¶
Introduction to building GROMACS¶
These instructions pertain to building GROMACS 2020.4. You might also want to check the up-to-date installation instructions.
Quick and dirty installation¶
1. Get the latest version of your C and C++ compilers.
2. Check that you have CMake version 3.9.6 or later.
3. Get and unpack the latest version of the GROMACS tarball.
4. Make a separate build directory and change to it.
5. Run cmake with the path to the source as an argument
6. Run make, make check, and make install
7. Source GMXRC to get access to GROMACS
Or, as a sequence of commands to execute:
tar xfz gromacs-2020.4.tar.gz
cd gromacs-2020.4
mkdir build
cd build
cmake .. -DGMX_BUILD_OWN_FFTW=ON -DREGRESSIONTEST_DOWNLOAD=ON
make
make check
sudo make install
source /usr/local/gromacs/bin/GMXRC
This will download and build first the prerequisite FFT library followed by GROMACS. If you already have FFTW installed, you can remove that argument to cmake. Overall, this build of GROMACS will be correct and reasonably fast on the machine upon which cmake ran. On another machine, it may not run, or may not run fast. If you want to get the maximum value for your hardware with GROMACS, you will have to read further. Sadly, the interactions of hardware, libraries, and compilers are only going to continue to get more complex.
Quick and dirty cluster installation¶
On a cluster where users are expected to be running across multiple nodes using MPI, make one installation similar to the above, and another using -DGMX_MPI=on and which is building only mdrun, because that is the only component of GROMACS that uses MPI. The latter will install a single simulation engine binary, i.e. mdrun_mpi when the default suffix is used. Hence it is safe and common practice to install this into the same location where the non-MPI build is installed.
Typical installation¶
As above, and with further details below, but you should consider using the following CMake options with the appropriate value instead of xxx :
• -DCMAKE_C_COMPILER=xxx equal to the name of the C99 Compiler you wish to use (or the environment variable CC)
• -DCMAKE_CXX_COMPILER=xxx equal to the name of the C++98 compiler you wish to use (or the environment variable CXX)
• -DGMX_MPI=on to build using MPI support (generally good to combine with building only mdrun)
• -DGMX_GPU=on to build using nvcc to run using NVIDIA CUDA GPU acceleration or an OpenCL GPU
• -DGMX_USE_OPENCL=on to build with OpenCL support enabled. GMX_GPU must also be set.
• -DGMX_SIMD=xxx to specify the level of SIMD support of the node on which GROMACS will run
• -DGMX_BUILD_MDRUN_ONLY=on for building only mdrun, e.g. for compute cluster back-end nodes
• -DGMX_DOUBLE=on to build GROMACS in double precision (slower, and not normally useful)
• -DCMAKE_PREFIX_PATH=xxx to add a non-standard location for CMake to search for libraries, headers or programs
• -DCMAKE_INSTALL_PREFIX=xxx to install GROMACS to a non-standard location (default /usr/local/gromacs)
• -DBUILD_SHARED_LIBS=off to turn off the building of shared libraries to help with static linking
• -DGMX_FFT_LIBRARY=xxx to select whether to use fftw3, mkl or fftpack libraries for FFT support
• -DCMAKE_BUILD_TYPE=Debug to build GROMACS in debug mode
Building older versions¶
Installation instructions for old GROMACS versions can be found at the GROMACS documentation page.
Prerequisites¶
Platform¶
GROMACS can be compiled for many operating systems and architectures. These include any distribution of Linux, Mac OS X or Windows, and architectures including x86, AMD64/x86-64, several PowerPC including POWER8, ARM v7, ARM v8, and SPARC VIII.
Compiler¶
GROMACS can be compiled on any platform with ANSI C99 and C++14 compilers, and their respective standard C/C++ libraries. Good performance on an OS and architecture requires choosing a good compiler. We recommend gcc, because it is free, widely available and frequently provides the best performance.
You should strive to use the most recent version of your compiler. Since we require full C++14 support the minimum supported compiler versions are
• GNU (gcc) 5.1
• Intel (icc) 17.0.1
• LLVM (clang) 3.6
• Microsoft (MSVC) 2017
Other compilers may work (Cray, Pathscale, older clang) but do not offer competitive performance. We recommend against PGI because the performance with C++ is very bad.
The xlc compiler is not supported and version 16.1 does not compile on POWER architectures for GROMACS-2020.4. We recommend to use the gcc compiler instead, as it is being extensively tested.
You may also need the most recent version of other compiler toolchain components beside the compiler itself (e.g. assembler or linker); these are often shipped by your OS distribution’s binutils package.
C++14 support requires adequate support in both the compiler and the C++ library. The gcc and MSVC compilers include their own standard libraries and require no further configuration. If your vendor’s compiler also manages the standard library library via compiler flags, these will be honored. For configuration of other compilers, read on.
On Linux, both the Intel and clang compiler use the libstdc++ which comes with gcc as the default C++ library. For GROMACS, we require the compiler to support libstc++ version 5.1 or higher. To select a particular libstdc++ library, provide the path to g++ with -DGMX_GPLUSPLUS_PATH=/path/to/g++.
On Windows with the Intel compiler, the MSVC standard library is used, and at least MSVC 2017 is required. Load the enviroment variables with vcvarsall.bat.
To build with clang and llvm’s libcxx standard library, use -DCMAKE_CXX_FLAGS=-stdlib=libc++.
If you are running on Mac OS X, the best option is the Intel compiler. Both clang and gcc will work, but they produce lower performance and each have some shortcomings. clang 3.8 now offers support for OpenMP, and so may provide decent performance.
For all non-x86 platforms, your best option is typically to use gcc or the vendor’s default or recommended compiler, and check for specialized information below.
For updated versions of gcc to add to your Linux OS, see
Compiling with parallelization options¶
For maximum performance you will need to examine how you will use GROMACS and what hardware you plan to run on. Often OpenMP parallelism is an advantage for GROMACS, but support for this is generally built into your compiler and detected automatically.
GPU support¶
GROMACS has excellent support for NVIDIA GPUs supported via CUDA. On Linux, NVIDIA CUDA toolkit with minimum version 9.0 is required, and the latest version is strongly encouraged. NVIDIA GPUs with at least NVIDIA compute capability 3.0 are required. You are strongly recommended to get the latest CUDA version and driver that supports your hardware, but beware of possible performance regressions in newer CUDA versions on older hardware. While some CUDA compilers (nvcc) might not officially support recent versions of gcc as the back-end compiler, we still recommend that you at least use a gcc version recent enough to get the best SIMD support for your CPU, since GROMACS always runs some code on the CPU. It is most reliable to use the same C++ compiler version for GROMACS code as used as the host compiler for nvcc.
To make it possible to use other accelerators, GROMACS also includes OpenCL support. The minimum OpenCL version required is 1.2 and only 64-bit implementations are supported. The current OpenCL implementation is recommended for use with GCN-based AMD GPUs, and on Linux we recommend the ROCm runtime. Intel integrated GPUs are supported with the Neo drivers. OpenCL is also supported with NVIDIA GPUs, but using the latest NVIDIA driver (which includes the NVIDIA OpenCL runtime) is recommended. Also note that there are performance limitations (inherent to the NVIDIA OpenCL runtime). It is not possible to configure both CUDA and OpenCL support in the same build of GROMACS, nor to support both Intel and other vendors’ GPUs with OpenCL. A 64-bit implementation of OpenCL is required and therefore OpenCL is only supported on 64-bit platforms.
MPI support¶
GROMACS can run in parallel on multiple cores of a single workstation using its built-in thread-MPI. No user action is required in order to enable this.
If you wish to run in parallel on multiple machines across a network, you will need to have
• an MPI library installed that supports the MPI 1.3 standard, and
• wrapper compilers that will compile code using that library.
To compile with MPI set your compiler to the normal (non-MPI) compiler and add -DGMX_MPI=on to the cmake options. It is possible to set the compiler to the MPI compiler wrapper but it is neither necessary nor recommended.
The GROMACS team recommends OpenMPI version 1.6 (or higher), MPICH version 1.4.1 (or higher), or your hardware vendor’s MPI installation. The most recent version of either of these is likely to be the best. More specialized networks might depend on accelerations only available in the vendor’s library. LAM-MPI might work, but since it has been deprecated for years, it is not supported.
For example, depending on your actual MPI library, use cmake -DCMAKE_C_COMPILER=mpicc -DCMAKE_CXX_COMPILER=mpicxx -DGMX_MPI=on.
CMake¶
GROMACS builds with the CMake build system, requiring at least version 3.9.6. You can check whether CMake is installed, and what version it is, with cmake --version. If you need to install CMake, then first check whether your platform’s package management system provides a suitable version, or visit the CMake installation page for pre-compiled binaries, source code and installation instructions. The GROMACS team recommends you install the most recent version of CMake you can.
Fast Fourier Transform library¶
Many simulations in GROMACS make extensive use of fast Fourier transforms, and a software library to perform these is always required. We recommend FFTW (version 3 or higher only) or Intel MKL. The choice of library can be set with cmake -DGMX_FFT_LIBRARY=<name>, where <name> is one of fftw3, mkl, or fftpack. FFTPACK is bundled with GROMACS as a fallback, and is acceptable if simulation performance is not a priority. When choosing MKL, GROMACS will also use MKL for BLAS and LAPACK (see linear algebra libraries). Generally, there is no advantage in using MKL with GROMACS, and FFTW is often faster. With PME GPU offload support using CUDA, a GPU-based FFT library is required. The CUDA-based GPU FFT library cuFFT is part of the CUDA toolkit (required for all CUDA builds) and therefore no additional software component is needed when building with CUDA GPU acceleration.
Using FFTW¶
FFTW is likely to be available for your platform via its package management system, but there can be compatibility and significant performance issues associated with these packages. In particular, GROMACS simulations are normally run in “mixed” floating-point precision, which is suited for the use of single precision in FFTW. The default FFTW package is normally in double precision, and good compiler options to use for FFTW when linked to GROMACS may not have been used. Accordingly, the GROMACS team recommends either
• that you permit the GROMACS installation to download and build FFTW from source automatically for you (use cmake -DGMX_BUILD_OWN_FFTW=ON), or
• that you build FFTW from the source code.
If you build FFTW from source yourself, get the most recent version and follow the FFTW installation guide. Choose the precision for FFTW (i.e. single/float vs. double) to match whether you will later use mixed or double precision for GROMACS. There is no need to compile FFTW with threading or MPI support, but it does no harm. On x86 hardware, compile with both --enable-sse2 and --enable-avx for FFTW-3.3.4 and earlier. From FFTW-3.3.5, you should also add --enable-avx2 also. On Intel processors supporting 512-wide AVX, including KNL, add --enable-avx512 also. FFTW will create a fat library with codelets for all different instruction sets, and pick the fastest supported one at runtime. On ARM architectures with NEON SIMD support and IBM Power8 and later, you definitely want version 3.3.5 or later, and to compile it with --enable-neon and --enable-vsx, respectively, for SIMD support. If you are using a Cray, there is a special modified (commercial) version of FFTs using the FFTW interface which can be slightly faster.
Using MKL¶
Use MKL bundled with Intel compilers by setting up the compiler environment, e.g., through source /path/to/compilervars.sh intel64 or similar before running CMake including setting -DGMX_FFT_LIBRARY=mkl.
If you need to customize this further, use
cmake -DGMX_FFT_LIBRARY=mkl \
-DMKL_LIBRARIES="/full/path/to/libone.so;/full/path/to/libtwo.so" \
-DMKL_INCLUDE_DIR="/full/path/to/mkl/include"
The full list and order(!) of libraries you require are found in Intel’s MKL documentation for your system.
Using ARM Performance Libraries¶
The ARM Performance Libraries provides FFT transforms implementation for ARM architectures. Preliminary support is provided for ARMPL in GROMACS through its FFTW-compatible API. Assuming that the ARM HPC toolchain environment including the ARMPL paths are set up (e.g. through loading the appropriate modules like module load Module-Prefix/arm-hpc-compiler-X.Y/armpl/X.Y) use the following cmake options:
cmake -DGMX_FFT_LIBRARY=fftw3 \
-DFFTWF_LIBRARY="${ARMPL_DIR}/lib/libarmpl_lp64.so" \ -DFFTWF_INCLUDE_DIR=${ARMPL_DIR}/include
Other optional build components¶
• Run-time detection of hardware capabilities can be improved by linking with hwloc, which is automatically enabled if detected.
• Hardware-optimized BLAS and LAPACK libraries are useful for a few of the GROMACS utilities focused on normal modes and matrix manipulation, but they do not provide any benefits for normal simulations. Configuring these is discussed at linear algebra libraries.
• The built-in GROMACS trajectory viewer gmx view requires X11 and Motif/Lesstif libraries and header files. You may prefer to use third-party software for visualization, such as VMD or PyMol.
• An external TNG library for trajectory-file handling can be used by setting -DGMX_EXTERNAL_TNG=yes, but TNG 1.7.10 is bundled in the GROMACS source already.
• The lmfit library for Levenberg-Marquardt curve fitting is used in GROMACS. Only lmfit 7.0 is supported. A reduced version of that library is bundled in the GROMACS distribution, and the default build uses it. That default may be explicitly enabled with -DGMX_USE_LMFIT=internal. To use an external lmfit library, set -DGMX_USE_LMFIT=external, and adjust CMAKE_PREFIX_PATH as needed. lmfit support can be disabled with -DGMX_USE_LMFIT=none.
• zlib is used by TNG for compressing some kinds of trajectory data
• Building the GROMACS documentation is optional, and requires ImageMagick, pdflatex, bibtex, doxygen, python 3.5, sphinx 1.6.1, and pygments.
• The GROMACS utility programs often write data files in formats suitable for the Grace plotting tool, but it is straightforward to use these files in other plotting programs, too.
• Set -DGMX_PYTHON_PACKAGE=ON when configuring GROMACS with CMake to enable additional CMake targets for the gmxapi Python package and sample_restraint package from the main GROMACS CMake build. This supports additional testing and documentation generation.
Doing a build of GROMACS¶
This section will cover a general build of GROMACS with CMake, but it is not an exhaustive discussion of how to use CMake. There are many resources available on the web, which we suggest you search for when you encounter problems not covered here. The material below applies specifically to builds on Unix-like systems, including Linux, and Mac OS X. For other platforms, see the specialist instructions below.
Configuring with CMake¶
CMake will run many tests on your system and do its best to work out how to build GROMACS for you. If your build machine is the same as your target machine, then you can be sure that the defaults and detection will be pretty good. However, if you want to control aspects of the build, or you are compiling on a cluster head node for back-end nodes with a different architecture, there are a few things you should consider specifying.
The best way to use CMake to configure GROMACS is to do an “out-of-source” build, by making another directory from which you will run CMake. This can be outside the source directory, or a subdirectory of it. It also means you can never corrupt your source code by trying to build it! So, the only required argument on the CMake command line is the name of the directory containing the CMakeLists.txt file of the code you want to build. For example, download the source tarball and use
tar xfz gromacs-2020.4.tgz
cd gromacs-2020.4
mkdir build-gromacs
cd build-gromacs
cmake ..
You will see cmake report a sequence of results of tests and detections done by the GROMACS build system. These are written to the cmake cache, kept in CMakeCache.txt. You can edit this file by hand, but this is not recommended because you could make a mistake. You should not attempt to move or copy this file to do another build, because file paths are hard-coded within it. If you mess things up, just delete this file and start again with cmake.
If there is a serious problem detected at this stage, then you will see a fatal error and some suggestions for how to overcome it. If you are not sure how to deal with that, please start by searching on the web (most computer problems already have known solutions!) and then consult the gmx-users mailing list. There are also informational warnings that you might like to take on board or not. Piping the output of cmake through less or tee can be useful, too.
Once cmake returns, you can see all the settings that were chosen and information about them by using e.g. the curses interface
ccmake ..
You can actually use ccmake (available on most Unix platforms) directly in the first step, but then most of the status messages will merely blink in the lower part of the terminal rather than be written to standard output. Most platforms including Linux, Windows, and Mac OS X even have native graphical user interfaces for cmake, and it can create project files for almost any build environment you want (including Visual Studio or Xcode). Check out running CMake for general advice on what you are seeing and how to navigate and change things. The settings you might normally want to change are already presented. You may make changes, then re-configure (using c), so that it gets a chance to make changes that depend on yours and perform more checking. It may take several configuration passes to reach the desired configuration, in particular if you need to resolve errors.
When you have reached the desired configuration with ccmake, the build system can be generated by pressing g. This requires that the previous configuration pass did not reveal any additional settings (if it did, you need to configure once more with c). With cmake, the build system is generated after each pass that does not produce errors.
You cannot attempt to change compilers after the initial run of cmake. If you need to change, clean up, and start again.
Where to install GROMACS¶
GROMACS is installed in the directory to which CMAKE_INSTALL_PREFIX points. It may not be the source directory or the build directory. You require write permissions to this directory. Thus, without super-user privileges, CMAKE_INSTALL_PREFIX will have to be within your home directory. Even if you do have super-user privileges, you should use them only for the installation phase, and never for configuring, building, or running GROMACS!
Using CMake command-line options¶
Once you become comfortable with setting and changing options, you may know in advance how you will configure GROMACS. If so, you can speed things up by invoking cmake and passing the various options at once on the command line. This can be done by setting cache variable at the cmake invocation using -DOPTION=VALUE. Note that some environment variables are also taken into account, in particular variables like CC and CXX.
For example, the following command line
cmake .. -DGMX_GPU=ON -DGMX_MPI=ON -DCMAKE_INSTALL_PREFIX=/home/marydoe/programs
can be used to build with CUDA GPUs, MPI and install in a custom location. You can even save that in a shell script to make it even easier next time. You can also do this kind of thing with ccmake, but you should avoid this, because the options set with -D will not be able to be changed interactively in that run of ccmake.
SIMD support¶
GROMACS has extensive support for detecting and using the SIMD capabilities of many modern HPC CPU architectures. If you are building GROMACS on the same hardware you will run it on, then you don’t need to read more about this, unless you are getting configuration warnings you do not understand. By default, the GROMACS build system will detect the SIMD instruction set supported by the CPU architecture (on which the configuring is done), and thus pick the best available SIMD parallelization supported by GROMACS. The build system will also check that the compiler and linker used also support the selected SIMD instruction set and issue a fatal error if they do not.
Valid values are listed below, and the applicable value with the largest number in the list is generally the one you should choose. In most cases, choosing an inappropriate higher number will lead to compiling a binary that will not run. However, on a number of processor architectures choosing the highest supported value can lead to performance loss, e.g. on Intel Skylake-X/SP and AMD Zen.
1. None For use only on an architecture either lacking SIMD, or to which GROMACS has not yet been ported and none of the options below are applicable.
2. SSE2 This SIMD instruction set was introduced in Intel processors in 2001, and AMD in 2003. Essentially all x86 machines in existence have this, so it might be a good choice if you need to support dinosaur x86 computers too.
3. SSE4.1 Present in all Intel core processors since 2007, but notably not in AMD Magny-Cours. Still, almost all recent processors support this, so this can also be considered a good baseline if you are content with slow simulations and prefer portability between reasonably modern processors.
4. AVX_128_FMA AMD Bulldozer, Piledriver (and later Family 15h) processors have this.
5. AVX_256 Intel processors since Sandy Bridge (2011). While this code will work on the AMD Bulldozer and Piledriver processors, it is significantly less efficient than the AVX_128_FMA choice above - do not be fooled to assume that 256 is better than 128 in this case.
6. AVX2_128 AMD Zen/Zen2 and Hygon Dhyana microarchitecture processors; it will enable AVX2 with 3-way fused multiply-add instructions. While these microarchitectures do support 256-bit AVX2 instructions, hence AVX2_256 is also supported, 128-bit will generally be faster, in particular when the non-bonded tasks run on the CPU – hence the default AVX2_128. With GPU offload however AVX2_256 can be faster on Zen processors.
7. AVX2_256 Present on Intel Haswell (and later) processors (2013), and it will also enable Intel 3-way fused multiply-add instructions.
8. AVX_512 Skylake-X desktop and Skylake-SP Xeon processors (2017); it will generally be fastest on the higher-end desktop and server processors with two 512-bit fused multiply-add units (e.g. Core i9 and Xeon Gold). However, certain desktop and server models (e.g. Xeon Bronze and Silver) come with only one AVX512 FMA unit and therefore on these processors AVX2_256 is faster (compile- and runtime checks try to inform about such cases). Additionally, with GPU accelerated runs AVX2_256 can also be faster on high-end Skylake CPUs with both 512-bit FMA units enabled.
9. AVX_512_KNL Knights Landing Xeon Phi processors
10. Sparc64_HPC_ACE Fujitsu machines like the K computer have this.
11. IBM_VMX Power6 and similar Altivec processors have this.
12. IBM_VSX Power7, Power8, Power9 and later have this.
13. ARM_NEON 32-bit ARMv7 with NEON support.
14. ARM_NEON_ASIMD 64-bit ARMv8 and later.
The CMake configure system will check that the compiler you have chosen can target the architecture you have chosen. mdrun will check further at runtime, so if in doubt, choose the lowest number you think might work, and see what mdrun says. The configure system also works around many known issues in many versions of common HPC compilers.
A further GMX_SIMD=Reference option exists, which is a special SIMD-like implementation written in plain C that developers can use when developing support in GROMACS for new SIMD architectures. It is not designed for use in production simulations, but if you are using an architecture with SIMD support to which GROMACS has not yet been ported, you may wish to try this option instead of the default GMX_SIMD=None, as it can often out-perform this when the auto-vectorization in your compiler does a good job. And post on the GROMACS mailing lists, because GROMACS can probably be ported for new SIMD architectures in a few days.
CMake advanced options¶
The options that are displayed in the default view of ccmake are ones that we think a reasonable number of users might want to consider changing. There are a lot more options available, which you can see by toggling the advanced mode in ccmake on and off with t. Even there, most of the variables that you might want to change have a CMAKE_ or GMX_ prefix. There are also some options that will be visible or not according to whether their preconditions are satisfied.
Helping CMake find the right libraries, headers, or programs¶
If libraries are installed in non-default locations their location can be specified using the following variables:
• CMAKE_INCLUDE_PATH for header files
• CMAKE_LIBRARY_PATH for libraries
• CMAKE_PREFIX_PATH for header, libraries and binaries (e.g. /usr/local).
The respective include, lib, or bin is appended to the path. For each of these variables, a list of paths can be specified (on Unix, separated with “:”). These can be set as enviroment variables like:
CMAKE_PREFIX_PATH=/opt/fftw:/opt/cuda cmake ..
(assuming bash shell). Alternatively, these variables are also cmake options, so they can be set like -DCMAKE_PREFIX_PATH=/opt/fftw:/opt/cuda.
The CC and CXX environment variables are also useful for indicating to cmake which compilers to use. Similarly, CFLAGS/CXXFLAGS can be used to pass compiler options, but note that these will be appended to those set by GROMACS for your build platform and build type. You can customize some of this with advanced CMake options such as CMAKE_C_FLAGS and its relatives.
See also the page on CMake environment variables.
CUDA GPU acceleration¶
If you have the CUDA Toolkit installed, you can use cmake with:
cmake .. -DGMX_GPU=ON -DCUDA_TOOLKIT_ROOT_DIR=/usr/local/cuda
(or whichever path has your installation). In some cases, you might need to specify manually which of your C++ compilers should be used, e.g. with the advanced option CUDA_HOST_COMPILER.
By default, code will be generated for the most common CUDA architectures. However, to reduce build time and binary size we do not generate code for every single possible architecture, which in rare cases (say, Tegra systems) can result in the default build not being able to use some GPUs. If this happens, or if you want to remove some architectures to reduce binary size and build time, you can alter the target CUDA architectures. This can be done either with the GMX_CUDA_TARGET_SM or GMX_CUDA_TARGET_COMPUTE CMake variables, which take a semicolon delimited string with the two digit suffixes of CUDA (virtual) architectures names, for instance “35;50;51;52;53;60”. For details, see the “Options for steering GPU code generation” section of the nvcc man / help or Chapter 6. of the nvcc manual.
The GPU acceleration has been tested on AMD64/x86-64 platforms with Linux, Mac OS X and Windows operating systems, but Linux is the best-tested and supported of these. Linux running on POWER 8, ARM v7 and v8 CPUs also works well.
Experimental support is available for compiling CUDA code, both for host and device, using clang (version 6.0 or later). A CUDA toolkit is still required but it is used only for GPU device code generation and to link against the CUDA runtime library. The clang CUDA support simplifies compilation and provides benefits for development (e.g. allows the use code sanitizers in CUDA host-code). Additionally, using clang for both CPU and GPU compilation can be beneficial to avoid compatibility issues between the GNU toolchain and the CUDA toolkit. clang for CUDA can be triggered using the GMX_CLANG_CUDA=ON CMake option. Target architectures can be selected with GMX_CUDA_TARGET_SM, virtual architecture code is always embedded for all requested architectures (hence GMX_CUDA_TARGET_COMPUTE is ignored). Note that this is mainly a developer-oriented feature and it is not recommended for production use as the performance can be significantly lower than that of code compiled with nvcc (and it has also received less testing). However, note that since clang 5.0 the performance gap is only moderate (at the time of writing, about 20% slower GPU kernels), so this version could be considered in non performance-critical use-cases.
OpenCL GPU acceleration¶
The primary targets of the GROMACS OpenCL support is accelerating simulations on AMD and Intel hardware. For AMD, we target both discrete GPUs and APUs (integrated CPU+GPU chips), and for Intel we target the integrated GPUs found on modern workstation and mobile hardware. The GROMACS OpenCL on NVIDIA GPUs works, but performance and other limitations make it less practical (for details see the user guide).
To build GROMACS with OpenCL support enabled, two components are required: the OpenCL headers and the wrapper library that acts as a client driver loader (so-called ICD loader). The additional, runtime-only dependency is the vendor-specific GPU driver for the device targeted. This also contains the OpenCL compiler. As the GPU compute kernels are compiled on-demand at run time, this vendor-specific compiler and driver is not needed for building GROMACS. The former, compile-time dependencies are standard components, hence stock versions can be obtained from most Linux distribution repositories (e.g. opencl-headers and ocl-icd-libopencl1 on Debian/Ubuntu). Only the compatibility with the required OpenCL version 1.2 needs to be ensured. Alternatively, the headers and library can also be obtained from vendor SDKs (e.g. from AMD), which must be installed in a path found in CMAKE_PREFIX_PATH (or via the environment variables AMDAPPSDKROOT or CUDA_PATH).
To trigger an OpenCL build the following CMake flags must be set
cmake .. -DGMX_GPU=ON -DGMX_USE_OPENCL=ON
To build with support for Intel integrated GPUs, it is required to add -DGMX_OPENCL_NB_CLUSTER_SIZE=4 to the cmake command line, so that the GPU kernels match the characteristics of the hardware. The Neo driver is recommended.
On Mac OS, an AMD GPU can be used only with OS version 10.10.4 and higher; earlier OS versions are known to run incorrectly.
By default, any clFFT library on the system will be used with GROMACS, but if none is found then the code will fall back on a version bundled with GROMACS. To require GROMACS to link with an external library, use
cmake .. -DGMX_GPU=ON -DGMX_USE_OPENCL=ON -DclFFT_ROOT_DIR=/path/to/your/clFFT -DGMX_EXTERNAL_CLFFT=TRUE
Static linking¶
Dynamic linking of the GROMACS executables will lead to a smaller disk footprint when installed, and so is the default on platforms where we believe it has been tested repeatedly and found to work. In general, this includes Linux, Windows, Mac OS X and BSD systems. Static binaries take more space, but on some hardware and/or under some conditions they are necessary, most commonly when you are running a parallel simulation using MPI libraries (e.g. Cray).
• To link GROMACS binaries statically against the internal GROMACS libraries, set -DBUILD_SHARED_LIBS=OFF.
• To link statically against external (non-system) libraries as well, set -DGMX_PREFER_STATIC_LIBS=ON. Note, that in general cmake picks up whatever is available, so this option only instructs cmake to prefer static libraries when both static and shared are available. If no static version of an external library is available, even when the aforementioned option is ON, the shared library will be used. Also note that the resulting binaries will still be dynamically linked against system libraries on platforms where that is the default. To use static system libraries, additional compiler/linker flags are necessary, e.g. -static-libgcc -static-libstdc++.
• To attempt to link a fully static binary set -DGMX_BUILD_SHARED_EXE=OFF. This will prevent CMake from explicitly setting any dynamic linking flags. This option also sets -DBUILD_SHARED_LIBS=OFF and -DGMX_PREFER_STATIC_LIBS=ON by default, but the above caveats apply. For compilers which don’t default to static linking, the required flags have to be specified. On Linux, this is usually CFLAGS=-static CXXFLAGS=-static.
gmxapi C++ API¶
For dynamic linking builds and on non-Windows platforms, an extra library and headers are installed by setting -DGMXAPI=ON (default). Build targets gmxapi-cppdocs and gmxapi-cppdocs-dev produce documentation in docs/api-user and docs/api-dev, respectively. For more project information and use cases, refer to the tracked Issue 2585, associated GitHub gmxapi projects, or DOI 10.1093/bioinformatics/bty484.
gmxapi is not yet tested on Windows or with static linking, but these use cases are targeted for future versions.
Portability aspects¶
A GROMACS build will normally not be portable, not even across hardware with the same base instruction set, like x86. Non-portable hardware-specific optimizations are selected at configure-time, such as the SIMD instruction set used in the compute kernels. This selection will be done by the build system based on the capabilities of the build host machine or otherwise specified to cmake during configuration.
Often it is possible to ensure portability by choosing the least common denominator of SIMD support, e.g. SSE2 for x86, and ensuring the you use cmake -DGMX_USE_RDTSCP=off if any of the target CPU architectures does not support the RDTSCP instruction. However, we discourage attempts to use a single GROMACS installation when the execution environment is heterogeneous, such as a mix of AVX and earlier hardware, because this will lead to programs (especially mdrun) that run slowly on the new hardware. Building two full installations and locally managing how to call the correct one (e.g. using a module system) is the recommended approach. Alternatively, as at the moment the GROMACS tools do not make strong use of SIMD acceleration, it can be convenient to create an installation with tools portable across different x86 machines, but with separate mdrun binaries for each architecture. To achieve this, one can first build a full installation with the least-common-denominator SIMD instruction set, e.g. -DGMX_SIMD=SSE2, then build separate mdrun binaries for each architecture present in the heterogeneous environment. By using custom binary and library suffixes for the mdrun-only builds, these can be installed to the same location as the “generic” tools installation. Building just the mdrun binary is possible by setting the -DGMX_BUILD_MDRUN_ONLY=ON option.
Linear algebra libraries¶
As mentioned above, sometimes vendor BLAS and LAPACK libraries can provide performance enhancements for GROMACS when doing normal-mode analysis or covariance analysis. For simplicity, the text below will refer only to BLAS, but the same options are available for LAPACK. By default, CMake will search for BLAS, use it if it is found, and otherwise fall back on a version of BLAS internal to GROMACS. The cmake option -DGMX_EXTERNAL_BLAS=on will be set accordingly. The internal versions are fine for normal use. If you need to specify a non-standard path to search, use -DCMAKE_PREFIX_PATH=/path/to/search. If you need to specify a library with a non-standard name (e.g. ESSL on Power machines or ARMPL on ARM machines), then set -DGMX_BLAS_USER=/path/to/reach/lib/libwhatever.a.
If you are using Intel MKL for FFT, then the BLAS and LAPACK it provides are used automatically. This could be over-ridden with GMX_BLAS_USER, etc.
On Apple platforms where the Accelerate Framework is available, these will be automatically used for BLAS and LAPACK. This could be over-ridden with GMX_BLAS_USER, etc.
Building with MiMiC QM/MM support¶
MiMiC QM/MM interface integration will require linking against MiMiC communication library, that establishes the communication channel between GROMACS and CPMD. The MiMiC Communication library can be downloaded here. Compile and install it. Check that the installation folder of the MiMiC library is added to CMAKE_PREFIX_PATH if it is installed in non-standard location. Building QM/MM-capable version requires double-precision version of GROMACS compiled with MPI support:
• -DGMX_DOUBLE=ON -DGMX_MPI -DGMX_MIMIC=ON
Changing the names of GROMACS binaries and libraries¶
It is sometimes convenient to have different versions of the same GROMACS programs installed. The most common use cases have been single and double precision, and with and without MPI. This mechanism can also be used to install side-by-side multiple versions of mdrun optimized for different CPU architectures, as mentioned previously.
By default, GROMACS will suffix programs and libraries for such builds with _d for double precision and/or _mpi for MPI (and nothing otherwise). This can be controlled manually with GMX_DEFAULT_SUFFIX (ON/OFF), GMX_BINARY_SUFFIX (takes a string) and GMX_LIBS_SUFFIX (also takes a string). For instance, to set a custom suffix for programs and libraries, one might specify:
cmake .. -DGMX_DEFAULT_SUFFIX=OFF -DGMX_BINARY_SUFFIX=_mod -DGMX_LIBS_SUFFIX=_mod
Thus the names of all programs and libraries will be appended with _mod.
Changing installation tree structure¶
By default, a few different directories under CMAKE_INSTALL_PREFIX are used when when GROMACS is installed. Some of these can be changed, which is mainly useful for packaging GROMACS for various distributions. The directories are listed below, with additional notes about some of them. Unless otherwise noted, the directories can be renamed by editing the installation paths in the main CMakeLists.txt.
bin/
The standard location for executables and some scripts. Some of the scripts hardcode the absolute installation prefix, which needs to be changed if the scripts are relocated. The name of the directory can be changed using CMAKE_INSTALL_BINDIR CMake variable.
include/gromacs/
The standard location for installed headers.
lib/
The standard location for libraries. The default depends on the system, and is determined by CMake. The name of the directory can be changed using CMAKE_INSTALL_LIBDIR CMake variable.
lib/pkgconfig/
Information about the installed libgromacs library for pkg-config is installed here. The lib/ part adapts to the installation location of the libraries. The installed files contain the installation prefix as absolute paths.
share/cmake/
CMake package configuration files are installed here.
share/gromacs/
Various data files and some documentation go here. The first part can be changed using CMAKE_INSTALL_DATADIR, and the second by using GMX_INSTALL_DATASUBDIR Using these CMake variables is the preferred way of changing the installation path for share/gromacs/top/, since the path to this directory is built into libgromacs as well as some scripts, both as a relative and as an absolute path (the latter as a fallback if everything else fails).
share/man/
Installed man pages go here.
Compiling and linking¶
Once you have configured with cmake, you can build GROMACS with make. It is expected that this will always complete successfully, and give few or no warnings. The CMake-time tests GROMACS makes on the settings you choose are pretty extensive, but there are probably a few cases we have not thought of yet. Search the web first for solutions to problems, but if you need help, ask on gmx-users, being sure to provide as much information as possible about what you did, the system you are building on, and what went wrong. This may mean scrolling back a long way through the output of make to find the first error message!
If you have a multi-core or multi-CPU machine with N processors, then using
make -j N
will generally speed things up by quite a bit. Other build generator systems supported by cmake (e.g. ninja) also work well.
Building only mdrun¶
This is now supported with the cmake option -DGMX_BUILD_MDRUN_ONLY=ON, which will build a different version of libgromacs and the mdrun program. Naturally, now make install installs only those products. By default, mdrun-only builds will default to static linking against GROMACS libraries, because this is generally a good idea for the targets for which an mdrun-only build is desirable.
Installing GROMACS¶
Finally, make install will install GROMACS in the directory given in CMAKE_INSTALL_PREFIX. If this is a system directory, then you will need permission to write there, and you should use super-user privileges only for make install and not the whole procedure.
Getting access to GROMACS after installation¶
GROMACS installs the script GMXRC in the bin subdirectory of the installation directory (e.g. /usr/local/gromacs/bin/GMXRC), which you should source from your shell:
source /your/installation/prefix/here/bin/GMXRC
It will detect what kind of shell you are running and set up your environment for using GROMACS. You may wish to arrange for your login scripts to do this automatically; please search the web for instructions on how to do this for your shell.
Many of the GROMACS programs rely on data installed in the share/gromacs subdirectory of the installation directory. By default, the programs will use the environment variables set in the GMXRC script, and if this is not available they will try to guess the path based on their own location. This usually works well unless you change the names of directories inside the install tree. If you still need to do that, you might want to recompile with the new install location properly set, or edit the GMXRC script.
GROMACS also installs a CMake toolchains file to help with building client software. For an installation at /your/installation/prefix/here, toolchain files will be installed at /your/installation/prefix/here/share/cmake/gromacs${GMX_LIBS_SUFFIX}/gromacs-toolchain${GMX_LIBS_SUFFIX}.cmake where ${GMX_LIBS_SUFFIX} is as documented above. Testing GROMACS for correctness¶ Since 2011, the GROMACS development uses an automated system where every new code change is subject to regression testing on a number of platforms and software combinations. While this improves reliability quite a lot, not everything is tested, and since we increasingly rely on cutting edge compiler features there is non-negligible risk that the default compiler on your system could have bugs. We have tried our best to test and refuse to use known bad versions in cmake, but we strongly recommend that you run through the tests yourself. It only takes a few minutes, after which you can trust your build. The simplest way to run the checks is to build GROMACS with -DREGRESSIONTEST_DOWNLOAD, and run make check. GROMACS will automatically download and run the tests for you. Alternatively, you can download and unpack the GROMACS regression test suite http://gerrit.gromacs.org/download/regressiontests-2020.4.tar.gz tarball yourself and use the advanced cmake option REGRESSIONTEST_PATH to specify the path to the unpacked tarball, which will then be used for testing. If the above does not work, then please read on. The regression tests are also available from the download section. Once you have downloaded them, unpack the tarball, source GMXRC as described above, and run ./gmxtest.pl all inside the regression tests folder. You can find more options (e.g. adding double when using double precision, or -only expanded to run just the tests whose names match “expanded”) if you just execute the script without options. Hopefully, you will get a report that all tests have passed. If there are individual failed tests it could be a sign of a compiler bug, or that a tolerance is just a tiny bit too tight. Check the output files the script directs you too, and try a different or newer compiler if the errors appear to be real. If you cannot get it to pass the regression tests, you might try dropping a line to the gmx-users mailing list, but then you should include a detailed description of your hardware, and the output of gmx mdrun -version (which contains valuable diagnostic information in the header). A build with -DGMX_BUILD_MDRUN_ONLY cannot be tested with make check from the build tree, because most of the tests require a full build to run things like grompp. To test such an mdrun fully requires installing it to the same location as a normal build of GROMACS, downloading the regression tests tarball manually as described above, sourcing the correct GMXRC and running the perl script manually. For example, from your GROMACS source directory: mkdir build-normal cd build-normal cmake .. -DCMAKE_INSTALL_PREFIX=/your/installation/prefix/here make -j 4 make install cd .. mkdir build-mdrun-only cd build-mdrun-only cmake .. -DGMX_MPI=ON -DGMX_GPU=ON -DGMX_BUILD_MDRUN_ONLY=ON -DCMAKE_INSTALL_PREFIX=/your/installation/prefix/here make -j 4 make install cd /to/your/unpacked/regressiontests source /your/installation/prefix/here/bin/GMXRC ./gmxtest.pl all -np 2 If your mdrun program has been suffixed in a non-standard way, then the ./gmxtest.pl -mdrun option will let you specify that name to the test machinery. You can use ./gmxtest.pl -double to test the double-precision version. You can use ./gmxtest.pl -crosscompiling to stop the test harness attempting to check that the programs can be run. You can use ./gmxtest.pl -mpirun srun if your command to run an MPI program is called srun. The make check target also runs integration-style tests that may run with MPI if GMX_MPI=ON was set. To make these work with various possible MPI libraries, you may need to set the CMake variables MPIEXEC, MPIEXEC_NUMPROC_FLAG, MPIEXEC_PREFLAGS and MPIEXEC_POSTFLAGS so that mdrun-mpi-test_mpi would run on multiple ranks via the shell command ${MPIEXEC} ${MPIEXEC_NUMPROC_FLAG}${NUMPROC} ${MPIEXEC_PREFLAGS} \ mdrun-mpi-test_mpi${MPIEXEC_POSTFLAGS} -otherflags
A typical example for SLURM is
cmake .. -DGMX_MPI=on -DMPIEXEC=srun -DMPIEXEC_NUMPROC_FLAG=-n -DMPIEXEC_PREFLAGS= -DMPIEXEC_POSTFLAGS=
Testing GROMACS for performance¶
We are still working on a set of benchmark systems for testing the performance of GROMACS. Until that is ready, we recommend that you try a few different parallelization options, and experiment with tools such as gmx tune_pme.
Validating GROMACS for source code modifications¶
When building GROMACS from a release tarball, the build process automatically checks if any file contributing to the build process have been modified since they have been packed in the archive. This results in the marking of the version as either MODIFIED (if the source files have been modified) or UNCHECKED (if no validation was possible, e.g. if no Python installation was found). The actual checking is performed by comparing a checksum stored in the release tarball against one generated by the createFileHash.py Python script during the build configuration. When running a GROMACS binary, the checksum is also printed in the log file, together with a message if there is a mismatch or no validation has been possible.
This allows users to check whether the binary they are using was built from source code that is identical to the source code released by the GROMACS team. Thus unintentional modifications to the source code for building binaries that are used for running production simulations are easily detectable. Additionally, by manually setting a version tag using the GMX_VERSION_STRING_OF_FORK cmake option, users can mark a modified GROMACS release code with their custom version string suffix.
Having difficulty?¶
You are not alone - this can be a complex task! If you encounter a problem with installing GROMACS, then there are a number of locations where you can find assistance. It is recommended that you follow these steps to find the solution:
1. Read the installation instructions again, taking note that you have followed each and every step correctly.
2. Search the GROMACS webpage and users emailing list for information on the error. Adding site:https://mailman-1.sys.kth.se/pipermail/gromacs.org_gmx-users to a Google search may help filter better results.
3. Search the internet using a search engine such as Google.
4. Post to the GROMACS users emailing list gmx-users for assistance. Be sure to give a full description of what you have done and why you think it did not work. Give details about the system on which you are installing. Copy and paste your command line and as much of the output as you think might be relevant - certainly from the first indication of a problem. In particular, please try to include at least the header from the mdrun logfile, and preferably the entire file. People who might volunteer to help you do not have time to ask you interactive detailed follow-up questions, so you will get an answer faster if you provide as much information as you think could possibly help. High quality bug reports tend to receive rapid high quality answers.
Special instructions for some platforms¶
Building on Windows¶
Building on Windows using native compilers is rather similar to building on Unix, so please start by reading the above. Then, download and unpack the GROMACS source archive. Make a folder in which to do the out-of-source build of GROMACS. For example, make it within the folder unpacked from the source archive, and call it build-gromacs.
For CMake, you can either use the graphical user interface provided on Windows, or you can use a command line shell with instructions similar to the UNIX ones above. If you open a shell from within your IDE (e.g. Microsoft Visual Studio), it will configure the environment for you, but you might need to tweak this in order to get either a 32-bit or 64-bit build environment. The latter provides the fastest executable. If you use a normal Windows command shell, then you will need to either set up the environment to find your compilers and libraries yourself, or run the vcvarsall.bat batch script provided by MSVC (just like sourcing a bash script under Unix).
With the graphical user interface, you will be asked about what compilers to use at the initial configuration stage, and if you use the command line they can be set in a similar way as under UNIX.
Unfortunately -DGMX_BUILD_OWN_FFTW=ON (see Using FFTW) does not work on Windows, because there is no supported way to build FFTW on Windows. You can either build FFTW some other way (e.g. MinGW), or use the built-in fftpack (which may be slow), or using MKL.
For the build, you can either load the generated solutions file into e.g. Visual Studio, or use the command line with cmake --build so the right tools get used.
Building on Cray¶
GROMACS builds mostly out of the box on modern Cray machines, but you may need to specify the use of static binaries with -DGMX_BUILD_SHARED_EXE=off, and you may need to set the F77 environmental variable to ftn when compiling FFTW. The ARM ThunderX2 Cray XC50 machines differ only in that the recommended compiler is the ARM HPC Compiler (armclang).
Building on Solaris¶
The built-in GROMACS processor detection does not work on Solaris, so it is strongly recommended that you build GROMACS with -DGMX_HWLOC=on and ensure that the CMAKE_PREFIX_PATH includes the path where the hwloc headers and libraries can be found. At least version 1.11.8 of hwloc is recommended.
Oracle Developer Studio is not a currently supported compiler (and does not currently compile GROMACS correctly, perhaps because the thread-MPI atomics are incorrectly implemented in GROMACS).
Fujitsu PRIMEHPC¶
This is the architecture of the K computer, which uses Fujitsu Sparc64VIIIfx chips. On this platform, GROMACS has accelerated group kernels using the HPC-ACE instructions, no accelerated Verlet kernels, and a custom build toolchain. Since this particular chip only does double precision SIMD, the default setup is to build GROMACS in double. Since most users only need single, we have added an option GMX_RELAXED_DOUBLE_PRECISION to accept single precision square root accuracy in the group kernels; unless you know that you really need 15 digits of accuracy in each individual force, we strongly recommend you use this. Note that all summation and other operations are still done in double.
The recommended configuration is to use
cmake .. -DCMAKE_TOOLCHAIN_FILE=Toolchain-Fujitsu-Sparc64-mpi.cmake \
-DCMAKE_PREFIX_PATH=/your/fftw/installation/prefix \
-DCMAKE_INSTALL_PREFIX=/where/gromacs/should/be/installed \
-DGMX_MPI=ON \
-DGMX_BUILD_MDRUN_ONLY=ON \
-DGMX_RELAXED_DOUBLE_PRECISION=ON
make
make install
Intel Xeon Phi¶
Xeon Phi processors, hosted or self-hosted, are supported. Only symmetric (aka native) mode is supported on Knights Corner. The performance depends among other factors on the system size, and for now the performance might not be faster than CPUs. When building for it, the recommended configuration is
cmake .. -DCMAKE_TOOLCHAIN_FILE=Platform/XeonPhi
make
make install
The Knights Landing-based Xeon Phi processors behave like standard x86 nodes, but support a special SIMD instruction set. When cross-compiling for such nodes, use the AVX_512_KNL SIMD flavor. Knights Landing processors support so-called “clustering modes” which allow reconfiguring the memory subsystem for lower latency. GROMACS can benefit from the quadrant or SNC clustering modes. Care needs to be taken to correctly pin threads. In particular, threads of an MPI rank should not cross cluster and NUMA boundaries. In addition to the main DRAM memory, Knights Landing has a high-bandwidth stacked memory called MCDRAM. Using it offers performance benefits if it is ensured that mdrun runs entirely from this memory; to do so it is recommended that MCDRAM is configured in “Flat mode” and mdrun is bound to the appropriate NUMA node (use e.g. numactl --membind 1 with quadrant clustering mode).
Tested platforms¶
While it is our best belief that GROMACS will build and run pretty much everywhere, it is important that we tell you where we really know it works because we have tested it. We do test on Linux, Windows, and Mac with a range of compilers and libraries for a range of our configuration options. Every commit in our git source code repository is currently tested on x86 with a number of gcc versions ranging from 5.1 through 9.1, version 19 of the Intel compiler, and Clang versions 3.6 through 8. For this, we use a variety of GNU/Linux flavors and versions as well as Windows (where we test only MSVC 2017). Other compiler, library, and OS versions are tested less frequently. For details, you can have a look at the continuous integration server used by GROMACS, which runs Jenkins.
We test irregularly on ARM v7, ARM v8, Cray, Fujitsu PRIMEHPC, Power8, Power9, Google Native Client and other environments, and with other compilers and compiler versions, too. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.30682042241096497, "perplexity": 3662.446593396059}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-50/segments/1606141213431.41/warc/CC-MAIN-20201130100208-20201130130208-00716.warc.gz"} |
https://link.springer.com/article/10.1186%2Fs12879-019-4263-1 | BMC Infectious Diseases
, 19:628
Detection of risk clusters for deaths due to tuberculosis specifically in areas of southern Brazil where the disease was supposedly a non-problem
• Luana Seles Alves
• Danielle Talita dos Santos
• Marcos Augusto Moraes Arcoverde
• Thais Zamboni Berra
• Luiz Henrique Arroyo
• Antônio Carlos Vieira Ramos
• Ivaneliza Simionato de Assis
• Ana Angélica Rêgo de Queiroz
• Jonas Boldini Alonso
• Josilene Dália Alves
• Marcela Paschoal Popolin
• Mellina Yamamura
• Juliane de Almeida Crispim
• Elma Mathias Dessunti
• Pedro Fredemir Palha
• Francisco Chiaraval-Neto
• Carla Nunes
• Ricardo Alexandre Arcêncio
Open Access
Research article
Part of the following topical collections:
1. Tuberculosis and other mycobacterial diseases
Abstract
Background
Tuberculosis (TB) is the infectious disease that kills the most people worldwide. The use of geoepidemiological techniques to demonstrate the dynamics of the disease in vulnerable communities is essential for its control. Thus, this study aimed to identify risk clusters for TB deaths and their variation over time.
Methods
This ecological study considered cases of TB deaths in residents of Londrina, Brazil between 2008 and 2015. We used standard, isotonic scan statistics for the detection of spatial risk clusters. The Poisson discrete model was adopted with the high and low rates option used for 10, 30 and 50% of the population at risk, with circular format windows and 999 replications considered the maximum cluster size. Getis-Ord Gi* (Gi*) statistics were used to diagnose hotspot areas for TB mortality. Kernel density was used to identify whether the clusters changed over time.
Results
For the standard version, spatial risk clusters for 10, 30 and 50% of the exposed population were 4.9 (95% CI 2.6–9.4), 3.2 (95% CI: 2.1–5.7) and 3.2 (95% CI: 2.1–5.7), respectively. For the isotonic spatial statistics, the risk clusters for 10, 30 and 50% of the exposed population were 2.8 (95% CI: 1.5–5.1), 2.7 (95% CI: 1.6–4.4), 2.2 (95% CI: 1.4–3.9), respectively. All risk clusters were located in the eastern and northern regions of the municipality. Additionally, through Gi*, hotspot areas were identified in the eastern and western regions.
Conclusions
There were important risk areas for tuberculosis mortality in the eastern and northern regions of the municipality. Risk clusters for tuberculosis deaths were observed in areas where TB mortality was supposedly a non-problem. The isotonic and Gi* statistics were more sensitive for the detection of clusters in areas with a low number of cases; however, their applicability in public health is still restricted.
Keywords
Tuberculosis Death Spatial analysis Isotonic regression Scan statistics Cluster detection
Abbreviations
DD
Declaration of Death
FHS
Family Health Strategy
Gi*
Getis-Ord Gi* statistics
ICD
International Classification of Diseases
MHDI
Municipal Human Development Index
MIS
Mortality Information System
PHUs
Primary Health Units
TB
Tuberculosis
WHO
World Health Organization
Background
Tuberculosis (TB) is an ancient disease that remains a serious public health problem worldwide, affecting 30 countries that account for 87% of TB cases. The disease is among the infectious disease that kills the most people worldwide, more than HIV and malaria [1]. The World Health Organization (WHO) launched the ‘End TB’ strategy in 2014, aiming to achieve the elimination of TB by 2050 (< 1 case per 100,000 people), and to also reduce TB mortality by 95% by 2035; both goals are a large challenge in developing countries, such as Brazil [2].
In 2017, Brazil had an incidence rate of 44 cases per 100,000 inhabitants and a mortality rate of 2.4 per 100,000 inhabitants, with a treatment success rate of 72% among the patients monitored in 2016; this result falls short of the WHO recommendations [1]. Recently, the ‘Brazil free of tuberculosis’ strategy was adopted, which aims to improve access to diagnosis and quality treatment in order to achieve the goals defined by the WHO [2]. The strategy is also based on three pillars: integrated and patient-centred prevention and care; bold policies and supportive systems; and the intensification of research and innovation [3].
Currently, government predictions outline that Brazil will achieve the goal of reducing mortality by 2035 at the national level [2]; however, it is unlikely that this will happen at the subnational levels, i.e. states or municipalities. This is due to Brazil being one of the largest countries in the Americas, occupying almost 20.8% of the hemisphere and 47.3% of South America, making it difficult to reduce the mortality rate homogeneously throughout all regions [2].
Studying the subunits of the country and thus an approximation of local health systems is relevant in order to highlight the trends and impact of tuberculosis mortality in these scenarios [4]. Mortality due to TB is defined as a socially determined event, marked mainly by social inequalities related to income, schooling, housing conditions, labour conditions, the weakness of health services (delay in diagnosis, poor diagnosis and treatment) and the absence of social politics and social protection. The risk of deaths is influenced by these factors, which range between areas in a same city, county or country [5, 6], therefore measuring the spatial risk to which given communities are exposed can contribute to the guidance of public policies and strategic actions [7].
This situation is not static. On the contrary, it is very dynamic and varies between the regions according to the availability of resources in terms of health, social investment, urbanisation, immigration, and modes of social organisation; therefore, the risk of disease and its impact (fatality) are influenced by these social dynamics [5]. The literature indicates that, in certain territories, deaths from TB are more prevalent in areas with social problems and a lack of assistance, however, there are few studies that show this, which is important for addressing the problem [6]. Therefore, measuring the spatial risk to which given communities are exposed can contribute to the guidance of public policies and the adoption of directed and focused health measures.
Tuberculosis is a low frequency event compared to diseases such as hypertension, diabetes and malaria, among others; it affects very specific and/or minor populations or groups. Therefore, because traditional techniques, such as scan statistics, require a greater number of event occurrences, their use may lead to erroneous inferences of the non-existence of the death risk of TB in a vulnerable community when it is in fact present and imminent.
The literature has a wide variety of definitions and methodological approaches for identifying clusters [8]; various methods are compared, contrasted and matched, aiming to overcome the issue of unknown and underdiagnosed clusters and to ensure the validity, sensitivity and accuracy of the studies [9].
Through a literature review of TB mortality risk clusters, only three articles were identified in Brazil [6, 8, 9], however all of these articles applied standard scan statistics. Isotonic spatial scan statistics and Getis-Ord Gi* statistics (Gi*) can be used complementarily to increase the chances of identifying a cluster, mainly in areas where the event is more rare. Although these statistics are interesting resources to identify spatial risk clusters in the case of rare phenomena, their application in the area of geoepidemiology is still very limited. Thus, this study aimed to identify risk clusters for TB deaths, specifically in areas where TB supposedly does not seem to be a problem.
Methods
Study design and setting
This ecological study [10] was carried out in the municipality of Londrina, which is a centre for business, technology, research and health development [11]. It is situated at the following geographical coordinates: 23°18′ S latitude and 51°09′ W longitude [12]. Figure 1 illustrates the location of the municipality.
The municipal population is 548,249 inhabitants, of whom 493,520 are concentrated in the urban area, which is the second most populous city of Paraná. The municipal population density is 330.95 inhabitants/km2 [12].
In terms of social indicators, the municipality has a Municipal Human Development Index (MHDI) of 0.78, classified as a high HDI (0.700 to 0.799) according to the United Nations Development Program (UNDP) [13]. Longevity is the attribute that contributes most to the MHDI, with an index of 0.837, followed by income, with an index of 0.789, and education, with an index of 0.712. Regarding social inequality, the municipality presents a Gini coefficient of 0.42, suggesting that there is an inequality of income distribution, and a poverty rate of 36.49% [13].
The municipality has 56 primary health units (PHUs), with 86 family health strategy (FHS) teams distributed in 54 PHUs. FHS coverage is 58.62%, with 32 hospitals and two emergency care units (ECUs) [11, 12].
In 2015, Londrina had a TB incidence rate of 32.95/100,000 inhabitants, a bacillary TB incidence rate of 17.16/100,000 inhabitants and a mortality rate of 0.7/100,000 inhabitants [14].
Study observation units
The analysis units of the study were census tracts [15]. The municipality of Londrina has 713 census tracts; the 678 tracts that are considered to be urban were used in this study.
Study population and period
The study population consisted of cases of deaths caused by TB, with the Declaration of Death (DD) showing codes A15.0 to A19.9, according to the International Classification of Diseases (ICD version 10). This corresponded to all clinical forms of TB, and was assessed over the period from 2008 to 2015.
Source of information and data collection
Data were obtained from two different sources. The first source was 2010 Demographic Census of the Brazilian Institute of Geography and Statistics to obtain the maps data, and the second source was the mortality information system (MIS) of the Health Surveillance Department of the Municipal Health Department of Londrina, BR. The use of the MIS is justified because it was one of the pioneering systems to be founded in Brazil [16].
Data analysis
In the first step, descriptive statistics were performed, including the calculation of absolute frequency and proportion measures for the categorical variables and location (mean and median) and dispersion (standard deviation) measures for the continuous variables, using Statistica (v12.0) software.
Subsequently, the geographic coordinates of each address were searched using the free access Google Earth technology and the geo-referencing technique of the cases was performed using the Terraview (v4.2.2) software. The SaTScan v9.4.2 software was used to identify the risk areas for TB mortality, initially applied to the standard, and then the isotonic version [17, 18].
Scan statistics is a technique developed by Kulldorff and Nagarwalla [13]. It consists of circles that move throughout the study area around the centroids, which correspond to the centre of each territorial unit under analysis [19]. The formation of the spatial clusters is based on the calculation of the number of events found within each circle. If the observed value of the region delimited by the circle is larger than expected, it is called a risk cluster; if the value is lower than expected, it is called a low-risk or protective cluster. This procedure is repeated until all centroids are tested [20].
In the centralisation process, the log likelihood ratio (LLR) of each potential cluster is formulated based on the calculation of the mortality that is observed and expectedin and out of the circular window in which the p-value is assigned, according to the following formula [21]:
$$\mathrm{LLR}=\log {\left(\frac{{\mathrm{O}}_{\mathrm{in}}}{{\mathrm{E}}_{\mathrm{in}}}\right)}^{\mathrm{O}\mathrm{in}}{\left(\frac{\mathrm{O}-{\mathrm{O}}_{\mathrm{in}}}{\mathrm{O}-{\mathrm{E}}_{\mathrm{in}}}\right)}^{\mathrm{O}-{\mathrm{O}}_{\mathrm{in}}}$$
in which O represents the observed cases and E represents the expected cases. In this way, Oin and Ein denote the number of observed and expected cases in the window, respectively. Ein is calculated by multiplying the deaths due to TB by the population of the census tracts. The higher the LLR, the less likely the cluster detection occurred due to chance [22].
After the formation of the cluster, the software also presents the spatial relative risk (SRR) value [23], which is obtained through an equation [24] that corresponds to the estimated risk within a cluster divided by the estimated risk outside the cluster. The SRR is calculated by taking into account the observed cases divided by the expected cases within the cluster, all divided by the observed cases divided by the expected cases outside the cluster. The equation is:
$$SRR=\frac{N_z/{E}_z}{\left(N-{N}_z\right)/\left({E}_{A-}{E}_Z\right)}$$
where N is the total number of cases, NZ is the number of cases in the Z cluster, EA is the expected number of cases in the region under the null hypothesis, and EZ is the expected number of cases in the Z area under the null hypothesis.
The difference between the standard and isotonic methods lies in the number of circular windows generated during the centralisation procedure; the isotonic version, instead of developing only one circular window, uses a set of different sized, overlapping circles, centred on the same centroid. It also starts from the alternative hypothesis that the mortality rate is highest within the innermost circle, a little lower between the first and second circles, and so on, until the final circle [18, 24].
In the isotonic version of a given centroid, the risk is modelled as higher within some unknown distance (d) of the centroid compared to a greater distance from the same centroid. This means that the risk is modelled as a function r(d) of the distance from the centroid, and that it uses the steps in a risk function with a single discontinuity in d [25, 26].
The risk function can be classified as a non-increasing function, i.e. the greater the distance from the centroid of the territorial unit of analysis, the smaller the spatial risk for the occurrence of death due to TB. After the identification of the purely spatial risk clusters, to assess the reliability of the SRR values, the respective 95% confidence intervals (95% CI) were calculated [27].
In terms of the spatial clusters, the Poisson method was adopted, with the high and low rates option used for the two analyses, and 10, 30 and 50% of the population at risk, with circular format windows and 999 replications considered as the maximum cluster size [28, 29].
In the third step, the Gi* statistical technique was used to analyse the spatial association of TB mortality. For this, it was necessary to calculate the TB mortality rate standardised by sex and age (TxMTBi), with age classified as less than or equal to the median, or greater than the median (56 years), according to the formula:
$$\mathrm{TxMTBi}=\frac{\Sigma\ \mathrm{of}\ \mathrm{the}\ \mathrm{standard}\mathrm{ised}\ \mathrm{by}\ \mathrm{age}\ \mathrm{X}\ \mathrm{100,000}}{\Sigma\ \mathrm{of}\ \mathrm{the}\ \mathrm{standard}\ \mathrm{population}}\ \mathrm{X}\ \frac{1}{8}$$
Next, to estimate the radius of the distance used in the Gi*, the Incremental Spatial Autocorrelation (ISA) tool provided by ArcGIS (10.5) was used. The ISA was tested for 30 distances, in which the result of the most pronounced distance was 3143.28 m with p < 0.01 [30, 31]. Also, for the spatial association analysis, the weight matrix normalised by distance was created using Geoda version 1.8 software.
The Getis-Ord General G, G(d), analysis was performed in ArcGIS (v.10.5) software. The G(d) consists of a global index to evaluate the spatial association of an attribute based on statistical distances and calculated from a sum of values for a given distance, according to the following formula [32]:
$$G(d)=\frac{\sum_{i=1}^n{\sum}_{j=1}^n{w}_{ij}(d){x}_i{x}_j}{\sum_{i=1}^n{\sum}_{j=1}^n{x}_i{x}_j},j\ not\ equal\ to\ i$$
where n corresponds to the number of areas, Wij is the value in the proximity matrix for region i with region j as a function of distance (d), and xi and xj are the values of the attributes considered in the areas i and j.
The value of G(d) is provided by a Z score, ranging from + 3 to − 3, which determines whether the attributes with high or low values are spatially grouped, with higher Z scores indicating more extreme grouping in the region, called hotspots, lower Z-scores indicating low value groupings, called coldspots, and values of 0 indicating no grouping [33, 34]. In this sense, with the intention of examining the spatial patterns in detail, the Gi* local association indicator was used. In the Gi*, the values for each location, that is, each census sector, are considered from a neighbourhood matrix.
The pseudo-significance test was used to certify the statistical validity of the results [35]. A type I error of 5% was fixed as statistically significant (p < 0.05) for all the tests.
Kernel density
An estimation of the density of the nucleus was performed every year to identify whether the conglomerates were changing over time. This analysis consisted of an exploratory interpolation in which the density was generated for the visual identification of hotspot areas, which belong to regions with a higher density of TB deaths [36]. A radius of 3143.28 m was considered, according to the analysis performed through ArcGIS (v.10.5) software. Thematic maps were also constructed using this software.
Ethical approval and consent to participate
The maps data from 2010 Demographic Census of the Brazilian Institute of Geography and Statistics are open data, and the data from the MIS were authorized of the Health Surveillance Department of the Municipal Health Department of Londrina,BR. This study was approved by the Research Ethics Committee of the School of Nursing of the University of São Paulo, Ribeirão Preto Campus, in accordance with the Guidelines and Regulatory Standards for Research with Human Subjects, Resolution No. 196/96 of the National Health Council, under Certificate of Presentation for Ethical Appreciation No. 56305516.0.0000.5393, issued on 11 December 2015. A signed consent form was not necessary as secondary data were used and the participants were not identified.
Results
A total of 61 deaths due to TB were identified, the characteristics of which are described in Table 1. According to this table, the mean age was 56.9 years with a standard deviation (SD) of 17.8; 49 (80.3%) were male, 39 (63.9%) were white, 17 (27.9%) were married and 20 (32.8%) had a high school education. According to Table 1, 32 (52.4%) presented the pulmonary clinical form of TB. All identified cases were georeferenced, with a general municipal mortality rate of 1.5 cases per 100,000 inhabitants.
Table 1
Characteristics of the individuals who died of tuberculosis in Londrina, Brazil (2008–2015)
Variable
n
%
Age (years)
< 19
1
1.6
20–39
8
13.1
40–59
27
44.3
≥ 60
25
41.0
Median
56
Mean
56.9
Gender
Male
49
80.3
Female
12
19.7
Skin colour/ethnicity
White (Caucasian)
39
63.9
Black (African)
9
14.8
Yellow (Asian)
4
6.6
Brown (Mixed race)
9
14.8
Marital status
Single
17
27.9
Married
23
37.7
Widowed
6
9.8
Divorced
6
9.8
2
3.3
No response
7
11.5
Level of education
No schooling
1
1.6
Elementary education
12
19.7
High school education
20
32.8
Higher education
15
24.6
No response
13
21.3
Occupation
Retired/pensioner
13
21.3
Homemaker
7
11.5
Miscellaneous
28
45.9
No response
13
21.3
Place of death
Hospital
54
88.5
Home
7
11.5
Yes
32
52.5
No
2
3.3
No response
27
44.3
Diagnosis confirmed by further examination
Yes
14
23.0
No
2
3.3
No response
45
73.8
Diagnosis confirmed by surgery
Yes
1
1.6
No
15
24.6
No response
45
73.8
Diagnosis confirmed by necropsy
Yes
5
8.2
No
36
59.0
No response
20
32.8
Death certified by
Assistant
17
27.9
Substitute
19
31.1
Death Surveillance Service
2
3.3
TB site
Pulmonary
32
52.4
Extra-pulmonary
29
47.5
Source: MIS Londrina, BR 2016
Regarding the application of the standard for high rates, a risk cluster was identified for each percentage of the population exposed, i.e. 10, 30 and 50%, with the SRR and 95% CI values expressed in Fig. 2.
In Fig. 2, the clusters of risk covered the north and east regions of the municipality, with 12 deaths in the cluster with 10% of the population at risk and 29 deaths for 30 and 50%. Also, usingk the traditional scan, for low rates and 10% of the population exposed, a protection cluster was identified in the northwestern region of the municipality, where there were no deaths due to TB, whereas for 30 and 50% of the population at risk, the protection cluster involved the entire southern region of the municipality, with 5 deaths for each cluster.
Referring to the isotonic version, as seen in Fig. 3, spatial risk clusters were also found in the northern and eastern regions of the municipality, demonstrating that there was no change in the location of the risk clusters. The protection clusters also maintained the same location as in the traditional scan. The SRR and 95% CI values are described in Fig. 3.
In the isotonic version, the steps in the risk function are present, which corresponds to the multiple circular windows formed during the centralisation process of the scan. This also maximises the LLR. These steps allowed for the verification of the intensity of mortality within the clusters. Thus, for the risk cluster with 10% of the population, step 1 had the lowest radius (0.3 km; Table 2) and the highest SRR value (20.8; 95% CI 7.5–57.1), totalling 4 deaths, whereas step 2 had a radius of 1.8 km and a SRR of 2.05 (95% CI 1.1–3.0), totalling 14 deaths.
Table 2
Risk clusters for TB deaths, according to the steps in risk function, in Londrina, Brazil (2008–2015)
Rate
Pop. at risk (%)
Steps in risk function
No. census sectors
Pop. of cluster
Annual cases/100,000
No. Cases
Expected cases
SRRa (95% CI)
High
10
1
2
1846
27.0
4
0.2
20.8 (7.5–57.1)
0.3
2
62
47193
3.7
14
5.7
2.05 (1.1–3.7)
1.8
30
1
2
1846
27.0
4
0.2
24.4 (8.9–67.3)
0.3
2
71
55843
3.5
16
6.8
2.43 (1.4–4.3)
1.9
3
107
79956
3.2
21
2.9
2.31 (1.3–3.9)
2.5
4
130
95969
3.1
24
3.6
2.09 (1.2–3.4)
2.8
5
149
112273
3.0
27
2.0
2.03 (1.2–3.3)
2.9
50
1
2
1846
27.0
4
0.2
24.46 (8.9–67.3)
0.3
2
71
55843
3.5
16
6.8
2.43 (1.4–4.3)
1.9
3
107
79956
3.2
21
2.9
2.31 (1.3–3.9)
2.5
4
130
95969
3.1
24
1.9
2.09 (1.2–3.4)
2.8
5
149
112273
3.0
27
2.0
2.03 (1.2–3.3)
2.9
6
281
203846
2.3
38
11.7
1.4 (1.3–3.9)
3.9
Low
10
1
63
53032
0
0
6.1
0 (0.0)
1.6
30
1
31
23448
0
0
2.7
0 (0.0)
4.0
2
216
35782
1.7
5
15.5
0.25 (0.1–0.6)
6.0
50
1
31
23448
0
0
2.7
0 (0.0)
4.0
2
217
144348
0.4
5
15.6
0.23 (0.09–0.6)
6.0
3
230
154346
0.5
6
1.3
0.6 (0.1–0.5)
6.0
4
261
156194
0.6
8
2.3
0.63 (0.1–0.6)
6.3
aSpatial relative risk
The risk cluster for 50% of the population at risk had six steps, with step 1 having a radius of 0.3 km and SRR of 24.4 (95% CI 8.9–67.3), with 4 deaths, and step 6 having a radius of 3.9 km and SRR of 1.4 (95% CI 1.3–3.9), with 38 deaths. In this way, the smaller the cluster radius of the risk clusters, the higher the SRR value.
Regarding the protection clusters, step 1 had the lowest SRR, as it occurred in the cluster for 30% of the population at risk, in which step 1 presented a radius of 4.0 km and SRR of 0 and step 2 had a radius of 6.0 km and SRR of 0.25 (95% CI 0.1–0.6), totalling 5 deaths, i.e. the smaller the radius, the smaller the SRR value.
Table 2 shows the spatial characteristics of TB deaths within the clusters identified through the isotonic version according to the steps in risk function.
Table 3 compares 346 the data obtained through the standard scan and the isotonic scan.
Table 3
Comparative analysis of standard and isotonic scans of TB mortality, Londrina, Brazil (2008–2015)
Rate
High
Low
Pop. at risk (%)
10
30
50
10
30
50
No. census sectors
Standard
32
153
153
63
216
217
Isotonic
60
149
281
63
216
261
Pop. of cluster
Standard
22993
102433
102433
53032
143762
144328
Isotonic
47193
112265
203830
53032
143762
172652
Annual cases/100,000
Standard
6.4
3.4
3.4
0
0.4
0.4
Isotonic
3.7
3.0
2.3
0
0.4
0.6
No. cases
Standard
12
29
29
0
5
5
Isotonic
14
27
38
0
5
8
Expected cases
Standard
2.9
13.3
13.3
6
18.3
18.4
Isotonic
5.9
14
25.8
6.1
18.3
22
Standard
1.4
2.4
2.4
1.6
5.9
6.0
Isotonic
1.8
2.9
3.9
1.6
5.9
6.3
LLRa
Standard
8.7
9.7
9.7
6.4
8.7
8.7
Isotonic
9.6
12.3
12.7
6.4
9.5
9.9
p-value
Standard
0.05
0.02**
0.03**
0.05
0.04**
0.04**
Isotonic
0.04**
0.01**
< 0.01**
0.05
0.02**
0.02**
aLog likelihood ratio; **p < 0.05
Table 3 shows that the isotonic version covered more census tracts due to the larger radius dimensions. For 10 and 50% of the population, there were 60 and 281 sectors in the isotonic versus 32 and 153 sectors in the traditional version, respectively.
In terms of TB cases, the traditional version captured fewer cases than the isotonic version, with the traditional version presenting 29 deaths for 50% of the population, compared to 38 deaths in the isotonic version. The SRR in the traditional version remained larger than that in the isotonic version, ranging from 3.2 to 4.9 and 2.2 to 2.8, respectively; however, in the isotonic version, the SRR assumed higher standards within the steps, ranging from 1.4 to 24.4.
A similar case occurred for the mortality rates, with the traditional version calculating 3.4 to 6.4 deaths per 100,000 inhabitants, whereas the isotonic version calculated 2.3 to 3.7 deaths per 100,000 inhabitants. However, the rates within the steps ranged from 3.0 to 27.0 deaths per 100,000 inhabitants.
For the protection clusters, the data were similar when considering 10 and 30% of the population at risk, however, when the size of the cluster was changed to 50% of the population, the isotonic version grouped more census sectors, with 261 sectors and more TB deaths, totalling 8. An important aspect to be emphasised is the LLR values; as Table 3 shows, in the isotonic version, the LLRs were increased for both the risk and protection clusters, highlighting that the randomness of the clusters in the isotonic version was lower than in the traditional version.
Regarding the spatial association, Fig. 4 shows the hotspots and coldspots detected by the global and local analysis of the Getis-Ord statistic. The general index of the Getis-Ord statistic (Fig. 4b) had a value of 0.002, demonstrating a positive spatial relationship. The local analysis Gi* (Fig. 4a) demonstrated the formation of hotspots in the eastern regions, with 95% confidence, and in the western region, with 99% confidence, where the Gi Z-score was higher than 1.96. Coldspots were also found in the northwestern and southern regions of the municipality, with 95% confidence level. The pseudo-significance test (Fig. 4b) confirmed both the statistical significance of the analysis, with p < 0.01, and the non-randomness of the clusters.
Figure 5 shows the distribution of the highest density of deaths due to TB for each year of this study.
Discussion
This study aimed to identify risk clusters for TB deaths, specifically in areas where TB supposedly does not seem to be a problem. We observed that the isotonic version covered a greater area of risk than the traditional method, areas that would be considered to be non-problematic or unknown by health care services.
The difference between the traditional method and the isotonic version consists of the number of circular windows generated during the centralisation procedure. The isotonic version, instead of developing only one circular window, uses a set of different sized, overlapping circles, centred on the same centroid. It also starts from the alternative hypothesis that the mortality rate is highest within the innermost circle, a little lower between the first and second circles, and so on, until the final circle [18]. Despite the isotonic version evaluating a window with multiple circles, only a single circle provides the highest likelihood and therefore defines the most probable cluster; in this way, the isotonic version and Gi* proved to be more suitable spatial techniques to analyse territorial subunits and with rarer events.
When Gi* was performed, a new hotspot region was identified, which would have been unknown or underdiagnosed by scan statistics. Although this technique does not follow the same analysis pattern as scan statistics (Fig. 4), it diagnosed clusters in areas where TB was supposedly not a problem.
These findings are important to keep in mind when considering the procedures and tools that have been used by health surveillance and health care workers. When the results are negative, it is likely that these areas will not be prioritised in terms of active TB case finding, the education of health professionals and community, and investigations into health care services, among other actions [37, 38]. When risk clusters for TB deaths are identified, these areas might be prioritised in terms of new resources and investment to improve health conditions and access [6, 7]. thus advancing health equity. The results might motivate integration between epidemiological surveillance activities and Primary Health Care and this way, early diagnosis, the active search for respiratory symptomatology, and the follow-up of patients.
Due to the development of information technology, epidemiology has added a series of modern instruments to its arsenal, which allow for the consideration of the issue of space and to deepen reflections on social relations and the conditions that differ between the risk of dying and living in the different areas under investigation; this study has produced important contributions to these areas.
In relation to the profile of the deaths investigated in the study, the most affected age group corresponded to the economically active population, corroborating the findings in the literature [39, 40]. Another important finding was that, in spite of the predominance of middle-aged deaths, deaths in older adults were also highlighted as, due to the increased longevity of the population, the municipality is facing an increasing number of older adults with TB. Senility has been found to be a risk factor for TB disease [41, 42, 43]. Males were more frequently affected by death, as was the case in the studies by Dale [44], Beyene [45] and Ferrer [46], which associated this fact with the cultural, economic and social factors related to TB exposure.
Studies show that TB mortality in Brazil occurs predominantly in the non-white population [9, 47, 48]. However, in the present study, the white population was most affected. This was probably due to the fact that the municipality was colonised by Europeans and 70% of the population identifies as white [26, 49]. The majority of cases had a complete high school education, unlike the findings in the literature, which report that the level of schooling is an essential tool for understanding TB patients in terms of their clinical situation and adherence to treatment, with increased education reducing the index and risk of death [50, 51, 52].
Regarding occupation, retirees/pensioners were prevalent. According to Cavalcante [53], this is due to the fact that retirees present greater vulnerability in terms of economic conditions, difficulties in transportation to health services, abandonment by family members and the difficulties in implementing public policy that meet the health demands of older adults.
The majority of the deaths occurred in the hospital after receiving medical care, with this finding highlighting difficulties in the early diagnosis of TB and the consequent delay in the treatment of these patients; this may be due to shortcomings in the primary healthcare system. It is important to highlight that the coverage of the FHS is approximately 58% in the municipality [53, 54, 55, 56].
This study showed the pulmonary form of TB to be the most frequent in cases of death, which has also been observed in other studies [44, 50]. However, there was no bacteriological or histological confirmation information (ICD A16.2) for the classification of death.
Regarding the methods of analysis used to identify the risk of mortality in the areas under study, both techniques showed spatial risk and protection clusters for the occurrence of death due to TB (Figs. 2, 3 and 4) in the same regions of the municipality, but with different conformations. The isotonic analysis produced spatial risk clusters with larger dimensions, grouping more census tracts and calculating a greater number of deaths, compared to the standard version. This finding corroborates a study carried out by Kulldorff [18] on breast cancer in the United States.
As highlighted in the results of the study, a spatial scan detects the general location of the cluster by treating the SRR as a constant value, whereas the isotonic version presents the steps in risk function, which stratifies the radius sizes and SRR values within the cluster. This allows for a better diagnosis of the mortality in the municipality and shows areas with real risks of the event or those that constitute regions of protection.
In addition to the discussion of protection clusters, which were identified by both analyses (traditional and isotonic) and in the Gi* analysis, large differences were not observed in terms of the protection areas when the approaches were compared. Specifically regarding the protection areas shown by the study, it should be mentioned that the results were derived from data generated by health services and, therefore, their existence may be due to the underreporting of TB, although MIS is considered the gold standard throughout the country.
Through the kernel density analysis, there was little variation in the spatial distribution of deaths over time. Moreover, the areas of risk identified in the other spatial techniques remained the same, highlighting the eastern region, which continued to have a high density of deaths in all study years.
Mortality from tuberculosis can be influenced by the degree of integration between epidemiological surveillance activities and care provided over time, especially with regard to primary health care. Changes in health policies that do not focus on strengthening primary health care are commonly observed in Brazil. Therefore, mortality rates are also influenced by health actions, such as the training of health professionals to perform early diagnosis, the active search for respiratory symptomatology, and the follow-up of patients. In addition, local socioeconomic inequalities also suffer from variations in space-time, directly related with TB mortality.
This study worked with a small number of observations, since death due to TB is an infrequent phenomenon in the region. Thus, using traditional scan statistics might result in false negative areas of risk, which could compromise the surveillance actions of the city.
Since this study introduced alternative methods for diagnosing risk clusters and confirmed areas that were considered to be non-problematic, this study can become a reference for other small Brazilian municipalities (about 5,000 cities) where TB mortality may still be occult or silent. The application of the Gi* and kernel methods is more frequent than the isotonic spatial scan statistic, yet, when they are used together, the results become much more consistent, reliable and valid.
A reduction in TB mortality requires an understating of the dynamics of TB at the local level, not only at the national or state levels. Since most Brazilian municipalities are small in size, new approaches, including geo-statistics, are absolutely necessary to unravel some mysteries. Stevens and Pfeiffer [57] corroborate this idea by emphasising that innovative methodologies for a more congruous spatial approach to health enable the discovery of results that are more in line with the real situation and can provide guidance for health decision making.
The authors understand that the study might be a reference for diagnosing risk TB mortality and others rarer diseases, as well as a tool to guide policy makers, managers, stakeholders in the allocation of resources, such as cash transfers (Bolsa Família) and others social pockets according to the areas of highest risk [1, 2, 3].
The limitations of this study include the use of secondary data, which may have introduced bias due to the presence of gaps or incomplete data. It should also be noted that for the spatial analyses, only the cases of the deaths of individuals living in the urban area of the municipality were considered.
Conclusions
In conclusion, risk areas for tuberculosis mortality have been identified, including areas where TB was supposedly not a problem. These findings were achieved due to the combination of complementary methods. This study does not allow for a conclusion in terms of the best method for estimating the spatial risk for small regions, since the concepts and approach of each method are different. For this, a different study design would be necessary, with a focus on geostatistical analysis through simulations and more dense and robust tests. These findings show the need to match methods to confer more accurate results, specifically in areas where the phenomenon is rare.
Notes
Acknowledgements
We are grateful to the Municipal Secretariat for Health of Londrina, for the partnership and support that they provided in the materialisation of the study.
Authors’ contributions
LA* was responsible for performing the data collection, analysing and interpreting the data, and drafting and editing the article. DS, MA, TB and LA were responsible for data analysis, and helped to revise the article. AR, IA, AQ, and JA1 analysed the data. JA2, MP, MY, JC and ED designed the study and revised the article. PP, FC, CN and RA critically revised and polished the article, and also contributed to designing the research. RA conceived and directed the research, revising the article. All authors have read and approved the final manuscript and approve of the publication.
Funding
Alves, LS received financial assistance for partial expenses of the from the São Paulo Research Foundation (Process number: 2015/17586–3) and Coordination for the Improvement of Higher Education Personnel.
Ethics approval and consent to participate
The study was approved by the Human Research Ethics Committee of the University of São Paulo at Ribeirão Preto College of Nursing, CAAE 56305516.0.0000.5393, issued on 11 December 2015. The Committee accepted a statement with justification for the waiver of the consent term due to the fact that the research was carried out with secondary data from the MIS and the IBGE. The Brazilian legislation regarding Resolution 466/2012 was respected.
Not applicable.
Competing interests
The authors declare that they have no competing interests.
References
1. 1.
World Health Organization. Global Tuberculosis Report 2018. Geneva: WHO press, World Health Organization; 2017. http://apps.who.int/iris/bitstream/10665/259366/1/9789241565516-eng.pdf?ua=1. Accessed 12 Dec 2017Google Scholar
2. 2.
Brasil. Ministério da Saúde Secretaria de Vigilância em Saúde Departamento de Vigilância das Doenças Transmissíveis Coordenação Geral do Programa Nacional de Controle da Tuberculose 2017. http://portalarquivos.saude.gov.br/images/pdf/2017/fevereiro/24/Plano-Nacional-Tuberculose.pdf. Accessed 12 Dec 2017.
3. 3.
World Health Organization. Global Tuberculosis Report 2017. Geneva: WHO press, World Health Organization; 2017. http://apps.who.int/medicinedocs/documents/s23098en/s23098en.pdf. Accessed 12 Dec 2017Google Scholar
4. 4.
Albuquerque M d FPM d, Batista J d’A L, Ximenes RA d A, Carvalho MS, GTN D, Rodrigues LC. Risk factors associated with death in patients who initiate treatment for tuberculosis after two different follow-up periods. Rev Bras Epidemiol. 2009;12:513–22.
5. 5.
Berra TZ, Queiroz AA, Yamamura M, Arroyo LH, Garcia MC, Popolin MP, Santos DT, Ramos AC, Alves LS, Fronteira IE, Chiaravalloti NF. Spatial risk of tuberculosis mortality and social vulnerability in Northeast Brazil. Rev Soc Bras Med Trop. 2017;50(5):693–7.
6. 6.
Santos-Neto M, Yamamura M, Garcia MCC, Popolin MP, Rodrigues LBB, Chiaravalloti Neto F, et al. Pulmonary tuberculosis in São Luis, state of Maranhão, Brazil: space and space-time risk clusters for death (2008-2012). Rev Soc Bras Med Trop. 2015;48(l1):69–76.
7. 7.
Yamamura M, Santos-Neto M, Santos RA, Garcia MC, Nogueira JD, Arcêncio RA. Epidemiological characteristics of cases of death from tuberculosis and vulnerable territories. Rev Latinoam Enferm. 2015;23(5):910–8.
8. 8.
Elliot P, Wakefield JC, Best NG, Briggs DJ. Spatial epidemiology: methods and applications. Oxford: Oxford University Press; 2000.Google Scholar
9. 9.
Grubesic TH, Wei R, Murray AT. Spatial clustering overview and comparison: accuracy, sensitivity, and computational expense. Ann Assoc Am Geogr. 2014;104(6):1134–56.
10. 10.
Rothman KJ, Greenland S, Lash TL. Modern Epidemiology. 3rd ed. Philadelphia: Lippincott Williams & Wilkins; 2008.Google Scholar
11. 11.
Prefeitura do município de Londrina. Secretaria Municipal de Saúde. Plano Municipal de Saúde 2014-2017. 2015. http://www1.londrina.pr.gov.br/dados/images/stories/Storage/sec_saude/Plano%20Municial/plano_municipal_de_saude_2014_2017.pdf. Accessed 12 Dec 2017.Google Scholar
12. 12.
13. 13.
Programa das Nações Unidas para o Desenvolvimento. Atlas do Desenvolvimento Humano nas Regiões Metropolitanas Brasileiras. – Brasília: PNUD, Ipea, FJP, 2014. http://www.atlasbrasil.org.br/2013/data/rawData/publicacao_atlas_rm.pdf. Accessed 12 Dec 2017.
14. 14.
Brasil. Ministério da Saúde. Secretaria de vigilância em saúde. Panorama da tuberculose no Brasil. 2014. Accessed 12 Dec 2017.Google Scholar
15. 15.
Instituto Brasileiro de Geografia e Estatística. Censo demográfico 2010: resultados gerais da amostra. IBGE. 2012. http://www.ibge.gov.br/home/estatistica/populacao/censo2010/resultados_gerais_amostra/default_resultados_gerais_amostra.shtm. Accessed 12 Dec 2017.
16. 16.
Rocha MS, de Oliveira GP, Aguiar FP, Saraceni V, Pinheiro RS, Rocha MS, et al. Do que morrem os pacientes com tuberculose: causas múltiplas de morte de uma coorte de casos notificados e uma proposta de investigação de causas presumíveis. Cad Saúde Pública. 2015;31(4):709–21.
17. 17.
Kulldorff M, Nagarwalla N. Spatial disease clusters: detection and inference. Stat Med. 1995;14:799–810.
18. 18.
Kulldorff M. An isotonic spatial scan statistic for geographical disease surveillance. J Natl Inst Public Heal. 1999;48:94–101.Google Scholar
19. 19.
Olfatifar M, Karami M, Hosseini SM, Parvin M. Clustering of pulmonary tuberculosis in Hamadan province, western Iran: A population based cross sectional study (2005–2013). J Res Health Sci. 2016;16(3):166–9.
20. 20.
DE Lucena EFS, Moraes RM. Detecção de agrupamentos espaço-temporais para identificação de áreas de risco de homicídios por arma branca em João Pessoa, PB. Boletim de Ciências Geodésicas. 2012;18:605–23.Google Scholar
21. 21.
Waller LA, Gotway CA. Applied spatial statistics for public health data. Georgia: Wiley; 2004.
22. 22.
Gao F, Abe EM, Li S, Zhang L, He J-C, Zhang S, et al. Fine scale spatial-temporal cluster analysis for the infection risk of schistosomiasis japonica using space-time scan statistics. Parasit Vectors. 2014;7:578.
23. 23.
Jardine CG. Role of risk communication in a comprehensive risk management approach. Encycl Quant Risk Anal Assess. 2008:1584–7.Google Scholar
24. 24.
Prates MO, Kulldorff M, Assunção RM. Relative risk estimates from spatial and space–time scan statistics: are they biased? Stat Med. 2014;33(Suppl 15):2634–44.
25. 25.
Li XZ, Wang JF, Yang WZ, Li ZJ, Lai SJ. A spatial scan statistic for nonisotropic two-level risk cluster. Stat Med. 2012;31:177–87.
26. 26.
Kulldorff M, Alessandra T, Guedes C. SaTScan TM Manual do Usuário. 2016. https://www.satscan.org/cgi-bin/satscan/register.pl/SaTScan_Users_Guide.pdf?todo=process_userguide_download. Accessed 12 Dec 2017.
27. 27.
Wagner MB, Callegari-Jacques SM. Medidas de associação em estudos epidemiológicos: risco relativo e odds ratio. J Pediatr. 1998;74(Suppl 3):247–51.Google Scholar
28. 28.
Azage M, Kumie A, Worku A, Bagtzoglou AC. Childhood Diarrhea Exhibits Spatiotemporal Variation in Northwest Ethiopia: A SaTScan Spatial Statistical Analysis. Odoi A, editor. PLoS One. 2015;10:e0144690.
29. 29.
Sluydts V, Heng S, Coosemans M, Van Roey K, Gryseels C, Canier L, et al. Spatial clustering and risk factors of malaria infections in Ratanakiri Province, Cambodia Malar. J BioMed Central. 2014;13:387–99.Google Scholar
30. 30.
Stopka TJ, Goulart MA, Meyers DJ, Hutcheson M, Barton K, Onofrey S, et al. Identifying and characterizing hepatitis C virus hotspots in Massachusetts: a spatial epidemiological approach. BMC Infect. Dis. 2017;17(Suppl 1):294.
31. 31.
Zhang Y, Shen Z, Ma C, Jiang C, Feng C, Shankar N, et al. Cluster of human infections with avian influenza A (H7N9) cases: a temporal and spatial analysis. Int J Environ Res Public Health. 2015;12:816–28.
32. 32.
Getis A, Ord JK. The analysis of spatial association. Geogr Anal. 1992;24:189–206.
33. 33.
Wang T, Xue F, Chen Y, Ma Y, Liu Y. The spatial epidemiology of tuberculosis in Linyi City, China, 2005–2010. BMC Public Health. 2012;12:885.
34. 34.
Abedi-Astaneh F, Hajjaran H, Yaghoobi-Ershadi MR, Hanafi-Bojd AA, Mohebali M, Shirzadi MR, et al. Risk Mapping and Situational Analysis of Cutaneous Leishmaniasis in an Endemic Area of Central Iran: A GIS-Based Survey. Munderloh UG, editor. PLoS One. 2016;11:e0161317 Public Library of Science.
35. 35.
Câmara G, Monteiro AM, Fucks SD, Carvalho MS. Análise espacial e geoprocessamento. Análise espacial de dados geográficos; 2002.Google Scholar
36. 36.
Davies TM, Hazelton ML. Adaptive kernel estimation of spatial relative risk. Stat Med. 2010;29(23):2423–37.
37. 37.
Arcêncio RA, Arakawa T, Oliveira MF, Cardozo-Gonzales RI, Scatena LM, Ruffino-Netto A, Villa TC. Barreiras econômicas na acessibilidade ao tratamento da tuberculose em Ribeirão Preto-São Paulo. Rev Esc Enferm USP. 2011;45(5):1121-7.
38. 38.
Arcêncio RA, Oliveira MF, Cardozo-Gonzales RI, Ruffino-Netto A, Pinto IC, Villa TC. City tuberculosis control coordinators’ perspectives of patient adherence to DOT in São Paulo state, Brazil, 2005. Int J Tuberc Lung Dis. 2008;12(5):527–31 38.Google Scholar
39. 39.
Augusto CJ, Carvalho Wda S, Goncalves AD, Ceccato M d, Miranda SS, et al. Characteristics of tuberculosis in the state of Minas Gerais, Brazil: 2002–2009. J Bras Pneumol. 2013;39:357–64 Sociedade Brasileira de Pneumologia e Tisiologia.
40. 40.
Cecilio HPM, Molena-Fernandes CA, Mathias TA d F, Marcon SS. Perfil das internações e óbitos hospitalares por tuberculose. Acta Paul Enferm. 2013;26:250–5.
41. 41.
Yen Y-F, Feng J-Y, Pan S-W, Chuang P-H, Su VY-F, Su W-J. Determinants of mortality in elderly patients with tuberculosis: a population-based follow-up study. Epidemiol Infect. 2017;145:1374–81.
42. 42.
Qi Z, Yang W, Wang Y-F. Epidemiological analysis of pulmonary tuberculosis in Heilongjiang province China from 2008 to 2015. Int J Mycobacteriol. 2017;6:264.
43. 43.
Raimundo AG, Guimarães AM, Nery A, Silva SC. Tuberculose: o perfil no novo milênio. Rev Enferm UFPE line. 2015;10:1387–96.Google Scholar
44. 44.
Dale K, Tay E, Trevan P, Denholm JT. Mortality among tuberculosis cases in Victoria, 2002–2013: case fatality and factors associated with death. Int J Tuberc Lung Dis. 2016;20:515–23.
45. 45.
Beyene Y, Geresu B, Mulu A. Mortality among tuberculosis patients under DOTS programme: a historical cohort study. BMC Public Health. 2016;16:883.
46. 46.
Ferrer GCN, da Silva RM, Ferrer KT, Traebert J, Ferrer GCN, da Silva RM, et al. The burden of disease due to tuberculosis in the state of Santa Catarina. Brazil J Bras Pneumol. 2014;40:61–8.
47. 47.
Ceccon RF, Maffacciolli R, Burille A, Meneghel SN, de Oliveira DLLC, Gerhardt TE, et al. Mortalidade por tuberculose nas capitais brasileiras, 2008-2010. Epidemiol Serv Saúde. 2017;26(2):349–58.
48. 48.
Cardoso JN. Perfil epidemiológico e fatores associados ao óbito por tuberculose em Teresina; 2015.Google Scholar
49. 49.
Dessunti EM, Meier DA, Donath BC, Costa AA, Guariente MH. Infecção latente de tuberculose: adesão ao tratamento e evolução dos casos. Rev Enferm UERJ. 2013;21:711–7.Google Scholar
50. 50.
Sánchez-Barriga JJ. Tendencias de mortalidad y riesgo de muerte por tuberculosis pulmonar en las 7 regiones socioeconómicas y los 32 estados de México, 2000-2009. Arch Bronconeumol. 2015;51:16–23.
51. 51.
Blöndal K, Rahu K, Altraja A, Viiklepp P, Rahu M, Blöndal K. Overall and cause-specific mortality among patients with tuberculosis and multidrug-resistant tuberculosis. Int J Tuberc Lung Dis. 2013;17:961–8.
52. 52.
Lin Y-S, Yen Y-F. Determinants of mortality before start of and during tuberculosis treatment among elderly patients: a population-based retrospective cohort study. Age Ageing. 2015;44(3):490–6.
53. 53.
Oliveira Cavalcante EF, Guerreiro Vieira da Silva DM. Profile of Tuberculosis Patients Perfil De Personas Acometidas Por Tuberculosis. Revista da Rede de Enfermagem do Nordeste. 2013;14(4):1–10.Google Scholar
54. 54.
Salinas J, Calvillo S, Caylà J, Nedel FB, Martín M, Navarro A, et al. Delays in the diagnosis of pulmonary tuberculosis in Coahuila, Mexico. Int J Tuberc Lung Dis. 2012;16:1193–8.
55. 55.
Saifodine A, Gudo PS, Sidat M, Black J. Patient and health system delay among patients with pulmonary tuberculosis in Beira city, Mozambique. BMC Public Health. 2013;13:559.
56. 56.
Theron G, Jenkins HE, Cobelens F, Abubakar I, Khan AJ, Cohen T, et al. Data for action: collection and use of local data to end tuberculosis. Lancet. 2015;386:2324–33.
57. 57.
Stevens KB, Pfeiffer DU. Spatial modelling of disease using data- and knowledge-driven approaches. Spat Spatiotemporal Epidemiol. 2011;2:125–33.
Authors and Affiliations
• Luana Seles Alves
• 1
• 9
Email author
• Danielle Talita dos Santos
• 2
• Marcos Augusto Moraes Arcoverde
• 1
• Thais Zamboni Berra
• 1
• Luiz Henrique Arroyo
• 2
• Antônio Carlos Vieira Ramos
• 1
• Ivaneliza Simionato de Assis
• 1
• Ana Angélica Rêgo de Queiroz
• 3
• Jonas Boldini Alonso
• 4
• Josilene Dália Alves
• 2
• Marcela Paschoal Popolin
• 5
• Mellina Yamamura
• 2
• Juliane de Almeida Crispim
• 2
• Elma Mathias Dessunti
• 6
• Pedro Fredemir Palha
• 4
• Francisco Chiaraval-Neto
• 7
• Carla Nunes
• 8
• Ricardo Alexandre Arcêncio
• 4
1. 1.Nursing Graduate Program in Public Health NursingUniversity of São Paulo at Ribeirão Preto Nursing CollegeSão PauloBrazil
2. 2.Inter-institutions Doctoral Program in NursingUniversity of São Paulo at Ribeirão Preto Nursing CollegeSão PauloBrazil
3. 3.Public HealthNatalBrazil
4. 4.University of São Paulo at Ribeirão Preto Nursing CollegeSão PauloBrazil
5. 5.Department of NursingFasipe SchoolMato GrossoBrazil
6. 6.Department of NursingLondrina State UniversityLondrinaBrazil
7. 7.Department of EpidemiologySchool of Public Health, University of São PauloSão PauloBrazil
8. 8.National School of Public HealthNova University of LisbonLisboaPortugal
9. 9.Maternal-Infant and Public Health Nursing DepartmentUniversity of São Paulo at Ribeirão Preto College of NursingRibeirão PretoBrazil | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6877122521400452, "perplexity": 6011.89054455012}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-39/segments/1568514573098.0/warc/CC-MAIN-20190917161045-20190917183045-00136.warc.gz"} |
https://byjus.com/jee/centre-of-mass-of-solid-hemisphere/ | # Centre of Mass of Solid Hemisphere
There is a special point in a system or object, called the centre of mass that moves as if all of the mass of the system is concentrated at that point. The system will move as if an external force is applied to the object of mass M located at the centre of mass. In this article, we will determine the centre of mass of a solid hemisphere.
## How to Find Centre of Mass of Solid Hemisphere
We are considering a solid hemisphere of mass M and has the radius R. The centre of mass will lie on the vertical line passing through the centre of the hemisphere, the vertical line is also the normal to the base. In order to find the centre of mass, we have to consider an element.
We are taking an elemental disc at a height h from the base of the hemisphere. The mass of the elemental disc is dM and the width is dy.
The radius of the disc is $r=\sqrt{R^{2}-y^{2}}$—-(1)
Mass of the disc dM = (3M/2πR3) x (πr2dy)———————-(2)
Substitute equa(1) in equa(2)
dM = (3M/2πR3) x π(R2-y2)dy)
Y-coordinate of Centre of mass,yc= (1/M)ഽydM,
Here y is the y-coordinate which represents the height of the elemental disc from the base.
Putting the value of dM and calculating the centre of mass, we get
yc= (1/M)ഽy(3M/2R3) x (R2-y2)dy)
Integrating between the limits 0⟶R
$y_{c}=\frac{1}{M}\int_{0}^{R}\frac{3M}{R^{3}}(R^{2}-y^{2})dy\times y$
$y_{c}=\frac{3}{2R^{3}}\int_{0}^{R}{}(R^{2}y-y^{3})dy$
= (3/2R2)[(R4/2) – (R4/4)] = 3R/8
yc = 3R/8
Centre of Mass of the solid hemisphere, yc = 3R/8,
Here R is the radius of the hemisphere.
Test Your Knowledge On Centre Of Mass Of Solid Hemisphere! | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8014204502105713, "perplexity": 370.4643212244021}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-39/segments/1631780058589.72/warc/CC-MAIN-20210928002254-20210928032254-00214.warc.gz"} |
https://www.lessonplanet.com/teachers/converting-fractions-to-decimals-a | Converting Fractions to Decimals (A)
In this fractions to decimals conversion worksheet, students write the decimal equivalent beside each common fraction. Students solve 21 problems.
Concepts
Resource Details | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9995636343955994, "perplexity": 17052.96602317483}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-22/segments/1495463608954.74/warc/CC-MAIN-20170527133144-20170527153144-00167.warc.gz"} |
https://stats.stackexchange.com/questions/287407/t-test-p-value-vs-randomization-inference-p-value-what-can-we-learn-from-compar | # t test p value vs randomization-inference p value: What can we learn from comparison?
How can we interpret differences between t test p values and randomization-inference p values?
Let’s say we have a randomized experiment with a binary treatment, denoted $Z_i = 1$ if unit $i$ is assigned to treatment, and outcomes, denoted $Y_i$.
We want test for a treatment effect.
We test both the sharp null hypothesis of no effect and the null hypothesis of no average effect.
Definition $H_{0,sharp}$: Sharp null hypothesis of no effect The treatment effect is zero for all subjects. Formally, $Y_i(1) = Y_i(0)$ for all $i$.
Definition $H_{0,weak}$: Null hypothesis of no average effect (sometimes called the weak null hypothesis) The average treatment effect is zero. Formally, $\mu_{Y(1)} = \mu_{Y(0)}$.
We test $H_{0,sharp}$ using randomization inference (RI) and we test $H_{0,weak}$ with a t test.
If we run these two tests and get different answers, what are useful ways to interpret differences between the t test p value and the RI p value?
Strictly speaking, the two procedures test different hypotheses and they cannot be meaningfully compared, but this is not very useful, and will not satisfy non-specialists (people with substantive rather than technical interest in your research) who want to understand why your results look different when using RI or a t test. Furthermore, the two tests are alternative approaches to answer the same substantive question, “was there a treatment effect?” We should have a guidelines for thinking about different answers to the same substantive question.
A good answer would have a general enough discussion of differences to encompass differences in p values that would lead us to different statistical conclusions (e.g., one test p<0.05 and the other p>0.05) and those that would lead to make the same conclusion from both tests (e.g., both tests p<0.05 or both tests p>0.05).
Notes on RI
For those unfamiliar with RI: The RI p value is calculated by, first, computing the distribution of the test statistic across all (or many) treatment assignments, which is called the null or randomization distribution. The RI p value denotes the proportion of the randomization distribution that is larger than our observed test statistic. (More discussion here, particularly page 5.)
We can conduct RI by calculate the test statistic for all possible permuted treatment assignment vectors (to calculate an exact RI p value) or using a large sample of permuted treatment assignment vectors (to calculate an asymptotic RI p value). As Gerber and Green (2012) write, “Whether one uses all possible randomizations or a large sample of them, the calculation of p values based on an inventory of possible randomizations is called randomization inference.
• Not quite sure what "conventional p-value" means here. I think there are two distinctions to be made: (1) between the average treatment effect's being zero & the effect for each unit's being zero, & (2) between inference based on sampling & inference based on random assignment of treatments. – Scortchi - Reinstate Monica Jun 26 '17 at 16:35
• @Scortchi I'll try to make the question clearer. First, I improved my definition of terms and I changed the adjective from conventional to asymptotic. Another adjectives could be parametric. Is this clear now what p values I'm contrasting to randomization-inference-based p values? – Dr. Beeblebrox Jun 26 '17 at 17:35
• @Dr.Beeblebrox I'd like to edit my answer, but it would be helpful to define some terms. Can you write the so-called sharp null hypothesis out and define the notation? Can you also describe the "randomization inference p-value"? Do you consider Fisher's Exact Test to be a special case of such a p-value? – AdamO Jun 26 '17 at 18:47
• @AdamO I added some notation and defined RI p-value. I didn't add discussion of the relationship to Fisher's Exact Test because of length. On that point, I understand randomization and permutation inference to be modern procedures derived from Fisher's exact test. Perm. Inf. for when you can calculate test statistics for all treatment assignment permutations (that is, for a binary treatment with n subjects, $2^n$ is computationally workable). RI is for when you sample draws from a very large set of $2^n$ treatment asgnmnt vectors. Discussion here stats.stackexchange.com/q/55742/22088 – Dr. Beeblebrox Jun 26 '17 at 19:16
• In general, different answers from different tests can just arise from minute differences. Remember that any test statistic and p-value is just a random variable that will invariably vary even across absolutely identical experiments. So, jumping from just below 0.05 to just over 0.05 for a p-value is a completely meaningless difference, even if some people will wrongly interpret a lot into it. – Björn Apr 18 '18 at 15:28
I think your statement of the randomization inference null hypothesis is incorrect. Or at least, you're confusing two methods to test hypotheses versus two different hypotheses. The randomization test aka the permutation test considers the exact or approximation distribution of test statistics obtained when "labels" are randomly swapped between treatment/control subjects. This can be used to test the weak null hypothesis of no average treatment effect by calculating the t-test statistic for each permuted dataset and evaluating the proportion of these exceeding the one obtained in the unpermuted dataset.
In this working article they frame the hypothesis of treatment effect variation as one of homogeneity where the average treatment effect is considered a nuisance parameter: basically "I don't care whether this drug works, I just want to know if it works differently in some people than it does in others." The effect for the first hypothesis, tested using usually analysis of parallel design, is called average treatment effect (ATE) and the second hypothesis here has been called treatment effect variation (TEV). Testing for TEV smells of a test of effect modification, in the absence of a known effect modifier, and resembles subgroup analysis. Using randomization tests for TEV is a novel and interesting method to consider and is worth reading this article in depth to understand how exactly they formulated such a test.
To summarize how the two hypothesis might agree or disagree in a $2 \times 2$ table:
Case 1: ATE no TEV: the drug works and it has the same potential outcome in everybody regardless. Solution: do not recommend if harmful, consider effect size before recommending approval/use.
Case 2: no ATE no TEV: the drug does not work in anyone. Solution: conclude drug is futile relative to standard of care.
Case 3: no ATE, TEV: the drug works in individuals in such a contrived way that the harm in some and the benefit in others is completely balanced. Solution: identify indicators/contraindicators of harm/benefit subgroups and conduct follow-up study if predicted benefit is of clinical significance.
Case 4: ATE, TEV: the drug shows some average effect but this effect is not the same in everyone. Solution: identify harm groups if any and establish contraindications, predict benefit in remaining group and conduct follow-up study if it is of clinical significance.
• My definition of the RI p value is just derived from a different application of RI than the one you describe. Generally, RI is used to test the sharp null hypothesis of constant treatment effects for all units (which can be used to study variation per the paper you linked); RI can also be used to test the sharp null of no effect for all units, which is the application I am talking about. See here, page 2, mattblackwell.org/files/teaching/s05-fisher.pdf – Dr. Beeblebrox Jun 26 '17 at 18:15
• I edited my question to be more precise – Dr. Beeblebrox Jun 28 '17 at 21:58
I found this discussion of the difference between t-test p values and RI p values helpful, and it speaks to the question I ask above.
Author: Don Green Source: https://egap.org/methods-guides/10-things-randomization-inference
Randomization inference may give different p-values from conventional tests when the number of observations is small and when the distribution of outcomes is non-normal
Conventional p-values typically rely on approximations that presuppose either that the outcomes are normally distributed or that the subject pool is large enough that the test statistics follow a posited sampling distribution. When outcomes are highly skewed, as in the case of donations (a few people donate large sums, but the overwhelming majority donate nothing), conventional methods may produce inaccurate p-values. Gerber and Green, Field Experiments, (2012, p.65) give the following example in which randomization inference and conventional test statistics produce different results: | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7680286169052124, "perplexity": 1206.5881782662411}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-21/segments/1620243988741.20/warc/CC-MAIN-20210506053729-20210506083729-00544.warc.gz"} |
https://codereview.stackexchange.com/questions/217120/trip-planning-algorithm | # Trip planning algorithm
I was presented with an interview question described as follows:
Receiving an int[] A of cities, where each A[i] has an appeal value. We want to plan our trip based on the highest appeal possible, taking in mind that is calculated as follows A[i] + A[j] + (i - j). This means the appeal values of 2 cities summed, plus their distance.
Function signature:
public static int solution(int[] A);
The constraints were the following:
• N is an integer within [1, 100,000]
• A[i] is an integer within [-1,000,000,000, 1,000,000,000]
Using the same value is a possible valid solution, so for example, if we have A = {1, 3, -3}; this should return 6 as visiting city A[0] twice gives the max appeal value A[0] + A[0] + (0 - 0) = 6.
So given that, a possible solution is the same value twice, I did not found other solution than:
int highestAppeal = 0;
for (int i = 0; i < A.length; i++) {
for (int j = 0; j < A.length; j++) {
int currentAppeal = A[i] + A[j] + (i - j);
highestAppeal = currentAppeal > highestAppeal ? currentAppeal : highestAppeal;
}
}
return highestAppeal;
This solution was marked as pretty bad. I realize that a $$\O(n^2)\$$ solution is far from efficient, but in this case, I did not see how to improve it. Later on, I thought about sorting A values in descending order and, for repeated values, using indexes in ascending order. But I don't see that going forward.
What would be a better and more efficient solution for this?
• Well, I've added the expected function signature, so it is clear that an int is expected as result. – Power_of_zero Apr 9 at 12:13
• Ah, sorry, missed that. – TorbenPutkonen Apr 9 at 12:16
• I deleted my answer. I've come to the conclusion that this was a trick question with a purpose of finding out if you notice bad requirements and are able to ask clarifications. – TorbenPutkonen Apr 9 at 12:24
• I had lots of things to ask clarification for, but they sent me as an assignment through a site. I had 2 tasks which I had to do in 1 hour. This was one of them. – Power_of_zero Apr 9 at 12:25
• So, had no contact or any way of asking anything. – Power_of_zero Apr 9 at 12:26
Thinking this more, there are three things affecting the appeal.
• A[i]
• A[j]
• i - j
Since A[i] + A[j] is the same as A[j] + A[i], you don't need to traverse the whole array in the inner loop.
Since the third component increases the appeal only when j < i, you can restrict the inner loop to run from 0 to i.
You also need to take into account the fact that all cities may have negative appeal. Integer.MIN_VALUE is safe initial value, as the lowest valid value (2 * -1000000000 - 100000) is still greater than that.
Using Math.max would have been more readable.
int highestAppeal = Integer.MIN_VALUE;
for (int i = 0; i < A.length; i++) {
for (int j = 0; j <= i; j++) {
final int currentAppeal = A[i] + A[j] + (i - j);
highestAppeal = Math.max(highestAppeal, currentAppeal);
}
}
return highestAppeal;
Yesterday, I asked the interviewers themselves for an efficient solution to this problem, and I finally got one:
int maxStart = A[0];
int maxEnd = A[0];
for (int i = 0; i < A.length; i++) {
if ((A[i] - i) > maxStart) {
maxStart = A[i] - i;
}
if ((A[i] + i) > maxEnd) {
maxEnd = A[i] + i;
}
}
return maxEnd + maxStart;
So this is the O(n) solution they gave me, which I found pretty beautiful to be honest. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 1, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4601287841796875, "perplexity": 1476.8722313902629}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-39/segments/1568514572289.5/warc/CC-MAIN-20190915195146-20190915221146-00155.warc.gz"} |
https://www.physicsforums.com/threads/combining-uncertainties.161181/ | # Combining uncertainties
1. Mar 17, 2007
### swain1
1. The problem statement, all variables and given/known data
If the uncertainty in a measurement of dameter is +-0.02cm is the uncertainty in radius the same or half of this value. The formula given in wikipedia implies that it would be half of the value.
Cheers
2. Relevant equations
3. The attempt at a solution
2. Mar 17, 2007
### nrqed
Yes, it will be half of this value. If the uncertainty had been given in percent form, then the percent uncertainty on the radius and on the diameter would be the same.
3. Mar 17, 2007
### harmeet_angel
2 is a number, and has uncertainty of 0
so, use division rule
4. Mar 17, 2007
### swain1
Ok thanks guys.
I now have to work out the uncertainty in the voume of a sphere using the radius I have. Any clues on how to get the uncertainty in this value? I would expect that it would be bigger but I can't really understand why?
5. Mar 17, 2007
### swain1
I have this formula
deltav/v=3xdeltar/r
Is this correct?
Similar Discussions: Combining uncertainties | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9884890913963318, "perplexity": 1481.1352396481932}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-09/segments/1487501171933.81/warc/CC-MAIN-20170219104611-00578-ip-10-171-10-108.ec2.internal.warc.gz"} |
https://math.meta.stackexchange.com/questions/24924/how-to-make-the-table-fit-better | # How to make the table fit better?
As you can probably see, it is far too long... or wide or whatever.
$$\begin{array} {|c|c|c|c|c|} \hline & \text{Equality} & eq(x,y): & \mathbb{R}\times\mathbb{R}\to\mathbb{B} & 1-|\operatorname{sgn}(x-y)| \\ \hline & \text{Digit At} & dat(x,b,i): & \mathbb{R}\times\mathbb{N}\times\mathbb{Z}\to\mathbb{N} & \left\lfloor\frac{|x|}{b^i}\right\rfloor\mod b \\ \hline & \text{Number of Digits} & nd(x,b): & \mathbb{N}\times\mathbb{N}\to\mathbb{N} & \lceil\log_b(x+1)\rceil \\ \hline & \text{Reverse} & rev(x,b): & \mathbb{N}\times\mathbb{N}\to\mathbb{N} & \sum_{i=0}^{nd(x,b)-1}dat(x,b,I)\cdot10^{nd(x,b)-i-1} \\ \hline & \text{Sum Digits} & sd(x,b): & \mathbb{N}\times\mathbb{N}\to\mathbb{N} & \sum_{i=0}^{nd(x,b)-1}dat(x,b,i)\\ \hline & \text{Look and Say Counter} & C_\lambda(x,i): & \mathbb{N}\times\mathbb{N}\to\mathbb{N} & sd(x\mod10^i,10) \\ \hline & \text{Unpadded Difference} & \delta(x): & \mathbb{N}\to\mathbb{N} & \sum_{i=0}^{nd(x,10)-2}10^i\cdot(1-eq(dat(x,10,i),dat(x,10,i+1))) \\ \hline & \text{Padded Difference} & \Delta(x): & \mathbb{N}\to\mathbb{N} & 10^{nd(x,10)}+10\cdot\delta(x)+1 \\ \hline & \text{Leftmost Index} & il(x,i): & \mathbb{N}\times\mathbb{Z}\to\mathbb{Z} & nd(x\mod10^{i+1},10)-1 \\ \hline & \text{Rightmost Index} & ir(x,i): & \mathbb{N}\times\mathbb{Z}\to\mathbb{Z} & nd(x,10)-nd\left(rev\left(\left\lfloor\frac{x}{10^{i+1}}\right\rfloor,10\right),10\right) \\ \hline & \text{Look and Say} & L(x): & \mathbb{N}\to\mathbb{N} & \sum_{i=0}^{nd(\Delta(x),10)-2}\left(dat(\Delta(x),10,i)\cdot\left(\left(ir(\Delta(x),i)-i\right)\cdot10^{1+2\cdot C_\lambda(\Delta(x),i)}+dat(x,10,i)\cdot10^{2\cdot C_\lambda(\Delta(x),i)}\right)\right) \end{array}$$
Can I make this fit better? Perhaps set a max width to each section and have it warp down when it hits that limiting size?
I previously asked this question here.
• – Mark Booth Nov 7 '16 at 12:07
It strikes me as similar to formatting problems I try to fix in posts, where "run-on equations" (equation chains) laid out in a single line may not wrap well. The worst case is that the mathematical expressions run over into the sidebar and are unreadable. The effect is somewhat dependent on the user's choice of Math Renderer (under Math Settings when you right-click on a MathJax expression).
An example of my editing to split such lines is A Formulation of the Riemann Hypothesis, in which I modified four of the run-on equations.
The MathJax Basic Tutorial and Quick Reference thread here on meta.Math.SE has several mentions of \begin{align} and begin{aligned}. My practice is to use \begin{align*} but I'm not conversant with the finer distinctions among these environments. However see this Answer for a suggestion on formatting a single expression into multiple lines and "columns" of a sort.
So at this point it is just a thought that the contents of the last column of your table could be more narrowly formatted using such an environment. Let me try my hand at demonstrating this for you.
\begin{array} {|c|c|c|c|c|} \hline & \text{Equality} & eq(x,y): & \mathbb{R}\times\mathbb{R}\to\mathbb{B} & 1-|\operatorname{sgn}(x-y)| \\ \hline & \text{Digit At} & dat(x,b,i): & \mathbb{R}\times\mathbb{N}\times\mathbb{Z}\to\mathbb{N} & \left\lfloor\frac{|x|}{b^i}\right\rfloor\mod b \\ \hline & \begin{aligned} \text{Number} \\ \text{of Digits}\end{aligned} & nd(x,b): & \mathbb{N}\times\mathbb{N}\to\mathbb{N} & \lceil\log_b(x+1)\rceil \\ \hline & \text{Reverse} & rev(x,b): & \mathbb{N}\times\mathbb{N}\to\mathbb{N} & \sum_{i=0}^{nd(x,b)-1}dat(x,b,I)\cdot10^{nd(x,b)-i-1} \\ \hline & \text{Sum Digits} & sd(x,b): & \mathbb{N}\times\mathbb{N}\to\mathbb{N} & \sum_{i=0}^{nd(x,b)-1}dat(x,b,i)\\ \hline & \begin{aligned} \text{Look and Say} \\ \text{Counter} \;\;\;\; \end{aligned} & C_\lambda(x,i): & \mathbb{N}\times\mathbb{N}\to\mathbb{N} & sd(x\bmod10^i,10) \\ \hline & \begin{aligned} \text{Unpadded} \\ \text{Difference} \end{aligned} & \delta(x): & \mathbb{N}\to\mathbb{N} & \begin{aligned} \sum_{i=0}^{nd(x,10)-2}10^i\cdot \left[ 1-eq(dat(x,10,i), \\ dat(x,10,i+1))\right] \end{aligned} \\ \hline & \begin{aligned} \text{Padded}\;\; \\ \text{Difference} \end{aligned} & \Delta(x): & \mathbb{N}\to\mathbb{N} & 10^{nd(x,10)}+10\cdot\delta(x)+1 \\ \hline & \begin{aligned} \text{Leftmost}\\ \text{Index} \;\;\; \end{aligned} & il(x,i): & \mathbb{N}\times\mathbb{Z}\to\mathbb{Z} & nd(x\bmod10^{i+1},10)-1 \\ \hline &\begin{aligned} \text{Rightmost}\\ \text{Index} \;\;\;\; \end{aligned} & ir(x,i): & \mathbb{N}\times\mathbb{Z}\to\mathbb{Z} & nd(x,10)-nd\left(rev\left(\left\lfloor\frac{x}{10^{i+1}}\right\rfloor,10\right),10\right) \\ \hline & \text{Look and Say} & L(x): & \mathbb{N}\to\mathbb{N} & \begin{aligned}\sum_{i=0}^{nd(\Delta(x),10)-2}\left[dat(\Delta(x),10,i)\cdot \\ \left( \left(ir(\Delta(x),i)-i\right)\cdot10^{1+2\cdot C_\lambda(\Delta(x),i)} \\ + dat(x,10,i)\cdot10^{2\cdot C_\lambda(\Delta(x),i)}\right)\right] \end{aligned} \\ \hline \end{array}
Above I have not only used the aligned environment in a few last column entries, I also applied the idea to the first (nonempty) column to split text across two lines for some entries. I used a few more tricks for spacing, such as replacing \mod with \bmod.
• I actually borrowed the basic format from the synthetic division comment of the division based answer with 13 likes on it. – Simply Beautiful Art Sep 2 '16 at 1:29 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 1.0000067949295044, "perplexity": 4196.591857664619}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-50/segments/1606141216175.53/warc/CC-MAIN-20201130130840-20201130160840-00381.warc.gz"} |
http://clay6.com/qa/32202/given-the-following-two-statements-which-of-the-following-options-that-foll?show=103924 | Comment
Share
Q)
Given the following two statements, which of the following options that follow is TRUE?
STATEMENT 1: Glucose gives a reddish-brown precipitate with Fehling’s solution.
because
STATEMENT 2: Reaction of Glucose with Fehling’s solution gives CuO and gluconic acid.
$\begin{array}{1 1} \text{(A) Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1} \\ \text{ (B) Statement-1 is True, Statement-2 is True; Statement-2 is NOT a correct explanation for Statement-1} \\ \text{ (C) Statement-1 is True, Statement-2 is False } \\ \text{ (D) Statement-1 is False, Statement-2 is True} \end{array}$
Comment
A)
Toolbox:
• Fehling's test is a chemical test to detect reducing sugars and aldehydes in a solution.
Fehling's test is a chemical test to detect reducing sugars and aldehydes in a solution.
In this test the presence of aldehydes is detected by reduction of the deep blue solution of copper(II) to a red precipitate of insoluble copper oxide. The test is commonly used for reducing sugars.
Fehling's solution is Cupric Oxide CuO, which is blue in colour but changes to red colour precipitate of Cuprous Oxide.
This is illustrated as follows: $C_6H_12O_6$ (Glucose) $+2CuO$ (Cupric Oxide) $\rightarrow C_6H11O5COOH$ (Gluconic Acid) $+ Cu_2O$ (Cuprous Oxide)
We see therefore that Statement 1 is true but Statement 2 is False.
Comment
A)
Glucose contains an Aldehyde group. It reduces Fehling's solution to give red precipitate of $Cu_2O$
$C_6H_{12}O_6$+Fehling solution →$(H_6O_{11}C_7)^−+Cu_2O$↓
$\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;Red \; precipitate$
Hence statement 1 is True and 2 is False | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6613861322402954, "perplexity": 5927.282899201015}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-39/segments/1568514570830.42/warc/CC-MAIN-20190915072355-20190915094355-00281.warc.gz"} |
https://leanprover-community.github.io/mathlib_docs/category_theory/adjunction/reflective.html | Reflective functors #
Basic properties of reflective functors, especially those relating to their essential image.
Note properties of reflective functors relating to limits and colimits are included in category_theory.monad.limits.
@[class]
structure category_theory.reflective {C : Type u₁} {D : Type u₂} (R : D C) :
Type (max u₁ u₂ v₁ v₂)
• to_full :
• to_faithful :
A functor is reflective, or a reflective inclusion, if it is fully faithful and right adjoint.
Instances
theorem category_theory.unit_obj_eq_map_unit {C : Type u₁} {D : Type u₂} {i : D C} (X : C) :
For a reflective functor i (with left adjoint L), with unit η, we have η_iL = iL η.
@[instance]
def category_theory.is_iso_unit_obj {C : Type u₁} {D : Type u₂} {i : D C} {B : D} :
When restricted to objects in D given by i : D ⥤ C, the unit is an isomorphism. In other words, η_iX is an isomorphism for any X in D. More generally this applies to objects essentially in the reflective subcategory, see functor.ess_image.unit_iso.
theorem category_theory.functor.ess_image.unit_is_iso {C : Type u₁} {D : Type u₂} {i : D C} {A : C} (h : A i.ess_image) :
If A is essentially in the image of a reflective functor i, then η_A is an isomorphism. This gives that the "witness" for A being in the essential image can instead be given as the reflection of A, with the isomorphism as η_A.
(For any B in the reflective subcategory, we automatically have that ε_B is an iso.)
theorem category_theory.mem_ess_image_of_unit_is_iso {C : Type u₁} {D : Type u₂} {i : D C} (A : C) :
If η_A is an isomorphism, then A is in the essential image of i.
theorem category_theory.mem_ess_image_of_unit_split_mono {C : Type u₁} {D : Type u₂} {i : D C} {A : C} :
If η_A is a split monomorphism, then A is in the reflective subcategory.
@[instance]
def category_theory.reflective.comp {C : Type u₁} {D : Type u₂} {E : Type u₃} (F : C D) (G : D E) [Fr : category_theory.reflective F] [Gr : category_theory.reflective G] :
Composition of reflective functors.
Equations
def category_theory.unit_comp_partial_bijective_aux {C : Type u₁} {D : Type u₂} {i : D C} (A : C) (B : D) :
(A i.obj B) (i.obj A) i.obj B)
(Implementation) Auxiliary definition for unit_comp_partial_bijective.
Equations
theorem category_theory.unit_comp_partial_bijective_aux_symm_apply {C : Type u₁} {D : Type u₂} {i : D C} {A : C} {B : D} (f : i.obj A) i.obj B) :
The description of the inverse of the bijection unit_comp_partial_bijective_aux.
def category_theory.unit_comp_partial_bijective {C : Type u₁} {D : Type u₂} {i : D C} (A : C) {B : C} (hB : B i.ess_image) :
(A B) (i.obj A) B)
If i has a reflector L, then the function (i.obj (L.obj A) ⟶ B) → (A ⟶ B) given by precomposing with η.app A is a bijection provided B is in the essential image of i. That is, the function λ (f : i.obj (L.obj A) ⟶ B), η.app A ≫ f is bijective, as long as B is in the essential image of i. This definition gives an equivalence: the key property that the inverse can be described nicely is shown in unit_comp_partial_bijective_symm_apply.
This establishes there is a natural bijection (A ⟶ B) ≃ (i.obj (L.obj A) ⟶ B). In other words, from the point of view of objects in D, A and i.obj (L.obj A) look the same: specifically that η.app A is an isomorphism.
Equations
@[simp]
theorem category_theory.unit_comp_partial_bijective_symm_apply {C : Type u₁} {D : Type u₂} {i : D C} (A : C) {B : C} (hB : B i.ess_image) (f : i.obj A) B) :
theorem category_theory.unit_comp_partial_bijective_symm_natural {C : Type u₁} {D : Type u₂} {i : D C} (A : C) {B B' : C} (h : B B') (hB : B i.ess_image) (hB' : B' i.ess_image) (f : i.obj A) B) :
(f h) = h
theorem category_theory.unit_comp_partial_bijective_natural {C : Type u₁} {D : Type u₂} {i : D C} (A : C) {B B' : C} (h : B B') (hB : B i.ess_image) (hB' : B' i.ess_image) (f : A B) :
(f h) = | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8568690419197083, "perplexity": 995.92088459969}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-21/segments/1620243988882.7/warc/CC-MAIN-20210508121446-20210508151446-00541.warc.gz"} |
https://dsp.stackexchange.com/questions/1531/express-a-wave-as-a-sum-of-cosine | # Express a wave as a sum of cosine
I started off with this:
$$x = 5 \cos(200 \times 2 \pi t ) + 10 \cos( 400 \times 2 \pi t)$$
by performing a 1024 point DFT on it. Then I performed IDFT on the complex values obtained through DFT. Now, I want to express the original wave in terms of it's harmonics, so when I combine the DC and first harmonic or upto n harmonics, I get the original wave back. But how do I obtain these harmonics?
This is what I actually want to do. I have some real valued data(144 points). I want to express this data as a sum of cosines. For this purpose, I perform a 144 point DFT operation on this data, and bring them to frequency domain. Does the Euler's identity, give me these cosine?
$$X[k] * e^{\tfrac{j2\pi kn}{144}} + X[144−k] * e^{\tfrac{−j2\pi kn}{144}}$$
• Your cosines are both of the same frequency. Are you sure you wrote down the question correctly? – Phonon Feb 21 '12 at 19:51
• I'm not sure I understand your question. What you want is just the harmonics that represent those two sinusoidal signals? And if I understand correctly, by harmonics you mean the frequency at which each cosine is centered? You want the amplitude and phase of the cosines? I'm not understanding your question :S – El Developer Feb 21 '12 at 22:39
• possible duplicate of Calculate harmonics using DFT from real points – Dilip Sarwate Feb 22 '12 at 0:33
• Discrete Cosine Transform?... – Spacey Feb 22 '12 at 6:48
The Fourier transform converts signals into coefficients of cosines and sines. This is why the coefficients are complex. Simply adding up those two coefficients won't give you sufficient information about the phase (someone can correct me on this statement, but I believe it's true). In other words, for signal of length N you're trying to find coefficients $a_k$ and $b_k$ such that
$$x[n] = \sum_{k=0}^{N/2} a_k \cos(\omega k)+\sum_{k=0}^{N/2} b_k \sin(\omega k)$$
I would suggest using Discrete Cosine Transform (DCT) instead. It literally breaks you signal up into a sum of cosines, it gives you back all real coefficients and it takes care of the phase problem completely.
If you must use Fourier Transform, you should realize that
$$e^{i \omega t} = \cos (\omega t) + i \sin(\omega t)$$
This tells us that we can recreate the even-symmetric component (cosine) from real coefficients of the Fourier Transform, and odd-symmetric component (sine) from imaginary coefficients of the Fourier Transform.
The formula then befomes:
For a given $k$,
$$a_k \cos\left( \frac{2 \pi kn}{N} \right) = \frac{1}{N}\left( \Re (X[k]) e^{ \tfrac{i 2 \pi kn}{N}} + \Re (X[N-k]) e^{ \tfrac{i 2 \pi (N-k)n}{N} } \right),$$
$$b_k \sin\left( \frac{2 \pi kn}{N} \right) = \frac{1}{Ni}\left( \Im (X[k]) e^{ \tfrac{i 2 \pi kn}{N}} + \Im (X[N-k]) e^{ \tfrac{i 2 \pi (N-k)n}{N} } \right),$$
where $\Re(\cdot)$ and $\Im(\cdot)$ represent taking real and imaginary part of a complex number respectively. Note that this is done for each $n \in \{0 \ldots N-1\}$
Note that because of circular symmetry of DFT, $X[N] = X[0]$, so you'll end up adding up the same thing twice according to the formula above. If you do that, then the actual $a_0$ is half of what you get according to the formula above. If you find this division by 2 confusing, this section of Wikipedia article on Fourier Series may provide a better explanation (look for the formula where $a_0$ is divided by 2).
• Beware of lots of typographical errors in the statement: "For each $k$, $$a_k \cos\left( \frac{2 \pi kn}{N} \right) = \Re (X[k]) e^{ \tfrac{i 2 \pi kn}{N}} + \Re (X[N-k]) e^{ \tfrac{i 2 \pi (N-k)n}{N} },$$ $$b_k \sin\left( \frac{2 \pi kn}{N} \right) = \frac{1}{i}\left( \Im (X[k]) e^{ \tfrac{i 2 \pi kn}{N}} + \Im (X[N-k]) e^{ \tfrac{i 2 \pi (N-k)n}{N} } \right),$$ where $\Re(\cdot)$ and $\Im(\cdot)$ represent taking real and imaginary part of a complex number respectively. Note that this is done for each $n \in \{0 \ldots N-1\}$" – Dilip Sarwate Feb 23 '12 at 3:39
• @DilipSarwate I have to be either blind or wrong in my math. Feel free to fix it or post your own answer. – Phonon Feb 23 '12 at 3:45
• @DilipSarwate ...or point out what's wrong. Is it the math or the style? I checked the formula with MATLAB. Recovered the signal fine. – Phonon Feb 23 '12 at 3:49
• I had voted to close this question as a duplicate of another one which had been answered and the (correct) answer there accepted by OP Rakesh. Your answer is wrong because it does not distinguish $X[0]$ must always be treated separately, and when $N$ is even, as it is in this case, $X[N/2]$ must also be must be treated separately. See Hilmar's answer to the other question or Wikipedia. The result is something that looks like your (continued) – Dilip Sarwate Feb 24 '12 at 2:29
• $$x[n] = \sum_{k=0}^{N/2} a_k \cos(\omega k)+\sum_{k=0}^{N/2} b_k \sin(\omega k)$$ which also has typos since the a_0 term is missing. Your assertion that "Note that this is done for each $n \in \{0…N−1\}$" is incorrect; you only need to do it for $1 \leq n \leq (N-1)/2$ and you need to account for $n=0$ and $n=N/2$ (even $N$) separately. – Dilip Sarwate Feb 24 '12 at 2:39 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7950928211212158, "perplexity": 353.30324471799133}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-47/segments/1573496668896.47/warc/CC-MAIN-20191117064703-20191117092703-00228.warc.gz"} |
https://www.physicsforums.com/threads/on-the-set-concept.21435/ | On the set concept
1. Apr 19, 2004
Organic
Earthman: x stands for an actual thing; therefore x cannot be used together with {} if we mean that {} is the notation of the empty set. Shortly speaking, {} is our notation of the empty set and {x} is a general notation for a non-empty set.
Martian:
x stands for general notation of any concept, for example: x=something, x=nothing.
Therefore {x} is our general notation for both empty and non-empty sets.
Earthman:
|{}|=0, |{{}}|=1 and there is no middle state.
Martian: I agree that there is no middle state; therefore we can say that there is a phase transition from {} to {{}} and vise versa.
Earthman: In a non-empty set there can be finitely many or infinitely many elements.
Martian: In a non-empty set there can be finitely many or infinitely many elements, but there is another content which is the opposite of emptiness. We call it fullness and it is notated by {__}, which means that no finitely or infinitely many elements can be found in it. Shortly speaking, it is a one and only one element that cannot be constructed by any collection of points or segments, and |{__}| = 1.
Earthman: What to you mean by no segments. For example: I can take any ___ and find its length by using finitely or infinitely many sub-segments.
Martian: Yes, but in this case you don’t have a one solid ____ but a collection of finitely or infinitely many elements. Shortly speaking, I am not talking about length measurement, but on the structural difference between a "one piece" element, which is not a point, and "many pieces" element.
For example: No broken glass is an unbroken glass.
Earthman: So how can you take ___ as something that can be used by Math Language?
Martian: As I said before: x stands for general notation of any concept, for example: x=something, x=nothing.
Therefore {x} is our general notation for both empty and non-empty sets.
When x is emptiness, we are using it as the unreachable weak limit of Math Language.
When x is fullness, we are using it as the unreachable strong limit of Math Language.
Both emptiness and fullness cannot be used as available inputs for any mathematical system, but they give us the lowest and the highest limits of Math Language.
Shortly speaking, any possible mathematical system can be found between these limits.
Earthman: I understand that emptiness cannot be used as an input, but why fullness cannot be used as an input? After all we have here an existing element.
Martian: You can use fullness only if you break it to pieces of information, but then you have no fullness but finite or infinitely many pieces, and as I explained before, no finite or infinitely many pieces can be in fullness state.
Shortly speaking, |{}|=0, |{a}|=1 and there is no middle state between them.
The same holds for |{a}|=1, |{__}|=1 but as you see, this time the cardinality is the same but {a} is one of many where {__} is The unbroken one, and there is no middle state between them.
2. Apr 19, 2004
Russell E. Rierson
It is clearly self evident, that, if x = something, then x cannot equal ...nothing.
Let x = something
Let not-x = nothing
[ x or not-x] is a tautology
Let [x or not-x] = T(x)
If T(x) then A
If T(not-x) then B
[A or B] = T(T(x))
etc...
A set is a quantity that has an identity that distributes over its elements.
The set of all chickens is predicated by the "chickeness" of its members.
C[a,b,c,...,n] = [Ca, Cb, Cc,...Cn]
The set becomes a nonparadoxical member of itself due to its distributive identity, an informational construct called abstract containment. The abstract contains the concrete as the concrete contains the abstract.
The identity relates to all members of the set. Einstein said that space and time become modes by which we think, not conditions in which we live, if memory serves.
DNA is an algorithm, a finite set of instructions, which can construct a carbon based life form.
The life form physically contains the DNA and the DNA contains the life form in an "abstract" sense.
At a fundamental level of existence, it is postulated that "nature" could be constructed of tiny strings, and those strings, loops, or branes, could even be constructed of string "bits".
These bits could encode information, analogous to the universe's "DNA"? A set of instructions built into the fabric of space/time and mass/energy?
At the most fundamental length scales, the fundamental paticles, called "strings", could be constructed of even more basic units i.e. bits? analogous to a computer code?
1010100010...etc.
Universal algorithms?
This assumption seems to hint for a designed universe, or even stranger still, a universe that is a type of life form...???
Some interesting ideas on "string bits":
http://xxx.lanl.gov/PS_cache/hep-th/pdf/9607/9607183.pdf
http://xxx.lanl.gov/PS_cache/hep-th/pdf/9707/9707048.pdf
According to string theory, the uncertainty in position is given by:
Dx < h/Dp + C*Dp
Which points towards a type of "discrete" spacetime?
So a metric space with distance function r(x,y) involes the real numbers R, allowing the metric space to be embedded in the full structure of manifold, M.
We humans need a quantum field theory of curved spacetime, where the interlocking, discrete, yet causally connected structure of spacetime can be described as a manifold, M, with a metric tensor g_ab. Ergo, the difficulty of formulating a classical background metric is taken care of by the background independence of GR.
Of course the breakdown of the "theory" occurs when spacetime curvature approaches the "Planck" scale. Thus the exact criteria necessary for a valid quantum field theory of curved spacetime requires a quantum theory of gravity. Some potential candidates are loop quantum gravity and string theory...
It appears that a quantum theory of a field system differs from a quantum theory of a particulate system due to the fact that a field system has infinitely many degrees of freedom. Yet, for a system with finitely many degrees of freedom, the kinematic structure of the spacetime in question can be determined by the canonical commutation relations for the position and momentum operators. So the "square matrix" hermitian operators determine up to unitary equivalence the position and momentum observables,
...BUT, it appears there could be problems with formulating a spacetime structure that has infinitely many degrees of freedom.
In general curved spacetime, there does not appear to be any preferred notion of "particles". So for a noncompact space, where the natural notions of particles are available in the asymptotic past and the asymptotic future, the canonical commutation relations corresponding to the two, will, be generally unitarily inequivalent, analogously to the phenomenon of the
ultraviolet catastrophie of quantum electrodynamics.
So if my interpretation is correct, it is necessary to take an algebraic approach, which allows one to consider all states arising in all of the unitarily inequivalent Hilbert space constructions on an equal basis.
So spacetime is locally Euclidean[flat] which allows a universal representation from flat spacetime to curved spacetime, the necessary elements of Poincare symmetry to logically define the canonical commutation relations.
Getting back to the question, "What is a set?", we realize that sets are by definition general entities that correspond to a non-condradictory state of affairs, allowing for meaningful interpretation.
Last edited by a moderator: Apr 20, 2017
3. Apr 19, 2004
WWW
Maybe x is like a wave function of probabilities in QM?
4. Apr 19, 2004
Russell E. Rierson
Excellent point WWW.
A topological space is a set X along with a happy family of subsets of X, called the open sets, requred to satisfy certain conditions, like the empty set and X itself are both open, if the subsets of X, U and V are open, so is the intersection of U and V, of course! And if the sets U_a of X are open, then so is the union of U_a. The collection of sets taken to be open is called the topology of X. An open set containing a point x, which is an element of X, is called a neighborhood of x. The complement of an open set is called "closed".
If M is an m-dimensional manifold and N is an n-dimensional manifold, then M x N is an (m+n) dimensional manifold.
So simultanaety "S" is a spacelike hypersurface or "slice" through spacetime that cuts through event P, with a set of observers having worldlines crossing the simultanaety "simultaneously-orthogonally" having clocks that all read the same "proper" time at the instant of crossing.
The metric spaces are thus defined as being diffeomorphism invariant. Intersecting cotangent bundles[manifolds] are the set of all possible configurations of a system, i.e. they describe the phase space of the system. When the "wave-functions" intersect, and are "in phase", they are at "resonance", giving what is called the "wave-function collapse" of the Schrodinger equation.
So if x is categorized as a general entity, capable of being both something and nothing, it creates a slight problem, in that a general entity is of itself NOT nothing...
5. Apr 19, 2004
WWW
So, I think that the Martian logic is the probability of opposite states (notated as {x}) before we get one and only one of them as the value of x, which is nothing XOR something, in this case.
6. Apr 20, 2004
Russell E. Rierson
First the term "nothing" must be rigorously defined. What is "nothing"?
Nothingness must be approached as a limit. A removal of "somethings", until all that is left is ...nothing.
I prefer to see "nothing" as an infinite symmetry. The Universe and time, is then a sequence of "symmetry breaking".
7. Apr 20, 2004
WWW
Similar Discussions: On the set concept | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.85699063539505, "perplexity": 801.6707307732725}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-05/segments/1516084890874.84/warc/CC-MAIN-20180121195145-20180121215145-00387.warc.gz"} |
http://www.ck12.org/book/CK-12-Algebra-I-Concepts-Honors/r9/section/1.5/ | <meta http-equiv="refresh" content="1; url=/nojavascript/"> Subtraction of Fractions | CK-12 Foundation
You are reading an older version of this FlexBook® textbook: CK-12 Algebra I Concepts - Honors Go to the latest version.
# 1.5: Subtraction of Fractions
Created by: CK-12
Julian and Suz ordered a pizza that was cut into 10 slices. Suz ate 3 slices and Julian ate 4 slices. What fraction of the pizza did each person eat? What fraction of the pizza is left?
### Guidance
$\frac{5}{7}-\frac{2}{7}=?$
The problem can be represented by using fraction strips.
$\boxed{\frac{5}{7}-\frac{2}{7}=\frac{5-2}{7}=\frac{3}{7}}$
To subtract fractions, the fractions must have the same bottom numbers (denominators). Both fractions have a denominator of 7. The answer is the result of subtracting the top numbers (numerators). The numbers in the numerator are 5 and 2. The difference of 5 and 2 is 3. This difference is written in the numerator over the denominator of 7. Therefore $\frac{5}{7}-\frac{2}{7}=\frac{3}{7}$.
When you subtract fractions that have different denominators, you must express the fractions as equivalent fractions with a LCD. Now, subtract the numerators and write the difference over the common denominator.
#### Example A
$\frac{8}{11}-\frac{6}{11}=?$
$\boxed{\frac{8}{11}-\frac{6}{11}=\frac{8-6}{11}=\frac{2}{11}}$
#### Example B
Bessie is measuring the amount of soda in the two coolers in the cafeteria. She estimates that the first cooler is $\frac{2}{3}$ full and the second cooler is $\frac{1}{4}$ full. What single fraction could Bessie use to represent how much more soda is in the first cooler than in the second cooler?
Use fraction strips to represent each fraction.
$\frac{2}{3}$ and $\frac{8}{12}$ are equivalent fractions. $\frac{2}{3} \left(\frac{4}{4}\right)=\frac{8}{12}$.
$\frac{1}{4}$ and $\frac{3}{12}$ are equivalent fractions. $\frac{1}{4} \left(\frac{3}{3}\right)=\frac{3}{12}$.
The two green pieces will be replaced with eight purple pieces and the one blue piece will be replaced with three purple pieces.
The denominator of 12 is the LCD (least common denominator) of $\frac{2}{3}$ and $\frac{1}{4}$ because it is the LCM (least common multiple) of the denominators 3 and 4.
#### Example C
A number line can also be used to subtract fractions. In the following example, a mixed number which is a whole number and a fraction will be added to a fraction by using a $\frac{1}{4}$ number line.
$1 \frac{3}{4}-\frac{1}{2}$
The number line is labeled in intervals of 4 which indicates that each interval represents $\frac{1}{4}$. From zero, move to the number 1 plus 3 more intervals to the right. Mark the location. This represents $1 \frac{3}{4}$.
From here, move to the left $\frac{1}{2}$ or $\frac{1}{2}$ of 4, which is 2 intervals. An equivalent fraction for $\frac{1}{2}$ is $\frac{2}{4}$.
The difference of $1 \frac{3}{4}$ and $\frac{1}{2}$ is $1 \frac{1}{4}$.
#### Concept Problem Revisited
Julian and Suz ordered a pizza that was cut into 10 slices. Suz ate 3 slices and Julian ate 4 slices. What fraction of the pizza did each person eat? What fraction of the pizza is left?
Suz at $\frac{3}{10}$ of the pizza because she ate 3 out of the 10 slices. Julian ate $\frac{4}{10}$ of the pizza. Together they ate $\frac{7}{10}$ of the pizza. $\frac{10}{10}-\frac{7}{10}=\frac{3}{10}$. Therefore, $\frac{3}{10}$ of the pizza is left.
### Vocabulary
Denominator
The denominator of a fraction is the number on the bottom that indicates the total number of equal parts in the whole or the group. $\frac{5}{8}$ has denominator 8.
Fraction
A fraction is any rational number that is not an integer.
LCD
The least common denominator is the lowest common multiple of the denominators of two or more fractions. The least common denominator of $\frac{3}{4}$ and $\frac{1}{5}$ is 20.
LCM
The least common multiple is the lowest common multiple that two or more numbers share. The least common multiple of 6 and 5 is 30.
Numerator
The numerator of a fraction is the number on top that is the number of equal parts being considered in the whole or the group. $\frac{5}{8}$ has numerator 5.
### Guided Practice
1. Use a model to answer the problem $\frac{7}{10}-\frac{2}{5}=?$
2. Use a number line to determine the answer to the problem $\frac{7}{8}-\frac{1}{2}$.
3. Determine the answer to $\frac{5}{8}-\frac{1}{3}=?$ and $\frac{4}{5}-\frac{1}{4}=?$ by using the rules for subtracting fractions.
1.
Use fraction strips to represent each fraction.
The fractions do not have a common denominator. An equivalent fraction for $\frac{2}{5}$ is $\left(\frac{2}{2}\right) \left(\frac{2}{5}\right)=\frac{4}{10}$
When four strips have been removed from $\frac{7}{10}$, there are $\frac{3}{10}$ remaining.
$\boxed{\frac{7}{10}-\frac{4}{10}=\frac{7-4}{10}=\frac{3}{10}}$
2. $\frac{7}{8}-\frac{1}{2}$
Use a $\frac{1}{8}$ number line. The number line is labeled in intervals of 8. Place the starting point at $\frac{7}{8}$.
From this point, move to the left a total of 4 intervals. $\frac{1}{2}$ of $8=4$. An equivalent fraction for $\frac{1}{2}$ is $\frac{1}{2} \left(\frac{4}{4} \right)=\frac{4}{8}$. The point where you stop is the difference of $\frac{7}{8}$ and $\frac{1}{2}$.
On the number line you stopped at the point $\frac{3}{8}$. This is equal to $\frac{7}{8}-\frac{4}{8}=\frac{7-4}{8}=\frac{3}{8}$.
3. $\frac{5}{8}-\frac{1}{3}=?$
The least common multiple of 8 and 3 is 24. This means that both fractions must have a common denominator of 24 before they can be subtracted.
$\frac{5}{8} \left(\frac{3}{3}\right)=\frac{15}{24}$
$\frac{1}{3} \left(\frac{8}{8}\right)=\frac{8}{24}$
$& \frac{5}{8}-\frac{1}{3}\\& \frac{15}{24}-\frac{8}{24}\\& =\frac{15-8}{24}=\frac{7}{24}$
$\frac{4}{5}-\frac{1}{4}=?$
The least common multiple of 5 and 4 is 20. This means that both fractions must have a common denominator of 20 before they can be added.
$\frac{4}{5} \left(\frac{4}{4}\right)=\frac{16}{20}$
$\frac{1}{4} \left(\frac{5}{5}\right)=\frac{5}{20}$
$& \frac{4}{5}-\frac{1}{4}\\& \frac{16}{20}-\frac{5}{20}\\& =\frac{16-5}{20}=\frac{11}{20}$
### Practice
Use fraction strips to represent the following subtraction problems and use that model to determine the answer.
1. $\frac{3}{4}-\frac{5}{8}$
2. $\frac{4}{5}-\frac{2}{3}$
3. $\frac{5}{9}-\frac{2}{3}$
4. $\frac{6}{7}-\frac{2}{3}$
5. $\frac{7}{10}-\frac{1}{5}$
Use a number line to represent the following subtraction problems and use the number line to determine the answer.
1. $\frac{2}{3}-\frac{1}{2}$
2. $\frac{3}{5}-\frac{3}{10}$
3. $\frac{7}{9}-\frac{1}{3}$
4. $\frac{5}{8}-\frac{1}{4}$
5. $\frac{2}{5}-\frac{2}{10}$
Use the rules that you have learned for subtracting fractions to answer the following problems.
1. $\frac{7}{11}-\frac{1}{2}$
2. $\frac{5}{8}-\frac{5}{12}$
3. $\frac{5}{6}-\frac{3}{4}$
4. $\frac{5}{6}-\frac{2}{5}$
5. $\frac{4}{5}-\frac{3}{4}$
For each of the following questions, write a subtraction statement and find the result.
1. Sally used $\frac{2}{3} \ cups$ of flour to make cookies. Terri used $\frac{1}{2} \ cups$ of flour to make a cake. Who used more flour? How much more flour did she use?
2. Lauren used $\frac{3}{4} \ cup$ of milk, $1 \frac{1}{3} \ cups$ of flour and $\frac{3}{8} \ cup$ of oil to make pancakes. Alyssa used $\frac{3}{8} \ cup$ of milk, $2 \frac{1}{4} \ cups$ of flour and $\frac{1}{3} \ cup$ of melted butter to make waffles. Who used more cups of ingredients? How many more cups of ingredients did she use?
3. Write two fractions with different denominators whose difference is $\frac{3}{8}$. Use fraction strips to model your answer.
4. Jake’s dog ate $12 \frac{2}{3} \ cans$ of food in one week and $9 \frac{1}{4} \ cans$ the next week. How many more cans of dog food did Jake’s dog eat in week one?
5. Sierra and Clark each solved the same problem.
Sierra’s Solution
$& \frac{3}{4}-\frac{1}{6}\\& \frac{9}{12}-\frac{2}{12}\\& =\frac{7}{12}$
Clark’s Solution
$& \frac{3}{4}-\frac{1}{6}\\& \frac{9}{12}-\frac{2}{12}\\& =\frac{7}{0}$
Who is correct? What would you tell the person who has the wrong answer?
## Date Created:
Jan 16, 2013
Nov 13, 2013
You can only attach files to Modality which belong to you
If you would like to associate files with this Modality, please make a copy first. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 91, "texerror": 0, "math_score": 0.8210896253585815, "perplexity": 737.7754947531242}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-15/segments/1398223206147.1/warc/CC-MAIN-20140423032006-00319-ip-10-147-4-33.ec2.internal.warc.gz"} |
https://tex.stackexchange.com/questions/420498/extract-convert-store-and-reuse-x-y-coordinate-components?noredirect=1 | # Extract, convert, store and reuse (x,y) coordinate components
On a beamer frame, I have two tikzpicture environments one below the other. Both use the axis environment with identical scaling and domains. I need to:
1. Extract some coordinate from the picture on top.
2. Convert such coordinate to axis cs: and print its x and y components on the picture.
3. Store the converted (x,y) components.
4. Use the converted (x,y) components in the subsequent tikzpicture environment.
I have already tried to tackle these issues through the solutions that have been proposed to some related problems, such as Coordinates of intersections and Extract x, y coordinate of an arbitrary point in TikZ. While admittedly not addressing all of the four points above, the solutions I have consulted typically extract only one of the coordinate components and/or do not jointly tackle the issue of conversion to axis cs:. Instead, I need both coordinate components to be extracted and converted. Moreover, I need to reuse such components in the subsequent tikzpicture environment.
I attach hereby a MWE and the resulting outcome (except for the callout). The comments to the script provide further details to my question.
\documentclass{beamer}
\usepackage[mode=buildnew]{standalone}
% Drawing
\usepackage{tikz,tkz-graph}
\usetikzlibrary{intersections,positioning}
\tikzset{>=latex}
\usepackage{pgfplots}
\begin{document}
\begin{frame}
\frametitle{Frame title}
\centering
% Top picture
\begin{tikzpicture}[
baseline=(current bounding box.north),
trim axis left,
trim axis right
]
\begin{axis}[
width=5cm,
xmin=0,
xmax=24,
ymin=-8,
ymax=16,
xtick={10},
xticklabels={$y_e=10$},
ytick={10},
yticklabels={$r_S=10$},
clip=true
]
% Constant parameters
\pgfmathsetmacro{\isv}{22.5}
\pgfmathsetmacro{\k}{1.25}
\pgfmathsetmacro{\ye}{10}
\pgfmathsetmacro{\rs}{10}
% Vertical line corresponding to ye
\addplot [name path=ye,red] coordinates {(\ye,\pgfkeysvalueof{/pgfplots/ymin}) (\ye,\pgfkeysvalueof{/pgfplots/ymax})};
% Horizontal line corresponding to rs
\addplot [name path=rs,red] coordinates {(\pgfkeysvalueof{/pgfplots/xmin},\rs) (\pgfkeysvalueof{/pgfplots/xmax},\rs)};
% Downward sloping IS curve
\addplot [name path=is,smooth,very thick,domain=\pgfkeysvalueof{/pgfplots/xmin}:\pgfkeysvalueof{/pgfplots/xmax}] {\isv-\k*x} node [anchor=west,pos=0.85] {$IS$};
% Seek the intersection between the ye line and IS and label the point of intersection as A
\path [name intersections={of=ye and is,by={A}}] node [anchor=south west,xshift=-1mm,yshift=-1mm] at (A) {$A$};
% Get the coordinates of point A
\pgfgetlastxy{\Ax}{\Ay}
% Print the coordinates next to the A label
\node [anchor=south west,xshift=2mm,yshift=-1mm] at (A) {\tiny (\Ax,\Ay)}; % <-- Step 1: I need both the x and y components to be expressed (and subsequently stored) in terms of the axis coordinate system (i.e. 'axis cs:'). Also, I still do not understand why the command pints (0.0pt,0.0pt) instead of the standard coordinates of A.
\end{axis}
\end{tikzpicture}
% Bottom picture
\begin{tikzpicture}[
baseline=(current bounding box.north),
trim axis left,
trim axis right
]
\begin{axis}[
width=5cm,
xmin=0,
xmax=24,
ymin=-14,
ymax=10,
xtick={10},
xticklabels={$y_e$},
ytick={2},
yticklabels={$\pi^T$}
]
% Constant parameters
\pgfmathsetmacro{\a}{0.5}
\pgfmathsetmacro{\pe}{2}
\pgfmathsetmacro{\pt}{2}
\pgfmathsetmacro{\ye}{10} % <-- Step 2: I need to specify at least this number as the \Ax coordinate derived from the tikzpciture above. If possible, it would be nice to insert \Ax also in the xtick list.
% Upward sloping PC curve
\addplot [name path=pc,color=black,very thick,domain=\pgfkeysvalueof{/pgfplots/xmin}:\pgfkeysvalueof{/pgfplots/xmax}] {\pe+\a*(x-\ye)} node [anchor=north,pos=0.85] {$PC$};
% Vertical line corresponding to ye
\addplot [name path=ye,red] coordinates {(\ye,\pgfkeysvalueof{/pgfplots/ymin}) (\ye,\pgfkeysvalueof{/pgfplots/ymax})};
\end{axis}
\end{tikzpicture}
\end{frame}
\end{document}
COMPLETE REVISION: ... after some iterations. A similar question has been answered here. Rewriting the code of this answer such that it also computes the y coordinates leads to this answer.
\documentclass{beamer}
\usepackage[mode=buildnew]{standalone}
% Drawing
\usepackage{tikz,tkz-graph}
\usetikzlibrary{intersections,positioning}
\tikzset{>=latex}
\usepackage{pgfplots}
% from https://tex.stackexchange.com/a/170243/121799
\newlength{\lenx}
\newlength{\plotwidth}
\newlength{\leny}
\newlength{\plotheight}
\newcommand{\getvalue}[1]{\pgfkeysvalueof{/pgfplots/#1}}
%output will be given by \pgfmathresult
\newcommand{\Getxycoords}[3]% #1 = node name, #2 x coordinate, #2 y coordinate
{\pgfplotsextra{%
\pgfextractx{\lenx}{\pgfpointdiff{\pgfplotspointaxisxy{0}{0}}{\pgfpointanchor{#1}{center}}}%
\pgfextractx{\plotwidth}{\pgfpointdiff{\pgfplotspointaxisxy{\getvalue{xmin}}{0}}%
{\pgfplotspointaxisxy{\getvalue{xmax}}{0}}}%
\pgfextracty{\leny}{\pgfpointdiff{\pgfplotspointaxisxy{0}{0}}{\pgfpointanchor{#1}{center}}}%
\pgfextracty{\plotheight}{\pgfpointdiff{\pgfplotspointaxisxy{0}{\getvalue{ymin}}}%
{\pgfplotspointaxisxy{0}{\getvalue{ymax}}}}%
\pgfmathsetmacro{\myx}{\lenx*(\getvalue{xmax}-\getvalue{xmin})/\plotwidth}%
\pgfmathsetmacro{\myy}{\leny*(\getvalue{ymax}-\getvalue{ymin})/\plotheight}%
\xdef#2{\myx}
\xdef#3{\myy}
%\typeout{\myx,\myy} <- for debugging
}}
\begin{document}
\begin{frame}
\frametitle{Frame title}
\centering
% Top picture
\begin{tikzpicture}[
baseline=(current bounding box.north),
trim axis left,
trim axis right
]
\begin{axis}[
width=5cm,
xmin=0,
xmax=24,
ymin=-8,
ymax=16,
xtick={10},
xticklabels={$y_e=10$},
ytick={10},
yticklabels={$r_S=10$},
clip=true
]
% Constant parameters
\pgfmathsetmacro{\isv}{22.5}
\pgfmathsetmacro{\k}{1.25}
\pgfmathsetmacro{\ye}{10}
\pgfmathsetmacro{\rs}{10}
% Vertical line corresponding to ye
\addplot [name path=ye,red] coordinates {(\ye,\pgfkeysvalueof{/pgfplots/ymin}) (\ye,\pgfkeysvalueof{/pgfplots/ymax})};
% Horizontal line corresponding to rs
\addplot [name path=rs,red] coordinates {(\pgfkeysvalueof{/pgfplots/xmin},\rs) (\pgfkeysvalueof{/pgfplots/xmax},\rs)};
% Downward sloping IS curve
\addplot [name path=is,smooth,very thick,domain=\pgfkeysvalueof{/pgfplots/xmin}:\pgfkeysvalueof{/pgfplots/xmax}] {\isv-\k*x} node [anchor=west,pos=0.85] {$IS$};
% Seek the intersection between the ye line and IS and label the point of intersection as A
\path [name intersections={of=ye and is,by={A}}] node [anchor=south west,xshift=-1mm,yshift=-1mm] at (A) {$A$}
\pgfextra{\pgfgetlastxy{\myx}{\myy}
\xdef\Absolutex{\myx}
\xdef\Absolutey{\myy}
};
\draw[blue,fill] (A) circle (2pt);
% Get the coordinates of point A
\Getxycoords{A}{\Ax}{\Ay}
\end{axis}
\node[anchor=south west,xshift=0.2cm,yshift=1.1cm, text width=3.7cm,
font=\tiny,draw] (explain) at (A){%
the node has plot coordinates (\Ax,\Ay) and absolute coordinates
(\Absolutex,\Absolutey)};
\draw[gray,-latex] (explain) to[out=-90,in=90] (A);
\end{tikzpicture}
% Bottom picture
\begin{tikzpicture}[
baseline=(current bounding box.north),
trim axis left,
trim axis right
]
\begin{axis}[
width=5cm,
xmin=0,
xmax=24,
ymin=-14,
ymax=10,
xtick={10},
xticklabels={$y_e$},
ytick={2},
yticklabels={$\pi^T$},
enlargelimits=0.1 %<-1
]
% Constant parameters
\pgfmathsetmacro{\a}{0.5}
\pgfmathsetmacro{\pe}{2}
\pgfmathsetmacro{\pt}{2}
\pgfmathsetmacro{\ye}{\Ax} % <-- Step 2: I need to specify at least this number as the \Ax coordinate derived from the tikzpciture above. If possible, it would be nice to insert \Ax also in the xtick list.
% Upward sloping PC curve
\addplot [name path=pc,color=black,very thick,domain=\pgfkeysvalueof{/pgfplots/xmin}:\pgfkeysvalueof{/pgfplots/xmax}] {\pe+\a*(x-\ye)} node [anchor=north,pos=0.85] {$PC$};
% Vertical line corresponding to ye
\addplot [name path=ye,red] coordinates {(\ye,\pgfkeysvalueof{/pgfplots/ymin}) (\ye,\pgfkeysvalueof{/pgfplots/ymax})};
\node [label=south:{\tiny (\Ax,\Ay)}] (B) at (axis cs:\Ax,\Ay){};
\Getxycoords{B}{\Bx}{\By}
\draw[blue,fill] (B) circle (2pt);
\end{axis}
\typeout{debug:\space\Bx,\By}
\end{tikzpicture}
\end{frame}
\end{document}
In addition, the absolute coordinates are computed. Both are shown in the upper plot.
• I had clearly misunderstood the functioning of \pgfgetlastxy. Your answer also makes clear that whichever coordinate is saved in the first picture remains defined also for the second picture. Hence, my question ultimately boils down to a conversion issue. That is, I need \Ax and \Ay to be converted to the axis cs: coordinate system, thus generating two new coordinate components (\AxCS,\AyCS). This would allow me, for instance, to insert the resulting numbers in a line such as \pgfmathsetmacro{\ye}{\AxCS} in the second picture. – Brocardo Reis Mar 16 '18 at 13:41
• To further clarify, the accepted answer to Convert from physical dimensions to axis cs coordinate values provides a way to transform the floating point associated to \Ax into the corresponding axis cs: coordinate component. Unfortunately, I fail to adapt that code so as to do the same also for \Ay. – Brocardo Reis Mar 16 '18 at 14:12
• @BrocardoReis Yes, I know, see my revised answer. ;-) – marmot Mar 16 '18 at 14:22
• Your updated answer solves the problem of getting both the x- and y-component of the coordinate. However, to stick to the my original question, you should update it by defining \pgfmathsetmacro{\ye}{\Ax} in the second picture instead of \pgfmathsetmacro{\ye}{\Ay}. Also, something is wrong with the blue arrow: its origin should correspond exactly to (\Ax,\Ay), I think. At any rate, to simplify matters feel free to edit both my question and your answers to some common range that will fit all necessary points. – Brocardo Reis Mar 16 '18 at 14:36
• @BrocardoReis I updated my answer. The reason why B was at the wrong spot was that nodes are extended objects. I fixed this by using a label to display the coordinates. And I did not really have to modify your setting, I only added enlargelimits=0.1 to the options of the second plot such that the coordinate is shown. – marmot Mar 16 '18 at 14:52
With the release of PGFPlots v1.16 it is now possible to store (axis) coordinates with \pgfplotspointgetcoordinates in data point, which then can be called by \pgfkeysvalueof or \pgfkeysgetvalue. With this it is quite simple to adapt/simplify the \Getxycoords macro given in marmot's answer.
% used PGFPlots v1.16
\documentclass[border=5pt,varwidth]{standalone}
\usepackage{pgfplots}
\usetikzlibrary{
intersections,
}
% create a custom style to store common axis' options
\pgfplotsset{
my axis style/.style={
width=5cm,
xmin=0,
xmax=24,
domain=\pgfkeysvalueof{/pgfplots/xmin}:\pgfkeysvalueof{/pgfplots/xmax},
samples=2,
clip mode=individual,
},
}
% ---------------------------------------------------------------------
% Coordinate extraction
% #1: node name
% #2: output macro name: x coordinate
% #3: output macro name: y coordinate
\newcommand{\Getxycoords}[3]{%
\pgfplotsextra{%
% using \pgfplotspointgetcoordinates' stores the (axis)
% coordinates in data point' which then can be called by
% \pgfkeysvalueof' or \pgfkeysgetvalue'
\pgfplotspointgetcoordinates{(#1)}%
% \global' (a TeX macro and not a TikZ/PGFPlots one) allows to
% store the values globally
\global\pgfkeysgetvalue{/data point/x}{#2}%
\global\pgfkeysgetvalue{/data point/y}{#3}%
}%
}
% ---------------------------------------------------------------------
\begin{document}
\raggedleft
% Top picture
\begin{tikzpicture}
\begin{axis}[
my axis style,
%
ymin=-8,
ymax=16,
xtick={10},
xticklabels={$y_e=10$},
ytick={10},
yticklabels={$r_S=10$},
]
% Constant parameters
\pgfmathsetmacro{\isv}{22.5}
\pgfmathsetmacro{\k}{1.25}
\pgfmathsetmacro{\ye}{10}
\pgfmathsetmacro{\rs}{10}
% Vertical line corresponding to ye
(\ye,\pgfkeysvalueof{/pgfplots/ymin})
(\ye,\pgfkeysvalueof{/pgfplots/ymax})
};
% Horizontal line corresponding to rs
(\pgfkeysvalueof{/pgfplots/xmin},\rs)
(\pgfkeysvalueof{/pgfplots/xmax},\rs)
};
% Downward sloping IS curve
name path=is,
smooth,
very thick,
] {\isv-\k*x}
node [anchor=west,pos=0.85] {$IS$}
;
% Seek the intersection between the ye line and IS and label the point of intersection as A
\path [name intersections={of=ye and is,by={A}}]
node [anchor=south west,xshift=-1mm,yshift=-1mm] at (A) {$A$}
;
% Get the coordinates of point A
\Getxycoords{A}{\Ax}{\Ay}
% Print the coordinates next to the A label
\node [
anchor=south west,
xshift=2mm,
yshift=-1mm,
/pgf/number format/precision=3,
] at (A) {\tiny (%
\pgfmathprintnumber{\Ax},%
\pgfmathprintnumber{\Ay}%
)};
\end{axis}
\end{tikzpicture}
% Bottom picture
\begin{tikzpicture}
\begin{axis}[
my axis style,
%
ymin=-14,
ymax=10,
xtick={\Ax}, % the stored value can used (almost) wherever you want
xticklabels={$y_e$},
ytick={2},
yticklabels={$\pi^T$},
]
% Constant parameters
\pgfmathsetmacro{\a}{0.5}
\pgfmathsetmacro{\pe}{2}
\pgfmathsetmacro{\pt}{2}
\pgfmathsetmacro{\ye}{\Ax} % of course also here
% Upward sloping PC curve
name path=pc,
very thick,
] {\pe+\a*(x-\ye)}
node [anchor=north,pos=0.85] {$PC$}
;
% Vertical line corresponding to ye | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9178228378295898, "perplexity": 6204.796620102151}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-30/segments/1563195526446.61/warc/CC-MAIN-20190720045157-20190720071157-00211.warc.gz"} |
http://perlguru.com/gforum.cgi?post=404;sb=post_replies;so=DESC;forum_view=forum_view_collapsed;page=last;guest= | CGI/Perl Guide | Learning Center | Forums | Advertise | Login Site Search: in Perl Guide PerlGuru Forums Learning Ctr
Home: Perl Programming Help: Beginner:
is there a way to compile perl to binary exe.
brian.hayes
User
Jan 22, 2000, 7:47 PM
Post #1 of 15 (1786 views)
is there a way to compile perl to binary exe. Can't Post
Hello again,
I have noticed that there is no compiler in perl to create static exe files. Like gcc or vb6, etc...
Is there a way to do this?
Brian Hayes
brian.hayes
User
Jan 22, 2000, 7:51 PM
Post #2 of 15 (1786 views)
Re: is there a way to compile perl to binary exe. [In reply to] Can't Post
Almost forgot. Does perl take advantage of a smp system. More than one processor?
Borderline
Deleted
Jan 22, 2000, 11:30 PM
Post #3 of 15 (1786 views)
Re: is there a way to compile perl to binary exe. [In reply to] Can't Post
There is no viable way to compile a Perl script into executable format.
There is one module that converts it to C code but it is (according to the auther) not great C code. The module is called B and is by Malcolm Beattie. It is currently in Alpha 2 state of developement. You can find it on CPAN.
I am not familar with Duel Processor ops at all. Sorry.
Scott
brian.hayes
User
Jan 23, 2000, 4:47 AM
Post #4 of 15 (1786 views)
Re: is there a way to compile perl to binary exe. [In reply to] Can't Post
Found the answere to the SMP processor issue.
Perl needs to be recompiled. Perl creates a sytem dependant arch. directory under the main perl directory which contains the core build. I.E i686-Linux.
Please note I have not have any issues with perl when using the i386-linux build. "Single processor build" on my multiple processor system.
Brian Hayes.
Jasmine
Jan 26, 2000, 8:48 PM
Post #5 of 15 (1786 views)
Re: is there a way to compile perl to binary exe. [In reply to] Can't Post
Brian,
Check out Perl2Exe. I've never tried it, but have seen a lot of ads for it in the Perl Journal
Perl2Exe's site says:
Perl2Exe is a command line utility for converting perl scripts to executable files.
This allows you to create stand alone programs in perl that do not require the perl interpreter. You can also ship the executable file without having to ship your perl source code.
Perl2Exe can generate executables for Win32 and Unix target hosts.
Perl2Exe also allows you to create no-console programs using Tk.
It says that it supports Linux, SunOS, BSDOS, IRIX, HP-UX, AIX, and FreeBSD and ActivePerl.
If you do decide to use it, would you mind telling us how you like it?
brian.hayes
User
Jan 27, 2000, 4:54 AM
Post #6 of 15 (1786 views)
Re: is there a way to compile perl to binary exe. [In reply to] Can't Post
Hello again,
Thanks for the lead I will check that one out. I also found some information on another way to compile perl code. It still is somewhat beta but ships with 5.005 perl.
B::Bytecode, B::C, and B:CC. These will produce code respectfully. B::C creates C code so that you can compile using a C compiler.
Perl.com says:
The standard release comes with a perlcc tool to help manage the back-end code generators.
Three different code generators are supported:
B::Bytecode -- Perl compiler's bytecode backend
B::C -- Perl compiler's C backend
B::CC -- Perl compiler's optimized C translation backend
Also, Perlcc tool that ships with 5.005. This one will compile the code for you and will give you the option to include the Lib files for stand alone exe's. I belive it replaces the perl2exe.
perl.com says:
'perlcc' is the frontend into the perl compiler.
Typing 'perlcc a.p' compiles the code inside a.p into a standalone executable,
and perlcc A.pm will compile into a shared object, A.so,
suitable for inclusion into a perl program via ``use A''.
Usage:
%prompt perlcc a.p b.p c.p -regex 's/\.p/\.exe'
# compiles into 'a.exe','b.exe','c.exe'.
I will do some more test with this and give more detailed feed back.
Thanks for the help.
Brian Hayes
brian.hayes
User
Jan 28, 2000, 8:27 PM
Post #7 of 15 (1786 views)
Re: is there a way to compile perl to binary exe. [In reply to] Can't Post
Still working on this one. It seems that this is in VERY Beta.. Every time I try to compile I get:
"Error can't open !".
Did have luck on the B::C module..
Succesfully created and compiled some c code,
But seems to die on big code perl code. Ther again this could be user error.
Brian Hayes
Cure
User
Jan 31, 2000, 2:09 PM
Post #8 of 15 (1786 views)
Re: is there a way to compile perl to binary exe. [In reply to] Can't Post
I have a win32 operating system..
I installed the Perl2Exe on my computer and it compiled my cgi program to a .exe file(stand-alone) and it worked...
p.s. larry Wall must be God..........
Cure
User
Jan 31, 2000, 2:14 PM
Post #9 of 15 (1786 views)
Re: is there a way to compile perl to binary exe. [In reply to] Can't Post
brian.hayes i Got this error also "Error can't open !".
Solution-> you need to put your .cgi or .pl in the same directory as your Perl2Exe or tell Perl2Exe the path to your .cgi or .pl that your trying to compile.
brian.hayes
User
Jan 31, 2000, 6:10 PM
Post #10 of 15 (1786 views)
Re: is there a way to compile perl to binary exe. [In reply to] Can't Post
Thanks for the help...I am using the ActiveState version of perl to attempt this before attempting on Linux.
ActiveSate version requires a download of the Dev kit to have the abilty to compile code. This was succesfull, except I now need to figure out how to get IIS to run the program instead of downloading it.
It is now called perlapp instead of perl2exe.
Thanks again,
Brian Hayes
brian.hayes
User
Jan 31, 2000, 6:48 PM
Post #11 of 15 (1786 views)
Re: is there a way to compile perl to binary exe. [In reply to] Can't Post
Correction perlapp is bundled with Activestate perl dev kit. perl2exe is another company.
brian.hayes
User
Jan 31, 2000, 7:01 PM
Post #12 of 15 (1786 views)
Re: is there a way to compile perl to binary exe. [In reply to] Can't Post
How to for ActiveStates devkit compiler for perl scripts. Please goto activestate.com and read the licence agreement.
First Copy the script to the bin directory and type:
C:\perl\bin\perl perlapp.pl -dependant yourscript.pl
Note -dependant will create an exe that is dependant on perl being installed. You must purchase a license for the compiler to create standalone apps using this.
Once created just copy the newly created yourscript.exe to your equivilant of a Apache cgi-bin directory and point your browser at it. Meaning create a virtual Directory from the Admin Snapin and set the execute(including script) on that directory.
The test that I used included CGI.pl and the LWP.pl bundle or LWP::UserAgent.pm.
TESTED SUCSESSFULLY! Good luck to all on this one.
Brian Hayes
Cure
User
Feb 1, 2000, 2:52 PM
Post #13 of 15 (1786 views)
Re: is there a way to compile perl to binary exe. [In reply to] Can't Post
I also have activeperl and all I had to do to compile a perl script is the follwing:
1.Install perl2exe
2. go to your ms-dos prompt then go to the directory where you installed perl2exe, then type perl2exe and the path to the script you want to compile
I installed my perl2exe into a directory I created called perlexe
example(this what i do)
c:\perlexe\perl2exe cure.cgi
and it compiles my script just fine.
brian.hayes
User
Feb 1, 2000, 6:12 PM
Post #14 of 15 (1786 views)
Re: is there a way to compile perl to binary exe. [In reply to] Can't Post
Thank you for that advice, I will test it soon.
Thanks again,
Brian Hayes
freelancer
Deleted
Nov 15, 2000, 1:18 PM
Post #15 of 15 (1786 views)
Re: is there a way to compile perl to binary exe. [In reply to] Can't Post
How can I decompile an .exe file made by Perl2exe into a .pl file?
Announcements PerlGuru Announcements Perl Programming Help Frequently Asked Questions Beginner Intermediate Advanced Regular Expressions mod_perl DBI Win32 Programming Help Fun With Perl Perl Quizzes - Learn Perl the Fun Way Perl Golf Perl Poetry Need a Custom or Prewritten Perl Program? I need a program that... I Need a Programmer for Freelance Work Throw Down The Gauntlet General Discussions General Questions Feedback Tutorial/Article Suggestions for The Learning Cent Internet Security Other Programming Languages Javascript PHP
Search this forum this category all forums for All words Any words Whole Phrase (options) Powered by Gossamer Forum v.1.2.0 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8886100053787231, "perplexity": 7962.798172155022}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-26/segments/1466783397748.48/warc/CC-MAIN-20160624154957-00108-ip-10-164-35-72.ec2.internal.warc.gz"} |
https://jp.maplesoft.com/support/help/addons/view.aspx?path=liesymm | Overview - Maple Help
Overview of the liesymm Package
Description
• Each command in the liesymm package can be accessed by using either the long form or the short form of the command name in the command calling sequence.
• This is an implementation of the Harrison-Estabrook procedure (see References section). It obtains the determining equations leading to the similarity solutions of a system of partial differential equations using a number of important refinements and extensions as developed by J. Carminati.
• To construct the determining equations for the isovector using Cartan's geometric formulation of partial differential equations in terms of differential ideals use determine(). Other commands help to convert the set of equations to an equivalent set of differential forms or vice versa.
• You can compute or check for closure of a given set of forms and annul to a specified sublist of independent coordinates. Modding lists are used to eliminate those parts of a differential form belonging to the ideal.
• The implementation makes use of the exterior derivative (d) and wedge product (&^) but is completely independent of the Maple difforms package. It requires a specific coordinate system as defined by setup(). Unknowns default to constants, and automatic simplifications take into account a consistent ordering of the 1-forms and the extraction of coefficients.
List of liesymm Package Commands
• The following is a list of available commands.
To display the help page for a particular liesymm command, see Getting Help with a Command in a Package.
• A brief description of the functionality available follows.
setup to define (or redefine) a list of coordinate variables (0-forms). d to compute the exterior derivative with respect to the specified coordinates. &^ to compute the wedge product. It automatically simplifies relative to an "address" ordering of the basis variables to sums of expressions of the form c*(d(x)&^d(y)&^d(z)). Lie to compute the Lie derivative of an expression involving forms, relative to a specified vector. wcollect to express a form as a sum of forms each multiplied by a coefficient of wedge degree 0. wsubs to substitute an expression for a $k$-form that is part of an $n$-form.
• Various other commands such as choose, getcoeff, mixpar, wdegree, wedgeset, and value are used in manipulating the forms and results.
• Let eqn be a set or list of partial differential equations involving functions,
$\mathrm{flist}=\left[\mathrm{f1},\mathrm{f2},\mathrm{...},\mathrm{fn}\right]\left(\mathrm{x1},\mathrm{...},\mathrm{xj}\right)$
convert(eqlist, forms, eqlist, w) Generates a set of forms that or when closed characterize the equations makeforms(eqns, flist, w) in eqlist in the sense of Cartan. convert(forms, system, vlist) Generates a set of partial differential or equations represented by the given annul(forms, vlist) forms. close(forms) Extends the given list of forms to achieve closure under application of d(). hasclosure(forms) Checks if the forms list is closed under applications of d() &mod Reduces a form modulo an exterior ideal (specified by a closed list of forms). determine(forms, V) Given a list of forms describing a particular set of partial differential equations with coordinates the calling sequence produces a set of first order equations for the isovector vector (V1, ..., Vn). The resulting equations are expressed using alias and an inert Diff rather than diff but evaluation can be forced by using value(). determine(f, V, h(t, x), w) As above, but with f as an equation and with the extra arguments used by makeforms() to construct the initial forms list.
• You need not work with the differential forms directly. When given a list of partial differential equations instead of a forms list, the command determine() sets up the coordinates and differential forms as required.
• Partial derivatives should be expressed in terms of Diff() rather than diff() or D(). The command mixpar() may be used to force mixed partials to a consistent ordering.
• Use value() to convert Diff() to diff() when interpreting or using the result of determine.
Examples
Nonlinear Boltzmann's equation.
> $\mathrm{with}\left(\mathrm{liesymm}\right):$
> $\mathrm{setup}\left(\right)$
$\left[\right]$ (1)
> $\mathrm{eq}≔\mathrm{Diff}\left(u\left(x,t\right),x,t\right)+\mathrm{Diff}\left(u\left(x,t\right),x\right)+{u\left(x,t\right)}^{2}=0$
${\mathrm{eq}}{≔}\frac{{{\partial }}^{{2}}}{{\partial }{x}{\partial }{t}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{u}{}\left({x}{,}{t}\right){+}\frac{{\partial }}{{\partial }{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{u}{}\left({x}{,}{t}\right){+}{{u}{}\left({x}{,}{t}\right)}^{{2}}{=}{0}$ (2)
> $\mathrm{forms}≔\mathrm{makeforms}\left(\mathrm{eq},u\left(x,t\right),w\right)$
${\mathrm{forms}}{≔}\left[{d}{}\left({u}\right){-}{\mathrm{w1}}{}{d}{}\left({x}\right){-}{\mathrm{w2}}{}{d}{}\left({t}\right){,}{d}{}\left({\mathrm{w2}}\right)\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}{&ˆ}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}{d}{}\left({t}\right){+}\left({{u}}^{{2}}{+}{\mathrm{w1}}\right){}{d}{}\left({x}\right)\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}{&ˆ}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}{d}{}\left({t}\right)\right]$ (3)
> $\mathrm{eq}≔\mathrm{mixpar}\left(\mathrm{eq}\right)$
${\mathrm{eq}}{≔}\frac{{{\partial }}^{{2}}}{{\partial }{t}{\partial }{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{u}{}\left({x}{,}{t}\right){+}\frac{{\partial }}{{\partial }{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{u}{}\left({x}{,}{t}\right){+}{{u}{}\left({x}{,}{t}\right)}^{{2}}{=}{0}$ (4)
> $\mathrm{determine}\left(\mathrm{eq},V,u\left(x,t\right),w\right)$
$\left\{\frac{{{\partial }}^{{2}}}{{\partial }{t}{\partial }{u}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V1}}{}\left({x}{,}{t}{,}{u}\right){=}{0}{,}\frac{{{\partial }}^{{2}}}{{\partial }{t}{\partial }{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V1}}{}\left({x}{,}{t}{,}{u}\right){=}\frac{{{\partial }}^{{2}}}{{\partial }{t}{\partial }{u}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V3}}{}\left({x}{,}{t}{,}{u}\right){+}\frac{{\partial }}{{\partial }{t}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V2}}{}\left({x}{,}{t}{,}{u}\right){,}\frac{{{\partial }}^{{2}}}{{\partial }{{u}}^{{2}}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V1}}{}\left({x}{,}{t}{,}{u}\right){=}{0}{,}\frac{{{\partial }}^{{2}}}{{\partial }{u}{\partial }{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V1}}{}\left({x}{,}{t}{,}{u}\right){=}\frac{{{\partial }}^{{2}}}{{\partial }{{u}}^{{2}}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V3}}{}\left({x}{,}{t}{,}{u}\right){-}\frac{{{\partial }}^{{2}}}{{\partial }{t}{\partial }{u}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V2}}{}\left({x}{,}{t}{,}{u}\right){,}\frac{{{\partial }}^{{2}}}{{\partial }{t}{\partial }{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V2}}{}\left({x}{,}{t}{,}{u}\right){=}\frac{{{\partial }}^{{2}}}{{\partial }{u}{\partial }{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V3}}{}\left({x}{,}{t}{,}{u}\right){,}\frac{{{\partial }}^{{2}}}{{\partial }{{u}}^{{2}}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V2}}{}\left({x}{,}{t}{,}{u}\right){=}{0}{,}\frac{{{\partial }}^{{2}}}{{\partial }{u}{\partial }{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V2}}{}\left({x}{,}{t}{,}{u}\right){=}{0}{,}\frac{{{\partial }}^{{2}}}{{\partial }{t}{\partial }{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V3}}{}\left({x}{,}{t}{,}{u}\right){=}\frac{{\partial }}{{\partial }{u}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V3}}{}\left({x}{,}{t}{,}{u}\right){}{{u}}^{{2}}{-}\frac{{\partial }}{{\partial }{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V1}}{}\left({x}{,}{t}{,}{u}\right){}{{u}}^{{2}}{-}\frac{{\partial }}{{\partial }{t}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V2}}{}\left({x}{,}{t}{,}{u}\right){}{{u}}^{{2}}{-}{2}{}{\mathrm{V3}}{}\left({x}{,}{t}{,}{u}\right){}{u}{-}\frac{{\partial }}{{\partial }{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V3}}{}\left({x}{,}{t}{,}{u}\right){,}\frac{{\partial }}{{\partial }{t}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V1}}{}\left({x}{,}{t}{,}{u}\right){=}{0}{,}\frac{{\partial }}{{\partial }{u}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V1}}{}\left({x}{,}{t}{,}{u}\right){=}{0}{,}\frac{{\partial }}{{\partial }{u}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V2}}{}\left({x}{,}{t}{,}{u}\right){=}{0}{,}\frac{{\partial }}{{\partial }{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{V2}}{}\left({x}{,}{t}{,}{u}\right){=}{0}\right\}$ (5)
> $\mathrm{value}\left(\right):$
> $\mathrm{wedgeset}\left(0\right)$
${x}{,}{t}{,}{u}{,}{\mathrm{w1}}{,}{\mathrm{w2}}$ (6)
> $\mathrm{close}\left(\mathrm{forms}\right)$
$\left[{d}{}\left({u}\right){-}{\mathrm{w1}}{}{d}{}\left({x}\right){-}{\mathrm{w2}}{}{d}{}\left({t}\right){,}{d}{}\left({\mathrm{w2}}\right)\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}{&ˆ}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}{d}{}\left({t}\right){+}\left({{u}}^{{2}}{+}{\mathrm{w1}}\right){}{d}{}\left({x}\right)\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}{&ˆ}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}{d}{}\left({t}\right){,}{-}{d}{}\left({\mathrm{w1}}\right)\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}{&ˆ}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}{d}{}\left({x}\right){-}{d}{}\left({\mathrm{w2}}\right)\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}{&ˆ}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}{d}{}\left({t}\right)\right]$ (7)
> $\mathrm{annul}\left(,\left[x,t\right]\right)$
$\left[\frac{{\partial }}{{\partial }{t}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{u}{}\left({x}{,}{t}\right){-}{\mathrm{w2}}{}\left({x}{,}{t}\right){=}{0}{,}\frac{{\partial }}{{\partial }{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{u}{}\left({x}{,}{t}\right){-}{\mathrm{w1}}{}\left({x}{,}{t}\right){=}{0}{,}{{u}{}\left({x}{,}{t}\right)}^{{2}}{+}\frac{{\partial }}{{\partial }{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{w2}}{}\left({x}{,}{t}\right){+}{\mathrm{w1}}{}\left({x}{,}{t}\right){=}{0}{,}\frac{{\partial }}{{\partial }{t}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{w1}}{}\left({x}{,}{t}\right){-}\frac{{\partial }}{{\partial }{x}}\phantom{\rule[-0.0ex]{0.4em}{0.0ex}}{\mathrm{w2}}{}\left({x}{,}{t}\right){=}{0}\right]$ (8)
References
"Harrison-Estabrook procedure." Journal of Mathematical Physics , Vol. 12. New York: American Institute of Physics. (1971): 653-665. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 21, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9645710587501526, "perplexity": 1175.370824514038}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764500904.44/warc/CC-MAIN-20230208191211-20230208221211-00613.warc.gz"} |
https://stats.stackexchange.com/questions/64612/how-do-you-interpret-results-from-unit-root-tests-with-intercept | # How do you interpret results from unit root tests with intercept?
Null Hypothesis: LOG_AUSTRIA has a unit root
Exogenous: Constant
Lag Length: 1 (Automatic - based on SIC, maxlag=29)
t-Statistic Prob.*
Augmented Dickey-Fuller test statistic 1.765602 0.9997
Test critical values: 1% level -3.432059
5% level -2.862181
10% level -2.567155
*MacKinnon (1996) one-sided p-values.
Augmented Dickey-Fuller Test Equation
Dependent Variable: D(LOG_AUSTRIA)
Method: Least Squares
Date: 07/17/13 Time: 18:55
Variable Coefficient Std. Error t-Statistic Prob.
LOG_AUSTRIA(-1) 0.000659 0.000373 1.765602 0.0776
D(LOG_AUSTRIA(-1)) 0.053321 0.017030 3.131112 0.0018
C -0.003183 0.002040 -1.560515 0.1187
R-squared 0.003923 Mean dependent var 0.000428
Adjusted R-squared 0.003345 S.D. dependent var 0.010612
S.E. of regression 0.010595 Akaike info criterion -6.256058
Sum squared resid 0.386693 Schwarz criterion -6.250711
Log likelihood 10788.44 Hannan-Quinn criter. -6.254148
F-statistic 6.784764 Durbin-Watson stat 2.000233
Prob(F-statistic) 0.001146
• Welcome to the site, @user28136. I recognize that your title is informative, but it might be nice to add some context to your question in the body, rather than just paste output. What is it that's confusing you exactly? – gung Jul 17 '13 at 16:23
• I have not expirience from Eviews programm.I want the interpretation particularly the t-statistic and Prob for my example (Log_austria) – user28136 Jul 17 '13 at 16:30
For the interpretation of Eviews output, just focus on top part. The lower one shows how the Eviews runs the regression. Eviews runs the regression in first difference form, so the null is coefficient on LOG_AUSTRIA(-1) is zero which means that there is an unit root.The alternate hypothesis is that it is less than zero, i.e., there is no unit root.
Your test statistic 1.765602 is greater than critical value -2.567155 at 10%. So, you accept the null that there is an unit root (see p=0.999). To reject the null at 10 %, p<=0.10 (test statistic should be less than -2.567155), to reject the null at 5% (test statistic should be less than-2.862181) p<=0.05, and to reject the null at 1%,(test statistic should be less than-3.432059) p<=0.01.
• thank you so much,your answer helps me to organize my results.And something else i always put absolute value in t-statistic to compare or not? – user28136 Jul 18 '13 at 12:11
• this is one tailed test and so you can't use the absolute value for comparison. Also, note that you are comparing your calculated t-statistics with tabulated tau (and not t) statistics. Please check the answer as correct so that it will be helpful for future Eviews user like you. – Metrics Jul 18 '13 at 13:30
• This might be also helpful for you. – Metrics Jul 18 '13 at 13:32
I am not sure if this is what you are asking, but one might conceive of an integrated process that looks something like this:
$$y_{t} = y_{t-1} + \varepsilon$$
Feel free to define the distribution of $\varepsilon$ according to your needs and whimsy, and you have got yourself a nice little nonstationary random walk process.
The "unit root" in the above case is in the invisible coefficient $\beta_{y_{t-1}}$, which equals $1$ or $-1$ ($|1|$ being the "unit" in the unit root). I think you may be asking about the intercept in a model like this:
$$y_{t} = \beta_{0} + y_{t-1} + \varepsilon$$
This model is very similar to the above, except for every unit of time, the time series changes by $\beta_{0}$. If you were to eliminate the random portion of this process, what you would be left with is a linear change in $y$ over unit time. So $\beta_{0}$ is the slope of a linear trend over time in a unit root process added to the nice random walk in the remaining portion of the model.
Of course, $\beta_{y_{t-1}}$ need not be invisible, and may be estimated from data, and may not equal exactly $1$ or $-1$. When $|\beta_{y_{t-1}}| < 1$, then one's time series is not technically "integrated," but rather has a long memory, or is near integrated (if the value is close to $1$ or $-1$). If $|\beta_{y_{t-1}}| > 1$, then your time series diverges/explodes. The linear trend implied by $\beta_{0}$ remains just that in such cases.
## protected by whuber♦Mar 22 '16 at 15:28
Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count). | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8229402899742126, "perplexity": 1266.1734300291512}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-43/segments/1570986688826.38/warc/CC-MAIN-20191019040458-20191019063958-00058.warc.gz"} |
http://arxiv-export-lb.library.cornell.edu/abs/2108.03002 | math.NA
(what is this?)
Title: Two New Low Rank Tensor Completion Methods Based on Sum Nuclear Norm
Abstract: The low rank tensor completion (LRTC) problem has attracted great attention in computer vision and signal processing. How to acquire high quality image recovery effect is still an urgent task to be solved at present. This paper proposes a new tensor $L_{2,1}$ norm minimization model (TLNM) that integrates sum nuclear norm (SNN) method, differing from the classical tensor nuclear norm (TNN)-based tensor completion method, with $L_{2,1}$ norm and Qatar Riyal decomposition for solving the LRTC problem. To improve the utilization rate of the local prior information of the image, a total variation (TV) regularization term is introduced, resulting in a new class of tensor $L_{2,1}$ norm minimization with total variation model (TLNMTV). Both proposed models are convex and therefore have global optimal solutions. Moreover, we adopt the Alternating Direction Multiplier Method (ADMM) to obtain the closed-form solution of each variable, thus ensuring the feasibility of the algorithm. Numerical experiments show that the two proposed algorithms are convergent and outperform compared methods. In particular, our method significantly outperforms the contrastive methods when the sampling rate of hyperspectral images is 2.5\%.
Subjects: Numerical Analysis (math.NA); Computer Vision and Pattern Recognition (cs.CV); Machine Learning (cs.LG) Cite as: arXiv:2108.03002 [math.NA] (or arXiv:2108.03002v4 [math.NA] for this version)
Submission history
From: HongBing Zhang [view email]
[v1] Fri, 6 Aug 2021 08:35:33 GMT (50549kb,D)
[v2] Thu, 12 Aug 2021 10:45:32 GMT (50551kb,D)
[v3] Sat, 14 Aug 2021 09:07:57 GMT (50543kb,D)
[v4] Mon, 11 Jul 2022 08:18:06 GMT (31439kb,D)
Link back to: arXiv, form interface, contact. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9325879216194153, "perplexity": 2211.319321726221}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030337480.10/warc/CC-MAIN-20221004054641-20221004084641-00267.warc.gz"} |
https://runestone.academy/runestone/static/pythonds/BasicDS/Lists.html | # 3.19. Lists¶
Throughout the discussion of basic data structures, we have used Python lists to implement the abstract data types presented. The list is a powerful, yet simple, collection mechanism that provides the programmer with a wide variety of operations. However, not all programming languages include a list collection. In these cases, the notion of a list must be implemented by the programmer.
A list is a collection of items where each item holds a relative position with respect to the others. More specifically, we will refer to this type of list as an unordered list. We can consider the list as having a first item, a second item, a third item, and so on. We can also refer to the beginning of the list (the first item) or the end of the list (the last item). For simplicity we will assume that lists cannot contain duplicate items.
For example, the collection of integers 54, 26, 93, 17, 77, and 31 might represent a simple unordered list of exam scores. Note that we have written them as comma-delimited values, a common way of showing the list structure. Of course, Python would show this list as $$[54,26,93,17,77,31]$$.
Next Section - 3.20. The Unordered List Abstract Data Type | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.37628310918807983, "perplexity": 348.81561997321904}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-51/segments/1512948515165.6/warc/CC-MAIN-20171212041010-20171212061010-00243.warc.gz"} |
http://tex.stackexchange.com/questions/95247/how-to-draw-a-mexican-hat-potential-using-3dplot | # How to draw a “Mexican hat potential” using 3dplot?
I would like to make a Mexican hat potential (like this one from Wikipedia)
drawing through TikZ, and I am sure the function to use is straightforward, but I have not managed to find the right solution myself... !
I am using this as a starting point, just need the right function...
\tdplotsetmaincoords{70}{135}
\tdplotsetpolarplotrange{90}{180}{0}{360}
\begin{tikzpicture}[line join=bevel,tdplot_main_coords, fill opacity=.7]
\tdplotsphericalsurfaceplot[parametricfill]{72}{36}%
{4}{black}{\tdplottheta}%
{\draw[color=black,thick,->] (0,0,0) -- (20,0,0) node[anchor=north east]{$x$};}%
{\draw[color=black,thick,->] (0,0,0) -- (0,20,0) node[anchor=north west]{$y$};}%
{\draw[color=black,thick,->] (0,0,0) -- (0,0,3) node[anchor=south]{$z$};}%
\end{tikzpicture}
Any hints will be gratefully appreciated!!
Thanks again!
I now have a little problem getting the axis right. I want them placed in the middle of the plot, but I cannot seem to get the labels correct? Also, I would like to rotate the axis so that the x,y arrows point towards us, and the z up as it is now. Any tips? This is what I have now:
\pgfplotsset{
standard/.style={
axis x line=middle,
axis y line=middle,
axis z line=middle,
enlarge x limits=0.15,
enlarge y limits=0.15,
enlarge x limits=0.15,
every axis x label/.style={at={(current axis.right of origin)},anchor=north west},
every axis y label/.style={at={(current axis.above origin)},anchor=north east},
every axis z label/.style={at={(current axis.above origin)},anchor=south}
}
}
\begin{tikzpicture}
\begin{axis}[
standard,
colormap={blackwhite}{gray(0cm)=(1); gray(1cm)=(0)},
samples=30,
domain=0:360,
y domain=0:1.25,
zmin=0,
zmax=2,
xlabel=$\mathcal{RE}\,(\phi)$,
ylabel=$\mathcal{IM}\,(\phi)$,
zlabel=$V$,
yticklabels={,,},
xticklabels={,,},
zticklabels={,,}
]
\end{axis}
\end{tikzpicture}
It produces the following figure:
But as you see the axis labelling is not optimal, and the axis is rotated the wrong direction..
Thanks so much so far!
-
Related: Mexican hat in TikZ. – Peter Grill Jan 24 '13 at 20:48
PGFPlots can plot 3D parametric functions. Here's the output using the function that is used for the Wikipedia image:
\documentclass[border=5mm]{standalone}
\usepackage{pgfplots}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
hide axis,
samples=30,
domain=0:360,
y domain=0:1.25
]
Awesome, Jake! :) Soundtrack while running this example. :) – Paulo Cereda Jan 24 '13 at 20:57 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7971432209014893, "perplexity": 2701.937008054197}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-41/segments/1410657136963.94/warc/CC-MAIN-20140914011216-00019-ip-10-234-18-248.ec2.internal.warc.gz"} |
http://www.encyclopediaofmath.org/index.php/Pontryagin_square | # Pontryagin square
A cohomology operation of type , i.e. a functorial mapping
defined for any pair of topological spaces and such that for any continuous mapping the equality (naturality) holds.
Pontryagin squares have the following properties:
1) , where is the natural imbedding.
2) and , where is the quotient homomorphism modulo .
3) , where is the suspension mapping and is the Postnikov square (in other words, the cohomology suspension of is ). If
and
are the representing mappings, then .
The properties 1), 2) uniquely characterize the Pontryagin square and thus can be taken as an axiomatic definition of it. Constructively the Pontryagin square is defined by the formula
where is a cocycle modulo (for the -products see Steenrod square).
There exists (see [5], [6]) a generalization of the Pontryagin square to the case when is an arbitrary odd prime number. This generalization is a cohomology operation of type and is called the -th Pontryagin power . The operation is uniquely defined by the following formulas:
where is the natural imbedding; and
where is the quotient homomorphism modulo generalizing the corresponding formulas for . The analogue of formula 3) for has the form , which means that the cohomology suspension of for is zero. For the equality holds, the multiplication may be taken both as outer (-multiplication) or inner (-multiplication). For the corresponding equality is valid only up to summands of order 2.
In the most general way the Pontryagin square is defined for cohomology with coefficients in an arbitrary finitely-generated Abelian group (see [2], [3]). In final form this generalization is as follows (see [6]). The Pontryagin square is a ring homomorphism
where is a functor which associates a ring with divided powers to an Abelian group. For , the -th component of this homomorphism coincides with the -th Pontryagin power (for with the Pontryagin square ).
#### References
[1] L.S. Pontryagin, "Mappings of a 3-dimensional sphere into an -dimensional complex" Dokl. Akad. Nauk SSSR , 34 (1942) pp. 35–37 (In Russian) [2] V.G. Boltyanskii, "The homotopy theory of continuous mapping and vector fields" , Moscow (1955) (In Russian) [3] M.M. Postnikov, "The classification of continuous mappings of a three-dimensional polyhedron into a simply connected polyhedron of arbitrary dimension" Dokl. Akad. Nauk SSSR , 64 : 4 (1949) pp. 461–462 (In Russian) [4] W. Browder, E. Thomas, "Axioms for the generalized Pontryagin cohomology operations" Quart. J. Math. , 13 (1962) pp. 55–60 [5] E. Thomas, "A generalization of the Pontrjagin square cohomology operation" Proc. Nat. Acad. Sci. USA , 42 (1956) pp. 266–269 [6] E. Thomas, "The generalized Pontryagin cohomology operations and rings with divided powers" , Amer. Math. Soc. (1957) | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.995168149471283, "perplexity": 817.8896011491189}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368703293367/warc/CC-MAIN-20130516112133-00060-ip-10-60-113-184.ec2.internal.warc.gz"} |
https://homework.cpm.org/category/ACC/textbook/acc6/chapter/5%20Unit%205/lesson/CC1:%205.1.4/problem/5-37 | ### Home > ACC6 > Chapter 5 Unit 5 > Lesson CC1: 5.1.4 > Problem5-37
5-37.
Richard’s strategy for changing a percent to a decimal is to put the decimal point in front of the percent number. An example of his work is shown at right. Do you agree with Richard’s method? Explain your reasoning.
$8\%=0.8$ $80\%=0.80$ $800\%=0.800$
Should $8\%$, $80\%$, and $800\%$ all be represented as equivalent decimals?
If not, there is a flaw with Richard's strategy.
No, because converting from a percent to a decimal involves dividing by $100$ or shifting the decimal place to the left twice. | {"extraction_info": {"found_math": true, "script_math_tex": 7, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8446779251098633, "perplexity": 1201.186390453614}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-34/segments/1596439738723.55/warc/CC-MAIN-20200810235513-20200811025513-00352.warc.gz"} |
http://xn--bta-yla.net/index.html | # content
## Index
I am a British security researcher, currently a PhD student and RA at Lancaster University. My area is what has sometimes been called 'security informatics' -- essentially, data science as applied to privacy and security problems. I mostly work with open data. I have worked on projects tackling the distribution of child abuse material, problems in online identity resolution and most recently I am working on the DAPM project, developing methods to detect and prevent mass-market fraud campaigns.
Those wishing to see some of my academic or programming output, such as it is, can find it on the projects page.
I keep a record of books I have read under book reviews.
Those strange few looking for some personal commentary can find it under notes.
Despite having studied social media academically, I don't use very much of it myself. I use a pseudonym, but my identity is trivially resolvable -- it's more of a pen-name.
I am Betawolf in #lesswrong on Freenode | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.154782235622406, "perplexity": 2540.9824080392427}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-13/segments/1521257645538.8/warc/CC-MAIN-20180318052202-20180318072202-00094.warc.gz"} |
http://jonathanweisberg.org/post/A%20Neural%20Network%20from%20Scratch%20-%20Part%201/ | # Building a Neural Network from Scratch: Part 1
In this post we’re going to build a neural network from scratch. We’ll train it to recognize hand-written digits, using the famous MNIST data set.
We’ll use just basic Python with NumPy to build our network (no high-level stuff like Keras or TensorFlow). We will dip into scikit-learn, but only to get the MNIST data and to assess our model once its built.
We’ll start with the simplest possible “network”: a single node that recognizes just the digit 0. This is actually just an implementation of logistic regression, which may seem kind of silly. But it’ll help us get some key components working before things get more complicated.
Then we’ll extend that into a network with one hidden layer, still recognizing just 0. Then we’ll add a softmax for recognizing all the digits 0 through 9. That’ll give us a 92% accurate digit-recognizer, bringing us up to the cutting edge of 1985 technology.
In a followup post we’ll bring that up into the high nineties by making sundry improvements: better optimization, more hidden layers, and smarter initialization.
# 1. Hello, MNIST
MNIST contains 70,000 images of hand-written digits, each 28 x 28 pixels, in greyscale with pixel-values from 0 to 255. We could download and preprocess the data ourselves. But the makers of scikit-learn already did that for us. Since it would be rude to neglect their efforts, we’ll just import it:
from sklearn.datasets import fetch_mldata
mnist = fetch_mldata('MNIST original')
X, y = mnist["data"], mnist["target"]
We’ll normalize the data to keep our gradients manageable:
X = X / 255
The default MNIST labels record 7 for an image of a seven, 4 for an image of a four, etc. But we’re just building a zero-classifier for now. So we want our labels to say 1 when we have a zero, and 0 otherwise (intuitive, I know). So we’ll overwrite the labels to make that happen:
import numpy as np
y_new = np.zeros(y.shape)
y_new[np.where(y == 0.0)[0]] = 1
y = y_new
Now we can make our train/test split. The MNIST images are pre-arranged so that the first 60,000 can be used for training, and the last 10,000 for testing. We’ll also transform the data into the shape we want, with each example in a column (instead of a row):
m = 60000
m_test = X.shape[0] - m
X_train, X_test = X[:m].T, X[m:].T
y_train, y_test = y[:m].reshape(1,m), y[m:].reshape(1,m_test)
Finally we’ll shuffle the training set for good measure:
np.random.seed(138)
shuffle_index = np.random.permutation(m)
X_train, y_train = X_train[:,shuffle_index], y_train[:,shuffle_index]
Let’s have a look at a random image and label just to make sure we didn’t throw anything out of wack:
%matplotlib inline
import matplotlib
import matplotlib.pyplot as plt
i = 3
plt.imshow(X_train[:,i].reshape(28,28), cmap = matplotlib.cm.binary)
plt.axis("off")
plt.show()
print(y_train[:,i])
[1.]
That’s a zero, so we want the label to be 1, which it is. Looks good, so let’s build our first network.
# 2. A Single Neuron (aka Logistic Regression)
We want to build a simple, feed-forward network with 784 inputs (=28 x 28), and a single sigmoid unit generating the output.
## 2.1 Forward Propogation
The forward pass on a single example $x$ executes the following computation: $$\hat{y} = \sigma(w^T x + b).$$ Here $\sigma$ is the sigmoid function: $$\sigma(z) = \frac{1}{1 + e^{-z}}.$$ So let’s define:
def sigmoid(z):
s = 1 / (1 + np.exp(-z))
return s
We’ll vectorize by stacking examples side-by-side, so that our input matrix $X$ has an example in each column. The vectorized form of the forward pass is then: $$\hat{y} = \sigma(w^T X + b).$$ Note that $\hat{y}$ is now a vector, not a scalar as it was in the previous equation.
In our code we’ll compute this in two stages: Z = np.matmul(W.T, X) + b and then A = sigmoid(Z). (A for Activation.) Breaking things up into stages like this is just for tidiness—it’ll make our forward propagation computations mirror the steps in our backward propagation computations.
## 2.2 Cost Function
We’ll use cross-entropy for our cost function. The formula for a single training example is: $$L(y, \hat{y}) = -y \log(\hat{y}) - (1-y) \log(1-\hat{y}).$$ Averaging over a training set of $m$ examples we then have: $$L(Y, \hat{Y}) = -\frac{1}{m} \sum_{i=1}^m \left( y^{(i)} \log(\hat{y}^{(i)}) + (1-y^{(i)}) \log(1-\hat{y}^{(i)}) \right).$$ So let’s define:
def compute_loss(Y, Y_hat):
m = Y.shape[1]
L = -(1./m) * ( np.sum( np.multiply(np.log(Y_hat),Y) ) + np.sum( np.multiply(np.log(1-Y_hat),(1-Y)) ) )
return L
## 2.3 Backward Propagation
For backpropagation, we’ll need to know how $L$ changes with respect to each component $w_j$ of $w$. That is, we must compute each $\partial L / \partial w_j$.
Focusing on a single example will make it easier to derive the formulas we need. Holding all values except $w_j$ fixed, we can think of $L$ as being computed in three steps: $w_j \rightarrow z \rightarrow \hat{y} \rightarrow L$. The formulas for these steps are: \begin{align} z &= w^T x + b,\newline \hat{y} &= \sigma(z),\newline L(y, \hat{y}) &= -y \log(\hat{y}) - (1-y) \log(1-\hat{y}). \end{align} And the chain rule tells us: $$\frac{\partial L}{\partial w_j} = \frac{\partial L}{\partial \hat{y}} \frac{\partial \hat{y}}{\partial z} \frac{\partial z}{\partial w_j}.$$ Looking at $\partial L / \partial \hat{y}$ first: \begin{align} \frac{\partial L}{\partial \hat{y}} &= \frac{\partial}{\partial \hat{y}} \left( -y \log(\hat{y}) - (1-y) \log(1-\hat{y}) \right)\newline &= -y \frac{\partial}{\partial \hat{y}} \log(\hat{y}) - (1-y) \frac{\partial}{\partial \hat{y}} \log(1-\hat{y})\newline &= \frac{-y}{\hat{y}} + \frac{(1-y) }{1 - \hat{y}}\newline &= \frac{\hat{y} - y}{\hat{y}(1 - \hat{y})}. \end{align} Next we want $\partial \hat{y} / \partial z$: \begin{align} \frac{\partial}{\partial z} \sigma(z) &= \frac{\partial}{\partial z} \left( \frac{1}{1 + e^{-z}} \right)\newline &= - \frac{1}{(1 + e^{-z})^2} \frac{\partial}{\partial z} \left( 1 + e^{-z} \right)\newline &= \frac{e^{-z}}{(1 + e^{-z})^2}\newline &= \frac{1}{1 + e^{-z}} \frac{e^{-z}}{1 + e^{-z}}\newline &= \sigma(z) \frac{e^{-z}}{1 + e^{-z}}\newline &= \sigma(z) \left( 1 - \frac{1}{1 + e^{-z}} \right)\newline &= \sigma(z) \left( 1 - \sigma(z) \right)\newline &= \hat{y} (1-\hat{y}). \end{align} Lastly we tackle $\partial z / \partial w_j$: \begin{align} \frac{\partial}{\partial w_j} (w^T x + b) &= \frac{\partial}{\partial w_j} (w_0 x_0 + \ldots + w_n x_n + b)\newline &= w_j. \end{align} Finally we can substitute into the chain rule to find: \begin{align} \frac{\partial L}{\partial w_j} &= \frac{\partial L}{\partial \hat{y}} \frac{\partial \hat{y}}{\partial z} \frac{\partial z}{\partial w_j}\newline &= \frac{\hat{y} - y}{\hat{y}(1 - \hat{y})} \hat{y} (1-\hat{y}) w_j\newline &= (\hat{y} - y) w_j.\newline \end{align} In vectorized form with $m$ training examples this gives us: $$\frac{\partial L}{\partial w} = \frac{1}{m} X (\hat{y} - y)^T.$$ What about $\partial L / \partial b$? A very similar derivation yields, for a single example: \begin{align} \frac{\partial L}{\partial b} &= (\hat{y} - y). \end{align} Which in vectorized form amounts to: $$\frac{\partial L}{\partial b} = \frac{1}{m} \sum_{i=1}^m (\hat{y}^{(i)} - y^{(i)}).$$ In our code we’ll label these gradients according to their denominators, as dW and db. So for backpropagation we’ll compute dW = (1/m) * np.matmul(X, (A-Y).T) and db = (1/m) * np.sum(A-Y, axis=1, keepdims=True).
## 2.4 Build & Train
Ok we’re ready to build and train our network!
learning_rate = 1
X = X_train
Y = y_train
n_x = X.shape[0]
m = X.shape[1]
W = np.random.randn(n_x, 1) * 0.01
b = np.zeros((1, 1))
for i in range(2000):
Z = np.matmul(W.T, X) + b
A = sigmoid(Z)
cost = compute_loss(Y, A)
dW = (1/m) * np.matmul(X, (A-Y).T)
db = (1/m) * np.sum(A-Y, axis=1, keepdims=True)
W = W - learning_rate * dW
b = b - learning_rate * db
if (i % 100 == 0):
print("Epoch", i, "cost: ", cost)
print("Final cost:", cost)
Epoch 0 cost: 0.6840801595436431
Epoch 100 cost: 0.041305162058342754
... *snip* ...
Final cost: 0.02514156608481825
We could probably eek out a bit more accuracy with some more training. But the gains have slowed considerably. So let’s just see how we did, by looking at the confusion matrix:
from sklearn.metrics import classification_report, confusion_matrix
Z = np.matmul(W.T, X_test) + b
A = sigmoid(Z)
predictions = (A>.5)[0,:]
labels = (y_test == 1)[0,:]
print(confusion_matrix(predictions, labels))
[[8980 33]
[ 40 947]]
Hey, that’s actually pretty good! We got 947 of the zeros and missed only 33, while getting nearly all the negative cases right. In terms of f1-score that’s 0.99:
print(classification_report(predictions, labels))
precision recall f1-score support
False 1.00 1.00 1.00 9013
True 0.97 0.96 0.96 987
avg / total 0.99 0.99 0.99 10000
So, now that we’ve got a working model and optimization algorithm, let’s enrich it.
# 3. One Hidden Layer
Let’s add a hidden layer now, with 64 units (a mostly arbitrary choice). I won’t go through the derivations of all the formulas for the forward and backward passes this time; they’re a pretty direct extension of the work we did earlier. Instead let’s just dive right in and build the model:
X = X_train
Y = y_train
n_x = X.shape[0]
n_h = 64
learning_rate = 1
W1 = np.random.randn(n_h, n_x)
b1 = np.zeros((n_h, 1))
W2 = np.random.randn(1, n_h)
b2 = np.zeros((1, 1))
for i in range(2000):
Z1 = np.matmul(W1, X) + b1
A1 = sigmoid(Z1)
Z2 = np.matmul(W2, A1) + b2
A2 = sigmoid(Z2)
cost = compute_loss(Y, A2)
dZ2 = A2-Y
dW2 = (1./m) * np.matmul(dZ2, A1.T)
db2 = (1./m) * np.sum(dZ2, axis=1, keepdims=True)
dA1 = np.matmul(W2.T, dZ2)
dZ1 = dA1 * sigmoid(Z1) * (1 - sigmoid(Z1))
dW1 = (1./m) * np.matmul(dZ1, X.T)
db1 = (1./m) * np.sum(dZ1, axis=1, keepdims=True)
W2 = W2 - learning_rate * dW2
b2 = b2 - learning_rate * db2
W1 = W1 - learning_rate * dW1
b1 = b1 - learning_rate * db1
if i % 100 == 0:
print("Epoch", i, "cost: ", cost)
print("Final cost:", cost)
Epoch 0 cost: 0.9144384083567224
Epoch 100 cost: 0.08856953026938433
... *snip* ...
Final cost: 0.024249298861903648
How’d we do?
Z1 = np.matmul(W1, X_test) + b1
A1 = sigmoid(Z1)
Z2 = np.matmul(W2, A1) + b2
A2 = sigmoid(Z2)
predictions = (A2>.5)[0,:]
labels = (y_test == 1)[0,:]
print(confusion_matrix(predictions, labels))
print(classification_report(predictions, labels))
[[8984 36]
[ 36 944]]
precision recall f1-score support
False 1.00 1.00 1.00 9020
True 0.96 0.96 0.96 980
avg / total 0.99 0.99 0.99 10000
Hmm, not bad, but about the same as our one-neuron model did. We could do more training and add more nodes/layers. But it’ll be slow going until we improve our optimization algorithm, which we’ll do in a followup post.
So for now let’s turn to recognizing all ten digits.
## 4.1 Labels
First we need to redo our labels. We’ll re-import everything, so that we don’t have to go back and coordinate with our earlier shuffling:
mnist = fetch_mldata('MNIST original')
X, y = mnist["data"], mnist["target"]
X = X / 255
Then we’ll one-hot encode MNIST’s labels, to get a 10 x 70,000 array.
digits = 10
examples = y.shape[0]
y = y.reshape(1, examples)
Y_new = np.eye(digits)[y.astype('int32')]
Y_new = Y_new.T.reshape(digits, examples)
Then we re-split, re-shape, and re-shuffle our training set:
m = 60000
m_test = X.shape[0] - m
X_train, X_test = X[:m].T, X[m:].T
Y_train, Y_test = Y_new[:,:m], Y_new[:,m:]
shuffle_index = np.random.permutation(m)
X_train, Y_train = X_train[:, shuffle_index], Y_train[:, shuffle_index]
A quick check that things are as they should be:
i = 12
plt.imshow(X_train[:,i].reshape(28,28), cmap = matplotlib.cm.binary)
plt.axis("off")
plt.show()
Y_train[:,i]
array([0., 0., 0., 0., 0., 0., 1., 0., 0., 0.])
Looks good, so let’s consider what changes we need to make to the model itself.
## 4.2 Forward Propagation
Only the last layer of our network is changing. To add the softmax, we have to replace our lone, final node with a 10-unit layer. Its final activations are the exponentials of its $z$-values, normalized across all ten such exponentials. So instead of just computing $\sigma(z)$, we compute the activation for each unit $i$: $$\frac{e^{z_i}}{\sum_{j=0}^{9} e^{z_j}}.$$ So, in our vectorized code, the last line of forward propagation will be A2 = np.exp(Z2) / np.sum(np.exp(Z2), axis=0).
## 4.3 Cost Function
Our cost function now has to generalize to more than two classes. The general formula for $n$ classes is: $$L(y, \hat{y}) = -\sum_{i = 0}^n y_i \log(\hat{y}_i).$$ Averaging over $m$ training examples this becomes: $$L(Y, \hat{Y}) = - \frac{1}{m} \sum_{j = 0}^m \sum_{i = 0}^n y_i^{(j)} \log(\hat{y}_i^{(j)}).$$ So let’s define:
def compute_multiclass_loss(Y, Y_hat):
L_sum = np.sum(np.multiply(Y, np.log(Y_hat)))
m = Y.shape[1]
L = -(1/m) * L_sum
return L
## 4.4 Backprop
Luckily it turns out that backprop isn’t really affected by the switch to a softmax. A softmax generalizes the sigmoid activiation we’ve been using, and in such a way that the code we wrote earlier still works. We could verify this by deriving: $$\frac{\partial L}{\partial z_i} = \hat{y}_i - y_i.$$ But I won’t walk through the steps here. Let’s just go ahead and build our final network.
## 4.5 Build & Train
n_x = X_train.shape[0]
n_h = 64
learning_rate = 1
W1 = np.random.randn(n_h, n_x)
b1 = np.zeros((n_h, 1))
W2 = np.random.randn(digits, n_h)
b2 = np.zeros((digits, 1))
X = X_train
Y = Y_train
for i in range(2000):
Z1 = np.matmul(W1,X) + b1
A1 = sigmoid(Z1)
Z2 = np.matmul(W2,A1) + b2
A2 = np.exp(Z2) / np.sum(np.exp(Z2), axis=0)
cost = compute_multiclass_loss(Y, A2)
dZ2 = A2-Y
dW2 = (1./m) * np.matmul(dZ2, A1.T)
db2 = (1./m) * np.sum(dZ2, axis=1, keepdims=True)
dA1 = np.matmul(W2.T, dZ2)
dZ1 = dA1 * sigmoid(Z1) * (1 - sigmoid(Z1))
dW1 = (1./m) * np.matmul(dZ1, X.T)
db1 = (1./m) * np.sum(dZ1, axis=1, keepdims=True)
W2 = W2 - learning_rate * dW2
b2 = b2 - learning_rate * db2
W1 = W1 - learning_rate * dW1
b1 = b1 - learning_rate * db1
if (i % 100 == 0):
print("Epoch", i, "cost: ", cost)
print("Final cost:", cost)
Epoch 0 cost: 9.243960401572568
... *snip* ...
Epoch 1900 cost: 0.24585173887243117
Final cost: 0.24072776877870128
Let’s see how we did:
Z1 = np.matmul(W1, X_test) + b1
A1 = sigmoid(Z1)
Z2 = np.matmul(W2, A1) + b2
A2 = np.exp(Z2) / np.sum(np.exp(Z2), axis=0)
predictions = np.argmax(A2, axis=0)
labels = np.argmax(Y_test, axis=0)
print(confusion_matrix(predictions, labels))
print(classification_report(predictions, labels))
[[ 946 0 14 3 3 10 12 2 9 4]
[ 0 1112 3 2 1 1 2 8 3 4]
[ 3 4 937 24 10 7 8 18 8 3]
[ 4 2 17 924 1 39 4 13 26 9]
[ 0 1 10 0 905 9 11 9 10 40]
[ 12 5 2 26 3 786 15 3 24 14]
[ 8 1 19 2 9 10 902 1 9 1]
[ 2 1 13 14 3 5 1 946 9 25]
[ 5 9 16 11 5 18 3 5 868 9]
[ 0 0 1 4 42 7 0 23 8 900]]
precision recall f1-score support
0 0.97 0.94 0.95 1003
1 0.98 0.98 0.98 1136
2 0.91 0.92 0.91 1022
3 0.91 0.89 0.90 1039
4 0.92 0.91 0.92 995
5 0.88 0.88 0.88 890
6 0.94 0.94 0.94 962
7 0.92 0.93 0.92 1019
8 0.89 0.91 0.90 949
9 0.89 0.91 0.90 985
avg / total 0.92 0.92 0.92 10000
We’re at 92% accuracy across all digits, not bad! And it looks like we could still improve with more training.
But let’s work on speeding up our optimization alogirthm first. We’ll pick things up there in the next post. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 6, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9052976369857788, "perplexity": 4133.643395250033}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-13/segments/1521257649931.17/warc/CC-MAIN-20180324054204-20180324074204-00061.warc.gz"} |
http://projecteuclid.org/DPubS?service=UI&version=1.0&verb=Display&handle=euclid.aap/1253281061 | ### FCFS infinite bipartite matching of servers and customers
Caldentey René, Kaplan Edward H., and Weiss Gideon
Source: Adv. in Appl. Probab. Volume 41, Number 3 (2009), 695-730.
#### Abstract
We consider an infinite sequence of customers of types 𝓒={1,2,...,I} and an infinite sequence of servers of types 𝓢={1,2,...,J}, where a server of type j can serve a subset of customer types C(j) and where a customer of type~$i$ can be served by a subset of server types S(i). We assume that the types of customers and servers in the infinite sequences are random, independent, and identically distributed, and that customers and servers are matched according to their order in the sequence, on a first-come--first-served (FCFS) basis. We investigate this process of infinite bipartite matching. In particular, we are interested in the rate ri,j that customers of type i are assigned to servers of type j. We present a countable state Markov chain to describe this process, and for some previously unsolved instances, we prove ergodicity and existence of limiting rates, and calculate ri,j.
First Page:
Primary Subjects: 90B22
Secondary Subjects: 60J20, 68M20
We're sorry, but we are unable to provide you with the full text of this article because we are not able to identify you as a subscriber.
If you have a personal subscription to this journal, then please login. If you are already logged in, then you may need to update your profile to register your subscription. Read more about accessing full-text
Permanent link to this document: http://projecteuclid.org/euclid.aap/1253281061
Digital Object Identifier: doi:10.1239/aap/1253281061
Mathematical Reviews number (MathSciNet): MR2571314
Zentralblatt MATH identifier: 05625065
### References
Adan, I., Foley, R. D. and McDonald, D. R. (2007). Exact asymptotics of the stationary distribution of a Markov chain: a production model. EURANDOM Report 2008-036, Eindhoven, Netherlands. Available at http://www.eurandom.nl/EURANDOMreports.htm.
Aksin, Z., Armony, M. and Mehrotra, V. (2007). The modern call-center: a multi-disciplinary perspective on operations management research. Production Operat. Manag. 16, 665--688.
Brémaud, P. (1999). Markov Chains. Springer, New York.
Mathematical Reviews (MathSciNet): MR1689633
Birch, M. W. (1963). Maximum likelihood in three-way contingency tables. J. R. Statist. Soc. B 25, 220--233.
Mathematical Reviews (MathSciNet): MR168065
Bishop, Y. M. M. and Fienberg, S. E. (1969). Incomplete two-dimensional contingency tables. Biometrics 25, 119--128.
Caldentey, R. A. and Kaplan, E. H. (2002). A heavy traffic approximation for queues with restricted customer-service matchings. Unpublished manuscript.
Dao-Thi, T.-H. and Mairesse, J. (2006). Zero-automatic networks. In Proc. VALUETOOLS (Pisa, Italy), ACM, New York.
Dao-Thi, T.-H. and Mairesse, J. (2007). Zero-automatic queues and product form. Adv. Appl. Prob. 39, 502--536.
Mathematical Reviews (MathSciNet): MR2341581
Zentralblatt MATH: 1121.60094
Digital Object Identifier: doi:10.1239/aap/1183667618
Project Euclid: euclid.aap/1183667618
Durrett, R. (1995). Probability: Theory and Examples, 2nd edn. Duxbury Press, Belmont, CA.
Mathematical Reviews (MathSciNet): MR1609153
Zentralblatt MATH: 0709.60002
Fayolle, G., Malyshev, V. A. and Menshikov, M. V. (1995). Topics in the Constructive Theory of Countable Markov Chains. Cambridge University Press.
Mathematical Reviews (MathSciNet): MR1331145
Fienberg, S. E. (1970). Quasi-independence and maximum likelihood estimation in incomplete contingency tables. J Amer. Statist. Assoc. 65, 1610--1615.
Mathematical Reviews (MathSciNet): MR273768
Zentralblatt MATH: 0224.62025
Digital Object Identifier: doi:10.2307/2284344
Ford, L. R., Jr. and Fulkerson, D. R. (1962). Flows in Networks. Princeton University Press.
Mathematical Reviews (MathSciNet): MR159700
Garnett, O. and Mandelbaum, A. (2000). An introduction to skill-based routing and its operational complexities. Unpublished manuscript. Available at http://iew3.technion.ac.il/serveng/Lectures/SBR.pdf.
Goodman, L. (1968). The analysis of cross classified data: independence, quasi-independence, and interactions in contingency tables with and without missing entries. J. Amer. Statist. Assoc. 63, 1091--1131.
Hwang, N. H. C. (1981). Fundamentals of Hydraulic Engineering Systems. Prentice Hall, Englewood Cliffs, NJ.
Kaplan, E. H. (1984). Managing the demand for public housing. ORC Tech. Rep. 183, MIT.
Kaplan, E. H. (1988). A public housing queue with reneging and task-specific servers. Decision Sci. 19, 383\nobreakdash--391.
Mairesse, J. (2005). Random walks on groups and monoids with a Markovian harmonic measure. Electron. J. Prob. 10, 1417--1441.
Mathematical Reviews (MathSciNet): MR2191634
Zentralblatt MATH: 1109.60037
Mairesse, J. and Mathéus, F. (2007). Random walks on free products of cyclic groups. J. London Math. Soc. 75, 47--66. Appendix available at http://arxiv.org/abs/math/0509208.
Mathematical Reviews (MathSciNet): MR2302729
Zentralblatt MATH: 1132.60054
Digital Object Identifier: doi:10.1112/jlms/jdl006
Talreja, R. and Whitt, W. (2007). Fluid models for overloaded multiclass many-service queueing systems with FCFS routeing. Manag. Sci. 54, 1513--1527.
Zenios, S. A. (1999). Modeling the transplant waiting list: a queueing model with reneging. Queueing Systems 31, 239--251.
Mathematical Reviews (MathSciNet): MR1706048
Digital Object Identifier: doi:10.1023/A:1019162331525 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5177597999572754, "perplexity": 6518.15914163693}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368701852492/warc/CC-MAIN-20130516105732-00005-ip-10-60-113-184.ec2.internal.warc.gz"} |
https://quantumfrontiers.com/2012/08/10/universal-thread/ | How many miles per gallon?
Thoughts while watching the Olympics …
My car gets about 30 miles per gallon of gasoline. Miles per gallon has the dimensions of inverse length squared, and the reciprocal of 30 miles per gallon is roughly the area of a circle whose diameter is 0.3 mm, or about 1/100 of an inch.
That means that when I drive my car, the fuel I consume has the same volume as a thin thread stretched along the road over the distance I travel, with a thickness just a few times the width of a human hair.*
That skinny little thread of gasoline is enough to keep my car going! Thinking about it reinforces one’s appreciation for the internal combustion engine.
Okay, let’s compare with another admirable machine — the human athlete. How many calories a runner burns depends on the runner’s weight, pace, and other things, but a typical male runner burns between 100 and 150 kilocalories per mile. Over a 26 mile marathon, that comes to about 3500 kcal, roughly equivalent to a pound of fat.
The human stomach holds about a gallon. I don’t recommend this, but if the marathon runner goes to McDonald’s after the race and scarfs down a few Big Macs, orders of fries, and Cokes, he’ll fill his stomach with about as many calories as he burned during his run.
So the marathon runner also gets about 30 miles per gallon. A skinny little thread of fuel, about 0.3 mm thick, is enough to keep you and me going, too! Is that a universal constant of Nature?
Wait ’til I tell my car!
* I heard this nugget from Charlie Bennett, who, appropriately, told it to me while we were sharing a taxicab.
This entry was posted in Reflections, The expert's corner by preskill. Bookmark the permalink.
I am a theoretical physicist at Caltech, and the Director of the Institute for Quantum Information and Matter. Follow me on Twitter @preskill.
## 18 thoughts on “Universal thread”
1. Professional marathon runners aren’t typical runners, though. They’re going faster, which should be harder, but they’re able to do so because they are more efficient. I’d guess 75-80 kilocalories per mile might be closer. Quibbling here.
• Thanks. In that case, hold the fries.
2. Not exactly a universal constant—on a bicycle a human is somewhere between 5 and 10 times as efficient, depending on speed and mass.
• Yeah, wheels help a lot.
3. That’s a wonderful Fermi problem!
A natural follow-on question is this: If everyone on Earth jumped in a car, and drove 30 miles per hour, what would be the diameter of the equivalent gasoline thread, and how long would it take the continued combustion of this thread to double the CO2 level of the earth’s atmosphere?
This is a wonderfully edifying/terrifying calculation to carry through, immediately before reading arXiv:1110.1365v3.
Yes, a planet with $\mathcal{O}10^{10}$ people living on it is in a mighty serious situation. And yes too, QC/QIT/QSE does have considerable to do with getting into it and getting out of it.
4. 1kcal = 10^23 ev
If breaking a bond yields 10ev, runners and cars such at efficiency
5. Oops I posted prematurely.
I meant
1kcal = 10^23 ev
If breaking a bond yields 10ev, runners and cars are pretty inefficient by some standards: they have to break 100 kcal/mile = 10^24 bonds/mile
6. More exactly
4 kcal = 10^23 ev
7. I should have said creating bonds, not breaking bonds
8. Right. A gallon of gasoline has a lot more calories than a gallon of whole milk (more by better than a factor of 10). But we can’t drink the gasoline.
9. By the way,
1 mile is about 1/4 million angstrom = 25,000 nm.
1 Bohr radius is 1/2 angstrom.
So those runners are creating 10^18 bonds per Bohr radius of distance traveled. Pretty pityful
• This is totally wrong. Sorry.1 mile is not 1/4 million angstrom. I mis-remembered
• The correct conversion is
1 mile = 1.6X10^13 angstrom = 3.2 X 10^13 Bohr radii
so maybe its more like 10^11 bonds created per Bohr radius traveled
10. I already see Lagrangian Coherent Structures while driving. Now I’m also going to visualize a little thread coming out of my car’s arse (exhaust pipe?)!
[url=http://www.economist.com/node/14843793][The Economist’s popular explanation of Lagrangian Coherent Structures][/url]. The late Jerry Marsden introduced me to these.
• Or, when you’re running, out of yours!
• Touché! Having fun with words: out my tushy?
11. In graduate school my then-girlfriend (and future) wife was production manager for the Bulletin of the Atomic Scientists, and through her I acquired a considerable measure of respect for that fine journal, which expressed a certain gravitas with regard to the relation of physicists to the broader society. Given the concern that even non-physicists are expressing with regard to CO2-driven climate instability, it might be no bad thing if Quantum Frontiers were to imbibe some of that same broad-ranging gravitas. The present topic of energy efficiency is well-suited as a starting point.
12. Bueno, sólo me tomé la libertad de escribir un comentario en tu sitio para que veas
que si existimos personas que leen. Sólo un consejo, haz el esfuerzo revisar tu
ortografía. Considera que una mala ortografía mata hasta al
mejor artículo | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 1, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.531026303768158, "perplexity": 4324.0818240658045}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-13/segments/1521257647322.47/warc/CC-MAIN-20180320072255-20180320092255-00715.warc.gz"} |
http://mathoverflow.net/questions/21238/inhomogenous-recurrence-relations?answertab=active | # Inhomogenous recurrence relations
Would someone be able to point me to a good resource explaining step by step the process for solving inhomogenous recurrence relations? (ie something of the form $a_n = \sum{{b_i}{a_{n-i}}} + f(n)$ )
-
One standard method is generating functions. Set $A(t)=\sum_{n=0}^\infty a_n t^n$ and $B(t)=\sum_{i=1}^\infty b_i t^i$. Then $$A(t)=a_0+B(t)A(t)+\sum_n f(n)t^n$$ so that $$A(t)=(1-B(t))^{-1}\left(a_0+\sum_n f(n)t^n\right).$$ For an excellent text on generating functions, see Herb Wilf's generatingfunctionology: http://www.math.upenn.edu/~wilf/DownldGF.html . | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6684633493423462, "perplexity": 241.71645280702077}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-18/segments/1429246659483.51/warc/CC-MAIN-20150417045739-00090-ip-10-235-10-82.ec2.internal.warc.gz"} |
https://ai.stackexchange.com/questions/6762/how-to-compute-the-action-probabilities-with-thompson-sampling-in-deep-q-learnin/6764 | # How to compute the action probabilities with Thompson sampling in deep Q-learning?
In some implementations of off-policy Q-learning, we need to know the action probabilities given by the behavior policy $$\mu(a)$$ (e.g., if we want to use importance sampling).
In my case, I am using Deep Q-Learning and selecting actions using Thompson Sampling. I implemented this following the approach in "What My Deep Model Doesn't Know...": I added dropout to my Q-network and select actions by performing a single stochastic forward pass through the Q-network (i.e., with dropout enabled) and choosing the action with the highest Q-value.
So, how can I calculate $$\mu(a)$$ when using Thompson Sampling based on dropout?
So, how can I calculate $$\mu(a)$$ when using Thompson Sampling based on dropout? | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 3, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7575182318687439, "perplexity": 930.3742551900734}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-39/segments/1631780058552.54/warc/CC-MAIN-20210927211955-20210928001955-00411.warc.gz"} |
http://mymathforum.com/linear-algebra/338599-linear-inequalities.html | My Math Forum Linear inequalities
Linear Algebra Linear Algebra Math Forum
January 15th, 2017, 09:47 AM #1 Newbie Joined: Jan 2017 From: Nigeria Posts: 1 Thanks: 0 Linear inequalities X is a whole number.if three quarters of x is subtracted from 1,the result is always greater than 0.
January 15th, 2017, 11:17 AM #2 Math Team Joined: Jul 2011 From: Texas Posts: 2,219 Thanks: 1060 What if $x = 1$, a whole number (last time I checked) ... ? Thanks from Joppy
January 15th, 2017, 08:15 PM #3 Global Moderator Joined: Dec 2006 Posts: 16,400 Thanks: 1177 1 - (3/4)x > 0 is equivalent to x < 4/3.
February 16th, 2017, 05:19 AM #4
Math Team
Joined: Jan 2015
From: Alabama
Posts: 2,254
Thanks: 561
Quote:
Originally Posted by skeeter What if $x = 1$, a whole number (last time I checked) ... ?
Then $1- (3/4)x= 1- 3/4= 1/4> 0$. I don't see your point.
But if $x= 2$ then $1- (3/4)x= 1- 3/2= -1/2$. Perhaps that was what you meant?
February 23rd, 2017, 05:43 AM #5 Math Team Joined: Jan 2015 From: Alabama Posts: 2,254 Thanks: 561 In any case, the statement "X is a whole number. if three quarters of x is subtracted from 1,the result is always greater than 0" is not always true. But there was no question asked in the original post. Chriskwajaffa, was the problem to determine values of x such that the statement is true? If so, $1- (3/4)x> 0$ is the same as $1> (3/4)x$. Multiply on both sides by the positive number 4/3 (do you see why the fact that it is positive is important?) to get $4/3> x$. So the statement is true for all x less than 4/3.
Tags inequalities, linear
Thread Tools Display Modes Linear Mode
Similar Threads Thread Thread Starter Forum Replies Last Post mj1395 Elementary Math 2 July 18th, 2016 08:10 PM BadwithUsernames Algebra 4 February 11th, 2016 06:14 AM th3greenman Algebra 3 June 14th, 2015 07:05 AM bilano99 Algebra 2 April 30th, 2013 10:45 AM newatthis Linear Algebra 1 January 15th, 2009 09:44 PM
Contact - Home - Forums - Top | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 3, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6594999432563782, "perplexity": 2613.9260342369384}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-09/segments/1487501174167.41/warc/CC-MAIN-20170219104614-00489-ip-10-171-10-108.ec2.internal.warc.gz"} |
http://sky-lights.org/2017/07/03/qa-how-we-know-earths-mass/ | # Q&A: How We Know Earth’s Mass
Question: I was watching this science show where they said Earth weighed 6 zettatons. First, what the heck is a zettaton? Second, how can they possibly know what the Earth weighs? I mean, it’s not like they can put it on a scale as you would a sack of apples. — IN, Cambridge, England
Answer: The term zettatons (Zt) must refer to metric tons (t), where 1 t = 1000 kg. The metric prefix zetta = ×1021, so they’re saying Earth weighs 6×1021 metric tons. It’s actually 5.972×1021 tons (to four significant figures), but they chose to round it up to 6. FYI, the metric ton is not a base unit in the metric system. Like the radian, watt, and joule, it’s one of many derived units in common use.
Also worth noting: Astronomers prefer to speak of the mass of astronomical bodies — not their weight. The two terms are used informally as synonyms, but their meanings are very different for scientists. If you want to get the technical explanation, go here. Suffice it to say that “weight” is a force that depends on the strength of gravity (and hence location), whereas “mass” is a constant that measures the amount of matter in a given body. So saying “Earth weighs 6 zetatons” is mixing terminology because the metric ton is a measure of mass.
Scientists use the International System of Units, (aka SI or “metric system”) wherein the base unit of force is newtons (N). The base unit of mass is kilograms (kg), though many variants (gram, milligram, zettagram) are also used. Thus, Earth’s mass is 5.972×024 kg — or if you prefer metric prefixes, 5972 Yg (yottagrams). Non-standard notation must be used for the multiplier since there is currently no metric prefix higher than “yotta.”
In the British Imperial System weight is measured in units of ounces, pounds, and imperial tons, where 1 ton = 2000 pounds. Mass is measured in the obscure unit of slugs, where 1 slug = 14.5939 kg.
So we’ll just use 5.972×024 kg for the mass of the Earth to answer your second question: How do we measure that number? There are two methods possible. The first method, which is more intuitive, is shown in the graphic. We simply measure the weight of an object with known mass (in this case standard kilogram m2). From that we can calculate the value of m1 (in this case the Earth). We’ll use the equation for gravitational force discovered by Sir Isaac Newton:
Fg = Gm1m2/r2 where:
Fg = force from gravity (in N)
m1 and m2 = masses of the attracting bodies (in kg)
r = distance between the centers of the attracting bodies
G = the universal gravitational constant = 6.67408×10-11 m3/kgs2
You can see that finding the mass of the Earth involves solving that equation for m1. Problem was, when Newton first published this equation in 1687 there was no way to measure G (the proportionality constant). Doing so would require measuring the gravitational attraction between two standard masses in the lab, where the force of gravity would be on the order of 10-10 N. Forces that small were well beyond the range of 1687 measuring instruments. It wasn’t until 1798, when Henry Cavendish first measured G using a torsion balance, that calculation of Earth’s mass became possible.
The second (and less intuitive) method for finding the Earth’s mass requires combining Newton’s gravity equation with his equation for centripetal force: Fc = m(4π2R/T2). This allows you to calculate the mass of an orbited body from the parameters of any orbiting body. To find Earth’s mass we can use the Moon (or any artificial satellite). You can see how that calculation works in my Sep 28, 2015 post.
Next Week in Sky Lights ⇒ Images of Earth with Moon | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9715274572372437, "perplexity": 1020.5903516137928}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-22/segments/1526794864405.39/warc/CC-MAIN-20180521142238-20180521162238-00420.warc.gz"} |
https://math.stackexchange.com/questions/771508/first-order-ode-integrating-factor | # First order ode integrating factor
Hi could anyone help me to solve this first order differential equation.
$$2y e^{y^2}y'=2x+3 \sqrt x$$
I tried using the integrating factor method but i do not know how to find the integreating factor for this problem.
This first order differential equation is separable since the lhs is just the derivative of $e^{y^2}$ with respect to $y$. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.914742648601532, "perplexity": 58.955551476579494}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320299927.25/warc/CC-MAIN-20220129032406-20220129062406-00129.warc.gz"} |
http://math.stackexchange.com/questions/171705/calculate-the-average-number-of-cards-of-a-certain-suit-in-my-opponents-hand | # Calculate the average number of cards of a certain suit in my opponent's hand
Let's suppose that I am playing a card game with 3 other friends. One of my friends is on my team while the other 2 people are on the opposing team. The cards have just been shuffled and dealt so that each player now has 13 cards and there are 5 cards still in the deck. There is one wild card in the deck while the rest of the cards are numbered cards of one of the four suits (red, green, yellow, black). I am looking at my cards and I see that I have 4 of the 14 red cards.
Now, for the question. What is the average number of red cards that each of my opponents might have? What about my team-mate? What is the average number of red cards left in the deck?
-
Out of the $44$ cards you don't have, $10$ are red. Your opponents' cards, your teammate's cards and the left-over cards all have the same chance of $10$ in $44$ of being red, so the average number of red cards on each hand is $13\cdot\frac{10}{44}=\frac{65}{22}\approx2.95$, with $5\cdot\frac{10}{44}=\frac{25}{22}\approx1.14$ left on average.
(The numbers don't quite add up to $10$ because of rounding.) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4903061091899872, "perplexity": 87.24076351197056}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-40/segments/1443737916324.63/warc/CC-MAIN-20151001221836-00181-ip-10-137-6-227.ec2.internal.warc.gz"} |
https://artofproblemsolving.com/wiki/index.php?title=1969_Canadian_MO_Problems/Problem_2&diff=next&oldid=8601 | # Difference between revisions of "1969 Canadian MO Problems/Problem 2"
## Problem
Determine which of the two numbers , is greater for any .
## Solution
Multiplying and dividing by its conjugate,
Similarly, . We know that for all positive , so .
1969 Canadian MO (Problems) Preceded byProblem 1 1 • 2 • 3 • 4 • 5 Followed byProblem 3 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8494248986244202, "perplexity": 4639.068920526887}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-21/segments/1620243988986.98/warc/CC-MAIN-20210509122756-20210509152756-00609.warc.gz"} |
https://engineering.stackexchange.com/tags/threads/hot | # Tag Info
## Hot answers tagged threads
10
As Dave Tweed points out, the ratio of torque to tension is lower the lower the lead angle is. Since the important measure of bolt tightness is generally the tension in the bolt, we want to achieve that minimum pretension with the least effort possible. Assuming we have to maintain a certain shear area of the thread (so the the threads are stronger than the ...
10
I'm not a machinist, but I've tapped a few holes in my time. In my experience a tapered tap will handle this problem as the taper will reach down to the good threads and self align. Use some oil with the tap. I looked at your link and that tap doesn't have much taper so perhaps a more tapered tap might help if you have problems. There are any number of ...
9
I asked a friend who is a highly competent EE by day - but who restores super sized steam engines by night and collects olde heavy metal engines etc and has much experience with old large corroded items. His comments: It really depends on the specific situation. For mild steel bolts in good condition which have not been too excessively deformed, and where ...
9
For any given size of fastener and given thread pitch, a single-start thread gives you the greatest mechanical advantage in terms of the torque required to achieve a given tension. Aside from acme threads that are often used on leadscrews for mechanical motion (e.g., CNC machinery), the only other place I have seen multiple-start screws is on self-tapping ...
9
The product that you're describing (an 'expanding tap') doesn't exist, unfortunately. I had a similar problem a few years back, and actually built my own out of a Sleeve anchor, like the one pictured below. As you tighten the nut, it pulls a tapered cone inwards, pushing the sleeve apart. I loosened the nut until the sides were parallel, shaved down the ...
7
First, I want to say that I'm suspect of that material actually being ASTM A311 (though I don't have a copy of that standard available to verify.) Looking on Matweb, this material is the closest I found in the 1050 steels. This search turns up quite a few results, but from what I can tell of A311, it's for cold-drawn and stress relieved bars, but doesn't ...
7
Threads To have the thread automatically reengage some thought will have to go to the exact type of thread used. A coarse thread and maybe a slight taper will help the threads to properly engage while minimizing the chance of cross-threading or binding. Mechanism You said that eventually the inner piece will disengage from the outer piece. This doesn't ...
6
28 is a standard Threads Per Inch dimension for 1/4 and 1/2 inch screws. $\frac{25.4 \,\text{[mm/Inch]}}{28\, \text{[Threads/Inch]}} = 0.9 \,\text{[mm metric pitch]}$ The 27 seems strange to me. But I usually use metric bolts.
5
You could drill out the hole to remove the munged threads down to the remaining good threads. This should make it easier for the tap to get into the thread grove correctly. Another thought would be to grind out the damaged threads if you could get a small cylindrical grinder. (Thinking Dremel tool here)
5
The pink Arrow hole should be left smooth. If both holes have threads when you turn the screw into the pink hole as soon as it passes the gap and reaches the yellow hole, it will keep the gap space constant. Turning the screw more will just drive it into both holes while keeping the gap at the same space till the head of the screw jams onto the lower ...
4
To make this work, one side will need the "normal" righthand thread and the other a lefthand thread or a rotating connection , but threads on both ends of the nut will not change the tension.
4
A relatively inexpensive and quite useful device would be a "pocket optical comparator". They come with Several etched glass plates with features of size that you optically/visually compare to your part. I'm happy to explain more if need be. Furthermore, you can also use a two-part rapid set silicone mold material to take molded impressions of your ...
4
Metric bolts use thread pitch in millimeters. Your M3 screw likely uses the standard pitch of 0.5 millimeters. One complete rotation of the screw will advance the screw into the work piece by that amount. According to the Bolt Depot chart, there is only one standard pitch for M3 screws, although other sizes will have standard, fine, super fine pitches ...
4
The threads made by the tapper used for helicoil is not going to work with the standard size bolts. The taps used are specific STI (Screw Thread Insert) tools. But of course, if you decide the old thread is not too damaged you can use a standard tap and try to fix it.
3
In 1841 Sir Joseph Whitworth produced a paper on a universal system of screw threads. He then collected a variety of screws and proposed a universal thread using their average pitch and depth. The result was the 'Whitworth thread' with the depth and pitch of constant proportion, giving the 'V' thread a mean angle of 55 degrees and the number of threads per ...
3
Firstly, in reference to nomenclature: in ISO (metric) standards the pitch of a leadscrew is given in units of distance/revolution. However, Unified (inch series) standards, pitch is given in TPI (threads per inch). As you mentioned in your question, lead is related to pitch by $p = L/N$ where $p$ is the pitch, $L$ is the lead and $N$ is the number of starts....
3
I think the pitch is implied by the major and pitch diameter. The tolerance of these $D_{maj}$ and $D_{pitch}$ are given in ISO 965-2 I'll attempt juggling with the math in the ISO metric screw wiki, (please correct if wrong): $(3/8)H=(D_{maj}-D_{pitch})\cdot(1/2)$ $H=P\cos(30^\circ)=P\sqrt{3}/2$ \$P = \underbrace{(2/\sqrt{3})\cdot(8/3)\cdot(1/2)}_{1....
3
Well I would suggest that you don’t thread one of the items - just have a clearance hole then a locking nut. Then, to get a precise position have a hole with a locating pin - this will ensure the positioning.
3
You need clearance at the bottom of the threaded hole or shorten the depth of the thread. This is to allow for the machining process and clearance for the cutting tool. Otherwise your thread will not be a long as you specified(because the machinist needed clearance, or the machinist will break a tool or drag the tool at the bottom of the hole if they are not ...
3
The most common way to fix mangled threads, if they're really beyond fixing and if there's enough meat to open the hole a bit larger, is to use something like a heli-coil (aka : threaded insert). For a given thread, a helicoil will have a special oversized drill and tap which you use to clear out the mangled threads to a larger diameter and tap. After ...
3
A metric thread table is what you want. Table 1. Source: Anzor. So is there a standard rule of thumb, or equation about the distance the end of a screw will travel per rotation? It's not a rule of thumb - it's defined by the pitch. Conversely, how many turns it will take to travel a specific distance? Turns required = distance / pitch. Say I have ...
3
Why does the helicoil need to be inserted if you have already tapped the new threads into a hole? Can't you just put a bolt in once you've tapped new threads? Consider the case of an M5 x 0.8 tapped hole. The helicoil will need the same pitch (0.8 mm) with a larger diameter hole. Note that the M6 is a 1.0 mm pitch so even if the helicoil tap was the same ...
3
Short and simple, if you want to use the same size fastener again, you have to use a helicoil. By drilling out the old thread with the new pilot hole you have made it larger thus the fastener size will go up unless a helicoil is used to take up that change in diameter. Further more, helicoils also prevent the threads from needing to be repaired in the future,...
3
Use a planetary gearset. Drive the center continuously at the speed you want to tap. Use a mutilated gear to drive the ring in the opposite direction intermittently and at a speed that will back the chuck up. The chuck runs with the pinion gears. There needs to be a dog clutch rigged to the mutilated gear to hold the ring gear fixed when not backing it up. ...
2
I'm sure there are specific strategies relating to pipe flanges, but for the broader issue of controlling that all of your bolts are tight enough, here is some background information. When tightening bolts in any clamping application, what's really important is the total clamping force. In any simple joint, and specifically when dealing with pipe flanges, ...
2
Although i know is's not the right answer, i would like to mention that using a micrometer to measure bolt length out of nut can be helpful, because that is proportional to torque, so for same installations one can use it to check if all bolts have the same load. another option when a torque meter is not helpful is to use smart bolts. they have internal ...
2
I am not aware of anyone that makes such a beast nor have I seen one in the wild. What I have seen is head collars. collars are a tapered washer normally made of nylon but also available in metal that are designed to accommodate mismatched head taper. As they have no threads they can be used with multiple screws. Somewhere I have a box of them for #8 screws. ...
2
If you have a vendor you work with, or even if you don't work with them but you're aware of their company, then I would ask them directly for the formulas/references you should use to spec the housing for their equipment. I know from working with sales application engineers that they are very eager to help you design your system if it means you're (telling ...
2
I always cheat the thread engagement percentage in tough materials. When allowable of course, going from say 75% to 65% will make it much easier to tap. So for a M12, chart says letter "Y" drill at .404" will give you 75% engagement. I'd try going up to letter "Z" drill at .413". ONLY if you can! Otherwise, it sounds like your problem is chip extraction, the ...
2
Usually threads are done by some standard. You can use calipers to measure and than find closest in standard, if your product is from eu, its easy you need eu standards like this ISO 68-1:1998 or maybe BS pipe So the answer would be to measure as accurate as possible but also use literature. Mechanical engineering handbooks like Kraut are great to have at ...
Only top voted, non community-wiki answers of a minimum length are eligible | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5245503783226013, "perplexity": 1555.5215410689152}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-31/segments/1627046154486.47/warc/CC-MAIN-20210803222541-20210804012541-00605.warc.gz"} |
http://www.darwinproject.ac.uk/letter/DCP-LETT-6094.xml | DCP-LETT-6094
# From Edward Blyth 5 April 1868
## April 5/68.
Dear Mr. Darwin,
I am not aware that the fact of occasional syndactylism in man has ever been published. I learned it from Bartlett, who assures me that it is not uncommon, and, as I before mentioned, one of the Keepers at the Z. G. has this peculiarity. It is the 2d. & 3d. toes of the foot that are joined, as also in Hylobates.1 Certainly, I never remarked an instance among the myriads of naked feet that I have seen in India, and it would be more noticeable in people who have never cramped their feet by wearing shoes, inasmuch as their toes are straight and flexible, finger-like, and spreading. I remember being much struck with the appearance of the natural human foot when first I observed it, & I did think of procuring specimens from the dissecting rooms to send in spirit to the Col. Surg. Museum.2 In Hindu and Egyptian Sculpture the straight and finger-like toes—the foot-fingers—are represented, not so in the Greek statues. I have several times observed in the naked feet of sailors an abnormity in which the great toe exhibits a very strong tendency to be opposed to the other toes
[DIAG HERE]
the joint projecting much at a. Of these I have seen at least $\frac{1}{2}$ doz instances. There were two sailors (not related) thus characterized on board the ship in which I went to India—3
In the marsh terns (Hydrochelidon) & in the Sterna melanogaster, the seasonal change of colour is common to the two sexes; ditto with the black cap assumed in spring by most terns, & the hood of the hooded gulls.4 In Gallicrex cristatus, the frontal shield is small and pointed in winter,
[DIAG HERE]
but at the breeding season it rises into a caruncle thus,
[DIAG HERE]
being of a red colour, and at this time the males are very pugnacious, and are kept for fighting by the inhabitants of Eastern Bengal, who designate the bird the Kora. As it is one-third larger than its female, I think there can be little doubt of its being polygamous.5
The wing-plumes of the male ostrich are unquestionably much more developed than those of the female; but whether both sexes of woodpeckers incubate is more than I can tell.6 In the touracos, toucans, and barbets, there is no sexual diversity of plumage; in the trogons there is. In some hornbills also, & there is generally some difference in the colouring of the casque, and of the iris, & also any naked skin; thus in Bucorax abyssinicus the gular pouch of ♂ is bright red, in ♀ leaden-blue.7 Rollers,8 bee-eaters, & kingfishers have mostly the sexes alike, but in Ceryle rudis the ♂ only has the second black pectoral bar.9 Swainson imagined that the latter indicated a different species, & styled the ♂ Ispida bitorquata!10
Yours truly, | E Blyth.
## CD annotations
1.1 I am … India— 1.17] crossed pencil
2.1 In … gulls. 2.3] crossed dotted line, ink; ‘Terns’ pencil
2.1 In … Kora. 2.7] crossed blue crayon; ‘Blyth April 8— 68—’ in margin blue crayon
2.3 In Gallicrex … polygamous. 2.9] crossed ink
3.1 The … female; 3.2] scored blue crayon; ‘♀ Bird’ blue crayon
3.2 but … tell. 3.3] del pencil
3.3 touracos] underl blue crayon
3.3toucans] underl blue crayon; underl pencil; circled red crayon
3.3 barbets] underl blue crayon; circled red crayon
3.3 touracos … barbets,] ‘In Gould’s Book Trogons or Toucans11 pencil
## Footnotes
1
CD had asked Blyth for a reference to syndactylism in humans in his letter of 4 April [1868]. Blyth refers to Abraham Dee Bartlett and to a keeper at the Zoological Gardens, Regent’s Park, London, who has not been identified. Blyth may have mentioned the keeper at the Zoological Gardens when he met CD in London on 24 March (see letter to Roland Trimen, [21 March 1868]).
2
Blyth refers to the Hunterian Museum of the Royal College of Surgeons.
3
Blyth went to India in September 1841 (ODNB).
4
The genus Hydrochelidon is now Childonias, family Sternidae; Sterna melanogaster, the black-bellied tern, is now S. acuticauda. A number of species in the genus Larus are described as ‘hooded gulls’; they are characterised by the darker colour of head plumage, particularly during the breeding season.
5
In Descent 2: 41, CD cited Blyth on the size difference in Gallicrex cristatus (now G. cinerea, the watercock). CD mentioned the development of the red caruncle, but did not cite Blyth for the information (Descent 2: 80).
6
See letter to Edward Blyth, 4 April [1868].
7
Blyth refers to Bucorvus abyssinicus, the Abyssinian ground hornbill.
8
Rollers (family Coraciidae) belong to the order Coraciiformes, which also includes bee-eaters and kingfishers.
9
Ceryle rudis is the pied kingfisher.
10
Blyth refers to William Swainson and to Swainson 1836–7, 2: 336, where Swainson listed both Ispida bitorquata and I. torquata.
11
CD refers to John Gould’s monographs on the Ramphastidae (toucans) and Trogonidae (trogons; J. Gould 1834 and 1838). Gould noted that true toucans displayed no sexual differences in the colour of their plumage (J. Gould 1834, p. 2). He observed that trogons differed in their plumage according to both sex and maturity (J. Gould 1838, p. v).
## Summary
Discusses the human foot and its abnormalities; notes an example of syndactylism.
Gives his observations on sexual differences in coloration of terns and ostriches.
## Letter details
Letter no.
DCP-LETT-6094
From
Blyth, Edward
To
Darwin, C. R.
Sent from
London, Princess Terrace, 7
Source of text
DAR 84.1: 136, DAR 160: 213
Physical description
4pp † | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 1, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4959513545036316, "perplexity": 10806.951814876438}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-30/segments/1469257824395.52/warc/CC-MAIN-20160723071024-00197-ip-10-185-27-174.ec2.internal.warc.gz"} |
https://perminc.com/resources/publications/longitudinal-dispersion-in-heterogeneous-layered-porous-media-during-stable-and-unstable-pore-scale-miscible-displacements/ | ## Longitudinal Dispersion in Heterogeneous Layered Porous Media During Stable and Unstable Pore-Scale Miscible Displacements
Afshari, S., Hejazi, H., Kantzas, A.
DOI: 10.1016/j.advwatres.2018.06.005
Advances in Water Resources, 119, September 2018, Pages 125-141.
## ABSTRACT
Dispersion and mixing of fluids during miscible displacement in porous media are known to be strongly affected by heterogeneity and viscous fingering. In this study, direct pore-level numerical simulations are employed to model flow and solute transport during both stable and unstable miscible displacements in two-dimensional packings of circular grains. Longitudinal dispersion coefficients are then computed by fitting the numerically obtained concentration profiles to the analytical solution of the convection-dispersion equation. We observed that diffusive, mixed diffusive-advective, and mechanical dispersion regimes are present during stable displacements whereas the middle diffusive-advective regime is absent in unstable displacements due to the evolution of viscous fingers. Viscous fingering also increases the longitudinal dispersion coefficient several orders of magnitude compared to the stable displacement. The results reveal that the scale-dependency of longitudinal dispersion is a function of layering direction and viscosity contrast. During stable displacement in porous domains with no layering or with the layering perpendicular to the displacement direction, the longitudinal dispersion coefficient increases along the length of flow until it reaches an asymptotic value. When layering is in the direction of displacement, however, the scale-dependency behavior is a function of the layering pattern. In unstable displacements, however, longitudinal dispersion always exhibits an asymptotic behavior. Finally, it is observed that the effect of heterogeneity and layering on the magnitude of the longitudinal dispersion coefficient diminishes as viscosity ratio increases to higher adverse values.
A full version of this paper is available on ScienceDirect Online. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9218149185180664, "perplexity": 2051.0107078609685}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-50/segments/1606141733120.84/warc/CC-MAIN-20201204010410-20201204040410-00664.warc.gz"} |
http://www.tcs.tifr.res.in/events/kolmogorob-complexity | # Kolmogorob Complexity
## Speaker:
Using Kolmogorob Complexity, we will prove that there exist an oracle with respect to which $P$ not equal to $NP$. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9632996320724487, "perplexity": 701.3701291107276}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-04/segments/1610704820894.84/warc/CC-MAIN-20210127024104-20210127054104-00035.warc.gz"} |
http://mathhelpforum.com/differential-geometry/131138-infinity-norm-inner-product.html | 1. ## Infinity-norm and inner-product
Hey,
Could someone assist me in the following math-problem.
I want to show that the norm $\Vert \cdot \Vert_{\infty}$ does not come from an inner product.
Hint: Show that the norm $\Vert \cdot \Vert_{\infty}$ does not satisfy the paralellogram law, e.g., for
$f(x)= \left\lbrace \begin{matrix} x \hspace{0,4cm}, x\in[0,1] \\ 2-x \hspace{0,4cm}, x\in [1,2] \end{matrix} \right.$
$g(x)= \left\lbrace \begin{matrix} 1-x \hspace{0,4cm}, x\in[0,1] \\ x-1 \hspace{0,4cm}, x\in [1,2] \end{matrix} \right.$
The paralellogram law states that if $V$ is a vector space with an inner product $\langle \cdot, \cdot \rangle$ and associated norm $\Vert \cdot \Vert$, then:
$\Vert \textbf{v}+\textbf{w} \Vert^{2} + \Vert \textbf{v}-\textbf{w} \Vert^{2}= 2\left( \Vert \textbf{v} \Vert^{2} + \Vert \textbf{w} \Vert^{2} \right)$
2. Have you tried to this yourself? What problem did you have? You are told exactly what to do. What are ||f|| and ||g||? What are ||f+ g|| and ||f- g||? What is $2(||f||^2+ ||g||^2)$?
Surely you see that f+ g= 1 for all x in [0, 2] and that f- g= 2x-1 for x in [0, 1] and 3- 2x for x in [1, 2].
3. ## Infinity norm and inner-product
Hey,
Yes indeed I have tried myself. The following is what I have so far:
By definition I know that:
$\Vert h \Vert_{\infty}=\displaystyle\smash{\max_{x \in [a,b]}}\vert h(x) \vert$
It is clear that:
$\displaystyle\smash{\max_{x \in [0,2]}}\vert f(x)+g(x)\vert=1$
$\displaystyle\smash{\max_{x \in [0,1]}}\vert f(x)-g(x)\vert=\displaystyle\smash{\max_{x \in [0,1]}}\vert 2x-1\vert=1$
$\displaystyle\smash{\max_{x \in [1,2]}}\vert f(x)-g(x)\vert=\displaystyle\smash{\max_{x \in [1,2]}}\vert -2x+3\vert=1$
$\displaystyle\smash{\max_{x \in [0,2]}}\vert f(x)\vert=1$
$\displaystyle\smash{\max_{x \in [0,2]}}\vert g(x)\vert=1$
Applying the definition in the beginning we have:
$\Vert f+g \Vert_{\infty}^{2}+\Vert f-g \Vert_{\infty}^{2}=2\left( \Vert f \Vert_{\infty}^{2}+\Vert g \Vert_{\infty}^{2} \right) \Leftrightarrow$
$1+1=2(1+1) \Leftrightarrow$
$2=4$
We conclude that the norm $\Vert \cdot \Vert_{\infty}$ does not satisfy the parallelogram law. My question is : "How does this show that the infinity-norm does not come from an inner-product? Is is simply because the above shows that the infinity-norm does not fulfill the parallelogram law which is one of the requirements for a vectorspace with an inner-product and associated norm?"
Thanks.
4. Originally Posted by surjective
Hey,
Yes indeed I have tried myself. The following is what I have so far:
By definition I know that:
$\Vert h \Vert_{\infty}=\displaystyle\smash{\max_{x \in [a,b]}}\vert h(x) \vert$
It is clear that:
$\displaystyle\smash{\max_{x \in [0,2]}}\vert f(x)+g(x)\vert=1$
$\displaystyle\smash{\max_{x \in [0,1]}}\vert f(x)-g(x)\vert=\displaystyle\smash{\max_{x \in [0,1]}}\vert 2x-1\vert=1$
$\displaystyle\smash{\max_{x \in [1,2]}}\vert f(x)-g(x)\vert=\displaystyle\smash{\max_{x \in [1,2]}}\vert -2x+3\vert=1$
$\displaystyle\smash{\max_{x \in [0,2]}}\vert f(x)\vert=1$
$\displaystyle\smash{\max_{x \in [0,2]}}\vert g(x)\vert=1$
Applying the definition in the beginning we have:
$\Vert f+g \Vert_{\infty}^{2}+\Vert f-g \Vert_{\infty}^{2}=2\left( \Vert f \Vert_{\infty}^{2}+\Vert g \Vert_{\infty}^{2} \right) \Leftrightarrow$
$1+1=2(1+1) \Leftrightarrow$
$2=4$
We conclude that the norm $\Vert \cdot \Vert_{\infty}$ does not satisfy the parallelogram law. My question is : "How does this show that the infinity-norm does not come from an inner-product? Is is simply because the above shows that the infinity-norm does not fulfill the parallelogram law which is one of the requirements for a vectorspace with an inner-product and associated norm?"
Thanks.
You have proved that the parallelogram law need not apply for $\|\cdot\|_{\infty}$ but every norm satisfies this. Thus...
5. Originally Posted by Drexel28
You have proved that the parallelogram law need not apply for $\|\cdot\|_{\infty}$ but every norm satisfies this. Thus...
I think you mean every inner product, not every norm. Since $\|\cdot\|_\infty$ is a norm.
6. Originally Posted by putnam120
I think you mean every inner product, not every norm. Since $\|\cdot\|_\infty$ is a norm.
Yes, thank you. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 33, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9881320595741272, "perplexity": 360.37221745144717}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-50/segments/1480698542112.77/warc/CC-MAIN-20161202170902-00051-ip-10-31-129-80.ec2.internal.warc.gz"} |
https://vintage-expo.ru/bouncing-balls-coursework-347.html | # Bouncing Balls Coursework
Tags: Essay On The Declaration Of IndependenceTeaching Kids Critical ThinkingCreative Writing PromtsCreative Writing Summer Internships 2015Ielts English EssaysEssay On Smoking Should Be BannedFrancis Bacon Of Studies EssayBusiness Plan App For MacHuman Dignity Essay
These figures show a primary numerical calculation of almost invariant sets.
The three three-dimensional shapes are the Lorenz attractor viewed from three different angles.
Because our constant is varying from impact to impact, the invariant measure is different to before.
This means that the frequency of table phase/exit velocity combinations has changed in a precise way.
Consider a ball bouncing on a sinusoidally forced moving table.
Let $$s_t$$ represent the phase of the table at impact at time $$t$$, and $$v_t$$ represent the exit velocity of the ball immediately after impact with the table.Invariant sets are very important, as each one is a building block of the system.In chaotic dynamical systems, there are no invariant sets; there is no way to break the system up into simpler pieces.The best that one can do is to look for almost-invariant sets.These sets break the system up into pieces which are individually highly chaotic, but which have only weak chaotic connections between themselves.If we draw a curve $$(x(t), y(t), z(t))$$ in three-dimensional space, we will trace out a strange attractor known as the Lorenz attractor.An invariant set is a piece of an attractor that does not move in time.This distribution is also invariant under the evolution of the dynamical system.Being invariant means that this distribution looks the same, no matter when you observe it.\end The constant $$a$$ is a factor between 0 and 1 describing how “bouncy” the ball is, and the constant $$g$$ is a positive number describing the force applied by the table.The bouncing ball evolution defined by the above formula is an example of a dynamical system.
• ###### My Personal Strengths and Weaknesses in Netball Essay.
Strengths Weaknesses Shooting Shoulder Pass Bounce Pass Chest. apart and keeping my body straight, holding the ball above my head so that the.…
• ###### Dynamical systems, invariant measures, and almost invariant.
Bouncing Balls and Invariant Measures. Consider a ball bouncing on a sinusoidally forced moving table. Let st represent the phase of the table.…
• ###### Measurement of coefficient of restitution made easy N Farkas
We present a simple activity that permits students to determine the coefficient of restitution of bouncing balls using only a stopwatch, a metre.…
• ###### Bouncy ball lab - Abstract The purpose of this lab is to show.
View Lab Report - bouncy ball lab from MATH 232 at Bucks County. purpose of this lab is to show how different but similar objects will bounce to different heights.…
• ###### Bouncing Balls - Question Which type of ball most.
View Lab Report - Bouncing Balls from SCIENCE 101 at St. Mary's High School. Question Which type of ball most closely resembles a perfect machine?…
• ###### Coursework - schoolphysics Welcome
Practical Coursework is a really important part of many Physics courses and so it is vital that you. How the bounce of a squash ball changes with temperature…
• ###### Animation - ANOMALINA
Bouncing Ball Redux. October 2010 — college coursework, updated. Bag o' Bones. November 2003 — college coursework.…
• ###### Untitled - Code Club World Projects
This coursework is developed on GitHub, at. We need the ball to bounce off the players on the pitch. Modify the last code block.… | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5447919368743896, "perplexity": 1854.2837935082534}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-31/segments/1627046153980.55/warc/CC-MAIN-20210730185206-20210730215206-00522.warc.gz"} |
https://worldwidescience.org/topicpages/b/biphenyl+compounds.html | #### Sample records for biphenyl compounds
1. [Indoor air pollution by polychlorinated biphenyl compounds in permanently elastic sealants].
Science.gov (United States)
Burkhardt, U; Bork, M; Balfanz, E; Leidel, J
1990-10-01
A common cause for indoor pollution by polycholorinated biphenyls (PCB) are defective capacitors of luminous discharge lamps. This paper describes elastic sealing compounds as another source of PCB pollution in buildings. In several rooms of a large school building indoor concentrations of 1000 ng PCB/m3 and more were registered. The total PCB concentration in sealing compounds ranged between 124,000 and 327,000 ppm. Blood specimens drawn from the school's personnel did not show elevated PCB concentrations, but additional incorporation of PCB via the respiratory tract cannot be excluded. We do not presume that any impairment of the health has been caused by this pollutant, but we think that reduction of the PCB indoor concentrations would be advisable for prophylactic purposes. Attention should be given to so-called open PCB systems such as elastic sealing compounds. Although they have been prohibited 1978, there might be a widespread use in older buildings.
2. Intergenerational effects of endocrine-disrupting compounds: a review of the Michigan polybrominated biphenyl registry.
Science.gov (United States)
Curtis, Sarah W; Conneely, Karen N; Marder, Mary E; Terrell, Metrecia L; Marcus, Michele; Smith, Alicia K
2018-06-11
Endocrine-disrupting compounds (EDCs) are a broad class of chemicals present in many residential products that can disrupt hormone signaling and cause health problems in humans. Multigenerational cohorts, like the Michigan polybrominated biphenyl registry, are ideal for studying the effects of intergenerational exposure. Registry participants report hormone-related health problems, particularly in those exposed before puberty or those in the second generation exposed through placental transfer or breastfeeding. However, more research is needed to determine how EDCs cause health problems and the mechanisms underlying intergenerational exposure. Utilizing existing data in this registry, along with genetic and epigenetic approaches, could provide insight to how EDCs cause human disease and help to determine the risk to exposed populations and future generations.
3. Antifungal activity of schinol and a new biphenyl compound isolated from Schinus terebinthifolius against the pathogenic fungus Paracoccidioides brasiliensis.
Science.gov (United States)
Johann, Susana; Sá, Nívea P; Lima, Luciana A R S; Cisalpino, Patricia S; Cota, Betania B; Alves, Tânia M A; Siqueira, Ezequias P; Zani, Carlos L
2010-10-12
The aim of this study was to isolate and identify the antifungal compounds from the extracts of Schinus terebinthifolius (Anacardiaceae) against clinical isolates of the pathogenic fungus Paracoccidioides brasiliensis. The hexane and dichlomethane fractions from leaves and stems of S. terebinthifolius were fractionated using several chromatography techniques to afford four compounds. The compounds isolated from S. terebinthifolius were identified as schinol (1), a new biphenyl compound, namely, 4'-ethyl-4-methyl-2,2',6,6'-tetrahydroxy[1,1'-biphenyl]-4,4'-dicarboxylate (2), quercetin (3), and kaempferol (4). Compounds 1 and 2 were active against different strains of P. brasiliensis, showing a minimal inhibitory concentration value against the isolate Pb B339 of 15.6 μg/ml. The isolate Pb 1578 was more sensitive to compound 1 with a MIC value of 7.5 μg/ml. Schinol presented synergistic effect only when combined with itraconazole. The compounds isolated from S. terebinthifolius were not able to inhibit cell wall synthesis or assembly using the sorbitol assay. This work reveals for the first time the occurrence of compound 2 and discloses activity of compounds 1 and 2 against several clinical isolates of P. brasiliensis. These results justify further studies to clarify the mechanisms of action of these compounds.
4. Process for removing halogenated aliphatic and aromatic compounds from petroleum products. [Polychlorinated biphenyls; methylene chloride; perchloroethylene; trichlorofluoroethane; trichloroethylene; chlorobenzene
Science.gov (United States)
Googin, J.M.; Napier, J.M.; Travaglini, M.A.
1982-03-31
A process for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contracting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible polyhydroxy compound, such as, water, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds in the low polar or nonpolar solvent by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered for recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 2 tables.
5. Passive air sampling of polychlorinated biphenyls, organochlorine compounds, and polybrominated diphenyl ethers across Asia.
Science.gov (United States)
Jaward, Foday M; Zhang, Gan; Nam, Jae Jak; Sweetman, Andrew J; Obbard, Jeffrey P; Kobara, Yuso; Jones, Kevin C
2005-11-15
Asia is of global importance economically, yet data on ambient persistent organic pollutant levels are still sparse for the region, despite international efforts under the Stockholm Convention to identify and reduce emissions. A large-scale passive air sampling survey was therefore conducted in Asia, specifically in China, Japan, South Korea, and Singapore. Polyurethane foam disks were deployed simultaneously at 77 sites, between Sept 21 and Nov 16, 2004, and analyzed for polychlorinated biphenyls (PCBs), organochlorine compounds (hexachlorobenzene (HCB), dichlorodiphenyltrichloroethanes (DDTs), chlordane), and polybrominated diphenyl ethers (PBDEs). The meteorological conditions prevailing in the region at this time facilitated the assessment of local/regional differences in atmospheric emissions, because large-scale advection effects due to monsoons or dust storms did not occur. Air concentrations estimated assuming an average sampler uptake rate of 3.5 m3/day ranged as follows (pg m(-3)): PCBs, 5-340; HCB, 10-460; DDTs, 0.4-1800; chlordanes, 1-660; PBDEs, < 0.13-340. South Korea and Singapore generally had regionally low concentrations. Elevated concentrations of PCBs, DDTs, and HCB occurred at sites in China, higher than reported in a similar recent sampling campaign in Europe. Chlordane was highest in samples from Japan (which also had elevated levels of PCBs and DDTs) and was also elevated in some Chinese locations. PBDE levels were generally low in the region.
6. Evaluating the behavior of polychlorinated biphenyl compounds in Lake Superior using a dynamic multimedia model
Science.gov (United States)
Khan, T.; Perlinger, J. A.; Urban, N. R.
2017-12-01
Certain toxic, persistent, bioaccumulative, and semivolatile compounds known as atmosphere-surface exchangeable pollutants or ASEPs are emitted into the environment by primary sources, are transported, deposited to water surfaces, and can be later re-emitted causing the water to act as a secondary source. Polychlorinated biphenyl (PCB) compounds, a class of ASEPs, are of major concern in the Laurentian Great Lakes because of their historical use primarily as additives to oils and industrial fluids, and discharge from industrial sources. Following the ban on production in the U.S. in 1979, atmospheric concentrations of PCBs in the Lake Superior region decreased rapidly. Subsequently, PCB concentrations in the lake surface water also reached near equilibrium as the atmospheric levels of PCBs declined. However, previous studies on long-term PCB levels and trends in lake trout and walleye suggested that the initial rate of decline of PCB concentrations in fish has leveled off in Lake Superior. In this study, a dynamic multimedia flux model was developed with the objective to investigate the observed levelling off of PCB concentrations in Lake Superior fish. The model structure consists of two water layers (the epilimnion and the hypolimnion), and the surface mixed sediment layer, while atmospheric deposition is the primary external pathway of PCB inputs to the lake. The model was applied for different PCB congeners having a range of hydrophobicity and volatility. Using this model, we compare the long-term trends in predicted PCB concentrations in different environmental media with relevant available measurements for Lake Superior. We examine the seasonal depositional and exchange patterns, the relative importance of different process terms, and provide the most probable source of the current observed PCB levels in Lake Superior fish. In addition, we evaluate the role of current atmospheric PCB levels in sustaining the observed fish concentrations and appraise the need
7. Measurement and estimated health risks of volatile organic compounds and polychlorinated biphenyls in air at the Hanford Site
International Nuclear Information System (INIS)
Patton, G.W.; Cooper, A.T.; Blanton, M.L.
1994-10-01
A variety of radioactive and nonradioactive chemicals have been released in effluent streams and discharged to waste disposal facilities during the nuclear materials production period at the Hanford Site. Extensive environmental surveillance for radioactive materials has occurred at Hanford; however, only limited information is available on the types and concentrations of organic pollutants potentially present. This report describes work performed to provide the Hanford Site Surface Environmental Surveillance Project with representative air concentration data for volatile organic compounds and polychlorinated biphenyls (PCBs). US Environmental Protection Agency (USEPA) volatile organic compound sampling methods evaluated for Hanford Site use were carbon-based adsorbent traps (TO-2) and Summa air canisters (TO-14). Polychlorinated biphenyls were sampled using USEPA method (TO-4), which uses glass fiber filters and polyurethane foam adsorbent beds to collect the PCBS. This report also presents results for environmental surveillance samples collected for volatile organic compound and PCB analyses from 1990 to 1993. All measured air concentrations of volatile organic compounds and PCBs were well below applicable maximum allowable concentration standards for air contaminants. Because of the lack of ambient air concentration standards, a conservative estimate is provided of the potential human health impacts from exposure to the ambient air concentrations measured on the Hanford Site
8. Ultrasound-accelerated synthesis of biphenyl compounds using novel Pd(0) nanoparticles immobilized on bio-composite.
Science.gov (United States)
Baran, Talat
2018-07-01
This study describes (i) an eco-friendly approach for design of Pd(0) nanoparticles on a natural composite, which is composed of carboxymethyl cellulose/agar polysaccharides (CMC/AG), without using any toxic reducing agents and (ii) development of ultrasound assisted simple protocol for synthesis of biphenyl compounds. Chemical characterization studies of Pd(0) nanoparticles (Pd NPs@CMC/AG) revealed that size of the particles were in the range of 37-55 nm. Catalytic performance of Pd NPs@CMC/AG was evaluated in synthesis of various biphenyl compounds by using the ultrasound-assisted method that was developed in this study. Pd NPs@CMC/AG exhibited excellent catalytic performance by producing high reaction yields. In addition, Pd NPs@CMC/AG was successfully used up to six reaction cycles without losing its catalytic activity, indicating high reproducibility of Pd NPs@CMC/AG. Additionally, compared to conventional the methods, new ultrasound-assisted synthesis technique that was followed in this study exhibited some advantages such as shorter reaction time, greener reaction conditions, higher yields and easier work-up. Copyright © 2018 Elsevier B.V. All rights reserved.
9. Polybrominated dibenzo-p-dioxins, dibenzofurans, and biphenyls: inclusion in the toxicity equivalency factor concept for dioxin-like compounds.
Science.gov (United States)
van den Berg, Martin; Denison, Michael S; Birnbaum, Linda S; Devito, Michael J; Fiedler, Heidelore; Falandysz, Jerzy; Rose, Martin; Schrenk, Dieter; Safe, Stephen; Tohyama, Chiharu; Tritscher, Angelika; Tysklind, Mats; Peterson, Richard E
2013-06-01
In 2011, a joint World Health Organization (WHO) and United Nations Environment Programme (UNEP) expert consultation took place, during which the possible inclusion of brominated analogues of the dioxin-like compounds in the WHO Toxicity Equivalency Factor (TEF) scheme was evaluated. The expert panel concluded that polybrominated dibenzo-p-dioxins (PBDDs), dibenzofurans (PBDFs), and some dioxin-like biphenyls (dl-PBBs) may contribute significantly in daily human background exposure to the total dioxin toxic equivalencies (TEQs). These compounds are also commonly found in the aquatic environment. Available data for fish toxicity were evaluated for possible inclusion in the WHO-UNEP TEF scheme (van den Berg et al., 1998). Because of the limited database, it was decided not to derive specific WHO-UNEP TEFs for fish, but for ecotoxicological risk assessment, the use of specific relative effect potencies (REPs) from fish embryo assays is recommended. Based on the limited mammalian REP database for these brominated compounds, it was concluded that sufficient differentiation from the present TEF values of the chlorinated analogues (van den Berg et al., 2006) was not possible. However, the REPs for PBDDs, PBDFs, and non-ortho dl-PBBs in mammals closely follow those of the chlorinated analogues, at least within one order of magnitude. Therefore, the use of similar interim TEF values for brominated and chlorinated congeners for human risk assessment is recommended, pending more detailed information in the future.
10. Temporal trends of polychlorinated biphenyls, polybrominated diphenyl ethers, and perfluorinated compounds in Chinese sturgeon (Acipenser sinensis) eggs (1984-2008).
Science.gov (United States)
Jianxian, Sun; Hui, Peng; Jianying, Hu
2015-02-03
Because investigation on the temporal trends of persistent halogenated compounds (PHCs) is necessary to predict their future impacts on the environment and human health and evaluate the effectiveness of regulations on their production and usage, it is of concern to investigate annual temporal trends of PHCs in biota samples. This study examined the temporal trends of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and perfluorinated compounds (PFCs) in Chinese sturgeon (Acipenser sinensis) eggs over a period of 25 years (1984-2008), and 62 PCBs (19.2-1030 ng/g dw for total PCBs), 16 PBDEs (4.7-572 ng/g dw for total PBDEs), and 14 PFCs (26-46 ng/g dw for total PFCs) were detected. Although a decreasing temporal trend was observed for total PCBs with annual reduction rate of 3.4% (ρ = 0.005), a clear break point was observed around 1991, indicating their continuing emission in the 1980s in China. All major PBDEs showed increasing temporal trends, with annual change rates at 3.5-10.2% over the 25 years, but a sharp decreasing trend was observed after 2006, indicating a rapid response to the banning of PBDE usage in China in 2004. The greatest annual rate of increase was observed for BDE-28 (10.2%) followed by BDE-100 (7.7%), which would be due to metabolism input from higher brominated PBDEs. Significantly increasing temporal trends were observed for all PFCs, and the annual rates of increase were 7.9% and 5.9% for total perfluorinated carboxylic acids and perfluorooctanesulfonate (PFOS), respectively. A peak concentration for PFOS was observed in 1989, which may be related to the import history of PFCs in China. The present study is the first report of systematic temporal trends of PHCs in biota samples from China and shows that regulatory policy is needed to reduce their potential health and ecological risk in China considering the increasing temporal trends of PBDEs and PFCs.
11. Changes in concentrations of perfluorinated compounds, polybrominated diphenyl ethers, and polychlorinated biphenyls in Norwegian breast-milk during twelve months of lactation.
Science.gov (United States)
Thomsen, Cathrine; Haug, Line S; Stigum, Hein; Frøshaug, May; Broadwell, Sharon L; Becher, Georg
2010-12-15
At present, scientific knowledge on depuration rates of persistent organic pollutants (POPs) is limited and the previous assumptions of considerable reduction of body burdens through breast-feeding have recently been challenged. We therefore studied elimination rates of important POPs in nine Norwegian primiparous mothers and one mother breast-feeding her second child by collecting breast-milk samples (n = 70) monthly from about two weeks to up to twelve months after birth. Perfluorinated compounds (PFCs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and polychlorinated biphenyls (PCBs) were determined in the breast-milk samples. Linear mixed effect models were established for selected compounds, and significant decreases in the range of 1.2-4.7% in breast-milk concentrations per month were observed for a wide range of PCBs and PBDEs. For the first time, depuration rates for perfluorooctylsulfonate (PFOS) and perfluorooctanoic acid (PFOA) are presented, being 3.8 and 7.8% per month, respectively (p changes during the lactation period. After a year of nursing the breast-milk concentrations of PFCs, PBDEs, and PCBs were reduced by 15-94%.
12. Tests of bioaccumulation models for polychlorinated biphenyl compounds: a study of young-of-the-year bluefish in the Hudson River estuary, USA.
Science.gov (United States)
Leblanc, Lawrence A; Buckel, Jeffrey A; Conover, David O; Brownawell, Bruce J
2006-08-01
A field-based study regarding uptake of polychlorinated biphenyl compounds (PCBs) by young-of-the-year (YOY) bluefish (Pomatomus saltatrix) was initiated to test a steady-state model of bioaccumulation and trophic transfer in a rapidly growing fish. Determination of prey composition as well as size-dependent growth and specific consumption rates for YOY bluefish from separate field and laboratory studies enabled the input of these species-specific parameters into the model. Furthermore, the time and duration of the exposure of YOY bluefish to dissolved PCBs from a well-characterized system (Hudson River, USA) was well known. Patterns of accumulation of individual PCB congeners differed relative to the accumulation of total PCBs, with the greatest net accumulation occurring for the higher-molecular-weight congeners. Comparison of lipid-normalized bioaccumulation factors (BAFs) with the octanol-water partition coefficients of individual PCB congeners revealed bluefish to be above the BAFs predicted by lipid-based equilibrium partitioning, suggesting that uptake from food is an important source of PCBs in YOY bluefish. Comparison of measured BAFs with values predicted by a steady-state, food-chain model showed good first-order agreement.
13. Phytoalexins of the Pyrinae: Biphenyls and dibenzofurans
Directory of Open Access Journals (Sweden)
Cornelia Chizzali
2012-04-01
Full Text Available Biphenyls and dibenzofurans are the phytoalexins of the Pyrinae, a subtribe of the plant family Rosaceae. The Pyrinae correspond to the long-recognized Maloideae. Economically valuable species of the Pyrinae are apples and pears. Biphenyls and dibenzofurans are formed de novo in response to infection by bacterial and fungal pathogens. The inducible defense compounds were also produced in cell suspension cultures after treatment with biotic and abiotic elicitors. The antimicrobial activity of the phytoalexins was demonstrated. To date, 10 biphenyls and 17 dibenzofurans were isolated from 14 of the 30 Pyrinae genera. The most widely distributed compounds are the biphenyl aucuparin and the dibenzofuran γ-cotonefuran. The biosynthesis of the two classes of defense compounds is not well understood, despite the importance of the fruit crops. More recent studies have revealed simultaneous accumulation of biphenyls and dibenzofurans, suggesting sequential, rather than the previously proposed parallel, biosynthetic pathways. Elicitor-treated cell cultures of Sorbus aucuparia served as a model system for studying phytoalexin metabolism. The key enzyme that forms the carbon skeleton is biphenyl synthase. The starter substrate for this type-III polyketide synthase is benzoyl-CoA. In apples, biphenyl synthase is encoded by a gene family, members of which are differentially regulated. Metabolism of the phytoalexins may provide new tools for designing disease control strategies for fruit trees of the Pyrinae subtribe.
14. Micrometeorological measurement of hexachlorobenzene and polychlorinated biphenyl compound air-water gas exchange in Lake Superior and comparison to model predictions
Directory of Open Access Journals (Sweden)
M. D. Rowe
2012-05-01
Full Text Available Air-water exchange fluxes of persistent, bioaccumulative and toxic (PBT substances are frequently estimated using the Whitman two-film (W2F method, but micrometeorological flux measurements of these compounds over water are rarely attempted. We measured air-water exchange fluxes of hexachlorobenzene (HCB and polychlorinated biphenyls (PCBs on 14 July 2006 in Lake Superior using the modified Bowen ratio (MBR method. Measured fluxes were compared to estimates using the W2F method, and to estimates from an Internal Boundary Layer Transport and Exchange (IBLTE model that implements the NOAA COARE bulk flux algorithm and gas transfer model. We reveal an inaccuracy in the estimate of water vapor transfer velocity that is commonly used with the W2F method for PBT flux estimation, and demonstrate the effect of use of an improved estimation method. Flux measurements were conducted at three stations with increasing fetch in offshore flow (15, 30, and 60 km in southeastern Lake Superior. This sampling strategy enabled comparison of measured and predicted flux, as well as modification in near-surface atmospheric concentration with fetch, using the IBLTE model. Fluxes estimated using the W2F model were compared to fluxes measured by MBR. In five of seven cases in which the MBR flux was significantly greater than zero, concentration increased with fetch at 1-m height, which is qualitatively consistent with the measured volatilization flux. As far as we are aware, these are the first reported ship-based micrometeorological air-water exchange flux measurements of PCBs.
15. Dual Two-Component Regulatory Systems Are Involved in Aromatic Compound Degradation in a Polychlorinated-Biphenyl Degrader, Rhodococcus jostii RHA1 ▿ †
OpenAIRE
Takeda, Hisashi; Shimodaira, Jun; Yukawa, Kiyoshi; Hara, Naho; Kasai, Daisuke; Miyauchi, Keisuke; Masai, Eiji; Fukuda, Masao
2010-01-01
A Gram-positive polychlorinated-biphenyl (PCB) degrader, Rhodococcus jostii RHA1, degrades PCBs by cometabolism with biphenyl. A two-component BphS1T1 system encoded by bphS1 and bphT1 (formerly bphS and bphT) is responsible for the transcription induction of the five gene clusters, bphAaAbAcAdC1B1, etbAa1Ab1CbphD1, etbAa2Ab2AcD2, etbAdbphB2, and etbD1, which constitute multiple enzyme systems for biphenyl/PCB degradation. The bphS2 and bphT2 genes, which encode BphS2 and BphT2, virtually ide...
16. Draft Genome Sequence of Cupriavidus pauculus Strain KF709, a Biphenyl-Utilizing Bacterium Isolated from Biphenyl-Contaminated Soil.
Science.gov (United States)
Watanabe, Takahito; Yamazoe, Atsushi; Hosoyama, Akira; Fujihara, Hidehiko; Suenaga, Hikaru; Hirose, Jun; Futagami, Taiki; Goto, Masatoshi; Kimura, Nobutada; Furukawa, Kensuke
2015-03-26
We report the draft genome sequence of Cupriavidus pauculus strain KF709, which comprises 6,826,799 bp with 6,272 coding sequences. The strain KF709 utilizes biphenyl and degrades low-chlorinated biphenyls; however, it possesses fewer coding sequences involved in the degradation of aromatic compounds than other strains belonging to the Betaproteobacteria. Copyright © 2015 Watanabe et al.
17. Draft Genome Sequence of Cupriavidus pauculus Strain KF709, a Biphenyl-Utilizing Bacterium Isolated from Biphenyl-Contaminated Soil
OpenAIRE
Watanabe, Takahito; Yamazoe, Atsushi; Hosoyama, Akira; Fujihara, Hidehiko; Suenaga, Hikaru; Hirose, Jun; Futagami, Taiki; Goto, Masatoshi; Kimura, Nobutada; Furukawa, Kensuke
2015-01-01
We report the draft genome sequence of Cupriavidus pauculus strain KF709, which comprises 6,826,799 bp with 6,272 coding sequences. The strain KF709 utilizes biphenyl and degrades low-chlorinated biphenyls; however, it possesses fewer coding sequences involved in the degradation of aromatic compounds than other strains belonging to the Betaproteobacteria.
18. Microbial transformation and degradation of polychlorinated biphenyls
Energy Technology Data Exchange (ETDEWEB)
Field, Jim A. [Department of Chemical and Environmental Engineering, University of Arizona, PO Box 210011, Tucson, AZ 85721 (United States)], E-mail: jimfield@email.arizona.edu; Sierra-Alvarez, Reyes [Department of Chemical and Environmental Engineering, University of Arizona, PO Box 210011, Tucson, AZ 85721 (United States)
2008-09-15
This paper reviews the potential of microorganisms to transform polychlorinated biphenyls (PCBs). In anaerobic environments, higher chlorinated biphenyls can undergo reductive dehalogenation. Meta- and para-chlorines in PCB congeners are more susceptible to dechlorination than ortho-chlorines. Anaerobes catalyzing PCB dechlorination have not been isolated in pure culture but there is strong evidence from enrichment cultures that some Dehalococcoides spp. and other microorganisms within the Chloroflexi phylum can grow by linking the oxidation of H{sub 2} to the reductive dechlorination of PCBs. Lower chlorinated biphenyls can be co-metabolized aerobically. Some aerobes can also grow by utilizing PCB congeners containing only one or two chlorines as sole carbon/energy source. An example is the growth of Burkholderia cepacia by transformation of 4-chlorobiphenyl to chlorobenzoates. The latter compounds are susceptible to aerobic mineralization. Higher chlorinated biphenyls therefore are potentially fully biodegradable in a sequence of reductive dechlorination followed by aerobic mineralization of the lower chlorinated products. - Higher chlorinated biphenyls are potentially fully biodegradable in a sequence of anaerobic reductive dechlorination followed by aerobic mineralization of the lower chlorinated products.
19. Microbial transformation and degradation of polychlorinated biphenyls
International Nuclear Information System (INIS)
Field, Jim A.; Sierra-Alvarez, Reyes
2008-01-01
This paper reviews the potential of microorganisms to transform polychlorinated biphenyls (PCBs). In anaerobic environments, higher chlorinated biphenyls can undergo reductive dehalogenation. Meta- and para-chlorines in PCB congeners are more susceptible to dechlorination than ortho-chlorines. Anaerobes catalyzing PCB dechlorination have not been isolated in pure culture but there is strong evidence from enrichment cultures that some Dehalococcoides spp. and other microorganisms within the Chloroflexi phylum can grow by linking the oxidation of H 2 to the reductive dechlorination of PCBs. Lower chlorinated biphenyls can be co-metabolized aerobically. Some aerobes can also grow by utilizing PCB congeners containing only one or two chlorines as sole carbon/energy source. An example is the growth of Burkholderia cepacia by transformation of 4-chlorobiphenyl to chlorobenzoates. The latter compounds are susceptible to aerobic mineralization. Higher chlorinated biphenyls therefore are potentially fully biodegradable in a sequence of reductive dechlorination followed by aerobic mineralization of the lower chlorinated products. - Higher chlorinated biphenyls are potentially fully biodegradable in a sequence of anaerobic reductive dechlorination followed by aerobic mineralization of the lower chlorinated products
20. Determination of polydimethylsiloxane–water partition coefficients for ten 1-chloro-4-[2,2,2-trichloro-1-(4-chlorophenyl)ethyl]benzene-related compounds and twelve polychlorinated biphenyls using gas chromatography/mass spectrometry
Science.gov (United States)
Eganhouse, Robert P.
2016-01-01
Polymer-water partition coefficients (Kpw) of ten DDT-related compounds were determined in pure water at 25 °C using commercial polydimethylsiloxane-coated optical fiber. Analyte concentrations were measured by thermal desorption-gas chromatography/full scan mass spectrometry (TD–GC/MSFS; fibers) and liquid injection-gas chromatography/selected ion monitoring mass spectrometry (LI–GC/MSSIM; water). Equilibrium was approached from two directions (fiber uptake and depletion) as a means of assessing data concordance. Measured compound-specific log Kpw values ranged from 4.8 to 6.1 with an average difference in log Kpw between the two approaches of 0.05 log units (∼12% of Kpw). Comparison of the experimentally-determined log Kpw values with previously published data confirmed the consistency of the results and the reliability of the method. A second experiment was conducted with the same ten DDT-related compounds and twelve selected PCB (polychlorinated biphenyl) congeners under conditions characteristic of a coastal marine field site (viz., seawater, 11 °C) that is currently under investigation for DDT and PCB contamination. Equilibration at lower temperature and higher ionic strength resulted in an increase in log Kpw for the DDT-related compounds of 0.28–0.49 log units (61–101% of Kpw), depending on the analyte. The increase in Kpw would have the effect of reducing by approximately half the calculated freely dissolved pore-water concentrations (Cfree). This demonstrates the importance of determining partition coefficients under conditions as they exist in the field.
1. The metabolism of biphenyl
International Nuclear Information System (INIS)
Meyer, T.; Aarbakke, J.; Scheline, R.R.
1976-01-01
The metabolic disposition of 14 C-biphenyl in the rat was studied by liquid scintillation counting. The rats were given an oral dose of 14 C-biphenyl (100 mg/kg, 0.7-1.0 μci) and the total excretion of radioactivity after 96 hrs was 92.2% of the dose. Urinary excretion accounted for 84.8% and faecal excretion for 7.3% of the dose. Most of this radioactivity, 75.8% and 5.8% respectively, was excreted within 24 hrs. Only trace amounts of 14 CO 2 were detected in the expired air and 0.6% of the dose was found to be still present in the rats 96 hrs after biphenyl administration. Extraction and fractionation of the 24 hrs urine samples showed that the largest fraction (nearly 30% of the dose) consisted of conjugated phenolic metabolites. Acidic metabolites accounted for a quarter of the dose and the low levels of expired 14 CO 2 indicated that these were not products resulting from extensive degradation and decarboxylation. (author)
2. Antimicrobial activity and synergy of antibiotics with two biphenyl compounds, protosappanins A and B from Sappan Lignum against methicillin-resistant Staphylococcus aureus strains.
Science.gov (United States)
Zuo, Guo-Ying; Han, Zong-Qi; Han, Jun; Hao, Xiao-Yan; Tang, Hua-Shu; Wang, Gen-Chun
2015-10-01
This study aims to investigate antimicrobial ingredients from Sappan Lignum and to evaluate their synergy on methicillin-resistant Staphylococcus aureus strains with antibiotics. Bioactivity-guided phytochemical procedures were used to screen the active compounds. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were assayed by broth microdilution. The synergy was evaluated through checkerboard microdilution and loss of viability assays. Protosappanins A (PsA) and B (PsB) were identified from Sappan Lignum extracts. They showed active against both S. aureus and MRSA with MIC or MIC50 at 64 (PsA) and 128 (PsB) mg/L alone. When they were used in combination with antibiotics, they showed best synergy with amikacin and gentamicin with MIC50 (mg/L) of amikacin reduced more significantly from 32 to four (with PsA) and eight (with PsB), and the fractional inhibitory concentration index (FICI) ranged between 0.078 and 0.500 (FICI50 = 0.375). Moreover, the resistance of MRSA towards amikacin and gentamicin could be reversed by the Clinical and Laboratory Standards Institute criteria. The combined bactericidal mode could as well be synergy. PsA and PsB showed very low cytotoxicity in comparison with their promising activity against MRSA. Protosappanins A and B showed both alone activities and resistance reversal effects of amikacin and gentamicin against MRSA, which warrant further investigations for potential combinatory therapy of MRSA infection. © 2015 Royal Pharmaceutical Society.
3. Polychlorinated Biphenyls: In situ Bioremediation from the Environment
Science.gov (United States)
Polychlorinated biphenyls (PCBs) are a group of hydrophobic and stable organic compounds consisting of 209 possible congeners. Because of their unique physico-chemical properties, PCBs were used in a wide range of industrial applications. The properties that made PCBs useful in i...
4. Biphenyl Modulates the Expression and Function of Respiratory Oxidases in the Polychlorinated-Biphenyls Degrader Pseudomonas pseudoalcaligenes KF707
Directory of Open Access Journals (Sweden)
Federica Sandri
2017-06-01
Full Text Available Pseudomonas pseudoalcaligenes KF707 is a soil bacterium which is known for its capacity to aerobically degrade harmful organic compounds such as polychlorinated biphenyls (PCBs using biphenyl as co-metabolite. Here we provide the first genetic and functional analysis of the KF707 respiratory terminal oxidases in cells grown with two different carbon sources: glucose and biphenyl. We identified five terminal oxidases in KF707: two c(caa3 type oxidases (Caa3 and Ccaa3, two cbb3 type oxidases (Cbb31 and Cbb32, and one bd type cyanide-insensitive quinol oxidase (CIO. While the activity and expression of both Cbb31 and Cbb32 oxidases was prevalent in glucose grown cells as compared to the other oxidases, the activity and expression of the Caa3 oxidase increased considerably only when biphenyl was used as carbon source in contrast to the Cbb32 oxidase which was repressed. Further, the respiratory activity and expression of CIO was up-regulated in a Cbb31 deletion strain as compared to W.T. whereas the CIO up-regulation was not present in Cbb32 and C(caa3 deletion mutants. These results, together, reveal that both function and expression of cbb3 and caa3 type oxidases in KF707 are modulated by biphenyl which is the co-metabolite needed for the activation of the PCBs-degradation pathway.
5. Role of inhalation in exposure to polychlorinated biphenyls (PCBs)
International Nuclear Information System (INIS)
Monarca, S.; Dominici, L.; Fatigoni, C.
2007-01-01
Polychlorinated biphenyls (PCBs) are a group of aromatic compounds consisting of a biphenyl variously chlorinated. Industrial production of PCBs started in 1929 and stopped in the second half of the '70s in USA and in the late 80's and 90's in Europe. PCBs are ubiquitous pollutants. The way of human exposure to PCBs is a matter of discussion. Scientific data show that the greater exposure occurs through diet. However, other available data suggest a not marginal role of the inhalation exposure. The sources of PCBs to which population are exposed depend on the amount of redistribution of these compounds released in the environment. The aim of this work is to highlight numerous studies proving that the intake of PCBs by inhalation cannot be neglected, in particular in heavily industrialized areas and where the concentration of PCBs in the environmental matrices is particularly high
6. Evaluating Chemical Reactivity And Mechanical Stability Of Nano Palladized Iron Embedded In Activated Carbon On Dechlorination Of Polychlorinated Biphenyls
Science.gov (United States)
Remediation of contaminated sites with hydrophobic organic compounds such as polychlorinated biphenyls (PCBs) remains a scientific and technical challenge. The high stability, low aqueous solubility, and high organic affinity of PCBs make them difficult to treat. Many physical,...
7. Polychlorinated biphenyls (PCBs)
Energy Technology Data Exchange (ETDEWEB)
Brecher, R.; Smith, C.; Montemayor, B. [GlobalTox International Consultants Inc., Guelph, ON (Canada)
2001-03-01
A brief characterization of PCBs is provided, summarizing their toxicity, acute and chronic effects, genotoxicity, carcinogenicity and reproductive and developmental toxicity. A quick reference chart which includes a description of the class of compounds, synonyms, uses, environmental fate, sources, exposure and selected regulatory information, is also included.
8. Thermic decomposition of biphenyl; Decomposition thermique du biphenyle
Energy Technology Data Exchange (ETDEWEB)
Lutz, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1966-03-01
Liquid and vapour phase pyrolysis of very pure biphenyl obtained by methods described in the text was carried out at 400 C in sealed ampoules, the fraction transformed being always less than 0.1 per cent. The main products were hydrogen, benzene, terphenyls, and a deposit of polyphenyls strongly adhering to the walls. Small quantities of the lower aliphatic hydrocarbons were also found. The variation of the yields of these products with a) the pyrolysis time, b) the state (gas or liquid) of the biphenyl, and c) the pressure of the vapour was measured. Varying the area and nature of the walls showed that in the absence of a liquid phase, the pyrolytic decomposition takes place in the adsorbed layer, and that metallic walls promote the reaction more actively than do those of glass (pyrex or silica). A mechanism is proposed to explain the results pertaining to this decomposition in the adsorbed phase. The adsorption seems to obey a Langmuir isotherm, and the chemical act which determines the overall rate of decomposition is unimolecular. (author) [French] Du biphenyle tres pur, dont la purification est decrite, est pyrolyse a 400 C en phase vapeur et en phase liquide dans des ampoules scellees sous vide, a des taux de decomposition n'ayant jamais depasse 0,1 pour cent. Les produits provenant de la pyrolyse sont essentiellement: l' hydrogene, le benzene, les therphenyles, et un depot de polyphenyles adherant fortement aux parois. En plus il se forme de faibles quantites d'hydrocarbures aliphatiques gazeux. On indique la variation des rendements des differents produits avec la duree de pyrolyse, l'etat gazeux ou liquide du biphenyle, et la pression de la vapeur. Variant la superficie et la nature des parois, on montre qu'en absence de liquide la pyrolyse se fait en phase adsorbee. La pyrolyse est plus active au contact de parois metalliques que de celles de verres (pyrex ou silice). A partir des resultats experimentaux un mecanisme de degradation du biphenyle en phase
9. Thermal decomposition of biphenyl (1963); Decomposition thermique du biphenyle (1963)
Energy Technology Data Exchange (ETDEWEB)
Clerc, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1962-06-15
The rates of formation of the decomposition products of biphenyl; hydrogen, methane, ethane, ethylene, as well as triphenyl have been measured in the vapour and liquid phases at 460 deg. C. The study of the decomposition products of biphenyl at different temperatures between 400 and 460 deg. C has provided values of the activation energies of the reactions yielding the main products of pyrolysis in the vapour phase. Product and Activation energy: Hydrogen 73 {+-} 2 kCal/Mole; Benzene 76 {+-} 2 kCal/Mole; Meta-triphenyl 53 {+-} 2 kCal/Mole; Biphenyl decomposition 64 {+-} 2 kCal/Mole; The rate of disappearance of biphenyl is only very approximately first order. These results show the major role played at the start of the decomposition by organic impurities which are not detectable by conventional physico-chemical analysis methods and the presence of which accelerates noticeably the decomposition rate. It was possible to eliminate these impurities by zone-melting carried out until the initial gradient of the formation curves for the products became constant. The composition of the high-molecular weight products (over 250) was deduced from the mean molecular weight and the dosage of the aromatic C - H bonds by infrared spectrophotometry. As a result the existence in tars of hydrogenated tetra, penta and hexaphenyl has been demonstrated. (author) [French] Les vitesses de formation des produits de decomposition du biphenyle: hydrogene, methane, ethane, ethylene, ainsi que des triphenyles, ont ete mesurees en phase vapeur et en phase liquide a 460 deg. C. L'etude des produits de decomposition du biphenyle a differentes temperatures comprises entre 400 et 460 deg. C, a fourni les valeurs des energies d'activation des reactions conduisant aux principaux produits de la pyrolyse en phase vapeur. Produit et Energie d'activation: Hydrogene 73 {+-} 2 kcal/Mole; Benzene 76 {+-} 2 kcal/Mole; Metatriphenyle, 53 {+-} 2 kcal/Mole; Decomposition du biphenyle 64 {+-} 2 kcal/Mole; La
10. A new biphenyl derivative from the mangrove endophytic fungus Phomopsis longicolla HL-2232.
Science.gov (United States)
Li, Xiao-Bao; Chen, Guang-Ying; Liu, Rui-Jie; Zheng, Cai-Juan; Song, Xin-Ming; Han, Chang-Ri
2017-10-01
A new biphenyl derivative 5,5'-dimethoxybiphenyl-2,2'-diol (1), together with five known compounds (2-5), was isolated from the mangrove endophytic fungus Phomopsis longicolla HL-2232. The structures of these compounds were elucidated using comprehensive spectroscopic methods. The absolute configuration of 4 was determined by single-crystal X-ray diffraction for the first time. The inhibitory activities of all compounds against two Vibrio bacteria were evaluated.
11. Synergistic Processing of Biphenyl and Benzoate: Carbon Flow Through the Bacterial Community in Polychlorinated-Biphenyl-Contaminated Soil
Science.gov (United States)
Leewis, Mary-Cathrine; Uhlik, Ondrej; Leigh, Mary Beth
2016-02-01
Aerobic mineralization of PCBs, which are toxic and persistent organic pollutants, involves the upper (biphenyl, BP) and lower (benzoate, BZ) degradation pathways. The activity of different members of the soil microbial community in performing one or both pathways, and their synergistic interactions during PCB biodegradation, are not well understood. This study investigates BP and BZ biodegradation and subsequent carbon flow through the microbial community in PCB-contaminated soil. DNA stable isotope probing (SIP) was used to identify the bacterial guilds involved in utilizing 13C-biphenyl (unchlorinated analogue of PCBs) and/or 13C-benzoate (product/intermediate of BP degradation and analogue of chlorobenzoates). By performing SIP with two substrates in parallel, we reveal microbes performing the upper (BP) and/or lower (BZ) degradation pathways, and heterotrophic bacteria involved indirectly in processing carbon derived from these substrates (i.e. through crossfeeding). Substrate mineralization rates and shifts in relative abundance of labeled taxa suggest that BP and BZ biotransformations were performed by microorganisms with different growth strategies: BZ-associated bacteria were fast growing, potentially copiotrophic organisms, while microbes that transform BP were oligotrophic, slower growing, organisms. Our findings provide novel insight into the functional interactions of soil bacteria active in processing biphenyl and related aromatic compounds in soil, revealing how carbon flows through a bacterial community.
12. Synthesis and Screening of Novel Substituted Biphenyl Proteomimetics as Potential Anti-Estrogenic Agents for the Treatment of Hormone-Responsive Breast Cancer
National Research Council Canada - National Science Library
Hanson, Robert N
2005-01-01
.... The specific aims involved preparing the requisite aryl halide and boronic acid intermediates, coupling to generate the small biphenyl library and evaluating the compounds in a competitive binding assay...
13. The need and Potential of Biosensors to Detect Dioxins and Dioxin-Like Polychlorinated Biphenyls along the Milk, Eggs and Meat Food Chain
NARCIS (Netherlands)
Chobtang, J.; Boer, de I.J.M.; Hoogenboom, L.A.P.; Haasnoot, W.; Kijlstra, A.; Meerburg, B.G.
2011-01-01
Dioxins and dioxin-like polychlorinated biphenyls (DL-PCBs) are hazardous toxic, ubiquitous and persistent chemical compounds, which can enter the food chain and accumulate up to higher trophic levels. Their determination requires sophisticated methods, expensive facilities and instruments,
14. EFFECTS OF POLYCHLORINATED-BIPHENYLS (PCBS) AND DIOXINS ON GROWTH AND DEVELOPMENT
NARCIS (Netherlands)
SAUER, PJJ; HUISMAN, M; KOOPMANESSEBOOM, C; MORSE, DC; SMITSVANPROOIJE, AE; VANDEBERG, KJ; TUINSTRA, LGMT; VANDERPAAUW, CG; BOERSMA, ER; WEISGLASKUPERUS, N; LAMMERS, JHCM; KULIG, BM; BROUWER, A
1994-01-01
Polychlorinated biphenyls (PCBs) and dioxins are potentially toxic compounds which occur widely in the environment. Their effects on the growth and development of infants at the levels currently found in highly industrialised western countries is not well known. This Dutch multicenter study,
International Nuclear Information System (INIS)
West, O.R.; Liang, L.; Holden, W.L.
1996-06-01
Contamination from polychlorinated biphenyls (PCBs) is a persistent problem within the Department of Energy complex, as well as in numerous industrial sites around the US. To date, commercially available technologies for destroying these highly stable compounds involve degradation at elevated temperatures either through incineration or base-catalyzed dehalogenation at 300 degrees C. Since the heating required with these processes substantially increases the costs for treatment of PCB-contaminated wastes, there is a need for finding an alternative approach where PCB can be degraded at ambient temperatures. This report describes the degradation of PCB's utilizing the bimetallic substrate of iron/palladium
16. Polychlorinated biphenyls: persistent pollutants with immunological, neurological, and endocrinological consequences.
Science.gov (United States)
Crinnion, Walter J
2011-03-01
Polychlorinated biphenyls (PCBs) are considered "persistent organic pollutants;" fat-soluble compounds that bioaccumulate in individuals and bio-magnify in the food chain. PCBs were the first industrial compounds to experience a worldwide ban on production because of their potent toxicity. These compounds are still present in our food supply (fish, dairy, hamburger, and poultry being the most contaminated) and our bodies. Once in the body, they can cause long-term problems, especially for those exposed in utero. PCB bioaccumulation can lead to reduced infection fighting ability, increased rates of autoimmunity, cognitive and behavioral problems, and hypothyroidism. Some research also links PCBs to increased rates of type 2 diabetes. Testing is currently available for some of the most damaging PCBs. The testing compares individual levels to national reference values and can be interpreted to determine current exposure. Dietary measures can be enacted that will reduce PCB half-lives in humans by increasing excretion.
17. Polychlorinated biphenyls in honey bees
Energy Technology Data Exchange (ETDEWEB)
Morse, R.A.; Culliney, T.W.; Gutenmann, W.H.; Littman, C.B.; Lisk, D.J.
1987-02-01
Honey bees (Apis mellifera L.) may traverse a radius of several miles from their hives and contact innumerable surfaces during their collection of nectar, pollen, propolis and water. In the process, they may become contaminated with surface constituents which are indicative of the type of environmental pollution in their particular foraging area. Honey has also been analyzed as a possible indicator of heavy metal pollution. Insecticides used in the vicinity of bee hives have been found in bees and honey. It has been recently reported that appreciable concentrations of polychlorinated biphenyls (PCBs) have been found in honey bees sampled throughout Connecticut. In the work reported here, an analytical survey was conducted on PCBs in honey bees, honey, propolis and related samples in several states to learn the extent of contamination and possible sources.
18. Hybrid pseudomonads engineered by two-step homologous recombination acquire novel degradation abilities toward aromatics and polychlorinated biphenyls
Energy Technology Data Exchange (ETDEWEB)
Suenaga, Hikaru [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan). Bioproduction Research Inst.; Nonaka, Kazuhiko; Goto, Masatoshi [Kyushu Univ., Fukuoka (Japan). Dept. of Bioscience and Biotechnology; Fujihara, Hidehiko; Furukawa, Kensuke [Beppu Univ. (Japan). Dept. of Fermentation and Food Science
2010-10-15
Pseudomonas pseudoalcaligenes KF707 possesses a chromosomally encoded bph gene cluster responsible for the catabolism of biphenyl and polychlorinated biphenyls. Previously, we constructed chimeric versions of the bphA1 gene, which encodes a large subunit of biphenyl dioxygenase, by using DNA shuffling between bphA1 genes from P. pseudoalcaligenes KF707 and Burkholderia xenovorans LB400. In this study, we demonstrate replacement of the bphA1 gene with chimeric bphA1 sequence within the chromosomal bph gene cluster by two-step homologous recombination. Notably, some of the hybrid strains acquired enhanced and/or expanded degradation capabilities for specific aromatic compounds, including single aromatic hydrocarbons and polychlorinated biphenyls. (orig.)
19. Molecular Descriptors Family on Structure Activity Relationships 6. Octanol-Water Partition Coefficient of Polychlorinated Biphenyls
Directory of Open Access Journals (Sweden)
Lorentz JÄNTSCHI
2006-01-01
Full Text Available Octanol-water partition coefficient of two hundred and six polychlorinated biphenyls was model by the use of an original method based on complex information obtained from compounds structure. The regression analysis shows that best results are obtained in four-varied model (r2 = 0.9168. The prediction ability of the model was studied through leave-one-out analysis (r2cv(loo = 0.9093 and in training and test sets analysis. Modeling the octanol-water partition coefficient of polychlorinated biphenyls by integration of complex structural information provide a stable and performing four-varied model, allowing us to make remarks about relationship between structure of polychlorinated biphenyls and associated octanol-water partition coefficients.
20. Isolation and characterization of a novel polychlorinated biphenyl-degrading bacterium, Paenibacillus sp. KBC101
Energy Technology Data Exchange (ETDEWEB)
Sakai, M.; Ezaki, S.; Suzuki, N.; Kurane, R. [Kubota Corporation, Ryuugasaki City (Japan). Biotechnology Research Centre
2005-07-01
The biphenyl-utilizing bacterial strain KBC101 has been newly isolated from soil. Biphenyl-grown cells of KBC101 efficiently degraded di- to nonachlorobiphenyls. The isolate was identified as Paenibacillus sp. with respect to its 16S rDNA sequence and fatty acid profiles, as well as various biological and physiological characteristics. In the case of highly chlorinated biphenyl (polychlorinated biphenyl; PCB) congeners, the degradation activities of this strain were superior to those of the previously reported strong PCB degrader, Rhodococcus sp. RHA1. Recalcitrant coplanar PCBs, such as 3,4,3',4'-CB, were also efficiently degraded by strain KBC101 cells. This is the first report of a representative of the genus Paenibacillus capable of degrading PCBs. In addition to growth of biphenyl, strain KBC101 could grow on dibenzofuran, xanthene, benzophenone, anthrone, phenanthrene, napthalene, fluorene, fluoranthene, and chrysene as sole sources of carbon and energy. Paenibacillus sp. strain KBC101 presented heterogeneous degradation profiles toward various aromatic compounds. (orig.)
1. Laboratory evaluation of polychlorinated biphenyls ...
Science.gov (United States)
Effectiveness and limitations of the encapsulation method for reducing polychlorinated biphenyls (PCBs) concentrations in indoor air and contaminated surface have been evaluated in the laboratory study. Ten coating materials such as epoxy and polyurethane coatings, latex paint, and petroleum-based paint were tested in small environmental chambers to rank the encapsulants by their resistance to PCB sorption and estimate the key parameters required by a barrier model. Wipe samples were collected from PCB contaminated surface encapsulated with the coating materials to rank the encapsulants by their resistance to PCB migration from the source. A barrier model was used to calculate the PCB concentrations in the sources and the encapsulant layers, and at the exposed surfaces of the encapsulant and in the room air at different times. The performance of the encapsulants was ranked by those concentrations and PCB percent reductions. Overall, the three epoxy coatings performed better than the other coatings. Both the experimental results and the mathematical modeling showed that selecting proper encapsulants can effectively reduce the PCB concentrations at the exposed surfaces. The encapsulation method is most effective for contaminated surfaces that contain low levels of PCBs. This study answers some of these questions by using a combination of laboratory testing and mathematical modeling. The results should be useful to mitigation engineers, building owners and managers
2. Optical detection of polychlorinated biphenyls
Science.gov (United States)
Kuncova, Gabriela; Berkova, Daniela; Burkhard, Jiri; Demnerova, Katerina; Pazlarova, Jarmila; Triska, Jan; Vrchotova, Nadezda
1999-12-01
In this paper we describe the detection of polychlorinated biphenyls (PCBs) which is based on the measurement of changes of optical absorption at 400 nm of the medium in an aerobic bioreactor with immobilized cells Pseudomonas species 2. The rate of production, composition and the concentration of yellow intermediates are influenced by concentration and composition of PCB mixtures, concentration of cells and by the methods of immobilization. The method was applied in the detection of commercial mixture D103. It was found that the advantageous carriers were inorganic or organic-inorganic matrices, which sorbed PCBs and a cell outgrowth from their surface was low. In water contaminated with transformer oil and chlorinated hydrocarbons the detection limit is 10-2 gD103/kg. In transformer oil the upper limit for degradation of D103 by sodium dehalogenation (1.5 gD103 /kgoil) was determined also in the presence of the same concentration of trichloroethylene. The employment to of a liquid core waveguide spectrophotometer instead of a diode array spectrophotometer increased the sensitivity of the measurement of yellow intermediates by a factor of 100. An extrinsic fiber-optic sensor was used for in-situ measurement during biodegradation of PCBs in bioreactors.
3. Analytical method of polychlorinated biphenyls(PCBs) in transformer oil
Energy Technology Data Exchange (ETDEWEB)
Shin, S.K. [National Institute of Environmental Research, Incheon (Korea); Kim, H.J.; Chung, D.; Kim, K.S.; Kim, J.K.; Chung, Y.H.; Chung, I.R.
2004-09-15
Polychlorinated biphenyls (PCBs) is a chlorinated biphenyl compound with the general formula C{sub 12}H{sub 10-n}/Cl{sub n}. PCBs generally occur as mixtures, where n can vary from 1 to 10. The 10 sites available for possible chlorine substitution result in 209 possible PCB congeners. There is now considerable concern regarding; the presence of PCB congeners in insulating oils used within large-scale electrical supply systems. Due to its outstanding chemical and thermal stabilities and electrical insulation properties, the commercial and industrial products of polychlorinated biphenyls (PCBs), such as Aroclors, Kaneclors, Clophens, Phenaclors etc., had been widely used as thermal oil and transformer oil from 1930s until the 1970s. PCBs from a group of persistent organic pollutants of the environment, especially dangerous to living organisms due to high toxicity, persistency, and bio-concentration in adipose tissue. Despite of this fact, PCB-contaminated oils are still commonly encountered partly because PCBs used as dielectric liquids in transformer and condenser. The source of PCBs in environments can range from used transformer oils or dielectric liquids to liquid wastes, and some PCBs contamination is occurred due to the re-use of incompletely reconditioned oil. The current action plan of Republic of Korea dictates that organizations with electrical equipment contaminated with more than 2 mg/L PCBs will need to treat as PCBs-containing wastes, and 50mg/L of PCBs or PCBs equivalent to be treated as a pure PCB preparation. In this study, transformer oils analyzed based on guideline for PCBs analytical method of transformer oil in Korea.
4. 21 CFR 109.30 - Tolerances for polychlorinated biphenyls (PCB's).
Science.gov (United States)
2010-04-01
... Tolerances for polychlorinated biphenyls (PCB's). (a) Polychlorinated biphenyls (PCB's) are toxic, industrial chemicals. Because of their widespread, uncontrolled industrial applications, PCB's have become a persistent... unavoidable environmental or industrial contaminants are established for a sufficient period of time following...
5. C-Aryl glucoside SGLT2 inhibitors containing a biphenyl motif as potential anti-diabetic agents.
Science.gov (United States)
Ding, Yuyang; Mao, Liufeng; Xu, Dengfeng; Xie, Hui; Yang, Ling; Xu, Hongjiang; Geng, Wenjun; Gao, Yong; Xia, Chunguang; Zhang, Xiquan; Meng, Qingyi; Wu, Donghai; Zhao, Junling; Hu, Wenhui
2015-07-15
A series of highly active C-aryl glucoside SGLT2 inhibitors containing a biphenyl motif were designed and synthesized for biological evaluation. Among the compounds tested, compound 16l demonstrated high inhibitory activity against SGLT2 (IC50=1.9 nM) with an excellent pharmacokinetic profile. Further study indicated that the in vivo efficacy of compound 16l was comparable to that of dapagliflozin, suggesting that further development would be worthwhile. Copyright © 2015 Elsevier Ltd. All rights reserved.
6. Plant enzymes in metabolism of polychlorinated biphenyls
Czech Academy of Sciences Publication Activity Database
Chromá, L.; Moeder, M.; Kučerová, P.; Macek, Tomáš; Macková, M.
2003-01-01
Roč. 12, č. 3 (2003), s. 291-295 ISSN 1018-4619 R&D Projects: GA MŠk ME 498 Institutional research plan: CEZ:AV0Z4055905 Keywords : polychlorinated biphenyls * plants * peroxidases Subject RIV: CE - Biochemistry Impact factor: 0.325, year: 2003
7. Updated Abraham solvation parameters for polychlorinated biphenyls
NARCIS (Netherlands)
van Noort, P.C.M.; Haftka, J.J.H.; Parsons, J.R.
2010-01-01
This study shows that the recently published polychlorinated biphenyl (PCB) Abraham solvation parameters predict PCB air−n-hexadecane and n-octanol−water partition coefficients very poorly, especially for highly ortho-chlorinated congeners. Therefore, an updated set of PCB solvation parameters was
8. Updated Abraham solvation parameters for polychlorinated biphenyls
NARCIS (Netherlands)
Noort, van P.C.M.; Haftka, J.J.H.; Parsons, J.R.
2010-01-01
This study shows that the recently published polychlorinated biphenyl (PCB) Abraham solvation parameters predict PCB air-n-hexadecane and n-octanol-water partition coefficients very poorly, especially for highly ortho-chlorinated congeners. Therefore, an updated set of PCB solvation parameters was
9. Kinetics of polychlorinated biphenyl partitioning to marine Chrysophyte Isochrysis galbana
International Nuclear Information System (INIS)
Ko, Fung-Chi; Baker, Joel E.; Tew, Kwee S.
2012-01-01
This study focused on the uptake kinetics of polychlorinated biphenyl (PCB) congeners by the Chrysophyte, Isochrysis galbana. A gas-purging experimental system was used to maintain constant dissolved PCB concentrations. Three phases of absorption were observed: first, a rapid absorption phase within the first 15 min, second, a first order process reaching the maximum concentration within 48 h of exposure, and third, a plateau phase as yet to be determined with very slight increases in concentration. In this study, the percentage of the maximum concentration reached within the first phase varied from 10% to 67%, depending on the size of the PCB (as determined by molecular weight and total surface area), whereas the uptake rate (k u ) during the second phase was more comparable across different PCBs. In addition, for the first phase, the bioconcentration factor (BCF) of PCBs deviated from its expected relationship with hydrophobicity, as determined by K ow , and was instead related to the molecular structure of the compound.
10. Analysis the mixtures of polyphenyls by gas chromatrogaphie. 1.- Area response for biphenyl and terphenyls relative to triphenylmethane
International Nuclear Information System (INIS)
Perez Garcia, M.
1966-01-01
The relative performances of the thermal conductivity and flame ionization detectors towards triphenylmethane were investigated for each one of the components of biphenyl of biphenyl and terphenyl mixtures. The influence of the concentration of the considered compound as well as the influence derived from the present of all other components on the above-mentioned relative performance were studied. A 2 m long column filled with 50-70 mesh stomacher containing 20% apiezon L was used to carry out the study with the thermal conductivity detector by keeping the column at 300 degree centigree using helium gas as carrier. (Author) 13 refs
11. Phytoremediation of Polychlorinated Biphenyls: New Trends and Promises
Science.gov (United States)
Van Aken, Benoit; Correa, Paola A.; Schnoor, Jerald L.
2011-01-01
Transgenic plants and associated bacteria constitute a new generation of genetically modified organisms for efficient and environmental-friendly treatment of soil and water contaminated with polychlorinated biphenyls (PCBs). This review focuses on recent advances in phytoremediation for the treatment of PCBs, including the development of transgenic plants and associated bacteria. Phytoremediation, or the use of higher plants for rehabilitation of soil and groundwater, is a promising strategy for cost-effective treatment of sites contaminated by toxic compounds, including toxic PCBs. Plants can help mitigate environmental pollution by PCBs through a range of mechanisms: besides uptake from soil (phytoextraction), plants are capable of enzymatic transformation of PCBs (phytotransformation); by releasing a variety of secondary metabolites, plants also enhance the microbial activity in the root zone, improving biodegradation of PCBs (rhizoremediation). However, because of their hydrophobicity and chemical stability, PCBs are only slowly taken up and degraded by plants and associated bacteria, resulting in incomplete treatment and potential release of toxic metabolites into the environment. Moreover, naturally occurring plant-associated bacteria may not possess the enzymatic machinery necessary for PCB degradation. In order to overcome these limitations, bacterial genes involved in the metabolism of PCBs, such as biphenyl dioxygenases, have been introduced into higher plants, following a strategy similar to the development of transgenic crops. Similarly, bacteria have then been genetically modified that exhibit improved biodegradation capabilities and are able to maintain stable relationships with plants. Transgenic plants and associated bacteria bring hope for a broader and more efficient application of phytoremediation for the treatment of PCBs. PMID:20384372
12. Exposure Monitoring and Risk Assessment of Biphenyl in the Workplace
OpenAIRE
Kim, Hyeon-Yeong; Shin, Sae-Mi; Ham, Miran; Lim, Cheol-Hong; Byeon, Sang-Hoon
2015-01-01
This study was performed to assess exposure to and the risk caused by biphenyl in the workplace. Biphenyl is widely used as a heat transfer medium and as an emulsifier and polish in industry. Vapor or high levels of dust inhalation and dermal exposure to biphenyl can cause eye inflammation, irritation of respiratory organs, and permanent lesions in the liver and nervous system. In this study, the workplace environment concentrations were assessed as central tendency exposure and reasonable ma...
13. Determination of vaporization enthalpies of polychlorinated biphenyls by correlation gas chromatography.
Science.gov (United States)
Puri, S; Chickos, J S; Welsh, W J
2001-04-01
The vaporization enthalpies of 16 polychlorinated biphenyls have been determined by correlation gas chromatography. This study was prompted by the realization that the vaporization enthalpy of the standard compounds used in previous studies, octadecane and eicosane, were values measured at 340 and 362 K, respectively, rather than at 298 K. Adjustment to 298 K amounts to a 7-8 kJ/mol increment in the values. With the inclusion of this adjustment, vaporization enthalpies evaluated by correlation gas chromatography are in good agreement with the values determined previously in the literature. The present results are based on the vaporization enthalpies of several standards whose values are well established in the literature. The standards include a variety of n-alkanes and various chlorinated hydrocarbons. The vaporization enthalpies of PCBs increased with the number of chlorine atoms and were found to be larger for meta- and para-substituted polychlorinated biphenyls.
14. Isolation and identification of aerobic polychlorinated biphenyls degrading bacteria
Directory of Open Access Journals (Sweden)
Bibi Fatemeh Nabavi
2013-01-01
Full Text Available Aims: The purpose of this study was to isolate and identify aerobic polychlorinated biphenyls (PCBs degrading bacteria. Materials and Methods: This study was performed in lab scale aerobic sequencing batch biofilm reactor. Polyurethane foams were used as bio-carrier and synthetic wastewater was prepared with PCBs in transformer oil as the main substrate (20-700 μg/l and acetone as a solvent for PCBs as well as microelements. After achieving to adequate microbial population and acclimation of microorganisms to PCB compounds with high efficiency of PCB removal, identification of degrading microbial species was performed by 16s rRNA gene sequencing of isolated bacteria. Results: Gene sequencing results of the isolated bacteria showed that Rhodococcus spp., Pseudomonas spp., Pseudoxanthomonas spp., Agromyces spp., and Brevibacillus spp. were dominant PCB-degrading bacteria. Conclusion: PCB compounds can be degraded by some microorganisms under aerobic or anaerobic conditions or at least be reduced to low chlorinated congeners, despite their chemical stability and toxicity. Based on the results of the study, five bacterial species capable of degrading PCBs in transformer oil have been identified.
15. Dioxins, furans, and polychlorinated biphenyls in hen eggs – a new source of hazard for consumers?
Directory of Open Access Journals (Sweden)
2015-12-01
Full Text Available The paper presents the results of testing eggs for the content of dioxins and polychlorinated biphenyls (PCBs, determination of the sources that caused the presence of high concentrations of these compounds which exceeded the acceptable contamination levels, and assessment of consumer health risk caused by the consumption of eggs with excessive contents of investigated compounds. In about 9% of free range eggs and 17% of organic eggs, the content of PCDD/Fs was two- or threefold higher than the acceptable limits, and in some samples the concentration of investigated compounds exceeded the maximum concentration levels. Based on the profile of the compounds, it was confirmed in several cases that their main source was the soil or unsecured refuse. The consumers of eggs and meat produced under these conditions constitute the risk groups, and their dioxin and PCB intake may exceed toxicological reference values.
16. Process for removing polychlorinated biphenyls from soil
Science.gov (United States)
Hancher, C.W.; Saunders, M.B.; Googin, J.M.
1984-11-16
The present invention relates to a method of removing polychlorinated biphenyls from soil. The polychlorinated biphenyls are extracted from the soil by employing a liquid organic solvent dispersed in water in the ratio of about 1:3 to 3:1. The organic solvent includes such materials as short-chain hydrocarbons including kerosene or gasoline which are immiscible with water and are nonpolar. The organic solvent has a greater affinity for the PCB's than the soil so as to extract the PCB's from the soil upon contact. The organic solvent phase is separated from the suspended soil and water phase and distilled for permitting the recycle of the organic solvent phase and the concentration of the PCB's in the remaining organic phase. The present process can be satisfactorily practiced with soil containing 10 to 20% petroleum-based oils and organic fluids such as used in transformers and cutting fluids, coolants and the like which contain PCB's. The subject method provides for the removal of a sufficient concentration of PCB's from the soil to provide the soil with a level of PCB's within the guidelines of the Environmental Protection Agency.
17. Accumulation of pyrethroid compounds in primary cultures of rat cortical neurons
Science.gov (United States)
Recent studies have demonstrated that lipophilic compounds (e.g. methylmercury, polychlorinated biphenyls (PCBs) and polybrominated diphenylethers (PBDEs)) rapidly accumulate in cells in culture to concentrations much higher than in the surrounding media. Primary cultures of neur...
18. DEPENDENCY OF POLYCHLORINATED BIPHENYL AND POLYCYCLIC AROMATIC HYDROCARBON BIOACCUMULATION IN MYA ARENARIA ON BOTH WATER COLUMN AND SEDIMENT BED CHEMICAL ACTIVITIES
Science.gov (United States)
The bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) by the filter-feeding soft-shell clam Mya arenaria was evaluated at three sites near Boston (MA, USA) by assessing the chemical activities of those hydrophobic organic compounds (H...
19. Detection of Surface-Linked Polychlorinated Biphenyls using Surface-Enhanced Raman Scattering Spectroscopy
DEFF Research Database (Denmark)
Rindzevicius, Tomas; Barten, Jan; Vorobiev, Mikhail
2017-01-01
We present an improved procedure for analytical detection of toxic polychlorinated biphenyls (PCB) using surface-enhanced Raman scattering (SERS) spectroscopy. A gold-capped silicon nanopillar substrate was utilized to concentrate PCB molecules within an area of high electromagnetic fields through...... formation of microsized nanopillar clusters, and consequently, so-called “hot spots” can be formed. In order to improve PCB detection limit, 3,3',4,4'-tetrachlorobiphenyl (PCB77) compounds were chemically modified with a – SCH3 (PCB77-SCH3) group. Experimental and numerical analysis of vibrational modes...
20. Polychlorinated biphenyls and their interaction with the environment
Energy Technology Data Exchange (ETDEWEB)
Dickerson, K.S.; Korte, N.E.
1994-05-01
This document is a review of the existing technical literature regarding the physical and biological properties of polychlorinated biphenyls (PCBs) and their interaction with the environment. It is intended to be used when evaluating PCB-contaminated soil and the effects of specific environmental conditions on PCB degradation. PCBs are a class of chlorinated aromatic compounds with 209 possible structural arrangements. The composition of PCBs in the environment changes over time due to various physiochemical and biological properties and processes: vapor pressure, solubility, octanol-water partitioning, adsorption, and biodegradation. As the number of chlorine atoms increases, both vapor pressure and water solubility decrease, while adsorption and the octanol-water partitioning coefficient increase. Dechlorination of PCBs occurs primarily through aerobic and anaerobic microbial degradation. Aerobic bacteria preferentially dechlorinate less-chlorinated PCBs, while anaerobic bacteria preferentially dechlorinate more highly chlorinated PCBs. The less-chlorinated PCB congeners are less persistent in the environment due to volatilization, solubility, and aerobic biodegradation, while the more-chlorinated PCBs are more persistent in the environment due to adsorption. The composition of an original PCB mixture in the environment can be expected to change due to a combination of processes described above. Any attempt to determine the source of PCBs or Aroclors identified in an environment sample must be approached with caution to avoid inaccurate conclusions.
1. Design, Synthesis, and Herbicidal Activity of Pyrimidine-Biphenyl Hybrids as Novel Acetohydroxyacid Synthase Inhibitors.
Science.gov (United States)
Li, Ke-Jian; Qu, Ren-Yu; Liu, Yu-Chao; Yang, Jing-Fang; Devendar, Ponnam; Chen, Qiong; Niu, Cong-Wei; Xi, Zhen; Yang, Guang-Fu
2018-04-18
The issue of weed resistance to acetohydroxyacid synthase (EC 2.2.1.6, AHAS) inhibitors has become one of the largest obstacles for the application of this class of herbicides. In a continuing effort to discover novel AHAS inhibitors to overcome weed resistance, a series of pyrimidine-biphenyl hybrids (4aa-bb and 5aa-ah) were designed and synthesized via a scaffold hopping strategy. Among these derivatives, compounds 4aa ( K i = 0.09 μM) and 4bb ( K i = 0.02 μM) displayed higher inhibitory activities against Arabidopsis thaliana AHAS than those of the controls bispyribac ( K i = 0.54 μM) and flumetsulam ( K i = 0.38 μM). Remarkably, compounds 4aa, 4bb, 5ah, and 5ag exhibited excellent postemergence herbicidal activity and a broad spectrum of weed control at application rates of 37.5-150 g of active ingredient (ai)/ha. Furthermore, 4aa and 4bb showed higher herbicidal activity against AHAS inhibitor-resistant Descurainia sophia, Ammannia arenaria, and the corresponding sensitive weeds than that of bispyribac at 0.94-0.235 g ai/ha. Therefore, the pyrimidine-biphenyl motif and lead compounds 4aa and 4bb have great potential for the discovery of novel AHAS inhibitors to combat AHAS-inhibiting herbicide-resistant weeds.
2. Degradation of polychlorinated biphenyls using mesoporous iron-based spinels
Energy Technology Data Exchange (ETDEWEB)
Huang, Linyan; Su, Guijin, E-mail: gjsu@rcees.ac.cn; Zhang, Aiqian; Shi, Yali; Xia, Chaobo; Lu, Huijie; Li, Liewu; Liu, Sha; Zheng, Minghui
2013-10-15
Highlights: • The NiFe{sub 2}O{sub 4} had the highest activity in degradation of CB-209, followed by Fe{sub 3}O{sub 4}. • Hydroxyl species, organic acids, PCBs and chlorobenzenes were identified as products. • Three degradation reactions and one combination reaction competitively occurred. • Hydrodechlorination of CB-209 was more favored over Fe{sub 3}O{sub 4} than NiFe{sub 2}O{sub 4}. • Oxidation reaction of CB-209 was more favored over NiFe{sub 2}O{sub 4} than Fe{sub 3}O{sub 4}. -- Abstract: A series of mesoporous iron-based spinel materials were synthesized to degrade polychlorinated biphenyls (PCBs), with CB-209 being used as a model compound. The materials were characterized by X-ray powder diffraction (XRD), pore structure analysis, and X-ray photoelectron spectroscopy (XPS). A comparison of the dechlorination efficiencies (DEs) of the materials revealed that NiFe{sub 2}O{sub 4} had the highest DE, followed by Fe{sub 3}O{sub 4}. Newly produced polychlorinated biphenyls, chlorinated benzenes, hydroxyl species and organic acids were detected by gas chromatography–mass spectrometry, high performance liquid chromatography–mass spectrometry and ion chromatograph. Identification of the intermediate products indicates that three degradation pathways, hydrodechlorination, the breakage of C-C bridge bond and oxidative reaction, accompanied by one combination reaction, are competitively occurring over the iron-based spinels. The relative amounts of produced three NoCB isomers were illustrated by the C-Cl BDEs of CB-209 at meta-, para- and ortho-positions, and their energy gap between HOMO and LUMO. The consumption of the reactive oxygen species caused by the transformation of Fe{sub 3}O{sub 4} into Fe{sub 2}O{sub 3} in the Fe{sub 3}O{sub 4} reaction system, and the existence of the highly reactive O{sub 2}{sup −}· species in the NiFe{sub 2}O{sub 4} reaction system, could provide a reason why the oxidation reaction was more favored over NiFe{sub 2}O
3. Spatial gradients of polychlorinated biphenyls (PCBs) and organochlorine pesticides
Data.gov (United States)
National Oceanic and Atmospheric Administration, Department of Commerce — Spatial gradients of polychlorinated biphenyls (PCBs) and organochlorine pesticides were examined in the young-of-the-year (YOY) blueÂżsh collected in the vicinity...
4. Bioaccumulation dynamics of polychlorinated biphenyls (PCBs) and organochlorine pesticides
Data.gov (United States)
National Oceanic and Atmospheric Administration, Department of Commerce — Bioaccumulation dynamics of polychlorinated biphenyls (PCBs) and organochlorine pesticides was examined in young-of-the-year bluefish from seven sub-estuaries of New...
5. Crystal structure of 4,4′-bis[3-(piperidin-1-ylprop-1-yn-1-yl]-1,1′-biphenyl
Directory of Open Access Journals (Sweden)
Anqi Walbaum
2017-06-01
Full Text Available The title compound, C28H32N2, (I, is one of a second generation of compounds designed and synthesized based on a very potent and selective α9α10 nicotinic acetylcholine receptor antagonist ZZ161C {1,1′-[[1,1′-biphenyl]-4,4′-diylbis(prop-2-yne-3,1-diyl]bis(3,4-dimethylpyridin-1-ium bromide}, which has shown analgesic effects in a chemotherapy-induced neuropathy animal model. Compound (I was synthesized by the reaction of 4,4′-bis(3-bromoprop-1-yn-1-yl-1,1′-biphenyl with piperidine at room temperature in acetonitrile. The single-crystal used for X-ray analysis was obtained by dissolving (I in a mixture of dichloromethane and methanol, followed by slow evaporation of the solvent. In the crystal of (I, the biphenyl moiety has a twisted conformation, with a dihedral angle of 25.93 (4° between the benzene rings. Both piperidine head groups in (I are in the chair conformation and are oriented so that the N-atom lone pairs of each piperidine group point away from the central biphenyl moiety.
6. Adaptation mechanisms of bacteria during the degradation of polychlorinated biphenyls in the presence of natural and synthetic terpenes as potential degradation inducers
Energy Technology Data Exchange (ETDEWEB)
Zoradova-Murinova, Slavomira; Dudasova, Hana; Lukacova, Lucia; Certik, Milan; Dercova, Katarina [Slovak Univ. of Technology, Bratislava (Slovakia). Inst. of Biotechnology and Food Science; Silharova, Katarina; Vrana, Branislav [Water Research Institute, Bratislava (Slovakia)
2012-06-15
7. NUCLEOTIDE SEQUENCING AND TRANSCRIPTIONAL MAPPING OF THE GENES ENCODING BIPHENYL DIOXYGENASE, A MULTICOM- PONENT POLYCHLORINATED-BIPHENYL-DEGRADING ENZYME IN PSEUDOMONAS STRAIN LB400
Science.gov (United States)
The DNA region encoding biphenyl dioxygenase, the first enzyme in the biphenyl-polychlorinated biphenyl degradation pathway of Pseudomonas species strain LB400, was sequenced. Six open reading frames were identified, four of which are homologous to the components of toluene dioxy...
8. Bis(μ-biphenyl-2,2′-dicarboxylatobis[(2,2′-bipyridinecopper(II
Directory of Open Access Journals (Sweden)
Zhe An
2009-04-01
Full Text Available The title compound, [Cu2(C14H8O42(C10H8N22], was obtained by solvothermal synthesis. The CuII atom is coordinated by one chelating 2,2′-bipyridine ligand and two carboxyl groups from different biphenyl-2,2′-dicarboxylate ligands, leading to a distorted octahedral environment. Each carboxylate group makes one short Cu—O bond [1.9608 (14 and 1.9701 (14 Å] and one longer Cu—O contact [2.4338 (17 and 2.5541 (17 Å] to each CuII atom. The biphenyl-2,2′-dicarboxylate ligands bridge between CuII atoms, forming a dinuclear complex around a crystallographic inversion centre.
9. (Biphenyl-4-yl)methylammonium chlorides: potent anticonvulsants that modulate Na+ currents.
Science.gov (United States)
Lee, Hyosung; Park, Ki Duk; Yang, Xiao-Fang; Dustrude, Erik T; Wilson, Sarah M; Khanna, Rajesh; Kohn, Harold
2013-07-25
We have reported that compounds containing a biaryl linked unit (Ar-X-Ar') modulated Na(+) currents by promoting slow inactivation and fast inactivation processes and by inducing frequency (use)-dependent inhibition of Na(+) currents. These electrophysiological properties have been associated with the mode of action of several antiepileptic drugs. In this study, we demonstrate that the readily accessible (biphenyl-4-yl)methylammonium chlorides (compound class B) exhibited a broad range of anticonvulsant activities in animal models, and in the maximal electroshock seizure test the activity of (3'-trifluoromethoxybiphenyl-4-yl)methylammonium chloride (8) exceeded that of phenobarbital and phenytoin upon oral administration to rats. Electrophysiological studies of 8 using mouse catecholamine A-differentiated cells and rat embryonic cortical neurons confirmed that 8 promoted slow and fast inactivation in both cell types but did not affect the frequency (use)-dependent block of Na(+) currents.
10. Persistent organochlorine residues and toxic evaluation of polychlorinated biphenyls in sharks from the Mediterranean Sea (Italy)
Energy Technology Data Exchange (ETDEWEB)
Storelli, M.M.; Marcotrigiano, G.O. [Bari Univ., Dip. Farmaco-Biologico, Bari (Italy)
2001-07-01
Persistent organochlorines such as polychlorinated biphenyls including coplanar congeners, DDT compounds and HCB were measured in different tissues (muscle, liver and eggs) of two Mediterranean shark species: namely Centrophorus granulosus and Squalus blainvillei. The concentrations of organochlorines in the tissues and organs of both species were in the order DDTs>PCBs>HCB. The highest values of DDTs, PCBs and HCB were found in liver followed by eggs and muscle. Among DDTs the compound found in greatest concentration was p,p -DDE. The PCB profiles were dominated by congeners 138, 153, and 180. The isomers with higher TEQs values were non- and mono-ortho congeners than di-ortho ones in muscle, liver and eggs of both species. Among the non-ortho, PCB 126 was the major contributing individual to the total TEQs in both species. (Author)
11. Consolidated PCBs [polychlorinated biphenyls] improves waste control
International Nuclear Information System (INIS)
Smith, E.
1991-01-01
Consolidation of polychlorinated biphenyl (PCB) wastes is recommended for improving ownership control of wastes, eliminating PCB storage sites, and increasing cost-effectiveness of waste management. In Ontario, sites receiving the waste must be owned by the waste generator and registered as a PCB site. All PCBs must be removed from a site with no contaminated materials or wastes left behind, which requires a thorough site assessment to identify wastes prior to removal, a sampling and analytical scheme if necessary, and an approved plan for site cleanup. If large volumes of PCB-contaminated oil are involved, it may be cost-effective to put oil from several sites into bulk tanks and thus avoid the need to handle and decontaminate a large number of drums. With low volumes of oil, it may be possible to move the waste to another site where mobile PCB destruction is taking place. It also may be possible to get approval to blend high-level PCB liquids with mineral oil to reduce the PCB concentration to a level where chemical decontamination is allowed. For large volumes of high-level PCB wastes, consolidation will be necessary simply because of the high costs of mobilizing an incinerator and the requirement for public hearings for each incineration project. To make such a project cost-effective, PCB wastes will have to be concentrated from a large geographic area. 1 fig
12. New technologies for PCB [polychlorinated biphenyl] decontamination
International Nuclear Information System (INIS)
Webber, I.
1993-01-01
Polychlorinated biphenyls (PCB) were mixed with chlorobenzenes to reduce viscosity and provide for both electrical insulation and convective heat transfers. These mixtures were known as askarels, and ca 99.8% of PCBs used in electrical applications are contained in askarel-filled transformers and capacitors. It is estimated that there are ca 180 million gal of PCB-contaminated oil distributed through over 3 million transformers in the USA. Technology used for decontaminating these transformers depends on the concentration of the PCB contamination. At low PCB concentrations of up to ca 2,000 ppM, chemical methods can be used; at higher concentrations, alternative disposal options become more attractive. For chemical treatment, a small mobile unit using quick-reacting reagents has been developed for on-site decontamination. For highly contaminated transformers, retrofilling is very attractive since the owner's liability is minimized at minimum cost. Conventional flush/drain procedures have such drawbacks as the inability to remove oil trapped in windings and the leaching of trapped PCBs back into the uncontaminated retrofill oil over time. A new process has been developed to solve the leaching problem and to decontaminate the drained askarel at room temperature using a catalyst. An alternative disposal strategy involves dismantling the transformer carcass, incinerating non-recyclable materials, and cleaning the metals and wire with solvent. 8 figs
13. Polychlorinated biphenyls in Spanish adults: Determinants of serum concentrations
Energy Technology Data Exchange (ETDEWEB)
Agudo, Antonio, E-mail: a.agudo@iconcologia.net [Unit of Nutrition, Environment, and Cancer, Cancer Epidemiology Research Program, Catalan Institute of Oncology (ICO), IDIBELL, Av. Gran Via no 199-203, 08907 L' Hospitalet de Llobregat (Spain); Goni, Fernando [Laboratorio de Salud Publica de Guipuzcoa, 20013 San Sebastian (Spain); CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Etxeandia, Arsenio [Laboratorio de Salud Publica de Vizcaya, 48010 Bilbao (Spain); Vives, Asuncion [Laboratorio Unificado Donostia, Hospital N. S. Aranzazu, 20014 San Sebastian (Spain); Millan, Esmeralda [Departamento de Quimica Aplicada, Universidad del Pais Vasco, Facultad de Quimica, 20080 San Sebastian (Spain); Lopez, Raul [CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Amiano, Pilar [CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Direccion de Salud de Guipuzcoa, 20013 San Sebastian (Spain); Ardanaz, Eva; Barricarte, Aurelio [CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Instituto de Salud Publica de Navarra, 31003 Pamplona (Spain); Dolores Chirlaque, M. [CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Consejeria de Sanidad, 3008 Murcia (Spain); Dorronsoro, Miren [CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Direccion de Salud de Guipuzcoa, 20013 San Sebastian (Spain); Jakszyn, Paula [Unit of Nutrition, Environment, and Cancer, Cancer Epidemiology Research Program, Catalan Institute of Oncology (ICO), IDIBELL, Av. Gran Via no 199-203, 08907 L' Hospitalet de Llobregat (Spain); Larranaga, Nerea [CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Direccion de Salud de Guipuzcoa, 20013 San Sebastian (Spain); Martinez, Carmen [CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Escuela Andaluza de Salud Publica, 18080 Granada (Spain); Navarro, Carmen [CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Consejeria de Sanidad, 3008 Murcia (Spain); Rodriguez, Laudina [Consejeria de Salud y Servicios Sanitarios de Asturias, 33001 Oviedo (Spain); and others
2009-07-15
Background: Polychlorinated biphenyls (PCBs) are persistent compounds that may pose an environmental hazard to humans, food being the main source of exposure for the general population. Objective: To measure the serum concentrations of the main PCBs in subjects from the general population in Spain, and to assess potential determinants of such concentrations. Methods: Serum was obtained from blood samples of 953 subjects aged 35-64 years, residents in five Spanish regions (three from the North and two from the South), randomly selected from the EPIC-Spain cohort. Blood collection took place during 1992-1996 and four PCB congeners (118, 138, 153 and 180) were determined by means of gas chromatography with electron-capture detection (GC-ECD). Results: The concentration of total PCBs was 459 ng/g lipids (or 3.1 {mu}g/l); the corresponding figures for PCB 153 were 186 ng/g lipids and 1.25 {mu}g/l. Men had higher values than women, PCB levels increased with age, and serum concentration of PCBs was higher in northern regions. Body mass index (BMI) was inversely related to PCB concentrations, and fish intake was the dietary factor showing the greatest association with serum PCBs. The pattern described was similar for each congener separately. Conclusions: We found concentrations similar to those reported in European countries where blood collection was carried during the same period. Regional differences within Spain are not fully explained by anthropometric or dietary factors. The inverse association with BMI suggests that in the mid-1990s there was still ongoing or recent exposure to PCBs in Spain.
14. Polychlorinated biphenyls in Spanish adults: Determinants of serum concentrations
International Nuclear Information System (INIS)
Agudo, Antonio; Goni, Fernando; Etxeandia, Arsenio; Vives, Asuncion; Millan, Esmeralda; Lopez, Raul; Amiano, Pilar; Ardanaz, Eva; Barricarte, Aurelio; Dolores Chirlaque, M.; Dorronsoro, Miren; Jakszyn, Paula; Larranaga, Nerea; Martinez, Carmen; Navarro, Carmen; Rodriguez, Laudina
2009-01-01
Background: Polychlorinated biphenyls (PCBs) are persistent compounds that may pose an environmental hazard to humans, food being the main source of exposure for the general population. Objective: To measure the serum concentrations of the main PCBs in subjects from the general population in Spain, and to assess potential determinants of such concentrations. Methods: Serum was obtained from blood samples of 953 subjects aged 35-64 years, residents in five Spanish regions (three from the North and two from the South), randomly selected from the EPIC-Spain cohort. Blood collection took place during 1992-1996 and four PCB congeners (118, 138, 153 and 180) were determined by means of gas chromatography with electron-capture detection (GC-ECD). Results: The concentration of total PCBs was 459 ng/g lipids (or 3.1 μg/l); the corresponding figures for PCB 153 were 186 ng/g lipids and 1.25 μg/l. Men had higher values than women, PCB levels increased with age, and serum concentration of PCBs was higher in northern regions. Body mass index (BMI) was inversely related to PCB concentrations, and fish intake was the dietary factor showing the greatest association with serum PCBs. The pattern described was similar for each congener separately. Conclusions: We found concentrations similar to those reported in European countries where blood collection was carried during the same period. Regional differences within Spain are not fully explained by anthropometric or dietary factors. The inverse association with BMI suggests that in the mid-1990s there was still ongoing or recent exposure to PCBs in Spain.
15. Dechlorination of polychlorinated biphenyls by iron and its oxides.
Science.gov (United States)
Sun, Yifei; Liu, Xiaoyuan; Kainuma, Masashi; Wang, Wei; Takaoka, Masaki; Takeda, Nobuo
2015-10-01
The decomposition efficiency of polychlorinated biphenyls (PCBs) was determined using elemental iron (Fe) and three iron (hydr)oxides, i.e., α-Fe2O3, Fe3O4, and α-FeOOH, as catalysts. The experiments were performed using four distinct PCB congeners (PCB-209, PCB-153, and the coplanar PCB-167 and PCB-77) at temperatures ranging from 180 °C to 380 °C and under an inert, oxidizing or reducing atmosphere composed of N2, N2+O2, or N2+H2. From these three options N2 showed to provide the best reaction atmosphere. Among the iron compounds tested, Fe3O4 showed the highest activity for decomposing PCBs. The decomposition efficiencies of PCB-209, PCB-167, PCB-153, and PCB-77 by Fe3O4 in an N2 atmosphere at 230 °C were 88.5%, 82.5%, 69.9%, and 66.4%, respectively. Other inorganic chlorine (Cl) products which were measured by the amount of inorganic Cl ions represented 82.5% and 76.1% of the reaction products, showing that ring cleavage of PCBs was the main elimination process. Moreover, the dechlorination did not require a particular hydrogen donor. We used X-ray photoelectron spectroscopy to analyze the elemental distribution at the catalyst's surface. The O/Fe ratio influenced upon the decomposition efficiency of PCBs: the lower this ratio, the higher the decomposition efficiency. X-ray absorption near edge structure spectra showed that α-Fe2O3 effectively worked as a catalyst, while Fe3O4 and α-FeOOH were consumed as reactants, as their final state is different from their initial state. Finally, a decomposition pathway was postulated in which the Cl atoms in ortho-positions were more difficult to eliminate than those in the para- or meta-positions. Copyright © 2015 Elsevier Ltd. All rights reserved.
16. SYNTHESIS AND HEMOLYTIC PROPERTIES OF DERIVATIVES OF 4,4'-DIHYDROXYBIPHENYL – 2,2'-[BIPHENYL-4,4'- DIYLBIS(OXY]BIS[N-(METHYLAMINOALKILACETAMIDES
Directory of Open Access Journals (Sweden)
S. O. Zanoza
2016-04-01
Full Text Available The purpose of this work was synthesis of 4,4’-dihydroxybiphenyl derivatives, namely 2,2’-[biphenyl-4,4’-diylbis(oxy]bis[N-(2-aminoalkylacetamide], study of their hemolytic properties and the effect of the side chain structure on hemolytic properties. 2,2’-[Biphenyl-4,4’-diylbis(oxy]diacetic acid was synthesized by alkylation of 4,4’-dihydroxybiphenyl with methylbromoacetate, followed by alkaline hydrolysis. Chloroanhydride was obtained by treatment of this acid with thionyl chloride. 2,2’-[Biphenyl-4,4’-diylbis(oxy] bis-[N-(2-aminoalkylacetamides] were synthesized in the biphasic media (dichloromethane/ aqueous sodium carbonate. Structures of synthesized compounds were proved by mass-spectrometryand 1Н NMR. Hemolytic properties were studied using healthy donors’ erythrocytes 0(I/Rh+. The absence of hemolytic properties for obtained compounds was shown, unlike similar 4,4’-aminoalkoxybiphenyls for which a significant hemolysis was shown. Thus, replacement of the ethylene group with amide group in the side chain of 4,4’-bissubstituted biphenyls significantly reduces hemolytic properties.
17. Ability of bacterial biphenyl dioxygenases from Burkholderia sp. LB400 and Comamonas testosteroni B-356 to catalyse oxygenation of ortho-hydroxychlorobiphenyls formed from PCBs by plants
International Nuclear Information System (INIS)
Francova, K.; Mackova, M.; Macek, T.; Sylvestre, M.
2004-01-01
Bacterial dioxygenases are useful in breakdown of PCB products associated with plants. - Capacity of enzymes of the biphenyl/chlorobiphenyl pathway, especially biphenyl dioxygenase (BPDO) of two polychlorinated biphenyls (PCB) degrading bacteria, Burkholderia sp. LB400 and Comamonas testosteroni B-356, to metabolize ortho-substituted hydroxybiphenyls was tested.,These compounds found among plant products of PCB metabolism, are carrying chlorine atoms on the hydroxyl-substituted ring. The abilities of His-tagged purified LB400 and B-356 BPDOs to catalyze the oxygenation of 2-hydroxy-3-chlorobiphenyl, 2-hydroxy-5-chlorobiphenyl and 2-hydroxy-3,5-dichlorobiphenyl were compared. Both enzyme preparations catalyzed the hydroxylation of the three chloro-hydroxybiphenyls on the non-substituted ring. Neither LB400 BPDO nor B-356 BPDO oxygenated the substituted ring of the ortho-hydroxylated biphenyl. The fact that metabolites generated by both enzymes were identical for all three hydroxychlorobiphenyls tested; exclude any other mode of attack of these compounds by LB400 BPDOs than the ortho-meta oxygenation
18. Identification of a novel dimethoxylated polybrominated biphenyl bioaccumulating in marine mammals
Energy Technology Data Exchange (ETDEWEB)
Marsh, G.; Athanasiadou, M.; Bergman, Aa.; Athanassiadis, I. [Department of Environmental Chemistry, Stockholm (Sweden); Endo, Tetsuya [Health Sciences Univ. of Hokkaido (Japan). Fac. of Pharmaceutical Sciences; Haraguchi, Koichi [Daiichi College of Pharmaceutical Sciences, Fukuoka (Japan)
2004-09-15
The screening of persistent halogenated organic pollutants has in recent years ended up with findings of numerous compounds being natural products. These compounds have preferably been reported from the marine environment and comprise, several hydroxylated and methoxylated polybrominated diphenyl ethers (OH-PBDEs and MeO-PBDEs) including monochlorinated ditto, a dimethoxylated polybrominated diphenyl ether i.e. 2',6-dimethoxy-2,3',4,5'-tetrabromodiphenyl ether, four halogenated dimethylated bipyrroles (HDBPs) with a 2,2'-bipyrrole backbone, a heptachlorinated 1,2'-bipyrrole i.e. heptachloro-1'-methyl-1,2'-bipyrrole (Q1)6 and a halogenated monoterpene holding two bromine and three chlorine atoms. We have taken interest in an organobrominated compound with an unknown structure but with a molecule ion of m/z = 526 and a four bromine isotope pattern according to mass spectrometry (MS), detected in marine mammal samples of which the majority were collected from Japanese coastal waters. This compound has recently been reported from several marine mammals collected on the Southern hemisphere, but neither the chemical structure nor the type of substance group were established. We here report the structure of this organobrominated compound, a dimethoxylated polybrominated biphenyl, which likely is of natural origin. The identification was done by the comparison of relative retention time (RRT) on two GC columns with different polarities and by comparing mass spectra from three different ionization techniques i.e. PICI, ECNI and EI, of the unknown compound from the samples with an authentic reference compound. Levels of the novel dimethoxylated polybrominated biphenyl are reported as well as the levels (for comparison) of some other known polybrominated compounds, both brominated flame retardants (BFRs) and natural products i.e. BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, 1,2,5,6,9,10- hexabromocyclododecane (HBCDD), 6-MeO-BDE-47, 2
19. The associations between the environmental exposure to polychlorinated biphenyls (PCBs) and breast cancer risk and progression
Institute of Scientific and Technical Information of China (English)
2010-01-01
Polychlorinated biphenyls(PCBs) are chlorinated biphenyl compounds with wide applications in the industry.In spite of a ban on their production in the late 1970s,PCBs,as a group of POPs,are still persistent and widely spread in the environment,posing potential threats to human health.The role of PCBs as etiologic agents for breast cancer has been intensively explored in a variety of in vivo,animal and epidemiologic studies.Initial investigations indicated higher levels of PCBs in mammary tissues or sera corresponded to the occurrence of breast cancer,but later studies showed no positive association between PCB exposure and breast cancer development.More recent data suggested that the CYP1A1 m2 polymorphisms might add increased risk to the etiology of breast cancer in women with environmental exposure to PCBs.PCBs are implicated in advancing breast cancer progression,and our unpublished data reveals that PCBs activate the ROCK signaling to enhance breast cancer metastasis.Therefore,the correlation between PCB exposure and breast cancer risk warrants further careful investigations.
20. Enhancing effect of spawning on elimination of a persistent polychlorinated biphenyl from female yellow perch
International Nuclear Information System (INIS)
Vodicnik, M.J.; Peterson, R.E.
1985-01-01
Distribution and elimination of 2,5,2',5'-tetrachloro[14C]biphenyl (4-CB) were studied for 6 months after exposing sexually mature female yellow perch to the compound in water and transferring them to flowing 4-CB-free water. Perch that were exposed in January spawned in May, and the study was terminated in June. During the first 41/2 months after exposure, the t1/2 for whole-body elimination was 22 weeks, primarily by elimination of 4-CB from the viscera and carcass. During spawning, enhanced elimination (t1/2 less than 0.7 weeks) was due to the voiding of eggs containing 4-CB. After spawning, whole-body elimination returned to a slower rate (t1/2 = 16.3 weeks). Prior to the enhancement in 4-CB elimination rate during spawning, there was a redistribution of 4-CB residues within the body of the perch which was characterized by a transfer of 4-CB residues from primarily the carcass and viscera to eggs. Two weeks after exposure, 30% of the initial 4-CB body burden was distributed to the eggs, whereas just prior to spawning, about 50% was present in this tissue. These findings demonstrate that egg maturation and spawning result in a significant reduction in the body burden of a persistent polychlorinated biphenyl in a lean-fish species
1. Hydroxy and methylsulfone metabolites of polychlorinated biphenyls in the human blood and tissues
Energy Technology Data Exchange (ETDEWEB)
Masuda, Yoshito; Haraguchi, Koichi [Daiichi College of Pharmaceutical Sciences, Fukuoka (Japan)
2004-09-15
Polychlorinated biphenyls (PCBs) are a group of chlorinated compounds which have polluted the global environment, persistently retained in wildlife and humans, and eventually affected the human health. PCBs are biotransformed to mainly hydroxy (HO-) and methylsulfone (MeSO{sub 2}-) metabolites in the animal and human tissues. About ten thousands of chemical and biological researches on PCBs, HOPCBs and MeSO{sub 2}-PCBs have been reported and reviewed so far. Letcher et al. cleverly reviewed the HO-PCBs and MeSO2-PCBs in 2000. We review the contamination of HO-PCBs and MeSO{sub 2}-PCBs in human tissues and their possible effects to human health. Different positional numberings of Cl-, HO- and MeSO{sub 2}- on biphenyl rings were used by different authors. Then, nomenclature of PCB metabolite was assessed by Maervoet et al. and they suggested to use the IUPAC chemical name and number of parent PCB congener with the subsequent assignment of the phenyl ring position number of the HO- or MeSO{sub 2}- substituent number afterward.
2. OXIDATION OF POLYCHLORINATED BIPHENYLS BY PSEUDOMONAS SP. STRAIN LB400 AND PSEUDOMONAS PSEUDOALCALIGENES KF707
Science.gov (United States)
Biphenyl-grown cells and cell extracts prepared from biphenyl-grown cells of Pseudomonas sp. strain LB400 oxidize a much wider range of chlorinated biphenyls than do analogous preparations from Pseudomonas pseudoalcaligenes KF707. These results are attributed to differences in th...
3. OXIDATION OF BIPHENYL BY A MULTICOMPONENT ENZYME SYSTEM FROM PSEUDOMONAS SP. STRAIN LB400
Science.gov (United States)
Pseudomonas sp. strain LB400 grows on biphenyl as the sole carbon and energy source. This organism also cooxidizes several chlorinated biphenyl congeners. Biphenyl dioxygenase activity in cell extract required addition of NAD(P)H as an electron donor for the conversion of bipheny...
4. Exposure Monitoring and Risk Assessment of Biphenyl in the Workplace
Directory of Open Access Journals (Sweden)
Hyeon-Yeong Kim
2015-05-01
Full Text Available This study was performed to assess exposure to and the risk caused by biphenyl in the workplace. Biphenyl is widely used as a heat transfer medium and as an emulsifier and polish in industry. Vapor or high levels of dust inhalation and dermal exposure to biphenyl can cause eye inflammation, irritation of respiratory organs, and permanent lesions in the liver and nervous system. In this study, the workplace environment concentrations were assessed as central tendency exposure and reasonable maximum exposure and were shown to be 0.03 and 0.12 mg/m3, respectively. In addition, the carcinogenic risk of biphenyl as determined by risk assessment was 0.14 × 10−4 (central tendency exposure and 0.56 × 10−4 (reasonable maximum exposure, which is below the acceptable risk value of 1.0 × 10−4. Furthermore, the central tendency exposure and reasonable maximum exposure hazard quotients were 0.01 and 0.06 for oral toxicity, 0.05 and 0.23 for inhalation toxicity, and 0.08 and 0.39 for reproduction toxicity, respectively, which are all lower than the acceptable hazard quotient of 1.0. Therefore, exposure to biphenyl was found to be safe in current workplace environments. Because occupational exposure limits are based on socioeconomic assessment, they are generally higher than true values seen in toxicity experiments. Based on the results of exposure monitoring of biphenyl, the current occupational exposure limits in Korea could be reviewed.
5. Exposure monitoring and risk assessment of biphenyl in the workplace.
Science.gov (United States)
Kim, Hyeon-Yeong; Shin, Sae-Mi; Ham, Miran; Lim, Cheol-Hong; Byeon, Sang-Hoon
2015-05-13
This study was performed to assess exposure to and the risk caused by biphenyl in the workplace. Biphenyl is widely used as a heat transfer medium and as an emulsifier and polish in industry. Vapor or high levels of dust inhalation and dermal exposure to biphenyl can cause eye inflammation, irritation of respiratory organs, and permanent lesions in the liver and nervous system. In this study, the workplace environment concentrations were assessed as central tendency exposure and reasonable maximum exposure and were shown to be 0.03 and 0.12 mg/m³, respectively. In addition, the carcinogenic risk of biphenyl as determined by risk assessment was 0.14 × 10⁻⁴ (central tendency exposure) and 0.56 × 10⁻⁴ (reasonable maximum exposure), which is below the acceptable risk value of 1.0 × 10⁻⁴. Furthermore, the central tendency exposure and reasonable maximum exposure hazard quotients were 0.01 and 0.06 for oral toxicity, 0.05 and 0.23 for inhalation toxicity, and 0.08 and 0.39 for reproduction toxicity, respectively, which are all lower than the acceptable hazard quotient of 1.0. Therefore, exposure to biphenyl was found to be safe in current workplace environments. Because occupational exposure limits are based on socioeconomic assessment, they are generally higher than true values seen in toxicity experiments. Based on the results of exposure monitoring of biphenyl, the current occupational exposure limits in Korea could be reviewed.
6. Polychlorinated Biphenyls (PCB) Residue Effects Database
Data.gov (United States)
U.S. Environmental Protection Agency — The PCB Residue Effects (PCBRes) Database was developed to assist scientists and risk assessors in correlating PCB and dioxin-like compound residues with toxic...
7. Substituted N-(biphenyl-4'-yl)methyl (R)-2-acetamido-3-methoxypropionamides: potent anticonvulsants that affect frequency (use) dependence and slow inactivation of sodium channels.
Science.gov (United States)
Lee, Hyosung; Park, Ki Duk; Torregrosa, Robert; Yang, Xiao-Fang; Dustrude, Erik T; Wang, Yuying; Wilson, Sarah M; Barbosa, Cindy; Xiao, Yucheng; Cummins, Theodore R; Khanna, Rajesh; Kohn, Harold
2014-07-24
We prepared 13 derivatives of N-(biphenyl-4'-yl)methyl (R)-2-acetamido-3-methoxypropionamide that differed in type and placement of a R-substituent in the terminal aryl unit. We demonstrated that the R-substituent impacted the compound's whole animal and cellular pharmacological activities. In rodents, select compounds exhibited excellent anticonvulsant activities and protective indices (PI=TD50/ED50) that compared favorably with clinical antiseizure drugs. Compounds with a polar, aprotic R-substituent potently promoted Na+ channel slow inactivation and displayed frequency (use) inhibition of Na+ currents at low micromolar concentrations. The possible advantage of affecting these two pathways to decrease neurological hyperexcitability is discussed.
8. Persistent organochlorine compounds in peregrine falcon (Falco peregrinus) eggs from South Greenland: Levels and temporal changes between 1986 and 2003
DEFF Research Database (Denmark)
Vorkamp, Katrin; Thomsen, Marianne; Møller, Søren
2009-01-01
Thirty-seven addled peregrine falcon eggs collected in South Greenland between 1986 and 2003 wereanalysed for their content of the organochlorine compounds polychlorinated biphenyls (PCBs), dichlorodiphenyltricloroethane (DDT) and its degradation products, hexachlorocyclohexane (HCH) isomers andh...
9. Polychlorinated biphenyl sources, environmental levels, and exposures in school buildings
Science.gov (United States)
Background: Building materials and components containing polychlorinated biphenyls (PCBs) were used in some U.S. school buildings until the late 1970s and may be present today. There is limited information on source factors and occupant exposures. Methods: Analysis of PCBs in mat...
10. Congener profiles of polychlorinated biphenyls and the effect on ...
African Journals Online (AJOL)
This study investigated the effect of freshwater as a point source of PCBs contributing to a marine outfall region. Inflowing and outflowing water from the North End Lake, Port Elizabeth, was collected to determine the contamination levels of polychlorinated biphenyls (PCBs). Mussels at the outflow to the sea were also ...
11. Metabolic Pathways of Polychlorinated Biphenyls Degradation by Pseudomonas sp. 2
Czech Academy of Sciences Publication Activity Database
Komancová, M.; Jurčová, Irena; Kochánková, L.; Burkhard, J.
2003-01-01
Roč. 50, č. 4 (2003), s. 537ů543 ISSN 0045-6535 Institutional research plan: CEZ:AV0Z4072921 Keywords : polychlorinated biphenyls * biodegradation * aerobic bacteria Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.904, year: 2003
12. Polychlorinated biphenyl exposure and deiodinase activity in young infants
NARCIS (Netherlands)
Soechitram, Shalini D.; Berghuis, Sietske A.; Visser, Theo J.; Sauer, Pieter J. J.
2017-01-01
Background: Several studies have shown effects of polychlorinated biphenyls (PCBs) on serum thyroid hormone levels in pregnant woman and their infants, while other studies did not find such effects. How PCBs might affect thyroid hormone metabolism, is still unclear. Potential mechanisms are direct
13. Attenuation of polychlorinated biphenyl sorption to charcoal by humic acids
NARCIS (Netherlands)
Koelmans, A.A.; Meulman, B.; Meijer, T.; Jonker, M.T.O.
2009-01-01
Strong sorption to black carbon may limit the environmental risks of organic pollutants, but interactions with cosorbing humic acid (HA) may interfere. We studied the attenuative effect of HA additions on the sorption of polychlorinated biphenyls (PCBs) to a charcoal. "Intrinsic" sorption to
14. Transgenic plants to improve rhizoremediation of polychlorinated biphenyls (PCBs)
Czech Academy of Sciences Publication Activity Database
Sylvestre, M.; Macek, Tomáš; Macková, Martina
2009-01-01
Roč. 20, č. 2 (2009), s. 242-247 ISSN 0958-1669 R&D Projects: GA MŠk 1M06030 Institutional research plan: CEZ:AV0Z40550506 Keywords : bacterial dioxygenases * GM- plants * polychlorinated biphenyls * rhizoremediation Subject RIV: EI - Biotechnology ; Bionics Impact factor: 7.820, year: 2009
15. Photochemical of Polychlorinated biphenyl by the photolysis and ...
African Journals Online (AJOL)
pressure mercury lamp. The whole Lamp was immersed in a reactor thermostat controlling the temperature at 32 ± 2 °C. The Polychlorinated biphenyls (PCBs) were analyzed by GC/ECD. The degradation of PCBs in terms of one, two and three lamp ...
16. Synthesis and characterization of tissue-retainable methylsulfonyl polychlorinated biphenyl isomers
International Nuclear Information System (INIS)
Haraguchi, K.; Kuroki, H.; Masuda, Y.
1987-01-01
Eighty-six positional isomers of methylsulfonyl polychlorinated biphenyls (MSF-PCBs) have been synthesized by three synthetic routes: (1) the diazo coupling reaction of 3-(methylsulfonyl)chloroaniline with chlorobenzene; (2) nucleophilic substitution of PCB with methanethiolate and successive oxidation of the corresponding methyl sulfide; (3) the diazo coupling reaction of chloroaniline with chlorothioanisole and successive oxidation of the methyl sulfide. Pure isomers were characterized by their proton magnetic resonance and mass spectra and used to unambiguously identify the MSF metabolites retained in human tissues by using high-resolution capillary gas chromatography (GC). The GC analysis showed that 40 MSF derivatives were positively identified in the tissue of a patient with Yusho on the basis of comparisons of their GC retention data with those of the standard compounds
17. Polychlorinated biphenyl concentrations in adipose tissue and abdominal obesity in the elderly
DEFF Research Database (Denmark)
Bräuner, Elvira; Raaschou-Nielsen, Ole; Andersen, Zorana
2013-01-01
Obesity prevalence has more than doubled globally within the last 30 years. Obesity affects quality of life as well as impacts the risks and prognosis for a number of serious diseases. Established causes include a high calorie diet combined with a sedentary lifestyle and possibly the widespread...... cessation of smoking, but these do not fully explain the epidemic. Polychlorinated biphenyl congeners (PCBs) are endocrine-disrupting chemicals and evidence from animal experiments suggests an association with obesity development. Our knowledge of the effects of these compounds on weight gain in humans...... is limited. Our objective was to investigate the association between exposure to PCBs experienced by a general Danish population and development of obesity. We randomly selected 204 persons (113 obese and 91 overweight), aged ≥ 50 years, from a prospective Danish cohort of 57,053 persons and examined ten...
18. Di-tert-butyl 2,2′-(biphenyl-2,2′-diyldioxydiacetate
Directory of Open Access Journals (Sweden)
Qamar Ali
2008-08-01
Full Text Available The title compound, C24H30O6, does not exhibit π–π interactions due to the steric effect of the bulky tert-butyl groups present in the molecule. The presence of these groups at the 2 and 2′ positions hinders the free motion of the benzene rings relative to each other, causing them to adopt an antiperiplanar arrangement. The benzene rings are twisted by just under 50.96 (17° with respect to each other. The carbonyl groups within the molecule are directed in different directions, one towards the biphenyl group and the other away from it. The molecules are linked together by C=O...H—C hydrogen bonds.
19. Organochlorine Pesticides (OCs) and Polychlorinated Biphenyls (PCBs) in Tilapia zillii from Lake El-Manzala, Egypt
International Nuclear Information System (INIS)
El-Greisy, Zeinab Abdalbagi; Abdallah, A. Mohamed Ali
2005-01-01
A fresh water fish species, (Tilapia zillii) from Lake El-Manzala was analyzed for concentrations of several Organochlorine pesticides (OCs) and Polychlorine piphenyl's (PCBs) in liver, gonads, mesenteric fat, flesh and the digestive tract in mature fish during the breeding season. Polychlorinated piphenyls (PCBs) and Organochloripe pesticides (OCs) were calculated in (ng/g) dry weight (dw) in homogenized samples. The obtained results revealed differences in lipid content between these different organs. The females showed higher lipid content than males. There was significant positive correlation the lipid content and organochlorines and polychlorinated biphenyls (PCBs). The results come concomitant with the lipophilicity of studied compounds. However, the recoded concentration of these studied pollutants still does not exceed international hazardous levels. (author)
20. 2-(Biphenyl-4-ylacetic acid (felbinac
Directory of Open Access Journals (Sweden)
Lynne S. Taylor
2010-10-01
Full Text Available The structure of the title compound, C14H12O2, displays the expected intermolecular hydrogen bonding of the carboxylic acid groups, forming dimers. The dihedral angle between the two aromatic rings is 27.01 (7°.
1. The occurrence and significance of polychlorinated biphenyls in the environment
Science.gov (United States)
Dustman, E.H.; Stickel, L.F.; Blus, L.J.; Reichel, W.L.; Wiemeyer, Stanley N.
1971-01-01
SUMMARY: Polychlorinated biphenyls constitute a group of chlorine-bearing compounds of industrial origin that have permeated the natural environment throughout the world. Their chemical structure resembles that of some of the organochlorine pesticides. They are troublesome interferences in gas chromatographic analysis of these pesticides. Although methods have been developed to overcome analytical problems, measurements of quantity still are only approximate. Special studies in the United States, Netherlands, and Great Britain have traced PCB's to industrial effluent, but other possible sources have not been followed. Their use in paints, cartons, and insulating fluids suggests that environmental pollution may be from many different sources. PCB's are present in fish and wildlife in many countries of the world. Quantities are higher in animals living near industrial areas. PCB's build up in biological food chains with increases of tens to thousands of times from lower to higher organisms. Experimental studies have shown that PCB's have a toxicity to mallards, pheasants, bobwhite quail, coturnix quail, red-winged blackbirds, starlings, cowbirds, and grackles that is of the same order as the toxicity of DDE to these species. Overt signs of poisoning also are similar to those caused by compounds of the DDT group. Toxic effects of DDE and Aroclor 1254 to coturnix chicks were additive, but not synergistic. PCB's containing higher percentages of chlorine are more toxic to birds than those containing lower percentages. PCB's of foreign manufacture contained contaminants to an extent that greatly increased their toxicity Aroclor 1242. Statistical evaluations of the role that different chemicals may play in thinning of eggshells of brown pelicans show that DDE residues correlate better with shell thinning than do residues of dieldrin or PCB's. Studies of the effects of PCB's in the environment are as yet insufficient for well-rounded conclusions. The evidence available
2. Chemometric comparison of polychlorinated biphenyl residues and toxicologically active polychlorinated biphenyl congeners in the eggs of Forster's Terns (Sterna fosteri)
Science.gov (United States)
Schwartz, Ted R.; Stalling, David L.
1991-01-01
The separation and characterization of complex mixtures of polychlorinated biphenyls (PCBs) is approached from the perspective of a problem in chemometrics. A technique for quantitative determination of PCB congeners is described as well as an enrichment technique designed to isolate only those congener residues which induce mixed aryl hydrocarbon hydroxylase enzyme activity. A congener-specific procedure is utilized for the determination of PCBs in whichn-alkyl trichloroacetates are used as retention index marker compounds. Retention indices are reproducible in the range of ±0.05 to ±0.7 depending on the specific congener. A laboratory data base system developed to aid in the editing and quantitation of data generated from capillary gas chromatography was employed to quantitate chromatographic data. Data base management was provided by computer programs written in VAX-DSM (Digital Standard MUMPS) for the VAX-DEC (Digital Equipment Corp.) family of computers.In the chemometric evaluation of these complex chromatographic profiles, data are viewed from a single analysis as a point in multi-dimensional space. Principal Components Analysis was used to obtain a representation of the data in a lower dimensional space. Two-and three-dimensional proections based on sample scores from the principal components models were used to visualize the behavior of Aroclor® mixtures. These models can be used to determine if new sample profiles may be represented by Aroclor profiles. Concentrations of individual congeners of a given chlorine substitution may be summed to form homologue concentration. However, the use of homologue concentrations in classification studies with environmental samples can lead to erroneous conclusions about sample similarity. Chemometric applications are discussed for evaluation of Aroclor mixture analysis and compositional description of environmental residues of PCBs in eggs of Forster's terns (Sterna fosteri) collected from colonies near Lake Poygan
3. Analysis the mixtures of polyphenyls by gas chromatrogaphie. 1.- Area response for biphenyl and terphenyls relative to triphenylmethane; Analisis de polifenilos por cromatografia de gases 1.- Respuesta relativa del bifenilo y terfenilos respecto al trifenilmetano
Energy Technology Data Exchange (ETDEWEB)
Perez Garcia, M
1966-07-01
The relative performances of the thermal conductivity and flame ionization detectors towards triphenylmethane were investigated for each one of the components of biphenyl of biphenyl and terphenyl mixtures. The influence of the concentration of the considered compound as well as the influence derived from the present of all other components on the above-mentioned relative performance were studied. A 2 m long column filled with 50-70 mesh stomacher containing 20% apiezon L was used to carry out the study with the thermal conductivity detector by keeping the column at 300 degree centigree using helium gas as carrier. (Author) 13 refs.
4. Biphenyl-metabolizing bacteria in the rhizosphere of horseradish and bulk soil contaminated by polychlorinated biphenyls as revealed by stable isotope probing.
Science.gov (United States)
Uhlik, Ondrej; Jecna, Katerina; Mackova, Martina; Vlcek, Cestmir; Hroudova, Miluse; Demnerova, Katerina; Paces, Vaclav; Macek, Tomas
2009-10-01
DNA-based stable isotope probing in combination with terminal restriction fragment length polymorphism was used in order to identify members of the microbial community that metabolize biphenyl in the rhizosphere of horseradish (Armoracia rusticana) cultivated in soil contaminated with polychlorinated biphenyls (PCBs) compared to members of the microbial community in initial, uncultivated bulk soil. On the basis of early and recurrent detection of their 16S rRNA genes in clone libraries constructed from [(13)C]DNA, Hydrogenophaga spp. appeared to dominate biphenyl catabolism in the horseradish rhizosphere soil, whereas Paenibacillus spp. were the predominant biphenyl-utilizing bacteria in the initial bulk soil. Other bacteria found to derive carbon from biphenyl in this nutrient-amended microcosm-based study belonged mostly to the class Betaproteobacteria and were identified as Achromobacter spp., Variovorax spp., Methylovorus spp., or Methylophilus spp. Some bacteria that were unclassified at the genus level were also detected, and these bacteria may be members of undescribed genera. The deduced amino acid sequences of the biphenyl dioxygenase alpha subunits (BphA) from bacteria that incorporated [(13)C]into DNA in 3-day incubations of the soils with [(13)C]biphenyl are almost identical to that of Pseudomonas alcaligenes B-357. This suggests that the spectrum of the PCB congeners that can be degraded by these enzymes may be similar to that of strain B-357. These results demonstrate that altering the soil environment can result in the participation of different bacteria in the metabolism of biphenyl.
5. Anaerobic Dehalogenation of Hydroxylated Polychlorinated Biphenyls by Desulfitobacterium dehalogenans
OpenAIRE
Wiegel, Juergen; Zhang, Xiaoming; Wu, Qingzhong
1999-01-01
Ten years after reports on the existence of anaerobic dehalogenation of polychlorinated biphenyls (PCBs) in sediment slurries, we report here on the rapid reductive dehalogenation of para-hydroxylated PCBs (HO-PCBs), the excreted main metabolites of PCB in mammals, which can exhibit estrogenic and antiestrogenic activities in humans. The anaerobic bacterium Desulfitobacterium dehalogenans completely dehalogenates all flanking chlorines (chlorines in ortho position to the para-hydroxyl group) ...
6. Polychlorinated biphenyl reduction in lake trout by irradiation and broiling
International Nuclear Information System (INIS)
Cichy, R.F.; Zabik, M.E.; Weaver, C.M.
1979-01-01
The Great Lakes Environmental contaminants surveys (1974-1975) have concluded that excessive concentrations of polychlorinated biphenyls (PCBs) are present in a specific species of lake trout (Salvelinus namaycush). Over 30 ppM of PCBs have been detected in the edible fillet of this fat trout. The objective of this study was to determine the effect of gamma irradiation combined with broiling on the levels of PCBs in lake trout fillets
7. Polychlorinated Biphenyl Presence in the Columbia River Corridor
Energy Technology Data Exchange (ETDEWEB)
R. M. Hermann
2007-09-06
The U. S. Department of Energy (DOE) is required by Comprehensive Environmental Response, Compensation, and Liability Act of 1980 regulations to develop a conceptual understanding of potential contaminant releases from the Hanford Site based on an evaluation of existing data and known historical practices. Polychlorinated biphenyls (PCBs) are one environmental contaminant potentially released through leaks, spills, or disposal. This document presents a summary of selected relevant existing information, including environmental studies and Hanford Site analytical data.
8. Ortho-substituent correlated retention of polychlorinated biphenyls on a 50% n-octyl-methylpolysiloxane stationary phase by HRGC/MSD
Energy Technology Data Exchange (ETDEWEB)
Fischer, R.; Ballschmiter, K.
1988-11-01
Polychlorinated biphenyls (PCB) have been known as ubiquitous environmental pollutants since the late 60s. They are found partitioned between all environmental compartments according to their physico-chemical properties. Investigation of their partitioning, degradation, and transport behaviour demands sensitive and selective analytical methods for this complex mixture of up to 209 theoretically possible compounds. Congener-specific separation by high-resolution gas chromatography coupled with mass-selective detection would be a suitable approach to this multi-compound problem. In this paper, the separation of PCB congeners by capillary gas chromatography (HRGC) on a 50% n-octyl-methylpolysiloxane phase is presented.
9. Reactivity of polychlorinated biphenyls in nucleophilic and electrophilic substitutions
Energy Technology Data Exchange (ETDEWEB)
Gorbunova, Tatyana I., E-mail: gorbunova@ios.uran.ru [I. Ya. Postovskii Institute of Organic Synthesis, Ural Branch, Russian Academy of Sciences, Kovalevskoy St., 22, Ekaterinburg 620990 (Russian Federation); Subbotina, Julia O. [Ural Federal University named after the first President of Russia B.N. Yeltsin, Mira St., 19, Ekaterinburg 620002 (Russian Federation); Saloutin, Viktor I.; Chupakhin, Oleg N. [I. Ya. Postovskii Institute of Organic Synthesis, Ural Branch, Russian Academy of Sciences, Kovalevskoy St., 22, Ekaterinburg 620990 (Russian Federation)
2014-08-15
Graphical abstract: - Highlights: • Quantum chemical calculations were carried out for PCBs congeners. • Calculated descriptors were used to explain the PCBs reactivity in S{sub N} and S{sub E} substitutions. • Obtained data were used to estimate the PCBs reactivity in the S{sub N} reactions. • Calculated descriptors were insufficient to explain the PCBs reactivity in the S{sub E} reactions. • New neutralization methods of the large-capacity PCBs were discussed. - Abstract: To explain the chemical reactivity of polychlorinated biphenyls in nucleophilic (S{sub N}) and electrophilic (S{sub E}) substitutions, quantum chemical calculations were carried out at the B3LYP/6-31G(d) level of the Density Functional Theory in gas phase. Carbon atomic charges in biphenyl structure were calculated by the Atoms-in-Molecules method. Chemical hardness and global electrophilicity index parameters were determined for congeners. A comparison of calculated descriptors and experimental data for congener reactivity in the S{sub N} and S{sub E} reactions was made. It is shown that interactions in the S{sub N} mechanism are reactions of the hard acid–hard base type, these are the most effective in case of highly chlorinated substrates. To explain the congener reactivity in the S{sub E} reactions, correct descriptors were not established. The obtained results can be used to carry out chemical transformations of the polychlorinated biphenyls in order to prepare them for microbiological destruction or preservation.
10. Complete Reductive Dehalogenation of Brominated Biphenyls by Anaerobic Microorganisms in Sediment
Science.gov (United States)
Bedard, Donna L.; Van Dort, Heidi M.
1998-01-01
We sought to determine whether microorganisms from the polychlorinated biphenyl (PCB)-contaminated sediment in Woods Pond (Lenox, Mass.) could dehalogenate brominated biphenyls. The PCB dechlorination specificities for the microorganisms in this sediment have been well characterized. This allowed us to compare the dehalogenation specificities for brominated biphenyls and chlorinated biphenyls within a single sediment. Anaerobic sediment microcosms were incubated separately at 25°C with 16 different mono- to tetrabrominated biphenyls (350 μM) and disodium malate (10 mM). Samples were extracted and analyzed by gas chromatography with an electron capture detector and a mass spectrometer detector at various times for up to 54 weeks. All of the tested brominated biphenyls were dehalogenated. For most congeners, including 2,6-dibromobiphenyl (26-BB) and 24-25-BB, the dehalogenation began within 1 to 2 weeks. However, for 246-BB and 2-2-BB, debromination was first observed at 7 and 14 weeks, respectively. Most intermediate products did not persist, but when 2-2-BB was produced as a dehalogenation product, it persisted for at least 15 weeks before it was dehalogenated to 2-BB and then to biphenyl. The dehalogenation specificities for brominated and chlorinated biphenyls were similar: meta and para substituents were generally removed first, and ortho substituents were more recalcitrant. However, the brominated biphenyls were better dehalogenation substrates than the chlorinated biphenyls. All of the tested bromobiphenyls, including those with ortho and unflanked meta and para substituents, were ultimately dehalogenated to biphenyl, whereas their chlorinated counterparts either were not dehalogenation substrates or were only partially dehalogenated. Our data suggest that PCB-dechlorinating microorganisms may be able to dehalogenate brominated biphenyls and may exhibit a relaxed specificity for these substrates. PMID:16349530
11. 4-Substituted-2-Methoxyphenol: Suitable Building Block to Prepare New Bioactive Natural-like Hydroxylated Biphenyls.
Science.gov (United States)
Dettori, Maria Antonietta; Fabbri, Davide; Pisano, Marina; Rozzo, Carla; Palmieri, Giuseppe; Dess, Alessandro; Dallocchio, Roberto; Delogu, Giovanna
2015-02-01
A small collection of eugenol- and curcumin-analog hydroxylated biphenyls was prepared by straightforward methods starting from natural 4-substituted-2-methoxyphenols and their antitumoral activity was evaluated in vitro . Two curcumin-biphenyl derivatives showed interesting growth inhibitory activities on different malignant melanoma cell lines with IC 50 ranging from 13 to 1 µM. Preliminary molecular modeling studies were carried out to evaluate conformations and dihedral angles suitable for antiproliferative activity in hydroxylated biphenyls bearing a side aliphatic chain.
12. Crystal structure of (2E,3E-N2,N3-bis(3-ethyl-[1,1′-biphenyl]-4-ylbutane-2,3-diimine
Directory of Open Access Journals (Sweden)
Yan Zhao
2015-04-01
Full Text Available In the title compound, C32H32N2, synthesized by the condensation reaction of 2-ethyl-4-phenylaniline and 2,3-butanedione, the conformation about the C=N bonds is E and the substituted biphenyl units are trans to one another. In the two biphenyl ring systems, the planes of the two rings are inclined to one another by 25.25 (19 and 28.01 (19°. The planes of the ethyl-substituted benzene rings are inclined to one another by 20.23 (19° and to the mean plane of the butane-2,3-diimine unit [maximum deviation = 0.014 (4 Å] by 83.19 (19 and 63.38 (19°. In the crystal, molecules are linked by C—H...π interactions, forming sheets lying parallel to (101.
13. Role of rhizosphere microorganisms in phytoremediation of biphenyl in a contaminated groundwater plume
International Nuclear Information System (INIS)
Sun, B.; Ramsay, J.
2007-01-01
This presentation discussed a pump and treat technology used in combination with a phytoremediation technology to remediate a biphenyl contaminated groundwater plume. Biphenyl is used in industrial applications as fungicide and heat transfer agent. It is highly toxic, has poor water solubility and sorbs strongly to soils. Costs for the project were estimated at $860,000 over a period of 20 years, while it was estimated that the addition of phytoremediation would cost only$125,000 over a period of 20 years. The phytoremediation containment area was added to the site which was comprised of a pump and treat system and landfill lagoons. In situ biodegradation of biphenyl was evaluated using microorganisms in poplar and willow rhizospheres. Basal salts were used as a culture medium. Methods to enhance biphenyl degradation were also investigated. Aerobic growth on biphenyl at temperatures of 8 degrees C were measured, and microbial populations were identified. The consortium with the highest biphenyl degradation was then analyzed. Major members were identified as Burkholderia xenovorans LB400 and a strain of Burkholderia xenovorans. Nitrate reduction, sulphate reduction, and methanogens were measured. Enrichment of anaerobic biphenyl degraders. Anaerobic biphenyl degradation was measured after 90 days. Details of anaerobic mineralization experiments were also provided. It was concluded that anaerobic biphenyl degradation was enhanced by TEA and fertilizer addition, as well as by poplar root exudate. tabs., figs
14. Metabolism of polychlorinated biphenyls by marine bacteria
International Nuclear Information System (INIS)
Carey, A.E.; Harvey, G.R.
1978-01-01
There have been no reports of laboratory studies of PCB metabolism by marine organisms. A few workers have analyzed marine animals for products of PCB metabolism. A search for hydroxylated PCBs in marine fish proved inconclusive. Phenolic metabolites of PCBs have been identified in seals and guillemot. PCBs that had been hydroxylated and excreted by marine organisms would most likely be found in the sediments, so in our laboratory we conducted a search for these compounds in marine sediments. Two kilograms of organic-rich surface sediment from Buzzards Bay, Massachusetts, were extracted. The phenolic fraction was isolated and analyzed by gas chromatography-mass spectrometry (GC-MS). Neither wide mass scans nor selected mass searches produced any evidence of hydroxylated PCB derivatives. It was felt that if any marine organisms were capable of metabolism of PCBs, some marine bacteria should have that capability. Thus a series of laboratory experiments was conducted to test this possibility. Reported here is the finding of PCB metabolism by marine bacteria in batch culture
15. Biofilms at work: Bio-, phyto- and rhizoremediation approaches for soils contaminated with polychlorinated biphenyls
Directory of Open Access Journals (Sweden)
Merily Horwat
2015-09-01
Full Text Available Organohalide contaminants such as polychlorinated biphenyls (PCBs have been released into the environment for decades due to anthropogenic activities, but are also naturally produced in small amounts through volcanic eruptions and geochemical processes. Although toxic to humans and other organisms, the natural production of these compounds has resulted in the evolution of naturally occurring organohalide-respiring bacteria that possess the enzymes necessary to degrade PCB compounds to non-toxic products. The efficiency of PCB degradation can be improved by facilitating the formation of organohalide-respiring biofilms. During biofilm colonization on a surface or interface, bacteria are encased in an extracellular polymeric substance (EPS or “slime,” which allows them to share nutrients and remain protected from environmental stresses. Effective bioremediation of PCBs involves facilitation of biofilm growth to promote cooperation between bacteria, which can be further enhanced by the presence of certain plant species. This review aims to give an overview of biofilm processes involved in the detoxification of PCBs including anaerobic and aerobic PCB degradation by bacteria as well as the ability of plants to stimulate microbial activity and degradation (rhizoremediation and phytoremediation.
16. Health and productivity of dairy cows fed polychlorinated biphenyls
Energy Technology Data Exchange (ETDEWEB)
Willett, L.B.; Liu, T.T.; Durst, H.I.; Smith, K.L.; Redman, D.R.
1987-07-01
Holstein cows were studied through a complete lactation, a nonlactating period, and 42 days of a subsequent lactation for overt and subtle responses to a commercial mixture of polychlorinated biphenyls. Dosed cows (n = 4) received consecutive 60-day periods of daily dosing with 10, 100, and 1000 mg of Aroclor 1254. Control cows (n = 6) received daily sham doses. The following were recorded: daily milk production, feed intake, and health observations; weekly body weight, temperature, heart and respiratory rates and rectal palpation; semi-monthly clinical chemistry determinations; and monthly milk fat, microbiological culture of quarter foremilk samples, and composite milk somatic cell counts. Mean daily milk production (22.4 +/- 1.1 vs 24.8 +/- 1.0 kg) and net energy of a complete lactation (1.46 +/- 0.05 vs 1.45 +/- 0.03 Mcal/kg dry matter intake) were not different (p = 0.85) for control and PCB-dosed cows. Milk production during the first 42 days of the subsequent lactation was also similar for control and dosed cows. Occurrences of injuries, dysfunctions, and general infections were not related to polychlorinated biphenyl exposure. Intramammary infections were detected for both lactations with 51 and 32 infections detected in microbiological cultures, respectively, for the control and dosed groups. Environmental pathogens were most frequently isolated from cases of clinically apparent mastitis. The majority of quarter infections detected were due to Corynebacterium bovis. Only one animal (dosed, necropsy revealed left oviduct obstructed) failed to conceive with three to six services required before conception for the other control and dosed cows. Exposure to polychlorinated biphenyls resulting in maximal residues in milk fat, near 100 micrograms/g, had no apparent effect on health and productivity.
17. Ideal gas thermodynamic properties for the phenyl, phenoxy, and o-biphenyl radicals
Science.gov (United States)
Burcat, A.; Zeleznik, F. J.; Mcbride, B. J.
1985-01-01
Ideal gas thermodynamic properties of the phenyl and o-biphenyl radicals, their deuterated analogs and the phenoxy radical were calculated to 5000 K using estimated vibrational frequencies and structures. The ideal gas thermodynamic properties of benzene, biphenyl, their deuterated analogs and phenyl were also calculated.
18. Distribution of polychlorinated biphenyls, phthalic acid esters, polycyclic aromatic hydrocarbons and organochlorine substances in the Moscow River, Russia
International Nuclear Information System (INIS)
Eremina, Natalia; Paschke, Albrecht; Mazlova, Elena A.; Schüürmann, Gerrit
2016-01-01
The purpose of this study was to investigate the levels of polychlorinated biphenyl (PCB), phthalic acid esters (PAE), polycyclic aromatic hydrocarbons (PAH) and organochlorine substances (OCP) in the Moscow River water. Some studies have reported the occurrence of these substances in the soil of the Moscow region; however, no study has yet established an overview for these compounds in the Moscow River water. In this study the Moscow River water contamination with PAEs, PAHs and OCPs was determined. Obtained results were associated with the resident area located on the river bank, and the possible contamination sources were considered. The obtained data were compared with the data on the contamination of the different world-wide rivers. This research indicates the further study necessity of the Moscow region to cover more contaminated sites and environmental compartments. - Highlights: • The monitoring system creation of the Moscow River is necessary. • The wastewater plant is the source of the river contamination with triclosan. • The Moscow River is contaminated with the low chlorinated biphenyls. • There is a background contamination of the Moscow River with phthalates. - The organic pollutants contamination levels of the Moscow River were investigated.
19. Synthesis and antimicrobial properties of 3-aryl-1-(1,1'-biphenyl-4-yl)-2-(1H-imidazol-1-yl)propanes as 'carba-analogues' of the N-arylmethyl-N-[(1,1'-biphenyl)-4-ylmethyl])-1H-imidazol-1-amines, a new class of antifungal agents.
Science.gov (United States)
Castellano, Sabrina; Stefancich, Giorgio; Chillotti, Annalisa; Poni, Graziella
2003-08-01
A new series of 3-phenyl-1-(1,1'-biphenyl-4-yl)-2-(1H-imidazol-1-yl)propane derivatives 2a-l (related to the antifungal bifonazole) was synthesized and tested for antimicrobial activity. A number of substituents on the phenyl ring were chosen to compare the relative biological properties with those of corresponding aza-analogues, previously described by us. The in vitro antifungal activities of the newly synthesized azoles were tested against several pathogenic fungi responsible for human disease. Test pathogens included representatives of yeasts (Candida albicans, Candida parapsilosis, Criptococcus neoformans), dermathophytes (Tricophyton verrucosum, Tricophyton rubrum, Microsporum gypseum) and moulds (Aspergillus fumigatus). Bifonazole and miconazole were used as reference drugs. Title compounds were prepared by alkylation of 1-biphenyl-4-yl-2-imidazol-1-yl-ethanone with the proper arylmethyl halide and subsequent reduction of corresponding ketones applying the Huang-Minlon modification of the Wolff-Kishner reaction.
20. Biphenyl-Metabolizing Bacteria in the Rhizosphere of Horseradish and Bulk Soil Contaminated by Polychlorinated Biphenyls as Revealed by Stable Isotope Probing▿ †
Science.gov (United States)
Uhlik, Ondrej; Jecna, Katerina; Mackova, Martina; Vlcek, Cestmir; Hroudova, Miluse; Demnerova, Katerina; Paces, Vaclav; Macek, Tomas
2009-01-01
DNA-based stable isotope probing in combination with terminal restriction fragment length polymorphism was used in order to identify members of the microbial community that metabolize biphenyl in the rhizosphere of horseradish (Armoracia rusticana) cultivated in soil contaminated with polychlorinated biphenyls (PCBs) compared to members of the microbial community in initial, uncultivated bulk soil. On the basis of early and recurrent detection of their 16S rRNA genes in clone libraries constructed from [13C]DNA, Hydrogenophaga spp. appeared to dominate biphenyl catabolism in the horseradish rhizosphere soil, whereas Paenibacillus spp. were the predominant biphenyl-utilizing bacteria in the initial bulk soil. Other bacteria found to derive carbon from biphenyl in this nutrient-amended microcosm-based study belonged mostly to the class Betaproteobacteria and were identified as Achromobacter spp., Variovorax spp., Methylovorus spp., or Methylophilus spp. Some bacteria that were unclassified at the genus level were also detected, and these bacteria may be members of undescribed genera. The deduced amino acid sequences of the biphenyl dioxygenase α subunits (BphA) from bacteria that incorporated [13C]into DNA in 3-day incubations of the soils with [13C]biphenyl are almost identical to that of Pseudomonas alcaligenes B-357. This suggests that the spectrum of the PCB congeners that can be degraded by these enzymes may be similar to that of strain B-357. These results demonstrate that altering the soil environment can result in the participation of different bacteria in the metabolism of biphenyl. PMID:19700551
1. Formation of nitro products from the gas-phase OH radical-initiated reactions of toluene, naphthalene, and biphenyl: effect of NO2 concentration.
Science.gov (United States)
Nishino, Noriko; Atkinson, Roger; Arey, Janet
2008-12-15
Aromatic hydrocarbons, including polycyclic aromatic hydrocarbons (PAHs), are released into the atmosphere principally during incomplete combustion and account for approximately 20% of nonmethane organic compounds in urban air. Reaction with OH radicals is the dominant atmospheric chemical loss process for aromatic hydrocarbons, leading mainly to the formation of an OH-aromatic or OH-PAH adduct which then reacts with O2 and/or NO2. For OH-monocyclic aromatic adducts, reaction with O2 dominates under atmospheric conditions; however, no data are available concerning the relative importance of reactions of OH-PAH adducts with O2 and NO2. We have measured formation yields of 3-nitrotoluene, 1- and 2-nitronaphthalene, and 3-nitrobiphenyl from the OH radical-initiated reactions of toluene, naphthalene, and biphenyl as a function of NO2 concentration. Our data showthatthe OH-aromatic adduct reactions with O2 and NO2 are of equal importance in the atmosphere at NO2 mixing ratios of approximately 3.3 ppmV for toluene, approximately 0.06 ppmV for naphthalene, and approximately 0.6 ppmV for biphenyl. Ambient concentrations of toluene, naphthalene, and biphenyl and their nitrated products measured at a site in the Los Angeles air basin are consistent with our laboratory measurements.
2. Determination of polychlorinated biphenyls, selected persistent organochlorine pesticides, and polybrominated flame retardants in fillets of fishes from the 2007 Missouri Department of Conservation Monitoring Program
Science.gov (United States)
Gale, Robert W.; Orazio, Carl E.; McKee, Michael J.
2009-01-01
This report presents the results of a study to determine polychlorinated biphenyl, organochlorine pesticide, and polybrominated diphenylether flame retardant concentrations in selected fishes from lakes and streams across Missouri. Fillets were collected from each fish sample and after homogenization, compositing, and preparation, analyte concentrations were determined with dual column capillary gas chromatography-electron-capture detection. Total concentrations of polychlorinated biphenyls in samples ranged from background levels of about 50 to 300 nanograms per gram. In samples with elevated contaminant concentrations, chlordanes, DDT-related chemicals, and dieldrin constituted the primary classes of pesticides present, and ranged from 5 to 75 nanograms per gram. Total concentrations of polybrominated diphenyl ethers in samples ranged from background levels of 5 to 86 nanograms per gram. Channel catfish from the upper and lower Blue River and lake sturgeon from the Mississippi River at Saverton exhibited different polybrominated diphenyl ethers ratios. Concentrations of polychlorinated biphenyls, chlordanes, DDT-related compounds, and polybrominated diphenyl ethers all were greatest in samples of channel catfish from the upper and lower Blue River, and in samples of lake sturgeon from the Mississippi River at Saverton.
3. Biobatteries and biofuel cells with biphenylated carbon nanotubes
Science.gov (United States)
Stolarczyk, Krzysztof; Kizling, Michał; Majdecka, Dominika; Żelechowska, Kamila; Biernat, Jan F.; Rogalski, Jerzy; Bilewicz, Renata
2014-03-01
Single-walled carbon nanotubes (SWCNTs) covalently biphenylated are used for the construction of cathodes in a flow biobattery and in flow biofuel cell. Zinc covered with a hopeite layer is the anode in the biobattery and glassy carbon electrode covered with bioconjugates of single-walled carbon nanotubes with glucose oxidase and catalase is the anode of the biofuel cell. The potentials of the electrodes are measured vs. the Ag/AgCl reference electrode under changing loads of the fuel cell/biobattery. The power density of the biobattery with biphenylated nanotubes at the cathode is ca. 0.6 mW cm-2 and the open circuit potential is ca. 1.6 V. In order to obtain larger power densities and voltages three biobatteries are connected in a series which leads to the open circuit potential of ca. 4.8 V and power density 2.1 mW cm-2 at 3.9 V under 100 kΩ load. The biofuel cell shows power densities of ca. 60 μW cm-2 at 20 kΩ external resistance but the open circuit potential for such biofuel cell is only 0.5 V. The biobattery showing significantly larger power densities and open circuit voltages are especially useful for testing novel cathodes and applications such as powering units for clocks and sensing devices.
4. Momentum space analysis of the electronic structure of biphenyl
International Nuclear Information System (INIS)
Morini, F; Shojaei, S H Reza; Deleuze, M S
2014-01-01
The results of a yet to come experimental study of the electronic structure of biphenyl employing electron momentum spectroscopy (EMS) have been theoretically predicted, taking into account complications such as structural mobility in the electronic ground state, electronic correlation and relaxation, and a dispersion of the inner-valence ionization intensity to electronically excited (shake-up) configurations in the cation. The main purpose of this work is to explore the current limits of EMS in unraveling details of the molecular structure, namely the torsional characteristics of large and floppy aromatic molecules. At the benchmark ADC(3)/cc-pVDZ level of theory, the influence of the twist angle between the two phenyl rings is found to be extremely limited, except for individual orbital momentum profiles corresponding to ionization lines at electron binding energies ranging from 15 to 18 eV. When taking band overlap effects into account, this influence is deceptively far too limited to allow for any experimental determination of the torsional characteristics of biphenyl by means of EMS. (paper)
5. Decomposition of lignin model compounds by Lewis acid catalysts in water and ethanol
NARCIS (Netherlands)
Guvenatam, Burcu; Heeres, Erik H.J.; Pidko, Evgeny A.; Hensen, Emiel J. M.
2015-01-01
The conversion of benzyl phenyl ether, diphenyl ether, diphenyl methane and biphenyl as representative model compounds for alpha-O-4, 5-O-4, alpha(1) (methylene bridges) and 5-5' lignin linkages was investigated. We compared the use of metal chlorides and acetates. The reactions were studied in sub-
6. Changes in patterns of persistent halogenated compounds through a pelagic food web in the Baltic Sea
DEFF Research Database (Denmark)
Stephansen, Diana Agnete; Svendsen, Tore Christian; Vorkamp, Katrin
2012-01-01
The concentrations and patterns of persistent halogenated compounds (PHCs), including polychlorinated biphenyls (PCBs), DDT, hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB) and polybrominated diphenyl ethers (PBDEs) were examined in a pelagic food web from the southern Baltic Sea consisting...... for the assessment of PHC patterns, e.g. for tracing migratory fish....
7. Country-specific chemical signatures of persistent environmental compounds in breast milk
DEFF Research Database (Denmark)
Krysiak-Baltyn, Konrad; Toppari, J.; Skakkebaek, N.E.
2010-01-01
for exposure of the foetus to such agents. Therefore, we undertook a comprehensive ecological study of 121 EDCs, including the persistent compounds dioxins, polychlorinated biphenyls (PCBs), pesticides and flame retardants, and non-persistent phthalates, in 68 breast milk samples from Denmark and Finland...
8. Polychlorinated biphenyls and DDT in swordfish (Xiphias gladius) and blue shark (Prionace glauca) from Brazilian Coast. Preliminary results
Energy Technology Data Exchange (ETDEWEB)
Azevedo e Silva, C E; Azeredo, A; Meire, R; Torres, J P [Laboratorio de Radioisotopos E.P.F., Rio de Janeiro (Brazil). Inst. de Biofisica Carlos Chagas Filho, UFRJ; Brito, Jr, J L; Malm, O [Projeto Mamiferos Aquaticos, Rio de Janeiro (Brazil). Dept. de Oceanografia, UERJ
2004-09-15
There is conclusive evidence showing that, in general, fish in meals human diet contributes with a significant proportion of the total intake of PCBs and others organochlorine compounds, particularly fish with higher fat content. Thus, human exposure to PCBs is predominantly via diet, and especially from fish and seafood products. Comparatively, little is know about organochlorine contaminants in elasmobranch species, although they are also top predators. Characteristically, sharks are live longer, with comparatively slow rates of growth that in conjuction with their high trophic position may contribute to the accumulation of high concentrations of pollutants. Blue shark and swordfish are carnivorous fishes of great economic importance. This study investigate the concentration of polychlorinated biphenyls (PCBs) and DDTs in samples of muscle tissues of blue shark (Prionace glauca) and swordfish (Xiphias gladius) from Brazilian Coast.
9. Combined effect of microwave and activated carbon on the remediation of polychlorinated biphenyl-contaminated soil.
Science.gov (United States)
Liu, Xitao; Yu, Gang
2006-04-01
The application of microwave and activated carbon for the treatment of polychlorinated biphenyl (PCB) contaminated soil was explored in this study with a model compound of 2,4,5-trichlorobiphenyl (PCB29). PCB-contaminated soil was treated in a quartz reactor by microwave irradiation at 2450MHz with the addition of granular activated carbon (GAC). In this procedure, GAC acted as microwave absorbent for reaching high temperature and reductant for dechlorination. A sheltered type-K thermocouple was applied to record the temperature rising courses. It was shown that the addition of GAC could effectively promote the temperature rising courses. The determination of PCB residues in soil by gas chromatography (GC) revealed that rates of PCB removal were highly dependent on microwave power, soil moisture content, and the amount of GAC added. GC with mass spectrum (MS) detector and ion chromatography were employed for the analysis of degradation intermediates and chlorine ions, respectively. It was suggested that microwave irradiation with the assistance of activated carbon might be a potential technology for the remediation of PCB-contaminated soil.
10. Assessment of atmospheric distribution of polychlorinated biphenyls and polycyclic aromatic hydrocarbons using polyparameter model
Directory of Open Access Journals (Sweden)
Turk-Sekulić Maja M.
2011-01-01
Full Text Available Results of partial or total destruction of industrial plants, military targets, infrastructure, uncontrolled fires and explosions during the conflict period from 1991 to 1999, at the area of Western Balkans, were large amounts of hazardous organic matter that have been generated and emitted in the environment. In order to assess gas/particle partition of seven EPA polychlorinated biphenyls and sixteen EPA polycyclic aromatic hydrocarbons, twenty air samples have been collected at six urban, industrial and highly contaminated localities in Vojvodina. Hi-Vol methodology has been used for collecting ambiental air samples, that simultaneously collects gaseous and particulate phase with polyurethane foam filters (PUF and glass fiber filters (GFF. PUF and GFF filters have been analyzed, and concentration levels of gaseous PCBs and PAHs molecules in gaseous and particulate phase were obtained, converted and expressed through fraction of individual compounds sorbed onto particulate phase of the sample, in total detected quantity. Experimentally gained gas/particle partitioning values of PCBs and PAHs molecules have been compared with PP-LFER model estimated values. Significant deviation has been noticed during comparative analysis of estimated polyparameter model values for complete set of seven PCBs congeners. Much better agreement of experimental and estimated values is for polycyclic aromatic hydrocarbons, especially for molecules with four rings. These results are in a good correlation with literature data where polyparameter model has been used for predicting gas/particle partition of studied group of organic molecules.
11. Polychlorinated biphenyls in tree bark near a former manufacturing plant in Anniston, Alabama.
Science.gov (United States)
Hermanson, Mark H; Johnson, Glenn W
2007-05-01
Tree bark samples were collected to identify the relative amounts and congener profiles of atmospheric polychlorinated biphenyls dissolved into bark lipids from the gas phase in Anniston, Alabama, USA, where PCBs were manufactured from the 1920s until 1971. The area is heavily contaminated with PCBs: At least 4550 metric tons (mt) of PCB and 14000 mt of PCB distillation residue, known as Montar, remain buried in two landfills near the plant site. A minimum of 20.5 mt of PCBs were emitted to the atmosphere by the plant between 1953 and 1971 based on emissions figures for 1970. Bark results show that total PCB concentrations range over more than three orders of magnitude from 171927 ng/g lipid near the plant/landfill area, dropping exponentially to 35 ng/g lipid at a distance of about 7 km. The exponential trend is highly correlated (r=-0.77) and significant (ptree started growing after 1971 showing that atmospheric PCB concentrations remained high after PCB production ended. All PCB congener profiles show persistent congeners 31+28, 52, 66, 153, 138, and 180. Congener profiles from trees growing near the plant/landfill all have somewhat similar profiles but those growing during PCB production show high molecular mass compounds not usually found in the atmosphere and not found in younger trees, even in the most concentrated sample. We believe that high-temperature Montar disposal released high molecular mass PCBs into the gas phase which were dissolved into older tree bark lipids.
12. Specific accumulation of polychlorinated biphenyls and organochlorine pesticides in Japanese common squid as a bioindicator
International Nuclear Information System (INIS)
Ueno, D.; Inoue, S.; Ikeda, K.; Tanaka, H.; Yamada, H.; Tanabe, S.
2003-01-01
Japanese common squid is a suitable bioindicator for monitoring organochlorines pollution in waters around Japan. - Organochlorines (OCs) representing Persistent Organic Pollutants (POPs) such as PCBs (polychlorinated biphenyls), DDTs (DDT and its metabolites), CHLs (chlordane compounds), HCHs (hexachlorocyclohexane isomers) and HCB (hexachlorobenzene) were determined in the liver of Japanese common squid (Todarodes pacificus) collected from the waters around Japan (Japan Sea and western North Pacific Ocean). Among OCs concentrations, PCBs (upto 5600 ng/g lipid wt.) were the highest, and those of other OCs were in the order of DDT> CHLs > HCHs > HCB. Studies on growth trend and seasonal variation of OCs in this species suggest a rapid reflection of the pollution levels in seawater where and when they were collected, regardless of body-length and time of collection. These results indicate that Japanese common squid is a suitable bioindicator for monitoring OCs pollution in waters around Japan. With regard to the geographical distribution of OCs in this species collected from waters around Japan, OCs concentrations in specimens from Japan Sea were higher than those from the Pacific Ocean. This result might reflect some existing of local pollution sources of OCs around Japan Sea, and slower water exchange between Japan Sea and open ocean
13. Vapor solvent decontamination of PCB [polychlorinated biphenyls] transformer components
International Nuclear Information System (INIS)
Green, G.R.; Green, G.R.
1992-01-01
A process is provided to recover reclaimable material from discarded transformers containing PCB (polychlorinated biphenyl) insulating oils and to minimize the volume of materials which are subject to environmental regulation upon disposal. According to the invention, the transformer is drained and given an initial cleaning. The internal parts are removed and cleaned a second time as is the empty transformer casing. Recoverable materials such as aluminum and copper are cleaned to less than 10 μg of PCB per 100 cm 2 , allowing these materials to be recycled rather than buried. Almost all of the remaining nonmetallic materials are combustible solids or liquids which can be destroyed by incineration. The cleaning is accomplished using trichloroethylene solvent, chosen for its low boiling point which makes it easy to recycle using an isothermal separator. The removed transformer parts are cleaned in a secondary cleaning station consisting of 3 separate sections including tumbling baskets. 2 figs
14. Guidance on the management of polychlorinated biphenyls (PCBs)
Energy Technology Data Exchange (ETDEWEB)
1993-11-01
15. Spermatogenic capacity in fertile men with elevated exposure to polychlorinated biphenyls
DEFF Research Database (Denmark)
Petersen, Maria Skaalum; Halling, Jónrit; Weihe, Pál
2015-01-01
BACKGROUND: Endocrine disrupting industrial chemicals, such as polychlorinated biphenyls (PCBs), are suspected to adversely affect male reproductive functions. OBJECTIVES: The Faroe Islands community exhibits an unusually wide range of exposures to dietary contaminants, and in this setting we...
16. CATALYTIC STEAM REFORMING OF CHLOROCARBONS: POLYCHLORINATED BIPHENYLS (PCBS). (R826694C633)
Science.gov (United States)
Experiments with commercial askarals (Aroclors 1221, 1248 and 1254) have confirmed the feasibility of catalytic steam reforming as a method for destroying polychlorinated biphenyls (PCBs). Rhodium, platinum and nickel supported on Hydroxylated polychlorinated biphenyls increase reactive oxygen species formation and induce cell death in cultured cerebellar granule cells
International Nuclear Information System (INIS)
Dreiem, Anne; Rykken, Sidsel; Lehmler, Hans-Joachim; Robertson, Larry W.; Fonnum, Frode
2009-01-01
Polychlorinated biphenyls (PCBs) are persistent organic pollutants that bioaccumulate in the body, however, they can be metabolized to more water-soluble products. Although they are more readily excreted than the parent compounds, some of the metabolites are still hydrophobic and may be more available to target tissues, such as the brain. They can also cross the placenta and reach a developing foetus. Much less is known about the toxicity of PCB metabolites than about the parent compounds. In the present study, we have investigated the effects of eight hydroxylated (OH) PCB congeners (2'-OH PCB 3, 4-OH PCB 14, 4-OH PCB 34, 4'-OH PCB 35, 4-OH PCB 36, 4'-OH PCB 36, 4-OH PCB 39, and 4'-OH PCB 68) on reactive oxygen species (ROS) formation and cell viability in rat cerebellar granule cells. We found that, similar to their parent compounds, OH-PCBs are potent ROS inducers with potency 4-OH PCB 14 < 4-OH PCB 36 < 4-OH PCB 34 < 4'-OH PCB 36 < 4'-OH PCB 68 < 4-OH PCB 39 < 4'-OH PCB 35. 4-OH PCB 36 was the most potent cell death inducer, and caused apoptotic or necrotic morphology depending on concentration. Inhibition of ERK1/2 kinase with U0126 reduced both cell death and ROS formation, suggesting that ERK1/2 activation is involved in OH-PCB toxicity. The results indicate that the hydroxylation of PCBs may not constitute a detoxification reaction. Since OH-PCBs like their parent compounds are retained in the body and may be more widely distributed to sensitive tissues, it is important that not only the levels of the parent compounds but also the levels of their metabolites are taken into account during risk assessment of PCBs and related compounds.
17. Preliminary results of the comparison of the electrochemical behavior of a thioether and biphenyl
Science.gov (United States)
Morales, W.; Jones, W. R.
1983-01-01
An electrochemical cell was constructed to explore the feasibility of using electrochemical techniques to simulate the tribochemistry of various substances. The electrochemical cell was used to study and compare the behavior of a thioether 1,3-bis(phenylthio) benzene and biphenyl. It is found that under controlled conditions biphenyl undergoes a reversible reduction to a radical anion whereas the thioether undergoes an irreversible reduction yielding several products. The results are discussed in relationship to boundary lubrication.
18. Influence of Aroclor 1242 Concentration on Polychlorinated Biphenyl Biotransformations in Hudson River Test Tube Microcosms
Science.gov (United States)
Fish, K. M.
1996-01-01
When 93.3 to 933 (mu)mol of Aroclor 1242 per kg was added to Hudson River sediment test tube microcosms, the rates of polychlorinated biphenyl biotransformations increased with increasing Aroclor 1242 concentration after a 4- to 8-week acclimation period. In contrast, when 37.3 (mu)mol of Aroclor 1242 per kg was added, polychlorinated biphenyl biotransformations occurred at slow constant rates. PMID:16535387
19. Regional analysis of potential polychlorinated biphenyl degrading bacterial strains from China
Directory of Open Access Journals (Sweden)
Jianjun Shuai
Full Text Available ABSTRACT Polychlorinated biphenyls (PCBs, the chlorinated derivatives of biphenyl, are one of the most prevalent, highly toxic and persistent groups of contaminants in the environment. The objective of this study was to investigate the biodegradation of PCBs in northeastern (Heilongjiang Province, northern (Shanxi Province and eastern China (Shanghai municipality. From these areas, nine soil samples were screened for PCB-degrading bacteria using a functional complementarity method. The genomic 16S rDNA locus was amplified and the products were sequenced to identify the bacterial genera. Seven Pseudomonas strains were selected to compare the capacity of bacteria from different regions to degrade biphenyl by HPLC. Compared to the biphenyl content in controls of 100%, the biphenyl content went down to 3.7% for strain P9-324, 36.3% for P2-11, and 20.0% for the other five strains. These results indicate that a longer processing time led to more degradation of biphenyl. PCB-degrading bacterial strains are distributed differently in different regions of China.
1. [Polychlorinated biphenyls in fractions of wheat grains and in selected bakery products].
Science.gov (United States)
Brandt, Elzbieta; Pietrzak-Fiećko, Renata; Smoczyński, S S
2012-01-01
Polychlorinated biphenyls (PCBs) form a group of synthetic aromatic chemical compounds, commonly occurring in the environment as a result of industrialisation. Despite the ban on PCBs production, their wide application in the past resulted in their common occurrence in all elements of the environment. The lipophilic nature of the compounds resulting in their accumulation in live organisms and in the human body may trigger many harmful effects. The aim of this study was to determine the PCBs content in the selected species of wheat and in bakery products. The studies aiming at confirming possible correlation between the size of the grain of the selected species of wheat and the content of polychlorinated biphenyls were presented in this paper. Moreover, PCBs concentration in cereals' grains and in bread was compared. The PCBs content was defined in different sizes of grains species of wheat i.e. Opatka, Zyta, Elena and Almari. The study included also two kinds of wheat bread. PCBs were determined after the extraction with n-hexane followed by sulphuric acid hydrolysis. Gas chromatography analysis was conducted on a PU 4600 Unicam apparatus with an electron capture detector. The large variations in PCBs content depending on the grain size were confirmed. In the Opatka species the increase in the content of all determined congeners and the size of grain was confirmed. The lowest PCBs concentrations were in smallest grains (0,0090 mg/kg of fat), and the highest in the largest grains (0,0264 mg/kg of fat). In Zyta species PCBs content was also lowest in the smallest grains, however these results were not statistically significant. In the Elena species the increase in the PCBs content together with the increase in the grain size was confirmed. Basing on the determination coefficient it was found that the concentration of PCBs depends on the size of grains in 24%. The highest concentration of PCBs (0,0366 mg/kg of fat) was found in the largest grains, however differences
2. The use of the DR CALUX bioassay and indicator polychlorinated biphenyls for screening of elevated levels of dioxins and dioxin-like polychlorinated biphenyls in eel.
NARCIS (Netherlands)
Hoogenboom, Ron; Bovee, Toine; Traag, Win A; Hoogerbrugge, Ronald; Baumann, Bert; Portier, Liza; Weg, Guido van de; Vries, Jaap de
2006-01-01
The DR CALUX bioassay is a very suitable screening method for dioxins and dioxin-like-PCBs in feed and food. This was, e. g. demonstrated in a survey in the Netherlands to control the dioxin levels in eel. The DR CALUX assay, but also indicator polychlorinated biphenyls (PCB) were evaluated as a
3. Preconception maternal polychlorinated biphenyl concentrations and the secondary sex ratio
International Nuclear Information System (INIS)
Taylor, Kira C.; Jackson, Leila W.; Lynch, Courtney D.; Kostyniak, Paul J.; Buck Louis, Germaine M.
2007-01-01
The secondary sex ratio is the ratio of male to female live births and historically has ranged from 102 to 106 males to 100 females. Temporal declines have been reported in many countries prompting authors to hypothesize an environmental etiology. Blood specimens were obtained from 99 women aged 24-34 prior to attempting pregnancy and quantified for 76 polychlorinated biphenyl (PCB) congeners using dual column gas chromatography with electron capture detection. Women were prospectively followed until pregnancy or 12 cycles of trying. The odds of a male birth for three PCB groupings (total, estrogenic, anti-estrogenic) controlling for maternal characteristics were estimated using logistic regression. Among the 50 women with live births and PCB data, 26 female and 24 male infants were born (ratio 0.92). After adjusting for age and body mass index, odds of a male birth were elevated among women in the second (OR=1.29) and third (OR=1.48) tertiles of estrogenic PCBs; odds (OR=0.70) were reduced among women in the highest tertile of anti-estrogenic PCBs. All confidence intervals included one. The direction of the odds ratios in this preliminary study varied by PCB groupings, supporting the need to study specific PCB patterns when assessing environmental influences on the secondary sex ratio
4. Polychlorinated Biphenyls Water Pollution along the River Nile, Egypt
Directory of Open Access Journals (Sweden)
Ayman Mohamed Megahed
2015-01-01
Full Text Available Ten polychlorinated biphenyl (PCB congeners were determined in water samples collected along the River Nile using gas chromatography-electron capture detector (GC-ECD. PCB concentrations ranged from 14 to 20 μg/L, which were higher than those reported in previous studies, indicating serious PCB pollution in the River Nile. PCB congener profiles varied depending on the sampling sties. PCB-138 was the predominant congener accounting for more than 18% of total PCBs. The composition of PCB congeners in the water revealed that highly chlorinated PCB technical mixtures such as Aroclor 1254 was the main PCB production historically used in Egypt. An increasing trend in PCB levels from the upper stream to the Nile estuaries was observed. The calculated flux of PCBs indicated that 6.8 tons of PCBs is dumped into the Mediterranean Sea each year from the River Nile. The hazard quotients and carcinogenic risk caused by PCB pollution in the River Nile were above the acceptable level indicating that PCBs in the River Nile water pose adverse health effects for all age groups. Our findings revealed that PCBs possess a serious risk to the Egyptian population that depends mainly on the River Nile as a source of water. Thus, stricter legislation and regulatory controls should be applied to reduce the risk of PCBs in Egypt.
5. Phytoremediation of soil contaminated with cadmium, copper and polychlorinated biphenyls.
Science.gov (United States)
Wu, Longhua; Li, Zhu; Han, Cunliang; Liu, Ling; Teng, Ying; Sun, Xianghui; Pan, Cheng; Huang, Yujuan; Luo, Yongming; Christie, Peter
2012-07-01
A pot experiment and afield trial were conducted to study the remediation of an aged field soil contaminated with cadmium, copper and polychlorinated biphenyls (PCBs) (7.67 +/- 0.51 mg kg(-1) Cd, 369 +/- 1 mg kg(-1) Cu in pot experiment; 8.46 +/- 0.31 mg kg(-1) Cd, 468 +/- 7 mg kg(-1) Cu, 323 +/- 12 microg kg(-1) PCBs for field experiment) under different cropping patterns. In the pot experiment Sedum plumbizincicola showed pronounced Cd phytoextraction. After two periods (14 months) of cropping the Cd removal rates in these two treatments were 52.2 +/- 12.0 and 56.1 +/- 9.1%, respectively. Total soil PCBs in unplanted control pots decreased from 323 +/- 11 to 49.3 +/- 6.6 microg kg(-1), but with no significant difference between treatments. The field microcosm experiment intercropping of three plant species reduced the yield of S. plumbizincicola, with a consequent decrease in soil Cd removal. S. plumbizincicola intercropped with E. splendens had the highest shoot Cd uptake (18.5 +/- 1.8 mg pot(-1)) after 6 months planting followed by intercropping with M. sativa (15.9 +/- 1.9 mg pot(-1)). Liming with S. plumbizincicola intercropped with M. sativa significantly promoted soil PCB degradation by 25.2%. Thus, adjustment of soil pH to 5.56 combined with intercropping with S. plumbizincicola and M. sativagave high removal rates of Cd, Cu, and PCBs.
6. Sex effect on polychlorinated biphenyl concentrations in fish: a synthesis
Science.gov (United States)
2011-01-01
Polychlorinated biphenyls (PCBs) accumulate in fish primarily via food intake, and therefore, PCBs serve as a chemical tracer for food consumption. Sex differences in PCB concentrations of fish have been attributed to the following three mechanisms: (i) females losing a substantial portion of their PCB body burden during spawning and consequently their PCB concentration is considerably reduced immediately after spawning; (ii) sex differences in habitat utilization leading to sex differences in the PCB concentrations of the prey; and (iii) sex differences in gross growth efficiency, which is defined as growth divided by the amount of food consumption needed to achieve that growth. Based on my analyses and synthesis, mechanisms (i) and (ii) operate in relatively few fish populations, but can lead to mature males having PCB concentrations two to three times higher than mature female PCB concentrations. In contrast, mechanism (iii) operates in all fish populations, but typically, mechanism (iii) results in relatively modest sex differences, with mature males only between 15 and 35% higher in PCB concentration than mature females. In summary, the study of sex differences in PCB concentrations of fish has led to insights into fish behaviour and fish physiology.
7. Organochlorine pesticides and polychlorinated biphenyls in California sea lions
Energy Technology Data Exchange (ETDEWEB)
Kannan, K.; Kajiwara, N.; Le Boeuf, B.J.; Tanabe, S
2004-10-01
Concentrations of polychlorinated biphenyls (PCBs), DDTs, chlordanes, HCHs, hexachlorobenzene (HCB), dieldrin, heptachlor epoxide, tris(4-chlorophenyl)methane (TCPMe), and tris(4-chlorophenyl)methanol (TCPMOH) were measured in the blubber of California sea lions (Zalophus californianus) collected in 2000. DDTs were the most predominant contaminants, followed by PCBs, chlordanes, TCPMe, HCHs, TCPMOH, dieldrin, and heptachlor epoxide. Concentrations of PCBs and DDTs varied from a few {mu}g/g to several hundreds of {mu}g/g on a lipid weight basis. Concentrations of DDTs have declined by an order of magnitude over the last three decades in California sea lions; nevertheless, the measured concentrations of PCBs and DDTs in California sea lions are still some of the highest values reported for marine mammals in recent years. Concentrations of organochlorines were highly correlated with one another. Concentrations of PCBs and DDTs in the blubber of gray whale, humpback whale, northern elephant seal, and harbor seal, and in the adipose fat of sea otter, were lower than the levels found in California sea lions, and were in the range of a few to several {mu}g/g on a lipid weight basis.
8. Prenatal exposure to polychlorinated biphenyls: a neuropsychologic analysis.
Science.gov (United States)
Boucher, Olivier; Muckle, Gina; Bastien, Célyne H
2009-01-01
A large body of literature documents the effects of prenatal exposure to polychlorinated biphenyls (PCBs) on cognitive development of children. Despite this fact, no integrative synthesis has been published yet to identify the cognitive functions that are particularly affected. Our aim is to review this literature in an attempt to identify the cognitive profile associated with prenatal PCB exposure. Studies were identified by searching the PubMed database for articles published before June 2008. We reviewed data from nine prospective longitudinal birth cohorts for different aspects of cognition. Associations between indicators of prenatal PCB exposure and performance on cognitive tasks reported in the selected studies are summarized and classified as general cognitive abilities, verbal or visual-spatial skills, memory, attention, and executive functions. The most consistent effects observed across studies are impaired executive functioning related to increased prenatal PCB exposure. Negative effects on processing speed, verbal abilities, and visual recognition memory are also reported by most studies. Converging results from different cohort studies in which exposure arises from different sources make it unlikely that co-exposure with another associated contaminant is responsible for the observed effects. Prenatal PCB exposure appears to be related to a relatively specific cognitive profile of impairments. Failure to assess functions that are specifically impaired may explain the absence of effects found in some studies. Our findings have implications in the selection of cognitive assessment methods in future studies.
9. Polychlorinated Biphenyls Water Pollution along the River Nile, Egypt.
Science.gov (United States)
Megahed, Ayman Mohamed; Dahshan, Hesham; Abd-El-Kader, Mahdy A; Abd-Elall, Amr Mohamed Mohamed; Elbana, Mariam Hassan; Nabawy, Ehab; Mahmoud, Hend A
2015-01-01
Ten polychlorinated biphenyl (PCB) congeners were determined in water samples collected along the River Nile using gas chromatography-electron capture detector (GC-ECD). PCB concentrations ranged from 14 to 20 μg/L, which were higher than those reported in previous studies, indicating serious PCB pollution in the River Nile. PCB congener profiles varied depending on the sampling sties. PCB-138 was the predominant congener accounting for more than 18% of total PCBs. The composition of PCB congeners in the water revealed that highly chlorinated PCB technical mixtures such as Aroclor 1254 was the main PCB production historically used in Egypt. An increasing trend in PCB levels from the upper stream to the Nile estuaries was observed. The calculated flux of PCBs indicated that 6.8 tons of PCBs is dumped into the Mediterranean Sea each year from the River Nile. The hazard quotients and carcinogenic risk caused by PCB pollution in the River Nile were above the acceptable level indicating that PCBs in the River Nile water pose adverse health effects for all age groups. Our findings revealed that PCBs possess a serious risk to the Egyptian population that depends mainly on the River Nile as a source of water. Thus, stricter legislation and regulatory controls should be applied to reduce the risk of PCBs in Egypt.
10. Binding properties of halogenated biphenyls to cells and macromolecules
International Nuclear Information System (INIS)
Pepe, M.G.
1982-01-01
The interaction of polychlorinated biphenyls (PCB) with serum proteins may help explain the cellular incorporation of PCB as the effect of PCB on thyroid hormone function. PCB reduces serum thyroxine and triiodothyronine levels in rats; the mechanism for this effect is unknown. The initial distribution of PCB from blood to tissue is rapid and depends on blood perfusion and tissue affinity; however, the translocation of unmetabolized PCB from its initial storage sites to adipose tissue may depend on serum and cellular protein interactions. Therefore, the ability of PCB to displace triiodothyronine binding to albumin and antibodies, as well as the effect of binding to serum proteins as a mechanism for cellular incorporation was measured. PCB binding to albumin showed both high and low affinity binding sites. This binding was able to prevent triiodothyronine binding to albumin. The distribution of PCB inserum showed that lipoproteins contained 94% of the total 14 C PCB added, while 5% of the 14 C PCB was bound to albumin. The in vitro binding of 14 C PCB to serum obtained from rats pretreated with PCB in their diets for 6 months showed a significant decrease (p 14 C PCB was higher (p < 0.05) in liver, adrenal and adipose cells than pituitary and thyroid cells
11. Remediation of PCB [polychlorinated biphenyl] -contaminated soils from scrapyards
International Nuclear Information System (INIS)
MacKnight, S.
1991-01-01
Much of the recent attention on contamination of the environment by polychlorinated biphenyls (PCB) has focused on liquid PCB spills from electrical equipment. A new, and possibly more serious, source of PCB contamination is the scrap yard, typically located in or near major urban centers, where the local scrap dealer would purchase used transformers or other PCB-containing electrical equipment, recover copper and other metals, and dump the PCB-containing oils on the ground. With the rising value of urban and suburban lands, these scrap yards may be slated for redevelopment, making the cleanup of contaminated soils necessary. The heterogeneous distribution of scrap yard contaminants requires a very detailed site assessment, and the heterogeneous mixture of typical scrap yard contaminants (not only PCB) cannot be treated in a simple fashion. These problems are illustrated for the case of the assessment and cleanup of a scrap yard site in Nova Scotia. A grid block system was used to sample soil at the site, and samples were analyzed for PCB, metals, and hydrocarbons. The most severely contaminated spots were mapped; groundwater patterns were also examined. The remediation process can be divided into 5 phases: physical separation of uncontaminated material; three stages of separation of materials into those having single, several-but-similar, and multicomponent mixed contaminations; and selection of appropriate process technologies. Since there is currently no approved PCB destruction facility in Atlantic Canada, excavated soils containing PCB are stored securely on the site to await approval for some type of incineration process
12. Organochlorine pesticides and polychlorinated biphenyls in California sea lions
International Nuclear Information System (INIS)
Kannan, K.; Kajiwara, N.; Le Boeuf, B.J.; Tanabe, S.
2004-01-01
Concentrations of polychlorinated biphenyls (PCBs), DDTs, chlordanes, HCHs, hexachlorobenzene (HCB), dieldrin, heptachlor epoxide, tris(4-chlorophenyl)methane (TCPMe), and tris(4-chlorophenyl)methanol (TCPMOH) were measured in the blubber of California sea lions (Zalophus californianus) collected in 2000. DDTs were the most predominant contaminants, followed by PCBs, chlordanes, TCPMe, HCHs, TCPMOH, dieldrin, and heptachlor epoxide. Concentrations of PCBs and DDTs varied from a few μg/g to several hundreds of μg/g on a lipid weight basis. Concentrations of DDTs have declined by an order of magnitude over the last three decades in California sea lions; nevertheless, the measured concentrations of PCBs and DDTs in California sea lions are still some of the highest values reported for marine mammals in recent years. Concentrations of organochlorines were highly correlated with one another. Concentrations of PCBs and DDTs in the blubber of gray whale, humpback whale, northern elephant seal, and harbor seal, and in the adipose fat of sea otter, were lower than the levels found in California sea lions, and were in the range of a few to several μg/g on a lipid weight basis
13. Activated carbon immobilizes residual polychlorinated biphenyls in weathered contaminated soil.
Science.gov (United States)
Langlois, Valérie S; Rutter, Allison; Zeeb, Barbara A
2011-01-01
Activated carbon (AC) has recently been shown to be effective in sequestering persistent organic pollutants (POPs) from aquatic sediments. Most studies have demonstrated significant reductions of POP concentrations in water and in aquatic organisms; however, limited data exist on the possibility of using AC to immobilize remaining POPs at terrestrial contaminated sites. Under greenhouse conditions, pumpkin ssp cv. Howden) were grown, and red wiggler worms () were exposed to an industrial contaminated soil containing a mixture of polychlorinated biphenyls (PCBs), i.e., Aroclors 1254 and 1260) treated with one of four concentrations of AC (0.2, 0.8, 3.1, and 12.5%) for 2 mo. The addition of AC to contaminated soils virtually eliminated the bioavailability of PCBs to the plant and invertebrate species. There were reductions in PCB concentrations of more than 67% in ssp and 95% in . These data suggest that AC could be included as part of comprehensive site closure strategy at PCB-contaminated sites. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.
14. Organochlorine pesticides and polychlorinated biphenyls in fin whales (Balaenoptera physalus) from the Gulf of California.
Science.gov (United States)
Niño-Torres, Carlos Alberto; Zenteno-Savín, Tania; Gardner, Susan C; Urbán R, Jorge
2010-08-01
The present study reports unique data on concentrations of several classes of organochlorine pesticides and polychlorinated biphenyls in blubber biopsies from healthy living fin whales (Balaenoptera physalus) from the Gulf of California, Mexico, one of the most isolated and unstudied population in the world. OC levels in this population were generally lower than levels reported in fin whales from other regions. The rank order of OCs were SigmaDDTs (range from 300 to 2400 ng g(-1) lw) > SigmaPCBs (range from 40 to 290 ng g(-1) lw) > SigmaHCHs (range from or = SigmaCHLORs (from pesticide measured was the DDT metabolite, p,p'-DDE. The PCBs 138, 153, and 180 were the most abundant PCBs congeners found in the fin whales samples. Males had significant higher concentrations of SigmaOC, SigmaDDTs and SigmaPCBs than females (P < 0.05), although the p,p'-DDE/SigmaDDTs ratios were similar between the sexes. Although the OC concentrations found in this population were generally below the levels that would be expected to cause deleterious health effects, the maximum values observed (2700 ng g(-1) lw) in some animals were higher than those associated with reproductive effects in whales. Given the small population size and highly isolated characteristics of Gulf of California fin whales, health effects in individuals could readily translate into population-level effects. Future research on this topic will be necessary to better understand the role that these compounds may have on the health of this population.
15. Latitudinal and seasonal capacity of the surface oceans as a reservoir of polychlorinated biphenyls
International Nuclear Information System (INIS)
Jurado, Elena; Lohmann, Rainer; Meijer, Sandra; Jones, Kevin C.; Dachs, Jordi
2004-01-01
The oceans play an important role as a global reservoir and ultimate sink of persistent organic pollutants (POPs) such as polychlorinated biphenyls congeners (PCBs). However, the physical and biogeochemical variables that affect the oceanic capacity to retain PCBs show an important spatial and temporal variability which have not been studied in detail, so far. The objective of this paper is to assess the seasonal and spatial variability of the ocean's maximum capacity to act as a reservoir of atmospherically transported and deposited PCBs. A level I fugacity model is used which incorporates the environmental variables of temperature, phytoplankton biomass, and mixed layer depth, as determined from remote sensing and from climatological datasets. It is shown that temperature, phytoplankton biomass and mixed layer depth influence the potential PCB reservoir of the oceans, being phytoplankton biomass specially important in the oceanic productive regions. The ocean's maximum capacities to hold PCBs are estimated. They are compared to a budget of PCBs in the surface oceans derived using a level III model that assumes steady state and which incorporates water column settling fluxes as a loss process. Results suggest that settling fluxes will keep the surface oceanic reservoir of PCBs well below its maximum capacity, especially for the more hydrophobic compounds. The strong seasonal and latitudinal variability of the surface ocean's storage capacity needs further research, because it plays an important role in the global biogeochemical cycles controlling the ultimate sink of PCBs. Because this modeling exercise incorporates variations in downward fluxes driven by phytoplankton and the extent of the water column mixing, it predicts more complex latitudinal variations in PCBs concentrations than those previously suggested. - Model calculations estimate the latitudinal and seasonal storage capacity of the surface oceans for PCBs
16. Contamination of freshwater fish from rivers Sava and Danube with polychlorinated biphenyls
International Nuclear Information System (INIS)
Jankovic, S.; Radicevic, T.; Spiric, A.; Nedeljkovic, M.
2002-01-01
During air strikes, in april 1999, Institute of meat hygiene and technology have begun examination of freshwater fish to establish the degree of contamination. The information about damaged industrial facilities and toxic waste that have been spilled were hard to find, and was unofficial and contradicts. Because of that, at the first time we collected samples from different locations, but after first results, we concentrated our attention on locations on river Danube downstream from Pancevo and on river Sava upstream from Belgrade, the locations indicated as environmental 'hot spots'. According to our experience, knowledge, equipment and analytical skills we have chosen to determine the concentrations of PCBs in freshwater fish species, since aquatic fauna might be used as indicator organisms for the evaluation of water pollution. Polychlorinated biphenyls as contaminant of interest, have been chosen because large quantities of PCBs reached the soil and waste and ground waters from damaged transformers and capacitors, where they serve as dielectric fluids. Also, PCBs are highly toxic and due to their liposolubility and persistence, these compounds accumulate through food chain. In 1999, from April to December, we had collected 23 samples of different fish species on river Danube, downstream from Pancevo and 15 samples from locations on river Sava upstream from Belgrade. The concentrations of PCBs (mg/kg fat and mg/kg fresh weight) were expressed as the sum of individual congeners (IUPAC numbers 28, 52, 101, 138, 153, 180) and as Aroclor 1260 (peaks were identified as a fingerprint pattern by comparison with Aroclor standards). The concentrations of PCBs (mg/kg fat) are determined to evaluate the extent of contamination and concentrations of PCBs (mg/kg fresh weight) indicate daily intake and help us to estimate the risk for human health. Residues of PCBs in the fat extracted from fish sample were analysed according to the USDA Analytical Chemistry Guidebook. Gas
17. Environmental Polychlorinated Biphenyl Exposure and Breast Cancer Risk: A Meta-Analysis of Observational Studies.
Directory of Open Access Journals (Sweden)
Jingwen Zhang
Full Text Available Association between polychlorinated biphenyl (PCB exposure and breast cancer risk has been widely studied, but the results remain controversial. We performed a meta-analysis to evaluate the evidences from observational studies on PCB exposure and breast cancer risk.Relevant studies with data on internal PCB dose were identified from PubMed, EMBASE, CBM and CNKI databases through November 2014. Multivariable-adjusted odds ratio (OR with 95% confidence intervals (CIs were applied to assess the association between PCB exposure and breast cancer risk. Heterogeneity test, sensitivity analysis, subgroup analysis and publication bias test were also performed. To further explore the association between specific groups of PCB congeners and breast cancer, we examined the PCB congeners classified, according to their structural, biological and pharmacokinetics properties, as group I (potentially estrogenic, group II (potentially anti-estrogenic and immunotoxic, dioxin-like, and group III (phenobarbital, CYP1A and CYP2B inducers, biologically persistent.Of 660 studies screened, 25 studies which met criteria were selected, involving a total of 12866 participants (6088 cases and 6778 controls from eight countries. The results showed that the risk of breast cancer was associated with group II (OR = 1.23, 95% CI: 1.08-1.40 and group III (OR = 1.25, 95% CI: 1.09-1.43 PCBs, but not with group I (OR = 1.10, 95%CI: 0.97-1.24 PCBs or total PCB exposure (OR = 1.09, 95%CI: 0.97-1.22.Our meta-analysis based on the selected studies found group II and group III PCB exposure might contribute to the risk of breast cancer. More studies in developing countries with higher PCB levels are needed, as well as studies to explore the relationships between mixtures of organochlorine compounds and breast cancer risk.
18. Occurrence and exposure assessment of polychlorinated biphenyls and organochlorine pesticides from homemade baby food in Korea.
Science.gov (United States)
Jeong, Yunsun; Lee, Sunggyu; Kim, Sunmi; Choi, Sung-Deuk; Park, Jeongim; Kim, Hai-Joong; Lee, Jeong Jae; Choi, Gyuyeon; Choi, Sooran; Kim, Sungjoo; Kim, Su Young; Kim, Young Don; Cho, Geumjoon; Suh, Eunsook; Kim, Sung Koo; Eun, So-Hee; Eom, Soyong; Kim, Seunghyo; Kim, Gun-Ha; Choi, Kyungho; Kim, Sungkyoon; Moon, Hyo-Bang
2014-02-01
Data on the residue levels of persistent organic pollutants (POPs) in baby food samples are scarce. This is the first study to explore current contamination status and exposure assessment of organochlorines (OCs), including polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), in baby food from Korea. In this study, the concentrations of OCs were determined in homemade baby food samples (n=100) collected from 6-, 9-, 12- and 15-month-old infant groups. The average concentrations of PCBs, dichloro-diphenyl-trichloroethanes (DDTs), hexachlorocyclohexanes (HCHs) and chlordanes (CHLs) in baby food samples were 37.5, 96.6, 26.0, and 13.2 pg/g fresh weight, respectively. The major compounds were CBs 28, 153, 52, and 33 for PCBs and p,p'-DDE, p,p'-DDT and β-HCH for OCPs. The contribution of DDTs to the total OC concentrations increased from 30% (6-month-old infants) to 67% (15-month-old infants) with increasing infant age, while the concentrations of PCBs, HCHs and CHLs gradually decreased with increasing infant age, suggesting that highest priority for risk reduction of DDTs. The estimated daily intakes (EDIs) of OCs in Korean infants from baby food consumption were lower than the thresholds proposed by the United States Environmental Protection Agency and Health Canada, implying limited potential health risks. However, considering simultaneous exposure from baby food and breast milk consumption, chlordanes and heptachlor epoxide posed potential health risks. Considering the importance of early development and the vulnerability of infants, it is essential to perform systematic monitoring and management programs of OCs in baby food for risk reduction in Korean infants. © 2013 Elsevier B.V. All rights reserved.
19. Sulfate radical-based degradation of polychlorinated biphenyls: Effects of chloride ion and reaction kinetics
Energy Technology Data Exchange (ETDEWEB)
Fang, Guo-Dong [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Dionysiou, Dionysios D. [Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0071 (United States); Wang, Yu [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Al-Abed, Souhail R. [National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268 (United States); Zhou, Dong-Mei, E-mail: dmzhou@issas.ac.cn [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China)
2012-08-15
20. Chronic treatment with polychlorinated biphenyls (PCB) during pregnancy and lactation in the rat
International Nuclear Information System (INIS)
Cocchi, Daniela; Tulipano, Giovanni; Colciago, Alessandra; Sibilia, Valeria; Pagani, Francesca; Vigano, Daniela; Rubino, Tiziana; Parolaro, Daniela; Bonfanti, Patrizia; Colombo, Anita; Celotti, Fabio
2009-01-01
Polychlorinated biphenyls (PCBs) are pollutants detected in animal tissues and breast milk. The experiments described in the present paper were aimed at evaluating whether the four PCB congeners most abundant in animal tissues (PCB-138, -153, -180 and -126), administered since fetal life till weaning, can induce long-term alterations of GH-axis activity and bone mass in the adult rat. We measured PCB accumulation in rat brain and liver, somatic growth, pituitary GH expression and plasma hormone concentrations at different ages. Finally, we studied hypothalamic somatostatin expression and bone structure in adulthood, following long-term PCB exposure. Dams were treated during pregnancy from GD15 to GD19 and during breast-feeding. A constant reduction of the growth rate in both male and female offspring from weaning to adulthood was observed in exposed animals. Long-lasting alterations on hypothalamic-pituitary GH axis were indeed observed in PCB-exposed rats in adulthood: increased somatostatin expression in hypothalamic periventricular nucleus (both males and females) and lateral arcuate nucleus (males, only) and decreased GH mRNA levels in the pituitary of male rats. Plasma IGF-1 levels were higher in PCB-exposed male and female animals as compared with controls at weaning and tended to be higher at PN60. Plasma testosterone and thyroid hormone concentrations were not significantly affected by exposure to PCBs. In adulthood, PCBs caused a significant reduction of bone mineral content and cortical bone thickness of tibiae in male rat joint to increased width of the epiphyseal cartilage disk. In conclusion, the developmental exposure to the four selected PCB compounds used in the present study induced far-reaching effects in the adult offspring, the male rats appearing more sensitive than females.
1. Design and synthesis of 4'-((5-benzylidene-2,4-dioxothiazolidin-3-yl)methyl)biphenyl-2-carbonitrile analogs as bacterial peptide deformylase inhibitors.
Science.gov (United States)
Khan, Firoz A Kalam; Patil, Rajendra H; Shinde, Devanand B; Sangshetti, Jaiprakash N
2016-12-01
Herein, we report the synthesis and screening of 4'-((5-benzylidene-2,4-dioxothiazolidin-3-yl)methyl)biphenyl-2-carbonitrile analogs 11(a-j) as bacterial peptide deformylase (PDF) enzyme inhibitors. The compounds 11b (IC 50 value = 139.28 μm), 11g (IC 50 value = 136.18 μm), and 11h (IC 50 value = 131.65 μm) had shown good PDF inhibition activity. The compounds 11b (MIC range = 103.36-167.26 μg/mL), 11g (MIC range = 93.75-145.67 μg/mL), and 11h (MIC range = 63.61-126.63 μg/mL) had also shown potent antibacterial activity when compared with standard ampicillin (MIC range = 100.00-250.00 μg/mL). Thus, the active derivatives were not only PDF inhibitors but also efficient antibacterial agents. To gain more insight on the binding mode of the compounds with PDF enzyme, the synthesized compounds 11(a-j) were docked against PDF enzyme of Escherichia coli and compounds exhibited good binding properties. The results suggest that this class of compounds has potential for development and use in future as antibacterial drugs. © 2016 John Wiley & Sons A/S.
2. Combined effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and polychlorinated biphenyls congeners in rats
Energy Technology Data Exchange (ETDEWEB)
Chu, I. [Environmental Science Bureau, Ottawa (Canada); Valli, V.E. [Coll. of Veterinary Medicine, Urbana (United States)
2004-09-15
There has been considerable interest in conducting toxicity studies on mixtures since this approach represents realistic human exposure and would provide a better model to predict the health impacts of environmental chemicals. However, risk assessment of the chemicals is largely based on the toxicity data of individual compounds by assuming simple additive effects of these compounds. This practice has been accepted by regulatory agencies provided that the concentrations of chemicals are extremely low, and there are no interactions. The existence of interactions among the chemicals co-administered to test animals may under or over estimate the effects of a mixture if the simple additive rule is applied. Previously, we demonstrated an antagonistic effect in rats when tetrachlorodibenzo-p-dioxin (TCDD) was co-administered with polychlorinated biphenyls congeners (PCBs). The hepatic microsomal EROD, MROD and UDPGT activities of TCDD were decreased when co-administered with PCB congeners. To further explore the combined effects of these pollutants, we examined and report results on tissue residue levels of TCDD and histopathological changes in target organs of rats exposed to TCDD, PCBs and mixtures of both.
3. Process for removing halogenated aliphatic and aromatic compounds from petroleum products
Science.gov (United States)
Googin, J.M.; Napier, J.M.; Travaglini, M.A.
1983-09-20
A process is described for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 1 fig.
4. Association between polychlorinated biphenyls and Parkinson's disease neuropathology.
Science.gov (United States)
Hatcher-Martin, Jaime M; Gearing, Marla; Steenland, Kyle; Levey, Allan I; Miller, Gary W; Pennell, Kurt D
2012-10-01
Polychlorinated biphenyls (PCBs) are synthetic chemicals primarily used as coolants and insulators in electrical equipment. Although banned for several decades, PCBs continue to exist in the environment because of their long half-life, continued presence in items produced before the ban, and poor disposal practices. Epidemiological and experimental studies have identified exposure to PCBs as a potential risk factor for Parkinson's disease, perhaps more so in females. The objective of this work was to examine the association between PCB levels in post-mortem human brain tissue and the diagnosis of Parkinson's disease, as well as the degree of nigral depigmentation. We also sought to determine if this association was more significant when patients were stratified by sex. Post-mortem brain samples from control patients and those diagnosed with Parkinson's disease were obtained from the Emory University Brain Bank and from the Nun Study. Concentrations of eight prevalent PCB congeners were extracted from post-mortem brain tissue and analyzed using gas chromatography-mass spectrometry. PCB congeners 153 and 180 were significantly elevated in the brains of Parkinson's disease patients. When stratified by sex, the female Parkinson's disease group demonstrated significantly elevated concentrations of total PCBs and specifically congeners 138, 153, and 180 compared to controls, whereas PCB concentrations in males were not significantly different between control and Parkinson's disease groups. In a separate population of women (Nun Study) who had no clinical signs or symptoms of PD, elevated concentrations total PCB and congeners 138, 153 and 180 were also observed in post-mortem brain tissue exhibiting moderate nigral depigmentation compared to subjects with mild or no depigmentation. These quantitative data demonstrate an association between brain PCB levels and Parkinson's disease-related pathology. Furthermore, these data support epidemiological and laboratory studies
5. Association between polychlorinated biphenyls and Parkinson’s disease neuropathology
Science.gov (United States)
Hatcher-Martin, Jaime M.; Gearing, Marla; Steenland, Kyle; Levey, Allan I.; Miller, Gary W.; Pennell, Kurt D.
2012-01-01
Polychlorinated biphenyls (PCBs) are synthetic chemicals primarily used as coolants and insulators in electrical equipment. Although banned for several decades, PCBs continue to exist in the environment because of their long half-life, continued presence in items produced before the ban, and poor disposal practices. Epidemiological and experimental studies have identified exposure to PCBs as a potential risk factor for Parkinson’s disease, perhaps more so in females. The objective of this work was to examine the association between PCB levels in post-mortem human brain tissue and the diagnosis of Parkinson’s disease, as well as the degree of nigral depigmentation. We also sought to determine if this association was more significant when patients were stratified by sex. Post-mortem brain samples from control patients and those diagnosed with Parkinson’s disease were obtained from the Emory University Brain Bank and from the Nun Study. Concentrations of eight prevalent PCB congeners were extracted from post-mortem brain tissue and analyzed using gas chromatography-mass spectrometry. PCB congeners 153 and 180 were significantly elevated in the brains of Parkinson’s disease patients. When stratified by sex, the female Parkinson’s disease group demonstrated significantly elevated concentrations of total PCBs and specifically congeners 138, 153, and 180 compared to controls, whereas PCB concentrations in males were not significantly different between control and Parkinson’s disease groups. In a separate population of women (Nun Study) who had no clinical signs or symptoms of PD, elevated concentrations total PCB and congeners 138, 153 and 180 were also observed in post-mortem brain tissue exhibiting moderate nigral depigmentation compared to subjects with mild or no depigmentation. These quantitative data demonstrate an association between brain PCB levels and Parkinson’s disease-related pathology. Furthermore, these data support epidemiological and
6. Immunotoxicity Monitoring in a Population Exposed to Polychlorinated Biphenyls
Directory of Open Access Journals (Sweden)
Hajo Haase
2016-03-01
Full Text Available The relationship between polychlorinated biphenyl (PCB burden and several indicators of immune function was investigated as part of the HELPcB (Health Effects in High-Level Exposure to PCB program, offering bio-monitoring to workers, relatives, and neighbors exposed to PCBs by a German transformers and capacitors recycling company. The present retrospective observational study evaluates the correlation of plasma levels of total PCBs, five indicator congeners (28, 101, 138, 153, 180, and seven dioxin-like congeners (105, 114, 118, 156, 157, 167, 189 with several parameters of immune function. The cross-sectional study was performed immediately after the end of exposure (258 subjects, and one (218 subjects, and two (177 subjects years later. At the first time point, measurements showed significant positive correlation between congeners with low to medium chlorination and the relative proportion of CD19 positive B-cells among lymphocytes, as well as a negative correlation of PCB114 with serum IgM, and of PCB 28 with suppressor T-cell and NK-cell numbers. Congeners with a high degree of chlorination, in particular PCB157 and 189, were positively associated with expression of the activation marker CD25 on T-cells in the cohort of the second time point. No associations between PCB levels and IFN-y production by T-cells and killing by NK-cells were found. In conclusion, there were several effects on the cellular composition of adaptive immunity, affecting both T- and B-cells. However, the values were not generally outside the reference ranges for healthy adult individuals and did not indicate overt functional immunodeficiency, even in subjects with the uppermost PCB burden.
7. Spermaturia and serum hormone concentrations at the age of puberty in boys prenatally exposed to polychlorinated biphenyls
DEFF Research Database (Denmark)
Mol, Nanette M; Sørensen, Nicolina; Weihe, Pal
2002-01-01
To determine whether prenatal exposure to polychlorinated biphenyls (PCBs) with possible hormone-disrupting effects is capable of affecting sexual differentiation in boys at the age of puberty.......To determine whether prenatal exposure to polychlorinated biphenyls (PCBs) with possible hormone-disrupting effects is capable of affecting sexual differentiation in boys at the age of puberty....
8. Synthesis, radiosynthesis, in vitro and preliminary in vivo evaluation of biphenyl carboxylic and hydroxamic matrix metalloproteinase (MMP) inhibitors as potential tumor imaging agents
International Nuclear Information System (INIS)
Oltenfreiter, Ruth; Staelens, Ludovicus; Hillaert, Ulrik; Heremans, An; Noel, Agnes; Frankenne, Francis; Slegers, Guido
2005-01-01
Excess matrix degradation is one of the hallmarks of cancer and is an important factor in the process of tumor progression. It is implicated in invasion, metastasis, growth, angiogenesis and migration. Many characteristics of matrix metalloproteinases (MMPs) make them attractive therapeutic and diagnostic targets. MMP expression is upregulated at the tumor site, with localization of activity in the tumor or the surrounding stroma, providing a target for medical imaging techniques. Radioiodinated carboxylic and hydroxamic MMP inhibitors 2-(4'-[ 123 I] iodo-biphenyl-4-sulfonylamino)-3-methyl-butyric acid (9) and 2-(4'-[ 123 I] iodo-biphenyl-4-sulfonylamino)-3-methyl-butyramide (11), their unlabelled standards and precursors were synthesized. Radioiodination was conducted by electrophilic aromatic substitution of the tributylstannyl precursors and resulted in radiochemical yields of 70+/-5% (n=6) and 60+/-5% (n=4), respectively. In vitro zymography and enzyme assays showed for both hydroxamic acid and carboxylic acid compounds a good inhibition activity and a high selectivity for MMP-2. In vivo biodistribution in NMRI mice showed no long-term accumulation in organs and the possibility to accumulate in the tumor in a later phase of this study
9. Synthesis, radiosynthesis, in vitro and preliminary in vivo evaluation of biphenyl carboxylic and hydroxamic matrix metalloproteinase (MMP) inhibitors as potential tumor imaging agents
Energy Technology Data Exchange (ETDEWEB)
Oltenfreiter, Ruth [Laboratory of Radiopharmacy, Ghent University, Harelbekestraat 72, 9000 Ghent (Belgium)]. E-mail: ruth.oltenfreiter@ugent.be; Staelens, Ludovicus [Laboratory of Radiopharmacy, Ghent University, Harelbekestraat 72, 9000 Ghent (Belgium); Hillaert, Ulrik [Laboratory for Medicinal Chemistry, Ghent University, Harelbekestraat 72, 9000 Ghent (Belgium); Heremans, An; Noel, Agnes [Laboratory of Tumor and Developmental Biology, University of Liege, Sart-Tilman, Liege (Belgium); Frankenne, Francis [Laboratory of Tumor and Developmental Biology, University of Liege, Sart-Tilman, Liege (Belgium); Slegers, Guido [Laboratory of Radiopharmacy, Ghent University, Harelbekestraat 72, 9000 Ghent (Belgium)
2005-06-01
Excess matrix degradation is one of the hallmarks of cancer and is an important factor in the process of tumor progression. It is implicated in invasion, metastasis, growth, angiogenesis and migration. Many characteristics of matrix metalloproteinases (MMPs) make them attractive therapeutic and diagnostic targets. MMP expression is upregulated at the tumor site, with localization of activity in the tumor or the surrounding stroma, providing a target for medical imaging techniques. Radioiodinated carboxylic and hydroxamic MMP inhibitors 2-(4'-[{sup 123}I] iodo-biphenyl-4-sulfonylamino)-3-methyl-butyric acid (9) and 2-(4'-[{sup 123}I] iodo-biphenyl-4-sulfonylamino)-3-methyl-butyramide (11), their unlabelled standards and precursors were synthesized. Radioiodination was conducted by electrophilic aromatic substitution of the tributylstannyl precursors and resulted in radiochemical yields of 70+/-5% (n=6) and 60+/-5% (n=4), respectively. In vitro zymography and enzyme assays showed for both hydroxamic acid and carboxylic acid compounds a good inhibition activity and a high selectivity for MMP-2. In vivo biodistribution in NMRI mice showed no long-term accumulation in organs and the possibility to accumulate in the tumor in a later phase of this study.
10. Novel metal-organic and supramolecular 3D frameworks constructed from flexible biphenyl-2,5,3‧-tricarboxylate blocks: Synthesis, structural features and properties
Science.gov (United States)
You, Ao; Li, Yu; Zhang, Ze-Min; Zou, Xun-Zhong; Gu, Jin-Zhong; Kirillov, Alexander M.; Chen, Jin-Wei; Chen, Yun-Bo
2017-10-01
Biphenyl-2,5,3‧-tricarboxylic acid (H3L) was selected as an unexplored tricarboxylate building block and applied for the hydrothermal synthesis of three novel coordination compounds, namely a 0D tetramer [Co4(HL)2(μ3-HL)2(phen)6(H2O)2]·3H2O (1) and two 3D metal-organic frameworks (MOFs) [Cd3(μ5-L)(μ6-L)(py)(μ-H2O)2(H2O)]n·H2O (2) and [Zn3(μ4-L)2(2,2‧-bpy)(μ-4,4‧-bpy)]n·2H2O (3). These products were easily generated in aqueous medium from the corresponding metal(II) chlorides, H3L, and various N-donor ancillary ligands, selected from 1,10-phenanthroline (phen), pyridine (py), 2,2‧-bipyridine (2,2‧-bpy), and 4,4‧-bipyridine (4,4‧-bpy). Compounds 1-3 were isolated as stable crystalline solids and were fully characterized by IR and UV-vis spectroscopy, elemental, thermogravimetric (TGA), powder (PXRD) and single-crystal X-ray diffraction analyses. Compound 1 possesses a discrete tetracobalt(II) structure, which is extended into a 3D H-bonded network with the pcu topology. In contrast, MOF 2 discloses a very complex trinodal 4,5,12-connected net with an undocumented topology, while MOF 3 features the nce/I topological framework. The magnetic (for 1) and luminescence (for 2 and 3) properties were also studied and discussed. The present study thus widens a still very limited family of metal-organic and supramolecular frameworks driven by flexible biphenyl-2,5,3‧-tricarboxylate building blocks.
11. Organolanthanoid compounds
International Nuclear Information System (INIS)
Schumann, H.
1984-01-01
Up to little more than a decade ago organolanthanoid compounds were still a curiosity. Apart from the description of an isolated number of cyclopentadienyl and indenyl derivatives, very few significant contributions had been made to this interesting sector of organometallic chemistry. However, subsequent systematic studies using modern preparative and analytical techniques, together with X-ray single crystal structure determinations, enabled the isolation and characterization of a large number of very interesting homoleptic and heteroleptic compounds in which the lanthanoid is bound to hydrogen, to substituted or unsubstituted cyclopentadienyl groups, to allyl or alkynyl groups, or even to phosphorus ylides, trimethylsilyl, and carbonylmetal groups. These compounds, which are all extremely sensitive to oxygen and water, open up new possibilities in the field of catalysis and have great potential in organic synthesis - as recent studies with pentamethylcyclopentadienyl derivatives, organolanthanoid(II) compounds, and hexamethyllanthanoid complexes have already shown. (orig.) [de
12. antistress and antimicrobial studies of biphenyl chalcone derivatives
African Journals Online (AJOL)
C. G. Darshan Raj, B. K. Sarojini, E. S. Sindhu Priya, M. T. Hassan Khan, C.Srinivas, P.S Manjula
characterized and evaluated for in vitro anti oxidant through chemical antioxidant ... bacteria. An in silico docking of the newly synthesized compounds to ..... dried and recrystallized from ethanol and % yield and meting point were noted [12].
13. Foetal uptake of coplanar polychlorinated biphenyl (PCB) congeners in mice
International Nuclear Information System (INIS)
Darnerud, P.O.; Sinjari, T.; Joensson, C.J.
1996-01-01
Earlier studies have shown that the Ah-receptor binding polychlorinated biphenyl (PCB) congener 3,3',4,4'-tetrachlorobiphenyl (IUPAC number CB-77) accumulated as hydroxy and methylsulphone metabolites in late gestational mice foetuses. In the present paper the foetal accumulation potential in mice of other dioxin-like PCB congeners was studied: 3,3'4,4',4-pentachlorobiphenyl, 3,3'4,4'5,5'-hexachlorobiphenyl and 2,3,3',4,4'-pentachlorobiphenyl (IUPAC numbers CB-126, CB-169, CB-105, to some extent dioxin-like) were compared to results of CB-77 (all congeners 14 C-labelled and in equimolar doses (2.0 μmol/kg body wt.)). CB-77 resulted in the comparatively strongest foetal 14 C-accumulation, when measured in plasma or whole body homogenate four days after administration (day 17 of pregnancy); the plasma 14 C-values (calculated as pmol/g wet wt.) were 760, 130, 60 and 40 for CB-77, -126, 105 and -169, respectively, and the CB-77 derived radioactivity in the foetal compartment was 3.6% of administered dose (i.e. a considerable portion of the remaining maternal body radioactivity). Thin-layer chromatography (TLC) results, suggesting extensive CB-77 metabolism and foetal metabolite uptake, support earlier findings. The effects of CB-77 and CB-169 on foetal 7-ethoxyresorufin-O-deethylase (EROD) activities (day 17 of gestation; two days after 5 mg/kg body wt. dose (14.0-17.0 μmol/kg body wt.)) was about 20 times lower than of CB-126. In the dam, high radioactivity levels were observed int he liver and fat (highest concentrations found in CB-126 and CB-105, respectively). Strain comparison - foetal 14 C-uptake (four days after administration of CB-77) in C57BL mice was almost five times higher than in NMRI - may be correlated to earlier observed differences in EROD activities between these strains. The present results indicate that congener and strain differences exist regarding both foetal and maternal distribution patterns of coplanar PCB congeners and point out the
14. Plasma polychlorinated biphenyl concentrations and immune function in postmenopausal women
International Nuclear Information System (INIS)
Spector, June T.; De Roos, Anneclaire J.; Ulrich, Cornelia M.; Sheppard, Lianne; Sjoedin, Andreas; Wener, Mark H.; Wood, Brent
2014-01-01
Background: Polychlorinated biphenyl (PCB) exposure has been associated with non-Hodgkin lymphoma in several studies, and the immune system is a potential mediator. Objectives: We analyzed associations of plasma PCBs with immune function measures. We hypothesized that higher plasma PCB concentrations are associated with lower immune function cross-sectionally, and that increases in PCB concentrations over a one year period are associated with decreases in immune function. Methods: Plasma PCB concentrations and immune function [natural killer (NK) cell cytotoxicity and PHA-induced T-lymphocyte proliferation (PHA-TLP)] were measured at baseline and one year in 109 postmenopausal overweight women participating in an exercise intervention study in the Seattle, Washington (USA) area. Mixed models, with adjustment for body mass index and other potential confounders, were used to estimate associations of PCBs with immune function cross-sectionally and longitudinally. Results: Associations of PCBs with immune function measures differed across groups of PCBs (e.g., medium- and high-chlorinated and dioxin-like [mono-ortho-substituted]) and by the time frame for the comparison (cross-sectional vs. longitudinal). Higher concentrations of medium- and high-chlorinated PCBs were associated with higher PHA-TLP cross-sectionally but not longitudinally. The mean decrease in 0.5 µg/mL PHA-TLP/50.0 pmol/g-lipid increase in dioxin-like PCBs over one year was 51.6 (95% confidence interval 2.7, 100.5; P=0.039). There was no association between plasma PCBs and NK cytotoxicity. Conclusions: These results do not provide strong evidence of impaired cellular immunity from PCB exposure. Larger longitudinal studies with greater variability in PCB exposures are needed to further examine temporal associations of PCBs with immune function. - Highlights: • Plasma PCBs and immune function were measured in 109 women at baseline and one year. • Immune measures included T lymphocyte proliferation
15. Plasma polychlorinated biphenyl concentrations and immune function in postmenopausal women
Energy Technology Data Exchange (ETDEWEB)
Spector, June T., E-mail: spectj@uw.edu [Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, 4225 Roosevelt Way NE, Seattle, WA 98105 (United States); Department of Medicine, School of Medicine, University of Washington, Seattle, WA (United States); De Roos, Anneclaire J., E-mail: ajd335@drexel.edu [Epidemiology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N, P.O. Box 19024, Seattle, WA 98109 (United States); Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA (United States); Ulrich, Cornelia M., E-mail: neli.ulrich@nct-heidelberg.de [Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA (United States); Cancer Prevention Program, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N, P.O. Box 19024, Seattle, WA 98109 (United States); National Center for Tumor Diseases and German Cancer Research Center, Heidelberg (Germany); Sheppard, Lianne, E-mail: sheppard@uw.edu [Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, 4225 Roosevelt Way NE, Seattle, WA 98105 (United States); Department of Biostatistics, School of Public Health, University of Washington, Seattle, WA (United States); Sjoedin, Andreas, E-mail: asjodin@cdc.gov [National Center for Environmental Health, CDC, 4770 Buford Highway NE, Atlanta, GA 30341 (United States); Wener, Mark H., E-mail: wener@u.washington.edu [Department of Medicine, School of Medicine, University of Washington, Seattle, WA (United States); Wood, Brent, E-mail: woodbl@u.washington.edu [Department of Medicine, School of Medicine, University of Washington, Seattle, WA (United States); and others
2014-05-01
Background: Polychlorinated biphenyl (PCB) exposure has been associated with non-Hodgkin lymphoma in several studies, and the immune system is a potential mediator. Objectives: We analyzed associations of plasma PCBs with immune function measures. We hypothesized that higher plasma PCB concentrations are associated with lower immune function cross-sectionally, and that increases in PCB concentrations over a one year period are associated with decreases in immune function. Methods: Plasma PCB concentrations and immune function [natural killer (NK) cell cytotoxicity and PHA-induced T-lymphocyte proliferation (PHA-TLP)] were measured at baseline and one year in 109 postmenopausal overweight women participating in an exercise intervention study in the Seattle, Washington (USA) area. Mixed models, with adjustment for body mass index and other potential confounders, were used to estimate associations of PCBs with immune function cross-sectionally and longitudinally. Results: Associations of PCBs with immune function measures differed across groups of PCBs (e.g., medium- and high-chlorinated and dioxin-like [mono-ortho-substituted]) and by the time frame for the comparison (cross-sectional vs. longitudinal). Higher concentrations of medium- and high-chlorinated PCBs were associated with higher PHA-TLP cross-sectionally but not longitudinally. The mean decrease in 0.5 µg/mL PHA-TLP/50.0 pmol/g-lipid increase in dioxin-like PCBs over one year was 51.6 (95% confidence interval 2.7, 100.5; P=0.039). There was no association between plasma PCBs and NK cytotoxicity. Conclusions: These results do not provide strong evidence of impaired cellular immunity from PCB exposure. Larger longitudinal studies with greater variability in PCB exposures are needed to further examine temporal associations of PCBs with immune function. - Highlights: • Plasma PCBs and immune function were measured in 109 women at baseline and one year. • Immune measures included T lymphocyte proliferation
16. Lactational transfer of mercury and polychlorinated biphenyls in polar bears.
Science.gov (United States)
Knott, Katrina K; Boyd, Daryle; Ylitalo, Gina M; O'Hara, Todd M
2012-07-01
We examined concentrations of total mercury (tHg, inorganic and methylated forms) and polychlorinated biphenyls (PCBs) in blood and milk from free-ranging Southern Beaufort-Chukchi Sea polar bears (Ursus maritimus) to assess maternal transfer of contaminants during lactation and the potential health risk to nursing young. Concentrations of contaminants in the blood of dependent and juvenile animals (ages 1-5 years) ranged from 35.9 to 52.2 μg kg(-1) ww for tHg and 13.9 to 52.2 μg kg(-1) ww (3255.81-11067.79 μg kg(-1) lw) for ΣPCB(7)s, similar to those of adult females, but greater than adult males. Contaminant concentrations in milk ranged from 5.7 to 71.8 μg tHg kg(-1)ww and 160 to 690 μg ΣPCB(11)s kg(-1) ww (547-5190 μg kg(-1) lw). The daily intake levels for tHg by milk consumption estimated for dependent young were below the tolerable daily intake level (TDIL) of tHg established for adult humans. Although the daily intake levels of PCBs through milk consumption for cubs of the year exceeded the TDIL thresholds, calculated dioxin equivalents for PCBs in milk were below adverse physiological thresholds for aquatic mammals. Relatively high concentrations of non-dioxin like PCBs in polar bear milk and blood could impact endocrine function of Southern Beaufort-Chukchi Sea polar bears, but this is uncertain. Transfer of contaminants during mid to late lactation likely limits bioaccumulation of dietary contaminants in female polar bears during spring. As polar bears respond to changes in their arctic sea ice habitat, the adverse health impacts associated with nutritional stress may be exacerbated by tHg and PCBs exposure, especially in ecologically and toxicologically sensitive polar bear cohorts such as reproductive females and young. Copyright © 2012. Published by Elsevier Ltd.
17. Multipurpose Compound
Science.gov (United States)
1983-01-01
Specially formulated derivatives of an unusual basic compound known as Alcide may be the answer to effective treatment and prevention of the disease bovine mastitis, a bacterial inflammation of a cow's mammary gland that results in loss of milk production and in extreme cases, death. Manufactured by Alcide Corporation the Alcide compound has killed all tested bacteria, virus and fungi, shortly after contact, with minimal toxic effects on humans or animals. Alcide Corporation credits the existence of the mastitis treatment/prevention products to assistance provided the company by NERAC, Inc.
18. THE 2005 WORLD HEALTH ORGANIZATION RE-EVALUATION OF HUMAN AND MAMMALIAN TOXIC EQUIVALENCY FACTORS FOR DIOXINS AND DIOXIN-LIKE COMPOUNDS
Science.gov (United States)
In June 2005 a WHO-IPCS expert meeting was held in Geneva during which the toxic equivalency factors (TEFs) for dioxin like compounds, including some polychlorinated biphenyls (PCBs), were re-evaluated. For this re-evaluation process the refined TEF database recently published by...
19. Neurological condition in 18-month-old children perinatally exposed to polychlorinated biphenyls and dioxins
NARCIS (Netherlands)
Huisman, M; KoopmanEsseboom, C; vanderPaauw, CG; Tuinstra, LGMT; Fidler, [No Value; WeisglasKuperus, N; Sauer, PJJ; Boersma, ER; Touwen, BCL
1995-01-01
The neurological optimality of 418 Dutch children was evaluated at the age of 18 months, in order to determine whether prenatal and breast milk mediated exposure to polychlorinated biphenyls (PCBs) and dioxins affected neurological development, Half of the infants were breast-fed, the other half
20. Polychlorinated biphenyl-induced alterations of thyroid hormone homeostasis and brain development in the rat
NARCIS (Netherlands)
Morse, D.C.
1995-01-01
Introduction
The work described in this thesis was undertaken to gain insight in the processes involved in the developmental neurotoxicity of polychlorinated biphenyls. It has been previously hypothesized that the alteration of thyroid hormone status by PCBs may
1. Preparation of plants containing bacterial enzyme for degradation of polychlorinated biphenyls
Czech Academy of Sciences Publication Activity Database
Francová, K.; Surá, M.; Macek, Tomáš; Szekeres, M.; Bancos, S.; Demnerová, K.; Sylvestre, M.; Macková, M.
2003-01-01
Roč. 12, č. 3 (2003), s. 309-313 ISSN 1018-4619 Institutional research plan: CEZ:AV0Z4055905 Keywords : transgenic plants * polychlorinated biphenyls * phytoremediation Subject RIV: DK - Soil Contamination ; De-contamination incl. Pesticides Impact factor: 0.325, year: 2003
2. Polychlorinated biphenyls in adipose tissue, liver, and brain from nine stillborns of varying gestational ages
NARCIS (Netherlands)
Huisman, M; Muskiet, FAJ; Van Der Paauw, CG; Essed, CE; Boersma, ER
We analyzed polychlorinated biphenyls (PCBs) in s.c. adipose tissue, liver, and brain of nine fetuses who died in utero. Their median (range) gestational ages and birth weights were 34 (17-40) wk and 2050 (162-3225) g. Three fetuses were small for gestational age. The levels of PCB congener nos.
3. New Biochemical Pathway for Biphenyl Degradation in Plants: Structural, Mechanistic and Biotechnological Aspects
International Nuclear Information System (INIS)
Pacios, L. F.; Campos, V. M.; Merino, I.; Gomez, L.
2009-01-01
Polychlorinated biphenyls (PVBs) and other structurally-related xenobiotics are amongst the most relevant organic pollutants known today. while some bacterial species can metabolize PCBs, with varying efficiency, no catabolic pathways have yet been described in plants. This is so despite the great potential of (at least some) plant species for soil and groundwater decontamination, a technology known as phyto remediation. (Author)
4. Predicting the bioaccumulation of polyaromatic hydrocarbons and polychlorinated biphenyls in benthic animals in sediments
NARCIS (Netherlands)
Tuikka, A. I.; Leppänen, M. T.; Akkanen, J.; Sormunen, A. J.; Leonards, P. E.G.; van Hattum, B.; van Vliet, L. A.; Brack, W.; Smedes, F.; Kukkonen, J. V.K.
2016-01-01
There were two main objectives in this study. The first was to compare the accuracy of different prediction methods for the chemical concentrations of polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the organism, based on the measured chemical concentrations existing in
5. Effects of black carbon on bioturbination-induced benthic fluxes of polychlorinated biphenyls
NARCIS (Netherlands)
Koelmans, A.A.; Jonker, M.T.O.
2011-01-01
It is unknown whether carbonaceous geosorbents, such as black carbon (BC) affect bioturbation by benthic invertebrates, thereby possibly affecting sediment–water exchange of sediment-bound contaminants. Here, we assess the effects of oil soot on polychlorinated biphenyl (PCB) mass transfer from
6. Contamination of free-range chicken eggs with dioxins and dioxin-like polychlorinated biphenyls
NARCIS (Netherlands)
Schoeters, G.; Hoogenboom, L.A.P.
2006-01-01
Dioxins and dioxin-like (DL) polychlorinated biphenyls (PCB) are persistent organic pollutants that enter the body mainly by food intake. A small margin exists between current exposure levels in the human population and the levels causing biological effects. Therefore, stringent control of
7. Induction of monooxygenation in rainbow trout by polybrominated biphenyls: a comparative study.
Science.gov (United States)
Elcombe, C R; Lech, J J
1978-01-01
Two commercial polychlorinated biphenyl mixtures (Aroclor 1254 and Aroclor 1242) and one polybrominated biphenyl mixture (FireMaster BP-6) were examined for their abilities to induce hepatic microsomal monooxygenation in rainbow trout (Salmo gairdneri). Pretreatment of rainbow trout with Aroclors 1254 and 1242 (150 mg/kg IP) resulted in an approximate 10-fold induction of arylhydrocarbon (benzo[a]pyrene) hydroxylation, ethoxycoumarin-O-deethylation and ethoxyresorufin-O-deethylation within 7 days after injection. These enzyme activities remained elevated above control values for at least 2-3 weeks. Administration of FireMaster BP-6 (150 mg/kg IP) also resulted in an induction of several monooxygenase activities. Arylhydrocarbon (benzo[a]pyrene) hydroxylation, ethoxycoumarin-O-deethylation and ethoxyresorufin-O-deethylation were increased by 6-, 3,- and 25-fold, respectively. Only the latter two activities remained elevated two weeks post-injection. Ethylmorphine-N-demethylation was unaffected by the polyhalogenated biphenyls. Significant increases in P-450 hemoprotein were not observed after pretreatment with any of the polyhalogenated biphenyls studied. PMID:209992
8. Library of biphenyl privileged substructures using a safety-catch linker approach
DEFF Research Database (Denmark)
Severinsen, Rune; Bourne, Gregory T; Tran, Tran T
2008-01-01
A biphenyl privileged structure library containing three attachment points were synthesized using a catechol-based safety-catch linker strategy. The method requires the attachment of a bromo-acid to the linker, followed by a Pd-catalyzed Suzuki cross-coupling reaction. Further derivatization...
9. ANALYSIS OF SOIL AND DUST SAMPLES FOR POLYCHLORINATED BIPHENYLS BY ENZYME LINKED IMMUNOSORBENT ASSAY (ELISA)
Science.gov (United States)
An inhibition enzyme-linked immunosorbent assay (ELISA) was used to determine polychlorinated biphenyls (PCBs) in house dust and soil. Soil and house dust samples were analyzed for PCB by both gas chromatography/electron capture detection (GC/ECD) and ELISA methods. A correlati...
10. [Determination of biphenyl ether herbicides in water using HPLC with cloud-point extraction].
Science.gov (United States)
He, Cheng-Yan; Li, Yuan-Qian; Wang, Shen-Jiao; Ouyang, Hua-Xue; Zheng, Bo
2010-01-01
To determine residues of multiple biphenyl ether herbicides simultaneously in water using high performance liquid chromatography (HPLC) with cloud-point extraction. The residues of eight biphenyl ether herbicides (including bentazone, fomesafen, acifluorfen, aclonifen, bifenox, fluoroglycofenethy, nitrofen, oxyfluorfen) in water samples were extracted with cloud-point extraction of Triton X-114. The analytes were separated and determined using reverse phase HPLC with ultraviolet detector at 300 nm. Optimized conditions for the pretreatment of water samples and the parameters of chromatographic separation applied. There was a good linear correlation between the concentration and the peak area of the analytes in the range of 0.05-2.00 mg/L (r = 0.9991-0.9998). Except bentazone, the spiked recoveries of the biphenyl ether herbicides in the water samples ranged from 80.1% to 100.9%, with relative standard deviations ranging from 2.70% to 6.40%. The detection limit of the method ranged from 0.10 microg/L to 0.50 microg/L. The proposed method is simple, rapid and sensitive, and can meet the requirements of determination of multiple biphenyl ether herbicides simultaneously in natural waters.
11. Allee effect in polar bears: A potential consequence of polychlorinated biphenyl contamination.
Czech Academy of Sciences Publication Activity Database
Pavlová, Viola; Nabe-Nielsen, J.; Dietz, R.; Sonne, C.; Grimm, V.
2016-01-01
Roč. 283, č. 1843 (2016), č. článku 20161883. ISSN 0962-8452 Institutional support: RVO:60077344 Keywords : allee effect * polychlorinated biphenyls * polar bears * male reproduction Subject RIV: EH - Ecology, Behaviour Impact factor: 4.940, year: 2016
12. Uptake of polychlorinated biphenyls and organochlorine pesticides from soil and air into radishes (Raphanus sativus)
DEFF Research Database (Denmark)
Mikes, Ondrej; Cupr, P.; Trapp, Stefan
2009-01-01
Uptake of organochlorine pesticides and polychlorinated biphenyls from soil and air into radishes was measured at a heavily contaminated field site. The highest contaminant concentrations were found for DDT and its metabolites, and for beta-hexachlorocyclohexane. Bioconcentration factor (BCF, def...
13. Crystallographic identification of an unexpected by-product in an Ullman's reaction toward biphenyls: 1-(4-hexyloxy-3-hydroxyphenyl)ethanone.
Science.gov (United States)
Manzano, Veronica E; Baggio, Ricardo; Cukiernik, Fabio D
2015-11-01
The synthesis of 3,3'-diacetoxy-4,4'-bis(hexyloxy)biphenyl following the nickel-modified Ullmann reaction yielded a by-product which was identified successfully by crystallographic analysis as 1-(4-hexyloxy-3-hydroxyphenyl)ethanone, C14H20O3. This unexpected nonbiphenyl by-product exhibited IR, (1)H NMR, (13)C NMR and COSY (correlation spectroscopy) spectra fully consistent with the proposed structure. The compound crystallized in the orthorombic Pbca space group, with two independent formula units in the asymmetric unit (one of which was slightly disordered), and showed a supramolecular architecture in which molecules linked by hydroxy-ethanone O-H···O interactions are organized in columns separated by the aliphatic tails.
14. Ultrathin-shell boron nitride hollow spheres as sorbent for dispersive solid-phase extraction of polychlorinated biphenyls from environmental water samples.
Science.gov (United States)
Fu, Meizhen; Xing, Hanzhu; Chen, Xiangfeng; Chen, Fan; Wu, Chi-Man Lawrence; Zhao, Rusong; Cheng, Chuange
2014-11-21
Boron nitride hollow spheres with ultrathin-shells were synthesized and used as sorbents for dispersive solid-phase extraction of aromatic pollutants at trace levels from environmental water samples. Polychlorinated biphenyls (PCBs) were selected as target compounds. Sample quantification and detection were performed by gas chromatography-tandem mass spectrometry. Extraction parameters influencing the extraction efficiency were optimized through response surface methodology using the Box-Behnken design. The proposed method achieved good linearity within the concentration range of 0.15-250 ng L(-1) PCBs, low limits of detection (0.04-0.09 ng L(-1), S/N=3:1), good repeatability of the extractions (relative standard deviation, spring waters were analyzed using the developed method. Results demonstrated that the hexagonal boron nitride-based material has significant potential as a sorbent for organic pollutant extraction from environmental water samples. Copyright © 2014 Elsevier B.V. All rights reserved.
15. Polychlorinated biphenyls pattern analysis: Potential nondestructive biomarker in vertebrates for exposure to cytochrome P450-inducing organochlorines
Energy Technology Data Exchange (ETDEWEB)
Brink, N.W. van den; Ruiter-Dijkman, E.M. De; Broekhuizen, S.; Reijnders, P.J.H.; Bosveld, A.T.C.
2000-03-01
Biomarkers are valuable instruments to assess the risks from exposure of organisms to organochlorines. In general, however, these biomarkers are either destructive to the animal of interest or extremely difficult to obtain otherwise. In this paper, the authors present a nondestructive biomarker for exposure to cytochrome P450-inducing organochlorines. This marker is based on a pattern analysis of metabolizable and nonmetabolizable polychlorinated biphenyl (PCB) congeners, which occur in several kinds of tissues (and even blood) that can be obtained without serious effects on the organism involved. The fraction of metabolizable PCB congeners is negatively correlated with exposure to PCBs, which are known to induce specific P450 isoenzymes. This relation can be modeled by a logistic curve, which can be used to define critical levels of exposure. In addition, this method creates an opportunity to analyze biomarker responses in archived tissues stored at standard freezing temperatures ({minus}20 C), at which responses to established biomarkers deteriorate. Furthermore, this method facilitates attribution of the enzyme induction to certain classes of compounds.
16. Unusual polymorphism in new bent-shaped liquid crystals based on biphenyl as a central molecular core
Directory of Open Access Journals (Sweden)
Anna Kovářová
2014-04-01
Full Text Available Bent-shaped mesogens possessing a biphenyl as a central core have been synthesized and the role of the terminal chain and the orientation of the ester as a linkage group have been investigated. For the studied molecular core we have established that both parameters play an important role for the mesomorphic properties. The polyfluoroalkyl terminal chain supports the formation of mesophases, and the introduction of a chiral lactate terminal chain destabilizes mesophases for the first type of mutual orientation of ester groups, attached to the central core. On the contrary, for the opposite orientation of esters, the terminal chain has no effect on the mesomorphic properties, and columnar phases have been found for all compounds. A unique phase sequence has been found for the mesogen with the fluorinated chain. A generalized tilted smectics, SmCG, have been observed in a temperature interval between two different lamellar SmCP phases and characterized by X-ray and dielectric measurements. The dielectric spectroscopy data are unique and presented for the first time in the SmCG phase providing new information about the molecular dynamics.
17. Levels, distribution and air-soil exchange fluxes of polychlorinated biphenyls (PCBs) in the environment of Punjab Province, Pakistan.
Science.gov (United States)
Syed, Jabir Hussain; Malik, Riffat Naseem; Li, Jun; Zhang, Gan; Jones, Kevin C
2013-11-01
An initial survey of the concentrations of polychlorinated biphenyl (PCB) compounds in air and soils across industrial and agricultural areas of Punjab Province, Pakistan, was conducted from January to March 2011. The total concentration of all PCBs (31 PCBs) ranged from 34 to 389pgm(-3) in air and from 7 to 45ngg(-1) dry weight in soils, where both ranges were similar to the average ranges in other areas of the world. PCBs were elevated across industrial regions near urban and industrial sources. Consistently low air concentrations of PCBs at the agricultural sites suggest that they are less widespread or uniformly distributed in the Pakistani atmosphere. The calculated air and soil fugacity fraction values indicated that soils are a potential secondary source of PCBs in agricultural areas, whereas they are in equilibrium or atmospheric deposition in industrial and urban areas. TEQ concentrations of dioxin-like PCBs for soil samples met the Canadian standard. However, local authorities should address the human health threats from urban and industrial soils in Punjab Province, Pakistan. Copyright © 2013 Elsevier Inc. All rights reserved.
18. Predicting the bioaccumulation of polyaromatic hydrocarbons and polychlorinated biphenyls in benthic animals in sediments
Energy Technology Data Exchange (ETDEWEB)
Tuikka, A.I., E-mail: anitat@student.uef.fi [University of Eastern Finland, Department of Environmental and Biological Sciences, P.O. Box 111, FI-80101 Joensuu (Finland); Leppänen, M.T., E-mail: Matti.T.Leppanen@ymparisto.fi [Finnish Environment Institute, Laboratories/Research and Innovation Laboratory, P.O. Box 35, University of Jyväskylä, FI-40014 Jyväskylä (Finland); Akkanen, J., E-mail: jarkko.akkanen@uef.fi [University of Eastern Finland, Department of Environmental and Biological Sciences, P.O. Box 111, FI-80101 Joensuu (Finland); Sormunen, A.J., E-mail: Arto.Sormunen@mamk.fi [University of Eastern Finland, Department of Environmental and Biological Sciences, P.O. Box 111, FI-80101 Joensuu (Finland); Leonards, P.E.G., E-mail: pim.leonards@vu.nl [Institute for Environmental Studies, Vrije Universiteit Amsterdam, De Boelelaan 1087, 1081 HV Amsterdam (Netherlands); Hattum, B. van, E-mail: bert.vanhattum@deltares.nl [Institute for Environmental Studies, Vrije Universiteit Amsterdam, De Boelelaan 1087, 1081 HV Amsterdam (Netherlands); Vliet, L.A. van, E-mail: lavanvliet@hotmail.com [Ministry of Transport, Public Works and Water Management, National Institute for Coastal and Marine Management/RIKZ, P.O. Box 207, 9750 AE Haren (Netherlands); Brack, W., E-mail: werner.brack@ufz.de [Helmholtz Centre for Environmental Research - UFZ, Department of Effect-Directed Analysis, Permoserstraße 15, 04318 Leipzig (Germany); Smedes, F., E-mail: smedes@recetox.muni.cz [Ministry of Transport, Public Works and Water Management, National Institute for Coastal and Marine Management/RIKZ, P.O. Box 207, 9750 AE Haren (Netherlands); and others
2016-09-01
There were two main objectives in this study. The first was to compare the accuracy of different prediction methods for the chemical concentrations of polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the organism, based on the measured chemical concentrations existing in sediment dry matter or pore water. The predicted tissue concentrations were compared to the measured ones after 28-day laboratory test using oligochaeta worms (Lumbriculus variegatus). The second objective was to compare the bioaccumulation of PAHs and PCBs in the laboratory test with the in situ bioaccumulation of these compounds. Using the traditional organic carbon-water partitioning model, tissue concentrations were greatly overestimated, based on the concentrations in the sediment dry matter. Use of an additional correction factor for black carbon with a two-carbon model, significantly improved the bioaccumulation predictions, thus confirming that black carbon was important in binding the chemicals and reducing their accumulation. The predicted PAH tissue concentrations were, however, high compared to the observed values. The chemical concentrations were most accurately predicted from their freely dissolved pore water concentrations, determined using equilibrium passive sampling. The patterns of PCB and PAH accumulation in sediments for laboratory-exposed L. variegatus were similar to those in field-collected Lumbriculidae worms. Field-collected benthic invertebrates and L. variegatus accumulated less PAHs than PCBs with similar lipophilicity. The biota to sediment accumulation factors of PAHs tended to decrease with increasing sediment organic carbon normalized concentrations. The presented data yields bioconcentration factors (BCF) describing the chemical water-lipid partition, which were found to be higher than the octanol-water partition coefficients, but on a similar level with BCFs drawn from relevant literature. In conclusion, using the two-carbon model method
19. Radiological tracing for historical patterns of polychlorinated biphenyls in creek ecosystem
International Nuclear Information System (INIS)
Tiwari, M.; Bhangare, R.C.; Ajmal, P.Y.; Sahu, S.K.; Pandit, G.G.
2014-01-01
The marine sediments act like sink for most of the pollutants entering the aquatic environment. It becomes more critical in the case of creek ecosystem due to its landlocked and relatively stagnant nature. Various persistent organic pollutants (POPs) like polychlorinated biphenyls (PCBs) are brought into the creek in the form of dissolved and particulate fluxes from industrial effluents, sewerage discharge, urban runoff from the city, spillage, disposal and chemical weathering. PCBs cycle between sediment, water, air and soil. Studying the historical patterns of these toxic pollutants depositions in sediment cores have several applications. They throw light on the chronological inputs of the pollutants in the marine body. Natural radionuclides like 210 Pb act as tracers for determining the historical patterns of these pollutants in different sediment layers. Determining the activities of these radionuclides is useful for determining the age of sediment layers from the sedimentation rates. The unsupported 210 Pb activity of the Thane creek sediments was determined and modeled for assigning the age to different layers of the cores contaminated with PCBs. The unsupported activity of 210 Pb tracer was found to decrease with the increase in depth of the sediment layers. This pattern of the 210 Pb activity was used for determining the sedimentation rate and age of the core layers. The CRS model with 210 Pb activity traced the average sedimentation rate in Thane Creek to 0.67 cm/yr. This helped in labeling the age of formation of the deep core sediment layers. The vertical profile of different PCB congener concentrations in the core samples depicts a gradient from top to bottom, which indicates the influence of industrial contributions over the period. Peak concentrations for the congeners were observed at 13-24 depth, which indicates excessive loading of sediment with these compounds during 1970s (20-30 cm) which was the period of the maximum use and production of these
20. Exchange of polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) between air and a mixed pasture sward.
Science.gov (United States)
Barber, Jonathan L; Thomas, Gareth O; Bailey, Rebekah; Kerstiens, Gerhard; Jones, Kevin C
2004-07-15
To improve understanding of air-to-vegetation transfer of persistent organic pollutants (POPs), uptake and depuration of polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) between grass sward and air was investigated. Pasture swards were placed in fanned (2 m s(-1) wind speed) and unfanned conditions for a period of 20 days and sampled at intervals. Depuration was carried out after a short (4 days) and a long (14 days) exposure period. Prior to contamination, a mixed pasture sward at a semi-rural location contained sigmaPCN concentrations 15-20% of the sigmaPCB concentration. Uptake of both PCBs and PCNs was broadly linear in fanned and unfanned conditions over the 20-day period, i.e., the pasture did not reach equilibrium with the air. Uptake rates (fluxes) were greater under the fanned conditions. The difference in uptake rates between fanned and unfanned conditions increased with degree of chlorination for both PCBs and PCNs, ranging between a factor of 2 for tri-chlorinated PCBs and PCNs and a factor 5 for octa-chlorinated PCBs. Depuration results over the first hours were very scattered, showing an initial period of loss, followed by an increase in concentrations, possibly as a result of re-volatilization of PCBs from the soil in the trays, with consequent recapture by the overlying sward. Rapid clearance was observed over the following days, but depuration of PCBs and PCNs was still incomplete after 14 days, with 20% of the initial concentration of the sigmaPCBs and 10% of the sigmaPCNs retained by the sward. There was no difference in the proportion of POPs retained in the sward between the 4- and 14-day contamination treatments. POP-specific differences in the amount of compound "trapped" in leaves after contamination were observed. The results show that, although changes in the rate of air movement around a pasture have an effect on the uptake rate of POPs into the vegetation, plant-side resistance controls both the air-to-pasture and
1. Polymer compound
NARCIS (Netherlands)
1995-01-01
A Polymer compound comprising a polymer (a) that contains cyclic imidesgroups and a polymer (b) that contains monomer groups with a 2,4-diamino-1,3,5-triazine side group. According to the formula (see formula) whereby themole percentage ratio of the cyclic imides groups in the polymer compoundwith
2. Mesoionic Compounds
Organic Chemistry. Kamatak University,. Dharwad. Her research interests are synthesis, reactions and synthetic utility of sydnones. She is currently working on electrochemical and insecticidal/antifungal activities for some of these compounds. Keywords. Aromaticity, mesoionic hetero- cycles, sydnones, tandem re- actions.
3. Polychlorinated biphenyl in fish samples from Lagos Lagoon, Nigeria
African Journals Online (AJOL)
STORAGESEVER
2009-06-17
Jun 17, 2009 ... toxic chemical compounds consisting of 209 congeners. These persistent organic pollutants (POPs) have spread globally, and .... Extraction. Prior to extraction, the fish specimens were dissected and the ... The isolation of PCBs from the lipid matrix was done by solid phase ... Activated silica gel was loaded.
4. A Review on Polychlorinated Biphenyls (PCBs) and Polybrominated Diphenyl Ethers (PBDEs) in South Asia with a Focus on Malaysia.
Science.gov (United States)
Kaw, Han Yeong; Kannan, Narayanan
Malaysia is a developing country in Southeast Asia, with rapid industrial and economic growth. Speedy population growth and aggressive consumerism in the past five decades have resulted in environmental pollution issues, including products containing polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). PCBs and PBDEs are classified as persistent organic pollutants (POPs) by the Stockholm Convention due to their persistence, bioaccumulation in the environment and toxicity to humans and wildlife. These compounds are known to cause liver dysfunction, thyroid toxicity, developmental neuro-toxicity and possibly cancer. PCBs in air, mussels, pellets, seawater, fresh water, and human breast milk samples were analyzed in Malaysia, while studies on the pollution level of PBDEs in Malaysia were conducted on mussels, soils, leachate and sediment samples. PCBs in breast milk collected from Malaysia was the highest among Asian developing countries, with mean concentration of 80 ng/g lipid weight. On the other hand, the mean concentration of PCBs in mussels collected from Malaysia recorded the second lowest, with 56 ng/g and 89 ng/g lipid weight in two studies respectively. The concentrations of PBDEs in mussels taken from Malaysia fall in the range of 0.84-16 ng/g lipid weight, which is considerably low compared to 104.5 ng/g lipid weight in Philippines and 90.59 ng/g in Korea. Nevertheless, there are limited studies on these compounds in Malaysia, particularly there is no research on PBDEs in breast milk and sediment samples. This review will summarize the contamination levels of PCBs and PBDEs in different samples collected from Asian countries since 1988 until 2010 with a focus on Malaysia and will provide needed information for further research in this field.
5. Compound odontoma
Directory of Open Access Journals (Sweden)
2012-01-01
Full Text Available Odontomas have been extensively reported in the dental literature, and the term refers to tumors of odontogenic origin. Though the exact etiology is still unknown, the postulated causes include: local trauma, infection, inheritance and genetic mutation. The majority of the lesions are asymptomatic; however, may be accompanied with pain and swelling as secondary complaints in some cases. Here, we report a case of a compound odontome in a 14 year old patient.
6. Production of metabolites from chloro biphenyls by resting cells of Pseudomonas strain LB400 after growth on different carbon sources
International Nuclear Information System (INIS)
Billingsley, K.A.; Ward, O.P.
1999-01-01
The transformation of polychlorinated biphenyl (PCB), when exposed to microorganisms, into chlorobenzoic acid metabolites was studied. PCBs are widely used in electrical transformers and have become widely dispersed in the environment. A proposed system for clean up of PCBs involves the combined use of anaerobic reductive dehalogenation of highly chlorinated congeners followed by aerobic degradation of moderately chlorinated PCBs, mediated by oxidative ring attack. Much of this work focused on biphenyl-grown cells, in particular Pseudomonas strain LB400 grown on biphenyl, which contains a multicomponent enzyme system. It was shown that resting cells of Pseudomonas strain LB400, grown on glycerol or glucose, could also transform purified PCB congeners and mixtures of PCBs in Aroclors, however, transformation rates were less than those observed with biphenyl-grown cells. 29 refs., 2 tabs., 2 figs
7. Proof of concept for the use of macroinvertebrates as indicators of polychlorinated biphenyls (PCB) contamination in Lake Hartwell
Science.gov (United States)
The U.S. Environmental Protection Agency (EPA) has been conducting research to develop methods and tools for the evaluation of monitored natural recovery (MNR) of sediments contaminated with polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and other lega...
8. The reactivity of phenolic and non-phenolic residual kraft lignin model compounds with Mn(II)-peroxidase from Lentinula edodes.
Science.gov (United States)
Crestini, C; D'Annibale, A; Sermanni, G G; Saladino, R
2000-02-01
Three phenolic model compounds representing bonding patterns of residual kraft lignin were incubated with manganese peroxidase from Lentinula edodes. Extensive degradation of all the phenolic models, mainly occurring via side-chain benzylic oxidation, was observed. Among the tested model compounds the diphenylmethane alpha-5 phenolic model was found to be the most reactive, yielding several products showing oxidation and fragmentation at the bridging position. The non-phenolic 5-5' biphenyl and 5-5' diphenylmethane models were found unreactive.
9. Released fraction of polychlorinated biphenyls from soil-biosolid system using a leaching procedure and its comparison with bioavailable fraction determined by wheat plant uptake.
Science.gov (United States)
Jachero, Lourdes; Leiva, Claudio; Ahumada, Inés; Richter, Pablo
2017-11-01
The bioavailability of polychlorinated biphenyls (PCBs) in soils amended with biosolids was estimated using an aqueous leaching process of the compounds combined with rotating disk sorptive extraction (RDSE), and compared with bioavailability determined through of PCB absorption in wheat plants growing in the same soil-biosolid matrix. The matrices consisted of soil amended with biosolids at doses of 30, 90, and 200 Mg/ha, which increase concomitantly the organic matter content of the matrix. Considering that PCBs were natively absent in both the biosolids and soil used, the compounds were spiked in the biosolids and aged for 10 days. For each biosolid dose, the aqueous leaching profile was studied and equilibrium time was calculated to be 33 h. The leaching fractions determined by RDSE, considering total PCBs studied, were 12, 7, and 6% and the bioavailable fractions absorbed by the wheat root were found to be 0.5, 0.3, and 0.2% for 30, 90, and 200 Mg/ha doses, respectively. Both fractions leachable and bioavailable decrease with both increasing hydrophobicity of the compound (Kow) and increasing in the biosolid dose. It was found that both fractions (leaching and bioavailable) correlated according to the bivariate least squares regression, represented by a coefficient of correlation of 0.86. Therefore, the application of the chemical method involving a leaching procedure is an alternative to estimate the bioavailable fraction of PCBs in wheat plants in a simpler and in a shorter time.
10. Structurally simplified biphenyl combretastatin A4 derivatives retain in vitro anti-cancer activity dependent on mitotic arrest
Science.gov (United States)
Tarade, Daniel; Ma, Dennis; Pignanelli, Christopher; Mansour, Fadi; Simard, Daniel; van den Berg, Sean; Gauld, James; McNulty, James; Pandey, Siyaram
2017-01-01
The cis-stilbene, combretastatin A4 (CA4), is a potent microtubule targeting and vascular damaging agent. Despite promising results at the pre-clinical level and extensive clinical evaluation, CA4 has yet to be approved for therapeutic use. One impediment to the development of CA4 is an inherent conformational instability about the ethylene linker, which joins two aromatic rings. We have previously published preliminary data regarding structurally simplified biphenyl derivatives of CA4, lacking an ethylene linker, which retain anti-proliferative and pro-apoptotic activity, albeit at higher doses. Our current study provides a more comprehensive evaluation regarding the anti-proliferative and pro-apoptotic properties of biphenyl CA4 derivatives in both 2D and 3D cancerous and non-cancerous cell models. Computational analysis has revealed that cytotoxicity of CA4 and biphenyl analogues correlates with predicted tubulin affinity. Additional mechanistic evaluation of the biphenyl derivatives found that their anti-cancer activity is dependent on prolonged mitotic arrest, in a similar manner to CA4. Lastly, we have shown that cancer cells deficient in the extrinsic pathway of apoptosis experience delayed cell death following treatment with CA4 or analogues. Biphenyl derivatives of CA4 represent structurally simplified analogues of CA4, which retain a similar mechanism of action. The biphenyl analogues warrant in vivo examination to evaluate their potential as vascular damaging agents. PMID:28253265
11. Structurally simplified biphenyl combretastatin A4 derivatives retain in vitro anti-cancer activity dependent on mitotic arrest.
Directory of Open Access Journals (Sweden)
Full Text Available The cis-stilbene, combretastatin A4 (CA4, is a potent microtubule targeting and vascular damaging agent. Despite promising results at the pre-clinical level and extensive clinical evaluation, CA4 has yet to be approved for therapeutic use. One impediment to the development of CA4 is an inherent conformational instability about the ethylene linker, which joins two aromatic rings. We have previously published preliminary data regarding structurally simplified biphenyl derivatives of CA4, lacking an ethylene linker, which retain anti-proliferative and pro-apoptotic activity, albeit at higher doses. Our current study provides a more comprehensive evaluation regarding the anti-proliferative and pro-apoptotic properties of biphenyl CA4 derivatives in both 2D and 3D cancerous and non-cancerous cell models. Computational analysis has revealed that cytotoxicity of CA4 and biphenyl analogues correlates with predicted tubulin affinity. Additional mechanistic evaluation of the biphenyl derivatives found that their anti-cancer activity is dependent on prolonged mitotic arrest, in a similar manner to CA4. Lastly, we have shown that cancer cells deficient in the extrinsic pathway of apoptosis experience delayed cell death following treatment with CA4 or analogues. Biphenyl derivatives of CA4 represent structurally simplified analogues of CA4, which retain a similar mechanism of action. The biphenyl analogues warrant in vivo examination to evaluate their potential as vascular damaging agents.
12. Magnesium compounds
Science.gov (United States)
Kramer, D.A.
2007-01-01
Seawater and natural brines accounted for about 52 percent of U.S. magnesium compounds production in 2006. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from sea-water by Premier Chemicals in Florida; from well brines in Michigan by Martin Marietta and Rohm and Haas; and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from brucite by Applied Chemical Magnesias in Texas, from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta and Rohm and Haas from their operations mentioned above. About 59 percent of the magnesium compounds consumed in the United States was used for refractories that are used mainly to line steelmaking furnaces. The remaining 41 percent was consumed in agricultural, chemical, construction, environmental and industrial applications.
13. CLOSURE REPORT FOR CORRECTIVE ACTION UNIT 528: POLYCHLORINATED BIPHENYLS CONTAMINATION NEVADA TEST SITE, NEVADA
Energy Technology Data Exchange (ETDEWEB)
2006-09-01
This Closure Report (CR) describes the closure activities performed at CAU 528, Polychlorinated Biphenyls Contamination, as presented in the Nevada Division of Environmental Protection (NDEP)-approved Corrective Action Plan (CAP) (US. Department of Energy, National Nuclear Security Administration Nevada Site Office [NNSAINSO], 2005). The approved closure alternative was closure in place with administrative controls. This CR provides a summary of the completed closure activities, documentation of waste disposal, and analytical data to confirm that the remediation goals were met.
14. Photoionization and Electron Transfer of Biphenyl within the Channels of Al-ZSM-5 Zeolites.
Science.gov (United States)
Gener, Isabelle; Buntinx, Guy; Brémard, Claude
1999-06-14
Evidence of the photogenerated long-lived biphenyl radical and a trapped electron in the void space of aluminated nonacidic ZSM-5 zeolites has been obtained from the time-resolved UV/Vis absorption, Raman scattering, and EPR spectra. The restoration of the ground states implicates the existence of long-lived positive holes in the framework. © 1999 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.
15. Polychlorinated biphenyls and reproductive hormones in female polar bears at Svalbard.
OpenAIRE
Haave, Marte; Ropstad, Erik; Derocher, Andrew E; Lie, Elisabeth; Dahl, Ellen; Wiig, Øystein; Skaare, Janneche U; Jenssen, Bjørn Munro
2003-01-01
High concentrations of polychlorinated biphenyls (PCBs) in polar bears from Svalbard have increased concern for that population's reproductive health. We examined whether there were associations between the plasma concentrations of PCBs and reproductive hormones [progesterone (P4)] and 17 beta-estradiol (E2)] in free-living female polar bears from Svalbard. Concentrations of P4 depended on reproductive status, and concentrations were lowest in females with offspring--females with cubs and fem...
16. Importance of Passive Diffusion in the Uptake of Polychlorinated Biphenyls by Phagotrophic Protozoa†
OpenAIRE
Kujawinski, Elizabeth B.; Farrington, John W.; Moffett, James W.
2000-01-01
Unicellular protozoan grazers represent a size class of organisms where a transition in the mechanism of chlorobiphenyl (CB) introduction, from diffusion through surface membranes to ingestion of contaminated prey, could occur. This study compares the relative importance of these two processes in the overall uptake of polychlorinated biphenyls by protists. Uptake rates and steady-state concentrations were compared in laboratory cultures of grazing and nongrazing protozoa. These experiments we...
17. Metabolism of chlorobiphenyls by a variant biphenyl dioxygenase exhibiting enhanced activity toward dibenzofuran
International Nuclear Information System (INIS)
Viger, Jean-François; Mohammadi, Mahmood; Barriault, Diane; Sylvestre, Michel
2012-01-01
Highlights: ► Burkholderia xenovorans LB400 biphenyl dioxygenase (BphAE LB400 ) metabolizes PCBs. ► Asn338Gln/Leu409Phe double mutation speeds up electron transfer of enzyme reaction. ► We tested how the mutations affect the PCB-degrading abilities of BphAE LB400 variants. ► The same mutations also broaden the PCB substrate range of BphAE LB400 variants. -- Abstract: The biphenyl dioxygenase of Burkholderia xenovorans LB400 (BphAE LB400 ) catalyzes the dihydroxylation of biphenyl and of several polychlorinated biphenyls (PCBs) but it poorly oxidizes dibenzofuran. In this work we showed that BphAE RR41 , a variant which was previously found to metabolize dibenzofuran more efficiently than its parent BphAE LB400 , metabolized a broader range of PCBs than BphAE LB400 . Hence, BphAE RR41 was able to metabolize 2,6,2′,6′-, 3,4,3′,5′- and 2,4,3′,4′-tetrachlorobiphenyl that BphAE LB400 is unable to metabolize. BphAE RR41 was obtained by changing Thr335Phe336Asn338Ile341Leu409 of BphAE LB400 to Ala335Met336Gln338Val341Phe409. Site-directed mutagenesis was used to create combinations of each substitution, in order to assess their individual contributions. Data show that the same Asn338Glu/Leu409Phe substitution that enhanced the ability to metabolize dibenzofuran resulted in a broadening of the PCB substrates range of the enzyme. The role of these substitutions on regiospecificities toward selected PCBs is also discussed.
18. Metabolism of chlorobiphenyls by a variant biphenyl dioxygenase exhibiting enhanced activity toward dibenzofuran
Energy Technology Data Exchange (ETDEWEB)
Viger, Jean-Francois; Mohammadi, Mahmood; Barriault, Diane [Institut National de la Recherche Scientifique, INRS-Institut Armand-Frappier, Laval, Quebec, Canada H4K 1C2 (Canada); Sylvestre, Michel, E-mail: Michel.Sylvestre@iaf.inrs.ca [Institut National de la Recherche Scientifique, INRS-Institut Armand-Frappier, Laval, Quebec, Canada H4K 1C2 (Canada)
2012-03-09
Highlights: Black-Right-Pointing-Pointer Burkholderia xenovorans LB400 biphenyl dioxygenase (BphAE{sub LB400}) metabolizes PCBs. Black-Right-Pointing-Pointer Asn338Gln/Leu409Phe double mutation speeds up electron transfer of enzyme reaction. Black-Right-Pointing-Pointer We tested how the mutations affect the PCB-degrading abilities of BphAE{sub LB400} variants. Black-Right-Pointing-Pointer The same mutations also broaden the PCB substrate range of BphAE{sub LB400} variants. -- Abstract: The biphenyl dioxygenase of Burkholderia xenovorans LB400 (BphAE{sub LB400}) catalyzes the dihydroxylation of biphenyl and of several polychlorinated biphenyls (PCBs) but it poorly oxidizes dibenzofuran. In this work we showed that BphAE{sub RR41}, a variant which was previously found to metabolize dibenzofuran more efficiently than its parent BphAE{sub LB400}, metabolized a broader range of PCBs than BphAE{sub LB400}. Hence, BphAE{sub RR41} was able to metabolize 2,6,2 Prime ,6 Prime -, 3,4,3 Prime ,5 Prime - and 2,4,3 Prime ,4 Prime -tetrachlorobiphenyl that BphAE{sub LB400} is unable to metabolize. BphAE{sub RR41} was obtained by changing Thr335Phe336Asn338Ile341Leu409 of BphAE{sub LB400} to Ala335Met336Gln338Val341Phe409. Site-directed mutagenesis was used to create combinations of each substitution, in order to assess their individual contributions. Data show that the same Asn338Glu/Leu409Phe substitution that enhanced the ability to metabolize dibenzofuran resulted in a broadening of the PCB substrates range of the enzyme. The role of these substitutions on regiospecificities toward selected PCBs is also discussed.
19. Anaerobic degradation of Polychlorinated Biphenyls (PCBs) and Polychlorinated Biphenyls Ethers (PBDEs), and microbial community dynamics of electronic waste-contaminated soil
Energy Technology Data Exchange (ETDEWEB)
Song, Mengke [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Luo, Chunling, E-mail: clluo@gig.ac.cn [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Li, Fangbai [Guangdong Institute of Eco-environmental and Soil Sciences, Guangzhou 510650 (China); Jiang, Longfei [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); College of Life Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Wang, Yan [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Zhang, Dayi [Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Zhang, Gan [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)
2015-01-01
Environmental contamination caused by electronic waste (e-waste) recycling is attracting increasing attention worldwide because of the threats posed to ecosystems and human safety. In the present study, we investigated the feasibility of in situ bioremediation of e-waste-contaminated soils. We found that, in the presence of lactate as an electron donor, higher halogenated congeners were converted to lower congeners via anaerobic halorespiration using ferrous ions in contaminated soil. The 16S rRNA gene sequences of terminal restriction fragments indicated that the three dominant strains were closely related to known dissimilatory iron-reducing bacteria (DIRB) and those able to perform dehalogenation upon respiration. The functional species performed the activities of ferrous oxidation to ferric ions and further ferrous reduction for dehalogenation. The present study links iron cycling to degradation of halogenated materials in natural e-waste-contaminated soil, and highlights the synergistic roles of soil bacteria and ferrous/ferric ion cycling in the dehalogenation of polychlorinated biphenyls (PCBs) and polybrominated biphenyl ethers (PBDEs). - Highlights: • The biodegradation PCBs and PBDEs in e-waste contaminated soils was studied. • DIRB and arylhalorespiring bacteria were responsive to dehalogenation respiration. • Soil bacteria and Fe ion cycling play synergistic roles in dehalogenation.
20. Compound odontoma
Directory of Open Access Journals (Sweden)
José Marcelo Vargas Pinto
2008-01-01
Full Text Available Odontomas are the most common types of odontogenic tumors, as they are considered more as a developmental anomaly (hamartoma than as a true neoplasia. The aim of the present study is to describe a clinical case of compound odontoma, analyzing its most commonsigns, its region of location, the decade of life and patient’s gender, disorders that may occur as well as the treatment proposed. In order to attain this objective, the method was description of the present clinical case and bibliographic revision, arriving at the result that the treatment for this type of lesion invariably is surgical removal (enucleation and curettage and the prognosis is excellent. The surgical result was followed up in the post-operative period by radiographic exam, and it was possible to conclude that there was complete cicatrization and tissue repair.
1. Magnesium compounds
Science.gov (United States)
Kramer, D.A.
2012-01-01
Seawater and natural brines accounted for about 57 percent of magnesium compounds produced in the United States in 2011. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties LLC from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia LLC in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash Wendover LLC and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma Inc. in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its brine operation in Michigan.
2. Prediction of octanol-air partition coefficients for polychlorinated biphenyls (PCBs) using 3D-QSAR models.
Science.gov (United States)
Chen, Ying; Cai, Xiaoyu; Jiang, Long; Li, Yu
2016-02-01
Based on the experimental data of octanol-air partition coefficients (KOA) for 19 polychlorinated biphenyl (PCB) congeners, two types of QSAR methods, comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA), are used to establish 3D-QSAR models using the structural parameters as independent variables and using logKOA values as the dependent variable with the Sybyl software to predict the KOA values of the remaining 190 PCB congeners. The whole data set (19 compounds) was divided into a training set (15 compounds) for model generation and a test set (4 compounds) for model validation. As a result, the cross-validation correlation coefficient (q(2)) obtained by the CoMFA and CoMSIA models (shuffled 12 times) was in the range of 0.825-0.969 (>0.5), the correlation coefficient (r(2)) obtained was in the range of 0.957-1.000 (>0.9), and the SEP (standard error of prediction) of test set was within the range of 0.070-0.617, indicating that the models were robust and predictive. Randomly selected from a set of models, CoMFA analysis revealed that the corresponding percentages of the variance explained by steric and electrostatic fields were 23.9% and 76.1%, respectively, while CoMSIA analysis by steric, electrostatic and hydrophobic fields were 0.6%, 92.6%, and 6.8%, respectively. The electrostatic field was determined as a primary factor governing the logKOA. The correlation analysis of the relationship between the number of Cl atoms and the average logKOA values of PCBs indicated that logKOA values gradually increased as the number of Cl atoms increased. Simultaneously, related studies on PCB detection in the Arctic and Antarctic areas revealed that higher logKOA values indicate a stronger PCB migration ability. From CoMFA and CoMSIA contour maps, logKOA decreased when substituents possessed electropositive groups at the 2-, 3-, 3'-, 5- and 6- positions, which could reduce the PCB migration ability. These results are
3. A high-throughput screen against pantothenate synthetase (PanC identifies 3-biphenyl-4-cyanopyrrole-2-carboxylic acids as a new class of inhibitor with activity against Mycobacterium tuberculosis.
Directory of Open Access Journals (Sweden)
Full Text Available The enzyme pantothenate synthetase, PanC, is an attractive drug target in Mycobacterium tuberculosis. It is essential for the in vitro growth of M. tuberculosis and for survival of the bacteria in the mouse model of infection. PanC is absent from mammals. We developed an enzyme-based assay to identify inhibitors of PanC, optimized it for high-throughput screening, and tested a large and diverse library of compounds for activity. Two compounds belonging to the same chemical class of 3-biphenyl-4- cyanopyrrole-2-carboxylic acids had activity against the purified recombinant protein, and also inhibited growth of live M. tuberculosis in manner consistent with PanC inhibition. Thus we have identified a new class of PanC inhibitors with whole cell activity that can be further developed.
4. A high-throughput screen against pantothenate synthetase (PanC) identifies 3-biphenyl-4-cyanopyrrole-2-carboxylic acids as a new class of inhibitor with activity against Mycobacterium tuberculosis.
Science.gov (United States)
Kumar, Anuradha; Casey, Allen; Odingo, Joshua; Kesicki, Edward A; Abrahams, Garth; Vieth, Michal; Masquelin, Thierry; Mizrahi, Valerie; Hipskind, Philip A; Sherman, David R; Parish, Tanya
2013-01-01
The enzyme pantothenate synthetase, PanC, is an attractive drug target in Mycobacterium tuberculosis. It is essential for the in vitro growth of M. tuberculosis and for survival of the bacteria in the mouse model of infection. PanC is absent from mammals. We developed an enzyme-based assay to identify inhibitors of PanC, optimized it for high-throughput screening, and tested a large and diverse library of compounds for activity. Two compounds belonging to the same chemical class of 3-biphenyl-4- cyanopyrrole-2-carboxylic acids had activity against the purified recombinant protein, and also inhibited growth of live M. tuberculosis in manner consistent with PanC inhibition. Thus we have identified a new class of PanC inhibitors with whole cell activity that can be further developed.
5. Stir-bar supported micro-solid-phase extraction for the determination of polychlorinated biphenyl congeners in serum samples.
Science.gov (United States)
2016-07-15
In present work, a new configuration of micro-solid phase extraction was introduced and termed as stir-bar supported micro-solid-phase extraction (SB-μ-SPE). A tiny stir-bar was packed inside the porous polypropylene membrane along with sorbent material and the edges of membrane sheet were heat sealed to secure the contents. The packing of stir-bar inside the μ-SPE device does not allow the device to stick with the wall or any corner of the sample vial during extraction, which is, however, a frequent observation in routine μ-SPE. Moreover, it enhances effective surface area of the sorbent exposed to sample solution through continuous agitation (motion and rotation). It also completely immerses the SB-μ-SPE device in the sample solution even for non-polar sorbents. Polychlorinated biphenyls (PCBs) were selected as model compounds and the method performance was evaluated in human serum samples. After extraction, samples were analyzed by gas chromatography mass spectrometry (GC-MS). The factors that affect extraction efficiency of SB-μ-SPE were optimized. Under optimum conditions, a good linearity (0.1-100ngmL(-1)) with coefficients of determinations ranging from 0.9868 to 0.9992 was obtained. Limits of detections were ranged between 0.003 and 0.047ngmL(-1). Acceptable values for inter-day (3.2-9.1%) and intra-day (3.1-7.2%) relative standard deviations were obtained. The optimized method was successfully applied to determine the concentration of PCB congeners in human serum samples. Copyright © 2016 Elsevier B.V. All rights reserved.
6. Impact of size and sorption on degradation of trichloroethylene and polychlorinated biphenyls by nano-scale zerovalent iron
Energy Technology Data Exchange (ETDEWEB)
Petersen, Elijah J. [Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Pinto, Roger A. [Department of Chemical Engineering, University of Michigan, Ann Arbor (United States); Shi, Xiangyang [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620 (China); College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Huang, Qingguo, E-mail: qhuang@uga.edu [Department of Crop and Soil Sciences, University of Georgia, Griffin, GA 30223 (United States)
2012-12-15
Highlights: Black-Right-Pointing-Pointer nZVIs were synthesized using a layer-by-layer or poly(acrylic acid) stabilization approach. Black-Right-Pointing-Pointer These nZVIs were used to degrade TCE and PCB. Black-Right-Pointing-Pointer nZVI coatings impacted reactivity by altering pollutants/particle interactions. Black-Right-Pointing-Pointer Smaller nZVI particle size led to greater reactivity. - Abstract: Nano-scale zerovalent iron (nZVI) has been studied in recent years for environmental remediation applications such as the degradation of chlorinated organic contaminants. To overcome limitations related to the transport of nZVI, it is becoming common to add a polymer stabilizer to limit aggregation and enhance the particle reactivity. Another method investigated to enhance particle reactivity has been to limit particle size through novel synthesis techniques. However, the relative impacts of particle size and interactions of the chemicals with the coatings are not yet well understood. The purpose of this study was to investigate the mechanisms of particle size and polymer coating or polyelectrolyte multilayer (PEM) synthesis conditions on degradation of two common chlorinated contaminants: trichloroethylene (TCE) and polychlorinated biphenyls (PCBs). This was accomplished using two different synthesis techniques, a layer-by-layer approach at different pH values or iron reduction in the presence of varying concentrations of poly(acrylic acid). nZVI produced by both techniques yielded higher degradation rates than a traditional approach. The mechanistic investigation indicated that hydrophobicity and sorption to the multilayer impacts the availability of the hydrophobic compound to the nZVI and that particle size also had a large role with smaller particles having stronger dechlorination rates.
7. Individual Polychlorinated Biphenyl (PCB) Congeners Produce Tissue- and Gene-Specific Effects on Thyroid Hormone Signaling during Development
Science.gov (United States)
Giera, Stefanie; Bansal, Ruby; Ortiz-Toro, Theresa M.; Taub, Daniel G.
2011-01-01
Polychlorinated biphenyls (PCB) are industrial chemicals linked to developmental deficits that may be caused in part by disrupting thyroid hormone (TH) action by either reducing serum TH or interacting directly with the TH receptor (TR). Individual PCB congeners can activate the TR in vitro when the metabolic enzyme cytochrome P4501A1 (CYP1A1) is induced, suggesting that specific PCB metabolites act as TR agonists. To test this hypothesis in vivo, we compared two combinations of PCB congeners that either activate the TR (PCB 105 and 118) or not (PCB 138 and 153) in the presence or absence of a PCB congener (PCB 126) that induces CYP1A1 in vitro. Aroclor 1254 was used as a positive control, and a group treated with propylthiouracil was included to characterize the effects of low serum TH. We monitored the effects on TH signaling in several peripheral tissues by measuring the mRNA expression of well-known TH-response genes in these tissues. Aroclor 1254 and its component PCB 105/118/126 reduced total T4 to the same extent as that of propylthiouracil but increased the expression of some TH target genes in liver. This effect was strongly correlated with CYP1A1 expression supporting the hypothesis that metabolism is necessary. Effects were gene and tissue specific, indicating that tissue-specific metabolism is an important component of PCB disruption of TH action and that PCB metabolites interact in complex ways with the TR. These are essential mechanisms to consider when evaluating the health risks of contaminant exposures, for both PCB and other polycyclic compounds known to interact with nuclear hormone receptors. PMID:21540284
8. Polybrominated diphenyl ethers, polychlorinated dibenzo-dioxins, -furans, and -biphenyls in three species of Antarctic penguins.
Science.gov (United States)
Corsolini, Simonetta; Borghesi, Nicoletta; Schiamone, Alessandra; Focardi, Silvano
2007-09-01
Fish-eating seabirds are recognized to be at risk of accumulating toxic contaminants due to their high position in the trophic web and to their low ability to metabolize xenobiotic compounds. Penguins are widely distributed in Antarctica and represent an important fraction of the Antarctic biomass. They feed mainly on krill and, depending on krill availability, also on fish. It has been reported that predators may be a sink for volatile and toxic chemicals and this may pose a serious environmental problem. Polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-dioxins (PCDDs), -furans (PCDFs), and -biphenyls (PCBs), including non-ortho congeners, hexachlorobenzene (HCB) and p,p'-DDE, were quantified in three species of Antarctic Pygoscelids in order to evaluate their accumulation patterns. The potential toxicity of twenty-two dioxin-like congeners was assessed and expressed as 2,3,7,8-tetraCDD equivalents (TEQs). Differences between males and females were investigated. Blood samples of the Adélie penguin Pygoscelis adeliae, Chinstrap penguin Pygoscelis antarctica and Gentoo penguin Pygoscelis papua were collected at Admiralty Bay, King George Is (62 degrees 10'39" S, 58 degrees 26'46" W) in February 2004. Halogenated hydrocarbons were identified and quantified using gas chromatography coupled with gas chromatography mass spectrometry analyses. Results are expressed on a wet weight basis. HCB, p,p'-DDE and sigmaPCBs were higher in Adélie penguins (6.7 +/- 6.1, 8.2 +/- 3.3 and 9.8 +/- 3.8 ng/g, respectively) than in Chinstrap and Gentoo penguins, both of which showed values in the same order of magnitude, but approximately 40% lower than Adélie penguins. Hexa-CBs ranged 35-45% of the residue. Low-chlorinated PCBs (nos. 70+76+95+ 56+60+101) accounted for 40-60% in the three species. PCB101 made up 15% of the residue in Adélie penguins. PBDEs were 291 +/- 477, 107 +/- 104 and 116 +/- 108 pg/g in Adélie, Chinstrap and Gentoo penguins, respectively; the
9. Octanol-air partition coefficients of polybrominated biphenyls.
Science.gov (United States)
Hongxia, Zhao; Jingwen, Chen; Xie, Quan; Baocheng, Qu; Xinmiao, Liang
2009-03-01
The octanol-air partition coefficients (K(OA)) for PBB15, PBB26, PBB31, PBB49, PBB103 and PBB153 were determined as a function of temperature using a gas chromatographic retention time technique with 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (p,p'-DDT) as a reference substance. The internal energies of phase change from octanol to air (Delta(OA)U) were calculated for the six compounds and were in the range from 74 to 116 kJ mol(-1). Simple regression equations of log K(OA) versus relative retention times (RRTs) on gas chromatography (GC), and log K(OA) versus molecular connectivity indexes (MCI) were obtained, for which the correlation coefficients (r(2)) were greater than 0.985 at 283.15K and 298.15K. Thus the K(OA) values of the remaining PBBs can be predicted by using their RRTs and MCI according to these relationships.
10. K Basin sludge polychlorinated biphenyl removal technology assessment
International Nuclear Information System (INIS)
Ashworth, S.C.
1998-01-01
The two Hanford K Basins are water-filled concrete pools that contain over 2,100 metric tons of N Reactor fuel elements stored in aluminum or stainless steel canisters. During the time the fuel has been stored, approximately 50 m3 of heterogeneous solid material have accumulated in the basins. This material, referred to as sludge, is a mixture of fuel corrosion products, metallic bits of spent fuel and zirconium clad iron and metal corrosion products and silica from migrating sands. Some of the sludges also contain PCBs. The congener group of PCBs was identified as Aroclor 1254. The maximum concentration of sludge PCBS was found to be 140 ppm (as settled wet basis). However, the distribution of the PCBs is non-uniform throughout the sludge (i.e., there are regions of high and low concentrations and places where no PCBs are present). Higher concentrations could be present at various locations. Aroclors 1016/1242, 1221, 1248, 1254, and 1260 were identified and quantified in K West (KW) Canister sludge. In some of these samples, the concentration of 1260 was higher than 1254. The sludge requires pre-treatment to meet tank farm waste acceptance criteria, Among the numerous requirements, the sludge should be retreated so that it does not contain regulated levels of Toxic Substances Control Act (TSCA) compounds. Because of their stable chemistry and relative insolubility in water, PCBs are difficult to treat. They also resist degradation from heat and electrical charges. This stability has resulted in environmental persistence which has prompted the development of a variety of new cleanup processes including supercritical processes, advanced oxidation, dehalogenation and others. Hopefully, most of the new processes are discussed herein. Information on new processes are being received and will be evaluated in a future revision
11. Health risk assessment for polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans, and polychlorinated naphthalenes in seafood from Guangzhou and Zhoushan, China
International Nuclear Information System (INIS)
Jiang Qinting; Hanari, Nobuyasu; Miyake, Yuichi; Okazawa, Tsuyoshi; Lau, Ridge K.F.; Chen Kun; Wyrzykowska, Barbara; So, M.K.; Yamashita, Nobuyoshi; Lam, Paul K.S.
2007-01-01
This study determined the concentrations of organochlorine contaminants in common seafood in two Chinese coastal cities (Guangzhou and Zhoushan), and assessed the health risk due to the daily consumption of contaminated seafood. Twenty-six pooled samples, belonging to five food categories (fish, bivalves, shrimp, crab, and cephalopods), were purchased from local markets in Guangzhou and Zhoushan in 2003 and 2004. These samples were analyzed for total polychlorinated biphenyls (PCBs), non- and mono-ortho-PCBs (coplanar PCBs), polychlorinated naphthalenes (PCNs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/DFs). The concentrations of total PCBs and coplanar PCBs in fish samples were higher in Guangzhou than in Zhoushan, while the levels of PCNs and PCDDs/DFs were comparable between the two cities. The total daily intake values of dioxin-like compounds were 1.05 and 0.86 pg WHO-TEQ/kg body weight in Guangzhou and Zhoushan, respectively. Hazard ratios of non-cancer risk in the two cities were all less than unity. - Health risk assessment of organochlorine compounds associated with seafood consumption reveals low health risks for two coastal populations in China
12. Determination of Chlorinated Pesticides and Polychlorinated Biphenyls in Edible Oils and Fats using MSPD Extraction and Freeze Lipids-Filtration Cleanup with GC-ECD Measurement
International Nuclear Information System (INIS)
Pla Jauregui, Daniela; Valcarcel Rojas, Lino; Estevez Alvarez, Juan
2015-01-01
Persistent organic pollutants (POPs) such as organo chlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) have numerous adverse effects on human health. Although their use have been banned or restricted, residues of these compounds can be found in foods, especially those with high fat content. The purpose of this study was to establish a rapid and simple analytical method for the determination of these compounds in edible oils and fats. Matrix solid-phase dispersion (MSPD) was used for the simultaneous extraction and purification of analytes from samples using an acetonitrile - acetone (19:1, v/v) mixture as eluting solvent. Lipids remaining in the extract were removed by freezing-lipid filtration, prior to analytes re-extraction with n-hexane. The measurement was performed using a gas chromatograph with electron capture detector (GC-ECD). Spiking experiments were carried out to determine the recovery, precision and limits of detection (LODs) of the method. Recoveries were higher than 70% and detection limits were in the range of 20 ng/g to 90 ng/g. These LOD values are lower than the maximum permissible limit which makes this method useful for the purpose intended. This method was successfully applied to the analysis of vegetable oils and butters sampled from the market. (Author)
13. Optimizing Polychlorinated Biphenyl Degradation by Flavonoid-Induced Cells of the Rhizobacterium Rhodococcus erythropolis U23A.
Directory of Open Access Journals (Sweden)
Thi Thanh My Pham
Full Text Available There is evidence that many plant secondary metabolites may act as signal molecules to trigger the bacterial ability to metabolize polychlorinated biphenyls (PCBs during the rhizoremediation process. However, the bases for the PCB rhizoremediation process are still largely unknown. The rhizobacterium Rhodococcus erythropolis U23A is unable to use flavanone as a growth substrate. However, on the basis of an assay that monitors the amount of 4-chlorobenzoate produced from 4-chlorobiphenyl by cells grown co-metabolically on flavanone plus sodium acetate, this flavonoid was previously found to be a potential inducer of the U23A biphenyl catabolic pathway. In this work, and using the same assay, we identified ten other flavonoids that did not support growth, but that acted as inducers of the U23A biphenyl pathway, and we confirmed flavonoid induction of the biphenyl catabolic pathway using quantitative real-time polymerase chain reaction (RT-qPCR on the bphA gene. We also examined the effect of the growth co-substrate on flavonoid induction. Sodium acetate was replaced by glucose, mannose, sucrose, or mannitol, which are sugars found in plant root exudates. The data showed that the level of induction of strain U23A biphenyl-degrading enzymes was significantly influenced by the nature and concentration of the flavonoid in the growth medium, as well as by the substrate used for growth. Sucrose allowed for an optimal induction response for most flavonoids. Some flavonoids, such as flavone and isoflavone, were better inducers of the biphenyl catabolic enzymes than biphenyl itself. We also found that all flavonoids tested in this work were metabolized by strain U23A during co-metabolic growth, but that the metabolite profiles, as well as the level of efficiency of degradation, differed for each flavonoid. To obtain insight into how flavonoids interact with strain U23A to promote polychlorinated biphenyl (PCB degradation, we determined the concentration of
14. Toxicological study of a polyphenyl-type chemical compound used by the thermal transfer department; Etude toxicologique d'un produit chimique du type polyphenyle utilise par la section des transferts thermiques
Energy Technology Data Exchange (ETDEWEB)
Rinaldi, R.; Alix, D.
1961-07-01
This note reports an experimentation of toxicological tests performed on two mice breed by different ways (skin absorption, respiratory route, digestive tract) in order to assess the toxicology of a chemical compound containing a bi-phenyl eutectic and bi-phenyl oxide. The authors describe effects noticed among mice depending on the absorption way. They notice the caustic action of the product, but that an accidental absorption through the digestive tract would not result in an acute and severe intoxication. As far as chronic intoxication is concerned, daily inhalations do not seem to have any haematological impact on mice.
15. Isotopically modified compounds
International Nuclear Information System (INIS)
Kuruc, J.
2009-01-01
In this chapter the nomenclature of isotopically modified compounds in Slovak language is described. This chapter consists of following parts: (1) Isotopically substituted compounds; (2) Specifically isotopically labelled compounds; (3) Selectively isotopically labelled compounds; (4) Non-selectively isotopically labelled compounds; (5) Isotopically deficient compounds.
16. Use of feathers to assess polychlorinated biphenyl and organochlorine pesticide exposure in top predatory bird species of Pakistan
International Nuclear Information System (INIS)
Abbasi, Naeem Akhtar; Eulaers, Igor; Jaspers, Veerle L.B.; Chaudhry, Muhammad Jamshed Iqbal; Frantz, Adrien; Ambus, Per Lennart; Covaci, Adrian; Malik, Riffat Naseem
2016-01-01
Little is known about the levels of organochlorines (OCs) in predatory bird species from Asia or the factors governing their concentrations. This study is the first report on concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in predatory birds of Pakistan. The concentrations of PCBs and OCPs were investigated using tail feathers of ten different species of predatory birds. In addition, concentration differences among body, tail, primary and secondary feathers were investigated for six individuals of black kite (Milvus migrans). Ranges of concentrations were highest for dichlorodiphenyldichloroethylene (p,p′-DDE: 0.11–2163 ng g − 1 dry wt.) followed by dichlorodiphenyltrichloroethane (p,p′-DDT: 0.36–345 ng g − 1 dry wt.), hexachlorobenzene (HCB: 0.02–34 ng g − 1 dry wt.), ∑ PCBs (0.03–16 ng g − 1 dry wt.) and trans-nonachlor (TN; 0.01–0.13 ng g − 1 dry wt.). CB 118, 153, 138, and 180 along with p,p′-DDE were found as the most prevalent compounds. ∑ PCBs and ∑ DDTs were significantly different among species (both p < 0.01) and omnivorous, scavengers, carnivorous and piscivorous trophic guilds (all p < 0.03). Only ∑ PCBs were significantly differentamong different families of birds (p < 0.01). Values of stable isotopes (δ 13 C and δ 15 N) differed significantly (all p < 0.01) among species, families, trophic guilds as well as terrestrial and aquatic habitat but not between nocturnal and diurnal predators (p = 0.22 for δ 13 C; p = 0.50 for δ 15 N). Concentrations of ∑ PCBs, ∑ DDTs and trans-nonachlor, but not HCB (p = 0.86), were significantly different among different feather types (all p < 0.01). Trophic and taxonomic affiliation as well as dietary carbon sources (δ 13 C) for species were identified as the variables best explaining the observed variation in exposure to the studied compounds. The significance of contributing factors responsible for OC contamination differences in
17. Use of feathers to assess polychlorinated biphenyl and organochlorine pesticide exposure in top predatory bird species of Pakistan
Energy Technology Data Exchange (ETDEWEB)
Abbasi, Naeem Akhtar [Environmental Biology and Ecotoxicology Laboratory, Department of Environmental Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Eulaers, Igor [Department of Bioscience, Aarhus University, Frederiksborgvej 399, P.O. Box 358, 4000 Roskilde (Denmark); Jaspers, Veerle L.B., E-mail: veerle.jaspers@ntnu.no [Environmental Toxicology, Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim (Norway); Chaudhry, Muhammad Jamshed Iqbal [Environmental Biology and Ecotoxicology Laboratory, Department of Environmental Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320 (Pakistan); WWF-Pakistan, Ferozpur Road, PO Box 5180, Lahore 54600 (Pakistan); Frantz, Adrien [Sorbonne Universités, UPMC Univ Paris 06, UPEC, Paris 7, CNRS, INRA, IRD, Institut d' Ecologie et des Sciences de l' Environnement de Paris, F-75005 Paris (France); Ambus, Per Lennart [Center for Permafrost, Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 København K (Denmark); Covaci, Adrian [Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Malik, Riffat Naseem, E-mail: r_n_malik2000@yahoo.co.uk [Environmental Biology and Ecotoxicology Laboratory, Department of Environmental Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320 (Pakistan)
2016-11-01
Little is known about the levels of organochlorines (OCs) in predatory bird species from Asia or the factors governing their concentrations. This study is the first report on concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in predatory birds of Pakistan. The concentrations of PCBs and OCPs were investigated using tail feathers of ten different species of predatory birds. In addition, concentration differences among body, tail, primary and secondary feathers were investigated for six individuals of black kite (Milvus migrans). Ranges of concentrations were highest for dichlorodiphenyldichloroethylene (p,p′-DDE: 0.11–2163 ng g{sup −} {sup 1} dry wt.) followed by dichlorodiphenyltrichloroethane (p,p′-DDT: 0.36–345 ng g{sup −} {sup 1} dry wt.), hexachlorobenzene (HCB: 0.02–34 ng g{sup −} {sup 1} dry wt.), ∑ PCBs (0.03–16 ng g{sup −} {sup 1} dry wt.) and trans-nonachlor (TN; 0.01–0.13 ng g{sup −} {sup 1} dry wt.). CB 118, 153, 138, and 180 along with p,p′-DDE were found as the most prevalent compounds. ∑ PCBs and ∑ DDTs were significantly different among species (both p < 0.01) and omnivorous, scavengers, carnivorous and piscivorous trophic guilds (all p < 0.03). Only ∑ PCBs were significantly differentamong different families of birds (p < 0.01). Values of stable isotopes (δ{sup 13}C and δ{sup 15}N) differed significantly (all p < 0.01) among species, families, trophic guilds as well as terrestrial and aquatic habitat but not between nocturnal and diurnal predators (p = 0.22 for δ{sup 13}C; p = 0.50 for δ{sup 15}N). Concentrations of ∑ PCBs, ∑ DDTs and trans-nonachlor, but not HCB (p = 0.86), were significantly different among different feather types (all p < 0.01). Trophic and taxonomic affiliation as well as dietary carbon sources (δ{sup 13}C) for species were identified as the variables best explaining the observed variation in exposure to the studied compounds. The significance of
18. Transient spectral hole burning observed on the single-molecule level in terrylene-doped biphenyl
International Nuclear Information System (INIS)
Pärs, M.; Palm, V.; Kikas, J.
2014-01-01
We use the method of fluorescence correlation spectroscopy to analyze the single-molecule (SM) spectroscopy data earlier recorded for a special type of terrylene SM impurity center (referred as “spectrally confined unstable molecule”, SCM) in an incommensurate single crystal of biphenyl. The SCM's SM line seems to be chaotically jumping around within a broad “spectral envelope” and was first considered being subject to a peculiar spectral diffusion behavior. However, our correlation analysis reveals that all the features observed for SCM at 1.8 K are consistent with an assumption that this SM center participates in a process of reversible (transient) spectral hole burning (THB) earlier observed for terrylene-doped polycrystalline biphenyl. No observations of THB processes on SM level have been so far reported for this impurity system, partially due to a low concentration of relevant impurity centers. Another reason making searching for such centers experimentally challenging is an unusual SM line behavior: the photoinduced transition to a metastable “dark state” leads to the SM line saturational broadening, which is much stronger than the triplet broadening. Hence required prolonged observation is often prevented by an SM act of persistent spectral hole burning. - Highlights: • SCM—special type of terrylene single-molecule center in incommensurate biphenyl. • An unusually stable SCM was investigated during several hours at T=1.8 K. • SCM undergoes photoinduced transitions to an unknown metastable “dark state” (DS). • The long DS lifetime causes strong saturational broadening of SCM spectral line. • SCM participates in an earlier observed process of transient hole burning
19. Secondary sex ratio in relation to exposures to polychlorinated biphenyls, dichlorodiphenyl dichloroethylene and methylmercury
DEFF Research Database (Denmark)
Timmermann, Clara Amalie Gade; Choi, Anna L; Petersen, Maria Skaalum
2017-01-01
This study was undertaken to assess the potential impact of maternal exposures to polychlorinated biphenyl (PCB), dichlorodiphenyl dichloroethylene (DDE) and methylmercury on the secondary sex ratios (the ratio of male to female live births) over a span of 23 years. The study includes prospective......% CI = 2-17%), respectively, of giving birth to a boy. In conclusion, maternal exposure to ΣPCB, DDE and methylmercury was associated with a slightly increased secondary sex ratio. The impact of paternal exposures could not be taken into account and deserves attention....
20. Degradation of polychlorinated biphenyls in the rhizosphere of rape, Brassica napus L.
Science.gov (United States)
Javorská, Hana; Tlustos, Pavel; Kaliszová, Regina
2009-06-01
The objective of this study was to investigate the rhizosphere effect of rape plants on polychlorinated biphenyls (PCB) dissipation in soils spiked with seven indicator congeners. Depletion of PCB in the rhizosphere was significantly higher in the soil with lower organic matter content. While in the Chernozem soil, 87% of PCB related to bulk soil were found in the 1st mm from roots, only 62%-69% were found in the Fluvisol soil with no significant influence of increased initial PCB concentration. Further from the roots, the concentration of lower chlorinated congeners decreased, which indicates their greater biodegradation in comparison with more chlorinated ones.
1. Polychlorinated biphenyls (PCBs) in the frame of the dismantling of nuclear facilities
International Nuclear Information System (INIS)
Hagenbart, Lars; Held, Christian; Reichert, Alexander
2013-01-01
During construction and maintenance of nuclear facilities PCB (polychlorinated biphenyls) containing paints were used in a large extent in the past. The WAK dismantling and disposal Company has dismantles such facilities and identified the PCB in the buildings. Besides the radionuclides the conventional hazardous material group of the PCBs has also to be disposed. The respective legal regulations have to be considered. In the frame of the contribution the radiological release of building structures with respect to re-use or demolition and residual PCB containing materials is discussed. The radiological disposal in final repositories and the conventional disposal regulations for releasable residual wastes are reported.
2. Whole-Cell Fluorescent Biosensors for Bioavailability and Biodegradation of Polychlorinated Biphenyls
Directory of Open Access Journals (Sweden)
David Ryan
2010-02-01
Full Text Available Whole-cell microbial biosensors are one of the newest molecular tools used in environmental monitoring. Such biosensors are constructed through fusing a reporter gene such as lux, gfp or lacZ,to a responsive promoter. There have been many reports of the applications of biosensors, particularly their use in assaying pollutant toxicity and bioavailability. This paper reviews the basic concepts behind the construction of whole-cell microbial biosensors for pollutant monitoring, and describes the applications of two such biosensors for detecting the bioavailability and biodegradation of Polychlorinated Biphenyls (PCBs.
3. Electrodialytic remediation of polychlorinated biphenyls contaminated soil with iron nanoparticles and two different surfactants
DEFF Research Database (Denmark)
Gomes, Helena I.; Dias-Ferreira, Celia; Ottosen, Lisbeth M.
2014-01-01
Polychlorinated biphenyls (PCB) are persistent organic pollutants (POP) that strongly adsorb in soils and sediments. There is a need to develop new and cost-effective solutions for the remediation of PCB contaminated soils. The suspended electrodialytic remediation combined with zero valent iron......ZVI showed encouraging tendencies and a base is thus formed for further optimization towards a new method for remediation of PCB polluted soils....... nanoparticles (nZVI) could be a competitive alternative to the commonly adapted solutions of incineration or landfilling. Surfactants can enhance the PCB desorption, dechlorination, and the contaminated soil cleanup. In this work, two different surfactants (saponin and Tween 80) were tested to enhance PCB...
4. Levels of polychlorinated biphenyls and pesticides in bluefish before and after cooking.
Science.gov (United States)
Trotter, W J; Corneliussen, P E; Laski, R R; Vannelli, J J
1989-01-01
Similar levels of polychlorinated biphenyls (PCBs), pesticides, and fat were found in 20 correlated uncooked and cooked (baked) bluefish fillets. Fillets averaged 2.5 ppm PCBs as Aroclor 1254 (whole basis) before cooking; after cooking, with the oil drippings and skin discarded, the average PCB level was 2.7 ppm. Although PCBs, lipophilic pesticides, and fat were lost along with oil drippings and skin that were discarded after cooking, the moisture loss in the fillets during cooking compensated for these weight losses almost completely. After the fillets were cooked and the oil drippings and skin were discarded, the PCB content of the fillets was 27% lower on the average.
5. Transcriptional Response of Rhodococcus aetherivorans I24 to Polychlorinated Biphenyl-Contaminated Sediments
KAUST Repository
Puglisi, Edoardo
2010-04-06
We used a microarray targeting 3,524 genes to assess the transcriptional response of the actinomycete Rhodococcus aetherivorans I24 in minimal medium supplemented with various substrates (e. g., PCBs) and in both PCB-contaminated and non-contaminated sediment slurries. Relative to the reference condition (minimal medium supplemented with glucose), 408 genes were upregulated in the various treatments. In medium and in sediment, PCBs elicited the upregulation of a common set of 100 genes, including gene-encoding chaperones (groEL), a superoxide dismutase (sodA), alkyl hydroperoxide reductase protein C (ahpC), and a catalase/peroxidase (katG). Analysis of the R. aetherivorans I24 genome sequence identified orthologs of many of the genes in the canonical biphenyl pathway, but very few of these genes were upregulated in response to PCBs or biphenyl. This study is one of the first to use microarrays to assess the transcriptional response of a soil bacterium to a pollutant under conditions that more closely resemble the natural environment. Our results indicate that the transcriptional response of R. aetherivorans I24 to PCBs, in both medium and sediment, is primarily directed towards reducing oxidative stress, rather than catabolism. © 2010 Springer Science+Business Media, LLC.
6. Atmospheric polychlorinated biphenyls in Indian cities: Levels, emission sources and toxicity equivalents
International Nuclear Information System (INIS)
Chakraborty, Paromita; Zhang, Gan; Eckhardt, Sabine; Li, Jun; Breivik, Knut; Lam, Paul K.S.; Tanabe, Shinsuke; Jones, Kevin C.
2013-01-01
Atmospheric concentration of Polychlorinated biphenyls (PCBs) were measured on diurnal basis by active air sampling during Dec 2006 to Feb 2007 in seven major cities from the northern (New Delhi and Agra), eastern (Kolkata), western (Mumbai and Goa) and southern (Chennai and Bangalore) parts of India. Average concentration of Σ 25 PCBs in the Indian atmosphere was 4460 (±2200) pg/m −3 with a dominance of congeners with 4–7 chlorine atoms. Model results (HYSPLIT, FLEXPART) indicate that the source areas are likely confined to local or regional proximity. Results from the FLEXPART model show that existing emission inventories cannot explain the high concentrations observed for PCB-28. Electronic waste, ship breaking activities and dumped solid waste are attributed as the possible sources of PCBs in India. Σ 25 PCB concentrations for each city showed significant linear correlation with Toxicity equivalence (TEQ) and Neurotoxic equivalence (NEQ) values. Highlights: •Unlike decreasing trend of PCBs in United States and European countries, high levels of PCBs remain in the Indian atmosphere. •Existing emission inventories cannot explain the high PCB concentrations in Indian atmosphere. •Electronic waste recycling, ship dismantling and open burning of municipal solid waste are implicated as potential sources. -- Measurement of atmospheric Polychlorinated biphenyls in seven major Indian cities
7. Net trophic transfer efficiencies of polychlorinated biphenyl congeners to lake trout (Salvelinus namaycush) from its prey
Science.gov (United States)
Madenjian, Charles P.; David, Solomon R.; Rediske, Richard R.; O’Keefe, James P.
2012-01-01
Lake trout (Salvelinus namaycush) were fed bloater (Coregonus hoyi) in eight laboratory tanks over a 135-d experiment. At the start of the experiment, four to nine fish in each tank were sacrificed, and the concentrations of 75 polychlorinated biphenyl (PCB) congeners within these fish were determined. Polychlorinated biphenyl congener concentrations were also determined in the 10 lake trout remaining in each of the eight tanks at the end of the experiment as well as in the bloater fed to the lake trout. Each lake trout was weighed at the start and the end of the experiment, and the amount of food eaten by the lake trout was recorded. Using these measurements, net trophic transfer efficiency (γ) from the bloater to the lake trout in each of the eight tanks was calculated for each of the 75 congeners. Results showed that γ did not vary significantly with the degree of chlorination of the PCB congeners, and γ averaged 0.66 across all congeners. However,γ did show a slight, but significant, decrease as logKOW increased from 6.0 to 8.2. Activity level of the lake trout did not have a significant effect on γ.
8. Polychlorinated biphenyls and reproductive hormones in female polar bears at Svalbard.
Science.gov (United States)
Haave, Marte; Ropstad, Erik; Derocher, Andrew E; Lie, Elisabeth; Dahl, Ellen; Wiig, Øystein; Skaare, Janneche U; Jenssen, Bjørn Munro
2003-04-01
High concentrations of polychlorinated biphenyls (PCBs) in polar bears from Svalbard have increased concern for that population's reproductive health. We examined whether there were associations between the plasma concentrations of PCBs and reproductive hormones [progesterone (P4)] and 17 beta-estradiol (E2)] in free-living female polar bears from Svalbard. Concentrations of P4 depended on reproductive status, and concentrations were lowest in females with offspring--females with cubs and females with yearlings. In these females, the P4 concentrations were positively correlated with plasma sigma PCBs (sum of all analyzed polychlorinated biphenyl congeners) concentrations. The sigma PCBs concentrations explained 27% of the variation in the P4 concentrations. There were no correlations between sigma PCBs and E2 and cortisol in any of the groups of polar bears, or between sigma PCBs and P4 in single polar bears. Although the sigma PCBs-P4 relationship in female polar bears with offspring is not evidence per se of a direct cause-effect association, the results indicate that PCBs may affect levels of P4 in polar bear females. There is a clear need to further assess the hormone balance and population health of polar bears at Svalbard.
9. Polychlorinated biphenyls in surface soil in urban and background areas of Mongolia
International Nuclear Information System (INIS)
Mamontova, Elena A.; Mamontov, Alexander A.; Tarasova, Eugenia N.; Kuzmin, Mikhail I.; Ganchimeg, Darmaa; Khomutova, Marina Yu.; Gombosuren, Odontuya; Ganjuurjav, Erdenebayasgalan
2013-01-01
Polychlorinated biphenyls (PCBs) were measured in soil in some industrial towns (Ulaanbaatar, Suhbaatar, Erdenet, Darhan, Tsetserleg, Hovd, Ulaangom, Altay, Bayanhongor, Arvayheer, Saynshand, Choybalsan) and in background and rural areas of Mongolia. The average sum of all investigated PCB congeners in soil of Mongolia comes to 7.4 ng/g dry weight (DW) and varies from 0.53 ng/g DW till 114 ng/g DW. PCB levels in soil from towns are significantly higher than those in soil from background and rural areas. The PCB homological composition in soil sampled in highly-PCB-polluted sites is similar to the PCB homological pattern in Sovol and Aroclor 1254. Significant correlation between soil organic carbon and low chlorinated PCB both for towns and background sites was found. Significant differences in PCB means in soil in different natural zones were found. -- Highlights: •First study to measure PCBs in surface soil sampled throughout Mongolia. •The PCB patterns in polluted soil were similar to those in Sovol or Aroclor 1254. •Significant differences in PCB means in soil in different natural zones were found. -- Polychlorinated biphenyls were measured in soils throughout Mongolia
10. Azo biphenyl polyurethane: Preparation, characterization and application for optical waveguide switch
Science.gov (United States)
Jiang, Yan; Da, Zulin; Qiu, Fengxian; Yang, Dongya; Guan, Yijun; Cao, Guorong
2018-01-01
Azo waveguide polymers are of particular interest in the design of materials for applications in optical switch. The aim of this contribution was the synthesis and thermo-optic waveguide switch properties of azo biphenyl polyurethanes. A series of monomers and azo biphenyl polyurethanes (Azo BPU1 and Azo BPU2) were synthesized and characterized by FT-IR, UV-Vis spectroscopy and 1H NMR. The physical and mechanical properties of thin polymer films were measured. The refractive index and thermo-optic coefficient (dn/dT) of polymer films were investigated for TE (transversal electric) polarizations by ATR technique. The transmission loss of film was measured using the Charge Coupled Device digital imaging devices. The results showed the Azo BPU2 containing chiral azobenzene chromophore had higher dn/dT and lower transmission loss. Subsequently, a 1 × 2 Y-branch and 2 × 2 Mach-Zehnder optical switches based on the prepared polymers were designed and simulated. The results showed that the power consumption of all switches was less than 1.0 mW. Compared with 1 × 2 Y-branch optical switch, the 2 × 2 Mach-Zehnder optical switches based on the same polymer have the faster response time, which were about only 1.2 and 2.0 ms, respectively.
11. Global pollution monitoring of polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs) and coplanar polychlorinated biphenyls (coplanar PCBs) using skipjack tuna as bioindicator
Energy Technology Data Exchange (ETDEWEB)
Ueno, D.; Watanabe, M.; Subraminian, A.N.; Tanabe, S. [Ehime Univ. (Japan); Tanaka, H. [National Research Inst. of Fisheries and Environment of Inland Sea (Japan); Fillmann, G. [Fundacao Univ. Federal do Rio Grande (Brazil); Lam, P.K.S.; Zheng, G.J. [City Univ. of Hong Kong (Hong Kong); Muchtar, M.; Razak, H. [Indonesian Inst. of Sciences (Indonesia); Prudente, M. [De La Salle Univ. (Philippines); Chung, K. [Sungkyunkwan Univ. (Korea)
2004-09-15
Worldwide contamination by dioxins and related compounds, such as polychlorinated dibenzop- dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (coplanar PCBs) representing persistent organic pollutants (POPs) have been of great concern due to their persistency in the environment, highly bioaccumulative nature and adverse effects on wildlife and humans. Several studies on air samples and marine organisms from open seas suggested a long range transport of these compounds through atomosphere. Although several investigators have monitored dioxins pollution in localized areas, information on the global distribution of dioxins which can explain their atomospheric transport, behavior and fate are still limited. Skipjack tuna is primarily distributed from offshore waters to open seas in tropical and temperate regions almost all over the world such as the Pacific, Atlantic and Indian Oceans6. This species is an important commercial fish and its ecology and biology has been well studied. Moreover, suitability of skipjack tuna for global monitoring of organic pollutants (DDTs, HCHs PBDEs, organotins, etc.) has been established in our previous report, indicating that migration pattern, growth stage and sex of these animals have no or little effect on the variations of POPs residue levels in their bodies. Hence this species reflected POPs pollution levels in seawater when and where they were collected, caused by the rapid equilibrium partitioning between seawater and body lipid. These facts made skipjack tuna a suitable bioindicator for monitoring the contamination status of dioxins and related compounds. The objectives of this study are to elucidate the global distribution of dioxins (PCDD/Fs and coplanar PCBs) in offshore waters and open seas, and to understand the transport and behaviour of these chemicals using skipjack tuna as bioindicator.
12. Rubber compounding and processing
CSIR Research Space (South Africa)
John, MJ
2014-06-01
Full Text Available This chapter presents an overview on the compounding and processing techniques of natural rubber compounds. The introductory portion deals with different types of rubbers and principles of rubber compounding. The primary and secondary fillers used...
13. Determination of levels of polychlorinated biphenyls (PCBs) present in caulk and window glazing material samples from older buildings
Science.gov (United States)
Levels of polychlorinated biphenyls (PCBs) in caulk and window glazing material samples from older buildings were determined, using a method developed for this purpose. This method was evaluated by analyzing a combination of 47 samples of caulk, glazing materials, including quali...
14. Mixed function oxidase dependent biotransformation of polychlorinated biphenyls by different species of fish from the North Sea
DEFF Research Database (Denmark)
Mehrtens, G.; Laturnus, F.
1999-01-01
Mixed function oxidase (MFO) dependent biotransformation of polychlorinated biphenyls (PCBs) was measured in three different fish species from the North Sea. Liver microsomes of plaice (Pleuronectes platessa), dab (Limanda limanda) and cod (Gadus morhua) were isolated and incubated with different....... Biotransformations were also species dependent. The flatfish dab and plaice exhibited higher metabolic rates than cod (C) 1999 Elsevier Science Ltd. All rights reserved....
15. Hydrogen–Hydrogen Bonding in Planar Biphenyl, Predicted by Atoms-In-Molecules Theory, Does Not Exist
NARCIS (Netherlands)
Poater, J; Sola, M.; Bickelhaupt, F.M.
2006-01-01
Based on an Atoms-in-Molecules (AIM) analysis, Matta et al. (Chem. Eur. J.2003, 9, 1940) recently claimed evidence for the existence of hydrogen–hydrogen bonding between ortho-hydrogen atoms, pointing towards each other from adjacent phenyl groups in planar biphenyl. This AIM result is opposed to
16. Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and biphenyls (PCBs) in home-produced eggs
NARCIS (Netherlands)
Hoogenboom, L.A.P.; Dam, ten G.; Bruggen, van Mark; Jeurissen, Suzanne; Leeuwen, van S.P.J.; Theelen, R.M.C.; Zeilmaker, M.J.
2016-01-01
Home produced eggs from 62 addresses in the Netherlands were investigated for the levels of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and biphenyls (PCBs), both dioxin-like (dl) and non-dioxin-like (ndl). Compared to commercial eggs, levels were relatively high with a median of 4.6
17. A SIMPLE AND FAST EXTRACTION METHOD FOR ORGANOCHLORINE PESTICIDES AND POLYCHLORINATED BIPHENYLS IN SMALL VOLUMES OF AVIAN SERUM
Science.gov (United States)
A solid-phase extraction (SPE) method was developed using 8 M urea to desorb and extract organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs) from avian serum for analysis by capillary gas chromatography with electron capture detection (GC-ECD). The analytes were ...
18. Serum concentrations of polybrominated diphenyl ethers (PBDEs) and a polybrominated biphenyl (PBB) in men from Greenland, Poland and Ukraine
DEFF Research Database (Denmark)
Lenters, Virissa; Thomsen, Cathrine; Smit, Lidwien A M
2013-01-01
in Inuit men from across Greenland, and in men from Warsaw, Poland and Kharkiv, Ukraine. Serum was sampled between 2002 and 2004 from men 19 to 50years of age. 299 samples were analyzed for BDE-28, 47, 99, 100, 153, 154 and 183 and the brominated biphenyl BB-153 using gas chromatography-high resolution...
19. 21 CFR 509.15 - Use of polychlorinated biphenyls (PCB's) in establishments manufacturing food-packaging materials.
Science.gov (United States)
2010-04-01
... establishments manufacturing food-packaging materials. 509.15 Section 509.15 Food and Drugs FOOD AND DRUG... polychlorinated biphenyls (PCB's) in establishments manufacturing food-packaging materials. (a) Polychlorinated...). These accidents in turn caused the contamination of food products intended for human consumption (meat...
20. 21 CFR 109.15 - Use of polychlorinated biphenyls (PCB's) in establishments manufacturing food-packaging materials.
Science.gov (United States)
2010-04-01
... establishments manufacturing food-packaging materials. 109.15 Section 109.15 Food and Drugs FOOD AND DRUG... polychlorinated biphenyls (PCB's) in establishments manufacturing food-packaging materials. (a) Polychlorinated...). These accidents in turn caused the contamination of food products intended for human consumption (meat...
1. Polychlorinated biphenyl rhizoremediation by Pseudomonas fluorescens F113 derivatives, using a Sinorhizobium meliloti nod system to drive bph gene expression
Czech Academy of Sciences Publication Activity Database
Villacieros, M.; Whelan, C.; Macková, Martina; Molgaard, J.; Sánchez-Contreras, M.; Lloret, J.; Cárcer de, D.; Oruezábal, R. I.; Bolanos, L.; Macek, Tomáš; Karlson, U.; Dowling, D. N.; Martín, M.; Rivilla, R.
2005-01-01
Roč. 71, č. 5 (2005), 2687-2694 ISSN 0099-2240 Grant - others:5thFW(XE) QLK3-CT-2001-00101; European Commission(XE) BIO4-CT97-2227 Institutional research plan: CEZ:AV0Z4055905 Keywords : polychlorinated biphenyls * rhizoremediation Subject RIV: CC - Organic Chemistry Impact factor: 3.818, year: 2005
2. 77 FR 12836 - Draft Toxicological Review of Biphenyl: In Support of Summary Information on the Integrated Risk...
Science.gov (United States)
2012-03-02
... the draft human health assessment titled, Toxicological Review of Biphenyl: In Support of Summary... email: [email protected] . SUPPLEMENTARY INFORMATION: EPA's IRIS is a human health assessment... exposure to chemical substances found in the environment. Through the IRIS Program, EPA provides the...
3. Proof of concept for the use of macroinvertebrates as indicators of polychlorinated biphenyls (PCB) contamination in Lake Hartwell
Science.gov (United States)
James M. Lazorchak; Michael B. Griffith; Marc Mills; Joseph Schubauer-Berigan; Frank McCormick; Richard Brenner; Craig Zeller
2015-01-01
The US Environmental Protection Agency (USEPA) develops methods and tools for evaluating risk management strategies for sediments contaminated with polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and other legacy pollutants. Monitored natural recovery is a risk management alternative that relies on existing physical, chemical, and biological...
4. Environmental exposure to polychlorinated biphenyls (PCBs) and dioxins - Consequences for longterm neurological and cognitive development of the child. A Review
NARCIS (Netherlands)
Boersma, ER
2001-01-01
Polychlorinated biphenyl's (PCBs) and dioxins are environmental pollutants. Calculated on a body weight basis, prenatally as well as postnatally through breast-feeding, large amounts are transferred from mother to the child. Formula is free of these substances. Considering their potential
5. Effects of environmental exposure to polychlorinated biphenyls and dioxins on cognitive abilities in Dutch children at 42 months of age
NARCIS (Netherlands)
Patandin, S; Lanting, Caren; Mulder, PGH; Boersma, ER; Sauer, PJJ; Weisglas-Kuperus, N
Objective: To study possible adverse effects of environmental exposure to polychlorinated biphenyls (PCB) and dioxins on cognitive functioning in young children. Methods: In a follow-up of the Dutch PCB/Dioxin study, cognitive abilities were assessed with the Kaufman Assessment Battery for Children
6. First worldwide UNEP interlaboratory study on persistent organic pollutants (POPs) with data on polychlorinated biphenyls and organochlorine pesticides
NARCIS (Netherlands)
Leeuwen, van S.P.J.; Bavel, van B.; Boer, de J.
2013-01-01
The first worldwide interlaboratory study on persistent organic pollutants (POPs) under the Stockholm Convention was organized, with a participation of 103 laboratories from Asia, Europe, the Americas, Africa and Australia, of which the majority submitted data on polychlorinated biphenyls (PCBs) and
7. Levels of dioxin-like compounds in Taiwan foodstuffs
Energy Technology Data Exchange (ETDEWEB)
Hsu, M.S.; Wang, S.M.; Chou, U.; Chen, S.Y.; Huang, N.C.; Liao, G.Y.; Yu, T.P.; Ling, Y.C. [National Tsing Hua Univ., Hsinchu (Taiwan)
2004-09-15
Food is the major route of human intake of toxic dioxin-like compounds (DLCs), which include PolyChlorinated Dibenzo-p-Dioxins (PCDDs), PolyChlorinated DibenzoFurans (PCDFs), and WHO PolyChlorinated Biphenyls (PCBs). Approximately 95% of human DLCs exposure derives from food, with nearly 80% coming from food of animal origin. The DLCs levels in foodstuffs and the consumption rate of foodstuffs are essential to evaluate health risk posing to humans. The lack of DLCs levels in foodstuffs increases the population risk to DLCs exposure. The Department of Health, Taiwan has entrusted us to conduct a comprehensive monitoring program on PCDD/Fs levels in Taiwan foodstuffs in 2001 and 2002. In 2003, the program has extended the analytes to include 12 WHO-PCBs. The DLCs levels in Taiwan foodstuffs is, therefore, being surveyed for the first time.
8. Poly[(μ4-biphenyl-3,3′-dicarboxylatobis[μ2-1,1′-(butane-1,4-diyldiimidazole](μ2-oxalatodimanganese(II
Directory of Open Access Journals (Sweden)
Bao-Yong Zhu
2010-10-01
Full Text Available In the title coordination compound, [Mn2(C14H8O4(C2O4(C10H14N42]n, the biphenyl-3,3′-dicarboxylate and oxalate anions, both situated on inversion centres, function in a bridging mode, linking the dinuclear MnII atoms into wave-like layers. Each 1,1′-(1,4-butane-1,4-diyldiimidazole ligand coordinates to two MnII atoms located in adjacent layers via Mn—N coordination bonds, giving a three-dimensional network. As the methylene groups can bend freely relative to each other due to the C atoms connected via single bonds, the 1,1′-(butane-1,4-diyldiimidazole ligand forms an S-shaped conformation, which makes the void in the three-dimensional network distorted.
9. catena-Poly[[[aquasilver(I]-μ-1,1′-(butane-1,4-diyldi-1H-imidazole-κ2N3:N3′] hemi(biphenyl-4,4′-dicarboxylate dihydrate
Directory of Open Access Journals (Sweden)
Zheyu Zhang
2009-12-01
Full Text Available In the title compound, {[Ag(C10H14N4(H2O](C14H8O40.5·2H2O}n, the AgI ion is three-coordinated by two N atoms from two independent 1,1′-(butane-1,4-diyldi-1H-imidazole (BBI ligands and one water O atom in a distorted T-shaped coordination geometry. The biphenyl-4,4′-dicarboxylate (BPDC dianions do not coordinate to AgI ions but act as counter-ions. The AgI ions are linked by BBI ligands, forming a zigzag chain. These chains are linked into a two-dimensional supramolecular architecture by O—H...O hydrogen-bonding interactions between water molecules and carboxylate O atoms of the BPDC dianions.
10. Enhanced phytoremediation potential of polychlorinated biphenyl contaminated soil from e-waste recycling area in the presence of randomly methylated-β-cyclodextrins
International Nuclear Information System (INIS)
Shen Chaofeng; Tang Xianjin; Cheema, Sardar Alam; Zhang Congkai; Khan, Muhammad Imran; Liang Fang; Chen Xincai; Zhu Youfeng; Lin Qi; Chen, Yingxu
2009-01-01
The crude recycling of electronic and electric waste (e-waste) is now creating soil pollution problems with organic compounds such as polychlorinated biphenyls (PCBs). The present study aimed to compare the phytoremediation potential of four plant species (rice, alfalfa, ryegrass and tall fescue) for PCBs contaminated soil from Taizhou city, one of the largest e-waste recycling centers in China. In addition, the enhanced effects of randomly methylated-β-cyclodextrins (RAMEB) on PCBs phytoremediation potential were evaluated. Higher PCBs removal percentages of 25.6-28.5% in rhizosphere soil were observed after 120 days, compared with those of the non-rhizosphere (10.4-16.9%) and unplanted controls (7.3%). The average PCBs removal percentages of four plant species increased from 26.9% to 37.1% in the rhizosphere soil with addition of RAMEB. Meanwhile, relatively high microbial counts and dehydrogenase activity were detected in planted soils and a stimulatory effect by RAMEB addition was found. The present study indicated that all the plant candidates were feasible for phytoremediation of PCBs contaminated soil from the e-waste recycling area, and tall fescue with RAMEB amendment seemed as a promising remediation strategy. High PCBs removal percentage was due to the increased PCBs bioavailability as well as biostimulation of microbial communities after plantation and RAMEB addition.
11. Effects of urbanization on gaseous and particulate polycyclic aromatic hydrocarbons and polychlorinated biphenyls in a coastal city, China: levels, sources, and health risks.
Science.gov (United States)
Hong, Youwei; Chen, Jinsheng; Zhang, Fuwang; Zhang, Han; Xu, Lingling; Yin, Liqian; Chen, Yanting
2015-10-01
Gas/particle distributions of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were measured in Xiamen from May 2009 to March 2010 to evaluate the impacts of urbanization on the fate of persistent organic pollutants (POPs) in the atmospheric environment. In a newly developing area (NDA), the concentrations of 16 PAHs (gas + particle) were significantly higher than that a historically urbanized area (HUA) (p value <0.05), while the trend of 28 PCBs was reversed. Diagnostic ratios and principle component analysis (PCA) implied that atmospheric PAHs in the NDA were mainly derived from petrogenic combustion, including mixed sources of vehicle emissions, biomass burning and oil combustion, while pyrogenic combustion (e.g., traffic and coal combustion) was considered the major source of PAHs in the HUA. Atmospheric PCBs in both HUA and NDA were dominated by TriCBs and PeCBs related to the use of commercial mixtures (Aroclors 1242 and 1254). Based on the toxicological equivalent factor (TEF) approach, total benzo[a]pyrene equivalent values in the HUA and NDA were 1.12 and 2.02 ng m(-3), respectively, exceeding the standard threshold values (1.0 ng m(-3)) of China and WHO. Average daily intake of dioxin-like compounds was 0.2 pg kg(-1) day(-1) in the HUA, which are below the WHO tolerable daily intake level. The results showed that the contribution to the toxic equivalency (TEQ) was dominated by PCB169, PCB105, and PCB81.
12. Enhanced phytoremediation potential of polychlorinated biphenyl contaminated soil from e-waste recycling area in the presence of randomly methylated-{beta}-cyclodextrins
Energy Technology Data Exchange (ETDEWEB)
Shen Chaofeng [Institute of Environmental Science and Technology, Zhejiang University, Hangzhou 310029 (China); MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resources Science, Zhejiang University, Hangzhou 310029 (China); Tang Xianjin; Cheema, Sardar Alam; Zhang Congkai; Khan, Muhammad Imran; Liang Fang; Chen Xincai; Zhu Youfeng [Institute of Environmental Science and Technology, Zhejiang University, Hangzhou 310029 (China); Lin Qi, E-mail: linqi@zju.edu.cn [Institute of Environmental Science and Technology, Zhejiang University, Hangzhou 310029 (China); Chen, Yingxu [Institute of Environmental Science and Technology, Zhejiang University, Hangzhou 310029 (China)
2009-12-30
The crude recycling of electronic and electric waste (e-waste) is now creating soil pollution problems with organic compounds such as polychlorinated biphenyls (PCBs). The present study aimed to compare the phytoremediation potential of four plant species (rice, alfalfa, ryegrass and tall fescue) for PCBs contaminated soil from Taizhou city, one of the largest e-waste recycling centers in China. In addition, the enhanced effects of randomly methylated-{beta}-cyclodextrins (RAMEB) on PCBs phytoremediation potential were evaluated. Higher PCBs removal percentages of 25.6-28.5% in rhizosphere soil were observed after 120 days, compared with those of the non-rhizosphere (10.4-16.9%) and unplanted controls (7.3%). The average PCBs removal percentages of four plant species increased from 26.9% to 37.1% in the rhizosphere soil with addition of RAMEB. Meanwhile, relatively high microbial counts and dehydrogenase activity were detected in planted soils and a stimulatory effect by RAMEB addition was found. The present study indicated that all the plant candidates were feasible for phytoremediation of PCBs contaminated soil from the e-waste recycling area, and tall fescue with RAMEB amendment seemed as a promising remediation strategy. High PCBs removal percentage was due to the increased PCBs bioavailability as well as biostimulation of microbial communities after plantation and RAMEB addition.
13. Polychlorinated biphenyls in adult black bass and yellow perch were not associated with their reproductive success in the upper Hudson River, New York, USA.
Science.gov (United States)
Maceina, Michael J; Sammons, Steven M
2013-07-01
Although production and use of polychlorinated biphenyls (PCBs) ceased nearly 35 yr ago, questions still remain concerning the potential chronic effects these compounds may have on wild fish, including their reproductive success. In the upper Hudson River, New York, USA, fish were exposed to PCBs primarily from 2 manufacturing plants located approximately 320 km upstream of New York City, New York, from the 1940s to 1977. The authors collected yellow perch (Perca flavescens), smallmouth bass (Micropterus dolomieu), and largemouth bass (M. salmoides) using electrofishing, measured PCBs in these adults, and estimated abundance and size of their offspring at age 1 yr (age-1 fish). Fish were collected annually from 2004 to 2009 from 1 control site upstream of the PCB discharge sites and from 2 sites downstream from where PCBs were released. These sites (pools) are separated by a series of dams, locks, and canals. Muscle tissue wet weight PCB and lipid-based PCB concentrations in adults in the 2 PCB exposure pools averaged approximately 1 to 3 µg/g and 100 to 500 µg/g, respectively. Age-1 abundances were not related to adult PCB concentrations but were inversely related to river flow. Size of age-1 fish was slightly greater at the PCB-exposure sites. Levels of PCBs in yellow perch, largemouth bass, and smallmouth bass in the upper Hudson River did not impair or reduce recruitment or reproductive success. Copyright © 2013 SETAC.
14. Seasonal and spatial variability of polychlorinated biphenyls (PCBs) in vegetation and cow milk from a high altitude pasture in the Italian Alps
Energy Technology Data Exchange (ETDEWEB)
Tato, Liliana [Department of Biology, University of Milan, Via Celoria 26, Milan, I-20133 (Italy); Tremolada, Paolo, E-mail: paolo.tremolada@unimi.it [Department of Biology, University of Milan, Via Celoria 26, Milan, I-20133 (Italy); Ballabio, Cristiano [Department of Environmental and Land Sciences, University of Milano-Bicocca, Piazza Della Scienza 1, Milan, I-20126 (Italy); Guazzoni, Niccolo; Parolini, Marco; Caccianiga, Marco; Binelli, Andrea [Department of Biology, University of Milan, Via Celoria 26, Milan, I-20133 (Italy)
2011-10-15
The seasonal and spatial variability of polychlorinated biphenyls (PCBs) in vegetation and cow milk was studied in a high altitude pasture in the Alps (1900 m a.s.l.). PCB contamination in vegetation shows a concentration peak in June, which is mainly interpreted as the consequence of a temporary PCB enrichment of the air layer above the ground due to net emission fluxes from the soil. A three compartment dynamic model was developed to test this hypothesis. The North/South enrichment factor in the vegetation was 1.5-1.6 for penta- and hexa-substituted congeners and 1.7 for hepta- and octa-PCBs, according to the effect of temperature on compounds having higher K{sub oa} values. Milk concentrations followed the vegetation seasonal trend. The congener abundance in milk is in agreement with the biotransformation susceptibility, absorption efficiency and residence time of the different congeners in dairy cows. - Highlights: > A PCB peak in vegetation was found at the end of June. > Higher PCB concentrations in vegetation were found in the Northern aspect. > A temperature-dependent bioaccumulation process was found in the vegetation. > A direct transfer of PCBs was found from vegetation to dairy milk. > Carry-over ratios and bioaccumulation factors were calculated for dairy cow. - In a mountain pasture, PCBs concentrations in vegetation were found to be related to emission flux from soil and to the mean temperature of the site, and a direct transfer to milk was also observed.
15. An automated HPLC method for the fractionation of polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans in fish tissue on a porous graphitic carbon column
Science.gov (United States)
Echols, Kathy R.; Gale, Robert W.; Tillitt, Donald E.; Schwartz, Ted R.; O'Laughlin, Jerome
1997-01-01
The Ah (aryl-hydrocarbon) hydroxylase-receptor active polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were fractionated by an automated high-performance liquid chromatography (HPLC) system using the Hypercarb™ porous graphitic carbon (PGC) column. This commercially available column was used to fractionate the di-, mono-, and non-ortho PCBs into three fractions for gas chromatography (GC)/electron capture detection analysis, and a fourth fraction containing the PCDDs/PCDFs for GC/mass spectrometry analysis. The recoveries of the PCBs ranged from 68 to 96%, and recoveries of the PCDDs/PCDFs ranged from 74 to 123%. The PGC column has the advantage of faster separations (110 min versus 446 min) and less solvent use (275 ml versus 1,100 ml) compared with automated fractionation of these compounds on activated carbon (PX-21), while still affording good separation of the classes. The PGC column may have an advantage over the pyrenyl-based HPLC method because it has a greater loading capacity (400 μg total PCBs versus 250 μg). Overall, the PGC is a standard column that provides reproducible fractionation of PCDD/PCDFs and PCBs for analytical measurement in environmental samples.
16. Polybrominated, polychlorinated and monobromo-polychlorinated dibenzo-p-dioxins/dibenzofurans and dioxin-like polychlorinated biphenyls in marine surface sediments from Hong Kong and Korea
International Nuclear Information System (INIS)
Terauchi, Hidenori; Takahashi, Shin; Lam, Paul K.S.; Min, Byung-Yoon; Tanabe, Shinsuke
2009-01-01
In this study we investigated occurrences and distribution patterns of dioxin-related compounds (DRCs) such as polybrominated dibenzo-p-dioxins/dibenzofurans (PBDD/Fs), polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), monobromo-polychlorinated dibenzo-p-dioxins/dibenzofurans (MoBPCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in marine surface sediments collected from the coastal waters of Hong Kong and Korea. In most sampling sites, concentrations of PCDDs were the highest, followed by DL-PCBs, PCDFs, PBDFs, PBDDs, MoBPCDDs and MoBPCDFs in this order. Levels of PBDD/Fs were generally 1-2 orders of magnitude lower than chlorinated analogues. Levels of PCDDs are higher than PCDFs in Hong Kong while levels of PBDFs are higher than PBDDs in Korea (p < 0.05). Report of PBDD/Fs and MoBPCDD/Fs in sediments from East Asian countries is novel and original. Environmental levels of PBDD/Fs are supposed to start increasing in accordance with rising production, use and disposal of brominated flame retardants (BFRs) and recycling processes of e-waste in Asian developing countries. - Brominated and mixed halogenated dioxins/furans in Hong Kong and Korean waters are emitted from industrial activities
17. Impacts of urbanization on surface sediment quality: evidence from polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) contaminations in the Grand Canal of China.
Science.gov (United States)
Hong, Youwei; Yu, Shen; Yu, Guangbin; Liu, Yi; Li, Guilin; Wang, Min
2012-06-01
Organic pollutants, especially synthetic organic compounds, can indicate paces of anthropogenic activities. Effects of urbanization on polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) distributions in surface sediment were conducted in urban sections of the Grand Canal, China, consisting of a four-level urbanization gradient. The four-level urbanization gradients include three countryside towns, two small-size cities, three medium-size cities, and a large-size city. Diagnostic ratio analysis and factor analysis-multiple linear regression model were used for source apportionment of PAHs. Sediment quality guidelines (SQGs) of USA and Canada were employed to assess ecological risks of PAHs and PCBs in surface sediments of the Canal. Ranges of PAH and PCB concentrations in surface sediments were 0.66-22 mg/kg and 0.5-93 μg/kg, respectively. Coal-related sources were primary PAH sources and followed by vehicular emission. Total concentration, composition, and source apportionment of PAHs exhibited urbanization gradient effects. Total PCB concentrations increased with the urbanization gradient, while total PAHs concentration in surface sediments presented an inverted U Kuznets curve with the urbanization gradient. Elevated concentrations of both PAHs and PCBs ranged at effect range low levels or interim SQG, assessed by USA and Canadian SQGs. PAHs and PCBs in surface sediments of the Grand Canal showed urbanization gradient effects and low ecological risks.
18. Crystal structure of (E-1-(4′-methoxy-[1,1′-biphenyl]-4-yl-3-(3-nitrophenylprop-2-en-1-one
Directory of Open Access Journals (Sweden)
T. Vidhyasagar
2015-01-01
Full Text Available The title compound, C22H17NO4, crystallizes with two independent molecules (A and B in the asymmetric unit. Each molecule exists as an E isomer with C—C=C—C torsion angles of −175.69 (17 and −178.41 (17° in A and B, respectively. In molecule A, the planes of the terminal benzene rings are twisted by an angle of 26.67 (10°, while the biphenyl unit is non-planar, the dihedral angle between the rings being 30.81 (10°. The dihedral angle between the nitrophenyl ring and the inner phenyl ring is 6.50 (9°. The corresponding values in molecule B are 60.61 (9, 31.07 (8 and 31.05 (9°. In the crystal, molecules are arranged in a head-to-head manner, with the 3-nitrophenyl groups nearly parallel to one another. The A and B molecules are linked to one another via C—H...O hydrogen bonds, forming chains lying parallel to (-320 and enclosing R22(10 and R22(12 ring motifs. The methoxy group in both molecules is positionally disordered with a refined occupancy ratio of 0.979 (4:0.021 (4 for molecule A and 0.55 (4:0.45 (4 for molecule B.
19. Enhanced iodide sequestration by 3-biphenyl-5,6-dihydroimidazo 2,1-b thiazole in sodium/iodide sym-porter (NIS)-expressing cells
International Nuclear Information System (INIS)
Lecat-Guillet, N.; Ambroise, Y.
2008-01-01
The ability of the sodium/iodide sym-porter (NIS) to take up iodide has long provided the basis for cyto-reductive gene therapy and cancer treatment with radio-iodide. One of the major limitations of this approach is that radio-iodide retention in NIS-expressing cells is not sufficient for their destruction. We identified and characterized a small organic molecule capable of increasing iodide retention in HEK293 cells permanently transfected with human NIS cDNA (hNIS-HEK293) and in the rat thyroid-derived cell line FRTL-5. In the presence of 3-biphenyl-4'-yl-5,6-dihydroimidazo[2,1-b)thiazole (ISA1), the transmembrane iodide concentration gradient was increased up to 4.5-fold. Our experiments indicate that the imidazo-thiazole derivative acts either by inhibiting anion efflux mechanisms, or by promoting the relocation of iodide into subcellular compartments. This new compound is not only an attractive chemical tool to investigate the mechanisms of iodide flux at the cellular level, but also opens promising perspectives in the treatment of cancer after NIS gene transfer. (authors)
20. 3D multidisciplinary numerical model of polychlorinated biphenyl dynamics on the Black Sea north-western shelf
Science.gov (United States)
Bagaiev, Andrii; Ivanov, Vitaliy
2014-05-01
The Black Sea north-western shelf plays a key role in economics of the developing countries such as Ukraine due to food supply, invaluable recreational potential and variety of the relevant maritime shipping routes. On the other hand, a shallow flat shelf is mostly affected by anthropogenic pollution, eutrophication, hypoxia and harmful algae blooms. The research is focused on modeling the transport and transformation of PCBs (PolyChlorinated Biphenyls) because they are exceedingly toxic and highly resistant to degradation, hence cumulatively affect marine ecosystems. Being lipophilic compounds, PCBs demonstrate the distinguishing sorption/desorption activity taking part in the biogeochemical fluxes via the organic matter particles and sediments. In the framework of the research, the coastal in-situ data on PCB concentration in the water column and sediments are processed, visualized and analyzed. It is concluded that the main sources of PCBs are related to the Danube discharge and resuspension from the shallow-water sediments. Developed 3D numerical model is aimed at simulation of PCB contamination of the water column and sediment. The model integrates the full physics hydrodynamic block as well as modules, which describe detritus transport and transformation and PCB dynamics. Three state variables are simulated in PCB transport module: concentration in solute, on the settling particles of detritus and in the top layer of sediments. PCB adsorption/desorption on detritus; the reversible PCB fluxes at the water-sediment boundary; destruction of detritus are taken into consideration. Formalization of PCB deposition/resuspension in the sediments is adapted from Van Rijn's model of the suspended sediment transport. The model was spun up to reconstruct the short term scenario of the instantaneous PCB release from the St. George Arm of Danube. It has been shown that PCB transport on sinking detritus represents the natural buffer mechanism damping the spreading PCB
1. Polychlorinated biphenyls, glycaemia and diabetes in a population living in a highly polychlorinated biphenyls-polluted area in northern Italy: a cross-sectional and cohort study
Directory of Open Access Journals (Sweden)
Claudia Zani
2013-05-01
Full Text Available Background. Polychlorinated biphenyls (PCBs have been found to be associated with diabetes in some, but not all, studies performed so far. The aim of this study was to assess the association between PCB serum levels and glycaemia and diabetes in people living in Brescia, a highly industrialised PCB-polluted town in Northern Italy. Design and Methods. 527 subjects were enrolled in a cross-sectional population-based study: they were interviewed face-to-face in 2003 and also provided a blood sample under fasting conditions. The concentration of 24 PCB congeners was determined using gas-chromatography (GC/MS. Subsequently, all subjects were included in a follow-up (cohort study. According to the Local Health Authority health-care database, subjects were considered to be diabetic if they had diabetes at interview time (prevalent cases or during a 7-year follow-up (incident cases. Results. A total of 53 subjects (10.0% were diabetics: 28 had dia- betes at enrolment and other 25 developed the disease subsequently. Diabetes frequency increased according to the serum concentrations of total PCBs and single PCB congeners, but no association was found when estimates were adjusted for education, body mass index, age and gender by logistic regression analysis. Accordingly, glycaemia increased with PCB serum levels, but no association was observed when multiple regression analysis, including confounding factors, was performed. Conclusions. This study does not support the hypothesis that PCB environmental exposure is strictly associated with diabetes or glycaemia.
2. Radiocarbon content of synthetic and natural semi-volatile halogenated organic compounds
International Nuclear Information System (INIS)
Reddy, C.M.; Xu Li; Eglinton, T.I.; Boon, J.P.; Faulkner, D.J.
2002-01-01
New developments in molecular-level 14 C analysis techniques enable clues about natural versus commercial synthesis of trace organic contaminants. - Some halogenated organic compounds, such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polybrominated diphenyl ethers (PBDEs), have been suggested to have natural sources but separating these compounds from their commercially synthesized counterparts is difficult. Molecular-level 14 C analysis may be beneficial since most synthetic compounds are manufactured from petrochemicals ( 14 C-free) and natural compounds should have 'modern' or 'contemporary' 14 C levels. As a baseline study, we measured, for the first time, the 14 C abundance in commercial PCB and PBDE mixtures, a number of organochlorine pesticides, as well as one natural product 2-(3', 5'-dibromo-2'-methoxyphenoxy)-3,5-dibromoanisole. The latter compound was isolated from a marine sponge and is similar in structure to a PBDE. All of the synthetic compounds were 14 C-free except for the pesticide toxaphene, which had a modern 14 C abundance, as did the brominated natural compound. The result for toxaphene was not surprising since it was commercially synthesized by the chlorination of camphene derived from pine trees. These results suggest that measuring the 14 C content of halogenated organic compounds may be quite useful in establishing whether organic compounds encountered in the environment have natural or synthetic origins (or both) provided that any synthetic counterparts derive from petrochemical feedstock
3. Sanskrit Compound Processor
Science.gov (United States)
Kumar, Anil; Mittal, Vipul; Kulkarni, Amba
Sanskrit is very rich in compound formation. Typically a compound does not code the relation between its components explicitly. To understand the meaning of a compound, it is necessary to identify its components, discover the relations between them and finally generate a paraphrase of the compound. In this paper, we discuss the automatic segmentation and type identification of a compound using simple statistics that results from the manually annotated data.
4. Occupational exposure to endocrine-disrupting compounds and biliary tract cancer among men
DEFF Research Database (Denmark)
Ahrens, Wolfgang; Mambetova, Chinara; Bourdon-Raverdy, Nicole
2007-01-01
OBJECTIVES: This study investigated the association between cancer of the extrahepatic biliary tract and exposure to endocrine-disrupting compounds. METHODS: Altogether 183 men with histologically confirmed carcinoma of the extrahepatic biliary tract and 1938 matched controls were interviewed bet......-disrupting compounds in the workplace and the risk for cancer of the extrahepatic biliary tract among men, particularly for the extrahepatic bile duct and ampulla of Vater. Polychlorinated biphenyls could possibly be a strong risk factor. Udgivelsesdato: 2007-Oct......OBJECTIVES: This study investigated the association between cancer of the extrahepatic biliary tract and exposure to endocrine-disrupting compounds. METHODS: Altogether 183 men with histologically confirmed carcinoma of the extrahepatic biliary tract and 1938 matched controls were interviewed...
5. Halogenated organic compounds in archived whale oil: A pre-industrial record
International Nuclear Information System (INIS)
Teuten, Emma L.; Reddy, Christopher M.
2007-01-01
To provide additional evidence that several halogenated organic compounds (HOCs) found in environmental samples are natural and not industrially produced, we analyzed an archived whale oil sample collected in 1921 from the last voyage of the whaling ship Charles W. Morgan. This sample, which pre-dates large-scale industrial manufacture of HOCs, contained two methoxylated polybrominated diphenyl ethers (MeO-PBDEs), five halogenated methyl bipyrroles (MBPs), one halogenated dimethyl bipyrrole (DMBP), and tentatively one dimethoxylated polybrominated biphenyl (diMeO-PBB). This result indicates, at least in part, a natural source of the latter compounds. - Nine halogenated organic compounds have been detected in archived whale oil from the early 1920s
6. Halogenated organic compounds in archived whale oil: A pre-industrial record
Energy Technology Data Exchange (ETDEWEB)
Teuten, Emma L. [Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole, MA 02543 (United States)]. E-mail: emma.teuten@plymouth.ac.uk; Reddy, Christopher M. [Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole, MA 02543 (United States)]. E-mail: creddy@whoi.edu
2007-02-15
To provide additional evidence that several halogenated organic compounds (HOCs) found in environmental samples are natural and not industrially produced, we analyzed an archived whale oil sample collected in 1921 from the last voyage of the whaling ship Charles W. Morgan. This sample, which pre-dates large-scale industrial manufacture of HOCs, contained two methoxylated polybrominated diphenyl ethers (MeO-PBDEs), five halogenated methyl bipyrroles (MBPs), one halogenated dimethyl bipyrrole (DMBP), and tentatively one dimethoxylated polybrominated biphenyl (diMeO-PBB). This result indicates, at least in part, a natural source of the latter compounds. - Nine halogenated organic compounds have been detected in archived whale oil from the early 1920s.
7. Distribution characteristics of polychlorinated biphenyls (PCBs) in coastal areas of Okinawa Island, Japan
Institute of Scientific and Technical Information of China (English)
2007-01-01
Surface sediment and seawater samples were collected from coastal areas around Okinawa Island from September 2001 to May 2002. The samples were analyzed for total polychlorinated biphenyl (PCB) levels and homolog composition. The results show that total PCB levels ranged from 0.32 to 128.7 ng/g (dry wt.) in sediment and 1.59 to 2.48 ng/L in seawater. The levels exceed the Environmental Quality Standard (EQS) for water pollution of Japan. The distribution of PCB homolog showed different patterns in the sediments and seawaters. Penta-chlorobiphenyls (CBs) comprised the main congener group in seawater, while hexa-CBs were more abundant homologs in the sediments. The heavily contaminated sites featured higher CBs, including penta-CBs, hexa-CBs, and hepta-CBs, than those in less contaminated sites where tri-CBs dominated. This study provides current distribution and geochemical behavior of PCBs in the coastal areas around Okinawa Island.
8. Final report for Tank 100 Sump sludge (KON332) for polychlorinated biphenyl's (PCB)
International Nuclear Information System (INIS)
Fuller, R.K.
1998-01-01
Final Report for Tank 100 Sump Sludge (KON332) for Polychlorinated Biphenyl's (PCB) Sample Receipt Sample KON332 was received from Tank 100-Sump (WESF) on May 18, 1998. The laboratory number issued for this sample is S98BOO0207 as shown on the Request for Sample Analysis (RSA) form (Attachment 4). The sample breakdown diagram (Attachment 3) provides a cross-reference of customer sample identification to the laboratory identification number. Attachment 4 provides copies of the Request for Sample Analysis (RSA) and Chain of Custody (COC) forms. The sample was received in the laboratory in a 125-ml polybottle. Breakdown and subsampling was performed on June 6, 1998. PCB analysis was performed on the wet sludge. A discussion of the results is presented in Attachment 2. The 222-S extraction bench sheets are presented in Attachment 5. The PCB raw data are presented in Attachment 6
9. Polychlorinated biphenyls (PCBs) in recreational marina sediments of San Diego Bay, southern California.
Science.gov (United States)
Neira, Carlos; Vales, Melissa; Mendoza, Guillermo; Hoh, Eunha; Levin, Lisa A
2018-01-01
Polychlorinated biphenyl (PCB) concentrations were determined in surface sediments from three recreational marinas in San Diego Bay, California. Total PCB concentrations ranged from 23 to 153, 31-294, and 151-1387ngg -1 for Shelter Island Yacht Basin (SIYB), Harbor Island West (HW) and Harbor Island East (HE), respectively. PCB concentrations were significantly higher in HE and PCB group composition differed relative to HW and SIYB, which were not significantly different from each other in concentration or group composition. In marina sediments there was a predominance (82-85%) of heavier molecular weight PCBs with homologous groups (6CL-7CL) comprising 59% of the total. In HE 75% of the sites exceeded the effect range median (ERM), and toxicity equivalence (TEQ dioxin-like PCBs) values were higher relative to those of HW and SIYB, suggesting a potential ecotoxicological risk. Copyright © 2017 Elsevier Ltd. All rights reserved.
10. Problems with the polychlorinated biphenyls (PCB) in Mexico; Problematica de los bifenilos policlorados (BPC) en Mexico
Energy Technology Data Exchange (ETDEWEB)
Valle, Esteban; Cruz, Maria Guadalupe [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)
1997-12-31
A general overview is presented of the problems with the polychlorinated biphenyls (PCB) (askarels) in Mexico, which are mainly associated with the use of these substances in electric equipment; also, a profile of the causes why the PCBs have been classified as environmental toxic substances and a potential hazard for the health of human beings. [Espanol] Se presenta un panorama general de la problematica de bifenilos policlorados (BPC) (askareles) en Mexico, la cual esta asociada principalmente con el uso de estos compuestos en equipos electricos; asimismo, se describe una semblanza de las causas por las cuales se han catalogado a los BPC como sustancias toxicas ambientales y un peligro potencial para la salud de los seres humanos.
11. Partitioning of naphthalene, methylnaphthalenes and biphenyl between wastewater treatment sludges and water
International Nuclear Information System (INIS)
Southworth, G.R.; Keller, J.L.
1984-01-01
Partition coefficients (K/sub p/) describing the partitioning of naphthalene, methylnaphthalenes and biphenyl between organic-rich wastes and water were determined using 14 C-tracer techniques as well as high performance liquid chromatographic analysis of the wastes and their aqueous extracts. Results of the two procedures were in good agreement. The concentrations of the specific organics in the wastes were not good predictors of concentrations in aqueous extracts, since K/sub p/ varied among the materials tested. Predictions of k/sub p/ based on organic carbon content of the sludges were well below observed values. Oil content of the wastes and oil-water partition coefficients appeared to be important factors in determining K/sub p/. 11 references, 5 tables
12. Secondary sex ratio in relation to exposures to polychlorinated biphenyls, dichlorodiphenyl dichloroethylene and methylmercury
DEFF Research Database (Denmark)
Timmermann, Clara Amalie Gade; Choi, Anna L.; Petersen, Maria Skaalum
2017-01-01
This study was undertaken to assess the potential impact of maternal exposures to polychlorinated biphenyl (PCB), dichlorodiphenyl dichloroethylene (DDE) and methylmercury on the secondary sex ratios (the ratio of male to female live births) over a span of 23 years. The study includes prospective...... data from three Faroese birth cohorts, with a total of 2,152 healthy mother-child dyads recruited between 1986 and 2009. The Faroe Islands is a subarctic fishing community, where pilot whale meat and blubber are part of the traditional marine diet. Exposures were measured in maternal hair, serum...... or umbilical cord blood. Confounder adjusted logistic regression models were used to assess the associations between maternal exposures and the secondary sex ratio. A doubling in ΣPCB, p,p'-DDE and mercury concentrations were associated with increased odds by 8% (95% CI = 0-16%), 7% (95% CI = 0-14%) and 9% (95...
13. Solid phase extraction of polychlorinated biphenyls from water containing humic substances
Energy Technology Data Exchange (ETDEWEB)
Bonifazi, P.; Pierini, E.; Bruner, F. [Centro di Studio per la Chimica dellAmbiente e le Tecnologie Strumentali Avanzate dell Universita degli Studi di Urbino, Ist. di Scienze Chimiche (Italy)
1997-06-01
A study was carried out of the recovery by solid phase extraction of the eleven most toxic polychlorinated biphenyls from water containing humic acids. Experiments were performed using water polluted with a humic acid (sodium salt) concentration of 9-18 mg L{sup -1}. The effect of humic acids on the recoveries was noticeable, especially where the more chlorinated congeners were concerned. The effect was also evident with river water containing naturally dissolved humic acids. A method for destroying humic acids prior to extraction was applied. The recoveries after the destruction of humic acids were in the range of 90%, even in the case of river water, demonstrating the applicability of the method to real samples. (orig.)
14. Problems with the polychlorinated biphenyls (PCB) in Mexico; Problematica de los bifenilos policlorados (BPC) en Mexico
Energy Technology Data Exchange (ETDEWEB)
Valle, Esteban; Cruz, Maria Guadalupe [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)
1998-12-31
A general overview is presented of the problems with the polychlorinated biphenyls (PCB) (askarels) in Mexico, which are mainly associated with the use of these substances in electric equipment; also, a profile of the causes why the PCBs have been classified as environmental toxic substances and a potential hazard for the health of human beings. [Espanol] Se presenta un panorama general de la problematica de bifenilos policlorados (BPC) (askareles) en Mexico, la cual esta asociada principalmente con el uso de estos compuestos en equipos electricos; asimismo, se describe una semblanza de las causas por las cuales se han catalogado a los BPC como sustancias toxicas ambientales y un peligro potencial para la salud de los seres humanos.
15. Migration of CT triplet excitons in TCNB-biphenyl and TCNB-HMB crystals
Science.gov (United States)
Kozankiewicz, BolesAw
1994-01-01
Delayed fluorescence decay curves of charge transfer (CT) crystals of tetracyanobenzene with biphenyl (TCNB-B) and with hexamethylbenzene (TCNB-HMB) have been studied over a wide temperature range (5-200 K). The decay curves have been adequately described by decay expressions derived for different mechanisms of triplet-triplet annihilation. This analysis points to one-dimensional, thermally activated motion of CT triplet excitons. The estimated activation energies for the exciton hopping are 360±60 and 650±100 cm -1 (or 550±150 cm -1 depending on the applied model) for the TCNB-B and TCNB-HMB crystals, respectively. The results seem to confirm the self-trapping of triplet CT excitons.
16. Temporal Trends of Hexabromocyclododecane, Polybrominated Diphenyl Ethers and Polychlorinated Biphenyls in Ringed Seals from East Greenland
DEFF Research Database (Denmark)
Vorkamp, Katrin; Riget, Frank Farsø; Bossi, Rossana
2011-01-01
also was found for adult seals with a time trend starting in 1994. ΣPCB decreased significantly in juvenile seals, again due to the 1986 value, while no trend was found for the adult animals. This indicates stagnating PCB concentrations at a relatively high level, in some cases possibly exceeding......Concentrations of hexabromocyclododecane (HBCD) were determined in a combination of archived and fresh blubber samples of juvenile ringed seals from East Greenland collected between 1986 and 2008. R-HBCD was the only diastereoisomer consistently above levels of quantification and showed...... on polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) have been extended with new data for 2006 and 2008. ΣPBDE in juvenile seals was the only parameter with a slight upward trend, however, dependent on the low 1986 concentration. Removing this data point resulted in a downward trend, which...
17. Polychlorinated biphenyls alter expression of alpha-synuclein, synaptophysin and parkin in the rat brain
DEFF Research Database (Denmark)
Malkiewicz, Katarzyna; Mohammed, Roma; Folkesson, Ronnie
2006-01-01
Polychlorinated Biphenyls (PCBs)-induced changes in synaptic transmission are one of the effects of their neurotoxicity but the mechanism remains unknown. We assessed the in vivo effects of the PCBs mixture, Aroclor 1254 on the expression of neuronal proteins that are involved in the synaptic...... function and/or are associated with neurodegeneration. Wistar rats were treated orally with repeated doses of Aroclor 1254 and the levels of soluble alpha-synuclein, parkin, synaptophysin and amyloid precursor protein (APP) in the brain were determined by Western blotting. The results showed that Aroclor...... did not cause changes in the expression and processing of APP but at a dose 100 microg/g/day repeated for 6 days caused a decrease in the expression of alpha-synuclein in the cerebellum, cortex, hippocampus and hypothalamus of the animals sacrificed 2 days after treatment. The decrease in alpha...
18. Tissue deposition of polychlorinated biphenyls in cats fed Atlantic Ocean bluefish.
Science.gov (United States)
Carbone, L G; Alo, D K; Scarlett, J M; Gutenmann, W H; Lisk, D J
1991-07-01
Bluefish (Pomatomus saltatrix), a very popular marine sport fish caught in Atlantic coastal waters, contain significant levels of polychlorinated biphenyls (PCBs). Since fish can be an appreciable portion of human and feline diets, a feeding study was conducted with cats fed exclusively bluefish for 86 days with determination of tissue concentrations of PCBs. The concentrations of PCBs in brain, liver, and fat were significantly higher (p = 0.01) in the fish-fed cats than in the control group using the Wilcoxon rank sum test. The highest PCB levels were in fat, the median concentrations being 48 and 0.61 ppm (dry weight) in the fish-fed and control cats, respectively. The significance of the results is discussed.
19. Blarina brevicauda as a biological monitor of polychlorinated biphenyls: evaluation of hepatic cytochrome P450 induction.
Science.gov (United States)
Russell, Julie S; Halbrook, Richard S; Woolf, Alan; French, John B; Melancon, Mark J
2004-08-01
We assessed the value of short-tailed shrews (Blarina brevicauda) as a possible biomonitor for polychlorinated biphenyl pollution through measurement of the induction of hepatic cytochrome P450 and associated enzyme activities. First, we checked the inducibility of four monooxygenases (benzyloxyresorufin-O-dealkylase [BROD], ethoxyresorufin-O-dealkylase [EROD], methoxyresorufin-O-dealkylase [MROD], and pentoxyresorufin-O-dealkylase [PROD]) by measuring the activity of these enzymes in hepatic microsomes prepared from shrews injected with beta-naphthoflavone (betaNF) or phenobarbital (PB), typical inducers of cytochrome P4501A (CYP1A) and CYP2B enzyme families, respectively. Enzyme activity was induced in shrews that received betaNF but not in shrews that received PB; PROD was not induced by either exposure. Later, shrews were exposed to a mixture of polychlorinated biphenyls (PCBs) (Aroclor 1242:1254, in 1:2 ratio) at 0.6, 9.6, and 150 ppm in food, for 31 d. Induction in these shrews was measured by specific enzyme activity (BROD, EROD, and MROD) in hepatic microsomes, by western blotting of solubilized microsomes against antibodies to CYP1A or CYP2B, and by duration of sodium pentobarbital-induced sleep. These three CYP enzymes were induced in shrews by PCBs at similar levels of exposure as in cotton rat (Sigmodon hispidus). Neither sleep time nor the amount of CYP2B family protein were affected by PCB exposure. Blarina brevicauda can be a useful biomonitor of PCBs that induce CYP1A, especially in habitats where they are the abundant small mammal.
20. Sex dependence of the components and structure of urinary calculi induced by biphenyl administration in rats.
Science.gov (United States)
Ohnishi, M; Yajima, H; Yamamoto, S; Matsushima, T; Ishii, T
2000-08-01
To obtain definitive information about the mechanisms of urinary calculus formation and the structural characteristics of the calculi induced by biphenyl administration in rats, with a focus on the sex dependency, the constituents of the urinary calculi were analyzed by HPLC, inductively coupled plasma spectroscopy (ICP), micro Fourier transform infrared spectroscopy (mFT-IR), and ion chromatography (IC), and structural analyses were carried out by microscopy, mFT-IR, and the electron probe microanalyzer (EPMA) method. We attempted to account for the appreciably higher incidence of calculi in males than in females. mFT-IR analysis revealed that the biphenyl-induced urinary calculi in male rats are composed mainly of potassium 4-hydroxybiphenyl-o-sulfate (4-HBPOSK), whereas the calculi in female rats are composed mainly of 4-hydroxybiphenyl (4-HBP) and KHSO(4) produced by the hydrolysis of 4-HBPOSK. Observations of photomicrographs and the results of mFT-IR analysis indicated that the calculi in males have a multilayer structure consisting of alternating layers of 4-HBPOSK and calcium phosphate, whereas the calculi in females have no multilayer structure, but open holes in which needle-shaped crystals are present in some places. In view of the results of these analyses, including the EPMA analysis, it appears that calculus formation in males may involve a series of successive and irreversible reactions, whereas calculus formation in females may result from a series of reversible reactions, including the hydrolysis of 4-HBPOSK. It was inferred that the series of irreversible reactions involved in calculus formation in males is relatively more stable than that in the case of females, and thus, a sex difference in the reaction features may be responsible for the observed difference in the incidence of calculus formation.
1. Assessment of polychlorinated biphenyls and organochlorine pesticides in water samples from the Yamuna River
Directory of Open Access Journals (Sweden)
Bhupander Kumar
2012-07-01
Full Text Available Polychlorinated biphenyls (PCBs, hexachlorocyclohexane (HCH and dichlorodiphenyltrichloroethane (DDT are toxic, persistent and bioaccumulative long-range atmospheric transport pollutants. These are transported worldwide affecting remote regions far from their original sources, and can transfer into food webs with a wide range of acute and chronic health effects. India ratified the Stockholm Convention with the intention of reducing and eliminating persistent organic pollutants (POPs, and encouraged the support of research on POPs. Despite the ban and restriction on the use of these chemicals in India, their contamination of air, water, sediment, biota and humans has been reported. In this study, surface water samples were collected during January 2012 from the Yamuna River in Delhi, India, and analyzed for PCBs and organochlorine pesticides (OCPs. The concentrations of ΣPCBs and ΣOCPs ranged between 2-779 ng L–1 and from less than 0.1 to 618 ng L–1 (mean 99±38 ng L–1 and 221±50 ng L–1, respectively. The PCB homolog was dominated by 3-4 chlorinated biphenyls. In calculating the toxicity equivalent of dioxin-like PCBs (dl-PCBsusing World Health Organization toxic equivalency factors, dl-PCBs accounted for 10% of a total of 27 PCBs. The concentration of ΣHCH ranged between less than 0.1 and 285 ng L–1 (mean 151±32 ng L–1. However, ΣDDTs concentrations varied between less than 0.1 and 354 ng L–1 (mean 83±26 ng L–1. The concentrations were lower than the US guideline values; however, levels of lindane exceeded those recommended in guidelines. Further in-depth study is proposed to determine the bioaccumulation of these pollutants through aquatic biota to assess the risk of contaminants to human health.
2. Chlorinated hydrocarbon pesticides and polychlorinated biphenyls in sediment cores from San Francisco Bay
Science.gov (United States)
Venkatesan, M.I.; De Leon, R. P.; VanGeen, A.; Luoma, S.N.
1999-01-01
Sediment cores of known chronology from Richardson and San Pablo Bays in San Francisco Bay, CA, were analyzed for a suite of chlorinated hydrocarbon pesticides and polychlorinated biphenyls to reconstruct a historic record of inputs. Total DDTs (DDT = 2,4'- and 4,4'-dichlorodiphenyltrichloroethane and the metabolites, 2,4'- and 4,4'-DDE, -DDD) range in concentration from 4-21 ng/g and constitute a major fraction (> 84%) of the total pesticides in the top 70 cm of Richardson Bay sediment. A subsurface maximum corresponds to a peak deposition date of 1969-1974. The first measurable DDT levels are found in sediment deposited in the late 1930's. The higher DDT inventory in the San Pablo relative to the Richardson Bay core probably reflects the greater proximity of San Pablo Bay to agricultural activities in the watershed of the Sacramento and San Joaquin rivers. Total polychlorinated biphenyls (PCBs) occur at comparable levels in the two Bays (inventories in San Pablo Bay are about a factor of four higher in the last four decades than in Richardson Bay, suggesting a distribution of inputs not as strongly weighed towards the upper reaches of the estuary as DDTs. The shallower subsurface maximum in PCBs compared to DDT in the San Pablo Bay core is consistent with the imposition of drastic source control measures four these constituents in 1970 and 1977 respectively. The observed decline in DDT and PCB levels towards the surface of both cores is consistent with a dramatic drop in the input of these pollutants once the effect of sediment resuspension and mixing is taken into account.
3. Bioaugmentation of a historically contaminated soil by polychlorinated biphenyls with Lentinus tigrinus
Directory of Open Access Journals (Sweden)
Federici Ermanno
2012-03-01
Full Text Available Abstract Background Several species belonging to the ecological group of white-rot basidiomycetes are able to bring about the remediation of matrices contaminated by a large variety of anthropic organic pollutants. Among them, polychlorobiphenyls (PCBs are characterized by a high recalcitrance due to both their low bioavailability and the inability of natural microbial communities to degrade them at significant rates and extents. Objective of this study was to assess the impact of a maize stalk-immobilized Lentinus tigrinus CBS 577.79 inoculant combined with soybean oil (SO, as a possible PCB-mobilizing agent, on the bioremediation and resident microbiota of an actual Aroclor 1260 historically contaminated soil under unsaturated solid-phase conditions. Results Best overall PCB depletions (33.6 ± 0.3% and dechlorination (23.2 ± 1.3% were found after 60 d incubation in the absence of SO where, however, the fungus appeared to exert adverse effects on both the growth of biphenyl- and chlorobenzoate-degrading bacteria and the abundance of genes coding for both biphenyl dioxygenase (bph and catechol-2,3-dioxygenase. A significant (P bph. Conclusions The PCB depletion extents obtained in the presence of L. tigrinus are by far higher than those reported in other remediation studies conducted under unsaturated solid phase conditions on actual site soils historically contaminated by Aroclor 1260. These results suggest that the bioaugmentation strategy with the maize stalk-immobilized mycelium of this species might be promising in the reclamation of PCB-contaminated soils. The addition of SO to matrices contaminated by technical PCB mixtures, such as Aroclor 1242 and Delor 103 and characterized by a large preponderance of low chlorinated congeners, might not be advisable.
4. The Need and Potential of Biosensors to Detect Dioxins and Dioxin-Like Polychlorinated Biphenyls along the Milk, Eggs and Meat Food Chain
Directory of Open Access Journals (Sweden)
Aize Kijlstra
2011-12-01
Full Text Available Dioxins and dioxin-like polychlorinated biphenyls (DL-PCBs are hazardous toxic, ubiquitous and persistent chemical compounds, which can enter the food chain and accumulate up to higher trophic levels. Their determination requires sophisticated methods, expensive facilities and instruments, well-trained personnel and expensive chemical reagents. Ideally, real-time monitoring using rapid detection methods should be applied to detect possible contamination along the food chain in order to prevent human exposure. Sensor technology may be promising in this respect. This review gives the state of the art for detecting possible contamination with dioxins and DL-PCBs along the food chain of animal-source foods. The main detection methods applied (i.e., high resolution gas-chromatography combined with high resolution mass-spectrometry (HRGC/HRMS and the chemical activated luciferase gene expression method (CALUX bioassay, each have their limitations. Biosensors for detecting dioxins and related compounds, although still under development, show potential to overcome these limitations. Immunosensors and biomimetic-based biosensors potentially offer increased selectivity and sensitivity for dioxin and DL-PCB detection, while whole cell-based biosensors present interpretable biological results. The main shortcoming of current biosensors, however, is their detection level: this may be insufficient as limits for dioxins and DL-PCBs for food and feedstuffs are in pg per gram level. In addition, these contaminants are normally present in fat, a difficult matrix for biosensor detection. Therefore, simple and efficient extraction and clean-up procedures are required which may enable biosensors to detect dioxins and DL-PCBs contamination along the food chain.
5. The Need and Potential of Biosensors to Detect Dioxins and Dioxin-Like Polychlorinated Biphenyls along the Milk, Eggs and Meat Food Chain
Science.gov (United States)
Chobtang, Jeerasak; de Boer, Imke J. M.; Hoogenboom, Ron L. A. P.; Haasnoot, Willem; Kijlstra, Aize; Meerburg, Bastiaan G.
2011-01-01
Dioxins and dioxin-like polychlorinated biphenyls (DL-PCBs) are hazardous toxic, ubiquitous and persistent chemical compounds, which can enter the food chain and accumulate up to higher trophic levels. Their determination requires sophisticated methods, expensive facilities and instruments, well-trained personnel and expensive chemical reagents. Ideally, real-time monitoring using rapid detection methods should be applied to detect possible contamination along the food chain in order to prevent human exposure. Sensor technology may be promising in this respect. This review gives the state of the art for detecting possible contamination with dioxins and DL-PCBs along the food chain of animal-source foods. The main detection methods applied (i.e., high resolution gas-chromatography combined with high resolution mass-spectrometry (HRGC/HRMS) and the chemical activated luciferase gene expression method (CALUX bioassay)), each have their limitations. Biosensors for detecting dioxins and related compounds, although still under development, show potential to overcome these limitations. Immunosensors and biomimetic-based biosensors potentially offer increased selectivity and sensitivity for dioxin and DL-PCB detection, while whole cell-based biosensors present interpretable biological results. The main shortcoming of current biosensors, however, is their detection level: this may be insufficient as limits for dioxins and DL-PCBs for food and feedstuffs are in pg per gram level. In addition, these contaminants are normally present in fat, a difficult matrix for biosensor detection. Therefore, simple and efficient extraction and clean-up procedures are required which may enable biosensors to detect dioxins and DL-PCBs contamination along the food chain. PMID:22247688
6. Gas chromatography/atmospheric pressure chemical ionization/mass spectrometry for the analysis of organochlorine pesticides and polychlorinated biphenyls in human serum.
Science.gov (United States)
Geng, Dawei; Jogsten, Ingrid Ericson; Dunstan, Jody; Hagberg, Jessika; Wang, Thanh; Ruzzin, Jerome; Rabasa-Lhoret, Rémi; van Bavel, Bert
2016-07-01
A method using a novel atmospheric pressure chemical ionization source for coupling gas chromatography (GC/APCI) to triple quadrupole mass spectrometry (MS/MS) for the determination of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) regulated by the Stockholm Convention is presented. One microliter injection of a six-point calibration curve of native PCBs and OCPs, ranging from 0.04 to 300pg/μL, was performed. The relative standard deviation (RSD) of the relative response factors (RRFs) was less than 15% with a coefficient of determination (r(2))>0.995. Meanwhile, two calibration solutions (CS), CS 2 (0.4pg/μL) and CS 3 (4pg/μL) were analyzed to study the repeatability calculated for both area and RRFs. The RSD for RRF ranged from 3.1 to 16% and 3.6 to 5.5% for CS 2 and CS 3, respectively. The limits of detection (LOD) determined by peak-to-peak signal-to-noise ratio (S/N) of 3 were compared between the GC/APCI/MS/MS and a GC coupled to high resolution mass spectrometry (GC/HRMS) system. GC/APCI/MS/MS resulted in lower LOD for most of the compounds, except for PCB#74, cis-chlordane and trans-chlordane. GC/APCI/MS/MS and GC/HRMS were also compared by performing analysis on 75 human serum samples together with eight QA/QC serum samples. The comparison between GC/APCI/MS/MS system and GC/HRMS system for 16 of the targeted compounds was carried out. No statistically significant difference was discovered. Due to increased sensitivity and user friendly operation under atmospheric pressure, GC/APCI/MS/MS is a powerful alternative technique that can easily meet the specification of GC/HRMS. Copyright © 2016 Elsevier B.V. All rights reserved.
7. The need and potential of biosensors to detect dioxins and dioxin-like polychlorinated biphenyls along the milk, eggs and meat food chain.
Science.gov (United States)
Chobtang, Jeerasak; de Boer, Imke J M; Hoogenboom, Ron L A P; Haasnoot, Willem; Kijlstra, Aize; Meerburg, Bastiaan G
2011-01-01
Dioxins and dioxin-like polychlorinated biphenyls (DL-PCBs) are hazardous toxic, ubiquitous and persistent chemical compounds, which can enter the food chain and accumulate up to higher trophic levels. Their determination requires sophisticated methods, expensive facilities and instruments, well-trained personnel and expensive chemical reagents. Ideally, real-time monitoring using rapid detection methods should be applied to detect possible contamination along the food chain in order to prevent human exposure. Sensor technology may be promising in this respect. This review gives the state of the art for detecting possible contamination with dioxins and DL-PCBs along the food chain of animal-source foods. The main detection methods applied (i.e., high resolution gas-chromatography combined with high resolution mass-spectrometry (HRGC/HRMS) and the chemical activated luciferase gene expression method (CALUX bioassay)), each have their limitations. Biosensors for detecting dioxins and related compounds, although still under development, show potential to overcome these limitations. Immunosensors and biomimetic-based biosensors potentially offer increased selectivity and sensitivity for dioxin and DL-PCB detection, while whole cell-based biosensors present interpretable biological results. The main shortcoming of current biosensors, however, is their detection level: this may be insufficient as limits for dioxins and DL-PCBs for food and feedstuffs are in pg per gram level. In addition, these contaminants are normally present in fat, a difficult matrix for biosensor detection. Therefore, simple and efficient extraction and clean-up procedures are required which may enable biosensors to detect dioxins and DL-PCBs contamination along the food chain.
8. A cohort study of the association between secondary sex ratio and parental exposure to polybrominated biphenyl (PBB and polychlorinated biphenyl (PCB
Directory of Open Access Journals (Sweden)
Terrell Metrecia L
2009-08-01
Full Text Available Abstract Background Polybrominated biphenyl (PBB, a brominated flame retardant, was accidently mixed into animal feed in Michigan (1973–1974 resulting in human exposure through consumption of contaminated meat, milk and eggs. Beginning in 1976 individuals who consumed contaminated products were enrolled in the Michigan Long-Term PBB Study. This cohort presents a unique opportunity to study the association between parental exposures to PBB and offspring sex ratio. Methods We identified offspring of female PBB cohort participants (born 1975–1988 and obtained electronic birth records for those born in the state of Michigan. We linked this information to parental serum PBB and PCB concentrations collected at enrollment into the cohort. We modeled the odds of a male birth with generalized estimating equations accounting for the non-independence of siblings born to the same parents. We explored potential confounders: parental age and education at offspring's birth, parental body mass index at cohort enrollment, birth order, gestational age and year of offspring's birth. Results The overall proportion of male offspring among 865 live births to cohort mothers was 0.542. This was higher than the national male proportion of 0.514 (binomial test: p = 0.10. When both parents were in the cohort (n = 300, we found increased odds of a male birth with combined parents' enrollment PBB exposure ≥ the median concentrations (3 μg/L for mothers; 6 μg/L for fathers compared to combined parents' PBB exposure Conclusion This study adds to the body of literature on secondary sex ratio and exposure to environmental contaminants. In this population, combined parental exposure to PBBs or PCBs increased the odds of a male birth. Further research is needed to corroborate these findings and shed light on the biological mechanisms by which these types of chemicals may influence the secondary sex ratio.
9. SIMPLE METHOD FOR ESTIMATING POLYCHLORINATED BIPHENYL CONCENTRATIONS ON SOILS AND SEDIMENTS USING SUBCRITICAL WATER EXTRACTION COUPLED WITH SOLID-PHASE MICROEXTRACTION. (R825368)
Science.gov (United States)
A rapid method for estimating polychlorinated biphenyl (PCB) concentrations in contaminated soils and sediments has been developed by coupling static subcritical water extraction with solid-phase microextraction (SPME). Soil, water, and internal standards are placed in a seale...
10. Polychlorinated Biphenyls (PCBs) and Polybrominated Diphenol Ethers (PBDEs) in Current and Historical Samples of Avian Eggs from Nesting Sites in Buzzards Bay, MA, USA
Science.gov (United States)
We measured concentrations of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in eggs from breeding colonies in Buzzards Bay, MA, USA. Eggs from two piscivorous bird species, common (Sterna hirundo) and roseate (Sterna dougallii) terns, were collected...
11. Temperature-controlled two new Co(II) compounds with distinct topological networks: Syntheses, crystal structures and catalytic properties
Science.gov (United States)
Meng, Qing-Hua; Long, Xu; Liu, Jing-Li; Zhang, Shuan; Zhang, Guang-Hui
2018-04-01
Two new Co(II) coordination compounds, namely [Co2(bptc)(bpp)2]n (1) and [Co(bptc)0.5(bpp)]n (2) (H4bptc = biphenyl-3,3‧,5,5‧-tetracarboxylic acid, bpp = 1,3-di(4-pyridyl)propane), have been hydrothermally synthesized from the same reactants via tuning the reaction temperature. Single crystal X-ray diffraction analyses revealed that both 1 and 2 feature 2D sheet motifs. Topological analyses revealed that compounds 1 and 2 show distinct topological networks. Under the weak Van der Waals interactions, the 2D sheet motifs of compounds 1 and 2 are further packed into 2D→3D interdigitated supramolecular frameworks. Moreover, the two Co(II) compounds show high catalytic activities for degradation of methyl orange (MO) in a Fenten-like process.
12. Photoluminescence and electroluminescence of a tripodal compound containing 7-diethylamino-coumarin moiety
Energy Technology Data Exchange (ETDEWEB)
Yu Tianzhi; Zhang Peng; Zhang Hui; Meng Jing; Fan Duowang [Key Laboratory of Opto-Electronic Technology and Intelligent Control (Lanzhou Jiaotong University), Ministry of Education, Lanzhou 730070 (China); Zhao Yuling; Dong Wenkui [School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou 730070 (China)], E-mail: ytz823@hotmail.com
2008-12-07
A novel tripodal compound, tris[2-(7-diethylamino-coumarin-3-carboxamide)ethyl]amine (Tren-C), was synthesized and characterized by elemental analysis, infrared and {sup 1}H-NMR spectra. The photoluminescent (PL) and electroluminescent properties of Tren-C were investigated. Tren-C exhibits different colour emissions in solid states and solutions. The electroluminescence devices comprising vacuum vapour-deposited films using the compound as a dopant were fabricated, showing blue emissions that are identical to its PL spectrum in chloroform solutions. With the device structure of indium tin oxide (ITO)/4, 4', 4''-tris-N-naphthyl-N-phenylamino-triphenylamine (2-TNATA) (5 nm)/N, N'-bis-(naphthyl)-N, N'-diphenyl-1, 1'-biphenyl-4, 4'-diamine (NPB) (40 nm)/4, 4'-bis(9-carbazolyl) biphenyl (CBP) : Tren-C (0.5 wt%, 30 nm)/2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1, 3, 4-oxadiazole (Bu-PBD) (30 nm)/LiF (1 nm)/Al (100 nm), a maximum external quantum efficiency of 2.85%, a maximum luminous efficiency of 3.85 cd A{sup -1} and a maximum luminance of 1450 cd m{sup -2} are realized.
13. Concentration and distribution of dioxins and related compounds in various human organs
Energy Technology Data Exchange (ETDEWEB)
Iida, T.; Hirakawa, H.; Hori, T.; Tobiishi, K.; Matsueda, T. [Fukuoka Inst. of Health and Environmental Sciences, Dazaifu, Fukuoka (Japan); Todaka, T. [Japan Food Hygiene Association, Tokyo (Japan); Watanabe, S. [Tokyo Univ. of Agriculture, Tokyo (Japan); Yamada, T. [Keio Univ. School of Medicine, Tokyo (Japan)
2004-09-15
Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and non-ortho coplanar polychlorinated biphenyls (Non-Co-PCBs) and mono-ortho coplanar polychlorinated biphenyls (Mono-Co-PCBs) accumulate in the human body due to their highly lipophilic properties. In recent years, there has been some concern about the potential health effects of dioxins and related chemicals for the general population of humans. Although there exists an enormous amount of data on this subject, most of it is from breast milk and blood, due to ease of collection; information concerning concentrations and distribution in various human organs hardly exists. Therefore, new data concerning various human tissues is required to evaluate the pathophysiological significance of dioxins and related compounds in humans. The aim of this study was to investigate the concentration levels and distribution of dioxins and related compounds in various human organ tissues. We previously reported on the concentration levels in the human liver and adipose tissues from 28 donors. In this paper, we determined the concentrations of dioxin-like isomers in 8 organs, including blood, lungs, liver, bile, spleen, pancreas, kidney and mesentery fat from 20 donors.
14. Alteration of General Behavior of Male Medaka,oryzias latipes,Exposed to Tributyltin and /or Polychlorinated Biphenyls
OpenAIRE
Nakayama, Kei; Oshima, Yuji; Hiramatsu, Kazuaki; Honjo, Tsuneo
2004-01-01
We examined the general behavior of male Japanese medaka, Oryzias latipes, after exposed to tributyltin (TBT), polychlorinated biphenyls (PCBs), or a mixture of these chamicals at a concentration of 1μg/g body weight daily for 3 weeks. We analyzed swimming velocity as an indicator of acute toxicity and counted the frequencies of straight swimming and swimming in circles. We also calclated the entropy of the positions of the fish within the experimental chamber. Neither TBT nor PCBs nor their ...
15. Congener-specific polychlorinated biphenyl patterns in eggs of aquatic birds from the lower Laguna Madre, Texas
Science.gov (United States)
Mora, Miguel A.
1996-01-01
Eggs from four aquatic bird species nesting in the Lower Laguna Madre, Texas, were collected to determine differences and similarities in the accumulation of congener-specific polychlorinated biphenyls (PCBs) and to evaluate PCB impacts on reproduction. Because of the different toxicities of PCB congeners, it is important to know which congeners contribute most to total PCBs. The predominant PCB congeners were 153, 138, 180, 110, 118, 187, and 92. Collectively, congeners 153, 138, and 180 accounted for 26 to 42% of total PCBs. Congener 153 was the most abundant in Caspian terns (Sterna caspia) and great blue herons (Ardea herodias) and congener 138 was the most abundant in snowy egrets (Egretta thula) and tricolored herons (Egretta tricolor). Principal component analysis indicated a predominance of higher chlorinated biphenyls in Caspian terns and great blue herons and lower chlorinated biphenyls in tricolored herons. Snowy egrets had a predominance of pentachlorobiphenyls. These results suggest that there are differences in PCB congener patterns in closely related species and that these differences are more likely associated with the species' diet rather than metabolism. Total PCBs were significantly greater (p birds from the Lower Laguna Madre were below concentrations known to affect bird reproduction.
16. Magnetoelectrochemistry of 4,4'-bis(dimethylamino)biphenyl and 4,4'-dinitrobiphenyl azacrown macrocyclic lactams
Energy Technology Data Exchange (ETDEWEB)
Domenech, Antonio [Departament de Quimica Analitica, Universitat de Valencia, Dr. Moliner 50, 46100 Burjassot, Valencia (Spain); Costero, Ana Maria; Banuls, Maria Jose; Aurell, Maria Jose [Departament de Quimica Organica, Universitat de Valencia, Dr. Moliner 50, 46100 Burjassot, Valencia (Spain)
2005-07-25
The voltammetric behaviour at carbon fibre microelectrodes under the application of static magnetic fields of two series of macrolactams containing in their structure 4,4'-bis(dimethylamino)biphenyl or 4,4'-dinitrobiphenyl groups in MeCN solution is described. The response of 4,4'-dinitrobiphenyl receptors is dominated by two successive one-electron reduction processes at -0.9 and -1.6 V versus AgCl/Ag. 4,4'-bis(dimethylamino)biphenyl-containing receptors display two one-electron oxidations above +0.8 and +1.0 V. In both cases, a dihedral/planar interconversion precedes the second electron transfer step. Upon application of moderate (0.05-0.2 T) static magnetic fields to the electrochemical cell, the rate of such dihedral/planar interconversion is lowered for both the reduction of 4,4'-dinitrobiphenyl receptors and the oxidation of 4,4'-bis(dimethylamino)biphenyl lactams. The electrochemical response of N-methylated receptors, for which different cisoid-cisoid, cisoid-transoid, and transoid-transoid forms exist, exhibits a significant peak splitting that can be associated to the presence of such conformational isomers. Application of magnetic fields produces a relative enhancement of some peaks that can be interpreted in terms of differential magnetoconvection involving such conformational isomers. (author)
17. Photo/electroluminescence properties of an europium (III) complex doped in 4,4'-N,N'-dicarbazole-biphenyl matrix
International Nuclear Information System (INIS)
Zhou Yonghui; Zhou Liang; Wu, Jing; Li, Hong-Yan; Zheng Youxuan; You Xiaozeng; Zhang Hongjie
2010-01-01
The photoluminescence properties of one europium complex Eu(TFNB) 3 Phen (TFNB = 4,4,4-trifluoro-1-(naphthyl)-1,3-butanedione, Phen = 1,10-phenanthroline) doped in a hole-transporting material CBP (4,4'-N,N'-dicarbazole-biphenyl) films were studied. A series of organic light-emitting devices (OLEDs) using Eu(TFNB) 3 Phen as the emitter were fabricated with a multilayer structure of indium tin oxide, 250 Ω/square)/TPD (N,N'-diphenyl-N,N'-bis(3-methyllphenyl)-(1,1'-biphenyl)-4,4'-diamine, 50 nm)/Eu(TFNB) 3 phen (x): CBP (4,4'-N,N'-dicarbazole-biphenyl, 45 nm)/BCP (2,9-dimethyl-4,7-diphenyl-l,10 phenanthroline, 20 nm)/AlQ (tris(8-hydroxy-quinoline) aluminium, 30 nm)/LiF (1 nm)/Al (100 nm), where x is the weight percentage of Eu(TFNB) 3 phen doped in the CBP matrix (1-6%). A red emission at 612 nm with a half bandwidth of 3 nm, characteristic of Eu(III) ion, was observed with all devices. The device with a 3% dopant concentration shows the maximum luminance up to 1169 cd/m 2 (18 V) and the device with a 5% dopant concentration exhibits a current efficiency of 4.46 cd/A and power efficiency of 2.03 lm/W. The mechanism of the electroluminescence was also discussed.
18. 8-{1-[(4′-Fluoro-[1,1′-biphenyl]-4-ylmethyl]piperidin-4-yl}-3,4-dihydroquinolin-2(1H-one chloroform 0.25-solvate
Directory of Open Access Journals (Sweden)
Nisar Ullah
2014-02-01
Full Text Available In the asymmetric unit of the title compound, C27H27FN2O·0.25CHCl3, there are two independent molecules (A and B together with a partially disordered chloroform molecule situated about an inversion center. The conformation of the two molecules is very similar. The bridging piperidine rings each have a chair conformation while the piperidin-2-one rings of the quinoline moiety have screw-boat conformations. The benzene rings of the biphenyl moiety are inclined to one another by 26.37 (4 and 23.75 (15° in molecules A and B, respectively. The mean plane of the central piperidine ring [r.m.s. deviation = 0.241 (2 Å in both molecules A and B] is inclined to the benzene ring of the quinoline moiety by 80.06 (4 in A and 83.75 (15° in B, while it is inclined to the adjacent benzene ring of the biphenyl group by 73.623 (15 in A and 75.65 (14° in B. In the crystal, individual molecules are linked by pairs of N—H...O hydrogen bonds, forming A–A and B–B inversion dimers with R22(8 ring motifs. The dimers are stabilized by C—H...O hydrogen bonds and linked via C—H...F and C—H...N hydrogen bonds into a three-dimensional network. Several C—H...π interactions are also present.
19. Conductivity and applications of Li-biphenyl-1,2-dimethoxyethane solution for lithium ion batteries
Institute of Scientific and Technical Information of China (English)
Geng Chu; Bo-Nan Liu; Fei Luo; Wen-Jun Li; Hao Lu; Li-Quan Chen; Hong Li
2017-01-01
The total conductivity of Li-biphenyl-l,2-dimethoxyethane solution (LixBp(DME)9.65,Bp =biphenyl,DME =1,2-dimethoxyethane,x =0.25,0.50,1.00,1.50,2.00) is measured by impedance spectroscopy at a temperature range from 0 ℃C to 40 ℃C.The Li1.50Bp(DME)9.65 has the highest total conductivity 10.7 mS/cm.The conductivity obeys Arrhenius law with the activation energy (Ea(x=0.50) =0.014 eV,Ea(x=1.00) =0.046 eV).The ionic conductivity and electronic conductivity of LixBp(DME)9.65 solutions are investigated at 20 ℃C using the isothermal transient ionic current (ITIC) technique with an ion-blocking stainless steal electrode.The ionic conductivity and electronic conductivity of Li1.00Bp(DME)9.65 are measured as 4.5 mS/cm and 6.6 mS/cm,respectively.The Li1.00Bp(DME)9.65 solution is tested as an anode material of half liquid lithium ion battery due to the coexistence of electronic conductivity and ionic conductivity.The lithium iron phosphate (LFP) and Li1.5Al0.5Ti1.5(PO4)3 (LATP) are chosen to be the counter electrode and electrolyte,respectively.The assembled cell is cycled in the voltage range of 2.2 V-3.75 V at a current density of 50 mA/g.The potential of Lit.00Bp(DME)9.65 solution is about 0.3 V vs.Li+/Li,which indicates the solution has a strong reducibility.The Li1.00Bp(DME)9.65 solution is also used to prelithiate the anode material with low first efficiency,such as hard carbon,soft carbon and silicon.
20. Isolation and characterisation of polychlorinated biphenyl (PCB degrading fungi from a historically contaminated soil
Directory of Open Access Journals (Sweden)
Di Toro Sara
2009-01-01
Full Text Available Abstract Background Polychlorinated biphenyls (PCBs are widespread toxic pollutants. Bioremediation might be an effective, cost competitive and environment-friendly solution for remediating environmental matrices contaminated by PCBs but it is still unsatisfactory, mostly for the limited biodegradation potential of bacteria involved in the processes. Very little is known about mitosporic fungi potential in PCB bioremediation and their occurrence in actual site historically contaminated soils. In the present study, we characterised the native mycoflora of an aged dump site soil contaminated by about 0.9 g kg-1 of Aroclor 1260 PCBs and its changing after aerobic biotreatment with a commercial complex source of bacteria and fungi. Fungi isolated from the soil resulting from 120 days of treatment were screened for their ability to adsorb or metabolise 3 target PCBs. Results The original contaminated soil contained low loads of few fungal species mostly belonging to the Scedosporium, Penicillium and Aspergillus genera. The fungal load and biodiversity generally decreased throughout the aerobic treatment. None of the 21 strains isolated from the treated soil were able to grow on biphenyl (200 mg L-1 or a mixture of 2-chlorobiphenyl, 4,4'-dichlorobiphenyl and 2,2',5,5'-tetrachlorobiphenyl (20 mg L-1 each as sole carbon sources. However, 16 of them grew in a mineral medium containing the same PCBs mixture and glucose (10 g L-1. Five of the 6 isolates, which displayed the faster and more extensive growth under the latter conditions, were found to degrade the 3 PCBs apparently without the involvement of ligninolytic enzymes; they were identified as Penicillium chrysogenum, Scedosporium apiospermum, Penicillium digitatum and Fusarium solani. They are the first PCB degrading strains of such species reported so far in the literature. Conclusion The native mycoflora of the actual site aged heavily contaminated soil was mainly constituted by genera often
1. Exposure to polychlorinated biphenyls and the thyroid gland – examining and discussing possible longitudinal health effects in humans
Energy Technology Data Exchange (ETDEWEB)
Gaum, Petra M., E-mail: pgaum@ukaachen.de [Institute for Occupational and Social Medicine, RWTH Aachen University, Pauwelsstraße 30, D-52074 Aachen (Germany); Lang, Jessica; Esser, André; Schettgen, Thomas [Institute for Occupational and Social Medicine, RWTH Aachen University, Pauwelsstraße 30, D-52074 Aachen (Germany); Neulen, Joseph [Clinic for Gynaecological Endocrinology and Reproductive Medicine, RWTH Aachen University, Pauwelsstraße 30, D-52074 Aachen (Germany); Kraus, Thomas; Gube, Monika [Institute for Occupational and Social Medicine, RWTH Aachen University, Pauwelsstraße 30, D-52074 Aachen (Germany)
2016-07-15
Background: Many previous studies have dealt with the effect of polychlorinated biphenyls (PCBs) on the thyroid gland, but their findings are inconsistent. One problem of these studies has been their use of cross-sectional designs. Objectives: The aim of the current study is to investigate longitudinal effects of PCBs on the thyroid gland, focusing on: morphological changes in thyroid tissue (i.e. thyroid volume), changes in thyroid hormones and in thyroid antibodies. Methods: A total of 122 individuals (M{sub age}=44.7) were examined over a period of four years (t{sup 1} until t{sup 4}). Medical history was collected via interviews, an ultrasound examination was performed and blood samples were taken to determine plasma PCB levels, thyroid stimulating hormone (TSH), free triiodthyronine (fT3), free thyroxine (fT4), thyroid peroxidase antibodies (TPOab), thyreoglobulin antibodies (TGab) and thyroid-stimulating hormone receptor antibodies (TSHRab). Rank correlation coefficients and mixed effect models were performed controlling for age and total lipids. Results: There were negative correlations between higher chlorinated biphenyls and fT3, cross-sectionally as well as longitudinally. We also found an interaction effect of higher-chlorinated PCBs over time for fT4 as well as TSHRab. In case of high exposure, a decrease in fT4 and an increase in TSHRab level were found over time. In regards to the other variables, our findings yielded no clear results in the examined time period. Conclusion: This is the first study to shows a PCB-related effect on fT3, fT4 and TSHRab over a four year period. The data also suggest that morphological and antibody findings remain inconsistent and do not allow for unambiguous interpretation. - Highlights: • This is a longitudinal study which includes data from four cross sections. • Higher-chlorinated biphenyls are negatively correlated with fT3. • There are interactions of time and higher-chlorinated biphenyls to TSHRab and fT4.
2. Biogenic volatile organic compounds - small is beautiful
Science.gov (United States)
Owen, S. M.; Asensio, D.; Li, Q.; Penuelas, J.
2012-12-01
While canopy and regional scale flux measurements of biogenic volatile organic compounds (bVOCs) are essential to obtain an integrated picture of total compound reaching the atmosphere, many fascinating and important emission details are waiting to be discovered at smaller scales, in different ecological and functional compartments. We concentrate on bVOCs below ground to plant species, and can be extracted from decaying litter. Naturally occurring monoterpenes in the rhizosphere provide a specialised carbon source for micro-organisms, helping to define the micro-organism community structure, and impacting on nutrient cycles which are partly controlled by microorganisms. Naturally occurring monoterpenes in the soil system could also affect the aboveground structure of ecosystems because of their role in plant defence strategies and as mediating chemicals in allelopathy. A gradient of monoterpene concentration was found in soil around Pinus sylvestris and Pinus halepensis, decreasing with distance from the tree. Some compounds (α-pinene, sabinene, humulene and caryophyllene) in mineral soil were linearly correlated with the total amount of each compound in the overlying litter, indicating that litter might be the dominant source of these compounds. However, α-pinene did not fall within the correlation, indicating a source other than litter, probably root exudates. We also show that rhizosphere bVOCs can be a carbon source for soil microbes. In a horizontal gradient from Populus tremula trees, microbes closest to the tree trunk were better enzymatically equipped to metabolise labeled monoterpene substrate. Monoterpenes can also increase the degradation rate in soil of the persistant organic pollutants, likely acting as analogues for the cometabo-lism of polychlorinated biphenyls (PCBs) Flowers of a ginger species (Alpinia kwangsiensis) and a fig species (Ficus hispida) showed different bVOC signals pre- and post pollination. For Ficus hispida, there are three
3. Source determination of highly chlorinated biphenyl isomers in pine needles - Comparison to several PCB preparations
International Nuclear Information System (INIS)
Wyrzykowska, Barbara; Bochentin, Ilona; Hanari, Nobuyasu; Orlikowska, Anna; Falandysz, Jerzy; Yuichi, Horii; Yamashita, Nobuyoshi
2006-01-01
The isomer specific composition of 13 technical PCB formulations of different origin and of pine needles was analyzed using GC/MS and HRGC/HRMS. Nonachlorinated biphenyls were identified in 11 among 13 formulations analyzed, with the highest abundance found for highly chlorinated ones (Aroclors 1268 and 1260, Chlorofen, Sovol, Kanechlors 600 and 500, Delor 106, Clophen A60). Decachlorobiphenyl was identified only in Aroclor 1268, Clophen A60, Aroclor 1260 and Chlorofen, comprising, respectively, 8.9, 2.8, 1.3 and 0.82% of the total bulk of nona- and decaCBs detected. Nona- and decaCB were detected in pine needles in Poland with the highest concentrations found at the sites neighboring to a former production sites of the Polish PCB formulations, while in pine needles collected around the Tokyo Bay nona- and decacCB were detected only in four of 10 sites and the concentrations corresponded to those found at the rural areas of Poland. - Pine needles were suitable as passive samplers for PCBs in air
4. Polychlorinated biphenyl concentrations in pooled serum from people in different age groups from five Chinese cities.
Science.gov (United States)
Wang, Qinghua; Yuan, Haodong; Jin, Jun; Li, Peng; Ma, Yulong; Wang, Ying
2018-05-01
Polychlorinated biphenyl (PCB) concentrations in human serum samples pooled by donor age and sex (≥60, 50-59, 40-49, 30-39, and 20-29 years old) were determined. The pooled samples were supplied by hospitals in five Chinese cities, which were Yitong (Jilin Province), Weifang (Shandong Province), Ganzi (Sichuan Province), Huaihua (Hunan Province), and Lingshui (Hainan Province). The total PCB concentrations were relatively low compared with concentrations that have been found in other parts of the world. Pentachlorobiphenyls were the dominant PCBs. The total PCB concentrations and the concentrations of most of the pentachlorobiphenyl congeners were slightly higher in the samples from younger donors than in the samples from older donors. The results indicated there is a new source of PCBs in China. Heptachlorobiphenyls in Lingshui may have been transported from Vietnam. Statistical analysis showed that young and old people had been exposed to different sources of PCBs. PCB 126 contributed more than the other dioxin-like PCBs to the total toxic equivalents when the samples were examined as a whole or by city, and the total toxic equivalents were higher in younger people than in older people for the whole sample set and for the Yitong samples. Copyright © 2018 Elsevier Ltd. All rights reserved.
5. Decomposition of polychlorinated biphenyls in soil with a dispersion mixture of metallic calcium and calcium oxide.
Science.gov (United States)
Mitoma, Yoshiharu; Mallampati, Srinivasa Reddy; Miyata, Hideaki; Kakeda, Mitsunori
2013-02-01
This study describes the decomposition of polychlorinated biphenyls (PCBs) in soil with dispersion mixtures of metallic calcium (Ca) and calcium oxide (CaO) at different temperatures. In these experiments, naturally moisturized and contaminated soil (1.0 g [31 ppm PCBs]), CaO (dried 2.0 wt%), and metallic Ca (0.01 g [0.25 mmol]) were introduced into a stainless steel pressure reactor under 0.1 MPa N(2) gas. The mixtures were stirred magnetically and heated at 260, 280, and 300 °C, respectively. Soil treatment with metallic Ca and CaO under various temperature conditions is extremely effective for degrading existing PCBs. Decomposition resulted from dechlorination (DC). Initial moisture in soil acted as a hydrogen source during stirring. Soil moisture can be beneficial for hydrodechlorination in the presence of metallic Ca and CaO. Furthermore, metallic Ca and CaO can greatly increase the number of collisions and mutual refinement. Treatment at 260, 280, and 300 °C combined with metallic Ca and CaO is effective for the decomposition (approximately 95 % DC) of PCBs in soil under natural moisture conditions.
6. Seasonal air-water exchange fluxes of polychlorinated biphenyls in the Hudson River Estuary
International Nuclear Information System (INIS)
Yan Shu; Rodenburg, Lisa A.; Dachs, Jordi; Eisenreich, Steven J.
2008-01-01
Polychlorinated biphenyls (PCBs) were measured in the air and water over the Hudson River Estuary during six intensive field campaigns from December 1999 to April 2001. Over-water gas-phase ΣPCB concentrations averaged 1100 pg/m 3 and varied with temperature. Dissolved-phase ΣPCB concentrations averaged 1100 pg/L and displayed no seasonal trend. Uncertainty analysis of the results suggests that PCBs with 5 or fewer chlorines exhibited net volatilization. The direction of net air/water exchange could not be determined for PCBs with 6 or more chlorines. Instantaneous net fluxes of ΣPCBs ranged from +0.2 to +630 ng m -2 d -1 . Annual fluxes of ΣPCBs were predicted from modeled gas-phase concentrations, measured dissolved-phase concentrations, daily surface water temperatures and wind speeds. The net volatilization flux was +62 μg m -2 yr -1 , corresponding to an annual loss of +28 kg/yr of ΣPCBs from the Hudson River Estuary for the year of 2000. - Investigation of the air-water exchange of PCBs in the Hudson River Estuary suggests that PCBs with 5 or fewer chlorines undergo net volatilization
7. Remediation of soils contaminated with polychlorinated biphenyls by microwave-irradiated manganese dioxide
International Nuclear Information System (INIS)
Huang Guanyi; Zhao Ling; Dong Yuanhua; Zhang Qin
2011-01-01
The removal of polychlorinated biphenyls (PCBs) using microwave-irradiated manganese dioxide (MnO 2 ) in PCB-contaminated soils under different conditions is investigated. The removal of PCB77 in two actual soil samples exhibits strong pH-dependent behavior, and the removal efficiency is higher in acidic soil (Ali-Perudic Ferrosols) than that in neutral soil (Udic Argosols). The removal kinetics of PCB77 using microwave-irradiated MnO 2 under different experimental conditions fits a pseudo-first-order kinetic model well. Both the removal efficiency and the kinetic constant (k) values of PCB77 in Ali-Perudic Ferrosols considerably increase, although in a nonlinear fashion, as the initial amount of MnO 2 is increased, as the treated soil mass is increased, and as the microwave power is increased. The reactivity of three PCBs (PCB28, PCB77, and PCB118) did not present as a function of the degree of chlorination in the reaction with microwave-irradiated MnO 2 . The pronounced removal of three PCBs in contaminated soil (all above 95%) indicates that MnO 2 in combination with microwave irradiation is promising for technological applications that seek to remediate sites critically polluted with PCBs.
8. Method and means for filtering polychlorinated biphenyls from a gas stream
International Nuclear Information System (INIS)
Sowinski, R.F.
1992-01-01
This patent describes a method of filtering, adjacent to an end user-customer's residence or business in which at least a single gas appliance is located, a natural gas stream in which polychlorinated biphenyls (PCB's) and degraded PCB products have been concentrated at sufficient levels to be a health threat in a natural gas gathering and distributing network. It comprises: introducing the natural gas stream to a filter selected from a group that includes impingement, absorbing and adsorbing media whereby PCB's and degraded PCB products concentrated in the gas stream at sufficient levels to be a health threat by a periodic loading of the natural gas within the gathering and distributing network, are filtered from the gas stream and captured irrespective of mode of transport, passing the filtered natural gas stream to the customer's gas appliance wherein safe use of the energy associated with the stream occurs; periodically and safely removing the filter, inserting a new filter in place of the removed filter
9. The uridine diphosphate glucuronosyltransferases: quantitative structure-activity relationships for hydroxyl polychlorinated biphenyl substrates
Energy Technology Data Exchange (ETDEWEB)
Wang, Degao [Dalian University of Technology, Department of Environmental Science and Technology, Dalian (China)
2005-10-01
Quantitative structure-activity relationships (QSARs), which relate the glucuronidation of hydroxyl polychlorinated biphenyls (OH-PCBs) - catalyzed by the uridine diphosphate glucuronosyltransferases (UGTs) - to their physicochemical properties and molecular structural parameters, can be used to predict the rate constants and interpret the mechanism of glucuronidation. In this study, QSARs have been developed that use 23 semi-empirical calculated quantum chemical descriptors to predict the logarithms of the constants 1/K{sub m} and V{sub max}, related to enzyme kinetics. A partial least squares regression method was used to select the optimal set of descriptors to minimize the multicollinearity between the descriptors, as well as to maximize the cross-validated coefficient (Q{sup 2} {sub cum}) values. The key descriptors affecting log(1/K{sub m}) were E{sub lumo}- E{sub homo} (the energy gap between the lowest unoccupied molecular orbital and the highest occupied molecular orbital) and q{sub C}{sup -} (the largest negative net atomic charge on a carbon atom), while the key descriptors affecting log V{sub max} were the polarizability {alpha}, the Connolly solvent-excluded volume (CSEV), and logP (the logarithm of the partition coefficient for octanol/water). From the results obtained it can be concluded that hydrophobic and electronic aspects of OH-PCBs are important in the glucuronidation of OH-PCBs. (orig.)
10. Persistent or not persistent? Polychlorinated biphenyls are readily depurated by grizzly bears (Ursus arctos horribilis).
Science.gov (United States)
Christensen, Jennie R; Letcher, Robert J; Ross, Peter S
2009-10-01
Major pharmacokinetic processes influencing polychlorinated biphenyl (PCB) accumulation in mammals include uptake, biotransformation, respiration, and excretion. We characterized some of the factors underlying PCB accumulation/loss by evaluating PCB concentrations and patterns in pre- and posthibernation grizzly bears (Ursus arctos horribilis) and their prey. The PCB congeners with vicinal meta- and para-chlorine unsubstituted hydrogen positions consistently showed loss both before and during hibernation, supporting the idea of a dominant role for biotransformation. Retention of all other studied congeners relative to that of PCB 194 varied widely (from bears do not eat or excrete. We estimate that grizzly bears retain less than 10% of total PCBs taken up from their diet. Our results suggest that for grizzly bears, depuration of PCBs via biotransformation is important (explaining approximately 40% of loss), but that nonbiotransformation processes, such as excretion, may be more important (explaining approximately 60% of loss). These findings, together with the approximately 91% loss of the persistent PCB 153 congener relative to PCB 194 in grizzly bears, raise important questions about how one defines persistence of PCBs in wildlife and may have bearing on the interpretation of food-web biomagnification studies.
11. Determination of non-ortho polychlorinated biphenyls in environmental Standard Reference Materials.
Science.gov (United States)
Brubaker, W W; Schantz, M M; Wise, S A
2000-07-01
The concentrations of three non-ortho ("coplanar") polychlorinated biphenyls, 3,3',4,4'-tetrachlorobiphenyl (IUPAC PCB 77), 3,3',4,4',5-pentachlorobiphenyl (IUPAC PCB 126), and 3,3',4,4',5,5'-hexachlorobiphenyl (IUPAC PCB 169), were determined in five NIST Standard Reference Materials (SRMs) of environmental and biological interest. The measured levels were approximately between (0.2 to 1.3) ng/g in SRM 1588a (Organics in Cod Liver Oil), (0.3 to 9) ng/g in SRM 1944 (New York/New Jersey Waterway Sediment), (0.2 to 0.4) ng/g in SRM 1945 (Organics in Whale Blubber), (1 to 18) ng/g in SRM 2974 (Organics in Freeze-dried Mussel Tissue [Mytilus edulis]), and (0.1 to 0.4) ng/g in candidate SRM 1946 (Lake Superior Fish Tissue). PCB 169 was present at < 0.1 ng/g in SRMs 1944 and 2974.
12. Forecasting long-range atmospheric transport episodes of polychlorinated biphenyls using FLEXPART
Science.gov (United States)
Halse, Anne Karine; Eckhardt, Sabine; Schlabach, Martin; Stohl, Andreas; Breivik, Knut
2013-06-01
The analysis of concentrations of persistent organic pollutants (POPs) in ambient air is costly and can only be done for a limited number of samples. It is thus beneficial to maximize the information content of the samples analyzed via a targeted observation strategy. Using polychlorinated biphenyls (PCBs) as an example, a forecasting system to predict and evaluate long-range atmospheric transport (LRAT) episodes of POPs at a remote site in southern Norway has been developed. The system uses the Lagrangian particle transport model FLEXPART, and can be used for triggering extra ("targeted") sampling when LRAT episodes are predicted to occur. The system was evaluated by comparing targeted samples collected over 12-25 h during individual LRAT episodes with monitoring samples regularly collected over one day per week throughout a year. Measured concentrations in all targeted samples were above the 75th percentile of the concentrations obtained from the regular monitoring program and included the highest measured values of all samples. This clearly demonstrates the success of the targeted sampling strategy.
13. Characteristics of trophic transfer of polychlorinated biphenyls in marine organisms in Incheon North Harbor, Korea.
Science.gov (United States)
Kim, Seung Kyu; Lee, Dong Soo; Oh, Jae Ryong
2002-04-01
The trophic transfer of polychlorinated biphenyls (PCBs) was characterized for zooplankton (primarily Paracalanus spp. and Acartia spp.), pacific oyster (Crassostrea gigas), shore crab (Hemigrapsus penicillatus), and goby (Acanthogobius hasta) in the aquatic system of Incheon North Harbor, Korea. The congener pattern in the species was clearly divided by the main PCB uptake route. Compared with zooplankton and oyster, the fraction of heavier homologues increased in crab and goby that take PCBs from food. Linear relationships were observed between log (fugacity in lipid/fugacity in seawater) and log Kow for all the species. For zooplankton and oyster, such an observation should not be regarded as a true absence of superhydrophobicity, because establishment of equilibrium with seawater was not evident. For crab and goby, the absence of superhydrophobicity was evidenced by the trophic transfer factor that continuously increased with Kow up to 10(7.8). These results suggest that superhydrophobicity might be species specific. The trophic transfer factors and the fugacity levels in the lipid phase indicated that bioaccumulation in crab and goby advanced beyond the level in equilibrium with seawater in the harbor basin.
14. An improved inventory of polychlorinated biphenyls in China: A case study on PCB-153
Science.gov (United States)
Xu, Yue; Tian, Chongguo; Wang, Xiaoping; Ma, Jianmin; Tang, Jianhui; Chen, Yingjun; Li, Jun; Zhang, Gan
2018-06-01
Emission inventory of pollutants is essential for the environmental fate study and management of the pollutant. To construct a reasonable PCB (polychlorinated biphenyls) inventory in China, this study estimates PCB usage and emission using power generating capacity, installed capacity of power plants and transformer substations, population density and GDP as surrogates. Inventory of representative PCB (PCB-153) with a resolution of 1/4° latitude × 1/4° longitude in China from 1952 to 2005 was generated and assessed as an example. Totally, about 20.3 kt PCBs were applied in China, of which 179 t were PCB-153. By the end of 2005, most of them (56.4%) were emitted into the soil, 2.7% entered the air, and about 20.8% was sealed in storage site or still in service. Historical emissions exhibited increasing trends after 1968, 1984 and 1994, which were mainly associated with usage or disposal processes. Although primary emission has been declined since 2005, the influence of secondary emission from soils, unintentionally produced PCBs (UP-PCB), and reemission from storage sites could be a long-lasting issue in the future. This new emission inventory improves previous PCB emission inventory significantly, which underestimated PCB emission in China considerably.
15. Polychlorinated biphenyl 126 stimulates basal and inducible aldosterone biosynthesis of human adrenocortical H295R cells
International Nuclear Information System (INIS)
Li, L.-A.; Wang, P.-W.; Chang, Louis W.
2004-01-01
To understand the effects of polychlorinated biphenyls (PCBs) on adrenal aldosterone biosynthesis, we have performed a systematical study to characterize the corresponding steroidogenic response of human adrenocortical cell line H295R to PCB126 exposure. We found that PCB126 at high concentrations stimulated basal and inducible aldosterone production. The aldosterone induction occurred concomitantly with activation of the CYP11B2 gene. Despite the fact that PCB126 acted in synergy with both potassium and angiotensin II (Ang II) in activation of aldosterone synthesis, PCB126 only modestly increased CYP11B2 mRNA expression in the presence of Ang II contrary to the synergistic transcriptional induction elicited by PCB126 and potassium. This implicated that PCB126 had differential interactions with the potassium and Ang II signaling systems in the regulation of aldosterone biosynthesis. In addition, high concentrations of PCB126 elevated transcriptional expression of the type I Ang II receptor (AT 1 ) and might thus sensitize the cellular Ang II responsiveness in both basal and inducible aldosterone biosynthesis. SF-1 was not involved in the PCB126-induced transcriptional regulation despite its importance in steroidogenic gene activation
16. Enantioseparation and identification for the rationalization of the environmental impact of 4 polychlorinated biphenyls.
Science.gov (United States)
Guo, Fangjie; Tang, Qiaozhi; Xie, Jingqian; Zhao, Lu; Liu, Kai; Liu, Weiping
2018-04-01
Polychlorinated biphenyls (PCBs) are harmful and persistent organic pollutants that have long been used in industrial manufacturing. Their persistence leads to accumulation in the food chain causing potential toxic effects. As 19 out of 78 of the chiral congeners have stable atropisomers at ambient temperature, we studied some typical enantiomers: PCB45, PCB95, PCB136, and PCB149. The chiral stationary phases OD-H and OJ-H were used for separation in analytic high-performance liquid chromatography (HPLC), as well as for collection in semi-preparative HPLC. The resolution was optimized with respect to n-hexane-based mobile phases, temperature, and flow rate. All pure enantiomers were recovered from semi-preparative HPLC within 15 minutes for practical purpose. Characterization of the absolute configurations were conducted with a combination of theoretical and experimental electronic circular dichroism measurements. The enantiomers of PCB45, PCB95, PCB136, and PCB149 proved to be eluted as R > S, S > R, R > S, and S > R, respectively. Molecular structures (eg, substituent groups) and properties (eg, bond lengths, bond angles, and dipole moments) were quantitatively analyzed to understand the toxicity effect of PCBs. In summary, we have developed a well-established methodology of collection and configuration identification for analogous PCB derivatives. © 2018 Wiley Periodicals, Inc.
17. Toxicological effects of polychlorinated biphenyls (PCBs) on freshwater turtles in the United States.
Science.gov (United States)
Ming-Ch'eng Adams, Clare Isabel; Baker, Joel E; Kjellerup, Birthe V
2016-07-01
Prediction of vertebrate health effects originating from persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) has remained a challenge for decades thus making the identification of bioindicators difficult. POPs are predominantly present in soil and sediment, where they adhere to particles due to their hydrophobic characteristics. Animals inhabiting soil and sediment can be exposed to PCBs via dermal exposure while others may obtain PCBs through contaminated trophic interaction. Freshwater turtles can serve as bioindicators due to their strong site fidelity, longevity and varied diet. Previous research observed the health effects of PCBs on turtles such as decreased bone mass, changed sexual development and decreased immune responses through studying both contaminated sites along with laboratory experimentation. Higher deformity rates in juveniles, increased mortality and slower growth have also been observed. Toxicological effects of PCBs vary between species of freshwater turtles and depend on the concertation and configuration of PCB congeners. Evaluation of ecotoxicological effects of PCBs in non-endangered turtles could provide important knowledge about the health effects of endangered turtle species thus inform the design of remediation strategies. In this review, the PCB presence in freshwater turtle habitats and the ecotoxicological effects were investigated with the aim of utilizing the health status to identify areas of focus for freshwater turtle conservation. Copyright © 2016 Elsevier Ltd. All rights reserved.
18. Non-dioxin like polychlorinated biphenyl indicator congeners in Northwest Atlantic spiny dogfish (Squalus acanthias).
Science.gov (United States)
St-Gelais, Adam T; Aeppli, Christoph; Burnell, Craig A; Costa-Pierce, Barry A
2017-07-15
In the Northwest Atlantic Ocean (NWAO), spiny dogfish (Squalus acanthias) is a promising commercial species following of collapse of traditional groundfish stocks. There are little available data assessing polychlorinated biphenyls (PCBs) in NWAO spiny dogfish. Here, six non-dioxin like PCB indicator congeners used in European Union regulations (EU NDL-PCB) were quantified via gas chromatography/mass spectrometry in 50 mature male spiny dogfish landed in southern New England. The average total concentration of EU NDL-PCBs was 58±43ng/g (mean±1 standard deviation). PCB values (corrected for co-elution) were below the 200ng/g EU regulatory limit. Results provide first recent regional insight into the PCB content of spiny dogfish in the NWAO. However, our study offers only a snapshot of one particular dogfish population, and might not be representative for the whole NWAO. This study underscores the need for further testing in this species. Copyright © 2017. Published by Elsevier Ltd.
19. Heavy metals and polychlorinated biphenyls (PCBs) sedimentation in the Lianhua Mountain Reservoir, Pearl River Delta, China.
Science.gov (United States)
Huang, Jingyu; Amuzu-Sefordzi, Basil; Li, Ming
2015-05-01
The Pearl River Delta is one of the biggest electronics manufacturing regions in the world. Due to the presence of abandoned industrial sites and the proliferation of large-scale electronics companies in the past four decades, it is therefore imperative to investigate the extent of heavy metals and polychlorinated biphenyls (PCBs) contamination in the region. Spatial and temporal distribution of heavy metals (Cr, Cu, Ni, Pb, and Zn) and PCBs (PCB28, PCB52, PCB101, PCB118, PCB138, PCB153, and PCB180) in the Lianhua Mountain reservoir in the Pearl River Delta, Dongguan City, China were examined based on a sedimentary profile analysis. Higher concentrations of the heavy metals detected were recorded in bottom sediments whereas 70% of the detected PCBs recorded maximum concentrations in top sediments. The geo-accumulation indices (Igeo) indicate that the study area is uncontaminated to moderately contaminated. Also, the integrated pollution indices (IPI) were above 1, except Pb, which shows that the study area is contaminated with heavy metals from anthropogenic sources. The concentrations of individual heavy metals and PCBs over a period of 60 years were also analyzed in order to establish a historical trend of pollution in the study area. This study provides baseline information on the level and historical trend of heavy metals and PCBs pollution in the study area.
20. Polychlorinated biphenyls in freshwater salmonids from the Kerguelen Islands in the Southern Ocean
Energy Technology Data Exchange (ETDEWEB)
Jaffal, A. [Laboratoire d' Eco-Toxicologie, EA 2069 Vignes et Vins de Champagne, Universite de Reims Champagne-Ardenne, F51687 Reims Cedex 2 (France); Givaudan, N. [UMR8079, CNRS, Orsay F-91405 (France); Univ Paris-Sud, Ecologie Systematique et Evolution, Orsay F-91405 (France); Betoulle, S. [Laboratoire d' Eco-Toxicologie, EA 2069 Vignes et Vins de Champagne, Universite de Reims Champagne-Ardenne, F51687 Reims Cedex 2 (France); Terreau, A. [IPEV Institut Polaire Francais, F29280 Plouzane (France); Paris-Palacios, S.; Biagianti-Risbourg, S. [Laboratoire d' Eco-Toxicologie, EA 2069 Vignes et Vins de Champagne, Universite de Reims Champagne-Ardenne, F51687 Reims Cedex 2 (France); Beall, E. [ECOBIOP, UMR 1224 INRA-Universite de Pau-Pays de l' Adour F63310 St-Pee-sur-Nivelle (France); Roche, H., E-mail: helene.roche@u-psud.fr [UMR8079, CNRS, Orsay F-91405 (France); Univ Paris-Sud, Ecologie Systematique et Evolution, Orsay F-91405 (France)
2011-05-15
The Subantarctic Kerguelen Islands (49{sup o}S, 70{sup o}E) contain freshwater ecosystems among the most isolated in the world. Concentrations of polychlorinated biphenyls (PCBs) were assessed in the muscle of 48 brook trout and 38 brown trout caught during summer and spring 2006 in the rivers, lakes and ponds of Kerguelen. The sum of 29 PCBs averaged 404 and 358 ng g{sup -1} lipid, and dioxin-like PCB was 19 and 69 ng g{sup -1} lipid, in brook and brown trout, respectively. The values showed a high variability and some fish accumulated PCBs at levels similar to those of fish from impacted areas. While inter-sex differences were limited, the season and the morphotype appeared to have the most influence. Fish captured in summer had muscle PCB concentrations about three times higher than those caught in spring and the 'river' morphotype of brook trout showed the highest PCB levels. - Highlights: > First assessment of PCB contamination of biota in Kerguelen Islands, Sub-Antarctica. > PCB bioaccumulation level in trout varies from very high to undetectable. > Habitat and morphotype are the most influential factors on the variability. > Distribution pattern of PCBs in the muscle of fish is morphotype dependent. - Salmonids in hydrosystems of the Kerguelen Islands (Southern Ocean) show a high PCB bioaccumulation.
1. Polycyclic aromatic hydrocarbon metabolism in mullets, Chelon labrosus, treated by polychlorinated biphenyls
International Nuclear Information System (INIS)
Narbonne, J.F.; Suteau, P.; Daubeze, M.; Audy, C.
1987-01-01
Contamination of the ocean by hydrocarbons has become a major environmental problem. Consequently, it is not surprising that residues of potentially toxic xenobiotics, such as benzo(a)pyrene (B(a)P), are present in marine species used as human food. The oxidative metabolism of aromatic hydrocarbons proceeds via intermediate arene oxides. Some of these metabolites are very reactive electrophiles and may interact with cellular macromolecules such as proteins, DNA and RNA. Thus, the ability of an organism to further metabolize arene oxides can be an important protective mechanism against the possible toxic effect of these molecules. The existence of hepatic cytochrome P-450 dependent monooxygenase activities in fish is now well established. The exposure of fish to polychlorinated biphenyls (PCB) increases both the monooxygenase activities and the total amount of cytochrome P-450 in the microsomal fractions of fish liver. The purpose of this study was to compare the toxication-detoxication balance in both control and PCB induced estuarine fish (Grey mullets)
2. Sex difference in polychlorinated biphenyl concentrations of burbot Lota lota from Lake Erie
Science.gov (United States)
Madenjian, C.P.; Stapanian, M.A.; Rediske, R.R.; O’Keefe, J. P.
2013-01-01
Whole-fish polychlorinated biphenyl (PCB) concentrations were determined for 25 female and 25 male burbot Lota lota from Lake Erie. Bioenergetics modeling was used to investigate whether the sex difference in growth rate resulted in a difference in gross growth efficiency (GGE) between the sexes. For ages 6–13 years, male burbot averaged 28 % greater PCB concentrations than female burbot. The sex difference in PCB concentrations widened for ages 14–17 years, with male burbot having, on average, 71 % greater PCB concentrations than female burbot. Bioenergetics modeling results showed that the faster growth rate exhibited by female burbot did not lead to greater GGE in female individuals of the younger burbot and that the faster growth by female fish led to female GGE being only 2 % greater than male GGE in older burbot. Although our bioenergetics modeling could not explain the observed sex difference in PCB concentrations, we concluded that a sex difference in GGE was the most plausible explanation for the sex difference in PCB concentrations of burbot ages 6–13 years. Not only are male fish likely to be more active than female fish, but the resting metabolic rate of male fish may be greater than that of female fish. We also concluded that the widening of the sex difference in PCB concentrations for the older burbot may be due to many of the older male burbot spending a substantial amount of time in the vicinity of mouths of rivers contaminated with PCBs.
3. Oxidation of dibenzothiophene (DBT by Serratia marcescens UCP 1549 formed biphenyl as final product
Directory of Open Access Journals (Sweden)
de Araújo Hélvia W
2012-05-01
Full Text Available Abstract Background The desulphurization of dibenzothiophene (DBT, a recalcitrant thiophenic fossil fuel component by Serratia marcescens (UCP 1549 in order for reducing the Sulphur content was investigated. The Study was carried out establishing the growth profile using Luria Bertani medium to different concentrations of DBT during 120 hours at 28°C, and orbital Shaker at 150 rpm. Results The results indicated that concentrations of DBT 0.5, 1.0 and 2.0 mM do not affected the growth of the bacterium. The DBT showed similar Minimum Inhibitory Concentration (MIC and Minimum Bactericidal Concentration (MCB (3.68 mM. The desulphurization of DBT by S. marcescens was used with 96 hours of growth on 2 mM of DBT, and was determined by gas chromatography (GC and GC-mass spectrometry. In order to study the desulphurization process by S. marcescens was observed the presence of a sulfur-free product at 16 hours of cultivation. Conclusions The data suggests the use of metabolic pathway “4S” by S. marcescens (UCP 1549 and formed biphenyl. The microbial desulphurization process by Serratia can be suggest significant reducing sulphur content in DBT, and showed promising potential for reduction of the sulfur content in diesel oil.
4. Distribution of polychlorinated biphenyls in the Housatonic River and adjacent aquifer, Massachusetts
Science.gov (United States)
Gay, Frederick B.; Frimpter, Michael H.
1985-01-01
Polychlorinated biphenyls (PCB's) are sorbed to the fine-grained stream-bottom sediments along the Housatonic River from Pittsfield, Massachusetts, southward to the Massachusetts-Connecticut boundary. The highest PCB concentrations, up to 140,000 micrograms per kilogram, were found in samples of bottom material from a reach of the river between Pittsfield and Woods Pond Dam in Lee, Massachusetts. Sediments in Woods Pond have been estimated to contain about 11,000 pounds of PCB's. Approximately 490 pounds per year of PCB's have also been estimated to move past the Housatonic River gaging station at Great Barrington. The distribution of hydraulic heads, water temperatures, and concentrations of dissolved oxygen, ammonia, nitrate, iron, and manganese in ground water shows that industrial water-supply wells in a sand and gravel aquifer adjacent to a stretch of the river called Woods Pond have been inducing ground-water recharge through the PCB-contaminated bottom sediments of the pond since late 1956. These data indicate that, at one location along the shore of the pond, the upper 40 feet of the aquifer contains water derived from induced infiltration. However, this induced recharge has not moved PCB's from the bottom sediments into a vertical section of the aquifer located 5 feet downgradient from the edge of Woods Pond. Samples taken at selected intervals in this section showed that no PCB's sorbed to the aquifer material or dissolved in the ground water within the detection limits of the chemical analyses.
5. Importance of growth rate on mercury and polychlorinated biphenyl bioaccumulation in fish
Science.gov (United States)
Li, Jiajia; Haffner, G. Douglas; Patterson, Gordon; Walters, David M.; Burtnyk, Michael D.; Drouillard, Ken G.
2018-01-01
To evaluate the effect of fish growth on mercury (Hg) and polychlorinated biphenyl (PCB) bioaccumulation, a non–steady‐state toxicokinetic model, combined with a Wisconsin bioenergetics model, was developed to simulate Hg and PCB bioaccumulation in bluegill (Lepomis macrochirus). The model was validated by comparing observed with predicted Hg and PCB 180 concentrations across 5 age classes from 5 different waterbodies across North America. The non–steady‐state model generated accurate predictions for Hg and PCB bioaccumulation in 3 of 5 waterbodies: Apsey Lake (ON, Canada), Sharbot Lake (ON, Canada), and Stonelick Lake (OH, USA). The poor performance of the model for the Detroit River (MI, USA/ON, Canada) and Lake Hartwell (GA/SC, USA), which are 2 well‐known contaminated sites with possibly high heterogeneity in spatial contamination, was attributed to changes in feeding behavior and/or prey contamination. Model simulations indicate that growth dilution is a major component of contaminant bioaccumulation patterns in fish, especially during early life stages, and was predicted to be more important for hydrophobic PCBs than for Hg. Simulations that considered tissue‐specific growth provided some improvement in model performance particularly for PCBs in fish populations that exhibited changes in their whole‐body lipid content with age. Higher variation in lipid growth compared with that of lean dry protein was also observed between different bluegill populations, which partially explains the greater variation in PCB bioaccumulation slopes compared with Hg across sampling sites.
6. Atmospheric occurrence, transport and gas-particle partitioning of polychlorinated biphenyls over the northwestern Pacific Ocean
Science.gov (United States)
Wu, Zilan; Lin, Tian; Li, Zhongxia; Li, Yuanyuan; Guo, Tianfeng; Guo, Zhigang
2017-10-01
Ship-board air samples were collected during March to May 2015 from the East China Sea (ECS) to the northwestern Pacific Ocean (NWP) to explore the atmospheric occurrence and gas-particle partitioning of polychlorinated biphenyls (PCBs) when the westerly East Asian Monsoon prevailed. Total PCB concentrations in the atmosphere ranged from 56.8 to 261 pg m-3. Higher PCB levels were observed off the coast and minor temperature-induced changes showed that continuous emissions from East Asia remain as an important source to the regional atmosphere. A significant relationship between Koa (octanol-air partition coefficient) and KP (gas-particle partition coefficient) for PCBs was observed under continental air masses, suggesting that land-derived organic aerosols affected the PCB gas-particle partitioning after long-range transport, while an absence of this correlation was identified in marine air masses. The PCB partitioning cannot be fully explained by the absorptive mechanism as the predicted KP were found to be 2-3 orders of magnitude lower than the measured Kp, while the prediction was closely matched when soot adsorption was considered. The results suggested the importance of soot carbon as a transport medium for PCBs during their long-range transport and considerable impacts of continental outflows on PCBs across the downwind area. The estimated transport mass of particulate PCBs into the ECS and NWP totals 2333 kg during the spring, constituting ca. 17% of annual emission inventories of unintentionally produced PCB in China.
7. Dioxin-like polychlorinated biphenyls in marine fish from Shandong, China, and human dietary exposure.
Science.gov (United States)
Cao, Yanping; Jiang, Dafeng; Li, Fenghua; Chen, Jindong; Li, Wei; Jiao, Yanni; Li, Lu
2018-05-22
The occurrence and human dietary exposure of 12 dioxin-like polychlorinated biphenyls (DL-PCBs) in 41 marine fish samples from Shandong Province of China were investigated. The DL-PCB congeners were extracted using automated Soxhlet extraction, purified via a composite column cleanup procedure and analyzed by gas chromatography-triple quadrupole mass spectrometry. DL-PCB congeners were found in all analyzed samples, with a mean concentration of 0.887 ng/g ww (wet weight). The TEQ concentrations of DL-PCBs in individual fish samples ranged from 0.011 to 9.214 pg WHO TEQ/g ww. The mean dietary intake for all fish species was 36.5 pg TEQ/kg bw/month, which was lower than the provisional tolerable monthly intake of 70 pg TEQ/kg bw/month set by the Joint FAO/WHO Expert Committee on Food Additives. To monitor the trend of DL-PCBs in fish for food safety control it is necessary to maintain a surveillance program.
8. A review of the neurotoxicity of non-dioxin-like polychlorinated biphenyls
Energy Technology Data Exchange (ETDEWEB)
Seegal, R. [Albany Univ., NY (United States). Wadsworth Center, New York State Dept. of Health and School of Public Health
2004-09-15
It is perhaps both presumptuous and somewhat nostalgic for me to present research findings from both myself and others describing the changes in central nervous system (CNS) function that occur following exposure to non-dioxin-like polychlorinated biphenyls (PCBs) at the 2004 Dioxin meeting. Presumptuous because my presentation occurs during this meeting where the majority of the research is concerned with the consequences of exposure to dioxins (the most toxic substance produced by man) and nostalgic because, in 1992, I presented some of my earliest work demonstrating that non-dioxin-like PCBs were capable of significantly altering neurochemical function. Much has changed in the intervening twelve years. Laboratories in the United States and Europe now routinely study and describe the neurotoxicological effects of developmental and in vitro exposure to non-dioxin-like PCBs. My task will be to briefly describe the highlights of that research and suggest additional approaches that will hopefully increase our ability to understand the mechanisms of action of non-dioxin-like PCBs on neuronal and behavioral function in populations of exposed humans.
9. Organochlorine pesticides and polychlorinated biphenyls in herring from the southern Baltic, 1983
Energy Technology Data Exchange (ETDEWEB)
Falandysz, J
1986-02-01
Hexachlorobenzene (HCB), alpha-, beta-, gamma- and delta-benzenehexachloride (BHC, HCH), p,p'-DDE, o,p'-DDD, o,p'-DDT, p,p'-DDD and p,p'-DDT (sigma DDT) and polychlorinated biphenyls (PCB) levels have been determined in muscle tissue of 187 herring (Clupea harengus) netted during 1983 in a different regions in the southern part of the Baltic Sea. The mean levels found for herring muscle tissue related to wet weight (microgram/kg) were: 14 HCB, 18 alpha-BHC, 23 beta-BHC, 14 gamma-BHC, delta-BHC remained undetected, 56 sigma BHC, 115 p,p'-DDE, o,p'-DDD and o,p'-DDT remained undetected, 84 p,p'-DDD, 51 p,p'-DDT, 250 sigma DDT and 530 PCB. The levels of organochlorine pesticides determined in wet muscles or extractable lipids of herring are nearly 2-3 times as high as those noted in fish sampled in the same area in two years before, while for PCBs the wet weight levels were comparable, and when based on a lipid weight are somewhat higher. The results are compared with levels found in herring collected in different regions of the Baltic Sea during 1965-1983, and reported previously by other authors.
10. Polychlorinated Biphenyls Induce Mitochondrial Dysfunction in SH-SY5Y Neuroblastoma Cells.
Directory of Open Access Journals (Sweden)
Stefania Cocco
Full Text Available Chronic exposure to polychlorinated biphenyls (PCBs, ubiquitous environmental contaminants, can adversely affect the development and function of the nervous system. Here we evaluated the effect of PCB exposure on mitochondrial function using the PCB mixture Aroclor-1254 (A1254 in SH-SY5Y neuroblastoma cells. A 6-hour exposure to A1254 (5 μg/ml reduced cellular ATP production by 45%±7, and mitochondrial membrane potential, detected by TMRE, by 49%±7. Consistently, A1254 significantly decreased oxidative phosphorylation and aerobic glycolysis measured by extracellular flux analyzer. Furthermore, the activity of mitochondrial protein complexes I, II, and IV, but not V (ATPase, measured by BN-PAGE technique, was significantly reduced after 6-hour exposure to A1254. The addition of pyruvic acid during exposure to A1254 significantly prevent A1254-induced cell injury, restoring resting mitochondrial membrane potential, ATP levels, oxidative phosphorylation and aerobic glycolysis. Furthermore, pyruvic acid significantly preserved the activity of mitochondrial complexes I, II and IV and increased basal activity of complex V. Collectively, the present results indicate that the neurotoxicity of A1254 depends on the impairment of oxidative phosphorylation, aerobic glycolysis, and mitochondrial complexes I, II, and IV activity and it was counteracted by pyruvic acid.
11. Indicator polychlorinated biphenyl residues in muscle tissue of fish from Black Sea coast of Bulgaria
Directory of Open Access Journals (Sweden)
S. Georgieva
2016-06-01
Full Text Available Abstract. Polychlorinated biphenyls (PCBs are characterized by high lipophilicity and persistence in the environment and will therefore bioaccumulate and biomagnify in the food chain. PCBs were determined in muscle tissue of four fish species: goby (Neogobius melanostomus, horse mackerel (Trachurus Mediterraneus ponticus, shad (Alosa pontica pontica and turbot (Psetta maxima maeotica. Samples were collected from Bulgarian Black Sea coast during 2007 – 2011. The PCBs were analyzed in order to examine the time trends of PCB concentrations in fish from Black Sea. The six individual PCBs congeners were determined by capillary gas chromatography system with mass spectrometry detection. PCBs were found in all fish species at concentrations ranging between 2.32 ng/g ww (wet weight and 32.87 ng/g ww in goby and shad, respectively. PCB profiles have been found to be similar in all the fish species tested. The most abundant PCB congeners in fish species were hexa- and heptachlorinated PCBs 138, 153 and 180. PCB 153 was the dominant congener in all fish studied and were found in the range from 0.95 ng/g ww (horse mackerel 2011 to 11.67 ng/g ww (shad 2010. The sum of six indicator PCBs in all fish species did not exceed the European maximum limit of 75 ng/g ww. The levels of PCBs in fish from Bulgarian Black Sea coast were found lower than in fish species from other seas – the Aegean Sea and the Mediterranean Sea.
12. Occupational exposure to polychlorinated biphenyls and risk of cutaneous melanoma: a meta-analysis.
Science.gov (United States)
Boffetta, Paolo; Catalani, Simona; Tomasi, Cesare; Pira, Enrico; Apostoli, Pietro
2018-01-01
The aim of this study was to carry out a meta-analysis of studies on exposure to polychlorinated biphenyls (PCBs) and the risk of malignant melanoma (MM). We searched Scopus, PubMed, and reference lists; among 807 potentially relevant articles, we selected those based on 12 populations. Data were extracted according to a standardized form; the Newcastle-Ottawa Scale was used to assess study quality. Meta-analyses were carried out according to fixed-effect and random-effects models. The fixed-effect summary relative risk (RR) for MM was 0.91 [95% confidence interval (CI): 0.82-1.00]; the random-effects summary RR was 1.05 (95% CI: 0.78-1.32). The random-effects summary RR from eight occupational cohorts was 1.13 (95% CI: 0.91-1.35) and that from four community-based studies was 0.84 (95% CI: 0.36-1.31). The quality of the studies and the methods for PCB exposure assessment did not influence the RR. These results do not support the hypothesis of an association between PCB exposure and the risk of MM.
13. Contamination by polychlorinated biphenyls (PCBs) in striped dolphins (Stenella coeruleoalba) from the Southeastern Mediterranean Sea.
Science.gov (United States)
Storelli, Maria Maddalena; Barone, Grazia; Giacominelli-Stuffler, Roberto; Marcotrigiano, Giuseppe Onofrio
2012-09-01
Concentrations of polychlorinated biphenyls (PCBs) including dioxin-like PCBs (non-ortho, PCB 77, PCB 126, and PCB 169 and mono-ortho, PCB 105, PCB 118, and PCB 156) were measured in different organs and tissues (melon, blubber, liver, kidney, lung, heart, and muscle tissue) of striped dolphins (Stenella coeruleoalba) from the Eastern Mediterranean Sea (Adriatic Sea). The mean highest levels were in blubber and melon, followed by liver, kidney, lung, heart, and muscle tissue. PCB profiles were similar in all tissues and organs being dominated by the higher chlorinated homologues (hexa-CBs, 55.8-62.1%; penta-CBs, 15.4-20.0%; and hepta-CB PCB 180, 12.7-16.5%). Major PCBs in all tissues were congeners 138 and 153 collectively accounting for 50.6-58.3% of the total PCB concentrations, followed by PCB 101, 105, 118, and 180 constituting from 27.0% to 31.0%. PCB levels were higher in adult males than in adult females. The estimated 2,3,7,8-TCDD toxic equivalents of non- and mono-ortho PCBs were much higher than the threshold level above which adverse effects have been observed in other marine mammals species, suggesting that striped dolphins in this region are at risk for toxic effects.
14. Gas chromatography/multiphoton ionization/time-of-flight mass spectrometry of polychlorinated biphenyls
International Nuclear Information System (INIS)
Matsui, Taiki; Uchimura, Tomohiro; Imasaka, Totaro
2011-01-01
A sample mixture of polychlorinated biphenyls (PCBs) was measured by gas chromatography/multiphoton ionization/time-of-flight mass spectrometry (GC/MPI/TOF-MS) using four types of laser sources. When a fourth harmonic emission (266 nm) of a picosecond Nd:YAG laser (1064 nm) was utilized, highly chlorinated PCBs larger than hepta-CBs were not observed. A fifth harmonic emission (213 nm) of the picosecond Nd:YAG laser allowed the measurement of PCBs from di-CBs to octa-CBs, and the limit of detection (LOD) was several pg for each component of PCBs. The LOD for the total amount of PCBs, which was calculated using the protocol provided by the Ministry of the Environment, Japan, was 1000 pg. The signal intensity of the congeners with chlorine atoms at the ortho positions (non-coplanar PCBs) was enhanced by using the fifth harmonic emission. When the fourth harmonic emission remaining after fifth harmonic generation was simultaneously used, the LOD for total PCBs was improved to 667 pg. The PCB sample was also measured using a third harmonic emission (267 nm) of a femtosecond Ti:sapphire laser (800 nm), providing an LOD of 677 pg. Thus, the two-color beam (266/213 nm) of a picosecond Nd:YAG laser had a comparable, or even slightly superior, performance to the more expensive femtosecond Ti:sapphire laser.
15. Polychlorinated biphenyl congener patterns in fish near the Hanford Site (Washington State, USA).
Science.gov (United States)
Rodenburg, Lisa A; Delistraty, Damon; Meng, Qingyu
2015-03-03
It is well-known that absorption, distribution, metabolism, and excretion (ADME) processes in fish can alter polychlorinated biphenyl (PCB) congener patterns in fish, but these patterns have never been investigated using an advanced source-apportionment tool. In this work, PCB congener patterns in freshwater fish were examined with positive matrix factorization (PMF). PCB congeners were quantified via EPA Method 1668 in fillet and carcass of six species in four study areas in the Columbia River near the Hanford Site. Six factors were resolved with PMF2 software. Depletion and enhancement of PCB congeners in factors, relative to Aroclor 1254, suggested biotransformation (via cytochrome P450) and bioaccumulation in fish, respectively. Notable differences were observed among species and across study locations. For example, sturgeon and whitefish exhibited congener patterns consistent with Aroclor weathering, suggesting potential PCB metabolism in these species. In terms of location, average concentration of total PCBs for all species combined was significantly higher (P < 0.05) at Hanford 100 and 300 areas, relative to upriver and downriver study sites. Furthermore, a distinct PCB signature in sturgeon and whitefish, collected at Hanford study areas, suggests that Hanford is a unique PCB source.
16. Effect of polychlorinated biphenyls on osmoregulatory response and apoptosis in GIFT tilapia, Oreochromis niloticus.
Science.gov (United States)
Zheng, Y; Qiu, L; Fan, L; Song, C; Meng, S; Chen, J
2016-09-02
In the present study, GIFT tilapia Oreochromis niloticus were exposed to polychlorinated biphenyls (PCBs) for 7, 14, and 21 days. Over the duration of the exposure, genotoxicity and the activity of Na + /K + -ATPase (NKA) and Ca + /Mg + -ATPase (CMA) were measured in the gill, kidney, and intestine, to evaluate changes in osmoregulatory response in O. niloticus. Our results showed significant decreases in organic NKA (except in gill tissues after 0.5 mg/L PCB-exposure) and CMA activity. The results of the genotoxicity assay showed significant increases in atp1a1a, nkcc2 (only in gill tissue), and fxyd7 (except after 21 days of 5 mg/L PCB exposure). We found significant increases in caspase proteins in the liver in the 5-mg/L PCB exposure group, and the transcripts showed dose-dependent increases between treatment groups over the exposure duration. This study presents evidence that chronic exposure to PCB could result in organic osmoregulatory response and hepatic apoptosis in GIFT tilapia.
17. Concentrations and Toxic Equivalency of Polychlorinated Biphenyls in Polish Wastewater Treatment Plant Effluents.
Science.gov (United States)
Urbaniak, Magdalena; Kiedrzyńska, Edyta
2015-10-01
Wastewater treatment plants (WWTPs) are widely recognized as important sources of toxic contaminants such as polychlorinated biphenyls (PCBs). An example is given in the present paper, where concentrations of 12 dioxin-like PCBs (dl-PCBs) congeners were investigated in effluents from 14 WWTPs of different sizes, using gas chromatography tandem-mass spectrometry. The results obtained demonstrate that the smallest WWTPs are characterized by the highest total dl-PCB concentration of 102.69 pg/L, roughly twice those of medium-size and large WWTPs, i.e. 41.14 and 48.29 pg/L, respectively. In all cases, the concentrations obtained were generated mostly by increased contributions of PCB-77, PCB-105 and PCB-118 which constituted 48 %-59 % of the mean dl-PCB concentration. The results also reveal a predominance of mono-ortho over non-ortho PCBs. All three types of WWTP effluent were found to have similar toxic equivalency (TEQ) values, ranging from 0.31 for large to 0.37 pg TEQ/L for medium WWTPs.
18. Polychlorinated biphenyls and polybrominated diphenyl ethers in the North American atmosphere
International Nuclear Information System (INIS)
Shen Li; Wania, Frank; Lei, Ying D.; Teixeira, Camilla; Muir, Derek C.G.; Xiao, Hang
2006-01-01
To assess the spatial concentration variability of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in the atmosphere on a large continental scale, their annually integrated air concentrations were determined in 2000/2001 using XAD-based passive air samplers (PAS). The network included 40 stations in Canada, the United States, Mexico, Belize and Costa Rica, and covered 72 degrees of latitude and longitude. Total concentrations of PCB and PBDE congeners ranged from below the detection limit to 130 ng PAS -1 and 24 ng PAS -1 , respectively. PCBs displayed a large variation between urban, rural and remote sites, whereas PBDEs did not follow such a pattern. Open burning of 'Penta'-containing waste may have contributed to the PBDEs detected in the air samples from rural and remote areas. Air from the Canadian Arctic had a relatively higher percentage of lighter PCB congeners than air sampled in the tropical region, which is interpreted as evidence for global fractionation. - A continental passive air sampling network reveals atmospheric distribution patterns of two classes of industrial chemicals
19. Placental markers of human exposure to polychlorinated biphenyls and polychlorinated dibenzofurans
International Nuclear Information System (INIS)
Lucier, G.W.; Nelson, K.G.; Everson, R.B.; Wong, T.K.; Philpot, R.M.; Tiernan, T.; Taylor, M.; Sunahara, G.I.
1987-01-01
These studies have evaluated biochemical changes in placentae from humans exposed to rice oil contaminated with polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs) in Taiwan. Placentae were obtained from nonsmoking women 4 to 5 years after the exposure had occurred. The exposed individuals ingested approximately 1 to 3 g PCBs and 5 mg PCDFs, and many exhibited symptoms characteristic of PCB poisoning. This disease was termed Yu-Cheng in Chinese. Based on data from experimental animals models, the authors examined a number of parameters in placentae from control and exposed women, including arylhydrocarbon hydroxylase (AHH) activity, cytochrome P-450 isozymes, epidermal growth factor (EGF) receptor binding properties and actions, and Ah receptor. They also quantified concentrations of various PCB and PCDF congeners known to be present in the contaminated rice oil. The results revealed a dramatic elevation in placental AHH activity in samples from PCB/PCDF-exposed women. This increase in enzyme activity was associated with a parallel increase in placental microsomal protein immunochemically related to cytochrome P-450 form 6. EGF receptor-mediated autophosphorylation capacity was significantly diminished in PCB/PCDF placentae, but this effect was not associated with changes in plasma membrane EGF receptor binding properties. Two PCDF congeners were detected in Yu-Cheng placentae but not controls. Several PCBs were also detected in much higher concentrations in Yu-Cheng placentae. Surprisingly, placental concentrations of PCBs correlated better with effects than did the PCDFs. The findings are discussed in relation to the risk assessment process
20. Importance of passive diffusion in the uptake of polychlorinated biphenyls by phagotrophic protozoa
Energy Technology Data Exchange (ETDEWEB)
Kujawinski, E.B.; Farrington, J.W.; Moffett, J.W.
2000-05-01
Unicellular protozoan grazers represent a size class of organisms where a transition in the mechanism of chlorobiphenyl (CB) introduction, from diffusion through surface membranes to ingestion of contaminated prey, could occur. This study compares the relative importance of these two processes in the overall uptake of polychlorinated biphenyls by protists. Uptake rates and steady-state concentrations were compared in laboratory cultures of grazing and nongrazing protozoa. These experiments were conducted with a 10-{micro}m marine scuticociliate (Uronema sp.), bacterial prey (Halomonas halodurans), and a suite of 21 CB congeners spanning a range of aqueous solubilities. The dominant pathway of CB uptake by both grazing and nongrazing protozoa was diffusion. Organic-carbon-normalized CB concentrations (in the protozoan cell) were equivalent in grazing and nongrazing protozoa for all congeners studied. Rate constants for uptake into and loss from the protozoan cell were independently determined by using [3,3{prime}, 4,4{prime}-{sup 14}C]tetrachlorobiphenyl (IUPAC no. 77), 0.38 {+-} 0.03 min{sup {minus}1} and (1.1 {+-} 0.1) x 10{sup {minus}5} (g of organic carbon){minus}{sup {minus}1} min{sup {minus}1}, respectively. Magnitudes of the uptake and loss processes were calculated and compared by using a numerical model. The model result was consistent with data from the bioaccumulation experiment and supported the hypothesis that diffusive uptake is faster than ingestive uptake in phagotrophic unicellular protozoa.
1. Age-related polychlorinated biphenyl dynamics in immature bull sharks (Carcharhinus leucas).
Science.gov (United States)
Olin, Jill A; Beaudry, Marina; Fisk, Aaron T; Paterson, Gordon
2014-01-01
Polychlorinated biphenyls (PCBs) were quantified in liver tissues of bull sharks (Carcharhinus leucas) ranging in age from 3 yr. Summed values of PCBs (ΣPCBs) ranged from 310 ng/g to 22 070 ng/g (lipid wt) across age classes with ΣPCB concentrations for the youngest sharks in the present study (3-yr-old sharks, highlighting the extent of exposure of this young life stage to this class of persistent organic pollutants (POPs). Age normalization of PCB congener concentrations to those measured for the youngest sharks demonstrated a significant hydrophobicity (log octanol/water partition coefficient [KOW ]) effect that was indicative of maternal offloading of highly hydrophobic (log KOW ≥6.5) congeners to the youngest individuals. A distinct shift in the PCB congener profiles was also observed as these young sharks grew in size. This shift was consistent with a transition from the maternally offloaded signal to the initiation of exogenous feeding and the contributions of mechanisms including growth dilution and whole-body elimination. These results add to the growing pool of literature documenting substantially high concentrations of POPs in juvenile sharks that are most likely attributable to maternal offloading. Collectively, such results underscore the potential vulnerability of young sharks to POP exposure and pose additional concerns for shark-conservation efforts. © 2013 SETAC.
2. Presence of polychlorinated biphenyls (PCBs) in bottled drinking water in Mexico City.
Science.gov (United States)
Salinas, Rutilio Ortiz; Bermudez, Beatriz Schettino; Tolentino, Rey Gutiérrez; Gonzalez, Gilberto Díaz; Vega y León, Salvador
2010-10-01
This paper describes the concentrations of seven polychlorinated biphenyls (PCBs) in bottled drinking water samples that were collected over 1 year from Mexico City in two sizes (1.5 and 19 L), using gas chromatography with an electron capture detector. PCBs 28 (0.018-0.042 μg/L), 52 (0.006-0.015 μg/L) and 101 (0.001-0.039 μg/L) were the most commonly found and were present in the majority of the samples. However, total concentrations of PCBs in bottled drinking water (0.035-0.039 μg/L) were below the maximum permissible level of 0.50 μg/L stated in Mexican regulations and probably do not represent a hazard to human health. PCBs were detectable in all samples and we recommend a monitoring program be established to better understand the quality of drinking bottled water over time; this may help in producing solutions for reducing the presence of organic contaminants.
3. Detailed analysis of polybrominated biphenyl congeners in bird eggs from Norway
International Nuclear Information System (INIS)
Vetter, Walter; Recke, Roland von der; Herzke, Dorte; Nygard, Torgeir
2008-01-01
Individual eggs of six species of birds from Norway representing different food chains were analysed for residues of polybrominated biphenyls (PBBs). In all species, the residue pattern was dominated by hexaBBs. The dominating congeners were PBB 153, PBB 154, and PBB 155. Whereas PBB 153 is present in technical hexabromobiphenyl, PBB 154 and PBB 155 are formed by the reductive debromination of decabromobiphenyl. This was evidenced by the detection of several heptaBBs and octaBBs all of which are typical degradation intermediates of PBB 209. Hepta- and octaBBs were more than one order of magnitude less abundant than the hexaBBs. The second most prevailing homologue group was pentaBBs. The most relevant pentabrominated isomers were PBB 99 and PBB 101. Concentrations of the three hexaBBs - PBB 153, PBB 154, and PBB 155 - amounted to 1.3-13 ng/g wet weight or 3-23% of the contamination with polybrominated diphenyl ethers. - We provide for the first time detailed information on the PBB congeners present in eggs of bird of prey, and quantified three hexabromo congeners
4. Uptake of polychlorinated biphenyls and organochlorine pesticides from soil and air into radishes (Raphanus sativus)
Energy Technology Data Exchange (ETDEWEB)
Mikes, Ondrej; Cupr, Pavel [RECETOX, Research Centre for Environmental Chemistry and Ecotoxicology, Masaryk University, Kamenice 126/3, 625 00 Brno (Czech Republic); Trapp, Stefan [Department of Environmental Engineering, Technical University of Denmark, Miljoevej 113, DK-2800 Kgs. Lyngby (Denmark); Klanova, Jana [RECETOX, Research Centre for Environmental Chemistry and Ecotoxicology, Masaryk University, Kamenice 126/3, 625 00 Brno (Czech Republic)], E-mail: klanova@recetox.muni.cz
2009-02-15
Uptake of organochlorine pesticides and polychlorinated biphenyls from soil and air into radishes was measured at a heavily contaminated field site. The highest contaminant concentrations were found for DDT and its metabolites, and for {beta}-hexachlorocyclohexane. Bioconcentration factor (BCF, defined as a ratio between the contaminant concentration in the plant tissue and concentration in soil) was determined for roots, edible bulbs and shoots. Root BCF values were constant and not correlated to log K{sub OW}. A negative correlation between BCF and log K{sub OW} was found for edible bulbs. Shoot BCF values were rather constant and varied between 0.01 and 0.22. Resuspended soil particles may facilitate the transport of chemicals from soil to shoots. Elevated POP concentrations found in shoots of radishes grown in the control plot support the hypothesis that the uptake from air was more significant for shoots than the one from soil. The uptake of POPs from air was within the range of theoretical values predicted from log K{sub OA}. - Uptake from air represented for majority of persistent organochlorines a dominant pathway into shoots while uptake from soil was dominant for roots.
5. Dietary taurine alters ascorbic acid metabolism in rats fed diets containing polychlorinated biphenyls.
Science.gov (United States)
Mochizuki, H; Oda, H; Yokogoshi, H
2000-04-01
The effect of dietary taurine on ascorbic acid metabolism and hepatic drug-metabolizing enzymes was investigated in rats fed diets containing polychlorinated biphenyls (PCB) to determine whether taurine has an adaptive and protective function in xenobiotic-treated animals. Young male Wistar rats (60 g) were fed diets containing 0 or 0.2 g/kg diet PCB with or without 30 g/kg diet of taurine for 14 d. The rats fed the PCB-containing diets had greater liver weight, higher ascorbic acid concentrations in the liver and spleen and greater hepatic cytochrome P-450 contents than control rats that were not treated with PCB (P ascorbic acid excretion was enhanced, and serum cholesterol concentration (especially HDL-cholesterol) was significantly elevated compared with those in control rats. Dietary taurine significantly potentiated the increases in the urinary excretion of ascorbic acid and the rise in the levels of cytochrome P-450 which were caused by PCB treatment. On the other hand, the supplementation of taurine to control diet did not alter these variables. Taurine may enhance the hepatic drug-metabolizing systems, leading to the stimulation of the ascorbic acid metabolism in rats fed diets containing PCB.
6. Inhibition of LPS-induced splenocyte proliferation by ortho-substituted polychlorinated biphenyl congeners
International Nuclear Information System (INIS)
Smithwick, L. Ashley; Smith, Andrew; Quensen, John F.; Stack, Allison; London, Lucille; Morris, Pamela J.
2003-01-01
Polychlorinated biphenyls (PCBs) are persistent environmental contaminants, and their ubiquitous nature has prompted studies of their potential health hazards. As a result of their lipophilic nature, PCBs accumulate in breast milk and subsequently affect the health of offspring of exposed individuals. Biological effects of PCBs in animals have mostly been attributed to coplanar congeners, although effects of ortho congeners also have been demonstrated. To investigate the relationship of immunotoxicity and chlorine substitution pattern, the effects of PCB congeners and mixtures of ortho and non-ortho-substituted constituents of Aroclor 1242 on splenocytes from C57B1/6 mice were examined. The immunotoxic endpoints investigated included splenocyte viability, lipopolysaccharide (LPS)-induced splenocyte proliferation, and LPS-induced antibody secretion. Congeners with multiple ortho chlorines preferentially inhibited splenocyte proliferation as compared with non- or mono-ortho-substituted congeners. However, mixtures of non- and mono-ortho-substituted congeners and multi-ortho-substituted congeners inhibited LPS-induced splenocyte proliferation and antibody secretion at similar concentrations. Exposure of splenocytes to these mixtures did not activate the aryl hydrocarbon receptor (AhR) signal transduction pathway. These results suggest individual multi-ortho-substituted congeners preferentially inhibit LPS-induced splenocyte proliferation, while congeners not exhibiting an effect individually may have additive effects in a mixture to produce an immunotoxic response through an AhR-independent pathway
7. Polychlorinated biphenyls in alfalfa: Accumulation, sorption and speciation in different plant parts.
Science.gov (United States)
Teng, Ying; Sun, Xianghui; Zhu, Lingjia; Christie, Peter; Luo, Yongming
2017-08-03
The accumulation, chemical speciation and distribution of polychlorinated biphenyls (PCBs) were investigated in various parts of alfalfa. Moreover, the adsorption characteristics for PCB 28 by alfalfa and the influencing factors of the adsorption characteristics were studied. There were different degrees of PCB accumulation in alfalfa roots, root nodules and shoots. The decreasing order of the accumulation of PCBs in plant tissues was root nodules > roots > shoots, and the decreasing order of the total PCB contents was roots > shoots > root nodules, indicating that the roots were the main sink for PCB accumulation. There were three modes of PCB speciation in alfalfa roots and root nodules, comprising strong sorption (78%) and weak sorption (19%) on tissue surfaces and absorption within tissues (2%). The adsorption isotherms of PCB 28 indicate that the adsorption capacities of root nodules and shoots were both significantly higher than that of the roots. Both lipids and carbohydrates, and especially lipids, affected the PCB adsorption capacities of the tissues. These results may help in the elucidation of the mechanisms of sorption and accumulation of PCBs in the plants and their main influencing factors and thus contribute to the development of phytoremediation technologies for PCB-contaminated soils.
8. Structural insights into the metabolism of 2-chlorodibenzofuran by an evolved biphenyl dioxygenase
Energy Technology Data Exchange (ETDEWEB)
Kumar, Pravindra; Mohammadi, Mahmood; Dhindwal, Sonali; Pham, Thi Thanh My; Bolin, Jeffrey T.; Sylvestre, Michel (INRS); (IIT-India); (Purdue)
2012-06-28
The biphenyl dioxygenase of Burkholderia xenovorans LB400 (BphAE{sub LB400}) is a Rieske-type oxygenase that catalyzes the stereospecific oxygenation of many heterocyclic aromatics including dibenzofuran. In a previous work, we evolved BphAE{sub LB400} and obtained BphAE{sub RR41}. This variant metabolizes dibenzofuran and 2-chlorodibenzofuran more efficiently than BphAE{sub LB400}. However, the regiospecificity of BphAE{sub RR41} toward these substrates differs. Dibenzofuran is metabolized principally through a lateral dioxygenation whereas 2-chlorodibenzofuran is metabolized principally through an angular dioxygenation. In order to explain this difference, we examined the crystal structures of both substrate-bound forms of BphAE{sub RR41} obtained under anaerobic conditions. This structure analysis, in combination with biochemical data for a Ser283Gly mutant provided evidences that the substrate is compelled to move after oxygen-binding in BphAE{sub RR41}:dibenzofuran. In BphAE{sub RR41}:2-chlorodibenzofuran, the chlorine atom is close to the side chain of Ser283. This contact is missing in the BphAE{sub RR41}:dibenzofuran, and strong enough in the BphAE{sub RR41}:2-chlorodibenzofuran to help prevent substrate movement during the catalytic reaction.
9. Advances and perspective in bioremediation of polychlorinated biphenyl-contaminated soils.
Science.gov (United States)
Sharma, Jitendra K; Gautam, Ravindra K; Nanekar, Sneha V; Weber, Roland; Singh, Brajesh K; Singh, Sanjeev K; Juwarkar, Asha A
2018-06-01
10. Congener-specific egg contribution of polychlorinated biphenyls to nestlings in two passerine species
Energy Technology Data Exchange (ETDEWEB)
Maul, Jonathan D., E-mail: jonathan.maul@tiehh.ttu.ed [Department of Environmental Toxicology, Institute of Environmental and Human Health (TIEHH), Texas Tech University, Lubbock, TX 79409 (United States); Schuler, Lance J. [Fisheries and Illinois Aquaculture Center and Department of Zoology, Southern Illinois University, Carbondale, IL 62901 (United States); Halbrook, Richard S. [Cooperative Wildlife Research Laboratory and Department of Zoology, Southern Illinois University, Carbondale, IL 62901 (United States); Lydy, Michael J. [Fisheries and Illinois Aquaculture Center and Department of Zoology, Southern Illinois University, Carbondale, IL 62901 (United States)
2010-08-15
Quantifying polychlorinated biphenyl (PCB) residues in nestlings of avian species is a common method for assessing trophic transfer and risk at PCB-contaminated sites. The proportion of nestling PCB mass due to maternal transfer is often accounted for by subtracting total PCB mass in eggs from nestlings. However, variation in physicochemical properties and metabolism among congeners may lead to differences between egg contribution based on total PCBs and dioxin-like congeners. We examined congener-specific variation in contribution of PCBs from eggs to nestlings in tree swallows and European starlings. Egg contribution of total PCB mass was 14.3 and 16.2%, respectively, whereas contribution based on dioxin-like congeners was 14.8 and 13.6%, respectively. These data suggest that using total PCB mass in eggs to adjust estimates of PCB accumulation in nestlings may not reflect patterns for dioxin-like congeners, potentially over or under-estimating the risk of toxicity of PCBs. - Congener-specific contribution of PCBs from egg to nestlings was examined.
11. Polychlorinated biphenyls in polysulfide sealants-Occurrence and emission from a landfill station
International Nuclear Information System (INIS)
Persson, N. Johan; Pettersen, Harald; Ishaq, Rasha; Axelman, Johan; Bandh, Cecilia; Broman, Dag; Zebuehr, Yngve; Hammar, Tommy
2005-01-01
Approximately 80 000 kg polysulfide sealant containing 10 000-18 000 kg polychlorinated biphenyls (PCB) was deposited at a Swedish municipal landfill station during 1965-1973. Investigations during 1994 showed that soil layers underneath the landfill had concentration of PCB not alarmingly high. The concentration of PCB congeners in ground water samples was elevated 4-750 times compared to a reference sample. Based on samples of ground water, leachate water, and flux chambers measuring evaporation of PCB from the landfill surface, the emission of PCB was estimated to be 1 g ΣPCB/yr. This very low rate was attributed to the high sorptive capacity of the sealant. Compared to a reference site, the evaporation flux was elevated for the most volatile congeners, but factors 20-1400 lower than from another landfill which was contaminated with PCB in paper-pulp fibres. - From a municipal 2-ha landfill containing 10-18 tonnes of ΣPCB bound in polysulfide sealants, only 1 g per year escape to the surroundings
12. Polychlorinated biphenyls in freshwater salmonids from the Kerguelen Islands in the Southern Ocean
International Nuclear Information System (INIS)
Jaffal, A.; Givaudan, N.; Betoulle, S.; Terreau, A.; Paris-Palacios, S.; Biagianti-Risbourg, S.; Beall, E.; Roche, H.
2011-01-01
The Subantarctic Kerguelen Islands (49 o S, 70 o E) contain freshwater ecosystems among the most isolated in the world. Concentrations of polychlorinated biphenyls (PCBs) were assessed in the muscle of 48 brook trout and 38 brown trout caught during summer and spring 2006 in the rivers, lakes and ponds of Kerguelen. The sum of 29 PCBs averaged 404 and 358 ng g -1 lipid, and dioxin-like PCB was 19 and 69 ng g -1 lipid, in brook and brown trout, respectively. The values showed a high variability and some fish accumulated PCBs at levels similar to those of fish from impacted areas. While inter-sex differences were limited, the season and the morphotype appeared to have the most influence. Fish captured in summer had muscle PCB concentrations about three times higher than those caught in spring and the 'river' morphotype of brook trout showed the highest PCB levels. - Highlights: → First assessment of PCB contamination of biota in Kerguelen Islands, Sub-Antarctica. → PCB bioaccumulation level in trout varies from very high to undetectable. → Habitat and morphotype are the most influential factors on the variability. → Distribution pattern of PCBs in the muscle of fish is morphotype dependent. - Salmonids in hydrosystems of the Kerguelen Islands (Southern Ocean) show a high PCB bioaccumulation.
13. High-pressure extraction of polychlorinated biphenyls from soils and other fine-grained solids
International Nuclear Information System (INIS)
Markowz, G.
1996-12-01
Four doped and three really contaminated samples were subjected to high-pressure PCB (polychlorinated biphenyl) extraction in a laboratory-scale experimental plant using CO 2 (carbon dioxide) as solvent. The PCB levels (sum out of the six key substances) of the real samples were 2.6, 6.8, and 139 mg/kg. The success of the cleaning process was determined by measuring the residual PCB levels in the soil after the extraction. Parameters were varied and samples were taken selectively from various points in the bed (length 270 mm, diameter 14 mm, weighed - in soil 50-60 g) in order to gain an idea of the effects of upscaling. The following parameters were varied: extraction temperature 40-90 C; extraction pressure 200-300 bar; CO 2 flow rate 3.6-14.6 g/min; CO 2 quantity 0-328 g; degree of contamination (doped samples) 12-60 mg/kg; soil moisture 0-15%; particle size 0-2000 μm; entraining agent methanol, ethanol, acetone; proportion of entraining agent 0-7.5% by weight. Furthermore the influence of moisture at the time of doping on extraction was examined. (orig./ABI) [de
14. Polychlorinated biphenyl (PCB) induction of CYP3A4 enzyme activity in healthy Faroese adults
DEFF Research Database (Denmark)
Petersen, Maria Skaalum; Halling, Jónrit; Damkier, Per
2007-01-01
The CYP3A4 enzyme is, along with other cytochrome P450 enzymes, involved in the metabolism of environmental pollutants and is highly inducible by these substances. A commercial polychlorinated biphenyl (PCB) mixture, 1,1,1,-trichloro-2-(o-chlorophenyl), 2-(p'-chlorophenyl)ethane (o,p'-DDT) and 1......,1,-dichloro-2,2-bis (p-chlorophenyl)ethene (p,p'-DDE) are known to induce CYP3A4 activity through activation of nuclear receptors, such as the pregnane X receptor. However, this induction of CYP3A4 has not yet been investigated in humans. Thus, the aim of the study was to determine the variability of the CYP3......A4 phenotype in regard to increased concentrations of PCBs and other persistent organohalogen pollutants (POPs) in healthy Faroese adults. In 310 randomly selected Faroese residents aged 18-60 years, the CYP3A4 activity was determined based on the urinary 6beta-hydroxycortisol/cortisol (6beta...
15. Insight into the structural requirement of substituted quinazolinone biphenyl acylsulfonamides derivatives as Angiotensin II AT1 receptor antagonist: 2D and 3D QSAR approach
Directory of Open Access Journals (Sweden)
Mukesh C. Sharma
2014-01-01
Full Text Available A series of 19 molecules substituted quinazolinone biphenyl acylsulfonamides derivatives displaying variable inhibition of Angiotensin II receptor AT1 activity were selected to develop models for establishing 2D and 3D QSAR. The compounds in the selected series were characterized by spatial, molecular and electro topological descriptors using QSAR module of Molecular Design Suite (VLife MDS™ 3.5. The best 2D QSAR model was selected, having correlation coefficient r2 (0.8056 and cross validated squared correlation coefficient q2 (0.6742 with external predictive ability of pred_r2 0.7583 coefficient of correlation of predicted data set (pred_r2se 0.2165. The results obtained from QSAR studies could be used in designing better Ang II activity among the congeners in future. The optimum QSAR model showed that the parameters SsssCHE index, SddCE-index, T_2_Cl_4, and SssNHE-index contributed in the model. 3D QSAR analysis by kNN-molecular field analysis approach developed based on principles of the k-nearest neighbor method combined with Genetic algorithms, stepwise forward variable selection approach; a leave-one-out cross-validated correlation coefficient (q2 of 0.6516 and a non-cross-validated correlation coefficient (r2 of 0.8316 and pred_r2 0.6954 were obtained. Contour maps using this approach showed that steric, electrostatic, and hydrophobic field effects dominantly determine binding affinities. The information rendered by 3D QSAR models may lead to a better understanding of structural requirements of Angiotensin II receptor and can help in the design of novel potent antihypertensive molecules.
16. Organic compounds in produced waters from coalbed natural gas wells in the Powder River Basin, Wyoming, USA
Science.gov (United States)
Orem, W.H.; Tatu, C.A.; Lerch, H.E.; Rice, C.A.; Bartos, T.T.; Bates, A.L.; Tewalt, S.; Corum, M.D.
2007-01-01
The organic composition of produced water samples from coalbed natural gas (CBNG) wells in the Powder River Basin, WY, sampled in 2001 and 2002 are reported as part of a larger study of the potential health and environmental effects of organic compounds derived from coal. The quality of CBNG produced waters is a potential environmental concern and disposal problem for CBNG producers, and no previous studies of organic compounds in CBNG produced water have been published. Organic compounds identified in the produced water samples included: phenols, biphenyls, N-, O-, and S-containing heterocyclic compounds, polycyclic aromatic hydrocarbons (PAHs), aromatic amines, various non-aromatic compounds, and phthalates. Many of the identified organic compounds (phenols, heterocyclic compounds, PAHs) are probably coal-derived. PAHs represented the group of organic compounds most commonly observed. Concentrations of total PAHs ranged up to 23 ??g/L. Concentrations of individual compounds ranged from about 18 to compound concentrations was documented, as two wells with relatively high organic compound contents in produced water in 2001 had much lower concentrations in 2002. In many areas, including the PRB, coal strata provide aquifers for drinking water wells. Organic compounds observed in produced water are also likely present in drinking water supplied from wells in the coal. Some of the organic compounds identified in the produced water samples are potentially toxic, but at the levels measured in these samples are unlikely to have acute health effects. The human health effects of low-level, chronic exposure to coal-derived organic compounds in drinking water are currently unknown. Continuing studies will evaluate possible toxic effects from low level, chronic exposure to coal-derived organic compounds in drinking water supplies.
17. Lipid–water partition coefficients and correlations with uptakes by algae of organic compounds
International Nuclear Information System (INIS)
Hung, Wei-Nung; Chiou, Cary T.; Lin, Tsair-Fuh
2014-01-01
Graphical abstract: - Highlights: • Partition coefficients of contaminants with lipid triolein (K tw ) are measured. • Measured K tw values are nearly the same as the respective K ow . • Sorption of the contaminants to a dry algal powder is similarly measured. • Algal uptake of a compound occurs primarily by partition into the algal lipid. - Abstract: In view of the scarcity of the lipid–water partition coefficients (K tw ) for organic compounds, the log K tw values for many environmental contaminants were measured using ultra-pure triolein as the model lipid. Classes of compounds studied include alkyl benzenes, halogenated benzenes, short-chain chlorinated hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine pesticides. In addition to log K tw determination, the uptakes of these compounds from water by a dry algal species were measured to evaluate the lipid effect on the algal uptake. The measured log K tw are closely related to their respective log K ow (octanol–water), with log K ow = 1.9 to 6.5. A significant difference is observed between the present and early measured log K tw for compounds with log K ow > ∼5, which is attributed to the presence and absence of a triolein microemulsion in water affecting the solute partitioning. The observed lipid-normalized algae–water distribution coefficients (log K aw/lipid ) are virtually identical to the respective log K tw values, which manifests the dominant lipid-partition effect of the compounds with algae
18. Formation of highly oxygenated organic molecules from aromatic compounds
Science.gov (United States)
Molteni, Ugo; Bianchi, Federico; Klein, Felix; El Haddad, Imad; Frege, Carla; Rossi, Michel J.; Dommen, Josef; Baltensperger, Urs
2018-02-01
Anthropogenic volatile organic compounds (AVOCs) often dominate the urban atmosphere and consist to a large degree of aromatic hydrocarbons (ArHCs), such as benzene, toluene, xylenes, and trimethylbenzenes, e.g., from the handling and combustion of fuels. These compounds are important precursors for the formation of secondary organic aerosol. Here we show that the oxidation of aromatics with OH leads to a subsequent autoxidation chain reaction forming highly oxygenated molecules (HOMs) with an O : C ratio of up to 1.09. This is exemplified for five single-ring ArHCs (benzene, toluene, o-/m-/p-xylene, mesitylene (1,3,5-trimethylbenzene) and ethylbenzene), as well as two conjugated polycyclic ArHCs (naphthalene and biphenyl). We report the elemental composition of the HOMs and show the differences in the oxidation patterns of these ArHCs. A potential pathway for the formation of these HOMs from aromatics is presented and discussed. We hypothesize that AVOCs may contribute substantially to new particle formation events that have been detected in urban areas.
19. Formation of highly oxygenated organic molecules from aromatic compounds
Directory of Open Access Journals (Sweden)
U. Molteni
2018-02-01
Full Text Available Anthropogenic volatile organic compounds (AVOCs often dominate the urban atmosphere and consist to a large degree of aromatic hydrocarbons (ArHCs, such as benzene, toluene, xylenes, and trimethylbenzenes, e.g., from the handling and combustion of fuels. These compounds are important precursors for the formation of secondary organic aerosol. Here we show that the oxidation of aromatics with OH leads to a subsequent autoxidation chain reaction forming highly oxygenated molecules (HOMs with an O : C ratio of up to 1.09. This is exemplified for five single-ring ArHCs (benzene, toluene, o-/m-/p-xylene, mesitylene (1,3,5-trimethylbenzene and ethylbenzene, as well as two conjugated polycyclic ArHCs (naphthalene and biphenyl. We report the elemental composition of the HOMs and show the differences in the oxidation patterns of these ArHCs. A potential pathway for the formation of these HOMs from aromatics is presented and discussed. We hypothesize that AVOCs may contribute substantially to new particle formation events that have been detected in urban areas.
20. Atropisomerism: the effect of the axial chirality in bioactive compounds; Atropoisomerismo: o efeito da quiralidade axial em substancias bioativas
Energy Technology Data Exchange (ETDEWEB)
Santos, Anderson Rouge dos; Pinheiro, Alessandra Campbell; Sodero, Ana Carolina Renno; Cunha, Andrea Sousa da; Padilha, Monica Costa; Sousa, Priscila Mesquita de; Fontes, Silvia Paredes [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Quimica. Dept. de Quimica Organica; Veloso, Marcia Paranho [Universidade Federal de Alfenas, MG (Brazil); Fraga, Carlos Alberto Manssour [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Faculdade de Farmacia. Lab. de Avaliacao e Sintese de Substancias Bioativas (LASSBio)]. E-mail: cmfraga@pharma.ufrj.br
2007-01-15
Atropisomerism is a special kind of stereoisomeric relationship that arises from the freezing of a certain conformation of an organic molecule, associated with a high rotational barrier about a single covalent bond. Atropisomerism has been originally described in orto-functionalized biphenyl derivatives, but a lot of other organic functionalities can present this structural phenomenon, characterized by the presence of chiral properties in compounds that do not present classical stereogenic centers. Atropisomeric compounds, intermediates and catalysts have well-know importance in organic synthesis, but the influence of the axial chirality in substances able to modulate biological systems is still not very exploited in drug design and development. In this context, the present account describes the importance of this structural property in the medicinal chemistry of different classes of bioactive compounds or therapeutic agents, emphasizing how atropisomerism could affect the molecular recognition of a ligand or a prototype by the target bioreceptor. (author)
1. Structure determination of two structural analogs, named 3-[1-(2-fluoro-4-biphenyl)ethyl]-6-(4-fluorophenyl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole (C23H16F2N4S) and 3-[1-(2-fluoro-4-biphenyl)ethyl]-6-(4-chlorophenyl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole (C23H16ClFN4S) by synchrotron X-ray powder diffraction
Energy Technology Data Exchange (ETDEWEB)
Gündoğdu, Gülsüm; Aytaç, Sevim Peri; Müller, Melanie; Tozkoparan, Birsen; Kaynak, Filiz Betül
2017-12-01
Two novel compounds, 3-[1-(2-fluoro-4-biphenyl)ethyl]-6-(4-fluorophenyl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole (C23H16F2N4S) (1) and 3-[1-(2-fluoro-4-biphenyl)ethyl]-6-(4-chlorophenyl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole (C23H16ClFN4S) (2), have been designed and synthesized as cytotoxic agents. The compounds were characterized by infrared, proton nuclear magnetic resonance, mass spectral data, elemental analysis and X-ray powder diffraction. The present study comprises spectral data and crystal structures of these novel compounds determined from synchrotron X-ray powder diffraction data. The structure solutions were obtained by simulated annealing. The final structures were achieved by Rietveld refinement using soft restraints for all bond lengths, bond angles, and planar groups. Both compounds crystallize in space group$P\\bar 1$,Z= 2, with the unit-cell parametersa= 6.37433(9),b= 11.3641(2),c= 14.09115(19) Å,α= 80.1740(8)°,β= 85.1164(8)°,γ= 80.9831(10)°,V= 991.55(3) Å3of compound (1) anda= 6.53736(6),b= 11.55725(15),c= 14.01373(13) Å,α= 80.3323(7)°,β= 84.8939(6)°,γ= 79.3954(8)°,V= 1024.08(2) Å3of compound (2). Structural analyses reveal that the title compounds are isostructural.
2. Stable isotopes labelled compounds
International Nuclear Information System (INIS)
1982-09-01
The catalogue on stable isotopes labelled compounds offers deuterium, nitrogen-15, and multiply labelled compounds. It includes: (1) conditions of sale and delivery, (2) the application of stable isotopes, (3) technical information, (4) product specifications, and (5) the complete delivery programme
3. Dehalogenation of Polybrominated Diphenyl Ethers and Polychlorinated Biphenyl by Bimetallic, Impregnated, and Nanoscale Zerovalent Iron
Science.gov (United States)
Zhuang, Yuan; Ahn, Sungwoo; Seyfferth, Angelia L.; Masue-Slowey, Yoko; Fendorf, Scott; Luthy, Richard G.
2011-01-01
Nanoscale zerovalent iron particles (nZVI), bimetallic nanoparticles (nZVI/Pd), and nZVI/Pd impregnated activated carbon (nZVI/Pd-AC) composite particles were synthesized and investigated for their effectiveness to remove polybrominated diphenyl ethers (PBDEs) and/or polychlorinated biphenyls (PCBs). Palladization of nZVI promoted the dehalogenation kinetics for mono- to tri-BDEs and 2,3,4-trichlorobiphenyl (PCB 21). Compared to nZVI, the iron-normalized rate constants for nZVI/Pd were about 2-, 3-, and 4-orders of magnitude greater for tri-, di-, and mono-BDEs, respectively, with diphenyl ether as a main reaction product. The reaction kinetics and pathways suggest an H-atom transfer mechanism. The reaction pathways with nZVI/Pd favor preferential removal of para-halogens on PBDEs and PCBs. X-ray fluorescence mapping of nZVI/Pd-AC showed that Pd mainly deposits on the outer part of particles, while Fe was present throughout the activated carbon particles. While BDE 21 was sorbed onto activated carbon composites quickly, debromination was slower compared to reaction with freely dispersed nZVI/Pd. Our XPS and chemical data suggest about 7% of the total iron within the activated carbon was zero-valent, which shows the difficulty with in-situ synthesis of a significant fraction of zero-valent iron in the micro-porous material. Related factors that likely hinder the reaction with nZVI/Pd-AC are the heterogenous distribution of nZVI and Pd on activated carbon and/or immobilization of hydrophobic organic contaminants at the adsorption sites thereby inhibiting contact with nZVI. PMID:21557574
4. Reproductive dysfunction in rhesus monkeys exposed to low levels of polychlorinated biphenyls (Aroclor 1248)
Energy Technology Data Exchange (ETDEWEB)
Barsotti, D.A.; Marlar, R.J.; Allen, J.R.
1976-01-01
Eighteen female and four male adult Rhesus monkeys were fed the polychlorinated biphenyl (PCB) Aroclor 1248 at levels of either 2.5 or 5.0 ppM in the diet. These levels are equal to, and 50% of, the concentration allowed in certain foods destined for human consumption. After consuming these diets for 2 months, some of the females developed acne, alopecia, erythema and swelling of the eyelids, and by 6 months all females exhibited these changes to some degree. Modifications in serum lipids developed gradually, with a trend towards hypocholesterolaemia, hypolipidaemia and decreased serum triglycerides. In addition there was a shift in the plasma albumin/globulin ratio and an increase in serum glutamic-pyruvic transaminase activity. Analysis of subcutaneous fat showed an accumulation of the PCB isomers in the adipose tissue. The concentrations in this tissue reached a plateau, after which only slight variations were observed. Within 4 months, menstrual cycles were altered: menostaxis and menorrhagia occurred frequently and at times amenorrhoea was apparent. The ability of the animals to maintain pregnancy was impaired, as indicated by frequent resorptions and abortions. When infants were born they were small, and the transplacental movement of PCBs was evident from analyses of skin biopsies of neonates and of autopsy tissue from one stillborn. Moreover, additional accumulation of PCBs occurred in infants during breast feeding. All males fed 5.0 ppM PCB exhibited only slight periorbital oedema and erythema after 14 months on the diet and showed no alterations in their breeding capacities. The data presented indicate that long-term, low-level exposure of female non-human primates to PCBs can affect many important biological parameters.
5. Independent review of inappropriate identification, storage and treatment methods of polychlorinated biphenyl waste streams
International Nuclear Information System (INIS)
1997-07-01
The purpose of the review was to evaluate incidents involving the inappropriate identification, storage, and treatment methods associated with polychlorinated biphenyl (PCB) waste streams originating from the V-tank system at the Test Area North (TAN). The team was instructed to perform a comprehensive review of Lockheed Martin Idaho Technologies Company (LMITCO's) compliance programs related to these incidents to assess the adequacy and effectiveness of the management program in all respects including: adequacy of the waste management program in meeting all LMITCO requirements and regulations; adequacy of policies, plans, and procedures in addressing and implementing all federal and state requirements and regulations; and compliance status of LMITCO, LMITCO contract team members, and LMITCO contract/team member subcontractor personnel with established PCB management policies, plans, and procedures. The V-Tanks are part of an intermediate waste disposal system and are located at the Technical Support Facility (TSF) at TAN at the Idaho National Engineering and Environmental Laboratory (INEEL). The IRT evaluated how a waste was characterized, managed, and information was documented; however, they did not take control of wastes or ensure followup was performed on all waste streams that may have been generated from the V-Tanks. The team has also subsequently learned that the Environmental Restoration (ER) program is revising the plans for the decontamination and decommissioning of the intermediate waste disposal system based on new information listed and PCB wastes. The team has not reviewed those in-process changes. The source of PCB in the V-Tank is suspected to be a spill of hydraulic fluid in 1968
6. Polychlorinated biphenyls in the exterior caulk of San Francisco Bay Area buildings, California, USA.
Science.gov (United States)
Klosterhaus, Susan; McKee, Lester J; Yee, Donald; Kass, Jamie M; Wong, Adam
2014-05-01
Extensive evidence of the adverse impacts of polychlorinated biphenyls (PCBs) to wildlife, domestic animals, and humans has now been documented for over 40 years. Despite the ban on production and new use of PCBs in the United States in 1979, a number of fish consumption advisories remain in effect, and there remains considerable uncertainty regarding ongoing environmental sources and management alternatives. Using a blind sampling approach, 25 caulk samples were collected from the exterior of ten buildings in the San Francisco Bay Area and analyzed for PCBs using congener-specific gas chromatography-mass spectrometry (GC-MS) and chlorine using portable X-ray fluorescence (XRF). PCBs were detected in 88% of the caulk samples collected from the study area buildings, with 40% exceeding 50 ppm. Detectable PCB concentrations ranged from 1 to 220,000 ppm. These data are consistent with previous studies in other cities that have identified relatively high concentrations of PCBs in concrete and masonry buildings built between 1950 and 1980. Portable XRF was not a good predictor of the PCB content in caulk and the results indicate that portable XRF analysis may only be useful for identifying caulk that contains low concentrations of Cl (≤ 10,000 ppm) and by extension low or no PCBs. A geographic information system-based approach was used to estimate that 10,500 kg of PCBs remain in interior and exterior caulk in buildings located in the study area, which equates to an average of 4.7 kg PCBs per building. The presence of high concentrations in the exterior caulk of currently standing buildings suggests that building caulk may be an ongoing source of PCBs to the San Francisco Bay Area environment. Further studies to expand the currently small international dataset on PCBs in caulking materials in buildings of countries that produced or imported PCBs appear justified in the context of both human health and possible ongoing environmental release. Copyright © 2014 Elsevier
7. Polychlorinated biphenyl exposure and corticosterone levels in seven polar seabird species
International Nuclear Information System (INIS)
Tartu, S.; Angelier, F.; Bustnes, J.O.; Moe, B.; Hanssen, S.A.; Herzke, D.; Gabrielsen, G.W.; Verboven, N.; Verreault, J.; Labadie, P.; Budzinski, H.; Wingfield, J.C.
2015-01-01
The role of polychlorinated biphenyls (PCBs) on exposure-related endocrine effects has been poorly investigated in wild birds. This is the case for stress hormones including corticosterone (CORT). Some studies have suggested that environmental exposure to PCBs and altered CORT secretion might be associated. Here we investigated the relationships between blood PCB concentrations and circulating CORT levels in seven free-ranging polar seabird species occupying different trophic positions, and hence covering a wide range of PCB exposure. Blood ∑ 7 PCB concentrations (range: 61–115,632 ng/g lw) were positively associated to baseline or stress-induced CORT levels in three species and negatively associated to stress-induced CORT levels in one species. Global analysis suggests that in males, baseline CORT levels generally increase with increasing blood ∑ 7 PCB concentrations, whereas stress-induced CORT levels decrease when reaching high blood ∑ 7 PCB concentrations. This study suggests that the nature of the PCB-CORT relationships may depend on the level of PCB exposure. - Highlights: • Relationships between PCBs and stress hormones (CORT) are not well known in birds. • We measured blood PCBs, baseline and stress-induced CORT in seven seabird species. • ∑PCB was positively associated to baseline or stress-induced CORT in three species. • ∑PCBs was negatively linked to stress-induced CORT in the most contaminated species. • The nature of the PCB-CORT relationships may depend on the level of PCB exposure. - In polar seabird species, the relationship between PCB and CORT concentrations may be related to the levels of contamination
8. Allee effect in polar bears: a potential consequence of polychlorinated biphenyl contamination.
Science.gov (United States)
Pavlova, Viola; Nabe-Nielsen, Jacob; Dietz, Rune; Sonne, Christian; Grimm, Volker
2016-11-30
Polar bears (Ursus maritimus) from East Greenland and Svalbard exhibited very high concentrations of polychlorinated biphenyls (PCBs) in the 1980s and 1990s. In Svalbard, slow population growth during that period was suspected to be linked to PCB contamination. In this case study, we explored how PCBs could have impacted polar bear population growth and/or male reproductive success in Svalbard during the mid-1990s by reducing the fertility of contaminated males. A dose-response relationship linking the effects of PCBs to male polar bear fertility was extrapolated from studies of the effects of PCBs on sperm quality in rodents. Based on this relationship, an individual-based model of bear interactions during the breeding season predicted fertilization success under alternative assumptions regarding male-male competition for females. Contamination reduced pregnancy rates by decreasing the availability of fertile males, thus triggering a mate-finding Allee effect, particularly when male-male competition for females was limited or when infertile males were able to compete with fertile males for females. Comparisons of our model predictions on age-dependent reproductive success of males with published empirical observations revealed that the low representation of 10-14-year-old males among breeding males documented in Svalbard in mid-1990s could have resulted from PCB contamination. We conclude that contamination-related male infertility may lead to a reduction in population growth via an Allee effect. The magnitude of the effect is largely dependent on the population-specific mating system. In eco-toxicological risk assessments, appropriate consideration should therefore be given to negative effects of contaminants on male fertility and male mating behaviour. © 2016 The Author(s).
9. Developmental and neurobehavioral effects of perinatal exposure to polychlorinated biphenyls in mice.
Science.gov (United States)
Sugawara, Norio; Nakai, Kunihiko; Nakamura, Tomoyuki; Ohba, Takashi; Suzuki, Keita; Kameo, Satomi; Satoh, Chieko; Satoh, Hiroshi
2006-05-01
Because behavioral deficits associated with gestational exposure to polychlorinated biphenyls (PCBs) have been a concern, we studied the developmental and neurobehavioral effects of perinatal exposure to Aroclor 1254 (A1254), a commercial mixture of PCBs, in mice. The PCB mixture (A1254; 0, 6, 18, and 54 mg/kg body weight) was administered to pregnant mice (C57BL/6Cr) every 3 days by gavage from gestational day (GD) 6 to postnatal day (PND) 20. Compared with the control, treatment with A1254 did not alter the maternal body weight during the gestation and lactation periods. The body weight of the offspring did not differ among treatments. To assess the effects on offspring following such exposure, physical and neurobehavioral development (i.e., pinna detachment, hair growth, eye opening, incisor eruption, grasp reflex, righting reflex, walking, negative geotaxis, and cliff avoidance) was observed before weaning. At PND 7, poor adult-like responses in negative geotaxis were observed in all exposed groups. When the offspring were at 8-week old, the PCB-treated (18 mg/kg body weight) mice showed a decreased walking speed in the open-field test, and a prolonged time to reach the platform in the water maze test. Spontaneous locomotion activity was not affected by PCB exposure at 9 weeks . These results showed that perinatal exposure to PCBs produces several behavioral alterations in mice. Although dose-dependent changes were not observed, the neurobehavioral effects such as a decreased walking speed in the open-field test and a prolonged time to reach the platform in the water maze test remained in adulthood after the seeming recovery from the transient delay in development before weaning.
10. Polychlorinated biphenyl and heavy metal exposures among fishermen in the Straits of Malacca: neurobehavioural performance.
Science.gov (United States)
2015-01-01
The aim of this study was to determine the level of exposure to polychlorinated biphenyls (PCBs) and selected heavy metals among fishermen via dietary intake of fish and other seafood from the eastern coast along the Straits of Malacca. This study determined the neurobehavioural performances (based on neurobehavioural core test battery scores) of the fishermen and evaluated the correlations between scores of neurobehavioural core test battery and exposure factors. Ninety fishermen participated in the study. The total fish intakes of the fishermen were measured using a set of food frequency questionnaires. The PCBs contents in the seafood samples ranged between 0.2 and 0.6 pg/g fresh sample. The concentrations of mercury (Hg), arsenic (As), cadmium (Cd), and lead (Pb) in the seafood samples were 1.1-5.4, 0.3-4.4, 0.6-36.1, and 0.02-0.3 μg/g fresh sample, respectively. The PCBs, Hg, As, Cd, and Pb exposures of the fishermen was estimated to be 2.8, 0.02, 4.5, 0.09, and 0.5 pg/kg body weight/day, respectively. PCB and heavy metal exposures through dietary intake of fish and seafood were within the tolerable daily limits. The results of neurobehavioural core test battery revealed that the neurobehavioural performances of the fishermen were not affected due to PCB and heavy metal intoxication. No correlations were found between the exposure and neurobehavioural performance among the fishermen. These data are useful for policy makers to assure the safety and quality of seafood in relation to sea pollution. Although the levels of exposure were low, periodic assessment of the quality of fish and fish products is required due to the polluted seawater.
11. Historical reconstruction of polychlorinated biphenyl (PCB) exposures for workers in a capacitor manufacturing plant.
Science.gov (United States)
Hopf, Nancy B; Ruder, Avima M; Waters, Martha A
2014-05-01
We developed a semiquantitative job exposure matrix (JEM) for workers exposed to polychlorinated biphenyls (PCBs) at a capacitor manufacturing plant from 1946 to 1977. In a recently updated mortality study, mortality of prostate and stomach cancer increased with increasing levels of cumulative exposure estimated with this JEM (trend p values = 0.003 and 0.04, respectively). Capacitor manufacturing began with winding bales of foil and paper film, which were placed in a metal capacitor box (pre-assembly), and placed in a vacuum chamber for flood-filling (impregnation) with dielectric fluid (PCBs). Capacitors dripping with PCB residues were then transported to sealing stations where ports were soldered shut before degreasing, leak testing, and painting. Using a systematic approach, all 509 unique jobs identified in the work histories were rated by predetermined process- and plant-specific exposure determinants; then categorized based on the jobs' similarities (combination of exposure determinants) into 35 job exposure categories. The job exposure categories were ranked followed by a qualitative PCB exposure rating (baseline, low, medium, and high) for inhalation and dermal intensity. Category differences in other chemical exposures (solvents, etc.) prevented further combining of categories. The mean of all available PCB concentrations (1975 and 1977) for jobs within each intensity rating was regarded as a representative value for that intensity level. Inhalation (in microgram per cubic milligram) and dermal (unitless) exposures were regarded as equally important. Intensity was frequency adjusted for jobs with continuous or intermittent PCB exposures. Era-modifying factors were applied to the earlier time periods (1946-1974) because exposures were considered to have been greater than in later eras (1975-1977). Such interpolations, extrapolations, and modifying factors may introduce non-differential misclassification; however, we do believe our rigorous method
12. Seasonal atmospheric deposition variations of polychlorinated biphenyls (PCBs) and comparison of some deposition sampling techniques.
Science.gov (United States)
2011-03-01
Ambient air and bulk deposition samples were collected between June 2008 and June 2009. Eighty-three polychlorinated biphenyl (PCB) congeners were targeted in the samples. The average gas and particle PCB concentrations were found as 393 ± 278 and 70 ± 102 pg/m(3), respectively, and 85% of the atmospheric PCBs were in the gas phase. Bulk deposition samples were collected by using a sampler made of stainless steel. The average PCB bulk deposition flux value was determined as 6,020 ± 4,350 pg/m(2) day. The seasonal bulk deposition fluxes were not statistically different from each other, but the summer flux had higher values. Flux values differed depending on the precipitation levels. The average flux value in the rainy periods was 7,480 ± 4,080 pg/m(2) day while the average flux value in dry periods was 5,550 ± 4,420 pg/m(2) day. The obtained deposition values were lower than the reported values given for the urban and industrialized areas, yet close to the ones for the rural sites. The reported deposition values were also influenced by the type of the instruments used. The average dry deposition and total deposition velocity values calculated based on deposition and concentration values were found as 0.23 ± 0.21 and 0.13 ± 0.13 cm/s, respectively.
13. Polychlorinated biphenyls and pesticides in surficial coastal sediments of the Ligurian Sea
Energy Technology Data Exchange (ETDEWEB)
Bertolotto, R.M.; Cuneo, C.; Albanese, S. [ARPAL, Direzione Scientifica, Genova (Italy); Magherini, A. [ARPAL, Dipartimento di Genova, Genova (Italy); Frignani, M.; Bellucci, L.G.; Alvarado-Aguilar, D. [ISMAR, Sezione di Geologia Marina, Bologna (Italy)
2004-09-15
Polychlorinated biphenyls (PCBs) and chlorinated pesticides, such as DDT and its analogues, are organic contaminants widespread throughout the terrestrial and oceanic environments due to their common use and their resistance to degradation. Since harmful effects have been associated to these chemicals and well documented, they are classified as priority pollutants by both the US Environmental Protection Agency (EPA) and the European Union. Because of the very low solubility in water and the tendency to adsorb onto sediment particles, the ultimate fate of both PCBs and DDTs in the marine environment is the incorporation into sediments. Hence, the concentrations of these chlorinate chemicals in bottom sediments can provide an insight on the quality of the environment and the potential threat to marine organisms and human beings. The Ligurian Sea belongs to the north part of the western Mediterranean. The coastal morphology of the Liguria Region is rather variable, and frequently cliffs drop sheer to the sea. The limited width of the coastal zone, comprised between the sea and the mountains, determined a gathering of the urban areas with a consequent concentration of both civil and industrial presence in a narrow but highly populated territory. In particular Genova, but also other cities have a long history of industrial and harbour activities, whereas long tracts of the coast are dedicated to tourism. The circulation of the Ligurian Sea is rather well known. In particular, surface and intermediate currents follow a cyclonic circulation. However local circulation is the true responsible of the dispersion of sediment material along the coast, and these alongshore currents often cause an eastward oriented transport. The Ligurian coastal zone is very developed, and hosts all sort of industrial, agricultural and tourist activities that can be sources of persistent organochlorine chemicals. Therefore, the purpose of this study was to assess concentrations, distributions
14. External heart deformities in passerine birds exposed to environmental mixtures of polychlorinated biphenyls during development.
Science.gov (United States)
DeWitt, Jamie C; Millsap, Deborah S; Yeager, Ronnie L; Heise, Steve S; Sparks, Daniel W; Henshel, Diane S
2006-02-01
Necropsy-observable cardiac deformities were evaluated from 283 nestling passerines collected from one reference site and five polychlorinated biphenyl (PCB)-contaminated sites around Bloomington and Bedford, Indiana, USA. Hearts were weighed and assessed on relative scales in three dimensions (height, length, and width) and for externally visible deformities. Heart weights normalized to body weight (heart somatic index) were decreased significantly at the more contaminated sites in both house wren (Troglodytes aedon) and tree swallow (Tachycineta bicolor). Heart somatic indices significantly correlated with log PCB concentrations in Carolina chickadee (Parus carolinesis) and tree swallow and with log 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalent values in tree swallow alone. Ventricular length was increased significantly in eastern bluebirds (Sialia sialis) and decreased significantly in Carolina chickadee and tree swallow from contaminated sites versus the reference site. Heart length regressed significantly against the log PCB concentrations (Carolina chickadee and tree swallow) or the square of the PCB concentrations (red-winged blackbird [Agelaius phoeniceus]) in a sibling bird. The deformities that were observed most at the contaminated sites included abnormal tips (pointed, rounded, or flattened), center rolls, macro- and microsurface roughness, ventricular indentations on the ventral or dorsal surface, lateral ventricular notches, visibly thin ventricular walls, and changes in overall heart shape. A pooled heart deformity index regressed significantly against the logged contaminant concentrations for all species except red-winged blackbird. These results indicate that developmental changes in heart morphometrics and shape abnormalities are quantifiable and may be sensitive and useful indicators of PCB-related developmental impacts across many avian species.
15. Neurodevelopmental toxicity of prenatal polychlorinated biphenyls (PCBs by chemical structure and activity: a birth cohort study
Directory of Open Access Journals (Sweden)
Park Hye-Youn
2010-08-01
Full Text Available Abstract Background Polychlorinated biphenyls (PCBs are ubiquitous environmental toxins. Although there is growing evidence to support an association between PCBs and deficits of neurodevelopment, the specific mechanisms are not well understood. The potentially different roles of specific PCB groups defined by chemical structures or hormonal activities e.g., dioxin-like, non-dioxin like, or anti-estrogenic PCBs, remain unclear. Our objective was to examine the association between prenatal exposure to defined subsets of PCBs and neurodevelopment in a cohort of infants in eastern Slovakia enrolled at birth in 2002-2004. Methods Maternal and cord serum samples were collected at delivery, and analyzed for PCBs using high-resolution gas chromatography. The Bayley Scales of Infant Development -II (BSID were administered at 16 months of age to over 750 children who also had prenatal PCB measurements. Results Based on final multivariate-adjusted linear regression model, maternal mono-ortho-substituted PCBs were significantly associated with lower scores on both the psychomotor (PDI and mental development indices (MDI. Also a significant association between cord mono-ortho-substituted PCBs and reduced PDI was observed, but the association with MDI was marginal (p = 0.05. Anti-estrogenic and di-ortho-substituted PCBs did not show any statistically significant association with cognitive scores, but a suggestive association between di-ortho-substituted PCBs measured in cord serum and poorer PDI was observed. Conclusion Children with higher prenatal mono-ortho-substituted PCB exposures performed more poorly on the Bayley Scales. Evidence from this and other studies suggests that prenatal dioxin-like PCB exposure, including mono-ortho congeners, may interfere with brain development in utero. Non-dioxin-like di-ortho-substituted PCBs require further investigation.
16. Polychlorinated biphenyl (PCB) induction of CYP3A4 enzyme activity in healthy Faroese adults
International Nuclear Information System (INIS)
Petersen, Maria Skaalum; Halling, Jonrit; Damkier, Per; Nielsen, Flemming; Grandjean, Philippe; Weihe, Pal; Brosen, Kim
2007-01-01
The CYP3A4 enzyme is, along with other cytochrome P450 enzymes, involved in the metabolism of environmental pollutants and is highly inducible by these substances. A commercial polychlorinated biphenyl (PCB) mixture, 1,1,1,-trichloro-2-(o-chlorophenyl), 2-(p'-chlorophenyl)ethane (o,p'-DDT) and 1,1,-dichloro-2,2-bis (p-chlorophenyl)ethene (p,p'-DDE) are known to induce CYP3A4 activity through activation of nuclear receptors, such as the pregnane X receptor. However, this induction of CYP3A4 has not yet been investigated in humans. Thus, the aim of the study was to determine the variability of the CYP3A4 phenotype in regard to increased concentrations of PCBs and other persistent organohalogen pollutants (POPs) in healthy Faroese adults. In 310 randomly selected Faroese residents aged 18-60 years, the CYP3A4 activity was determined based on the urinary 6β-hydroxycortisol/cortisol (6β-OHC/FC) ratio. POP exposures were assessed by measuring their concentrations in serum lipid. The results showed a unimodal distribution of the 6β-OHC/FC ratio with values ranging from 0.58 to 27.38. Women had a slightly higher 6β-OHC/FC ratio than men (p = 0.07). Confounder-adjusted multiple regression analysis showed significant associations between 6β-OHC/FC ratios and ΣPCB, PCB-TEQ and p,p'-DDE, o,p'-DDT and HCB, respectively, but the associations were statistically significant for men only
17. Interacting influence of potassium and polychlorinated biphenyl on cortisol and aldosterone biosynthesis
International Nuclear Information System (INIS)
Li, L.-A.; Lin, Tsu-Chun Emma
2007-01-01
Giving human adrenocortical H295R cells 14 mM KCl for 24 h significantly induced not only aldosterone biosynthesis but also cortisol biosynthesis. Pre-treating the cells with polychlorinated biphenyl 126 (PCB126) further increased potassium-induced aldosterone and cortisol productions in a dose-dependent manner, but all examined concentrations of PCB126 had little effect on the yields of precursor steroids progesterone and 17-OH-progesterone. Subsequent examinations revealed that CYP11B1 and CYP11B2 genes, responsible for the respective final steps of the cortisol and aldosterone biosynthetic pathways, exhibited increased responsiveness to PCB126 under high potassium. While 10 -5 M PCB126 was needed to induce a significant increase in the basal mRNA abundance of either gene, PCB126 could enhance potassium-induced mRNA expression of CYP11B1 at 10 -7 M and CYP11B2 at 10 -9 M. Actually, potassium and PCB126 synergistically upregulated mRNA expression of both genes. Potassium raised the transcriptional rates of CYP11B1 and CYP11B2 probably through a conserved Ad5 cis-element, whereas PCB126 appeared to regulate these two genes at the post-transcriptional level. Positive potassium-PCB126 synergism was also detected in CYP11B2 enzyme activity estimated by aldosterone/progesterone ratio. In contrast, potassium and PCB126 increased CYP11B1 enzyme activity or cortisol/17-OH-progesterone ratio additively. Moreover, potassium improved the time effect of PCB126 on gene expression and enzyme activity of CYP11B2, but not the PCB126 time response of CYP11B1. These data demonstrated that potassium differentially enhanced the potency of PCB126 to induce CYP11B1- and CYP11B2-mediated steroidogenesis
18. Chronic treatment with polychlorinated biphenyls (PCB) during pregnancy and lactation in the rat
International Nuclear Information System (INIS)
Colciago, A.; Casati, L.; Mornati, O.; Vergoni, A.V.; Santagostino, A.; Celotti, F.; Negri-Cesi, P.
2009-01-01
The gender-specific expression pattern of aromatase and 5alpha-reductases (5alpha-R) during brain development provides neurons the right amount of estradiol and DHT to induce a dimorphic organization of the structure. Polychlorinated biphenyls (PCBs) are endocrine disruptive pollutants; exposure to PCBs through placental transfer and breast-feeding may adversely affect the organizational action of sex steroid, resulting in long-term alteration of reproductive neuroendocrinology. The study was aimed at: a) evaluating the hypothalamic expression of aromatase, 5alpha-R1 and 5alpha-R2 in fetuses (GD20), infant (PN12), weaning (PN21) and young adult (PN60) male and female rats exposed to PCBs during development; b) correlating these parameters with the time of testicular descent, puberty onset, estrous cyclicity and copulatory behavior; c) evaluating possible alterations of some non reproductive behaviors (locomotion, learning and memory, depression/anxiety behavior). A reconstituted mixture of four indicator congeners (PCB 126, 138, 153 and 180) was injected subcutaneously to dams at the dose of 10 mg/kg daily from GD15 to GD19 and then twice a week till weanling. The results indicated that developmental PCB exposure produced important changes in the dimorphic hypothalamic expression of both aromatase and the 5alpha-Rs, which were still evident in adult animals. We observed that female puberty onset occurs earlier than in control animals without cycle irregularity, while testicular descent in males was delayed. A slight but significant impairment of sexual behavior and an important alteration in memory retention were also noted specifically in males. We conclude that PCBs might affect the dimorphic neuroendocrine control of reproductive system and of other neurobiological processes.
19. Environmental life-cycle comparisons of two polychlorinated biphenyl remediation technologies: incineration and base catalyzed decomposition.
Science.gov (United States)
Hu, Xintao; Zhu, Jianxin; Ding, Qiong
2011-07-15
Remediation action is critical for the management of polychlorinated biphenyl (PCB) contaminated sites. Dozens of remediation technologies developed internationally could be divided in two general categories incineration and non-incineration. In this paper, life cycle assessment (LCA) was carried out to study the environmental impacts of these two kinds of remediation technologies in selected PCB contaminated sites, where Infrared High Temperature Incineration (IHTI) and Base Catalyzed Decomposition (BCD) were selected as representatives of incineration and non-incineration. A combined midpoint/damage approach was adopted by using SimaPro 7.2 and IMPACTA2002+ to assess the human toxicity, ecotoxicity, climate change impact, and resource consumption from the five subsystems of IHTI and BCD technologies, respectively. It was found that the major environmental impacts through the whole lifecycle arose from energy consumption in both IHTI and BCD processes. For IHTI, primary and secondary combustion subsystem contributes more than 50% of midpoint impacts concerning with carcinogens, respiratory inorganics, respiratory organics, terrestrial ecotoxity, terrestrial acidification/eutrophication and global warming. In BCD process, the rotary kiln reactor subsystem presents the highest contribution to almost all the midpoint impacts including global warming, non-renewable energy, non-carcinogens, terrestrial ecotoxity and respiratory inorganics. In the view of midpoint impacts, the characterization values for global warming from IHTI and BCD were about 432.35 and 38.5 kg CO(2)-eq per ton PCB-containing soils, respectively. LCA results showed that the single score of BCD environmental impact was 1468.97 Pt while IHTI's score is 2785.15 Pt, which indicates BCD potentially has a lower environmental impact than IHTI technology in the PCB contaminated soil remediation process. Copyright © 2011 Elsevier B.V. All rights reserved.
20. Polychlorinated biphenyl serum levels in subjects with hepatocellular carcinoma as compared with the general population
Directory of Open Access Journals (Sweden)
Claudia Zani
2014-11-01
Full Text Available Background. Polychlorinated biphenyls (PCBs have been recognized as human carcinogens and cause liver cancer in animal experimental studies. However, no study investigated their association with hepatocellular carcinoma (HCC so far. This study aimed to evaluate the serum PCB concentration in HCC patients and in healthy subjects of the general population living in Brescia, North Italy, a highly industrialized area with heavy PCB environmental pollution due to the presence of a PCB producing factory. Methods. Lipid-adjusted PCB concentrations, computed as the sum of 24 congeners, were measured in the serum of 101 HCC patients and in 101 healthy subjects of the same age and gender.Results. Hepatitis B and C virus infection and history of heavy alcohol intake were found, alone and combined, in 87% of HCC patients. No difference was found in PCB serum concentration of HCC patients with and without, and according to, the major risk factors for liver disease. No significant difference was observed in serum total PCB concentration between HCC patients (median: 1081; range: 287.0-3182.0 ng/g lipid and healthy subjects (median: 1199.3; range: 225.7-22825 ng/g lipid. PCB congeners 118, 138, 153, 156, 180 and 194 were the only ones found over the detection limit in at least 30% of HCC patients. The serum level of PCB 118, but not that of other congeners, was higher in HCC patients than in healthy subjects.Conclusion. These findings do not support the hypothesis that PCBs play an important role in HCC development, although a contribution by some specific congeners cannot be ruled out.
1. Riparian spiders as sentinels of polychlorinated biphenyl contamination across heterogeneous aquatic ecosystems
Science.gov (United States)
Kraus, Johanna M.; Gibson, Polly P.; Walters, David M.; Mills, Marc A.
2017-01-01
Riparian spiders are being used increasingly to track spatial patterns of contaminants in and fluxing from aquatic ecosystems.However, our understanding of the circumstances under which spiders are effective sentinels of aquatic pollution is limited. The present study tests the hypothesis that riparian spiders may be effectively used to track spatial patterns of sediment pollution by polychlorinated biphenyls (PCBs) in aquatic ecosystems with high habitat heterogeneity. The spatial pattern of ΣPCB concentrations in 2 common families of riparian spiders sampled in 2011 to 2013 generally tracked spatial variation in sediment ΣPCBs across all sites within the Manistique River Great Lakes Area of Concern (AOC), a rivermouth ecosystem located on the south shore of the Upper Peninsula, Manistique (MI,USA) that includes harbor, river, backwater, and lake habitats. Sediment ΣPCB concentrations normalized for total organic carbon explained 41% of the variation in lipid-normalized spider ΣPCB concentrations across 11 sites. Furthermore, 2 common riparian spider taxa (Araneidae and Tetragnathidae) were highly correlated (r2> 0.78) and had similar mean ΣPCB concentrations when averaged acrossall years. The results indicate that riparian spiders may be useful sentinels of relative PCB availability to aquatic and riparian food webs in heterogeneous aquatic ecosystems like rivermouths where habitat and contaminant variability may make the use of aquatic taxa lesseffective. Furthermore, the present approach appears robust to heterogeneity in shoreline development and riparian vegetation that support different families of large web-building spiders. Environ Toxicol Chem 2016;9999:1–9. Published 2016 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.
2. Paddy field – A natural sequential anaerobic–aerobic bioreactor for polychlorinated biphenyls transformation
International Nuclear Information System (INIS)
Chen, Chen; Yu, Chunna; Shen, Chaofeng; Tang, Xianjin; Qin, Zhihui; Yang, Kai; Hashmi, Muhammad Zaffar; Huang, Ronglang; Shi, Huixiang
2014-01-01
3. Progressive risk assessment of polychlorinated biphenyls through a Total Diet Study in the Korean population
International Nuclear Information System (INIS)
Shin, Eun-su; Nguyen, Khanh-Hoang; Kim, Jongchul; Kim, Cho-il; Chang, Yoon-Seok
2015-01-01
Human exposure to polychlorinated biphenyls (PCBs) from foods was investigated through a Total Diet Study (TDS) for the first time in Korea. A representative food list was developed from food intake data. Non-selected foods were also included in the TDS through the mapping process to anticipate practical risk assessment. For better representativeness, data (2008–2011) from the Korea National Health and Nutrition Examination Survey (KNHANES) were combined with the TDS data set. And also, we estimated the dietary exposure to PCBs from various food items using a ‘best-fit’ mapping process and assessed the differences in PCB exposures by sex and age. In this study, we examined total PCBs (62 congeners) including dioxin-like PCBs (DL-PCBs) and indicator PCBs, which are congeners that are mainly detected in various environmental matrices. The average dietary exposure (3.94 ng/kg body weight/day) that was estimated through food intake was 19.7% of the World Health Organization (WHO) recommendation. - Highlights: • A total of 282 samples, composed of the most consumed foodstuffs in Korea, were analysed and shown in detail. • The contamination status of total PCBs in food was assessed, through their various condition on cooking methods. • The dietary intakes of PCBs in various food groups were estimated in different region, gender and age groups. • The improved and systematic food selection process was applied such as ‘mapping process’. - This study is to ensure food safety through total analysis of PCBs with the improved risk assessment method.
4. Polychlorinated biphenyls exposure-induced insulin resistance is mediated by lipid droplet enlargement through Fsp27.
Science.gov (United States)
Kim, Hye Young; Kwon, Woo Young; Kim, Yeon A; Oh, Yoo Jin; Yoo, Seung Hee; Lee, Mi Hwa; Bae, Ju Yong; Kim, Jong-Min; Yoo, Young Hyun
2017-06-01
5. Polychlorinated biphenyls in two salt marsh sediments of the Venice Lagoon.
Science.gov (United States)
Mugnai, Cristian; Giuliani, Silvia; Bellucci, Luca G; Carraro, Claudio; Favotto, Maurizio; Frignani, Mauro
2011-10-01
Polychlorinated biphenyls (PCBs) were measured in two dated salt marsh cores of the Venice Lagoon to assess their input chronology and to evaluate the importance of atmospheric deposition as a source. Sampling sites were chosen in order to evidence the differences between areas located leeward and windward with respect to inputs originating in both the city of Venice and the industrial area. Concentrations of PCB indicators (0.13-15.6 ng g⁻¹) increased gradually from the 1930s, reached maxima from the 1950s to the late 1970s, and then decreased. PCB loadings to marshes are driven by both the atmospheric deposition and the resuspension of subtidal sediments, this latter being more important for heavier congeners. The downwind marsh recorded higher fluxes (0.06-9.72 ng cm⁻² year⁻¹) than the upwind one (0.01-0.53 ng cm⁻² year⁻¹). Recent fluxes are rather consistent with bulk deposition measurements. A higher contribution of CB-101 and CB-118 was detected in the intermediate layers of the downwind site, suggesting a different PCB source for the corresponding time interval. In the other marsh, PCBs showed a rather constant composition at all levels (mostly CB-153, CB-138 and CB-180), accounting for a regional influence. Deep layers showed an enrichment of higher chlorinated congeners at both sites, whereas recent samples conserve the patterns typical of surficial and subsurficial subtidal sediments. The scientific approach adopted in this research can be considered as a sort of methodological procedure for the determination of fluxes and pathways of PCBs through the study of marsh cores.
6. The levels of polychlorinated biphenyls in 1,4-dichlorobenzene mothballs
Energy Technology Data Exchange (ETDEWEB)
Liu, Wenbin; Zheng, Minghui; Xing, Ying; Wang, Dongshen; Zhao, Xingru; Gao, Lirong [Chinese Academy of Sciences, Beijing (China). Key laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences
2004-09-15
The chemical 1,4-dichlorobenzene (p-DCB), also called paramoth, is one of the chemicals commonly used to make mothballs. For the more than 20 years, p-DCB has been used principally (35-55% of all uses) as a space deodorant for toilets and refuse containers, and as a fumigant for control of moths, molds, and mildews. The process of production of p-DCB currently used by industry is direct chlorination of benzene or chlorobenzene in the presence of a Friedel-Crafts catalyst (typically FeCl{sub 3}), and the pure products of p-DCB are obtained by distillation and crystallization from the mixture of polychlorinated benzenes. This process is similar to that of production of PCBs which were manufactured commercially by the progressive chlorination of biphenyl in the presence of a suitable catalyst, e.g., iron chloride. However, few studies on the formation of PCBs from chlorobenzenes have been published. Buser reported significant quantities of PCDFs and a small amount of PCDDs, PCBs, and chlorophenols were formed in the pyrolysis of chlorobenzenes at 620 C. Peng-Yan Liu et al. revealed that lower chlorinated benzenes produce more PCBs than higher ones. Nevertheless, prior to this study, no reports on PCBs in p-DCB and the restriction of PCBs in p-DCB products have been found. In this paper, the occurrence and distribution of dioxin-like PCBs and total PCBs in some commercial p-DCB mothballs are investigated. Except of the toxic of p-DCB, the low concentration of PCBs in p-DCB mothballs should not be negligible.
7. Biphenyl liquid crystalline epoxy resin as a low-shrinkage resin-based dental restorative nanocomposite.
Science.gov (United States)
Hsu, Sheng-Hao; Chen, Rung-Shu; Chang, Yuan-Ling; Chen, Min-Huey; Cheng, Kuo-Chung; Su, Wei-Fang
2012-11-01
Low-shrinkage resin-based photocurable liquid crystalline epoxy nanocomposite has been investigated with regard to its application as a dental restoration material. The nanocomposite consists of an organic matrix and an inorganic reinforcing filler. The organic matrix is made of liquid crystalline biphenyl epoxy resin (BP), an epoxy resin consisting of cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (ECH), the photoinitiator 4-octylphenyl phenyliodonium hexafluoroantimonate and the photosensitizer champhorquinone. The inorganic filler is silica nanoparticles (∼70-100 nm). The nanoparticles were modified by an epoxy silane of γ-glycidoxypropyltrimethoxysilane to be compatible with the organic matrix and to chemically bond with the organic matrix after photo curing. By incorporating the BP liquid crystalline (LC) epoxy resin into conventional ECH epoxy resin, the nanocomposite has improved hardness, flexural modulus, water absorption and coefficient of thermal expansion. Although the incorporation of silica filler may dilute the reinforcing effect of crystalline BP, a high silica filler content (∼42 vol.%) was found to increase the physical and chemical properties of the nanocomposite due to the formation of unique microstructures. The microstructure of nanoparticle embedded layers was observed in the nanocomposite using scanning and transmission electron microscopy. This unique microstructure indicates that the crystalline BP and nanoparticles support each other and result in outstanding mechanical properties. The crystalline BP in the LC epoxy resin-based nanocomposite was partially melted during exothermic photopolymerization, and the resin expanded via an order-to-disorder transition. Thus, the post-gelation shrinkage of the LC epoxy resin-based nanocomposite is greatly reduced, ∼50.6% less than in commercialized methacrylate resin-based composites. This LC epoxy nanocomposite demonstrates good physical and chemical properties and good biocompatibility
8. Sources, emissions, and fate of polybrominated diphenyl ethers and polychlorinated biphenyls indoors in Toronto, Canada.
Science.gov (United States)
Zhang, Xianming; Diamond, Miriam L; Robson, Matthew; Harrad, Stuart
2011-04-15
Indoor air concentrations of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) measured in 20 locations in Toronto ranged 0.008-16 ng·m(-3) (median 0.071 ng·m(-3)) and 0.8-130.5 ng·m(-3) (median 8.5 ng·m(-3)), respectively. PBDE and PCB air concentrations in homes tended to be lower than that in offices. Principal component analysis of congener profiles suggested that electrical equipment was the main source of PBDEs in locations with higher concentrations, whereas PUF furniture and carpets were likely sources to locations with lower concentrations. PCB profiles in indoor air were similar to Aroclors 1248, 1232, and 1242 and some exterior building sealant profiles. Individual PBDE and PCB congener concentrations in air were positively correlated with colocated dust concentrations, but total PBDE and total PCB concentrations in these two media were not correlated. Equilibrium partitioning between air and dust was further examined using log-transformed dust/air concentration ratios for which lower brominated PBDEs and all PCBs were correlated with K(OA). This was not the case for higher brominated BDEs for which the measured ratios fell below those based on K(OA) suggesting the air-dust partitioning process could be kinetically limited. Total emissions of PBDEs and PCBs to one intensively studied office were estimated at 87-550 ng·h(-1) and 280-5870 ng·h(-1), respectively, using the Multimedia Indoor Model of Zhang et al. Depending on the air exchange rate, up to 90% of total losses from the office could be to outdoors by means of ventilation. These results support the hypotheses that dominant sources of PBDEs differ according to location and that indoor concentrations and hence emissions contribute to outdoor concentrations due to higher indoor than outdoor concentrations along with estimates of losses via ventilation.
9. Modeling Population-Level Consequences of Polychlorinated Biphenyl Exposure in East Greenland Polar Bears.
Science.gov (United States)
Pavlova, Viola; Grimm, Volker; Dietz, Rune; Sonne, Christian; Vorkamp, Katrin; Rigét, Frank F; Letcher, Robert J; Gustavson, Kim; Desforges, Jean-Pierre; Nabe-Nielsen, Jacob
2016-01-01
Polychlorinated biphenyls (PCBs) can cause endocrine disruption, cancer, immunosuppression, or reproductive failure in animals. We used an individual-based model to explore whether and how PCB-associated reproductive failure could affect the dynamics of a hypothetical polar bear (Ursus maritimus) population exposed to PCBs to the same degree as the East Greenland subpopulation. Dose-response data from experimental studies on a surrogate species, the mink (Mustela vision), were used in the absence of similar data for polar bears. Two alternative types of reproductive failure in relation to maternal sum-PCB concentrations were considered: increased abortion rate and increased cub mortality. We found that the quantitative impact of PCB-induced reproductive failure on population growth rate depended largely on the actual type of reproductive failure involved. Critical potencies of the dose-response relationship for decreasing the population growth rate were established for both modeled types of reproductive failure. Comparing the model predictions of the age-dependent trend of sum-PCBs concentrations in females with actual field measurements from East Greenland indicated that it was unlikely that PCB exposure caused a high incidence of abortions in the subpopulation. However, on the basis of this analysis, it could not be excluded that PCB exposure contributes to higher cub mortality. Our results highlight the necessity for further research on the possible influence of PCBs on polar bear reproduction regarding their physiological pathway. This includes determining the exact cause of reproductive failure, i.e., in utero exposure versus lactational exposure of offspring; the timing of offspring death; and establishing the most relevant reference metrics for the dose-response relationship.
10. Riparian spiders as sentinels of polychlorinated biphenyl contamination across heterogeneous aquatic ecosystems.
Science.gov (United States)
Kraus, Johanna M; Gibson, Polly P; Walters, David M; Mills, Marc A
2017-05-01
11. Structural insights into the metabolism of 2-chlorodibenzofuran by an evolved biphenyl dioxygenase
Energy Technology Data Exchange (ETDEWEB)
Kumar, Pravindra [Department of Biological Sciences and Center for Cancer Research, Purdue University, West Lafayette, IN 47907 (United States); Department of Biotechnology, Indian Institute of Technology, Roorkee 247667 (India); Mohammadi, Mahmood [Institut National de la Recherche Scientifique (INRS-Institut Armand-Frappier), Laval, QC, Canada H7V 1B7 (Canada); Dhindwal, Sonali [Department of Biotechnology, Indian Institute of Technology, Roorkee 247667 (India); Pham, Thi Thanh My [Institut National de la Recherche Scientifique (INRS-Institut Armand-Frappier), Laval, QC, Canada H7V 1B7 (Canada); Bolin, Jeffrey T. [Department of Biological Sciences and Center for Cancer Research, Purdue University, West Lafayette, IN 47907 (United States); Sylvestre, Michel, E-mail: Michel.Sylvestre@iaf.inrs.ca [Institut National de la Recherche Scientifique (INRS-Institut Armand-Frappier), Laval, QC, Canada H7V 1B7 (Canada)
2012-05-18
Highlights: Black-Right-Pointing-Pointer Regiospecificity of BphAE{sub RR41} toward dibenzofuran and 2-chlorodibenzofuran differs. Black-Right-Pointing-Pointer We compared the structures of the substrate-bound forms of the enzyme with both substrates. Black-Right-Pointing-Pointer Dibenzofuran is compelled to move during the catalytic reaction. Black-Right-Pointing-Pointer Ser283 contact with 2-chlorodibenzofuran helps prevent substrate movement during the reaction. -- Abstract: The biphenyl dioxygenase of Burkholderia xenovorans LB400 (BphAE{sub LB400}) is a Rieske-type oxygenase that catalyzes the stereospecific oxygenation of many heterocyclic aromatics including dibenzofuran. In a previous work, we evolved BphAE{sub LB400} and obtained BphAE{sub RR41}. This variant metabolizes dibenzofuran and 2-chlorodibenzofuran more efficiently than BphAE{sub LB400}. However, the regiospecificity of BphAE{sub RR41} toward these substrates differs. Dibenzofuran is metabolized principally through a lateral dioxygenation whereas 2-chlorodibenzofuran is metabolized principally through an angular dioxygenation. In order to explain this difference, we examined the crystal structures of both substrate-bound forms of BphAE{sub RR41} obtained under anaerobic conditions. This structure analysis, in combination with biochemical data for a Ser283Gly mutant provided evidences that the substrate is compelled to move after oxygen-binding in BphAE{sub RR41}:dibenzofuran. In BphAE{sub RR41}:2-chlorodibenzofuran, the chlorine atom is close to the side chain of Ser283. This contact is missing in the BphAE{sub RR41}:dibenzofuran, and strong enough in the BphAE{sub RR41}:2-chlorodibenzofuran to help prevent substrate movement during the catalytic reaction.
12. Structural insights into the metabolism of 2-chlorodibenzofuran by an evolved biphenyl dioxygenase
International Nuclear Information System (INIS)
Kumar, Pravindra; Mohammadi, Mahmood; Dhindwal, Sonali; Pham, Thi Thanh My; Bolin, Jeffrey T.; Sylvestre, Michel
2012-01-01
Highlights: ► Regiospecificity of BphAE RR41 toward dibenzofuran and 2-chlorodibenzofuran differs. ► We compared the structures of the substrate-bound forms of the enzyme with both substrates. ► Dibenzofuran is compelled to move during the catalytic reaction. ► Ser283 contact with 2-chlorodibenzofuran helps prevent substrate movement during the reaction. -- Abstract: The biphenyl dioxygenase of Burkholderia xenovorans LB400 (BphAE LB400 ) is a Rieske-type oxygenase that catalyzes the stereospecific oxygenation of many heterocyclic aromatics including dibenzofuran. In a previous work, we evolved BphAE LB400 and obtained BphAE RR41 . This variant metabolizes dibenzofuran and 2-chlorodibenzofuran more efficiently than BphAE LB400 . However, the regiospecificity of BphAE RR41 toward these substrates differs. Dibenzofuran is metabolized principally through a lateral dioxygenation whereas 2-chlorodibenzofuran is metabolized principally through an angular dioxygenation. In order to explain this difference, we examined the crystal structures of both substrate-bound forms of BphAE RR41 obtained under anaerobic conditions. This structure analysis, in combination with biochemical data for a Ser283Gly mutant provided evidences that the substrate is compelled to move after oxygen-binding in BphAE RR41 :dibenzofuran. In BphAE RR41 :2-chlorodibenzofuran, the chlorine atom is close to the side chain of Ser283. This contact is missing in the BphAE RR41 :dibenzofuran, and strong enough in the BphAE RR41 :2-chlorodibenzofuran to help prevent substrate movement during the catalytic reaction.
13. Determination of plasma concentrations of organochlorine pesticides and polychlorinated biphenyls in pet cats and dogs.
Science.gov (United States)
Yavuz, Oguzhan; Arslan, Handan Hilal; Esin, Cagatay; Das, Yavuz Kursad; Aksoy, Abdurrahman
2018-01-01
The aim of this study was the determination of plasma concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in cats and dogs and evaluation of their prevalence and possible effects. The concentrations of nine OCPs, such as α-hexachlorocyclohexane (HCH), β-HCH, γ-HCH, hexachlorobenzene (HCB), aldrin, 2,4'-dichlorodiphenyltrichloroethane (2,4'-DDT), 4,4'-DDT, 2,4'-dichlorodiphenyldichloroethylene (2,4'-DDE) and 4,4'-DDE and 16 PCBs (PCB-28, -52, -70, -74, -81, -99, -101, -118, -138, -153, -156, -170, -180, -183, -187 and -208) were evaluated in the plasma samples of pet cats ( n = 15) and dogs ( n = 21). The concentrations of OCPs ranged from 1.12 ng g -1 lipid weight (lw) to 7.65 ng g -1 lw in cats and from 1.25 ng g -1 lw to 6.79 ng g -1 lw in dogs. In addition, mean PCB levels were 0.58-5.66 and 0.52-6.62 ng g -1 lw in cats and dogs, respectively. β-HCH, γ-HCH and PCB-138 levels were significantly higher in dogs ( p < 0.05). As far as could be determined, OCPs and PCBs were detected in the plasma samples of domestic cats and dogs in Turkey for the first time. Their concentrations were similar to those reported in earlier studies abroad. However, in contrast to other research, the levels of some OCPs were higher in dogs than in cats. It is concluded that, because of their high prevalence and potential health effects in animals and humans, OCP and PCB levels should be monitored systematically in domestic cats and dogs.
14. NUMERICAL MODELING OF THE FIELDS OF POLYCHLORINATED BIPHENYLS IN THE BLACK SEA
Directory of Open Access Journals (Sweden)
Vitaly Ivanov
2013-01-01
Full Text Available A mathematical three-dimensional model was developed by combining a physically complete block of circulation with modules of transport and transformation of detritus and polychlorinated biphenyls (PCBs. This z-coordinate model has a horizontal resolution of 5 × 5 km, 45 vertical levels, and a step of 5 minutes. The model considers gravitational sedimentation and decomposition of detritus, as well as its deposition and erosion on the bottom. To calculate the transport and transformation of PCBs in the Sea, the model uses three state variables: the concentration of PCBs in solution, in detritus, and in the upper layer of sediment. It also considers sorption, desorption, and reversible flows of PCBs at the bottom.A 20-day model calculation was performed to simulate a potential accidental release of PCBs in the area of the Danube Delta in spring. The PCBs advection flows dominated and were comparable to the adsorption/desorption flows, while the diffusion fluxes were infinitesimal. Up to 20% of discharged PCBs were adsorbed by detritus in the first two days after the accident. There was a gradual accumulation of PCBs on the bottom; 16 days after the accident, 18% of the PCBs were bound to the sediments. The PCBs transport on detritus serves as a natural buffer mechanism that weakens the spread of PCBs in the sea. The paper analyzes the dynamics of PCB fields formed as a result of the application of an artificial active sorbent to minimize adverse effects on the ecosystem. An end-user oriented software application was developed; it allows forecasting the dynamics of potential releases of PCBs and planning counter-measures. A user-friendly interface allows tracking the field, visualizing the distribution of PCBs in the water column and sediments, and displaying the balance between dissolved and suspended phases.Key words: multidisciplinary model, PCB transport, adsorption, desorption, sediments
15. Occurrence and air-soil exchange of organochlorine pesticides and polychlorinated biphenyls at a CAWNET background site in central China: Implications for influencing factors and fate.
Science.gov (United States)
Zhan, Lingxi; Lin, Tian; Wang, Zuwu; Cheng, Zhineng; Zhang, Gan; Lyu, Xiaopu; Cheng, Hairong
2017-11-01
Ambient air and soil samples were collected between March 2012 and March 2013 at Jinsha, a regional background site in central China, to measure the concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). The average concentrations of total OCPs and total PCBs were 191 ± 107 and 39.4 ± 27.1 pg/m 3 in air (gaseous and particulate phase) and 0.585 ± 0.437 and 0.083 ± 0.039 ng/g in soil, respectively. The higher concentrations of p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) and p,p'-DDT/p,p'-DDE ratios in the soil indicated recent p,p'-DDT input to the soil. A strong positive temperature dependence and average fugacity fraction value > 0.5 were observed for p,p'-DDT, suggesting that volatilization of residual DDT in the soil was the main influencing factor on atmospheric p,p'-DDT. Highly average fugacity fractions (>0.7) of trans-chlordane (TC) and cis-chlordane (CC) and high TC/CC ratios both in the soil and atmosphere suggested fresh inputs. Higher gaseous concentrations of hexachlorobenzene (HCB) were observed in winter and negative temperature dependence was directly attributed to the surrounding ongoing source (e.g. fuel consuming activities), especially in winter. Overall, most targeted OCPs and PCBs were influenced by long-range transport, and fugacity fraction values indicated highly volatile compounds (e.g. α-hexachlorocyclohexane (α-HCH) and lower chlorinated PCBs) were volatilized and low volatility compounds (e.g. p,p'-DDE and higher chlorinated PCBs) were deposited at the air-soil interface. Knowing the source and sink of OCPs and PCBs can help to control their pollution in this area and provide a reference for other studies. Copyright © 2017 Elsevier Ltd. All rights reserved.
16. Temporal and spatial variation of polychlorinated biphenyls (PCBs) contamination in environmental compartments of highly polluted area in Central Russia.
Science.gov (United States)
Malina, Natalia; Mazlova, Elena A
2017-10-01
This study highlights the fact that serious contamination from polychlorinated biphenyls (PCBs) still exists in Serpukhov City (Russia). The research help to determine the temporal (16- and 24-year periods) and spatial PCBs distribution in the environmental compartments of the studied region. Samples of soil, sediments, water and plants were analysed in order to establish their contamination levels. The most recent data on the Serpukhov City's soil contamination showed that the PCBs concentrations varies from 0.0009 to 1169 mg/kg depending on the sampling point and the distance from the pollution source. The temporal trends of the contamination distribution with the soil depth showed contamination migration in the upper soil layers of the highly polluted site. The high level of water pollution (11.5 μg/L) in the proximity to the contamination source and the sediments contamination (0.098-119 mg/kg) were determined, as well as the water migration pathways of the PCBs that were prevalent in the studied region. The PCB congener group (by the level of chlorination) analysis showed that heptachlorinated biphenyls were only found in the soils in close proximity to the contamination place, while biphenyls with Cl ≤ 6 were found in the soil samples downstream of the condenser plant and with Cl ≤ 5 in the soil samples upstream of the plant. The plant uptake of PCBs, even on the extremely contaminated site, was shown. In turn, this research present new knowledge necessary for the development of a contaminated territory remediation strategy. Copyright © 2017 Elsevier Ltd. All rights reserved.
17. Compounding around the world.
Science.gov (United States)
Vail, Jane
2008-01-01
Pharmaceutical compounding is universal in its prevalence. Variations in disease patterns, culture, and tradition; the role of government in health care; and the availability of essential equipment and required agents shape a compounding profile unique to each country worldwide. In the following reflections, pharmacists form Argentina, Belgium, Colombia, Germany, Puerto Rico, Spain, and the United States describe their experiences in the compounding setting unique to their practice and their nation. The unifying theme in their comments is the dedication of each contributor to enabling recovery and ensuring the good health of his or her clients.
18. Studies on air and water pollution. I. Polychlorinated biphenyls and benzopyrene status report July 1977 - June 1978
International Nuclear Information System (INIS)
Santos, F.L.; Cunanan, S.A.
1979-01-01
An analytical methodology developed for trace amounts of polychlorinated biphenyls (PCB's) in water was described. The water sample was extracted with hexane and the extract passes through a florisil column. The cleaned extract was concentrated and then analyzed by gas chromatography using an electron capture detector. The methodology has an efficiency of 85% recovery for PCB spiked at a concentration level of 1 ppm. Minimum detection limit obtained was 0.5 ppm PCB in water. A total of 27 water samples were collected and analyzed during the period January - June 1978. No PCB's were detected in the samples. (author)
19. Use of RIA determination of polychlorinated biphenyls (PCB) in prevention of their penetration into the food chain
International Nuclear Information System (INIS)
Zajic, J.; Sisak, M.; Diblikova, I.; Bendova, J.; Matouskova, O.; Hruska, K.
1991-01-01
Radiomimmunological determination of polychlorinated biphenyls in milk can serve in the screening of milk cows and condemnation of contaminated individuals. The source of PCB contamination can be ascertained by checking the routes the milk is passing. The RIA method was also employed to examine bioptically taken cow fat. The method was also applied to human milk in a maternity hospital in Brno; out of 55 samples, none exhibited a PCB concentration higher than 1.4 mg/kg. (M.D.). 3 tabs., 4 figs
20. Comparison of solvent extraction and solid-phase extraction for the determination of polychlorinated biphenyls in transformer oil.
Science.gov (United States)
Mahindrakar, A N; Chandra, S; Shinde, L P
2014-01-01
Solid-phase extraction (SPE) of nine polychlorinated biphenyls (PCBs) from transformer oil samples was evaluated using octadecyl (CI8)-bonded porous silica. The efficiency of SPE of these PCBs was compared with those obtained by solvent extraction with DMSO and hexane. Average recoveries exceeding 95% for these PCBs were obtained via the SPE method using small cartridges containing 100mg of 40 pm CI8-bonded porous silica. The average recovery by solvent extraction with DMSO and hexane exceeded 83%. It was concluded that the recoveries and precision for the solvent extraction of PCBs were poorer than those for the SPE. Copyright © 2013 Elsevier Ltd. All rights reserved.
1. OXIDATION OF POLYCHLORINATED BIPHENYLS BY LIVER TISSUE SLICES FROM PHENOBARBITAL-PRETREATED MICE IS CONGENER-SPECIFIC AND ATROPSELECTIVE
OpenAIRE
Wu, Xianai; Duffel, Michael; Lehmler, Hans-Joachim
2013-01-01
Mouse models are powerful tools to study the developmental neurotoxicity of polychlorinated biphenyls (PCBs); however, studies of the oxidation of chiral PCB congeners to potentially neurotoxic hydroxylated metabolites (OH-PCBs) in mice have not been reported. Here we investigate the atropselective oxidation of chiral PCB 91 (2,2',3,4',6-pentachlorobiphenyl), PCB 95 (2,2',3,5',6-pentachlorobiphenyl), PCB 132 (2,2',3,3',4,6'-hexachlorobiphenyl), PCB 136 (2,2',3,3',6,6'-hexachlorobiphenyl) and ...
2. Mucinous gastric hyperplasia in a colony of rhesus monkeys (Macaca mulatta) induced by polychlorinated biphenyl (Aroclor 1254)
Energy Technology Data Exchange (ETDEWEB)
Geistfeld, J.G.; Bond, M.G.; Bullock, B.C.; Varian, M.C.
1982-02-01
Since 1971, 45 of 259 male rhesus monkeys housed in a primate building have died of a chronic and progressive disease characterized by diarrhea, dehydration, weakness, gingivitis, emaciation, and alopecia. The principal necropsy finding in these monkeys, and in eight others killed for experimental purposes, was hypertrophic and hyperplastic mucinous gastropathy involving both the mucosa and submucosa. The toxic agent involved was identified as the polychlorinated biphenyl (PCB), Aroclor 1254. The suspected source of the toxic agent was a concrete sealer used during building construction.
3. The concentrations of radionuclides, heavy metals, and poloychlorinated biphenyls in field mice collected from regional background areas. Revision 3
Energy Technology Data Exchange (ETDEWEB)
Fresquez, Philip R. [Los Alamos National Laboratory
2016-01-21
Field mice are effective indicators of contaminant presence. This paper reports the concentrations of various radionuclides, heavy metals, polychlorinated biphenyls, high explosives, perchlorate, and dioxin/furans in field mice (mostly deer mice) collected from regional background areas in northern New Mexico. These data, represented as the regional statistical reference level (the mean plus three standard deviations = 99% confidence level), are used to compare with data from field mice collected from areas potentially impacted by Laboratory operations, as per the Environmental Surveillance Program at Los Alamos National Laboratory.
CERN Document Server
Owens, Alan
2012-01-01
Although elemental semiconductors such as silicon and germanium are standard for energy dispersive spectroscopy in the laboratory, their use for an increasing range of applications is becoming marginalized by their physical limitations, namely the need for ancillary cooling, their modest stopping powers, and radiation intolerance. Compound semiconductors, on the other hand, encompass such a wide range of physical and electronic properties that they have become viable competitors in a number of applications. Compound Semiconductor Radiation Detectors is a consolidated source of information on all aspects of the use of compound semiconductors for radiation detection and measurement. Serious Competitors to Germanium and Silicon Radiation Detectors Wide-gap compound semiconductors offer the ability to operate in a range of hostile thermal and radiation environments while still maintaining sub-keV spectral resolution at X-ray wavelengths. Narrow-gap materials offer the potential of exceeding the spectral resolutio...
5. Hexavalent Chromium Compounds
Science.gov (United States)
Learn about chromium, exposure to which can increase your risk of lung cancer and cancer of the paranasal sinuses and nasal cavity. Hexavalent chromium compounds have been used as corrosion inhibitors in a wide variety of products and processes.
6. MEA 86 Compound data
Data.gov (United States)
U.S. Environmental Protection Agency — This data file contains the full raw parameter data for the 86 compounds tested in the developmental MEA assay, as well as Area Under the Curve (AUC) calculations...
OpenAIRE
Steffen Eller
2016-01-01
Pharmaceutical industry faces the increased demand for innovative medicines against various diseases. In this regard, the compound library in pharmaceutical industry is the most valuable asset. However, the compound distribution from the library into the screening plates is often still done manually and binds highly qualified resources to very time-consuming, tedious and error-prone tasks. To overcome these challenges, Chemspeed launched the first automated true one-to-one gravimetric "pi...
8. Phenolic Molding Compounds
Science.gov (United States)
Koizumi, Koji; Charles, Ted; de Keyser, Hendrik
Phenolic Molding Compounds continue to exhibit well balanced properties such as heat resistance, chemical resistance, dimensional stability, and creep resistance. They are widely applied in electrical, appliance, small engine, commutator, and automotive applications. As the focus of the automotive industry is weight reduction for greater fuel efficiency, phenolic molding compounds become appealing alternatives to metals. Current market volumes and trends, formulation components and its impact on properties, and a review of common manufacturing methods are presented. Molding processes as well as unique advanced techniques such as high temperature molding, live sprue, and injection/compression technique provide additional benefits in improving the performance characterisitics of phenolic molding compounds. Of special interest are descriptions of some of the latest innovations in automotive components, such as the phenolic intake manifold and valve block for dual clutch transmissions. The chapter also characterizes the most recent developments in new materials, including long glass phenolic molding compounds and carbon fiber reinforced phenolic molding compounds exhibiting a 10-20-fold increase in Charpy impact strength when compared to short fiber filled materials. The role of fatigue testing and fatigue fracture behavior presents some insight into long-term reliability and durability of glass-filled phenolic molding compounds. A section on new technology outlines the important factors to consider in modeling phenolic parts by finite element analysis and flow simulation.
9. Flame retardants, polychlorinated biphenyls and insecticides in pregnant women in the northern part of The Netherlands
Energy Technology Data Exchange (ETDEWEB)
Meijer, L.; Sauer, P. [Beatrix Childrens Hospital, University Hospital Groningen (Sweden); Weiss, J.; Bergman, A. [Stockholm Univ. (Sweden). Dept. of Environmental Chemistry; Velzen, M. van; Brouwer, A. [Free Univ., Amsterdam (Netherlands). Inst. for Environmental Studies
2004-09-15
Organohalogens (OHS) are compounds with lipophilic properties, which accumulate in the environment, wildlife and humans. Human exposure is mainly through dietary intake of animal fat. After exposure the compounds are slowly metabolised leading to accumulation, mainly in the adipose tissue. During pregnancy the compounds are transported across the placenta to the fetus. OHS have an adverse effect on human health, these adverse effects are more likely to be seen in developing fetus. In 2001 the Compare project (supported by the European Union) started with the aim to examine the exposure-effect pathways to different kinds of organohalogen compounds. Therefore a cohort was founded in which 90 pregnant women living in the northern part of the Netherlands participated, the Dutch Groningen Infant Cohort. In this cohort p,p'-DDE, PCB-153, 4OH-PCB- 107, 4OH-PCB-146, 4OH-PCB-187, PCP, BDE-47, 6OH-BDE-47, BDE-99, BDE-100, BDE-153, BDE-154 and HBCDD were determined in blood samples taken in the 20{sup th} and 35{sup th} week of pregnancy. Transplacental transfer of these compounds was determined by analyzing the cord blood samples of the infants. The infants were followed for 1 1/2 years to examine the influence of the compounds on their development. In this short paper the results of the levels of the selected OHS in pregnant women are presented.
10. Polychlorinated biphenyls and polybrominated biphenyl ethers in adipose tissue and matched serum from an E-waste recycling area (Wenling, China)
International Nuclear Information System (INIS)
Lv, Quan-Xia; Wang, Wenyue; Li, Xing-Hong; Yu, Lianlian; Zhang, Yun; Tian, Yuan
2015-01-01
To Date, the knowledge on relationship between PCBs/PBDEs exposure and thyroid hormones (THs) levels during pregnancy still needs to be extended. Meanwhile, studies on congener-specific adipose-serum ratios for PCBs/PBDEs were limited. This study reports the levels of PCBs/PBDEs in serum-adipose tissue samples (n = 64) from expectant women living surrounding e-waste recycling sites in Wenling, China. Their concentrations varied from several to hundreds of ng g −1 lipid. Maternal exposure to PCBs was associated with lower TSH during pregnancy, suggesting possible implication for maternal health and fetal development. The compound levels between the adipose tissue and matched serum samples were highly correlated (p < 0.001), generating a predicted adipose-serum partitioning relationship for individual PCB congener and PBDE congener. Molecular characteristics, such as K ow value, molecular weight and molecular volume, may play a key role in the variable partitioning of some compounds between serum and adipose tissue. - Highlights: • PCBs/PBDEs were detected in the pregnant women from Wenling, China. • Exposure from e-waste recycling activities might considerably contribute to the elevated levels. • The adipose-serum partitioning ratios for PCBs/PBDEs were predicted. • Maternal exposure to PCBs may be associated with lower TSH during pregnancy. - The congener-specific adipose-serum ratios for PCBs/PBDEs were predicted in humans, and association of PCBs/PBDEs exposure was examined with THs levels
11. Polychlorinated biphenyls and biotransformation enzymes in three species of sea turtles from the Baja California peninsula of Mexico.
Science.gov (United States)
Richardson, K L; Lopez Castro, M; Gardner, S C; Schlenk, D
2010-01-01
Concentrations of polychlorinated biphenyls (PCBs) as well as the expression patterns of cytochrome P450 (CYP) enzymes and glutathione-S-transferase (GST) activities were measured in livers of loggerhead (Caretta caretta), green (Chelonia mydas), and olive ridley (Lepidocheyls olivacea) sea turtles from the Baja California peninsula of Mexico. The mean concentrations of total PCBs were 18.1, 10.5, and 15.2 ng/g wet weight (ww) respectively for the three species and PCB 153 was the dominant congener in all samples. Total PCB concentrations were dominated by penta- and hexa-chlorinated biphenyls. The mean estimated TEQs were 42.8, 22.9, and 10.4 pg/g (ww) for loggerhead, green, and olive ridley, respectively, and more than 70% was accounted for by non-ortho PCBs. Western blots revealed the presence of hepatic microsomal proteins that cross-reacted with anti-CYP2K1 and anti-CYP3A27 antibodies but not with anti-CYP1A antibody. There were no significant differences in GST activities between species. Grouping congeners based on structure-activity relationships for CYP isoenzymes suggested limited activity of CYP1A contribution to PCB biotransformation in sea turtles. These results suggest potential accumulation of PCBs that are CYP1A substrates and provide evidence for biotransformation capacity, which differs from known animal models, highlighting the need for further studies in reptiles, particularly those threatened with extinction.
12. Selective scanning tunnelling microscope electron-induced reactions of single biphenyl molecules on a Si(100) surface.
Science.gov (United States)
Riedel, Damien; Bocquet, Marie-Laure; Lesnard, Hervé; Lastapis, Mathieu; Lorente, Nicolas; Sonnet, Philippe; Dujardin, Gérald
2009-06-03
Selective electron-induced reactions of individual biphenyl molecules adsorbed in their weakly chemisorbed configuration on a Si(100) surface are investigated by using the tip of a low-temperature (5 K) scanning tunnelling microscope (STM) as an atomic size source of electrons. Selected types of molecular reactions are produced, depending on the polarity of the surface voltage during STM excitation. At negative surface voltages, the biphenyl molecule diffuses across the surface in its weakly chemisorbed configuration. At positive surface voltages, different types of molecular reactions are activated, which involve the change of adsorption configuration from the weakly chemisorbed to the strongly chemisorbed bistable and quadristable configurations. Calculated reaction pathways of the molecular reactions on the silicon surface, using the nudge elastic band method, provide evidence that the observed selectivity as a function of the surface voltage polarity cannot be ascribed to different activation energies. These results, together with the measured threshold surface voltages and the calculated molecular electronic structures via density functional theory, suggest that the electron-induced molecular reactions are driven by selective electron detachment (oxidation) or attachment (reduction) processes.
13. Defining the sources of airborne polychlorinated biphenyls: evidence for the influence of microbially dechlorinated congeners from river sediment?
Energy Technology Data Exchange (ETDEWEB)
Chiarenzelli, J. [SUNYat Oswego, NY (United States); Bush, B.; Casey, A.; O' Keefe, P. [SUNY at Albany, School of Public Health, Rensselaer, NY (United States); Barnard, E.; Smith, B. [New York State Dept. of Health, Wadsworth Center for Laboratories and Research, Albany, NY (United States); Gilligan, E. [Syracuse Univ., Dept. of Civil an Environmental Engineering, NY (United States); Johnson, G. [Energy and Geoscience Institute, Dept, of Civil and Environmental Engineering, Salt Lake City, UT (United States)
2000-07-01
During sampling in 1993, elevated levels of polychlorinated biphenyls were discovered near three industrial facilities on the Akwesasne Mohawk Nation Reserve along the St. Lawrence River, straddling the Canadian-US. border. Volatilization of Aroclor 1248, which was used extensively at all three sites, was identified as the dominant source, augmented in a minor way by a dechlorinated source, presumably from river sediment and waters. These two sources were found to account for 80 per cent of the contamination. Further, it was established that at a small cove adjacent to an industrial landfill, summer concentrations of PCBs exceeded winter concentrations by a factor of 27. Observation showed the presence of similar congener-specific PCB patterns at all sample sites and an increase in the concentrations of chlorine to biphenyl ratios during the summer months. During the colder months PCB concentrations at all sites declined, nevertheless, PCB levels were still higher than those measured elsewhere in the Great Lakes region during the same time period. Results of this investigation suggest that atmospheric deposition from local contaminant sources can elevate concentrations in produce and vegetative matter, complicating exposure routes and bioaccumulation via modeling of food chain. 22 refs., 4 tabs. 1 fig.
14. Cucurbita spp. and Cucumis sativus enhance the dissipation of polychlorinated biphenyl congeners by stimulating soil microbial community development
International Nuclear Information System (INIS)
Qin, Hua; Brookes, Philip C.; Xu, Jianming
2014-01-01
A number of Cucurbita species have the potential to extract polychlorinated biphenyls (PCBs) from soil, but their impact on the soil microbial communities responsible for PCB degradation remains unclear. A greenhouse experiment was conducted to investigate the effect of three Cucurbita and one Cucumis species on PCB dissipation and soil microbial community structure. Compared to the unplanted control, enhanced losses of PCBs (19.5%–42.7%) were observed in all planted soils. Cucurbita pepo and Cucurbita moschata treatments were more efficient in PCB dissipation, and have similar patterns of soil phospholipid fatty acids (PLFAs) and PCB congener profiles. Cucurbita treatments tend to have higher soil microbial biomass than Cucumis. Gram-negative (G − ) bacteria were significantly correlated with PCB degradation rates (R 2 = 0.719, p − bacteria were correlated with dissipation of the penta homologue group (R 2 = 0.590, p − bacteria contributed significantly to soil PCB dissipation. • Fungi have a great potential in the dissipation of high chlorinated biphenyls. -- Cucurbita associated fungi and G − bacteria have important influence on soil PCB dissipation rate and congener profile
15. Corrective Action Investigation Plan for Corrective Action Unit 528: Polychlorinated Biphenyls Contamination, Nevada Test Site, Nevada, Rev. 0
Energy Technology Data Exchange (ETDEWEB)
2003-05-08
This Corrective Action Investigation Plan contains the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office's approach to collect the data necessary to evaluate corrective action alternatives appropriate for the closure of Corrective Action Unit (CAU) 528, Polychlorinated Biphenyls Contamination (PCBs), Nevada Test Site (NTS), Nevada, under the Federal Facility Agreement and Consent Order. Located in the southwestern portion of Area 25 on the NTS in Jackass Flats (adjacent to Test Cell C [TCC]), CAU 528 consists of Corrective Action Site 25-27-03, Polychlorinated Biphenyls Surface Contamination. Test Cell C was built to support the Nuclear Rocket Development Station (operational between 1959 and 1973) activities including conducting ground tests and static firings of nuclear engine reactors. Although CAU 528 was not considered as a direct potential source of PCBs and petroleum contamination, two potential sources of contamination have nevertheless been identified from an unknown source in concentrations that could potentially pose an unacceptable risk to human health and/or the environment. This CAU's close proximity to TCC prompted Shaw to collect surface soil samples, which have indicated the presence of PCBs extending throughout the area to the north, east, south, and even to the edge of the western boundary. Based on this information, more extensive field investigation activities are being planned, the results of which are to be used to support a defensible evaluation of corrective action alternatives in the corrective action decision document.
16. Distribution, sources, and risk assessment of polychlorinated biphenyls in surface waters and sediments of rivers in Shanghai, China
Science.gov (United States)
Wang, Xueping; Han, Jingchao; Bi, Chunjuan; Huang, Xing; Jia, Jinpu; Chen, Zhenlou
2017-06-01
The distribution, sources, and potential risks of polychlorinated biphenyl (PCB) contamination in the rivers of Shanghai, China were investigated. Fourteen PCB congeners in surface waters and sediments, which were collected from 53 sampling sites, were quantified by gas chromatography-mass spectrometer (GC-MS). The total concentrations of PCBs in the dissolved phase, in particulates, and in sediments ranged from not detected (nd) to 34.8 ng•L‒1, from 0.76 to 39.71 ng•L‒1, and from 1.46 to 46.11 ng•g-1 (dry weight, dw), respectively. The corresponding WHO toxic equivalents (TEQs) of dioxinlike polychlorinated biphenyls (dl-PCBs) ranged between nd-1135.63 pg TEQ•L-1, 0.02-605.94 pg TEQ•L-1, and 0.05-432.12 pg TEQ•g-1 dw, respectively. The penta-CBs, especially PCB 118 and PCB 105, were the dominant congeners in all samples. Principle Component Analysis (PCA) indicated that the PCBs were mainly influenced by a historical accumulation of commercial PCB products, the burning of house coal, and emissions from municipal solid waste incineration (MSWI) and secondary metallurgy industries. The center of Shanghai was significantly affected by PCB contamination, followed by the industrial parklands and suburban towns, while the farmland of Chongming Island was the least affected area. Adverse biological and health effects would be likely in the central urban areas, industrial parks, and residential towns of Shanghai.
17. Polybrominated diphenyl ethers and polychlorinated biphenyls in human adipose tissue from New York.
Science.gov (United States)
Johnson-Restrepo, Boris; Kannan, Kurunthachalam; Rapaport, David P; Rodan, Bruce D
2005-07-15
Human adipose tissue samples (n=52) collected in New York City during 2003-2004 were analyzed for the presence of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). Concentrations of PBDEs in adipose tissues ranged from 17 to 9630 ng/g, lipid wt (median: 77; mean: 399 ng/g, lipid wt; sum all di- through hexaBDE congeners). Average PBDE concentrations in human adipose tissues from New York City were 10- to 100-times greater than those reported for European countries. A concentration of 9630 ng/g, lipid wt, found in a sample of adipose tissue, is one of the highest concentrations reported to date. PBDE 47 (2,2',4,4'-tetraBDE) was the major congener detected in human tissues, followed by PBDE congeners #99 (2,2',4,4',5-penta BDE), 100 (2,2',4,4',6-pentaBDE), and 153 (2,2',4,4',5,5'-hexaBDE). A few individuals contained PBDE 153 as the predominant congener in total PBDE concentrations, suggesting alternative exposure sources, possibly occupational. Principal component analysis of PBDE congener composition in human adipose tissues revealed the presence of five clusters, each characterized by varying composition. No significant difference was found in the concentrations of PBDEs between gender. Concentrations of PBDEs were, on average, similar to those for PCBs in human adipose tissues, and substantially higher when PBDE outliers were retained. PBDE and PCB concentrations were not correlated. PBDE concentrations did not increase with increasing age of the subjects, whereas concentrations of PCBs increased with increasing age in males but not in females in this study. These results suggest differences between PBDEs and PCBs in their sources or time course of exposure and disposition. The presence of comparable or greater concentrations of PBDEs, relative to PCBs, highlights the importance of recentvoluntary and regulatory effortsto cease production of commercial penta- and octa-BDE in North America, although these efforts do not address
18. Milk transfer and neonatal uptake of coplanar polychlorinated biphenyl (PCB) congeners in mice
Energy Technology Data Exchange (ETDEWEB)
Sinjari, T. [Uppsala Univ., Dept. of Pharmaceutical Biosciences, Div. of Toxicology, Uppsala (Sweden); Klasson-Wehler, W. [Stockholm Univ., Wallenberg Lb., Environmental Chemistry, Stockholm (Sweden); Oskarsson, A. [Swedish Univ. of Agricultural Science, Dept. of Food Hygiene, Uppsala (Sweden); Darnerud, P.O. [National Food Administration, Toxicology Div., uppsala (Sweden)
1996-03-01
The selective accumulation of 3,34,3-tetrachlorobiphenyl metabolites in late gestational fetal blood and soft tissues in mice as a result of administration of different coplanar polychlorinated biphenyl (PCB) congeners, is reported elsewhere. The situation in the nursing neonate after maternal exposure to the same congeners is now studied: The {sup 14}C-labelled congeners 3,3,4,4-tetrachlorobiphenyl (IUPAC number CB-77), 3,3,4,4,5-pentachlorobiphenyl (IUPAC number CB-126), 3,34,45,5-hexachlorobiphenyl (IUPAC number CB-169) (all three non-ortho congeners) and 2,3,3,4,4`-pentachlorobiphenyl (IUPAC number CB-105) (mono-ortho congener) were injected intravenously in lactating mice at day 11 post partum. One day and four days later, milk and neonatal/maternal tissues and plasma radioactivity was monitored by liquid scintillation counting (dose: 2.0 {mu}mol (20-50 {mu}Ci)/kg body weight). In milk, CB-126, -169 and -105 showed higher levels (1450-2520 pmol/ml; one day after administration) than did CB-77 (580 pmol/ml), and in neonates, the relative whole-body levels of radioactivity were related to the levels seen in milk (probably the consequences of their metabolic persistence). The comparably high {sup 14}C-concentration found in neonatal liver (about 15,000 pmol/kg) after CB-126 administration and in plasma (880 pmol/ml) after CB-77 administration could be explained by binding to specific proteins. In general, neonatal mice had two to seven times higher plasma levels than those of their mothers. These results indicate that CB-126, -169 and -105 are transferred via milk to neonates in considerable quantity and are deposited in neonatal liver, whereas CB-77 is transferred in a comparably lower amount and accumulated in neonatal plasma. The lower {sup 14}C-levels in the NMRI mothers and offspring (about half of C57BL values in maternal and neonatal plasma), could possibly be explained by a differentiated metabolism of CB-77 in these two strains.
19. Environmental life-cycle comparisons of two polychlorinated biphenyl remediation technologies: Incineration and base catalyzed decomposition
International Nuclear Information System (INIS)
Hu Xintao; Zhu Jianxin; Ding Qiong
2011-01-01
Highlights: → We study the environmental impacts of two kinds of remediation technologies including Infrared High Temperature Incineration(IHTI) and Base Catalyzed Decomposition(BCD). → Combined midpoint/damage approaches were calculated for two technologies. → The results showed that major environmental impacts arose from energy consumption. → BCD has a lower environmental impact than IHTI in the view of single score. - Abstract: Remediation action is critical for the management of polychlorinated biphenyl (PCB) contaminated sites. Dozens of remediation technologies developed internationally could be divided in two general categories incineration and non-incineration. In this paper, life cycle assessment (LCA) was carried out to study the environmental impacts of these two kinds of remediation technologies in selected PCB contaminated sites, where Infrared High Temperature Incineration (IHTI) and Base Catalyzed Decomposition (BCD) were selected as representatives of incineration and non-incineration. A combined midpoint/damage approach was adopted by using SimaPro 7.2 and IMPACTA2002+ to assess the human toxicity, ecotoxicity, climate change impact, and resource consumption from the five subsystems of IHTI and BCD technologies, respectively. It was found that the major environmental impacts through the whole lifecycle arose from energy consumption in both IHTI and BCD processes. For IHTI, primary and secondary combustion subsystem contributes more than 50% of midpoint impacts concerning with carcinogens, respiratory inorganics, respiratory organics, terrestrial ecotoxity, terrestrial acidification/eutrophication and global warming. In BCD process, the rotary kiln reactor subsystem presents the highest contribution to almost all the midpoint impacts including global warming, non-renewable energy, non-carcinogens, terrestrial ecotoxity and respiratory inorganics. In the view of midpoint impacts, the characterization values for global warming from IHTI and
20. Effects of perinatal coexposure to methylmercury and polychlorinated biphenyls on neurobehavioral development in mice
Energy Technology Data Exchange (ETDEWEB)
Sugawara, Norio [Tohoku University School of Medicine, Environmental Health Sciences, Aoba-ku, Sendai (Japan); Hirosaki University Graduate School of Medicine, Department of Neuropsychiatry, Hirosaki (Japan); Ohba, Takashi; Nakai, Kunihiko; Nakamura, Tomoyuki; Suzuki, Keita; Kameo, Satomi; Shimada, Miyuki; Kurokawa, Naoyuki; Satoh, Chieko; Satoh, Hiroshi [Tohoku University School of Medicine, Environmental Health Sciences, Aoba-ku, Sendai (Japan); Kakita, Akiyoshi [Niigata University, Department of Pathological Neuroscience, Resource Branch for Brain Disease Research, Brain Research Institute, Niigata (Japan)
2008-06-15
Methylmercury (MeHg) and polychlorinated biphenyls (PCBs) are environmental pollutants that cause neurobehavioral deficits in humans. Because exposures to MeHg and PCBs occur through fish consumption, it is necessary to clarify the effects of the interaction of the two pollutants. Therefore, we investigated the effects of perinatal exposure to MeHg and PCBs on the neurobehavioral development in mice. Female mice (C57BL/6Cr) were divided into four groups according to the type of exposure: (1) vehicle control, (2) MeHg alone, (3) PCBs alone, and (4) MeHg + PCBs. The MeHg-exposed groups were fed with a diet containing 5 ppm MeHg (as Hg), from 4 weeks before mating, throughout pregnancy, and lactation. The PCB-exposed groups were given a commercial mixture of PCBs, Aroclor 1254, at 18 mg/kg body weight in corn oil by gavage every 3 days from day 5 after breeding and continued until postnatal day (PND) 20. Before weaning, an assessment of eye opening showed the interactive effects between MeHg and PCBs on PND 12: The coexposure group showed a similar response to the control group, whereas the MeHg- and PCB-exposed groups showed a high response than the former two groups. We also observed delay in development of grasp reflex by MeHg exposure on PNDs 12 and 14. When the offspring mice were 8 weeks old, the group exposed to PCBs alone showed increases in the frequencies of excrement defecation and urine traces in an open-field test. Analysis of the latency revealed the antagonistic interaction between the MeHg and PCBs: The latency increased by either MeHg or PCB exposure was decreased by coexposure. Treatment with MeHg decreased the distance walked by the mice, and MeHg interacted with PCBs. Moris' water maze test showed that the MeHg-treated mice took a long time to reach the submerged platform; however, this MeHg exposure showed no interaction with PCB exposure. The spontaneous locomotion activity of the mice was not affected by the chemical exposure at 9 weeks of
1. Omega-3 fatty acid oxidation products prevent vascular endothelial cell activation by coplanar polychlorinated biphenyls
International Nuclear Information System (INIS)
Majkova, Zuzana; Layne, Joseph; Sunkara, Manjula; Morris, Andrew J.; Toborek, Michal; Hennig, Bernhard
2011-01-01
Coplanar polychlorinated biphenyls (PCBs) may facilitate development of atherosclerosis by stimulating pro-inflammatory pathways in the vascular endothelium. Nutrition, including fish oil-derived long-chain omega-3 fatty acids, such as docosahexaenoic acid (DHA, 22:6ω-3), can reduce inflammation and thus the risk of atherosclerosis. We tested the hypothesis that cyclopentenone metabolites produced by oxidation of DHA can protect against PCB-induced endothelial cell dysfunction. Oxidized DHA (oxDHA) was prepared by incubation of the fatty acid with the free radical generator 2,2-azo-bis(2-amidinopropane) dihydrochloride (AAPH). Cellular pretreatment with oxDHA prevented production of superoxide induced by PCB77, and subsequent activation of nuclear factor-κB (NF-κB). A 4 /J 4 -neuroprostanes (NPs) were identified and quantitated using HPLC ESI tandem mass spectrometry. Levels of these NPs were markedly increased after DHA oxidation with AAPH. The protective actions of oxDHA were reversed by treatment with sodium borohydride (NaBH 4 ), which concurrently abrogated A 4 /J 4 -NP formation. Up-regulation of monocyte chemoattractant protein-1 (MCP-1) by PCB77 was markedly reduced by oxDHA, but not by un-oxidized DHA. These protective effects were proportional to the abundance of A 4 /J 4 NPs in the oxidized DHA sample. Treatment of cells with oxidized eicosapentaenoic acid (EPA, 20:5ω-3) also reduced MCP-1 expression, but less than oxDHA. Treatment with DHA-derived cyclopentenones also increased DNA binding of NF-E2-related factor-2 (Nrf2) and downstream expression of NAD(P)H:quinone oxidoreductase (NQO1), similarly to the Nrf-2 activator sulforaphane. Furthermore, sulforaphane prevented PCB77-induced MCP-1 expression, suggesting that activation of Nrf-2 mediates the observed protection against PCB77 toxicity. Our data implicate A 4 /J 4 -NPs as mediators of omega-3 fatty acid-mediated protection against the endothelial toxicity of coplanar PCBs.
2. A Reconnaissance of selected organic compounds in streams in tribal lands in Central Oklahoma, January-February 2009
Science.gov (United States)
Becker, Carol J.
2010-01-01
The U.S. Geological Survey worked in cooperation with the U.S. Environmental Protection Agency and the Kickapoo Tribe of Oklahoma on two separate reconnaissance projects carried out concurrently. Both projects entailed the use of passive samplers as a sampling methodology to investigate the detection of selected organic compounds at stream sites in jurisdictional areas of several tribes in central Oklahoma during January-February 2009. The focus of the project with the U.S. Environmental Protection Agency was the detection of pesticides and pesticide metabolites using Semipermeable Membrane Devices at five stream sites in jurisdictional areas of several tribes. The project with the Kickapoo Tribe of Oklahoma focused on the detection of pesticides, pesticide metabolites, polycyclic aromatic hydrocarbons, polychlorinated biphenyl compounds, and synthetic organic compounds using Semipermeable Membrane Devices and Polar Organic Chemical Integrative Samplers at two stream sites adjacent to the Kickapoo tribal lands. The seven stream sites were located in central Oklahoma on the Cimarron River, Little River, North Canadian River, Deep Fork, and Washita River. Extracts from SPMDs submerged at five stream sites, in cooperation with the U.S. Environmental Protection Agency, were analyzed for 46 pesticides and 6 pesticide metabolites. Dacthal, a pre-emergent herbicide, was detected at all five sites. Pendimethalin, also a pre-emergent, was detected at one site. The insecticides chlorpyrifos and dieldrin were detected at three sites and p,p'-DDE, a metabolite of the insecticide DDT, also was detected at three sites. SPMDs and POCIS were submerged at the upstream edge and downstream edge of the Kickapoo tribal boundaries. Both sites are downstream from the Oklahoma City metropolitan area and multiple municipal wastewater treatment plants. Extracts from the passive samplers were analyzed for 62 pesticides, 10 pesticide metabolites, 3 polychlorinated biphenyl compounds, 35
3. Concentrations, loads, and sources of polychlorinated biphenyls, Neponset River and Neponset River Estuary, eastern Massachusetts
Science.gov (United States)
Breault, Robert F.
2011-01-01
Polychlorinated biphenyls (PCBs) are known to contaminate the Neponset River, which flows through parts of Boston, Massachusetts, and empties into the Neponset River Estuary, an important fish-spawning area. The river is dammed and impassable to fish. The U.S. Geological Survey, in cooperation with the Massachusetts Department of Fish and Game, Division of Ecological Restoration, Riverways Program, collected, analyzed, and interpreted PCB data from bottom-sediment, water, and (or) fish-tissue samples in 2002, 2004-2006. Samples from the Neponset River and Neponset River Estuary were analyzed for 209 PCB congeners, PCB homologs, and Aroclors. In order to better assess the overall health quality of river-bottom sediments, sediment samples were also tested for concentrations of 31 elements. PCB concentrations measured in the top layers of bottom sediment ranged from 28 nanograms per gram (ng/g) just upstream of the Mother Brook confluence to 24,900 ng/g measured in Mother Brook. Concentrations of elements in bottom sediment were generally higher than background concentrations and higher than levels considered toxic to benthic organisms according to freshwater sediment-quality guidelines defined by the U.S. Environmental Protection Agency. Concentrations of dissolved PCBs in water samples collected from the Neponset River (May 13, 2005 to April 28, 2006) averaged about 9.2 nanograms per liter (ng/L) (annual average of monthly values); however, during the months of August (about 16.5 ng/L) and September (about 15.6 ng/L), dissolved PCB concentrations were greater than 14 ng/L, the U.S. Environmental Protection Agency's freshwater continuous chronic criterion for aquatic organisms. Concentrations of PCBs in white sucker (fillets and whole fish) were all greater than 2,000 ng/g wet wt, the U.S. Environmental Protection Agency's guideline for safe consumption of fish: PCB concentrations measured in fish-tissue samples collected from the Tileston and Hollingsworth and
4. Fluorine-18 labelled compounds
International Nuclear Information System (INIS)
Kleijn, J.P. de
1978-01-01
The work presented in this thesis deals with the problems involved in the adaption of reactor-produced fluorine-18 to the synthesis of 18 F-labelled organic fluorine compounds. Several 18 F-labelling reagents were prepared and successfully applied. The limitations to the synthetic possibilities of reactor-produced fluoride- 18 become manifest in the last part of the thesis. An application to the synthesis of labelled aliphatic fluoro amino acids has appeared to be unsuccessful as yet, although some other synthetic approaches can be indicated. Seven journal articles (for which see the availability note) are used to compose the four chapters and three appendices. The connecting text gives a survey of known 18 F-compounds and methods for preparing such compounds. (Auth.)
5. Chloric organic compound
International Nuclear Information System (INIS)
Moalem, F.
2000-01-01
Since many years ago, hazardous and toxic refuses which are results of human activities has been carelessly without any Biological and Engineering facts and knowledge discharged into our land and water. The effects of discharging those materials in environment are different. Some of refuse materials shows short and other has long-time adverse effects in our environment, Among hazardous organic chemical materials, chlorine, consider, to be the main element. Organic materials with chlorine is called chlorine hydrocarbon as a hazardous compound. This paper discuss the hazardous materials especially chloric organic compound and their misuse effects in environment and human being
6. Medicinal gold compounds
International Nuclear Information System (INIS)
Parish, R.V.; Cottrill, S.M.
1987-01-01
A major use of gold compounds in the pharmaceutical industry is for anti-arthritic agents. The disease itself is not understood and little is known about the way in which the drugs act, but detailed pictures of the distribution of gold in the body are available, and some of the relevant biochemistry is beginning to emerge. The purpose of this article is to give a survey of the types of compounds presently employed in medicine, of the distribution of gold in the body which results from their use, and of some relevant chemistry. Emphasis is placed on results obtained in the last few years
7. Compound semiconductor device physics
CERN Document Server
Tiwari, Sandip
2013-01-01
This book provides one of the most rigorous treatments of compound semiconductor device physics yet published. A complete understanding of modern devices requires a working knowledge of low-dimensional physics, the use of statistical methods, and the use of one-, two-, and three-dimensional analytical and numerical analysis techniques. With its systematic and detailed**discussion of these topics, this book is ideal for both the researcher and the student. Although the emphasis of this text is on compound semiconductor devices, many of the principles discussed will also be useful to those inter
8. Prediction of intermetallic compounds
International Nuclear Information System (INIS)
Burkhanov, Gennady S; Kiselyova, N N
2009-01-01
The problems of predicting not yet synthesized intermetallic compounds are discussed. It is noted that the use of classical physicochemical analysis in the study of multicomponent metallic systems is faced with the complexity of presenting multidimensional phase diagrams. One way of predicting new intermetallics with specified properties is the use of modern processing technology with application of teaching of image recognition by the computer. The algorithms used most often in these methods are briefly considered and the efficiency of their use for predicting new compounds is demonstrated.
9. Chemico-biological treatment of polluted soils by polychorinated biphenyls; Tratamiento integrado quimico-biologico de suelos contaminados por bifenilos policlorados
Energy Technology Data Exchange (ETDEWEB)
Manzano Quinones, M. A.
2001-07-01
In this work a study of biological and chemical treatment of polychlorinated biphenyls (PCBs) in soil has been done. The experiments have been carried out in pilot scale reactors and the results obtained showed 98% elimination and a high mineralization of PCBs employing a Integrated Chemical-Biological Treatment. (Author) 12 refs.
10. Background Contamination by Coplanar Polychlorinated Biphenyls (PCBS) in Trace Level High Resolution Gas Chromatography/High Resolution Mass Spectrometry (HRGC/HRMS) Analytical Procedures
Science.gov (United States)
The addition of the "dioxin-like" polychlorinated biphenyl (PCB) congeners to the assessment of risk associated with the 2,3,7,8-chlorine substituted dioxins and furans has dramatically increased the number of laboratories worldwide that are developing analytical procedures for t...
11. Laboratory Study of Polychlorinated Biphenyl (PCB) Contamination and Mitigation in Buildings -- Part 4. Evaluation of the Activated Metal Treatment System (AMTS) for On-site Destruction of PCBs
Science.gov (United States)
This is the fourth, also the last, report of the report series entitled “Laboratory Study of Polychlorinated Biphenyl (PCB) Contamination and Mitigation in Buildings.” This report evaluates the performance of an on-site PCB destruction method, known as the AMTS method, developed ...
12. DIFFUSIVE EXCHANGE OF GASEOUS POLYCYCLIC AROMATIC HYDROCARBONS AND POLYCHLORINATED BIPHENYLS ACROSS THE AIR-WATER INTERFACE OF THE CHESAPEAKE BAY. (R825245)
Science.gov (United States)
Dissolved and gas-phase concentrations of nine polycyclic aromatic hydrocarbons and 46 polychlorinated biphenyl congeners were measured at eight sites on the Chesapeake Bay at four different times of the year to estimate net diffusive air-water gas exchange rates. Gaseous PAHs ar...
13. Fluorescent deep-blue and hybrid white emitting devices based on a naphthalene-benzofuran compound
KAUST Repository
Yang, Xiaohui
2013-08-01
We report the synthesis, photophysics and electrochemical properties of naphthalene-benzofuran compound 1 and its application in organic light emitting devices. Fluorescent deep-blue emitting devices employing 1 as the emitting dopant embedded in 4-4′-bis(9-carbazolyl)-2,2′-biphenyl (CBP) host show the peak external quantum efficiency of 4.5% and Commission Internationale d\\'Énclairage (CIE) coordinates of (0.15, 0.07). Hybrid white devices using fluorescent blue emitting layer with 1 and a phosphorescent orange emitting layer based on an iridium-complex show the peak external quantum efficiency above 10% and CIE coordinates of (0.31, 0.37). © 2013 Published by Elsevier B.V.
14. Synthesis, crystal structure and luminescent properties of one 3D Cd(II) coordination polymer [Cd(H3BPTC)2(bpy)]n (H4BPTC = 1,1'-biphenyl-2,2',6,6'-tetracarboxylic acid, bpy = 4,4'-bipyridine).
Science.gov (United States)
Mei, Chong-Zhen; Shan, Wen-Wen; Liu, Bing-Tao
2011-10-15
A new 3D metal-organic coordination polymer [Cd(H(3)BPTC)(2)(bpy)](n) (1) (H(4)BPTC = 1,1'-biphenyl-2,2',6,6'-tetracarboxylic acid, bpy =4,4'-bipyridine) has been synthesized and characterized by single X-ray diffraction and IR spectroscopy. The one-dimensional metal-organic chains of the title complex, namely [Cd(H(3)BPTC)(2)](n), are held together through hydrogen bonding and bridging "second" ligand 4,4'-bpy to give a three-dimensional metal-organic network. The thermal stability of complex 1 was studied by thermal gravimetric (TG) and differential thermal analysis (DTA). Compound 1 exhibits photoluminescence with an emission maximum at ca. 380 nm upon excitation at ca. 251 nm. Copyright © 2011 Elsevier B.V. All rights reserved.
15. Dioxins and polychlorinated biphenyls concentrations in Larus dominicanus. Case study: Marambaia island, Sepetiba bay, Rio de Janeiro State, Brazil - doi: 10.4025/actascibiolsci.v35i3.18344
Directory of Open Access Journals (Sweden)
Aldo Pacheco Ferreira
2013-08-01
Full Text Available Seabirds play a significant role as bioindicators: they are conspicuous, relatively easy to observe, well-established studied group of organisms, and in the focus of public interest due to pollution in aquatic ecosystem. Systematically, a significant number of man-made chemicals have been introduced in the marine environment and represent the major problem arising in the development worldwide. Many of these chemical contaminants are persistent, known to bioaccumulate and biomagnify through the aquatic food web, affecting species associated with aquatic systems. Dioxins [polychlorinated dibenzo-p-dioxins (PCDD, dibenzofurans (PCDF] and polychlorinated biphenyls (PCB concentrations were measured in Kelp gull Larus dominicanus collected from 2006 to 2011 on Marambaia Island, Sepetiba Bay, Rio de Janeiro State, Brazil. Detectable liver concentrations of PCDD Fs-1 and PCBs were found in all samples analyzed. These represent some of the first measurements of PCDD Fs-1 and PCBs in seabirds from this area. Although levels of these contaminants in the tested species currently appear to fall below critical values, a continuous and systematic monitoring on these compounds becomes essential and desirable to not express toxic values in the future.
16. Characterization of polychlorinated dibenzo-p-dioxins and dibenzofurans, dioxin-like polychlorinated biphenyls, and polychlorinated naphthalenes in the environment surrounding secondary copper and aluminum metallurgical facilities in China.
Science.gov (United States)
Hu, Jicheng; Zheng, Minghui; Liu, Wenbin; Nie, Zhiqiang; Li, Changliang; Liu, Guorui; Xiao, Ke
2014-10-01
Unintentionally produced persistent organic pollutants (UP-POPs) were determined in ambient air from around five secondary non-ferrous metal processing plants in China, to investigate the potential impacts of the emissions of these plants on their surrounding environments. The target compounds were polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), and polychlorinated naphthalenes (PCNs). The PCDD/F, dl-PCB, and PCN concentrations in the ambient air downwind of the plants were 4.70-178, 8.23-7520 and 152-4190 pg/m(3), respectively, and the concentrations upwind of the plants were lower. Clear correlations were found between ambient air and stack gas concentrations of the PCDD/Fs, dl-PCBs, and PCNs among the five plants, respectively. Furthermore, the UP-POPs homolog and congener patterns in the ambient air were similar to the patterns in the stack gas samples. These results indicate that UP-POPs emissions from the plants investigated have obvious impacts on the environments surrounding the plants. Copyright © 2014 Elsevier Ltd. All rights reserved.
17. Temporal trend of polychlorinated dibenzo-p-dioxin/polychlorinated dibenzofuran and dioxin like-polychlorinated biphenyl concentrations in food from Taiwan markets during 2004–2012
Directory of Open Access Journals (Sweden)
Ching-Chang Lee
2016-07-01
Full Text Available The levels of polychlorinated dibenzo-p-dioxin (PCDD and polychlorinated dibenzofuran (PCDF or polychlorinated biphenyl (PCB in foodstuffs have decreased over the past decade in many countries. However, the trend for the levels of these compounds in foodstuffs in Taiwan remains unknown. In this study, we compared the distribution of PCDD/F and PCB in nine foodstuff categories acquired from Taiwan markets from 2004 to 2012. The levels expressed as World Health Organization toxic equivalents (WHO-TEQs in the different foodstuffs tested were as follows: fish, average 0.463 pg WHO98-TEQ/g sample > seafood, 0.163 pg WHO98-TEQ/g > eggs, 0.150 pg WHO98-TEQ/g > oils, 0.126 pg WHO98-TEQ/g > meats, 0.095 pg WHO98-TEQ/g > dairy products, 0.054 pg WHO98-TEQ/g > cereals, 0.017 pg WHO98-TEQ/g > vegetables, 0.013 pg WHO98-TEQ/g > fruits, 0.009 pg WHO98-TEQ/g. Levels were particularly high in crab (average: 0.6 pg WHO98-TEQ/g sample (1.243 pg WHO98-TEQ/g sample and large marine fish (0.6. In Taiwan, a decreasing trend of PCDD/Fs or dioxin-like PCBs (dl-PCBs was observed in meat, dairy, eggs, and vegetables, whereas an elevated trend was observed in cereals or the levels were nearly equal in fruits and oils at alternative time shift. Dl-PCBs contributed to 60–65% toxicity equivalence levels in fish and seafood, but only to 13–40% in meat and cereal samples. The decreasing trend was consistent with the results in other countries; however, the trends in cereals, fruits, and oils were in contrast to previous results reported in other countries. Cereals and fruits are important crops in southern Taiwan, and the local pollution generated by industries or incinerators may seriously affect the distribution of PCDD/Fs and dl-PCBs. To ensure food safety, a risk assessment for residents living in different areas should be adopted for all food categories simultaneously in the future.
18. Cytochrome P4501A induction in avian hepatocyte cultures exposed to polychlorinated biphenyls: Comparisons with AHR1-mediated reporter gene activity and in ovo toxicity
Energy Technology Data Exchange (ETDEWEB)
2013-01-01
Avian-specific toxic equivalency factors (TEFs) were developed by the World Health Organization to simplify environmental risk assessments of dioxin-like compounds (DLCs), but TEFs do not account for differences in the toxic and biochemical potencies of DLCs among species of birds. Such variability may be due to differences in species sensitivity to individual DLCs. The sensitivity of avian species to DLCs was recently associated with the identity of amino acids 324 and 380 in the aryl hydrocarbon receptor 1 (AHR1) ligand binding domain. A luciferase reporter gene (LRG) assay, measuring AHR1-mediated induction of a cytochrome P450 1A5 (CYP1A5) reporter gene, in combination with a species' AHR1 ligand binding domain sequence, were also shown to predict avian species sensitivity to polychlorinated biphenyls (PCBs) and PCB relative potency in a given species. The goals of the present study were to (1) characterize the concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and PCBs 126, 77, 105 and 118 on induction of ethoxyresorufin O-deethylase (EROD) activity and CYP1A4/5 mRNA in chicken, ring-necked pheasant and Japanese quail embryo hepatocytes and (2) compare these in vitro results to those previously generated by the LRG assay and in ovo toxicity studies. EROD activity and CYP1A4/5 mRNA expression data support and complement the findings of the LRG assay. CYP1A enzyme activity and mRNA expression were significantly correlated both with luciferase activity and in ovo toxicity induced by PCBs. Relative potency values were generally similar between the LRG and EROD assays and indicate that the relative potency of some PCBs may differ among species. -- Highlights: ► The chicken isn't the most sensitive species to CYP1A induction by PCB 105 and 118. ► The relative potency of PCBs differs between avian species. ► EROD activity was correlated with luciferase activity from the LRG assay. ► EROD activity was a better predictor of
19. Cytochrome P4501A induction in avian hepatocyte cultures exposed to polychlorinated biphenyls: Comparisons with AHR1-mediated reporter gene activity and in ovo toxicity
International Nuclear Information System (INIS)
Manning, Gillian E.; Mundy, Lukas J.; Crump, Doug; Jones, Stephanie P.; Chiu, Suzanne; Klein, Jeff; Konstantinov, Alex; Potter, Dave; Kennedy, Sean W.
2013-01-01
Avian-specific toxic equivalency factors (TEFs) were developed by the World Health Organization to simplify environmental risk assessments of dioxin-like compounds (DLCs), but TEFs do not account for differences in the toxic and biochemical potencies of DLCs among species of birds. Such variability may be due to differences in species sensitivity to individual DLCs. The sensitivity of avian species to DLCs was recently associated with the identity of amino acids 324 and 380 in the aryl hydrocarbon receptor 1 (AHR1) ligand binding domain. A luciferase reporter gene (LRG) assay, measuring AHR1-mediated induction of a cytochrome P450 1A5 (CYP1A5) reporter gene, in combination with a species' AHR1 ligand binding domain sequence, were also shown to predict avian species sensitivity to polychlorinated biphenyls (PCBs) and PCB relative potency in a given species. The goals of the present study were to (1) characterize the concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and PCBs 126, 77, 105 and 118 on induction of ethoxyresorufin O-deethylase (EROD) activity and CYP1A4/5 mRNA in chicken, ring-necked pheasant and Japanese quail embryo hepatocytes and (2) compare these in vitro results to those previously generated by the LRG assay and in ovo toxicity studies. EROD activity and CYP1A4/5 mRNA expression data support and complement the findings of the LRG assay. CYP1A enzyme activity and mRNA expression were significantly correlated both with luciferase activity and in ovo toxicity induced by PCBs. Relative potency values were generally similar between the LRG and EROD assays and indicate that the relative potency of some PCBs may differ among species. -- Highlights: ► The chicken isn't the most sensitive species to CYP1A induction by PCB 105 and 118. ► The relative potency of PCBs differs between avian species. ► EROD activity was correlated with luciferase activity from the LRG assay. ► EROD activity was a better predictor of toxicity than CYP
20. Compound floating pivot micromechanisms
Science.gov (United States)
Garcia, Ernest J.
2001-04-24
A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use compound floating pivot structures to attain far greater tilt angles than are practical using other micromechanical techniques. The new mechanisms are also capable of bi-directional tilt about multiple axes.
1. The Onium Compounds
Science.gov (United States)
Tsarevsky, Nicolay V.; Slaveykova, Vera; Manev, Stefan; Lazarov, Dobri
1997-06-01
The onium salts are of a big interest for theoretical and structural chemistry, and for organic synthesis. Some representatives of the group (e.g. ammonium salts) were known from the oldest times. Many onium salts are met the nature: ammonium salts (either as inorganic salts, and organic derivatives, e.g. aminoacids, salts of biogenic amines and alkaloids, etc.); oxonium salts (plant pigments as anthocyans are organic oxonium compounds), etc. In 1894 C. Hartmann and V. Meyer prepared the first iodonium salts - 4-iododiphenyliodonium hydrogensulfate and diphenyliodonium salts, and suggested the ending -onium for all compounds with properties similar to those of ammonium salts. Nowadays onium compounds of almost all nonmetals are synthesised and studied. A great variety of physical methods: diffraction (e.g. XRD) and spectral methods (IR-, NMR-, and UV-spectra), as well as the chemical properties and methods of preparation of onium salts have been used in determination of the structure of these compounds. The application of different onium salts is immense. Ammonium, phosphonium and sulfonium salts are used as phase-transfer catalysts; diazonium salts - for the preparation of dyes, metalochromic and pH-indicators. All the onium salts and especially diazonium and iodonium salts are very useful reagents in organic synthesis.
2. Forecasting of superconducting compounds
International Nuclear Information System (INIS)
Savitskii, E.M.; Gribulya, V.G.; Kiseleva, N.N.
1981-01-01
In forecasting new superconducting intermetallic compounds of the A15 and Mo 3 Se types most promising from the viewpoint of high critical temperature Tsub(c), high critical magnetic fields Hsub(c), and high critical currents and in estimating their transition temperature it is proposed to apply cybernetic methods of computer learning
3. NATURAL POLYACETYLENE COMPOUNDS
Directory of Open Access Journals (Sweden)
A. M. Nasukhova
2014-01-01
Full Text Available In article the review of the initial stage of researches of natural polyacetylene compounds is resulted. The high reactionary ability leading to fast oxidation and degradation of these compounds, especially at influence of Uf-light, oxygen of air, pH and other factors, has caused the serious difficulties connected with an establishment of structure and studying of their physical and chemical properties. Therefore the greatest quantity of works of this stage is connected with studying of essential oils of plants from families Apiaceae, Araliaceae, Asteraceae, Campanulaceae, Olacaceae, Pittosporaceae and Santalaceae where have been found out, basically, diacetylene compounds. About development of physical and chemical methods of the analysis of possibility of similar researches have considerably extended. More than 2000 polyacetylenes are known today, from them more than 1100 are found out in plants fam. Asteraceae. Revolution in the field of molecular biology has allowed to study processes of biosynthesis of these compounds intensively.
4. Aminopropyl thiophene compounds
International Nuclear Information System (INIS)
Goodman, M.M.; Knapp, F.F.
1990-01-01
This patent describes radiopharmaceuticals useful in brain imaging comprising radiohalogenated thienylethylamine derivatives. The compounds are 5-halo-thiophene-2-isopropyl amines able to cross the blood-brain barrier and be retained for a sufficient length of time to allow the evaluation of regional blood flow by radioimaging of the brain
5. Aminopropyl thiophene compounds
Science.gov (United States)
Goodman, Mark M.; Knapp, Jr., Furn F.
1990-01-01
Radiopharmaceuticals useful in brain imaging comprising radiohalogenated thienylethylamine derivatives. The compounds are 5-halo-thiophene-2-isopropyl amines able to cross the blood-brain barrier and be retained for a sufficient length of time to allow the evaluation of regional blood flow by radioimaging of the brain.
6. Hyperon compound nucleus
International Nuclear Information System (INIS)
Yamazaki, Toshimitsu.
1987-11-01
The formation of various hypernuclei from K - absorption at rest is discussed from the viewpoints of compound decay of highly excited hypernuclei in contrast to the direct reaction mechanism. Recent (stopped K - , π) experiments at KEK as well as old data of emulsion and bubble chamber experiments are discussed. Some future direction of hypernuclear spectroscopy is suggested. (author)
7. Toxicology of perfluorinated compounds
Energy Technology Data Exchange (ETDEWEB)
Stahl, Thorsten [Hessian State Laboratory, Wiesbaden (Germany); Mattern, Daniela; Brunn, Hubertus [Hessian State Laboratory, Giessen (Germany)
2011-12-15
Perfluorinated compounds [PFCs] have found a wide use in industrial products and processes and in a vast array of consumer products. PFCs are molecules made up of carbon chains to which fluorine atoms are bound. Due to the strength of the carbon/fluorine bond, the molecules are chemically very stable and are highly resistant to biological degradation; therefore, they belong to a class of compounds that tend to persist in the environment. These compounds can bioaccumulate and also undergo biomagnification. Within the class of PFC chemicals, perfluorooctanoic acid and perfluorosulphonic acid are generally considered reference substances. Meanwhile, PFCs can be detected almost ubiquitously, e.g., in water, plants, different kinds of foodstuffs, in animals such as fish, birds, in mammals, as well as in human breast milk and blood. PFCs are proposed as a new class of 'persistent organic pollutants'. Numerous publications allude to the negative effects of PFCs on human health. The following review describes both external and internal exposures to PFCs, the toxicokinetics (uptake, distribution, metabolism, excretion), and the toxicodynamics (acute toxicity, subacute and subchronic toxicities, chronic toxicity including carcinogenesis, genotoxicity and epigenetic effects, reproductive and developmental toxicities, neurotoxicity, effects on the endocrine system, immunotoxicity and potential modes of action, combinational effects, and epidemiological studies on perfluorinated compounds). (orig.)
8. Chemical compounds in teak
Directory of Open Access Journals (Sweden)
Fernanda Viana da Silva Leonardo
2015-09-01
Full Text Available Quinone compounds are largely generated at extractive fraction of the woods in a complex and variable biological system. The literature has indications for many segments from food industry to pharmaceutical industry. Within the field of industrial use of wood, they are less desirable since they are treated only as incidental substances in production strings of pulp, paper, charcoal, and sawmill. In spite of its small amount, compared to other chemical compounds called essential, these substances have received special attention from researchers revealing a diverse range of offerings to market products textiles, pharmaceuticals, colorants, and other polymers, for which are being tested and employed. Quinones are found in fungi, lichens, and mostly in higher plants. Tectona grandis, usually called teak, is able to biosynthesize anthraquinones, which is a quinone compound, byproduct of secondary metabolism. This species provides wood that is much prized in the furniture sector and can also be exploited for metabolites to supply the market in quinone compounds and commercial development of new technologies, adding value to the plantations of this species within our country.
9. Hydroxylated polychlorinated biphenyls decrease circulating steroids in female polar bears (Ursus maritimus)
DEFF Research Database (Denmark)
Gustavson, Lisa; Ciesielski, Tomasz M; Bytingsvik, Jenny
2015-01-01
), androstenedione (AN), testosterone (TS), dihydrotestosterone (DHT), estrone (E1), 17α-estradiol (αE2), 17β-estradiol (βE2), pregnenolone (PRE) and progesterone (PRO) were determined. The aim of the study was to investigate associations among circulating levels of specific POP compounds and POP...
10. Hydroxylated polychlorinated biphenyls decrease circulating steroids in female polar bears (Ursus maritimus)
DEFF Research Database (Denmark)
Gustavson, Lisa; Ciesielski, Tomasz M.; Bytingsvik, Jenny
2015-01-01
), androstenedione (AN), testosterone (TS), dihydrotestosterone (DHT), estrone (E1), 17α-estradiol (αE2), 17β-estradiol (βE2), pregnenolone (PRE) and progesterone (PRO) were determined. The aim of the study was to investigate associations among circulating levels of specific POP compounds and POP...
11. Selenium-75-labelled foliate compounds
International Nuclear Information System (INIS)
1974-01-01
A saturation method to analyze a foliate is presented; it uses competitive reaction of the compound to be measured and of a radioactive-labelled version of this compound with a reagent specific to this compound present in insufficient quantity to combine with the whole of the compound and its labelled version, separation of the bound compound from its non-bound homologue and measurement of the radioactivity concentration in the bound compound, the non-bound compound or both. The radioactive isotope used in the labelled foliate is selenium 75 [fr
12. Tracking Polychlorinated Biphenyls (PCB) after an incident along a river system - Case study Elbe River
Science.gov (United States)
Kleisinger, Carmen; Dietrich, Stephan; Kehl, Nora; Claus, Evelyn; Schubert, Birgit
2017-04-01
In spring 2015, extremely high concentrations of Polychlorinated Biphenyls (PCB) well above the long-term average were detected in suspended particulate matter (SPM) within the River Elbe. They were released due to abrasive blasting of the old coating from a bridge in the upper part of the River, approximately 50 km upstream of the first measurement site. PCBs are persistent organic pollutants, preferentially bound to fine-grained fractions of the SPM. Results from monitoring of contaminants in SPM along the Elbe indicate the further dispersal of the PCB-contaminated sediments. These measurements include yearly investigations on PCB concentrations in sediments in the inner reaches of the Elbe, an additional longitudinal survey in 2015 and monthly monitoring of PCBs in SPM at stations along the river including the Elbe estuary (Germany). The Elbe estuary is of major economic importance since Hamburg harbour, one of the largest harbours in Europe, is located there. Maintaining the harbour includes dredging and, i.a., relocating large amounts of the dredged material within the water body. High PCB concentrations in sediments could lead to restrictions on the relocation of these sediments. This study aims at tracking the fate of PCB contaminated material released from the point source of the incident site along the whole river stretch and at estimating its impact on the quality of sediments and consequently on dredging activities in the estuary. The ratio of high (PCB 138, 152 and 180) versus low (PCB 28, 52, 101) chlorinated PCB congeners proved to be a suitable tracer to distinguish the PCB load released by the incident from the long-term background signals. As Delor 106/Clophen A60, which contains approx. 90% hexa- to decachloric congeners, was an additive in the coating of the bridge, the pattern of PCBs released by the incident is dominated by the highly chlorinated PCB-congeners PCB 138, 153 and 180. At the tidal weir Geesthacht, the entrance to the estuary, an
13. POLYCHLORINATED BIPHENYL COMPLIANCE ISSUES IN THE 21ST CENTURY: POORLY RECOGNIZED AND POTENTIALLY DEVASTATING-8162
International Nuclear Information System (INIS)
Lowry, N
2007-01-01
Thirty-one years have passed since the United States Congress passed the Toxic Substances Control Act (TSCA) [1]. The 1976 law essentially eliminated future production of polychlorinated biphenyls (PCBs) within the United States and greatly limited the use of previously manufactured PCBs and PCB products. The ultimate objective of the law was the complete elimination of these chemicals due to concerns about their potentially toxic effects on health and the environment. PCBs were manufactured in the United States between 1929 and 1977. They were highly valued for their fire and heat-resistance properties and for their chemical stability. As a result, PCBs were used in a variety of thermally and/or chemically stressful applications. They did not conduct electricity and therefore were particularly well-suited for use as insulating fluids in high-voltage electric equipment. PCBs were also used in various other applications, such as in hydraulic and heat transfer fluids. Strict controls on the use and disposal of PCBs were imposed by the TSCA implementing regulations at 40 CFR 761 [2]. As a result, most heavy users of PCB products worked hard to curtail their PCB use. Many organizations that once used substantial amounts of PCBs, subsequently declared themselves ''PCB free''. Unfortunately, in many cases, these ''PCB-free'' declarations were premature, as PCBs were used in many more applications than insulating fluids. From the 1990s and to the present day, PCBs increasingly have been discovered in non-liquid forms. These materials were used or installed in facilities constructed before the 1979 ''PCB ban''. Examples include applied paints and coatings, caulking, pre-formed joint filler, and plastic or rubber wire and cable insulation. Proper identification of these materials is necessary for appropriate and compliant waste management during decommissioning and deactivation (D and D) activities. PCBs can pose other significant waste management issues for D and D
14. Congener specific distribution and health risk assessment of polychlorinated biphenyls in urban soils
Directory of Open Access Journals (Sweden)
Bhupander Kumar
2012-10-01
Full Text Available Polychlorinated biphenyls (PCBs were primarily used in transformers and capacitors, lubricants, flame retardants, plasticizers, paint, carbonless papers, etc. These are capable of long-range atmospheric transport and have been designated as persistent organic pollutants by the Stockholm Convention. Due to their characteristic properties, PCBs are found worldwide in all environmental matrices (including human and biota. Soils are usually considered to be the source as well as sink for environmental pollutants, with cumulative effects of long-range atmospheric transport and local sources. Around the world, comparatively higher concentrations of PCBs have been reported in urban soils than suburban or rural soils. Higher amount of PCBs in urban soils may cause toxicological health risks to urban residents through ingestion, inhalation and skin contact. This paper presents the PCB distribution in soils from Delhi, India, and exposure risk estimates for human health through soil ingestion. The concentration of ΣPCBs ranged between 1.08-100.67 ng g–1 (mean 21.16 ng g–1±5.24 ng g–1, which was much lower than the Canadian soil quality guideline value of 1.3 mg/kg or 1300 ng g–1. Human health risk estimates through the soil ingestion pathway were made in terms of lifetime average daily dose (LADD, incremental lifetime cancer risks and non-carcinogenic hazard quotient (HQ. The LADD for Delhi adults and children was 3.02x10–8 mg kg–1 d–1 and 1.57x10–7 mg kg–1 d–1, respectively, which corresponds to toxic equivalent quotients (TEQ intake of 0.105 pg TEQ kg–1 d–1 (0.735 pg TEQ kg–1 week–1 and 0.543 pg TEQ kg–1 d–1 (3.801 pg TEQ kg–1 week–1, respectively. The estimated LADD for Delhi residents was lower than the acceptable
15. Cucurbita spp. and Cucumis sativus enhance the dissipation of polychlorinated biphenyl congeners by stimulating soil microbial community development.
Science.gov (United States)
Qin, Hua; Brookes, Philip C; Xu, Jianming
2014-01-01
A number of Cucurbita species have the potential to extract polychlorinated biphenyls (PCBs) from soil, but their impact on the soil microbial communities responsible for PCB degradation remains unclear. A greenhouse experiment was conducted to investigate the effect of three Cucurbita and one Cucumis species on PCB dissipation and soil microbial community structure. Compared to the unplanted control, enhanced losses of PCBs (19.5%-42.7%) were observed in all planted soils. Cucurbita pepo and Cucurbita moschata treatments were more efficient in PCB dissipation, and have similar patterns of soil phospholipid fatty acids (PLFAs) and PCB congener profiles. Cucurbita treatments tend to have higher soil microbial biomass than Cucumis. Gram-negative (G(-)) bacteria were significantly correlated with PCB degradation rates (R(2) = 0.719, p Cucurbita related soil microorganisms could play an important role in remediation of PCB contaminated soils. Copyright © 2013 Elsevier Ltd. All rights reserved.
16. Through-plane uniformity of optical anisotropy in spin-coated biphenyl dianhydride-p-phenylenediamine films
International Nuclear Information System (INIS)
Diao Jie; Hess, Dennis W.
2005-01-01
The uniformity of the average refractive index and birefringence of poly-(biphenyl dianhydride-p-phenylenediamine) (BPDA-PDA) films has been investigated experimentally as a function of film thickness. Spin-cast and cured BPDA-PDA films were thinned sequentially by reactive ion etching and the dependence of average refractive index and birefringence on the post-thinned film thickness was determined using a prism wave-guide coupler. Negligible changes in the average refractive index and the birefringence were observed as a result of the thinning process. These results confirm previous assumptions that assert uniform optical anisotropy in the through-plane direction for spin-cast BPDA-PDA films
17. Dynamic Covalent Chemistry within Biphenyl Scaffolds: Reversible Covalent Bonding, Control of Selectivity, and Chirality Sensing with a Single System.
Science.gov (United States)
Ni, Cailing; Zha, Daijun; Ye, Hebo; Hai, Yu; Zhou, Yuntao; Anslyn, Eric V; You, Lei
2018-01-26
Axial chirality is a prevalent and important phenomenon in chemistry. Herein we report a combination of dynamic covalent chemistry and axial chirality for the development of a versatile platform for the binding and chirality sensing of multiple classes of mononucleophiles. An equilibrium between an open aldehyde and its cyclic hemiaminal within biphenyl derivatives enabled the dynamic incorporation of a broad range of alcohols, thiols, primary amines, and secondary amines with high efficiency. Selectivity toward different classes of nucleophiles was also achieved by regulating the distinct reactivity of the system with external stimuli. Through induced helicity as a result of central-to-axial chirality transfer, the handedness and ee values of chiral monoalcohol and monoamine analytes were reported by circular dichroism. The strategies introduced herein should find application in many contexts, including assembly, sensing, and labeling. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
18. Polychlorinated biphenyls (PCBs) in indoor air originating from sealants in contaminated and uncontaminated apartments within the same housing estate
DEFF Research Database (Denmark)
Frederiksen, Marie; Meyer, Harald William; Ebbehøj, Niels Erik
2012-01-01
. The PCB(tot) levels in the air of the contaminated section were 168-3843 ng m(-3) (mean: 1030 ng m(-3)), while the mean levels in the reference apartments were 6.03 ng m(-3). The sum of the 24 measured PCB congeners in sealants from the contaminated section was 187-221680 mg kg(-1). Principal component......Twenty-four congeners of polychlorinated biphenyls (PCBs) were measured in 83 air samples and 20 elastic sealants samples of apartments with PCB-containing sealants. In addition, PCBs were measured in 21 air samples from reference apartments located in an uncontaminated section of the same estate...... analysis revealed four groups among the sealant samples with different congener compositions, only two of which were clearly similar to known PCB mixtures, while two were not. Significant correlations and intercorrelations were observed between the lower chlorinated congeners in air and sealant, e...
19. Accreditation of a screening method for non-dioxin-like polychlorinated biphenyl detection in fishery products according to European legislation.
Science.gov (United States)
Serpe, F P; Russo, R; Ambrosio, L; Esposito, M; Severino, L
2013-06-01
European Commission Regulation 882/2004/EC requires that official control laboratories for foodstuffs in the member states are certified according to UNI EN ISO/IEC 17025:2005 (general requirement for the competence of calibration and testing laboratories). This mandatory requirement has resulted in a continuous adaptation and development of analytical procedures. The aim of this study was to develop a method for semiquantitative screening of polychlorinated biphenyls in fish for human consumption. According to the Commission Decision 657/2002/CE, the detection capability, the precision, the selectivity-specificity, and applicability-ruggedness-stability were determined to validate the method. Moreover, trueness was verified. This procedure resulted in rapid execution, which allowed immediate and effective intervention by the local health authorities to protect the health of consumers. Finally, the procedure has been recognized by the Italian accrediting body, ACCREDIA.
20. Simultaneous extraction and clean-up of polychlorinated biphenyls and their metabolites from small tissue samples using pressurized liquid extraction
Science.gov (United States)
Kania-Korwel, Izabela; Zhao, Hongxia; Norstrom, Karin; Li, Xueshu; Hornbuckle, Keri C.; Lehmler, Hans-Joachim
2008-01-01
A pressurized liquid extraction-based method for the simultaneous extraction and in situ clean-up of polychlorinated biphenyls (PCBs), hydroxylated (OH)-PCBs and methylsulfonyl (MeSO2)-PCBs from small (< 0.5 gram) tissue samples was developed and validated. Extraction of a laboratory reference material with hexane:dichloromethane:methanol (48:43:9, v/v) and Florisil as fat retainer allowed an efficient recovery of PCBs (78–112%; RSD: 13–37%), OH-PCBs (46±2%; RSD: 4%) and MeSO2-PCBs (89±21%; RSD: 24%). Comparable results were obtained with an established analysis method for PCBs, OH-PCBs and MeSO2-PCBs. PMID:19019378
1. Polychlorinated biphenyls (PCBs) and dichlorodiphenyl dichloroethene (DDE) in human milk: effects on growth, morbidity, and duration of lactation
Energy Technology Data Exchange (ETDEWEB)
Rogan, W.J.; Gladen, B.C.; McKinney, J.D.; Carreras, N.; Hardy, P.; Thullen, J.; Tingelstad, J.; Tully, M.
1987-10-01
The authors followed 858 children from birth to one year of age to determine whether the presence of polychlorinated biphenyls (PCBs) and dichlorodiphenyl dichloroethene (DDE) in breast milk affected their growth or health. Neither chemical showed an adverse effect on weight or frequency of physician visits for various illnesses, although differences were seen between breast-fed and bottle-fed children, with bottle-fed children being heavier and having more frequent gastroenteritis and otitis media. Children of mothers with higher levels of DDE were breast-fed for markedly shorter times, but adjustments for possible confounders and biases did not change the findings. In absence of any apparent effect on the health of the children, they speculate that DDE may be interfering with the mother's ability to lactate, possibly because of its estrogenic properties.
2. Organochlorine pesticides and polychlorinated biphenyls in various tissues of waterbirds in Nalabana bird sanctuary, Chilika Lake, Orissa, India.
Science.gov (United States)
Dhananjayan, V
2012-07-01
In order to understand whether organochlorine pesticides and polychlorinated biphenyls (PCBs) are responsible for the mortality of waterbirds in Nalaban bird sanctuary in Chilika Lake, the current investigation was carried out in tissues of 11 individuals comprising 7 species of birds. One or more residues were detected in all the tissues of birds analysed. Concentration of ∑HCH, ∑DDT, and ∑PCBs were ranged from below detectable level (BDL)-811 ng/g, BDL-1,987 ng/g and BDL-1,027 ng/g respectively. PCBs levels were less than the food and drug administration's (FDA) action limits. Although varying levels of residues were detected among tissues, they do not appear to be responsible for the mass mortality of waterfowl. However, the need for additional research is heightened when considering that some of the birds are classified as a globally protected species by the international bodies.
3. Increase deposition of organic matter, polychlorinated biphenyls, and cadmium by zebra mussels (Dreissena polymorpha) in western Lake Erie
Energy Technology Data Exchange (ETDEWEB)
Dobson, E. P; Mackie, G. L. [Guelph Univ., Dept. of Zoology, ON (Canada)
1998-05-01
Biodeposition of polychlorinated biphenyls (PCBs)and cadmium by zebra mussels in the western basin of Lake Erie was investigated using sediment traps, and compared to natural rates of sedimentation. On a per unit area of organic matter, deposition rates by zebra mussels up to eight to ten times higher than natural rates of sedimentation were found. These results suggest that zebra mussels are altering contaminant movement in western Lake Erie. At the same time, it was also suggested that the net effect of biodeposition may not be as great as shown in this study since only the effects of zebra mussels on the flux of the contaminants was examined and the re-suspension factor was not considered. It was recommended that to better understand the overall effects of zebra mussels on contaminant dynamics in aquatic environments, future studies should incorporate the re-suspension factors. 27 refs., 8 tabs., 3 figs.
4. Non-Steroidal Biphenyl Gelators: Correlation of Xerogel Structure with Solid-State Structure and Circular Dichroism Spectroscopy
Directory of Open Access Journals (Sweden)
H. Cristina Geiger
2018-04-01
Full Text Available Because the factors favoring the formation of well-formed single crystals are dissimilar to those conducive to gel formation, few examples of single-crystal structural characterizations of organogelators are found in the literature. A series of biphenyl methyl and ethyl diester derivatives of varying chain length were synthesized and their gelation abilities explored. X-ray diffraction of single crystals of one of the gelators reveals a columnar extended structure. Based on XRD results for xerogels obtained from the reported organogelators, the members of the series are isostructural and so also adopt a columnar superstructure. Scanning electron microscopy (SEM was used for the investigation of the morphology of the xerogels, which display either platelet-like morphologies or more typical entangled twisted ribbon-like aggregates. The gels exhibit chirality, which depends on the sol-gel transition history, as observed by induced circular dichroism (ICD spectroscopy.
5. Equilibrium sampling of polychlorinated biphenyls in River Elbe sediments – Linking bioaccumulation in fish to sediment contamination
DEFF Research Database (Denmark)
Schäfer, Sabine; Antoni, Catherine; Möhlenkamp, Christel
2015-01-01
Equilibrium sampling can be applied to measure freely dissolved concentrations (cfree) of hydrophobic organic chemicals (HOCs) that are considered effective concentrations for diffusive uptake and partitioning. It can also yield concentrations in lipids at thermodynamic equilibrium...... with the sediment (Clip⇔sed) by multiplying concentrations in the equilibrium sampling polymer with lipid to polymer partition coefficients. We have applied silicone coated glass jars for equilibrium sampling of seven ‘indicator’ polychlorinated biphenyls (PCBs) in sediment samples from ten locations along...... bioaccumulation and the thermodynamic potential of sediment-associated HOCs for partitioning into lipids. This novel approach gives clearer and more consistent results compared to conventional approaches that are based on total concentrations in sediment and biota-sediment accumulation factors. We propose...
6. Low dose organochlorine pesticides and polychlorinated biphenyls predict obesity, dyslipidemia, and insulin resistance among people free of diabetes.
Directory of Open Access Journals (Sweden)
Duk-Hee Lee
2011-01-01
Full Text Available There is emerging evidence that background exposure to persistent organic pollutants (POPs are important in the development of conditions predisposing to diabetes as well as of type 2 diabetes itself. We recently reported that low dose POPs predicted incident type 2 diabetes in a nested case-control study. The current study examined if low dose POPs predicted future adiposity, dyslipidemia, and insulin resistance among controls without diabetes in that study.The 90 controls were diabetes-free during 20 years follow-up. They were a stratified random sample, enriched with overweight and obese persons. POPs measured in 1987-88 (year 2 sera included 8 organochlorine (OC pesticides, 22 polychlorinated biphenyls (PCBs, and 1 polybrominated biphenyl (PBB. Body mass index (BMI, triglycerides, HDL-cholesterol, LDL-cholesterol, and homeostasis model assessment value for insulin resistance (HOMA-IR were study outcomes at 2005-06 (year 20. The evolution of study outcomes during 18 years by categories of serum concentrations of POPs at year 2 was evaluated by adjusting for the baseline values of outcomes plus potential confounders. Parallel to prediction of type 2 diabetes, many statistically significant associations of POPs with dysmetabolic conditions appeared at low dose, forming inverted U-shaped dose-response relations. Among OC pesticides, p,p'-DDE most consistently predicted higher BMI, triglycerides, and HOMA-IR and lower HDL-cholesterol at year 20 after adjusting for baseline values. Oxychlordane, trans-nonachlor, and hexachlorobenzene also significantly predicted higher triglycerides. Persistent PCBs with ≥7 chlorides predicted higher BMI, triglycerides, and HOMA-IR and lower HDL-cholesterol at year 20 with similar dose-response curves.Simultaneous exposure to various POPs in the general population may contribute to development of obesity, dyslipidemia, and insulin resistance, common precursors of type 2 diabetes and cardiovascular diseases
7. Distribution, historical trends and inventories of polychlorinated biphenyls in sediments from Yangtze River Estuary and adjacent East China Sea
International Nuclear Information System (INIS)
Yang Huayun; Zhuo Shanshan; Xue Bin; Zhang Chunlong; Liu Weiping
2012-01-01
A large portion of polychlorinated biphenyls (PCBs) from e-waste released into the coastal areas may be the potential source of PCBs to the global oceans. The paper presents data of PCBs concentrations in fifty surface sediment samples and a dated sediment core in Yangtze River Delta (YRE) and adjacent East China Sea (ECS). The total PCBs levels varied from 5.08 to 19.64 ng/g dry weight, with the highest concentrations situate within the river-sea boundary zone which is so-called “marginal filter”. Concurrent with the operation of e-waste recycling over the last two decades, PCB fluxes started to rise again after 1980s and reached a maximum in this century. The full data set was used to estimate the burden of PCBs in YRE and adjacent ECS. A total sediment burdens were 192.8 tons, with the spatial density of 364 ng/cm 2 which accounts for 1.9% of all the PCBs in China. - Highlights: ► PCBs residues remained widespread in Yangtze River Delta and adjacent East China Sea. ► Highest PCBs concentrations situate within the river-sea boundary zone. ► Congener profiles and PCA highlight the influence of e-waste recycling. ► Temporal distributions indicated PCB fluxes reached a maximum in this century. ► Total sediment burdens accounts for 1.9 % of all the PCBs in China. - Spatial and temporal distributions of polychlorinated biphenyls have been delineated in sediments from Yangtze River Estuary and adjacent East China Sea.
8. Dioxins, furans, biphenyls, arsenic, thorium and uranium in natural and anthropogenic sources of phosphorus and calcium used in agriculture
Energy Technology Data Exchange (ETDEWEB)
Avelar, A.C., E-mail: avelara@ufmg.br [Department of Animal Sciences, Veterinary School, Universidad de Federal de Minas Gerais Avenida Antonio Carlos, 6627 Campus UFMG, Belo Horizonte (Brazil); Ferreira, W.M. [Department of Animal Sciences, Veterinary School, Universidad de Federal de Minas Gerais Avenida Antonio Carlos, 6627 Campus UFMG, Belo Horizonte (Brazil); Pemberthy, D. [Spanish Council for Scientific Research (CSIC), Institute of Environmental Assessment and Water Research, C/ Jordi Girona 18-26, 08034 Barcelona (Spain); Universidad de Antioquia, Departamento de Ingeniería Química, Facultad de Ingeniería, Grupo Catálisis Ambiental, Calle 70 No. 52-2, Medellín (Colombia); Abad, E. [Spanish Council for Scientific Research (CSIC), Institute of Environmental Assessment and Water Research, C/ Jordi Girona 18-26, 08034 Barcelona (Spain); Amaral, M.A. [Department of Animal Sciences, Veterinary School, Universidad de Federal de Minas Gerais Avenida Antonio Carlos, 6627 Campus UFMG, Belo Horizonte (Brazil)
2016-05-01
The aim of this study was to assess the presence of dioxins, furans and biphenyls, and the inorganic contaminants such as arsenic (As), thorium (Th) and uranium (U) in three main products used in Agriculture in Brazil: feed grade dicalcium phosphate, calcined bovine bone meal and calcitic limestone. The first two are anthropogenic sources of phosphorus and calcium, while calcitic limestone is a natural unprocessed mineral. Regarding to dioxin-like substances, all samples analyzed exhibited dioxins (PCDD) and furans (PCDF) and dioxin-like polychlorinated biphenyls (dl-PCBs) concentrations below limit of detection (LOD). In general, achieved is in accordance with regulation in Brazil where is established a maximum limit in limestone used in the citric pulp production (0.50 pg WHO-TEQ g{sup −1}). In addition, reported data revealed very low levels for limestone in comparison with similar materials reported by European legislation. As result for toxic metals, achieved data were obtained using Instrumental Neutron Activation Analysis (INAA). On one hand, limestone sample exhibits the largest arsenic concentration. On another hand, dicalcium phosphate exhibited the largest uranium concentration, which represents a standard in animal nutrition. Therefore, it is phosphorus source in the animal feed industry can be a goal of concern in the feed field. - Highlights: • PCDD/Fs dl- PCBs is not a matter since levels below the LOD in phosphate materials subject of study. • Significant accumulation of As and U in Limestone. Th was originally found in dicalcium phosphate. • High concentration of U in dicalcium phosphate suggests that a special attention should be paid.
9. Exposure to polychlorinated biphenyls and the thyroid gland - examining and discussing possible longitudinal health effects in humans.
Science.gov (United States)
Gaum, Petra M; Lang, Jessica; Esser, André; Schettgen, Thomas; Neulen, Joseph; Kraus, Thomas; Gube, Monika
2016-07-01
Many previous studies have dealt with the effect of polychlorinated biphenyls (PCBs) on the thyroid gland, but their findings are inconsistent. One problem of these studies has been their use of cross-sectional designs. The aim of the current study is to investigate longitudinal effects of PCBs on the thyroid gland, focusing on: morphological changes in thyroid tissue (i.e. thyroid volume), changes in thyroid hormones and in thyroid antibodies. A total of 122 individuals (Mage=44.7) were examined over a period of four years (t(1) until t(4)). Medical history was collected via interviews, an ultrasound examination was performed and blood samples were taken to determine plasma PCB levels, thyroid stimulating hormone (TSH), free triiodthyronine (fT3), free thyroxine (fT4), thyroid peroxidase antibodies (TPOab), thyreoglobulin antibodies (TGab) and thyroid-stimulating hormone receptor antibodies (TSHRab). Rank correlation coefficients and mixed effect models were performed controlling for age and total lipids. There were negative correlations between higher chlorinated biphenyls and fT3, cross-sectionally as well as longitudinally. We also found an interaction effect of higher-chlorinated PCBs over time for fT4 as well as TSHRab. In case of high exposure, a decrease in fT4 and an increase in TSHRab level were found over time. In regards to the other variables, our findings yielded no clear results in the examined time period. This is the first study to shows a PCB-related effect on fT3, fT4 and TSHRab over a four year period. The data also suggest that morphological and antibody findings remain inconsistent and do not allow for unambiguous interpretation. Copyright © 2016 Elsevier Inc. All rights reserved.
10. Combined impact of lead, cadmium, polychlorinated biphenyls and non-chemical risk factors on blood pressure in NHANES
International Nuclear Information System (INIS)
Peters, Junenette L.; Patricia Fabian, M.; Levy, Jonathan I.
2014-01-01
11. Combined impact of lead, cadmium, polychlorinated biphenyls and non-chemical risk factors on blood pressure in NHANES
Energy Technology Data Exchange (ETDEWEB)
Peters, Junenette L., E-mail: petersj@bu.edu; Patricia Fabian, M., E-mail: pfabian@bu.edu; Levy, Jonathan I., E-mail: jonlevy@bu.edu
2014-07-15
12. Compound semiconductor device modelling
CERN Document Server
Miles, Robert
1993-01-01
Compound semiconductor devices form the foundation of solid-state microwave and optoelectronic technologies used in many modern communication systems. In common with their low frequency counterparts, these devices are often represented using equivalent circuit models, but it is often necessary to resort to physical models in order to gain insight into the detailed operation of compound semiconductor devices. Many of the earliest physical models were indeed developed to understand the 'unusual' phenomena which occur at high frequencies. Such was the case with the Gunn and IMPATI diodes, which led to an increased interest in using numerical simulation methods. Contemporary devices often have feature sizes so small that they no longer operate within the familiar traditional framework, and hot electron or even quantum mechanical models are required. The need for accurate and efficient models suitable for computer aided design has increased with the demand for a wider range of integrated devices for operation at...
13. Simultaneous quantification of T4, T3, rT3, 3,5-T2 and 3,3'-T2 in larval zebrafish (Danio rerio) as a model to study exposure to polychlorinated biphenyls.
Science.gov (United States)
Chen, Xiaopeng; Walter, Kyla M; Miller, Galen W; Lein, Pamela J; Puschner, Birgit
2018-06-01
Environmental toxicants that interfere with thyroid hormone (TH) signaling can impact growth and development in animals and humans. Zebrafish represent a model to study chemically induced TH disruption, prompting the need for sensitive detection of THs. Simultaneous quantification of 3,3',5-triiodo-l-thyronine (T3), thyroxine (T4), 3,3',5'-triiodo-l-thyronine (rT3), 3,5-diiodo-l-thyronine (3,5-T2) and 3,3'-diiodo-l-thyronine (3,3'-T2) in zebrafish larvae was achieved by ultra-performance liquid chromatography-tandem mass spectrometry in positive ion mode. Solid-phase extraction with SampliQ cartridges and derivatization with 3 m hydrochloric acid in n-butanol reduced matrix effects. Derivatized compounds were separated on an Acquity UPLC BEH C 18 column with mobile phases consisting of 0.1% acetic acid in deionized water and 0.1% acetic acid in methanol. The limits of detection ranged from 0.5 to 0.6 pg injected on column. The method was validated by evaluating recovery (77.1-117.2%), accuracy (87.3-123.9%) and precision (0.5-12.4%) using diluted homogenized zebrafish embryos spiked with all target compounds. This method was then applied to zebrafish larvae collected after 114 h of exposure to polychlorinated biphenyls (PCBs), including PCB 28, PCB 66 and PCB 95, or the technical mixture Aroclor 1254. Exposure to PCB 28 and PCB 95 increased the T4:T3 ratio and decreased the T3:rT3 ratio, demonstrating that this method can effectively detect PCB-induced alterations in THs. Copyright © 2018 John Wiley & Sons, Ltd.
14. Simultaneous analysis of organochlorine pesticides and polychlorinated biphenyls in air samples by using accelerated solvent extraction (ASE) and solid-phase micro-extraction (SPME) coupled to gas chromatography dual electron capture detection.
Science.gov (United States)
Mokbel, Haifaa; Al Dine, Enaam Jamal; Elmoll, Ahmad; Liaud, Céline; Millet, Maurice
2016-04-01
An analytical method associating accelerated solvent extraction (ASE) and solid-phase micro-extraction (SPME) in immersion mode combined with gas chromatography dual electrons capture detectors (SPME-GC-2ECD) has been developed and studied for the simultaneous determination of 19 organochlorine pesticides (OCPs) and 22 polychlorinated biphenyls (PCBs) in air samples (active and XAD-2 passive samplers). Samples were extracted with ASE with acetonitrile using the following conditions: temperature, 150 °C; pressure, 1500 psi; static, 15 min; cycles, 3; purge, 300 s; flush, 100 %. Extracts were reduced to 1 mL, and 500 μL of this extract, filled with deionised water, was subject to SPME extraction. Experimental results indicated that the proposed method attained the best extraction efficiency under the optimised conditions: extraction of PCB-OCP mixture using 100-μm PDMS fibre at 80 °C for 40 min with no addition of salt. The performance of the proposed ASE-SPME-GC-2ECD methodology with respect to linearity, limit of quantification and detection was evaluated by spiking of XAD-2 resin with target compounds. The regression coefficient (R (2)) of most compounds was found to be high of 0.99. limits of detection (LODs) are between 0.02 and 4.90 ng m(-3), and limits of quantification (LOQs) are between 0.05 and 9.12 ng m(-3) and between 0.2 and 49 ng/sampler and 0.52 and 91 ng/sampler, respectively, for XAD-2 passive samplers. Finally, a developed procedure was applied to determine selected PCBs and OCPs in the atmosphere.
15. Tripolar Mesoionic Compounds
OpenAIRE
Shuki, Araki; Jiro, Mizuya; Naomitsu, Aoyama; Yasuo, Butsugan
1995-01-01
Tripolar mesoionic compounds have been synthesized by the reaction of (1,3-diphenyltetrazol-5-ylio)cyclopentadienide (or -indenide) with the dicationic ether salts derived from mesoionic olates and trifluoromethanesulfonic anhydride. The structures of the newly prepared mesoionic systems are discussed on the basis of spectroscopic analysis; it is shown that the tripolar [tetrazolium-cyclopentadienide (or indenide)-tetrazolium] canonical structure contributes significantly to the ground state ...
16. Oligosilanylated Antimony Compounds
OpenAIRE
Zitz, Rainer; Gatterer, Karl; Reinhold, Crispin R. W.; M?ller, Thomas; Baumgartner, Judith; Marschner, Christoph
2015-01-01
By reactions of magnesium oligosilanides with SbCl3, a number of oligosilanylated antimony compounds were obtained. When oligosilanyl dianions were used, either the expected cyclic disilylated halostibine was obtained or alternatively the formation of a distibine was observed. Deliberate formation of the distibine from the disilylated halostibine was achieved by reductive coupling with C8K. Computational studies of Sb?Sb bond energies, barriers of pyramidal inversion at Sb, and the conformati...
17. Labelled compounds. (Pt. B)
International Nuclear Information System (INIS)
Buncel, E.; Jones, J.R.
1991-01-01
Since the end of World War II there has been a tremendous increase in the number of compounds that have been synthesized with radioactive or stable isotopes. They have found application in many diverse fields, so much so, that hardly a single area in pure and applied science has not benefited. Not surprisingly it has been reflected in appearance of related publications. The early proceedings of the Symposia on Advances in Trace Methodology were soon followed by various Euratom sponsored meetings in which methods of preparing and storing labelled compounds featured prominently. In due course a resurgence of interest in stable isotopes, brought about by their greater availability (also lower cost) and partly by development of new techniques such as gas chromatography - mass spectrometry (gc-ms), led to the publication of proceedings of several successful conferences. More recently conferences dealing with the synthesis and applications of isotopes and isotopically labelled compounds have been established on a regular basis. In addition to the proceedings of conferences and journal publications individuals left their mark by producing definitive texts, usually on specific nuclides. Only the classic two volume publication of Murray and Williams (Organic syntheses with isotopes, New York 1985), now over 30 years old and out of print, attempted to do justice to several nuclides. With the large amount of work that has been undertaken since then it seems unlikely that an updated edition could be produced. The alternative strategy was to ask scientists currently active to review specific areas and this is the approach adopted in the present series of monographs. In this way it is intended to cover the broad advances that have been made in the synthesis and applications of isotopes and isotopically labelled compounds in the physical and biomedical sciences. (author). refs.; figs.; tabs
18. Process for compound transformation
KAUST Repository
Basset, Jean-Marie
2016-12-29
Embodiments of the present disclosure provide for methods of using a catalytic system to chemically transform a compound (e.g., a hydrocarbon). In an embodiment, the method does not employ grafting the catalyst prior to catalysis. In particular, embodiments of the present disclosure provide for a process of hydrocarbon (e.g., C1 to C20 hydrocarbon) metathesis (e.g., alkane, olefin, or alkyne metathesis) transformation, where the process can be conducted without employing grafting prior to catalysis.
International Nuclear Information System (INIS)
Kim, Y. K.; Park, S. H.; Lee, W. G.; Ha, J. H.
2005-01-01 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6226341724395752, "perplexity": 16769.212095567993}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-51/segments/1575541297626.61/warc/CC-MAIN-20191214230830-20191215014830-00340.warc.gz"} |
http://www.forensicswiki.org/w/index.php?title=RegXML&diff=12826&oldid=9949 | # Difference between revisions of "RegXML"
RegXML is an XML syntax analogous to Digital Forensics XML. It represents the contents of a Windows Registry hive file, presenting key and value cells of the hive as file and directories of a file system.
## Disambiguation
Please note that RegXML is *also* the name of a Windows command-line utility that exports sections of the Windows Registry as XML-formatted files. That program was released on Softpedia. It is a completely separate effort from RegXML otherwise mentioned in this article.
## Sample XML
This RegXML is a sample of the System hive from the M57-Patents scenario, image Charlie 2009-11-16. Its structure is of the first version of RegXML, a deep-hierarchy structure created by extending the Hivexml utility.
```<?xml version="1.0" encoding="UTF-8"?>
<hive>
<mtime>2009-11-17T00:33:57Z</mtime>
<node name="\$\$\$PROTO.HIV" root="1">
<mtime>2009-11-13T04:47:33Z</mtime>
<byte_runs>
<byte_run file_offset="4128" len="92"/>
</byte_runs>
<node name="ControlSet002">
<mtime>2009-11-09T01:26:39Z</mtime>
<byte_runs>
<byte_run file_offset="1480856" len="93"/>
</byte_runs>
<node name="Control">
<mtime>2009-11-13T04:48:01Z</mtime>
<byte_runs>
<byte_run file_offset="1481240" len="87"/>
</byte_runs>
<value type="string" key="WaitToKillServiceTimeout" value="20000">
<byte_runs>
<byte_run file_offset="1481328" len="48"/>
<byte_run file_offset="13448" len="16"/>
</byte_runs>
</value>
<value type="string" key="SystemStartOptions" value="NOEXECUTE=OPTIN FASTDETECT">
<byte_runs>
<byte_run file_offset="1481464" len="42"/>
<byte_run file_offset="3006752" len="60"/>
</byte_runs>
</value>
<value type="string" key="SystemBootDevice" value="multi(0)disk(0)rdisk(0)partition(1)">
<byte_runs>
<byte_run file_offset="3006856" len="40"/>
<byte_run file_offset="3206056" len="76"/>
</byte_runs>
</value>
<node name="Windows">
<mtime>2009-11-13T03:08:00Z</mtime>
<byte_runs>
<byte_run file_offset="2355232" len="87"/>
</byte_runs>
<value type="expand" key="SystemDirectory" value="%SystemRoot%\system32">
<byte_runs>
<byte_run file_offset="2355368" len="39"/>
<byte_run file_offset="3111128" len="48"/>
</byte_runs>
</value>
<value type="binary" encoding="base64" key="ShutdownTime" value="RDGhgQ5kygE=">
<byte_runs>
<byte_run file_offset="3203784" len="36"/>
<byte_run file_offset="1481592" len="12"/>
</byte_runs>
</value>
</node>
<node name="WOW">
<mtime>2009-11-09T01:22:59Z</mtime>
<byte_runs>
<byte_run file_offset="2359096" len="83"/>
</byte_runs>
<value type="expand" key="cmdline" value="%SystemRoot%\system32\ntvdm.exe">
<byte_runs>
<byte_run file_offset="2358720" len="31"/>
<byte_run file_offset="2359184" len="68"/>
</byte_runs>
</value>
<value type="string" key="KnownDLLs" value="comm.drv commdlg.dll ctl3dv2.dll ddeml.dll
keyboard.drv lanman.drv mmsystem.dll mouse.drv netapi.dll olecli.dll olesvr.dll pmspl.dll shell.dll
sound.drv system.drv toolhelp.dll vga.drv wfwnet.drv win87em.dll winoldap.mod winsock.dll
winspool.exe wowdeb.exe timer.drv rasapi16.dll compobj.dll storage.dll ole2.dll ole2disp.dll
ole2nls.dll typelib.dll msvideo.dll avifile.dll msacm.dll mciavi.drv mciseq.drv mciwave.drv
progman.exe avicap.dll mapi.dll">
<byte_runs>
<byte_run file_offset="2359256" len="33"/>
<byte_run file_offset="2361648" len="904"/>
</byte_runs>
</value>
</node>
</node>
</node>
</node>
</hive>
``` | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8012872338294983, "perplexity": 6690.791103772974}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-32/segments/1438042987155.85/warc/CC-MAIN-20150728002307-00143-ip-10-236-191-2.ec2.internal.warc.gz"} |
https://www.math.ias.edu/seminars/abstract?event=122405 | # Discrete harmonic analysis and applications to ergodic theory
Analysis Math-Physics Seminar Topic: Discrete harmonic analysis and applications to ergodic theory Speaker: Mariusz Mirek Affiliation: University of Bonn; Member, School of Mathematics Date: Wednesday, February 8 Time/Room: 1:30pm - 2:30pm/S-101 Video Link: https://video.ias.edu/analysismathphysics/2017/0208-MariuszMirek
Given $d, k\in\mathbb N$, let $P_j$ be an integer-valued polynomial of $k$ variables for every $1\le j \le d$. Suppose that $(X, \mathcal{B}, \mu)$ is a $\sigma$-finite measure space with a family of invertible commuting and measure preserving transformations $T_1, T_2,\ldots,T_{d}$ on $X$. For every $N\in\mathbb N$ and $x \in X$ we define the ergodic Radon averaging operators by setting $A_N f(x) = \frac{1}{N^{k}}\sum_{m \in [1, N]^k\cap\mathbb Z^k} f\big(T_1^{ P_1(m)}\circ T_2^{ P_2(m)} \circ \ldots \circ T_{d}^{ P_{d}(m)} x\big).$ We will show that for every $p > 1$ and for every function $f \in L^p(X, \mu)$, there is a function $f^*\in L^p(X, \mu)$ such that $\lim_{N\to\infty}A_Nf(x)=f^*(x)$ $\mu$-almost everywhere on $X$. We will achieve this by considering $r$-variational estimates. This is a joint work with Elias M. Stein and Bartosz Trojan. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 2, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9241738319396973, "perplexity": 369.3283594419699}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-13/segments/1521257646636.25/warc/CC-MAIN-20180319081701-20180319101701-00166.warc.gz"} |
https://link.springer.com/chapter/10.1007%2F978-3-030-01090-4_20 | # A Fragment of Linear Temporal Logic for Universal Very Weak Automata
• Rüdiger Ehlers
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 11138)
## Abstract
Many temporal specifications used in practical model checking can be represented as universal very weak automata (UVW). They are structurally simple and their states can be labeled by simple temporal logic formulas that they represent. For complex temporal properties, it can be hard to understand why a trace violates a property, so when employing UVWs in model checking, this information helps with interpreting the trace. At the same time, the simple structure of UVWs helps the model checker with finding short traces.
While a translation from computation tree logic (CTL) with only universal path quantifiers to UVWs has been described in earlier work, complex temporal properties that define sequences of allowed events along computations of a system are easier to describe in linear temporal logic (LTL). However, no direct translation from LTL to UVWs with little blow-up is known.
In this paper, we define a fragment of LTL that gives rise to a simple and efficient translation from it to UVW. The logic contains the most common shapes of safety and liveness properties, including all nestings of “Until”-subformulas. We give a translation from this fragment to UVWs that only has an exponential blow-up in the worst case, which we show to be unavoidable. We demonstrate that the simple shape of UVWs helps with understanding counter-examples in a case study.
## References
1. 1.
Pnueli, A.: The temporal logic of programs. In: Proceedings of the 18th IEEE FOCS, pp. 46–57 (1977)Google Scholar
2. 2.
Clarke, E.M., Grumberg, O., Peled, D.: Model Checking. MIT Press, Cambridge (1999)Google Scholar
3. 3.
Blahoudek, F., Duret-Lutz, A., Kretínský, M., Strejcek, J.: Is there a best Büchi automaton for explicit model checking? In: SPIN Symposium, pp. 68–76 (2014)Google Scholar
4. 4.
Beer, I., Ben-David, S., Chockler, H., Orni, A., Trefler, R.J.: Explaining counterexamples using causality. Form. Methods Syst. Des. 40(1), 20–40 (2012)
5. 5.
Basin, D., Bhatt, B.N., Traytel, D.: Optimal proofs for linear temporal logic on lasso words. In: 16th International Symposium on Automated Technology for Verification and Analysis (ATVA 2018) (2018)Google Scholar
6. 6.
Maidl, M.: The common fragment of CTL and LTL. In: Proceedings of the 41st Annual Symposium on Foundations of Computer Science (FOCS), pp. 643–652 (2000)Google Scholar
7. 7.
Ehlers, R.: ACTL $$\cap$$ LTL synthesis. In: Madhusudan, P., Seshia, Sanjit A. (eds.) CAV 2012. LNCS, vol. 7358, pp. 39–54. Springer, Heidelberg (2012).
8. 8.
Holzmann, G.J.: The SPIN Model Checker - Primer and Reference Manual. Addison-Wesley, Menlo Park (2004)Google Scholar
9. 9.
Cichon, J., Czubak, A., Jasinski, A.: Minimal Büchi automata for certain classes of LTL formulas. In: Fourth International Conference on Dependability of Computer Systems, (DepCos-RELCOMEX), pp. 17–24 (2009)Google Scholar
10. 10.
Gurumurthy, S., Bloem, R., Somenzi, F.: Fair simulation minimization. In: Brinksma, E., Larsen, K.G. (eds.) CAV 2002. LNCS, vol. 2404, pp. 610–623. Springer, Heidelberg (2002).
11. 11.
Vardi, M.Y.: Nontraditional applications of automata theory. In: Hagiya, M., Mitchell, J.C. (eds.) TACS 1994. LNCS, vol. 789, pp. 575–597. Springer, Heidelberg (1994).
12. 12.
Gerth, R., Peled, D.A., Vardi, M.Y., Wolper, P.: Simple on-the-fly automatic verification of linear temporal logic. In: Protocol Specification, Testing and Verification XV, pp. 3–18 (1995)
13. 13.
Ehlers, R.: Short witnesses and accepting lassos in $$\omega$$-automata. In: Dediu, A.-H., Fernau, H., Martín-Vide, C. (eds.) LATA 2010. LNCS, vol. 6031, pp. 261–272. Springer, Heidelberg (2010).
14. 14.
Bojańczyk, M.: The common fragment of ACTL and LTL. In: Amadio, R. (ed.) FoSSaCS 2008. LNCS, vol. 4962, pp. 172–185. Springer, Heidelberg (2008).
15. 15.
Duret-Lutz, A.: LTL translation improvements in Spot 1.0. Int. J. Crit. Comput. Based Syst. 5(1/2), 31–54 (2014)
16. 16.
Kamel, M., Leue, S.: Validation of a remote object invocation and object migration in CORBA GIOP using Promela/Spin. In: International SPIN Workshop (1998)Google Scholar
17. 17.
Filiot, E., Jin, N., Raskin, J.: Antichains and compositional algorithms for LTL synthesis. Form. Methods Syst. Des. 39(3), 261–296 (2011)
18. 18.
Finkbeiner, B., Schewe, S.: Bounded synthesis. STTT 15(5–6), 519–539 (2013) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9502578973770142, "perplexity": 14016.002167387927}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-04/segments/1610704833804.93/warc/CC-MAIN-20210127214413-20210128004413-00513.warc.gz"} |