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https://en.wikipedia.org/wiki/Construction%20grammar | Construction grammar (often abbreviated CxG) is a family of theories within the field of cognitive linguistics which posit that constructions, or learned pairings of linguistic patterns with meanings, are the fundamental building blocks of human language. Constructions include words (aardvark, avocado), morphemes (anti-, -ing), fixed expressions and idioms (by and large, jog X's memory), and abstract grammatical rules such as the passive voice (The cat was hit by a car) or the ditransitive (Mary gave Alex the ball). Any linguistic pattern is considered to be a construction as long as some aspect of its form or its meaning cannot be predicted from its component parts, or from other constructions that are recognized to exist. In construction grammar, every utterance is understood to be a combination of multiple different constructions, which together specify its precise meaning and form.
Advocates of construction grammar argue that language and culture are not designed by people, but are 'emergent' or automatically constructed in a process which is comparable to natural selection in species or the formation of natural constructions such as nests made by social insects. Constructions correspond to replicators or memes in memetics and other cultural replicator theories. It is argued that construction grammar is not an original model of cultural evolution, but for essential part the same as memetics. Construction grammar is associated with concepts from cognitive linguistics that aim to show in various ways how human rational and creative behaviour is automatic and not planned.
History
Construction grammar was first developed in the 1980s by linguists such as Charles Fillmore, Paul Kay, and George Lakoff, in order to analyze idioms and fixed expressions. Lakoff's 1977 paper "Linguistic Gestalts" put forward an early version of CxG, arguing that the meaning of an expression was not simply a function of the meanings of its parts. Instead, he suggested, constructions th |
https://en.wikipedia.org/wiki/Energy%20management%20system | An energy management system (EMS) is a system of computer-aided tools used by operators of electric utility grids to monitor, control, and optimize the performance of the generation or transmission system. Also, it can be used in small scale systems like microgrids.
Terminology
The computer technology is also referred to as SCADA/EMS or EMS/SCADA. In these respects, the terminology EMS then excludes the monitoring and control functions, but more specifically refers to the collective suite of power network applications and to the generation control and scheduling applications.
Manufacturers of EMS also commonly supply a corresponding dispatcher training simulator (DTS). This related technology makes use of components of SCADA and EMS as a training tool for control center operators.
Operating systems
Up to the early 1990s it was common to find EMS systems being delivered based on proprietary hardware and operating systems. Back then EMS suppliers such as Harris Controls (now GE), Hitachi, Cebyc, Control Data Corporation, Siemens and Toshiba manufactured their own proprietary hardware. EMS suppliers that did not manufacture their own hardware often relied on products developed by Digital Equipment, Gould Electronics and MODCOMP. The VAX 11/780 from Digital Equipment was a popular choice amongst some EMS suppliers. EMS systems now rely on a model based approach. Traditional planning models and EMS models were always independently maintained and seldom in synchronism with each other. Using EMS software allows planners and operators to share a common model reducing the mismatch between the two and cutting model maintenance by half. Having a common user interface also allows for easier transition of information from planning to operations.
As proprietary systems became uneconomical, EMS suppliers began to deliver solutions based on industry standard hardware platforms such as those from Digital Equipment (later Compaq (later HP)), IBM and Sun. The common operating syst |
https://en.wikipedia.org/wiki/Mean%20motion | In orbital mechanics, mean motion (represented by n) is the angular speed required for a body to complete one orbit, assuming constant speed in a circular orbit which completes in the same time as the variable speed, elliptical orbit of the actual body. The concept applies equally well to a small body revolving about a large, massive primary body or to two relatively same-sized bodies revolving about a common center of mass. While nominally a mean, and theoretically so in the case of two-body motion, in practice the mean motion is not typically an average over time for the orbits of real bodies, which only approximate the two-body assumption. It is rather the instantaneous value which satisfies the above conditions as calculated from the current gravitational and geometric circumstances of the body's constantly-changing, perturbed orbit.
Mean motion is used as an approximation of the actual orbital speed in making an initial calculation of the body's position in its orbit, for instance, from a set of orbital elements. This mean position is refined by Kepler's equation to produce the true position.
Definition
Define the orbital period (the time period for the body to complete one orbit) as P, with dimension of time. The mean motion is simply one revolution divided by this time, or,
with dimensions of radians per unit time, degrees per unit time or revolutions per unit time.
The value of mean motion depends on the circumstances of the particular gravitating system. In systems with more mass, bodies will orbit faster, in accordance with Newton's law of universal gravitation. Likewise, bodies closer together will also orbit faster.
Mean motion and Kepler's laws
Kepler's 3rd law of planetary motion states, the square of the periodic time is proportional to the cube of the mean distance, or
where a is the semi-major axis or mean distance, and P is the orbital period as above. The constant of proportionality is given by
where μ is the standard gravitational paramet |
https://en.wikipedia.org/wiki/Fernery | A fernery is a specialized garden for the cultivation and display of ferns.
In many countries, ferneries are indoors or at least sheltered or kept in a shadehouse to provide a moist environment, filtered light and protection from frost and other extremes; on the other hand, some ferns native to arid regions require protection from rain and humid conditions, and grow best in full sun. In mild climates, ferneries are often outside and have an array of different species that grow under similar conditions.
In 1855, parts of England were gripped by 'pteridomania' (the fern craze). This term was coined by Charles Kingsley, clergyman, naturalist (and later author of The Water Babies). It involved both British and exotic varieties being collected and displayed; many associated structures were constructed and paraphernalia was used to maintain the collections.
In 1859, the Fernery at Tatton Park Gardens beside Tatton Hall had been built to a design by George Stokes, Joseph Paxton's assistant and son-in-law, to the west of the conservatory to house tree ferns from New Zealand and a collection of other ferns. The Fernery was also seen in the TV miniseries Brideshead Revisited.
In 1874, the fernery in Benmore Botanic Garden (part of the Royal Botanic Garden Edinburgh) was built by James Duncan (a plant collector and sugar refiner). This was a large and expensive project since the fernery was based in a heated conservatory. In 1992, it was listed Historic Scotland for its architectural and botanical value and has been described by the Royal Commission on the Ancient and Historical Monuments of Scotland as "extremely rare and unique in its design".
In 1903, Hever Castle in Kent was acquired and restored by the American millionaire William Waldorf Astor who used it as a family residence. He added the Italian Garden (including a fernery) to display his collection of statuary and ornaments. |
https://en.wikipedia.org/wiki/Secure%20voice | Secure voice (alternatively secure speech or ciphony) is a term in cryptography for the encryption of voice communication over a range of communication types such as radio, telephone or IP.
History
The implementation of voice encryption dates back to World War II when secure communication was paramount to the US armed forces. During that time, noise was simply added to a voice signal to prevent enemies from listening to the conversations. Noise was added by playing a record of noise in sync with the voice signal and when the voice signal reached the receiver, the noise signal was subtracted out, leaving the original voice signal. In order to subtract out the noise, the receiver need to have exactly the same noise signal and the noise records were only made in pairs; one for the transmitter and one for the receiver. Having only two copies of records made it impossible for the wrong receiver to decrypt the signal. To implement the system, the army contracted Bell Laboratories and they developed a system called SIGSALY. With SIGSALY, ten channels were used to sample the voice frequency spectrum from 250 Hz to 3 kHz and two channels were allocated to sample voice pitch and background hiss. In the time of SIGSALY, the transistor had not been developed and the digital sampling was done by circuits using the model 2051 Thyratron vacuum tube. Each SIGSALY terminal used 40 racks of equipment weighing 55 tons and filled a large room. This equipment included radio transmitters and receivers and large phonograph turntables. The voice was keyed to two vinyl phonograph records that contained a Frequency Shift Keying (FSK) audio tone. The records were played on large precise turntables in sync with the voice transmission.
From the introduction of voice encryption to today, encryption techniques have evolved drastically. Digital technology has effectively replaced old analog methods of voice encryption and by using complex algorithms, voice encryption has become much mo |
https://en.wikipedia.org/wiki/Active-set%20method | In mathematical optimization, the active-set method is an algorithm used to identify the active constraints in a set of inequality constraints. The active constraints are then expressed as equality constraints, thereby transforming an inequality-constrained problem into a simpler equality-constrained subproblem.
An optimization problem is defined using an objective function to minimize or maximize, and a set of constraints
that define the feasible region, that is, the set of all x to search for the optimal solution. Given a point in the feasible region, a constraint
is called active at if , and inactive at if Equality constraints are always active. The active set at is made up of those constraints that are active at the current point .
The active set is particularly important in optimization theory, as it determines which constraints will influence the final result of optimization. For example, in solving the linear programming problem, the active set gives the hyperplanes that intersect at the solution point. In quadratic programming, as the solution is not necessarily on one of the edges of the bounding polygon, an estimation of the active set gives us a subset of inequalities to watch while searching the solution, which reduces the complexity of the search.
Active-set methods
In general an active-set algorithm has the following structure:
Find a feasible starting point
repeat until "optimal enough"
solve the equality problem defined by the active set (approximately)
compute the Lagrange multipliers of the active set
remove a subset of the constraints with negative Lagrange multipliers
search for infeasible constraints
end repeat
Methods that can be described as active-set methods include:
Successive linear programming (SLP)
Sequential quadratic programming (SQP)
Sequential linear-quadratic programming (SLQP)
Reduced gradient method (RG)
Generalized reduced gradient method (GRG) |
https://en.wikipedia.org/wiki/Delta%20bond | In chemistry, delta bonds (δ bonds) are covalent chemical bonds, where four lobes of one involved atomic orbital overlap four lobes of the other involved atomic orbital. This overlap leads to the formation of a bonding molecular orbital with two nodal planes which contain the internuclear axis and go through both atoms.
The Greek letter δ in their name refers to d orbitals, since the orbital symmetry of the δ bond is the same as that of the usual (4-lobed) type of d orbital when seen down the bond axis. This type of bonding is observed in atoms that have occupied d orbitals with low enough energy to participate in covalent bonding, for example, in organometallic species of transition metals. Some rhenium, molybdenum, technetium, and chromium compounds contain a quadruple bond, consisting of one σ bond, two π bonds and one δ bond.
The orbital symmetry of the δ bonding orbital is different from that of a π antibonding orbital, which has one nodal plane containing the internuclear axis and a second nodal plane perpendicular to this axis between the atoms.
The δ notation was introduced by Robert Mulliken in 1931. The first compound identified as having a δ bond was potassium octachlorodirhenate(III). In 1965, F. A. Cotton reported that there was δ-bonding as part of the rhenium–rhenium quadruple bond in the [Re2Cl8]2− ion. Another interesting example of a δ bond is proposed in cyclobutadieneiron tricarbonyl between an iron d orbital and the four p orbitals of the attached cyclobutadiene molecule.
See also
Quadruple bond
Phi bond |
https://en.wikipedia.org/wiki/Proof%20of%20work | Proof of work (PoW) is a form of cryptographic proof in which one party (the prover) proves to others (the verifiers) that a certain amount of a specific computational effort has been expended. Verifiers can subsequently confirm this expenditure with minimal effort on their part. The concept was invented by Moni Naor and Cynthia Dwork in 1993 as a way to deter denial-of-service attacks and other service abuses such as spam on a network by requiring some work from a service requester, usually meaning processing time by a computer. The term "proof of work" was first coined and formalized in a 1999 paper by Markus Jakobsson and Ari Juels.
Proof of work was later popularized by Bitcoin as a foundation for consensus in a permissionless decentralized network, in which miners compete to append blocks and mine new currency, each miner experiencing a success probability proportional to the computational effort expended. PoW and PoS (proof of stake) remain the two best known Sybil deterrence mechanisms. In the context of cryptocurrencies they are the most common mechanisms.
A key feature of proof-of-work schemes is their asymmetry: the work – the computation – must be moderately hard (yet feasible) on the prover or requester side but easy to check for the verifier or service provider. This idea is also known as a CPU cost function, client puzzle, computational puzzle, or CPU pricing function. Another common feature is built-in incentive-structures that reward allocating computational capacity to the network with value in the form of cryptocurrency.
The purpose of proof-of-work algorithms is not proving that certain work was carried out or that a computational puzzle was "solved", but deterring manipulation of data by establishing large energy and hardware-control requirements to be able to do so. Proof-of-work systems have been criticized by environmentalists for their energy consumption.
Background
One popular system, used in Hashcash, uses partial hash inversions to p |
https://en.wikipedia.org/wiki/Ralph%20Ernest%20Powers | Ralph Ernest Powers (April 27, 1875 – January 31, 1952) was an American amateur mathematician who worked on prime numbers.
He is credited with discovering the Mersenne primes and , in 1911 and 1914 respectively. In 1934 he verified that the Mersenne number is composite.
Life
Powers was born in Fountain, Colorado Territory. Details of his life are little-known, though he appears to have been an employee of the Denver and Rio Grande Western Railroad.
Soon after Powers announced the discovery of , the Frenchman E. Fauquembergue claimed that he had discovered it earlier, but many of Fauquembergue's other claims were later demonstrated as erroneous; thus, many prefer recognizing Powers as the discoverer, including the well-known Internet resource the PrimePages.
After his own discoveries of Mersenne primes in 1911 and 1914, no Mersenne primes were discovered until Raphael M. Robinson used a computer to find the next two, on January 30, 1952, the night before Powers's death.
Works
‘The Tenth Perfect Number', American Mathematical Monthly, Vol. 18 (1911), pp. 195–7
’On Mersenne's Numbers', Proceedings of the London Mathematical Society, Vol. 13 (1914), p. xxxix
'A Mersenne Prime', Bulletin of the American Mathematical Society, Vol. 20, No. 10 (1914), p. 531
’Certain composite Mersenne's numbers', Proceedings of the London Mathematical Society Vol. 15 (1916), p. xxii
(with D. H. Lehmer) 'On Factoring Large Numbers', Bulletin of the American Mathematical Society, Vol. 37. No. 10 (1931), pp. 770–76
’Note on a Mersenne Number', Bulletin of the American Mathematical Society, Vol. 40, No. 12 (1934), p. 883
See also
Continued fraction factorization |
https://en.wikipedia.org/wiki/Mobile%20QoS | Quality of service (QoS) mechanism controls the performance, reliability and usability of a telecommunications service. Mobile cellular service providers may offer mobile QoS to customers just as the fixed line PSTN services providers and Internet service providers may offer QoS. QoS mechanisms are always provided for circuit switched services, and are essential for non-elastic services, for example streaming multimedia. It is also essential in networks dominated by such services, which is the case in today's mobile communication networks.
Mobility adds complication to the QoS mechanisms, for several reasons:
A phone call or other session may be interrupted after a handover, if the new base station is overloaded. Unpredictable handovers make it impossible to give an absolute QoS guarantee during a session initiation phase.
The pricing structure is often based on per-minute or per-megabyte fee rather than flat rate, and may be different for different content services.
A crucial part of QoS in mobile communications is grade of service, involving outage probability (the probability that the mobile station is outside the service coverage area, or affected by co-channel interference, i.e. crosstalk) blocking probability (the probability that the required level of QoS can not be offered) and scheduling starvation. These performance measures are affected by mechanisms such as mobility management, radio resource management, admission control, fair scheduling, channel-dependent scheduling etc.
Factors affecting QoS
Many factors affect the quality of service of a mobile network. It is correct to look at QoS mainly from the customer's point of view, that is, QoS as judged by the user. There are standard metrics of QoS to the user that can be measured to rate the QoS. These metrics are: the coverage, accessibility (includes GoS), and the audio quality. In coverage the strength of the signal is measured using test equipment and this can be used to estimate the size of the |
https://en.wikipedia.org/wiki/Variance%20swap | A variance swap is an over-the-counter financial derivative that allows one to speculate on or hedge risks associated with the magnitude of movement, i.e. volatility, of some underlying product, like an exchange rate, interest rate, or stock index.
One leg of the swap will pay an amount based upon the realized variance of the price changes of the underlying product. Conventionally, these price changes will be daily log returns, based upon the most commonly used closing price. The other leg of the swap will pay a fixed amount, which is the strike, quoted at the deal's inception. Thus the net payoff to the counterparties will be the difference between these two and will be settled in cash at the expiration of the deal, though some cash payments will likely be made along the way by one or the other counterparty to maintain agreed upon margin.
Structure and features
The features of a variance swap include:
the variance strike
the realized variance
the vega notional: Like other swaps, the payoff is determined based on a notional amount that is never exchanged. However, in the case of a variance swap, the notional amount is specified in terms of vega, to convert the payoff into dollar terms.
The payoff of a variance swap is given as follows:
where:
= variance notional (a.k.a. variance units),
= annualised realised variance, and
= variance strike.
The annualised realised variance is calculated based on a prespecified set of sampling points over the period. It does not always coincide with the classic statistical definition of variance as the contract terms may not subtract the mean. For example, suppose that there are observed prices
where
for to . Define the natural log returns.
Then
where is an annualisation factor normally chosen to be approximately the number of sampling points in a year (commonly 252) and is set be the swaps contract life defined by the number . It can be seen that subtracting the mean return will decrease the realised varianc |
https://en.wikipedia.org/wiki/Lists%20of%20medical%20eponyms | Medical eponyms are terms used in medicine which are named after people (and occasionally places or things). In 1975, the Canadian National Institutes of Health held a conference that discussed the naming of diseases and conditions. This was reported in The Lancet where the conclusion was summarized as: "The possessive use of an eponym should be discontinued, since the author neither had nor owned the disorder."
New discoveries are often attached to the people who made the discovery because of the nature of the history of medicine.
List of eponymous diseases
List of eponymous fractures
List of eponymous medical signs
List of eponymous surgical procedures
List of eponymous tests
List of human anatomical parts named after people
List of eponymous medical devices
List of eponymous medical treatments
List of medical eponyms with Nazi associations
List of orthopaedic eponyms
List of eponyms in neuroscience, neurology and neurosurgery |
https://en.wikipedia.org/wiki/Acoustic%20cryptanalysis | Acoustic cryptanalysis is a type of side channel attack that exploits sounds emitted by computers or other devices.
Most of the modern acoustic cryptanalysis focuses on the sounds produced by computer keyboards and internal computer components, but historically it has also been applied to impact printers, and electromechanical deciphering machines.
History
Victor Marchetti and John D. Marks eventually negotiated the declassification of CIA acoustic intercepts of the sounds of cleartext printing from encryption machines. Technically this method of attack dates to the time of FFT hardware being cheap enough to perform the task; in this case the late 1960s to mid-1970s. However, using other more primitive means such acoustical attacks were made in the mid-1950s.
In his book Spycatcher, former MI5 operative Peter Wright discusses use of an acoustic attack against Egyptian Hagelin cipher machines in 1956. The attack was codenamed "ENGULF".
Known attacks
In 2004, Dmitri Asonov and Rakesh Agrawal of the IBM Almaden Research Center announced that computer keyboards and keypads used on telephones and automated teller machines (ATMs) are vulnerable to attacks based on the sounds produced by different keys. Their attack employed a neural network to recognize the key being pressed. By analyzing recorded sounds, they were able to recover the text of data being entered. These techniques allow an attacker using covert listening devices to obtain passwords, passphrases, personal identification numbers (PINs), and other information entered via keyboards. In 2005, a group of UC Berkeley researchers performed a number of practical experiments demonstrating the validity of this kind of threat.
Also in 2004, Adi Shamir and Eran Tromer demonstrated that it may be possible to conduct timing attacks against a CPU performing cryptographic operations by analyzing variations in acoustic emissions. Analyzed emissions were ultrasonic noise emanating from capacitors and inductors on co |
https://en.wikipedia.org/wiki/Color%20balance | In photography and image processing, color balance is the global adjustment of the intensities of the colors (typically red, green, and blue primary colors). An important goal of this adjustment is to render specific colors – particularly neutral colors like white or grey – correctly. Hence, the general method is sometimes called gray balance, neutral balance, or white balance. Color balance changes the overall mixture of colors in an image and is used for color correction. Generalized versions of color balance are used to correct colors other than neutrals or to deliberately change them for effect. White balance is one of the most common kinds of balancing, and is when colors are adjusted to make a white object (such as a piece of paper or a wall) appear white and not a shade of any other colour.
Image data acquired by sensors – either film or electronic image sensors – must be transformed from the acquired values to new values that are appropriate for color reproduction or display. Several aspects of the acquisition and display process make such color correction essential – including that the acquisition sensors do not match the sensors in the human eye, that the properties of the display medium must be accounted for, and that the ambient viewing conditions of the acquisition differ from the display viewing conditions.
The color balance operations in popular image editing applications usually operate directly on the red, green, and blue channel pixel values, without respect to any color sensing or reproduction model. In film photography, color balance is typically achieved by using color correction filters over the lights or on the camera lens.
Generalized color balance
Sometimes the adjustment to keep neutrals neutral is called white balance, and the phrase color balance refers to the adjustment that in addition makes other colors in a displayed image appear to have the same general appearance as the colors in an original scene. It is particularly import |
https://en.wikipedia.org/wiki/Game%20client | A game client is a network client that connects an individual user to the main game server, used mainly in multiplayer video games. It collects data such as score, player status, position and movement from a single player and send it to the game server, which allows the server to collect each individual's data and show every player in game, whether it is an arena game on a smaller scale or a massive game with thousands of players on the same map. Even though the game server displays each player's information for every player in a game, players still have their own unique perspective from the information collected by the game client, so that every player's perspective of the game is different, even though the world for every player is the same. The game client also allows the information sharing among users. An example would be item exchange in many MMORPG games where a player exchange an item he/she doesn't want for an item he/she wants, the game clients interconnect with each other and allows the sharing of information, in this exchanging items. Since many games requires a centralized space for players to gather and a way for users to exchange their information, many game clients are a hybrid of client-server and peer-to-peer application structures.
History
The World Wide Web was born on a NeXTCube with a 256Mhz cpu, 2GB of disk, and a gray scale monitor running NeXTSTEP OS. Sir Tim Berners-Lee put the first web page online on August 6, 1991, while working for CERN in Geneva Switzerland. Online gaming started in the early seventies. At that time Dial-up bulletin boards provided players with a way of playing games over the internet. In the 1990s, new technologies enabled gaming sites to pop up all over the internet. The client-server system provided online gaming a way to function on a large scale.
Functions
A game client has 4 primary functions: Receive inputs, Analyzes data, Gives feedback, Adjust system
Receives input
A game client receives input from an in |
https://en.wikipedia.org/wiki/Statewatch | Statewatch is a non-profit organization founded in 1991 that monitors civil liberties and other issues in the European Union and encourages investigative reporting and research.
The organization has three free databases: a large database of all its news, articles and links since 1991, the Statewatch European Monitoring and Documentation Centre (SEMDOC) which monitors all new justice and home affairs measures since 1993.
The predecessor to Statewatch was "State Research" (1977-1982), which produced a bi-monthly bulletin and carried research.
Among other activities, it monitors anti-terrorist legislation, has a Passenger Name Record observatory, is concerned about asylum issues, data privacy, biometrics, etc.
The organization and its director, Tony Bunyan, have received awards for their civil rights activism including a 1998 award from the British Campaign for Freedom of Information and the 2011 "Long Walk" award at the Liberty's Human Rights Awards. |
https://en.wikipedia.org/wiki/Principles%20and%20Standards%20for%20School%20Mathematics | Principles and Standards for School Mathematics (PSSM) are guidelines produced by the National Council of Teachers of Mathematics (NCTM) in 2000, setting forth recommendations for mathematics educators. They form a national vision for preschool through twelfth grade mathematics education in the US and Canada. It is the primary model for standards-based mathematics.
The NCTM employed a consensus process that involved classroom teachers, mathematicians, and educational researchers. The resulting document sets forth a set of six principles (Equity, Curriculum, Teaching, Learning, Assessment, and Technology) that describe NCTM's recommended framework for mathematics programs, and ten general strands or standards that cut across the school mathematics curriculum. These strands are divided into mathematics content (Number and Operations, Algebra, Geometry, Measurement, and Data Analysis and Probability) and processes (Problem Solving, Reasoning and Proof, Communication, Connections, and Representation). Specific expectations for student learning are described for ranges of grades (preschool to 2, 3 to 5, 6 to 8, and 9 to 12).
Origins
The Principles and Standards for School Mathematics was developed by the NCTM. The NCTM's stated intent was to improve mathematics education. The contents were based on surveys of existing curriculum materials, curricula and policies from many countries, educational research publications, and government agencies such as the U.S. National Science Foundation. The original draft was widely reviewed at the end of 1998 and revised in response to hundreds of suggestions from teachers.
The PSSM is intended to be "a single resource that can be used to improve mathematics curricula, teaching, and assessment." The latest update was published in 2000. The PSSM is available as a book, and in hypertext format on the NCTM web site.
The PSSM replaces three prior publications by NCTM:
Curriculum and Evaluation Standards for School Mathematics (1 |
https://en.wikipedia.org/wiki/National%20Council%20of%20Teachers%20of%20Mathematics | Founded in 1920, The National Council of Teachers of Mathematics (NCTM) is a professional organization for schoolteachers of mathematics in the United States. One of its goals is to improve the standards of mathematics in education. NCTM holds annual national and regional conferences for teachers and publishes five journals.
Journals
NCTM publishes five official journals. All are available in print and online versions.
Teaching Children Mathematics supports improvement of pre-K–6 mathematics education by serving as a resource for teachers so as to provide more and better mathematics for all students. It is a forum for the exchange of mathematics idea, activities, and pedagogical strategies, and or sharing and interpreting research.
Mathematics Teaching in the Middle School supports the improvement of grade 5–9 mathematics education by serving as a resource for practicing and prospective teachers, as well as supervisors and teacher educators. It is a forum for the exchange of mathematics idea, activities, and pedagogical strategies, and or sharing and interpreting research.
Mathematics Teacher is devoted to improving mathematics instruction for grades 8–14 and supporting teacher education programs. It provides a forum for sharing activities and pedagogical strategies, deepening understanding of mathematical ideas, and linking mathematical education research to practice.
Mathematics Teacher Educator, published jointly with the Association of Mathematics Teacher Educators, contributes to building a professional knowledge base for mathematics teacher educators that stems from, develops, and strengthens practitioner knowledge. The journal provides a means for practitioner knowledge related to the preparation and support of teachers of mathematics to be not only public, shared, and stored, but also verified and improved over time (Hiebert, Gallimore, and Stigler 2002).
NCTM does not conduct research in mathematics education, but it does publish the Journal for Rese |
https://en.wikipedia.org/wiki/Curie%E2%80%93Weiss%20law | In magnetism, the Curie–Weiss law describes the magnetic susceptibility of a ferromagnet in the paramagnetic region above the Curie temperature:
where is a material-specific Curie constant, is the absolute temperature, and is the Curie temperature, both measured in kelvin. The law predicts a singularity in the susceptibility at . Below this temperature, the ferromagnet has a spontaneous magnetization. The name is given after Pierre Curie and Pierre Weiss.
Background
A magnetic moment which is present even in the absence of the external magnetic field is called spontaneous magnetization. Materials with this property are known as ferromagnets, such as iron, nickel, and magnetite. However, when these materials are heated up, at a certain temperature they lose their spontaneous magnetization, and become paramagnetic. This threshold temperature below which a material is ferromagnetic is called the Curie temperature and is different for each material.
The Curie–Weiss law describes the changes in a material's magnetic susceptibility, , near its Curie temperature. The magnetic susceptibility is the ratio between the material's magnetization and the applied magnetic field.
Limitations
In many materials, the Curie–Weiss law fails to describe the susceptibility in the immediate vicinity of the Curie point, since it is based on a mean-field approximation. Instead, there is a critical behavior of the form
with the critical exponent . However, at temperatures the expression of the Curie–Weiss law still holds true, but with replaced by a temperature that is somewhat higher than the actual Curie temperature. Some authors call the Weiss constant to distinguish it from the temperature of the actual Curie point.
Classical approaches to magnetic susceptibility and Bohr–van Leeuwen theorem
According to the Bohr–van Leeuwen theorem, when statistical mechanics and classical mechanics are applied consistently, the thermal average of the magnetization is always zero. Magn |
https://en.wikipedia.org/wiki/Arum%20maculatum | Arum maculatum is a woodland flowering plant species in the family Araceae. It is native across most of Europe, as well as Eastern Turkey and the Caucasus.
Description
The leaves of A. maculatum appear in the spring (April–May in the northern hemisphere, October–November in the southern hemisphere) and are 7 to 20 cm long. These are followed by the flowers borne on a poker-shaped inflorescence called a spadix, which is partially enclosed in a pale green spathe or leaf-like hood. The spathe can be up to 25 cm high and the fruiting spike which follows later in the season may be up to 5 cm. The flowers are hidden from sight, clustered at the base of the spadix with a ring of female flowers at the bottom and a ring of male flowers above them. The leaves may be either purple-spotted (var. maculatum) or unspotted (var. immaculatum).
Above the male flowers is a ring of hairs forming an insect trap. Insects, especially owl-midges Psychoda phalaenoides, are attracted to the spadix by its faecal odour and a temperature up to 15 °C warmer than the ambient temperature. The insects are trapped beneath the ring of hairs and are dusted with pollen by the male flowers before escaping and carrying the pollen to the spadices of other plants, where they pollinate the female flowers. The spadix may also be yellow, but purple is the more common.
In autumn, the lower ring of (female) flowers forms a cluster of bright red, berries up to 5 cm long which remain after the spathe and other leaves have withered away. These attractive red to orange berries are extremely poisonous.
The root-tuber may be very big and is used to store starch. In mature specimens, the tuber may be as much as 400 mm below ground level.
Many small rodents appear to find the spadix particularly attractive; finding examples of the plant with much of the spadix eaten away is common. The spadix produces heat and probably scent as the flowers mature, and this may attract the rodents.
Arum maculatum is also known as |
https://en.wikipedia.org/wiki/Heesch%27s%20problem | In geometry, the Heesch number of a shape is the maximum number of layers of copies of the same shape that can surround it with no overlaps and no gaps. Heesch's problem is the problem of determining the set of numbers that can be Heesch numbers. Both are named for geometer Heinrich Heesch, who found a tile with Heesch number 1 (the union of a square, equilateral triangle, and 30-60-90 right triangle) and proposed the more general problem.
For example, a square may be surrounded by infinitely many layers of congruent squares in the square tiling, while a circle cannot be surrounded by even a single layer of congruent circles without leaving some gaps. The Heesch number of the square is infinite and the Heesch number of the circle is zero. In more complicated examples, such as the one shown in the illustration, a polygonal tile can be surrounded by several layers, but not by infinitely many; the maximum number of layers is the tile's Heesch number.
Formal definitions
A tessellation of the plane is a partition of the plane into smaller regions called tiles. The zeroth corona of a tile is defined as the tile itself, and for k > 0 the kth corona is the set of tiles sharing a boundary point with the (k − 1)th corona. The Heesch number of a figure S is the maximum value k such that there exists a tiling of the plane, and tile t within that tiling, for which that all tiles in the zeroth through kth coronas of t are congruent to S. In some work on this problem this definition is modified to additionally require that the union of the zeroth through kth coronas of t is a simply connected region.
If there is no upper bound on the number of layers by which a tile may be surrounded, its Heesch number is said to be infinite. In this case, an argument based on Kőnig's lemma can be used to show that there exists a tessellation of the whole plane by congruent copies of the tile.
Example
Consider the non-convex polygon P shown in the figure to the right, which is formed from |
https://en.wikipedia.org/wiki/Brian%20Randell | Brian Randell DSc FBCS FLSW (born 1936) is a British computer scientist, and emeritus professor at the School of Computing, Newcastle University, United Kingdom. He specialises in research into software fault tolerance and dependability, and is a noted authority on the early pre-1950 history of computing hardware.
Biography
Randell was employed at English Electric from 1957 to 1964 where he was working on compilers. His work on ALGOL 60 is particularly well known, including the development of the Whetstone compiler for the English Electric KDF9, an early stack machine. In 1964, he joined IBM, where he worked at the Thomas J. Watson Research Center on high performance computer architectures and also on operating system design methodology. In May 1969, he became a professor of computing science at the then named University of Newcastle upon Tyne, where he has worked since then in the area of software fault tolerance and dependability.
He is a member of the Special Interest Group on Computers, Information and Society (SIGCIS) of the Society for the History of Technology CIS, and a founding member of the Editorial Board of the IEEE Annals of the History of Computing journal. He is a Fellow of the Association for Computing Machinery (2008). He was elected a Fellow of the Learned Society of Wales in 2011.
He was, until 1969, a member of the International Federation for Information Processing (IFIP) IFIP Working Group 2.1 (WG2.1) on Algorithmic Languages and Calculi, which specified, maintains, and supports the programming languages ALGOL 60 and ALGOL 68. He is also a founding member of IFIP WG2.3 on Programming Methodology, and of IFIP WG10.4 on Dependability and Fault Tolerance.
He is married (to Liz, a teacher of French) and has four children.
Work
Brian Randell's main research interests are in the field of computer science, specifically on system dependability and fault tolerance. His interest in the history of computing was started by coming across the then almos |
https://en.wikipedia.org/wiki/Contorsion%20tensor | The contorsion tensor in differential geometry is the difference between a connection with and without torsion in it. It commonly appears in the study of spin connections. Thus, for example, a vielbein together with a spin connection, when subject to the condition of vanishing torsion, gives a description of Einstein gravity. For supersymmetry, the same constraint, of vanishing torsion, gives (the field equations of) 11-dimensional supergravity. That is, the contorsion tensor, along with the connection, becomes one of the dynamical objects of the theory, demoting the metric to a secondary, derived role.
The elimination of torsion in a connection is referred to as the absorption of torsion, and is one of the steps of Cartan's equivalence method for establishing the equivalence of geometric structures.
Definition in metric geometry
In metric geometry, the contorsion tensor expresses the difference between a metric-compatible affine connection with Christoffel symbol and the unique torsion-free Levi-Civita connection for the same metric.
The contorsion tensor is defined in terms of the torsion tensor as (up to a sign, see below)
where the indices are being raised and lowered with respect to the metric:
.
The reason for the non-obvious sum in the definition of the contorsion tensor is due to the sum-sum difference that enforces metric compatibility. The contorsion tensor is antisymmetric in the first two indices, whilst the torsion tensor itself is antisymmetric in its last two indices; this is shown below.
The full metric compatible affine connection can be written as:
Where the torsion-free Levi-Civita connection:
Definition in affine geometry
In affine geometry, one does not have a metric nor a metric connection, and so one is not free to raise and lower indices on demand. One can still achieve a similar effect by making use of the solder form, allowing the bundle to be related to what is happening on its base space. This is an explicitly geometric v |
https://en.wikipedia.org/wiki/Ferran%20Adri%C3%A0 | Fernando Adrià Acosta (; born 14 May 1962) is a Spanish chef. He was the head chef of the El Bulli restaurant in Roses on the Costa Brava and is considered one of the best chefs in the world. He has often collaborated with his brother, the renowned pastry chef Albert Adrià.
Career
Ferran Adrià began his culinary career in 1980 during his stint as a dishwasher at the Hotel Playafels, in the town of Castelldefels. The chef de cuisine at this hotel taught him traditional Spanish cuisine. At 19 he was drafted into military service where he worked as a cook. In 1984, at the age of 22, Adrià joined the kitchen staff of elBulli as a line cook. Eighteen months later he became the head chef.
In 1994, Ferran Adrià and Juli Soler (his partner) sold 20% of their business to Miquel Horta (a Spanish millionaire and philanthropist and son of the founder of Nenuco) for 120 million pesetas. This event became a turning point for elBulli, the money was used to finance an expansion of the kitchen and the relationship with Horta opened the door to new clients, businessmen, and politicians who helped spread the word about the creative experimentation happening at the time in Cala Montjoi.
Along with British chef Heston Blumenthal, Adrià is often associated with "molecular gastronomy", although like Blumenthal the Spanish chef does not consider his cuisine to be of this category. Instead, he has referred to his cooking as deconstructivist. He defines the term as 'Taking a dish that is well known and transforming all its ingredients, or part of them; then modifying the dish's texture, form and/or its temperature. Deconstructed, such a dish will preserve its essence... but its appearance will be radically different from the original's.' His stated goal is to "provide unexpected contrasts of flavour, temperature and texture. Nothing is what it seems. The idea is to provoke, surprise and delight the diner."
elBulli was only open for about six months of the year, from mid-June to mid-Dece |
https://en.wikipedia.org/wiki/Shekel%20function | The Shekel function is a multidimensional, multimodal, continuous, deterministic function commonly used as a test function for testing optimization techniques.
The mathematical form of a function in dimensions with maxima is:
or, similarly,
Global minima
Numerically certified global minima and the corresponding solutions were obtained using interval methods for up to . |
https://en.wikipedia.org/wiki/Proband | In medical genetics and other medical fields, a proband, proposito (male proband), or proposita (female proband) is a particular subject (human or other animal) being studied or reported on. On pedigrees, the proband is noted with a square (male) or circle (female) shaded accordingly. Denoting the proband is important, so the relationship to other individuals can be seen and patterns established.
In most cases, the proband is the first affected family member who seeks medical attention for a genetic disorder. Among the ancestors of the proband, other subjects may manifest the disease, but the proband typically refers to the member seeking medical attention or being studied, even if affected ancestors are known. Often, affected ancestors are unknown due to the lack of information regarding those individuals or about the disease at the time they lived. Other ancestors might be undiagnosed due to the incomplete penetrance or variable expressivity.
The diagnosis of a proband raises the index of suspicion for the proband's relatives and some of them may be diagnosed with the same disease. Conventionally, when drawing a pedigree chart, instead of the first diagnosed person, the proband may be chosen from among the affected ancestors (parents, grandparents) from the first generation where the disease is found.
The term "proband" is also used in genealogy, where it denotes the root node of an ahnentafel, also referred to as the progenitor. |
https://en.wikipedia.org/wiki/Voltage%20regulator%20module | A voltage regulator module (VRM), sometimes called processor power module (PPM), is a buck converter that provides microprocessor and chipset the appropriate supply voltage, converting , or to lower voltages required by the devices, allowing devices with different supply voltages be mounted on the same motherboard. On personal computer (PC) systems, the VRM is typically made up of power MOSFET devices.
Overview
Most voltage regulator module implementations are soldered onto the motherboard. Some processors, such as Intel Haswell and Ice Lake CPUs, feature some voltage regulation components on the same CPU package, reduce the VRM design of the motherboard; such a design brings certain levels of simplification to complex voltage regulation involving numerous CPU supply voltages and dynamic powering up and down of various areas of a CPU. A voltage regulator integrated on-package or on-die is usually referred to as fully integrated voltage regulator (FIVR) or simply an integrated voltage regulator (IVR).
Most modern CPUs require less than , as CPU designers tend to use lower CPU core voltages; lower voltages help in reducing CPU power dissipation, which is often specified through thermal design power (TDP) that serves as the nominal value for designing CPU cooling systems.
Some voltage regulators provide a fixed supply voltage to the processor, but most of them sense the required supply voltage from the processor, essentially acting as a continuously-variable adjustable regulator. In particular, VRMs that are soldered to the motherboard are supposed to do the sensing, according to the Intel specification.
Modern video cards also use a VRM due to higher power and current requirements. These VRMs may generate a significant amount of heat and require heat sinks separate from the GPU.
Voltage identification
The correct supply voltage is communicated by the microprocessor to the VRM at startup via a number of bits called VID (voltage identification definition). In |
https://en.wikipedia.org/wiki/Vertical%20market%20software | Vertical market software is aimed at addressing the needs of any given business within a discernible vertical market (specific industry or market). While horizontal market software can be useful to a wide array of industries (such as word processors or spreadsheet programs), vertical market software is developed for and customized to a specific industry's needs.
Vertical market software is readily identifiable by the application specific graphical user interface which defines it. One example of vertical market software is point-of-sale software.
See also
Horizontal market software
Horizontal market
Product software implementation method
Enterprise resource planning
Customer relationship management
Content management system
Supply chain management
Resources
Microsoft ships first Windows OS for vertical market from InfoWorld
The Limits of Open Source - Vertical Markets Present Special Obstacles
Software by type |
https://en.wikipedia.org/wiki/Aresti%20Catalog | The Aresti Catalog is the Fédération Aéronautique Internationale (FAI) standards document enumerating the aerobatic manoeuvers permitted in aerobatic competition. Designed by Spanish aviator Colonel José Luis Aresti Aguirre (1919–2003), each figure in the catalog is represented by lines, arrows, geometric shapes and numbers representing the precise form of a manoeuver to be flown.
The catalog broadly classifies manoeuvers into numbered families. Families 1 through 8 depict basic figures, such as turns, loops and vertical lines; family 9 depicts rotational elements that can be added to basic figures to increase difficulty, change the direction of flight or invert the g-loading of the aircraft.
Notation
In Aresti notation, solid lines represent upright or positive-g manoeuvers and dashed lines represent inverted or negative-g manoeuvers; these are sometimes depicted in red. Thick dot represents the beginning of the manoeuver, while a short perpendicular line represents the end. Stalled wing manoeuvers such as spins and snap (flick) rolls are represented by triangles. Arrows represent rolling manoeuvers with numbers representing the extent and number of segments of the roll.
The catalog assigns each manoeuver a unique identifier, called a catalog number, and difficulty factor, represented by the symbol K. When a basic figure is combined with one or more rolling elements, the resultant figure K is the sum of all component Ks. During an aerobatics competition, judges grade the execution of each manoeuver with a value between 10 (perfect) and 0 (highly flawed). Each figure's grades are multiplied by its K and summed to yield a total raw score for the flight.
Notational systems for aerobatic manoeuvers have been used since the 1920s.
The first system accepted worldwide was published by French aviator François d'Huc Dressler in 1955 and 1956. It was used for international competitions through 1962.
José Aresti's development of a notation for aerobatic figures began |
https://en.wikipedia.org/wiki/Frank%20Ellison | Frank Cararas Ellison (March 14, 1887 – September 30, 1964) was an American model railroader who created the famous O scale Delta Lines model railroad in New Orleans, Louisiana and authored numerous articles from the 1930s to the 1950s.
Mr. Ellison died after a brief illness, at midnight, at Our Lady of The Lake hospital in Baton Rouge.
Born in New Orleans, Ellison lived in that city for most of his life until his final years when he lived in Baton Rouge, Louisiana with a son. A biographical sketch in the July 1976 edition of Model Railroader magazine states:
Frank C. Ellison was over the years, a railroad telegrapher, vaudeville marimbaist, stage designer, storyteller, model railroader, model railroad author, and above all, a gentleman.
As "The Three Ellisons", Mr. Ellison, his late wife and his brother had a leading billing on the Orpheum circuit around the country for many years. The team was billed with such acts as Charlie Chaplin and Buster Keaton, and participated, by her invitation, Sarah Bernhart's program in her final appearance. Their classical music act was played on xylophone, built by Ellison and his father.
Between 1934 and 1956 Ellison became the face of model railroading in the United States when he wrote hundreds of articles on all aspects of the hobby, many involving his O scale layout that he built at his large house in the Lakeview district of New Orleans that he named the Delta Lines.
Although most of his writing was for hobby magazines, Ellison had also written articles for The Times-Picayune newspaper and its afternoon counterpart the States-Item. From the late 1940s to the early 1950s Ellison wrote a series of articles for Model Railroader magazine entitled "The Art of Model Railroading." These missives were later collected into a book entitled Frank Ellison on Model Railroading (Fawcett Books, Greenwich CT, 1954). Ellison had worked for many years in theatre and this experience influenced his ideas about model railroad design in whic |
https://en.wikipedia.org/wiki/Orienting%20response | The orienting response (OR), also called orienting reflex, is an organism's immediate response to a change in its environment, when that change is not sudden enough to elicit the startle reflex. The phenomenon was first described by Russian physiologist Ivan Sechenov in his 1863 book Reflexes of the Brain, and the term ('ориентировочный рефлекс' in Russian) was coined by Ivan Pavlov, who also referred to it as the Shto takoye? (Что такое? or What is it?) reflex. The orienting response is a reaction to novel or significant stimuli. In the 1950s the orienting response was studied systematically by the Russian scientist Evgeny Sokolov, who documented the phenomenon called "habituation", referring to a gradual "familiarity effect" and reduction of the orienting response with repeated stimulus presentations.
Researchers have found a number of physiological mechanisms associated with OR, including changes in phasic and tonic skin conductance response (SCR), electroencephalogram (EEG), and heart rate following a novel or significant stimulus. These observations all occur within seconds of stimulus introduction. In particular, EEG studies of OR have corresponded particularly with the P300 wave and P3a component of the OR-related event-related potential (ERP).
Neural correlates
Current understanding of the localization of OR in the brain is still unclear. In one study using fMRI and SCR, researchers found novel visual stimuli associated with SCR responses typical of an OR also corresponded to activation in the hippocampus, anterior cingulate gyrus, and ventromedial prefrontal cortex. These regions are also believed to be largely responsible for emotion, decision making, and memory. Increases in cerebellar and extrastriate cortex were also recorded, which are significantly implicated in visual perception and processing.
Function
When an individual encounters a novel environmental stimulus, such as a bright flash of light or a sudden loud noise, they will pay attentio |
https://en.wikipedia.org/wiki/Castlequest | Castlequest (known in Japan as ) is an adventure/puzzle video game. It was developed and published by ASCII Corporation in 1985 for the FM-7, PC-88, and Sharp X1. Additional versions followed in 1986 for the Famicom and MSX, and was subsequently released in 1989 for the NES in the United States by Nexoft Corporation (the American division of ASCII).
It is the sequel to The Castle, released in 1985 for the MSX, SG-1000, and other systems (though not the NES). Like that game, it is an early example of the Metroidvania genre.
Gameplay
The object of the game is to navigate through Groken Castle to rescue Princess Margarita. The player can push certain objects throughout the game to accomplish progress. In some rooms, the prince can only advance to the next room by aligning cement blocks, Honey Jars, Candle Cakes, and Elevator Controlling Block. In some rooms, this can be quite time-consuming since the prince can only open a particular door if he can stand by the door, meaning that he can not open the door while jumping in mid-air. The prince must also carry a key that matches the color of the door he intends to be open. The player can navigate the castle with the help of a map that can be obtained from the first room that he/she begins. The map will provide the player with a matrix of 10x10 rooms and will highlight the room in which the princess is located. The player must also avoid touching enemies like Knights, Bishops, Wizards, Fire Spirits, Attack Cats and Phantom Flowers.
Release
In the Family Computer and NES versions, each room is wider than the screen, so the display scrolls horizontally as the player moves. Because of the different room sizes, many adjustments to the room layouts were made in comparison to the MSX version. In the Family Computer version, the player starts with 4 lives, and the game supports the Famicom Data Recorder and ASCII Turbo File peripherals for saving and loading game progress. When the game was reworked for the US NES release, the |
https://en.wikipedia.org/wiki/Berlin%20Circle | The Berlin Circle () was a group that maintained logical empiricist views about philosophy.
History
Berlin Circle was created in the late 1920s by Hans Reichenbach, Kurt Grelling and Walter Dubislav and composed of philosophers and scientists such as Carl Gustav Hempel, David Hilbert and Richard von Mises. Its original name was Die Gesellschaft für empirische Philosophie, which in English may be translated as "the society for empirical philosophy". Together with the Vienna Circle, they published the journal Erkenntnis ("Knowledge") edited by Rudolf Carnap and Reichenbach, and organized several congresses and colloquia concerning the philosophy of science, the first of which was held in Prague in 1929.
The Berlin Circle had much in common with the Vienna Circle, but the philosophies of the circles differed on a few subjects, such as probability and conventionalism. Reichenbach insisted on calling his philosophy logical empiricism, to distinguish it from the logical positivism of the Vienna Circle. Few people today make the distinction, and the words are often used interchangeably.
Members of the Berlin Circle were particularly active in analyzing the philosophical and logical consequences of the advances in contemporary physics, especially the theory of relativity. Apart from that, they denied the soundness of metaphysics and traditional philosophy and asserted that many philosophical problems are indeed meaningless.
After the rise of Nazism, several of the group's members emigrated to other countries, including Reichenbach, who moved to Turkey in 1933 and later to the United States in 1938; Dubislav emigrated to Prague in 1936; Hempel moved to Belgium in 1934 and later to the United States in 1939; and Grelling was killed in a concentration camp. A younger member of the Berlin Circle or Berlin School to leave Germany was Olaf Helmer who joined the RAND Corporation and played an important role in the development of the Delphi method used for predicting future tr |
https://en.wikipedia.org/wiki/Kurt%20Grelling | Kurt Grelling (2 March 1886 – September 1942) was a German logician and philosopher, member of the Berlin Circle.
Life and work
Kurt Grelling was born on 2 March 1886 in Berlin. His father, the Doctor of Jurisprudence Richard Grelling, and his mother, Margarethe (née Simon), were Jewish. Shortly after his arrival in 1905 at University of Göttingen, Grelling began a collaboration with philosopher Leonard Nelson, with whom he tried to solve Russell's paradox, which had shaken the foundations of mathematics when it was announced in 1903. Their 1908 paper included new paradoxes, including a semantic paradox that was named the Grelling–Nelson paradox.
He received his doctorate in mathematics from the same university in 1910 with a PhD dissertation on the development of arithmetic in axiomatic set theory, advised by David Hilbert. In a recorded interview with Herbert Enderton, Alfred Tarski mentions a meeting he had with Grelling in 1938, and says that Grelling was the author of the earliest textbook in set theory, probably but wrongly referring to this dissertation, since William Henry Young and Grace Chisholm Young's Set Theory was published in 1906.
As a skilled linguist, Grelling translated philosophical works from French, Italian and English to German, including four of Bertrand Russell's works. He became a strong proponent of Russell's writings thereafter.
From 1911 to 1922 Grelling published exclusively journalistic articles in publications connected with the Social Democratic Party of Germany.
In 1915 his father, Richard Grelling, wrote the anti-war book J'Accuse, condemning the actions of the Central Powers. It enjoyed huge sales outside Germany. Richard followed this success up with Das Verbrechen (The Crime), in which he attacked his critics, who included Kurt Grelling.
From 1924 onwards Grelling's publications were exclusively in the field of positivist philosophy.
Unable to find a university position in either Göttingen or Berlin, Grelling had to te |
https://en.wikipedia.org/wiki/Stag%20hunt | In game theory, the stag hunt, sometimes referred to as the assurance game, trust dilemma or common interest game, describes a conflict between safety and social cooperation. The stag hunt problem originated with philosopher Jean-Jacques Rousseau in his Discourse on Inequality. In the most common account of this dilemma, which is quite different from Rousseau's, two hunters must decide separately, and without the other knowing, whether to hunt a stag or a hare. However, both hunters know the only way to successfully hunt a stag is with the other's help. One hunter can catch a hare alone with less effort and less time, but it is worth far less than a stag and has much less meat. It would be much better for each hunter, acting individually, to give up total autonomy and minimal risk, which brings only the small reward of the hare. Instead, each hunter should separately choose the more ambitious and far more rewarding goal of getting the stag, thereby giving up some autonomy in exchange for the other hunter's cooperation and added might. This situation is often seen as a useful analogy for many kinds of social cooperation, such as international agreements on climate change.
The stag hunt differs from the prisoner's dilemma in that there are two pure-strategy Nash equilibria: one where both players cooperate, and one where both players defect. In the Prisoner's Dilemma, in contrast, despite the fact that both players cooperating is Pareto efficient, the only pure Nash equilibrium is when both players choose to defect.
An example of the payoff matrix for the stag hunt is pictured in Figure 2.
Formal definition
Formally, a stag hunt is a game with two pure strategy Nash equilibria—one that is risk dominant and another that is payoff dominant. The payoff matrix in Figure 1 illustrates a generic stag hunt, where . Often, games with a similar structure but without a risk dominant Nash equilibrium are called assurance games. For instance if a=10, b=5, c=0, and d=2. While ( |
https://en.wikipedia.org/wiki/Digital%20Audio%20Access%20Protocol | The Digital Audio Access Protocol (DAAP) is the proprietary protocol introduced by Apple in its iTunes software to share media across a local network.
DAAP addresses the same problems for Apple as the UPnP AV standards address for members of the Digital Living Network Alliance (DLNA).
Description
The DAAP protocol was originally introduced in iTunes version 4.0. Initially, Apple did not officially release a protocol description, but it has been reverse-engineered to a sufficient degree that reimplementations of the protocol for non-iTunes platforms have been possible.
A DAAP server is a specialized HTTP server, which performs two functions. It sends a list of songs and it streams requested songs to clients. There are also provisions to notify the client of changes to the server. Requests are sent to the server by the client in form of URLs and are responded to with data in mime-type, which can be converted to XML by the client. iTunes uses the zeroconf (also known as Bonjour) service to announce and discover DAAP shares on a local subnet. The DAAP service uses TCP port 3689 by default.
DAAP is one of two media sharing schemes that Apple has currently released. The other, Digital Photo Access Protocol (DPAP), is used by iPhoto for sharing images. They both rely on an underlying protocol, Digital Media Access Protocol (DMAP).
Early versions of iTunes allowed users to connect to shares across the Internet, however, in recent versions only computers on the same subnet can share music (workarounds such as port tunneling are possible). The Register speculates that Apple made this move in response to pressure from the record labels. More recent versions of iTunes also limit the number of clients to 5 unique IP addresses within a 24-hour period.
DAAP has also been implemented in other non-iTunes media applications such as Banshee, Amarok, Exaile (with a plugin), Songbird (with a plugin), Rhythmbox, and WiFiTunes.
DAAP authentication
Beginning with iTunes 4.2, Appl |
https://en.wikipedia.org/wiki/Universal%20instantiation | In predicate logic, universal instantiation (UI; also called universal specification or universal elimination, and sometimes confused with dictum de omni) is a valid rule of inference from a truth about each member of a class of individuals to the truth about a particular individual of that class. It is generally given as a quantification rule for the universal quantifier but it can also be encoded in an axiom schema. It is one of the basic principles used in quantification theory.
Example: "All dogs are mammals. Fido is a dog. Therefore Fido is a mammal."
Formally, the rule as an axiom schema is given as
for every formula A and every term a, where is the result of substituting a for each free occurrence of x in A. is an instance of
And as a rule of inference it is
from infer
Irving Copi noted that universal instantiation "...follows from variants of rules for 'natural deduction', which were devised independently by Gerhard Gentzen and Stanisław Jaśkowski in 1934."
Quine
According to Willard Van Orman Quine, universal instantiation and existential generalization are two aspects of a single principle, for instead of saying that "∀x x = x" implies "Socrates = Socrates", we could as well say that the denial "Socrates ≠ Socrates" implies "∃x x ≠ x". The principle embodied in these two operations is the link between quantifications and the singular statements that are related to them as instances. Yet it is a principle only by courtesy. It holds only in the case where a term names and, furthermore, occurs referentially.
See also
Existential instantiation
Existential generalization
Existential quantification
Inference rules |
https://en.wikipedia.org/wiki/Aufbau%20principle | The Aufbau principle (, from the German Aufbauprinzip, which means "building-up principle"), also called the Aufbau rule, states that in the ground state of an atom or ion, electrons fill subshells of the lowest available energy, then they fill subshells of higher energy. For example, the 1s subshell is filled before the 2s subshell is occupied. In this way, the electrons of an atom or ion form the most stable electron configuration possible. An example is the configuration for the phosphorus atom, meaning that the 1s subshell has 2 electrons, and so on.
The configuration is often abbreviated by writing only the valence electrons explicitly, while the core electrons are replaced by the symbol for the last previous noble gas in the periodic table, placed in square brackets. For phosphorus, the last previous noble gas is neon, so the configuration is abbreviated to [Ne] 3s2 3p3, where [Ne] signifies the core electrons whose configuration in phosphorus is identical to that of neon.
Electron behavior is elaborated by other principles of atomic physics, such as Hund's rule and the Pauli exclusion principle. Hund's rule asserts that if multiple orbitals of the same energy are available, electrons will occupy different orbitals singly and with the same spin before any are occupied doubly. If double occupation does occur, the Pauli exclusion principle requires that electrons that occupy the same orbital must have different spins (+ and −).
Passing from one element to another of the next higher atomic number, one proton and one electron are added each time to the neutral atom.
The maximum number of electrons in any shell is 2n2, where n is the principal quantum number.
The maximum number of electrons in a subshell is equal to 2(2 + 1), where the azimuthal quantum number is equal to 0, 1, 2, and 3 for s, p, d, and f subshells, so that the maximum numbers of electrons are 2, 6, 10, and 14 respectively. In the ground state, the electronic configuration can be built up by p |
https://en.wikipedia.org/wiki/The%20Legend%20of%20Kage | is a side-scrolling hack-and-slash game developed and published by Taito in 1985. In this game, the player controls the ninja Kage, with the objective being to get through five stages in order to save the pincess Kirihime. These stages are littered with enemies, however Kage has various skills and weapons on his hands in order to get through them.
The arcade release was considered a success for Taito, and exceeded sales expectations at the time of its release. It has been ported to a variety of home systems, has had sequels and spinoffs, and has been featured on various Taito compilations.
Gameplay
The player takes the role of a young Iga ninja named Kage ("Shadow"), on a mission to rescue Princess Kiri (hime) - the Shogun's daughter - from the villainous warlord Yoshi (ro Kuyigusa) and fellow evil samurai Yuki (nosuke Riko). The player is armed with a kodachi shortsword and an unlimited number of shuriken. Kage must fight his way through a forest, along a secret passageway, up a fortress wall, and through a castle, rescuing her twice (three times in the FC/NES version) in order to win the game. Each time the princess is rescued, the seasons change from summer to fall to winter and back to summer.
In home versions, grabbing a crystal ball causes the player's clothes to change to the next level in color and thereby attain certain powers (bigger shuriken or faster speed). If Kage is hit in a home version while in green or orange clothes, he does not die but reverts to his normal red clothes.
Cycles repeat after five levels are completed, and play continues until all lives are gone, which ends the game.
Development and release
The Legend of Kage was released by Taito in Japan in 1985, with a European release later in the year, and an American release in January 1986.
According to Hisayoshi Ogura, the game's composer, development came after a fast-paced period of game development within Taito, where it eased up around this game. Ogura specifically gave the ga |
https://en.wikipedia.org/wiki/Multiple%20drug%20resistance | Multiple drug resistance (MDR), multidrug resistance or multiresistance is antimicrobial resistance shown by a species of microorganism to at least one antimicrobial drug in three or more antimicrobial categories. Antimicrobial categories are classifications of antimicrobial agents based on their mode of action and specific to target organisms. The MDR types most threatening to public health are MDR bacteria that resist multiple antibiotics; other types include MDR viruses, parasites (resistant to multiple antifungal, antiviral, and antiparasitic drugs of a wide chemical variety).
Recognizing different degrees of MDR in bacteria, the terms extensively drug-resistant (XDR) and pandrug-resistant (PDR) have been introduced. Extensively drug-resistant (XDR) is the non-susceptibility of one bacteria species to all antimicrobial agents except in two or less antimicrobial categories. Within XDR, pandrug-resistant (PDR) is the non-susceptibility of bacteria to all antimicrobial agents in all antimicrobial categories. The definitions were published in 2011 in the journal Clinical Microbiology and Infection and are openly accessible.
Common multidrug-resistant organisms (MDROs)
Common multidrug-resistant organisms are usually bacteria:
Vancomycin-Resistant Enterococci (VRE)
Methicillin-resistant Staphylococcus aureus (MRSA)
Extended-spectrum β-lactamase (ESBLs) producing Gram-negative bacteria
Klebsiella pneumoniae carbapenemase (KPC) producing Gram-negatives
Multidrug-resistant Gram negative rods (MDR GNR) MDRGN bacteria such as Enterobacter species, E.coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa
Multi-drug-resistant tuberculosis
Overlapping with MDRGN, a group of Gram-positive and Gram-negative bacteria of particular recent importance have been dubbed as the ESKAPE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species).
Bacterial resistance |
https://en.wikipedia.org/wiki/Journal%20of%20Genetics | The Journal of Genetics is a peer-reviewed scientific journal in the field of genetics and evolution. It was established in 1910 by the British geneticists William Bateson and Reginald Punnett and is one of the oldest genetics journals. It was later edited by J.B.S. Haldane, who emigrated to India in 1957, and continued publishing the journal from there.
On Haldane's death in 1964, his second wife Helen Spurway continued to publish the journal with Madhav Gadgil, H. Sharat Chandra, and Suresh Jayakar as editors until Spurway died in 1977 and the journal ceased publication. With the permission of Naomi Mitchison, Haldane's sister, it was revived in 1985 and has been published by the Indian Academy of Sciences, currently in collaboration with Springer Science+Business Media, since then. All volumes published between 1910 and 1994 (vol. 1-73) are available free on the website of the Indian Academy of Sciences.
According to the Journal Citation Reports, the journal has a 2019 impact factor of 0.993.
It adopted the "Continuous Article Publication" (CAP) mode from January 2019. |
https://en.wikipedia.org/wiki/Sulfur%20monoxide | Sulfur monoxide is an inorganic compound with formula . It is only found as a dilute gas phase. When concentrated or condensed, it converts to S2O2 (disulfur dioxide). It has been detected in space but is rarely encountered intact otherwise.
Structure and bonding
The SO molecule has a triplet ground state similar to O2 and S2, that is, each molecule has two unpaired electrons. The S−O bond length of 148.1 pm is similar to that found in lower sulfur oxides (e.g. S8O, S−O = 148 pm) but is longer than the S−O bond in gaseous S2O (146 pm), SO2 (143.1 pm) and SO3 (142 pm).
The molecule is excited with near infrared radiation to the singlet state (with no unpaired electrons). The singlet state is believed to be more reactive than the ground triplet state, in the same way that singlet oxygen is more reactive than triplet oxygen.
Production and reactions
Production of SO as a reagent in organic syntheses has centred on using compounds that "extrude" SO. Examples include the decomposition of the relatively simple molecule ethylene episulfoxide: as well as more complex examples, such as a trisulfide oxide, C10H6S3O.
C2H4SO → C2H4 + SO
The SO molecule is thermodynamically unstable, converting initially to S2O2.
SO inserts into alkenes, alkynes and dienes producing thiiranes, molecules with three-membered rings containing sulfur.
Generation under extreme conditions
In the laboratory, sulfur monoxide can be produced by treating sulfur dioxide with sulfur vapor in a glow discharge. It has been detected in single-bubble sonoluminescence of concentrated sulfuric acid containing some dissolved noble gas.
Benner and Stedman developed a chemiluminescence detector for sulfur via the reaction between sulfur monoxide and ozone:
SO + O3 → SO2* + O2
SO2* → SO2 + hν
Occurrence
Ligand for transition metals
As a ligand SO can bond in a number different ways:
a terminal ligand, with a bent M−O−S arrangement, for example with titanium oxyfluoride
a terminal ligand, with a bent M−S |
https://en.wikipedia.org/wiki/SUnit | SUnit is a unit testing framework for the programming language Smalltalk. It is the original source of the xUnit design, originally written by one of the creators of Extreme Programming, Kent Beck. SUnit allows writing tests and checking results in Smalltalk.
History
SUnit was originally described by Beck in "Simple Smalltalk Testing: With Patterns" (1989), then published as chapter 30 "Simple Smalltalk Testing", in the book Kent Beck's Guide to Better Smalltalk by Kent Beck, Donald G. Firesmith (Editor) (Publisher: Cambridge University Press, Pub. Date: December 1998, , 408pp)
External links
@ Camp Smalltalk
SUnit @ Ward Cunningham's Wiki
Extreme programming
Unit testing frameworks
Unit testing |
https://en.wikipedia.org/wiki/Crest%20and%20trough | A crest point on a wave is the maximum value of upward displacement within a cycle. A crest is a point on a surface wave where the displacement of the medium is at a maximum. A trough is the opposite of a crest, so the minimum or lowest point in a cycle.
When the crests and troughs of two sine waves of equal amplitude and frequency intersect or collide, while being in phase with each other, the result is called constructive interference and the magnitudes double (above and below the line). When in antiphase – 180° out of phase – the result is destructive interference: the resulting wave is the undisturbed line having zero amplitude.
See also
Crest factor
Superposition principle
Wave |
https://en.wikipedia.org/wiki/Wireless%20network%20interface%20controller | A wireless network interface controller (WNIC) is a network interface controller which connects to a wireless network, such as Wi-Fi or Bluetooth, rather than a wired network, such as a Token Ring or Ethernet. A WNIC, just like other NICs, works on the layers 1 and 2 of the OSI model and uses an antenna to communicate via radio waves.
A wireless network interface controller may be implemented as an expansion card and connected using PCI bus or PCIe bus, or connected via USB, PC Card, ExpressCard, Mini PCIe or M.2.
The low cost and ubiquity of the Wi-Fi standard means that many newer mobile computers have a wireless network interface built into the motherboard.
The term is usually applied to IEEE 802.11 adapters; it may also apply to a NIC using protocols other than 802.11, such as one implementing Bluetooth connections.
Modes of operation
An 802.11 WNIC can operate in two modes known as infrastructure mode and ad hoc mode:
Infrastructure mode
In an infrastructure mode network the WNIC needs a wireless access point: all data is transferred using the access point as the central hub. All wireless nodes in an infrastructure mode network connect to an access point. All nodes connecting to the access point must have the same service set identifier (SSID) as the access point, and if a kind of wireless security is enabled on the access point (such as WEP or WPA), they must share the same keys or other authentication parameters.
Ad hoc mode
In an ad hoc mode network the WNIC does not require an access point, but rather can interface with all other wireless nodes directly. All the nodes in an ad hoc network must have the same channel and SSID.
Specifications
The IEEE 802.11 standard sets out low-level specifications for how all 802.11 wireless networks operate. Earlier 802.11 interface controllers are usually only compatible with earlier variants of the standard, while newer cards support both current and old standards.
Specifications commonly used in marketi |
https://en.wikipedia.org/wiki/De%20Bruijn%20sequence | In combinatorial mathematics, a de Bruijn sequence of order n on a size-k alphabet A is a cyclic sequence in which every possible length-n string on A occurs exactly once as a substring (i.e., as a contiguous subsequence). Such a sequence is denoted by and has length , which is also the number of distinct strings of length n on A. Each of these distinct strings, when taken as a substring of , must start at a different position, because substrings starting at the same position are not distinct. Therefore, must have at least symbols. And since has exactly symbols, de Bruijn sequences are optimally short with respect to the property of containing every string of length n at least once.
The number of distinct de Bruijn sequences is
The sequences are named after the Dutch mathematician Nicolaas Govert de Bruijn, who wrote about them in 1946. As he later wrote, the existence of de Bruijn sequences for each order together with the above properties were first proved, for the case of alphabets with two elements, by . The generalization to larger alphabets is due to . Automata for recognizing these sequences are denoted as de Bruijn automata.
In most applications, A = {0,1}.
History
The earliest known example of a de Bruijn sequence comes from Sanskrit prosody where, since the work of Pingala, each possible three-syllable pattern of long and short syllables is given a name, such as 'y' for short–long–long and 'm' for long–long–long. To remember these names, the mnemonic yamātārājabhānasalagām is used, in which each three-syllable pattern occurs starting at its name: 'yamātā' has a short–long–long pattern, 'mātārā' has a long–long–long pattern, and so on, until 'salagām' which has a short–short–long pattern. This mnemonic, equivalent to a de Bruijn sequence on binary 3-tuples, is of unknown antiquity, but is at least as old as Charles Philip Brown's 1869 book on Sanskrit prosody that mentions it and considers it "an ancient line, written by Pāṇini".
In 1894, A. de |
https://en.wikipedia.org/wiki/Sunshine%20Project | The Sunshine Project was an international NGO dedicated to upholding prohibitions against biological warfare and, particularly, to preventing military abuse of biotechnology. It was directed by Edward Hammond.
With offices in Austin, Texas, and Hamburg, Germany, the Sunshine Project worked by exposing research on biological and chemical weapons. Typically, it accessed documents under the Freedom of Information Act and other open records laws, publishing reports and encouraging action to reduce the risk of biological warfare. It tracked the construction of high containment laboratory facilities and the dual-use activities of the U.S. biodefense program. Another focus was on documenting government-sponsored research and development of incapacitating "non-lethal" weapons, such as the chemical used by Russia to end the Moscow theater hostage crisis in 2002. The Sunshine Project was also active in meetings of the Biological Weapons Convention, the main international treaty prohibiting biological warfare.
An announcement was posted on The Sunshine Project website, "As of 1 February 2008, the Sunshine Project is suspending its operations", due to a lack of funding. Its website remained online for some time after this date and could be used as an archive of its activities and publications from 2000 through 2008. However, as of October 2013 the Sunshine Project website was offline.
Biological weapons safety
The Sunshine Project
Biosafety Bites (v.2) #14 6 June 2006
External links
The Sun Sets on the Sunshine Project
Biological warfare |
https://en.wikipedia.org/wiki/Larder | A larder is a cool area for storing food prior to use. Originally, it was where raw meat was larded—covered in fat—to be preserved. By the 18th century, the term had expanded: at that point, a dry larder was where bread, pastry, milk, butter, or cooked meats were stored. Larders were commonplace in houses before the widespread use of the refrigerator.
Stone larders were designed to keep cold in the hottest weather. They had slate or marble shelves two or three inches thick. These shelves were wedged into thick stone walls. Fish or vegetables were laid directly onto the shelves and covered with muslin or handfuls of wet rushes were sprinkled under and around.
Essential qualities
Cool, dry, and well-ventilated.
Usually on the shady side of the house.
No fireplaces or hot flues in any of the adjoining walls.
Might have a door to an outside yard.
Had windows with wire gauze in them instead of glass.
Description
In the northern hemisphere, most houses would be arranged to have their larders and kitchens on the north or west side of the house where they received the least amount of sun. In Australia and New Zealand, larders were placed on the south or east sides of the house for the same reason.
Many larders have small, unglazed windows with window openings covered in fine mesh. This allows free circulation of air without allowing flies to enter. Many larders also have tiled or painted walls to simplify cleaning. Older larders, and especially those in larger houses, have hooks in the ceiling to hang joints of meat.
A pantry may contain a thrawl, a term used in Derbyshire and Yorkshire to denote a stone slab or shelf used to keep food cool in the days before refrigeration was domestically available. In a late medieval hall, a thrawl would have been equivalent to a larder. In a large or moderately large 19th-century house, all these rooms would have been placed in the lowest, and/or as convenient, coolest possible location in the building to use the mass of the groun |
https://en.wikipedia.org/wiki/Ground%20resonance | Ground resonance is an imbalance in the rotation of a helicopter rotor when the blades become bunched up on one side of their rotational plane and cause an oscillation in phase with the frequency of the rocking of the helicopter on its landing gear. The effect is similar to the behavior of a washing machine when the clothes are concentrated in one place during the spin cycle. It occurs when the landing gear is prevented from freely moving about on the horizontal plane, typically when the aircraft is on the ground.
Causes and consequences
Articulated rotor systems with drag hinges allow each individual blade to advance or lag in its rotation to compensate for stress on the blade caused by the acceleration and deceleration of the rotor hub (due to momentum conservation). When the spacing of the blades becomes irregular, it shifts the rotor's center of mass from the axis of rotation, which causes an oscillation. When the airframe begins to rock back and forth from the oscillation, the oscillations can reinforce each other and cause the rotor's center of gravity to spiral away from the axis of rotation to a point beyond the compensating ability of the damping system.
Ground resonance is usually precipitated by a hard landing or an asymmetrical ground contact, and is more likely to occur when components of the landing gear or damping system are improperly maintained, such as the drag hinge dampers, oleo struts, or wheel tire pressure. Under extreme conditions, the initial shock can cause violent oscillations that quickly build and result in catastrophic damage of the entire airframe. In some cases, complete destruction occurs, e.g. body panels, fuel tanks, and engines are torn away, even at normal rotor speed.
Mitigation
Proper maintenance of the helicopter's damping system components can prevent ground resonance from taking hold. When it does occur, recovery is often possible if action is taken quickly. If sufficient rotor RPM exists, immediate takeoff can restore r |
https://en.wikipedia.org/wiki/GABAA%20receptor | {{DISPLAYTITLE:GABAA receptor}}
The GABAA receptor (GABAAR) is an ionotropic receptor and ligand-gated ion channel. Its endogenous ligand is γ-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system. Accurate regulation of GABAergic transmission through appropriate developmental processes, specificity to neural cell types, and responsiveness to activity is crucial for the proper functioning of nearly all aspects of the central nervous system (CNS). Upon opening, the GABAA receptor on the postsynaptic cell is selectively permeable to chloride ions (Cl−) and, to a lesser extent, bicarbonate ions (HCO3−).
GABAAR are members of the ligand-gated ion channel receptor superfamily, which is a chloride channel family with a dozen or more heterotetrametric subtypes and 19 distinct subunits. These subtypes have distinct brain regional and subcellular localization, age-dependent expression, and the ability to undergo plastic alterations in response to experience, including drug exposure.
GABAAR is not just the target of agonist depressants and antagonist convulsants, but most GABAAR medicines also act at additional (allosteric) binding sites on GABAAR proteins. Some sedatives and anxiolytics, such as benzodiazepines and related medicines, act on GABAAR subtype-dependent extracellular domain sites. Alcohols and neurosteroids, among other general anesthetics, act at GABAAR subunit-interface transmembrane locations. High anesthetic dosages of ethanol act on GABAAR subtype-dependent transmembrane domain locations. Ethanol acts at GABAAR subtype-dependent extracellular domain locations at low intoxication concentrations. Thus, GABAAR subtypes have pharmacologically distinct receptor binding sites for a diverse range of therapeutically significant neuropharmacological drugs.
Depending on the membrane potential and the ionic concentration difference, this can result in ionic fluxes across the pore. If the membrane potential is higher than the |
https://en.wikipedia.org/wiki/Francesco%20Severi | Francesco Severi (13 April 1879 – 8 December 1961) was an Italian mathematician. He was the chair of the committee on Fields Medal on 1936, at the first delivery.
Severi was born in Arezzo, Italy. He is famous for his contributions to algebraic geometry and the theory of functions of several complex variables. He became the effective leader of the Italian school of algebraic geometry. Together with Federigo Enriques, he won the Bordin prize from the French Academy of Sciences.
He contributed in a major way to birational geometry, the theory of algebraic surfaces, in particular of the curves lying on them, the theory of moduli spaces and the theory of functions of several complex variables. He wrote prolifically, and some of his work (following the intuition-led approach of Federigo Enriques) has subsequently been shown to be not rigorous according to the then new standards set in particular by Oscar Zariski and Andre Weil. Although many of his arguments have since been made rigorous, a significant fraction were not only lacking in rigor but also wrong (in contrast to the work of Enriques, which though not rigorous was almost entirely correct). At the personal level, according to he was easily offended, and he was involved in a number of controversies. Most notably, he was a staunch supporter of the Italian fascist regime of Benito Mussolini and was included on a committee of academics that was to conduct an anti-semitic purge of all scholarly societies and academic institutions.
Biography
His childhood was marked by the death of his father, which occurred when he was 9 years old. This had serious economic repercussions on their family. Although he had to earn a living while conducting private lessons, Francesco Severi managed to continue his studies and enroll in the engineering course at the University of Turin. Due to the influence of courses by Corrado Segre, Severi quickly found a passion for pure mathematics.
In 1900, he completed his training with a thes |
https://en.wikipedia.org/wiki/Estimation%20theory | Estimation theory is a branch of statistics that deals with estimating the values of parameters based on measured empirical data that has a random component. The parameters describe an underlying physical setting in such a way that their value affects the distribution of the measured data. An estimator attempts to approximate the unknown parameters using the measurements.
In estimation theory, two approaches are generally considered:
The probabilistic approach (described in this article) assumes that the measured data is random with probability distribution dependent on the parameters of interest
The set-membership approach assumes that the measured data vector belongs to a set which depends on the parameter vector.
Examples
For example, it is desired to estimate the proportion of a population of voters who will vote for a particular candidate. That proportion is the parameter sought; the estimate is based on a small random sample of voters. Alternatively, it is desired to estimate the probability of a voter voting for a particular candidate, based on some demographic features, such as age.
Or, for example, in radar the aim is to find the range of objects (airplanes, boats, etc.) by analyzing the two-way transit timing of received echoes of transmitted pulses. Since the reflected pulses are unavoidably embedded in electrical noise, their measured values are randomly distributed, so that the transit time must be estimated.
As another example, in electrical communication theory, the measurements which contain information regarding the parameters of interest are often associated with a noisy signal.
Basics
For a given model, several statistical "ingredients" are needed so the estimator can be implemented. The first is a statistical sample – a set of data points taken from a random vector (RV) of size N. Put into a vector,
Secondly, there are M parameters
whose values are to be estimated. Third, the continuous probability density function (pdf) or its |
https://en.wikipedia.org/wiki/Dihydroxyacetone%20phosphate | Dihydroxyacetone phosphate (DHAP, also glycerone phosphate in older texts) is the anion with the formula HOCH2C(O)CH2OPO32-. This anion is involved in many metabolic pathways, including the Calvin cycle in plants and glycolysis. It is the phosphate ester of dihydroxyacetone.
Role in glycolysis
Dihydroxyacetone phosphate lies in the glycolysis metabolic pathway, and is one of the two products of breakdown of fructose 1,6-bisphosphate, along with glyceraldehyde 3-phosphate. It is rapidly and reversibly isomerised to glyceraldehyde 3-phosphate.
The numbering of the carbon atoms indicates the fate of the carbons according to their position in fructose 6-phosphate.
Role in other pathways
In the Calvin cycle, DHAP is one of the products of the sixfold reduction of 1,3-bisphosphoglycerate by NADPH. It is also used in the synthesis of sedoheptulose 1,7-bisphosphate and fructose 1,6-bisphosphate, both of which are used to reform ribulose 5-phosphate, the 'key' carbohydrate of the Calvin cycle.
DHAP is also the product of the dehydrogenation of L-glycerol-3-phosphate, which is part of the entry of glycerol (sourced from triglycerides) into the glycolytic pathway. Conversely, reduction of glycolysis-derived DHAP to L-glycerol-3-phosphate provides adipose cells with the activated glycerol backbone they require to synthesize new triglycerides. Both reactions are catalyzed by the enzyme glycerol 3-phosphate dehydrogenase with NAD+/NADH as cofactor.
DHAP also has a role in the ether-lipid biosynthesis process in the protozoan parasite Leishmania mexicana.
DHAP is a precursor to 2-oxopropanal. This conversion is the basis of a potential biotechnological route to the commodity chemical 1,2-propanediol.
See also
Dihydroxyacetone
Glycerol 3-phosphate shuttle |
https://en.wikipedia.org/wiki/Approach%20space | In topology, a branch of mathematics, approach spaces are a generalization of metric spaces, based on point-to-set distances, instead of point-to-point distances. They were introduced by Robert Lowen in 1989, in a series of papers on approach theory between 1988 and 1995.
Definition
Given a metric space (X, d), or more generally, an extended pseudoquasimetric (which will be abbreviated ∞pq-metric here), one can define an induced map d: X × P(X) → [0,∞] by d(x, A) = inf{d(x, a) : a ∈ A}. With this example in mind, a distance on X is defined to be a map X × P(X) → [0,∞] satisfying for all x in X and A, B ⊆ X,
d(x, {x}) = 0,
d(x, Ø) = ∞,
d(x, A∪B) = min(d(x, A), d(x, B)),
For all 0 ≤ ε ≤ ∞, d(x, A) ≤ d(x, A(ε)) + ε,
where we define A(ε) = {x : d(x, A) ≤ ε}.
(The "empty infimum is positive infinity" convention is like the nullary intersection is everything convention.)
An approach space is defined to be a pair (X, d) where d is a distance function on X. Every approach space has a topology, given by treating A → A(0) as a Kuratowski closure operator.
The appropriate maps between approach spaces are the contractions. A map f: (X, d) → (Y, e) is a contraction if e(f(x), f[A]) ≤ d(x, A) for all x ∈ X and A ⊆ X.
Examples
Every ∞pq-metric space (X, d) can be distanced to (X, d), as described at the beginning of the definition.
Given a set X, the discrete distance is given by d(x, A) = 0 if x ∈ A and d(x, A) = ∞ if x ∉ A. The induced topology is the discrete topology.
Given a set X, the indiscrete distance is given by d(x, A) = 0 if A is non-empty, and d(x, A) = ∞ if A is empty. The induced topology is the indiscrete topology.
Given a topological space X, a topological distance is given by d(x, A) = 0 if x ∈ A, and d(x, A) = ∞ otherwise. The induced topology is the original topology. In fact, the only two-valued distances are the topological distances.
Let P = [0, ∞] be the extended non-negative reals. Let d+(x, A) = max(x − sup A, 0) for x ∈ P and A ⊆ P. Given any |
https://en.wikipedia.org/wiki/GTPase-activating%20protein | GTPase-activating proteins or GTPase-accelerating proteins (GAPs) are a family of regulatory proteins whose members can bind to activated G proteins and stimulate their GTPase activity, with the result of terminating the signaling event. GAPs are also known as RGS protein, or RGS proteins, and these proteins are crucial in controlling the activity of G proteins. Regulation of G proteins is important because these proteins are involved in a variety of important cellular processes. The large G proteins, for example, are involved in transduction of signaling from the G protein-coupled receptor for a variety of signaling processes like hormonal signaling, and small G proteins are involved in processes like cellular trafficking and cell cycling. GAP's role in this function is to turn the G protein's activity off. In this sense, GAPs function is opposite to that of guanine nucleotide exchange factors (GEFs), which serve to enhance G protein signaling.
Mechanism
GAP are heavily linked to the G-protein linked receptor family. The activity of G proteins comes from their ability to bind guanosine triphosphate (GTP). Binding of GTP inherently changes the activity of the G proteins and increases their activity, through the loss of inhibitory subunits. In this more active state, G proteins can bind other proteins and turn on downstream signalling targets. This whole process is regulated by GAPs, which can down regulate the activity of G proteins.
G proteins can weakly hydrolyse GTP, breaking a phosphate bond to make GDP. In the GDP-bound state, the G proteins are subsequently inactivated and can no longer bind their targets. This hydrolysis reaction, however, occurs very slowly, meaning G proteins have a built-in timer for their activity. G proteins have a window of activity followed by slow hydrolysis, which turns them off. GAP accelerates this G protein timer by increasing the hydrolytic GTPase activity of the G proteins, hence the name GTPase-activating protein. |
https://en.wikipedia.org/wiki/Tar | Tar is a dark brown or black viscous liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat.
Mineral products resembling tar can be produced from fossil hydrocarbons, such as petroleum. Coal tar is produced from coal as a byproduct of coke production.
Terminology
"Tar" and "pitch" can be used interchangeably; asphalt (naturally occurring pitch) may also be called either "mineral tar" or "mineral pitch". There is a tendency to use "tar" for more liquid substances and "pitch" for more solid (viscoelastic) substances. Both "tar" and "pitch" are applied to viscous forms of asphalt, such as the asphalt found in naturally occurring tar pits (e.g., the La Brea Tar Pits in Los Angeles). "Rangoon tar", also known as "Burmese oil" or "Burmese naphtha", is also a form of petroleum. Oil sands, found extensively in Alberta, Canada and composed of asphalt, are colloquially referred to as "tar sands".
Wood tar
For at least 600 years, wood tar has been used as a water repellent coating for boats, ships, and roofs. In Scandinavia, it was produced as a cash crop. "Peasant Tar" might be named for the district of its production.
Wood tar is still used as an additive in the flavoring of candy, alcohol, and other foods. Wood tar is microbicidal. Producing tar from wood was known in ancient Greece and has probably been used in Scandinavia since the Iron Age. Production and trade in pine-derived tar was a major contributor in the economies of Northern Europe and Colonial America. Its main use was in preserving wooden sailing vessels against rot. For centuries, dating back at least to the 14th century, tar was among Sweden's most important exports. Sweden exported 13,000 barrels of tar in 1615 and 227,000 barrels in the peak year of 1863. The largest user was the Royal Navy of the United Kingdom. Demand for tar declined with the advent of iron and steel ships. |
https://en.wikipedia.org/wiki/NOV%20%28computers%29 | NOV, or News Overview, is a widely deployed indexing method for Usenet articles, also found in some Internet email implementations. Written in 1992 by Geoff Collyer, NOV replaced a variety of incompatible indexing schemes used in different client programs, each typically requiring custom modifications to each news server before they could be used. In modern NNTP implementations, NOV is exposed as the and related commands.
Operation
In its original implementation, the header lines of each incoming message are examined, and a single line of text is appended to the overview files, with one overview file present for each newsgroup. Tab (ASCII code 9) characters and line breaks within the headers are converted to spaces (ASCII code 32), and the header fields within each overview line are then delimited by tab characters.
The first seven fields in a NOV line are fixed and unlabeled:
Subject: header contents
From: header contents
Date: header contents
Message-ID: header contents
References: header contents
Size of the article in octets
Lines: header contents
The header lines are those defined in either RFC 2822 or RFC 1036. If data for any of these fields is missing, a tab alone is put in its place. The value of the size field is approximate, as servers may count line endings as one or two characters. Additionally, the lines value may be calculated by the server, supplied by the message sender, or omitted altogether.
An arbitrary number of additional fields may be added to any NOV line. The eighth and later fields must be labeled in the form "Header-Name: contents", again delimited by tabs. The order and presence of additional fields are allowed to vary from line to line, and from server to server. Some server provide a schema of what is recorded to new overview lines in the form of an NNTP command, but this cannot be relied upon to be accurate for older entries.
In practice, most servers supply only one optional field, the contents of the Xref: header, to allow |
https://en.wikipedia.org/wiki/The%20Saint%20%281997%20film%29 | The Saint is a 1997 American thriller film directed by Phillip Noyce, written by Jonathan Hensleigh and Wesley Strick, and starring Val Kilmer in the title role, with Elisabeth Shue and Rade Šerbedžija. The plot of the film revolves around the title character who is a high tech thief and master of disguise, who becomes the anti-hero while using the moniker of various saints. He paradoxically lives in the underworld of international industrial theft and espionage. The film was a modest financial success with a worldwide box office of $169.4 million, rentals of $28.2 million, and continuous DVD sales.
It is loosely based on the character of Simon Templar created by Leslie Charteris in 1928 for a series of books published as "The Saint", which ran until 1983. The Saint character has also featured in a series of Hollywood films made between 1938 and 1954, a 1940s radio series starring Vincent Price (and others) as Templar, a popular British television series of the 1960s starring Roger Moore, and a 1970s series starring Ian Ogilvy.
Plot
At the Saint Ignatius Orphanage, a rebellious boy named John Rossi refers to himself as "Simon Templar" and leads fellow orphans in an attempt to run away. He tries to bid farewell to a girl named Agnes with a kiss, but they are caught and she accidentally falls from a balcony to her death.
As an adult, Simon — now a professional thief dubbed "The Saint" for using Catholic saints as aliases — steals a microchip from a Russian oil company. Simon stages the burglary during a political rally for the company's owner Ivan Tretiak, a billionaire oligarch and former Communist Party boss rallying support against Russian President Karpov. Simon is caught by Tretiak's son Ilya but escapes with the microchip, and is hired by Tretiak to steal a revolutionary cold fusion formula discovered by Emma Russell, an American electrochemist working at Oxford; Tretiak plans to use Emma's formula for clean, inexpensive energy to monopolize the energy market |
https://en.wikipedia.org/wiki/Elementary%20arithmetic | Elementary arithmetic is a branch of mathematics involving basic numerical operations, namely addition, subtraction, multiplication, and division. Due to its low level of abstraction, broad range of application, and position as the foundation of all mathematics, elementary arithmetic is generally the first critical branch of mathematics to be taught in schools.
Digits
Symbols called digits are used to represent the value of numbers in a numeral system. The most commonly used digits are the Arabic numerals (0 to 9). The Hindu-Arabic numeral system is the most commonly used numeral system, being a positional notation system used to represent numbers using these digits.
Successor function and size
In elementary arithmetic, the successor of a natural number (including zero) is the result of adding one to that number, whereas the predecessor of a natural number (excluding zero) is the result obtained by subtracting one from that number. For example, the successor of zero is one and the predecessor of eleven is ten ( and ). Every natural number has a successor, and all natural numbers (except zero) have a predecessor.
If one number is greater than () another number, then the latter is less than () the first one. For example, three is less than eight (), and eight is greater than three ().
Counting
Counting involves assigning a natural number to each object in a set, starting with one for the first object and increasing by one for each subsequent object. The number of objects in the set is the count which is equal to the highest natural number assigned to an object in the set. This count is also known as the cardinality of the set.
Counting can also be the process of tallying using tally marks, drawing a mark for each object in a set.
In more advanced mathematics, the process of counting can be thought of as constructing a one-to-one correspondence (or bijection), between the elements of a set and the set , where is a natural number, and the size of the set is .
|
https://en.wikipedia.org/wiki/Sigma-ideal | In mathematics, particularly measure theory, a -ideal, or sigma ideal, of a σ-algebra (, read "sigma") is a subset with certain desirable closure properties. It is a special type of ideal. Its most frequent application is in probability theory.
Let be a measurable space (meaning is a -algebra of subsets of ). A subset of is a -ideal if the following properties are satisfied:
;
When and then implies ;
If then
Briefly, a sigma-ideal must contain the empty set and contain subsets and countable unions of its elements. The concept of -ideal is dual to that of a countably complete (-) filter.
If a measure is given on the set of -negligible sets ( such that ) is a -ideal.
The notion can be generalized to preorders with a bottom element as follows: is a -ideal of just when
(i')
(ii') implies and
(iii') given a sequence there exists some such that for each
Thus contains the bottom element, is downward closed, and satisfies a countable analogue of the property of being upwards directed.
A -ideal of a set is a -ideal of the power set of That is, when no -algebra is specified, then one simply takes the full power set of the underlying set. For example, the meager subsets of a topological space are those in the -ideal generated by the collection of closed subsets with empty interior.
See also |
https://en.wikipedia.org/wiki/Triparental%20mating | Triparental mating is a form of bacterial conjugation where a conjugative plasmid present in one bacterial strain assists the transfer of a mobilizable plasmid present in a second bacterial strain into a third bacterial strain. Plasmids are introduced into bacteria for such purposes as transformation, cloning, or transposon mutagenesis. Triparental matings can help overcome some of the barriers to efficient plasmid mobilization. For instance, if the conjugative plasmid and the mobilizable plasmid are members of the same incompatibility group they do not need to stably coexist in the second bacterial strain for the mobilizable plasmid to be transferred.
History
Triparental mating was identified in yeasts in 1960 and then in Escherichia coli in 1962.
Process
Requirements
A helper strain, carrying a conjugative plasmid (such as the F-plasmid) that codes for genes required for conjugation and DNA transfer.
A donor strain, carrying a mobilizable plasmid that can utilize the transfer functions of the conjugative plasmid.
A recipient strain, you wish to introduce the mobilizable plasmid into.
Five to seven days are required to determine if the
plasmid was successfully introduced into the new bacterial
strain and confirm that there is no carryover of the helper or
donor strain.
In contrast, electroporation does not require a helper or
donor strain. This helps
avoid possible contamination with other strains. The introduction
of the plasmid can be verified in the recipient
strain in two days, making electroporation a faster and
more efficient method of transformation. Electroporation however does not work with all bacteria and is mostly limited to well-characterized model organisms.
See also
Bacterial conjugation
Plasmid
Transposon (applications)
Bacteriophage
Three-parent baby
External links
Protocol for P. aeruginosa |
https://en.wikipedia.org/wiki/Eponychium | In human anatomy, the eponychium is the thickened layer of skin at the base of the fingernails and toenails. It can also be called the medial or proximal nail fold. The eponychium differs from the cuticle; the eponychium comprises live skin cells whilst the cuticle is dead skin cells. Its function is to protect the area between the nail and epidermis from exposure to bacteria. The vascularization pattern is similar to that of perionychium.
In hoofed animals, the eponychium is the deciduous hoof capsule in fetuses and newborn foals, and is a part of the permanent hoof in older animals.
The word eponychium comes .
See also
Hyponychium
Lunula |
https://en.wikipedia.org/wiki/PBKDF2 | In cryptography, PBKDF1 and PBKDF2 (Password-Based Key Derivation Function 1 and 2) are key derivation functions with a sliding computational cost, used to reduce vulnerability to brute-force attacks.
PBKDF2 is part of RSA Laboratories' Public-Key Cryptography Standards (PKCS) series, specifically PKCS#5 v2.0, also published as Internet Engineering Task Force's RFC2898. It supersedes PBKDF1, which could only produce derived keys up to 160 bits long. RFC8018 (PKCS#5 v2.1), published in 2017, recommends PBKDF2 for password hashing.
Purpose and operation
PBKDF2 applies a pseudorandom function, such as hash-based message authentication code (HMAC), to the input password or passphrase along with a salt value and repeats the process many times to produce a derived key, which can then be used as a cryptographic key in subsequent operations. The added computational work makes password cracking much more difficult, and is known as key stretching.
When the standard was written in the year 2000 the recommended minimum number of iterations was 1,000, but the parameter is intended to be increased over time as CPU speeds increase. A Kerberos standard in 2005 recommended 4,096 iterations; Apple reportedly used 2,000 for iOS 3, and 10,000 for iOS 4; while LastPass in 2011 used 5,000 iterations for JavaScript clients and 100,000 iterations for server-side hashing. In 2023, OWASP recommended to use 600,000 iterations for PBKDF2-HMAC-SHA256 and 210,000 for PBKDF2-HMAC-SHA512.
Having a salt added to the password reduces the ability to use precomputed hashes (rainbow tables) for attacks, and means that multiple passwords have to be tested individually, not all at once. The public key cryptography standard recommends a salt length of at least 64 bits. The US National Institute of Standards and Technology recommends a salt length of 128 bits.
Key derivation process
The PBKDF2 key derivation function has five input parameters:
where:
is a pseudorandom function of two parameters |
https://en.wikipedia.org/wiki/Half-integer | In mathematics, a half-integer is a number of the form
where is a whole number. For example,
are all half-integers. The name "half-integer" is perhaps misleading, as the set may be misunderstood to include numbers such as 1 (being half the integer 2). A name such as "integer-plus-half" may be more accurate, but even though not literally true, "half integer" is the conventional term. Half-integers occur frequently enough in mathematics and in quantum mechanics that a distinct term is convenient.
Note that halving an integer does not always produce a half-integer; this is only true for odd integers. For this reason, half-integers are also sometimes called half-odd-integers. Half-integers are a subset of the dyadic rationals (numbers produced by dividing an integer by a power of two).
Notation and algebraic structure
The set of all half-integers is often denoted
The integers and half-integers together form a group under the addition operation, which may be denoted
However, these numbers do not form a ring because the product of two half-integers is not a half-integer; e.g. The smallest ring containing them is , the ring of dyadic rationals.
Properties
The sum of half-integers is a half-integer if and only if is odd. This includes since the empty sum 0 is not half-integer.
The negative of a half-integer is a half-integer.
The cardinality of the set of half-integers is equal to that of the integers. This is due to the existence of a bijection from the integers to the half-integers: , where is an integer
Uses
Sphere packing
The densest lattice packing of unit spheres in four dimensions (called the D4 lattice) places a sphere at every point whose coordinates are either all integers or all half-integers. This packing is closely related to the Hurwitz integers: quaternions whose real coefficients are either all integers or all half-integers.
Physics
In physics, the Pauli exclusion principle results from definition of fermions as particles which have spins |
https://en.wikipedia.org/wiki/Veronese%20surface | In mathematics, the Veronese surface is an algebraic surface in five-dimensional projective space, and is realized by the Veronese embedding, the embedding of the projective plane given by the complete linear system of conics. It is named after Giuseppe Veronese (1854–1917). Its generalization to higher dimension is known as the Veronese variety.
The surface admits an embedding in the four-dimensional projective space defined by the projection from a general point in the five-dimensional space. Its general projection to three-dimensional projective space is called a Steiner surface.
Definition
The Veronese surface is the image of the mapping
given by
where denotes homogeneous coordinates. The map is known as the Veronese embedding.
Motivation
The Veronese surface arises naturally in the study of conics. A conic is a degree 2 plane curve, thus defined by an equation:
The pairing between coefficients and variables is linear in coefficients and quadratic in the variables; the Veronese map makes it linear in the coefficients and linear in the monomials. Thus for a fixed point the condition that a conic contains the point is a linear equation in the coefficients, which formalizes the statement that "passing through a point imposes a linear condition on conics".
Veronese map
The Veronese map or Veronese variety generalizes this idea to mappings of general degree d in n+1 variables. That is, the Veronese map of degree d is the map
with m given by the multiset coefficient, or more familiarly the binomial coefficient, as:
The map sends to all possible monomials of total degree d (of which there are ); we have since there are variables to choose from; and we subtract since the projective space has coordinates. The second equality shows that for fixed source dimension n, the target dimension is a polynomial in d of degree n and leading coefficient
For low degree, is the trivial constant map to and is the identity map on so d is generally taken to be |
https://en.wikipedia.org/wiki/High-end%20audio | High-end audio is a class of consumer home audio equipment marketed to audiophiles on the basis of high price or quality, and esoteric or novel sound reproduction technologies. The term can refer simply to the price, to the build quality of the components, or to the subjective or objective quality of sound reproduction.
Definition
The distinction between the terms high end and high fidelity is not well defined. According to one industry commentator, high-end could be defined as, "Gear below which's price and performance one could not go without compromising the music and the sound." Harry Pearson, founder of The Absolute Sound magazine, is widely acknowledged to have coined the term high-end audio.
Costs
High-end audio equipment can be extremely expensive. It is sometimes referred to as cost-no-object equipment. Audiophile equipment can encompass the full range from budget to high-end in terms of price.
Fidelity assessment
The fidelity of sound reproduction may be assessed aurally or using audio system measurements.
The human sense of hearing is subjective and difficult to define. Psychoacoustics is a division of acoustics that studies this field.
Measurements can be deceiving; high or low figures of certain technical characteristics do not necessarily offer a good representation of how the equipment sounds to each person. For example, some valve amplifiers produce greater amounts of total harmonic distortion, but this type of distortion (2nd harmonic) is not as disturbing to the ear as the higher-order distortions produced by poorly designed transistor equipment.
The validity of certain products is often questioned. These include accessories such as speaker wires utilizing exotic materials (such as oxygen-free copper) and construction geometries, cable stands for lifting them off the floor (as a way to control mechanically induced vibrations), connectors, sprays and other tweaks.
See also
Audio noise measurement
Broadcast quality
Professional audio
S |
https://en.wikipedia.org/wiki/Stochastic%20electrodynamics | Stochastic electrodynamics (SED) is a variant of classical electrodynamics (CED) of theoretical physics. SED consists of a set of controversial theories that posit the existence of a classical Lorentz invariant radiation field having statistical properties similar to that of the electromagnetic zero-point field (ZPF) of quantum electrodynamics (QED).
Classical background field
The background field is introduced as a Lorentz force in the (classical) Abraham–Lorentz–Dirac equation (see: Abraham–Lorentz–Dirac force), where the classical statistics of the electric and magnetic fields and quadratic combinations thereof are chosen to match the vacuum expectation values of the equivalent operators in QED. The field is generally represented as a discrete sum of Fourier components each with amplitude and phase that are independent classical random variables, distributed so that the statistics of the fields are isotropic and unchanged under boosts. This prescription is such that each Fourier mode at frequency (f) is expected to have an energy of hf/2, equaling that of the ground state of the vacuum modes of QED. Unless cut off, the total field has an infinite energy density, with a spectral energy density (per unit frequency per unit volume) [2h/c3]f3 where h is Planck's constant. Consequently, the background field is a classical version of the electromagnetic ZPF of QED, though in SED literature the field is commonly referred to simply as 'the ZPF' without making that distinction. Any finite cutoff frequency of the field itself would be incompatible with Lorentz invariance. For this reason, some researchers prefer to think of cutoff frequency in terms of the response of particles to the field rather than as a property of the field itself.
Brief history
Stochastic electrodynamics is a term for a collection of research efforts of many different styles based on the ansatz that there exists a Lorentz invariant random electromagnetic radiation. The basic ideas have been arou |
https://en.wikipedia.org/wiki/Johnny%20Stenb%C3%A4ck | Johnny Stenbäck is a Finnish software engineer mostly known for his work on the Mozilla browser. He was one of the first developers outside Netscape to get involved with the Mozilla source released by Netscape in March 1998. Stenbäck started working on the source code soon after the release, then working for the Finnish software company Citec (Citec created DocZilla, a Mozilla-based SGML browser). In 2000 he was hired by Netscape and moved to California. In 2003 Stenbäck joined the Mozilla Foundation.
Stenbäck is currently working at Google.
Publications
Co-author of "Extending Mozilla or How to Do the Impossible", which was originally prepared as a tutorial for Xtech'99.
Editor of Document Object Model (DOM) Level 2 HTML Specification, a W3C Recommendation.
Mozilla developers
Free software programmers
Open source people
Computer programmers
Living people
Finnish computer programmers
Year of birth missing (living people)
Finnish expatriates in the United States |
https://en.wikipedia.org/wiki/Thermal%20expansion | Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions.
Temperature is a monotonic function of the average molecular kinetic energy of a substance. When a substance is heated, molecules begin to vibrate and move more, usually creating more distance between themselves. Substances which contract with increasing temperature are unusual, and only occur within limited temperature ranges (see examples below). The relative expansion (also called strain) divided by the change in temperature is called the material's coefficient of linear thermal expansion and generally varies with temperature. As energy in particles increases, they start moving faster and faster, weakening the intermolecular forces between them and therefore expanding the substance.
Overview
Predicting expansion
If an equation of state is available, it can be used to predict the values of the thermal expansion at all the required temperatures and pressures, along with many other state functions.
Contraction effects (negative thermal expansion)
A number of materials contract on heating within certain temperature ranges; this is usually called negative thermal expansion, rather than "thermal contraction". For example, the coefficient of thermal expansion of water drops to zero as it is cooled to 3.983 °C and then becomes negative below this temperature; this means that water has a maximum density at this temperature, and this leads to bodies of water maintaining this temperature at their lower depths during extended periods of sub-zero weather.
Other materials are also known to exhibit negative thermal expansion. Fairly pure silicon has a negative coefficient of thermal expansion for temperatures between about 18 and 120 kelvin. ALLVAR Alloy 30, a titanium alloy, exhibits anisotropic negative thermal expansion across a wide range of temperatures.
Factors affecting thermal expansion
Unlike g |
https://en.wikipedia.org/wiki/Entry%20point | In computer programming, an entry point is the place in a program where the execution of a program begins, and where the program has access to command line arguments.
To start a program's execution, the loader or operating system passes control to its entry point. (During booting, the operating system itself is the program). This marks the transition from load time (and dynamic link time, if present) to run time.
For some operating systems and programming languages, the entry point is in a runtime library, a set of support functions for the language. The library code initializes the program and then passes control to the program proper. In other cases, the program may initialize the runtime library itself.
In simple systems, execution begins at the first statement, which is common in interpreted languages, simple executable formats, and boot loaders. In other cases, the entry point is at some other known memory address which can be an absolute address or relative address (offset).
Alternatively, execution of a program can begin at a named point, either with a conventional name defined by the programming language or operating system or at a caller-specified name. In many C-family languages, this is a function called main; as a result, the entry point is often known as the main function.
In JVM languages such as Java the entry point is a static method called main; in CLI languages such as C# the entry point is a static method named Main.
Usage
Entry points apply both to source code and to executable files. However, in day-to-day software development, programmers specify the entry points only in source code, which makes them much better known. Entry points in executable files depend on the application binary interface (ABI) of the actual operating system, and are generated by the compiler or linker (if not fixed by the ABI). Other linked object files may also have entry points, which are used later by the linker when generating entry points of an executable fil |
https://en.wikipedia.org/wiki/Loudspeaker%20acoustics | Loudspeaker acoustics is a subfield of acoustical engineering concerned with the reproduction of sound and the parameters involved in doing so in actual equipment.
Engineers measure the performance of drivers and complete speaker systems to characterize their behavior, often in an anechoic chamber, outdoors, or using time windowed measurement systems -- all to avoid including room effects (e.g., reverberation) in the measurements.
Designers use models (from electrical filter theory) to predict the performance of drive units in different enclosures, now almost always based on the work of A N Thiele and Richard Small.
Important driver characteristics are:
Frequency response
Off-axis response dispersion pattern, lobing
Sensitivity (dB SPL for 1 watt input)
Maximum power handling
Non-linear distortion
Colouration (i.e., more or less, delayed resonance).
It is the performance of a loudspeaker/listening room combination that really matters, as the two interact in multiple ways. There are two approaches to high-quality reproduction. One ensures the listening room is reasonably 'alive' with reverberant sound at all frequencies, in which case the speakers should ideally have equal dispersion at all frequencies in order to equally excite the reverberant fields created by reflections off room surfaces. The other attempts to arrange the listening room to be 'dead' acoustically, leaving indirect sound to the dispersion of the speakers need only be sufficient to cover the listening positions.
A dead or inert acoustic may be best, especially if properly filled with 'surround' reproduction, so that the reverberant field of the original space is reproduced realistically. This is currently quite hard to achieve, and so the ideal loudspeaker systems for stereo reproduction would have a uniform dispersion at all frequencies. Listening to sound in an anechoic "dead" room is quite different from listening in a conventional room, and, while revealing about loudspeaker behaviour it h |
https://en.wikipedia.org/wiki/Arcadia%20%28utopia%29 | Arcadia () refers to a vision of pastoralism and harmony with nature. The term is derived from the Greek province of the same name which dates to antiquity; the province's mountainous topography and sparse population of pastoralists later caused the word Arcadia to develop into a poetic byword for an idyllic vision of unspoiled wilderness. Arcadia is a poetic term associated with bountiful natural splendor and harmony. The 'Garden' is often inhabited by shepherds. The concept also figures in Renaissance mythology. Although commonly thought of as being in line with Utopian ideals, Arcadia differs from that tradition in that it is more often specifically regarded as unattainable. Furthermore, it is seen as a lost, Edenic form of life, contrasting to the progressive nature of Utopian desires.
The inhabitants were often regarded as having continued to live after the manner of the Golden Age, without the pride and avarice that corrupted other regions. It is also sometimes referred to in English poetry as Arcady. The inhabitants of this region bear an obvious connection to the figure of the noble savage, both being regarded as living close to nature, uncorrupted by civilization, and virtuous.
In antiquity
According to Greek mythology, Arcadia of Peloponnesus was the domain of Pan, a virgin wilderness home to the god of the forest and his court of dryads, nymphs and other spirits of nature. It was one version of paradise, though only in the sense of being the abode of supernatural entities, not an afterlife for deceased mortals.
In the 3rd century BCE the Greek poet Theocritus wrote idealised views of the lives of peasants in Arcadia for his fellow educated inhabitants of the squalid and disease-ridden city of Alexandria.
Greek mythology inspired the Roman poet Virgil to write his Eclogues, a series of poems set in Arcadia.
In the Renaissance
Arcadia has remained a popular artistic subject since antiquity, both in visual arts and literature. Images of beautiful ny |
https://en.wikipedia.org/wiki/Gross%20margin | Gross margin is the difference between revenue and cost of goods sold (COGS), divided by revenue. Gross margin is expressed as a percentage. Generally, it is calculated as the selling price of an item, less the cost of goods sold (e.g., production or acquisition costs, not including indirect fixed costs like office expenses, rent, or administrative costs), then divided by the same selling price. "Gross margin" is often used interchangeably with "gross profit", however, the terms are different: "gross profit" is technically an absolute monetary amount and "gross margin" is technically a percentage or ratio.
Gross margin is a kind of profit margin, specifically a form of profit divided by net revenue, e.g., gross (profit) margin, operating (profit) margin, net (profit) margin, etc.
Purpose
The purpose of margins is "to determine the value of incremental sales, and to guide pricing and promotion decision."
"Margin on sales represents a key factor behind many of the most fundamental business considerations, including budgets and forecasts. All managers should, and generally do, know their approximate business margins. Managers differ widely, however, in the assumptions they use in calculating margins and in the ways they analyze and communicate these important figures."
Percentage margins and unit margins
Gross margin can be expressed as a percentage or in total financial terms. If the latter, it can be reported on a per-unit basis or on a per-period basis for a business.
"Margin (on sales) is the difference between selling price and cost. This difference is typically expressed either as a percentage of selling price or on a per-unit basis. Managers need to know margins for almost all marketing decisions. Margins represent a key factor in pricing, return on marketing spending, earnings forecasts, and analyses of customer profitability." In a survey of nearly 200 senior marketing managers, 78 percent responded that they found the "margin %" metric very useful whi |
https://en.wikipedia.org/wiki/Mathematical%20chemistry | Mathematical chemistry is the area of research engaged in novel applications of mathematics to chemistry; it concerns itself principally with the mathematical modeling of chemical phenomena. Mathematical chemistry has also sometimes been called computer chemistry, but should not be confused with computational chemistry.
Major areas of research in mathematical chemistry include chemical graph theory, which deals with topology such as the mathematical study of isomerism and the development of topological descriptors or indices which find application in quantitative structure-property relationships; and chemical aspects of group theory, which finds applications in stereochemistry and quantum chemistry. Another important area is molecular knot theory and circuit topology that describe the topology of folded linear molecules such as proteins and Nucleic Acids.
The history of the approach may be traced back to the 19th century. Georg Helm published a treatise titled "The Principles of Mathematical Chemistry: The Energetics of Chemical Phenomena" in 1894. Some of the more contemporary periodical publications specializing in the field are MATCH Communications in Mathematical and in Computer Chemistry, first published in 1975, and the Journal of Mathematical Chemistry, first published in 1987. In 1986 a series of annual conferences MATH/CHEM/COMP taking place in Dubrovnik was initiated by the late Ante Graovac.
The basic models for mathematical chemistry are molecular graph and topological index.
In 2005 the International Academy of Mathematical Chemistry (IAMC) was founded in Dubrovnik (Croatia) by Milan Randić. The Academy has 82 members (2009) from all over the world, including six scientists awarded with a Nobel Prize.
See also
Bibliography
Molecular Descriptors for Chemoinformatics, by R. Todeschini and V. Consonni, Wiley-VCH, Weinheim, 2009.
Mathematical Chemistry Series, by D. Bonchev, D. H. Rouvray (Eds.), Gordon and Breach Science Publisher, Amsterdam, 2000 |
https://en.wikipedia.org/wiki/Phenotypic%20switching | Phenotypic switching is switching between multiple cellular morphologies. David R. Soll described two such systems: the first high frequency switching system between several morphological stages and a second high frequency switching system between opaque and white cells. The latter is an epigenetic switching system
Phenotypic switching in Candida albicans is often used to refer to the epigenetic white-to-opaque switching system. C. albicans needs this switch for sexual mating.
Next to the two above mentioned switching systems many other switching systems are known in C. albicans.
A second example occurs in melanoma, where malignantly transformed pigment cells switch back-and-forth between phenotypes of proliferation and invasion in response to changing microenvironments, driving metastatic progression.
See also
Polyphenism |
https://en.wikipedia.org/wiki/PXES | PXES also known as PXES Universal Linux Thin Client, was created in early 2001 by Diego Torres Milano. PXES is a Linux distribution designed to be run on thin clients using PXE; however, it is also possible to boot PXES from a CD-ROM or hard disk if the NIC or BIOS does not support PXE.
In 2006, The PXES project merged with 2X Software, who are merging PXES with the 2XOS. Distribution of PXES will remain free. |
https://en.wikipedia.org/wiki/National%20Defence%20Radio%20Establishment | The National Defence Radio Establishment (, FRA) is a Swedish
government agency organised under the Ministry of Defence. The two main tasks of FRA are signals intelligence (SIGINT), and support to government authorities and state-owned companies regarding computer security.
The FRA is not allowed to initialize any surveillance on their own, and operates purely on assignment from the Government, the Government Offices, the Armed Forces, the Swedish National Police Board and Swedish Security Service (SÄPO). Decisions and oversight regarding information interception is provided by the Defence Intelligence Court and the Defence Intelligence Commission; additional oversight regarding protection of privacy is provided by the Swedish Data Protection Authority.
History
Signals Intelligence has existed in Sweden since 1905 when Swedish General Staff and Naval Staff respectively, had departments for signals intelligence and cryptanalysis. These departments succeeded, for instance, to decode the Russian Baltic Sea Fleet cipher. After World War I, this ability mostly ceased as politicians did not see its value and did not grant funding. The Swedish Navy still continued in a smaller scale and developed the competence further. One of the first major successes was in 1933 when the cipher of the Russian OGPU (predecessor to KGB) was solved.
In 1937, the Swedish Defence Staff was established and the Crypto Department, with its Crypto Detail IV, was responsible for cryptanalysis. In 1940, when Germany occupied Denmark and Norway, the German Wehrmacht requested to use the Swedish telephone network for its communication. This was accepted and Crypto Detail IV immediately started to intercept. The traffic was almost always encrypted by the German state-of-the-art cipher machine Geheimfernschreiber. This device was believed to produce indecipherable messages, with its 893,622,318,929,520,960 different crypto key settings. After two weeks of single hand work, the Swedish professor o |
https://en.wikipedia.org/wiki/Tetractys | The tetractys (), or tetrad, or the tetractys of the decad is a triangular figure consisting of ten points arranged in four rows: one, two, three, and four points in each row, which is the geometrical representation of the fourth triangular number. As a mystical symbol, it was very important to the secret worship of Pythagoreanism. There were four seasons, and the number was also associated with planetary motions and music.
Pythagorean symbol
The first four numbers symbolize the musica universalis and the Cosmos as:
Monad – Unity
Dyad – Power – Limit/Unlimited (peras/apeiron)
Triad – Harmony
Tetrad – Kosmos
The four rows add up to ten, which was unity of a higher order (The Dekad).
The Tetractys symbolizes the four classical elements—air, fire, water, and earth.
The Tetractys represented the organization of space:
the first row represented zero dimensions (a point)
the second row represented one dimension (a line of two points)
the third row represented two dimensions (a plane defined by a triangle of three points)
the fourth row represented three dimensions (a tetrahedron defined by four points)
A prayer of the Pythagoreans shows the importance of the Tetractys (sometimes called the "Mystic Tetrad"), as the prayer was addressed to it.
As a portion of the secret religion, initiates were required to swear a secret oath by the Tetractys. They then served as novices, which required them to observe silence for a period of five years.
The Pythagorean oath also mentioned the Tetractys:
By that pure, holy, four lettered name on high,
nature's eternal fountain and supply,
the parent of all souls that living be,
by him, with faith find oath, I swear to thee.
It is said that the Pythagorean musical system was based on the Tetractys as the rows can be read as the ratios of 4:3 (perfect fourth), 3:2 (perfect fifth), 2:1 (octave), forming the basic intervals of the Pythagorean scales. That is, Pythagorean scales are generated from combining pure fourths (in a |
https://en.wikipedia.org/wiki/Epistemic%20possibility | In philosophy and modal logic, epistemic possibility relates a statement under consideration to the current state of our knowledge about the actual world: a statement is said to be:
epistemically possible if it may be true, for all we know
epistemically necessary if it is certain (or must be the case), given what we know
epistemically impossible if it cannot be true, given what we know
Epistemic possibility is often contrasted with subjunctive possibility (or alethic possibility), and although epistemic and subjunctive possibilities are often expressed using the same modal terms (such as possibly, could be, must be) or similar modal terms that are sometimes confused (such as may be and might be), statements that are qualified in terms of epistemic possibility and statements that are qualified in terms of subjunctive possibility have importantly different meanings.
The contrast is best explained by example. Consider the two statements:
Japan might have been victorious in World War II
Japan may have been victorious in World War II
Although these two statements are often confused with one another, they mean two different things: the first says something true about the vagaries of war; the second says something that is certainly false. The difference comes from the fact that the first statement—a statement of subjunctive possibility—says something about how things might have been under counterfactual conditions, whereas the second—a statement of epistemic possibility—says something about the relation between a particular outcome (a victory by Japan) and our knowledge about the actual world (since, as it happens, we know perfectly well that that particular outcome did not actually obtain, we know that what it says is false).
The parallel distinction arises between types of conditionals (if-then statements). Consider the difference between the epistemic connection expressed by an indicative conditional and the causal or metaphysical relation expressed by a su |
https://en.wikipedia.org/wiki/Isopropyl%20%CE%B2-D-1-thiogalactopyranoside | {{DISPLAYTITLE:Isopropyl β-D-1-thiogalactopyranoside}}
Isopropyl β--1-thiogalactopyranoside (IPTG) is a molecular biology reagent. This compound is a molecular mimic of allolactose, a lactose metabolite that triggers transcription of the lac operon, and it is therefore used to induce protein expression where the gene is under the control of the lac operator.
Mechanism of action
Like allolactose, IPTG binds to the lac repressor and releases the tetrameric repressor from the lac operator in an allosteric manner, thereby allowing the transcription of genes in the lac operon, such as the gene coding for beta-galactosidase, a hydrolase enzyme that catalyzes the hydrolysis of β-galactosides into monosaccharides. But unlike allolactose, the sulfur (S) atom creates a chemical bond which is non-hydrolyzable by the cell, preventing the cell from metabolizing or degrading the inducer. Therefore, its concentration remains constant during an experiment.
IPTG uptake by E. coli can be independent of the action of lactose permease, since other transport pathways are also involved. At low concentration, IPTG enters cells through lactose permease, but at high concentrations (typically used for protein induction), IPTG can enter the cells independently of lactose permease.
Use in laboratory
When stored as a powder at 4 °C or below, IPTG is stable for 5 years. It is significantly less stable in solution; Sigma recommends storage for no more than a month at room temperature. IPTG is an effective inducer of protein expression in the concentration range of 100 μmol/L to 3.0 mmol/L. Typically, a sterile, filtered 1 mol/L solution of IPTG is added 1:1000 to an exponentially growing bacterial culture, to give a final concentration of 1 mmol/L. The concentration used depends on the strength of induction required, as well as the genotype of cells or plasmid used. If lacIq, a mutant that over-produces the lac repressor, is present, then a higher concentration of IPTG may be necessary.
|
https://en.wikipedia.org/wiki/Burroughs%20Medium%20Systems | The Burroughs B2500 through Burroughs B4900 was a series of mainframe computers developed and manufactured by Burroughs Corporation in Pasadena, California, United States, from 1966 to 1991. They were aimed at the business world with an instruction set optimized for the COBOL programming language. They were also known as Burroughs Medium Systems, by contrast with the Burroughs Large Systems and Burroughs Small Systems.
History and architecture
First generation
The B2500 and B3500 computers were announced in 1966.
They operated directly on COBOL-68's primary decimal data types: strings of up to 100 digits, with one EBCDIC or ASCII digit character or two 4-bit binary-coded decimal BCD digits per byte. Portable COBOL programs did not use binary integers at all, so the B2500 did not either, not even for memory addresses. Memory was addressed down to the 4-bit digit in big-endian style, using 5-digit decimal addresses. Floating point numbers also used base 10 rather than some binary base, and had up to 100 mantissa digits. A typical COBOL statement 'ADD A, B GIVING C' may use operands of different lengths, different digit representations, and different sign representations. This statement compiled into a single 12-byte instruction with 3 memory operands.
Complex formatting for printing was accomplished by executing a single EDIT instruction with detailed format descriptors. Other high level instructions implemented "translate this buffer through this (e.g. EBCDIC to ASCII) conversion table into that buffer" and "sort this table using these sort requirements into that table". In extreme cases, single instructions could run for several hundredths of a second. MCP could terminate over-long instructions but could not interrupt and resume partially completed instructions. (Resumption is a prerequisite for doing page style virtual memory when operands cross page boundaries.)
The machine matched COBOL so closely that the COBOL compiler was simple and fast, and CO |
https://en.wikipedia.org/wiki/Rostam | Rostam or Rustam ( ) is a legendary hero in Persian mythology, the son of Zāl and Rudaba, whose life and work was immortalized by the 10th-century Persian poet Ferdowsi in the Shahnameh, or Epic of Kings, which contains pre-Islamic Iranian folklore and history. However, the roots of the narrative date much earlier.
In the Shahnameh, Rostam and his predecessors are Marzbans of Sistan (present-day Iran and Afghanistan). Rostam is best known for his tragic fight with Esfandiyār, the other legendary Iranian hero; for his expedition to Mazandaran (not to be confused with the modern Mazandaran Province); and for tragically fighting and killing his son, Sohrab, without knowing who his opponent is. He is also known for the story of his Seven Labours. Rostam is eventually killed by Shaghad, his half-brother.
Rostam was always represented as the mightiest of Iranian paladins (holy warriors), and the atmosphere of the episodes in which he features is strongly reminiscent of the Parthian Empire. He rides the legendary stallion Rakhsh and wears a special suit named Babr-e Bayan in battles.
Origins
While the narrative of the Shahname is the definitive work on Rostam, Ferdowsi did not invent the character; Rostam stories were popular as far back as the seventh century in Pars and originated much earlier, likely in Eastern Iranian-speaking territories. He famously wears the zīn-i palang or "panther-skin garment":
Background
In the Shahnameh, Rostam is a native of Zabulistan, a historical region roughly corresponding to today's Zabul Province, southern Afghanistan. His mother Rudaba was a princess of Kabul. Rostam is the champion of champions and is involved in numerous stories, constituting some of the most popular (and arguably some of most masterfully created) parts of the Shahnameh. In Shahnameh, Rostam—like his grandfather Sam—works as both a faithful military general as well as king-maker for the Kayanian dynasty of Persia.
As a young child, he slays the maddened white |
https://en.wikipedia.org/wiki/General-purpose%20markup%20language | A general-purpose markup language is a markup language that is used for more than one purpose or situation. Other, more specialized domain-specific markup languages are often based upon these languages. For example, HTML 4.1 and earlier are domain-specific markup languages (for webpages), and are based on the syntax of SGML, which is a general-purpose markup language.
List
Notable general-purpose markup languages include:
ASN.1 (Abstract Syntax Notation One)
EBML
LML – general-purpose markup language for expressing markdown, variables, and expressions for machine-readable and executable legal documentation
GML – the predecessor of SGML
SGML – a predecessor of XML
XML – a stripped-down form of SGML
YAML
GLML – General-purpose Legal Markup Language
See also
Comparison of document markup languages
General-purpose language
General-purpose modeling language
General-purpose programming language
S-expression
Data serialization formats |
https://en.wikipedia.org/wiki/List%20of%20web%20service%20protocols | The following is a list of web service protocols.
BEEP - Blocks Extensible Exchange Protocol
CTS - Canonical Text Services Protocol
E-Business XML
Hessian
Internet Open Trading Protocol
JSON-RPC
JSON-WSP
SOAP - outgrowth of XML-RPC, originally an acronym for Simple Object Access Protocol
Universal Description, Discovery, and Integration (UDDI)
Web Processing Service (WPS)
WSCL - Web Services Conversation Language
WSFL - Web Services Flow Language (superseded by BPEL)
XINS Standard Calling Convention - HTTP parameters in (GET/POST/HEAD), POX out
XLANG - XLANG-Specification (superseded by BPEL)
XML-RPC - XML Remote Procedure Call
See also
List of web service frameworks
List of web service specifications
Service-oriented architecture
Web service
Application layer protocols
web service |
https://en.wikipedia.org/wiki/Condensation%20algorithm | The condensation algorithm (Conditional Density Propagation) is a computer vision algorithm. The principal application is to detect and track the contour of objects moving in a cluttered environment. Object tracking is one of the more basic and difficult aspects of computer vision and is generally a prerequisite to object recognition. Being able to identify which pixels in an image make up the contour of an object is a non-trivial problem. Condensation is a probabilistic algorithm that attempts to solve this problem.
The algorithm itself is described in detail by Isard and Blake in a publication in the International Journal of Computer Vision in 1998. One of the most interesting facets of the algorithm is that it does not compute on every pixel of the image. Rather, pixels to process are chosen at random, and only a subset of the pixels end up being processed. Multiple hypotheses about what is moving are supported naturally by the probabilistic nature of the approach. The evaluation functions come largely from previous work in the area and include many standard statistical approaches. The original part of this work is the application of particle filter estimation techniques.
The algorithm’s creation was inspired by the inability of Kalman filtering to perform object tracking well in the presence of significant background clutter. The presence of clutter tends to produce probability distributions for the object state which are multi-modal and therefore poorly modeled by the Kalman filter. The condensation algorithm in its most general form requires no assumptions about the probability distributions of the object or measurements.
Algorithm overview
The condensation algorithm seeks to solve the problem of estimating the conformation of an object described by a vector at time , given observations of the detected features in the images up to and including the current time. The algorithm outputs an estimate to the state
conditional probability density by appl |
https://en.wikipedia.org/wiki/Graphic%20designer | A graphic designer is a professional within the graphic design and graphic arts industry who assembles together images, typography, or motion graphics to create a piece of design. A graphic designer creates the graphics primarily for published, printed, or electronic media, such as brochures and advertising. They are also sometimes responsible for typesetting, illustration, user interfaces. A core responsibility of the designer's job is to present information in a way that is both accessible and memorable.
Qualifications
Designers should be able to solve visual communication problems or challenges. In doing so, the designer must identify the communications issue, gather and analyze information related to the issue, and generate potential approaches aimed at solving the problem. Iterative prototyping and user testing can be used to determine the success or failure of a visual solution. Approaches to a communications problem are developed in the context of an audience and a media channel. Graphic designers must understand the social and cultural norms of that audience in order to develop visual solutions that are perceived as relevant, understandable and effective.
Graphic designers should also have a thorough understanding of production and rendering methods. Some of the technologies and methods of production are drawing, offset printing, photography, and time-based and interactive media (film, video, computer multimedia). Frequently, designers are also called upon to manage color in different media. For instance, graphic designers use different colors for digital and print advertisements. RGB - standing for red, green, blue - is an additive color model used for digital media designs. However, the CMYK color model is made up of subtractive colors - cyan, magenta, yellow, and black - and used in designing print media. The reason for the different models is that when designing print ads, colors look different on the screen and when printed onto paper. For example, |
https://en.wikipedia.org/wiki/Gerhard%20Ringel | Gerhard Ringel (October 28, 1919 in Kollnbrunn, Austria – June 24, 2008 in Santa Cruz, California) was a German mathematician. He was one of the pioneers in graph theory and contributed significantly to the proof of the Heawood conjecture (now the Ringel–Youngs theorem), a mathematical problem closely linked with the four color theorem.
Although born in Austria, Ringel was raised in Czechoslovakia and attended Charles University before being drafted into the Wehrmacht in 1940 (after Germany had taken control of much of what had been Czechoslovakia). After the war Ringel served for over four years in a Soviet prisoner of war camp.
He earned his PhD from the University of Bonn in 1951 with a thesis written under the supervision of Emanuel Sperner and Ernst Peschl. Ringel started his academic career as professor at the Free University Berlin. In 1970 he left Germany due to bureaucratic consequences of the German student movement, and continued his career at the University of California, Santa Cruz, having been invited there by his coauthor, John W. T. (Ted) Youngs. He was awarded honorary doctorate degrees from the Karlsruhe Institute of Technology and the Free University of Berlin.
Besides his mathematical skills he was a widely acknowledged entomologist. His main emphasis lay on collecting and breeding butterflies. Prior to his death, he gave his outstanding collection of butterflies to the UCSC Museum of Natural History Collections.
Publications |
https://en.wikipedia.org/wiki/Kripke%E2%80%93Platek%20set%20theory%20with%20urelements | The Kripke–Platek set theory with urelements (KPU) is an axiom system for set theory with urelements, based on the traditional (urelement-free) Kripke–Platek set theory. It is considerably weaker than the (relatively) familiar system ZFU. The purpose of allowing urelements is to allow large or high-complexity objects (such as the set of all reals) to be included in the theory's transitive models without disrupting the usual well-ordering and recursion-theoretic properties of the constructible universe; KP is so weak that this is hard to do by traditional means.
Preliminaries
The usual way of stating the axioms presumes a two sorted first order language with a single binary relation symbol .
Letters of the sort designate urelements, of which there may be none, whereas letters of the sort designate sets. The letters may denote both sets and urelements.
The letters for sets may appear on both sides of , while those for urelements may only appear on the left, i.e. the following are examples of valid expressions: , .
The statement of the axioms also requires reference to a certain collection of formulae called -formulae. The collection consists of those formulae that can be built using the constants, , , , , and bounded quantification. That is quantification of the form or where is given set.
Axioms
The axioms of KPU are the universal closures of the following formulae:
Extensionality:
Foundation: This is an axiom schema where for every formula we have .
Pairing:
Union:
Δ0-Separation: This is again an axiom schema, where for every -formula we have the following .
Δ0-SCollection: This is also an axiom schema, for every -formula we have .
Set Existence:
Additional assumptions
Technically these are axioms that describe the partition of objects into sets and urelements.
Applications
KPU can be applied to the model theory of infinitary languages. Models of KPU considered as sets inside a maximal universe that are transitive as such are called a |
https://en.wikipedia.org/wiki/Allan%20J.%20C.%20Cunningham | Allan Joseph Champneys Cunningham (1842–1928) was a British-Indian mathematician.
Biography
Born in Delhi, Cunningham was the son of Sir Alexander Cunningham, archaeologist and the founder of the Archaeological Survey of India. He started a military career with the East India Company's Bengal Engineers at a young age. From 1871 to 1881, he was instructor in mathematics at the Indian Institute Of Technology Roorkee (IIT Roorkee). Upon returning to the United Kingdom in 1881, he continued teaching at military institutes in Chatham, Dublin and Shorncliffe. He left the army in 1891. He spent the rest of his life studying number theory. He applied his expertise to finding factors of large numbers of the form an ± bn, such as Mersenne numbers () and Fermat numbers () which have b = 1. His work is continued in the Cunningham project. |
https://en.wikipedia.org/wiki/Cunningham%20Project | The Cunningham Project is a collaborative effort started in 1925 to factor numbers of the form bn ± 1 for b = 2, 3, 5, 6, 7, 10, 11, 12 and large n. The project is named after Allan Joseph Champneys Cunningham, who published the first version of the table together with Herbert J. Woodall. There are three printed versions of the table, the most recent published in 2002, as well as an online version by Samuel Wagstaff.
The current limits of the exponents are:
Factors of Cunningham number
Two types of factors can be derived from a Cunningham number without having to use a factorization algorithm: algebraic factors of binomial numbers (e.g. difference of two squares and sum of two cubes), which depend on the exponent, and aurifeuillean factors, which depend on both the base and the exponent.
Algebraic factors
From elementary algebra,
for all k, and
for odd k. In addition, b2n − 1 = (bn − 1)(bn + 1). Thus, when m divides n, bm − 1 and bm + 1 are factors of bn − 1 if the quotient of n over m is even; only the first number is a factor if the quotient is odd. bm + 1 is a factor of bn − 1, if m divides n and the quotient is odd.
In fact,
and
See this page for more information.
Aurifeuillean factors
When the number is of a particular form (the exact expression varies with the base), aurifeuillean factorization may be used, which gives a product of two or three numbers. The following equations give aurifeuillean factors for the Cunningham project bases as a product of F, L and M:
Let b = s2 × k with squarefree k, if one of the conditions holds, then have aurifeuillean factorization.
(i) and
(ii) and
Other factors
Once the algebraic and aurifeuillean factors are removed, the other factors of bn ± 1 are always of the form 2kn + 1, since they are all factors of . When n is prime, both algebraic and aurifeuillean factors are not possible, except the trivial factors (b − 1 for bn − 1 and b + 1 for bn + 1). For Mersenne numbers, the trivial factors are not poss |
https://en.wikipedia.org/wiki/BioHome | BioHome was a small facility created by NASA in the late 1980s that could support one person in a fully functional habitat. One of the influences on the project was the results from data obtained on the 1973 Skylab 3 (SL-3), where a total of 107 VOCs were offgassed by synthetic materials that composed the SL-3. However, the study of indoor air quality was not the only focus of the project, as it was a part of research into closed ecological life support systems.
The facility was still in use as of March 5, 2005, and has paved inroads into creating self-supporting life support systems.
Construction
Construction of the BioHome concluded in 1989 and construction materials included synthetics which gave off the aforementioned VOCs. The BioHome itself resembles a mobile home in size where it contained a living area and treatment facilities for human waste and air.
While not completely air-tight, such as the Biosphere 2 structure, the structure was engineered for maximum air and energy confinement. This was unsurprising, given that the interior walls were composed of molded plastic panels with 30 cm of fiberglass insulation.
The BioHome had living facilities that could support one person and foliage plants were placed throughout the structure, aiding in air purification. In addition to the plants, a prototype fan-assisted plant filter was installed; the filter had the removal capacity of 15 standard potted plants.
The BioHome was equipped with monitoring ports for the detection of VOCs, which were measured using mass spectrometer / gas chromatograph equipment.
In experiments regarding wastewater treatment, the facility was outfitted with PVC piping and ultraviolet equipment.
Usage
The BioHome was used for a variety of experiments into, and including:
Wastewater treatment
In its nascence, the BioHome focused on alternative, non-chemical sewage treatment methods utilizing non-edible plants of aquatic disposition. The aquatic and semi-aquatic plants were chos |
https://en.wikipedia.org/wiki/Plant%20senescence | Plant senescence is the process of aging in plants. Plants have both stress-induced and age-related developmental aging. Chlorophyll degradation during leaf senescence reveals the carotenoids, such as anthocyanin and xanthophylls, which are the cause of autumn leaf color in deciduous trees. Leaf senescence has the important function of recycling nutrients, mostly nitrogen, to growing and storage organs of the plant. Unlike animals, plants continually form new organs and older organs undergo a highly regulated senescence program to maximize nutrient export.
Hormonal regulation of senescence
Programmed senescence seems to be heavily influenced by plant hormones. The hormones abscisic acid, ethylene, jasmonic acid and salicylic acid are accepted by most scientists as promoters of senescence, but at least one source lists gibberellins, brassinosteroids and strigolactone as also being involved. Cytokinins help to maintain the plant cell and expression of cytokinin biosynthesis genes late in development prevents leaf senescence. A withdrawal of or inability of the cell to perceive cytokinin may cause it to undergo apoptosis or senescence. In addition, mutants that cannot perceive ethylene show delayed senescence. Genome-wide comparison of mRNAs expressed during dark-induced senescence versus those expressed during age-related developmental senescence demonstrate that jasmonic acid and ethylene are more important for dark-induced (stress-related) senescence while salicylic acid is more important for developmental senescence.
Annual versus perennial benefits
Some plants have evolved into annuals which die off at the end of each season and leave seeds for the next, whereas closely related plants in the same family have evolved to live as perennials. This may be a programmed "strategy" for the plants.
The benefit of an annual strategy may be genetic diversity, as one set of genes does continue year after year, but a new mix is produced each year. Secondly, being annual m |
https://en.wikipedia.org/wiki/John%20F.%20Allen%20%28physicist%29 | John Frank Allen, FRS FRSE (May 5, 1908 – April 22, 2001) was a Canadian-born physicist. At the same time as Pyotr Leonidovich Kapitsa in Moscow, Don Misener and Allen independently discovered the superfluid phase of matter in 1937 using liquid helium in the Royal Society Mond Laboratory in Cambridge, England.
Life
Allen was born in Winnipeg; he was also known as Jack Allen. His father, Frank Allen, was a professor in physics at the University of Manitoba.
John Allen studied physics initially at the University of Manitoba, where he received his bachelor's degree in 1928. Afterwards, he went to the University of Toronto to pursue postgraduate studies. He obtained his master's degree in 1930 and undertook his PhD working with John McLennan about superconductivity. He there developed and built his first cryostat which was taken by John McLennan for a demonstration of superconductivity in a public lecture to the Royal Institution in London. He obtained his PhD degree in 1933. With a two-year US National Research Council Fellowship which he obtained in 1933, he went to work as a postdoctoral researcher at Caltech between 1933 and 1935. In 1935, he joined the Mond Laboratory of the Royal Society in Cambridge to work with Pyotr Kapitsa on low temperature experiments. However, Kapitsa could not return from a visit of his mother in the Soviet Union in 1934 and never returned to Cambridge. So John Allen worked independently of Kapitsa on properties of helium at very low temperatures and published reports on the discovery of superfluidity in helium which were published side by side in Nature in January 1938. Despite the independent discovery at about the same time, the Nobel prize for Superfluidity was awarded only to Kapitsa in 1978.
He stayed in Cambridge until 1947, when he took up an appointment as a professor in natural philosophy at the University of St Andrews, Scotland in 1947.
In 1949, he was elected a Fellow of the Royal Society.
During his tenure at the Universi |
https://en.wikipedia.org/wiki/Don%20Misener | Don Misener (A.D. Misener) (1911–1996) was a physicist. Along with Pyotr Leonidovich Kapitsa and John F. Allen, Misener discovered the superfluid phase of matter in 1937.
Misener was a graduate student at the University of Toronto in 1935. He joined Allen at Cambridge University in about 1937. Misener later returned to Canada to work at the University of Western Ontario.
Journal references
E. F. Burton, J. O. Wilhelm, and A. D. Misener, Trans. Roy. Soc. Can. 28(111) p. 65 (1934)
J. F. Allen and A. D. Misener, Flow of Liquid Helium II, Nature 141(3558) p. 75 (8 Jan 1938)
A. D. Misener, The Specific Heat of Superconducting Mercury, Indium and Thallium, Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences, 174(957) pp. 262–272 (1940)
See also
Timeline of low-temperature technology
Allan Griffin A Brief History of Our Understanding of BEC: From Bose to Beliaev arXiv:cond-mat/9901123 p. 5 |
https://en.wikipedia.org/wiki/Behavior%20change%20%28public%20health%29 | Behavior change, in context of public health, refers to efforts put in place to change people's personal habits and attitudes, to prevent disease. Behavior change in public health can take place at several levels and is known as social and behavior change (SBC). More and more, efforts focus on prevention of disease to save healthcare care costs. This is particularly important in low and middle income countries, where supply side health interventions have come under increased scrutiny because of the cost.
Aims
The 3-4-50 concept outlines that there are 3 behaviors (poor diet, little to no physical activity, and smoking), that lead to four diseases (heart disease/stroke, diabetes, cancer, pulmonary disease), that account for 50% of deaths worldwide. This is why so much emphasis in public health interventions have been on changing behaviors or intervening early on to decrease the negative impacts that come with these behaviors. With successful intervention, there is the possibility of decreasing healthcare costs by a drastic amount, as well as general costs to society (morbidity and mortality). A good public health intervention is not only defined by the results they create, but also the number of levels it hits on the socioecological model (individual, interpersonal, community and/or environment). The challenge that public health interventions face is generalizability: what may work in one community may not work in others. However, there is the development of Healthy People 2020 that has national objectives aimed to accomplish in 10 years to improve the health of all Americans.
Health conditions and infections are associated with risky behaviors. Tobacco use, alcoholism, multiple sex partners, substance use, reckless driving, obesity, or unprotected sexual intercourse are some examples. Human beings have, in principle, control over their conduct. Behavior modification can contribute to the success of self-control, and health-enhancing behaviors. Risky behavior |
https://en.wikipedia.org/wiki/Conversion%20%28chemistry%29 | Conversion and its related terms yield and selectivity are important terms in chemical reaction engineering. They are described as ratios of how much of a reactant has reacted (X — conversion, normally between zero and one), how much of a desired product was formed (Y — yield, normally also between zero and one) and how much desired product was formed in ratio to the undesired product(s) (S — selectivity).
There are conflicting definitions in the literature for selectivity and yield, so each author's intended definition should be verified.
Conversion can be defined for (semi-)batch and continuous reactors and as instantaneous and overall conversion.
Assumptions
The following assumptions are made:
The following chemical reaction takes place:
,
where and are the stoichiometric coefficients. For multiple parallel reactions, the definitions can also be applied, either per reaction or using the limiting reaction.
Batch reaction assumes all reactants are added at the beginning.
Semi-Batch reaction assumes some reactants are added at the beginning and the rest fed during the batch.
Continuous reaction assumes reactants are fed and products leave the reactor continuously and in steady state.
Conversion
Conversion can be separated into instantaneous conversion and overall conversion. For continuous processes the two are the same, for batch and semi-batch there are important differences. Furthermore, for multiple reactants, conversion can be defined overall or per reactant.
Instantaneous conversion
Semi-batch
In this setting there are different definitions. One definition regards the instantaneous conversion as the ratio of the instantaneously converted amount to
the amount fed at any point in time:
.
with as the change of moles with time of species i.
This ratio can become larger than 1. It can be used to indicate whether reservoirs are built
up and it is ideally close to 1. When the feed stops, its value is not defined.
In semi-batch polymerisation, |
https://en.wikipedia.org/wiki/Electrostatic%20generator | An electrostatic generator, or electrostatic machine, is an electrical generator that produces static electricity, or electricity at high voltage and low continuous current. The knowledge of static electricity dates back to the earliest civilizations, but for millennia it remained merely an interesting and mystifying phenomenon, without a theory to explain its behavior and often confused with magnetism. By the end of the 17th century, researchers had developed practical means of generating electricity by friction, but the development of electrostatic machines did not begin in earnest until the 18th century, when they became fundamental instruments in the studies about the new science of electricity.
Electrostatic generators operate by using manual (or other) power to transform mechanical work into electric energy, or using electric currents. Manual electrostatic generators develop electrostatic charges of opposite signs rendered to two conductors, using only electric forces, and work by using moving plates, drums, or belts to carry electric charge to a high potential electrode.
Description
Electrostatic machines are typically used in science classrooms to safely demonstrate electrical forces and high voltage phenomena. The elevated potential differences achieved have been also used for a variety of practical applications, such as operating X-ray tubes, particle accelerators, spectroscopy, medical applications, sterilization of food, and nuclear physics experiments. Electrostatic generators such as the Van de Graaff generator, and variations as the Pelletron, also find use in physics research.
Electrostatic generators can be divided into categories depending on how the charge is generated:
Friction machines use the triboelectric effect (electricity generated by contact or friction)
Influence machines use electrostatic induction
Others
Friction machines
History
The first electrostatic generators are called friction machines because of the friction in the genera |
https://en.wikipedia.org/wiki/Gilliflower | A gilliflower or gillyflower () is:
The carnation or a similar plant of the genus Dianthus, especially the Clove Pink Dianthus caryophyllus.
Matthiola incana, also known as stock.
Several other plants, such as the wallflower, which have fragrant flowers.
The name derives from the French giroflée from Greek karyophyllon = "nut-leaf" = the spice called clove, the association deriving from the flower's scent.
Gilliflowers have been claimed to be used as payment for peppercorn rent in medieval feudal tenure contracts. For example, in 1262 in Bedfordshire an area of land called The Hyde was held by someone "for the rent of one clove of gilliflower", and Elmore Court in Gloucester was granted to the Guise family by John De Burgh for the rent of "The clove of one Gillyflower" each year. In Kent in the 13th century Bartholomew de Badlesmere upon an exchange made between King Edward I and himself, received a royal grant in fee of a manor and chapel, to hold in socage, "by the service of paying one pair of clove gilliflowers", by the hands of the Sheriff. However, it is more likely that the rent was paid in the form of actual cloves (in Latin, gariofilum; the flower was later named after the spice, via French), cloves and peppercorns both being exotic spices.
The rose and gillyflower appear on the station badge of RAF Waterbeach in Cambridgeshire, and subsequently on the badge of 39 Engineer Regiment based at Waterbeach Barracks. A rose and gillyflower were demanded by the owner of the land on which Waterbeach Abbey was built, in the 12th century.
An old recipe for gilliflower wine is mentioned in the Cornish Recipes Ancient & Modern dated to 1753:
Gilliflowers are mentioned by Mrs. Lovett in the song "Wait" from the Sondheim musical Sweeney Todd and in the novel La Faute de l'Abbé Mouret (aka Abbe Mouret's Transgression or the Sin of the Father Mouret) by Émile Zola as part of the Les Rougon-Macquart series. Charles Ryder has them growing under his window when he is a |
https://en.wikipedia.org/wiki/Hilbert%27s%20fourth%20problem | In mathematics, Hilbert's fourth problem in the 1900 list of Hilbert's problems is a foundational question in geometry. In one statement derived from the original, it was to find — up to an isomorphism — all geometries that have an axiomatic system of the classical geometry (Euclidean, hyperbolic and elliptic), with those axioms of congruence that involve the concept of the angle dropped, and `triangle inequality', regarded as an axiom, added.
If one assumes the continuity axiom in addition, then, in the case of the Euclidean plane, we come to the problem posed by Jean Gaston Darboux: "To determine all the calculus of variation problems in the plane whose solutions are all the plane straight lines."
There are several interpretations of the original statement of David Hilbert. Nevertheless, a solution was sought, with the German mathematician Georg Hamel being the first to contribute to the solution of Hilbert's fourth problem.
A recognized solution was given by Soviet mathematician Aleksei Pogorelov in 1973.<ref name="Pogorelov1973">А. В. Погорелов, Полное решение IV проблемы Гильберта, ДАН СССР № 208, т.1 (1973), 46–49. English translation: {{cite journal
| last1=Pogorelov | first1=A. V.
| title=A complete solution of "Hilbert's fourth problem| journal=Doklady Akademii Nauk SSSR
| volume=208
| issue=1
| date=1973
| pages=48–52}}</ref> In 1976, Armenian mathematician Rouben V. Ambartzumian proposed another proof of Hilbert's fourth problem.
Original statement
Hilbert discusses the existence of non-Euclidean geometry and non-Archimedean geometry
...a geometry in which all the axioms of ordinary euclidean geometry hold, and in particular all the congruence axioms except the one of the congruence of triangles (or all except the theorem of the equality of the base angles in the isosceles triangle), and in which, besides, the proposition that in every triangle the sum of two sides is greater than the third is assumed as a particular axiom.
Due to the idea that a |
https://en.wikipedia.org/wiki/Tanystropheus | Tanystropheus (~ 'long' + 'hinged') is an extinct genus of archosauromorph reptile which lived during the Triassic Period in Europe, Asia, and North America. It is recognisable by its extremely elongated neck, longer than the torso and tail combined. The neck was composed of 13 vertebrae strengthened by extensive cervical ribs. Tanystropheus is one of the most well-described non-archosauriform archosauromorphs, known from numerous fossils, including nearly complete skeletons. Some species within the genus may have reached a total length of , making Tanystropheus the longest non-archosauriform archosauromorph as well. Tanystropheus is the namesake of the family Tanystropheidae, a clade collecting many long-necked Triassic archosauromorphs previously described as "protorosaurs" or "prolacertiforms".
Tanystropheus contains at least two valid species as well as fossils which cannot be referred to a specific species. The type species of Tanystropheus is T. conspicuus, a dubious name applied to particularly large fossils from Germany and Poland. Complete skeletons are common in the Besano Formation at Monte San Giorgio, on the border of Italy and Switzerland. Monte San Giorgio fossils belong to two species: the smaller T. longobardicus and the larger T. hydroides. These two species were formally differentiated in 2020 primarily on the basis of their strongly divergent skull anatomy. When T. longobardicus was first described in 1886, it was initially mistaken for a pterosaur and given the name "Tribelesodon". Starting in the 1920s, systematic excavations at Monte San Giorgio unearthed many more Tanystropheus fossils, revealing that the putative wing bones of "Tribelesodon" were actually neck vertebrae.
Most Tanystropheus fossils hail from marine or coastal deposits of the Middle Triassic epoch (Anisian and Ladinian stages), with some exceptions. For example, a vertebra from Nova Scotia was recovered from primarily freshwater sediments. The youngest fossils in the genus |
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