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Experimental philosophy Problem of reproducibility Experimental_philosophy > Criticisms > Problem of reproducibility Since publication of Seyedsayamdost's papers, Stich and collaborators have reversed their research direction on this question. The reason for these problems in experimental philosophy is not entirely clear, although a parallel with experimental psychology has been suggested.At least one recent study, in which a team attempted to replicate various influential studies in experimental philosophy studies, found that roughly 70% of them could be replicated. The reasons for the discrepancy with Seyedsayamdost's original study are not yet known.
DNS hijacking Technical background DNS_hijacking > Technical background One of the functions of a DNS server is to translate a domain name into an IP address that applications need to connect to an Internet resource such as a website. This functionality is defined in various formal internet standards that define the protocol in considerable detail. DNS servers are implicitly trusted by internet-facing computers and users to correctly resolve names to the actual addresses that are registered by the owners of an internet domain.
Circular notation Permutations of totally ordered sets One-line_notation > Permutations of totally ordered sets In some applications, the elements of the set being permuted will be compared with each other. This requires that the set S has a total order so that any two elements can be compared. The set {1, 2, ..., n} is totally ordered by the usual "≤" relation and so it is the most frequently used set in these applications, but in general, any totally ordered set will do. In these applications, the ordered arrangement view of a permutation is needed to talk about the positions in a permutation. There are a number of properties that are directly related to the total ordering of S.
Strain rate imaging Basic concepts Strain_rate_imaging > Basic concepts This method, however, yields the Eulerian strain rate and strain. It has become traditional to use the Velocity gradient, but in integrating strain rate it is converted to Lagrangian strain by the formula εL = eεE - 1.Strain in three dimensions: Basically, any object or body is three dimensional, and can be deformed in different directions simultaneously. Strain can be described as a tensor with three principal strains (εx, εy and εz in a Cartesian coordinate system), and six shear strains components.
LogP machine Summary LogP_machine The LogP machine consists of arbitrarily many processing units with distributed memory. The processing units are connected through an abstract communication medium which allows point-to-point communication. This model is pair-wise synchronous and overall asynchronous.
Biological inheritance Modern development of genetics and heredity Heredity > History > Modern development of genetics and heredity The role of genetic drift is equivocal; though strongly supported initially by Dobzhansky, it was downgraded later as results from ecological genetics were obtained. The primacy of population thinking: the genetic diversity carried in natural populations is a key factor in evolution. The strength of natural selection in the wild was greater than expected; the effect of ecological factors such as niche occupation and the significance of barriers to gene flow are all important.The idea that speciation occurs after populations are reproductively isolated has been much debated.
Variable data publishing Summary Variable_data_publishing The possibilities are vast. The variable-data tools available today, make it possible to perform variable-data composition at nearly every stage of document production. However, the level of control that can be achieved varies, based upon how far into the document production process a variable-data tool is deployed.
Euler–Bernoulli beam equation History Beam_theory > History Prevailing consensus is that Galileo Galilei made the first attempts at developing a theory of beams, but recent studies argue that Leonardo da Vinci was the first to make the crucial observations. Da Vinci lacked Hooke's law and calculus to complete the theory, whereas Galileo was held back by an incorrect assumption he made.The Bernoulli beam is named after Jacob Bernoulli, who made the significant discoveries. Leonhard Euler and Daniel Bernoulli were the first to put together a useful theory circa 1750.
Bondi k-calculus The twins paradox Bondi_k-calculus > The twins paradox In Newtonian physics, the expectation would be that, at the final comparison, Alice's and Carol's clock would agree, t C = t A {\displaystyle t_{C}=t_{A}} . It will be shown below that in relativity this is not true. This is a version of the well-known "twins paradox" in which identical twins separate and reunite, only to find that one is now older than the other.
Revive & Restore Catalyst Science Fund Revive_&_Restore > Programs > Catalyst Science Fund The Catalyst Science Fund supports the development of new biotechnology tools for conservation. Launched in 2018 and now over $8 million, the Catalyst Science Fund targets early-stage bioscience research and proof-of-concept projects with the potential to impact conservation. Funded programs include the Advanced Coral Toolkit and Wild Genomes described below, among others.
Reaction Calorimeter Heat flow calorimetry Reaction_calorimeters > Heat flow calorimetry Heat flow calorimetry measures the heat flowing across the reactor wall and quantifying this in relation to the other energy flows within the reactor. Q = U A ( T r − T j ) {\displaystyle Q=UA(T_{r}-T_{j})} where Q {\displaystyle Q} = process heating (or cooling) power (W) U {\displaystyle U} = overall heat transfer coefficient (W/(m2K)) A {\displaystyle A} = heat transfer area (m2) T r {\displaystyle T_{r}} = process temperature (K) T j {\displaystyle T_{j}} = jacket temperature (K)Heat flow calorimetry allows the user to measure heat whilst the process temperature remains under control. While the driving force Tr − Tj is measured with a relatively high resolution, the overall heat transfer coefficient U or the calibration factor UA respectively, is determined by means of calibration before and after the reaction takes place. The calibration factor UA (or the overall heat transfer coefficient U) are affected by the product composition, process temperature, agitation rate, viscosity, and the liquid level. Good accuracy can be achieved with experienced staff who know the limitations and how to get the best results from an instrument.
BRST charge Gauge transformations in QFT BRST_quantization > Gauge transformations in QFT It has proven rather more difficult to prove the existence of non-Abelian quantum field theory in a rigorous sense than to obtain accurate predictions using semi-heuristic calculation schemes. This is because analyzing a quantum field theory requires two mathematically interlocked perspectives: a Lagrangian system based on the action functional, composed of fields with distinct values at each point in spacetime and local operators which act on them, and a Hamiltonian system in the Dirac picture, composed of states which characterize the entire system at a given time and field operators which act on them. What makes this so difficult in a gauge theory is that the objects of the theory are not really local fields on spacetime; they are right-invariant local fields on the principal gauge bundle, and different local sections through a portion of the gauge bundle, related by passive transformations, produce different Dirac pictures.
Negacyclic convolution Summary Negacyclic_convolution In mathematics, negacyclic convolution is a convolution between two vectors a and b. It is also called skew circular convolution or wrapped convolution. It results from multiplication of a skew circulant matrix, generated by vector a, with vector b.
Naïve Bayes classifier Document classification Naive_Bayes_classifier > Examples > Document classification The actual probability p(S \| D) can be easily computed from log (p(S \| D) / p(¬S \| D)) based on the observation that p(S \| D) + p(¬S \| D) = 1. Taking the logarithm of all these ratios, one obtains: ln ⁡ p ( S ∣ D ) p ( ¬ S ∣ D ) = ln ⁡ p ( S ) p ( ¬ S ) + ∑ i ln ⁡ p ( w i ∣ S ) p ( w i ∣ ¬ S ) {\displaystyle \ln {p(S\mid D) \over p(\neg S\mid D)}=\ln {p(S) \over p(\neg S)}+\sum _{i}\ln {p(w_{i}\mid S) \over p(w_{i}\mid \neg S)}} (This technique of "log-likelihood ratios" is a common technique in statistics.
Biogeography-based optimization Summary Biogeography-based_optimization Biogeography-based optimization (BBO) is an evolutionary algorithm (EA) that optimizes a function by stochastically and iteratively improving candidate solutions with regard to a given measure of quality, or fitness function. BBO belongs to the class of metaheuristics since it includes many variations, and since it does not make any assumptions about the problem and can therefore be applied to a wide class of problems. BBO is typically used to optimize multidimensional real-valued functions, but it does not use the gradient of the function, which means that it does not require the function to be differentiable as required by classic optimization methods such as gradient descent and quasi-newton methods. BBO can therefore be used on discontinuous functions.
Polygon graphics Geometric theory and polygons Polygonal_modeling > Geometric theory and polygons In Euclidean geometry, any three non-collinear points determine a plane. For this reason, triangles always inhabit a single plane. This is not necessarily true of more complex polygons, however.
Free electron pair Different descriptions for multiple lone pairs Lone_electron_pair > Different descriptions for multiple lone pairs In elementary chemistry courses, the lone pairs of water are described as "rabbit ears": two equivalent electron pairs of approximately sp3 hybridization, while the HOH bond angle is 104.5°, slightly smaller than the ideal tetrahedral angle of arccos(–1/3) ≈ 109.47°. The smaller bond angle is rationalized by VSEPR theory by ascribing a larger space requirement for the two identical lone pairs compared to the two bonding pairs. In more advanced courses, an alternative explanation for this phenomenon considers the greater stability of orbitals with excess s character using the theory of isovalent hybridization, in which bonds and lone pairs can be constructed with spx hybrids wherein nonintegral values of x are allowed, so long as the total amount of s and p character is conserved (one s and three p orbitals in the case of second-row p-block elements). To determine the hybridization of oxygen orbitals used to form the bonding pairs and lone pairs of water in this picture, we use the formula 1 + x cos θ = 0, which relates bond angle θ with the hybridization index x. According to this formula, the O–H bonds are considered to be constructed from O bonding orbitals of ~sp4.0 hybridization (~80% p character, ~20% s character), which leaves behind O lone pairs orbitals of ~sp2.3 hybridization (~70% p character, ~30% s character).
Industrial scale General and cited references Economies_of_scale > References > General and cited references Morroni, Mario (2006). Knowledge, Scale and Transactions in the Theory of the Firm. Cambridge: Cambridge University Press.
Antibiotic use in dentistry Common antibiotics used in Dentistry Antibiotic_use_in_dentistry > Common antibiotics used in Dentistry In the UK, it has effective use in dentistry as it is the primary drug prescribed for acute ulcerative gingivitis. It is also sometimes used either alongside penicillin or alone against dentoalveolar infections with the advantage of having a low allergenicity. Mild side effects of metronidazole include transient rashes, furred tongue, an unpleasant taste in the mouth alongside several other side effects not restricted to the oral cavity.Sulphonamides: This a group of drugs which is used in dentistry as they have a major advantage of being able to penetrate cerebrospinal fluid and this is particularly relevant when prescribing antibiotics, prophylactically against bacterial meningitis in patients who have had severe maxillofacial injuries, where the risk of infection is high.
Ballistic impact Summary Ballistic_impact Ballistic impact is a high velocity impact by a small mass object, analogous to runway debris or small arms fire. The simulation of ballistic impacts can be achieved with a light-gas gun or other ballistic launcher. It is important to study the response of materials to ballistic impact loads. Applications of this research include body armor, armored vehicles and fortified buildings, as well as the protection of essential equipment, such as the jet engines of an airliner.
Envelope proteins Summary Envelope_proteins TAM receptors, which are potential targets for therapy, are thereby activated by viruses to reduce type I IFN signaling. Glycoproteins on the surface of the envelope serve to identify and bind to receptor sites on the host's membrane. The particular set of viral proteins are engaged in a series of structural changes.
Mature protein Case examples Mature_protein > Case examples Cleavage and formation of disulfide bridges during the production of insulin PTM of histones as regulation of transcription: RNA polymerase control by chromatin structure PTM of RNA polymerase II as regulation of transcription Cleavage of polypeptide chains as crucial for lectin specificity
Level ancestor problem Stage 1: long-path decomposition Level_ancestor_problem > Ladder algorithm > Stage 1: long-path decomposition However, after this pre-processing stage, the queries cannot be answered quickly. In fact in order to answer a level ancestor query, the algorithm needs to jump from a path to another until it reaches the root and there could be Θ(√n) of such paths on a leaf-to-root path. This leads us to an algorithm that can pre-process the tree in O(n) time and answers queries in O(√n). In order to reach the optimal query time, we need to process the results in a second stage described below.
Microwave power meter Thermal Microwave_power_meter > Sensor technologies > Thermal Thermocouple power sensors make up the majority of the thermal power sensors sold at present. They are generally reasonably linear and have a reasonably fast response time and dynamic range. The microwave power is absorbed in a load whose temperature rise is measured by the thermocouple.
Right division Abstract algebra Division_(mathematics) > Division in different contexts > Abstract algebra A quasigroup is a structure in which division is always possible, even without an identity element and hence inverses. In an integral domain, where not every element need have an inverse, division by a cancellative element a can still be performed on elements of the form ab or ca by left or right cancellation, respectively. If a ring is finite and every nonzero element is cancellative, then by an application of the pigeonhole principle, every nonzero element of the ring is invertible, and division by any nonzero element is possible. To learn about when algebras (in the technical sense) have a division operation, refer to the page on division algebras. In particular Bott periodicity can be used to show that any real normed division algebra must be isomorphic to either the real numbers R, the complex numbers C, the quaternions H, or the octonions O.
Probability metric Generalized metrics Probability_metric > Distances as metrics > Generalized metrics Many statistical distances are not metrics, because they lack one or more properties of proper metrics. For example, pseudometrics violate property (2), identity of indiscernibles; quasimetrics violate property (3), symmetry; and semimetrics violate property (4), the triangle inequality. Statistical distances that satisfy (1) and (2) are referred to as divergences.
Propositional satisfiability Summary Boolean_Satisfiability In logic and computer science, the Boolean satisfiability problem (sometimes called propositional satisfiability problem and abbreviated SATISFIABILITY, SAT or B-SAT) is the problem of determining if there exists an interpretation that satisfies a given Boolean formula. In other words, it asks whether the variables of a given Boolean formula can be consistently replaced by the values TRUE or FALSE in such a way that the formula evaluates to TRUE. If this is the case, the formula is called satisfiable. On the other hand, if no such assignment exists, the function expressed by the formula is FALSE for all possible variable assignments and the formula is unsatisfiable.
Glossary of chemistry terms M Glossary_of_chemistry_terms > M molar mass Sometimes used interchangeably with molecular weight and formula weight. For a given chemical compound, the mass of a sample of that compound divided by the amount of compound in the sample, usually expressed in grams per mole (g/mol). As a bulk property, molar mass is an average of the masses of many instances of the compound, each of which may vary slightly due to the presence of isotopes of the compound's constituent atoms; it is commonly derived from the compound's molecular weight, which itself is a sum of the standard atomic weights of the constituent atoms, and is therefore a function of the relative abundance of the isotopes as they occur naturally on Earth.
Numerical solution of the convection–diffusion equation Finite element solution to convection–diffusion problem Numerical_solution_of_the_convection–diffusion_equation > Finite element solution to convection–diffusion problem The finite difference scheme has an equivalent in the finite element method (Galerkin method). Another similar method is the characteristic Galerkin method (which uses an implicit algorithm). For scalar variables, the above two methods are identical.
Ribosomal binding site Summary Ribosome_binding_site A ribosome binding site, or ribosomal binding site (RBS), is a sequence of nucleotides upstream of the start codon of an mRNA transcript that is responsible for the recruitment of a ribosome during the initiation of translation. Mostly, RBS refers to bacterial sequences, although internal ribosome entry sites (IRES) have been described in mRNAs of eukaryotic cells or viruses that infect eukaryotes. Ribosome recruitment in eukaryotes is generally mediated by the 5' cap present on eukaryotic mRNAs.
Functional integral Summary Functional_integration For each function, the integrand returns a value to add up. Making this procedure rigorous poses challenges that continue to be topics of current research.
Isotopes of oganesson Summary Isotopes_of_oganesson Oganesson (118Og) is a synthetic element created in particle accelerators, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first and only isotope to be synthesized was 294Og in 2002 and 2005; it has a half-life of 700 microseconds.
Galois/Counter Mode Mathematical basis Galois_Message_Authentication_Code > Mathematical basis GCM combines the well-known counter mode of encryption with the new Galois mode of authentication. The key feature is the ease of parallel computation of the Galois field multiplication used for authentication. This feature permits higher throughput than encryption algorithms, like CBC, which use chaining modes. The GF(2128) field used is defined by the polynomial x 128 + x 7 + x 2 + x + 1 {\displaystyle x^{128}+x^{7}+x^{2}+x+1} The authentication tag is constructed by feeding blocks of data into the GHASH function and encrypting the result.
Philosophiæ Naturalis Principia Mathematica Book 2, part 2 of De motu corporum Philosophiæ_Naturalis_Principia_Mathematica > Contents > Book 2, part 2 of De motu corporum Newton compares the resistance offered by a medium against motions of globes with different properties (material, weight, size). In Section 8, he derives rules to determine the speed of waves in fluids and relates them to the density and condensation (Proposition 48; this would become very important in acoustics).
Database scalability Horizontal Database_scalability > Dimensions > Horizontal Horizontal database scaling involves adding more servers to work on a single workload. Most horizontally scalable systems come with functionality compromises. If an application requires more functionality, migration to a vertically scaled system may be preferable.
Mutual recursion Prevalence Mutual_recursion > Prevalence Mutual recursion is very common in functional programming, and is often used for programs written in LISP, Scheme, ML, and similar programming languages. For example, Abelson and Sussman describe how a meta-circular evaluator can be used to implement LISP with an eval-apply cycle. In languages such as Prolog, mutual recursion is almost unavoidable.
100% renewable energy Energy transition 100%_renewable_energy > Feasibility > Energy transition 100% renewable energy is an energy system where all energy use is sourced from renewable energy sources. The endeavor to use 100% renewable energy for electricity, heating/cooling and transport is motivated by global warming, pollution and other environmental issues, as well as economic and energy security concerns. Shifting the total global primary energy supply to renewable sources requires a transition of the energy system, since most of today's energy is derived from non-renewable fossil fuels. According to the Intergovernmental Panel on Climate Change there are few fundamental technological limits to integrating a portfolio of renewable energy technologies to meet most of total global energy demand.
T Symmetry General references Time-reversal_invariance > References > General references Maxwell's demon: entropy, information, computing, edited by H.S.Leff and A.F. Rex (IOP publishing, 1990) ISBN 0-7503-0057-4 Maxwell's demon, 2: entropy, classical and quantum information, edited by H.S.Leff and A.F. Rex (IOP publishing, 2003) ISBN 0-7503-0759-5 The emperor's new mind: concerning computers, minds, and the laws of physics, by Roger Penrose (Oxford university press, 2002) ISBN 0-19-286198-0 Sozzi, M.S. (2008).
Dynamical system (definition) Construction of dynamical systems Dynamic_systems > Construction of dynamical systems The concept of evolution in time is central to the theory of dynamical systems as seen in the previous sections: the basic reason for this fact is that the starting motivation of the theory was the study of time behavior of classical mechanical systems. But a system of ordinary differential equations must be solved before it becomes a dynamic system. For example consider an initial value problem such as the following: x ˙ = v ( t , x ) {\displaystyle {\dot {\boldsymbol {x}}}={\boldsymbol {v}}(t,{\boldsymbol {x}})} x \| t = 0 = x 0 {\displaystyle {\boldsymbol {x}}\|_{t=0}={\boldsymbol {x}}_{0}} where x ˙ {\displaystyle {\dot {\boldsymbol {x}}}} represents the velocity of the material point x M is a finite dimensional manifold v: T × M → TM is a vector field in Rn or Cn and represents the change of velocity induced by the known forces acting on the given material point in the phase space M. The change is not a vector in the phase space M, but is instead in the tangent space TM.There is no need for higher order derivatives in the equation, nor for the parameter t in v(t,x), because these can be eliminated by considering systems of higher dimensions.
Infinite sequence Finite and infinite Mathematical_sequence > Formal definition and basic properties > Finite and infinite Such a sequence is called a singly infinite sequence or a one-sided infinite sequence when disambiguation is necessary. In contrast, a sequence that is infinite in both directions—i.e.
Archaea Cell wall and archaella Archaea > Structure, composition development, and operation > Cell wall and archaella Unlike bacteria, archaea lack peptidoglycan in their cell walls. Methanobacteriales do have cell walls containing pseudopeptidoglycan, which resembles eubacterial peptidoglycan in morphology, function, and physical structure, but pseudopeptidoglycan is distinct in chemical structure; it lacks D-amino acids and N-acetylmuramic acid, substituting the latter with N-Acetyltalosaminuronic acid.Archaeal flagella are known as archaella, that operate like bacterial flagella – their long stalks are driven by rotatory motors at the base.
Tides in marginal seas Tidal propagation along coasts Tides_in_marginal_seas > Tidal propagation along coasts After entering the continental shelf, a tidal wave quickly faces a boundary in the form of a landmass. When the tidal wave reaches a continental margin, it continues as a boundary trapped Kelvin wave. Along the coast, a boundary trapped Kelvin is also known as a coastal Kelvin wave or Edge wave. A Kelvin wave is a special type of gravity wave that can exist when there is (1) gravity and stable stratification, (2) sufficient Coriolis force and (3) the presence of a vertical boundary.
Passive dynamics Summary Passive_dynamics Passive dynamics refers to the dynamical behavior of actuators, robots, or organisms when not drawing energy from a supply (e.g., batteries, fuel, ATP). Depending on the application, considering or altering the passive dynamics of a powered system can have drastic effects on performance, particularly energy economy, stability, and task bandwidth. Devices using no power source are considered "passive", and their behavior is fully described by their passive dynamics.
Diaphragmatic surface of heart Cardiac output Right_heart > Physiology > Blood flow > Cardiac output It can be influenced by narrowing of the heart valves (stenosis) or contraction or relaxation of the peripheral blood vessels.The strength of heart muscle contractions controls the stroke volume. This can be influenced positively or negatively by agents termed inotropes. These agents can be a result of changes within the body, or be given as drugs as part of treatment for a medical disorder, or as a form of life support, particularly in intensive care units. Inotropes that increase the force of contraction are "positive" inotropes, and include sympathetic agents such as adrenaline, noradrenaline and dopamine. "Negative" inotropes decrease the force of contraction and include calcium channel blockers.
Computer models of musical creativity Visual and artistic creativity Computational_creativity > Visual and artistic creativity Nonetheless, The Painting Fool has been extended to create novel images, much as AARON does, from its own limited imagination. Images in this vein include cityscapes and forests, which are generated by a process of constraint satisfaction from some basic scenarios provided by the user (e.g., these scenarios allow the system to infer that objects closer to the viewing plane should be larger and more color-saturated, while those further away should be less saturated and appear smaller). Artistically, the images now created by the Painting Fool appear on a par with those created by Aaron, though the extensible mechanisms employed by the former (constraint satisfaction, etc.) may well allow it to develop into a more elaborate and sophisticated painter.
Row-column FFT algorithm Other generalizations Fast_Fourier_Transform > Other generalizations Various groups have also published "FFT" algorithms for non-equispaced data, as reviewed in Potts et al. (2001). Such algorithms do not strictly compute the DFT (which is only defined for equispaced data), but rather some approximation thereof (a non-uniform discrete Fourier transform, or NDFT, which itself is often computed only approximately). More generally there are various other methods of spectral estimation.
Causal relationships Buddhist philosophy Cause_and_effect > History > Buddhist philosophy In contrast, simultaneous cause and effect rejectors say that if the effect already exists, then it cannot effect the same way again. How past, present and future are accepted is a basis for various Buddhist school's causality viewpoints.All the classic Buddhist schools teach karma. "The law of karma is a special instance of the law of cause and effect, according to which all our actions of body, speech, and mind are causes and all our experiences are their effects."
Impossibility proof Impossible constructions sought by the ancient Greeks Impossibility_proof > Impossible constructions sought by the ancient Greeks Three famous questions of Greek geometry were how: to trisect any angle using a compass and a straightedge, to construct a cube with a volume twice the volume of a given cube, to construct a square equal in area to that of a given circle.For more than 2,000 years unsuccessful attempts were made to solve these problems; at last, in the 19th century it was proved that the desired constructions are logically impossible.A fourth problem of the ancient Greeks was to construct an equilateral polygon with a specified number n of sides, beyond the basic cases n = 3, 4, 5, 6 that they knew how to construct. All of these are problems in Euclidean construction, and Euclidean constructions can be done only if they involve only Euclidean numbers (by definition of the latter). Irrational numbers can be Euclidean. A good example is the square root of 2 (an irrational number). It is simply the length of the hypotenuse of a right triangle with legs both one unit in length, and it can be constructed with a straightedge and a compass. But it was proved centuries after Euclid that Euclidean numbers cannot involve any operations other than addition, subtraction, multiplication, division, and the extraction of square roots.
Theory of gravity Historical alternative theories Force_of_gravity > Alternative theories > Historical alternative theories Aristotelian theory of gravity Le Sage's theory of gravitation (1784) also called LeSage gravity but originally proposed by Fatio and further elaborated by Georges-Louis Le Sage, based on a fluid-based explanation where a light gas fills the entire Universe. Ritz's theory of gravitation, Ann. Chem. Phys.
Greenhouse gas monitoring Atmospheric Chemistry Experiment‐Fourier Transform Spectrometer (ACE-FTS) Greenhouse_gas_monitoring > Methodology > Nitrous oxide monitoring > Atmospheric Chemistry Experiment‐Fourier Transform Spectrometer (ACE-FTS) Nitrous oxide is one of the most prominent anthropogenic ozone-depleting gases in the atmosphere. It is released into the atmosphere primarily through natural sources such as soil and rock, as well as anthropogenic process like farming. Atmospheric nitrous oxide is also created in the atmosphere as a product of a reaction between nitrogen and electronically excited ozone in the lower thermosphere. The Atmospheric Chemistry Experiment‐Fourier Transform Spectrometer (ACE-FTS) is a tool used for measuring nitrous oxide concentrations in the upper to lower troposphere.
Provably secure Practice-oriented provable security Security_proof > In cryptography > Practice-oriented provable security Classical provable security primarily aimed at studying the relationship between asymptotically defined objects. Instead, practice-oriented provable security is concerned with concrete objects of cryptographic practice, such as hash functions, block ciphers, and protocols as they are deployed and used. Practice oriented provable security uses concrete security to analyse practical constructions with fixed key sizes. "Exact security" or "concrete security" is the name given to provable security reductions where one quantifies security by computing precise bounds on computational effort, rather than an asymptotic bound which is guaranteed to hold for "sufficiently large" values of the security parameter. == References ==
Liouville quantum gravity WZW models Liouville_quantum_gravity > Relations with other conformal field theories > WZW models Liouville theory can be obtained from the S L 2 ( R ) {\displaystyle SL_{2}(\mathbb {R} )} Wess–Zumino–Witten model by a quantum Drinfeld–Sokolov reduction. Moreover, correlation functions of the H 3 + {\displaystyle H_{3}^{+}} model (the Euclidean version of the S L 2 ( R ) {\displaystyle SL_{2}(\mathbb {R} )} WZW model) can be expressed in terms of correlation functions of Liouville theory. This is also true of correlation functions of the 2d black hole S L 2 / U 1 {\displaystyle SL_{2}/U_{1}} coset model. Moreover, there exist theories that continuously interpolate between Liouville theory and the H 3 + {\displaystyle H_{3}^{+}} model.
Hypohidrosis Management Hypohidrosis > Management In acquired generalized anhidrosis, spontaneous remission may be observed in some cases. Numerous cases have been reported to respond effectively to systemic corticosteroids. Although an optimum dose and regime has not been established, pulse methylprednisolone (up to 1000 mg/day) has been reported to have good effect.
Compound distribution Definition Compound_probability_distribution > Definition A compound probability distribution is the probability distribution that results from assuming that a random variable X {\displaystyle X} is distributed according to some parametrized distribution F {\displaystyle F} with an unknown parameter θ {\displaystyle \theta } that is again distributed according to some other distribution G {\displaystyle G} . The resulting distribution H {\displaystyle H} is said to be the distribution that results from compounding F {\displaystyle F} with G {\displaystyle G} . The parameter's distribution G {\displaystyle G} is also called the mixing distribution or latent distribution. Technically, the unconditional distribution H {\displaystyle H} results from marginalizing over G {\displaystyle G} , i.e., from integrating out the unknown parameter(s) θ {\displaystyle \theta } .
Stress testing (software) Examples Stress_testing_(software) > Examples A web server may be stress tested using scripts, bots, and various denial of service tools to observe the performance of a web site during peak loads.
Newton's Third Law Third law Newton's_First_Law > Laws > Third law In Newtonian mechanics, if two bodies have momenta p → 1 {\displaystyle {\vec {p}}_{1}} and p → 2 {\displaystyle {\vec {p}}_{2}} respectively, then the total momentum of the pair is p → = p → 1 + p → 2 {\displaystyle {\vec {p}}={\vec {p}}_{1}+{\vec {p}}_{2}} , and the rate of change of p → {\displaystyle {\vec {p}}} is By Newton's second law, the first term is the total force upon the first body, and the second term is the total force upon the second body. If the two bodies are isolated from outside influences, the only force upon the first body can be that from the second, and vice versa. By Newton's third law, these forces have equal magnitude but opposite direction, so they cancel when added, and p → {\displaystyle {\vec {p}}} is constant. Alternatively, if p → {\displaystyle {\vec {p}}} is known to be constant, it follows that the forces have equal magnitude and opposite direction.
Photoplethysmograph Monitoring respiration Photoplethysmograph > Uses > Monitoring respiration Respiration affects the cardiac cycle by varying the intrapleural pressure, the pressure between the thoracic wall and the lungs. Since the heart resides in the thoracic cavity between the lungs, the partial pressure of inhaling and exhaling greatly influence the pressure on the vena cava and the filling of the right atrium. During inspiration, intrapleural pressure decreases by up to 4 mm Hg, which distends the right atrium, allowing for faster filling from the vena cava, increasing ventricular preload, but decreasing stroke volume. Conversely during expiration, the heart is compressed, decreasing cardiac efficiency and increasing stroke volume. When the frequency and depth of respiration increases, the venous return increases, leading to increased cardiac output.Much research has focused on estimating respiratory rate from the photoplethysmogram, as well as more detailed respiratory measurements such as inspiratory time.
Biflaviolin synthase Summary Biflaviolin_synthase Biflaviolin synthase (EC 1.14.21.7, CYP158A2, CYP 158A2, cytochrome P450 158A2) is an enzyme with systematic name flaviolin,NADPH:oxygen oxidoreductase. This enzyme catalyses the following chemical reaction (1) 2 flaviolin + NADPH + H+ + O2 ⇌ {\displaystyle \rightleftharpoons } 3,3'-biflaviolin + NADP+ + 2 H2O (2) 2 flaviolin + NADPH + H+ + O2 ⇌ {\displaystyle \rightleftharpoons } 3,8'-biflaviolin + NADP+ + 2 H2OThis cytochrome P450 enzyme, from the soil-dwelling bacterium Streptomyces coelicolor A3(2), catalyses a phenol oxidation C-C coupling reaction.
Sacred art Geometry Sacred_art > Islamic art > Geometry The decorative features used use a variety of symmetries that are now recognized as belonging to separate mathematical groups, yet the patterns’ delicacy and elegance are unmatched in contemporary mathematical thought. Although it was once customary in Islam to use geometric shapes, these designs are works of architecture. Since the eighth century, Muslim calligraphers and geometric pattern designers have decorated mosques, castles and manuscripts.
Zodiacal light Other planets Zodiacal_light > Other planets Other planets, like Venus or Mercury, have shown to have rings of interplanetary dust in their orbital spaces.
File deletion Sensitive data File_deletion > Sensitive data The common problem with sensitive data is that deleted files are not really erased and so may be recovered by interested parties. Most file systems only remove the link to data. But even overwriting parts of the disk with something else or formatting it may not guarantee that the sensitive data is completely unrecoverable.
Braak staging Stage 1 Braak_staging > Parkinson's disease > Braak's theory > Stage 1 The disease begins in structures of the lower brainstem and the olfactory system. In particular, the dorsal motor nucleus of the vagus nerve in the medulla oblongata and anterior olfactory nucleus are affected. Lewy neurites, thread-like alpha-synuclein aggregates, are more prevalent than globular Lewy bodies in this stage.
Carcinogenesis Genetic and epigenetic Cancer_induction > Causes > Genetic and epigenetic There is a diverse classification scheme for the various genomic changes that may contribute to the generation of cancer cells. Many of these changes are mutations, or changes in the nucleotide sequence of genomic DNA. There are also many epigenetic changes that alter whether genes are expressed or not expressed. Aneuploidy, the presence of an abnormal number of chromosomes, is one genomic change that is not a mutation, and may involve either gain or loss of one or more chromosomes through errors in mitosis.
Complex Number Characterization as a topological field Complex_field > Properties > Characterization as a topological field {\displaystyle \mathbb {C} .} Moreover, C {\displaystyle \mathbb {C} } has a nontrivial involutive automorphism x ↦ x* (namely the complex conjugation), such that x x* is in P for any nonzero x in C . {\displaystyle \mathbb {C} .}
Hash browns Etymology Hash_browns > Etymology The word hash is derived from the French word "hacher", which means to hack or chop. This means hashed browned potatoes literally translates to "chopped and fried potatoes".
Liver protein synthesis Disease Colic_impression > Clinical significance > Disease Factors contributing to the development of alcoholic liver diseases are not only the quantity and frequency of alcohol consumption, but can also include gender, genetics, and liver insult. Liver damage can also be caused by drugs, particularly paracetamol and drugs used to treat cancer. A rupture of the liver can be caused by a liver shot used in combat sports.
P.I.P.S. Summary P.I.P.S. P.I.P.S. is a term (recursive acronym) for Symbian software libraries, and means "P.I.P.S. Is POSIX on Symbian OS". It is intended to help C language programmers in migration of desktop and server middleware, applications to Symbian OS based mobile smartphone devices.
Generalized gradient approximation Overview of method Density-functional_theory > Overview of method In the context of computational materials science, ab initio (from first principles) DFT calculations allow the prediction and calculation of material behavior on the basis of quantum mechanical considerations, without requiring higher-order parameters such as fundamental material properties. In contemporary DFT techniques the electronic structure is evaluated using a potential acting on the system's electrons. This DFT potential is constructed as the sum of external potentials Vext, which is determined solely by the structure and the elemental composition of the system, and an effective potential Veff, which represents interelectronic interactions. Thus, a problem for a representative supercell of a material with n electrons can be studied as a set of n one-electron Schrödinger-like equations, which are also known as Kohn–Sham equations.
Unit fractions Probability and statistics Unit_fractions > Applications > Probability and statistics In a uniform distribution on a discrete space, all probabilities are equal unit fractions. Due to the principle of indifference, probabilities of this form arise frequently in statistical calculations.Unequal probabilities related to unit fractions arise in Zipf's law. This states that, for many observed phenomena involving the selection of items from an ordered sequence, the probability that the n {\displaystyle n} th item is selected is proportional to the unit fraction 1 / n {\displaystyle 1/n} .
Discrete choice Summary Discrete_choice Discrete choice models statistically relate the choice made by each person to the attributes of the person and the attributes of the alternatives available to the person. For example, the choice of which car a person buys is statistically related to the person's income and age as well as to price, fuel efficiency, size, and other attributes of each available car. The models estimate the probability that a person chooses a particular alternative.
Johannes Kepler Astronomia Nova Johannes_Kepler > Astronomy > Astronomia Nova The extended line of research that culminated in Astronomia Nova (A New Astronomy)—including the first two laws of planetary motion—began with the analysis, under Tycho's direction, of the orbit of Mars. In this work Kepler introduced the revolutionary concept of planetary orbit, a path of a planet in space resulting from the action of physical causes, distinct from previously held notion of planetary orb (a spherical shell to which planet is attached). As a result of this breakthrough astronomical phenomena came to be seen as being governed by physical laws. Kepler calculated and recalculated various approximations of Mars's orbit using an equant (the mathematical tool that Copernicus had eliminated with his system), eventually creating a model that generally agreed with Tycho's observations to within two arcminutes (the average measurement error).
Lisinopril Mechanism of action Lisinopril > Pharmacology > Mechanism of action Lisinopril is an ACE inhibitor, meaning it blocks the actions of angiotensin-converting enzyme (ACE) in the renin–angiotensin–aldosterone system (RAAS), preventing angiotensin I from being converted to angiotensin II. Angiotensin II is a potent direct vasoconstrictor and a stimulator of aldosterone release. Reduction in the amount of angiotensin II results in relaxation of the arterioles.
Normable topology Definition Normable_topology > Definition Positive definiteness/positiveness/Point-separating: for all x ∈ X , {\displaystyle x\in X,} if p ( x ) = 0 {\displaystyle p(x)=0} then x = 0. {\displaystyle x=0.} Because property (2.)
History of electric power transmission Transformers and alternating current History_of_electric_power_transmission > Transformers and alternating current The three had discovered that all former coreless or open-core devices were incapable of regulating voltage, and were therefore impractical. Their joint patent described two versions of a design with no poles: the "closed-core transformer" and the "shell-core transformer". Ottó Bláthy suggested the use of closed-cores, Károly Zipernowsky the use of shunt connections, and Miksa Déri performed the experiments.
Prion diseases Role in neurodegenerative disease Prion_diseases > In other diseases > Role in neurodegenerative disease The misfolding of TDP-43 is largely directed by its prion-like domain. This domain is inherently prone to misfolding, while pathological mutations in TDP-43 have been found to increase this propensity to misfold, explaining the presence of these mutations in familial cases of ALS/MND. As in yeast, the prion-like domain of TDP-43 has been shown to be both necessary and sufficient for protein misfolding and aggregation.Similarly, pathogenic mutations have been identified in the prion-like domains of heterogeneous nuclear riboproteins hnRNPA2B1 and hnRNPA1 in familial cases of muscle, brain, bone and motor neuron degeneration. The wild-type form of all of these proteins show a tendency to self-assemble into amyloid fibrils, while the pathogenic mutations exacerbate this behaviour and lead to excess accumulation.
MiR-324-5p Future research and potential in medicine MiR-324-5p > Future research and potential in medicine miRNA-324-5p is a relatively new and understudied microRNA. It is an important regulator in several diseases, and its effects span across the body from neuronal dysregulation in seizure to hepatocellular carcinoma and cardiac disease. Because microRNAs have numerous targets, they are capable of regulating multiple pathways and circuits, an ability that may be useful in the treatment of complex disorders like epilepsy in which many subsystems are dysregulated.
Doppler optical coherence tomography Principles of Doppler OCT Doppler_optical_coherence_tomography > Principles of Doppler OCT Light hits the moving particles and is backscattered from the sample. Then the light interferes with the light in the reference beam, causing a Doppler frequency shift F D {\displaystyle F_{D}} in the interference fringe: F D ( v ) = ⋅ ( v ) ( k o − k i ) ( 1 ) {\displaystyle F_{D}\left(v\right)=\left\cdot (v)(k_{o}-k_{i})\qquad \quad (1)} where k i {\displaystyle k_{i}} and k o {\displaystyle k_{o}} are wave vectors of incident and out scattered light, and v is the velocity of the moving particle the instrument is detecting. Doppler OCT measures the light backscattered from the sample medium.
Magnetite Human brain Magnetite > Biological occurrences > Human brain Research suggests that beta-amyloid plaques and tau proteins associated with neurodegenerative disease frequently occur after oxidative stress and the build-up of iron.Some researchers also suggest that humans possess a magnetic sense, proposing that this could allow certain people to use magnetoreception for navigation. The role of magnetite in the brain is still not well understood, and there has been a general lag in applying more modern, interdisciplinary techniques to the study of biomagnetism.Electron microscope scans of human brain-tissue samples are able to differentiate between magnetite produced by the body's own cells and magnetite absorbed from airborne pollution, the natural forms being jagged and crystalline, while magnetite pollution occurs as rounded nanoparticles. Potentially a human health hazard, airborne magnetite is a result of pollution (specifically combustion).
Pulse transformer Resonant transformer Pulse_transformer > Power transformer > Resonant transformer They are also used in radio transmitters. Resonant transformers are also used in electronic ballasts for gas discharge lamps, and high voltage power supplies. They are also used in some types of switching power supplies.
Hepatic fibrosis Decompensated cirrhosis Hepatic_fibrosis > Treatment > Decompensated cirrhosis People with decompensated cirrhosis generally require admission to a hospital, with close monitoring of the fluid balance, mental status, and emphasis on adequate nutrition and medical treatment – often with diuretics, antibiotics, laxatives or enemas, thiamine and occasionally steroids, acetylcysteine and pentoxifylline. Administration of saline is avoided, as it would add to the already high total body sodium content that typically occurs in cirrhosis. Life expectancy without liver transplant is low, at most three years.
Harvard Project Physics Summary Harvard_Project_Physics Harvard Project Physics, also called Project Physics, was a national curriculum development project to create a secondary school physics education program in the United States during the Cold War era.
Bloom filters Algorithm description Bloom_filters > Algorithm description Since the simple algorithm provides no way to determine whether any other elements have been added that affect the bits for the element to be removed, clearing any of the bits would introduce the possibility of false negatives. One-time removal of an element from a Bloom filter can be simulated by having a second Bloom filter that contains items that have been removed. However, false positives in the second filter become false negatives in the composite filter, which may be undesirable.
Colorectal polyp Follow-up Colonic_polyp > Follow-up By United States guidelines, the following follow-up is recommended:
Comparison of webmail providers Secure delivery Comparison_of_webmail_providers > Digital rights > Secure delivery Features to reduce the risk of third-party tracking and interception of the email content; measures to increase the deliverability of correct outbound messages.
Pulmonary capillary hemangiomatosis Differential diagnosis Pulmonary_capillary_hemangiomatosis > Diagnosis > Differential diagnosis Pulmonary veno-occlusive disease
Induction plasma technology Summary Induction_plasma_technology Induction plasma, also called inductively coupled plasma, is a type of high temperature plasma generated by electromagnetic induction, usually coupled with argon gas. The magnetic field induces an electric current within the gas which creates the plasma. The plasma can reach temperatures up to 10,000 Kelvin. Inductive plasma technology is used in fields such as powder spheroidisation and nano-material synthesis. The technology is applied via an Induction plasma torch, which consists of three basic elements: the induction coil, a confinement chamber, and a torch head, or gas distributor. The main benefit of this technology is the elimination of electrodes, which can deteriorate and introduce contamination.
Gluing (topology) Quotient map Quotient_space_(topology) > Quotient map Every quotient map is continuous but not every continuous map is a quotient map. Saturated sets A subset S {\displaystyle S} of X {\displaystyle X} is called saturated (with respect to f {\displaystyle f} ) if it is of the form S = f − 1 ( T ) {\displaystyle S=f^{-1}(T)} for some set T , {\displaystyle T,} which is true if and only if f − 1 ( f ( S ) ) = S . {\displaystyle f^{-1}(f(S))=S.}
Space travel using constant acceleration In fiction Space_travel_using_constant_acceleration > In fiction The spacecraft of George O. Smith's Venus Equilateral stories are all constant acceleration ships. Normal acceleration is 1 g, but in "The External Triangle" it is mentioned that accelerations of up to 5 g are possible if the crew is drugged with gravanol to counteract the effects of the g-load. "Sky Lift" is a science fiction short story by Robert A. Heinlein, first published 1953. In the story, a torchship pilot lights out from Earth orbit to Pluto on a mission to deliver a cure to a plague ravaging a research station.Tau Zero, a hard science fiction novel by Poul Anderson, has a spaceship using a constant acceleration drive.
Newtonian theory Work and energy Classical_billiard_balls > Description of the theory > Work and energy If the work done in moving the particle from r1 to r2 is the same no matter what path is taken, the force is said to be conservative. Gravity is a conservative force, as is the force due to an idealized spring, as given by Hooke's law. The force due to friction is non-conservative.
Perron–Frobenius theorem Counterexamples Perron–Frobenius_theorem > Counterexamples The matrices L = ( 1 0 0 1 0 0 1 1 1 ) {\displaystyle \left({\begin{smallmatrix}1&0&0\\1&0&0\\1&1&1\end{smallmatrix}}\right)} , P = ( 1 0 0 1 0 0 − 1 1 1 ) {\displaystyle \left({\begin{smallmatrix}1&0&0\\1&0&0\\\!\!\!-1&1&1\end{smallmatrix}}\right)} , T = ( 0 1 1 1 0 1 1 1 0 ) {\displaystyle \left({\begin{smallmatrix}0&1&1\\1&0&1\\1&1&0\end{smallmatrix}}\right)} , M = ( 0 1 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 1 0 0 ) {\displaystyle \left({\begin{smallmatrix}0&1&0&0&0\\1&0&0&0&0\\0&0&0&1&0\\0&0&0&0&1\\0&0&1&0&0\end{smallmatrix}}\right)} provide simple examples of what can go wrong if the necessary conditions are not met. It is easily seen that the Perron and peripheral projections of L are both equal to P, thus when the original matrix is reducible the projections may lose non-negativity and there is no chance of expressing them as limits of its powers. The matrix T is an example of a primitive matrix with zero diagonal. If the diagonal of an irreducible non-negative square matrix is non-zero then the matrix must be primitive but this example demonstrates that the converse is false.
Lenz's Law Example Lenz's_Law > Definition > Example Magnetic fields from strong magnets can create counter-rotating currents in a copper or aluminium pipe. This is shown by dropping the magnet through the pipe. The descent of the magnet inside the pipe is observably slower than when dropped outside the pipe. When a voltage is generated by a change in magnetic flux according to Faraday's law, the polarity of the induced voltage is such that it produces a current whose magnetic field opposes the change which produces it.
Precancerous condition Pathophysiology Precancerous_condition > Pathophysiology The pathophysiology of precancerous lesions is thought to be similar to that of cancer, and also varies depending on the disease site and type of lesion. It is thought that cancer is always preceded by a clinically silent premalignant phase during which many oncogenic genetic and epigenetic alterations accumulate before it is truly malignant. The duration of this premalignant phase can vary from cancer to cancer, disease site to site and from individual to individual. Increasing evidence suggests that the evasion of the immune system occurs in premalignant lesions, and that the nature of the first immune response to these lesions may determine if they progress to cancer or regress to normal tissue.
T-matrix method Calculation of the T-matrix T-matrix_method > Calculation of the T-matrix Improvement of traditional T-matrix includes Invariant-imbedding T-matrix Method (IITM) by B. R. Johnson. The numerical code of IITM is developed by Lei Bi, based on Mishchenko's EBCM code. It is more powerful than EBCM as it is more efficient and increases the upper limit of particle size during the computation. == References ==
Bcache Summary Bcache bcache (abbreviated from block cache) is a cache in the Linux kernel's block layer, which is used for accessing secondary storage devices. It allows one or more fast storage devices, such as flash-based solid-state drives (SSDs), to act as a cache for one or more slower storage devices, such as hard disk drives (HDDs); this effectively creates hybrid volumes and provides performance improvements. Designed around the nature and performance characteristics of SSDs, bcache also minimizes write amplification by avoiding random writes and turning them into sequential writes instead.
Coase theorem The theorem Coase_theorem > The theorem Furthermore, it did not matter to whom the property rights were granted. His reasoning was that the station able to reap the higher economic gain from broadcasting would have an incentive to pay the other station not to interfere. In the absence of transaction costs, both stations would strike a mutually advantageous deal.
Agent-based model in biology Bacteria aggregation leading to biofilm formation Agent-based_model_in_biology > Cell-based modeling > Bacteria aggregation leading to biofilm formation The agent-based model suggests that if metabolic pathways can be switched without cost the faster the switching the better. However, where faster switching incurs a higher cost, there is a strategy with optimal response time for any frequency of environmental fluctuations. This suggests that different types of denitrifying strategies win in different biological environments.
Shear joint Calculating the torque Bolted_joint > Calculating the torque This friction can be affected by the application of a lubricant or any plating (e.g. cadmium or zinc) applied to the threads, and the fastener's standard defines whether the torque value is for dry or lubricated threading, as lubrication can reduce the torque value by 15% to 25%; lubricating a fastener designed to be torqued dry could over-tighten it, which may damage threading or stretch the fastener beyond its elastic limit, thereby reducing its clamping ability. Either the bolt head or the nut can be torqued. If one has a larger bearing area or coefficient of friction it will require more torque to provide the same target preload.
Kepler-13 Stellar system Kepler-13 > Stellar system The multiple nature of the system was discovered in 1904 by Robert Grant Aitken at Lick Observatory. He measured a separation between the A and B components of approximately one arc second and position angle of 281.3° with the 36" James Lick telescope. The position of the two visual components of the system relative to each other has remained constant since 1904. Radial velocity measurements taken with the SOPHIE échelle spectrograph at the Haute-Provence Observatory revealed an additional companion orbiting Kepler-13B. This companion has a mass of between 0.4 and 1 times that of the Sun and orbits with a period of 65.831 days with an eccentricity of 0.52
Ancestral reconstruction Bayesian inference Ancestral_reconstruction > Methods and algorithms > Bayesian inference P ( D \| S , θ ) {\displaystyle P(D\|S,\theta )} is the likelihood of the observed data which can be computed by Felsenstein's pruning algorithm as given above. P ( S \| θ ) {\displaystyle P(S\|\theta )} is the prior probability of the ancestral states for a given model and tree. Finally, P ( D \| θ ) {\displaystyle P(D\|\theta )} is the probability of the data for a given model and tree, integrated over all possible ancestral states.
LogP machine Summary LogP_machine The machine is described by the four parameters: L {\displaystyle L} , the latency of the communication medium. o {\displaystyle o} , the overhead of sending and receiving a message. g {\displaystyle g} , the gap required between two send/receive operations.

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