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Political knowledge Benjamin Constant Political_knowledge > History > European Enlightenment > Benjamin Constant Moreover, Constant believed that, in the modern world, commerce was superior to war. He attacked Napoleon's martial appetite, on the grounds that it was illiberal and no longer suited to modern commercial social organization. Ancient Liberty tended to be warlike, whereas a state organized on the principles of Modern Liberty would be at peace with all peaceful nations.
Alternative splicing Adaptive significance Alternatively_spliced > Adaptive significance A single point mutation may cause a given exon to be occasionally excluded or included from a transcript during splicing, allowing production of a new protein isoform without loss of the original protein. Studies have identified intrinsically disordered regions (see Intrinsically unstructured proteins) as enriched in the non-constitutive exons suggesting that protein isoforms may display functional diversity due to the alteration of functional modules within these regions. Such functional diversity achieved by isoforms is reflected by their expression patterns and can be predicted by machine learning approaches.
Circular arc Radius Circular_path > Radius Using the intersecting chords theorem (also known as power of a point or secant tangent theorem) it is possible to calculate the radius r of a circle given the height H and the width W of an arc: Consider the chord with the same endpoints as the arc. Its perpendicular bisector is another chord, which is a diameter of the circle. The length of the first chord is W, and it is divided by the bisector into two equal halves, each with length W/2. The total length of the diameter is 2r, and it is divided into two parts by the first chord.
Algebras over a field Associative algebra Unital_algebra > Kinds of algebras and examples > Associative algebra Examples of associative algebras include the algebra of all n-by-n matrices over a field (or commutative ring) K. Here the multiplication is ordinary matrix multiplication. group algebras, where a group serves as a basis of the vector space and algebra multiplication extends group multiplication. the commutative algebra K of all polynomials over K (see polynomial ring). algebras of functions, such as the R-algebra of all real-valued continuous functions defined on the interval , or the C-algebra of all holomorphic functions defined on some fixed open set in the complex plane.
Nerve tract Projection fibers Nerve_tract > Types > Projection fibers Projection tracts connect the cerebral cortex with the corpus striatum, diencephalon, brainstem and the spinal cord. The corticospinal tract for example, carries motor signals from the cerebrum to the spinal cord. Other projection tracts carry signals upward to the cerebral cortex. Superior to the brainstem, such tracts form a broad, dense sheet called the internal capsule between the thalamus and basal nuclei, then radiate in a diverging, fanlike array to specific areas of the cortex.
Phloretin hydrolase Summary Phloretin_hydrolase In enzymology, a phloretin hydrolase (EC 3.7.1.4) is an enzyme that catalyzes the chemical reaction phloretin + H2O ⇌ {\displaystyle \rightleftharpoons } phloretate + phloroglucinolThus, the two substrates of this enzyme are phloretin and H2O, whereas its two products are phloretate and phloroglucinol. This enzyme belongs to the family of hydrolases, specifically those acting on carbon–carbon bonds in ketonic substances. The systematic name of this enzyme class is 2',4,4',6'-tetrahydroxydehydrochalcone 1,3,5-trihydroxybenzenehydrolase. This enzyme is also called lactase-phlorizin hydrolase.
Crash simulation Analysis Crash_simulation > Analysis The Visual Crash Studio uses Macro Element Methodology. In comparison with FEM it has some modeling and boundary condition limitations but its application does not require advanced computers and the calculation time is incomparably smaller. Two presented methods complement each other. Macro Element Method is useful at early stage of the structure design process while Finite Element Method performs well at its final stages.
Least squares fitting Summary Least-squares_analysis The following discussion is mostly presented in terms of linear functions but the use of least squares is valid and practical for more general families of functions. Also, by iteratively applying local quadratic approximation to the likelihood (through the Fisher information), the least-squares method may be used to fit a generalized linear model. The least-squares method was officially discovered and published by Adrien-Marie Legendre (1805), though it is usually also co-credited to Carl Friedrich Gauss (1809), who contributed significant theoretical advances to the method and may have also used it in his earlier work (1795).
Georg Nees Modern generative graphic design Georg_Nees > Reception > Modern generative graphic design The current generation of designers uses as professional title for example "generative design" and operates under the concept of generative Design, data driven art or computational design. Nees also makes it one of the progenitors of today's generative design for art, advertising and animation – based on his Ph.D. thesis Generative Computergraphik and the book Generative Computergraphik in 1969.
Genetic exchange Summary Genetic_exchange Gene flow is an important mechanism for transferring genetic diversity among populations. Migrants change the distribution of genetic diversity among populations, by modifying allele frequencies (the proportion of members carrying a particular variant of a gene). High rates of gene flow can reduce the genetic differentiation between the two groups, increasing homogeneity.
Metre per second squared Example Metre_per_second_squared > Example An object experiences a constant acceleration of one metre per second squared (1 m/s2) from a state of rest, then it achieves the speed of 5 m/s after 5 seconds and 10 m/s after 10 seconds. The average acceleration a can be calculated by dividing the speed v (m/s) by the time t (s), so the average acceleration in the first example would be calculated: a = Δ v Δ t = 5 m/s 5 s = 1 (m/s)/s = 1 m/s 2 {\displaystyle a={\frac {\Delta v}{\Delta t}}={\frac {5{\text{ m/s}}}{5{\text{ s}}}}=1{\text{ (m/s)/s}}=1{\text{ m/s}}^{2}} .
Lagrangian relaxation Summary Lagrangian_relaxation In the field of mathematical optimization, Lagrangian relaxation is a relaxation method which approximates a difficult problem of constrained optimization by a simpler problem. A solution to the relaxed problem is an approximate solution to the original problem, and provides useful information. The method penalizes violations of inequality constraints using a Lagrange multiplier, which imposes a cost on violations. These added costs are used instead of the strict inequality constraints in the optimization. In practice, this relaxed problem can often be solved more easily than the original problem. The problem of maximizing the Lagrangian function of the dual variables (the Lagrangian multipliers) is the Lagrangian dual problem.
COVID-19 misinformation Cruise ships as safe havens CPC_virus > Disease spread > Cruise ships as safe havens In March 2020, the Miami New Times reported that managers at Norwegian Cruise Line had prepared a set of responses intended to convince wary customers to book cruises, including "blatantly false" claims that COVID-19 "can only survive in cold temperatures, so the Caribbean is a fantastic choice for your next cruise", that "Scientists and medical professionals have confirmed that the warm weather of the spring will be the end of the Coronavirus ", and that the virus "cannot live in the amazingly warm and tropical temperatures that your cruise will be sailing to".Flu is seasonal (becoming less frequent in the summer) in some countries, but not in others. While it is possible that COVID-19 will also show some seasonality, this has not yet been determined. When COVID-19 spread along international air travel routes, it did not bypass tropical locations.
Species selection Species and higher levels Unit_of_selection > Selection at each level > Species and higher levels For evolution to be driven by species selection, differential success must be the result of selection upon species-intrinsic properties, rather than for properties of genes, cells, individuals, or populations within species. Such properties include, for example, population structure, their propensity to speciate, extinction rates, and geological persistence. While the fossil record shows differential persistence of species, examples of species-intrinsic properties subject to natural selection have been much harder to document.
String substitution Summary String_operation In computer science, in the area of formal language theory, frequent use is made of a variety of string functions; however, the notation used is different from that used for computer programming, and some commonly used functions in the theoretical realm are rarely used when programming. This article defines some of these basic terms.
Kappa effect Constant velocity expectation Kappa_effect > Theories based in velocity expectation > Constant velocity expectation According to the constant velocity hypothesis proposed by Jones and Huang (1982), the brain incorporates a prior expectation of speed when judging spatiotemporal intervals. Specifically, the brain expects temporal intervals that would produce constant velocity (i.e., uniform motion) movement. Thus, the kappa effect occurs when we apply our knowledge of motion to stimulus sequences, which sometimes leads us to make mistakes. Evidence for the role of a uniform motion expectation in temporal perception comes from a study in which participants observed eight white dots that successively appeared in one direction in a horizontal alignment along a straight line.
Mode (user interface) Assessment Mode_(user_interface) > Assessment Modes are intended to grab the user's full attention and to cause them to acknowledge the content present in them, in particular when critical confirmation from the user is required. This latter use is criticised as ineffective for its intended use (protection against errors in destructive actions) due to habituation. Actually making the action reversible (providing an "undo" option) is recommended instead. Though modes can be successful in particular usages to restrict dangerous or undesired operations, especially when the mode is actively maintained by a user as a quasimode.
Best fit line Simple and multiple linear regression Linear_trend > Extensions > Simple and multiple linear regression The very simplest case of a single scalar predictor variable x and a single scalar response variable y is known as simple linear regression. The extension to multiple and/or vector-valued predictor variables (denoted with a capital X) is known as multiple linear regression, also known as multivariable linear regression (not to be confused with multivariate linear regression). Multiple linear regression is a generalization of simple linear regression to the case of more than one independent variable, and a special case of general linear models, restricted to one dependent variable. The basic model for multiple linear regression is Y i = β 0 + β 1 X i 1 + β 2 X i 2 + … + β p X i p + ϵ i {\displaystyle Y_{i}=\beta _{0}+\beta _{1}X_{i1}+\beta _{2}X_{i2}+\ldots +\beta _{p}X_{ip}+\epsilon _{i}} for each observation i = 1, ... , n. In the formula above we consider n observations of one dependent variable and p independent variables.
Test theories of special relativity Summary Test_theories_of_special_relativity Test theories of special relativity give a mathematical framework for analyzing results of experiments to verify special relativity. An experiment to test the theory of relativity cannot assume the theory is true, and therefore needs some other framework of assumptions that are wider than those of relativity. For example, a test theory may have a different postulate about light concerning one-way speed of light vs. two-way speed of light, it may have a preferred frame of reference, and may violate Lorentz invariance in many different ways. Test theories predicting different experimental results from Einstein's special relativity, are Robertson's test theory (1949), and the Mansouri–Sexl theory (1977) which is equivalent to Robertson's theory. Another, more extensive model is the Standard-Model Extension, which also includes the standard model and general relativity.
Barrelled space Characterizations of barreled spaces Barrelled_space > Characterizations of barreled spaces For any F-space Y . {\displaystyle Y.} every pointwise bounded subset of L ( X ; Y ) {\displaystyle L(X;Y)} is equicontinuous.An F-space is a complete metrizable TVS.Every closed linear operator from X {\displaystyle X} into a complete metrizable TVS is continuous.A linear map F: X → Y {\displaystyle F:X\to Y} is called closed if its graph is a closed subset of X × Y .
Triple resonance experiments Background Triple_resonance_experiments > Background This limitation is due to the need to assign NMR signals from the large number of nuclei in the protein – in larger protein, the greater number of nuclei results in overcrowding of resonances, and the increasing size of the protein also broadens the signals, making resonance assignment difficult. These problems may be alleviated by using heteronuclear NMR spectroscopy which allows the proton spectrum to be edited with respect to the 15N and 13C chemical shifts, and also reduces the overlap of resonances by increasing the number of dimensions of the spectrum. In 1990, Ad Bax and coworkers developed the triple resonance technology and experiments on proteins isotopically labelled with 15N and 13C, with the result that the spectra are dramatically simplified, greatly facilitating the process of resonance assignment, and increasing the size of the protein that may be determined by NMR.
Induction coils Interrupter Ruhmkorff_coil > Construction and function > Interrupter Also, the collapsed field no longer attracts the armature, so the spring force accelerates the armature toward its initial position. A short time later the contacts reconnect, and the current starts building the magnetic field again.
Determination of equilibrium constants Chemical constraints Determination_of_equilibrium_constants > Computational methods > Model selection > Chemical constraints When determining the stability constants of metal-ligand complexes, it is common practice to fix ligand protonation constants at values that have been determined using data obtained from metal-free solutions. Hydrolysis constants of metal ions are usually fixed at values which were obtained using ligand-free solutions. When determining the stability constants for ternary complexes, MpAqBr it is common practice the fix the values for the corresponding binary complexes Mp′Aq′ and Mp′′Bq′′, at values which have been determined in separate experiments. Use of such constraints reduces the number of parameters to be determined, but may result in the calculated errors on refined stability constant values being under-estimated.
DNA molecule History Phosphodiester_backbone > History In 1933, while studying virgin sea urchin eggs, Jean Brachet suggested that DNA is found in the cell nucleus and that RNA is present exclusively in the cytoplasm. At the time, "yeast nucleic acid" (RNA) was thought to occur only in plants, while "thymus nucleic acid" (DNA) only in animals. The latter was thought to be a tetramer, with the function of buffering cellular pH.In 1937, William Astbury produced the first X-ray diffraction patterns that showed that DNA had a regular structure.In 1943, Oswald Avery, along with co-workers Colin MacLeod and Maclyn McCarty, identified DNA as the transforming principle, supporting Griffith's suggestion (Avery–MacLeod–McCarty experiment).
Convolution kernel Fast convolution algorithms Convolution_operation > Discrete convolution > Fast convolution algorithms Convolutions of the type defined above are then efficiently implemented using that technique in conjunction with zero-extension and/or discarding portions of the output. Other fast convolution algorithms, such as the Schönhage–Strassen algorithm or the Mersenne transform, use fast Fourier transforms in other rings. The Winograd method is used as an alternative to the FFT.
Foreach loop R Foreach_loop > Language support > R As for ... in is the only kind of for loop in R, the equivalent to the "counter" loop found in other languages is...
Quartic interaction The Lagrangian for a complex scalar field Quartic_interaction > The Lagrangian for a complex scalar field In all of the models above, the coupling constant λ {\displaystyle \lambda } must be positive, since otherwise the potential would be unbounded below, and there would be no stable vacuum. Also, the Feynman path integral discussed below would be ill-defined. In 4 dimensions, ϕ 4 {\displaystyle \phi ^{4}} theories have a Landau pole.
Cryptogenic organizing pneumonitis Imaging Cryptogenic_organizing_pneumonia > Diagnosis > Imaging The chest x-ray is distinctive with features that appear similar to an extensive pneumonia, with both lungs showing widespread white patches. The white patches may seem to migrate from one area of the lung to another as the disease persists or progresses. Computed tomography (CT) may be used to confirm the diagnosis. Often the findings are typical enough to allow the doctor to make a diagnosis without ordering additional tests.
Max Planck Black-body radiation Max_Planck > Life and career > Black-body radiation In November 1900 Planck revised this first version, now relying on Boltzmann's statistical interpretation of the second law of thermodynamics as a way of gaining a more fundamental understanding of the principles behind his radiation law. Planck was deeply suspicious of the philosophical and physical implications of such an interpretation of Boltzmann's approach; thus his recourse to them was, as he later put it, "an act of despair ... I was ready to sacrifice any of my previous convictions about physics".The central assumption behind his new derivation, presented to the DPG on 14 December 1900, was the supposition, now known as the Planck postulate, that electromagnetic energy could be emitted only in quantized form, in other words, the energy could only be a multiple of an elementary unit: E = h ν {\displaystyle E=h\nu } where h is Planck's constant, also known as Planck's action quantum (introduced already in 1899), and ν is the frequency of the radiation. Note that the elementary units of energy discussed here are represented by hν and not simply by ν. Physicists now call these quanta photons, and a photon of frequency ν will have its own specific and unique energy.
Magic acid Reactions with alkanes Magic_acid > Uses > Reactions with alkanes This is evidence to suggest that in these reactions, methane is indeed a base, and can accept a proton from the acid medium to form CH+5. This ion is then deprotonated, explaining the hydrogen exchange, or loses a hydrogen molecule to form CH+3 – the carbonium ion. This species is quite reactive, and can yield several new carbocations, shown below.
Point groups in four dimensions Duoprismatic symmetry Point_groups_in_four_dimensions > Notation for groups > Duoprismatic symmetry It is isomorphic to the abstract group (4,4\|2,4). Other extended ,2,4], ], order 128, and are isomorphic to and . The 4–8 duoprism has this symmetry, as or .
Web proxies Web proxy servers Transparent_proxy > Implementations of proxies > Web proxy servers Web proxies forward HTTP requests. The request from the client is the same as a regular HTTP request except the full URL is passed, instead of just the path. This request is sent to the proxy server, the proxy makes the request specified and returns the response. Some web proxies allow the HTTP CONNECT method to set up forwarding of arbitrary data through the connection; a common policy is to only forward port 443 to allow HTTPS traffic. Examples of web proxy servers include Apache (with mod_proxy or Traffic Server), HAProxy, IIS configured as proxy (e.g., with Application Request Routing), Nginx, Privoxy, Squid, Varnish (reverse proxy only), WinGate, Ziproxy, Tinyproxy, RabbIT and Polipo. For clients, the problem of complex or multiple proxy-servers is solved by a client-server Proxy auto-config protocol (PAC file).
Collections Framework TreeMap Java_collections_framework > Map interfaces > Map interface implementations > AbstractMap class > TreeMap TreeMap, in contrast to HashMap and LinkedHashMap, uses a red–black tree. The keys are used as the values for the nodes in the tree, and the nodes point to the elements in the Map.
C2H3ClF2 Environmental effects 1-Chloro-1,1-difluoroethane > Environmental effects The concentration of HCFC-142b in the atmosphere grew to over 20 parts per trillion by year 2010. It has an ozone depletion potential (ODP) of 0.07. This is low compared to the ODP=1 of trichlorofluoromethane (CFC-11, R-11), which also grew about ten times more abundant in the atmosphere by year 1985 (prior to introduction of HFC-142b and the Montreal Protocol).
Schwarzschild's equation for radiative transfer Background Schwarzschild's_equation_for_radiative_transfer > Background A medium is in LTE when the fraction of molecules in an excited state is determined by the Boltzmann distribution. LTE exists when collisional excitation and collisional relaxation of any excited state occur much faster than absorption and emission. (LTE does not require the rates of absorption and emission to be equal.)
Cours d'Analyse Preliminaries Cours_d'Analyse > Preliminaries Cauchy originally defined the sinus versus (versine) as siv(θ) = 1 − cos(θ) and the cosinus versus (what is now also known as coversine) as cosiv(θ) = 1 − sin(θ). In the translation, however, the cosinus versus (and cosiv) are incorrectly associated with the versed cosine (what is now also known as vercosine) rather than the coversed sine. The notation limis introduced on page 12.
Lempel-Ziv-Markov algorithm Hash chains Lempel-Ziv-Markov_algorithm > Compression algorithm details > Dictionary search data structures > Hash chains The simplest approach, called "hash chains", is parameterized by a constant N which can be either 2, 3 or 4, which is typically chosen so that 28×N is greater than or equal to the dictionary size. It consists of creating, for each k less than or equal to N, a hash table indexed by tuples of k bytes, where each of the buckets contains the last position where the first k bytes hashed to the hash value associated with that hash table bucket. Chaining is achieved by an additional array which stores, for every dictionary position, the last seen previous position whose first N bytes hash to the same value of the first N bytes of the position in question. To find matches of length N or higher, a search is started using the N-sized hash table, and continued using the hash chain array; the search stop after a pre-defined number of hash chain nodes has been traversed, or when the hash chains "wraps around", indicating that the portion of the input that has been overwritten in the dictionary has been reached.
Handshake By geographic location Handshake > Modern customs > By geographic location The handshake may be followed by lightly touching one's heart with one's right hand. In Armenia, handshakes are the most common greetings between men, optionally followed by a kiss on the cheek if the two parties have a close relationship. Traditionally, a woman needs to wait for the man to present his hand for the handshake.
6-string guitar Bridge Six-string_guitar > Construction > Components > Body > Bridge The main purpose of the bridge on an acoustic guitar is to transfer the vibration from the strings to the soundboard, which vibrates the air inside of the guitar, thereby amplifying the sound produced by the strings. On all electric, acoustic and original guitars, the bridge holds the strings in place on the body. There are many varied bridge designs. There may be some mechanism for raising or lowering the bridge saddles to adjust the distance between the strings and the fretboard (action), or fine-tuning the intonation of the instrument.
Summability method Analytic continuation Abel_summation > Analytic continuation Several summation methods involve taking the value of an analytic continuation of a function.
Half-exponential function Summary Half-exponential_function In mathematics, a half-exponential function is a functional square root of an exponential function. That is, a function f {\displaystyle f} such that f {\displaystyle f} composed with itself results in an exponential function: for some constants a {\displaystyle a} and b {\displaystyle b} .
Average-case complexity Other results Average_case_complexity > Other results In 1990, Impagliazzo and Levin showed that if there is an efficient average-case algorithm for a distNP-complete problem under the uniform distribution, then there is an average-case algorithm for every problem in NP under any polynomial-time samplable distribution. Applying this theory to natural distributional problems remains an outstanding open question.In 1992, Ben-David et al. showed that if all languages in distNP have good-on-average decision algorithms, they also have good-on-average search algorithms. Further, they show that this conclusion holds under a weaker assumption: if every language in NP is easy on average for decision algorithms with respect to the uniform distribution, then it is also easy on average for search algorithms with respect to the uniform distribution. Thus, cryptographic one-way functions can exist only if there are distNP problems over the uniform distribution that are hard on average for decision algorithms.
Hydrodynamica Summary Hydrodynamica In doing so, Bernoulli explained the nature of hydrodynamic pressure and discovered the role of loss of vis viva in fluid flow, which would later be known as the Bernoulli principle. The book also discusses hydraulic machines and introduces the notion of work and efficiency of a machine. In the tenth chapter, Bernoulli discussed the first model of the kinetic theory of gases. Assuming that heat increases the velocity of the gas particles, he demonstrated that the pressure of air is proportional to kinetic energy of gas particles, thus making the temperature of gas proportional to this kinetic energy as well.
Gastric lipase Function Gastric_lipase > Function Acidic lipases make up 30% of lipid hydrolysis occurring during digestion in the human adult, with gastric lipase contributing the most of the two acidic lipases. In neonates, acidic lipases are much more important, providing up to 50% of total lipolytic activity. Gastric lipase hydrolyzes the ester bonds of triglycerides in the stomach.
Epidemiology of tuberculosis History Giant_multinucleated_cell > History Both strains of the tuberculosis bacteria share a common ancestor, which could have infected humans even before the Neolithic Revolution. Skeletal remains show some prehistoric humans (4000 BC) had TB, and researchers have found tubercular decay in the spines of Egyptian mummies dating from 3000 to 2400 BC. Genetic studies suggest the presence of TB in the Americas from about AD 100.Before the Industrial Revolution, folklore often associated tuberculosis with vampires.
Electronic feedback loop Positive and negative feedback Feedback_loop > Types > Positive and negative feedback The resulting change in engine torque, the feedback, combines with the torque exerted by the change of road grade to reduce the error in speed, minimising the changing slope. The terms "positive" and "negative" were first applied to feedback prior to WWII.
Neural computing Organization Neural_network_models > Models > Organization They can be 'fully connected', with every neuron in one layer connecting to every neuron in the next layer. They can be pooling, where a group of neurons in one layer connects to a single neuron in the next layer, thereby reducing the number of neurons in that layer. Neurons with only such connections form a directed acyclic graph and are known as feedforward networks. Alternatively, networks that allow connections between neurons in the same or previous layers are known as recurrent networks.
Timeline of special relativity and the speed of light 1900s Timeline_of_special_relativity_and_the_speed_of_light > 20th century > 1900s Also, Poincaré is the first to describe the relativistic velocity-addition formula – implicitly in his publication and explicitly in his letter to Lorentz. 1905 – Albert Einstein publishes his special theory of relativity, including the mass–energy equivalence that would be later written as E = mc2. 1906 – Alfred Bucherer introduces the name theory of relativity, based on Max Planck’s term relative theory.
Directive (programming) PL/SQL Directive_(programming) > Other languages > PL/SQL Oracle Corporation's PL/SQL procedural language includes a set of compiler directives, known as "pragmas".
Endemic pemphigus foliaceus Cause Endemic_pemphigus_foliaceus > Cause The National Institute of Arthritis and Musculoskeletal and Skin Diseases describes it like this: Normally, our immune system produces antibodies that attack viruses and harmful bacteria to keep us healthy. In people with pemphigus, however, the immune system mistakenly attacks the cells in the epidermis, or top layer of the skin, and the mucous membranes. The immune system produces antibodies against proteins in the skin known as desmogleins.
C2H5N3O2 Summary C2H5N3O2 The molecular formula C2H5N3O2 (molar mass: 103.08 g/mol, exact mass: 103.0382 u) may refer to: Biuret N-Nitroso-N-methylurea (NMU)
Venti Details Venti > Details The data structure used for the index is a hash table with fixed-sized buckets. Venti relies on the scores to be randomly distributed so buckets do not fill up. Since each lookup costs one disk seek time, an index usually consists of multiple hard drives with low access time.
Operant conditioning Schedules of reinforcement Operant_conditioning > Concepts and procedures > Modifying operant behavior: reinforcement and punishment > Schedules of reinforcement This schedule typically yields a very high, persistent rate of response. Continuous reinforcement: Reinforcement occurs after each response. Organisms typically respond as rapidly as they can, given the time taken to obtain and consume reinforcement, until they are satiated.
Lorentz boosts Coordinate transformation Lorentz_transformation > Physical formulation of Lorentz boosts > Coordinate transformation A "stationary" observer in frame F defines events with coordinates t, x, y, z. Another frame F′ moves with velocity v relative to F, and an observer in this "moving" frame F′ defines events using the coordinates t′, x′, y′, z′. The coordinate axes in each frame are parallel (the x and x′ axes are parallel, the y and y′ axes are parallel, and the z and z′ axes are parallel), remain mutually perpendicular, and relative motion is along the coincident xx′ axes. At t = t′ = 0, the origins of both coordinate systems are the same, (x, y, z) = (x′, y′, z′) = (0, 0, 0). In other words, the times and positions are coincident at this event.
Antigenic mimicry Autoimmunity Molecular_mimicry > Autoimmunity Autoimmunity can thus be defined simply as exceptions to the tolerance "rules." By doing this, an immune response is generated against self-tissue and cells. These mechanisms are known by many to be intrinsic. However, there are pathogenic mechanisms for the generation of autoimmune disease.
Virtual workplaces Summary Virtual_workplaces A virtual workplace is a work environment where employees can perform their duties remotely, using technology such as laptops, smartphones, and video conferencing tools. A virtual workplace is not located in any one physical space. It is usually a network of several workplaces technologically connected (via a private network or the Internet) without regard to geographic boundaries. Employees are thus able to interact in a collaborative working environment regardless of where they are located.
Queuing delay Router processing Queuing_delay > Router processing This term is most often used in reference to routers. When packets arrive at a router, they have to be processed and transmitted. A router can only process one packet at a time. If packets arrive faster than the router can process them (such as in a burst transmission) the router puts them into the queue (also called the buffer) until it can get around to transmitting them.
Thermal image Thermal energy Thermal_image > Thermal energy So if there is a cool area in the thermogram, that object will be absorbing the radiation emitted by the warm object. The ability of objects to emit is called emissivity, to absorb radiation is called absorptivity.
Dalton (unit) Summary Atomic_mass_constant The dalton or unified atomic mass unit (symbols: Da or u) is a non-SI unit of mass defined as 1/12 of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest. The atomic mass constant, denoted mu, is defined identically, giving mu = 1/12 m(12C) = 1 Da.This unit is commonly used in physics and chemistry to express the mass of atomic-scale objects, such as atoms, molecules, and elementary particles, both for discrete instances and multiple types of ensemble averages. For example, an atom of helium-4 has a mass of 4.0026 Da.
Hydrogen isotope biogeochemistry Plant leaf waxes Hydrogen_isotope_biogeochemistry > Applications > Paleo-reconstruction > Biomolecules > Plant leaf waxes Δ D e = ϵ e q + ϵ k + ( Δ D v − ϵ k ) ( e a e i ) {\displaystyle \Delta D_{e}=\epsilon _{eq}+\epsilon _{k}+(\Delta D_{v}-\epsilon _{k})({\frac {e_{a}}{e_{i}}})} The Péclet effect, which describes the opposing forces of advection and diffusion can be added to the model as P = E L C D {\displaystyle P={\frac {EL}{CD}}} where E is the transpiration rate, L is the length scale of transport, C is the concentration of water, and D is the diffusion coefficient. Δ D leaf = Δ D e ( 1 − e P ) P {\displaystyle \Delta D_{\text{leaf}}=\Delta D_{e}{\frac {(1-e^{P})}{P}}} While the role of rain water δD as the fundamental control on the final δD of lipids is well documented, the importance of fractionation effects from rain water to soil water and leaf water on εl/w is appreciated but remains poorly understood.Organic biomolecules are generally depleted relative to the δD of leaf water. However, differences between organisms, biosynthetic pathways, and biological roles of different molecules can lead to huge variability in fractionation; the diversity of lipid biomarkers spans a 600‰ range of δD values.
Domain theory Generalizations Domain_theory > Generalizations "Synthetic domain theory". CiteSeerX 10.1.1.55.903. {{cite journal}}: Cite journal requires \|journal= (help) Topological domain theory A continuity space is a generalization of metric spaces and posets that can be used to unify the notions of metric spaces and domains.
Progressive wave Differential wave equations Signal_propagation > Mathematical description > Differential wave equations (The symbol " ∂ {\displaystyle \partial } " is meant to signify that, in the derivative with respect to some variable, all other variables must be considered fixed.) This equation can be derived from the laws of physics that govern the diffusion of heat in solid media. For that reason, it is called the heat equation in mathematics, even though it applies to many other physical quantities besides temperatures.
Translational kinetic energy Kinetic energy of systems Translational_kinetic_energy > Kinetic energy for non-relativistic velocity > Kinetic energy of systems The kinetic energy of the system is the sum of the kinetic energies of the bodies it contains. A macroscopic body that is stationary (i.e. a reference frame has been chosen to correspond to the body's center of momentum) may have various kinds of internal energy at the molecular or atomic level, which may be regarded as kinetic energy, due to molecular translation, rotation, and vibration, electron translation and spin, and nuclear spin. These all contribute to the body's mass, as provided by the special theory of relativity. When discussing movements of a macroscopic body, the kinetic energy referred to is usually that of the macroscopic movement only. However, all internal energies of all types contribute to a body's mass, inertia, and total energy.
Distributed ledger technology law Issue of automation of smart contracts and 'Oracles' Distributed_ledger_technology_law > DLT and law issues > Issue of automation of smart contracts and 'Oracles' To facilitate the self-execution, a smart contract needs access to sources of event information through which the execution of its terms and conditions is assessed. "In the interest rate swap example, the distributed ledger must have access to assets of the parties in order to fulfil the parties' payment obligations, and it must have access to a provider of interest rate information." The solutions to the issue of access to assets vary and may be solved through locking and release of assets in smart contract as it is performed through use of cryptocurrency Ether on Ethereum blockchain or by introducing new mechanism of access to assets like 'cash states' proposed by Corda distributed ledger.
Electrolysis Decomposition potential Electrolysis > Overview > Decomposition potential Decomposition potential or decomposition voltage refers to the minimum voltage (difference in electrode potential) between anode and cathode of an electrolytic cell that is needed for electrolysis to occur.The voltage at which electrolysis is thermodynamically preferred is the difference of the electrode potentials as calculated using the Nernst equation. Applying additional voltage, referred to as overpotential, can increase the rate of reaction and is often needed above the thermodynamic value. It is especially necessary for electrolysis reactions involving gases, such as oxygen, hydrogen or chlorine.
Unitary theories of memory Overview Unitary_theories_of_memory > Background > Overview Working memory is the system that is responsible for the transient holding and processing of new and already stored information, an important process for reasoning, comprehension, learning and memory updating. Working memory is generally used synonymously with short term memory, but this depends on how the two forms of memory are defined. Working memory includes subsystems that store and manipulate visual images or verbal information, as well as a central executive that coordinates the subsystems. It includes visual representation of the possible moves, and awareness of the flow of information into and out of memory, all stored for a limited amount of time.
Polyuronide Examples Polyuronide > Examples Glucoronic acid Galactoronic acid
Methane functionalization Summary Methane_functionalization In a typical C-H activation mechanism, a transition metal catalyst coordinates to the C-H bond to cleave it, and convert it into a bond with a lower bond dissociation energy. By doing so, the product can be used in further downstream reactions, since it will usually have a new functional group attached to the carbon. It is also important to note the difference between the terms "activation" and "functionalization," since both terms are often used interchangeably, but should be held distinct from each other. Activation refers to the coordination of a metal center to the C-H bond, whereas functionalization occurs when the coordinated metal complex is further reacted with a group "X" to result in the functionalized product.
Stream data Usage Data_stream > Usage There are various areas where data streams are used: Fraud detection & scoring – raw data is used as source data for an anti-fraud algorithm (data analysis techniques for fraud detection). For example, timestamps, cookie occurrences or analysis of data points are used within the scoring system to detect fraud or to make sure that a message receiver is not a bot (so-called Non-Human Traffic). Artificial intelligence – raw data is treated like a train set and a test set during AI and machine learning algorithms building. Raw data is used for profiling and personalization to customize user profiles and divide them for segmentation, e.g., per gender or location (based on data point).
Geometric multiplicity Molecular orbitals Simple_eigenvalue > Applications > Molecular orbitals In quantum mechanics, and in particular in atomic and molecular physics, within the Hartree–Fock theory, the atomic and molecular orbitals can be defined by the eigenvectors of the Fock operator. The corresponding eigenvalues are interpreted as ionization potentials via Koopmans' theorem. In this case, the term eigenvector is used in a somewhat more general meaning, since the Fock operator is explicitly dependent on the orbitals and their eigenvalues.
Carbonyl α-substitution reactions Acidity of alpha-hydrogen atoms: enolate ion formation Carbonyl_Alpha-Substitution_Reactions > Acidity of alpha-hydrogen atoms: enolate ion formation Lithium diisopropylamide (LDA), which is easily prepared by reaction of the strong base butyllithium with diisopropylamine, is widely used in the laboratory as a base for preparing enolate ions from carbonyl compounds. Many types of carbonyl compounds, including aldehydes, ketones, esters, thioesters, acids, and amides, can be converted into enolate ions by reaction with LDA. Note that nitriles, too, are acidic and can be converted into enolate-like anions (referred to as nitrile anions).
L1-norm principal component analysis Code L1-norm_principal_component_analysis > Code MATLAB code for L1-PCA is available at MathWorks and other repositories. == References ==
Physics of roller coasters Energy Physics_of_roller_coasters > Energy Initially, the car is pulled to the top of the first hill and released, at which point it rolls freely along the track without any external mechanical assistance for the remainder of the ride. The purpose of the ascent of the first hill is to build up potential energy that will then be converted to kinetic energy as the ride progresses. The initial hill, or the lift hill, is the highest in the entire ride. As the train is pulled to the top, it gains potential energy, as explained by the equation for potential energy below: U g = m g h {\displaystyle U_{g}=mgh} where Ug is potential energy, m is mass, g is acceleration due to gravity and h is height above the ground.
Propagation constraint Summary Propagation_constraint An example of breaking referential integrity: if a table of employees includes a department number for 'Housewares' which is a foreign key to a table of departments and a user deletes that department from the department table then Housewares employees records would refer to a non-existent department number. Propagation constraints are methods used by relational database management systems (RDBMS) to solve this problem by ensuring that relationships between tables are preserved without error. In his database textbook, Beynon-Davies explains the three ways that RDBMS handle deletions of target and related tuples: Restricted Delete - the user cannot delete the target row until all rows that point to it (via foreign keys) have been deleted.
Power electronic DC/AC converters (inverters) Power_electronic > DC/AC converters (inverters) Similarly, current source inverters (CSIs) are distinct in that the controlled AC output is a current waveform. DC to AC power conversion is the result of power switching devices, which are commonly fully controllable semiconductor power switches. The output waveforms are therefore made up of discrete values, producing fast transitions rather than smooth ones.
Distributed operating system Three basic distributions Distributed_operating_system > Distributed computing models > Three basic distributions To better illustrate this point, examine three system architectures; centralized, decentralized, and distributed. In this examination, consider three structural aspects: organization, connection, and control. Organization describes a system's physical arrangement characteristics. Connection covers the communication pathways among nodes. Control manages the operation of the earlier two considerations.
Potentiometric titration Summary Potentiometric_titration Ecell depends on the concentration of the interested ions with which the indicator electrode is in contact. For example, the electrode reaction may be M n + + n e − ⟶ M {\displaystyle {\ce {M}}^{n+}+n\ {\ce {e- -> M}}} As the concentration of Mn+ changes, the Ecell changes correspondingly. Thus the potentiometric titration involve measurement of Ecell with the addition of titrant. Types of potentiometric titration include acid–base titration (total alkalinity and total acidity), redox titration (HI/HY and cerate), precipitation titration (halides), and complexometric titration (free EDTA and Antical #5).
Evolutionary divergence Summary Divergent_evolution Divergent evolution or divergent selection is the accumulation of differences between closely related populations within a species, sometimes leading to speciation. Divergent evolution is typically exhibited when two populations become separated by a geographic barrier (such as in allopatric or peripatric speciation) and experience different selective pressures that drive adaptations to their new environment. After many generations and continual evolution, the populations become less able to interbreed with one another. The American naturalist J. T. Gulick (1832–1923) was the first to use the term "divergent evolution", with its use becoming widespread in modern evolutionary literature.
Meta-circular evaluator From self-interpreter to abstract machine Meta-circular_evaluator > Self-interpreters > From self-interpreter to abstract machine The core evaluator has three clauses: It maps a variable (represented with a de Bruijn index) into the value in the current environment at this index. It maps a syntactic function into a semantic function. (Applying a semantic function to an argument reduces to evaluating the body of the corresponding syntactic function in its lexical environment, extended with the argument.)
Computer-supported cooperative work Affordance Computer_Supported_Cooperative_Work > Central concerns and concepts > Considerations for interaction design > Affordance As media platforms proliferate, so do the affordances offered that directly influence how users manage their self-presentation. According to researchers, the three most influential affordances on how users present themselves in an online domain include anonymity, persistence, and visibility.Anonymity in the context of social media refers to the separation of an individual's online and offline identity by making the origin of their messages unspecified. Platforms that support anonymity have users that are more likely to depict their offline self accurately online (i.e Reddit). Comparatively, platforms with less constraints on anonymity are subject to users that portray their online and offline selves differently, thus creating a “persona”.
Self-driving vehicles Societal challenges Automated_Driving > Challenges > Societal challenges While the notion that consumers care more about ease to use than safety has been challenged, it still remains an important factor that has indirect effects on the public's intention to use autonomous vehicles. The trust factor studies the safety, data privacy and security protection of autonomous vehicles. A more trusted system has a positive impact on the consumer's decision to use autonomous vehicles.
Turingery Summary Turingery The logical structure of Tunny had been worked out by William Tutte and colleagues over several months ending in January 1942. Deriving the message key was called "setting" at Bletchley Park, but it was the derivation of the cam patterns—which was known as "wheel breaking"—that was the target of Turingery. German operator errors in transmitting more than one message with the same key, producing a "depth", allowed the derivation of that key. Turingery was applied to such a key stream to derive the cam settings.
Internal symmetries Summary Global_symmetry These two concepts, Lie and finite groups, are the foundation for the fundamental theories of modern physics. Symmetries are frequently amenable to mathematical formulations such as group representations and can, in addition, be exploited to simplify many problems. Arguably the most important example of a symmetry in physics is that the speed of light has the same value in all frames of reference, which is described in special relativity by a group of transformations of the spacetime known as the Poincaré group. Another important example is the invariance of the form of physical laws under arbitrary differentiable coordinate transformations, which is an important idea in general relativity.
Learning theory (education) Multimedia learning Learning_theory_(education) > Multimedia learning Multimedia learning refers to the use of visual and auditory teaching materials that may include video, computer and other information technology. Multimedia learning theory focuses on the principles that determine the effective use of multimedia in learning, with emphasis on using both the visual and auditory channels for information processing. The auditory channel deals with information that is heard, and the visual channel processes information that is seen. The visual channel holds less information than the auditory channel.
Oriented cobordism Terminology Cobordism > Definition > Terminology An n-manifold M is called null-cobordant if there is a cobordism between M and the empty manifold; in other words, if M is the entire boundary of some (n + 1)-manifold. For example, the circle is null-cobordant since it bounds a disk. More generally, a n-sphere is null-cobordant since it bounds a (n + 1)-disk. Also, every orientable surface is null-cobordant, because it is the boundary of a handlebody.
Attention Restoration Theory Restorative environments Attention_Restoration_Theory > Restorative environments Fascination: the ability of an environment to generate awe in people; the amount of awe can give the directed attention a rest as the involuntary attention appears in its place. Being away: a feeling that can be objective or subjective in form, e.g. a person can be far away from a location or can let his or her mind go from everyday life and worries. Extension: the connection between each element found in an environment; the feeling of being able to travel through the environment in order to look for the information it provides. Compatibility: characteristics found in an environment that meet the preferences and goals of a person.
Multiset coefficient History Multiset_coefficient > History A multiset has been also called an aggregate, heap, bunch, sample, weighted set, occurrence set, and fireset (finitely repeated element set). : 320 Although multisets were used implicitly from ancient times, their explicit exploration happened much later. The first known study of multisets is attributed to the Indian mathematician Bhāskarāchārya circa 1150, who described permutations of multisets.
MRDP theorem Matiyasevich's theorem Matiyasevich's_theorem > Matiyasevich's theorem Matiyasevich's theorem, also called the Matiyasevich–Robinson–Davis–Putnam or MRDP theorem, says: Every computably enumerable set is Diophantine, and the converse.A set S of integers is computably enumerable if there is an algorithm such that: For each integer input n, if n is a member of S, then the algorithm eventually halts; otherwise it runs forever. That is equivalent to saying there is an algorithm that runs forever and lists the members of S. A set S is Diophantine precisely if there is some polynomial with integer coefficients f(n, x1, ..., xk) such that an integer n is in S if and only if there exist some integers x1, ..., xk such that f(n, x1, ..., xk) = 0. Conversely, every Diophantine set is computably enumerable: consider a Diophantine equation f(n, x1, ..., xk) = 0. Now we make an algorithm which simply tries all possible values for n, x1, ..., xk (in, say, some simple order consistent with the increasing order of the sum of their absolute values), and prints n every time f(n, x1, ..., xk) = 0. This algorithm will obviously run forever and will list exactly the n for which f(n, x1, ..., xk) = 0 has a solution in x1, ..., xk.
History of tuberculosis Conferences History_of_tuberculosis > References > Conferences Dang B (23–24 March 2001). "The Royal Touch". The Proceedings of the 10th Annual History of Medicine Days.
Concrete illustration of the central limit theorem Illustration of the continuous case Illustration_of_the_central_limit_theorem > Illustration of the continuous case Although the original density is far from normal, the density of the sum of just a few variables with that density is much smoother and has some of the qualitative features of the normal density. The convolutions were computed via the discrete Fourier transform. A list of values y = f(x0 + k Δx) was constructed, where f is the original density function, and Δx is approximately equal to 0.002, and k is equal to 0 through 1000. The discrete Fourier transform Y of y was computed. Then the convolution of f with itself is proportional to the inverse discrete Fourier transform of the pointwise product of Y with itself.
Central vacuum system Tools and accessories Central_vacuum > Tools and accessories Alternatively, a "DrawerVac" inlet which pulls out like a drawer from the underside of a table or counter can be used to dispose of debris from a shop or kitchen work surface. The "VacnSeal" is an accessory intended to be installed on the underside of a kitchen cabinet, over a countertop used for food preparation. The nozzle of the device is used to evacuate excess air from a zipper lock plastic food storage bag (e.g. Ziploc), which is said by the manufacturer to preserve food freshness for a longer period of time.
Dox Formation Contacts Dox_Formation > Contacts Typically, the surface of this unconformity is a remarkably flat, ancient erosional surface, often argued to be a peneplain, that cuts across units such as the Bass Formation, Hatakai Shale, and Dox Sandstone. Resistant beds within the Unkar Group, such as Cardenas Basalt and Shinumo Quartzite, form ancient hills, called monadnocks, that rise as much as 240 m (790 ft) high above this ancient plain. Thin drapes of Tapeats Sandstone of the Tonto Group now cover most of these ancient monadnocks.
Melphalan flufenamide Therapeutic efficacy Melphalan_flufenamide > Therapeutic efficacy In a Phase 1/2 trial, in solid tumor patients refractory to standard therapy, response evaluation showed disease stabilization in a majority of patients. In relapsed and refractory multiple-myeloma (RRMM) patients, promising activity was seen in heavily pre-treated RRMM patients where conventional therapies had failed; the median Progression-Free Survival was 9.4 months and the Duration of Response was 9.6 months.
Bridge financing Usage Bridge_loan > United Kingdom > Usage In the United Kingdom, bridging loans are used in both business and real estate. In the former, they are typically used to free equity in order to boost cash flow. In the latter, they are used by home-movers to ‘break’ property chains by providing a short-term source of finance when there is a delay between sale and completion dates, by buyers bidding on property at auction, and by landlords and property developers to secure renovation finance for quick sale or to refurbish a property that is considered uninhabitable prior to obtaining ordinary mortgage finance.
Schamel equation Schamel–Korteweg de Vries equation Schamel_equation > Generalizations > Schamel–Korteweg de Vries equation For 1 ≫ Q {\displaystyle 1\gg Q} we get ϕ ( x ) = ψ sech 2 ⁡ ( ψ 12 x ) {\displaystyle \phi (x)=\psi \operatorname {sech} ^{2}({\sqrt {\frac {\psi }{12}}}x)} which represents the ordinary ion acoustic soliton. The latter is fluid-like and is achieved for b = 0 {\displaystyle b=0} or β = 1 {\displaystyle \beta =1} representing an isothermal electron equation of state. Note that the absence of a trapping effect (b = 0) does not imply the absence of trapping, a statement that is usually misrepresented in the literature, especially in textbooks. As long as ψ {\displaystyle \psi } is nonzero, there is always a nonzero trapping width 2 2 ϕ {\displaystyle 2{\sqrt {2\phi }}} in velocity space for the electron distribution function.
Quantum theory of fields Topological quantum field theory Relativistic_quantum_field_theories > Principles > Other theories > Topological quantum field theory Chern–Simons theory is an example of TQFT and has been used to construct models of quantum gravity. Applications of TQFT include the fractional quantum Hall effect and topological quantum computers. : 1–5 The world line trajectory of fractionalized particles (known as anyons) can form a link configuration in the spacetime, which relates the braiding statistics of anyons in physics to the link invariants in mathematics. Topological quantum field theories (TQFTs) applicable to the frontier research of topological quantum matters include Chern-Simons-Witten gauge theories in 2+1 spacetime dimensions, other new exotic TQFTs in 3+1 spacetime dimensions and beyond.
Jet (fluid) Summary Jet_(fluid) A jet is a stream of fluid that is projected into a surrounding medium, usually from some kind of a nozzle, aperture or orifice. Jets can travel long distances without dissipating. Jet fluid has higher momentum compared to the surrounding fluid medium. In the case that the surrounding medium is assumed to be made up of the same fluid as the jet, and this fluid has a viscosity, the surrounding fluid is carried along with the jet in a process called entrainment.Some animals, notably cephalopods, move by jet propulsion, as do rocket engines and jet engines.
Solar thermal energy Heat storage for electric base loads Solar_thermal_energy > Heat storage for electric base loads Heat storage allows a solar thermal plant to produce electricity at night and on overcast days. This allows the use of solar power for baseload generation as well as peak power generation, with the potential of displacing both coal- and natural gas-fired power plants. Additionally, the utilization of the generator is higher which reduces cost.
Schotten–Baumann reaction Summary Schotten–Baumann_reaction The Schotten–Baumann reaction is a method to synthesize amides from amines and acid chlorides: Schotten–Baumann reaction also refers to the conversion of acid chloride to esters. The reaction was first described in 1883 by German chemists Carl Schotten and Eugen Baumann.The name "Schotten–Baumann reaction conditions" often indicate the use of a two-phase solvent system, consisting of water and an organic solvent. The base within the water phase neutralizes the acid, generated in the reaction, while the starting materials and product remain in the organic phase, often dichloromethane or diethyl ether.
Chromatin structure Additional sources Chromatin > References > Additional sources 92 (4): 511–521. doi:10.1016/s0092-8674(00)80944-7. PMID 9491892.

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