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Iteration Implementations Iterate_(math) > Computing > Implementations Loops constitute the most common language constructs for performing iterations. The following pseudocode "iterates" three times the line of code between begin & end through a for loop, and uses the values of i as increments. It is permissible, and often necessary, to use values from other parts of the program outside the bracketed block of statements, to perform the desired function. Iterators constitute alternative language constructs to loops, which ensure consistent iterations over specific data structures.
Functional completeness Summary Functional_completeness A gate or set of gates which is functionally complete can also be called a universal gate / gates. A functionally complete set of gates may utilise or generate 'garbage bits' as part of its computation which are either not part of the input or not part of the output to the system. In a context of propositional logic, functionally complete sets of connectives are also called (expressively) adequate.From the point of view of digital electronics, functional completeness means that every possible logic gate can be realized as a network of gates of the types prescribed by the set. In particular, all logic gates can be assembled from either only binary NAND gates, or only binary NOR gates.
Optical device Dispersion and scattering Optics > Classical optics > Physical optics > Dispersion and scattering Refractive processes take place in the physical optics limit, where the wavelength of light is similar to other distances, as a kind of scattering. The simplest type of scattering is Thomson scattering which occurs when electromagnetic waves are deflected by single particles. In the limit of Thomson scattering, in which the wavelike nature of light is evident, light is dispersed independent of the frequency, in contrast to Compton scattering which is frequency-dependent and strictly a quantum mechanical process, involving the nature of light as particles. In a statistical sense, elastic scattering of light by numerous particles much smaller than the wavelength of the light is a process known as Rayleigh scattering while the similar process for scattering by particles that are similar or larger in wavelength is known as Mie scattering with the Tyndall effect being a commonly observed result.
Hypocomplementemic vasculitis Diagnosis Hypocomplementemic_vasculitis > Diagnosis A rare autoimmune disease characterized by recurrent urticaria (nettle rash), first described in the 1970s. There is no defined paradigm for the syndrome aetiology and severity in progression. Diagnosis is confirmed with the identification of at least two conditions from: venulitis on skin biopsy, arthritis, ocular inflammation, abdominal pain or positive C1q antibodies to immune complexes. It is this last category, anti-C1q antibodies, that all HUV patients test positive for. In vitro experiments and mouse models of the disease have not thoroughly determined the link between these antibodies and the disease, even though the link is so pronounced.
Passing away Natural selection Passing_away > In biology > Natural selection The contemporary evolutionary theory sees death as an important part of the process of natural selection. It is considered that organisms less adapted to their environment are more likely to die, having produced fewer offspring, thereby reducing their contribution to the gene pool. Their genes are thus eventually bred out of a population, leading at worst to extinction and, more positively, making the process possible, referred to as speciation. Frequency of reproduction plays an equally important role in determining species survival: an organism that dies young but leaves numerous offspring displays, according to Darwinian criteria, much greater fitness than a long-lived organism leaving only one.Death also has a role in competition, where if a species out-competes another, there is a risk of death for the population. Especially in the case where they are directly fighting over resources.
Enriched grain Different forms of micronutrients Food_fortification > Criticism > Different forms of micronutrients There is a concern that micronutrients are legally defined in such a way that does not distinguish between different forms, and that fortified foods often have nutrients in a balance that would not occur naturally. For example, in the U.S., food is fortified with folic acid, which is one of the many naturally-occurring forms of folate, and which only contributes a minor amount to the folates occurring in natural foods. In many cases, such as with folate, it is an open question of whether or not there are any benefits or risks to consuming folic acid in this form.In many cases, the micronutrients added to foods in fortification are synthetic.Certain forms of micronutrients can be actively toxic in a sufficiently high dose, even if other forms are safe at the same or much higher doses. There are examples of such toxicity in both synthetic and naturally occurring forms of vitamins. Retinol, the active form of Vitamin A, is toxic in a much lower dose than other forms, such as beta carotene. Menadione, a phased-out synthetic form of Vitamin K, is also known to be toxic.
Encapsulation (object-oriented programming) Meaning Encapsulation_(object-oriented_programming) > Meaning In object-oriented programming languages, and other related fields, encapsulation refers to one of two related but distinct notions, and sometimes to the combination thereof: A language mechanism for restricting direct access to some of the object's components. A language construct that facilitates the bundling of data with the methods (or other functions) operating on those data.Some programming language researchers and academics use the first meaning alone or in combination with the second as a distinguishing feature of object-oriented programming, while some programming languages that provide lexical closures view encapsulation as a feature of the language orthogonal to object orientation. The second definition is motivated by the fact that in many object-oriented languages, and other related fields, the components are not hidden automatically and this can be overridden; thus, information hiding is defined as a separate notion by those who prefer the second definition. The features of encapsulation are supported using classes in most object-oriented languages, although other alternatives also exist.
Discrete log problem Algorithms Discrete_logarithm_problem > Algorithms For example, in the group of the integers modulo p under addition, the power bk becomes a product bk, and equality means congruence modulo p in the integers. The extended Euclidean algorithm finds k quickly. With Diffie–Hellman a cyclic group modulus a prime p is used, allowing an efficient computation of the discrete logarithm with Pohlig–Hellman if the order of the group (being p−1) is sufficiently smooth, i.e. has no large prime factors.
Refraction of light Sound waves Refraction > Mechanical waves > Sound waves In underwater acoustics, refraction is the bending or curving of a sound ray that results when the ray passes through a sound speed gradient from a region of one sound speed to a region of a different speed. The amount of ray bending is dependent on the amount of difference between sound speeds, that is, the variation in temperature, salinity, and pressure of the water. Similar acoustics effects are also found in the Earth's atmosphere. The phenomenon of refraction of sound in the atmosphere has been known for centuries; however, beginning in the early 1970s, widespread analysis of this effect came into vogue through the designing of urban highways and noise barriers to address the meteorological effects of bending of sound rays in the lower atmosphere.
Queueing network Queueing networks Queuing_theory > Queueing networks Queue networks are systems in which multiple queues are connected by customer routing. When a customer is serviced at one node, it can join another node and queue for service, or leave the network. For networks of m nodes, the state of the system can be described by an m–dimensional vector (x1, x2, ..., xm) where xi represents the number of customers at each node. The simplest non-trivial networks of queues are called tandem queues.
Periodic table (electron configurations) Summary Periodic_table_(electron_configurations) Written out, these are:He, 2, helium: 1s2 Ne, 10, neon: 1s2 2s2 2p6 Ar, 18, argon: 1s2 2s2 2p6 3s2 3p6 Kr, 36, krypton: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 Xe, 54, xenon: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 Rn, 86, radon: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 Og, 118, oganesson: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d10 7p6Note that these electron configurations are given for neutral atoms in the gas phase, which are not the same as the electron configurations for the same atoms in chemical environments. In many cases, multiple configurations are within a small range of energies and the small irregularities that arise in the d- and f-blocks are quite irrelevant chemically. The construction of the periodic table ignores these irregularities and is based on ideal electron configurations. Note the non-linear shell ordering, which comes about due to the different energies of smaller and larger shells.
Cell cycle progression DNA replication and DNA replication origin activity Cell_division_cycle > Regulation of eukaryotic cell cycle > DNA replication and DNA replication origin activity Analyses of synchronized cultures of Saccharomyces cerevisiae under conditions that prevent DNA replication initiation without delaying cell cycle progression showed that origin licensing decreases the expression of genes with origins near their 3' ends, revealing that downstream origins can regulate the expression of upstream genes. This confirms previous predictions from mathematical modeling of a global causal coordination between DNA replication origin activity and mRNA expression, and shows that mathematical modeling of DNA microarray data can be used to correctly predict previously unknown biological modes of regulation.
CCR5 receptor HIV CCR5_receptor > HIV During HIV-1 infection, the Gp120 envelope glycoprotein subunit binds to a CD4 glycoprotein and a HIV-1 co-receptor expressed on a target cell, forming a heterotrimeric complex. The formation of this complex stimulates the release of a fusogenic peptide, causing the viral membrane to fuse with the membrane of the target host cell. Because binding to CD4 alone can sometimes result in gp120 shedding, gp120 must next bind to co-receptor CCR5 in order for fusion to proceed.
Electric friction brake Summary Electric_friction_brake An electric friction brake, often referred to as just electric brake or electric trailer brake, is a brake controlled by an electric current and can be seen on medium duty trailers like caravans/RVs and consumer-grade car trailers. It is related to the electromagnetic track brake used in railways which also use electric current to directly control the brake force.
NP class Summary Nondeterministic_polynomial These two definitions are equivalent because the algorithm based on the Turing machine consists of two phases, the first of which consists of a guess about the solution, which is generated in a nondeterministic way, while the second phase consists of a deterministic algorithm that verifies whether the guess is a solution to the problem.It is easy to see that the complexity class P (all problems solvable, deterministically, in polynomial time) is contained in NP (problems where solutions can be verified in polynomial time), because if a problem is solvable in polynomial time, then a solution is also verifiable in polynomial time by simply solving the problem. But NP contains many more problems, the hardest of which are called NP-complete problems. An algorithm solving such a problem in polynomial time is also able to solve any other NP problem in polynomial time.
The Bridges Organization Summary The_Bridges_Organization The Bridges Organization is an organization that was founded in Kansas, United States, in 1998 with the goal of promoting interdisciplinary work in mathematics and art. The Bridges Conference is an annual conference on connections between art and mathematics. The conference features papers, educational workshops, an art exhibition, a mathematical poetry reading, and a short movie festival.
Histone H4 Summary Histone_H4 Covalently bonded modifications include acetylation and methylation of the N-terminal tails. These modifications may alter expression of genes located on DNA associated with its parent histone octamer. Histone H4 is an important protein in the structure and function of chromatin, where its sequence variants and variable modification states are thought to play a role in the dynamic and long term regulation of genes.
Function prologue Prologue Function_prologue > Prologue A function prologue typically does the following actions if the architecture has a base pointer (also known as frame pointer) and a stack pointer: Pushes current base pointer onto the stack, so it can be restored later. Value of base pointer is set to the address of stack pointer (which is pointed to the top of the stack) so that the base pointer will point to the top of the stack. Moves the stack pointer further by decreasing or increasing its value, depending on whether the stack grows down or up. On x86, the stack pointer is decreased to make room for the function's local variables.Several possible prologues can be written, resulting in slightly different stack configuration.
Cyclin-dependent kinase 6 Cell cycle Cyclin-dependent_kinase_6 > Function > Cell cycle In 1994, Matthew Meyerson and Ed Harlow investigated the product of a close analogous gene of CDK4. This gene, identified as PLSTIRE was translated into a protein that interacted with the cyclins CD1, CD2 and CD3 (same as CDK4), but that was different from CDK4; the protein was then renamed CDK6 for simplicity. In mammalian cells, cell cycle is activated by CDK6 in the early G1 phase through interactions with cyclins D1, D2 and D3. There are many changes in gene expression that are regulated through this enzyme.
Metal carbido complex Doubly bridging carbide ligands Carbide_cluster > Doubly bridging carbide ligands Bridging carbido ligands can be subdivided into three classes: cumulenic LnM=C=M'Ln, metallocarbyne LnM≡C−M'Ln, and polar covalent LnM≡C:→M'Ln.Cumulenic compounds generally bridge two metal atoms of the same element and are symmetrical. However, there are exceptions to this.In contrast, metallocarbyne compounds are generally constitutionally heterobimetallic, with complexes containing varying coordination geometries being common. These moieties have been able to serve as precursors to elaborate molecular scaffolds such as porphyrin derivatives.The polar covalent class is distinguished from metallocarbynes by a very fine line. This carbide-metal interaction is considered labile in nature. Carbon here can be understood fundamentally as being similar to CO ligands, that is, dative (L-type). Although, this class has also been described to some extent being analogous to the behavior of Lewis acid adduct-forming terminal nitrido and oxo complexes e.g. (PMe2Ph)2Cl-Re≡N-BCl3 and tBu(CH2)3(Br)W=O-AlBr3.
Scatter diagram Summary Scatter_diagram A scatter plot (also called a scatterplot, scatter graph, scatter chart, scattergram, or scatter diagram) is a type of plot or mathematical diagram using Cartesian coordinates to display values for typically two variables for a set of data. If the points are coded (color/shape/size), one additional variable can be displayed. The data are displayed as a collection of points, each having the value of one variable determining the position on the horizontal axis and the value of the other variable determining the position on the vertical axis.
Non-human primate experiments AIDS Primate_experimentation > Notable studies > AIDS The finding that prophylaxis can be effective at blocking infection has altered the treatment for occupational exposures, such as needle exposures. Such exposures are now followed rapidly with anti-HIV drugs, and this practice has resulted in measurable transient virus infection similar to the NHP model. Similarly, the mother-to-fetus transmission, and its fetal prophylaxis with antivirals such as tenofovir and AZT, has been evaluated in controlled testing in macaques not possible in humans, and this knowledge has guided antiviral treatment in pregnant mothers with HIV. "The comparison and correlation of results obtained in monkey and human studies is leading to a growing validation and recognition of the relevance of the animal model. Although each animal model has its limitations, carefully designed drug studies in nonhuman primates can continue to advance our scientific knowledge and guide future clinical trials."
Astronomia Nova Kepler's knowledge of gravity Astronomia_Nova > Kepler's knowledge of gravity His argument could easily be applied today to something like the flight of a hot air balloon. Nothing which consists of corporeal matter is absolutely light, but that is comparatively lighter which is rarer, either by its own nature, or by accidental heat. And it is not to be thought that light bodies are escaping to the surface of the universe while they are carried upwards, or that they are not attracted by the earth.
Force Touch Mechanics 3D_Touch > Mechanics The touch sensitive interface could either be a trackpad or a touch screen. Multiple actuators are mechanically connected to the back of the input surface. The actuators are distributed along the surface, each at a separate contact location, to provide localized haptic feedback to the user. Piezoelectricity is used by actuators to convert the physically-induced vibration or the input displacement into an electrical signal.
Consistency (database systems) Summary Data_inconsistency In database systems, consistency (or correctness) refers to the requirement that any given database transaction must change affected data only in allowed ways. Any data written to the database must be valid according to all defined rules, including constraints, cascades, triggers, and any combination thereof. This does not guarantee correctness of the transaction in all ways the application programmer might have wanted (that is the responsibility of application-level code) but merely that any programming errors cannot result in the violation of any defined database constraints.Consistency can also be understood as after a successful write, update or delete of a Record, any read request immediately receives the latest value of the Record.
Differential privacy Summary Differential_privacy Differential privacy (DP) is an approach for providing privacy while sharing information about a group of individuals, by describing the patterns within the group while withholding information about specific individuals. This is done by making arbitrary small changes to individual data that do not change the statistics of interest. Thus the data cannot be used to infer much about any individual.
Self awareness Schizophrenia Self_awareness > Disorders > Schizophrenia Schizophrenia is a chronic psychiatric illness characterized by excessive dopamine activity in the mesolimbic tract and insufficient dopamine activity in the mesocortical pathway, leading to symptoms of psychosis along with poor cognition in socialization. Under the Diagnostic and Statistical Manual of Mental Disorders, people with schizophrenia have a combination of positive, negative and psychomotor symptoms. These cognitive disturbances involve rare beliefs and/or thoughts of a distorted reality that creates an abnormal pattern of functioning for the patient. The cause of schizophrenia has a substantial genetic component involving many genes.
Erbin (protein) Summary Erbin_(protein) Erbb2 interacting protein (ERBB2IP), also known as erbin, is a protein which in humans is encoded by the ERBB2IP gene. Discovered in 1997, erbin is a 200kDa protein containing a PDZ domain.
Universal Grammar Argument Universal_Grammar > Argument Some students of universal grammar study a variety of grammars to extract generalizations called linguistic universals, often in the form of "If X holds true, then Y occurs." These have been extended to a variety of traits, such as the phonemes found in languages, the word orders which different languages choose, and the reasons why children exhibit certain linguistic behaviors. Other linguists who have influenced this theory include Richard Montague, who developed his version of this theory as he considered issues of the argument from poverty of the stimulus to arise from the constructivist approach to linguistic theory. The application of the idea of universal grammar to the study of second language acquisition (SLA) is represented mainly in the work of McGill linguist Lydia White. Syntacticians generally hold that there are parametric points of variation between languages, although heated debate occurs over whether UG constraints are essentially universal due to being "hard-wired" (Chomsky's principles and parameters approach), a logical consequence of a specific syntactic architecture (the generalized phrase structure approach) or the result of functional constraints on communication (the functionalist approach).
Hash table Other data structures for separate chaining Hash_tables > Collision resolution > Separate chaining > Other data structures for separate chaining If the keys are ordered, it could be efficient to use "self-organizing" concepts such as using a self-balancing binary search tree, through which the theoretical worst case could be brought down to O ( log ⁡ n ) {\displaystyle O(\log {n})} , although it introduces additional complexities. : 521 In dynamic perfect hashing, two-level hash tables are used to reduce the look-up complexity to be a guaranteed O ( 1 ) {\displaystyle O(1)} in the worst case. In this technique, the buckets of k {\displaystyle k} entries are organized as perfect hash tables with k 2 {\displaystyle k^{2}} slots providing constant worst-case lookup time, and low amortized time for insertion. A study shows array-based separate chaining to be 97% more performant when compared to the standard linked list method under heavy load. : 99 Techniques such as using fusion tree for each buckets also result in constant time for all operations with high probability.
Direct function History Direct_function > History Dfns were first presented in the Dyalog Vendor Forum at the APL '96 Conference and released in Dyalog APL in early 1997. Acceptance and recognition were slow in coming. As late as 2008, in Dyalog at 25, a publication celebrating the 25th anniversary of Dyalog Limited, dfns were barely mentioned (mentioned twice as "dynamic functions" and without elaboration). As of 2019, dfns are implemented in Dyalog APL, NARS2000, and ngn/apl. They also play a key role in efforts to exploit the computing abilities of a graphics processing unit (GPU).
Leaky bucket Uses Leaky_bucket > As a queue > Uses The leaky bucket as a queue can only be used in shaping traffic to a specified bandwidth with no jitter in the output. It may be used within the network, e.g. as part of bandwidth management, but is more appropriate to traffic shaping in the network interfaces of hosts. Leaky bucket algorithm is used in Nginx's ngx_http_limit_conn_module module for limiting the number of concurrent connections originating from a single IP address.
Instrument effect Summary Instrument_effect The instrument effect is an issue in experimental methodology meaning that any change during the measurement, or, the instrument, may influence the research validity. For example, in a control group design experiment, if the instruments used to measure the performance of the experiment group and the control group are different, a wrong conclusion about the experiment would be reached, the research result would be invalid. == References ==
Permutation group Summary Oligomorphic_group In mathematics, a permutation group is a group G whose elements are permutations of a given set M and whose group operation is the composition of permutations in G (which are thought of as bijective functions from the set M to itself). The group of all permutations of a set M is the symmetric group of M, often written as Sym(M). The term permutation group thus means a subgroup of the symmetric group. If M = {1, 2, ..., n} then Sym(M) is usually denoted by Sn, and may be called the symmetric group on n letters.
Thermochemical cycle Summary Thermochemical_cycle Thermochemical cycles combine solely heat sources (thermo) with chemical reactions to split water into its hydrogen and oxygen components. The term cycle is used because aside of water, hydrogen and oxygen, the chemical compounds used in these processes are continuously recycled. If work is partially used as an input, the resulting thermochemical cycle is defined as a hybrid one.
Lawrence Hunter Summary Lawrence_Hunter Lawrence E. Hunter is a Professor and Director of the Center for Computational Pharmacology and of the Computational Bioscience Program at the University of Colorado School of Medicine and Professor of Computer Science at the University of Colorado Boulder. He is an internationally known scholar, focused on computational biology, knowledge-driven extraction of information from the primary biomedical literature, the semantic integration of knowledge resources in molecular biology, and the use of knowledge in the analysis of high-throughput data, as well as for his foundational work in computational biology, which led to the genesis of the major professional organization in the field and two international conferences.
DNA code construction Introduction DNA_code_construction > Introduction The field of DNA computing was established in Leonard M. Adelman's seminal paper. His work is significant for a number of reasons: It shows how one could use the highly parallel nature of computation performed by DNA to solve problems that are difficult or almost impossible to solve using the traditional methods. It's an example of computation at a molecular level, on the lines of nanocomputing, and this potentially is a major advantage as far as the information density on storage media is considered, which can never be reached by the semiconductor industry.
Supersymmetric theory of stochastic dynamics Ambiguity of path integral representation and Ito–Stratonovich dilemma Supersymmetric_theory_of_stochastic_dynamics > BRST procedure for SDEs of arbitrary form > Ambiguity of path integral representation and Ito–Stratonovich dilemma Noteworthy, unlike in Langevin SDEs, d ¯ ^ α {\displaystyle {\hat {\bar {d}}}_{\alpha }} is not a supercharge and STS cannot be identified as a N=2 supersymmetric theory in the general case. The path integral representation of stochastic dynamics is equivalent to the traditional understanding of SDEs as of a continuous time limit of stochastic difference equations where different choices of parameter α {\displaystyle \alpha } are called "interpretations" of SDEs. The choice α = 1 / 2 {\displaystyle \alpha =1/2} , for which F 1 / 2 = F {\displaystyle \textstyle F_{1/2}=F} and which is known in quantum theory as Weyl symmetrization rule, is known as the Stratonovich interpretation, whereas α = 1 {\displaystyle \alpha =1} as the Ito interpretation. While in quantum theory the Weyl symmetrization is preferred because it guarantees hermiticity of Hamiltonians, in STS the Stratonovich–Weyl approach is preferred because it corresponds to the most natural mathematical meaning of the finite-time SEO discussed below—the stochastically averaged pullback induced by the SDE-defined diffeomorphisms.
Georgi–Glashow model Decomposition Georgi–Glashow_model > Minimal supersymmetric SU(5) > Vacua > Decomposition The Higgs mechanism causes one real HALF of the ( 3 , 2 ) − 5 6 {\displaystyle \ (3,2)_{-{\frac {5}{6}}}\ } and ( 3 ¯ , 2 ) 5 6 {\displaystyle \ ({\bar {3}},2)_{\frac {5}{6}}\ } of the adjoint Higgs to be absorbed. The other real half acquires a mass coming from the D-terms. And the other three components of the adjoint Higgs, ( 8 , 1 ) 0 , ( 1 , 3 ) 0 {\displaystyle \ (8,1)_{0},(1,3)_{0}\ } and ( 1 , 1 ) 0 {\displaystyle \ (1,1)_{0}\ } acquire GUT scale masses coming from self pairings of the superpotential, a Φ 2 + b < Φ > Φ 2 .
Free fatty acid receptor 2 Type 2 diabetes Free_fatty_acid_receptor_2 > FFAR2 functions and actions > Diabetes > Type 2 diabetes GIP also slows gastric motility. In addition, both GLP-1 and GIP protect pancreatic beta cells from dying by apoptosis (see programmed cell death).
Market intelligence Method of Validation Market_intelligence > Framework > Validation > Method of Validation Data cleansing is a complex process that involves several stages in order to get good data quality for MI strategy use. Stages include defining the organization's level of data quality, detecting error from the data collected and then repairing the errors. The five stages of data cleansing are data analysis to identify errors, eliminating the errors, checking to ensure elimination of error are done appropriately, refreshing the data in the data warehouse and finally replacing the dirty data with clean data.
Capo (musical device) Summary Capo_(musical_device) A capo (short for capodastro, capo tasto or capotasto , Italian for "head of fretboard") is a device a musician uses on the neck of a stringed (typically fretted) instrument to transpose and shorten the playable length of the strings—hence raising the pitch. It is a common tool for players of guitars, mandolins, mandolas, banjos, ukuleles and bouzoukis. The word derives from the Italian capotasto, which means the nut of a stringed instrument. The earliest known use of capotasto is by Giovanni Battista Doni who, in his Annotazioni of 1640, uses it to describe the nut of a viola da gamba.
Regression diagnostic Summary Regression_diagnostics In statistics, a regression diagnostic is one of a set of procedures available for regression analysis that seek to assess the validity of a model in any of a number of different ways. This assessment may be an exploration of the model's underlying statistical assumptions, an examination of the structure of the model by considering formulations that have fewer, more or different explanatory variables, or a study of subgroups of observations, looking for those that are either poorly represented by the model (outliers) or that have a relatively large effect on the regression model's predictions. A regression diagnostic may take the form of a graphical result, informal quantitative results or a formal statistical hypothesis test, each of which provides guidance for further stages of a regression analysis.
Fréchet derivative Relation to the Gateaux derivative Fréchet_differentiable > Relation to the Gateaux derivative The following example only works in infinite dimensions. Let X {\displaystyle X} be a Banach space, and φ {\displaystyle \varphi } a linear functional on X {\displaystyle X} that is discontinuous at x = 0 {\displaystyle x=0} (a discontinuous linear functional). Let Then f ( x ) {\displaystyle f(x)} is Gateaux differentiable at x = 0 {\displaystyle x=0} with derivative 0. {\displaystyle 0.} However, f ( x ) {\displaystyle f(x)} is not Fréchet differentiable since the limit does not exist.
Nuclear magnetic resonance spectroscopy of nucleic acids Structure determination Nucleic_acid_NMR > Structure determination For RNA, the differences in chemical structure and helix geometry make this assignment more technically difficult, but still possible. The sequential walking methodology is not possible for non-double helical nucleic acid structures, nor for the Z-DNA form, making assignment of resonances more difficult.Parameters taken from the spectrum, mainly NOESY cross-peaks and coupling constants, can be used to determine local structural features such as glycosidic bond angles, dihedral angles (using the Karplus equation), and sugar pucker conformations. The presence or absence of imino proton resonances, or of coupling between 15N atoms across a hydrogen bond, indicates the presence or absence of basepairing.
SARS-related coronavirus Replication and transcription SARS-associated_coronavirus > Life cycle > Replication and transcription A number of the nonstructural replication proteins coalesce to form a multi-protein replicase-transcriptase complex (RTC). The main replicase-transcriptase protein is the RNA-dependent RNA polymerase (RdRp). It is directly involved in the replication and transcription of RNA from an RNA strand. The other nonstructural proteins in the complex assist in the replication and transcription process.The protein nsp14 is a 3'-5' exoribonuclease which provides extra fidelity to the replication process.
Peter F. C. Gilbert Career and research Peter_F._C._Gilbert > Career and research Towards the end of 1974 and after completing his work in the Eccles laboratory, Gilbert partnered with Dr W. T. Thach at Yale School of Medicine. Over the next two years, and later, at Washington University School of Medicine, the pair carried out pioneering work on cerebellar motor learning. By recording from the Purkinje cells of conscious monkeys learning a manual task, Gilbert and Thach tested and confirmed theoretical predictions on motor learning in the cerebellum. Besides his experimental work, Gilbert has produced a number of theories on cerebellar motor learning and has published his theories in Nature and other journals. Since 2000, he has expanded his focus from the cerebellum to the entire brain; he is currently devoting his time to producing a unifying theory of brain function.
Circumventricular organs Function Circumventricular_organs > Sensory organs > Subfornical organ (SFO) > Function The induction of the drinking response via the SFO can be antagonized, however, by the peptide, ANP. Additional research has demonstrated that the subfornical organ may be an important intermediary though which leptin acts to maintain blood pressure within normal physiological limits via descending autonomic pathways associated with cardiovascular control.Recent research has focused on the subfornical organ as an area particularly important in the regulation of energy. The observation that subfornical neurons respond to a wide range of circulating energy balance signals, and that electrical stimulation of the SFO in rats resulted in food intake supports the SFO’s importance in energy homeostasis. Additionally, it is assumed that the SFO is the lone forebrain structure capable of constant monitoring of circulating concentrations of glucose. This responsiveness to glucose again serves to solidify the SFO’s integral role as a regulator of energy homeostasis.
Level ancestor problem Ladder algorithm Level_ancestor_problem > Ladder algorithm The ladder algorithm is based on the idea of simplifying a tree into a collection of paths. The reason for this is the fact that paths are easier to be queried when it comes to level ancestor queries. Consider a path P consisting of n nodes rooted at a node r. We can store the path into an array of size n called Ladder and we can quickly answer a level ancestor query of LA(v, d) by returning Ladder if depth(v)≤d. This will take O(1).
Homograph Summary Homograph However, in a broader sense the term "homonym" may be applied to words with the same writing or pronunciation. Homograph disambiguation is critically important in speech synthesis, natural language processing and other fields. Identically written different senses of what is judged to be fundamentally the same word are called polysemes; for example, wood (substance) and wood (area covered with trees).
Fisher transformation Definition Fisher_transformation > Definition Given a set of N bivariate sample pairs (Xi, Yi), i = 1, …, N, the sample correlation coefficient r is given by r = cov ⁡ ( X , Y ) σ X σ Y = ∑ i = 1 N ( X i − X ¯ ) ( Y i − Y ¯ ) ∑ i = 1 N ( X i − X ¯ ) 2 ∑ i = 1 N ( Y i − Y ¯ ) 2 . {\displaystyle r={\frac {\operatorname {cov} (X,Y)}{\sigma _{X}\sigma _{Y}}}={\frac {\sum _{i=1}^{N}(X_{i}-{\bar {X}})(Y_{i}-{\bar {Y}})}{{\sqrt {\sum _{i=1}^{N}(X_{i}-{\bar {X}})^{2}}}{\sqrt {\sum _{i=1}^{N}(Y_{i}-{\bar {Y}})^{2}}}}}.} Here cov ⁡ ( X , Y ) {\displaystyle \operatorname {cov} (X,Y)} stands for the covariance between the variables X {\displaystyle X} and Y {\displaystyle Y} and σ {\displaystyle \sigma } stands for the standard deviation of the respective variable. Fisher's z-transformation of r is defined as z = 1 2 ln ⁡ ( 1 + r 1 − r ) = artanh ⁡ ( r ) , {\displaystyle z={1 \over 2}\ln \left({1+r \over 1-r}\right)=\operatorname {artanh} (r),} where "ln" is the natural logarithm function and "artanh" is the inverse hyperbolic tangent function.
Generative grammar Summary Generative_grammar A main point of interest remains in how to appropriately analyse Wh-movement and other cases where the subject appears to separate the verb from the object. Although claimed by generativists as a cognitively real structure, neuroscience has found no evidence for it. In other words, generative grammar encompasses proposed models of linguistic cognition; but there is still no specific indication that these are quite correct. Recent arguments have been made that the success of large language models undermine key claims of generative syntax because they are based on markedly different assumptions, including gradient probability and memorized constructions, and out-perform generative theories both in syntactic structure and in integration with cognition and neuroscience.
Transducer Electromagnetic Transducer > Applications > Electromagnetic Antennae – converts propagating electromagnetic waves to and from conducted electrical signals magnetic cartridges – converts relative physical motion to and from electrical signals Tape head, disk read-and-write heads – converts magnetic fields on a magnetic medium to and from electrical signals Hall effect sensors – converts a magnetic field level into an electrical signal Pickup (music technology) – movement of metal strings induces an electrical signal (AC voltage)
Chemiluminescence Infrared chemiluminescence Infrared_chemiluminescence > Infrared chemiluminescence In chemical kinetics, infrared chemiluminiscence (IRCL) refers to the emission of infrared photons from vibrationally excited product molecules immediately after their formation. The intensities of infrared emission lines from vibrationally excited molecules are used to measure the populations of vibrational states of product molecules.The observation of IRCL was developed as a kinetic technique by John Polanyi, who used it to study the attractive or repulsive nature of the potential energy surface for gas-phase reactions. In general the IRCL is much more intense for reactions with an attractive surface, indicating that this type of surface leads to energy deposition in vibrational excitation. In contrast reactions with a repulsive potential energy surface lead to little IRCL, indicating that the energy is primarily deposited as translational energy.
Context-adaptive binary arithmetic coding Algorithm Context-adaptive_binary_arithmetic_coding > Algorithm Coding a data symbol involves the following stages. Binarization: CABAC uses Binary Arithmetic Coding which means that only binary decisions (1 or 0) are encoded. A non-binary-valued symbol (e.g. a transform coefficient or motion vector) is "binarized" or converted into a binary code prior to arithmetic coding.
Cutoff function Applications Cutoff_function > Applications The basic application of mollifiers is to prove that properties valid for smooth functions are also valid in nonsmooth situations:
Foundations of statistics Significance testing Foundations_of_statistics > Fisher's "significance testing" vs. Neyman–Pearson "hypothesis testing" > Significance testing Fisher played a significant role in popularizing significance testing through his publications, such as "Statistical Methods for Research Workers" in 1925 and "The Design of Experiments" in 1935. His aim was to achieve scientific experimental outcomes without bias from prior opinions. Significance testing is a probabilistic form of deductive inference, akin to modus tollens.
Dynamic list Linked lists vs. dynamic arrays Dynamic_list > Tradeoffs > Linked lists vs. dynamic arrays A balanced tree has similar memory access patterns and space overhead to a linked list while permitting much more efficient indexing, taking O(log n) time instead of O(n) for a random access. However, insertion and deletion operations are more expensive due to the overhead of tree manipulations to maintain balance. Schemes exist for trees to automatically maintain themselves in a balanced state: AVL trees or red–black trees.
Sustainable lifestyle Power Sustainable_living > Power Passive systems are cheaper than active systems since they do not require a pumping system (instead, they take advantage of the natural movement of hot water rising above cold water to cycle the water being used through the collector and storage tank).Other methods of harnessing solar power are solar space heating (for heating internal building spaces), solar drying (for drying wood chips, fruits, grains, etc.), solar cookers, solar distillers, and other passive solar technologies (simply, harnessing sunlight without any mechanical means). Wind power is harnessed through turbines, set on tall towers (typically 20’ or 6m with 10‘ or 3m diameter blades for an individual household's needs) that power a generator that creates electricity.
Inferential statistics Summary Predictive_inference Inferential statistics can be contrasted with descriptive statistics. Descriptive statistics is solely concerned with properties of the observed data, and it does not rest on the assumption that the data come from a larger population. In machine learning, the term inference is sometimes used instead to mean "make a prediction, by evaluating an already trained model"; in this context inferring properties of the model is referred to as training or learning (rather than inference), and using a model for prediction is referred to as inference (instead of prediction); see also predictive inference.
Matrix theory Orthogonal matrix Matrix_theory > Square matrix > Main types > Orthogonal matrix A special orthogonal matrix is an orthogonal matrix with determinant +1. As a linear transformation, every orthogonal matrix with determinant +1 is a pure rotation without reflection, i.e., the transformation preserves the orientation of the transformed structure, while every orthogonal matrix with determinant -1 reverses the orientation, i.e., is a composition of a pure reflection and a (possibly null) rotation. The identity matrices have determinant 1, and are pure rotations by an angle zero. The complex analogue of an orthogonal matrix is a unitary matrix.
One-third hypothesis Summary One-third_hypothesis This does not mean that these groups need to be dominant, but they play prominent roles." The OTH involves two mathematical curves. One represents the likelihood that a subgroup of a specific size will emerge; the other is the probability that it will persist. The product of the two curves is the one-third hypothesis.
One-shot learning (computer vision) Theory One-shot_learning_(computer_vision) > Theory The Bayesian one-shot learning algorithm represents the foreground and background of images as parametrized by a mixture of constellation models. During the learning phase, the parameters of these models are learned using a conjugate density parameter posterior and Variational Bayesian Expectation-Maximization (VBEM). In this stage the previously learned object categories inform the choice of model parameters via transfer by contextual information. For object recognition on new images, the posterior obtained during the learning phase is used in a Bayesian decision framework to estimate the ratio of p(object \| test, train) to p(background clutter \| test, train) where p is the probability of the outcome.
Spin angular momenta Rotations Spin_operator > Mathematical formulation > Rotations As described above, quantum mechanics states that components of angular momentum measured along any direction can only take a number of discrete values. The most convenient quantum-mechanical description of particle's spin is therefore with a set of complex numbers corresponding to amplitudes of finding a given value of projection of its intrinsic angular momentum on a given axis. For instance, for a spin-1/2 particle, we would need two numbers a±1/2, giving amplitudes of finding it with projection of angular momentum equal to +ħ/2 and −ħ/2, satisfying the requirement For a generic particle with spin s, we would need 2s + 1 such parameters. Since these numbers depend on the choice of the axis, they transform into each other non-trivially when this axis is rotated.
Humoral immune deficiency Summary B_cell_deficiency Humoral immune deficiencies are conditions which cause impairment of humoral immunity, which can lead to immunodeficiency. It can be mediated by insufficient number or function of B cells, the plasma cells they differentiate into, or the antibody secreted by the plasma cells. The most common such immunodeficiency is inherited selective IgA deficiency, occurring between 1 in 100 and 1 in 1000 persons, depending on population. They are associated with increased vulnerability to infection, but can be difficult to detect (or asymptomatic) in the absence of infection.
Beta thalassemia mRNA assembly Thalassemia_major > Cause > mRNA assembly Beta thalassemia is a hereditary disease affecting hemoglobin. As with about half of all hereditary diseases, an inherited mutation damages the assembly of the messenger-type RNA (mRNA) that is transcribed from a chromosome. DNA contains both the instructions (genes) for stringing amino acids together into proteins, as well as stretches of DNA that play important roles in regulating produced protein levels.In thalassemia, an additional, contiguous length or a discontinuous fragment of non-coding instructions is included in the mRNA. This happens because the mutation obliterates the boundary between the intronic and exonic portions of the DNA template.
Greenhouse warming Summary Greenhouse_Effect Adding to greenhouse gases further reduces the rate a planet emits radiation to space, raising its average surface temperature. The Earth's average surface temperature would be about −18 °C (−0.4 °F) without the greenhouse effect, compared to Earth's 20th century average of about 14 °C (57 °F), or a more recent average of about 15 °C (59 °F). In addition to naturally present greenhouse gases, burning of fossil fuels has increased amounts of carbon dioxide and methane in the atmosphere.
Brouwer fixed-point theorem Summary Brouwer_Fixed_Point_Theorem Proving results such as the Poincaré–Bendixson theorem requires the use of topological methods. This work at the end of the 19th century opened into several successive versions of the theorem. The case of differentiable mappings of the n-dimensional closed ball was first proved in 1910 by Jacques Hadamard and the general case for continuous mappings by Brouwer in 1911.
Measure theoretic Definition Measurable_set > Definition A triple ( X , Σ , μ ) {\displaystyle (X,\Sigma ,\mu )} is called a measure space. A probability measure is a measure with total measure one – that is, μ ( X ) = 1. {\displaystyle \mu (X)=1.}
Immune memory Summary Immunological_memory Immunological memory is the ability of the immune system to quickly and specifically recognize an antigen that the body has previously encountered and initiate a corresponding immune response. Generally, they are secondary, tertiary and other subsequent immune responses to the same antigen. The adaptive immune system and antigen-specific receptor generation (TCR, antibodies) are responsible for adaptive immune memory. After the inflammatory immune response to danger-associated antigen, some of the antigen-specific T cells and B cells persist in the body and become long-living memory T and B cells.
BERT (language model) Architecture BERT_(language_model) > Architecture Its vocabulary has size 30,000. Any token not appearing in its vocabulary is replaced by for "unknown". BERT was pre-trained simultaneously on two tasks:language modeling: 15% of tokens were selected for prediction, and the training objective was to predict the selected token given its context.
Depressive illness DSM and ICD criteria Unipolar_depression > Diagnosis > DSM and ICD criteria The most recent edition of the DSM is the Fifth Edition, Text Revision (DSM-5-TR), and the most recent edition of the ICD is the Eleventh Edition (ICD-11).Under mood disorders, ICD-11 classifies major depressive disorder as either single episode depressive disorder (where there is no history of depressive episodes, or of mania) or recurrent depressive disorder (where there is a history of prior episodes, with no history of mania). ICD-11 symptoms, present nearly every day for at least two weeks, are a depressed mood or anhedonia, accompanied by other symptoms such as "difficulty concentrating, feelings of worthlessness or excessive or inappropriate guilt, hopelessness, recurrent thoughts of death or suicide, changes in appetite or sleep, psychomotor agitation or retardation, and reduced energy or fatigue." These symptoms must affect work, social, or domestic activities.
Byerlee's law General references Byerlee's_law > References > General references MARGINS theoretical and experimental earth science series. Columbia University Press. ISBN 9780231127387.
Fiducial probability Background Fiducial_inference > Background However, in either case, the probability concerned is not the probability that the true value is in the particular interval that has been calculated since at that stage both the true value and the calculated interval are fixed and are not random. Credible intervals, in Bayesian inference, do allow a probability to be given for the event that an interval, once it has been calculated, does include the true value, since it proceeds on the basis that a probability distribution can be associated with the state of knowledge about the true value, both before and after the sample of data has been obtained.Fisher designed the fiducial method to meet perceived problems with the Bayesian approach, at a time when the frequentist approach had yet to be fully developed. Such problems related to the need to assign a prior distribution to the unknown values.
Quantitative analysis (finance) Library quantitative analysis Quantitative_analysis_(finance) > Types > Library quantitative analysis Major firms invest large sums in an attempt to produce standard methods of evaluating prices and risk. These differ from front office tools in that Excel is very rare, with most development being in C++, though Java, C# and Python are sometimes used in non-performance critical tasks. LQs spend more time modeling ensuring the analytics are both efficient and correct, though there is tension between LQs and FOQs on the validity of their results. LQs are required to understand techniques such as Monte Carlo methods and finite difference methods, as well as the nature of the products being modeled.
Tissue stress The place of the tissue stress in line of the unspecific adaptive reactions Tissue_stress > The place of the tissue stress in line of the unspecific adaptive reactions It consists in the formation of the protective phase of this physiological reaction. Meanwhile, under tissue stress, its protective function may be carried out both the “passive” and “active” CURD-induced mechanisms.
Parkinson disease Signs and symptoms Parkinsonian_tremor > Signs and symptoms The most recognizable symptoms are movement (motor) related, and include tremor, bradykinesia, rigidity, and shuffling/stooped gait. Non-motor symptoms, including autonomic dysfunction (dysautonomia), neuropsychiatric problems (mood, cognition, behavior or thought alterations), and sensory (especially altered sense of smell) and sleep difficulties may be present as well. Patients may have non-motor symptoms that precede the onset of motor symptoms including constipation, anosmia, and REM Behavior Disorder. Generally, symptoms such as dementia, psychosis, orthostasis, and more severe falls occur later. Dysphagia can begin at any time during the course of Parkinson's, and affects more than 80% of patients.
Universal hashing Introduction Universal_hashing > Introduction A family of functions H = { h: U → } {\displaystyle H=\{h:U\to \}} is called a universal family if, ∀ x , y ∈ U , x ≠ y: \| { h ∈ H: h ( x ) = h ( y ) } \| ≤ \| H \| m {\displaystyle \forall x,y\in U,~x\neq y:~~\|\{h\in H:h(x)=h(y)\}\|\leq {\frac {\|H\|}{m}}} . In other words, any two different keys of the universe collide with probability at most 1 / m {\displaystyle 1/m} when the hash function h {\displaystyle h} is drawn uniformly at random from H {\displaystyle H} . This is exactly the probability of collision we would expect if the hash function assigned truly random hash codes to every key.
Diffraction limit Digital photography Abbe_diffraction_limit > Calculation of diffraction limit > Digital photography In a digital camera, diffraction effects interact with the effects of the regular pixel grid. The combined effect of the different parts of an optical system is determined by the convolution of the point spread functions (PSF). The point spread function of a diffraction limited lens is simply the Airy disk. The point spread function of the camera, otherwise called the instrument response function (IRF) can be approximated by a rectangle function, with a width equivalent to the pixel pitch.
Complementary cumulative distribution function Properties Cumulative_distribution_function > Properties If X {\displaystyle X} is a purely discrete random variable, then it attains values x 1 , x 2 , … {\displaystyle x_{1},x_{2},\ldots } with probability p i = p ( x i ) {\displaystyle p_{i}=p(x_{i})} , and the CDF of X {\displaystyle X} will be discontinuous at the points x i {\displaystyle x_{i}}: If the CDF F X {\displaystyle F_{X}} of a real valued random variable X {\displaystyle X} is continuous, then X {\displaystyle X} is a continuous random variable; if furthermore F X {\displaystyle F_{X}} is absolutely continuous, then there exists a Lebesgue-integrable function f X ( x ) {\displaystyle f_{X}(x)} such that for all real numbers a {\displaystyle a} and b {\displaystyle b} . The function f X {\displaystyle f_{X}} is equal to the derivative of F X {\displaystyle F_{X}} almost everywhere, and it is called the probability density function of the distribution of X {\displaystyle X} . If X {\displaystyle X} has finite L1-norm, that is, the expectation of \| X \| {\displaystyle \|X\|} is finite, then the expectation is given by the Riemann–Stieltjes integral and for any x ≥ 0 {\displaystyle x\geq 0} , as shown in the diagram. In particular, we have
Called routine Conventions Algorithm_function > Conventions A wide number of conventions for the coding of functions have been developed. Pertaining to their naming, many developers have adopted the approach that the name of a function should be a verb when it does a certain task, and adjective when it makes some inquiry, and a noun when it is used to substitute variables. Some programmers suggest that a function should perform only one task, and if a function does perform more than one task, it should be split up into more functions. They argue that functions are key components in code maintenance, and their roles in the program must remain distinct.
D-dimer Indications D-dimer > Indications A low pretest probability is also valuable in ruling out PE. If the D-dimer reads high, then further testing (ultrasound of the leg veins or lung scintigraphy or CT scanning) is required to confirm the presence of thrombus. Anticoagulant therapy may be started at this point or withheld until further tests confirm the diagnosis, depending on the clinical situation.In some hospitals, they are measured by laboratories after a form is completed showing the probability score and only if the probability score is low or intermediate.
Yuneec Power Drive 10 Design and development Yuneec_Power_Drive_10 > Design and development The Power Drive 10 is part of a family of scalable electric motor designs produced by Yuneec. The Power Drive 10+ produces the same power but at a reduced rpm.The family of engines is designed to use the company's own power controller, Lithium polymer battery pack and charger, as an integrated package of components. This ensures that all components are compatible and also removes the need for aircraft builders to separately source components.The Power Drive 10 is a brushless 67 volt design producing 10 kW (13 hp), with an outrunner. The low working rpm of the engine means that it can turn a propeller at efficient speeds without the need for a reduction drive.
Grundzüge der physiologischen Psychologie Books and articles Grundzüge_der_physiologischen_Psychologie > Selected works > Books and articles 1878). Die physikalischen Axiome und ihre Beziehung zum Causalprincip (Physical Axioms and their Bearing upon Causality Principles), (Enke, Erlangen 1866). Handbuch der medicinischen Physik (Handbook of Medical Physics), (Enke, Erlangen 1867).
Quantum Field Theory Renormalization group Relativistic_quantum_field_theories > Principles > Renormalization > Renormalization group The renormalization group, developed by Kenneth Wilson, is a mathematical apparatus used to study the changes in physical parameters (coefficients in the Lagrangian) as the system is viewed at different scales. : 393 The way in which each parameter changes with scale is described by its β function. : 417 Correlation functions, which underlie quantitative physical predictions, change with scale according to the Callan–Symanzik equation. : 410–411 As an example, the coupling constant in QED, namely the elementary charge e, has the following β function: β ( e ) ≡ 1 Λ d e d Λ = e 3 12 π 2 + O ( e 5 ) , {\displaystyle \beta (e)\equiv {\frac {1}{\Lambda }}{\frac {de}{d\Lambda }}={\frac {e^{3}}{12\pi ^{2}}}+O{\mathord {\left(e^{5}\right)}},} where Λ is the energy scale under which the measurement of e is performed.
Numerical methods in fluid mechanics Forward Euler approximation Numerical_methods_in_fluid_mechanics > Forward Euler approximation u n + 1 − u n Δ t ≈ κ u n {\displaystyle {\frac {u^{n+1}-u^{n}}{\Delta t}}\approx \kappa u^{n}} Equation is an explicit approximation to the original differential equation since no information about the unknown function at the future time (n + 1)t has been used on the right hand side of the equation. In order to derive the error committed in the approximation we rely again on Taylor series.
Mechanical philosophy Summary Mechanical_philosophy There is no constant meaning in the history of philosophy for the word Mechanism. Originally, the term meant that cosmological theory which ascribes the motion and changes of the world to some external force. In this view material things are purely passive, while according to the opposite theory (i. e., Dynamism), they possess certain internal sources of energy which account for the activity of each and for its influence on the course of events; These meanings, however, soon underwent modification.
Relative standard deviation Alternative Coefficient_of_variation > Distribution > Alternative According to Liu (2012), Lehmann (1986). "also derived the sample distribution of CV in order to give an exact method for the construction of a confidence interval for CV;" it is based on a non-central t-distribution.
Hypothalamic–pituitary–thyroid axis Physiology HPT_axis > Physiology Thyroid homeostasis results from a multi-loop feedback system that is found in virtually all higher vertebrates. Proper function of thyrotropic feedback control is indispensable for growth, differentiation, reproduction and intelligence. Very few animals (e.g. axolotls and sloths) have impaired thyroid homeostasis that exhibits a very low set-point that is assumed to underlie the metabolic and ontogenetic anomalies of these animals. The pituitary gland secretes thyrotropin (TSH; Thyroid Stimulating Hormone) that stimulates the thyroid to secrete thyroxine (T4) and, to a lesser degree, triiodothyronine (T3).
Dereference operator C linked list Dereference_operator > Uses > Use in data structures > C linked list Below is an example definition of a linked list in C. This pointer-recursive definition is essentially the same as the reference-recursive definition from the Haskell programming language: Nil is the empty list, and Cons a (Link a) is a cons cell of type a with another link also of type a. The definition with references, however, is type-checked and does not use potentially confusing signal values. For this reason, data structures in C are usually dealt with via wrapper functions, which are carefully checked for correctness.
Principal value Complex argument Principal_value > General case > Principal values of standard functions > Complex argument The principal value of complex number argument measured in radians can be defined as: values in the range {\displaystyle (-\pi ,\pi ]} To compute these values one can use functions: atan2 with principal value in the range ( − π , π ] {\displaystyle (-\pi ,\pi ]} atan with principal value in the range ( − π 2 , π 2 ] {\displaystyle ({\tfrac {-\pi }{2}},{\tfrac {\pi }{2}}]}
Two-dimensional polymers (2DP) Summary Two-dimensional_polymer They are distinct from other families of polymers because 2D polymers can be isolated as multilayer crystals or as individual sheets.The term 2D polymer has also been used more broadly to include linear polymerizations performed at interfaces, layered non-covalent assemblies, or to irregularly cross-linked polymers confined to surfaces or layered films. 2D polymers can be organized based on these methods of linking (monomer interaction): covalently linked monomers, coordination polymers and supramolecular polymers. Topologically, 2DPs may thus be understood as structures made up from regularly tessellated regular polygons (the repeat units). Figure 1 displays the key features of a linear and a 2DP according to this definition. For usage of the term "2D polymer" in a wider sense, see "History".
Molecular orbital diagram Dihydrogen MO_diagram > Diatomic MO diagrams > Dihydrogen The bond order for dihydrogen is (2-0)/2 = 1. The photoelectron spectrum of dihydrogen shows a single set of multiplets between 16 and 18 eV (electron volts).The dihydrogen MO diagram helps explain how a bond breaks. When applying energy to dihydrogen, a molecular electronic transition takes place when one electron in the bonding MO is promoted to the antibonding MO.
Occupant-centric building controls Predictive Controls Occupant-centric_building_controls > Background > Predictive Controls Unlike reactive controls, predictive controls use real-time occupant preference and presence data to inform and train predictive control algorithms rather than directly impact the system operation. Predictive controls have a ‘prediction horizon’ which is the amount of time ahead that an OCC will need to change a setpoint or ventilation rate to achieve a certain temperature or indoor air quality level.
Polar covalent bond Nonpolar molecules Chemical_polarity > Examples > Nonpolar molecules A molecule may be nonpolar either when there is an equal sharing of electrons between the two atoms of a diatomic molecule or because of the symmetrical arrangement of polar bonds in a more complex molecule. For example, boron trifluoride (BF3) has a trigonal planar arrangement of three polar bonds at 120°. This results in no overall dipole in the molecule. Carbon dioxide (CO2) has two polar C=O bonds, but the geometry of CO2 is linear so that the two bond dipole moments cancel and there is no net molecular dipole moment; the molecule is nonpolar.
Frequency response (electrical grid) Control after disturbance Power_system_operations > Control after disturbance Small mismatches between the total demand and total load are typical and initially are taken care of by the kinetic energy of the rotating machinery (mostly synchronous generators): when there is too much supply, the devices absorb the excess, and frequency goes above the scheduled rate, conversely, too much demand causes the generator to deliver extra electricity through slowing down, with frequency slightly decreasing, not requiring an intervention from the operator. There are obvious limits to this "immediate control", so a control continuum is built into a typical power grid, spanning reaction intervals from seconds ("primary control") to hours ("time control").
Geometrized units Summary Geometric_units All physical quantities are identified with geometric quantities such as areas, lengths, dimensionless numbers, path curvatures, or sectional curvatures. Many equations in relativistic physics appear simpler when expressed in geometric units, because all occurrences of G and of c drop out. For example, the Schwarzschild radius of a nonrotating uncharged black hole with mass m becomes r = 2m.
Renormalization General introduction Renormalization > Further reading > General introduction Shirkov, Dmitry; Fifty Years of the Renormalization Group, C.E.R.N. Courrier 41(7) (2001). Full text available at: I.O.P Magazines. E. Elizalde; Zeta regularization techniques with Applications.
Signaling peptide receptor PAC1 Signaling_peptide_receptor > Vasoactive intestinal peptide receptor and Pituitary adenylate cyclase-activating peptide > PAC1 Agonists PACAP PACAP (1-27) PACAP (1-38) Antagonists PACAP (6-38)
Special Theory of Relativity Texts by Einstein and text about history of special relativity Relativistic_velocities > Further reading > Texts by Einstein and text about history of special relativity Einstein, Albert (1920). Relativity: The Special and General Theory. Einstein, Albert (1996). The Meaning of Relativity.

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