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Data type Function types Data_types > Examples > Function types Functional programming languages treat functions as a distinct datatype and allow values of this type to be stored in variables and passed to functions. Some multi-paradigm languages such as JavaScript also have mechanisms for treating functions as data. Most contemporary type systems go beyond JavaScript's simple type "function object" and have a family of function types differentiated by argument and return types, such as the type Int -> Bool denoting functions taking an integer and returning a boolean. In C, a function is not a first-class data type but function pointers can be manipulated by the program. Java and C++ originally did not have function values but have added them in C++11 and Java 8.
Geostationary Transfer Orbit Other considerations Geostationary_Transfer_Orbit > Other considerations Although some launchers can take their payloads all the way to geostationary orbit, most end their missions by releasing their payloads into GTO. The spacecraft and its operator are then responsible for the maneuver into the final geostationary orbit. The 5-hour coast to first apogee can be longer than the battery lifetime of the launcher or spacecraft, and the maneuver is sometimes performed at a later apogee or split among multiple apogees.
Determinant of a matrix Eigenvalues and characteristic polynomial Determinant > Properties of the determinant in relation to other notions > Eigenvalues and characteristic polynomial Then, it turns out the determinant of A is equal to the product of these eigenvalues, det ( A ) = ∏ i = 1 n λ i = λ 1 λ 2 ⋯ λ n . {\displaystyle \det(A)=\prod _{i=1}^{n}\lambda _{i}=\lambda _{1}\lambda _{2}\cdots \lambda _{n}.} The product of all non-zero eigenvalues is referred to as pseudo-determinant.
Thermodynamic equations The fundamental equation Thermodynamic_equations > The fundamental equation In other words: from which the following identifications can be made: These equations are known as "equations of state" with respect to the internal energy. (Note - the relation between pressure, volume, temperature, and particle number which is commonly called "the equation of state" is just one of many possible equations of state.) If we know all k+2 of the above equations of state, we may reconstitute the fundamental equation and recover all thermodynamic properties of the system. The fundamental equation can be solved for any other differential and similar expressions can be found. For example, we may solve for d S {\displaystyle dS} and find that
Pseudorandom generator In cryptography Pseudorandom_generator > In cryptography The existence of cryptographically secure pseudorandom generators is widely believed. This is because it has been proven that pseudorandom generators can be constructed from any one-way function which are believed to exist. Pseudorandom generators are necessary for many applications in cryptography. The pseudorandom generator theorem shows that cryptographically secure pseudorandom generators exist if and only if one-way functions exist.
Abstract thinking In social theory Abstract_thinking > As used in different disciplines > In social theory Breaking away from directly experienced reality was a common trend in 19th-century sciences (especially physics), and this was the effort which fundamentally determined the way economics tried (and still tries) to approach the economic aspects of social life. It is abstraction we meet in the case of both Newton's physics and the neoclassical theory, since the goal was to grasp the unchangeable and timeless essence of phenomena. For example, Newton created the concept of the material point by following the abstraction method so that he abstracted from the dimension and shape of any perceptible object, preserving only inertial and translational motion.
Oxidative Addition Role in transition metal chemistry Oxidative_Addition > Role in transition metal chemistry Although oxidative additions can occur with the insertion of a metal into many different substrates, oxidative additions are most commonly seen with H–H, H–X, and C–X bonds because these substrates are most relevant to commercial applications. Oxidative addition requires that the metal complex have a vacant coordination site. For this reason, oxidative additions are common for four- and five-coordinate complexes.
Knight's graph Summary Knight's_graph In graph theory, a knight's graph, or a knight's tour graph, is a graph that represents all legal moves of the knight chess piece on a chessboard. Each vertex of this graph represents a square of the chessboard, and each edge connects two squares that are a knight's move apart from each other. More specifically, an m × n {\displaystyle m\times n} knight's graph is a knight's graph of an m × n {\displaystyle m\times n} chessboard.
Classical Electrodynamics (book) Second edition Classical_Electrodynamics_(book) > Reception > Second edition Reviewer Royce Zia from the Virginia Polytechnic Institute wrote that according to many students and professors, a major problem with the first edition of the book was how mathematically heavy the book was, which distracted students from the essential physics. In the second edition, many issues were addressed, more insightful discussions added and misleading diagrams removed. Extended chapters on the applications of electromagnetism brought students closer to research.
Java collections framework ConcurrentSkipListMap class Collections_Framework > Map interfaces > Map interface implementations > AbstractMap class > ConcurrentSkipListMap class ConcurrentSkipListMap acts as a concurrent replacement for implementations of a synchronized SortedMap. ConcurrentSkipListMap is very similar to ConcurrentSkipListSet, since ConcurrentSkipListMap replaces a TreeMap that has been wrapped by the sychronizedMap method.
Communication privacy management theory Facebook Communication_privacy_management_theory > Theory applications > Online social media > Facebook Another case study analyzing the responses of 240 participants revealed that the communication privacy practices by individuals using Facebook strongly impact the “amount and depth” of their self-disclosure. One more study explored how colleagues in the professional context respond to friend requests from other co-workers. The study provided evidence that co-workers' connection on Facebook improves only when each party understands the rules which govern privacy management.
Periodic motion Driven oscillations Coupled_oscillation > Driven oscillations In addition, an oscillating system may be subject to some external force, as when an AC circuit is connected to an outside power source. In this case the oscillation is said to be driven. The simplest example of this is a spring-mass system with a sinusoidal driving force. where f ( t ) = f 0 cos ⁡ ( ω t + δ ) .
Friction-plate electromagnetic couplings Engagement time Electromagnetic_clutches_and_brakes > Engagement time The second one is air gap, which is the space between the armature and the coil shell or rotor. Magnetic lines of flux diminish quickly in the air. The further away the attractive piece is from the coil, the longer it will take for that piece to actually develop enough magnetic force to be attracted and pull in to overcome the air gap.
Model Transformation Language Available transformation languages Model_Transformation_Language > Available transformation languages Kermeta: a general purpose modeling and programming language, also able to perform transformations Lx family (see ): a set of low-level transformation languages M2M is the Eclipse implementation of the OMG QVT standard Mia-TL: a transformation language developed by Mia-Software MOF Model to Text Transformation Language: the OMG has defined a standard for expressing M2T transformations MOLA (see ): a graphical high-level transformation language built in upon Lx. MT: a transformation language developed at King's College, London (UK) (based on Converge PL) QVT: the OMG has defined a standard for expressing M2M transformations, called MOF/QVT or in short QVT. SiTra : a pragmatic transformation approach based on using a standard programming language, e.g. Java, C# Stratego/XT: a transformation language based on rewriting with programmable strategies Tefkat: a transformation language and a model transformation engine Tom: a language based on rewriting calculus, with pattern-matching and strategies UML-RSDS : a model transformation and MDD approach using UML and OCL VIATRA: a framework for transformation-based verification and validation environment
Cache coherency protocols (examples) RT-ST-MESI protocol Cache_coherency_protocols_(examples) > Coherency protocols > RT-ST-MESI protocol - In Read Miss, T is changed in ST1 and all the indices of the others STi are increased by "1. - In case of T deallocation, ST1 stops the "Copy Back" transaction, changes its state in T and all the indices of the others STi are decrease by "1". - In case of a deallocation, for instance STk, the chain will be interrupted and all the STi with index greater of "k" are automatically loosen in term of ST and will be considered de facto only as simple S states also if they are set as ST. All this because only ST1 intervenes to block and to replace itself with T. For instance if we have a situation type T, ST1, ST3, ST4 with ST2 replaced, if T will be replaced the new situation will be T, ST2, ST3 without any ST1.————————————————————————————————————————
Causality problem Casimir vacuum and quantum tunnelling Faster-than-light_travel > Justifications > Casimir vacuum and quantum tunnelling Other authors argue that Scharnhorst's original analysis, which seemed to show the possibility of faster-than-c signals, involved approximations which may be incorrect, so that it is not clear whether this effect could actually increase signal speed at all.The physicists Günter Nimtz and Alfons Stahlhofen, of the University of Cologne, claim to have violated relativity experimentally by transmitting photons faster than the speed of light. They say they have conducted an experiment in which microwave photons—relatively low-energy packets of light—travelled "instantaneously" between a pair of prisms that had been moved up to 3 ft (1 m) apart. Their experiment involved an optical phenomenon known as "evanescent modes", and they claim that since evanescent modes have an imaginary wave number, they represent a "mathematical analogy" to quantum tunnelling.
Lill's method Finding roots using paper folding Lill's_method > Description of the method > Finding roots using paper folding In 1936 Margherita Piazzola Beloch showed how Lill's method could be adapted to solve cubic equations using paper folding. If simultaneous folds are allowed then any nth degree equation with a real root can be solved using n–2 simultaneous folds.In this example with 3x3+2x2−7x+2, the polynomial's line segments are first drawn on a sheet of paper (black). Lines passing through reflections of the start and end points in the second and third segments, respectively (faint circle and square), and parallel to the them (grey lines) are drawn. For each root, the paper is folded until the start point (black circle) and end point (black square) are reflected onto these lines. The axis of reflection (dash-dot line) defines the angled path corresponding to the root (blue, purple and red). The negative of the gradients of their first segments, m, yield the real roots 1/3, 1 and −2.
Sulfatide HIV-1 Sulfatide > Role in pathological cells and tissue > Viral infection > HIV-1 Consequently, sulfatide acts as an alternate virus receptor in CD4- cells, and it participates in transmembrane signaling. However, sulfatide has little function in HIV-1 infection of CD4+ cells.The binding of gp120 to GalCer has the ability to start the fusion of HIV-1, but the binding of gp120 to sulfatide does not. Sulfatide is not a functional receptor.
Neurosexism Empathising–systemising theory Neurosexism > Examples in science > Empathising–systemising theory Boys tend to play with plastic cars, illustrating a more mechanical, system-driven mind. This may be of course due simply to the environment and to social norms. However, the empathising-systematising theory posits three broad brain types, or organisation structures: type E, the empathiser; type S, the systematiser; type B, the 'balanced brain'.
Systems Network Architecture Advantages Systems_Network_Architecture > Advantages and disadvantages > Advantages With the advent of Advanced Peer-to-Peer Networking (APPN), routing functionality was the responsibility of the computer as opposed to the router (as with TCP/IP networks). Each computer maintained a list of Nodes that defined the forwarding mechanisms. A centralized node type known as a Network Node maintained Global tables of all other node types.
Run-time estimation of system and sub-system level power consumption Power model validation through thermal measurements Run-time_estimation_of_system_and_sub-system_level_power_consumption > Direct Power measurement > Power model validation through thermal measurements The first step is to measure the temperature using IR camera and within the oil coolant that flows over the top of the chip surface, the detailed setup information is described in reference. Oil is chosen because of ease in modeling and accuracy. The infrared cameras must be calibrated to compensate for different material thermal emissions, lens configurations, and other factors in reference.
F14 CADC History F14_CADC > History The CADC was designed and built by a team led by Steve Geller and Ray Holt, and supported by the startup American Microsystems. Design work started in 1968 and was completed in June 1970, beating out a number of electromechanical systems that had also been designed for the F-14. It was classified by the Navy until 1998.
Metacentric height Metacentre Transverse_stability > Metacentre In the diagram above, the two Bs show the centres of buoyancy of a ship in the upright and heeled conditions. The metacentre, M, is considered to be fixed relative to the ship for small angles of heel; however, at larger angles the metacentre can no longer be considered fixed, and its actual location must be found to calculate the ship's stability. It can be calculated using the formulae: K M = K B + B M {\displaystyle KM=KB+BM} B M = I V {\displaystyle BM={\frac {I}{V}}\ } Where KB is the centre of buoyancy (height above the keel), I is the second moment of area of the waterplane around the rotation axis in metres4, and V is the volume of displacement in metres3.
Bacteriocin Class IV bacteriocins Bacteriocin > Classification > From Gram positive bacteria > Class IV bacteriocins Class IV bacteriocins are defined as complex bacteriocins containing lipid or carbohydrate moieties. Confirmation by experimental data was established with the characterisation of sublancin and glycocin F (GccF) by two independent groups.
Metropolis-Hastings algorithm Formal derivation Metropolis–Hastings_algorithm > Formal derivation Uniqueness of stationary distribution: the stationary distribution π ( x ) {\displaystyle \pi (x)} must be unique. This is guaranteed by ergodicity of the Markov process, which requires that every state must (1) be aperiodic—the system does not return to the same state at fixed intervals; and (2) be positive recurrent—the expected number of steps for returning to the same state is finite.The Metropolis–Hastings algorithm involves designing a Markov process (by constructing transition probabilities) that fulfills the two above conditions, such that its stationary distribution π ( x ) {\displaystyle \pi (x)} is chosen to be P ( x ) {\displaystyle P(x)} . The derivation of the algorithm starts with the condition of detailed balance: P ( x ′ ∣ x ) P ( x ) = P ( x ∣ x ′ ) P ( x ′ ) , {\displaystyle P(x'\mid x)P(x)=P(x\mid x')P(x'),} which is re-written as P ( x ′ ∣ x ) P ( x ∣ x ′ ) = P ( x ′ ) P ( x ) .
Semi-supervised learning Generative models Semisupervised_learning > Methods > Generative models If these assumptions are incorrect, the unlabeled data may actually decrease the accuracy of the solution relative to what would have been obtained from labeled data alone. However, if the assumptions are correct, then the unlabeled data necessarily improves performance.The unlabeled data are distributed according to a mixture of individual-class distributions. In order to learn the mixture distribution from the unlabeled data, it must be identifiable, that is, different parameters must yield different summed distributions.
Intelligent Systems for Molecular Biology Formation of ISCB and expansion Intelligent_Systems_for_Molecular_Biology > History > Formation of ISCB and expansion ISMB 1997 was held in Halkidiki, Greece and marked the foundation of the International Society for Computational Biology (ISCB). ISCB was formed with a focus on managing all scientific, organizational and financial aspects of the ISMB conference and to provide a forum for scientists to address the emerging role of computers in the biological sciences. ISCB has assisted in organising the ISMB conference series since 1998. The period following the formation of ISCB also marked an expansion in the number of ISMB attendees: ISMB 2000 (held at the University of California, San Diego) was attended by over 1,000 delegates, submitting 141 scientific papers. This meeting was also the last time ISMB would be held at a university, due to size limitations.
Splice variant analysis Regulatory elements and proteins Splice_variant_analysis > Mechanisms > Regulatory elements and proteins The context within which regulatory elements act includes cis-acting context that is established by the presence of other RNA sequence features, and trans-acting context that is established by cellular conditions. For example, some cis-acting RNA sequence elements influence splicing only if multiple elements are present in the same region so as to establish context. As another example, a cis-acting element can have opposite effects on splicing, depending on which proteins are expressed in the cell (e.g., neuronal versus non-neuronal PTB). The adaptive significance of splicing silencers and enhancers is attested by studies showing that there is strong selection in human genes against mutations that produce new silencers or disrupt existing enhancers.
Steady current Summary Steady_current A constant current (steady current, time-independent current, stationary current) is a type of direct current (DC) that does not change its intensity with time.
Theodore von Kármán bibliography 1960s Theodore_von_Kármán_bibliography > Papers > 1960s Fluid Dynamics and Applied Mathematics. ASIN B00K2Y0GSA. Kármán, Th.
Data vault modeling Links Data_vault_modeling > Basic notions > Links This is done only when there is no possibility of ever using the business key for another link or as key for attributes in a satellite. This construct has been called a 'peg-legged link' by Dan Linstedt on his (now defunct) forum. Links contain the surrogate keys for the hubs that are linked, their own surrogate key for the link and metadata describing the origin of the association. The descriptive attributes for the information on the association (such as the time, price or amount) are stored in structures called satellite tables which are discussed below.
Cellular differentiation Summary Terminal_differentiation Some differentiation occurs in response to antigen exposure. Differentiation dramatically changes a cell's size, shape, membrane potential, metabolic activity, and responsiveness to signals. These changes are largely due to highly controlled modifications in gene expression and are the study of epigenetics.
Human ethology Methodology Human_ethology > Methodology ‍‍Ethologists‍‍ study behavior using two general methods: naturalistic observation and laboratory experimentation. Ethologist's insistence on observing organisms in their natural environment differentiates ethology from related disciplines such as evolutionary psychology and sociobiology, and their naturalistic observation "ranks as one of their main contributions to psychology", Naturalistic Observation Ethologists believe that in order to study species-specific behaviors, a species must be observed in its natural environment. One can only understand the function of a behavior by seeing how it specifically fits into the ‍‍species‍‍ natural environment to fulfill a specific need. Ethologists follow a specific set of steps when studying an organism: These steps fall in line with Tinbergen's "On Aims of Methods of Ethology" in which he states that every study of behavior must answer four questions to be considered legitimate: function (adaptation) evolution (phylogeny) causation (mechanism) development (ontogeny)
History of scientific method Aristotle History_of_scientific_method > Early methodology > Aristotle Chapter 9 deals with the problem of future contingents. The Prior Analytics (Greek: Ἀναλυτικὰ Πρότερα, Latin: Analytica Priora) introduces Aristotle's syllogistic method (see term logic), argues for its correctness, and discusses inductive inference. The Posterior Analytics (Greek: Ἀναλυτικὰ Ὕστερα, Latin: Analytica Posteriora) deals with demonstration, definition, and scientific knowledge.
Exoplanet orbital and physical parameters Summary Exoplanetary_science This page describes exoplanet orbital and physical parameters.
Dimensional models of personality disorders Five-factor model Dimensional_models_of_personality_disorders > Model development > Normal personality models > Five-factor model Thomas Widiger and his colleagues have demonstrated that many of the central elements of personality disorders can be explained in terms of Big Five traits – for example, borderline personality disorder is characterized by high levels of hostility, trait anxiety and depression, and vulnerability, all of which are facets of neuroticism. This approach also helps to differentiate characteristics of disorders that overlap under the current categorical model, such as avoidant and schizoid personality disorders. The Five-Factor-based approach explains much of that overlap as well as the ways in which they are different.
Acute respiratory distress syndrome Pathophysiology Acute_respiratory_distress_syndrome > Pathophysiology Of these, the pathology most commonly associated with ARDS is DAD, which is characterized by a diffuse inflammation of lung tissue. The triggering insult to the tissue usually results in an initial release of chemical signals and other inflammatory mediators secreted by local epithelial and endothelial cells.Neutrophils and some T-lymphocytes quickly migrate into the inflamed lung tissue and contribute in the amplification of the phenomenon. The typical histological presentation involves diffuse alveolar damage and hyaline membrane formation in alveolar walls. Although the triggering mechanisms are not completely understood, recent research has examined the role of inflammation and mechanical stress.One research group has reported that broncho-alveolar lavage fluid in later-stage ARDS often contains trichomonads, in an amoeboid form (i.e. lacking their characteristic flagellum) which makes them difficult to identify under the microscope.
Language pedagogy Audio-lingual method Language_pedagogy > Structural methods > Audio-lingual method Julian Dakin, in 'The Language Laboratory and Language Learning' (Longman 1973), coined the phrase 'meaningless drills' to describe this kind of pattern practice, which others have also described as "mimicry-memorization." 5. There was a vocabulary list, sometimes with translations to the mother tongue.
Balsa wood bridge Testing Balsa_wood_bridge > Testing Bridges are usually tested by applying a downward force on the bridge. How and where the force is applied varies from one contest to the next. There are two common methods of applying the test force to the bridge: By hanging a container (such as a trash can) from the bridge and loading known weights into the container until the bridge breaks. The tester could also slowly add water or sand to the container until the bridge breaks and then weigh the container, providing a more accurate way to find the breaking force.
Windmill Machinery Windmill > Mechanics > Machinery It has the brake around the outside of the rim and teeth in the side of the rim which drives the horizontal gearwheel called wallower on the top end of the vertical upright shaft. In grist mills, the great spur wheel, lower down the upright shaft, drives one or more stone nuts on the shafts driving each millstone. Post mills sometimes have a head and/or tail wheel driving the stone nuts directly, instead of the spur gear arrangement.
DNS root zone Initialization of DNS service DNS_root_zone > Initialization of DNS service To avoid this circular dependency, the address of at least one root server must be known for bootstrapping access to the DNS. For this purpose, operating systems or DNS servers or resolver software packages typically include a file with all addresses of the DNS root servers. Even if the IP addresses of some root servers change, at least one is needed to retrieve the current list of all name servers. This address file is called named.cache in the BIND name server reference implementation. The current official version is distributed by ICANN's InterNIC.With the address of a single functioning root server, all other DNS information may be discovered recursively, and information about any domain name may be found.
Quantum process Summary Quantum_process In quantum mechanics, a quantum process is a somewhat ambiguous term which usually refers to the time evolution of an (open) quantum system. Under very general assumptions, a quantum process is described by the quantum operation formalism (also known as a quantum dynamical map), which is a linear, trace-preserving, and completely positive map from the set of density matrices to itself. For instance, in quantum process tomography, the unknown quantum process is assumed to be a quantum operation. However, not all quantum processes can be captured within the quantum operation formalism; in principle, the density matrix of a quantum system can undergo completely arbitrary time evolution.
DYA framework Quality attributes for communication DYA_framework > DYA infrastructure > The DYA infrastructure architecture process > Quality attributes for communication These must serve as a basis for further reconciliation and harmonization of definitions within the architectural process. Infrastructure architecture provides its own set of quality attributes, alongside the specific quality attributes of the business and information architectures. Apart from the quality attributes, there are two major restrictions that influence the potential direction of a solution, namely cost and time.
AVN-322 Summary AVN-322 AVN-322 is a 5-hydroxytryptamine subtype 6 receptor antagonist manufactured by Avineuro Pharmaceuticals Inc. that could potentially be used to combat Alzheimer's disease and schizophrenia. AVN-322 also reverses the negative effects of scopolamine and MK-80.The compound is a sister drug to AVN-101 and AVN-211, two similar compounds under trial for treating Alzheimer's. Phase I trials for the drug were initiated in 2009 by Avineuro, and completed in the spring of 2010.
Induction generator Excitation Induction_generator > Principle of operation > Excitation An induction motor requires an externally supplied current to the stator windings in order to induce a current in the rotor. Because the current in an inductor is integral of the voltage with respect to time, for a sinusoidal voltage waveform the current lags the voltage by 90°, and the induction motor always consumes reactive power, regardless of whether it is consuming electrical power and delivering mechanical power as a motor or consuming mechanical power and delivering electrical power to the system. A source of excitation current for magnetizing flux (reactive power) for the stator is still required, to induce rotor current. This can be supplied from the electrical grid or, once it starts producing power, from a capacitive reactance .
Ribosomal RNAs Subunits and associated ribosomal RNA Ribosomal_RNAs > Subunits and associated ribosomal RNA The sedimentation rate of each subunit is affected by its shape, as well as by its mass. The nt units can be added as these represent the integer number of units in the linear rRNA polymers (for example, the total length of the human rRNA = 7216 nt). Gene clusters coding for rRNA are commonly called "ribosomal DNA" or rDNA (note that the term seems to imply that ribosomes contain DNA, which is not the case).
Bayes's Theorem Bayes' rule in odds form Bayes_Theorem > Forms > Bayes' rule in odds form So after receiving a positive test result, the posterior odds of actually having the disease becomes 1:1, which means that the posterior probability of having the disease is 50%. If a second test is performed in serial testing, and that also turns out to be positive, then the posterior odds of actually having the disease becomes 10:1, which means a posterior probability of about 90.91%. The negative Bayes factor can be calculated to be 91%/(100%-90%)=9.1, so if the second test turns out to be negative, then the posterior odds of actually having the disease is 1:9.1, which means a posterior probability of about 9.9%.
Control engineer Overview Control_system_engineering > Overview In most cases, control engineers utilize feedback when designing control systems. This is often accomplished using a PID controller system. For example, in an automobile with cruise control the vehicle's speed is continuously monitored and fed back to the system, which adjusts the motor's torque accordingly.
Architectural models Purpose Building_model > Purpose Once a building is finished, the model is sometimes featured in a common area of the building. Types of models include: Exterior models are models of buildings that usually include some landscaping or civic spaces around the building. Interior models are models showing interior space planning, finishes, colors, furniture, and beautification.
Turing's proof Summary of the first proof Turing's_proof > Summary of the proofs > Summary of the first proof Turing then describes (rather loosely) the algorithm (method) to be followed by a machine he calls H. Machine H contains within it the decision-machine D (thus D is a “subroutine” of H). Machine H’s algorithm is expressed in H’s table of instructions, or perhaps in H’s Standard Description on tape and united with the universal machine U; Turing does not specify this. In the course of describing universal machine U, Turing has demonstrated that a machine’s S.D (string of letters similar to a “program”) can be converted to an integer (base 8) and vice versa.
Database modelling Relational model Database_modelling > Relational model The basic data structure of the relational model is the table, where information about a particular entity (say, an employee) is represented in rows (also called tuples) and columns. Thus, the "relation" in "relational database" refers to the various tables in the database; a relation is a set of tuples. The columns enumerate the various attributes of the entity (the employee's name, address or phone number, for example), and a row is an actual instance of the entity (a specific employee) that is represented by the relation.
Glossary of civil engineering B Glossary_of_civil_engineering > B Beer–Lambert law belt belt friction bending benefit–cost analysis bending momentThe reaction induced in a structural element when an external force or moment is applied to the element causing the element to bend. Bernoulli differential equation Bernoulli's equation Bernoulli's principle In fluid dynamics, Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy.
Small arm Bolt action Small_arms > Action > Manual > Bolt action Bolt action is a repeating (and rarely single-shot) action that is operated by directly manipulating the bolt via a bolt handle. The bolt is unlocked from the receiver, then pulled back to open the breech, ejecting a cartridge, and cocking the striker and engaging it against the sear; when the bolt is returned to the forward position, a new cartridge, if loaded, is pushed out of the magazine and into the barrel chamber, and the breech is re-locked. Two designs of bolt action exist: rotating bolt, where the bolt must be axially rotated to unlock and lock the receiver; and straight pull, which does not require the bolt to be rotated, simplifying the bolt action mechanism and allowing for a greater rate of fire.
Experimental system Summary Experimental_system In scientific research, an experimental system is the physical, technical and procedural basis for an experiment or series of experiments. Historian of science Hans-Jörg Rheinberger defines an experimental system as: "A basic unit of experimental activity combining local, technical, instrumental, institutional, social, and epistemic aspects." Scientists (particularly laboratory biologists) and historians and philosophers of biology have pointed to the development and spread of successful experimental systems, such as those based on popular model organism or scientific apparatus, as key elements in the history of science, particularly since the early 20th century. The choice of an appropriate experimental system is often seen as critical for a scientist's long-term success, as experimental systems can be very productive for some kinds of questions and less productive for others, acquiring a sort of momentum that takes research in unpredicted directions.A successful experimental system must be stable and reproducible enough for scientists to make sense of the system's behavior, but variable and unpredictable enough that it can produce useful results.
Global concurrency control Database transaction and the ACID rules Concurrency_control > Concurrency control in databases > Database transaction and the ACID rules Moreover, usually (depending on concurrency control method) the effects of an incomplete transaction are not even visible to another transaction. Providing isolation is the main goal of concurrency control. Durability - Effects of successful (committed) transactions must persist through crashes (typically by recording the transaction's effects and its commit event in a non-volatile memory).The concept of atomic transaction has been extended during the years to what has become Business transactions which actually implement types of Workflow and are not atomic. However also such enhanced transactions typically utilize atomic transactions as components.
TI-89 Summary TI-89_series The TI-89 and the TI-89 Titanium are graphing calculators developed by Texas Instruments (TI). They are differentiated from most other TI graphing calculators by their computer algebra system, which allows symbolic manipulation of algebraic expressions—equations can be solved in terms of variables, whereas the TI-83/84 series can only give a numeric result.
GNU Units Version history GNU_Units > History > Version history Version 2.0, released on 2 July 2012, added the ability to convert to sums of units, such as hours and minutes or feet and inches. In addition, this release added support for UTF-8 encoding. Provision for locale-specific unit definitions was added.
Bayesian analysis General formulation Bayesian_analysis > Inference over exclusive and exhaustive possibilities > General formulation Suppose that the process is observed to generate E ∈ { E n } {\displaystyle E\in \{E_{n}\}} . For each M ∈ { M m } {\displaystyle M\in \{M_{m}\}} , the prior P ( M ) {\displaystyle P(M)} is updated to the posterior P ( M ∣ E ) {\displaystyle P(M\mid E)} . From Bayes' theorem: Upon observation of further evidence, this procedure may be repeated.
Erwin Schrödinger Later years Erwin_Schrödinger > Biography > Later years According to James D. Watson's memoir, DNA, the Secret of Life, Schrödinger's book gave Watson the inspiration to research the gene, which led to the discovery of the DNA double helix structure in 1953. Similarly, Francis Crick, in his autobiographical book What Mad Pursuit, described how he was influenced by Schrödinger's speculations about how genetic information might be stored in molecules.Schrödinger stayed in Dublin until retiring in 1955. A manuscript "Fragment from an unpublished dialogue of Galileo" from this time recently resurfaced at The King's Hospital boarding school, Dublin after it was written for the School's 1955 edition of their Blue Coat to celebrate his leaving of Dublin to take up his appointment as Chair of Physics at the University of Vienna.In 1956, he returned to Vienna (chair ad personam). At an important lecture during the World Energy Conference he refused to speak on nuclear energy because of his scepticism about it and gave a philosophical lecture instead. During this period, Schrödinger turned from mainstream quantum mechanics' definition of wave–particle duality and promoted the wave idea alone, causing much controversy.
Heat death of the Universe Opposing views Heat_death_of_the_Universe > Opposing views Max Planck wrote that the phrase "entropy of the universe" has no meaning because it admits of no accurate definition. In 2008, Walter Grandy wrote: "It is rather presumptuous to speak of the entropy of a universe about which we still understand so little, and we wonder how one might define thermodynamic entropy for a universe and its major constituents that have never been in equilibrium in their entire existence." According to Tisza: "If an isolated system is not in equilibrium, we cannot associate an entropy with it." Buchdahl writes of "the entirely unjustifiable assumption that the universe can be treated as a closed thermodynamic system".
RNA-directed DNA methylation Development and reproduction RNA-directed_DNA_methylation > Biological functions > Development and reproduction The loss of DNA methylation and associated late-flowering phenotype can be stably transmitted to progeny. Since the demethylated fwa allele leads to a stable, heritable change in the expression of FWA without any change to the DNA sequence, it is a classic example of an epiallele.
Fixed-point theorems in infinite-dimensional spaces Summary Fixed_point_theorems_in_infinite-dimensional_spaces One way in which fixed-point theorems of this kind have had a larger influence on mathematics as a whole has been that one approach is to try to carry over methods of algebraic topology, first proved for finite simplicial complexes, to spaces of infinite dimension. For example, the research of Jean Leray who founded sheaf theory came out of efforts to extend Schauder's work. Schauder fixed-point theorem: Let C be a nonempty closed convex subset of a Banach space V. If f: C → C is continuous with a compact image, then f has a fixed point.
Human memory Genetic underpinnings Human_memory > Genetics > Genetic underpinnings PKMζ maintains the activity-dependent enhancement of synaptic strength and inhibiting PKMζ erases established long-term memories, without affecting short-term memory or, once the inhibitor is eliminated, the ability to encode and store new long-term memories is restored. Also, BDNF is important for the persistence of long-term memories.The long-term stabilization of synaptic changes is also determined by a parallel increase of pre- and postsynaptic structures such as axonal bouton, dendritic spine and postsynaptic density. On the molecular level, an increase of the postsynaptic scaffolding proteins PSD-95 and HOMER1c has been shown to correlate with the stabilization of synaptic enlargement. The cAMP response element-binding protein (CREB) is a transcription factor which is believed to be important in consolidating short-term to long-term memories, and which is believed to be downregulated in Alzheimer's disease.
27 (number) Summary 27_(number) 27 (twenty-seven; Roman numeral XXVII) is the natural number following 26 and preceding 28.
Symmetry transformation In literature Symmetry_transformation > In the arts > In literature Symmetry can be found in various forms in literature, a simple example being the palindrome where a brief text reads the same forwards or backwards. Stories may have a symmetrical structure, such as the rise and fall pattern of Beowulf.
Dirac mass Lagrangian formulation Dirac_equation > Mathematical formulation > Lagrangian formulation Gauging this field theory by changing the symmetry to a local, spacetime point dependent one gives gauge symmetry (really, gauge redundancy). The resultant theory is quantum electrodynamics or QED. See below for a more detailed discussion.
Treeline outliner File format Treeline_outliner > File formats > File format TreeLine uses a simple XML syntax to store data, with a .trl extension.
Nucleophilic acyl substitution Acid halides Nucleophilic_acyl_substitution > Reactions of acyl derivatives > Acid halides The Weinreb ketone synthesis can also be used to convert acid halides to ketones. In this reaction, the acid halide is first converted to an N–methoxy–N–methylamide, known as a Weinreb amide. When a carbon nucleophile – such as a Grignard or organolithium reagent – adds to a Weinreb amide, the metal is chelated by the carbonyl and N–methoxy oxygens, preventing further nucleophilic additions.In the Friedel–Crafts acylation, acid halides act as electrophiles for electrophilic aromatic substitution. A Lewis acid – such as zinc chloride (ZnCl2), iron(III) chloride (FeCl3), or aluminum chloride (AlCl3) – coordinates to the halogen on the acid halide, activating the compound towards nucleophilic attack by an activated aromatic ring. For especially electron-rich aromatic rings, the reaction will proceed without a Lewis acid.
Metal ligand multiple bond Further reading (specialized literature) Pi-donor_ligands > Further reading (specialized literature) doi:10.1021/ja01557a001 Rohde,J; In,J. ; Lim, M.H. ; Brennessel, W.W.
Tomasulo algorithm Exceptions Tomasulo's_algorithm > Implementation concepts > Exceptions Practically speaking, there may be exceptions for which not enough status information about an exception is available, in which case the processor may raise a special exception, called an "imprecise" exception. Imprecise exceptions cannot occur in in-order implementations, as processor state is changed only in program order (see RISC Pipeline Exceptions). Programs that experience "precise" exceptions, where the specific instruction that took the exception can be determined, can restart or re-execute at the point of the exception. However, those that experience "imprecise" exceptions generally cannot restart or re-execute, as the system cannot determine the specific instruction that took the exception.
Testicular carcinoma Staging Testicular_cancer > Diagnosis > Staging After removal, the testicle is fixed with Bouin's solution because it better conserves some morphological details such as nuclear conformation. Then the testicular tumor is staged by a pathologist according to the TNM Classification of Malignant Tumors as published in the AJCC Cancer Staging Manual. Testicular cancer is categorized as being in one of three stages (which have subclassifications). The size of the tumor in the testis is irrelevant to staging.
Magnetotropism Summary Magnetotropism Magnetotropism is the movement or plant growth in response to the stimulus provided by the magnetic field in plants (specifically agricultural plants) around the world. As a natural environmental factor in the Earth, variations of magnetic field level causes many biological effects, including germination rate, flowering time, photosynthesis, biomass accumulation, activation of cryptochrome, and shoot growth.
Automatic guided vehicle Traffic control Automatic_guided_vehicle > Traffic control Flexible manufacturing systems containing more than one AGV may require it to have traffic control so the AGV's will not run into one another. Traffic control can be carried out locally or by software running on a fixed computer elsewhere in the facility. Local methods include zone control, forward sensing control, and combination control. Each method has its advantages and disadvantages.
Reproductive strategy Mitosis and meiosis Reproduction > Sexual > Mitosis and meiosis Mitosis and meiosis are types of cell division. Mitosis occurs in somatic cells, while meiosis occurs in gametes. Mitosis The resultant number of cells in mitosis is twice the number of original cells. The number of chromosomes in the offspring cells is the same as that of the parent cell.
Improper integrals Summary Improper_integrals If a regular definite integral (which may retronymically be called a proper integral) is worked out as if it is improper, the same answer will result. In the simplest case of a real-valued function of a single variable integrated in the sense of Riemann (or Darboux) over a single interval, improper integrals may be in any of the following forms: ∫ a ∞ f ( x ) d x {\displaystyle \int _{a}^{\infty }f(x)\,dx} ∫ − ∞ b f ( x ) d x {\displaystyle \int _{-\infty }^{b}f(x)\,dx} ∫ − ∞ ∞ f ( x ) d x {\displaystyle \int _{-\infty }^{\infty }f(x)\,dx} ∫ a b f ( x ) d x {\displaystyle \int _{a}^{b}f(x)\,dx} , where f ( x ) {\displaystyle f(x)} is undefined or discontinuous somewhere on {\displaystyle } The first three forms are improper because the integrals are taken over an unbounded interval. (They may be improper for other reasons, as well, as explained below.)
Dental sealant Background Dental_sealant > Background These molar teeth are considered the most susceptible teeth to dental caries due to the anatomy of the chewing surfaces of these teeth, which inhibits protection from saliva and fluoride and instead favours plaque accumulation. This approach facilitates prevention and early intervention, in order to prevent or stop the dental caries process before it reaches the ends stage of the disease, which is also known as the "hole" or cavitation of a tooth. Once the tooth is cavitated, it requires a dental restoration in order to repair the damage, which emphasizes the importance of prevention in preserving teeth for a lifetime of chewing.
Dispersing prism Grisms (grating prisms) Triangular_prism_(optics) > Grisms (grating prisms) A diffraction grating may be ruled onto one face of a prism to form an element called a "grism". Spectrographs are extensively used in astronomy to observe the spectra of stars and other astronomical objects. Insertion of a grism in the collimated beam of an astronomical imager transforms that camera into a spectrometer, since the beam still continues in approximately the same direction when passing through it. The deflection of the prism is constrained to exactly cancel the deflection due to the diffraction grating at the spectrometer's central wavelength.
Cardiolipin Other functions Cardiolipin > Functions > Other functions Cholesterol translocation from outer to the inner mitochondrial membrane Activates mitochondrial cholesterol side-chain cleavage Import protein into mitochondrial matrix Anticoagulant function Modulates α-synuclein - malfunction of this process is thought to be a cause of Parkinson's disease.
Bivalent (genetics) Summary Chromosome_pair In most organisms, each replicated chromosome (composed of two identical sisters chromatid) elicits formation of DNA double-strand breaks during the leptotene phase. These breaks are repaired by homologous recombination, that uses the homologous chromosome as a template for repair. The search for the homologous target, helped by numerous proteins collectively referred as the synaptonemal complex, cause the two homologs to pair, between the leptotene and the pachytene phases of meiosis I.
S1C reactor Summary S1C_reactor The S1C reactor was a prototype naval reactor designed for the United States Navy to provide electricity generation and propulsion on warships. The S1C designation stands for: S = Submarine platform 1 = First generation core designed by the contractor C = Combustion Engineering (C-E) was the contracted designer
Relativistic dynamics Invariant Evolution Parameter Concept Relativistic_dynamics > Invariant Evolution Parameter Concept Einstein's view of time requires a physical equivalence between coordinate time and coordinate space. In this view, time should be a reversible coordinate in the same manner as space. Particles moving backward in time are often used to display antiparticles in Feynman-diagrams, but they are not thought of as really moving backward in time usually it is done to simplify notation.
Language pedagogy The series method Language_pedagogy > Interactive methods > The series method He also found that people will memorize events in a logical sequence, even if they are not presented in that order. He discovered a second insight into memory called "incubation".
Keplers laws Planetary acceleration Kepler's_Laws > Planetary acceleration Isaac Newton computed in his Philosophiæ Naturalis Principia Mathematica the acceleration of a planet moving according to Kepler's first and second laws. The direction of the acceleration is towards the Sun. The magnitude of the acceleration is inversely proportional to the square of the planet's distance from the Sun (the inverse square law).This implies that the Sun may be the physical cause of the acceleration of planets. However, Newton states in his Principia that he considers forces from a mathematical point of view, not a physical, thereby taking an instrumentalist view.
Model Predictive Control Overview Model_Predictive_Control > Overview In some cases, the process variables can be transformed before and/or after the linear MPC model to reduce the nonlinearity. The process can be controlled with nonlinear MPC that uses a nonlinear model directly in the control application. The nonlinear model may be in the form of an empirical data fit (e.g. artificial neural networks) or a high-fidelity dynamic model based on fundamental mass and energy balances.
Nucleosome H3 and H4 Nucleosome_core_particle > Nucleosome assembly in vivo > H3 and H4 The old H3 and H4 proteins retain their chemical modifications which contributes to the passing down of the epigenetic signature. The newly synthesized H3 and H4 proteins are gradually acetylated at different lysine residues as part of the chromatin maturation process. It is also thought that the old H3 and H4 proteins in the new nucleosomes recruit histone modifying enzymes that mark the new histones, contributing to epigenetic memory.
Glossary of probability and statistics L Glossary_of_probability_and_statistics > L L-moment law of large numbers (LLN) A theorem according to which the average of the results obtained from performing the same experiment a large number of times should be close to the experiment's expected value, and tends to become closer to the expected value as more trials are performed. The law suggests that a sufficiently large number of trials is necessary for the results of any experiment to be considered reliable, and by extension that performing only a small number of trials may produce an incomplete or misleading interpretation of the experiment's outcomes. likelihood function A conditional probability function considered a function of its second argument with its first argument held fixed. For example, imagine pulling a numbered ball with a number k from a bag of n balls, numbered 1 to n; a likelihood function for the random variable N could be described as the probability of pulling k given that there are n balls: the likelihood will be 1/n for n greater than or equal to k, and 0 for n smaller than k. Unlike a probability distribution function, this likelihood function will not sum up to 1 on the sample space. loss function likelihood-ratio test
Diabetic foot infection Peripheral artery disease Diabetic_foot_infection > Mechanism > Peripheral artery disease Metabolic changes in diabetes, including hyperglycemia, lead to increased likelihood of -hyperlipidemia and developing atherosclerosis. In diabetes, this atherosclerosis is preferentially distributed to the posterior and anterior tibial arteries, decreasing perfusion to the lower extremities. This may lead to loss of skin integrity, ischemic ulcers, and gangrene. Infection may vary in the depth of tissue to which it extends.
Blue hydrogen Thermochemical cycle Hydrogen_production > From water > Thermochemical cycle The sulfur and iodine used in the process are recovered and reused, and not consumed by the process. The cycle can be performed with any source of very high temperatures, approximately 950 °C, such as by Concentrating solar power systems (CSP) and is regarded as being well suited to the production of hydrogen by high-temperature nuclear reactors, and as such, is being studied in the High-temperature engineering test reactor in Japan. There are other hybrid cycles that use both high temperatures and some electricity, such as the Copper–chlorine cycle, it is classified as a hybrid thermochemical cycle because it uses an electrochemical reaction in one of the reaction steps, it operates at 530 °C and has an efficiency of 43 percent.
Mir-616 microRNA precursor family Summary Mir-616_microRNA_precursor_family mir-616 microRNA is a short non-coding RNA molecule belonging both to the family of microRNAs and to that of small interfering RNAs (siRNAs). MicroRNAs function to regulate the expression levels of other genes by several mechanisms, whilst siRNAs are involved primarily with the RNA interference (RNAi) pathway. miR-616 has been found to induce the specifically androgen-independent growth of prostate cancer cells.
Histone modification Link between cell-cycle control and synthesis Histone_modification > Synthesis > Link between cell-cycle control and synthesis Nuclear protein Ataxia-Telangiectasia (NPAT), also known as nuclear protein coactivator of histone transcription, is a transcription factor which activates histone gene transcription on chromosomes 1 and 6 of human cells. NPAT is also a substrate of cyclin E-Cdk2, which is required for the transition between G1 phase and S phase. NPAT activates histone gene expression only after it has been phosphorylated by the G1/S-Cdk cyclin E-Cdk2 in early S phase. This shows an important regulatory link between cell-cycle control and histone synthesis.
Models of scientific inquiry Logical empiricism Scientific_explanation > Accounts of scientific inquiry > Logical empiricism Depending on a number of additional qualifications, an explanation may be ranked on a scale from potential to true. Not all explanations in science are of the D-N type, however. An inductive-statistical (I-S) explanation accounts for an occurrence by subsuming it under statistical laws, rather than categorical or universal laws, and the mode of subsumption is itself inductive instead of deductive.
Column family Summary Column_family A column family is a database object that contains columns of related data. It is a tuple (pair) that consists of a key–value pair, where the key is mapped to a value that is a set of columns. In analogy with relational databases, a column family is as a "table", each key-value pair being a "row".
Geology Geological development of an area Geology > Geological development of an area These structural regimes broadly relate to convergent boundaries, divergent boundaries, and transform boundaries, respectively, between tectonic plates. When rock units are placed under horizontal compression, they shorten and become thicker. Because rock units, other than muds, do not significantly change in volume, this is accomplished in two primary ways: through faulting and folding.
Refraction index History Complex_refractive_index > History Hauksbee, who called it the "ratio of refraction", wrote it as a ratio with a fixed numerator, like "10000 to 7451.9" (for urine). Hutton wrote it as a ratio with a fixed denominator, like 1.3358 to 1 (water).Young did not use a symbol for the index of refraction, in 1807. In the later years, others started using different symbols: n, m, and µ. The symbol n gradually prevailed.
Regulation of gastric function Chemical activation Cephalic_phase > Phases > Gastric phase > Chemical activation ACh is secreted by parasympathetic nerve fibers of both the short and long reflex ,.ml; pathways. Histamine is a paracrine secretion from the enteroendocrine cells in the gastric glands. Gastrin is a hormone produced by enteroendocrine G cells in the pyloric glands.All three of these stimulate parietal cells to secrete hydrochloric acid and intrinsic factor. The chief cells secrete pepsinogen in response to gastrin and especially Ach, and ACh also stimulates mucus secretion.
Engine power Summary Engine_power Engine power is the power that an engine can put out. It can be expressed in power units, most commonly kilowatt, pferdestärke (metric horsepower), or horsepower. In terms of internal combustion engines, the engine power usually describes the rated power, which is a power output that the engine can maintain over a long period of time according to a certain testing method, for example ISO 1585. In general though, an internal combustion engine has a power take-off shaft (the crankshaft), therefore, the rule for shaft power applies to internal combustion engines: Engine power is the product of the engine torque and the crankshaft's angular velocity.
IDEF5 Diagram types IDEF5 > IDEF5 Building blocks > Diagram types Composition Schematics: Composition schematics serve as mechanisms to represent graphically the "part-of" relation that is so common among components of an ontology. Relation Schematics: Relation schematics allow ontology developers to visualize and understand relations among kinds in a domain, and can also be used to capture and display relations between first-order relations. Object State Schematics: Because there is no clean division between information about kinds and states and information about processes, the IDEF5 schematic language enables modelers to express fairly detailed object-centered process information (i.e., information about kinds of objects and the various states they can be in relative to certain processes). Diagrams built from these constructs are known as Object-State Schematics.
Differential item functioning Summary Differential_item_functioning Differential item functioning (DIF) is a statistical characteristic of an item that shows the extent to which the item might be measuring different abilities for members of separate subgroups. Average item scores for subgroups having the same overall score on the test are compared to determine whether the item is measuring in essentially the same way for all subgroups. The presence of DIF requires review and judgment, and it does not necessarily indicate the presence of bias.
Bernhard Riemann Writings Bernhard_Riemann > Writings PDF on Wikimedia Commons. On archive.org: Riemann, Bernhard (1901). Weber, Heinrich Martin (ed.).
Gale (crater) Geology Gale_(crater) > Geology Evidence of fluvial activity was observed early on in the mission at the Shaler outcrop (first observed on Sol 120, investigated extensively between Sols 309-324). Observations made by the rover Curiosity at the Pahrump Hills strongly support the lake hypothesis: sedimentary facies including sub mm-scale horizontally-laminated mudstones, with interbedded fluvial crossbeds are representative of sediments which accumulate in lakes, or on the margins of lakes which grow and contract in response to lake-level. These lake-bed mudstones are referred to as the Murray Formation, and form a significant amount of the Mount Sharp group.