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Raman spectrum Enhanced (or near-field) Raman spectroscopy Raman_studies > Variants > Enhanced (or near-field) Raman spectroscopy This effect was originally observed by Martin Fleischmann but the prevailing explanation was proposed by Van Duyne in 1977. A comprehensive theory of the effect was given by Lombardi and Birke. Surface-enhanced resonance Raman spectroscopy (SERRS) – A combination of SERS and resonance Raman spectroscopy that uses proximity to a surface to increase Raman intensity, and excitation wavelength matched to the maximum absorbance of the molecule being analysed.
Combined central and peripheral demyelination Treatment Chronic_inflammatory_demyelinating_polyneuropathy > Treatment First-line treatment for CIDP is currently intravenous immunoglobulin and other treatments include corticosteroids (e.g., prednisone), and plasmapheresis (plasma exchange) which may be prescribed alone or in combination with an immunosuppressant drug. Recent controlled studies show subcutaneous immunoglobulin appears to be as effective for CIDP treatment as intravenous immunoglobulin in most patients, and with fewer systemic side effects.Intravenous immunoglobulin and plasmapheresis have proven benefit in randomized, double-blind, placebo-controlled trials. Despite less definitive published evidence of efficacy, corticosteroids are considered standard therapies because of their long history of use and cost effectiveness. Intravenous immunoglobulin is probably the first-line CIDP treatment, but is extremely expensive.
Aerobic respiration Fermentation Plant_respiration > Fermentation Lactate formation is catalyzed by lactate dehydrogenase in a reversible reaction. Lactate can also be used as an indirect precursor for liver glycogen.
J. M. E. McTaggart McTaggart's paradox J._M._E._McTaggart > McTaggart's paradox McTaggart is best known today for his attempt to prove that our concept of time involves a contradiction, and that therefore reality cannot be temporal. It follows that our perception of time is an illusion, and that time itself is merely ideal. His argument for this point is popularly known as McTaggart's paradox.
Parabolic Flight Operating principles Reduced_gravity_aircraft > Operating principles During this time the aircraft does not exert any ground reaction force on its contents, causing the sensation of weightlessness. Initially, the aircraft climbs with a pitch angle of 45 degrees using engine thrust and elevator controls. The sensation of weightlessness is achieved by reducing thrust and lowering the nose to maintain a neutral, or "zero lift", configuration such that the aircraft follows a ballistic trajectory, with engine thrust exactly compensating for drag.
Java keywords List of Java keywords Java_keywords > List of Java keywords If the superclass is not explicitly specified, the superclass is implicitly Object. The class keyword can also be used in the form Class.class to get a Class object without needing an instance of that class. For example, String.class can be used instead of doing new String().getClass().const Unused but reserved.continue Used to resume program execution at the end of the current loop body.
Human genome sequence map Genes for noncoding RNA (ncRNA) Human_genome_sequence > Noncoding DNA (ncDNA) > Genes for noncoding RNA (ncRNA) Noncoding RNA molecules play many essential roles in cells, especially in the many reactions of protein synthesis and RNA processing. Noncoding RNA include tRNA, ribosomal RNA, microRNA, snRNA and other non-coding RNA genes including about 60,000 long non-coding RNAs (lncRNAs). Although the number of reported lncRNA genes continues to rise and the exact number in the human genome is yet to be defined, many of them are argued to be non-functional.Many ncRNAs are critical elements in gene regulation and expression. Noncoding RNA also contributes to epigenetics, transcription, RNA splicing, and the translational machinery. The role of RNA in genetic regulation and disease offers a new potential level of unexplored genomic complexity.
Nervous system network models Modular models of brain function Nervous_system_network_models > Nervous system models > Modular models of brain function The modular approach is intended to build cognitive models and is, in complexity, between the anatomically defined brain regions (defined as macrolevel in brain connectivity) and the computational model at the neuron level. There are three views of modules for modeling. They are (1) modules for brain structures, (2) modules as schemas, and (3) modules as interfaces.
Crowd work In product design Crowdsourcing_creative_work > Applications > In product design LEGO allows users to work on new product designs while conducting requirements testing. Any user can provide a design for a product, and other users can vote on the product. Once the submitted product has received 10,000 votes, it will be formally reviewed in stages and go into production with no impediments such as legal flaws identified. The creator receives royalties from the net income.
Optimal job scheduling Other variants Optimal_job_scheduling > Other variants All variants surveyed above are deterministic in that all data is known to the planner. There are also stochastic variants, in which the data is not known in advance, or can perturb randomly. In a load balancing game, each job belongs to a strategic agent, who can decide where to schedule his job. The Nash equilibrium in this game may not be optimal. Aumann and Dombb assess the inefficiency of equilibrium in several load-balancing games.
Discrete Mathematics Set theory Discrete_math > Topics in discrete mathematics > Set theory Set theory is the branch of mathematics that studies sets, which are collections of objects, such as {blue, white, red} or the (infinite) set of all prime numbers. Partially ordered sets and sets with other relations have applications in several areas. In discrete mathematics, countable sets (including finite sets) are the main focus. The beginning of set theory as a branch of mathematics is usually marked by Georg Cantor's work distinguishing between different kinds of infinite set, motivated by the study of trigonometric series, and further development of the theory of infinite sets is outside the scope of discrete mathematics. Indeed, contemporary work in descriptive set theory makes extensive use of traditional continuous mathematics.
Acute liver disease Metabolic derangements Fulminant_liver_failure > Signs and symptoms > Metabolic derangements Hyponatraemia is an almost universal finding due to water retention and a shift in intracellular sodium transport from inhibition of Na/K ATPase. Hypoglycaemia (due to depleted hepatic glycogen store and hyperinsulinaemia), hypokalaemia, hypophosphataemia and metabolic alkalosis are often present, independent of renal function. Lactic acidosis occurs predominantly in paracetamol (also known as acetaminophen) overdose.
Chemical dependency Vaccines Drug_dependence > Treatment and issues > Medicinal approach > Vaccines TA-CD is an active vaccine developed by the Xenova Group which is used to negate the effects of cocaine, making it suitable for use in treatment of addiction. It is created by combining norcocaine with inactivated cholera toxin. TA-NIC is a proprietary vaccine in development similar to TA-CD but being used to create human anti-nicotine antibodies in a person to destroy nicotine in the human body so that it is no longer effective.
Amazon EMR Architecture Apache_Hadoop > Architecture The master node consists of a Job Tracker, Task Tracker, NameNode, and DataNode. A slave or worker node acts as both a DataNode and TaskTracker, though it is possible to have data-only and compute-only worker nodes. These are normally used only in nonstandard applications.Hadoop requires the Java Runtime Environment (JRE) 1.6 or higher.
Hammond postulate Kinetics and the Bell–Evans–Polanyi principle Hammond_postulate > Kinetics and the Bell–Evans–Polanyi principle Although two transition states occur during a SN1 reaction (dissociation of the leaving group and then attack by the nucleophile), the dissociation of the leaving group is almost always the rate-determining step. Hence, the activation energy and therefore rate of the reaction will depend only upon the dissociation step. First, consider the reaction at secondary and tertiary carbons.
Inverse kinematics Robotics Inverse_kinematics > Robotics Inverse kinematics transforms the motion plan into joint actuator trajectories for the robot. Similar formulas determine the positions of the skeleton of an animated character that is to move in a particular way in a film, or of a vehicle such as a car or boat containing the camera which is shooting a scene of a film. Once a vehicle's motions are known, they can be used to determine the constantly-changing viewpoint for computer-generated imagery of objects in the landscape such as buildings, so that these objects change in perspective while themselves not appearing to move as the vehicle-borne camera goes past them.
Study of animal locomotion Analyzing kinematics across steps Study_of_animal_locomotion > Quantifying locomotion > Walking > Analyzing kinematics across steps It is often useful to compare or pool step data. One difficulty in this pursuit is the variable length of steps both within and between legs. There are many ways to align steps, the following are a few useful methods.
Community of practice Compared to functional or project teams Community_of_practice > Types > Compared to functional or project teams Collaboration constellations differ in various ways. Some are under organizational control (e.g., teams, see below) others, like CoPs, are self-organized or under the control of individuals. For examples of how these and other collaboration types vary in terms of their temporal or boundary focus and the basis of their members' relationships, see Kietzmann et al. (2013). A project team differs from a community of practice in several significant ways.
Mark and recapture Capture probability Mark_and_recapture > Capture probability The capture probability refers to the probability of a detecting an individual animal or person of interest, and has been used in both ecology and epidemiology for detecting animal or human diseases, respectively. The capture probability is often defined as a two-variable model, in which f is defined as the fraction of a finite resource devoted to detecting the animal or person of interest from a high risk sector of an animal or human population, and q is the frequency of time that the problem (e.g., an animal disease) occurs in the high-risk versus the low-risk sector. For example, an application of the model in the 1920s was to detect typhoid carriers in London, who were either arriving from zones with high rates of tuberculosis (probability q that a passenger with the disease came from such an area, where q>0.5), or low rates (probability 1−q). It was posited that only 5 out of every 100 of the travelers could be detected, and 10 out of every 100 were from the high risk area.
Biological rhythms The subject Chronobiology > The subject Many other important cycles are also studied, including: Infradian rhythms, which are cycles longer than a day. Examples include circannual or annual cycles that govern migration or reproduction cycles in many plants and animals, or the human menstrual cycle. Ultradian rhythms, which are cycles shorter than 24 hours, such as the 90-minute REM cycle, the 4-hour nasal cycle, or the 3-hour cycle of growth hormone production.
Congenital hypopituitarism Complications Congenital_hypopituitarism > Signs and symptoms > Complications Several hormone deficiencies associated with hypopituitarism may lead to secondary diseases. For instance, growth hormone deficiency is associated with obesity, raised cholesterol and the metabolic syndrome, and estradiol deficiency may lead to osteoporosis. While effective treatment of the underlying hormone deficiencies may improve these risks, it is often necessary to treat them directly.
CA certificate Validation weaknesses Certificate_authority_compromise > Validation weaknesses Domain validation suffers from certain structural security limitations. In particular, it is always vulnerable to attacks that allow an adversary to observe the domain validation probes that CAs send. These can include attacks against the DNS, TCP, or BGP protocols (which lack the cryptographic protections of TLS/SSL), or the compromise of routers. Such attacks are possible either on the network near a CA, or near the victim domain itself.
Liskov substitution principle Principle Liskov_substitution_principle > Principle The history constraint prohibits this. It was the novel element introduced by Liskov and Wing. A violation of this constraint can be exemplified by defining a mutable point as a subtype of an immutable point.
Method inlining Effect on performance Method_inlining > Effect on performance In lower-level imperative languages such as C and Fortran it is typically a 10–20% speed boost, with minor impact on code size, while in more abstract languages it can be significantly more important, due to the number of layers inlining removes, with an extreme example being Self, where one compiler saw improvement factors of 4 to 55 by inlining.The direct benefits of eliminating a function call are: It eliminates instructions required for a function call, both in the calling function and in the callee: placing arguments on stack or in registers, the function call itself, the function prologue, then at return the function epilogue, the return statement, and then getting the return value back, and removing arguments from stacks and restoring registers (if necessary). Due to not needing registers to pass arguments, it reduces register spilling. It eliminates having to pass references and then dereference them, when using call by reference (or call by address, or call by sharing).The primary benefit of inlining, however, is the further optimizations it allows.
Tap water Summary Domestic_water_system Tap water (also known as faucet water, running water, or municipal water) is water supplied through a tap, a water dispenser valve. In many countries, tap water usually has the quality of drinking water. Tap water is commonly used for drinking, cooking, washing, and toilet flushing. Indoor tap water is distributed through indoor plumbing, which has existed since antiquity but was available to very few people until the second half of the 19th century when it began to spread in popularity in what are now developed countries.
Lava filter Method Lava_filter > Method It also functions to make nutrients available to the bacteria. Percolating water collected at the filter bottom contains odour components as well as sulfuric acid from the biological oxidation of hydrogen sulfide. Depending on the process design the collected water is recirculated or subjected to further treatment.
Abbreviated Test Language for All Systems Implementations Abbreviated_Test_Language_for_All_Systems > Implementations RCA developed a compiler for their EQUATE (Electronic Quality Assurance Test Equipment) testers. Marconi Space and Defence Systems (before they were Ferranti or GEC-Avionics) developed a compiler for their test systems called MATLAS.
Geometric Shapes History Geometric_Shapes_(Unicode_block) > History The following Unicode-related documents record the purpose and process of defining specific characters in the Geometric Shapes block:
Acid ionization constant Experimental determination Acidity_constant > Experimental determination The experimental determination of pKa values is commonly performed by means of titrations, in a medium of high ionic strength and at constant temperature. A typical procedure would be as follows. A solution of the compound in the medium is acidified with a strong acid to the point where the compound is fully protonated. The solution is then titrated with a strong base until all the protons have been removed.
Homomorphic encryption First-generation FHE Fully_homomorphic_encryption > History > First-generation FHE Craig Gentry, using lattice-based cryptography, described the first plausible construction for a fully homomorphic encryption scheme in 2009. Gentry's scheme supports both addition and multiplication operations on ciphertexts, from which it is possible to construct circuits for performing arbitrary computation. The construction starts from a somewhat homomorphic encryption scheme, which is limited to evaluating low-degree polynomials over encrypted data; it is limited because each ciphertext is noisy in some sense, and this noise grows as one adds and multiplies ciphertexts, until ultimately the noise makes the resulting ciphertext indecipherable. Gentry then shows how to slightly modify this scheme to make it bootstrappable, i.e., capable of evaluating its own decryption circuit and then at least one more operation.
Group selectionism Multilevel selection theory Group_selectionism > Multilevel selection theory Kin selection or inclusive fitness is accepted as an explanation for cooperative behavior in many species, but the scientist David Sloan Wilson argues that human behavior is difficult to explain with only this approach. In particular, he claims it does not seem to explain the rapid rise of human civilization. Wilson has argued that other factors must also be considered in evolution. Wilson and others have continued to develop group selection models.Early group selection models were flawed because they assumed that genes acted independently; but genetically based interactions among individuals are ubiquitous in group formation because genes must cooperate for the benefit of association in groups to enhance the fitness of group members.
Strength reduction Many optimizations Strength_reduction > Strength reduction example > Many optimizations Instead of using r3, the compiler can eliminate r3 and use r9. The loop, instead of being controlled by r3 = 0 to n-1, can be controlled by r9=r8+0 to r8+n-1. That adds four instructions and kills four instructions, but there's one fewer instruction inside the loop.
Aquatic feeding mechanisms Filter feeding Aquatic_predation > Filter versus suspension feeding > Filter feeding In filter feeding, the water flow is primarily generated by the organism itself, for example by creating a pressure gradient, by active swimming, or by ciliary movements.
Organic personality disorder Differential diagnosis Organic_personality_disorder > Diagnosis > Differential diagnosis Being an organic disorder, differential diagnosis between mental disorders and OPD is necessary. According to the ICD-11, specific considerations for differential diagnosis include delerium, dementia, personality disorders, impulse control disorder, and addictive behavior syndrome. For differential diagnosis in the ICD-10, along with personality disorders, there are two mentioned conditions in the ICD-10 under the same diagnostic category "F07" for consideration: postencephalitic parkinsonism (called "postencephalitic syndrome" in the ICD-10) and post-concussion syndrome.
Product testing Summary Product_testing Product testing might be accomplished by a manufacturer, an independent laboratory, a government agency, etc. Often an existing formal test method is used as a basis for testing. Other times engineers develop methods of test which are suited to the specific purpose. Comparative testing subjects several replicate samples of similar products to identical test conditions.
Criticism of the theory of relativity Bad Nauheim Debate Criticism_of_the_theory_of_relativity > General relativity > Bad Nauheim Debate Lenard also argued that Einstein's general theory of relativity admits the existence of superluminal velocities, in contradiction to the principles of special relativity; for example, in a rotating coordinate system in which the Earth is at rest, the distant points of the whole universe are rotating around Earth with superluminal velocities. However, as Weyl pointed out, it is incorrect to handle a rotating extended system as a rigid body (neither in special nor in general relativity)—so the signal velocity of an object never exceeds the speed of light. Another criticism that was raised by both Lenard and Gustav Mie concerned the existence of "fictitious" gravitational fields in accelerating frames, which according to Einstein's Equivalence Principle are no less physically real than those produced by material sources.
Molecular cell biology Cell types Cellular_Biology > Cell types There are many processes that occur in prokaryotic cells that allow them to survive. In prokaryotes, mRNA synthesis is initiated at a promoter sequence on the DNA template comprising two consensus sequences that recruit RNA polymerase. The prokaryotic polymerase consists of a core enzyme of four protein subunits and a σ protein that assists only with initiation. For instance, in a process termed conjugation, the fertility factor allows the bacteria to possess a pilus which allows it to transmit DNA to another bacteria which lacks the F factor, permitting the transmittance of resistance allowing it to survive in certain environments.
Filgrastim Medical uses Filgrastim > Medical uses Filgrastim is used to treat neutropenia; acute myeloid leukemia; nonmyeloid malignancies; leukapheresis; congenital neutropenia‚ cyclic neutropenia‚ or idiopathic neutropenia; and myelosuppressive doses of radiation.Tbo-filgrastim (Granix) is indicated for reduction in the duration of severe neutropenia in people with non-myeloid malignancies receiving myelosuppressive anti-cancer drugs associated with a clinically significant incidence of febrile neutropenia.
ALGOL 68 Expressions and compound statements ALGOL_68 > Notable language elements > Expressions and compound statements union below for example. do loop clause: DO statements OD The minimum form of a "loop clause" is thus: DO statements OD This was considered the "universal" loop, the full syntax is: FOR i FROM 1 BY -22 TO -333 WHILE i×i≠4444 DO ~ OD The construct have several unusual aspects: only the DO ~ OD portion was compulsory, in which case the loop will iterate indefinitely. thus the clause TO 100 DO ~ OD, will iterate only 100 times.
Database Design and modeling Database_language > Design and modeling This process is often called logical database design, and the output is a logical data model expressed in the form of a schema. Whereas the conceptual data model is (in theory at least) independent of the choice of database technology, the logical data model will be expressed in terms of a particular database model supported by the chosen DBMS. (The terms data model and database model are often used interchangeably, but in this article we use data model for the design of a specific database, and database model for the modeling notation used to express that design).
Trigonometry Power series representations Trigonometric_ratios > Trigonometric functions of real or complex variables > Power series representations + x 4 4 ! − x 6 6 !
Cloud-based quantum computing Existing platforms Cloud-based_quantum_computing > Existing platforms It includes a programming language, example optimization and scheduling algorithms, and quantum simulators. Q#, a quantum programming language by Microsoft on the .NET Framework seen as a successor to LIQUi|>. IBM Q Experience by IBM, providing access to quantum hardware as well as HPC simulators.
Berkeley socket interface Client Berkeley_Sockets > Client-server example using UDP > Client The following is a client program for sending a UDP packet containing the string "Hello World!" to address 127.0.0.1 at port number 7654. In this code, buffer is a pointer to the data to be sent, and buffer_length specifies the size of the data.
Seismic noise Characterization of subsurface properties Seismic_noise > Current uses of seismic noise > Characterization of subsurface properties This frequency peak allows to constrain the possible models obtain using other seismic methods but is not enough to derive a complete ground model. Moreover, it has been shown that the amplitude of the H/V peak was not related to the magnitude of the amplification.Array methods: Using an array of seismic sensors recording simultaneously the ambient vibrations allow for greater understanding of the wavefield and to derive improved images of the subsurface. In some cases, multiple arrays of different sizes may be realized and the results merged. The information of the Vertical components is only linked to the Rayleigh waves, and therefore easier to interpret, but method using the all three ground motion components are also developed, providing information about Rayleigh and Love wavefield. Seismic Interferometry methods, in particular, use correlation-based methods to estimate the seismic impulse (Green's Function) response of the Earth from background noise and have become a major area of application and research with the growth in continuously recorded high quality noise data in a wide variety of settings, ranging from the near surface to the continent scale FK, HRFK using the beamforming technique SPAC (spatial auto-correlation) method Correlations methods Refraction microtremor (ReMi)
Linear A Summary Linear_A Linear A is a writing system that was used by the Minoans of Crete from 1800 to 1450 BC to write the hypothesized Minoan language or languages. Linear A was the primary script used in palace and religious writings of the Minoan civilization. It was succeeded by Linear B, which was used by the Mycenaeans to write an early form of Greek. It was discovered by archaeologist Sir Arthur Evans.
Iron carbonyl Industrial production and use Iron_pentacarbonyl > Industrial production and use The industrial production of this compound is somewhat similar to the Mond process in that the metal is treated with carbon monoxide to give a volatile gas. In the case of iron pentacarbonyl, the reaction is more sluggish. It is necessary to use iron sponge as the starting material, and harsher reaction conditions of 5–30 MPa of carbon monoxide and 150–200 °C. Similar to the Mond process, sulfur acts as a catalyst.
Web Server New challenges (2015 and later years) Web_servers > History > New challenges (2015 and later years) In 2015, RFCs published new protocol version , and as the implementation of new specifications was not trivial at all, a dilemma arose among developers of less popular web servers (e.g. with a percentage of usage lower than 1% .. 2%), about adding or not adding support for that new protocol version.In fact supporting HTTP/2 often required radical changes to their internal implementation due to many factors (practically always required encrypted connections, capability to distinguish between HTTP/1.x and HTTP/2 connections on the same TCP port, binary representation of HTTP messages, message priority, compression of HTTP headers, use of streams also known as TCP/IP sub-connections and related flow-control, etc.) and so a few developers of those web servers opted for not supporting new HTTP/2 version (at least in the near future) also because of these main reasons: protocols HTTP/1.x would have been supported anyway by browsers for a very long time (maybe forever) so that there would be no incompatibility between clients and servers in next future; implementing HTTP/2 was considered a task of overwhelming complexity that could open the door to a whole new class of bugs that till 2015 did not exist and so it would have required notable investments in developing and testing the implementation of the new protocol; adding HTTP/2 support could always be done in future in case the efforts would be justified.Instead, developers of most popular web servers, rushed to offer the availability of new protocol, not only because they had the work force and the time to do so, but also because usually their previous implementation of SPDY protocol could be reused as a starting point and because most used web browsers implemented it very quickly for the same reason. Another reason that prompted those developers to act quickly was that webmasters felt the pressure of the ever increasing web traffic and they really wanted to install and to try – as soon as possible – something that could drastically lower the number of TCP/IP connections and speedup accesses to hosted websites.In 2020–2021 the HTTP/2 dynamics about its implementation (by top web servers and popular web browsers) were partly replicated after the publication of advanced drafts of future RFC about HTTP/3 protocol.
Lanczos approximation Introduction Lanczos_approximation > Introduction The series A is convergent, and may be truncated to obtain an approximation with the desired precision. By choosing an appropriate g (typically a small integer), only some 5–10 terms of the series are needed to compute the gamma function with typical single or double floating-point precision. If a fixed g is chosen, the coefficients can be calculated in advance and, thanks to partial fraction decomposition, the sum is recast into the following form: A g ( z ) = c 0 + ∑ k = 1 N c k z + k {\displaystyle A_{g}(z)=c_{0}+\sum _{k=1}^{N}{\frac {c_{k}}{z+k}}} Thus computing the gamma function becomes a matter of evaluating only a small number of elementary functions and multiplying by stored constants. The Lanczos approximation was popularized by Numerical Recipes, according to which computing the gamma function becomes "not much more difficult than other built-in functions that we take for granted, such as sin x or ex." The method is also implemented in the GNU Scientific Library, Boost, CPython and musl.
RunGEM Main features Gempack > Main features The original equation system is linearized (reformulated as a system of first-order partial differential equations). If most variables are expressed in terms of percentage changes (akin to log changes) the coefficients of the linearized system are usually very simple functions of database value flows. Computer algebra is used at this point to greatly reduce (by substitution) the size of the system.
Minimal standard model Higgs sector Minimal_standard_model > Theoretical aspects > Construction of the Standard Model Lagrangian > Higgs sector It is possible to perform a gauge transformation on φ {\displaystyle \varphi } such that the ground state is transformed to a basis where φ 1 = φ 2 = φ 4 = 0 {\displaystyle \varphi _{1}=\varphi _{2}=\varphi _{4}=0} and φ 3 = μ λ ≡ v {\displaystyle \varphi _{3}={\tfrac {\mu }{\sqrt {\lambda }}}\equiv v} . This breaks the symmetry of the ground state. The expectation value of φ {\displaystyle \varphi } now becomes where v {\displaystyle v} has units of mass and sets the scale of electroweak physics.
Contraction (geometry) Firmly non-expansive mapping Contraction_(geometry) > Firmly non-expansive mapping Surprisingly, while iterating non-expansive maps has no guarantee to find a fixed point (e.g. multiplication by -1), firm non-expansiveness is sufficient to guarantee global convergence to a fixed point, provided a fixed point exists. More precisely, if Fix f := { x ∈ H | f ( x ) = x } ≠ ∅ {\displaystyle {\text{Fix}}f:=\{x\in {\mathcal {H}}\ |\ f(x)=x\}\neq \varnothing } , then for any initial point x 0 ∈ H {\displaystyle x_{0}\in {\mathcal {H}}} , iterating ( ∀ n ∈ N ) x n + 1 = f ( x n ) {\displaystyle (\forall n\in \mathbb {N} )\quad x_{n+1}=f(x_{n})} yields convergence to a fixed point x n → z ∈ Fix f {\displaystyle x_{n}\to z\in {\text{Fix}}f} . This convergence might be weak in an infinite-dimensional setting.
Reciprocating internal combustion engine Gas turbines Car_engines > Combustion turbines > Gas turbines The temperature of the air, after being compressed in the compressor, is increased by burning fuel in it. The heated air and the products of combustion expand in a turbine, producing work output. About 2⁄3 of the work drives the compressor: the rest (about 1⁄3) is available as useful work output.Gas turbines are among the most efficient internal combustion engines. The General Electric 7HA and 9HA turbine combined cycle electrical plants are rated at over 61% efficiency.
Graph-encoded map Summary Graph-encoded_map In topological graph theory, a graph-encoded map or gem is a method of encoding a cellular embedding of a graph using a different graph with four vertices per edge of the original graph. It is the topological analogue of runcination, a geometric operation on polyhedra. Graph-encoded maps were formulated and named by Lins (1982).
Constant speed propeller Constant-speed propellers Propeller_governor > Mechanisms > Constant-speed propellers The CSU can be said to be to an aircraft what the continuously variable transmission is to the motorcar: the engine can be kept running at its optimum speed, regardless of the speed at which the aircraft is flying through the air. The CSU also allows aircraft engine designers to keep the ignition system simple: the automatic spark advance seen in motor vehicle engines is simplified, because aircraft engines run at a roughly constant RPM. Virtually all high-performance propeller-driven aircraft have constant-speed propellers, as they greatly improve fuel efficiency and performance, especially at high altitude.
Modal testing Shaker Modal Testing Modal_testing > Shaker Modal Testing For rotating mass shakers, the force can be calculated by knowing the mass and the speed of rotation, while for electrodynamic shakers, the force can be obtained through a load cell or an accelerometer placed on the moving mass of the shaker. Shakers have an advantage over the impact hammer as they can supply more energy to a structure over a longer period of time. However, problems can also be introduced; shakers can influence the dynamic properties of the structure and can also increase the complexity of analysis due to windowing errors.
Motor coordination Other relevant pages Motor_coordination > Other relevant pages Perceptual control theory Developmental coordination disorder Sensory processing == References ==
Protein molecule Nutrition Cellular_protein > Nutrition Most microorganisms and plants can biosynthesize all 20 standard amino acids, while animals (including humans) must obtain some of the amino acids from the diet. The amino acids that an organism cannot synthesize on its own are referred to as essential amino acids. Key enzymes that synthesize certain amino acids are not present in animals—such as aspartokinase, which catalyses the first step in the synthesis of lysine, methionine, and threonine from aspartate. If amino acids are present in the environment, microorganisms can conserve energy by taking up the amino acids from their surroundings and downregulating their biosynthetic pathways.
Transition metal carbide Summary Metal_carbido_complex A metal carbido complex is a coordination complex that contains a carbon atom as a ligand. They are analogous to metal nitrido complexes. Carbido complexes are a molecular subclass of carbides, which are prevalent in organometallic and inorganic chemistry. Carbido complexes represent models for intermediates in Fischer–Tropsch synthesis, olefin metathesis, and related catalytic industrial processes.
PowerPC applications Personal digital assistants (smartphones and tablets) PowerPC_applications > Personal digital assistants (smartphones and tablets) IBM released a Personal Digital Assistant (PDA) reference platform ("Arctic") based on PowerPC 405LP (Low Power). This project is discontinued after IBM sold PowerPC 4XX design to AMCC.
Natural Stress Conclusion Natural_Stress > Conclusion This allows more crops to be grown on a smaller amount of land. Less need for farmland allows some of it to be set aside for natural wildlife habitat. Abiotic stress only poses a problem to people or the environment if they are not prepared for it. There can be steps taken by humans to lessen the effects. Plants and animals have the ability to adapt to abiotic stress over time.
Ozone depleting Public policy Ozone-depleting_substance > Public policy After a series of scientific expeditions to the Antarctic produced convincing evidence that the ozone hole was indeed caused by chlorine and bromine from manmade organohalogens, the Montreal Protocol was strengthened at a 1990 meeting in London. The participants agreed to phase out CFCs and halons entirely (aside from a very small amount marked for certain "essential" uses, such as asthma inhalers) by 2000 in non-Article 5 countries and by 2010 in Article 5 (less developed) signatories. At a 1992 meeting in Copenhagen, the phase-out date was moved up to 1996.
Aircraft ski-jump Principle Aircraft_ski-jump > Principle A fixed-wing aircraft must build up forward speed during a lengthy takeoff roll. As the forward velocity increases, the wings produce greater amounts of lift. At a high enough speed, the lift force will exceed the weight of the aircraft, and the aircraft will become capable of sustained flight. Since the aircraft must reach flight speed using only its own engines for power, a long runway is required so that the aircraft can build up speed.
Sommerfeld constant Quotes Fine_Structure_Constant > Quotes The mystery about α is actually a double mystery: The first mystery – the origin of its numerical value α ≈ 1/137 – has been recognized and discussed for decades. The second mystery – the range of its domain – is generally unrecognized. When I die my first question to the Devil will be: What is the meaning of the fine structure constant?
Ventilator associated pneumonia Diagnosis Ventilator-associated_pneumonia > Diagnosis Alternatively, molecular detection of bacteria has been undertaken, with reports that amplifying the pan-bacterial 16S gene can provide a measure of bacterial load. A trial of biomarker-based exclusion of VAP (VAP-RAPID2) demonstrated test effectiveness but did not impact on clinical antibiotic prescribing decisions. Studies of pathogen-focussed molecular diagnostics have shown more promise in improving antimicrobial prescribing, with formal findings from the INHALE randomised controlled trial awaited. Highly sensitive molecular diagnostics have the potential to increase antimicrobial use as they detect dead or colonising bacteria, a combination of host-immune profiling and microbial detection may provide the optimal diagnostic technique.Blood cultures may reveal the microorganisms causing VAP, but are often not helpful as they are positive in only 25% of clinical VAP cases. Even in cases with positive blood cultures, the bacteremia may be from a source other than the lung infection.
Retroviral drug Entry inhibitors Management_of_HIV/AIDS > Classes of medication > Entry inhibitors Ibalizumab is effective against both CCR5 & CXCR4 tropic HIV viruses.In rare cases, individuals may have a mutation in the CCR5 delta gene which results in a nonfunctional CCR5 co-receptor and in turn, a means of resistance or slow progression of the disease. However, as mentioned previously, this can be overcome if an HIV variant that targets CXCR4 becomes dominant. To prevent fusion of the virus with the host membrane, enfuvirtide can be used. Enfuvirtide is a peptide drug that must be injected and acts by interacting with the N-terminal heptad repeat of gp41 of HIV to form an inactive hetero six-helix bundle, therefore preventing infection of host cells.
NO2F Thermodynamic properties NO2F > Thermodynamic properties The thermodynamic properties of this gas were determined by IR and Raman spectroscopy The standard heat of formation of FNO2 is -19 ± 2 kcal/mol.3 The equilibrium of the unimolecular decomposition of FNO2 lies on the side of the reactants by at least six orders of magnitude at 500 kelvin, and two orders of magnitude at 1000 kelvin. The homogeneous thermal decomposition cannot be studied at temperatures below 1200 kelvin. The equilibrium shifts towards the reactants with increasing temperature.
Transfer of learning Transfer and learning Transfer_of_learning > Transfer and learning Conditions can be environmental, physical, mental, or emotional, and the possible combinations of conditions are countless. Procedures include sequences of events or information.
Analytical Dynamics of Particles and Rigid Bodies Reprints and international editions Analytical_Dynamics_of_Particles_and_Rigid_Bodies > Publication history > Reprints and international editions McCrea, W. H. (foreword) (4th ed.). Cambridge: Cambridge University Press.
Analytic Number Theory Riemann Analytic_Number_Theory > History > Riemann Bernhard Riemann made some famous contributions to modern analytic number theory. In a single short paper (the only one he published on the subject of number theory), he investigated the Riemann zeta function and established its importance for understanding the distribution of prime numbers. He made a series of conjectures about properties of the zeta function, one of which is the well-known Riemann hypothesis.
Intralocus sexual conflict Resolution Intralocus_sexual_conflict > Resolution As a result, sexual dimorphism could pose as a resolution to intralocus sexual conflict. Another proposed hypothesis suggests that intralocus sexual conflict can be resolved through alternative splicing. In this mechanism, the sex of an organism will ultimately decide the final form of the protein that is created from a shared coding region within a set of genes.
Terminal Doppler Weather Radar Shortcomings Terminal_Doppler_Weather_Radar > Comparison with NEXRAD > Shortcomings The shorter 5 centimetres (2.0 in) wavelength, which is closer to the size of a raindrop than the 10 centimetres (3.9 in) wavelength, is partially absorbed by precipitation. This is a serious drawback to using TDWR, as the signal can be strongly attenuated in heavy precipitation. This attenuation means that the radar cannot "see" very far through heavy rain and could miss severe weather such as strong thunderstorms which may contain the signature of a tornado, when there is heavy rain falling between the radar and that storm.
Quite Universal Circuit Simulator Tool suite Quite_Universal_Circuit_Simulator > Tool suite Qucs consists of several standalone programs interacting with each other through a GUI. The GUI is used to create schematics, setup simulations, display simulation results, writing VHDL code, etc. The analog simulator, gnucsator, is a command line program which is run by the GUI in order to simulate the schematic which you previously setup. It reads a netlist file augmented with commands, performs simulations, and finally produces a dataset file. It can also report errors.
Principles of grid generation Hyperbolic schemes Principles_of_grid_generation > Techniques > Differential equation methods > Hyperbolic schemes This grid generation scheme is generally applicable to problems with open domains consistent with the type of PDE describing the physical problem. The advantage associated with hyperbolic PDEs is that the governing equations need to be solved only once for generating grid. The initial point distribution along with the approximate boundary conditions forms the required input and the solution is the then marched outward. Steger and Sorenson (1980) proposed a volume orthogonality method that uses Hyperbolic PDEs for mesh generation.
Constrained optimization Branch and bound Constrained_optimization > Solution methods > Inequality constraints > Branch and bound Constraint optimization can be solved by branch-and-bound algorithms. These are backtracking algorithms storing the cost of the best solution found during execution and using it to avoid part of the search. More precisely, whenever the algorithm encounters a partial solution that cannot be extended to form a solution of better cost than the stored best cost, the algorithm backtracks, instead of trying to extend this solution. Assuming that cost is to be minimized, the efficiency of these algorithms depends on how the cost that can be obtained from extending a partial solution is evaluated.
Prion diseases Summary Prion_diseases These include scrapie in sheep, chronic wasting disease (CWD) in deer, bovine spongiform encephalopathy (BSE) in cattle (commonly known as "mad cow disease") and Creutzfeldt–Jakob disease (CJD) in humans. All known prion diseases in mammals affect the structure of the brain or other neural tissue; all are progressive, have no known effective treatment, and are always fatal. All known mammalian prion diseases were caused by the prion protein (PrP) until 2015, when a prion form of alpha-synuclein was hypothesized to cause multiple system atrophy (MSA).Prions are a type of intrinsically disordered protein, which change their conformation unless they are bound to a specific partner such as another protein.
Hardness tester In solid mechanics Surface_hardness > In solid mechanics Deformation in the plastic range is non-linear, and is described by the stress-strain curve. This response produces the observed properties of scratch and indentation hardness, as described and measured in materials science. Some materials exhibit both elasticity and viscosity when undergoing plastic deformation; this is called viscoelasticity.
Abductive reasoning Overview Abductive_reasoning > History > Introduction and development by Peirce > Overview That is why, in the scientific method known from Galileo and Bacon, the abductive stage of hypothesis formation is conceptualized simply as induction. Thus, in the twentieth century this collapse was reinforced by Karl Popper's explication of the hypothetico-deductive model, where the hypothesis is considered to be just "a guess" (in the spirit of Peirce). However, when the formation of a hypothesis is considered the result of a process it becomes clear that this "guess" has already been tried and made more robust in thought as a necessary stage of its acquiring the status of hypothesis.
Cubic reciprocity law Facts and terminology Cubic_residue_symbol > Eisenstein integers > Facts and terminology This is a Euclidean domain with the norm function given by: N ( a + b ω ) = a 2 − a b + b 2 . {\displaystyle N(a+b\omega )=a^{2}-ab+b^{2}.} Note that the norm is always congruent to 0 or 1 (mod 3).
Half-integer spin Elementary fermions Spin_1/2_particles > Elementary fermions The Standard Model recognizes two types of elementary fermions: quarks and leptons. In all, the model distinguishes 24 different fermions. There are six quarks (up, down, strange, charm, bottom and top), and six leptons (electron, electron neutrino, muon, muon neutrino, tauon and tauon neutrino), along with the corresponding antiparticle of each of these.
Huntington's disease Huntingtin function Huntington_Disease > Mechanisms > Huntingtin function Caspase, an enzyme which plays a role in catalyzing apoptosis, is thought to be activated by the mutated gene through damaging the ubiquitin-protease system. It also acts as an antiapoptotic agent preventing programmed cell death and controls the production of brain-derived neurotrophic factor, a protein that protects neurons and regulates their creation during neurogenesis. Htt also facilitates synaptic vesicular transport and synaptic transmission, and controls neuronal gene transcription. If the expression of Htt is increased, brain cell survival is improved and the effects of mHtt are reduced, whereas when the expression of Htt is reduced, the resulting characteristics are more as seen in the presence of mHtt. Accordingly, the disease is thought not to be caused by inadequate production of Htt, but by a toxic gain-of-function of mHtt in the body.
Multipoint relay OLSR version 2 Multipoint_relay > OLSR version 2 OLSRv2 has been published by the IETF in April 2014. It maintains many of the key features of the original including MPR selection and dissemination. Key differences are the flexibility and modular design using shared components: packet format packetbb, and neighborhood discovery protocol NHDP. These components are being designed to be common among next generation IETF MANET protocols. Differences in the handling of multiple address and interface enabled nodes is also present between OLSR and OLSRv2.
Prostaglandin F synthase Reaction Prostaglandin_F_synthase > Reaction The type of amino acid that is used for protonation depends on the substrate. For example, reduction of PGD2 in the human body occurs at a pH range of 6-9, which makes histidine an ideal proton donor.The hydride that is transferred to the carbonyl oxygen of PGD2 causes weakening of the hydrogen bond between the substrate and the enzyme. This has as a result the cleavage of the product (9α,11β–PGF2) from the active site of the enzyme.
Occupational stress Workload Occupational_stress > Causes of occupational stress > Workload Underload: Having work that fails to use a worker's skills and abilities.Workload as a work demand is a major component of the demand-control model of stress. This model suggests that jobs with high demands can be stressful, especially when the individual has low control over the job. In other words, control serves as a buffer or protective factor when demands or workload is high.
Accessible toilet Technical designs Accessible_toilet > Technical designs The U.S. Department of Justice published revised regulations for Titles II and III of the Americans with Disabilities Act of 1990 "ADA" in the Federal Register on September 15, 2010. These regulations adopted revised, enforceable accessibility standards called the 2010 ADA Standards for Accessible Design "2010 Standards" or "Standards". The 2010 Standards set minimum requirements – both scoping and technical – for newly designed and constructed or altered State and local government facilities, public accommodations, and commercial facilities to be readily accessible to and usable by individuals with disabilities.
ProgramByDesign For Java ProgramByDesign > For Java Over the past few years, the team has also created a second part or phase of the curriculum. It demonstrates how the same design recipe ideas apply to a complex object-oriented programming language, such as Java. The recipes are applied initially in a functional paradigm, then introducing object-oriented concepts such as polymorphism and inheritance, and then introducing the imperative methods that are idiomatic in mainstream Java.
Carbon-fluorine bond Spectroscopy Carbon_fluorine_bond > Spectroscopy The carbon–fluorine bands are so strong that they may obscure any carbon–hydrogen bands that might be present.Organofluorine compounds can also be characterized using NMR spectroscopy, using carbon-13, fluorine-19 (the only natural fluorine isotope), or hydrogen-1 (if present). The chemical shifts in 19F NMR appear over a very wide range, depending on the degree of substitution and functional group. The table below shows the ranges for some of the major classes.
DLL trampolining History DLL_trampolining > History Later, in 1995, Thomas Lopatic independently rediscovered the buffer overflow and published his findings on the Bugtraq security mailing list. A year later, in 1996, Elias Levy (also known as Aleph One) published in Phrack magazine the paper "Smashing the Stack for Fun and Profit", a step-by-step introduction to exploiting stack-based buffer overflow vulnerabilities. Since then, at least two major internet worms have exploited buffer overflows to compromise a large number of systems.
Systems Thinking Complex adaptive systems Systems_research > System types and fields > System types > Complex adaptive systems Complex adaptive systems (CAS), coined by John H. Holland, Murray Gell-Mann, and others at the interdisciplinary Santa Fe Institute, are special cases of complex systems: they are complex in that they are diverse and composed of multiple, interconnected elements; they are adaptive in that they have the capacity to change and learn from experience. In contrast to control systems, in which negative feedback dampens and reverses disequilibria, CAS are often subject to positive feedback, which magnifies and perpetuates changes, converting local irregularities into global features.
Geodesic (general relativity) Geodesics as curves of stationary interval Geodesics_in_general_relativity > Geodesics as curves of stationary interval Any curve that differs from the geodesic purely spatially (i.e. does not change the time coordinate) in any inertial frame of reference will have a longer proper length than the geodesic, but a curve that differs from the geodesic purely temporally (i.e. does not change the space coordinates) in such a frame of reference will have a shorter proper length. The interval of a curve in spacetime is l = ∫ | g μ ν x ˙ μ x ˙ ν | d s . {\displaystyle l=\int {\sqrt {\left|g_{\mu \nu }{\dot {x}}^{\mu }{\dot {x}}^{\nu }\right|}}\,ds\ .}
Particle mechanics Medieval age Mechanics > History > Medieval age According to Shlomo Pines, al-Baghdaadi's theory of motion was "the oldest negation of Aristotle's fundamental dynamic law , anticipation in a vague fashion of the fundamental law of classical mechanics . "Influenced by earlier writers such as Ibn Sina and al-Baghdaadi, the 14th-century French priest Jean Buridan developed the theory of impetus, which later developed into the modern theories of inertia, velocity, acceleration and momentum. This work and others was developed in 14th-century England by the Oxford Calculators such as Thomas Bradwardine, who studied and formulated various laws regarding falling bodies. The concept that the main properties of a body are uniformly accelerated motion (as of falling bodies) was worked out by the 14th-century Oxford Calculators.
SnI2 Summary SnI2 Tin(II) iodide, also known as stannous iodide, is an ionic tin salt of iodine with the formula SnI2. It has a formula weight of 372.519 g/mol. It is a red to red-orange solid. Its melting point is 320 °C, and its boiling point is 714 °C.Tin(II) iodide can be synthesised by heating metallic tin with iodine in 2 M hydrochloric acid. Sn + I2 → SnI2 == References ==
Ketogenesis Regulation Ketogenesis > Regulation Ketogenesis may or may not occur, depending on levels of available carbohydrates in the cell or body. This is closely related to the paths of acetyl-CoA: When the body has ample carbohydrates available as energy source, glucose is completely oxidized to CO2; acetyl-CoA is formed as an intermediate in this process, first entering the citric acid cycle followed by complete conversion of its chemical energy to ATP in oxidative phosphorylation. When the body has excess carbohydrates available, some glucose is fully metabolized, and some of it is stored in the form of glycogen or, upon citrate excess, as fatty acids (see lipogenesis). Coenzyme A is recycled at this step.
Kidney disease Diabetes Renal_hypertrophy > Causes > Diabetes Diabetic nephropathy is a progressive kidney disease caused by angiopathy of the capillaries in the glomeruli. It is characterized by nephrotic syndrome and diffuse scarring of the glomeruli. It is particularly associated with poorly managed diabetes mellitus and is a primary reason for dialysis in many developed countries. It is classified as a small blood vessel complication of diabetes.
Tukey's lemma Applications Teichmüller–Tukey_lemma > Applications In linear algebra, the lemma may be used to show the existence of a basis. Let V be a vector space. Consider the collection F {\displaystyle {\mathcal {F}}} of linearly independent sets of vectors. This is a collection of finite character. Thus, a maximal set exists, which must then span V and be a basis for V.
Giuseppe Vitali Mathematical contributions Giuseppe_Vitali > Mathematical contributions In 1905 Vitali was the first to give an example of a non-measurable subset of real numbers, see Vitali set. His covering theorem is a fundamental result in measure theory. He also proved several theorems concerning convergence of sequences of measurable and holomorphic functions. The Vitali convergence theorem generalizes Lebesgue's dominated convergence theorem.
Nicolas Léonard Sadi Carnot Carnot cycle Nicolas_Léonard_Sadi_Carnot > Reflections on the Motive Power of Fire > Carnot cycle Carnot further postulated that no caloric is lost during the operation of his idealized engine. The process being completely reversible executed by this kind of heat engine is the most efficient possible process. The assumption that heat conduction driven by a temperature difference cannot exist, so that no caloric is lost by the engine, guided him to design the Carnot-cycle to be operated by his idealized engine.
Special Whitehead group Summary Matsumoto's_theorem_(K-theory) For example, if F is a field, then K0(F) is isomorphic to the integers Z and is closely related to the notion of vector space dimension. For a commutative ring R, the group K0(R) is related to the Picard group of R, and when R is the ring of integers in a number field, this generalizes the classical construction of the class group. The group K1(R) is closely related to the group of units R×, and if R is a field, it is exactly the group of units. For a number field F, the group K2(F) is related to class field theory, the Hilbert symbol, and the solvability of quadratic equations over completions. In contrast, finding the correct definition of the higher K-groups of rings was a difficult achievement of Daniel Quillen, and many of the basic facts about the higher K-groups of algebraic varieties were not known until the work of Robert Thomason.
Chaos game Summary Chaos_game In mathematics, the term chaos game originally referred to a method of creating a fractal, using a polygon and an initial point selected at random inside it. The fractal is created by iteratively creating a sequence of points, starting with the initial random point, in which each point in the sequence is a given fraction of the distance between the previous point and one of the vertices of the polygon; the vertex is chosen at random in each iteration. Repeating this iterative process a large number of times, selecting the vertex at random on each iteration, and throwing out the first few points in the sequence, will often (but not always) produce a fractal shape. Using a regular triangle and the factor 1/2 will result in the Sierpinski triangle, while creating the proper arrangement with four points and a factor 1/2 will create a display of a "Sierpinski Tetrahedron", the three-dimensional analogue of the Sierpinski triangle.
Existential risks from artificial general intelligence Skepticism Orthogonality_thesis > Perspectives > Skepticism I think the worry stems from a fundamental error in not distinguishing the difference between the very real recent advances in a particular aspect of AI and the enormity and complexity of building sentient volitional intelligence." Baidu Vice President Andrew Ng stated in 2015 that AI existential risk is "like worrying about overpopulation on Mars when we have not even set foot on the planet yet." For the danger of uncontrolled advanced AI to be realized, the hypothetical AI may have to overpower or out-think any human, which some experts argue is a possibility far enough in the future to not be worth researching.Skeptics who believe AGI is not a short-term possibility often argue that concern about existential risk from AI is unhelpful because it could distract people from more immediate concerns about the impact of AI, because it could lead to government regulation or make it more difficult to fund AI research, or because it could damage the field's reputation.
Proximate causation Summary Proximate_causation Ultimate cause: Because the ship hit a rock which tore open the hole in the ship's hull.In most situations, an ultimate cause may itself be a proximate cause in comparison to a further ultimate cause. Hence we can continue the above example as follows: Example: Why did the ship hit the rock? Proximate cause: Because the ship failed to change course to avoid it.