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Stochastic Neural Analog Reinforcement Calculator Summary Stochastic_Neural_Analog_Reinforcement_Calculator At this point, the operator will press a button to give reward to the machine. At this point, a large motor starts and there is a chain that goes to all 40 synapse machines, checking if the clutch is engaged or not. As the capacitor can only "remember" for a certain amount of time, the chain only catches the most recent updates of the probabilities.
Brain connectivity Applications Brain_connectivity > Applications (The dynamics of propagation may be observed in animations). Another applications of SDTF concerned evaluation of transmission during cognitive experiments. The results of the Continuous Attention Test (CAT) confirmed the engagement of prefrontal and frontal structures in the task and supported the hypothesis of an active inhibition by pre-SMA and right inferior frontal cortex.
Ostrich meat Breathing adaptations Struthio_camelus > Physiology > Thermoregulation > Breathing adaptations The trachea acts as a buffer for evaporation because of the length and the controlled vascularization. The Gular is also heavily vascularized; its purpose is for cooling blood, but also evaporation, as previously stated. Air flowing through the trachea can be either laminar or turbulent depending on the state of the bird.
Coastal geography Wave action and longshore drift Coastal_geography > Wave action and longshore drift Due to gravity, the water then falls back perpendicular to the beach, dropping its sediment as it loses energy (this is called backwash). The sediment is then picked up by the next wave and pushed slightly further down the beach, resulting in a continual movement of sediment in one direction. This is the reason why long strips of coast are covered in sediment, not just the areas around river mouths, which are the main sources of beach sediment.
Artificial satellite Power Satellite > Components > Power Most satellites use solar panels to generate power, and a few in deep space with limited sunlight use radioisotope thermoelectric generators. Slip rings attach solar panels to the satellite; the slip rings can rotate to be perpendicular with the sunlight and generate the most power. All satellites with a solar panel must also have batteries, because sunlight is blocked inside the launch vehicle and at night. The most common types of batteries for satellites are lithium-ion, and in the past nickel–hydrogen. : 88–89
Autoimmune urticaria History Autoimmune_urticaria > History The first article that discussed urticaria as a type I hypersensitivity was in 1962.In the 1980s and 1990s, researchers discovered that a significant proportion of patients with CSU had circulating autoantibodies, particularly against the high-affinity IgE receptor (FcεRI) and IgE itself. These autoantibodies were found to be capable of activating mast cells and basophils, the key effector cells in urticaria, leading to the release of histamine and other inflammatory mediators that cause the characteristic hives and itching. One of the key studies that shaped the current understanding of autoimmune urticaria was published by Hide et al. in 1993.
Intermittent claudication Treatment Intermittent_claudication > Treatment Medicines that control lipid profile, diabetes, and hypertension may increase blood flow to the affected muscles and allow for increased activity levels. Angiotensin converting enzyme inhibitors, adrenergic agents such as alpha-1 blockers and beta-blockers and alpha-2 agonists, antiplatelet agents (aspirin and clopidogrel), naftidrofuryl, pentoxifylline, and cilostazol (selective PDE3 inhibitor) are used for the treatment of intermittent claudication. However, medications will not remove the blockages from the body.
AC adapters Modes of operation AC_adapter > Modes of operation Originally, most AC/DC adapters were linear power supplies, containing a transformer to convert the mains electricity voltage to a lower voltage, a rectifier to convert it to pulsating DC, and a filter to smooth the pulsating waveform to DC, with residual ripple variations small enough to leave the powered device unaffected. Size and weight of the device was largely determined by the transformer, which in turn was determined by the power output and mains frequency. Ratings over a few watts made the devices too large and heavy to be physically supported by a wall outlet. The output voltage of these adapters varied with load; for equipment requiring a more stable voltage, linear voltage regulator circuitry was added.
RNA modification RNA editing may be involved in RNA degradation RNA_modification > RNA editing may be involved in RNA degradation A study looked at the involvement of RNA editing in RNA degradation. The researchers specifically looked at the interaction between ADAR and UPF1, an enzyme involved in the nonsense-mediated mRNA decay pathway (NMD). They found that ADAR and UPF1 are found within the suprasliceosome and they form a complex that leads to the down-regulation of specific genes. The exact mechanism or the exact pathways that these two are involved in are unknown at this time. The only fact that this research has shown is that they form a complex and down-regulate specific genes.
Paul Virilio Sokal and Bricmont Paul_Virilio > Ideas > Reception > Sokal and Bricmont We confess our sympathy with many of Virilio's political and social views; but the cause is not, alas, helped by his pseudo-physics. : 169 A criticism of a passage often reads something like this: Here Virilio mixes up velocity (vitesse) and acceleration, the two basic concepts of kinematics (the description of motion), which are introduced and carefully distinguished at the beginning of every introductory physics course. Perhaps this confusion isn't worth stressing; but for a purported specialist in the philosophy of speed, it is nonetheless a bit surprising.
Relationships and health Models Relationships_and_health > Models Indeed, men seem to need a social network that supports them for self-control, while women seem to need a social network that helps them recognize their problems. Thus, it seems important that the theoretical models include some other factors, such as gender, to explain the links between social networks and health outcomes. Despite this kind of criticism, both models have been supported by many studies.
Symmetric Multi-Processor Programming Symmetric_multiprocessing > Programming Uniprocessor and SMP systems require different programming methods to achieve maximum performance. Programs running on SMP systems may experience an increase in performance even when they have been written for uniprocessor systems. This is because hardware interrupts usually suspends program execution while the kernel that handles them can execute on an idle processor instead. The effect in most applications (e.g. games) is not so much a performance increase as the appearance that the program is running much more smoothly.
Thermodynamic equations Maxwell relations Thermodynamic_equations > Second order equations > Maxwell relations Maxwell relations are equalities involving the second derivatives of thermodynamic potentials with respect to their natural variables. They follow directly from the fact that the order of differentiation does not matter when taking the second derivative. The four most common Maxwell relations are: The thermodynamic square can be used as a tool to recall and derive these relations.
Glossary of gene expression terms A Glossary_of_genetics_(0–L) > A autosome Any chromosome that is not an allosome and hence is not involved in the determination of the sex of an organism. Unlike the sex chromosomes, the autosomes in a diploid cell exist in pairs, with the members of each pair having the same structure, morphology, and genetic loci. autozygote A cell or organism that is homozygous for a locus at which the two homologous alleles are identical by descent, both having been derived from a single gene in a common ancestor. Contrast allozygote.
Nuclear potential energy Local approximation Nuclear_potential_energy > Gravitational potential energy > Local approximation The work done equals the force required to move it upward multiplied with the vertical distance it is moved (remember W = Fd). The upward force required while moving at a constant velocity is equal to the weight, mg, of an object, so the work done in lifting it through a height h is the product mgh. Thus, when accounting only for mass, gravity, and altitude, the equation is: where U is the potential energy of the object relative to its being on the Earth's surface, m is the mass of the object, g is the acceleration due to gravity, and h is the altitude of the object.Hence, the potential difference is
Atherosclerotic plaques Lesser or uncertain Atherosclerotic_plaques > Risk factors > Lesser or uncertain Thrombophilia Saturated fat Excessive carbohydrates Elevated triglycerides Systemic inflammation Hyperinsulinemia Sleep deprivation Air pollution Sedentary lifestyle Arsenic poisoning Alcohol Chronic stress Hypothyroidism Periodontal disease
Dormancy Summary Dormancy Organisms can synchronize entry to a dormant phase with their environment through predictive or consequential means. Predictive dormancy occurs when an organism enters a dormant phase before the onset of adverse conditions. For example, photoperiod and decreasing temperature are used by many plants to predict the onset of winter.
Trace scheduling Summary Trace_scheduling Trace scheduling is an optimization technique developed by Josh Fisher used in compilers for computer programs.A compiler often can, by rearranging its generated machine instructions for faster execution, improve program performance. It increases ILP (Instruction Level Parallelism) along the important execution path by statically predicting frequent execution path. Trace scheduling is one of many known techniques for doing so.A trace is a sequence of instructions, including branches but not including loops, that is executed for some input data. Trace scheduling uses a basic block scheduling method to schedule the instructions in each entire trace, beginning with the trace with the highest frequency.
J. Robert Oppenheimer Scientific work J._Robert_Oppenheimer > Early career > Scientific work In 1931, he co-wrote a paper, "Relativistic Theory of the Photoelectric Effect", with his student Harvey Hall, in which, based on empirical evidence, he correctly disputed Dirac's assertion that two of the energy levels of the hydrogen atom have the same energy. Subsequently, one of his doctoral students, Willis Lamb, determined that this was a consequence of what became known as the Lamb shift, for which Lamb was awarded the Nobel Prize in physics in 1955.With Melba Phillips, the first graduate student to begin her PhD under Oppenheimer's supervision, Oppenheimer worked on calculations of artificial radioactivity under bombardment by deuterons. When Ernest Lawrence and Edwin McMillan bombarded nuclei with deuterons they found the results agreed closely with the predictions of George Gamow, but when higher energies and heavier nuclei were involved, the results did not conform to the theory.
Shapley–Folkman lemma Probability and measure theory Shapley–Folkman_lemma > Applications > Probability and measure theory The Shapley–Folkman–Starr results have been widely used in the probabilistic theory of random sets, for example, to prove a law of large numbers, a central limit theorem, and a large-deviations principle. These proofs of probabilistic limit theorems used the Shapley–Folkman–Starr results to avoid the assumption that all the random sets be convex. A probability measure is a finite measure, and the Shapley–Folkman lemma has applications in non-probabilistic measure theory, such as the theories of volume and of vector measures.
Communications technologies Interpersonal Social_communication > Human > Interpersonal In this view, an exchange varies in how interpersonal it is based on a number of factors. It depends on how many people are present, and whether it happens face-to-face rather than through telephone or email. A further factor concerns the relation between the communicators.
H2O2 Redox reactions Hydrogen_Peroxide > Reactions > Redox reactions The redox properties of hydrogen peroxide depend on pH as acidic conditions exacerbate the power of oxidizing agents and basic conditions exacerbate the power of reducing agents. As hydrogen peroxide exhibits ambivalent redox properties, being simultaneously an oxidizer or a reductant, its redox behavior immediately depends on pH. In acidic solutions, H2O2 is a powerful oxidizer, stronger than chlorine, chlorine dioxide, and potassium permanganate.
Twins paradox History Twins_paradox > History In 1911, Paul Langevin gave a "striking example" by describing the story of a traveler making a trip at a Lorentz factor of γ = 100 (99.995% the speed of light). The traveler remains in a projectile for one year of his time, and then reverses direction. Upon return, the traveler will find that he has aged two years, while 200 years have passed on Earth.
Transmission eigenvalue Chemistry Transmission_coefficient_(physics) > Chemistry In chemistry, in particular in transition state theory, there appears a certain "transmission coefficient" for overcoming a potential barrier. It is (often) taken to be unity for monomolecular reactions. It appears in the Eyring equation.
Casimir vacuum Papers, books and lectures Dynamical_Casimir_Effect > Further reading > Papers, books and lectures "New developments in the Casimir effect". Physics Reports. 353 (1–3): 1–205.
Tin(II) selenide Use in energy harvesting Tin_selenide > Use in energy harvesting The Cmcm phase, which is structurally related to the low temperature Pnma phase, exhibits a substantially reduced energy gap and enhanced carrier mobilities while maintaining the ultralow thermal conductivity thus yielding the record ZT. Because of SnSe’s layered structure, which does not conduct heat well, one end of the SnSe single crystal can get hot while the other remains cool. This idea can be paralleled with the idea of a posture-pedic mattress that does not transfer vibrations laterally.
Critical line theorem Arguments for and against the Riemann hypothesis Critical_line_(mathematics) > Arguments for and against the Riemann hypothesis In contrast to these positive examples, some Epstein zeta functions do not satisfy the Riemann hypothesis even though they have an infinite number of zeros on the critical line. These functions are quite similar to the Riemann zeta function, and have a Dirichlet series expansion and a functional equation, but the ones known to fail the Riemann hypothesis do not have an Euler product and are not directly related to automorphic representations. At first, the numerical verification that many zeros lie on the line seems strong evidence for it.
Observational bias Science Observational_bias > Science The scientific method requires observations of natural phenomena to formulate and test hypotheses. It consists of the following steps: Ask a question about a natural phenomenon Make observations of the phenomenon Formulate a hypothesis that tentatively answers the question Predict logical, observable consequences of the hypothesis that have not yet been investigated Test the hypothesis' predictions by an experiment, observational study, field study, or simulation Draw a conclusion from data gathered in the experiment, or revise the hypothesis or form a new one and repeat the process Write a descriptive method of observation and the results or conclusions reached Have peers with experience researching the same phenomenon evaluate the resultsObservations play a role in the second and fifth steps of the scientific method. However, the need for reproducibility requires that observations by different observers can be comparable. Human sense impressions are subjective and qualitative, making them difficult to record or compare.
Systemic sarcoidosis Pathophysiology Cardiac_sarcoidosis > Pathophysiology Granulomatous inflammation is characterized primarily by the accumulation of macrophages and activated T-lymphocytes, with increased production of key inflammatory mediators, tumor necrosis factor alpha (TNF), interferon gamma, interleukin 2 (IL-2), IL-8, IL-10, IL-12, IL-18, IL-23 and transforming growth factor beta (TGF-β), indicative of a T helper cell-mediated immune response. Sarcoidosis has paradoxical effects on inflammatory processes; it is characterized by increased macrophage and CD4 helper T-cell activation, resulting in accelerated inflammation, but immune response to antigen challenges such as tuberculin is suppressed. This paradoxic state of simultaneous hyper- and hypoactivity is suggestive of a state of anergy. The anergy may also be responsible for the increased risk of infections and cancer.
Passive income Types of income Passive_income > Types of income What one person sees as passive income may be the active income to another person. Progressive passive income is the name for income that requires somewhat more effort. Active income is earned income including all taxable income and wages the earner receives for working.
Proximate and ultimate causation In sociology Proximate_and_ultimate_causation > In sociology Sociologists use the related pair of terms "proximal causation" and "distal causation". Proximal causation: explanation of human social behaviour by considering the immediate factors, such as symbolic interaction, understanding (Verstehen), and individual milieu that influence that behaviour. Most sociologists recognize that proximal causality is the first type of power humans experience; however, while factors such as family relationships may initially be meaningful, they are not as permanent, underlying, or determining as other factors such as institutions and social networks (Naiman 2008: 5). Distal causation: explanation of human social behaviour by considering the larger context in which individuals carry out their actions.
Rock phosphate Summary Rock_phosphate Although these thick beds can exist, they are rarely only composed of phosphatic sedimentary rocks. Phosphatic sedimentary rocks are commonly accompanied by or interbedded with shales, cherts, limestone, dolomites and sometimes sandstone. These layers contain the same textures and structures as fine-grained limestones and may represent diagenetic replacements of carbonate minerals by phosphates.
Thermoplastic Polyethylene Thermoplastic_composites > Polyethylene It is flexible at room temperature (and low temperature) and can be heat sealed. Since it is an inexpensive plastic it is made in large amounts to cater to the demand.
Quantity equation Affine quantities Quantity_equation > Geometry: position vs. displacement > Affine quantities To assign a number to an affine unit, one must not only choose a unit of measurement, but also a point of reference, while to assign a number to a vector unit only requires a unit of measurement. Thus some physical quantities are better modeled by vectorial quantities while others tend to require affine representation, and the distinction is reflected in their dimensional analysis. This distinction is particularly important in the case of temperature, for which the numeric value of absolute zero is not the origin 0 in some scales.
Point and click Fitts's Law Point_and_click > Fitts's Law D {\displaystyle D} is the distance from the starting point to the center of the target. W {\displaystyle W} is the width of the target measured along the axis of motion. W {\displaystyle W} can also be thought of as the allowed error tolerance in the final position since the final point of the motion must fall within ± W 2 {\displaystyle \pm {\frac {W}{2}}} of the target's centre.
Wheeler–Feynman absorber theory Criticism Wheeler–Feynman_absorber_theory > Criticism Finally, the main drawback of the theory turned out to be the result that particles are not self-interacting. Indeed, as demonstrated by Hans Bethe, the Lamb shift necessitated a self-energy term to be explained. Feynman and Bethe had an intense discussion over that issue, and eventually Feynman himself stated that self-interaction is needed to correctly account for this effect.
Homotopy category The naive homotopy category Homotopy_category_of_topological_spaces > The naive homotopy category The category of topological spaces Top has objects the topological spaces and morphisms the continuous maps between them. The older definition of the homotopy category hTop, called the naive homotopy category for clarity in this article, has the same objects, and a morphism is a homotopy class of continuous maps. That is, two continuous maps f: X → Y are considered the same in the naive homotopy category if one can be continuously deformed to the other.
Direct-methanol fuel cell Reaction Direct_Methanol_Fuel_Cell > Reaction The half-reactions are: Methanol and water are adsorbed on a catalyst usually made of platinum and ruthenium particles, and lose protons until carbon dioxide is formed. As water is consumed at the anode in the reaction, pure methanol cannot be used without provision of water via either passive transport such as back diffusion (osmosis), or active transport such as pumping. The need for water limits the energy density of the fuel.
Asexual reproduction Alternation between sexual and asexual reproduction Reproduce_asexually > Alternation between sexual and asexual reproduction This cycle allows them to reproduce very quickly. However, most species reproduce sexually once a year. This switch is triggered by environmental changes in the fall and causes females to develop eggs instead of embryos.
Programming Language Summary Dialect_(computing) A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language. The description of a programming language is usually split into the two components of syntax (form) and semantics (meaning), which are usually defined by a formal language.
Natural pattern Deming and Shewhart Natural_pattern > Importance to statistics > Deming and Shewhart Deming held that the disjoint nature of population and sampling frame was inherently problematic once the existence of special-cause variation was admitted, rejecting the general use of probability and conventional statistics in such situations. He articulated the difficulty as the distinction between analytic and enumerative statistical studies. Shewhart argued that, as processes subject to special-cause variation were inherently unpredictable, the usual techniques of probability could not be used to separate special-cause from common-cause variation. He developed the control chart as a statistical heuristic to distinguish the two types of variation. Both Deming and Shewhart advocated the control chart as a means of assessing a process's state of statistical control and as a foundation for forecasting.
Equilibrium state Cited bibliography Thermodynamical_equilibrium > Cited bibliography Thermal Physics, second edition, W.A. Benjamin, Inc, New York. Münster, A.
Hobbing machine Cycloidal forms Hobbing > Uses > Cycloidal forms Cycloidal type gears. Double circular arc type gears). Tolerances of concentricity of the hob limit the lower modules which can be cut practically by hobbing to about 0.5 module.
Vaccine hesitancy Population health Vaccine_overload > Effectiveness > Population health Increasing herd immunity during an outbreak or when there is a risk of an outbreak is perhaps the most widely accepted justification for mass vaccination. When a new vaccine is introduced, mass vaccination can help increase coverage rapidly.If enough of a population is vaccinated, herd immunity takes effect, decreasing risk to people who cannot receive vaccines because they are too young or old, immunocompromised, or have severe allergies to the ingredients in the vaccine. The outcome for people with compromised immune systems who get infected is often worse than that of the general population.
Lubrication Fluid-lubricated systems Boundary_lubrication > Lubrication mechanisms > Fluid-lubricated systems Due to the strong coupling between lubricant hydrodynamic action and the elastic deformation in contacting solids, this regime of lubrication is an example of Fluid-structure interaction. The classical elastohydrodynamic theory considers Reynolds equation and the elastic deflection equation to solve for the pressure and deformation in this lubrication regime. Contact between raised solid features, or asperities, can also occur, leading to a mixed-lubrication or boundary lubrication regime.
Application of CFD in thermal power plants Finite volume method Application_of_CFD_in_thermal_power_plants > Methods > Finite volume method The governing equations in their differential form are integrated over each control volume. The resulting integral conservation laws are exactly satisfied for each control volume and for the entire domain, which is a distinct advantage of the finite volume method. Each integral term is then converted into a discrete form, thus yielding discretised equations at the centroids, or nodal points, of the control volumes.
Lia Bronsard Contributions Lia_Bronsard > Contributions In her research, she has used geometric flows to model the interface dynamics of reaction–diffusion systems. Other topics in her research include pattern formation, grain boundaries, and vortices in superfluids.
Photobiology Photosynthesis Photobiology > Plant Photobiology > Photosynthesis Photosynthesis is defined as a series of biochemical reactions that phototrophic cells perform to transform light energy to chemical energy and store it in carbon-carbon bonds of carbohydrates. As it is widely known, this process happens inside of the chloroplast of photosynthetic plant cells where light absorbing pigments can be found embedded in the membranes of structures called thylakoids. There are 2 main pigments present in the Photosystems of higher plants: chlorophyll (a or b) and carotenes. These pigments are organized to maximize the light reception and transfer, and they absorb specific wavelengths to broaden the amount of light that can be captured and used for photo-redox reactions.
Automorphism group functor In category theory Automorphism_group_functor > In category theory In particular, if G is a group viewed as a category with a single object * or, more generally, if G is a groupoid, then each functor F: G → C {\displaystyle F:G\to C} , C a category, is called an action or a representation of G on the object F ( ∗ ) {\displaystyle F(*)} , or the objects F ( Obj ⁡ ( G ) ) {\displaystyle F(\operatorname {Obj} (G))} . Those objects are then said to be G {\displaystyle G} -objects (as they are acted by G {\displaystyle G} ); cf. S {\displaystyle \mathbb {S} } -object. If C {\displaystyle C} is a module category like the category of finite-dimensional vector spaces, then G {\displaystyle G} -objects are also called G {\displaystyle G} -modules.
Schlesinger equations Properties Isomonodromic_deformation > Properties The isomonodromy equations enjoy a number of properties that justify their status as nonlinear special functions.
Robert Brout Research Robert_Brout > Research This work showed that the particles that carry the weak force acquire their mass through interactions with an all-pervasive field that is now known as the Higgs field, and that the interactions occur via particles that are widely known as Higgs bosons. As yet, these Higgs bosons had not been observed experimentally; however, most physicists believed that they exist. On July 4, 2012, it was announced at CERN that a new particle, "consistent with a Higgs boson", had been discovered with 5 sigma confidence in the mass region around 125-126 GeV.
Physical fitness Overview Physical_fitness > Overview Regarding specific function, fitness is attributed to persons who possess significant aerobic or anaerobic ability (i.e., endurance or strength). A well-rounded fitness program improves a person in all aspects of fitness compared to practicing only one, such as only cardio/respiratory or only weight training.
Intermediate representation Languages Intermediate_representation > Intermediate language > Languages (Lower-level than GENERIC; input for most optimizers; has a compact "bytecode" notation. )GCC supports generating these IRs, as a final target: HSA Intermediate Layer LLVM Intermediate Representation (converted from GIMPLE in the now-defunct llvm-gcc which uses LLVM optimizers and codegen)The LLVM compiler framework is based on the LLVM IR intermediate language, of which the compact, binary serialized representation is also referred to as "bitcode" and has been productized by Apple. Like GIMPLE Bytecode, LLVM Bitcode is useful in link-time optimization. Like GCC, LLVM also targets some IRs meant for direct distribution, including Google's PNaCl IR and SPIR. A further development within LLVM is the use of Multi-Level Intermediate Representation (MLIR) with the potential to generate code for different heterogeneous targets, and to combine the outputs of different compilers.The ILOC intermediate language is used in classes on compiler design as a simple target language.
Occam learning Improving sample complexity for common problems Occam_learning > Improving sample complexity for common problems Though Occam and PAC learnability are equivalent, the Occam framework can be used to produce tighter bounds on the sample complexity of classical problems including conjunctions, conjunctions with few relevant variables, and decision lists.
Vaccine overload Autism Vaccine_hesitancy > Vaccine myths > Autism The idea of a link between vaccines and autism has been extensively investigated and conclusively shown to be false. The scientific consensus is that there is no relationship, causal or otherwise, between vaccines and incidence of autism, and vaccine ingredients do not cause autism.Nevertheless, the anti-vaccination movement continues to promote myths, conspiracy theories, and misinformation linking the two. A developing tactic appears to be the "promotion of irrelevant research an active aggregation of several questionable or peripherally related research studies in an attempt to justify the science underlying a questionable claim".
Copper in heat exchangers Direct Exchange (DX) Geothermal Heating/Cooling Copper_in_heat_exchangers > Common applications for copper heat exchangers > Direct Exchange (DX) Geothermal Heating/Cooling Geothermal heat pump technology, variously known as "ground source," "earth-coupled," or "direct exchange," relies on circulating a refrigerant through buried copper tubing for heat exchange. These units, which are considerably more efficient than their air-source counterparts, rely on the constancy of ground temperatures below the frost zone for heat transfer. The most efficient ground source heat pumps use ACR, Type L or special-size copper tubing buried into the ground to transfer heat to or from the conditioned space. Flexible copper tube (typically 1/4-inch to 5/8-inch) can be buried in deep vertical holes, horizontally in a relatively shallow grid pattern, in a vertical fence-like arrangement in medium-depth trenches, or as custom configurations. Further information is available.
Overtaking criterion Cardinal definition Overtaking_criterion > Cardinal definition {\displaystyle x=(0,0,0,0,...)} y = ( − 1 , 2 , 0 , 0 , . . . )
Health disaster Causes Health_disaster > Causes Increase in contagiousness, transmissibility or a change in the agent's mode of transmission Changes in host susceptibility to the agent, such as waning herd immunity several years after a vaccination campaign. Zoonosis - an agent that jumps from a non-human host to a humanEpidemics can be related to seasonality of certain infectious agents. Seasonality may enter into any of the eight key elements of the system: (1) susceptible recruitment via reproduction, (2) transmission, (3) acquired immunity and recovery, (4) waning immunity, (5) natural mortality, (6) symptomatology and pathology (which may be acute or chronic, depending on the disease), (7) disease-induced mortality, and (8) cross-species transmission. Influenza, the common cold, and other infections of the upper respiratory tract, such as sore throat, occur predominantly in the winter. There is another variation, both as regards the number of people affected and the number who die in successive epidemics: the severity of successive epidemics rises and falls over periods of five or ten years.
Unit of information Systematic multiples Hexlet_(unit) > Units derived from bit > Systematic multiples Terms for large quantities of bits can be formed using the standard range of SI prefixes for powers of 10, e.g., kilo = 103 = 1000 (as in kilobit or kbit), mega = 106 = 1000000 (as in megabit or Mbit) and giga = 109 = 1000000000 (as in gigabit or Gbit). These prefixes are more often used for multiples of bytes, as in kilobyte (1 kB = 8000 bit), megabyte (1 MB = 8000000bit), and gigabyte (1 GB = 8000000000bit). However, for technical reasons, the capacities of computer memories and some storage units are often multiples of some large power of two, such as 228 = 268435456 bytes. To avoid such unwieldy numbers, people have often repurposed the SI prefixes to mean the nearest power of two, e.g., using the prefix kilo for 210 = 1024, mega for 220 = 1048576, and giga for 230 = 1073741824, and so on.
Glacial ice Glacial geology Glacier_flow > Glacial geology If a retreating glacier gains enough debris, it may become a rock glacier, like the Timpanogos Glacier in Utah. Abrasion occurs when the ice and its load of rock fragments slide over bedrock and function as sandpaper, smoothing and polishing the bedrock below. The pulverized rock this process produces is called rock flour and is made up of rock grains between 0.002 and 0.00625 mm in size.
Kelvin–Planck statement Non-equilibrium states Kelvin–Planck_statement > Non-equilibrium states For non-equilibrium situations in general, it may be useful to consider statistical mechanical definitions of other quantities that may be conveniently called 'entropy', but they should not be confused or conflated with thermodynamic entropy properly defined for the second law. These other quantities indeed belong to statistical mechanics, not to thermodynamics, the primary realm of the second law. The physics of macroscopically observable fluctuations is beyond the scope of this article.
Vertical take-off and landing Props, proprotors and advanced rotorcraft Vertical_takeoff_and_landing > History > Props, proprotors and advanced rotorcraft A different British VTOL project was the gyrodyne, where a rotor is powered during take-off and landing but which then freewheels during flight, with separate propulsion engines providing forward thrust. Starting with the Fairey Gyrodyne, this type of aircraft later evolved into the much larger twin-engined Fairey Rotodyne, that used tipjets to power the rotor on take-off and landing but which then used two Napier Eland turboprops driving conventional propellers mounted on substantial wings to provide propulsion, the wings serving to unload the rotor during horizontal flight. The Rotodyne was developed to combine the efficiency of a fixed-wing aircraft at cruise with the VTOL capability of a helicopter to provide short haul airliner service from city centres to airports.
Exergonic process Summary Exergonic_process These reactions occur spontaneously. A chemical reaction is also exergonic when spontaneous.
Bayes formula History Bayes'_Theorem > History Bayes' theorem is named after the Reverend Thomas Bayes (), also a statistician and philosopher. Bayes used conditional probability to provide an algorithm (his Proposition 9) that uses evidence to calculate limits on an unknown parameter. His work was published in 1763 as An Essay towards solving a Problem in the Doctrine of Chances. Bayes studied how to compute a distribution for the probability parameter of a binomial distribution (in modern terminology).
Oussama Khatib Summary Oussama_Khatib Oussama Khatib (Arabic: أسامة الخطيب) is a roboticist and a professor of computer science at Stanford University, and a Fellow of the IEEE. He is credited with seminal work in areas ranging from robot motion planning and control, human-friendly robot design, to haptic interaction and human motion synthesis. His work's emphasis has been to develop theories, algorithms, and technologies, that control robot systems by using models of their physical dynamics. These dynamic models are used to derive optimal controllers for complex robots that interact with the environment in real-time.
CFD-DEM model Software CFD-DEM_model > Software Open source and non-commercial software: The open source CFD software OpenFOAM includes particle methods, including DEM, and solvers that couple CFD-DEM. CFDEMcoupling (DCS Computing GmbH) couples CFD from OpenFOAM with open source DEM software, LIGGGHTS. MFiX(Open Source multiphase flow simulation package). The commercial software Simcenter STAR-CCM+ is an integrated multiphysics solution capable of CFD-DEM coupling involving single or multiphase flow, chemical reactions, electromagnetism and heat transfer
Extended evolutionary synthesis Defence of the extended synthesis Extended_evolutionary_synthesis > Further reading > Defence of the extended synthesis "Horizontal Gene Transfer in Evolution: Facts and Challenges". Proc Biol Sci. 277 (1683): 819–827.
Levitation (physics) Casimir force Levitation_(physics) > Casimir force Scientists have discovered a way of levitating ultra small objects by manipulating the so-called Casimir force, which normally causes objects to stick together due to forces predicted by quantum field theory. This is, however, only possible for micro-objects.
Anaemia of chronic disease Pathophysiology Anaemia_of_chronic_disease > Pathophysiology Therefore, the upregulation of white blood cells causes fewer stem cells to differentiate into red blood cells. This effect may be an important additional cause for the decreased erythropoiesis and red blood cell production seen in anemia of inflammation, even when erythropoietin levels are normal, and even aside from the effects of hepcidin.
The Paradox of Choice How we choose The_Paradox_of_Choice > Schwartz's thesis > How we choose Schwartz points out that later, one uses the consequences of their choice to modify their goals, the importance assigned to them, and the way future possibilities are evaluated.Schwartz relates the ideas of psychologist Herbert A. Simon from the 1950s to the psychological stress that most consumers face today. He notes some important distinctions between, what Simon termed, maximizers and satisficers. A maximizer is similar to a perfectionist, someone who needs to be assured that their every purchase or decision was the best that could be made.
Lie quadric Basic concepts Lie_sphere_geometry > Basic concepts These transformations do not preserve points in general: they are transforms of the Lie quadric, not of the plane/sphere plus point at infinity. The point-preserving transformations are precisely the Möbius transformations. The Lie transformations which fix the ideal point at infinity are the Laguerre transformations of Laguerre geometry.
Stark conjectures Summary Stark_conjectures In number theory, the Stark conjectures, introduced by Stark (1971, 1975, 1976, 1980) and later expanded by Tate (1984), give conjectural information about the coefficient of the leading term in the Taylor expansion of an Artin L-function associated with a Galois extension K/k of algebraic number fields. The conjectures generalize the analytic class number formula expressing the leading coefficient of the Taylor series for the Dedekind zeta function of a number field as the product of a regulator related to S-units of the field and a rational number. When K/k is an abelian extension and the order of vanishing of the L-function at s = 0 is one, Stark gave a refinement of his conjecture, predicting the existence of certain S-units, called Stark units. Rubin (1996) and Cristian Dumitru Popescu gave extensions of this refined conjecture to higher orders of vanishing.
Computer files Storage File_operation > Storage These are virtual files: they exist as objects within the operating system kernel. As seen by a running user program, files are usually represented either by a file control block or by a file handle. A file control block (FCB) is an area of memory which is manipulated to establish a filename etc. and then passed to the operating system as a parameter; it was used by older IBM operating systems and early PC operating systems including CP/M and early versions of MS-DOS. A file handle is generally either an opaque data type or an integer; it was introduced in around 1961 by the ALGOL-based Burroughs MCP running on the Burroughs B5000 but is now ubiquitous.
Four-square cipher Summary Four-square_cipher The four-square cipher is a manual symmetric encryption technique. It was invented by the French cryptographer Felix Delastelle. The technique encrypts pairs of letters (digraphs), and thus falls into a category of ciphers known as polygraphic substitution ciphers. This adds significant strength to the encryption when compared with monographic substitution ciphers which operate on single characters. The use of digraphs makes the four-square technique less susceptible to frequency analysis attacks, as the analysis must be done on 676 possible digraphs rather than just 26 for monographic substitution. The frequency analysis of digraphs is possible, but considerably more difficult - and it generally requires a much larger ciphertext in order to be useful.
Transparent plastic Summary Nylon_4 Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptability, plus a wide range of other properties, such as being lightweight, durable, flexible, and inexpensive to produce, has led to its widespread use.
Goto (command) Message passing GOTO_(DOS_command) > Alternatives > Message passing In non-procedural paradigms, goto is less relevant or completely absent. One of the main alternatives is message passing, which is of particular importance in concurrent computing, interprocess communication, and object oriented programming. In these cases, the individual components do not have arbitrary transfer of control, but the overall control may be scheduled in complex ways, such as via preemption. The influential languages Simula and Smalltalk were among the first to introduce the concepts of messages and objects. By encapsulating state data, object-oriented programming reduced software complexity to interactions (messages) between objects.
Asymmetrical warfare Terrorism Asymmetric_warfare > Tactical basis > Terrorism There are two opposing viewpoints on the relationship between asymmetric warfare and terrorism. In the modern context, asymmetric warfare is increasingly considered a component of fourth generation warfare. When practiced outside the laws of war, it is often defined as terrorism, though rarely by its practitioners or their supporters. The other view is that asymmetric warfare does not coincide with terrorism.
List of equations in quantum mechanics Non-relativistic time-dependent Schrödinger equation List_of_equations_in_quantum_mechanics > Equations > Wave–particle duality and time evolution > Non-relativistic time-dependent Schrödinger equation Again, summarized below are the various forms the Hamiltonian takes, with the corresponding Schrödinger equations and forms of solutions.
Basilar migraine Summary Basilar_migraine Although primarily considered to be a headache disorder, migraine is highly heterogenous in its clinical presentation and is better thought of as a spectrum disease rather than a distinct clinical entity. Disease burden can range from episodic discrete attacks, consisting of as little as several lifetime attacks, to chronic disease.Migraine is believed to be caused by a mixture of environmental and genetic factors that influence the excitation and inhibition of nerve cells in the brain. An older "vascular hypothesis" postulated that the headache of migraine is produced by vasodilation and aura by vasoconstriction, but this mechanism has been disproven.
Turing Machine Equivalent models Universal_computation > Equivalent models Kirner et al., 2009 have shown that among the general-purpose programming languages some are Turing complete while others are not. For example, ANSI C is not Turing-equivalent, as all instantiations of ANSI C (different instantiations are possible as the standard deliberately leaves certain behaviour undefined for legacy reasons) imply a finite-space memory. This is because the size of memory reference data types, called pointers, is accessible inside the language. However, other programming languages like Pascal do not have this feature, which allows them to be Turing complete in principle. It is just Turing complete in principle, as memory allocation in a programming language is allowed to fail, which means the programming language can be Turing complete when ignoring failed memory allocations, but the compiled programs executable on a real computer cannot.
Concurrent hash table Implementations Concurrent_hash_table > Implementations Since Java 1.5, concurrent hash maps are provided based upon concurrent map interface. libcuckoo provides concurrent hash tables for C/C++ allowing concurrent reads and writes. The library is available on GitHub. Threading Building Blocks provide concurrent unordered maps for C++ which allow concurrent insertion and traversal and are kept in a similar style to the C++11 std::unordered_map interface.
Idempotent (ring theory) Rings characterized by idempotents Central_idempotent > Rings characterized by idempotents A ring in which all elements are idempotent is called a Boolean ring. Some authors use the term "idempotent ring" for this type of ring. In such a ring, multiplication is commutative and every element is its own additive inverse. A ring is semisimple if and only if every right (or every left) ideal is generated by an idempotent.
Auditory cues Cueing in Parkinson's disease Auditory_cues > Cueing in Parkinson's disease Among the many problems associated with Parkinson's disease are disturbances with gait, or issues related to walking. One example of this is freezing of gait where a person with Parkinson's disease will stop walking abruptly and struggle with the inability to walk forward for a brief period. Research has shown that auditory cues associated with walking, such as the sound of footsteps in gravel, can improve conditions regarding disturbances in gait in people with Parkinson's disease.
Cpk2 (kinase) Disease cycle Cpk2_(kinase) > Disease cycle The infection occurs in repeated cycles of both asexual and sexual infection throughout the growing season. New rounds of infection are initiated by rain-splash or wind dispersal of spores. Infection begins when spores land on leaf tissue.
Concurrent data structure Summary Concurrent_data_structure In computer science, a concurrent data structure is a particular way of storing and organizing data for access by multiple computing threads (or processes) on a computer. Historically, such data structures were used on uniprocessor machines with operating systems that supported multiple computing threads (or processes). The term concurrency captured the multiplexing/interleaving of the threads' operations on the data by the operating system, even though the processors never issued two operations that accessed the data simultaneously. Today, as multiprocessor computer architectures that provide parallelism become the dominant computing platform (through the proliferation of multi-core processors), the term has come to stand mainly for data structures that can be accessed by multiple threads which may actually access the data simultaneously because they run on different processors that communicate with one another. The concurrent data structure (sometimes also called a shared data structure) is usually considered to reside in an abstract storage environment called shared memory, though this memory may be physically implemented as either a "tightly coupled" or a distributed collection of storage modules.
Machine learning Journals Machine_learning > Journals Journal of Machine Learning Research Machine Learning Nature Machine Intelligence Neural Computation IEEE Transactions on Pattern Analysis and Machine Intelligence
Surface stress Physical origins of surface stress Surface_stress > Physical origins of surface stress Surface atoms then sit in a lower average electron density than bulk atoms. The response of these surface atoms would be to attempt to reduce their interatomic distance in order to increase surrounding charge density. Therefore, surface atoms would create a positive surface stress (tensile).
Minimum mean square error Example 3 Minimum_mean-square_error > Examples > Example 3 {\displaystyle \sigma _{Z_{1}}^{2}.} Similarly, the second pollster declares their estimate to be y 2 {\displaystyle y_{2}} with an error z 2 {\displaystyle z_{2}} with zero mean and variance σ Z 2 2 . {\displaystyle \sigma _{Z_{2}}^{2}.}
Spearman's rank correlation coefficient Software implementations Spearman's_rank_correlation_coefficient > Software implementations R's statistics base-package implements the test cor.test(x, y, method = "spearman") in its "stats" package (also cor(x, y, method = "spearman") will work. The package spearmanCI computes confidence intervals. The package hermiter computes fast batch estimates of the Spearman correlation along with sequential estimates (i.e. estimates that are updated in an online/incremental manner as new observations are incorporated). Stata implementation: spearman varlist calculates all pairwise correlation coefficients for all variables in varlist. MATLAB implementation: = corr(x,y,'Type','Spearman') where r is the Spearman's rank correlation coefficient, p is the p-value, and x and y are vectors. Python has many different implementation of the spearman correlation statistic: it can be computed with the spearmanr function of the scipy.stats module, as well as with the DataFrame.corr(method='spearman') method from the pandas library, and the corr(x, y, method='spearman') function from the statistical package pingouin.
Direct process Reaction and mechanism Direct_process > Reaction and mechanism Thus, copper is oxidized from the zero oxidation state and then reduced to regenerate the catalyst.The chain reaction can be terminated in many ways. These termination processes give rise to the other products that are seen in the reaction. For example, combining two Si-Cl groups gives the SiCl2 group, which undergoes Cu-catalyzed reaction with MeCl to give MeSiCl3.In addition to copper, the catalyst optimally contains promoter metals that facilitate the reaction. Among the many promoter metals, zinc, tin, antimony, magnesium, calcium, bismuth, arsenic, and cadmium have been mentioned.
Francisco Ernesto Baralle Scientific publications Francisco_Ernesto_Baralle > Scientific publications Tito has over 200 scientific publications, some of his most cited are: "The Structure and evolution of the human b-globin gene family" “TDP-43 Mutations in Familial and Sporadic Amyotrophic Lateral Sclerosis” "Primary structure of human fibronectin: Differential splicing may generate at least 10 polypeptides from a single gene" “Genomic variants in exons and introns: identifying the splicing spoilers” “Characterisation and functional implications of the RNA binding properties of nuclear factor TDP-43, a novel splicing regulator of CFTR Exon 9” == References ==
Multi-agent learning Sequential social dilemmas Multi-agent_learning > Social dilemmas > Sequential social dilemmas Social dilemmas like prisoner's dilemma, chicken and stag hunt are "matrix games". Each agent takes only one action from a choice of two possible actions, and a simple 2x2 matrix is used to describe the reward that each agent will get, given the actions that each agent took. In humans and other living creatures, social dilemmas tend to be more complex. Agents take multiple actions over time, and the distinction between cooperating and defecting isn't as clear cut as in matrix games. The concept of a sequential social dilemma (SSD) was introduced in 2017 as an attempt to model that complexity. There is ongoing research into defining different kinds of SSDs and showing cooperative behavior in the agents that act in them.
QTc prolongation Antiarrhythmic agents QTc_prolongation > Risk factors > Drugs that cause QT prolongation > Antiarrhythmic agents Class III Class III antiarrhythmic drugs are potassium channel blockers that cause QT prolongation and are associated with TdP. Amiodarone Amiodarone works in many ways. It blocks sodium, potassium, and calcium channels, as well as alpha and beta adrenergic receptors.
Robust regression Heteroscedastic errors Robust_regression > Applications > Heteroscedastic errors One instance in which robust estimation should be considered is when there is a strong suspicion of heteroscedasticity. In the homoscedastic model, it is assumed that the variance of the error term is constant for all values of x. Heteroscedasticity allows the variance to be dependent on x, which is more accurate for many real scenarios. For example, the variance of expenditure is often larger for individuals with higher income than for individuals with lower incomes. Software packages usually default to a homoscedastic model, even though such a model may be less accurate than a heteroscedastic model. One simple approach (Tofallis, 2008) is to apply least squares to percentage errors, as this reduces the influence of the larger values of the dependent variable compared to ordinary least squares.
Benign tumour Multistage carcinogenesis Benign_tumour > Mechanism > Multistage carcinogenesis A prominent and well studied example of this phenomenon is the tubular adenoma, a common type of colon polyp which is an important precursor to colon cancer. The cells in tubular adenomas, like most tumors that frequently progress to cancer, show certain abnormalities of cell maturation and appearance collectively known as dysplasia. These cellular abnormalities are not seen in benign tumors that rarely or never turn cancerous, but are seen in other pre-cancerous tissue abnormalities which do not form discrete masses, such as pre-cancerous lesions of the uterine cervix.
DC–DC converter Electromechanical conversion DC/DC_converter > Electromechanical conversion A motor–generator set, mainly of historical interest, consists of an electric motor and generator coupled together. A dynamotor combines both functions into a single unit with coils for both the motor and the generator functions wound around a single rotor; both coils share the same outer field coils or magnets. Typically the motor coils are driven from a commutator on one end of the shaft, when the generator coils output to another commutator on the other end of the shaft. The entire rotor and shaft assembly is smaller in size than a pair of machines, and may not have any exposed drive shafts.
Ring (programming language) Summary Ring_(programming_language) Ring is a dynamically typed, general-purpose programming language. It can be embedded in C/C++ projects, extended using C/C++ code and/or used as a standalone language. The supported programming paradigms are imperative, procedural, object-oriented, functional, meta, declarative using nested structures, and natural programming. The language is portable (Windows, Linux, macOS, Android, WebAssembly, etc.) and can be used to create console, GUI, web, game and mobile applications.
LL parsing Parsing procedure LL_parsing > Concrete example > Parsing procedure The stack becomes: The parser now has an 'a' on the input stream and an 'a' at its stack top. Because they are the same, it removes it from the input stream and pops it from the top of the stack. The parser then has an '+' on the input stream and '+' is at the top of the stack meaning, like with 'a', it is popped from the stack and removed from the input stream.
Lévy's martingale convergence theorem Statement for discrete-time martingales Lévy's_martingale_convergence_theorem > Statement for discrete-time martingales As intuition, there are two reasons why a sequence may fail to converge. It may go off to infinity, or it may oscillate.
Migraine headaches Epidemiology Migraine > Epidemiology Children as young as two years may be affected. During adolescence, migraine becomes more common among women and this persists for the rest of the lifespan, being twice as common among elderly females than males. In women, migraine without aura are more common than migraine with aura; however in men the two types occur with similar frequency.During perimenopause symptoms often get worse before decreasing in severity. While symptoms resolve in about two-thirds of the elderly, in 3–10% they persist.

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