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Oxhydroelectric effect Theoretical model Oxhydroelectric_effect > Theoretical model The two phases, are characterized by different thermodynamic parameters, and are in a stable non-equilibrium state. The coherent phase should be described by a quantum state, and in particular a state oscillating between a fundamental state, where electrons are firmly bound (ionization energy of 12.60 eV), and an excited state characterized by a quasi-free electron configuration. The energy of the excited state is 12.06 eV, which means that only a small amount of energy as small as (12.60 - 12.06) eV = 0.54 eV (Infrared range) is sufficient to extract an electron.
Noble gas matrix Experimental setup Noble_gas_matrix > Experimental setup Mono-atomic gases have relatively simple face-centered cubic (fcc) crystal structure, which can make interpretations of the site occupancy and crystal-field splitting of the guest easier. In some cases a reactive material, for example, methane, hydrogen or ammonia, may be used as the host material so that the reaction of the host with the guest species may be studied. Using the matrix isolation technique, short-lived, highly-reactive species such as radical ions and reaction intermediates may be observed and identified by spectroscopic means.
Language development Theoretical frameworks Language_development > Theoretical frameworks Chomsky says that all children have what is called an innate language acquisition device (LAD). Theoretically, the LAD is an area of the brain that has a set of universal syntactic rules for all languages. This device provides children with the ability to make sense of knowledge and construct novel sentences with minimal external input and little experience.
James Collins (bioengineer) Nonlinear dynamics in biological systems James_Collins_(bioengineer) > Work > Nonlinear dynamics in biological systems Collins also pioneered the development and use of nonlinear dynamical approaches to study, mimic and improve biological function, expanding our ability to understand and harness the physics of living systems. Collins, for example, proposed that input noise could be used to enhance sensory function and motor control in humans. He and collaborators showed that touch sensation and balance control in young and older adults, patients with stroke, and patients with diabetic neuropathy could be improved with the application of sub-sensory mechanical noise, e.g., via vibrating insoles. This work has led to the creation of a new class of medical devices to address complications resulting from diabetic neuropathy, restore brain function following stroke, and improve elderly balance.
Juvenile delinquency Peer influence Juvenile_delinquency > Situational factors > Peer influence The purpose of the experiment was to see if the group would influence the participant to answer incorrectly. Asch found that seventy-six percent of the participants conformed and answered incorrectly when influenced by the group. According to these findings, it was concluded that a peer group that is involved in deviant behavior can influence an adolescent to engage in similar activities. Once the adolescent becomes part of the group, they will be susceptible to groupthink.
Federated learning Federated Learning with Dynamic Regularization (FedDyn) Federated_learning > Federated learning variations > Federated Learning with Dynamic Regularization (FedDyn) Hence, the computation complexity is linear in local dataset size. Moreover, gradient computation can be parallelizable within each device which is different from successive SGD steps. Theoretically, FedDynOneGD achieves the same convergence guarantees as in FedDyn with less local computation.
Hydrodynamic instability Summary Dynamic_instability_(fluid_mechanics) In fluid dynamics, hydrodynamic stability is the field which analyses the stability and the onset of instability of fluid flows. The study of hydrodynamic stability aims to find out if a given flow is stable or unstable, and if so, how these instabilities will cause the development of turbulence. The foundations of hydrodynamic stability, both theoretical and experimental, were laid most notably by Helmholtz, Kelvin, Rayleigh and Reynolds during the nineteenth century. These foundations have given many useful tools to study hydrodynamic stability.
Complex geometry Classification in complex geometry Complex_algebraic_geometry > Classification in complex geometry One major theme in complex geometry is classification. Due to the rigid nature of complex manifolds and varieties, the problem of classifying these spaces is often tractable. Classification in complex and algebraic geometry often occurs through the study of moduli spaces, which themselves are complex manifolds or varieties whose points classify other geometric objects arising in complex geometry.
Numerical solution of the convection–diffusion equation Finite element solution to convection–diffusion problem Numerical_solution_of_the_convection–diffusion_equation > Finite element solution to convection–diffusion problem Unlike the conduction equation (a finite element solution is used), a numerical solution for the convection–diffusion equation has to deal with the convection part of the governing equation in addition to diffusion. When the Péclet number (Pe) exceeds a critical value, the spurious oscillations result in space and this problem is not unique to finite elements as all other discretization techniques have the same difficulties. In a finite difference formulation, the spatial oscillations are reduced by a family of discretization schemes like upwind scheme.
Donald Symons Selected publications Donald_Symons > Selected publications Symons, D. (1990) "Adaptiveness and adaptation," in Ethology and Sociobiology, 11: 427–444. Symons, D.
Jeffrey Lagarias Career Jeffrey_Lagarias > Career He has since worked in many areas, both pure and applied, and considers himself a mathematical generalist.Lagarias discovered an elementary problem that is equivalent to the Riemann hypothesis, namely whether for all n > 0, we have σ ( n ) ≤ H n + e H n ln ⁡ H n {\displaystyle \sigma (n)\leq H_{n}+e^{H_{n}}\ln H_{n}} with equality only when n = 1. Here Hn is the nth harmonic number, the sum of the reciprocals of the first n {\displaystyle n} positive integers, and σ(n) is the divisor function, the sum of the positive divisors of n.He disproved Keller's conjecture in dimensions at least 10. Lagarias has also done work on the Collatz conjecture and Li's criterion and has written several highly cited papers in symbolic computation with Dave Bayer.
Outer mitochondrial membrane History Oocyte_mitochondry > History Warburg and Heinrich Otto Wieland, who had also postulated a similar particle mechanism, disagreed on the chemical nature of the respiration. It was not until 1925, when David Keilin discovered cytochromes, that the respiratory chain was described.In 1939, experiments using minced muscle cells demonstrated that cellular respiration using one oxygen molecule can form four adenosine triphosphate (ATP) molecules, and in 1941, the concept of the phosphate bonds of ATP being a form of energy in cellular metabolism was developed by Fritz Albert Lipmann. In the following years, the mechanism behind cellular respiration was further elaborated, although its link to the mitochondria was not known.
History of the periodic table Changes to the periodic table History_of_the_periodic_table > Inert gases and ether > Changes to the periodic table Although the sequence of atomic weights suggested that inert gases should be located between halogens and alkali metals, and there were suggestions to put them into group VIII coming from as early as 1895, such placement contradicted one of Mendeleev's basic considerations, that of the highest oxides. Inert gases did not form any oxides, and no other compounds at all, and as such, their placement in a group where elements should form tetroxides was seen as merely auxiliary and not natural; Mendeleev doubted inclusion of those elements in group VIII. Later developments, particularly by British scientists, focused on correspondence of inert gases with halogens to their left and alkali metals to their right. In 1898, when only helium, argon, and krypton were definitively known, Crookes suggested these elements be placed in a single column between the hydrogen group and the fluorine group.
Salt wedge (hydrology) Implications for marine life Tidal_estuary > Implications for marine life Estuaries are incredibly dynamic systems, where temperature, salinity, turbidity, depth and flow all change daily in response to the tides. This dynamism makes estuaries highly productive habitats, but also make it difficult for many species to survive year-round. As a result, estuaries large and small experience strong seasonal variation in their fish communities. In winter, the fish community is dominated by hardy marine residents, and in summer a variety of marine and anadromous fishes move into and out of estuaries, capitalizing on their high productivity.
Spore formation Reproduction via spores Spore_formation > Reproduction via spores Reproductive spores are generally the result of cell division, most commonly meiosis (e.g. in plant sporophytes). Sporic meiosis is needed to complete the sexual life cycle of the organisms using it. In some cases, sporogenesis occurs via mitosis (e.g. in some fungi and algae). Mitotic sporogenesis is a form of asexual reproduction.
Erlang (programming language) Quicksort Erlang_(programming_language) > Functional programming examples > Quicksort Quicksort in Erlang, using list comprehension: The above example recursively invokes the function qsort until nothing remains to be sorted. The expression is a list comprehension, meaning "Construct a list of elements Front such that Front is a member of Rest, and Front is less than Pivot." ++ is the list concatenation operator. A comparison function can be used for more complicated structures for the sake of readability.
Global anomaly Summary Global_anomaly This new anomaly is a mixed gauge-gravitational anomaly and a nonperturbative global anomaly.Many types of global anomalies must cancel for a theory to be consistent. An example is modular invariance, the requirement of anomaly cancellation for a part of a gravitational anomaly that deals with the large diffeomorphisms over two dimensional worldsheets of genus 1 or more. == References ==
Stem cell controversy Alternatives to embryonic stem cells Stem_cell_controversy > Alternatives to embryonic stem cells Some stem cell researchers are working to develop techniques of isolating stem cells with similar potency as embryonic stem cells, but do not require the destruction of a human embryo.
Kinetic isotope effect Tunneling Deuterium_isotope_effect > Theory > Tunneling In some cases, an additional rate enhancement is seen for the lighter isotope, possibly due to quantum mechanical tunnelling. This is typically only observed for reactions involving bonds to hydrogen atoms. Tunneling occurs when a molecule penetrates through a potential energy barrier rather than over it.
Conservation and restoration of immovable cultural property Agents of Deterioration Conservation_and_restoration_of_immovable_cultural_property > Agents of Deterioration Physical forces also include shocks and vibrations that can damage the fragile structure of the building, such as vibrations stemming from construction or large events. Building restoration and damage prevention can include training staff on proper object handling within the space, performing evaluations on structural integrity and measuring the levels of vibration that are deemed safe in and around the building. Understanding the structural health of the building, including vibration measuring, can help in determining restoration work that is safe to perform.
Thermal impedance Other quantities Thermal_conductivities > Definition > Other quantities Thermal resistance is the inverse of thermal conductance. It is a convenient measure to use in multicomponent design since thermal resistances are additive when occurring in series.There is also a measure known as the heat transfer coefficient: the quantity of heat that passes per unit time through a unit area of a plate of particular thickness when its opposite faces differ in temperature by one kelvin. In ASTM C168-15, this area-independent quantity is referred to as the "thermal conductance".
Finite intersection property General sources Strong_finite_intersection_property > References > General sources Mineola, New York: Dover Publications, Inc. ISBN 978-0-486-49353-4. OCLC 849801114. Wilansky, Albert (17 October 2008) .
Natural Step Overview of the science - Systems functions Natural_Step > Framework > FSSD System Level > Overview of the science - Systems functions Behind the framework there is a science-based understanding of the dynamic interrelationships within and between socio-ecological sub-systems and is based (a.o.) on study of ecosystems, laws of nature (including thermodynamics, conservation laws, laws of gravity, biogeochemical cycles, photosynthesis, systems thinking, flows of resources and wastes), social systems, social institutions (including trust and fundamental human needs), psychology. In order to be able to create a structured overview and not to be confused with more downstream or detailed information only the logic of the concepts are explained here.
Incident (graph theory) Path graph Graph_(discrete_mathematics) > Types of graph > Path graph A path graph or linear graph of order n ≥ 2 is a graph in which the vertices can be listed in an order v1, v2, …, vn such that the edges are the {vi, vi+1} where i = 1, 2, …, n − 1. Path graphs can be characterized as connected graphs in which the degree of all but two vertices is 2 and the degree of the two remaining vertices is 1. If a path graph occurs as a subgraph of another graph, it is a path in that graph.
Norman L. Biggs Computational Learning Theory Norman_L._Biggs > Work > Computational Learning Theory In 1997, N. Biggs and M. Anthony wrote a book titled Computational Learning Theory: an Introduction. Both Biggs and Anthony focused on the necessary background material from logic, probability, and complex theory. This book is an introduction to computational learning.
Milnesium alpigenum Reproductive cycle Milnesium_alpigenum > Reproduction > Reproductive cycle After this, the individual has reached reproductive maturity. All tardigrades including M. alpigenum implement the "R" reproductive strategy of having many offspring with little to no investment in growth. The reproductive cycle and nature of M. alpigenum is almost identical to the likes of Milnesium tardigradum.
Gauge theory (mathematics) Hitchin's equations and Higgs bundles Gauge_theory_(mathematics) > Gauge theory in one and two dimensions > Hitchin's equations and Higgs bundles This is shown through an infinite-dimensional moment map construction, and this moduli space of Higgs bundles also has a complex structure, which is different to that coming from the Hitchin pairs, leading to two complex structures on the moduli space M {\displaystyle {\mathcal {M}}} of Higgs bundles. These combine to give a third making this moduli space a hyperkähler manifold. Hitchin's work was subsequently vastly generalised by Carlos Simpson, and the correspondence between solutions to Hitchin's equations and Higgs bundles over an arbitrary Kähler manifold is known as the nonabelian Hodge theorem.
Outline (list) Applications Outline_(list) > Applications Outlines are used for composition, summarization, and as a development and storage medium.
Serotonin Biosynthesis Serotonin > Biochemical mechanisms > Biosynthesis However, tryptophan and its metabolite 5-hydroxytryptophan (5-HTP), from which serotonin is synthesized, do cross the blood–brain barrier. These agents are available as dietary supplements and in various foods, and may be effective serotonergic agents. One product of serotonin breakdown is 5-hydroxyindoleacetic acid (5-HIAA), which is excreted in the urine. Serotonin and 5-HIAA are sometimes produced in excess amounts by certain tumors or cancers, and levels of these substances may be measured in the urine to test for these tumors.
Polarising filter Use Polarizing_filter_(Photography) > Use The polarizing lens effectively absorbs these light waves, rendering outdoor scenes crisper with deeper color tones in subject matter such as blue skies, bodies of water and foliage.Much light is differentiated by polarization, e.g. light passing through crystals like sunstones (calcite) or water droplets producing rainbows. The polarization of the rainbow is caused by the internal reflection. The rays strike the back surface of the drop close to the Brewster angle.Polarizing filters can be rotated to maximize or minimize admission of polarized light.
Rotary atomizers Working Principle Rotary_atomizers > Working Principle The energy required for atomization is transferred directly from the atomizer body to the liquid. This gives us an advantage that the energy required for atomizing the liquid is directly supplied mechanically and energetically. The complicated and costly production of compressed gas, for example, compressed air, is no longer necessary. It is sufficient to feed the liquid to be atomized to the atomizer under low pressure. Sometimes a low hydrostatic pressure is adequate.
Gauge connection Quantum field theories Non-abelian_gauge_theories > Description > Quantum field theories Other than these classical continuum field theories, the most widely known gauge theories are quantum field theories, including quantum electrodynamics and the Standard Model of elementary particle physics. The starting point of a quantum field theory is much like that of its continuum analog: a gauge-covariant action integral that characterizes "allowable" physical situations according to the principle of least action. However, continuum and quantum theories differ significantly in how they handle the excess degrees of freedom represented by gauge transformations. Continuum theories, and most pedagogical treatments of the simplest quantum field theories, use a gauge fixing prescription to reduce the orbit of mathematical configurations that represent a given physical situation to a smaller orbit related by a smaller gauge group (the global symmetry group, or perhaps even the trivial group).
Immersed boundary method Summary Immersed_boundary_method Variants of this basic approach have been applied to simulate a wide variety of mechanical systems involving elastic structures which interact with fluid flows. Since the original development of this method by Peskin, a variety of approaches have been developed to simulate flow over complicated immersed bodies on grids that do not conform to the surface of the body. These include methods such as the immersed interface method, the Cartesian grid method, the ghost fluid method and the cut-cell method.
Traversal Using Relay NAT Protocol Traversal_Using_Relays_around_NAT > Protocol In other words, when a peer is finally contacted and sends information back to the TURN server to be relayed to client, the TURN server uses the permissions to verify that the peer-to-TURN server communication is valid. After permissions have been created, the client has two choices for sending the actual data, (1) it can use the Send mechanism, or (2) it can reserve a channel using the ChannelBind request. The Send mechanism is more straightforward, but contains a larger header, 36 bytes, that can substantially increase the bandwidth in a TURN relayed conversation.
Balkan endemic nephropathy Signs and symptoms Balkan_endemic_nephropathy > Signs and symptoms The patients are distinguished from those suffering from other causes of end-stage renal disease by showing an absence of high blood pressure, xanthochromia of palms and soles (Tanchev's sign), early hypochromic anemia, absence of proteinuria, and slow progression of kidney failure. There is no specific therapy; BEN causes end-stage renal disease, for which the only effective treatments are dialysis or a kidney transplant. In endemic areas BEN is responsible for up to 70% of end-stage renal disease. At least 25,000 individuals are known to have this form of the disease.Patients with BEN have a greatly increased rate of transitional cell carcinoma of the upper urothelial tract, (the renal pelvis and ureters). (In populations without BEN, most urothelial cancer occurs in the bladder. )
Machine learning in video games Long short-term memory Machine_learning_in_video_games > Overview of relevant machine learning techniques > Recurrent neural network > Long short-term memory A long short-term memory (LSTM) network is a specific implementation of a RNN that is designed to deal with the vanishing gradient problem seen in simple RNNs, which would lead to them gradually "forgetting" about previous parts of an inputted sequence when calculating the output of a current part. LSTMs solve this problem with the addition of an elaborate system that uses an additional input/output to keep track of long term data. LSTMs have achieved very strong results across various fields, and were used by several monumental deep learning agents in games.
Synthetic Biology Orthogonal approach Artificial_life_form > Four engineering approaches > Orthogonal approach It is also known as perpendicular engineering. This strategy, also referred to as "chemical synthetic biology," principally seeks to alter or enlarge the genetic codes of living systems utilising artificial DNA bases and/or amino acids. This subfield is also connected to xenobiology, a newly developed field that combines systems chemistry, synthetic biology, exobiology, and research into the origins of life. In recent decades, researchers have created compounds that are structurally similar to the DNA canonical bases to see if those "alien" or xeno (XNA) molecules may be employed as genetic information carriers.
Root mean square fluctuation Summary Mean_square_displacement In statistical mechanics, the mean squared displacement (MSD, also mean square displacement, average squared displacement, or mean square fluctuation) is a measure of the deviation of the position of a particle with respect to a reference position over time. It is the most common measure of the spatial extent of random motion, and can be thought of as measuring the portion of the system "explored" by the random walker. In the realm of biophysics and environmental engineering, the Mean Squared Displacement is measured over time to determine if a particle is spreading slowly due to diffusion, or if an advective force is also contributing.
Cold district heating (Seasonal) heat storage Cold_district_heating > Components > (Seasonal) heat storage These make it possible to store excess heat from the summer half of the year, e.g. from cooling, but also from other heat sources and thus heat up the ground. During the heating period, the process is then reversed and heated water is pumped and fed into the cold heat network. Other types of heat storage are also possible, however. For example, a cold heating network in Fischerbach uses an ice storage.
Electrical system design Summary Electrical_system_design Often the systems are combined with other systems. They might be subsystems of larger systems and have subsystems of their own. For example, a subway rapid transit electrical system is composed of the wayside electrical power supply, wayside control system, and the electrical systems of each transit car. Each transit car’s electrical system is a subsystem of the subway system. Inside of each transit car there are also subsystems, such as the car climate control system.
Luteinizing hormone-releasing hormone Function Gonadotropin_releasing_hormone > Function Pulsatile activity can be disrupted by hypothalamic-pituitary disease, either dysfunction (i.e., hypothalamic suppression) or organic lesions (trauma, tumor). Elevated prolactin levels decrease GnRH activity. In contrast, hyperinsulinemia increases pulse activity leading to disorderly LH and FSH activity, as seen in polycystic ovary syndrome (PCOS). GnRH formation is congenitally absent in Kallmann syndrome.
Sodium azide Summary Sodium_azide Sodium azide is an inorganic compound with the formula NaN3. This colorless salt is the gas-forming component in some car airbag systems. It is used for the preparation of other azide compounds. It is an ionic substance, is highly soluble in water, and is very acutely poisonous.
Viability selection Speciation Evolution_by_natural_selection > Evolution by means of natural selection > Speciation E. B. Poulton realized in 1903 that reproductive isolation could evolve through divergence, if each lineage acquired a different, incompatible allele of the same gene. Selection against the heterozygote would then directly create reproductive isolation, leading to the Bateson–Dobzhansky–Muller model, further elaborated by H. Allen Orr and Sergey Gavrilets. With reinforcement, however, natural selection can favor an increase in pre-zygotic isolation, influencing the process of speciation directly.
Adaptive memory Basic memory processes Adaptive_memory > Alternative viewpoints/explanations > Basic memory processes Basic memory processes have also been examined in terms of their relation to survival processing, in hopes of explaining the survival recall advantage. Weinstein, Bugg and Roediger contrasted two basic memory processes: schematic processing (the memory performance is made easier and more efficient with the creation of schemas) and self-referential processing (elaboration becomes easier when relating the concept to oneself). Weinstein and colleagues conducted two experiments, the first duplicating Nairne's findings, and the second comparing the survival advantage to schematic and self-referential processing. Weinstein's findings supported Nairne's survival advantage and found it unlikely that the survival advantage can be explained in terms of schematic processing or self-reference.
Strain gage In practice Strain_Gauge > In practice If these steps are not followed the strain gauge binding to the surface may be unreliable and unpredictable measurement errors may be generated. Strain gauge based technology is used commonly in the manufacture of pressure sensors. The gauges used in pressure sensors themselves are commonly made from silicon, polysilicon, metal film, thick film, and bonded foil.
Sim racing Arcade simulator era (1982–1989) Sim_racing > History of sim racing > Arcade simulator era (1982–1989) It attempted to realistically simulate car driving, with the car jumping up and down, turning back and forth, and spinning up to 180 degrees, with an emphasis on acceleration, braking, and gear shifting, along with the need for counter-steering to avoid spin-outs. It also featured a day-night cycle, accurately simulated courses approved by the Automobile Club de l'Ouest, and force feedback to simulate road vibration in the form of a vibrating steering wheel that reacts to the driver's acceleration and off-road bumps.
Psychological sciences Controlled experiments Psychological_sciences > Research methods > Controlled experiments For example, in research on the best way to affect reading achievement in the first three grades of school, school administrators may not permit educational psychologists to randomly assign children to phonics and whole language classrooms, in which case the psychologists must work with preexisting classroom assignments. Psychologists will compare the achievement of children attending phonics and whole language classes and, perhaps, statistically adjust for any initial differences in reading level. Experimental researchers typically use a statistical hypothesis testing model which involves making predictions before conducting the experiment, then assessing how well the data collected are consistent with the predictions. These predictions are likely to originate from one or more abstract scientific hypotheses about how the phenomenon under study actually works.
Omnibus test Model assumptions in multiple linear regression Omnibus_test > In multiple regression > Model assumptions in multiple linear regression Random sampling. Normal or approximately normal distribution of the errors eij. The errors eij explanatory equals zero>, E(eij)=0. Equal variances of the errors eij. Which it's omnibus F test ( like Levene F test). No Multi-collinearity between explanatory/predictor variables' meaning: cov(xi,xj)=0 where is i≠j, for any i or j.
Advanced driver-assistance system Driving task assistance Advanced_driver-assistance_system > Feature examples > Driving task assistance Adaptive cruise control (ACC) can maintain a chosen velocity and distance between a vehicle and the vehicle ahead. ACC can automatically brake or accelerate with concern to the distance between the vehicle and the vehicle ahead. ACC systems with stop and go features can come to a complete stop and accelerate back to the specified speed. This system still requires an alert driver to take in their surroundings, as it only controls speed and the distance between you and the car in front of you.
Genetically modified organisms Summary Genetically_modified_organisms Fungi have been engineered with much the same goals. Viruses play an important role as vectors for inserting genetic information into other organisms. This use is especially relevant to human gene therapy.
Pulse-Doppler signal processing Summary Pulse-Doppler_signal_processing This signal processing strategy is used in pulse-Doppler radar and multi-mode radar, which can then be pointed into regions containing a large number of slow-moving reflectors without overwhelming computer software and operators. Other signal processing strategies, like moving target indication, are more appropriate for benign clear blue sky environments. It is also used to measure blood flow in Doppler ultrasonography.
Glass-filled polymer Materials Glass-filled_polymer > Materials Either thermoplastic or thermosetting polymers may be used. One of the most widely used thermoplastics is a polyamide polymer nylon.The first mouldable composite was Bakelite. This used wood flour fibres in phenolic resin as the thermoset polymer matrix. As the fibres were only short this material had relatively low bulk strength, but still improved surface hardness and good mouldability. A wide range of polymers are now produced in glass-filled varieties, including polyamide (Nylon), acetal homopolymers and copolymers, polyester, polyphenylene oxide (PPO / Noryl), polycarbonate, polyethersulphoneBulk moulding compound is a pre-mixed material of resin and fibres supplied for moulding. Some are thermoplastic or thermosetting, others are chemically cured and are mixed with a catalyst (polyester) or hardener (epoxy) before moulding.
Rutherford Aris bibliography Journal articles Rutherford_Aris_bibliography > Journal articles "N-segment least-squares approximation" (with M.M. Denn).
Diode–transistor logic Interfacing considerations Diode–transistor_logic > Interfacing considerations A major advantage over the earlier resistor–transistor logic is increased fan-in. Additionally, to increase fan-out, an additional transistor and diode may be used.
Carboxylate ion Resonance stabilization of the carboxylate ion Carboxylate_group > Resonance stabilization of the carboxylate ion In contrast, an alkoxide ion, once formed, would have a strong negative charge localized on its lone oxygen atom, which would strongly attract any nearby protons (indeed, alkoxides are very strong bases). Because of resonance stabilization, carboxylic acids have much lower pKa values (and are therefore stronger acids) than alcohols. For example, the pKa value of acetic acid is 4.8, while ethanol has a pKa of 16.
Spliceosome Composition Spliceosome > Composition Many proteins exhibit a zinc-binding motif, which underscores the importance of zinc in the splicing mechanism. The first molecular-resolution reconstruction of U4/U6.U5 triple small nuclear ribonucleoprotein (tri-snRNP) complex was reported in 2016. Cryo-EM has been applied extensively by Shi et al. to elucidate the near-/atomic structure of spliceosome in both yeast and humans.
Orders of magnitude (numbers) 10100 (one googol) to 101000 Order_of_magnitude_(numbers) > 10100 (one googol) to 101000 (10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000; short scale: ten duotrigintillion; long scale: ten thousand sexdecillion, or ten sexdecillard) Mathematics: There are 157 152 858 401 024 063 281 013 959 519 483 771 508 510 790 313 968 742 344 694 684 829 502 629 887 168 573 442 107 637 760 000 000 000 000 000 000 000 000 (≈1.57×10116) distinguishable permutations of the V-Cube 6 (6×6×6 Rubik's Cube). Chess: Shannon number, 10120, a lower bound of the game-tree complexity of chess. Physics: 10120, discrepancy between the observed value of the cosmological constant and a naive estimate based on Quantum Field Theory and the Planck energy. Physics: 8×10120, ratio of the mass-energy in the observable universe to the energy of a photon with a wavelength the size of the observable universe.
Dictionary (data structure) Example Associative_arrays > Operations > Example Suppose that the set of loans made by a library is represented in a data structure. Each book in a library may be checked out only by a single library patron at a time. However, a single patron may be able to check out multiple books.
NP-complete problem Summary NP-complete_problem The NP-complete problems represent the hardest problems in NP. If some NP-complete problem has a polynomial time algorithm, all problems in NP do. The set of NP-complete problems is often denoted by NP-C or NPC.
Monte Carlo method in statistical physics Summary Monte_Carlo_method_in_statistical_mechanics Monte Carlo in statistical physics refers to the application of the Monte Carlo method to problems in statistical physics, or statistical mechanics.
Voltage-gated proton channels Summary Voltage-gated_proton_channel Voltage-gated proton channels are ion channels that have the unique property of opening with depolarization, but in a strongly pH-sensitive manner. The result is that these channels open only when the electrochemical gradient is outward, such that their opening will only allow protons to leave cells. Their function thus appears to be acid extrusion from cells.Another important function occurs in phagocytes (e.g. eosinophils, neutrophils, and macrophages) during the respiratory burst. When bacteria or other microbes are engulfed by phagocytes, the enzyme NADPH oxidase assembles in the membrane and begins to produce reactive oxygen species (ROS) that help kill bacteria.
Units of measure Summary Units_of_measure Scientific systems of units are a refinement of the concept of weights and measures historically developed for commercial purposes.Science, medicine, and engineering often use larger and smaller units of measurement than those used in everyday life. The judicious selection of the units of measurement can aid researchers in problem solving (see, for example, dimensional analysis). In the social sciences, there are no standard units of measurement and the theory and practice of measurement is studied in psychometrics and the theory of conjoint measurement.
Model-dependent realism Overview Model-dependent_realism > Overview Model-dependent realism asserts that all we can know about "reality" consists of networks of world pictures that explain observations by connecting them by rules to concepts defined in models. Will an ultimate theory of everything be found? Hawking and Mlodinow suggest it is unclear: In the history of science we have discovered a sequence of better and better theories or models, from Plato to the classical theory of Newton to modern quantum theories.
Aglycone Clinical significance Aglycone > Clinical significance A study on molecular markers in human aortic endothelial cells published that aglycone stopped cell migration but not monocyte adhesion, which is the initial step of atherosclerotic plaque formation. Another study exploring the benefits of extra virgin olive oil consumption in preventing age-related neurodegenerative diseases found aglycone greatly increased the cognitive performance of mice. The aglycone-fed mice displayed strong autophagic reactions, mTOR regulation, and reduced plaque deposits and ß-amyloid levels.
T helper cell Hypersensitivity CD4(+)_T_cell > Role in disease > Hypersensitivity Many auto-immune diseases are more complex. A well-known example is rheumatoid arthritis, where both antibodies and immune cells are known to play a role in the pathology. Generally the immunology of most auto-immune diseases is not well understood.
Artificial enzyme History Artificial_enzyme > History Classically, artificial enzymes bind substrates using receptors such as cyclodextrin, crown ethers, and calixarene.Artificial enzymes based on amino acids or peptides have expanded the field of artificial enzymes or enzyme mimics. For instance, scaffolded histidine residues mimic certain metalloproteins and enzymes such as hemocyanin, tyrosinase, and catechol oxidase).Artificial enzymes have been designed from scratch via a computational strategy using Rosetta. A December 2014 publication reported active enzymes made from molecules that do not occur in nature. In 2016, a book chapter entitled "Artificial Enzymes: The Next Wave" was published.
Etomidate Adverse effects Etomidate > Adverse effects Etomidate suppresses corticosteroid synthesis in the adrenal cortex by reversibly inhibiting 11β-hydroxylase, an enzyme important in adrenal steroid production; it leads to primary adrenal suppression. Using a continuous etomidate infusion for sedation of critically ill trauma patients in intensive care units has been associated with increased mortality due to adrenal suppression. Continuous intravenous administration of etomidate leads to adrenocortical dysfunction. The mortality of patients exposed to a continuous infusion of etomidate for more than 5 days increased from 25% to 44%, mainly due to infectious causes such as pneumonia.Because of etomidate-induced adrenal suppression, its use for patients with sepsis is controversial.
Real vector Hilbert spaces Coordinate_vector_space > Vector spaces with additional structure > Topological vector spaces > Hilbert spaces More generally, and more conceptually, the theorem yields a simple description of what "basic functions", or, in abstract Hilbert spaces, what basic vectors suffice to generate a Hilbert space H , {\displaystyle H,} in the sense that the closure of their span (that is, finite linear combinations and limits of those) is the whole space. Such a set of functions is called a basis of H , {\displaystyle H,} its cardinality is known as the Hilbert space dimension. Not only does the theorem exhibit suitable basis functions as sufficient for approximation purposes, but also together with the Gram–Schmidt process, it enables one to construct a basis of orthogonal vectors.
Normality (behavior) DSM Normality_(behavior) > Clinical normality > DSM Normality, as a relative concept, is intrinsically involved with contextual elements. As a result, clinical disorder classification has particular challenges in discretely diagnosing 'normal' constitutions from true disorders. The Diagnostic and Statistical Manual of Mental Disorders (DSM) is the psychiatric profession's official classification manual of mental disorders since its first published version (DSM-I) by the American Psychological Association in 1952. As the DSM evolved into its current version (DSM-V) in late 2013, there have been numerous conflicts in proposed classification between mental illness and normal mentality.
Sulfate-reducing microorganisms Summary Sulfate-reducing_bacteria Sulfate-reducing microorganisms (SRM) or sulfate-reducing prokaryotes (SRP) are a group composed of sulfate-reducing bacteria (SRB) and sulfate-reducing archaea (SRA), both of which can perform anaerobic respiration utilizing sulfate (SO2−4) as terminal electron acceptor, reducing it to hydrogen sulfide (H2S). Therefore, these sulfidogenic microorganisms "breathe" sulfate rather than molecular oxygen (O2), which is the terminal electron acceptor reduced to water (H2O) in aerobic respiration. Most sulfate-reducing microorganisms can also reduce some other oxidized inorganic sulfur compounds, such as sulfite (SO2−3), dithionite (S2O2−4), thiosulfate (S2O2−3), trithionate (S3O2−6), tetrathionate (S4O2−6), elemental sulfur (S8), and polysulfides (S2−n). Other than sulfate reduction, some sulfate-reducing microorganisms are also capable of other reactions like disproportionation of sulfur compounds.
Glossary of mycology M Glossary_of_mycology > M The plant disease caused by such fungi. mitosis The normal division of a nucleus. Results in two child nuclei with the same number of chromosomes as the parent.
Meridian distance Series expansions Arc_of_the_meridian > Calculation > Series expansions The above integral may be expressed as an infinite truncated series by expanding the integrand in a Taylor series, performing the resulting integrals term by term, and expressing the result as a trigonometric series. In 1755, Leonhard Euler derived an expansion in the third eccentricity squared.
Molar mass constant Summary Molar_mass_constant Thus, for example, the average atomic mass of chlorine is approximately 35.446 daltons, making the mass of one mole of chlorine atoms approximately 35.446 grams. On 20 May 2019, the SI definition of mole changed in such a way that the molar mass constant remains nearly but no longer exactly 1 g/mol.
Reaction (physics) Mass on a spring Reaction_force > Examples > Mass on a spring The gravitational force pulling down on the mass is no longer equal to the upward elastic force of the spring. In the terminology of the previous section, F1 and F3 are no longer equal. However, it is still true that F1 = F2 and F3 = F4, as this is required by Newton's third law.
X-Ray Diffraction Pattern X-ray diffraction X-Ray_Crystallography > History > X-ray diffraction The idea that crystals could be used as a diffraction grating for X-rays arose in 1912 in a conversation between Paul Peter Ewald and Max von Laue in the English Garden in Munich. Ewald had proposed a resonator model of crystals for his thesis, but this model could not be validated using visible light, since the wavelength was much larger than the spacing between the resonators. Von Laue realized that electromagnetic radiation of a shorter wavelength was needed to observe such small spacings, and suggested that X-rays might have a wavelength comparable to the unit-cell spacing in crystals.
Short hundred In mathematics Short_hundred > In mathematics It is the 10th star number (whose digit sum also adds to 10 in decimal). There are exactly 100 prime numbers in base-ten whose digits are in strictly ascending order (e.g. 239, 2357 etc.). The last such prime number is 23456789, which contains eight consecutive integers as digits.
Immortal DNA strand hypothesis Mechanisms Immortal_DNA_strand_hypothesis > Mechanisms The complete proof of a concept generally requires a plausible mechanism that could mediate the effect. Although controversial, there is a suggestion that this could be provided by the Dynein Motor. This paper is accompanied by a comment summarizing the findings and background.However, this work has highly respected biologists among its detractors as exemplified by a further comment on a paper by the same authors from 2006. The authors have rebutted the criticism.
Data Protection Internet Data_Protection > Information types > Internet In an age where increasing amounts of information is online, social networking sites pose additional privacy challenges. People may be tagged in photos or have valuable information exposed about themselves either by choice or unexpectedly by others, referred to as participatory surveillance. Data about location can also be accidentally published, for example, when someone posts a picture with a store as a background.
Burroughs large systems Stack architecture Burroughs_large_systems > Stack architecture In many early systems and languages, programmers were often told not to make their routines too small. Procedure calls and returns were expensive, because a number of operations had to be performed to maintain the stack. The B5000 was designed as a stack machine – all program data except for arrays (which include strings and objects) was kept on the stack. This meant that stack operations were optimized for efficiency.
Remote sensing satellites Data processing Earth_remote_sensing > Data processing The common analogy given to describe this is trying to determine the type of animal from its footprints. For example, while it is impossible to directly measure temperatures in the upper atmosphere, it is possible to measure the spectral emissions from a known chemical species (such as carbon dioxide) in that region. The frequency of the emissions may then be related via thermodynamics to the temperature in that region.
Transformer (neural network) Predecessors Transformer_(machine_learning_model) > Timeline > Predecessors Before transformers, predecessors of attention mechanism were added to gated RNNs, such as LSTMs and gated recurrent units (GRUs), which processed datasets sequentially. Dependency on previous token computations prevented them from being able to parallelize the attention mechanism. In 1992, fast weight controller was proposed as an alternative to RNNs that can learn "internal spotlights of attention". In theory, the information from one token can propagate arbitrarily far down the sequence, but in practice the vanishing gradient problem leaves the model's state at the end of a long sentence without precise, extractable information about preceding tokens.
Wallerian degeneration Summary Wallerian_degeneration Axonal degeneration is followed by degradation of the myelin sheath and infiltration by macrophages. The macrophages, accompanied by Schwann cells, serve to clear the debris from the degeneration.Schwann cells respond to loss of axons by extrusion of their myelin sheaths, downregulation of myelin genes, dedifferentiation and proliferation. They finally align in tubes (Büngner bands) and express surface molecules that guide regenerating fibers.
Exaptation Evolution of complex traits Exaptation > Implications > Evolution of complex traits By trapping air, primitive wings would have enabled birds to efficiently regulate their temperature, in part, by lifting up their feathers when too warm. Individual animals with more of this functionality would more successfully survive and reproduce, resulting in the proliferation and intensification of the trait. Eventually, feathers became sufficiently large to enable some individuals to glide. These individuals would in turn more successfully survive and reproduce, resulting in the spread of this trait because it served a second and still more beneficial function: that of locomotion. Hence, the evolution of bird wings can be explained by a shifting in function from the regulation of temperature to flight.
COVID-19 and cancer Long COVID-19 COVID-19_and_cancer > Long COVID-19 Even though many COVID-19 patients recover within 2–6 weeks of the onset of symptoms, some develop symptoms that come and go for months. The possibility has been raised, but needs to be investigated further, that patients with long COVID-19 may be predisposed to the development of lung cancer. == References ==
Combinatorial optimisation NP optimization problem Combinatorial_Optimization > NP optimization problem Contains the Makespan scheduling problem. NPO(III): :The class of NPO problems that have polynomial-time algorithms which computes solutions with a cost at most c times the optimal cost (for minimization problems) or a cost at least 1 / c {\displaystyle 1/c} of the optimal cost (for maximization problems).
Glossary of aerospace engineering G Glossary_of_aerospace_engineering > G Glide ratio – As the aircraft fuselage and control surfaces will also add drag and possibly some lift, it is fair to consider the lift-to-drag ratio (or L/D ratio) of the aircraft as a whole. As it turns out, the glide ratio, which is the ratio of an (unpowered) aircraft's forward motion to its descent, is (when flown at constant speed) numerically equal to the aircraft's L/D. This is especially of interest in the design and operation of high performance sailplanes, which can have glide ratios almost 60 to 1 (60 units of distance forward for each unit of descent) in the best cases, but with 30:1 being considered good performance for general recreational use.
Synizesis (biology) Summary Synizesis_(biology) Synizesis refers to a phenomenon sometimes observed in one of the subphases of meiosis. This phenomenon, sometimes referred to as a "synizetic knot", and contrasted with the chromosome "bouquet" more typically observed, is characterized by the localization of the meiotic chromosomes in a tight clump on one side of the nucleus. The term synizesis seems to have been coined by Clarence Erwin McClung in 1905.The synizetic knot (Synizesis) was later found to be a technical artifact induced by the feature of strong acidic fixatives used during that time (e.g., Flemming's strong fixative) to precipitate the thread-like delicate chromosomes of the Leptotene stage of first meiotic prophase into a dark staining knot. == References ==
Reachability problem Summary Reachability_problem Reachability is a fundamental problem that appears in several different contexts: finite- and infinite-state concurrent systems, computational models like cellular automata and Petri nets, program analysis, discrete and continuous systems, time critical systems, hybrid systems, rewriting systems, probabilistic and parametric systems, and open systems modelled as games.In general the reachability problem can be formulated as follows: Given a computational (potentially infinite state) system with a set of allowed rules or transformations, decide whether a certain state of a system is reachable from a given initial state of the system. Variants of the reachability problem may result from additional constraints on the initial or final states, specific requirement for reachability paths as well as for iterative reachability or changing the questions into analysis of winning strategies in infinite games or unavoidability of some dynamics. Typically, for a fixed system description given in some form (reduction rules, systems of equations, logical formulas, etc.) a reachability problem consists of checking whether a given set of target states can be reached starting from a fixed set of initial states. The set of target states can be represented explicitly or via some implicit representation (e.g., a system of equations, a set of minimal elements with respect to some ordering on the states).
Flood fill Advantages Flood_fill > Stack-based recursive implementation (four-way) > Advantages Very simple algorithm - easy to make bug-free.
Sorted array Overview Sorted_array > Overview If one is using a sorted dynamic array, then it is possible to insert and delete elements. The insertion and deletion of elements in a sorted array executes at O(n), due to the need to shift all the elements following the element to be inserted or deleted; in comparison a self-balancing binary search tree inserts and deletes at O(log n). In the case where elements are deleted or inserted at the end, a sorted dynamic array can do this in amortized O(1) time while a self-balancing binary search tree always operates at O(log n). Elements in a sorted array can be looked up by their index (random access) at O(1) time, an operation taking O(log n) or O(n) time for more complex data structures.
Analytic Fredholm theorem Summary Analytic_Fredholm_theorem In mathematics, the analytic Fredholm theorem is a result concerning the existence of bounded inverses for a family of bounded linear operators on a Hilbert space. It is the basis of two classical and important theorems, the Fredholm alternative and the Hilbert–Schmidt theorem. The result is named after the Swedish mathematician Erik Ivar Fredholm.
Ionic polarization Some practical dielectrics Dielectric_properties > Some practical dielectrics This can be useful, as in a Van de Graaff generator or electrophorus, or it can be potentially destructive as in the case of electrostatic discharge. Specially processed dielectrics, called electrets (which should not be confused with ferroelectrics), may retain excess internal charge or "frozen in" polarisation. Electrets have a semi-permanent electric field, and are the electrostatic equivalent to magnets.
First cosmic speed Trajectory Earth_escape_velocity > Trajectory A relatively small extra delta-v above that needed to accelerate to the escape speed can result in a relatively large speed at infinity. Some orbital manoeuvres make use of this fact. For example, at a place where escape speed is 11.2 km/s, the addition of 0.4 km/s yields a hyperbolic excess speed of 3.02 km/s: v ∞ = V 2 − v e 2 = ( 11.6 km/s ) 2 − ( 11.2 km/s ) 2 ≈ 3.02 km/s .
Evolutionary process Heredity Evolutionary_process > Heredity DNA sequences can change through mutations, producing new alleles. If a mutation occurs within a gene, the new allele may affect the trait that the gene controls, altering the phenotype of the organism. However, while this simple correspondence between an allele and a trait works in some cases, most traits are influenced by multiple genes in a quantitative or epistatic manner.
Ideal mechanical advantage Chain and belt drives Ideal_mechanical_advantage > Chain and belt drives The mechanical advantage of a pair of a chain drive or toothed belt drive with an input sprocket with NA teeth and the output sprocket has NB teeth is given by M A = T B T A = N B N A . {\displaystyle {\mathit {MA}}={\frac {T_{B}}{T_{A}}}={\frac {N_{B}}{N_{A}}}.} The mechanical advantage for friction belt drives is given by M A = T B T A = r B r A .
Plotly Data visualization libraries Plotly > Data visualization libraries Plotly provides a collection of supported chart types across several programming languages:
Autostereogram Terminology Autostereogram > Terminology When the single 2D image is viewed with proper eye convergence, it causes the brain to fuse different patterns perceived by the two eyes into a virtual 3D image without, hidden within the 2D image, the aid of any optical equipment. SIS images are created using a repeating pattern. Programs for their creation include Mathematica.Random dot autostereogram/hidden image stereogramIs also known as single image random dot stereogram (SIRDS). This term also refers to autostereograms where the hidden 3D image is created using a random pattern of dots within one image, shaped by a depth map within a dedicated stereogram rendering program.Wallpaper autostereogram/object array stereogram/texture offset stereogramWallpaper autostereogram is a single 2D image where recognizable patterns are repeated at various intervals to raise or lower each pattern's perceived 3D location in relation to the display surface. Despite the repetition, these are a type of single image autostereogram.Single image random text stereogram (SIRTS)A single image random text ASCII stereogram is an alternative to SIRDS using random ASCII text instead of dots to produce a 3D form of ASCII art.Map textured stereogramIn a map textured stereogram, "a fitted texture is mapped onto the depth image and repeated a number of times" resulting in a pattern where the resulting 3D image is often partially or fully visible before viewing.
Baryonic matter Flavour quantum numbers Baryon > Properties > Flavour quantum numbers Since only the u and d mass are similar, this description of particle mass and charge in terms of isospin and flavour quantum numbers works well only for octet and decuplet made of one u, one d, and one other quark, and breaks down for the other octets and decuplets (for example, ucb octet and decuplet). If the quarks all had the same mass, their behaviour would be called symmetric, as they would all behave in the same way to the strong interaction. Since quarks do not have the same mass, they do not interact in the same way (exactly like an electron placed in an electric field will accelerate more than a proton placed in the same field because of its lighter mass), and the symmetry is said to be broken.
Human flight Wright brothers Human_flight > Heavier than air > Wright brothers They almost doubled the size of the elevator and rudder and moved them about twice the distance from the wings. They added two fixed vertical vanes (called "blinkers") between the elevators and gave the wings a very slight dihedral. They disconnected the rudder from the wing-warping control, and as in all future aircraft, placed it on a separate control handle.
Secondary Causation Summary Secondary_Causation Secondary causation is the philosophical proposition that all material and corporeal objects, having been created by God with their own intrinsic potentialities, are subsequently empowered to evolve independently in accordance with natural law. Traditional Christians would slightly modify this injunction to allow for the occasional miracle as well as the exercise of free will. Deists who deny any divine interference after creation would only accept free will exceptions. That the physical universe is consequentially well-ordered, consistent, and knowable, subject to human observation and reason, was a primary theme of Scholasticism and further molded into the philosophy of the western tradition by Augustine of Hippo and later by Thomas Aquinas.

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