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GalP (protein) Homeostasis GalP_(protein) > Homeostasis The GalP symporter links galactose and proton import, using the favorable proton concentration gradient to move galactose against its concentration gradient. However, this mechanism, if in isolation, would result in acidification of the cytoplasm and cessation of galactose import(14). To prevent this, E. coli utilizes ion pumps designed to raise intracellular pH (13,14). During electron transport (a key step in ATP production in respiration), energy harnessed from electrons is used to pump protons into the periplasmic space to build a proton motive force.
Mental energy Neurotransmitter Mental_energy > Neurotransmitter Many different neurotransmitters have been theoretically implicated in the control of mental energy. This has often been based on the effects of drugs acting on these neurotransmitters. These neurotransmitters include dopamine, norepinephrine, orexin, serotonin, histamine, acetylcholine, adenosine, and glutamate. Hormones, including glucocorticoids like cortisol, as well as cytokines, have also been found to regulate mental energy.
Model trains Scratch building Model_railroading > Scratch building Laser machining techniques have extended this ability to thicker materials for scale steam and other locomotive types. Scratch builders may also make silicone rubber moulds of the parts they create, and cast them in various plastic resins (see Resin casting), or plasters. This may be done to save duplication of effort, or to sell to others. Resin "craftsman kits" are also available for a wide range of prototypes.
Hardware-in-the-loop simulation Uses Hardware-in-the-loop_simulation > Uses In many cases, the most effective way to develop an embedded system is to connect the embedded system to the real plant. In other cases, HIL simulation is more efficient. The metric of development and testing efficiency is typically a formula that includes the following factors: 1.
Structural engineering theory Euler–Bernoulli beam equation Structural_engineering_theory > Euler–Bernoulli beam equation The Euler–Bernoulli beam equation defines the behaviour of a beam element (see below). It is based on five assumptions: Continuum mechanics is valid for a bending beam. The stress at a cross section varies linearly in the direction of bending, and is zero at the centroid of every cross section.
Law of superposition General sources Law_of_superposition > References > General sources Hamblin, W.K. The Earth's Dynamic Systems: A Textbook in Physical Geology, by W. Kenneth Hamblin, BYU, Provo, UT, Illus. William L. Chesser, Dennis Tasa, (Burgess Publishing Company, Minneapolis, Minnesota), c 1978, pg. 115, "The Principle of Superposition and Original Horizontality;" pg.
Decentralized information technology History Decentralized_information_technology > History These include, for example, the growing distrust of government generally, the spectacular demise of some of the most centralized regimes in the world (especially the Soviet Union) and the emerging separatist demands that seem to routinely pop up in one or another part of the world. The movement toward local accountability and greater control over one's destiny is, however, not solely the result of the negative attitude towards central government. Rather, these developments, as we have already noted, are principally being driven by a strong desire for greater participation of citizens and private sector organizations in governance."
Complete metric Some theorems Complete_metric > Some theorems That is, the union of countably many nowhere dense subsets of the space has empty interior. The Banach fixed-point theorem states that a contraction mapping on a complete metric space admits a fixed point. The fixed-point theorem is often used to prove the inverse function theorem on complete metric spaces such as Banach spaces.
Pi interaction π-effects in biological systems Pi-interaction > π-effects in biological systems The nucleophile can be any of a broad range structures including nucleic acids, proteins, sugars or C=C bond of lipids or steroids. The van der Waals contact between S-CH3 unit of SAM and the aromatic face of a Trp residue, in favorable alignment for catalysis assisted by cation-π interaction. A great deal of circumstantial evidence places aromatic residues in the active site of a number of proteins that interact with cations but the presence of cation-π interaction in biological system does not rule out the conventional ion-pair interaction. In fact there is a good evidence for the existence of both type of interaction in model system.
Stochastic gradient descent History Stochastic_gradient_descent > History SGD was gradually developed by several collectives during the 1950s. The scaling behavior of SGD (i.e. how the performance evaluation metric of interest (e.g. test loss) varies as the number of training steps varies) was found to follow a broken neural scaling law functional form in 2022.
Quantization noise Uniform quantization and the 6 dB/bit approximation Quantization_noise > Design > Uniform quantization and the 6 dB/bit approximation The property of 6 dB improvement in SQNR for each extra bit used in quantization is a well-known figure of merit. However, it must be used with care: this derivation is only for a uniform quantizer applied to a uniform source. For other source PDFs and other quantizer designs, the SQNR may be somewhat different from that predicted by 6 dB/bit, depending on the type of PDF, the type of source, the type of quantizer, and the bit rate range of operation.
Variable-speed drive Acceleration control Variable_speed_drives > Reasons for using adjustable speed drives > Acceleration control An adjustable speed drive can often provide smoother operation compared to an alternative fixed speed mode of operation. For example, in a sewage lift station sewage usually flows through sewer pipes under the force of gravity to a wet well location. From there it is pumped up to a treatment process. When fixed speed pumps are used, the pumps are set to start when the level of the liquid in the wet well reaches some high point and stop when the level has been reduced to a low point.
Area (geometry) Circles Area_(geometry) > Area formulas > Area of curved shapes > Circles Thus, the total area of the circle is πr2: A = πr2 (circle).Though the dissection used in this formula is only approximate, the error becomes smaller and smaller as the circle is partitioned into more and more sectors. The limit of the areas of the approximate parallelograms is exactly πr2, which is the area of the circle.This argument is actually a simple application of the ideas of calculus.
Permutation (music) Summary Permutation_(music) To receive the inversion of any prime, each number value is subtracted from 12 and the resulting number placed in the corresponding matrix cell (see twelve-tone technique). The retrograde inversion is the values of the inversion numbers read backwards. Therefore: A given prime zero (derived from the notes of Anton Webern's Concerto): 0, 11, 3, 4, 8, 7, 9, 5, 6, 1, 2, 10 The retrograde: 10, 2, 1, 6, 5, 9, 7, 8, 4, 3, 11, 0 The inversion: 0, 1, 9, 8, 4, 5, 3, 7, 6, 11, 10, 2 The retrograde inversion: 2, 10, 11, 6, 7, 3, 5, 4, 8, 9, 1, 0 More generally, a musical permutation is any reordering of the prime form of an ordered set of pitch classes or, with respect to twelve-tone rows, any ordering at all of the set consisting of the integers modulo 12.
Social discovery platform Developments Social_search_engine > Developments The security concerns can be classified into three categories: data privacy, data integrity and secure social search. Data privacy protection is defined as the way users can fully control their data and manage its accessibility. The solutions for data privacy include information substitution, attributed based encryption and identity based broadcast encryption.
Renal osteodystrophy Prognosis Renal_osteodystrophy > Prognosis Recovery from renal osteodystrophy has been observed following kidney transplantation. Renal osteodystrophy is a chronic condition with a conventional hemodialysis schedule. Nevertheless, it is important to consider that the broader concept of CKD-MBD, which includes renal osteodystrophy, is not only associated with bone disease and increased risk of fractures but also with cardiovascular calcification, poor quality of life and increased morbidity and mortality in CKD patients (the so-called bone-vascular axis). Actually, bone may now be considered a new endocrine organ at the heart of CKD-MBD.
Naive Set Theory (book) Summary Naive_Set_Theory_(book) See also Naive set theory for the mathematical topic.Naive Set Theory is a mathematics textbook by Paul Halmos providing an undergraduate introduction to set theory. Originally published by Van Nostrand in 1960, it was reprinted in the Springer-Verlag Undergraduate Texts in Mathematics series in 1974.While the title states that it is naive, which is usually taken to mean without axioms, the book does introduce all the axioms of ZFC set theory (except the Axiom of Foundation), and gives correct and rigorous definitions for basic objects. Where it differs from a "true" axiomatic set theory book is its character: there are no discussions of axiomatic minutiae, and there is next to nothing about advanced topics like large cardinals. Instead, it tries to be intelligible to someone who has never thought about set theory before. Halmos later stated that it was the fastest book he wrote, taking about six months, and that the book "wrote itself".
Autoantigen Sex Autoantigen > Sex Involvement of sex steroids is indicated by that many autoimmune diseases tend to fluctuate in accordance with hormonal changes, for example: during pregnancy, in the menstrual cycle, or when using oral contraception. A history of pregnancy also appears to leave a persistent increased risk for autoimmune disease. It has been suggested that the slight, direct exchange of cells between mothers and their children during pregnancy may induce autoimmunity.
Optimistic locking Summary Optimistic_locking If the check reveals conflicting modifications, the committing transaction rolls back and can be restarted. Optimistic concurrency control was first proposed in 1979 by H. T. Kung and John T. Robinson.OCC is generally used in environments with low data contention. When conflicts are rare, transactions can complete without the expense of managing locks and without having transactions wait for other transactions' locks to clear, leading to higher throughput than other concurrency control methods. However, if contention for data resources is frequent, the cost of repeatedly restarting transactions hurts performance significantly, in which case other concurrency control methods may be better suited. However, locking-based ("pessimistic") methods also can deliver poor performance because locking can drastically limit effective concurrency even when deadlocks are avoided.
Beneficial AI Risks of unfriendly AI Friendly_artificial_intelligence > Risks of unfriendly AI The roots of concern about artificial intelligence are very old. Kevin LaGrandeur showed that the dangers specific to AI can be seen in ancient literature concerning artificial humanoid servants such as the golem, or the proto-robots of Gerbert of Aurillac and Roger Bacon. In those stories, the extreme intelligence and power of these humanoid creations clash with their status as slaves (which by nature are seen as sub-human), and cause disastrous conflict. By 1942 these themes prompted Isaac Asimov to create the "Three Laws of Robotics"—principles hard-wired into all the robots in his fiction, intended to prevent them from turning on their creators, or allowing them to come to harm.In modern times as the prospect of superintelligent AI looms nearer, philosopher Nick Bostrom has said that superintelligent AI systems with goals that are not aligned with human ethics are intrinsically dangerous unless extreme measures are taken to ensure the safety of humanity.
Electronic configuration Other exceptions to Madelung's rule Electron_configurations > Atoms: Aufbau principle and Madelung rule > Other exceptions to Madelung's rule There are several more exceptions to Madelung's rule among the heavier elements, and as atomic number increases it becomes more and more difficult to find simple explanations such as the stability of half-filled subshells. It is possible to predict most of the exceptions by Hartree–Fock calculations, which are an approximate method for taking account of the effect of the other electrons on orbital energies. Qualitatively, for example, the 4d elements have the greatest concentration of Madelung anomalies, because the 4d–5s gap is larger than the 3d–4s and 5d–6s gaps.For the heavier elements, it is also necessary to take account of the effects of special relativity on the energies of the atomic orbitals, as the inner-shell electrons are moving at speeds approaching the speed of light. In general, these relativistic effects tend to decrease the energy of the s-orbitals in relation to the other atomic orbitals.
Biocybernetics Similar fields Biocybernetics > Similar fields Papers and research that delve into topics involving biocybernetics may be found under a multitude of similar names, including molecular cybernetics, neurocybernetics, and cellular cybernetics. Such fields involve disciplines that specify certain aspects of the study of the living organism (for example, neurocybernetics focuses on the study neurological models in organisms).
Orthodontic archwire Terms used in defining wires Orthodontic_archwire > Terms used in defining wires Stress - Internal distribution of load Strain - Internal distortion produced by the load Proportional limit - A point at which first permanent deformation is observed Yield strength - At this point, an orthodontic wire will not return to its original shape Ultimate tensile strength - The maximum load a wire can sustain Failure point - A point at which a wire breaks Modulus of elasticity - It is the ratio between stress and strain. It is measured by the slope of the elastic region. It describes the stiffness or rigidity of the material Load-Deflection Rate - It is defined as for a given load/force, the amount of deflection observed is known as the load deflection rate Stiffness - The slope of a stress/strain graph of an orthodontic wires is proportional to the stiffness of a wire. The higher the slope, the higher the stiffness.
Comparative diagram Overview Comparison_diagram > Overview A comparison diagram is a general type of diagram, meaning a class of specific diagrams and charts, in which a comparison is made between two or more objects, phenomena or groups of data. They are a tool for visual comparison. When it comes to comparing data, five basic types of comparison can be determined. Comparison of components, for example the pieces of pie chart Item comparison, for example the bars in a bar chart Time-series comparison, for example the bars in a histogram or the curve of a line chart Frequency distribution comparison, for example the distribution in a histogram or line chart Correlation comparison, for example in a specific dot diagramComparison diagrams can be used in research projects, to give an overview of existing possibilities and to validate models. It can be used in decision making in presenting alternatives for further selection. And it can be used in education to show the variety in a specific population.
Adversarial machine learning HopSkipJump Attack General_adversarial_network > Specific attack types > Adversarial examples > Black box attacks > HopSkipJump Attack The next step involves calculating the gradient for x {\textstyle x} , and update the original x {\textstyle x} using this gradient and a pre-chosen step size. HopSkipJump authors prove that this iterative algorithm will converge, leading x {\textstyle x} to a point right along the boundary that is very close in distance to the original image.However, since HopSkipJump is a proposed black box attack and the iterative algorithm above requires the calculation of a gradient in the second iterative step (which black box attacks do not have access to), the authors propose a solution to gradient calculation that requires only the model's output predictions alone. By generating many random vectors in all directions, denoted as u b {\textstyle u_{b}} , an approximation of the gradient can be calculated using the average of these random vectors weighted by the sign of the boundary function on the image x ′ + δ u b {\textstyle x^{\prime }+\delta _{u_{b}}} , where δ u b {\textstyle \delta _{u_{b}}} is the size of the random vector perturbation: The result of the equation above gives a close approximation of the gradient required in step 2 of the iterative algorithm, completing HopSkipJump as a black box attack.
Observer effect (physics) Particle physics Observer_effect_(physics) > Particle physics An electron is detected upon interaction with a photon; this interaction will inevitably alter the velocity and momentum of that electron. It is possible for other, less direct means of measurement to affect the electron. It is also necessary to distinguish clearly between the measured value of a quantity and the value resulting from the measurement process.
Filter strip Summary Filter_strip In agriculture, they are highly effective in reducing the concentration of nitrogen (N) and phosphorus (P) in runoff into surface water and are also effective in reducing sediment erosion and removing pesticides. This helps to prevent eutrophication and associated fishkills and loss of biodiversity. The use of filter strips is very common in developed countries and is required by law in some areas. The implementation and maintenance of filter strips is inexpensive and their use has been shown to be cost effective.
Nelson Complexity Index Complexity factors Nelson_Complexity_Index > Complexity factors Some factors for various processing units:
Ecosystem respiration Importance Ecosystem_respiration > Importance The evolution of oxygenic photosynthesis in the atmosphere amplified the productivity of the biosphere, increasing biodiversity. With the presence of photosynthesis providing oxygen to the atmosphere, respiration soon evolved to provide the necessary components photosynthesis demanded to function. This coevolution of photosynthesis and respiration processes has led us to the biodiverse and fruitful ecosystems we know today.
Coxeter notation Rank three groups Coxeter_notation > Rank three groups In all these symmetries, alternate reflections can be removed producing the rotational tetrahedral +(), octahedral + (), and icosahedral + () groups of order 12, 24, and 60. The octahedral group also has a unique index 2 subgroup called the pyritohedral symmetry group, ( or ), of order 12, with a mixture of rotational and reflectional symmetry. Pyritohedral symmetry is also an index 5 subgroup of icosahedral symmetry: --> , with virtual mirror 1 across 0, {010}, and 3-fold rotation {12}. The tetrahedral group, (), has a doubling ] (which can be represented by colored nodes ), mapping the first and last mirrors onto each other, and this produces the ( or ) group. The subgroup ( or ) is the same as , and ( or ) is the same as +.
List of equations in quantum mechanics Summary List_of_equations_in_quantum_mechanics This article summarizes equations in the theory of quantum mechanics.
Social constructivism (learning theory) Responsibility for learning Constructivist_learning > Individual > Constructivist learning intervention > The nature of the learner > Responsibility for learning Furthermore, it is argued that the responsibility of learning should reside increasingly with the student. Social constructivism thus emphasizes the importance of the student being actively involved in the learning process, unlike previous educational viewpoints where the responsibility rested with the instructor to teach and where the learner played a passive, receptive role. Von Glasersfeld (1989) emphasized that learners construct their own understanding and that they do not simply mirror and reflect what they read. Learners look for meaning and will try to find regularity and order in the events of the world even in the absence of full or complete information.
Data model diagram Database model Data_models > Types > Database model The power of the relational data model lies in its mathematical foundations and a simple user-level paradigm. Object–relational model Similar to a relational database model, but objects, classes, and inheritance are directly supported in database schemas and in the query language. Object–role modeling A method of data modeling that has been defined as "attribute free", and "fact-based".
Operational modal analysis Operational modal analysis versus operational deflection shape Operational_modal_analysis > Operational modal analysis versus operational deflection shape The two terms, Operational Modal Analysis and Operational Deflection Shape, are very similar, but refer to two different analysis approaches. Both use ambient vibration data as inputs, but in the case of Operational Deflection Shapes, a shape that corresponds to the overall vibration response is created. It is based on the vibration amplitude only, there is no attempt to extract a mode shape and no quantification of the modal damping can be obtained. While Operational Modal Analysis, when the main assumptions are met, yields a representation of a system characteristic in its operating environment, an Operational Deflection Shape will simply extract the system response under the currently applied loads.
Experimental physicist History Experimental_Physics > History As a distinct field, experimental physics was established in early modern Europe, during what is known as the Scientific Revolution, by physicists such as Galileo Galilei, Christiaan Huygens, Johannes Kepler, Blaise Pascal and Sir Isaac Newton. In the early 17th century, Galileo made extensive use of experimentation to validate physical theories, which is the key idea in the modern scientific method. Galileo formulated and successfully tested several results in dynamics, in particular the law of inertia, which later became the first law in Newton's laws of motion. In Galileo's Two New Sciences, a dialogue between the characters Simplicio and Salviati discuss the motion of a ship (as a moving frame) and how that ship's cargo is indifferent to its motion.
Zero-ohm link Use Zero_ohm_resistor > Use A percentage tolerance would not make sense, as it would be specified as a percentage of the ideal value of zero ohms (which would always be zero).An axial-lead through-hole zero-ohm resistor is generally marked with a single black band, the symbol for "0" in the resistor color code. Surface-mount zero-ohm resistors are usually marked with a single or multiple "0" (if size allows marking), where the number of digits can indicate the tolerance or maximum resistance rating, as is the case with regular resistors. They are often implemented as thick film resistors.
Mitochondrial fission FtsZ Localization Mitochondrial_fission > Mechanism > FtsZ Localization The FtsZ protein (a homologue to eukaryotic tubulin), found in many bacteria and some archaea, plays a role in mitochondrial fission. The Min system plays a role in localizing and assembling FtsZ proteins into a ring around the center of the mitochondria and some proteins tethered to the inner mitochondrial membrane also help anchor the Z ring. The Z ring is anchored at the site of constriction where division will take place. The Z ring acts as a scaffold for the deposition of septum, and it is aided in this by the proteins by FtsW, FtsI and FtsN. The translocase FtsK helps move the mtDNA away from the site of constriction.
Impulse excitation technique Extended IET for orthotropic material behaviour Impulse_excitation_technique > Extended IET applications: the Resonalyser Method > Extended IET for orthotropic material behaviour The interesting property of a Freely suspended Poisson plate is that the modal shapes that are associated with the 3 first resonance frequencies are fixed: the first resonance frequency is associated with a torsional modal shape, the second resonance frequency is associated with a saddle modal shape and the third resonance frequency is associated with a breathing modal shape. So, without the necessity to do an investigation to the nature of the modal shapes, the IET on a Poisson plate reveals the vibrational behaviour of a Poisson plate. The question is now how to extract the orthotropic Engineering constants from the frequencies measured with IET on the beams and Poisson plate.
Gilbert Froment Key publications Gilbert_Froment > Key publications (1982). "Reforming of C6 hydrocarbons on a Pt/Al2O3 catalyst". Chemical Engineering Science.
Entropy of activation Summary Entropy_of_activation In chemical kinetics, the entropy of activation of a reaction is one of the two parameters (along with the enthalpy of activation) which are typically obtained from the temperature dependence of a reaction rate constant, when these data are analyzed using the Eyring equation of the transition state theory. The standard entropy of activation is symbolized ΔS‡ and equals the change in entropy when the reactants change from their initial state to the activated complex or transition state (Δ = change, S = entropy, ‡ = activation).
Edward Bernays Selected articles Edward_Bernays > Publications > Selected articles Annals of the American Academy of Political and Social Science, vol. 250 (Mar. 1947).
Watering garden Design Watering_garden > Design Constructed elements include paths, patios, decking, sculptures, drainage systems, lights and buildings (such as sheds, gazebos, pergolas and follies), but also living constructions such as flower beds, ponds and lawns. Consideration is also given to the maintenance needs of the garden. Including the time or funds available for regular maintenance, (this can affect the choices of plants regarding speed of growth) spreading or self-seeding of the plants (annual or perennial), bloom-time, and many other characteristics.
Dehumidifier Refrigeration (electric) Dehumidifier > Thermal condensation dehumidification > Refrigeration (electric) Fresh air is then introduced to replace the amount that was extracted and the mix is discharged by the supply fan (G) to the crossflow plate exchanger (B) where it is heated by the extract air from the pool. This pre-warmed air then passes through the heat pump condenser (F) where it is heated by the latent energy removed during the condensation process as well as the energy input to the compressor. The warm dry air is then discharged to the room.
Computational metaphysics Overview Axiomatic_metaphysics > Overview Abstract Objects: An Introduction to Axiomatic Metaphysics (1983) is the title of a publication by Edward Zalta that outlines abstract object theory. AOT is a dual predication approach (also known as "dual copula strategy") to abstract objects influenced by the contributions of Alexius Meinong and his student Ernst Mally. On Zalta's account, there are two modes of predication: some objects (the ordinary concrete ones around us, like tables and chairs) exemplify properties, while others (abstract objects like numbers, and what others would call "nonexistent objects", like the round square and the mountain made entirely of gold) merely encode them. While the objects that exemplify properties are discovered through traditional empirical means, a simple set of axioms allows us to know about objects that encode properties.
Policy iteration Algorithms Markov_Decision_Processes > Algorithms Solutions for MDPs with finite state and action spaces may be found through a variety of methods such as dynamic programming. The algorithms in this section apply to MDPs with finite state and action spaces and explicitly given transition probabilities and reward functions, but the basic concepts may be extended to handle other problem classes, for example using function approximation. The standard family of algorithms to calculate optimal policies for finite state and action MDPs requires storage for two arrays indexed by state: value V {\displaystyle V} , which contains real values, and policy π {\displaystyle \pi } , which contains actions. At the end of the algorithm, π {\displaystyle \pi } will contain the solution and V ( s ) {\displaystyle V(s)} will contain the discounted sum of the rewards to be earned (on average) by following that solution from state s {\displaystyle s} .
Ancient Greek architecture Ionic order Ancient_Greek_architecture > Style > Orders > Ionic order The Ionic order is altogether lighter in appearance than the Doric, with the columns, including base and capital, having a 9:1 ratio with the diameter, while the whole entablature was also much narrower and less heavy than the Doric entablature. There was some variation in the distribution of decoration. Formalised bands of motifs such as alternating forms known as egg-and-dart were a feature of the Ionic entablatures, along with the bands of dentils.
Numerical modeling (geology) Governing equations Numerical_modeling_(geology) > Computation > Governing equations Following are some basic equations that are commonly used to describe physical phenomena, for example, how the matter in a geologic system moves or flows and how heat energy is distributed in a system. These equations are usually the core of the mathematical model.
Physiological psychology Emotion Physiological_psychology > Emotion Another hormone found in the direct response from emotion is adrenocorticotropic hormone (ACTH) secreted in response to fearful stimuli. ACTH is secreted by the posterior pituitary in response to fear and plays a role in the facilitation or inhibition of behaviors and actions to follow. In most cases, a high ACTH secretion will lead to the inhibition of actions that would produce the same fearful response that just occurred.
Secure Enclave Jailbreaking Secure_Enclave > Development > Jailbreaking An additional motivation is that it may enable the installation of pirated apps. On some devices, jailbreaking also makes it possible to install alternative operating systems, such as Android and the Linux kernel. Primarily, users jailbreak their devices because of the limitations of iOS.
Thermoregulation in humans In cold conditions Thermoregulation_in_humans > Control system > In cold conditions This means that less heat is lost to the environment through convection. There are two types of shivering: low-intensity and high-intensity. During low-intensity shivering, animals shiver constantly at a low level for months during cold conditions.
Series-wound motor Disadvantages Series-wound_motor > Working > Disadvantages A negative aspect is the maintenance and short life problems caused by the commutator, as well as electromagnetic interference (EMI) issues due to any sparking. Because of the relatively high maintenance commutator brushes, universal motors are best-suited for devices such as food mixers and power tools which are used only intermittently, and often have high starting-torque demands. Another negative aspect is that these motors may only be used where mostly-clean air is present at all times.
Fractal flame Rendering an image Flame_fractals > Algorithm > Rendering an image To increase the quality of the image, one can use supersampling to decrease the noise. This involves creating a histogram larger than the image so each pixel has multiple data points to pull from. For example, create a histogram with 300×300 cells in order to draw a 100×100 px image; each pixel would use a 3×3 group of histogram buckets to calculate its value.
Parallel processing (psychology) Serial vs parallel processing Parallel_processing_(psychology) > Background > Serial vs parallel processing In contrast to parallel processing, serial processing involves sequential processing of information, without any overlap of processing times. The distinction between these two processing models is most observed during visual stimuli is targeted and processed (also called visual search).
Therapeutic cloning Process Therapeutic_cloning > Process The ovum, now containing the somatic cell's nucleus, is stimulated with a shock and will begin to divide. The egg is now viable and capable of producing an adult organism containing all necessary genetic information from just one parent. Development will ensue normally and after many mitotic divisions, the single cell forms a blastocyst (an early stage embryo with about 100 cells) with an identical genome to the original organism (i.e. a clone). Stem cells can then be obtained by the destruction of this clone embryo for use in therapeutic cloning or in the case of reproductive cloning the clone embryo is implanted into a host mother for further development and brought to term.
Chromium acetate hydroxide Summary Chromium_acetate_hydroxide Chromium acetate hydroxide is the coordination complex with the formula 4. A dark violet solid, it crystallizes as the triacontatetrahydrate (34 molecules of water of crystallization). It is water soluble.
Sensor noise Effects of sensor size Image_noise > In digital cameras > Effects of sensor size For images at lower signal levels (higher ISO settings), where read noise (noise floor) is significant, more pixels within a given sensor area will make the image noisier if the per pixel read noise is the same. For example, the noise level produced by a Four Thirds sensor at ISO 800 is roughly equivalent to that produced by a full frame sensor (with roughly four times the area) at ISO 3200, and that produced by a 1/2.5" compact camera sensor (with roughly 1/16 the area) at ISO 100. All cameras will have roughly the same ISO setting for a given scene at the same shutter speed and the same f-number - resulting in substantially less noise with the full frame camera. Conversely, if all cameras were using lenses with the same aperture diameter, the ISO settings would be different across the cameras, but the noise levels would be roughly equivalent.
Correlative-based fallacies Correlative conjunctions Correlative-based_fallacies > Correlative conjunctions A correlative conjunction is a relationship between two statements where one must be false and the other true. In formal logic this is known as the exclusive or relationship; traditionally, terms between which this relationship exists have been called contradictories.
Automated system Sequential control and logical sequence or system state control Factory_automation > Control > Sequential control and logical sequence or system state control These were more flexible in their response than the rigid single-sequence cam timers. More complicated examples involved maintaining safe sequences for devices such as swing bridge controls, where a lock bolt needed to be disengaged before the bridge could be moved, and the lock bolt could not be released until the safety gates had already been closed. The total number of relays and cam timers can number into the hundreds or even thousands in some factories.
Physics of whistles Reynolds number Physics_of_whistles > Scaling > Reynolds number Re = U L υ {\displaystyle {\text{Re}}={\frac {UL}{\upsilon }}} It is the ratio of the steady inertial forces to the steady viscous forces. The number was named in honor of Osborne Reynolds, an engineer who did pioneering studies on the transition of laminar to turbulent flow in pipes.
Glossary of set theory XYZ Glossary_of_set_theory > XYZ Zermelo's well-ordering theorem states that every set can be well ordered ZF Zermelo−Fraenkel set theory without the axiom of choice ZFA Zermelo−Fraenkel set theory with atoms ZFC Zermelo−Fraenkel set theory with the axiom of choice ZF-P Zermelo−Fraenkel set theory without the axiom of choice or the powerset axiom Zorn 1. Max Zorn 2. Zorn's lemma states that if every chain of a non-empty poset has an upper bound then the poset has a maximal element
Sibyl M. Rock Scholarly publications Sibyl_M._Rock > Scholarly publications "A Computer for Solving Linear Simultaneous Equations". J. Appl. Phys.
Carbometalation Carbopalladation Carbometalation > Carbopalladation Carbopalladations can be a description of the elementary step of a reaction catalyzed by a palladium catalyst (Mizoroki-Heck reaction) and can also refer to a carbometalation reaction with a palladium catalyst (alkene difunctionalization, hydrofunctionalization, or reductive Heck) == References ==
Light-year History Light-year > History The light-year unit appeared a few years after the first successful measurement of the distance to a star other than the Sun, by Friedrich Bessel in 1838. The star was 61 Cygni, and he used a 160-millimetre (6.2 in) heliometre designed by Joseph von Fraunhofer. The largest unit for expressing distances across space at that time was the astronomical unit, equal to the radius of the Earth's orbit at 150 million kilometres (93 million miles).
Epigenetic regulation of neurogenesis Mechanisms Epigenetic_regulation_of_neurogenesis > Mechanisms Three important methods of epigenetic regulation include histone modification, DNA methylation and demethylation, and microRNA (miRNA) expression. Histones keep the DNA of the eukaryotic cell tightly packaged through charge interactions between the positive charge on the histone tail and the negative charge of the DNA, as well as between histone tails of nearby nucleosomes. While there are many different types of histone modifications, in neural epigenetics there are two primary mechanisms which have been explored: histone methylation and histone acetylation. In the former, methyl groups are either added or removed to the histone altering its structure and exposing chromatin and leading to gene activation or deactivation.
Communications server Open Communications_server > Attributes > Open Based on industry-managed open standards Broad, multi-vendor ecosystem Industry certified interoperability Availability of tools that facilitate development and integration of applications at the standardized interfaces Multiple competitive options for standards-based modules
Classical modular curve Galois theory of the modular curve Classical_modular_curve > Galois theory of the modular curve The Galois theory of the modular curve was investigated by Erich Hecke. Considered as a polynomial in x with coefficients in Z, the modular equation Φ0(n) is a polynomial of degree ψ(n) in x, whose roots generate a Galois extension of Q(y). In the case of X0(p) with p prime, where the characteristic of the field is not p, the Galois group of Q(x, y)/Q(y) is PGL(2, p), the projective general linear group of linear fractional transformations of the projective line of the field of p elements, which has p + 1 points, the degree of X0(p). This extension contains an algebraic extension F/Q where if p ∗ = ( − 1 ) ( p − 1 ) / 2 p {\displaystyle p^{*}=(-1)^{(p-1)/2}p} in the notation of Gauss then: F = Q ( p ∗ ) .
3-4-5 triangle Common Pythagorean triples Right_isosceles_triangle > Side-based > Common Pythagorean triples The historian of mathematics Roger L. Cooke observes that "It is hard to imagine anyone being interested in such conditions without knowing the Pythagorean theorem." Against this, Cooke notes that no Egyptian text before 300 BC actually mentions the use of the theorem to find the length of a triangle's sides, and that there are simpler ways to construct a right angle. Cooke concludes that Cantor's conjecture remains uncertain: he guesses that the Ancient Egyptians probably did know the Pythagorean theorem, but that "there is no evidence that they used it to construct right angles".The following are all the Pythagorean triple ratios expressed in lowest form (beyond the five smallest ones in lowest form in the list above) with both non-hypotenuse sides less than 256:
Extradosed bridge History Extradosed_bridge > History The shallow angle of these tendons resulted in them transmitting a large compression force component into the bridge deck structure, allowing them to function in a similar manner to conventional "flexural" bridge prestressing. The extradosed tendons were continuous over the towers and were stressed from the deck level, unlike stay cables, which normally terminate at the top of each pylon. : 5 The first example of a bridge constructed using Mathivat's concepts appears to be the 1993 Ponte dos Socorridos at Camara de Lobos, Portugal, with a main span of 106 m (348 ft).
CD19 Role in development & survival CD19 > Function > Role in development & survival Decisions to live, proliferate, differentiate, or die are continuously being made during B cell development. These decisions are tightly regulated through B cell receptor (BCR) interactions and signaling. The presence of a functional BCR is necessary during antigen-dependent differentiation and for continued survival in the peripheral immune system. Essential to the functionality of a BCR is the presence of CD19.
Looming and similar refraction phenomena Summary Looming_and_similar_refraction_phenomena While mirages are the best known atmospheric refraction phenomena, looming and similar refraction phenomena do not produce mirages. Mirages show an extra image or images of the miraged object, while looming, towering, stooping, and sinking do not. No inverted image is present in those phenomena either.
Lambda lifting Example Lambda_lifting > Example The following OCaml program computes the sum of the integers from 1 to 100: (The let rec declares sum as a function that may call itself.) The function f, which adds sum's argument to the sum of the numbers less than the argument, is a local function. Within the definition of f, n is a free variable. Start by converting the free variable to a parameter: Next, lift f into a global function: The following is the same example, this time written in JavaScript:
Log-structured merge-tree Summary Log-structured_merge-tree A run can be represented on disk as a single file, or alternatively as a collection of files with non-overlapping key ranges. To perform a query on a particular key to get its associated value, one must search in the Level 0 tree and also each run. The Stepped-Merge version of the LSM tree is a variant of the LSM tree that supports multiple levels with multiple tree structures at each level.
Real Mode Summary Real_Mode Real mode, also called real address mode, is an operating mode of all x86-compatible CPUs. The mode gets its name from the fact that addresses in real mode always correspond to real locations in memory. Real mode is characterized by a 20-bit segmented memory address space (giving 1 MB of addressable memory) and unlimited direct software access to all addressable memory, I/O addresses and peripheral hardware. Real mode provides no support for memory protection, multitasking, or code privilege levels. Before the release of the 80286, which introduced protected mode, real mode was the only available mode for x86 CPUs; and for backward compatibility, all x86 CPUs start in real mode when reset, though it is possible to emulate real mode on other systems when starting on other modes.
Nutcracker esophagus Medications Nutcracker_esophagus > Treatment > Medications Medications for nutcracker esophagus includes the use of calcium-channel blockers, which relax the lower esophageal sphincter (LES) and palliate the dysphagia symptoms. Diltiazem, a calcium-channel blocker, has been used in randomized control studies with good effect. Nitrate medications, including isosorbide dinitrate, given before meals, may also help relax the LES and improve symptoms. The inexpensive generic combination of belladonna and phenobarbital (Donnatal and other brands) may be taken three times daily as a tablet to prevent attacks or, for patients with only occasional episodes, as an elixir at the onset of symptoms. Phosphodiesterase inhibitors, such as sildenafil, can be given to reduce symptoms, particularly pain, but small trials have not been able to demonstrate clinical improvement.
Dhrystone Shortcomings Dhrystone > Shortcomings Therefore, an optimizer can replace a string copy with a sequence of word moves without any loops, which will be much faster. This optimization consequently overstates system performance, sometimes by more than 30%.Dhrystone's small code size may fit in the instruction cache of a modern CPU, so that instruction fetch performance is not rigorously tested. Similarly, Dhrystone may also fit completely in the data cache, thus not exercising data cache miss performance. To counter fits-in-the-cache problem, the SPECint benchmark was created in 1988 to include a suite of (initially 8) much larger programs (including a compiler) which could not fit into L1 or L2 caches of that era.
Akt/PKB signaling pathway Cell survival and apoptosis Akt/PKB_signaling_pathway > Downstream effects > Cell survival and apoptosis For example, phosphorylation of BAD, the Bcl-2 family member, on Ser136 causes translocation from the mitochondrial membrane to the cytosol, where it is sequestered by 14-3-3 proteins. Akt phosphorylates Caspase-9 on Ser196, preventing a caspase cascade leading to cell death. Akt also phosphorylates MAP kinase kinase kinases (MAPKKK) upstream of the stress-activated protein kinase (SAPK) pathway. Phosphorylation of apoptosis signal-regulating kinase 1 (ASK1) on Ser83 and mixed lineage kinase 3 (MLK3) on Ser674 inhibits their activity and prevents MAP kinase induced apoptosis.
Differential manifold Partitions of unity Smooth_manifold > Differentiable functions > Partitions of unity Every open covering of a Ck manifold M has a Ck partition of unity. This allows for certain constructions from the topology of Ck functions on Rn to be carried over to the category of differentiable manifolds. In particular, it is possible to discuss integration by choosing a partition of unity subordinate to a particular coordinate atlas, and carrying out the integration in each chart of Rn. Partitions of unity therefore allow for certain other kinds of function spaces to be considered: for instance Lp spaces, Sobolev spaces, and other kinds of spaces that require integration.
Branch Target Injection Mechanism Bounds_Check_Bypass > Mechanism Spectre is a vulnerability that tricks a program into accessing arbitrary locations in the program's memory space. An attacker may read the content of accessed memory, and thus potentially obtain sensitive data. Instead of a single easy-to-fix vulnerability, the Spectre white paper describes a whole class of potential vulnerabilities.
Death associated protein 6 Structure and localization Death_associated_protein_6 > Structure and localization Daxx is uniformly expressed throughout the body, except in the testes and thymus, which have especially high expression of the protein. At the level of the cell, Daxx is found in the cytoplasm, interacting with Fas-receptor or other cytoplasmic molecules, as well as in the nucleus, where it is interacting with some subnuclear structures. Several additional interacting proteins are known, but not always is there an understanding of the specific function and relevance of this interaction.
Coherence theory of justification Summary Epistemic_coherentism It also attempts to offer a solution to the regress argument that plagues correspondence theory. In an epistemological sense, it is a theory about how belief can be proof-theoretically justified. Coherentism is a view about the structure and system of knowledge, or else justified belief.
Protein-RNA interaction Translation Protein-RNA_interaction > Function > Translation Translational regulation provides a rapid mechanism to control gene expression. Rather than controlling gene expression at the transcriptional level, mRNA is already transcribed but the recruitment of ribosomes is controlled. This allows rapid generation of proteins when a signal activates translation. ZBP1 in addition to its role in the localization of B-actin mRNA is also involved in the translational repression of beta-actin mRNA by blocking translation initiation. ZBP1 must be removed from the mRNA to allow the ribosome to properly bind and translation to begin.
Photogravure Technique Photogravure > Technique The sixth stage is to etch the plate in a series of ferric chloride baths, from the densest to slightly more dilute, in steps. The density of these baths is measured in degrees Baumé. The ferric chloride migrates through the gelatin, etching the shadows and blacks under the thinnest areas first.
Fundamental physical constants External articles Dimensionless_physical_constant > External articles Physical Review Letters. 87 (9): 091301. arXiv:astro-ph/0012539. Bibcode:2001PhRvL..87i1301W.
Data Presentation Architecture Terminology Data_presentation > Terminology It is primarily used to look up specific values. In the example above, the table might have categorical column labels representing the name (a qualitative variable) and age (a quantitative variable), with each row of data representing one person (the sampled experimental unit or category subdivision). A graph is primarily used to show relationships among data and portrays values encoded as visual objects (e.g., lines, bars, or points).
Averaged Lagrangian Method Averaged_Lagrangian > Method But the wave phase itself is absent due to the phase averaging. Consequently, through Noether's theorem, there is a conservation law called the conservation of wave action. Originally the averaged Lagrangian method was developed by Whitham for slowly-varying dispersive wave trains. Several extensions have been made, e.g. to interacting wave components, Hamiltonian mechanics, higher-order modulational effects, dissipation effects.
Social defeat Behavioral and physiological effects Social_defeat > In humans > Behavioral and physiological effects In animal studies, animals housed collectively showed reduced symptoms after defeat, in comparison with those housed alone; and animals that live in more stable groups (with stable hierarchies, less intra-group aggression) exhibit reduced effects after a defeat, in comparison with those housed in a more unstable group (de Jong et alli, 2005). In separate studies, defeat behaviors can be modulated by acetylcholine (Smith et al., 2015).In human studies, individuals with greater support seem to be protected against excessive neuroendocrine activation, thereby reducing the adverse effects of stresses in general, and especially stresses of social origin. This apparent confusion, in which social defeat generates behavioral and neuroendocrine effects, both of which depending on social contextual variables, raises the question of how to interpret this data.
Paleofeces Methods of analysis Paleofeces > Methods of analysis At the molecular level, ancient DNA analysis can be used both to identify the species and to provide dietary information. A method using lipid analysis can also be used for species identification, based on the range of fecal sterols and bile acids. These molecules vary between species according to gut biochemistry, and so can distinguish between humans and other animals.
Gift-exchange game Experimental Methods and Results Gift-exchange_game > Experimental Methods and Results Each participant would receive an hourly wage that had been previously advertised to them. The participants in each experiment were divided into two groups, one of which were informed that the actual wage they would be receiving was higher than the wage advertised to them. Each of the two experiments yielded similar results.
Scanning tunnelling microscope Bardeen's formalism Scanning_tunnelling_microscope > Principle of operation > Bardeen's formalism If the two systems are put closer together, but are still separated by a thin vacuum region, the potential acting on an electron in the combined system is UT + US. Here, each of the potentials is spatially limited to its own side of the barrier. Only because the tail of a wave function of one electrode is in the range of the potential of the other, there is a finite probability for any state to evolve over time into the states of the other electrode.
Axiomatic framework Properties Axiomatic_proof > Properties An axiomatic system is said to be consistent if it lacks contradiction. That is, it is impossible to derive both a statement and its negation from the system's axioms. Consistency is a key requirement for most axiomatic systems, as the presence of contradiction would allow any statement to be proven (principle of explosion). In an axiomatic system, an axiom is called independent if it cannot be proven or disproven from other axioms in the system.
Backtracking line search Theoretical guarantee (for gradient descent) Backtracking_line_search > Theoretical guarantee (for gradient descent) In the setting of deep learning, saddle points are also prevalent, see Dauphin et al. (2014). Thus, to apply in deep learning, one needs results for non-convex functions. For convergence to critical points: For example, if the cost function is a real analytic function, then it is shown in Absil, Mahony & Andrews (2005) that convergence is guaranteed.
Computational Fluid Dynamics Vorticity confinement method Computational_Fluid_Dynamics > Methodology > Turbulence models > Vorticity confinement method The vorticity confinement (VC) method is an Eulerian technique used in the simulation of turbulent wakes. It uses a solitary-wave like approach to produce a stable solution with no numerical spreading. VC can capture the small-scale features to within as few as 2 grid cells. Within these features, a nonlinear difference equation is solved as opposed to the finite difference equation. VC is similar to shock capturing methods, where conservation laws are satisfied, so that the essential integral quantities are accurately computed.
BOINC client–server technology Client structure BOINC_client-server_technology > Client structure A drawback to the use of RPC mechanisms is that they are often felt to be security risks because they can be the route by which hackers can intrude upon targeted computers (even if it's configured for connections from the same computer). The GUI is written using the cross-platform WxWidgets toolkit, providing the same user experience on different platforms. Users can connect to BOINC core clients, can instruct those clients to install new science applications, can monitor the progress of ongoing calculations, and can view the BOINC system message logs.
Bernoulli process Summary Bernoulli_measure Every variable Xi in the sequence is associated with a Bernoulli trial or experiment. They all have the same Bernoulli distribution. Much of what can be said about the Bernoulli process can also be generalized to more than two outcomes (such as the process for a six-sided die); this generalization is known as the Bernoulli scheme. The problem of determining the process, given only a limited sample of Bernoulli trials, may be called the problem of checking whether a coin is fair.
Solar boiler PV pump Solar_hot_water_panel > Components > Pump > PV pump One way to power an active system is via a photovoltaic (PV) panel. To ensure proper pump performance and longevity, the (DC) pump and PV panel must be suitably matched. Although a PV-powered pump does not operate at night, the controller must ensure that the pump does not operate when the sun is out but the collector water is not hot enough. PV pumps offer the following advantages: Simpler/cheaper installation and maintenance Excess PV output can be used for household electricity use or put back into the grid Can dehumidify living space Can operate during a power outage Avoids the carbon consumption from using grid-powered pumps
Spectral theory Operator equations Spectral_theory > Operator equations {\displaystyle \int \langle x,(O-\lambda I)y\rangle \langle y,G(\lambda )z\rangle \,dy=\int \langle x,(O-\lambda I)y\rangle \left\langle y,(O-\lambda I)^{-1}z\right\rangle \,dy=\langle x,z\rangle =\delta (x-z).} Using this Green's function property: ∫ ⟨ x , ( O − λ I ) y ⟩ G ( y , z ; λ ) d y = δ ( x − z ) . {\displaystyle \int \langle x,(O-\lambda I)y\rangle G(y,z;\lambda )\,dy=\delta (x-z).}
Tissue healing Systemic factors Wound_healing > Factors affecting wound healing > Systemic factors It also increases the likelihood of certain complications such as wound rupture, wound and flap necrosis, decrease in wound tensile strength and infection. Passive smoking also impairs a proper wound healing process. Age – Increased age (over 60 years) is a risk factor for impaired wound healing.
Relativistic electromagnetism Principle Relativistic_electromagnetism > Principle An observer at rest with respect to a system of static, free charges will see no magnetic field. However, a moving observer looking at the same set of charges does perceive a current, and thus a magnetic field. That is, the magnetic field is simply the electric field, as seen in a moving coordinate system.
Glossary of set theory B Glossary_of_set_theory > B 𝔟 The bounding number, the least size of an unbounded family of sequences of natural numbers B A Boolean algebra BA Baumgartner's axiom, one of three axioms introduced by Baumgartner. BACH Baumgartner's axiom plus the continuum hypothesis. Baire 1. René-Louis Baire 2.
Frobenius-Perron eigenvector Non-negative matrices Perron–Frobenius_theorem > Statement > Non-negative matrices For such a matrix, although the eigenvalues attaining the maximal absolute value might not be unique, their structure is under control: they have the form ω r {\displaystyle \omega r} , where r is a real strictly positive eigenvalue, and ω {\displaystyle \omega } ranges over the complex hth roots of 1 for some positive integer h called the period of the matrix. The eigenvector corresponding to r has strictly positive components (in contrast with the general case of non-negative matrices, where components are only non-negative). Also all such eigenvalues are simple roots of the characteristic polynomial. Further properties are described below.

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