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Chemostat Summary Chemostat A chemostat (from chemical environment is static) is a bioreactor to which fresh medium is continuously added, while culture liquid containing left over nutrients, metabolic end products and microorganisms is continuously removed at the same rate to keep the culture volume constant. By changing the rate with which medium is added to the bioreactor the specific growth rate of the microorganism can be easily controlled within limits.
Electronic drum machine Summary Drum_machine A drum machine is an electronic musical instrument that creates percussion sounds, drum beats, and patterns. Drum machines may imitate drum kits or other percussion instruments, or produce unique sounds, such as synthesized electronic tones. A drum machine often has pre-programmed beats and patterns for popular genres and styles, such as pop music, rock music, and dance music. Most modern drum machines made in the 2010s and 2020s also allow users to program their own rhythms and beats.
Lake aeration Natural aeration Water_aeration > Natural aeration Natural aeration is a type of both sub-surface and surface aeration. It can occur through sub-surface aquatic plants. Through the natural process of photosynthesis, water plants release oxygen into the water providing it with the oxygen necessary for fish to live and aerobic bacteria to break down excess nutrients.Oxygen can be driven into the water when the wind disturbs the surface of the water body and natural aeration can occur through a movement of water caused by an incoming stream, waterfall, or even a strong flood. In large water bodies in temperate climates, autumn turn-over can introduce oxygen rich water into the oxygen poor hypolimnion.
Nervous systems Pathology Nerve_system > Pathology In addition to physical damage, peripheral neuropathy may be caused by many other medical problems, including genetic conditions, metabolic conditions such as diabetes, inflammatory conditions such as Guillain–Barré syndrome, vitamin deficiency, infectious diseases such as leprosy or shingles, or poisoning by toxins such as heavy metals. Many cases have no cause that can be identified, and are referred to as idiopathic. It is also possible for nerves to lose function temporarily, resulting in numbness as stiffness—common causes include mechanical pressure, a drop in temperature, or chemical interactions with local anesthetic drugs such as lidocaine.
Flying Wing Directional stability Flying_Wing > Design > Directional stability With sufficient sweep-back, differential induced drag resulting from the tip vortices and crossflow is sufficient to naturally re-align the aircraft. A complementary approach uses twist or wash-out, reducing the angle of attack towards the wing tips, together with a swept-back wing planform. The Dunne D.5 incorporated this principle and its designer J. W. Dunne published it in 1913.
Christopher Langton Major publications Christopher_Langton > Major publications Complex Systems, 7:89–130, 1993. Melanie Mitchell, James P. Crutchfield and Peter T. Hraber. Dynamics, Computation, and the "Edge of Chaos": A Re-Examination J. P. Crutchfield and K. Young, "Computation at the Onset of Chaos", in Complexity, Entropy and the Physics of Information, W. Zurek, editor, SFI Studies in the Sciences of Complexity, VIII, Addison-Wesley, Reading, Massachusetts (1990) pp. 223–269.
IT baseline protection Baseline security check IT_baseline_protection > Baseline protection process > Baseline security check This is called the (cumulation effect). The applications running on a server determine its need for protection. Several IT applications can run on an IT system.
Dummy variable (statistics) Summary Dummy_variable_(statistics) Dummy variables are commonly used in regression analysis to represent categorical variables that have more than two levels, such as education level or occupation. In this case, multiple dummy variables would be created to represent each level of the variable, and only one dummy variable would take on a value of 1 for each observation. Dummy variables are useful because they allow us to include categorical variables in our analysis, which would otherwise be difficult to include due to their non-numeric nature.
Nuclear fusion–fission hybrid Hybrid concepts Nuclear_fusion–fission_hybrid > Hybrid concepts This leads to an alternate design where the primary purpose of the fusion–fission reactor is to reprocess waste into new fuel. Although far less economical than chemical reprocessing, this process also burns off some of the nastier elements instead of simply physically separating them out. This also has advantages for non-proliferation, as enrichment and reprocessing technologies are also associated with nuclear weapons production. However, the cost of the nuclear fuel produced is very high, and is unlikely to be able to compete with conventional sources.
COPD exacerbation Mechanical ventilation COPD_exacerbation > Treatment > Mechanical ventilation Severe exacerbations can require hospital care where treatments such as oxygen and mechanical ventilation may be required. Mechanical ventilation can be invasive (endotracheal intubation) or non-invasive forms of ventilation such as continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BiPAP).
Cross multiplication Procedure Cross_multiplication > Procedure {\displaystyle ad=cb.} Each step in these procedures is based on a single, fundamental property of equations. Cross-multiplication is a shortcut, an easily understandable procedure that can be taught to students.
Phosphodiester backbone Summary DNA_strand The nitrogenous bases of the two separate polynucleotide strands are bound together, according to base pairing rules (A with T and C with G), with hydrogen bonds to make double-stranded DNA. The complementary nitrogenous bases are divided into two groups, pyrimidines and purines. In DNA, the pyrimidines are thymine and cytosine; the purines are adenine and guanine.
V1 Saliency Hypothesis Neural mechanisms in V1 to generate the saliency map V1_Saliency_Hypothesis > Neural mechanisms in V1 to generate the saliency map This saliency value is thus highest at the location of the orientation singleton, and is represented by the response from neurons preferring and responding to the orientation of this singleton. These saliency values are sent to the superior colliculus, a midbrain area, to execute gaze shifts to the receptive field of the most activated neuron responding to visual input space. Hence, for this input image in the figure above, the orientation singleton, which evokes the highest V1 response to this image, attracts visual attention or gaze.
TCP port Selective acknowledgments TCP_port > Protocol operation > Selective acknowledgments Relying purely on the cumulative acknowledgment scheme employed by the original TCP can lead to inefficiencies when packets are lost. For example, suppose bytes with sequence number 1,000 to 10,999 are sent in 10 different TCP segments of equal size, and the second segment (sequence numbers 2,000 to 2,999) is lost during transmission. In a pure cumulative acknowledgment protocol, the receiver can only send a cumulative ACK value of 2,000 (the sequence number immediately following the last sequence number of the received data) and cannot say that it received bytes 3,000 to 10,999 successfully. Thus the sender may then have to resend all data starting with sequence number 2,000.
Transdifferentiation Pluripotent reprogramming Transdifferentiation > Pluripotent reprogramming Almost all factors that reprogram cells into pluripotency have been discovered and can turn a wide variety of cells back into induced pluripotent stem cells (iPSCs). However, many of the reprogramming factors that can change a cell's lineage have not been discovered and these factors apply only for that specific lineage. The final products of transdifferentiated cells are capable of being used for clinical studies, but iPSCs must be differentiated.
Computational neuroanatomy Composition Neuroanatomy > Composition The somatic nervous system is made up of "afferent" neurons, which bring sensory information from the somatic (body) sense organs to the CNS, and "efferent" neurons, which carry motor instructions out to the voluntary muscles of the body. The autonomic nervous system can work with or without the control of the CNS (that's why it is called 'autonomous'), and also has two subdivisions, called sympathetic and parasympathetic, which are important for transmitting motor orders to the body's basic internal organs, thus controlling functions such as heartbeat, breathing, digestion, and salivation. Autonomic nerves, unlike somatic nerves, contain only efferent fibers. Sensory signals coming from the viscera course into the CNS through the somatic sensory nerves (e.g., visceral pain), or through some particular cranial nerves (e.g., chemosensitive or mechanic signals).
Wildlife forensic science Microscopy Wildlife_forensic_science > Techniques > Microscopy This technique is when genetic microscopes are used to look down to a single cell it is used to look at recombination also look for mutations in genes it has been used to help identify many deleterious alleles in genes.
Deep Learning Partial differential equations Deep_neural_network > Applications > Partial differential equations Physics informed neural networks have been used to solve partial differential equations in both forward and inverse problems in a data driven manner. One example is the reconstructing fluid flow governed by the Navier-Stokes equations. Using physics informed neural networks does not require the often expensive mesh generation that conventional CFD methods relies on.
Routhian mechanics Classical charged particle in a uniform magnetic field Routhian_mechanics > Examples > Velocity-dependent potentials > Classical charged particle in a uniform magnetic field {\displaystyle {\dot {\theta }}={\frac {1}{mr^{2}}}\left(p_{\theta }-{\frac {qBr^{2}}{2}}\right)\,,\quad {\dot {z}}={\frac {p_{z}}{m}}\,.} The angular momentum about the z axis is not pθ, but the quantity mr2dθ/dt, which is not conserved due to the contribution from the magnetic field. The canonical momentum pθ is the conserved quantity.
Coordination polymer Ligand length Coordination_polymers > Ligands > Ligand length A length of the ligand can be an important factor in determining possibility for formation of a polymeric structure versus non-polymeric (mono- or oligomeric) structures.
Continuous map Construction of continuous functions Continuous_(topology) > Real functions > Construction of continuous functions The term removable singularity is used in such cases, when (re)defining values of a function to coincide with the appropriate limits make a function continuous at specific points. A more involved construction of continuous functions is the function composition.
Sodium silicate Water treatment Soluble_glass > Uses > Engineering > Water treatment Sodium silicate is used as an alum coagulant and an iron flocculant in wastewater treatment plants. Sodium silicate binds to colloidal molecules, creating larger aggregates that sink to the bottom of the water column. The microscopic negatively charged particles suspended in water interact with sodium silicate. Their electrical double layer collapses due to the increase of ionic strength caused by the addition of sodium silicate (doubly negatively charged anion accompanied by two sodium cations) and they subsequently aggregate. This process is called coagulation.
Train track map Sketch of the proof Train_track_map > Main result for irreducible automorphisms > Bestvina–Handel theorem for irreducible automorphisms > Sketch of the proof Of these moves the valence-one homotopy always reduced the Perron–Frobenius eigenvalue. Starting with some topological representative f of an irreducible automorphism φ one then algorithmically constructs a sequence of topological representatives f = f1, f2, f3,...of φ where fn is obtained from fn−1 by several moves, specifically chosen. In this sequence, if fn is not a train track map, then the moves producing fn+1 from fn necessarily involve a sequence of folds followed by a valence-one homotopy, so that the Perron–Frobenius eigenvalue of fn+1 is strictly smaller than that of fn. The process is arranged in such a way that Perron–Frobenius eigenvalues of the maps fn take values in a discrete substet of R {\displaystyle \mathbb {R} } . This guarantees that the process terminates in a finite number of steps and the last term fN of the sequence is a train track representative of φ.
Glycogen storage disease type V Structure Glycogen_storage_disease_type_V > Genetics > Myophosphorylase > Structure Ser-14 is modified by phosphorylase kinase during activation of the enzyme. Lys-680 is involved in binding the pyridoxal phosphate, which is the active form of vitamin B6, a cofactor required by myophosphorylase. By similarity, other sites have been estimated: Tyr-76 binds AMP, Cys-109 and Cys-143 are involved in subunit association, and Tyr-156 may be involved in allosteric control.
Nonlinear control theory Nonlinear feedback analysis – The Lur'e problem Nonlinear_Control > Nonlinear feedback analysis – The Lur'e problem An early nonlinear feedback system analysis problem was formulated by A. I. Lur'e. Control systems described by the Lur'e problem have a forward path that is linear and time-invariant, and a feedback path that contains a memory-less, possibly time-varying, static nonlinearity. The linear part can be characterized by four matrices (A,B,C,D), while the nonlinear part is Φ(y) with Φ ( y ) y ∈ , a < b ∀ y {\displaystyle {\frac {\Phi (y)}{y}}\in ,\quad a
Lachancea thermotolerans Uses Lachancea_thermotolerans > Uses It has been observed that this kind of yeast ferments at low temperatures (17 °C) as well as at high temperatures (27 °C) and with SO2 doses of 25 mg/L and 75 mg/L with an ethanol yield between 7-11% vol. Sequential inoculations (binary) and sequential co-inoculations (ternary) with different non-Saccharomyces, including L. thermotolerans, have also been studied, resulting in very significant synergies and inhibitions in lactic acid production. == References ==
Flight simulation video game Flight and space flight simulators Amateur_flight_simulator > Home software > Flight and space flight simulators The series' latest installment, simply called Microsoft Flight Simulator, was released on August 18, 2020. X-Plane, a realistic simulator developed by Laminar Research since 1993 which also includes a Space Shuttle and Mars flight simulators Kerbal Space Program, spacecraft and aircraft construction and flight simulator; initially space-focused, but the addition of air-breathing engines and lift surfaces made atmospheric flight practical. The simulation is of a fictitious world and not based on the real world or solar system, and the idea is more to preserve some of the concepts of space flight while allowing entertaining gameplay
Protein molecule Nutrition Cellular_protein > Nutrition In animals, amino acids are obtained through the consumption of foods containing protein. Ingested proteins are then broken down into amino acids through digestion, which typically involves denaturation of the protein through exposure to acid and hydrolysis by enzymes called proteases. Some ingested amino acids are used for protein biosynthesis, while others are converted to glucose through gluconeogenesis, or fed into the citric acid cycle.
Optimal design of experiments Summary Optimal_design In the design of experiments, optimal designs (or optimum designs) are a class of experimental designs that are optimal with respect to some statistical criterion. The creation of this field of statistics has been credited to Danish statistician Kirstine Smith.In the design of experiments for estimating statistical models, optimal designs allow parameters to be estimated without bias and with minimum variance. A non-optimal design requires a greater number of experimental runs to estimate the parameters with the same precision as an optimal design.
Materiality (architecture) Summary Materiality_(architecture) Materiality in architecture is a concept or the applied use of various materials or substances in the medium of building. This concept was previously regarded as a secondary consideration in architecture but recently emerged as an important element due to advances in digital fabrication and digital science.The concept plays an important role in architectural practice, which is actualized through the body and senses of an architect interacting with his physical work environment. It defines critical aspects concerning the governance and engagement of an architectural system.
Pure substance Chemical elements Chemical_substance > Chemical elements An element is a chemical substance made up of a particular kind of atom and hence cannot be broken down or transformed by a chemical reaction into a different element, though it can be transmuted into another element through a nuclear reaction. This is because all of the atoms in a sample of an element have the same number of protons, though they may be different isotopes, with differing numbers of neutrons. As of 2019, there are 118 known elements, about 80 of which are stable – that is, they do not change by radioactive decay into other elements. Some elements can occur as more than a single chemical substance (allotropes).
Power electronic AC/AC converters Industrial_electronics > AC/AC converters Two sub-categories exist from the hybrid converters, named hybrid direct matrix converter (HDMC) and hybrid indirect matrix converter (HIMC). HDMC convert the voltage and current in one stage, while the HIMC utilizes separate stages, like the AC/DC/AC converter, but without the use of an intermediate storage element.Applications: Below is a list of common applications that each converter is used in. AC voltage controller: Lighting control; domestic and industrial heating; speed control of fan, pump or hoist drives, soft starting of induction motors, static AC switches (temperature control, transformer tap changing, etc.) Cycloconverter: High-power low-speed reversible AC motor drives; constant frequency power supply with variable input frequency; controllable VAR generators for power factor correction; AC system interties linking two independent power systems.
Point-of-care ultrasound Monitoring therapy Point-of-care_ultrasound > Scope > Monitoring therapy Emergency ultrasound can not only diagnose, but also monitor a person's response to therapeutic interventions. Ultrasound can be utilized to assess a person's intravascular volume status and response to intravenous fluid therapy by measuring the size and respiratory change in the diameter of the IVC, including the assessment of central venous collapsibility as a more standardized measure of intravascular volume status. More recent evidence suggests that ultrasound assessment of more "peripheral" veins (e.g., subclavian, femoral, internal jugular) may also be helpful in estimating intravascular volume status in the absence of IVC visualization. Ultrasound of the lungs may demonstrate resolution of pulmonary edema from congestive heart failure.
Unifying Systems in Catalysis Consortium Unifying_Systems_in_Catalysis > Consortium Technische Universität Berlin Humboldt Universität zu Berlin Freie Universität Berlin Universität Potsdam Charité - Universitätsmedizin Fritz-Haber-Institut der Max-Planck-Gesellschaft Max-Planck-Institut for Colloids and Interfaces Helmholtz-Zentrum Berlin Leibniz-Forschungsinstitut für Molekulare PharmakologieSpokespersons: Holger Dobbek (HU Berlin), Matthias Driess (TU Berlin), Arne Thomas (TU Berlin)
Linear endomorphism Summary Linear_isomorphism In mathematics, and more specifically in linear algebra, a linear map (also called a linear mapping, linear transformation, vector space homomorphism, or in some contexts linear function) is a mapping V → W {\displaystyle V\to W} between two vector spaces that preserves the operations of vector addition and scalar multiplication. The same names and the same definition are also used for the more general case of modules over a ring; see Module homomorphism. If a linear map is a bijection then it is called a linear isomorphism.
Virtual work Summary Principle_of_Virtual_Work In mechanics, virtual work arises in the application of the principle of least action to the study of forces and movement of a mechanical system. The work of a force acting on a particle as it moves along a displacement is different for different displacements. Among all the possible displacements that a particle may follow, called virtual displacements, one will minimize the action.
Bruno Latour Laboratory Life Bruno_Latour > Main works > Laboratory Life In the laboratory, Latour and Woolgar observed that a typical experiment produces only inconclusive data that is attributed to failure of the apparatus or experimental method, and that a large part of scientific training involves learning how to make the subjective decision of what data to keep and what data to throw out. Latour and Woolgar argued that, for untrained observers, the entire process resembles not an unbiased search for truth and accuracy but a mechanism for ignoring data that contradicts scientific orthodoxy. Latour and Woolgar produced a highly heterodox and controversial picture of the sciences.
Neuroscience of sleep Sleep regulation Neuroscience_of_sleep > Sleep regulation Sleep regulation refers to the control of when an organism transitions between sleep and wakefulness. The key questions here are to identify which parts of the brain are involved in sleep onset and what their mechanisms of action are. In humans and most animals sleep and wakefulness seems to follow an electronic flip-flop model i.e. both states are stable, but the intermediate states are not. Of course, unlike in the flip-flop, in the case of sleep, there seems to be a timer ticking away from the minute of waking so that after a certain period one must sleep, and in such a case even waking becomes an unstable state. The reverse may also be true to a lesser extent.
Methods of computing square roots Decimal (base 10) Heron's_method > Digit-by-digit calculation > Decimal (base 10) Place the digit x {\displaystyle x} as the next digit of the root, i.e., above the two digits of the square you just brought down. Thus the next p will be the old p times 10 plus x. Subtract y from c to form a new remainder. If the remainder is zero and there are no more digits to bring down, then the algorithm has terminated. Otherwise go back to step 1 for another iteration.
Bacterial phylodynamics Summary Bacterial_phylodynamics Bacterial phylodynamics is the study of immunology, epidemiology, and phylogenetics of bacterial pathogens to better understand the evolutionary role of these pathogens. Phylodynamic analysis includes analyzing genetic diversity, natural selection, and population dynamics of infectious disease pathogen phylogenies during pandemics and studying intra-host evolution of viruses. Phylodynamics combines the study of phylogenetic analysis, ecological, and evolutionary processes to better understand of the mechanisms that drive spatiotemporal incidence and phylogenetic patterns of bacterial pathogens.
Plot sampling Summary Plot_sampling In ecology, plot sampling is a method of abundance estimation in which plots are selected from within a survey region and sampled; population estimates can then be made using the Horvitz–Thompson estimator. Generally plot sampling is a useful method if it can be assumed that each survey will identify all of the animals in the sampled area, and that the animals will be distributed uniformly and independently. If the entire survey region is covered in this manner, rather than a subset of plots that are then used for extrapolation, this is considered a census rather than a plot sampling approach.
Edward Thorndike Adult learning Edward_Thorndike > Adult learning The more similar the situations are, the greater the amount of information that will transfer. Similarly, if the situations have nothing in common, information learned in one situation will not be of any value in the other situation. Associative shifting- it is possible to shift any response from occurring with one stimulus to occurring with another stimulus.
Convexity of radius History Convexity_of_radius > History The word radius is Latin for "ray". In the context of the radius bone, a ray can be thought of rotating around an axis line extending diagonally from center of capitulum to the center of distal ulna. While the ulna is the major contributor to the elbow joint, the radius primarily contributes to the wrist joint.The radius is named so because the radius (bone) acts like the radius (of a circle). It rotates around the ulna and the far end (where it joins to the bones of the hand), known as the styloid process of the radius, is the distance from the ulna (center of the circle) to the edge of the radius (the circle). The ulna acts as the center point to the circle because when the arm is rotated the ulna does not move.
Green algal derived chloroplast Specialized chloroplasts in C4 plants Chloroplast > Structure > Specialized chloroplasts in C4 plants To fix carbon dioxide into sugar molecules in the process of photosynthesis, chloroplasts use an enzyme called RuBisCO. RuBisCO has trouble distinguishing between carbon dioxide and oxygen, so at high oxygen concentrations, RuBisCO starts accidentally adding oxygen to sugar precursors. This has the result of ATP energy being wasted and CO2 being released, all with no sugar being produced. This is a big problem, since O2 is produced by the initial light reactions of photosynthesis, causing issues down the line in the Calvin cycle which uses RuBisCO.C4 plants evolved a way to solve this—by spatially separating the light reactions and the Calvin cycle.
Intelligent tutoring system Early electronic systems Intelligent_tutoring_systems > History > Early electronic systems The Turing test has been used in its essence for more than two decades as a model for current ITS development. The main ideal for ITS systems is to effectively communicate. As early as the 1950s programs were emerging displaying intelligent features.
Cardan shaft Advantages Propeller_shaft > Drive shafts in bicycles > Advantages Drive system is less likely to become jammed. The rider cannot become dirtied from chain grease or injured by "chain bite" when clothing or a body part catches between an unguarded chain and a sprocket. Lower maintenance than a chain system when the drive shaft is enclosed in a tube. More consistent performance. Dynamic Bicycles claims that a drive shaft bicycle can deliver 94% efficiency, whereas a chain-driven bike can deliver anywhere from 75 to 97% efficiency based on condition.
Schiff base Coordination chemistry Schiff_bases > Coordination chemistry The term Schiff base is normally applied to these compounds when they are being used as ligands to form coordination complexes with metal ions. One example is Jacobsen's catalyst. The imine nitrogen is basic and exhibits pi-acceptor properties.
Pp-wave metrics Relation to other classes of exact solutions Pp-wave_metrics > Relation to other classes of exact solutions (See also the article on plane wave spacetimes for a discussion of physically important special cases of plane waves.) J. D. Steele has introduced the notion of generalised pp-wave spacetimes. These are nonflat Lorentzian spacetimes which admit a self-dual covariantly constant null bivector field.
Quaternions and spatial rotation Using quaternions as rotations Quaternions_and_spatial_rotation > Using quaternions as rotations In 3-dimensional space, according to Euler's rotation theorem, any rotation or sequence of rotations of a rigid body or coordinate system about a fixed point is equivalent to a single rotation by a given angle θ {\displaystyle \theta } about a fixed axis (called the Euler axis) that runs through the fixed point. The Euler axis is typically represented by a unit vector u → {\displaystyle {\vec {u}}} ( e ^ {\displaystyle {\hat {e}}} in the picture). Therefore, any rotation in three dimensions can be represented as via a vector u → {\displaystyle {\vec {u}}} and an angle θ {\displaystyle \theta } . Quaternions give a simple way to encode this axis–angle representation using four real numbers, and can be used to apply (calculate) the corresponding rotation to a position vector (x,y,z), representing a point relative to the origin in R3.
Janna Levin Biography Janna_Levin > Biography In addition she is the director of sciences at Pioneer Works.Levin is the author of the popular science book How the Universe Got Its Spots: Diary of a Finite Time in a Finite Space. In 2006, she published A Madman Dreams of Turing Machines, a novel of ideas recounting the lives and deaths of Kurt Gödel and Alan Turing.Levin has written a series of essays to accompany exhibitions at several galleries in England, including the Ruskin School of Drawing and Fine Art and the Hayward Gallery. Levin was featured on Talk of the Nation on July 12, 2002.
Molecular Nanotechnology Redefining of the word "nanotechnology" Molecular_Nanotechnology > Technical issues and criticism > Redefining of the word "nanotechnology" For the future, some means have to be found for MNT design evolution at the nanoscale which mimics the process of biological evolution at the molecular scale. Biological evolution proceeds by random variation in ensemble averages of organisms combined with culling of the less-successful variants and reproduction of the more-successful variants, and macroscale engineering design also proceeds by a process of design evolution from simplicity to complexity as set forth somewhat satirically by John Gall: "A complex system that works is invariably found to have evolved from a simple system that worked. . .
Text Executive Programming Language TEX Variables Text_Executive_Programming_Language > TEX Variables All variables were stored as strings and converted to integer numeric values when required. Floating point variables, arrays, or other datatypes common in current scripting languages did not exist in a TEX environment. All variables were stored in a single global variable pool which users had to manage in order to avoid variable naming conflicts. There were no variable scoping capabilities in TEX.
Shock and Vibration Information Analysis Center Summary Shock_and_Vibration_Information_Analysis_Center This broad field includes such technical areas as the testing, analysis and design of structural or mechanical systems subjected to dynamic conditions and loading such as vibration, blast, impact, and shock for various agencies in the U. S. Government including NASA, the Department of Energy (DOE), and the Department of Defense (DOD). The organization sponsored the professional journal Shock and Vibration Journal and currently sponsors and publishes the professional journal Journal of Critical Technology in Shock and Vibration. SAVIAC also sponsored and published a series of monograms addressing different aspects of shock and vibration.
Complex geometry Idea Complex_geometry > Idea This equivalence indicates that complex geometry is in some sense closer to algebraic geometry than to differential geometry. Another example of this which links back to the nature of the complex plane is that, in complex analysis of a single variable, singularities of meromorphic functions are readily describable. In contrast, the possible singular behaviour of a continuous real-valued function is much more difficult to characterise.
Minoru Ozima Research Minoru_Ozima > Research Noble gases are not rare elements in the Sun or the Solar System generally but are extremely depleted on the planet Earth, with lighter elements being the most depleted. In the 1960s, it was generally assumed that the noble gases were unimportant in the formation and evolution of the Earth. In the 1970s, Ozima presented a novel theory, based on measurements of isotopes, that explained the formation of the Earth's atmosphere as the result of a catastrophic degassing event on the Earth within ~100 million years of the Earth’s formation. Through this and subsequent work, Ozima has developed the only model of planetary formation to explain the fractionation patterns of the noble gases. His work in noble gas geochemistry has enabled researchers to understand processes of planetary formation of the early Solar System.
Satellite watching Spotting satellites Satellite_watching > Spotting satellites They are lit solely by the reflection of sunlight from solar panels or other surfaces. A satellite's brightness sometimes changes as it moves across the sky. Occasionally a satellite will 'flare' as it changes orientation relative to the viewer, suddenly increasing in reflectivity.
Gauss's law for magnetism Vector potential Gauss'_law_for_magnetism > Vector potential Due to the Helmholtz decomposition theorem, Gauss's law for magnetism is equivalent to the following statement: The vector field A is called the magnetic vector potential. Note that there is more than one possible A which satisfies this equation for a given B field. In fact, there are infinitely many: any field of the form ∇ϕ can be added onto A to get an alternative choice for A, by the identity (see Vector calculus identities): since the curl of a gradient is the zero vector field: This arbitrariness in A is called gauge freedom.
AMP-activated protein kinase Controversy over role in adaption to exercise/training AMP-activated_protein_kinase > Controversy over role in adaption to exercise/training This is due in part to the marked increases in the mitochondrial biogenesis, upregulation of GLUT-4, UCP-3, Hexokinase II along with other metabolic and mitochondrial enzymes despite decreases in AMPK activity with training. Questions also arise because skeletal muscle cells which express these decreases in AMPK activity in response to endurance training also seem to be maintaining an oxidative dependent approach to metabolism, which is likewise thought to be regulated to some extent by AMPK activity.If the AMPK response to exercise is responsible in part for biochemical adaptations to training, how then can these adaptations to training be maintained if the AMPK response to exercise is being attenuated with training? It is hypothesized that these adaptive roles to training are maintained by AMPK activity and that the increases in AMPK activity in response to exercise in trained skeletal muscle have not yet been observed due to biochemical adaptations that the training itself stimulated in the muscle tissue to reduce the metabolic need for AMPK activation. In other words, due to previous adaptations to training, AMPK will not be activated, and further adaptation will not occur, until the intracellular ATP levels become depleted from an even higher intensity energy challenge than prior to those previous adaptations.
Septic systems Description Septic_tanks > Description A septic tank consists of one or more concrete or plastic tanks of between 4,500 and 7,500 litres (1,000 and 2,000 gallons); one end is connected to an inlet wastewater pipe and the other to a septic drain field. Generally these pipe connections are made with a T pipe, allowing liquid to enter and exit without disturbing any crust on the surface. Today, the design of the tank usually incorporates two chambers, each equipped with an access opening and cover, and separated by a dividing wall with openings located about midway between the floor and roof of the tank. Wastewater enters the first chamber of the tank, allowing solids to settle and scum to float.
Observational learning Effect on behavior Observational_learning > Effect on behavior According to Bandura's social cognitive learning theory, observational learning can affect behavior in many ways, with both positive and negative consequences. It can teach completely new behaviors, for one. It can also increase or decrease the frequency of behaviors that have previously been learned.
Exponential response formula Linear time-invariant operator Exponential_response_formula > Context and method > Linear time-invariant operator The differential equations are important in simulating natural phenomena. In particular, there are numerous phenomena described as high order linear differential equations, for example the spring vibration, LRC circuit, beam deflection, signal processing, control theory and LTI systems with feedback loops. Mathematically, the system is time-invariant if whenever the input f ( t ) {\displaystyle f(t)} has response x ( t ) {\displaystyle x(t)} then for any constant "a", the input f ( t − a ) {\displaystyle f(t-a)} has response x ( t − a ) {\displaystyle x(t-a)} . Physically, time invariance means system’s response does not depend on what time the input begins.
Seismic Oceanography Analysis Seismic_Oceanography > Method > Analysis The key advantage of seismic oceanography is that it provides high-resolution (up to 10 m) images of oceanic structure, that can be combined with quantitative information about the ocean. The imagery can be used to identify the length, width, and height of oceanic structures across a range of scales. If the seismic data is also 3D, then the evolution of the structures over time can be analyzed too.
Geophysics Gravity Geophysics > Physical phenomena > Gravity The surface gravitational field provides information on the dynamics of tectonic plates. The geopotential surface called the geoid is one definition of the shape of the Earth. The geoid would be the global mean sea level if the oceans were in equilibrium and could be extended through the continents (such as with very narrow canals).
Discrete-time Markov chain Communicating classes and properties Discrete-time_Markov_chain > Communicating classes and properties A state i is said to be essential or final if for all j such that i → j it is also true that j → i. A state i is inessential if it is not essential. A state is final if and only if its communicating class is closed. A Markov chain is said to be irreducible if its state space is a single communicating class; in other words, if it is possible to get to any state from any state.
Extended discrete element method Methodology Extended_discrete_element_method > Methodology It encompasses a larger degree of flexibility because it can use many solvers. Furthermore, it allows a more modular software development.
Hidden oscillation Selected lectures Hidden_oscillation > Selected lectures N.Kuznetsov, Invited lecture The theory of hidden oscillations and stability of dynamical systems, Int. Workshop on Applied Mathematics, Czech Republic, 2021 Afraimovich Award's plenary lecture: N. Kuznetsov The theory of hidden oscillations and stability of dynamical systems. Int. Conference on Nonlinear Dynamics and Complexity, 2021
Mode dial Automatic scene modes Mode_dial > Modes > Automatic scene modes In automatic modes the camera determines all aspects of exposure, choosing exposure parameters according to the application within the constraints of correct exposure, including exposure, aperture, focussing, light metering, white balance, and equivalent sensitivity. For example in portrait mode the camera would use a wider aperture to render the background out of focus, and would seek out and focus on a human face rather than other image content. In the same light conditions a smaller aperture would be used for a landscape, and recognition of faces would not be enabled for focussing. Some cameras have tens of modes, showing the majority only in the menu rather than on the dial.
Biology of depression Catecholamines Biology_of_depression > Monoamines > Monoamine hypothesis of depression > Catecholamines A number of lines of evidence indicative of decreased adrenergic activity in depression have been reported. Findings include the decreased activity of tyrosine hydroxylase, decreased size of the locus coeruleus, increased alpha 2 adrenergic receptor density, and decreased alpha 1 adrenergic receptor density. Furthermore, norepinephrine transporter knockout in mice models increases their tolerance to stress, implicating norepinephrine in depression.One method used to study the role of monoamines is monoamine depletion. Depletion of tryptophan (the precursor of serotonin), tyrosine and phenylalanine (precursors to dopamine) does result in decreased mood in those with a predisposition to depression, but not in persons lacking the predisposition. On the other hand, inhibition of dopamine and norepinephrine synthesis with alpha-methyl-para-tyrosine does not consistently result in decreased mood.
Function (mathematics) In computer science Function_(mathematics) > In computer science In computer programming, a function is, in general, a piece of a computer program, which implements the abstract concept of function. That is, it is a program unit that produces an output for each input. However, in many programming languages every subroutine is called a function, even when there is no output, and when the functionality consists simply of modifying some data in the computer memory. Functional programming is the programming paradigm consisting of building programs by using only subroutines that behave like mathematical functions.
APC gene Summary APC_gene The protein made by the APC gene plays a critical role in several cellular processes that determine whether a cell may develop into a tumor. The APC protein helps control how often a cell divides, how it attaches to other cells within a tissue, how the cell polarizes and the morphogenesis of the 3D structures, or whether a cell moves within or away from tissue. This protein also helps ensure that the chromosome number in cells produced through cell division is correct.
Natural science Newton and the scientific revolution (1600–1800) Natural_science > History > Newton and the scientific revolution (1600–1800) Newton, an English mathematician, and physicist was the seminal figure in the scientific revolution. Drawing on advances made in astronomy by Copernicus, Brahe, and Kepler, Newton derived the universal law of gravitation and laws of motion. These laws applied both on earth and in outer space, uniting two spheres of the physical world previously thought to function independently of each other, according to separate physical rules.
Envelope detector Demodulation of signals Envelope_detector > Demodulation of signals An envelope detector can be used to demodulate a previously modulated signal by removing all high frequency components of the signal. The capacitor and resistor form a low-pass filter to filter out the carrier frequency. Such a device is often used to demodulate AM radio signals because the envelope of the modulated signal is equivalent to the baseband signal.
Matrix analytic method Method description Matrix_analytic_method > Method description Matching the structure of P, π is partitioned to π1, π2, π3, …. To compute these probabilities the column stochastic matrix G is computed such that G = ∑ i = 0 ∞ G i A i . {\displaystyle G=\sum _{i=0}^{\infty }G^{i}A_{i}.}
Failure Mode, Effects, and Criticality Analysis Methodology Failure_Mode,_Effects,_and_Criticality_Analysis > Methodology A piece-part FMECA requires far more effort, but provides the benefit of better estimates of probabilities of occurrence. However, Functional FMEAs can be performed much earlier, may help to better structure the complete risk assessment and provide other type of insight in mitigation options. The analyses are complementary. The criticality analysis may be quantitative or qualitative, depending on the availability of supporting part failure data.
Array programming BASIC Array_programming > Languages > Array languages > BASIC Dartmouth BASIC had MAT statements for matrix and array manipulation in its third edition (1966).
Work visa Summary Work_visa A work permit or work visa is the permission to take a job within a foreign country. The foreign country where someone seeks to obtain a work permit for is also known as the "country of work", as opposed to the "country of origin" where someone holds citizenship or nationality.
Through arch bridge Summary Steel_arch_bridge A through arch bridge, also known as a through-type arch bridge, is a bridge that is made from materials such as steel or reinforced concrete, in which the base of an arch structure is below the deck but the top rises above it. It can either be lower bearing or mid-bearing. Thus, the deck is within the arch, and cables or beams that are in tension suspend the central part of the deck from the arch.
Autonomous flight Spot Automated_driving_system > Assistance robots > Spot This robot is a four-legged nimble robot that was created to be able to navigate through many different terrain outdoors and indoors. It can walk on its own without colliding into anything. It utilizes many different sensors, including 360 vision cameras and gyroscopes. It is able to keep its balance even when pushed over. This vehicle, while it is not intended to be ridden, can carry heavy loads for construction workers or military personnel through rough terrain.
Electron tunneling The Schrödinger equation Tunneling_time > Mathematical discussion > The Schrödinger equation The mathematics of dealing with the situation where M(x) varies with x is difficult, except in special cases that usually do not correspond to physical reality. A full mathematical treatment appears in the 1965 monograph by Fröman and Fröman. Their ideas have not been incorporated into physics textbooks, but their corrections have little quantitative effect.
Rocket propulsion Purpose and function Spacecraft_Propulsion > Purpose and function In an ion thruster, electricity is used to accelerate ions out the back. Here some other source must provide the electrical energy (perhaps a solar panel or a nuclear reactor), whereas the ions provide the reaction mass.When discussing the efficiency of a propulsion system, designers often focus on effective use of the reaction mass, which must be carried along with the rocket and is irretrievably consumed when used. One measure of the amount of impulse that can be obtained from a fixed amount of reaction mass is the specific impulse, the impulse per unit weight-on-Earth (typically designated by I sp {\displaystyle I_{\text{sp}}} ), with units of seconds.
Jetboat Summary Jetboat The well known Hamilton turn or "jet spin" is a high-speed manoeuvre where the boat's engine throttle is cut, the steering is turned sharply and the throttle opened again, causing the boat to spin quickly around with a large spray of water. There is no engineering limit to the size of jetboats, though whether they are useful depends on the type of application. Classic prop-drives are generally more efficient and economical at low speeds, up to about 20 knots (37 km/h; 23 mph), but as boat speed increases, the extra hull resistance generated by struts, rudders, shafts and so on means waterjets are more efficient up to 50 knots (93 km/h; 58 mph).
Knowledge graph Summary Knowledge_graph In knowledge representation and reasoning, knowledge graph is a knowledge base that uses a graph-structured data model or topology to integrate data. Knowledge graphs are often used to store interlinked descriptions of entities – objects, events, situations or abstract concepts – while also encoding the semantics underlying the used terminology.Since the development of the Semantic Web, knowledge graphs are often associated with linked open data projects, focusing on the connections between concepts and entities. They are also prominently associated with and used by search engines such as Google, Bing, Yext and Yahoo; knowledge-engines and question-answering services such as WolframAlpha, Apple's Siri, and Amazon Alexa; and social networks such as LinkedIn and Facebook.
Kaufmann–Bucherer–Neumann experiments Secondary sources Kaufmann–Bucherer–Neumann_experiments > References > Secondary sources 2: 137–150. Janssen, Michel; Mecklenburg, Matthew (2007), "From classical to relativistic mechanics: Electromagnetic models of the electron", in V. F. Hendricks; et al. (eds.
Fluid loss Dependence on lost solutes Fluid_loss > By body fluid compartment > Dependence on lost solutes Na+ loss approximately correlates with fluid loss from ECF, since Na+ has a much higher concentration in ECF than ICF. In contrast, K+ has a much higher concentration in ICF than ECF, and therefore its loss rather correlates with fluid loss from ICF, since K+ loss from ECF causes the K+ in ICF to diffuse out of the cells, dragging water with it by osmosis.
Riffle shuffle permutation Combinatorial enumeration Riffle_shuffle_permutation > Combinatorial enumeration Since a ( p , q ) {\displaystyle (p,q)} -shuffle is completely determined by how its first p {\displaystyle p} elements are mapped, the number of ( p , q ) {\displaystyle (p,q)} -shuffles is However, the number of distinct riffles is not quite the sum of this formula over all choices of p {\displaystyle p} and q {\displaystyle q} adding to n {\displaystyle n} (which would be 2 n {\displaystyle 2^{n}} ), because the identity permutation can be represented in multiple ways as a ( p , q ) {\displaystyle (p,q)} -shuffle for different values of p {\displaystyle p} and q {\displaystyle q} . Instead, the number of distinct riffle shuffle permutations of a deck of n {\displaystyle n} cards, for n = 1 , 2 , 3 , … {\displaystyle n=1,2,3,\dots } , is More generally, the formula for this number is 2 n − n {\displaystyle 2^{n}-n} ; for instance, there are 4503599627370444 riffle shuffle permutations of a 52-card deck. The number of permutations that are both a riffle shuffle permutation and the inverse permutation of a riffle shuffle is For n = 1 , 2 , 3 , … {\displaystyle n=1,2,3,\dots } , this is and for n = 52 {\displaystyle n=52} there are exactly 23427 invertible shuffles.
Ecological selection Vs. sexual selection Ecological_selection > Vs. sexual selection A few such catastrophic events where ecological selection predominates can lead to a population with specific advantages, e.g. in colonization when invading populations from more crowded disease-prone conditions arrive with antibodies to diseases, and the diseases themselves, which proceed to wipe out natives, clearing the way for the colonists. In humans, the intervention of artificial devices such as ships or blankets may be enough to make some consider this an example of artificial selection. However it is clearly observed in other species, it seems unreasonable to differentiate colonization by ship from colonization by walking, and even the word "colony" is not specific to humans but refers generically to an intrusion of one species on an ecology to which it has not wholly adapted.
Incompressibility method Turing-machine time complexity Incompressibility_method > Applications > Turing-machine time complexity For convenience, consider words with the middle third of the word consisting of 0s. The accepting Turing machine ends with an accept state on the left (the beginning of the tape). A Turing-machine computation of a given word gives for each location (the boundary between adjacent cells) a sequence of crossings from left to right and right to left, each crossing in a particular state of the finite control.
Kunerth's algorithm Summary Kunerth's_algorithm a l p h a 2 ∗ x 2 + ( 2 ∗ a l p h a ∗ b e t a − N ) x + ( b e t a 2 − ( y 2 mod N ) ) {\displaystyle alpha^{2}*x^{2}+(2*alpha*beta-N)x+(beta^{2}-(y^{2}{\bmod {N}}))} obtaining an answer like (-37 + 9 x) (1 + 25 x)6) Obtain the modular square root by the equation. Remember to set X so that the term above is zero. Thus X would be 37/9 or -1/25. y ≡ a l p h a ∗ X + b e t a mod N {\displaystyle y\equiv alpha*X+beta{\bmod {N}}} The hard step is the solving of the quadratic equation, but if this can be done then the algorithm quickly finds the modular square root without much computation.
Shvo catalyst Summary Shvo_catalyst The Shvo catalyst is an organoruthenium compound that catalyzes the hydrogenation of polar functional groups including aldehydes, ketones and imines. The compound is of academic interest as an early example of a catalyst for transfer hydrogenation that operates by an "outer sphere mechanism". Related derivatives are known where p-tolyl replaces some of the phenyl groups. Shvo's catalyst represents a subset of homogeneous hydrogenation catalysts that involves both metal and ligand in its mechanism.
Force control Application Force_control > Application In force control, a basic distinction can be made between applications with pronounced contact and applications with potential contact. We speak of pronounced contact when the contact of the machine with the environment or the workpiece is a central component of the task and is explicitly controlled. This includes, above all, tasks of mechanical deformation and surface machining. In tasks with potential contact, the process function variable is the positioning of the machine or its parts.
Periodic graph (crystallography) Basic formulation Periodic_Graphs_(Crystallography) > Basic formulation A Euclidean graph in three-dimensional space is a pair (V, E), where V is a set of vertices (sometimes called points or nodes) and E is a set of edges (sometimes called bonds or spacers) where each edge joins two vertices. There is a tendency in the polyhedral and chemical literature to refer to geometric graphs as nets (contrast with polyhedral nets), and the nomenclature in the chemical literature differs from that of graph theory.
McShane integral Example 1 McShane_integral > Examples > Example 1 Since each one of those intervals do not overlap the interior of all the remaining, we obtain | S ( P , f ) − ( b − a ) | < 2 δ ( a ) + 2 δ ( b ) = ε 2 + ε 2 = ε . {\displaystyle |S(P,f)-(b-a)|<2\delta (a)+2\delta (b)={\frac {\varepsilon }{2}}+{\frac {\varepsilon }{2}}=\varepsilon .} Thus f {\displaystyle f} is McShane integrable and ∫ a b f = b − a . {\displaystyle \int _{a}^{b}f=b-a.} The next example proves the existence of a distinction between Rieman and McShane integrals.
Glossary of geography terms (A–M) M Glossary_of_geography_terms_(A–M) > M mapping The process of designing, drawing, or creating a map. The term is used in particular to refer to the application of cartographic techniques in order to make planimetric or topographic maps, but may also be used for any map, and in the broadest sense may refer to the gathering of geographical data of any kind. march Also marche or mark; (pl.)
Static password Zero-knowledge password proofs Static_password > Factors in the security of a password system > Methods of verifying a password over a network > Zero-knowledge password proofs Rather than transmitting a password, or transmitting the hash of the password, password-authenticated key agreement systems can perform a zero-knowledge password proof, which proves knowledge of the password without exposing it. Moving a step further, augmented systems for password-authenticated key agreement (e.g., AMP, B-SPEKE, PAK-Z, SRP-6) avoid both the conflict and limitation of hash-based methods. An augmented system allows a client to prove knowledge of the password to a server, where the server knows only a (not exactly) hashed password, and where the un-hashed password is required to gain access.
Whipple procedure Pylorus-sparing pancreaticoduodenectomy Whipple_procedure > Surgical considerations > Pylorus-sparing pancreaticoduodenectomy The main advantage of this technique is that the pylorus, and thus normal gastric emptying, should in theory be preserved. There is conflicting data as to whether pylorus-preserving pancreaticoduodenectomy is associated with increased likelihood of gastric emptying. In practice, it shows similar long-term survival as a Whipple's (pancreaticoduodenectomy + hemigastrectomy), but patients benefit from improved recovery of weight after a PPPD, so this should be performed when the tumour does not involve the stomach and the lymph nodes along the gastric curvatures are not enlarged.Compared to the standard Whipple procedure, the pylorus preserving pancreaticoduodenectomy technique is associated with shorter operation time and less intraoperative blood loss, requiring less blood transfusion. Post-operative complications, hospital mortality and survival do not differ between the two methods.
Ray (geometry) Linear equation Euclidean_line > Definition > Linear equation One can further suppose either c = 1 or c = 0, by dividing everything by c if it is not zero. There are many variant ways to write the equation of a line which can all be converted from one to another by algebraic manipulation. The above form is sometimes called the standard form.
Parallel all-pairs shortest path algorithm Parallelization for more than |V| processors Parallel_all-pairs_shortest_path_algorithm > Dijkstra algorithm > Parallelization for more than |V| processors The idea for this parallelization is to distribute the management of the distancelist d v {\displaystyle d_{v}} in DijkstraSSSP within the partition. Each processor in the partition therefore is exclusively responsible for | V | k {\displaystyle {\frac {|V|}{k}}} elements of d v {\displaystyle d_{v}} . For example, consider | V | = 4 {\displaystyle |V|=4} and p = 8 {\displaystyle p=8}: this yields a partition size of k = 2 {\displaystyle k=2} .
DNIX Summary DNIX DNIX (original spelling: D-Nix) is a discontinued Unix-like real-time operating system from the Swedish company Dataindustrier AB (DIAB). A version named ABCenix was developed for the ABC 1600 computer from Luxor. Daisy Systems also had a system named Daisy DNIX on some of their computer-aided design (CAD) workstations. It was unrelated to DIAB's product.
Central nervous system depressant Opioids/Opiates CNS_depressant > Types > Opioids/Opiates It plays a major role in the development of tolerance to μ-opioid agonists.When "pain" occurs, a signal gets sent from the site of possible injury. This signal goes up the spinal cord into the brain where it is perceived as a negative emotion known as nociception or "hurt". In the central nervous system, the spine is connected to the brain by a structure called the brain stem.
Vertical Loop History Clothoid_loop > History Later attempts to build a looping roller coaster were carried out during the late 19th century with the Flip Flap Railway at Sea Lion Park. The ride was designed with a completely circular loop (rather than the teardrop shape used by many modern looping roller coasters), and caused neck injuries due to the intense G-forces pulled with the tight radius of the loop.The next attempt at building a looping roller coaster was in 1901 when Edwin Prescott built the Loop the Loop at Coney Island. This ride used the modern teardrop-shaped loop and a steel structure, however more people wanted to watch the attraction, rather than ride.