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Catalyst Inhibitors, poisons, and promoters Catalyst > Inhibitors, poisons, and promoters Without the deactivation of the catalyst, the alkene produced would be further hydrogenated to alkane.The inhibitor can produce this effect by, e.g., selectively poisoning only certain types of active sites. Another mechanism is the modification of surface geometry. For instance, in hydrogenation operations, large planes of metal surface function as sites of hydrogenolysis catalysis while sites catalyzing hydrogenation of unsaturates are smaller.
Social exchange theory Power dependence relations Social_exchange_theory > Modes of exchange > Power dependence relations Several definitions of power have been offered by exchange theorists. For instance, some theorists view power as distinct from exchanges, some view it as a kind of exchange and others believe power is a medium of exchange. However, the most useful definition of power is that proposed by Emerson, who developed a theory of power-dependence relations. According to this theory, the dependence a person has on another brings up the concept of power.
Procalcitonin Meningitis Procalcitonin > Medical uses > Meningitis It can also be of use in determining viral meningitis versus bacterial meningitis. These findings are the result of a 2018 literature review. This followed a 2015 meta analysis that showed that PCT had a sensitivity of 90% and a specificity of 98% in judging viral versus bacterial meningitis. PCT also outperformed other biomarkers such as C-reactive protein.
Instruction Set Simulator Implementation Instruction_Set_Simulator > Implementation This only works for same-on-same instruction-set simulation, such as running x86 simulators on x86 hosts, or ARM simulators on ARM hosts.An ISS is often provided with (or is itself) a debugger in order for a software engineer/programmer to debug the program prior to obtaining target hardware. GDB is one debugger which has a compiled-in ISS. It is sometimes integrated with simulated peripheral circuits such as timers, interrupts, serial ports, general I/O ports, etc. to mimic the behavior of a microcontroller.
Natural gas reserves Resource estimates Gas_reserves > Reserves and resource reporting > Resource estimates Resource estimates are undiscovered volumes, or volumes that have not yet been drilled and flowed to surface. A non-reserve resource, by definition, does not have to be technically or commercially recoverable and can be represented by a single, or an aggregate of multiple potential accumulations, e.g. an estimated geological basin resource. There are two non-reserve resource categories:
Function evaluation Functional notation Bivariate_function > Notation > Functional notation In functional notation, the function is immediately given a name, such as f {\displaystyle f} , and its definition is given by what f {\displaystyle f} does to the explicit argument x {\displaystyle x} , using a formula in terms of x {\displaystyle x} . For example, the function which takes a real number as input and outputs that number plus 1 is denoted by f ( x ) = x + 1 {\displaystyle f(x)=x+1} .If a function is defined in this notation, its domain and codomain are implicitly taken to both be R {\displaystyle \mathbb {R} } , the set of real numbers. If the formula cannot be evaluated at all real numbers, then the domain is implicitly taken to be the maximal subset of R {\displaystyle \mathbb {R} } on which the formula can be evaluated; see Domain of a function. A more complicated example is the function f ( x ) = sin ⁡ ( x 2 + 1 ) {\displaystyle f(x)=\sin(x^{2}+1)} .In this example, the function f takes a real number as input, squares it, then adds 1 to the result, then takes the sine of the result, and returns the final result as the output.
Gene cluster Summary Gene_cluster A gene family is a set of homologous genes within one organism. A gene cluster is a group of two or more genes found within an organism's DNA that encode similar polypeptides, or proteins, which collectively share a generalized function and are often located within a few thousand base pairs of each other. The size of gene clusters can vary significantly, from a few genes to several hundred genes. Portions of the DNA sequence of each gene within a gene cluster are found to be identical; however, the resulting protein of each gene is distinctive from the resulting protein of another gene within the cluster. Genes found in a gene cluster may be observed near one another on the same chromosome or on different, but homologous chromosomes. An example of a gene cluster is the Hox gene, which is made up of eight genes and is part of the Homeobox gene family.
Chemotherapy Treatment strategies Chemotherapy > Treatment strategies : 55–59 It is also useful in killing any cancerous cells that have spread to other parts of the body. These micrometastases can be treated with adjuvant chemotherapy and can reduce relapse rates caused by these disseminated cells.
Subderivative The subgradient Subderivative > The subgradient The set of all subgradients at x 0 {\displaystyle x_{0}} is called the subdifferential at x 0 {\displaystyle x_{0}} and is again denoted ∂ f ( x 0 ) {\displaystyle \partial f(x_{0})} . The subdifferential is always a convex closed set. It can be an empty set; consider for example an unbounded operator, which is convex, but has no subgradient. If f {\displaystyle f} is continuous, the subdifferential is nonempty.
Nerve guidance conduit Ectomesenchymal stem cells Nerve_guidance_conduits > Cellular therapies > Stem cells > Ectomesenchymal stem cells They can be thought of as Schwann progenitor cells because they are associated with dorsal root ganglion and motor nerve development. EMSC differentiation appears to be regulated by intrinsic genetic programs and extracellular signals in the surrounding environment. Schwann cells are the source for both neurotropic and neurotrophic factors essential for regenerating nerves and a scaffold for guiding growth.
Falling (sensation) Summary Falling_(sensation) The vestibular apparatus also detects spatial orientation with respect to visual input. A similar sensation of falling can be induced when the eyes detect rapid apparent motion with respect to the environment. This system enables people to keep their balance by signalling when a physical correction is necessary. Some medical conditions, known as balance disorders, also induce the sensation of falling. In the early stages of sleep, a falling sensation may be perceived in connection with a hypnic jerk, sometimes awaking the sleeper abruptly.
Approximate Bayesian Computation Choice and sufficiency of summary statistics Approximate_Bayesian_Computation > Pitfalls and remedies > Choice and sufficiency of summary statistics Methods for the identification of summary statistics that could also simultaneously assess the influence on the approximation of the posterior would be of substantial value. This is because the choice of summary statistics and the choice of tolerance constitute two sources of error in the resulting posterior distribution. These errors may corrupt the ranking of models and may also lead to incorrect model predictions. Indeed, none of the methods above assesses the choice of summaries for the purpose of model selection.
Poisson’s equation Electrostatics Poisson's_Equation > Electrostatics The derivation of Poisson's equation under these circumstances is straightforward. Substituting the potential gradient for the electric field, directly produces Poisson's equation for electrostatics, which is Solving Poisson's equation for the potential requires knowing the charge density distribution. If the charge density is zero, then Laplace's equation results.
Influence machine Summary Electrostatic_machine An electrostatic generator, or electrostatic machine, is an electrical generator that produces static electricity, or electricity at high voltage and low continuous current. The knowledge of static electricity dates back to the earliest civilizations, but for millennia it remained merely an interesting and mystifying phenomenon, without a theory to explain its behavior and often confused with magnetism. By the end of the 17th century, researchers had developed practical means of generating electricity by friction, but the development of electrostatic machines did not begin in earnest until the 18th century, when they became fundamental instruments in the studies about the new science of electricity. Electrostatic generators operate by using manual (or other) power to transform mechanical work into electric energy, or using electric currents. Manual electrostatic generators develop electrostatic charges of opposite signs rendered to two conductors, using only electric forces, and work by using moving plates, drums, or belts to carry electric charge to a high potential electrode.
Velocity Prediction Program Methodology Velocity_Prediction_Program > Methodology VPPs are iterative programs which require educated guesses of initial parameters to begin operating. Generally VPPs are composed of two mechanisms, a boat model and a solution algorithm. Initial guesses of parameters including boat speed (Vs), heel angle (Φ), number of reefs and sail flatness are input into the boat model. Using these input parameters the solution algorithm calculates the difference between the propulsive force of the sails and the resistive force of the hull. It also calculates the righting moment created by the hull and the operational heel angle. Since the propulsive force and the resistive force are not likely to be equal on the first iteration, the solution algorithm has the responsibility of adjusting the input parameters and balancing the forces until it produces the maximum possible speed at each true wind angle.
Hereditary nonpolyposis colorectal cancer Risk of cancer Hereditary_nonpolyposis_colorectal_cancer > Signs and symptoms > Risk of cancer Lifetime risk and mean age at diagnosis for Lynch syndrome associated cancers In addition to the types of cancer found in the chart above, it is understood that Lynch syndrome also contributes to an increased risk of small bowel cancer, pancreatic cancer, ureter/renal pelvis cancer, biliary tract cancer, brain cancer, and sebaceous neoplasms. Increased risk of prostate cancer and breast cancer has also been associated with Lynch syndrome, although this relationship is not entirely understood.Two-thirds of colon cancers occur in the proximal colon and common signs and symptoms include blood in the stool, diarrhea or constipation, and unintended weight loss. The mean age of colorectal cancer diagnosis is 44 for members of families that meet the Amsterdam criteria. The average age of diagnosis of endometrial cancer is about 46 years.
Learning classifier system Advantages Classifier_system > Advantages Ensemble Learner: No single model is applied to a given instance that universally provides a prediction. Instead a relevant and often conflicting set of rules contribute a 'vote' which can be interpreted as a fuzzy prediction. Stochastic Learner: Non-deterministic learning is advantageous in large-scale or high complexity problems where deterministic or exhaustive learning becomes intractable.
IUPAC nomenclature of inorganic chemistry Simple ionic compounds Inorganic_nomenclature > Traditional naming > Simple ionic compounds An ionic compound is named by its cation followed by its anion. See polyatomic ion for a list of possible ions. For cations that take on multiple charges, the charge is written using Roman numerals in parentheses immediately following the element name. For example, Cu(NO3)2 is copper(II) nitrate, because the charge of two nitrate ions (NO−3) is 2 × −1 = −2, and since the net charge of the ionic compound must be zero, the Cu ion has a 2+ charge.
Chemical yield Theoretical, actual, and percent yields Yield_(chemistry) > Theoretical, actual, and percent yields According to Whitten, the actual yield is always smaller (the percent yield is less than 100%), often very much so, for several reasons. : 95 As a result, many reactions are incomplete and the reactants are not completely converted to products.
Volumetric analysis Redox titrations Back_titration > Particular uses > Redox titrations During this type of titration, glucose reduces cupric ions to cuprous ions which react with potassium thiocyanate to produce a white precipitate, indicating the endpoint. Bromine number: A measure of unsaturation in an analyte, expressed in milligrams of bromine absorbed by 100 grams of sample. Iodine number: A measure of unsaturation in an analyte, expressed in grams of iodine absorbed by 100 grams of sample.
Growth velocity Quantitative definitions Growth_chart > Quantitative definitions Alternatively, TH can be expressed in standard deviation scores (SDS), with TH_SDS = (mother’s height_SDS + father’s height_SDS) / 2. Yet, this calculation is incorrect as it needs adjustment to mid-population height. It is suggested to use the conditional target height or cTH_SDS with a correction factor of 0.72.cTH_SDS = TH_SDS x 0.72 Velocity is another quantity that is used to quantify growth curves.
Ion Optics Multipole lenses Electrostatic_lens > Multipole lenses Multipoles beyond the quadrupole can correct for spherical aberration and in particle accelerators the dipole bending magnets are really composed of a large number of elements with different superpositions of multipoles. Usually the dependency is given for the kinetic energy itself depending on the power of the velocity. So for an electrostatic lens the focal length varies with the second power of the kinetic energy, while for a magnetostatic lens the focal length varies proportional to the kinetic energy.
Functional polymers Classification and chemistry Smart_polymer > Classification and chemistry Hydrophilic, amorphous, low-molecular-weight polymers containing heteroatoms (i.e., atoms other than carbon) have been found to degrade fastest. Scientists control the rate of drug delivery by varying these properties thus adjusting the rate of degradation.
Predictive engineering analytics The use of new materials and manufacturing methods Predictive_engineering_analytics > Industry needs > The use of new materials and manufacturing methods To achieve reduced costs or fuel economy, manufacturers need to continually consider adopting new materials and corresponding manufacturing methods. That makes product development more complex, as engineers cannot rely on their decades of experience anymore, like they did when working with traditional materials, such as steel and aluminium, and traditional manufacturing methods, such as casting. New materials such as composites, behave differently when it comes to structural behavior, thermal behavior, fatigue behavior or noise insulation for example, and require dedicated modeling. On top of that, as design engineers do not always know all manufacturing complexities that come with using these new materials, it is possible that the "product as manufactured" is different from the "product as designed". Of course all changes need to be tracked, and possibly even an extra validation iteration needs to be done after manufacturing.
Open problems in physics Philosophy of physics Open_problems_in_physics > Philosophy of physics Interpretation of quantum mechanics: How does the quantum description of reality, which includes elements such as the superposition of states and wavefunction collapse or quantum decoherence, give rise to the reality we perceive? Another way of stating this question regards the measurement problem: What constitutes a "measurement" which apparently causes the wave function to collapse into a definite state? Unlike classical physical processes, some quantum mechanical processes (such as quantum teleportation arising from quantum entanglement) cannot be simultaneously "local", "causal", and "real", but it is not obvious which of these properties must be sacrificed, or if an attempt to describe quantum mechanical processes in these senses is a category error such that a proper understanding of quantum mechanics would render the question meaningless.
Mir-19 microRNA precursor family Expression Mir-19_microRNA_precursor_family > Expression MiR-17-92 cluster was identified to encode 6 single mature miRNA (miR-17, , miR-19, miR-20, miR-92, miR-106) containing the first oncogenic miRNA. MicroRNA from miR-19 family can be expressed from: * T-cell acute lymphoblastic leukemia * B-cell lymphomas * Cell lines * Cerebellum * Purkinje cells * HeLa cellsFinally they have tissues-specific miRNA expression. These microRNA are considered as oncogenes which improve proliferation, inhibits apoptosis and induce tumor angiogenesis. These miRNA are context-specific and they have different roles depending on where they are.
Nucleopore filter Summary Nucleopore_filter A nuclepore filter (brand name Nuclepore from Whatman, part of GE Healthcare) is a kind of filter in which holes a few micrometres in size have been created in a plastic (e.g. polycarbonate) membrane. These filters are generally created by exposing the membrane to radiation that weakens the plastic and creates specific areas that can be removed by dousing the membrane in acid (or other chemicals). The technique and patent were developed by Robert L. Fleischer, P. Buford Price, and Robert M. Walker as an outgrowth of their research on radiation effects in solids, with a special focus on materials exposed to energetic particles in space. The technique allows for creating uniform holes of any desired diameter to allow even a virus to be filtered. The most common use of Nuclepore filters is in microbiology where they are used to trap cells while removing all other fluids and smaller particles, e.g. for counting bacteria by fluorescence microscopy. Because the filters have a flat surface, the cells are trapped on top of the filter and remain visible, unlike other types of filters where the cells may be trapped inside the filter.
Neurogenic shock Pathophysiology Neurogenic_shock > Pathophysiology Neurogenic shock is diagnosed based on a person's symptoms and blood pressure levels. Neurogenic shock's presentation includes:- warm and pink skin - labored breathing - low blood pressure - dizziness - anxiety - history of trauma to head or upper spine. - if the injury is to the head or neck, hoarseness or difficulty swallowing may occur. Symptoms of neurogenic shock are differentiated from other forms of shock by the lack of signs of the compensatory mechanisms triggered by the SNS, usual in other forms of shock.
Mir-7 microRNA precursor Summary Mir-7_microRNA_precursor This family represents the microRNA (miRNA) precursor mir-7. This miRNA has been predicted or experimentally confirmed in a wide range of species. miRNAs are transcribed as ~70 nucleotide precursors (modelled here) and subsequently processed by the Dicer enzyme to give a ~22 nucleotide product. In this case the mature sequence comes from the 5' arm of the precursor.
Electrocatalyst Background and theory Electrocatalyst > Background and theory Selectivity can be quantitatively assessed through a selectivity coefficient, which compares the response of the material to the desired analyte or substrate with the response to other interferents.In many electrochemical systems, including galvanic cells, fuel cells and various forms of electrolytic cells, a drawback is that they can suffer from high activation barriers. The energy diverted to overcome these activation barriers is transformed into heat. In most exothermic combustion reactions this heat would simply propagate the reaction catalytically.
Regular semantics Summary Regular_semantics Regular semantics is a computing term which describes one type of guarantee provided by a data register shared by several processors in a parallel machine or in a network of computers working together. Regular semantics are defined for a variable with a single writer but multiple readers. These semantics are stronger than safe semantics but weaker than atomic semantics: they guarantee that there is a total order to the write operations which is consistent with real-time and that read operations return either the value of the last write completed before the read begins, or that of one of the writes which are concurrent with the read.
NitrosBase Implementation details NitrosBase > Implementation details The internal graph model is close to RDF* which is used in Blazegraph and Amazon Neptune. That allows it to treat the internal data graph both as RDF graph and as Property Graph, performing queries both in SPARQL and Gremlin-style languages. Instead of indexes based on B+-trees traditionally used in graph databases, NitrosBase uses a sparse link index of its own devising. Another source of performance gain is storage optimization on the physical level in order to reduce the number of random access operations. Like memSQL, NitrosBase translates a query into C++ code.
Object composition Programming technique Object_composition > Programming technique Object-oriented programming is based on objects to encapsulate data and behavior. It uses two main techniques for assembling and composing functionality into more complex ones, sub-typing and object composition. Object composition is about combining objects within compound objects, and at the same time, ensuring the encapsulation of each object by using their well-defined interface without visibility of their internals. In this regard, object composition differs from data structures, which do not enforce encapsulation.
Cancer epigenetics Histone modification Cancer_epigenetics > Mechanisms > Histone modification In this field, there is growing interest in mapping changes in histone modifications and their possible consequences.DNA damage, caused by UV light, ionizing radiation, environmental toxins, and metabolic chemicals, can also lead to genomic instability and cancer. The DNA damage response to double strand DNA breaks (DSB) is mediated in part by histone modifications. At a DSB, MRE11-RAD50-NBS1 (MRN) protein complex recruits ataxia telangiectasia mutated (ATM) kinase which phosphorylates Serine 129 of Histone 2A.
Mood disturbance Depressive disorders Mood_disorder > Classification > Depressive disorders Depressive personality disorder is currently described in Appendix B in the DSM-IV-TR as worthy of further study.Recurrent brief depression (RBD), distinguished from major depressive disorder primarily by differences in duration. People with RBD have depressive episodes about once per month, with individual episodes lasting less than two weeks and typically less than 2–3 days. Diagnosis of RBD requires that the episodes occur over the span of at least one year and, in female patients, independently of the menstrual cycle. People with clinical depression can develop RBD, and vice versa and both illnesses have similar risks.Minor depressive disorder, or simply minor depression, which refers to a depression that does not meet full criteria for major depression but in which at least two symptoms are present for two weeks.
Evaluation Standards Evaluation > Standards Such review is required of significant (determined in terms of cost or sensitivity) evaluations. The review is based on quality of work and the degree to which a demonstrable link is provided between findings and recommendations. Transparency requires that stakeholders are aware of the reason for the evaluation, the criteria by which evaluation occurs and the purposes to which the findings will be applied.
Third law of thermodynamics Systems with non-zero entropy at absolute zero Third_law_of_thermodynamics > Explanation > Systems with non-zero entropy at absolute zero Only ferromagnetic, antiferromagnetic, and diamagnetic materials can satisfy this condition. However, ferromagnetic materials do not, in fact, have zero entropy at zero temperature, because the spins of the unpaired electrons are all aligned and this gives a ground-state spin degeneracy. Materials that remain paramagnetic at 0 K, by contrast, may have many nearly degenerate ground states (for example, in a spin glass), or may retain dynamic disorder (a quantum spin liquid).
Tuberculous pericarditis Summary Tuberculous_pericarditis Tuberculous pericarditis is a form of pericarditis. Pericarditis caused by tuberculosis is difficult to diagnose, because definitive diagnosis requires culturing Mycobacterium tuberculosis from aspirated pericardial fluid or pericardial biopsy, which requires high technical skill and is often not diagnostic (the yield from culture is low even with optimum specimens). The Tygerberg scoring system helps the clinician to decide whether pericarditis is due to tuberculosis or whether it is due to another cause: night sweats (1 point), weight loss (1 point), fever (2 point), serum globulin > 40g/L (3 points), blood total leucocyte count <10 x 109/l (3 points); a total score of 6 or more is highly suggestive of tuberculous pericarditis.
Policy iteration Constrained Markov decision processes Markov_Decision_Processes > Constrained Markov decision processes Constrained Markov decision processes (CMDPS) are extensions to Markov decision process (MDPs). There are three fundamental differences between MDPs and CMDPs. There are multiple costs incurred after applying an action instead of one.
Mammary ductal carcinoma Staging Mammary_ductal_carcinoma > Diagnosis > Staging Pathologic staging is considered more accurate, but clinical staging can give useful information to determine treatment plans prior to surgical efforts. Both clinical and pathologic staging use the TNM staging system, which take into account the tumor size (T), lymph node involvement (N), and evidence of metastasis (M). The TNM staging system designed for breast cancer is shown in the table below.
C Language "Hello, world" example C_Language > "Hello, world" example The closing curly brace indicates the end of the code for the main function. According to the C99 specification and newer, the main function, unlike any other function, will implicitly return a value of 0 upon reaching the } that terminates the function. (Formerly an explicit return 0; statement was required.) This is interpreted by the run-time system as an exit code indicating successful execution.
Secure multiparty computation Two-party computation Secure_multi-party_computation > Protocols > Two-party computation The function is viewed as a Boolean circuit, with inputs in binary of fixed length. A Boolean circuit is a collection of gates connected with three different types of wires: circuit-input wires, circuit-output wires and intermediate wires. Each gate receives two input wires and it has a single output wire which might be fan-out (i.e. be passed to multiple gates at the next level).
Laser Doppler anemometry Operating principles Laser_Doppler_velocimetry > Operating principles Particles passing through this volume will scatter light from the measurement beam with a Doppler shift; a portion of this light is collected by the receiving optics and transferred to the photodetector. The reference beam is also sent to the photodetector where optical heterodyne detection produces an electrical signal proportional to the Doppler shift, by which the particle velocity component perpendicular to the plane of the beams can be determined.The signal detection scheme of the instrument is using the principle of optical heterodyne detection. This principle is similar to other laser Doppler-based instruments such as laser Doppler vibrometer, or laser surface velocimeter. It is possible to apply digital techniques to the signal to obtain the velocity as a measured fraction of the speed-of-light, and therefore in one sense Laser Doppler velocimetry is a particularly fundamental measurement traceable to the S.I. system of measurement.
Probability Applications Probability > Applications The theory of behavioral finance emerged to describe the effect of such groupthink on pricing, on policy, and on peace and conflict.In addition to financial assessment, probability can be used to analyze trends in biology (e.g., disease spread) as well as ecology (e.g., biological Punnett squares). As with finance, risk assessment can be used as a statistical tool to calculate the likelihood of undesirable events occurring, and can assist with implementing protocols to avoid encountering such circumstances. Probability is used to design games of chance so that casinos can make a guaranteed profit, yet provide payouts to players that are frequent enough to encourage continued play.Another significant application of probability theory in everyday life is reliability. Many consumer products, such as automobiles and consumer electronics, use reliability theory in product design to reduce the probability of failure. Failure probability may influence a manufacturer's decisions on a product's warranty.The cache language model and other statistical language models that are used in natural language processing are also examples of applications of probability theory.
Water gas shift reaction Reaction conditions Water_gas_shift_reaction > Reaction conditions The equilibrium of this reaction shows a significant temperature dependence and the equilibrium constant decreases with an increase in temperature, that is, higher hydrogen formation is observed at lower temperatures.
Pseudobulbar affect Multiple sclerosis Pseudobulbar_affect > Causes > Multiple sclerosis Recent studies suggest that approximately 10% of patients with multiple sclerosis (MS) will experience at least one episode of emotional lability. PBA is generally associated with later stages of the disease (chronic progressive phase). PBA in MS patients is associated with more severe intellectual deterioration, physical disability, and neurological disability.
Trajectory inference Dimensionality Reduction Trajectory_inference > Methods > Dimensionality Reduction The data produced by single-cell RNA-seq can consist of thousands of cells each with expression levels recorded across thousands of genes. In order to efficiently process data with such high dimensionality many trajectory inference algorithms employ a dimensionality reduction procedure such as principal component analysis (PCA), independent component analysis (ICA), or t-SNE as their first step. The purpose of this step is to combine many features of the data into a more informative measure of the data. For example, a coordinate resulting from dimensionality reduction could combine expression levels from many genes that are associated with the cell cycle into one value that represents a cell's position in the cell cycle. Such a transformation corresponds to dimensionality reduction in the feature space, but dimensionality reduction can also be applied to the sample space by clustering together groups of similar cells.
Telomerase reverse transcriptase Regulation Telomerase_reverse_transcriptase > Regulation Another form of up-regulation is through demethylation of histones proximal to the promoter region, imitating the low density of trimethylated histones seen in embryonic stem cells. This allows for the recruitment of histone acetyltransferase (HAT) to unwind the sequence allowing for transcription of the gene.Telomere deficiency is often linked to aging, cancers and the conditions dyskeratosis congenita (DKC) and Cri du chat. Meanwhile, over-expression of hTERT is often associated with cancers and tumor formation. The regulation of hTERT is extremely important to the maintenance of stem and cancer cells and can be used in multiple ways in the field of regenerative medicine.
Magnetic diffusion Equation Magnetic_diffusion > Equation The latter acts as a dissipation term, resulting in a loss of magnetic field energy to heat. The relative importance of the two terms is characterized by the magnetic Reynolds number, R m {\displaystyle R_{m}} . In the case of a non-uniform conductivity the magnetic diffusion equation is however, it becomes significantly harder to solve.
Chronic stress Symptoms Chronic_stress > Symptoms People may experience anxiety, depression, sadness, anger, irritability, social isolation, headache, menstrual problems, abdominal pain, back pain and difficulty concentrating.
Arachidonic acid Brain Arachidonic_acid > In the body > Brain Among other things, arachidonic acid helps to maintain hippocampal cell membrane fluidity. It also helps protect the brain from oxidative stress by activating peroxisome proliferator-activated receptor gamma. AA also activates syntaxin-3 (STX-3), a protein involved in the growth and repair of neurons.Arachidonic acid is also involved in early neurological development.
Glycogen synthase Regulation Glycogen_synthase > Regulation The enzyme also cleaves the ester bond between the C1 position of glucose and the pyrophosphate of UDP itself. The control of glycogen synthase is a key step in regulating glycogen metabolism and glucose storage. Glycogen synthase is directly regulated by glycogen synthase kinase 3 (GSK-3), AMPK, protein kinase A (PKA), and casein kinase 2 (CK2).
Distributed processing Models Distributed_processing > Theoretical foundations > Models Many tasks that we would like to automate by using a computer are of question–answer type: we would like to ask a question and the computer should produce an answer. In theoretical computer science, such tasks are called computational problems. Formally, a computational problem consists of instances together with a solution for each instance. Instances are questions that we can ask, and solutions are desired answers to these questions.
Stackdriver Summary Stackdriver Google Stackdriver was a cloud computing systems management service offered by Google. It provided performance and diagnostics data (in the form of monitoring, logging, tracing, error reporting, and alerting) to public cloud users. Stackdriver was a multi-cloud solution, providing support for both Google Cloud and AWS cloud environments. Google ended use of the Stackdriver brand in February 2020.
Monte-Carlo method Monte Carlo and random numbers Monte-Carlo_simulation > Definitions > Monte Carlo and random numbers What this means depends on the application, but typically they should pass a series of statistical tests. Testing that the numbers are uniformly distributed or follow another desired distribution when a large enough number of elements of the sequence are considered is one of the simplest and most common ones. Weak correlations between successive samples are also often desirable/necessary.
Thermosynthesis Summary Thermosynthesis Thermosynthesis is a theoretical mechanism proposed by Anthonie Muller for biological use of the free energy in a temperature gradient to drive energetically uphill anabolic reactions. It makes use of this thermal gradient, or the dissipative structure of convection in this gradient, to drive a microscopic heat engine that performs condensation reactions. Thus negative entropy is generated. The components of the biological thermosynthesis machinery concern progenitors of today's ATP synthase, which functions according to the binding change mechanism, driven by chemiosmosis.
Eye tracker Commercial eye tracking Eye_tracker > References > Commercial eye tracking Pieters, R.; Wedel, M. (2007). "Goal Control of Visual Attention to Advertising: The Yarbus Implication". Journal of Consumer Research.
Torsional rigidity Relationship to elasticity Stiffness > Relationship to elasticity The elastic modulus of a material is not the same as the stiffness of a component made from that material. Elastic modulus is a property of the constituent material; stiffness is a property of a structure or component of a structure, and hence it is dependent upon various physical dimensions that describe that component. That is, the modulus is an intensive property of the material; stiffness, on the other hand, is an extensive property of the solid body that is dependent on the material and its shape and boundary conditions. For example, for an element in tension or compression, the axial stiffness is where E {\displaystyle E} is the (tensile) elastic modulus (or Young's modulus), A {\displaystyle A} is the cross-sectional area, L {\displaystyle L} is the length of the element.Similarly, the torsional stiffness of a straight section is where G {\displaystyle G} is the rigidity modulus of the material, J {\displaystyle J} is the torsion constant for the section.Note that the torsional stiffness has dimensions * / , so that its SI units are N*m/rad. For the special case of unconstrained uniaxial tension or compression, Young's modulus can be thought of as a measure of the stiffness of a structure.
Interlimb coordination Parkinson's disease Interlimb_coordination > Future medical application related to interlimb coordination > Parkinson's disease Furthermore, repeated adaptations of the gait pattern may improve the flexible adaptation of the movement to new tasks and may train motor switching, which could potentially improve motor performance in a more sustained manner. In addition, the cerebellar circuits became more involved in the processing of gait adaptation with repeated exposure to SBT, which may possibly lead to improvement in balancing and hence reduce the risk of falling. == References ==
Isaac Newton Gravity Isaac_Newton > Mid-life > Gravity In 1679, Newton returned to his work on celestial mechanics by considering gravitation and its effect on the orbits of planets with reference to Kepler's laws of planetary motion. This followed stimulation by a brief exchange of letters in 1679–80 with Hooke, who had been appointed to manage the Royal Society's correspondence, and who opened a correspondence intended to elicit contributions from Newton to Royal Society transactions. Newton's reawakening interest in astronomical matters received further stimulus by the appearance of a comet in the winter of 1680–1681, on which he corresponded with John Flamsteed. After the exchanges with Hooke, Newton worked out a proof that the elliptical form of planetary orbits would result from a centripetal force inversely proportional to the square of the radius vector.
Pulmonary oedema Non-cardiogenic Pulmonary_oedema > Types > Non-cardiogenic Neurogenic causes (seizures, head trauma, strangulation, electrocution). Pulmonary embolismAcute lung injury may also cause pulmonary edema directly through injury to the vasculature and parenchyma of the lung. It includes acute lung injury and acute respiratory distress syndrome.
Quantum limit Displacement measurement Standard_quantum_limit > Examples > Displacement measurement }} due to back action also satisfy the uncertainty relation: Δ x m e a s Δ p b . a . ≥ ℏ 2 .
History of cell membrane theory Fluid mosaic model History_of_cell_membrane_theory > Fluid mosaic model They fused two cells labeled with different membrane-bound fluorescent tags and watched as the two dye populations mixed. The results of this experiment were key in the development of the "fluid mosaic" model of the cell membrane by Singer and Nicolson in 1972. According to this model, biological membranes are composed largely of bare lipid bilayer with proteins penetrating either half way or all the way through the membrane.
Trophic function Summary Trophic_function In economics, "predator" and "prey" become various economic parameters such as prices and outputs of goods in various linked sectors such as processing and supply. These relationships, in turn, were found to behave similarly to the magnitudes in chemical kinetics, where the molecular analogues of predators and prey react chemically with each other. These inter-disciplinary findings suggest the universal character of trophic functions and the predator–prey models in which they appear.
Linear probing Choice of hash function Linear_probing > Choice of hash function The numbers from those table cells are then combined by a bitwise exclusive or operation. Hash functions constructed this way are only 3-independent. Nevertheless, linear probing using these hash functions takes constant expected time per operation.
DOT pictograms Summary DOT_pictograms The DOT pictograms are a set of fifty pictograms used to convey information useful to travelers without using words. Such images are often used in airports, train stations, hotels, and other public places for foreign tourists, as well as being easier to identify than strings of text. Among these pictograms are graphics representing toilets and telephones. As a result of their near-universal acceptance, some describe them as the "Helvetica" of pictograms, and the character portrayed within them as Helvetica Man.As works of the United States government, the images are in the public domain and thus can be used by anyone for any purpose, without licensing issues.
Pathology Histopathology Pathology > General pathology > Anatomical pathology > Histopathology To see the tissue under a microscope, the sections are stained with one or more pigments. The aim of staining is to reveal cellular components; counterstains are used to provide contrast. Histochemistry refers to the science of using chemical reactions between laboratory chemicals and components within tissue. The histological slides are then interpreted diagnostically and the resulting pathology report describes the histological findings and the opinion of the pathologist. In the case of cancer, this represents the tissue diagnosis required for most treatment protocols.
Digital integrated circuit History Digital_circuits > History The MOSFET's advantages include high scalability, affordability, low power consumption, and high transistor density. Its rapid on–off electronic switching speed also makes it ideal for generating pulse trains, the basis for electronic digital signals, in contrast to BJTs which, more slowly, generate analog signals resembling sine waves.
Asymptotology Principles Asymptotology > Principles The field of asymptotics is normally first encountered in school geometry with the introduction of the asymptote, a line to which a curve tends at infinity. The word Ασύμπτωτος (asymptotos) in Greek means non-coincident and puts strong emphasis on the point that approximation does not turn into coincidence. It is a salient feature of asymptotics, but this property alone does not entirely cover the idea of asymptotics and, etymologically, the term seems to be quite insufficient.
Distributed Hash Table Overlay network Distributed_Hash_Table > Structure > Overlay network All DHT topologies share some variant of the most essential property: for any key k, each node either has a node ID that owns k or has a link to a node whose node ID is closer to k, in terms of the keyspace distance defined above. It is then easy to route a message to the owner of any key k using the following greedy algorithm (that is not necessarily globally optimal): at each step, forward the message to the neighbor whose ID is closest to k. When there is no such neighbor, then we must have arrived at the closest node, which is the owner of k as defined above. This style of routing is sometimes called key-based routing.
QuakeC Modified compilers and language extensions QuakeC > Modified compilers and language extensions In 1999, when id Software released the code from Quake's engine under the GNU General Public License (GPL), the workings of the bytecode interpreter were examined and new QuakeC compilers were released, such as J.P. Grossman's qccx and a new version of FrikQCC. These compilers took advantage of newly discovered features in a backwards-compatible way so that the bytecode could still be properly interpreted by unmodified Quake engines.
Coefficient of static friction Coefficient of friction Angle_of_friction > Dry friction > Coefficient of friction The coefficient of friction (COF), often symbolized by the Greek letter µ, is a dimensionless scalar value which equals the ratio of the force of friction between two bodies and the force pressing them together, either during or at the onset of slipping. The coefficient of friction depends on the materials used; for example, ice on steel has a low coefficient of friction, while rubber on pavement has a high coefficient of friction. Coefficients of friction range from near zero to greater than one. The coefficient of friction between two surfaces of similar metals is greater than that between two surfaces of different metals; for example, brass has a higher coefficient of friction when moved against brass, but less if moved against steel or aluminum.For surfaces at rest relative to each other, μ = μ s {\displaystyle \mu =\mu _{\mathrm {s} }} , where μ s {\displaystyle \mu _{\mathrm {s} }} is the coefficient of static friction.
Current Medicinal Chemistry Summary Current_Medicinal_Chemistry Current Medicinal Chemistry is a peer-reviewed medical journal published by Bentham Science Publishers. The editor-in-chief is Atta-ur-Rahman, FRS (Kings College University of Cambridge Cambridge, UK). The journal covers developments in medicinal chemistry and rational drug design and publishes original research reports and review papers.A related journal titled Current Medicinal Chemistry – Anti-Cancer Agents ISSN 1568-0118 was launched in 2001, and retitled as Anti-Cancer Agents in Medicinal Chemistry from the start of 2006 with ISSN 1871-5206 (print), ISSN 1875-5992 (online).
Disc integration Function of y Disc_integration > Definition > Function of y If the function to be revolved is a function of y, the following integral will obtain the volume of the solid of revolution: π ∫ c d R ( y ) 2 d y {\displaystyle \pi \int _{c}^{d}R(y)^{2}\,dy} where R(y) is the distance between the function and the axis of rotation. This works only if the axis of rotation is vertical (example: x = 4 or some other constant).
Soil texture classification Laser Diffraction Soil_texture_classification > Methodology > Laser Diffraction Laser diffraction is a measurement technique for determining the particle size distribution of samples, either dispersed in a liquid or as a dry powder. The technique is based on light waves getting bent when encountering particles in a sample. The measured equivalent spherical diameter is the diameter of a sphere having on the cross-sectional area the same diffraction pattern as the investigated particle.The angle of diffraction depends on the particle size, hence the pattern of diffraction depends on the relative amounts of different particle sizes present in that sample. This diffraction pattern is then detected and analyzed by means of Mie and Fraunhofer diffraction models.
Casimir vacuum Papers, books and lectures Dynamical_Casimir_Effect > Further reading > Papers, books and lectures Downling, J. P. (1989). "The Mathematics of the Casimir Effect".
Least significant digit Relationship to accuracy and precision in measurement Most_significant_digit > Relationship to accuracy and precision in measurement Traditionally, in various technical fields, "accuracy" refers to the closeness of a given measurement to its true value; "precision" refers to the stability of that measurement when repeated many times. Thus, it is possible to be "precisely wrong". Hoping to reflect the way in which the term "accuracy" is actually used in the scientific community, there is a recent standard, ISO 5725, which keeps the same definition of precision but defines the term "trueness" as the closeness of a given measurement to its true value and uses the term "accuracy" as the combination of trueness and precision. (See the accuracy and precision article for a full discussion.) In either case, the number of significant figures roughly corresponds to precision, not to accuracy or the newer concept of trueness.
Graph of desire Graph Graph_of_desire > Graph The graph of desire was first proposed in a 1960 colloquium, and was later published in the Ecrits. It depends on ideas developed originally in Lacan's Schema R, a graph in which fundamental organising structures of the human mind are shown in a schematic relationship to the domains or "orders" which in turn structure human reality: the Imaginary, the Symbolic and the Real. The graph of desire is a "flattened" representation of a signifying chain as it crosses a pathway Lacan called a vector of desire. It appears as two curved lines which cross one another at two separate points. Each line has a symbolic meaning.
Colligative property Osmotic pressure Colligative_Properties > Osmotic pressure The osmotic pressure of a solution is the difference in pressure between the solution and the pure liquid solvent when the two are in equilibrium across a semipermeable membrane, which allows the passage of solvent molecules but not of solute particles. If the two phases are at the same initial pressure, there is a net transfer of solvent across the membrane into the solution known as osmosis. The process stops and equilibrium is attained when the pressure difference equals the osmotic pressure.
Ploidy Haploid and monoploid Ploidy > Types of ploidy > Haploid and monoploid The term haploid is used with two distinct but related definitions. In the most generic sense, haploid refers to having the number of sets of chromosomes normally found in a gamete. Because two gametes necessarily combine during sexual reproduction to form a single zygote from which somatic cells are generated, healthy gametes always possess exactly half the number of sets of chromosomes found in the somatic cells, and therefore "haploid" in this sense refers to having exactly half the number of sets of chromosomes found in a somatic cell. By this definition, an organism whose gametic cells contain a single copy of each chromosome (one set of chromosomes) may be considered haploid while the somatic cells, containing two copies of each chromosome (two sets of chromosomes), are diploid.
Functional organization Summary Functional_organization Functional organization is a type of organizational structure that uses the principle of specialization based on function or role. It allows decisions to be decentralized since issues are delegated to specialized persons or units, leaving them the responsibility of implementing, evaluating, or controlling the given procedures or goals.
Structural complexity (applied mathematics) Literature Structural_complexity_(applied_mathematics) > Literature ISBN 978-0-201-56717-5. OCLC 24374484. Nicolis, G (1989).
Born–Haber cycle Summary Born–Haber_cycle This lattice calculation is complex. To make gaseous ions from elements it is necessary to atomise the elements (turn each into gaseous atoms) and then to ionise the atoms. If the element is normally a molecule then we first have to consider its bond dissociation enthalpy (see also bond energy).
Column-oriented database Row-oriented systems Columnar_database > Description > Row-oriented systems If the index is heavily used, it can dramatically reduce the time for common operations. However, maintaining indexes adds overhead to the system, especially when new data is written to the database. Records not only need to be stored in the main table, but any attached indexes have to be updated as well.
On the coloured light of the binary stars and some other stars of the heavens Content On_the_coloured_light_of_the_binary_stars_and_some_other_stars_of_the_heavens > Content The same goes for sound and light. § 3 Doppler derives his equations for the frequency shift, in two cases: § 4 Doppler provides imaginary examples of large and small frequency shifts for sound: § 5 Doppler provides imaginary examples of large and small frequency shifts for light from stars. Velocities are expressed in Meilen/s, and the light speed has a rounded value of 42000 Meilen/s.
Noble gas compounds Fullerene adducts Noble_gas_compound > Fullerene adducts Noble gases can also form endohedral fullerene compounds where the noble gas atom is trapped inside a fullerene molecule. In 1993, it was discovered that when C60 is exposed to a pressure of around 3 bar of He or Ne, the complexes He@C60 and Ne@C60 are formed. Under these conditions, only about one out of every 650,000 C60 cages was doped with a helium atom; with higher pressures (3000 bar), it is possible to achieve a yield of up to 0.1%. Endohedral complexes with argon, krypton and xenon have also been obtained, as well as numerous adducts of He@C60.
Spreading resistance profiling Summary Spreading_resistance_profiling Spreading resistance profiling (SRP), also known as spreading resistance analysis (SRA), is a technique used to analyze resistivity versus depth in semiconductors. Semiconductor devices depend on the distribution of carriers (electrons or holes) within their structures to provide the desired performance. The carrier concentration (which can vary by up to ten orders of magnitude) can be inferred from the resistivity profile provided by SRP.
Power transmission Summary Power_transmission Power transmission is the movement of energy from its place of generation to a location where it is applied to perform useful work. Power is defined formally as units of energy per unit time. In SI units: watt = joule second = newton × meter second {\displaystyle {\text{watt}}={\frac {\text{joule}}{\text{second}}}={\frac {{\text{newton}}\times {\text{meter}}}{\text{second}}}} Since the development of technology, transmission and storage systems have been of immense interest to technologists and technology users.
Admissible heuristic Optimality proof Admissible_heuristic > Optimality proof As an example, let us say we have costs as follows:(the cost above/below a node is the heuristic, the cost at an edge is the actual cost) 0 10 0 100 0 START ---- O ----- GOAL \| \| 0\| \|100 \| \| O ------- O ------ O 100 1 100 1 100 So clearly we would start off visiting the top middle node, since the expected total cost, i.e. f ( n ) {\displaystyle f(n)} , is 10 + 0 = 10 {\displaystyle 10+0=10} . Then the goal would be a candidate, with f ( n ) {\displaystyle f(n)} equal to 10 + 100 + 0 = 110 {\displaystyle 10+100+0=110} . Then we would clearly pick the bottom nodes one after the other, followed by the updated goal, since they all have f ( n ) {\displaystyle f(n)} lower than the f ( n ) {\displaystyle f(n)} of the current goal, i.e. their f ( n ) {\displaystyle f(n)} is 100 , 101 , 102 , 102 {\displaystyle 100,101,102,102} .
Traffic light control and coordination Coordinated control Traffic_light_control_and_coordination > Types of control > Coordinated control A graphical representation of phase state on a two-axis plane of distance versus time clearly shows a "green band" that has been established based on signalized intersection spacing and expected vehicle speeds. In some countries (e.g. Germany, France and the Netherlands), this "green band" system is used to limit speeds in certain areas. Lights are timed in such a way that motorists can drive through without stopping if their speed is lower than a given limit, mostly 50 km/h (30 mph) in urban areas.
Renewable Energy Transition Drivers for current energy transition Green_transition > Drivers for current energy transition In non-electrified rural areas, the deployment of solar mini-grids can significantly improve electricity access. Employment opportunities by the green transition are associated with the use of renewable energy sources or building activity for infrastructure improvements and renovations. Additionally, the replacement of coal-based energy with renewables can lower the number of premature deaths caused by air pollution and reduce health costs.Governments ambition to attract international support for green growth initiatives and public demand for a clean environment have been found to be drivers of the energy transition in developing countries, such as Vietnam.
Traditional Ecological Knowledge Climate change Traditional_Ecological_Knowledge > Climate change The combination of the rise in temperatures and change in precipitation levels affects plant growth locations. The warming also affects insects and animals. The change in temperatures can affect many aspects from the times that insects emerge throughout the year to the changes in the habitats of animals throughout seasonal changes.As the temperature gets hotter, wild fires become more likely.
Structure (mathematical logic) Structures that are proper classes Interpretation_function > Other generalizations > Structures that are proper classes In the study of set theory and category theory, it is sometimes useful to consider structures in which the domain of discourse is a proper class instead of a set. These structures are sometimes called class models to distinguish them from the "set models" discussed above. When the domain is a proper class, each function and relation symbol may also be represented by a proper class. In Bertrand Russell's Principia Mathematica, structures were also allowed to have a proper class as their domain.
Hamiltonian (quantum mechanics) One particle Hamiltonian_(quantum_theory) > Schrödinger Hamiltonian > One particle By analogy with classical mechanics, the Hamiltonian is commonly expressed as the sum of operators corresponding to the kinetic and potential energies of a system in the form where is the potential energy operator and is the kinetic energy operator in which m {\displaystyle m} is the mass of the particle, the dot denotes the dot product of vectors, and is the momentum operator where a ∇ {\displaystyle \nabla } is the del operator. The dot product of ∇ {\displaystyle \nabla } with itself is the Laplacian ∇ 2 {\displaystyle \nabla ^{2}} . In three dimensions using Cartesian coordinates the Laplace operator is Although this is not the technical definition of the Hamiltonian in classical mechanics, it is the form it most commonly takes.
Bohr-Einstein debates Bohr's response Bohr-Einstein_debates > Post-revolution: First stage > Bohr's response This ambiguity would later come back in the form of what is still called today the measurement problem. However, Bohr in his article refuting the EPR paper, states “there is no question of a mechanical disturbance of the system under investigation.” Heisenberg quotes Bohr as saying, “I find all such assertions as ‘observation introduces uncertainty into the phenomenon’ inaccurate and misleading.” Manjit Kumar’s book on the Bohr-Einstein debates finds these assertions by Bohr contrary to his arguments. Others, such as the physicist Leon Rosenfeld, did find Bohr's argument convincing.
Veronika Hubeny Selected works Veronika_Hubeny > Selected works Horowitz, Gary T.; Hubeny, Veronika E. (2000). "Quasinormal modes of AdS black holes and the approach to thermal equilibrium". Physical Review D.
Gambling mathematics Standard deviation Gaming_mathematics > Expectation and strategy > Standard deviation The standard deviation for the even-money Roulette bet is one of the lowest out of all casinos games. Most games, particularly slots, have extremely high standard deviations. As the size of the potential payouts increase, so does the standard deviation.
Effects of fatigue on safety Factors Effects_of_fatigue_on_safety > Factors The Federal Motor Carrier Safety Administration identifies three main factors in driver fatigue: Circadian rhythm effects, sleep deprivation and cumulative fatigue effects, and industrial or "time-on-task" fatigue. Circadian rhythm effects describe the tendency for humans to experience a normal cycle in attentiveness and sleepiness through the 24-hour day. Those with a conventional sleep pattern (sleeping for seven or eight hours at night) experience periods of maximum fatigue in the early hours of the morning and a lesser period in the early afternoon. During the low points of this cycle, one experiences reduced attentiveness.
Structuralism In linguistics Structuralism > In linguistics a signifié '(signified'): the concept or meaning of the word.This differed from previous approaches that focused on the relationship between words and the things in the world that they designate.Although not fully developed by Saussure, other key notions in structural linguistics can be found in structural "idealism." A structural idealism is a class of linguistic units (lexemes, morphemes, or even constructions) that are possible in a certain position in a given syntagm, or linguistic environment (such as a given sentence). The different functional role of each of these members of the paradigm is called 'value' (French: valeur).
Maximum-likelihood estimation Discrete distribution, continuous parameter space Maximum_likelihood_principle > Examples > Discrete distribution, continuous parameter space The first term is 0 when p = 0. The second is 0 when p = 1. The third is zero when p = 49⁄80.

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