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Quantum chemist History Quantum_chemist > History However, prior to this a critical conceptual framework was provided by Gilbert N. Lewis in his 1916 paper The Atom and the Molecule, wherein Lewis developed the first working model of valence electrons. Important contributions were also made by Yoshikatsu Sugiura and S.C. Wang.
Demyelinating disease Epidemiology Demyelinating_disease > Epidemiology Incidence of demyelinating diseases varies by disorder. Some conditions, such as tabes dorsalis appear predominantly in males and begin in midlife. Optic neuritis, though, occurs preferentially in females typically between the ages of 30 and 35. Other conditions such as multiple sclerosis vary in prevalence depending on the country and population. This condition can appear in children and adults.
Steiner chain Properties under inversion Steiner's_porism > Properties under inversion Inversive properties of Steiner chains Circle inversion transforms one Steiner chain into another with the same number of circles. In the transformed chain, the tangent points between adjacent circles of the Steiner chain all lie on a circle, namely the concentric circle midway between the two fixed concentric circles. Since tangencies and circles are preserved under inversion, this property of all tangencies lying on a circle is also true in the original chain. This property is also shared with the Pappus chain of circles, which can be construed as a special limiting case of the Steiner chain.
Polluter pays principle Sweden Polluter_pays_principle > Applications in environmental law > Sweden The polluter pays principle is also known as extended producer responsibility (EPR). This is a concept that was probably first described by Thomas Lindhqvist for the Swedish government in 1990. EPR seeks to shift the responsibility of dealing with waste from governments (and thus, taxpayers and society at large) to the entities producing it. In effect, it internalised the cost of waste disposal into the cost of the product, theoretically meaning that the producers will improve the waste profile of their products, thus decreasing waste and increasing possibilities for reuse and recycling. The Organisation for Economic Co-operation and Development defines extended producer responsibility as: a concept where manufacturers and importers of products should bear a significant degree of responsibility for the environmental impacts of their products throughout the product life-cycle, including upstream impacts inherent in the selection of materials for the products, impacts from manufacturers’ production process itself, and downstream impacts from the use and disposal of the products. Producers accept their responsibility when designing their products to minimise life-cycle environmental impacts, and when accepting legal, physical or socio-economic responsibility for environmental impacts that cannot be eliminated by design.
Automated speech recognition 2000s Speech_recognition_technology > History > Practical speech recognition > 2000s Researchers have begun to use deep learning techniques for language modeling as well. In the long history of speech recognition, both shallow form and deep form (e.g. recurrent nets) of artificial neural networks had been explored for many years during 1980s, 1990s and a few years into the 2000s. But these methods never won over the non-uniform internal-handcrafting Gaussian mixture model/Hidden Markov model (GMM-HMM) technology based on generative models of speech trained discriminatively.
Halogen bonding History Halogen_bonding > History Through systematic and extensive microwave spectroscopy of gas-phase halogen bond adducts, Legon and coworkers drew attention to the similarities between halogen-bonding and better-known hydrogen-bonding interactions.In 2007, computational calculations by Politzer and Murray showed that an anisotropic electron density distribution around the halogen nucleus — the "σ-hole" — underlay the high directionality of the halogen bond. This hole was then experimentally observed using Kelvin probe force microscopy.In 2020, Kellett et al. showed that halogen bonds also have a π-covalent character similar to metal coordination bonds. In August 2023 the "π-hole" was too experimentally observed
Complex matrix Physics references Complex_matrix > References > Physics references (1968), Quantum Mechanics (3rd ed. ), McGraw–Hill Weinberg, Steven (1995), The Quantum Theory of Fields. Volume I: Foundations, Cambridge University Press, ISBN 0-521-55001-7 Wherrett, Brian S. (1987), Group Theory for Atoms, Molecules and Solids, Prentice–Hall International, ISBN 0-13-365461-3 Zabrodin, Anton; Brezin, Édouard; Kazakov, Vladimir; Serban, Didina; Wiegmann, Paul (2006), Applications of Random Matrices in Physics (NATO Science Series II: Mathematics, Physics and Chemistry), Berlin, DE; New York, NY: Springer-Verlag, ISBN 978-1-4020-4530-1
Aquo ligand Binuclear-aquo complexes Aquo_ligand > Stoichiometry and structure > Binuclear-aquo complexes In the binuclear ion 4+ each bridging water molecule donates one pair of electrons to one cobalt ion and another pair to the other cobalt ion. The Co-O (bridging) bond lengths are 213 picometers, and the Co-O (terminal) bond lengths are 10 pm shorter.The complexes 4+ and 4+ contain metal-metal bonds.
Thermoelectric battery Summary Thermoelectric_battery A thermoelectric battery stores energy when charged by converting heat into chemical energy and produces electricity when discharged. Such systems potentially offer an alternative means of disposing of waste heat from plants that burn fossil fuels and/or nuclear energy.
Statistical modeling General remarks Statistical_Model > General remarks Relatedly, the statistician Sir David Cox has said, "How translation from subject-matter problem to statistical model is done is often the most critical part of an analysis".There are three purposes for a statistical model, according to Konishi & Kitagawa. Predictions Extraction of information Description of stochastic structuresThose three purposes are essentially the same as the three purposes indicated by Friendly & Meyer: prediction, estimation, description. The three purposes correspond with the three kinds of logical reasoning: deductive reasoning, inductive reasoning, abductive reasoning.
Reactivity–selectivity principle Summary Reactivity-selectivity_principle When reactivity-selectivity relationships do exist they signify different reaction modes. In one study the reactivity of two different free radical species (A, sulfur, B carbon) towards addition to simple alkenes such as acrylonitrile, vinyl acetate and acrylamide was examined. The sulfur radical was found to be more reactive (6*108 vs. 1*107 M−1.s−1) and less selective (selectivity ratio 76 vs 1200) than the carbon radical.
Scaling of innovations Tools Scaling_of_innovations > Tools Most recently, the International Maize and Wheat Improvement Center (CIMMYT) and the PPPLab developed the Scaling Scan. All these frameworks assign the difficulty of scaling innovations to a lack of clarity about what is required to achieve sustained results beyond smaller pilot programs. The tools help simplify and explain the complexities of scaling and guide users to systematically think through key elements, ingredients, or success factors. == References ==
The Turing Guide Contents The_Turing_Guide > Contents The Turing Guide is divided into eight main parts, covering various aspects of Alan Turing's life and work: Biography: Biographical aspects of Alan Turing. The Universal Machine and Beyond: Turing's universal machine (now known as a Turing machine), developed while at King's College, Cambridge, which provides a theoretical framework for reasoning about computation, a starting point for the field of theoretical computer science. Codebreaker: Turing's work on codebreaking during World War II at Bletchley Park, especially the Bombe for decrypting the German Enigma machine. Computers after the War: Turing's post-War work on computing, at the National Physical Laboratory (NPL) and at the University of Manchester.
Inverse function theorem Summary Inverse_function_theorem In mathematics, specifically differential calculus, the inverse function theorem gives a sufficient condition for a function to be invertible in a neighborhood of a point in its domain: namely, that its derivative is continuous and non-zero at the point. The theorem also gives a formula for the derivative of the inverse function. In multivariable calculus, this theorem can be generalized to any continuously differentiable, vector-valued function whose Jacobian determinant is nonzero at a point in its domain, giving a formula for the Jacobian matrix of the inverse. There are also versions of the inverse function theorem for complex holomorphic functions, for differentiable maps between manifolds, for differentiable functions between Banach spaces, and so forth. The theorem was first established by Picard and Goursat using an iterative scheme: the basic idea is to prove a fixed point theorem using the contraction mapping theorem.
Cheyne–Stokes respiration Summary Cheyne–Stokes_respiration The distinction lies in what is observed at the trough of ventilation: Cheyne–Stokes respiration involves apnea (since apnea is a prominent feature in their original description) while periodic breathing involves hypopnea (abnormally small but not absent breaths). These phenomena can occur during wakefulness or during sleep, where they are called the central sleep apnea syndrome (CSAS).It may be caused by damage to respiratory centers, or by physiological abnormalities in congestive heart failure, and is also seen in newborns with immature respiratory systems and in visitors new to high altitudes. One example is the breathing pattern in Joubert syndrome and related disorders.
Data mining Summary Data_mining The actual data mining task is the semi-automatic or automatic analysis of large quantities of data to extract previously unknown, interesting patterns such as groups of data records (cluster analysis), unusual records (anomaly detection), and dependencies (association rule mining, sequential pattern mining). This usually involves using database techniques such as spatial indices. These patterns can then be seen as a kind of summary of the input data, and may be used in further analysis or, for example, in machine learning and predictive analytics.
Spectral music Summary Spectral_music Spectral music uses the acoustic properties of sound – or sound spectra – as a basis for composition.
Human somatic variation Somatic cancer-associated mutations in normal tissues Human_somatic_variation > Somatic cancer-associated mutations in normal tissues The main reasons are the generally slower replicative index, clonally restrictive tissue architecture, difficulty of tissue access, and low frequency of mutation occurrence. Recently, the analysis of somatic mutations in benign tissues adjacent to tumors revealed that 80% of samples harbors clonal mutations, with increased frequency associated with older age, smoking, and concurrent mutations in DNA repair genes. With the advent of NGS, it has become increasingly clear that somatic mutations accumulate with aging in normal tissue, even in individuals who are cancer-free.This suggested that clonal expansions driven by cancer genes are a near-universal feature of aging. NGS technologies revealed that the clonal expansions of cancer-associated mutations are very common condition in somatic tissues.
Chromatin Methods to investigate chromatin Chromatin_structure > Methods to investigate chromatin DNA footprinting is a method aimed at identifying protein-bound DNA. It uses labeling and fragmentation coupled to gel electrophoresis to identify areas of the genome that have been bound by proteins. MNase-seq (Micrococcal Nuclease sequencing) uses the micrococcal nuclease enzyme to identify nucleosome positioning throughout the genome. Chromosome conformation capture determines the spatial organization of chromatin in the nucleus, by inferring genomic locations that physically interact. MACC profiling (Micrococcal nuclease ACCessibility profiling) uses titration series of chromatin digests with micrococcal nuclease to identify chromatin accessibility as well as to map nucleosomes and non-histone DNA-binding proteins in both open and closed regions of the genome.
Amino acid metabolism Exopeptidases Protein_metabolism > Protein breakdown > Protein catabolism via enzymes > Proteases > Exopeptidases Exopeptidases are enzymes that can cleave the end of an amino acid side chain mostly through the addition of water. Exopeptidase enzymes exist in the small intestine. These enzymes have two classes: aminopeptidases are a brush border enzyme and carboxypeptidases which is from the pancreas.
Language-based system Examples Language-based_system > Examples Burroughs MCP Cosmos Emerald Inferno JX Lisp machine Midori Oberon Singularity Smalltalk Theseus OS UCSD P-system Verve
Biogeomorphology Research approaches Biogeomorphology > Research approaches There are two approaches to research in biogeomorphology. One is through the statistical and empirically derived means. This is an approach commonly used in the fields of ecology and biology. The approach is simply to employ large replication studies and deriving patterns from statistical data. Whereas taking a more geomorphic research approach tends to derive patterns via theoretic knowledge and detailed measurements of multiple factors. In turn, this uses smaller sample sizes than that of large replication studies.
Uniform acceleration Instantaneous acceleration Radial_acceleration > Definition and properties > Instantaneous acceleration Instantaneous acceleration, meanwhile, is the limit of the average acceleration over an infinitesimal interval of time. In the terms of calculus, instantaneous acceleration is the derivative of the velocity vector with respect to time: As acceleration is defined as the derivative of velocity, v, with respect to time t and velocity is defined as the derivative of position, x, with respect to time, acceleration can be thought of as the second derivative of x with respect to t: (Here and elsewhere, if motion is in a straight line, vector quantities can be substituted by scalars in the equations.) By the fundamental theorem of calculus, it can be seen that the integral of the acceleration function a(t) is the velocity function v(t); that is, the area under the curve of an acceleration vs. time (a vs. t) graph corresponds to the change of velocity. Likewise, the integral of the jerk function j(t), the derivative of the acceleration function, can be used to find the change of acceleration at a certain time:
Nicolas Léonard Sadi Carnot Carnot cycle Nicolas_Léonard_Sadi_Carnot > Reflections on the Motive Power of Fire > Carnot cycle Carnot concludes further that the choice of the working fluid, its density or the volume occupied by it cannot change this maximum efficiency. Using the equivalence of any working gas used in heat engines, he deduced that the difference in the specific heat of a gas measured at constant pressure and at constant volume must be constant for all gases. By comparing the operation of his hypothetical heat-engines for two different volumes occupied by the same amount of working gas he correctly deduces the relation between entropy and volume for an isothermal process: Δ S ∝ ln ⁡ V V 0 . {\displaystyle \Delta S\propto \ln {\frac {V}{V_{0}}}.}
Product finder Technical implementation Product_finder > Technical implementation Unlike hierarchical tables such as menu trees, relational database tables can have rows that are linked to rows in other tables by a keyword that they may share. The relationships between these tables can take several forms: one-to-one, one-to-many or many-to-many. Databases like these make it simple for product finders to discover the relationships between keywords that consumer uses. This information helps these systems predict what consumers will be interesting in purchasing so the software can guide customers to their ideal product and encourage a sale.
Gating signal Summary Gating_signal 2. Audio processing: In audio applications, signal gating is used to reduce background noise or eliminate unwanted sounds.
Mechanics' institute Origins and history Mechanics'_institute > Origins and history Some mechanics' institutes also offered a programme from the arts; Wisbech Mechanics' institute booked Mrs Butler to give readings from Shakespeare's plays and Milton's Paradise Lost to audiences of nearly a thousand.G. Jefferson explains: The first phase, the Mechanics Institute movement, grew in an atmosphere of interest by a greater proportion of the population in scientific matters revealed in the public lectures of famous scientists such as Faraday. More precisely, as a consequence of the introduction of machinery a class workmen emerged to build, maintain and repair, the machines on which the blessing of progress depended, at a time when population shifts and the dissolving influences of industrialization in the new urban areas, where these were concentrated, destroyed the inadequate old apprentice system and threw into relief the connection between material advancement and the necessity of education to take part in its advantages.
History of electric power transmission Power electronics History_of_electric_power_transmission > Power electronics Power electronics is the application of solid-state electronics to the control and conversion of electric power. Power electronics started with the development of the mercury arc rectifier. Invented by Peter Cooper Hewitt in 1902, it was used to convert alternating current (AC) into direct current (DC).
Rb gene Regulation of metabolism Rb_gene > Non-canonical roles > Regulation of metabolism pRb has also been implicated in regulating metabolism through interactions with components of cellular metabolic pathways. RB1 mutations can cause alterations in metabolism, including reduced mitochondrial respiration, reduced activity in the electron transport chain, and changes in flux of glucose and/or glutamine. Particular forms of pRb have been found to localize to the outer mitochondrial membrane and directly interacts with Bax to promote apoptosis.
Labile hypertension Types Labile_hypertension > Types Some of the physical symptoms that accompany include headache, weakness and fear. Paroxysmal hypertension is different from panic disorder in which they are characterised with extreme elevation of blood pressure that is not triggered by fear. In panic disorder, elevation of blood pressure is generally mild and is normally triggered by fear or panic. There is a small percentage, approximately 2% who raises suspicion for have pheochromocytoma, a tumour in the adrenal glands. This involves the sympathetic nervous system and treatment for paroxysmal hypertension is available.
Natural Evolution Strategy Natural gradient ascent Natural_Evolution_Strategy > Method > Natural gradient ascent Instead of using the plain stochastic gradient for updates, NES follows the natural gradient, which has been shown to possess numerous advantages over the plain (vanilla) gradient, e.g.: the gradient direction is independent of the parameterization of the search distribution the updates magnitudes are automatically adjusted based on uncertainty, in turn speeding convergence on plateaus and ridges.The NES update is therefore θ ← θ + η F − 1 ∇ θ J ( θ ) {\displaystyle \theta \leftarrow \theta +\eta \mathbf {F} ^{-1}\nabla _{\theta }J(\theta )} ,where F {\displaystyle \mathbf {F} } is the Fisher information matrix. The Fisher matrix can sometimes be computed exactly, otherwise it is estimated from samples, reusing the log-derivatives ∇ θ log ⁡ π ( x | θ ) {\displaystyle \nabla _{\theta }\log \pi (x|\theta )} .
Flyback transformer Operation and usage Flyback_transformer > Operation and usage The earliest sets used a shunt vacuum tube regulator, but the introduction of solid-state sets employed a simpler voltage-dependent resistor. The rectified voltage is then used to supply the final anode of the cathode ray tube. There are often auxiliary windings that produce lower voltages for driving other parts of the television circuitry. The voltage used to bias the varactor diodes in modern tuners is often derived from the flyback transformer ("Line OutPut Transformer" LOPT). In tube sets, a one or two-turn filament winding is located on the opposite side of the core as the HV secondary, used to drive the HV rectifier tube's heater.
Graph rewriting Implementations and applications Graph_rewriting_system > Implementations and applications It saves graphs and graph grammar rules as XML files and is written in C#. Soley Studio, is an integrated development environment for graph transformation systems.
Class (set theory) Examples Proper_class > Examples The collection of all algebraic structures of a given type will usually be a proper class. Examples include the class of all groups, the class of all vector spaces, and many others. In category theory, a category whose collection of objects forms a proper class (or whose collection of morphisms forms a proper class) is called a large category. The surreal numbers are a proper class of objects that have the properties of a field.
Glycolysis History Glucose_oxidation_reaction > History Buchner demonstrated that the conversion of glucose to ethanol was possible using a non-living extract of yeast, due to the action of enzymes in the extract. : 135–148 This experiment not only revolutionized biochemistry, but also allowed later scientists to analyze this pathway in a more controlled laboratory setting. In a series of experiments (1905-1911), scientists Arthur Harden and William Young discovered more pieces of glycolysis.
Mir-133 microRNA precursor family Summary Mir-133_microRNA_precursor_family mir-133 is a type of non-coding RNA called a microRNA that was first experimentally characterised in mice. Homologues have since been discovered in several other species including invertebrates such as the fruitfly Drosophila melanogaster. Each species often encodes multiple microRNAs with identical or similar mature sequence. For example, in the human genome there are three known miR-133 genes: miR-133a-1, miR-133a-2 and miR-133b found on chromosomes 18, 20 and 6 respectively. The mature sequence is excised from the 3' arm of the hairpin. miR-133 is expressed in muscle tissue and appears to repress the expression of non-muscle genes.
Neural computing Reinforcement learning Artificial_Neural_Networks > Models > Learning paradigms > Reinforcement learning , a m ∈ A {\displaystyle \textstyle {a_{1},...,a_{m}}\in A} . Because the state transitions are not known, probability distributions are used instead: the instantaneous cost distribution P ( c t | s t ) {\displaystyle \textstyle P(c_{t}|s_{t})} , the observation distribution P ( x t | s t ) {\displaystyle \textstyle P(x_{t}|s_{t})} and the transition distribution P ( s t + 1 | s t , a t ) {\displaystyle \textstyle P(s_{t+1}|s_{t},a_{t})} , while a policy is defined as the conditional distribution over actions given the observations. Taken together, the two define a Markov chain (MC).
Bone marrow toxicity Research Bone_marrow_toxicity > Research In developing new chemotherapeutics, the efficacy of the drug against the disease is often balanced against the likely level of myelotoxicity the drug will cause. In-vitro colony forming cell (CFC) assays using normal human bone marrow grown in appropriate semi-solid media such as ColonyGEL have been shown to be useful in predicting the level of clinical myelotoxicity a certain compound might cause if administered to humans. These predictive in-vitro assays reveal effects the administered compounds have on the bone marrow progenitor cells that produce the various mature cells in the blood and can be used to test the effects of single drugs or the effects of drugs administered in combination with others.
Reversible cellular automaton Theory Reversible_cellular_automaton > Theory The time-reversed dynamics of the automaton can be described by another cellular automaton. Clearly, for this to be possible, the update rule must be bijective. In the other direction, if the update rule is bijective, then it has an inverse function that is also bijective.
Switching power Summary Switching_power In computer architecture, dynamic voltage scaling is a power management technique in which the voltage used in a component is increased or decreased, depending upon circumstances. Dynamic voltage scaling to increase voltage is known as overvolting; dynamic voltage scaling to decrease voltage is known as undervolting. Undervolting is done in order to conserve power, particularly in laptops and other mobile devices, where energy comes from a battery and thus is limited, or in rare cases, to increase reliability. Overvolting is done in order to support higher frequencies for performance. The term "overvolting" is also used to refer to increasing static operating voltage of computer components to allow operation at higher speed (overclocking).
Smoothed Particle Hydrodynamics Software Smoothed_Particle_Hydrodynamics > External links > Software Algodoo is a 2D simulation framework for education using SPH AQUAgpusph is the free (GPLv3) SPH of the researchers, by the researchers, for the researchers dive solutions is a commercial web-based SPH engineering software for CFD purposes DualSPHysics is a mostly open source SPH code based on SPHysics and using GPU computing. The open source components are available under the LGPL. FLUIDS v.1 is a simple, open source (Zlib), real-time 3D SPH implementation in C++ for liquids for CPU and GPU. Fluidix is a GPU-based particle simulation API available from OneZero Software GADGET is a freely available (GPL) code for cosmological N-body/SPH simulations GPUSPH SPH simulator with viscosity (GPLv3) Pasimodo is a program package for particle-based simulation methods, e.g. SPH LAMMPS is a massively parallel, open-source classical molecular dynamics code that can perform SPH simulations Physics Abstraction Layer is an open source abstraction system that supports real time physics engines with SPH support PreonLab is a commercial engineering software developed by FIFTY2 Technology implementing an implicit SPH method Punto is a freely available visualisation tool for particle simulations pysph Open Source Framework for Smoothed Particle Hydrodynamics in Python (New BSD License) Py-SPHViewer Open Source python visualisation tool for Smoothed Particle Hydrodynamics simulations.
X-Ray Engine Setting X-Ray_Engine > Setting In keeping with the post-nuclear decay within the Zone, extreme radiation has caused mutations among animals and plants in the area. As a result of the second disaster, the Zone is also littered with dangerous small areas of altered physics, known as anomalies. Explorers and scavengers operating within the Zone, known as Stalkers, possess an anomaly detector, which emits warning beeps of a varying frequency depending on their proximity to an anomaly.
Biochemical pathway Overview Molecular_pathway > Overview In times of excess lipid or protein energy sources, certain reactions in the glycolysis pathway may run in reverse to produce glucose 6-phosphate, which is then used for storage as glycogen or starch.Metabolic pathways are often regulated by feedback inhibition. Some metabolic pathways flow in a 'cycle' wherein each component of the cycle is a substrate for the subsequent reaction in the cycle, such as in the Krebs Cycle (see below). Anabolic and catabolic pathways in eukaryotes often occur independently of each other, separated either physically by compartmentalization within organelles or separated biochemically by the requirement of different enzymes and co-factors.
Robust Security Network Key hierarchy Pairwise_Master_Key > Key hierarchy RSNA defines two key hierarchies: Pairwise key hierarchy, to protect unicast traffic GTK, a hierarchy consisting of a single key to protect multicast and broadcast trafficThe description of the key hierarchies uses the following two functions: L(Str, F, L) - From Str starting from the left, extract bits F through F+L–1. PRF-n - Pseudo-random function producing n bits of output, there are the 128, 192, 256, 384 and 512 versions, each of these output these number of bits.The pairwise key hierarchy utilizes PRF-384 or PRF-512 to derive session-specific keys from a PMK, generating a PTK, which gets partitioned into a KCK and a KEK plus all the temporal keys used by the MAC to protect unicast communication. The GTK shall be a random number which also gets generated by using PRF-n, usually PRF-128 or PRF-256, in this model, the group key hierarchy takes a GMK (Group Master Key) and generates a GTK.
Credit information Switzerland Personal_data > Laws and standards > Switzerland The Federal Act on Data Protection of 19 June 1992 (in force since 1993) has set up a protection of privacy by prohibiting virtually any processing of personal data which is not expressly authorized by the data subjects. The protection is subject to the authority of the Federal Data Protection and Information Commissioner.Additionally, any person may ask in writing a company (managing data files) the correction or deletion of any personal data. The company must respond within thirty days.
Bolo punch Summary Bolo_punch and Joe Calzaghe also use the bolo punch frequently. When used in boxing, the bolo punch's range of motion is like that of a hook combined with an uppercut. As such, the punch should be thrown at 4–5 o'clock from an orthodox boxer's perspective.
Metric power Examples and uses Metric_power > Examples and uses : 6 On their website, Apple states that data collected from their devices in conjunction with specific apps (for example, health apps) is used to "promote healthier habits. "Workplaces have also been known to take advantage of metric power in forms of "surveillance, electronic performance monitoring, personal analytics, wearable self- and other-tracking and monitoring. ": 1785 Beer understands call-centres as a prime example of workplace metric power.
Left invariant Abelian Lie groups Lie_correspondence > Abelian Lie groups Let G be a connected Lie group. Since the Lie algebra of the center of G is the center of the Lie algebra of G (cf. the previous §), G is abelian if and only if its Lie algebra is abelian. If G is abelian, then the exponential map exp: g → G {\displaystyle \exp :{\mathfrak {g}}\to G} is a surjective group homomorphism. The kernel of it is a discrete group (since the dimension is zero) called the integer lattice of G and is denoted by Γ {\displaystyle \Gamma } .
Topological fluid dynamics Summary Topological_fluid_dynamics A mathematical introduction to this subject is given by Arnold & Khesin (1998) and recent survey articles and contributions may be found in Ricca (2009), and Moffatt, Bajer & Kimura (2013). Topology is also crucial to the structure of neutral surfaces in a fluid (such as the ocean) where the equation of state nonlinearly depends on multiple components (e.g. salinity and heat). Fluid parcels remain neutrally buoyant as they move along neutral surfaces, despite variations in salinity or heat. On such surfaces, the salinity and heat are functionally related, but this function is multivalued. The spatial regions within which this function becomes single-valued are those where there is at most one contour of salinity (or heat) per isovalue, which are precisely the regions associated with each edge of the Reeb graph of the salinity (or heat) on the surface (Stanley 2019).
Bivector Maxwell's equations Oriented_plane_segment > Four dimensions > Maxwell's equations For general quantity M they act as grade lowering and raising differential operators. In particular if M is a scalar then this operator is just the gradient, and it can be thought of as a geometric algebraic del operator.
Spontaneous emission Theory Spontaneous_emission > Theory The quantum field theory of electrons and electromagnetic fields is known as quantum electrodynamics. In quantum electrodynamics (or QED), the electromagnetic field has a ground state, the QED vacuum, which can mix with the excited stationary states of the atom. As a result of this interaction, the "stationary state" of the atom is no longer a true eigenstate of the combined system of the atom plus electromagnetic field.
History of the International System of Units Unit names History_of_the_International_System_of_Units > Lexicographic conventions > Unit names : 148 The English spelling and even names for certain SI units and metric prefixes depend on the variety of English used. US English uses the spelling deka-, meter, and liter, whilst International English uses deca-, metre, and litre. The name of the unit whose symbol is t and which is defined according to 1 t = 103 kg is 'metric ton' in US English and 'tonne' in International English. : iii
Distributed database management system Classification Data_base > Classification Shared-nothing architecture, where each processing unit has its own main memory and other storage.Probabilistic databases employ fuzzy logic to draw inferences from imprecise data. Real-time databases process transactions fast enough for the result to come back and be acted on right away. A spatial database can store the data with multidimensional features.
Coalescing (computer science) Summary Coalescing_(computer_science) Coalescing alleviates this issue by setting the neighboring blocks of freed memory to be contiguous without boundaries, such that part or all of it can be allocated for the request. Among other techniques, coalescing is used to reduce external fragmentation, but is not totally effective. Coalescing can be done as soon as blocks are freed, or it can be deferred until some time later (known as deferred coalescing), or it might not be done at all. Coalescence and related techniques like heap compaction, can be used in garbage collection.
Cell (journal) Editors Cell_(journal) > Editors John Pham, 2018–present Emilie Marcus, 2003–2017 Vivian Siegel, 1999–2003 Benjamin Lewin, 1974–1999
Java collections framework Differences from Arrays Collections_API > Differences from Arrays Collections and arrays are similar in that they both hold references to objects and they can be managed as a group. However, unlike arrays, Collections do not need to be assigned a certain capacity when instantiated. Collections can grow and shrink in size automatically when objects are added or removed.
Biological Safety In synthetic biology Biosafety > In synthetic biology A complete understanding of experimental risks associated with synthetic biology is helping to enforce the knowledge and effectiveness of biosafety. With the potential future creation of man-made unicellular organisms, some are beginning to consider the effect that these organisms will have on biomass already present. Scientists estimate that within the next few decades, organism design will be sophisticated enough to accomplish tasks such as creating biofuels and lowering the levels of harmful substances in the atmosphere. Scientist that favor the development of synthetic biology claim that the use of biosafety mechanisms such as suicide genes and nutrient dependencies will ensure the organisms cannot survive outside of the lab setting in which they were originally created.
Internet Assigned Numbers Authority IP addresses Internet_Assigned_Numbers_Authority > Responsibilities > IP addresses IANA delegates allocations of IP address blocks to regional Internet registries (RIRs). Each RIR allocates addresses for a different area of the world. Collectively the RIRs have created the Number Resource Organization formed as a body to represent their collective interests and ensure that policy statements are coordinated globally.The RIRs divide their allocated address pools into smaller blocks and delegate them to Internet service providers and other organizations in their operating regions. Since the introduction of the CIDR system, IANA has typically allocated address space in the size of /8 prefix blocks for IPv4 and/23 to/12 prefix blocks from the 2000::/3 IPv6 block to requesting regional registries as needed. Since the exhaustion of the Internet Protocol Version 4 address space, no further IPv4 address space is allocated by IANA.
P53 upregulated modulator of apoptosis Side-effect treatment P53_upregulated_modulator_of_apoptosis > Cancer therapeutics > Side-effect treatment Irradiation therapy is dose-limited by undesired side effects in healthy tissue. PUMA has been shown to be active in inducing apoptosis in hematopoietic and intestinal tissue following γ-irradiation. Since inhibition of PUMA does not directly cause spontaneous malignancies, therapeutics to inhibit PUMA function in healthy tissue could lessen or eliminate the side effects of traditional cancer therapies.
Free chlorine Equilibria and stability of solutions NaClO > Chemistry > Equilibria and stability of solutions At pH below 2, the majority of the chlorine in the solution is in the form of dissolved elemental Cl2. At pH greater than 7.4, the majority is in the form of hypochlorite ClO−. The equilibrium can be shifted by adding acids (such as hydrochloric acid) or bases (such as sodium hydroxide) to the solution: ClO− (aq) + 2 HCl (aq) → Cl2 (g) + H2O (aq) + Cl− (aq) Cl2 (g) + 2 OH− → ClO− (aq) + Cl− (aq) + H2O (aq)At a pH of about 4, such as obtained by the addition of strong acids like hydrochloric acid, the amount of undissociated (nonionized) HOCl is highest.
Domain name registry Summary Domain_name_registration A domain name registry is a database of all domain names and the associated registrant information in the top level domains of the Domain Name System (DNS) of the Internet that enables third party entities to request administrative control of a domain name. Most registries operate on the top-level and second-level of the DNS. A registry operator, sometimes called a network information center (NIC), maintains all administrative data of the domain and generates a zone file which contains the addresses of the nameservers for each domain. Each registry is an organization that manages the registration of domain names within the domains for which it is responsible, controls the policies of domain name allocation, and technically operates its domain.
Ball tree Construction Ball_tree > Construction A number of ball tree construction algorithms are available. The goal of such an algorithm is to produce a tree that will efficiently support queries of the desired type (e.g. nearest-neighbor) in the average case. The specific criteria of an ideal tree will depend on the type of question being answered and the distribution of the underlying data. However, a generally applicable measure of an efficient tree is one that minimizes the total volume of its internal nodes.
Hydrodynamica Summary Hydrodynamica Hydrodynamica (Latin for Hydrodynamics) is a book published by Daniel Bernoulli in 1738. The title of this book eventually christened the field of fluid mechanics as hydrodynamics. The book deals with fluid mechanics and is organized around the idea of conservation of energy, as received from Christiaan Huygens's formulation of this principle. The book describes the theory of water flowing through a tube and of water flowing from a hole in a container.
Respirometry Summary Respirometry Respirometry is a general term that encompasses a number of techniques for obtaining estimates of the rates of metabolism of vertebrates, invertebrates, plants, tissues, cells, or microorganisms via an indirect measure of heat production (calorimetry).
Sensitivity (control systems) Sensitivity function as a measure of disturbance attenuation Sensitivity_(control_systems) > Sensitivity function > Sensitivity function as a measure of disturbance attenuation The sensitivity function also describes the transfer function from external disturbance to process output. In fact, assuming an additive disturbance n after the output of the plant, the transfer functions of the closed loop system are given by Y ( s ) = C ( s ) G ( s ) 1 + C ( s ) G ( s ) R ( s ) + 1 1 + C ( s ) G ( s ) N ( s ) . {\displaystyle Y(s)={\frac {C(s)G(s)}{1+C(s)G(s)}}R(s)+{\frac {1}{1+C(s)G(s)}}N(s).}
Chronic wasting disease Spread Chronic_wasting_disease > Cause > Spread Researchers in July 2019 stated that "with all the research on the malignity of prions, and the permanence of prions in the wider environment, and their resistance to destruction and degradation, it is necessary to reduce the potential sources of exposure to CWD." In fact an APHIS scientist observed that, while the longevity of CWD prion is unknown, the scrapie prion has been measured to endure for 16 years. The PrPCWD protein is insoluble in all but the strongest solvents, and highly resistant to digestion by proteases. PrPCWD converts the normal protein PrPC into more of itself upon contact, and binds together forming aggregates.
K-regular sequence Automata-theoretic K-regular_sequence > Definition > Automata-theoretic The formal series definition of a k-regular sequence leads to an automaton characterization similar to Schützenberger's matrix machine.
Intel i860 Technical features Intel_i860 > Technical features But the "floating-point or graphics" instructions use a register file that can be accessed by the floating point units as either thirty-two 32-bit, sixteen 64-bit, or eight 128-bit floating-point registers, or that can be accessed by the graphics unit as sixteen 64-bit integer registers. The "core" unit is responsible for fetching instructions, and in the normal "single-instruction" mode can fetch one 32-bit "core" or one 32-bit "floating point or graphics" instruction per cycle. But when executing in dual-instruction mode, the instruction cache is accessed as VLIW instructions consisting of a 32-bit "core" instruction paired with a 32-bit "floating-point or graphics" instruction, simultaneously fetched together over a 64-bit bus.Intel referred to the design as the "i860 64-Bit Microprocessor".Intel i860 instructions acted on data sizes from 8-bit through 128-bit.The graphics supports SIMD-like instructions in addition to basic 64-bit integer math.
DC to DC converter Summary DC–DC_converter A DC-to-DC converter is an electronic circuit or electromechanical device that converts a source of direct current (DC) from one voltage level to another. It is a type of electric power converter. Power levels range from very low (small batteries) to very high (high-voltage power transmission).
Antagonistic pleiotropy hypothesis Telomere Theory Antagonistic_pleiotropy_hypothesis > Potential Examples > DNA repair > Telomere Theory Another example related to aging is the Telomere theory. Telomere theory proposes that telomeres shorten with repeated cell division which attribute to cell senescence and tissue damage. The end replication problem explains the mechanism behind the inability of DNA polymerase to commence the RNA primer to perform its function in completing the lagging strand due to the shortening of DNA. Telomere shortening is common in somatic cells.
Diabetes mellitus Blood pressure lowering Diabetes > Management > Medications > Blood pressure lowering Cardiovascular disease is a serious complication associated with diabetes, and many international guidelines recommend blood pressure treatment targets that are lower than 140/90 mmHg for people with diabetes. However, there is only limited evidence regarding what the lower targets should be. A 2016 systematic review found potential harm to treating to targets lower than 140 mmHg, and a subsequent systematic review in 2019 found no evidence of additional benefit from blood pressure lowering to between 130 – 140mmHg, although there was an increased risk of adverse events.2015 American Diabetes Association recommendations are that people with diabetes and albuminuria should receive an inhibitor of the renin-angiotensin system to reduce the risks of progression to end-stage renal disease, cardiovascular events, and death. There is some evidence that angiotensin converting enzyme inhibitors (ACEIs) are superior to other inhibitors of the renin-angiotensin system such as angiotensin receptor blockers (ARBs), or aliskiren in preventing cardiovascular disease. Although a more recent review found similar effects of ACEIs and ARBs on major cardiovascular and renal outcomes. There is no evidence that combining ACEIs and ARBs provides additional benefits.
Pyruvate kinase Isozymes in vertebrates Pyruvate_kinase > Isozymes in vertebrates The R-state, characterized by high substrate affinity, serves as the activated form of pyruvate kinase and is stabilized by PEP and fructose 1,6-bisphosphate (FBP), promoting the glycolytic pathway. The T-state, characterized by low substrate affinity, serves as the inactivated form of pyruvate kinase, bound and stabilized by ATP and alanine, causing phosphorylation of pyruvate kinase and the inhibition of glycolysis. The M2 isozyme of pyruvate kinase can form tetramers or dimers.
Medical diagnosis Medical uses Medical_diagnosis > Medical uses A complaint expressed by a patient. The fact that a patient has sought a diagnostician can itself be an indication to perform a diagnostic procedure. For example, in a doctor's visit, the physician may already start performing a diagnostic procedure by watching the gait of the patient from the waiting room to the doctor's office even before she or he has started to present any complaints.Even during an already ongoing diagnostic procedure, there can be an indication to perform another, separate, diagnostic procedure for another, potentially concomitant, disease or condition. This may occur as a result of an incidental finding of a sign unrelated to the parameter of interest, such as can occur in comprehensive tests such as radiological studies like magnetic resonance imaging or blood test panels that also include blood tests that are not relevant for the ongoing diagnosis.
Hydrogen isotope biogeochemistry Kinetic and equilibrium isotope effects Hydrogen_isotope_biogeochemistry > Physical chemistry > Kinetic and equilibrium isotope effects This effect is especially prevalent in hydrogen isotopes, since addition of a neutron doubles the mass from protium to deuterium. For higher order elements like carbon, oxygen, nitrogen, or sulfur, the mass difference is diluted. Physical chemists often model bonding with the quantum harmonic oscillator, simplifying a hydrogen-hydrogen bond as two balls connected by a spring.
Axiom of substitution Applications Axiom_of_collection > Applications The axiom schema of replacement is not necessary for the proofs of most theorems of ordinary mathematics. Indeed, Zermelo set theory (Z) already can interpret second-order arithmetic and much of type theory in finite types, which in turn are sufficient to formalize the bulk of mathematics. Although the axiom schema of replacement is a standard axiom in set theory today, it is often omitted from systems of type theory and foundation systems in topos theory. At any rate, the axiom schema drastically increases the strength of ZF, both in terms of the theorems it can prove - for example the sets shown to exist - and also in terms of its proof-theoretic consistency strength, compared to Z. Some important examples follow: Using the modern definition due to von Neumann, proving the existence of any limit ordinal greater than ω requires the replacement axiom.
Bijective Function Properties Partial_bijection > Properties If X and Y are finite sets with the same cardinality, and f: X → Y, then the following are equivalent: f is a bijection. f is a surjection. f is an injection. For a finite set S, there is a bijection between the set of possible total orderings of the elements and the set of bijections from S to S. That is to say, the number of permutations of elements of S is the same as the number of total orderings of that set—namely, n!.
Love waves Basic theory Love_wave > Basic theory The conservation of linear momentum of a linear elastic material can be written as ∇ ⋅ ( C: ∇ u ) = ρ u ¨ {\displaystyle {\boldsymbol {\nabla }}\cdot ({\mathsf {C}}:{\boldsymbol {\nabla }}\mathbf {u} )=\rho ~{\ddot {\mathbf {u} }}} where u {\displaystyle \mathbf {u} } is the displacement vector and C {\displaystyle {\mathsf {C}}} is the stiffness tensor. Love waves are a special solution ( u {\displaystyle \mathbf {u} } ) that satisfy this system of equations. We typically use a Cartesian coordinate system ( x , y , z {\displaystyle x,y,z} ) to describe Love waves. Consider an isotropic linear elastic medium in which the elastic properties are functions of only the z {\displaystyle z} coordinate, i.e., the Lamé parameters and the mass density can be expressed as λ ( z ) , μ ( z ) , ρ ( z ) {\displaystyle \lambda (z),\mu (z),\rho (z)} .
Reaction center Photosystem II Reaction_Centre > In Cyanobacteria and plants > Photosystem II In the bacterial reaction center, the electron is obtained from a reduced compound haem group in a cytochrome subunit or from a water-soluble cytochrome-c protein. Every time the P680 absorbs a photon, it gives off an electron to pheophytin, gaining a positive charge. After this photoinduced charge separation, P680+ is a very strong oxidant of high energy.
Glycerate pathway Plants Glycerate_pathway > Biological role > Plants However, this pathway comes at a decreased return on investment ratio as 2-PG is transformed to 3-phosphoglycerate in an elaborate salvage pathway at the cost of one equivalent of NADH and ATP, respectively. In addition, this salvage pathway loses ½ equivalent of previously fixed carbon dioxide and releases ½ equivalent of toxic ammonia per molecule of 2-PG. This leads to a net loss of carbon in photorespiration, making it much less efficient than the Calvin cycle. However, this salvage pathway can also act as a cellular energy sink, preventing the chloroplastidal electron transport chain from over reduction. It is believed that this pathway also plays a role in improving the abiotic stress response of plants.
Foam cells Infectious diseases Foam_cell > Infectious diseases Foamy macrophages are also found in diseases caused by pathogens that persist in the body, such as Chlamydia, Toxoplasma, or Mycobacterium tuberculosis. In tuberculosis (TB), bacterial lipids disable macrophages from pumping out excess LDL, causing them to turn into foam cells around the TB granulomas in the lung. The cholesterol forms a rich food source for the bacteria. As the macrophages die, the mass of cholesterol in the center of the granuloma becomes a cheesy substance called caseum.
Short interspersed element LTR retrotransposons Short_interspersed_element > LTR retrotransposons Ribonuclease cleaves phosphodiester bonds between RNA nucleotides. LTR retrotransposons encode transcripts with tRNA binding sites so that they can undergo reverse transcription. The tRNA-bound RNA transcript binds to a genomic RNA sequence.
Dataflow analysis Backward analysis Flow_analysis > Examples > Backward analysis The transfer function of a statement is applied by killing the variables that are written within this block (remove them from the set of live variables). The out-state of a block is the set of variables that are live at the end of the block and is computed by the union of the block's successors' in-states. Initial code: Backward analysis: The in-state of b3 only contains b and d, since c has been written.
Cardiac arrest Diagnosis Cardiac_arrest > Diagnosis In many cases, lack of a carotid pulse is the gold standard for diagnosing cardiac arrest. Lack of a pulse in the periphery (radial/pedal) may also result from other conditions (e.g. shock) or simply an error on the part of the rescuer. Studies have shown that rescuers may often make a mistake when checking the carotid pulse in an emergency, whether they are healthcare professionals or lay persons.Point-of-care ultrasound (POCUS) is a tool that can be used to examine the movement of the heart and its force of contraction at the patient's bedside.
Prion disease Replication Prion_disease > Replication The first hypothesis that tried to explain how prions replicate in a protein-only manner was the heterodimer model. This model assumed that a single PrPSc molecule binds to a single PrPC molecule and catalyzes its conversion into PrPSc. The two PrPSc molecules then come apart and can go on to convert more PrPC. However, a model of prion replication must explain both how prions propagate, and why their spontaneous appearance is so rare.
Outline of water History Outline_of_water > History The identification of water as a substance
Macrorestriction map Genetic mapping Genome_mapping > Mapping approaches > Genetic mapping Researchers begin a genetic map by collecting samples of blood, saliva, or tissue from family members that carry a prominent disease or trait and family members that do not. The most common sample used in gene mapping, especially in personal genomic tests is saliva. Scientists then isolate DNA from the samples and closely examine it, looking for unique patterns in the DNA of the family members who do carry the disease and the DNA of those who do not carry the disease do not have. These unique molecular patterns in the DNA are referred to as polymorphisms, or markers.The first steps of building a genetic map are the development of genetic markers and a mapping population.
National Centre for the Evaluation of Photoprotection Summary National_Centre_for_the_Evaluation_of_Photoprotection The CNEP functions as a specialized research center with a primary focus on the prediction of durability and analysis of failures in plastic (polymer) materials. The ubiquity of plastics in various applications, from everyday use to advanced contexts, emphasizes the necessity to enhance their reliability. These materials are susceptible to failures during their usage lifespan, necessitating an approach similar to medical diagnostics for identifying failure causes and proposing effective remedies.
Platinum silicide Structure and bonding Platinum_silicide > Structure and bonding The crystal structure of PtSi is orthorhombic, with each silicon atom having six neighboring platinum atoms. The distances between the silicon and the platinum neighbors are as follows: one at a distance of 2.41 angstroms, two at a distance of 2.43 angstroms, one at a distance of 2.52 angstroms, and the final two at a distance of 2.64 angstroms. Each platinum atom has six silicon neighbors at the same distances, as well as two platinum neighbors, at a distance of 2.87 and 2.90 angstroms. All of the distances over 2.50 angstroms are considered too far to really be involved in bonding interactions of the compound.
Parkinson disease History Parkinsonian_tremor > History An Essay on the Shaking Palsy described the characteristic resting tremor, abnormal posture and gait, paralysis and diminished muscle strength, and the way that the disease progresses over time. Early neurologists who made further additions to the knowledge of the disease include Trousseau, Gowers, Kinnier Wilson and Erb, and Jean-Martin Charcot, whose studies between 1868 and 1881 increased the understanding of the disease. Among other advances, he made the distinction between rigidity, weakness and bradykinesia.
Red–black tree Analogy to B-trees of order 4 Red–black_tree > Analogy to B-trees of order 4 Instead, you have to know which slot in the cluster vector is used. If values are stored by reference, e. g. objects, null references can be used and so the cluster can be represented by a vector containing 3 slots for value pointers plus 4 slots for child references in the tree.
Process graph Description Process_graph > Description With a process graph, the vertices of the graph are of two types, operation (O) and material (M). These vertex types form two disjunctive sets. The edges of the graph link the O and M vertices. An edge from an operation vertex (O) connects to a material vertex (M) if M is the output of O, such as a 'document' (material) that is output by a 'write-up' (operation). An edge from M to O indicates that M is an element of the input set of O, e.g. a document may be part of the input to a 'review' operation.
Ventricular natriuretic peptide Renal Ventricular_natriuretic_peptide > Physiologic effects > Renal The lower osmolarity of the medullary interstitium leads to less reabsorption of tubular fluid and increased excretion. Decreases sodium reabsorption in the distal convoluted tubule (interaction with NCC) and cortical collecting duct of the nephron via guanosine 3',5'-cyclic monophosphate (cGMP) dependent phosphorylation of ENaC. Inhibits renin secretion, thereby inhibiting the renin–angiotensin–aldosterone system.
Thermodynamic free energy Summary Free_energy_(thermodynamics) The Helmholtz free energy has a special theoretical importance since it is proportional to the logarithm of the partition function for the canonical ensemble in statistical mechanics. (Hence its utility to physicists; and to gas-phase chemists and engineers, who do not want to ignore p dV work.) Historically, the term 'free energy' has been used for either quantity. In physics, free energy most often refers to the Helmholtz free energy, denoted by A (or F), while in chemistry, free energy most often refers to the Gibbs free energy. The values of the two free energies are usually quite similar and the intended free energy function is often implicit in manuscripts and presentations.
Safety capacitor Safety and EMI/RFI suppression film capacitors Power_capacitor > Applications > Safety and EMI/RFI suppression film capacitors RFI/EMI suppression capacitors Electromagnetic interference (EMI) or radio-frequency interference (RFI) suppression film capacitors, also known as "AC line filter safety capacitors" or "Safety capacitors", are used as crucial components to reduce or suppress electrical noise caused by the operation of electrical or electronic equipment, while also providing limited protection against electrical shocks.A suppression capacitor is an effective interference reduction component because its electrical impedance decreases with increasing frequency, so that at higher frequencies they short circuit electrical noise and transients between the lines, or to ground. They therefore prevent equipment and machinery (including motors, inverters, and electronic ballasts, as well as solid-state relay snubbers and spark quenchers) from sending and receiving electromagnetic and radio frequency interference as well as transients in across-the-line (X capacitors) and line-to-ground (Y capacitors) connections. X capacitors effectively absorb symmetrical, balanced, or differential interference. On the other hand, Y capacitors are connected in a line bypass between a line phase and a point of zero potential, to absorb asymmetrical, unbalanced, or common-mode interference.
Biostatistics Bioinformatics advances in databases, data mining, and biological interpretation Biostatistics > Developments and big data > Bioinformatics advances in databases, data mining, and biological interpretation In addition to databases that contain specific molecular information, there are others that are ample in the sense that they store information about an organism or group of organisms. As an example of a database directed towards just one organism, but that contains much data about it, is the Arabidopsis thaliana genetic and molecular database – TAIR. Phytozome, in turn, stores the assemblies and annotation files of dozen of plant genomes, also containing visualization and analysis tools.
Gas exchange Pulmonary circulation Gas_exchange > Mammals > Pulmonary circulation The oxygen is held on the hemoglobin by four ferrous iron-containing heme groups per hemoglobin molecule. When all the heme groups carry one O2 molecule each the blood is said to be "saturated" with oxygen, and no further increase in the partial pressure of oxygen will meaningfully increase the oxygen concentration of the blood. Most of the carbon dioxide in the blood is carried as HCO3− ions in the plasma.
Carbonyl ligand Analytical characterization Metal_carbonyls > Analytical characterization Apart from X-ray crystallography, important analytical techniques for the characterization of metal carbonyls are infrared spectroscopy and 13C NMR spectroscopy. These two techniques provide structural information on two very different time scales. Infrared-active vibrational modes, such as CO-stretching vibrations, are often fast compared to intramolecular processes, whereas NMR transitions occur at lower frequencies and thus sample structures on a time scale that, it turns out, is comparable to the rate of intramolecular ligand exchange processes.
Discrete-time Markov chain Periodicity Discrete-time_Markov_chain > Communicating classes and properties > Periodicity Note that even though a state has period k {\displaystyle k} , it may not be possible to reach the state in k {\displaystyle k} steps. For example, suppose it is possible to return to the state in { 6 , 8 , 10 , 12 , … } {\displaystyle \{6,~8,~10,~12,\dots \}} time steps; k {\displaystyle k} would be 2 {\displaystyle 2} , even though 2 {\displaystyle 2} does not appear in this list. If k = 1 {\displaystyle k=1} , then the state is said to be aperiodic. Otherwise ( k > 1 {\displaystyle k>1} ), the state is said to be periodic with period k {\displaystyle k} . Periodicity is a class property—that is, if a state has period k {\displaystyle k} then every state in its communicating class has period k {\displaystyle k} .
Metalloid staircase Boron Metalloid > Elements commonly recognised as metalloids > Boron The same motif can be seen, as are deltahedral variants or fragments, in metal borides and hydride derivatives, and in some halides.The bonding in boron has been described as being characteristic of behaviour intermediate between metals and nonmetallic covalent network solids (such as diamond). The energy required to transform B, C, N, Si, and P from nonmetallic to metallic states has been estimated as 30, 100, 240, 33, and 50 kJ/mol, respectively. This indicates the proximity of boron to the metal-nonmetal borderline.Most of the chemistry of boron is nonmetallic in nature.
Pluralism (political theory) Pluralist conception of power Pluralism_(political_theory) > Pluralist conception of power The list of possible sources of power is virtually endless: legal authority, money, prestige, skill, knowledge, charisma, legitimacy, free time, and experience. Pluralists also stress the differences between potential and actual power as it stands. Actual power means the ability to compel someone to do something and is the view of power as a causation. Dahl describes power as a "realistic relationship, such as A's capacity for acting in such a manner as to control B's responses".Potential power refers to the possibility of turning resources into actual power.