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Concept formation Component display theory Concept_learning > Modern psychological theories > Component display theory Secondary presentation forms include: prerequisites, objectives, helps, mnemonics, and feedback. A complete lesson includes a combination of primary and secondary presentation forms, but the most effective combination varies from learner to learner and also from concept to concept. Another significant aspect of the CDT model is that it allows for the learner to control the instructional strategies used and adapt them to meet his or her own learning style and preference. A major goal of this model was to reduce three common errors in concept formation: over-generalization, under-generalization and misconception.
Kepler-1649c Summary Kepler-1649c In 2017, Jeff Coughlin, the director of SETI's K2 Science Office, described it as the most "similar planet to Earth" found so far by the Kepler Space Telescope. The planet was initially deemed a false positive by Kepler's robovetter algorithm. The Kepler False Positive Working Group published its recovery on April 15, 2020. Its first scientific description was published in The Astrophysical Journal Letters, with first author Andrew Vanderburg, in April 2020.
Hartman effect Summary Hartman_effect The Hartman effect describes how the delay time for a quantum tunneling particle is independent of the thickness of the opaque barrier. It is named after Thomas Hartman, who discovered it in 1962.
Integer partition function Young's lattice Partition_of_an_integer > Young's lattice There is a natural partial order on partitions given by inclusion of Young diagrams. This partially ordered set is known as Young's lattice. The lattice was originally defined in the context of representation theory, where it is used to describe the irreducible representations of symmetric groups Sn for all n, together with their branching properties, in characteristic zero. It also has received significant study for its purely combinatorial properties; notably, it is the motivating example of a differential poset.
Data link layer Relation to the TCP/IP model Data_link_layer > Relation to the TCP/IP model It was formulated for the purpose of illustrating the logical groups and scopes of functions needed in the design of the suite of internetworking protocols of TCP/IP, as needed for the operation of the Internet. In general, direct or strict comparisons of the OSI and TCP/IP models should be avoided, because the layering in TCP/IP is not a principal design criterion and in general, considered to be "harmful" (RFC 3439). In particular, TCP/IP does not dictate a strict hierarchical sequence of encapsulation requirements, as is attributed to OSI protocols.
C programming language Language tools C_programming_language > Language tools A number of tools have been developed to help C programmers find and fix statements with undefined behavior or possibly erroneous expressions, with greater rigor than that provided by the compiler. The tool lint was the first such, leading to many others. Automated source code checking and auditing are beneficial in any language, and for C many such tools exist, such as Lint. A common practice is to use Lint to detect questionable code when a program is first written.
Tumor metabolome Role of tumor suppressor and oncogenes Tumor_metabolome > Warburg effect and glycolysis > Role of tumor suppressor and oncogenes Apart from being as a general tumor suppressor gene, p53 also plays an important part in regulating of metabolism. p53 activates hexokinase 2 (HK2) that converts glucose to glucose-6-phosphate (G6P) which enters glycolysis to produce ATP, or enters the pentose phosphate pathway (PPP). It therefore, supports macromolecular biosynthesis by producing reducing potential in the form of reduced Nicotinamide adenine dinucleotide phosphate (NADPH) and/or ribose that are used for nucleotide synthesis. p53 inhibits the glycolytic pathway by upregulating the expression of TP53-induced glycolysis and apoptosis regulator.
Satellite orbit Principles Orbit_(celestial_mechanics) > Principles There are a few common ways of understanding orbits: A force, such as gravity, pulls an object into a curved path as it attempts to fly off in a straight line. As the object is pulled toward the massive body, it falls toward that body. However, if it has enough tangential velocity it will not fall into the body but will instead continue to follow the curved trajectory caused by that body indefinitely. The object is then said to be orbiting the body.The velocity relationship of two moving objects with mass can thus be considered in four practical classes, with subtypes: No orbit Suborbital trajectories Range of interrupted elliptical paths Orbital trajectories (or simply, orbits) Open (or escape) trajectories It is worth noting that orbital rockets are launched vertically at first to lift the rocket above the atmosphere (which causes frictional drag), and then slowly pitch over and finish firing the rocket engine parallel to the atmosphere to achieve orbit speed.
Renin inhibitors History Renin_inhibitor > History They had more drug-like rather than substrate-like properties, and in 1990 they went to clinical trials. The second generation had its limitations and never completed clinical trials.Aliskiren, the only renin inhibitor to go into phase III clinical trials, is not structurally related to peptides, which makes it a third-generation renin inhibitor. The first clinical trial was performed in 2000 in healthy volunteers. In 2007, aliskiren was approved by the US Food and Drug Administration and the European Medicines Agency as a treatment for hypertension. A systematic review by the Cochrane Hypertension group found the maximum recommended dose of aliskiren produced an appreciable decline in blood pressure over placebo.
Static temperature Theoretical foundation Kinetic_temperature > Theoretical foundation Temperature determines the statistical occupation of the microstates of the ensemble. The microscopic definition of temperature is only meaningful in the thermodynamic limit, meaning for large ensembles of states or particles, to fulfill the requirements of the statistical model. Kinetic energy is also considered as a component of thermal energy.
Bivector (complex) Summary Bivector_(complex) "The commutator product of this Lie algebra is just twice the cross product on R3, for instance, = ij − ji = 2k, which is twice i × j. As Shaw wrote in 1970: Now it is well known that the Lie algebra of the homogeneous Lorentz group can be considered to be that of bivectors under commutation. The Lie algebra of bivectors is essentially that of complex 3-vectors, with the Lie product being defined to be the familiar cross product in (complex) 3-dimensional space.William Rowan Hamilton coined both the terms vector and bivector. The first term was named with quaternions, and the second about a decade later, as in Lectures on Quaternions (1853).
Stem Cells Embryonic Stem_Cell_Research > Embryonic Without optimal culture conditions or genetic manipulation, embryonic stem cells will rapidly differentiate. A human embryonic stem cell is also defined by the expression of several transcription factors and cell surface proteins. The transcription factors Oct-4, Nanog, and Sox2 form the core regulatory network that ensures the suppression of genes that lead to differentiation and the maintenance of pluripotency.
Transport layer Services Transport_layer > Services Multiplexing: Ports can provide multiple endpoints on a single node. For example, the name on a postal address is a kind of multiplexing and distinguishes between different recipients of the same location. Computer applications will each listen for information on their own ports, which enables the use of more than one network service at the same time. It is part of the transport layer in the TCP/IP model, but of the session layer in the OSI model.
European Prospective Investigation into Cancer and Nutrition Summary European_Prospective_Investigation_into_Cancer_and_Nutrition Up to 2004, there were over 26,000 new cases of cancer recorded among participants, with the most common being cancers of the breast, colorectum, prostate and lung. Current analyses are focusing particularly on stomach, colorectal, breast, prostate and lung cancers. The different dietary patterns in the different countries should enable reliable associations to be made between particular diets and cancers. The analysis of stored blood samples should also allow dissection of genetic factors involved in cancers, as well as the effects of hormones and hormone-like factors.
Protein aggregation In biomanufacturing Protein_aggregation > In biomanufacturing Protein aggregation is also a common phenomenon in the biopharmaceutical manufacturing process, which may pose risks to patients via generating adverse immune responses.
Polymerase Chain Reaction Forensic applications Polymerase_Chain_Reaction > Applications > Forensic applications Less discriminating forms of DNA fingerprinting can help in DNA paternity testing, where an individual is matched with their close relatives. DNA from unidentified human remains can be tested, and compared with that from possible parents, siblings, or children. Similar testing can be used to confirm the biological parents of an adopted (or kidnapped) child.
Theoretical motivation for general relativity Solving the Einstein field equation Theoretical_motivation_for_general_relativity > Solving the Einstein field equation Solving the Einstein field equation requires an iterative process. The solution is represented in the metric tensor g μ ν {\displaystyle g_{\mu \nu }} .Typically there is an initial guess for the tensor. The guess is used to calculate Christoffel symbols, which are used to calculate the curvature. If the Einstein field equation is not satisfied, the process is repeated.
Machine learning in bioinformatics antiSMASH Machine_learning_in_bioinformatics > Databases > Bioinformatics analysis for biosynthetic gene clusters > antiSMASH antiSMASH allows the rapid genome-wide identification, annotation and analysis of secondary metabolite biosynthesis gene clusters in bacterial and fungal genomes. It integrates and cross-links with a large number of in silico secondary metabolite analysis tools.
K-d tree Construction K-d_tree > Operations on k-d trees > Construction Points that lie on the splitting plane may appear on either side. The splitting plane of a node goes through the point associated with that node (referred to in the code as node.location). Alternative algorithms for building a balanced k-d tree presort the data prior to building the tree.
Werner Heisenberg Matrix mechanics and the Nobel Prize Werner_Heisenberg > Academic career > Matrix mechanics and the Nobel Prize So Heisenberg set out to formulate these results without any explicit dependence on the virtual oscillator model. To do this, he replaced the Fourier expansions for the spatial coordinates with matrices, matrices which corresponded to the transition coefficients in the virtual oscillator method. He justified this replacement by an appeal to Bohr's correspondence principle and the Pauli doctrine that quantum mechanics must be limited to observables.
Long-term memories Encoding of information Long-term_memory > Encoding of information In LTM, brain cells fire in specific patterns. When someone experiences something in the world, the brain responds by creating a pattern of specific nerves firing in a specific way to represent the experience. This is called distributed representation.
Thermionic tube Vacuum tubes using field electron emitters Vacuum_tube > Vacuum tubes in the 21st century > Vacuum tubes using field electron emitters In the early years of the 21st century there has been renewed interest in vacuum tubes, this time with the electron emitter formed on a flat silicon substrate, as in integrated circuit technology. This subject is now called vacuum nanoelectronics. The most common design uses a cold cathode in the form of a large-area field electron source (for example a field emitter array).
Peer group Future problems Peer_group > Negative attributes (disadvantages) > Future problems Success of peer relationships is linked to later psychological development and to academic achievement. Therefore, if one does not have successful peer relationships it may lead to developmental delays and poor academic achievement—perhaps even in-completion of a high school degree. Children with poor peer relationships may also experience job related and marital problems later in life.
Dimension analysis Mathematical properties Unit_commensurability > Properties > Mathematical properties Every possible way of multiplying (and exponentiating) together the measured quantities to produce something with the same unit as some derived quantity X can be expressed in the general form X = ∏ i = 1 m ( π i ) k i . {\displaystyle X=\prod _{i=1}^{m}(\pi _{i})^{k_{i}}\,.} Consequently, every possible commensurate equation for the physics of the system can be rewritten in the form f ( π 1 , π 2 , .
Distributed denial-of-service attacks on root nameservers Summary Distributed_denial_of_service_attacks_on_root_nameservers Distributed denial-of-service attacks on root nameservers are Internet events in which distributed denial-of-service attacks target one or more of the thirteen Domain Name System root nameserver clusters. The root nameservers are critical infrastructure components of the Internet, mapping domain names to IP addresses and other resource record (RR) data. Attacks against the root nameservers could, in theory, impact operation of the entire global Domain Name System, and thus all Internet services that use the global DNS, rather than just specific websites. However, in practice, the root nameserver infrastructure is highly resilient and distributed, using both the inherent features of DNS (result caching, retries, and multiple servers for the same zone with fallback if one or more fail), and, in recent years, a combination of anycast and load balancer techniques used to implement most of the thirteen nominal individual root servers as globally distributed clusters of servers in multiple data centers.
Traffic policing (communications) Summary Traffic_policing_(communications) In communications, traffic policing is the process of monitoring network traffic for compliance with a traffic contract and taking steps to enforce that contract. Traffic sources which are aware of a traffic contract may apply traffic shaping to ensure their output stays within the contract and is thus not discarded. Traffic exceeding a traffic contract may be discarded immediately, marked as non-compliant, or left as-is, depending on administrative policy and the characteristics of the excess traffic.
Equilibrium reaction Historical introduction Chemical_equilibria > Historical introduction Despite the limitations of this derivation, the equilibrium constant for a reaction is indeed a constant, independent of the activities of the various species involved, though it does depend on temperature as observed by the van 't Hoff equation. Adding a catalyst will affect both the forward reaction and the reverse reaction in the same way and will not have an effect on the equilibrium constant. The catalyst will speed up both reactions thereby increasing the speed at which equilibrium is reached.Although the macroscopic equilibrium concentrations are constant in time, reactions do occur at the molecular level.
Accelerometer Structure Acceleration_sensor > Structure It contains a small heater in a very small dome. This heats the air or other fluid inside the dome. The thermal bubble acts as the proof mass.
Carbonyl ligand Nomenclature and terminology Metal_carbonyls > Nomenclature and terminology More commonly only carbon is bonded, in which case the hapticity is not mentioned.The carbonyl ligand engages in a wide range of bonding modes in metal carbonyl dimers and clusters. In the most common bridging mode, denoted μ2 or simply μ, the CO ligand bridges a pair of metals. This bonding mode is observed in the commonly available metal carbonyls: Co2(CO)8, Fe2(CO)9, Fe3(CO)12, and Co4(CO)12.
Nanotribology Friction Nanotribology > Properties > Friction Without considering thermal effects, the only force that makes the tip overcome these potential barriers is the spring force given by the support: this causes the stick-slip motion. At the nanoscale, friction coefficient depends on several conditions.
79 (number) In mathematics 79_(number) > In mathematics A right-truncatable prime, because when the last digit (9) is removed, the remaining number (7) is still prime. A sexy prime (with 73). The n value of the Wagstaff prime 201487636602438195784363.
Ontotext GraphDB Uses Ontotext_GraphDB > Uses Ontotext Graph DB is used in various scientific areas, e.g., Genetics, Healthcare, Data Forensics, Cultural Heritage, Geography, Infrastructure Planning, Civil Engineering, Digital Historiography, Oceanography.For more examples see "Diverse Uses of a Semantic Graph Database for Knowledge Organization and Research" below. Commercial clients include BBC Sport, Financial Times, Springer Nature, UK Parliament, AstraZeneca as well as in the pharmaceutical and finance industries. Some use cases focus on scalability and large data sizes.
Stop codon Nonstop Termination_codon > Mutations and disease > Nonstop A nonstop mutation, also called a stop-loss variant, is a point mutation that occurs within a stop codon. Nonstop mutations cause the continued translation of an mRNA strand into what should be an untranslated region. Most polypeptides resulting from a gene with a nonstop mutation lose their function due to their extreme length and the impact on normal folding.
Heavy Rydberg system Species Heavy_Rydberg_system > Species The most commonly studied system to date is the H + / H − {\displaystyle H^{+}/H^{-}} system, consisting of a proton bound with a H − {\displaystyle H^{-}} ion. The H + / H − {\displaystyle H^{+}/H^{-}} system was first observed in 2000 by a group at the University of Waterloo in Canada. The formation of the H − {\displaystyle H^{-}} ion can be understood classically; as the single electron in a hydrogen atom cannot fully shield the positively charged nucleus, another electron brought into close proximity will feel an attractive force. While this classical description is nice for getting a feel for the interactions involved, it is an oversimplification; many other atoms have a greater electron affinity than hydrogen.
Frictional contact mechanics Problem formulation Frictional_contact_mechanics > Problem formulation Finally there are the processes at the contact interface: compression and adhesion in the direction perpendicular to the interface, and friction and micro-slip in the tangential directions.The last aspect is the primary concern of contact mechanics. It is described in terms of so-called contact conditions.
Fork–join queue Applications Fork–join_queue > Applications Fork–join queues have been used to model zoned RAID systems, parallel computations and for modelling order fulfilment in warehouses.
Federated learning Definition Federated_learning > Definition While distributed learning also aims at training a single model on multiple servers, a common underlying assumption is that the local datasets are independent and identically distributed (i.i.d.) and roughly have the same size. None of these hypotheses are made for federated learning; instead, the datasets are typically heterogeneous and their sizes may span several orders of magnitude. Moreover, the clients involved in federated learning may be unreliable as they are subject to more failures or drop out since they commonly rely on less powerful communication media (i.e. Wi-Fi) and battery-powered systems (i.e. smartphones and IoT devices) compared to distributed learning where nodes are typically datacenters that have powerful computational capabilities and are connected to one another with fast networks.
Rebreather diving Scrubber failure Rebreather_diving > Safety > Failure modes > Scrubber failure Whether this is technically a failure of the scrubber design, the selection of absorbent material, the selection of breathing gas, or of the rebreather as a system is open to interpretation.Consequences: The failure to remove carbon dioxide from the breathing gas results in a buildup of carbon dioxide leading to hypercapnia. This may occur gradually, over several minutes, with enough warning to the diver to bail out, or may happen in seconds, often associated with a sudden increase in depth which proportionately increases the partial pressure of the carbon dioxide, and when this happens the onset of symptoms may be so sudden and extreme that the diver is unable to control their breathing sufficiently to close and remove the DSV and swap it for a bailout regulator. This problem can be mitigated by using a bailout valve built into the rebreather mouthpiece which allows switch-over between the loop and open circuit without taking the mouthpiece out.Prevention: An indicating dye in the soda lime which changes the colour of the soda lime after the active ingredient is consumed may be used.
Neuroepigenetics Hypomethylation and aberrant histone modification Neuroepigenetics > Mechanisms > Hypomethylation and aberrant histone modification For example, expression of MAGEA1 enhanced by hypomethylation interferes with p53 function.Aberrant patterns of histone modifications can also take place at specific loci and ultimately manipulate gene activity. In terms of CGI promoter sites, methylation and loss of acetylation occurs frequently at H3K9. Furthermore, H3K9 dimethylation and trimethylation are repressive marks which, along with bivalent differentially methylated domains, are hypothesized to make tumor suppressing genes more susceptible to silencing.
Iberian language Semivowels Iberian_language > Phonology > Semivowels It is possible that Iberian had the semivowels /j/ (in words such as aiun or iunstir) and /w/ (only in loanwords such as diuiś from Gaulish). The fact that /w/ is lacking in native words casts doubt on whether semivowels really existed in Iberian outside of foreign borrowings and diphthongs.
Elementary particles Higgs boson Elementary_particles > Standard Model > Fundamental bosons > Higgs boson On 4 July 2012, after many years of experimentally searching for evidence of its existence, the Higgs boson was announced to have been observed at CERN's Large Hadron Collider. Peter Higgs who first posited the existence of the Higgs boson was present at the announcement. The Higgs boson is believed to have a mass of approximately 125 GeV.
Groupoid scheme Groupoid schemes Groupoid_object > Examples > Groupoid schemes A groupoid S-scheme is a groupoid object in the category of schemes over some fixed base scheme S. If U = S {\displaystyle U=S} , then a groupoid scheme (where s = t {\displaystyle s=t} are necessarily the structure map) is the same as a group scheme. A groupoid scheme is also called an algebraic groupoid, to convey the idea it is a generalization of algebraic groups and their actions. For example, suppose an algebraic group G acts from the right on a scheme U. Then take R = U × G {\displaystyle R=U\times G} , s the projection, t the given action. This determines a groupoid scheme.
Tail-recursive function Through trampolining Tail_call > Implementation methods > Through trampolining This ensures that the C stack does not grow and iteration can continue indefinitely. It is possible to implement trampolines using higher-order functions in languages that support them, such as Groovy, Visual Basic .NET and C#.Using a trampoline for all function calls is rather more expensive than the normal C function call, so at least one Scheme compiler, Chicken, uses a technique first described by Henry Baker from an unpublished suggestion by Andrew Appel, in which normal C calls are used but the stack size is checked before every call. When the stack reaches its maximum permitted size, objects on the stack are garbage-collected using the Cheney algorithm by moving all live data into a separate heap.
Oxidative damage Metal catalysts Oxidant_stress > Metal catalysts The hydroxyl radical then can modify amino acids. For example, meta-tyrosine and ortho-tyrosine form by hydroxylation of phenylalanine.
AOT compilation Summary AOT_compilation In computer science, ahead-of-time compilation (AOT compilation) is the act of compiling an (often) higher-level programming language into an (often) lower-level language before execution of a program, usually at build-time, to reduce the amount of work needed to be performed at run time. Most often, It is associated with the act of compiling a higher-level programming language such as C or C++, or an intermediate representation such as Java bytecode or .NET Framework Common Intermediate Language (CIL) code, into a native (system-dependent) machine code so that the resulting binary file can execute natively, just like a standard native compiler. When being used in this specific context, it is often seen as an opposite of just-in-time (JIT) compiling.
Engine efficiency Stirling engines Engine_efficiency > External combustion engines > Stirling engines The Stirling engine has the highest theoretical efficiency of any thermal engine but it has a low output power to weight ratio, therefore Stirling engines of practical output tend to be large. The size effect of the Stirling engine is due to its reliance on the expansion of a gas with an increase in temperature and practical limits on the working temperature of engine components. For an ideal gas, increasing its absolute temperature for a given volume, only increases its pressure proportionally, therefore, where the low pressure of the Stirling engine is atmospheric, its practical pressure difference is constrained by temperature limits and is typically not more than a couple of atmospheres, making the piston pressures of the Stirling engine very low, hence relatively large piston areas are required to obtain useful output power.
Reward system Mood disorders Appetitive_behaviour > Disorders > Motivation > Mood disorders Although these differences may be attributable to different stimulation protocols or poor translational paradigms, variable results may also lie in the heterogenous functionality of reward related regions.Optogenetic stimulation of the mPFC as a whole produces antidepressant effects. This effect appears localized to the rodent homologue of the pgACC (the prelimbic cortex), as stimulation of the rodent homologue of the sgACC (the infralimbic cortex) produces no behavioral effects. Furthermore, deep brain stimulation in the infralimbic cortex, which is thought to have an inhibitory effect, also produces an antidepressant effect. This finding is congruent with the observation that pharmacological inhibition of the infralimbic cortex attenuates depressive behaviors.
Vector multiplication Summary Vector_multiplication So, if n̂ is the unit vector perpendicular to the plane determined by vectors A and B, A ⟶ {\displaystyle {\stackrel {\,\longrightarrow }{A}}} × B ⟶ {\displaystyle {\stackrel {\,\longrightarrow }{B}}} = \| A ⟶ {\displaystyle {\stackrel {\,\longrightarrow }{A}}} \| \| B ⟶ {\displaystyle {\stackrel {\,\longrightarrow }{B}}} \| sin θ n̂More generally, a Lie bracket in a Lie algebra. Hadamard product – entrywise or elementwise product of vectors, where ( A ⊙ B ) i = A i B i {\displaystyle (A\odot B)_{i}=A_{i}B_{i}} . Outer product - where ( a ⊗ b ) {\displaystyle (\mathbf {a} \otimes \mathbf {b} )} with a ∈ R d , b ∈ R d {\displaystyle \mathbf {a} \in \mathbb {R} ^{d},\mathbf {b} \in \mathbb {R} ^{d}} results in a ( d × d ) {\displaystyle (d\times d)} matrix. Triple products – products involving three vectors. Quadruple products – products involving four vectors.
Social self Precursors Social_self > Precursors Helene Deutsch, a colleague of Freud, had previously described "as if" personalities, pseudo-relationships substituting for real ones. Winnicott's analyst, Joan Riviere, had also explored the concept of the narcissist's masquerade, which is essentially a superficial assent concealing a subtle hidden struggle for control. Freud's own late theory of the ego as the product of identifications came close to viewing it only as a false self; while Winnicott's true/false distinction has also been compared to Michael Balint's "basic fault" and to Ronald Fairbairn's notion of the "compromised ego".Erich Fromm, in his 1941 book The Fear of Freedom distinguished between original self and pseudo self—the inauthenticality of the latter being a way to escape the loneliness of freedom; while much earlier existentialists such as Søren Kierkegaard had claimed that "to will to be that self which one truly is, is indeed the opposite of despair"—the despair of choosing "to be another than himself".Karen Horney, in her 1950 book, Neurosis and Human Growth, based her idea of "true self" and "false self" through the view of self-improvement, interpreting it as real self and ideal self, with the real self being what one currently is and the ideal self being what one could become. (See also Karen Horney § Theory of the self).
Base catalyst Summary Base_catalyst In these reactions, the conjugate acid of the carbonyl group is a better electrophile than the neutral carbonyl group itself. Depending on the chemical species that act as the acid or base, catalytic mechanisms can be classified as either specific catalysis and general catalysis. Many enzymes operate by general catalysis.
Carbon respiration Summary Carbon_respiration Carbon respiration (also called carbon emissions and carbon releases) is used in combination with carbon fixation to gauge carbon flux (as CO2) between atmospheric carbon and the global carbon cycle
Tumor microenvironment TAMs and MDSCs Tumor_microenvironment > Immune cells > T cells > TAMs and MDSCs Similarly, an activator of TAMs, an agonistic antibody to CD40, when administered in combination with the chemotherapeutic drug gemcitabine, suppressed mouse PDA growth in a T cell–independent manner, suggesting that stimulated macrophages may have anticancer functions.B cells regulate TAM phenotypes in squamous cell carcinoma TME. Correspondingly, B cell depletion reprogrammed TAMs, thus reducing their suppression of CD8 cells and enhancing chemotherapy. An autochthonous melanoma mouse model depleted Treg cells and neutralized IL-10, revealing tumor-killing properties. TAMs mediate the effects of antitumor antibodies and genetically engineered ligands that interact with CD47 to prevent the CD47/signal regulatory protein–α (SIRPα) signaling system from suppressing antibody-coated cancer cell phagocytosis.
Hepatic portal system Summary Hepatic_portal_system In human anatomy, the hepatic portal system or portal venous system is the system of veins comprising the portal vein and its tributaries. The other portal venous systems in the body are the renal portal system, and the hypophyseal portal system.
Cancer Stem Cells Heterogeneity (markers) Cancer_stem_cell > Heterogeneity (markers) CSCs heterogeneity is a pool of differentiated and undifferentiated tumour cells that are replenished by cells possessing both tumour and stem cell like properties and having phenotypic and metabolic heterogeneity inside the single tumour mass. There are two theories to explain the phenotypic and metabolic heterogeneity of CSCs; clonal variation and cancer stem cell theory. While former theory dictates the role of genetic, epigenetic and micro environment where tumour cell resides to acquire undifferentiated tumorigenic traits. The latter theory focus more on the malignancy traits acquired by stem cells where these undifferentiated and highly tumorigenic stem cells repopulate the differentiated tumour mass.CSCs have been identified in various solid tumors.
Dot distribution map Types of dot maps Dot_distribution_map > Types of dot maps Two very different types of dot maps have been developed, often leading to some confusion in terminology. In fact, many cartographers have suggested that they not be grouped into a single type of thematic map. Although they use very different techniques, based on very different data sources, with a different semantics in the result, the general purpose is the same: to visualize the geographic distribution of a group phenomenon (i.e. a large number of individuals).
UV Sterilizer Aquarium and pond UV_irradiation > Uses > Aquarium and pond Ultraviolet sterilizers are often used to help control unwanted microorganisms in aquaria and ponds. UV irradiation ensures that pathogens cannot reproduce, thus decreasing the likelihood of a disease outbreak in an aquarium. Aquarium and pond sterilizers are typically small, with fittings for tubing that allows the water to flow through the sterilizer on its way from a separate external filter or water pump. Within the sterilizer, water flows as close as possible to the ultraviolet light source. Water pre-filtration is critical as water turbidity lowers UV-C penetration. Many of the better UV sterilizers have long dwell times and limit the space between the UV-C source and the inside wall of the UV sterilizer device.
Bacterial mat In industry Bacterial_mats > Uses and impact > In industry Biofilms can also be harnessed for constructive purposes. For example, many sewage treatment plants include a secondary treatment stage in which waste water passes over biofilms grown on filters, which extract and digest organic compounds. In such biofilms, bacteria are mainly responsible for removal of organic matter (BOD), while protozoa and rotifers are mainly responsible for removal of suspended solids (SS), including pathogens and other microorganisms.
CumFreq Software features CumFreq > Software features CumFreq uses the plotting position approach to estimate the cumulative frequency of each of the observed magnitudes in a data series of the variable.The computer program allows determination of the best fitting probability distribution. Alternatively it provides the user with the option to select the probability distribution to be fitted. The following probability distributions are included: normal, lognormal, logistic, loglogistic, exponential, Cauchy, Fréchet, Gumbel, Pareto, Weibull, Generalized extreme value distribution, Laplace distribution, Burr distribution (Dagum mirrored), Dagum distribution (Burr mirrored), Gompertz distribution, Student distribution and other. Another characteristic of CumFreq is that it provides the option to use two different probability distributions, one for the lower data range, and one for the higher.
Drainage equation Hooghoudt's equation Drainage_equation > Hooghoudt's equation Drainage criteria One would not want the water table to be too shallow to avoid crop yield depression nor too deep to avoid drought conditions. This is a subject of drainage research. The figure shows that a seasonal average depth of the water table shallower than 70 cm causes a yield depression The figure was made with the SegReg program for segmented regression.
Ozone Depleting Substances Ozone hole over tropics Ozone_destruction > Research history > Ozone hole over tropics Physicist Qing-Bin Lu, of the University of Waterloo, claimed to have discovered a large, all-season ozone hole in the lower stratosphere over the tropics in July 2022. However, other researchers in the field refuted this claim, stating that the research was riddled with "serious errors and unsubstantiated assertions." According to Dr Paul Young, a lead author of the 2022 WMO/UNEP Scientific Assessment of Ozone Depletion, "The author's identification of a ‘tropical ozone hole’ is down to him looking at percentage changes in ozone, rather than absolute changes, with the latter being much more relevant for damaging UV reaching the surface." Specifically, Lu's work defines "ozone hole" as "an area with O3 loss in percent larger than 25%, with respect to the undisturbed O3 value when there were no significant CFCs in the stratosphere (~ in the 1960s)" instead of the general definition of 220 Dobson units or lower. Dr Marta Abalos Alvarez has added "Ozone depletion in the tropics is nothing new and is mainly due to the acceleration of the Brewer-Dobson circulation."
Pet cloning Animal welfare Pet_cloning > Controversies > Animal welfare The mortality rate for cloned animals is higher than for those born of natural processes. This includes a discrepancy pre-birth, during birth, and after birth in survival rates and quality of life, leading to ethical concerns. Many of these discrepancies are thought to come from maternal mRNA already present in the oocyte prior to the transfer of genetic material as well as from DNA methylation, both of which contribute to the development of the animal in the womb of the surrogate. Some common issues seen with cloned animals are shortened telomeres, the repetitive end sequences of DNA whose decreasing length over the lifespan of an organism have been associated with aging; large offspring syndrome, the abnormal size of cloned individuals due to epigenetic (gene expression) changes; and methylation patterns of genetic material that are so abnormal compared to standard embryos of the species being cloned as to be incompatible with life.
Keto acid Summary Keto_acid For instance, in plants (specifically, in hemlock, pitcher plants, and fool's parsley), 5-oxo-octanoic acid is converted in enzymatic and non-enzymatic steps into the cyclic class of coniine alkaloids.When ingested sugars and carbohydrate levels are low, stored fats and proteins are the primary source of energy production. Glucogenic amino acids from proteins and/or Glycerol from Triglycerides are converted to glucose. Ketogenic amino acids can be deaminated to produce alpha keto acids and ketone bodies. Alpha keto acids are used primarily as energy for liver cells and in fatty acid synthesis, also in the liver.
Learning object Definitions Learning_object > Definitions The Institute of Electrical and Electronics Engineers (IEEE) defines a learning object as "any entity, digital or non-digital, that may be used for learning, education or training".Chiappe defined Learning Objects as: "A digital self-contained and reusable entity, with a clear educational purpose, with at least three internal and editable components: content, learning activities and elements of context. The learning objects must have an external structure of information to facilitate their identification, storage and retrieval: the metadata. "The following definitions focus on the relation between learning object and digital media. RLO-CETL, a British inter-university Learning Objects Center, defines "reusable learning objects" as "web-based interactive chunks of e-learning designed to explain a stand-alone learning objective".
Pisarenko harmonic decomposition History Pisarenko_harmonic_decomposition > History The method was first discovered in 1911 by Constantin Carathéodory, then rediscovered by Vladilen Fedorovich Pisarenko in 1973 while examining the problem of estimating the frequencies of complex signals in white noise. He found that the frequencies could be derived from the eigenvector corresponding to the minimum eigenvalue of the autocorrelation matrix.
Short-circuiting operator Reduced efficiency due to constraining optimizations Short-circuiting_operator > Possible problems > Reduced efficiency due to constraining optimizations Short-circuiting can lead to errors in branch prediction on modern central processing units (CPUs), and dramatically reduce performance. A notable example is highly optimized ray with axis aligned box intersection code in ray tracing. Some compilers can detect such cases and emit faster code, but programming language semantics may constrain such optimizations.An example of a compiler unable to optimize for such a case is Java's Hotspot VM as of 2012.
Fatigue Testing Notable fatigue tests Fatigue_Testing > Notable fatigue tests de Havilland Comet suffered a series of catastrophic failures that ultimately proved to be fatigue despite being fatigue tested. Fatigue tests on 110 Mustang wing sets were carried out to determine the scatter in fatigue life. The novel No Highway and movie No Highway in the Sky were about the fictional fatigue test of the fuselage of a passenger aircraft. Fatigue tests have also been used to grow fatigue cracks that are too small to be detected.
Tetrahedral intermediate Drug design Tetrahedral_carbonyl_addition_compound > Applications in biomedicine > Drug design A solvated ligand that binds the protein of interest is likely to exist as an equilibrium mixture of several conformers. Likewise the solvated protein also exists as several conformers in equilibrium. Formation of protein-ligand complex includes displacement of the solvent molecules that occupy the binding site of the ligand, to produce a solvated complex. Because this necessarily means that the interaction is entropically disfavored, highly favorable enthalpic contacts between the protein and the ligand must compensate for the entropic loss.
Geological structure measurement by LiDAR Summary Geological_structure_measurement_by_LiDAR These structures include folds, fault planes, size, persistence, spatial variations, and numbers of the rock discontinuities in a particular region. These discontinuity features significantly impact slope stability, causing slope failures or separating a rock mass into intact rock blocks (rockfall). Some displaced blocks along faults are signs of earthquakes.
Converter station DC equipment Converter_station > Components > DC equipment Air coils have the advantage of generating less acoustical noise than iron-core coils, they eliminate the potential environmental hazard of spilled oil, and they do not saturate under transient high current fault conditions. This part of the plant will also contain instruments for measurement of direct current and voltage. Special direct current filters are used to eliminate high frequency interference.
Synergistic enhancer (antiretroviral) Types Synergistic_enhancer_(antiretroviral) > Types It enhances ddI, and to a lesser extent AZT and ddC. One possible explanation is that HU causes cells to spend more time in the "S" phase checkpoint of cellular growth which allows ddI, AZT and ddC into the cell more. In addition HU inhibits ribonucleotide reductase, an enzyme used to break down certain proteins to form the building blocks of DNA called dNTPs.
Bias–variance tradeoff Approaches Bias–variance_tradeoff > Approaches In artificial neural networks, the variance increases and the bias decreases as the number of hidden units increase, although this classical assumption has been the subject of recent debate. Like in GLMs, regularization is typically applied. In k-nearest neighbor models, a high value of k leads to high bias and low variance (see below).
RL circuit Impulse response RL_circuit > Series circuit > Impulse response The impulse response for each voltage is the inverse Laplace transform of the corresponding transfer function. It represents the response of the circuit to an input voltage consisting of an impulse or Dirac delta function. The impulse response for the inductor voltage is h L ( t ) = δ ( t ) − R L e − t R L u ( t ) = δ ( t ) − 1 τ e − t τ u ( t ) , {\displaystyle h_{L}(t)=\delta (t)-{\frac {R}{L}}e^{-t{\frac {R}{L}}}u(t)=\delta (t)-{\frac {1}{\tau }}e^{-{\frac {t}{\tau }}}u(t)\,,} where u(t) is the Heaviside step function and τ = L/R is the time constant. Similarly, the impulse response for the resistor voltage is h R ( t ) = R L e − t R L u ( t ) = 1 τ e − t τ u ( t ) . {\displaystyle h_{R}(t)={\frac {R}{L}}e^{-t{\frac {R}{L}}}u(t)={\frac {1}{\tau }}e^{-{\frac {t}{\tau }}}u(t)\,.}
Thermal management (electronics) Heat sinks Thermal_management_(electronics) > Methodologies > Heat sinks Heat sinks are widely used in electronics and have become essential to modern microelectronics. In common use, it is a metal object brought into contact with an electronic component's hot surface—though in most cases, a thin thermal interface material mediates between the two surfaces. Microprocessors and power handling semiconductors are examples of electronics that need a heat sink to reduce their temperature through increased thermal mass and heat dissipation (primarily by conduction and convection and to a lesser extent by radiation). Heat sinks have become almost essential to modern integrated circuits like microprocessors, DSPs, GPUs, and more.
Membrane (M-Theory) General and cited references Brane_theory > General and cited references Retrieved June 7, 2018. Yau, Shing-Tung; Nadis, Steve (2010). The Shape of Inner Space: String Theory and the Geometry of the Universe's Hidden Dimensions.
History of computing Personal computers History_of_computing > Digital electronic computers > Personal computers The metal–oxide–silicon field-effect transistor (MOSFET), also known as the MOS transistor, was invented by Mohamed Atalla and Dawon Kahng at Bell Labs in 1959. It was the first truly compact transistor that could be miniaturised and mass-produced for a wide range of uses. The MOSFET made it possible to build high-density integrated circuit chips. The MOSFET is the most widely used transistor in computers, and is the fundamental building block of digital electronics.The silicon-gate MOS integrated circuit was developed by Federico Faggin at Fairchild Semiconductor in 1968.
Nonsense codon Suppressing Nonsense Mutations Nonsense_mutation > Suppressing Nonsense Mutations Nonsense-mediated mRNA decay Despite an expected tendency for premature termination codons to yield shortened polypeptide products, in fact the formation of truncated proteins does not occur often in vivo. Many organisms—including humans and lower species, such as yeast—employ a nonsense-mediated mRNA decay pathway, which degrades mRNAs containing nonsense mutations before they are able to be translated into nonfunctional polypeptides. tRNA Suppression Because nonsense mutations result in altered mRNA with a premature stop codon, one way of suppressing the damage done to the final protein's function is to alter the tRNA that reads the mRNA. These tRNA’s are termed suppressor tRNA's.
NAT traversal Techniques NAT_traversal > Techniques Various NAT traversal techniques have been developed: NAT Port Mapping Protocol (NAT-PMP) is a protocol introduced by Apple as an alternative to IGDP. Port Control Protocol (PCP) is a successor of NAT-PMP. UPnP Internet Gateway Device Protocol (UPnP IGD) is supported by many small NAT gateways in home or small office settings.
Connectionism The first wave Connectionism > The first wave Hebb contributed greatly to speculations about neural functioning, and proposed a learning principle, Hebbian learning, that is still used today. Lashley argued for distributed representations as a result of his failure to find anything like a localized engram in years of lesion experiments. Another form of connectionist model was the relational network framework developed by the linguist Sydney Lamb in the 1960s.
Burnishing (metal) Effects on sliding contact Burnishing_(metal) > Effects on sliding contact The plastic deformation associated with burnishing creates greater heat and friction than from rubbing alone. This reduces the efficiency of the machine and limits its speed. Furthermore, plastic deformation alters the form and geometry of the part.
Artistic rendering 2D Artistic_rendering > 2D This automation enabled practical application of 2D NPR to video, for the first time in the living paintings of the movie What Dreams May Come (1998). More sophisticated image abstractions techniques were developed in the early 2000s harnessing computer vision operators e.g. image salience, or segmentation operators to drive stroke placement. Around this time, machine learning began to influence image stylization algorithms notably image analogy that could learn to mimic the style of an existing artwork.
Intelligent agents Objective function Artificial_agents > Objective function Some AI systems, such as nearest-neighbor, instead of reason by analogy, these systems are not generally given goals, except to the degree that goals are implicit in their training data. Such systems can still be benchmarked if the non-goal system is framed as a system whose "goal" is to accomplish its narrow classification task.Systems that are not traditionally considered agents, such as knowledge-representation systems, are sometimes subsumed into the paradigm by framing them as agents that have a goal of (for example) answering questions as accurately as possible; the concept of an "action" is here extended to encompass the "act" of giving an answer to a question. As an additional extension, mimicry-driven systems can be framed as agents who are optimizing a "goal function" based on how closely the IA succeeds in mimicking the desired behavior.
Perl virtual machine Scope stack Perl_virtual_machine > Implementation > Stacks > Scope stack This stack stores information about the actual scope and it is used only for debugging purposes.
Simulation of production systems Disaster preparedness Simulation_of_production_systems > More examples of simulation > Disaster preparedness CADE has used a video game to prepare emergency workers for multiple types of attacks. As reported by News-Medical.Net, "The video game is the first in a series of simulations to address bioterrorism, pandemic flu, smallpox, and other disasters that emergency personnel must prepare for." Developed by a team from the University of Illinois at Chicago (UIC), the game allows learners to practice their emergency skills in a safe, controlled environment.
Eyring equation General form Eyring_equation > General form The general form of the Eyring–Polanyi equation somewhat resembles the Arrhenius equation: where k {\displaystyle k} is the rate constant, Δ G ‡ {\displaystyle \Delta G^{\ddagger }} is the Gibbs energy of activation, κ {\displaystyle \kappa } is the transmission coefficient, k B {\displaystyle k_{\mathrm {B} }} is the Boltzmann constant, T {\displaystyle T} is the temperature, and h {\displaystyle h} is the Planck constant. The transmission coefficient κ {\displaystyle \kappa } is often assumed to be equal to one as it reflects what fraction of the flux through the transition state proceeds to the product without recrossing the transition state. So, a transmission coefficient equal to one means that the fundamental no-recrossing assumption of transition state theory holds perfectly. However, κ {\displaystyle \kappa } is typically not one because (i) the reaction coordinate chosen for the process at hand is usually not perfect and (ii) many barrier-crossing processes are somewhat or even strongly diffusive in nature.
Finite difference methods The SBP-SAT method Finite_difference_scheme > The SBP-SAT method The SBP-SAT (summation by parts - simultaneous approximation term) method is a stable and accurate technique for discretizing and imposing boundary conditions of a well-posed partial differential equation using high order finite differences.The method is based on finite differences where the differentiation operators exhibit summation-by-parts properties. Typically, these operators consist of differentiation matrices with central difference stencils in the interior with carefully chosen one-sided boundary stencils designed to mimic integration-by-parts in the discrete setting. Using the SAT technique, the boundary conditions of the PDE are imposed weakly, where the boundary values are "pulled" towards the desired conditions rather than exactly fulfilled. If the tuning parameters (inherent to the SAT technique) are chosen properly, the resulting system of ODE's will exhibit similar energy behavior as the continuous PDE, i.e. the system has no non-physical energy growth. This guarantees stability if an integration scheme with a stability region that includes parts of the imaginary axis, such as the fourth order Runge-Kutta method, is used. This makes the SAT technique an attractive method of imposing boundary conditions for higher order finite difference methods, in contrast to for example the injection method, which typically will not be stable if high order differentiation operators are used.
Momentum Multiple dimensions Momentum_vector > Newtonian > Multiple dimensions For example, represents three equations: The kinetic energy equations are exceptions to the above replacement rule. The equations are still one-dimensional, but each scalar represents the magnitude of the vector, for example, Each vector equation represents three scalar equations. Often coordinates can be chosen so that only two components are needed, as in the figure. Each component can be obtained separately and the results combined to produce a vector result.A simple construction involving the center of mass frame can be used to show that if a stationary elastic sphere is struck by a moving sphere, the two will head off at right angles after the collision (as in the figure).
Computer icon Size and scalability Computer_icon > Design > Size and scalability The standard icon is generally the size of an adult thumb, enabling both easy visual recognition and use in a touchscreen device. For individual devices the display size correlates directly to the size of the screen real estate and the resolution of the display. Because they are used in multiple locations on the screen, the design must remain recognizable at the smallest size, for use in a directory tree or title bar, while retaining an attractive shape in the larger sizes. In addition to scaling, it may be necessary to remove visual details or simplify the subject between discrete sizes. Larger icons serve also as part of the accessibility features for the visually impaired on many computer systems. The width and height of the icon are the same (1:1 aspect ratio) in almost all areas of traditional use.
Tajima's D Summary Tajima's_D The randomly evolving mutations are called "neutral", while mutations under selection are "non-neutral". For example, a mutation that causes prenatal death or severe disease would be expected to be under selection. In the population as a whole, the frequency of a neutral mutation fluctuates randomly (i.e. the percentage of individuals in the population with the mutation changes from one generation to the next, and this percentage is equally likely to go up or down) through genetic drift.
Human immune system Vaccination Immune_surveillance > Manipulation in medicine > Vaccination Long-term active memory is acquired following infection by activation of B and T cells. Active immunity can also be generated artificially, through vaccination. The principle behind vaccination (also called immunization) is to introduce an antigen from a pathogen to stimulate the immune system and develop specific immunity against that particular pathogen without causing disease associated with that organism. This deliberate induction of an immune response is successful because it exploits the natural specificity of the immune system, as well as its inducibility. With infectious disease remaining one of the leading causes of death in the human population, vaccination represents the most effective manipulation of the immune system mankind has developed.Many vaccines are based on acellular components of micro-organisms, including harmless toxin components. Since many antigens derived from acellular vaccines do not strongly induce the adaptive response, most bacterial vaccines are provided with additional adjuvants that activate the antigen-presenting cells of the innate immune system and maximize immunogenicity.
Factorization homology Summary Factorization_homology In algebraic topology and category theory, factorization homology is a variant of topological chiral homology, motivated by an application to topological quantum field theory and cobordism hypothesis in particular. It was introduced by David Ayala, John Francis, and Nick Rozenblyum.
Chinese BASIC Example Chinese_BASIC > Example A in line 250. They all do the same thing—to print out the value of A on screen. This program calculates the sum of log (E) + log (E+1) + log (E+2) + ... + log (F).
Projected rotational velocity Summary Projected_rotational_velocity Thus the equator of the star can rotate at a different angular velocity than the higher latitudes. These differences in the rate of rotation within a star may have a significant role in the generation of a stellar magnetic field.In its turn, the magnetic field of a star interacts with the stellar wind. As the wind moves away from the star its angular speed decreases. The magnetic field of the star interacts with the wind, which applies a drag to the stellar rotation. As a result, angular momentum is transferred from the star to the wind, and over time this gradually slows the star's rate of rotation.
Telecommunication convergence Cellphones Media_convergence > Digital convergence > Cellphones The functions of the cellphone changes as technology converges. Because of technological advancement, a cellphone functions as more than just a phone: it can also contain an Internet connection, video players, MP3 players, gaming, and a camera. Their areas of use have increased over time, partly substituting for other devices. A mobile convergence device is one that, if connected to a keyboard, monitor, and mouse, can run applications as a desktop computer would. Convergent operating systems include the Linux operating systems Ubuntu Touch, Plasma Mobile and PureOS.Convergence can also refer to being able to run the same app across different devices and being able to develop apps for different devices (such as smartphones, TVs and desktop computers) at once, with the same code base. This can be done via Linux applications that adapt to the device they're being used on (including native apps designed for such via frameworks like Kirigami) or by the use of multi-platform frameworks like the Quasar framework that use tools such as Apache Cordova, Electron and Capacitor, which can increase the userbase, the pace and ease of development and the number of reached platforms while decreasing development costs.
Gustavus Detlef Hinrichs Summary Gustavus_Detlef_Hinrichs Gustavus Detlef Hinrichs (2 December 1836 – 14 February 1923) was a chemist and natural philosopher most widely known for his findings on periodic laws within the chemical elements.
Arithmetical transfinite recursion Summary Constructive_reverse_mathematics Reverse mathematics is a program in mathematical logic that seeks to determine which axioms are required to prove theorems of mathematics. Its defining method can briefly be described as "going backwards from the theorems to the axioms", in contrast to the ordinary mathematical practice of deriving theorems from axioms. It can be conceptualized as sculpting out necessary conditions from sufficient ones. The reverse mathematics program was foreshadowed by results in set theory such as the classical theorem that the axiom of choice and Zorn's lemma are equivalent over ZF set theory.
Business simulation Games and business simulation games Business_simulation > Games and business simulation games This process includes the kind of reflection and inquiry for which there is no time in the hectic everyday world. Thus, Senge and Lannon argue, managers learn about the long-term, systemic consequences of their actions.
Design for All (in ICT) Examples of good practice Design_for_All_(in_ICT) > Examples of good practice The emergency intercom system operates aurally and visually. Wireless tagging (e.g. RFID), facial recognition, remote controls further enhance the capabilities of a modern elevator which can be used by almost anyone. The Inclusive Design Toolkit presents examples of how Design for All principles can be implemented. Other examples of Design for All in ICT are presented in EDeAN's Education and Training Resource.
Earthquake prediction Disturbance of the daily cycle of the ionosphere Earthquake_prediction > Prediction methods > Precursors > Electromagnetic anomalies > Freund physics > Disturbance of the daily cycle of the ionosphere Tectonic stresses in the Earth's crust are claimed to cause waves of electric charges that travel to the surface of the Earth and affect the ionosphere. ULF* recordings of the daily cycle of the ionosphere indicate that the usual cycle could be disturbed a few days before a shallow strong earthquake. When the disturbance occurs, it is observed that either the D layer is lost during the day resulting to ionosphere elevation and skywave formation or the D layer appears at night resulting to lower of the ionosphere and hence absence of skywave.Science centers have developed a network of VLF transmitters and receivers on a global scale that detect changes in skywave.
Climbing harness Types Climbing_harness > Types A sit harness consists of a waist belt and two leg loops which are normally connected in the front of the hips through a permanent webbing loop called a belay loop. Belay loops are extremely strong, but nonetheless still a single point of failure that caused at least one notorious death. For rock climbing, the rope typically goes through the two "tie-in loops" that are above and below the "belay loop". The figure-eight knot is mostly used for rock climbing.
Heat pumps Performance Heat_Pump > Performance Larger values of either metric indicate better performance. When comparing the performance of heat pumps, the term performance is preferred to efficiency, with coefficient of performance (COP) being used to describe the ratio of useful heat movement per work input. An electrical resistance heater has a COP of 1.0, which is considerably lower than a well-designed heat pump which will typically be between COP of 3 to 5 with an external temperature of 10 °C and an internal temperature of 20 °C. Because the ground is a constant temperature source, a ground-source heat pump is not subjected to large temperature fluctuations, and therefore is considered the most energy-efficient type of heat pump.The "Seasonal Coefficient of Performance" (SCOP) is a measure of the aggregate energy efficiency measure over a period of one year which is dependent on regional climate. One framework for this calculation is given by the Commission Regulation (EU) No. 813/2013.A heat pump's operating performance in cooling mode is characterized in the US by either its energy efficiency ratio (EER) or seasonal energy efficiency ratio (SEER), both of which have units of BTU/(h·W) (note that 1 BTU/(h·W) = 0.293 W/W) and larger values indicate better performance.

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