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Anthracomartidae Haase, 1890
synonyms
= Promygalidae Frič, 1904
= Brachypygidae Pocock, 1911
= Coryphomartidae Petrunkevitch, 1945
= Pleomartidae Petrunkevitch, 1945
Anthracomartus Karsch, 1882
synonyms
= Brachylycosa Frič, 1904
= Cleptomartus Petrunkevitch, 1949
= Coryphomartus Petrunkevitch, 1945
= Cryptomartus ... | Trigonotarbida | Wikipedia | 496 | 5068752 | https://en.wikipedia.org/wiki/Trigonotarbida | Biology and health sciences | Prehistoric arachnids | Animals |
Anthracomartus radvanicensis (Opluštil, 1985) – Late Carboniferous, Czech Republic
Anthracomartus triangularis Petrunkevitch, 1913 – Late Carboniferous, Canada
Anthracomartus trilobitus Scudder, 1884 – Late Carboniferous, United States
Anthracomartus voelkelianus Karsch, 1882 – Late Carboniferous, Poland
Brachypyge... | Trigonotarbida | Wikipedia | 147 | 5068752 | https://en.wikipedia.org/wiki/Trigonotarbida | Biology and health sciences | Prehistoric arachnids | Animals |
Anthracosironidae Pocock, 1903
Anthracosiro Pocock, 1903
Anthracosiro fritschii Pocock, 1903 – Late Carboniferous, Europe
synonym
= Anthracosiro elongatus Waterlot, 1934
Anthracosiro woodwardi Pocock, 1903 – Late Carboniferous, Europe
synonyms
= Anthracosiro corsini Pruvost, 1926
= Anthracosiro latipes Gill, 1909
A... | Trigonotarbida | Wikipedia | 289 | 5068752 | https://en.wikipedia.org/wiki/Trigonotarbida | Biology and health sciences | Prehistoric arachnids | Animals |
Aphantomartidae Petrunkevitch, 1945
synonym
= Trigonomartidae Petrunkevitch, 1949
Alkenia Størmer, 1970
Alkenia mirabilis Størmer, 1970 - Devonian, Alken an der Mosel
Aphantomartus Pocock, 1911
synonyms
= Trigonomartus Petrunkevitch, 1913
= Phrynomartus Petrunkevitch, 1945a
Aphantomartus areolatus Pocock, 1911 – Ea... | Trigonotarbida | Wikipedia | 442 | 5068752 | https://en.wikipedia.org/wiki/Trigonotarbida | Biology and health sciences | Prehistoric arachnids | Animals |
Eophrynidae Karsch, 1882
synonym
= Hemiphrynidae Frič, 1904
Eophrynus Woodward, 1871
Eophrynus prestvicii (Buckland, 1837) – Late Carboniferous, England
Eophrynus udus Brauckmann, Koch & Kemper, 1985 – Late Carboniferous, Germany
Nyranytarbus Harvey & Selden, 1995
synonym
Hemiphrynus Frič, 1901
Nyranytarbus hofma... | Trigonotarbida | Wikipedia | 431 | 5068752 | https://en.wikipedia.org/wiki/Trigonotarbida | Biology and health sciences | Prehistoric arachnids | Animals |
Family uncertain
Aenigmatarbus Poschmann, Dunlop, Bértoux & Galtier, 2016
Aenigmatarbus rastelli Poschmann, Dunlop, Bértoux & Galtier, 2016 - Carboniferous, Graissessac, France
Namurotarbus Poschmann & Dunlop, 2010
Namurotarbus roessleri (Dunlop & Brauckmann, 2006) - Carboniferous, Hagen-Vorhalle
synonyms
= Archaeomar... | Trigonotarbida | Wikipedia | 380 | 5068752 | https://en.wikipedia.org/wiki/Trigonotarbida | Biology and health sciences | Prehistoric arachnids | Animals |
Genital herpes is a herpes infection of the genitals caused by the herpes simplex virus (HSV). Most people either have no or mild symptoms and thus do not know they are infected. When symptoms do occur, they typically include small blisters that break open to form painful ulcers. Flu-like symptoms, such as fever, achin... | Genital herpes | Wikipedia | 495 | 5069414 | https://en.wikipedia.org/wiki/Genital%20herpes | Biology and health sciences | Viral diseases | Health |
Other common symptoms include pain, itching, and burning. Less frequent, yet still common, symptoms include discharge from the penis or vagina, fever, headache, muscle pain (myalgia), swollen and enlarged lymph nodes and malaise. Women often experience additional symptoms that include painful urination (dysuria) and ce... | Genital herpes | Wikipedia | 421 | 5069414 | https://en.wikipedia.org/wiki/Genital%20herpes | Biology and health sciences | Viral diseases | Health |
Transmission
Genital herpes can be spread by viral shedding prior to and following the formation of ulcers. The risk of spread between a couple is about 7.5% over a year (for unprotected sex). The likelihood of transferring genital herpes from one person to another is decreased by external condom use by 50%, by interna... | Genital herpes | Wikipedia | 460 | 5069414 | https://en.wikipedia.org/wiki/Genital%20herpes | Biology and health sciences | Viral diseases | Health |
False negative test results may occur if the test is performed late in the course of the illness or if the test sample is not appropriately acquired. Testing people for HSV when they are asymptomatic is not recommended due to the high false-positivity rate. A false positive test may cause relationship difficulties.
Ge... | Genital herpes | Wikipedia | 442 | 5069414 | https://en.wikipedia.org/wiki/Genital%20herpes | Biology and health sciences | Viral diseases | Health |
There is no cure for the disease. Skin lesions disappear without treatment within a few weeks, but treatment accelerates the healing of lesions, reduces symptoms, and helps prevent or reduce recurrent outbreaks of the disease.
Antiviral medications provide clinical benefits to those who are symptomatic and is the prima... | Genital herpes | Wikipedia | 406 | 5069414 | https://en.wikipedia.org/wiki/Genital%20herpes | Biology and health sciences | Viral diseases | Health |
The first time an individual experiences genital herpes, they may have prolonged clinical illness with severe genital ulceration. Furthermore, for those who have mild clinical symptoms initially may experience severe recurrent infections later. Typical recommended regimens for first clinical episodes of genital herpes ... | Genital herpes | Wikipedia | 458 | 5069414 | https://en.wikipedia.org/wiki/Genital%20herpes | Biology and health sciences | Viral diseases | Health |
Epidemiology
About 16 percent of Americans between the ages of 14 and 49 are infected with genital herpes, making it one of the most common sexually transmitted infections. More than 85% of those with HSV-2 are unaware of their infection. Approximately 776,000 people in the United States get new herpes infections ever... | Genital herpes | Wikipedia | 297 | 5069414 | https://en.wikipedia.org/wiki/Genital%20herpes | Biology and health sciences | Viral diseases | Health |
The human immunodeficiency virus (HIV) is a retrovirus that attacks the immune system. It is a preventable disease. It can be managed with treatment and become a manageable chronic health condition. While there is no cure or vaccine for HIV, antiretroviral treatment can slow the course of the disease and enable people ... | HIV/AIDS | Wikipedia | 400 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
HIV is spread primarily by unprotected sex (including anal and vaginal sex), contaminated hypodermic needles or blood transfusions, and from mother to child during pregnancy, delivery, or breastfeeding. Some bodily fluids, such as saliva, sweat, and tears, do not transmit the virus. Oral sex has little risk of transmit... | HIV/AIDS | Wikipedia | 489 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
The initial period following infection with HIV is called acute HIV, primary HIV or acute retroviral syndrome. Many individuals develop an illness like influenza, mononucleosis or glandular fever 2–4 weeks after exposure while others have no significant symptoms. Symptoms occur in 40–90% of cases and most commonly incl... | HIV/AIDS | Wikipedia | 403 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
Although most HIV-1 infected individuals have a detectable viral load and in the absence of treatment will eventually progress to AIDS, a small proportion (about 5%) retain high levels of CD4+ T cells (T helper cells) without antiretroviral therapy for more than five years. These individuals are classified as "HIV cont... | HIV/AIDS | Wikipedia | 499 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
Additionally, people with AIDS frequently have systemic symptoms such as prolonged fevers, sweats (particularly at night), swollen lymph nodes, chills, weakness, and unintended weight loss. Diarrhea is another common symptom, present in about 90% of people with AIDS. They can also be affected by diverse psychiatric and... | HIV/AIDS | Wikipedia | 409 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
With regard to unprotected heterosexual contacts, estimates of the risk of HIV transmission per sexual act appear to be four to ten times higher in low-income countries than in high-income countries. In low-income countries, the risk of female-to-male transmission is estimated as 0.38% per act, and of male-to-female tr... | HIV/AIDS | Wikipedia | 481 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
The second-most frequent mode of HIV transmission is via blood and blood products. Blood-borne transmission can be through needle-sharing during intravenous drug use, needle-stick injury, transfusion of contaminated blood or blood product, or medical injections with unsterilized equipment. The risk from sharing a needl... | HIV/AIDS | Wikipedia | 510 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
HIV can be transmitted from mother to child during pregnancy, during delivery, or through breast milk, resulting in the baby also contracting HIV. As of 2008, vertical transmission accounted for about 90% of cases of HIV in children. In the absence of treatment, the risk of transmission before or during birth is around... | HIV/AIDS | Wikipedia | 490 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
HIV is now known to spread between CD4+ T cells by two parallel routes: cell-free spread and cell-to-cell spread, i.e. it employs hybrid spreading mechanisms. In the cell-free spread, virus particles bud from an infected T cell, enter the blood/extracellular fluid and then infect another T cell following a chance encou... | HIV/AIDS | Wikipedia | 410 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
Ultimately, HIV causes AIDS by depleting CD4+ T cells. This weakens the immune system and allows opportunistic infections. T cells are essential to the immune response and without them, the body cannot fight infections or kill cancerous cells. The mechanism of CD4+ T cell depletion differs in the acute and chronic phas... | HIV/AIDS | Wikipedia | 466 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
HIV/AIDS is diagnosed via laboratory testing and then staged based on the presence of certain signs or symptoms. HIV screening is recommended by the United States Preventive Services Task Force for all people 15 years to 65 years of age, including all pregnant women. Additionally, testing is recommended for those at hi... | HIV/AIDS | Wikipedia | 425 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
The World Health Organization first proposed a definition for AIDS in 1986. Since then, the WHO classification has been updated and expanded several times, with the most recent version being published in 2007. The WHO system uses the following categories:
Primary HIV infection: May be either asymptomatic or associated... | HIV/AIDS | Wikipedia | 458 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
Consistent condom use reduces the risk of HIV transmission by approximately 80% over the long term. When condoms are used consistently by a couple in which one person is infected, the rate of HIV infection is less than 1% per year. There is some evidence to suggest that female condoms may provide an equivalent level of... | HIV/AIDS | Wikipedia | 376 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
Pre-exposure
Antiretroviral treatment among people with HIV whose CD4 count ≤ 550 cells/μL is a very effective way to prevent HIV infection of their partner (a strategy known as treatment as prevention, or TASP). TASP is associated with a 10- to 20-fold reduction in transmission risk. Pre-exposure prophylaxis for HIV ... | HIV/AIDS | Wikipedia | 441 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
Programs to prevent the vertical transmission of HIV (from mothers to children) can reduce rates of transmission by 92–99%. This primarily involves the use of a combination of antiviral medications during pregnancy and after birth in the infant, and potentially includes bottle feeding rather than breastfeeding. If repl... | HIV/AIDS | Wikipedia | 349 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
Current ART options are combinations (or "cocktails") consisting of at least three medications belonging to at least two types, or "classes", of antiretroviral agents. There are eight classes of antiretroviral agents (ARVs), and over 30 individual drugs: nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs), n... | HIV/AIDS | Wikipedia | 451 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
Benefits of treatment include a decreased risk of progression to AIDS and a decreased risk of death. In the developing world, treatment also improves physical and mental health. With treatment, there is a 70% reduced risk of acquiring tuberculosis. Additional benefits include a decreased risk of transmission of the dis... | HIV/AIDS | Wikipedia | 462 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
The combination of Rekambys and Vocabria injection is intended for maintenance treatment of adults who have undetectable HIV levels in the blood (viral load less than 50 copies/mL) with their current ARV treatment, and when the virus has not developed resistance to a certain class of anti-HIV medicines called non-nucle... | HIV/AIDS | Wikipedia | 504 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
The World Health Organization (WHO) has issued recommendations regarding nutrient requirements in HIV/AIDS. A generally healthy diet is promoted. Dietary intake of micronutrients at RDA levels by HIV-infected adults is recommended by the WHO; higher intake of vitamin A, zinc, and iron can produce adverse effects in HIV... | HIV/AIDS | Wikipedia | 321 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
HIV/AIDS has become a chronic rather than an acutely fatal disease in many areas of the world. Prognosis varies between people, and both the CD4 count and viral load are useful for predicted outcomes. Without treatment, average survival time after infection with HIV is estimated to be 9 to 11 years, depending on the HI... | HIV/AIDS | Wikipedia | 449 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
Even with anti-retroviral treatment, over the long term HIV-infected people may experience neurocognitive disorders, osteoporosis, neuropathy, cancers, nephropathy, and cardiovascular disease. Some conditions, such as lipodystrophy, may be caused both by HIV and its treatment.
Epidemiology
HIV/AIDS is considered a g... | HIV/AIDS | Wikipedia | 415 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
At the end of 2019, United States indicated that approximately 1.2 million people aged ≥13 years were living with HIV, resulting in about 18,500 deaths in 2020. There were 34,800 estimated new infections in the US in 2019, 53% of which were in the southern region of the country. In addition to geographic location, sign... | HIV/AIDS | Wikipedia | 472 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
In the early days, the CDC did not have an official name for the disease, often referring to it by way of diseases associated with it, such as lymphadenopathy, the disease after which the discoverers of HIV originally named the virus. They also used Kaposi's sarcoma and opportunistic infections, the name by which a tas... | HIV/AIDS | Wikipedia | 445 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
Both HIV-1 and HIV-2 are believed to have originated in non-human primates in West-central Africa and were transferred to humans in the early 20th century. HIV-1 appears to have originated in southern Cameroon through the evolution of SIV(cpz), a simian immunodeficiency virus (SIV) that infects wild chimpanzees (HIV-1 ... | HIV/AIDS | Wikipedia | 357 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
Specific proposed high-risk transmission channels, allowing the virus to adapt to humans and spread throughout society, depend on the proposed timing of the animal-to-human crossing. Genetic studies of the virus suggest that the most recent common ancestor of the HIV-1 M group dates back to 1910. Proponents of this da... | HIV/AIDS | Wikipedia | 387 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
The earliest retrospectively described case of AIDS is believed to have been in Norway beginning in 1966, that of Arvid Noe. In July 1960, in the wake of Congo's independence, the United Nations recruited Francophone experts and technicians from all over the world to assist in filling administrative gaps left by Belgiu... | HIV/AIDS | Wikipedia | 509 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
Often, AIDS stigma is expressed in conjunction with one or more other stigmas, particularly those associated with homosexuality, bisexuality, promiscuity, prostitution, and intravenous drug use.
In many developed countries, there is an association between AIDS and homosexuality or bisexuality, and this association is ... | HIV/AIDS | Wikipedia | 434 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
Returning to work after beginning treatment for HIV/AIDS is difficult, and affected people often work less than the average worker. Unemployment in people with HIV/AIDS also is associated with suicidal ideation, memory problems, and social isolation. Employment increases self-esteem, sense of dignity, confidence, and q... | HIV/AIDS | Wikipedia | 478 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
One of the first high-profile cases of AIDS was the American gay actor Rock Hudson. He had been diagnosed during 1984, announced that he had had the virus on July 25, 1985, and died a few months later on October 2, 1985. Another notable British casualty of AIDS that year was Nicholas Eden, a gay politician and son of f... | HIV/AIDS | Wikipedia | 459 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
There are many misconceptions about HIV and AIDS. Three misconceptions are that AIDS can spread through casual contact, that sexual intercourse with a virgin will cure AIDS, and that HIV can infect only gay men and drug users. In 2014, some among the British public wrongly thought one could get HIV from kissing (16%), ... | HIV/AIDS | Wikipedia | 504 | 5069516 | https://en.wikipedia.org/wiki/HIV/AIDS | Biology and health sciences | Illness and injury | null |
Dynamic Demand is the name of a semi-passive technology to support demand response by adjusting the load demand on an electrical power grid. It is also the name of an independent not-for-profit organization in the UK supported by a charitable grant from the Esmée Fairbairn Foundation, dedicated to promoting this techno... | Dynamic demand (electric power) | Wikipedia | 484 | 5069898 | https://en.wikipedia.org/wiki/Dynamic%20demand%20%28electric%20power%29 | Technology | Electricity transmission and distribution | null |
This spinning reserve is a significant expense to the power utilities as often fuel must be burned or potential power sales lost to maintain it. The kind of generation used for fast response is usually fossil fuel powered which produces emissions of between 0.48 and 1.3 tonnes of CO2 equivalent for every megawatt hour ... | Dynamic demand (electric power) | Wikipedia | 425 | 5069898 | https://en.wikipedia.org/wiki/Dynamic%20demand%20%28electric%20power%29 | Technology | Electricity transmission and distribution | null |
Another vital balancing service is ‘fast reserve’ which is the use of standby plant to replace possible lost generation (e.g. due to a failed power generator or lost power line). By shedding load quickly while the running generators spin up, then switching back in to bring the frequency back to standard, dynamic contro... | Dynamic demand (electric power) | Wikipedia | 394 | 5069898 | https://en.wikipedia.org/wiki/Dynamic%20demand%20%28electric%20power%29 | Technology | Electricity transmission and distribution | null |
The national grid in the UK already is a massive user of this technology at an industrial scale - up to 2GW of load can be lost instantaneously by frequency sensitive relays switching off steelworks etc., which is matched over a 20-minute cycle by up to 2GW of quite small emergency diesel generators. For a complete des... | Dynamic demand (electric power) | Wikipedia | 306 | 5069898 | https://en.wikipedia.org/wiki/Dynamic%20demand%20%28electric%20power%29 | Technology | Electricity transmission and distribution | null |
A molecular model is a physical model of an atomistic system that represents molecules and their processes. They play an important role in understanding chemistry and generating and testing hypotheses. The creation of mathematical models of molecular properties and behavior is referred to as molecular modeling, and the... | Molecular model | Wikipedia | 481 | 5072278 | https://en.wikipedia.org/wiki/Molecular%20model | Physical sciences | Substance | Chemistry |
Jacobus Henricus van 't Hoff and Joseph Le Bel introduced the concept of chemistry in three dimensions of space, that is, stereochemistry. Van 't Hoff built tetrahedral molecules representing the three-dimensional properties of carbon.
Models based on spheres
Repeating units will help to show how easy it is and clea... | Molecular model | Wikipedia | 471 | 5072278 | https://en.wikipedia.org/wiki/Molecular%20model | Physical sciences | Substance | Chemistry |
However, most molecules require holes at other angles and specialist companies manufacture kits and bespoke models. Besides tetrahedral, trigonal and octahedral holes, there were all-purpose balls with 24 holes. These models allowed rotation about the single rod bonds, which could be both an advantage (showing molecula... | Molecular model | Wikipedia | 420 | 5072278 | https://en.wikipedia.org/wiki/Molecular%20model | Physical sciences | Substance | Chemistry |
A good example of composite models is the Nicholson approach, widely used from the late 1970s for building models of biological macromolecules. The components are primarily amino acids and nucleic acids with preformed residues representing groups of atoms. Many of these atoms are directly moulded into the template, and... | Molecular model | Wikipedia | 392 | 5072278 | https://en.wikipedia.org/wiki/Molecular%20model | Physical sciences | Substance | Chemistry |
Computational Models
Computers can also model molecules mathematically. Programs such as Avogadro can run on typical desktops and can predict bond lengths and angles, molecular polarity and charge distribution, and even quantum mechanical properties such as absorption and emission spectra. However, these sorts of prog... | Molecular model | Wikipedia | 510 | 5072278 | https://en.wikipedia.org/wiki/Molecular%20model | Physical sciences | Substance | Chemistry |
Painite is a very rare borate mineral. It was first found in Myanmar by British mineralogist and gem dealer Arthur C.D. Pain who misidentified it as ruby, until it was discovered as a new gemstone in the 1950s. When it was confirmed as a new mineral species, the mineral was named after him.
The chemical makeup of pai... | Painite | Wikipedia | 269 | 2003525 | https://en.wikipedia.org/wiki/Painite | Physical sciences | Minerals | Earth science |
An ohmic contact is a non-rectifying electrical junction: a junction between two conductors that has a linear current–voltage (I–V) curve as with Ohm's law. Low-resistance ohmic contacts are used to allow charge to flow easily in both directions between the two conductors, without blocking due to rectification or exces... | Ohmic contact | Wikipedia | 484 | 3744388 | https://en.wikipedia.org/wiki/Ohmic%20contact | Physical sciences | Electrical circuits | Physics |
The Schottky barrier height between a metal and semiconductor is naively predicted by the Schottky–Mott rule to be proportional to the difference of the metal-vacuum work function and the semiconductor-vacuum electron affinity. In practice, most metal–semiconductor interfaces do not follow this rule to the predicted de... | Ohmic contact | Wikipedia | 373 | 3744388 | https://en.wikipedia.org/wiki/Ohmic%20contact | Physical sciences | Electrical circuits | Physics |
The fabrication of the ohmic contacts is a much-studied part of materials engineering that nonetheless remains something of an art. The reproducible, reliable fabrication of contacts relies on extreme cleanliness of the semiconductor surface. Since a native oxide rapidly forms on the surface of silicon, for example... | Ohmic contact | Wikipedia | 444 | 3744388 | https://en.wikipedia.org/wiki/Ohmic%20contact | Physical sciences | Electrical circuits | Physics |
Aluminum was originally the most important contact metal for silicon which was used with either the n-type or p-type semiconductor. As with other reactive metals, Al contributes to contact formation by consuming oxygen from native silicon-dioxide residue. Pure aluminum did react with the silicon, so it was replaced b... | Ohmic contact | Wikipedia | 395 | 3744388 | https://en.wikipedia.org/wiki/Ohmic%20contact | Physical sciences | Electrical circuits | Physics |
The RC time constant associated with contact resistance can limit the frequency response of devices. The charging and discharging of the leads resistance is a major cause of power dissipation in high-clock-rate digital electronics. Contact resistance causes power dissipation by Joule heating in low-frequency and analog... | Ohmic contact | Wikipedia | 118 | 3744388 | https://en.wikipedia.org/wiki/Ohmic%20contact | Physical sciences | Electrical circuits | Physics |
In computer science and computer engineering, computer architecture is a description of the structure of a computer system made from component parts. It can sometimes be a high-level description that ignores details of the implementation. At a more detailed level, the description may include the instruction set archite... | Computer architecture | Wikipedia | 478 | 25652303 | https://en.wikipedia.org/wiki/Computer%20architecture | Technology | Computer science | null |
The earliest computer architectures were designed on paper and then directly built into the final hardware form.
Later, computer architecture prototypes were physically built in the form of a transistor–transistor logic (TTL) computer—such as the prototypes of the 6800 and the PA-RISC—tested, and tweaked, before commit... | Computer architecture | Wikipedia | 282 | 25652303 | https://en.wikipedia.org/wiki/Computer%20architecture | Technology | Computer science | null |
There are other technologies in computer architecture. The following technologies are used in bigger companies like Intel, and were estimated in 2002 to count for 1% of all of computer architecture:
Macroarchitecture: architectural layers more abstract than microarchitecture
Assembly instruction set architecture: A s... | Computer architecture | Wikipedia | 391 | 25652303 | https://en.wikipedia.org/wiki/Computer%20architecture | Technology | Computer science | null |
Definition
Computer architecture is concerned with balancing the performance, efficiency, cost, and reliability of a computer system. The case of instruction set architecture can be used to illustrate the balance of these competing factors. More complex instruction sets enable programmers to write more space efficient ... | Computer architecture | Wikipedia | 415 | 25652303 | https://en.wikipedia.org/wiki/Computer%20architecture | Technology | Computer science | null |
ISAs vary in quality and completeness. A good ISA compromises between programmer convenience (how easy the code is to understand), size of the code (how much code is required to do a specific action), cost of the computer to interpret the instructions (more complexity means more hardware needed to decode and execute th... | Computer architecture | Wikipedia | 319 | 25652303 | https://en.wikipedia.org/wiki/Computer%20architecture | Technology | Computer science | null |
Implementation
Once an instruction set and microarchitecture have been designed, a practical machine must be developed. This design process is called the implementation. Implementation is usually not considered architectural design, but rather hardware design engineering. Implementation can be further broken down into ... | Computer architecture | Wikipedia | 476 | 25652303 | https://en.wikipedia.org/wiki/Computer%20architecture | Technology | Computer science | null |
Counting machine-language instructions would be misleading because they can do varying amounts of work in different ISAs. The "instruction" in the standard measurements is not a count of the ISA's machine-language instructions, but a unit of measurement, usually based on the speed of the VAX computer architecture.
Man... | Computer architecture | Wikipedia | 498 | 25652303 | https://en.wikipedia.org/wiki/Computer%20architecture | Technology | Computer science | null |
Modern circuits have less power required per transistor as the number of transistors per chip grows. This is because each transistor that is put in a new chip requires its own power supply and requires new pathways to be built to power it. However, the number of transistors per chip is starting to increase at a slower ... | Computer architecture | Wikipedia | 322 | 25652303 | https://en.wikipedia.org/wiki/Computer%20architecture | Technology | Computer science | null |
In chemistry, the mass concentration (or ) is defined as the mass of a constituent divided by the volume of the mixture .
For a pure chemical the mass concentration equals its density (mass divided by volume); thus the mass concentration of a component in a mixture can be called the density of a component in a mixtu... | Mass concentration (chemistry) | Wikipedia | 381 | 25658445 | https://en.wikipedia.org/wiki/Mass%20concentration%20%28chemistry%29 | Physical sciences | Mixture | Chemistry |
In biology and medicine, the "%" symbol is widely used in a misnomer sense to denote mass concentration, also called "mass/volume percentage". A solution with 1 g of solute dissolved in a final volume of 100 mL of solution would be labeled as "1%" or "1% m/v" (mass/volume). The common names of intravenous sugar solutio... | Mass concentration (chemistry) | Wikipedia | 442 | 25658445 | https://en.wikipedia.org/wiki/Mass%20concentration%20%28chemistry%29 | Physical sciences | Mixture | Chemistry |
Although there are examples to the contrary, it should be stressed that the commonly used "units" of % w/v are grams per millilitre (g/mL). 1% m/v solutions are sometimes thought of as being gram/100 mL but this detracts from the fact that % m/v is g/mL; 1g of water has a volume of approximately 1 mL (at standard temp... | Mass concentration (chemistry) | Wikipedia | 448 | 25658445 | https://en.wikipedia.org/wiki/Mass%20concentration%20%28chemistry%29 | Physical sciences | Mixture | Chemistry |
A cobble (sometimes a cobblestone) is a clast of rock defined on the Udden–Wentworth scale as having a particle size of , larger than a pebble and smaller than a boulder. Other scales define a cobble's size differently. A rock made predominantly of cobbles is termed a conglomerate. Cobblestone is a building material ba... | Cobble (geology) | Wikipedia | 416 | 31352816 | https://en.wikipedia.org/wiki/Cobble%20%28geology%29 | Physical sciences | Sedimentology | Earth science |
Various attempts have been made to refine the Udden–Wentworth scale, including its definition of cobbles. In 1968, D. J. Doeglas proposed subdividing the cobble designation into two fractions, small cobbles (for particles with diameters from ) and large cobbles (for particles with diameters from ). A 1999 paper by Tere... | Cobble (geology) | Wikipedia | 428 | 31352816 | https://en.wikipedia.org/wiki/Cobble%20%28geology%29 | Physical sciences | Sedimentology | Earth science |
The Mexico City Metro () is a rapid transit system that serves the metropolitan area of Mexico City, including some municipalities in the State of Mexico. Operated by the Sistema de Transporte Colectivo (STC), it is the second largest metro system in North America after the New York City Subway.
The inaugural STC Metr... | Mexico City Metro | Wikipedia | 386 | 891641 | https://en.wikipedia.org/wiki/Mexico%20City%20Metro | Technology | Americas | null |
The principal promoter of the construction of the Mexico City Metro was engineer Bernardo Quintana, who was in charge of the construction company Ingenieros Civiles y Asociados (Civil Engineers and Associates). He carried out a series of studies that resulted in a draft plan which would ultimately lead to the construct... | Mexico City Metro | Wikipedia | 499 | 891641 | https://en.wikipedia.org/wiki/Mexico%20City%20Metro | Technology | Americas | null |
Second stage (1977–1982)
No further progress was reached during President Luis Echeverría's government, but during José López Portillo's administration, a second stage began. The Comisión Ejecutiva del Metro (Executive Technical Commission of Mexico City Metro) was created in order to be in charge of expanding the STC... | Mexico City Metro | Wikipedia | 486 | 891641 | https://en.wikipedia.org/wiki/Mexico%20City%20Metro | Technology | Americas | null |
On the day of the quake, the Metro stopped service and completely shut down for fear of electrocution. This caused people to get out of the tunnels from wherever they were and onto the street to try to get where they were going. At the time, the Metro had 101 stations, with 32 closed to the public in the weeks after th... | Mexico City Metro | Wikipedia | 450 | 891641 | https://en.wikipedia.org/wiki/Mexico%20City%20Metro | Technology | Americas | null |
The draft for Line 8 planned a correspondencia (transfer station) in Zócalo, namely the exact center of the city, but it was canceled due to possible damage to the colonial buildings and the Aztec ruins, so it was replanned and now it runs from Garibaldi, which is still downtown, to Constitución de 1917 in the southeas... | Mexico City Metro | Wikipedia | 494 | 891641 | https://en.wikipedia.org/wiki/Mexico%20City%20Metro | Technology | Americas | null |
In the book Los hombres del Metro, the original planning of Line 12 is described; although it was to begin at Mixcoac as it does today, Atlalilco and Constitución de 1917 stations of Line 8 were to be part of Line 12. The same map shows that Line 8 would have reached the Villa Coapa area and that it would not have had ... | Mexico City Metro | Wikipedia | 502 | 891641 | https://en.wikipedia.org/wiki/Mexico%20City%20Metro | Technology | Americas | null |
Cultural references
The Metro has figured in Mexico's cultural history, as the inspiration for a musical composition for strings, "Metro Chabacano" and Rodrigo "Rockdrigo" González's 1982 song, "Metro Balderas". It was also a filming location for the 1990 Hollywood movie Total Recall. Public intellectual Carlos Monsiv... | Mexico City Metro | Wikipedia | 421 | 891641 | https://en.wikipedia.org/wiki/Mexico%20City%20Metro | Technology | Americas | null |
The year 1987 saw the opening of the Lázaro Cárdenas station. In 1988, Aquiles Sedán honors the first martyr of the Revolution. In 1994, Constitución de 1917 opened, as did Garibaldi, named after the grandson of Italian fighter for independence, Giuseppe Garibaldi. The grandson had been a participant in the Mexican Rev... | Mexico City Metro | Wikipedia | 461 | 891641 | https://en.wikipedia.org/wiki/Mexico%20City%20Metro | Technology | Americas | null |
The logos' background colors reflect those of the line the station serves. Stations serving two or more lines show the respective colors of each line in diagonal stripes, as in Salto del Agua. This system was adopted for the Guadalajara and Monterrey metros, and for the Mexico City Metrobús. Although logos are no longe... | Mexico City Metro | Wikipedia | 466 | 891641 | https://en.wikipedia.org/wiki/Mexico%20City%20Metro | Technology | Americas | null |
Another commuter rail, Tren Interurbano de Pasajeros Toluca-Valle de México is estimated to be completed in 2023. This line will connect Observatorio station in Mexico City with Toluca.
Fares and pay systems
Previously, a single ticket of MXN $5.00, allowed a rider one trip anywhere within the system with unlimited tr... | Mexico City Metro | Wikipedia | 411 | 891641 | https://en.wikipedia.org/wiki/Mexico%20City%20Metro | Technology | Americas | null |
In an attempt to modernize public transport, in October 2012, the Mexico City government implemented the use of a prepaid fare card, or stored-value card, called Tarjeta DF (Tarjeta del Distrito Federal, literally Federal District Card) as a payment method for STC Metro, Metrobús and the city's trolleybus and light rai... | Mexico City Metro | Wikipedia | 497 | 891641 | https://en.wikipedia.org/wiki/Mexico%20City%20Metro | Technology | Americas | null |
From May 2024, Line 1 will receive 29 new rubber-tired trains manufactured by CRRC Zhuzhou Locomotive in China, replacing earlier rolling stock. This is in line with ongoing upgrading works for Line 1, including the installation of CBTC.
Gallery
Major incidents
On 20 October 1975, two trains crashed in Viaducto stat... | Mexico City Metro | Wikipedia | 481 | 891641 | https://en.wikipedia.org/wiki/Mexico%20City%20Metro | Technology | Americas | null |
On 7 January 2023 at 09:16 local time, two trains collided between Potrero and La Raza stations on Line 3, killing one and injuring 57. In addition to other minor events, city officials said that this accident was a result of sabotage to the Fourth Transformation platform to affect the image of Claudia Sheinbaum, then ... | Mexico City Metro | Wikipedia | 84 | 891641 | https://en.wikipedia.org/wiki/Mexico%20City%20Metro | Technology | Americas | null |
Anaerobic exercise is a type of exercise that breaks down glucose in the body without using oxygen; anaerobic means "without oxygen". This type of exercise leads to a buildup of lactic acid.
In practical terms, this means that anaerobic exercise is more intense, but shorter in duration than aerobic exercise.
The bioc... | Anaerobic exercise | Wikipedia | 463 | 892484 | https://en.wikipedia.org/wiki/Anaerobic%20exercise | Biology and health sciences | Physical fitness | Health |
High energy phosphates are stored in limited quantities within muscle cells. Anaerobic glycolysis exclusively uses glucose (and glycogen) as a fuel in the absence of oxygen, or more specifically, when ATP is needed at rates that exceed those provided by aerobic metabolism. The consequence of such rapid glucose breakdow... | Anaerobic exercise | Wikipedia | 353 | 892484 | https://en.wikipedia.org/wiki/Anaerobic%20exercise | Biology and health sciences | Physical fitness | Health |
Dicynodontia is an extinct clade of anomodonts, an extinct type of non-mammalian therapsid. Dicynodonts were herbivores that typically bore a pair of tusks, hence their name, which means 'two dog tooth'. Members of the group possessed a horny, typically toothless beak, unique amongst all synapsids. Dicynodonts first ap... | Dicynodontia | Wikipedia | 459 | 892541 | https://en.wikipedia.org/wiki/Dicynodontia | Biology and health sciences | Proto-mammals | Animals |
The body is short, strong and barrel-shaped, with strong limbs. In large genera (such as Dinodontosaurus) the hindlimbs were held erect, but the forelimbs bent at the elbow. Both the pectoral girdle and the ilium are large and strong. The tail is short.
Pentasauropus dicynodont tracks suggest that dicynodonts had fles... | Dicynodontia | Wikipedia | 385 | 892541 | https://en.wikipedia.org/wiki/Dicynodontia | Biology and health sciences | Proto-mammals | Animals |
Dicynodonts have been known to science since the mid-1800s. The South African geologist Andrew Geddes Bain gave the first description of dicynodonts in 1845. At the time, Bain was a supervisor for the construction of military roads under the Corps of Royal Engineers and had found many reptilian fossils during his surve... | Dicynodontia | Wikipedia | 401 | 892541 | https://en.wikipedia.org/wiki/Dicynodontia | Biology and health sciences | Proto-mammals | Animals |
Only four lineages are known to have survived the Great Dying; the first three represented with a single genus each: Myosaurus, Kombuisia, and Lystrosaurus, the latter being the most common and widespread herbivores of the Induan (earliest Triassic). None of these survived long into the Triassic. The fourth group was t... | Dicynodontia | Wikipedia | 444 | 892541 | https://en.wikipedia.org/wiki/Dicynodontia | Biology and health sciences | Proto-mammals | Animals |
Taxonomy
Dicynodontia was originally named by the English paleontologist Richard Owen. It was erected as a family of the order Anomodontia and included the genera Dicynodon and Ptychognathus. Other groups of Anomodontia included Gnathodontia, which included Rhynchosaurus (now known to be an archosauromorph) and Cryptod... | Dicynodontia | Wikipedia | 512 | 892541 | https://en.wikipedia.org/wiki/Dicynodontia | Biology and health sciences | Proto-mammals | Animals |
Current classification
Dicynodontia
Brachyprosopus
Colobodectes
Eodicynodon
Lanthanostegus
Nyaphulia
Endothiodontia
Abajudon
Endothiodon
Niassodon
Eumantellidae
Pristerodon
Pylaecephalidae
Diictodon
Eosimops
Prosictodon
Robertia
Therochelonia
Emydopoidea
Digalodon
Rastodon
Cistecephalidae
Cistecephalus
Cistecephaloide... | Dicynodontia | Wikipedia | 482 | 892541 | https://en.wikipedia.org/wiki/Dicynodontia | Biology and health sciences | Proto-mammals | Animals |
South African geomyth
A horned serpent cave art is known from the La Belle France cave in South Africa, often conflated with the Dingonek. It may be based on dicynodont fossils. | Dicynodontia | Wikipedia | 44 | 892541 | https://en.wikipedia.org/wiki/Dicynodontia | Biology and health sciences | Proto-mammals | Animals |
Placerias (meaning 'broad body') is an extinct genus of dicynodonts that lived during the Carnian to the Norian age of the Triassic Period (230–215 million years ago). Placerias belongs to a group of dicynodonts called Kannemeyeriiformes, which was the last known group of dicynodonts before the taxon became extinct at ... | Placerias | Wikipedia | 421 | 892554 | https://en.wikipedia.org/wiki/Placerias | Biology and health sciences | Proto-mammals | Animals |
Eurypterus ( ) is an extinct genus of eurypterid, a group of organisms commonly called "sea scorpions". The genus lived during the Silurian period, from around 432 to 418 million years ago. Eurypterus is by far the most well-studied and well-known eurypterid. Eurypterus fossil specimens probably represent more than 95%... | Eurypterus | Wikipedia | 363 | 892600 | https://en.wikipedia.org/wiki/Eurypterus | Biology and health sciences | Fossil arthropods | Animals |
However, De Kay thought Eurypterus was a branchiopod (a group of crustaceans which include fairy shrimps and water fleas). Soon after, Eurypterus lacustris was also discovered in New York in 1835 by the paleontologist Richard Harlan. Another species was discovered in Estonia in 1858 by Jan Nieszkowski. He considered it... | Eurypterus | Wikipedia | 488 | 892600 | https://en.wikipedia.org/wiki/Eurypterus | Biology and health sciences | Fossil arthropods | Animals |
Eurypterus fossils often occur in similar sizes in a given area. This may be a result of the fossils being "sorted" into windrows as they were being deposited in shallow waters by storms and wave action.
The Eurypterus body is broadly divided into two parts: the prosoma and the opisthosoma (in turn divided into the me... | Eurypterus | Wikipedia | 501 | 892600 | https://en.wikipedia.org/wiki/Eurypterus | Biology and health sciences | Fossil arthropods | Animals |
Based on the width and structure of each segment, they can be divided into the broad preabdomen (segments 1 to 7) and the narrow postabdomen (segments 8 to 12). The preabdomen is the broader segments of the anterior portion of the ophisthosoma while the postabdomen are the last five segments of the Eurypterus body. Eac... | Eurypterus | Wikipedia | 453 | 892600 | https://en.wikipedia.org/wiki/Eurypterus | Biology and health sciences | Fossil arthropods | Animals |
Eurypterus are sexually dimorphic. On the bottom side of the first two segments of the mesosoma are central appendages used for reproduction. In females, they are long and narrow. In the males they are very short. A minority of authors, however, assume the reverse: longer genital appendage for males, shorter for female... | Eurypterus | Wikipedia | 481 | 892600 | https://en.wikipedia.org/wiki/Eurypterus | Biology and health sciences | Fossil arthropods | Animals |
The genus Eurypterus derives from E. minor, the oldest known species from the Llandovery of Scotland. E. minor is believed to have diverged from Dolichopterus macrocheirus sometime in the Llandovery. The following is the phylogenetic tree of Eurypterus based on phylogenetic studies by O. Erik Tetlie in 2006. Some speci... | Eurypterus | Wikipedia | 365 | 892600 | https://en.wikipedia.org/wiki/Eurypterus | Biology and health sciences | Fossil arthropods | Animals |
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