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Hand axes have traditionally been oriented with their narrowest part upwards (presupposing that this would have been the most active part, which is not unreasonable given the many hand axes that have unworked bases). The following typological conventions are used to facilitate communication. The axis of symmetry that d... | Hand axe | Wikipedia | 101 | 320336 | https://en.wikipedia.org/wiki/Hand%20axe | Technology | Hand tools | null |
Terminal zone—the narrowest end, opposite the base. Its most common shape is pointed, more or less acute or oval. Some hand axes have terminal ends that are rounded or polygonal (i.e. not pointed) while others have terminal ends that are transversal to the axis, called cleaver or spatulate.
Proximal end (base)—opposite... | Hand axe | Wikipedia | 512 | 320336 | https://en.wikipedia.org/wiki/Hand%20axe | Technology | Hand tools | null |
Hand axe measurements use the morphological axis as a reference and for orientation. In addition to length, width, depth, specialists have proposed a wide range of other physical quantities. The most common were proposed by Bordes and Balout:
Maximum length (L)
Maximum width (m)
Maximum depth (e)
Distance from the bas... | Hand axe | Wikipedia | 419 | 320336 | https://en.wikipedia.org/wiki/Hand%20axe | Technology | Hand tools | null |
Tools sometimes categorized as bifaces
Hand axes constitute an important group artefacts from the Acheulean. They are particularly important in open air archaeological sites (Keelley suggested that they are less common in cave sites). Hand axes, chopping tools and trihedral picks are considered core utensils, which wer... | Hand axe | Wikipedia | 247 | 320336 | https://en.wikipedia.org/wiki/Hand%20axe | Technology | Hand tools | null |
Another group of tools commonly associated with hand axes is the biface leafpoint tools from the Lower and Middle Palaeolithic in the Old World. The difference between the two types is based on the latter's fine, light finishing with a soft hammer and in a morphology that suggests a specific function, possibly as the p... | Hand axe | Wikipedia | 464 | 320336 | https://en.wikipedia.org/wiki/Hand%20axe | Technology | Hand tools | null |
Many authors who comment on the Westfield aspect of hand axes refer only to exceptional pieces. The majority of hand axes tended to symmetry, but lack artistic appeal. Generally, only the most striking pieces are considered, mainly 19th or early 20th century collections. At that time a lack of knowledge regarding prehi... | Hand axe | Wikipedia | 319 | 320336 | https://en.wikipedia.org/wiki/Hand%20axe | Technology | Hand tools | null |
Archaeologists have evidence of hand axes that are 1.2 million years old in Melka Kunturé (Ethiopia), but the oldest, from Konso-Gardula, could be 1.9 million years old: Although it is now known that they are the heritage of a number of human species, with Homo ergaster the earliest, up until 1954 no solid evidence ind... | Hand axe | Wikipedia | 208 | 320336 | https://en.wikipedia.org/wiki/Hand%20axe | Technology | Hand tools | null |
A hypodermic needle (from Greek ὑπο- (hypo- = under), and δέρμα (derma = skin)) is a very thin, hollow tube with one sharp tip. It is one of a category of medical tools which enter the skin, called sharps. It is commonly used with a syringe, a hand-operated device with a plunger, to inject substances into the body (e.g... | Hypodermic needle | Wikipedia | 492 | 320351 | https://en.wikipedia.org/wiki/Hypodermic%20needle | Technology | Equipment | null |
Christopher Wren performed the earliest confirmed experiments with crude hypodermic needles, performing intravenous injection into dogs in 1656. These experiments consisted of using animal bladders (as the syringe) and goose quills (as the needle) to administer drugs such as opium intravenously to dogs. Wren and others... | Hypodermic needle | Wikipedia | 475 | 320351 | https://en.wikipedia.org/wiki/Hypodermic%20needle | Technology | Equipment | null |
Modern improvements
Dr. Francis Rynd used the first "Hollow Needle" as a hypodermic syringe on Ms. Margaret Cox in Ireland on June 3rd, 1844. Dr. Wood can be largely credited with the popularization and acceptance of injection as a medical technique, as well as the widespread use and acceptance of the hypodermic needle... | Hypodermic needle | Wikipedia | 500 | 320351 | https://en.wikipedia.org/wiki/Hypodermic%20needle | Technology | Equipment | null |
Manufacture
Hypodermic needles are normally made from a stainless-steel or Niobium tube through a process known as tube drawing where the tube is drawn through progressively smaller dies to make the needle. The end of the needle is bevelled to create a sharp pointed tip, letting the needle easily penetrate the skin.
G... | Hypodermic needle | Wikipedia | 502 | 320351 | https://en.wikipedia.org/wiki/Hypodermic%20needle | Technology | Equipment | null |
Multiple sclerosis patients may also treat themselves by injection; several MS therapies, including various interferon preparations, are designed to be self-administered by subcutaneous or intramuscular injection.
Transgender people may also inject their own hormone replacement therapy, using either intramuscular inj... | Hypodermic needle | Wikipedia | 193 | 320351 | https://en.wikipedia.org/wiki/Hypodermic%20needle | Technology | Equipment | null |
Pine nuts, also called piñón (), pinoli (), or pignoli, are the edible seeds of pines (family Pinaceae, genus Pinus). According to the Food and Agriculture Organization, only 29 species provide edible nuts, while 20 are traded locally or internationally owing to their seed size being large enough to be worth harvesting... | Pine nut | Wikipedia | 413 | 320509 | https://en.wikipedia.org/wiki/Pine%20nut | Biology and health sciences | Nuts | Plants |
In North America, the main species are three of the pinyon pines: Colorado pinyon (P. edulis), single-leaf pinyon (P. monophylla), and Mexican pinyon (P. cembroides). The other eight pinyon species are used to a small extent, as is gray pine (P. sabineana), Coulter pine (P. coulteri), Torrey pine (P. torreyana), sugar ... | Pine nut | Wikipedia | 479 | 320509 | https://en.wikipedia.org/wiki/Pine%20nut | Biology and health sciences | Nuts | Plants |
Pollination and seed development
Pine nuts will not reach full maturity unless the environmental conditions are favorable for the tree and the cone. The time to maturity varies depending on the species.
For some American species, development begins in early spring with pollination. A tiny cone, about the size of a sma... | Pine nut | Wikipedia | 453 | 320509 | https://en.wikipedia.org/wiki/Pine%20nut | Biology and health sciences | Nuts | Plants |
American pinyon pine cone production is most commonly found at an elevation between , and ideally at . This is due to higher temperatures at elevations lower than during the spring, which dry up humidity and moisture content (particularly snow packs) that provide for the tree throughout the spring and summer, causing ... | Pine nut | Wikipedia | 403 | 320509 | https://en.wikipedia.org/wiki/Pine%20nut | Biology and health sciences | Nuts | Plants |
European pine nuts may be distinguished from Asian ones by their greater length than girth; Asian pine nuts are stubbier, shaped somewhat like long kernels of corn. The American piñon nuts are known for their large size and ease of shelling. In the United States, Pinus edulis, the hard shell of New Mexico and Colorado... | Pine nut | Wikipedia | 340 | 320509 | https://en.wikipedia.org/wiki/Pine%20nut | Biology and health sciences | Nuts | Plants |
In Italian, they are called pinoli (in the US, they are often called pignoli, but in Italy, pignolo is actually a word far more commonly used to describe a fussy, overly fastidious or extremely meticulous person) and are an essential component of Italian pesto sauce; the upsurge in the popularity of this sauce since th... | Pine nut | Wikipedia | 416 | 320509 | https://en.wikipedia.org/wiki/Pine%20nut | Biology and health sciences | Nuts | Plants |
Taste disturbances
Some raw pine nuts can cause pine mouth syndrome, a taste disturbance lasting from a few days to a few weeks after consumption. A bitter, metallic, unpleasant taste is reported. There are no known lasting effects, with the United States Food and Drug Administration reporting that there are "no appare... | Pine nut | Wikipedia | 306 | 320509 | https://en.wikipedia.org/wiki/Pine%20nut | Biology and health sciences | Nuts | Plants |
An air-to-air missile (AAM) is a missile fired from an aircraft for the purpose of destroying another aircraft (including unmanned aircraft such as cruise missiles). AAMs are typically powered by one or more rocket motors, usually solid fueled but sometimes liquid fueled. Ramjet engines, as used on the Meteor, are emer... | Air-to-air missile | Wikipedia | 461 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
The US Navy and US Air Force began equipping guided missiles in 1956, deploying the USAF's AIM-4 Falcon and the USN's AIM-7 Sparrow and AIM-9 Sidewinder. Post-war research led the Royal Air Force to introduce Fairey Fireflash into service in 1957 but their results were unsuccessful. The Soviet Air Force introduced its... | Air-to-air missile | Wikipedia | 484 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
On the Western side, the Norwegian-American made NASAMS air defense system has been developed for using AIM-9 Sidewinder, IRIS-T and AMRAAM air-to-air missiles to intercept targets. None of these missiles require modifications and hence it is possible for the system to take missiles straight from an aircraft. After a l... | Air-to-air missile | Wikipedia | 499 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
Active radar (AR)-guided missiles carry their own radar system to detect and track their target. However, the size of the radar antenna is limited by the small diameter of missiles, limiting its range which typically means such missiles are launched at a predicted future location of the target, often relying on separat... | Air-to-air missile | Wikipedia | 457 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
At the same time, jamming the missile lock-on is easier because the launching aircraft is further from the target than the missile, so the radar signal has to travel further and is greatly attenuated over the distance. This means that the missile may be jammed or "spoofed" by countermeasures whose signals grow stronge... | Air-to-air missile | Wikipedia | 473 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
More modern infra-red guided missiles can detect the heat of an aircraft's skin, warmed by the friction of airflow, in addition to the fainter heat signature of the engine when the aircraft is seen from the side or head-on. This, combined with greater maneuverability, gives them an "all-aspect" capability, and an attac... | Air-to-air missile | Wikipedia | 402 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
Electro-optical
A recent advancement in missile guidance is electro-optical imaging. The Israeli Python-5 has an electro-optical seeker that scans designated area for targets via optical imaging. Once a target is acquired, the missile will lock-on to it for the kill. Electro-optical seekers can be programmed to targe... | Air-to-air missile | Wikipedia | 458 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
The rear part of the missile contains the propulsion system, usually a rocket of some type and the control actuation system or CAS. Dual-thrust solid-fuel rockets are common, but some longer-range missiles use liquid-fuel motors that can "throttle" to extend their range and preserve fuel for energy-intensive final mane... | Air-to-air missile | Wikipedia | 292 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
Launch success zone The Launch Success Zone is the range within which there is a high (defined) kill probability against a target that remains unaware of its engagement until the final moment. When alerted visually or by a warning system the target attempts a last-ditch-manoeuvre sequence.
F-pole A closely related ter... | Air-to-air missile | Wikipedia | 469 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
First generation
Early short-range missiles such as the early Sidewinders and K-13 (missile) (AA-2 Atoll) had infrared seekers with a narrow (30-degree) field of view and required the attacker to position himself behind the target (rear aspect engagement). This meant that the target aircraft only had to perform a slig... | Air-to-air missile | Wikipedia | 505 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
Fourth generation
The R-73 (missile) (AA-11 Archer) entered service in 1985 and marked a new generation of dogfight missile. It had a wider field of view and could be cued onto a target using a helmet mounted sight. This allowed it to be launched at targets that would otherwise not be seen by older generation missiles... | Air-to-air missile | Wikipedia | 510 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
France
Nord AA.20, AA.25 – radio-guided, beam-riding
Matra R.510 – IR-guided
Matra R.511 – radar-guided
Matra R.550 Magic – short-range, IR-guided
Matra Magic II – IR-guided
Matra R.530 – medium-range, IR- or radar-guided
Matra Super 530F/Super 530D – medium-range, radar-guided
Matra Mistral – IR-guided
MBDA M... | Air-to-air missile | Wikipedia | 389 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
Python:
Rafael Shafrir – first Israeli domestic AAM
Rafael Shafrir 2 – improved Shafrir missile
Rafael Python 3 – medium-range IR-homing missile with all aspect capability
Rafael Python 4 – medium-range IR-homing missile with HMS-guidance capability
Python-5 – improved Python 4 with electro-optical imaging seeke... | Air-to-air missile | Wikipedia | 329 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
People's Republic of China
PL-1 – PRC version of the Soviet K-5 (missile) (AA-1 Alkali), retired.
PL-2 – PRC version of the Soviet Vympel K-13 (AA-2 Atoll), which was based on AIM-9B Sidewinder. Retired & replaced by PL-5 in PLAAF service.
PL-3 – updated version of the PL-2, did not enter service.
PL-4 – experimen... | Air-to-air missile | Wikipedia | 472 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
PL-11A – Improved PL-11 with increased range, warhead, and more effective seeker. The new seeker only requires fire-control radar guidance during the terminal stage, providing a basic LOAL (lock-on after launch) capability.
PL-11B – Also known as PL-11 AMR, improved PL-11 with AMR-1 active radar-homing seeker.
LY-60 ... | Air-to-air missile | Wikipedia | 229 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
Soviet Union/Russian Federation
K-5 (missile) (NATO reporting name AA-1 'Alkali') – beam-riding
Vympel K-13 (NATO reporting name AA-2 'Atoll') – short-range IR or SARH
Kaliningrad K-8 (NATO reporting name AA-3 'Anab') – IR or SARH
Raduga K-9 (NATO reporting name AA-4 'Awl') – IR or SARH
Bisnovat R-4 (NATO reportin... | Air-to-air missile | Wikipedia | 419 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
Turkey
Bozdoğan (Merlin) – WVRAAM (within-visual-range air-to-air missile)
Gökdoğan (Peregrine) – BVRAAM (beyond-visual-range air-to-air missile)
Akdoğan (Gyrfalcon) – Akdoğan is a 'mini' air-to-air missile intended to be cost-effective and to be used in UAVs such as Bayraktar Akıncı and TAI Aksungur.
Gökhan – it w... | Air-to-air missile | Wikipedia | 419 | 320568 | https://en.wikipedia.org/wiki/Air-to-air%20missile | Technology | Missiles | null |
Body fluids, bodily fluids, or biofluids, sometimes body liquids, are liquids within the body of an organism. In lean healthy adult men, the total body water is about 60% (60–67%) of the total body weight; it is usually slightly lower in women (52–55%). The exact percentage of fluid relative to body weight is inversely... | Body fluid | Wikipedia | 472 | 320760 | https://en.wikipedia.org/wiki/Body%20fluid | Biology and health sciences | Animal anatomy and morphology | Biology |
In mathematics, a constant function is a function whose (output) value is the same for every input value.
Basic properties
As a real-valued function of a real-valued argument, a constant function has the general form or just For example, the function is the specific constant function where the output value is . T... | Constant function | Wikipedia | 407 | 320861 | https://en.wikipedia.org/wiki/Constant%20function | Mathematics | Specific functions | null |
Every constant function whose domain and codomain are the same set is a left zero of the full transformation monoid on , which implies that it is also idempotent.
It has zero slope or gradient.
Every constant function between topological spaces is continuous.
A constant function factors through the one-point set, ... | Constant function | Wikipedia | 345 | 320861 | https://en.wikipedia.org/wiki/Constant%20function | Mathematics | Specific functions | null |
A birth defect is an abnormal condition that is present at birth, regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can range from mild to severe. Birth defects are divided into two main types: structural disorders in which problems ... | Birth defect | Wikipedia | 397 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
Terminology
A congenital physical anomaly is an abnormality of the structure of a body part. It may or may not be perceived as a problem condition. Many, if not most, people have one or more minor physical anomalies if examined carefully. Examples of minor anomalies can include curvature of the fifth finger (clinodac... | Birth defect | Wikipedia | 477 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
Examples of primarily structural congenital disorders
A limb anomaly is called a dysmelia. These include all forms of limbs anomalies, such as amelia, ectrodactyly, phocomelia, polymelia, polydactyly, syndactyly, polysyndactyly, oligodactyly, brachydactyly, achondroplasia, congenital aplasia or hypoplasia, amniotic ba... | Birth defect | Wikipedia | 496 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
However, recent animal research has shown a correlation between paternal alcohol exposure and decreased offspring birth weight. Behavioral and cognitive disorders, including difficulties with learning and memory, hyperactivity, and lowered stress tolerance have been linked to paternal alcohol ingestion. The compromised... | Birth defect | Wikipedia | 492 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
Medications and supplements
Probably, the most well-known teratogenic drug is thalidomide. It was developed near the end of the 1950s by Chemie Grünenthal as a sleep-inducing aid and antiemetic. Because of its ability to prevent nausea, it was prescribed for pregnant women in almost 50 countries worldwide between 1956... | Birth defect | Wikipedia | 246 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
Vitamin A is the sole vitamin that is embryotoxic even in a therapeutic dose, for example in multivitamins, because its metabolite, retinoic acid, plays an important role as a signal molecule in the development of several tissues and organs. Its natural precursor, β-carotene, is considered safe, whereas the consumption... | Birth defect | Wikipedia | 367 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
Several anticonvulsants are known to be highly teratogenic. Phenytoin, also known as diphenylhydantoin, along with carbamazepine, is responsible for the fetal hydantoin syndrome, which may typically include broad nose base, cleft lip and/or palate, microcephalia, nails and fingers hypoplasia, intrauterine growth restri... | Birth defect | Wikipedia | 455 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
Nitrate, which is found mostly in drinking water from ground sources, is a powerful teratogen. A case-control study in rural Australia that was conducted following frequent reports of prenatal mortality and congenital malformations found that those who drank the nitrate-containing groundwater, as opposed to rain water,... | Birth defect | Wikipedia | 376 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
The fetus is even more susceptible to damage from carbon monoxide intake, which can be harmful when inhaled during pregnancy, usually through first- or second-hand tobacco smoke. The concentration of carbon monoxide in the infant born to a nonsmoking mother is around 2%, and this concentration drastically increases to ... | Birth defect | Wikipedia | 410 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
Industrial pollution can also lead to congenital defects. Over a period of 37 years, the Chisso Corporation, a petrochemical and plastics company, contaminated the waters of Minamata Bay with an estimated 27 tons of methylmercury, contaminating the local water supply. This led many people in the area to develop what be... | Birth defect | Wikipedia | 469 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
Another issue regarding environmental justice is lead poisoning. A fetus exposed to lead during the pregnancy can result in learning difficulties and slowed growth. Some paints (before 1978) and pipes contain lead. Therefore, pregnant women who live in homes with lead paint inhale the dust containing lead, leading to l... | Birth defect | Wikipedia | 416 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
Congenital disorders were initially believed to be the result of only hereditary factors. However, in the early 1940s, Australian pediatric ophthalmologist Norman Gregg began recognizing a pattern in which the infants arriving at his surgery were developing congenital cataracts at a higher rate than those who developed... | Birth defect | Wikipedia | 501 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
Other infectious agents include cytomegalovirus, the herpes simplex virus, hyperthermia, toxoplasmosis, and syphilis. Maternal exposure to cytomegalovirus can cause microcephaly, cerebral calcifications, blindness, chorioretinitis (which can cause blindness), hepatosplenomegaly, and meningoencephalitis in fetuses. Micr... | Birth defect | Wikipedia | 476 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
For example, a lack of folic acid, a B vitamin, in the diet of a mother can cause cellular neural tube deformities that result in spina bifida. Congenital disorders such as a neural tube deformity can be prevented by 72% if the mother consumes 4 mg of folic acid before the conception and after twelve weeks of pregnancy... | Birth defect | Wikipedia | 424 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
Genetic disorders are all congenital (present at birth), though they may not be expressed or recognized until later in life. Genetic disorders may be grouped into single-gene defects, multiple-gene disorders, or chromosomal defects. Single-gene defects may arise from abnormalities of both copies of an autosomal gene (a... | Birth defect | Wikipedia | 190 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
Socioeconomics
A low socioeconomic status in a deprived neighborhood may include exposure to "environmental stressors and risk factors". Socioeconomic inequalities are commonly measured by the Cartairs-Morris score, Index of Multiple Deprivation, Townsend deprivation index, and the Jarman score. The Jarman score, for ... | Birth defect | Wikipedia | 445 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
Relatively few studies have researched the effects of paternal radiation exposure on offspring. Following the Chernobyl disaster, it was assumed in the 1990s that the germ line of irradiated fathers suffered minisatellite mutations in the DNA, which was inherited by descendants. More recently, however, the World Health... | Birth defect | Wikipedia | 410 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
Around a 5% increase in the incidence of ventricular septal defects, atrial septal defects, and patent ductus arteriosus in offspring has been found to be correlated with advanced paternal age. Advanced paternal age has also been linked to increased risk of achondroplasia and Apert syndrome. Offspring born to fathers u... | Birth defect | Wikipedia | 453 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
Newborn screening tests were introduced in the early 1960s and initially dealt with just two disorders. Since then tandem mass spectrometry, gas chromatography–mass spectrometry, and DNA analysis has made it possible for a much larger range of disorders to be screened. Newborn screening mostly measures metabolite and e... | Birth defect | Wikipedia | 464 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
About 3% of newborns have a "major physical anomaly", meaning a physical anomaly that has cosmetic or functional significance.
Physical congenital abnormalities are the leading cause of infant mortality in the United States, accounting for more than 20% of all infant deaths. Seven to ten percent of all children will re... | Birth defect | Wikipedia | 73 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
{| class="wikitable"
|+ The sex ratio of patients with congenital malformations
! Congenital anomaly !! Sex ratio, ♂♂:♀♀
|-
| Defects with female predominance ||
|-
| Congenital hip dislocation || 1 : 5.2; 1 : 5; 1 : 8; 1 : 3.7
|-
| Cleft palate || 1 : 3
|-
| Anencephaly || 1 : 1.9; 1 : 2
|-
| Craniocele || 1 : 1.8
|-
... | Birth defect | Wikipedia | 499 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
Data obtained on opposite-sex twins. ** — Data were obtained in the period 1983–1994. | Birth defect | Wikipedia | 21 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
P. M. Rajewski and A. L. Sherman (1976) have analyzed the frequency of congenital anomalies in relation to the system of the organism. Prevalence of men was recorded for the anomalies of phylogenetically younger organs and systems.
In respect of an etiology, sexual distinctions can be divided on appearing before and a... | Birth defect | Wikipedia | 234 | 321263 | https://en.wikipedia.org/wiki/Birth%20defect | Biology and health sciences | Disabilities | Health |
A railway track ( and UIC terminology) or railroad track (), also known as permanent way () or "P Way" ( and Indian English), is the structure on a railway or railroad consisting of the rails, fasteners, sleepers (railroad ties in American English) and ballast (or slab track), plus the underlying subgrade. It enables t... | Railway track | Wikipedia | 459 | 321365 | https://en.wikipedia.org/wiki/Railway%20track | Technology | Trains | null |
Most modern railroads with heavy traffic use continuously welded rails that are attached to the sleepers with base plates that spread the load. When concrete sleepers are used, a plastic or rubber pad is usually placed between the rail and the tie plate. Rail is usually attached to the sleeper with resilient fastenings... | Railway track | Wikipedia | 479 | 321365 | https://en.wikipedia.org/wiki/Railway%20track | Technology | Trains | null |
There are a number of proprietary systems; variations include a continuous reinforced concrete slab and the use of pre-cast pre-stressed concrete units laid on a base layer. Many permutations of design have been put forward.
However, ballastless track has a high initial cost, and in the case of existing railroads the ... | Railway track | Wikipedia | 477 | 321365 | https://en.wikipedia.org/wiki/Railway%20track | Technology | Trains | null |
Modern track typically uses hot-rolled steel with a profile of an asymmetrical rounded I-beam. Unlike some other uses of iron and steel, railway rails are subject to very high stresses and have to be made of very high-quality steel alloy. It took many decades to improve the quality of the materials, including the chang... | Railway track | Wikipedia | 478 | 321365 | https://en.wikipedia.org/wiki/Railway%20track | Technology | Trains | null |
Rail lengths
The rails used in rail transport are produced in sections of fixed length. Rail lengths are made as long as possible, as the joints between rails are a source of weakness. Throughout the history of rail production, lengths have increased as manufacturing processes have improved.
Timeline
The following ar... | Railway track | Wikipedia | 475 | 321365 | https://en.wikipedia.org/wiki/Railway%20track | Technology | Trains | null |
Joining rails
Rails are produced in fixed lengths and need to be joined end-to-end to make a continuous surface on which trains may run. The traditional method of joining the rails is to bolt them together using metal fishplates (jointbars in the US), producing jointed track. For more modern usage, particularly where h... | Railway track | Wikipedia | 469 | 321365 | https://en.wikipedia.org/wiki/Railway%20track | Technology | Trains | null |
Insulated joints
Where track circuits exist for signalling purposes, insulated block joints are required. These compound the weaknesses of ordinary joints. Specially-made glued joints, where all the gaps are filled with epoxy resin, increase the strength again.
As an alternative to the insulated joint, audio frequency... | Railway track | Wikipedia | 405 | 321365 | https://en.wikipedia.org/wiki/Railway%20track | Technology | Trains | null |
If not restrained, rails would lengthen in hot weather and shrink in cold weather. To provide this restraint, the rail is prevented from moving in relation to the sleeper by use of clips or anchors. Attention needs to be paid to compacting the ballast effectively, including under, between, and at the ends of the sleepe... | Railway track | Wikipedia | 478 | 321365 | https://en.wikipedia.org/wiki/Railway%20track | Technology | Trains | null |
Joints are used in the continuous welded rail when necessary, usually for signal circuit gaps. Instead of a joint that passes straight across the rail, the two rail ends are sometimes cut at an angle to give a smoother transition. In extreme cases, such as at the end of long bridges, a breather switch (referred to in N... | Railway track | Wikipedia | 494 | 321365 | https://en.wikipedia.org/wiki/Railway%20track | Technology | Trains | null |
Horizontal layout is the track layout on the horizontal plane. This involves the layout of three main track types: tangent track (straight line), curved track, and track transition curve (also called transition spiral or spiral) which connects between a tangent and a curved track.
Vertical layout is the track layout o... | Railway track | Wikipedia | 504 | 321365 | https://en.wikipedia.org/wiki/Railway%20track | Technology | Trains | null |
The surface of the head of each of the two rails can be maintained by using a railgrinder.
Common maintenance jobs include changing sleepers, lubricating and adjusting switches, tightening loose track components, and surfacing and lining track to keep straight sections straight and curves within maintenance limits. Th... | Railway track | Wikipedia | 410 | 321365 | https://en.wikipedia.org/wiki/Railway%20track | Technology | Trains | null |
Railway tracks are generally laid on a bed of stone track ballast or track bed, which in turn is supported by prepared earthworks known as the track formation. The formation comprises the subgrade and a layer of sand or stone dust (often sandwiched in impervious plastic), known as the blanket, which restricts the upwar... | Railway track | Wikipedia | 400 | 321365 | https://en.wikipedia.org/wiki/Railway%20track | Technology | Trains | null |
The hybrid use of high-performance geogrids at the subgrade and high-performance geocell in the upper subbase/subballast layer has been shown to increase the reinforcement factor greater than their separate sums, and is particularly effective in attenuating heaving of expansive subgrade clay soils. A field test project... | Railway track | Wikipedia | 205 | 321365 | https://en.wikipedia.org/wiki/Railway%20track | Technology | Trains | null |
Energy flow is the flow of energy through living things within an ecosystem. All living organisms can be organized into producers and consumers, and those producers and consumers can further be organized into a food chain. Each of the levels within the food chain is a trophic level. In order to more efficiently show th... | Energy flow (ecology) | Wikipedia | 467 | 321382 | https://en.wikipedia.org/wiki/Energy%20flow%20%28ecology%29 | Biology and health sciences | Ecology | Biology |
A producer is any organism that performs photosynthesis. Producers are important because they convert energy from the sun into a storable and usable chemical form of energy, glucose, as well as oxygen. The producers themselves can use the energy stored in glucose to perform cellular respiration. Or, if the producer is ... | Energy flow (ecology) | Wikipedia | 404 | 321382 | https://en.wikipedia.org/wiki/Energy%20flow%20%28ecology%29 | Biology and health sciences | Ecology | Biology |
Secondary production
Secondary production is the use of energy stored in plants converted by consumers to their own biomass. Different ecosystems have different levels of consumers, all end with one top consumer. Most energy is stored in organic matter of plants, and as the consumers eat these plants they take up this... | Energy flow (ecology) | Wikipedia | 357 | 321382 | https://en.wikipedia.org/wiki/Energy%20flow%20%28ecology%29 | Biology and health sciences | Ecology | Biology |
Secondary production is often described in terms of trophic levels, and while this can be useful in explaining relationships it overemphasizes the rarer interactions. Consumers often feed at multiple trophic levels. Energy transferred above the third trophic level is relatively unimportant. The assimilation efficiency... | Energy flow (ecology) | Wikipedia | 413 | 321382 | https://en.wikipedia.org/wiki/Energy%20flow%20%28ecology%29 | Biology and health sciences | Ecology | Biology |
In an aquatic ecosystem, leaf matter that falls into streams gets wet and begins to leech organic material. This happens rather quickly and will attract microbes and invertebrates. The leaves can be broken down into large pieces called coarse particulate organic matter (CPOM). The CPOM is rapidly colonized by microbes.... | Energy flow (ecology) | Wikipedia | 459 | 321382 | https://en.wikipedia.org/wiki/Energy%20flow%20%28ecology%29 | Biology and health sciences | Ecology | Biology |
Aquatic vs terrestrial ecosystems
Much variation in the flow of energy is found within each type of ecosystem, creating a challenge in identifying variation between ecosystem types. In a general sense, the flow of energy is a function of primary productivity with temperature, water availability, and light availability... | Energy flow (ecology) | Wikipedia | 389 | 321382 | https://en.wikipedia.org/wiki/Energy%20flow%20%28ecology%29 | Biology and health sciences | Ecology | Biology |
Additional factors impacting primary production includes inputs of N and P, which occurs at a greater magnitude in aquatic ecosystems. These nutrients are important in stimulating plant growth and, when passed to higher trophic levels, stimulate consumer biomass and growth rate. If either of these nutrients are in shor... | Energy flow (ecology) | Wikipedia | 456 | 321382 | https://en.wikipedia.org/wiki/Energy%20flow%20%28ecology%29 | Biology and health sciences | Ecology | Biology |
Herbivores can potentially control the fate of organic matter as it is cycled through the food web. Herbivores tend to select nutritious plants while avoiding plants with structural defense mechanisms. Like support structures, defense structures are composed of nutrient poor, high carbon cellulose. Access to nutritious... | Energy flow (ecology) | Wikipedia | 210 | 321382 | https://en.wikipedia.org/wiki/Energy%20flow%20%28ecology%29 | Biology and health sciences | Ecology | Biology |
In economics, perfect information (sometimes referred to as "no hidden information") is a feature of perfect competition. With perfect information in a market, all consumers and producers have complete and instantaneous knowledge of all market prices, their own utility, and own cost functions.
In game theory, a sequen... | Perfect information | Wikipedia | 411 | 321438 | https://en.wikipedia.org/wiki/Perfect%20information | Mathematics | Game theory | null |
The thoracic diaphragm, or simply the diaphragm (; ), is a sheet of internal skeletal muscle in humans and other mammals that extends across the bottom of the thoracic cavity. The diaphragm is the most important muscle of respiration, and separates the thoracic cavity, containing the heart and lungs, from the abdominal... | Thoracic diaphragm | Wikipedia | 457 | 321567 | https://en.wikipedia.org/wiki/Thoracic%20diaphragm | Biology and health sciences | Respiratory system | Biology |
The muscle fibres of the diaphragm radiate outward from the central tendon. While the diaphragm is one muscle, it is composed of two distinct muscle regions: the costal, which serves as the driver in the work of breathing, and crural diaphragm, which serves as an "anchor;" attaching the muscle to the lower ribs and lum... | Thoracic diaphragm | Wikipedia | 443 | 321567 | https://en.wikipedia.org/wiki/Thoracic%20diaphragm | Biology and health sciences | Respiratory system | Biology |
There are a number of openings in the diaphragm through which structures pass between the thorax and abdomen. There are three large openings — one for the aorta (aortic hiatus), one for the esophagus (esophageal hiatus), and one for the inferior vena cava (the caval opening), as well as a series of smaller openings.
T... | Thoracic diaphragm | Wikipedia | 501 | 321567 | https://en.wikipedia.org/wiki/Thoracic%20diaphragm | Biology and health sciences | Respiratory system | Biology |
The diaphragm drains blood into the brachiocephalic veins, azygos veins, and veins that drain into the inferior vena cava and left suprarenal vein.
Variation
The sternal portion of the muscle is sometimes wanting and more rarely defects occur in the lateral part of the central tendon or adjoining muscle fibers.
Devel... | Thoracic diaphragm | Wikipedia | 496 | 321567 | https://en.wikipedia.org/wiki/Thoracic%20diaphragm | Biology and health sciences | Respiratory system | Biology |
Cavity expansion happens in two extremes, along with intermediary forms. When the lower ribs are stabilized and the central tendon of the diaphragm is mobile, a contraction brings the insertion (central tendon) towards the origins and pushes the lower cavity towards the pelvis, allowing the thoracic cavity to expand do... | Thoracic diaphragm | Wikipedia | 436 | 321567 | https://en.wikipedia.org/wiki/Thoracic%20diaphragm | Biology and health sciences | Respiratory system | Biology |
Paralysis
If either the phrenic nerve, cervical spine or brainstem is damaged, this will sever the nervous supply to the diaphragm. The most common damage to the phrenic nerve is by bronchial cancer, which usually only affects one side of the diaphragm. Other causes include Guillain–Barré syndrome and systemic lupus er... | Thoracic diaphragm | Wikipedia | 425 | 321567 | https://en.wikipedia.org/wiki/Thoracic%20diaphragm | Biology and health sciences | Respiratory system | Biology |
Due to its position separating the thorax and abdomen, fluid abnormally present in the thorax, or air abnormally present in the abdomen, may collect on one side of the diaphragm. An X-ray may reveal this. Pleural effusion, in which there is fluid abnormally present between the two pleurae of the lungs, is detected by a... | Thoracic diaphragm | Wikipedia | 473 | 321567 | https://en.wikipedia.org/wiki/Thoracic%20diaphragm | Biology and health sciences | Respiratory system | Biology |
Thus the diaphragm emerges in the context of a body plan that separated an upper feeding compartment from a lower digestive tract, but the point at which it originates is a matter of definition. Structures in fish, amphibians, reptiles, and birds have been called diaphragms, but it has been argued that these structure... | Thoracic diaphragm | Wikipedia | 446 | 321567 | https://en.wikipedia.org/wiki/Thoracic%20diaphragm | Biology and health sciences | Respiratory system | Biology |
A tessellation or tiling is the covering of a surface, often a plane, using one or more geometric shapes, called tiles, with no overlaps and no gaps. In mathematics, tessellation can be generalized to higher dimensions and a variety of geometries.
A periodic tiling has a repeating pattern. Some special kinds include r... | Tessellation | Wikipedia | 465 | 321671 | https://en.wikipedia.org/wiki/Tessellation | Mathematics | Geometry | null |
Some two hundred years later in 1891, the Russian crystallographer Yevgraf Fyodorov proved that every periodic tiling of the plane features one of seventeen different groups of isometries. Fyodorov's work marked the unofficial beginning of the mathematical study of tessellations. Other prominent contributors include Al... | Tessellation | Wikipedia | 508 | 321671 | https://en.wikipedia.org/wiki/Tessellation | Mathematics | Geometry | null |
More formally, a tessellation or tiling is a cover of the Euclidean plane by a countable number of closed sets, called tiles, such that the tiles intersect only on their boundaries. These tiles may be polygons or any other shapes. Many tessellations are formed from a finite number of prototiles in which all tiles in th... | Tessellation | Wikipedia | 454 | 321671 | https://en.wikipedia.org/wiki/Tessellation | Mathematics | Geometry | null |
Mathematicians use some technical terms when discussing tilings. An edge is the intersection between two bordering tiles; it is often a straight line. A vertex is the point of intersection of three or more bordering tiles. Using these terms, an isogonal or vertex-transitive tiling is a tiling where every vertex point i... | Tessellation | Wikipedia | 475 | 321671 | https://en.wikipedia.org/wiki/Tessellation | Mathematics | Geometry | null |
An isohedral tiling is a special variation of a monohedral tiling in which all tiles belong to the same transitivity class, that is, all tiles are transforms of the same prototile under the symmetry group of the tiling. If a prototile admits a tiling, but no such tiling is isohedral, then the prototile is called anisoh... | Tessellation | Wikipedia | 501 | 321671 | https://en.wikipedia.org/wiki/Tessellation | Mathematics | Geometry | null |
Penrose tilings, which use two different quadrilateral prototiles, are the best known example of tiles that forcibly create non-periodic patterns. They belong to a general class of aperiodic tilings, which use tiles that cannot tessellate periodically. The recursive process of substitution tiling is a method of generat... | Tessellation | Wikipedia | 488 | 321671 | https://en.wikipedia.org/wiki/Tessellation | Mathematics | Geometry | null |
Sometimes the colour of a tile is understood as part of the tiling; at other times arbitrary colours may be applied later. When discussing a tiling that is displayed in colours, to avoid ambiguity, one needs to specify whether the colours are part of the tiling or just part of its illustration. This affects whether til... | Tessellation | Wikipedia | 493 | 321671 | https://en.wikipedia.org/wiki/Tessellation | Mathematics | Geometry | null |
Polyominoes are examples of tiles that are either convex of non-convex, for which various combinations, rotations, and reflections can be used to tile a plane. For results on tiling the plane with polyominoes, see Polyomino § Uses of polyominoes.
Voronoi tilings
Voronoi or Dirichlet tilings are tessellations where e... | Tessellation | Wikipedia | 504 | 321671 | https://en.wikipedia.org/wiki/Tessellation | Mathematics | Geometry | null |
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