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Control of outbreaks requires coordinated medical services and community engagement, including rapid detection, contact tracing of those exposed, quick access to laboratory services, care for those infected, and proper disposal of the dead through cremation or burial. Prevention measures involve wearing proper protecti... | Ebola | Wikipedia | 474 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
Symptoms usually begin with a sudden influenza-like stage characterised by fatigue, fever, weakness, decreased appetite, muscular pain, joint pain, headache, and sore throat. The fever is usually higher than . This is often followed by nausea, vomiting, diarrhoea, abdominal pain, and sometimes hiccups. The combination ... | Ebola | Wikipedia | 488 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
Survivors develop antibodies against Ebola that last at least 10 years, but it is unclear whether they are immune to additional infections.
Cause
EVD in humans is caused by four of six viruses of the genus Ebolavirus. The four are Bundibugyo virus (BDBV), Sudan virus (SUDV), Taï Forest virus (TAFV) and one simply call... | Ebola | Wikipedia | 367 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
Their life cycle is thought to begin with a virion attaching to specific cell-surface receptors such as C-type lectins, DC-SIGN, or integrins, which is followed by fusion of the viral envelope with cellular membranes. The virions taken up by the cell then travel to acidic endosomes and lysosomes where the viral envelop... | Ebola | Wikipedia | 348 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
It is believed that between people, Ebola disease spreads only by direct contact with the blood or other body fluids of a person who has developed symptoms of the disease. Body fluids that may contain Ebola viruses include saliva, mucus, vomit, feces, sweat, tears, breast milk, urine and semen. The WHO states that only... | Ebola | Wikipedia | 449 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
Health-care workers treating people with Ebola are at greatest risk of infection. The risk increases when they do not have appropriate protective clothing such as masks, gowns, gloves and eye protection; do not wear it properly; or handle contaminated clothing incorrectly. This risk is particularly common in parts of A... | Ebola | Wikipedia | 436 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
Although it is not entirely clear how Ebola initially spreads from animals to humans, the spread is believed to involve direct contact with an infected wild animal or fruit bat. Besides bats, other wild animals that are sometimes infected with EBOV include several species of monkeys such as baboons, great apes (chimpan... | Ebola | Wikipedia | 509 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
Between 1976 and 1998, in 30,000 mammals, birds, reptiles, amphibians and arthropods sampled from regions of EBOV outbreaks, no Ebola virus was detected apart from some genetic traces found in six rodents (belonging to the species Mus setulosus and Praomys) and one shrew (Sylvisorex ollula) collected from the Central A... | Ebola | Wikipedia | 462 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
Endothelial cells may be infected within three days after exposure to the virus. The breakdown of endothelial cells leading to blood vessel injury can be attributed to EBOV glycoproteins. This damage occurs due to the synthesis of Ebola virus glycoprotein (GP), which reduces the availability of specific integrins respo... | Ebola | Wikipedia | 384 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
The VP24 and VP35 structural proteins of EBOV play a key role in this interference. When a cell is infected with EBOV, receptors located in the cell's cytosol (such as RIG-I and MDA5) or outside of the cytosol (such as Toll-like receptor 3 (TLR3), TLR7, TLR8 and TLR9) recognise infectious molecules associated with the ... | Ebola | Wikipedia | 443 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
The specific diagnosis of EVD is confirmed by isolating the virus, detecting its RNA or proteins, or detecting antibodies against the virus in a person's blood. Isolating the virus by cell culture, detecting the viral RNA by polymerase chain reaction (PCR) and detecting proteins by enzyme-linked immunosorbent assay (EL... | Ebola | Wikipedia | 507 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
An Ebola vaccine, rVSV-ZEBOV, was approved in the United States in December 2019. It appears to be fully effective ten days after being given. It was studied in Guinea between 2014 and 2016. More than 100,000 people have been vaccinated against Ebola . The WHO reported that approximately 345,000 people were given the v... | Ebola | Wikipedia | 504 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
Education of the general public about the risk factors for Ebola infection and of the protective measures individuals may take to prevent infection is recommended by the World Health Organization. These measures include avoiding direct contact with infected people and regular hand washing using soap and water.
Bushmea... | Ebola | Wikipedia | 506 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
Isolation
Isolation refers to separating those who are sick from those who are not. Quarantine refers to separating those who may have been exposed to a disease until they either show signs of the disease or are no longer at risk. Quarantine, also known as enforced isolation, is usually effective in decreasing spread. ... | Ebola | Wikipedia | 476 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
Where hospital care is not possible, the WHO's guidelines for home care have been relatively successful. Recommendations include using towels soaked in a bleach solution when moving infected people or bodies and also applying bleach on stains. It is also recommended that the caregivers wash hands with bleach solutions ... | Ebola | Wikipedia | 444 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
The disease typically occurs in outbreaks in tropical regions of Sub-Saharan Africa. From 1976 (when it was first identified) through 2013, the WHO reported 2,387 confirmed cases with 1,590 overall fatalities. The largest outbreak to date was the Ebola virus epidemic in West Africa, which caused a large number of death... | Ebola | Wikipedia | 405 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
Soon after Lokela's death, others who had been in contact with him also died, and people in Yambuku began to panic. The country's Minister of Health and Zaire President Mobutu Sese Seko declared the entire region, including Yambuku and the country's capital, Kinshasa, a quarantine zone. No-one was permitted to enter or... | Ebola | Wikipedia | 400 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
The virus responsible for the initial outbreak, first thought to be the Marburg virus, was later identified as a new type of virus related to the genus Marburgvirus. Virus strain samples isolated from both outbreaks were named "Ebola virus" after the Ebola River, near the first-identified viral outbreak site in Zaire. ... | Ebola | Wikipedia | 476 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
On 17 August 2012, the Ministry of Health of the DRC reported an outbreak of the Ebola-Bundibugyo variant in the eastern region. Other than its discovery in 2007, this was the only time that this variant has been identified as responsible for an outbreak. The WHO revealed that the virus had sickened 57 people and kille... | Ebola | Wikipedia | 474 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
Intense contact tracing and strict isolation largely prevented further spread of the disease in the countries that had imported cases. , suspected cases and deaths were reported; however, the WHO said that these numbers may be underestimated. Because they work closely with the body fluids of infected patients, health... | Ebola | Wikipedia | 487 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
On 12 October, the Centers for Disease Control and Prevention (CDC) confirmed that a nurse in Texas, Nina Pham, who had treated Duncan tested positive for the Ebola virus, the first known case of transmission in the United States. On 15 October, a second Texas health-care worker who had treated Duncan was confirmed to ... | Ebola | Wikipedia | 484 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
On 1 August 2018, the world's 10th Ebola outbreak was declared in North Kivu province of the Democratic Republic of the Congo. It was the first Ebola outbreak in a military conflict zone, with thousands of refugees in the area. By November 2018, nearly 200 Congolese had died of Ebola, about half of them from the city o... | Ebola | Wikipedia | 441 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
North Kivu
On 7 February 2021, the Congolese health ministry announced a new case of Ebola near Butembo, North Kivu detected a day before. The case was a 42-year-old woman who had symptoms of Ebola in Biena on 1 February 2021. A few days after, she died in a hospital in Butembo. The WHO said that more than 70 people w... | Ebola | Wikipedia | 435 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
2022
On 23 April 2022, a case of Ebola was confirmed in the DRC in the Equateur province. The case was a 31-year-old man whose symptoms began on 5 April, but did not seek treatment for over a week. On 21 April, he was admitted to an Ebola treatment centre and died later that day. By 24 May 2022, there were 5 recorded ... | Ebola | Wikipedia | 454 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
As the Ebola virus epidemic in West Africa developed in 2014, a number of popular self-published and well-reviewed books containing sensational and misleading information about the disease appeared in electronic and printed formats. The authors of some such books admitted that they lacked medical credentials and were n... | Ebola | Wikipedia | 412 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
In late 1989, Hazelton Research Products' Reston Quarantine Unit in Reston, Virginia, had an outbreak of fatal illness amongst certain lab monkeys. This lab outbreak was initially diagnosed as simian haemorrhagic fever virus (SHFV) and occurred amongst a shipment of crab-eating macaque monkeys imported from the Philipp... | Ebola | Wikipedia | 490 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
, no medication has been proven safe and effective for treating Ebola. By the time the Ebola virus epidemic in West Africa began in 2013, there were at least nine different candidate treatments. Several trials were conducted in late 2014, and early 2015, but some were abandoned due to lack of efficacy or lack of people... | Ebola | Wikipedia | 296 | 40817590 | https://en.wikipedia.org/wiki/Ebola | Biology and health sciences | Infectious disease | null |
The Dmanisi hominins, Dmanisi people, or Dmanisi man were a population of Early Pleistocene hominins whose fossils have been recovered at Dmanisi, Georgia. The fossils and stone tools recovered at Dmanisi range in age from 1.85 to 1.77 million years old, making the Dmanisi hominins the earliest well-dated hominin fossi... | Dmanisi hominins | Wikipedia | 384 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
Anatomically, the Dmanisi hominins exhibited a mosaic of traits, possessing some features reminiscent of later and more derived H. erectus and modern humans, while retaining features of earlier Homo and Australopithecus. The length and morphology of their legs was essentially modern and they would have been adapted to ... | Dmanisi hominins | Wikipedia | 510 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
During the 1983–1991 excavations, a large amount of animal fossils were collected, alongside some stone tools. The stone tools were quickly noted as highly archaic, far more primitive than other tools found in Eastern Europe. Biostratigraphically (dating through comparisons with fauna at other well-dated sites), they w... | Dmanisi hominins | Wikipedia | 459 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
Excavations continued at the site, though hominin remains proved to be rare. In 1997, the right third metatarsal bone of a hominin was discovered in the same layer as the jaw. Further discoveries were made in May 1999. Because of long-lasting periods of rainfall, the site was damaged. Archaeologist and expedition membe... | Dmanisi hominins | Wikipedia | 315 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
More discoveries followed. In 2000, another hominin jaw (D2600) was discovered, this time at a slightly lower layer (i.e. older) than the rest of the fossils. This jaw was very large and had highly developed posterior molar teeth. The following year, Skull 3 (D2700) and its corresponding jaw (D2735) was discovered, alm... | Dmanisi hominins | Wikipedia | 449 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
The D211 mandible was described in 1995 by Gabunia and Vekua, who classified it as belonging to a basal population of H. erectus based on dental similarity especially with African specimens (sometimes called H. ergaster). In 1996, palaeoanthropologists Günter Bräuer and Michael Shultz made note of both basal and derive... | Dmanisi hominins | Wikipedia | 502 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
In 2002, Vekua and colleagues described Skull 3 (D2700), including its associated mandible (D2735). They conclude that, though the individual resembled H. habilis in brain size and some facial features, it overall is consistent with an incredibly small H. ergaster.
The D2600 mandible was also described in 2002 by Gabu... | Dmanisi hominins | Wikipedia | 370 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
Lordkipanidze and colleagues described Skull 4 and its mandible in 2006, noting that it was similar to the fossils discovered previously and stating that with the possible exception of the D2600 mandible, all of the Dmanisi fossils were assignable to a single species. They agreed that the Dmanisi hominins were ancestra... | Dmanisi hominins | Wikipedia | 389 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
A 2006 comparative analysis of D211 and D2600 by palaeoanthropologists Matthew M. Skinner, Adam D. Gordon and Nicole J. Collard found that the degree of dimorphism expressed between the two mandibles was greater than expected in modern great apes and human, as well as in other extinct hominin species. They suggested tw... | Dmanisi hominins | Wikipedia | 353 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
A 2008 analysis of the teeth of Skulls 2 and 3 and the D2600 mandible by Lordkipanidze, Vekua and palaeoanthropologists María Martinón-Torres, José María Bermúdez de Castro, Aida Gómez-Robles, Ann Mergvelashvili and Leyre Prado found that like other parts of the fossils, the teeth too showed a combination of primitive ... | Dmanisi hominins | Wikipedia | 224 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
Skull 5, recovered in 2005 and described in 2013 by Lordkipanidze and colleagues, was upon its description determined to be from the same individual as the D2600 mandible and together, the two fossils significantly expanded the morphological range of the Dmanisi hominin fossils. Lordkipanidze and colleagues interpreted... | Dmanisi hominins | Wikipedia | 446 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
Palaeoanthropologists Jeffrey H. Schwartz, Ian Tattersall and Zhang Chi responded to Lordkipanidze and colleagues in 2014, disagreeing with the idea that all five skulls were from the same species. Schwartz, Tattersall and Chi also suggested that the use of a quadrinomial name, H. e. e. georgicus, was invalid in zoolog... | Dmanisi hominins | Wikipedia | 318 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
The Dmanisi research team, composed of those palaeontologists and researchers excavating at the Dmanisi site and studying the fossils, responded to Schwartz, Tattersall and Chi in the same year, maintaining that the fossils represented a single species. They noted that the distinction of H. georgicus, and the further s... | Dmanisi hominins | Wikipedia | 335 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
A 2017 analysis of Skull 5 specifically, with comparisons to the other skulls and to skulls of H. sapiens, Paranthropus boisei and other archaic hominins, by the team reaffirmed that the variation between the Dmanisi fossils was not excessive relative to the variation in most other hominins, with some features, such as... | Dmanisi hominins | Wikipedia | 397 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
The timing of the first archaic human migration out of Africa and the identity of the hominin species that undertook this migration are controversial. This derives from the sparse Early Pleistocene hominin fossil record outside of Africa. Before the discovery of the Dmanisi skulls, the earliest known hominin fossils in... | Dmanisi hominins | Wikipedia | 400 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
In 2010, the hominin-bearing level of the Dmanisi fossil site was dated through argon–argon dating as 1.81 ± 0.03 million years old, only slightly younger than the underlying layer of volcanic rock. This earlier date contradicted the previous 1.77 million year old estimate based on palaeomagnetic data. Since the D2600 ... | Dmanisi hominins | Wikipedia | 330 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
The cranial capacity of the Dmanisi hominins ranges from 546 to 775 cc, with an average of 631 cc. As such, their brain size overlaps with that of H. habilis ( 548–680 cc) and falls below the standard cranial capacity otherwise ascribed to H. erectus and H. ergaster (800–1000 cc). The encephalization quotient (brain-to... | Dmanisi hominins | Wikipedia | 494 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
Postcranial anatomy
Prior to the discovery of the Dmanisi fossils, knowledge of postcranial morphology in early Homo had been very limited. Well-preserved fossils of earlier hominins, such as Australopithecus and later Homo, such as the well-preserved skeleton of KNM WT 15000 ("Turkana Boy"; a 1.55 million year old H.... | Dmanisi hominins | Wikipedia | 240 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
Through calculations based on the size of their limb bones and a humerus (no complete skeleton has yet been recovered), the Dmanisi individuals were approximately 145–166 cm (4.8–5.4 ft) tall and weighed about 40–50 kg (88–110 lbs). They were smaller than H. ergaster in Africa, possibly either due to being more primiti... | Dmanisi hominins | Wikipedia | 280 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
Humeral torsion (the angle formed between the proximal and distal articular axis of the humerus) influences the range of movement and the orientation of the arms relative to the torso. In modern humans, the scapula (which might otherwise restrict movement) is placed dorsally, which is compensated by a high degree of hu... | Dmanisi hominins | Wikipedia | 258 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
Overall, the spine in the Dmanisi hominins appears to have been more similar to the spines of modern humans and early H. erectus than to the spines of australopithecines. The fossil vertebrae recovered at Dmanisi show lumbar lordosis, the orientation of the facet joints suggests that the range of spinal flexion in the ... | Dmanisi hominins | Wikipedia | 401 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
In the Pleistocene, the Dmanisi site would have been near a lake shore formed though the damming of the Mashavera and Pinazauri rivers by lava flow. The environment would have been temperate, relatively humid and forested; with woodland and gallery forests, open grasslands, bush lands, tree savannahs and rocky terrains... | Dmanisi hominins | Wikipedia | 261 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
Animal fossils recovered in the same sediments as the hominin remains demonstrate that Pleistocene Dmanisi would have been home to a highly diverse fauna, including pikas, lizards, hamsters, tortoises, hares, jackals and fallow deer. Most of the animals found are Villafranchian (a European land mammal age) mammals and ... | Dmanisi hominins | Wikipedia | 349 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
A large number of fossilised plant seeds have also been recovered at Dmanisi, mainly from Boraginaceae and beetroot plants. Most of the plants identified are modern species that are inedible, though some edible plants were present, such as Celtis (hackberries) and Ephedra. In conjunction with Celtis seeds being frequen... | Dmanisi hominins | Wikipedia | 350 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
Over 10,000 stone tools have been recovered at Dmanisi and their stratigraphic and spatial concentrations suggests a complex record of several reoccupations at the site. The tools found at Dmanisi are quite simple and are much the same as the tools of the Oldowan tradition created by hominins in Africa at least nearly ... | Dmanisi hominins | Wikipedia | 427 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
There is also indirect evidence of social cooperation in Skull 4, which is from an individual that had lost all but a single tooth by the time of his death. The old individual would have lived for a relatively long time after losing the teeth, indicated by the sockets of the teeth roots having been filled with bone tis... | Dmanisi hominins | Wikipedia | 154 | 60072585 | https://en.wikipedia.org/wiki/Dmanisi%20hominins | Biology and health sciences | Homo | Biology |
The evolution of tetrapods began about 400 million years ago in the Devonian Period with the earliest tetrapods evolved from lobe-finned fishes. Tetrapods (under the apomorphy-based definition used on this page) are categorized as animals in the biological superclass Tetrapoda, which includes all living and extinct amp... | Evolution of tetrapods | Wikipedia | 504 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
They did, however, have certain traits separating them from cartilaginous fishes, traits that would become pivotal in the evolution of terrestrial forms. With the exception of a pair of spiracles, the gills did not open singly to the exterior as they do in sharks; rather, they were encased in a gill chamber stiffened b... | Evolution of tetrapods | Wikipedia | 404 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
Lungs before land
The lung/swim bladder originated as an outgrowth of the gut, forming a gas-filled bladder above the digestive system. In its primitive form, the air bladder was open to the alimentary canal, a condition called physostome and still found in many fish. The primary function of swim bladder is not entirel... | Evolution of tetrapods | Wikipedia | 486 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
The breath
In order for the lungs to allow gas exchange, the lungs first need to have gas in them. In modern tetrapods, three important breathing mechanisms are conserved from early ancestors, the first being a CO2/H+ detection system. In modern tetrapod breathing, the impulse to take a breath is triggered by a build... | Evolution of tetrapods | Wikipedia | 370 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
The nostrils in most bony fish differ from those of tetrapods. Normally, bony fish have four nares (nasal openings), one naris behind the other on each side. As the fish swims, water flows into the forward pair, across the olfactory tissue, and out through the posterior openings. This is true not only of ray-finned fis... | Evolution of tetrapods | Wikipedia | 444 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
The relatives of Kenichthys soon established themselves in the waterways and brackish estuaries and became the most numerous of the bony fishes throughout the Devonian and most of the Carboniferous.
The basic anatomy of the group is well known thanks to the very detailed work on Eusthenopteron by Erik Jarvik in the se... | Evolution of tetrapods | Wikipedia | 360 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
Skull morphology
The tetrapods have their root in the early Devonian tetrapodomorph fish. Primitive tetrapods developed from an osteolepid tetrapodomorph lobe-finned fish (sarcopterygian-crossopterygian), with a two-lobed brain in a flattened skull. The coelacanth group represents marine sarcopterygians that never acqu... | Evolution of tetrapods | Wikipedia | 446 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
It has been suggested that the evolution of the tetrapod limb from fins in lobe-finned fishes is related to expression of the HOXD13 gene or the loss of the proteins actinodin 1 and actinodin 2, which are involved in fish fin development. Robot simulations suggest that the necessary nervous circuitry for walking evolve... | Evolution of tetrapods | Wikipedia | 331 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
Denizens of the swamp
The first tetrapods probably evolved in coastal and brackish marine environments, and in shallow and swampy freshwater habitats. Formerly, researchers thought the timing was towards the end of the Devonian. In 2010, this belief was challenged by the discovery of the oldest known tetrapod tracks na... | Evolution of tetrapods | Wikipedia | 467 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
By the late Devonian, land plants had stabilized freshwater habitats, allowing the first wetland ecosystems to develop, with increasingly complex food webs that afforded new opportunities. Freshwater habitats were not the only places to find water filled with organic matter and dense vegetation near the water's edge. S... | Evolution of tetrapods | Wikipedia | 432 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
Fleshy lobe-fins supported on bones rather than ray-stiffened fins seem to have been an ancestral trait of all bony fishes (Osteichthyes). The lobe-finned ancestors of the tetrapods evolved them further, while the ancestors of the ray-finned fishes (Actinopterygii) evolved their fins in a different direction. The most ... | Evolution of tetrapods | Wikipedia | 319 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
Why they went to land in the first place is still debated. One reason could be that the small juveniles who had completed their metamorphosis had what it took to make use of what land had to offer. Already adapted to breathe air and move around in shallow waters near land as a protection (just as modern fish and amphib... | Evolution of tetrapods | Wikipedia | 474 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
Until the 1990s, there was a 30 million year gap in the fossil record between the late Devonian tetrapods and the reappearance of tetrapod fossils in recognizable mid-Carboniferous amphibian lineages. It was referred to as "Romer's Gap", which now covers the period from about 360 to 345 million years ago (the Devonian-... | Evolution of tetrapods | Wikipedia | 393 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
By the Visean (mid early-Carboniferous) stage, the early tetrapods had radiated into at least three or four main branches. Some of these different branches represent the ancestors to all living tetrapods. This means that the common ancestor of all living tetrapods likely lived in the early Carboniferous. Under a narrow... | Evolution of tetrapods | Wikipedia | 357 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
Carboniferous rainforest collapse
Amphibians and reptiles were strongly affected by the Carboniferous rainforest collapse (CRC), an extinction event that occurred ~307 million years ago. The Carboniferous period has long been associated with thick, steamy swamps and humid rainforests. Since plants form the base of alm... | Evolution of tetrapods | Wikipedia | 299 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
This impacted amphibians in particular in a number of ways. The enormous drop in sea level due to greater quantities of the world's water being locked into glaciers profoundly affected the distribution and size of the semiaquatic ecosystems which amphibians favored, and the significant cooling of the climate further na... | Evolution of tetrapods | Wikipedia | 484 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
Mesozoic tetrapods
Life on Earth seemed to recover quickly after the Permian extinctions, though this was mostly in the form of disaster taxa such as the hardy Lystrosaurus. Specialized animals that formed complex ecosystems with high biodiversity, complex food webs, and a variety of niches, took much longer to recover... | Evolution of tetrapods | Wikipedia | 497 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
During the Paleocene and Eocene, most mammals remained small (under 20 kg). Cooling climate in the Oligocene and Miocene, and the expansion of grasslands favored the evolution of larger mammalian species.
Ratites run, and penguins swim and waddle: but the majority of birds are rather small, and can fly. Some birds use... | Evolution of tetrapods | Wikipedia | 312 | 38046595 | https://en.wikipedia.org/wiki/Evolution%20of%20tetrapods | Biology and health sciences | Basics_4 | Biology |
In solid-state physics, the valence band and conduction band are the bands closest to the Fermi level, and thus determine the electrical conductivity of the solid. In nonmetals, the valence band is the highest range of electron energies in which electrons are normally present at absolute zero temperature, while the con... | Valence and conduction bands | Wikipedia | 482 | 46870556 | https://en.wikipedia.org/wiki/Valence%20and%20conduction%20bands | Physical sciences | Basics_2 | Physics |
There is some conductivity in semiconductors, however. This is due to thermal excitation—some of the electrons get enough energy to jump the band gap in one go. Once they are in the conduction band, they can conduct electricity, as can the hole they left behind in the valence band. The hole is an empty state that allow... | Valence and conduction bands | Wikipedia | 244 | 46870556 | https://en.wikipedia.org/wiki/Valence%20and%20conduction%20bands | Physical sciences | Basics_2 | Physics |
Escherichia coli ( ; commonly abbreviated E. coli) is a gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms (endotherms). Most E. coli strains are harmless, but pathogenic varieties cause serious food poisoning, septic shock, meningitis, or urinary tract infection... | Pathogenic Escherichia coli | Wikipedia | 480 | 32440734 | https://en.wikipedia.org/wiki/Pathogenic%20Escherichia%20coli | Biology and health sciences | Bacterial infections | Health |
The O antigen is used for serotyping E. coli and these O group designations go from O1 to O181, with the exception of some groups which have been historically removed, namely O31, O47, O67, O72, O93 (now K84), O94, and O122; groups 174 to 181 are provisional (O174=OX3 and O175=OX7) or are under investigation (176 to 18... | Pathogenic Escherichia coli | Wikipedia | 480 | 32440734 | https://en.wikipedia.org/wiki/Pathogenic%20Escherichia%20coli | Biology and health sciences | Bacterial infections | Health |
Group II K antigens closely resemble those in gram-positive bacteria and greatly differ in composition and are further subdivided according to their acidic components, generally 20–50% of the CPS chains are bound to phospholipids.
In total there are 60 different K antigens that have been recognized (K1, K2a/ac, K3, K4... | Pathogenic Escherichia coli | Wikipedia | 489 | 32440734 | https://en.wikipedia.org/wiki/Pathogenic%20Escherichia%20coli | Biology and health sciences | Bacterial infections | Health |
Certain strains of E. coli, such as O157:H7, O104:H4, O121, O26, O103, O111, O145, and O104:H21, produce potentially lethal toxins. Food poisoning caused by E. coli can result from eating unwashed vegetables or poorly butchered and undercooked meat.
O157:H7 is also notorious for causing serious and even life-threateni... | Pathogenic Escherichia coli | Wikipedia | 507 | 32440734 | https://en.wikipedia.org/wiki/Pathogenic%20Escherichia%20coli | Biology and health sciences | Bacterial infections | Health |
Intestinal mucosa-associated E. coli are observed in increased numbers in the inflammatory bowel diseases, Crohn's disease and ulcerative colitis. Invasive strains of E. coli exist in high numbers in the inflamed tissue, and the number of bacteria in the inflamed regions correlates to the severity of the bowel inflamma... | Pathogenic Escherichia coli | Wikipedia | 335 | 32440734 | https://en.wikipedia.org/wiki/Pathogenic%20Escherichia%20coli | Biology and health sciences | Bacterial infections | Health |
ETEC strains are noninvasive, and they do not leave the intestinal lumen. ETEC is the leading bacterial cause of diarrhea in children in the developing world, as well as the most common cause of traveler's diarrhea. Each year, there are estimated to be 840 million cases of ETEC in developing countries. About 280 millio... | Pathogenic Escherichia coli | Wikipedia | 472 | 32440734 | https://en.wikipedia.org/wiki/Pathogenic%20Escherichia%20coli | Biology and health sciences | Bacterial infections | Health |
| The most infamous member of this pathotype is strain O157:H7, which causes bloody diarrhea and no fever. EHEC can cause hemolytic-uremic syndrome and sudden kidney failure. It uses bacterial fimbriae for attachment (E. coli common pilus, ECP), is moderately invasive and possesses a phage-encoded shiga toxin that can ... | Pathogenic Escherichia coli | Wikipedia | 168 | 32440734 | https://en.wikipedia.org/wiki/Pathogenic%20Escherichia%20coli | Biology and health sciences | Bacterial infections | Health |
Epidemiology of gastrointestinal infection
Transmission of pathogenic E. coli often occurs via fecal–oral transmission. Common routes of transmission include: unhygienic food preparation, farm contamination due to manure fertilization, irrigation of crops with contaminated greywater or raw sewage, feral pigs on cropla... | Pathogenic Escherichia coli | Wikipedia | 405 | 32440734 | https://en.wikipedia.org/wiki/Pathogenic%20Escherichia%20coli | Biology and health sciences | Bacterial infections | Health |
Uropathogenic E. coli use P fimbriae (pyelonephritis-associated pili) to bind urinary tract urothelial cells and colonize the bladder. These adhesins specifically bind D-galactose-D-galactose moieties on the P blood-group antigen of erythrocytes and uroepithelial cells. Approximately 1% of the human population lacks t... | Pathogenic Escherichia coli | Wikipedia | 417 | 32440734 | https://en.wikipedia.org/wiki/Pathogenic%20Escherichia%20coli | Biology and health sciences | Bacterial infections | Health |
Neonatal meningitis (NMEC)
It is produced by a serotype of Escherichia coli that contains a capsular antigen called K1. The colonization of the newborn's intestines with these strains, that are present in the mother's vagina, lead to bacteremia, which leads to meningitis. And because of the absence of the IgM antibodi... | Pathogenic Escherichia coli | Wikipedia | 422 | 32440734 | https://en.wikipedia.org/wiki/Pathogenic%20Escherichia%20coli | Biology and health sciences | Bacterial infections | Health |
Diagnosis of infectious diarrhea and identification of antimicrobial resistance is performed using a stool culture with subsequent antibiotic sensitivity testing. It requires a minimum of 2 days and maximum of several weeks to culture gastrointestinal pathogens. The sensitivity (true positive) and specificity (true ne... | Pathogenic Escherichia coli | Wikipedia | 469 | 32440734 | https://en.wikipedia.org/wiki/Pathogenic%20Escherichia%20coli | Biology and health sciences | Bacterial infections | Health |
Typically, diagnosis has been done by culturing on sorbitol-MacConkey medium and then using typing antiserum. However, current latex assays and some typing antisera have shown cross reactions with non-E. coli O157 colonies. Furthermore, not all E. coli O157 strains associated with HUS are nonsorbitol fermentors.
The C... | Pathogenic Escherichia coli | Wikipedia | 441 | 32440734 | https://en.wikipedia.org/wiki/Pathogenic%20Escherichia%20coli | Biology and health sciences | Bacterial infections | Health |
Antibiotic-resistant E. coli may also pass on the genes responsible for antibiotic resistance to other species of bacteria, such as Staphylococcus aureus, through a process called horizontal gene transfer. E. coli bacteria often carry multiple drug resistance plasmids, and under stress, readily transfer those plasmids ... | Pathogenic Escherichia coli | Wikipedia | 503 | 32440734 | https://en.wikipedia.org/wiki/Pathogenic%20Escherichia%20coli | Biology and health sciences | Bacterial infections | Health |
While phage therapy as a treatment for E. coli is unavailable in the US, some commercially available dietary supplements contain strains of phage that target E. coli and have been shown to reduce E. coli load in healthy subjects. This is not considered phage therapy, however, because it does not involve selection of ph... | Pathogenic Escherichia coli | Wikipedia | 486 | 32440734 | https://en.wikipedia.org/wiki/Pathogenic%20Escherichia%20coli | Biology and health sciences | Bacterial infections | Health |
The origin of the Moon is usually explained by a Mars-sized body striking the Earth, creating a debris ring that eventually collected into a single natural satellite, the Moon, but there are a number of variations on this giant-impact hypothesis, as well as alternative explanations, and research continues into how the ... | Origin of the Moon | Wikipedia | 510 | 38058647 | https://en.wikipedia.org/wiki/Origin%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
Computer simulations show a need for a glancing blow, which causes a portion of the collider to form a long arm of material that then shears off. The asymmetrical shape of the Earth following the collision then causes this material to settle into an orbit around the main mass. The energy involved in this collision is i... | Origin of the Moon | Wikipedia | 440 | 38058647 | https://en.wikipedia.org/wiki/Origin%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
Another issue is lunar and Earth isotope comparisons. In 2001, the most precise measurement yet of the isotopic signatures of Moon rocks was published. Surprisingly, the Apollo lunar samples carried an isotopic signature identical to Earth rocks, but different from other Solar System bodies. Because most of the materia... | Origin of the Moon | Wikipedia | 455 | 38058647 | https://en.wikipedia.org/wiki/Origin%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
Multiple impacts
In 2004, Russian astrophysicist Nikolai Gorkavyi proposed a novel model titled the multiple large asteroid impacts model, which found support from a notable group of Russian astronomers in 2013 and later, in 2017, by planetary researchers at Weizmann Institute of Science in Rehovot, Israel. In general... | Origin of the Moon | Wikipedia | 455 | 38058647 | https://en.wikipedia.org/wiki/Origin%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
It was proposed that the Pacific Ocean represented the scar of this event. Today it is known that the oceanic crust that makes up this ocean basin is relatively young, about 200 million years old or less, whereas the Moon is much older. The Moon does not consist of oceanic crust but of mantle material, which originated... | Origin of the Moon | Wikipedia | 480 | 38058647 | https://en.wikipedia.org/wiki/Origin%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
2020
A team of researchers of the Miniature Radio Frequency (Mini-RF) instrument on NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft concluded that the Moon's subsurface may be richer in metals, like iron and titanium, more than scientists had believed.
In July 2020 scientists report that the Moon formed 4.425 ±0.... | Origin of the Moon | Wikipedia | 157 | 38058647 | https://en.wikipedia.org/wiki/Origin%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
A radioactive source is a known quantity of a radionuclide which emits ionizing radiation, typically one or more of the radiation types gamma rays, alpha particles, beta particles, and neutron radiation.
Sources can be used for irradiation, where the radiation performs a significant ionising function on a target mater... | Radioactive source | Wikipedia | 476 | 49905070 | https://en.wikipedia.org/wiki/Radioactive%20source | Physical sciences | Nuclear physics | Physics |
Sealed sources are categorised by the IAEA according to their activity in relation to a minimum dangerous source (where a dangerous source is one that could cause significant injury to humans). The ratio used is A/D, where A is the activity of the source and D is the minimum dangerous activity.
Note that sources with ... | Radioactive source | Wikipedia | 483 | 49905070 | https://en.wikipedia.org/wiki/Radioactive%20source | Physical sciences | Nuclear physics | Physics |
A notorious incident of neglect in disposing of a high level source was the Goiânia accident, which resulted in several fatalities. The Tammiku radioactive material theft involved the accidental theft of caesium-137 material in Tammiku, Estonia, in 1994. | Radioactive source | Wikipedia | 55 | 49905070 | https://en.wikipedia.org/wiki/Radioactive%20source | Physical sciences | Nuclear physics | Physics |
The webbed foot is a specialized limb with interdigital membranes (webbings) that aids in aquatic locomotion, present in a variety of tetrapod vertebrates. This adaptation is primarily found in semiaquatic species, and has convergently evolved many times across vertebrate taxa.
It likely arose from mutations in deve... | Webbed foot | Wikipedia | 406 | 53769380 | https://en.wikipedia.org/wiki/Webbed%20foot | Biology and health sciences | External anatomy and regions of the body | Biology |
Webbed feet are a compromise between aquatic and terrestrial locomotion. Aquatic control surfaces of non-piscine vertebrates may be paddles or hydrofoils. Paddles generate less lift than hydrofoils, and paddling is associated with drag-based control surfaces. The roughly triangular design of webbed feet, with a broad d... | Webbed foot | Wikipedia | 507 | 53769380 | https://en.wikipedia.org/wiki/Webbed%20foot | Biology and health sciences | External anatomy and regions of the body | Biology |
Webbed feet could also arise due to being linked to other morphological changes, without a selective advantage. In salamanders, webbed feet have arisen in multiple lineages, but in most do not contribute to increased function. However, in the cave salamander species Chiropterotriton magnipes (bigfoot splayfoot salamand... | Webbed foot | Wikipedia | 318 | 53769380 | https://en.wikipedia.org/wiki/Webbed%20foot | Biology and health sciences | External anatomy and regions of the body | Biology |
Birds are typically classified as a sub-group of reptiles, but they are a distinct class within vertebrates, so are discussed separately. Birds have a wide span of representatives with webbed feet, due to the diversity of waterfowl. Ducks, geese, and swans all have webbed feet. They utilize different foraging behaviors... | Webbed foot | Wikipedia | 492 | 53769380 | https://en.wikipedia.org/wiki/Webbed%20foot | Biology and health sciences | External anatomy and regions of the body | Biology |
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