text stringlengths 26 3.6k | page_title stringlengths 1 71 | source stringclasses 1
value | token_count int64 10 512 | id stringlengths 2 8 | url stringlengths 31 117 | topic stringclasses 4
values | section stringlengths 4 49 ⌀ | sublist stringclasses 9
values |
|---|---|---|---|---|---|---|---|---|
Order Artiodactyla/Clade Cetartiodactyla
Family Diacodexeidae
Family Amphimerycidae
Family Robiacinidae
Family Cainotheriidae
Suborder Tylopoda
Family Anoplotheriidae?
Family Merycoidodontidae
Family Agriochoeridae
Family Camelidae: camels, llamas, alpacas, vicuñas, and guanacos (7 extant and 13 extinct species... | Artiodactyl | Wikipedia | 502 | 46764 | https://en.wikipedia.org/wiki/Artiodactyl | Biology and health sciences | Artiodactyla | null |
Family Kogiidae: lesser sperm whales (two species)
Family Physeteridae: sperm whale (one species)
Superfamily Platanistoidea: river dolphins
Family Iniidae: South American river dolphins (two species)
Family Lipotidae: Chinese river dolphin (one species, possibly extinct)
Family Platanistidae: South Asian river do... | Artiodactyl | Wikipedia | 299 | 46764 | https://en.wikipedia.org/wiki/Artiodactyl | Biology and health sciences | Artiodactyla | null |
Research history
In the 1990s, biological systematics used not only morphology and fossils to classify organisms, but also molecular biology. Molecular biology involves sequencing an organism's DNA and RNA and comparing the sequence with that of other living beings—the more similar they are, the more closely they are ... | Artiodactyl | Wikipedia | 397 | 46764 | https://en.wikipedia.org/wiki/Artiodactyl | Biology and health sciences | Artiodactyla | null |
The oldest cetaceans date back to the early Eocene (53 million years ago), whereas the oldest known hippopotamus dates back only to the Miocene (15 million years ago). The hippopotamids are descended from the anthracotheres, a family of semiaquatic and terrestrial artiodactyls that appeared in the late Eocene, and are ... | Artiodactyl | Wikipedia | 499 | 46764 | https://en.wikipedia.org/wiki/Artiodactyl | Biology and health sciences | Artiodactyla | null |
Modern cetaceans are highly adapted sea creatures which, morphologically, have little in common with land mammals; they are similar to other marine mammals, such as seals and sea cows, due to convergent evolution. However, they evolved from originally terrestrial mammals. The most likely ancestors were long thought to ... | Artiodactyl | Wikipedia | 297 | 46764 | https://en.wikipedia.org/wiki/Artiodactyl | Biology and health sciences | Artiodactyla | null |
The four summarized Artiodactyla taxa are divided into ten extant families:
The camelids (Tylopoda) comprise only one family, Camelidae. It is a species-poor artiodactyl suborder of North American origin that is well adapted to extreme habitats—the dromedary and Bactrian camels in the Old World deserts and the guanaco... | Artiodactyl | Wikipedia | 471 | 46764 | https://en.wikipedia.org/wiki/Artiodactyl | Biology and health sciences | Artiodactyla | null |
Although deer, musk deer, and pronghorns have traditionally been summarized as cervids (Cervioidea), molecular studies provide different—and inconsistent—results, so the question of phylogenetic systematics of infraorder Pecora (the horned ruminants) for the time being, cannot be answered.
Anatomy
Artiodactyls are ge... | Artiodactyl | Wikipedia | 419 | 46764 | https://en.wikipedia.org/wiki/Artiodactyl | Biology and health sciences | Artiodactyla | null |
When camels have only two toes present, the claws are transformed into nails (while both are made of keratin, claws are curved and pointed while nails are flat and dull). These claws consist of three parts: the plate (top and sides), the sole (bottom), and the bale (rear). In general, the claws of the forelegs are wide... | Artiodactyl | Wikipedia | 395 | 46764 | https://en.wikipedia.org/wiki/Artiodactyl | Biology and health sciences | Artiodactyla | null |
True horns have a bone core that is covered in a permanent sheath of keratin, and are found only in the bovids. Antlers are bony structures that are shed and replaced each year; they are found in deer (members of the family Cervidae). They grow from a permanent outgrowth of the frontal bone called the pedicle and can b... | Artiodactyl | Wikipedia | 484 | 46764 | https://en.wikipedia.org/wiki/Artiodactyl | Biology and health sciences | Artiodactyla | null |
The molars of porcine have only a few bumps. In contrast, camels and ruminants have bumps that are crescent-shaped cusps (selenodont).
Senses
Artiodactyls have a well-developed sense of smell and sense of hearing. Unlike many other mammals, they have a poor sense of sight—moving objects are much easier to see than sta... | Artiodactyl | Wikipedia | 448 | 46764 | https://en.wikipedia.org/wiki/Artiodactyl | Biology and health sciences | Artiodactyla | null |
Tylopoda (camels, llamas, and alpacas) and chevrotains have three-chambered stomachs, while the rest of Ruminantia have four-chambered stomachs. The handicap of a heavy digestive system has increased selective pressure towards limbs that allow the animal to quickly escape predators. Most species within Suina have a sim... | Artiodactyl | Wikipedia | 500 | 46764 | https://en.wikipedia.org/wiki/Artiodactyl | Biology and health sciences | Artiodactyla | null |
The number of mammary glands is variable and correlates, as in all mammals, with litter size. Pigs, which have the largest litter size of all even-toed ungulates, have two rows of teats lined from the armpit to the groin area. In most cases, however, even-toed ungulates have only one or two pairs of teats. In some spec... | Artiodactyl | Wikipedia | 494 | 46764 | https://en.wikipedia.org/wiki/Artiodactyl | Biology and health sciences | Artiodactyla | null |
Generally, even-toed ungulates tend to have long gestation periods, smaller litter sizes, and more highly developed newborns. As with many other mammals, species in temperate or polar regions have a fixed mating season, while those in tropical areas breed year-round. They carry out polygynous mating behavior, meaning a... | Artiodactyl | Wikipedia | 442 | 46764 | https://en.wikipedia.org/wiki/Artiodactyl | Biology and health sciences | Artiodactyla | null |
Artiodactyls have been hunted by primitive humans for various reasons: for meat or fur, as well as to use their bones and teeth as weapons or tools. Their domestication began around 8000 BCE. To date, humans have domesticated goats, sheep, cattle, camels, llamas, alpacas, and pigs. Initially, livestock was used primari... | Artiodactyl | Wikipedia | 432 | 46764 | https://en.wikipedia.org/wiki/Artiodactyl | Biology and health sciences | Artiodactyla | null |
Conversely, many artiodactyls have declined significantly in numbers, and some have even gone extinct, largely due to over-hunting, and, more recently, habitat destruction. Extinct species include several gazelles, the aurochs, the Malagasy hippopotamus, the bluebuck, and Schomburgk's deer. Two species, the scimitar-ho... | Artiodactyl | Wikipedia | 145 | 46764 | https://en.wikipedia.org/wiki/Artiodactyl | Biology and health sciences | Artiodactyla | null |
A fixed-wing aircraft is a heavier-than-air aircraft, such as an airplane, which is capable of flight using aerodynamic lift. Fixed-wing aircraft are distinct from rotary-wing aircraft (in which a rotor mounted on a spinning shaft generates lift), and ornithopters (in which the wings oscillate to generate lift). The wi... | Fixed-wing aircraft | Wikipedia | 473 | 46770 | https://en.wikipedia.org/wiki/Fixed-wing%20aircraft | Technology | Aviation | null |
In 1799, Sir George Cayley laid out the concept of the modern airplane as a fixed-wing machine with systems for lift, propulsion, and control. Cayley was building and flying models of fixed-wing aircraft as early as 1803, and built a successful passenger-carrying glider in 1853. In 1856, Frenchman Jean-Marie Le Bris ma... | Fixed-wing aircraft | Wikipedia | 504 | 46770 | https://en.wikipedia.org/wiki/Fixed-wing%20aircraft | Technology | Aviation | null |
World War I served initiated the use of aircraft as weapons and observation platforms. The earliest known aerial victory with a synchronized machine gun-armed fighter aircraft occurred in 1915, flown by German Luftstreitkräfte Lieutenant Kurt Wintgens. Fighter aces appeared; the greatest (by number of air victories) wa... | Fixed-wing aircraft | Wikipedia | 491 | 46770 | https://en.wikipedia.org/wiki/Fixed-wing%20aircraft | Technology | Aviation | null |
In 1948–49, aircraft transported supplies during the Berlin Blockade. New aircraft types, such as the B-52, were produced during the Cold War.
The first jet airliner, the de Havilland Comet, was introduced in 1952, followed by the Soviet Tupolev Tu-104 in 1956. The Boeing 707, the first widely successful commercial je... | Fixed-wing aircraft | Wikipedia | 442 | 46770 | https://en.wikipedia.org/wiki/Fixed-wing%20aircraft | Technology | Aviation | null |
Many forms of glider may include a small power plant. These include:
Motor glider – a conventional glider or sailplane with an auxiliary power plant that may be used when in flight to increase performance.
Powered hang glider – a hang glider with a power plant added.
Powered parachute – a paraglider type of parachute w... | Fixed-wing aircraft | Wikipedia | 468 | 46770 | https://en.wikipedia.org/wiki/Fixed-wing%20aircraft | Technology | Aviation | null |
Gliders and sailplanes share many design elements and aerodynamic principles with powered aircraft. For example, the Horten H.IV was a tailless flying wing glider, and the delta-winged Space Shuttle orbiter glided during its descent phase. Many gliders adopt similar control surfaces and instruments as airplanes.
Types... | Fixed-wing aircraft | Wikipedia | 441 | 46770 | https://en.wikipedia.org/wiki/Fixed-wing%20aircraft | Technology | Aviation | null |
Military gliders were used during World War II for carrying troops (glider infantry) and heavy equipment to combat zones. The gliders were towed into the air and most of the way to their target by transport planes, e.g. C-47 Dakota, or by one-time bombers that had been relegated to secondary activities, e.g. Short Stir... | Fixed-wing aircraft | Wikipedia | 484 | 46770 | https://en.wikipedia.org/wiki/Fixed-wing%20aircraft | Technology | Aviation | null |
Glide bombs are bombs with aerodynamic surfaces to allow a gliding flight path rather than a ballistic one. This enables stand-off aircraft to attack a target from a distance.
Kite
A kite is a tethered aircraft held aloft by wind that blows over its wing(s). High pressure below the wing deflects the airflow downwards... | Fixed-wing aircraft | Wikipedia | 494 | 46770 | https://en.wikipedia.org/wiki/Fixed-wing%20aircraft | Technology | Aviation | null |
Wind speeds are greater at higher altitudes
Kites may be maneuvered dynamically, which dramatically increases the available force
Mechanical structures are not needed to withstand bending forces; vehicles/hulls can be light or eliminated.
Power generation
Research and development projects investigate kites for harn... | Fixed-wing aircraft | Wikipedia | 336 | 46770 | https://en.wikipedia.org/wiki/Fixed-wing%20aircraft | Technology | Aviation | null |
A fuselage, typically a long, thin body, usually with tapered or rounded ends to make its shape aerodynamically slippery. The fuselage joins the other parts of the air frame and contains the payload, and flight systems.
A vertical stabilizer or fin is a rigid surface mounted at the rear of the plane and typically prot... | Fixed-wing aircraft | Wikipedia | 496 | 46770 | https://en.wikipedia.org/wiki/Fixed-wing%20aircraft | Technology | Aviation | null |
Most planes are monoplanes, with one or two parallel wings. Biplanes and triplanes stack one wing above the other. Tandem wings place one wing behind the other, possibly joined at the tips. When the available engine power increased during the 1920s and 1930s and bracing was no longer needed, the unbraced or cantilever... | Fixed-wing aircraft | Wikipedia | 440 | 46770 | https://en.wikipedia.org/wiki/Fixed-wing%20aircraft | Technology | Aviation | null |
Pilots of manned commercial fixed-wing aircraft control them from inside a cockpit within the fuselage, typically located at the front/top, equipped with controls, windows, and instruments, separated from passengers by a secure door. In small aircraft, the passengers typically sit behind the pilot(s) in the cabin, Occa... | Fixed-wing aircraft | Wikipedia | 500 | 46770 | https://en.wikipedia.org/wiki/Fixed-wing%20aircraft | Technology | Aviation | null |
A lifting body is a configuration in which the body produces lift. In contrast to a flying wing, which is a wing with minimal or no conventional fuselage, a lifting body can be thought of as a fuselage with little or no conventional wing. Whereas a flying wing seeks to maximize cruise efficiency at subsonic speeds by e... | Fixed-wing aircraft | Wikipedia | 393 | 46770 | https://en.wikipedia.org/wiki/Fixed-wing%20aircraft | Technology | Aviation | null |
Gliders and airplanes have sophisticated control systems, especially if they are piloted.
The controls allow the pilot to direct the aircraft in the air and on the ground. Typically these are:
The yoke or joystick controls rotation of the plane about the pitch and roll axes. A yoke resembles a steering wheel. The pilot... | Fixed-wing aircraft | Wikipedia | 503 | 46770 | https://en.wikipedia.org/wiki/Fixed-wing%20aircraft | Technology | Aviation | null |
Cockpit instrumentation
On manned fixed-wing aircraft, instruments provide information to the pilots, including flight, engines, navigation, communications, and other aircraft systems that may be installed.
The six basic instruments, sometimes referred to as the six pack, are:
The airspeed indicator (ASI) shows the s... | Fixed-wing aircraft | Wikipedia | 384 | 46770 | https://en.wikipedia.org/wiki/Fixed-wing%20aircraft | Technology | Aviation | null |
Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a zygote and initiate its development into a new individual organism or offspring. While processes such as insemination or pollination, which happen befor... | Fertilisation | Wikipedia | 335 | 46828 | https://en.wikipedia.org/wiki/Fertilisation | Biology and health sciences | Health and fitness | null |
The gametes that participate in fertilisation of plants are the sperm (male) and the egg (female) cell. Various plant groups have differing methods by which the gametes produced by the male and female gametophytes come together and are fertilised. In bryophytes and pteridophytic land plants, fertilisation of the spe... | Fertilisation | Wikipedia | 472 | 46828 | https://en.wikipedia.org/wiki/Fertilisation | Biology and health sciences | Health and fitness | null |
Rupture of pollen tube
The rupture of the pollen tube to release sperm in Arabidopsis has been shown to depend on a signal from the female gametophyte. Specific proteins called FER protein kinases present in the ovule control the production of highly reactive derivatives of oxygen called reactive oxygen species (ROS).... | Fertilisation | Wikipedia | 405 | 46828 | https://en.wikipedia.org/wiki/Fertilisation | Biology and health sciences | Health and fitness | null |
Double fertilisation is the process in angiosperms (flowering plants) in which two sperm from each pollen tube fertilise two cells in a female gametophyte (sometimes called an embryo sac) that is inside an ovule. After the pollen tube enters the gametophyte, the pollen tube nucleus disintegrates and the two sperm cells... | Fertilisation | Wikipedia | 451 | 46828 | https://en.wikipedia.org/wiki/Fertilisation | Biology and health sciences | Health and fitness | null |
Outcrossing, or cross-fertilisation, and self-fertilisation represent different strategies with differing benefits and costs. An estimated 48.7% of plant species are either dioecious or self-incompatible obligate outcrossers. It is also estimated that about 42% of flowering plants exhibit a mixed mating system in nat... | Fertilisation | Wikipedia | 455 | 46828 | https://en.wikipedia.org/wiki/Fertilisation | Biology and health sciences | Health and fitness | null |
The mechanics behind fertilisation has been studied extensively in sea urchins and mice. This research addresses the question of how the sperm and the appropriate egg find each other and the question of how only one sperm gets into the egg and delivers its contents. There are three steps to fertilisation that ensure s... | Fertilisation | Wikipedia | 406 | 46828 | https://en.wikipedia.org/wiki/Fertilisation | Biology and health sciences | Health and fitness | null |
After finding the egg, the sperm penetrates the jelly coat through a process called sperm activation. In another ligand/receptor interaction, an oligosaccharide component of the egg binds and activates a receptor on the sperm and causes the acrosomal reaction. The acrosomal vesicles of the sperm fuse with the plasma me... | Fertilisation | Wikipedia | 361 | 46828 | https://en.wikipedia.org/wiki/Fertilisation | Biology and health sciences | Health and fitness | null |
When sperm are deposited into the anterior vagina, they are not capable of fertilisation (i.e., non-capacitated) and are characterised by slow linear motility patterns. This motility, combined with muscular contractions enables sperm transport towards the uterus and oviducts. There is a pH gradient within the micro-env... | Fertilisation | Wikipedia | 356 | 46828 | https://en.wikipedia.org/wiki/Fertilisation | Biology and health sciences | Health and fitness | null |
The zona pellucida, a thick layer of extracellular matrix that surrounds the egg and is similar to the role of the vitelline membrane in sea urchins, binds the sperm. Unlike sea urchins, the sperm binds to the egg before the acrosomal reaction. ZP3, a glycoprotein in the zona pellucida, is responsible for egg/sperm adh... | Fertilisation | Wikipedia | 500 | 46828 | https://en.wikipedia.org/wiki/Fertilisation | Biology and health sciences | Health and fitness | null |
In such animals as rabbits, coitus induces ovulation by stimulating the release of the pituitary hormone gonadotropin; this release greatly increases the likelihood of pregnancy.
Humans
Fertilisation in humans is the union of a human egg and sperm, usually occurring in the ampulla of the fallopian tube, producing a ... | Fertilisation | Wikipedia | 493 | 46828 | https://en.wikipedia.org/wiki/Fertilisation | Biology and health sciences | Health and fitness | null |
In many fungi (except chytrids), as in some protists, fertilisation is a two step process. First, the cytoplasms of the two gamete cells fuse (called plasmogamy), producing a dikaryotic or heterokaryotic cell with multiple nuclei. This cell may then divide to produce dikaryotic or heterokaryotic hyphae. The second step... | Fertilisation | Wikipedia | 496 | 46828 | https://en.wikipedia.org/wiki/Fertilisation | Biology and health sciences | Health and fitness | null |
The sperm aster and zygote centrosomes
Shortly after the sperm fuse with the egg, the two sperm centrioles form the embryo first centrosome and microtubule aster. The sperm centriole, found near the male pronucleus, recruit egg Pericentriolar material proteins forming the zygote first centrosome. This centrosome nucle... | Fertilisation | Wikipedia | 504 | 46828 | https://en.wikipedia.org/wiki/Fertilisation | Biology and health sciences | Health and fitness | null |
The major benefit of cross-fertilisation is generally thought to be the avoidance of inbreeding depression. Charles Darwin, in his 1876 book The Effects of Cross and Self Fertilisation in the Vegetable Kingdom (pages 466-467) summed up his findings in the following way.
"It has been shown in the present volume that the... | Fertilisation | Wikipedia | 194 | 46828 | https://en.wikipedia.org/wiki/Fertilisation | Biology and health sciences | Health and fitness | null |
Frequency-hopping spread spectrum (FHSS) is a method of transmitting radio signals by rapidly changing the carrier frequency among many frequencies occupying a large spectral band. The changes are controlled by a code known to both transmitter and receiver. FHSS is used to avoid interference, to prevent eavesdropping, ... | Frequency-hopping spread spectrum | Wikipedia | 451 | 46890 | https://en.wikipedia.org/wiki/Frequency-hopping%20spread%20spectrum | Technology | Telecommunications | null |
Some walkie-talkies that employ FHSS technology have been developed for unlicensed use on the 900 MHz band. FHSS technology is also used in many hobby transmitters and receivers used for radio-controlled model cars, airplanes, and drones. A type of multiple access is achieved allowing hundreds of transmitter/receiver p... | Frequency-hopping spread spectrum | Wikipedia | 433 | 46890 | https://en.wikipedia.org/wiki/Frequency-hopping%20spread%20spectrum | Technology | Telecommunications | null |
The earliest mentions of frequency hopping in open literature are in US patent 725,605, awarded to Nikola Tesla on March 17, 1903, and in radio pioneer Jonathan Zenneck's book Wireless Telegraphy (German, 1908, English translation McGraw Hill, 1915), although Zenneck writes that Telefunken had already tried it. Nikola ... | Frequency-hopping spread spectrum | Wikipedia | 497 | 46890 | https://en.wikipedia.org/wiki/Frequency-hopping%20spread%20spectrum | Technology | Telecommunications | null |
Frequency-hopping ideas may have been rediscovered in the 1950s during patent searches when private companies were independently developing direct-sequence Code Division Multiple Access, a non-frequency-hopping form of spread-spectrum. In 1957, engineers at Sylvania Electronic Systems Division adopted a similar idea, u... | Frequency-hopping spread spectrum | Wikipedia | 494 | 46890 | https://en.wikipedia.org/wiki/Frequency-hopping%20spread%20spectrum | Technology | Telecommunications | null |
Frequency hopping can be superimposed on other modulations or waveforms to enhance the system performance. | Frequency-hopping spread spectrum | Wikipedia | 20 | 46890 | https://en.wikipedia.org/wiki/Frequency-hopping%20spread%20spectrum | Technology | Telecommunications | null |
Otters are carnivorous mammals in the subfamily Lutrinae. The 13 extant otter species are all semiaquatic, aquatic, or marine. Lutrinae is a branch of the Mustelidae family, which includes weasels, badgers, mink, and wolverines, among other animals.
Otters' habitats include dens known as holts or couches, with their s... | Otter | Wikipedia | 455 | 46916 | https://en.wikipedia.org/wiki/Otter | Biology and health sciences | Carnivora | null |
Terminology
An otter's den is called a holt, or couch. Male otters are called dogs or boars; females are called bitches or sows; and their offspring are called pups or cubs. The collective nouns for otters are bevy, family, lodge, romp (being descriptive of their often playful nature), or, when in water, raft.
The fe... | Otter | Wikipedia | 497 | 46916 | https://en.wikipedia.org/wiki/Otter | Biology and health sciences | Carnivora | null |
Feeding
For most otters, fish is the staple of their diet. This is often supplemented by frogs, crayfish and crabs. Some otters are experts at opening shellfish, and others will feed on available small mammals or birds. Prey-dependence leaves otters very vulnerable to prey depletion. Sea otters are hunters of clams, s... | Otter | Wikipedia | 391 | 46916 | https://en.wikipedia.org/wiki/Otter | Biology and health sciences | Carnivora | null |
Genus †Lutraeximia – Italy, Pleistocene
Genus †Limnonyx – Germany, Late Miocene
Genus †Megalenhydris – Sardinia, Pleistocene
Genus †Paludolutra – Italy, Late Miocene
Genus †Sardolutra – Sardinia, Pleistocene
Genus †Siamogale – eastern Asia, Late Miocene to Early Pliocene
Genus †Sivaonyx – Asia and Africa, Late Mi... | Otter | Wikipedia | 466 | 46916 | https://en.wikipedia.org/wiki/Otter | Biology and health sciences | Carnivora | null |
Attacks on humans
A 2011 review by the IUCN/SSC Otter Specialist Group showed that otter attacks reported between 1875 and 2010 occurred most often in Florida, where human and otter populations have substantially increased since 2000, with the majority involving the North American otter. At least 42 instances of attac... | Otter | Wikipedia | 437 | 46916 | https://en.wikipedia.org/wiki/Otter | Biology and health sciences | Carnivora | null |
In the Noto region, Ishikawa Prefecture, there are stories where they shapeshift into beautiful women or children wearing checker-patterned clothing. If a human attempts to speak to one, they will answer "oraya" and then answer "araya," and if anybody asks them anything, they say cryptic things like "kawai." There are ... | Otter | Wikipedia | 461 | 46916 | https://en.wikipedia.org/wiki/Otter | Biology and health sciences | Carnivora | null |
In the Ishikawa and Kochi Prefectures, they are said to be a type of kappa, and there are stories told about how they engage in sumo with otters. In places like the Hokuriku region, Kii, and Shikoku, the otters are seen as a type of kappa. In the Kagakushū, a dictionary from the Muromachi period, an otter that grew old... | Otter | Wikipedia | 181 | 46916 | https://en.wikipedia.org/wiki/Otter | Biology and health sciences | Carnivora | null |
Caesarean section, also known as C-section, cesarean, or caesarean delivery, is the surgical procedure by which one or more babies are delivered through an incision in the mother's abdomen. It is often performed because vaginal delivery would put the mother or child at risk. Reasons for the operation include obstructed... | Caesarean section | Wikipedia | 404 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
In 2012, about 23 million C-sections were done globally. The international healthcare community has previously considered the rate of 10% and 15% to be ideal for caesarean sections. Some evidence finds a higher rate of 19% may result in better outcomes. More than 45 countries globally have C-section rates less than 7.5... | Caesarean section | Wikipedia | 384 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
Medical uses
Complications of labor and factors increasing the risk associated with vaginal delivery include:
Abnormal presentation (breech or transverse positions)
Prolonged labor or a failure to progress (obstructed labour, also known as dystocia)
Fetal distress
Cord prolapse
Uterine rupture or an elevated risk ... | Caesarean section | Wikipedia | 485 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
Some of these efforts are: emphasizing a long latent phase of labor is not abnormal and not a justification for C-section; a new definition of the start of active labor from a cervical dilatation of 4 cm to a dilatation of 6 cm; and allowing women who have previously given birth to push for at least 2 hours, with 3 hou... | Caesarean section | Wikipedia | 448 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
Women who had caesarean sections are more likely to have problems with later pregnancies, and women who want larger families should not seek an elective caesarean unless medical indications to do so exist. The risk of placenta accreta, a potentially life-threatening condition which is more likely to develop where a wom... | Caesarean section | Wikipedia | 455 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
There are several steps that can be taken during abdominal or pelvic surgery to minimize postoperative complications, such as the formation of adhesions. Such techniques and principles may include:
Handling all tissue with absolute care
Using powder-free surgical gloves
Controlling bleeding
Choosing sutures and imp... | Caesarean section | Wikipedia | 471 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
The American Congress of Obstetricians and Gynecologists and medical policy makers review research studies and find more incidence of suspected or proven sepsis, RDS, hypoglycemia, need for respiratory support, need for NICU admission, and need for hospitalization > 4–5 days. In the case of caesarean sections, rates of... | Caesarean section | Wikipedia | 479 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
Other risks include:
Wet lung (Transient Tachypnea of the Newborn): Failure to pass through the birth canal does not expose the baby to cortisol and epinephrine which typically would reverse the potassium/sodium pumps in the baby's lung. This causes fluid to remain in the lung.
Potential for early delivery and compli... | Caesarean section | Wikipedia | 499 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
A planned caesarean (or elective/scheduled caesarean), arranged ahead of time, is most commonly arranged for medical indications which have developed before or during the pregnancy, and ideally after 39 weeks of gestation. In the UK, this is classified as a 'grade 4' section (delivery timed to suit the mother or hospit... | Caesarean section | Wikipedia | 367 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
Caesarean delivery on maternal request (CDMR) is a medically unnecessary caesarean section, where the conduct of a childbirth via a caesarean section is requested by the pregnant patient even though there is not a medical indication to have the surgery. Systematic reviews have found no strong evidence about the impact ... | Caesarean section | Wikipedia | 510 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
A breech birth is the birth of a baby from a breech presentation, in which the baby exits the pelvis with the buttocks or feet first as opposed to the normal head-first presentation. In breech presentation, fetal heart sounds are heard just above the umbilicus.
Babies are usually born head first. If the baby is in ano... | Caesarean section | Wikipedia | 498 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
A resuscitative hysterotomy, also known as a peri-mortem caesarean delivery, is an emergency caesarean delivery carried out where maternal cardiac arrest has occurred, to assist in resuscitation of the mother by removing the aortocaval compression generated by the gravid uterus. Unlike other forms of caesarean section,... | Caesarean section | Wikipedia | 467 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
The Misgav Ladach method is a modified caesarean section which has been used nearly all over the world since the 1990s. It was described by Michael Stark, the president of the New European Surgical Academy, at the time he was the director of Misgav Ladach, a general hospital in Jerusalem. The method was presented durin... | Caesarean section | Wikipedia | 467 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
Caesarean section can be performed with single or double layer suturing of the uterine incision. Single layer closure compared with double layer closure has been observed to result in reduced blood loss during the surgery. It is uncertain whether this is the direct effect of the suturing technique or if other factors s... | Caesarean section | Wikipedia | 472 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
Postpartum infection is one of the main causes of maternal death and may account for 10% of maternal deaths globally. A caesarean section greatly increases the risk of infection and associated morbidity, estimated to be between 5 and 20 times as high, and routine use of antibiotic prophylaxis to prevent infections was ... | Caesarean section | Wikipedia | 460 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
It is known that during the hours of labor before a vaginal birth a woman's body begins to produce oxytocin which aids in the bonding process, and it is thought that SSC can trigger its production as well. Indeed, women have reported that they felt that SSC had helped them to feel close to and bond with their infant. ... | Caesarean section | Wikipedia | 448 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
In recent meta-analyses, caesarean section has been associated to a lower risk of urinary incontinence and pelvic organ prolapse compared to vaginal delivery. Women who have vaginal births, after a previous caesarean, are more than twice as likely to subsequently have pelvic floor surgery as those who have another caes... | Caesarean section | Wikipedia | 501 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
In Italy, the incidence of caesarean sections is particularly high, although it varies from region to region. In Campania, 60% of 2008 births reportedly occurred via caesarean sections. In the Rome region, the mean incidence is around 44%, but can reach as high as 85% in some private clinics.
United States
In the Unit... | Caesarean section | Wikipedia | 357 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
Hospitals and doctors make more money from C-section births than vaginal deliveries. Economists have calculated that hospitals may make a few thousand dollars more and doctors a few hundred. It has been found that for-profit hospitals do more c-sections than non-profit hospitals. One study looked at the rate of c-secti... | Caesarean section | Wikipedia | 495 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
The Sanskrit medical treatise Sushruta Samhita, composed in the early 1st millennium CE, mentions post-mortem caesarean sections. The first available non-mythical record of a C-section is the mother of Bindusara (born , ruled 298 – ), the second Mauryan Samrat (emperor) of India, accidentally consumed poison and died w... | Caesarean section | Wikipedia | 509 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
There is some indirect evidence that the first caesarean section that was survived by both the mother and child was performed in Prague in 1337. The mother was Beatrice of Bourbon, the second wife of the King of Bohemia John of Luxembourg. Beatrice gave birth to the king's son Wenceslaus I, later the duke of Luxembourg... | Caesarean section | Wikipedia | 454 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
The patron saint of caesarean section is Caesarius, a young deacon martyred at Terracina, who has replaced and Christianized the pagan figure of Caesar. The martyr (Saint Cesareo in Italian) is invoked for the success of this surgical procedure, because it was considered the new "Christian Caesar" – as opposed to the "... | Caesarean section | Wikipedia | 275 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
Speculations that the Roman dictator Julius Caesar was born by the method now known as C-section are false. Although caesarean sections were performed in Roman times, no classical source records a mother surviving such a delivery, while Caesar's mother lived for years after his birth. As late as the 12th century, schol... | Caesarean section | Wikipedia | 478 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
Court cases
In re A.C., 573 A.2d 1235 (1990), was a District of Columbia Court of Appeals case. It was the first American appellate court case decided against a forced Caesarean section, although the decision was issued after the fatal procedure was performed. Physicians performed a Caesarean section upon patient Angel... | Caesarean section | Wikipedia | 192 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
Pemberton v. Tallahassee Memorial Regional Center, 66 F. Supp. 2d 1247 (N.D. Fla. 1999), is a case in the United States regarding reproductive rights. Pemberton had a previous Caesarean section (vertical incision), and with her second child attempted to have a VBAC (vaginal birth after c-section). When a doctor she had... | Caesarean section | Wikipedia | 469 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
Special cases
In Judaism, there is a dispute among the poskim (Rabbinic authorities) as to whether the first-born son from a caesarean section has the laws of a bechor. Traditionally, a male child delivered by caesarean is not eligible for the Pidyon HaBen dedication ritual.
In rare cases, caesarean sections can be us... | Caesarean section | Wikipedia | 219 | 46924 | https://en.wikipedia.org/wiki/Caesarean%20section | Biology and health sciences | Surgery | Health |
The Koch snowflake (also known as the Koch curve, Koch star, or Koch island) is a fractal curve and one of the earliest fractals to have been described. It is based on the Koch curve, which appeared in a 1904 paper titled "On a Continuous Curve Without Tangents, Constructible from Elementary Geometry" by the Swedish ma... | Koch snowflake | Wikipedia | 503 | 46959 | https://en.wikipedia.org/wiki/Koch%20snowflake | Mathematics | Other | null |
A Koch curve–based representation of a nominally flat surface can similarly be created by repeatedly segmenting each line in a sawtooth pattern of segments with a given angle.
Properties
Perimeter of the Koch snowflake
Each iteration multiplies the number of sides in the Koch snowflake by four, so the number of side... | Koch snowflake | Wikipedia | 484 | 46959 | https://en.wikipedia.org/wiki/Koch%20snowflake | Mathematics | Other | null |
The fractal dimension of the Koch curve is . This is greater than that of a line () but less than that of Peano's space-filling curve ().
It is impossible to draw a tangent line to any point of the curve.
Representation as a de Rham curve
The Koch curve arises as a special case of a de Rham curve. The de Rham curves ... | Koch snowflake | Wikipedia | 510 | 46959 | https://en.wikipedia.org/wiki/Koch%20snowflake | Mathematics | Other | null |
Squares can be used to generate similar fractal curves. Starting with a unit square and adding to each side at each iteration a square with dimension one third of the squares in the previous iteration, it can be shown that both the length of the perimeter and the total area are determined by geometric progressions. The... | Koch snowflake | Wikipedia | 351 | 46959 | https://en.wikipedia.org/wiki/Koch%20snowflake | Mathematics | Other | null |
A sleep disorder, or somnipathy, is a medical disorder affecting an individual's sleep patterns, sometimes impacting physical, mental, social, and emotional functioning. Polysomnography and actigraphy are tests commonly ordered for diagnosing sleep disorders.
Sleep disorders are broadly classified into dyssomnias, par... | Sleep disorder | Wikipedia | 481 | 46966 | https://en.wikipedia.org/wiki/Sleep%20disorder | Biology and health sciences | Mental disorders | Health |
A population susceptible to the development of sleep disorders includes people who have experienced a traumatic brain injury (TBI). Due to the significant research focus on this issue, a systematic review was conducted to synthesize the findings. The results indicate that individuals who have experienced a TBI are most... | Sleep disorder | Wikipedia | 367 | 46966 | https://en.wikipedia.org/wiki/Sleep%20disorder | Biology and health sciences | Mental disorders | Health |
Sleep disturbances and Alzheimer's disease
Sleep disturbances have also been observed in Alzheimer's disease (AD), affecting about 45% of its population. When based on caregiver reports, this percentage increases to about 70%. As in the PD population, insomnia and hypersomnia are frequently recognized in AD patients. ... | Sleep disorder | Wikipedia | 507 | 46966 | https://en.wikipedia.org/wiki/Sleep%20disorder | Biology and health sciences | Mental disorders | Health |
On the other hand, it is during sleep that beta-amyloid residues are degraded to prevent plaque formation. The glymphatic system is responsible for this through the phenomenon of glymphatic clearance. Thus, during wakefulness, the AB burden is greater because the metabolic activity and oxidative stress are higher, and ... | Sleep disorder | Wikipedia | 482 | 46966 | https://en.wikipedia.org/wiki/Sleep%20disorder | Biology and health sciences | Mental disorders | Health |
However, recent studies have shown that several factors can interrupt neurogenesis, including stress and prolonged sleep deprivation (more than one day). The sleep disturbances encountered in AD could therefore suppress neurogenesis—and thus impair hippocampal functions. This would contribute to diminished memory perfo... | Sleep disorder | Wikipedia | 470 | 46966 | https://en.wikipedia.org/wiki/Sleep%20disorder | Biology and health sciences | Mental disorders | Health |
Bipolar disorder
One of the main behavioral symptoms of bipolar disorder is abnormal sleep. Studies have suggested that 23-78% of individuals with bipolar disorders consistently report symptoms of excessive time spent sleeping, or hypersomnia. The pathogenesis of bipolar disorder, including the higher risk of suicidal... | Sleep disorder | Wikipedia | 451 | 46966 | https://en.wikipedia.org/wiki/Sleep%20disorder | Biology and health sciences | Mental disorders | Health |
Management of sleep disturbances that are secondary to mental, medical, or substance abuse disorders should focus on the underlying conditions. Medications and somatic treatments may provide the most rapid symptomatic relief from certain disorders, such as narcolepsy, which is best treated with prescription drugs such ... | Sleep disorder | Wikipedia | 430 | 46966 | https://en.wikipedia.org/wiki/Sleep%20disorder | Biology and health sciences | Mental disorders | Health |
Hypnosis
Research suggests that hypnosis may be helpful in alleviating some types and manifestations of sleep disorders in some patients. "Acute and chronic insomnia often respond to relaxation and hypnotherapy approaches, along with sleep hygiene instructions." Hypnotherapy has also helped with nightmares and sleep t... | Sleep disorder | Wikipedia | 421 | 46966 | https://en.wikipedia.org/wiki/Sleep%20disorder | Biology and health sciences | Mental disorders | Health |
Melatonin
Research suggests that melatonin is useful in helping people fall asleep faster (decreased sleep latency), stay asleep longer, and experience improved sleep quality. To test this, a study was conducted that compared subjects who had taken melatonin to subjects with primary sleep disorders who had taken a pla... | Sleep disorder | Wikipedia | 468 | 46966 | https://en.wikipedia.org/wiki/Sleep%20disorder | Biology and health sciences | Mental disorders | Health |
Sleep dentistry (bruxism, snoring and sleep apnea), while not recognized as one of the nine dental specialties, qualifies for board-certification by the American Board of Dental Sleep Medicine (ABDSM). The qualified dentists collaborate with sleep physicians at accredited sleep centers, and can provide oral appliance t... | Sleep disorder | Wikipedia | 493 | 46966 | https://en.wikipedia.org/wiki/Sleep%20disorder | Biology and health sciences | Mental disorders | Health |
Nightmares are also considered a parasomnia among children, who typically remember what took place during the nightmare. However, nightmares only occur during the last stage of sleep - Rapid Eye Movement (REM) sleep. REM is the deepest stage of sleep, it is named for the host of neurological and physiological responses... | Sleep disorder | Wikipedia | 457 | 46966 | https://en.wikipedia.org/wiki/Sleep%20disorder | Biology and health sciences | Mental disorders | Health |
A separate meta-analysis focusing on this sleeping disorder in the elderly mentions that those with more than one physical or psychiatric malady experience it at a 60% higher rate than those with one condition or less. It also notes a higher prevalence of insomnia in women over the age of 50 than their male counterpart... | Sleep disorder | Wikipedia | 364 | 46966 | https://en.wikipedia.org/wiki/Sleep%20disorder | Biology and health sciences | Mental disorders | Health |
Obesity and Sleep Apnea
The worldwide incidence of obstructive sleep apnea (OSA) is on the rise, largely due to the increasing prevalence of obesity in society. In individuals who are obese, excess fat deposits in the upper respiratory tract can lead to breathing difficulties during sleep, giving rise to OSA. There is... | Sleep disorder | Wikipedia | 467 | 46966 | https://en.wikipedia.org/wiki/Sleep%20disorder | Biology and health sciences | Mental disorders | Health |
List of conditions
There are a numerous sleep disorders. The following list includes some of them:
Bruxism, involuntary grinding or clenching of the teeth while sleeping
Catathrenia, nocturnal groaning during prolonged exhalation
Delayed sleep phase disorder (DSPD), inability to awaken and fall asleep at socially ac... | Sleep disorder | Wikipedia | 463 | 46966 | https://en.wikipedia.org/wiki/Sleep%20disorder | Biology and health sciences | Mental disorders | Health |
Periodic limb movements in sleep (PLMS), sudden involuntary movement of the arms or legs during sleep. In the absence of other sleep disorders, PLMS may cause sleep disruption and impair sleep quality, leading to periodic limb movement disorder (PLMD).
Other limb movements in sleep, including hypneic jerks and nocturn... | Sleep disorder | Wikipedia | 417 | 46966 | https://en.wikipedia.org/wiki/Sleep%20disorder | Biology and health sciences | Mental disorders | Health |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.