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Torpedo (genus)
''Torpedo'' is a genus of rays, commonly known as electric rays, torpedo rays, or torpedoes. They are slow-moving bottom-dwellers capable of generating electricity as a defense and feeding mechanism. The naval weapon known as the torpedo was named after this genus, whose own name is derived from the Latin word meaning 'numb' or 'paralysed', presumably the sensation one would feel after experiencing the ray's electric shock. Electricity The largest species is the Gulf torpedo, ''Torpedo sinuspersici'', which can grow to a weight of . Electric rays have patches of modified muscle cells called electroplaques that make up an electric organ. These generate an electric gradient, similar to the normal electric potential across most cell membranes, but amplified greatly by its concentration into a very small area. The electricity can be stored in the tissues, which act as a battery. The battery can be discharged in pulses. A ray can emit a shock into the body of a prey animal to stun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Martinus Houttuyn
Maarten Houttuyn or Houttuijn (1720 – 2 May 1798) Latinised as Martinus Houttuyn, was a Dutch naturalist. Houttuyn was born in Hoorn, studied medicine in Leiden and moved to Amsterdam in 1753. He published many books on natural history, e.g. ''Natuurlyke Historie of uitvoerige Beschryving der Dieren, Planten en Mineraalen, volgens het Samenstel van den Heer Linnaeus'', in 37 volumes (1761-1773), following Carl Linnaeus' division into the animal kingdom, the plant kingdom, and the mineral kingdom. His areas of interest encompassed Pteridophytes, Bryophytes and Spermatophytes. He died in Amsterdam. In botanical nomenclature, the standard author abbreviation ''Houtt.'' is applied to plants described by him. He is commemorated by the genus ''Houttuynia'', a member of the Saururaceae from China and Japan. Martinus Houttuyn was the co-writer of the volumes 2, 3, 4 and 5 of '' Nederlandsche Vogelen''.His name appears on the title pages ovol 2 an of ''Nederlandsche Vogelen''. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Membrane
The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (the extracellular space). The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane controls the movement of substances in and out of cells and organelles, being selectively permeable to ions a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leonid Georgievich Manilo
Leonid (russian: Леонид ; uk, Леонід ; be, Леанід, Ljeaníd ) is a Slavic languages, Slavic version of the given name Leonidas I, Leonidas. The French language, French version is Leonide. People with the name include: *Leonid Andreyev (1871–1919), Russian playwright and short-story writer who led the Expressionism, Expressionist movement in the national literature *Leonid Brezhnev (1906–1982), leader of the USSR from 1964 to 1982 *Leonid Buryak (b. 1953), USSR/Ukraine-born Olympic-medal-winning soccer player and coach *Leonid Bykov (1928–1979), Soviet and Ukrainian actor, film director, and script writer *Leonid Desyatnikov (b. 1955), Soviet and Russian opera and film composer *Leonid Feodorov (1879–1935), a bishop and Exarch for the Russian Catholic Church, and survivor of the Gulag *Leonid Filatov (1946–2003), Soviet and Russian actor, director, poet, and pamphleteer *Leonid Gaidai, (1923–1993), Soviet comedy film director *Leonid Geishtor (b. 1936 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Matthias Stehmann
Matthias is a name derived from the Greek Ματθαίος, in origin similar to Matthew. People Notable people named Matthias include the following: In religion: * Saint Matthias, chosen as an apostle in Acts 1:21–26 to replace Judas Iscariot * Matthias of Trakai (–1453), Lithuanian clergyman, bishop of Samogitia and of Vilnius * Matthias Flacius, Lutheran reformer * Matthias the Prophet, see Robert Matthews (religious impostor) Claimed to be the reincarnation of the original Matthias during the Second Great Awakening * Matthias F. Cowley, Latter-day Saint apostle In the arts: * Matthias Grünewald, highly regarded painter from the German Renaissance * Matthías Jochumsson, Icelandic poet * Matthias Lechner, German film art director * Matthias Paul (actor), German actor * Matthias Schoenaerts, Belgian actor In nobility: * Matthias Corvinus of Hungary, King of Hungary * Matthias, Holy Roman Emperor, Emperor of the Holy Roman Empire (Habsburg dynasty) In music: * Matthias ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marcelo Rodrigues De Carvalho
Marcelo is a given name, the Spanish and Portuguese form of Marcellus. The Italian version of the name is Marcello, differing in having an additional "l". Marcelo may refer to: * Marcelo Costa de Andrade (born 1967), Brazilian serial killer, rapist, and necrophile *Marcelinho Carioca (Marcelo Pereira Surcin born 1971 in RJ), Brazilian international midfielder in 1990s *Marcelinho Machado (born 1975), Brazilian professional basketball player *Marcelinho Paraíba (Marcelo dos Santos b. 1975 in Paraíba state), Brazilian international midfielder *Marcelinho Paulista (Marcelo José de Souza born 1973 in SP state), Brazilian youth international in 1996 Olympics * Marcelo (footballer, born January 1987), Brazilian footballer * Marcelo (footballer, born May 1987), Brazilian footballer, who played for Lyon *Marcelo (footballer, born 1988), Brazilian footballer, who played for Real Madrid *Marcelo (footballer, born 1989), Brazilian footballer, who plays for Paços Ferreira *Marcelo Arriaga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aden Gulf Torpedo
The Aden Gulf torpedo or Aden torpedo (''Torpedo adenensis'') is a poorly known species of electric ray in the family Torpedinidae, seemingly endemic to the eastern Gulf of Aden, near the coast of Yemen. Growing to long, this species has a nearly circular pectoral fin disc and a short, thick tail with two dorsal fins and a well-developed caudal fin. It is characterized by its reddish dorsal coloration, which in contrast to related species lacks any additional markings. The International Union for Conservation of Nature (IUCN) has assessed the Aden Gulf torpedo as Endangered, citing its extremely small range and the intensive shrimp trawling that occurs in the region. Taxonomy The first specimens of the Aden Gulf torpedo were collected in 1989 by the former Soviet research ship ''Stefanov'', and described as a new species by Marcelo R. de Carvalho, M.F.W. Stehmann, and L.G. Manilo in a 2002 issue of the scientific journal ''American Museum Novitates''. The specific epithet ''adene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovoviviparity
Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop inside eggs that remain in the mother's body until they are ready to hatch. The young of some ovoviviparous amphibians, such as ''Limnonectes larvaepartus'', are born as larvae, and undergo further metamorphosis outside the body of the mother. Members of genera ''Nectophrynoides'' and ''Eleutherodactylus'' bear froglets, not only the hatching, but all the most conspicuous metamorphosis, being completed inside the body of the mother before birth. Among insects that depend on opportunistic exploitation of transient food sources, such as many Sarcophagidae and other carrion flies, and species such as many Calliphoridae, that rely on fresh dung, and parasitoids such as tachinid flies that depend on entering the host as soon as possible, the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clasper
In biology, a clasper is a male anatomical structure found in some groups of animals, used in mating. Male cartilaginous fish have claspers formed from the posterior portion of their pelvic fin which serve to channel semen into the female's cloaca during mating. The act of mating in some fish including sharks usually includes one of the claspers raised to allow water into the siphon through a specific orifice. The clasper is then inserted into the cloaca, where it opens like an umbrella to anchor its position. The siphon then begins to contract, expelling water and sperm. The claspers of many shark species have spines or hooks, which may hold them in place during copulation. Male chimaeras have cephalic claspers (tenacula) on their heads, which are thought to aid in holding the female during mating. In entomology, it is a structure in male insects that is used to hold the female during copulation (see Lepidoptera genitalia for more). See also *Sexual coercion among animals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gill Slit
Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of cartilaginous fish such as sharks and rays, as well as deep-branching vertebrates such as lampreys. In contrast, bony fishes have a single outer bony gill covering called an operculum. Most sharks and rays have five pairs of gill slits, but a few species have 6 or 7 pairs. Shark gill slits lie in a row behind the head. The anterior edge of a gill slit is motile, moving outward to allow water to exit, but closing to prevent reverse flow. A modified slit, called a spiracle, lies just behind the eye, which assists the shark with taking in water during respiration and plays a major role in bottom–dwelling sharks. Spiracles are reduced or missing in active pelagic sharks. While the shark is moving, water passes through the mouth and over the gills in a process known as "ram ventilation". While at rest, most sharks pump water over their gills t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caudal Fin
Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as seen in sharks. Apart from the tail or caudal fin, fish fins have no direct connection with the spine and are supported only by muscles. Their principal function is to help the fish swim. Fins located in different places on the fish serve different purposes such as moving forward, turning, keeping an upright position or stopping. Most fish use fins when swimming, flying fish use pectoral fins for gliding, and frogfish use them for crawling. Fins can also be used for other purposes; male sharks and mosquitofish use a modified fin to deliver sperm, thresher sharks use their caudal fin to stun prey, reef stonefish have spines in their dorsal fins that inject venom, anglerfish use the first spine of their dorsal fin like a fishing rod to lu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scribonius Largus
Scribonius Largus (c. 1-c. 50) was the court physician to the Roman emperor Claudius. About 47 AD, at the request of Gaius Julius Callistus, the emperor's freedman, he drew up a list of 271 prescriptions (''Compositiones''), most of them his own, although he acknowledged his indebtedness to his tutors, to friends, and to the writings of eminent physicians. Certain traditional remedies are also included. The work has no pretensions to style, and contains many colloquialisms. The greater part of it was transferred without acknowledgment to the work of Marcellus Empiricus (c. 410), ''De Medicamentis Empiricis, Physicis, et Rationabilibus'', which is of great value for the correction of the text of Largus. See the edition of the ''Compositiones'' by S. Sconocchia (Teubner 1983), which replaced the well-outdated edition of G. Helmreich (Teubner 1887). Works * ''De compositione medicamentorum liber''. Cratandrus, Basileae 152Digital editionby the University and State Library Düsseld ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agrin
Agrin is a large proteoglycan whose best-characterised role is in the development of the neuromuscular junction during embryogenesis. Agrin is named based on its involvement in the aggregation of acetylcholine receptors during synaptogenesis. In humans, this protein is encoded by the ''AGRN'' gene. This protein has nine domains homologous to protease inhibitors. It may also have functions in other tissues and during other stages of development. It is a major proteoglycan component in the glomerular basement membrane and may play a role in the renal filtration and cell-matrix interactions. Agrin functions by activating the MuSK protein (for Muscle-Specific Kinase), which is a receptor tyrosine kinase required for the formation and maintenance of the neuromuscular junction. Agrin is required to activate MuSK, which is similarly also required for neuromuscular junction formation. Discovery Agrin was first identified by the U.J. McMahan laboratory, Stanford University. Mechani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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