an organic compound belonging to the steroid family and occurring as the androgenic, or masculinizing, hormone produced by the testis. Testosterone is responsible for development of the male sex organs ... [20 Related Articles]
family of terrestrial turtles, or tortoises (order Chelonia). The group is closely related to turtles in the family Emydidae. The approximately 40 species are characterized by heavy domed shells, elephantine ...
(from the article "Chancelade skeleton") ...The 17,000-year-old skeleton was found in a curled posture-an indication of a deliberate burial-below the floor of the shelter. The Chancelade skull was studied by the French anatomist Jean-Leo Testut, ...
(from the article "Cronkite, Walter") ...Cronkite's influence is perhaps best illustrated through his commentary on the Vietnam War, which he delivered in 1968 upon returning from Vietnam, where he had reported on the aftermath of ...
(from the article "tetanus") Both the occurrence and severity of tetanus are determined by the amount of toxin produced and the resistance of the host. The neurotoxic component, tetanospasmin, is one of the deadliest ...
(from the article "dinosaur") These comprise birds and all the theropods closer to birds than to Ceratosaurus. They would include the true carnosaurs and coelurosaurs described below as well as a ...
acute infectious disease of humans and other animals, caused by toxins produced by the bacillus Clostridium tetani and characterized by rigidity and spasms of the voluntary muscles. ... [3 Related Articles]
(from the article "muscle") ...Therefore, a second pulse within that time span will not elicit any response. If, however, the pulses are 300 milliseconds apart, the muscle will be relaxing when the second pulse ...
(from the article "Behring, Emil von") ...for Hygiene, Berlin, where Robert Koch was director. There, with the Japanese bacteriologist Kitasato Shibasaburo, he showed that it was possible to provide an animal with passive immunity against tetanus ...
(from the article "tetanus") Passive protection with tetanus antitoxin should be administered in all cases of injuries that may be contaminated by clostridial spores. Active immunization with tetanus toxoid (prepared by chemical modification of ...
condition characterized by rhythmic cramping of the muscles of the hands and feet, muscle twitching, and possible spasms of the larynx, with difficulty breathing, nausea, vomiting, convulsions, and pain. Tetany ... [8 Related Articles]
port city, west-central Mozambique. Tete is situated on the right bank of the Zambezi River near the rich coal mines of Moatize. Under Portuguese influence Tete had become a market ... [2 Related Articles]
(from the article "Skiing") ...medalist Shaun White (seeBiographies) drew attention in Turin for his spectacular tricks and his splashy style, but he competed in only two World Cup events. His ...
(from the article "mountain") The interconnected system of mountain ranges and intermontane plateaus that lies between the stable areas of Africa, Arabia, and India on the south and Europe and Asia on the north ...
(from the article "nudibranch") Nudibranchs occur in the shallow waters of all the world's oceans, where they feed chiefly on other invertebrates, particularly sea anemones. Those of the family Tethyidae can swim. Among bottom ...
major regular moon of Saturn, remarkable for a fissure that wraps around the greater part of its circumference. It was discovered in 1684 by the Italian-born French astronomer Gian Domenico ... [5 Related Articles]
(from the article "Himalayas") ...features and its own geologic history. They are designated, from south to north, as the Outer, or Sub, Himalayas; the Lesser, or Lower, Himalayas; the Great, or Higher, Himalayas; and ...
former tropical body of salt water that separated the supercontinent of Laurasia in the north from Gondwana in the south during much of the Mesozoic Era (251 to 65.5 million ... [3 Related Articles]
(from the article "Asia") Along the northern margin of the Tethysides, there was a continuous transition from the Altaid evolution into the Tethyside or, more strictly speaking, into the Cimmeride evolution. In northern Tibet ...
(from the article "proboscidean") The living mammals most closely related to proboscideans are the manatees and the dugongs-marine mammals of the order Sirenia. Proboscideans and sirenians are together classified as tethytherians, in reference to ...
(from the article "Egypt, ancient") No marked change can be discerned between the reigns of Unas and Teti, the first king of the 6th dynasty. Around Teti's pyramid in the northern portion of Saqqarah was ...
(from the article "Vent, Iles du") ...and Moorea lie at the centre of the group. Maiao, covering about 3 square miles (8 square km) and located some 60 miles (95 km) west of Tahiti, is sparsely ...
American dancer, choreographer, and ballet director, whose performances and compositions integrated elements of modern dance and classical ballet. [1 Related Articles]
(from the article "Georgia") ...and often separated by deep, wild gorges. Spectacular crest-line peaks include those of Mount Shkhara, which at 16,627 feet (5,068 metres) is the highest point in Georgia, and Mounts Rustaveli, ...
(from the article "Black Hills") The Black Hills were a hunting ground and sacred territory of the Western Sioux Indians, whose rights to the region were guaranteed by the Second Treaty of Fort Laramie in ...
(from the article "Snake River") ...above King Hill, Idaho, is used for irrigation and hydropower. The main stream is regulated by several dams and reservoirs, the most expansive being American Fall Dam and Reservoir. In ...
segment of the Middle Rocky Mountains in the western United States, extending southward for 40 miles (64 km) across northwestern Wyoming, from the southern boundary of Yellowstone National Park to ... [2 Related Articles]
river in Teton county, north-central Montana, U.S. The Teton rises northeast of the Sun River on the east slopes of the Continental Divide and is joined from the south by ...
any of numerous attractively coloured freshwater fishes of the characin family, Characidae, often kept in home aquariums. Tetras are characteristically small, lively, hardy, and unaggressive. They are native to South ...
(from the article "cephalopod") ...the living cephalopods into Octopoda and Decapoda without relation to their internal structure; these were both placed in the Dibranchia, in contrast to all fossil forms, which were considered as ...
(from the article "bromine") ...lead deposits from engine cylinders during combustion. The compound is also used to destroy nematodes and other pests in soil. Bromine has other uses, as in making various dyes and ...
(from the article "Magnoliidae") ...the primitive feature of vesselless wood. With two exceptions, all vesselless angiosperms occur in the Magnoliidae. The exceptions, Trochodendron (Trochodendraceae) and Tetracentron (Tetracentraceae), show definite links with the Magnoliidae, but ...
(from the article "Trochodendrales") a small order of dicotyledonous flowering plants comprising just one family (Trochodendraceae) with two genera of evergreen trees (Trochodendron and Tetracentron), each with a single tree species. Along with Buxales, ...
(from the article "Trochodendrales") Tetracentron sinense, of central and south-central China, Nepal, and northern Myanmar (Burma), is a medium-sized tree, 4.5 to 27 metres (about 15 to 88.5 feet) tall, with palmately (fingerlike) veined ...
either of two isomeric colourless, dense, water-insoluble liquids belonging to the family of organic halogen compounds. One isomer, 1,1,2,2-tetrachloroethane, also called acetylene tetrachloride, is highly toxic. Almost the entire production ...
a colourless, dense, nonflammable, highly stable liquid belonging to the family of organic halogen compounds. Tetrachloroethylene is a powerful solvent for many organic substances. By the mid-20th century it had ... [3 Related Articles]
(from the article "chlorophenol") Tetrachlorophenol is an insecticide and a bactericide and is used as a preservative for latex, wood, and leather. Pentachlorophenol (PCP) is a disinfectant, a fungicide, and an extremely effective preservative ...
musical scale of four notes, bounded by the interval of a perfect fourth (an interval the size of two and one-half steps, e.g., c-f). In ancient Greek music the descending ... [3 Related Articles]
in classical prosody, a period made up of four colons, or a unit of four metrical sequences that each constitute a single metrical phrase of not more than about 12 ...
genus of extinct brachiopods (lamp shells) found as fossils in Triassic marine rocks (the Triassic period lasted from 251 million to 200 million years ago). Its distinctive shell has prominent ...
(from the article "Tetractinella") ...compressed in profile. One species of Tetractinella is an excellent example of a phenomenon known as homeomorphy, in which an organism simulates an unrelated organism in form and function. Tetractinella ...
any of a group of broad-spectrum antibiotic compounds that have a common basic structure and are either isolated directly from several species of Streptomyces bacteria or produced ... [10 Related Articles]
(from the article "meiosis") ...the contraction of the chromosomes in the nucleus of the diploid cell. Homologous paternal and maternal chromosomes pair up along the midline of the cell. Each pair of chromosomes-called a ...
(from the article "coccus") ...rows or chains of such cells are called streptococci; grapelike clusters of cells, staphylococci; packets of eight or more cells, sarcinae; and groups of four cells in a square arrangement, ...
a sulfide mineral of bismuth and tellurium (Bi2Te2S). It is commonly found in gold-quartz veins and contact-metamorphic deposits, as in Idu, Japan; Sorata, Bolivia; Boliden, Sweden; and Boulder county, Colo., ...
organometallic compound that is the chief antiknock agent for automotive fuels. Manufactured by the action of ethyl chloride on a powdered alloy of lead and sodium, the compound is a ... [6 Related Articles]
an organic phosphorus compound used as an insecticide, particularly for the control of aphids and red spider mites. Tetraethyl pyrophosphate is extremely poisonous to humans, the toxic effects being similar ...
(from the article "drug") ...toxin causes neuromuscular paralysis by blocking acetylcholine release (see the section Autonomic nervous system drugs). There are a few drugs that facilitate acetylcholine release, including tetraethylammonium and 4-aminopyridine. They work ...
a colourless, odourless, faintly toxic gas belonging to the family of organic halogen compounds; it is the starting material in the manufacture of polytetrafluoroethylene (q.v.), a valuable synthetic resin. [2 Related Articles]
one of the structural categories to which crystalline solids can be assigned. Crystals in this system are referred to three mutually perpendicular axes, two of which are equal in length. ... [3 Related Articles]
genus of extinct graptolites (colonial animals related to the chordates) that occur as fossils in marine rocks of the Early Ordovician Epoch (505 to 478 million years ago). The genus ...
(from the article "chemical bonding") ...in which a neighbour should lie for the strength of bonding to be maximized. In contrast, in a covalently bonded compound, the atoms adopt specific locations relative to one another, ...
(from the article "continent") ...major landform features have long been among the most intriguing problems for scientific investigation and theorizing. Among the many hypotheses that have been offered as explanation are: (1) the tetrahedral ...
common sulfosalt mineral, an antimony sulfide of copper, iron, zinc, and silver [(Cu,Fe,Zn,Ag)12Sb4S13], that is an important ore of copper and sometimes of silver. It forms gray to black metallic ...
(from the article "clay mineral") ...by various scientists including Charles Mauguin, Linus C. Pauling, W.W. Jackson, J. West, and John W. Gruner through the late 1920s to mid-1930s. These features are continuous two-dimensional tetrahedral sheets ...
active constituent of marijuana and hashish that was first isolated from the Indian hemp plant (Cannabis sativa) and synthesized in 1965. For the effects of the drug, see marijuana. [1 Related Articles]
(from the article "ether") ...(B2H6), a toxic gas that is inconvenient and hazardous to use. Borane forms stable complexes with ethers, however, and it is often supplied and used as its liquid complex with ...
(from the article "Track and Field Sports (Athletics)") ...sprinter and long jumper Marion Jones pleaded guilty in U.S. federal court to having lied to federal agents and admitted, after three years of denial, that in 1999 and 2000 ...
(from the article "pyran") ...atom are present in a ring structure. Of two possible simple pyran compounds, only one is known; it was prepared in 1962 and found to be very unstable. Among the ...
(from the article "hymenostome") any member of the evenly ciliated protozoan order Hymenostomatida. Included in this order are the genus Paramecium, often used in laboratory studies, and the even more widely studied genus Tetrahymena, ...
(from the article "organosulfur compound") ...relatively unstable, with the central atom seeking to return to the octet state by extruding one or more ligands. For example, the sigma-sulfurane (C6F5)4S, named tetrakis-(pentafluorophenyl)sulfurane, prepared at temperatures below ...
(from the article "Pythagoreanism") ...of spiritual purification; (3) the heavenly destiny of the soul and the possibility of its rising to union with the divine; (4) the appeal to certain symbols, sometimes mystical, such ...
small family of the squash order (Cucurbitales) of flowering plants containing two genera, each with one species. Octomeles sumatrana is among the tallest trees in the forests of Malesia. Tetrameles ... [1 Related Articles]
(from the article "Cucurbitales") Tetramelaceae includes two genera (Tetrameles and Octomeles) of Indo-Malesian (see Malesian subkingdom) trees, each with one species. Male and female flowers occur on different trees and are borne in pendulous ...
(from the article "Tetramelaceae") small family of the squash order (Cucurbitales) of flowering plants containing two genera, each with one species. Octomeles sumatrana is among the tallest trees in the forests of Malesia. Tetrameles ...
(from the article "evolution") DNA sequence studies on human hemoglobin genes have shown that their number is greater than previously thought. Hemoglobin molecules are tetramers (molecules made of four subunits), consisting of two polypeptides ...
(from the article "Ericales") Tetrameristaceae have glands on the inner surfaces of the sepals and only a single ovule in each part of the ovary. The flowers have only five stamens. Pelliciera rhizophorae are ...
line of poetic verse that consists of four metrical feet. In English versification, the feet are usually iambs (an unstressed syllable followed by a stressed one, as in the word ... [1 Related Articles]
(from the article "chemical compound") ...The horizontal scale does not show proton resonances in simple wavelength units. Instead, the position of each peak is normally measured relative to the absorption of the protons in the ...
(from the article "anthelmintic") ...whipworm of man and dog; thiabendazole, used primarily for the treatment of several nematodes of cattle, horses, and sheep but also used for treatment of whipworms and Strongyloides of man; ...
any member of the order Tetraodontiformes, a group of primarily tropical marine fishes that evolved from the Perciformes (the typical advanced spiny-rayed fishes) during the Eocene Period of the Cenozoic ...
(from the article "fish poisoning") Tetraodon poisoning is caused by the ingestion of certain species of pufferlike fish found in Far Eastern waters. These fishes contain a potent, heat-stable toxin that affects the human nervous ...
(from the article "bryophyte") ...widely distributed in the world but forming extensive peatland mainly in boreal regions; 1 order, 1 genus, Sphagnum, with more than 160 species.Sporophytes with elongate seta; sporangium opening by ...
(from the article "bryophyte") ...leaves with midrib, all cells with chlorophyll; widely distributed in the Northern Hemisphere, with Tetrodontium also present, but rare, in the Southern Hemisphere; 1 order, 2 genera, Tetraphis and Tetrodontium, ...
(from the article "oxide") Phosphorus forms two common oxides, phosphorus(III) oxide (or tetraphosphorus hexoxide), P4O6, and phosphorus(V) oxide (or tetraphosphorus decaoxide), P4O10. Both oxides have a structure based on the tetrahedral structure of elemental ...
(from the article "flatworm") ...with distinct external segmentation; parasitic in intestine of vertebrates. Known commonly as the "true" tapeworms; well more than 3,000 species.Scolex with 4 bothridia (leaflike muscular structure); vitellaria located in ...
(from the article "Poaceae") ...processes can be found in the gradual domestication of wheat. Among wheats there are three levels of ploidy, or sets of chromosome complements: diploid (2n), the normal condition; tetraploid (2n ...
(from the article "harbours and sea works") ...thought to the design of concrete armour units that can, by reason of their shape, overcome the disadvantages of the simple cubic, or rectangular, block. One of the most successful ...
a superclass of animals that includes all limbed vertebrates (backboned animals) constituting the classes Amphibia (amphibians), Reptilia (reptiles), Aves (birds), Mammalia (mammals), and their direct ancestors that emerged between roughly ... [4 Related Articles]
(from the article "ancient Greek civilization") ...site in Classical and Hellenistic times, seems to have been anomalously attributed to a city trittys; and an ancient local organization known as the Marathonian "Four Cities," or Tetrapolis, was ...
(from the article "spearfish") ...is a Pacific member of the genus-scarce and rather small for a billfish. Blue above and silvery below, it usually does not exceed 1.8 m (6 feet) and 27 kg ...
(from the article "coloration") ...nitrogenous 16-membered ring, or cyclic, compounds is referred to as porphyrins. The elementary structural unit of all porphyrins is a large ring itself composed of four pyrrole rings, or cyclic ...
in Greco-Roman antiquity, the ruler of a principality; originally the ruler of one-quarter of a region or province. The term was first used to denote the governor of any of ... [3 Related Articles]
(from the article "algae") The red algae, as exemplified by Polysiphonia, have some of the most complex life cycles known for living organisms. Following meiosis, four haploid tetraspores are produced, which ...
(from the article "algae") ...gametophyte tissue around it develop into a basketlike or pustulelike structure called a carposporophyte. The carposporophyte eventually produces and releases diploid carpospores that develop into tetrasporophytes. Certain cells of the ...
(from the article "nitride") Sulfur forms a variety of covalent binary nitrides, but the two most interesting ones are tetrasulfur tetranitride, S4N4, and disulfur dinitride, S2N2, because they are precursors to an unusual polymer ...
(from the article "taenite") ...At such high nickel content and temperatures below 300 °C (570 °F), the distribution of iron and nickel in the crystal structure can be highly ordered, in which case the ...
(from the article "isoprenoid") The yellow, orange, or red fat-soluble plant and animal pigments, known as carotenoids, are classed as tetraterpenes, although they have in general the molecular formula C40H56, rather than C40H64. The ...
(from the article "organosulfur compound") ...and hydrogen sulfide as the final products. There is considerable interest in the use of monomeric and polymeric compounds made from heterocyclic sulfur compounds-such as thiophene, tetrathiafulvalene (TTF), and the ...
(from the article "Equestrian Sports") Tim Tetrick dazzled harness racing fans in 2007 with his relentless quest to win more races in a single season than any other driver. The native Illinoisan, who turned 26 ...
video game created by Russian designer Alexey Pajitnov in 1985 that allows players to rotate falling blocks strategically to clear levels. Pajitnov claimed he created the name of the game ... [1 Related Articles]
vacuum-type electron tube with four electrodes. In addition to the cathode filament, anode plate, and control grid, as in the triode, an additional grid, the screen grid, is placed between ... [2 Related Articles]
(from the article "bryophyte") ...protonema filamentous but with thallose flaps; gametophores erect, with rhizoids at base, leaves with midrib, all cells with chlorophyll; widely distributed in the Northern Hemisphere, with Tetrodontium also present, but ...
(from the article "Japanese philosophy") ...Eastern thought, under the name of Indian or Chinese philosophy, was relegated to specialized courses. In order to distinguish Western philosophy from Buddhist and Chinese thought, a new term, tetsugaku ...
