exceed 12,000 ft (3,700 m); the highest point is Grand Teton (13,766 ft [4,196 m]), which was first ascended in 1872. Much of the range lies within Grand Teton National Park.
tetra Any of numerous attractively coloured freshwater South American and African fishes (family Charac- idae), often kept in home aquariums.
Tetras are small, lively, hardy, and unaggressive. The slender neon tetra (Paracheirodon, or Hyphessobry- con, innesi) has gleaming red hind parts and a neonlike blue-green stripe on its sides. The glowlight tetra ( Hemigrammus erythrozonus) has a shining red stripe along each side. The body of the silver tetra (Ctenobrycon spilurus) is flattened sidewise.
tetracycline Any of a class of broad-spectrum antibiotics with a common basic structure, including doxycycline. They may be isolated directly from several species of actinomycetes of the genus Streptomyces or modified from the compounds isolated. They are the drugs of choice in the treatment of cholera, rickettsial infections (see Rickettsia), psittaco¬ sis, brucellosis, and tularemia; tetracyclines are also used in the treatment of acne. Overuse of these and other antibiotics has led to drug resistance in microorganisms.
Tetragrammaton V.te-tro-'gra-mo-.tanN Greek "having four let¬ ters" Four Hebrew consonants yod, he, vav, and he —variously translit¬ erated as JHVH, JHWH, YHWH, or YHVH—that together represent the name of God. Traditionally the tetragrammaton is not pronounced; Jeho¬ vah and Yahweh are two vocalizations of it.
tetrarch Greek "ruler of a quarter" In Greco-Roman antiquity, the ruler of a principality, originally the ruler of one-quarter of a region or province. The first tetrarchs ruled the four tetrarchies of Thessaly under Philip II of Macedonia. Tetrarchs ruled in Galatia (in Asia Minor) before the Roman conquest (169 bc) and still later in Hellenized Syria and Pal¬ estine, where the title denoted the semi-independent ruler of a divided kingdom or minor district. Herod the Great’s realm after his death (4 bc) was ruled by his three sons, two of whom were called tetrarchs.
Teutates Vta-u-.ta-tezX or Toutates Vto-,ta-tez\ Celtic god, one of the three mentioned by the Roman poet Lucan in the 1st century ad, the other two being Esus and Taranis. Victims sacrificed to Teutates are believed to have been killed by being plunged headfirst into a vat filled with an unspecified liquid, possibly ale. He was identified with both Mercury and Mars. The Irish god Tuathal Techtmar, one of the legendary conquerors of Ireland, may have been another manifestation.
Teutoburg Forest Vtii-ts-.bsrgV German Teutoburger Wald
Vtoi-ts-.bur-gsr-.vahA Range of forested hills, northern Germany. It was the scene of a battle in ad 9 in which German tribes defeated the Roman legions, thus establishing the Rhine River as the German-Latin border. The Hermannsdenkmal, a colossal statue commemorating the battle, stands outside Detmold. There are numerous health and holiday resorts in the forest’s small hill towns.
Teutonic\tu-'ta-nik\ Order or Teutonic Knights officially House of the Hospitallers of Saint Mary of the Teutons Religious order important in eastern Europe in the late Middle Ages. Founded in 1189-90 to nurse the sick in Palestine during the Third Crusade, it was militarized in 1198 and given land in Jerusalem and Germany. It trans¬ ferred its base of operations to eastern Europe in the 13th century, gain¬ ing control of Prussia by 1283 and making Marienburg the centre of a military principality (1309-1525). The order extended its influence until it was defeated at the Battle of Tannenberg (1410). Another Polish victory in 1466 forced the knights to cede lands to Poland and become vassals of the Polish king. In 1525 the grand master in Prussia converted to Prot¬ estantism, dissolved the order in Prussia, and became a duke under Polish suzerainty. In other parts of Europe, especially Austria, the order survived the Reformation. Napoleon declared the order dissolved in 1809 and redis¬ tributed most of its remaining lands. In 1834 the Austrian emperor refounded it as a charitable religious order, and it is now headquartered in Vienna.
Glowlight tetras (Hemigrammus eryth¬ rozonus)
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1892 I Tewodros II ► Thailand
Tewodros II \ta-'w6-dros\ or Theodore II (b. c. 1818—d. April 13, 1868, Magela, Eth.) Emperor of Ethiopia (1855-68). Often called Ethio¬ pia’s first modern ruler, he came to the throne through the conquest of other chiefs. He reunified the various Ethiopian kingdoms into one empire, attempted to focus loyalty around the government rather than the Ethiopian church, and worked to abolish the feudal system. Though he failed in his aims, his example was followed by his successors. His reign ended when a British force under Robert Napier attacked in response to the imprisonment of several British citizens.
Texas State (pop., 2000: 20,851,820), southwestern U.S. Occupying 266,853 sq mi (691,146 sq km), it is the second largest state in both area and population. Many of Texas’s boundaries are formed by water—the course of the Red River on the north makes up two-thirds of the state’s boundary with Oklahoma; on the east the state is bordered in part by Arkansas, though the Sabine River forms most of Texas’s eastern bound¬ ary with Louisiana; the Gulf of Mexico forms the coastal boundary to the southeast; the Rio Grande carves a shallow channel that separates Texas from Mexico on the southwest; the Panhandle section juts northward, forming a counterpart in the western part of Oklahoma; and New Mexico lies to the west. The capital of Texas is Austin. Plains and hills make up the terrain, which ranges from the fertile prairie of the Coastal Plains on the Gulf of Mexico through the central Great Plains grasslands to the arid High Plains of the Panhandle. The forerunners of West Texas Indians inhabited the area as much as 37,000 years ago. Some of the peoples later formed the Caddo confederacy. Indians, including Apaches, were living in the region when the Spanish arrived in 1528. The first settlement was attempted in 1685 by the French, who claimed the region as part of Loui¬ siana. In 1803 the U.S. acquired the French claim in the Louisiana Pur¬ chase but relinquished it to Spain by treaty in 1819. It became part of Mexico at Mexican independence in 1821. In 1836 Texans declared inde¬ pendence from Mexico as the Republic of Texas (see Stephen Austin; Sam Houston). After a 10-year struggle to remain independent, Texas became the 28th U.S. state in 1845. Its boundary with Mexico was fixed after the Mexican War (1848). In the American Civil War it seceded from the Union (1861); it was readmitted in 1869. After the war, railroad building and increased shipping helped expand the economy, and the discovery of oil in 1901 transformed it. While Texas still leads all other states in oil and natural gas production and in petroleum-refining capacity, its manufac¬ ture of electronics, aerospace components, and other high-technology items is increasingly important. It is also the leading cotton, beef cattle, and sheep producer in the U.S.
Texas, University of U.S. state university system with 13 campuses throughout the state. It was founded in 1883. The main campus, at Aus¬ tin, is the second most populous campus in the U.S. It is a comprehen¬ sive research and teaching institution, offering about 100 undergraduate programs and about 190 graduate degree programs. There are more than 85 organized research units on campus, including centres for biomedical research, economic geology, and cognitive science. The Lyndon B. Johnson Library and Museum is located there.
Texas Instruments, Inc. (Tl) U.S. manufacturer of calculators, microprocessors, and digital signal processors. The direct antecedent to the company, headquartered in Dallas, Texas, was founded by John Karcher and Eugene McDermott in 1930 to provide seismographic data for the petroleum industry. In 1958 Jack Kilby, a researcher at TI, coinvented the integrated circuit (IC), and in 1967 he invented the basic design for hand¬ held calculators. In 1973 TI began to manufacture dynamic random-access memory (DRAM, commonly shortened to RAM) chips for use in comput¬ ers, and in 1982 it introduced the single-chip digital signal processor (DSP), which it employs in cell phones, Global Postioning System (GPS) receivers, and adapters for computer networks.