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softwood ► solar heating I 1779
by programmers in any number of programming languages. This informa¬ tion, the source code, must then be translated by means of a compiler into machine language, which the computer can understand and act on.
softwood Timber obtained from coniferous trees (mainly of the pine and fir families). With the exception of bald cypress, tamarack, and larch, softwood trees are evergreens. Softwood is mostly obtained from the Bal¬ tic, Scandinavia, and North America and is the source of about 80% of the world’s production of timber. The term sometimes imprecisely means all soft and hard woods used as construction wood in temperate regions. Softwoods of longleaf pine, Douglas fir, and yew are much harder in the mechanical sense than several hardwoods.
Soga family Japanese aristocratic family preeminent in the 7th cen¬ tury and instrumental in introducing Buddhism to Japan. Soga Umako (d. 626) overcame the powerful Mononobe and Nakatomi clans, who sup¬ ported the native Shinto religion over Buddhism, and contrived to have his niece proclaimed empress, selecting one of his nephews to be her regent (see Shotoku). The next generation alienated other aristocratic families with their high-handed ways, and after many intrigues and assas¬ sinations Soga power was crushed in 645 by Prince Nakano Oe, who was to become the emperor Tenji, aided by Fujiwara Kamatari, founder of the Fujiwara family. See also Nara period.
Sogdiana \,sag-de-'a-n3\ Ancient country of Central Asia. It was cen¬ tred in the fertile valley of the Zeravshan River, in present-day Uzbekistan. It became a satrapy of the Achaemenian dynasty under Darius I in the 6th century bc and was conquered by Alexander the Great in the 4th century. It asserted its independence from the Seleucid dynasty c. 250 bc as part of the kingdom of Bactria and fell to invading northern tribes in the 2nd cen¬ tury bc. It prospered as a centre of Islamic civilization, especially under the Samanid dynasty (9th-10th centuries ad), until the Mongol invasion of the 13th century. See also Bukhara.
Sogne Fjord Ysoq-ndX or Sognef jorden Vsog-no-.fyor-donV Longest and deepest fjord in Norway. It extends 127 mi (204 km) inland from the Norwegian Sea and has a maximum depth of 4,291 ft (1,308 m). The fjord and its branches provide some of the most picturesque scenery in Norway.
soil The biologically active, porous medium that has developed in the uppermost layer of the Earth’s crust. Soil serves as a natural reservoir of water and nutrients, as a medium for the filtration and breakdown of inju¬ rious wastes, and as a participant in the cycling of carbon and other ele¬ ments through the global ecosystem. It has evolved through the weathering of solid materials such as consolidated rocks, sediments, glacial tills, vol¬ canic ash, and organic matter. The bulk of soil consists of mineral par¬ ticles composed of silicate ions combined with various metal ions. Organic soil content consists of undecomposed or partially decomposed biomass as well as humus, an array of organic compounds derived from broken down biomass.
soil mechanics Study of soils and their utilization, especially in plan¬ ning foundations for structures and highways. How the soil of a given site will support the weight of structures or respond to movement in the course of construction depends on a number of properties (e.g., compressibility, elasticity, and permeability). Examination techniques include trench¬ digging, boring, and pumping samples to the surface with water. Seismic testing and measurement of electrical resistance also yield helpful infor¬ mation. In road construction, soil mechanics helps determine which type of pavement (rigid or flexible) will last longer. The study of soil charac¬ teristics is also used to choose the most suitable method for excavating underground tunnels. See also foundation, settling.
soil science Scientific discipline that investigates soils as primary natu¬ ral resources at the surface of the Earth. It includes the subdisciplines of pedology (study of soil formation and classification), soil biology (study of soil organisms), soil chemistry, and soil physics.
Soka-gakkai Vso-ka-'gak-klV Lay religious and political group asso¬ ciated with the Buddhist sect Nichiren-sho-shu (see Nichiren Buddhism). The most successful of Japan’s new religious movements of the 20th cen¬ tury, it draws on the 13th-century teachings of Nichiren. Like other move¬ ments in Nichiren Buddhism, it takes the Lotus Sutra as its chief scripture. Founded in 1930, Soka-gakkai came to prominence in the later 20th cen¬ tury, eventually developing a membership of over 6 million. In 1964 it established the Komeito (Clean Government Party), which by the 1980s was Japan’s third-largest political party. It also conducts educational and cultural activities.
Sokhumi formerly Sukhumi \su-'kii-me\ ancient Dioscurias. Sea¬ port (pop., 1991 est.: 120,000), Republic of Georgia. Located on the Black Sea, it was the site of an ancient Greek colony that was later held suc¬ cessively by the Romans, Byzantines, Ottomans, and Russians. It became a popular resort. After Georgia’s independence (1991), it was the centre of a rebellion for Abkhazian independence. It is the capital of the autono¬ mous republic of Abkhazia.
Sokolow \'s6-ko-16vV Anna (b. Feb. 9, 1910, Hartford, Conn., U.S.—d. March 29, 2000, New York, N.Y.) U.S. modern dancer, chore¬ ographer, and teacher. She studied with Martha Graham and danced with Graham’s company (1930-38). In the early 1930s she also formed her own dance group, the Dance Unit. From 1939 to 1949 she spent part of each year as a teacher and choreographer in Mexico City, where she formed Mexico’s first modem-dance group. Throughout her career and into the 1990s, she continued to form various companies and for them she often choreographed works on subjects of social concern.
Sokoto \so-'ko-to\ City (pop., 1996 est.: 204,900), northwestern Nige¬ ria. It lies along the Sokoto River on a traditional caravan route that leads north across the Sahara. It was the capital of the Fulani empire. Modem Sokoto is a major trade centre for agriculture and leather crafts. A pil¬ grimage centre, it is the site of mosques, a sultan’s palace, and Usman dan Fodio’s tomb and other holy shrines. Usman dan Fodio University was founded in 1975.
Sol Vsal\ In Roman religion, the name of two distinct sun gods at Rome. The original Sol, or Sol Indiges, had an annual sacrifice and shrines on the Quirinal and in the Circus Maximus. After the importation of various Syrian sun cults, Elagabalus built a temple to Sol Invictus on the Palatine and attempted to make his worship the principal religion at Rome. Aure- lian later reestablished the worship and erected a temple to Sol in the Campus Agrippae. The worship of Sol remained the chief imperial cult until the rise of Christianity.
solar cell Any device that directly converts the energy in light into elec¬ trical energy through the process of photovoltaics (see photovoltaic effect). Solar cells do not use chemical reactions to produce electric power, and they have no moving parts. Most solar cells are designed for converting sunlight into electricity. In large arrays, which may contain many thousands of individual cells, they can function as central electric power stations analogous to nuclear, coal-, or oil-fired power plants. Much smaller assem¬ blies of solar cells are used to provide electric power in remote locations including space satellites; because they have no moving parts that could require service or fuels that would require replenishment, solar cells are ideal for providing power in space. See illustration on following page.