Dennison, Aaron Lufkin (b. March 6, 1812, Freeport, Mass., U.S.—d. Jan. 9, 1895, Birmingham, Eng.) U.S. watch manufacturer. After studying the methods used at the Springfield Armory, he mastered the tech¬ nical difficulties of machine production of small parts, set up a factory in Waltham, Mass., in 1850, and began to produce the first inexpensive factory-made watches with interchangeable parts. His introduction of machinery into the manufacture of paper boxes and other paper products resulted in the founding of the Dennison Manufacturing Co. He is regarded as the father of American watchmaking.
density Mass of a unit volume of a material substance. It is calculated by dividing an object’s mass by its volume. In the International System of Units, and depending on the units of measurement used, density can be expressed in grams per cubic centimetre (g/cm 3 ) or kilograms per cubic
metre (kg/m 3 ). The expression “particle density” refers to the number of particles per unit volume, not to the density of a single particle. See also SPECIFIC GRAVITY.
density current Any current in either a liquid or a gas that is kept in motion by the force of gravity acting on small differences in density. A density difference can exist between two fluids or between different parts of the same fluid. Density currents flow along ocean and lake bottoms, because the water entering is colder, saltier, or contains more suspended sediment and thus is denser than the surrounding water. Density currents are a factor in water pollution, as the industrial discharge of large amounts of polluted or heated water can generate density currents that affect neigh¬ bouring human or animal communities.
density function In statistics, a function whose integral is calculated to find probabilities associated with a continuous random variable (see continuity, probability theory). Its graph is a curve above the horizontal axis that defines a total area, between itself and the axis, of 1. The percentage of this area included between any two values coincides with the prob¬ ability that the outcome of an observation described by the density func¬ tion falls between those values. Every random variable is associated with a density function (e.g., a variable with a normal distribution is described by a bell curve).
dentistry Profession concerned with the teeth and mouth. It includes repair or removal of decayed teeth, straightening and adjustment of teeth for proper occlusion, and design, manufacture, and fitting of false teeth and other prosthetic devices. X-rays are used to show conditions not vis¬ ible on examination. Using local anesthesia, caries in teeth are drilled to remove diseased areas and filled with various materials. Decay that reaches a tooth’s root risks infection of the nerve and requires root-canal surgery. Teeth that must be extracted are replaced by crowns for single teeth and full or partial dentures or implants for more. Dentists also edu¬ cate patients on oral hygiene, examine and clean teeth, and apply fluo¬ ride compounds for decay resistance.
D'Entrecasteaux V.don-tro-'kas-toX Islands Island group, Papua New Guinea. Located in the South Pacific Ocean, the group includes Nor- manby, Fergusson, and Goodenough islands and many islets, atolls, and reefs. Most are volcanic, precipitous, and forested. They have a combined land area of 1,213 sq mi (3,142 sq km). They were named by the French navigator Bruni d’Entrecasteaux in 1793. The chief settlement is Dobu, located on an islet between Normanby and Fergusson.
Denver City (pop., 2000: 554,636), capital of Colorado, U.S. On the South Platte River just east of the Rocky Mountains, its elevation of 5,280 ft (1,609 m) gives it the nickname “Mile High City.” An early stopping place for Indians and trappers, it was settled in 1858 as St. Charles, abruptly renamed Denver City (the “city” was eventually dropped), and combined with the rival town of Auraria in 1860, becoming the territo¬ rial capital as Denver City in 1867. The 1870s and ’80s saw a silver boom that ended in 1893, but new gold discoveries helped prevent a major decline. Modem Denver, a transportation, industrial, and commercial hub, has one of the nation’s largest livestock markets. It is a major centre for winter sports, with many ski areas in the vicinity. The Denver branch of the U.S. Mint (opened 1906) produces about 50% of U.S. coinage and is the nation’s second largest gold depository.
deontic logic \de-'an-tik\ Branch of modal logic that studies the per¬ mitted, the obligatory, and the forbidden, which are characterized as deon¬ tic modalities (Greek, deontos : “of that which is binding”). It seeks to systematize the abstract, purely conceptual relations between propositions in this sphere, such as the following: If an act is obligatory, then its per¬ formance must be permitted and its omission forbidden. In given circum¬ stances, every act is such that either it or its omission is permitted. Modal logic leaves to substantive disciplines such as ethics and law the concrete questions of what specific acts or states of affairs are to be forbidden, per¬ mitted, or the like.
deontological ethics Ethical theories that maintain that the moral rightness or wrongness of an action depends on its intrinsic qualities, and not (as in consequentialism) on the nature of its consequences. Deonto¬ logical ethics holds that at least some acts are morally wrong in them¬ selves (e.g., lying, breaking a promise, punishing the innocent, murder). It often finds expression in slogans such as “Duty for duty’s sake.” Deon¬ tological theories are often formulated in such a way that the rightness of an action consists in its conformity to a moral rule or command, such as
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534 I Depardieu ► derivatives
“Do not bear false witness.” The most important exponent of deontolog- ical ethics is Immanuel Kant. See also categorical imperative.
Depardieu \d9-par-'dyoe\, Gerard (b. Dec. 27, 1948, Chateauroux, France) French film actor. He made his film debut in 1965 and played minor parts until his performance in Going Places (1974) brought him a major role in Bernardo Bertolucci’s 1900 (1976). He became French cin¬ ema’s top male star in the 1980s and also made films elsewhere in Europe and in the U.S. Noted for a screen image that combined sensitivity with masculine strength, he delivered compelling performances in The Last Metro (1980), The Return of Martin Guerre (1981), Jean de Florette (1986), Matron of the Spring (1986), Cyrano de Bergerac { 1990), and Tous les matins du monde (1992).
department store Retail establishment that sells a wide variety of goods. These usually include ready-to-wear apparel and accessories, yard goods and household textiles, housewares, furniture, electrical appliances, and accessories. In addition to departments (supervised by managers and buyers) for the various categories of goods, there are departmental divi¬ sions to handle, for example, merchandising, advertising, service, accounting, and financial strategy. The Bon Marche in Paris, which began as a small shop in the early 19th century, is often considered the first department store. The first U.S. department store chains—J.C. Penney and Sears, Roebuck and Co.— date to the 1920s. See also Harrods.
dependency In international relations, a weak state dominated by or under the jurisdiction of a more powerful state but not formally annexed by it. Examples include American Samoa (U.S.) and Greenland (Denmark). The dominant state may control certain of its affairs, such as defense, for¬ eign relations, and internal security, and allow it autonomy in domestic affairs such as education, health, and infrastructural development. In the 1960s and ’70s the term referred to an approach to understanding third- world development that emphasized the constraints imposed by the glo¬ bal political and economic order.