autograph Any manuscript handwritten by its author; in common usage, a handwritten signature. Aside from its value as a collector’s item, an early or corrected draft of a work may show its stages of composition or “correct” final version. The earliest autograph signature of a famous person is probably the Cid’s, dated 1096. There exist autographs of most of the great Renaissance figures, including Leonardo da Vinci, Michelan¬ gelo, and Ludovico Ariosto. Since the 1 8th century, autograph material of notable people in the arts, sciences, or public life has been more abundant.
autoimmune disease Any disease caused by an immune response (see immunity) against antigens in the tissues of one’s own body. The immune system has two known ways to prevent such a response: destruction of lymphocytes in the thymus before they leave to attack one’s own tissues and loss of ability to react to their target antigens by any such cells that do leave the thymus. Autoimmune diseases arise when these mechanisms fail and lymphocytes destroy host tissues; examples include type 1 diabetes mellitus, systemic lupus erythematosus, pernicious anemia, and rheumatoid arthritis. Treatment may replace the function of the affected tissue (e.g., insulin therapy for diabetes) or suppress the immune system (see immun¬ osuppression). Allergy is another type of autoimmune reaction.
automata fo-'ta-mo-toX theory Body of physical and logical prin¬ ciples underlying the operation of any electromechanical device (an automaton) that converts information input in one form into another, or into some action, according to an algorithm. Norbert Wiener and Alan M. Turing are regarded as pioneers in the field. In computer science, automata theory is concerned with the construction of robots (see robotics) from basic building blocks of automatons. The best example of a general automaton is an electronic digital computer. Networks of automata may be designed to mimic human behaviour. See also artificial intelligence; Turing MACHINE.
automation Term coined about 1946 by a Ford Motor Co. engineer, used to describe a wide variety of systems in which there is a significant substitution of mechanical, electrical, or computerized action for human effort and intelligence. In general usage, automation can be defined as a technology concerned with performing a process by means of pro¬ grammed commands combined with automatic feedback control (see con¬ trol system) to ensure proper execution of the instructions. The resulting system is capable of operating without human intervention.
automatism Xo-'ta-mo-.tiz-omX Method of painting or drawing in which conscious control over the movement of the hand is suppressed so that the subconscious mind may take over. For some Abstract Expression¬ ists, such as Jackson Pollock, the automatic process encompassed the entire process of composition. The Surrealists, having once achieved an interesting image or form by automatic or chance means, exploited the technique with fully conscious purpose. See also Abstract Expressionism, ACTION PAINTING, SURREALISM.
automaton Xo-'ta-mo-tonX Mechanical object, either functional (such as a clock) or decorative (such as a miniature singing bird), that is self- operating. Devices set in motion by water, falling weights, and steam were in use in the 1st century. Decorative mechanical objects were made for
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ecclesiastical use and table ornaments in the Middle Ages and Renais¬ sance. Spectacular fountains and waterworks can be seen in 16th-century Italian gardens; elaborate mechanical devices (such as the chess-playing Turk) were popular in the 18th-19th century. Except for some works by Carl Faberge, the production of expensive automatons virtually ceased by the 20th century.
automobile Four-wheeled automotive vehicle designed for passenger transportation, commonly propelled by an internal combustion engine using a volatile fuel. The modem automobile consists of about 14,000 parts, divided into several structural and mechanical systems. These include the steel body, containing the passenger and storage space, which sits on the chassis or steel frame; the internal combustion gasoline engine, which powers the car by means of a transmission; the steering and braking sys¬ tems, which control the car’s motion; and the electrical system, which includes a battery, alternator, and other devices. Subsystems involve fuel, exhaust, lubrication, cooling, suspension, and tires. Though experimental vehicles were built in the 18th and mid-19th century, not until the 1880s did Gottlieb Daimler and Karl Benz in Germany begin separately to manu¬ facture cars commercially. In the U.S., James and William Packard and Ransom Olds were among the first auto manufacturers, and by 1898 there were 50 U.S. manufacturers. Some early cars operated by steam engine, such as those made from c. 1902 by Francis E. and Freelan O. Stanley. The internal combustion engine was used by Henry Ford when he introduced the Model T in 1908; Ford would soon revolutionize the industry with his use of the assembly line. In the 1930s European manufacturers began to make small, affordable cars such as the Volkswagen. In the 1950s and ’60s, U.S. automakers produced larger, more luxurious cars with more automatic features. In the 1970s and ’80s Japanese manufacturers exported their small, reliable, fuel-efficient cars worldwide, and their increasing popularity spurred U.S. automakers to produce similar models. See also axle, brake, bus, carburetor, electric automobile, fuel injection, motor¬ cycle, TRUCK.
automobile racing Sport practiced in a variety of forms on roads, tracks, or closed circuits. It includes Grand Prix racing, speedway racing (including the Indianapolis 500), stock-car racing, sports-car racing, drag racing, midget-car racing, and karting, as well as hill climbs and rally driv¬ ing. The International Motor Sports Hall of Fame is located in Talladega, Ala., U.S. There is no central governing body for automobile racing in the U.S. as there is in most other countries.
autonomic \,6t-9-'nam-ik\ nervous system Part of the nervous sys¬ tem that is not under conscious control and that regulates the internal organs. It includes the sympathetic, parasympathetic, and enteric nervous systems. The first, which connects the internal organs to the brain via spi¬ nal nerves, responds to stress by increasing heart rate and blood flow to the muscles and decreasing blood flow to the skin. The second comprises the cranial nerves and the lower spinal nerves, which increase digestive secretions and slow the heartbeat. Both have sensory fibres that send feedback on the condition of internal organs to the central nervous sys¬ tem, information that helps maintain homeostasis. The third division, embedded in the walls of the stomach and intestines, controls digestive movement and secretions. See illustration opposite.
autopsy \'6-,tap-se\ or necropsy or postmortem Dissection and examination of a dead body to determine cause of death and learn about disease processes in ways that are not possible with the living. Autopsies have contributed to the development of medicine since at least the Middle Ages. Beyond revealing causes of individual deaths, autopsy is crucial to the accuracy of disease and death statistics, the education of medical stu¬ dents, the understanding of new and changing diseases, and the advance¬ ment of medical science.
Autry, (Orvon) Gene (b. Sept. 29, 1907, Tioga, Texas, U.S.—d. Oct. 2, 1998, North Hollywood, Calif.) U.S. actor and singer. He made his debut on a local radio show in 1928, hosting his own radio program from 1931. His first film. In Old Santa Fe (1934), launched his career as a cow¬ boy actor. Known as “the Singing Cowboy,” he starred in 18 movies, end¬ ing with Alias Jesse James (1959). His recordings, including “Rudolph the Red-Nosed Reindeer” (1949), sold millions of copies. The televised Gene Autry Show ran from 1950 to 1954.