inhibition In enzymology, a phenomenon in which a compound (an inhibitor), usually similar in structure to the substance on which an enzyme acts (substrate), interacts with the enzyme so that the resulting complex cannot undergo the usual reaction or cannot form the usual product. The inhibitor may function by combining with the enzyme at the site at which the reaction usually occurs (competitive inhibition) or at another site (non¬ competitive inhibition). See also allosteric control, feedback inhibition,
REPRESSION.
inhibition In psychology, the conscious or unconscious suppression of free or spontaneous thought or behaviour through the operation of psycho¬ logical impediments, including internalized social controls. Inhibition serves useful social functions such as protecting oneself and others from harm and enabling the delay of gratification from pleasurable activities. Both extreme lack of inhibition and excessive inhibition can be personally destructive. Inhibition also plays an important role in learning, since an organism must learn to restrain certain instinctual behaviours or previously learned patterns in order to master new patterns. In physiological psychol¬ ogy, inhibition refers to the suppression of neural electrical activity.
initiation See rite of passage, secret society
injunction In civil proceedings, a court order compelling a party to do or to refrain from doing a specified act. It is an equitable remedy for harm for which no adequate remedy exists in law. Thus it is used to prevent a future harmful action (e.g., disclosing confidential information, institut¬ ing a national labour strike, or violating a group’s civil rights) rather than to compensate for an injury that has already occurred. It also provides relief from harm for which an award of money damages is not a satisfac¬ tory solution. A defendant who violates an injunction may be cited for contempt. See also equity.
ink Fluid or paste of various colours (usually black or dark blue) used for writing and printing, composed of a pigment or dye in a liquid “vehicle.” Early inks used lampblack (a form of carbon) or coloured juices, extracts, or suspensions of plant, animal, and mineral substances. Modern writing inks usually contain ferrous sulfate (see iron) with a small amount of an acid; on paper, they darken and bond, becoming permanent. Coloured and washable inks usually contain soluble synthetic dyes. Printing inks are formulated for various requirements (including colour, opacity, fade resis¬ tance, pliability, odourlessness, drying behaviour, and health and environ¬ mental safety) for uses in offset, letterpress, screen, ink-jet, laser, and other printing.
Inkatha \in-'ka-to\ Freedom Party Political party in South Africa consisting largely of the Zulu. It originated in 1924 as a cultural move¬ ment under King Dinizulu. His grandson, Mangosuthu G. Buthelezi, revived it in 1974 as a political party after breaking with the African National Congress (ANC). Under Buthelezi, Inkatha advocated a struggle against apartheid but a willingness to accept power-sharing arrangements short of majority rule. From the late 1980s Inkatha and ANC followers were regularly involved in bloody clashes with strong ethnic (Zulu v. non-Zulu) overtones. In 1991 the white South African government admit¬ ted that it had secretly subsidized Inkatha.
Inland Passage See Inside Passage
Inn River Major tributary of the Danube River. It rises in Switzerland and flows 317 mi (510 km) northeast across western Austria and southern Germany. Its Swiss section is called the Engadin. In Austria it travels past Innsbruck and along the Bavarian Alps, entering Germany in Bavaria, where it flows northeast. It forms part of the Austro-German border as it joins the Danube at Passau.
inner ear or labyrinth of the ear Part of the ear containing organs of hearing and equilibrium. The bony labyrinth has three sections (semi¬ circular canals, vestibule, and cochlea); within each structure is a corre¬ sponding part of the membranous labyrinth (semicircular ducts, two saclike structures in the vestibule, and cochlear duct). Sound vibrations are transmitted from the middle ear through the membrane-covered oval window to fluid in the snail-shell-shaped cochlea, whose motion stimu¬ lates hair cells in the cochlea. The hair cells trigger nerve impulses that travel to the brain, which interprets them as sound. The vestibule and semicircular canals also have organs with hair cells. Those in the vesti¬ bule indicate the head’s position with respect to the rest of the body (see proprioception). The three semicircular canals, at right angles to each other, signal motion of the head in three-dimensional space. Continued stimu¬ lation after motion stops causes a mismatch with visual input, experienced as dizziness or motion sickness.
Inner Mongolia Chinese Nei Mongol Vna-'muq-'goB or Nei- meng-ku Vna-'moq-'gtA Autonomous region (pop., 2002 est.: 23,790,000), China. Stretching some 1,800 mi (2,900 km) across north- northeastern China, it has an area of 454,600 sq mi (1,177,500 sq km); its capital is Hohhot. Mongols and Chinese make up the bulk of the popu¬ lation, most of which is concentrated in the agricultural belt near the Huang He (Yellow River). Inner Mongolia is an inland plateau lying at an elevation of about 3,300 ft (1,000 m); it is fringed by mountains and valleys. Its northern portion lies within the Gobi Desert, and its southern border is partly marked by the Great Wall. Inner Mongolia was separated from Mongolia (Outer Mongolia) in 1912 and was established as an autonomous region in 1947. Its harsh climate restricts intensive agricul¬ ture; some industrial development has occurred there.
inner product space In mathematics, a vector space or function space in which an operation for combining two vectors or functions (whose result is called an inner product) is defined and has certain properties. Such spaces, an essential tool of functional analysis and vector theory, allow analysis of classes of functions rather than individual functions. In math¬ ematical analysis, an inner product space of particular importance is a Hil¬ bert space, a generalization of ordinary space to an infinite number of dimensions. A point in a Hilbert space can be represented as an infinite sequence of coordinates or as a vector with infinitely many components. The inner product of two such vectors is the sum of the products of cor¬ responding coordinates. When such an inner product is zero, the vectors are said to be orthogonal (see orthogonality). Hilbert spaces are an essen¬ tial tool of mathematical physics. See also David Hilbert.
Innes, Michael See J.I.M. Stewart
Valpin^on Bather, oil painting by Jean- Auguste-Dominique Ingres, 1808; in the Louvre, Paris.
GIRAUDON/ART RESOURCE
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Inness ► insanity I 943
Inness, George (b. May 1, 1825, Newburgh, N.Y., U.S.—d. Aug. 3, 1894, Bridge of Allen, Stirling, Scot.) U.S. landscape painter. He was largely self-taught. His early paintings were influenced by the Hudson River school. He spent much time in Europe studying the works of the Barbizon school, and from c. 1855 to 1874 he developed the luminous, atmospheric quality for which his landscapes are known. The influence of Camille Corot is evident in his intimately rendered images of far- reaching expanses. His later works are marked by the ascendancy of colour over form. His sense of mysticism intensified over time, and the pictures tended to dissolve into shimmering colour with no outlines or formal construction. See also luminism.