Vavilov \vov-'ye-bf\, Nikolay (Ivanovich) (b. Nov. 25, 1887, Mos¬ cow, Russian Empire—d. Jan. 26, 1943, Saratov, Russia, U.S.S.R.) Rus¬ sian plant geneticist. Through expeditions to many parts of the world, Vavilov amassed an immense plant collection and conceived the theory that a cultivated plant’s centre of origin would be found in the region in which wild relatives of the plant showed maximum adaptiveness. He eventually proposed 13 world centres of plant origin. Though widely con¬ sidered one of the greatest specialists in botanical populations, he was publicly condemned by Trofim Lysenko at successive plant-breeding con¬ gresses (1934-39) as peddling “Mendelist-Morganist genetics” (see Gre¬ gor Mendel; Thomas Hunt Morgan), and he died in a concentration camp.
vCard Electronic business card that automates the exchange of personal information typically found on a traditional business card. The vCard is a file that contains the user’s basic business or personal data (name, address, phone number, URLs, etc.) in a variety of formats such as text, graphics, video clips, and audio clips. It can be attached to an e-mail or exchanged between computers or on the Internet, where, for example, the user can drag-and-drop his or her vCard to a registration or order form on a Web page so that it can automatically complete the form. It is used in such applications as voice mail, Web browsers, call centres, video con¬ ferencing, pagers, faxes, and smart cards.
VCR in full videocassette recorder Electromechanical device that records, stores on a videotape cassette, and plays back on a TV set recorded images and sound. The first commercial VCRs were marketed by Sony Corp. in 1969. VCRs are used to record broadcast TV programs for later viewing and to play commercially recorded cassettes. They have from two to seven tape heads that read and inscribe video and audio tracks on mag¬ netic tape. Home movies can be made with a camcorder system, a VCR connected to a simple video camera.
veal Meat of young calves. It is usually pale grayish white in colour, firm and fine-grained, with a velvety texture. Calves bred to yield veal are usually raised indoors under controlled temperatures and intensively fed on milk, high-protein calf meal, or both. Herbaceous foods are excluded, which results in an iron deficiency that produces the desirable light colour in the meat. In recent decades, animal-rights groups have denounced calf farming as cruel.
barrel vault
Four common types of vault. A barrel vault (also called a cradle vault, tunnel vault, or wagon vault) has a semicircular cross section. A groin (or cross) vault is formed by the perpendicular intersection of two barrel vaults. A rib (or ribbed) vault is sup¬ ported by a series of arched diagonal ribs that divide the vault's surface into pan¬ els. A fan vault is composed of concave sections with ribs spreading out like a fan.
© MERRIAM-WEBSTER INC.
Veblen Vveb-bn\, Thorstein (Bunde) (b. July 30, 1857, Manitowoc county, Wis., U.S.—d. Aug. 3, 1929, near Menlo Park, Calif.) U.S. econo¬ mist. He grew up in Minnesota and earned a Ph.D. in philosophy from Yale University. Although he taught economics at the University of Chi¬ cago and other universities, he was unable to keep any position for long because of his unconventional ideas and the disorder in his personal life. In 1899 he published his classic work The Theory of the Leisure Class, which applied Darwin’s evolutionary theories to the study of modem economic life, highlighting the competitive and predatory nature of the business world. With dry humour he identified the markers of American social class, and he coined the term “conspicuous consumption” to describe the display of wealth made by the upper class. His reputation was highest in the 1930s, when the Great Depression was seen as a vin¬ dication of his criticism of the business system.
vector In mathematics, a quantity characterized by magnitude and direc¬ tion. Some physical and geometric quantities, called scalars, can be fully defined by a single number specifying their magnitude in suitable units of measure (e.g., mass in grams, temperature in degrees, time in seconds). Quantities like velocity, force, and displacement must be specified by a magnitude and a direction. These are vectors. A vector quantity can be visualized as an arrow drawn in a specific direction, whose length is equal to the magnitude of the quantity represented. A two-dimensional vector is specified by two coordinates, a three-dimensional vector by three coor¬ dinates, and so on. Vector analysis is a branch of mathematics that explores the utility of this type of representation and defines the ways such quantities may be combined. See also vector operations.
vector operations Extension of the laws of elementary algebra to vectors. They include addition, subtraction, and three types of multipli¬ cation. The sum of two vectors is a third vector, represented as the diago¬ nal of the parallelogram constructed with the two original vectors as sides. When a vector is multiplied by a positive scalar (i.e., number), its mag¬ nitude is multiplied by the scalar and its direction remains unchanged (if the scalar is negative, the direction is reversed). The multiplication of a vector a by another vector b leads to the dot product, written a • b, and the cross product, written a x b. The dot product, also called the scalar product, is a scalar real number equal to the product of the lengths of vectors a (|a|) and b (|b|) and the cosine of the angle (0) between them: a ■ b = |a| |b| cos 0. This equals zero if the two vectors are perpendicular (see orthogonality). The cross product, also called the vector product, is a third vector (c), perpendicular to the plane of the original vectors. The magnitude of c is equal to the product of the lengths of vectors a and b and the sine of the angle (0) between them: |c| = |a| |b| sin 0. The asso¬ ciative law and commutative law hold for vector addition and the dot prod¬ uct. The cross product is associative but not commutative.
vector space In mathematics, a collection of objects called vectors, together with a field of objects (see field theory), known as scalars, that satisfy certain properties. The properties that must be satisfied are: (1) the set of vectors is closed under vector addition; (2) multiplication of a vec¬ tor by a scalar produces a vector in the set; (3) the associative law holds for vector addition, u + (v + w) = (u + v) + w; (4) the commutative law holds for vector addition, u + v = v + u; (5) there is a 0 vector such that v + 0 = v; (6) every vector has an additive inverse (see inverse function), v + (-v) = 0; (7) the distributive law holds for scalar multiplication over vector addition, n(u + v) = mi + n\ (8) the distributive law also holds for vector multiplication over scalar addition, (m + n)\ = mv + n\ (9) the associative law holds for scalar multiplication with a vector, ( mn)\ = m ( nv ); and (10) there exists a unit vector 1 such that lv = v. The set of all polynomials in one variable with real coefficients is an example of a vector space.
Ved-ava Vva-da-va\ Divine ruler of the waters and their bounty, com¬ mon to several Baltic and Finno-Ugric peoples traditionally dependent on fishing. She was also responsible for promoting fertility in humans and in livestock. In appearance, she resembled a mermaid, having long hair, large breasts, and a fishlike lower body. Fishermen sacrificed to her the first of their catch and observed numerous taboos while fishing. Seeing Ved-ava generally boded misfortune, most often drowning. She has been regarded as the spirit of a drowned person or simply as a personification of the water itself.
Veda \'va-do\ Any of a group of sacred hymns and verses composed in archaic Sanskrit, probably in the period 1500-1200 bc. Together they form a body of liturgical literature that grew up around the cult of the soma
© 2006 Encyclopaedia Britannica, Inc.
1992 I Vedanta ► Velazquez
ritual. They extol the hereditary deities that personified various natural and cosmic phenomena. The entire corpus of Vedic literature, including the Upanishads, was considered the product of divine revelation. The Vedas were handed down orally for many generations before being committed to writing. Even today, several are recited with intonation and rhythm associated with the early days of Vedic religion. See also Rig Veda, Vedanta.