open-hearth process: see steel.

open-end investment company: see mutual fund.

open-chain compound: see aliphatic compound.

open shop: see closed shop and open shop.

open enrollment, a policy of admitting to college all high-school graduates in an effort to provide a higher education for all who desire it. To critics it means an inevitable lowering of standards as a considerable effort must be devoted to development of basic skills. The most ambitious programs of open enrollment in the United States have been undertaken in California and New York City. Under California's system, codified in 1960, high-school graduates in the top eighth of their class may attend a Univ. of California campus. Those in the top third qualify for a state university. All the rest may attend a two-year community college. New York City's plan, begun in 1970, guarantees every high-school graduate, academic or vocational, a place in a city college. In the 1980s and 90s many educational institutions partially reversed such policies and tightened admission requirements.

open education, also known as open classroom, type of educational reform. The central tenet of this informal system is that children want to learn and will do so naturally if left to their own initiative. The open classroom is marked by decentralized learning areas, freedom of movement from area to area and even from room to room, group and individual student activities, and unstructured periods of study. Open education is concerned with erasing the formalized roles of student and teacher; instruction itself is rarely given to more than two or three pupils at a time and the same material is hardly ever presented to the class as a whole. Growing out of principles developed at British infant and junior schools, it first became popular in American elementary schools during the late 1960s. Many of its ideas were enunciated earlier by those involved in the progressive education movement.

open cluster, see star cluster.

closed shop and open shop. The term "closed shop" is used to signify an establishment employing only members of a labor union. The union shop, a closely allied term, indicates a company where employees do not have to belong to a labor union when hired but are required to join within a specified period of time in order to keep their jobs. An open shop, strictly speaking, is one that does not restrict its employees to union members. Among European workers the issue of the closed shop has not been so sharply contested as in the United States, where since c.1840 the closed-shop policy had been adopted by most labor unions. Judicial decisions from 1850 to 1898 usually decided that strikes held to achieve a closed shop were illegal. For a period of time after the passage of the Wagner Act (see National Labor Relations Board) in 1935, decisions of the federal courts tended to uphold the legality of the closed shop. Many states, however, either by legislation or by court decision, have banned the closed shop. In 1947 the Taft-Hartley Labor Act declared the closed shop illegal and union shops were also prohibited unless authorized in a secret poll by a majority of the workers; it was amended (1951) to allow union shops without a vote of the majority of the workers. Thereafter, a campaign was begun by business leaders in certain industries to have so-called right-to-work laws enacted at the state level. More than one third of the states passed such laws, the effect being to declare the union shop illegal. It is argued in favor of the closed shop that unions can win a fair return for their labor only through solidarity, since there is always—except in wartime—an oversupply of labor; and that, since all employees of a plant share in the advantages won through collective bargaining, all workers should contribute to union funds. Arguments in favor of the open shop are that forcing unwilling workers to pay union dues is an infringement of their rights; that union membership is sometimes closed to certain workers or the initiation fee so high as to be an effective bar to membership; and that employers are deprived of the privilege of hiring competent workers or firing incompetent ones.

Open University, headquartered at Milton Keynes, England; founded 1969 as the Univ. of the Air. In 1971 a distance learning program was begun that consists of correspondence courses integrated with television and radio broadcasts, residential summer schools, and a counseling and tutorial service that operates through a network of regional offices and local study centers. Students (over 160,000) are usually over 21, working full-time, and studying in their spare time. The university has faculties of arts, education, management, mathematics, science, social sciences, and technology. It has served as the prototype for similar programs throughout the world.

Open Door, maintenance in a certain territory of equal commercial and industrial rights for the nationals of all countries. As a specific policy, it was first advanced by the United States, but it was rooted in the typical most-favored-nation clause of the treaties concluded with China after the Opium War (1839-42). Although the Open Door is generally associated with China, it also received recognition at the Berlin Conference of 1885, which declared that no power could levy preferential duties in the Congo basin.

Development of the Policy

In the 1890s, the United States had become an East Asian power through the acquisition of the Philippine Islands, and when the partition of China by the European powers and Japan seemed imminent, the U.S. government strove to preserve equal industrial and commercial privileges. Secretary of State John Hay sent (1899) notes to the major powers (France, Germany, Great Britain, Italy, Japan, and Russia), asking them to declare formally that they would uphold Chinese territorial and administrative integrity and would not interfere with the free use of the treaty ports within their spheres of influence in China. In replying, each nation evaded Hay's request, taking the position that it could not commit itself until the other nations had complied. However, in Mar., 1900, Hay announced that the powers had granted consent to his request. Only Japan challenged this declaration, and the Open Door became an international policy. After the Boxer Uprising, Hay dispatched (1900) a similar circular note.

Violations and the End of the Policy

Two years later, the U.S. government protested that Russian encroachment in Manchuria was a violation of the Open Door. When Japanese replaced Russian influence in S Manchuria after the Russo-Japanese War (1904-5) the Japanese and U.S. governments pledged to maintain a policy of equality in Manchuria. In finance, American efforts to preserve the Open Door led (1909) to the formation of an international banking consortium through which all Chinese railroad loans would be made. The United States withdrew in 1913, asserting that the consortium violated Chinese administrative integrity.

The next violation of the Open Door policy occurred in 1915, when Japan presented to China the Twenty-one Demands. That incident led (1917) to another exchange of notes between the United States and Japan in which there were renewed assurances that the Open Door would be respected, but that the United States recognized Japan's special interests in China. The Open Door principle had been further weakened by a series of secret treaties (1917) between Japan and the Allies, which promised Japan the German possessions in China.

The increasing disregard of the Open Door was a main reason for the convocation of the Conference on the Limitation of Armament (1921-22) in Washington, D.C. As a result of the conference, the Nine-Power Treaty, guaranteeing the integrity and independence of China and reaffirming the Open Door principle, was signed by the United States, Great Britain, Japan, France, Italy, the Netherlands, Portugal, China, and Belgium. With the Japanese seizure (1931) of Manchuria and the creation of Manchukuo, however, the Open Door received its greatest reverse.

After World War II, China's position as a sovereign state was recognized. No nation, therefore, had the right or capacity to carve out spheres of influence or to attempt to exclude other states from trade, and the Open Door policy ceased to exist.

Any of the purchases and sales of government securities and commercial paper by a central bank in an effort to regulate the money supply and credit conditions. Open market operations can also be used to stabilize the prices of government securities. When the central bank buys securities on the open market, it increases the reserves of commercial banks, making it possible for them to expand their loans and investments. It also increases the price of government securities, equivalent to reducing their interest rates, and decreases interest rates generally, thus encouraging investment. If the central bank sells securities, the effects are reversed. Open market operations are usually performed with short-term government securities such as treasury bills.

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or Siemens-Martin process

Steelmaking technique that for most of the 20th century accounted for most steel made in the world. William Siemens made steel from pig iron in a reverberatory furnace of his design in 1867. The same year the French manufacturer Pierre-Émile Martin (1824–1915) used the idea to produce steel by melting wrought iron with steel scrap. Siemens used the waste heat given off by the furnace: he directed the fumes from the furnace through a brick checkerwork, heating it to a high temperature, and then used the same path to introduce air into the furnace; the preheated air significantly increased the flame temperature. The open-hearth process furnace (which replaced the Bessemer process) has itself been replaced in most industrialized countries by the basic oxygen process and the electric furnace. Seealso reverberatory furnace.

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Any surgical procedure opening the heart and exposing one or more of its chambers, most often to repair valve disease or correct congenital heart malformations (see congenital heart disease). Invention of the heart-lung machine (see artificial heart), which allows the heart to be stopped during surgery, made it possible. The first successful open-heart surgery was performed in the U.S. in 1953 by John H. Gibbon, Jr., to close an atrial septal defect.

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