program trading, a form of securities trading, also known as index arbitrage. Program traders exploit the price discrepancies between indexes of stocks and futures contracts by using sophisticated computer models to hedge positions. Program trading (also called computer-assisted trading) arose with the advent of computer and telecommunication technologies, whereby trade in different markets could be monitored simultaneously and manipulated accordingly. Because the size of the transactions often caused massive jolts in the stock market, many concluded that program trading was largely responsible for the 500-point drop in the Dow Jones Industrial Average on Oct. 19, 1987. During the economic recession that followed, the New York Stock Exchange put new restrictions on computerized trading, and many companies refused to do business with any brokerage house that engaged in program trading. With the unprececented growth of the stock market in the later 1990s, program trading saw a resurgence in some trading houses.

program music Instrumental music of the 19th and 20th cent. that endeavors to arouse mental pictures or ideas in the thoughts of the listener—to tell a story, depict a scene, or impel a mood. Moussorgsky's Pictures at an Exhibition, intended by the composer as program music, might be contrasted with a symphony of Brahms, which is considered as absolute music. It is so called because it relies on a "program" (an expanatory text or narrative) to explain its extra-musical associations. Examples are the symphonic poems of Liszt, and Sorceror's Apprentice by Dukas.

computer program, a series of instructions that a computer can interpret and execute; programs are also called software to distinguish them from hardware, the physical equipment used in data processing. These programming instructions cause the computer to perform arithmetic and logical operations or comparisons (and then take some additional action based on the comparison) or to input or output data in a desired sequence. In conventional computing the operations are executed sequentially; in parallel processing the operations are allocated among multiple processors, which execute them concurrently and share the results. Programs are often written as a series of subroutines, which can be used in more than one program or at more than one point in the same program.

Systems programs are those that control the operation of the computer. Chief among these is the operating system—also called the control program, executive, or supervisor—which schedules the execution of other programs, allocates system resources, and controls input and output operations. Processing programs are those whose execution is controlled by the operating system. Language translators decode source programs, written in a programming language, and produce object programs, which are in machine language and can be understood by the computer. These include assemblers, which translate symbolic languages that have a one-to-one relationship with machine language; compilers, which translate an algorithmic- or procedural-language program into a machine-language program to be executed at a later time; and interpreters, which translate source-language statements into object-language statements for immediate execution. Other processing programs are service or utility programs, such as those that "dump" computer memory to external storage for safekeeping and those that enable the programmer to "trace" program execution, and application programs, which perform business and scientific functions, such as payroll processing, accounts payable and receivable posting, word processing, and simulation of environmental conditions.

United Nations Development Program (UNDP), agency of the United Nations, established in 1965 to unify the operations of the Expanded Program of Technical Assistance and the United Nations Special Fund, which continued as separate components of UNDP until full unification in 1971. The UNDP is a major source of technical assistance in developing countries, with most of its grants being in the form of consultants' services, equipment, and fellowships for advanced study abroad. Thousands of projects in areas as diverse as resource planning, training institutes, the application of modern technology to development, and the building of the economic and social infrastructure are supported by the UNDP. It also administers UN special purpose funds for resource exploration, combating desertification, technology development and volunteers, and works with UN-associated agencies involved in development activities. It is funded by voluntary contributions from UN members.

Point Four program, U.S. foreign aid project aimed at providing technological skills, knowledge, and equipment to poor nations throughout the world. The program also encouraged the flow of private investment capital to these nations. The project received its name from the fourth point of a program set forth in President Truman's 1949 inaugural address. In the cold war the U.S. government used Point Four to win support from uncommitted nations. From 1950 until 1953, Point Four aid was administered by the Technical Cooperation Administration, a separate unit within the Dept. of State. During the administration of President Eisenhower it was integrated into the overall foreign aid program.

National Marine Sanctuary Program, federally owned marine and Great Lakes reserves, administered by the National Oceanic and Atmospheric Administration (NOAA). The program consists of 13 marine sanctuaries totaling over 18,000 sq mi (46,632 sq km) in eight states and American Samoa. Four of the areas are on the California coast, including the largest, at Monterey Bay. The Florida Keys and Hawaii also have large sanctuaries. Founded in 1972, the program was set up to protect those marine and Great Lakes areas of special significance, such as the only barrier reef in the United States, which is in the Florida Keys. The first sanctuary, encompassing the sunken remains of the Civil War ironclad USS Monitor (see Monitor and Merrimack), off the coast of North Carolina, was designated in 1975. Education and research are important aspects of the program; oil drilling and salvaging are prohibited in the sanctuaries.

The National Estuarine Research Reserve System, also established in 1972 and managed by NOAA, has 25 reserves covering more than 1 million acres (405,000 hectares) in 17 states and Puerto Rico. The reserves are representative of the various regions and estuarine types found in the United States and its territories.

Mercury space program: see space exploration.

Mariner space program: see space exploration.

Gemini space program: see space exploration.

European Recovery Program: see Marshall Plan.

Erlangen program: see geometry.

Apollo space program: see space exploration.

Concept of government in which the state plays a key role in protecting and promoting the economic and social well-being of its citizens. It is based on the principles of equality of opportunity, equitable distribution of wealth, and public responsibility for those who lack the minimal provisions for a good life. The term may be applied to a variety of forms of economic and social organization. A basic feature of the welfare state is social insurance, intended to provide benefits during periods of greatest need (e.g., old age, illness, unemployment). The welfare state also usually includes public provision of education, health services, and housing. Such provisions are less extensive in the U.S. than in many European countries, where comprehensive health coverage and state-subsidized university-level education have been common. In countries with centrally planned economies, the welfare state also covers employment and administration of consumer prices. Most nations have instituted at least some of the measures associated with the welfare state; Britain adopted comprehensive social insurance in 1948, and in the U.S., social-legislation programs such as the New Deal and the Fair Deal were based on welfare-state principles. Scandinavian countries provide state aid for the individual in almost all phases of life.

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Branch of economics established in the 20th century that seeks to evaluate economic policies in terms of their effects on the community's well-being. Early theorists defined welfare as the sum of the satisfactions accruing to an individual through an economic system. Believing it was possible to compare the well-being of two or more individuals, they argued that a poor person would derive more satisfaction from an increase in income than would a rich person. Later writers argued that making such comparisons with any precision was impossible. A new and more limited criterion was later developed: one economic situation was deemed superior to another if at least one person had been made better off without anyone else being made worse off. Seealso consumer's surplus; Vilfredo Pareto.

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or social welfare

Any of a variety of governmental programs that provide assistance to those in need. Programs include pensions, disability and unemployment insurance, family allowances, survivor benefits, and national health insurance. The earliest modern welfare laws were enacted in Germany in the 1880s (see social insurance), and by the 1920s and '30s most Western countries had adopted similar programs. Most industrialized countries require firms to insure workers for disability (see workers' compensation) so that they have income if they are injured, whether temporarily or permanently. For disability from illness unrelated to occupational injury, most industrial states pay a short-term benefit followed by a long-term pension. Many countries pay a family allowance to reduce the poverty of large families or to increase the birth rate. Survivor benefits, provided for widows below pension age who are left with a dependent child, vary considerably among nations and generally cease if the woman remarries. Among the world's wealthy countries, only the U.S. fails to provide national health insurance other than for the aged and the poor (see Medicare and Medicaid).

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Any government program designed to encourage the industrial and economic development of regions beset by joblessness or other economic hardship. Most industrialized countries have adopted some type of regional development program since World War II. The most common method of encouraging development is to offer grants, loans, and loan guarantees to companies relocating or expanding in the region. France, for example, has offered subsidies related to the amount of investment and the number of new jobs created, as well as loans, interest subsidies, and free land sites. Tax incentives are also used to encourage companies to invest in depressed areas. In other programs, the government may offer low-cost housing for workers and assistance in developing power, light, transportation, and sanitation facilities. Seealso development bank.

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Set of ordered instructions that enable a computer to carry out a specific task. A program is prepared by first formulating the task and then expressing it in an appropriate programming language. Programmers may work in machine language or in assembly languages. But most applications programmers use one of the high-level languages (such as BASIC or C++) or fourth-generation languages that more closely resemble human communication. Other programs then translate the instructions into machine language for the computer to use. Programs are stored on permanent media (such as a hard disk), and loaded into RAM to be executed by the computer's processor, which executes each instruction in the program, one at a time. Programs are often divided into applications and system programs. Applications perform tasks such as word processing, database functions, or accessing the Internet. System programs control the functioning of the computer itself; an operating system is a very large program that controls the operations of the computer, the transfer of files, and the processing of other programs.

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(1948–51) U.S.-sponsored program to provide economic aid to European countries after World War II. The idea of a European self-help plan financed by the U.S. was proposed by George Marshall in 1947 and was authorized by Congress as the European Recovery Program. It provided almost $13 billion in grants and loans to 17 countries and was a key factor in reviving their economies and stabilizing their political structures. The plan's concept was extended to less-developed countries under the Point Four Program.

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