390 MODELS FOR DEVELOPMENT OF S AND T ijUMAN RESOURCES The maJor target for study of the professional structure of the scientific and sclentlflc-pedagogleal personnel Is ~he proportions of their subject and functional distribution In the system of scJentlflc activities; exploration for efficient ~lstrtbutlon In the system of scientific activities; exploration for efficient methods of maintaining these proportions, and Investigation· of the possibilities of .optimum combination of different subject and functional elements ln.the activities of scientists and scientific collectives. In the USSR there are three groups of "controlled" moa&ls, permitting the prognostication of the number of scientific personnel: model of requirements •. model of supply •nd balance model. The requirement establ !shes the relations between the number of scientific workers and the level of development of the national economy estimated as the ratio of the Increment of social labour productivity to the national Income. and prognosti­ cates the requirement In scientific personnel to ensure the expected raise In this level. The supply model constitutes a system of scientific personnel as a sum of different levels of professional­ qual lflcatlon levels and the relations between them. An enlarged model of this type takes Into account _the graduation of students from higher educational Institutions and post-graduate courses. the share of graduates Immediately starting scientific work specialists having experience of other work ~nd natural losses. etc. The aim of the balance model Is to coordinate the requirement and supply of scientific personnel. DISTRIBUTION The number of scientific and scientific-pedagogical workers and their attributes are shown In table 1. Statistical accounting of scientific workers by the branches of science Is performed In the USSR annually, and by the scientific professions from the beginning of the 60s. A substantial Increase In the number of scientific workers was observed In each branch of science during 1950-1974 as shown In table 2. 
**Analysis**
The text appears to be focused on the development of scientific and technological resources, particularly in the context of human resources and personnel management. It discusses models and methods for predicting and managing the supply and demand of scientific personnel, as well as their distribution across different branches of science and professions. The text does not seem to be related to economic development, natural resources, agriculture, forestry, fishing, industry, transport, communication, international trade, health, humanitarian aid, or culture.

**Category**
Education, Science and technology