[Biological age as an index of human health level, aging and ecological well-being].

Methodology of estimating the integral health and aging level is based on the system index of biological age (BA). The paper introduces the reader to the BA principles and structure, search for meaningful aging biomarkers, useful tests, and applications in present-day biomedicine. The concept of BA is directly linked with the theory of organism vitality.

[The system theory of aging: methodological principles, basic tenets and applications].

The paper deals with the system theory of aging constructed on the basis of present-day scientific methodology--the system approach. The fundamental cause for aging is discrete existence of individual life forms, i.e.

[A system of simulation models of the epidemic process based on a socioecological concept].

In this paper different methods of modeling the epidemic process for different types of infectious diseases are discussed. We propose a concept of modeling for an essentially nonhomogeneous human population, taking into account biological, ecological and social factors. The method of an "epidemiological tree" has been developed, which makes it possible to divide the population into so-called "epidemiologically active groups".