[On some demographic characteristics of the members of the Russian Academy of Sciences in the 20th century].

The demographic life characteristics of the Russian science elite (full and corresponding members of the Academy of Sciences in 20th century) and the relationship between their birth and death dates are given in the paper. The following demographic characteristics of the RAS members have been estimated: a) the mean life span of full RAS members is 75 years, and of corresponding members--72.1 years; b) the mean life span of full RAS members after their election is 16.6 years, and that of corresponding members is 17 years; c) the mean age of the election to the Academy is 58.4 years for full members and 55 years for the corresponding members. These characteristics were used to analyze the social status of the group representing potential academic elite and to evaluate changes in that status caused by the fact of their election to the Academy. It has been found that the mean, maximum and minimum ages of their election to the Academy actually coincide with respective characteristics of Nobel Prize winners. However the life span of the latter after awarding is significantly, over 3 years, greater than that of full RAS members after their election. There is a small proportion of women among the members of the Academy (2%). This is also true for Nobel Prize winners (3.2%). It is shown that a week period of +/-3 days of the birth date for the members of the Academy is characterized by a much higher mortality rate exceeding the average one by about 60%. A similar tendency was shown earlier for the eminent persons of the world community in literature, science, business, and politics in 18th-20th centuries.

[A model for the formation of ring-shaped structures in colonies of mycelial fungi]. / Model' orbazovaniia kol'tsevykh struktur v koloniiakh mitselial'nykh gribov.

Mathematical model of the development of the pattern of colonies is considered. The model represents the systems of differential equations of the first order. It includes non-dimensional parameters characterizing the following features: concentration of substrate, concentration of metabolic products--growth inhibitor, mycelium and spores, radial and specific rate of mycelium growth, rate of substrate consumption and production of metabolic products, coefficients of diffusion of substrate and metabolic products, initial concentration of mycelium and substrate, time of delay of mycelium reaction on metabolic products and spore formation, threshold concentration of metabolic products. The model is adequate to the experiments with cultivation of Penicillium chrysogenum. It was shown that necessary condition for the formation of the circle periodical structures (zoning) in the colonies is an ability for the production of growth inhibitors (antibiotics, etc.). It was proved that formation of colonies of "continuous lawn" type is caused by restrictions on growth because of mycelium satiation or exhaustion of substrate. Such growth scenario is realized in experiments either on reach substrate or on hungry agar. For the appearance of regulating of "zone structure" type limitation on critical level of metabolic product concentration is very important. The number of periodical zone structures and their widths are determined by the above parameters.