[Demographic Aspects of Population Aging in Saint-Petersburg at the End of XX-the beginning of XXI Century. Part II. Prospective Aging Measures.]

The paper is the second part of the series of two articles on demographic aspects of population aging in Saint-Petersburg in 1990-2010/2014 compared to the situation in the Russian Federation as a whole. In the first part, the situation with population aging in Saint-Petersburg and Russia was considered based on traditional aging measures. In the second part, a number of prospective aging measures that take account of remaining life expectancy are studied, such as Prop. RLE 15 (proportion of population with remaining life expectancy 15 years or less), POADR (prospective old-age dependency ratio), population average remaining years of life (PARIL). Prospective aging indicators are compared with their traditional analogues. Gender imbalance of prospective aging measures has been considered.

Plasticity of social behavior in Drosophila.

This article presents results obtained from studies of the plasticity of changes in social behavior in Drosophila (interactions between individuals in groups) in conditions of homo- and heterogeneous environments. This is the first report of data illustrating self-starting acquisition by female Drosophila of a classical conditioned reflex to contextual factors signaling possible threats from other individuals and blocking the initiation of activity. A previously described operant conditioned reflex also helped flies avoid aggression from other individuals and make more efficient use of food resources by decreasing the initially high level of activity. Classical conditioning had the effect that the fly did not need to repeat acquisition of the conditioned reflex each time: when placed into an analogous situation, the fly's activity automatically decreased as a result of exposure to the conditioned stimulus, i.e., contextual factors.

[Plasticity of the social behavior in Drosophila]. / Plastichnost' sotsial'nogo povedeniia u drozofily.

Original data illustrate self-starting classical conditioning to environmental factors in Drosophila, the factors serving as signals of a possible threat from other individuals and blocking initiation of activity. Instrumental conditioning resulting in reduction of an initially high level of activity in the group situation, helps a fly to avoid aggression from other flies and to use the food resources more efficiently. Classical conditioning makes it unnecessary for a fly to learn this instrumental task again and again: being faced with an analogous situation the fly automatically decreases its activity following presentation of the conditioned stimuli or the specific environment.