The feasibility of ecological standardization of physicochemical factors that do not refer to concentrations of polluting substances (water regime, water temperature, and pH) is confirmed. The opportunity of standardization is provided with the approach developed by the authors, which is based on joint analysis of the data of biological and physicochemical monitoring. Additional opportunities provided by the method used for the analysis are connected with calculating the admissible influence values that vary in time. The seasonal dynamics of the obtained ecologically tolerable levels (ETL) for factors disturbing the well being of biological indicators is investigated. The water sample points are analyzed concerning their ecological well being or ill being depending on observance or nonobservance of ETL values.

A study was conducted to investigate dependence of the speed of forgetting on the volume of retained information on the material of adolescents memorizing words. Comparison of individual data with two models of forgetting (exponential dependence on root of time and restricted exponential dependence) shows that speed of forgetting does not depend on completeness of memorizing.

A brief history is recounted of the mathematical theory of life history evolution which originates from works by L. Euler, T. Malthus, A. Lotka, and R. Fisher, but has been developed in its final form in 1970s. Basic approaches to modeling life history evolutionary ecology--the explicit, optimization, and adaptive dynamics ones--are evaluated with an emphasis on their methodological advantages and shortcomings. The explicit approach deals with direct modeling of coupled changes in size of populations--which are treated as assemblages of individuals with different life history strategies--and takes into account the interactions between populations themselves and between populations and their environment. The approach is methodologically transparent, though requires a great deal of computing resources for resolving problems complex in formulation. Besides, since it deals with specific modeling situations, it is not well suited for drawing general conclusions. The optimization approach is grounded on a search for life history strategies ensuring the maximization of the given measure of evolutionary fitness--most often, lifetime reproductive success or Malthusian parameter. Owing to the possibility for applying efficient analytical or numerical methods from the mathematical theory of optimal control, it allows to reveal optimal evolutionary strategies in rather complicated situations. Still, its usage is associated with significant methodological obstacles originated from the necessity of optimization criterion substantiation. The adaptive dynamics approach addresses to methods of the qualitative theory of differential equations while investigating evolutionary changes in phenotypic traits and life history strategies in particular. Within its framework, interactions between the main population (resident) and an alien population (invader), which is very small in size, are modeled. This approach allows to explore subtle aspects of evolutionary dynamics and to formulate and analyze mathematically some major problems of the theory of evolution--for example, the problem of sympatric speciation. However, application of this approach is also restricted due to specificity of objectives formulation as well as complexity of respective mathematical tools.

Like many trophically transmitted parasites, the trematode Microphallus papillorobustus alters the behavior of its intermediate host, the crustacean gammarid Gammarus insensibilis, in a way that favors its vulnerability to definitive hosts (aquatic birds). Parasitized females still produce eggs, but because juvenile development occurs inside the female marsupial brood pouch, young gammarids are subject to the same risk of predation as their mothers until they exit the marsupium. We explored the idea that developing juveniles can adjust their developmental schedule in a state-dependent manner according to the parasitic status of the mother. We predicted that juveniles from parasitized females would accelerate their development, or exit the marsupium at an earlier stage, to avoid predation by birds. Contrary to our expectations, we observed the opposite, that is, juveniles from parasitized females exited the marsupial brood pouch significantly later than those from uninfected mothers. We discuss these results in relation to current ideas on host manipulation by parasites in ecosystems.

The paper analyzes dependence of time perception on the social and demographic status of the individuales and their personal psychological characteristics and attitudes. It has been discovered that women, compared to men, and more educated individuals remember a greater number of events. There is a relative lowering ("a reminiscence drop") of the number of recalled events relating to the period of youth. Events-from childhood and youth retained in memory are more varied in content. The ratio of retained important sad events increases with age.

The tip-of-the-tongue state, or memory blocking, is considered with regard to the feasibility of its neural network modeling. The results of psycholinguistic and neurobiological studies on memory blocking are reviewed, and basic problems that need be solved to comprehend this phenomenon are formulated. One such point is the dramatic discrepancy between the subjective assurance that an image is familiar and the inability to recollect it fully. To explain this discrepancy, we propose a biologically plausible neural network model of recognition, demonstrating cardinal superiority in the capacity of image recognition over its recollection.

The capacities of a specially designed neural network for familiarity recognition and recollection have been compared. Recognition is based on calculating “image familiarity” as a modified Hopfield energy function in which the value of the inner sum is replaced by the sign of this value. This replacement makes the calculation of familiarity compatible with the basic dynamic equations of the Hopfield network and is in fact reduced to calculating the scalar product of the neuronet state vectors at two successive time steps.

The authors discuss a model of age-related change in subjective time perception based on interrelation of memorizing and recalling autobiographical events. Factual data show that the worst to be recalled are events of approximately 13 years ago. This phenomenon provides explanation for the so-called telescopic effect of subjective perception of past events, which means that earlier events are perceived as more recent than later ones. Besides, the model explains the phenomenon of subjective acceleration of time in middle age and also allows possibility of a "collective memory failure".

The work is focused on studying the possibility to ecologically standardize the characteristics that are not concentrations of chemical substances, i.e., water abundance; water temperature; and pH, which does not belong to standardized characteristics. The initial data include the data of biological (water quality classes by characteristics of plankton, periphyton, and zoobenthos) and physicochemical monitoring in 1975–1991 in water bodies of the Lower Don, as well as data on fish catches and yield in the Lower Don. The values of ecologically tolerable levels are obtained for three factors, such that going above these levels causes the environmental ill-being of the appropriate biological indicator. Nonchemical impacts, represented by water abundance and temperature have almost no effect on the deterioration of ichthyological estimates of the state (the only exception is the correlation between water abundance and sabrefish catches). At the same time, planktonic and benthic estimates appear to be more sensitive indicators of water quality decline in all three factors under consideration. The pH exponent affects all ecological groupings of Don ecosystems. The strictest upper boundaries of ecologically tolerable levels of water abundance were recorded for the sabrefish catches. On the other hand, insufficient water abundance during spring and summer deteriorates the state of planktonic and benthic organisms.

We consider a neural network model of age-related cognitive changes in aging brain based on Hopfield network with a sigmoid function of neuron activation. Age is included in the activation function as a parameter in the form of exponential rate denominator, which makes it possible to take into account the weakening of interneuronal links really observed in the aging brain. Analysis of properties of the Lyapunov function associated with the network shows that, with increasing parameter of age, its relief becomes smoother and the number of local minima (network attractors) decreases. As a result, the network gets less frequently stuck in the nearest local minima of the Lyapunov function and reaches a global minimum corresponding to the most effective solution of the cognitive task. It is reasonable to assume that similar changes really occur in the aging brain. Phenomenologically, these changes can be manifested as emergence in aged people of a cognitive quality such as wisdom i.e. ability to find optimal decisions in difficult controversial situations, to distract from secondary aspects and to see the problem as a whole.

Cognitive and regulatory processes in organism are ensured by the functioning of several different network systems - neural, endocrine, immune, and gene ones. These systems are, however, closely related and form a single integrated neurogenohumoral cognitive-regulatory dynamic system of organism. A review of publications is given which shows that it is possible to associate with this dynamic system a corresponding Lyapunov function (energy function, potential function) and that analyzing this function allows, due to its geometrical insight, to easily discover a set of general properties of cognitive and regulatory functioning of organism.