Cortisol As a Marker of Stress
The review considers the roles cortisol (Crt), dehydroepiandrosterone (DHEA), and DHEA sul fate (DHEAS) play in the stress response. Agerelated, sexrelated, and circadian fluctuations in normal conditions and in acute or chronic stress are described for Crt, DHEA, and DHEAS. The main techniques used to estimate the Crt level in the blood, urine, and saliva are described, and approaches to the interpretation of the results discussed. Special attention is paid to Crt assays in anthropological and psychological studies.
Efficient regulation of internal homeostasis and defending it against perturbations requires adaptive behavioral strategies. However, the computational principles mediating the interaction between homeostatic and associative learning processes remain undefined. Here we use a definition of primary rewards, as outcomes fulfilling physiological needs, to build a normative theory showing how learning motivated behaviors may be modulated by internal states. Within this framework, we mathematically prove that seeking rewards is equivalent to the fundamental objective of physiological stability, defining the notion of physiological rationality of behavior. We further suggest a formal basis for temporal discounting of rewards by showing that discounting motivates animals to follow the shortest path in the space of physiological variables toward the desired setpoint. We also explain how animals learn to act predictively to preclude prospective homeostatic challenges, and several other behavioral patterns. Finally, we suggest a computational role for interaction between hypothalamus and the brain reward system.
A series of dates of unfolding of the first leaves and duration of the season of vegetation in the silverbirch (Betula pendula Roth. (B. verrucosa Ehrh.)), as well as the duration of flowering of the bird cherry (PaFdus avium), mountain ash (Sorbus aucuparia), andsmall-leaved lime (Tilia cordata Mill.) for the period1970–2010 in the central part of European Russia were studied in order to assess the trends. Differences in phenological responses to homogeneous climate changes in the trees of the same species from the northernand southern parts of the range were revealed. If spring events occur 3–7 days earlierin the northern part, nosuch effect is observed in the south. This fact can be interpreted as a manifestation of the different mechanisms of homeostasis in different populations determined by their biological characteristics (in particular, by the need to pass successfully the periods of organic rest and vegetation).
The role of cortisol (Crt), dehydroepiandrosterone (DHEA) and DHEAsulfate (DHEAS) in stress responses were shown. The fluctuations in concentration of Crt, DHEA and DHEAS depending on age, sex and time of the day in norm and under acute and chronic stress were quoted. The main techniques of assessment of serum, urine and saliva Crt concentrations were discussed. A special attention had been paid to the use of Crt concentration in anthropological and psychological research. Bibliography comprises 181 works.
The results of cross-cultural research of implicit theories of innovativeness among students and teachers, representatives of three ethnocultural groups: Russians, the people of the North Caucasus (Chechens and Ingushs) and Tuvinians (N=804) are presented. Intergroup differences in implicit theories of innovativeness are revealed: the ‘individual’ theories of innovativeness prevail among Russians and among the students, the ‘social’ theories of innovativeness are more expressed among respondents from the North Caucasus, Tuva and among the teachers. Using the structural equations modeling the universal model of values impact on implicit theories of innovativeness and attitudes towards innovations is constructed. Values of the Openness to changes and individual theories of innovativeness promote the positive relation to innovations. Results of research have shown that implicit theories of innovativeness differ in different cultures, and values make different impact on the attitudes towards innovations and innovative experience in different cultures.
A joint research project carried out by an interdisciplinary group of Russian and Swedish linguists, sociologists and educators-psychologists (the Swedish Institute grant), besides solving pragmatic tasks of finding out relative quantitative-qualitative specificity of national cognitive representations of values, first of all, had methodological goals. They were to check the efficiency of the linguistic methods developed in this study (and, thus, to prove the theoretical ideas that served the basis for it) of getting factual data that allow reconstructing and comparing of the corresponding areas of cognitive representations.