Гомеостатические реакции растений на современные изменения климата: пространственно-фенологические аспекты
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).
Many environmental stimuli present a quasi-rhythmic structure at different timescales that the brain needs to decompose and integrate. Cortical oscillations have been proposed as instruments of sensory de-multiplexing, i.e., the parallel processing of different frequency streams in sensory signals. Yet their causal role in such a process has never been demonstrated. Here, we used a neural microcircuit model to address whether coupled theta–gamma oscillations, as observed in human auditory cortex, could underpin the multiscale sensory analysis of speech. We show that, in continuous speech, theta oscillations can flexibly track the syllabic rhythm and temporally organize the phoneme-level response of gamma neurons into a code that enables syllable identification. The tracking of slow speech fluctuations by theta oscillations, and its coupling to gamma-spiking activity both appeared as critical features for accurate speech encoding. These results demonstrate that cortical oscillations can be a key instrument of speech de-multiplexing, parsing, and encoding.
The article focuses on the influence of global climate change on the world economy. The author points out that this influence is broader than damage from the transformation of environment caused by climate change and involves the variety of issues including impacts on the technological progress and formation of new carbon markets. Special attention is paid to the role of intergovernmental regulation and the composition of climate policy which change as the influence of climate change grows. Climate policy passes to the national level and switches to the priority of adaptation measures.
The given study is devoted to the issues of searching the ways for adaptation to climate change, mitigation of its impact on the economy and population, as well as to the role of increasing energy efficiency in the economies of some countries of Eastern Europe, Caucasus and Central Asia (EECCA). It also relates to the issues of responding to negative trends and emerging challenges caused by climate change. The Report represents several case studies on the above topics implemented in Moldova, Tadjikistan, Kazakhstan, Azerbaijan and the Russian Federation by the network of regional enviuronmental centres. It also contains consideration of possible methodological approaches and recommendations on addressing the above issues in the EECCA region.
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.
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.
Hypoxia of trophoblast cells is an important regulator of normal development of the placenta. However, some pathological states associated with hypoxia, e.g. preeclampsia, impair the functions of placental cells. Oxyquinoline derivative inhibits HIF-prolyl hydroxylase by stabilizing HIF-1 transcription complex, thus modeling cell response to hypoxia. In human choriocarcinoma cells BeWo b30 (trophoblast model), oxyquinoline increased the expression of a core hypoxia response genes along with up-regulation of NOS3, PDK1, and BNIP3 genes and down-regulation of the PPARGC1B gene. These changes in the expression profile attest to activation of the metabolic cell reprogramming mechanisms aimed at reducing oxygen consumption by enabling the switch from aerobic to anaerobic glucose metabolism and the respective decrease in number of mitochondria. The possibility of practical use of the therapeutic properties of oxyquinoline derivatives is discussed.