Экологические функции исторических природных территорий
Discusses the importance and function of historical Park territories in the system of biosphere processes. Their main feature is the combination of natu-ral and man-made components in a single ecological space that leads to com-plexity in examining these territories and the importance of understanding the laws of their development in the context of global and regional natural processes.
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.
Echiurida is a small group of marine benthic invertebrates that burrow in sediments and live a hidden lifestyle. Investigation of the morphology and anatomical features of various organ systems allows better understanding of the biology of these enigmatic animals, many of which are deep-sea species. The morphology and microscopic anatomy of the deep-sea echiurid Protobonellia zenkevitchi Murina, 1976 have been studied using the light microscopy and histology methods. The body of P. zenkevitchi is divided into a proboscis and trunk. The ciliary grooves and large vacuolated cells in the connective tissue of the distal part of the proboscis suggest a specific position of the proboscis on the sediment surface and a mechanism for sorting food particles. It has been shown for the first time that the coelom is not subdivided into compartments. In the digestive tract, an unusual part of the midgut has been found that was previously unknown in echiurids; it probably performs the function of food storage. This part contributes to thorough food digestion, which is important in the oligotrophic conditions of greater depths. The circulatory system of P. zenkevitchi lacks the neuro-intestinal and ring blood vessels. The oocyte storage chamber of the gonoduct has a pore, which apparently connects its cavity with the trunk coelom, but lacks a specialized and well-expressed part, the androecium. A comparative analysis of the microscopic anatomy shows that many organ systems (muscular, coelomic, circulatory, excretory, and reproductive) in P. zenkevitchi have a simpler organization compared to those in other echiurids. This can probably be explained by the small body size of P. zenkevitchi and the great depths of its habitat. At the same time, P. zenkevitchi possesses some unique anatomical characteristics related to the features of the biology of this deep-sea species.
The Phoronida, which is one of the smallest phyla of invertebrates, includes only 13 valid species, although ~40 larval forms of phoronids were recently described. This report uses light microscopy and molecular methods to describe a new phoronid species, Phoronis embryolabi Temereva & Chichvarkhin, sp. nov. The morphology of P. embryolabi, which lives commensally in the burrows of Axiidea shrimp Nihonotrypaea japonica in Vostok Bay (the Sea of Japan), is extremely similar to that of Phoronis pallida Silen, 1952; the bodies of both species exhibit specific regionalisation. However, the organisation of the metanephridia differs between P. pallida and P. embryolabi. Moreover, P. embryolabi has a unique type of development, viviparity, in which mothers release fully developed larvae into the environment. In all other phoronid species, the spawning occurs as a release of fertilised eggs or early embryos. Viviparity of completely developed larvae has not been previously described for any phoronid. According to analysis of partial 28S rRNA, P. embryolabi is close to Phoronis pallida. On the other hand, analysis of partial cytochrome c oxidase subunit I indicated a unique position of P. embryolabi among phoronids. These results should be used for revision of phoronid taxonomy (i.e. the type of development should be considered as characteristic of subgenera within the genus Phoronis). This report also establishes the relationship between P. embryolabi and an Actinotrocha sp. that was described in a previous paper.
In the first part of this article we survey general similarities and differences between biological and social macroevolution. In the second (and main) part, we consider a concrete mathematical model capable of describing important features of both biological and social macroevolution. In mathematical models of historical macrodynamics, a hyperbolic pattern of world population growth arises from non-linear, second-order positive feedback between demographic growth and technological development. Based on diverse paleontological data and an analogy with macrosociological models, we suggest that the hyperbolic character of biodiversity growth can be similarly accounted for by non-linear, second-order positive feedback between diversity growth and the complexity of community structure. We discuss how such positive feedback mechanisms can be modelled mathematically.
Contemporary state of the competitive intransitivity hypothesis is considered. Intransitive competition among species occurs when, for example, species A outcompetes species B, B outcompetes C, and C outcompetes A (sometimes written as A > B > C > A). In the first part of the article, a summary of the studies of competitive intransitivity is given. Examples of really existing intransitive loops are discussed, as well as simulation models that provide a theoretical explanation for these processes. Pro hac vice, sufficient potential diversity of community, species interactions carried out in relatively stable limited space that can be reclaimed, and a penalty for the acquisition of competitive ability are prerequisite. In the second part, the hypothesis of competitive intransitivity is compared with neutral theory and niche theory. The results are believed to make some generalizations possible which could stimulate deeper understanding of the species coexistence phenomenon.
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.