1,216 research outputs found

    Splenium of corpus callosum: patterns of interhemispheric interaction in children and adults.

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    The splenium of the corpus callosum connects the posterior cortices with fibers varying in size from thin late-myelinating axons in the anterior part, predominantly connecting parietal and temporal areas, to thick early-myelinating fibers in the posterior part, linking primary and secondary visual areas. In the adult human brain, the function of the splenium in a given area is defined by the specialization of the area and implemented via excitation and/or suppression of the contralateral homotopic and heterotopic areas at the same or different level of visual hierarchy. These mechanisms are facilitated by interhemispheric synchronization of oscillatory activity, also supported by the splenium. In postnatal ontogenesis, structural MRI reveals a protracted formation of the splenium during the first two decades of human life. In doing so, the slow myelination of the splenium correlates with the formation of interhemispheric excitatory influences in the extrastriate areas and the EEG synchronization, while the gradual increase of inhibitory effects in the striate cortex is linked to the local inhibitory circuitry. Reshaping interactions between interhemispherically distributed networks under various perceptual contexts allows sparsification of responses to superfluous information from the visual environment, leading to a reduction of metabolic and structural redundancy in a child's brain

    High and Low: The Material Culture of the Russian Diaspora in Shanghai, 1920s–1950s

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    This paper examines the material culture and consumer practices of the Russian diaspora in Shanghai in the first half of the twentieth century. The article argues that the dynamic of political estrangement and mercantile license in the international treaty port engendered consumer behavior and an economy of services uncharacteristic of Russians living in the Soviet Union. It will also suggest that the diverse enterprises and commercial street life of stateless Russian emigrants have led to permanent transformations in the urban fabric of the treaty port. By drawing on previously unexamined source material, this study addresses a problem in related scholarship that has neglected the material component of the diaspora’s experience. Through the testimony of the emigrants themselves, this paper looks at how a lengthy exile in the free-trade environment facilitated the commercial deployment of service skills, and how Russian refugee enterprises produced lasting effects on the cultural life of the city. The study provides a framework for further research demonstrating how the diaspora became the conduit of European material sensibility and global modernity for local and foreign populations

    Surface layer evolution under the external heating

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    Generalized equation system is written to describe the surface layer evolution under electron beam action. Chemical reactions and porosity evolution are taken into account. The model was used to describe the electron beam treatment of thin layer with varied thickness. The review is made for some previous particular models of electron beam surface treatment with chemical reactions and shrinkage. It was pointed that the model permits the existence of self-sustaining regimes and quasi-stationary technology regimes

    The Riddle of a Human Being: A Human Singularity of Co-evolutionary Processes

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    The theory of self-organization of complex systems studies laws of sustainable co-evolutionary development of structures having different speeds of development as well as laws of assembling of a complex evolutionary whole from parts when some elements of ldquo;memoryrdquo; (the biological memory, i.e. DNA, the memory of culture, i.e. the cultural and historical traditions, etc.) must be included. The theory reveals general rules of nonlinear synthesis of complex evolutionary structures. The most important and paradoxical consequences of the holistic view, including an approach to solving the riddle of human personality, are as follows: 1) the explanation why and under what conditions a part (a human) can be more complex than a whole (society); 2) in order to reconstruct society it is necessary to change an individual but not by cutting off the supposed undesirable past, since a human being as a microcosm is the synthesis of all previous stages of evolution, and as a result of repression of, it would seem, the wild past one can extinguish a ldquo;divine sparkrdquo; in his soul; 3) in the physical sense, singularity denotes a moment of instability, phase transition; one can talk about the human singularity of co-evolutionary processes, since in such a moment of instability individual actions of a human can play a key role in determining a channel of further development as well as in appearance of a new pattern of collective behavior in society; 4) as the models of nonlinear dynamics, elaborated at the Keldysh Institute of Applied Mathematics of the Russian Academy of Sciences in Moscow, show, there is a possibility of a direct influence of the future and even a touch of an infinitely remote future in certain evolutionary regimes and under rigorously definite conditions, more over, it turns out that such a possibility exists only for a human (admittedly, through a specific state of being inherent to him ndash; the sleep without dreams) but not for the human society

    Pressure diffusion and chemical viscosity in the filtration models with state equation in differential form

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    Some options of coupling filtration models are suggested using irreversible state equations in differential form. State equations include explicitly the coefficient of compressibility, coefficients of concentration expansion and other physical properties affecting rheological properties and composition. To construct the models, the improvement of thermodynamic relations is used. New physical factors are introduced with the help of new thermodynamic variables. The chemical viscosity, pressure diffusion and concentration expansion phenomena are taken into account. The simplest particular problems illustrating the role of new effects are distinguished for stationary filtration regime. The revealed nonlinear effects can be important when considering biology liquid flows in porous biomaterials where deviations from classical laws are possible
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