1,659 research outputs found

    On the nutrition of Polyphemus pediculus (L.). [Translation from: Trudy Instituta Biologii Vnutrennykh Vodnany 12(15) 170-174, 1966.]

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    Many sides of the biology of Polyphemus pediculus are adequately studied at the present time. Most complicated is the question of its feeding. Dissection does not give an idea of the composition of the food, since Polyphemus strongly grinds its food with its mandibles. For clarification of the composition of the food of Polyphemus pediculus, the authors carried out in July and August 1962 a series of experiments with the application of radio-carbon methods in order to judge the degree of utilization of one or other foods by the quantity of C14, accumulated in the body of the crustacean after feeding. Particular attention in these experiments was given to the question of the possibility of the utilization by polyphemus of plant food - bacteria, algae and detritus

    The effectiveness of modern technologies of secondary opening of productive horizons and the ways of its improvement

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    The technologies of secondary penetration of productive formations are considered. Main factors affecting the efficiency of technologies in well completion and operation are shown

    On Dimensional Degression in AdS(d)

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    We analyze the pattern of fields in d+1 dimensional anti-de Sitter space in terms of those in d dimensional anti-de Sitter space. The procedure, which is neither dimensional reduction nor dimensional compactification, is called dimensional degression. The analysis is performed group-theoretically for all totally symmetric bosonic and fermionic representations of the anti-de Sitter algebra. The field-theoretical analysis is done for a massive scalar field in AdS(d+d^\prime) and massless spin one-half, spin one, and spin two fields in AdS(d+1). The mass spectra of the resulting towers of fields in AdS(d) are found. For the scalar field case, the obtained results extend to the shadow sector those obtained by Metsaev in [1] by a different method.Comment: 30 page

    Bulk Nanocrystalline Thermoelectrics Based on Bi-Sb-Te Solid Solution

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    A nanopowder from p-Bi-Sb-Te with particles ~ 10 nm were fabricated by the ball milling using different technological modes. Cold and hot pressing at different conditions and also SPS process were used for consolidation of the powder into a bulk nanostructure and nanocomposites. The main factors allowing slowing-down of the growth of nanograins as a result of recrystallization are the reduction of the temperature and of the duration of the pressing, the increase of the pressure, as well as addition of small value additives (like MoS2, thermally expanded graphite or fullerenes). It was reached the thermoelectric figure of merit ZT=1.22 (at 360 K) in the bulk nanostructure Bi0,4Sb1,6Te3 fabricated by SPS method. Some mechanisms of the improvement of the thermoelectric efficiency in bulk nanocrystalline semiconductors based on BixSb2-xTe3 are studied theoretically. The reduction of nanograin size can lead to improvement of the thermoelectric figure of merit. The theoretical dependence of the electric and heat conductivities and the thermoelectric power as the function of nanograins size in BixSb2-xTe3 bulk nanostructure are quite accurately correlates with the experimental data.Comment: 35 pages, 24 figures, 4 tables, 52 reference

    Theoretical simulation of the picosecond runaway-electron beam in coaxial diode filled with SF6 at atmospheric pressure

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    This paper presents detailed results of gas discharge theoretical simulation and the explanation of probabilistic mechanism of fast-electrons generation. Within the framework of a hybrid mathematical model, the hydrodynamic and the kinetic approaches are used simultaneously in order to describe the dynamics of different components of a low-temperature discharge plasma. The breakdown of a coaxial diode occurs in the form of a dense plasma region expanding from the cathode. On this background there is a formation of runaway electrons that are initiated by the ensemble of plasma electrons generated in the region of locally enhanced electric field within the front of the dense plasma. It is shown that the power spectrum of fast electrons in the discharge contains the group of electrons with the so-called “anomalous” energies. Comparison of the calculation results with the existent experimental data gives a good agreement for all major process parameters

    Off-diagonal correlations of the Calogero-Sutherland model

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    We study correlation functions of the Calogero-Sutherland model in the whole range of the interaction parameter. Using the replica method we obtain analytical expressions for the long-distance asymptotics of the one-body density matrix in addition to the previously derived asymptotics of the pair-distribution function [D.M. Gangardt and A. Kamenev, Nucl. Phys. B, 610, 578 (2001)]. The leading analytic and non-analytic terms in the short-distance expansion of the one-body density matrix are discussed. Exact numerical results for these correlation functions are obtained using Monte Carlo techniques for all distances. The momentum distribution and static structure factor are calculated. The potential and kinetic energies are obtained using the Hellmann-Feynman theorem. Perfect agreement is found between the analytical expressions and numerical data. These results allow for the description of physical regimes of the Calogero-Sutherland model. The zero temperature phase diagram is found to be of a crossover type and includes quasi-condensation, quasi-crystallization and quasi-supersolid regimes.Comment: 17 pages, 7 figure

    Generalized action principle and extrinsic geometry for N=1 superparticle

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    It is proposed the generalized action functional for N=1 superparticle in D=3,4,6 and 10 space-time dimensions. The superfield geometric approach equations describing superparticle motion in terms of extrinsic geometry of the worldline superspace are obtained on the base of the generalized action. The off-shell superdiffeomorphism invariance (in the rheonomic sense) of the superparticle generalized action is proved. It was demonstrated that the half of the fermionic and one bosonic (super)fields disappear from the generalized action in the analytical basis. Superparticle interaction with Abelian gauge theory is considered in the framework of this formulation. The geometric approach equations describing superparticle motion in Abelian background are obtained.Comment: 31 pages. Late

    Eating behavior features and preferred diets in underweight and obese young men

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    BACKGROUND: Actual nutrition and eating behavior features affect the formation of excess or underweight which in turn are risk factors for the development of chronic non-infectious diseases.AIM: To assess eating behavior features and consumption of basic nutrients in relation to metabolic disorders in underweight and obese young men of military age.MATERIALS AND METHODS: The study enrolled 86 young men aged 18 to 23 years that were referred by military enlistment office due to violations in body weight and examined in the hospital. Participants were divided into 2 groups depending on the value of the body mass index (BMI): group 1 (n=41) — underweight (Uw) young men; group 2 (n=45) — obese (Ob) young men. Anthropometric, hormonal and biochemical parameters of the body were measured; the type of eating disorder (ED) was evaluated using the Dutch DEBQ questionnaire, the presence and severity of anxiety and depressive disorders were assessed using the Hospital Anxiety and Depression Scale; assessment of the actual diet was performed using «Somatonic» computer soft.RESULTS: Absolute intake of all essential nutrients was higher in Ob young men; the relative consumption of protein and cholesterol was higher in Uw young men, whereas relative fats intake was higher in Ob group. EDs were statistically significantly more common in Ob young men. The values of all anthropometric indicators were higher in Ob group, while Uw young men predominantly demonstrated deficiency of the body fat component which did not affect key hormonal and metabolic indicators values. In Ob young men carbohydrate metabolism hormonal regulation disorders along with increased blood pressure were revealed.CONCLUSION: The ratio of proteins and fats intake should be taken into account in dietary regimens composition; Uw young men need to increase the proportion of fat and reduce protein intake, whereas Ob young men on the contrary need to reduce the proportion of fat and increase amount of proteins enhancing energy expenditure due to the specific dynamic food action
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