1,355 research outputs found

    Euclidean asymptotic expansions of Green functions of quantum fields (II) Combinatorics of the asymptotic operation

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    The results of part I (hep-ph/9612284) are used to obtain full asymptotic expansions of Feynman diagrams renormalized within the MS-scheme in the regimes when some of the masses and external momenta are large with respect to the others. The large momenta are Euclidean, and the expanded diagrams are regarded as distributions with respect to them. The small masses may be equal to zero. The asymptotic operation for integrals is defined and a simple combinatorial techniques is developed to study its exponentiation. The asymptotic operation is used to obtain the corresponding expansions of arbitrary Green functions. Such expansions generalize and improve upon the well-known short-distance operator-product expansions, the decoupling theorem etc.; e.g. the low-energy effective Lagrangians are obtained to all orders of the inverse heavy mass. The obtained expansions possess the property of perfect factorization of large and small parameters, which is essential for meaningful applications to phenomenology. As an auxiliary tool, the inversion of the R-operation is constructed. The results are valid for arbitrary QFT models.Comment: one .sty + one .tex (LaTeX 2.09) + one .ps (GSview) = 46 pp. Many fewer misprints than the journal versio

    Absorption in Ultra-Peripheral Nucleus-Atom Collisions in Crystal

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    The Glauber theory description of particle- and nucleus-crystal Coulomb interactions at high-energy is developed. The allowance for the lattice thermal vibrations is shown to produce strong absorption effect which is of prime importance for quantitative understanding of the coherent Coulomb excitation of ultra-relativistic particles and nuclei passing through the crystal.Comment: 8 pages, LaTe

    Landau equations and asymptotic operation

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    The pinched/non-pinched classification of intersections of causal singularities of propagators in Minkowski space is reconsidered in the context of the theory of asymptotic operation as a first step towards extension of the latter to non-Euclidean asymptotic regimes. A highly visual distribution-theoretic technique of singular wave fronts is tailored to the needs of the theory of Feynman diagrams. Besides a simple derivation of the usual Landau equations in the case of the conventional singularities, the technique naturally extends to other types of singularities e.g. due to linear denominators in non-covariant gauges etc. As another application, the results of Euclidean asymptotic operation are extended to a class of quasi-Euclidean asymptotic regimes in Minkowski space.Comment: 15p PS (GSview), IJMP-A (accepted

    ПРОФЕССОРУ ВЯЧЕСЛАВУ АЛЕКСЕЕВИЧУ ЛУДИЛОВУ - 75 ЛЕТ!

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    On the 12th October of 2012 Vyacheslav Alekseevich Ludilov is celebrating his 75-th Birthday and 55 years of his scientific and pedagogical activity. Professor Ludilov is one of the well-known scientists in field of breeding and vegetable growing. He is Honoured Science Worker of Russian Federation. V.A. Ludilov is head of the Department of seed studies and production of the All-Russian Research Institute of Vegetable Growing of RAAS.12 октября 2012 года исполнилось 75 лет со дня рождения и 55 лет трудовой, научной и педагогической деятельности известному ученому в области селекции, семеноводства и технологии выращивания овощных культур, доктору с.-х. наук, профессору, заслуженному деятелю науки РФ, заведующему отделом семеноводства и семеноведения ГНУ ВНИИО Россельхозакадемии Вячеславу Алексеевичу Лудилову

    Two-loop corrections to the correlator of tensor currents in gluodynamics

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    Results of evaluating the leading order αs\alpha_s corrections to the correlator of tensor currents in pure gluodynamics are presented. These corrections to the parton result for the correlator are not large numerically that allows one to use perturbation theory for the analysis of the resonance spectrum within the sum rules method.Comment: 10 pages, latex, no figure

    Changes in the immunological reactivity in patients with coxarthrosis and the factors that determine them

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    Background. The participation of immune responses in the pathogenesis of degenerative-dystrophic diseases of the synovial joints determines the feasibility of using more rational approaches to assessing the immune status of patients with this pathology. Despite the ongoing immunological studies in patients with degenerative-dystrophic diseases of the hip joint, there are questions related to the functioning of the immune system as a whole, which require additional research.The aim of the study was to establish the features of the relationship between the indicators of the immune status and to identify the factors that determine the nature and severity of immunological disorders in patients with coxarthrosis.Material and methods. The study is based on the results of immunological parameters in 73 patients (mean age – 45.3 ± 2.56 years) with stage III dysplastic coxarthrosis. The data obtained using cluster analysis made it possible to distribute patients into two groups. The first clinical group included 46 patients, the second one – 27 patients. The control group consisted of 28 clinically healthy individuals. Mathematical processing of the results was carried out using the Statistica 6.0 software package (StatSoft Inc., USA) and the mathematical package Mathcad 2001 Pro (MathSoft Inc., USA).Results. The levels of CD4+ and CD8+ cells and IgA were determined as the classification features that make the greatest contribution to the division of the studied groups. Model experiments have shown that a specific combination of the magnitude of each of the noted factors with a certain degree of probability makes it possible to assess the state of the initial immunological reactivity and verify the nature and severity of immunological disorders.Conclusion. The information obtained is of great importance, since it allows predicting the course of the recovery period after surgery and assessing the risk of developing possible postoperative complications in patients with severe articular pathology

    Relationship of Immune Status Indicators and Hormonal Profile in Patients with Coxarthrosis

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    Background. The dynamic balance between the immune and neuroendocrine systems and their mutual regulation provide the formation of protective reactions of the body in conditions of pathology and various stress-inducing effects. The aim of the research was to establish the nature of the relationship between the indicators of the immune status and hormonal profile in patients with coxarthrosis before and after hip replacement.Material and methods. The study involved 73 patients with stage HI dysplastic coxarthrosis, who, using cluster analysis according to immunological parameters, were divided into two groups. The first clinical group included 46 patients, the second - 27 patients. The control group consisted of 28 clinically healthy individuals.Results. In the preoperative period, correlations between indicators of the immune status and hormonal profile were different in patients of the 1st and 2nd groups and depended on the level of hormones. Moreover, in patients of the 1st group, the hormones of the stress-limiting system made the greatest contribution to this dependence, and in patients of the 2nd group - peripheral thyroid hormones. After endoprosthetics, the correlation dependence in patients of the 1st group differed from the initial one in a number of indicators of the immune status and hormonal profile, which reflects the coordinated work of these body systems under the influence of stress factors. In patients of the 2nd group, the spectrum of these indicators was limited, which indicates the failure ofmechanisms, in particular, limiting the intensity ofinflammatory reactions after surgery.Conclusion. The relationship of the studied parameters in patients of the 1st group indicates the adaptive nature of the immune and endocrine reactions in response to surgery. In patients of the 2nd group, they reflect disadaptive rearrangement, which leads to an increased risk of postoperative complications

    АНАЛИЗ РЕЗУЛЬТАТОВ ОЦЕНКИ СРЕД КАК ФОНОВ ДЛЯ ОТБОРА НА НИЗКИЙ УРОВЕНЬ НАКОПЛЕНИЯ РАДИОНУКЛИДОВ КАПУСТОЙ КИТАЙСКОЙ И ПЕКИНСКОЙ

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    The study is aimed to examine the environmental conditions and backgrounds in Russian Federationand Republicof Belarusfor utilization for breeding of Chinese cabbage and Pack Choi for resistance to accumulation of the radionuclides 137Cs and 90Sr.Работа посвящена изучению и оценке сред в Российской Федерации и Республике Беларусь для использования в селекции капусты китайской и пекинской на устойчивость к накоплению радионуклидов 137Cs и 90Sr

    O(αs)O(\alpha_s) corrections to the correlator of finite mass baryon currents

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    We present analytical next-to-leading order results for the correlator of baryonic currents at the three loop level with one finite mass quark. We obtain the massless and the HQET limit of the correlator from the general formula as particular cases. We also give explicit expressions for the moments of the spectral density.Comment: 12 pages, 2 Postscript figure

    Comparative evaluation of biochemical parameters and mineral composition of Cucurbita ficifolia, C. maxima and C. moschata fruit, grown in the northern hemisphere

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    Fruit peel/pulp distribution of biologically active compounds is an important characteristic of plant physiology and the basis of zero waste production in agriculture. Among C. ficifolia, C. maxima and C. moschata the former showed the lowest dry matter content, especially in peel, similar peel and pulp values of antioxidant activity (AOA) and polyphenol content (TP), with the highest levels in fruit placenta. Peel carbohydrate profile of C. ficifolia fruit was characterized by lower levels of disaccharides compared to C. maxima and C. moschata peel and an opposite pattern of monosaccharides accumulation. The analysis of 25 elements content in Cucurbita peel and pulp, using ICP-MS, indicated that C. ficifolia fruit are characterized by significantly high concentrations of Sr, Si and I in pulp compared to the values of C. maxima and C. moschata. On the contrary, C. maxima and C. moschata were characterized by low concentration of pulp Mn. Highly significant positive correlations were recorded between Cr-Sr, Cr-Ca and CaSr (r=0.906; 0.939 and 0.974 respectively) and P-Cu (r=0.968). Despite C. ficifolia, does not contain carotenoids, it is highly valuable due to the high levels of Si, I, Cr and Ca in peel and pulp, which reveals new areas of its application
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