2,177 research outputs found

    Integrative Modeling of Electrical Properties of Pacemaker Cardiac Cells

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    This work represents modeling of electrical properties of pacemaker (sinus) cardiac cells. Special attention is paid to electrical potential arising from transmembrane current of Na{+}, K{+} and Ca{2+} ions. This potential is calculated using the NaCaX model. In this respect, molar concentration of ions in the intercellular space which is calculated on the basis of the GENTEX model is essential. Combined use of two different models allows referring this approach to integrative modeling

    Disorder-Induced Critical Phenomena in Hysteresis: Numerical Scaling in Three and Higher Dimensions

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    We present numerical simulations of avalanches and critical phenomena associated with hysteresis loops, modeled using the zero-temperature random-field Ising model. We study the transition between smooth hysteresis loops and loops with a sharp jump in the magnetization, as the disorder in our model is decreased. In a large region near the critical point, we find scaling and critical phenomena, which are well described by the results of an epsilon expansion about six dimensions. We present the results of simulations in 3, 4, and 5 dimensions, with systems with up to a billion spins (1000^3).Comment: Condensed and updated version of cond-mat/9609072,``Disorder-Induced Critical Phenomena in Hysteresis: A Numerical Scaling Analysis'

    Behavioral and social risk factors for metabolically unhealthy obesity: data form a 12-year prospective study in the Russian population

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    Aim. To study the contribution of behavioral and social risk factors to the development of metabolically unhealthy obesity (MUO) according to a prospective study in the Russian population.Material and methods. From the HAPPIE project, 3197 people aged 45-69 years with a body mass index ≥30 kg/m2 were selected, who had all the necessary parameters for obesity phenotype determination. The prospective analysis included the first (2003-2005) and third screenings (2015-2017). A subsample was formed (n=1275; 276 men — 22%, 999 women — 78%). The mean follow-up period was 12,4 years. IDF criteria (2005) were taken for analysis.Results. Men with a metabolically healthy obesity (MHO) phenotype most often have a secondary and higher education, while women with MHO — vocational and secondary education. In women, secondary education was most often noted. Among persons with obesity, both men and women are more often not single, while having MUO as follows: 56,8% and 34,2%, respectively. Men and women have a low-intensity activity, regardless of the obesity phenotype. The prevalence of smoking in the present time does not differ in the MHO and MUO groups. Metabolically healthy women consume more alcohol than those with MUO. In men with sedentary lifestyle and fasting hyperglycemia, the risk of MUO over a 12-year follow-up period was significantly higher. In women, the risk of conversion from MHO to MUO is increased when blood pressure (BP) is ≥130/85 mmHg.Conclusion. In the Russian population, the risk of MUO in men increases with a level of physical activity <3 h/week and a blood glucose level ≥6,1 mmol/l; in women, only BP ≥130/85 mm Hg contributes to the development of MUO

    LIQUID NUTRIENT MEDIUM FOR SUBMERGED CULTIVATION OF TULAREMIA MICROBE

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    The paper describes an effective liquid nutrient medium, utilization of which in the process of submerged cultivation of the vaccine tularemia microbe strain allows for the production of high concentrations of viable biomass with low rates of dissociation, which is essential in manufacturing of live vaccines. Dry enzymatic hydrolysate of fibrin, by-product of anti-rabies immunoglobulin production is used as a nutrient-rich base of the new nutrient medium

    Critical Exponents of the N-vector model

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    Recently the series for two RG functions (corresponding to the anomalous dimensions of the fields phi and phi^2) of the 3D phi^4 field theory have been extended to next order (seven loops) by Murray and Nickel. We examine here the influence of these additional terms on the estimates of critical exponents of the N-vector model, using some new ideas in the context of the Borel summation techniques. The estimates have slightly changed, but remain within errors of the previous evaluation. Exponents like eta (related to the field anomalous dimension), which were poorly determined in the previous evaluation of Le Guillou--Zinn-Justin, have seen their apparent errors significantly decrease. More importantly, perhaps, summation errors are better determined. The change in exponents affects the recently determined ratios of amplitudes and we report the corresponding new values. Finally, because an error has been discovered in the last order of the published epsilon=4-d expansions (order epsilon^5), we have also reanalyzed the determination of exponents from the epsilon-expansion. The conclusion is that the general agreement between epsilon-expansion and 3D series has improved with respect to Le Guillou--Zinn-Justin.Comment: TeX Files, 27 pages +2 figures; Some values are changed; references update

    Three-loop critical exponents, amplitude functions, and amplitude ratios from variational perturbation theory

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    We use variational perturbation theory to calculate various universal amplitude ratios above and below T_c in minimally subtracted phi^4-theory with N components in three dimensions. In order to best exhibit the method as a powerful alternative to Borel resummation techniques, we consider only to two- and three-loops expressions where our results are analytic expressions. For the critical exponents, we also extend existing analytic expressions for two loops to three loops.Comment: Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of paper (including all PS fonts) at http://www.physik.fu-berlin.de/~kleinert/kleiner_re318/preprint.htm

    Thermodynamic characteristics of the classical n-vector magnetic model in three dimensions

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    The method of calculating the free energy and thermodynamic characteristics of the classical n-vector three-dimensional (3D) magnetic model at the microscopic level without any adjustable parameters is proposed. Mathematical description is perfomed using the collective variables (CV) method in the framework of the ρ4\rho^4 model approximation. The exponentially decreasing function of the distance between the particles situated at the N sites of a simple cubic lattice is used as the interaction potential. Explicit and rigorous analytical expressions for entropy,internal energy, specific heat near the phase transition point as functions of the temperature are obtained. The dependence of the amplitudes of the thermodynamic characteristics of the system for T>TcT>T_c and T<TcT<T_c on the microscopic parameters of the interaction potential are studied for the cases n=1,2,3n=1,2,3 and nn\to\infty. The obtained results provide the basis for accurate analysis of the critical behaviour in three dimensions including the nonuniversal characteristics of the system.Comment: 25 pages, 5 figure

    Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

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    A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

    Search for anomalous t t-bar production in the highly-boosted all-hadronic final state

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    A search is presented for a massive particle, generically referred to as a Z', decaying into a t t-bar pair. The search focuses on Z' resonances that are sufficiently massive to produce highly Lorentz-boosted top quarks, which yield collimated decay products that are partially or fully merged into single jets. The analysis uses new methods to analyze jet substructure, providing suppression of the non-top multijet backgrounds. The analysis is based on a data sample of proton-proton collisions at a center-of-mass energy of 7 TeV, corresponding to an integrated luminosity of 5 inverse femtobarns. Upper limits in the range of 1 pb are set on the product of the production cross section and branching fraction for a topcolor Z' modeled for several widths, as well as for a Randall--Sundrum Kaluza--Klein gluon. In addition, the results constrain any enhancement in t t-bar production beyond expectations of the standard model for t t-bar invariant masses larger than 1 TeV.Comment: Submitted to the Journal of High Energy Physics; this version includes a minor typo correction that will be submitted as an erratu

    Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV

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    The t t-bar production cross section (sigma[t t-bar]) is measured in proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS experiment, corresponding to an integrated luminosity of 2.3 inverse femtobarns. The measurement is performed in events with two leptons (electrons or muons) in the final state, at least two jets identified as jets originating from b quarks, and the presence of an imbalance in transverse momentum. The measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/- 2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction of the standard model.Comment: Replaced with published version. Included journal reference and DO
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