98 research outputs found

    Angular and Current-Target Correlations in Deep Inelastic Scattering at HERA

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    Correlations between charged particles in deep inelastic ep scattering have been studied in the Breit frame with the ZEUS detector at HERA using an integrated luminosity of 6.4 pb-1. Short-range correlations are analysed in terms of the angular separation between current-region particles within a cone centred around the virtual photon axis. Long-range correlations between the current and target regions have also been measured. The data support predictions for the scaling behaviour of the angular correlations at high Q2 and for anti-correlations between the current and target regions over a large range in Q2 and in the Bjorken scaling variable x. Analytic QCD calculations and Monte Carlo models correctly describe the trends of the data at high Q2, but show quantitative discrepancies. The data show differences between the correlations in deep inelastic scattering and e+e- annihilation.Comment: 26 pages including 10 figures (submitted to Eur. J. Phys. C

    Plastisol Foaming Process. Decomposition of the Foaming Agent, Polymer Behavior in the Corresponding Temperature Range and Resulting Foam Properties

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    The decomposition of azodicarbonamide, used as foaming agent in PVC - plasticizer (1/1) plastisols was studied by DSC. Nineteen different plasticizers, all belonging to the ester family, two being polymeric (polyadipates), were compared. The temperature of maximum decomposition rate (in anisothermal regime at 5 K min-1 scanning rate), ranges between 434 and 452 K. The heat of decomposition ranges between 8.7 and 12.5 J g -1. Some trends of variation of these parameters appear significant and are discussed in terms of solvent (matrix) and viscosity effects on the decomposition reactions. The shear modulus at 1 Hz frequency was determined at the temperature of maximum rate of foaming agent decomposition, and differs significantly from a sample to another. The foam density was determined at ambient temperature and the volume fraction of bubbles was used as criterion to judge the efficiency of the foaming process. The results reveal the existence of an optimal shear modulus of the order of 2 kPa that corresponds roughly to plasticizer molar masses of the order of 450 ± 50 g mol-1. Heavier plasticizers, especially polymeric ones are too difficult to deform. Lighter plasticizers such as diethyl phthalate (DEP) deform too easily and presumably facilitate bubble collapse

    Association of body temperature with obesity. The CoLaus study.

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    There is conflicting evidence regarding the association between body temperature and obesity. We aimed to assess the associations between body temperature and several adiposity and metabolic markers according to gender and menopausal status in a large population-based sample. The data collected between 2009 and 2012 from 4224 participants (mean age 57.3 ± 10.4 years, 2225 women) of the CoLaus study (Lausanne, Switzerland). Body temperature was measured at the tympanic membrane. Mean body temperature was 36.1 ± 0.4, 36.4 ± 0.4 and 36.3 ± 0.4 °C in men, premenopausal, and postmenopausal women, respectively (p < 0.001). In men and postmenopausal women, body temperature was positively and significantly (p < 0.05) associated with body mass index (Spearman correlation coefficients 0.157 and 0.083, respectively), waist (r = 0.163 and r = 0.104), waist to hip ratio (r = 0.187 and r = 0.132), body area (r = 0.094 and r = 0.085), resting heart rate (r = 0.227 and r = 182), glucose (r = 0.104 and r = 0.088) and insulin (r = 0.148 and r = 0.117). Except for body area and BMI in postmenopausal women, all associations remained significant after multivariable adjustment. In premenopausal women, body temperature was positively associated with resting heart rate (r = 0.140) and insulin (r = 0.170), and no significant associations were found after multivariable adjustment. Body temperature is strongly associated with obesity markers in men and postmenopausal women. The absence of association in premenopausal women might be due to the influence of the menstrual cycle

    Angular and Current-target Correlations in Deep Inelastic Scattering at HERA

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    Correlations between charged particles in deep inelastic e+ p scattering have been studied in the Breit frame with the ZEUS detector at HERA using an integrated luminosity of 6.4pb-1. Short-range correlations are analysed in terms of the angular separation between current-region particles within a cone centred around the virtual photon axis. Long-range correlations between the current and target regions have also been measured. The data support predictions for the scaling behaviour of the angular correlations at high Q2 and for anti-correlations between the current and target regions over a large range in Q2 and in the Bjorken scaling variable x. Analytic QCD calculations and Monte Carlo models correctly describe the trends of the data at high Q2, but show quantitative discrepancies. The data show differences between the correlations in deep inelastic scattering and e+e- annihilation

    Mean-field transport theory for the two-flavour NJL model

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    By making decomposition of the Wigner function simultaneously in both the spinor and the isospin spaces we derive a set of kinetic equations for the quark distribution functions and the spin densities. A detailed analysis of the consequences imposed by the chiral invariance on the form of the transport equations is presented.Comment: Revtex, 25 pages, no figure

    Conseqüências do exercício para o metabolismo da glutamina e função imune

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    Para o atleta, o objetivo do treinamento é aperfeiçoar sua capacidade física para obtenção do melhor desempenho em competições. Isso o leva a procurar os mais novos e eficientes métodos de treinamento. Um aspecto importante do programa de treinamento é o período de recuperação entre as sessões de exercícios, imprescindível para que ocorram as adaptações fisiológicas, como as alterações morfológicas e a supercompensação das reservas energéticas. A liberação de glutamina pelos músculos esqueléticos é aumentada durante o exercício. Como conseqüência, o conteúdo muscular de glutamina diminui após um exercício extenuante. Este aminoácido, entretanto, é muito importante para a funcionalidade dos leucócitos (linfócitos, macrófagos e neutrófilos). Portanto, após um exercício intenso, a concentração plasmática de glutamina diminui, suprimindo a função imune e tornando o indivíduo mais suscetível a infecções respiratórias. Nesta revisão são discutidas as implicações do exercício sobre o metabolismo dos músculos esqueléticos e leucócitos
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