153 research outputs found

    A Quasi-Classical Model for VT and VV Rate Constants

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    Projet M3NWe present in this report vibrational rate constants for VT and VV process in a pure diatomic gas, based on the quasi-classical theory. Different approximations are derived for moderate temperatures flows. Numerical results are proposed for diatomic nitrogen (N2N_2), and compared with Adamovich et als and Billing-Fisher models

    Weighted norm inequalities for Fourier transforms of radial functions

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    "Vegeu el resum a l'inici del document del fitxer adjunt"

    Non-minimally Coupled Cosmological Models with the Higgs-like Potentials and Negative Cosmological Constant

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    We study dynamics of non-minimally coupled scalar field cosmological models with Higgs-like potentials and a negative cosmological constant. In these models the inflationary stage of the Universe evolution changes into a quasi-cyclic stage of the Universe evolution with oscillation behaviour of the Hubble parameter from positive to negative values. Depending on the initial conditions the Hubble parameter can perform either one or several cycles before to become negative forever.Comment: 22 pages, 6 figures, v4:Section 2 expanded, references added, accepted for publication in Class. Quant. Gra

    Measurement of the Pion Form Factor in the Energy Range 1.04-1.38 GeV with the CMD-2 Detector

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    The cross section for the process e+eπ+πe^+e^-\to\pi^+\pi^- is measured in the c.m. energy range 1.04-1.38 GeV from 995 000 selected collinear events including 860000 e+ee^+e^- events, 82000 μ+μ\mu^+\mu^- events, and 33000 π+π\pi^+\pi^- events. The systematic and statistical errors of measuring the pion form factor are equal to 1.2-4.2 and 5-13%, respectively.Comment: 5 pages, 2 figure

    ВНУТРИГОСПИТАЛЬНАЯ ТРАНСПОРТИРОВКА ПАЦИЕНТОВ С РАЗРЫВОМ АРТЕРИАЛЬНЫХ АНЕВРИЗМ ГОЛОВНОГО МОЗГА

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    Goal: to evaluate cerebral hemodynamics in the patients with aneurysm rupture during their transportation within the hospital. Materials and methods. 60 patients divided into 2 groups were included into the study. Patients from group 1 were transported as it was traditionally adopted in the clinic; additional sedation and continuous administration of nimodipine were used in group 2. Results. The increase of medium blood velocity in cerebral vessels by 23.5% on the operated side was observed in group 1. Continuous administration nimodipine solution during all transport stages allows reducing the velocity increase in cerebral vessels on the operated side down to 4.5%. Conclusion. The increase of cerebral angiospasm was observed during intrahospital transportation. The need for additional sedation has been justified for the patients transported while being on the artificial pulmonary ventilation. Цель: оценить церебральную гемодинамику у пациентов с разрывом аневризм при внутрибольничной транспортировке. Материалы и методы. Проведено исследование у 60 пациентов, разделенных на две группы. Больные 1-й группы транспортированы по принятой в клинике методике, а 2-й − с применением дополнительной седации и непрерывным введением нимодипина. Результаты. Отмечено нарастание средних скоростей по церебральным сосудам на 23,5% на стороне оперативного вмешательства в 1-й группе. Применение непрерывного введения раствора нимодипина на всех этапах транспортировки позволяет снизить повышение скорости по церебральным сосудам на стороне хирургического вмешательства до 4,5%. Заключение. Выявлено повышение показателей церебрального ангиоспазма при внутригоспитальной транспортировке. Обоснована необходимость применения дополнительной седации у пациентов, транспортируемых с применением искусственной вентиляции легких.

    Measurement of the solar neutrino capture rate with gallium metal

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    The solar neutrino capture rate measured by the Russian-American Gallium Experiment (SAGE) on metallic gallium during the period January 1990 through December 1997 is 67.2 (+7.2-7.0) (+3.5-3.0) SNU, where the uncertainties are statistical and systematic, respectively. This represents only about half of the predicted Standard Solar Model rate of 129 SNU. All the experimental procedures, including extraction of germanium from gallium, counting of 71Ge, and data analysis are discussed in detail.Comment: 34 pages including 14 figures, Revtex, slightly shortene

    Results from the Baksan Experiment on Sterile Transitions (BEST)

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    The Baksan Experiment on Sterile Transitions (BEST) was designed to investigate the deficit of electron neutrinos, νe\nu_{e}, observed in previous gallium-based radiochemical measurements with high-intensity neutrino sources, commonly referred to as the \textit{gallium anomaly}, which could be interpreted as evidence for oscillations between νe\nu_e and sterile neutrino (νs\nu_s) states. A 3.414-MCi \nuc{51}{Cr} νe\nu_e source was placed at the center of two nested Ga volumes and measurements were made of the production of \nuc{71}{Ge} through the charged current reaction, \nuc{71}{Ga}(νe\nu_e,e^-)\nuc{71}{Ge}, at two average distances. The measured production rates for the inner and the outer targets respectively are (54.9^{+2.5}_{-2.4}(\mbox{stat})\pm1.4 (\mbox{syst})) and (55.6^{+2.7}_{-2.6}(\mbox{stat})\pm1.4 (\mbox{syst})) atoms of \nuc{71}{Ge}/d. The ratio (RR) of the measured rate of \nuc{71}{Ge} production at each distance to the expected rate from the known cross section and experimental efficiencies are Rin=0.79±0.05R_{in}=0.79\pm0.05 and Rout=0.77±0.05R_{out}= 0.77\pm0.05. The ratio of the outer to the inner result is 0.97±\pm0.07, which is consistent with unity within uncertainty. The rates at each distance were found to be similar, but 20-24\% lower than expected, thus reaffirming the anomaly. These results are consistent with νeνs\nu_e \rightarrow \nu_s oscillations with a relatively large Δm2\Delta m^2 (>>0.5 eV2^2) and mixing sin22θ^2 2\theta (\approx0.4).Comment: Paper updated to final versio
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