460 research outputs found

    On spin-rotation contribution to nuclear spin conversion in C_{3v}-symmetry molecules. Application to CH_3F

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    The symmetrized contribution of E-type spin-rotation interaction to conversion between spin modifications of E- and A_1-types in molecules with C_{3v}-symmetry is considered. Using the high-J descending of collisional broadening for accidental rotational resonances between these spin modifications, it was possible to co-ordinate the theoretical description of the conversion with (updated) experimental data for two carbon-substituted isotopes of fluoromethane. As a result, both E-type spin-rotation constants are obtained. They are roughly one and a half times more than the corresponding constants for (deutero)methane.Comment: 13 pages with single-spacing, REVTeX, no figures, accepted for publication in <J. Phys. B

    CODATA and global challenges in data-driven science

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    This synthesis report presents the scientific results of the international conference "Global Challenges and Data-Driven Science" which took place in St. Petersburg, Russian Federation from 8 October to 13 October 2017. This event facilitated multidisciplinary scientific dialogue between leading scientists, data managers and experts, as well as Big Data researchers of various fields of knowledge. The St. Petersburg conference covered a wide range of topics related to data science. It featured discussions covering the collection and processing of large amounts of data, the implementation of system analysis methods into data science, machine learning, data mining, pattern recognition, decision-making robotics and algorithms of artificial intelligence. The conference was an outstanding event in the field of scientific diplomacy and brought together more than 150 participants from 35 countries. It's success ensured the effective data science dialog between nations and continents and established a new platform for future collaboration

    Prospects for the use of a <i>Bacillus subtilis</i> metabolites-based feed additive in dairy farming

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    Laboratory and field experiment on use of the feed additive based on Bacillus subtilis endo- and exometabolites for the cows in different physiological periods are described in the paper. The feed additive impact on main body systems of the tested cows (n = 30), milk production parameters, growth rate of the calves (n = 18) born to the said cows were examined. The feed additive was added to the diets for the cows of test groups, 15 g per cow. The feed additive was found to have a positive effect on immunohematological and metabolic processes in postpartum cows. Neutrophils’ phagocytic activity increased by 12.5% and 14.6% in the animals of test group 1 and test group 2, respectively, as compared to that one in control animals (42.8 ± 1.9%). Neutrophil absorbency increased by 2.5 times, 3.2 times and 2.1 times in the animals of test group 1, test group 2 and control group, respectively. The proportion of T-lymphocytes in blood of animals in test group 1 and test group 2 was 44.5 and 48.9%, respectively, proportion of T-lymphocytes in blood of control animals equaled to 37.5%. Trend for increase in total protein concentration in cow sera owing to increase in albumin fraction was observed in postpartum period: it was 72.91 ± 3.45 g/l in test group 1; 75.54 ± 4.12 g/l in test group 2; 70.95 ± 4.25 g/l in control group. Average daily milk yield in cows of test group 1, test group 2 and control group for the 150 days of lactation was 24.50 ± 1.86 kg; 25.33 ± 1.45 kg and 22.75 ± 4.41 kg, respectively. Higher growth rate was reported for the calves born to the cows received the diet supplemented with the said feed additive. Heifers of test group 1 and test group 2 have reached body weight of 193.51 ± 5.76 and 195.33 ± 3.76 kg and in control group – of 187.33 ± 4.98 kg within 6 months. Feed additive based on endo- and exometabolites of Bacillus subtilis is recommended for cow diets for highly productive dairy herd creation and food-producing animal welfare maintenance

    A study of the proton spectra following the capture of KK^- in 6^6Li and 12^{12}C with FINUDA

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    Momenta spectra of protons emitted following the capture of KK^- in 6^6Li and 12^{12}C have been measured with 1% resolution. The 12^{12}C spectrum is smooth whereas for 6^6Li a well defined peak appears at about 500 MeV/cc. The first observation of a structure in this region was identified as a strange tribaryon or, possibly, a Kˉ\bar K-nuclear state. The peak is correlated with a π\pi^- coming from Σ\Sigma^- decay in flight, selected by setting momenta larger than 275 MeV/cc. The Σ\Sigma^- could be produced, together with a 500 MeV/cc proton, by the capture of a KK^- in a deuteron-cluster substructure of the 6^6Li nucleus. The capture rate for such a reaction is (1.62\pm 0.23_{stat} ^{+0.71}_{-0.44}(sys))%/K^-_{stop}, in agreement with the existing observations on 4^4He targets and with the hypothesis that the 6^6Li nucleus can be interpreted as a (d+α)(d+\alpha) cluster.Comment: 21 pages, 10 figures. Accepted for publication in NP

    Production of Λ6^{6}_{\Lambda}H and Λ7^{7}_{\Lambda}H with the (Kstop^{-}_{stop},π+\pi^+) reaction

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    The production of neutron rich Λ\Lambda-hypernuclei via the (KstopK^-_stop,π+\pi^+) reaction has been studied using data collected with the FINUDA spectrometer at the DAΦ\PhiNE ϕ\phi-factory (LNF). The analysis of the inclusive π+\pi^+ momentum spectra is presented and an upper limit for the production of Λ6^6_\LambdaH and Λ7^7_\LambdaH from 6^6Li and 7^7Li, is assessed for the first time.Comment: 11 pages, 3 figures. Accepted for publication in PL

    The OPERA experiment Target Tracker

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    The main task of the Target Tracker detector of the long baseline neutrino oscillation OPERA experiment is to locate in which of the target elementary constituents, the lead/emulsion bricks, the neutrino interactions have occurred and also to give calorimetric information about each event. The technology used consists in walls of two planes of plastic scintillator strips, one per transverse direction. Wavelength shifting fibres collect the light signal emitted by the scintillator strips and guide it to both ends where it is read by multi-anode photomultiplier tubes. All the elements used in the construction of this detector and its main characteristics are described.Comment: 25 pages, submitted to Nuclear Instrument and Method

    Comparison of large-angle production of charged pions with incident protons on cylindrical long and short targets

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    The HARP collaboration has presented measurements of the double-differential pi+/pi- production cross-section in the range of momentum 100 MeV/c <= p 800 MeV/c and angle 0.35 rad <= theta <= 2.15 rad with proton beams hitting thin nuclear targets. In many applications the extrapolation to long targets is necessary. In this paper the analysis of data taken with long (one interaction length) solid cylindrical targets made of carbon, tantalum and lead is presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN PS. The secondary pions were produced by beams of protons with momenta 5 GeV/c, 8 GeV/c and 12 GeV/c. The tracking and identification of the produced particles were performed using a small-radius cylindrical time projection chamber (TPC) placed inside a solenoidal magnet. Incident protons were identified by an elaborate system of beam detectors. Results are obtained for the double-differential yields per target nucleon d2 sigma / dp dtheta. The measurements are compared with predictions of the MARS and GEANT4 Monte Carlo simulations.Comment: 43 pages, 20 figure
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