1,057 research outputs found

    Применение метода долгосрочного прогнозирования водонефтяного фактора для определения максимально возможного расчётного объёма добычи нефти месторождения "Чёрный Дракон", Вьетнам

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    Objective - Although junctional adhesion molecule-A (JAM-A) has recently been implicated in leukocyte recruitment on early atherosclerotic endothelium and after reperfusion injury, its role in neointima formation after arterial injury remains to be elucidated. Methods and Results - Here we show that the genetic deletion of JAM-A in apolipoprotein E - deficient (apoE(-/-)) mice significantly reduced neointimal hyperplasia after wire injury of carotid arteries without altering medial area. This was associated with a significant decrease in neointimal macrophage content, whereas the relative content of smooth muscle cells and endothelial recovery was unaltered in JAM-A(-/-) apoE(-/-) compared with JAM-A(-/-) apoE(-/-) lesions. In carotid arteries perfused ex vivo, deficiency in JAM-A significantly impaired the recruitment of monocytes 1 week, but not 1 day, after injury. These effects were paralleled by an attenuation of monocyte arrest and transmigration on activated JAM-A(-/-) apoE(-/-) versus JAM-A(-/-) apoE(-/-) endothelial cells under flow conditions in vitro. A mechanism underlying reduced recruitment was implied by findings that the luminal expression of the arrest chemokine RANTES in injured arteries and its endothelial deposition by activated platelets in vitro were diminished by JAM-A deficiency. Conclusions - Our data provide the first evidence to our knowledge for a crucial role of JAM-A in accelerated lesion formation and monocyte infiltration in atherosclerosis-prone mice

    Dimensional Reduction, Hard Thermal Loops and the Renormalization Group

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    We study the realization of dimensional reduction and the validity of the hard thermal loop expansion for lambda phi^4 theory at finite temperature, using an environmentally friendly finite-temperature renormalization group with a fiducial temperature as flow parameter. The one-loop renormalization group allows for a consistent description of the system at low and high temperatures, and in particular of the phase transition. The main results are that dimensional reduction applies, apart from a range of temperatures around the phase transition, at high temperatures (compared to the zero temperature mass) only for sufficiently small coupling constants, while the HTL expansion is valid below (and rather far from) the phase transition, and, again, at high temperatures only in the case of sufficiently small coupling constants. We emphasize that close to the critical temperature, physics is completely dominated by thermal fluctuations that are not resummed in the hard thermal loop approach and where universal quantities are independent of the parameters of the fundamental four-dimensional theory.Comment: 20 pages, 13 eps figures, uses epsfig and pstrick

    Statistical Survey of Type III Radio Bursts at Long Wavelengths Observed by the Solar TErrestrial RElations Observatory (STEREO)/Waves Instruments: Radio Flux Density Variations with Frequency

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    We have performed a statistical study of 152152 Type III radio bursts observed by Solar TErrestrial RElations Observatory (STEREO)/Waves between May 2007 and February 2013. We have investigated the flux density between 125125kHz and 1616MHz. Both high- and low-frequency cutoffs have been observed in 6060\,% of events suggesting an important role of propagation. As already reported by previous authors, we observed that the maximum flux density occurs at 11MHz on both spacecraft. We have developed a simplified analytical model of the flux density as a function of radial distance and compared it to the STEREO/Waves data.Comment: published in Solar Physic

    Isotopic and spin selectivity of H_2 adsorbed in bundles of carbon nanotubes

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    Due to its large surface area and strongly attractive potential, a bundle of carbon nanotubes is an ideal substrate material for gas storage. In addition, adsorption in nanotubes can be exploited in order to separate the components of a mixture. In this paper, we investigate the preferential adsorption of D_2 versus H_2(isotope selectivity) and of ortho versus para(spin selectivity) molecules confined in the one-dimensional grooves and interstitial channels of carbon nanotube bundles. We perform selectivity calculations in the low coverage regime, neglecting interactions between adsorbate molecules. We find substantial spin selectivity for a range of temperatures up to 100 K, and even greater isotope selectivity for an extended range of temperatures,up to 300 K. This isotope selectivity is consistent with recent experimental data, which exhibit a large difference between the isosteric heats of D_2 and H_2 adsorbed in these bundles.Comment: Paper submitted to Phys.Rev. B; 17 pages, 2 tables, 6 figure

    Filling a blank on the map: 60 years of fisheries in Equatorial Guinea

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    Despite a scarcity of pertinent information, it has been possible to reconstruct time series of marine fisheries catches for Equatorial Guinea from 1950 to 2010 using per capita fish consumption and population numbers for small-scale fisheries, catch rates and number of vessels for industrial fisheries and discard rates to estimate the discarded bycatch. Small-scale fisheries, industrial large-scale fisheries, domestic and legal and illegal foreign fisheries and their discards are all included. Total catches were estimated at 2.7 million tonnes over the time period considered, of which 653 000 t were caught domestically compared to 187 000 t reported by FAO. This shows that fisheries have more importance for Equatorial Guinea's food security than the official data suggest. In contrast to what is suggested by official figures, fisheries were shown to be strongly impacted by civil and political unrest; notably, they declined overall because of civil and political conflicts, socio-demographic dynamics, and a growing role of the newly discovered oil resources, which directly and indirectly threaten the food security of the people of Equatorial Guinea

    Search for an invisibly decaying Higgs boson in e^+e^- collisions at \sqrt{s} = 183 - 189 GeV

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    A search for a Higgs boson decaying into invisible particles is performed using the data collected at LEP by the L3 experiment at centre-of-mass energies of 183 GeV and 189 GeV. The integrated luminosities are respectively 55.3 pb^-1 and 176.4 pb^-1. The observed candidates are consistent with the expectations from Standard Model processes. In the hypothesis that the production cross section of this Higgs boson equals the Standard Model one and the branching ratio into invisible particles is 100%, a lower mass limit of 89.2 GeV is set at 95% confidence level

    Search for Extra Dimensions in Boson and Fermion Pair Production in e+e- Interactions at LEP

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    Extra spatial dimensions are proposed by recent theories that postulate the scale of gravity to be of the same order as the electroweak scale. A sizeable interaction between gravitons and Standard Model particles is then predicted. Effects of these new interactions in boson and fermion pair production are searched for in the data sample collected at centre-of-mass energies above the Z pole by the L3 detector at LEP. In addition, the direct production of a graviton associated with a Z boson is investigated. No statistically significant hints for the existence of these effects are found and lower limits in excess of 1 TeV are derived on the scale of this new theory of gravity

    Search for Heavy Neutral and Charged Leptons in e+ e- Annihilation at LEP

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    A search for exotic unstable neutral and charged heavy leptons as well as for stable charged heavy leptons is performed with the L3 detector at LEP. Sequential, vector and mirror natures of heavy leptons are considered. No evidence for their existence is found and lower limits on their masses are set

    Measurement of Hadron and Lepton-Pair Production at 130GeV < \sqrt{s} < 189 GeV at LEP

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    We report on measurements of e+e- annihilation into hadrons and lepton pairs. The data have been collected with the L3 detector at LEP at centre-of-mass energies between 130 and 189 GeV. Using a total integrated luminosity of 243.7 pb^-1, 25864 hadronic and 8573 lepton-pair events are selected for the measurement of cross sections and leptonic forward-backward asymmetries. The results are in good agreement with Standard Model predictions

    Search for Manifestations of New Physics in Fermion-Pair Production at LEP

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    The measurements of hadron and lepton-pair production cross sections and leptonic forward-backward asymmetries performed with the L3 detector at centre-of-mass energies between 130 GeV and 189 GeV are used to search for new physics phenomena such as: contact interactions, exchange of virtual leptoquarks, scalar quarks and scalar neutrinos, effects of TeV strings in models of quantum gravity with large extra dimensions and non-zero sizes of the fermions. No evidence for these phenomena is found and new limits on their parameters are set
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