2,350 research outputs found

    The magnetic environment of the Orion-Eridanus superbubble as revealed by Planck

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    Using the 353-GHz polarization observations by the Planck satellite we characterize the magnetic field in the Orion-Eridanus superbubble, a nearby expanding structure that spans more than 1600 square degrees in the sky. We identify a region of both low dispersion of polarization orientations and high polarization fraction associated with the outer wall of the superbubble identified in the most recent models of the large-scale shape of the region. We use the Davis-Chandrasekhar-Fermi method to derive plane-of-the-sky magnetic field strengths of tens of microGauss toward the southern edge of the bubble. The comparison of these values with existing Zeeman splitting observations of HI in emission suggests that the large-scale magnetic field in the region was primarily shaped by the expanding superbubble.Comment: 7 pages, 8 figures. Accepted for publication as a Letter in A&A, section 1. Letters to the Editor (08/12/2017

    Coupling of Transport and Chemical Processes in Catalytic Combustion

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    Catalytic combustors have demonstrated the ability to operate efficiently over a much wider range of fuel air ratios than are imposed by the flammability limits of conventional combustors. Extensive commercial use however needs the following: (1) the design of a catalyst with low ignition temperature and high temperature stability, (2) reducing fatigue due to thermal stresses during transient operation, and (3) the development of mathematical models that can be used as design optimization tools to isolate promising operating ranges for the numerous operating parameters. The current program of research involves the development of a two dimensional transient catalytic combustion model and the development of a new catalyst with low temperature light-off and high temperature stablity characteristics

    Perspectives of Nuclear Physics in Europe: NuPECC Long Range Plan 2010

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    The goal of this European Science Foundation Forward Look into the future of Nuclear Physics is to bring together the entire Nuclear Physics community in Europe to formulate a coherent plan of the best way to develop the field in the coming decade and beyond.<p></p> The primary aim of Nuclear Physics is to understand the origin, evolution, structure and phases of strongly interacting matter, which constitutes nearly 100% of the visible matter in the universe. This is an immensely important and challenging task that requires the concerted effort of scientists working in both theory and experiment, funding agencies, politicians and the public.<p></p> Nuclear Physics projects are often “big science”, which implies large investments and long lead times. They need careful forward planning and strong support from policy makers. This Forward Look provides an excellent tool to achieve this. It represents the outcome of detailed scrutiny by Europe’s leading experts and will help focus the views of the scientific community on the most promising directions in the field and create the basis for funding agencies to provide adequate support.<p></p> The current NuPECC Long Range Plan 2010 “Perspectives of Nuclear Physics in Europe” resulted from consultation with close to 6 000 scientists and engineers over a period of approximately one year. Its detailed recommendations are presented on the following pages. For the interested public, a short summary brochure has been produced to accompany the Forward Look.<p></p&gt

    Light deflection by gravitational waves from localized sources

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    We study the deflection of light (and the redshift, or integrated time delay) caused by the time-dependent gravitational field generated by a localized material source lying close to the line of sight. Our calculation explicitly takes into account the full, near-zone, plus intermediate-zone, plus wave-zone, retarded gravitational field. Contrary to several recent claims in the literature, we find that the deflections due to both the wave-zone 1/r gravitational wave and the intermediate-zone 1/r^2 retarded fields vanish exactly. The leading total time-dependent deflection caused by a localized material source, such as a binary system, is proven to be given by the quasi-static, near-zone quadrupolar piece of the gravitational field, and therefore to fall off as the inverse cube of the impact parameter.Comment: 12 pages, REVTeX 3.0, no figur

    Constraining relativistic models through heavy ion collisions

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    Relativistic models can be successfully applied to the description of compact star properties in nuclear astrophysics as well as to nuclear matter and finite nuclei properties, these studies taking place at low and moderate temperatures. Nevertheless, all results are model dependent and so far it is unclear whether some of them should be discarded. Moreover, in the regime of hot hadronic matter very few calculations exist using these relativistic models, in particular when applied to particle yields in heavy ion collisions. In the present work we comment on the known constraints that can help the selection of adequate models in this regime and investigate the main differences that arise when the particle production during a Au+Au collision at RHIC is calculated with different models.Comment: 9 pages, 1 figure, 3 table

    Single rooms may help to prevent nosocomial bloodstream infection and cross-transmission of methicillin-resistant Staphylococcus aureus in intensive care units

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    OBJECTIVE: Nosocomial infections remain a major problem in intensive care units. Several authorities have recommended housing patients in single rooms to prevent cross-transmission of potential pathogens, but this issue is currently debated. The aim of the present study was to compare the rate of nosocomial cross-contamination between patients hosted in single rooms versus bay rooms. DESIGN: Prospective observational data acquisition over 2.5 years. SETTING: A 14-bed medico-surgical ICU, composed of six single-bed rooms plus a six-bed and a two-bed bay room served by the same staff. PATIENTS AND PARTICIPANTS: All patients admitted from 1 July 2002 to 31 December 2004. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in admitted patients was 1.1% and acquisition rate 2.4%. The incidence density of MRSA acquisition was 4.1 [95% CI 2.7-6.3]/1,000 patient-days in bay rooms versus 1.3 [0.5-3.4]/1,000 patient-days in single rooms (p<0.001). Pseudomonas spp. acquisition rate was 3.9 [2.5-6.1]/1,000 patient-days in bay rooms versus 0.7 [0.2-2.4]/1,000 patient-days in single rooms (p<0.001), and Candida spp. colonization was 38.4 [33.3-44.1]/1,000 patient-days in bay rooms versus 13.8 [10.2-18.6]/1,000 patient-days (p<0.001). By multivariate analysis, the relative risk of MRSA, Pseudomonas aeruginosa and Candida spp. acquisition in single rooms or cubicles versus bay rooms was 0.65, 0.61 and 0.75 respectively. CONCLUSIONS: These data suggest that in an institution where MRSA is not hyperendemic, infection control measures may be more effective to prevent cross-transmission of microorganisms in patients housed in single rooms

    Hadronic Entropy Enhancement and Low Density QGP

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    Recent studies show that for central collisions the rising of the incident energy from AGS to RHIC decreases the value of the chemical potential in the Hadron-QGP phase diagram. Thus, the formation of QGP at RHIC energies in central collisions may be expected to occur at very small values of the chemical potential. Using many different relativistic mean-field hadronic models (RMF) at this regime we show that the critical temperature for the Hadron-QGP transition is hadronic model independent. We have traced back the reason for this and conclude that it comes from the fact that the QGP entropy is much larger than the hadronic entropy obtained in all the RMF models. We also find that almost all of these models present a strong entropy enhancement in the hadronic sector coming from the baryonic phase transition to a nucleon-antinucleon plasma. This result is in agreement with the recent data obtained in the STAR collaboration at RHIC where it was found a rich proton-antiproton matter
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