302 research outputs found

    Very Cold Gas and Dark Matter

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    We have recently proposed a new candidate for baryonic dark matter: very cold molecular gas, in near-isothermal equilibrium with the cosmic background radiation at 2.73 K. The cold gas, of quasi-primordial abundances, is condensed in a fractal structure, resembling the hierarchical structure of the detected interstellar medium. We present some perspectives of detecting this very cold gas, either directly or indirectly. The H2_2 molecule has an "ultrafine" structure, due to the interaction between the rotation-induced magnetic moment and the nuclear spins. But the lines fall in the km domain, and are very weak. The best opportunity might be the UV absorption of H2_2 in front of quasars. The unexpected cold dust component, revealed by the COBE/FIRAS submillimetric results, could also be due to this very cold H2_2 gas, through collision-induced radiation, or solid H2_2 grains or snowflakes. The γ\gamma-ray distribution, much more radially extended than the supernovae at the origin of cosmic rays acceleration, also points towards and extended gas distribution.Comment: 16 pages, Latex pages, crckapb macro, 3 postscript figures, uuencoded compressed tar file. To be published in the proceeedings of the "Dust-Morphology" conference, Johannesburg, 22-26 January, 1996, D. Block (ed.), (Kluwer Dordrecht

    A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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    Health risk associated with airborne asbestos

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    The following paper presents an assessment of health risks associated with air polluted with respirable asbestos fibers in towns of southwest Poland. The aim of the work was to determine whether or not any prevention measures are necessary in order to reduce the level of exposure to the pollutant. The risk assessment was carried out based on the air analyses and the latest asbestos toxicity data published by the Environmental Protection Agency (US EPA), USA and Office of Environmental Health Hazard Assessment (OEHHA). It was found that in some sites, the concentration of the asbestos fibers exceeded the acceptable levels, which should be a reason of special concern. The highest concentration of asbestos was found in town centers during the rush hours. In three spots, the calculated maximum health risk exceeded 1E-04 which is considered too high according to the adopted standards. So far, it has not yet been possible to find a reasonable method of ensuring the hazard reduction

    Sizing Up the Impact of Embassies on Exports

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    The purpose of this study is to test for the effects of trade promotion via the foreign service. We develop a Melitz-based model where firms are heterogeneous with respect to productivity and must pay a beachhead cost to enter a foreign market, which can be reduced by government spending on trade promotion. The model predicts that unilateral trade promotion allows medium-sized firms to export. We test this prediction using Swedish firm-level data and information on the opening and closing of Swedish embassies abroad using Norwegian firms as control group. Our results lend support to the predictions of the model, with large and medium-sized firms responding most strongly to the opening of embassies

    Infrastructure and Trade

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    This paper explores the role that quality of infrastructure has on a country's trade performance, estimating a gravity model that incorporates bilateral tariffs and a number of indicators for the quality of infrastructure. The paper looks at the impact of the quality of infrastructure (road, airport, port and telecommunication, and the time required for customs clearance) on total bilateral trade and on trade in the automotive, clothing and textile sectors. In order to obtain unbiased estimators, multilateral resistances for tariffs and remoteness are introduced in the gravity equation. Moreover, the robustness of the results is tested by estimating a fixed-effect model, where bilateral indexes of the quality of infrastructure are included. The results can be summarised in four main findings: (i) bilateral tariffs, generally neglected in gravity regression of bilateral flows, have a significant negative impact on trade; (ii) quality of infrastructure is an important determinant of trade performance; (iii) port efficiency appears to have the largest impact on trade among all indicators of infrastructure; (iv) timeliness and access to telecommunication are relatively more important for export competitiveness in the clothing and automotive sector respectively
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