1,069 research outputs found

    Palaeobiology, ecology, and distribution of stromatoporoid faunas in biostromes of the mid-Ludlow of Gotland

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    Six well exposed mid−Ludlow stromatoporoid−dominated reef biostromes in four localities from the Hemse Group in southeastern Gotland, Sweden comprise a stromatoporoid assemblage dominated by four species; Clathrodictyon mohicanum, “Stromatopora” bekkeri, Plectostroma scaniense, and Lophiostroma schmidtii. All biostromes investigated in this area (of approximately 30 km2) are interpreted to belong to a single faunal assemblage forming a dense accumulation of fossils that is probably the best exposed stromatoporoid−rich deposit of the Silurian. The results from this comprehensive study strengthen earlier interpretations of a combination of genetic and environmental control on growth−forms of the stromatoporoids. Growth styles are similar for stromatoporoids in all six biostromes. Differences in biostrome fabric are due to variations in the degree of disturbance by storms. The uniformity of facies and the widespread low−diversity fauna support the view that palaeoenvironmental conditions were similar across the area where these biostromes crop out, and promoted the extraordinary growth of stromatoporoids in this shallow shelf area

    The Level and Distribution of Global Household Wealth

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    We estimate the level and distribution of global household wealth. The levels of assets and debts for 39 countries are measured using household balance sheet and survey data centred on the year 2000. The determinants of mean financial assets, non-financial assets, and liabilities are studied empirically, and the results used to estimate average wealth holdings for countries lacking direct evidence. Data on the pattern of household distribution of wealth are assembled for 20 countries, which together account for 59 per cent of the global population and 75 per cent of global wealth. The observed relation between wealth and income distribution in these 20 countries allows estimates of wealth inequality to be produced for many other nations. Combining the figures for individual countries reveals that net worth averaged US44,024peradultinPPPtermsacrosstheglobe.WealthofUS44,024 per adult in PPP terms across the globe. Wealth of US8,635 was needed to be in the top half of the global distribution, and US$518,364 to be in the top one per cent. The top 10 per cent owned 71 per cent of world wealth, and the Gini coefficient for the global distribution of wealth is estimated to be 0.802, indicating greater inequality than that observed in the global distribution of consumption or income.

    Recent Heavy Ion Results with the ATLAS Detector at the LHC

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    Results are presented from the ATLAS collaboration from the 2010 LHC heavy ion run, during which nearly 10 inverse microbarns of luminosity were delivered. Soft physics results include charged particle multiplicities and collective flow. The charged particle multiplicity, which tracks initial state entropy production, increases by a factor of two relative to the top RHIC energy, with a centrality dependence very similar to that already measured at RHIC. Measurements of elliptic flow out to large transverse momentum also show similar results to what was measured at RHIC, but no significant pseudorapidity dependence. Extensions of these measurements to higher harmonics have also been made, and can be used to explain structures in the two-particle correlation functions that had long been attributed to jet-medium interactions. New hard probe measurements include single muons, jets and high pTp_T hadrons. Single muons at high momentum are used to extract the yield of W±W^{\pm} bosons and are found to be consistent within statistical uncertainties with binary collision scaling. Conversely, jets are found to be suppressed in central events by a factor of two relative to peripheral events, with no significant dependence on the jet energy. Fragmentation functions are also found to be the same in central and peripheral events. Finally, charged hadrons have been measured out to 30 GeV, and their centrality dependence relative to peripheral events is similar to that found for jets.Comment: 9 pages, 9 figures, proceedings for Quark Matter 2011, Annecy, France, May 23-28, 201

    NMR investigations of interactions between anesthetics and lipid bilayers

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    Interactions between anesthetics (lidocaine and short chain alcohols) and lipid membranes formed by dimyristoylphosphatidylcholine (DMPC) were studied using NMR spectroscopy. The orientational order of lidocaine was investigated using deuterium NMR on a selectively labelled compound whereas segmental ordering in the lipids was probed by two-dimensional 1H-13C separated local field experiments under magic-angle spinning conditions. In addition, trajectories generated in molecular dynamics (MD) computer simulations were used for interpretation of the experimental results. Separate simulations were carried out with charged and uncharged lidocaine molecules. Reasonable agreement between experimental dipolar interactions and the calculated counterparts was observed. Our results clearly show that charged lidocaine affects significantly the lipid headgroup. In particular the ordering of the lipids is increased accompanied by drastic changes in the orientation of the P-N vector in the choline group
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