6,054 research outputs found

    Drell-Yan, ZZ, W+W- production in SM & ADD model to NLO+PS accuracy at the LHC

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    In this paper, we present the next-to-leading order QCD corrections for di-lepton, di-electroweak boson (ZZ, W+W-) production in both the SM and the ADD model, matched to the HERWIG parton-shower using the aMC@NLO framework. A selection of results at the 8 TeV LHC, which exhibits deviation from the SM as a result of the large extra-dimension scenario are presented.Comment: 12 pages, 10 figures, search sensitivity for the 14 TeV LHC discussed, version to appear in Eur. Phys. J.

    REDUCING PHOSPHORUS POLLUTION IN THE MINNESOTA RIVER: HOW MUCH IS IT WORTH?

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    A mail survey was conducted in Minnesota in 1997 to estimate the value of reducing phosphorus levels in the Minnesota River by 40%. The general population survey of river basin residents was designed to gather information about respondents' use of the Minnesota River in addition to their valuation of a hypothetical water quality improvement program. An estimate of the value of a specific recreational site along the River, the Minnesota Valley National Wildlife Refuge, was also obtained. Three distinct models were estimated in this research. The first was a contingent valuation model estimating the willingness to pay (WTP) for water quality improvements in the Minnesota River using only stated preference data. There were two different payment vehicles used in this question, an increase in the state income tax and a water bill surcharge. Respondents' annual mean willingness to pay for a 40% reduction in phosphorus was estimated to be 14.07usingthismodelandthetaxvehicle,whilethemeanwillingnesstopayviathewaterbillsurchargewasestimatedtobe14.07 using this model and the tax vehicle, while the mean willingness to pay via the water bill surcharge was estimated to be 19.64 annually. The second model utilized stated preference data from respondents along with responses about their actual visit behavior. A panel model was constructed using the responses to three separate questions concerning the value of a 40% reduction in phosphorus pollution and yielded an estimate of 38.88peryear.ThefinalmodelusedonlydatafromthesubsetofrespondentswhohadactuallyvisitedtheMinnesotaValleyNationalWildlifeRefuge.TherecreationalvalueofatypicaltriptotheRefugewasestimatedtobe38.88 per year. The final model used only data from the subset of respondents who had actually visited the Minnesota Valley National Wildlife Refuge. The recreational value of a typical trip to the Refuge was estimated to be 28.71 per individual.Environmental Economics and Policy,

    Revised Relativistic Hydrodynamical Model for Neutron-Star Binaries

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    We report on numerical results from a revised hydrodynamic simulation of binary neutron-star orbits near merger. We find that the correction recently identified by Flanagan significantly reduces but does not eliminate the neutron-star compression effect. Although results of the revised simulations show that the compression is reduced for a given total orbital angular momentum, the inner most stable circular orbit moves to closer separation distances. At these closer orbits significant compression and even collapse is still possible prior to merger for a sufficiently soft EOS. The reduced compression in the corrected simulation is consistent with other recent studies of rigid irrotational binaries in quasiequilibrium in which the compression effect is observed to be small. Another significant effect of this correction is that the derived binary orbital frequencies are now in closer agreement with post-Newtonian expectations.Comment: Submitted to Phys. Rev.

    Educational Games & Health Sciences

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    This webinar will begin with an overview of educational games and their benefits. Rina Wehbe, University of Waterloo, will speak about her research and recent game “Above Water” which informs people about strategies for coping with anxiety. Zeb Mathews, University of Tennessee, will speak about his game, “PubWizard” which quizzes graduate level informatics students\u27 knowledge of primary and secondary sources. This will be followed by an interactive exercise of exploring some of the National Institutes of Health (NIH) & National Library of Medicine (NLM) endorsed games. A Q&A session will follow. Are you interested in creating a game? We’ll have an exit survey to discuss hosting a game creation course. The learning objectives currently include the following: - Understand how educational games and gamification are unique - Learn about the possible benefits and advantages of learning with games - Better general understanding of the process of creating an educational game - Become acquainted with 2 educational games that intersect with the health sciences - Understand how basic game design elements are significant in educational games - Become familiar with some NIH & NLM endorsed games Outline:Introduction/Overview: 5-10 min.Rina Wehbe (Above Water): 20 min.Zeb Mathews (PubWizard): 20 min.Game Exercise: 15-20 min.Q&A & Survey: 5–10 min

    DCO+^+, DCN and N2_2D+^+ reveal three different deuteration regimes in the disk around the Herbig Ae star HD163296

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    The formation pathways of deuterated species trace different regions of protoplanetary disks and may shed light into their physical structure. We aim to constrain the radial extent of main deuterated species; we are particularly interested in spatially characterizing the high and low temperature pathways for enhancing deuteration of these species. We observed the disk surrounding the Herbig Ae star HD 163296 using ALMA in Band 6 and obtained resolved spectral imaging data of DCO+^+ (JJ=3-2), DCN (JJ=3-2) and N2_2D+^+ (JJ=3-2). We model the radial emission profiles of DCO+^+, DCN and N2_2D+^+, assuming their emission is optically thin, using a parametric model of their abundances and radial excitation temperature estimates. DCO+^+ can be described by a three-region model, with constant-abundance rings centered at 70 AU, 150 AU and 260 AU. The DCN radial profile peaks at about ~60 AU and N2_2D+^+ is seen in a ring at ~160 AU. Simple models of both molecules using constant abundances reproduce the data. Assuming reasonable average excitation temperatures for the whole disk, their disk-averaged column densities (and deuterium fractionation ratios) are 1.6-2.6×1012\times 10^{12} cm2^{-2} (0.04-0.07), 2.9-5.2×1012\times 10^{12} cm2^{-2} (\sim0.02) and 1.6-2.5 ×1011\times 10^{11} cm2^{-2} (0.34-0.45) for DCO+^+, DCN and N2_2D+^+, respectively. Our simple best-fit models show a correlation between the radial location of the first two rings in DCO+^+ and the DCN and N2_2D+^+ abundance distributions that can be interpreted as the high and low temperature deuteration pathways regimes. The origin of the third DCO+^+ ring at 260 AU is unknown but may be due to a local decrease of ultraviolet opacity allowing the photodesorption of CO or due to thermal desorption of CO as a consequence of radial drift and settlement of dust grains

    Possible explanation for star-crushing effect in binary neutron star simulations

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    A possible explanation is suggested for the controversial star-crushing effect seen in numerical simulations of inspiraling neutron star binaries by Wilson, Mathews and Marronetti (WMM). An apparently incorrect definition of momentum density in the momentum constraint equation used by WMM gives rise to a post-1-Newtonian error in the approximation scheme. We show by means of an analytic, post-1-Newtonian calculation that this error causes an increase of the stars' central densities which is of the order of several percent when the stars are separated by a few stellar radii, in agreement with what is seen in the simulations.Comment: 4 pages, 1 figure, uses revetx macros, minor revision

    Irrotational binary neutron stars in quasiequilibrium

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    We report on numerical results from an independent formalism to describe the quasi-equilibrium structure of nonsynchronous binary neutron stars in general relativity. This is an important independent test of controversial numerical hydrodynamic simulations which suggested that nonsynchronous neutron stars in a close binary can experience compression prior to the last stable circular orbit. We show that, for compact enough stars the interior density increases slightly as irrotational binary neutron stars approach their last orbits. The magnitude of the effect, however, is much smaller than that reported in previous hydrodynamic simulations.Comment: 4 pages, 2 figures, revtex, accepted for publication in Phys. Rev.
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