63,076 research outputs found

    Measurement of longitudinal spin asymmetries for weak boson production in polarized proton-proton collisions at RHIC

    Full text link
    We report measurements of single- and double- spin asymmetries for W±W^{\pm} and Z/γ∗Z/\gamma^* boson production in longitudinally polarized p+pp+p collisions at s=510\sqrt{s} = 510 GeV by the STAR experiment at RHIC. The asymmetries for W±W^{\pm} were measured as a function of the decay lepton pseudorapidity, which provides a theoretically clean probe of the proton's polarized quark distributions at the scale of the WW mass. The results are compared to theoretical predictions, constrained by recent polarized deep inelastic scattering measurements, and show a preference for a sizable, positive up antiquark polarization in the range 0.05<x<0.20.05<x<0.2.Comment: 7 pages, 5 figures, Submitted to Physical Review Letters; replaced with published versio

    Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV

    Get PDF
    The t t-bar production cross section (sigma[t t-bar]) is measured in proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS experiment, corresponding to an integrated luminosity of 2.3 inverse femtobarns. The measurement is performed in events with two leptons (electrons or muons) in the final state, at least two jets identified as jets originating from b quarks, and the presence of an imbalance in transverse momentum. The measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/- 2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction of the standard model.Comment: Replaced with published version. Included journal reference and DO

    Assessing the potential for knowledge-based development in transition countries. Bruegel Working Paper 2010/01, May 2010

    Get PDF
    This Working Paper by Bruegel Senior Fellow Reinhilde Veugelers examines the potential for a knowledge-based growth path in transition countries of central and eastern Europe, the Caucasus and Central Asia. The paper looks closely at how total-factor productivity, a residual growth factor commonly interpreted as reflecting technological progress, drives growth rates in these economies which exhibit a much lower GDP per capita compared to the EU15 or the United States. By analysing the prerequisites for knowledge-based growth, the author explains why transition countries are at a systemic disadvantage relative to the EU15, US and Japan and have limited potential for knowledge-based growth

    A Global Database of Domestic and International Tourist Numbers at National and Subnational Level

    Get PDF
    We present a new, global data base on tourist destinations. The data base differs from other data bases in that it includes both domestic and international tourists; and it contains data, for the most important destinations, data at national level as well as at lower administrative levels. Missing observations are interpolated using statistical models. The data are freely accessible on the internet.Tourism, Data

    Global patterns of renewable energy innovation, 1990–2009

    Get PDF
    Cost-effective approaches to mitigating climate change depend on advances in clean energy technologies, such as solar and wind power. Given increased technology innovation in developing countries, led by China, we focus our attention on global patterns of renewable energy innovation. Utilizing highly valuable international patents as our indicator of innovation, we examine the economic and political determinants of energy innovation in 74 countries across the world, 1990–2009. We find that high oil prices and domestic renewable electricity generation capacity both increase innovation. There is no effect for corruption, but our findings suggest that democratic institutions may contribute to innovation. The main implication of our work for policymakers is that increasing renewable electricity capacity in developing countries could significantly contribute to global innovation in renewable energy

    Strangelet Search in AuAu Collisions at 200 GeV

    Get PDF
    We have searched for strangelets in a triggered sample of 61 million central (top 4%) Au+Au collisions at \sNN = 200 GeV near beam rapidities at the STAR detector. We have sensitivity to metastable strangelets with lifetimes of order ≄0.1ns\geq 0.1 ns, in contrast to limits over ten times longer in AGS studies and longer still at the SPS. Upper limits of a few 10^{-6} to 10^{-7} per central Au+Au collision are set for strangelets with mass ∌>30{}^{>}_{\sim}30 GeV/c^{2}.Comment: As publishe

    Evaluation of Microencapsulation of The UFV-AREG1 Bacteriophage in Alginate-Ca Microcapsules using Microfluidic Devices

    Full text link
    The indiscriminate use of antibiotics and the emergence of resistant microorganisms have become a major challenge for the food industry. The purpose of this work was to microencapsulate the bacteriophage UFV-AREG1 in a calcium alginate matrix using microfluidic devices and to study the viability and efficiency of retention. The microcapsules were added to gel of propylene glycol for use as an antimicrobial in the food industry. The technique showed the number of the phage encapsulation, yielding drops with an average 100-250 Ό\mum of diameter, 82.1 ±\pm 2% retention efficiency and stability in the gel matrix for 21 days. The gel added to the microencapsulated phage showed efficiency (not detectable on the surface) in reducing bacterial contamination on the surface at a similar level to antimicrobial chemicals (alcohol 70%). Therefore, it was possible to microencapsulate bacteriophages in alginate-Ca and apply the microcapsules in gels for use as sanitizers in the food industry.Comment: 8 pages, 5 figure
    • 

    corecore