776 research outputs found

    On Asymptotic Expansion in the Random Allocation of Particles by Sets

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    We consider a scheme of equiprobable allocation of particles into cells by sets. The Edgeworth type asymptotic expansion in the local central limit theorem for a number of empty cells left after allocation of all sets of particles is derived.Comment: 15 page

    Perceptions of trekking tourism and social and environmental change in Nepal's Himalayas

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    The Himalayas are among the world’s youngest mountain ranges. In addition to the geologic processes of mountain building and erosion, they are also highly vulnerable to human influenced change, occurring at local, national, regional, and international scales. A photo-elicitation methodology is employed to show how residents perceive those changes from historical perspectives, as well as their current conditions and impacts on their daily lives. Nepal’s Khumbu region has undergone major social and environmental transformations since the 1960s when international trekking first began to influence the area's economy. The current perceptions of Khumbu residents of these changes is assessed through photo-elicitation interviews. Their responses are placed in the historical context of: (i) institutional and political changes, much of which have been driven by national government policies; (ii) social and economic changes, for which the tourism economy has been central; and (iii) environmental changes, reflecting the impacts of resource management and climate change. The mostly positive perceptions of Khumbu residents toward how their region has changed reflects general improvements in the physical and cultural landscapes of the Khumbu over time, as well as its continuing geographic isolation, which has helped to slow the rate of globalization, while also keeping the region a dynamic and popular tourist destination

    Shepherding sub-Saharan Africa's wildlife through peak anthropogenic pressure toward a green anthropocene

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    Sub-Saharan Africa’s (SSA’s) iconic biodiversity is of immense potential global value but is jeopardized by increasing anthropogenic pressures. Elevated consumption in wealthier countries and the demands of international corporations manifest in significant resource extraction from SSA. Biodiversity in SSA also faces increasing domestic pressures, including rapidly growing human populations. The demographic transition to lower fertility rates is occurring later and slower in SSA than elsewhere, and the continent’s human population may quadruple by 2100. SSA’s biodiversity will therefore pass through a bottleneck of growing anthropogenic pressures, while also experiencing intensifying effects of climate change. SSA’s biodiversity could be severely diminished over the coming decades and numerous species pushed to extinction. However, the prospects for nature conservation in SSA should improve in the long term, and we predict that the region will eventually enter a Green Anthropocene. Here, we outline critical steps needed to shepherd SSA’s biodiversity into the Green Anthropocene epoch.http://www.annualreviews.orgam2023Mammal Research InstituteZoology and Entomolog

    Global Search for New Physics with 2.0/fb at CDF

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    Data collected in Run II of the Fermilab Tevatron are searched for indications of new electroweak-scale physics. Rather than focusing on particular new physics scenarios, CDF data are analyzed for discrepancies with the standard model prediction. A model-independent approach (Vista) considers gross features of the data, and is sensitive to new large cross-section physics. Further sensitivity to new physics is provided by two additional algorithms: a Bump Hunter searches invariant mass distributions for "bumps" that could indicate resonant production of new particles; and the Sleuth procedure scans for data excesses at large summed transverse momentum. This combined global search for new physics in 2.0/fb of ppbar collisions at sqrt(s)=1.96 TeV reveals no indication of physics beyond the standard model.Comment: 8 pages, 7 figures. Final version which appeared in Physical Review D Rapid Communication

    Observation of Orbitally Excited B_s Mesons

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    We report the first observation of two narrow resonances consistent with states of orbitally excited (L=1) B_s mesons using 1 fb^{-1} of ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We use two-body decays into K^- and B^+ mesons reconstructed as B^+ \to J/\psi K^+, J/\psi \to \mu^+ \mu^- or B^+ \to \bar{D}^0 \pi^+, \bar{D}^0 \to K^+ \pi^-. We deduce the masses of the two states to be m(B_{s1}) = 5829.4 +- 0.7 MeV/c^2 and m(B_{s2}^*) = 5839.7 +- 0.7 MeV/c^2.Comment: Version accepted and published by Phys. Rev. Let

    Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

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    We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio
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