118 research outputs found

    Data-driven Planning for the Conservation of Grassland Birds in the Central Hardwoods Bird Conservation Region

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    The Central Hardwoods Joint Venture held two workshops in 2006 to delineate bobwhite focus areas across the Central Hardwoods Bird Conservation Region (BCR) for targeting on-the-ground conservation efforts. From 2008 – 2012, we conducted randomized sets of point counts within counties containing bobwhite focal areas to assess the efficacy of that method for monitoring grassland birds within focal areas, and to assess relationships of conservation practices with bird species occupancy and abundance. We collected data on nine species of Partners in Flight priority species, including northern bobwhite (Colinus virginianus). Land cover types within a 200-m buffer of each point were derived from year National Agricultural Statistics Service data, and information related to the location of conservation practices deemed beneficial to grassland birds was attained from the National Resources Conservation Service. We fit occupancy and abundance models for each species using Akaike’s Information Criterion adjusted for small sample sizes. We then used the model covariates to map predicted abundances of three species, northern bobwhite, eastern meadowlark (Sturnella magna), and Henslow’s sparrow (Ammodramus henslowii) across the BCR. The spatial patterns of predicted abundance varied among species, suggesting that focus areas should be somewhat species-specific. We will use data collected around the nests of each species at Ft. Campbell, a military base straddling the Kentucky-Tennessee border where grassland management has occurred at relatively large scales over more than two decades, to assess the with-in patch structure preferred by each species to develop grazing practices that will result in the desired structure for the species suite

    Measurement of the diffractive structure function in deep inelastic scattering at HERA

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    This paper presents an analysis of the inclusive properties of diffractive deep inelastic scattering events produced in epep interactions at HERA. The events are characterised by a rapidity gap between the outgoing proton system and the remaining hadronic system. Inclusive distributions are presented and compared with Monte Carlo models for diffractive processes. The data are consistent with models where the pomeron structure function has a hard and a soft contribution. The diffractive structure function is measured as a function of \xpom, the momentum fraction lost by the proton, of β\beta, the momentum fraction of the struck quark with respect to \xpom, and of Q2Q^2. The \xpom dependence is consistent with the form \xpoma where a = 1.30 ± 0.08 (stat)  0.14+ 0.08 (sys)a~=~1.30~\pm~0.08~(stat)~^{+~0.08}_{-~0.14}~(sys) in all bins of β\beta and Q2Q^2. In the measured Q2Q^2 range, the diffractive structure function approximately scales with Q2Q^2 at fixed β\beta. In an Ingelman-Schlein type model, where commonly used pomeron flux factor normalisations are assumed, it is found that the quarks within the pomeron do not saturate the momentum sum rule.Comment: 36 pages, latex, 11 figures appended as uuencoded fil

    Observation of hard scattering in photoproduction events with a large rapidity gap at HERA

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    Events with a large rapidity gap and total transverse energy greater than 5 GeV have been observed in quasi-real photoproduction at HERA with the ZEUS detector. The distribution of these events as a function of the γp\gamma p centre of mass energy is consistent with diffractive scattering. For total transverse energies above 12 GeV, the hadronic final states show predominantly a two-jet structure with each jet having a transverse energy greater than 4 GeV. For the two-jet events, little energy flow is found outside the jets. This observation is consistent with the hard scattering of a quasi-real photon with a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil

    Observation of direct processes in photoproduction at HERA

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    Jets in photoproduction events have been studied with the ZEUS detector for gammap centre-of-mass energies ranging from 130 to 2 50 GeV. The inclusive jet distributions give evidence for the dominance of resolved photon interactions. In the di-jet sample the direct processes are for the first time clearly isolated. Di-jet cross sections for the resolved and direct processes are given in a restricted kinematic range

    Measurement of the F2 structure function in deep inelastic e+^{+}p scattering using 1994 data from the ZEUS detector at HERA

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    We present measurements of the structure function \Ft\ in e^+p scattering at HERA in the range 3.5\;\Gevsq < \qsd < 5000\;\Gevsq. A new reconstruction method has allowed a significant improvement in the resolution of the kinematic variables and an extension of the kinematic region covered by the experiment. At \qsd < 35 \;\Gevsq the range in x now spans 6.3\cdot 10^{-5} < x < 0.08 providing overlap with measurements from fixed target experiments. At values of Q^2 above 1000 GeV^2 the x range extends to 0.5. Systematic errors below 5\perc\ have been achieved for most of the kinematic urray, W

    Measurement of Elastic ϕ\phi Photoproduction at HERA

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    The production of ϕ\phi mesons in the reaction e+pe+ϕpe^{+}p \rightarrow e^{+} \phi p (ϕK+K\phi \rightarrow K^{+}K^{-}) at a median Q2Q^{2} of $10^{-4} \ \rm{GeV^2}hasbeenstudiedwiththeZEUSdetectoratHERA.Thedifferential has been studied with the ZEUS detector at HERA. The differential \phiphotoproductioncrosssection photoproduction cross section d\sigma/dthasanexponentialshapeandhasbeendeterminedinthekinematicrange has an exponential shape and has been determined in the kinematic range 0.1<|t|<0.5 \ \rm{GeV^2}and and 60 < W < 80 \ \rm{GeV}.Anintegratedcrosssectionof. An integrated cross section of \sigma_{\gamma p \rightarrow \phi p} = 0.96 \pm 0.19^{+0.21}_{-0.18} \rm{\mu b}hasbeenobtainedbyextrapolatingtot=0.Whencomparedtolowerenergydata,theresultsshowaweakenergydependenceofboth has been obtained by extrapolating to {\it t} = 0. When compared to lower energy data, the results show a weak energy dependence of both \sigma_{\gamma p \rightarrow \phi p}andtheslopeofthe and the slope of the tdistribution.The distribution. The \phidecayangulardistributionsareconsistentwith decay angular distributions are consistent with schannelhelicityconservation.FromlowerenergiestoHERAenergies,thefeaturesof-channel helicity conservation. From lower energies to HERA energies, the features of \phi$ photoproduction are compatible with those of a soft diffractive process.Comment: 23 pages, including 6 post script figure

    Observation of Events with an Energetic Forward Neutron in Deep Inelastic Scattering at HERA

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    In deep inelastic neutral current scattering of positrons and protons at the center of mass energy of 300 GeV, we observe, with the ZEUS detector, events with a high energy neutron produced at very small scattering angles with respect to the proton direction. The events constitute a fixed fraction of the deep inelastic, neutral current event sample independent of Bjorken x and Q2 in the range 3 · 10-4 \u3c xBJ \u3c 6 · 10-3 and 10 \u3c Q2 \u3c 100 GeV2

    The role of unintegrated DNA in HIV infection

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    Integration of the reverse transcribed viral genome into host chromatin is the hallmark of retroviral replication. Yet, during natural HIV infection, various unintegrated viral DNA forms exist in abundance. Though linear viral cDNA is the precursor to an integrated provirus, increasing evidence suggests that transcription and translation of unintegrated DNAs prior to integration may aid productive infection through the expression of early viral genes. Additionally, unintegrated DNA has the capacity to result in preintegration latency, or to be rescued and yield productive infection and so unintegrated DNA, in some circumstances, may be considered to be a viral reservoir. Recently, there has been interest in further defining the role and function of unintegrated viral DNAs, in part because the use of anti-HIV integrase inhibitors leads to an abundance of unintegrated DNA, but also because of the potential use of non-integrating lentiviral vectors in gene therapy and vaccines. There is now increased understanding that unintegrated viral DNA can either arise from, or be degraded through, interactions with host DNA repair enzymes that may represent a form of host antiviral defence. This review focuses on the role of unintegrated DNA in HIV infection and additionally considers the potential implications for antiviral therapy

    Measurement of Charged and Neutral Current e-p Deep Inelastic Scattering Cross Sections at High Q2

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    Deep inelastic e-p scattering has been studied in both the charged current (CC) and neutral current (NC) reactions at momentum transfers squared Q(2) above 400 GeV2 using the ZEUS detector at the HERA ep collider. The CC and NC total cross sections, the NC to CC cross section ratio, and the differential cross sections d sigma/dQ(2) are presented. From the Q(2) dependence of the CC cross section, the mass term in the CC propagator is determined to be M(W) = 76 +/- 16 +/- 13 GeV

    Extraction of the gluon density of the proton at x

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