203 research outputs found

    Multi-Platform Detection of Small Ruminant Lentivirus Antibodies and Provirus as Biomarkers of Production Losses

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    Small ruminant lentiviruses (SRLVs) are endemic in most areas of Europe, causing a chronic infection and a multisystemic disease affecting the udder, carpal joints, lungs, and central nervous system. Due to the lack of treatments and protective vaccination strategies, infection control is focused on the identification of infected animals through serological or molecular techniques. However, antigenic and genetic heterogeneity of SRLVs represent a clear drawback for diagnosis. Infected animals may present lower animal production parameters such as birth weight or milk production and quality, depending on productive systems considered and, likely, to the diagnostic method applied. In this study, four sheep flocks dedicated to dairy or meat production were evaluated using three different ELISA and two PCR strategies to classify animal population according to SRLV infection status. Productive parameters were recorded along one whole lactation or reproductive period and compared between positive and negative animals. SRLV was present in 19% of the total population, being unequally distributed in the different flocks. Less than half of the infected animals were detected by a single diagnostic method, highlighting the importance of combining different diagnostic techniques. Statistical analysis employing animal classification using all the diagnostic methods associated lambing size, lamb weight at birth, and daily weight gain with SRLV infection status in meat flocks. Milk production, somatic cell count, fat, and protein content in the milk were associated with SRLV infection in dairy flocks, to a greater extent in the flock showing higher seroprevalence. A multi-platform SRLV diagnostic strategy was useful for ensuring correct animal classification, thus validating downstream studies investigating production traits

    Identification of Allosteric Modulators of Metabotropic Glutamate 7 Receptor Using Proteochemometric Modeling

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    Proteochemometric modeling (PCM) is a computational approach that can be considered an extension of quantitative structure–activity relationship (QSAR) modeling, where a single model incorporates information for a family of targets and all the associated ligands instead of modeling activity versus one target. This is especially useful for situations where bioactivity data exists for similar proteins but is scarce for the protein of interest. Here we demonstrate the application of PCM to identify allosteric modulators of metabotropic glutamate (mGlu) receptors. Given our long-running interest in modulating mGlu receptor function we compiled a matrix of compound-target bioactivity data. Some members of the mGlu family are well explored both internally and in the public domain, while there are much fewer examples of ligands for other targets such as the mGlu7 receptor. Using a PCM approach mGlu7 receptor hits were found. In comparison to conventional single target modeling the identified hits were more diverse, had a better confirmation rate, and provide starting points for further exploration. We conclude that the robust structure–activity relationship from well explored target family members translated to better quality hits for PCM compared to virtual screening (VS) based on a single target.FWN – Publicaties zonder aanstelling Universiteit Leide

    Measurements of long-range near-side angular correlations in sNN=5\sqrt{s_{\text{NN}}}=5TeV proton-lead collisions in the forward region

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    Two-particle angular correlations are studied in proton-lead collisions at a nucleon-nucleon centre-of-mass energy of sNN=5\sqrt{s_{\text{NN}}}=5TeV, collected with the LHCb detector at the LHC. The analysis is based on data recorded in two beam configurations, in which either the direction of the proton or that of the lead ion is analysed. The correlations are measured in the laboratory system as a function of relative pseudorapidity, Δη\Delta\eta, and relative azimuthal angle, Δϕ\Delta\phi, for events in different classes of event activity and for different bins of particle transverse momentum. In high-activity events a long-range correlation on the near side, Δϕ≈0\Delta\phi \approx 0, is observed in the pseudorapidity range 2.0<η<4.92.0<\eta<4.9. This measurement of long-range correlations on the near side in proton-lead collisions extends previous observations into the forward region up to η=4.9\eta=4.9. The correlation increases with growing event activity and is found to be more pronounced in the direction of the lead beam. However, the correlation in the direction of the lead and proton beams are found to be compatible when comparing events with similar absolute activity in the direction analysed.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-040.htm

    Study of the production of Λb0\Lambda_b^0 and B‟0\overline{B}^0 hadrons in pppp collisions and first measurement of the Λb0→J/ψpK−\Lambda_b^0\rightarrow J/\psi pK^- branching fraction

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    The product of the Λb0\Lambda_b^0 (B‟0\overline{B}^0) differential production cross-section and the branching fraction of the decay Λb0→J/ψpK−\Lambda_b^0\rightarrow J/\psi pK^- (B‟0→J/ψK‟∗(892)0\overline{B}^0\rightarrow J/\psi\overline{K}^*(892)^0) is measured as a function of the beauty hadron transverse momentum, pTp_{\rm T}, and rapidity, yy. The kinematic region of the measurements is pT<20 GeV/cp_{\rm T}<20~{\rm GeV}/c and 2.0<y<4.52.0<y<4.5. The measurements use a data sample corresponding to an integrated luminosity of 3 fb−13~{\rm fb}^{-1} collected by the LHCb detector in pppp collisions at centre-of-mass energies s=7 TeV\sqrt{s}=7~{\rm TeV} in 2011 and s=8 TeV\sqrt{s}=8~{\rm TeV} in 2012. Based on previous LHCb results of the fragmentation fraction ratio, fΛB0/fdf_{\Lambda_B^0}/f_d, the branching fraction of the decay Λb0→J/ψpK−\Lambda_b^0\rightarrow J/\psi pK^- is measured to be \begin{equation*} \mathcal{B}(\Lambda_b^0\rightarrow J/\psi pK^-)= (3.17\pm0.04\pm0.07\pm0.34^{+0.45}_{-0.28})\times10^{-4}, \end{equation*} where the first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the branching fraction of the decay B‟0→J/ψK‟∗(892)0\overline{B}^0\rightarrow J/\psi\overline{K}^*(892)^0, and the fourth is due to the knowledge of fΛb0/fdf_{\Lambda_b^0}/f_d. The sum of the asymmetries in the production and decay between Λb0\Lambda_b^0 and Λ‟b0\overline{\Lambda}_b^0 is also measured as a function of pTp_{\rm T} and yy. The previously published branching fraction of Λb0→J/ψpπ−\Lambda_b^0\rightarrow J/\psi p\pi^-, relative to that of Λb0→J/ψpK−\Lambda_b^0\rightarrow J/\psi pK^-, is updated. The branching fractions of Λb0→Pc+(→J/ψp)K−\Lambda_b^0\rightarrow P_c^+(\rightarrow J/\psi p)K^- are determined.Comment: 29 pages, 19figures. All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-032.htm

    Evidence for the strangeness-changing weak decay Ξb−→Λb0π−\Xi_b^-\to\Lambda_b^0\pi^-

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    Using a pppp collision data sample corresponding to an integrated luminosity of 3.0~fb−1^{-1}, collected by the LHCb detector, we present the first search for the strangeness-changing weak decay Ξb−→Λb0π−\Xi_b^-\to\Lambda_b^0\pi^-. No bb hadron decay of this type has been seen before. A signal for this decay, corresponding to a significance of 3.2 standard deviations, is reported. The relative rate is measured to be fΞb−fΛb0B(Ξb−→Λb0π−)=(5.7±1.8−0.9+0.8)×10−4{{f_{\Xi_b^-}}\over{f_{\Lambda_b^0}}}{\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) = (5.7\pm1.8^{+0.8}_{-0.9})\times10^{-4}, where fΞb−f_{\Xi_b^-} and fΛb0f_{\Lambda_b^0} are the b→Ξb−b\to\Xi_b^- and b→Λb0b\to\Lambda_b^0 fragmentation fractions, and B(Ξb−→Λb0π−){\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) is the branching fraction. Assuming fΞb−/fΛb0f_{\Xi_b^-}/f_{\Lambda_b^0} is bounded between 0.1 and 0.3, the branching fraction B(Ξb−→Λb0π−){\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) would lie in the range from (0.57±0.21)%(0.57\pm0.21)\% to (0.19±0.07)%(0.19\pm0.07)\%.Comment: 7 pages, 2 figures, All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-047.htm

    BB flavour tagging using charm decays at the LHCb experiment

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    An algorithm is described for tagging the flavour content at production of neutral BB mesons in the LHCb experiment. The algorithm exploits the correlation of the flavour of a BB meson with the charge of a reconstructed secondary charm hadron from the decay of the other bb hadron produced in the proton-proton collision. Charm hadron candidates are identified in a number of fully or partially reconstructed Cabibbo-favoured decay modes. The algorithm is calibrated on the self-tagged decay modes B+→J/ψ K+B^+ \to J/\psi \, K^+ and B0→J/ψ K∗0B^0 \to J/\psi \, K^{*0} using 3.0 fb−13.0\mathrm{\,fb}^{-1} of data collected by the LHCb experiment at pppp centre-of-mass energies of 7 TeV7\mathrm{\,TeV} and 8 TeV8\mathrm{\,TeV}. Its tagging power on these samples of B→J/ψ XB \to J/\psi \, X decays is (0.30±0.01±0.01)%(0.30 \pm 0.01 \pm 0.01) \%.Comment: All figures and tables, along with any supplementary material and additional information, are available at http://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-027.htm

    Identification of beauty and charm quark jets at LHCb

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    Identification of jets originating from beauty and charm quarks is important for measuring Standard Model processes and for searching for new physics. The performance of algorithms developed to select bb- and cc-quark jets is measured using data recorded by LHCb from proton-proton collisions at s=7\sqrt{s}=7 TeV in 2011 and at s=8\sqrt{s}=8 TeV in 2012. The efficiency for identifying a b(c)b(c) jet is about 65%(25%) with a probability for misidentifying a light-parton jet of 0.3% for jets with transverse momentum pT>20p_{\rm T} > 20 GeV and pseudorapidity 2.2<η<4.22.2 < \eta < 4.2. The dependence of the performance on the pTp_{\rm T} and η\eta of the jet is also measured

    Global maps of soil temperature.

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    Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km &lt;sup&gt;2&lt;/sup&gt; resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km &lt;sup&gt;2&lt;/sup&gt; pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications
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