749 research outputs found

    Effects of Concentrate Addition on In Vitro Rumen Fluid pH and Forage Fiber Digestion

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    Further characterization rumen digestion could aid in development of a more efficient diet. The objective was to determine the early effects (0-6h) of concentrate type on rumen pH and forage digestion. Two forages, orchard grass and corn (Zea mays L.) stover, were combined in a 50:50 ratio with 5 concentrate treatments (no concentrate, corn meal, corn gluten meal, barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.)). Samples were incubated in vitro in a 1:4 buffer to rumen fluid mixture for 420 min. The pH was measured at intervals throughout the trial and samples were collected for volatile fatty acid (VFA) analysis. Forage samples alone had significantly lower pH (P<0.05) than those samples containing concentrate. For corn stover samples, this correlates with a high mean lactic acid concentration (535 ppm). The final study measured change in pH and the difference in neutral detergent fiber (NDF) digestibility of four concentrate treatments (no concentrate, corn meal, corn gluten meal, and barley). Two sample distribution methods were tested; forage and concentrate were mixed together in the same filter bag or separated into individual bags. Barley had the largest inhibitory effect on fiber digestion and caused the largest decline in pH. Treatments with feeds in the same bag showed larger differences in pH and digestibility. Results suggest a diet containing a mixture of forages or, a mixture of corn and forage minimizes declines in rumen pH. They also suggest the study of associative effects is impeded by separation of feeds through filter bags

    Identifying challenges and opportunities for improved nutrient management through U.S.D.A's Dairy Agroecosystem Working Group

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    Nutrient management is a priority of U.S. dairy farms, although specific concerns vary across regions and management systems. To elucidate challenges and opportunities to improving nutrient use efficiencies, the USDA’s Dairy Agroecosystems Working Group investigated 10 case studies of confinement (including open lots and free stall housing) and grazing operations in the seven major U.S. dairy producing states. Simulation modeling was carried out using the Integrated Farm Systems Model over 25 years of historic weather data. Dairies with a preference for importing feed and exporting manure, common for simulated dry lot dairies of the arid west, had lower nutrient use efficiencies at the farm gate than freestall and tie-stall dairies in humid climates. Phosphorus (P) use efficiencies ranged from 33 to 82% of imported P, while N use efficiencies were 25 to 50% of imported N. When viewed from a P budgeting perspective, environmental losses of P were generally negligible, especially from dry lot dairies. Opportunities for greater P use efficiency reside primarily in increasing on-farm feed production and reducing excess P in diets. In contrast with P, environmental losses of nitrogen (N) were 50 to 75% of annual farm N inputs. For dry lot dairies, the greatest potential for N conservation is associated with ammonia (NH3) control from housing, whereas for freestall and tie-stall operations, N conservation opportunities vary with soil and manure management system. Given that fertilizer expenses are equivalent to 2 to 6% of annual farm profits, cost incentives do exist to improve nutrient use efficiencies. However, augmenting on-farm feed production represents an even greater opportunity, especially on large operations with high animal unit densities

    Making Every "Point" Count: Identifying the Key Determinants of Team Success in Elite Men’s Wheelchair Basketball

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    Wheelchair basketball coaches and researchers have typically relied on box score data and the Comprehensive Basketball Grading System to inform practice, however, these data do not acknowledge how the dynamic perspectives of teams change, vary and adapt during possessions in relation to the outcome of a game. Therefore, this study aimed to identify the key dynamic variables associated with team success in elite men’s wheelchair basketball and explore the impact of each key dynamic variable upon the outcome of performance through the use of binary logistic regression modelling. The valid and reliable template developed by Francis, Owen and Peters (2019) was used to analyse video footage in SportsCode from 31 games at the men’s 2015 European Wheelchair Basketball Championships. The 31 games resulted in 6,126 rows of data which were exported and converted into a CSV file, analysed using R (R Core Team 2015) and subjected to a data modelling process. Chi-square analyses identified significant (p<0.05) relationship between Game Outcome and 19 Categorical Predictor Variables. Automated stepwise binary regression model building was completed using 70% of the data (4,282 possessions) and produced a model that included 12 Categorical Predictor Variables. The accuracy of the developed model was deemed to be acceptable at accurately predicting the remaining 30% of the data (1,844 possessions) and produced an area under the receiver operating characteristic curve value of 0.759. The model identified the odds of winning are more than double when the team in possession are in a state of winning at the start of the possession are increased five-fold when the offensive team do not use a 1.0 or 1.5 classified player but are increased six-fold when the offensive team use three or more 3.0 or 3.5 players The final model can be used by coaches, players and support staff to devise training and game strategies that involve selecting the most appropriate offensive and defensive approaches when performing ball possessions to enhance the likelihood of winning in elite men’s wheelchair basketball

    Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

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    A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

    Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

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    A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

    Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at root s=13 TeV

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    Observation of tW production in the single-lepton channel in pp collisions at root s=13 TeV

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    A measurement of the cross section of the associated production of a single top quark and a W boson in final states with a muon or electron and jets in proton-proton collisions at root s = 13 TeV is presented. The data correspond to an integrated luminosity of 36 fb(-1) collected with the CMS detector at the CERN LHC in 2016. A boosted decision tree is used to separate the tW signal from the dominant t (t) over bar background, whilst the subleading W+jets and multijet backgrounds are constrained using data-based estimates. This result is the first observation of the tW process in final states containing a muon or electron and jets, with a significance exceeding 5 standard deviations. The cross section is determined to be 89 +/- 4 (stat) +/- 12 (syst) pb, consistent with the standard model.Peer reviewe

    Measurements of Higgs boson production cross sections and couplings in the diphoton decay channel at root s=13 TeV

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    Measurements of Higgs boson production cross sections and couplings in events where the Higgs boson decays into a pair of photons are reported. Events are selected from a sample of proton-proton collisions at root s = 13TeV collected by the CMS detector at the LHC from 2016 to 2018, corresponding to an integrated luminosity of 137 fb(-1). Analysis categories enriched in Higgs boson events produced via gluon fusion, vector boson fusion, vector boson associated production, and production associated with top quarks are constructed. The total Higgs boson signal strength, relative to the standard model (SM) prediction, is measured to be 1.12 +/- 0.09. Other properties of the Higgs boson are measured, including SM signal strength modifiers, production cross sections, and its couplings to other particles. These include the most precise measurements of gluon fusion and vector boson fusion Higgs boson production in several different kinematic regions, the first measurement of Higgs boson production in association with a top quark pair in five regions of the Higgs boson transverse momentum, and an upper limit on the rate of Higgs boson production in association with a single top quark. All results are found to be in agreement with the SM expectations.Peer reviewe

    Measurements of the Electroweak Diboson Production Cross Sections in Proton-Proton Collisions at root s=5.02 TeV Using Leptonic Decays

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    The first measurements of diboson production cross sections in proton-proton interactions at a center-of-mass energy of 5.02 TeV are reported. They are based on data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 302 pb(-1). Events with two, three, or four charged light leptons (electrons or muons) in the final state are analyzed. The WW, WZ, and ZZ total cross sections are measured as sigma(WW) = 37:0(-5.2)(+5.5) (stat)(-2.6)(+2.7) (syst) pb, sigma(WZ) = 6.4(-2.1)(+2.5) (stat)(-0.3)(+0.5)(syst) pb, and sigma(ZZ) = 5.3(-2.1)(+2.5)(stat)(-0.4)(+0.5) (syst) pb. All measurements are in good agreement with theoretical calculations at combined next-to-next-to-leading order quantum chromodynamics and next-to-leading order electroweak accuracy

    Search for lepton-flavor violating decays of the Higgs boson in the mu tau and e tau final states in proton-proton collisions at root s=13 TeV

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    A search is presented for lepton-flavor violating decays of the Higgs boson to mu t and et. The dataset corresponds to an integrated luminosity of 137 fb(-1) collected at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV. No significant excess has been found, and the results are interpreted in terms of upper limits on lepton-flavor violating branching fractions of the Higgs boson. The observed (expected) upper limits on the branching fractions are, respectively, B(H -> mu t) e tau) < 0.22(0.16)% at 95% confidence level.Peer reviewe
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