190 research outputs found

    Evaluation of neutral detergent fiber contents in forages, concentrates and cattle feces ground at different particle sizes and using bags made from different textiles

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    Two experiments were carried out to evaluate the effects of particles sizes on contents of neutral detergent fiber (NDF) by using nylon bags F57 (Ankom®) and non-woven textile (NWT 100 g/m²). In the first experiment, to check contents of NDF obtained with each one of the textilles, quantitative filter paper (purified cellulose) was used as analytical standard. The material was processed in a 1 or 2 mm and put in the bags in a ratio of 20 mg of dry matter/cm² of surface. The analyses were performed in a fiber analyser (Ankom220) and using a heat-stable a-amylase. No effects of particles sizes were found. In the second experiment, it was used samples of forage (signal grass hay, sugar cane, coastcross hay, corn straw, corn silage, and elephant grass at 50 and 250 days of growing after cutting), concentrate feeds (sorghum grain, gluten meal, citrus pulp, cottonseed meal, soybean meal, wheat bran, corn grain, whole soybean, and soybean hulls), and feces of cattle of animals fed diets containing 15 or 50% of concentrate. The samples were prepared, put in bags, and analyzed as described in the previous experiment. In both experiments, the smallest contents of NDF were found by using nylon bags, indicating loss of particles through the bag porosity. It is suggested grind of samples by using 1-mm screen sieve, which provides efficient extraction of cell content by the action of neutral detergent and a greater specific surface by the action of the heat-stable a-amylase enzyme. The use of particles ground at 2-mm overestimates NDF contents.Foram realizados dois experimentos objetivando-se avaliar a influência do tamanho das partículas sobre os teores de fibra em detergente neutro (FDN) utilizando-se sacos de náilon, F57 (Ankom®) e tecido-não-tecido (TNT 100 g/m²). No primeiro experimento, com o intuito de aferir os teores de FDN obtidos com cada um dos tecidos, utilizou-se papel-filtro quantitativo (celulose purificada) como padrão analítico. O material foi processado em 1 e 2 mm e acondicionado nos sacos seguindo-se a relação de 20 mg de matéria seca/cm² de superfície. Utilizou-se aparelho analisador de fibras (Ankom220), empregando-se a-amilase termoestável. Não foram verificados efeitos do tamanho de partículas. Contudo, perdas de partículas significativas foram verificadas com o uso do náilon. No segundo experimento foram utilizadas amostras de forragem (feno de capim-braquiária, cana-de-açúcar, feno de coastcross, palha de milho, silagem de milho e capim-elefante cortado aos 50 dias e 250 dias de rebrotação), alimentos concentrados (sorgo grão, glúten de milho, polpa cítrica, farelo de algodão, farelo de soja, farelo de trigo, milho grão, soja grão e casca de soja) e fezes bovinas oriundas de animais alimentados com dietas contendo 15 e 50% de concentrado. As amostras foram preparadas, acondicionadas e analisadas como descrito no experimento anterior. Os menores teores de FDN foram encontrados com o uso de sacos de náilon, o que indica perda de partículas pela porosidade do saco. Recomenda-se a moagem de amostras em peneiras de porosidade 1 mm, o que propicia a extração eficiente do conteúdo celular pela ação do detergente neutro e maior superfície específica para ação da a-amilase termoestável. O uso de partículas processadas a 2 mm conduz à superestimação dos teores de FDN

    Efeitos da frequência de fornecimento do volumoso e concentrado no comportamento ingestivo de vacas e novilhas em confinamento

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    Este estudo foi conduzido com o objetivo de avaliar a influência da frequência no fornecimento de volumoso e concentrado e/ou da categoria animal sobre o comportamento ingestivo de bovinos. Foram utilizadas 16 novilhas e 16 vacas com idade média inicial de 20 e 66 meses e peso médio inicial de 338 e 432 kg, respectivamente. Os tratamentos foram representados pelas frequências de fornecimento do volumoso e do concentrado: 2 V/C - volumoso e concentrado duas vezes ao dia; 1 V/C - volumoso e concentrado uma vez ao dia; 1 V/2 C - volumoso uma vez ao dia e concentrado duas vezes ao dia; 1 V/3 C - volumoso uma vez ao dia e concentrado três vezes ao dia, ofertadas às categorias vacas e novilhas. A dieta foi composta de 60% de silagem de milho e 40% de concentrado com base na matéria seca (MS). O delineamento experimental foi inteiramente casualizado em arranjo fatorial 4 × 2 (frequências × categorias). Os dados foram submetidos à análise de variância e as médias, comparadas pelo teste t. A interação frequência de fornecimento e categoria animal foi significativa para as características tempo de ruminação e ócio, eficiência de ruminação da matéria seca e da fibra detergente neutro, número de bolos diário e tempo diário de mastigação. Em relação às vacas, as novilhas apresentaram maiores tempos de ócio e mastigação quando receberam a alimentação uma vez ao dia. A frequência de fornecimento da dieta não influenciou o tempo de consumo. As vacas apresentaram maior tempo consumindo alimento e taxa de ingestão em comparação às novilhas (4,38 vs 4,09 horas e 2,91 vs 2,35 kg de MS/hora de consumo, respectivamente). O aumento na frequência da alimentação estimula os animais a maior ingestão de alimento no momento do fornecimento.The present study was conducted with the objective of evaluating the influence of frequency of roughage and supplement supply and/or animal category on the ingestive behavior of cattle. Sixteen heifers and sixteen cows, with average initial age of 20 and 66 months and average initial weight of 338 and 432 kg, respectively, were used. Treatments were represented by the frequencies of roughage and concentrate supply: 2 R/C - roughage and concentrate two times per day; 1 R/C - roughage and concentrate one time per day; 1 R/2C - roughage one time per day and concentrate two times per day; 1 R/3 C - roughage one time per day and concentrate three times per day, offered to cows and heifers. Diet was composed of 60% maize silage and 40% concentrate, on a dry matter basis (DM). The complete randomized experimental design was used, with a 4 × 2 factorial arrangement (frequencies × category). The data were submitted to variance analysis and averages were compared by "t" test. The interaction between supply frequencies and animal category was significant for rumination and idle times, efficiencies of dry matter rumination and of neutral detergent fiber rumination, number of ruminated bolus and daily time of chew. Heifers showed longer idle periods and daily time of chew when compared with cows that received food once in a day. Duration of feed intake did not vary with frequencies. Cows showed longer period of feed intake and ingestive rate in relation to heifers (4.38 vs. 4.09 hours and 2.91 vs. 2.35 kg of DM/hour of intake, respectively). The increase in food frequency stimulated animals to intensify feed intake at the moment of supply

    Observation of photon-induced W<sup>+</sup>W<sup>−</sup> production in pp collisions at √s=13 TeV using the ATLAS detector

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    This letter reports the observation of photon-induced production of W-boson pairs, γγ→ WW. The analysis uses 139 fb-1 of LHC proton-proton collision data taken at √s=13 TeV recorded by the ATLAS experiment during the years 2015-2018. The measurement is performed selecting one electron and one muon, corresponding to the decay of the diboson system as WW→e±νμ∓ν final state. The background-only hypothesis is rejected with a significance of well above 5 standard deviations consistent with the expectation from Monte Carlo simulation. A cross section for the γγ→ WW process of 3.13±0.31(stat.)±0.28(syst.) fb is measured in a fiducial volume close to the acceptance of the detector, by requiring an electron and a muon of opposite signs with large dilepton transverse momentum and exactly zero additional charged particles. This is found to be in agreement with the Standard Model prediction

    Measurement of the total cross section and ρ -parameter from elastic scattering in pp collisions at √s=13 TeV with the ATLAS detector

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    In a special run of the LHC with β⋆=2.5 km, proton–proton elastic-scattering events were recorded at s√=13 TeV with an integrated luminosity of 340 μb−1 using the ALFA subdetector of ATLAS in 2016. The elastic cross section was measured differentially in the Mandelstam t variable in the range from −t=2.5⋅10−4 GeV2 to −t=0.46 GeV2 using 6.9 million elastic-scattering candidates. This paper presents measurements of the total cross section σtot, parameters of the nuclear slope, and the ρ-parameter defined as the ratio of the real part to the imaginary part of the elastic-scattering amplitude in the limit t→0. These parameters are determined from a fit to the differential elastic cross section using the optical theorem and different parameterizations of the t-dependence. The results for σtot and ρ are σtot(pp→X)=104.7±1.1 mb ,ρ=0.098±0.011. The uncertainty in σtot is dominated by the luminosity measurement, and in ρ by imperfect knowledge of the detector alignment and by modelling of the nuclear amplitude.publishedVersio

    Searches for lepton-flavour-violating decays of the Higgs boson in s=13\sqrt{s}=13 TeV pp\mathit{pp} collisions with the ATLAS detector

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    This Letter presents direct searches for lepton flavour violation in Higgs boson decays, H → eτ and H → μτ , performed with the ATLAS detector at the LHC. The searches are based on a data sample of proton–proton collisions at a centre-of-mass energy √s = 13 TeV, corresponding to an integrated luminosity of 36.1 fb−1. No significant excess is observed above the expected background from Standard Model processes. The observed (median expected) 95% confidence-level upper limits on the leptonflavour-violating branching ratios are 0.47% (0.34+0.13−0.10%) and 0.28% (0.37+0.14−0.10%) for H → eτ and H → μτ , respectively.publishedVersio

    Search for flavour-changing neutral currents in processes with one top quark and a photon using 81 fb⁻¹ of pp collisions at \sqrts = 13 TeV with the ATLAS experiment

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    A search for flavour-changing neutral current (FCNC) events via the coupling of a top quark, a photon, and an up or charm quark is presented using 81 fb−1 of proton–proton collision data taken at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. Events with a photon, an electron or muon, a b-tagged jet, and missing transverse momentum are selected. A neural network based on kinematic variables differentiates between events from signal and background processes. The data are consistent with the background-only hypothesis, and limits are set on the strength of the tqγ coupling in an effective field theory. These are also interpreted as 95% CL upper limits on the cross section for FCNC tγ production via a left-handed (right-handed) tuγ coupling of 36 fb (78 fb) and on the branching ratio for t→γu of 2.8×10−5 (6.1×10−5). In addition, they are interpreted as 95% CL upper limits on the cross section for FCNC tγ production via a left-handed (right-handed) tcγ coupling of 40 fb (33 fb) and on the branching ratio for t→γc of 22×10−5 (18×10−5). © 2019 The Author(s

    The ATLAS Fast TracKer system

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    The ATLAS Fast TracKer (FTK) was designed to provide full tracking for the ATLAS high-level trigger by using pattern recognition based on Associative Memory (AM) chips and fitting in high-speed field programmable gate arrays. The tracks found by the FTK are based on inputs from all modules of the pixel and silicon microstrip trackers. The as-built FTK system and components are described, as is the online software used to control them while running in the ATLAS data acquisition system. Also described is the simulation of the FTK hardware and the optimization of the AM pattern banks. An optimization for long-lived particles with large impact parameter values is included. A test of the FTK system with the data playback facility that allowed the FTK to be commissioned during the shutdown between Run 2 and Run 3 of the LHC is reported. The resulting tracks from part of the FTK system covering a limited η-ϕ region of the detector are compared with the output from the FTK simulation. It is shown that FTK performance is in good agreement with the simulation
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