4,265 research outputs found

    System Fitness of Grazeable Forages for Large Herds in Automatic Milking Systems

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    Automatic milking rotary (AMR) systems have the capacity to milk 800 cows. To maintain a pasture-based system whereby \u3e 50% of the total diet is pasture (Garcia and Fulkerson, 2005), large herds milked by AMR will be required to walk significant distances. Walking distances of greater than 1-km are associated with an increased incidence of undesirably long milking intervals and reduced milk yield (Lyons N, unpubl. data). The aim of this study was to investigate the total land area required and associated walking distance for large automatic milking system (AMS) herds when incorporating complementary forage rotations (CFR; Garcia et al., 2008) into the system

    Grazing Behaviour of Dairy Cows When Grazing Forage Rape in a Pasture-Based Automatic Milking System

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    Forage rape (Brassica napus L.) is a high producing, high nutritive value forage that has been successfully introduced as a grazable forage in conventional, intensified pasture-based dairy systems to fill autumn-winter feed gaps (Garcia et al. 2008). However, incorporation of forage rape as a grazing forage option for automatic milking systems (AMS), in which cows enter and exit grazing areas voluntarily, has not been investigated yet. We conducted an observational study to investigate the suitability of using forage rape in AMS and gain understanding of cow’s foraging behaviour when grazing this forage. The outcomes of this piece of work will help to determine management guidelines regarding incorporation of the crop into voluntary cow traffic systems

    Gaps and Variability in Pasture Utilisation in Australian Pasture-Based Dairy Systems

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    We used commercial farm data from 4 states of Australia and 9 subsets of data from 4 whole farm system studies conducted in Australia and New Zealand to: (1) explore the relationship between pasture utilisation and farm profitability; (2) identify gaps and causes of both between and within-farm variability in pasture utilisation; and (3) discuss possibilities to reduce these gaps through the application of technology-based solutions. Results confirm that the amount of pasture utilised per ha is a key driver of profitability of Australian pasture-based systems. In spite of this, the gap between potential (research) and commercial reality is huge. Data from whole farm system studies in which the same grazing management rules were applied show a relatively large variability in between-paddock, within-farm (i.e. system study in this case) pasture utilisation. The level of variability among datasets was similar, but was higher for systems associated with more variation in water availability compared to fully irrigated systems or studies conducted in high rainfall areas. Factors that can explain within farm variability include differential management of inputs and grazing, even when the ‘same’ management rules are applied. Given the demonstrated importance of pasture utilisation in profitability of the dairy farms, the key challenge for Australian dairy farmers is to seriously reduce variability in pasture utilisation and pasture wastage. The advancements of automation in agriculture provide new frontiers to assist farmers in reducing variability and gaps in pasture utilisation

    Increasing Feed Conversion Efficiency in Automatic Milking Systems: The Impact of Grain-Based Concentrate Allocation and Kikuyu (\u3cem\u3ePennisetum clandestinum\u3c/em\u3e) Pasture State on Milk Production

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    Pasture is typically offered to dairy cows in three allocations in pasture-based automatic milking systems (AMS). However, due to voluntary cow movement and distribution of milkings, some dairy cows access fresh pasture and other cows access depleted (stale) pasture. The first cows moving to an allocation of fresh pasture are offered ad-libitum, high quality pasture as opposed to cows arriving to the same allocation during the middle or end of the day accessing poorer quality, high fibre (neutral detergent fibre, NDF) pasture. In addition, grain-based concentrate (GBC) is allocated independently to this pasture state. The ability to increase feed conversion efficiency and AMS herd milk production by targetedGBC supplementation to cows accessing differing pasture states is unknown. Therefore, the aim of the current experiment was to determine the impact of pasture state and GBC allocation on dairy cow milk production

    Increasing Feed Conversion Efficiency in Automatic Milking Systems: The Impact of Grain-Based Concentrate Allocation and Kikuyu (\u3cem\u3ePennisetum clandestinum\u3c/em\u3e) Pasture State on Kikuyu Pasture Digestibility

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    Automatic milking system (AMS) farms, rely upon voluntary cow traffic (the voluntary movement of cattle around a farm) for milk harvesting and feed consumption. Dairy cows on a pasture-based AMS farm typically move from depleted to fresh allocations of pasture in small groups, or individually, at differing times. The first cows moving to an allocation of fresh pasture get access to rapidly fermentable, ad libitum, high quality pasture in contrast to those cows accessing the same allocation towards the end of the access period. At the same time, grain-based concentrate (GBC) is allocated independent of the pasture state that cows access. Inclusion of a high level of GBC in the diet with high or low nutritive value forage, or variable states of forage, may create dramatic variations in rumen fluid pH, which may induce subacute ruminal acidosis (Bramley 2004), reduce feed conversion efficiency and negatively impact animal health. The aim of the current study was to determine the impact of pasture state and GBC allocation on the digestibility of kikuyu pasture

    Why are Prices Sticky? Evidence from Business Survey Data

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    This paper offers new insights on the price setting behaviour of German retail firms using a novel dataset that consists of a large panel of monthly business surveys from 1991-2006. The firm-level data allows matching changes in firms' prices to several other firm-characteristics. Moreover, information on price expectations allow analyzing the determinants of price updating. Using univariate and bivariate ordered probit specifications, empirical menu cost models are estimated relating the probability of price adjustment and price updating, respectively, to both time- and state- dependent variables. First, results suggest an important role for state-dependence; changes in the macroeconomic and institutional environment as well as firm-specific factors are significantly related to the timing of price adjustment. These findings imply that price setting models should endogenize the timing of price adjustment in order to generate realistic predictions concerning the transmission of monetary policy. Second, an analysis of price expectations yields similar results providing evidence in favour of state-dependent sticky plan models. Third, intermediate input cost changes are among the most important determinants of price adjustment suggesting that pricing models should explicitly incorporate price setting at different production stages. However, the results show that adjustment to input cost changes takes time indicating "additional stickiness" at the last stage of processing

    CD1a expression by Barrett's metaplasia of gastric type may help to predict its evolution towards cancer

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    As emerging in the recent literature, CD1a has been regarded as a molecule whose expression may reflect tumour evolution. The aim of the present work was to investigate the expression of CD1a in a series of Barrett's metaplasia (BM), gastric type (GTBM), with and without follow-up, in order to analyse whether its expression may help to diagnose this disease and to address the outcome. Indeed, GTBM may be confused sometimes with islets of ectopic gastric mucosa and its evolution towards dysplasia (Dy) or carcinoma (Ca) could not be foreseen. We showed a significant higher expression of CD1a in GTBM than in both Dy and Ca; nevertheless, the number of positive GTBM was significantly lower in the group of cases that at follow-up underwent Dy or Ca. Our data address that CD1a may be a novel biomarker for BM and that its expression may help to predict the prognosis of this pathology

    Spectroscopic observations of the candidate sgB[e]/X-ray binary CI Cam

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    We present a compilation of spectroscopic observations of the sgB[e] star CI Cam. This includes data from before, during, and after its 1998 outburst. The object shows a rich emission line spectrum originating from circumstellar material, rendering it difficult to determine the nature of either star involved or the cause of the outburst. We collate pre-outburst data to determine the state of the system before this occurred and provide a baseline for comparison with later data. During the outburst all lines become stronger, and hydrogen and helium lines become significantly broader and asymmetric. After the outburst, spectral changes persist for at least three years, with FeII and [NII] lines still a factor of ~2 above the pre-outburst level and HeI, HeII, and NII lines suppressed by a factor of 2-10. We find that the spectral properties of CI Cam are similar to other sgB[e] stars and therefore suggest that the geometry of the circumstellar material is similar to that proposed for the other objects: a two component outflow, with a fast, hot, rarefied polar wind indistinguishable from that of a normal supergiant and a dense, cooler equatorial outflow with a much lower velocity. We suggest that CI Cam is among the hotter members of the class and is viewed nearly pole-on. The nature of the compact object and the mechanism for the outburst remain uncertain, although it is likely that the compact object is a black hole or neutron star, and that the outburst was precipitated by its passage through the equatorial material. We suggest that this prompted a burst of supercritical accretion resulting in ejection of much of the material, which was later seen as an expanding radio remnant. [Abbreviated]Comment: 25 pages including figures. Accepted for publication in A&

    The calibration system for the photomultiplier array of the SNO+ experiment

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    A light injection system using LEDs and optical fibres was designed for the calibration and monitoring of the photomultiplier array of the SNO+ experiment at SNOLAB. Large volume, non-segmented, low-background detectors for rare event physics, such as the multi-purpose SNO+ experiment, need a calibration system that allow an accurate and regular measurement of the performance parameters of their photomultiplier arrays, while minimising the risk of radioactivity ingress. The design implemented for SNO+ uses a set of optical fibres to inject light pulses from external LEDs into the detector. The design, fabrication and installation of this light injection system, as well as the first commissioning tests, are described in this paper. Monte Carlo simulations were compared with the commissioning test results, confirming that the system meets the performance requirements

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
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