792 research outputs found

    Merino ewes that are genetically fatter lose less weight when nutrition is restricted

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    Ewes that lose less weight when there is a shortage of paddock feed are potentially more profitable because they require less supplementary feeding or can be grazed at higher stocking rates during autumn/winter (Young et al. 2011). Adams et al. (2006) have shown that sheep genotypes which lose more weight when underfed have lower metabolic reserves including fat. This paper tested the hypothesis that selection for increased fatness would reduce the rate of liveweight loss in adult Merino ewes when nutrition was restricted

    Whole-body fatness is a good predictor of phenotypic feed and liveweight efficiency in adult Merino ewes fed a poor-quality diet

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    Weight loss due to poor nutrition in adult ewes over summer-autumn is economically expensive due to immediate costs such as feed and labour but also due to ongoing costs to reproductive success and ewe health. We predicted that adult Merino ewes with a higher proportion of fat would be more efficient, both through lower intake and reduced weight loss. Four-year-old Merino ewes (n ≤ 64) were held in single pens and fed a chaff-based diet either ad libitum, with the aim of achieving liveweight maintenance, or a restricted amount to achieve liveweight loss of 100 g/day. Liveweight change and feed intake were measured, and residual liveweight change and residual feed intake were used to indicate efficiency. There was a difference of 2 MJ of metabolisable energy per day between the most efficient and least efficient ewes for residual feed intake, and a difference of 90 g per day between the most efficient and least efficient ewes for residual liveweight change. There was a significant association between blood plasma concentrations of leptin and both liveweight and feed efficiency, so that ewes with high concentrations of leptin had a lower daily intake, and/or lost less weight than did those with low concentrations of leptin. Managing adult Merino ewes to maximise fat-tissue accretion during spring via genetics and/or nutritional management could be a useful strategy to reduce feed requirements during summer-autumn because the ewes will be more efficient and have larger fat reserves to lose before achieving a lower critical limit

    Nonresonant Contributions in B->rho pi Decay

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    We consider nonresonant contributions in the Dalitz plot analysis of B->rho pi->pi^+ pi^- pi^0 decay and their potential impact on the extraction of the CKM parameter alpha. In particular, we examine the role of the heavy mesons B^* and B_0, via the process B->pi (B^*, B_0)->pi^+ pi^- pi^0, and their interference with resonant contributions in the rho-mass region. We discuss the inherent uncertainties and suggest that the effects may be substantially smaller than previously indicated.Comment: 15 pages, 3 figures; minor changes, version to appear in Phys. Rev.

    On observability of Renyi's entropy

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    Despite recent claims we argue that Renyi's entropy is an observable quantity. It is shown that, contrary to popular belief, the reported domain of instability for Renyi entropies has zero measure (Bhattacharyya measure). In addition, we show the instabilities can be easily emended by introducing a coarse graining into an actual measurement. We also clear up doubts regarding the observability of Renyi's entropy in (multi--)fractal systems and in systems with absolutely continuous PDF's.Comment: 18 pages, 1 EPS figure, REVTeX, minor changes, accepted to Phys. Rev.

    Evading the CKM Hierarchy: Intrinsic Charm in B Decays

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    We show that the presence of intrinsic charm in the hadrons' light-cone wave functions, even at a few percent level, provides new, competitive decay mechanisms for B decays which are nominally CKM-suppressed. For example, the weak decays of the B-meson to two-body exclusive states consisting of strange plus light hadrons, such as B\to\pi K, are expected to be dominated by penguin contributions since the tree-level b\to s u\bar u decay is CKM suppressed. However, higher Fock states in the B wave function containing charm quark pairs can mediate the decay via a CKM-favored b\to s c\bar c tree-level transition. Such intrinsic charm contributions can be phenomenologically significant. Since they mimic the amplitude structure of ``charming'' penguin contributions, charming penguins need not be penguins at all.Comment: 28 pages, 6 figures, published version. References added, minor change

    Metacognition and lifelong e-learning: a contextual and cyclical process

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    Metacognition is arguably an important conceptualisation within the area of lifelong e- learning, with many theorists and practitioners claiming that it enhances the learning process. However, the lifelong, cyclical and flexible aspects of 'before', 'during' and 'after' metacognitions within lifelong e-learning (inclusive of whether an 'input' necessarily leads to a completed 'output') seem marginal within current areas of practical and theoretical debate. This article analyses Reeves's (1997) model of web-based learning in the context of the ADAPT project; a study of lifelong learners based in small and medium sized enterprises. The article focuses upon an analysis of this model's view of metacognition, and in the light of the project findings and literature review, aims to put forward an extended and expanded version of the model with reference to lifelong e-learnin

    Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

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    Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
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