2,646 research outputs found

    Dietary supplementation of essential oils in dairy cows: evidence for stimulatory effects on nutrient absorption

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    Results of recent in vitro experiments suggest that essential oils (EO) may not only influence ruminal fermentation but also modulate the absorption of cations like Na+, Ca2+ and NH4+ across ruminal epithelia of cattle and sheep through direct interaction with epithelial transport proteins, such as those of the transient receptor potential family. The aim of the current study was to examine this hypothesis by testing the effect of a blend of essential oils (BEO) on cation status and feed efficiency in lactating dairy cows. In the experiment, 72 dairy cows in mid-to-end lactation were divided into two groups of 36 animals each and fed the same mixed ration with or without addition of BEO in a 2×2 cross-over design. Feed intake, milk yield and composition, plasma and urine samples were monitored. Feeding BEO elevated milk yield, milk fat and protein yield as well as feed efficiency, whereas urea levels in plasma and milk decreased. In addition, plasma calcium levels increased significantly upon BEO supplementation, supporting the hypothesis that enhanced cation absorption might contribute to the beneficial effects of these EO

    Assessing the Effective Energy for Magnetic Forming Processes by Means of Measurements and Numerical Calculation

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    The efficiency of magnetic sheet metal forming processes is strongly depending on the facility s overall design. This mainly includes the geometric layout of forming tool, work piece and matrix but, however, will also expect the energy storage device being taken into consideration. Apart from field theoretic models the energy storage is describable by its terminal traits which the electric load - tool coil and work piece - is connected to. The paper presents a measuring method for the tool coil s terminal quantities, current i(t) and voltage u(t), which are used to provide the electric power p(t) being transferred to the load. Thus, it is possible to determine the entire energy which is dissipated by the work piece, provided that the coil s resistance is known. Besides the measurement, this approach is supported by numerical calculation intending to take a closer look at the inner losses of the work piece which are not accessible from measuring the system s terminal traits directly. Dividable into separate parts of the total energy, this information is applied to assess the forming process by means of the facility s energetic performance and to draw an overall energy balance

    Self-organized criticality in a rice-pile model

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    We present a new model for relaxations in piles of granular material. The relaxations are determined by a stochastic rule which models the effect of friction between the grains. We find power-law distributions for avalanche sizes and lifetimes characterized by the exponents τ=1.53±0.05\tau = 1.53 \pm 0.05 and y=1.84±0.05y = 1.84 \pm 0.05, respectively. For the discharge events, we find a characteristic size that scales with the system size as LμL^\mu, with μ=1.20±0.05\mu = 1.20 \pm 0.05. We also find that the frequency of the discharge events decrease with the system size as LμL^{-\mu'} with μ=1.20±0.05\mu' = 1.20 \pm 0.05.Comment: 4 pages, RevTex, multicol, epsf, rotate (sty files provided). To appear Phys. Rev. E Rapid Communication (Nov or Dec 96

    Word Processors with Line-Wrap: Cascading, Self-Organized Criticality, Random Walks, Diffusion, Predictability

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    We examine the line-wrap feature of text processors and show that adding characters to previously formatted lines leads to the cascading of words to subsequent lines and forms a state of self-organized criticality. We show the connection to one-dimensional random walks and diffusion problems, and we examine the predictability of catastrophic cascades.Comment: 6 pages, LaTeX with RevTeX package, 4 postscript figures appende

    Universality classes for rice-pile models

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    We investigate sandpile models where the updating of unstable columns is done according to a stochastic rule. We examine the effect of introducing nonlocal relaxation mechanisms. We find that the models self-organize into critical states that belong to three different universality classes. The models with local relaxation rules belong to a known universality class that is characterized by an avalanche exponent τ1.55\tau \approx 1.55, whereas the models with nonlocal relaxation rules belong to new universality classes characterized by exponents τ1.35\tau \approx 1.35 and τ1.63\tau \approx 1.63. We discuss the values of the exponents in terms of scaling relations and a mapping of the sandpile models to interface models.Comment: 4 pages, including 3 figure

    Anomalous Transport in Conical Granular Piles

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    Experiments on 2+1-dimensional piles of elongated particles are performed. Comparison with previous experiments in 1+1 dimensions shows that the addition of one extra dimension to the dynamics changes completely the avalanche properties, appearing a characteristic avalanche size. Nevertheless, the time single grains need to cross the whole pile varies smoothly between several orders of magnitude, from a few seconds to more than 100 hours. This behavior is described by a power-law distribution, signaling the existence of scale invariance in the transport process.Comment: Accepted in PR

    A Method to Estimate the Boson Mass and to Optimise Sensitivity to Helicity Correlations of tau+tau- Final States

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    In proton-proton collisions at LHC energies, Z and low mass Higgs bosons would be produced with high and predominantly longitudinal boost with respect to the beam axis. This note describes a new analysis tool devised to handle this situation in cases when such bosons decay to a pair of tau-leptons. The tool reconstructs the rest frame of the tau+tau- pair by finding the boost that minimises the acollinearity between the visible tau decay products. In most cases this gives a reasonable approximation to the rest frame of the decaying boson. It is shown how the reconstructed rest frame allows for a new method of mass estimation. Also a considerable gain in sensitivity to helicity correlations is obtained by analysing the tau-jets in the reconstructed frame instead of using the laboratory momenta and energies, particularly when both tau-leptons decay hadronically.Comment: 13 pages, method extended with 3D boost finde

    Multifractal properties of power-law time sequences; application to ricepiles

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    We study the properties of time sequences extracted from a self-organized critical system, within the framework of the mathematical multifractal analysis. To this end, we propose a fixed-mass algorithm, well suited to deal with highly inhomogeneous one dimensional multifractal measures. We find that the fixed mass (dual) spectrum of generalized dimensions depends on both the system size L and the length N of the sequence considered, being however stable when these two parameters are kept fixed. A finite-size scaling relation is proposed, allowing us to define a renormalized spectrum, independent of size effects.We interpret our results as an evidence of extremely long-range correlations induced in the sequence by the criticality of the systemComment: 12 pages, RevTex, includes 9 PS figures, Phys. Rev. E (in press
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