1,206 research outputs found

    Lecithin addition to starter pig diets with and without added fat and whey

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    A total of 316 crossbred weanling pigs were used in two studies to evaluate the effect of the addition of edible-grade, unbleached soy lecithin on growth in starter pig diets with and without added fat and/or dried whey. Addition of fat to a corn-soybean meal diet improved (P\u3c.05) feed efficiency but addition of lecithin did not affect performance. When lecithin and fat were added in combination, average daily gain was less (P\u3c.05) than for diets without added fat. This may be due to a high level of undigestible fat having a limiting effect on intake and consequently decreasing gains. A low level of lecithin (1.5%) in diets without whey gave approximately the same response as a 4% fat diet without thus making lecithin a possible fat substitute should, it be economically feasible.; Swine Day, Manhattan, KS, November 15, 198

    Symmetry protection of topological order in one-dimensional quantum spin systems

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    We discuss the characterization and stability of the Haldane phase in integer spin chains on the basis of simple, physical arguments. We find that an odd-SS Haldane phase is a topologically non-trivial phase which is protected by any one of the following three global symmetries: (i) the dihedral group of π\pi-rotations about x,yx,y and zz axes; (ii) time-reversal symmetry Sx,y,z→−Sx,y,zS^{x,y,z} \rightarrow - S^{x,y,z}; (iii) link inversion symmetry (reflection about a bond center), consistently with previous results [Phys. Rev. B \textbf{81}, 064439 (2010)]. On the other hand, an even-SS Haldane phase is not topologically protected (i.e., it is indistinct from a trivial, site-factorizable phase). We show some numerical evidence that supports these claims, using concrete examples.Comment: 9 pages, 6 figures, extended version: several new examples and numerical results added. Journal reference adde

    Detection of Symmetry Protected Topological Phases in 1D

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    A topological phase is a phase of matter which cannot be characterized by a local order parameter. It has been shown that gapped phases in 1D systems can be completely characterized using tools related to projective representations of the symmetry groups. We show how to determine the matrices of these representations in a simple way in order to distinguish between different phases directly. From these matrices we also point out how to derive several different types of non-local order parameters for time reversal, inversion symmetry and Z2×Z2Z_2 \times Z_2 symmetry, as well as some more general cases (some of which have been obtained before by other methods). Using these concepts, the ordinary string order for the Haldane phase can be related to a selection rule that changes at the critical point. We furthermore point out an example of a more complicated internal symmetry for which the ordinary string order cannot be applied.Comment: 12 pages, 9 Figure

    Robust dynamic classes revealed by measuring the response function of a social system

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    We study the relaxation response of a social system after endogenous and exogenous bursts of activity using the time-series of daily views for nearly 5 million videos on YouTube. We find that most activity can be described accurately as a Poisson process. However, we also find hundreds of thousands of examples in which a burst of activity is followed by an ubiquitous power-law relaxation governing the timing of views. We find that these relaxation exponents cluster into three distinct classes, and allow for the classification of collective human dynamics. This is consistent with an epidemic model on a social network containing two ingredients: A power law distribution of waiting times between cause and action and an epidemic cascade of actions becoming the cause of future actions. This model is a conceptual extension of the fluctuation-dissipation theorem to social systems, and provides a unique framework for the investigation of timing in complex systems.Comment: 5 pages, 5 figures, submitted to PNA

    On confined fractional charges: a simple model

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    We address the question whether features known from quantum chromodynamics (QCD) can possibly also show up in solid-state physics. It is shown that spinless fermions of charge ee on a checkerboard lattice with nearest-neighbor repulsion provide for a simple model of confined fractional charges. After defining a proper vacuum the system supports excitations with charges ±e/2\pm e/2 attached to the ends of strings. There is a constant confining force acting between the fractional charges. It results from a reduction of vacuum fluctuations and a polarization of the vacuum in the vicinity of the connecting strings.Comment: 5 pages, 3 figure

    The neural basis of the bilateral distribution advantage

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    Letters can be matched by their physical identity (i.e., a–a: same/A–a: different) or by their name (both a–a and A–a: same). The latter, more demanding task has in previous experiments led to an advantage of bilateral over within-hemifield matches, which was not observed in the former. We have investigated the neural basis of this bilateral distribution advantage (BDA) in letter name matching with event-related fMRI. Unilateral, compared to bilateral, name matching led to increased activation in the contralateral fusiform and lateral occipital gyri. This increase went along with an ipsilateral increase of activation in homologous areas. Such a hemispheric resource sharing was not observed for letter shape matching. This pattern of activation shows that letter name matching induces hemispheric resource sharing in visual areas, which occurs when task demands in the hemisphere of input reach a critical level. Activation in anterior cingulate complex and posterior cingulate/retrosplenial cortex showed a task × visual field interaction with lower activation for bilateral than unilateral name matches but higher activation for bilateral than unilateral shape matches, which fits the interhemispheric transfer demands in these tasks

    Effects of Microbial Feed Additives on Performance of Starter and Growing-Finishing Pigs

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    Three trials were conducted to evaluate the effect of lactic acid-producing microbial feed additives (Probiotics) on performance of starting and growing-finishing pigs. Two commercially available probiotics, Probios (L. acidopbilus) and Feed-Mate 68 (Streptococcus faecium type Cernelle 68), were used. In the first of two starter trials, 192 crossbred pigs (initial weight 7 kg) were used in a 2 • 4 factorial arrangement of treatments, with Probios and antibiotics (ASP-250, lincomycin, tylosin) as the main effects

    Value of High Fiber Diets for Grand Swine

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    An experiment was conducted to determine the effect of roughages on the utilization of dietary nitrogen, energy and fiber by gravid swine. Water consumption, backfat depletion, pregnancy weight gain, and reproductive performance were used as response criteria

    Effect of regrouping unfamiliar pigs at weaning on immune function

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    Pigs weaned at 3 weeks of age and regrouped with unfamiliar individuals had a 4-fold increase in plasma cortisol when compared to pigs that remained in a litter group. However, cellular measures of immune function were not altered by regrouping.; Swine Day, Manhattan, KS, November 10, 198
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