1,283 research outputs found

    Benefits of a commercial solid-state fermentation (SSF) product on growth performance, feed efficiency and gut morphology of juvenile Nile tilapia (Oreochromis niloticus) fed different UK lupin meal cultivars

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    A nutritional investigation was conducted to determine whether growth performance, feed efficiency and midgut morphology of Nile tilapia is affected by United Kingdom cultivars of Yellow Lupin (Control, Y) (YLC) or Blue Lupin (Control, B) (BLC) inclusions compared to the addition of a commercial solid-state fermentation product (SSF) in separate dietary treatments for both lupin cultivars (YLS and BLS). After 49 days of feeding, tilapia receiving SSF supplemented diets (YLS & BLS) exhibited significantly greater weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER) and condition factor (K) compared to YLC or BLC without solid state fermentation. SSF inclusion exhibited significantly improving of enterocyte height within both the first and second half of the experiment (P .05); although a potential response over time was apparent in the YLS group. Enterocyte microvilli were significantly wider in fish fed YLC diets (P < .05), whilst they were significantly longer in the BLC control compared to the YLC control (P < .05). Microvilli lengths of fish fed YLS were comparable to those receiving BLC diets and close to being significantly longer than those fed YLC alone (P = .06). Overall, BLC appeared to perform superiorly to YLC; whilst SSF inclusion promoted some desirable production parameters, seemingly most effectively in the YLC diet

    Dietary nucleotides enhance growth performance, feed efficiency and intestinal functional topography in European Seabass ( Dicentrarchus labrax )

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    Nucleotides, nucleosides and nucleic acids (NU) have many critical functions in supporting life and increasing evidence suggests that exogenous supply can benefit the health of mammals and fish. For these reasons, a 6‐week feeding trial was conducted on juvenile European seabass (Dicentrarchus labrax) with diets containing 0%, 0.15% and 0.3% inclusion of a NU mixture (Laltide¼) derived from the yeast Saccharomyces cerevisiae. At the end of the study no significant differences were found in fish performance, although a tendency towards better performance was indicated in fish fed the Nu0.3 diet. In relation to histological assessment, a significantly greater perimeter ratio; internal to outer (IP/OP) was observed in the posterior intestine of fish fed supplemental NU. Microvilli heights in the posterior intestine were also shown to be significantly promoted in fish fed NU diets (p 0.05). Overall, this study indicates that orally administered NU may be effective promoters of gut functional topography with marginal associated improvements to fish performance. Nonetheless, longer exposure and/or commercial scale application, and in diets that were challenging in use of high inclusion levels of plant by‐products would potentially amplify improvements in production characteristics, in turn benefiting fish culturists

    Interactions, Distribution of Pinning Energies, and Transport in the Bose Glass Phase of Vortices in Superconductors

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    We study the ground state and low energy excitations of vortices pinned to columnar defects in superconductors, taking into account the long--range interaction between the fluxons. We consider the ``underfilled'' situation in the Bose glass phase, where each flux line is attached to one of the defects, while some pins remain unoccupied. By exploiting an analogy with disordered semiconductors, we calculate the spatial configurations in the ground state, as well as the distribution of pinning energies, using a zero--temperature Monte Carlo algorithm minimizing the total energy with respect to all possible one--vortex transfers. Intervortex repulsion leads to strong correlations whenever the London penetration depth exceeds the fluxon spacing. A pronounced peak appears in the static structure factor S(q)S(q) for low filling fractions f≀0.3f \leq 0.3. Interactions lead to a broad Coulomb gap in the distribution of pinning energies g(Ï”)g(\epsilon) near the chemical potential ÎŒ\mu, separating the occupied and empty pins. The vanishing of g(Ï”)g(\epsilon) at ÎŒ\mu leads to a considerable reduction of variable--range hopping vortex transport by correlated flux line pinning.Comment: 16 pages (twocolumn), revtex, 16 figures not appended, please contact [email protected]

    On The Problem of Particle Production in c=1 Matrix Model

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    We reconsider and analyze in detail the problem of particle production in the time dependent background of c=1c=1 matrix model where the Fermi sea drains away at late time. In addition to the moving mirror method, which has already been discussed in hep-th/0403169 and hep-th/0403275, we describe yet another method of computing the Bogolubov coefficients which gives the same result. We emphasize that these Bogolubov coefficients are approximately correct for small value of the deformation parameter. We also study the time evolution of the collective field theory stress-tensor with a special point-splitting regularization. Our computations go beyond the approximation of the previous treatments and are valid at large coordinate distances from the boundary at a finite time and up-to a finite coordinate distance from the boundary at late time. In this region of validity our regularization produces a certain singular term that is precisely canceled by the collective field theory counter term in the present background. The energy and momentum densities fall off exponentially at large distance from the boundary to the values corresponding to the static background. This clearly shows that the radiated energy reaches the asymptotic region signaling the space-time decay.Comment: 37 pages, 5 figures. Section 6 is modified to clarify main accomplishments of the paper including a discussion comparing stress-tensor analysis with those preexisted in literature. Other modifications include minor changes in the text and addition of one reference. Version accepted for publication in JHE

    Staggered versus overlap fermions: a study in the Schwinger model with Nf=0,1,2N_f=0,1,2

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    We study the scalar condensate and the topological susceptibility for a continuous range of quark masses in the Schwinger model with Nf=0,1,2N_f=0,1,2 dynamical flavors, using both the overlap and the staggered discretization. At finite lattice spacing the differences between the two formulations become rather dramatic near the chiral limit, but they get severely reduced, at the coupling considered, after a few smearing steps.Comment: 15 pages, 7 figures, v2: 1 ref corrected, minor change

    Static quantities of the W boson in the SU_L(3) X U_X(1) model with right-handed neutrinos

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    The static electromagnetic properties of the WW boson, ΔÎș\Delta \kappa and ΔQ\Delta Q, are calculated in the SU_L(3)} \times U_X(1) model with right-handed neutrinos. The new contributions from this model arise from the gauge and scalar sectors. In the gauge sector there is a new contribution from a complex neutral gauge boson Y0Y^0 and a singly-charged gauge boson Y±Y^\pm. The mass of these gauge bosons, called bileptons, is expected to be in the range of a few hundreds of GeV according to the current bounds from experimental data. If the bilepton masses are of the order of 200 GeV, the size of their contribution is similar to that obtained in other weakly coupled theories. However the contributions to both ΔQ\Delta Q and ΔÎș\Delta \kappa are negligible for very heavy or degenerate bileptons. As for the scalar sector, an scenario is examined in which the contribution to the WW form factors is identical to that of a two-Higgs-doublet model. It is found that this sector would not give large corrections to ΔÎș\Delta \kappa and ΔQ\Delta Q.Comment: New material included. Final version to apppear in Physical Review

    Neutrino Masses with "Zero Sum" Condition: mΜ1+mΜ2+mΜ3=0m_{\nu_1} + m_{\nu_2} + m_{\nu_3} = 0

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    It is well known that the neutrino mass matrix contains more parameters than experimentalists can hope to measure in the foreseeable future even if we impose CP invariance. Thus, various authors have proposed ansatzes to restrict the form of the neutrino mass matrix further. Here we propose that mÎœ1+mÎœ2+mÎœ3=0m_{\nu_1} + m_{\nu_2} + m_{\nu_3} = 0; this ``zero sum'' condition can occur in certain class of models, such as models whose neutrino mass matrix can be expressed as commutator of two matrices. With this condition, the absolute neutrino mass can be obtained in terms of the mass-squared differences. When combined with the accumulated experimental data this condition predicts two types of mass hierarchies, with one of them characterized by mÎœ3≈−2mÎœ1≈−2mÎœ2≈0.063m_{\nu_3} \approx -2m_{\nu_1} \approx -2 m_{\nu_2} \approx 0.063 eV, and the other by mÎœ1≈−mÎœ2≈0.054m_{\nu_1} \approx -m_{\nu_2} \approx 0.054 eV and mÎœ3≈0.0064m_{\nu_3} \approx 0.0064 eV. The mass ranges predicted is just below the cosmological upper bound of 0.23 eV from recent WMAP data and can be probed in the near future. We also point out some implications for direct laboratory measurement of neutrino masses, and the neutrino mass matrix.Comment: Latex 12 pages. No figures. New references adde

    On the vanishing electron-mass limit in plasma hydrodynamics in unbounded media

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    We consider the zero-electron-mass limit for the Navier-Stokes-Poisson system in unbounded spatial domains. Assuming smallness of the viscosity coefficient and ill-prepared initial data, we show that the asymptotic limit is represented by the incompressible Navier-Stokes system, with a Brinkman damping, in the case when viscosity is proportional to the electron-mass, and by the incompressible Euler system provided the viscosity is dominated by the electron mass. The proof is based on the RAGE theorem and dispersive estimates for acoustic waves, and on the concept of suitable weak solutions for the compressible Navier-Stokes system

    The Concise Guide to Pharmacology 2015/16: Transporters

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    The Concise Guide to PHARMACOLOGY 2015/16 provides concise overviews of the key properties of over 1750 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.13355/full. G protein-coupled receptors are one of the eight major pharmacological targets into which the Guide is divided, with the others being: G protein-coupled receptors, ligand-gated ion channels, voltage-gated ion channels, other ion channels, nuclear hormone receptors, catalytic receptors and transporters. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. The Concise Guide is published in landscape format in order to facilitate comparison of related targets. It is a condensed version of material contemporary to late 2015, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in the previous Guides to Receptors & Channels and the Concise Guide to PHARMACOLOGY 2013/14. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and GRAC and provides a permanent, citable, point-in-time record that will survive database update

    Complex Langevin: Etiology and Diagnostics of its Main Problem

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    The complex Langevin method is a leading candidate for solving the so-called sign problem occurring in various physical situations. Its most vexing problem is that in some cases it produces `convergence to the wrong limit'. In the first part of the paper we go through the formal justification of the method, identify points at which it may fail and identify a necessary and sufficient criterion for correctness. This criterion would, however, require checking infinitely many identities, and therefore is somewhat academic. We propose instead a truncation to the check of a few identities; this still gives a necessary criterion, but a priori it is not clear whether it remains sufficient. In the second part we carry out a detailed study of two toy models: first we identify the reasons why in some cases the method fails, second we test the efficiency of the truncated criterion and find that it works perfectly at least in the toy models studied.Comment: 39 pages, 15 figures; typos corrected and reference adde
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