1,296 research outputs found

    Scoping a public health impact assessment of aquaculture with particular reference to tilapia in the UK

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    Background. The paper explores shaping public health impact assessment tools for tilapia, a novel emergent aquaculture sector in the UK. This Research Council’s UK Rural Economy and Land Use project embraces technical, public health, and marketing perspectives scoping tools to assess possible impacts of the activity. Globally, aquaculture produced over 65 million tonnes of food in 2008 and will grow significantly requiring apposite global public health impact assessment tools.<p></p> Methods. Quantitative and qualitative methods incorporated data from a tridisciplinary literature. Holistic tools scoped tilapia farming impact assessments. Laboratory-based tilapia production generated data on impacts in UK and Thailand along with 11 UK focus groups involving 90 consumers, 30 interviews and site visits, 9 visits to UK tilapia growers and 2 in The Netherlands.<p></p> Results. The feasibility, challenges, strengths, and weaknesses of creating a tilapia Public Health Impact Assessment are analysed. Occupational and environmental health benefits and risks attached to tilapia production were identified.<p></p> Conclusions. Scoping public health impacts of tilapia production is possible at different levels and forms for producers, retailers, consumers, civil society and governmental bodies that may contribute to complex and interrelated public health assessments of aquaculture projects. Our assessment framework constitutes an innovatory perspective in the field

    Optimal Concentration of Information Content For Log-Concave Densities

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    An elementary proof is provided of sharp bounds for the varentropy of random vectors with log-concave densities, as well as for deviations of the information content from its mean. These bounds significantly improve on the bounds obtained by Bobkov and Madiman ({\it Ann. Probab.}, 39(4):1528--1543, 2011).Comment: 15 pages. Changes in v2: Remark 2.5 (due to C. Saroglou) added with more general sufficient conditions for equality in Theorem 2.3. Also some minor corrections and added reference

    Effect of feeding three lysine to energy diets on growth, body composition and age at puberty in replacement gilts

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    This study evaluated the effect of diets differing in standard ileal digestible (SID) lysine on lysine intake, growth rate, body composition and age at puberty on maternal line gilts. Crossbred Large White×Landrace gilts (n =641) were fed corn-soybean diets differing in SID lysine concentration (%, g SID lysine:Mcal ME); diets were not isocaloric. Gilts received three grower, finisher diet combinations: low (0.68% lysine grower, 0.52% lysine finisher), medium (0.79% lysine grower, 0.60% lysine finisher) or high (0.90% lysine grower, 0.68% lysine finisher). Grower diets were fed from 100 until 142 days of age, and finisher diets were fed until they reached 220 days of age. Body weight (BW), backfat thickness (BF), and loin depth (LD) were recorded every 28 days. From 160–220 days of age, gilts were exposed daily to vasectomized boars and observed for behavioral estrus. Gilts fed the low lysine diet had lower average daily gain and BW (P \u3c 0.05), but not fat depth:LD ratio. The percentage of gilts that displayed natural estrus by 220 days of age was low but not different among dietary treatments (low 27.7%, medium 31.0% and high 37.7%, respectively; P=0.1201). Gilts fed the high and medium diets reached puberty 10 and 6 days earlier, however, than gilts fed the low lysine diet (P \u3c 0.05). The rate of puberty attainment may have been less because all gilts contracted porcine epidemic diarrhea (PEDv) just as boar exposure was to begin for the first group of gilts. Results from the present study indicate that growth rate and age at puberty can be altered by ad libitum fed diets that differ in SID lysine concentration

    From QCD lattice calculations to the equation of state of quark matter

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    We describe two-flavor QCD lattice data for the pressure at finite temperature and zero chemical potential within a quasiparticle model. Relying only on thermodynamic selfconsistency, the model is extended to nonzero chemical potential. The results agree with lattice calculations in the region of small chemical potential.Comment: 5 eps figure

    An update on the Hirsch conjecture

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    The Hirsch conjecture was posed in 1957 in a letter from Warren M. Hirsch to George Dantzig. It states that the graph of a d-dimensional polytope with n facets cannot have diameter greater than n - d. Despite being one of the most fundamental, basic and old problems in polytope theory, what we know is quite scarce. Most notably, no polynomial upper bound is known for the diameters that are conjectured to be linear. In contrast, very few polytopes are known where the bound ndn-d is attained. This paper collects known results and remarks both on the positive and on the negative side of the conjecture. Some proofs are included, but only those that we hope are accessible to a general mathematical audience without introducing too many technicalities.Comment: 28 pages, 6 figures. Many proofs have been taken out from version 2 and put into the appendix arXiv:0912.423

    Band structure and reflectance for a nonlinear one-dimensional photonic crystal

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    We consider a model for a one-dimensional photonic crystal formed by a succession of Kerr-type equidistant spaceless interfaces immersed in a linear medium. We calculate the band structure and reflectance of this structure as a function of the incident wave intensity, and find two main behaviors: the appearance of prohibited bands, and the separation and narrowing of these bands. A system with these features is obtained by alternating very thin slabs of a soft matter material with thicker solid films, which can be used to design a device to control light propagation for specific wavelength intervals and light intensities.Comment: 6 pages, 6 figure

    A Nonlinear Force-Free Magnetic Field Approximation Suitable for Fast Forward-Fitting to Coronal Loops. I. Theory

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    We derive an analytical approximation of nonlinear force-free magnetic field solutions (NLFFF) that can efficiently be used for fast forward-fitting to solar magnetic data, constrained either by observed line-of-sight magnetograms and stereoscopically triangulated coronal loops, or by 3D vector-magnetograph data. The derived NLFFF solutions provide the magnetic field components Bx(x)B_x({\bf x}), By(x)B_y({\bf x}), Bz(x)B_z({\bf x}), the force-free parameter α(x)\alpha({\bf x}), the electric current density j(x){\bf j}({\bf x}), and are accurate to second-order (of the nonlinear force-free α\alpha-parameter). The explicit expressions of a force-free field can easily be applied to modeling or forward-fitting of many coronal phenomena.Comment: Solar Physics (in press), 26 pages, 11 figure

    Numerical Portrait of a Relativistic BCS Gapped Superfluid

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    We present results of numerical simulations of the 3+1 dimensional Nambu - Jona-Lasinio (NJL) model with a non-zero baryon density enforced via the introduction of a chemical potential mu not equal to 0. The triviality of the model with a number of dimensions d>=4 is dealt with by fitting low energy constants, calculated analytically in the large number of colors (Hartree) limit, to phenomenological values. Non-perturbative measurements of local order parameters for superfluidity and their related susceptibilities show that, in contrast to the 2+1 dimensional model, the ground-state at high chemical potential and low temperature is that of a traditional BCS superfluid. This conclusion is supported by the direct observation of a gap in the dispersion relation for 0.5<=(mu a)<=0.85, which at (mu a)=0.8 is found to be roughly 15% the size of the vacuum fermion mass. We also present results of an initial investigation of the stability of the BCS phase against thermal fluctuations. Finally, we discuss the effect of splitting the Fermi surfaces of the pairing partners by the introduction of a non-zero isospin chemical potential.Comment: 41 pages, 19 figures, uses axodraw.sty, v2: minor typographical correction
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