111 research outputs found

    Genetic parameters for casein and urea content in the Italian Brown Swiss dairy cattle

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    A total of 137,753 test day records of 20,745 Italian Brown Swiss dairy cows from 26 provinces of Italy were used to estimate heritability for casein and urea content in milk and their genetic correlations with other production traits and milk somatic cell score. Milk component values were obtained by Fourier Transformed Infrared (IR) Spectroscopy from milk samples collected during national routine recording and were analysed using test day repeatability animal models. Fixed effects included 1,001 levels of herd-test date, 15 classes of days in milk, and 13 classes of age at calving within parity. The variation among cows was large for most of the traits. The heritability value for casein content was 0.31, as for protein content, and genetic and phenotypic correlations between these two traits were large (0.99 and 0.97 respectively). Milk urea content had a heritability of 0.17 and a positive genetic relationship with fat (0.12), null with protein (0.03) and casein (0.002) content and a negative genetic correlation with milk yield (-0.17) suggesting that the genetic improvement for milk urea content would be possible, but genetic gain would be affected by other traits included as selection criteria in the economic index and by their relative economic emphasis

    Phonon anomalies due to strong electronic correlations in layered organic metals

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    We show how the coupling between the phonons and electrons in a strongly correlated metal can result in phonon frequencies which have a non-monotonic temperature dependence. Dynamical mean-field theory is used to study the Hubbard-Holstein model that describes the \kappa-(BEDT-TTF)_2 X family of superconducting molecular crystals. The crossover with increasing temperature from a Fermi liquid to a bad metal produces phonon anomalies that are consistent with recent Raman scattering and acoustic experiments.Comment: 6 pages, 3 eps figure

    Nonlinear equation for anomalous diffusion: unified power-law and stretched exponential exact solution

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    The nonlinear diffusion equation ρt=DΔ~ρν\frac{\partial \rho}{\partial t}=D \tilde{\Delta} \rho^\nu is analyzed here, where Δ~1rd1rrd1θr\tilde{\Delta}\equiv \frac{1}{r^{d-1}}\frac{\partial}{\partial r} r^{d-1-\theta} \frac{\partial}{\partial r}, and dd, θ\theta and ν\nu are real parameters. This equation unifies the anomalous diffusion equation on fractals (ν=1\nu =1) and the spherical anomalous diffusion for porous media (θ=0\theta=0). Exact point-source solution is obtained, enabling us to describe a large class of subdiffusion (θ>(1ν)d\theta > (1-\nu)d), normal diffusion (θ=(1ν)d\theta= (1-\nu)d) and superdiffusion (θ<(1ν)d\theta < (1-\nu)d). Furthermore, a thermostatistical basis for this solution is given from the maximum entropic principle applied to the Tsallis entropy.Comment: 3 pages, 2 eps figure

    Anti-de Sitter curvature radius constrained by quasars in brane-world scenarios

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    This paper is intended to investigate the luminosity due to accretion of gas in supermassive black holes (SMBHs) in the center of quasars, using a brane-world scenario naturally endowed with extra dimensions, whereon theories formulated introduce corrections in the field equations at high energies. SMBHs possess the necessary highly energetic environment for the introduction of these corrections, which are shown to produce small deviations in all SMBH properties and, consequentely, corrections in the accretion theory that supports quasars radiative processes. The radiative flux observed from quasars indicates these deviations, from which the magnitude of the AdS5_5 bulk curvature radius, and consequently the extra dimension compactification radius is estimated.Comment: 11 pages, RevTeX, Eq.(2) and (3) expanded, and comments thereon update

    Small-q phonon-mediated superconductivity in organic \kappa-BEDT-TTF compounds

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    We propose a mew picture for superconductivity in κ(BEDTTTF)2X\kappa-(BEDT-TTF)_2X salts arguing that small-{\bf q} electron-phonon scattering dominates the pairing. We reproduce the distinct X-shaped d-wave gap reported recently by magnetooptic measurements and we argue that the softness of the momentum structure of the gap and the near degeneracy of s- and d-wave gap states may be at the origin of the experimental controversy about the gap symmetry. We show that a magnetic field applied parallel to the planes may induce extended gapless-regions on the FS accounting for the experimental signatures of a Fulde-Ferrel-Larkin-Ovchinikov state and it may induce gap symmetry transitions as well.Comment: 4 pages and 7 figure

    On-chain electrodynamics of metallic (TMTSF)_2 X salts: Observation of Tomonaga-Luttinger liquid response

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    We have measured the electrodynamic response in the metallic state of three highly anisotropic conductors, (TMTSF)_2 X, where X=PF_6, AsF_6, or ClO_4, and TMTSF is the organic molecule tetramethyltetraselenofulvalene. In all three cases we find dramatic deviations from a simple Drude response. The optical conductivity has two features: a narrow mode at zero frequency, with a small spectral weight, and a mode centered around 200 cm^{-1}, with nearly all of the spectral weight expected for the relevant number of carriers and single particle bandmass. We argue that these features are characteristic of a nearly one-dimensional half- or quarter-filled band with Coulomb correlations, and evaluate the finite energy mode in terms of a one-dimensional Mott insulator. At high frequencies (\hbar\omega > t_\perp, the transfer integral perpendicular to the chains), the frequency dependence of the optical conductivity \sigma_1(\omega) is in agreement with calculations based on an interacting Tomonaga-Luttinger liquid, and is different from what is expected for an uncorrelated one-dimensional semiconductor. The zero frequency mode shows deviations from a simple Drude response, and can be adequately described with a frequency dependent mass and relaxation rate.Comment: 12 pages, 7 figures, RevTeX; minor corrections to text and references; To be published in Phys. Rev. B, 15 July 199

    Plasma levels of matrix metalloproteinase-2, -3, -10, and tissue inhibitor of metalloproteinase-1 are associated with vascular complications in patients with type 1 diabetes: The EURODIAB Prospective Complications Study

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    Impaired regulation of extracellular matrix remodeling by matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinase (TIMP) may contribute to vascular complications in patients with type 1 diabetes. We investigated associations between plasma MMP-1, -2, -3, -9, -10 and TIMP-1, and cardiovascular disease (CVD) or microvascular complications in type 1 diabetic patients. We also evaluated to which extent these associations could be explained by low-grade inflammation (LGI) or endothelial dysfunction (ED). Methods: 493 type 1 diabetes patients (39.5 ± 9.9 years old, 51% men) from the EURODIAB Prospective Complications Study were included. Linear regression analysis was applied to investigate differences in plasma levels of MMP-1, -2, -3, -9, -10, and TIMP-1 between patients with and without CVD, albuminuria or retinopathy. All analyses were adjusted for age, sex, duration of diabetes, Hba1c and additionally for other cardiovascular risk factors including LGI and ED. Results: Patients with CVD (n = 118) showed significantly higher levels of TIMP-1 [β = 0.32 SD (95%CI: 0.12; 0.52)], but not of MMPs, than patients without CVD (n = 375). Higher plasma levels of MMP-2, MMP-3, MMP-10 and TIMP-1 were associated with higher levels of albuminuria (p-trends were 0.028, 0.004, 0.005 and 0.001, respectively). Severity of retinopathy was significantly associated with higher levels of MMP-2 (p-trend = 0.017). These associations remained significant after further adjustment for markers of LGI and ED. Conclusions: These data support the hypothesis that impaired regulation of matrix remodeling by actions of MMP-2, -3 and-10 and TIMP-1 contributes to the pathogenesis of vascular complications in type 1 diabetes
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