531 research outputs found

    Productive indicator in a Holstein dairy herd: growth and height curves, reproductive and productive traits and genetic parameters

    Get PDF
    Data on weight, height, productive and reproductive performance of 1,272 Holstein heifers, born from 1990 to 1998, were used to evaluate the growth and height patterns of these females from birth to first calving, and the following traits: weight at first calving (PP), age at first calving (IP), milk production in the first lactation (PL) and first calving interval (IEP), and to estimate genetic parameters of these traits. The von Bertalanffy fitted models were: Yi=802.10 (1-0.630EXP (-0.0022t)) for weight, and Yi=1.40 (1-0.208EXP (-0.0038t)) for height. The average performance of heifers were: height 140cm, weight 602kg and 27 month of age at first calving. The total milk yield was 8,026kg and first IEP was 420 days. The (co)variance components estimates were obtained by a derivative-free algorithm with the DFREML. The estimates of heritabilities were 0.31, 0.35, 0.34, respectively for PP, IP and PL, and 0.10 for IEP. The genetic correlations estimates between PP and PL, PL and IP and IEP and PL were low. The correlation between IEP and PP was 0.49 and between IEP and IP was, -0.69, sugesting an antagonism between the two last traits.Foram analisados dados de peso, altura e desempenho produtivo e reprodutivo de 1.272 novilhas da raça Holandesa, nascidas no período de 1990 a 1998. Estudaram-se o desenvolvimento em peso e altura do nascimento até o primeiro parto, as características peso ao primeiro parto (PP), idade ao primeiro parto (IP), produção de leite na primeira lactação (PL), primeiro intervalo de partos (IEP), e os parâmetros genéticos pertinentes. As equações para as curvas de peso e altura, estimadas pelo modelo proposto por von Bertalanffy, foram: Yi= 802,10 (1 - 0,630EXP (-0,0022t)) e Yi= 1,40 (1 - 0,208EXP (-0,0038t)), respectivamente. As novilhas atingiram o primeiro parto com altura média de 140cm e peso de 602kg aos 27 meses de idade. A produção total de leite na primeira lactação foi de 8.026kg e o primeiro IEP 420 dias. Na obtenção dos componentes de (co)variância utilizou-se o método da máxima verossimilhança restrita livre de derivada. As estimativas de herdabilidade foram 0,31, 0,35 e 0,34, respectivamente, para PP, IP e PL, e 0,10 para IEP, evidenciando variância genética aditiva média para as três primeiras características. As correlações genéticas apresentaram pequena magnitude para PP e PL, PL e IP, e IEP e PL. A correlação entre IEP e PP foi 0,49; entre IEP e IP o valor foi negativo, -0,69, indicando provável antagonismo entre as duas últimas características.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo (UNIFESP) Faculdade de Medicina de Ribeirão Preto Departamento de GenéticaUniversidade Estadual Paulista Faculdade de Medicina Veterinária e ZootecniaInstituto de ZootecniaUniversidade de São Paulo Escola Superior de Agricultura Luiz de QueirozUNIFESP, Faculdade de Medicina de Ribeirão Preto Depto. de GenéticaSciEL

    The phase transition and the Quasi-Normal Modes of black Holes

    Get PDF
    We reexamined the argument that the quasinormal modes could be a probe of the phase transition of a topological black hole to a hairy configuration by investigating general scalar perturbations. We found further evidence in the quasinormal modes for this phase transition. For the general black hole configurations, we observed that although the quasinormal modes can present us different phases of different configurations, there is no dramatic change in the slope of quasinormal frequencies at the critical point of the phase transition. More detailed studies of quasinormal modes are needed to reveal the subtle behavior of the phase transition.Comment: Revised version, accepted for publication in JHE

    Biomechanical analysis of PDMS channels using different hyperelastic constitutive models

    Get PDF
    Brain aneurysms are pathological dilatations of cerebral arteries and are known as one of the most common and serious cerebrovascular events. Most cerebral aneurysms do not cause symptoms until they become large, beginning to break up. This study's main objective is the numerical characterization of biomechanical behavior of aneurysms, taking into ac-count different geometric and physiological parameters, in order to analyze the blood vessel wall behavior during the formation of an aneurysm in order to understand what leads to its formation and where are most conducive to its rupture zones. Simulation of the Newtonian fluid flow (glycerin, with well-known properties and sufficient viscosity to measure the pressure drops) was performed using the commercial finite method package Ansys® - Fluent, and pressure along the channel was determined. These pressures were imported into the channel, in the Ansys®- Static Structural, in order to be able to evaluate and analyse the deformations and stresses in the channel wall, caused by internal pressure induced by the fluid flow. To do this, the most known hyper-elastic constitutive models were used. and it was concluded that any constitutive model can be applied to this kind of studies, allowing to visualize where pressure achieve maximums and consequently, the most favorable areas to the rupture

    Critical analysis of autoregressive and fast Fourier transform markers of cardiovascular variability in rats and humans

    Get PDF
    The autonomic nervous system plays an important role in physiological and pathological conditions, and has been extensively evaluated by parametric and non-parametric spectral analysis. To compare the results obtained with fast Fourier transform (FFT) and the autoregressive (AR) method, we performed a comprehensive comparative study using data from humans and rats during pharmacological blockade (in rats), a postural test (in humans), and in the hypertensive state (in both humans and rats). Although postural hypotension in humans induced an increase in normalized low-frequency (LFnu) of systolic blood pressure, the increase in the ratio was detected only by AR. In rats, AR and FFT analysis did not agree for LFnu and high frequency (HFnu) under basal conditions and after vagal blockade. The increase in the LF/HF ratio of the pulse interval, induced by methylatropine, was detected only by FFT. In hypertensive patients, changes in LF and HF for systolic blood pressure were observed only by AR; FFT was able to detect the reduction in both blood pressure variance and total power. In hypertensive rats, AR presented different values of variance and total power for systolic blood pressure. Moreover, AR and FFT presented discordant results for LF, LFnu, HF, LF/HF ratio, and total power for pulse interval. We provide evidence for disagreement in 23% of the indices of blood pressure and heart rate variability in humans and 67% discordance in rats when these variables are evaluated by AR and FFT under physiological and pathological conditions. The overall disagreement between AR and FFT in this study was 43%.FINEPFAPESPZerbini Foundatio

    Treatment of a submerged anaerobic membrane bioreactor (SAnMBR) effluent by an activated sludge system: the role of sulphide and thiosulphate in the process

    Full text link
    This work studies the use of a well-known and spread activated sludge system (UCT configuration) to treat the effluent of a submerged anaerobic membrane bioreactor (SAnMBR) treating domestic waste-water. Ammonia, phosphate, dissolved methane and sulphide concentrations in the SAnMBR effluent were around 55 mg NH4-N L-1, 7 mg PO4-P L-1, 30 mg non-methane biodegradable COD L-1, and 105 mg S2- L-1 respectively. The results showed a nitrification inhibition caused by the presence of sulphur compounds at any of the solids retention time (SRT) studied (15,20 and 25 days). This inhibition could be overcome increasing the hydraulic retention time (HRT) from 13 to 26 h. Among the sulphur compounds, sulphide was identified as the substance which caused the nitrification inhibition. When the nitrification was well established, removal rates of nitrogen and phosphorus of 56% and 45% were reached respectively. The sulphide present in the influent was completely oxidised to sulphate, contributing this oxidation to the denitrification process. Moreover, the presence of methanotrophic bacteria, detected by FISH technique, could also contribute to the denitrification. (C) 2014 Elsevier Ltd. All rights reserved.This research project has been supported by Ministry of Science and Innovation (project CTM2011-28595-C02-01/02) and University of Valencia (precompetitive project UV-INV-AE11-40539) which is gratefully acknowledged.Sánchez Ramírez, JE.; Seco Torrecillas, A.; Ferrer, J.; Bouzas Blanco, A.; García Usach, MF. (2015). Treatment of a submerged anaerobic membrane bioreactor (SAnMBR) effluent by an activated sludge system: the role of sulphide and thiosulphate in the process. Journal of Environmental Management. 147:213-218. https://doi.org/10.1016/j.jenvman.2014.04.043S21321814

    Coset Space Dimensional Reduction and Wilson Flux Breaking of Ten-Dimensional N=1, E(8) Gauge Theory

    Full text link
    We consider a N=1 supersymmetric E(8) gauge theory, defined in ten dimensions and we determine all four-dimensional gauge theories resulting from the generalized dimensional reduction a la Forgacs-Manton over coset spaces, followed by a subsequent application of the Wilson flux spontaneous symmetry breaking mechanism. Our investigation is constrained only by the requirements that (i) the dimensional reduction leads to the potentially phenomenologically interesting, anomaly free, four-dimensional E(6), SO(10) and SU(5) GUTs and (ii) the Wilson flux mechanism makes use only of the freely acting discrete symmetries of all possible six-dimensional coset spaces.Comment: 45 pages, 2 figures, 10 tables, uses xy.sty, longtable.sty, ltxtable.sty, (a shorter version will be published in Eur. Phys. J. C

    The Saffman-Taylor problem on a sphere

    Full text link
    The Saffman-Taylor problem addresses the morphological instability of an interface separating two immiscible, viscous fluids when they move in a narrow gap between two flat parallel plates (Hele-Shaw cell). In this work, we extend the classic Saffman-Taylor situation, by considering the flow between two curved, closely spaced, concentric spheres (spherical Hele-Shaw cell). We derive the mode-coupling differential equation for the interface perturbation amplitudes and study both linear and nonlinear flow regimes. The effect of the spherical cell (positive) spatial curvature on the shape of the interfacial patterns is investigated. We show that stability properties of the fluid-fluid interface are sensitive to the curvature of the surface. In particular, it is found that positive spatial curvature inhibits finger tip-splitting. Hele-Shaw flow on weakly negative, curved surfaces is briefly discussed.Comment: 26 pages, 4 figures, RevTex, accepted for publication in Phys. Rev.
    • …
    corecore