1,491 research outputs found
Genetic evaluation of partial growth trajectory of Santa Inês breed using random regression models.
ABSTRACT - It was evaluated data set of 19,303 weight records of Santa Inês sheep in order to evaluate distinct polynomial functions with different order for better adjustements of fixed and random regressions of growth trajectory and to estimate (co)variances components and genetic parameters of this trajectory. Fixed effects used in analysis were contemporary group, sex and birth type. Ordinary and Legendre polynomials, ranging from two to four orders, were evaluated for fixed regression of average growth trajectory. Legendre and quadratic b-spline functions, ranging from three to four orders, were evaluated for random regressions. Legendre polynomials of order fourth were suitable to fit random regression, while ordinary polynomials of third order were the best for fixed trajectory. Direct heritabilities on days 1, 50, 150, 250 and 411 were 0.24, 0.12, 0.44, 0.84, and 0.96, respectively, while maternal heritabilities for the same ages were 0.24, 0.19, 0.09, 0.02, and 0.01, respectively. Genetic correlations among weights in subsequent ages were high, tending to unity, and there were negative correlations between weights at early ages and weights at late ages. It is possible to modify the growth trajectory by selection with the observed genetic variability. Genetic control of weights at initial ages is not the same in late ages. So, selection of animals for slaughter in early age must be different from that of replacement animals. Avaliação genética de parte da trajetória de crescimento em ovinos da raça Santa Inês utilizando modelos de regressão aleatória. Resumo - Foram utilizados 19.303 registros de peso de ovinos da raça Santa Inês com os objetivos de avaliar funções polinomiais com diferentes ordens para melhor ajuste das regressões fixas e aleatórias da trajetória de crescimento e estimar os componentes de covariância e os parâmetros genéticos desta trajetória. Os efeitos fixos utilizados nas análises foram grupo de contemporâneos, sexo e tipo de nascimento. Para ajuste da regressão fixa da trajetória média de crescimento, foram avaliados polinômios ordinários e de Legendre com ordens variando de 2 a 4. Para as regressões aleatórias, foram avaliadas as funções de Legendre e ?-spline quadrática, com ordens variando de 3 a 4. As funções com polinômios de Legendre de quarta ordem foram adequadas para ajustar a parte aleatória, enquanto os polinômios ordinários de terceira ordem foram melhores para ajustar a parte fixa. As herdabilidades diretas nos dias 1, 50, 150, 250 e 411 foram de 0,24; 0,12; 0,44; 0,84; e 0,96, respectivamente, enquanto as herdabilidades maternas nessas idades foram de 0,24; 0,19; 0,09; 0,02 e 0,01. As correlações genéticas entre pesos em idades subsequentes foram elevadas, tendendo à unidade, e houve correlações negativas entre pesos tomados em idades mais jovens e aqueles tomados em idades mais avançadas. A variabilidade genética observada permite alterar a trajetória de crescimento por meio de seleção. O controle genético dos pesos nas fases iniciais do crescimento não é o mesmo que atua em idades mais tardias. Assim, a seleção de animais para abate em idade jovem deve ser diferente daquela para animais de reposição no rebanho
Características raciais de ovinos da raça Morada Nova e seus impactos sobre o descarte involuntário de animais: resultados preliminares.
Resumo: Objetivou-se com esse trabalho, verificar a existência de associação entre os caracteres raciais de ovinos da raça Morada Nova e sua conseqüência no descarte involuntário dos animais. Utilizou se dados descritores de pigmentação do espelho nasal e dos cascos, cor da pelagem, criptorquidismo (unilateral ou bilateral) e presença de chifre. O banco continha informações de 181 animais, sendo 91 fêmeas e 90 machos. Apenas 45,3% dos animais apresentavam mais de 50% de cascos e espelho nasal pigmentados. Não foi observado nenhum animal de pelagem preta de casco e espelho nasal despigmentado. Observou-se que 22,22% dos machos apresentavam chifres (ou rudimento) e não apresentavam criptorquidismo, enquanto 16,67% dos machos não apresentam chifres, entretanto, eram criptorquídicos. Observou-se pelo teste qui-quadrado que a associação entre a pigmentação do espelho nasal e a pigmentação dos cascos foi significativa (P<0,05). Os resultados indicam a necessidade de uma reavaliação no padrão da raça Morada Nova, de forma a permitir que haja seleção para características de interesse econômico que não as raciais. Contudo, esses resultados são preliminares e estudos mais aprofundados com outros rebanhos são necessários para inferências mais conclusivas. Phenotypics Characteristics on Morada Nova Breed Sheep. Abstract: The aim of this study was to examine the association between racial characters in Morada Nova hair sheep breedand its consequence in involuntary culling of animals. Data from pigmentation of the muzzle and the hoof, coat color, cryptorchid (unilateral or bilateral) and presence of horns. Data from 181 animals, 91 females and 90 males were used. Only 45.3% of animals showed more than 50% of hoofs and muzzle pigmented. All black coat animals had hoofs and muzzle pigmented. it was found that 22.22% of males had horns (or rudiments) and had no cryptorchid while 16.67% of the males had absence of horns and were cryptorchidism. Therefore, the association between the pigmentation of the muzzle and the pigmentation of the hoofs was significant (P <0.05). The results indicate the need for a reassessment in the pattern of Morada Nova breed to allow that the selection for traits of economic interest and not racial. However, these results are preliminary and more depth studies with other flocks are necessary for more conclusive inferences
Traversable wormholes coupled to nonlinear electrodynamics
In this work we explore the possible existence of static, spherically
symmetric and stationary, axisymmetric traversable wormholes coupled to
nonlinear electrodynamics. Considering static and spherically symmetric (2+1)
and (3+1)-dimensional wormhole spacetimes, we verify the presence of an event
horizon and the non-violation of the null energy condition at the throat. For
the former spacetime, the principle of finiteness is imposed, in order to
obtain regular physical fields at the throat. Next, we analyze the
(2+1)-dimensional stationary and axisymmetric wormhole, and also verify the
presence of an event horizon, rendering the geometry non-traversable.
Relatively to the (3+1)-dimensional stationary and axisymmetric wormhole
geometry, we find that the field equations impose specific conditions that are
incompatible with the properties of wormholes. Thus, we prove the non-existence
of the general class of traversable wormhole solutions, outlined above, within
the context of nonlinear electrodynamics.Comment: 9 pages, Revtex4. V2: major change in title; considerable additions
in the Introduction and in the rotating solution, no physics changes;
correction of a reference, one reference added; now 10 pages. This version to
appear in Classical and Quantum Gravit
Single marker assisted selection in Brazilian Morada Nova hair sheepcommunity-based breeding program.
Abstract: Morada Nova hair sheep show traits desirable for lamb production especially in extensive production systems in Northeastern Brazil, representing an important genetic resource for producing lamb in semi-arid climates in Brazil and elsewhere. Performance testing has been carried out annually with this breed since 2008. In the present study, Morada Nova sheep from two Brazilian states: Ceará (140 animals) and São Paulo (112 animals) were genotyped for a SNP associated with litter size, which is almost only found in Brazilian locally adapted sheep breeds (FecGE). The total observed frequency of FecGE was 0.65, while an increased number of observed heterozygotes was also observed (?2 = 7.274, p< 0.01). No significant FecGE allele frequency differences were observed (p = 0.3708) in 139 performance-tested rams classified as Elite/Superior or Regular/Inferior in the states of Ceará and São Paulo. Considering that litter size has been shown to positively affect farm profitability in medium to high input systems, we suggest that inclusion of FecGE genotyping information in future selection indexes estimated with basis on performance test data, fine-tuned to regional production systems may contribute to increase profitability gains observed in the Morada Nova community-based breeding program
f(R,L_m) gravity
We generalize the type gravity models by assuming that the
gravitational Lagrangian is given by an arbitrary function of the Ricci scalar
and of the matter Lagrangian . We obtain the gravitational field
equations in the metric formalism, as well as the equations of motion for test
particles, which follow from the covariant divergence of the energy-momentum
tensor. The equations of motion for test particles can also be derived from a
variational principle in the particular case in which the Lagrangian density of
the matter is an arbitrary function of the energy-density of the matter only.
Generally, the motion is non-geodesic, and takes place in the presence of an
extra force orthogonal to the four-velocity. The Newtonian limit of the
equation of motion is also considered, and a procedure for obtaining the
energy-momentum tensor of the matter is presented. The gravitational field
equations and the equations of motion for a particular model in which the
action of the gravitational field has an exponential dependence on the standard
general relativistic Hilbert--Einstein Lagrange density are also derived.Comment: 6 pages, no figures; minor modifications, references added; accepted
for publication in EPJ
Goal-directed fluid management based on pulse pressure variation monitoring during high-risk surgery: a pilot randomized controlled trial
Abstract\ud
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Introduction\ud
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Several studies have shown that maximizing stroke volume (or increasing it until a plateau is reached) by volume loading during high-risk surgery may improve post-operative outcome. This goal could be achieved simply by minimizing the variation in arterial pulse pressure (ΔPP) induced by mechanical ventilation. We tested this hypothesis in a prospective, randomized, single-centre study. The primary endpoint was the length of postoperative stay in hospital.\ud
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Methods\ud
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Thirty-three patients undergoing high-risk surgery were randomized either to a control group (group C, n = 16) or to an intervention group (group I, n = 17). In group I, ΔPP was continuously monitored during surgery by a multiparameter bedside monitor and minimized to 10% or less by volume loading.\ud
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Results\ud
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Both groups were comparable in terms of demographic data, American Society of Anesthesiology score, type, and duration of surgery. During surgery, group I received more fluid than group C (4,618 ± 1,557 versus 1,694 ± 705 ml (mean ± SD), P < 0.0001), and ΔPP decreased from 22 ± 75 to 9 ± 1% (P < 0.05) in group I. The median duration of postoperative stay in hospital (7 versus 17 days, P < 0.01) was lower in group I than in group C. The number of postoperative complications per patient (1.4 ± 2.1 versus 3.9 ± 2.8, P < 0.05), as well as the median duration of mechanical ventilation (1 versus 5 days, P < 0.05) and stay in the intensive care unit (3 versus 9 days, P < 0.01) was also lower in group I.\ud
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Conclusion\ud
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Monitoring and minimizing ΔPP by volume loading during high-risk surgery improves postoperative outcome and decreases the length of stay in hospital.\ud
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Trial registration\ud
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NCT00479011The authors thank Maria De Amorim (Paris, France) and Julia Fukushima (São Paulo, SP, Brazil) for help in data analysis, Dr Julia Wendon (London, UK) for reviewing the manuscript, and Dixtal (Sao Paulo, SP, Brazil) for providing the software for the automatic calculation of ?PP.The authors thank Maria De Amorim (Paris, France) and Julia Fukushima (São Paulo, SP, Brazil) for help in data analysis, Dr Julia Wendon (London, UK) for reviewing the manuscript, and Dixtal (Sao Paulo, SP, Brazil) for providing the software for the automatic calculation of ?PP
Differential (2+1) Jet Event Rates and Determination of alpha_s in Deep Inelastic Scattering at HERA
Events with a (2+1) jet topology in deep-inelastic scattering at HERA are
studied in the kinematic range 200 < Q^2< 10,000 GeV^2. The rate of (2+1) jet
events has been determined with the modified JADE jet algorithm as a function
of the jet resolution parameter and is compared with the predictions of Monte
Carlo models. In addition, the event rate is corrected for both hadronization
and detector effects and is compared with next-to-leading order QCD
calculations. A value of the strong coupling constant of alpha_s(M_Z^2)=
0.118+- 0.002 (stat.)^(+0.007)_(-0.008) (syst.)^(+0.007)_(-0.006) (theory) is
extracted. The systematic error includes uncertainties in the calorimeter
energy calibration, in the description of the data by current Monte Carlo
models, and in the knowledge of the parton densities. The theoretical error is
dominated by the renormalization scale ambiguity.Comment: 25 pages, 6 figures, 3 tables, submitted to Eur. Phys.
Measurements of Transverse Energy Flow in Deep-Inelastic Scattering at HERA
Measurements of transverse energy flow are presented for neutral current
deep-inelastic scattering events produced in positron-proton collisions at
HERA. The kinematic range covers squared momentum transfers Q^2 from 3.2 to
2,200 GeV^2, the Bjorken scaling variable x from 8.10^{-5} to 0.11 and the
hadronic mass W from 66 to 233 GeV. The transverse energy flow is measured in
the hadronic centre of mass frame and is studied as a function of Q^2, x, W and
pseudorapidity. A comparison is made with QCD based models. The behaviour of
the mean transverse energy in the central pseudorapidity region and an interval
corresponding to the photon fragmentation region are analysed as a function of
Q^2 and W.Comment: 26 pages, 8 figures, submitted to Eur. Phys.
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