Efeitos de variantes do gene da aromatase sobre caracteristicas de crescimento, reprotutivas e de habilidade materna em ovinos de uma população multirracial.

Resumo: Foi verificado o efeito das variantes do gene da aromatase sobre características produtivas e reprodutivas de ovinos de uma população multirracial. Para isto, fêmeas de diferentes grupos genéticos foram genotipadas e a influência do genótipo do animal sobre seu desempenho ou sobre o desempenho de suas crias foi analisada pelo método dos quadrados mínimos. Fêmeas BB apresentaram menor idade ao primeiro parto para o grupo genético ½ Dorper e menor intervalo de partos para a raça Santa Inês. Nestes mesmos grupos genéticos, as fêmeas AB apresentaram maiores pesos totais de crias desmamadas por matriz e por parto. Existem evidências que fêmeas BB apresentam melhores desempenhos reprodutivos, contrariamente às fêmeas AB que apresentam melhores habilidades maternas. Entretanto, maiores investigações são necessárias para comprovar estas evidências; [Allelic Frequency from Aromatase Gene in Meat Sheep]. Abstract: The effect of variants for aromatase gene on productive and reproductive traits in sheep from a multiracial population was verified. Females of different genetic groups were genotyped and the influence of the genotype of the animal on your performance or on the performance of yours lambs was analyzed by the least square method. BB females presented lower age at first lambing for ½ Dorper and lower lambing interval for Santa Inês breed. In these same genetic groups, AB females presented larger total weight of weaned lambs per female and per lambing. There are evidences that BB females presented better reproductive performance, contrarily to AB females that presented better maternal ability. However, more investigations are necessary to prove these evidences

Optical conductivity of URu2_2Si2_2 in the Kondo Liquid and Hidden-Order Phases

We measured the polarized optical conductivity of URu$_2$Si$_2$ from room temperature down to 5 K, covering the Kondo state, the coherent Kondo liquid regime, and the hidden-order phase. The normal state is characterized by an anisotropic behavior between the ab plane and c axis responses. The ab plane optical conductivity is strongly influenced by the formation of the coherent Kondo liquid: a sharp Drude peak develops and a hybridization gap at 12 meV leads to a spectral weight transfer to mid-infrared energies. The c axis conductivity has a different behavior: the Drude peak already exists at 300 K and no particular anomaly or gap signature appears in the coherent Kondo liquid regime. When entering the hidden-order state, both polarizations see a dramatic decrease in the Drude spectral weight and scattering rate, compatible with a loss of about 50 % of the carriers at the Fermi level. At the same time a density-wave like gap appears along both polarizations at about 6.5 meV at 5 K. This gap closes respecting a mean field thermal evolution in the ab plane. Along the c axis it remains roughly constant and it "fills up" rather than closing.Comment: 10 pages, 7 figure

Freqüência alélica do gene da aromatase em ovinos de corte.

Resumo: Com o objetivo de verificar a presença de polimorfismo e a freqüência dos alelos para o gene da aromatase (Cyp19), uma amostra de 71 animais da raça Santa Inês, 13 animais da raça Somalis Brasileira, 9 animais da raça Poll Dorset e 18 animais mestiços ½ Dorper foram genotipados pela técnica de PCR-RFLP. Nesta amostra, não foram observados indivíduos AA e as freqüências para os genótipos AB e BB foram 0,64 e 0,36, respectivamente. Foi observado que todos os animais da raça Somalis Brasileira eram de genótipo BB. Espera-se que estudos futuros venham comprovar a diferença de desempenho entre indivíduos de genótipos diferentes e assim incluir este gene como marcador molecular para seleção de animais superiores. [Allelic Frequency from Aromatase Gene in Meat Sheep]. Abstract: With the aim to verify the presence of polymorphism and the allelic frequency for aromatase gene (Cyp19), a sample of 71 animals of Santa Inês breed, 13 animals of Somalis Brasileira breed, 9 animal of Poll Dorset breed and 18 animals ½ Dorper crossbreed where genotyped by PCR-RFLP technique. In this sample, AA individuals were not observed and the frequencies for AB and BB genotypes were 0.64 and 0.36, respectively. All Somalis Brasileira animals were of genotype BB. It is waited that future studies come to prove the performance difference among animals with distinct genotypes and like this to include this gene as molecular marker for selection of superior animals

Infrared Signature of the Superconducting State in Pr(2-x)Ce(x)CuO(4)

We measured the far infrared reflectivity of two superconducting Pr(2-x)Ce(x)CuO(4) films above and below Tc. The reflectivity in the superconducting state increases and the optical conductivity drops at low energies, in agreement with the opening of a (possibly) anisotropic superconducting gap. The maximum energy of the gap scales roughly with Tc as 2 Delta_{max} / kB Tc ~ 4.7. We determined absolute values of the penetration depth at 5 K as lambda_{ab} = (3300 +/- 700) A for x = 0.15 and lambda_{ab} = (2000 +/- 300) A for x = 0.17. A spectral weight analysis shows that the Ferrell-Glover-Tinkham sum rule is satisfied at conventional low energy scales \~ 4 Delta_{max}.Comment: 4 pages, 4 figure