Quasi-degenerate neutrinos and tri-bi-maximal mixing

Assuming high-energy tri-bi-maximal mixing we study the radiative running of leptonic mixing angles and obtain limits on the high-energy scale from requiring consistency with the observed mixing. We construct a model in which a non-Abelian discrete family symmetry leads both to a quasi-degenerate neutrino mass spectrum and to near tri-bi-maximal mixing.Comment: 7 pages, to appear in the proceedings of DISCRETE'0

Pimenta-do-reino em Rondônia.

Esta publicação tem como objetivo caracterizar a cultura da pimenta-do-reino em Rondônia, plantio, solos aptos para o cultivo, colheita e beneficiamento.bitstream/item/76382/1/folder-pimentadoreino.pd

The WFCAM Multi-wavelength Variable Star Catalog

Stellar variability in the near-infrared (NIR) remains largely unexplored. The exploitation of public science archives with data-mining methods offers a perspective for the time-domain exploration of the NIR sky. We perform a comprehensive search for stellar variability using the optical-NIR multi-band photometric data in the public Calibration Database of the WFCAM Science Archive (WSA), with the aim of contributing to the general census of variable stars, and to extend the current scarce inventory of accurate NIR light curves for a number of variable star classes. We introduce new variability indices designed for multi-band data with correlated sampling, and apply them for pre-selecting variable star candidates, i.e., light curves that are dominated by correlated variations, from noise-dominated ones. Pre-selection criteria are established by robust numerical tests for evaluating the response of variability indices to colored noise characteristic to the data. We find 275 periodic variable stars and an additional 44 objects with suspected variability with uncertain periods or apparently aperiodic variation. Only 44 of these objects had been previously known, including 11 RR~Lyrae stars in the outskirts of the globular cluster M3 (NGC~5272). We provide a preliminary classification of the new variable stars that have well-measured light curves, but the variability types of a large number of objects remain ambiguous. We classify most of the new variables as contact binary stars, but we also find several pulsating stars, among which 34 are probably new field RR~Lyrae and 3 are likely Cepheids. We also identify 32 highly reddened variable objects close to previously known dark nebulae, suggesting that these are embedded young stellar objects. We publish our results and all light-curve data as the WFCAM Variable Star Catalog.Comment: 21 pages, 11 figure

Açaí (Euterpe spp.): características, formação de mudas e plantio para a produção de frutos.

Este trabalho teve como objetivo apresentar informações técnicas gerais sobre as características do açaizeiro, produção de mudas, plantio e manejo para a produção de frutos.bitstream/item/24775/1/ct80-acai.pd

Associação entre patologia espermática e perda da motilidade do espermatozoide caprino congelado na presença de Catalase.

O objetivo deste estudo foi determinar as relações entre a morfologia espermática no sêmen fresco e motilidade pós-descongelação no sêmen caprino criopreservado em diluente contendo Catalase. Dezesseis ejaculados foram coletados de três bodes da raça Alpina Americana. Após a avaliação do sêmen, as amostras foram classificadas de acordo com a morfologia espermática em dois grupos: A (total de espermatozoides anormais - TEA &#8805;30%, n=6) e B (TEA &#8804; 15%, n=10). O sêmen foi diluído em diluidor Tris-gema contendo Catalase (1, 5, ou 10 U/ml/400 x 106 espermatozoides) ou sem antioxidante (controle). Nas amostras do grupo A, a motilidade espermática (MT) média no sêmen fresco, foi 71% e o TEA 38%. Já no grupo B, a MT foi 86% e o TEA 14%. Após a descongelação, a MT, TEA, CD/F e CDG foram significativamente maiores (P < 0,05) no grupo A do que no B; enquanto que a TDM foi menor no grupo A. A adição de catalase em 1 e 5U/mL teve um efeito significativo (P <0,05) na MT e TDM no grupo A enquanto que acima de 5U/mL induziu uma diminuição na motilidade em ambos os grupos. O grupo com alto percentual de patologia espermática, possivelmente estava passando por estresse oxidativo e nesse caso, a adição de catalase foi suficiente para proteger as células contra a perda de motilidade

On the chromospheric activity of stars with planets

Context. Signatures of chromospheric activity enhancement have been found for a dozen stars, pointing to a possible star-planet interaction. Nevertheless in the coronal activity regime, there is no conclusive observational evidence for such an interaction. Does star-planet interaction manifest itself only for a few particular cases, without having a major effect on stars with planets in general? Aims. We aim to add additional observational constraints to support or reject the major effects of star-planet interactions in stellar activity, based on CaII chromospheric emission flux. Methods. We performed a statistical analysis of CaII emission flux of stars with planets, as well as a comparison between CaII and X-ray emission fluxes, searching for dependencies on planetary parameters. Results. In the present sample of stars with planets, there are no significant correlations between chromospheric activity indicator log(R'HK) and planetary parameters. Further, the distribution of the chromospheric activity indicator for stars without planets is not distinguishable from the one with planets.Comment: 6 pages, 5 figures, submitted to A&