5,744 research outputs found
Dilatonic, Current-Carrying Cosmic String
We study the implications of a scalar-tensorial gravity for the metric of an
isolated self-gravitating superconducting cosmic string. These modifications
are induced by an arbitrary coupling of a massless scalar field to the usual
tensorial field in the gravitational Lagrangian. We derive the metric in the
weak-field approximation and we analyse the behaviour of light in this
spacetime. We end with some discussions.Comment: 12 pp, Latex, no figures, based on a talk given by M. E. X. Guimaraes
at the COSMO 99, 27/9 to 02/10/99, ICTP, Trieste, I
On the duality in four-dimensional Lorentz-breaking field theories
We consider new issues of duality in four-dimensional Lorentz-breaking field
theories. In particular, we demonstrate that the arising of the aether-like
Lorentz-breaking term is necessary in order for the 4D models to display the
duality analog between the MCS and self-dual models in 3D. We further study the
dispersion relations in both theories and discuss the physical contents of the
models involved in this new dualilty.Comment: 16 page
Evaluation of high quality protein maize (QPM) hybrids obtained by conversion of normal inbred lines.
Two experimental QPM hybrids obtained by lhe partial conversion of three elite inbred lines by modified backcrossing were evaluated and compared to the normal versions of the same hybrids. Thirteen agronomic and 12 grain quality traits were evaluated. The hybrids were also anaJyzed by SSR markers in order to evaluate the genetic relationship among them. Results demonstrated that the converted QPM hybrids presented a better protein quality and a similar agronomic performance for most of the evaluated traits, including grain yield, in comparison to their normal versions. However, some of the deficiencies generally ascribed to QPM hybrids, such as a higher lodgíng percentage, thicker cobs, and shorter kernels were maintained up to this stage of the conversion process. In comparison to more recent elite hybrids, the normal versions as well as the converted QPM hybrids presented the worst performances in relation to the grain yield, thus indicating a loss of competitiveness
Genetic diversity and population structure assessed by SNP markers in a panel of maize inbred lines.
Mapeamento de locos de características quantitativas associados à composição de carcaça, no cromossomo seis de suíno
Uma população de suínos, composta de 550 animais F2, foi produzida a partir do intercruzamento da geração FI, obtida pelo cruzamento divergente de dois machos da raça nativa brasileira Piau com 18 fêmeas comerciais. O objetivo do trabalho foi mapear locos de características quantitativas (QTL) associados a cortes de carcaça. Os animais foram genotipados para I3 marcadores microssatélites, distribuídos no cromossomo 6 de suínos. As características avaliadas foram: peso total do pernil, peso do pernil sem pele e sem capa de gordura, peso total da copa, peso da copa sem pele e sem capa de gordura, peso total da paleta, peso da paleta sem pele e sem capa de gordura, peso total do carré, peso do lombo, peso total do bacon, peso das costelas, peso total da papada, peso do filezinho e peso da banha rama. Utilizou-se o método de regressão por intervalo de mapeamento por meio do programa QTL Express. Foram encontrados indicativos de QTL para peso de pernil limpo, peso de paleta, peso de lombo e peso de filezinho. A região genõmica deve ser saturada com marcadores adicionais para confirmar a presença de QTL reais
Selection of sorghum hybrids grown under aluminum saturation.
The purpose of this study was to evaluate 165 hybrids derived from lines previously selected for aluminum (Al) tolerance. Nine check cultivars were used, eight commercial hybrids and one experimental hybrid. Hybrids were evaluated at three levels of Al saturation (0, 20 and 40% on average). The differences between the environments were significant. Environment with 0% Al saturation yielded 29.5% more than that with 40% Al saturation, showing the importance of genotype selection for acid soils. The best check cultivar was the hybrid DKB550. The hybrids AG1020 and AG1040 also performed well, where the latter was more tolerant but the former more responsive to environment improvement. The hybrid BRS304 was susceptible to high levels of Al saturation. The three commercial BRS hybrids (BRS310, BRS330 and BRS332) performed better than BRS304 at high Al saturation. The hybrid BRS330 was the best BRS hybrid to grow on a field with high Al saturation. The hybrid DKB559 performed well at high Al saturation but did not respond to environment improvement. The hybrids 727029, 727039, 729041, 729095, 729109, AG1040, and DKB550 were tolerant to higher levels of Al saturation and responsive to environment improvement, and showed good stability and adaptability at both low and high Al saturation
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