5,058 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
Genetic control of traits related to phosphorus use efficiency in tropical maize.
Knowing the inheritance of traits is essential to establish selection strategies in breeding programs. The aim of this study was to determine the genetic control of traits related to the phosphorus use efficiency in maize. A total of 280 progenies were developed according to design III, which were evaluated in the field under high and low phosphorus (P) availability. The genetic variance components were estimated for the agronomic traits and indices that define P use efficiency. The results indicated that the additive and dominance effects were important in explaining the genetic variability for the flowering time, grain yield and P efficiency indices. However, dominance effects prevailed, indicating that breeding efforts should be made to develop hybrids exploiting the heterosis for traits related to P use efficiency
Utilização de marcadores SSR como ferramenta auxiliar na análise de fatores associados a dureza do grão em milho.
xSuplemento. Edição dos resumos do 46º Congresso Nacional de Genética, Águas de Lindóia, SP, 2000
Gribov horizon and i-particles: about a toy model and the construction of physical operators
Restricting the functional integral to the Gribov region leads to a
deep modification of the behavior of Euclidean Yang-Mills theories in the
infrared region. For example, a gluon propagator of the Gribov type,
, can be viewed as a propagating pair of
unphysical modes, called here -particles, with complex masses . From this viewpoint, gluons are unphysical and one can see them as
being confined. We introduce a simple toy model describing how a suitable set
of composite operators can be constructed out of -particles whose
correlation functions exhibit only real branch cuts, with associated positive
spectral density. These composite operators can thus be called physical and are
the toy analogy of glueballs in the Gribov-Zwanziger theory.Comment: 35 pages, 10 .pdf figures. v2: version accepted for publication in
Physical Review
Divergência molecular entre linhagens de milho desenvolvidas sob baixa disponibilidade de nitrogênio.
Caracterização molecular de milho e sorgo para aplicação nos programas de melhoramento da Embrapa.
bitstream/CNPMS-2010/22577/1/Com-177.pd
Retrocruzamentos auxiliados por marcadores moleculares para conversão de linhagens normais em milho de alta qualidade protéica (QPM).
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