4,884 research outputs found
Remote sensing applied to geological mapping; comparative geomorphology and identification of mineral zones of zinc and lead in the region of Vazante, MG
The author has identified the following significant results. Results showed that the black and white aerial photographs and the color infrared transparencies were efficient for mapping of three lithological units of the Paraopeba formation and for mineralized zones identification, respectively. Multispectral transparencies of I2S made it easier to separate dolomites, which were the rocks conditioning zinc and lead mineralization. Statistical analysis of morphometric indexes obtained from black and white photographs and topographic charts showed significant difference among three lithological units of Paraopeba formation which can be defined as Crest, Hilly, and Karstic reliefs
The solar, exoplanet and cosmological lithium problems
We review three Li problems. First, the Li problem in the Sun, for which some
previous studies have argued that it may be Li-poor compared to other Suns.
Second, we discuss the Li problem in planet hosting stars, which are claimed to
be Li-poor when compared to field stars. Third, we discuss the cosmological Li
problem, i.e. the discrepancy between the Li abundance in metal-poor stars
(Spite plateau stars) and the predictions from standard Big Bang
Nucleosynthesis. In all three cases we find that the "problems" are naturally
explained by non-standard mixing in stars.Comment: Astrophysics and Space Science, in press. New version has one
reference correcte
Some applications of excited-state-excited-state transition densities
We derive an approximation for transition moments between excited states consistent with the approximations and assumptions normally used to obtain transition moments betwen the ground and excited states in the random-phase approximation and its higher-order approximations. We apply the result to the calculation of the photoionization cross sections of the 23S and 21S metastable states of helium by a numerical analytical continuation of the frequency-dependent polarizability. The procedure completely avoids the need for continuum basis functions. The cross sections agree well with the results of other calculations. We also predict an accurate two-photon decay rate for the 21S metastable state of helium. The entire procedure is immediately applicable to several problems involving photoionization of metastable states of molecules
Engorda de pirarucus (Arapaima gigas) em associação com búfalos e suínos.
bitstream/item/34085/1/CPATU-CirTec65.pd
Divergência genética entre genótipos de aceroleira da Embrapa Semiárido.
O presente trabalho teve como objetivo a análise da divergência genética em um grupo de genótipos de aceroleira do programa de melhoramento genético da Embrapa Semiárido
Caracterização preliminar de acessos de aceroleira da Embrapa Semiárido.
O presente trabalho objetivou a caracterização preliminar dos acessos do Banco Ativo de Germoplasma (BAG) de Aceroleira da Embrapa Semiárido
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