3,455 research outputs found
Solutions to CDM Universe Derived from Global Brane Model
An exact solution of brane universe is studied and the result indicates that
Friedmann equations on the brane are modified with an extra term. This term can
play the role of dark energy and make the universe accelerate. In order to
derive the CDM Universe from this global brane model, the new
solutions are obtained to describe the manifold.Comment: 7 pages, no figure, accepted by MPL
The Real Scalar Field Equation for Nariai Black Hole in the 5D Schwarzschild-de Sitter Black String Space
The Nariai black hole, whose two horizons are lying close to each other, is
an extreme and important case in the research of black hole. In this paper we
study the evolution of a massless scalar field scattered around in 5D
Schwarzschild-de Sitter black string space. Using the method shown by Brevik
and Simonsen (2001) we solve the scalar field equation as a boundary value
problem, where real boundary condition is employed. Then with convenient
replacement of the 5D continuous potential by square barrier, the reflection
and transmission coefficients () are obtained. At last, we also compare
the coefficients with usual 4D counterpart.Comment: 10 pages,6 figures.To appear in Int. J. Mod. Phys.
Quantum Statistical Entropy and Minimal Length of 5D Ricci-flat Black String with Generalized Uncertainty Principle
In this paper, we study the quantum statistical entropy in a 5D Ricci-flat
black string solution, which contains a 4D Schwarzschild-de Sitter black hole
on the brane, by using the improved thin-layer method with the generalized
uncertainty principle. The entropy is the linear sum of the areas of the event
horizon and the cosmological horizon without any cut-off and any constraint on
the bulk's configuration rather than the usual uncertainty principle. The
system's density of state and free energy are convergent in the neighborhood of
horizon. The small-mass approximation is determined by the asymptotic behavior
of metric function near horizons. Meanwhile, we obtain the minimal length of
the position which is restrained by the surface gravities and the
thickness of layer near horizons.Comment: 11pages and this work is dedicated to the memory of Professor Hongya
Li
Proteins to Order Use of Synthetic DNA to Generate Site-Specific Mutations
The ability to cause specific changes in the amino acid
sequences of proteins would greatly advance studies on the
influence of protein structure on biochemical function. If
the desired changes can once be made in the nucleic acid
which encodes the protein, one can use cloning in an appropriate microorganism to produce essentially limitless
quantities of the mutant protein. We describe here the
application of oligonucleotide-directed site-specific mutagenesis to accomplish this objective for the enzyme
B-lactamase, the gene for which is contained in the plasmid
pBR322. The method uses a procedure to screen for mutant clones which depends on the DNA in the various colonies and not on the properties of the mutant protein; the method can, therefore, be widely applied and does not require, in each separate case, the development of a screening procedure which depends on some phenotypic difference between mutant and wild-type protein
Medida de condutividade elétrica do solo adaptada a uma plantadeira.
bitstream/CNPDIA-2009-09/11888/1/CiT46_2008.pd
Resultados da experimentação de genótipos de trigo para aptidão a duplo propósito no Paraná, em 2000.
bitstream/item/84114/1/CNPT-BOL.-PESQ.-6-01.pd
Is genotyping of single isolates sufficient for population structure analysis of <i>Pseudomonas aeruginosa</i> in cystic fibrosis airways?
The primary cause of morbidity and mortality in cystic fibrosis (CF) patients is lung infection by Pseudomonas aeruginosa. Therefore much work has been done to understand the adaptation and evolution of P. aeruginosa in the CF lung. However, many of these studies have focused on longitudinally collected single isolates, and only few have included cross-sectional analyses of entire P. aeruginosa populations in sputum samples. To date only few studies have used the approach of metagenomic analysis for the purpose of investigating P. aeruginosa populations in CF airways. We analysed five metagenomes together with longitudinally collected single isolates from four recently chronically infected CF patients. With this approach we were able to link the clone type and the majority of SNP profiles of the single isolates to that of the metagenome(s) for each individual patient. Based on our analysis we find that when having access to comprehensive collections of longitudinal single isolates it is possible to rediscover the genotypes of the single isolates in the metagenomic samples. This suggests that information gained from genome sequencing of comprehensive collections of single isolates is satisfactory for many investigations of adaptation and evolution of P. aeruginosa to the CF airways
Modeling of Ni Diffusion Induced Austenite Formation in Ferritic Stainless Steel Interconnects
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