6,878 research outputs found
Investigation into the site and mode of antivertigo action of a new phenothiazine derivative Final report
Cerebellum site and mode of antivertigo action of thiethylperazin
Non-stationary de Sitter cosmological models
In this note it is proposed a class of non-stationary de Sitter, rotating and
non-rotating, solutions of Einstein's field equations with a cosmological term
of variable function.Comment: 11 pages, Latex. International Journal of Modern Physics D (accepted
for publication
Electrical conductivity and thermal behavior of solid electrolytes based on alkali carbonates and sulfates
Both thermal stability and electrical conductivity of alkali ion conducting Na2CO3 and Na2SO4, were improved by adding alkaline earth carbonates and sulfates, respectively, as well as insulating materials like ¿-Al2O3. The admixing of divalent compounds causes two effects. First a more or less extended solution can exist depending on the radius of the alkaline earth ion and is accompanied by an increase in electrical conductivity. Secondly, a phase mixture with an excess of dopant was observed that shows an enhancement in conductivity and mechanical stability. This phenomenon known as composite effect was observed in the following systems: Na2CO3-BaCO3, Na2CO3-SrCO3, Na2SO4-BaSO4, Na2SO4-¿-Al2O3
On the variable-charged black holes embedded into de Sitter space: Hawking's radiation
In this paper we study the Hawking evaporation of masses of variable-charged
Reissner-Nordstrom and Kerr-Newman, black holes embedded into the de Sitter
universe by considering the charge to be function of radial coordinate of the
spherically symmetric metric.Comment: LaTex, p. 2
On the Creation of the Universe out of Nothing
We explain how the Universe was created with no expenditure of energy or
initial mass.Comment: To be presented at IWARA 2009 (4th International Workshop on
Astronomy and Relativistic Astrophysics), to be held in Brazil, October 200
Post-Newtonian expansion for Gauss-Bonnet Gravity
The Parametrized Post-Newtonian expansion of gravitational theories with a
scalar field coupled to the Gauss-Bonnet invariant is performed and
confrontation of such theories with Solar system experiments is discussed.Comment: 4 pages; typos corrected, published versio
Brazilian Companies and the Grade of Investment
This study is featured in the context of applied typology, of descriptive goal with bibliographic outlining, in the extent of the issue it is features as quantitative, comprising the population of 70 Brazilian corporations recognized by the International certifying agents Standard & Poor’s, Moody’s and Fitch Ratings, which held the corporate investment grade in the year of 2012. Regarding the goal, the scope of this study was the development of an economic and financial indicator aiming to delimit the investment grade that companies present in their corporate structures, through a set of economic and financial indexes linked to liquidity, profitability, debt, and yield, from economic and financial demonstrations of the corporations studied.. The conclusions of the study were based in the results presented by the evolution of the statistical treatment, which were shown to be consistent for the model developed. The reliability of the model of corporate investment grade from the factorial analysis was testified by the Cronbach’s Alpha coefficient that presented value of 0.768, therefore indicating satisfactory consistence to the study
Phase Transition in Conformally Induced Gravity with Torsion
We have considered the quantum behavior of a conformally induced gravity in
the minimal Riemann-Cartan space. The regularized one-loop effective potential
considering the quantum fluctuations of the dilaton and the torsion fields in
the Coleman-Weinberg sector gives a sensible phase transition for an
inflationary phase in De Sitter space. For this effective potential, we have
analyzed the semi-classical equation of motion of the dilaton field in the
slow-rolling regime.Comment: 7pages, no figur
Geometry and Destiny
The recognition that the cosmological constant may be non-zero forces us to
re-evaluate standard notions about the connection between geometry and the fate
of our Universe. An open Universe can recollapse, and a closed Universe can
expand forever. As a corollary, we point out that there is no set of
cosmological observations we can perform that will unambiguously allow us to
determine what the ultimate destiny of the Universe will be.Comment: 7 pages, Gravity Research Foundation Essa
Inflation without Slow Roll
We draw attention to the possibility that inflation (i.e. accelerated
expansion) might continue after the end of slow roll, during a period of fast
oscillations of the inflaton field \phi . This phenomenon takes place when a
mild non-convexity inequality is satisfied by the potential V(\phi). The
presence of such a period of \phi-oscillation-driven inflation can
substantially modify reheating scenarios.
In some models the effect of these fast oscillations might be imprinted on
the primordial perturbation spectrum at cosmological scales.Comment: 9 pages, Revtex, psfig, 1 figure, minor modifications, references
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