1,043 research outputs found
Closed Spaces in Cosmology
This paper deals with two aspects of relativistic cosmologies with closed
(compact and boundless) spatial sections. These spacetimes are based on the
theory of General Relativity, and admit a foliation into space sections S(t),
which are spacelike hypersurfaces satisfying the postulate of the closure of
space: each S(t) is a 3-dimensional, closed Riemannian manifold. The discussed
topics are: (1) A comparison, previously obtained, between Thurston's
geometries and Bianchi-Kantowski-Sachs metrics for such 3-manifolds is here
clarified and developed. (2) Some implications of global inhomogeneity for
locally homogeneous 3-spaces of constant curvature are analyzed from an
observational viewpoint.Comment: 20 pages, 6 figures, revised version of published paper. In version
2: several misprints corrected, 'redshifting' in figures improved. Version 3:
a few style corrections; couple of paragraphs in subsection 2.4 rewritten.
Version 4: figures 5 and 6 corrrecte
Discussing the Relationship Between Venue and Learning in the Education of Health Professionals
Objectives: To discuss the relationship between the education of health professionals and the off-campus venues where their practicums or internships are served, in order to modify and implement innovations in the curriculum to meet identified needs
Some integrals ocurring in a topology change problem
In a paper presented a few years ago, De Lorenci et al. showed, in the
context of canonical quantum cosmology, a model which allowed space topology
changes (Phys. Rev. D 56, 3329 (1997)). The purpose of this present work is to
go a step further in that model, by performing some calculations only estimated
there for several compact manifolds of constant negative curvature, such as the
Weeks and Thurston spaces and the icosahedral hyperbolic space (Best space).Comment: RevTeX article, 4 pages, 1 figur
QCD traveling waves phenomenology revisited
In this paper we review and update the Amaral-Gay Ducati-Betemps-Soyez
saturation model, by testing it against the recent H1-ZEUS combined data on
deep inelastic scattering, including heavy quarks in the dipole amplitude. We
obtain that this model, which is based on traveling wave solutions of the
Balitsky-Kovchegov equation and built in the momentum space framework, yields
very accurate descriptions of the reduced cross section,
, as well as DIS structure functions such as
and , all measured at HERA. Additionally, it
provides good descriptions of heavy quark structure functions, and
at small- and GeV. We also use the
improved model to make predictions for structure functions to be measured in
the near future at LHeC.Comment: 13 pages, 7 figure
Effects of repeated extracorporeal shock wave on kidney apoptosis of normal and diabetic rat
OBJECTIVE: To assess the effect of repeated extracorporeal shock waves (ESW) on the apoptosis of renal parenchyma in normal and diabetic rats by the caspase-3 expression. MATERIALS AND METHODS: 80 rats were assigned for ESW (Direx Tripter X1® - 14 KVA) to one of three groups with 50% rats with diabetes (A) and 50% normal (B) in each: G1 (n = 40): no ESW; G2 (n = 20): one ESW; G3 (n = 20): two ESWin an interval of 14 days. The animals were sacrificed 3 days after the ESW and samples of the renal parenchyma were histologically prepared, stained by the caspase-3 cleavage immunohistochemical method, and the apoptotic index (ApIn) was calculated by computer program Image Pro-Plus V 4,5,1 Media Cybernetics® ( ApIn = number of apoptotic cells in the microscopic section / total cells in the microscopic section). RESULTS: There was no statistical difference in ApIn of normal rats with one ESW (8.4 + 0.2) or two ESW (9.1 + 0.3) and both were similar to the control group with no ESW (7.9 + 0.2). The ApIn of diabetic rats with one ESW (7.4 + 0.3) was similar to the normal rats with one or two ESW. On the other hand, the ApIn was statistically higher in diabetic rats with two ESW (11.9 + 0.4) than in diabetic rats with one ESW (7.4 + 0.3). CONCLUSIONS: The ApIn of normal rats with a single (2,000 SW) or repeated ESW (4,000 SW) was similar to the control animals without any ESW. In diabetic rats, the repeated ESW (4,000 SW) may result in an additional risk of tissue damage expressed by the higher ApIn.Universidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina (EPM) Department of SurgeryUNIFESP, EPM, Department of SurgerySciEL
A method to search for topological signatures in the angular distribution of cosmic objects
We present a method to search for large angular-scale correlations, termed
topological signatures, in the angular distribution of cosmic objects, which
does not depend on cosmological models or parameters and is based only on the
angular coordinates of the objects. In order to explore Cosmic Microwave
Background temperature fluctuations data, we applied this method to simulated
distributions of objects in thin spherical shells located in three different
multiply-connected Euclidean 3-spaces (, , and ), and found
that the topological signatures due to these topologies can be revealed even if
their intensities are small. We show how to detect such signatures for the
cases of full-sky and partial-sky distributions of objects. This method can
also be applied to other ensembles of cosmic objects, like galaxies or quasars,
in order to reveal possible angular-scale correlations in their distributions.Comment: 11 pages, 18 figures. To appear in A&
Soft diffraction within the QCD color dipole picture
In this work we consider the QCD parton saturation models to describe soft
interactions at the high energy limit. The total and elastic cross sections as
well as the elastic slope parameter are obtained for proton-proton and
pion-proton collisions and compared to recent experimental results. The
analyses are done within the color dipole formalism taking into account
saturation models which have been tested against DIS data. The main point is
that the match between soft and hard interaction occurs in the saturation
region which can be described by high density QCD approaches. Discussion is
performed on the main theoretical uncertainties associated with calculations.Comment: 12 pages, 6 figures. Final version to be published in Physical Review
Fixação biológica de nitrogênio na cultura do arroz irrigado por inundação: Parte I: bactérias endofíticas diazotróficas isoladas das cultivares BRS 7 "Taim" e BRS Pelota.
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