492 research outputs found
BIBLIOTECA COMO ELEMENTO BIOGRÁFICO - CASO MACHADO DE ASSIS
Este artigo visa apreender e interpretar a presença da História na biblioteca e na obra de Machado. Com este objetivo, analiso alguns vestígios procurando perceber qual a importância e qual o significado dessa presença da História para a biografia intelectual de Machado
The Integrated Sachs-Wolfe Effect in Time Varying Vacuum Model
The integrated Sachs-Wolfe (ISW) effect is an important implication for dark
energy. In this paper, we have calculated the power spectrum of the ISW effect
in the time varying vacuum cosmological model, where the model parameter
is obtained by the observational constraint of the growth rate.
It's found that the source of the ISW effect is not only affected by the
different evolutions of the Hubble function and the dimensionless matter
density , but also by the different growth function , all
of which are changed due to the presence of matter production term in the time
varying vacuum model. However, the difference of the ISW effect in
model and model is lessened to
a certain extent due to the integration from the time of last scattering to the
present. It's implied that the observations of the galaxies with high redshift
are required to distinguish the two models
O poder investigatório do Ministério Público
Este trabalho se reserva à análise da legitimidade de realização de investigações criminais
diretamente pelo Ministério Público diante da atual Constituição Federal Brasileira. O tema,
conquanto não esteja definitivamente consolidado em nosso ordenamento jurídico, revela o
entendimento majoritário no sentido de que o Parquet tem legitimidade para realizar
diretamente os atos que compõem uma investigação criminal. Não obstante tal realidade, há
aqueles que defendem a ilegitimidade da instituição para praticar atos investigatórios diante
de uma suposta falta de regulamentação legal para tal. A presente pesquisa visa a expor os
argumentos favoráveis à ideia de que o Ministério Público possui legitimidade para a
realização de diligências investigativas, eis que tal atribuição se apresenta amplamente
legitimada em nosso ordenamento jurídico. A fim de atingir este objetivo, confrontam-se os
argumentos contrários às argumentações aqui expostas
CMB Anisotropy of the Poincare Dodecahedron
We analyse the anisotropy of the cosmic microwave background (CMB) for the
Poincare dodecahedron which is an example for a multi-connected spherical
universe. We compare the temperature correlation function and the angular power
spectrum for the Poincare dodecahedral universe with the first-year WMAP data
and find that this multi-connected universe can explain the surprisingly low
CMB anisotropy on large scales found by WMAP provided that the total energy
density parameter Omega_tot is in the range 1.016...1.020. The ensemble average
over the primordial perturbations is assumed to be the scale-invariant
Harrison-Zel'dovich spectrum. The circles-in-the-sky signature is studied and
it is found that the signal of the six pairs of matched circles could be missed
by current analyses of CMB sky maps
Characterizing Width Uniformity by Wave Propagation
This work describes a novel image analysis approach to characterize the
uniformity of objects in agglomerates by using the propagation of normal
wavefronts. The problem of width uniformity is discussed and its importance for
the characterization of composite structures normally found in physics and
biology highlighted. The methodology involves identifying each cluster (i.e.
connected component) of interest, which can correspond to objects or voids, and
estimating the respective medial axes by using a recently proposed wavefront
propagation approach, which is briefly reviewed. The distance values along such
axes are identified and their mean and standard deviation values obtained. As
illustrated with respect to synthetic and real objects (in vitro cultures of
neuronal cells), the combined use of these two features provide a powerful
description of the uniformity of the separation between the objects, presenting
potential for several applications in material sciences and biology.Comment: 14 pages, 23 figures, 1 table, 1 referenc
Cosmological Black Holes as Seeds of Voids in Galaxy Distribution
Deep surveys indicate a bubbly structure of cosmological large scale which
should be the result of evolution of primordial density perturbations. Several
models have been proposed to explain origin and dynamics of such features but,
till now, no exhaustive and fully consistent theory has been found. We discuss
a model where cosmological black holes, deriving from primordial perturbations,
are the seeds for large-scale-structure voids. We give details of dynamics and
accretion of the system voids-cosmological black holes from the epochs
till now finding that void of of diameter and
under-density of -0.9 will fits the observations without conflicting with the
homogeneity and isotropy of cosmic microwave background radiation.Comment: to appear in Astronomy & Astrophysic
Atividade de invertases e sacarose sintase em plantas de cafeeiro pulverizadas com solução de sacarose
Uma prática cuja eficiência não foi ainda comprovada cientificamente, é a pulverização dos cafeeiros com solução diluída de sacarose, como fonte de carbono para as plantas. Este trabalho visou estudar o efeito da pulverização de açúcar via folha nos teores endógenos de carboidratos e na atividade das enzimas invertases e sacarose sintase em mudas de cafeeiros (Coffea arabica L.) com baixo (baixo) e alto (normal) nível de reservas de carbono. As pulverizações ocorreram nas concentrações de 0,5 e 1% de sacarose utilizando-se água como testemunha. A aplicação de sacarose a 1% aumentou a concentração de açúcares solúveis totais (AST) em plantas depauperadas, como também aumentou as atividades das enzimas invertase ácida da parede, invertase ácida do vacúolo, invertase neutra do citosol e sacarose sintase. Em plantas com níveis normais de carboidratos não foi observada nenhuma alteração nos teores dos AST, como também nas atividades de tais enzimas. Independentemente dos tratamentos aplicados e do estado fisiológico das plantas, não foram observadas diferenças na transpiração e na condutância estomática, mostrando, desta forma, o controle estomático da transpiração. A fotossíntese foi estimulada a 0,5% e 1% em plantas depauperadas, o que não aconteceu com plantas normais. A pulverização de sacarose em mudas de cafeeiros só é eficiente tratando-se de plantas depauperadas na concentração de 1%.One management practice of which the efficiency has not yet been scientifically tested is spraying coffee plants with diluted sucrose solutions as a source of carbon for the plant. This paper evaluates the effect of foliar spraying with sugar on the endogenous level of carbohydrates and on the activities of invertase and sucrose synthase in coffee (Coffea arabica L.) seedlings with reduced (low) and high (normal) levels of carbon reserve. The concentrations used were 0.5 and 1.0% sucrose, and water as a control. The use of sucrose at 1.0% caused an increase in the concentration of total soluble sugars in depauperate plants, as well as increased the activity of the following enzymes: cell wall and vacuole acid invertase, neutral cytosol invertase and sucrose synthase. In plants with high level of carbon reserve, no increments in total soluble sugar levels or in enzymatic activity were observed. Regardless of treatments or plants physiological state, no differences in transpiration or stomatal conductance were observed, demonstrating the stomatal control of transpiration. Photosynthesis was stimulated with the use of 0.5 and 1.0 % sucrose only in depauperate plants. Coffee seedling spraying with sucrose is only efficient for depauperate plants, at the concentration of 1.0%
A Study of the Orbits of the Logarithmic Potential for Galaxies
The logarithmic potential is of great interest and relevance in the study of
the dynamics of galaxies. Some small corrections to the work of Contopoulos &
Seimenis (1990) who used the method of Prendergast (1982) to find periodic
orbits and bifurcations within such a potential are presented. The solution of
the orbital radial equation for the purely radial logarithmic potential is then
considered using the p-ellipse (precessing ellipse) method pioneered by Struck
(2006). This differential orbital equation is a special case of the generalized
Burgers equation. The apsidal angle is also determined, both numerically as
well as analytically by means of the Lambert W and the Polylogarithm functions.
The use of these functions in computing the gravitational lensing produced by
logarithmic potentials is discussed.Comment: 12 pages, 4 figures. Accepted by MNRAS Sept 6 201
Neuroprotective Effect of Transplanted Human Embryonic Stem Cell-Derived Neural Precursors in an Animal Model of Multiple Sclerosis
BACKGROUND: Multiple sclerosis (MS) is an immune mediated demyelinating disease of the central nervous system (CNS). A potential new therapeutic approach for MS is cell transplantation which may promote remyelination and suppress the inflammatory process. METHODS: We transplanted human embryonic stem cells (hESC)-derived early multipotent neural precursors (NPs) into the brain ventricles of mice induced with experimental autoimmune encephalomyelitis (EAE), the animal model of MS. We studied the effect of the transplanted NPs on the functional and pathological manifestations of the disease. RESULTS: Transplanted hESC-derived NPs significantly reduced the clinical signs of EAE. Histological examination showed migration of the transplanted NPs to the host white matter, however, differentiation to mature oligodendrocytes and remyelination were negligible. Time course analysis of the evolution and progression of CNS inflammation and tissue injury showed an attenuation of the inflammatory process in transplanted animals, which was correlated with the reduction of both axonal damage and demyelination. Co-culture experiments showed that hESC-derived NPs inhibited the activation and proliferation of lymph node-derived T cells in response to nonspecific polyclonal stimuli. CONCLUSIONS: The therapeutic effect of transplantation was not related to graft or host remyelination but was mediated by an immunosuppressive neuroprotective mechanism. The attenuation of EAE by hESC-derived NPs, demonstrated here, may serve as the first step towards further developments of hESC for cell therapy in MS
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