Evolução e fatores de concentração do setor bancário brasileiro a partir de 1994

Os principais resultados dessa pesquisa se deram pela conclusão de que o mercado bancário brasileiro sofreu um choque a partir do plano real e a partir dele o mercado sofreu uma reorganização promovida por planos como Proer e Proes que, por um lado possibilitaram uma consolidação desse mercado e por outro lado promoveram a concentração bancária. Além desses planos, outros fatores que influenciaram na estrutura do mercado se deram por meio da abertura do setor aos bancos estrangeiros e a evolução das exigências regulatórias a partir do acordo de Basiléia II. Com a consolidação do mercado bancário foi possível criar um ambiente mais propício ao crédito e ao mesmo tempo promover uma competição pela concessão do mesmo que se deram, porém, com uma estrutura de elevados spreads

XMM-Newton observations of the Coma cluster relic 1253+275

Using XMM Newton data, we investigate the nature of the X-ray emission in the radio relic 1253+275 in the Coma cluster. We determine the conditions of the cluster gas to check current models of relic formation, and we set constraints on the intracluster magnetic field. Both imaging and spectral analysis are performed, and the X-ray emission is compared with the radio emission. We found that the emission is of thermal origin and is connected to the sub-group around NGC 4839. The best-fit gas temperature in the region of the relic and in its vicinity is in the range 2.8 - 4.0 keV, comparable to the temperature of the NGC 4839 sub-group. We do not detect any high temperature gas, resulting from a possible shock in the region of the Coma relic. We therefore suggest that the main source of energy for particles radiating in the radio relic is likely to be turbulence. From the X-ray data, we can also set a flux upper limit of 3.2 x 10e-13 erg/cm^2 s, in the 0.3 - 10 keV energy range, to the non-thermal emission in the relic region. This leads to a magnetic field B > 1.05 microG.Comment: 4 pages, 2 figures, Accepted for publication in A&A Letter

The distant galaxy cluster CL0016+16: X-ray analysis up to R200R_{200}

To study the mass distribution of galaxy clusters up to their Virial radius, CL0016+16 seems to be a good candidate,since it is a bright massive cluster, previously considered as being dynamically relaxed. Using XMM-Newton observations of CL0016+16, we performed a careful X-ray background analysis, and we detected convincingly its X-ray emission up to $R_{200}$. We then studied its dynamical state with a detailed 2D temperature and surface brightness analysis of the inner part of the cluster. Using the assumption of both spherical symmetry and hydrostatic equilibrium (HE) we can determine the main cluster parameters: total mass, temperature profile, surface brightness profile and $\beta$-parameter. We also build a temperature map which clearly exhibits departure from spherical symmetry in the centre. To estimate the influence of these perturbations onto our total mass estimate, we also compute the total mass in the framework of the HE approach, but this time with various temperature profiles obtained in different directions. These various total mass estimates are consistent with each other. The temperature perturbations are clear signatures of ongoing merger activity. We also find significant residuals after subtracting the emissivity map by a 2D $\beta$-model fit. We conclude that, although CL0016+16 shows clear signs of merger activity and departure from spherical symmetry in the centre, its X-ray emissivity can be detected up to $R_{200}$ and the corresponding mass $M_{200}$ can be computed directly. It is therefore a good candidate to study cosmological scaling laws as predicted by the theory.Comment: 11 pages, 17 figures, Accepted for publication in A&

Measuring Cluster Temperature Profiles with XMM/EPIC

Using the PV observation of A1795, we illustrate the capability of XMM-EPIC to measure cluster temperature profiles, a key ingredient for the determination of cluster mass profiles through the equation of hydrostatic equilibrium. We develop a methodology for spatially resolved spectroscopy of extended sources, adapted to XMM background and vignetting characteristics. The effect of the particle induced background is discussed. A simple unbiased method is proposed to correct for vignetting effects, in which every photon is weighted according to its energy and location on the detector. We were able to derive the temperature profile of A1795 up to 0.4 times the virial radius. A significant and spatially resolved drop in temperature towards the center (r<200 kpc) is observed, which corresponds to the cooling flow region of the cluster. Beyond that region, the temperature is constant with no indication of a fall-off at large radii out to 1.2 Mpc.Comment: 7 pages, 8 figures, Accepted for publication in A&A (special Letter issue on XMM

Spatially resolved X-ray spectroscopy and modeling of the nonthermal emission of the PWN in G0.9+0.1

We performed a spatially resolved spectral X-ray study of the pulsar wind nebula (PWN) in the supernova remnant G0.9+0.1. Furthermore we modeled its nonthermal emission in the X-ray and very high energy (VHE, E > 100 GeV) gamma-ray regime. Using Chandra ACIS-S3 data, we investigated the east-west dependence of the spectral properties of G0.9+0.1 by calculating hardness ratios. We analyzed the EPIC-MOS and EPIC-pn data of two on-axis observations of the XMM-Newton telescope and extracted spectra of four annulus-shaped regions, centered on the region of brightest emission of the source. A radially symmetric leptonic model was applied in order to reproduce the observed X-ray emission of the inner part of the PWN. Using the optimized model parameter values obtained from the X-ray analysis, we then compared the modeled inverse Compton (IC) radiation with the published H.E.S.S. gamma-ray data. The spectral index within the four annuli increases with growing distance to the pulsar, whereas the surface brightness drops. With the adopted model we are able to reproduce the characteristics of the X-ray spectra. The model results for the VHE gamma radiation, however, strongly deviate from the H.E.S.S. data.Comment: 8 pages, 7 figures, accepted for publication in Astronomy & Astrophysic

Unsaturated glycerophospholipids mediate heme crystallization: biological implications for hemozoin formation in the kissing bug Rhodnius prolixus

Hemozoin (Hz) is a heme crystal produced by some blood-feeding organisms, as an efficient way to detoxify heme derived from hemoglobin digestion. In the triatomine insect Rhodnius prolixus , Hz is essentially produced by midgut extracellular phospholipid membranes known as perimicrovillar membranes (PMVM). Here, we investigated the role of commercial glycerophospholipids containing serine, choline and ethanolamine as headgroups and R. prolixus midgut lipids (RML) in heme crystallization. All commercial unsaturated forms of phospholipids, as well as RML, mediated fast and efficient β-hematin formation by means of two kinetically distinct mechanisms: an early and fast component, followed by a late and slow one. The fastest reactions observed were induced by unsaturated forms of phosphatidylethanolamine (uPE) and phosphatidylcholine (uPC), with half-lives of 0.04 and 0.7 minutes, respectively. β-hematin crystal morphologies were strikingly distinct among groups, with uPE producing homogeneous regular brick-shaped crystals. Interestingly, uPC-mediated reactions resulted in two morphologically distinct crystal populations: one less representative group of regular crystals, resembling those induced by uPE, and the other largely represented by crystals with numerous sharp edges and tapered ends. Heme crystallization reactions induced by RML were efficient, with a heme to β-hematin conversion rate higher than 70%, but clearly slower (t1/2 of 9.9-17.7 minutes) than those induced by uPC and uPE. Interestingly, crystals produced by RML were homogeneous in shape and quite similar to those mediated by uPE. Thus, β-hematin formation can be rapidly and efficiently induced by unsaturated glycerophospholipids, particularly uPE and uPC, and may play a role on biological heme crystallization in R. prolixus midgut

The XMM-Newton Ω\Omega Project

The abundance of high-redshift galaxy clusters depends sensitively on the matter density \OmM and, to a lesser extent, on the cosmological constant $\Lambda$. Measurements of this abundance therefore constrain these fundamental cosmological parameters, and in a manner independent and complementary to other methods, such as observations of the cosmic microwave background and distance measurements. Cluster abundance is best measured by the X-ray temperature function, as opposed to luminosity, because temperature and mass are tightly correlated, as demonstrated by numerical simulations. Taking advantage of the sensitivity of XMM-Newton, our Guaranteed Time program aims at measuring the temperature of the highest redshift (z>0.4) SHARC clusters, with the ultimate goal of constraining both \OmM and $\Lambda$.Comment: To appear in the Proceedings of the XXI Moriond Conference: Galaxy Clusters and the High Redshift Universe Observed in X-rays, edited by D. Neumann, F. Durret, & J. Tran Thanh Va