A PESQUISA QUALITATIVA: SISTEMATIZAÇÃO DE TEMAS GERADORES E TÉCNICAS DE GRUPO

This study describes the systematization of generating themes into social representations, followed by group works with interventions that go through the stages of identification, domestication, relearning and performance redefinitions.O estudo descreve a sistematização de temas geradores em representações sociais, seguidas de trabalho em grupo com intervenções que passam pelos estágios da identificação, da domesticidade, da reaprendizagem e da redefinição de papéis

A EDUCAÇÃO PARA A SAÚDE: O CLIENTE COMO SUJEITO DA AÇÃO

The author make some considerations on the education for health based on the health-illness process view-point, where the significance of education is different in the traditional education and in the historical materialism context.A autora apresenta algumas considerações sobre a educação para a saúde na perspectiva do processo saúde doença onde o significado de educar é diferente na educação tradicional e no contexto do materialismo histórico

Discovery of a new M32-like "Compact Elliptical" galaxy in the halo of the Abell 496 cD galaxy

Aims: ``Compact ellipticals'' are so rare that a search for M32 analogs is needed to ensure the very existence of this class. Methods: We report here the discovery of A496cE, a M32 twin in the cluster Abell 496, located in the halo of the central cD. Results: Based on CFHT and HST imaging we show that the light profile of A496cE requires a two component fit: a Sersic bulge and an exponential disc. The spectrum of A496cE obtained with the ESO-VLT FLAMES/Giraffe spectrograph can be fit by a stellar synthesis spectrum dominated by old stars, with high values of [Mg/Fe] and velocity dispersion. Conclusions: The capture of A496cE by the cD galaxy and tidal stripping of most of its disc are briefly discussed.Comment: 4 pages, 4 figures, accepted for publication in A&A Letter

A search for faint low surface brightness galaxies in the relaxed cluster Abell 496

Cluster faint low surface brightness galaxies (fLSBs) are difficult to observe. Consequently, their origin, physical properties and number density are not well known. After a first search for fLSBs in the highly substructured Coma cluster, we present here a search for fLSBs in Abell 496. This cluster appears to be much more relaxed than Coma, but is embedded in a large scale filament of galaxies. Our aim is to compare the properties of fLSBs in these two very different clusters, to search for environmental effects. Based on deep CFHT/Megacam images in the u*, g', r' and i' bands, we selected galaxies with r'>21 and surface brightness > 24 mag/arcsec-2. We estimated photometric redshifts for all these galaxies and kept the 142 fLSBs with photo-z<0.2. In a g'-i' versus i' color-magnitude diagram, we find that a large part of these fLSBs follow the red sequence (RS) of brighter galaxies. The fLSBs within +-1sigma of the RS show a homogeneous spatial distribution, while those above the RS appear to be concentrated along the large scale filament of galaxies. These properties are interpreted as agreeing with the idea that RS fLSBs are formed in groups prior to cluster assembly. The formation of red fLSBs could be related to infalling galaxies.Comment: Accepted for publication in A&

The dynamical state of Abell 2399: a bullet-like cluster

While there are many ways to identify substructures in galaxy clusters using different wavelengths, each technique has its own caveat. In this paper, we conduct a detailed substructure search and dynamical state characterisation of Abell 2399, a galaxy cluster in the local Universe ($z \sim 0.0579$), by performing a multi-wavelength analysis and testing the results through hydro-dynamical simulations. In particular, we apply a Gaussian Mixture Model to the spectroscopic data from SDSS, WINGS, and Omega WINGS Surveys to identify substructures. We further use public \textit{XMM-Newton} data to investigate the intracluster medium (ICM) thermal properties, creating temperature, metallicity, entropy, and pressure maps. Finally, we run hydro-dynamical simulations to constrain the merger stage of this system. The ICM is very asymmetrical and has regions of temperature and pressure enhancement that evidence a recent merging process. The optical substructure analysis retrieves the two main X-ray concentrations. The temperature, entropy, and pressure are smaller in the secondary clump than in the main clump. On the other hand, its metallicity is considerably higher. This result can be explained by the scenario found by the hydro-dynamical simulations where the secondary clump passed very near to the centre of the main cluster possibly causing the galaxies of that region to release more metals through the increase of ram-pressure stripping.16Comment: 16 pages, 11 figures. Accepted in MNRA

Baryon fractions in clusters of galaxies: evidence against a preheating model for entropy generation

The Millennium Gas project aims to undertake smoothed-particle hydrodynamic resimulations of the Millennium Simulation, providing many hundred massive galaxy clusters for comparison with X-ray surveys (170 clusters with kTsl > 3 keV). This paper looks at the hot gas and stellar fractions of clusters in simulations with different physical heating mechanisms. These fail to reproduce cool-core systems but are successful in matching the hot gas profiles of non-cool-core clusters. Although there is immense scatter in the observational data, the simulated clusters broadly match the integrated gas fractions within r500 . In line with previous work, however, they fare much less well when compared to the stellar fractions, having a dependence on cluster mass that is much weaker than is observed. The evolution with redshift of the hot gas fraction is much larger in the simulation with early preheating than in one with continual feedback; observations favour the latter model. The strong dependence of hot gas fraction on cluster physics limits its use as a probe of cosmological parameters.Comment: 16 pages, 18 figures, 4 tables. Accepted for publication in MNRA

A nonlinear theory of the parallel firehose and gyrothermal instabilities in a weakly collisional plasma

Weakly collisional plasmas dynamically develop pressure anisotropies with respect to the magnetic field. These anisotropies trigger plasma instabilities at scales just above the ion Larmor radius \rho_i and much below the mean free path \lambda_{mfp}. They have growth rates of a fraction of the ion cyclotron frequency - much faster than either the global dynamics or local turbulence. The instabilities dramatically modify the transport properties and, therefore, the macroscopic dynamics of the plasma. Their nonlinear evolution drives pressure anisotropies towards marginal stability, controlled by the plasma beta \beta_i. Here this nonlinear evolution is worked out for the simplest analytically tractable example - the parallel firehose instability. In the nonlinear regime, both analytical theory and the numerical solution predict secular growth of magnetic fluctuations. They develop a k^{-3} spectrum, extending from scales somewhat larger than \rho_i to the maximum scale that grows secularly with time (~t^{1/2}); the relative pressure anisotropy (\pperp-\ppar)/\ppar tends to the marginal value -2/\beta_i. The marginal state is achieved via changes in the magnetic field, not particle scattering. When a parallel ion heat flux is present, the firehose mutates into the new gyrothermal instability (GTI), which continues to exist up to firehose-stable values of pressure anisotropy, which can be positive and are limited by the heat flux. The nonlinear evolution of the GTI also features secular growth of magnetic fluctuations, but the spectrum is eventually dominated by modes around the scale ~\rho_i l_T/\lambda_{mfp}, where l_T is the scale of the parallel temperature variation. Implications for momentum and heat transport are speculated about. This study is motivated by the dynamics of galaxy cluster plasmas.Comment: 34 pages, replaced with the version published in MNRA

Kinematics and Stellar Populations of Low-Luminosity Early-Type Galaxies in the Abell 496 Cluster

The morphology and stellar populations of low-luminosity early-type galaxies in clusters have until now been limited to a few relatively nearby clusters such as Virgo or Fornax. Scenarii for the formation and evolution of dwarf galaxies in clusters are therefore not well constrained. We investigate here the morphology and stellar populations of low-luminosity galaxies in the relaxed cluster Abell 496 (z=0.0330). Deep multiband imaging obtained with the CFHT Megacam allowed us to select a sample of faint galaxies (-18.8<M_B<-15.1 mag). We observed 118 galaxies spectroscopically with the ESO VLT FLAMES/Giraffe spectrograph (R=6300). We present structural analysis and colour maps for the 48 galaxies belonging to the cluster. We fit the spectra of 46 objects with PEGASE.HR synthetic spectra to estimate the ages, metallicities, and velocity dispersions. We computed values of $\alpha$/Fe abundance ratios from the measurements of Lick indices. High-precision estimates of stellar population properties have been obtained for a large sample of faint galaxies in a cluster, allowing for the extension of relations between stellar populations and internal kinematics to the low-velocity dispersion regime. We have revealed a peculiar population of elliptical galaxies in the core of the cluster, resembling massive early-type galaxies by their stellar population properties and velocity dispersions, but having luminosities of about 2 mag fainter. External mechanisms of gas removal (ram pressure stripping and gravitational harassment) are more likely to have occurred than internal mechanisms such as supernova-driven winds. The violent tidal stripping of intermediate-luminosity, early-type galaxies in the cluster core can explain the properties of the peculiar elliptical galaxies surrounding the cD galaxy.Comment: Accepted to A&A, 48 pages, 62 figures, 3 tables. This version contains low-resolution figures. We encourage you to get the full-resolution PDF (16Mb) from http://voplus.obspm.fr/DataCollections/Abell0496