1,185 research outputs found

    Perfil socioeconômico: sua funcionalidade para o processo investigativo do(a) Assistente Social

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    O trabalho aborda a importância do perfil socioeconômico para o processo investigativo do (a) Assistente Social. O profissional de Serviço Social deve imprimir em sua intervenção uma direção, sendo necessário, para isto, conhecer e problematizar o objeto de sua ação profissional, construindo sua visibilidade a partir de informações e análises consistentes – atitude investigativa. De acordo com Fraga (2010), o trabalho do assistente social deverá ser norteado por um plano de intervenção profissional objetivando construir estratégias coletivas para o enfrentamento das diferentes manifestações de desigualdades e injustiças sociais, numa perspectiva histórica que apreenda o movimento contraditório do real. Neste contexto, o levantamento do perfil socioeconômico é um dos instrumentos necessário no processo investigativo, pois as crescentes demandas de proteção social são postas não apenas por “pobres” ou “desempregados”, mas por uma maioria de cidadãos, que se percebem ameaçados pelos riscos de perderem a segurança advinda de seu trabalho assalariado. Nesta direção, as análises e pesquisas do Serviço Social precisam ser realizadas a partir de situações concretas e possuir utilidade social, não interessando o conhecimento realizado apenas com a finalidade descritiva e contemplativa. Assim, o objetivo deste trabalho é refletir sobre a importância do perfil socioeconômico como estratégia de investigação e intervenção do (a) Assistente Social nas diferentes expressões da “questão social”

    Charging axisymmetric space-times with cosmological constant

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    Ernst's solution generating technique for adding electromagnetic charge to axisymmetric space-times in general relativity is generalised in presence of the cosmological constant. Ernst equations for complex potentials are found and they are traced back to an affective dual complex dynamical system, whose symmetries are studied. In particular this method is able to generate charged, asymptotically (A)dS black holes from their uncharged version: as an example, it is shown explicitly how to pass from the Kerr-(A)dS to the Kerr-Newman-(A)dS metric. A new solution describing a magnetic universe in presence of the cosmological constant is also generated.Comment: 15 pages, v2: typos correcte

    Ice XII in its second regime of metastability

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    We present neutron powder diffraction results which give unambiguous evidence for the formation of the recently identified new crystalline ice phase[Lobban et al.,Nature, 391, 268, (1998)], labeled ice XII, at completely different conditions. Ice XII is produced here by compressing hexagonal ice I_h at T = 77, 100, 140 and 160 K up to 1.8 GPa. It can be maintained at ambient pressure in the temperature range 1.5 < T < 135 K. High resolution diffraction is carried out at T = 1.5 K and ambient pressure on ice XII and accurate structural properties are obtained from Rietveld refinement. At T = 140 and 160 K additionally ice III/IX is formed. The increasing amount of ice III/IX with increasing temperature gives an upper limit of T ~ 150 K for the successful formation of ice XII with the presented procedure.Comment: 3 Pages of RevTeX, 3 tables, 3 figures (submitted to Physical Review Letters

    Pressure-induced amorphization and polyamorphism in one-dimensional single crystal TiO2 nanomaterials

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    The structural phase transitions of single crystal TiO2-B nanoribbons were investigated in-situ at high-pressure using the synchrotron X-ray diffraction and the Raman scattering. Our results have shown a pressure-induced amorphization (PIA) occurred in TiO2-B nanoribbons upon compression, resulting in a high density amorphous (HDA) form related to the baddeleyite structure. Upon decompression, the HDA form transforms to a low density amorphous (LDA) form while the samples still maintain their pristine nanoribbon shape. HRTEM imaging reveals that the LDA phase has an {\alpha}-PbO2 structure with short range order. We propose a homogeneous nucleation mechanism to explain the pressure-induced amorphous phase transitions in the TiO2-B nanoribbons. Our study demonstrates for the first time that PIA and polyamorphism occurred in the one-dimensional (1D) TiO2 nanomaterials and provides a new method for preparing 1D amorphous nanomaterials from crystalline nanomaterials.Comment: 4 figure

    Puzzles in BB physics

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    I discuss some puzzles observed in exclusive BB meson decays, concentrating on the large difference between the direct CP asymmetries in the B0πK±B^0\to \pi^\mp K^\pm and B±π0K±B^\pm\to \pi^0 K^\pm modes, the large B0π0π0B^0\to\pi^0\pi^0 branching ratio, and the large deviation of the mixing-induced CP asymmetries in the bsqqˉb\to sq\bar q penguins from those in the bccˉsb\to c\bar c s trees.Comment: 6 pages, 1 figure, talk presented at the 9th Workshop on High Energy Physics Phenomenology, Bhubaneswar, Orissa, India, Jan. 3-14, 2006; reference adde

    The Ultimate Fate of Supercooled Liquids

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    In recent years it has become widely accepted that a dynamical length scale {\xi}_{\alpha} plays an important role in supercooled liquids near the glass transition. We examine the implications of the interplay between the growing {\xi}_{\alpha} and the size of the crystal nucleus, {\xi}_M, which shrinks on cooling. We argue that at low temperatures where {\xi}_{\alpha} > {\xi}_M a new crystallization mechanism emerges enabling rapid development of a large scale web of sparsely connected crystallinity. Though we predict this web percolates the system at too low a temperature to be easily seen in the laboratory, there are noticeable residual effects near the glass transition that can account for several previously observed unexplained phenomena of deeply supercooled liquids including Fischer clusters, and anomalous crystal growth near T_g

    Does the generalized second law hold in the form of time derivative expression?

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    We investigate whether the generalized second law is valid, using two dimensional black hole spacetime, irrespective of models. A time derivative form of the generalized second law is formulated and it is shown that the law might become invalid. The way to resolve this difficulty is also presented and discussed.Comment: 12 pages, 3 figures, revte

    Coiling Instabilities in Multilamellar Tubes

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    Myelin figures are densely packed stacks of coaxial cylindrical bilayers that are unstable to the formation of coils or double helices. These myelin figures appear to have no intrinsic chirality. We show that such cylindrical membrane stacks can develop an instability when they acquire a spontaneous curvature or when the equilibrium distance between membranes is decreased. This instability breaks the chiral symmetry of the stack and may result in coiling. A unilamellar cylindrical vesicle, on the other hand, will develop an axisymmetric instability, possibly related to the pearling instability.Comment: 6 pages, 2 figure

    Vacuum effects in an asymptotically uniformly accelerated frame with a constant magnetic field

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    In the present article we solve the Dirac-Pauli and Klein Gordon equations in an asymptotically uniformly accelerated frame when a constant magnetic field is present. We compute, via the Bogoliubov coefficients, the density of scalar and spin 1/2 particles created. We discuss the role played by the magnetic field and the thermal character of the spectrum.Comment: 17 pages. RevTe
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