908 resultados para Actor-network Theory
Resumo:
Peer support interventions for people with cancer, their families, and friends have been widely used throughout the world. The present study reviewed the research literature on psychosocial oncology over the past decade to assess the prevalence and contribution of articles on peer support. Using CD-Rom databases, 25 articles were retrieved for review. In each article, patients or their family members were the target group for supportive interventions, which were primarily for the delivery of peer support and included either a qualitative or quantitative evaluation of the program. A definitional taxonomy for peer support interventions, which identified eight discrete settings, was derived from three key dimensions: style of supervision, interpersonal context, and mode of delivery. The studies suggested that peer support programs help by providing emotional and informational support from the perspective of shared personal experience. However, a paucity of research-particularly randomized controlled trials-was noted. The reasons may include inherent difficulties in isolating for study what is essentially a naturalistically occurring interpersonal dynamic from the complex social and community contexts from which it emanates. The authors discuss the gap between practice and theory in this area and recommend a broader and more inclusive view of supportive care for people with cancer. (C) 2003 by The Haworth Press, Inc. All rights reserved.
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This paper reports a study that explored a new construct: climate of fear. We hypothesised that climate of fear would vary across work sites within organisations, but not across organisations. This is in contrast a to measures of organisational culture, which were expected to vary both within and across organisations. To test our hypotheses, we developed a new 13-item measure of perceived fear in organisations and tested it in 20 sites across two organisations (N = 209). Culture variables measured were innovative leadership culture, and communication culture. Results were that climate of fear did vary across sites in both organisations, while differences across organisations were not significant, as we anticipated. Organisational culture, however, varied between the organisations, and within one of the organisations. The climate of fear scale exhibited acceptable psychometric properties.
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Insulin stimulates glucose transport in fat and muscle cells by triggering exocytosis of the glucose transporter GLUT4. To define the intracellular trafficking of GLUT4, we have studied the internalization of an epitope-tagged version of GLUT4 from the cell surface. GLUT4 rapidly traversed the endosomal system en route to a perinuclear location. This perinuclear GLUT4 compartment did not colocalize with endosomal markers (endosomal antigen I protein, transferrin) or TGN38, but showed significant overlap with the TGN target (t)-soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) Syntaxins 6 and 16. These results were confirmed by vesicle immunoisolation. Consistent with a role for Syntaxins 6 and 16 in GLUT4 trafficking we found that their expression was up-regulated significantly during adipocyte differentiation and insulin stimulated their movement to the cell surface. GLUT4 trafficking between endosomes and trans-Golgi network was regulated via an acidic targeting motif in the carboxy terminus of GLUT4, because a mutant lacking this motif was retained in endosomes. We conclude that GLUT4 is rapidly transported from the cell surface to a subdomain of the trans-Golgi network that is enriched in the t-SNAREs Syntaxins 6 and 16 and that an acidic targeting motif in the C-terminal tail of GLUT4 plays an important role in this process.
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The GRIP domain is a targeting sequence found in a family of coiled-coil peripheral Golgi proteins. Previously we demonstrated that the GRIP domain of p230/golgin245 is specifically recruited to tubulovesicular structures of the traps-Golgi network (TGN). Here we have characterized two novel Golgi proteins with functional GRIP domains, designated GCC88 and GCC185. GCC88 cDNA encodes a protein of 88 kDa, and GCC185 cDNA encodes a protein of 185 kDa. Both molecules are brefeldin A-sensitive peripheral membrane proteins and are predicted to have extensive coiled-coil regions with the GRIP domain at the C terminus. By immunofluorescence and immunoelectron microscopy GCC88 and GCC185, and the GRIP protein golgin97, are all localized to the TGN of Hela cells. Overexpression of full-length GCC88 leads to the formation of large electron dense structures that extend from the traps-Golgi. These de novo structures contain GCC88 and co-stain for the TGN markers syntaxin 6 and TGN38 but not for alpha2,6-sialyltransferase, beta-COP, or cis-Golgi GM130. The formation of these abnormal structures requires the N-terminal domain of GCC88. TGN38, which recycles between the TGN and plasma membrane, was transported into and out of the GCC88 decorated structures. These data introduce two new GRIP domain proteins and implicate a role for GCC88 in the organization of a specific TGN subcompartment involved with membrane transport.
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Galpha interacting protein (GAIP) is a regulator of G protein signaling protein that associates dynamically with vesicles and has been implicated in membrane trafficking, although its specific role is not yet known. Using an in vitro budding assay, we show that GAIP is recruited to a specific population of trans-Golgi network-derived vesicles and that these are distinct from coatomer or clathrin-coated vesicles. A truncation mutant (NT-GAIP) encoding only the N-terminal half of GAIP is recruited to trans -Golgi network membranes during the formation of vesicle carriers. Overexpression of NT-GAIP induces the formation of long, coated tubules, which are stabilized by microtubules. Results from the budding assay and from imaging in live cells show that these tubules remain attached to the Golgi stack rather than being released as carrier vesicles. NT-GAIP expression blocks membrane budding and results in the accumulation of tubular carrier intermediates. NT-GAIP-decorated tubules are competent to load vesicular stomatitis virus protein G-green fluorescent protein as post-Golgi, exocytic cargo and in cells expressing NT-GAIP there is reduced surface delivery of vesicular stomatitis virus protein G-green fluorescent protein. We conclude that GAIP functions as an essential part of the membrane budding machinery for a subset of post-Golgi exocytic carriers derived from the trans-Golgi network.
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This paper conducts a dynamic stability analysis of symmetrically laminated FGM rectangular plates with general out-of-plane supporting conditions, subjected to a uniaxial periodic in-plane load and undergoing uniform temperature change. Theoretical formulations are based on Reddy's third-order shear deformation plate theory, and account for the temperature dependence of material properties. A semi-analytical Galerkin-differential quadrature approach is employed to convert the governing equations into a linear system of Mathieu-Hill equations from which the boundary points on the unstable regions are determined by Bolotin's method. Free vibration and bifurcation buckling are also discussed as subset problems. Numerical results are presented in both dimensionless tabular and graphical forms for laminated plates with FGM layers made of silicon nitride and stainless steel. The influences of various parameters such as material composition, layer thickness ratio, temperature change, static load level, boundary constraints on the dynamic stability, buckling and vibration frequencies are examined in detail through parametric studies.
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This paper is concerned with evaluating the performance of loss networks. Accurate determination of loss network performance can assist in the design and dimen- sioning of telecommunications networks. However, exact determination can be difficult and generally cannot be done in reasonable time. For these reasons there is much interest in developing fast and accurate approximations. We develop a reduced load approximation that improves on the famous Erlang fixed point approximation (EFPA) in a variety of circumstances. We illustrate our results with reference to a range of networks for which the EFPA may be expected to perform badly.
Resumo:
A new questionnaire, the Maternal Mental State Input Inventory (MMSII) was created to measure mothers' preferences for introducing and elaborating on mental states in conversation with their young children. In two studies, the questionnaire was given to mothers of young children, and the children's theory of mind (ToM) development was assessed with standard tasks. In both studies, the questionnaire exhibited good internal reliability, and significant correlations emerged between mothers' self-reported preferences for elaborated, explanatory talk about the mental states and children's theory of mind performance. Further, mothers' conversational preferences, as measured by the MMSII, were the best predictors of children's theory of mind development when relevant control variables were included in the analyses. These results converge with naturalistic observational research that has demonstrated links between mothers' conversational styles and their children's theory of mind. They go further in suggesting that mothers' tendencies toward elaborated, explanatory talk about a range of mental states is particularly beneficial to children's theory of mind development. (C) 2003 Elsevier Inc. All rights reserved.
Resumo:
This paper presents a new model based on thermodynamic and molecular interaction between molecules to describe the vapour-liquid phase equilibria and surface tension of pure component. The model assumes that the bulk fluid can be characterised as set of parallel layers. Because of this molecular structure, we coin the model as the molecular layer structure theory (MLST). Each layer has two energetic components. One is the interaction energy of one molecule of that layer with all surrounding layers. The other component is the intra-layer Helmholtz free energy, which accounts for the internal energy and the entropy of that layer. The equilibrium between two separating phases is derived from the minimum of the grand potential, and the surface tension is calculated as the excess of the Helmholtz energy of the system. We test this model with a number of components, argon, krypton, ethane, n-butane, iso-butane, ethylene and sulphur hexafluoride, and the results are very satisfactory. (C) 2002 Elsevier Science B.V. All rights reserved.
Resumo:
We present the quantum theory of the far-off-resonance continuous-wave Raman laser using the Heisenberg-Langevin approach. We show that the simplified quantum Langevin equations for this system are mathematically identical to those of the nondegenerate optical parametric oscillator in the time domain with the following associations: pump pump, Stokes signal, and Raman coherence idler. We derive analytical results for both the steady-state behavior and the time-dependent noise spectra, using standard linearization procedures. In the semiclassical limit, these results match with previous purely semiclassical treatments, which yield excellent agreement with experimental observations. The analytical time-dependent results predict perfect photon statistics conversion from the pump to the Stokes and nonclassical behavior under certain operational conditions.
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We present a theory for the transport of molecules adsorbed in slit and cylindrical nanopores at low density, considering the axial momentum gain of molecules oscillating between diffuse wall reflections. Good agreement with molecular dynamics simulations is obtained over a wide range of pore sizes, including the regime of single-file diffusion where fluid-fluid interactions are shown to have a negligible effect on the collective transport coefficient. We show that dispersive fluid-wall interactions considerably attenuate transport compared to classical hard sphere theory.
Resumo:
Esta pesquisa teve como objetivo geral compreender a proposta/ prática curricular do Atendimento Educacional Especializado (AEE) na Sala de Recursos Multifuncionais (SRM) enquanto função complementar na educação da criança pequena com deficiência e Transtornos Globais do Desenvolvimento (TGD). Partimos das constatações de que, nas duas últimas décadas, documentos oficiais, assim como pesquisas na área, apontam a necessidade de um trabalho pedagógico inclusivo, que atenda às demandas e características dos diferentes sujeitos matriculados. Questionamos se a proposta e prática curricular complementar do AEE, por meio da SRM, têm contribuído para a inclusão da criança pequena, público alvo da educação especial, nas práticas pedagógicas da sala de aula comum? Teoricamente buscamos as contribuições da Abordagem Histórico-Cultural para compreender o desenvolvimento e aprendizagem da criança com deficiência, assim como procuramos a interlocução com os teóricos do currículo, entre os quais Sacristán. Como metodologia, utilizamos a pesquisa-ação colaborativo-crítico. O lócus da pesquisa foi um Centro de Educação Infantil, situado em Vitória/ES, com uma sala de recurso multifuncional, modelo proposto pelo Ministério da Educação (MEC). Os sujeitos participantes foram crianças de 3 a 7 anos matriculadas no Centro Municipal de Educação Infantil (CMEI) e encaminhadas para o AEE, na SRM (seis crianças surdas, sete crianças com manifestações de TGD e uma criança com Síndrome de Down); dois professores de educação especial da SRM (uma professora da área da área de Deficiência Intelectual (DI), uma professora bilíngue e um instrutor surdo); professores regentes do turno da manhã CMEI e dois pedagogos. Como perspectiva teórico-metodológica, optamos pela rede significações (Rossetti-Ferreira, 2004) que tem seus pressupostos fundamentados na teoria histórico-cultural, que compreende os processos de desenvolvimento humano como atos de significação constituídos por múltiplas interações estabelecidas social e culturalmente pelos sujeitos durante toda a vida. A organização e análise dos dados ocorreram por meio dos movimentos, cenários e atores; as práticas curriculares inclusivas na/da escola: a SRM e a sala de aula comum em seus encontros e desencontros; a preocupação com o desenvolvimento psicomotor da criança; o brincar versus a aquisição da leitura e escrita; o diálogo entre o currículo da SRM e a sala de aula comum e os encontros colaborativos com os professores de educação especial, com as pedagogas e com as professoras regentes do CMEI. Algumas considerações importantes se destacam, entre as quais: a falta de formação e desconhecimento por parte dos professores de educação especial sobre a proposta curricular da educação infantil e práticas pedagógicas descontextualizadas e fragmentadas desenvolvidas na SRM, que dificultam a ação complementar ao trabalho da classe comum. Para as professoras das salas de atividades o AEE é viável na escola de educação infantil, mas não somente na SRM, concordam que deve haver o atendimento educacional especializado no turno em que a criança esteja matriculada; que ele pode ajudar na inclusão da criança público alvo da educação especial, por meio de práticas sociais e culturais lúdicas, linguísticas e intelectuais. Concluímos que as professoras desejam um AEE dinâmico, interlocutor, que se movimente na escola como um todo.