Teoria as representações sociais: uma ferramenta para a análise de exposições museológicas

A Teoria das Representações Sociais (TRS) é uma das principais correntes teóricas da Psicologia Social e tem como objecto de estudo a interacção entre o indivíduo e a sociedade na construção da realidade. Partindo do entendimento dos museus como lugares de representação e onde acontece a interacção entre o indivíduo/sociedade com essa parte da realidade que é o património cultural, pretendemos demonstrar a validade da TRS como instrumento ou ferramenta de análise das imagens da Mulher reflectidas em exposições museológicas dos actuais museus portugueses.

While programak: konputagarritasun teoria oinarritzeko tresna

Konputagarritasun Teoriaren asmoa sistema konputazionalen muga teorikoak aztertzea da. Bere helburu nagusia problemak konputagarri eta konputaezinen artean bereiztea da, problema konputagarria ebazpide informatikoa onartzen duenari deitzen diogula kontuan hartuta. Emaitza horiek garatzeko konputagailu eredu abstraktu erabiliena, historikoki, Turing-en Makina izan da. Ingeniaritza Informatikoko ikasleek eredu abstraktuaren eta konputagailu errealen artean distantzia dagoela nabari dezakete, horregatik programaziotik hurbilago dagoen eredu bat erabiltzea egokiagoa da, while programak hain zuzen ere. While programekin Turingen makinekin ebazten diren problema berak ebazten dira. Aldiz, while programak erabiltzen askoz errazagoak dira, batez ere aurretik informatika errealean esperientzia duten pertsonentzat, lengoaia agintzaile klasikoen programen itxura hartzen baitute. Testu honek while programak erabiltzen ditu, behar denean hauek birformulatuz eta beraien abantailak aprobetxatuz, konputazioa sinbolo arbitrarioen manipulazioaren baitan definituta gera dadin. Horrela, errealitate informatikotik askoz hurbilagoa egongo da. While programak zer diren eta nola erabiltzen diren zehaztasunez azaltzen da, eta gainera, beste agindu edo datu-mota batzuk gehitzea zergatik ez den beharrezkoa justifikatzen da.

On the energetics of stratified turbulent mixing, irreversible thermodynamics, Boussinesq models and the ocean heat engine controversy

In this paper, the available potential energy (APE) framework of Winters et al. (J. Fluid Mech., vol. 289, 1995, p. 115) is extended to the fully compressible Navier– Stokes equations, with the aims of clarifying (i) the nature of the energy conversions taking place in turbulent thermally stratified fluids; and (ii) the role of surface buoyancy fluxes in the Munk & Wunsch (Deep-Sea Res., vol. 45, 1998, p. 1977) constraint on the mechanical energy sources of stirring required to maintain diapycnal mixing in the oceans. The new framework reveals that the observed turbulent rate of increase in the background gravitational potential energy GPEr , commonly thought to occur at the expense of the diffusively dissipated APE, actually occurs at the expense of internal energy, as in the laminar case. The APE dissipated by molecular diffusion, on the other hand, is found to be converted into internal energy (IE), similar to the viscously dissipated kinetic energy KE. Turbulent stirring, therefore, does not introduce a new APE/GPEr mechanical-to-mechanical energy conversion, but simply enhances the existing IE/GPEr conversion rate, in addition to enhancing the viscous dissipation and the entropy production rates. This, in turn, implies that molecular diffusion contributes to the dissipation of the available mechanical energy ME =APE +KE, along with viscous dissipation. This result has important implications for the interpretation of the concepts of mixing efficiency γmixing and flux Richardson number Rf , for which new physically based definitions are proposed and contrasted with previous definitions. The new framework allows for a more rigorous and general re-derivation from the first principles of Munk & Wunsch (1998, hereafter MW98)’s constraint, also valid for a non-Boussinesq ocean: G(KE) ≈ 1 − ξ Rf ξ Rf Wr, forcing = 1 + (1 − ξ )γmixing ξ γmixing Wr, forcing , where G(KE) is the work rate done by the mechanical forcing, Wr, forcing is the rate of loss of GPEr due to high-latitude cooling and ξ is a nonlinearity parameter such that ξ =1 for a linear equation of state (as considered by MW98), but ξ <1 otherwise. The most important result is that G(APE), the work rate done by the surface buoyancy fluxes, must be numerically as large as Wr, forcing and, therefore, as important as the mechanical forcing in stirring and driving the oceans. As a consequence, the overall mixing efficiency of the oceans is likely to be larger than the value γmixing =0.2 presently used, thereby possibly eliminating the apparent shortfall in mechanical stirring energy that results from using γmixing =0.2 in the above formula.

Identifying and quantifying nonconservative energy production/destruction terms in hydrostatic Boussinesq primitive equation models

This paper seeks to illustrate the point that physical inconsistencies between thermodynamics and dynamics usually introduce nonconservative production/destruction terms in the local total energy balance equation in numerical ocean general circulation models (OGCMs). Such terms potentially give rise to undesirable forces and/or diabatic terms in the momentum and thermodynamic equations, respectively, which could explain some of the observed errors in simulated ocean currents and water masses. In this paper, a theoretical framework is developed to provide a practical method to determine such nonconservative terms, which is illustrated in the context of a relatively simple form of the hydrostatic Boussinesq primitive equation used in early versions of OGCMs, for which at least four main potential sources of energy nonconservation are identified; they arise from: (1) the “hanging” kinetic energy dissipation term; (2) assuming potential or conservative temperature to be a conservative quantity; (3) the interaction of the Boussinesq approximation with the parameterizations of turbulent mixing of temperature and salinity; (4) some adiabatic compressibility effects due to the Boussinesq approximation. In practice, OGCMs also possess spurious numerical energy sources and sinks, but they are not explicitly addressed here. Apart from (1), the identified nonconservative energy sources/sinks are not sign definite, allowing for possible widespread cancellation when integrated globally. Locally, however, these terms may be of the same order of magnitude as actual energy conversion terms thought to occur in the oceans. Although the actual impact of these nonconservative energy terms on the overall accuracy and physical realism of the oceans is difficult to ascertain, an important issue is whether they could impact on transient simulations, and on the transition toward different circulation regimes associated with a significant reorganization of the different energy reservoirs. Some possible solutions for improvement are examined. It is thus found that the term (2) can be substantially reduced by at least one order of magnitude by using conservative temperature instead of potential temperature. Using the anelastic approximation, however, which was initially thought as a possible way to greatly improve the accuracy of the energy budget, would only marginally reduce the term (4) with no impact on the terms (1), (2) and (3).

Wave-activity conservation laws for the three-dimensional anelastic and Boussinesq equations with a horizontally homogeneous background flow

Wave-activity conservation laws are key to understanding wave propagation in inhomogeneous environments. Their most general formulation follows from the Hamiltonian structure of geophysical fluid dynamics. For large-scale atmospheric dynamics, the Eliassen–Palm wave activity is a well-known example and is central to theoretical analysis. On the mesoscale, while such conservation laws have been worked out in two dimensions, their application to a horizontally homogeneous background flow in three dimensions fails because of a degeneracy created by the absence of a background potential vorticity gradient. Earlier three-dimensional results based on linear WKB theory considered only Doppler-shifted gravity waves, not waves in a stratified shear flow. Consideration of a background flow depending only on altitude is motivated by the parameterization of subgrid-scales in climate models where there is an imposed separation of horizontal length and time scales, but vertical coupling within each column. Here we show how this degeneracy can be overcome and wave-activity conservation laws derived for three-dimensional disturbances to a horizontally homogeneous background flow. Explicit expressions for pseudoenergy and pseudomomentum in the anelastic and Boussinesq models are derived, and it is shown how the previously derived relations for the two-dimensional problem can be treated as a limiting case of the three-dimensional problem. The results also generalize earlier three-dimensional results in that there is no slowly varying WKB-type requirement on the background flow, and the results are extendable to finite amplitude. The relationship A E =cA P between pseudoenergy A E and pseudomomentum A P, where c is the horizontal phase speed in the direction of symmetry associated with A P, has important applications to gravity-wave parameterization and provides a generalized statement of the first Eliassen–Palm theorem.

Available potential energy density for a multicomponent Boussinesq fluid with arbitrary nonlinear equation of state

In this paper, the concept of available potential energy (APE) density is extended to a multicomponent Boussinesq fluid with a nonlinear equation of state. As shown by previous studies, the APE density is naturally interpreted as the work against buoyancy forces that a parcel needs to perform to move from a notional reference position at which its buoyancy vanishes to its actual position; because buoyancy can be defined relative to an arbitrary reference state, so can APE density. The concept of APE density is therefore best viewed as defining a class of locally defined energy quantities, each tied to a different reference state, rather than as a single energy variable. An important result, for which a new proof is given, is that the volume integrated APE density always exceeds Lorenz’s globally defined APE, except when the reference state coincides with Lorenz’s adiabatically re-arranged reference state of minimum potential energy. A parcel reference position is systematically defined as a level of neutral buoyancy (LNB): depending on the nature of the fluid and on how the reference state is defined, a parcel may have one, none, or multiple LNB within the fluid. Multiple LNB are only possible for a multicomponent fluid whose density depends on pressure. When no LNB exists within the fluid, a parcel reference position is assigned at the minimum or maximum geopotential height. The class of APE densities thus defined admits local and global balance equations, which all exhibit a conversion with kinetic energy, a production term by boundary buoyancy fluxes, and a dissipation term by internal diffusive effects. Different reference states alter the partition between APE production and dissipation, but neither affect the net conversion between kinetic energy and APE, nor the difference between APE production and dissipation. We argue that the possibility of constructing APE-like budgets based on reference states other than Lorenz’s reference state is more important than has been previously assumed, and we illustrate the feasibility of doing so in the context of an idealised and realistic oceanic example, using as reference states one with constant density and another one defined as the horizontal mean density field; in the latter case, the resulting APE density is found to be a reasonable approximation of the APE density constructed from Lorenz’s reference state, while being computationally cheaper.

Significado contemporâneo de teoria matemática da comunicação

Passamos por uma transição tecnológica. Quer a chamemos de Revolução Digital, Era da Informação, Sociedade em Rede etc, é inegável que a base de tal transição está na crescente mudança das tecnologias analógicas de comunicação e armazenamento de informação para as tecnologias digitais. Os fundamentos científicos de tal mudança foram estabelecidos em 1948, no livro do matemático e engenheiro americano Claude Elwood Shannon chamado Teoria Matemática da Comunicação. O livro, um clássico das agora convergentes áreas de informática e telecomunicações, definiu uma série de conceitos e modelos que atravessaram as décadas de tecnologia analógica e permanece, em plena era digital, um guia para engenheiros e cientistas que desenvolvem as onipresentes tecnologias de comunicação. Além disso, o corpo teórico presente em Teoria Matemática da Comunicação se espalhou por diversas áreas do conhecimento humano com o nome de Teoria da Informação.

A teoria psicodramática e o desenvolvimento do papel profissional

As intervenções psicodramáticas praticadas em organizações empresariais seguem as sistematizações criadas por Moreno na elaboração do projeto socionômico (sociometria e psicodrama), que reforçam a importância de se trabalhar dentro do campo dos papéis profissionais, pois eles fazem parte do cotidiano das pessoas e, enquanto tal são o lugar da alienação social mas também da superação dessa alienação. É nessa tensão entre a alienação e a sua superação que a intervenção psicodramática propõe-se a buscar melhoria para a qualidade de resposta no trabalho, através da melhoria na qualidade de vida do trabalhador.

Teoria das mediações e estudos culturais: convergências e perspectivas

Este artigo procura resgatar, brevemente, o momento histórico em que a Teoria das Mediações e os Estudos Culturais desenvolveram-se e as categorias que construíram para compreender os processos de produção de sentido em um mundo no qual a comunicação mediada fez-se, cada vez, mais presente. Procura-se tratar, aqui, das convergências na orientação da pesquisa baseada nos trabalhos de Raymond Williams e as novas gerações dos Estudos Culturais (como Stuart Hall, Roger Silverstone, David Morley) com relação aos trabalhos de Jésus Martín-Barbero, Néstor Canclini e Guilhermo Orozco. Essas convergências e perspectivas precisam ser avaliadas, pois devem compor o referencial teórico de uma série de pesquisas com a produção de sentido em novos ambientes integrados às novas tecnologias. Tecnologias que possibilitam uma maior ou menor intervenção direta do usuário, cada vez mais, por meio de redes sem fio, e que podem tirar do espaço doméstico a primazia do contexto de fruição, usos e apropriações.

Neoconstitucionalismo e os novos desafios da teoria constitucional

O neoconstitucionalismo surge no horizonte da teoria constitucional trazendo novos elementos de debate para problemas antigos e novos. Os rumos que essa visão irá tomar ou que contribuições concretas poderá trazer na dinâmica social, ainda não sabemos, mas é quase certo que uma nova visão sobre a teoria constitucional parece estar em curso.

Histórias em quadrinhos no processo de aprendizado: da teoria à prática

Após décadas de rejeição por parte dos educadores, no final dos anos 1990 as histórias em quadrinhos começaram a conquistar seu espaço nas salas de aula brasileiras. No entanto, apesar dos avanços conseguidos, ainda é preciso adequar as aplicações possíveis deste produto cultural às necessidades do processo de aprendizado. Nesse sentido, neste artigo temos por objetivo fomentar e nortear o uso apropriado das narrativas sequenciais nas práticas educativas, discutindo os possíveis caminhos para sua implementação.

Transformações comunicacionais: a atuação no media training na perspectiva da teoria social cognitiva

Dissertação apresentada ao Programa de Pós-graduação em Comunicação da Universidade Municipal de São Caetano do Sul.

Estruturas de governança em redes de cooperativas de crédito sob a ótica da teoria dos custos de transação: um estudo comparativo entre cooperativas brasileiras e canadenses

Tese apresentada ao Programa de Pós-graduação em Administração da Universidade Municipal de São Caetano do Sul