Entre experiencia y estructura : sufrimiento social, identidades colectivas y justicia en Iris Marion Young

This paper analyzes the role of phenomenology in Iris Marion Young's model of critical theory through a discussion of the different strategies she mobilizes in articulating the notions of identity and social collectivities in Justice and the Politics of Difference (1990) and Inclusion and Democracy (2000). By reconstructing the debate Young had with Nancy Fraser during the 1990s, we seek to demonstrate that, although Fraser mischaracterizes Justice and Politics of Difference as representative of the “cultural turn” in social theory, her criticisms can illuminate some of the tensions and shortcomings of the text. Moreover, we argue that the emphasis in a structural-analytical strategy of argumentation, characteristic of Young's later work, can be traced back to the contentions formulated by Fraser. Nonetheless, it is sustained in a final step that Young never completely abdicated the phenomenological approach as a tool for social criticism. Although the argument of Inclusion and Democracy is developed primarily in a structural way, Young repeatedly mobilizes the experiences of social suffering and the demands for justice voiced by social movements as the basis of her large scale democratic proposals.Este artículo analiza el papel de la fenomenología en el modelo de la teoría crítica de Iris Marion Young a través de una discusión de las diferentes estrategias que utiliza para articular las nociones de identidad y colectividades sociales en La justicia y la política de la diferencia (1990) y en Inclusion and Democracy (2000). Al reconstruir el debate que Young tuvo con Nancy Fraser durante la década de los 90, buscamos demostrar que, aunque Fraser malinterpreta La justicia y la política de la diferencia como representante del “giro cultural” en la teoría social, sus críticas pueden iluminar algunas de las tensiones y defectos del texto. Además, sostenemos que el énfasis en una estrategia estructural-analítica de la argumentación, característica del trabajo posterior de Young, puede rastrearse hasta los argumentos formulados por Fraser. Sin embargo, se sostiene en un paso final que Young nunca abdicó completamente del enfoque fenomenológico como herramienta para la crítica social. Aunque el argumento de Inclusion and Democracy es desarrollado principalmente de manera estructural, Young utiliza repetidamente las experiencias de sufrimiento social y las demandas de justicia expresadas por movimientos sociales como base de sus propuestas democráticas a gran escala

On Useful Conformal Tranformations In General Relativity

Local conformal transformations are known as a useful tool in various applications of the gravitational theory, especially in cosmology. We describe some new aspects of these transformations, in particular using them for derivation of Einstein equations for the cosmological and Schwarzschild metrics. Furthermore, the conformal transformation is applied for the dimensional reduction of the Gauss-Bonnet topological invariant in $d=4$ to the spaces of lower dimensions.Comment: 17 pages, LaTeX. The paper is intended mainly for pedagogical purposes and represents a collection of exercises concerning local conformal transformations and dimensional reduction. To be published in "Gravitation and Cosmology

Dynamo in the Intra-Cluster Medium: Simulation of CGL-MHD Turbulent Dynamo

The standard magnetohydrodynamic (MHD) description of the plasma in the hot, magnetized gas of the intra-cluster (ICM) medium is not adequate because it is weakly collisional. In such collisionless magnetized gas, the microscopic velocity distribution of the particles is not isotropic, giving rise to kinetic effects on the dynamical scales. These kinetic effects could be important in understanding the turbulence, as so as the amplification and maintenance of the magnetic fields in the ICM. It is possible to formulate fluid models for collisonless or weakly collisional gas by introducing modifications in the MHD equations. These models are often referred as kinetic MHD (KMHD). Using a KMHD model based on the CGL-closure, which allows the adiabatic evolution of the two components of the pressure tensor (the parallel and perpendicular components with respect to the local magnetic field), we performed 3D numerical simulations of forced turbulence in order to study the amplification of an initially weak seed magnetic field. We found that the growth rate of the magnetic energy is comparable to that of the ordinary MHD turbulent dynamo, but the magnetic energy saturates in a level smaller than of the MHD case. We also found that a necessary condition for the dynamo works is to impose limits to the anisotropy of the pressure.Comment: 3 pages, 1 figure, 274 IAU Symposium: Advances in Plasma Astrophysic

Features of collisionless turbulence in the intracluster medium from simulated Faraday Rotation maps

Observations of the intracluster medium (ICM) in galaxy clusters suggest for the presence of turbulence and the magnetic fields existence has been proved through observations of Faraday Rotation and synchrotron emission. The ICM is also known to be filled by a rarefied weakly collisional plasma. In this work we study the possible signatures left on Faraday Rotation maps by collisionless instabilities. For this purpose we use a numerical approach to investigate the dynamics of the turbulence in collisionless plasmas based on an magnetohydrodynamical (MHD) formalism taking into account different levels of pressure anisotropy. We consider models covering the sub/super-Alfv\'enic and trans/supersonic regimes, one of them representing the fiducial conditions corresponding to the ICM. From the simulated models we compute Faraday Rotation maps and analyze several statistical indicators in order to characterize the magnetic field structure and compare the results obtained with the collisionless model to those obtained using standard collisional MHD framework. We find that important imprints of the pressure anisotropy prevails in the magnetic field and also manifest in the associated Faraday Rotation maps which evidence smaller correlation lengths in the collisionless MHD case. These points are remarkably noticeable for the case mimicking the conditions prevailing in ICM. Nevertheless, in this study we have neglected the decrease of pressure anisotropy due to the feedback of the instabilities that naturally arise in collisionless plasmas at small scales. This decrease may not affect the statistical imprint differences described above, but should be examined elsewhere.Comment: 24 pages, 15 figures, MNRAS accepte

Crystallographic groups and flat manifolds from surface braid groups

Let $M$ be a compact surface without boundary, and $n\geq 2$. We analyse the quotient group $B_n(M)/\Gamma_2(P_n(M))$ of the surface braid group $B_{n}(M)$ by the commutator subgroup $\Gamma_2(P_n(M))$ of the pure braid group $P_{n}(M)$. If $M$ is different from the $2$-sphere $\mathbb{S}^2$, we prove that $B_n(M)/\Gamma_2(P_n(M))$ is isomorphic rho $P_n(M)/\Gamma_2(P_n(M)) \rtimes_{\varphi} S_n$, and that $B_n(M)/\Gamma_2(P_n(M))$ is a crystallographic group if and only if $M$ is orientable. If $M$ is orientable, we prove a number of results regarding the structure of $B_n(M)/\Gamma_2(P_n(M))$. We characterise the finite-order elements of this group, and we determine the conjugacy classes of these elements. We also show that there is a single conjugacy class of finite subgroups of $B_n(M)/\Gamma_2(P_n(M))$ isomorphic either to $S_n$ or to certain Frobenius groups. We prove that crystallographic groups whose image by the projection $B_n(M)/\Gamma_2(P_n(M))\to S_n$ is a Frobenius group are not Bieberbach groups. Finally, we construct a family of Bieberbach subgroups $\tilde{G}_{n,g}$ of $B_n(M)/\Gamma_2(P_n(M))$ of dimension $2ng$ and whose holonomy group is the finite cyclic group of order $n$, and if $\mathcal{X}_{n,g}$ is a flat manifold whose fundamental group is $\tilde{G}_{n,g}$, we prove that it is an orientable K\"ahler manifold that admits Anosov diffeomorphisms

MHD turbulence-Star Formation Connection: from pc to kpc scales

The transport of magnetic flux to outside of collapsing molecular clouds is a required step to allow the formation of stars. Although ambipolar diffusion is often regarded as a key mechanism for that, it has been recently argued that it may not be efficient enough. In this review, we discuss the role that MHD turbulence plays in the transport of magnetic flux in star forming flows. In particular, based on recent advances in the theory of fast magnetic reconnection in turbulent flows, we will show results of three-dimensional numerical simulations that indicate that the diffusion of magnetic field induced by turbulent reconnection can be a very efficient mechanism, especially in the early stages of cloud collapse and star formation. To conclude, we will also briefly discuss the turbulence-star formation connection and feedback in different astrophysical environments: from galactic to cluster of galaxy scales.Comment: 6 pages, 5 figures, 274 IAU Symposium: Advances in Plasma Astrophysic

Contributos para uma observação efectiva do design em Portugal

Mestrado em Design, Materiais e Gestão do ProdutoEsta dissertação pretende dar relevo . problemática da observação do Design em Portugal, através duma reflexão que estabeleça as bases para a construção de um Observatório Português do Design. A necessidade da aquisição de conhecimentos rigorosos e fiáveis sobre o Design que se pratica em Portugal e as actividades com ele relacionadas, bem como a sua posterior divulgação, são os factores que estiveram na origem desta investigação. A noção de que o Design é hoje encarado como um factor fundamental nos processos de crescimento económico, tanto nas empresas como nos países, tem cada vez mais defensores. A sua crescente import.ncia enquanto ferramenta estratégica, foi demonstrada pelo recente interesse que o Design despoletou na conferência da "World Economic Forum" realizada em Davos (Suiça, 2006), onde se reuniram os países mais desenvolvidos do mundo para discutirem o futuro económico e social do planeta. Foram realizados cerca de 22 eventos relacionados com o Design, o que é um sintoma de que os decisores políticos e económicos começam a dar uma grande relevência a esta disciplina. Partindo da ideia da constituição de um observatório do Design em Portugal, esta dissertação aborda o estudo e observação do Design, bem como as políticas para a sua promoção, implantação e desenvolvimento nas economias. Esta investigação centra-se no estudo de vários observatórios, na análise às diferentes políticas (regionais, nacionais, e internacionais) adoptadas por diversos países, e aborda casos de estudo sobre a observação do Design em países líderes na sua utilização. Deste modo, verifica modelos e metodologias de observação e estabelece, a partir deles, possiveis sistemas, campos e áreas de anílise que ficam como ponto de partida para a discussão do estudo do Design em Portugal. A reflexão teórica sobre esta temática, serà desenvovida tendo em conta os seguintes vectores: - Análise a vários observatórios, com o objectivo de identificar: estruturas de organização, tipo de parcerias envovidas e modelos adaptados; objectivos, funções e métodos de comunicação; sistemas e metodologias de observação. - Enquadramento do conceito "Design", enquanto disciplina estratégica para a economia e sua ligação a factores como a inovação e a competitividade - Análise a vários tipos de políticas de promoção e implementação do Design em diversos países, a experiências feitas nesta área pela Irlanda e pelo Chile, e à situação portuguesa nesta matéria. - Estudo de metodologias na observação do Design, através de casos patrocinados por países europeus, líderes na sua utlização: Finlândia, França e Reino Unido. - Análise de alguns estudos e suas metodologias de observação, realizados em Portugal. Verificação, por comparação com os estudos europeus, do grau de eficácia da informação obtida nesses estudos. - Análise ao papel do Centro Português de Design no estudo, observação, promoção e desenvolvimento do Design em Portugal, com relevância para o lançamento do Observatório do Design em 2000. Reflexões sobre o que poderá ser o sistema do Design em Portugal, seus campos de observação e de análise, visão, missão e objectivos de um futuro observatório português do Design, sua constituição, parcerias envolvidas e métodos de comunicação. O presente trabalho, deixa assim, pistas e sugestões para a caracterização do Design enquanto factor estratégico, a adopção de políticas para a sua implantação nos vários sectores da sociedade e, sobretudo, para a edificação de uma estrutura que aglutine o estudo, pesquisa e investigação da sua influência na economia, no ensino e na vida dos portugueses. ABSTRACT: This dissertation aims at underlining the issue of Design observation in Portugal through careful consideration, establishing the basis for the creation of a Portuguese Design Observatory. The need to acquire a rigorous and reliable knowledge on current design practice in Portugal and related activities, as well as their subsequent dissemination, was in the basis of this investigation. The concept that today Design is a fundamental issue in the economical growth process, both for companies and for countries, is gaining increasing support. Its growing importance as a strategic tool was shown by the recent interest that Design triggered in the World Economic Forum in Davos (Switzerland, 2006), where the world’s most developed countries gathered to discuss the economic and social future of the planet. Approximately 22 events related to Design were conducted, showing that policy-makers and economic leaders are beginning to give considerable relevance to this discipline. This work arises from the idea of creating a Design Observatory in Portugal and deals with Design study and observation, as well as with its promotion, implementation, and development policies in economies. This research is focused on the study of several observatories and on the analysis of regional, national and international policies adopted in several countries. It considers case studies on Design observation in leading countries in this area, thus assessing observation models and methodologies and establishing from them possible analysis systems, fields and areas which serve as a starting point for discussing Design in Portugal. Theoretical considerations on this theme will be developed, bearing in mind the following aspects: - Analysis of various observatories to identify: organization structures, type of involved partnerships and adapted models; communication objectives, functions and methods; observation systems and methodologies. - Framework of the "Design" concept as a strategic discipline for economy, and its connection to issues such as innovation and competitiveness. - Analysis of several types of Design promotion and implementation policies in various countries, of the Irish and Chilean experiences and assessment of the Portuguese situation in this matter. - Study of three methodological types of Design observation by assessing european cases sponsored by leading countries in its use: Finland, France, and the United Kingdom. - Analysis of some studies and its comment methodologies, carried through in Portugal. Verification, for comparison with the european studies, of the degree of effectiveness of the information gotten in these studies. - Assessment of the adaptability degree of the models which were implemented in Portugal by comparison with a Finnish study. - Analysis of the role of the Centro Português de Design (Portuguese Design Centre) in the study, observation, promotion, and development of Design in Portugal. The launch of the Design observatory in 2000 deservs special consideration. Considerations on the potential future of the Design system in Portugal, its observation and analysis fields; perspectives, mission and objectives of a future Portuguese Design observatory, as well as its foundation, partnerships involved and communication methods. The present work offers clues and suggestions for characterizing Design as a strategic factor, adopting policies for its implementation in the various society sectors and, above all, for creating a structure which gathers studies, search and research of its influence in Portuguese economy, teaching and life