1,831 research outputs found

    ¿Se pueden alcanzar los objetivos de la escuela de Frankfurt mediante la teoría del reconocimiento? Reflexiones a propósito de la controversia en el campo de la filosofía política de Nancy Fraser y Axel Honneth

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    De los estudios en ciencias sociales de mayor impacto se deduce que la política de mercantilización y desestructuración de las instituciones del Estado social practicada en los últimos treinta años, pri mero en Gran Bretaña, los Estados Unidos y Nueva Zelanda y después en el continente europeo, generará formas de empleo que, cada vez más, serían experimentadas por las personas como pro blemáticas o amenazantes (cf ., p. ej ., Bourdieu et al., 1997, Castel, 2000 y 2005, así como Sennet 1998 y 2005). Parecen responsables de este hecho, ante todo, las exigencias de movilidad que aumentan con la flexibilización de las estructuras de empleo, así como también un fuerte incremento de las ocupaciones inestables y mal pagadas (como, por ejemplo, los trabajos tempora les o a tiempo parcial). Según la apreciación de destacados sociólogos, aquellas estructuras de ocupación resultan problemáticas para muchas personas no únicamente en sentido material, sino también en sentido normativo: no sólo acarrean una situación de conflict o en el mantenimiento de la propia vida, sino que también dificultan la formación del autoaprecio y de la autoestima de una parte de la ciudadanía. A la vista de esta circunstancias , no resulta sorprendente que las cuesti ones del mundo del trabajo hayan sido discutidas ampliamente por personas que se dedican tanto a las ciencias sociales y a la ética de la economía, como también a la filosofía política o social. Para la Teoría Crítica en la tradición de la Escuela de Frankfurt , la discusión sobre los modernos mundos del trabajo resulta tradicionalmente un tema central. La peculiaridad de su planteamiento (interdis ciplinar) consiste , según la convicción de dos de sus más prominentes representantes, en : fusionar aquellos planos que provienen de la filosofía moral, de la teoría de la sociedad y del análisis político, en una teoría crítica del capitalismo (Fraser & Honnet h, 2003: 10). Lo que se plantea en esta perspectiva es un análisis y una crítica

    Towards a structure-based exciton Hamiltonian for the CP29 antenna of photosystem II

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    The exciton Hamiltonian pertaining to the first excited states of chlorophyll (Chl) a and b pigments in the minor light-harvesting complex CP29 of plant photosystem II is determined based on the recent crystal structure at 2.8 Å resolution applying a combined quantum chemical/electrostatic approach as used earlier for the major light-harvesting complex LHCII. Two electrostatic methods for the calculation of the local transition energies (site energies), referred to as the Poisson–Boltzmann/quantum chemical (PBQC) and charge density coupling (CDC) method, which differ in the way the polarizable environment of the pigments is described, are compared and found to yield comparable results, when tested against fits of measured optical spectra (linear absorption, linear dichroism, circular dichroism, and fluorescence). The crystal structure shows a Chl a/b ratio of 2.25, whereas a ratio between 2.25 and 3.0 can be estimated from the simulation of experimental spectra. Thus, it is possible that up to one Chl b is lost in CP29 samples. The lowest site energy is found to be located at Chl a604 close to neoxanthin. This assignment is confirmed by the simulation of wild-type-minus-mutant difference spectra of reconstituted CP29, where a tyrosine residue next to Chl a604 is modified in the mutant. Nonetheless, the terminal emitter domain (TED), i.e. the pigments contributing mostly to the lowest exciton state, is found at the Chl a611–a612–a615 trimer due to strong excitonic coupling between these pigments, with the largest contributions from Chls a611 and a612. A major difference between CP29 and LHCII is that Chl a610 is not the energy sink in CP29, which is presumably to a large extent due to the replacement of a lysine residue with alanine close to the TED

    Recognition and property in Hegel and the early Marx

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    The article attempts to show, first, that for Hegel the role of property is to enable persons both to objectify their freedom and to properly express their recognition of each other as free, and second, that the Marx of 1844 uses fundamentally similar ideas in his exposition of communist society. For him the role of ‘true property’ is to enable individuals both to objectify their essential human powers and their individuality, and to express their recognition of each other as fellow human beings with needs, or their ‘human recognition’. Marx further uses these ideas to condemn the society of private property and market exchange as characterised by ‘estranged’ forms of property and recognition. He therefore uses a structure of ideas which Hegel had used to justify the institutions of private property and market exchange in order to condemn those same institutions. It is concluded that Marx’s adoption from Hegel of the idea that property as the means of self-objectification and of expressed recognition, leaves his vision of communism open to the charge that in it, just as in market society, the relations between human beings are mediated by things

    Associations between reliable changes in depression and changes in BMI, total body fatness and visceral adiposity during a 12-month weight loss trial.

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    We investigated associations between changes in depression and body composition over a 12-month weight loss trial. Of the 298 adults (BMI > 27 m/kg2), 219 with complete depression and body composition data were included. A 10-item Center for Epidemiologic Studies Depression Scale measured depression; dual-energy X-ray absorptiometry measured body composition. Multinomial logistic regression predicted reliable changes in depression by BMI, body fat (BF) and visceral adiposity (VAT). Multiplicative interaction terms tested modification by sex and ethnicity. Participants with increases in body composition were less likely to experience improvements in depression (BMI: RRR = 0.79 (0.68-0.91), p < 0.01; BF: RRR = 0.97 (0.94 - 0.99), p = 0.01; VAT: RRR = 0.99 (0.98-1.00), p = 0.02), but not worsening of depression (BMI: RRR = 1.29 (0.96-1.73), p = 0.10; BF: RRR = 1.04 (0.99-1.09), p = 0.15; VAT: RRR = 1.01 (1.00-1.03), p = 0.18). Sex and ethnicity interaction terms were not significant. However, the relationship was only significant among females, among non-Latinos for BMI and BF, and among Latinos for VAT. Our study supports the association between depression and obesity and highlights the need for longitudinal studies investigating VAT and depression in diverse ethnic groups

    Vortex deformation and breaking in superconductors: A microscopic description

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    Vortex breaking has been traditionally studied for nonuniform critical current densities, although it may also appear due to nonuniform pinning force distributions. In this article we study the case of a high-pinning/low-pinning/high-pinning layered structure. We have developed an elastic model for describing the deformation of a vortex in these systems in the presence of a uniform transport current density JJ for any arbitrary orientation of the transport current and the magnetic field. If JJ is above a certain critical value, JcJ_c, the vortex breaks and a finite effective resistance appears. Our model can be applied to some experimental configurations where vortex breaking naturally exists. This is the case for YBa2_2Cu3_3O7x_{7-x} (YBCO) low angle grain boundaries and films on vicinal substrates, where the breaking is experienced by Abrikosov-Josephson vortices (AJV) and Josephson string vortices (SV), respectively. With our model, we have experimentally extracted some intrinsic parameters of the AJV and SV, such as the line tension ϵl\epsilon_l and compared it to existing predictions based on the vortex structure.Comment: 11 figures in 13 files; minor changes after printing proof

    Spatial heterogeneity and peptide availability determine CTL killing efficiency in vivo

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    The rate at which a cytotoxic T lymphocyte (CTL) can survey for infected cells is a key ingredient of models of vertebrate immune responses to intracellular pathogens. Estimates have been obtained using in vivo cytotoxicity assays in which peptide-pulsed splenocytes are killed by CTL in the spleens of immunised mice. However the spleen is a heterogeneous environment and splenocytes comprise multiple cell types. Are some cell types intrinsically more susceptible to lysis than others? Quantitatively, what impacts are made by the spatial distribution of targets and effectors, and the level of peptide-MHC on the target cell surface? To address these questions we revisited the splenocyte killing assay, using CTL specific for an epitope of influenza virus. We found that at the cell population level T cell targets were killed more rapidly than B cells. Using modeling, quantitative imaging and in vitro killing assays we conclude that this difference in vivo likely reflects different migratory patterns of targets within the spleen and a heterogeneous distribution of CTL, with no detectable difference in the intrinsic susceptibilities of the two populations to lysis. Modeling of the stages involved in the detection and killing of peptide-pulsed targets in vitro revealed that peptide dose influenced the ability of CTL to form conjugates with targets but had no detectable effect on the probability that conjugation resulted in lysis, and that T cell targets took longer to lyse than B cells. We also infer that incomplete killing in vivo of cells pulsed with low doses of peptide may be due to a combination of heterogeneity in peptide uptake and the dissociation, but not internalisation, of peptide-MHC complexes. Our analyses demonstrate how population-averaged parameters in models of immune responses can be dissected to account for both spatial and cellular heterogeneity

    Computational Methodologies and Physical Insights into Electronic Energy Transfer in Photosynthetic Light-Harvesting Complexes

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    We examine computational techniques and methodologies currently in use to explore electronic excitation energy transfer in the context of light-harvesting complexes in photosynthetic antenna systems, and comment on some new insights into the underlying physics. Advantages and pitfalls of these methodologies are discussed, as are some physical insights into the photosynthetic dynamics. By combining results from molecular modelling of the complexes (structural description) with an effective non-equilibrium statistical description (time evolution), we identify some general features, regardless of the particular distribution in the protein scaffold, that are central to light-harvesting dynamics and, that could ultimately be related to the high efficiency of the overall process. Based on these general common features, some possible new directions in the field are discussed.Comment: Invited Perspective Article for Phys. Chem. Chem. Phy
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