Didàctiques llums i ombres platòniques en la poesia de Luis Cernuda

L'objectiu d'aquest article és revelar l'ús reiterat de les llums i les ombres en la poesia de Luis Cernuda, com a imatges que tenen com a referent concret -bé que no mencionat- la imatge platònica de la caverna. És justament gràcies a les imatges que el poeta ens mostra el seu univers ideal, en el qual la foscor simbolitza el món material condemnat a morir, mentre que la llum és el símbol del món bell, perfecte i etern en què Luis Cernuda necessita creure. Es tracta, un cop més, de la tensió entre realitat i desig que defineix l'essència de la seva poesia.

Consumption of macrophytes by invertebrates in Tancada lagoon (NE Spain)

Gammarus aequicauda and Sphaeroma hookeri are the most abundant macroinvertebrates on Ruppia cirrhosa (1275 and 1290 individuals.m-2) and Potamogeton pectinatus (140 and 680 individuals. m-2) in Tancada lagoon, a Mediterranean coastal lagoon in the Ebro Delta (NE Spain). Consumption and assimilation efficiencies were calculated from bell jar experiments. Gammarus grazing effects are higher than Sphaeroma on both Ruppia cirrhosa and Potamogeton pectinatus. Green Ruppia leaves lost 0.3 mg per mg Gammarus per day, while Potamogeton leaves lost 0.2 mg per mg Gammarus per day. Decomposing Ruppia leaves lost 0.35-0.54 mg per mg Gammarus per day. Losses of weight by both Ruppia and Potamogeton due to Sphaeroma feeding were less than half those by Gammarus. Assimilation efficiencies are higher for Gammarus (44-78% feeding on Ruppia 2% feeding on Potamogeton) than for Sphaeroma (26-48%) feeding on Ruppia). These assimilation efficiencies were higher than those reported by other authors working at higher latitudes perhaps because of the higher temperature under which the experiments were carried out.

Senex, el vell savi : Estudi del reconeixement del papa el 750

Breu assaig de caràcter hermenèutic on l'autor es proposa una lectura d'un esdeveniment històric particular. L'autor pren com a excusa per a la seva interpretació dels esdeveniments els fets que tingueren lloc el 750 al bell mig del regne franc quan els merovingis reconeixen explícitament la figura d'autoritat del papa en la comunitat cristiana occidental i com el papa l'assumeix pròpiament.

Maria-Mercè Marçal en el mirall : sobre l'imaginari femení i el llenguatge poètic

Per Maria-Mercè Marçal, la poeta no es pot trobar, no es pot veure, en el «mirall del bell», que sempre han fomentat els discursos dominants. El seu és una altra mena de mirall trencat que reflecteix un ésser complex, híbrid i contaminat que lluita «entre un jo que es vol fer i els múltiples personatges que, des del mirall, li retornen una imatge múltiple». En aquest article, per explorar el tema de l’imaginari femení i el llenguatge poètic, hem escollit dialogar amb Maria- Mercè Marçal i examinar tres dels múltiples bocins que conformen la seva imatge en el mirall. Conversem amb dues mares i un pare simbòlics de l’altre cantó del seu espill, tots tres proveïdors de material ideològic i eixos vertebradors dels assaigs marçalians. Es tracta d’intel·lectuals ben diversos: l’escriptora anglesa Virginia Woolf, el filòsof francès Jacques Derrida i la poeta catalana Maria-Antònia Salvà. En definitiva, dividim la investigació en tres apartats, que volen coincidir amb el diàleg que Marçal suposem que hi mantingué. De primer, amb Virginia Woolf, explorem la necessitat de la poeta de descobrir el sentiment de «fúria» que porta a dins per tal d’assumir la irracionalitat del seu llenguatge. Després, ens endinsem en les teories derridianes sobre la dona i l’escriptura, en un intent de demostrar que ambdues són espècies híbrides que viuen en el llindar, en un espai d’entremig. A l’últim, amb Maria-Antònia Salvà, revisem la imatge de la dona-monstre amb la certesa que «el salvatge» i «l’incert » són el motor del llenguatge poètic femení.

Anàlisi experimental de la capacitat d'emmagatzematge d'energia tèrmica de dos tancs connectats en cascada amb diferent pcm

En aquest treball es pretén estudiar el potencial d'emmagatzematge d'energia tèrmica, per aplicacions de refrigeració solar d'un sistema format per dos tancs intercanviadors acumuladors connectats en cascada. Cada tanc conté un PCM diferent amb diferent temperatura de canvi de fase. Concretament es tracta d'hidroquinona i d-mannitol. Els quals posseixen temperatures de canvi de fase entre 140 i 200 Cº requerides per aplicacions de fred solar. També es pretén comparar el sistema en cascada amb el mateix sistema connectat en paral·lel.

Apego adulto en mujeres adoptadas: un estudio de caso sobre su relación con la construcción de la identidad

En este estudio partimos de un posicionamiento constructivista relacional (Botella, Herrero, Pacheco y Corbella, 2004) y de la Teoría del Apego (Bowlby, 1969) para el análisis del apego adulto y de su relación con la construcción de la identidad de una mujer de treinta y cinco años (Sara), adoptada a los tres. Es una investigación metodológicamente plural, puesto que incluye tanto metodologías cuantitativas como cualitativas. Analizamos una narrativa de identidad de Sara, mediante el método cualitativo de Grounded Theory (Glaser y Strauss, 1967). Administramos también el cuestionario ECR-S (Alonso-Arbiol, Balluerka y Shaver, 2007) para evaluar el apego adulto y la Rejilla de Constructos Personales (Kelly, 1955/1991) referida a la construcción del sí mismo (Butt, Burr y Bell, 1997) analizada mediante el programa RECORD (Feixas y Cornejo, 1996). Los resultados confirman la literatura previa (por ejemplo, Grosso y Nagliero, 2004; Negre, Forns y Freixa, 2007) y muestran una reconstrucción positiva en el modelo de funcionamiento interno de Sara, a partir de la resolución de dudas sobre su origen biológico. Los resultados del análisis de la Rejilla confirman que las características del patrón de apego con la madre y con el padre no tienen por qué ser similares y que una mujer puede construir su posicionamiento como madre a partir de la relación con su padre. También indican la presencia de conflictos cognitivos en la construcción de la identidad. Los resultados se discuten a la luz de investigaciones previas.

Consumption of macrophytes by invertebrates in Tancada lagoon (NE Spain)

Gammarus aequicauda and Sphaeroma hookeri are the most abundant macroinvertebrates on Ruppia cirrhosa (1275 and 1290 individuals.m-2) and Potamogeton pectinatus (140 and 680 individuals. m-2) in Tancada lagoon, a Mediterranean coastal lagoon in the Ebro Delta (NE Spain). Consumption and assimilation efficiencies were calculated from bell jar experiments. Gammarus grazing effects are higher than Sphaeroma on both Ruppia cirrhosa and Potamogeton pectinatus. Green Ruppia leaves lost 0.3 mg per mg Gammarus per day, while Potamogeton leaves lost 0.2 mg per mg Gammarus per day. Decomposing Ruppia leaves lost 0.35-0.54 mg per mg Gammarus per day. Losses of weight by both Ruppia and Potamogeton due to Sphaeroma feeding were less than half those by Gammarus. Assimilation efficiencies are higher for Gammarus (44-78% feeding on Ruppia 2% feeding on Potamogeton) than for Sphaeroma (26-48%) feeding on Ruppia). These assimilation efficiencies were higher than those reported by other authors working at higher latitudes perhaps because of the higher temperature under which the experiments were carried out.

Heat shock response in yeast involves changes in both transcription rates and mRNA stabilities

We have analyzed the heat stress response in the yeast Saccharomyces cerevisiae by determining mRNA levels and transcription rates for the whole transcriptome after a shift from 25uC to 37uC. Using an established mathematical algorithm, theoretical mRNA decay rates have also been calculated from the experimental data. We have verified the mathematical predictions for selected genes by determining their mRNA decay rates at different times during heat stress response using the regulatable tetO promoter. This study indicates that the yeast response to heat shock is not only due to changes in transcription rates, but also to changes in the mRNA stabilities. mRNA stability is affected in 62% of the yeast genes and it is particularly important in shaping the mRNA profile of the genes belonging to the environmental stress response. In most cases, changes in transcription rates and mRNA stabilities are homodirectional for both parameters, although some interesting cases of antagonist behavior are found. The statistical analysis of gene targets and sequence motifs within the clusters of genes with similar behaviors shows that both transcriptional and post-transcriptional regulons apparently contribute to the general heat stress response by means of transcriptional factors and RNA binding proteins.

Grx5 is a mitochondrial glutaredoxin required for the activity of iron/sulfur enzymes

Yeast cells contain a family of three monothiol glutaredoxins: Grx3, 4, and 5. Absence of Grx5 leads to constitutive oxidative damage, exacerbating that caused by external oxidants. Phenotypic defects associated with the absence of Grx5 are suppressed by overexpression ofSSQ1 and ISA2, two genes involved in the synthesis and assembly of iron/sulfur clusters into proteins. Grx5 localizes at the mitochondrial matrix, like other proteins involved in the synthesis of these clusters, and the mature form lacks the first 29 amino acids of the translation product. Absence of Grx5 causes: 1) iron accumulation in the cell, which in turn could promote oxidative damage, and 2) inactivation of enzymes requiring iron/sulfur clusters for their activity. Reduction of iron levels in grx5 null mutants does not restore the activity of iron/sulfur enzymes, and cell growth defects are not suppressed in anaerobiosis or in the presence of disulfide reductants. Hence, Grx5 forms part of the mitochondrial machinery involved in the synthesis and assembly of iron/sulfur centers.

An activator/repressor dual system allows tight tetracycline-regulated gene expression in budding yeast

We have developed an activator/repressor expression system for budding yeast in which tetracyclines control in opposite ways the ability of tetR-based activator and repressor molecules to bind tetO promoters. This combination allows tight expression of tetO-driven genes, both in a direct (tetracycline-repressible) and reverse (tetracycline-inducible) dual system. Ssn6 and Tup1, that are components of a general repressor complex in yeast, have been tested for their repressing properties in the dual system, using lacZ and CLN2 as reporter genes. Ssn6 gives better results and allows complete switching-off of the regulated genes, although increasing the levels of the Tup1-based repressor by expressing it from a stronger promoter improves repressing efficiency of the latter. Effector-mediated shifts between expression and non-expression conditions are rapid. The dual system here described may be useful for the functional analysis of essential genes whose conditional expression can be tightly controlled by tetracyclines.

Evolution and cellular function of monothiol glutaredoxins: involvement in iron-sulphur cluster assembly

A number of bacterial species, mostly proteobacteria, possess monothiol glutaredoxins homologous to the Saccharomyces cerevisiae mitochondrial protein Grx5, which is involved in iron–sulphur cluster synthesis. Phylogenetic profiling is used to predict that bacterial monothiol glutaredoxins also participate in the iron–sulphur cluster (ISC) assembly machinery, because their phylogenetic profiles are similar to the profiles of the bacterial homologues of yeast ISC proteins. High evolutionary cooccurrence is observed between the Grx5 homologues and the homologues of the Yah1 ferredoxin, the scaffold proteins Isa1 and Isa2, the frataxin protein Yfh1 and the Nfu1 protein. This suggests that a specific functional interaction exists between these ISC machinery proteins. Physical interaction analyses using low-definition protein docking predict the formation of strong and specific complexes between Grx5 and several components of the yeast ISC machinery. Two-hybrid analysis has confirmed the in vivo interaction between Grx5 and Isa1. Sequence comparison techniques and cladistics indicate that the other two monothiol glutaredoxins of S. cerevisiae, Grx3 and Grx4, have evolved from the fusion of a thioredoxin gene with a monothiol glutaredoxin gene early in the eukaryotic lineage, leading to differential functional specialization. While bacteria do not contain these chimaeric glutaredoxins, in many eukaryotic species Grx5 and Grx3/4-type monothiol glutaredoxins coexist in the cell.

Glutaredoxins Grx3 and Grx4 regulate nuclear localisation of Aft1 and the oxidative stress response in Saccharomyces cerevisiae

Grx3 and Grx4, two monothiol glutaredoxins of Saccharomyces cerevisiae, regulate Aft1 nuclear localisation. We provide evidence of a negative regulation of Aft1 activity by Grx3 and Grx4. The Grx domain of both proteins played an important role in Aft1 translocation to the cytoplasm. This function was not, however, dependent on the availability of iron. Here we demonstrate that Grx3, Grx4 and Aft1 interact each other both in vivo and in vitro, which suggests the existence of a functional protein complex. Interestingly, each interaction occurred independently on the third member of the complex. The absence of both Grx3 and Grx4 induced a clear enrichment of G1 cells in asynchronous cultures, a slow growth phenotype, the accumulation of intracellular iron and a constitutive activation of the genes regulated by Aft1. The grx3grx4 double mutant was highly sensitive to the oxidising agents hydrogen peroxide and t-butylhydroperoxide but not to diamide. The phenotypes of the double mutant grx3grx4 characterised in this study were mainly mediated by the Aft1 function, suggesting that grx3grx4 could be a suitable cellular model for studying endogenous oxidative stress induced by deregulation of the iron homeostasis. However, our results also suggest that Grx3 and Grx4 might play additional roles in the oxidative stress response through proteins other than Aft1.

Lyotard y La condició postmoderna, Vint-i-cinc anys després

L"any 1979 Jean-François Lyotard (1924-1998) publicava a París La condition postmoderne. Rapport sur le savoir, editat per Les Éditions de Minuit, obra en què es retratava l"home postmodern i que amb el pas dels anys s"ha convertit en una mena de clàssic del pensament contemporani. La tesi de fons del llibre -una obra encarregada per les autoritats del Quebec- és ben coneguda: el saber canvia d"estatut al mateix temps que les societats entren en l"era anomenada postindustrial, segons havien anunciat Daniel Bell i Alain Touraine. Per tant, la qüestió del saber en aquesta època postindustrial -que a grans trets coincideix amb un esperit d"època (Zeitgeist) que es pot identifi car amb la postmodernitat- cal situar-la en la perspectiva de les societats industrials avançades.

Neuronal activity controls the antagonistic between PGC-1α and SMRT in regulating antioxidant defences

Transcriptional coactivators and corepressors often have multiple targets and can have opposing actions on transcription and downstream physiological events. The coactivator peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α is under-expressed in Huntington's disease and is a regulator of antioxidant defenses and mitochondrial biogenesis. We show that in primary cortical neurons, expression of PGC-1α strongly promotes resistance to excitotoxic and oxidative stress in a cell autonomous manner, whereas knockdown increases sensitivity. In contrast, the transcriptional corepressor silencing mediator of retinoic acid and thyroid hormone receptors (SMRT) specifically antagonizes PGC-1α-mediated antioxidant effects. The antagonistic balance between PGC-1α and SMRT is upset in favor of PGC-1α by synaptic activity. Synaptic activity triggers nuclear export of SMRT reliant on multiple regions of the protein. Concommitantly, synaptic activity post-translationally enhances the transactivating potential of PGC-1α in a p38-dependent manner, as well as upregulating cyclic-AMP response element binding protein-dependent PGC-1α transcription. Activity-dependent targeting of PGC-1α results in enhanced gene expression mediated by the thyroid hormone receptor, a prototypical transcription factor coactivated by PGC-1α and repressed by SMRT. As a consequence of these events, SMRT is unable to antagonize PGC-1α-mediated resistance to oxidative stress in synaptically active neurons. Thus, PGC-1α and SMRT are antagonistic regulators of neuronal vulnerability to oxidative stress. Further, this coactivatorcorepressor antagonism is regulated by the activity status of the cell, with implications for neuronal viability.

Managing innovations in biotechnology

Estudi de la situació, estratègies i tendències de la gestió de les innovacions en biotecnologia. El projecte es desenvolupa amb participants de Polònia, França, Holanda i Espanya. Per tant, l'anàlisi té una perspectiva internacional, principalment centrada en els països esmentats. L'expliació teòrica contrasta amb un projecte de gestió real en una empresa de biotecnologia, amb les dades i la informació obtinguda en una visitat a una empresa de biotecnologia a Polònia