Comment on "Direct evidence for hidden one-dimensional Fermi surface of hexagonal K0.25WO3"

We comment a recent work titled "Direct evidence for hidden one-dimensional Fermi surface of hexagonal K0.25WO3". In this paper the authors report photoemission and theoretical results on the K0.25WO3 system which led them to propose that a Charge Density Wave (CDW), associated with hidden one-dimensional bands, was responsible for the well known resistivity anomaly in such system. In the present comment we report the results of a first principles density functional theory (DFT) study showing that there are no one-dimensional bands as suggested by these authors

Sovereignti-e-s

Quan el sistema econòmic i polític col·lapsa i la matriu cultural deixa de ser un referent de significat, és un bon moment per recordar algunes màximes dels antics grecs. Pensaments i intuïcions que responien a qüestions ètiques en un context de corrupció, on la paraula no tenia més valor que el de convèncer, on la veritat es confonia amb la raó i on les lleis humanes començaven a definir-se en contraposició a la naturalesa. Sentències com “ocupa’t del tot “o “la mesura és el millor” ens resulten familiars en un moment en què hem d’aprendre novament què és l’essencial i quant és suficient.Cuando el sistema económico y político colapsa y la matriz cultural deja de ser un referente de significado, es un buen momento para recordar algunas máximas de los antiguos griegos. Pensamientos e intuiciones que respondían a cuestiones éticas en un contexto de corrupción, donde la palabra no tenía más valor que el de convencer, donde la verdad se confundía con la razón y donde las leyes humanas empezaban a definirse en contra posición a la naturaleza. Sentencias como “ocúpate del todo” o “la mesura es lo mejor” nos resultan familiares en un momento en que tenemos que aprender nuevamente qué es esencial y cuánto es suficiente.When the political and economic system collapses and the cultural matrix stops being a referent for meaning, it is a good time to remember some maxims of the ancient Greeks. Thoughts and insights that respond to ethical issues in a context of corruption, where words had no more value than the one of convincing, where truth is confused with reason and where human laws began to define their position against nature. Judgments like "take care of the whole" or "moderation is best" are familiar to us in a time when we have to learn again what is essential and how much is enoughPeer Reviewe

Canopy recovery after drought dieback in holm-oak Mediterranean forests of Catalonia (NE Spain)

Climate change is likely to produce more frequent and longer droughts in the Mediterranean region, like that of 1994, which produced important changes in the Quercus ilex forests, with up to 76% of the trees showing complete canopy dieback. At the landscape level, a mosaic of responses to the drought was observed, linked to the distribution of lithological substrates. Damage to the dominant tree species (Q. ilex) and the most common understorey shrub (Erica arborea) was more noticeable on the compact substrates (breccia) than on the fissured ones (schist). This result was consistent with observations documenting deeper root penetration in schist than in breccia materials, allowing the plants growing on fissured substrates to use water from deeper soil levels. Smaller plants were more vulnerable to drought than larger plants in the trees, but not in the shrubs. Overall, Q. ilex was more affected than E. arborea. The resilience of the system was evaluated from the canopy recovery 1 year after the episode. Stump and crown resprouting was fairly extensive, but the damage pattern in relation to substrate, plant size, and species remained similar. The effect of recurrent drought episodes was studied on vegetation patches of Q. ilex located on mountain slopes and surrounded by bare rock. We observed that plants that resprouted weakly after a previous drought in 1985 were more likely to die or to produce poor regeneration in 1995 than plants that had resprouted vigorously. Vegetation patches located on the lower part of the slope were also less damaged than patches situated uphill. The study provides evidence of relevant changes in forest canopy as a consequence of extreme climate events. The distribution of this effect across the landscape is mediated by lithological substrate, causing patchy patterns. The results also support the hypothesis that recurrent droughts can produce a progressive loss of resilience, by depleting the ability of surviving plants to regenerat

Polymorphism in Bi-based perovskite oxides: a first-principles study

Under normal conditions, bulk crystals of BiScO$_3$ , BiCrO$_3$, BiMnO$_3$, BiFeO$_3$, and BiCoO$_3$ present three very different variations of the perovskite structure: an antipolar phase, a rhombohedral phase with a large polarization along the space diagonal of the pseudocubic unit cell, and a supertetragonal phase with even larger polarization. With the aim of understanding the causes for this variety, we have used a genetic algorithm to search for minima in the surface energy of these materials. Our results show that the number of these minima is very large when compared to that of typical ferroelectric perovskites like BaTiO$_3$ and PbTiO$_3$ , and that a fine energy balance between them results in the large structural differences seen. As byproducts of our search we have identified charge-ordering structures with low energy in BiMnO$_3$ , and several phases with energies that are similar to that of the ground state of BiCrO$_3$. We have also found that a inverse supertetragonal phase exists in bulk, likely to be favored in films epitaxially grown at large values of tensile misfit strain

De "Paraules al vent" a "La Fàbrica": creació, evolució i publicació dels primers poearis de Miquel Martí i Pol

Aquest article té per objecte resseguir la trajectòria de creació i publicació dels primers llibres de Miquel Martí i Pol i mostrar el canvi d’orientació poètica de la seva obra a partir de 1957 i fins a 1961. El «canvi de rumb» experimentat, tal com l’anomenava el mateix autor, va comportar el trànsit de la introspecció dels primers reculls, inclosa l’evolució de la seva crisi religiosa, cap a la «poesia social» d’El poble i La fàbrica.The aim of this article is to analyze the creation and publication process of Miquel Martí i Pol’s early books, as well as to show the change of poetic orientation of his work from 1957 to 1961. This change of direction (in the poet’s words) lead him from the introspection of his first poems to the «social poetry» of El poble and La fàbrica, a path marked by his crisis of religious faith