Generaciones y semblanzas de la Asturias ilustrada

El present article es refereix a la Il·lustració a Astúries al segle XVIII i els seus màxims representants, tot distingint les generacions a què pertanyen i que podem classificar o dividir entre les anomenades crítica, regalista, de la reforma i política.El presente artículo se refiere a la Ilustración en Asturias en el siglo XVIII y sus máximos representantes, distinguiendo las generaciones a las que pertenecen y que podemos clasificar o dividir entre las llamadas crítica, regalista, de la reforma y política.This paper addresses the subject of the Enlightenment in Asturias in the 18th century and its top representatives, distinguishing the generations to which they belong, which we may classify or divide into the so-called “critical”, “regalist”, “reformist” and “political” categories

Natural inflation in 5D warped backgrounds

In light of the five-year data from the Wilkinson Microwave Anisotropy Probe (WMAP), we discuss models of inflation based on the pseudo Nambu-Goldstone potential predicted in five-dimensional gauge theories for different backgrounds: flat Minkowski, anti-de Sitter, and dilatonic spacetime. In this framework, the inflaton potential is naturally flat due to shift symmetries and the mass scales associated with it are related to 5D geometrical quantities.Comment: 10 pages, 8 figures; matches version to appear in Phys. Rev.

Electronic transport through bilayer graphene flakes

We investigate the electronic transport properties of a bilayer graphene flake contacted by two monolayer nanoribbons. Such a finite-size bilayer flake can be built by overlapping two semiinfinite ribbons or by depositing a monolayer flake onto an infinite nanoribbon. These two structures have a complementary behavior, that we study and analyze by means of a tight-binding method and a continuum Dirac model. We have found that for certain energy ranges and geometries, the conductance of these systems oscillates markedly between zero and the maximum value of the conductance, allowing for the design of electromechanical switches. Our understanding of the electronic transmission through bilayer flakes may provide a way to measure the interlayer hopping in bilayer graphene.Comment: 11 pages, 8 figure

Light elements in stars with exoplanets

It is well known that stars orbited by giant planets have higher abundances of heavy elements when compared with average field dwarfs. A number of studies have also addressed the possibility that light element abundances are different in these stars. In this paper we will review the present status of these studies. The most significant trends will be discussed.Comment: 10 pages, 6 figures. Submitted to the proceedings of IAU symposium 268: Light elements in the universe

Braneworld inflation from an effective field theory after WMAP three-year data

In light of the results from the WMAP three-year sky survey, we study an inflationary model based on a single-field polynomial potential, with up to quartic terms in the inflaton field. Our analysis is performed in the context of the Randall-Sundrum II braneworld theory, and we consider both the high-energy and low-energy (i.e. the standard cosmology case) limits of the theory. We examine the parameter space of the model, which leads to both large-field and small-field inflationary type solutions. We conclude that small field inflation, for a potential with a negative mass square term, is in general favored by current bounds on the tensor-to-scalar perturbation ratio rs.Comment: 11 pages, 5 figures; references updated and a few comments added; final version to appear in Phys. Rev.

El estudio geográfico de la población en educación primaria

Cuando un niño o un adolescente quieren conocer la situación de la población de su barrio, de su país o del mundo, desean saber cómo viven las personas en esos lugares. Pero con frecuencia lo que le ofrece el sistema escolar es un conjunto de conceptos (densidad, natalidad, mortalidad, migraciones) y una gran cantidad de datos (tasas, índices, números absolutos) que en más de una ocasión le hacen olvidar cuál es su interés por conocer los hechos humanos. El objetivo de este trabajo es mostrar cómo se puede trabajar la población y el espacio geográfico en Educación Primaria (6 a 12 años de edad) y ver una alternativa en el proyecto Gea-Clío

Influence of preparation procedures on the phenolic content, antioxidant and antidiabetic activities of green and black teas

The influence of common tea preparation procedures (temperature, infusion time, consumption time interval and tea bag/loose-leaf) and the type of water used, on the total phenolic content (TPC), the radical scavenging activity and the alpha-glucosidase inhibitory activity were assessed. Higher TPC and antioxidant activity were obtained when using lower mineralized waters. Tea bags also evidenced higher antioxidant activity than loose-leaf samples. Under the same conditions (90 degrees C and five minutes of infusion time) green tea contains almost twice the quantity of polyphenols and the free radical scavenging ability of black tea. In the alpha-glucosidase assay all infusions were active (97-100 %). Furthermore, HPLC allowed to identify some of the polyphenols present in both teas and to monitor their composition change with time. After twenty-four hours, the antioxidant activity was maintained without significant changes, but a small decrease in enzyme inhibition was observed, although this activity was still very high.info:eu-repo/semantics/publishedVersio

Aspects of thermal leptogenesis in braneworld cosmology

The mechanism of thermal leptogenesis is investigated in the high-energy regime of braneworld cosmology. Within the simplest seesaw framework with hierarchical heavy Majorana neutrinos, we study the implications of the modified Friedmann equation on the realization of this mechanism. In contrast with the usual leptogenesis scenario of standard cosmology, where low-energy neutrino data favors a mildly strong washout regime, we find that leptogenesis in the braneworld regime is successfully realized in a weak washout regime. Furthermore, a quasi-degenerate light neutrino mass spectrum is found to be compatible with this scenario. For an initially vanishing heavy Majorana neutrino abundance, thermal leptogenesis in the brane requires the decaying heavy Majorana neutrino mass to be M1 > 10^10 GeV and the fundamental five-dimensional gravity scale 10^12 < M5 < 10^16 GeV, which corresponds to a transition from brane to standard cosmology at temperatures 10^8 < Tt < 10^14 GeV.Comment: 7 pages, 3 figures, a few comments and references added. Final version to appear in Phys. Rev.