El problema del vellón : su incidencia en la distinta evolución económica de la Castilla y de la Corona de Aragón en el siglo XVII

Las emisiones de vellón provocaron graves problemas en el sistema financiero y crediticio castellano del siglo XVII. El autor analiza, también, las repercusiones de la moneda de cobre sobre las economias valencianas y catalanas y sugiere una investigación sobre los mecanismos de crédito bancario que consiguieron un saneamiento monetario en los reinos periféricosLes emissions de billó van provocar greus problemes en el sistema financer i creditici castella del segle XVII. L'autor analitza, també, les repercussions de la moneda de coure sobre les economies valenciana i catalana i suggereix una recerca sobre els mecanismes de credit bancari que van aconseguir un sanejament monetari en els regnes periferics.The emission of copper coins caused serious problems in the Castilian financial system during the XVII century. The author also analyses the repercussions of this currency in Valencian and Catalan economies. He also suggests a research on the bank credit mechanisrns that achieved a monetary stabilization in the peripherial kingdoms

Green's function approach to Chern-Simons extended electrodynamics: an effective theory describing topological insulators

Boundary effects produced by a Chern-Simons (CS) extension to electrodynamics are analyzed exploiting the Green's function (GF) method. We consider the electromagnetic field coupled to a $\theta$-term in a way that has been proposed to provide the correct low energy effective action for topological insulators (TI). We take the $\theta$-term to be piecewise constant in different regions of space separated by a common interface $\Sigma$, to be called the $\theta$-boundary. Features arising due to the presence of the boundary, such as magnetoelectric effects, are already known in CS extended electrodynamics and solutions for some experimental setups have been found with specific configuration of sources. In this work we illustrate a method to construct the GF that allows to solve the CS modified field equations for a given $\theta$-boundary with otherwise arbitrary configuration of sources. The method is illustrated by solving the case of a planar $\theta$-boundary but can also be applied for cylindrical and spherical geometries for which the $\theta$-boundary can be characterized by a surface where a given coordinate remains constant. The static fields of a point-like charge interacting with a planar TI, as described by a planar discontinuity in $\theta$, are calculated and successfully compared with previously reported results. We also compute the force between the charge and the $\theta$-boundary by two different methods, using the energy momentum tensor approach and the interaction energy calculated via the GF. The infinitely straight current-carrying wire is also analyzed

Exact solution of the Schr\"{o}dinger equation for an hydrogen atom at the interface between the vacuum and a topologically insulating surface

When an hydrogen atom is brought near to the interface between $\theta$-media, the quantum-mechanical motion of the electron will be affected by the electromagnetic interaction between the atomic charges and the $\theta$-interface, which is described by an axionic extension of Maxwell electrodynamics in the presence of a boundary. In this paper we investigate the atom-surface interaction effects upon the energy levels and wave functions of an hydrogen atom placed at the interface between a $\theta$-medium and the vacuum. In the approximation considered, the Schr\"{o}dinger equation can be exactly solved by separation of variables in terms of hypergeometic functions for the angular part and hydrogenic functions for the radial part. In order to make such effects apparent we deal with unrealistic high values of the $\theta$-parameter. We also compute the energy shifts using perturbation theory for a particular small value of $\theta$ and we demonstrate that they are in a very good agreement with the ones obtained from the exact solution.Comment: 20 pages, 17 figures, 6 tables, Accepted for publication in the European Physics Journal

The gene transformer-2 of Sciara (Diptera, Nematocera) and its effect on Drosophila sexual development

<p>Abstract</p> <p>Background</p> <p>The gene <it>transformer-2</it>, which is involved in sex determination, has been studied in <it>Drosophila, Musca</it>, <it>Ceratitis</it>, <it>Anastrepha </it>and <it>Lucilia</it>. All these members of Diptera belong to the suborder Brachycera. In this work, it is reported the isolation and characterisation of genes <it>transformer-2 </it>of the dipterans <it>Sciara ocellaris </it>and <it>Bradysia coprophila </it>(formerly <it>Sciara coprophila</it>), which belong to the much less extensively analysed <it>Sciaridae </it>Family of the Suborder Nematocera, which is paraphyletic with respect to Suborder Brachycera.</p> <p>Results</p> <p>The <it>transformer-2 </it>genes of the studied <it>Sciara </it>species were found to be transcribed in both sexes during development and adult life, in both the soma and germ lines. They produced a single primary transcript, which follows the same alternative splicing in both sexes, giving rise to different mRNAs isoforms. In <it>S. ocellaris </it>the most abundant mRNA isoform encoded a full-length protein of 251 amino acids, while that of <it>B. coprophila </it>encoded a protein of 246 amino acids. Both showed the features of the SR protein family. The less significant mRNA isoforms of both species encoded truncated, presumably non-functional Transformer-2 proteins. The comparison of the functional <it>Sciara </it>Transformer-2 proteins among themselves and those of other insects revealed the greatest degree of conservation in the RRM domain and linker region. In contrast, the RS1 and RS2 domains showed extensive variation with respect to their number of amino acids and their arginine-serine (RS) dipeptide content. The expression of <it>S. ocellaris </it>Transformer-2 protein in <it>Drosophila </it>XX pseudomales lacking the endogenous <it>transformer-2 </it>function caused their partial feminisation.</p> <p>Conclusions</p> <p>The <it>transformer-2 </it>genes of both <it>Sciaridae </it>species encode a single protein in both sexes that shares the characteristics of the Transformer-2 proteins of other insects. These proteins showed conserved sex-determination function in <it>Drosophila</it>; i.e., they were able to form a complex with the endogenous <it>Drosophila </it>Transformer protein that controls the female-specific splicing of the <it>Drosophila doublesex </it>pre-mRNA. However, it appears that the complex formed between the <it>Drosophila </it>Transformer protein and the <it>Sciara </it>Transformer-2 protein is less effective at inducing the female-specific splicing of the endogenous <it>Drosophila doublesex </it>pre-mRNA than the <it>Drosophila</it>Transformer-Transformer2 complex. This suggests the existence of species-specific co-evolution of the Transformer and Transformer-2 proteins.</p