Prime numbers, quantum field theory and the Goldbach conjecture

Motivated by the Goldbach conjecture in Number Theory and the abelian bosonization mechanism on a cylindrical two-dimensional spacetime we study the reconstruction of a real scalar field as a product of two real fermion (so-called \textit{prime}) fields whose Fourier expansion exclusively contains prime modes. We undertake the canonical quantization of such prime fields and construct the corresponding Fock space by introducing creation operators $b_{p}^{\dag}$ --labeled by prime numbers $p$-- acting on the vacuum. The analysis of our model, based on the standard rules of quantum field theory and the assumption of the Riemann hypothesis, allow us to prove that the theory is not renormalizable. We also comment on the potential consequences of this result concerning the validity or breakdown of the Goldbach conjecture for large integer numbers.Comment: 20 pages in A4 format, 2 figure

The Rosenberg Self-Esteem Scale: Translation and Validation in University Students

El propósito de esta investigación ha sido traducir al español y analizar las propiedades psicométricas de la escala de autoestima de Rosenberg (RSES) en una muestra de estudiantes universitarios. El análisis factorial confirmatorio confirmó que el modelo que mejor se ajusta a los datos tanto en la muestra total como en las submuestras de hombres y mujeres tiene una estructura unifactorial con efectos de método en los ítems formulados en positivo. Los resultados indican correlaciones positivas y fuertes entre la autoestima y cinco dimensiones del autoconcepto. Además, la escala ha mostrado niveles satisfactorios de consistencia interna y estabilidad temporal tras un periodo de cuatro semanas. Finalmente, se han obtenido diferencias de género significativas. Estos resultados apoyan el uso de la RSES para evaluar la autoestima en el contexto educativo universitario.The aim of this study was to translate into Spanish and to validate the Rosenberg Self-Esteem Scale (RSES), completed by 420 university students. Confirmatory factor analysis revealed that the model that best fit the data, both in the total sample and in the male and female subsamples, was the one-factor structure with method effects associated with positively worded items. The results indicated high, positive correlations between self-esteem and the five dimensions of selfconcept. The scale showed satisfactory levels of internal consistency and temporal stability over a four-week period. Lastly, gender differences were obtained. These findings support the use of the RSES for the assessment of self-esteem in higher education

Vegetación acuática y helofítica del Sistema Ibérico septentrional, centro de España

Vegetación acuática y helofítica del Sistema Ibérico septentrional, centro de España. En este trabajo, se han reconocido 11 asociaciones y 4 comunidades pertenecientes a las clases fitosociológicas Potametea y Phragmito-Magnocaricetea. El Sistema Ibérico septentrional constituye un límite meridional para comunidades de óptimo centro-europeo -Caricetum rostratae, Caricetum vesicariae y Comunidad de Sparganium emersum-, así como un límite oriental para comunidades de óptimo atlántico -Ranunculetum omiophylli, Galio broteriani-Caricetum broterianae, Glycerio declinatae-Eleocharitetum-palustris, Glycerio declinatae-Oenanthetum crocatae y Oenantho crocatae-Phalaridetum arundinaceae-

Социокультурный компонент содержания обучения как одно из средств повышения мотивации изучения иностранных языков

Показана важность мотивации при усвоении иностранного языка. Установлено, что использование социокультурного компонента обучения отражает реальные потребности обучающихся в получении межпредметного знания, связанного с организацией культурных связей с носителями языка. Делается вывод о том, что задания, цель которых заключается в формировании социокультурной компетенции, являются средством повышения мотивации изучения иностранного языка, в частности, благодаря своей исследовательско-поисковой направленности

Effect of band-filling and structural distortions on the Curie temperature of Fe-Mo double perovkites

By means of high resolution neutron powder diffraction at low temperature we have characterized the structural details of $\rm La_{x}Sr_{2-x}FeMoO_6$ ($0\leq {\rm x}\leq 0.5$) and $\rm Ca_{x}Sr_{2-x}FeMoO_6$ ($0\leq {\rm x}\leq 0.6$) series of compounds. This study reveals a similar variation of the mean bond-angle \FeOMo in both series. In contrast, the mean bond-distance \FeMoO\ increases with La but not with Ca substitution. Both series also present a different evolution of the Curie temperature ($T_C$), which raises in the La series and slightly decreases in the Ca one. We thus conclude that the enhancement of $T_C$ in the La series is due to the electron filling of the conduction band and a concomitant rising of the density of states at the Fermi level.Comment: Revtex, 4 Journal pages, 2 figures, 1 tabl

Pressed and sintered AISI 4140 PM low alloy steel from gas atomised powders

This paper is based on a presentation at Euro PM 2012 organised by EPMA in Basel, Switzerland on 16–19 September 2012In conventional PM of low alloy steels various alloying routes are used (fully prealloyed powders, diffusion alloying, elemental powders), but always using powders that allow uniaxial pressing, i.e. acceptable compressibility and flow. Fully prealloyed gas atomised powders (including carbon content) have never been an option because their small size. These powders need to be granulated before being uniaxially pressed and the binder used in the granulating process must be eliminated in the first steps of the sintering cycle. Such a processing route is proposed and initial results presented. A potential advantage of the process is that a low particle size can activate the sintering performance, bringing energy and cost savings over the full process cycle.Publicad

Actualidad editorial de la historia conceptual

El artículo se incluye dentro de la revista en un dossier titulado 'Filosofía de la historia e historia conceptual II'. En consonancia con este epígrafe y bajo el lema de 'Actualidad editorial de la historia conceptual' se agrupan varias reseñas de publicaciones centradas en esta disciplina. En primer lugar, Lorena Rivera León se ocupa del monográfico 'Teoría y práctica de la historia conceptual' publicado por la revista 'Isegoría', nº 37 (2007), así como del volumen 'Teorías y prácticas de la historia conceptual' compilado por Faustino Oncina Coves y aparecido en CSIC-Plaza y Valdés en 2008. En segundo término, María G. Navarro presta atención a 'Conceptos. Revista de investigación graciana', nº 5 (2008). Por último, José Manuel Sánchez Fernández se detiene en el libro 'Historia conceptual, Ilustración y modernidad', escrito por Faustino Oncina Coves, que vio la luz en la editorial Anthropos en 2009

Diffeomorphisms, Noether Charges and Canonical Formalism in 2D Dilaton Gravity

We carry out a parallel study of the covariant phase space and the conservation laws of local symmetries in two-dimensional dilaton gravity. Our analysis is based on the fact that the Lagrangian can be brought to a form that vanishes on-shell giving rise to a well-defined covariant potential for the symplectic current. We explicitly compute the symplectic structure and its potential and show that the requirement to be finite and independent of the Cauchy surface restricts the asymptotic symmetries.Comment: 14 pages, latex with psfig macro, one figur

On The Reduced Canonical Quantization Of The Induced 2D-Gravity

The quantization of the induced 2d-gravity on a compact spatial section is carried out in three different ways. In the three approaches the supermomentum constraint is solved at the classical level but they differ in the way the hamiltonian constraint is imposed. We compare these approaches establishing an isomorphism between the resulting Hilbert spaces.Comment: 17 pages, plain LaTeX. FTUV/93-15, IFIC/93-10, Imperial-TP/93-94/1