Non-singular radiation cosmological models

In this paper we analyse the possibility of constructing singularity-free inhomogeneous cosmological models with a pure radiation field as matter content. It is shown that the conditions for regularity are very easy to implement and therefore there is a huge number of such spacetimes.Comment: 13 pages, LaTex, ws-mpla, to appear in Modern Physics Letters

Exterior Differential System for Cosmological G2 Perfect Fluids and Geodesic Completeness

In this paper a new formalism based on exterior differential systems is derived for perfect-fluid spacetimes endowed with an abelian orthogonally transitive G2 group of motions acting on spacelike surfaces. This formulation allows simplifications of Einstein equations and it can be applied for different purposes. As an example a singularity-free metric is rederived in this framework. A sufficient condition for a diagonal metric to be geodesically complete is also provided.Comment: 27 pages, 0 figures, LaTeX2e, to be published in Classical and Quantum Gravit

Effect of being the organizer of a Handball Worl Championship in team perfomance

Cuando un equipo actúa como local parece tener cierta ventaja. Este hecho se denomina home advantage (HA) y ha sido muy estudiado en competiciones de liga, pero poco en competiciones de sede única. Se analizaron 4.340 partidos disputados en todos los Campeonatos del Mundo de balonmano disputados hasta 2011. Las variables registradas fueron: partidos ganados, empatados, perdidos, número goles marcados y recibidos y sexo de los competidores. La HA en los Campeonatos del Mundo de balonmano es de 67,9±0,23 para la categoría masculina y de 71,2±0,27 para la femenina. Existe una asociación entre la HA, los puntos obtenidos y la clasificación final del equipo.When a team plays at home seems to get some advantage. This effect is called home advantage (HA) and has been widely studied in league competitions, but little in competitions in a single venue. 4.340 games played in all Handballl World Championships since 1936 to 2011 were analyzed. The variables registered were games won, games drawn, games lost, the number of goals scored and goals against and the gender of the competitors. The HA (mean±sd) in the World Handball Championships is 67.9±0.23, for the male category and 71.2±0.27 for the female. A significant association exists between HA, the points obtained in a competition and the final classification of a team

Rational exploitation of a granite outcrop

[Abstract] This piece analizes the possibilities of mining exploitation in a little outcrop of rOSfl granite. The zone has been researched, recognizing the main structural discontinuities, and characterizing the rock mass by the geomechanic classificationofBARTON. Two core drilling have been made to study the evolution ofthe deeper bed. The volume ofthe bed has been calculated by geometric calculation in the researched area. The theories ofCASTAING and RABU have been developed to estimate the useful volume of the bed for a minimum block size of 1 m3. We have implerríented a computer program in base ofEXCEL 4.0. The result is a useful volume of 51.67 %. By the application of the reduction coefficients ofsterility and irregularity, the maximum estimated efficiency of the exploitation is 33 %

Thermodynamic analysis of unimer-micelle and sphere-to-rod micellar transitions of aqueous solutions of sodium dodecylbenzenesulfonate

Temperature dependence of specific conductivity of sodium dodecylbenzenesulfonate (NaDBS) aqueous solutions was analyzed. Two breaks on the plot appeared for all temperature, which suggest two micellar transitions. This has been corroborated by surface tension measurements. The first transition concentration occurs at the critical micelle concentration (CMC), whilst the second critical concentration (so-called transition micellar concentration, TMC) is due to a sphere-to-rod micelles transition. The dependence of CMC and TMC on the temperature allows the computation of the corresponding thermodynamic functions: Gibbs free energy, enthalpy and entropy changes. For the CMC, enthalpy and entropy increments were found that decrease with the temperature values. However, an anomalous behavior was obtained for the TMC, where both ΔS0 and ΔH0 values raised with the temperature increase. However, for both transitions, an (enthalpy + entropy) compensation is observed. These results will be compared with similar systems reported in the literature

Diagnosis of bronchial hyperresponsiveness in sport by PC20 value

En este trabajo se exponen los criterios de positividad del Comité Olímpico Internacional versus a la Sociedad Española de Neumología y Cirugía Torácica. Participaron en este estudio ochenta deportistas de alto rendimiento, realizando una historia clínica, una espirometría de reposo y un test de metacolina. Se analiza la sensibilidad y especificidad del test de metacolina mediante curvas ROC. El comité Internacional antidopaje (WADA) requiere que la disminución sea con un PC20 < a 4mg/ml, mientras que para la práctica clínica este descenso debe presentar un PC20 < 8mg/ml. Los resultados fueron: 25% tuvieron un PC20 > de 8mg/ml; el 61% obtuvieron un PC20 < 4mg/ml y un 14% presentaron un PC20 entre 4 y 8mg/ml, correspondiendo el mejor punto de corte a PC20 de 7,6mg/ml con especificidad de 98,3 y sensibilidad de 100%. Se tendría que determinar los mismos criterios para el diagnóstico de los deportistas y los que no lo son.In this work criteria of the International Olympic Committee versus the Spanish Society of Pneumology and Thoracic Surgery are exposed. A study was conducted in eighty high performance athletes of several sports . Who underwent a medical history, resting spirometry and a methacholine challenge test. You get the sensitivity and specificity of methacholine challenge test using Receiver Operating Curves (ROC curves). International anti-doping Committee requires that the decline is a PC20 < 4mg/ml, while clinical practice this fall must submit a PC20 < 8mg/ml. Twenty five percent of those studied had a PC20 > of 8mg/ml, 61% had a PC20 < 4mg/ml and 14% had a 4 to 8mg/ml PC20. The best cutoff point was found for a PC20 of 7.6 mg/ml with a specificity of 98.3 and a sensitivity of 100%. It would have to determine the same criteria for positive diagnosis of athletes and those who are not

Optimización del proceso kraft en maderas de Eucalyptus globulus

Se ha estudiado en maderas de E. globulus como afecta el factor H y la carga de álcali activo en cocción sobre la facilidad de la deslignificación, el contenido en carbohidratos y la eliminación de extractos de las pastas crudas obtenidas a un mismo nivel de lignina residual. Los resultados obtenidos mostraron que trabajar con bajas cargas de álcali activo y temperaturas en cocción más elevadas, aumenta el rendimiento de pasta en cocción y eliminan más sitosterol. Sin embargo, las blancuras más altas se obtienen trabajando con alta carga de álcali activo. Los xilanos son los compuestos más sensibles a la alta carga de álcali y se eliminan en gran extensión. Las pastas obtenidas con bajo álcali residual en cocción tienen mejor estallido y tracción pero peor drenabilidad, volumen, opacidad y porosidad.___________________________________This paper studies how H factor and active alkali loads in cooking affect E. globulus woods with regard to ease of delignification, carbohydrate content or removal of extractives. The results obtained demonstrated that working with low alkali loads and higher cooking temperatures increase pulp production and remove greater amounts of sitosterol. However, the greatest brightness is achieved by working with a high active alkali load. Xylans are the most sensitive compounds to high alkali loads and to a large extent are removed. Pulp produced with low residual alkali in the cooking stage has better burst index and tensile strength, but lower dewatering, bulk, opacity and air permeability

Ecología, cariología y anatomía de la planaria Pentacoelum hispaniense Sluys, 1989 (Platyhelmintes, Tricladida)

On the basis of recently discovered new populations of the triclad flatworm Pentacoelum hispaniense new data are detailed on the ecology, reproduction, karyology, and anatomy of the species, including the first description of the external appearance of living specimens. Living animals show three refringent patches on the dorsal surface of which the nature and function remain unknown. The diploid chromosome complement consists of 14 chromosomes. The species appears to be restricted to relatively warm, lowland bodies of water, where it may be found in heterogeneous habitats. The species reproduces only sexually through the production of cocoons. This study presents the first record of a digenean flatworm parasitizing a marine triclad in the form of a metacercaria.Basándonos en las nuevas poblaciones descubiertas del tríclado Pentacoelum hispaniense aportamos nuevos datos ecológicos, reproductivos, cariológicos y anatómicos de la especie, incluyendo la primera descripción de la anatomía externa. Estos animales presentan tres manchas dorsales refringentes de naturaleza y función desconocidas. El complemento cromosómico diploide consta de 14 cromosomas. La especie parece restringida a masas de agua relativamente cálidas de tierras bajas, donde puede ser encontrada en hábitats heterogéneos. Su reproducción es exclusivamente sexual mediante la producción de capullos. El presente estudio recoge la primera cita de un digenio parasitando un tríclado del grupo de las marícolas, en el estadio de metacercaria