The Space of Countably Simple Bounded Functions with Values in a DF-Space

Sin resume

Cristalización de (Sr,Ca)CO, en sistemas difusión-reacción

Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

Conversion of biogenic aragonite into hydroxyapatite scaffolds in boiling solutions

The interaction of Sepia officinalis cuttlefish bone, made of aragonitic CaCO3, with (NH4)2HPO4 boiling solutions produces porous carbonate-bearing hydroxyapatite (Ca10(PO4)6(OH)2) scaffolds with extremely large specific surface area. Percentages of aragonite into hydroxyapatite conversion close to 90% are reached after 10 hours for all the conditions explored, though higher efficiency of the transformation process is achieved by increasing the concentration of the (NH4)2HPO4 solution. The conversion has a pseudomorphic character since it occurs with the accurate preservation of the external shape as well as the primary macro- and microtextural features of the biomineral. Moreover, the mineral replacement transformation is accompanied by a significant increase in surface area, which most likely relates to newly formed porosity. We proposed that this transformation occurs through an interface coupled dissolution–crystallization mechanism, which is continuously promoted by the release of CO2 to the atmosphere. The generation of newly formed porosity would be the consequence of the preservation of the biomineral's external shape, which requires the balance of both molar volume and solubility changes involved in the mineral transformation

El contacto entre las zonas de Ossa Morena y Sudportuguesa. Características y significado de la banda metamórfica de Aracena, en su sector central entre Aroche y Aracena (Huelva)

El contacto entre las zonas de Ossa Morena y Sudportuguesa está subrayado por la banda metamórfica de Aracena. Las características principales de esta región del macizo Ibérico pueden considerarse desde distintos puntos de vista: litológico, estructural, metamórfico, magmático, geoquímica, isotópico y experimental, y así se presentan en este artículo. La banda metamórfica de Aracena está dividida en dos dominios principales: el dominio oceánico está formado por metabasitas derivadas de un MORB (las metabasitas de Acebuches) y por un antiguo prisma de acrección. El dominio continental incluye gneises y migmatitas alumínicos, rocas de silicatos cálcicos, gneises leucocráticos, mármoles, anfibolitas, intrusiones sin/post-tectónicas de noritas ricas en Mg (con afinidad boninítica), así como rocas intrusivas post-tectónicas de composición ácida a básica. Las metabasitas de Acebuches sufrieron, en primer lugar, un metamorfismo de alta temperatura/baja presión que, en la actualidad, presenta un gradiente metamórfico invertido, y que estaba relacionado con un cabalgamiento vergente al SO. El pico térmico asociado a este evento metamórfico muestra un gradiente de edad, de forma que las edades más antiguas han sido obtenidas en el extremo oeste. La mitad inferior de la pila metabasítica de Acebuches fue afectada posteriormente por una deformación milonítica y un retrometamorfismo asociados a la zona de cizalla Sudibérica. Cuatro fases de deformación dúctil han sido definidas en el dominio continental: la fase CD-D1 estuvo relacionada con la generación de pliegues recumbentes de escala kilométrica. La fase CD-D2 se puede asociar a un colapso extensional, y es contemporánea con un metamorfismo de alta temperatura/baja presión que afectó al dominio continental y generó diversos complejos migmatíticos. La fase CD-D3 produjo pliegues simétricos verticales, mientras que la fase CD-D4 dio lugar a cabalgamientos vergentes al sur a los que se asociaron pliegues de propagación.Las principales características de la banda metamórfica de Aracena se interpretan como el resultado de la evolución de un punto triple de tipo fosa-fosa-dorsal. De acuerdo con el modelo propuesto, la interacción entre la dorsal y la zona de subducción dio como resultado la formación de una ventana astenosférica bajo el margen continental cabalgante, lo cual provocó el ascenso de la astenosfera y el consecuente rebote térmico. Esta unión triple migro a lo largo del margen continental hacia el este, lo que generó un cinturón metamórfico de alta temperatura/baja presión en el contacto entre las zonas de Ossa Morena y Sudportuguesa

Carbon and ecological footprints as tools for evaluating the environmental impact of coal mine ventilation air

Coal mines ventilation gases are an important source of methane emissions. Common ventilation systems are designed to ensure safe working conditions in the shafts, leading to huge ventilation gas flow rates. Traditionally, low attention has been paid to such emissions because of their low methane concentration. However, it is necessary to take into account that although the concentration of methane is very low (typically <1%), the volume of air that ventilation systems move is large, and therefore these emissions constitute the largest source of greenhouse gases from underground coal mines. This work proposes the use of ecological and carbon footprints approaches as a tool for determining the relative importance of these emissions in comparison to the other direct and indirect environmental impacts from the coal mining activity. The study has been performed in the main ventilations shafts of the mining company HUNOSA, located at NW Spain (bituminous coal). Results indicate that ventilation air methane is a key fraction of the total emissions of greenhouse gases releases in this activity (60–70%)

A dark energy multiverse

We present cosmic solutions corresponding to universes filled with dark and phantom energy, all having a negative cosmological constant. All such solutions contain infinite singularities, successively and equally distributed along time, which can be either big bang/crunchs or big rips singularities. Classicaly these solutions can be regarded as associated with multiverse scenarios, being those corresponding to phantom energy that may describe the current accelerating universe

Role of prey and intraspecific density dependence on the population growth of an avian top predator

Exploring predator-prey systems in diverse ecosystems increases our knowledge about ecological processes. Predator population growth may be positive when conspecific density is low but predators also need areas with prey availability, associated with competition, which increases the risk of suffering losses but stabilises populations. We studied relationships between European rabbits Oryctolagus cuniculus (prey) and adult eagle owls Bubo bubo (predators) in south-western Europe. We assessed models explaining the predator population growth and stability. We estimated the abundance of rabbits and adult eagle owls during three years in eight localities of central-southern Spain. We explored models including rabbit and adult eagle owl abundance, accounting for yearly variations and including the locality as a random variable. We found that population growth of adult eagle owls was positive in situations with low conspecific abundance and tended to be negative but approaching equilibrium in situations of higher conspecific abundance. Population growth was also positively related to previous summer rabbit density when taking into account eagle owl conspecific abundance, possibly indicating that rabbits may support recruitment. Furthermore, abundance stability of adult eagle owls was positively related to previous winter-spring rabbit density, which could suggest predator population stabilisation through quick territory occupation in high-quality areas. These results exemplify the trade-off between prey availability and abundance of adult predators related to population growth and abundance stability in the eagle owl-rabbit system in south-western Europe. Despite rabbits have greatly declined during the last decades and eagle owls locally specialise on them, eagle owls currently have a favourable conservation status. As eagle owls are the only nocturnal raptor with such dependence on rabbits, this could point out that predators may overcome prey decreases in areas with favourable climate and prey in the absence of superior competitors with similar foraging mode.This study is a partial result from the I + D National Plan Projects CGL2005-02340 and CGL2009-10741, funded by the Spanish Ministry of Science and Innovation and EU-FEDER funds. J. Fernandez-de-Simon benefitted from an FPI scholarship (BES-2006-12562) funded by the Spanish Ministry of Science and Innovation and the European Social Fund.Peer Reviewe

Understanding the stigma of psychosis in ethnic minority groups: A qualitative exploration

Psychosis is a mental health difficulty which is widely stigmatized. The stigma of psychosis can lead to detrimental consequences and cause further distress. The aim of this study was to explore the experience of stigma and discrimination of psychosis from the perspective of service users from ethnic minority backgrounds. A total of 21 semistructured interviews were conducted with service users with psychosis from ethnic minority backgrounds examining their experiences of stigma from psychosis. Qualitative data were analyzed using thematic analysis. Five superordinate themes were identified, “social and cultural context of stigma,” “stigma is a family problem,” “stigma and discrimination within mental health services,” “intrapersonal impacts,” and “managing stigma within relationships.” Stigma is a significant concern for people with psychosis from an ethnic minority background. It is important that stigma and discrimination are appropriately assessed and considered within the care of people from ethnic minority backgrounds

Microscopic NN→NN∗(1440)NN\to NN^{\ast}(1440) transition potential: Determination of πNN∗(1440)\pi NN^{\ast}(1440) and σNN∗(1440)\sigma NN^{\ast}(1440) coupling constants

A $NN\to NN^{\ast}(1440)$ transition potential, based on an effective quark-quark interaction and a constituent quark cluster model for baryons, is derived in the Born-Oppenheimer approach. The potential shows significant differences with respect to those obtained by a direct scaling of the nucleon-nucleon interaction. From its asymptotic behavior we extract the values of $\pi NN^{\ast}(1440)$ and $\sigma NN^{\ast}(1440)$ coupling constants in a particular coupling schemeComment: 15 eps figures, Accepted for publication in Phys. Rev.