Bioactivity of wollastonite/aerogels composites obtained from a TEOS-MTES matrix

Organic-inorganic hybrid materials were synthesized by controlled hydrolysis of tetraethoxysilane (TEOS), methyltrimethoxysilane (MTES), synthetic wollastonite powders and polydimethylsiloxane (PDMS) in an ethanol solution. Aerogels were prepared from acid hydrolysis of TEOS and MTES with different volume ratio in ethanol, followed by addition of wollastonite powder and PDMS in order to obtain aerogels with 20 wt% of PDMS and 5 wt% of CaO of the total silica. Finally, when the wet gels were obtained, they were supercritically dried at 260°C and 90 bar, in ethanol. In order to obtain its bioactivity, one method for surface activation is based on a wet chemical alkaline treatment. The particular interest of this study is that we introduce hybrid aerogels, in a 1 M solution of NaOH, for 30 s at room temperature. We evaluate the bioactivity of TEOS-MTES aerogel when immersed in a static volume of simulated body fluid (SBF). An apatite layer of spherical-shaped particles of uniform size smaller than 5 microns is observed to form on the surface of the aerogels after 25 days soaking in SBF.Ministerio de Ciencia e Innovación MAT2005-01583Junta de Andalucía TEP 79

Verbal Memory and IQ Predict Adaptive Behavior in Children and Adolescents with High-Functioning Autism Spectrum Disorders

Adaptive deficits are commonly found in high functioning autism spectrum disorders (HF-ASD) despite of cognitive potential. Most studies have focused on the relationships between adaptive behavior and intellectual quotient (IQ) and have used correlations to study relationships between them. Few studies have analyzed cognitive variables other than IQ as potential predictors of adaptive behavior in HF-ASD using regression methods. This study aimed to analyze the impact of several cognitive variables on adaptive behavior in a sample of children and adolescents with HF-ASD. METHODS: Sample included 16 child and adolescent boys with HF-ASD (age between 7-17 years). Cognitive assessment included measures of general intelligence, visual memory, verbal memory, working memory and problem solving/flexibility tests. Vineland Adaptive Behavior Scales (VABS) was used to evaluate adaptive behavior. To establish the predictive capacity of the cognitive variables for adaptive functioning, linear regression models were fitted for each adaptive domain using a stepwise method. RESULTS: Verbal memory and IQ emerged as the main independent predictors for VABS adaptive scores. The 41% of the variance in Communication was predicted by IQ. The 35% of the variance in Daily Living Skills was predicted by verbal memory. Almost half of the variance in Socialization was predicted by both, verbal memory and IQ (49%). No other cognitive functions were associated with adaptive scores. CONCLUSIONS: The results highlight the strong impact of IQ and verbal memory on adaptive behavior in HF-ASD patients. These findings could contribute to identify potential targets of intervention

Comportamiento aerodinámico de barreras cortavientos 1

El trabajo presenta resultados de la exploración del campo de velocidades en estelas de distintos modelos de barreras porosas, con vistas a suposible utilización para proteger plantaciones o zonas habitadas de los efectos perniciosos del viento. Los ensayos se han hecho en túnel aerodinámico y, para las medidas, se ha utilizado un anemómetro de hilo caliente. Se ha medido: la velocidad media temporal, el nivel de turbulencia y, en algunos casos, el transporte turbulento y la inclinación del vector velocidad, en cuatro secciones distintas corriente abajo de cada barrera. El trabajo está dividido en ocho capítulos. En el primero se discute la posible utilidad de las barreras en agricultura. En el segundo se revisan ciertas características de las estelas turbulentas de diferentes obstáculos,con el fin de contrastar los resultados obtenidos con otros análogos. En el capítulo tercero se describen los métodos de medida. El cuarto presenta el grueso de los resultados, y los cuatro siguientes: la influencia del número de Reynolds, rugosidad del suelo, perfil del viento incidente y presencia de las paredes y techo del túnel, respectivamente. Los ensayos muestran que los perfiles de velocidades correspondientes a secciones situadas a cierta distancia de la barrera (mayor de seis a ocho veces la altura de ésta) se asemejan a los de un semichorro de baja velocidad que descarga paralelamente a una corriente más rápida. Los perfiles próximos y las condiciones iniciales del semichorro dependen de la configuración de la barrera. El modelo del semichorro equivalente permite calcular las características de la estela a distancias mayores que las que es posible reproducir en los experimentos. Por otra parte, sugiere ciertas modificaciones de la forma de la barrera para aumentar la longitud de la zona protegida del viento. La rugosidad del suelo y la existencia de perfiles de viento distintos del uniforme y más ajustados a la realidad, contribuyen a disminuir la longitud de la zona protegida. Esta observación está de acuerdo con los resultados de otros autores. Se observa que el nivel de turbulencia es muy sensible a las características geométricas de la barrera, lo que sugiere la posibilidad de controlar la capa límite sobre el terreno y, por tanto, el transporte de calor y masa en provecho de la productividad de cultivo. El trabajo que se presenta es parte de un programa más amplio, que tiene por objeto transmitir tecnología avanzada a ciertos dominios de interés para la agricultura y la industria

The history of star formation and mass assembly in early-type galaxies

We define a volume limited sample of over 14,000 early-type galaxies (ETGs) selected from data release six of the Sloan Digital Sky Survey. The density of environment of each galaxy is robustly measured. By comparing narrow band spectral line indices with recent models of simple stellar populations (SSPs) we investigate trends in the star formation history as a function of galaxy mass (velocity dispersion), density of environment and galactic radius. We find that age, metallicity and alpha-enhancement all increase with galaxy mass and that field ETGs are younger than their cluster counterparts by ~2 Gyr. We find negative radial metallicity gradients for all masses and environments, and positive radial age gradients for ETGs with velocity dispersion over 180 km/s. Our results are qualitatively consistent with a relatively simple picture for ETG evolution in which the low-mass halos accreted by a proto-ETG contained not only gas but also a stellar population. This fossil population is preferentially found at large radii in massive ETGs because the stellar accretions were dissipationless. We estimate that the typical, massive ETG should have been assembled at z < 3.5. The process is similar in the cluster and the field but occurred earlier in dense environments.Comment: 5 pages, 2 figures. Submitted to MNRA

The link between the Star Formation History and [alpha/Fe]

(Abridged) The abundance ratios between key elements such as iron and alpha-process elements carry a wealth of information on the star formation history (SFH) of galaxies. So far, simple chemical evolution models have linked [alpha/Fe] with the SFH timescale, correlating large abundance ratios with short-lived SFH. We provide an empirical correlation between [alpha/Fe] (measured from spectral indices) and the SFH (determined via a non-parametric spectral-fitting method). We offer an empirical version of the iconic outline of Thomas et al. (2005), relating star formation timescale with galaxy mass, although our results suggest, in contrast, a significant population of old (>10Gyr) stars even for the lowest mass ellipticals. In addition, the abundance ratio is found to be strongly correlated with the time to build up the stellar component, showing that the highest [alpha/Fe] (>+0.2) are attained by galaxies with the shortest half-mass formation time (<2Gyr), or equivalently, with the smallest (<40%) fraction of populations younger than 10Gyr. These observational results support the standard hypothesis that star formation incorporates the Fe-enriched interstellar medium into stars, lowering the high abundance ratio of the old populations.Comment: 5 pages, 2 figures. Accepted for publication in MNRAS Letter

Activos, productos y mercados financieros: entre todos y para todos

Fac. de Ciencias Económicas y EmpresarialesFALSEsubmitte

Prediction equations of skinfold in children of primary school

El objetivo de este trabajo es crear ecuaciones que estimen las medidas de los pliegues cutáneos para escolares de 6 a 13 años de edad. Como resultado se obtuvieron catorce ecuaciones que estiman algunos pliegues cutáneos. Las ecuaciones se validaron con muestras aleatorias de 479 niñas y 541 niños del estado de Puebla y otras 2 muestras aleatorias del estado de Veracruz con 155 niñas y 146 niños respectivamente; las mediciones directas se realizaron con la metodología y unidades ISAK (International Society for the Advancement of Kinanthropometry)The aim of this paper is to create equations that predict the skinfold measures for school children 6 to 13 years old. Fourteen resulting equations were derived to estimate some measures of skinfold. The equations were validated with random samples of 479 girls and 541 boys in the state of Puebla and 2 other random samples of the state of Veracruz with 155 girls and 146 boys respectively; direct measurements were performed with the methodology and units ISAK (International Society for the Advancement of Kinanthropometr

SPIDER VII - Revealing the Stellar Population Content of Massive Early-type Galaxies out to 8Re

Radial trends of stellar populations in galaxies provide a valuable tool to understand the mechanisms of galaxy growth. In this paper, we present the first comprehensive analysis of optical-optical and optical-NIR colours, as a function of galaxy mass, out to the halo region (8Re) of early-type galaxies (ETGs). We select a sample of 674 massive ETGs (M*>3x10^10MSun) from the SDSS-based SPIDER survey. By comparing with a large range of population synthesis models, we derive robust constraints on the radial trends in age and metallicity. Metallicity is unambiguously found to decrease outwards, with a measurable steepening of the slope in the outer regions (Re<R<8Re). The gradients in stellar age are found to be more sensitive to the models used, but in general, the outer regions of ETGs feature older populations compared to the cores. This trend is strongest for the most massive galaxies in our sample (M*>10^11MSun). Furthermore, when segregating with respect to large scale environment, the age gradient is more significant in ETGs residing in higher density regions. These results shed light on the processes leading from the formation of the central core to the growth of the stellar envelope of massive galaxies. The fact that the populations in the outer regions are older and more metal-poor than in the core suggests a process whereby the envelope of massive galaxies is made up of accreted small satellites (i.e. minor mergers) whose stars were born during the first stages of galaxy formation.Comment: 20 pages, 13 figures, 10 tables. Accepted for publication in MNRA