Effect of acid treatment on the structure of sepiolite.

An ab initio determination of the structure of sepiolite after acid treatment (HCl 0.5 N for 24 h) was carried out using X-ray powder diffraction data. After acid treatment, the sections normal to the a and c axes presented discontinuities, ~2.25 Å wide, parallel to the (010) plane, with no electronic density maxima, thus suggesting that adjacent planes are joined by van der Waals-like residual links. Partial dissolution was detected on both octahedral and tetrahedral sheets, beginning by breaking the ribbons not along the edges, but in the centre, thus creating a 5.20x6.79 Å tunnel along the a axis. By interrupting the tetrahedral sheet, this mechanism changes the phyllosilicate-like nature of the sepiolite to an inosilicate-like structure.Peer reviewe

Evolution of the silicon bottom cell photovoltaic behavior during III-V on Si multi-junction solar cells production

The evolution of the Si bulk minority carrier lifetime during the heteroepitaxial growth of III-V on Si multi-junction solar cell structures via metal-organic vapor phase epitaxy has been analyzed. Initially, the emitter formation produces important lifetime degradation. Nevertheless, a progressive recovery was observed during the growth of the metamorphic GaAsP/Si structure. A step-wise mechanism has been proposed to explain the lifetime evolution observed during this process. The initial lifetime degradation is believed to be related to the formation of thermally-induced defects within the Si bulk. These defects are subsequently passivated by fast-diffusing atomic hydrogen -coming from precursor (i.e. PH3 and AsH3) pyrolysis- during the subsequent III-V growth. These results indicate that the MOVPE environment used to create the III-V/Si solar cell structures has a dynamic impact on the minority carrier lifetime. Consequently, designing processes that promote the recovery of the lifetime is a must to support the production of high-quality III-V/Si solar cells

Analysis of the physiological parameters of young spanish badminton players.

El objetivo de nuestro estudio es conocer las características fisiológicas de los jugadores juveniles de bádminton de alto nivel y comparar los parámetros fisiológicos obtenidos en el laboratorio y durante un partido. Se estudiaron 19 jugadores en edad juvenil, 12 varones y 7 mujeres. A todos se les realizó una prueba de esfuerzo máxima en el laboratorio y mediciones antropométricas. Durante la competición se les monitorizó la frecuencia cardiaca, se analizó la concentración de lactato y se valoró su percepción subjetiva al esfuerzo (RPE). El consumo máximo de oxigeno (VO2 máx.) medio se situaba en 56,07 +/- 6,5 ml/Kg/min. El pico de lactato en 3,18 +/- 1,78 mML-1 y la frecuencia cardiaca máxima media (FC máx.) era de 196,75 +/- 5,29 p. p. m., sin diferencias significativas en ninguno de los parámetros estudiados entre varones y hembras en el laboratorio y la competiciónThe aim of our study was to determine the physiological characteristics of young badminton high level players and to compare the physiological parameters obtained in the laboratory and during a match. Nineteen youth players were studied, 12 men and 7 women. A maximal exercise test in the laboratory was performed to the patients and anthropometrics parameters were taken. Their heart rate, lactate concentration and subjective ratings of perceived exertion were tested during competition. The maximum oxygen consumption (VO2 max) has averaged 56.07 + / - 6.5 ml/Kg/min. The peak lactate 3.18 + / - 1.78 MML-1 and the average maximum heart rate (HR max) was 196.75 + / - 5.29 ppm, no significant differences in any of the parameters studied between males and females or between the laboratory and the competitionEl presente trabajo ha sido realizado gracias a una beca de investigación del Centro de Medicina Deportiva de la Comunidad de Madrid (Orden 3025/2010

A Mathematical Model to Study the Meningococcal Meningitis

AbstractThe main goal of this work is to introduce a novel mathematical model to study the spreading of meningococcal meningitis. Specifically, it is a discrete mathematical model based on cellular automata where the population is divided in five classes: sus- ceptible, asymptomatic infected, infected with symptoms, carriers, recovered and died. It catches the individual characteristics of people in order to give a prediction of both the individual behavior, and whole evolution of population

Cryptographic properties of Boolean functions defining elementary cellular automata

In this work, the algebraic properties of the local transition functions of elementary cellular automata (ECA) were analysed. Specifically, a classification of such cellular automata was done according to their algebraic degree, the balancedness, the resiliency, nonlinearity, the propagation criterion and the existence of non-zero linear structures. It is shown that there is not any ECA satisfying all properties at the same time

Strontium ranelate effect on bone mineral density is modified by previous bisphosphonate treatment

The aim of this study was to evaluate the effect of strontium ranelate (SrR) on bone mineral density (BMD) and boneturnover markers after 1 year of treatment. Additionally, theeffect of SrR in bisphosphonate-naïve patients (BP-naïve)compared to patients previously treated with bisphosphonates (BP-prior) was analyzed. This retrospective study included482 postmenopausal women treated with SrR (2 g/day) for 1year in ten Argentine centers; 41 patients were excludeddue to insufficient data, while 441 were included. Participants were divided according to previous bisphosphonatetreatment in two groups: BP-naïve (n = 87) and BP-prior (n = 350). Data are expressed as mean ± SEM. After 1 year oftreatment with SrR the bone formation markers total alkaline phosphatase and osteocalcin were increased (p < 0.0001),while the bone resorption marker s-CTX was decreased (p =0.0579). Also increases in BMD at the lumbar spine (LS,3.73%), femoral neck (FN, 2.00%) and total hip (TH, 1.54%) [p < 0.0001] were observed. These increments were significant(p < 0.0001) both among BP-naïve and BP-prior patients. Interestingly, the change in BMD after 1 year of SrR treatmentwas higher in BP-naïve patients: LS: BP-naïve = 4.58 ± 0.62%; BP-prior = 3.45 ± 0.28% (p = 0.078). FN: BP-naïve = 2.79 ±0.56%; BP-prior = 2.13 ± 0.29% (p = 0.161). TH: BP-naïve = 3.01± 0.55%; BP-prior = 1.22 ± 0.27% (p = 0.0006). SrR treatmentincreased BMD and bone formation markers and decreaseda bone resorption marker in the whole group, with betterresponse in BP-naïve patients.Fil: Brun, Lucas Ricardo Martín. Universidad Nacional de Rosario. Facultad de Ciencias Médicas. Laboratorio de Biología Ósea; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Galich, Ana M.. Hospital Italiano; ArgentinaFil: Vega, Eduardo. Instituto de la Mujer. Buenos Aires; ArgentinaFil: Salerni, Helena. Consultorios de Investigación Clínica Endocrinológica y del Metabolismo Óseo ; ArgentinaFil: Maffei, Laura. Consultorios Asociados de Endocrinología Dra. Laura Maffei; ArgentinaFil: Premrou, Valeria. Consultorios Asociados de Endocrinología Dra. Laura Maffei; ArgentinaFil: Costanzo, Paulo R. Consultorios de Investigación Clínica Endocrinológica y del Metabolismo Óseo ; ArgentinaFil: Sarli, Marcelo A. Instituto de Investigaciones Metabólicas Dr. Zanchetta; ArgentinaFil: Rey, Paula. Instituto de Investigaciones Metabólicas Dr. Zanchetta; ArgentinaFil: Larroudé, Maria S.. Hospital César Milstein; ArgentinaFil: Moggia, Maria S.. Centro Tiempo; ArgentinaFil: Brance, María Lorena. Universidad Nacional de Rosario. Facultad de Ciencias Médicas. Laboratorio de Biología Ósea; ArgentinaFil: Sánchez, Ariel. Centro de Endocrinología; ArgentinaFil: Grupo Argentino de Estudio del Ranelato de Estroncio. No especifica

Aplicación de autómatas celulares para la descripción de extremos de la precipitación

Ponencia presentada en: IV Congreso de la Asociación Española de Climatología "El Clima entre el Mar y la Montaña", celebrado en Santander del 2 al 5 de noviembre de 2004.[ES]El objetivo de este estudio es comprobar la utilidad de la técnica de Autómatas Celulares (CA) par describir la ocurrencia de extremos de precipitación. Las series temporales de precipitación presentan algunos grados de periodicidad o fluctuaciones debidas a variabilidad climática natural. Una vez filtradas estas componentes mediante técnicas espectrales, aplicamos el modelo propuesto de CA a la serie residual con el fin de caracterizar las rachas secas y húmedas. Este método va a simular dos estados para excesos de precipitación, el estado 0 se corresponde con precipitaciones inferiores al percentil 75, mientras que el estado 1 para las superiores al percentil 75. De forma análoga procedemos para caracterizar rachas de precipitación escasa, consideraremos estado 0 para precipitaciones superiores o igual al percentil 25 y estado 1 para precipitaciones inferiores a dicho percentil. El método lo aplicamos a datos mensuales de precipitación en Salamanca en el periodo 1949 a 2003. Los primeros resultados indican que se consigue aproximar en un 60% la ocurrencia de extremos de precipitación, lo cuál sería de gran interés por su aplicación en planificaciones agrícolas.[EN]The objective of this study is to show the utility of using Cellular Automata (CA) to describe the occurrence of the precipitation extremes. Since the precipitation time series contain some quasi-periodic fluctuations, it is required to filter these components before applying the CA model to characterize the dry and wet spells. The CA used to describe the wet spells consists of two states 0 and 1, which were established according to the threshold of 75 percentile. Similarly, to describe the dry spells we propose a CA with two states 0 and 1 for values higher and lower than 25 percentile respectively. The method is applied to monthly precipitation data of Salamanca (Spain) for the period 1949 to 2003. The first results indicate that the model can capture the occurrence of the precipitation extremes with an 60% of accuracy, therefore this characterization could be useful for agricultural planning.Este trabajo se ha realizado con la subvención del proyecto “Fundación Memoria de D. Manuel Solórzano Barruso” y del proyecto “REN2002-04584-CO-02/CLI” del MCYT

Evidence of telomere attrition and a potential role for DNA damage in systemic sclerosis

[Background]: To investigate the role of cell senescence in systemic sclerosis (SSc), we analyzed telomere shortening (TS) in SSc patients and the effect of targeting DNA damage in the bleomycin model of skin fibrosis. [Results]: Telomere length (TL) in blood leukocytes of 174 SSc patients and 68 healthy controls was measured by Southern blot, and we found shorter age-standardized TL in SSc patients compared to healthy controls. TL was shorter in SSc patients with ILD compared to those without ILD and in anti-topoisomerase I positive compared to anti-centromere positive patients. To analyze the potential role of DNA damage in skin fibrosis, we evaluated the effects of the DNA protective GSE4 peptide in the bleomycin mouse model of scleroderma and the fibrotic response of cultured human dermal fibroblasts. Administration of GSE4-nanoparticles attenuated bleomycin-induced skin fibrosis as measured by Masson’s staining of collagen and reduced Acta2 and Ctgf mRNA expression, whereas transduction of dermal fibroblasts with a lentiviral GSE4 expression vector reduced COL1A1, ACTA2 and CTGF gene expression after stimulation with bleomycin or TGF-β, in parallel to a reduction of the phospho-histone H2A.X marker of DNA damage. [Conclusions]: SSc is associated with TS, particularly in patients with lung disease or anti-topoisomerase I antibodies. Administration of GSE4 peptide attenuated experimental skin fibrosis and reduced fibroblast expression of profibrotic factors, supporting a role for oxidative DNA damage in scleroderma.The authors received financial support from Fondo de Investigación Sanitaria, Instituto de Salud Carlos III (PI19/01129, PI20/00335, and RIER network RD16/0012 RETICS program), co-financed by the European Regional Development Fund (FEDER)

Modelo matemático mediante líneas de espera para el desarrollo de un simulador

El presente proyecto se desarrolló en el marco de la convocatoria a proyectos cofinanciados UBA-UNDAV del año 2012. El objetivo fue proveer una herramienta para la mejora de la gestión del mantenimiento del casco céntrico de una ciudad mediana para lo que se decidió desarrollar un simulador. Con los datos del relevamiento inicial se confeccionó un modelo matemático que consistió en un conjunto de variables aleatorias de acuerdo a la Teoría de Colas para alimentar a un simulador de tránsito. Los datos relevados permitieron elaborar los estimadores (media y varianza muestral) para los parámetros de las variables aleatorias definidas. Este modelo matemático proveyó de lógica al simulador. Éste fue desarrollado para SUMO (Simulation of Urban Mobility) versión 0.25, mediante un script Python que interactúa con la plataforma, más un conjunto de utilitarios entre los que se cuentan editores y graficadores.Sociedad Argentina de Informática e Investigación Operativ

Modelo matemático mediante líneas de espera para el desarrollo de un simulador

El presente proyecto se desarrolló en el marco de la convocatoria a proyectos cofinanciados UBA-UNDAV del año 2012. El objetivo fue proveer una herramienta para la mejora de la gestión del mantenimiento del casco céntrico de una ciudad mediana para lo que se decidió desarrollar un simulador. Con los datos del relevamiento inicial se confeccionó un modelo matemático que consistió en un conjunto de variables aleatorias de acuerdo a la Teoría de Colas para alimentar a un simulador de tránsito. Los datos relevados permitieron elaborar los estimadores (media y varianza muestral) para los parámetros de las variables aleatorias definidas. Este modelo matemático proveyó de lógica al simulador. Éste fue desarrollado para SUMO (Simulation of Urban Mobility) versión 0.25, mediante un script Python que interactúa con la plataforma, más un conjunto de utilitarios entre los que se cuentan editores y graficadores.Sociedad Argentina de Informática e Investigación Operativ