Pinning of domain walls in thin ferromagnetic films

We present a quantitative investigation of magnetic domain-wall pinning in thin magnets with perpendicular anisotropy. A self-consistent description exploiting the universal features of the depinning and thermally activated subthreshold creep regimes observed in the field-driven domain-wall velocity is used to determine the effective pinning parameters controlling the domain-wall dynamics: The effective height of pinning barriers, the depinning threshold, and the velocity at depinning. Within this framework, the analysis of results published in the literature allows for a quantitative comparison of pinning properties for a set of magnetic materials in a wide temperature range. On the basis of scaling arguments, the microscopic parameters controlling the pinning: The correlation length of pinning, the collectively pinned domain-wall length (Larkin length), and the strength of pinning disorder are estimated from the effective pinning and the micromagnetic parameters. The analysis of thermal effects reveals a crossover between different pinning length scales and strengths at low reduced temperatures.Fil: Jeudy, V.. Université Paris Sud; Francia. Centre D'etudes de Saclay; Francia. Centre National de la Recherche Scientifique; FranciaFil: Díaz Pardo, R.. Université Paris Sud; Francia. Centre D'etudes de Saclay; Francia. Centre National de la Recherche Scientifique; FranciaFil: Savero Torres, W.. Université Paris Sud; Francia. Centre D'etudes de Saclay; Francia. Centre National de la Recherche Scientifique; FranciaFil: Bustingorry, Sebastián. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Kolton, Alejandro Benedykt. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentin

Depresión en personas mayores: Aplicación del método de Bayes

En el presente trabajo se realiza, en primer lugar, una descripción de la sintomatología depresiva en general y en la población de personas mayores en particular. A su vez, se exponen una serie de variables que podrían estar relacionadas con la presencia o ausencia de esta sintomatología. Estas variables son edad, género, estado civil, deterioro cognitivo, dependencia física, estilo de afrontamiento y bienestar psicológico. A partir de estas variables, se realiza un análisis probabilístico empleando el Método de Bayes, herramienta novedosa en el campo de la investigación psicológica. La investigación se llevó a cabo en 66 sujetos mayores de 65 años, y los instrumentos utilizados para recabar información fueron la Prueba de Vocabulario de la Escala de lnteligencia de Wechsler para Adultos- lll, la Escala de Depresión Geriátrica de Yesavage, el Cuestionario de Afrontamiento de Estrés, las Escalas de Bienestar Psicológico de Ryff, el Mini Examen Cognoscitivo y el fndice de Barthel. Los resultados reflejan que, para nuestra muestra, no existiría relación entre la sintomatología depresiva y las variables de género, edad, estado civil e independencia física. Por el contrario, la ausencia de síntomas depresivos muestra una relación directa y positiva tanto con la variable deterioro cognitivo como el estilo de afrontamiento positivo (centrado en la focalización de problemas). Finalmente, el bienestar psicológico parece estar fuertemente ligado a la ausencia de sintomatología depresiva

Intervenciones cognitivas en demencias: la musicoterapia

El aumento de envejecimiento de la población tiene múltiples repercusiones, una de ellas es la preocupación por las enfermedades asociadas a las edades avanzadas y los tratamientos a utilizar. Aunque la demencia no es una consecuencia natural del envejecimiento, constituye el trastorno neurológico más frecuente en edades avanzadas. En la actualidad no existe cura para esta patología, sólo tratamientos que intentan demorarla. Las intervenciones cognitivas junto con los fármacos son el tratamiento actual más útil para ralentizar el avance de la demencia. El tratamiento de elección no farmacológico en personas con demencia es la estimulación cognitiva, pero no es el único, otros tratamientos como la musicoterapia llevan más de treinta años utilizándose. Diversos estudios basados en estos tratamientos no farmacológicos muestran resultados favorables, tanto en el mantenimiento del rendimiento cognitivo como en las mejoras en ansiedad y depresió

Exploring the potential of conventional and flash pyrolysis methods for the valorisation of grape seed and chestnut shell biomass from agri-food industry waste

Producción CientíficaResidual biomass is a valuable and growing by-product, but often underutilized. This research aims to investigate the possible strategies for the energetic valorisation of agri-food industry wastes: grape seed and chestnut shell. Pyrolysis thermal process was the selected for this work. Applied to biomass, pyrolysis is a promising method for the simultaneous production of biochar, bio-oil, and gas. Two different pyrolysis processes were conducted: conventional pyrolysis at 750 °C and flash pyrolysis at 750 °C and 850 °C. Flash pyrolysis yielded superior product properties compared to conventional pyrolysis. The gas obtained through flash pyrolysis presented a four-fold higher high heating value due to increased CH4 and H2 content. Bio-oil contains over 90% of polycyclic aromatic hydrocarbons, and calorific value reached up to 32 MJ kg−1 for grape seed, which is 7% more than bioethanol HHV. Biochar can be used both as fuel or as activated carbon precursor due to its high carbon content (91%). Calorific value of chestnut shell biochar (32.7 MJ kg−1), comparable to mineral coals, increased by 72% with respect to the value of this untreated raw material. This work approved the potential of flash pyrolysis as a method to process biomass wastes in a renewable energy scenario.FICYT - Fundación Fomento Asturias Investigación - FEDER (AYUD/2021/51379)Agencia Española de Investigación (PDC2022-133394-I00 y PID2021-124347OB-I00

Aproximación a la Clasificación del Deterioro Cognitivo Leve (DCL) en una muestra de personas mayores institucionalizadas

Actualmente, se considera que el envejecimiento puede clasificarse en tres tipos, el normal, el patológico, donde se encontraría el deterioro cognitivo leve (DCL) y finalmente, el envejecimiento óptimo. A partir de los resultados obtenidos en diferentes pruebas de evaluación neuropsicológica, se plantea como objetivo, establecer grupos diagnósticos de DCL, para describirlos y compararlos. La aplicación de las pruebas se realiza a 20 personas de entre 65 y 94 años, residentes en un centro para mayores de Valencia, España. Los resultados mostraron que, el grupo más frecuente fue el de DCL multidominio no amnésico, y que el menos frecuente el DCL amnésico. Pruebas como el WMS dígitos, la prueba del test Barcelona de evocación categoría, y la de imágenes superpuestas; al igual que las pruebas de funcionamiento cognitivo general, MEC y MoCA, nos demuestran que existen diferencias entre los grupos de DCL

Optimización evolutiva del contenido armónico de un inversor

Este artículo trata sobre la optimización distorsión armónica total (THD) de un convertidor multinivel trifásico con fuentes independientes. Mediante la programación de un algoritmo genético que localice el punto de menor distorsión armónica. Como función objetivo se toma el THD de la tensión de fase, entérminos de los ángulos de conmutación en la modulación. De esta manera el problema se resuelve mediante un enfoque netamente numérico y evitando los problemas asociados a las técnicas de modulación convencionales que utilizan comparaciones con ondas portadoras para obtener una modulación. Los resultados de la optimización fueron probados y validados mediante simulación

Development of Fe2_2O3_3/YSZ ceramic plates for cryogenic operation of resistive-protected gaseous detectors

We present a ceramic material based on hematite (Fe$_2$O$_3$) and zirconia stabilized with yttria at 8% molar (YSZ), that exhibits stable electrical properties with transported charge and that can be tuned to the resistivities necessary to induce spark-quenching in gaseous detectors ($\rho = 10^9-10^{12}$ $\Omega \cdot$cm), from room temperature down to the liquid-vapor coexistence point of nitrogen (77 K). It, thus, allows covering the operating temperatures of most immediate interest to gaseous instrumentation. The ceramics have been produced in a region of mass concentrations far from what has been usually explored in literature: optimal characteristics are achieved for Fe$_2$O$_3$ concentrations of 75%wt (LAr boiling temperature), 35%wt (LXe boiling temperature), and 100%wt (room temperature). The nine order of magnitude enhancement observed for the electrical conductivity of the mixed phases relative to that of pure Fe$_2$O$_3$ is startling, however it can be qualitatively understood based on existing literature. Plates of 4 cm x 4 cm have been manufactured and, prior to this work, operated in-detector at the LXe boiling point (165 K), demonstrating spark-free operation. Preliminary results obtained for the first time on a spark-protected amplification structure (RP-WELL) at around the LAr boiling point (90 K) are now presented, too

Using radio astronomical receivers for molecular spectroscopic characterization in astrochemical laboratory simulations: A proof of concept

We present a proof of concept on the coupling of radio astronomical receivers and spectrometers with chemical reactorsand the performances of the resulting setup for spectroscopy and chemical simulations in laboratory astrophysics. Several experiments including cold plasma generation and UV photochemistry were performed in a 40\,cm long gas cell placed in the beam path of the Aries 40\,m radio telescope receivers operating in the 41-49 GHz frequency range interfaced with fast Fourier transform spectrometers providing 2 GHz bandwidth and 38 kHz resolution. The impedance matching of the cell windows has been studied using different materials. The choice of the material and its thickness was critical to obtain a sensitivity identical to that of standard radio astronomical observations. Spectroscopic signals arising from very low partial pressures of CH3OH, CH3CH2OH, HCOOH, OCS,CS, SO2 (<1E-03 mbar) were detected in a few seconds. Fast data acquisition was achieved allowing for kinetic measurements in fragmentation experiments using electron impact or UV irradiation. Time evolution of chemical reactions involving OCS, O2 and CS2 was also observed demonstrating that reactive species, such as CS, can be maintained with high abundance in the gas phase during these experiments.Comment: Accepted for publication in Astronomy and Astrophysics in September 21, 2017. 16 pages, 18 figure

AT514, a cyclic depsipeptide from Serratia marcescens, induces apoptosis of B-chronic lymphocytic leukemia cells. Interference with the Akt/NF-kB survival pathway

8 páginas, 5 figuras -- PAGS nros. 572-579Clinical treatment of B-cell chronic lymphocytic leukemia (B-CLL) is limited by the progressive drug resistance and nonselectivity of most drugs towards malignant cells. Depsipeptides are present in certain bacteria and display potent antitumor activity. We have studied the effect of the novel cyclodepsipeptide AT514 (serratamolide) from Serratia marcescens on B-CLL cell viability. AT514 induced apoptosis of B-CLL cells from the 21 patients studied, as confirmed by Annexin-V binding and nuclei condensation, with an average IC50 of 13 M. AT514 was effective in those B-CLL cases resistant to fludarabine, but had no effect on normal PBL. AT514 preferentially activated the intrinsic apoptotic pathway, as evidenced by loss of mitochondrial membrane potential, release of cytochrome c and activation of caspase-9 and -3, but not of caspase-8. Importantly, AT514 interfered with phosphatidylinositol-3 kinase and protein kinase C survival signals since it increased the apoptotic effect of LY294002 and BisI inhibitors, and induced Akt dephosphorylation at Ser 473. AT514 also decreased NF-B activity by dramatically reducing the levels of p65 in B-CLL. This was confirmed on functional assays using NF-B-luc-transfected Raji cells and transgenic mice. Our results establish that AT514 induces apoptosis of primary B-CLL cells and could be useful for clinical treatment of this malignancyThis work was supported by grants 08.3/0030.1/2003 from the Comunidad Autónoma de Madrid, SAF2003-00824 from the Ministerio de Ciencia y Tecnología (MCyT), and 01/1183 from Fondo de Investigación Sanitaria (to AGP); and CIDEM Grant 301888 (Generalitat de Catalunya)/Fundació Bosch i Gimpera, to RPT). E Escobar and E López-Martín were supported by fellowships from MCyTPeer reviewe

Male sex pheromone components in Heliconius butterflies released by the androconia affect female choice

Sex-specific pheromones are known to play an important role in butterfly courtship, and may influence both individual reproductive success and reproductive isolation between species. Extensive ecological, behavioural and genetic studies of Heliconius butterflies have made a substantial contribution to our understanding of speciation. Male pheromones, although long suspected to play an important role, have received relatively little attention in this genus. Here, we combine morphological, chemical and behavioural analyses of male pheromones in the Neotropical butterfly Heliconius melpomene. First, we identify putative androconia that are specialized brush-like scales that lie within the shiny grey region of the male hindwing. We then describe putative male sex pheromone compounds, which are largely confined to the androconial region of the hindwing of mature males, but are absent in immature males and females. Finally, behavioural choice experiments reveal that females of H. melpomene, H. erato and H. timareta strongly discriminate against conspecific males which have their androconial region experimentally blocked. As well as demonstrating the importance of chemical signalling for female mate choice in Heliconius butterflies, the results describe structures involved in release of the pheromone and a list of potential male sex pheromone compounds. © 2017 Darragh et al