Estudio de la migración del deuterio implantado en grafito, para descontaminación de residuos nucleares grafíticos

Los reactores nucleares de 1ª generación han llegado al final de su vida útil y están en proceso de desmantelamiento. A diferencia de los reactores de 2ª generación actualmente en funcionamiento, donde el moderador es el agua, la tecnología utilizada en la época empleaba grandes cantidades de grafito como moderador neutrónico. En Francia, el grafito residual se estima en 23000 toneladas provenientes de nueve centrales de 1ª generación. En España, únicamente existió la central de Vandellòs I con este diseño. Este grafito ha sido sometido a irradiación y a temperaturas medias de 500ºC lo cual tiene varios efectos en el material: por un lado, la desestructuración que se traduce en un aumento de la porosidad y un desmembramiento de los planos de grafeno; por otro, la aparición de nuevas especies debido a las reacciones nucleares que causa el bombardeo de neutrones dentro del reactor. Algunos de los elementos que aparecen son inestables y convierten el grafito en un residuo radiactivo clasificado como de vida larga – puesto que los periodos de desintegración de los radioisótopos exceden los 30 años- y de baja actividad – a tenor de las bajas concentraciones de radioelementos. Las especies que más influyen en esta tipificación son 14C, 36Cl y 3H. El presente trabajo se centra en la eliminación del tritio en estos materiales. Se estudian los efectos de tratamientos térmicos bajo diferentes condiciones (temperatura, tiempo, humedad y tasa de irradiación) mediante el seguimiento del porcentaje de retención de tritio tras recocidos experimentales. Estas medidas se toman sobre muestras de grafito representativas de aquél utilizado en los reactores de la época. En particular, se trabaja con muestras de grafito de calidad nuclear almacenado en la central de Saint-Laurent A2 (Francia), y con HOPG (High Oriented Pyrolytic Graphite). La presencia de tritio se simula mediante implantación iónica de deuterio, isótopo del hidrógeno más ligero que el tritio y carente de actividad radiactiva. La retención, calculada como el cociente entre la cantidad de deuterio restante y la cantidad inicial, se valora por análisis por reacción nuclear (NRA), utilizando el acelerador 4 MV del IPNL (Institut de Physique Nucléaire de Lyon). Los resultados de estas pruebas servirán, en un futuro, para definir las condiciones de un posible tratamiento térmico de descontaminación del grafito nuclear residuo, lo que evitaría el enterramiento en una ubicación geológicamente estable, de todo el volumen de grafito que ya ha sido desalojado; solución esta última, que se presenta a priori más costosa y controvertida

Empirical Evidence of the Metacognitive Model of Rumination and Depression in Clinical and Nonclinical Samples: A Systematic Review and Meta-Analysis

Rumination is considered a cognitive vulnerability factor in the development and maintenance of depression. The metacognitive model of rumination and depression suggests that the development of rumination and its association with depression partly depends on metacognitive beliefs. Two metacognitive beliefs about rumination have been identified: positive beliefs about its utility and negative beliefs about the uncontrollability and its negative social consequences. We conducted a systematic review and meta-analysis aimed: (1) to analyze the associations between metacognitive beliefs and rumination and depression; (2) to test the metacognitive model, using a Two-Stage Structural Equation Modeling approach (TSSEM). Literature search retrieved 41 studies. These 41 studies (N = 10,607) were included in the narrative synthesis and meta-analysis, and 16 studies (N = 4477) were comprised for the TSSEM. Results indicated metacognitive beliefs are associated with rumination and depression. Measures on metacognitive beliefs about rumination indicated that positive beliefs showed moderate associations with rumination (r = 0.50), and low with depression (r = 0.27); whereas negative beliefs showed moderate associations with both rumination (r = 0.46) and depression (r = 0.49). These results were consistent across studies using different instruments to measure metacognitive beliefs, and in both clinical and nonclinical samples. Moreover, results of the TSSEM analyses showed that the metacognitive model had a good fit. In sum, our results are in line with the metacognitive model of rumination and depression, highlighting that metacognitive beliefs are relevant factors to understand why people ruminate and get depressed. Future directions and clinical implications are discussed

Una propuesta de enseñanza de las ecuaciones de primer grado en 1º de E.S.O

Este trabajo es una propuesta de enseñanza para 1º E.S.O. de las ecuaciones de primer grado. Se define el objeto matemático de enseñanza, se hace un estudio del estado de enseñanza-aprendizaje de dicho objeto matemático y de los conocimientos previos y a continuación se describen las razones de ser, campo de problemas, técnicas y tecnologías. Por último se explicita una secuencia didáctica y una propuesta de evaluación.<br /

Revisión sistemática sobre las intervenciones de terapia Oocupacional en mujeres que han sufrido cáncer de mama y presentan alteraciones en las actividades de la vida diaria

Introducción: el cáncer de mama es un problema mundial, en España se diagnostican alrededor de unos 26.000 casos al año. Gracias a los programas de detección precoz y a los avances diagnósticos y terapéuticos ha disminuido la mortalidad y ha incrementado la supervivencia. El objetivo principal del trabajo fue revisar los estudios originales publicados sobre las intervenciones de terapia ocupacional en mujeres que han sufrido cáncer de mama y presentan afectación en las actividades de la vida diaria. Metodología: elaboramos nuestra pregunta de investigación, mediante la pregunta PICO. ¿Qué intervenciones desde terapia ocupacional se realizan a las mujeres que han sufrido cáncer de mama y que además presentan alteraciones en la vida diaria? Se realizó una revisión sistemática de tipo exploratoria en las bases de datos: MEDLINE (a través de Pubmed), Embase, Scopus, Web of Science, Cochrane library y OTsekker. Los artículos incluidos en el trabajo se presentaron mediante tablas resumen. Resultados: se analizaron un total de cinco artículos, de buena, moderada y mala evidencia. Cada artículo realizaba una intervención y tenía unos objetivos diferentes. Pero todos ellos resaltaban las afectaciones en las actividades de la vida diaria así como en las diferentes áreas ocupacionales. Proponiendo así más investigación para poder intervenir desde la terapia ocupacional. Discusión: en nuestra revisión discutimos sobre la falta de investigaciones acerca de las intervenciones de terapia ocupacional en el cáncer de mama ya que se ha observado en los artículos los déficits en las actividades de la vida diaria y en otras áreas de ocupación. Conclusión: Se necesita seguir investigando sobre las intervenciones de terapia ocupacional en mujeres con cáncer de mama ya que el tratamiento que reciben les produce unas secuelas que les afectan en las áreas de ocupación, y ahí la terapia ocupacional podría llegar a intervenir.<br /

A within-person test of the metacognitive model: Daily dynamics between metacognitive beliefs, metacognitive strategies, and negative affect

The metacognitive model of psychological disorders highlights that emotional distress is maintained by metacognitive strategies, which are related to underlying metacognitive beliefs. Considerable empirical evidence has supported the role of metacognitions in psychopathology, but few studies have examined the suggested links between metacognitive beliefs, metacognitive strategies, and symptoms within individuals. Within-person effects provide better empirical tests of theory-based hypotheses derived from clinical models as they relate to change at the individual level. Thus, the current study sought to test central predictions from the metacognitive model at the within-person level using Dynamic Structural Equation Modelling (DSEM). A sample of 222 participants gathered at convenience participated in a 26-day long assessment period where they reported daily measures of metacognitive beliefs, metacognitive strategies, and negative affect. Temporal precedence and bidirectional relations between the variables, and the possible day-to-day and within days mediation role of metacognitive strategies between metacognitive beliefs and negative affect, were tested. When controlling for previous days effects, metacognitions and negative affect (but not metacognitive strategies) predicted each other the next day, showing a reciprocal relationship. However, metacognitive strategies were significant mediators between metacognitions and negative affect within days and day-to-day. Implications and future directions based on these findings are discussed.Funding for open access charge: Universidad de Málaga / CBUA. This study was part of projects funded by the Spanish Government, Spain (grant number PSI2017-83463-R). The funding source only provided financial support for this study and had no further involvement

Machine learning classification–Regression schemes for desert locust presence prediction in western Africa

Producción CientíficaFor decades, humans have been confronted with numerous pest species, with the desert locust being one of the most damaging and having the greatest socio-economic impact. Trying to predict the occurrence of such pests is often complicated by the small number of records and observations in databases. This paper proposes a methodology based on a combination of classification and regression techniques to address not only the problem of locust sightings prediction, but also the number of locust individuals that may be expected. For this purpose, we apply different machine learning (ML) and related techniques, such as linear regression, Support Vector Machines, decision trees, random forests and neural networks. The considered ML algorithms are evaluated in three different scenarios in Western Africa, mainly Mauritania, and for the elaboration of the forecasting process, a number of meteorological variables obtained from the ERA5 reanalysis data are used as input variables for the classification–regression machines. The results obtained show good performance in terms of classification (appearance or not of desert locust), and acceptable regression results in terms of predicting the number of locusts, a harder problem due to the small number of samples available. We observed that the RF algorithm exhibited exceptional performance in the classification task (presence/absence) and achieved noteworthy results in regression (number of sightings), being the most effective machine learning algorithm among those used. It achieved classification results, in terms of F-score, around the value of 0.9 for the proposed Scenario 1.Ministerio de Ciencia, Innovación y Universidades - (project PID2020-115454GB-C21595

A comparative study between olive oil and corn oil on oxidative metabolism

Fats are an important part of diet, but not all lipids have the same structure and chemical properties. Unsaturated fatty acids have one or more double bonds in their structure and can be monounsaturated or polyunsaturated, respectively. Most vegetable oils, such as olive oil and corn oil, contain significant amounts of these fatty acids. The presence of double bonds in the molecule of a fatty acid constitutes vulnerable sites for oxidation reactions generating lipid peroxides, potentially toxic compounds that can cause cellular damage. In response to this oxidative damage, aerobic organisms have intracellular enzymatic antioxidant defense mechanisms. The aim of the present investigation was to study comparatively the effects of control liquid diets, of a defined composition, containing olive oil or corn oil as a lipid source respectively of monounsaturated and polyunsaturated fatty acids, on the oxidative metabolism of rats. Rats were divided into three groups which received a control animal feed diet (A.F.), olive oil liquid diet (O.O) and corn oil liquid diet (C.O) for 30 days. It was observed that the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), increased in the liver and white fat tissue of rats fed with olive oil when compared to the corn oil group. However, in brown fat tissue and blood cells, the enzyme activities showed a tendency to decrease in the olive oil group. In addition, the effect of olive oil and corn oil on several glucose metabolism parameters (pyruvate, lactate, LDH, acetoacetate and beta-hydroxybutyrate) showed that corn oil impairs to a greater extent the cellular metabolism. All these results helped in concluding that some body tissues are more adversely affected than others by the administration of corn oil or olive oil, and their antioxidant defenses and cellular metabolism respond differently too.This work was supported by the Universidad Católica de Valencia “San Vicente Mártir” (grant number: UCV257-001)Nutrición humana y dietétic

Advances in interferometric techniques for the analysis of the three-dimensional flow in a lid-driven cylindrical cavity

Abstract: In this work, a qualitative and quantitative characterization of the three-dimensional flow in a lid-driven cylindrical cavity with different optical techniques is presented. Mach–Zehnder interferometry and photographic techniques have been used for a qualitative description of some flow features. However, the real challenge is to obtain quantitative measurements, as the cavity dimensions and geometry prevent the application of 3D digital techniques for measuring the flow velocity in the whole cavity with enough spatial resolution. Digital in-line holography was applied to the measure of the vortex-breakdown bubble that appears near the cavity bottom at Re = 2000. A 22 × 22 × 80 mm3 volume was recorded, its longest dimension parallel to the camera optical axis. This large volume in a liquid fluid combined with a high particle density forces us to develop new analysis strategies. Holograms have been analyzed using a new method, called Adaptive Cross Correlation with Tracking From Beginning, which includes the use of the reconstructed complex amplitude for particle localization. Particle tracking is based on the three-dimensional cross correlation of three-dimensional interrogation windows. The particle set defined in the first hologram is always used to find the particle position in subsequent holograms. This method provides an accurate 3D velocity map and the vortex-breakdown bubble spatial structure. Experimental and numerical data show a very good agreement. A new criterion for determining the accuracy in the particle position along the optical axis is introduced, achieving a spatial resolution of 0.1 mm. This tracking method can be applied not only to laminar flows but also to turbulent flows