Experimental study for the determination of the turbulence onset in natural convection on inclined plates

In June, 8th, 2009 the balloon-borne solar telescope SUNRISE was launched from the Swedish Space Corporation balloon facility Esrange. A telescope with a mirror of 1 m in diameter ob-served the Sun during six days until the mission was terminated in Canada. The design process of SUNRISE and of any optical telescope requires the analysis of the effect of surrounding air on the quality of images. The turbulence encountered in the local telescope environment de-grades its optical performance. This phenomenon called `seeing' consists of optical aberrations produced by density non-homogeneities in the air along the optical path. The refraction index of air changes due to thermal non-uniformities so that the wavefront incident on the mirror is randomly distorted, and therefore, images are altered. When telescope mirrors are heated, as it happens in solar telescopes, and therefore they are at a temperature different from the environment's, natural convection occurs. It is then crucial to know whether the flow in front of the mirror is laminar or turbulent. After reviewing the literature, it was found that the scattering of results about the onset of the transition gives only rough orders of magnitude of the values of the critical Grashof numbers. Aiming to obtain more information about it, the problem of determination of the turbulence onset in natural convection on heated inclined plates in air environment was experimentally revisited. The transition has been determined from hot wire velocity measurements. The onset of turbulence has been considered to take place where velocity perturbations start to grow. Experiments have shown that the onset depends not only on the Grashof number, but also on other parameters as the temperature difference between the heated plate and the surrounding air. A correlation between dimensionless Grashof and Reynolds numbers has been obtained, fitting extraordinarily well the experimental data. The results are obtained in terms of non-dimensional numbers, this way they apply to any air pressure and therefore to any floating altitud

Pension funds: guarantors of international legality in Western Sahara? Evidence from Norway and Sweden

Natural resources have been defined by the Sahrawi Arab Democratic Republic, Polisario Front, and a number of non-governmental organisations not only as an essential part of the Western Sahara conflict, but also as a battlefield that has attracted the interest of the international community. This article explores how the ethical trade guidelines of two large institutional investors - the Norwegian and Swedish pension funds - have affected the behaviour of companies that export and exploit the natural resources of Western Sahara. The results of applying a triad-network model suggest that as pension funds have more instruments of influence, their strategy becomes more effective. Moreover, investments that follow ethical trade guidelines play a key role in pressuring companies to modify objectionable behaviours

Desarrollo de un modelo de Procesamiento del Lenguaje Natural para la extracción de información en documentos del dominio de la salud

En la actualidad existen múltiples modelos de inteligencia artificial centrados en la detección de entidades nombradas, que son capaces de detectar una amplia variedad de aspectos. En este trabajo, se centran esos aspectos a enfermedades raras, detectándolas en textos del ámbito clínico. Todos esos textos clínicos son resúmenes de documentos científicos publicados en PubMed. De las enfermedades, no solo se detectarán sus nombres en sí, sino que se quieren detectar una amplia variedad de aspectos relacionados con esas enfermedades, como por ejemplo, sus causas, tratamientos, diagnósticos... Todos esos aspectos se clasificarán en una serie de categorías. Las anotaciones del modelo se generarán, en primera instancia, de forma automática, usando la herramienta Metathesaurus, contenida dentro de UMLS, un sistema de lenguaje médico. Metathesaurus contiene más de 3 millones de conceptos, siendo la inmensa mayoría del ámbito clínico. Además, cuenta con una serie de categorías ya definidas, y con los conceptos clasificados en estas categorías. Para cada texto, se cuenta con un archivo txt que contiene el texto y un archivo ann que contiene sus anotaciones. Esas anotaciones se encuentran definidas en formato BRAT, un formato de anotación que permite después visualizarlas de forma fácil, modificarlas y crear nuevas. Para cada anotación, se especifica el inicio, final, la categoría a la que pertenece y las palabras o grupos de palabras sobre las que se aplica. Una vez se cuenta con esas anotaciones, es posible revisarlas manualmente para que el corpus sea de la mayor calidad posible, pero al tener una base ya de anotaciones, esta tarea será más ágil. La clasificación que se debe de realizar es compleja, ya que contiene bastantes categorías, además de que cada palabra (o grupos de palabras) pueden pertenecer a la vez a varias clases, por lo que las anotaciones se pueden superponer tanto de forma estricta (mismo inicio y final) como de forma parcial. Para la obtención del modelo, se contará como base PubMedBERT, un modelo basado en BERT reentrenado por Microsoft con vocabulario del ámbito clínico, también extraído de PubMed. Este modelo será ajustado para poder ser usado en esta tarea en concreto. Como es una tarea particular, se han definido una serie de métricas, diferenciando las tareas de detección y de clasificación. Esas métricas serán de utilidad para conocer el rendimiento del modelo, y poder ver así si es lo suficientemente bueno, o por contra, se deben de realizar mejoras para obtener mejor rendimiento. En conclusión, este trabajo busca desarrollar un modelo para la detección de enfermedades raras en textos clínicos, usando un corpus extraído de documentos científicos clínicos. Las anotaciones podrán solaparse, por lo que al tratarse de una tarea particular de detección de entidades, se realizan modificaciones sobre el modelo para reentrenarlo y métricas para medir el modelo resultante

Necesidades formativas en el grado de educación primaria de la facultad de ciencias de la educacion de la Universidad de Sevilla

El objetivo de la presente investigación ha sido analizar las necesidades formativas en el Grado de Educación Primaria de la Facultad de Ciencias de la Educación de la Universidad de Sevilla para extraer propuestas de mejora. La intención de la investigación es lograr que los futuros egresados salgan mejor preparados al mundo laboral. En el marco teórico se ha indagado sobre qué competencias necesitan los docentes en Educación Primaria, así como las exigencias educativas internacionales y nacionales. Se analiza cuál es la perspectiva de los profesionales de la educación sobre el grado. Así, se ha recabado la opinión de miembros clave de la comunidad educativa y universitaria a través de entrevistas, localizándose las necesidades formativas que debe cubrir el Grado en Educación Primaria. Se ha concluido que existen necesidades formativas en el grado. Los entrevistados coinciden en señalar que las prácticas curriculares son insuficientes, que se requieren mayores competencias digitales y prosociales, la falta de conocimiento práctico para gestionar la atención a la diversidad en las aulas, y una carencia a la hora de aprender a usar la legislación. Además, se establecen propuestas para futuras investigaciones: ampliar la muestra, aplicar una metodología mixta o contrastar con planes de estudio internacionales.The aim of this research was to analyse the training needs in the Primary Education Degree at the Faculty of Education Sciences of the University of Seville in order to extract proposals for improvement. The aim of the research is to ensure that future graduates are better prepared for the world of work. In the theoretical framework, we have investigated what competences primary school teachers need, as well as international and national educational requirements. The perspective of education professionals on the degree is analysed. Thus, the opinions of key members of the educational and university community were gathered through interviews. The training needs that the Bachelor's Degree in Primary Education should cover were identified. It has been concluded that there are training needs in the degree. The interviewees coincide in pointing out that curricular practices are insufficient, that greater digital and pro-social competences are required, the lack of practical knowledge to manage attention to diversity in the classroom, and a lack when it comes to learning to use legislation. In addition, proposals for future research are set out: expanding the sample, applying a mixed methodology or comparing with international curricula.Universidad de Sevilla. Grado de Pedagogí

On the onset of turbulence in natural convection on inclined plates

The problem of determination of the turbulence onset in natural convection on heated inclined plates in an air environment has been experimentally revisited. The transition has been detected by using hot wire velocity measurements. The onset of turbulence has been considered to take place where velocity fluctuations (measured through turbulence intensity) start to grow. Experiments have shown that the onset depends not only on the Grashof number defined in terms of the temperature difference between the heated plate and the surrounding air. A correlation between dimensionless Grashof and Reynolds numbers has been obtained, fitting quite well the experimental data

Galloping instabilities of Z-shaped shading louvers

Modern design of civil constructions such as office blocks, airport terminal buildings, factories, etc. incorporates more and more environmental considerations that lead to, amongst other elements, the use of glazed façades with shading devices to optimize energy consumption. These shading devices, normally slats or louvers, are very flexible structures exposed to the action of wind, and therefore aeroelastic effects such as galloping must be taken into account in their design. A typical cross-section for such elements is a Z-shaped profile made out of a central web and two side wings. The results of a parametric analysis based on static wind tunnel tests and performed on different Z-shaped louvers to determine translational galloping instability regions are presented in this paper

Experimental determination of the onset of turbulence on inclined plates using hot wire velocity measurements

The problem of determination of the turbulence onset in natural convection on heated inclined plates in an air environment has been experimentally revisited. The transition has been detected by using hot wire velocity measurements. The onset of turbulence has been considered to take place where velocity fluctuations (measured through turbulence intensity) start to grow. Experiments have shown that the distance to the plate edge where the onset begins depends both on the plate inclination angle and the plate temperature, and thus on the Grashof number defined in terms of the temperature difference between the heated plate and the surrounding air. An experimental setup to measure the above mentioned distance has been developed. In this paper, such an apparatus is presented, as well as the experimental procedure and some experimental results

Social and political approach of female genital mutilation

La mutilación genital femenina (MGF) ha entrado en la agenda social y política de los diferentes organismos internacionales hace ya algunas décadas, siendo ya numerosas las acciones que se han desarrollado en países donde esta práctica es habitual. Posteriormente, en países receptores de inmigración, también se han puesto en marcha medidas legislativas específicas que la prohíben y la penalizan. En este sentido hay que destacar que aunque estas medidas legislativas están bastante extendidas, además son necesarias otras iniciativas políticas y sociales relacionadas con un mayor conocimiento y sensibilización de la MGF y que, desde un abordaje comunitario, cuente con la implicación de las personas que ejercen el liderazgo en la comunidad. La participación de la administración, junto con otros actores sociales, debe asegurarse con el desarrollo de protocolos donde todas aquellas entidades públicas y privadas que trabajen con población inmigrante en los ámbitos de la justicia, policía, salud, educación y trabajo social tengan representación. Con este trabajo se pretende hacer un análisis de las medidas sociales y políticas se han puesto en marcha a nivel nacional e internacional para lograr la erradicación de la MGF. En este sentido, el análisis se centra en Mali, al tratarse de un país africano que presenta una alta prevalencia de MGF.Female genital mutilation (FGM) went into the social and political agenda of different international organisms some decades ago, with several actions that have been developed in countries where this practice is common. Later, specific legislative measures have been set up in immigration recipient countries to forbid and penalize it.Although these legislative measures are quite widespread, other political and social initiatives are necessary as well that entail a deeper knowledge and higher awareness of FGM and involve communities and their leaders. The participation of public administrations andother social actors must be ensured with the development of plans of action where public and private entities work with immigrant population in the fields of law, health, education and social work. In this paper, we analyze those social and political measures set up at the national and international levels to reach FGM eradication

Enhanced photostability and sensing performance of graphene quantum dots encapsulated in electrospun polyacrylonitrile nanofibrous filtering membranes

We report a method to encapsulate graphene quantum dots (GQD) in polyacrylonitrile (PAN) nanofibrous membranes to manufacture robust filtering membranes by electrospinning. GQD-PAN membranes with different nanofiber diameter were prepared tuning the electrospinning parameters, all exhibiting the characteristic fluorescence fingerprint of the GQD probes. The photoluminescence (PL) stability of GQD embedded in the PAN fibers was significantly enhanced with respect to that of water dispersed GQD luminescent probes. The PL of GQD-PAN filtering membranes showed remarkable time stability, both stored dry and immersed in phosphate buffer solutions (PBS), as well as exposed to continuous light irradiation. However, the PL intensity of GQD-PAN membranes was irreversibly quenched by highly oxidant free chlorine solutions. Thus, electrospun GQD-PAN membranes exhibited excellent performance as turn-off fluorescence sensing platforms for free chlorine detection in PBS 0.1 M pH 7. The analytical performance of GQD-PAN membranes was comparable to that of GQD solutions with optimal concentrations, displaying a fast (no need of incubation time) and linear response to chlorine concentration in the 10–600 μM range, a low detection limit of 2 μM, high sensitivity, reproducibility and selectivity. Moreover, the sensing performance of the membranes was very stable after being immersed in PBS for months, outperforming the stability of GQD solutions

Algunas consideraciones de carácter docente sobre la circulación en los perfiles aerodinámicos y la posición del punto de remanso anterior.

Algunas consideraciones de carácter docente sobre la circulación en los perfiles aerodinámicos y la posición del punto de remanso anterior