762 research outputs found
La distribución intraurbana de los inmigrantes en las ciudades españolas: un análisis de casos con SIG y técnicas cuantitativas
En las ciudades españolas cada vez es más habitual la existencia de áreas y espacios diferenciados por cuestiones sociales, económicas o étnicas. La vulnerabilidad a esta situación de determinados colectivos y la segregación residencial a la que se ven abocados algunos de ellos, especialmente los inmigrantes extranjeros, constituirán el objeto de estudio de esta investigación.
Este artículo presenta, además, un doble objetivo. Por un lado, la realización de un análisis socioespacial mediante SIG. El análisis se apoyará en la aplicación de una serie de índices estadísticos de segregación residencial en los inmigrantes extranjeros de determinadas nacionalidades. Por otro lado, se examinarán sus patrones de localización a escala intraurbana en tres de las mayores ciudades españolas, Madrid, Barcelona y Sevilla. El análisis de estas ciudades será abordado desde una metodología comparativa y desde una perspectiva multi-escalar, que servirán para poner de manifiesto y valorar el patrón de distribución espacial del grupo mencionado
A first experimental evidence by transmission electron microscopy of dislocation disociation in the TeO2 system
En este trabajo se pretende analizar la microestructura de monocristales de TeO2 (paratelurita) deformados plásticamente en compresión uniaxial a alta temperatura (∼870 K) en distintas condiciones. Para ello, se han ensayado muestras con orientación cristalográfica [110], y se han cortado láminas correspondientes a los planos de deslizamiento para ser observadas con microscopía electrónica de transmisión. El estudio de la subestructura de dislocaciones en este material es complejo debido a su alta anisotropía. La observación de dicha microestructura ha puesto de manifiesto la presencia de disociación de dislocaciones. Es la primera vez que se encuentra este fenómeno en la paratelurita. De la distancia de equilibrio entre dislocaciones parciales, se ha podido obtener una estimación de la energía de falta de apilamiento en este sistema.This work intends to analyse the microstructure of paratellurite (TeO2 single crystals) plastically deformed at high temperature ∼870 K) in uniaxial compression along [110]. Samples have been mechanically tested, and thin foils have been cut from them, corresponding to the slip systems to be observed in transmission electron microscopy. The study of the dislocation substructure in this material is rather complex due to its high anisotropy. Microstructural observation by TEM has put into evidence the presence of dislocation dissociation. This is the first work reporting this fact. From the equilibrium distance between partials, an estimation of the stacking fault energy has been carried out
Low X-ray Luminosity Galaxy Clusters. III: Weak Lensing Mass Determination at 0.18 z 0.70
This is the third of a series of papers of low X-ray luminosity galaxy
clusters. In this work we present the weak lensing analysis of eight clusters,
based on observations obtained with the Gemini Multi-Object Spectrograph in the
, and passbands. For this purpose, we have developed a pipeline
for the lensing analysis of ground-based images and we have performed tests
applied to simulated data. We have determined the masses of seven galaxy
clusters, six of them measured for the first time. For the four clusters with
availably spectroscopic data, we find a general agreement between the velocity
dispersions obtained via weak lensing assuming a Singular Isothermal Sphere
profile, and those obtained from the redshift distribution of member galaxies.
The correlation between our weak lensing mass determinations and the X-ray
luminosities are suitably fitted by other observations of the
relation and models
Signos neuromusculares anormales tras la anestesia con romifidina-propofol-halotano en dos algas
Dos galgas (ASA I, con edades de 1.5 y 8 años) incluídas en un estudio anestésico experimental, mostraron signos de una reacción neuromuscular epileptiforme con mioclonías, movimientos natatorios de las extremidades anteriores y opistótonos, durante el inicio de la recuperación anestésica en varios procedimientos anestésicos. Ninguna tenía antecedentes de epilepsia. Las dos fueron anestesiadas con los siguientes protocolos anestésicos: 1. Romifidina (ROM) Ilvl-Atropina (ATR)- Propofol (PRO)-Halotano (HAL), 2. ROM IV-ATRPRO-HAL. 3. Xilacina (XIL)-ATR-PRO-HAL, 4. Medetomidina (MED)-ATR-PRO-HAL y 5. ROMATR-Tiopental sódico (TIO)-HAL. Las perras no fueron sometidas a ninguna intervención quirúrgica. La anestesia se mantuvo durante 60 minutos en todos los casos. Las variables anestésicas y los parámetros sanguíneos estudiados se mantuvieron dentro de los rangos normales. La galga mayor mostró el cuadro descrito en los protocolos 1, 2 y 3 (más marcado en el 2), mientras que la más joven sólo los presentó en el 2, y con una menor intensidad en los signos clínicos. En todos los casos, éstos aparecieron de 2 a 5 minutos después de terminar la administración de halotano, y tras 15 minutos, y adoptar las pacientes el decúbito esternal, los signos cesaron. No fue necesario administrar ningún fármaco para aliviar el cuadro convulsivo. A partir de entonces, la recuperación fue normal y las pacientes no mostraron posteriormente síntomas nerviosos.Two female Greyhounds (ASA I, aged 1.5 and 8 years) showed signs of a neuromuscular epileptiforrn activity, with paddling, opisthotonus and shivering, during the anaesthetic recovery in some anaesthetic protocols. No epilepsy history was registered befare in any patient. The dogs were anaesthetized with the following procedures: 1. Romifidine (ROM) IMAtropine (ATR)-Propofol (PRO)-Halothane (HAL), 2. ROM IV-ATR-PRO-HAL. 3. Xylazine (XIL)-ATR-PROHAL, 4. Medetomidine (MED)-ATR-PRO-HAL y 5. ROM-ATR-Thiopentone (TIO)-HAL. The older Greyhound showed an epileptiforrn activity in the protocols 1, 2 and 3 (more intense in 2), however the younger one only exhibited these signs in the protocol 2. The older one suffered excitatory phenomena deeper than the other one. In all cases, signs began 2-5 minutes after the end of the halothane administration, and after 15 minutes, when the patients adopted the sternal recumbency the signs disappeared. Anaesthetic variables and haematological values were within normal limits. No drug was administered for treating the excitatory phenomena. The recovery was normal and the dogs did not exhibite nervous signs later
Performance Evaluation of Sparse Matrix Products in UPC
This is a post-peer-review, pre-copyedit version of an article published in The Journal of Supercomputing. The final authenticated version is available online at: https://doi.org/10.1007/s11227-012-0796-4[Abstract] Unified Parallel C (UPC) is a Partitioned Global Address Space (PGAS) language whose popularity has increased during the last years owing to its high programmability and reasonable performance through an efficient exploitation of data locality, especially on hierarchical architectures like multicore clusters. However, the performance issues that arise in this language due to the irregular structure of sparse matrix operations have not yet been studied. Among them, the selection of an adequate storage format for the sparse matrices can significantly improve the efficiency of the parallel codes. This paper presents an evaluation, using UPC, of the most common sparse storage formats with different implementations of the matrix-vector and matrix-matrix products, which are key kernels in many scientific applications.Ministerio de Ciencia e Innovación; TIN2010-16735Ministerio de Educación; AP2008-01578Ministerio de Ciencia e Innovación; CAPAP-H3; TIN2010-12011-
Study of Fucoidans as Natural Biomolecules for Therapeutical Applications in Osteoarthritis
[Abstract]
Osteoarthritis (OA) is the most prevalent articular chronic disease. Although, to date there is no cure for OA. Fucoidans, one of the main therapeutic components of brown algae, have emerged as promising molecules in OA treatment. However, the variability between fucoidans makes difficult the pursuit of the most suitable candidate to target specific pathological processes. By an in vitro experimental approach in chondrocytes and fibroblast-like synoviocytes, we observed that chemical composition of fucoidan, and specifically the phlorotannin content and the ratio sulfate:fucose, seems critically relevant for its biological activity. Nonetheless, other factors like concentration and molecular weight of the fucoidan may influence on its beneficial effects. Additionally, a cell-type dependent response was also detected. Thus, our results shed light on the potential use of fucoidans as natural molecules in the treatment of key pathological processes in the joint that favor the development of rheumatic disorders as OA.Xunta de Galicia; ED431G2019/0
Preparación, caracterización y estudio morfológico de fibras de carbón activado
Utilizando fibras de kenaf larga, se ha llevado a cabo la preparación, caracterización y estudio morfológico de las fibras de carbón activado (ACFs). La caracterización era realizada mediante las isotermas de adsorción de N2 a -196 C, porosimetría de Hg y microscopia electrónica de barrido. La activación a 700 ºC con CO2 durante 2h (FBC4A72) y 4 h (FBC4A74) de la muestra carbonizada a 400 ºC durante 0.5 h en N2 (FBC4), mostraban un incremento en el tamaño del poro, como se observa en las microscopías electrónica de barrido. Esto es probablemente debido a la interconexión de los poros como consecuencia del incremento del tiempo de tratamiento de 2 a 4h. Estos resultados abren un amplio campo de aplicación para las fibras de kenaf.Using kenaf as starting material, a study about the preparation and characterization of activated carbon fibers (ACFs) from long fibers was carried out. The carbonization products of kenaf fibers and ACFs
were texturally characterized by N2 adsorption at -196 ºC, mercury porosimetry, and scanning electron microscopy. The activation of the raw material of Kenaf by its carbonization at 400 ºC for 0.5 h in a N2 atmosphere increase the porosity of the samples, particularly the activation at 700 ºC with carbon dioxide. It should be noted the porous development shown by the scanning electron micrographs of samples FBC4A72 and FBC4A74. It is observed that the variation of treatment time from 2 to 4 hours leads to an important
development of the porous structure in samples FBC4A74, which is probably a consequence of an interconnection between pores. These results open a wide field of applications of these fibers.peerReviewe
Using Process Mining to Analyze Time-Distribution of Self-Assessment and Formative Assessment Exercises on an Online Learning Tool
The study of the relationships between self-regulated learning and formative assessment is an active line of research in the educational community. A recent review of the literature highlights that the study of these connections has been mainly unidirectional, focusing on how formative assessment helps students to self-regulate their learning, being much less explored the effect of self-regulated learning strategies on formative assessment. In this context, analyzing automatically captured students’ activities within online learning tools can provide us further insights on the interactions between these two topics. More specifically, this article examines the activity traces of 382 students who used an online tool to learn a programming language. The tool incorporates review exercises for promoting self-assessment (an important self-regulated learning strategy). Furthermore, the tool is used in supervised laboratories where students receive formative assessment. This study uses process mining techniques to analyze the temporal component of student behavior in both types of activities, their interaction, and how self-assessment relates to formative assessment. Some key lessons are learned: activities promoting self-assessment significantly improved students’ involvement in formative assessment activities; increasing selfassessment cannot compensate for a lack of effort in formative assessment. We also underline that, to the best of our knowledge, to date no research has used process mining to consider the time component in the analysis of the relationships between formative assessment and self-assessment
Argumentación y metáfora en el discurso político en torno a la inmigración
The conceptual metaphor, developed within the framework of cognitive linguistics, constitutes a tool for both supporting and refuting trains of argument; it therefore enables a collection of polyphonic voices to be identified, reflecting opposing ideologies and representing their particular vision of the events under debate. From a corpus of texts belonging to the “hypergenre” of the social debate concerning immigration, we analyse the conceptual and linguistic metaphors that categorize the host country and the image of immigrants. Through a study of this imagery, we demonstrate that the choice of source domains and of conceptual structures generates a virtual dialogue between opposing ideologies—supporters and detractors of the phenomenon of immigration— and show that, in effect, metaphor plays an important role in the process of argument.La metáfora conceptual, desarrollada en el marco de la lingu..stica cognitiva, constituye una herramienta más al servicio de las operaciones de apoyo y refutación propias de la secuencia argumentativa y, por ello, permite reconocer un juego de voces polifónicas a través del cual se reflejan ideologías opuestas que representan su particular visión sobre los acontecimientos debatidos. A partir de un corpus de textos pertenecientes al hipergénero del debate social en torno a la inmigración, se analizan las metáforas conceptuales y lingüisticas que categorizan el país receptor de inmigrantes y la imagen que de estos se tiene. Mediante el estudio de esta imaginería se comprueba cómo la selección de los dominios fuente y de las estructuras conceptuales que generan propician el diálogo virtual entre ideologías opuestas, defensora y detractora del fenómeno de la inmigración, y se pone de manifiesto que, efectivamente, la metáfora desempeña una función relevante en la argumentació
Traducción y censura en la España franquista
En partant de l’hypothèse selon laquelle le traducteur, fort de son bagage cognitif, interprète le texte qu’il traduit et que la traduction est un phénomène de réécriture, cet article analyse la version espagnole de l’œuvre de la romancière française Sidonie Gabrielle Colette, Claudine à Paris, traduite par Piñas en 1963. L’objectif de cette analyse est de démontrer comment une circonstance historique concrète, la censure imposée par la dictature franquiste, influe sur la traduction.Assuming that the translator, cleverer from his stock of cognitive knowledge, interprets the text he translates, and that translation is a phenomenon of rewriting, this article examines the Spanish version of «Claudine à Paris» by the French novelist Sidonie Gabrielle Colette, translated by Piñas in 1963. The analysis aims at demonstrating how concrete historical circumstances –the censorship imposed by Franco’s dictatorship– influences the work.Partiendo de la premisa de que el traductor interpreta el texto que traduce aportando a esta interpretación su bagaje cognitivo y de que, por tanto, la traducción es un fenómeno de reescritura, este trabajo analiza la versión española de la novela Claudine à Paris, de la escritora francesa Sidonie Gabrielle Colette, traducida por Piñas en 1963, con el fin de demostrar cómo una circunstancia histórica concreta, la censura impuesta por la dictadura franquista, incide sobre el trabajo de traducción
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