2,749 research outputs found

    Les tests diagnostic dans la didactique des langues et des littératures

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    En este artículo se presenta una prueba diagnóstica elaborada para la medición de las habilidades lingüístico-comunicativas en los estudiantes de Secundaria. En la fundamentación teórica de dicha prueba diagnóstica ocupa una posición clave la conciencia metalingüística.In this paper presents a diagnostic test developed to measure language skills in Middle School students. On the theoretical basis of the diagnostic test metalinguistic, metalinguistic consciousness has a key role.Cet article présente un test diagnostic mis au point pour mesurer les habiletés de communication chez les élèves du collège. Dans les fondements théoriques de ce test diagnostic, la conscience métalinguistique joue un rôle clé

    Electro-optical Simulation of a-Si Thin-Film-Transistor Liquid Crystal Display Pixels

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    An analysis of an amorphous silicon (a-Si) thin-film-transistor liquid-crystal display (TFT-LCD) pixel is presented. The electro-optical model combines the electrical properties of the switching element and the optical performance of a twisted nematic (TN) liquid-crystal cell.Publicad

    Blue organic seven segment display based on poly (9,9-dioctyfluorene)with β-phase emission

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    In this work, organic seven segment displays based on poly(9,9-dioctyfluorene), PFO, have been fabricated. PFO has consolidated as an attractive material for PLEDs due to its efficient blue emission [1] and high hole mobility. Additionally, PFO has a particular conformation, called β-phase associated to extended PFO chain conformation, which is of great interest for potential device applications because, among all others, it has the highest photoluminescence quantum efficiency [2] and the best colour stability [3]. The structure fabricated uses Indium Tin Oxide (ITO) as anode, Poly(3,4 -ethylenedioxythiophene) /poly(4- styrenesulfonate) (PEDOT:PSS) as hole transport layer and Ba:Al as cathode. After thoroughly cleaning the substrates (covered with ITO) a photolithography process is carried out in order to pattern the anode. Next, the organic layers (PEDOTT:PSS and PFO) are spin casted. Finally, metals (Ba~30 nm and Al~100 nm) are thermally evaporated in an atmosphere of 6x10 -6 Torr. PFO is dissolved in toluene at 1 % wt. A detailed description of the fabrication process can be found in [4]. Finally, the device is encapsulated (using an epoxy and a glass tap) and contacts are indium soldered on the pads. In figure 1, we can observe the shadow mask used for the anode photolitography process (left) and the final device lighting in a zero configuration (right)

    Sustainable one-pot immobilization of enzymes in/on metal-organic framework materials

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    peer-reviewedThe industrial use of enzymes generally necessitates their immobilization onto solid supports. The well-known high affinity of enzymes for metal-organic framework (MOF) materials, together with the great versatility of MOFs in terms of structure, composition, functionalization and synthetic approaches, has led the scientific community to develop very different strategies for the immobilization of enzymes in/on MOFs. This review focuses on one of these strategies, namely, the one-pot enzyme immobilization within sustainable MOFs, which is particularly enticing as the resultant biocomposite Enzyme@MOFs have the potential to be: (i) prepared in situ, that is, in just one step; (ii) may be synthesized under sustainable conditions: with water as the sole solvent at room temperature with moderate pHs, etc.; (iii) are able to retain high enzyme loading; (iv) have negligible protein leaching; and (v) give enzymatic activities approaching that given by the corresponding free enzymes. Moreover, this methodology seems to be near-universal, as success has been achieved with different MOFs, with different enzymes and for different applications. So far, the metal ions forming the MOF materials have been chosen according to their low price, low toxicity and, of course, their possibility for generating MOFs at room temperature in water, in order to close the cycle of economic, environmental and energy sustainability in the synthesis, application and disposal life cycle

    Geomatic methods applied to the change study of the la Paúl Rock Glacier, Spanish Pyrenees

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    Producción CientíficaRock glaciers are one of the most important features of the mountain permafrost in the Pyrenees. La Paúl is an active rock glacier located in the north face of the Posets massif in the La Paúl glacier cirque (Spanish Pyrenees). This study presents the preliminary results of the La Paúl rock glacier monitoring works carried out through two geomatic technologies since 2013: Global Navigation Satellite System (GNSS) receivers and Terrestrial Laser Scanning (TLS) devices. Displacements measured on the rock glacier surface have demonstrated both the activity of the rock glacier and the utility of this equipment for the rock glaciers dynamic analysis. The glacier has exhibited the fastest displacements on its west side (over 35 cm yr-1), affected by the Little Ice Age, and frontal area (over 25 cm yr-1). As an indicator of permafrost in marginal environments and its peculiar morphology, La Paúl rock glacier encourages a more prolonged study and to the application of more geomatic techniques for its detailed analysis.Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (project CGL2015-68144-R)Junta de Extremadura - Fondo Europeo de Desarrollo Regional (project GR10071

    Coarse-grain molecular dynamics simulation framework to unravel the interactions of surfactants on silica surfaces for oil recovery

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    A coarse-grained molecular dynamics (CG-MD) framework, based on the MARTINI 3.0 model, was developed to characterise the interactions between surfactants and oil-silica substrates to resemble chemical enhanced oil recovery (EOR) processes. Previous computational studies, at the atomistic scale, addressed interactions between surfactants and oil over diverse surfaces. Even though simulations provided significant information involved throughout different stages of oil extraction from surfaces, atomistic scale simulations fail when approaching the time and size scale required to address the surfactant phase behaviour that can also impact the oil detachment. Our coarse-grained model aims to overcome the lack of computer approaches that can tackle the surfactant self-assembly and the formation of ordered structures in the removal of oil from silica substrates. A new MARTINI 3.0 coarse-grain framework to model silica surfaces and aqueous solutions of CiEj and C16TAB surfactants is presented. Coarse-grained simulations entailing a silica surface, covered by dodecane or eicosane were brought in contact with aqueous solutions of C16TAB and four nonionic CiEj (C8E6, C8E12, C12E6, C16E12) surfactants to resemble EOR processes with a size/time scale several orders of magnitude larger than previous simulations. The impact of concentration and hydrophilic-lipophilic balance (HLB) of surfactants on the detachment of dodecane and eicosane from the silica surface was evaluated by visual inspection of the simulation snapshots and the evolution of the solvent accessible surface areas (SASA). In contrast with previous atomistic simulations, nonionic surfactants seem the best candidates for an optimal oil removal from silica-based surfaces whereas the presence of charged moieties hinders the process. Diluted nonionic CE aqueous solutions were shown to be the most effective solutions, unlike more concentrated ones. When compared with dodecane, eicosane was less prone to be removed from the silica surface due to the increased alkyl chain length. Our study demonstrates that not only the surfactant nature but also the phase behaviour, clearly impact the detachment of oil from silica surfaces. This is an important aspect to consider for a proper choice of surfactants in EOR processes, that is only attainable through a coarse-grained framework.publishe

    The Role of Nrf2 Signaling in PPARβ/δ-Mediated Vascular Protection against Hyperglycemia-Induced Oxidative Stress

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    Hyperglycemia induces oxidative stress and plays a substantial role in the progression of vascular diseases. Here, we demonstrated the potentiality of peroxisome proliferator-activated receptor (PPAR)β/δ activation in attenuating high glucose-induced oxidative stress in endothelial cells and diabetic rats, pointing to the involvement of nuclear factor erythroid 2-related factor 2 (Nrf2). HUVECs exposed to high glucose showed increased levels of reactive oxygen species (ROS) and upregulated NOX-2, NOX-4, Nrf2, and NQO-1 effects that were significantly reversed by the PPARβ/δ agonists GW0742 and L165041. Both PPARβ/δ agonists, in a concentration-dependent manner, induced transcriptional and protein upregulation of heme oxygenase-1 (HO-1) under low- and high-glucose conditions. All effects of PPARβ/δ agonists were reversed by either pharmacological inhibition or siRNA-based downregulation of PPARβ/δ. These in vitro findings were confirmed in diabetic rats treated with GW0742. In conclusion, PPARβ/δ activation confers vascular protection against hyperglycemia-induced oxidative stress by suppressing NOX-2 and NOX-4 expression plus a direct induction of HO-1; with the subsequent downregulation of the Nrf2 pathway. Thus, PPARβ/δ activation could be of interest to prevent the progression of diabetic vascular complications.This work was supported by Grants from Ministerio de Economía y Competitividad and Fondo Europeo de Desar- rollo Regional (FEDER) (SAF2010-22066-C02-01, SAF2010-22066-C02-02, SAF2011-28150, SAF2014-55523- R), Junta de Andalucía (Proyecto de excelencia, P12-CTS- 2722), and Instituto de Salud Carlos III (RIC RD12/0042/ 0011), Spain

    Annual report on Sunspot Counting Program 2018

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    Este programa de observación nació a finales del año 2012 en la Universidad de Extremadura (Badajoz, 38°53′ N 6°58′ W) con el fin de ampliar aún más nuestra investigación en la reconstrucción de la actividad solar. Desde el 1 de Enero de 2013, nuestros recuentos de manchas solares se han presentado al Real Observatorio de Bélgica (ROB) como contribución a los esfuerzos internacionales de mantener y actualizar el número internacional de Manchas Solares. Para ello, hemos utilizado un pequeño refractor apocromático de 80 mm de diámetro de objetivo y 550 mm de longitud focal, a fin de proyectar una imagen de 150 mm de diámetro en una plantilla. Después se hace un dibujo para obtener el recuento de manchas solares. Además, se realizan observaciones solares desde una estación secundaria en Valencia de las Torres (38°24′ N 6°00′ W) con un refractor –70 mm de diámetro objetivo y 700 mm de distancia focal– cuando algunos días la estación principal (en Badajoz) falla. Este informe proporciona un conjunto completo de los datos obtenidos durante el año 2018, con cuatro tablas que muestran nuestros datos. Por otra parte, el índice de referencia de las manchas solares se compara con nuestros resultados. Esperamos que esta publicación sea de utilidad a la comunidad científica que estudia el número de manchas solares: la mayor serie de índices solares derivadas de la observación directa del Sol.This program was born in late 2012 at the University of Extremadura (Badajoz, 38°53′ N 6°58′ W) in order to further extend our research in the reconstruction of past solar activity (see, for example, Vaquero, 2007). Since 1st January 2013, our sunspot counts have been submitted to the Royal Observatory of Belgium (ROB) as a contribution to the international effort of maintaining and updating the International Sunspot Number. For this purpose, we use a small apochromatic refractor –80 mm of objective diameter and 550 mm of focal length– to project a 150 mm diameter image onto a template. Then, a drawing is done so we obtain our sunspot counts from it. Moreover, solar observations from a secondary station located in Valencia de las Torres (38°24′ N 6°00′ W) with a refractor –70 mm of objective diameter and 700 mm of focal length– are carried out some days when the main station (in Badajoz) fails. In this report, we provide a complete set of data obtained throughout the year 2018, with four tables including our data. Moreover, the reference sunspot index is compared with our results. We hope that this publication is useful to the scientific community studying the sunspot number: the longest solar index series derived from direct observation of the Sun.• Ministerio de Educación, Cultura y Deporte: Ayuda FPU / grant FPU. • Fondos FEDER-Junta de Extremadura: Ayuda al Grupo de Investigación GR18097 y Proyecto IB16127 / Research Group Grant GR18097 and project IB16127 • Ministerio de Economía y Competitividad of the Spanish Government proyecto CGL2017-87917-P / project CGL2017-87917-

    Annual report on Sunspot Counting Program 2013

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    Este programa nació a fines del 2012 en la Universidad de Extremadura con el fin de ampliar aún más nuestra investigación en la reconstrucción de la actividad solar. Desde el 1 de Enero de 2013, nuestro recuento de manchas solares se han presentado al Real Observatorio de Bélgica (ROB) como contribución a los esfuerzos internacionales de mantener y actualizar el número internacional de Manchas Solares. Para ello, hemos utilizado un pequeño refractor apocromático de 80 mm de diámetro de objetivo y 550 mm de longitud focal, a fin de proyectar una imagen de 150 mm de diámetro en una plantilla. Este informe proporciona un conjunto completo de los datos obtenidos durante el año 2013, con cuatro tablas que muestran nuestros datos. Por otra parte, el índice de referencia de las manchas solares se compara con nuestros resultados. Esperamos que esta publicación sea de utilidad a la comunidad científica que estudia el número de manchas solares: la mayor serie de índices solares derivadas de la observación directa del Sol.This program was born in late 2012 at the University of Extremadura in order to further extend our research in the reconstruction of past solar activity. Since 1st January 2013, our sunspot counts have been submitted to the Royal Observatory of Belgium (ROB) as a contribution to the international effort of maintaining and updating the International Sunspot Number. For this purpose, we have used a small apochromatic refractor –80mm of objective diameter and 550mm of focal length– to project a 150mm diameter image onto a template. In this report, we provide a complete set of data obtained throughout the year 2013, with four Tables showing our data. Moreover, the reference sunspot index is compared with our results. We hope that this publication be useful to the scientific community studying the sunspot number: the longest solar index series derived from direct observation of the Sun

    Cytotoxicity of three new triazolo-pyrimidine derivatives against the plant trypanosomatid: Phytomonas sp isolated from Euphorbia characias

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    There is no effective chemotherapy against diseases caused by Phytomonas sp., a plant trypanosomatid responsible for economic losses in major crops. We tested three triazolo-pyrimidine complexes [two with Pt(II), and another with Ru(III)] against promastigotes of Phytomonas sp. isolated from Euphorbia characias. The incorporation of radiolabelled precursors, ultrastructural alterations and changes in the pattern of metabolite excretion were examined. Different degrees of toxicity were found for each complex: the platinun compound showed an inhibition effect on nucleic acid synthesis, provoking alterations on the levels of mitochondria, nucleus and glycosomes. These results, together with others reported previously in our laboratory about the activity of pyrimidine derivatives, reflect the potential of these compounds as agents in the treatment of Phytomonas sp.Financial support Universidad de Granada (Spain), grant BIO 2000-1429
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