867 research outputs found

    Equity in the mobility of students in the Erasmus program: Case study of the University of Málaga

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    The aim of this paper is to know which are the factors related to equity that condition students for the application, or not, for a scholarship within the ERASMUS program. The main study is carried out in 6 Spanish Universities, among which is the University of Malaga, which has the highest number of data collected. The participants sample consists of non-applicant and applicant students for a scholarship within the ERASMUS program. The latter are divided among those who have not begun their stay yet; those who have already begun it; and, students who have completed their stay in foreign country. All of them have been given an online questionnaire designed in its entirety for the project. The results obtained shows that in a large part of the items related to concerns about the stay abroad are related to the economic possibilities of the students to cover the expenses in the country of destinationEl objetivo de este trabajo es conocer cuáles son los factores relacionados con la equidad que condicionan a los estudiantes para la solicitud, o no, de una beca dentro del programa ERASMUS. El estudio principal se desarrolla en 6 Universidades Españolas, entre las que se encuentra la Universidad de Málaga, la cual cuenta con mayor número de datos recogidos. La muestra participante se compone de estudiantes no solicitantes y solicitantes de una beca dentro del programa ERASMUS. Éstos últimos están divididos entre quienes aún no han empezado su estancia; aquellos que ya la han comenzado; y los estudiantes que ya han finalizado la estancia. A todos ellos se les ha pasado un cuestionario online diseñado en su totalidad para el proyecto. Los resultados obtenidos muestran que en gran parte de los ítems referidos a preocupaciones sobre la estancia en el extranjero están relacionadas con las posibilidades económicas de los estudiantes para cubrir los gastos en el país de destinoEl presente trabajo se encuadra en el marco del proyecto I+D+I “Equidad y Movilidad Universitaria en el nuevo marco del Espacio Europeo de Educación Superior: Análisis del Índice de Elegibilidad ERASMUS a la luz de factores socioeconómicos (Ref.:EDU 2012-36739) dirigido por Javier M. Valle en el seno del Grupo de Investigación sobre Políticas Educativas Supranacionales (GIPES) de la Universidad Autónoma de Madri

    Proposing to use artificial neural Networks for NoSQL attack detection

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    [EN] Relationships databases have enjoyed a certain boom in software worlds until now. These days, with the rise of modern applications, unstructured data production, traditional databases do not completely meet the needs of all systems. Regarding these issues, NOSQL databases have been developed and are a good alternative. But security aspects stay behind. Injection attacks are the most serious class of web attacks that are not taken seriously in NoSQL. This paper presents a Neural Network model approach for NoSQL injection. This method attempts to use the best and most effective features to identify an injection. The features used are divided into two categories, the first one based on the content of the request, and the second one independent of the request meta parameters. In order to detect attack payloads features, we work on character level analysis to obtain malicious rate of user inputs. The results demonstrate that our model has detected more attack payloads compare with models that work black list approach in keyword level

    Lignin transformation by a versatile peroxidase from a novel bjerkandera sp. strain

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    A versatile peroxidase, purified from a novel strain of Bjerkandera sp. (B33/3), was tested for its reactivity on a lignin fraction obtained from straw pulping. The effects of such processing parameters as reaction time, pH, and lignin:enzyme ratio were evaluated. Gel filtration chromatography was employed to characterise the molecular mass distribution of the lignin fragments produced by the enzyme-mediated reaction. Our results have shown that such a versatile peroxidase can directly bring about transformations of lignin, even in the absence of external mediators

    Purification, kinetics and spectral characterisation of a new versatile peroxidase from a Bjerkandera Sp. isolate

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    From the extracellular fluid of a novel strain of Bjerkandera sp., it was isolated, purified and identified the main enzyme responsible for Remazol Brilliant Blue R dye decolourisation. Such an enzyme is able to oxidise manganese, as well as veratryl alcohol and 2,6-dimethoxyphenol in manganese-independent reactions; hence, it can be included in the new group of versatile peroxidases. The molecular mass of said enzyme is ca. 45 kDa, and the N-terminal amino acid sequence obtained by Edman degradation is VAXPDGVNTA. The enzyme substrate range for oxidation of several phenolic and non-phenolic aromatic compounds was determined and the corresponding Michaelis-Menten kinetic constants calculated. Furthermore, spectrophotometric assays showing the Soret band and allowing observation of band shifts of the enzyme led to the conclusion that Bjerkandera strains may also synthesise at least two different versatile peroxidases, as happens with Pleurotus eryngii

    Component integration strategies in metamorphic 4-junction III-V concentrator solar cells

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    Progressing beyond 3-junction inverted-metamorphic multijunction solar cells grown on GaAs substrates, to 4-junction devices, requires the development of high quality metamorphic 0.7 eV GaInAs solar cells. Once accomplished, the integration of this subcell into a full, Monolithic, series connected, 4J-IMM structure demands the development of a metamorphic tunnel junction lattice matched to the 1eV GaInAs subcell. Moreover, the 0.7 eV junction adds about 2 hours of growth time to the structure, implying a heavier annealing of the subcells and tunnel junctions grown first. The final 4J structure is above 20 Pm thick, with about half of this thickness used by the metamorphic buffers required to change the lattice constant throughout the structure. Thinning of these buffers would help reduce the total thickness of the 4J structure to decrease its growth cost and the annealing time. These three topics: development of a metamorphic tunnel junction for the 4th junction, analysis of the annealing, and thinning of the structure, are tackled in this work. The results presented show the successful implementation of an antimonide-based tunnel junction for the 4th junction and of pathways to mitigate the impact of annealing and reduce the thickness of the metamorphic buffers

    Experimental and modeling analysis of internal luminescence in III-V solar cells

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    In high quality solar cells, the internal luminescence can be harnessed to enhance the overall performance. Internal confinement of the photons can lead to an increased open-circuit voltage and short-circuit current. Alternatively, in multijunction solar cells the photons can be coupled from a higher bandgap junction to a lower bandgap junction for enhanced performance. We model the solar cell as an optical cavity and compare calculated performance characteristics with measurements. We also describe how very high luminescent coupling alleviates the need for top-cell thinning to achieve current-matching

    Biovalorization of technical lignins for added-value products and applications

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    Lignin is an abundant non-toxic amorphous natural polymer. Nowadays it is available a great variety and large amounts of technical lignins as by-products from the pulp and paper industries. Some successful biotechnological applications of enzymatically modified lignins are described in the literature, namely for the production of lignin based copolymers, binders for wood composites, chelating agents, compositions for treating porous materials, coatings, paintings and others. From a new species from Bjerkandera genus which exhibits high decolourisation activity on Poly R-478 and Remazol Brilliant Blue R (RBBR) dyes, was isolated, purified and identified the main enzyme responsible for Remazol Brilliant Blue R dye decolourisation. Such an enzyme is able to oxidise manganese, as well as VA and DMP in manganese-independent reactions; the enzyme substrate range for oxidation of several phenolic and non-phenolic aromatic compounds was determined. This enzyme was tested for transformation of a lignin fraction obtained from straw pulping. Characterisation by gel filtration chromatography of the evolution of the molecular mass distribution of the lignin fragments generated by said enzyme indicated that this enzyme is able to interact directly with lignin in the absence of other mediators

    TRACE ELEMENTS IN SHEEP AND GOATS REPRODUCTION: A REVIEW

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    The reproduction of small ruminants like goats and sheep managed under extensive range grazing conditions can be affected by nutrients availability and especially by the mineral content of the forages resources on the rangeland. It has been particularly demonstrated that trace elements can have equally, beneficial or detrimental effects, depending on its balance, on reproductive functions in small ruminants. Trace elements as copper, molybdenum, selenium and zinc play key role on the metabolism of carbohydrates, proteins and lipids; however, the mode of action by which these elements affect reproduction in sheep and goats are not completely understood, due to the complexity in the mode of action of the metallobiomolecules and the neuro-hormonal relationship. In this way, their absence or presence of these minerals in several organs, fluids, or tissues of the reproductive tract have allowed obtaining information on the metabolism and the role of these elements on reproduction in sheep and goats. On this regard, the objective of this document is to review the relationships and effects of some trace elements, on reproductive events in sheep and goats

    Metamorphic III-V solar cells: recent progress and potential

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    Metamorphic semiconductor devices are commonly considered to have inferior electronic quality. However, recent development of compositionally graded buffers and junction structures have led to the achievement of high quality metamorphic solar cells exhibiting internal luminescence efficiencies over 90%. Optimizing the optical design of the solar cell becomes important in order to enhance photon recycling and open circuit voltage in these cells. In this paper we first present recent performance results for 1eV and 0.7eV GaInAs solar cells grown on GaAs substrates. Then an electro-optical model is used to assess the potential performance improvements in current metamorphic solar cells under different realizable design scenarios. The results show that significant improvements can be achieved by improving both the electronic quality and optics of these cells
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