1,962 research outputs found

    Scattering of Elastic Waves in a Quasi-one-dimensional Cavity: Theory and Experiment

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    We study the scattering of torsional waves through a quasi-one-dimensional cavity both, from the experimental and theoretical points of view. The experiment consists of an elastic rod with square cross section. In order to form a cavity, a notch at a certain distance of one end of the rod was grooved. To absorb the waves, at the other side of the rod, a wedge, covered by an absorbing foam, was machined. In the theoretical description, the scattering matrix S of the torsional waves was obtained. The distribution of S is given by Poisson's kernel. The theoretical predictions show an excellent agreement with the experimental results. This experiment corresponds, in quantum mechanics, to the scattering by a delta potential, in one dimension, located at a certain distance from an impenetrable wall

    Electromagnetic prompt response in an elastic wave cavity

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    A rapid, or prompt response, of an electromagnetic nature, is found in an elastic wave scattering experiment. The experiment is performed with torsional elastic waves in a quasi-one-dimensional cavity with one port, formed by a notch grooved at a certain distance from the free end of a beam. The stationary patterns are diminished using a passive vibration isolation system at the other end of the beam. The measurement of the resonances is performed with non-contact electromagnetic-acoustic transducers outside the cavity. In the Argand plane, each resonance describes a circle over a base impedance curve which comes from the electromagnetic components of the equipment. A model, based on a variation of Poisson's kernel is developed. Excellent agreement between theory and experiment is obtained.Comment: 4 pages, 5 figure

    Innovate to Educate: Use of mobile devices in the teaching and learning of English

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    La utilización de los dispositivos móviles para la enseñanza y aprendizaje de la lengua inglesa implica una exploración profunda de nuestra práctica y diseño docente. El presente estudio desvela a través del paradigma de las ciencias cognitivas algunos conceptos base que han sustentado la educación española, sugiere el empleo de los dispositivos como herramientas de innovación y por último analiza diversos materiales disponibles en la red para su aplicación en entornos educativos.The use of mobile devices to teach and learn English involves a deep exploration of our practice and teaching design. This paper reveals through the paradigm of cognitive science core concepts that have sustained the Spanish education, it suggests the use of the mobile devices as tools to develop innovation and finally it examines various materials available online to apply in educational environments

    The development of a protocol for the analysis of genetic expression through «differential display», as a means to reducing the number of false positives

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    Entre los métodos empleados para los análisis de la expresión de genes, el método de "differentialdisplay" ha sido ampliamente utilizado y, a pesar del uso extendido de los "microarrays", es aún unmétodo válido para el análisis con muestras cuyo transcriptoma es desconocido. Con el objeto de reducirel elevado número de falsos positivos que genera esta técnica, hemos optimizado el protocolo parareducir la posibilidad de generar falsos positivos. En primer lugar, hemos marcado radiactivamente elcebador oligo-dT con lo que los fragmentos de DNA identificados son extremos 3'-UTR de RNAm. Pormuestra hemos realizado dos transcripciones inversas y dos reacciones de PCR en cada una de ellas. Paraseleccionar un fragmento de DNA, debía estar diferencialmente expresado en las 4 reacciones de PCR.Por último, todos los fragmentos fueron clonados y secuenciados por triplicado. Estas modificacionesal protocolo nos ha permitido identificar 5 genes expresados diferencialmente entre células epitelialesde intestino en estado proliferativo y diferenciado.The analysis of genetic expression, the differential display (DD) method has been widely used, but inspite of the extensive use of the «microarrays» method, it is still to be considered as a valid methodfor the analysis of samples whose transcriptone is not known. In this work, an attempt has been madeto reduce the high number of false positives generated by this technique by optimising method protocol.As a preliminary step, we radioactively marked the oligo dT primer with which the fragments ofidentified DNA were extreme 3'-UTR of mRNA. For each sample two inverse transcriptions and twoPCR reactions were performed. Only fragments of DNA that are expressed differentially in all 4 PCRreactions should be selected. Finally, all of the fragments were cloned and sequenced in triplicate. Theseprotocol modifications have allowed us to identify 5 differentially expressed genes, in intestinal epithelialcells in both proliferative and differentiated states

    Synthesis of New Analogues of the Bengamides: Peptidyl Bengamides and Molecular Probes

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    Isolated from sponges of the Jaspidae family, first members where discovered in 1986. The bengamides represent an interesting and unprecedented family of natural products that displayed striking antitumor activities [1]. The recognition of these natural products as antiangiogenic compounds, in virtue to their inhibition of methionine aminopeptidases, prompted intense research activities in the chemical and biological fields. In fact, the total synthesis of the natural products, together with an extensive variety of analogues, has been reported in the literature [2]. Particularly, we have recently developed a new synthetic methodology which allowed rapid and efficient access to the natural bengamide E (1), together with a wide library of analogues of which the cyclopentyl analogue 2 was identified as a more potent antitumor compound with respect to its natural congener [3]. As continuation of these synthetic efforts, with the objective of identifying new potent and promising analogues, we wish to report our recent synthetic studies directed to the synthesis of new bengamide analogues, featured by the replacement of the caprolactam fragment by a peptidyl residue (compounds type 3). On the other hand, in order to gain insight into the mechanism of the biological action of the bengamides, we describe the preparation of the N-alkyl derivatives 4 and 5, which represent interesting molecules that could be employed as suitable molecular probes.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    A methodological proposal and tool support for the HL7 standards compliance in the development of health information systems

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    Health information systems are increasingly complex, and their development is presented as a challenge for software development companies offering quality, maintainable and interoperable products. HL7 (Health level 7) International, an international non-profit organization, defines and maintains standards related to health information systems. However, the modelling languages proposed by HL7 are far removed from standard languages and widely known by software engineers. In these lines, NDT is a software development methodology that has a support tool called NDT-Suite and is based, on the one hand, on the paradigm of model-driven engineering and, on the other hand, in UML that is a widely recognized standard language. This paper proposes an extension of the NDT methodology called MoDHE (Model Driven Health Engineering) to offer software engineers a methodology capable of modelling health information systems conforming to HL7 using UML domain models

    Las bibliotecas universitarias en un entorno de enseñanza virtual

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    The academic libraries, in the beginnings of the XXIst century, are faced to a new model of education, where the virtual environment is fundamental. The above mentioned libraries, in his functions like CRAI, will be seen in the challenge of adapting his collections and services to the education platforms, of supporting to the professorship in the making of multimedia products and of designing a politics of literacy of information. The literacy informacional has turned into a fundamental axis in the new model of education defined by the European Space of Higher education, therefore an important part of our efforts must go towards his integration in the new educational proposal

    Las bibliotecas universitarias en un entorno de enseñanza virtual

    Get PDF
    The academic libraries, in the beginnings of the XXIst century, are faced to a new model of education, where the virtual environment is fundamental. The above mentioned libraries, in his functions like CRAI, will be seen in the challenge of adapting his collections and services to the education platforms, of supporting to the professorship in the making of multimedia products and of designing a politics of literacy of information. The literacy informacional has turned into a fundamental axis in the new model of education defined by the European Space of Higher education, therefore an important part of our efforts must go towards his integration in the new educational proposal

    Diseño de materiales multimedia para la formación de competencias informacionales

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    Los tutoriales multimedia se han convertido en objetos de aprendizaje esenciales en las políticas de formación en competencias informacionales, así como en el aprendizaje autónomo que se potencia en el Espacio Europeo de Enseñanza Superior.La creación  de los materiales multimedia debe fundamentarse en una serie de principios con el objetivo  de facilitar el proceso de aprendizaje de los estudiantes, por ello se debe tener en consideración aspectos como los mecanismos de aprendizaje de la memoria, un  estilo pedagógico o la interacción con los estudiantes. El  diseño instruccional - ADDIE- tendría como objetivo planificar el desarrollo de una política institucional para la elaboración de materiales multimedia.La colaboración en los procesos de enseñanza es uno de los elementos claves en el EEES. Las bibliotecas deberemos establecer mecanismos para desarrollar procesos formativos en competencias informacionales, así como en la elaboración de materiales multimedia
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