3,148 research outputs found

    Análisis antropológico de "El ángel exterminador"

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    Depto. de Antropología Social y Psicología SocialFac. de Ciencias Políticas y SociologíaFALSEunpu

    La digitalización del pensamiento. Implicaciones en la transmisión de la cultura.

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    Este trabajo recoge unas reflexiones sobre el impacto de las Nuevas Tecnologías de la Información y la Comunicación (NTIC) en nuestra sociedad, y lo que puede representar, tal como lo hizo en su momento la aparición de la escritura o la imprenta, en cuanto a la transformación del ser humano actual. En concreto, se plantea la necesidad de realizar una etnografía virtual desde la antropología, como disciplina que maneja unas herramientas de índole cualitativa que pueden servir para desentrañar, en el ámbito de la enseñanza, qué nuevos significados y valores están en juego en las relaciones dentro de la transmisión y adquisición de los conocimientos en el llamado ciberespacio, lugar de ingente producción de información que hará cambiar, probablemente, el concepto actual de alfabetización

    Terahertz surface plasmon polariton propagation and focusing on periodically corrugated metal wires

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    In this letter we show how the dispersion relation of surface plasmon polaritons (SPPs) propagating along a perfectly conducting wire can be tailored by corrugating its surface with a periodic array of radial grooves. In this way, highly localized SPPs can be sustained in the terahertz region of the electromagnetic spectrum. Importantly, the propagation characteristics of these spoof SPPs can be controlled by the surface geometry, opening the way to important applications such as energy concentration on cylindrical wires and superfocusing using conical structures.Comment: accepted at PRL, submitted 29th May 200

    Scattering of surface plasmons by one-dimensional periodic nanoindented surfaces

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    In this work, the scattering of surface plasmons by a finite periodic array of one-dimensional grooves is theoretically analyzed by means of a modal expansion technique. We have found that the geometrical parameters of the array can be properly tuned to achieve optimal performance of the structure either as a Bragg reflector or as a converter of surface plasmons into light. In this last case, the emitted light is collimated within a few degrees cone. Importantly, we also show that a small number of indentations in the array are sufficient to fully achieve its functional capabilities.Comment: 5 pages, 5 figures; changed sign convention in some definition

    Optical bistability in subwavelength apertures containing nonlinear media

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    We develop a self-consistent method to study the optical response of metallic gratings with nonlinear media embedded within their subwavelength slits. An optical Kerr nonlinearity is considered. Due to the large E-fields associated with the excitation of the transmission resonances appearing in this type of structures, moderate incoming fluxes result in drastic changes in the transmission spectra. Importantly, optical bistability is obtained for certain ranges of both flux and wavelength.Comment: 4 pages, 4 figure

    Influencia de la práctica clínica en la presencia de puntos gatillo miofasciales en el músculo trapecio de estudiantes de enfermería. Estudio longitudinal descriptivo.

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    Aim: To observe whether the tasks performed by nursing students during their third year of nursing degrees have an influence on the state of MTP of their trapezius muscle.Participants and Methods: 30 third-year students from Alcalá de Henares University College of Nursing were evaluated. Exclusion criteria: to suffer any sense or trophic muscular disorder, to have begun or be receiving any influential treatment. A questionnaire about the types of tasks they carry out and other sociodemographic and academical work factors were done. Students were assessed to check the presence of some MTP in their trapezius, describing its active or dormant state through diagnostic criteria, their pressure pain threshold (measured with an algometer) and active ranges of cervical movements were also recorded. All measurements were taken before and after one month of the experiment. Through the statistical analysis the data collected in the questionnaire was compared with the state of the MTP in both moments, with a p<0.05 and a 95% confidence interval.Results: all the subjects were women who over the course of the experiment recorded a 1.8- upper scoring on the visual analogue scale, they showed an average increase of 1.55º in the cervical ranges of motion, except flexion; and the pressure pain threshold rose an average 0.139 kg/cm2. Trigger points (TP) 1 and 2 changed from dormant to active state on 6,7% of the subjects, and the TP5 on 3,3%. At the end of the experiment the TP6 appeared as 6,7% of them.Conclusions: tendencies have been observed among the analyzed variables which allow the proposition of more specific studies about biological and socio-labour factors linked to MTPs in order to establish physio-therapeutic efficient strategies for incorporation into the professional world.Objetivo: Observar si la práctica clínica de estudiantes de enfermería influye en el estado de PGM en el trapecio.Participantes y métodos: Estudio longitudinal descriptivo en el que se evaluaron 30 estudiantes de tercero de la Escuela Universitaria de Enfermería de Alcalá de Henares. Criterios de inclusión: iniciar su primer período de prácticas tras la primera sesión de valoración. Criterios de exclusión: presentar alteración muscular sensitiva o trófica, estar realizando o iniciar algún tratamiento influyente. Se pasó un cuestionario sobre tareas desempeñadas en sus prácticas clínicas y otros factores sociodemográficos y del entorno académico-laboral. Se valoraron: la presencia de puntos gatillo miofasciales (activos y latentes) en el trapecio según criterios diagnósticos, el umbral de dolor a la presión (con algómetro), y los rangos de movimiento cervical activo. Todas las medidas se tomaron antes y después de un mes de prácticas. En el análisis estadístico se compararon los datos recopilados en el cuestionario con el estado de los PGM en los dos momentos, considerando una p<0.05 y el intervalo de confianza del 95%.Resultados: Todos los participantes fueron mujeres, que tras el período de prácticas clínicas, registraron una puntuación 1.8 superior en la escala analógica visual, mostraron un incremento medio de 1,55º en los rangos de movimiento cervical, salvo en la flexión; y el umbral de dolor a la presión aumentó de media 0.139 kg/cm2. Los PG 1 y 2 cambiaron de estado latente a activo en un 6,7% de sujetos, y el PG 5 en un 3,3%. Al final del período el PG6 apareció en el 6,7%.Conclusiones: Se han observado tendencias en las variables analizadas que permiten plantear el estudio más específico de factores biológicos y sociolaborales influyentes en la presencia de PGM, para establecer estrategias fisioterápicas eficientes antes de la incorporación al ámbito profesional

    Optimal design and planning multi resource-based energy integration in process industries

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    Recently, process industries have experienced a significant pressure to shift from centralized energy supplying systems to the in-situ exploitation of renewable resources. Special attention has been paid to multi resource-based energy systems, a particular case of distributed generation where processing nodes include energy generation and can operate either grid-connected or isolated. This work proposes a general model to determine the optimal retrofitting of a supply chain integrating renewable energy sources under uncertain conditions and to analyze the effect of different planning horizons in the solution. The proposed mixed integer linear programming (MILP) formulation allows determining the best combination of available technologies that satisfies the internal energy demand of a given set of scenarios while addressing total expected cost and expected environmental impact minimization. The potential of the approach is illustrated through a case study from the sugar cane industry proposed by Mele et al. (2011).Peer ReviewedPostprint (author's final draft
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