1,462 research outputs found

    Strain balanced quantum posts

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    Quantum posts are assembled by epitaxial growth of closely spaced quantum dot layers, modulating the composition of a semiconductor alloy, typically InGaAs. In contrast with most self-assembled nanostructures, the height of quantum posts can be controlled with nanometer precision, up to a maximum value limited by the accumulated stress due to the lattice mismatch. Here we present a strain compensation technique based on the controlled incorporation of phosphorous, which substantially increases the maximum attainable quantum post height. The luminescence from the resulting nanostructures presents giant linear polarization anisotropy.Comment: Submitted to Applied Physics Letters (7th March 2011). 4 pages, 4 figure

    Metallurgical vessels from the Phoenician site of La Fonteta (Alicante, Spain): a typological and analytical study

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    In G. Körlin, M. Prange, T. Stöllner & Ü. Yalçın (eds.), From bright ores to shiny metals. Festschrift for Andreas Hauptmann on the Occasion of 40 Years Research in Archaeometallurgy and Archaeometry. Der Anschnitt, Beiheft 29, Bochum

    Internal evaluation of a physically-based distributed model using data from a Mediterranean mountain catchment

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    An evaluation of the performance of a physically-based distributed model of a small Mediterranean mountain catchment is presented. This was carried out using hydrological response data, including measurements of runoff, soil moisture, phreatic surface level and actual evapotranspiration. <i>A-priori</i> model parameterisation was based as far as possible on property data measured in the catchment. Limited model calibration was required to identify an appropriate value for terms controlling water loss to a deeper regional aquifer. The model provided good results for an initial calibration period, when judged in terms of catchment discharge. However, model performance for runoff declined substantially when evaluated against a consecutive, rather drier, period of data. Evaluation against other catchment responses allowed identification of the problems responsible for the observed lack of model robustness in flow simulation. In particular, it was shown that an incorrect parameterisation of the soil water model was preventing adequate representation of drainage from soils during hydrograph recessions. This excess moisture was then being removed via an overestimation of evapotranspiration. It also appeared that the model underestimated canopy interception. The results presented here suggest that model evaluation against catchment scale variables summarising its water balance can be of great use in identifying problems with model parameterisation, even for distributed models. Evaluation using spatially distributed data yielded less useful information on model performance, owing to the relative sparseness of data points, and problems of mismatch of scale between the measurement and the model grid.</p> <p style='line-height: 20px;'><b>Keywords: </b>physically-based distributed model, SHETRAN, parameterisation, Mediterranean mountain catchment, internal evaluation, multi-respons

    Development of an acoustic transceiver for the KM3NeT positioning system

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    [EN] In this paper we describe an acoustic transceiver developed for the KM3NeT positioning system. The acoustic transceiver is composed of a commercial free flooded transducer, which works mainly in the 20-40 kHz frequency range and withstands high pressures (up to 500 bars). A sound emission board was developed that is adapted to the characteristics of the transducer and meets all requirements: low power consumption, high intensity of emission, low intrinsic noise, arbitrary signals for emission and the capacity of acquiring the receiving signals with very good timing precision. The results of the different tests made with the transceiver in the laboratory and shallow sea water are described, as well as, the activities for its integration in the Instrumentation Line of the ANTARES neutrino telescope and in a NEMO tower for the in situ tests. © 2012 Elsevier B.V. All rights reserved.This work has been supported by the Ministerio de Ciencia e Innovacion (Spanish Government), Project references FPA2009-13983-C02-02, ACI2009-1067, AIC10-D-00583, and Consolider-Ingenio Multidark (CSD2009-00064). It has also been funded by Generalitat Valenciana, Prometeo/2009/26, and the European 7th Framework Programme, Grant no. 212525.Larosa, G.; Ardid Ramírez, M.; Llorens Alvarez, CD.; Bou Cabo, M.; Martínez Mora, JA.; Adrián Martínez, S.; KM3NeT Consortium (2013). Development of an acoustic transceiver for the KM3NeT positioning system. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 725:215-218. https://doi.org/10.1016/j.nima.2012.11.167S21521872

    Human or Computer Assisted Interactive Transcription: Automated Text Recognition, Text Annotation, and Scholarly Edition in the Twenty-First Century

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    Computer assisted transcription tools can speed up the initial process of reading and transcribing texts. At the same time, new annotation tools open new ways of accessing the text in its graphical form. The balance and value of each method still needs to be explored. STATE, a complete assisted transcription system for ancient documents, was presented to the audience of the 2013 International Medieval Congress at Leeds. The system offers a multimodal interaction environment to assist humans in transcribing ancient documents: the user can type, write on the screen with a stylus, or utter a word. When one of these actions is used to correct an erroneous word, the system uses this new information to look for other mistakes in the rest of the line. The system is modular, composed of different parts: one part creates projects from a set of images of documents, another part controls an automatic transcription system, and the third part allows the user to interact with the transcriptions and easily correct them as needed. This division of labour allows great flexibility for organising the work in a team of transcribers.Las herramientas de ayuda a la transcripción automática pueden acelerar el proceso inicial de la lectura y transcripción de textos. Al mismo tiempo, las nuevas herramientas de anotación aportan nuevas formas de acceder al texto en su forma original gráfica. Sin embargo, todavía es necesario evaluar las bondades y capacidades de los distintos métodos. STATE, un completo sistema de asistencia a la transcripción de documentos antiguos, se presentó a la audiencia del International Medieval Congress de 2013 celebrado en Leeds. El sistema ofrece un entorno de interacción multimodal para ayudar a las personas en la transcripción de documentos antiguos: el usuario puede teclear, escribir en la pantalla con un lápiz óptico o corregir usando la voz. Cada vez que el usuario cambia de esta forma una palabra, el sistema utiliza la corrección para buscar errores en el resto de la línea. El sistema está dividido en diferentes módulos: uno crea proyectos a partir de un conjunto de imágenes de documentos, otro módulo controla el sistema de transcripción automática, y un tercer módulo permite al usuario interactuar con las transcripciones y corregirlas fácilmente cuando sea necesario. Esta división de las tareas permite una gran flexibilidad para organizar el trabajo de los transcriptores en equipo

    El balneario de Busot (1780-1820)

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    Durante los últimos años del siglo XVIII y primeros del XIX, los Baños de Busot, pertenecientes al término municipal de Alicante, experimentaron una transformación con repercusiones tanto en el ámbito sanitario como social. El consistorio dirigió una serie de obras, mediante las cuales su ruinoso estado evolucionó hasta que en 1818, se abrieron oficialmente al público sus instalaciones. Tanto la procedencia de las personas que acudían a estos Baños como los oficios que se generaron en ellos, nos permiten acceder a un mayor conocimiento de la sociedad alicantina.During the last years of the eighteeth century and early nineteenth, the «Baths of Busot» belonged to the municipality of Alicante and experimented a transformation with implications both in health as social background. The municipality consistory channels a series of works and by its, the ruinous state of the spa evolved. In 1818, the spa was officially opened to the public. The study of people who went to the baths and who worked there, gives us a greater understanding of the Alicante society

    Endovascular Treatment for Pseudoaneurysms after Surgical Correction of Aortic Coarctation

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    Late complications after surgical repair of aortic coarctation are not uncommon. Among these complications pseudoaneurysms are the most frequent complications, occurring between 3 and 38%. Reoperation in these patients is associated with high morbidity and mortality. In the last decade, endovascular techniques emerged as an alternative to conventional surgery with excellent results. We report the case of two patients who presented with pseudoaneurysms after surgical correction for aortic coarctation, which were treated by endovascular means
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