2,444 research outputs found
Configuración Software de la directividad de arrays lineales
A line array can be defined as a column of
loudspeakers that is designed so that these work together to achieve a higher directivity. This paper presents an application that enables a user to rotate the wavefront of uniform line arrays. Theoretical background and details of the
implementation are provided. The validity of the application is tested with measurements of the directivity that are also compared with simulations.Este trabajo ha sido financiado Universidad de Málaga. Campus de Excelencia Internacional AndalucÃa Tech y el grupo de investigación Aplicación de las TecnologÃas de la Información y Comunicaciones (PAI TIC-208)
Epifisiolisis de cabeza de radio asociadas a luxación de codo y reducción espontánea
Realizamos un estudio retrospectivo de 10 casos de la epifisiolisis de cabeza de radio ocurridas durante el periodo 1992 a 1997, con un desplazamiento mayor de 60º que según los criterios de O'Brien corresponderÃan a un grado III. De todas las revisadas seleccionamos 6 casos en los que habÃa una angulación mayor de 90º, creemos ocurren después de luxación o reducción espontánea de luxación de codo; por ser las más frecuentes, las que más problemas presentan en el tratamiento y las que producen más secuelas. Nuestro objetivo es valorar los resultados obtenidos con nuestros tratamientos y realizar una revisión bibliográfica.We have done a retrospective study of ten cases of radial head epiphysiolysis occurred between 1992 and 1997, displaced more than 60º. (O'Brien's grade III). Amongst them we have selected those which were displaced more than 90º (six cases) probably occurred after an elbow luxation or after the spontaneous reduction of an elbow luxation; because the are more infrequent, more troublesome and they give more secuelae. Our aim is to evaluate the results obtained with the treatment and to review the literature
Use of datasets derived from time-series AVHRR imagery as surrogates for land cover maps in predicting species' distributions
We hypothesized that NDVI time-series composite
imagery or clustered data derived from the NDVI time series could
serve as effective surrogates for land cover data in predictive
modeling of species’ ecological niches and potential geographic
distributions. Using two Mexican bird species, we examined our
hypothesis with GARP, the Genetic Algorithm for Rule-set
Prediction. Inputs included topographic and climate data, as well as
the NDVI and clustered NDVI datasets. We used a land cover map
previously derived from the NDVI dataset for comparison testing.
Considering only topographic factors, we found that the NDVI or
clustered NDVI data performed as well as or better than the land
cover data. When climate data were added, the land cover data
performed better than the NDVI data, but improvements were slight
Towards an increase of flash flood geomorphic effects due to gravel mining and ground subsidence in Nogalte stream (Murcia, SE Spain)
Transition from endorheic alluvial fan environments to well-channelized fluvial systems in natural conditions may occur in response to base-level fluctuations. However, human-induced changes in semi-arid regions can also be responsible for similar unforeseen modifications. Our results confirm that in-channel gravel mining and aquifer overexploitation over the last 50 years in the case study area have changed the natural stability of the Nogalte stream and, as a result, its geomorphic parameters including channel depth and longitudinal profile have begun to adapt to the new situation. Using interferometric synthetic aperture radar (InSAR) data we obtain maximum values for ground subsidence in the Upper GuadalentÃn Basin of  ∼ 10 cm yr−1 for the period 2003–2010. In this context of a lowered base level, the river is changing its natural flood model to a more powerful one. A comparison of the 1973 flood event, the most dramatic flood event ever recorded in the area, with the 2012 event, where there was a similar discharge but a sediment load deficit, reveals greater changes and a new flooding pattern and extension. In-channel gravel mining may be responsible for significant local changes in channel incision and profile. This, together with the collateral effects of aquifer overexploitation, can favour increased river velocity and stream power, which intensify the consequences of the flooding. The results obtained here clearly demonstrate an existing transition from the former alluvial pattern to a confined fluvial trend, which may become more pronounced in the future due to the time lag between the drop in aquifer level and ground subsidence, and introduce a new scenario to be taken into consideration in future natural hazard planning in this area.s. This research was partially
funded by projects CGL 2011-23857, ESP2013-47780-C2-2-R
and CGL2013-47412-C2-1-P (Spanish Ministry of Economy
and Competitiveness).Peer reviewe
Concentración de nutrientes en la escorrentÃa de diferentes predios del trópico enmendados con residuos animales bajo condiciones de lluvia natural.
Excessive nutrient losses from agricultural soils represent a major source of surface water contamination. In this study we quantified concentrations of total Kjeldahl nitrogen (TKN), dissolved and total phosphorus (DP,TP), and dissolved organic carbon (DOC) in runoff from two animal farm operations of Puerto Rico. The farms, one dairy and one poultry, represented typical conditions (i.e., topography, ecological zone, management system) of these production systems.Two fields were selected for the runoff studies on each farm, and two runoff collectors were installed in each field. Runoff samples were collected under natural rainfall conditions. The average phosphorus concentration in runoff from the poultry fields (5.87 mg TP/L, 4.82 mg DP/L) was significantly greater than that observed from the dairy fields (2.29 mg TP/L, 1.79 mg DP/L). Dissolved phosphorus concentrations represented more than 90% of the total P concentrations on both farms, a situation that may exacerbate the impact on receiving water bodies. Average DP concentrations exceeded 1 mg/L, a limit proposed for the regulation of runoff P concentrations from agricultural lands, in 70% of the runoff events at the dairy farm, and 100% of the events at the poultry farm. The magnitude of the nutrient concentrations on both farms was significantly affected by the time lapse between the manure applications and the first precipitation event. Nutrient concentrations in runoff samples were also significantly affected by rainfall depth.La pérdida excesiva de nutrientes de suelos agrÃcolas representa una fuente primaria de contaminación de los cuerpos de agua. En este estudio se cuantificaron las concentraciones de nitrógeno total Kjeldahl (NTK), fósforo total y disuelto (PD, PT), y carbón orgánico disuelto (COD) en la escorrentÃa de dos fincas productoras de animales de Puerto Rico. Las fincas, una vaquerÃa y una avÃcola, son representativas de las condiciones tÃpicas (i.e., topografÃa, zona ecológica, sistema de manejo) de estos sistemas de producción. En cada finca se seleccionaron dos predios para estudios de escorrentÃa y en cada predio se instalaron dos fraccionadores de escorrentÃa. Se recolectaron muestras de escorrentÃa generadas por eventos de lluvia natural. La concentración promedio de fósforo en la escorrentÃa de los predios avÃcolas (5.87 mg TP/L, 4.82 mg PD/L) fue significativamente mayor que la observada en los predios de la vaquerÃa (2.29 mg PT/L, 1.79 mg PD/L). La concentración de PD representó cerca del 90% de la concentración de PT observada en ambas fincas, situación que puede agravar el impacto en las aguas circundantes. La concentración de PD promedio excedió 1 mg/L, lÃmite propuesto para controlar la escorrentÃa de fósforo de predios agrÃcolas, en 70% de los eventos de escorrentÃa en el caso de la vaquerÃa y en un 100% de los casos en la finca avÃcola. La magnitud de las concentraciones en ambas fincas se afectó significativamente por el lapso de tiempo transcurrido entre la aplicación de los residuos orgánicos y el primer evento de lluvia. La concentración de nutrientes en la escorrentÃa también se afectó significativamente con la profundidad de la lámina de lluvia
Guiding signs in metabolic disease diagnosis
Los errores innatos del metabolismo son un grupo de enfermedades genéticas con sintomatologÃa muy inespecÃfica y por tanto difÃcil diagnóstico si no existe una sospecha clÃnica elevada. Sin embargo existen algunos datos de la exploración fÃsica y de las pruebas complementarias que pueden enfocar el proceso diagnóstico hacia la solicitud de pruebas especÃficas que lo confirmen. El caso que presentamos trata de destacar algunos de estos datos que pueden hacer sospechar la existencia de un defecto congénito de la glucosilación de proteÃnas, trastorno infrecuente pero con algunas formas tratables, por lo que su sospecha y diagnóstico precoz es de vital importanciaInborn errors of metabolism are a group of genetic diseases with non specific symptoms and therefore difficult to diagnose without high clinical suspicion. However there are some physical examination data and laboratory tests that can focus the diagnostic process to the implementation of specific tests to confirm them. The case exposed highlights some of these data that can make us suspect the existence of a congenital defect of glycosylation of proteins, rare disorder but with some treatable variations, that make their suspicion and early diagnosis of great importanc
Hill-climbing and brute-force attacks on biometric systems: A case study in match-on-card fingerprint verification
Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. M. MartÃnez-DÃaz, J. Fiérrez-Aguilar, F. Alonso-Fernández, J. Ortega-GarcÃa, J.A. Siguenza, "Hill-Climbing and Brute-Force Attacks on Biometric Systems: A Case Study in Match-on-Card Fingerprint Verification" in Proceedings of 40th Annual IEEE International Carnahan Conferences Security Technology ICCST, Lexington, KY (USA), 2006, 151 - 159In this paper, we study the robustness of state-of-the-art automatic fingerprint verification systems against hill climbing and brute-force attacks. We compare the performance of this type of attacks against two different minutiae-based systems, the NIST Fingerprint Image Software 2 (NFIS2) reference system and a Match-on-Card based system. In order to study their success rate, the attacks are analyzed and modified in each scenario. We focus on the influence of initial conditions in hill-climbing attacks, like the number of minutiae in the synthetically generated templates or the performance of each type of modification in the template. We demonstrate how slight modifications in the hill-climbing algorithm lead to very different success ratesThis work has been supported by the Spanish Ministry of Defense, BioSecure NoE and the TIC2003-08382-C05-01 project of the Spanish Ministry of Science and Technolog
Servidor de datos y página web para el aprendizaje de SIG en la ingenierÃa forestal
Los Sistemas de Información geográfica (SIG) son una herramienta de trabajo habitual en el ámbito de la ingenierÃa forestal, tanto en la faceta de redacción de proyectos, como en la investigación sobre el medio ambiente y el territorio. Cada vez hay más información cartográfica disponible desde servidores de diferentes instituciones, por lo que consideramos que es muy útil contar con una herramienta de organización de la información. En el trabajo que se presenta, se pretende proporcionar a los estudiantes e investigadores en materia forestal un portal que contenga información actualizada y ordenada sobre los recursos existentes compatibles con los SIG. Por tanto constituiráuna herramienta de apoyo que facilitarála fase de documentación, búsqueda de datos compatibles y aprendizaje de las herramientas que sirven de base para el desarrollo de cualquier trabajo técnico o de investigación relacionado con el medio ambiente y el territorio que se apoye en los SIG
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