83 research outputs found
Adaptive Vectorial Filter for Grid Synchronization of Power Converters Under Unbalanced and/or Distorted Grid Conditions
This paper presents a new synchronization scheme for detecting multiple positive-/negative-sequence frequency harmonics in three-phase systems for grid-connected power converters. The proposed technique is called MAVF-FLL because it is based on the use of multiple adaptive vectorial filters (AVFs) working together inside a harmonic decoupling network, resting on a frequency-locked loop (FLL) which makes the system frequency adaptive. The method uses the vectorial properties of the three-phase input signal in the αβ reference frame in order to obtain the different harmonic components. The MAVF-FLL is fully designed and analyzed, addressing the tuning procedure in order to obtain the desired and predefined performance. The proposed algorithm is evaluated by both simulation and experimental results, demonstrating its ability to perform as required for detecting different harmonic components under a highly unbalanced and distorted input grid voltage
Watermelon Juice: Potential Functional Drink for Sore Muscle Relief in Athletes
L-Citrulline is an excellent candidate to reduce muscle soreness, and watermelon is a fruit rich in this amino acid. This study investigated the potential of watermelon juice as a functional drink for athletes. An in vitro study of intestinal absorption of l-citrulline in Caco-2 cells was performed using unpasteurized (NW), pasteurized (80 °C for 40 s) watermelon juice (PW) and, as control, a standard of l-citrulline. l-citrulline bioavailability was greater when it was contained in a matrix of watermelon and when no heat treatment was applied. In the in vivo experiment (maximum effort test in a cycloergometer), seven athletes were supplied with 500 mL of natural watermelon juice (1.17 g of l-citrulline), enriched watermelon juice (4.83 g of l-citrulline plus 1.17 g from watermelon), and placebo. Both watermelon juices helped to reduce the recovery heart rate and muscle soreness after 24 h.Actividad Física y Deport
Prevención del consumo de drogas en los estudiantes de la Universidad de Huelva. Estudio de sus motivaciones, hábitos y ocupación del tiempo de ocio
La drogodependencia ha adquirido en los últimos años unas dimensiones alarmantes, afectando de manera especial a la población adolescente y juvenil de nuestra sociedad, además de familiares, amigos, vecinos y a todo aquél que directa o indirectamente ha sido sacudido con el azote de la droga. Para Castillo y Díaz (2006), conceptualmente la drogodependencia es un fenómeno continuo en el tiempo, en evolución permanente, tanto en lo referente a sustancias consumidas, como a las modalidades de consumo y al patrón tipo de consumidor. La dependencia de las drogas, en sus múltiples variantes, es un problema que resulta complejo, debido a la amplitud de los factores y a la diversidad de situaciones que confluyen en su aparición y las repercusiones que ello conlleva. La situación de la drogodependencia no puede entenderse de forma aislada o como problemática puntual. Para muchos autores y expertos en la materia es fruto de tres variables: una sustancia, un sujeto y un contexto sociocultural. Básicamente, desde este trabajo tratamos de indagar en aspectos relacionados con el consumo de drogas, tal y como regularmente se viene haciendo desde otros estudios de periodicidad bianual, tales como «Los andaluces antes las drogas» que la Consejería para la Igualdad y Bienestar Social de la Junta de Andalucía viene realizando desde 1987 ⎯siendo el último informe el publicado en 2008 bajo el título «La población andaluza ante las drogas, X»⎯, la «Encuesta domiciliaria sobre alcohol y drogas en España», realizada desde 1995 por el Plan Nacional sobre Drogas; la «Encuesta escolar sobre consumo de drogas», que también viene realizando el Plan Nacional sobre Drogas desde 1996 ⎯siendo la última realizada en 2006 bajo el nombre de «Encuesta estatal sobre uso de drogas en estudiantes de Secundaria»⎯, y los informes anuales del Observatorio Europeo sobre Drogodependencias y Toxicomanías (OEDT), entre otros muchos estudios más. Estos estudios se dedican a indagar sobre cuestiones relativas al consumo de drogas, tales como edad de inicio, frecuencia del consumo, tipo de sustancias consumidas, ocupación del ocio, razones del consumo y no consumo, lugares y momentos, consecuencias, etc
Effects of small-sided exercises on body composition and maximal oxygen uptake in adolescents
Background: The regular practice of physical activity contributes to weight control and improves maximal oxygen uptake (VO2max), socialization and quality of life. Aim: To determine the effect of moderate-to-vigorous physical activity on body composition and VO2max in a group of overweight school-age males. Material and Methods: We studied fifty-five overweight males aged 15.6 ± 0.7 years. Participants were divided in two groups (experimental and control groups). The intervention in the experimental group was the practice of small-sided games during 60 minutes, two days per week and during 11 weeks. At baseline and the end of the intervention, body composition was measured using bioimpedance and VO2max was calculated using the Course Navette test. Results: A 7% reduction in the percentage of body fat and a 9% increase in VO2max were observed in the experimental group (p < 0.01). No changes were recorded in the control group. Conclusions: Eleven weeks of small-sided exercises performed twice per week increased VO2max and reduced fat mass in overweight adolescents
Coro Trasito (Tella-Sin, Huesca): una cueva redil del Neolítico Antiguo en la alta montaña
En este trabajo se presentan los resultados preliminares de las intervenciones arqueológicas llevadas a cabo en la Cueva de Coro Trasito, situada en el Pirineo central aragonés, dentro del municipio de Tella-Sin, Huesca. Estas intervenciones corresponden tanto a los sondeos llevados a cabo durante el 2011 y el 2013, como la excavación en extensión de la parte central de la cueva, aproximadamente de unos 70m2, durante las campañas de 2014 y 2015. Estos trabajos han permitido documentar una secuencia de ocupaciones neolíticas de la cueva datadas entre 5300 y 4600 cal ANE, sucedidas por una última fase prehistórica de mediados del II Milenio cal ANE.
De esta forma, repasaremos los principales hallazgos que se han documentado en las diferentes campañas arqueológicas, materiales líticos, cerámicos, así como los diferentes estudios realizados sobre la fauna y la carpología provenientes del sondeo nº 3 (2013). Así mismo, presentaremos algunas de las características más relevantes de la excavación en extensión de la cueva, así como las diferentes estructuras documentadas asociadas al Neolítico Medio. Estas evidencias, junto con los estudios que se han llevado a cabo hasta este momento, nos hacen intuir que la ocupación de la cueva durante este periodo fue recurrente y con una economía plenamente neolítica.Peer Reviewe
Local wind speed forecasting based on WRF-HDWind coupling
[EN] Wind speed forecasts obtained by Numerical Weather Prediction models are limited for fine interpretation in
heterogeneous terrain, in which different roughnesses and orographies occur. This limitation is derived from the
use of low-resolution and grid-box averaged data. In this paper a dynamical downscaling method is presented to
increase the local accuracy of wind speed forecasts. The proposed method divides the wind speed forecasting
into two steps. In the first one, the mesoscale model WRF (Weather Research and Forecasting) is used for getting
wind speed forecasts at specific points of the study domain. On a second stage, these values are used for feeding
the HDWind microscale model. HDWind is a local model that provides both a high-resolution wind field that
covers the entire study domain and values of wind speed and direction at very located points. As an example of
use of the proposed method, we calculate a high-resolution wind field in an urban-interface area from Badajoz, a
South-West Spanish city located near the Portugal border. The results obtained are compared with the values
read by a weathervane tower of the Spanish State Meteorological Agency (AEMET) in order to prove that the
microscale model improves the forecasts obtained by the mesoscale model
Low-count monoclonal B-cell lymphocytosis persists after seven years of follow up and is associated with a poorer outcome
[EN]Low-count monoclonal B-cell lymphocytosis is defined by the presence
of very low numbers of circulating clonal B cells, usually phenotypically
similar to chronic lymphocytic leukemia cells, whose
biological and clinical significance remains elusive. Herein, we re-evaluated
65/91 low-count monoclonal B-cell lymphocytosis cases (54 chronic
lymphocytic leukemia-like and 11 non-chronic lymphocytic leukemialike)
followed-up for a median of seven years, using high-sensitivity
flow cytometry and interphase fluorescence in situ hybridization.
Overall, the clone size significantly increased in 69% of low-count monoclonal
B-cell lymphocytosis cases, but only one subject progressed to
high-count monoclonal B-cell lymphocytosis. In parallel, the frequency
of cytogenetic alterations increased over time (32% vs. 61% of cases,
respectively). The absolute number of the major T-cell and natural killer
cell populations also increased, but only among chronic lymphocytic
leukemia-like cases with increased clone size vs. age- and sex-matched
controls. Although progression to chronic lymphocytic leukemia was
not observed, the overall survival of low-count monoclonal B-cell lymphocytosis
individuals was significantly reduced vs. non-monoclonal Bcell
lymphocytosis controls (P=0.03) plus the general population from
the same region (P≤0.001), particularly among females (P=0.01); infection
and cancer were the main causes of death in low-count monoclonal
B-cell lymphocytosis. In summary, despite the fact that mid-term progression
from low-count monoclonal B-cell lymphocytosis to high-count
monoclonal B-cell lymphocytosis and chronic lymphocytic leukemia
appears to be unlikely, these clones persist at increased numbers, usually
carrying more genetic alterations, and might thus be a marker of an
impaired immune system indirectly associated with a poorer outcome,
particularly among females
Improvement of Fatigue Life and Surface Properties of Metallic Materials of Biomedical Interest by Laser Shock Processing
Laser Shock Processing (LSP) is developed as a technique allowing the effective induction of residual stresses fields in metallic materials allowing a high degree of surface material protection against fatigue crack propagation, abrasive wear, chemical corrosion and other failure conditions, what makes the technique specially suitable and competitive with presently use techniques for the treatment of heavy duty components in the aeronautical, nuclear and automotive industries. The highly beneficial effect of LSP treatments has been demonstrated in the extension of life of test specimens with induced surface notches. The application of the LSP treatment to concrete high reliability components, particularly in the field of metallic materials of biomedical interest is envisaged. In the present communication, several experimental examples of the effects introduced in this kind of materials are shown along with some computational design tools developed in relation with typical prosthetical components. Additionally, the prospects for the application of the LSP treatment to new/advanced materials of biomedical interest are discussed
La explotación de las cimas. Ocupación e impacto humano en las zonas alpinas de los Pirineos al final del Neolítico
En los últimos años se ha constatado arqueológicamente la presencia humana en el Pirineo axial desde inicios del Holoceno, que se incrementa especialmente durante el Neolítico. Con un escaso desfase con respecto a la cronología de las primeras ocupaciones neolíticas del Piedemonte y del Prepirineo, se han documentado diversos yacimientos en fondos de valle del área axial y en laderas entre los 1400 y los 1800 metros de altitud, ocupados desde el V y IV milenios cal ANE. Las últimas investigaciones confirman, además, un incremento del número de asentamientos durante el tercer milenio cal ANE en diversos puntos de la región central de los Pirineos en cotas que, en ocasiones, superan los 2.300 metros de altura. Paralelamente, los datos paleoambientales muestran las primeras señales de impacto humano sobre el medio, como por ejemplo descensos de las formaciones forestales o un incremento de las evidencias de las aperturas de pastos. En definitiva, parece que es a partir del final del Neolítico cuando se establece una explotación ganadera de las áreas alpinas y la franja superior de los pisos subalpinos, iniciando un proceso que ganará en intensidad durante el II milenio cal ANE. Esta presentación aborda la discusión del fenómeno del poblamiento en las zonas altas de la sierra, procurando evitar apriorismos relacionados con el determinismo medioambiental. Para eso, entendemos imprescindible la comparación y contrastación de los datos arqueológicos y la información paleoecológica, con el objetivo de entender, de forma integrada, la evolución del paisaje, de las sociedades y del impacto que éstas produjeron sobre el territorio.Peer reviewe
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