48 resultados para Pedro Martínez Montálvez
Resumo:
El presente Proyecto Final de Carrera, titulado “Estudio de la eficiencia energética del sector XXI de la Comunidad de Regantes “San Pedro” de Castelflorite (Huesca)”, tiene como objetivo analizar energéticamente el bombeo del sector XXI de dicha Comunidad de Regantes. El proceso seguido ha consistido en diagnosticar la situación actual, identificar los puntos críticos menos eficientes y establecer una serie de medidas destinadas a gestionar de forma más eficiente y sostenible los recursos energéticos. Estas medidas se han estudiado cuantificando el impacto energético y económico que supondría su implantación, así como su viabilidad.
A priori parameterisation of the CERES soil-crop models and tests against several European data sets
Resumo:
Mechanistic soil-crop models have become indispensable tools to investigate the effect of management practices on the productivity or environmental impacts of arable crops. Ideally these models may claim to be universally applicable because they simulate the major processes governing the fate of inputs such as fertiliser nitrogen or pesticides. However, because they deal with complex systems and uncertain phenomena, site-specific calibration is usually a prerequisite to ensure their predictions are realistic. This statement implies that some experimental knowledge on the system to be simulated should be available prior to any modelling attempt, and raises a tremendous limitation to practical applications of models. Because the demand for more general simulation results is high, modellers have nevertheless taken the bold step of extrapolating a model tested within a limited sample of real conditions to a much larger domain. While methodological questions are often disregarded in this extrapolation process, they are specifically addressed in this paper, and in particular the issue of models a priori parameterisation. We thus implemented and tested a standard procedure to parameterize the soil components of a modified version of the CERES models. The procedure converts routinely-available soil properties into functional characteristics by means of pedo-transfer functions. The resulting predictions of soil water and nitrogen dynamics, as well as crop biomass, nitrogen content and leaf area index were compared to observations from trials conducted in five locations across Europe (southern Italy, northern Spain, northern France and northern Germany). In three cases, the model’s performance was judged acceptable when compared to experimental errors on the measurements, based on a test of the model’s root mean squared error (RMSE). Significant deviations between observations and model outputs were however noted in all sites, and could be ascribed to various model routines. In decreasing importance, these were: water balance, the turnover of soil organic matter, and crop N uptake. A better match to field observations could therefore be achieved by visually adjusting related parameters, such as field-capacity water content or the size of soil microbial biomass. As a result, model predictions fell within the measurement errors in all sites for most variables, and the model’s RMSE was within the range of published values for similar tests. We conclude that the proposed a priori method yields acceptable simulations with only a 50% probability, a figure which may be greatly increased through a posteriori calibration. Modellers should thus exercise caution when extrapolating their models to a large sample of pedo-climatic conditions for which they have only limited information.
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En el presente trabajo vamos a analizar la trayectoria política de dos canónigos, Francisco Martínez Marina y José Espiga y Gadea, partidarios del liberalismo en una época de cambios en la cual, cada uno a su manera, contribuyó a la construcción del Estado liberal constitucional español. Tras las Cortes de Cádiz, estos importantes pensadores fueron perseguidos por el absolutismo y compartieron estancia en la Catedral de Lérida, el seno de la cual abandonaron para participar en las Cortes del Trienio Liberal (1820-1823)
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En septiembre de 1547 asesinaron a Pedro Luis Farnesio, duque de Parma y de Piacenza, hijo del papa Paulo III...
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El estreno de la película Ágora de Alejandro Amenábar en octubre de 2009 puso nuevamente de moda la figura de la célebre filósofa y matemática Hipatia (a quien en rigor deberíamos llamar Hipacia) y generó la aparición de un gran número de monografías, novelas y artículos de todo tipo acerca de su figura. De entre toda esta producción destaca el libro de Clelia Martínez Maza, profesora titular de Historia Antigua de la Universidad de Málaga. Como pone de manifiesto su producción científica, la autora es una gran conocedora del fenómeno religioso y de los conflictos sociales vividos durante la Antigüedad tardía, algo que también puede observarse en la presente obra. Nos hallamos ante una monografía de divulgación culta, como manifiesta la abundante documentación que la autora maneja, aunque el libro carezca de notas tanto al final del volumen como a pie de página, algo normal en estos casos.
Resumo:
The contribution of the propagating and the evanescent waves associated with freely propagating non-paraxial light fields whose transverse component is azimuthally polarized at some plane is investigated. Analytic expressions are derived for describing both the spatial shape and the relative weight of the propagating and the evanescent components integrated over the transverse plane. The analysis is carried out within the framework of the plane-wave angular spectrum approach. These results are used to illustrate the behavior of a kind of donut-like beams with transverse azimuthal polarization at some plane.
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The β site APP cleaving enzyme 1 (BACE1) is the rate-limiting β-secretase enzyme in the amyloidogenic processing of APP and Aβ formation, and therefore it has a prominent role in Alzheimer"s disease (AD) pathology. Recent evidence suggests that the prion protein (PrP) interacts directly with BACE1 regulating its β-secretase activity. Moreover, PrP has been proposed as the cellular receptor involved in the impairment of synaptic plasticity and toxicity caused by Aβ oligomers. Provided that common pathophysiologic mechanisms are shared by Alzheimer"s and Creutzfeldt-Jakob (CJD) diseases, we investigated for the first time to the best of our knowledge a possible association of a common synonymous BACE1 polymorphism (rs638405) with sporadic CJD (sCJD). Our results indicate that BACE1 C-allele is associated with an increased risk for developing sCJD, mainly in PRNP M129M homozygous subjects with early onset. These results extend the very short list of genes (other than PRNP) involved in the development of human prion diseases; and support the notion that similar to AD, in sCJD several loci may contribute with modest overall effects to disease risk. These findings underscore the interplay in both pathologies of APP, Aβ oligomers, ApoE, PrP and BACE1, and suggest that aging and perhaps vascular risk factors may modulate disease pathologies in part through these key players
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Parece mentira que una pieza teatral firmada por Calderón de la Barca haya tardado más de tres cientos años en aparecer impresa y que sea ahora,en el 2010, cuando lo haga por primera vez. ¿A qué se debe esta falta de interés por la obra?La respuestanos la ofrecen Felipe B. Pedza Jiménez y Rafael González Cañal en el capítulo que abre el estudio preliminar de su edicion tulado«Razones de una sin razón»
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The analysis of paraxial Gaussian beams features in most undergraduate courses in laser physics, advanced optics and photonics. These beams provide a simple model of the field generated in the resonant cavities of lasers, thus constituting a basic element for understanding laser theory. Usually, uniformly polarized beams are considered in the analytical calculations, with the electric field vibrating at normal planes to the propagation direction. However, such paraxial fields do not verify the Maxwell equations. In this paper we discuss how to overcome this apparent contradiction and evaluate the longitudinal component that any paraxial Gaussian beam should exhibit. Despite the fact that the assumption of a purely transverse paraxial field is useful and accurate, the inclusion of the above issue in the program helps students to clarify the importance of the electromagnetic nature of light, thus providing a more complete understanding of the paraxial approach.
Resumo:
A comparison is established between the contributions of transverse and longitudinal components of both the propagating and the evanescent waves associated to freely propagating radially polarized nonparaxial beams. Attention is focused on those fields that remain radially polarized upon propagation. In terms of the plane-wave angular spectrum of these fields, analytical expressions are given for determining both the spatial shape of the above components and their relative weight integrated over the whole transverse plane. The results are applied to two kinds of doughnut-like beams with radial polarization, and we compare the behavior of such fields at two transverse planes.
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Acoel flatworms are small marine worms traditionally considered to belong to the phylum Platyhelminthes. However, molecular phylogenetic analyses suggest that acoels are not members of Platyhelminthes, but are rather extant members of the earliest diverging Bilateria. This result has been called into question, under suspicions of a long branch attraction (LBA) artefact. Here we re-examine this problem through a phylogenomic approach using 68 different protein-coding genes from the acoel Convoluta pulchra and 51 metazoan species belonging to 15 different phyla. We employ a mixture model, named CAT, previously found to overcome LBA artefacts where classical models fail. Our results unequivocally show that acoels are not part of the classically defined Platyhelminthes, making the latter polyphyletic. Moreover, they indicate a deuterostome affinity for acoels, potentially as a sister group to all deuterostomes, to Xenoturbellida, to Ambulacraria, or even to chordates. However, the weak support found for most deuterostome nodes, together with the very fast evolutionary rate of the acoel Convoluta pulchra, call for more data from slowly evolving acoels (or from its sister-group, the Nemertodermatida) to solve this challenging phylogenetic problem.
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The genetic impact associated to the Neolithic spread in Europe has been widely debated over the last 20 years. Within this context, ancient DNA studies have provided a more reliable picture by directly analyzing the protagonist populations at different regions in Europe. However, the lack of available data from the original Near Eastern farmers has limited the achieved conclusions, preventing the formulation of continental models of Neolithic expansion. Here we address this issue by presenting mitochondrial DNA data of the original Near-Eastern Neolithic communities with the aim of providing the adequate background for the interpretation of Neolithic genetic data from European samples. Sixty-three skeletons from the Pre Pottery Neolithic B (PPNB) sites of Tell Halula, Tell Ramad and Dja'de El Mughara dating between 8,700-6,600 cal. B.C. were analyzed, and 15 validated mitochondrial DNA profiles were recovered. In order to estimate the demographic contribution of the first farmers to both Central European and Western Mediterranean Neolithic cultures, haplotype and haplogroup diversities in the PPNB sample were compared using phylogeographic and population genetic analyses to available ancient DNA data from human remains belonging to the Linearbandkeramik-Alföldi Vonaldiszes Kerámia and Cardial/Epicardial cultures. We also searched for possible signatures of the original Neolithic expansion over the modern Near Eastern and South European genetic pools, and tried to infer possible routes of expansion by comparing the obtained results to a database of 60 modern populations from both regions. Comparisons performed among the 3 ancient datasets allowed us to identify K and N-derived mitochondrial DNA haplogroups as potential markers of the Neolithic expansion, whose genetic signature would have reached both the Iberian coasts and the Central European plain. Moreover, the observed genetic affinities between the PPNB samples and the modern populations of Cyprus and Crete seem to suggest that the Neolithic was first introduced into Europe through pioneer seafaring colonization.
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This paper shows the relationship between two Spanish writers: Garcilaso de la Vega and Pedro Salinas; or better, the influence of the former over the latter. This influence may be noticed in different levels: the use of literary genres (eclogues, elegies or collections of verse), the conception of love, the use of myths and topics, the music of verse, etc. Some characteristics of Salinas’s style come clearly from Garcilaso (the intimacy, simplicity, orality, the dialogue, the use of the present tense and the first person, etc.). Our essay studies the influence of Garcilaso on the book Largo lamento, 1937?, written by Salinas at the same time as an essay about the renaissance poet —in addition of other unpublished works and his personal correspondence—, in order to show the presence of Garcilaso in his mind and all of his production
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La calidad de vida en la población universitaria adquiere una especial importancia ya que permite obtener información sobre las condiciones de vida de los universitarios y, sobre todo, de cómo éstos las perciben. Objetivo: Evaluar la calidad de vida de los universitarios que cursan estudios en ciencias de la salud y su relación con diferentes factores tales como: hábitos de vida, parámetros antropométricos y la influencia de las distintas variables sobre su percepción. Material y Método: Estudio transversal de una muestra de 1.753 estudiantes de ciencias de la salud de nueve universidades españolas con diseño muestral aleatorio y estatrificado según curso y facultad al que se le aplicó un cuestionaro ad hoc que recogía todas las variables a estudio. Resultados: La calidad de vida percibida por los participantes fue Me = 75. Los factores explorados de la calidad de vida se co-relacionaron significativamente con la percepción global de calidad de vida de los estudiantes (p<0,001). Se establecieron 3 dimensiones y el impacto de cada una de ellas sobre la percepción de calidad de vida global fue p<0,001. Los varones percibieron mejor calidad de vida que las mujeres y también los estudiantes con menor Índice de Masa Corporal (IMC). Conclusión: Los universitarios son una población clave para realizar actividades de promoción y prevención de la salud por lo que resulta necesario crear mejores infraestucturas y recursos educativos para mejorar la CV y fomentar hábitos y estilos de vida saludable con especial atención en la alimentación y la realización de una adecuada actividad física.
Resumo:
In terms of the Fourier spectrum, a simple but general analytical expression is given for the evanescent field associated to a certain kind of non-paraxial exact solutions of the Maxwell equations. This expression enables one to compare the relative weight of the evanescent wave with regard to the propagating field. In addition, in those cases in which the evanescent term is significant, the magnitude of the field components across the transverse profile (including the evanescent features) can be determined. These results are applied to some illustrative examples.