810 research outputs found
Contrasting human perceptions of and attitudes towards two threatened small carnivores, Lycalopex fulvipes and Leopardus guigna, in rural communities adjacent to protected areas in Chile
Indexación: Scopus.The interaction between humans and small carnivores is a phenomenon especially frequent in rural fringes, as is the case of communities surrounding natural areas. In Chile, two species of threatened carnivores, the Darwin's Fox and the Guigna, have increased their contact with humans due to human-induced changes in their habitat. The objective of this study was to characterize the interactions of these species with humans by assessing human perceptions and attitudes toward them, and to assess livestock and poultry ownership and management practices in local communities to evaluate their possible roles in the phenomenon. We conducted semi-structured interviews in rural communities adjacent to natural protected areas of two different regions in southern Chile. We found that people have a more positive perception of Darwin's Foxes than Guignas, but both species are considered damaging due to poultry attacks. Livestock and poultry management was generally deficient. Improvements in animal management and education programs could lead to a significant decrease in negative interactions. © Sacristan et al. 2018.https://www.threatenedtaxa.org/index.php/JoTT/article/view/4030/442
Air gap influence on the vibro-acoustic response of Solar Arrays during launch
One of the primary elements on the space missions is the electrical power subsystem, for which the critical component is the solar array. The behaviour of these elements during the ascent phase of the launch is critical for avoiding damages on the solar panels, which are the primary source of energy for the satellite in its final configuration. The vibro-acoustic response to the sound pressure depends on the solar array size, mass, stiffness and gap thickness. The stowed configuration of the solar array consists of a multiple system composed of structural elements and the air layers between panels. The effect of the air between panels on the behaviour of the system affects the frequency response of the system not only modifying the natural frequencies of the wings but also as interaction path between the wings of the array. The usual methods to analyze the vibro-acoustic response of structures are the FE and BE methods for the low frequency range and the SEA formulation for the high frequency range. The main issue in the latter method is, on one hand, selecting the appropriate subsystems, and, on the other, identifying the parameters of the energetic system: the internal and coupling loss factors. From the experimental point of view, the subsystems parameters can be identified by exciting each subsystem and measuring the energy of all the subsystems composing the Solar Array. Although theoretically possible, in practice it is difficult to apply loads on the air gaps. To analyse this situation, two different approaches can be studied depending on whether the air gaps between the panels are included explicitly in the problem or not. For a particular case of a solar array of three wings in stowed configuration both modelling philosophies are compared. This stowed configuration of a three wing solar arrays in stowed configuration has been tested in an acoustic chamber. The measured data on the solar wings allows, in general, determining the loss factors of the configuration. The paper presents a test description and measurements on the structure, in terms of the acceleration power spectral density. Finally, the performance of each modelling technique has been evaluated by comparison between simulations with experimental results on a spacecraft solar array and the influence on the apparent properties of the system in terms of the SEA loss factors has been analyse
Energía y productos de hidrólisis a partir de cultivos industriales y forestales
Se caracterizan química y energéticamente diversas especiesvegetales de elevada producción de biomasa (Eucalyptus globulus, tallos de girasol, Chamaecitysus proliferus, Paulownia fortunei, Leucaena diversifolia y Arundo donax) y se estudia el proceso de autohidrólisis en condiciones no isotermas en un marco general de evaluación de la valorización por fraccionamiento y aprovechamiento integral de las fracciones lignocelulósicas con posterior aprovechamiento energético de la fase sólida post-hidrólisis. Los procesos de autohidrólisis se han revelado particularmente interesantes en el caso de las especies madereras estudiadas frente a las especies herbáceas con variaciones en la extracción de la fracción de xilano a 180ºC entre el 19,7% de Eucalyptus globulus y el 36,8% de Leucaenadiversifolia y a 200ºC entre el 57,9% de Paulownia fortunei y el 79,1% de Chamaecytisus proliferus. Las especies madereras de corta rotación de cultivo ensayadas se manifiestan más susceptibles que la especie de referencia (Eucalyptus globulus) al proceso de autohidrólisis a bajas temperaturas. La explotación de las especies madereras de corta rotación ensayadas por combustión directa de la fracción sólida post-autohidrólisis a 200ºC aporta, además de la valorización inherente a los oligómeros y monosacáridos de la fracción líquida, un aumento del poder calorífico relativo de la fracción sólida post-autohidrólisis del 3,4% en Paulownia fortunei y 6,7% en Leucaena diversifolia
Fabrication and Characterization of Multiband Solar Cells Based on Highly Mismatched Alloys
Multiband solar cells are one type of third generation photovoltaic devices in which an increase of the power conversion efficiency is achieved through the absorption of low energy photons while preserving a large band gap that determines the open circuit voltage. The ability to absorb photons from different parts of the solar spectrum originates from the presence of an intermediate energy band located within the band gap of the material. This intermediate band, acting as a stepping stone allows the absorption of low energy photons to transfer electrons from the valence band to the conduction band by a sequential two photons absorption process. It has been demonstrated that highly mismatched alloys offer a potential to be used as a model material system for practical realization of multiband solar cells. Dilute nitride GaAs1-xNx highly mismatched alloy with low mole fraction of N is a prototypical multiband semiconductor with a well-defined intermediate band. Currently, we are using chemical beam epitaxy to synthesize dilute nitride highly mismatched alloys. The materials are characterized by a variety of structural and optical methods to optimize their properties for multiband photovoltaic devices
Aceite de oliva virgen y regulación hormonal de la presión arterial: una revisión del papel de los enzimas proteolíticos
Numerosos estudios realizados en los últimos años, han puesto de manifiesto que los niveles elevados de grasa en la dieta están directamente relacionados con el desarrollo de diversas patologías, entre las que destacan enfermedades cardiovasculares, diabetes o incluso diversos tipos de cánceres. Estudios epidemiológicos también han demostrado que no sólo es importante la cantidad, sino también el tipo de grasa de la dieta. Son especialmente conocidos los efectos beneficiosos de la dieta mediterránea, caracterizada entre otros aspectos, por un consumo elevado de ácidos grasos monoinsaturados como el oleico. En cualquier caso, no se conoce con exactitud las relaciones existentes entre el tipo de grasa de la dieta y el desarrollo de las distintas patologías. Las aminopeptidasas son enzimas proteolíticos implicados en una amplia variedad de procesos biológicos, destacando su papel en el control de la presión arterial a través del sistema renina-angiotensina. En esta revisión se estudia la influencia de una dieta enriquecida en aceite de oliva sobre la actividad aminopeptidásica sérica y de tejidos periféricos, analizando su influencia en la regulación del sistema renina-angiotensina para el control de la presión arterial y el balance de líquidos y electrolitos.The intake of high fat dietary levels is related to the development of several pathologies such as cardiovascular diseases, diabetes and cancer. However, epidemiological studies have demonstrated that not only the amount but also the type of dietary fat participates in the origin of the diseases. In fact, several important beneficts have been attributed to the Mediterranean diet, characterized by the high intake of monoinsaturated fatty acids such as oleic acid preferently. In any case, the relationship between the type of dietary fat an the development of diseases are unknown. Aminopeptidases are proteolytic enzymes involved in several biological proccesses, regulating blood pressure through the renin-angiotensin system. In this review, the influence of an olive oil-enriched diet is presented, analyzing their role in the regulation of blood pressure, local blood flow and fluid and electrolytic balance among other functions
Boundary Treatment for High-Order IMEX Runge–Kutta Local Discontinuous Galerkin Schemes for Multidimensional Nonlinear Parabolic PDEs
It includes supplementary materials[Abstract]: In this article, we propose novel boundary treatment algorithms to avoid order reduction when implicit-explicit Runge–Kutta time discretization is used for solving convection-diffusion-reaction problems with time-dependent Dirichlet boundary conditions. We consider Cartesian meshes and PDEs with stiff terms coming from the diffusive parts of the PDE. The algorithms treat boundary values at the implicit-explicit internal stages in the same way as the interior points. The boundary treatment strategy is designed to work with multidimensional problems with possible nonlinear advection and source terms. The proposed methods recover the designed order of convergence by numerical verification. For the spatial discretization, in this work, we consider local discontinuous Galerkin methods, although the developed boundary treatment algorithms can operate with other discretization schemes in space, such as finite differences, finite elements, or finite volumes.The third author's research has been funded by FEDER and the Spanish Governmentthrough the coordinated research project RTI2018-096064-B-C1, and has been partially funded byMCIN/AEI and "European Union NextGenerationEU/PRTR" through grant PDC2022-133663-C21 and by MCIN/AEI and "ERDF: A Way of Making Europe"" by the European Union through grant PID2022-137637NB-C21. The other authors' research has been funded by grant ED431G 2023/01 of CITIC, funded by Consellería de Educación, Universidade e Formación Profesional of Xunta deGalicia and FEDER, and by Spanish MINECO under research project number PID2019-10858RB-I00Xunta de Galicia; ED431G 2023/0
El uso del portafolio para la enseñanza en Enfermería. Experiencia de tres cursos académicos
El Espacio Europeo de Educación Superior (EEES) parece configurarse como un diseño de cambio estratégico para crear un espacio común de reconocimiento de la enseñanza-aprendizaje que profesores y alumnos realizan para dar respuestas profesionales a las demandas y necesidades sociales. Así, surgen nuevas propuestas y numerosos escenarios para reflexionar sobre esa tarea y numerosas oportunidades para la innovación pedagógica. Consecuentemente diseñamos un plan de innovación educativa experimental que hemos desarrollado con alumnos de Enfermería durante los tres últimos cursos académicos
Early imaging and molecular changes with neoadjuvant bevacizumab in stage ii/iii breast cancer
This prospective, phase II study evaluated novel biomarkers as predictors of response to bevacizumab in patients with breast cancer (BC), using serial imaging methods and gene expression analysis. Patients with primary stage II/III BC received bevacizumab 15 mg/kg (cycle 1; C1), then four cycles of neoadjuvant docetaxel doxorubicin, and bevacizumab every 3 weeks (C2–C5). Tumour proliferation and hypoxic status were evaluated using18F-fluoro-3'-deoxy-3'-L-fluorothymidine (FLT)-and18F-fluoromisonidazole (FMISO)-positron emission tomography (PET) at baseline, and during C1 and C5. Pre-and post-bevacizumab vascular changes were evaluated using dynamic contrastenhanced magnetic resonance imaging (DCE-MRI). Molecular biomarkers were assessed using microarray analysis. A total of 70 patients were assessed for treatment efficacy. Significant decreases from baseline in tumour proliferation (FLT-PET), vascularity, and perfusion (DCE-MRI) were observed during C1 (p = 0.001), independent of tumour subtype. Bevacizumab treatment did not affect hypoxic tumour status (FMISO-PET). Significant changes in the expression of 28 genes were observed after C1. Changes in vascular endothelial growth factor receptor (VEGFR)-2p levels were observed in 65 patients, with a > 20% decrease in VEGFR-2p observed in 13/65. Serial imaging techniques. © 2021 by the authors. Licensee MDPI, Basel, Switzerland
Geochemical characterization of the mining district of Linares (Jaen, Spain) by means of XRF and ICP-AES
Linares (Jaen, Spain) has been subjected to an intense mining and metallurgic activity during 2500 years. Basically, lead and silver have been extracted from galena; as well as copper and zinc. Different studies have been conducted to evaluate trace element concentrations to obtain relationships with anthropogenic and geologic factors. The analytical results of these studies have been obtained with ICP-AES. This analytical technique is relatively expensive and inaccessible in zones with scarce economic means. In this study, XRF analyses have been conducted and the obtained results are presented, as well as a comparison with the previously obtained ICP results. In both cases, a cluster analysis has been made to try to identify the same relations in the target area. 5 groups have been identified, mainly related with lithology. Only 10 of the 122 grid squares (each one of 1 km2) are classified in different groups if the cluster analysis is conducted with XRF results or ICP results. ICP classifies better where these grid squares are located, mostly, in contact zones of different lithologies
Preliminary data on the ovarian histological structures observed in black hakes (M. polli and M. senegalensis) off Mauritania
The black hakes, Merluccius polli and M. senegalensis, are target species of a trawl Spanish fleet in Mauritanian waters. M. polli is a deep-water hake while M. senegalensis shows a shallower distribution. Both species are mixed in the landings, although the deeper hake totals a greater fraction (85%) of the catch due to the fishing strategy of the trawl fleet.
The female gonads of both hakes were collected during an experimental survey carried out in the Mauritanian EEZ. Mature ovaries were examined from the start of the reproductive season in this area. Ovaries were processed by a standard histological technique. Histological characteristics of ovarian tissues and oocyte stages were studied by light microscopy. The ovaries of black hakes showed various stages of oocyte development from the small sized, chromatin nuclear and perinucleolar oocytes, and the medium sized, cortical alveoli and vitellogenic oocytes. This last stage presents yolk granules occupying the cytoplasm at different levels. In the case of M. senegalensis, the presence of large sized oocytes with early migration of the nucleus to the animal pole, as well as fusion of oil droplets indicate maturation and imminent spawning, thus, indicating an earlier spawning than M. polli. Furthermore, postovulatory follicles observed in M. senegalensis indicate a recent batch spawning episode. This result is concordant with the values of GSI obtained for both species in these waters. The reproductive period extends from October to Mars with a defined peak in December - January for females of both hakes, although the shallower species, M. senegalensis, shows an earlier spawning in this study. Atretic stages were observed, but their incidence was low because the sampling corresponds to the beginning of the spawning period. The species are multiple batch spawners as suggested by their oocyte size frequency distribution in the ovary. The present study is a first approach to ovarian histology of M. polli and M. senegalensis, and intended to provide basic knowledge for further detailed studies on the reproductive biology of these species, essential for an adequate assessment of this stock.Instituto Español de Oceanografía (IEO
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