1,576 research outputs found

    Ain expected impacts and adaptation activities proposed in front of the global change for the North- Central Chubut, Patagonia Argentina

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    La provincia del Chubut (Patagonia Argentina) posee una riqueza florística importante debido a la presencia de muchos endemismos entre las especies nativas. La biodiversidad vegetal incrementa la eficiencia de uso de los recursos y contribuye a estabilizar el funcionamiento de los ecosistemas frente a factores que los perturben. Los ecosistemas de las zonas áridas se diferencian por su débil capacidad para restablecerse y más de una vez, se torna difícil revertir la degradación a la que son sometidos, por ello reviste importancia tener conocimiento sobre la dinámica y la diversidad florística. En gran parte de la provincia del Chubut se produjo un agravamiento de las condiciones ambientales debido a las sequías iniciadas entre los años 2006 y 2008 y que se prolongaron por 5 a 7 años. Además las erupciones volcánicas ocurridas en 2008 (Volcán Chaitén) y 2011 (Volcán Puyehue) que cubrieron el terreno de cenizas, afectaron la disponibilidad de forraje. Los departamentos del centro-norte de la provincia (Telsen, Gastre, Paso de Indios y Mártires), en estos últimos diez años, fueron los más afectados y sufrieron la mayor pérdida en número de cabezas de ganado. Luego de más de 20 años de recorrer la estepa patagónica, con numerosas campañas de exploración botánica (más de 70) y observando diversos ambientes en diferentes estados de condición con diferentes problemas de degradación, cargas animales y condiciones ambientales (sitios con relevamientos de más de diez años), hemos llegado a percibir los principales impactos esperados del cambio climático global, en los departamentos del centro-norte de Chubut. Por último, se proponen actividades de adaptación frente al impacto del cambio climáticoThe Chubut province (Patagonia Argentina) has an important floristic richness due to the presence of many endemisms among the native species. Plant biodiversity increases the efficiency of resource use and helps to stabilize the functioning of ecosystems against factors that disturb them. The ecosystems of arid zones are differentiated by their weak capacity to re-establish themselves and more than once, it becomes difficult to reverse the degradation to which they are subjected, so it is important to have know ledge about floristic dynamics and diversity. In much of the Chubut province there was an aggravation of environmental conditions due to droughts started between 2006 and 2008 and that lasted for 5 to 7 years. In addition volcanic eruptions occurred in 2008 (Chaitén Volcano) and 2011 (Puyehue Volcano) that covered the ash ground, affected the availability of forage. The departments of the center-north of the province (Telsen, Gastre, Paso de Indios and Mártires), in these last ten years, were the most affected and suffered the greatest loss in number of head of cattle. After numerous field trips during more than 20 years in Patagonian steppe, with numerous botanical exploration campaigns (more than 70) and observing different environments in different condition states, with different problems of degradation, animal loads and environmental conditions (sites with more than ten years of flora censuses), we have come to perceive the main expected impacts of global climate change, in the central-northern departments of Chubut. Finally, adaptation activities are proposed against the impact of climate change.Fil: González Cinthya C.. Universidad Nacional de la Patagonia "san Juan Bosco". Facultad de Cs.naturales - Sede Trelew. Departamento de Biología; ArgentinaFil: Llorens, Magdalena. Universidad Nacional de la Patagonia "san Juan Bosco". Facultad de Cs.naturales - Sede Trelew. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Calderón, Daniela Anabel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia "san Juan Bosco". Facultad de Cs.naturales - Sede Trelew. Departamento de Biología; Argentin

    Erratum to : Effect of a mixed reality-based intervention on arm, hand, and finger function on chronic stroke

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    Altres ajuts: This study was funded in part by the Project TEREHA (IDI-20110844) and Project NeuroVR (TIN2013-44741-R) of the Ministerio de Economía y Competitividad of Spain, the Project Consolider-C (SEJ2006-14301/PSIC) of the Ministerio de Educación y Ciencia of Spain, the "CIBER of Physiopathology of Obesity and Nutrition, an initiative of ISCIII", and the Excellence Research Program PROMETEO of the Conselleria de Educación of Generalitat Valenciana (2008-157)Erratum: The original article mistakenly omitted a key affiliation for the author, Carolina Colomer. The authors would therefore like to state the affiliation of 'Universidad Autónoma de Barcelona, Barcelona, Spain' as the second affiliation for Dr Colomer.Furthermore, the authors would also like to add a statement to the Acknowledgements sub-section stating: "This work has been developed within the framework of a medical doctorate at the Universidad Autónoma de Barcelona.

    Sap flow of a wild cherry tree plantation growing under Mediterranean conditions: Assessing the role of environmental conditions on canopy conductance and the effect of branch pruning on water productivity

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    In recent decades, wild cherry has been one of the species most widely used for reforestation in Europe. Studies aiming to select and improve trees to give them the best growth rates and wood properties have increased in response to growers’ demands. However, information relating to key physiological processes such as transpiration or stomatal conductance and to the effect of the common practice of pruning on plant–water relations is scarce. The main objective of this study was to assess the effects of environmental conditions on canopy conductance dynamics. Its secondary objective was to examine the short- and medium-term effects of branch pruning on tree transpiration, growth and derived water productivity. To this end, we measured sap flow in an experimental plantation where trees were subjected to drip irrigation and rain-fed conditions and where variables characterizing climate, soil and tree growth were also monitored. The results demonstrated that the Jarvis–Stewart approach was appropriate for studying the responses of canopy conductance to environmental factors. As well as the role of vapour pressure deficit and net radiation in controlling the daily variations of canopy conductance, the single effects of decreasing soil water content (optimum relative extractable water, REW, higher than 0.4) and increasing air temperature (optimum of 21 °C), as summer conditions approached, were correctly incorporated into the modelling exercise. Soil water content exerted the greatest control on canopy conductance for trees growing under rain-fed conditions, while air temperature did for irrigated trees. Pruning significantly reduced transpiration to about 35% when pre- and post-sub-periods were compared, but also affected annual water productivity regardless of the irrigation treatment. To assess the long-term effects of pruning on water productivity, measurements in both pruned and unpruned trees would be desirable.info:eu-repo/semantics/acceptedVersio

    The Gypsy Database (GyDB) of mobile genetic elements: release 2.0

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    This article introduces the second release of the Gypsy Database of Mobile Genetic Elements (GyDB 2.0): a research project devoted to the evolutionary dynamics of viruses and transposable elements based on their phylogenetic classification (per lineage and protein domain). The Gypsy Database (GyDB) is a long-term project that is continuously progressing, and that owing to the high molecular diversity of mobile elements requires to be completed in several stages. GyDB 2.0 has been powered with a wiki to allow other researchers participate in the project. The current database stage and scope are long terminal repeats (LTR) retroelements and relatives. GyDB 2.0 is an update based on the analysis of Ty3/Gypsy, Retroviridae, Ty1/Copia and Bel/Pao LTR retroelements and the Caulimoviridae pararetroviruses of plants. Among other features, in terms of the aforementioned topics, this update adds: (i) a variety of descriptions and reviews distributed in multiple web pages; (ii) protein-based phylogenies, where phylogenetic levels are assigned to distinct classified elements; (iii) a collection of multiple alignments, lineage-specific hidden Markov models and consensus sequences, called GyDB collection; (iv) updated RefSeq databases and BLAST and HMM servers to facilitate sequence characterization of new LTR retroelement and caulimovirus queries; and (v) a bibliographic server. GyDB 2.0 is available at http://gydb.org

    Engineering the reciprocal space for ultrathin GaAs solar cells

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    III-V solar cells dominate the high efficiency charts, but with significantly higher cost than other solar cells. Ultrathin III-V solar cells can exhibit lower production costs and immunity to short carrier diffusion lengths caused by radiation damage, dislocations, or native defects. Nevertheless, solving the incomplete optical absorption of sub-micron layers presents a challenge for light-trapping structures. Simple photonic crystals have high diffractive efficiencies, which are excellent for narrow-band applications. Random structures a broadband response instead but suffer from low diffraction efficiencies. Quasirandom (hyperuniform) structures lie in between providing high diffractive efficiency over a target wavelength range, broader than simple photonic crystals, but narrower than a random structure. In this work, we present a design method to evolve a simple photonic crystal into a quasirandom structure by modifying the spatial-Fourier space in a controlled manner. We apply these structures to an ultrathin GaAs solar cell of only 100 nm. We predict a photocurrent for the tested quasirandom structure of 25.3 mA/cm2^2, while a planar structure would be limited to 16.1 mA/cm2^2. The modified spatial-Fourier space in the quasirandom structure increases the amount of resonances, with a progression from discrete number of peaks to a continuum in the absorption. The enhancement in photocurrent is stable under angle variations because of this continuum. We also explore the robustness against changes in the real-space distribution of the quasirandom structures using different numerical seeds, simulating variations in a self-assembly method

    Effect of irrigation on sap flux density variability and water use estimate in cherry (Prunus avium) for timber production: Azimuthal profile, radial profile and sapwood estimation

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    9 páginas.-- 7 figuras.-- 3 tablas.-- 30 referenciasInformation on tree water use in plantations for high quality wood is scarce, thus studies are needed toproperly estimate the irrigation demand of these plantations. Plant water use estimation with sap flowsensors has been used extensively. However, biases in tree sap flow estimate can arise from variationson radial and azimuthal profiles of sap flux density and also from the sapwood area considered for theup-scaling from sap flux density to sap flux. This work aimed to (1) study the spatial variations of sapflux density in cherry trees in a timber orientated plantation, (2) compare several methods to estimatesapwood depth in cherry trees and (3) to evaluate the effect of drip irrigation on these factors. The resultsshowed that most of the studied trees had decreasing radial sap flux density profiles with depth asexpected. However, the three irrigated trees of bigger sizes still showed high sap flux densities in theirinner tissues, at contrast with the rest of the trees and especially with the non irrigated ones of similarsize with values close to 20% of the sap flux density measured at 1 cm depth from cambium. On the otherhand, the different methods tested to estimate sapwood depth gave significantly different results andonly the two methods of visual identification in wood cores based on color change and measurementsof sap flux densities along the xylem radius may be considered suitable for scaling purposes. Moreover,azimuthal variation pattern was found to be random in all the studied trees, and the ranking between theaspects (north, south, east and west) was not affected by either drip irrigation or sun exposition, and thusmeasuring sap flux density in any particular aspect has been shown to be suitable to estimate the overalltree sap flux. We conclude that more studies are necessary to properly assess the radial profile of sapflux density, especially when considering the high sap flux density in the inner tissues of the three biggerirrigated trees as compared to the other trees, and also how this pattern seemed to indicate sapwooddepths values very contrasted to the ones estimated from color change in wood cores.Acknowledgments MONTES (CSD 2008-00040) projectsfunded by the Spanish Ministry of Science and Innovation. The firstauthor was the recipient of a FPI grant from the Spanish Ministryof Economy and Competitiveness. The field work of Eulalia Serra,Beatriz Grau, Marc Ferrer and Cristian Morales is highly appreci-ated.Peer reviewe

    Valorization of Ferulic Acid from Agro-Industrial by-Products for Application in Agriculture

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    The use of bioplastic mulch in agriculture has increased dramatically in the last years throughout the world. Nowadays, biodegradable materials for mulching films strive to constitute a reliable and more sustainable alternative to classical materials such as polyethylene (PE). The main challenge is to improve their durability in the soil to meet the required service length for crop farming by using benign and sustainable antioxidant systems. Here, we report the design and fabrication of biodegradable materials based on polybutylene (succinate adipate) (PBSA) for mulching applications, incorporating a fully biobased polymeric antioxidant deriving from ferulic acid, which can be extracted from an industrial by-product. Poly-dihydro (ethylene ferulate) (PHEF) from ferulic acid was synthesized by a two-step polymerization process. It is characterized by improved thermal stability in comparison with ferulic acid monomer and therefore suitable for common industrial processing conditions. Different blends of PBSA and PHEF obtained by melt mixing or by reactive extrusion were prepared and analyzed to understand the effect of the presence of PHEF. The results demonstrate that PHEF, when processed by reactive extrusion, presents a remarkable antioxidant effect, even in comparison with commercial additives, preserving a high level of the mechanical properties of the PBSA matrix without affecting the biodegradable character of the blend

    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
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