137 research outputs found

    SOFTWARE PARA LA PROGRAMACIÓN DE UN RIEGO DE PRECISIÓN EN EL CULTIVO DE LA FRESA

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    [ES] Bajo un escenario de menor disponibilidad de agua, aumento de la frecuencia de las sequías y las incertidumbres asociadas al cambio climático, el sector del riego en Europa tiene que aumentar la productividad del agua mediante una mejora de la eficiencia en el uso de la misma. El sector fresero concentrado en un entorno de alta sensibilidad medioambiental (Parque Nacional de Doñana, Huelva, España) es un buen ejemplo de cultivo con alta dependencia de recursos hídricos. Más del 90% de la producción es destinada a mercados internacionales que demandan fresas de alta calidad, producidas en condiciones sostenibles. Por tanto, para asegurar la supervivencia del cultivo de fresa en la zona de Huelva resulta imprescindible desarrollar herramientas que permitan a los productores un uso óptimo de estos recursos hídricos. Por ello, el objetivo de este trabajo fue desarrollar un software (Irri-Fresa) que permita a los productores de fresa en la zona de Huelva realizar una programación de riego que maximice la eficiencia en el uso de los recursos hídricos, teniendo en cuenta la configuración hidráulica de cada sector de riego así como las condiciones climáticas en tiempo real de la zona y el estado fenológico del cultivo. Irri-Fresa proporciona al sector del cultivo de la fresa una herramienta fácil y rápida para obtener una programación de riego óptima y actualizada por semanas y personalizada por cada usuario. Este software, actualmente, está siendo usado satisfactoriamente por diversos productores de la zona, obteniendo ahorros significativos de agua, ayudando a concienciar al sector fresero de la importancia de conocer y optimizar sus consumos de agua.González Perea, ,R.; Fernández García, I.; Martin Arroyo, M.; Rodríguez Díaz, J.; Camacho Poyato, E.; Montesinos, P. (2015). SOFTWARE PARA LA PROGRAMACIÓN DE UN RIEGO DE PRECISIÓN EN EL CULTIVO DE LA FRESA. En XXXIII CONGRESO NACIONAL DE RIEGOS. Valencia 16-18 junio de 2015. Editorial Universitat Politècnica de València. https://doi.org/10.4995/CNRiegos.2015.1452OC

    EL RIEGO DE PRECISIÓN EN EL CULTIVO DE FRESA EN LA PROVINCIA DE HUELVA

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    [ES] El cultivo de fresa es el cultivo con mayor repercusión económica y social de la provincia de Huelva, ya que España es el principal productor de fresa fresca de Europa y el segundo del mundo, situándose el 95% de esa producción en la provincia de Huelva. Sin embargo, la zona donde se desarrolla el cultivo, el entorno del Parque Nacional de Doñana, es una de las zonas de mayor sensibilidad ambiental de Europa y cualquier actividad que se desarrolle debe evitar impactos negativos en el mismo. De lo anterior se deduce la necesidad de buscar un equilibrio para que agricultura y medio ambiente puedan convivir en el entorno de Doñana. Este trabajo se centra precisamente en eso, en optimizar el uso del agua en la zona mediante la implantación del riego de precisión en el cultivo de fresa, que consiste en dar a la planta el agua que necesita en el momento adecuado. La implantación de un sistema de riego de precisión se ha llevado a cabo en la campaña 2013/2014 en una finca comercial de la zona Almonte-El Rocío, provincia de Huelva. Para ello se ha implantado un ensayo en 5 sectores distintos, cada uno con un tipo de emisor diferente, en el que se realizó una programación óptima del riego basada en el cálculo de las necesidades teóricas del cultivo, el análisis hidráulico del sector y el movimiento del agua en el suelo, y cuyo comportamiento se comparó con un sector testigo manejado por el agricultor. Estas técnicas permitieron ahorrar un 43% de agua, en las condiciones particulares de suelo, variedad y configuración de la red riego de la finca de ensayo, obteniéndose un ligero aumento de producción respecto al manejo tradicional del agricultor, lo que se tradujo en un incremento de la rentabilidad del cultivo y de una mejora de la sostenibilidad en la producción intensiva de fresas.Martín Arroyo, M.; Fernandez García, I.; Gonzalez Perea, R.; García Morillo, J.; Rodríguez Díaz, J.; Camacho Poyato, E.; Montesinos Barrios, P. (2015). EL RIEGO DE PRECISIÓN EN EL CULTIVO DE FRESA EN LA PROVINCIA DE HUELVA. En XXXIII CONGRESO NACIONAL DE RIEGOS. Valencia 16-18 junio de 2015. Editorial Universitat Politècnica de València. https://doi.org/10.4995/CNRiegos.2015.1462OC

    Cortical thinning over two years after first-episode psychosis depends on age of onset

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    First-episode psychosis (FEP) patients show structural brain abnormalities at the first episode. Whether the cortical changes that follow a FEP are progressive and whether age at onset modulates these changes remains unclear. This is a multicenter MRI study in a deeply phenotyped sample of 74 FEP patients with a wide age range at onset (15-35 years) and 64 neurotypical healthy controls (HC). All participants underwent two MRI scans with a 2-year follow-up interval. We computed the longitudinal percentage of change (PC) for cortical thickness (CT), surface area (CSA) and volume (CV) for frontal, temporal, parietal and occipital lobes. We used general linear models to assess group differences in PC as a function of age at FEP. We conducted post-hoc analyses for metrics where PC differed as a function of age at onset. We found a significant age-by-diagnosis interaction effect for PC of temporal lobe CT (d = 0.54; p = 002). In a post-hoc-analysis, adolescent-onset (≤19 y) FEP showed more severe longitudinal cortical thinning in the temporal lobe than adolescent HC. We did not find this difference in adult-onset FEP compared to adult HC. Our study suggests that, in individuals with psychosis, CT changes that follow the FEP are dependent on the age at first episode, with those with an earlier onset showing more pronounced cortical thinning in the temporal lobe

    The effect of family environment and psychiatric family history on psychosocial functioning in first-episode psychosis at baseline and after 2 years

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    Abstract The aim of the present study was to evaluate the contribution of family environment styles and psychiatric family history on functioning of patients presenting first-episode psychosis (FEP). Patients with FEP and healthy controls (HC) were assessed at baseline and after 2 years. The Functional Assessment Short Test (FAST) was used to assess functional outcome and the Family Environment Scale (FES) to evaluate family environment. Linear regressions evaluated the effect that family environment exerts on functioning at baseline and at 2-year follow-up, when FEP patients were diagnosed according to non-affective (NA-PSYCH) or affective psychoses (APSYCH). The influence of a positive parents' psychiatric history on functioning was evaluated through one-way between-groups analysis of covariance (ANCOVA) models, after controlling for family environmental styles. At baseline, FEP patients presented moderate functioning impairment, significantly worse than HC (28.65±16.17 versus 3.25±7.92; p<0.001, g = 1.91). At 2-year follow-up, the functioning of NA-PSYCH patients was significantly worse than in A-PSYCH (19.92±14.83 versus 12.46±14.86; p = 0.020, g = 0.50). No specific family environment style was associated with functioning in FEP patients and HC. On the contrary, a positive psychiatric father's history influenced functioning of FEP patients. After 2 years, worse functioning in NA-PSYCH patients was associated with lower rates of active-recreational and achievement orientated family environment and with higher rates of moral-religious emphasis and control. In A-PSYCH, worse functioning was associated with higher rates of conflict in the family. Both family environment and psychiatric history influence psychosocial functioning, with important implications for early interventions, that should involve both patients and caregivers

    Cognitive clusters in first-episode psychosis

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    Impairments in a broad range of cognitive domains have been consistently reported in some individuals with first-episode psychosis (FEP). Cognitive deficits can be observed during the prodromal stage. However, the course of cognitive deficits is still unclear. The aim of this study was to identify cognitive subgroups over time and to compare their sociodemographic, clinical and functional profiles. A total of 114 patients with Schizophrenia Spectrum Disorders were included in the present study. We assessed subjects through psychiatric scales and eight neuropsychological tests at baseline and at two-year follow-up visit. We performed the Partition Around Medoids algorithm with all cognitive variables. Furthermore, we performed a logistic regression to identify the predictors related to the different cognitive clusters at follow-up. Two distinct subgroups were found: the first cluster characterized by cognitive impairment and a second cluster had relatively intact cognition in comparison with norms. Up to 54.7% of patients with cognitive deficits at baseline tended to improve during the first two years of treatment. Patients with intact cognition at follow-up had a higher socioeconomic status, later age of onset, lower negative symptoms and a higher cognitive reserve (CR) at baseline. CR and age of onset were the baseline variables that predicted cognitive impairment. This research allows us to obtain a better understanding of the heterogeneous profile of psychotic disorders. Identifying the characteristics of patients who wil

    Association of IGF1 and KDM5A polymorphisms with performance, fatness and carcass traits in chickens

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    Two functional and positional candidate genes were selected in a region of chicken chromosome 1 (GGA1), based on their biological roles, and also where several quantitative trait loci (QTL) have been mapped and associated with performance, fatness and carcass traits in chickens. The insulin-like growth factor 1 (IGF1) gene has been associated with several physiological functions related to growth. The lysine (K)-specific demethylase 5A (KDM5A) gene participates in the epigenetic regulation of genes involved with the cell cycle. Our objective was to find associations of selected single-nucleotide polymorphisms (SNPs) in these genes with performance, fatness and carcass traits in 165 F chickens from a resource population. In the IGF1 gene, 17 SNPs were detected, and in the KDM5A gene, nine SNPs were detected. IGF1 SNP c. 47673G > A was associated with body weight and haematocrit percentage, and also with feed intake and percentages of abdominal fat and gizzard genotype × sex interactions. KDM5A SNP c. 34208C > T genotype × sex interaction affected body weight, feed intake, percentages of abdominal fat (p = 0. 0001), carcass, gizzard and haematocrit. A strong association of the diplotype × sex interaction (p < 0. 0001) with abdominal fat was observed, and also associations with body weight, feed intake, percentages of carcass, drums and thighs, gizzard and haematocrit. Our findings suggest that the KDM5A gene might play an important role in the abdominal fat deposition in chickens. The IGF1 and KDM5A genes are strong candidates to explain the QTL mapped in this region of GGA1

    Measurement of the Crab Nebula Spectrum Past 100 TeV with HAWC

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    We present TeV gamma-ray observations of the Crab Nebula, the standard reference source in ground-based gamma-ray astronomy, using data from the High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory. In this analysis we use two independent energy-estimation methods that utilize extensive air shower variables such as the core position, shower angle, and shower lateral energy distribution. In contrast, the previously published HAWC energy spectrum roughly estimated the shower energy with only the number of photomultipliers triggered. This new methodology yields a much improved energy resolution over the previous analysis and extends HAWC's ability to accurately measure gamma-ray energies well beyond 100 TeV. The energy spectrum of the Crab Nebula is well fit to a log parabola shape (dNdE=ϕ0(E/7 TeV)αβln(E/7 TeV))\left(\frac{dN}{dE} = \phi_0 \left(E/\textrm{7 TeV}\right)^{-\alpha-\beta\ln\left(E/\textrm{7 TeV}\right)}\right) with emission up to at least 100 TeV. For the first estimator, a ground parameter that utilizes fits to the lateral distribution function to measure the charge density 40 meters from the shower axis, the best-fit values are ϕo\phi_o=(2.35±\pm0.040.21+0.20^{+0.20}_{-0.21})×\times1013^{-13} (TeV cm2^2 s)1^{-1}, α\alpha=2.79±\pm0.020.03+0.01^{+0.01}_{-0.03}, and β\beta=0.10±\pm0.010.03+0.01^{+0.01}_{-0.03}. For the second estimator, a neural network which uses the charge distribution in annuli around the core and other variables, these values are ϕo\phi_o=(2.31±\pm0.020.17+0.32^{+0.32}_{-0.17})×\times1013^{-13} (TeV cm2^2 s)1^{-1}, α\alpha=2.73±\pm0.020.02+0.03^{+0.03}_{-0.02}, and β\beta=0.06±\pm0.01±\pm0.02. The first set of uncertainties are statistical; the second set are systematic. Both methods yield compatible results. These measurements are the highest-energy observation of a gamma-ray source to date.Comment: published in Ap

    Seasonal drought limits tree species across the Neotropics

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    Within the tropics, the species richness of tree communities is strongly and positively associated with precipitation. Previous research has suggested that this macroecological pattern is driven by the negative effect of water-stress on the physiological processes of most tree species. This process implies that the range limits of taxa are defined by their ability to occur under dry conditions, and thus in terms of species distributions it predicts a nested pattern of taxa distribution from wet to dry areas. However, this ‘dry-tolerance’ hypothesis has yet to be adequately tested at large spatial and taxonomic scales. Here, using a dataset of 531 inventory plots of closed canopy forest distributed across the Western Neotropics we investigated how precipitation, evaluated both as mean annual precipitation and as the maximum climatological water deficit, influences the distribution of tropical tree species, genera and families. We find that the distributions of tree taxa are indeed nested along precipitation gradients in the western Neotropics. Taxa tolerant to seasonal drought are disproportionally widespread across the precipitation gradient, with most reaching even the wettest climates sampled; however, most taxa analysed are restricted to wet areas. Our results suggest that the ‘dry tolerance’ hypothesis has broad applicability in the world's most species-rich forests. In addition, the large number of species restricted to wetter conditions strongly indicates that an increased frequency of drought could severely threaten biodiversity in this region. Overall, this study establishes a baseline for exploring how tropical forest tree composition may change in response to current and future environmental changes in this region

    Carbon uptake by mature Amazon forests has mitigated Amazon nations' carbon emissions

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    Background: Several independent lines of evidence suggest that Amazon forests have provided a significant carbon sink service, and also that the Amazon carbon sink in intact, mature forests may now be threatened as a result of different processes. There has however been no work done to quantify non-land-use-change forest carbon fluxes on a national basis within Amazonia, or to place these national fluxes and their possible changes in the context of the major anthropogenic carbon fluxes in the region. Here we present a first attempt to interpret results from groundbased monitoring of mature forest carbon fluxes in a biogeographically, politically, and temporally differentiated way. Specifically, using results from a large long-term network of forest plots, we estimate the Amazon biomass carbon balance over the last three decades for the different regions and nine nations of Amazonia, and evaluate the magnitude and trajectory of these differentiated balances in relation to major national anthropogenic carbon emissions. Results: The sink of carbon into mature forests has been remarkably geographically ubiquitous across Amazonia, being substantial and persistent in each of the five biogeographic regions within Amazonia. Between 1980 and 2010, it has more than mitigated the fossil fuel emissions of every single national economy, except that of Venezuela. For most nations (Bolivia, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname) the sink has probably additionally mitigated all anthropogenic carbon emissions due to Amazon deforestation and other land use change. While the sink has weakened in some regions since 2000, our analysis suggests that Amazon nations which are able to conserve large areas of natural and semi-natural landscape still contribute globally-significant carbon sequestration. Conclusions: Mature forests across all of Amazonia have contributed significantly to mitigating climate change for decades. Yet Amazon nations have not directly benefited from providing this global scale ecosystem service. We suggest that better monitoring and reporting of the carbon fluxes within mature forests, and understanding the drivers of changes in their balance, must become national, as well as international, priorities
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