El bambú (Guadua angustifolia spp.) como alternativa de conducción para un sistema de riego por multicompuertas

The present investigation aimed to use bamboo as a pipeline for a multi floodgates irrigation system in areas where this plant species abounds. Hydraulically characteristics, such as the roughness, speed, its maximum working pressure were determined in the laboratory and field; likewise, a guide was prepared for the selection of the bamboo’s diameters under the conditions of slope and pressure load. The rugosity study of the material was carried out by the Colebrook - White equation, obtaining an absolute rugosity of 0,0161 meters, the Hazen - Williams roughness coefficient getting 50 and the Manning’s roughness coefficient of 0,0232. The study also compared the results of load loss estimated by the three methods, versus the values obtained in the laboratory and statistical indicators (the mean square error and the coefficient of efficiency), these indicators did not present significant differences. Also, that from speeds higher than 0,8 ms -1 , the behavior of the load loss potentially increases and it was found that the bamboo supports pressures up to 30 PSI or 20 mwc.La presente investigación tuvo como objetivo el uso del bambú como tubería de conducción para un sistema de riego por multicompuertas en zonas donde abunda esta especie vegetal. Se analizaron las características hidráulicas como la rugosidad, velocidad y la máxima presión de trabajo en el laboratorio y campo; asimismo, se elaboró una guía para la selección de diámetros en condición de pendiente y carga de presión. El estudio de la rugosidad del material se obtuvo mediante la ecuación de Colebrook-White, una rugosidad absoluta de 0,0161 m, el coeficiente de rugosidad de Hazen-Williams de 50 y el coeficiente de rugosidad de Manning de 0,0232. Se comparó los resultados de las pérdidas de carga estimadas por los tres métodos versus los valores obtenidos en el laboratorio y mediante indicadores estadísticos (error cuadrático medio y coeficiente de eficiencia), estos indicadores no presentaron diferencias significativas. También, a partir de velocidades superiores a 0,8 ms-1, el comportamiento de la pérdida de carga aumenta potencialmente y se encontró que el bambú soporta presiones de hasta 30 PSI o 20 mca

A validation of the boundary element method for grounding grid design and computation

[Abstract] Several widespread intuitive techniques developed during the last two decades for substation grounding analysis, such as the Average Potential Method (APM), have been recently identified as particular cases of a more general Boundary Element formulation [1]. In this approach, problems encountered with the application of these methods [3] can be explained from a mathematically rigorous point of view, and innovative advanced and more eficient techniques can be derived [2]. Numerical results obtained with low and medium levels of discretization (equivalent resistance and leakage current density) seem to be reasonable. However, these solutions still have not been validated. Unrealistic results are obtained when domain discretization is increased, since no one procedure is yet available to eliminate the above mentioned problems. Hence, numerical convergence analyses are precluded. The obtention of highly accurate numerical results by means of standard techniques (FEM, Finite Differences) implies unapproachable computing requirements in practical cases. On the other side, neither practical error estimates have been derived, nor analytical solutions are known for practical cases, nor suficiently accurate experimental measurements have been reported up to this point. In this paper, we present a validation of the results obtained by the Boundary Element proposed formulation, including the classical methods. A highly accurate solution to a specially designed test problem is obtained by means of a 2D FEM model, using up to 80; 000 degrees of freedom. Results are compared with those carried out by Boundary Elements

Measurement of the Z(→ ℓ + ℓ −)γ production cross-section in pp collisions at √s = 13 TeV with the ATLAS detector

The production of a prompt photon in association with a Z boson is studied in proton-proton collisions at a centre-of-mass energy s = 13 TeV. The analysis uses a data sample with an integrated luminosity of 139 fb−1 collected by the ATLAS detector at the LHC from 2015 to 2018. The production cross-section for the process pp → ℓ+ℓ−γ + X (ℓ = e, μ) is measured within a fiducial phase-space region defined by kinematic requirements on the photon and the leptons, and by isolation requirements on the photon. An experimental precision of 2.9% is achieved for the fiducial cross-section. Differential cross-sections are measured as a function of each of six kinematic variables characterising the ℓ+ℓ−γ system. The data are compared with theoretical predictions based on next-to-leading-order and next-to-next-to-leading-order perturbative QCD calculations. The impact of next-to-leading-order electroweak corrections is also considered. [Figure not available: see fulltext.]

Associations between competitive anxiety, athlete characteristics and sport context: evidence from a systematic review and meta-analysis

Background: There is a vast literature investigating the possible associations between competitive anxiety, athlete variables and sports context. As far as we are concerned, there is no study which has compiled such findings to produce more robust evidence on this topic. Objectives: The aim of the study was to conduct an exploratory systematic review of the literature followed by a meta-analysis in order to investigate possible associations between competitive anxiety, socialdemographic characteristics, profile of the athlete and sports context. Methods: Systematic searches of PubMed, PsycInfo, Web of Science, Lilacs and SciELO electronic databases were performed to identify studies published between January 2006 and January 2018, including a manual search in the references of the selected studies. Results: A total of 59 studies were included for qualitative synthesis and 27 for meta-analysis. More robust associations were observed between competitive anxiety and female gender, lower age, and less experience time. Discussion: Knowing the variables which exert influence on competitive anxiety can be relevant to plan specific treatment and intervention programs, enabling the athlete´s development beyond technical and physical preparation

The top right coupling in the aligned two-Higgs-doublet model

We compute the right top quark coupling in the aligned two-Higgs-doublet model. In the Standard Model the real part of this coupling is dominated by QCD-gluon-exchange diagram, but the imaginary part, instead, is purely electroweak at one loop. Within this model we show that values for the imaginary part of the coupling up to one order of magnitude larger than the electroweak prediction can be obtained. For the real part of the electroweak contribution we find that it can be up to three orders of magnitude larger than the standard model one. We also present detailed results of the one loop analytical computation

Traditional agroecosystems as conservatories and incubators of cultivated plant varietal diversity: the case of fig (Ficus carica L.) in Morocco

<p>Abstract</p> <p>Background</p> <p>Traditional agroecosystems are known to host both large crop species diversity and high within crop genetic diversity. In a context of global change, this diversity may be needed to feed the world. Are these agroecosystems museums (i.e. large core collections) or cradles of diversity? We investigated this question for a clonally propagated plant, fig (<it>Ficus carica</it>), within its native range, in Morocco, but as far away as possible from supposed centers of domestication.</p> <p>Results</p> <p>Fig varieties were locally numerous. They were found to be mainly highly local and corresponded to clones propagated vegetatively. Nevertheless these clones were often sufficiently old to have accumulated somatic mutations for selected traits (fig skin color) and at neutral loci (microsatellite markers). Further the pattern of spatial genetic structure was similar to the pattern expected in natural population for a mutation/drift/migration model at equilibrium, with homogeneous levels of local genetic diversity throughout Moroccan traditional agroecosystems.</p> <p>Conclusions</p> <p>We conclude that traditional agroecosystems constitue active incubators of varietal diversity even for clonally propagated crop species, and even when varieties correspond to clones that are often old. As only female fig is cultivated, wild fig and cultivated fig probably constitute a single evolutionary unit within these traditional agroecosystems. Core collections, however useful, are museums and hence cannot serve the same functions as traditional agroecosystems.</p

Heavy metal content in agricultural soils of Mallorca. Relationship with treated wastewater irrigation

Abstract not availabl

La gestión de la ciencia en el Instituto de Investigaciones de Sanidad Vegetal y su contribución a la protección del medio ambiente y la sostenibilidad de los sistemas agrícolas cubanos

La misión del INISAV es Contribuir a la disminución de los riesgos y pérdidas por plagas sin afectar al ambiente sobreuna base sostenible. Su gestión se basa en un modelo de ciencia centrado en el entorno, caracterizado por 4 etapas: laplanificación de las investigaciones, la ejecución, la validación y su adopción en la práctica agrícola. Se describen 3resultados principales de investigación, relativos al Programa de Lucha Biológica (PLB), los Programas de Manejo dePlagas (PMP) y la Eliminación del uso del Bromuro de Metilo (EBM). Se diseñó e implementó la red nacional de 251Laboratorios para la Reproducción de Entomófagos y Entomopatógenos (CREE), 4 plantas para la producción de bioplaguicídas y la generación de 13 productos biológicos y sus tecnologías. Además fueron generalizados Programas deManejo de Plagas en más de 25 cultivos para sistemas convencionales y agroecológicos y la adopción de PMP destinadosa sustituir el bromuro de metilo. Los impactos de los resultados al medio ambiente, la producción agropecuaria, la economía del país, y las comunidades rurales, se demuestran con la reducción de importaciones de plaguicidas químicos, de40 000 t en 1974, a cerca de 3000 t en el 2014. En 1988 el área cultivable beneficiada con bioproductos era de 300 000ha y en el 2014 ascendió a 1 354 000 ha. La eliminación de 80 t de bromuro de metilo en tabaco, 35 t en el resto de lossectores, la reducción de aplicaciones de otros agroquímicos, la incorporación del control biológico y otras medidas demanejo, se consideran la base fundamental para la sostenibilidad en los cultivos. En la actualidad en el 72% del área totalsembrada se realizan aplicaciones de plaguicidas en PMP, de éstas, el 38% solo con biológicos, en el 34% se combinanbiológicos y químicos y en el 28% restante, se aplican otras alternativas fitosanitarias en PMP.La misión del INISAV es Contribuir a la disminución de los riesgos y pérdidas por plagas sin afectar al ambiente sobreuna base sostenible. Su gestión se basa en un modelo de ciencia centrado en el entorno, caracterizado por 4 etapas: laplanificación de las investigaciones, la ejecución, la validación y su adopción en la práctica agrícola. Se describen 3resultados principales de investigación, relativos al Programa de Lucha Biológica (PLB), los Programas de Manejo dePlagas (PMP) y la Eliminación del uso del Bromuro de Metilo (EBM). Se diseñó e implementó la red nacional de 251Laboratorios para la Reproducción de Entomófagos y Entomopatógenos (CREE), 4 plantas para la producción de bioplaguicídas y la generación de 13 productos biológicos y sus tecnologías. Además fueron generalizados Programas deManejo de Plagas en más de 25 cultivos para sistemas convencionales y agroecológicos y la adopción de PMP destinadosa sustituir el bromuro de metilo. Los impactos de los resultados al medio ambiente, la producción agropecuaria, la economía del país, y las comunidades rurales, se demuestran con la reducción de importaciones de plaguicidas químicos, de40 000 t en 1974, a cerca de 3000 t en el 2014. En 1988 el área cultivable beneficiada con bioproductos era de 300 000ha y en el 2014 ascendió a 1 354 000 ha. La eliminación de 80 t de bromuro de metilo en tabaco, 35 t en el resto de lossectores, la reducción de aplicaciones de otros agroquímicos, la incorporación del control biológico y otras medidas demanejo, se consideran la base fundamental para la sostenibilidad en los cultivos. En la actualidad en el 72% del área totalsembrada se realizan aplicaciones de plaguicidas en PMP, de éstas, el 38% solo con biológicos, en el 34% se combinanbiológicos y químicos y en el 28% restante, se aplican otras alternativas fitosanitarias en PMP