745 research outputs found

    Preservación del bambú por el método de inmersión en la región de Cuetzalan del progreso Puebla, México

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    En el presente trabajo se muestra la forma de optimizar el método de preservación por inmersión del bambú en la región de de Cuetzalan del Progreso Puebla. La investigación se llevo a cabo en el taller de bambú en la sociedad cooperativa Tosepan ojtasentekitini ubicada en el Municipio de Cuetzalan del Estado de Puebla. Tiene como propósito principal el de recomendar la cantidad ideal de solución en el tiempo adecuado de inmersión para su preservación. Se realizo un diseño experimental completamente al azar con 2 factores. Tomando 12 repeticiones para cada tratamiento, con tres especies Guadua aculeata, Bambusa oldhamii, Guadua angustifolia. El preservante utilizado consistió en una mezcla de compuestos de boro, bórax (Na2B4O710H2O) y ácido bórico (H3BO3) en proporción 1:1. Los principales resultados de la investigación realizada, se encontró que para la especie Guadua aculeata se puede disminuir la concentración utilizada actualmente al 50 % manteniendo los culmos en 4 días de inmersión ya que no existe una variación estadística significativa en relación con mayor concentración o mayor número de días en inmersión por lo tanto es posible optimizar gastos y tiempo al realizar el tratamiento preservante

    Análisis de los índices de vegetación NDVI, GNDVI y NDRE para la caracterización del cultivo de café (Coffea arabica)

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    Recently, vegetation indices have been used in order to determine the type of cover, with the interest of its temporal variation evaluation, or with the aim of determining the crops health status from estimation of some characteristics such as plant vigor, chlorophyll content, nutritional status or water status. Several studies have put forward a range of vegetation indices that use different bands in the visible and near-infrared spectrum to obtain characteristics of interest. In this study, statistical differences between the NDVI, GNDVI and NDRE vegetation indices estimated from aerial images taken at 30 m above the canopy of an experimental Coffea arabica crop were evaluated. Spearman correlation coefficient showed a higher correlation between the NDVI and GNDVI indices compared to that found between either of them and NDRE. In addition to this, it was observed that, according to the values of the coefficient of variation, and the subsequent analysis of the histograms, the NDRE index presented a greater sensitivity to variation in plant vigor, which would suggest a greater potential to characterize the state of development of coffee cultivation, compared to other studied indices.Los índices de vegetación se han usado en los últimos años con el fin de determinar el tipo de cobertura, para evaluar su variación temporal, o para determinar el estado de salud de cultivos a partir de estimaciones de características como vigor vegetal, contenido de clorofila, estado nutricional o estado hídrico. En diversos estudios se han propuesto una variedad de índices de vegetación que usan diferentes bandas en el espectro visible e infrarrojo cercano con el fin de obtener características de interés. En este estudio se evaluaron las diferencias estadísticas entre los índices de vegetación NDVI, GNDVI y NDRE, estimados a partir de imágenes aéreas tomadas a 30 m del dosel de un cultivo experimental de la especie vegetal Coffea arabica. El coeficiente de correlación de Spearman mostró que la correlación es mayor entre los índices NDVI y GNDVI en comparación a la correlación presentada entre cualquiera de ellos y el índice NDRE. Además de ello, se observó que de acuerdo con los valores del coeficiente de variación, y el análisis posterior de los histogramas, el índice NDRE presentó una mayor sensibilidad ante la variación de vigor vegetal, lo que sugeriría un mayor potencial a la hora de caracterizar el estado de desarrollo del cultivo de café, frente a los otros índices estudiados

    Diversity of mosquitoes and the aquatic insects associated with their oviposition sites along the Pacific coast of Mexico

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    Background: The abundance, richness and diversity of mosquitoes and aquatic insects associated with their oviposition sites were surveyed along eight states of the Pacific coast of Mexico. Diversity was estimated using the Shannon index (H’), similarity measures and cluster analysis. Methods: Oviposition sites were sampled during 2–3 months per year, over a three year period. Field collected larvae and pupae were reared and identified to species following adult emergence. Aquatic insects present at oviposition sites were also collected, counted and identified to species or genus. Results: In total, 15 genera and 74 species of mosquitoes were identified: Anopheles pseudopunctipennis, An. albimanus and Aedes aegypti were the most abundant and widely-distributed species, representing 47% of total mosquito individuals sampled. New species records for certain states are reported. Anopheline diversity was lowest in Sinaloa state (H’ = 0.54) and highest in Chiapas (H’ = 1.61) and Michoacán (H’ = 1.56), whereas culicid diversity was lowest in Michoacán (H’ = 1.93), Colima (H’ = 1.95), Sinaloa (H’ = 1.99) and Jalisco (H’ = 2.01) and highest in Chiapas (H’ = 2.66). In total, 10 orders, 57 families, 166 genera and 247 species of aquatic insects were identified in samples. Aquatic insect diversity was highest in Chiapas, Oaxaca and Michoacán (H’ = 3.60-3.75). Mosquito larval/pupal abundance was not correlated with that of predatory Coleoptera and Hemiptera. Conclusion: This represents the first update on the diversity and geographic distribution of the mosquitoes and aquatic insects of Mexico in over five decades. This information has been cataloged in Mexico’s National Biodiversity Information System (SNIB-CONABIO) for public inspection

    RICORS2040 : The need for collaborative research in chronic kidney disease

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    Chronic kidney disease (CKD) is a silent and poorly known killer. The current concept of CKD is relatively young and uptake by the public, physicians and health authorities is not widespread. Physicians still confuse CKD with chronic kidney insufficiency or failure. For the wider public and health authorities, CKD evokes kidney replacement therapy (KRT). In Spain, the prevalence of KRT is 0.13%. Thus health authorities may consider CKD a non-issue: very few persons eventually need KRT and, for those in whom kidneys fail, the problem is 'solved' by dialysis or kidney transplantation. However, KRT is the tip of the iceberg in the burden of CKD. The main burden of CKD is accelerated ageing and premature death. The cut-off points for kidney function and kidney damage indexes that define CKD also mark an increased risk for all-cause premature death. CKD is the most prevalent risk factor for lethal coronavirus disease 2019 (COVID-19) and the factor that most increases the risk of death in COVID-19, after old age. Men and women undergoing KRT still have an annual mortality that is 10- to 100-fold higher than similar-age peers, and life expectancy is shortened by ~40 years for young persons on dialysis and by 15 years for young persons with a functioning kidney graft. CKD is expected to become the fifth greatest global cause of death by 2040 and the second greatest cause of death in Spain before the end of the century, a time when one in four Spaniards will have CKD. However, by 2022, CKD will become the only top-15 global predicted cause of death that is not supported by a dedicated well-funded Centres for Biomedical Research (CIBER) network structure in Spain. Realizing the underestimation of the CKD burden of disease by health authorities, the Decade of the Kidney initiative for 2020-2030 was launched by the American Association of Kidney Patients and the European Kidney Health Alliance. Leading Spanish kidney researchers grouped in the kidney collaborative research network Red de Investigación Renal have now applied for the Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS) call for collaborative research in Spain with the support of the Spanish Society of Nephrology, Federación Nacional de Asociaciones para la Lucha Contra las Enfermedades del Riñón and ONT: RICORS2040 aims to prevent the dire predictions for the global 2040 burden of CKD from becoming true

    Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

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    A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

    Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

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    A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

    Measurements of Higgs boson production cross sections and couplings in the diphoton decay channel at root s=13 TeV

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    Measurements of Higgs boson production cross sections and couplings in events where the Higgs boson decays into a pair of photons are reported. Events are selected from a sample of proton-proton collisions at root s = 13TeV collected by the CMS detector at the LHC from 2016 to 2018, corresponding to an integrated luminosity of 137 fb(-1). Analysis categories enriched in Higgs boson events produced via gluon fusion, vector boson fusion, vector boson associated production, and production associated with top quarks are constructed. The total Higgs boson signal strength, relative to the standard model (SM) prediction, is measured to be 1.12 +/- 0.09. Other properties of the Higgs boson are measured, including SM signal strength modifiers, production cross sections, and its couplings to other particles. These include the most precise measurements of gluon fusion and vector boson fusion Higgs boson production in several different kinematic regions, the first measurement of Higgs boson production in association with a top quark pair in five regions of the Higgs boson transverse momentum, and an upper limit on the rate of Higgs boson production in association with a single top quark. All results are found to be in agreement with the SM expectations.Peer reviewe
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