642 research outputs found

    Evaluación de la efectividad del manejo agroforestal, en agroecosistemas del corredor biológico Sierra del Rosario-Mil Cumbres

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    For Cuba, improving the management of agricultural systems at the regional level and thus achieving food sovereignty and security has become a matter of national security; the interest in achieving this goal often leads to inefficient agricultural systems that deteriorate natural ecosystems. The agroforestry management developed in 10 agroecosystems in the central-eastern zone of the Sierra del Rosario-Mil Cumbres biological corridor, where productive activities are integrated into a sustainable development model. If effective, it could be extended to other agroecosystems in the mountainous region of the country and thus achieve efficient and sustainable agricultural management models. Consequently, the objective of this research is to evaluate the effectiveness of management in the 10 agroecosystems mentioned above. Using the Practical Manual to evaluate the effectiveness of agroforestry management, obtaining as results: that the diversity index of all agroecosystems is above the threshold of sustainability, that their management contemplates the application of good practices such as: soil conservation and tillage according to topographic characteristics, the use of better adapted varieties and the management of a high diversity of useful species, guarantee 80% of the food sovereignty and security of farmers and their families, the productive chaining for export to the national and international level of some productions and a high quality landscape matrix.Para Cuba perfeccionar el manejo de sistemas agrícolas a nivel regional y así lograr soberanía y seguridad alimentaria, se ha convertido en un asunto de seguridad nacional, el interés por alcanzar dicha meta, en muchas ocasiones desemboca en sistemas agrícolas ineficientes que deterioran los ecosistemas naturales. El manejo agroforestal que se desarrolla en 10 agroecosistemas de la zona centro oriental del corredor biológico Sierra del Rosario-Mil Cumbres, donde se integran las actividades productivas a un modelo de desarrollo sostenible. Podría en caso de ser efectivo, extenderse a otros agroecosistemas de la región montañosa del país y así lograr modelos de gestión agrícola eficientes y sustentables. En consecuencia, el objetivo de esta investigación es evaluar la efectividad de manejo en los 10 agroecosistemas antes señalado. Utilizando el Manual Práctico para evaluar la efectividad del manejo agroforestal, obteniéndose como resultados: que el índice de diversidad de todos los agroecosistemas se encuentra por encima del umbral de la sostenibilidad, que su manejo el que contempla la aplicación de buenas prácticas como: la conservación y laboreo del suelo en función de las características topográficas, el uso de variedades mejor adaptadas y el manejo de una alta diversidad de especies útiles, garantizan en un 80 % la soberanía y seguridad alimentaria de los agricultores y su familia el encadenamiento productivo para la exportación hacia el ámbito nacional e internacional de algunas producciones y una matriz de paisaje de alta calidad

    Evaluación de la efectividad del manejo agroforestal, en agroecosistemas del corredor biológico Sierra del Rosario-Mil Cumbres

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    Para Cuba perfeccionar el manejo de sistemas agrícolas a nivel regional y así lograr soberanía y seguridad alimentaria, se ha convertido en un asunto de seguridad nacional, el interés por alcanzar dicha meta, en muchas ocasiones desemboca en sistemas agrícolas ineficientes que deterioran los ecosistemas naturales. El manejo agroforestal que se desarrolla en 10 agroecosistemas de la zona centro oriental del corredor biológico Sierra del Rosario-Mil Cumbres, donde se integran las actividades productivas a un modelo de desarrollo sostenible. Podría en caso de ser efectivo, extenderse a otros agroecosistemas de la región montañosa del país y así lograr modelos de gestión agrícola eficientes y sustentables. En consecuencia, el objetivo de esta investigación es evaluar la efectividad de manejo en los 10 agroecosistemas antes señalado. Utilizando el Manual Práctico para evaluar la efectividad del manejo agroforestal, obteniéndose como resultados: que el índice de diversidad de todos los agroecosistemas se encuentra por encima del umbral de la sostenibilidad, que su manejo el que contempla la aplicación de buenas prácticas como: la conservación y laboreo del suelo en función de las características topográficas, el uso de variedades mejor adaptadas y el manejo de una alta diversidad de especies útiles, garantizan en un 80 % la soberanía y seguridad alimentaria de los agricultores y su familia el encadenamiento productivo para la exportación hacia el ámbito nacional e internacional de algunas producciones y una matriz de paisaje de alta calidad

    Reporte de Pseudosuccinea columella infectados con Fasciola hepatica en Sierra de los Cuchumatanes, Guatemala

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    Objective. Identify the natural infection of freshwater snails as an intermediate host of Fasciola hepatica in Guatemala. Materials and methods. Freshwater snails were collected in a high-altitude village (3.000 mamsl) from Huehuetenango department, where fasciolasis is endemic. The identification of the snail species was based on the morphological characteristics observed under the stereoscope using an identification key. The trematode phases were searched externally by visual inspection using a light source, and internally by dissection and visual inspection of the tissues under a stereoscope and microscope. Results. 260 snails were found and identified as Pseudosuccinea columella. Two of them were found naturally infected with larval phases of F. hepatica. Conclusions. This is the first report of P. columella carrying phases of F. hepatica in the highlands of Guatemala. It is necessary to increase the research of the ecology of this parasite in other understudied areas in Guatemala and Central America, due to the latent risk of infection for populations of herbivorous animals and humans.Objetivo. Identificar la infección natural de caracoles de agua dulce con Fasciola hepatica en una localidad del altiplano de Guatemala. Materiales y métodos. Se colectaron caracoles de agua dulce en una aldea endémica de fascioliasis, en la localidad de Paquix, en el departamento de Huehuetenango, ubicado a ~3.300 msnm. La identificación de la especie de caracol se basó en las características morfológicas observadas por estereoscopio usando una clave de identificación. La búsqueda de fases del trematodo se realizó mediante la inspección visual externa con fuente de luz y la disección e inspección visual dentro del molusco bajo estereoscopio y microscopio. Resultados. 260 caracoles fueron encontrados e identificados como Pseudosuccinea columella. Se examinaron los especímenes colectados y se encontraron dos caracoles infectados de forma natural con fases larvarias de F. hepatica. Conclusiones. Este es el primer reporte de este hospedero intermediario portando formas de F. hepatica en Guatemala. Es necesario aumentar los reportes de este parásito y de sus interacciones ecológicas en otras áreas no estudiadas de Guatemala y Centro América, debido al riesgo latente de infección para poblaciones de animales herbívoros y humanos

    Las ciencias sociales en el noreste de México.

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    Texto colectivo que incluye seis ensayos donde se reflexiona sobre el estado que guardan las ciencias sociales en el noreste de México: antropología, comunicación, economía, geografía, historia y sociología.Redactado por miembros del Grupo Gente (Grupo de Estudios sobre el Noreste de México y Texas) bajo la coordinación de César Morado y Lucila Hinojosa

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

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    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

    Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

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    The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe

    Search for supersymmetry in events with one lepton and multiple jets in proton-proton collisions at root s=13 TeV

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    Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

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    A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV

    Search for anomalous couplings in boosted WW/WZ -> l nu q(q)over-bar production in proton-proton collisions at root s=8TeV

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    Measurement of the top quark mass using charged particles in pp collisions at root s=8 TeV

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