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Search Results: 1 - 10 of 219649 matches for " Dayamí; Gato Cárdenas "
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Métodos alternativos en la conservación de Trichoderma harzianum Rifai
Rodríguez Batista,Dayamí; Gato Cárdenas,Yohana;
Fitosanidad , 2010,
Abstract: conservation of trichoderma harzianum rifai a-34 strain, used in mass production, was evaluated stored in silica gel, distilled water and under mineral oil. viability, morphological characters and antagonist capacity had been evaluated for one year. samples conserved in sterile distilled water and under mineral oil showed no differences from the original culture stored in potato dextrose agar at 40 c, while those conserved in silica gel were viable for three months only.
Métodos de conservación y formulación de trichoderma harzianum rifai
Gato Cárdenas,Yohana;
Fitosanidad , 2010,
Abstract: preservation of microorganisms is quite remarkable in order to ensure viability and morphologic, physiologic and genetic integrity of strains cultures that let use them in production with the maintenance of their original characteristic. the efficiency of some alternative methods is evaluated currently, to diminish conservation costs. this work approaches, in simplified structure, conservation methods of biocontrol fungi, their main characteristics, advantages and disadvantages of the use, the genus of fungi to be conserved by these methods, according to diverse authors. moreover, it makes reference to the formulation and stability in storage of fungal biopesticide, as important point to obtain the final product, making emphasis in the antagonistic fungus trichoderma harzianum rifai.
An Iterative Method for Solving Two Special Cases of Lane-Emden Type Equation  [PDF]
Pedro Pablo Cárdenas Alzate
American Journal of Computational Mathematics (AJCM) , 2014, DOI: 10.4236/ajcm.2014.43021
Abstract:

In this work we apply the differential transformation method or DTM for solving some classes of Lane-Emden type equations as a model for the dimensionless density distribution in an isothermal gas sphere \"\" and as a study of the gravitational potential of (white-dwarf) stars ,\"\" which are nonlinear ordinary differential equations on the semi-infinite domain [1] [2]. The efficiency of the DTM is illustrated by investigating the convergence results for this type of the Lane-Emden equations. The numerical results show the reliability and accuracy of this method.

A Survey of the Implementation of Numerical Schemes for Linear Advection Equation  [PDF]
Pedro Pablo Cárdenas Alzate
Advances in Pure Mathematics (APM) , 2014, DOI: 10.4236/apm.2014.48052
Abstract:

The interpolation method in a semi-Lagrangian scheme is decisive to its performance. Given the number of grid points one is considering to use for the interpolation, it does not necessarily follow that maximum formal accuracy should give the best results. For the advection equation, the driving force of this method is the method of the characteristics, which accounts for the flow of information in the model equation. This leads naturally to an interpolation problem since the foot point is not in general located on a grid point. We use another interpolation scheme that will allow achieving the high order for the box initial condition.

A Survey of the Implementation of Numerical Schemes for the Heat Equation Using Forward Euler in Time  [PDF]
Pedro Pablo Cárdenas Alzate
Journal of Applied Mathematics and Physics (JAMP) , 2014, DOI: 10.4236/jamp.2014.213135
Abstract: We establish the conditions for the compute of the Global Truncation Error (GTE), stability restriction on the time step and we prove the consistency using forward Euler in time and a fourth order discretization in space for Heat Equation with smooth initial conditions and Dirichlet boundary conditions.
A Special Case of Variational Formulation for Two-Point Boundary Value Problem in L2(Ω)  [PDF]
Pedro Pablo Cárdenas Alzate
Applied Mathematics (AM) , 2015, DOI: 10.4236/am.2015.64065
Abstract: We consider the nonlinear boundary value problems for elliptic partial differential equations and using a maximum principle for this problem we show uniqueness and continuous dependence on data. We use the strong version of the maximum principle to prove that all solutions of two-point BVP are positives and we also show a numerical example by applying finite difference method for a two-point BVP in one dimension based on discrete version of the maximum principle.
Assessment and Monitoring Damage by Coraebus florentinus (Coleoptera: Buprestidae) in Mediterranean Oak Forests  [PDF]
Ana M. Cárdenas, Patricia Gallardo
Open Journal of Ecology (OJE) , 2018, DOI: 10.4236/oje.2018.85020
Abstract: Coraebus florentinus (Herbst) is a wood borer beetle that damages the most abundant Quercus species making up the Mediterranean forests. Damage is due to the feeding activity of the larvae which cuts the sap flow into the branch where it develops, drying it. In the last decades, the geographical range and the damage records of this species have expanded northwardly as a result of the climate global change since warmer conditions favor higher reproduction and quicker development of this species. On this paper, historical series of data after ten years evaluating damages by C. florentinus in Hornachuelos Natural Park (Southern Spain) are analyzed under the perspective of the environmental temperature increase linked to the global climate change. The assessment was done between 2007 and 2017, in two sampling plots of Mediterranean mixed-oak forests where holm and cork oaks are the predominant tree species. Results show that the infestation levels of this species at the beginning of the assessment period were higher than those described previously in the nineties and that they increased progressively during the monitoring time. The results also agree with the expansion of its distribution areas noticed in other areas of Europe. The foreseeable rising of damages of C. florentinus is discussed, at greater scale, under the perspective of future scenery of environmental warming and oaks decaying by losing fitness due to higher soil aridity.
Selección de leguminosas herbáceas para el fomento de cobertura en plantaciones de naranja Valencia late Selection of herbaceous legumes for the development of cover in Valencia late orange plantations
Dayamí Fontes,R Machado,Nieves Cubillas,C Mazorra
Pastos y Forrajes , 2009,
Abstract: El establecimiento de leguminosas herbáceas dentro de las áreas de frutales precisa de estudios que demuestren la compatibilidad de estas asociaciones, con vista a mejorar la producción en estos agroecosistemas. El objetivo del presente trabajo fue seleccionar la especie leguminosa más adecuada para emplearla como cobertura viva en plantaciones de naranja Valencia late, sobre la base de su caracterización morfoagronómica. El estudio se realizó en áreas de la Empresa de Cítricos Ciego de ávila. Para ello se establecieron parcelas de 3 m2, sobre un suelo Ferralítico Rojo compactado, donde no se había aplicado fertilizantes ni herbicidas. Se utilizaron 14 tratamientos y se midieron los siguientes indicadores: emergencia (a los 7, 14, 21, 28 y 35 días después de la siembra en cada parcela), altura (cm), cobertura foliar (%) y producción de semillas (t ha-1). De acuerdo con los resultados, Teramnus labialis fue la especie más adecuada para usarla como cobertura viva en plantaciones citrícolas, en correspondencia con el porcentaje de emergencia, el área cubierta, la altura estacional y la producción de semilla alcanzada durante el proceso de evaluación, por lo que se recomienda su utilización en los ecosistemas citrícolas de naranja V. late de Ciego de ávila. The establishment of herbaceous legumes within fruit tree areas requires studies that prove the compatibility of these associations, aiming at improving production in these agroecosystems. The objective of this work was to select the most adequate legume species to be used as live cover in Valencia late orange plantations, based on their morphoagronomic characterization. The study was conducted in areas of the Ciego de ávila Citrus Fruit Enterprise. For such purpose 3 m2 plots were established on a compacted Ferralitic Red soil, where neither fertilizers nor herbicides had been applied. Fourteen treatments were used and the following indicators were measured: emergence (7, 14, 21, 28 and 35 days after planting in each plot), height (cm), leaf cover (%) and seed production (t ha-1). According to the results, Teramnus labialis was the most adequate species to be used as live cover in citrus fruit plantations, in correspondence with the emergence percentage, the area covered, seasonal height and seed production reached during the evaluation process, for which its use is recommended in citrus fruit systems of V. late orange in Ciego de ávila.
?Y VERáS COMO QUIEREN EN CHILE...?: Un estudio sobre el prejuicio hacia los inmigrantes bolivianos por parte de los jóvenes chilenos
Cárdenas C,Manuel;
Ultima década , 2006, DOI: 10.4067/S0718-22362006000100006
Abstract: the main objective of this study was to investigate in the forms that the prejudice takes towards the immigrants of bolivian origin. we have used the typology that stem from the scales of subtle and blatant prejudice (pettigrew and meertens, 1995) to compare to the subjects in different psycosocial variables relevant in the existing literature on prejudice and racism. the sample was formed of 167 school students of last year of average education, belonging to diverse education centers both public and private of the antofa-gasta city, chile.
Psicología social y contexto: sobre la fuerza de las situaciones sociales perversas
Manuel Cárdenas C.
Límite , 2006,
Abstract: Para entender la conducta de los sujetos y comprender lo que pasa al interior de los individuos haríamos mejor si dejásemos de mirar únicamente al interior de éstos y nos centramos en las condiciones sociales que sirven de marco para su acción. De lo que se trata es de mirar afuera para comprender lo que pasa dentro, de entender que las acciones correctivas sobre ciertos fenómenos sociales sólo son posibles de ser abordadas desde los marcos que delimitan la acción de los individuos y sus relaciones, y no pueden ser achacadas exclusivamente a éstos. Para abordar este tema se hace referencia a tres conocidos experimentos en Psicología Social que nos muestran qué ocurre cuando los sujetos son puestos en situaciones perversas.
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