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Search Results: 1 - 10 of 52202 matches for " Luis Roberto;Mena-Covarrubias "
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Incidencia y sintomatología de cinco virus en parcelas comerciales de chile seco en Aguascalientes, San Luis Potosí y Zacatecas, México
Velásquez-Valle, Rodolfo;Reveles-Torres, Luis Roberto;Mena-Covarrubias, Jaime;
Revista mexicana de ciencias agrícolas , 2012,
Abstract: world-wide the chili pepper crop is affected by more than 60 viral diseases, although very little is known about them in the area of dry pepper plantation in northern-central mexico. consequently, the aims of this work were to identify the presence of the virus and the associated symptoms in commercial dry pepper fields of the states of zacatecas, san luis potosí, and aguascalientes, mexico. mirasol and ancho pepper plants were sampled and the presence of symptoms such as dwarfing, chlorosis, leaf deformation, defoliation, vascular necrosis and joined branches, were recorded. samples were analyzed using das-elisa with the antisera of the tobacco mosaic virus (tobacco mosaic virus: tmv), cucumber mosaic virus (cucumber mosaic virus: cmv), potato virus y (potato virus y: pvy), pepper mottle virus (pepper mottle virus: pepmov), and tobacco etch virus (tobacco etch virus: tev). these viruses were identified in pepper plants collected in dry pepper fields located in the three states mentioned earlier.
Incidencia y sintomatología de cinco virus en parcelas comerciales de chile seco en Aguascalientes, San Luis Potosí y Zacatecas, México Incidence and symptomatology of five viruses in commercial dry chili pepper fields in Aguascalientes, San Luis Potosí, and Zacatecas, Mexico
Rodolfo Velásquez-Valle,Luis Roberto Reveles-Torres,Jaime Mena-Covarrubias
Revista mexicana de ciencias agrícolas , 2012,
Abstract: A nivel mundial el cultivo de chile es afectado por más de 60 enfermedades virales; sin embargo, poco se conoce acerca de ellas en el área productora de chile seco del norte centro de México por lo que el objetivo del presente trabajo consistió en detectar la presencia y sintomatología de cinco virus en parcelas comerciales de chile seco en los estados mencionados. Plantas de chile de los tipos mirasol y ancho fueron muestreadas y se anotó la presencia de síntomas como enanismo, clorosis, deformación de hojas, defoliación, necrosis vascular y ramas unidas. Las muestras fueron analizadas mediante la técnica DAS-ELISA empleando los antisueros para el virus del mosaico del tabaco (Tobacco mosaic virus: TMV), mosaico del pepino (Cucumber mosaic virus: CMV), Y de la papa (Potato virus Y: PVY), moteado del chile (Pepper mottle virus: PepMoV) y jaspeado del tabaco (Tobacco etch virus: TEV). Esos virus fueron identificados en plantas de chile colectadas en las parcelas comerciales de chile seco de los tres estados antes mencionados. World-wide the chili pepper crop is affected by more than 60 viral diseases, although very little is known about them in the area of dry pepper plantation in northern-central Mexico. Consequently, the aims of this work were to identify the presence of the virus and the associated symptoms in commercial dry pepper fields of the states of Zacatecas, San Luis Potosí, and Aguascalientes, Mexico. Mirasol and ancho pepper plants were sampled and the presence of symptoms such as dwarfing, chlorosis, leaf deformation, defoliation, vascular necrosis and joined branches, were recorded. Samples were analyzed using DAS-ELISA with the antisera of the tobacco mosaic virus (Tobacco mosaic virus: TMV), cucumber mosaic virus (Cucumber mosaic virus: CMV), potato virus Y (Potato virus Y: PVY), pepper mottle virus (Pepper mottle virus: PepMoV), and tobacco etch virus (Tobacco etch virus: TEV). These viruses were identified in pepper plants collected in dry pepper fields located in the three states mentioned earlier.
Retraso de la cosecha en nopal tunero cv. Cristalina
Zegbe, J. A.;Mena-Covarrubias, J.;
Revista Chapingo. Serie horticultura , 2008,
Abstract: cactus pear fruit prices drop significantly during august and september in north-central mexico because harvest peak is concentrated on those months. harvest delay is an option to alleviate this problem and it was the aim of the research conducted. four-year-old cactus pear trees cv. cristalina were used in this trial. the treatments were: 1) leaving the normal development of the first vegetative and reproductive flux, which was considered as control, and 2) inducing a second vegetative and reproductive flux. the second treatment set back the harvest by 45 days, increased weight and flesh firmness of fruit, but yield was reduced by 65% compared with control. after four weeks in storage, flesh firmness and dry mass concentration were higher in out of season fruits. it is possible to delay the harvest period of the cv. cristalina, however, additional research work is needed under different environments and other cactus pear cultivars with high commercial value.
Rendimiento y calidad de chile seco 'Mirasol' cultivado bajo riego parcial de la raíz
Serna-Pérez, Alfonso;Zegbe, Jorge Artemio;Mena-Covarrubias, Jaime;
Revista Chapingo. Serie horticultura , 2011,
Abstract: the efficient use of water resources is mandatory for the dry chili producing area of zacatecas. the objective of this study was to compare two types of partial rootzone drying (prd) against commercial irrigation (ci) in relation to yield and fruit quality, irrigation water use efficiency (iwue), and pepper wilt incidence (wi) of chilli cv. 'mirasol'. prd treatments were prd50 on which 50% of ci was applied alternately to both sides of the root zone, and prd50+20 which was similar to prd50, but additionally 20% of ci was applied to the drying side of the root system. prd50 and prd50+20 promoted water savings compared with ci. the fruit quality categories of dry chili and yield were similar among treatments, but yield tended to decrease in prd50 and prd50+20 in 2009. the iwue tended to increase in prd50 and prd50+20 relative to ci. in 2008 wi was the same among treatments, but in 2009 it increased in the prd treatments. soil water saturation by continuous precipitations after irrigation events partially explained the increase in wi, and therefore the reduction in yield in the 2009. nevertheless, prd50 tended to increase iwue by 28 % and to reduce the volume of water applied by 32 % with respect to ci. therefore, the rpr is a promising strategy for sustainability of this production system.
Remover las yemas reproductivas afecta la época de cosecha del nopal tunero?
Jorge A. Zegbe,Jaime Mena Covarrubias
Revista fitotecnia mexicana , 2008,
Abstract: Producir fruta de nopal tunero (Opuntia spp) fuera de temporada es importante para alcanzar precios más altos. Este trabajo probó la hipótesis de que eliminar las yemas reproductivas podría retrasar o adelantar la maduración de la fruta de los cultivares Cristalina y Rojo Liso . Los tratamientos consistieron en eliminar las yemas reproductivas más desarrolladas, o bien las más jóvenes, más un testigo que consistió en permitir el desarrollo normal de las yemas reproductivas, excepto las yemas dobles que fueron eliminadas. La eliminación de las yemas reproductivas más desarrolladas o las más jóvenes ni atrasó ni adelantó la cosecha en ambos cultivares, por lo que esta estrategia no es útil para modificar el tiempo de la cosecha; pero la aplicación de estos tratamientos aumentó el tama o del fruto y redujo el rendimiento en ambos cultivares, aunque no significativamente en Cristalina . Así, con el raleo de yemas se logró producir fruto de mayor tama o que en las plantas testigo, lo cual es importante para un mercado selecto nacional y de exportación.
Evaluación conductual en la empresa
Luis López Mena
Revista Latinoamericana de Psicología , 1993,
Abstract: Este trabajo revisa las características actuales de la evaluación de la conducta de los trabajadores en las organizaciones, especialmente en las empresas. El estudio de la literatura y de las investigaciones efectuadas se ala al menos dos grandes formas de evaluación del comportamiento en las empresas: los rasgos y las medidas económicas. El análisis revela que ambos tipos de medidas resultan subjetivas, globales y poco confiables, pese a lo cual siguen siendo mayoritariamente empleados por los psicólogos industriales. Como alternativa se propone emplear en las organizaciones la evaluación conductual, es decir: medidas orientadas hacia la conducta en el trabajo, empleando dise os de investigación como la Línea Base Múltiple, y se se alan los requisitos y características que el psicólogo industrial debería considerar para utilizar los procedimientos de evaluación conductual en las empresas.
Responses of bats to forest fragmentation at Pozuzo, Peru Respuestas de los murciélagos a la fragmentación del bosque en Pozuzo, Perú
José Luis Mena
Revista Peruana de Biología , 2011,
Abstract: Forest fragmentation and deforestation are among the major threats to Peruvian bats conservation. Unfortunately, information about the effects of these threats above 500 m elevation is lacking. In this study, I assessed bat responses to fragmentation in Pozuzo (Pasco) at a landscape scale approach. I evaluate two hypotheses regarding the role of bats as indicators of habitat disturbance. The first prediction says that landscapes highly disturbed will show higher abundances of habitat generalist species such as frugivorous bats belonging to the subfamilies Stenodermatinae and Carollinae. The second prediction regards that landscapes with greater forest cover will show higher abundance of habitat specialist species such as animalivorous bat species belonging to the subfamily Phyllostominae, a guild sensitive to forest disturbance. I found evidence supporting the animalivorous hypothesis but it was partial to the frugivorous hypothesis. This study highlights the importance of forest fragments to bat conservation in human-modified landscapes. Resumen La deforestación y la fragmentación de los bosques son unas de las amenazas más importantes para la supervivencia de los murciélagos en el Perú. Sin embargo, se conoce muy poco sobre el impacto de estas en sitios o lugares por encima de los 500 m de altitud. En este estudio, considerando la escala de paisaje, analicé las respuestas de los murciélagos (Chiroptera) a la fragmentación en un paisaje perturbado en Pozuzo (Región Pasco). En ese sentido, considerando el rol de los murciélagos como indicadores de perturbación del hábitat, planteé dos hipótesis. Una primera predicción se refirió a que muestras de paisajes altamente fragmentados y con mayor cantidad de bordes presentarán una mayor abundancia de especies frugívoras que prosperan en hábitats perturbados (Stenodermatinae y Carollinae). La segunda predicción se refería a que muestras de paisaje con una mayor cobertura de bosque deberían tener una mayor abundancia de murciélagos del gremio animalívoro (Phyllostominae), ya que estos son sensibles a las perturbaciones y suelen ser más abundantes en bosques maduros y en buen estado de conservación. Encontré evidencia apoyando la predicción sobre el gremio animalívoro pero apoyo parcial para la predicción sobre los frugívoros. Se resalta la importancia de la conservación de los fragmentos de bosque para asegurar la supervivencia de los murciélagos y de los servicios que estos prestan, en especial para la regeneración del bosque en paisajes tropicales modificados por las actividades humanas.
Púrpura trombocitopénica autoinmune. Informe de 108 casos
Covarrubias Espinoza, Roberto;Sotelo Cruz, Norberto;Hurtado Valenzuela, Jaime Gabriel;
Boletín médico del Hospital Infantil de México , 2004,
Abstract: introduction. autoimmmune thrombocytopenic purpura (atp) is a hemorrhagic disease with a more frequent presentation in infancy. could appear with an all level of bleeding and sometimes involves the central nervous system (cns). it is divided in 2 groups: the acute thrombocytopenic purpura (a-atp) and the chronic form (c-atp). objectives. to identify the presentation, evaluation and therapeutic modalities applied to patients with a-atp. material and methods. we realized a retrospective study in the internal medicine. unit at the children's hospital in the state of sonora, detecting 108 patients with the diagnosis of atp in the last 10 years. the variables studied were: age gender, clinical features, complications, treatment and evolution. results. we observed that the disease was more frequent in children under 6 years of age; there were no significant differences regarding gender, and the most common symptoms were bleeding of mucocutaneous tissues: 89% of the patients received treatment with prednisone; gammaglobulin and danazol in 4.5% and splenectomy 11 cases (14.5%); no evidence of mortality due to cns hemorrhage; 85% presented remission and 15% went to chronicity. urgent splenectomy was not required in our group, but these who underwent this type of surgery were cured in 91%. conclusions. being atp an autoimmune disease the majority of patients may go under remission even without treatment; however, we have observed better results in the use of steroids, shortening their hospital stay; in this series we did not had any of the most severe complications of atp.
Appraisal of Five Clinical Guidelines for the Management of Hypertension in Andean Countries and Europe  [PDF]
Juan Moreira, Edison Jaramillo, Mariella Anselmi, Roberto Sempertegui, Patricia Ortiz, Maria Belen Mena, Gianni Tognoni
World Journal of Cardiovascular Diseases (WJCD) , 2014, DOI: 10.4236/wjcd.2014.45028
Abstract: There is global concern on the methodological limitations, transferability and effectiveness of clinical practice guidelines (CPGs) for chronic non-communicable diseases, particularly for hypertension. Bolivia, Ecuador and Peru have regularly produced CPGs; however no formal assessment has been done on their contents, transferability and effectiveness. The past decade saw significant migration from Andean countries to Europe. Knowing how European CPGs compare with those produced in Andean countries is necessary to recommend future changes targeted to the migrant population. A systematic search of CPGs was done on indexed databases and non-indexed publications. Recognized and approved CPGs were identified by technical officers in the Ministries of Health of the respective countries. The guidelines of the European Society of hypertension and four selected CPGs from the Andean countries were assessed by two independent evaluators using the “Agree II instrument for assessing clinical practice guidelines, AGREE II Consortium, May 2009”. Comparison of the CPGs is based on the six domain scores provided by the Agree II instrument. The overall score of CPGs ranged from 1.85 to 2.94 of 6 maximum possible. The European CPG scored highest in 3 of 6 domains compared, most notably in rigor of development. Average domain scores for clarity of presentation (0.84) and scope and purpose (0.64) were highest scores for applicability (0.30). Stakeholder involvement (0.28) and rigor of development (0.17) were the lowest. The CPGs assessed appear to fail meeting the standards of quality and pertinence. They show a progressive worsening from domains declaring good intentions of being clear, to those which measure their hard aspects and implications.
Diversidad y patrones reproductivos de quirópteros en una área urbana de Lima, Perú
José Luis Mena,Martha Williams de Castro
Ecología Aplicada , 2002,
Abstract: Resultan particularmente escasos los estudios sobre vertebrados en áreas que soportan la acción modificadora del hombre. Los estudios sobre la biología reproductiva de murciélagos neotropicales indican que la mayoría se reproducen estacionalmente, de allí que surgió la necesidad de documentar este comportamiento en el campus de la Universidad Nacional Agraria La Molina, área urbana de la ciudad de Lima, Perú. Las colectas se efectuaron de octubre de 1995 a septiembre de 1996 con el objeto de reconocer los patrones reproductivos de las especies. Se capturó un total de 180 individuos, registrándose cuatro especies pertenecientes a las familias Phyllostomidae y Vespertilionidae. Las especies más abundantes fueron Glossophaga soricina y Artibeus fraterculus. Para estas especies, se confirman los patrones postulados de poliestría bimodal. Los resultados revelan que ambas especies siguen este patrón y que las hembras de G. soricina y A. fraterculus por lo menos tienen un período de estro post parto por a o.
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