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Search Results: 1 - 10 of 434187 matches for " Víctor J; Ramírez "
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Woodland communities in the Chilean cold-temperate zone (Baker and Pascua basins): Floristic composition and morpho-ecological transition
VIDAL,OSVALDO J; BANNISTER,JAN R; SANDOVAL,VíCTOR; PéREZ,YESSICA; RAMíREZ,CARLOS;
Gayana. Botánica , 2011, DOI: 10.4067/S0717-66432011000200004
Abstract: this study describes the floristic composition and morpho-ecological transition of woodlands along a climatic gradient in the southern cold temperate zone of chilean patagonia. a total of 256 phytosociological relevés were performed across a 150 km ne-sw transect to record vascular plant species. classification (cluster analysis) and ordination (principal component analysis) techniques were used to segregate and examine the communities. biodiversity indicators including richness and abundances of species natives and exotics, importance values, raunkiaer plant life-forms, diversity indices and indicator species were calculated to describe community attributes. beta diversity was analysed using the jaccard index. additionally, the current anthropogenic disturbances affecting this vegetation are discussed. in total, 11 woodland communities belonging to 3 morpho-ecological groups were segregated: a) meso-hygromorphic woodlands belonging to the baker basin, mostly composed of deciduous forests containing relatively moderate values of richness and diversity but high richness of exotics, b) hygromorphic woodlands belonging to the southern segment of the baker basin and along the pascua basin, composed of evergreen forest containing the relatively highest values of richness and diversity and very low richness of exotics and c) high-andean dwarf woodlands distributed at high elevations in both basins, composed of deciduous krummholz containing the lowest richness and diversity and no exotics. the replacement of deciduous by evergreen communities at low elevations occurs around the latitude 48°s. anthropogenic disturbances like logging by rural landowners, overgrazing by livestock and road construction are promoting biological invasions in the baker basin forests, while the forests in the pascua basin remain pristine since no human population occurs there
Ultraestructura de callos embriogénicos y no embriogénicos de banano williams (aaa, musa spp.)
Ramírez V,Maribel del C; de García,Eva; Finol,ctor J;
Agronomía Tropical , 2006,
Abstract: the ultrastructural studies of somatic embryogenesis are very important to understand and improve this morphogenetic process. in this sense the main objective of this research is the ultrastructural characterization of embryogenic and non embryogenic calluses from williams? banana (musa spp.). in the cells of both types of tissues, the cell wall (primary cell wall and middle lamella), plasma membrane, cytoplasm (endoplasmatic reticulum, vacuolar membrane and mitochondrias), and vacuoles, were observed. the cne presented a less dense cytoplasm and thin walls. the ce showed small isodiametric cells, with small vacuoles and thick walls.
Leishmaniasis visceral en un canino
Zabala,Eduardo E; Ramírez,Oneyda J; Bermúdez,Víctor;
Revista de la Facultad de Ciencias Veterinarias , 2005,
Abstract: visceral leishmaniasis is a worldwide distributed infectious and zoonotic disease affecting people, domestic, and wildlife animals.? it is caused by a diphasic protozoan of the genus leishmania, involving distinct species that differs geographically between the old and new world, and its arthropod vectors being from genuses phlebotomus and lutzomyia, responsible for? transmission in those areas, respectively.? leishmania chagasi from the donovani complex, has been demonstrated as a cause for visceral leishmaniasis in central and south america and its? sero prevalence, among aragua state canine population, has been shown by a field study. a four months old, male canine boxer was presented with concern for acute onset of respiratory distress and exercise intolerance.? physical examination revealed hyperthermia, generalized lymphoadenomegaly, severe dysrrittmia and tachycardia altering rhythm and heart rate. a muffled heart sound and thoracic dullness? were remarkable at auscultation and percussion, respectively. despite of aggressive medical treatment, the patient died after 48 hours of continued monitoring at hospital facility.? at necropsy most prominent findings were represented by hepatic-splenomegaly due to chronic passive congestion, related to bilateral congestive heart failure (pleural and peritoneal effusion and pulmonary edema). the presence of leishmania spp., amastigotes? in myocardial, spleen and lymph nodes tissues was revealed histologically, supporting? visceral leishmaniasis and infectious nature of this case report.
Caracterización de los sistemas de producción porcina en las principales regiones porcicolas colombianas Caracteriza o dos sistemas de produ o de suínos nas principais regi es suínas da Col mbia Characterization of pig farms in the main swine producing regions of Colombia
Carlos A Díaz,María N Rodríguez,Víctor J Vera,Gloria Ramírez
Revista Colombiana de Ciencias Pecuarias , 2011,
Abstract: El presente estudio tuvo como objeto caracterizar productivamente las granjas porcícolas colombianas de producción intensiva con más de 200 hembras en el pie de cría en las tres regiones con mayor influencia sobre la producción nacional lo cual representó el 62% del inventario nacional de madres. Se seleccionó aleatoriamente una muestra de 67 granjas con un nivel de confianza del 95%, una precisión del 10% y una variabilidad del 50%. Se aplicó una encuesta para estimar los principales indicadores sanitarios y de productividad en cada una de las etapas de producción: aclimatización, cría, precebo y ceba. Se establecieron las diferencias de los indicadores entre las regiones evaluadas (p<0.05) y se obtuvo una aproximación al desempe o productivo de las granjas identificando las fortalezas y debilidades de los sistemas en las regiones estudiadas. En promedio se estimó que las granjas tienen una tasa de parición del 87.6%, un promedio de 11.7 lechones nacidos totales, 10.8 lechones nacidos vivos y 10 lechones destetos por cerda; producen 22.3 lechones por cerda al a o y sacrifican animales de 102 kg de peso con 166.1 días al sacrificio en promedio. Los resultados obtenidos demostraron que los indicadores de competitividad son similares a los reportados en otros países e inclusive superiores, siendo importante considerar que la porcicultura colombiana está en capacidad de disminuir costos de producción asociados al incremento en el número de cerdos y kilogramos producidos por cerda al a o. Este estudo teve como objectivo caracterizar produtivamente as empresas suínas com mais de e 200 fêmeas reprodutoras em três regi es com maior influência nacional, que representaram 62% do inventário nacional das m es. Foi seleccionada aleatoreamente uma amostra de 67 granjas com um nível de confian a de 95%, uma precis o de 10% e uma variabilidade de 50%. Um inquérito foi utilizado para estimar indicadores de saúde e produtividade em todas as fases de produ o: aclimata o, cria, reprodu o, pré engorda e engorda. Foram encontradas diferencias entre granjas nos indicadores entre as regi es avaliadas (p<0.05) e obteve-se uma aproxima o do desempenho produtivo das granjas identificando-se os pontos fortes e fracos dos sistemas nas regi es estudadas. Em média as granjas agrícolas apresentaram uma taxa de natalidade do 87.6%, 11.7 leit es nascidos totais, 10.8 leit es nascidos vivos e 10 leit es desmamados por porca, produzidos 22.3 leit es por porca por ano e o abate foi de 102 kg com 166.1 dias. Os resultados mostraram que os indicadores da competitividade s o semelhantes a
Leishmaniasis visceral en un canino Visceral Leishmaniasis in a Dog
Eduardo E Zabala,Oneyda J Ramírez,Víctor Bermúdez
Revista de la Facultad de Ciencias Veterinarias , 2005,
Abstract: La leishmaniasis visceral es una enfermedad infecciosa y zoonótica distribuida mundialmente, que afecta al hombre, animales domésticos y silvestres. Su agente etiológico es un protozoario difásico del género Leishmania, cuyas especies difieren geográficamente en el Viejo y Nuevo Mundo, siendo transmitidos por vectores artrópodos de los géneros Phlebotomus y Lutzomyia en dichas áreas geográficas, respectivamente. En América Central y del Sur la Leishmania chagasi del complejo donovani, es causante de la leishmaniasis visceral, estando demostrada la positividad en el estado Aragua por estudios de seroprevalencia en la población canina autóctona. Un paciente canino macho, de raza Bóxer, de cuatro meses de edad se presentó con historia clínica de dificultad respiratoria e intolerancia al ejercicio de inicio agudo. Al examen físico se evidenció hipertermia y linfoadenomegalia generalizada; el ritmo y frecuencia cardiaca se encontraron alterados por disrritmias y taquicardia marcada; los sonidos cardiacos se apreciaron disminuidos de intensidad con matidez a la percusión torácica. La evolución fue desfavorable a pesar del tratamiento farmacológico, conllevando a la muerte del paciente en 48 horas de hospitalización con monitoreo contínuo. La necropsia reveló alteraciones macroscópicas de congestión pasiva crónica representados por hepato-esplenomegalia asociados a insuficiencia cardiaca congestiva bilateral (efusión pleuro-peritoneal y edema pulmonar). Histopatológicamente, se observó la presencia de amastigotes de Leishmania spp., en miocardio, bazo y nódulos linfáticos, soportando el diagnóstico etiológico de leishmaniasis visceral conjuntamente con la naturaleza infecciosa del cuadro clínico. Visceral leishmaniasis is a worldwide distributed infectious and zoonotic disease affecting people, domestic, and wildlife animals. It is caused by a diphasic protozoan of the genus Leishmania, involving distinct species that differs geographically between the Old and New World, and its arthropod vectors being from genuses Phlebotomus and Lutzomyia, responsible for transmission in those areas, respectively. Leishmania chagasi from the donovani complex, has been demonstrated as a cause for visceral leishmaniasis in Central and South America and its sero prevalence, among Aragua state canine population, has been shown by a field study. A four months old, male canine boxer was presented with concern for acute onset of respiratory distress and exercise intolerance. Physical examination revealed hyperthermia, generalized lymphoadenomegaly, severe dysrrittmia and ta
Espacio ampliado
Víctor Ramírez
Atenea , 2006,
Abstract:
Estudio de Infección Sistémica por Herpesvirus Complicada con Cryptosporidium spp., en un Delfín Manchado del Atlántico (Stenella frontalis. Cuvier, 1829)
Arias? León,Gabriela; Mariani di Lena,Miguel A; Cornejo Uzcátegui,Luis; Bermúdez García,Víctor; Ramírez Medina,Oneyda J;
Revista Científica , 2008,
Abstract: the present study was made, in the event of a young female dolphin of the specie stenella frontalis, that was found stranded in playa dorada, in boca de aroa, in the falcón state, the 07/30/02, in venezuela. she was kept in a facility for a period of three days, during this period of time, she was evaluated periodically whit not invasive technique, and morphometry data recollection. she died the 08/01/02 due to respiratory arrest, which caused a cardiac arrest. a macroscopic postmortem study was made, taking samples and keeping them in formaldehyde 10% for histopathology study of the following organs: heart, lungs, stomach, large intestine, liver, kidney and lesions of the skin with a fat layer, they were processed in the pathologic anatomy laboratory of the universidad central de venezuela. because of the results of the microscopic study, it was determined that the dolphin presented a systemic infection, because of a primary infection by herpesvirus spp., related with a secondary infection by cryptosporidium spp., which was complicated with stress due to the beaching. the bibliographic revue reports that the parasitosis by cryptosporidium spp. is not present to venezuela in the cetacean order, according to the compiled information about the studied parasites for this order. the skeleton is currently in the scientific museum of the biological station rancho grande - marnr.
Characterization of pig farms in the main swine producing regions of Colombia
Díaz,Carlos A; Rodríguez,María N; Vera,Víctor J; Ramírez,Gloria; Casas,Gloria A; Mogollón,José D;
Revista Colombiana de Ciencias Pecuarias , 2011,
Abstract: the goal of this study was to characterize intensive pig farms with inventories of 200 or more sows. farms were located in the three major swine rearing areas of colombia, representing 62% of the national total sow inventory. a random sample of 67 farms was evaluated, considering a 95% confidence level, 10% precision and 50% variability. a survey was applied to each farm, registering health and production indexes within each production stage, such as acclimatization, farrowing, weaning, and growing/finishing. index differences between regions were established (p<0.05) and herd performance was analyzed to identify strengths and weaknesses of the main colombian swine industry. herds in the evaluated regions had a 87.6% farrowing rate, with a total of 11.7 pigs born per litter, of which 10.8 were born alive; and 10 pigs were weaned per litter, with an average production of 22.3 pigs weaned per sow/year. the average slaughter age was 166.1 days with 102.2 kg per pig. indexes established in the present study were similar or higher compared to the ones reported for other countries. these data suggest that colombian swine producers still have great opportunities to increase profitability if production costs decrease and the number of pigs and the amount of pork produced per year is increased.
Imaginación, entendimiento y razón práctica en la Teoría Kantiana de lo sublime
García Ramírez,Víctor;
EPISTEME , 2008,
Abstract: the purpose of this paper is to show, in broad strokes, the relations of imagination, understanding and practical reason in kant?s doctrine of the sublime. to do this, we will divide our exposition in three parts: 1) differences between the feeling of beauty and sublime -according to imagination and understanding in each case. 2) kant?s ?mathematical? sublime and the limits of imagination and understanding. 3) kant?s ?dynamic? sublime and the relations with the practical reason.
La crítica de arte en Colombia: los primeros a?os
Quinche Ramírez,Víctor Alberto;
Historia Crítica , 2006,
Abstract: this article explores some of the first examples of art criticism in colombia. it traces the most relevant linguistic characteristics of art criticism, and shows that, in the second half of the 19th century, colombias first critics established a standard procedure by which to critique art. by reconstructing the polemics of 1886 and 1899, the article suggests that art critics shared a set of expectations about art that were silenced when andrés de santa maría organized, for the first time in the country, an exhibition of modern work. the articles thesis is that critics were forced to broaden their understanding of art in order to read this new type of work. even if this process was gradual, it points to the need to reevaluate how criticism was practiced at the time, since it has been judged as superficial and anecdotal, and therefore, of little interest. this article takes the opposing position, arguing for the need to reexamine the roots of the tradition of art criticism in colombia in order to avoid hasty readings and erroneous perceptions of our history.
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