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Search Results: 1 - 10 of 18393 matches for " Romero-Torres "
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EFECTO DE BORDE SOBRE EL PROCESO DE DESCOMPOSICIóN DE HOJARASCA EN BOSQUE NUBLADO
ROMERO-TORRES,MAURICIO; VARELA RAMíREZ,AMANDA;
Acta Biológica Colombiana , 2011,
Abstract: forest fragments are physically delimited by edges and encircled by a surrounding matrix. the interaction between these communities dissimilar in structure and composition is defined as the edge effect. this occurrence generates local abiotic and biotic changes altering soil ecosystem processes. to determine the existence of the effect on leaf litter decomposition and its control factors, two fragments of cloud forest in the southwest region of the bogotá savannah were selected. within each, two 64 m long transects were laid out bearing east and west from edge to center respectively, a leaf litter decomposition experiment of a 90 to 180 day duration was set up at seven distances measured from the starting point of each transect. the percentage of leaf litter moisture and decomposition, vegetation density, anamorphic fungi density and carbon:nitrogen ratio were estimated at each point. the maximum distance of the edge effect on the decomposition was determined, and the interaction between orientation, distance and the regulating factors of the decomposition process were ascertained. the results established an effect of the cardinal orientation of the edge on the decomposition and its regulating factors. marked edge effects on leaf litter moisture extending up to 7 m and up to 30 m on vegetation density were displayedin eastern border areas. in forest areas, decomposition was regulated by leaf litter moisture and its c:n ratio. the limited penetration of edge effect suggests minor effects regarding nutrient cycles and provides justification and additional value to the use of small fragments.
Factores de calidad del servicio en el transporte público de pasajeros: estudio de caso de la ciudad de Toluca, México
óscar Sánchez-Flores,Javier Romero-Torres
Economía, sociedad y territorio , 2010,
Abstract: En este artículo se identifican, ponderan y valoran los factores que intervienen en la percepción de la calidad de servicio del transporte público en un corredor urbano que se caracteriza por una gestión delegada con tarifa fija y competencia en calidad. Mediante un modelo logit con especificación lineal de la función de utilidad, se estiman los coeficientes de cada factor de calidad de servicio para diferentes segmentos y estratos de la población. Los resultados de la estimación econométrica determinan la importancia, peso y valor de cada factor en términos de utilidad. De esta manera se obtiene que los factores principales que determinan la calidad del servicio son: el estado físico de los autobuses, la forma de manejo del conductor, la tarifa (costo del viaje), el tiempo que está dentro del autobús (tiempo de viaje) y el trato al usuario.
EFECTO DE BORDE SOBRE EL PROCESO DE DESCOMPOSICIóN DE HOJARASCA EN BOSQUE NUBLADO
Romero-Torres Mauricio,Varela Ramírez Amanda
Acta Biológica Colombiana , 2011,
Abstract: Los fragmentos de bosque son delimitados por bordes y rodeados de matriz circundante. La interacción entre estas comunidades disimiles en estructura y composición, se define como efecto de borde. Este fenómeno genera localmente cambios abióticos y bióticos alterando procesos ecosistémicos del suelo. Para determinar la existencia de este efecto sobre la descomposición de hojarasca y sus factores de control, se seleccionaron dos fragmentos de bosque nublado en la Sabana de Bogotá. Desde los bordes se trazaron transectos con longitud de 64 m y dirección oriente-interior y occidente-interior, donde se dispuso un experimento de descomposición de hojarasca con duración de 90 y 180 días. Allí se estimó el porcentaje de humedad y descomposición de hojarasca, densidad de vegetación, densidad de hongos anamorfos y relación Carbono:Nitrógeno. Se determinó la distancia máxima del efecto de borde y la interacción entre el tiempo de descomposición, orientación y distancia, y se establecieron los factores reguladores de la descomposición. Los resultados mostraron un efecto de la orientación cardinal del borde sobre la descomposición y sobre sus factores reguladores cómo humedad y calidad química. En las zonas de borde oriental se presentó un marcado efecto de borde sobre la humedad de hojarasca hasta los 7 m y sobre la densidad de vegetación hasta los 30 m. En los fragmentos de bosque la descomposición fue regulada por la humedad y relación C:N de la hojarasca. La poca penetración del borde sugiere efectos menores sobre el ciclaje de nutrientes, proporcionando un valor adicional a la conservación de fragmentos peque os.
A Proposal to Classify Latinamerican Scientific Journals using Citation Indicators: Case Study in Colombia
Mauricio Romero-Torres,Maria Alejandra Tejada,Alberto Acosta
Computer Science , 2011,
Abstract: Colombian scientific journals are poorly represented in international digital libraries; however, through Google Scholar (GS) it is possible to determine their use by the community. Between the years of 2003 and 2007 a classification of 185 Colombian journals indexed in the Colombian National Bibliographical Index (IBNP) was performed using the information provided by GS, basing categorization on size indicators, indexation and citation. The indicators were analyzed by grouping the journals in two general areas: sciences and social sciences. In each area, the indicators provided by the digital libraries Scopus, Redalyc and Scielo were compared. Additionally, the indicators provided by IBNP journals categories (A1, A2, B and C) were also compared. The sciences and social sciences had a similar pattern in their indicators. The existence of positive correlations was established between some indicators and they predicted that the number of citations per journal in GS and the h index depends on its visibility in GS and Scopus. We put forward that the current IBNP categories (A1, A2, B or C) faintly reflect the use of journals by the community and we propose a classification based on the h index as an infometric indicator, which reflects not only its visibility in Google Scholar, but also its inclusion in certain international digital libraries, particularly Scopus. Our results may be applied to the creation of public policies regarding science and technology in Colombia and in developing countries.
Ranking de revistas científicas en Latinoamérica mediante el índice h: estudio de caso Colombia
Romero-Torres, Mauricio,Acosta-Moreno, Luis Alberto,Tejada-Gómez, María Alejandra
Revista Espa?ola de Documentación Científica , 2013,
Abstract: The future of scientific journals in Latin America is uncertain. The inability to calculate bibliometric indicators to classify and homologate journals according to globally-used quartiles reduces journal visibility. For instance, Colombian journals classified in the National Bibliographic Database Publindex (BBNP) under categories A1, A2, B and C, have low rates of indexing in international databases, such as Web of Science or Scopus, thus limiting the estimation of bibliometric indicators for comparison at an international level. In this case study, articles published between 2003 and 2007 were taken from 211 journals selected from the BBNP- 2008. Using Google Scholar, Publish or Perish software and the Scopus database, impact and productivity indicators were quantified and compared creating a regional ranking (Q1-Q4). They were subsequently homologated internationally with the Scimago Journal Ranking (SJR). The h index proved the best indicator to generate the ranking of 170 Colombian journals based on quartiles (Q1-Q4) able to be homologated with SJR quartiles. We propose this methodology for classifying and homologating Latin American journals that are not indexed internationally, as a useful tool for publishers, publishing houses, information agencies and public policy decision-makers concerning education, science and technology, both regionally and globally. El futuro de las revistas científicas en Latinoamérica es incierto. La incapacidad de calcular indicadores bibliométricos útiles para clasificarlas y homologarlas con cuartiles de referencia mundial reducen su visibilidad. Por ejemplo, las revistas colombianas clasificadas en la Base Bibliográfica Nacional Publindex (BBNP) bajo las categorías A1, A2, B y C, poseen baja indexación en bases de datos internacionales como Web of Science o Scopus, limitando la estimación de indicadores bibliométricos para su comparación a nivel internacional. Como estudio de caso se seleccionaron 211 revistas de la BBNP-2008, tomando artículos publicados entre 2003 y 2007. Utilizando Google Académico, el software Publish or Perish y la base de datos Scopus, se cuantificaron y compararon indicadores de productividad e impacto para construir un ranking local (Q1-Q4) y realizar una homologación internacional con Scimago Journal Rank (SJR). El índice h resultó el mejor indicador para generar un ranking basado en cuartiles (Q1-Q4) de 170 revistas colombianas, homologables con cuartiles de SJR. Se propone esta metodología para clasificar y homologar las revistas latinoamericanas no indexadas, como herramienta útil para
Epidemiología molecular de las tuberculosis bovina y humana en una zona endémica de Querétaro, México
Pérez-Guerrero,Laura; Milián-Suazo,Feliciano; Arriaga-Díaz,Camila; Romero-Torres,Cecilia; Escartín-Chávez,Minerva;
Salud Pública de México , 2008, DOI: 10.1590/S0036-36342008000400006
Abstract: objective: the purpose of the study was to determine the role of bovine tb in cases of human tb. material and methods: two-hundred and fifty-five samples from symptomatic patients were included in the study. all samples were cultured in stonebrink and low?nstein-jensen media and analyzed using a nested pcrmpb70. the molecular analysis was performed by spoligotyping. results: from 255 samples, 74 were pcr-positive and 20 were culture-positive. from 94 samples positive to pcr or to isolation, 66 (70%) showed a spoligotype compatible with m. tuberculosis, and 13 (13.8%) with m. bovis. four fingerprints of m. bovis from humans were identical to the fingerprints of m. bovis from cattle in the same region. conclusions: our study shows that m. bovis plays an important role in the epidemiology of tb in humans and that tb in cattle represents a risk to public health.
Dosis mínima infectante de la fase micelial de Histoplasma capsulatum var. capsulatum, en ratones Balb/c
Torres,Joel; Romero,Hilda;
Revista de la Sociedad Venezolana de Microbiología , 2011,
Abstract: the objective was to determine the histoplasma capsulatum minimal infective dose (mid) by the inoculation of the mycelium phase in balb/c mice, with the purpose of contributing useful alternatives for the future application of fungal inoculums which facilitate the reproduction of the disease. several inoculums with 50, 75 and 94% transmittance (t) were prepared with a mixture of standardized suspensions from five isolations of the fungus, determining colony forming units/ml (cfu/ml) for each inoculum. three groups of 10 mice each, identified as g2, g3 and g4, were injected intraperitoneally with 100 μl of each inoculum. another group (g1) was included as healthy control. all mice were observed during 15 days. the disease was determined by observation of the animals, and by histopathological and mycological examinations. the mid was 50% t (17.5 x 104 cfu/ml ) selected on basis of the presence of hepatosplenomegaly, nodules in liver and/or spleen, and the percentage of recovery of fungi from subcultures. the results showed the reproduction of the disease in absence of deaths during the 15-day observation period
La escuela: entre el panóptico y la expedición urbana. Un marco para entender la pedagogía del agua en Bogotá
Julián David Romero Torres
Perfiles educativos , 2012,
Abstract: El estudio de la relación entre la escuela y la ciudad, sus implicaciones y el análisis de un discurso pedagógico en particular, que se preocupa por la preservación de los recursos naturales, la apropiación y el cuidado del sistema hídrico que está gravemente afectado, nos da las herramientas para analizar el impacto que constituye una propuesta de trabajo que busca promover nuevas percepciones, tanto a nivel individual como colectivo, hacia los cuerpos de agua y hacia el sistema hídrico. Este análisis tiene el propósito de dilucidar la importancia que programas como el de Pedagogía del Agua del Acueducto de Bogotá tienen en la generación de nuevos conocimientos, percepciones y actitudes.
El papel de la Sociedad Civil en la construcción de sistemas de salud equitativos
Vega Romero,Román; Torres Tovar,Mauricio;
Revista Cubana de Salud Pública , 2011, DOI: 10.1590/S0864-34662011000200008
Abstract: objective to provide evidence on the contribution of the civil society to the building of equitable health systems. data source several sources of information, search engines and databases were reviewed, such as goggle, un websites, the training and research support center, the southern africa regional network for equity in health, the civil society initiative by who, paho and public and private initiatives. the reviewed articles included research files, published peer-reviewed articles, gray literature, systematic reviews of specialized documents and reports on this topic. some of the key words were: health system-centered persons, equity and public policies, non-governmental organizations and intersectoral actions in health. data synthesis evidence showed that the civil society has contributed to the building of equitable health systems due to its subject and population-centered approach, the intersectoral action in favor of health and the empowerment and social mobilization. however, a lot of actions taken by the civil society organizations have favored the global and national policies that defen private market interests. in some cases, these actions have been targeted, minimal, biased or insignificant with respect to the challenges of health equity or they have served to hide the non-existence of commitment by the governments to the poor, the vulnerable and the excluded people. conclusions it is required to have a general ethical and political perspective directed to recognize and strenghten the role of the civil society to improve health and reduce health inequities.
El papel de la Sociedad Civil en la construcción de sistemas de salud equitativos The role of the civil society in the building of equitable health systems
Román Vega Romero,Mauricio Torres Tovar
Revista Cubana de Salud Pública , 2011,
Abstract: Objetivo Proveer evidencias sobre la contribución de la Sociedad Civil a la construcción de sistemas de salud equitativos. Fuente de datos Se revisaron diferentes fuentes de información, buscadores y bases de datos, entre ellas, Google, los sitos Web de las Naciones Unidas, el Training and Research Support Centre, The Southern Africa Regional Network for Equity in Health, la Iniciativa sobre la Sociedad Civil de la OMS, la OPS e iniciativas públicas y privadas. Los artículos que se revisaron incluyeron archivos de investigación, artículos publicados con revisión de pares, literatura gris, revisiones sistemáticas de documentos e informes especializados sobre el tema. Algunas de las las palabras clave empleadas fueron: personas centradas en sistemas de salud, equidad y políticas públicas, organizaciones no gubernamentales y sistemas de salud, organizaciones no gubernamentales y acción intersectorial en salud. Síntesis de los datos Las evidencias muestran que la Sociedad Civil ha podido contribuir a constituir sistemas de salud equitativos por su enfoque centrado en las personas y en la población, en la acción intersectorial por la salud y en el empoderamiento y movilización social. Sin embargo, muchas acciones de organizaciones de la Sociedad Civil también han sido funcionales a las políticas globales y nacionales que defienden intereses privados del mercado. Tales acciones en algunos casos han sido focalizadas, mínimas, sesgadas e insignificantes en relación con los desafíos de la equidad en salud, o han servido para ocultar la falta de compromiso de los gobiernos con los pobres, vulnerables y excluidos. Conclusiones Se hace necesaria una perspectiva ética y política general orientada a reconocer y fortalecer el papel de la Sociedad Civil para mejorar la salud y reducir las inequidades en salud. Objective To provide evidence on the contribution of the civil society to the building of equitable health systems. Data source Several sources of information, search engines and databases were reviewed, such as Goggle, UN websites, the Training and Research Support Center, the Southern Africa Regional Network for Equity in Health, The Civil Society Initiative by WHO, PAHO and Public and Private Initiatives. The reviewed articles included research files, published peer-reviewed articles, gray literature, systematic reviews of specialized documents and reports on this topic. Some of the key words were: health system-centered persons, equity and public policies, non-governmental organizations and intersectoral actions in health. Data synthesis Evidence showed that
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