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Search Results: 1 - 10 of 22951 matches for " ROBERTO URRUTIA "
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Observations and comments on the diatom Stephanodiscus minutulus (Kützing) Cleve & M?ller (Bacillariophyceae) found for the first time in Chile from bottom sediments collected in Lake Laja
Cruces,Fabiola; Rivera,Patricio; Urrutia,Roberto;
Gayana. Botánica , 2010, DOI: 10.4067/S0717-66432010000100002
Abstract: this study reports the presence of the diatom stephanodiscus minutulus (kützing) cleve & m?ller for the frst time in chilean continental waters; it is a taxon reported in many aquatic systems in europe and north america and there are only scanty records from south america (argentina). the species was found in a sedimentary profle collected from lake laja (andes mountains), central chile. the principal morphological features of s. minutulus are described, and comments about its relationship with other closely related taxa are given.
DETERMINACIóN DE LOS NIVELES BASALES DE METALES TRAZA EN SEDIMENTOS DE TRES LAGOS ANDINOS DE CHILE: LAGOS CHUNGARá, LAJA Y CASTOR
URRUTIA,ROBERTO; YEVENES,MARIELA; BARRA,RICARDO;
Boletín de la Sociedad Chilena de Química , 2002, DOI: 10.4067/S0366-16442002000400017
Abstract: the increase in trace metals concentrations (mercury, lead, cadmium, copper, chromium and zinc) in sediment cores from three andean lakes, located along a latitudinal gradient were determined (chungará, laja and castor lakes). samples were obtained in the deepest part of each lake, using a gravity corer model kayac. the sediment cores were vertically extruded at 1 cm intervals. trace metals analysis were performed through atomic absorption spectrophotometry (aas) with hydride generation technique for mercury flame atomic absorption (faa) for copper, chromium and zinc and graphite furnace for lead and cadmium. at the chungará lake the highest concentrations corresponding to hg and cd ranged from 0.038 -34; 0.12 μg/g and 0.048 - 0.210 μg/g, respectively. the highest concentrations at the laja lake corresponding to pb and cu, ranging from 6.7 - 14μg/g and 30 - 55 μg/g, respectively. at the castor lake only high concentrations of zn were detected reaching values of about 700 μg/g. results shown that only the chungará lake register an increase hg, pb and cd levels in the uppermost sections, showing enrichments factors about two times higher than the deepest sections. the laja lake shown a general trend of lower levels of most trace elements analyzed with the exception of zn showing higher levels in the uppermost section of the core. finally, the castor lake showed a increase of pb and cd levels upward the core, but the other metals didn?t show a clear trend. the increase in trace elements content of the chungará lake sediments is attributed to both local and regional pollution factors and are very similar to enrichments found in highland lakes in the northern hemisphere.
Abordaje de la epilepsia en la infancia.: Parte I
álvarez Fumero,Roberto; Valdés Urrutia,Lourdes;
Revista Cubana de Medicina General Integral , 1997,
Abstract: some of the considerations that should be taken into account by family physicians, pediatricians and neurologists in the comprehensive management of children with epilepsy are exposed. emphasis is made on the important information obtained from the anamnesis and from an exhaustive physical and neurological examination. the value of the examination of the fundus oculi, the skin and its adnexa is stressed. the advantages, disadvantages and indications of the images studies are shown, encouraging their more rational use. a warning is given on the rutinary use of hematic biometry studies, metabolic tests in urine and cerebrospinal examination in the diagnosis of epilepsy. the latest advances of cybernetics applied to neurology are also mentioned. the multidisciplinary evaluation of these children is considered as useful.
Observations and comments on the diatom Stephanodiscus minutulus (Kützing) Cleve & M ller (Bacillariophyceae) found for the first time in Chile from bottom sediments collected in Lake Laja Observaciones y comentarios acerca de la diatomea Stephanodiscus minutulus (Kützing) Cleve & M ller (Bacillariophyceae) encontrada por primera vez en Chile en sedimentos recolectados en el Lago Laja
Fabiola Cruces,Patricio Rivera,Roberto Urrutia
Gayana. Botanica , 2010,
Abstract: This study reports the presence of the diatom Stephanodiscus minutulus (Kützing) Cleve & M ller for the frst time in Chilean continental waters; it is a taxon reported in many aquatic systems in Europe and North America and there are only scanty records from South America (Argentina). The species was found in a sedimentary profle collected from Lake Laja (Andes Mountains), Central Chile. The principal morphological features of S. minutulus are described, and comments about its relationship with other closely related taxa are given. En este estudio se se ala la presencia de la diatomea Stephanodiscus minutulus (Kützing) Cleve & M ller por primera vez para aguas continentales de Chile; es un taxón muy común en diversos sistemas acuáticos de Europa y Norteamérica, y para Sudamérica sólo existen escasos registros en Argentina. La especie fue encontrada en un perfl sedimentario colectado en el Lago Laja (Cordillera de los Andes), Chile central. Se describen las principales características morfológicas de S. minutulus y se entregan comentarios sobre su relación con otras especies cercanas.
Abordaje de la epilepsia en la infancia.: Parte I
Roberto álvarez Fumero,Lourdes Valdés Urrutia
Revista Cubana de Medicina General Integral , 1997,
Abstract: El presente artículo cumple el objetivo de exponer algunas consideraciones que deben tener en cuenta los médicos de la familia, pediatras y neurólogos, en el manejo integral del ni o con epilepsia. Insistimos en la importante información que aporta la anamnesis y la realización de un exhaustivo examen físico neurológico. Resaltamos el valor del examen del fondo de ojo y de la piel y sus anexos. Mostramos las ventajas, desventajas e indicaciones de los estudios imagenológicos, exhortando a su utilización más racional. Alertamos sobre el uso rutinario de los estudios de biometría hemática, pruebas metabólicas en orina y examen del líquido cefalorraquídeo, en el diagnóstico de la epilepsia. Mencionamos los recientes avances de la cibernética aplicada a la neurología. Consideramos útil la valoración multidisciplinaria de estos ni os. Some of the considerations that should be taken into account by family physicians, pediatricians and neurologists in the comprehensive management of children with epilepsy are exposed. Emphasis is made on the important information obtained from the anamnesis and from an exhaustive physical and neurological examination. The value of the examination of the fundus oculi, the skin and its adnexa is stressed. The advantages, disadvantages and indications of the images studies are shown, encouraging their more rational use. A warning is given on the rutinary use of hematic biometry studies, metabolic tests in urine and cerebrospinal examination in the diagnosis of epilepsy. The latest advances of cybernetics applied to neurology are also mentioned. The multidisciplinary evaluation of these children is considered as useful.
Ambiente y territorio en el proyecto costanera del río Bíobío
María Dolores Mu?oz,Roberto Urrutia
Urbano , 2000,
Abstract:
DETERMINACIóN DE LOS NIVELES BASALES DE METALES TRAZA EN SEDIMENTOS DE TRES LAGOS ANDINOS DE CHILE: LAGOS CHUNGARá, LAJA Y CASTOR
ROBERTO URRUTIA,MARIELA YEVENES,RICARDO BARRA
Boletín de la Sociedad Chilena de Química , 2002,
Abstract: Se determinó el incremento de los metales mercurio, plomo, cadmio, cobre, cromo y zinc en la columna de sedimento de tres lagos andinos (Lagos Chungará, Laja y Castor). Las muestras de sedimento fueron obtenidas con un muestreador de gravedad modelo Kayak y seccionadas a intervalos de 1 cm. El análisis fue realizado por Espectrofotometría de Absorción Atómica (EAA), con técnicas de generación de hidruros para mercurio, llama (EAA-Llama) para cobre, cromo y zinc y horno de gráfito (EAA-HG) para plomo y cadmio. En el lago Chungará, el Hg y Cd presentaron las mayores concentraciones, variando entre 0.038 - 0.12 m g/g y 0.048 0.210 m g/g, respectivamente. En el lago Laja las mayores concentraciones correspondieron a Pb y Cu, fluctuando entre 6.7 -34; 14 m g/g y 30 -34; 55 m g/g, respectivamente. En el lago Castor, solamente el Zn mostró altas concentraciones, alcanzando valores de 700 m g/g. Los resultados muestranque sólo el lago Chungará presentó un enriquecimiento superficial de Hg, Pb y Cd, con concentraciones dos veces más altas que los estratos profundos. En el lago Laja se observó una tendencia a la disminución de la concentración de los metales analizados, exceptuando el Zn que registró un aumento en los centímetros superficiales. El lago Castor, presentó un aumento en la concentración de Pb y Cd hacia la superficie, el resto de los metales no mostró una tendencia clara. El aumento de metales pesados detectados en los niveles superficiales de los sedimentos del lago Chungará, es atribuido tanto a contaminación local como regional, siendo similares a enriquecimientos registrados en lagos de altura del hemisferio norte. The increase in trace metals concentrations (mercury, lead, cadmium, copper, chromium and zinc) in sediment cores from three Andean lakes, located along a latitudinal gradient were determined (Chungará, Laja and Castor lakes). Samples were obtained in the deepest part of each lake, using a gravity corer model Kayac. The sediment cores were vertically extruded at 1 cm intervals. Trace metals analysis were performed through Atomic Absorption Spectrophotometry (AAS) with hydride generation technique for mercury Flame Atomic Absorption (FAA) for Copper, Chromium and Zinc and graphite furnace for lead and cadmium. At the Chungará lake the highest concentrations corresponding to Hg and Cd ranged from 0.038 -34; 0.12 μg/g and 0.048 - 0.210 μg/g, respectively. The highest concentrations at the Laja lake corresponding to Pb and Cu, ranging from 6.7 - 14μg/g and 30 - 55 μg/g, respectively. At the Castor Lake only high concentrations of Zn were
Construyendo puentes entre investigación y políticas para la extensión de la protección social en salud en América Latina y el Caribe: una estrategia de cooperación conjunta
Bazzani, Roberto;Levcovitz, Eduardo;Urrutia, Soledad;Zarowsky, Christina;
Cadernos de Saúde Pública , 2006, DOI: 10.1590/S0102-311X2006001300020
Abstract: the pan american health organization (paho) and international development research centre (idrc) have promoted a joint initiative to design, implement, and evaluate innovative strategies for the extension of social protection in health (sph) in latin america and the caribbean (lac), involving active partnership between researchers and research users. this initiative was based on a previous review of research on health sector reforms and the recommendations of the workshop on "health sector reforms in the americas: strengthening the links between research and policy" (montreal, canada, 2001). in its first phase, the initiative supported the development of proposals aiming to extend sph, elaborated jointly by researchers and decision-makers. in the second phase, the implementation of five of these proposals was supported in order to promote the development of new sph strategies and new stakeholder interaction models. in this edition of the journal, the process of linking researchers and decision-makers will be analyzed in the context of the five projects supported by this initiative.
Comparación ambiental, mediante registros sedimentarios, entre las condiciones prehispánicas y actuales de un sistema lacustre
CISTERNAS,MARCO; TORRES,LAURA; URRUTIA,ROBERTO; ARANEDA,ALBERTO; PARRA,OSCAR;
Revista chilena de historia natural , 2000, DOI: 10.4067/S0716-078X2000000100014
Abstract: two moments of the environmental history of san pedro lacustrine system are compared through sedimentary, pollen and diatom records. the first one corresponds to the pre-hispanic period, representing the pristine conditions or background of the system. the second period, more recently, represents the human disturbance conditions during the late ten years. to achieve the above mentioned, sediment cores were collected from the bottom of two lakes that conform the san pedro lacustrine system (laguna grande and chica). chronological (c14), pollen and diatom analysis of superior and inferior layers of the cores were carried out. the results indicate that the san pedro lacustrine system has undergone drastic changes since spanish settlement. evolving from a natural vegetation, predominantly native, to an intense pressure of forestry use. in the same way, the qualitative water state presents a variation in its trophic features, showing a evolution from oligotrophic to eutrophic waters in laguna grande and from oligotrophic to mesotrophic in laguna chica. finally, it is suggested the incorporation of sedimentary records analysis in the study of environmental impact and management of lakes. in this way, it will be possible to know the background (the existing pre-hispanic conditions) and the response of aquatic ecosystem to the human influences
Paleolimnological studies of Laguna Chica of San Pedro (VIII Region): Diatoms, hydrocarbons and fatty acid records Estudio Paleolimnológico de Laguna Chica de San Pedro (VIII Región): Diatomeas, hidrocarburos y ácidos grasos
ROBERTO URRUTIA,SABBE KOEN,FABIOLA CRUCES,KARLA POZO
Revista chilena de historia natural , 2000,
Abstract: Diatom, hydrocarbons and fatty acid sedimentary records were used for reconstructing the recent (last 150 years) palaeolimnological history of Laguna Chica of San Pedro (Concepción, VIII Región, Chile). Cluster analyses (Constrained Incremental Sum of Squares) on the diatom data revealed three distinct periods. The first period (1883-1940's) showed a pronounced increase in sedimentation rate and a slight increase in organic matter accumulation. In this period, eutrophic species (Aulacoseira granulata and Staurosira construens) became increasingly dominant. From the 1940s until the 1970s the diatom signal is more equivocal: after the initial decrease in the relative abundance of A. granulata and S. construens their numbers fluctuate without a clear pattern. Sedimentation rates strongly fluctuate in this period. From 1978 onwards eutrophic species are in decline while indicators of oligotrophic conditions, such as Cyclotella stelligera and Aulacoseira distans, become more abundant. This shift in the lake trophic status could not be attributed to a reduction in the nutrient load from the catchment and we hypothesize that the invasion of the lake by the submersed macrophyte Egeria densa has altered nutrient availability to the plankton communities. This is in agreement with the hydrocarbons and fatty acid analyses which demonstrate a shift in carbon number distributions from short chain alkanes and alkanoic acids (typical for microalgae) to long chain molecules (characteristic for higher plants) in the upper layers of the lake sediment Se realizó la reconstrucción histórica de los últimos 150 a os de Laguna Chica de San Pedro (Concepción, VIII Región, Chile), a través de la utilización de los restos de diatomeas, hidrocarburos y ácidos grasos contenidos en la columna de sedimento. El análisis estratigráfico de las diatomeas reveló la presencia de tres períodos diferentes. El primer período (1883-1940's), mostró un marcado aumento de las tasas de sedimentación y un leve aumento en la acumulación de materia orgánica; en este período se registra un incremento de las especies eutróficas (Aulacoseira granulata y Staurosira construens). Desde los a os cuarenta hasta la década del setenta el cambio en la comunidad de diatomeas fue más evidente y las tasas de sedimentación variaron fuertemente. A partir de 1978 disminuyen las especies eutróficas y aumentan las indicadoras de condiciones oligotróficas (Cyclotella stelligera y Aulacoseira distans). El cambio en el estado trófico del lago, no se atribuye a una reducción de los aportes de nutrientes desde la cuenca, si
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