Contribución del programa 'Nieves y glaciares tropicales' (NGT al conocimiento de la variabilidad climática en los Andes

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1998-01-01

Full Text Available CONTRIBUTION DU PROGRAMME “NEIGES ET GLACIERS TROPICAUX” (NGT À LA CONNAISSANCE DE LA VARIABILITÉ CLIMATIQUE DANS LES ANDES. Les glaciers tropicaux sont d’excellents indicateurs de l’évolution du climat à cause de leur extrême sensibilité aux variations des paramètres météorologiques tels que les températures, la radiation, les précipitations etc. (Pouyaud et al., 1995. Ils ont enregistré les implications climatiques des phénomènes El Niño (ENSO et ils peuvent donner des informations précieuses sur leur fréquence et leur amplitude. Ce sont aussi des objets hydrologiques et les populations andines exploitent leurs ressources. Ils peuvent évoluer très rapidement. Le recul actuel, accéléré et généralisé des glaciers des Andes centrales a des conséquences hydrologiques et peut constituer des risques naturels. L’ORSTOM et ses partenaires scientifiques andins ont mis en route depuis 1991 un vaste programme de suivi dans l’ensemble des Andes tropicales. On évalue les résultats de ce programme jusqu’à la fin 1997. Los glaciares tropicales son excelentes indicadores de la evolución del clima por su extrema sensibilidad a las variaciones de los parámetros meteorológicos como las temperaturas, la radiación y las precipitaciones, etc. (Pouyaud et al., 1995. Bajo este concepto, han registrado las implicaciones climáticas de los fenómenos El Niño-Oscilación del Sur (ENSO y pueden proporcionar valiosas informaciones sobre su frecuencia y su magnitud. Son también objetos hidrológicos, cuyos recursos son aprovechados por las sociedades andinas, susceptibles de evoluciones futuras muy rápidas. El actual retroceso, generalizado y acelerado, de los glaciares de los Andes centrales y sus consecuencias en términos de hidrología o de riesgos naturales, condujeron al ORSTOM y sus contrapartes científicas andinas a lanzar desde 1991 un amplio programa de monitoreo de estos glaciares en el conjunto de los Andes tropicales

Arquitectura precerámica en la cordillera de los Andes, Piruru frene a la diversidad de los datos

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Elisabeth Bonnier

1988-12-01

Full Text Available Los datos sobre la arquitectura precerámica en la cordilleraandina provienen de cinco sitios: La Galgada, Piruru, Huaricoto, Shillacotoy Kotosh. Contexto arqueológico y rasgos arquitectónicos específicos permitenidentificar la función ceremonial de esta arquitectura. La descripciónde las construcciones religiosas pone en evidencia un conjunto pertinente decaracteres comunes. El espacio ceremonial, construido y sin construir, se articulaalrededor del doble elemento arquitectónico fundamental, el fogón yel piso. Para analizar el piso a dos niveles, dos neologismos, pericausto y epicaustohan sido creados. El análisis arquitectónico muestra que el piso es elespacio sagrado por excelencia. Los fechados 14C de los sitios estudiadosdestacan la larga duración del Precerámico Final con arquitectura. A la luz delos últimos trabajos en Piruru y de los cambios arquitectónicos perceptiblesen este sitio, la hipótesis, formulada a principios de este decenio, sobre ·taexistencia de una tradición religiosa única propia de los Andes Centrales, seestá reconsiderando.

Steady-state exhumation pattern in the central Andes SE Peru

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Ruiz, G.M.H.; Carlotto, V.; van Heiningen, P.S.; Andriessen, P.A.M.

2009-01-01

The Western Cordillera of SE Peru is part of the Central Andes and is situated to the west of the Eastern Andes from which it is separated by the northern termination of the Altiplano - the Inter-Andean Valley. It is a volcanic-volcano-detrital chain that developed in the Palaeogene, and is

Un réseau d'observation des glaciers dans les Andes tropicales

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1995-01-01

Full Text Available Par leur grande sensibilité au changement climatique, les glaciers tropicaux sont d’excellents indicateurs de l’évolution du climat et, en même temps, des objets hydrologiques susceptibles d’évoluer rapidement dans le futur. On montre que l’actuel recul accéléré des glaciers dans les Andes centrales et les conséquences qu’il peut avoir en matière hydrologique et de risques naturels rendent nécessaire un programme de surveillance de ces glaciers au niveau de toute la chaîne, ce que l’ORSTOM contribue à faire depuis 1991. UNA RED DE OBSERVACIÓN DE LOS GLACIARES EN LOS ANDES TROPICALES. Por su gran sensibilidad al cambio climático, los glaciares tropicales son excelentes indicadores de la evolución del clima, así como objectos hidrológicos susceptibles de una evolución rápida en el futuro. Considerando el actual retroceso acelerado de los glaciares en los Andes centrales y las consecuencias que puede tener a nivel hidrológico así como en el campo de los riesgos naturales, es necesario un programa de monitoreo de los glaciares a nivel de toda la cordillera, que es lo que ORSTOM contribuye a hacer desde 1991. A GLACIER MONITORING NETWORK IN THE TROPICAL ANDES. The high sensibility of Tropical glaciers to climatic forcing make it possible to use them as reliable indicators of climate evolution, as well as hydrological systems which could change rapidly in the future. Considering the present increase in glacier retreat in central Andes and the consequences induced by this evolution on water resources and natural hazards, a monitoring program at a large scale appears to be highly desirable. This has been the objective of ORSTOM since 1991.

Memoria de los Andes, memoria de la naturaleza

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Usselmann, Pierre

2013-01-01

Hace más de 35 años, terminando su tesis (1965), OlivierDollfus destacó la importancia de los Andes, “inmenso ysuntuoso campo”, para futuras investigaciones. En ese entonces sus estudios trataban de la geomorfología; escribía que “una de sus razones de ser es justamente este vaivén constante entre la observación de los procesos actuales y el intento de explicación, es decir el análisis de las formas heredadas” (1964). Esta preocupación, esta noción de memoria de la naturaleza, complementaria ...

Las ignimbritas del complejo volcánico Coranzuli (Puna Argentina-Andes Centrales

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Martí, J.

1987-12-01

Full Text Available The Coranzulí is a large Upper Miocene volcanic complex located on a NE-SW and NW-SE regional faults intersection, at 66º 15' W 23º S, in the Northwest of Argentina in Jujuy province. It corresponds to one of four large volcanic complexes which represent the end of Transversal Volcanic Chaines in La Puna Argentina in the Central Andes. The volcanic activity was characterized by at least four separate ignimbrite eruptions which produced four different ignimbrite sheets. These are well welded, very crystal-rich, lithie poor ignimbrites and have a moderate to high pumice content. The total volume of the Coranzuli ignimbrites exeededs 650 Km3. Preliminary data indicate that the eruption oeeurred from a homogeneous magmatic chamber without zoning. The emplacement characteristics of the ignimbrites and the lack of basal or interbedded plinian fall deposits suggest that the eruptions developed quickly to massive proportions.El Coranzuli es uno de los grandes complejos volcánicos que representan el remate final de las Cadenas Volcánicas Transversales de la Puna Argentina, en los Andes Centrales. Se trata de un complejo volcánico del Mioceno superior situado a los 66º 15' W 23º S en el NW de Argentina en la provincia de Jujuy, en la intersección entre dos fallas regionales de dirección NE-SW y NW-SE, respectivamente. La actividad eruptiva se caracterizó por la existencia de, al menos, cuatro erupciones ignimbríticas que produjeron cuatro diferentes mantos ignimbríticos. Se trata de ignimbritas bien soldadas, muy ricas en cristales, pobre en fragmentos líticos y que presentan un contenido en fragmentos pumíticos de moderado a alto. El volumen total que representan estas ignimbritas supera los 650 km3. Los datos preliminares indican que el magma juvenil deriva de una cámara magmática homogénea no zonada. Las características de emplazamiento de estas ignimbritas, así como la falta de depósitos plinianos de caída en la base o

Nurse effect in seedling establishment: facilitation and tolerance to damage in the Andes of central Chile Efecto nodriza en el establecimiento de plántulas: facilitación y tolerancia al daño en los Andes de Chile central

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IAN S ACUÑA-RODRÍGUEZ

2006-09-01

ás relevante en ambientes estresantes. Este efecto sería particularmente importante durante el periodo de establecimiento de las plántulas debido a su alta vulnerabilidad a factores bióticos y abióticos como herbivoría y desecación. La tolerancia a la herbivoría evidencia la capacidad de las plantas de recrecer y reproducirse después del daño, pero esta capacidad es recurso-dependiente. En los Andes de Chile central, la planta en cojín Laretia acaulis (Apiaceae atenúa el efecto del estrés ambiental, aumentando la supervivencia de diversas especies de plantas asociadas. Proponemos que las plántulas que se encuentren creciendo dentro de los cojines de L. acaulis deberían evidenciar niveles mayores de tolerancia en relación a aquellas plántulas creciendo fuera de los cojines. Para probar esta hipótesis se llevó a cabo un experimento de campo con dos especies nativas perennes: Hordeum comosum (Poaceae y Haplopappus anthylloides (Asteraceae. Plántulas de ambas especies fueron sembradas dentro y fuera de los cojines de L. acaulis, y la mitad de ellas recibieron daño manual (50 % tejido foliar removido. En general, las plántulas que se encontraron creciendo dentro del cojín evidenciaron una mayor supervivencia independientemente del tratamiento de daño. A pesar de que la ubicación de las plántulas no afectó la respuesta en tolerancia por parte de H. anthylloides, sí afectó significativamente la tolerancia de H. comosum. Por lo tanto, encontramos valores similares para la supervivencia de plántulas de H. comosum dentro de los cojines, pero la supervivencia de plántulas dañadas fuera de los cojines fue significativamente menor que la de plántulas control. Se pudo evidenciar la ocurrencia de efecto nodriza por parte de L. acaulis sobre el establecimiento de ambas especies y conjuntamente un aumento en la tolerancia al daño para H. comosum en este hábitat estresante

Finanzas de la Universidad de Los Andes

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Rosa Aura Casal de Altuve

2006-01-01

Full Text Available El objetivo primario de este artículo es el de fungir de base comparativa para otros estudios de países latinoamericanos que podrían estar considerando síntomas similares en el área de la investigación contable. El punto de partida lo representa un estudio de caso de los profesores del Departamento de Contabilidad y Finanzas de la Facultad de Ciencias Económicas y Sociales de la Universidad de los Andes. El artículo analiza la relación entre investigación y enseñanza y si el departamento está o no cumpliendo con sus objetivos. Un objetivo secundario consiste en la determinación de los posibles factores que han tenido una influencia significativa en el desempeño de la investigación y de la enseñanza por parte de los investigadores. Basándose en entrevistas y recolección directa de datos, se consideran las estrategias institucionales para fijar los objetivos de las actividades de investigación

Limitación de la conservación de variedades nativas por variedades mejoradas: Estudio de caso de la papa en los Andes centrales del Ecuador

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MSc. María Cecilia Dávila

2018-04-01

Full Text Available La conservación de la biodiversidad para la alimentación y la agricultura, es una actividad importante a nivel mundial para asegurar la seguridad alimentaria y nutricional, pero dicha actividad está siendo limitada por varios factores. Este estudio de caso analiza cómo la adopción de variedades mejoradas de papa limita la conservación de la diversidad de las variedades nativas a nivel de granja o chakra en seis comunidades indígenas en los Andes centrales ecuatorianos. Los resultados muestran que la adopción de variedades mejoradas ha desplazado una amplia gama de variedades locales tradicionales de los campos de agricultores que, junto con las condiciones socioeconómicas y ambientales que caracterizaron el sitio de estudio, han socavado la diversidad genética de variedades cultivadas de papa en las fincas. Palabras clave: Conservación en finca, diversidad de papa, variedades mejoradas, variedades nativas.

CARACTERIZACIÓN FÍSIOGRÁFICA DE LA PUNA DE SAJAMA, CORDILLERA OCCIDENTAL DE LOS ANDES (BOLIVIA

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Fernando Javier Santa Cecilia Mateos

2015-01-01

Full Text Available Este artículo aproxima a la realidad física de la cordillera Occidental de los Andes. Un espacio geográfico donde los caracteres geológicos relacionados con el vulcanismo adquieren una relevancia especial en la configuración del paisaje andino. Los nevados y llanuras intermedias o altiplanos, son los dos elementos que constituyen la imagen de la puna andina, un territorio situado por encima de los 4.000 metros, ámbito intermedio entre los valles húmedos o yungas y las más altas cumbres de los Andes. A la singularidad volcánica habría que añadir la relacionada con el modelado glaciar, los aspectos hidrográficos y la biogeografia en esta área. El artículo toma como ejemplo de estudio la puna de Sajama en eldepartamento de Oruro, en la frontera boliviano-chilena.Abstract. This article approaches the physical reality of the Western Cordillera of the Andes. A geographical space where characters related geological volcanism are of particular importance in shaping the landscape Andean. The intermediate plains or mountains and plateaus, are the two elements that make up the image of the Andean puna, an area located above 4,000 meters, the middle ground between Yungas wet valley and the highest peaks of the Andes. A volcanic uniqueness should add that related to glacier modeling, hydrographic aspects and biogeography in this area. The article uses the example of the highlands of Sajama study in thedepartment of Oruro in Bolivian-Chilean border.

CONSTRUCCIÓN DE SUBJETIVIDADES POLÍTICAS DE NIÑAS, NIÑOS Y JÓVENES, EN EL CONTEXTO DE LA EXPERIENCIA EDUCATIVA CAE, EN LOS ANDES CENTRALES DEL PERÚ:UN REFERENTE DE CONSTITUCIÓN SOCIOCULTURAL, SOCIOAMBIENTAL

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MARCO TULIO PEÑA

2013-07-01

Full Text Available El presente artículo es producto de los desarrollos investigativos y reflexivos de la experiencia educativa “Construcción de subjetividades políticas de niñas, niños y jóvenes quechuahablantes, en el contexto de la experiencia ‘Comunidades Andinas Educativas’ en los Andes centrales del Perú: un referente de educación alternativa”. Desarrollada entre los años 2008-2009 y 2012, con la participación integral de los actores que formaron parte de esta investigación en el distrito de Pucará, provincia de Huancayo, departamento de Junín, Andes centrales del Perú. El trabajo se presentó como tesis de la Maestría en Desarrollo Educativo y Social en el Centro Internacional de Educación y Desarrollo Humano (Cinde y la Universidad Pedagógica Nacional (Bogotá, Colombia, 2013. Desde el contexto de recuperación de la experiencia educativa, se buscó significar conocimientos en torno a la construcción de subjetividades políticas de niñas, niños y jóvenes andinos considerando su universo sociocultural y socioambiental, diverso y particularizado de las comunidades andinas quechuas. La investigación se enmarcó en la modalidad de la sistematización de experiencias educativas mediante el establecimiento de unidades categoriales interpretativas devenidas de los hitos o momentos centrales, referidas a los procesos de formación y constitución de Asociaciones Educativas Infantiles (AEI y de interpretación, para este caso en la formación de habilidades interculturales y de sostenibilidad medioambiental. Dicho trabajo develó aportes significativos relacionados con la educación comunitaria y alternativa en el aporte a los procesos de motivación y construcción de subjetividades Políticas de niñas, niños y jóvenes andinos, desde contexto sociocultural y socioambiental particularizado y diverso del universo y cosmovisión andina.

Geografía, café y prosperidad en los andes occidentales de Colombia

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Juan Barón

2011-07-01

Full Text Available Compuesta por los departamentos de Antioquia, Caldas, Quindío, Risaralda y Valle del Cauca, los Andes Occidentales ha sido por mucho años una de las regiones más prósperas de Colombia. Esta prosperidad se ha traducido en condiciones de vida e infraestructura superiores a las del resto del país. El éxito y bienestar que presentan hoy en día los Andes Occidentales están estrechamente ligados a la concentración de la producción de café, que se dio allí durante gran parte del siglo XX. El arraigo del café en la región no sólo se dio debido a que la geografía ofrecía las condiciones ideales para el cultivo, sino también a las instituciones cafeteras creadas para organizar la industria del café. A pesar de esta prosperidad, el constante descenso del precio internacional del café después del rompimiento del pacto de cuotas de producción en 1989, sumado al estancamiento de la industria manufacturera en algunos departamentos de la región, han afectado las economías departamentales menos diversificadas. Es así como la región de los Andes Occidentales Colombianos presenta las tasas de desempleo más altas del país, tasas que se han visto afectadas aún más con la crisis financiera internacional a través del menor flujo de remesas que los trabajadores oriundos de la región, y residentes en el exterior envían a sus familias.

El tarwi o chocho: una de las principales fuentes de proteína vegetal de las comunidades indígenas de los Andes Centrales

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Planchuelo, Ana M.

2005-01-01

Full Text Available El lupino andino (Lupinus mutabilis Sweet conocido también como tarwi o chocho, es una especie de leguminosa nativa de los Andes Centrales. Su domesticación se remonta a los principios de la cultura Nazca y desde ese entonces hasta la actualidad el cultivo está ampliamente difundido en las laderas montañosas y en los altos valles de Ecuador, Perú y Bolivia. La importancia del lupino para las comunidades andinas prehispánicas quedo documentada en pinturas de cerámicas y en tributos encontrados en tumbas de 100-150 años AC. Diversas técnicas de lavado y de mejoramiento vegetal fueron aplicadas desde la antigüedad para eliminar los alcaloides tóxicos que le confieren el sabor amargo a la planta y los granos. El tarwi, el maíz. los frijoles, los pseudocereales, quinoa y amaranto y la papa junto a otras raíces y tubérculos constituyen la comida básica de muchas culturas andinas. El objetivo de este trabajo fue determinar los componentes nutricionales de los granos del lupino andino para compararlos con los otros constituyentes de la dieta de las comunidades campesinas. Se analizaron por medio de técnicas fitoquímicas distintas variedades de tarwi. Se determinaron los contenidos de proteínas y grasas y los patrones de ácidos grasos. Los resultados muestran que la ingesta de lupinos, que provee un buen balance de proteínas y grasas en combinación con el maíz y los tubérculos, que aportan los hidratos de carbono, forman una dieta balanceada y de alto valor nutricional.

Las puntas y rejas prehispánicas de metal en los Andes y su continuidad hasta el presente

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2005-01-01

Full Text Available Les pointes et les socs préhispaniques en métal dans les Andes et leur continuité jusqu’à aujourd’hui Résumé: Cet article tente de montrer la continuité entre les instruments à usages multiples composés de pointes et des socs en cuivre arsenical insérés sur des manches en bois qui ont été élaborés à partir de 900 d. C. par les Sicán de Batán Grande, département de Lambayeque (Pérou, et certains instruments en acier utilisés actuellement dans les Andes du nord du Pérou et du sud de l’Équateur : les barretas, barretillas, barretones et les petites pelles. Il s’agit d’indiquer, sur la base d’informations ethnographiques, la relation entre ces instruments et les allachus, kituchis et chaquitacllas dont se servent les paysans des hautes terres du centre et du sud du Pérou, ceci dans le but de contribuer à l’élaboration d’une histoire de la technologie andine. Este artículo intenta, por un lado, mostrar la continuidad entre las herramientas multiusos elaboradas a partir de 900 d.C. por los sicanes de Batán Grande, departamento de Lambayeque (Perú, compuestas por puntas y rejas de cobre arsenical insertadas en cabos de madera y algunos de los instrumentos de acero utilizados actualmente en los Andes del norte del Perú y del sur del Ecuador: barretas, barretillas, barretones y pequeñas lampas. Y por otro, indicar, en base a datos etnográficos, la relación entre estos instrumentos y los allachus, kituchis y chaquitacllas que emplean los campesinos de las tierras alto andinas del centro y el sur del Perú. Esto con la finalidad de abogar para la elaboración de una historia de la tecnología andina. Prehispanic metal points and ploughshares in the Andes and their continuity until the present Abstract: This article shows the continuity in the production of multiple use tools that where made beginning AD 900 by the Sicán people of Batán Grande, in the Department of Lambayeque, Peru. These tools are arsenical cooper

Estrés y síntomas en personal de salud del Hospital Universitario de Los Andes.

OpenAIRE

Manzanilla, María D.; Molina de González Méndez, Tivizay; Caltagirone, Raimondo; Vera , Mariflor; Torres, Adrián R.

2007-01-01

Editorial. ¡Ya tenemos símbolo, ícono o logotipo!. Now we have symbol, icono or logo!. Salinas, Pedro José Accidentes domésticos en ancianos. Municipio Libertador. Mérida. 1993-1996. Domestics accidents in elderly people. Libertador County of Mérida State. 1993-1996. Salinas, Pedro José Rojas Márquez, Reina Estrés y síntomas en personal de salud del Hospital Universitario de Los Andes. Stress and symptoms in health staff of the Hospital Universitario de Los Andes. Méri...

Migraciones en la puna: su relación con el uso de los recursos naturales del departamento Los Andes Migraciones en la puna: su relación con el uso de los recursos naturales del departamento Los Andes

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Francisco R. Barbarán

2009-12-01

Full Text Available From an historic and demographic perspective, as well as the use of natural resources, we analyzed the relationship between human migrations and the economic activities of Los Andes Department, West of the Salta Province, in NW Argentina. Using the residual method, we calculated migratory balances between Argentinean population censuses carried out in 1947,1960, 1970, 1980 and 2001. The migratory balances were negative for all the periods studied. When the train started to run through Ramal C-14, the workers who built it have to find jobs somewhere else. At the same time, the railway made easier for the natives, to find better economicopportunities out of the Puna. The close of mine La Casualidad by the end of the 70’s, the low creation of jobs by the remaining mining operations, focused in to hire qualified technicians no available in Los Andes and the privatization of the railway in early 90’s, were important factors of emigration. Despite of cattle rising as the main economic activity in rural areas, it is practiced without any technology of management. The overgrazing caused for that reason, has reduced almost to the half the quantity of sheep by inhabitant between 1947 and 2001. That is why the local people have to press more on the wildlife, trading illegally with vicuña (Vicugna vicugna fiber. Despite of a touristic development plan, a law promoting sheep rising and a census of vicuña population carried out by the provincial government, these recent actions should be part of a development project of regional scale, oriented to the sustainable use of the natural resources of Los Andes Department. That project would create jobs and discourage emigration.Desde una perspectiva histórica, demográfica y del uso de los recursos naturales, analizamos la relación existente entre las migraciones humanas y las actividades económicas en el departamento Los Andes, ubicado al W de la provincia de Salta, en el Noroeste Argentino. Usando el m

Ausentismo laboral de causa médica en el Instituto Autónomo Hospital Universitario de Los Andes.

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Parada de Denis, María Eugenia; Rivas Padilla, Fernando; Moreno Barrios, Reyla; Rincón, Eglis; Mejía, Zurayma; Mora, Dania Margarita

2006-01-01

Editorial. ¡Ya tenemos símbolo, ícono o logotipo!. Now we have symbol, icono or logo!. Salinas, Pedro José Accidentes domésticos en ancianos. Municipio Libertador. Mérida. 1993-1996. Domestics accidents in elderly people. Libertador County of Mérida State. 1993-1996. Salinas, Pedro José Rojas Márquez, Reina Estrés y síntomas en personal de salud del Hospital Universitario de Los Andes. Stress and symptoms in health staff of the Hospital Universitario de Los Andes. Méri...

Constuccion social de comuninad y migración en Usibamba : un estudio sobre el impacto de los procesos de globalización en los Andes centrales del Perú

NARCIS (Netherlands)

Gilvonio Perez, J.M.

2009-01-01

The research for the thesis was conducted in the village of Usibamba, located in a high-Andean area called Alto Cunas east from the Mantaro Valley in the Peruvian Central Andes. Special attention was paid to the institutional context and the everyday life conditions in which the social construction

Mountain building in the central Andes

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Kono, Masaru; Fukao, Yoshio; Yamamoto, Akihiko

1989-04-01

The Central Andes is the middle part of the Andean chain between about 13°S and 27°S, characterized by the parallel running high mountain chains (the Western and Eastern Cordilleras) at the edges of high plateaus with a height of about 4000 m and a width of 200 to 450 km (the Altiplano-Puna). From the examination of geophysical and geological data in this area, including earthquakes, deformation, gravity anomaly, volcanism, uplift history, and plate motion, we conclude that the continued plate subduction with domination of compressive stress over the entire arc system is the main cause of the tectonic style of the Central Andes. We propose that the present cycle of mountain building has continued in the Cenozoic with the most active phase since the Miocene, and that the present subduction angle (30°) is not typical in that period but that subduction with more shallowly dipping oceanic lithosphere has prevailed at least since the Miocene, because of the young and buoyant slab involved. This situation is responsible for the production of a broad zone of partial melt in the mantle above the descending slab. Addition of volcanic materials was not restricted to the western edge (where active volcanoes of the Western Cordillera exist) but extended to the western and central portion of the Altiplano-Puna. The western half of the Central Andes is essentially isostatic because the heat transferred with the volcanic activities softened the crust there. In the eastern edge, the thermal effect is small, and the crust is strongly pushed by the westward moving South American plate. This caused the shortening of crustal blocks due to reverse faulting and folding in the Eastern Cordillera and Amazonian foreland. The magmatism and crustal accretion are dominant at the western end of the mountain system and decrease eastward, while the compression and consequent crustal shortening are strongest at the eastern end and wane toward west. These two processes are superposed between

Caracterización morfométrica de la microcuenca de la quebrada los Andes, El Carmen de Viboral, Antioquia-Colombia Morphometrical characterization in los Andes watershed, El Carmen de Viboral, Antioquia-Colombia

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Yimmy Montoya Moreno

2009-07-01

Full Text Available Se evaluaron algunas características morfométricas básicas en la microcuenca de la quebrada Los Andes en el departamento de Antioquia (Colombia. La microcuenca tiene un área pequeña (Some morphometric characteristic were evaluated in the watershed of creek Los Andes department of Antioquia (Colombia. The headwater has a small area (<20km² with main direction in the axis S-N, with an elevation range between 2.700 and 2.200 m. asl. It presents a network of drainage well structured, for which presents a time of concentration of the water over 5 hours. The watershed is of class Kc2 with a high slope and a system of drainage subdendritic. This research permitted to identify the uses of the soil, being the adequate use the one that presented greater percentage (55% and the use is recommended conservationist in general for all headwater.

Analysis of La Dehesa paleo-landslide. Central Pre-Andes of Argentina

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Tapia Baldis, Carla; Rothis, Luis Martín; Perucca, Laura; Esper Angillieri, María; Vargas, Horacio; Ponce, David; Allis, Carlos

2018-04-01

The main objective of this paper is to consider the influence of Quaternary faults as likely triggering factor for rockslides occurrence in the Central Pre-Andes, a region with intense shallow seismic activity. A rockslide deposit was selected as study case, placed in the western flank of La Dehesa and Talacasto (DT) range (31°3‧37″ S and 68°46‧ 8″ W). Applied methodology includes the characterization of main discontinuities, reconstruction of the topography using a high-resolution digital elevation model, safety factor calculation along the sliding surface and, Newmark displacements estimation for three different hypothetical seismic scenarios, recreated from existing neotectonic local information. Equilibrium-limit method's results confirm that study case, La Dehesa rockslide (LDR), had a stable and safe slope's configuration under static conditions. However, a seismic horizontal coefficient between 0.2 and 0.3 decreases safety factor below the safety threshold. Newmark's displacements for different seismic reconstructed scenarios varies between 4.1 and 15.9 cm, values that agreed with a coherent failure process, likely triggered by Pleistocene to Holocene seismogenic sources in Central Pre-Andes. LDR trigger could be assigned mainly to an earthquake related to La Dehesa Quaternary fault (LDF) activity; however, similar movements produced by neighboring faults should not be discarded. LDR triggering related to climatic conditions is despised. Finally, the methodology presented in this work is easy to reproduce and may be applied to other rockslides located in the mountainous areas of the Central Pre-Andes of Argentina.

Tectonic control of erosion in the southern Central Andes

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Val, Pedro; Venerdini, Agostina L.; Ouimet, William; Alvarado, Patricia; Hoke, Gregory D.

2018-01-01

Landscape evolution modeling and global compilations of exhumation data indicate that a wetter climate, mainly through orographic rainfall, can govern the spatial distribution of erosion rates and crustal strain across an orogenic wedge. However, detecting this link is not straightforward since these relationships can be modulated by tectonic forcing and/or obscured by heavy-tailed frequencies of catchment discharge. This study combines new and published along-strike average rates of catchment erosion constrained by 10Be and river-gauge data in the Central Andes between 28°S and 36°S. These data reveal a nearly identical latitudinal pattern in erosion rates on both sides of the range, reaching a maximum of 0.27 mm/a near 34°S. Collectively, data on topographic and fluvial relief, variability of rainfall and discharge, and crustal seismicity suggest that the along-strike pattern of erosion rates in the southern Central Andes is largely independent of climate, but closely relates to the N-S distribution of shallow crustal seismicity and diachronous surface uplift. The consistently high erosion rates on either side of the orogen near 34°S imply that climate plays a secondary role in the mass flux through an orogenic wedge where the perturbation to base level is similar on both sides.

Efectos del cambio climático sobre especies de plantas vasculares del sur de los Andes Centrales: un estudio en el noroeste de Argentina (NOA)

OpenAIRE

Godoy Bürki, Ana Carolina

2017-01-01

La región de los Andes Tropicales es considerada como una región muy vulnerable al cambio climático porque presenta una alta diversidad y endemismo y porque posee una gran variabilidad altitudinal. Si bien se ha efectuado un gran número de predicciones sobre los cambios que ocurrirán en el clima, pocos estudios evaluaron el impacto que éste tendrá sobre las distribuciones de las especies. En este estudio se estima el efecto del cambio climático sobre la distribución y la conservación de espec...

Distribución de Stenocercus guentheri (Sauria: Iguanidae en el sur de los Andes de Colombia

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Castro Herrera Fernando

1993-12-01

Full Text Available The morphology of a population of Stenocercus guentherifrom Colombia is described in detail and compared to information from ecuadorean specimens. The range of the species is extended northward to include the colombian departments (provinces of Nariño and Cauca along the Andes. Some field observations about bahavior, habitat, and reproduction are included.El presente trabajo describe las características de Stenocercus guentheri, en las poblaciones del sur de Colombia y hace una comparación con la información del Ecuador. Se amplía su rango de distribución geográfica hacia el norte de Suramérica, incluyendo los departamentos de Nariño y Cauca en los Andes de Colombia. Se incluyen datos de campo sobre hábitat, hábitos y reproducción.

Oroclinal Bending and Mountain Uplift in the Central Andes

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Mpodozis, C.; Arriagada, C.; Roperch, P.

2007-05-01

The large paleomagnetic database now available for the Central Andes permits a good understanding of the overall spatial and temporal variations of rotations. Mesozoic to Early Paleogene rocks along the forearc of northern Chile (23°-28°S) record significant clockwise rotations (>25°) [Arriagada et al., 2006, Tectonics, doi:10.1029/2005TC001923]. Along the forearc of southern Peru, counterclockwise rotations recorded within flat lying red-beds (Moquegua Formation) increase from about -30° at 17.5°S to - 45° at15.5°S and decrease through time from the late Eocene to the late Oligocene-early Miocene [Roperch et al., 2006, Tectonics, doi:10.1029/2005TC001882]. Recently published thermo-chronological studies show evidence for strong exhumation within Bolivian Eastern Cordillera and the Puna plateau starting in the Eocene while structural studies indicate that the majority of crustal shortening in the Eastern Cordillera occurred during the Eocene-Oligocene, although the final stages of deformation may have continued through the Early Miocene. Rotations in the Peruvian and north Chilean forearc thus occurred at the same time than deformation and exhumation/uplift within the Eastern Cordillera. In contrast Neogene forearc rocks in southern Peru and northern Chile do not show evidences of rotation but low magnitude (10°) counterclockwise rotations are usually found in mid to late Miocene rocks from the northern Altiplano. These Neogene rotations are concomitant with shortening in the Sub-Andean zone and sinistral strike-slip faulting along the eastern edge of the northern Altiplano. We interpret the rotation pattern along the southern Peru and north Chile forearc as a result of strong late Eocene- late Oligocene oroclinal bending of the Central Andes associated with shortening gradients along the Eastern Cordillera associated both with the Abancay deflection and the Arica bend. The amount and spatial distribution of pre-Neogene shortening needed to account for

Religión, género y construcción de una sexualidad en los Andes (Siglos XVI y XVII. Una acercamiento provisional

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Armas Asin, Fernando

2001-12-01

Full Text Available This study emphasizes the conceptual changes in regard to sex, sexuality and general genre relations in the Andes, in the 16th and 17th centuries, in the context of the establishment of the colonial society. It is analyzed the way in which a new discourse on the body was developed as a consequence of the deeply represive baroque culture. This culture recreated religious values which controlled every aspect of the daily life. It also enforced a rigid legislation which ruled through society as a whole.

El estudio busca enfatizar los cambios conceptuales que se produjeron en torno al sexo, la sexualidad, y, en términos generales, en las relaciones de género en los Andes en los siglos XVI y XVII, en un contexto de establecimiento de la sociedad colonial. Se analiza cómo se construyó un nuevo discurso sobre el cuerpo en los Andes como consecuencia de la cultura barroca, profundamente represiva. Dicha cultura recreó valores religiosos que controlaban todos los aspectos de la vida diaria, además de poner en marcha una legislación muy rígida que reguló toda la sociedad.

Mixed bird flocks: patterns of activity and species composition in a region of the Central Andes of Colombia Bandadas mixtas de aves: patrones de actividad y composición de especies en una región de la Cordillera Central de los Andes de Colombia

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Enrique Arbeláez-Cortés

2011-06-01

Full Text Available Mixed bird flocks are groups of individuals from different species that travel and forage together. Such groups are common in several bird communities around the world. We present species composition and activity patterns of mixed bird flocks in a region of the Central Andes of Colombia. We compared the number of species per flock, as well as the number of flocks among 3 different habitats. We tested hypotheses concerning the flocks daily activity and the co-occurrences of species within them. We recorded 75 species, and the species number per flock varied from 4 to 21. Our data suggest that habitat affects the number of flocks but not their species number, and that the activity of flocks is similar throughout the day. In addition, the association of birds in flocks is affected by interspecific facilitation, with some species co-occurrences found more times than expected by chance. We hypothesize that some tanager species could have a role in flock cohesion. We witnessed 2 predator attacks upon flocks, a number of agonistic interactions among flock members, and squirrels following bird flocks. Our results meet some general patterns described for mixed bird flocks.Las bandadas mixtas de aves son grupos de individuos de diferentes especies que viajan y forrajean juntos, y son comunes en varias comunidades de aves alrededor del mundo. Presentamos la composición de especies y los patrones de actividad de las bandadas mixtas de aves en una región de la Cordillera Central de los Andes Colombianos. Comparamos el número de especies por bandada y el número de bandadas en 3 hábitats distintos. Evaluamos hipótesis relacionadas con la actividad de las bandadas durante el día y la presencia simultánea de especies en estos grupos. Observamos 75 especies, y el número de especies por bandada varió entre 4 y 21. Nuestros datos indican que el hábitat parece afectar el número de bandadas pero no su número de especies y que la actividad de las bandadas

Hydrological Modeling of Highly Glacierized Basins (Andes, Alps, and Central Asia

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Nina Omani

2017-02-01

Full Text Available The Soil and Water Assessment Tool (SWAT was used to simulate five glacierized river basins that are global in coverage and vary in climate. The river basins included the Narayani (Nepal, Vakhsh (Central Asia, Rhone (Switzerland, Mendoza (Central Andes, Argentina, and Central Dry Andes (Chile, with a total area of 85,000 km2. A modified SWAT snow algorithm was applied in order to consider spatial variation of associated snowmelt/accumulation by elevation band across each subbasin. In previous studies, melt rates varied as a function of elevation because of an air temperature gradient while the snow parameters were constant throughout the entire basin. A major improvement of the new snow algorithm is the separation of the glaciers from seasonal snow based on their characteristics. Two SWAT snow algorithms were evaluated in simulation of monthly runoff from the glaciered watersheds: (1 the snow parameters are lumped (constant throughout the entire basin and (2 the snow parameters are spatially variable based on elevation bands of a subbasin (modified snow algorithm. Applying the distributed SWAT snow algorithm improved the model performance in simulation of monthly runoff with snow-glacial regime, so that mean RSR decreased to 0.49 from 0.55 and NSE increased to 0.75 from 0.69. Improvement of model performance was negligible in simulations of monthly runoff from the basins with a monsoon runoff regime.

Facies volcánicas del depósito de avalancha de detritos del volcán Tata Sabaya, Andes Centrales Volcanic facies of the debris avalanche deposit of Tata Sabaya Volcano, Central Andes

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Benigno Godoy

2012-09-01

Full Text Available Las avalanchas de detritos, asociadas a colapsos parciales de edificios volcánicos, son fenómenos comunes en la evolución de un volcán. Este tipo de flujos son por inestabilidades, que pueden deberse a factores tales como la existencia de zonas afectadas por alteración hidrotermal, cambios climáticos, terremotos, intrusión de magmas en zonas superficiales (criptodomos y/o diques y/o movimiento de fallas bajo el edificio volcánico o cercanas a él. El producto final de estos flujos -denominado depósito de avalancha de detritos (DAD- presenta morfologías típicas de cerrillos y drenajes cerrados. En los Andes Centrales se han reconocido, al menos, 14 centros volcánicos con depósitos de avalancha asociados, entre los que está el volcán Tata Sabaya (Bolivia. El colapso que ha dado origen a este depósito podría haberse generado por una combinación de actividad sísmica y magmática en el volcán. El depósito asociado al colapso parcial de este volcán se distribuye sobre la parte baja del flanco sur del volcán y sobre la parte noroccidental de la cuenca del salar de Coipasa. Cubre una superficie de más de 230 km² y tiene un volumen estimado de 6±1 km³. Sobre la base de las composiciones litológicas, se ha establecido que el depósito está constituido por 6 tipos distintos de cerrillos, los cuales son: lávicos, piroclásticos, sedimentarios mixtos, brecha piroclástica y andesítico-basálticos. Considerando el tipo predominante de cerrillos y su distribución espacial dentro del depósito, se ha definido 6 facies diferentes (Facies de Bloques Toreva, Facies de Cerrillos Volcánicos, Facies Central, Facies de Cerrillos Sedimentarios, Facies Mixta y Facies de Cerrillos de Brecha Piroclástica. Tomando en cuenta la distribución espacial de estas facies, se propone la estructura del paleovolcán previa a su colapso parcial.Debris avalanches associated with partial sector collapse of volcanic edifices are common phenomena in the

Floristic changes in alpine plant communities induced by the cushion plant Azorella madreporica (Apiaceae in the Andes of central Chile Cambios florísticos en comunidades de plantas alpinas inducidos por la planta en cojín Azorella madrepórica (Apiaceae en los Andes de Chile central

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CONSTANZA L QUIROZ

2009-06-01

. Este trabajo evalúa el efecto de una planta en cojín, Azorella madrepórica (Apiaceae, sobre la riqueza de especies, abundancia de especies, diversidad y equitatividad de la comunidad de plantas vasculares en dos altitudes en los Andes de Chile central. Teóricamente, el impacto de esta especie nodriza sobre la estructura comunitaria debería ser mayor a mayor altitud. Los resultados mostraron que la proporción de especies de plantas asociadas con plantas en cojín aumenta con la altitud, y que la abundancia de algunas especies también es mayor al interior de cojines que en el suelo desnudo. Aunque la riqueza relativa de especies al interior de los cojines aumenta con la altitud, la diversidad y la equidad fueron mayores en el suelo desnudo. Los resultados sugieren que la importancia de las plantas en cojín sobre la estructura comunitaria cambia con la altitud, produciendo mayores diferencias en los ensambles de especies presentes dentro y fuera de A. madrepórica en la mayor altitud. Basándonos en esto, sugerimos que otros atributos además de la riqueza de especies deben ser incluidos en futuros estudios para analizar el impacto de las especies nodrizas en la estructura de las comunidades a lo largo de gradientes ambientales.

LA CUEVA ALIHUÉN, NUEVOS REGISTROS DE PINTURAS RUPESTRES EN LA VEGA DE MAIPÚ (SAN MARTÍN DE LOS ANDES, PATAGONIA, ARGENTINA (The Alihuén Cave, New Records of Cave Paintings in the Maipú Valley (San Martín de los Andes, Patagonia, Argentina

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Alberto Enrique Pérez

2014-06-01

Full Text Available Se presenta el resultado de las nuevas investigaciones de pinturas rupestres en la vega Maipú, San Martín de los Andes, Neuquén, Argentina; donde se destaca la presencia de motivos zoomorfos, especialmente camélidos, de escasa representación hasta la fecha en el registro zooarqueológico local. El sitio Cueva Alihuén amplía la diversidad de motivos y técnicas de las pinturas rupestres de la vega Maipú, lo que nos permite plantear aspectos tanto biogeográficos respecto a la fauna como sobre la circulación de información y movilidad. Ambos aspectos nos permiten, nuevamente, aunar ambas vertientes de la cordillera de los Andes, compartiendo, integrando y complementando cada vez más características con el resto de los sitios que componen la cuenca hidrográfica de Valdivia, cuyo sector inferior constituye nuestra área de estudio. ENGLISH: New results from research on the cave paintings of the Maipú Valley, San Martín de los Andes, Neuquén, Argentina, highlight the presence of zoomorphic motifs, especially camelids which have been underrepresented in the local zooarchaeological record. The Alihuén cave site expands the range of motifs and techniques known from the cave paintings of the Maipú Valley that allows us to raise issues regarding both biogeographic wildlife, and on the flow of information and human mobility. These aspects allow us to share and integrate the increasingly complementary features on both sides of the Andes with the rest of the sites that comprise the Valdivia River basin, whose lower section composed our study area.

Facing unprecedented drying of the Central Andes? Precipitation variability over the period AD 1000–2100

International Nuclear Information System (INIS)

Neukom, Raphael; Salzmann, Nadine; Huggel, Christian; Rohrer, Mario; Calanca, Pierluigi; Acuña, Delia; Christie, Duncan A; Morales, Mariano S

2015-01-01

Projected future trends in water availability are associated with large uncertainties in many regions of the globe. In mountain areas with complex topography, climate models have often limited capabilities to adequately simulate the precipitation variability on small spatial scales. Also, their validation is hampered by typically very low station density. In the Central Andes of South America, a semi-arid high-mountain region with strong seasonality, zonal wind in the upper troposphere is a good proxy for interannual precipitation variability. Here, we combine instrumental measurements, reanalysis and paleoclimate data, and a 57-member ensemble of CMIP5 model simulations to assess changes in Central Andes precipitation over the period AD 1000–2100. This new database allows us to put future projections of precipitation into a previously missing multi-centennial and pre-industrial context. Our results confirm the relationship between regional summer precipitation and 200 hPa zonal wind in the Central Andes, with stronger Westerly winds leading to decreased precipitation. The period of instrumental coverage (1965–2010) is slightly dryer compared to pre-industrial times as represented by control simulations, simulations from the past Millennium, ice core data from Quelccaya ice cap and a tree-ring based precipitation reconstruction. The model ensemble identifies a clear reduction in precipitation already in the early 21st century: the 10 year running mean model uncertainty range (ensemble 16–84% spread) is continuously above the pre-industrial mean after AD 2023 (AD 2028) until the end of the 21st century in the RCP2.6 (RCP8.5) emission scenario. Average precipitation over AD 2071–2100 is outside the range of natural pre-industrial variability in 47 of the 57 model simulations for both emission scenarios. The ensemble median fraction of dry years (defined by the 5th percentile in pre-industrial conditions) is projected to increase by a factor of 4 until 2071�

Prediction of extreme floods in the Central Andes by means of Complex Networks

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Boers, Niklas; Bookhagen, Bodo; Barbosa, Henrique; Marwan, Norbert; Kurths, Jürgen; Marengo, Jose

2014-05-01

Based on a non-linear synchronisation measure and complex network theory, we present a novel framework for the prediction of extreme events of spatially embedded, interrelated time series. This method is general in the sense that it can be applied to any type of spatially sampled time series with significant interrelations, ranging from climate observables to biological or stock market data. In this presentation, we apply our method to extreme rainfall in South America and show how this leads to the prediction of more than 60% (90% during El Niño conditions) of extreme rainfall events in the eastern Central Andes of Bolivia and northern Argentina, with only 1% false alarms. From paleoclimatic to decadal time scales, the Central Andes continue to be subject to pronounced changes in climatic conditions. In particular, our and past work shows that frequency as well as magnitudes of extreme rainfall events have increased significantly during past decades, calling for a better understanding of the involved climatic mechanisms. Due to their large spatial extend and occurrence at high elevations, these extreme events often lead to severe floods and landslides with disastrous socioeconomic impacts. They regularly affect tens of thousands of people and produce estimated costs of the order of several hundred million USD. Alongside with the societal value of predicting natural hazards, our study provides insights into the responsible climatic features and suggests interactions between Rossby waves in polar regions and large scale (sub-)tropical moisture transport as a driver of subseasonal variability of the South American monsoon system. Predictable extreme events result from the propagation of extreme rainfall from the region of Buenos Aires towards the Central Andes given characteristic atmospheric conditions. Our results indicate that the role of frontal systems originating from Rossby waves in polar latitudes is much more dominant for controlling extreme rainfall in

Les Andes Centrales Tropicales vues par deux géographes: Isaiah Bowman et Carl Troll

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1978-01-01

Full Text Available Deux visions des Andes vues par deux géographes, Isaiah BOWMAN et Carl TROLL, au caractère et au milieu intellectuel différents. L'auteur étudie dans l'un et l'autre cas la méthode d'analyse de l'espace géographique et les conclusions tirées par chacun d'eux. I. BOWMAN, Américain, convaincu qu'une économie mercantiliste fondée sur l'exportation permettra aux Etats andins d'accéder à un modèle de développement, décrit les vastes contrées amazoniennes comme un futur El Dorado entre les mains de colons. L'aménagement des basses plaines selon des schémas nord-américains est le pilier de l'économie alors que les Andes abritant les communautés indigènes constituent un frein au développement. De ce fait il laisse de côté l'étude des paysanneries andines. Toute différente est la démarche de Carl TROLL dont la formation à la fois en sciences humaines et naturelles, lui permet de cerner l'espace géographique comme cadre de vie des sociétés. L'utilisation des étages écologiques, le développement de l'Empire Inca fondé sur l'étage des 'punas', la démarche historique des analyses minutieuses de Carl TROLL donne un éclairage nouveau aux relations des sociétés andines et des milieux naturels avec lesquels elles composent. Dos puntos de vista de los Andes por dos geógrafos, Isaiah BOWMAN y Carl TROLL con carácter y medio intelectual distintos. El autor estudia en ambos casos el método de análisis del espacio geográfico y las conclusiones sacadas por cada uno de ellos. I. BOWMAN, americano, convencido que una economía mercantil fundada sobre la exportación permitirá a los estados andinos acceder a un modelo de desarrollo, describe las extensas llanuras amazónicas como un El Dorado futuro entre las manos de los colonos. El desarrollo de las llanuras bajas según esquemas norteamericanos constituye el pilar de la economía mientras los Andes abrigando las comunidades indígenas se comportan como un freno al

Photosynthetic performance of Colobanthus quitensis (Kunth Bartl. (Caryophyllaceae in a high-elevation site of the Andes of central Chile Desempeño fotosintético de Colobanthus quitensis (Kunth Bartl. (Caryophyllaceae en los Andes de Chile central

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M. ANGÉLICA CASANOVA-KATNY

2006-03-01

Full Text Available Photosynthesis of Colobanthus quitensis and mesoclimatic conditions of air temperature and light intensity during the growing season were investigated at 2,650 m in the central Chilean Andes. On three typical days of the growing period (January, March and May, CO2 exchange and chlorophyll fluorescence were measured. In addition, a series of fluorescence response curves with increasing light intensity at different temperatures were performed to estimate the propensity of Andean C. quitensis populations to be photoinhibited. Net Photosynthesis (Pn was low (ca. 2.0 mmol CO2 m-2s-1 during the morning and noon in days with high photosynthetic active radiation (PAR, above 1,800 mmol photons m-2s-1. Pn increased in the afternoon (3.5-4.8 mmol CO2 m-2s-1 when PAR decreased to ca. 1,400 mmol photons m-2s-1 and leaf temperature were ca. 20 °C. Fv/Fm in the diurnal periods was between 0.7-0.75 without evidence of photoinhibition. Leaves at 15 and 22 °C exhibited a slow decrease of F PSII with the increase in actinic light intensity, although the fraction of reaction centers open (expressed by qP remained higher at 22 °C. NPQ was saturated at light intensities close to 500 mmol photons m-2s-1 in leaves at 22 °C and at higher intensities at 15 °C, suggesting that NPQ could be a mechanism of energy dissipation at high light intensity and high leaf temperature in the field. Our results indicated that C. quitensis is not photodamaged during the diurnal cycle and that the low Pn registered during some diurnal periods are likely to be related with photorespiration, which has been suggested as an efficient protective mechanism for photoinhibition in alpine plants. Our results are also compared with the photosynthetic performance of C. quitensis populations from the maritime AntarcticSe estudió la fotosíntesis de Colobanthus quitensis y las condiciones mesoclimáticas de temperatura del aire e intensidad lumínica a 2.650 m en los Andes de Chile central. Se

Comunidad y desarrollo en los Andes Peruanos: una crítica etnográfica al programa de modernidad/colonialidad

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Pieter de Vries

2013-08-01

Full Text Available En las últimas décadas la desconstrucción del desarrollo, conocida como el 'postdesarrollismo', ha cobrado gran auge en las ciencias sociales. En Latino-américa el programa teórico denominado modernidad/colonialidad/descolonialidad (MCD se propone descolonizar el pensamiento moderno re-escribiendo la historia global a partir de la experiencia colonial. Arturo Escobar, uno de los mayores teóricos del paradigma postdevelopmentalista se apoya en el proyecto MCD para pensar 'alternativas a la modernidad'(o transmodernidad. En este artículo propongo someter la perspectiva postdesarrollista y el proyecto MCD a un test etnográfico. Para eso me centro en las visiones y experiencias de Usibamba, una comunidad en los Andes Centrales Peruanos. La etnografía gira alrededor de la siguiente pregunta: ¿porqué los usibambinos, a pesar de todas sus experiencias negativas con el aparato del desarrollo, insisten en reivindicar la promesa del desarrollo? El programa de MCD nos permite entender el impasse de la comunidad en Usibamba? ¿Conceptos como pluriverso y transmodernidad nos permiten entender los deseos y aspiraciones de los usibambinos? Para responder a estas preguntas me apoyo en un análisis Žižekian que distingue entre 'lo actual', 'lo virtual', y lo 'Real'de la comunidad.

La Cordillera de los Andes: presentación de los problemas geomorfológicos

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1974-01-01

érites sont souvent déblayées sur les pentes fortes par le ruissellement et les divers glissements et éboulements. El alzamiento en bóveda del Ponto-plioceno ha dado a los .Andes su volumen montañoso actual y ha llevado a más de 4000 m superficies de erosión elaboradas durante e! Terciario. Estas superficies o 'puna' son muy probablemente poligénicas y policíclicas. Están dominadas por grandes cordilleras que son generalmente horsts que delimitan los sectores de surrección máxima, horsts que son posteriores a la elaboración de la superficie de las mesetas. Esta superficie está deformada tanto sobre los bordes de las cuencas interiores como sobre los flancos de la montaña donde ella ha sido disectada y reducida a bandas. Algunas veces esta superficie ha podido desaparecer debido a su recorte en lo alto de los flancos de los grandes valles, sobretodo en los dos extremos de la cadena. A un nivel inferior, se desarrollaron aplanamientos menores durante el Plioceno y posiblemente durante el Cuaternario antiguo, en sectores que habían permanecido relativamente estables: son los 'glacis' de erosión en lazos del altiplano perú-boliviano o las superficies de abrasión retocadas en 'glacis' sobre los abombamientos costeros perú-chilenos. Algunos grandes valles están adaptados a las grandes direcciones estructurales consecutivas a los movimientos del fin de Terciario (la adaptación del conjunto va acompañada a menudo de numerosas inadaptaciones locales. Otros valles siguen antiguas direcciones estructurales, anteriores al alzamiento andino. El Cuaternario está marcado por una serie de períodos fríos acompañados de glaciaciones en la montaña. Se ha podido determinar lar existencia de cuatro glaciaciones distintas de las cuales una al menos remonta al Cuaternario antiguo. Las glaciaciones recientes son contemporáneas de las glaciaciones del Cuaternario reciente de Europa y de América del Norte. Sus causas hay que buscarlas, para las latitudes medias, en un

Tectogénesis, orogénesis y volcanismo en los Andes del Sur del Perú

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1975-01-01

-volcans essentiellement andésitiques a donné à la Cordillère Occidentale sa physionomie actuelle. En el Sur del Perú, los plegamientos andinos (tectogenesis no han sido generadores de relieves importantes, mientras que los movimientos epeirogénicos han creado verdaderamente el relieve de los Andes (orogénesis dando lugar a un volcanismo de un poder considerable. Desde el punto de vista geomorfológico, las estructuras puestas en lugar por los movimientos tangenciales andinos han dejado de expresarse topográficamente hacia mediados del Mioceno a raíz del aplanamiento general de la región (superficie de la Puna. Igualmente, los relieves importantes creados por los movimientos epeirogénicos y las acumulaciones volcánicas que los acompañaban (Volcanismo Toquepala del Eoceno y Volcanismo Tacaza del Oligo-Mioceno, han sido por completo enrasados. En estas condiciones, lo esencial del volumen actual de los Andes fue obra de la orogénesis y del volcanismo de los últimos 15 millones de años La puesta en lugar se ha efectuado en dos etapas. La primera ha comenzado por acumulaciones ignimbríticas (Formación Huaylillas que han fosilizado la superficie del aplanamiento en todo el Sur del Perú Este volcanismo de fisura correspondía al comienzo de un período de distensión que se tradujo por el levantamiento de los Andes al final del Mioceno. Después de una corta interrupción (durante la cual hay que colocar una fase de compresión durante el Plioceno, la segunda etapa ha sido marcada por el levantamiento de toda la región, quedando comprendida la zona costera. El comienzo de esta nueva fase de distensión ha dado lugar a emisiones ignimbríticas y piroplásticas (Formación Maure, Sillar, Formaciones Sencca y Capillune cuyos productos han llenado las cuencas de erosión resultantes del rejuvenecimiento de la superficie de la Puna. Como resultado, a medida que el levantamiento ha tomado amplitud (Pleistoceno, el volcanismo ha cambiado de carácter, y bajo la cubierta de ignimbr

Mio-Pliocene aridity in the south-central Andes associated with Southern Hemisphere cold periods.

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Amidon, William H; Fisher, G Burch; Burbank, Douglas W; Ciccioli, Patricia L; Alonso, Ricardo N; Gorin, Andrew L; Silverhart, Perri H; Kylander-Clark, Andrew R C; Christoffersen, Michael S

2017-06-20

Although Earth's climate history is best known through marine records, the corresponding continental climatic conditions drive the evolution of terrestrial life. Continental conditions during the latest Miocene are of particular interest because global faunal turnover is roughly synchronous with a period of global glaciation from ∼6.2-5.5 Ma and with the Messinian Salinity Crisis from ∼6.0-5.3 Ma. Despite the climatic and ecological significance of this period, the continental climatic conditions associated with it remain unclear. We address this question using erosion rates of ancient watersheds to constrain Mio-Pliocene climatic conditions in the south-central Andes near 30° S. Our results show two slowdowns in erosion rate, one from ∼6.1-5.2 Ma and another from 3.6 to 3.3 Ma, which we attribute to periods of continental aridity. This view is supported by synchrony with other regional proxies for aridity and with the timing of glacial ‟cold" periods as recorded by marine proxies, such as the M2 isotope excursion. We thus conclude that aridity in the south-central Andes is associated with cold periods at high southern latitudes, perhaps due to a northward migration of the Southern Hemisphere westerlies, which disrupted the South American Low Level Jet that delivers moisture to southeastern South America. Colder glacial periods, and possibly associated reductions in atmospheric CO 2 , thus seem to be an important driver of Mio-Pliocene ecological transitions in the central Andes. Finally, this study demonstrates that paleo-erosion rates can be a powerful proxy for ancient continental climates that lie beyond the reach of most lacustrine and glacial archives.

Los costos de la expedición militar a Chile, 1815-1818

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Beatriz Bragoni

2016-09-01

Full Text Available Este trabajo explora las estrategias utilizadas para financiar la creación y el sostenimiento del Ejército de los Andes y los instrumentos fiscales utilizados para conseguirlo. El análisis de los distintos rubros que integraban las cajas del ejército permite examinar el peso de los recursos aportados por el gobierno central y por la jurisdicción cuyana. Asimismo, analiza el destino de los fondos a través del estudio de los presupuestos del ejército, con el objetivo de ponderar el peso que tuvieron los salarios en el total de los gastos militares durante la etapa previa al cruce de los Andes, y en la posterior, cuando el ejército estaba en Chile bajo severas condiciones fiscales de los gobiernos patriotas.

Mario Alberto Cajas Sarria (2015. La historia de la Corte Suprema de Justicia de Colombia, 1886-1991. Bogotá: Universidad de los Andes & Universidad ICESI

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Michael Cruz Rodríguez

2017-06-01

Full Text Available El libro del profesor Mario Alberto Cajas Sarria, que es resultado de su tesis doctoral en derecho en la Universidad de los Andes, realiza una narración de la historia de la Corte Suprema de Justicia de Colombia desde su creación en 1886 hasta su validación a la Asamblea Nacional Constituyente de 1991. Para ello toma como elemento central decisiones judiciales que efectuaron control constitucional en cuatro temas que sirven de hilos conductores: los estados de excepción, las leyes por vicios de trámite, los tratados internacionales y las reformas a la constitución. Así, el trabajo no sólo se detiene en las categorías jurídicas que orbitan alrededor de estos tópicos sino que, a partir de las decisiones judiciales, de la prensa y de fuentes secundarias, ilumina el contexto político y los ambientes institucionales en los que la Corte Suprema ejerció el control de constitucionalidad en algunas coyunturas en la trayectoria del régimen político colombiano.

Crustal balance and crustal flux from shortening estimates in the Central Andes

Science.gov (United States)

Hindle, David; Kley, Jonas; Oncken, Onno; Sobolev, Stephan

2005-01-01

The Central Andes of South America form the second largest high elevation plateau on earth. Extreme elevations have formed on a noncollisional margin with abundant associated arc magmatism. It has long been thought that the crustal thickness necessary to support Andean topography was not accounted for by known crustal shortening alone. We show that this may in part be due to a two-dimensional treatment of the problem. A three-dimensional analysis of crustal shortening and crustal thickness shows that displacement of material towards the axis of the bend in the Central Andes has added a significant volume of crust not accounted for in previous comparisons. We find that present-day crustal thickness between 12°S and 25°S is accounted for (∼-10% to ∼+3%)with the same shortening estimates, and the same assumed initial crustal thickness as had previously led to the conclusion of a ∼25-35% deficit in shortening relative to volume of crustal material. We suggest that the present-day measured crustal thickness distribution may not match that predicted due to shortening, and substantial redistribution of crust may have occurred by both erosion and deposition at the surface and lower crustal flow in regions of the thermally weakened middle and lower crust.

La implantación de la viruela en los Andes, la historia de un holocausto

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Uriel García Cáceres

2003-03-01

Full Text Available La historia de las epidemias de viruela en los Andes tiene el carácter tétrico del relato de un holocausto. Esta presentación está destinada a resaltar las etapas más importantes del proceso de la implantación de la viruela en las poblaciones andinas en general y, en particular, en el Perú, desde principio del siglo XVI hasta nuestros días.

Culture and landslide risk in the Central Andes of Bolivia and Peru

OpenAIRE

Nicholas Roberts

2009-01-01

Culture and its heritage play a major role in determining landslide risk in the Central Andes. Examples of some of these many possible influences are provided from natural and social science literature and from the author’s recent work in Bolivia. Landslide risk appears to have generally increased throughout the last millennium, due largely to anthropogenic modification of hazard, exposure, vulnerability and coping capacity. These changes result from both local and distant pressures and from ...

Surface uplift in the Central Andes driven by growth of the Altiplano Puna Magma Body.

Science.gov (United States)

Perkins, Jonathan P; Ward, Kevin M; de Silva, Shanaka L; Zandt, George; Beck, Susan L; Finnegan, Noah J

2016-10-25

The Altiplano-Puna Magma Body (APMB) in the Central Andes is the largest imaged magma reservoir on Earth, and is located within the second highest orogenic plateau on Earth, the Altiplano-Puna. Although the APMB is a first-order geologic feature similar to the Sierra Nevada batholith, its role in the surface uplift history of the Central Andes remains uncertain. Here we show that a long-wavelength topographic dome overlies the seismically measured extent of the APMB, and gravity data suggest that the uplift is isostatically compensated. Isostatic modelling of the magmatic contribution to dome growth yields melt volumes comparable to those estimated from tomography, and suggests that the APMB growth rate exceeds the peak Cretaceous magmatic flare-up in the Sierran batholith. Our analysis reveals that magmatic addition may provide a contribution to surface uplift on par with lithospheric removal, and illustrates that surface topography may help constrain the magnitude of pluton-scale melt production.

Glacial lakes of the Central and Patagonian Andes

Science.gov (United States)

Wilson, Ryan; Glasser, Neil F.; Reynolds, John M.; Harrison, Stephan; Anacona, Pablo Iribarren; Schaefer, Marius; Shannon, Sarah

2018-03-01

The prevalence and increased frequency of high-magnitude Glacial Lake Outburst Floods (GLOFs) in the Chilean and Argentinean Andes suggests this region will be prone to similar events in the future as glaciers continue to retreat and thin under a warming climate. Despite this situation, monitoring of glacial lake development in this region has been limited, with past investigations only covering relatively small regions of Patagonia. This study presents new glacial lake inventories for 1986, 2000 and 2016, covering the Central Andes, Northern Patagonia and Southern Patagonia. Our aim was to characterise the physical attributes, spatial distribution and temporal development of glacial lakes in these three sub-regions using Landsat satellite imagery and image datasets available in Google Earth and Bing Maps. Glacial lake water volume was also estimated using an empirical area-volume scaling approach. Results reveal that glacial lakes across the study area have increased in number (43%) and areal extent (7%) between 1986 and 2016. Such changes equate to a glacial lake water volume increase of 65 km3 during the 30-year observation period. However, glacial lake growth and emergence was shown to vary sub-regionally according to localised topography, meteorology, climate change, rate of glacier change and the availability of low gradient ice areas. These and other factors are likely to influence the occurrence of GLOFs in the future. This analysis represents the first large-scale census of glacial lakes in Chile and Argentina and will allow for a better understanding of lake development in this region, as well as, providing a basis for future GLOF risk assessments.

Clima laboral relacionado al desempeño académico de los docentes de la Facultad de Ciencias de la Salud de la Universidad Peruana los Andes Huancayo 2014

OpenAIRE

Huatuco Mateo, Wilfredo Alcides

2015-01-01

OBJETIVO: Determinar la relación entre el clima laboral y el desempeño académico en los docentes de la Facultad de Ciencias de la Salud de la Universidad Peruana Los Andes – Huancayo 2014.TIPO DE ESTUDIO: correlacional, prospectivo, transversal, observacional. DISEÑO: correlacional causal, POBLACION: 200 docentes y 394 estudiantes. MUESTRA calculada solo para los estudiantes mediante la fórmula de proporciones llegando a 310, TECNICA DE RECOLECCION DE DATOS: encuesta con el INSTRUMENTO: Cuest...

Distribución y densidad de la trucha Oncorhynchus mykiss (Salmoniformes: Salmonidae en los Andes venezolanos

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Jaime E. Péfaur

1998-09-01

Full Text Available En el presente trabajo se informa acerca de la distribución espacial y la abundancia de las poblaciones de la trucha arcoiris silvestre en los Andes Venezolanos, con base en recolectas en 68 estaciones de muestreo durante un año. Ubicadas entre 500 y 4000 msnm en siete cuencas hidrográficas de los ríos más importantes de los Andes de Venezuela. Un total de 612 individuos fueron obtenidos en estaciones por encima de los 1700 m. La mayoría de los peces de recogieron en las cuencas de los ríos Chama (43%, Motatán (21% y Santo Domingo (32%, con sólo algunos ejemplares recolectados en los ríos Negro (1.75% y La Grita (0-33%, y con ausencia de capturas en los ríos Escalante y Mocotíes. Los machos adultos superan numéricamente a las hembras en una posición de 2.15: 1. Los juveniles conforman un 56.7% del total de capturas, con una proporción de 1.30 juveniles por adulto. El tamaño de los especímenes varió desde 2.0 a 21.8 cm. Con casi la mitad de ellos dentro del intervalo 5.1 - 10.0 cm. El peso de los ejemplares también presentó una amplia variación, con un máximo de 317.0g.Spatial distribution and relative abundance of wild rainbow trout populations were studied in 68 stations located between 500 and 4000 masl in seven hydrological basins of the most important Andean rivers of Venezuela during a year of sampling. A total of 612 individuals were obtained above 1700 m. Most fishes were obtained from the Chama ( 43%, Motatán (21% and Santo Domingo (32% rivers, very few in the Negro (1.75% and La Grita (0.33% rivers, and none in the Escalante and Mocotíes rivers basins. Adult males were more abundant than females in a 2.15:1 proportion. Juveniles made a 56.7% of captures, with a proportion of 1.30 juveniles per adult. Individual sizes varied from 2.0 to 21.8 cm, most within the interval 5.1 - 10.0 cm; the weight of specimens also showed an ample variation, with a maximum of 317.0 g.

Taxonomía y biogeografía de cuatro especies de Psectrascelis (Coleoptera: Tenebrionidae de la Precordillera y Cordillera de los Andes en Mendoza, Argentina

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Gustavo E. FLORES

2005-01-01

Full Text Available El género neotropical Psectrascelis Solier (Pimeliinae: Nycteliini comprende 75 especies que se distribuyen desde el sur de Perú hasta el sur de Argentina y Chile. En este aporte se revisan las cuatro especies de Psectrascelis que habitan en el noroeste de la provincia de Mendoza (Argentina, en los cordones montañosos de la Precordillera y Cordillera de los Andes: P. deplanata (Lacordaire, 1830, P. vestita (Lacordaire, 1830, P. mamillonea (Lacordaire, 1830 y P. semistrigosa Fairmaire, 1903. Se proveen redescripciones con nuevos caracteres morfológicos, fotografías de adultos y de los pronotos, e ilustraciones de genitalia masculinos. Se consigna la distribución geográfica y rangos altitudinales para cada especie, estableciendo las provincias biogeográficas que habitan. Se presenta una discusión acerca de los patrones de distribución de las especies de Psectrascelis y de otros artrópodos epigeos que habitan en los cordones montañosos de la Precordillera y Cordillera de los Andes.

Luchas y defensas escondidas. Pluralismo legal y cultural como una práctica de resistencia creativa en la gestión local del agua en los Andes

NARCIS (Netherlands)

Boelens, R.A.

2011-01-01

En los Andes, los derechos de agua se materializan en procesos de lucha social. El artículo examina cómo la lucha por el agua de los colectivos locales no puede comprenderse sin su enraizamiento en subcorrientes dinámicas: los cimientos multicapas, a menudo ocultos, de los derechos de agua. Aquí se

Recuperación de la biomasa mediante la sucesión secundaria, Cordillera Central de los Andes, Colombia

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Jorge Ignacio del Valle

2011-09-01

Full Text Available En bosques secundarios premontanos tropicales es escasa la información sobre el tiempo requerido para recuperar la biomasa aérea y subterránea de los primarios. Por lo tanto, establecimos 33 parcelas de 0.1ha entre 550 y 1 700m en bosques secundarios que cubrían estadios serales de 3 a 36 años y estimamos la biomasa de las plantas y de las raíces gruesas con ecuaciones locales. Así como la biomasa de las pasturas y barbechos por cosecha de 54 y 18 parcelas, respectivamente. También se calculó la edad de las parcelas con informantes locales, sensores remotos, C14 y anillos de crecimiento. En cada parcela medimos la biomasa aérea viva por hectárea (Bav y la de las raíces gruesas por hectárea (Brg. Modelamos la Bav y Brg en función de la edad mediante la ecuación de von Bertalanfy con asíntotas de 247t/ha (Bav y 66t/ha (Brg resultantes de la medición de 33 parcelas de 0.1ha en los bosques primarios. Con la razón Brg/Bav=f(t estimamos 87 años para que los bosques secundarios recuperen la Bav existente en los primarios y 217 años para recuperar la Brg. La tasa máxima de crecimiento instantáneo de la Bav fue 6.95t/ha/año a los 10 años y la tasa media máxima de crecimiento 6.26t/ha/año a los 17 años. La media ponderada de la tasa de crecimiento absoluto de la Bav alcanzó 4.57t/ha/año y la relativa 10% anual. La razón Brg/Bav inicialmente aumenta muy aceleradamente hasta 4-5 años (25%, luego disminuye hasta 25 años (18% para luego incrementar hasta 26.7Biomass recovery through secondary succession in the Cordillera Central de los Andes, Colombia. Estimations on biomass recovery rates by secondary tropical forests are needed to understand the complex tropical succession, and their importance on CO2 capture, to offset the warming of the planet. We conducted the study in the Porce River Canyon between 550 and 1 700m.a.s.l. covering tropical and premontane moist belts. We established 33 temporary plots of 50mx20m in secondary

Pucarilla-Cerro Tipillas volcanic complex: the oldest recognized caldera in the southeastern portion of central volcanic zone of Central Andes?

Energy Technology Data Exchange (ETDEWEB)

Guzman, Silvina; Petrinovic, Ivan [CONICET -IBIGEO. Museo de Cs. Naturales, Universidad de Salta, Mendoza 2 (4400), Salta (Argentina)], E-mail: guzmansilvina@gmail.com

2008-10-01

We recognize the most eastern and oldest collapse caldera structure in the southern portion of the Central Volcanic Zone of the Andes. A description of Middle-Upper Miocene successions related to explosive- effusive events is presented. The location of this centre close to Cerro Galn Caldera attests a recurrence in the volcanism between 12 and 2 Ma in this portion of the Altiplano - Puna Plateau.

Flora y vegetación leñosa de los bosques de los Andes en la región de Madidi, La Paz (Bolivia)

OpenAIRE

Fuentes Claros, Alfredo Fernando

2016-01-01

Introducción: La región del Madidi en el noroeste de Bolivia es una de las más biodiversas del mundo, por incluir un amplio rango altitudinal desde los 200 hasta más de 6000 m, y floras de los Andes y la Amazonía, dos de las regiones biogeográficas más diversas del mundo. Esta región comprende territorios de tres áreas protegidas de interés nacional (Madidi, Apolobamba y Pilón Lajas), superpuestas a comunidades indígenas, campesinas, y áreas de exploración hidrocarburífera, lo cual ha generad...

Cold Episodes, Their Precursors and Teleconnections in the Central Peruvian Andes (1958-2009)

Science.gov (United States)

Sulca, J. C.; Vuille, M. F.; Trasmonte, G.; Silva, Y.; Takahashi, K.

2014-12-01

The Mantaro valley (MV) is located in the central Peruvian Andes. Occasionally, cold episodes are observed during the austral summer (January-March), which strongly damage crops. However, little is known about the causes and impacts of such cold episodes in the MV. The main goal of this study is thus to characterize cold episodes in the MV and assess their large-scale circulation and teleconnections over South America (SA) during austral summer. To identify cold events in the MV daily minimum temperature for the period 1958-2009 from Huayao station, located within the MV was used. We defined a cold episode as the period when daily minimum temperature drops below the 10-percentile for at least one day. Several gridded reanalysis and satellite products were used to characterize the large-scale circulation, cloud cover and rainfall over SA associated with these events for same period. Cold episodes in the MV are associated with positive OLR anomalies, which extend over much of the central Andes, indicating reduced convective cloud cover during these extremes, but also affirm the large-scale nature of these events. At the same time, northeastern Brazil (NEB) registers negative OLR anomalies, strong convective activity and enhanced cloud cover because displacement of the South Atlantic Convergence Zone (SACZ) toward the northeast of its climatologic position. Further, it is associated with a weakening of the Bolivian High - Nordeste Low (BH-NL) system at upper levels, but also influenced by a low-level migratory high-pressure center develops at 30°S, 50°W; propagating from mid- to low latitudes as part of an extratropical Rossby wave train. In conclusion, cold episodes in the MV appear to be caused by radiative cooling associated with reduced cloudiness, rather than cold air advection. The reduced cloud cover in turn results from a robust large-scale pattern of westerly wind anomalies over central Peruvian Andes, inhibiting moisture influx, convective activity and

Hallazgos citogenéticos en los pacientes de la Unidad de Genética Médica de la Universidad de Los Andes en Mérida, Venezuela

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Dionora Araque

2013-09-01

Full Text Available El siguiente estudio tiene por finalidad identificar los hallazgos citogenéticos en los pacientes de la Unidad de Genética Médica de la Universidad de Los Andes, en Mérida, Venezuela, para determinar la prevalencia y tipo de alteraciones cromosómicas. Se realizó un estudio observacional, descriptivo y de corte transversal, en los pacientes evaluados desde enero de 2005 a enero de 2012. El estudio citogenético fue realizado por técnica convencional de banda G. De un total de 716 estudios citogenéticos realizados, 113 (15,78% presentaron algún tipo de alteración de los cromosomas autosómicos y la trisomía 21 fue la más frecuente con 95 (84,07%; 71 (9,92% de los cromosomas sexuales y la monosomía del X fue la más común con 67 (94,37%. La trisomía 21 constituye el principal tipo de alteración cromosómica en este estudio y los revisados, siendo la trisomía libre la forma más común. La monosomía del X constituye la segunda anormalidad cromosómica y la primera de los cromosomas sexuales, resaltando la alta frecuencia de mosaicismo con una línea celular con monosomía del X y otra línea celular normal. Es pertinente difundir la importancia del análisis citogenético en la práctica médica, como recurso útil en estudio de pacientes con alteraciones cromosómicas. Cytogenetic findings in the patients of the Unit of Medical Genetics University of Los Andes, in Mérida, Venezuela Abstract The following study aims to identify the cytogenetic findings in the patients of the Unit of Medical Genetics of the University of Los Andes in Merida, Venezuela to determine the prevalence and type of chromosomal abnormalities. An observational, descriptive and cross-sectional study was performed in the patients evaluated from january 2005 to january 2012. The cytogenetic study was realized by conventional technique G-banding. A total of 716 of cytogenetic studies performed, 113 (15,78% had some type of alteration of autosomal chromosomes and

Intraseasonal variability of organized convective systems in the Central Andes: Relationship to Regional Dynamical Features

Science.gov (United States)

Mohr, K. I.; Slayback, D. A.; Nicholls, S.; Yager, K.

2013-12-01

The Andes extend from the west coast of Colombia (10N) to the southern tip of Chile (53S). In southern Peru and Bolivia, the Central Andes is split into separate eastern and western cordilleras, with a high plateau (≥ 3000 m), the Altiplano, between them. Because 90% of the Earth's tropical mountain glaciers are located in the Central Andes, our study focuses on this region, defining its zonal extent as 7S-21S and the meridional extent as the terrain 1000 m and greater. Although intense convection occurs during the wet season in the Altiplano, it is not included in the lists of regions with frequent or the most intense convection. The scarcity of in-situ observations with sufficient density and temporal resolution to resolve individual storms or even mesoscale-organized cloud systems and documented biases in microwave-based rainfall products in poorly gauged mountainous regions have impeded the development of an extensive literature on convection and convective systems in this region. With the tropical glaciers receding at unprecedented rates, leaving seasonal precipitation as an increasingly important input to the water balance in alpine valley ecosystems and streams, understanding the nature and characteristics of the seasonal precipitation becomes increasingly important for the rural economies in this region. Previous work in analyzing precipitation in the Central Andes has emphasized interannual variability with respect to ENSO, this is the first study to focus on shorter scale variability with respect to organized convection. The present study took advantage of the University of Utah's Precipitation Features database compiled from 14 years of TRMM observations (1998-2012), supplemented by field observations of rainfall and streamflow, historical gauge data, and long-term WRF-simulations, to analyze the intraseasonal variability of precipitating systems and their relationship regional dynamical features such as the Bolivian High. Through time series and

Compositional data supports decentralized model of production and circulation of artifacts in the pre-Columbian south-central Andes.

Science.gov (United States)

Lazzari, Marisa; Pereyra Domingorena, Lucas; Stoner, Wesley D; Scattolin, María Cristina; Korstanje, María Alejandra; Glascock, Michael D

2017-05-16

The circulation and exchange of goods and resources at various scales have long been considered central to the understanding of complex societies, and the Andes have provided a fertile ground for investigating this process. However, long-standing archaeological emphasis on typological analysis, although helpful to hypothesize the direction of contacts, has left important aspects of ancient exchange open to speculation. To improve understanding of ancient exchange practices and their potential role in structuring alliances, we examine material exchanges in northwest Argentina (part of the south-central Andes) during 400 BC to AD 1000 (part of the regional Formative Period), with a multianalytical approach (petrography, instrumental neutron activation analysis, laser ablation inductively coupled plasma mass spectrometry) to artifacts previously studied separately. We assess the standard centralized model of interaction vs. a decentralized model through the largest provenance database available to date in the region. The results show: ( i ) intervalley heterogeneity of clays and fabrics for ordinary wares; ( ii ) intervalley homogeneity of clays and fabrics for a wide range of decorated wares (e.g., painted Ciénaga); ( iii ) selective circulation of two distinct polychrome wares (Vaquerías and Condorhuasi); ( iv ) generalized access to obsidian from one major source and various minor sources; and ( v ) selective circulation of volcanic rock tools from a single source. These trends reflect the multiple and conflicting demands experienced by people in small-scale societies, which may be difficult to capitalize by aspiring elites. The study undermines centralized narratives of exchange for this period, offering a new platform for understanding ancient exchange based on actual material transfers, both in the Andes and beyond.

Estimation of slip scenarios of mega-thrust earthquakes and strong motion simulations for Central Andes, Peru

Science.gov (United States)

Pulido, N.; Tavera, H.; Aguilar, Z.; Chlieh, M.; Calderon, D.; Sekiguchi, T.; Nakai, S.; Yamazaki, F.

2012-12-01

We have developed a methodology for the estimation of slip scenarios for megathrust earthquakes based on a model of interseismic coupling (ISC) distribution in subduction margins obtained from geodetic data, as well as information of recurrence of historical earthquakes. This geodetic slip model (GSM) delineates the long wavelength asperities within the megathrust. For the simulation of strong ground motion it becomes necessary to introduce short wavelength heterogeneities to the source slip to be able to efficiently simulate high frequency ground motions. To achieve this purpose we elaborate "broadband" source models constructed by combining the GSM with several short wavelength slip distributions obtained from a Von Karman PSD function with random phases. Our application of the method to Central Andes in Peru, show that this region has presently the potential of generating an earthquake with moment magnitude of 8.9, with a peak slip of 17 m and a source area of approximately 500 km along strike and 165 km along dip. For the strong motion simulations we constructed 12 broadband slip models, and consider 9 possible hypocenter locations for each model. We performed strong motion simulations for the whole central Andes region (Peru), spanning an area from the Nazca ridge (16^o S) to the Mendana fracture (9^o S). For this purpose we use the hybrid strong motion simulation method of Pulido et al. (2004), improved to handle a general slip distribution. Our simulated PGA and PGV distributions indicate that a region of at least 500 km along the coast of central Andes is subjected to a MMI intensity of approximately 8, for the slip model that yielded the largest ground motions among the 12 slip models considered, averaged for all assumed hypocenter locations. This result is in agreement with the macroseismic intensity distribution estimated for the great 1746 earthquake (M~9) in central Andes (Dorbath et al. 1990). Our results indicate that the simulated PGA and PGV for

Ingeniería de Sistemas y Computación: Una utopía realizada en la Universidad de los Andes

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2010-12-01

Full Text Available Entre las tarjetas perforadas, las reglas de cálculo, los libros de Fortran y Cobol, y los cursos de algoritmos, sistemas de información y teoría de juegos, los jóvenes Alfredo Amore, Xavier Caicedo y Diego Escobar recibieron el 28 de agosto de 1970 su grado como los primeros Ingenieros de Sistemas y Computación del país. Por la celebración de su aniversario 40, la Revista de Ingeniería se propone hacer memoria sobre el proceso de creación de este programa y sus primeros egresados, pues constituyen un hito determinante en la historia de la ingeniería colombiana, gestado desde la Universidad de los Andes.

Ensayos metodologicos para la investigacion de reservorios de Leishmania spp en los Andes venezolanos Methodological assay for research of reservoirs of Leishmania spp. in the Venezuelan Andes

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Ana Lugo Yarbuh

1982-12-01

Full Text Available Se describen dos técnicas, presuntiva y confirmativa, para la investigación de mamíferos que pudieran ser reservorios de Leishmania que parasitan al hombre. Se investigan los cambios en los títulos de inmovilización y aglutinación de promastigotos de cultivo por los sueros de animales normales y expuestos una o varias veces a la inoculación intradérmica de pequeñas dosis de promastigotos vivos. Se registra una caída de los títulos de aglutinación en los sueros de hamsteres, de Holochilus venezuelae y de Didelphis marsupialis después de la inoculación con L. mexicana mexicana de Panamá y de L. gamhami de la región de los Andes venezolanos. Se discute la natureza de estos fenómenos. Se han hecho xenodiagnósticos con Lutzomyia townsendi en Holochilus venezuelae y Sigmodon hispidus infectados experimentalmente com L. mexicana mexicana, L. mexicana amazonensis, L. braziliensis y L. garnhami. Las pruebas fueron leidas mediante el examen microscópico de las gotitas de heces excretadas entre las 108 y 132 horas después de la ingesta infectante, tras colorearlas con Giemsa. Se obtuvieron resultados positivos en 23% de los experimentos usando mamíferos con lesiones localizadas, dejando a los flebótomos ingurgitarse libremente sobre animales anestesiados que poseian una hasta varias lesiones localizadas.Presumptive and confirmative techniques for searching mammals which could be reservoirs for Leishmania parasites from man are described. The changes of immobilising and agglutinating titers for promastigotes from culture by sera from normal and exposed mammals after single or repeated intradermal inoculation of promastigotes are described. A fall in titers of agglunation is observed in sera from hamsters, Holochilus venezuelae and Didelphis marsupialis after inoculation with L. mexicana mexicana from Panama and L. garnhami from the Venezuelan Andes region. The nature of this phenomenon is discussed. Xenodiagnoses were made with

Ilustración arqueológica en los Andes (1850-1890

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Joanne Pillsbury

Full Text Available Resumen En términos generales, es posible trazar en las publicaciones europeas sobre los Andes una trayectoria histórica en el curso de cuatro siglos, desde un sistema de representación que está íntimamente atado – y afiliado – a la palabra escrita, a uno donde las imágenes se convierten en la razón de ser de la publicación. Esta trayectoria refleja el campo de la arqueología en sí mismo, desde sus orígenes en una tradición de anticuarios dominada por las preocupaciones filológicas durante los siglos XVI y XVII, al siglo XIX, donde las evidencias fotográficas ganan fuerza frente a las escritas. Este documento se centra en el pico de esta trayectoria: los atlas arqueológicos creados entre 1850 y 1890, en particular el trabajo de Wilhelm Reiss y Alphons Stübel y su publicación en tres volúmenes titulada “The necropolis of Ancon in Peru” (“La necrópolis de Ancón en el Perú”. El presente estudio analiza el papel de la ilustración arqueológica en la iluminación, la difusión y comprensión de un pasado pre-inca durante el siglo XIX, y en última instancia, cómo las imágenes dan forma a la construcción del conocimiento.

Aproximaciones Biológicas y Fisicoquímicas en el tratamiento de contaminantes: un resumen del aporte de la Universidad de los Andes

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Jenny Dussan Garzón

2009-11-01

Full Text Available Este resumen pretende dar una visión global de los aportes de la Universidad de los Andes en el tratamiento de aguas y suelos con la presencia de compuestos de difícil degradación o tiempo de vida media prolongado, tales como fármacos (Ciclofosfamida, lodos aceitosos y derivados de la industria del petróleo (Tolueno, Xileno, Fenol derivados de la industria textil, química y pesticidas (Bisphenol A, AMBI, Glifosato, Isoproturon y Metobromuron, usando tecnologías ya sea basadas en procesos biológicos (biorremediación y bioadsorción o de oxidación avanzada (foto-Fenton. /This summary intends to give a global view of the Universidad de los Andes contributions related to the water and soil treatment in the presence of recalcitrant or long half-life aquatic pollutants such as drugs (Cyclophosphamide, oil sludge and petroleum (Toluene, Xylene and Phenol, textile, chemical (Bisphenol A, AMBI and pesticides (Glyphosate, Isoproturon, and Metobromuron industry derived products based on biological (bioremediation and bioadsortion and advanced oxidation (Photo-Fenton approaches.

Andes 1997 Gravity Data

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National Oceanic and Atmospheric Administration, Department of Commerce — The Central Andes gravity data (6,151 records) were compiled by Professor Gotze and the MIGRA Group. This data base was received in April, 1997. Principal gravity...

Culture and landslide risk in the Central Andes of Bolivia and Peru

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Nicholas Roberts

2009-06-01

Full Text Available Culture and its heritage play a major role in determining landslide risk in the Central Andes. Examples of some of these many possible influences are provided from natural and social science literature and from the author’s recent work in Bolivia. Landslide risk appears to have generally increased throughout the last millennium, due largely to anthropogenic modification of hazard, exposure, vulnerability and coping capacity. These changes result from both local and distant pressures and from contemporaneous and pervious cultural factors. Consequently, holistic examination of landslide risk necessitates consideration of culture and its heritage.

Categorías conceptuales sobre la producción y gerencia del conocimiento en la Universidad de los Andes (ULA)

OpenAIRE

Rincón de Parra, Haydeé Cecilia; Briceño, Magally

2008-01-01

Esta investigación presenta como objetivo construir categorías conceptuales, a partir de lo expresado por un grupo de diez profesores-investigadores, sobre la forma en que se gerencia el proceso de producción de conocimiento en la Universidad de Los Andes. Para la recogida y análisis de los datos se consideraron algunos lineamientos de la Teoría Fundamentada. Se construyeron cinco categorías conceptuales: a) producción de conocimiento, b) filosofía del conocimiento como sustento, c) difusión ...

Genome of Plant Maca (Lepidium meyenii) Illuminates Genomic Basis for High-Altitude Adaptation in the Central Andes.

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Zhang, Jing; Tian, Yang; Yan, Liang; Zhang, Guanghui; Wang, Xiao; Zeng, Yan; Zhang, Jiajin; Ma, Xiao; Tan, Yuntao; Long, Ni; Wang, Yangzi; Ma, Yujin; He, Yuqi; Xue, Yu; Hao, Shumei; Yang, Shengchao; Wang, Wen; Zhang, Liangsheng; Dong, Yang; Chen, Wei; Sheng, Jun

2016-07-06

Maca (Lepidium meyenii Walp, 2n = 8x = 64), belonging to the Brassicaceae family, is an economic plant cultivated in the central Andes sierra in Peru (4000-4500 m). Considering that the rapid uplift of the central Andes occurred 5-10 million years ago (Ma), an evolutionary question arises regarding how plants such as maca acquire high-altitude adaptation within a short geological period. Here, we report the high-quality genome assembly of maca, in which two closely spaced maca-specific whole-genome duplications (WGDs; ∼6.7 Ma) were identified. Comparative genomic analysis between maca and closely related Brassicaceae species revealed expansions of maca genes and gene families involved in abiotic stress response, hormone signaling pathway, and secondary metabolite biosynthesis via WGDs. The retention and subsequent functional divergence of many duplicated genes may account for the morphological and physiological changes (i.e., small leaf shape and self-fertility) in maca in a high-altitude environment. In addition, some duplicated maca genes were identified with functions in morphological adaptation (i.e., LEAF CURLING RESPONSIVENESS) and abiotic stress response (i.e., GLYCINE-RICH RNA-BINDING PROTEINS and DNA-DAMAGE-REPAIR/TOLERATION 2) under positive selection. Collectively, the maca genome provides useful information to understand the important roles of WGDs in the high-altitude adaptation of plants in the Andes. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Poder y sociedad en los Andes: Manuel Isidoro Belzu, un caudillo popular. Bolivia, 1848-1855

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Luis Javier Ortíz Mesa

1995-01-01

Full Text Available En este ensayo quiero referirme a un gobernante boliviano, Manuel Isidoro Belzu, presidente entre los años de 1848 y 1855. Con una larga carrera militar de casi 25 años, en un ambiente de permanente inestabilidad política y con una fascinante estrategia, Belzu ha sido percibido por algunos historiadores y literatos como un «Caudillo del Pueblo», otros lo calificaron como un demagogo y algunos más como el presidente para la Bolivia de entonces. Manuel Isidoro Belzu nació al tiempo que se vislumbraba la Bolivia Republicana en 1808. Fue un hombre pobre como muchos de sus conciudadanos, predominantemente indígenas. No obstante, Belzu fue un mestizo, expresión de los cambios raciales que desde la Colonia se produjeron en la población de la Audiencia de Charcas cuya sede y capital fue Chuquisaca o Sucre, donde tuvo asiento el emporio minero más importante y productivo de los Andes, el Cerro Rico de Potosí.

Una nueva especie de Lepidoblepharis (Sauria, Gekkonidae de la Cordillera Central de Colombia Una nueva especie de Lepidoblepharis (Sauria, Gekkonidae de la Cordillera Central de Colombia

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Ayala Stephen C.

1986-12-01

Full Text Available A third Lepidoblepharis is described from temperate elevations in the Colombian Andes. Unlike L. colombianus or L. duolepis, the new species from central Antioquia is a small, moderately short toed species, reaching about 30 mm snout-vent length. Most specimens have prominent rust colored dorsolateral stripes on the tail. Una tercera especie de Lepidoblepharis se describe de zonas templadas de los Andes de Colombia. A diferencia de L. colombianus o L. duolepis, la nueva especie de Antioquia es una especie de menor tamaño que alcanza unos 30 mm de longitud rostro-ano, y los dedos son moderadamente cortos. La mayoría de los ejemplares tiene franjas dorsolaterales muy notorias de color herrumbre en la cola.

EFECTO DE LA EXTRACCIÓN DE RAÍCES AÉREAS SOBRE LAS POBLACIONES DE “TRIPEPERRO” (PHILODENDRON LONGIRRHIZUM, ARACEAE EN LOS ANDES CENTRALES DE COLOMBIA

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García Nestor

2009-06-01

Full Text Available El "tripeperro" (Philodendron longirrhizum es una planta hemiepífi ta de ampliadistribución en Los Andes de Colombia. En la región del Eje Cafetero colombiano seemplean las raíces aéreas de esta especie como fi bra para elaborar canastos y artesanías.Esta actividad tiene una larga tradición en la región y se concentra en el municipiode Filandia (departamento del Quindío. En los últimos años se ha presentado unadisminución en la oferta de raíces adecuadas para la actividad artesanal en todas lasáreas donde tradicionalmente se obtiene el "tripeperro". Se evaluó el efecto de laextracción sobre la estructura de tamaños, la densidad y el rendimiento de las raíces,comparando poblaciones en áreas con extracción del recurso con poblaciones enáreas sin extracción. Los resultados indican que, aunque la extracción parece noafectar la densidad poblacional, sí tiene efectos signifi cativos sobre la estructura detamaños y, en consecuencia, sobre el rendimiento de las raíces. La disponibilidad deeste recurso en las áreas con extracción es hasta cinco o seis veces menor que en delas áreas sin extracción.

TÉCNICAS DE LIQUENOMETRÍA BASADAS EN RHIZOCARPON SUBGÉNERO RHIZOCARPON PARA DATAR DEPÓSITOS GLACIARES EN LOS ANDES PATAGÓNICOS

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Irene Garibotti

2007-12-01

Full Text Available La liquenometría es una técnica de datación que estima la edad de exposición de una superficie a partir del diámetro de los líquenes que crecen en ella. El objetivo de este estudio es calibrar la curva de crecimiento de Rhizocarpon subgénero Rhizocarpon en los Andes Patagónicos, y aplicarla para reconstruir las fluctuaciones glaciares durante los últimos siglos. Para ello se investigaron seis glaciares, tres en el norte y tres en el sur de los Andes Patagónicos, en los cuales se realizaron mediciones del diámetro de ejemplares del subgénero Rhizocarpon en sitios de edad conocida (sitios control y sitios de edad desconocida. La edad de los sitios control se determinó fehacientemente a partir de información histórica. Los datos liquenométricos relevados en estos sitios control fueron utilizados para calibrar la curva de crecimiento. La relación entre el tamaño de los líquenes y la edad de la superficie (curva de crecimiento es lineal, indicando que los líquenes del subgénero Rhizocarpon tienen una tasa de crecimiento constante a lo largo del tiempo. Esta curva se extiende por 270 años. Aplicación de la curva a los datos liquenométricos relevados en las morenas de edad desconocida permitió establecer la cronología de la secuencia de morenas de los seis glaciares bajo estudio. Los datos liquenométricos fueron contrastados con datos dendrocronológicos, mostrando una gran concordancia entre los métodos. Los resultados obtenidos muestran dos períodos principales de formación de morenas. El primer período se extiende desde la mitad del siglo XVII hasta finales del siglo XIX, y está caracterizado por morenas muy prominentes. El segundo período se extiende desde mediados del siglo XIX hasta finales del siglo XX, y esta caracterizado por la formación de un gran número de morenas pequeñas.

Recursos hídricos en los Andes: Lago Titicaca

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1995-01-01

Full Text Available RESSOURCES EN EAUX DANS LES ANDES : LAC TITICACA. Une analyse par régression a été menée entre les variations de niveau du Lac Titicaca et les entrées du système (apports des affluents et précipitations. Les coefficients de corrélation, quoique relativement faibles, montrent aux abords du lac un effet de persistance qui diminue lorsque les stations sont éloignées du plan d’eau. L’inertie du lac se manifeste l’année suivante pour les affluents du lac et évidemment pour le lac lui-même. Ces résultats confirment la présence d’un mécanisme de rétro alimentation (effet boomerang. Cela montre que le système du Lac Titicaca est fragile, face à une utilisation excessive de ses eaux. Las regresiones estudiadas de cambios de nivel en el lago Titicaca contra precipitaciones y aportes en su cuenca, aunque relativamente bajas, muestran un efecto de persistencia en las proximidades del lago que decrece conforme las estaciones se alejan de éste. Lo que evidencia que la inercia del lago se manifiesta en el período siguiente (lag uno en los afluentes del lago y obviamente en el propio lago, fenómeno que parece confirmar la presencia de un mecanismo de retroalimentación (efecto boomerang. Este comportamiento muestra la fragilidad del lago frente a un aprovechamiento consuntivo excesivo. WATER RESOURCES IN THE ANDES: LAKE TITICACA. The studied regressions of the level changes in the Lake Titicaca versus the rainfall and the runoff in the basin, even being relatively low, show an effect of persistence in the proximity of the lake which decreases as we go away from it. This makes evident that the lake inertia manifests itself the following period (lag one in the lake tributaries and obviously in the lake itself, phenomenon which seems to confirm the presence of a feedback mechanism (boomerang effect. This behaviour shows the fragility of the lake against the excessive consumptive uses of the waters in its basin.

Population dynamics of the rat Microryzomys minutus (Rodentia: Muridae in the Venezuelan Andes

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Daniel R Cabello

2006-06-01

Full Text Available The population dynamics of the small forest rice rat Microryzomys minutus, a murid rodent that occurs in the high altitudes of the northern and central Andes, was studied in disturbed and primary environments in a cloud forest of the Venezuelan Andes (Juan Pablo Peñaloza National Park, 8º11’N, 71º49’W. We collected 121 animals (66♀♀ and 55♂♂ between 1995 and 1998, using pitfall traps with formalin. Adult males were heavier than adult females. Relative abundance was much greater in the disturbed environments (over 10 individuals in some periods than in the primary cloud forest: 4-8 individuals. In the disturbed environments, the rats were extremely abundant in the first sampling period, and less frequent afterwards. In the cropland, abundance showed some fluctuations during the study and displayed two small abundance peaks in March-June 1997 and 1998. In the mined area, the rats had irregular fluctuations until March-June 1997 and were not recorded in July-October 1997. The occurrence of this rat in both disturbed and natural habitats confirms the wide ecological tolerance of this species. Rev. Biol. Trop. 54(2: 651-. Epub 2006 Jun 01.Se analizó la dinámica poblacional de las pequeñas ratas silvestres del arroz Microryzomys minutus en ambientes alterados y primarios, en un bosque nublado de los Andes venezolanos. El estudio fue basado en 121 animales (66♀♀ y 55♂♂ recolectados entre 1995 y 1998, usando trampas que contenían formalina. Esta especie está presente en ambos hábitats lo que confirma su amplia tolerancia ecológica. La abundancia poblacional fue mayor en ambientes alterados que en los no alterados. M. minutus presenta dimorfismo sexual en el peso: los machos son más pesados que las hembras.

Climate in the Western Cordillera of the Central Andes over the last 4300 years

Science.gov (United States)

Engel, Zbyněk; Skrzypek, Grzegorz; Chuman, Tomáš; Šefrna, Luděk; Mihaljevič, Martin

2014-09-01

The Distichia peat core obtained in the Carhuasanta valley near Nevado Mismi, Cordillera Chila, provides information on climatic and environmental conditions over the last ˜4300 years. The relative changes in the stable carbon isotope composition of plant remains preserved in the core reflect major temperature fluctuations in the Western Cordillera of the southern Peruvian Andes. These temperature variations can be additionally linked with the changes in precipitation patterns by analysing C% and C/N ratio in the core. Relatively warm and moist conditions prevailed from 4280 to 3040 cal. yrs BP (BC 2330-1090) with a short colder dry episode around 3850 cal. yrs BP (BC 1900). The most prominent climate changes recorded in the peat occurred between 3040 and 2750 cal. yrs BP (BC 1090-800) when the initial warming turned to a rapid cooling to temperatures at least 2 °C lower than the mean for the Late Holocene. Initially drier conditions within this event turned to a short wet phase after 2780 cal. yrs BP (BC 830) when the temperature increased again. This event coincides with significant changes in peat and ice core records in the Central Andes matching the timing of the global climate event around 2.8 cal. ka BP. Climatic conditions in the study area became relatively dry and stable after the event for about 800 years. Highly variable temperatures and humidity prevailed during the last 2000 years when an extended warm and relatively humid period occurred between 640 and 155 cal. yrs BP (AD 1310-1795) followed by predominantly colder and drier conditions. The established δ13C peat record represents the first continuous proxy for the temperature in the southern Peruvian Andes dated by the AMS 14C. Distichia peat is wide spread in the Andes and the proposed approach can be applied elsewhere in high altitudes, where no other traditional climate proxies are available.

Impact of Santiago de Chile urban atmospheric pollution on anthropogenic trace elements enrichment in snow precipitation at Cerro Colorado, Central Andes

Science.gov (United States)

Cereceda-Balic, F.; Palomo-Marín, M. R.; Bernalte, E.; Vidal, V.; Christie, J.; Fadic, X.; Guevara, J. L.; Miro, C.; Pinilla Gil, E.

2012-02-01

Seasonal snow precipitation in the Andes mountain range is evaluated as an environmental indicator of the composition of atmospheric emissions in Santiago de Chile metropolitan area, by measuring a set of representative trace elements in snow samples by ICP-MS. Three late winter sampling campaigns (2003, 2008 and 2009) were conducted in three sampling areas around Cerro Colorado, a Central Andes mountain range sector NE of Santiago (36 km). Nevados de Chillán, a sector in The Andes located about 500 km south from the metropolitan area, was selected as a reference area. The experimental results at Cerro Colorado and Nevados de Chillán were compared with previously published data of fresh snow from remote and urban background sites. High snow concentrations of a range of anthropogenic marker elements were found at Cerro Colorado, probably derived from Santiago urban aerosol transport and deposition combined with the effect of mining and smelting activities in the area, whereas Nevados de Chillán levels roughly correspond to urban background areas. Enhanced concentrations in surface snow respect to deeper samples are discussed. Significant differences found between the 2003, 2008 and 2009 anthropogenic source markers profiles at Cerro Colorado sampling points were correlated with changes in emission sources at the city. The preliminary results obtained in this study, the first of this kind in the southern hemisphere, show promising use of snow precipitation in the Central Andes as a suitable matrix for receptor model studies aimed at identifying and quantifying pollution sources in Santiago de Chile.

Novel Strain of Andes Virus Associated with Fatal Human Infection, Central Bolivia

Science.gov (United States)

Cruz, Cristhopher D.; Vallejo, Efrain; Agudo, Roberto; Vargas, Jorge; Blazes, David L.; Guevara, Carolina; Laguna-Torres, V. Alberto; Halsey, Eric S.; Kochel, Tadeusz J.

2012-01-01

To better describe the genetic diversity of hantaviruses associated with human illness in South America, we screened blood samples from febrile patients in Chapare Province in central Bolivia during 2008–2009 for recent hantavirus infection. Hantavirus RNA was detected in 3 patients, including 1 who died. Partial RNA sequences of small and medium segments from the 3 patients were most closely related to Andes virus lineages but distinct (1 hantaviruses; the highest prevalence was among agricultural workers. Because of the high level of human exposure to hantavirus strains and the severity of resulting disease, additional studies are warranted to determine the reservoirs, ecologic range, and public health effect of this novel strain of hantavirus. PMID:22515983

Cuando ya no se puede tomar trago ni chacchar coca. When alcohol can no longer be drunk or coca leaves chewed. the case of the “protestants” in the Peruvian central Andes

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Caroline Magny

2009-12-01

Full Text Available Desde hace mucho tiempo el alcohol y la coca ocupan un lugar central en las comunidades andinas. Hasta ahora en el distrito de Churcampa (Huancavelica, Perú, los católicos, mayoritarios, siguen explicando al visitante lo siguiente: “acá no se puede hacer nada sin trago ni coca”. No obstante, durante las ultimas décadas, muchas personas en este distrito – así como en muchos otros distritos de los Andes peruanos – se han convertido y siguen convirtiéndose al “protestantismo” (termino genérico usado por los católicos para referirse en forma general a las Iglesias evangélicas. Esta conversión implica, entre otras cosas, dejar completamente de masticar hojas de coca y de beber cualquier tipo de bebidas alcohólicas. En esta exposición proponemos analizar hasta qué punto y bajo qué modalidades estas restricciones alimenticias afectan a los conversos (quienes siguen siendo minoritarios en el distrito en su vida social cotidiana.Alcohol and coca have played a central role in Andean communities for many centuries. Nowadays, in the district of Churcampa (Huancavelica, Peru, the Catholic people, who are the majority, still explain to visitors that “here you can’t do anything without trago [alcohol] and coca”. Yet, over the past decades, many men and women in this district - as well as in many other districts of the Peruvian Andes - have been converting to “Protestantism” (a generic term used by Catholics to refer to the Evangelical Churches. This conversion implies, among other things, completely giving up chewing of coca leaves and drinking of any type of alcoholic drink. The aim of this article is to analyze to what extent and how these restrictions in the dietary habits affect converted people in their everyday social life.alcohol, coca leaves, religion, conversion, evangelic Churches, Peru

Spatio-Temporal Patterns of the 2010–2015 Extreme Hydrological Drought across the Central Andes, Argentina

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Juan Antonio Rivera

2017-08-01

Full Text Available During the period 2010–2015, the semi-arid Central Andes in Argentina (CAA experienced one of the most severe and long-lasting hydrological droughts on record. Since the snowmelt is the most important source of water, the reduced snowfall over the mountains propagated the drought signal through the streamflows in the adjacent foothills east of the Andes ranges. Motivated by the widespread impacts on the socio-economic activities in the region, this study aims to characterize the recent hydrological drought in terms of streamflow deficits. Based on streamflow data from 20 basins, we used the standardized streamflow index (SSI to characterize hydrological droughts during the period 1971–2016. We found that the regional extent of the 2010–2015 hydrological drought was limited to the basins located north of 38° S, with mean duration of 67 months and maximum drought severity exhibiting a heterogeneous pattern in terms of spatial distribution and time of occurrence. The drought event reached extreme conditions in 14 of the 15 basins in the CAA, being record-breaking drought in six of the basins. This condition was likely driven by a cooling in the tropical Pacific Ocean resembling La Niña conditions, which generated a decrease in snowfall over the Andes due to suppressed frontal activity.

Influence of spatial resolution on precipitation simulations for the central Andes Mountains

Science.gov (United States)

Trachte, Katja; Bendix, Jörg

2013-04-01

The climate of South America is highly influenced by the north-south oriented Andes Mountains. Their complex structure causes modifications of large-scale atmospheric circulations resulting in various mesoscale phenomena as well as a high variability in the local conditions. Due to their height and length the terrain generates distinctly climate conditions between the western and the eastern slopes. While in the tropical regions along the western flanks the conditions are cold and arid, the eastern slopes are dominated by warm-moist and rainy air coming from the Amazon basin. Below 35° S the situation reverses with rather semiarid conditions in the eastern part and temperate rainy climate along southern Chile. Generally, global circulation models (GCMs) describe the state of the global climate and its changes, but are disabled to capture regional or even local features due to their coarse resolution. This is particularly true in heterogeneous regions such as the Andes Mountains, where local driving features, e. g. local circulation systems, highly varies on small scales and thus, lead to a high variability of rainfall distributions. An appropriate technique to overcome this problem and to gain regional and local scale rainfall information is the dynamical downscaling of the global data using a regional climate model (RCM). The poster presents results of the evaluation of the performance of the Weather Research and Forecasting (WRF) model over South America with special focus on the central Andes Mountains of Ecuador. A sensitivity study regarding the cumulus parametrization, microphysics, boundary layer processes and the radiation budget is conducted. With 17 simulations consisting of 16 parametrization scheme combinations and 1 default run a suitable model set-up for climate research in this region is supposed to be evaluated. The simulations were conducted in a two-way nested mode i) to examine the best physics scheme combination for the target and ii) to

Tectonics, hydrothermal zoning, and uranium in the central Andes

Energy Technology Data Exchange (ETDEWEB)

Gabelman, J W

1961-01-01

The geological features of the Peruvian Andes are discussed in some detail. The geologic history of the Andrean tectonics was found to be virtually the same as that represented in both North and South American Cordillera. The study indicated that Andrean hydrothermal mineralization occurred intermittently but in close time relation with accompanying deformations from the late Cretaceous or early Tertiary up to the present. The mineralization cycle is discussed as it relates to several metals, particularly uranium. Uranium is believed to occupy the same several temperature--environmental positions in the Andes that it does throughout the rest of the western hemisphere Cordillera. Even though uranium is present in minor quantities in several high-to-moderate-temperature environments, the bulk of uranium present in the cycle is believed to precipitate in the subepithermal environment.

Extreme hydrometeorological events in the Peruvian Central Andes during austral summer and their relationship with the large-scale circulation

Science.gov (United States)

Sulca, Juan C.

In this Master's dissertation, atmospheric circulation patterns associated with extreme hydrometeorological events in the Mantaro Basin, Peruvian Central Andes, and their teleconnections during the austral summer (December-January-February-March) are addressed. Extreme rainfall events in the Mantaro basin are related to variations of the large-scale circulation as indicated by the changing strength of the Bolivian High-Nordeste Low (BH-NL) system. Dry (wet) spells are associated with a weakening (strengthening) of the BH-NL system and reduced (enhanced) influx of moist air from the lowlands to the east due to strengthened westerly (easterly) wind anomalies at mid- and upper-tropospheric levels. At the same time extreme rainfall events of the opposite sign occur over northeastern Brazil (NEB) due to enhanced (inhibited) convective activity in conjunction with a strengthened (weakened) Nordeste Low. Cold episodes in the Mantaro Basin are grouped in three types: weak, strong and extraordinary cold episodes. Weak and strong cold episodes in the MB are mainly associated with a weakening of the BH-NL system due to tropical-extratropical interactions. Both types of cold episodes are associated with westerly wind anomalies at mid- and upper-tropospheric levels aloft the Peruvian Central Andes, which inhibit the influx of humid air masses from the lowlands to the east and hence limit the potential for development of convective cloud cover. The resulting clear sky conditions cause nighttime temperatures to drop, leading to cold extremes below the 10-percentile. Extraordinary cold episodes in the MB are associated with cold and dry polar air advection at all tropospheric levels toward the central Peruvian Andes. Therefore, weak and strong cold episodes in the MB appear to be caused by radiative cooling associated with reduced cloudiness, rather than cold air advection, while the latter plays an important role for extraordinary cold episodes only.

Preliminary Results From the CAUGHT Experiment: Investigation of the North Central Andes Subsurface Using Receiver Functions and Ambient Noise Tomography

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Ryan, J. C.; Ward, K. M.; Porter, R. C.; Beck, S. L.; Zandt, G.; Wagner, L. S.; Minaya, E.; Tavera, H.

2011-12-01

Jamie Ryan, Kevin M. Ward, Ryan Porter, Susan Beck, George Zandt, Lara Wagner, Estela Minaya, and Hernando Tavera The University of Arizona The University of North Carolina San Calixto Observatorio, La Paz, Bolivia IGP, Lima, Peru In order to investigate the interplay between crustal shortening, lithospheric removal, and surface uplift we have deployed 50 broadband seismometers in northwestern Bolivia and southern Peru as part of the interdisciplinary Central Andean Uplift and Geodynamics of High Topography (CAUGHT) project. The morphotectonic units of the central Andes from west to east, consist of the Western Cordillera, the active volcanic arc, the Altiplano, an internally drained basin (~4 km elevation), the Eastern Cordillera, the high peaks (~6 km elevation) of an older fold and thrust belt, the Subandean zone, the lower elevation active fold and thrust belt, and the foreland Beni basin. Between northwestern Bolivia and southern Peru, the Altiplano pinches out north of Lake Titicaca as the Andes narrow northward. The CAUGHT seismic instruments were deployed between 13° to 18° S latitudes to investigate the crust and mantle lithosphere of the central Andes in this transitional zone. In northwest Bolivia, perpendicular to the strike of the Andes, there is a total of 275 km of documented upper crustal shortening (15° to 17°S) (McQuarrie et al, 2008). Associated with the shortening is crustal thickening and possibly lithospheric removal as the thickening lithospheric root becomes unstable. An important first order study is to compare upper crustal shortening estimates with present day crustal thickness. To estimate crustal thickness, we have calculated receiver functions using an iterative deconvolution method and used common conversion point stacking along the same profile as the geologically based shortening estimates. In our preliminary results, we observed a strong P to S conversion corresponding to the Moho at approximately 60-65 km depth underneath the

Patrones de diversidad alfa en tres fragmentos de bosques montanos en la región norte de los Andes, Colombia

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Wilson López

2010-03-01

Full Text Available En el presente trabajo se analizaron los patrones de diversidad alfa en tres áreas protegidas de bosque con base en información florística proveniente de seis parcelas permanentes de 1ha -dos en cada área protegida-. Las regiones de estudio están localizadas a lo largo de un gradiente altitudinal, en la parte norte de la cordillera central de los Andes, Colombia. Para los análisis, se generaron dos categorías de acuerdo al tamaño de los árboles: dosel (diámetro a la altura del pecho mayor o igual a 10cm y sotobosque (diámetro a la altura del pecho mayor o igual a un cm y menor a 10cm. Las curvas especies-área mostraron diferencias en riqueza para las dos categorías de tamaño en las tres regiones. Las curvas especies-individuos, en cambio, fueron independientes con respecto al tamaño de los individuos, excepto en la región de Belmira. La diversidad, medida con el índice alfa de Fisher, mostró una fuerte tendencia a la estabilización en muestras mayores a 1 000 individuos. Ni las curvas de especies-área ni las de especies-individuos fueron asintóticas; sin embargo, la tasa de acumulación de especies (z en Belmira alcanzó valores muy bajos (0.05 en comparación con Anorí y Angelópolis (0.25 en cada caso. El índice alfa de Fisher permitió además entender la magnitud de las diferencias relativas en diversidad entre regiones o tipos de bosque en gradientes altitudinales, aun cuando el tamaño de la muestra fue relativamente pequeño. Los resultados de este estudio soportan la limitación en dispersión como el principal mecanismo en estructurar las comunidades de especies a escalas muy finas, y un incremento continuo de procesos denso-dependientes en determinar la estructura de la comunidad en escalas espaciales más grandes. Igualmente, los resultados de este estudio proponen que la denso-dependencia tiende a aumentar positivamente con la altitud.Alpha diversity patterns in three fragmented forests of Northern Andes

Calcite Twin Analysis in the Central Andes of Northern Argentina and Southern Bolivia

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Hardesty, E.; Hindle, D.

2005-12-01

The use of calcite twinning to infer compression directions and strain axes patterns has been applied widely in both fold and thrust belts, and continental interiors. Calcite twinning is noted to be one of the most precise methods for determining the internal strain of deformed rocks. Until now, such data from the deformed plate boundary of the Central Andes were lacking. This study has examined twinning orientations along the deformed Andean foreland (southern Bolivia and northern Argentina) from -25 to -20 latitude. In the Central Andes, we find an abundance of calcite twins in intervals of the Cretaceous age Yacorite limestone. Twin samples were collected, measured for orientation and type (I and II can be best used for strain analysis), and processed using the Groshong method, to give resultant strain tensors. The orientations of the twin short axes trend mostly NE-SW, which is close to the plate convergence direction. However, in a limited number of samples from the north, adjacent to the southern culmination of the active Subandean fold thrust belt, they trend NW-SE. This difference may be related to the more active, or more recent, shortening of the southern portion of the Eastern Cordillera, south of the culmination of the Subandean belt. This implies that twin short axes vary consistently with respect to geographic location and local tectonic regime. NW-SE trends in the northern region match well with fault kinematic studies in rocks pre-dating the San Juan del Oro unconformity (9-10 Ma). NE-SW trends in the south could correspond to much younger (~1-3 Ma) fault kinematic trends. In the Eastern Cordillera, where there is present day tectonic activity, the plunges of the twin short axes are found to be almost horizontal. This suggests that the twins were formed after folding occurred.

Reabsorción de nitrógeno y fósforo foliar en árboles de bosques montanos en los Andes centrales de Colombia

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Miguel Vera

1999-06-01

Full Text Available Se determinaron las concentraciones y los porcentajes de reabsorción de nitrógeno y fósforo foliar en cinco especies de árboles de un bosque montano bajo (BMB a 1850 m.s.n.m. y en cinco de un bosque montano alto (BMA a 2800 m.s.n.m en la Cordillera Central colombiana, asi como la disponibilidad de nitrógeno y fósforo del suelo. Los porcentajes de reabsorción de N y P no fueron significativamente diferentes entre las especies de estos dos bosques. A pesar de esto, se observó que la reabsorción de P foliar tendió a ser mayor en las especies del BMB donde la concentración de P en el suelo fue significativamente más baja (3.2 ppm vs. 9.0 ppm. Cuando la reabsorción de P foliar se expresó como función de la concentración en hojas maduras en 12 tipos de bosques montanos tropicales, se encontró una correlación negativa y estadísticamente significativa. Estos resultados sugieren que los porcentajes de reabsorción de P foliar en bosques montanos estarían controlados parcialmente por la disponibilidad del elemento.Mature leaves and litterfall were collected between November 1992 and February 1993 from one to three individuals of five canopy tree species of a lower montane rain forest (LMRF at 1850 m. and five canopy tree species of an upper montane rain forest (UMRF at 2800 m. in the Central Andes of Colombia, to determine the concentrations and percentage retranslocation of nitrogen and phosphorus. The availability of these two nutrients was measured in the soils, by means of extracts of NH3-NH4, NO2-NO3 and PO4, and incubations of surface soil samples (0-10 cm to measure the rates of nitrogen mineralization and nitrification. In the species of the LMRF the average concentration of N in mature leaves (1.19 % dry weight and litterfall (0.87 % was significantly higher than in mature leaves (0.90 % and litterfall (0.59 % of the tree species of the UMRF. Percentage retranslocation of N and P were not significantly different between the

APROPIACIÓN INCA EN LA CORDILLERA DE CHILLA, SUROESTE DE LOS ANDES DEL ECUADOR: EL CASO DEL SITIO GUIÑAYZHU (Inca Appropriation in the Chilla Mountain Range, Southwest of the Andes of Ecuador: the Case of the Guiñayzhu Site

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Mary Jadán V.

2018-03-01

Full Text Available En este artículo se discuten los resultados del trabajo realizado en el sitio Guiñayzhu, al suroeste de los Andes del Ecuador. Esta investigación revela que el sitio, además de presentar evidencias de poblaciones locales, tiene colcas o qullcas para el almacenaje de productos, terrazas de pirca y caminos empedrados entre otras instalaciones. Se interpreta que Guiñayzhu es uno de los sitios de la cordillera de Chilla que refleja la expansión del incario y expresa una efectiva dominación de esta región como un enclave estratégico del imperio en su avance hacia el norte. ENGLISH: In this article, the results of research carried out in Guiñayzhu, located at the southwest of the Andes of Ecuador, are discussed. This work reveals that in addition to presenting evidence of local populations, the site has colcas or qullqas for the storage of products, terraces of pirca, and roads paved with stone, among other constructions. Guiñayzhu is interpreted as one of the sites of the Chilla mountain range that reflects the expansion of the Inca and expresses an effective domination of this region, representing a strategic enclave of the empire in its advance northward.

Breeding system of Embothrium coccineum (Proteaceae in two populations on different slopes of the Andes Sistema reproductivo de Embothrium coccineum (Proteaceae en dos poblaciones ubicadas en diferentes laderas de los Andes

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ADRIANA E ROVERE

2006-06-01

Full Text Available Plant breeding systems are considered to reflect species' life history characteristics, selection due to biotic or abiotic factors, pollination conditions, or a combination of these. Reproductive systems may vary over ecological gradients. The breeding system of the ornithophilous Embothrium coccineum (Proteaceae from temperate South America was studied by pollination treatments: manual self-pollination, manual cross-pollination, automatic self-pollination, and natural pollination. These treatments were conducted in a coastal western and an Andean eastern population. Embothrium coccineum was found to be self-incompatible and highly dependent on the pollinating agent at both sites. However, pollen limitations were greater in the coastal population, as breeding efficiency was lower. Populations have different floral visitors whose identity differentially affects reproductive efficiency and pollen flow in E. coccineumLos sistemas de compatibilidad reproductiva en las plantas son considerados una manifestación de la historia de vida, de la selección ante factores abióticos ó bióticos, de las condiciones de polinización o una de combinación de esos factores. El sistema reproductivo de una especie puede variar a lo largo de un gradiente ecológico-ambiental. El sistema reproductivo de Embothrium coccineum (Proteaceae, un árbol ornitófilo endémico de los bosques templados de sur de Sudamérica, fue estudiado mediante experimentos de polinización: autopolinización manual, polinización manual cruzada, autopolinización automática y polinización natural en flores descubiertas. Este trabajo se realizó en una población costera al oeste de la cordillera de los Andes y una población andina ubicada al este de la cordillera de los Andes. En ambas poblaciones se encontró que E. coccineum es autoimcompatible y altamente dependiente de los agentes polinizadores en ambos sitios. Sin embargo, la limitación por polen fue mayor en la poblaci

Cold episodes in the Peruvian Central Andes: Composites, Types, and their Impacts over South America (1958-2014)

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Sulca, J. C.; Vuille, M. F.; Roundy, P. E.; Trasmonte, G.; Silva, Y.; Takahashi, K.

2015-12-01

The Mantaro basin (MB) is located in the central Peruvian Andes. Occasionally, cold episodes are observed during austral summer (January-March), that strongly damage crops. However, little is known about the causes and impacts of such cold episodes. The main goal of this study is thus to characterize cold episodes in the MB and assess their large-scale circulation and teleconnections over South America (SA) during austral summer. To identify cold events in the MB daily minimum temperature (Tmin) for the period 1958-2014 from Huayao station, located within the MB was used. A cold episode is defined when daily minimum temperature drops below its 10-percentile for at least one day. Additionally, to study the sensitivity between physical mechanisms associated with cold episodes and temperature, cold episodes are classified in three groups: Weak cold episodes (7.5 ≤ Tmin ≤ 10 percentile), strong cold episodes (Tmin ≤ 2.5 percentile), but excluding the 9 coldest events (Tmin ≤ 0 ͦ C), henceforth referred to as extraordinary cold episodes. Several gridded reanalysis were used to characterize the large-scale circulation, cloud cover and rainfall over SA associated with these events. Weak and strong cold episodes in the MB are mainly associated with a weakening of the Bolivian High-Nordeste Low system by tropical-extratropical interactions. Both types of cold episodes are associated with westerly wind anomalies at mid- and upper-tropospheric levels aloft the Peruvian Central Andes, which inhibit the influx of humid air masses from the lowlands to the east and hence limit the development of cloud cover (e.g., positive OLR anomalies over MB). The resulting clear sky conditions cause nighttime temperatures to drop, leading to cold extremes below 10-percentile. Simultaneously, northeastern Brazil (NEB) registers negative OLR anomalies, strong convection and enhanced cloud cover because displacement of the South Atlantic Convergence Zone (SACZ) toward the northeast of

Unraveling the diversification history of grasshoppers belonging to the “Trimerotropis pallidipennis” (Oedipodinae: Acrididae species group: a hotspot of biodiversity in the Central Andes

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Noelia Verónica Guzmán

2017-09-01

Full Text Available The Andean Mountain range has been recognized as one of the biodiversity hotspots of the world. The proposed mechanisms for such species diversification, among others, are due to the elevation processes occurring during the Miocene and the intensive glacial action during the Pleistocene. In this study we investigated the diversification history of the grasshopper Trimerotropis pallidipennis species complex which shows a particularly wide latitudinal and altitudinal distribution range across the northern, central and southern Andes in South America. Many genetic lineages of this complex have been so far discovered, making it an excellent model to investigate the role of the central Andes Mountains together with climatic fluctuations as drivers of speciation. Phylogenetics, biogeographic and molecular clock analyses using a multi-locus dataset revealed that in Peru there are at least two, and possibly four genetic lineages. Two different stocks originated from a common ancestor from North/Central America—would have dispersed toward southern latitudes favored by the closure of the Panama Isthmus giving rise to two lineages, the coastal and mountain lineages, which still coexist in Peru (i.e., T. pallidipennis and T. andeana. Subsequent vicariant and dispersal events continued the differentiation process, giving rise to three to six genetic lineages (i.e., clades detected in this study, which were geographically restricted to locations dispersed over the central Andes Mountains in South America. Our results provide another interesting example of “island diversification” motored by the topography plus unstable climatic conditions during the Pleistocene, pointing out the presence of a hotspot of diversification in the Andean region of Peru.

Luchas y defensas escondidas. Pluralismo legal y cultural como una práctica de resistencia creativa en la gestión local del agua en los Andes

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Boelens, Rutgerd

2011-12-01

Full Text Available In the Andes, water rights are enforced in processes of social struggle. This paper explains how water struggles by Andean user collectives cannot be understood aside from their rootedness in dynamic ‘undertows’: the multi-layered, often concealed water-rights foundations. They entwine plural legal sources and livelihood strategies; there, water rights are shaped materially and discursively. Undertows also constitute the socio-territorial home bases for communities’ efforts to upscale their water rights battlegrounds into broader political-legal networks. In practice, this often happens in disguised political forms: through ‘mimicry’ shields and strategies, which also enable them to shop around in rulers’ power factory. Dynamic sub-surface creation and proliferation of water rights repertoires constitute a strong source of defense against encroachment and disciplinary policies.

En los Andes, los derechos de agua se materializan en procesos de lucha social. El artículo examina cómo la lucha por el agua de los colectivos locales no puede comprenderse sin su enraizamiento en subcorrientes dinámicas: los cimientos multicapas, a menudo ocultos, de los derechos de agua. Aquí se entrelazan estrategias comunitarias y fuentes socio-legales plurales. Las subcorrientes alimentan los socio-territorios y las culturas hidráulicas, estableciendo las bases para la defensa de los derechos locales hacia redes político-legales multi-escala. En la práctica, los arreglos y derechos propios a menudo están disfrazados por medio de escudos y estrategias de mimetismo (o imitación, que también permiten hacer uso de los medios de poder dominantes. La creación y la proliferación subsuperficiales de los repertorios sociolegales locales constituyen una importante fuente de defensa contra la usurpación de los derechos de agua y las políticas disciplinarias.

Actividad microbiológica y biomasa microbiana en suelos cafetaleros de los Andes venezolanos

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Jorge E. Paolini Gómez

2018-01-01

Full Text Available En Venezuela el café (Coffea arabica L. ocupa un área aproximada de 200 000 ha, distribuidos principalmente en las zonas montañosas de Los Andes. Tradicionalmente, el café se cultiva con pocos insumos bajo la sombra de árboles de la familia de las leguminosas y de otros arbustos. En años recientes con la adopción de cultivares de alta productividad, notable precocidad y tamaño reducido se está produciendo café a plena exposición solar con fertilización mineral y uso de pesticidas. Las propiedades microbiológicas del suelo especialmente aquellas relacionadas con el flujo de energía y el reciclaje de nutrientes responden de forma rápida y sensible a los cambios de las condiciones del suelo mucho antes que por ejemplo el carbono orgánico, y de este modo, suministran una información anticipada sobre las alteraciones de la calidad del mismo. En este estudio se comparó la actividad microbiológica (respiración basal, la biomasa microbiana y los parámetros ecofisiológicos en suelos a nivel superficial (0-5 cm de ocho fincas cafetaleras en los municipios de Mérida y Trujillo donde se encuentran tres sistemas de producción: tradicional, convencional y orgánico. Las fincas con agricultura orgánica presentaron los mayores valores de carbono orgánico total, carbono hidrosoluble, respiración basal y biomasa microbiana en comparación con las de manejo tradicional y convencional; con lo cual la producción orgánica es un sistema de manejo más sostenible por la mayor conservación de los recursos naturales y la producción más amigable y armónica con el ambiente. En el caso del manejo convencional, la adición de fertilizantes y pesticidas afecta de forma negativa el bienestar de los microorganismos y los hace más ineficientes en el uso del carbono y la energía.

A millennium of metallurgy recorded by lake sediments from Morococha, Peruvian Andes.

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Cooke, Colin A; Abbott, Mark B; Wolfe, Alexander P; Kittleson, John L

2007-05-15

To date, information concerning pre-Colonial metallurgy in South America has largely been limited to the archaeological record of artifacts. Here, we reconstruct a millennium of smelting activity in the Peruvian Andes using the lake-sediment stratigraphy of atmospherically derived metals (Pb, Zn, Cu, Ag, Sb, Bi, and Ti) and lead isotopic ratios (206Pb/ 207Pb) associated with smelting from the Morococha mining region in the central Peruvian Andes. The earliest evidence for metallurgy occurs ca. 1000 A.D., coinciding with the fall of the Wari Empire and decentralization of local populations. Smelting during this interval appears to have been aimed at copper and copper alloys, because of large increases in Zn and Cu relative to Pb. A subsequent switch to silver metallurgy under Inca control (ca. 1450 to conquest, 1533 A.D.) is indicated by increases in Pb, Sb, and Bi, a conclusion supported by further increases of these metals during Colonial mining, which targeted silver extraction. Rapid development of the central Andes during the 20th century raised metal burdens by an order of magnitude above previous levels. Our results represent the first evidence for pre-Colonial smelting in the central Peruvian Andes, and corroborate the sensitivity of lake sediments to pre-Colonial metallurgical activity suggested by earlier findings from Bolivia.

INVENTARIO DE MAMÍFEROS EN UN BOSQUE DE LOS ANDES CENTRALES DE COLOMBIA

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SÁNCHEZ FRANCISCO

2004-06-01

Full Text Available Se usaron técnicas de captura, observación directa y registro indirecto para obtenerun inventario de mamíferos en un bosque andino de Colombia. Se realizaronmuestreos entre octubre de 1998 y abril de 1999 en la Reserva Río Blanco (Manizales,Departamento de Caldas, entre 2200 - 3750 m de altitud. Para capturar pequeñosmamíferos no voladores se usaron trampas Sherman. Para capturar murciélagos seusaron mallas de niebla y colectas manuales. Para registrar medianos y grandesmamíferos se usaron trampas Tomahawk, puntos de observación, recorridos, trampasde huellas, rastros y encuestas. Se registraron 42 especies de mamíferospertenecientes a doce órdenes. El inventario de pequeños mamíferos no voladoresy murciélagos es incompleto; se dan sugerencias para complementarlo. Las trampasde huellas, los rastros y las encuestas fueron técnicas más eficientes para registrarmedianos y grandes mamíferos, que la captura con trampas Tomahawk, los recorridosy los puntos de observación. Se hacen observaciones y se dan recomendacionespara implementar las diferentes técnicas en bosques andinos.

Secuencias y consecuencias de algunos procesos de neolitización en los Andes

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Lavallée,Daniéle

2006-01-01

Se describen los principales procesos constitutivos de la "neolitización" andina. El Area Central Andina constituye la primera de Sudamérica donde se ha observado una sedentarización de los grupos humanos previamente a la adopción (o invención) de la agricultura. Desde el 6000 AP existen instalaciones permanentes en el litoral de Perú, orientadas a una explotación óptima de los recursos marinos. En cambio, los más antiguos indicios de especies vegetales manipuladas provienen de cuencas intera...

Aves y endemismo en los bosques relictos de la vertiente occidental andina del norte del Perú y sur del Ecuador

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Jeremy N. M. Flanagan

2013-05-01

Full Text Available Los bosques relictos de las vertientes occidentales de los Andes del norte del Perú y el sur del Ecuador forman parte de dos regiones, una la denominada región de endemismo tumbesina (caracterizada principalmente por bosques secos y otra, en altitudes mayores, la región de endemismo del sur de los Andes centrales (caracterizada por bosques nublados y páramo. La región tumbesina es reconocida por albergar gran cantidad de aves endémicas, muchas de las cuales están amenazadas, y también por el alto grado de deforestación y fragmentación de sus hábitats naturales. Este artículo presenta un resumen del estado de conservación de dichas aves y bosques, con recomendaciones para mejorar la conservación de los últimos bosques de la vertiente occidental.

Orquídeas en los alrededores de Bogotá

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Schneider Martín

1955-04-01

Full Text Available La ciudad de Bogotá, Capital de la República de Colombia, está situada en una fértil altiplanicie de la Cordillera Oriental de los Andes. El clima de esta región lo determinan principalmente dos factores: su situación en los trópicos y su altura en los Andes. EI medio tropical es la causa de una gran constancia de la temperatura, mientras que la situación elevada en los Andes reduce considerablemente la temperatura que debiéramos esperar dada la cercanía del Ecuador. Bogotá y sus alrededores forman parte de la llamada "tierra fría" colombiana, que corresponde a la zona tropical moderada.  Esta zona comprende las alturas entre los 2000 y 3500 metros sobre el nivel del mar, donde las temperaturas medias anuales fluctúan entre 17 y 8 centígrados.

(Plio-)Pleistocene alluvial-lacustrine basin infill evolution in a strike-slip active zone (Northern Andes, Western-Central Cordilleras, Colombia)

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SUTER, F.; NEUWERTH, R.; GORIN, G.; GUZMÁN, C.

2009-01-01

The (Plio)-Pleistocene Zarzal Formation was deposited in the Cauca Depression and Quindío-Risaralda Basin between the Western and Central Cordilleras (Northern Andes). This area is structurally located on the transcurrent Romeral Fault System (RFS). Because of the interaction between the Nazca plate and the Chocó-Panamá block (an active indenter), the RFS strike-slip component changes direction around the study zone (dextral in the south, senestral in the north). Zarzal sediments are the olde...

Reconstrucción espacial y temporal de la ocurrencia de avalanchas de nieve en los Andes patagónicos utilizando técnicas dendrocronológicas Dendrochronological reconstruction of spatial and temporal patterns of snow avalanches in the Patagonian Andes

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ALEJANDRO CASTELLER

2009-06-01

Full Text Available Las avalanchas de nieve representan un importante riesgo natural en diversas regiones montañosas alrededor del mundo. Daños a infraestructura y pérdidas de vidas humanas son reportados frecuentemente en relación a eventos catastróficos de avalanchas. En los Andes, numerosas obras de infraestructura se ubican en zonas vecinas a senderos de avalanchas, de las que poco se conoce sobre sus alcances máximos, periodos de retorno y presiones de impacto. A través de la implementación de técnicas dendrocronológicas hemos reconstruido las fechas de ocurrencia y áreas de influencia de eventos pasados de avalanchas de nieve. Ejemplares de Nothofagus pumilio con perturbaciones visibles de avalanchas fueron muestreados en sectores del canal, bordes y zonas de frenado de 11 senderos de avalanchas ubicados en Loma de las Pizarras, próximo a El Chaltén, Santa Cruz, Argentina. Además, áreas de control fueron muestreadas para determinar las condiciones de crecimiento en árboles no afectados por avalanchas. Nuestros análisis indican que las cicatrices, las variaciones de excentricidad en el leño, los cambios abruptos de crecimiento y la presencia de leño de tensión son los principales indicadores dendrocronológicos en N. pumilio asociados a la ocurrencia de avalanchas. Basados en una ponderación cuantitativa de los indicadores y en la profundidad de muestreo, calculamos un índice de ocurrencia de eventos, el cual nos permitió determinar para cada sendero los años con ocurrencia de avalanchas. Considerando de manera integral la actividad de avalanchas en los 11 senderos muestreados, los años con mayor ocurrencia de eventos fueron 1936, 1966, 1978 y 1995. Complementariamente, registros climáticos fueron analizados con el objetivo de determinar las relaciones entre los años con ocurrencia de avalanchas y las variaciones mensuales de precipitación y temperatura. Se observa que los años con gran frecuencia de avalanchas est

PABLO PALACIO: LA VIOLENCIA CORPORAL SOBRE LAS IDENTIDADES IMPOSIBLES EN LA ZONA DE LOS ANDES

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Diego Falconí Travez

2014-10-01

Full Text Available Pablo Palacio, escritor ecuatoriano de la segunda década del siglo pasado, se encargó de construir en sus relatos un catálogo de cuerpos raros con sexualidades ambiguas e inquietantes que se alejan del canon andino al que él pertenece. No obstante, una de las cuestiones que más llama la atención es que varios de esos cuerpos son disciplinados por ciertos discursos de poder de un modo violento. Este trabajo explora desde la teoría literaria dichas vejaciones tomando en consideración la violencia sobre las identidades de mujeres y homosexuales en dos de sus relatos, e indaga sobre cuestiones como la economía de la representación, la  violencia, su relación con el texto literario y la vulnerabilidad, como requisito sine qua non de las vejaciones, en ciertos cuerpos en la zona de los Andes.

Rock Glacier Response to Climate Change in the Argentinian Andes

Science.gov (United States)

Drewes, J.; Korup, O.; Moreiras, S.

2017-12-01

Rock glaciers are bodies of frozen debris and ice that move under the influence of gravity in permafrost areas. Rock glaciers may store a large amount of sediments and play an important role as prime movers of debris in the Andean sediment cascade. However, little is known about how much sediment and water rock glaciers may store at the mountain-belt scale, and the few existing estimates vary considerably. We address this question for the Argentinian Andes, for which a new glacial inventory containing more than 6500 rock glaciers gives us the opportunity to analyse their relevance within the sediment cascade. We examine the inventory for catchments in five sub-regions, i.e. the Desert Andes (22°-31°S); the Central Andes (31°-36°S); the Northern Andes of Patagonia (36°-45°S); the Southern Andes of Patagonia (45°-52°S); and Tierra del Fuego (52°-55°S), together with climate variables of the WorldClim datasets, and digital topographic data, to estimate how rock-glacier extents may change under different past and future climate scenarios. We observe for the northern Desert Andes that rock glacier toes are at 4000 to 5000 m a.s.l. and a mean annual temperature range of 3° and 8°C, though most rock glaciers are in areas with mean annual temperatures between -5 and 5°C, marking a distinct thermal niche. Rock glaciers are traditionally viewed as diagnostic of sporadic alpine permafrost and their toes are often near the annual mean 0°C isotherm. However, we find that only rock glaciers in the southern Desert Andes and Central Andes are located where annual mean temperature is -2°C. Future scenarios project an increase of > four degrees in these areas, which may further degrade ground ice and potentially change the rates at which rock glaciers advance. Where active rock glaciers become inactive their coarse material, which was formerly bound by ice, may be released into the sediment cascade, whereas accelerating or rapidly downwasting rock glaciers may either

El represamiento y aluvión del río Santa Cruz, Andes Principales (31°40'S), provincia de San Juan

OpenAIRE

Patricio E. D'odorico; Daniel J. Pérez; Nicolás Sequeira; Luis Fauqué

2009-01-01

En la región de los Andes Principales sanjuaninos, existe una alta concentración de deslizamientos, cuyos depósitos han originado represamientos naturales. El colapso de estos diques generados por movimientos de ladera es el proceso evolutivo más probable de estas geoformas. El análisis de imágenes satelitales y fotos aéreas permite reconstruir las características y el origen de los deslizamientos que formaron esos diques naturales. En esta región de los Andes Principales, el rápido levantami...

Low-pressure evolution of arc magmas in thickened crust: The San Pedro-Linzor volcanic chain, Central Andes, Northern Chile

Science.gov (United States)

Godoy, Benigno; Wörner, Gerhard; Kojima, Shoji; Aguilera, Felipe; Simon, Klaus; Hartmann, Gerald

2014-07-01

Magmatism at Andean Central Volcanic Zone (CVZ), or Central Andes, is strongly influenced by differentiation and assimilation at high pressures that occurred at lower levels of the thick continental crust. This is typically shown by high light to heavy rare earth element ratios (LREE/HREE) of the erupted lavas at this volcanic zone. Increase of these ratios with time is interpreted as a change to magma evolution in the presence of garnet during evolution of Central Andes. Such geochemical signals could be introduced into the magmas be high-pressure fractionation with garnet on the liquidus and/or assimilation from crustal rocks with a garnet-bearing residue. However, lavas erupted at San Pedro-Linzor volcanic chain show no evidence of garnet fractionation in their trace element patterns. This volcanic chain is located in the active volcanic arc, between 22°00‧S and 22°30‧S, over a continental crust ˜70 km thick. Sampled lavas show Sr/Y and Sm/Yb ratios Chile. We relate our geochemical observations to shallow crustal evolution of primitive magmas involving a high degree of assimilation of upper continental crust. We emphasize that low pressure AFC- (Assimilation Fractional Crystallization) type evolution of the San Pedro-Linzor volcanic chain reflects storage, fractionation, and contamination of mantle-derived magmas at the upper felsic crust (<40 km depth). The ascent of mantle-derived magmas to mid-crustal levels is related with the extensional regime that has existed in this zone of arc-front offset since Late-Miocene age, and the relatively thin portion of mafic lower crust observed below the volcanic chain.

Andes: An intelligent homework helper

Science.gov (United States)

van de Sande, Brett; Vanlehn, Kurt; Treacy, Don; Shelby, Bob; Wintersgill, Mary

2007-03-01

Andes (www.andes.pitt.edu) is an intelligent tutor homework system designed for use as the homework portion of an introductory physics course. It encourages students to use good problem solving techniques and provides immediate feedback on each step of a problem solution along with hints on request. I will discuss how Andes works, from a student perspective, and present research demonstrating its effectiveness as a pedagogical tool. Then, I will discuss using Andes as a tool for conducting education research, briefly reviewing several studies conducted using Andes. Finally, I will show how logs of student solutions to Andes problems can be used to develop cognitive models of student learning.

Contribution to the Geology of the Central and Western Cordillera of Colombia in the sector between Ibagué and Cali

NARCIS (Netherlands)

Nelson, H.W.

1957-01-01

Het Westelijk gedeelte van de Republiek Columbia (Zuid Amerika) wordt ingenomen door de Cordilleras de los Andes, welke in genoemde republiek uit drie hoofdketens bestaat, t. w. de West Cordillera, de Centrale Cordillera en de Oost Cordillera. Een studie werd gemaakt van een centraal gelegen Strook

Structural control on arc volcanism: The Caviahue Copahue complex, Central to Patagonian Andes transition (38°S)

Science.gov (United States)

Melnick, Daniel; Folguera, Andrés; Ramos, Victor A.

2006-11-01

This paper describes the volcanostratigraphy, structure, and tectonic implications of an arc volcanic complex in an oblique subduction setting: the Caviahue caldera Copahue volcano (CAC) of the Andean margin. The CAC is located in a first-order morphotectonic transitional zone, between the low and narrow Patagonian and the high and broad Central Andes. The evolution of the CAC started at approximately 4-3 Ma with the opening of the 20 × 15 km Caviahue pull-apart caldera; Las Mellizas volcano formed inside the caldera and collapsed at approximately 2.6 Ma; and the Copahue volcano evolved in three stages: (1) 1.2-0.7 Ma formed the approximately 1 km thick andesitic edifice, (2) 0.7-0.01 Ma erupted andesitic-dacitic subglacial pillow lavas, and (3) 0.01-0 Ma erupted basaltic-andesites and pyroclastic flows from fissures, aligned cones, and summit craters. Magma ascent has occurred along planes perpendicular to the least principal horizontal stress, whereas hydrothermal activity and hot springs also occur along parallel planes. At a regional scale, Quaternary volcanism concentrates along the NE-trending, 90 km long Callaqui-Copahue-Mandolegüe lineament, the longest of the southern volcanic zone, which is here interpreted as an inherited crustal-scale transfer zone from a Miocene rift basin. At a local scale within the CAC, effusions are controlled by local structures that formed at the intersection of regional fault systems. The Central to Patagonian Andes transition occurs at the Callaqui-Copahue-Mandolegüe lineament, which decouples active deformation from the intra-arc strike-slip Liquiñe-Ofqui fault zone to the south and the backarc Copahue-Antiñir thrust system.

Antecedentes geobotánicos de una cuenca andina de Chile Central

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Quintanilla Pérez, V.

2004-12-01

Hautes Andes; près de la ville de Santiago du Chili. [es] Como todos los ecosistemas de montaña; los Andes de Chile presentan una especificidad fitoecológica importante; que se expresa por la acción de condiciones ecológicas muy particulares y por la presencia de comunidades vegetales que se individualizan por sus caracteres estructurales y funcionales. Estos caracteres son el resultado de una adecuación entre las características biológicas de las plantas sometidas a los efectos de la altitud (largo periodo frío; pero que también se benefician de ciertas reservas de agua a pesar del rigor de las condiciones climáticas. Se establece una zonación altitudinal de la vegetación; determinándose tres pisos vegetales; montano; subandino y andino; resaltándose la similitud florística de las comunidades vegetales del piso montano inferior con las de los valles centrales del país. También se aportan datos sobre los procesos geomorfológicos de montaña; que afectan a la vida y a la distribución de las plantas de estos ambientes. Se presenta un estudio de un caso concreto en la Cordillera Andina; cerca de Santiago de Chile.

The role of climate in the accumulation of lithium-rich brine in the Central Andes

International Nuclear Information System (INIS)

Godfrey, L.V.; Chan, L.-H.; Alonso, R.N.; Lowenstein, T.K.; McDonough, W.F.; Houston, J.; Li, J.; Bobst, A.; Jordan, T.E.

2013-01-01

Highlights: • δ 7 Li of waters and rocks in the Central Andes were measured. • Halite/brine partition coefficients of lithium and δ 7 Li of halite were determined. • Li-rich brines have a high component of fluids of geothermal origin. • Removal of lithium by clays is minor relative to other regions of the world. • The weathering flux of lithium and sodium decouple according to climate state. - Abstract: Lithium-rich brine within the sub-surface of the Salar del Hombre Muerto (SHM) salt pan in the Andes of northwestern Argentina has a chemical and isotopic composition which is consistent with Li derived from several sources: the modern halite saturated lagoon, Li-rich salts and brines formed recently, and dissolution of halite which precipitated from ancient saline lakes. SHM lies in the closed basin that includes part of the massive Cerro Galán caldera which is drained by the Río los Patos, which is responsible for 90% of surface runoff into the salar. The low Li isotope composition, +3.4‰, of this river is consistent with significant contributions of geothermal spring water. As water drains through the volcaniclastic deposits which cover a large proportion of the basin, Li removal, as indicated by decreasing Li/Na, occurs but without significant isotope fractionation. This indicates a mechanism of surface sorption onto smectite or ferrihydrite rather than Li incorporation into octahedral structural sites of clays. These observations suggest that conditions in this high altitude desert have limited the dilution of hydrothermal spring water as well as the formation of clay minerals, which jointly have allowed the Li resource to accumulate rapidly. Changes in climate on a multi-millennial time scale, specifically in the hydrologic budget, have resulted in solute accumulation rates that have been variable through time, and decoupled Li and Na fluxes. Inflow to the salar under modern conditions has high Li/Na (7.9 × 10 −3 by wt) with δ 7 Li

Determinantes del acceso a los productos financieros en los hogares colombianos

OpenAIRE

Santiago Rodríguez-Raga; Félix Francisco Riaño Rodríguez

2016-01-01

Existe evidencia que establece una asociación positiva entre el acceso a productos financieros, la riqueza y calidad de vida de los hogares, en especial de los hogares pobres. En este ámbito, este estudio busca entender los determinantes del acceso a los diferentes productos financieros en los hogares de Colombia, utilizando un modelo econométrico con base en la información contenida en la Encuesta Longitudinal Colombiana (ELCA) de la Universidad de los Andes. Como conclusión se encuentra que...

Non-volant mammals in a protected area on the Central Andes of Colombia: new records for the Caldas department and the Chinchiná River basin

OpenAIRE

Ramírez-Mejía, Andrés; Sánchez, Francisco

2015-01-01

The Chinchiná River basin is located on the western slope of the Colombian Central Andes. This basin provides ecosystem services such as water provision for >500,000 people, but has suffered considerable ecosystem degradation, and the information on its biodiversity is limited. We inventoried the non-volant mammals in the Caldas' Central Hydroelectric (CHEC) Reserve in the Chinchiná River basin, in the Caldas department. We detected 18 species of mammals, present the first record of Puma ya...

The Influence of the Madden-Julian Oscillation (mjo) on Extreme Rainfall Over the Central and Southern Peruvian Andes

Science.gov (United States)

Heidinger, H.; Jones, C.; Carvalho, L. V.

2015-12-01

Extreme rainfall is important for the Andean region because of the large contribution of these events to the seasonal totals and consequent impacts on water resources for agriculture, water consumption, industry and hydropower generation, as well as the occurrence of floods and landslides. Over Central and Southern Peruvian Andes (CSPA), rainfall exceeding the 90th percentile contributed between 44 to 100% to the total Nov-Mar 1979-2010 rainfall. Additionally, precipitation from a large majority of stations in the CSPA exhibits statistically significant spectral peaks on intraseasonal time-scales (20 to 70 days). The Madden-Julian Oscillation (MJO) is the most important intraseasonal mode of atmospheric circulation and moist convection in the tropics and the occurrence of extreme weather events worldwide. Mechanisms explaining the relationships between the MJO and precipitation in the Peruvian Andes have not been properly described yet. The present study examines the relationships between the activity and phases of the MJO and the occurrence of extreme rainfall over the CSPA. We found that the frequency of extreme rainfall events increase in the CSPA when the MJO is active. MJO phases 5, 6 and 7 contribute to the overall occurrence of extreme rainfall events over the CSPA. However, how the MJO phases modulate extreme rainfall depends on the location of the stations. For instance, extreme precipitation (above the 90th percentile) in stations in the Amazon basin are slightly more sensitive to phases 2, 3 and 4; the frequency of extremes in stations in the Pacific basin increases in phases 5, 6 and 7 whereas phase 2, 3 and 7 modulates extreme precipitation in stations in the Titicaca basin. Greater variability among stations is observed when using the 95th and 99th percentiles to identify extremes. Among the main mechanisms that explain the increase in extreme rainfall events in the Peruvian Andes is the intensification of the easterly moisture flux anomalies, which

Importance of water quality on plant abundance and diversity in high-alpine meadows of the Yerba Loca Natural Sanctuary at the Andes of north-central Chile Importancia de la calidad del agua sobre la abundancia y diversidad vegetal en vegas altoandinas del Santuario Natural Yerba Loca en los Andes de Chile centro-norte

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ROSANNA GINOCCHIO

2008-12-01

Full Text Available Porphyry Cu-Mo deposits have influenced surface water quality in high-Andes of north-central Chile since the Miocene. Water anomalies may reduce species abundance and diversity in alpine meadows as acidic and metal-rich waters are highly toxic to plants The study assessed the importance of surface water quality on plant abundance and diversity in high-alpine meadows at the Yerba Loca Natural Santuary (YLNS, central Chile (33°15' S, 70°18' W. Hydrochemical and plant prospecting were carried out on Piedra Carvajal, Chorrillos del Plomo and La Lata meadows the growing seasons of 2006 and 2007. Direct gradient analysis was performed through canonical correspondence analysis (CCA to look for relationships among water chemistry and plant factors. High variability in water chemistry was found inside and among meadows, particularly for pH, sulphate, electric conductivity, hardness, and total dissolved Cu, Zn, Cd, Pb and Fe. Data on species abundance and water chemical factors suggests that pH and total dissolved Cu are very important factor determining changes in plant abundance and diversity in study meadows. For instance, Festuca purpurascens, Colobanthus quitensis, and Arenaria rivularis are abundant in habitals with Cu-rich waters while Festuca magellanica, Patosia clandestina, Plantago barbata, Werneria pygmea, and Erigeron andícola are abundant in habitals with dilute waters.Los megadepósitos de pórfidos de Cu-Mo han influido sobre la calidad de las aguas superficiales en las zonas altoandinas del centro-norte de Chile desde el Mioceno. Estas alteraciones en la calidad de las aguas podrían afectar negativamente a la vegetación presente en las vegas altoandinas, ya que las aguas acidas y ricas en metales son altamente tóxicas para las plantas. En este estudio se evaluó el efecto de la calidad de las aguas en la abundancia y diversidad florística de las vegas altoandinas del Santuario de la Naturaleza Yerba Loca (SNYL, en Chile central (33

Barren Miocene granitoids in the Central Andean metallogenic belt, Chile: Geochemistry and Nd-Hf and U-Pb isotope systematics Granitoides estériles del Mioceno en la franja metalogénica de los Andes Centrales, Chile: geoquímica e isotopía de Nd-Hf y U-Pb

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Katja Deckart

2010-01-01

Full Text Available Four Middle-to-Late Miocene barren plutonic complexes that occur between the giant porphyry copper deposits of the central Chilean Andes were selected for U-Pb LA-ICPMS geochronology and Hf-isotope systematics on single zircon grains. Major and trace elements and Sr-Nd-Hf isotope whole rock geochemical studies were under-taken to compare with slightly younger or coeval barren and fertile intrusive rocks between 32° and 34°S. The studied granitoids yield resolvable crystallization ages of 11.3±0.1 Ma (Cerro Mesón Alto massif, 10.3±0.2 Ma (La Gloria pluton, 14.9±0.2 Ma/14.9±0.1 Ma (Yerba Loca stock and 11.2±0.1 Ma/14.7±0.1 Ma (San Francisco Batholith. Major and trace elements discard an adakitic signature as suggested for coeval porphyric intrusions at 32°S, slightly younger mineralized porphyries at Río Blanco-Los Bronces deposit and other Cenozoic adakites. Volcanic host rocks are less fractionated than the intrusive rock units. The same observation can be made for the unmineralized northern plutons compared to the southern ones. Initial Sr-Nd isotope data show insignificant variation (0.703761-0.704118 and 0.512758-0.512882, plotting in the mantle array. Trace element enrichment can be explained by addition of subducted-slab fluids and/or terrigenous sediments to the mantle wedge prior to and/or slight crustal input during magma ascent. Zircon grains separated from these barren intrusives share a similar initial εHf i-data variation for the younger age group (10-12 Ma; 7.04-9.54 and show a more scattered range for the older one (14-15 Ma; 8.50-15.34; both sets plot between the DM and CLTUR evolution lines. There is evidence that magma evolution was slightly distinct through time from older to younger barren magmatism, compared to a few fertile porphyritic rocks from Río Blanco-Los Bronces porphyry copper deposit. It is suggested that chronological inconsistencies within these complexes might be related to differential shortening

Relationships between mineralization and silicic volcanism in the central Andes

Energy Technology Data Exchange (ETDEWEB)

Francis, P.W.; Halls, C.; Baker, M.C.W.

1983-10-01

Studies of late Tertiary silicic volcanic centers in the Western and Eastern Cordilleras of the Central Andes show that three volcanic environments are appropriate sites for mineralization: (1) ring-fracture extrusions post-dating large calderas; (2) similar extrusions within ignimbrite shields; and (3) isolated, small silicic volcanoes. Subvolcanic tin mineralization in the Eastern Cordillera is located in silicic stocks and associated breccias of Miocene age. The Cerro Rico stock, Potosi, Bolivia, contains tin and silver mineralization and has an intrusion age apparently millions of years younger than that of the associated Kari Kari caldera. Similar age relationships between mineralization and caldera formation have been described from the San Juan province, Colorado. The vein deposits of Chocaya, southern Bolivia, were emplaced in the lower part of an ignimbrite shield, a type of volcanic edifice as yet unrecognized in comparable areas of silicic volcanism. The El Salvador porphyry copper deposit, Chile, is related to silicic stocks which may have been intruded along a caldera ring fracture. Existing models for the genesis of porphyry copper deposits suggest that they formed in granodioritic stocks located in the infrastructure of andesitic stratovolcanoes. The dome of La Soufriere, Guadeloupe is proposed as a modern analog for the surface expression of subvolcanic mineralization processes, the phreatic eruptions there suggesting the formation of hydrothermal breccia bodies in depth.

Resignificación de la muerte en los Andes: La festividad de Wiñay Pacha o todas las almas en Santiago de Chile

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Francisca Fernández Droguett

2014-12-01

Full Text Available Desde el 2009 diversas organizaciones y agrupaciones de danza y música andina, han comenzado a conmemorar el día de difuntos en la ciudad de Santiago, denominándola Wiñay Pacha o Todas Almas. El siguiente artículo tiene por objetivo caracterizar esta práctica festiva desde los elementos culturales que configuran la visión de la muerte de los pueblos indígenas de Los Andes, a través de la vivencia del duelo y la forma de conmemorar a los difuntos, para luego reflexionar el modo en que se ha ido resignificando en el contexto urbano, mediante la revisión de su origen como festividad y su expresión como reivindicación de otros modos de vivenciar la muerte. La investigación se aborda desde una aproximación etnográfica, utilizando para la recopilación de datos la revisión bibliográfica, observación participante y entrevistas en profundidad.

A glassy lava flow from Toconce volcano and its relation with the Altiplano-Puna Magma Body in Central Andes

Science.gov (United States)

Godoy, B.; Rodriguez, I.; Aguilera, F.

2012-12-01

Toconce is a composite stratovolcano located at the San Pedro - Linzor volcanic chain (SPLVC). This volcanic chain distributes within the Altiplano-Puna region (Central Andes) which is characterized by extensive rhyodacitic-to-rhyolitic ignimbritic fields, and voluminous domes of dacitic-to-rhyolitic composition (de Silva, 1989). The felsic melts that gave origin to ignimbrites and domes at this area were generated by mixing of mantle-derived magmas and anatectic melts assimilated during their ascent through the thick crust. Thus, partially molten layers exist in the upper crust below the APVC (de Silva et al., 2006). Evidence of large volumes of such melts has been also proposed by geophysical methods (i.e. the Altiplano-Puna Magma Body; Chmielowsky et al., 1999) In this work, petrography and whole rock, mineralogical and melt inclusions geochemistry of a glassy lava flow of Toconce volcano are presented. Petrographically, this lava flow shows a porphyric texture, with euhdral to subhedral plagioclase, ortho- and clino-pyroxene phenocrysts immersed in a glassy groundmass. Geochemically, the lava flow has 64.7% wt. SiO2. The glassy groundmass (~70% wt. SiO2) is more felsic than all the lavas in the volcanic chain (47-68% wt., Godoy et al., 2011). Analyzed orthopyroxene-hosted melt inclusions show an even higher SiO2 content (72-75% wt.), and a decreasing on Al2O3, Na2O, and CaO content with differentiation. Crystallization pressures of this lava flow, obtained using Putirka's two-pyroxene and clinopyroxene-liquid models (Putirka, 2008), range between 6 and 9 kbar. According to crystallization pressures, and major element composition, a felsic source located at shallow crustal pressures - where plagioclase is a stable mineralogical phase - originated the inclusions. This could be related to the presence of the Altiplano-Puna Magma Body (APMB) located below SPLVC. On the other hand, glassy groundmass, and disequilibrium textures in minerals of this lava flow could

The Mass Elevation Effect of the Central Andes and Its Implications for the Southern Hemisphere's Highest Treeline

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Wenhui He

2016-05-01

Full Text Available One of the highest treelines in the world is at 4810 m above sea level on the Sajama Volcano in the central Andes. The climatological cause of that exceptionally high treeline position is still unclear. Although it has been suggested that the mass elevation effect (MEE explains the upward shift of treelines in the Altiplano region, the magnitude of MEE has not yet been quantified for that region. This paper defines MEE as the air temperature difference in summer at the same elevation between the inner mountains/plateaus (Altiplano and the free atmosphere above the adjacent lowlands of the Andean Cordillera. The Altiplano air temperature was obtained from the Global Historical Climatology Network-Monthly temperature database, and the air temperature above the adjacent lowlands was interpolated based on the National Center for Environmental Prediction/National Center for Atmospheric Research Reanalysis 1 data set. We analyzed the mean air temperature differences for January, July, and the warm months from October to April. The air temperature was mostly higher on the Altiplano than over the neighboring lowlands at the same altitude. The air temperature difference increased from the outer Andean east-facing slope to the interior of the Altiplano in summer, and it increased from high latitudes to low latitudes in winter. The mean air temperature in the Altiplano in summer is approximately 5 K higher than it is above the adjacent lowlands at the same mean elevation, averaging about 3700 m above sea level. This upward shift of isotherms in the inner part of the Cordillera enables the treeline to climb to 4810 m, with shrub-size trees reaching even higher. Therefore, the MEE explains the occurrence of one of the world’s highest treelines in the central Andes.

Circulation, échange et production de poteries dans les Andes Centrales au deuxième millénaire AV. J.C

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1990-01-01

Full Text Available Sont présentés tout d’abord les quatre types céramiques définis pour la séquence Pirwa de Piruru (1600/1500 - 800/600 av. J.C.. Puis, après quelques réflexions méthodologiques à propos de la détermination de groupes céramiques pertinents, particulièrement durant le Formatif Initial, Piruru Pirwa est replacé dans le contexte culturel de la cordillère centre-andine, des changements significatifs étant constatés entre les phases Pirwa II et III. Les analyses céramologiques montrent que trois types sont importés et que le quatrième résulte d’une production locale. Les variations dans l’organisation globale de l’habitat Pirwa II et Pirwa III permettent de proposer l’hypothèse que l’activité céramique, c’est-à-dire la production de vaisselles, pourrait, dans l’exemple de Piruru, dépendre de la sédentarité. Circulación, intercambio y producción de cerámica en los Andes Centrales durante el segundo milenio a. C. En primer lugar, se presentan los cuatro tipos cerámicos definidos para la secuencia Pirwa de Piruru (1600/1500 - 800/600 a.C.. Luego, después de unas reflexiones metodológicas acerca de la determinación de grupos cerámicos pertinentes, especialmente durante el período Formativo Inicial, se sitúa Piruru Pirwa en el contexto cultural de la sierra central, notando cambios significativos entre las fases Pirwa II y Pirwa III. Los análisis ceramológicos muestran que tres tipos son importados, y que el cuarto es resultado de una producción local. Tomando en cuenta las variaciones en la organización general del asentamiento Pirwa II y Pirwa III, se plantea la hipótesis que la actividad cerámica, es decir la producción alfarera, en Piruru, podría vincularse al sedentarismo. Circulation, exchange and production of wares in the Central Highlands of Peru during the secund millenium B.C. In this paper, four ceramic types are defined and described for the Piruru Pirwa sequence (1600/1500 - 800/600 a C, and

De la complementariedad a la voluntad de Aplanar los Andes: representaciones de la naturaleza y pensamiento económico y político en el Perú del siglo XX

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2001-01-01

Full Text Available DE LA COMPLÉMENTARITÉ À LA VOLONTÉ D’APLANIR LES ANDES : REPRÉSENTATIONS DE LA NATURE ET PENSÉE ÉCONOMIQUE ET POLITIQUE AU PÉROU AU COURS DU XXÈME SIÈCLE. La représentation la plus courante du territoire péruvien à l’échelle nationale est celle qui le divise en trois régions dites “naturelles”, la costa, la sierra et la selva. Mais cette division et chacun de ses éléments peuvent prendre différents sens et ont orienté la réflexion politique tantôt vers l’idée d’une complémentarité entre ces trois ensembles et entre les “étages écologiques” qui les composent, tantôt vers celle d’une opposition insurmontable entre les Andes et leur piémont côtier - le piémont amazonien n’étant que plus rarement au centre des débats -. Cette seconde “traduction” de la nature semble aujourd’hui la plus influente et la représentation “négative” de la montagne comme espace de pauvreté et d’isolement tend dans le contexte du néolibéralisme à l’emporter sur celle, plus positive et tout aussi construite, qui présente les Andes comme un territoire ayant permis la conservation d’une culture indigène authentique. La representación más común del territorio peruano a nivel nacional es la división en tres regiones consideradas como “naturales”, la costa, la sierra y la selva. Pero esa división y cada uno de sus elementos pueden tener diversos significados, de tal forma que guiaron la reflexión política en ocasiones hacia la idea de una complementariedad entre las tres partes y entre los pisos ecológicos que las componen, y otras veces hacia la de una oposición insalvable entre los Andes y su piedemonte costeño (mientras el amazónico suscitaba menos interés. La segunda de estas “traducciones” de la naturaleza parece ser hoy en día la más influyente: la representación “negativa” de la sierra como espacio de pobreza y de aislamiento tiende, dentro del contexto del neoliberalismo, a prevalecer sobre aqu

Síndrome de burnout – estrés laboral y su influencia en el desempeño de los docentes de la Facultad de Ingeniería de la Universidad Peruana los Andes – 2015

OpenAIRE

Cantorin Poma, Oscar Luis

2017-01-01

El presente trabajo de investigación tuvo como objetivo principal determinar la influencia existente entre el Síndrome de Burnout (estrés laboral) y el Desempeño delos docentes de la facultad de Ingeniería Civil de la Universidad Peruana los Andes. Tiene un enfoque cuantitativo, donde se utilizó el tipo de investigación descriptiva correccional-causal que tiene el propósito de describir situaciones o eventos de relaciones y causalidad entre ambas variables. Para responder a las interrogantes ...

Ethnoecology of the tropical Andes avian indicators of landscape change in highland Ecuador.

Directory of Open Access Journals (Sweden)

Sarmiento, F. O.

2005-12-01

traditionnelles associées à ces preuves ornithologiqiies nous aident à comprendre la dynamique des pat/sages culturels, avec des oiseaux comme mandataires des synergies qui affectent les complexités de la nature et de la culture. Un paradoxe de la conservation est révélé par les indicateurs aviaires. Les quatre espèces choisies sont des cas où le changement de paysage et la diversité biologique nous ont donné des aperçus des avancées ethnologiques. À la différence de la préservation offerte par des réserves naturelles absolues, l'intendance du paysage, les droits de passage de la conservation et les paysages culturels sont enumeres sur la liste de scénarios pour la conservation des forêts humides, une liste qui comprend les lieux sacrés et les endroits spirituels comme des valeurs intangibles dans les Andes tropicales méritant une protection. [es] Cuatro especies de aves andinas ofrecen pistas para replantear la etnoecología de las pluviisilvas neotropicales, desafiando la noción de conservación basada solamente en recursos hídricos y biodiversidad. Usando evidencias, tanto arqueológicas como ecológicas actuales, se argumenta que el rol de los humanos en la formación y el mantenimiento de los paisajes altoandinos es un factor importante para la conservación de los bosques tropicales montanos húmedos, en particular en las montañas ecuatoriales. El ejemplo de las aves demuestra los lazos intrínsecos que unen cultura y naturaleza en los Andes tropicales. El conocimiento tradicional asociado a las pistas ornitológicas ayuda a entender la dinámica de los paisajes culturales, usando a las aves como aproximación a las sinergias que afectan tanto a la cultura andina como a la naturaleza en toda su complejidad. Una paradoja de conservación destaca en los indicadores de avifauna. Las cuatro especies seleccionadas señalan casos en donde el cambio de paisaje y la diversidad siguen de cerca los avances etnoecológicos. A diferencia de la preservación en

Glaciation in the Andes during the Lateglacial and Holocene

Science.gov (United States)

Rodbell, Donald T.; Smith, Jacqueline A.; Mark, Bryan G.

2009-10-01

This review updates the chronology of Andean glaciation during the Lateglacial and the Holocene from the numerous articles and reviews published over the past three decades. The Andes, which include some of the world's wettest and driest mountainous regions, offer an unparalleled opportunity to elucidate spatial and temporal patterns of glaciation along a continuous 68-degree meridional transect. The geographic and altitudinal extent of modern glaciers and the sensitivity of both modern and former glaciers to respond to changes in specific climatic variables reflect broad-scale atmospheric circulation and consequent regional moisture patterns. Glaciers in the tropical Andes and in the mid-latitude Andes are likely to have been far more sensitive to changes in temperature than glaciers in the dry subtropical Andes. Broad-scale temporal and spatial patterns of glaciation during the Lateglacial are apparent. In the southernmost Andes, the Lateglacial chronology appears to have a strong Antarctic signature with the best-dated moraines correlating closely with the Antarctic Cold Reversal. The southernmost Andes do not appear to have experienced a significant ice advance coeval with the Younger Dryas (YD) climatic reversal. At the other end of the Andes, from ˜0 to 9°N, a stronger YD connection may exist, but critical stratigraphic and geochronologic work is required before a YD ice advance can be fully demonstrated. In the central Andes of Peru, well-dated moraines record a significant ice readvance at the onset of the YD, but ice was retreating during much of the remaining YD interval. The spatial-temporal pattern of Holocene glaciation exhibits tantalizing but incomplete evidence for an Early to Mid-Holocene ice advance(s) in many regions, but not in the arid subtropical Andes, where moraines deposited during or slightly prior to the Little Ice Age (LIA) record the most extensive advance of the Holocene. In many regions, there is strong evidence for Neoglacial

Glaciers et évolution climatique dans les Andes boliviennes. Glacier de Zongo et glacier de Chacaltaya Cordillère Royale, 16°S

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1995-01-01

Full Text Available SEDIMENTOLOGY OF THE HUANCANE FORMATION (NEOCOMIAN OF THE CUSCO REGION AND ITS RELATION TO SEA LEVEL VARIATIONS. The Huancane formation (Neocomian of the Cusco region is mainly composed of quartz sandstones which are deposited in fluvial environments. The facies recognized are organized in a vertical sequence: fluvial sheet sandstones, oxidized or eroded surface, the shale facies of alluvial plain and unusual limestone facies of possible marine origin. These vertical facies sequences show that eustatic sea level variations controlled the fluvial sedimentation. The rivers came from the NE and were fed by the erosion of the Brazilian Shield. The sedimentation developed above the boundary of the SW edge of the Eastern basin, and the Cusco-Puno Swell which had locale horst and grabens inherited from pre-neocomian relief. GLACIARES Y EVOLUCIÓN CLIMÁTICA EN LOS ANDES BOLIVIANOS GLACIAR DE ZONGO Y GLACIAR DE CHACALTAYA, CORDILLERA REAL, 16°S. Por su sensibilidad y su plazo de respuesta breve, el glaciar es de un gran interés para analizar la evolución y la variabilidad actuales del clima entre los trópicos. Se presentan los métodos de determinación del balance de masas y del balance hidrológico, con una frecuencia de mediciones mensual. Los resultados recogidos durante tres años (1991-1994 muestran una grande variabilidad. Ésta es controlada sobre todo por la extensión del periodo de precipitaciones en medio de la temporada cálida que dura más o menos 6 meses. Los eventos ENSO (El Niño Southern Oscillation son asociados a balances netamente negativos, lo que es demostrado por la respuesta del glaciar al episodio de 1991-1992 y por la reconstrucción de los balances efectuados en base a los datos hidrológicos durante los dos últimos decenios. El retroceso acelerado de los glaciares tropicales desde los años 1980 es vinculado a la vez a una sucesión de eventos ENSO y al recalentamiento atmosférico. GLACIERS AND CLIMATIC EVOLUTION IN

Estrés académico en estudiantes de la Facultad de Farmacia y Bioanálisis, Universidad de los Andes, Mérida-Venezuela

OpenAIRE

Labrador Chacón, Carmen Zulay

2012-01-01

En esta tesis se ha tenido como objetivo, estudiar el estrés académico, así como algunos recursos psicosociales empleados, para su afrontamiento, en estudiantes de la Universidad de Los Andes, Mérida-Venezuela. La muestra estuvo constituida por 856 estudiantes del curso regular, de la Facultad de Farmacia y Bioanálisis. Para la medición del nivel de estrés académico se empleó el Cuestionario de Evaluación del Estrés Académico (CEEA) (Joan De Pablo, 2002). Para medir las variables sociodemográ...

Uso de redes sociales en las revistas científicas de la Universidad de Los Andes, Venezuela

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Christian Alexander Martínez-Guerrero

2018-01-01

Full Text Available En una sociedad donde las barreras parecen día a día más difusas, las Redes Sociales (RRSS constituyen uno los principales vehículos de comunicación directo para acceder, compartir, usar y apropiarse de contenidos que hasta hace algún tiempo implicaba mayores labores. El objetivo de este estudio fue ofrecer un diagnóstico sobre la participación en estos canales, como medios adecuados para la divulgación de conocimientos, en cada una de las 90 revistas científicas de la Universidad de Los Andes (ULA, abordado desde una metodología de trabajo de carácter documental, con diseño no experimental-transversal de tipo descriptivo, donde se determinó la presencia -y sus respectivas características- de los objetos de estudio en dos RRSS horizontales-generalistas: Facebook y Twitter, y dos verticales, de contenido y de perfiles profesionales: Youtube y LinkedIn, dadas sus capacidades de apertura y penetración en una parte importante de la población que tiene conexión a la Red. Sin embargo, se percibió que apenas el 22,3 % de las publicaciones periódicas analizadas es miembro de al menos una de estas RRSS, algunas no cuentan con constante actividad y, por tanto, la cifra de suscriptores es corta y su alcance limitado. Se recomienda al personal que allí hace vida académica procurar esfuerzos para alcanzar mejores índices de visibilidad y difusión, así como el registro en más comunidades virtuales y el trabajo constante en el mantenimiento de ellas.

Abundancia y biomasa de macroinvertebrados edáficos en la temporada lluviosa, en tres usos de la tierra, en los Andes colombianos

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Pardo Luis C

2006-03-01

Full Text Available COMPENDIO los usos evaluados fueron pastizal, cafetal y bosque secundario (Vereda Villa del Rosario, Aprox. 3º 33' 16â€? Latitud Norte y 76º 36' 01â€? Longitud Oeste, altitud 1.500 a 1.820m., precipitación 960 a 1.050 mm/año, 19.8 a 21.2º C con la metodología TSBF. Se implementaron tres monolitos por uso y cada uno se subdividió en cuatro estratos (hojarasca, 0-10 cm, 10-20 cm, y 20-30 cm, las variables densidad y biomasa por parcela y estrato se examinaron a través de ANOVAS y Post-Anovas. En abundancia la supremacía fue de hormigas (25584 ejemplares, miriápodos (4808 ejemplares y lombrices (1984 ejemplares, la diferencia significativa la marcaron los miriápodos (F=4.84, P=0.014 asociados con bosque y cafetal con sombrío. En biomasa los grupos más importantes fueron miriápodos (701.05 g m-2, 58.71%, lombrices (90.64 g m-2; 7.59%, chisas (27.07 g m-2; 2.26% hor­migas (20.90 g m-2; 1.75% y arañas (15.71 g m-2 ; 1.31%, con diferencias significativas en hormigas (F=4.17, P=0.024 y arañas (F=3.43, P=0.4024; También hubo diferencias estadísticas significativas en la densidad y biomasa de macroinvertebrados y los estratos de los monolitos, los resultados indican que estos organismos expresan en su población y biomasa respuestas ambientales asociadas más con la estructura del agroecosistema que con la variación química, física o microbiológica del hábitat; se recomienda discriminar taxonómicamente los grupos funcionales y ampliar los muestreos a la temporada seca. Palabras clave: uso del suelo, macroinvertebrados edáficos, densidad, abundancia, agroecosistemas, Andes colombianos. ABSTRACT Abundance and biomass of soil macroinvertabrates during the rainy season in three land use systems in the Colombian Andes. Using the TSBF methodology, three land use systems—pastures, coffee plantation, and secondary forest— were evaluated in the rural community of Villa del Rosario, located in the

Determinantes del acceso a los productos financieros en los hogares colombianos

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Santiago Rodríguez-Raga

2016-01-01

Full Text Available Existe evidencia que establece una asociación positiva entre el acceso a productos financieros, la riqueza y calidad de vida de los hogares, en especial de los hogares pobres. En este ámbito, este estudio busca entender los determinantes del acceso a los diferentes productos financieros en los hogares de Colombia, utilizando un modelo econométrico con base en la información contenida en la Encuesta Longitudinal Colombiana (ELCA de la Universidad de los Andes. Como conclusión se encuentra que los principales determinantes del acceso a productos financieros son el nivel de ingreso o riqueza, la educación y la estabilidad en términos laborales.

Diversidad y dinámica de un bosque subandino de altitud en la región norte de los Andes colombianos

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Jesús Oswaldo Velásquez Restrepo

2012-06-01

Full Text Available Los bosques sub-Andinos poseen alta diversidad biológica, de los cuales poco se conoce sobre su dinámica natural. Se evaluaron patrones de diversidad y biomasa, tasas de mortalidad y reclutamiento en dos parcelas permanentes de una hectárea cada una, establecidas en bosques en altitudes entre los 2 000-2 200msnm, en la vertiente Oriental de la cordillera Occidental del norte de los Andes en Colombia. Se determino diversidad de especies mediante el índice alpha de Fisher, la dinámica del bosque se evaluó mediante tres censos durante nueve anos. En total, se hallaron 1 964 individuos con un diámetro a la altura del pecho DAP≥10cm. pertenecientes a 222 especies, 113 géneros y 60 familias. La riqueza media de especies fue de 156 especies por hectárea y un índice alpha medio de Fisher de 56.2/h. Las tasas de mortalidad y reclutamiento fueron de 0.88% y 1.16% respectivamente, lo cual no indica que se presente un efecto externo proveniente del calentamiento global sobre la dinámica del bosque. La biomasa aérea promedio fue de 243.44±9.82tn/ha con un incremento anual promedio de 2.9ton/ha, valor superior a los reportados, lo cual sugiere que el equilibrio para este bosque no se ha alcanzado. De acuerdo con las observaciones de campo, este bosque parece estar recuperándose de una alteración pasada.

Las especies nativas y la deforestación en los Andes. Una visión histórica, social y cultural en Cochabamba, Bolivia

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1993-01-01

Full Text Available LES ESPECES NATIVES ET LA DÉFORESTATION DANS LES ANDES - UNE VISION HISTORIQUE, SOCIALE ET CULTURELLE A COCHABAMBA, BOLIVIE. Ce travail présente les résultats de 3 ans d’observations de terrain, de conversations avec les paysans, complétées par une large révision bibliographique. à travers une reconstitution historique, sociale et culturelle, il essaie de montrer la dynamique régressive de la végétation andine, en particulier à Cochabamba. Les forêts résiduelles, les documents des chroniqueurs des XVIè et XVIIè siècles, des explorateurs et les travaux actuels des chercheurs sont les éléments qui permettent d’imaginer les associations végétales et les types de boisements qui existaient dans le passé. En partant d’une analyse des modes d’utilisation de l’espace par les différentes sociétés qui ont peuplé les Andes, ses vallées et ses zones hautes, depuis la préhistoire jusqu’à notre époque, cette étude procède à une interprétation des causes de la déforestation, si alarmante aujourd’hui. Ainsi, les effets de l’augmentation de la population, la pression du bétail, le rôle des mines, la construction des chemins de fer sont analysés sous l’éclairage de leur influence sur la végétation native. Les implications de la fabrication de la chicha, du foncier et des nombreuses guerres ou batailles militaires sur la dégradation de l’environnement sont aussi prises en compte. La connaissance des éléments du passé amène, en conclusion, à présenter de futures pistes de travail, techniques et sociales, pour réduire ou contrecarrer la déforestation. El presente estudio suma los frutos de 3 años de observaciones de campo y de intercambios con los campesinos a una revisión bibliográfica amplia. Intenta presentar, mediante una reconstitución histórica, social y cultural, la dinámica regresiva de la vegetación andina, en particular en Cochabamba. Las huellas de los bosques relictos, los documentos de

Resilience and adaptations of rural communities and agricultural land use in the tropical Andes: Coping with environmental and socio-economic changes

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Stadel, Ch.

2008-12-01

Full Text Available In spite of a long settlement history of the tropical Andes, rural farming communities have always been exposed to conditions of ecological and economic vulnerability, risks, and even disasters. This has resulted, at certain times and in some regions, to a destabilization of livelihoods and to a manifestation of various forms of marginalization, to poverty or outmigration. However, Andean communities , over a long time, have given admirable testimonies of resilience and adaptations in the face of adverse conditions or new challenges. This paper examines the potentials and different facets of resilience and adaptation strategies of the rural campesinado in the tropical Andes. It emphasizes the proven traditional concepts of verticality, complementarity, reciprocity, and mutual community support, which to date support the feasibility and sustainability of Andean farming and community survival. In spite of this recognition, it is argued that Andean rural livelihoods always had to adapt to new developments, to threats and challenges, as well as to opportunities and alternative potentials. In the face of an almost ubiquitous penetration of modernization, new technologies, and economic and cultural globalization, the fundamental question arises, whether this can be considered as a path to progress and development, or as a threat to the survival of small-scale farming and rural community living. The paper concludes by formulating, albeit in a tentative form, some general suggestions for ‘development’ approaches and for research priorities in the rural Andes.

A pesar de una tradición muy extensa del asentamiento humano en los Andes tropicales, las comunidades campesinas siempre enfrentaron condiciones de vulnerabilidad ecológica y económica, con varios riesgos, y aun desastres. Eso ha resultado, en diversos tiempos y en algunas regiones, en una estabilización de la superviviencia humana y en varias manifestaciones de marginalización, de

Evidence of Teleconnections between the Peruvian central Andes and Northeast Brazil during extreme rainfall events

Science.gov (United States)

Sulca, J. C.; Vuille, M. F.; Silva, F. Y.; Takahashi, K.

2013-12-01

Knowledge about changes in regional circulation and physical processes associated with extreme rainfall events in South America is limited. Here we investigate such events over the Mantaro basin (MB) located at (10°S-13°S; 73°W-76°W) in the central Peruvian Andes and Northeastern Brazil (NEB), located at (9°S-15°S; 39°W-46°W). Occasional dry and wet spells can be observed in both areas during the austral summer season. The main goal of this study is to investigate potential teleconnections between extreme rainfall events in MB and NEB during austral summer. We define wet (dry) spells as periods that last for at least 3 (5) consecutive days with rainfall above (below) the 70 (30) percentile. To identify the dates of ocurrence of these events, we used daily accumulated rainfall data from 14 climate stations located in the Mantaro basin for the period 1965 to 2002. In NEB we defined a rainfall index which is based on average daily gridded rainfall data within the region for the same period. Dry (wet spells) in the MB are associated with positive (negative) OLR anomalies which extend over much of the tropical Andes, indicating the large-scale nature of these events. At 200 hPa anomalous easterly (westerly) zonal winds aloft accompany wet (dry) spells. Composite anomalies of dry spells in MB reveal significant contemporaneous precipitation anomalies of the opposite sign over NEB, which suggest that intraseasonal precipitation variability over the two regions may be dynamically linked. Indeed upper-tropospheric circulation anomalies over the central Andes extend across South America and appear to be tied to an adjustment in the Bolivian High-Nordeste Low system. Dry (wet) spells in NEB are equally associated with a large-scale pattern of positive (negative) OLR anomalies; however, there are no related significant OLR anomalies over the MB during these events. Dry (wet) spells are associated with robust patterns of anomalous wind fields at both low and upper

Características de uso de plaguicidas químicos y riesgos para la salud en agricultores de la sierra central del Perú

OpenAIRE

Ymelda Montoro; Rocío Moreno; Luis Gomero; Maria Reyes

2009-01-01

Con el objetivo de conocer las características sobre el uso e impactos en la salud de los plaguicidas químicos de uso agrícola en las provincias de Chupaca y Concepción en los andes centrales del Perú, se desarrolló un estudio descriptivo transversal entre abril y junio del año 2005, por medio de un cuestionario aplicado a 435 agricultores. Asimismo, se exploró la ubicación de los centros de expendio y la frecuencia de ventas de productos, además, se evaluó los casos de intoxicación reportado...

Modeling Soil Organic Carbon Variation Along Climatic and Topographic Trajectories in the Central Andes

Science.gov (United States)

Gavilan, C.; Grunwald, S.; Quiroz, R.; Zhu, L.

2015-12-01

The Andes represent the largest and highest mountain range in the tropics. Geological and climatic differentiation favored landscape and soil diversity, resulting in ecosystems adapted to very different climatic patterns. Although several studies support the fact that the Andes are a vast sink of soil organic carbon (SOC) only few have quantified this variable in situ. Estimating the spatial distribution of SOC stocks in data-poor and/or poorly accessible areas, like the Andean region, is challenging due to the lack of recent soil data at high spatial resolution and the wide range of coexistent ecosystems. Thus, the sampling strategy is vital in order to ensure the whole range of environmental covariates (EC) controlling SOC dynamics is represented. This approach allows grasping the variability of the area, which leads to more efficient statistical estimates and improves the modeling process. The objectives of this study were to i) characterize and model the spatial distribution of SOC stocks in the Central Andean region using soil-landscape modeling techniques, and to ii) validate and evaluate the model for predicting SOC content in the area. For that purpose, three representative study areas were identified and a suite of variables including elevation, mean annual temperature, annual precipitation and Normalized Difference Vegetation Index (NDVI), among others, was selected as EC. A stratified random sampling (namely conditioned Latin Hypercube) was implemented and a total of 400 sampling locations were identified. At all sites, four composite topsoil samples (0-30 cm) were collected within a 2 m radius. SOC content was measured using dry combustion and SOC stocks were estimated using bulk density measurements. Regression Kriging was used to map the spatial variation of SOC stocks. The accuracy, fit and bias of SOC models was assessed using a rigorous validation assessment. This study produced the first comprehensive, geospatial SOC stock assessment in this

Kinematics, Exhumation, and Sedimentation of the North Central Andes (Bolivia): An Integrated Thermochronometer and Thermokinematic Modeling Approach

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Rak, Adam J.; McQuarrie, Nadine; Ehlers, Todd A.

2017-11-01

Quantifying mountain building processes in convergent orogens requires determination of the timing and rate of deformation in the overriding plate. In the central Andes, large discrepancies in both timing and rate of deformation prevent evaluating the shortening history in light of internal or external forcing factors. Geologic map patterns, age and location of reset thermochronometer systems, and synorogenic sediment distribution are all a function of the geometry, kinematics, and rate of deformation in a fold-thrust-belt-foreland basin (FTB-FB) system. To determine the timing and rate of deformation in the northern Bolivian Andes, we link thermokinematic modeling to a sequentially forward modeled, balanced cross section isostatically accounting for thrust loads and erosion. Displacement vectors, in 10 km increments, are assigned variable ages to create velocity fields in a thermokinematic model for predicting thermochronometer ages. We match both the pattern of predicted cooling ages with the across strike pattern of measured zircon fission track, apatite fission track, and apatite (U-Th)/He cooling ages as well as the modeled age of FB formations to published sedimentary sections. Results indicate that northern Bolivian FTB deformation started at 50 Ma and may have begun as early as 55 Ma. Acceptable rates of shortening permit either a constant rate of shortening ( 4-5 mm/yr) or varying shortening rates with faster rates (7-10 mm/yr) at 45-50 Ma and 12-8 Ma, significantly slower rates (2-4 mm/yr) from 35 to 15 Ma and indicate the northern Bolivian Subandes started deforming between 19 and 14 Ma.

Glacialmorphological reconstruction of glacier advances and glacial lake outburst floods at the Cachapoal glacier in the Dry Central Andes of Chile (34°S)

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Iturrizaga, Lasafam; Charrier, Reynaldo

2013-04-01

Throughout the Andes Mountain range of South America a general trend of glacier shrinkage has taken place in the last century. Only a few glaciers have shown a rather non-continuous trend of glacier retreat and temporally advanced or even surged during the mid-19th to 20th century. One of the earliest assumed glacier surges has occurred in the upper Cachapoal catchment area at the homonymous glacier. In climatic respect the Cachapoal glacier is located in the transition zone from the most southern part of the Dry Central Andes of Chile to the more humid zone of the Wet Andes. The region is affected mainly by winter precipitation deriving from the Westerlies. The debris-covered, 12 km-long Cachapoal glacier represents one of the largest valley glaciers in the Central Andes. It is an avalanche-fed glacier with an almost 1500 m-high head wall in its upper catchment area flowing down from Picos del Barroso (5180 m) and terminates at an elevation of 2630 m a.s.l. with a bifurcated glacier tongue. A large moraine complex, almost 2 km in length and 500 m in width, separates the two glacier lobes. During times of advanced glacier tongue positions the Ríos Molina and Cachapoal may be have blocked independently at two distinct localities which are situated about 2300 m apart from each other. A blockage with temporal lake formation has occurred at least in the years 1848, 1955 and 1981 (cf. Plagemann 1887, Peña 1981), from which the rupture of the earliest glacier barrier has been the most devastating. This event is locally reminded as "la gran avenida en seco" in the historical record. Geomorphological evidence of the past historical and modern glacier expansions is given in the proglacial area by a fresh dead-ice hummocky topography and glacial trimlines at the valley flanks. More down valley broad outwash plains and boulder clusters indicate past high energy floods produced by glacier lake outbursts. Regarding the small size of the catchment area of the Río Molina

A new species of iguanid lizard, genus Stenocercus (Squamata, Iguania), from the Central Andes in Peru.

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Venegas, Pablo J; Echevarría, Lourdes Y; García-Burneo, Karla; Koch, Claudia

2016-12-04

We describe a new species of Stenocercus from the montane forest of the right margin of the Marañón river in the northern portion of the Central Andes in northern Peru (Amazonas and La Libertad departments), at elevations ranging from 2300 to 3035 m. Stenocercus omari sp. nov. differs from other Stenocercus species, with the exception of S. amydrorhytus, S. chrysopygus, S. cupreus, S. johaberfellneri, S. latebrosus, S. melanopygus, S. modestus, S. ornatissimus, S. orientalis, and S. stigmosus, by having granular scales on the posterior surfaces of thighs, a conspicuous antehumeral fold and by lacking a vertebral crest. However, Stenocercus omari sp. nov. is easily distinguished from the aforementioned species, except S. orientalis, by the presence of prominently keeled dorsal head scales. The new species differs from S. orientalis by lacking a prominent oblique neck fold and by having a distinct deep postfemoral mite pocket.

A 60,000-year record of hydrologic variability in the Central Andes from the hydrogen isotopic composition of leaf waxes in Lake Titicaca sediments

Science.gov (United States)

Fornace, Kyrstin L.; Hughen, Konrad A.; Shanahan, Timothy M.; Fritz, Sherilyn C.; Baker, Paul A.; Sylva, Sean P.

2014-12-01

A record of the hydrogen isotopic composition of terrestrial leaf waxes (δDwax) in sediment cores from Lake Titicaca provides new insight into the precipitation history of the Central Andes and controls of South American Summer Monsoon (SASM) variability since the last glacial period. Comparison of the δDwax record with a 19-kyr δD record from the nearby Illimani ice core supports the interpretation that precipitation δD is the primary control on δDwax with a lesser but significant role for local evapotranspiration and other secondary influences on δDwax. The Titicaca δDwax record confirms overall wetter conditions in the Central Andes during the last glacial period relative to a drier Holocene. During the last deglaciation, abrupt δDwax shifts correspond to millennial-scale events observed in the high-latitude North Atlantic, with dry conditions corresponding to the Bølling-Allerød and early Holocene periods and wetter conditions during late glacial and Younger Dryas intervals. We observe a trend of increasing monsoonal precipitation from the early to the late Holocene, consistent with summer insolation forcing of the SASM, but similar hydrologic variability on precessional timescales is not apparent during the last glacial period. Overall, this study demonstrates the relative importance of high-latitude versus tropical forcing as a dominant control on glacial SASM precipitation variability.

Les flux de matières dissoutes et particulaires des Andes de Bolivie vers le rio Madeira en Amazonie brésilienne

Directory of Open Access Journals (Sweden)

1995-01-01

Full Text Available Le Rio Madeira est le principal affluent méridional de l’Amazone et le deuxième tributaire andin du bassin. L’utilisation des données obtenues en Bolivie par le PHICAB (1, et au Brésil sur le réseau du DNAEE (2, a permis de suivre l’évolution des flux de matières dissoutes et particulaires, depuis les Andes jusqu’à l’Amazone. Les flux de matières en solution [36 106 t an-1 à Villabella (3] augmentent progressivement d’amont en aval avec les débits. Les flux de matières en suspension diminuent du piedmont andin jusqu’à Villabella (258 106 t an-1 du fait d’une forte sédimentation. Ensuite, les différences notables observées au Brésil posent clairement le problème des modes d’échantillonnage et de calcul des flux sédimentaires. LOS FLUJOS DE MATERIA DISUELTA Y PARTICULAR DESDE LOS ANDES DE BOLIVIA HASTA EL RÍO MADEIRA EN EL AMAZONAS DE BRASIL. El río Madeira es el principal afluente meridional del Amazonas, y el segundo tributario andino de la cuenca. La utilización de los datos obtenidos en Bolivia por el PHICAB (1, y en el Brasil sobre la red del DNAEE (2 permite conocer la evolución de los flujos de materia disuelta y particular, desde los Andes hasta el Amazonas. Los aportes en materia disuelta [36 106 t año-1 en Villabella (3] aumentan progresivamente de aguas arriba para aguas abajo, con el caudal. Los flujos de materias en suspensión disminuyen desde el Piedemonte hasta Villabella (258 106 t año-1 por causa de una fuerte sedimentación. Después, las diferencias notables observadas en el Brasil colocan claramente el problema de los tipos de muestreo y de cálculo de los flujos de sedimentos. THE DISSOLVED AND SEDIMENT YIELDS FROM THE ANDES OF BOLIVIA TO THE MADEIRA RIVER IN THE BRAZILIAN AMAZON. The Madeira river is the main Southern tributary of the Amazon, and the second Andean tributary of the drainage basin. The use of Bolivian data from the PHICAB (1, and Brazilian data from the DNAEE (2, allow to

Nueva especie de rana (Atelopus de Los Farallones de Cali, Cordillera Occidental de Colombia

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Kattan Gustavo

1986-06-01

Full Text Available Durante la realización de colecciones herpetológicas en el Departamento del Valle del Cauca, fue encontrada una especie no descrita de Atelopus (Anura: Bufonidae en los farallones de Cali, a 2600 m de altura. Esta es la primera especie en este género que se encuentra a elevaciones superiores a 2000 m en la Cordillera Occidental. Se conocen varias especies de Atelopus en las Cordilleras Central y Oriental de Colombia y en los Andes ecuatorianos (COCHRAN y GOIN 1970; PETERS 1973; RIVERO 1963 y probablemente futuras colecciones herpetológicas continuaran revelando nuevas especies en las partes altas de la Cordillera Occidental.

Evaluation of TRMM Multi-satellite Precipitation Analysis (TMPA performance in the Central Andes region and its dependency on spatial and temporal resolution

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M. L. M. Scheel

2011-08-01

Full Text Available Climate time series are of major importance for base line studies for climate change impact and adaptation projects. However, for instance, in mountain regions and in developing countries there exist significant gaps in ground based climate records in space and time. Specifically, in the Peruvian Andes spatially and temporally coherent precipitation information is a prerequisite for ongoing climate change adaptation projects in the fields of water resources, disasters and food security. The present work aims at evaluating the ability of Tropical Rainfall Measurement Mission (TRMM Multi-satellite Precipitation Analysis (TMPA to estimate precipitation rates at daily 0.25° × 0.25° scale in the Central Andes and the dependency of the estimate performance on changing spatial and temporal resolution. Comparison of the TMPA product with gauge measurements in the regions of Cuzco, Peru and La Paz, Bolivia were carried out and analysed statistically. Large biases are identified in both investigation areas in the estimation of daily precipitation amounts. The occurrence of strong precipitation events was well assessed, but their intensities were underestimated. TMPA estimates for La Paz show high false alarm ratio.

The dependency of the TMPA estimate quality with changing resolution was analysed by comparisons of 1-, 7-, 15- and 30-day sums for Cuzco, Peru. The correlation of TMPA estimates with ground data increases strongly and almost linearly with temporal aggregation. The spatial aggregation to 0.5°, 0.75° and 1° grid box averaged precipitation and its comparison to gauge data of the same areas revealed no significant change in correlation coefficients and estimate performance.

In order to profit from the TMPA combination product on a daily basis, a procedure to blend it with daily precipitation gauge measurements is proposed.

Different sources of errors and uncertainties introduced by the sensors, sensor

Andes: An Intelligent Homework System for Introductory Physics

Science.gov (United States)

van de Sande, Brett; VanLehn, K.; Hausmann, R.; Treacy, D.; Shelby, R.

2006-12-01

We know that students benefit from solving homework problems under the guidance of an expert (human) tutor. The Andes system (http://www.andes.pitt.edu) is designed for students to solve homework problems under the guidance of an expert computer tutor. Andes encourages students to use sound problem solving techniques and provides immediate right/wrong feedback on each step of a solution. On request, Andes also provides hints based on previous student actions. I will discuss how Andes works, from a student's perspective, and summarize research that demonstrates its effectiveness as a pedagogical tool. I will also discuss how Andes can function as a tool for conducting educational research, presenting an investigation of students' hint usage as an example.

Posibles efectos en la salud asociados con la metalurgia precolombina.

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Alvaro Javier Idrovo

2005-09-01

Full Text Available En el Viejo Mundo algunos investigadores piensan que los efectos adversos en la salud relacionados con la exposición a arsénico influyeron para que se cambiara de usar aleaciones de cobre con arsénico a otras menos tóxicas. En este artículo se evalúa esta hipótesis para las tres grandes tradiciones metalúrgicas precolombinas: Andes centrales, área intermedia y occidente mexicano. Los artefactos metálicos revelan que las concentraciones de arsénico en los Andes centrales fueron similares a las del Viejo Mundo (0,5% a 1%, en el área intermedia los valores eran muy inferiores, mientras en el occidente mexicano fueron muy superiores (7% a 25%. En los Andes centrales se observó inicialmente el uso de bronce arsenical, pero rápidamente se conocieron las aleaciones de cobre-estaño; estas últimas fueron cada vez más preferidas y difundidas por todo el imperio inca. Las evidencias, osteológicas y en objetos artísticos, de amputaciones de los pies entre individuos moches de los Andes centrales apoyan la idea de la presencia de la ?enfermedad del pie negro? entre las poblaciones precolombinas. En conclusión, es posible que los efectos nocivos del arsénico se hayan observado en el Nuevo Mundo, y favorecido el cambio hacia aleaciones menos tóxicas. Se requieren nuevos estudios específicos para verificar esta hipótesis.

A further contribution to the knowledge of two inadequately known species of geophilid centipedes from the Andes of South-Central Chile, currently assigned to the genus Plateurytion Attems, 1909 (Chilopoda: Geophilomorpha).

Science.gov (United States)

Pereira, Luis Alberto

2015-10-06

Two poorly known species of geophilid centipedes from the Andes of South-Central Chile, i.e., Plateurytion mundus (Chamberlin, 1955) and Plateurytion zapallar (Chamberlin, 1955) (Myriapoda: Chilopoda: Geophilomorpha), are herein redescribed and illustrated after type specimens of both taxa and new material of the latter, rectifying the condition of the coxosternites of the second maxillae, which are medially joined through a narrow, hyaline and non-areolate membranous isthmus only (instead of "broadly fused as in Pachymerium", as stated by Chamberlin), this being consistent with the current generic assignment of these species under Plateurytion Attems, 1909. New data on many morphological features of specific value, until now unknown, are also given for both taxa. Plateurytion zapallar is reported for the first time from Coquimbo region, 11 Km N of Los Vilos (Elqui province), Valparaíso region, Quebrada Huaquén, Pichicuy (Petorca province), La Campana National Park (Quillota province), and Quebrada el Tigre, Cachagua (Valparíso province). A key for identification of the South American species currently included in Plateurytion is given.

Energy problems of the central systems of air conditioning; Problemas energeticos de los sistemas centrales de climatizacion

Energy Technology Data Exchange (ETDEWEB)

Cardero Corria, Gaspar [Cubanacan, S.A., Varadero (Cuba)

2003-07-01

The central systems of air conditioning are widely used in air conditioning production for several reasons among which excel: 1) Better aesthetic of the building, 2) Less noise in the air conditioning premises and 3) Greater yield of the consumed energy. This is indeed the third reason in which this paper will try to contribute with elements that will allow reveal the problem and to identify some possible causes that originate it. The centralized systems of air conditioning must produce conditioned air with lesser power cost than the individual systems, it is that saving which allows to recover an investment that normally surpasses them in 3 to 5 times. Nevertheless, the real numbers do not demonstrate that. [Spanish] Los sistemas centrales de climatizacion son ampliamente usados en la produccion de aire acondicionado por varias razones entre las que sobresalen: 1) Mejor estetica del edificio, 2) Menor ruido en los locales climatizados y 3) Mayor rendimiento de la energia consumida. Es precisamente la tercera razon en la cual este trabajo intentara aportar elementos que permitan develar el problema e identificar algunas posibles causas que lo originan. Los sistemas centralizados de climatizacion deben producir aire acondicionado con un menor gasto energetico que los sistemas individuales, es precisamente ese ahorro lo que permite recuperar una inversion que normalmente los supera en 3 a 5 veces. Sin embargo, los numeros reales no demuestran eso.

Algunos aspectos relacionados con los riesgos en una central de esterilización

OpenAIRE

Méndez Hernández, Mirla

2004-01-01

Se muestran los riesgos que están presente en una central de esterilización y su relación con la bioseguridad. Se identifican los diferentes tipos de riesgo y se hace una descripción de cada uno de ellos. Para obtener la información se utilizó la observación, como fuente primaria y los registros existentes como fuente secundaria. Los riesgos que se pueden presentar en una central de esterilización son de tipo biológico, físico, químico y los condicionados por factores humanos y ambientales. E...

Caracterización de semillas de lupino (Lupinus mutabilis sembrado en los Andes de Colombia

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Ortega-David Eduar

2010-03-01

Full Text Available En este trabajo se identificaron las propiedades físicas, composicionales y fisicoquímicas de la semilla de Lupino (Lupinus mutabilis cultivado en Nariño (Andes de Colombia. Su composición se determinó realizando análisis proximales de semilla completa, tegumento y cotiledones. Además se determinó el contenido de minerales y su composición elemental. Se estableció cuantitativamente el contenido de alcaloides presentes y su perfil composicional. Se determinaron propiedades físicas como la forma y el tamaño de la semilla. Se determinaron las propiedades fisicoquímicas como la capacidad de retención de agua y el pH. Las cantidades de nutrientes de la semilla son menores que los valores reportados en la literatura. Se presenta una variación en cuanto al perfil de alcaloides, siendo la esparteína la segunda sustancia de mayor presencia. La hidratación de la semilla conduce a un incremento de 1.72 veces su tamaño original. Se puede sugerir que la proteína posee afinidad hidrofílica evidenciada por la elevada capacidad de retención de agua de la semilla. La identificación de estas propiedades permite reconocer el potencial de la semilla para su futuro aprovechamiento.

Early Tertiary Exhumation, Erosion, and Sedimentation in the Central Andes, NW Argentina

Science.gov (United States)

Carrapa, B.; Decelles, P. G.; Gerhels, G.; Mortimer, E.; Strecker, M. R.

2006-12-01

Timing of deformation and resulting sedimentation patterns in the Altiplano-Puna Plateau-Eastern Cordillera of the southern Central Andes are the subject of ongoing controversial debate. In the Bolivian Altiplano, sedimentation into a foreland basin system commenced during the Paleocene. Farther south in the Puna and Eastern Cordillera of NW Argentina, a lack of data has precluded a similar interpretation. Early Tertiary non-marine sedimentary rocks are preserved within the present day Puna Plateau and Eastern Cordillera of NW Argentina. The Salar de Pastos Grandes basin in the Puna Plateau contains more than 2 km of Eocene alluvial and fluvial strata in the Geste Formation, deposited in close proximity to orogenic source terrains. Sandstone and conglomerate petrographic data document Ordovician quartzites and minor phyllites and schists as the main source rocks. Detrital zircon U-Pb ages from both the Geste Formation and from underlying Ordovician quartzite cluster in the 900-1200 Ma (Grenville) and late Precambrian-Cambrian (Panafrican) ranges. Sparse late Eocene (~37-34 Ma) grains are also present; their large size, euhedral shape, and decreasing mean ages upsection suggest that these grains are volcanogenic (i.e. ash fall contamination), derived from an inferred magmatic arc to the west. The Eocene ages corroborate mammalian paleontological dates, defining the approximate begin of deposition of the Geste Formation. Alternatively, these young zircons could be of plutonic origin; however, no Eocene plutons are present in the surrounding source rocks and this interpretation is not likely. From W to E, fluvial rocks of the Quebrada de los Colorados Formation show similar sedimentological features as those observed for the Geste Formation, suggesting a genetic link between the two. Detrital zircon U-Pb data show mainly Panafrican ages, with sparse ages in the 860-935 Ma range and a few mid-Proterozoic ages. More importantly, a significant number of late Eocene

Recuperación de la biomasa mediante la sucesión secundaria, Cordillera Central de los Andes, Colombia

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Jorge Ignacio del Valle

2011-09-01

Full Text Available En bosques secundarios premontanos tropicales es escasa la información sobre el tiempo requerido para recuperar la biomasa aérea y subterránea de los primarios. Por lo tanto, establecimos 33 parcelas de 0.1ha entre 550 y 1 700m en bosques secundarios que cubrían estadios serales de 3 a 36 años y estimamos la biomasa de las plantas y de las raíces gruesas con ecuaciones locales. Así como la biomasa de las pasturas y barbechos por cosecha de 54 y 18 parcelas, respectivamente. También se calculó la edad de las parcelas con informantes locales, sensores remotos, C14 y anillos de crecimiento. En cada parcela medimos la biomasa aérea viva por hectárea (Bav y la de las raíces gruesas por hectárea (Brg. Modelamos la Bav y Brg en función de la edad mediante la ecuación de von Bertalanfy con asíntotas de 247t/ha (Bav y 66t/ha (Brg resultantes de la medición de 33 parcelas de 0.1ha en los bosques primarios. Con la razón Brg/Bav=f(t estimamos 87 años para que los bosques secundarios recuperen la Bav existente en los primarios y 217 años para recuperar la Brg. La tasa máxima de crecimiento instantáneo de la Bav fue 6.95t/ha/año a los 10 años y la tasa media máxima de crecimiento 6.26t/ha/año a los 17 años. La media ponderada de la tasa de crecimiento absoluto de la Bav alcanzó 4.57t/ha/año y la relativa 10% anual. La razón Brg/Bav inicialmente aumenta muy aceleradamente hasta 4-5 años (25%, luego disminuye hasta 25 años (18% para luego incrementar hasta 26.7

Seismicity, fault plane solutions, depth of faulting, and active tectonics of the Andes of Peru, Ecuador, and southern Colombia

Science.gov (United States)

Suarez, G.; Molnar, P.; Burchfiel, B. C.

1983-01-01

The long-period P waveforms observed for 17 earthquakes in the Peruvian Andes during 1963-1976 are compared with synthetic waveforms to obtain fault-plane solutions and focal depths. The morphological units of the Peruvian Andes are characterized: coastal plains, Cordillera Occidental, altiplano and central high plateau, Cordillera Oriental, and sub-Andes. The data base and analysis methodology are discussed, and the results are presented in tables, diagrams, graphs, maps, and photographs illustrating typical formations. Most of the earthquakes are shown to occur in the transition zone from the sub-Andes to the Cordillera Oriental under formations of about 1 km elevation at focal depths of 10-38 km. It is suggested that the sub-Andean earthquakes reflect hinterland deformation of a detached fold and thrust belt, perhaps like that which occurred in parts of the Canadian Rockies. From the total crustal shortening evident in Andean morphology and the shortening rate of the recent earthquakes it is estimated that the topography and crustal root of the Andes have been formed during the last 90-135 Myr.

Angiosperm flora and biogeography of the páramo region of Colombia, northern Andes

NARCIS (Netherlands)

Londoño, C.; Cleef, A.; Madriñan, S.

2014-01-01

Páramo is the neotropical high elevation ecosystem in the northern Andes and Central America consisting of multiple dissected open areas above 3000 m a.s.l. Complex evolutionary processes that occurred within these ecosystems gave rise to a unique tropical Andean flora. Previous phytogeographical

Organización territorial de los antiguos mayas de Belice Central

DEFF Research Database (Denmark)

Helmke, Christophe; Awe, Jaime

2008-01-01

Los modelos propuestos para la organización territorial de los mayas del período clásico en Belice Central difieren significativamente de un investigador a otro. Debido a la escasez de datos jeroglíficos, la mayoría de los modelos se han formulado teniendo en cuenta tan solo datos arqueológicos y...... se centran predominantemente sobre cada sitio investigado. Las exploraciones en Belice Central de las cuatro últimas décadas, sin embargo, han sacado a la luz numerosas piezas clave que aportan datos epigráficos, incluyendo “Glifos Emblema”. Vistos en conjunto, los datos arqueológicos y epigráficos...... proporcionan una posición más ventajosa en la determinación de la estructura del paisaje socio-político del Período Clásico del Valle de Belice. Udgivelsesdato: 2008...

Ecología y ocupación del espacio en los Andes Tropicales durante los últimos veinte milenios

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1973-01-01

Full Text Available Les Andes tropicales sont constituées par un ensemble de facettes écologiques dont le nombre est fonction du volume montagneux, du régime thermique a la base, de la diversité des modelés, du stock floristique, des effets de façade et d'abri, des modalités d'utilisation de l'espace. L'utilisation de ces facettes par les sociétés d'abord non agricoles, ensuite agricoles, a été très différente. Dans cette zone climatique les changements du climat au cours du Quaternaire ont moins affecté le milieu qu'aux latitudes moyennes, a l'exception des cotes touchées par les variations eustatiques. Aussi, une remarque importante est la constance de l'habitat au cours des 20 derniers millénaires, variant cependant en fonction des diverses facettes écologiques dont le comportement était différent suivant les modifications climatiques. Les glaciations dans les Andes sont relativement synchrones de celles des montagnes des latitudes moyennes, au moins pour le Quaternaire récent elles seraient dues a une meilleure distribution des précipitations au cours de l'année, a une nébulosité plus constante et a un abaissement des températures compris entre 5 et 9º. Les avancées glaciaires entre 20.000 et 16.000 et 14.000 et 10.000 ans BP ont eu des conséquences diverses suivant les milieux humides ou secs et les effets de dominance (en général glace au dessus de 4.000 m mais, jusque vers 2.900 m en Colombie et seulement 4.800 m dans les Andes sèches. Des processus périglaciaires se développent sur 1.000-1.500 m en contrebas dans les Andes sèches alors qu'ils n'affectent qu'une marge très étroite dans les Andes humides (500 m. L'englacement n'a jamais constitué une coupure dans la circulation N-S dans les Andes. Si la haute montagne entre 5 et 10º S était difficilement franchissable, les vallées et bassins intra andins situés entre 1.500 et 3.400 m étaient tièdes, avec une humidité mieux répartie durant l'année, moins secs qu

Investigating Crustal Scale Fault Systems Controlling Volcanic and Hydrothermal Fluid Processes in the South-Central Andes, First Results from a Magnetotelluric Survey

Science.gov (United States)

Pearce, R.; Mitchell, T. M.; Moorkamp, M.; Araya, J.; Cembrano, J. M.; Yanez, G. A.; Hammond, J. O. S.

2017-12-01

At convergent plate boundaries, volcanic orogeny is largely controlled by major thrust fault systems that act as magmatic and hydrothermal fluid conduits through the crust. In the south-central Andes, the volcanically and seismically active Tinguiririca and Planchon-Peteroa volcanoes are considered to be tectonically related to the major El Fierro thrust fault system. These large scale reverse faults are characterized by 500 - 1000m wide hydrothermally altered fault cores, which possess a distinct conductive signature relative to surrounding lithology. In order to establish the subsurface architecture of these fault systems, such conductivity contrasts can be detected using the magnetotelluric method. In this study, LEMI fluxgate-magnetometer long-period and Metronix broadband MT data were collected at 21 sites in a 40km2 survey grid that surrounds this fault system and associated volcanic complexes. Multi-remote referencing techniques is used together with robust processing to obtain reliable impedance estimates between 100 Hz and 1,000s. Our preliminary inversion results provide evidence of structures within the 10 - 20 km depth range that are attributed to this fault system. Further inversions will be conducted to determine the approximate depth extent of these features, and ultimately provide constraints for future geophysical studies aimed to deduce the role of these faults in volcanic orogeny and hydrothermal fluid migration processes in this region of the Andes.

Factores de riesgo ambientales y alimentarios para la fluorosis dental, Andes, Antioquia, 2015

Directory of Open Access Journals (Sweden)

Gustavo A. Posada-Jaramillo

2017-01-01

Full Text Available Objetivo: determinar los factores ambientales y alimentarios asociados a la fluorosis dental en la población de 12 a 15 años del municipio de Andes en el año 2015, para generar propuestas de intervención en salud bucal. Metodología: estudio de casos y controles, con un control por caso. Con una población de 206 adolescentes de 12 a 15 años. Criterios de selección: adolescentes con diagnóstico de fluorosis dental entre 2012 y 2014, reportados al Sistema de Vigilancia Epidemiológica; se excluyeron aquellas personas que no tuvieran dientes erupcionados en más de un 50%, restauraciones amplias o caries extensas, dientes fracturados y edentulos totales. Los casos fueron seleccionados por muestreo aleatorio simple, los controles a conveniencia. Se realizó examen clínico para clasificar según el Índice de Dean la presencia y nivel de fluorosis dental, se aplicó encuesta a los padres para indagar sobre hábitos de autocuidado, e identificar posibles fuentes de exposición a flúor. Se analizaron variables sociodemográficas, alimentarias y comportamentales, ambientales y clínicas, se utilizaron Chi2 de Pearson – or con intervalos de confianza del 95%. Se efectúo análisis de contenido de concentración de flúor en muestras de agroquímicos, alimentos, agua de consumo humano, sal, cremas dentales y suelos. Resultados: mediante regresión logística binaria usando el método stepwise los resultados mostraron una asociación entre manipulación de agroquímicos y fluorosis dental (or = 2,093; 95% 1,017 y 4,307. Conclusión: la manipulación de agroquímicos es un factor de riesgo para la aparición de la fluorosis dental en los adolescentes del municipio de Andes.

Ontogenia de los estróbilos, desarrollo de los esporangios y esporogénesis de Equisetum giganteum (Equisetaceae en los Andes de Colombia

Directory of Open Access Journals (Sweden)

Edgar Javier Rincón Barón

2011-12-01

, los núcleos y nucléolos presentan fluorescencia roja, inducida por coloración con safranina O, mientras que los eláteres y las células de la pared del esporangio presentan autofluorescencia amarillo-naranja.Ontogeny of strobili, sporangia development and sporogenesis in Equisetum giganteum (Equisetaceae from the Colombian Andes. Studies on the ontogeny of the strobilus, sporangium and reproductive biology of this group of ferns are scarce. Here we describe the ontogeny of the strobilus and sporangia, and the process of sporogenesis using specimens of E. giganteum from Colombia collected along the Rio Frio, Distrito de Sevilla, Piedecuesta, Santander, at 2 200m altitude. The strobili in different stages of development were fixed, dehydrated, embedded in paraffin, sectioned using a rotatory microtome and stained with the safranin O and fast green technique. Observations were made using differential interference contrast microscopy (DIC or Nomarski microscopy, an optical microscopy illumination technique that enhances the contrast in unstained, transparent. Strobili arise and begin to develop in the apical meristems of the main axis and lateral branches, with no significant differences in the ontogeny of strobili of one or other axis. Successive processes of cell division and differentiation lead to the growth of the strobilus and the formation of sporangiophores. These are formed by the scutellum, the manubrium or pedicel-like, basal part of the sporangiophore, and initial cells of sporangium, which differentiate to form the sporangium wall, the sporocytes and the tapetum. There is not formation of a characteristic arquesporium, as sporocytes quickly undergo meiosis originating tetrads of spores. The tapetum retains its histological integrity, but subsequently the cell walls break down and form a plasmodium that invades the sporangial cavity, partially surrounding the tetrads, and then the spores. Towards the end of the sporogenesis the tapetum disintegrates

Classification of debris-covered glaciers and rock glaciers in the Andes of central Chile

Science.gov (United States)

Janke, Jason R.; Bellisario, Antonio C.; Ferrando, Francisco A.

2015-07-01

In the Dry Andes of Chile (17 to 35° S), debris-covered glaciers and rock glaciers are differentiated from true glaciers based on the percentage of surface debris cover, thickness of surface debris, and ice content. Internal ice is preserved by an insulating cover of thick debris, which acts as a storage reservoir to release water during the summer and early fall. These landforms are more numerous than glaciers in the central Andes; however, the existing legislation only recognizes uncovered or semicovered glaciers as a water resource. Glaciers, debris-covered glaciers, and rock glaciers are being altered or removed by mining operations to extract valuable minerals from the mountains. In addition, agricultural expansion and population growth in this region have placed additional demands on water resources. In a warmer climate, as glaciers recede and seasonal water availability becomes condensed over the course of a snowmelt season, rock glaciers and debris-covered glaciers contribute a larger component of base flow to rivers and streams. As a result, identifying and locating these features to implement sustainable regional planning for water resources is important. The objective of this study is to develop a classification system to identify debris-covered glaciers and rock glaciers based on the interpretation of satellite imagery and aerial photographs. The classification system is linked to field observations and measurements of ice content. Debris-covered glaciers have three subclasses: surface coverage of semi (class 1) and fully covered (class 2) glaciers differentiates the first two forms, whereas debris thickness is critical for class 3 when glaciers become buried with more than 3 m of surface debris. Based on field observations, the amount of ice decreases from more than 85%, to 65-85%, to 45-65% for semi, fully, and buried debris-covered glaciers, respectively. Rock glaciers are characterized by three stages. Class 4 rock glaciers have pronounced

High-Resolution ∂18O record of middle-late Holocene hydrologic variability from the central Peruvian Andes (Invited)

Science.gov (United States)

Rodbell, D. T.; Abbott, M.; Bird, B. W.; Stansell, N.

2009-12-01

Laguna Yuraicocha in the western cordillera of the central Peruvian Andes (12.53°S; 75.50°W; 4460 masl) is dammed by late glacial moraines and is underlain and surrounded by Jurassic and Cretaceous limestone interbedded with siliciclastic rocks. A 6.9 meter-long sediment core from the distal end of the lake is dominated by authigenic calcite (marl) with a mean concentration of 82 weight percent that has accumulated at a rate of ~ 1 mm yr-1 for the past 6200 years. The age model for the core is based on a combination of 210Pb and AMS 14C ages from charcoal; modern lake water is ~1‰ evaporatively enriched from mean regional precipitation. Marl samples were taken with an average sampling interval of 8 years; samples were treated to remove organic matter, sieved to concentrate the clay fraction was removed by repeated pipette withdrawal. The Peru and Bolivia, are especially sensitive to changes in regional moisture balance.

The paradigm of paraglacial megafans of the San Juan river basin, Central Andes, Argentina

Science.gov (United States)

Suvires, Graciela M.

2014-11-01

The spatial distribution and several morphometric characteristics of the Quaternary alluvial fans of the San Juan River, in the province of San Juan, at the Central and Western part of Argentina, have been studied to classify them as paraglacial megafans, as well to ratify its depositional environmental conditions. The high sedimentary load exported by San Juan river from the Central Andes to the foreland depressions is estimated about 3,682,200 hm3. The large alluvial fans of Ullum-Zonda and Tulum valleys were deposited into deep tectonic depressions, during the Upper Pleistocene deglaciation stages. The outcome of collecting remotely sensed data, map and DEM data, geophysical data and much fieldwork gave access to morphometric, morphographic and morphogenetic data of these alluvial fans. The main drainage network was mapped on processed images using QGis (vers.2.0.1). Several fan morphometric parameters were measured, such as the size, the shape, the thickness, the surface areas and the sedimentary volume of exported load. The analyzed fans were accumulated in deep tectonic depressions, where the alluvium fill reaches 700 to 1200 m thick. Such fans do not reach the large size that other world megafans have, and this is due to tectonic obstacles, although the sedimentary fill average volume surpasses 514,000 hm3. The author proposes to consider Ullum-Zonda and Tulum alluvial fans as paraglacial megafans. According to the stratigraphic relationships of the tropical South American Rivers, the author considers that the San Juan paraglacial megafans would have occurred in the period before 24 ka BP , possibly corresponding to Middle Pleniglacial (ca 65-24ka BP). They record colder and more humid conditions compared with the present arid and dry conditions.

Changing Student Attitudes using Andes, An Intelligent Homework System

Science.gov (United States)

van de Sande, Brett; Vanlehn, Kurt; Treacy, Don; Shelby, Bob; Wintersgill, Mary

2007-03-01

The size of introductory physics lectures often inhibits personal homework assistance and timely corrective feedback. Andes, an intelligent homework help system designed for two semesters of introductory physics, can fill this need by encouraging students to use sound problem solving techniques and providing immediate feedback on each step of a solution. On request, Andes provides principles-based hints based on previous student actions. A multi-year study at the U.S. Naval Academy demonstrates that students using Andes perform better than students working the same problems as graded pencil and paper homeworks. In addition, student attitude surveys show that Andes is preferred over other homework systems. These findings have implications for student attitudes toward, and mastery of, physics. See http://www.andes.pitt.edu for more information.

Relación entre los factores de circulación atmosférica regional y de la cupla océano - atmósfera con los derrames extremos de los ríos San Juan y Mendoza

OpenAIRE

Poblete, Arnobio G.; Aguiar, Laura A.

2016-01-01

Dada la crisis hídrica que soporta Cuyo en la actualidad, agudizada desde 2010, resulta fundamental investigar la variabilidad temporal de los derrames anuales de los ríos de los Andes Áridos, que dependen esencialmente de la provisión de agua proveniente de un régimen nival de alta montaña, con el fin de identificar sus tendencias decrecientes y caracterizar sus periodos extremos; por ser los más perjudiciales para las actividades socioeconómicas. Los autores estudiaron la estructu...

EL ROL DEL ANTICICLÓN PACÍFICO EN LA CAÍDA DE NIEVE EN LOS ANDES ÁRIDOS

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Arnobio G. Poblete

2016-12-01

Full Text Available This article aims to study in depth the role the anticyclone subtropical eastern South Pacific (ASPSO on the nival precipitation in the arid Andes, its seasonal variability, fluctuations in the long and medium scale and associations with snowfall. For this reason, the incidence on the ratio of precipitation, the SST in the South Pacific Ocean, precipitable water, wind zonal, Radiation in Outgoing Long Wave and Omega were analyzed. The methodology consisted in the evaluation of the ASPSO through the definition of an index, based on Santiago de Chile (PSGO measured surface atmospheric pressure. This would allow its surveillance and the processing of its temporal behavior in the statistical analysis. The results showed significant time - space associations within the involved variables, which confirmed in all cases the negative impact of ASPSO related to snowfall in the Andes mountains. period 1909-2015.

A Million-Year Record of Glaciation in the Tropical Andes

Science.gov (United States)

Smith, J. A.; Seltzer, G. O.; Rodbell, D. T.; Farber, D. L.; Finkel, R. C.

2004-12-01

We present a longterm record of glaciation in the tropical Andes based on cosmogenic dating (10Be) of boulders on moraines. Well-preserved moraines in deglaciated valleys bordering the Junin Plain in central Peru ( ˜11° S, 76° W, 4000 m) were deposited during several glacial cycles extending back more than one million years before present (1 Myr BP). The presence of boulders with zero-erosion 10Be exposure ages >1 Myr constrains boulder erosion rates to relatively low values. For boulders at high altitudes, however, even low boulder erosion rates (0.3 to 0.5 m/Myr) make calculated old exposure ages markedly older [e.g., ˜20% older for a zero-erosion age of 400,000 10Be years (400 10Be kyr)]. Exposure ages recalculated with boulder erosion rates of 0.3 m/Myr straddle interglacial marine isotope stage (MIS) 11 ( ˜430-390 kyr BP), fall within glacial MIS 12 ( ˜480-430 kyr BP), but skip over glacial MIS 16 ( ˜670-630 kyr BP), perhaps the largest ice volume of the past 2 Myr. Increasing the erosion rate used in the calculations to 0.5 m/Myr moves ages into both MIS 11 and MIS 16. If we assume that the older Andean glaciations were indeed synchronous with global ice volume, our data suggest that boulder preservation cannot be treated as a simple linear process. Conversely, the data may be suggesting correctly that glaciation of the tropical Andes was not synchronous with the global glaciations as inferred from the marine isotope record. Our chronology for the last glacial maximum (LGM) in the region supports the idea of asynchrony between the global ice volume record and the terrestrial record of glaciation in the tropical Andes. The LGM in the Junin region of Peru and in the Cordillera Real of Bolivia (16° S 68° W) occurred ˜34 to 22 10Be kyr BP and was less extensive than older glaciations. Asynchrony between the LGM in the Northern Hemisphere ( ˜21 kyr BP) and the tropical Andes suggests that previous glaciations in the tropical Andes may have been

Comparación de los valores del espesor corneal central según los equipos Lenstar, Galilei y Pentacam Comparative study of the central corneal thickness measurements taken by Lenstar, Gallilei and Pentacam equipment

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Iramis Miranda Hernández

2012-06-01

Full Text Available Objetivo: Comparar valores del espesor corneal central obtenidos mediante la paquimetría con el sistema de interferometria de coherencia parcial (Lenstar con los sistemas Scheimpflug (Pentacam; Oculus y Galilei (Ziemer, Suiza. Métodos: Se realizó un estudio prospectivo, comparativo en 120 ojos de 60 pacientes. Para la comparación se tomaron varias mediciones recomendadas por los fabricantes para probar la eficacia del equipo con el nuevo biómetro Lenstar LS 900 (Haag Streit AG y con los equipos Pentacam y Galilei. La comparación de los valores se realizó mediante el análisis de regresión lineal y correlación de Pearson. Resultados: El análisis reveló que existe una alta correspondencia en los valores del espesor corneal central entre Lenstar y los topógrafos Galilei y Pentacam. Conclusiones: Existe una alta correspondencia entre los valores del espesor corneal central obtenidos por los equipos Lenstar, Pentacam y Galilei. Por esto el equipo Lenstar es útil en la cirugía de catarata y la cirugía refractiva.Objective: To compare the central corneal thickness measurements taken by pachimetry with the partial coherence interferometry, Lenstar and with Scheimpflug systems (Pentacam; Oculus and Galilei (Ziemer, Switzerland. Methods: Comparative and prospective study of 120 eyes from 60 patients. Several recommended measurements were taken with the optical biometers LenstarLS 900 (Haag Streit AG and with Pentacam y Galilei topographers. The results were evaluated using the linear regresión analysis and Pearson´s correlation. Results: There is high correlation among the central corneal thickness measurements taken by the Lenstar equipment and topographers Pentacam and Galilei. Conclusion: The new biometer LENSTAR provided results that correlated very well with those of the Pentacam and Galilei systems. The Lenstar is a precise device that will be helpful for any cataract or refractive surgery.

Les régimes thermiques et pluviométriques de Pachachaca (Andes Centrales du Pérou: contribution à la connaissance des rythmes saisonniers dans le climat de la Puna

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1983-01-01

Full Text Available A partir des données thermiques et pluviométriques fournies par la station de Pachachaca, on tente de définir les rythmes saisonniers du climat de la Puna vers 4000 m. d'altitude. Trois saisons s'individualisent nettement: une saison sèche de 4 mois, une saison de début des précipitations de septembre à décembre, et les mois très pluvieux (janvier à mars. La variabilité des températures tout au long de la série trentenaire, est due principalement à celle des minima une tendance au réchauffement des minima s'est dessinée récemment depuis les années 1965. La dispersion des totaux pluviométriques est forte depuis 1943 et des changements tendanciels peuvent intervenir la saison sèche est toujours très marquée relativement, par contre la saison humide peut connaître de fortes fluctuations, au niveau des totaux accumulés, mais aussi de la répartition mensuelle des précipitations: une tendance récente a vu l'accroissement sensible des chutes de début de saison humide, au détriment de celles du maximum des pluies. On s'interroge sur l'extension possible de ces remarques à l'ensemble des hautes Andes du Pérou. A partir de los datos térmicos y pluviométricos dados por la estación de Pachachaca, se trata de determinar los ritmos estacionales del clima de la Puna cerca de los 4000 metros s.n.m. Tres períodos se destacan de una manera clara: uno seco de cuatro meses, uno de principio de precipitaciones desde setiembre hasta diciembre, y finalmente los meses con mucha lluvia (enero-marzo. La variabilidad de las temperaturas durante toda la serie de treinta años es principalmente la consecuencia de las mínimas una tendencia al recalentamiento de las mínimas se ha destacado recientemente, desde los años 1965. La dispersión de los totales pluviométricos es fuerte desde 1943 (año de inicio de la serie y algunos cambios de tendencia pueden ocurrir la temporada seca es siempre relativamente muy marcada, pero al contrario la

Una ruina habitada desde el presente: vestigios del horror, la resistencia y el duelo. A propósito de La Ilíada de Teatro de los Andes (2000

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María Gabriela Aimaretti

2016-12-01

Full Text Available Este trabajo describe y analiza la obra La Ilíada (2000 de Teatro de los Andes que, retomando el texto homérico desde el contexto boliviano y latinoamericano, ofrece una interpretación crítica del pasado reciente de las dictaduras cívico-militares y el presente neoliberal. Esa lectura es posible gracias al diseño de una compleja arquitectura discursiva, visual, lingüística —con apelación al quechua y español– y musical —combinando tradiciones vernáculas y europeas–, que reelabora numerosos y variados intertextos. Nutrido de los aportes de la crítica cultural latinoamericana y los estudios de la memoria, y considerando el marco socio-histórico en el que se inserta y con el que discute la obra; este ensayo reflexiona sobre las formas de representación del dolor y la violencia, y las prácticas de la resistencia y de duelo, a propósito de un espectáculo que se postula a sí mismo como la memoria de un pasado-presente traumático del cual es necesario aprender.

Lacustrine sedimentation in an altitude forest site, central Andes, Bolivia. Palaeo-climatic implications

International Nuclear Information System (INIS)

Sifeddine, A.; Bertaux, J.; Mourguiart, Ph.; Disnar, J.R.; Laggoun-Defarge, F.; Argollo, J.

1998-01-01

A sedimentological study of a 755 cm length core sampled in the middle of a marshy depression surrounded by a cloud forest in the central Andes reveals that this site has recorded important environmental variations during the last 50 000 years. For the most part (625 cm) the core is composed of detrital rich sediments deposited during the Upper Pleistocene. The highest amount of detrital influx underlines the Last Glacial Maximum which ranges from ca 29,000 14 C yr B.P. to ca 16,000 14 C yr B.P. (ca 18,500 cal yr B.P.), between two relatively humid phases. The sedimentation of the present Interglacial, starting at ca 12,500 14 C yr B.P. (14,500 cal yr B.P.), is mainly organic, as a consequence of the great development of soils and the forest vegetal cover the catchment area. The maximum extension of this vegetal cover ranging from 12,500 to ca 10,500 14 C yr B.P. (14,500 and 12,400 cal yr B.P.) is followed from 10,500 to 8,000 14 C yr B.P. (12,400 and 8,800 cal yr B.P.) by a drier period is revealed by the occurrence of micro-charcoals in the sediment. Between ca 8,000 and 4,000 14 C yr B.P. (8,800 and 4,500 cal yr B.P.), the sharp increase of micro-charcoals content, likely related to palaeo-fires, underlines an intensification of this dry trend. (authors)

Colobanthus Quitensis (H.B.K. Bartl. (Caryophyllaceae en los Andes Colombianos

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Aguirre C. Jaime

1982-04-01

Full Text Available Colobantbus quitensis y Deschampsia antarctica son las dos únicas fanerogamas nativas presentes hoy dia en el continente antártico (Green, 1970. La primera tiene una distribución amplia en regiones templadas y frías de América Latina, desde la Tierra del Fuego hasta México (Moore, 1972.  En noviembre de 1978 se realizó una exploración geobotánica corta al Páramo Alto del Almorzadero en la Cordillera Oriental, Departamento de Santander; en el piso pantanoso de un vallecito a 3.900 m (El Tutal se encontraron algunas maticas dispersas de Colobanthus quitensis (biótipo laxa cerca de una corriente lenta de agua. El hallazgo anterior de Colobanthus quitensis en la región del Nevado del Ruiz en la Cordillera Central motivó la elaboración del presente trabajo, con el fin de dar a conocer los caracteres morfológicos, palinológicos y sociológicos de esta interesante especie.

Sindicatos y centrales sindicales en Brasil en los años 80 y 90

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Alvaro A. COMIN

2009-11-01

Full Text Available RESUMEN: El objetivo de este artículo es realizar un balance de la trayectoria de las principales centrales sindicales brasileñas en esta última década y media y reflexionar sobre los límites y posibilidades existentes para su efectiva consolidación como organismos centralizados de representación de los intereses de los trabajadores. En primer lugar, el artículo menciona algunas diferencias que separan la experiencia de la formación de las centrales sindicales en los países desarrollados y en Brasil. Posteriormente se analizan el proceso de formación de las centrales sindicales, los principales clivages que determinan la división del movimiento sindical en el inicio de los años 80 y la trayectoria de las principales centrales a lo largo de aquella década. En el siguiente punto, se presenta un cuadro corporativo de las dos principales centrales (CUT y FS que polarizan la escena en los años 90. Finalmente, se concluye con algunas especulaciones sobre las posibilidades de cambio en el interior del cuadro jurídico-institucional que regula la actual estructura de las relaciones capital-trabajo y de la organización sindical en Brasil y sus consecuencias en términos de consolidación de las centrales sindicales.ABSTRACT: The goal of this article is to make a historical balance of the main brazilean trade unions in the last ten years. The author deals about its possibilities to fit its function: to represent the interest of workers. At first time, it is mentioned some differences between the experiences of brazilean trade unionsand the european ones. Then, the author analyzes the process of formation and history of brazilean trade unions and the main cleavages of these ones during the eighties. The next item is a comparative analysis of the two main trade unions (CUT an FS during the nineties. Finally, the article finishes with some reflections about the possibilities of change within the rules between capital and work in Brazil.

Central Chile

Science.gov (United States)

2002-01-01

The beginning of spring in central Chile looked like this to SeaWiFS. The snow-covered Andes mark the country's eastern border, and phytoplankton blooms and river sediment plumes fill the waters off its west coast. A large eddy due west of Concepcion is highlighted by the phytoplankton it contains.

Estimation de l'aléa sismique dans les Andes nord équatoriennes

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1996-01-01

Full Text Available Les Andes Nord équatoriennes ont connu de nombreux séismes historiques destructeurs. Pour caractériser l’aléa sismique de la région andine, nous avons fait une révision critique de la sismicité historique et de l’ensemble des failles actives de l’Équateur. Les deux sources majeures de l’aléa sismique sont respectivement la subduction superficielle pour la région côtière et le système transpressif des hautes Andes pour la région andine. Ce système est composé de failles décrochantes dextres d’orientation N30-35°E (failles du Rio Chingual-La Sofia et Pallatanga qui limitent respectivement au Nord et au Sud des failles inverses N-S du relais compressif de la vallée interandine (failles de Quito et de Latacunga. L’étude des mécanismes au foyer superficiels des Andes équatoriennes nous a permis de calculer une vitesse de raccourcissement crustal de 4.6 mm/a selon une direction N92°E et d’estimer des temps de récurrence et des périodes de retour. Un séisme de Mw = 5 pourrait se produire tous les 0.5 an, de Mw = 6 tous les 4.5 ans, de Mw = 7 tous les 45.4 ans. De même, sur une période de temps de 33 ans, 66 séismes de Mw=5 peuvent être attendus, 7 séismes de Mw=6 et 1 séisme de Mw=7. Enfin, nous avons estimé pour l’ensemble des sources sismogènes de la région andine des magnitudes maximales probables et des temps de récurrence. Un séisme de magnitude 7 à 7.5 peut se produire sur la faille du Rio Chingual tous les 400±440 ans et de magnitude 6.7 à 7.2 tous les 380±320 ans sur la faille de Pallatanga. Dans la vallée interandine, la faille de Quito est susceptible d’engendrer un séisme de magnitude 6.6 à 7.6 tous les 930±300 ans. LA AMENAZA SÍSMICA EN LOS ANDES ECUATORIANOS. Los Andes del Norte del Ecuador son una región sismogénica mayor, donde se puede contabilizar muchos terremotos históricos destructores. A fin de determinar la amenaza sísmica sobre la región andina, se hizo la asociaci

First evidence of tumor-like anomaly infestation in Copepods from the central Indian Ridge

Digital Repository Service at National Institute of Oceanography (India)

Bhandare, C.; Ingole, B.S.

manuscript. This is the contribution No. 4338 of NTO, Goa. References 1 Peralta P & Claps M. Plankton of a high mountain shallow lake (Los Horcones, High Los Andes Cordillera, Mendoza, Argentina). Verhandlungen der Int. Vereinigung fuer Theoretische und...

Historia, mito, memoria: armas del presente y pilares de identidad. La política de la memoria. Interpretación indigena de la historia de los Andes Colombianos

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Sonia M. Jaimes

2002-01-01

Full Text Available Historia, mito, memoria: armas del presente y pilares de identidad Joanne Rappaport, La Política de la Memoria. Interpretación Indígena de la Historia en los Andes Colombianos. Popayán: Editorial Universidad del Cauca-Serie Estudios Sociales, 2000. Traducción de José Ramón Martín. Pp: 260. Entre 1978 Y1982 la antropóloga norteamericana Joanne Rappaport visitó la región del Suroccidente colombiano con el propósito de llevar a cabo una investigación sobre la concepción del espacio sagrado de una comunidad indígena. Su objeto de estudio: los paeces, hoy conocidos como Nasa nombre que apela a una reivindicación identitaria ancestral. De acuerdo a Rappaport remitirse al estudio de una comunidad indígena, exige que el ejercicio se haga bajo una mirada de carácter «totalizante», en gran medida por la estructura misma del pensamiento y la cosmovisión indígena.

Uplift sequence of the Andes at 30°S: Insights from sedimentology and U/Pb dating of synorogenic deposits

Science.gov (United States)

Suriano, J.; Mardonez, D.; Mahoney, J. B.; Mescua, J. F.; Giambiagi, L. B.; Kimbrough, D.; Lossada, A.

2017-04-01

The South Central Andes at 30°S represent a key area to understand the Andes geodynamics as it is in the middle of the flat slab segment and all the morphotectonic units of the Central Andes are well developed. This work is focused in the proximal synorogenic deposits of the Western Precordillera, in the La Tranca valley, in order to unravel the uplift sequence of this belt. Nine facies associations were recognized; most of them represent piedmont facies with local provenance from Precordillera and were deposited in the wedge-top depozone, as is expected for proximal sinorogenic deposits. However there are intercalations of transference fluvial systems, which show mixed provenance indicating that Permo-Triassic igneous rocks were already exposed to the west (Frontal Cordillera). There are also lacustrine deposits which are interpreted as the result of damming by fault activity at east of the studied basin. Finally, two maximum depositional ages at ca. 11 Ma and 8 Ma of these deposits indicate that the onset of uplift of the Precordillera at 30°S is little older than 11 Ma. These data change two previous ideas about the evolution of the Precordillera: its uplift at 30° S is younger than proposed by previous works and it is nearly synchronous along strike.

Los programas de transferencias condicionadas: ¿hacia la inclusión ...

International Development Research Centre (IDRC) Digital Library (Canada)

2011-01-03

Jan 3, 2011 ... ... is an economist and graduate student at the Universidad de los Andes. ... Call for proposals: Innovations for the economic inclusion of marginalized youth ... issue profiling evidence to empower women in the labour market.

Snakes of an urban-rural landscape in the central Andes of Colombia: species composition, distribution, and natural history

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Julián Andrés Rojas-Morales

2012-12-01

Full Text Available From 2005 to 2011, I studied the composition, distribution and natural history of an Andean urban-rural snake assemblage at the Cordillera Central of Colombia, based on three data sources: (1 examination of specimens in the MHN-UC [Museo de Historia Natural, Universidad de Caldas], (2 incidental encounters by author, and (3 collection of data by other researchers. Additionally, I provide natural history notes for the species involved. A total of 14 species, including two subspecies of snakes, belonging to 12 genera and four families, have been found in the studied area (municipality of Manizales, Caldas. Taking into account this total, 10 had atleast one record in the urban area, 13 in the rural area and 14 in forested areas. Only Liophis epinephelus bimaculatus was found exclusively in forest environment. Three species (21.4% are apparently endemic to the region, six species (42.8% correspond to afauna representative of the Tropical–Andean range of South America, four species (28.5% are distributed from Central America to the tropical Andes, and only one species is widely distributed in the whole continent. The snake assemblage in Manizales is mostly terrestrial, and in general, the species tend to be more active in the rainy periods of the year (mainly from October–December, and most of them may occasionally be found in urban areas, mainly close to areas of vegetation such as crops and pastures.

Aplicación de tres índices bióticos en el río San Juan, Andes, Colombia (Application of three biotic indexes in the river San Juan, Andes, Colombia

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Mailedt Paola Murillo Torrentes

2016-09-01

Full Text Available Durante los meses de febrero, mayo, agosto y octubre del año 2014, se evaluó la calidad del agua del río San Juan. Para tal fin se establecieron seis puntos de muestreo donde se recolectaron muestras de agua y macroinvertebrados acuáticos para los análisis fisicoquímicos e hidrobiológicos. Se aplicaron y modificaron los índices bióticos EPT (efemerópteros, plecópteros, tricópteros, BMWP/Col (Biological Monitoring Working Party y ASPT (Average Score per Taxon basados en las comunidades de macroinvertebrados acuáticos capturados. Los resultados de las variables fisicoquímicas y los índices bióticos indican que las estaciones E1 y E2 son las que presentan menor grado de contaminación, en las demás estaciones disminuye considerablemente la calidad del agua debido a las actividades económicas desarrolladas en el sector y a su cercanías con el casco urbano del municipio de Andes. De los tres índices analizados, el ASPT modificado y adaptado al río San Juan es el que mejor se relaciona con las condiciones ambientales del río en tanto las características de los macroinvertebrados acuáticos recolectados y analizados en el trayecto objeto de estudio. (Abstract. During the months of February, May, August and October 2014, the water quality of the San Juan River was assessed. To this aim, six sampling points were established, where water samples and macroinvertebrates for physical-chemical and hydrobiological analysis were collected. Three biotic indexes were applied and one modified: EPT (Ephemeroptera, Plecoptera, Trichoptera, BMWP / Col (Biological Monitoring Working Party and ASPT (Average Score per Taxon based on the captured communities of aquatic macroinvertebrates. The results of the physical-chemical variables and biotic indixes indicate that E1 and E2 stations are those with lower degree of contamination, other stations considerably decreased water quality due to economic activities around, and the short distance with the

How do two Lupinus species respond to temperature along an altitudinal gradient in the Venezuelan Andes? ¿Cómo responden dos especies de Lupinus a la temperatura en un gradiente altitudinal en los Andes venezolanos?

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FERMÍN RADA

2008-09-01

Full Text Available Temperature determines plant formations and species distribution along altitudinal gradients. Plants in the tropical high Andes, through different physiological and morphological characteristics, respond to freezing night temperatures and high daytime energy inputs which occur anytime of the year. The main objective of this study was to characterize day and night temperature related responses of two Lupinus species with different altitudinal ranges (L. meridanus, 1,800-3,600 and L. eromonomos, 3,700-4,300 m of altitude. Are there differences in night low temperature resistance mechanisms between the species along the gradient? How do these species respond, in terms of optimum temperature for photosynthesis, to increasing altitude? Lupinus meridanus shows frost avoidance, in contrast to L. eromonomos, which tolerates freezing at higher altitudes. Optimum temperature for photosynthesis decreases along the gradient for both species. Maximum C0(2 assimilation rates were higher in L. meridanus, while L. eromonomos showed decreasing C0(2 assimilation rates at the higher altitude. In most cases, measured daily leaf temperature is always within the 80 % of optimum for photosynthesis. L. meridanus7 upper distribution limit seems to be restricted by cold resistance mechanisms, while L. eromonomos7 to a combination of both cold resistance and to C0(2 assimilation responses at higher altitudes.La temperatura determina las formaciones vegetales y la distribución de especies a lo largo de gradientes altitudinales. Las plantas en los altos Andes tropicales, a través de diferentes características morfológicas y fisiológicas, responden a temperaturas congelantes nocturnas y altas entradas energéticas durante el día en cualquier momento del año. El objetivo principal de este estudio fue caracterizar las respuestas relacionadas con temperaturas diurnas y nocturnas en dos especies de Lupinus con diferente distribución altitudinal (L. meridanus, 1

Lo colectivo y el agua: entre los derechos y las prácticas

NARCIS (Netherlands)

Bustamante Zenteno, R.R.

2010-01-01

Reseña: La reivindicación de los derechos colectivos ha sido parte importante de las luchas de las organizaciones sociales que gestionan el agua en los Andes. Las formas de lo colectivo y las reglas en torno a su constitución están muy vinculadas a la existencia de estas organizaciones y a la

El desarrollo de los cibermedios venezolanos

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Elías Said Hung

2012-01-01

Full Text Available En esta investigación se analizan 68 medios digitales en Venezuela, a partir de los resultados obtenidos entre octubre y noviembre de 2010, en el marco del proyecto "Los Cibermedios en Colombia y América Latina", realizado desde la Universidad del Norte, con el apoyo de la Universidad de los Andes (Venezuela, con el fin de determinar el grado de adopción del ciberperiodismo y de las web 2.0 en este país. El estudio parte del modelo de análisis propuesto por Rodríguez-Martínez, Codina y Pedraza-Jiménez (2010. Los resultados apuntan a un bajo desarrollo de los cibermedios en Venezuela y la necesidad de un profundo debate y acciones orientadas al aprovechamiento de las potencialidades de las TIC desde los medios digitales en dicho país.

A paleolimnological perspective on industrial-era metal pollution in the central Andes, Peru.

Science.gov (United States)

Cooke, Colin A; Abbott, Mark B

2008-04-15

To date, few studies have investigated the environmental legacy associated with industrialization in the South American Andes. Here, we present an environmental archive of industrial pollution from (210)Pb-dated lake cores recovered from Laguna Chipian, located near the Cerro de Pasco metallurgical region and Laguna Pirhuacocha, located near the Morococha mining region and the La Oroya smelting complex. At Laguna Chipian, trace metal concentrations increase beginning ~1900 AD, coincident with the construction of the central Peruvian railway, and the rapid industrial development of the Cerro de Pasco region. Trace metal concentrations and fluxes peak during the 1950s before subsequently declining up-core (though remaining well above background levels). While Colonial mining and smelting operations are known to have occurred at Cerro de Pasco since at least 1630 AD, our sediment record preserves no associated metal deposition. Based on our (14)C and (210)Pb data, we suggest that this is due to a depositional hiatus, rather than a lack of regional Colonial pollution. At Laguna Pirhuacocha, industrial trace metal deposition first begins ~1925 AD, rapidly increasing after ~1950 AD and peaking during either the 1970s or 1990s. Trace metal concentrations from these lakes are comparable to some of the most polluted lakes in North America and Europe. There appears to be little diagenetic alteration of the trace metal record at either lake, the exception being arsenic (As) accumulation at Laguna Pirhuacocha. There, a correlation between As and the redox-sensitive element manganese (Mn) suggests that the sedimentary As burden is undergoing diagenetic migration towards the sediment-water interface. This mobility has contributed to surface sediment As concentrations in excess of 1100 microg g(-1). The results presented here chronicle a rapidly changing Andean environment, and highlight a need for future research in the rate and magnitude of atmospheric metal pollution.

A paleolimnological perspective on industrial-era metal pollution in the central Andes, Peru

International Nuclear Information System (INIS)

Cooke, Colin A.; Abbott, Mark B.

2008-01-01

To date, few studies have investigated the environmental legacy associated with industrialization in the South American Andes. Here, we present an environmental archive of industrial pollution from 210 Pb-dated lake cores recovered from Laguna Chipian, located near the Cerro de Pasco metallurgical region and Laguna Pirhuacocha, located near the Morococha mining region and the La Oroya smelting complex. At Laguna Chipian, trace metal concentrations increase beginning ∼ 1900 AD, coincident with the construction of the central Peruvian railway, and the rapid industrial development of the Cerro de Pasco region. Trace metal concentrations and fluxes peak during the 1950s before subsequently declining up-core (though remaining well above background levels). While Colonial mining and smelting operations are known to have occurred at Cerro de Pasco since at least 1630 AD, our sediment record preserves no associated metal deposition. Based on our 14 C and 210 Pb data, we suggest that this is due to a depositional hiatus, rather than a lack of regional Colonial pollution. At Laguna Pirhuacocha, industrial trace metal deposition first begins ∼ 1925 AD, rapidly increasing after ∼ 1950 AD and peaking during either the 1970s or 1990s. Trace metal concentrations from these lakes are comparable to some of the most polluted lakes in North America and Europe. There appears to be little diagenetic alteration of the trace metal record at either lake, the exception being arsenic (As) accumulation at Laguna Pirhuacocha. There, a correlation between As and the redox-sensitive element manganese (Mn) suggests that the sedimentary As burden is undergoing diagenetic migration towards the sediment-water interface. This mobility has contributed to surface sediment As concentrations in excess of 1100 μg g -1 . The results presented here chronicle a rapidly changing Andean environment, and highlight a need for future research in the rate and magnitude of atmospheric metal pollution

ANDES: An Underground Laboratory in South America

Science.gov (United States)

Dib, Claudio O.

ANDES (Agua Negra Deep Experiment Site) is an underground laboratory, proposed to be built inside the Agua Negra road tunnel that will connect Chile (IV Region) with Argentina (San Juan Province) under the Andes Mountains. The Laboratory will be 1750 meters under the rock, becoming the 3rd deepest underground laboratory of this kind in the world, and the first in the Southern Hemisphere. ANDES will be an international Laboratory, managed by a Latin American consortium. The laboratory will host experiments in Particle and Astroparticle Physics, such as Neutrino and Dark Matter searches, Seismology, Geology, Geophysics and Biology. It will also be used for the development of low background instrumentation and related services. Here we present the general features of the proposed laboratory, the current status of the proposal and some of its opportunities for science.

Estructura y composición de las comunidades de macroinvertebrados acuáticos en ríos altoandinos del Ecuador y Perú. Diseño de un sistema de medida de la calidad del agua con índices multimétricos

OpenAIRE

Villamarín Flores, Christian Patricio

2012-01-01

[spa] En la presente tesis se muestrearon ríos sobre los 2000 msnm (ríos altoandinos tropicales) que se distribuyen en la amplia región de los Andes del Norte (Ecuador) y los Andes Centrales (Perú) en Sudamérica. El muestreo de las 123 localidades se realizó en época seca, las cuales se seleccionaron tomando en cuenta su grado de alteración, que van desde sin o poca alteración (referencia) hasta muy alterados. En una primera instancia se analizaron las carácteristicas fisicoquímicas e hid...

Phytogeography of the vascular páramo flora of Ramal de Guaramacal (Andes, Venezuela) and its ties to other páramo floras

OpenAIRE

Cuello, N.L.; Cleef, A.M.; Aymard, G.

2010-01-01

Ramal de Guaramacal is an outlier and lower elevation mountain range located at the northeastern end of the Venezuelan Andes. Phytogeographical patterns and affinities of the low altitude and wet vascular páramo flora of Ramal de Guaramacal, have been studied with emphasis in to the analysis of the floristic connections of the Guaramacal páramo flora with the neighboring dry páramos of the Sierra Nevada de Mérida and other páramo floras of the northern Andes and Central America. A total of 25...

Les effets de l’émigration paysanne dans les Andes équatoriennes : une lecture photographique

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Nasser Rebaï

2011-07-01

Full Text Available Dans les Andes équatoriennes, les effets de l’émigration paysanne sont partout visibles. Si dans la province de l’Azuay, on assiste à la diminution des superficies cultivées et à la réorganisation des tâches agricoles, on observe par ailleurs l’émergence d’une agriculture commerciale orientée vers le marché urbain régional. En procédant à la description de photographies prises à la campagne comme à la ville, nous chercherons à expliquer l’ensemble de ces mutations, avant de nous interroger plus largement sur l’avenir des exploitations familiales dans cette région.En los Andes ecuatorianos, los efectos de la migración campesina son visibles por todas partes. Si en la provincia del Azuay, se asiste a la disminución de las superficies cultivadas y a la reorganización de las tareas agrícolas, observamos por otro lado la emergencia de una agricultura comercial orientada hacia el mercado urbano regional. Procediendo a la descripción de fotografías tomadas en la campo como en la ciudad, procuraremos explicar el conjunto de estas mutaciones, antes de preguntarnos más ampliamente sobre el futuro de las explotaciones familiares en esta región.

Estudio exploratorio de los laminados de bambú Guadua angustifolia como material estructural

OpenAIRE

López,Luis Felipe; Correal,Juan Francisco

2009-01-01

Este artículo presenta los resultados de un estudio experimental, desarrollado en la Universidad de los Andes en Bogotá D.C., Colombia, acerca del potencial de los laminados de guadua (Guadua angustifolia Kunt) como material estructural. La influencia de la dirección de las fibras y de la ubicación de las láminas de guadua en las propiedades mecánicas es discutida en detalle. Los esfuerzos de diseño a compresión, tracción, corte y flexión de los laminados de guadua son comparados con los resp...

Holocene compression in the Acequión valley (Andes Precordillera, San Juan province, Argentina): Geomorphic, tectonic, and paleoseismic evidence

Science.gov (United States)

Audemard, M.; Franck, A.; Perucca, L.; Laura, P.; Pantano, Ana; Avila, Carlos R.; Onorato, M. Romina; Vargas, Horacio N.; Alvarado, Patricia; Viete, Hewart

2016-04-01

The Matagusanos-Maradona-Acequión Valley sits within the Andes Precordillera fold-thrust belt of western Argentina. It is an elongated topographic depression bounded by the roughly N-S trending Precordillera Central and Oriental in the San Juan Province. Moreover, it is not a piggy-back basin as we could have expected between two ranges belonging to a fold-thrust belt, but a very active tectonic corridor coinciding with a thick-skinned triangular zone, squeezed between two different tectonic domains. The two domains converge, where the Precordillera Oriental has been incorporated to the Sierras Pampeanas province, becoming the western leading edge of the west-verging broken foreland Sierras Pampeanas domain. This latter province has been in turn incorporated into the active deformation framework of the Andes back-arc at these latitudes as a result of enhanced coupling between the converging plates due to the subduction of the Juan Fernández ridge that flattens the Nazca slab under the South American continent. This study focuses on the neotectonics of the southern tip of this N-S elongated depression, known as Acequión (from the homonym river that crosses the area), between the Del Agua and Los Pozos rivers. This depression dies out against the transversely oriented Precordillera Sur, which exhibits a similar tectonic style as Precordillera Occidental and Central (east-verging fold-thrust belt). This contribution brings supporting evidence of the ongoing deformation during the Late Pleistocene and Holocene of the triangular zone bounded between the two leading and converging edges of Precordillera Central and Oriental thrust fronts, recorded in a multi-episodic lake sequence of the Acequión and Nikes rivers. The herein gathered evidence comprise Late Pleistocene-Holocene landforms of active thrusting, fault kinematics (micro-tectonic) data and outcrop-scale (meso-tectonic) faulting and folding of recent lake and alluvial sequences. In addition, seismically

Mallas y flujos : acción colectiva, cambio social, quinua y desarrollo regional indígena en los Andes Bolivianos

NARCIS (Netherlands)

Laguna, P.

2011-01-01

This thesis studies collective action and social change in indigenous rural organisations (IRO) in the Bolivian Andes. I focus on the effects and importance that these organisations have in the historical process of regional development as social spaces that encapsulate different projects of

The System Nobody Sees: Irrigated Wetland Management and Alpaca Herding in the Peruvian Andes

OpenAIRE

Verzijl, A.; Guerrero Quispe, S.

2013-01-01

Increasingly, attention in regional, national, and international water governance arenas has focused on high-altitude wetlands. However, existing local water management practices in these wetlands are often overlooked. This article looks at the irrigation activities of alpaca herders in the community of Ccarhuancho in the Central Andes of Peru. For more than two centuries, they have been constructing small-scale irrigation canals to maintain and expand the local wetlands, called bofedales. Th...

Una frontera casi invisible: los territorios al norte del Sistema Central en la Alta Edad Media (siglos VIII-XI

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Iñaki MARTÍN VISO

2009-12-01

Full Text Available RESUMEN: Los territorios al norte del Sistema Central no estuvieron sujetos a un dominio por parte de una autoridad centralizada entre los siglos VIII a XI. Los instrumentos del poder central, en especial la tributación y la organización episcopal, se descompusieron tras el siglo VIII y asumieron un papel determinante las estructuras de poder local, las cuales deben ser el principal objeto de estudio. A partir de su análisis, se descubre un espacio fronterizo abierto, con un dominio político informal, que es invisible para los poderes centrales. Palabras clave: Poderes Locales. Sitios de Altura. Necrópolis. Frontera. Tributación. Mozárabes.ABSTRACT: The territories at the North of the Iberian Central System were not ruled by any central authority between eighth and eleventh centuries. The main tools of the central power, especially the tribute and the episcopal organization, were broken down after the 8th century and the structures of local power, which must be studied particularly, got a very influential role. The analysis discover an opened frontier area, with an informal political control, that is invisible from the perspective of the central power

ESTUDIO DE ATAQUES DE ESCANEO DE PUERTOS BASADO EN CAPTURAS DE TRÁFICO DE ENLACES WAN (WIDE ÁREA NETWORK EN LA RED DE DATOS DE LA UNIVERSIDAD DE LOS ANDES, MÉRIDA, VENEZUELA

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Leonardo Uzcategui

2015-07-01

Full Text Available Con el continuo crecimiento de Internet y todas sus aplicaciones, desde comercio electrónico, redes sociales, hasta el Internet de las cosas (IoT = Internet of Thinks, los ataques a las redes se han vuelto más comunes y sofisticados. Por tanto, se hace necesario nuevas medidas de protección, las cuales deben ser más elaboradas y perfeccionadas para que puedan garantizar que las redes de datos operen de manera segura y así poder brindar continuidad a todos los servicios prestados; estas medidas incluyen métodos de detección y repuesta en tiempo real a los intentos de intrusión. En este artículo, se propone un estudio de ataques de escaneo de puertos y/o DoS (Denial of Service encontrados en análisis realizados a los enlaces WAN (Wide Area Network que interconectan la Universidad de los Andes (ULA, Mérida, Venezuela, con Internet, a través de la Red de Datos de la ULA, RedULA. Asimismo, se hacen comparaciones con estadísticas internacionales, así como el análisis del origen de dichos ataques y su respectiva identificación. Los resultados muestran que si bien RedULA no es víctima de paquetes mal formados, si lo es de tráfico excesivo, lo cual se presume sea producto de un malware.

El fraude académico en la universidad de los andes ¿qué, qué tanto y por qué ?

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José Fernando Mejía

2004-08-01

Full Text Available In this article we present the results of a research project in which we describe academic cheating at Universidad de los Andes and identify possible factors associated with the students' decision to cheat or not to do it. The participants were 1.194 undergraduate students who answered a survey in which they identified cheating behaviors, rated them according to how serious they considered them, admitted types of cheating committed, rated reasons that would make them cheat or stop them from doing it and evaluate different arguments related to two moral dilemmas. Ninety four percent of students admitted having committed at least one type of cheating. We found differences in types and frequencies of cheating across academic departments. Academic overload and specific types of evaluation were among the reasons most commonly mentioned for cheating. While those who rated highly heteronomic arguments were more prone to cheating, those who rated highly autonomic arguments were more prone to not cheating. However, a closer look at the relation between cheating and moral development did not lead to definite conclusions. The results made us realized that it is a severe problem that needs to be addressed, among other approaches, from a pedagogical perspective. We suggest some ideas about it.

Morphologic evolution of the Central Andes of Peru

Science.gov (United States)

Gonzalez, Laura; Pfiffner, O. Adrian

2012-01-01

In this paper, we analyze the morphology of the Andes of Peru and its evolution based on the geometry of river channels, their bedrock profiles, stream gradient indices and the relation between thrust faults and morphology. The rivers of the Pacific Basin incised Mesozoic sediments of the Marañon thrust belt, Cenozoic volcanics and the granitic rocks of the Coastal Batholith. They are mainly bedrock channels with convex upward shapes and show signs of active ongoing incision. The changes in lithology do not correlate with breaks in slope of the channels (or knick points) such that the high gradient indices (K) with values between 2,000-3,000 and higher than 3,000 suggest that incision is controlled by tectonic activity. Our analysis reveals that many of the ranges of the Western Cordillera were uplifted to the actual elevations where peaks reach to 6,000 m above sea level by thrusting along steeply dipping faults. We correlate this uplift with the Quechua Phase of Neogene age documented for the Subandean thrust belt. The rivers of the Amazonas Basin have steep slopes and high gradient indices of 2,000-3,000 and locally more than 3,000 in those segments where the rivers flow over the crystalline basement of the Eastern Cordillera affected by vertical faulting. Gradient indices decrease to 1,000-2,000 within the east-vergent thrust belt of the Subandean Zone. Here a correlation between breaks in river channel slopes and location of thrust faults can be established, suggesting that the young, Quechua Phase thrust faults of the Subandean thrust belt, which involve Neogene sediments, influenced the channel geometry. In the eastern lowlands, these rivers become meandering and flow parallel to anticlines that formed in the hanging wall of Quechua Phase thrust faults, suggesting that the river courses were actively displaced outward into the foreland.

Body size, composition, and blood pressure of high-altitude Quechua from the Peruvian Central Andes (Huancavelica, 3,680 m).

Science.gov (United States)

Toselli, S; Tarazona-Santos, E; Pettener, D

2001-01-01

Although much information is available about the effects of high altitude on physiological characteristics, less is know about its effect on body composition. In the present study, anthropometric and body composition variables were investigated in a sample of 77 adult Quechua males from the Peruvian Central Andes (Huancavelica, 3,680 m). The subjects are shorter in relation to body weight than other ethnic groups, whereas body proportions are macrocormic (indicating a long trunk relative to the lower extremities), with intermediate values of the acromial-iliac index. All skinfold thicknesses are low (approximately 15th percentiles of NHANES reference values for the triceps and subscapular skinfolds), but tend to be higher than in the other Quechua populations. Similar results are obtained when percentage fat is estimated. Somatotypes are dominant in mesomorphy with very low ectomorphy. Comparison with a sample of high-altitude Kirghiz (3,200 m), previously studied with the same methods, shows higher values in the Peruvian sample for all variables related to adiposity. The presence of low adiposity in the Quechua population could be associated with stresses of the high-altitude environment. Mean values of blood pressure are very low and there is no correlation with age.

Use of high-resolution satellite images for detection of geological structures related to Central Andes geothermal field, Chile.

Science.gov (United States)

Benavides-Rivas, C. L.; Soto-Pinto, C. A.; Arellano-Baeza, A. A.

2014-12-01

Central valley and the border with Argentina in the center, and in the fault system Liquiñe-Ofqui in the South of the country. High resolution images from the LANDSAT 8 satellite have been used to delineate the geological structures related to the potential geothermal reservoirs located at the northern end of the Southern Volcanic Zone of Chile. It was done by applying the lineament extraction technique, using the ADALGEO software, developed by [Soto et al., 2013]. These structures have been compared with the distribution of main geological structures obtained in the field. It was found that the lineament density increases in the areas of the major heat flux indicating that the lineament analysis could be a power tool for the detection of faults and joint zones associated to the geothermal fields. A lineament is generally defined as a straight or slightly curved feature in the landscape visible satellite image as an aligned sequence of pixel intensity contrast compared to the background. The system features extracted from satellite images is not identical to the geological lineaments that are generally determined by ground surveys, however, generally reflects the structure of faults and fractures in the crust. A temporal sequence of eight Landsat multispectral images of Central Andes geothermal field, located in VI region de Chile, was used to study changes in the configuration of the lineaments during 2011. The presence of minerals with silicification, epidotization, and albitization, which are typical for geothrmal reservoirs, was also identified, using their spectral characteristics, and subsequently corroborated in the field. Both lineament analysis and spectral analysis gave similar location of the reservoir, which increases reliability of the results.

Site of the First Spanish Nuclear Power Stations; Los Emplazamientos de las Primeras Centrales Nucleares Espanolas

Energy Technology Data Exchange (ETDEWEB)

Pascual, F.; Alonso, A.; Norena, S.; Sevilla, A. [Junta de Energia Nuclear, Madrid (Spain)

1967-09-15

The authors analyse and describe the sites of three Spanish nuclear power stations: the Zorita station (153 M W (e )) with a pressurized water reactor and single containment; the Santa Marfa de Garofia station (380 MW (e)), with a boiling water reactor and containment by steam condensation; and the Vandellos station (480 MW(e)), with a graphite-moderated gas-cooled reactor and integrated design of the EDF-4 type. The first two are located in the interior of the country and the third on the Mediterranean coast. The paper discusses the normal criteria and the safety considerations governing the choice of site, and points out the influence of Spanish orography on the transport of heavy equipment and hence its repercussions on the selection of power station sites. Reference is made to the experience acquired in transporting equipment for the Z-orita plant, and an analysis of the practical difficulties encountered in applying particular safety standards to the sites of stations of different types and designs is included. As the type of reactor and its containment system affect the practical value of applying particular standards which, moreover, have to be adapted to the special features of each country, safety standards for assessing power station sites should be applied in an appropriate and flexible manner. The paper describes the geological and meteorological features of the three sites and summarizes the studies carried out in these fields. It refers particularly to the hydrological studies carried out at Zorita and Santa Maria de Garofia and describes the weather stations set up at both sites, the diffusion experiments with neutcal-buoyancy balloons at Santa Maria de Garofia, and the results of these investigations. (author) [Spanish] Se analizan y describen los emplazamientos de tres centrales nucleares espanolas: la central de Zorita, de 153 MW(e), con reactor de agua a presion y sistema de contencion simple; la central de Santa Maria de Garofia, de 380 MW

Los indios cuzcos de Chile colonial : estrategias semánticas,usos de la memoria y gestión de identidades entre inmigrantes andinos (siglos XVI-XVII)1

OpenAIRE

Valenzuela-Márquez, Jaime

2010-01-01

El artículo explora la inmigración de indígenas de los Andes en Chile colonial y las estrategias que desarrollaron para insertarse en el medio urbano de Santiago. En particular, se estudia la emergencia de un gentilicio, el cuzco, como categoría de identidad, como autoreferencia construida por los mismos inmigrantes y heredada por sus descendientes, y como denominación recogida por las instancias coloniales. This article explores the immigration of Indians from the Andes in Chile colonial ...

Tectonic geomorphology of the Andes with SIR-A and SIR-B

Science.gov (United States)

Bloom, Arthur L.; Fielding, Eric J.

1986-01-01

Data takes from SIR-A and SIR-B (Shuttle Imaging Radar) crossed all of the principal geomorphic provinces of the central Andes between 17 and 34 S latitude. In conjunction with Thematic Mapping images and photographs from hand-held cameras as well as from the Large Format Camera that was flown with SIR-B, the radar images give an excellent sampling of Andean geomorphology. In particular, the radar images show new details of volcanic rocks and landforms of late Cenozoic age in the Puna, and the exhumed surfaces of tilted blocks of Precambrian crystalline basement in the Sierras Pampeanas.

El impacto del cambio climático en los glaciares del complejo volcánico Nevado Coropuna, (Cordillera Occidental de los Andes Centrales)

OpenAIRE

Ubeda Palenque, José

2010-01-01

El objetivo de la investigación ha sido evaluar el impacto del cambio climático en los glaciares del Nevado Coropuna, que en la actualidad recubren el área de cumbres de ese complejo de edificios volcánicos alcanzando una superficie de casi medio centenar de km2. El interés del trabajo de investigación se debe a tres razones principales: 1) De esas masas de hielo depende el abastecimiento de varias decenas de miles de personas; 2) El escenario de riesgo que se deduce de la localización vulner...

Volcanic deformation in the Andes

Science.gov (United States)

Riddick, S.; Fournier, T.; Pritchard, M.

2009-05-01

We present the results from an InSAR survey of volcanic activity in South America. We use data from the Japanese Space Agency's ALOS L-band radar satellite from 2006-2009. The L-band instrument provides better coherence in densely vegetated regions, compared to the shorter wave length C-band data. The survey reveals volcano related deformation in regions, north, central and southern, of the Andes volcanic arc. Since observations are limited to the austral summer, comprehensive coverage of all volcanoes is not possible. Yet, our combined observations reveal volcanic/hydrothermal deformation at Lonquimay, Llaima, Laguna del Maule, and Chaitén volcanoes, extend deformation measurements at Copahue, and illustrate temporal complexity to the previously described deformation at Cerro Hudson and Cordón Caulle. No precursory deformation is apparent before the large Chaitén eruption (VEI_5) of 2 May 2008, (at least before 16 April) suggesting rapid magma movement from depth at this long dormant volcano. Subsidence at Ticsani Volcano occurred coincident with an earthquake swarm in the same region.

Low-grade metamorphism of Cambro-Ordovician successions in the Famatina belt, Southern-Central Andes: Burial-inversion history linked to the evolution of the proto-Andean Gondwana margin Metamorfismo de bajo grado de sucesiones cambro-ordovícicas en el cinturón del Famatina, Andes Centrales de Argentina: Historia de enterramiento-exhumación ligada a la evolución del margen proto-andino de Gondwana

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Gilda Collo

2011-07-01

.Las condiciones P-T del metamorfismo de las unidades de bajo grado del cinturón del Famatina, Andes Centrales de Argentina, fueron estimadas mediante petrografía, difracción de rayos-X y microscopía electrónica. La Formación Negro Peinado (Cámbrico Medio-Superior fue afectada por un evento tectono-metamórfico asociado con un plegamiento intrafoliar intenso, para el cual se estimaron temperaturas entre 290 y 400°C (IKcis: 0,16-0,27 A°29, blástesis de biotita y homogeneidad composicional en micas dioctaédricas y presiones intermedias (parámetro b de la mica blanca: 9,010 Á y 9,035 Á. La Formación Achavil (Cámbrico Medio-Superior presenta un evento metamórfico asociado con temperaturas entre 200 y 290°C (KIcis: 0,26-0,41A°29 y condiciones de presión intermedias-bajas (parámetro b de la mica blanca: 8,972Á-9,017Á. Para las sucesiones comprendidas entre el Cámbrico Superior y el Ordovícico Medio, se identificó un patrón metamórfico de soterramiento, con una disminución progresiva en el grado metamórfico desde la Formación Volcancito hasta el Grupo Cerro Morado (ca. 490-465 Ma; IKcis: 0,31-0,69 A°29 y ausencia de cambios de tendencia ligados a las discontinuidades estratigráficas. La mica blanca y la clorita son los principales filosilicatos en las unidades más antiguas, mientras los interestratificados Ilt/Sme (R3 son casi exclusivos en las más jóvenes. El parámetro b de la mica blanca indica condiciones de presión intermedia-baja para estas unidades. Este patrón metamórfico de soterramiento presenta un marcado quiebre hacia la unidad ordovícica más joven (Formación La Aguadita, posterior a los ca. 452 Ma con temperaturas estimadas entre 270 y 330°C (IKcis: 0,28-0,19A°29 y condiciones de presión intermedias. Nuestros resultados indican que los procesos relacionados con la contracción e inversión de la cuenca durante la orogenia Oclóyica involucran en esta región al menos dos episodios metamórficos bien diferenciados y no superpuestos.

Water and sediment quality of the Lake Andes and Choteau Creek basins, South Dakota, 1983-2000

Science.gov (United States)

Sando, Steven Kent; Neitzert, Kathleen M.

2003-01-01

The Bureau of Reclamation has proposed construction of the Lake Andes/Wagner Irrigation Demonstration Project to investigate environmental effects of irrigation of glacial till soils substantially derived from marine shales. During 1983-2000, the U.S. Geological Survey collected hydrologic, water-quality, and sediment data in the Lake Andes and Choteau Creek Basins, and on the Missouri River upstream and downstream from Choteau Creek, to provide baseline information in support of the proposed demonstration project. Lake Andes has a drainage area of about 230 mi2 (square miles). Tributaries to Lake Andes are ephemeral. Water-level fluctuations in Lake Andes can be large, and the lake has been completely dry on several occasions. The outlet aqueduct from Lake Andes feeds into Garden Creek, which enters Lake Francis Case just upstream from Fort Randall Dam on the Missouri River. For Lake Andes tributary stations, calcium, magnesium, and sodium are approximately codominant among the cations, and sulfate is the dominant anion. Dissolved-solids concentrations typically range from about 1,000 mg/L (milligrams per liter) to about 1,700 mg/L. Major-ion concentrations for Lake Andes tend to be higher than the tributaries and generally increase downstream in Lake Andes. Proportions of major ions are similar among the different lake units (with the exception of Owens Bay), with calcium, magnesium, and sodium being approximately codominant among cations, and sulfate being the dominant anion. Owens Bay is characterized by a calcium sulfate water type. Dissolved-solids concentrations for Lake Andes typically range from about 1,400 to 2,000 mg/L. Whole-water nitrogen and phosphorus concentrations are similar among the Lake Andes tributaries, with median whole-water nitrogen concentrations ranging from about 1.6 to 2.4 mg/L, and median whole-water phosphorus concentrations ranging from about 0.5 to 0.7 mg/L. Whole-water nitrogen concentrations in Lake Andes are similar among the

Eocene extensional exhumation of basement and arc rocks along southwesternmost Peru, Central Andes.

Science.gov (United States)

Noury, Mélanie; Bernet, Matthias; Sempéré, Thierry

2014-05-01

The overthickened crust of the current Central Andes is commonly viewed as the result of tectonic shortening. However, in the present-day terrestrial forearc and arc of southwesternmost Peru, crustal thickness increases from 30 km along the coastline to >60 km below the active arc, whereas the upper crust exhibits little to no evidence of crustal shortening and, in constrast, many extensional features. How (and when) crustal overthickness was acquired in this region is thus little understood. Because crustal overthickening often results in extensional collapse and/or significant erosion, here we address this issue through a regional-scale study of exhumation using fission-track thermochronology. The limited fission-track data previously available in the area suggested that exhumation began during the Mesozoic. In this study, we present new apatite and zircon fission-track data obtained along the current terrestrial forearc of southwesternmost Peru. This relatively restricted area presents the interest of providing extensive outcrops of Precambrian to Ordovician basement and Early Jurassic to Late Cretaceous arc plutons. In order to compare the chronology of exhumation of these units, we performed extensive sampling for fission-track dating, as well as structural mapping. Our results indicate that the basement rocks and Jurassic plutons that crop out in the Arequipa region, where the crust is now >50 km-thick, experienced a rapid cooling through the 240-110°C temperature range between ~65 and ~35 Ma. This period of rapid exhumation coincided in time with the accumulation of terrestrial forearc deposits (the Lower Moquegua Group), that exhibit many syn-sedimentary extensional features and are bounded by conspicuous normal faults, specifically along the region where intense activity of the main arc between ~90 and ~60 Ma had led to voluminous magma emplacement. This close succession of (1) intense magmatic activity and (2) regional-scale exhumation associated with

A paleolimnological perspective on industrial-era metal pollution in the central Andes, Peru

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Cooke, Colin A. [Department of Geology, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, T6G 2E3 (Canada)], E-mail: cacooke@ualberta.ca; Abbott, Mark B. [Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, T6G 2E3 (Canada); Section of Anthropology, Carnegie Museum of Natural History, Pittsburgh, PA 15206 (United States)

2008-04-15

To date, few studies have investigated the environmental legacy associated with industrialization in the South American Andes. Here, we present an environmental archive of industrial pollution from {sup 210}Pb-dated lake cores recovered from Laguna Chipian, located near the Cerro de Pasco metallurgical region and Laguna Pirhuacocha, located near the Morococha mining region and the La Oroya smelting complex. At Laguna Chipian, trace metal concentrations increase beginning {approx} 1900 AD, coincident with the construction of the central Peruvian railway, and the rapid industrial development of the Cerro de Pasco region. Trace metal concentrations and fluxes peak during the 1950s before subsequently declining up-core (though remaining well above background levels). While Colonial mining and smelting operations are known to have occurred at Cerro de Pasco since at least 1630 AD, our sediment record preserves no associated metal deposition. Based on our {sup 14}C and {sup 210}Pb data, we suggest that this is due to a depositional hiatus, rather than a lack of regional Colonial pollution. At Laguna Pirhuacocha, industrial trace metal deposition first begins {approx} 1925 AD, rapidly increasing after {approx} 1950 AD and peaking during either the 1970s or 1990s. Trace metal concentrations from these lakes are comparable to some of the most polluted lakes in North America and Europe. There appears to be little diagenetic alteration of the trace metal record at either lake, the exception being arsenic (As) accumulation at Laguna Pirhuacocha. There, a correlation between As and the redox-sensitive element manganese (Mn) suggests that the sedimentary As burden is undergoing diagenetic migration towards the sediment-water interface. This mobility has contributed to surface sediment As concentrations in excess of 1100 {mu}g g{sup -1}. The results presented here chronicle a rapidly changing Andean environment, and highlight a need for future research in the rate and magnitude

An InSAR-based survey of volcanic deformation in the central Andes

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Pritchard, M. E.; Simons, M.

2004-02-01

We extend an earlier interferometric synthetic aperture radar (InSAR) survey covering about 900 remote volcanos of the central Andes (14°-27°S) between the years 1992 and 2002. Our survey reveals broad (10s of km), roughly axisymmetric deformation at 4 volcanic centers: two stratovolcanoes are inflating (Uturuncu, Bolivia, and Hualca Hualca, Peru); another source of inflation on the border between Chile and Argentina is not obviously associated with a volcanic edifice (here called Lazufre); and a caldera (Cerro Blanco, also called Robledo) in northwest Argentina is subsiding. We explore the range of source depths and volumes allowed by our observations, using spherical, ellipsoidal and crack-like source geometries. We further examine the effects of local topography upon the deformation field and invert for a spherical point-source in both elastic half-space and layered-space crustal models. We use a global search algorithm, with gradient search methods used to further constrain best-fitting models. Inferred source depths are model-dependent, with differences in the assumed source geometry generating a larger range of accepted depths than variations in elastic structure. Source depths relative to sea level are: 8-18 km at Hualca Hualca; 12-25 km for Uturuncu; 5-13 km for Lazufre, and 5-10 km at Cerro Blanco. Deformation at all four volcanoes seems to be time-dependent, and only Uturuncu and Cerro Blanco were deforming during the entire time period of observation. Inflation at Hualca Hualca stopped in 1997, perhaps related to a large eruption of nearby Sabancaya volcano in May 1997, although there is no obvious relation between the rate of deformation and the eruptions of Sabancaya. We do not observe any deformation associated with eruptions of Lascar, Chile, at 16 other volcanoes that had recent small eruptions or fumarolic activity, or associated with a short-lived thermal anomaly at Chiliques volcano. We posit a hydrothermal system at Cerro Blanco to explain the

Disappearance of the glacier on Mama Cotacachi: ethnoecological research and climate change in the Ecuadorian Andes

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Rhoades, R.

2008-12-01

Full Text Available A first documented case study of a disappearing glacier in the snow capped volcano Cotacahi in Ecuador is presented with the studies belonging to the social sciences in relation to climate change and its impact on the population of the Equatorial Andes. With the use of multiple source methodology, including ethnographic analyzes, visual representations, repetitive photography, critical mapping by the local communities, longitudinal surveys, even archival research, as well as interviews to social actors and utilization of spatial data in a geographical information system (GIS. It is concluded that the documented disappearance of the glacier on the Cotacahi serves as an urgent call for action to the important dearth of social research related to global change from the ethnoecological perspective, with a cultural, local approach.

Se presenta el primer estudio documentado de la desaparición del glaciar del nevado Cotacachi en el Ecuador, con los estudios que corresponden a las ciencias sociales en relación con el cambio climático y su impacto en la población de los Andes ecuatoriales. Mediante el uso de una metodología que incluye análisis etnográficos, representaciones visuales, fotografía repetitiva, mapeo crítico por parte de las comunidades locales, encuestas longitudinales e incluso investigación de archivos, así como también entrevistas a actores sociales, y utilización de los datos espaciales en un sistema de información geográfica (SIG. Se concluye que la desaparición documentada del glaciar del Cotacachi sirve como una llamada de atención urgente a la importante falta de investigaciones sociales relacionadas con el cambio global desde el punto de vista etnoecológico, con un enfoque cultural local.

Mesozoic–Cenozoic Evolution of the Western Margin of South America: Case Study of the Peruvian Andes

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Laura Gonzalez

2013-06-01

Full Text Available Based on the structural style and physiographic criteria, the Central Andes of Peru can be divided into segments running parallel to the Pacific coast. The westernmost segment, the Coastal Belt, consists of a Late Jurassic–Cretaceous volcanic arc sequence that was accreted to the South American craton in Cretaceous times. The Mesozoic strata of the adjacent Western Cordillera represent an ENE-vergent fold-and-thrust belt that formed in Eocene times. Tight upright folds developed above a shallow detachment horizon in the West, while more open folds formed above a deeper detachment horizon towards the East and in the neighboring Central Highlands. A completely different style with steeply dipping reverse faults and open folds affecting the Neoproterozoic crystalline basement is typical for the Eastern Cordillera. The Subandean Zone is characterized by mainly NE-vergent imbricate thrusting which occurred in Neogene times. A quantitative estimate of the shortening of the orogen obtained from balanced cross-sections indicates a total shortening of 120–150 km (24%–27%. This shortening was coevel with the Neogene westward drift of South America, occurred at rates between 3 and 4.7 mm/year and was responsible for the high elevation of the Peruvian Andes.

Genetic structure of Quechua-speakers of the Central Andes and geographic patterns of gene frequencies in South Amerindian populations.

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Luiselli, D; Simoni, L; Tarazona-Santos, E; Pastor, S; Pettener, D

2000-09-01

A sample of 141 Quechua-speaking individuals of the population of Tayacaja, in the Peruvian Central Andes, was typed for the following 16 genetic systems: ABO, Rh, MNSs, P, Duffy, AcP1, EsD, GLOI, PGM1, AK, 6-PGD, Hp, Gc, Pi, C3, and Bf. The genetic structure of the population was analyzed in relation to the allele frequencies available for other South Amerindian populations, using a combination of multivariate and multivariable techniques. Spatial autocorrelation analysis was performed independently for 13 alleles to identify patterns of gene flow in South America as a whole and in more specific geographic regions. We found a longitudinal cline for the AcP1*a and EsD*1 alleles which we interpreted as the result of an ancient longitudinal expansion of a putative ancestral population of modern Amerindians. Monmonnier's algorithm, used to identify areas of sharp genetic discontinuity, suggested a clear east-west differentiation of native South American populations, which was confirmed by analysis of the distribution of genetic distances. We suggest that this pattern of genetic structures is the consequence of the independent peopling of western and eastern South America or to low levels of gene flow between these regions, related to different environmental and demographic histories. Copyright 2000 Wiley-Liss, Inc.

Natural dam failure in the eastern slope of the Central Andes of Argentina. Numerical modelling of the 2005 Santa Cruz river outburst flood

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Penna, I.; Daicz, S.; Zlotnik, S.; Derron, M.-H.; Jaboyedoff, M.

2012-04-01

In the Central Andes of Argentina, ephemeral river blockage due to landslides deposition are common phenomena. During the first fortnight of January 2005, 11.5 * 106m3 of rock collapsed from the east slope of the Santa Cruz valley (San Juan province, Argentina). The rock mass displaced from 4300 m a.s.l., down to the valley bottom, at 2900 m a.s.l., and ran up the opposite flank of the valley. This produced the blockage of the Santa Cruz river and generated the Los Erizos lake. The rapid snow melting during the spring season caused the increase of the water level of the reservoir, leading to a process of overtopping on November 12th of 2005. 30 * 106m3 of water were released from the reservoir and the consequent outburst flood displaced along 250 km. From local reports of arrival times, we estimated that the outburst flood reduced its velocity from around 40 km/h near the source area to 6 km/h in its distal section. A road, bridges, and a mining post where destroyed. 75 tourists had to be rescued from the mountains using helicopters, and people from two localities had to be evacuated. Near its distal part, the flood damaged the facilities of the Caracoles power dam, which was under construction, and its inauguration had to be delayed one year due to the damage. The outburst flood produced changes in the morphology of the valley floor along almost all its path (erosion of alluvial fans, talus and terraces, and deposition of boulders). The most significant changes occurred in the first 70 km, especially upstream narrow sections, showing the importance of the backwater effects due to hydraulic ponding. In this work we carried out numerical simulations to obtain the velocity patterns of the flood, and compared them with those obtained from local reports. Furthermore, we analyze the relationship between the dynamics of the flood with the patterns of erosion and deposition near the source area.

The effect of highly variable topography on the spatial distribution of Aniba perutilis (Lauraceae in the Colombian Andes

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José C. Fagua

2013-03-01

Full Text Available Topography is a factor that can significantly affect the diversity and the distribution of trees species in tropical forests. Aniba perutilis, a timber species listed as vulnerable to extinction, is widely distributed in Andean forest fragments, especially in those with highly variable topography. Based on field surveys and logistic regression analyses, we studied the population structure and the effect of highly variable topography on the spatial distribution of this tree in three protected forest fragments in the central Andes of Colombia. Individuals of A. perutilis were mainly found on mountain ridges and hills with gentle slopes; no individuals were found in valleys. Using a species distribution model with presence/absence data, we showed that the available habitat for A. perutilis is significantly smaller than the extension of the fragments and much smaller than the extension of the currently protected areas. Our results have important implications for the conservation of A. perutilis and likely for other threatened Andean tree species, which can also have locally restricted distributions due to highly variable local topography.La topografía es un factor que puede afectar considerablemente la diversidad y la distribución de las especies de árboles tropicales. Aniba perutilis, una especie de árbol maderable vulnerable a la extinción, está ampliamente distribuida en fragmentos de bosques andinos, especialmente en aquellos con topografía altamente variable. A partir de trabajo de campo y análisis de regresión logística, estudiamos la estructura de la población y los efectos de la topografía sobre la distribución espacial de este árbol en tres fragmentos de bosque en la cordillera central de Colombia que actualmente se encuentran protegidos. Los individuos de A. perutilis se encontraron principalmente en los filos de montaña y colinas con gradientes topográficos suaves; no se encontraron individuos en los valles. A partir de un

Complicaciones mecánicas de los accesos venosos centrales

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Rodrigo Rivas, T.

2011-01-01

Las complicaciones mecánicas de los accesos venosos centrales son frecuentes, 2 a 15% y en ocasiones pueden comprometer la vida del paciente. Hay factores que determinan el riesgo de una u otra, que pueden ser modificados o enfrentados de diferente forma para minimizarlo. En esta puesta al día se describen las complicaciones más frecuentes o de mayor gravedad como son: el neumotórax, la embolia aérea, mal-posición del catéter, perforación de grandes venas, punción arterial, arritmias, trom...

INSATISFACCIÓN POR LA IMAGEN CORPORAL Y LA BAJA AUTOESTIMA POR LA APARIENCIA FÍSICA EN ESTUDIANTES DE LA FACULTAD DE MEDICINA DE LA UNIVERSIDAD DE LOS ANDES DEL ESTADO MERIDA VENEZUELA

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Pedro López Atencio

2008-07-01

Full Text Available La presente investigación tuvo como propósito central evaluar la insatisfacción por la imagen corporal y su relación con la baja autoestima por la apariencia física en estudiantes de la Facultad de Medicina de la Universidad de Los Andes en Mérida Venezuela. El estudio fue de tipo no experimental correlacional. La muestra estuvo constituida por 189 estudiantes, 27% masculino y 73% femenino, con una edad promedio de 19,58 años ± 1,57 (varones 19,81 años ± 1,74 y para las mujeres 20,24 años ± 1,76. Los participantes fueron seleccionados de los cursos del primer año de las carreras de: medicina, enfermería y nutrición, los cuales fueron seleccionados de forma intencional. El instrumento empleado para determinar la Insatisfacción por la Imagen Corporal fue el Body Shape Questionnaire (Cooper y Taylor, 1987. El método de Graffar Modificado fue utilizado para determinar el estrato socioeconómico de los participantes (Méndez y De Méndez, 1994. A los datos se les aplicó el análisis descriptivo (frecuencia, porcentajes, media e inferencial (ANOVA de un solo factor a través del paquete estadístico SPSS versión 9.0. Entre los principales hallazgos en el estudio se pudo determinar una asociación estadísticamente significativa entre la insatisfacción con la imagen corporal, la baja autoestima por la apariencia física con el género χ2 (2, N= 189 = 9,686, p=0,008. A través de ANOVA se pudo determinar que las diferencias en las medias para los niveles de insatisfacción y baja autoestima con la imagen corporal y el género son estadísticamente significativas, F=11,236; p=0,008, F=10,23; p=0,002 respectivamente. Conclusiones: los resultados obtenidos permiten sugerir sobre la relación que existe entre la insatisfacción y la baja autoestima por la apariencia física, existiendo un rechazo por la propia imagen corporal causada por la percepción distorsionada o no de la misma, lo que podría afectar la autoestima por la

Diversification of clearwing butterflies with the rise of the Andes.

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De-Silva, Donna Lisa; Elias, Marianne; Willmott, Keith; Mallet, James; Day, Julia J

2016-01-01

Despite the greatest butterfly diversity on Earth occurring in the Neotropical Andes and Amazonia, there is still keen debate about the origins of this exceptional biota. A densely sampled calibrated phylogeny for a widespread butterfly subtribe, Oleriina (Nymphalidae: Ithomiini) was used to estimate the origin, colonization history and diversification of this species-rich group. Neotropics. Ancestral elevation and biogeographical ranges were reconstructed using data generated from detailed range maps and applying the dispersal-extinction-cladogenesis model using stratified palaeogeographical time slice matrices. The pattern of diversification through time was examined by comparing constant and variable rate models. We also tested the hypothesis that a change in elevation is associated with speciation. The Oleriina likely originated in the Andes in the Early to Middle Miocene and rapidly diversified to include four genera all of which also originated in the Andes. These clades, together with four species groups, experienced varying spatial and temporal patterns of diversification. An overall early burst and decreasing diversification rate is identified, and this pattern is reflected for most subclades. Changes in the palaeogeological landscape, particularly the prolonged uplift of the Andes, had a profound impact on the diversification of the subtribe. The Oleriina mostly remained within the Andes and vicariant speciation resulted in some instances. Dynamic dispersal occurred with the disappearance of geological barriers such as the Acre System and the subtribe exploited newly available habitats. Our results confirm the role of the Andean uplift in the evolution of Neotropical biodiversity.

Los coquitos (chrysomelidae) de los pastos en los andes venezolanos "coquito pulga de los pastos" chaetocnema sp.

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Briceño Vergara, Armando J.

2007-01-01

Editorial. Suniaga Q., José La codorniz fuente proteica para consumo humano. Díaz Cuellar, Doraida R. y González, Diomary Diagnóstico de parásitos gastrointestinales en bovinos y su importancia en la productividad de los sistemas ganaderos. Castillo O., Mayela; Hernández, Javier A.; Betancourt, Arquímedes y Suniaga Q., José Nutrición vegetal (II). Moyeja Santana, Juan de Jesús Nutrición vegetal (III). Moyeja Santana, Juan de Jesús Plagas chupadoras de las cítrica...

Los palacios en la Costa Central durante los periodos Tardíos: de Pachacamac al Inca

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2004-01-01

Full Text Available LES PALAIS DE LA COTE CENTRALE DURANT LES PERIODES RECENTES : DE PACHACAMAC A L’INCA. Des études récentes portant sur la côte centrale du Pérou ont mis en évidence le fait que durant la période Intermédiaire récent (XIe au XVe s. dne l’architecture reliée au pouvoir était étroitement liée à un type particulier d’édifice : la résidence d’élite ou palais. Les données indiquent également que durant l’occupation inca dans la même région (15-16e siècles, ce type de bâtiment conserve toute son importance en tant que symbole spécifique du pouvoir politique des élites gouvernantes (c'est-à-dire les curacas. La persistance des palais de tradition locale comme référents de l’organisation politique de ce que l’on appelle la province inca de Pachacamac - tout du moins dans la zone correspondant au fleuve Rimac - met en evidence un thème toujours d’actualité dans le débat archéologique : quelles furent les caractéristiques du contrôle politique résultant de l’occupation inca dans cette partie du Tahuantinsuyu ? Quelle fut la reaction des élites locales face à l’ordre nouveau issu de la conquête ? Cet article développe ce thème à partir de la définition des attributs formels des palais, la description et l’usage des artefacts associés à ceux-ci, ainsi que l’analyse des sources historiques qui rendent compte des caractéristiques particulières de la société préhispanique récente de la côte centrale. Recientes estudios para la costa central del Perú han evidenciado que durante el periodo Intermedio Tardío (S. XI a XV d.C. la arquitectura del poder estuvo íntimamente ligada a un tipo particular de edificio: la residencia de elite o palacio. Las evidencias también indican que luego de la ocupación Inca de la misma región (S. XV, esta variedad de edificio conservó su vigencia como símbolo distintivo del poder político de las elites gobernantes (v.g. curacas. La persistencia de los palacios de

Participación de los estudiantes en el gobierno escolar Liceo Los Andes, Buga, 2014-2015

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Viáfara Zapata, María Yenny; Solarte Bastidas, Mario Fernando

2015-01-01

La presente investigación se justifica por cuanto creemos que el Gobierno Escolar facilita y promueve el desarrollo de Competencias Ciudadanas en los estudiantes, competencias encaminadas a formar ciudadanos con valores y capaces de ejercer sus derechos y cumplir con sus obligaciones. De otra parte, porque si bien las I.E. están avocadas a cumplir la ley en especial el Gobierno Escolar provoca el desarrollo de acciones para su organización e impulsa la participación de los estu...

Sr and Nd isotopic and trace element compositions of Quaternary volcanic centers of the Southern Andes

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Futa, K.; Stern, C.R.

1988-01-01

Isotopic compositions of samples from six Quaternary volcanoes located in the northern and southern extremities of the Southern Volcanic Zone (SVZ, 33-46??S) of the Andes and from four centers in the Austral Volcanic Zone (AVZ, 49-54??S) range for 87Sr 86Sr from 0.70280 to 0.70591 and for 143Nd 144Nd from 0.51314 to 0.51255. The ranges are significantly greater than previously reported from the southern Andes but are different from the isotopic compositions of volcanoes in the central and northern Andes. Basalts and basaltic andesites from three centers just north of the Chile Rise-Trench triple junction have 87Sr 86Sr, 143Nd 144Nd, La Yb, Ba La, and Hf Lu that lie within the relatively restricted ranges of the basic magmas erupted from the volcanic centers as far north as 35??S in the SVZ of the Andes. The trace element and Sr and Nd isotopic characteristics of these magmas may be explained by source region contamination of subarc asthenosphere, with contaminants derived from subducted pelagic sediments and seawater-altered basalts by dehydration of subducted oceanic lithosphere. In the northern extremity of the SVZ between 33?? and 34??S, basaltic andesites and andesites have higher 87Sr 86Sr, Rb Cs, and Hf Lu, and lower 143Nd 144Nd than basalts and basaltic andesites erupted farther south in the SVZ, which suggests involvement of components derived from the continental crust. In the AVZ, the most primitive sample, high-Mg andesite from the southernmost volcanic center in the Andes (54??S) has Sr and Nd isotopic compositions and K Rb and Ba La similar to MORB. The high La Yb of this sample suggests formation by small degrees of partial melting of subducted MORB with garnet as a residue. Samples from centers farther north in the AVZ show a regionally regular northward increase in SiO2, K2O, Rb, Ba, Ba La, and 87Sr 86Sr and decrease in MgO, Sr, K Rb, Rb Cs, and 143Nd 144Nd, suggesting increasingly greater degrees of fractional crystallization and associated intra

A new species of Telmatobius (Amphibia, Anura, Telmatobiidae from the Pacific slopes of the Andes, Peru

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Alessandro Catenazzi

2015-02-01

Full Text Available We describe a new species of Telmatobius from the Pacific slopes of the Andes in central Peru. Specimens were collected at 3900 m elevation near Huaytará, Huancavelica, in the upper drainage of the Pisco river. The new species has a snout–vent length of 52.5 ± 1.1 mm (49.3–55.7 mm, n = 6 in adult females, and 48.5 mm in the single adult male. The new species has bright yellow and orange coloration ventrally and is readily distinguished from all other central Peruvian Andean species of Telmatobius but T. intermedius by having vomerine teeth but lacking premaxillary and maxillary teeth, and by its slender body shape and long legs. The new species differs from T. intermedius by its larger size, flatter head, and the absence of cutaneous keratinized spicules (present even in immature females of T. intermedius, and in males by the presence of minute, densely packed nuptial spines on dorsal and medial surfaces of thumbs (large, sparsely packed nuptial spines in T. intermedius. The hyper-arid coastal valleys of Peru generally support low species richness, particularly for groups such as aquatic breeding amphibians. The discovery of a new species in this environment, and along a major highway crossing the Andes, shows that much remains to be done to document amphibian diversity in Peru.

Características de uso de plaguicidas químicos y riesgos para la salud en agricultores de la sierra central del Perú

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Ymelda Montoro

2009-10-01

Full Text Available Con el objetivo de conocer las características sobre el uso e impactos en la salud de los plaguicidas químicos de uso agrícola en las provincias de Chupaca y Concepción en los andes centrales del Perú, se desarrolló un estudio descriptivo transversal entre abril y junio del año 2005, por medio de un cuestionario aplicado a 435 agricultores. Asimismo, se exploró la ubicación de los centros de expendio y la frecuencia de ventas de productos, además, se evaluó los casos de intoxicación reportados en ambas provincias. Los agricultores no cuentan con ropa de protección y manipulan directamente los plaguicidas durante su preparación y aplicación; asimismo, muchas veces no toman medidas preventivas a pesar de conocer los riesgos relacionados. El comercio de los plaguicidas se ubica en los centros urbanos, cerca de restaurantes y tiendas de abarrotes, además, los plaguicidas más vendidos pertenecen a las categorías extremadamente y altamente peligrosos, tales como Tamaron® y Furadan®, esto representa un peligro para la salud de los agricultores. Los casos de intoxicación por estos productos en las provincias bajo estudio, se han incrementado entre los años 2001 a 2004.

Ontogenia de los estróbilos, desarrollo de los esporangios y esporogénesis de Equisetum giganteum (Equisetaceae en los Andes de Colombia

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Edgar Javier Rincón Barón

2011-12-01

Full Text Available Estudios sobre la ontogenia del estróbilo, los esporangios y la biología reproductiva de Equisetum son escasos, por lo tanto, para la especie E. giganteum, se estudiaron estos aspectos en especímenes recolectados a orillas del Río Frío, Santander, Colombia (2 200m. Los estróbilos en diferentes etapas de maduración fueron fijados, deshidratados, embebidos en parafina, seccionados en micrótomo rotatorio y teñidos con safranina O-fast green. Las observaciones se efectuaron mediante un microscopio óptico de alta resolución con contraste diferencial de interferencia (DIC y microscopio de fluorescencia. Los estróbilos se inician a partir del meristemo apical, tanto en el eje principal como en los laterales, sin diferencias en el proceso de ontogenia y esporogénesis entre estróbilos de diferentes ejes. Sucesivas mitosis y diferenciación celular conducen al crecimiento del estróbilo, y a la formación de los esporangióforos peltados, formados por el manubrio, o porción basal con aspecto de pedicelo, el escutelo, o porción apical aplanada y las iniciales del esporangio, los cuales se diferenciarán para formar la pared del esporangio, los esporocitos y el tapete. No se forma arquesporio y los esporocitos experimentan meiosis para formar tétradas de esporas. El tapete mantiene la integridad histológica hasta la formación de las tétradas y en esa etapa forma un plasmodio que invade la cavidad esporangial la cual rodea parcialmente las tétradas y luego las esporas, y aparecen las cámaras plasmodiales, un término propuesto aquí para las formaciones designadas en inglés "tapetal gaps". La pared del esporangio queda reducida a dos capas celulares: una externa con engrosamientos lignificados en todas las paredes celulares y una interna picnótica. Al finalizar la esporogénesis, el tapete degenera, y las esporas, con exosporio, perisporio delgado, casi membranáceo y eláteres quedan libres en la cavidad esporangial. El esporodermo

Litterfall production under pine plantations in the southern Andes region of Ecuador

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Pablo Quichimbo

2016-09-01

Full Text Available Litterfall research is an interesting aspect in environmental studies due to its significance in nutrient cycling specially in regions like the Andes where the interactions between biomass production and its decomposition is poorly understood. This study is focusing in the litterfall biomass production under pine plantations in southern Ecuador. The litterfall production was studied for five months at two-week intervals in three pine forest sites located in the southern Andes region of Ecuador. Monthly litterfall production ranged between 1067-1907 kg ha-1, in comparison with other coniferous stands around the world, this study revealed a higher litterfall production for tropical areas and particularly the highest production under pine plantations in the Andes region. This high litterfall production highlights the upmost importance of this forest component as a potential nutrient reservoir involved in the global nutrient cycling under landscapes dominated by this exotic forest specie in the tropical Andes.

Influencia del fenómeno ENSO sobre la precipitación nival en el sector andino de Chile central durante el invierno

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1998-01-01

Full Text Available INFLUENCE DU PHÉNOMÈNE ENSO SUR LES PRÉCIPITATIONS NEIGEUSES DANS LE CENTRE DU CHILI ANDIN AU COURS DE L’HIVER AUSTRAL. On analyse l’influence du phénomène El Niño/Oscillation du Sud (ENSO sur les précipitations nivales dans les Andes du Chili central au cours de l’hiver. Pour cela, on a utilisé l’information obtenue sur des sites spécifiques (routes de neige situées entre 30° et 38° S et les anomalies de Température de Surface de la Mer (TSM du bloc Niño 3, comme indicateur de l’importance des événements chauds ou froids dans le Pacifique équatorial central. Au nord de 35°S, l’accumulation de neige tend à être supérieure à la normale quand l’anomalie moyenne de TSM dépasse +1°C au cours de la période mai-août. Dans ce même secteur, on enregistre une précipitation inférieure à la normale les hivers caractérisés par une anomalie de TSM inférieure à -0,5°C. Dans la zone située au sud de 35° S, l’influence du phénomène ENSO sur l’accumulation de neige n’est plus significative. Se analiza la influencia del fenómeno El Niño/Oscilación del Sur (ENSO sobre la precipitación nival en los Andes de Chile central durante el invierno. Para esto, se utiliza información de rutas de nieve localizadas entre 30° y 38° S, y de anomalías de temperatura superficial del mar (TSM en la región Niño 3 como un indicador de la magnitud de los eventos cálidos y fríos en el Pacífico ecuatorial central. En la región al norte de 35° S, la acumulación de nieve durante el invierno tiende a ser superior a lo normal cuando la magnitud de la anomalía media de TSM en el periodo mayo-agosto supera +1,0° C. En este mismo sector se verifica que durante los inviernos caracterizados por una anomalía de TSM inferior a -0,5° C, suele registrarse una precipitación nival inferior a lo normal. En el sector al sur de los 35° S, la influencia del fenómeno ENSO sobre la acumulación de nieve durante el invierno no es

Análisis de los ácidos kaurénicos presentes en Espeletiopsis angustifolia Cuatrec. de los Andes venezolanos

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Juan Carmona

2010-05-01

Full Text Available Analysis of kaurenic acids present in Espeletiopsis angustifolia Cuatrec. from the Venezuelan Andes. Leaves of Espeletiopsis angustifolia were collected at paramo of San José de Acequias (Mérida State at 2870 m.a.s.l. The dried leaves were minced and extracted with hexane-diethyl ether (3:1. This extract was shaken with 0.5 N NaOH to separate the acid fraction which was purified by flash chromatography. An aliquote of it was methylated with diazomethane and analyzed by GC-MS which permitted to identify ent-kaurenic acid (18.6%, ent-15α-O-isovaleroxy-kaur-16-en-19-oic acid (16.2%, ent-15α-hidroxy-kaur-16-en-19-oic acid (grandiflorolic acid, 9.2%, ent-kauranic acid (4.9%, ent-kaur-9(11,16-diene-19-oic acid (grandiflorenic acid, 4.5% and ent-15α-O-acetoxy-kaur-16-en-19-oic acid (3.4%. The neutral fraction yielded ent-kaur-16-en-19-ol (kaurenol, 32.7% and several long-chain wax n-alkanes with predominance of odd carbon number alkanes: heptacosane (38.3%, nonacosane (21.0% and entriacontane (4.6%

Charles Darwin in the Andes

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Bizzo, Nelio; Bizzo, Luis Eduardo Maestrelli

2006-01-01

Considering geological time as an important epistemological obstacle to the construction of ideas on biological evolution, a study was carried out on the so-called "Darwin Papers". The conclusion was that Charles Darwin's excursion in the Andes during March-April 1835 was a crucial step in this regard. An expedition was carried out in…

Influence of inherited structures on the growth of basement-cored ranges, basin inversion and foreland basin development in the Central Andes, from apatite fission-track and apatite Helium thermochronology.

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Zapata, S.; Sobel, E. R.; Del Papa, C.; Jelinek, A. R.; Muruaga, C.

2017-12-01

The Central Andes in NW of Argentina is part of a long-lived subduction zone, active since the Paleozoic. This region experienced several tectonic cycles; each of which created an unique set of structures and may have reactivated preexisting structures. These inherited structures may exert a first-order control over the different foreland deformational styles observed along the strike in the Central Andes. Our study area is located between 26°S and 28°S on the transition between the broken foreland (Santa Barbara system), which expresses a combination of thin-skin and thick-skin styles, and the Sierras Pampeanas, which is deform in a thick-skin style. The Cumbres Calchaquies range and the associated Choromoro Basin are located in the northern part of the study area, and are the southern expression of the Santa Barbara system. Published thermochronology data suggest that the rocks from the basement experienced Late Cretaceous and Late Miocene exhumation; the associated sedimentary rocks within the Choromoro basin experienced Paleogene and Late Miocene deformational phases. In contrast, the Sierra Aconquija range, located immediately south on the transition to the Sierras Pampeanas (thick skin) foreland basin, exhibit larger amounts of Miocene exhumation and lack of Cretaceous exhumation; the associated sedimentary rocks from the Tucuman basin have not been deformed since the Cretaceous. Our goal is to understand the evolution of the structural blocks and the structures responsible for the along strike changes in foreland basin deformational styles and their relation with inherited structures from previous tectonic cycles. We are obtaining new apatite U-Th/He and fission track data to reconstruct the thermal history of the basement, accompanied by U-Pb geochronology and stratigraphy to constrain the evolution of the associated sedimentary basins. Preliminary results combined with published data suggest that inherited structures within the study area have evolved

Is tourism damaging ecosystems in the Andes? Current knowledge and an agenda for future research.

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Barros, Agustina; Monz, Christopher; Pickering, Catherine

2015-03-01

Despite the popularity of tourism and recreation in the Andes in South America and the regions conservation value, there is limited research on the ecological impacts of these types of anthropogenic use. Using a systematic quantitative literature review method, we found 47 recreation ecology studies from the Andes, 25 of which used an experimental design. Most of these were from the Southern Andes in Argentina (13 studies) or Chile (eight studies) with only four studies from the Northern Andes. These studies documented a range of impacts on vegetation, birds and mammals; including changes in plant species richness, composition and vegetation cover and the tolerance of wildlife of visitor use. There was little research on the impacts of visitors on soils and aquatic systems and for some ecoregions in the Andes. We identify research priorities across the region that will enhance management strategies to minimise visitor impacts in Andean ecosystems.

Geology, petrology and geochemistry of the dome complex of Huequi volcano, southern Chile Geología, petrología y geoquímica de los domos volcánicos del volcán Huequi, Chile meridional

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Sebastian F.L Watt

2011-07-01

Full Text Available Huequi, a little-known volcano in the southern part of the Andean southern volcanic zone (SSVZ, shows a regionally unusual eruption style, mineralogy and geochemistry. The volcano comprises multiple highly-eroded lava domes. Past eruptions were accompanied by relatively minor explosive activity, most recently from 1890-1920. The rocks erupted by Huequi range from basaltic andesite to dacite, and are highly distinctive when compared to other volcanoes of the SSVZ, being K-poor and Al-rich, and containing euhedral hornblende phenocrysts. Overall compositions suggest a notably water-rich magma source, evolving through high levels of fractionation and subsequent degassing to produce highly porphyritic dome-forming andesites. The ultimate causes of water-rich magmas at this point in the arc remain unclear.El volcán Huequi es poco conocido, que se ubica en la provincia sur de la zona Volcánica Sur de los Andes (ZVSS. Sus tipos de erupción y características mineralógicas y geoquímicas son poco comunes a nivel regional. El volcán presenta múltiples domos poco erosionados. Las erupciones estuvieron acompañadas por una actividad explosiva secundaria, siendo las más recientes las ocurridas entre los años 1890 y 1920. Los magmas del Huequi son de composición andesítico-basáltica a dacítica. Si se las compara con rocas eruptadas por otros centros volcánicos de la ZVSS de los Andes, las del Huequi se caracterizan por ser pobres en K, ricas en Al y por presentar fenocristales euhedrales de anfíbola. Las composiciones totales sugieren una fuente magmática rica en H2O, que se desarrolla a través de niveles de cristalización fraccionada y desgasificación subsecuente, que producen domos volcánicos andesíticos altamente porfíricos. Sin embargo, la causa última que genera magmas ricos en H2O, en esta parte de los Andes, sigue aún sin explicación.

Neogene paleoelevation of intermontane basins in a narrow, compressional mountain range, southern Central Andes of Argentina

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Hoke, Gregory D.; Giambiagi, Laura B.; Garzione, Carmala N.; Mahoney, J. Brian; Strecker, Manfred R.

2014-11-01

The topographic growth of mountain ranges at convergent margins results from the complex interaction between the motion of lithospheric plates, crustal shortening, rock uplift and exhumation. Constraints on the timing and magnitude of elevation change gleaned from isotopic archives preserved in sedimentary sequences provide insight into how these processes interact over different timescales to create topography and potentially decipher the impact of topography on atmospheric circulation and superposed exhumation. This study uses stable isotope data from pedogenic carbonates collected from seven different stratigraphic sections spanning different tectonic and topographic positions in the range today, to examine the middle to late Miocene history of elevation change in the central Andes thrust belt, which is located immediately to the south of the Altiplano-Puna Plateau, the world's second largest orogenic plateau. Paleoelevations are calculated using previously published local isotope-elevation gradients observed in modern rainfall and carbonate-formation temperatures determined from clumped isotope studies in modern soils. Calculated Neogene basin paleoelevations are between 1 km and 1.9 km for basins that today are located between 1500 and 3400 m elevation. Considering the modern elevation and δ18O values of precipitation at the sampling sites, three of the intermontane basins experienced surface uplift between the end of deposition during the late Miocene and present. The timing of elevation change cannot be linked to any documented episodes of large-magnitude crustal shortening. Paradoxically, the maximum inferred surface uplift in the core of the range is greatest where the crust is thinnest. The spatial pattern of surface uplift is best explained by eastward migration of a crustal root via ductile deformation in the lower crust and is not related to flat-slab subduction.

Effects of diet and water supply on energy intake and water loss in a mygalomorph spider in a fluctuating environment of the central Andes.

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Canals, M; Figueroa, D; Alfaro, C; Kawamoto, T; Torres-Contreras, H; Sabat, P; Veloso, C

2011-11-01

The metabolic and water evaporation strategies in spiders may be part of a set of physiological adaptations to tolerate low or unpredictable food availability, buffering spiders against environmental fluctuations such as those of the high mountains of the central Andes. The aim of this study is to analyze experimentally the variations in metabolic rate and the rate of evaporative water with food and/or water restriction in a high mountain mygalomorph spider population (Paraphysa sp.). We found that the low metabolism of this spider was not affected by water restriction, but its metabolism was depressed after 3 weeks of food deprivation. The spider did not show seasonal metabolic changes but it presented seasonal changes in the rate of evaporative water loss at high temperatures. Females with egg sacs reduced their metabolic rate and evaporative water at high temperatures. These findings constitute a set of possible adaptations to a highly fluctuating Mediterranean environment, which is completely covered with snow for many months and then progresses rapidly to a very dry climate with high temperatures. Copyright © 2011 Elsevier Ltd. All rights reserved.

Multiproxy Holocene paleoclimate records from the southern Peruvian Andes - what new can we learn from the stable carbon isotope composition of high altitude organic matter deposits?

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Skrzypek, Grzegorz; Engel, Zbyněk

2015-04-01

Interpretation of the Central Andean paleoclimate over the last millennia still represents a research challenge demanding deeper studies [1,2]. Several high-resolution paleoclimate proxies for the last 10,000 years have been developed for the northern hemisphere. However, similar proxies are very limited for South America, particularly for high altitudes where, for example, tree-ring chronologies are not available and instrumental records are very limited. Consequently, our knowledge of high altitude climate changes in arid regions of the Peruvian Andes mainly relies on ice-core and lake deposit studies. In our study, we used a new alternative proxy for interpretation of palaeoclimate conditions based on a peat core taken from the Carhuasanta Valley at the foot of Nevado Mismi in the southern Peruvian Andes (15° 30'S, 71° 43'W, 4809m a.s.l.). The stable carbon isotope composition (δ13C) of Distichia peat reflects mainly the relative variation of the mean air temperature during subsequent growing seasons [3], and allows reconstructions of palaeotemperature changes. In contrast, peat organic carbon concentration (C % wt) records mainly wetness in the valley, directly corresponding to the changes in runoff in the upper part of the catchment. The most prominent climate changes recorded in the peat over last 4ka occurred between 3040 and 2750 cal. yrs BP. The initial warming turned to a very rapid cooling to temperatures at least 2° C lower than the mean for the Late Holocene. Initially drier conditions within this event turned to a short wet phase after 2780 cal. yrs BP, when the temperature increased again. This event coincides with significant changes in peat and ice core records in the Central Andes that match the timing of the global climate event around 2.8 cal. ka BP. Climatic conditions in the study area became relatively dry and stable after the event for about 800 years. Highly variable temperatures and humidity prevailed during the last 2000 years, when

Distributional patterns of cecropia (Cecropiaceae: a panbiogeographic analysis

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Franco Rosselli Pilar

1997-06-01

Full Text Available A panbiogeographic analysis of the distributional patterns of 60 species of Cecropia was carried out. Based on the distributional ranges of 36 species, we found eight generalized tracks for Cecropia species. whereas distributional patterns of 24 species were uninformative for the analysis. The major concentration of species of Cecropia is in the Neotropical Andean region. where there are three generalized tracks and two nodes. The northern Andes in Colombia and Ecuador are richer than the Central Andes in Perú. they contain two generalized tracks; one to the west and another to the east, formed by individual tracks of eight species each. There are four generalized tracks outside the Andean region: two in the Amazonian region in Guayana-Pará and in Manaus. one in Roraima. one in Serra do Mar in the Atlantic forest of Brazil and one in Central America. Speciation in Cecropia may be related to the Andean first uplift.Con base en la distribución de 60 especies del género Cecropia, se hizo un análisis panbiogeográfico. Se construyeron 8 trazos generalizados con base en el patrón de distribución de 36 especies; la distribución de las demás especies no aportaba información para la definición de los trazos. La región andina tiene la mayor concentración de especies de Cecropia representada por la presencia de tres trazos generalizados y dos nodos; los dos trazos con mayor número de especies se localizan en su parte norte, en Colombia y Ecuador y el otro en los Andes centrales en Perú. Se encontraron además, cuatro trazos extrandinos: dos en la región amazónica, en Pará-Guayana y en Manaus, uno en Roraima, uno en Serra do Mar en la Selva Atlánfíca del Brasil y uno en Centro América. La especiación en Cecropia parece estar relacionada con el primer levantamiento de los Andes.

Surnames and genetic structure of a high-altitude Quechua community from the Ichu River Valley, Peruvian Central Andes, 1825-1914.

Science.gov (United States)

Pettener, D; Pastor, S; Tarazona-Santos, E

1998-10-01

Changes in isolation, inbreeding, population subdivision, and isonymous relationships are examined in six Quechua communities from the upper valley of the Ichu River in the Peruvian Central Andes (3700 m). All marriages registered between 1825 and 1914 in the Parish of Santa Ana were analyzed. The data (1680 marriages) were divided into 2 periods (1825-1870 and 1871-1914) and into the 6 villages that constitute the parish. Endogamy rates are between 81% and 100%, indicating high levels of reproductive isolation. The inbreeding indicated by isonymy (Ft, Fr, and Fn) is lower than in other mountain populations studied. Isonymy values, calculated from the different surname combinations made possible by the Ibero-American Surnames System, indicate a strong rejection of consanguineous marriages, particularly between patrilineal relatives, in agreement with the parental structure typical of Andean populations. The comparison between observed and expected repeated-pair values reveals a moderate level of subdivision within populations, which could be related to cultural and socioeconomic factors. Nonmetric multidimensional scaling was used to investigate temporal changes in the isonymous relationships among the communities. The results reveal a decrease in the interpopulational variability measured by surnames, in agreement with an increase in exogamy. Surnames and data contained in historical and demographic records yield reliable information, and they can be used to reconstruct the biological history of Amerindian populations over the last few centuries.

Preliminary Depositional and Provenance Records of Mesozoic Basin Evolution and Cenozoic Shortening in the High Andes, La Ramada Fold-Thrust Belt, Southern-Central Andes (32-33°S)

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Mackaman-Lofland, C.; Horton, B. K.; Fuentes, F.; Constenius, K. N.; McKenzie, R.; Alvarado, P. M.

2015-12-01

The Argentinian Andes define key examples of retroarc shortening and basin evolution above a zone of active subduction. The La Ramada fold-thrust belt (RFTB) in the High Andes provides insights into the relative influence and temporal records of diverse convergent margin processes (e.g. flat-slab subduction, convergent wedge dynamics, structural inversion). The RFTB contains Mesozoic extensional basin strata deformed by later Andean shortening. New detrital zircon U-Pb analyses of Mesozoic rift sediments reveal: (1) a dominant Permo-Triassic age signature (220-280 Ma) associated with proximal sources of effective basement (Choiyoi Group) during Triassic synrift deposition; (2) upsection younging of maximum depositional ages from Late Triassic through Early Cretaceous (230 to 100 Ma) with the increasing influence of western Andean arc sources; and (3) a significant Late Cretaceous influx of Paleozoic (~350-550 Ma) and Proterozoic (~650-1300 Ma) populations during the earliest shift from back-arc post-extensional subsidence to upper-plate shortening. The Cenozoic detrital record of the Manantiales foreland basin (between the Frontal Cordillera and Precordillera) records RFTB deformation prior to flat-slab subduction. A Permo-Triassic Choiyoi age signature dominates the Miocene succession, consistent with sources in the proximal Espinacito range. Subordinate Mesozoic (~80-250 Ma) to Proterozoic (~850-1800 Ma) U-Pb populations record exhumation of the Andean magmatic arc and recycling of different structural levels in the RFTB during thrusting/inversion of Mesozoic rift basin strata and subjacent Paleozoic units. Whereas maximum depositional ages of sampled Manantiales units cluster at 18-20 Ma, the Estancia Uspallata basin (~50 km to the south) shows consistent upsection younging of Cenozoic populations attributed to proximal volcanic centers. Ongoing work will apply low-temperature thermochronology to pinpoint basin accumulation histories and thrust timing.

SRTM Perspective of Colored Height and Shaded Relief Laguna Mellquina, Andes Mountains, Argentina

Science.gov (United States)

2001-01-01

This depiction of an area south of San Martin de Los Andes, Argentina, is the first Shuttle Radar Topography Mission (SRTM)view of the Andes Mountains, the tallest mountain chain in the western hemisphere. This particular site does not include the higher Andes peaks, but it does include steep-sided valleys and other distinctive landforms carved by Pleistocene glaciers. Elevations here range from about 700 to 2,440 meters (2,300 to 8,000 feet). This region is very active tectonically and volcanically, and the landforms provide a record of the changes that have occurred over many thousands of years. Large lakes fill the broad mountain valleys, and the spectacular scenery here makes this area a popular resort destination for Argentinians.Three visualization methods were combined to produce this image: shading, color coding of topographic height and a perspective view. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark, as would be the case at noon at this latitude in the southern hemisphere. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red, and magenta, to white at the highest elevations. The perspective is toward the west, 20 degrees off horizontal with 2X vertical exaggeration. The back (west) edge of the data set forms a false skyline within the Andes Range.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission aboard Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved

Clima Organizacional y el Desempeño Laboral de los trabajadores de la Gerencia Central de Logística de la Sede Central del Ministerio Público – 2014

OpenAIRE

Arévalo Contreras, Niltón César; Arroyo Muñoz, Carol Liliana

2016-01-01

La presente investigación tuvo como objetivo general de determinar qué relación existe entre el Clima Organizacional y el Desempeño Laboral de los trabajadores de la Gerencia Central de Logística de la Sede Central del Ministerio Público – 2014, la población fue Constituida por 265 trabajadores del Ministerio Público, como muestra no probabilística por conveniencia se consideró a 114 trabajadores de la población, en los cuales se han empleado la variable: Clima Organizacional ...

Diseño de la estrategia de Inglés con propósitos específicos en un contexto extracurricular para el aprendizaje del Inglés técnico médico en estudiantes de medicina de la Universidad Regional Autónoma de los Andes

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Montes De Oca Sánchez, Irma Verónica

2017-01-01

1. Introducción. 2. Planteamiento de la propuesta de trabajo 3. Marco Teórico 4. Metodología 5. Resultados 6. Conclusiones y Recomendaciones. En el proceso de formación profesional del médico que realiza sus estudios en la Universidad Regional Autónoma de los Andes, se incluye la preparación en el dominio de competencias en inglés; misma que comprende el aprendizaje del inglés con propósitos generales (EGP) y no abarca el aprendizaje de aspectos específicos relacionados ...

Fault-controlled development of shallow hydrothermal systems: Structural and mineralogical insights from the Southern Andes

Science.gov (United States)

Roquer, T.; Arancibia, G.; Rowland, J. V.; Iturrieta, P. C.; Morata, D.; Cembrano, J. M.

2017-12-01

Paleofluid-transporting systems can be recognized as meshes of fracture-filled veins in eroded zones of extinct hydrothermal systems. Here we conducted meso-microstructural analysis and mechanical modeling from two exhumed exposures of the faults governing regional tectonics of the Southern Andes: the Liquiñe-Ofqui Fault System (LOFS) and the Andean Transverse Faults (ATF). A total of 107 fractures in both exposures were analyzed. The ATF specific segment shows two tectonic solutions that can be modeled as Andersonian and non-Andersonian tectonic regimes: (1) shear (mode II/III) failure occurs at differential stresses > 28 MPa and fluid pressures 85-98% lithostatic in the non-Andersonian regime. Additionally, the LOFS exposure cyclically fails in extension (mode I) or extension + shear (modes I + II/III) in the Andersonian regime, at differential stresses 40-80% lithostatic. In areas of spatial interaction between ATF and LOFS, these conditions might favor: (1) the storage of overpressured fluids in hydrothermal systems associated with the ATF faults, and (2) continuous fluid flow through vertical conduits in the LOFS faults. These observations suggest that such intersections are highly probable locations for concentrated hydrothermal activity, which must be taken into consideration for further geothermal exploration. ACKNOWLEDGEMENTS. PhD CONICYT grants, Centro de Excelencia en Geotermia de los Andes (CEGA-FONDAP/CONICYT Project #15090013), FONDECYT Project #1130030 and Project CONICYT REDES #140036.

CARACTERIZACIÓN CLIMATICA DE LA ALTA CUENCA DEL RÍO NEUQUÉN, ANDES PATAGONICOS

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Griselda Ostertag

2005-12-01

Full Text Available En el desarrollo del presente documento se analizan las principales variables meteorológicas, temperatura y precipitación, que caracterizan y definen el clima de la Cordillera de los Andes en la Patagonia, provincia de Neuquén, particularmente en el área que ocupa la alta cuenca del río Neuquén. En esta etapa, de tipo descriptiva, el análisis estadístico refleja la situación de la climatología regional en el nivel medio histórico mediante la evaluación del comportamiento de las variables mencionadas durante los últimos 25 años. En este período se han registrado eventos extremadamente húmedos como así también situaciones de sequía. El objetivo es realizar una evaluación climática a partir de la información “in situ” de estaciones meteorológicas, información satelital y análisis estadístico para definir a posteriori, en cuál clasificación climática puede encuadrarse la zona de estudio, qué tipos climáticos pueden definirse en función de la bibliografía existente al respecto, y evaluar el grado de ajuste que presentan los climas determinados con los demás componentes del paisaje tales como vegetación y suelos.

Carbunco: una investigación clínica en los andes peruanos

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SALINAS, DAVID

2013-01-01

Objetivo: Describir las características clínicas del carbunco (ántrax) en los pacientes de una zona de altura peruana. Material y Métodos: Se captó veintinueve casos sospechosos de carbunco cutáneo, todos residentes de Santiago de Chocorvos. En once pacientes se realizó un estudio histopatológico de las lesiones cutáneas, en seis casos un estudio con coloración de Gram de frotises de lesiones cutáneas. Resultados: Todos los pacientes presentaron una infección limitada a nivel cutáneo. Las les...

Electric generator overhaul of the Ing. Carlos Ramirez Ulloa hydroelectric. Central project conclusions; Rehabilitacion de los generadores de la central hidroelectrica Ing. Carlos Ramirez Ulloa. Conclusiones del proyecto

Energy Technology Data Exchange (ETDEWEB)

Campuzano Martinez, Ignacio Roberto; Gonzalez Vazquez, Alejandro Esteban; Robles Pimentel, Edgar Guillermo; Esparza Saucedo, Marcos; Garcia Martinez, Javier; Sanchez Flores, Ernesto; Martinez Romero, Jose Luis [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1999-12-31

The Hydroelectric Ing. Carlos Ramirez Ulloa Power Central has three 200 MW electric generators. The Central initiated its commercial operation in 1985. The electric generators had design problems that were properly corrected in an overhaul program that was initiated in 1996, with Unit 2 electric generator and completed in 1998 with Unit 1 electric generator. This paper presents the relevant aspects of the experience accumulated in the project. [Espanol] La central hidroelectrica Ing. Carlos Ramirez Ulloa cuenta con tres generadores de 200 MW cada uno. La central inicio su operacion comercial en 1985. Los generadores tenian problemas de diseno que fueron debidamente corregidos en un programa de rehabilitacion que inicio en 1996, con el generador de la unidad 2, y culmino en 1998 con el generador de la unidad 1. En este articulo se presentan los aspectos relevantes de la experiencia acumulada en el proyecto.

Electric generator overhaul of the Ing. Carlos Ramirez Ulloa hydroelectric. Central project conclusions; Rehabilitacion de los generadores de la central hidroelectrica Ing. Carlos Ramirez Ulloa. Conclusiones del proyecto

Energy Technology Data Exchange (ETDEWEB)

Campuzano Martinez, Ignacio Roberto; Gonzalez Vazquez, Alejandro Esteban; Robles Pimentel, Edgar Guillermo; Esparza Saucedo, Marcos; Garcia Martinez, Javier; Sanchez Flores, Ernesto; Martinez Romero, Jose Luis [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1998-12-31

The Hydroelectric Ing. Carlos Ramirez Ulloa Power Central has three 200 MW electric generators. The Central initiated its commercial operation in 1985. The electric generators had design problems that were properly corrected in an overhaul program that was initiated in 1996, with Unit 2 electric generator and completed in 1998 with Unit 1 electric generator. This paper presents the relevant aspects of the experience accumulated in the project. [Espanol] La central hidroelectrica Ing. Carlos Ramirez Ulloa cuenta con tres generadores de 200 MW cada uno. La central inicio su operacion comercial en 1985. Los generadores tenian problemas de diseno que fueron debidamente corregidos en un programa de rehabilitacion que inicio en 1996, con el generador de la unidad 2, y culmino en 1998 con el generador de la unidad 1. En este articulo se presentan los aspectos relevantes de la experiencia acumulada en el proyecto.

Measurements in Los Alamos benchmark criticals and the central reactivity discrepancy

International Nuclear Information System (INIS)

Davey, W.G.; Hansen, G.E.; Koelling, J.J.; McLaughlin, T.P.

1978-01-01

Measurements in seven Los Alamos fast critical facilities are described; all are related to elucidating the causes of the central reactivity discrepancy in fast reactors. Specific capabilities of these specialized assemblies permit measurements well-above delayed critical and these confirm the validity of the delayed neutron data used for calibration; there is therefore no reactivity-scale error. Reactivity measurements in these homogeneous assemblies exhibit no discrepancy. It is concluded that nuclear data should not be adjusted to eliminate the discrepancy found in other, heterogeneous assemblies

Estudio florístico de los páramos de pajonal meridionales de Ecuador

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Jesús Izco

2013-04-01

Full Text Available El presente trabajo es un estudio de la flora de los páramos de pajonal seriales de distintos macizos montañosos de los Andes del Sur de Ecuador (provincias de Azuay y Loja comprendidos entre los 2850 m y 3635 m. Fueron identificadas 43 familias de plantas vasculares, 120 géneros y 216 especies. La flora local es comparada con la de otros páramos de pajonal andinos; la riqueza florística (géneros y especies es analizada por tramos altitudinales y se establece la flora característica de cada tramo del territorio estudiado. De forma complementaria, discutimos las influencias biogeográficas de la flora de los páramos de pajonal.

SRTM Colored Height and Shaded Relief: Laguna Mellquina, Andes Mountains, Argentina

Science.gov (United States)

2001-01-01

This depiction of an area south of San Martin de Los Andes, Argentina, is the first Shuttle Radar Topography Mission (SRTM) view of the Andes Mountains, the tallest mountain chain in the western hemisphere. This particular site does not include the higher Andes peaks, but it does include steep-sided valleys and other distinctive landforms carved by Pleistocene glaciers. Elevations here range from about 700 to 2,440 meters(2,300 to 8,000 feet). This region is very active tectonically and volcanically, and the landforms provide a record of the changes that have occurred over many thousands of years. Large lakes fill the broad mountain valleys, and the spectacular scenery here makes this area a popular resort destination for Argentinians.Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark, as would be the case at noon at this latitude in the southern hemisphere. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red, and magenta, to white at the highest elevations.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission aboard Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR)that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U

Aspectos que influyen en las estrategias de marketing de distribución y publicidad en Huancayo, Perú

Directory of Open Access Journals (Sweden)

José Maria Matas Castañeda

2013-06-01

Full Text Available El propósito de este artículo es analizar la situación actual de las principales estrategias de marketing en las variables de distribución y comunicación de Huancayo, capital del departamento de Junín, una de las más importantes zonas de los Andes Centrales del Perú. Esta región tiene como ciudad próxima de importancia a la ciudad de Lima, la capital peruana, que se encuentra a unas ocho horas con los medios de transporte actuales, después de atravesar los Andes y llegar hasta la costa. La mayoría de carreteras en los Andes y hasta la selva han sido sin asfaltar y complicadas aun los últimos años, por lo que el desplazamiento entre ciudades lo hacían pocas personas. Ello explica que tenga formas de distribución y comunicación propias. La llegada del primer centro comercial y la utilización de medios digitales están transformando las formas tradicionales de distribución y comunicación. El trabajo también analiza cómo se manifiesta la variable de comunicación en el marketing mix de las empresas huancaínas y cómo han influido la llegada de los medios digitales.

Chemical and isotopic investigations of runoff in a mountainous watershed, Venezuelan Andes (Rio Bocono)

International Nuclear Information System (INIS)

Cornieles, M.; Moreau, A.; Valles, V.; Travi, Y.

1999-01-01

The Rio Bocono watershed, located in the Western part of Venezuela on the South western side of Andes is considered by the 'Ministerio de1 Ambiente y de los Recursos Naturales Renovables' (MARN) as a priority zone for environmental management. The studies of relation between flow, dissolved elements and solid transport are essential to estimate soil degradation and sediment deposition which provokes loss of depth in the dam reservoir at the Southern margin of the basin. Because of the large surface which reach 1540 km 2 , the lack of equipment and the flash flood character of the river do not enable the flow mechanisms and transit times to be determined using usual hydrologic methods; therefore this problem has been approached by the way of chemical and isotopic investigation

La Cordillera Oriental Colombiana, Transecto Sumapaz

NARCIS (Netherlands)

Hammen, van der T.; Rangel, J.O.; Cleef, A.M.

2008-01-01

The publication of this volume (volume 7) concludes the publication of the study of the Transects of Buritaca (Sierra Nevada de Santa Marta), Parque Los Nevados (Cordillera Central), Tatamá (Western Cordillera) and Sumapaz (Eastern Cordillera) in the Colombian Andes. The latter three studies

New ICT in the Peruvian Andes: Theoretical Foundation and Bibliographical Balance

Directory of Open Access Journals (Sweden)

Mario Sánchez-Dávila

2016-04-01

Full Text Available On the one hand, this paper explains the theoretical foundations on which this proposal for digital anthropology in the Peruvian Andes is based (on the origins of digital anthropology, discussions on oral and written technology, and theories of digital technology as social practice. And, on the other hand, this paper presents a bibliographical balance of the studies on the new ICT in the Peruvian Andes (on identity expression, productive development and formal education in the Andean world.

DETERMINACIÓN DE SISTEMAS FISIOGRÁFICOS PARA EL MANEJO DE RECURSOS NATURALES EN CUENCAS HIDROGRÁFICAS. ARROYOS LOS BERROS Y VENTANA, RÍO NEGRO

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Ana Paula Salcedo

2007-12-01

Full Text Available El paisaje patagónico se caracteriza en líneas generales por la cordillera de los Andes al Oeste, las mesetas de origen sedimentario y basáltico en la porción central y los valles y faldeos dispuestos en sentido Oeste-Este. Dentro de la unidad de mesetas basálticas el macizo de Somuncura es el de mayor dimensión en la Patagonia, ocupando una importante superficie de las provincias de Río Negro y Chubut. El manto basáltico que lo constituye actúa como un gran reservorio del agua que infiltra producto de las precipitaciones, lo que da lugar a la formación de numerosas vertientes en la periferia de la meseta, siendo un importante recurso para el asentamiento humano y el desarrollo de actividades agrícolas y ganaderas. Sin embargo, durante las últimas décadas, distintos factores han confluido en detrimento de las potencialidades para el desarrollo rural en la región, conllevando a un progresivo despoblamiento, a la retracción de las actividades productivas e incluso al abandono de los campos.

Los sistemas geotermales del Pirineo central. I. Caracteres geoquímicos y fisicoquímicos de los manantiales termales

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Gómez, J.

1996-08-01

Full Text Available The compositional characters of selected hot springs from the Panticosa, Benasque, Arties, Caldas de Bohí, Luchon and Cauterets geothermal systems in the Central Pyrenees have been studied. All the springs have the same global geochemical features (high pH, low total dissolved solids, very low Mg concentrations, Na as the dominant cation, and absence of a dominant anion and belong to the same granite-related alkaline thermal waters group. Chemical composition of the springs is similar to each other, and to that found in other Pyrenean geothermal systems. A more detailed comparison shows, however, that Panticosa and Benasque systems have the lowest sodium and potassium concentrations found in any water belonging to the group of alkaline waters. Differences in pH values among the springs are related to emergence temperature as it occurs in the Pyrenean geothermal systems. According to the high pH of these waters, speciation calculations at emergence temperature show a very low CO2 partial pressure, dissolved silica partially ionized as H3Si04-, and Al(OH4- as the dominant aluminium species. Saturation indexes show that almost al1 the waters are highly oversaturated with quartz (close to equilibrium with chalcedony, potassium feldspar, and albite, which are the minerals equilibrated at depth with the solutions. Furthermore, all waters are in equilibrium with kaolinite and ca1cite at emergence conditions, showing the existence of a reequilibrium process during their ascent to the surface. This process happens to be one of the most important in the geochemical evo1ution of these alkaline systems.Las aguas de los sistemas geotermales de Panticosa, Benasque, Arties, Caldas de Bohí, Luchon y Cauterets en el Pirineo Central presentan rasgos geoquímicos similares (valores de pH elevados, bajo contenido de sólidos disueltos, muy bajas concentraciones de Mg, sodio como catión dominante y sin un anión en proporciones preponderantes sobre los dem

Pobladores de los andes. Entre la riqueza y la pobreza The inhabitants of the andes. Between wealth and poverty

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Aracely Burgos

2011-10-01

Full Text Available

Ecuador y los objetivos del milenio : inversiones para la conservación del agua

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Fabián Rodríguez

2013-09-01

Full Text Available El presente estudio analiza si se justifica la inversión en la protección del Sistema Nacional de Áreas Protegidas (SNAP. El nivel de inversión del Estado ecuatoriano fue estimado a partir de las necesidades de financiamiento del SNAP. Los beneficios económicos fueron estimados a partir de la oferta de agua de las áreas protegidas que se encuentran a lo largo de la Cordillera de los Andes. La metodología para evaluar si es conveniente o no la inversión del Estado en la protección del SNAP fue la relación beneficio - costo (B/C. Los resultados del estudio demuestran que solo los valores piso de la relación B/C justifican la inversión del Estado.

Phosphorus fractions and sorption dynamics in the sediments of two Ca-SO4 water reservoirs in the central Argentine Andes

Institute of Scientific and Technical Information of China (English)

José Gabriel León; Fernando Luis Pedrozo; Pedro Félix Temporetti

2017-01-01

Phosphorus (P) fractionation and sorption behavior were studied in the sediments of two calcium-sulfate (Ca-SO4:Ca2+170 mg L-1;SO42-400 mg L-1) water reservoirs in the southern central Argentine Andes-El Carrizal Reservoir (ECR),which stratifies in summer and El Nihuil Reservoir (ENR),which is vertically mixed throughout the year. Sediment size classes reflected the lithology of both basins and the reservoirs relative location:ECR (downstream from a valley adjacent to a mountain environment) had higher clay proportions while the sand fraction was more important in ENR (just next to a mountain environment). In both reservoirs, the chemical composition revealed low alteration and calcium enrichment. Total P content was relatively high (1.1–1.6 mg P kg-1 dry weight) as expected from the contribution of marine formations. P fractionation was dominated by Ca-P (ECR, 69%and ENR, 63%) followed by organic-P (23%) in summer-anoxic ECR and by iron/aluminum (Fe/Al)-P (27%) in oxic ENR. Batch experiments showed that sorption behavior in ECR had a typical Langmuir isotherm plot while in ENR that model fitted only at low dissolved P values (<5 mg P L-1) and co-precipitation evidence was observed at higher P con-centrations. It is proposed that lower Fe/Al-P content in anoxic (ECR) vs. oxic (ENR) sediments results from the P released from iron-bound phosphorus due to sulfate reduction-ferrous sulfide formation in an anoxic environment. This condition should enable ECR sediments to adsorb P into fresh oxidized iron, and ENR sediments to co-precipitate P with calcium due to Fe/Al-P saturation, as observed in batch experiments. This paper constitutes the first description of phosphorus content and dynamics in reser-voir sediments in arid central western Argentina, where water sulfate concentrations are naturally high due to basin lithology.

Cómo los indígenas mejoran su calidad de vida a través del desistimiento. Protección de reservas de agua en Ecuador

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Oliver Hoelcke

2013-09-01

Full Text Available La gente en Los Andes lucha por cada gota de agua. De ese líquido vital dependen cientos de miles de personas que habitan en el valle. Sin embargo, cada año llega menos agua a los pequeños poblados. Garantizar el abastecimiento del recurso es la meta de El Plan de Manejo Páramo.

Asynchronous Glacial Chronologies in the Central Andes (15-40°S) and Paleoclimatic Implications

Science.gov (United States)

Zech, R.; Kull, C.; Kubik, P. W.; Veit, H.

2006-12-01

We have established glacial chronologies along a N-S transect over the Central Andes using 10Be surface exposure dating. Our results show that maximum glacial advances occurred asynchronously and reflect the varying influence and shifts of the major atmospheric circulation systems during the Late Quaternary: the tropical circulation in the north and the westerlies in the south. In Bolivia (three research areas in the Cordillera Real and the Cordillera Cochabamba, ~15°S) glacial advances could be dated to ~20 and 12 ka BP. This is in good agreement with published exposure age data from moraines in Bolivia and Peru (provided that all ages are calculated following the same scaling system). Accordingly, the maximum glaciation there probably occurred roughly synchronous to the temperature minimum of the global Last Glacial Maximum (LGM) and the lateglacial cold reversals. Strict correlation with neither the Younger Dryas in the northern hemisphere, nor the Antarctic Cold Reversal is possible due to the current systematic exposure age uncertainties (~10%). Glacier-Climate-Modelling corroborates the sensitivity of the reconstructed glaciers to temperature changes, rather than precipitation. On the contrary, there is good evidence for the dominant role of precipitation changes on the glacial chronologies in the lee of the Cordillera Occidental, i.e. on the Altiplano and further south. The pronounced lateglacial wet phase, which is well documented in lake transgression phases as far south as 28°S (-> tropical moisture source), seems to have caused glacial advances even at ~30°S. In two research areas in Chile at that latitude, we were able to date several lateglacial moraines. Besides, the maximum datable glaciation there occurred at ~30 ka BP. That is significantly earlier than the LGM (sensu strictu) and points to favourable climate conditions for glaciation at that time (particularly increased precipitation). We conclude that the westerlies were more intensive or

Glacier shrinkage and water resources in the Andes

Science.gov (United States)

Francou, Bernard; Coudrain, Anne

For more than a century glaciers around the world have been melting as air temperatures rise due to a combination of natural processes and human activity. The disappearance of these glaciers can have wide-ranging effects, such as the creation of new natural hazards or changes in stream flow that could threaten water suppliesSome of the most dramatic melting has occurred in the Andes mountain range in South America. To highlight the climatic and glacial change in the Andes and to encourage the scientific community to strengthen the glacier observation network that stretches from Colombia to the Patagonian ice fields, the Instituto Nacional de Recursos Naturales (INRENA), Perú, and the Institute of Research and Development (IRD), France, recently organized the second Symposium on Mass Balance of Andean Glaciers in Huaráz,Perú.

Evidence for an Early-Middle Miocene age of the Navidad Formation (central Chile: Paleontological, paleoclimatic and tectonic implications Evidencias de una edad miocena temprana-media de la Formación Navidad: Implicancias paleontológicas, paleoclimáticas y tectónicas

Directory of Open Access Journals (Sweden)

Néstor M Gutiérrez

2013-01-01

Full Text Available The age of the Navidad Formation in central Chile has always been controversial, mainly due to the conflicting age ranges indicated by its macro- and microfossils. Macrofossils are generally interpreted as having been reworked from older, Early to Middle Miocene strata, whereas a Late Miocene-Pliocene age has been accepted on the basis of planktonic foraminifer index species. The results of this study, however, indicate that the macrofossils occur in situ, which necessitates a complete revision of the geochronological data. It is concluded that the evidence for an Early to Middle Miocene age is overwhelming, and that the planktonic foraminifer index species must have appeared in the SE Pacific earlier than elsewhere. These include Globoturborotalia apertura, Globorotalia puncticulata (Deshayes, Globorotalia spheriomizea (Walters, Neogloboquadrina pachyderma (Ehrenberg, and Neogloboquadrina acostaensis (Blow. An Early to Middle Miocene age for the Navidad Formation correlates well with a reinterpretation of its depo-sitional environment as a continental shelf instead of a deepwater continental slope, global and regional paleoclimatic events, and the tectonic development of the Andes Range.La edad de la Formación Navidad en Chile central siempre ha sido controversial, debido a los distintos rangos de edad indicados por los macro- y microfósiles. En general, se considera que los macro-fósiles han sido retrabajados de estratos del Mioceno Temprano a Medio, y se aceptó una edad miocena tardía para esta unidad sobre la base de especies indicadoras de foraminíferos planctónicos. Sin embargo, los resultados de este estudio indican que los macrofósiles ocurren in situ, lo cual hace necesario una revisión completa de los datos geocronológicos. Se concluye que la evidencia por una edad miocena temprana a media es contundente, y que los foraminíferos planctónicos que indicarían una edad miocena tardía aparecieron más temprano en el SE del oc

Validación del Cuestionario de Creencias Centrales de los Trastornos de la Personalidad (CCE-TP) en población colombiana

OpenAIRE

Londoño A., Nora Helena; Maestre C., Katherine; Marín M., Carlos Alberto; Schnitter C., Mónica; Castrillón M., Diego; Ferrer B., Alberto; Chaves C., Liliana

2007-01-01

Se construyó un cuestionario para evaluar creencias centrales asociadas con los trastornos de la personalidad, fundamentadas en el Modelo de la Terapia Cognitiva. Se realizó el análisis estructural y la validez de contenido de la prueba en población universitaria de la ciudad de Medellín, Colombia. La muestra fue representativa y elegida al azar a través de un procedimiento polietápico. Un número de 809 estudiantes universitarios contestaron el cuestionario de creencias centrales de los trast...

Validación del Cuestionario de Creencias Centrales de los Trastornos de la Personalidad (CCE-TP) en población colombiana

OpenAIRE

Nora Helena Londoño A.; Katherine Maestre C.; Mónica Schnitter C.; Diego Castrillón M.; Alberto Ferrer B.; Liliana Chavez C.

2010-01-01

Se construyó un cuestionario para evaluar creencias centrales asociadas con los trastornos de la personalidad, fundamentadas en el Modelo de la Terapia Cognitiva. Se realizó el análisis estructural y la validez de contenido de la prueba en población universitaria de la ciudad de Medellín, Colombia. La muestra fue representativa y elegida al azar a través de un procedimiento polietápico. Un número de 809 estudiantes universitarios contestaron el cuestionario de creencias centrales de los trast...

Late Cenozoic basin evolution and fold-thrust deformation in the southern Central Andes: Initial constraints from synorogenic deposits of the Precordillera, Argentina

Science.gov (United States)

Levina, M.; Horton, B. K.; Fuentes, F.; Stockli, D. F.

2012-12-01

In the Precordillera region of the Argentine Andes, Cenozoic shortening associated with flattening of the Pampean segment of the subducting Nazca plate has resulted in a series of thin skinned fold-thrust systems that partitioned and uplifted Cenozoic foreland basin deposits. The kinematic and temporal evolution of the Andean Precordillera can be approached through detailed analyses of the sedimentary fill now preserved in intermontane regions and the bedrock low-temperature thermochronology of the fold-thrust belt. In this project, we focus on Neogene foreland basin fill exposed in the central and eastern Precordillera along the San Juan River (Quebrada Albarracín and Pachaco regions), on the western flank of the Sierra Talacasto, and in the Loma de las Tapias area near the Ullum dam. The sedimentary successions exposed in these regions record the hinterland development of the Frontal Cordillera (detrital zircon provenance and composition of sandstone and conglomeratic units), regional volcanism (pyroclastic flows and tuffaceous sandstone units), and initial construction of the Precordillera (fault cutoff relationships, growth strata, and paleocurrent changes). We investigate the development and subsequent partitioning and deformation of these synorogenic sections using sediment provenance (detrital zircon U-Pb geochronology, conglomerate clast counts, sandstone petrography, and paleocurrent measurements), facies analysis of measured stratigraphic successions, and initial apatite (U-Th)/He cooling histories to constrain the age of uplift-induced exhumation of successive thrust sheets in the Andean Precordillera.

Summer energy balance and ablation of high elevation glaciers in the central Chilean Andes

Science.gov (United States)

Brock, Benjamin; Rivera, Andres; Burger, Flavia; Bravo, Claudio

2014-05-01

Glaciers of the semi-arid central Chilean Andes are an important freshwater source for the populous Central Valley region of Chile, but have been shrinking in recent decades. The surface energy balance of these glaciers is of high scientific interest as summer ablation occurs through both sublimation and melt. During the 2012-13 Austral Summer a glacio-meteorological monitoring programme was established on Olivares Alfa (3.9 km2, 4130-4800 m elevation) and Beta (8.3 km2, 3620-4850 m elevation) Glaciers and their forelands in the Upper Olivares Valley, 33°00'-33°11' S, 70°05'-70°15' W, approximately 50 km north-east of Santiago. This included complete automatic weather stations (AWSs) with sonic rangers to record surface ablation on the ablation zones of the two glaciers, and one AWS in the proglacial area of Olivares Alfa Glacier including precipitation gauge. To complement these point data, daily images of the glaciers were captured with fixed cameras in order to calculate snow cover and albedo distributions. To calculate the surface energy balance and rates of melt and sublimation, a model was developed which uses direct AWS measurements of the radiative fluxes and calculates the turbulent fluxes of sensible and latent heat using the bulk aerodynamic approach. The model also calculates the subsurface heat flux and includes a simple scheme to estimate refreezing of melt water within surface snow or ice. Meteorological data and model results for the December to May period will be presented in this paper. Model calculations match closely the cumulative ablation curve of the sonic ranger at Olivares Alfa, with a slight overestimation, and overestimate cumulative ablation recorded by the sonic ranger at Olivares Beta, possibly due, at least in part, to uncertain snow density values. Modelled cumulative ablation in the December-April period is 2.2 m water equivalent (w.e.) at Olivares Alfa (0.10 m sublimation, 2.10 m melt) and 2.34 m w.e. at Olivares Beta (0.18 m

Essential oils of medicinal plants from the central andes of Argentina: chemical composition, and antifungal, antibacterial, and insect-repellent activities.

Science.gov (United States)

Lima, Beatriz; López, Sandra; Luna, Lorena; Agüero, María B; Aragón, Liliana; Tapia, Alejandro; Zacchino, Susana; López, María L; Zygadlo, Julio; Feresin, Gabriela E

2011-05-01

The antifungal, antibacterial, and insect-repellent activities of the essential oils (EOs) of Acantholippia seriphioides, Artemisia mendozana, Gymnophyton polycephalum, Satureja parvifolia, Tagetes mendocina, and Lippia integrifolia, collected in the Central Andes area, province of San Juan, Argentina, were investigated. The dermatophytes Microsporum gypseum, Trichophyton mentagrophytes, and T. rubrum were inhibited by the EOs of G. polycephalum, L. integrifolia, and S. parvifolia, with minimum inhibitory concentrations (MICs) between 31.2 and 1000 μg/ml. Moreover, all EOs presented moderate activity against the bacteria tested, and the L. integrifolia and G. polycephalum EOs showed excellent repellent properties against Triatoma infestans, the Chagas disease vector, with repellency values between 60 and 100%. The A. seriphioides, G. polycephalum, and L. integrifolia EOs, obtained by hydrodistillation, were characterized by GC-FID and GC/MS analyses. The highest number of components (40) was identified in L. integrifolia EO, which, along with that of A. seriphioides, contained important amounts of oxygenated monoterpenes (44.35 and 29.72%, resp.). Thymol (27.61%) and carvacrol (13.24%) were the main components of A. seriphioides EO, and borneol, lippifoli-1(6)-en-5-one, and terpinen-4-ol (>8.5%) were the principal compounds of L. integrifolia EO. These results support the idea that oxygenated monoterpenes are the bioactive fractions of the EOs. Finally, the study shows that these Andean species might be used to treat superficial fungal infections and to improve the local Chagas disease situation by vector-control. Copyright © 2011 Verlag Helvetica Chimica Acta AG, Zürich.

Natural gas across the Andes : a case study of an international business venture

Energy Technology Data Exchange (ETDEWEB)

Figueroa, E.B.; Smith, B.

2002-07-01

This book describes the challenges and complexities of constructing the GasAndes pipeline from Argentinian gas fields across the Andes to Santiago in Chile. The project was a joint international effort between Canada's NOVA Corporation, Chile's Gasco and Gener, and Argentina's Compania General de Combustibles and Techint Compania Tecnica Internacional. The book relates how NOVA Gas International, together with its partners, accomplished the task of constructing the first major natural gas pipeline across the Andes mountains despite significant challenges such as steep mountain slopes, many river crossings, high altitude, high winds and bitter cold. It describes how the partnership developed and how political and socio-economic issues were dealt with. It demonstrates how business practices were modified to deal with local conditions and to ensure that the fragile environment of the Andean meadows was protected. It also describes how the builders of the pipeline addressed the concerns of communities along the pipeline route. The pipeline was constructed at a time when democracy was returning and market economies were shifting from a reduced role of government in the energy sector. The 463 km GasAndes pipeline has been in operation since August 7, 1997. refs., tabs., figs.

Gastrointestinal parasites of Lamas in the Bolivian Andes

DEFF Research Database (Denmark)

Nissen, Anne Malene; Nees, Ellinor Spörndly; Monrad, Jesper

A cross sectional study was conducted to determine prevalences and intensities of gastrointestinal (GIT) parasites in lamas in the Bolivian Andes. A quantitative and qualitative necro-copro-parasitlogical study was performed on 33 lamas between October and December 2007. At the time of necropsy t...

La Universidad colombiana y el fomento al espíritu empresarial en la década de los 80: Una perspectiva histórica y crítica

Directory of Open Access Journals (Sweden)

Luis ernesto Romero Ortiz

1988-04-01

Full Text Available RESUMEN El presente artículo resume los aspectos centrales de un trabajo de investigación realizado por el autor para el Magister en Dirección universitaria de la universidad de Los Andes de Bogotá. En el escrito se formula algunas tesis explicativas del resurgimiento del interés de la universidad Colombiana por el fomento al Espíritu empresarial, en especial la crisis económica, el desempleo profesional y la revisión del concepto  de la universidad acerca del papel  que debe  cumplir en el desarrollo del país. Se plantea igualmente la nueva estrategia de la relación universidad/ desarrollo que surge especialmente al interior de las facultades  de administración en la década de los ochenta y se llama a la reflexión sobre la necesidad de que esta acción de fomento al espíritu empresarial se asuma con todo el rigor académico para que sus resultados sean realmente una respuesta útil a las exigencias del país en un momento actual.

Meteorological Conditions of Floods In The Chilean Andes Mountains

Science.gov (United States)

Vergara, J.

Catastrophic floods occurred on mountains River during 2000 and 2001. The meteo- rological conditions of flood during the last five years have analyzed. For example, the flood of June 29 of 2000 occurred after one of extremely wettest June of the last 40 years were snowfall was 991cm in the Aconcagua Valley. Infrequently storms activ- ity generated a huge snowfall and rainfall over the Andes mountains on June of 2000 (1525mm in El Maule Valley) and the end of the unusually period, the flood was trig- gered by rising temperatures on the mountains and heavy rain (199mm in 24 hours) fall over the fresh snow on the morning of June 29 and floods wave developed and moved down along of the all river located on Central part of Chile, the foods peak was 2970.5m3/s on the El Maule basin in the morning of June 29. The regional meteoro- logical models with the hydrological forecasting was used for alert of the floods.

Reflections on Andes' Goal-Free User Interface

Science.gov (United States)

VanLehn, Kurt

2016-01-01

Although the Andes project produced many results over its 18 years of activity, this commentary focuses on its contributions to understanding how a goal-free user interface impacts the overall design and performance of a step-based tutoring system. Whereas a goal-aligned user interface displays relevant goals as blank boxes or empty locations that…

Attenuation tomography in the western central Andes: A detailed insight into the structure of a magmatic arc

Science.gov (United States)

Haberland, Christian; Rietbrock, Andreas

2001-06-01

High-quality data from 1498 local earthquakes recorded by the PISCO '94 (Proyecto de Investigatión Sismológica de la Cordillera Occidental, 1994) and ANCORP '96 (Andean Continental Research Project, 1996) temporary seismological networks allowed the detailed determination of the three-dimensional (3-D) attenuation structure (Qp-1) beneath the recent magmatic arc in the western central Andes (20° to 24°S). Assuming a frequency-independent Qp-1 in a frequency band between 1 and 30 Hz, whole path attenuation (t*) was estimated from the amplitude spectra of the P waves using spectral ratios and a spectral inversion technique. The damped least squares inversion (tomography) of the data reveals a complex attenuation structure. Crust and mantle of the forearc and subducting slab are generally characterized by low attenuation (Qp > 1000). Crust and mantle beneath the magmatic arc show elevated attenuation. The strongest anomaly of extremely low Qp is found in the crust between 22° and 23°S beneath the recent volcanic arc (Qp < 100). N-S variations can be observed: The western flank of the crustal attenuation anomaly follows the curved course of the volcanic front. North of 21°S the attenuation is less developed. In the northern part of the study area the low-Qp zone penetrates in the forearc mantle down to the subducting slab. In the south a deeper zone of high attenuation is resolved between 23° and 24°S directly above the subducting slab. Low Qp in the mantle correlates with earthquake clusters. The strong crustal attenuation is confined to the distribution of young ignimbrites and silicic volcanism and is interpreted as a thermally weakened zone with partial melts. The attenuation pattern in the upper mantle might reflect the variable extent of the asthenosphere and maps variations of subduction-related hydration processes in the mantle wedge from slab-derived fluids.

Between Andes and Amazon: the genetic profile of the Arawak-speaking Yanesha.

Science.gov (United States)

Barbieri, Chiara; Heggarty, Paul; Yang Yao, Daniele; Ferri, Gianmarco; De Fanti, Sara; Sarno, Stefania; Ciani, Graziella; Boattini, Alessio; Luiselli, Donata; Pettener, Davide

2014-12-01

The Yanesha are a Peruvian population who inhabit an environment transitional between the Andes and Amazonia. They present cultural traits characteristic of both regions, including in the language they speak: Yanesha belongs to the Arawak language family (which very likely originated in the Amazon/Orinoco lowlands), but has been strongly influenced by Quechua, the most widespread language family of the Andes. Given their location and cultural make-up, the Yanesha make for an ideal case study for investigating language and population dynamics across the Andes-Amazonia divide. In this study, we analyze data from high and mid-altitude Yanesha villages, both Y chromosome (17 STRs and 16 SNPs diagnostic for assigning haplogroups) and mtDNA data (control region sequences and 3 SNPs and one INDEL diagnostic for assigning haplogroups). We uncover sex-biased genetic trends that probably arose in different stages: first, a male-biased gene flow from Andean regions, genetically consistent with highland Quechua-speakers and probably dating back to Inca expansion; and second, traces of European contact consistent with Y chromosome lineages from Italy and Tyrol, in line with historically documented migrations. Most research in the history, archaeology and linguistics of South America has long been characterized by perceptions of a sharp divide between the Andes and Amazonia; our results serve as a clear case-study confirming demographic flows across that 'divide'. © 2014 The Authors. American journal of physical Anthropology published by Wiley Periodocals, Inc.

Las cuencas cenozoicas y su control en el volcanismo de los Complejos Nevados de Chillan y Copahue-Callaqui (Andes del Sur, 36-39°S Cenozoic basins and their control on volcanism of Nevados de Chillan and Copahue-Callaqui complexes (36-39°S, Southern Andes

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Juan Pablo Radic

2010-01-01

Full Text Available La Cordillera Principal de los Andes entre los 36° y 39°S constituye un excelente lugar para el estudio de la relación entre volcanismo y tectónica. Por medio del análisis tectonoestratigráfico de las cuencas cenozoicas se ha podido reconocer una clara coincidencia espacial entre estructuras de primer orden pertenecientes a estas cuencas y la distribución del volcanismo plio-pleistocénico. Las cuencas cenozoicas comenzaron su desarrollo durante el Oligoceno-Mioceno como depresiones extensionales, conformando un sistema de al menos tres subcuencas orientadas N-S y conectadas por dos zonas de acomodación estructural. Posteriormente este sistema de cuencas fue tectónicamente invertido hacia finales del Mioceno y los antiguos depocentros fueron deformados y exhumados, reutilizando las fallas originalmente extensionales. Las zonas de acomodación estructural permanecieron como estructuras de primer orden a escala de cuenca y constituyeron zonas de debilidad que favorecieron el posterior desarrollo del volcanismo y magma-tismo en los complejos volcánicos Nevados de Chillan y Copahue-Callaqui. Cada uno de estos complejos volcánicos se caracteriza por una orientación de sus centros de emisión, morfología y depósitos volcánicos en forma subparalela a la orientación de las zonas de acomodación estructural inmediatamente por debajo.The Cordillera Principal at 36° to 39°S is an excellent place to address the relationship between tectonics and volcanism. Based on tectonostratigraphic analysis of the Cenozoic basins it has been possible to recognize a clear spatial coincidence between first order basin scale structures and Plio-Pleistocene volcanism. Cenozoic basins started in the Oligocene-Miocene as extensional depocenters, characterized by at least three north-south oriented sub-basins connected by two structural accommodation zones. Towards the Late Miocene this extensional system was tectonically inverted deforming and uplifting the

Las dinámicas de comercialización de la quinua en los países andinos: ¿qué oportunidades y retos para la agricultura familiar campesina?

OpenAIRE

Baudoin, Andrea; Lacroix, Pierril; Bazile, Didier; Chia, Eduardo

2014-01-01

La revalorización de la quinua despierta muchos intereses tanto en los países andinos como europeos y americanos. Este producto andino antes marginado y circunscrito al autoconsumo ha entrado en la dieta de la población urbana de los países andinos y su consumo se difunde en EEUU, Europa y en otras partes del mundo. En los Andes los precios en chacra aumentan y el sector quinuero ha pasado a ser un sector atractivo para las inversiones. De esta chenopodiácea se está comercializando una gran v...

Diagnostic of annual cycle and effects of the ENSO about the maximum intensity of duration rains between 1 and 24 hours at the Andes of Colombia

International Nuclear Information System (INIS)

Poveda, German; Mesa, Oscar; Toro, Vladimir; Agudelo, Paula; Alvarez, Juan F; Arias, Paola; Moreno, Hernan; Salazar, Luis; Vieira, Sara

2002-01-01

We study the distribution of maximum rainfall events during the annual cycle, for storms ranging from 1 to 24-hour in duration; by using information over 51 rain gauges locate at the Colombian Andes. Also, the effects of both phases of ENSO (El Nino and La Nina) are quantified. We found that maximum rainfall intensity events occur during the rainy periods of march-may and September-November. There is a strong similarity between the annual cycle of mean total rainfall and that of the maximum intensities of rainfall over the tropical Andes. This result is quite consistent throughout the three ranges of the Colombian Andes. At inter annual timescales, we found that both phases of ENSO are associated with disturbances of maximum rainfall events; since during La Nina there are more intense precipitation events than during El Nino, overall, for durations longer than 3 hours, rainfall intensity gets reduced by one order of magnitude with respect to shorter durations (1-3 hours). The most extreme recorded rainfall events are apparently not associated with the annual and inter annual large scales forcing and appear to be randomly generated by the important role of the land surface atmosphere in the genesis and dynamics of intense storm over central Colombia

Conservación de los Bosques Relictos del NO de Perú

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Eric F. Rodríguez Rodríguez

2013-05-01

Full Text Available El presente documento resume las conclusiones obtenidas en el «Taller sobre Bosques Relictos de las Vertientes Occidentales Andinas del Norte del Perú y Sur del Ecuador», desarrollado en el marco del X Congreso Nacional de Botánica, Trujillo-Perú, el 04 de mayo del 2004. En este taller se llegaron a las siguientes conclusiones, dirigidas principalmente a los gobiernos regionales y concejos provinciales que incluyen a los departamentos de Cajamarca, Lambayeque, La Libertad y Piura: ·El Perú esta reconocido entre los países tropicales con mayor diversidad vegetal. La región norte del país incluye un porcentaje alto de esa diversidad. Entre los ecosistemas importantes que concentra la diversidad en esta región se encuentran los bosques relictos de la vertiente occidental de los Andes (Piura, Lambayeque, Cajamarca, La Libertad, considerados unos de los más altamente endémicos en todo el mundo. Estos bosques que se extienden hasta los 12°S, tienen tanto una diversidad muy elevada como un gran índice de endemismo. Muchas de estas especies están restringidas a bosques relictos individuales, tales como en los siguientes departamentos:

EVALUACIÓN DE LOS RIESGOS DE CONTAMINACIÓN MICROBIOLÓGICA EN LOS SISTEMAS HORTÍCOLAS, VALLE CENTRAL COSTA RICA

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Alfredo Durán-Quirós

2016-01-01

Full Text Available Durante 2012 y 2013 se realizó un estudio que abarcó 164 sistemas de producción de horta - lizas, ubicados en el Valle Central de Costa Rica. Su objetivo fue establecer si los productores cum - plen los puntos críticos relacionados con el riesgo de contaminación microbiológica. Se elaboró un listado de 38 eventos críticos ubicados a lo largo de toda la cadena de producción. Con ellos se diseñó una herramienta modalidad encuesta, para consultar a productores de tomate, chile dulce, lechuga, apio y culantro. Con los resultados se realizó un análisis de frecuencias, que demostró que la mayoría de los productores de tomate y de chile dulce utilizan abonos orgánicos que incluyen desechos animales. Además, se identi - ficó como problema principal la seria deficiencia sanitaria en el campo más que en la empacado - ra ya que el faltante de lavamanos es inferior que el de sanitarios. Por otra parte, la mayoría de los productores encuestados tienen animales domésticos sueltos en el área de producción. Alrededor del 30% de las empresas solo disponen de agua de río o acequia para las necesidades básicas del personal de campo. La mayoría de estas empresas, sin distingo de cultivo, utilizan como principal fuente de riego el agua de ríos y acequias. Solo un bajo porcentaje de las empresas evaluadas poseen un pozo o almacenan agua. Casi todas las fincas encuestadas están en áreas con altos niveles de población humana, presencia generalizada de casas de habitación y de fincas destinadas a producción animal. Se detectaron serios problemas de aseo de los recipientes plásticos utilizados en la cosecha. El estudio también confirmó la existencia de gran número de condiciones no adecuadas de manejo del cultivo, que incrementan el riesgo de que el producto hortícola sea contaminado.

Seasonal and elevational contrasts in temperature trends in Central Chile between 1979 and 2015

Science.gov (United States)

Burger, F.; Brock, B.; Montecinos, A.

2018-03-01

We analyze trends in temperature from 18 temperature stations and one upper air sounding site at 30°-35° S in central Chile between 1979-2015, to explore geographical and season temperature trends and their controls, using regional ocean-atmosphere indices. Significant warming trends are widespread at inland stations, while trends are non-significant or negative at coastal sites, as found in previous studies. However, ubiquitous warming across the region in the past 8 years, suggests the recent period of coastal cooling has ended. Significant warming trends are largely restricted to austral spring, summer and autumn seasons, with very few significant positive or negative trends in winter identified. Autumn warming is notably strong in the Andes, which, together with significant warming in spring, could help to explain the negative mass balance of snow and glaciers in the region. A strong Pacific maritime influence on regional temperature trends is inferred through correlation with the Interdecadal Pacific Oscillation (IPO) index and coastal sea surface temperature, but the strength of this influence rapidly diminishes inland, and the majority of valley, and all Andes, sites are independent of the IPO index. Instead, valley and Andes sites, and mid-troposphere temperature in the coastal radiosonde profile, show correlation with the autumn Antarctic Oscillation which, in its current positive phase, promotes subsidence and warming at the latitude of central Chile.

Especies de género Lutzomyia (Psychodidae, Phlebotominae en áreas de transmisión de leishmaniasis tegumentaria y visceral en el departamento de Santander, en la cordillera oriental de los Andes colombianos

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Claudia Magaly Sandoval

2006-10-01

Full Text Available Introducción. Los flebótomos desde el punto de vista de salud pública son especialmente conocidos como los únicos insectos vectores de las leishmaniasis y demuestran una interesante biodiversidad en algunas zonas como la cordillera de los Andes en Suramérica. Este estudio presenta las especies de flebótomos organizadas por municipios y zonas endémicas que pueden encontrarse en el departamento de Santander, ubicado sobre la cordillera oriental andina en Colombia. Objetivo. Presentar una actualización del inventario de las especies del género Lutzomyia en el departamento de Santander,señalar la distribución y discutir algunos aspectos de la ecología de las especies de mayor importancia en salud pública. Materiales y métodos. Durante 1998 a 2001 en 12 municipios se realizaron capturas de flebótomos utilizando trampas de luz tipo CDC miniatura, entre las 19:00-6:00 horas, también capturas con cebo humano protegido utilizando aspiradores manuales entre las 18:00-20:00 horas, ocasionalmente aspiración directa sobre troncos de árboles entre las 8:00-11:00 horas y capturas de flebótomos en reposo sobre las paredes en horario diurno. Resultados. Se capturaron un total de 3.972 flebótomos distribuidos en 41 especies; de éstas, 16 especies son nuevos registros para esta región del país. En las zonas consideradas endémicas para leishmaniasis tegumentaria americana se destacaron por su abundancia, presencia en el intradomicilio e importancia epidemiológica L. gomezi, L. trapidoi, L. panamensis, L. ovallesi y L. yuilli yuilli. En las zonas de leishmaniasis visceral americana predominó L. longipalpis.

Glacier loss and hydro-social risks in the Peruvian Andes

Science.gov (United States)

Mark, Bryan G.; French, Adam; Baraer, Michel; Carey, Mark; Bury, Jeffrey; Young, Kenneth R.; Polk, Molly H.; Wigmore, Oliver; Lagos, Pablo; Crumley, Ryan; McKenzie, Jeffrey M.; Lautz, Laura

2017-12-01

Accelerating glacier recession in tropical highlands and in the Peruvian Andes specifically is a manifestation of global climate change that is influencing the hydrologic cycle and impacting water resources across a range of socio-environmental systems. Despite predictions regarding the negative effects of long-term glacier decline on water availability, many uncertainties remain regarding the timing and variability of hydrologic changes and their impacts. To improve context-specific understandings of the effects of climate change and glacial melt on water resources in the tropical Andes, this article synthesizes results from long-term transdisciplinary research with new findings from two glacierized Peruvian watersheds to develop and apply a multi-level conceptual framework focused on the coupled biophysical and social determinants of water access and hydro-social risks in these settings. The framework identifies several interacting variables-hydrologic transformation, land cover change, perceptions of water availability, water use and infrastructure in local and regional economies, and water rights and governance-to broadly assess how glacier change is embedded with social risks and vulnerability across diverse water uses and sectors. The primary focus is on the Santa River watershed draining the Cordillera Blanca to the Pacific. Additional analysis of hydrologic change and water access in the geographically distinct Shullcas River watershed draining the Huaytapallana massif towards the city of Huancayo further illuminates the heterogeneous character of hydrologic risk and vulnerability in the Andes.

Records of new or poorly known migratory birds from Laguna del Otun, Los Nevados National Natural Park, Risaralda, Colombia

International Nuclear Information System (INIS)

Acevedo Charry, Orlando; Matta Camacho, Nubia E; Moncada Alvarez, Ligia Ines

2013-01-01

Colombia is important for migratory birds. Despite this, we do not know where they are during their crossing or residency in the country, and which species use paramo. We registered new migratory bird species for Laguna Del Otun, immersed in a complex of wetlands declared a Ramsar site since 2008. The lagoon is located in the Los Nevados National Natural Park at 3932 m asl, in paramo ecosystems of the Central Andes of Colombia. During five field trips between 2010-2012 we recorded four new migratory bird species for the park: Anas acuta, Pandion haliaetus, Riparia riparia, and Dendroica petechia. We also registered an altitudinal range extension for two additional migratory species which had only been recorded below 3500 m: Tringa flavipes and Hirundo rustica. These findings suggest these species could tolerate high mountain conditions and use the paramo. It's needed inquiry about migratory dynamics and high mountain habitat use by migratory birds.

Dynamics of a Puelche foehn event in the Andes

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Lea Beusch

2018-01-01

Full Text Available In this numerical modelling study, we investigate a Puelche foehn event (25–26 March 2014 in the southern Andes – a region with sparse observations. The synoptic environment as well as the mesoscale structure and the dynamics of the easterly wind are examined with European Centre for Medium-Range Weather Forecasts (ECMWF analyses and a simulation with the mesoscale non-hydrostatic limited-area weather prediction model COSMO with a grid spacing of 2.2 km.The large-scale synoptic situation leading to this Puelche event is characterized by a mid-tropospheric cut-off low above the mountain range, the formation of a coastal surface low, as well as high pressure extending over the southern Andes. Easterly winds extend throughout the entire troposphere, indicative of a deep foehn flow. In the free troposphere, the easterlies are geostrophically balanced and develop in association with increasing pressure to the south. In contrast, within the planetary boundary layer, the easterly winds occur predominantly due to an increasing cross-range large-scale pressure gradient with only a weak geostrophic component. Kinematic trajectories indicate that a significant part of the Puelche air mass originates from above an inversion on the upstream side of the Andes. Some air parcels, however, ascend on the upstream side to crest height as the boundary layer deepens during daytime and/or flow through gaps across the mountain range. Hence, this Puelche event shares characteristics of both a blocked and a non-blocked foehn type.

Radical, reformist and aborted liberalism: origins of national regimes in Central America Liberalismo radical, reformista y frustrado: orígenes de los regímenes nacionales en América central

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James MAHONEY

2011-06-01

Full Text Available During the twentieth century, the countries of Central America were characterized by remarkably different political regimes: military-authoritarianism in Guatemala and El Salvador, progressive democracy in Costa Rica and traditional-authoritarianism in Honduras and Nicaragua. This article explains these contrasting regime outcomes by exploring the agrarian and state-building reforms pursued by political leaders during the nineteenth– and early twentieth century liberal reform period. Based on differences in the transformation of state and class structures, three types of liberalism are identified: radical liberalism in Guatemala and El Salvador, reformist liberalism in Costa Rica and aborted liberalism in Honduras and Nicaragua. It is argued that these types of liberalism set the Central American countries on contrasting paths of political development, culminating in diverse regime outcomes.Durante el siglo XX, los países de América Central se caracterizaron por tener regímenes políticos muy diferentes: el autoritarismo militar en Guatemala y El Salvador; la democracia progresista en Costa Rica y el autoritarismo tradicional en Honduras y Nicaragua. Este artículo explica los resultados de estos distintos regímenes mediante la exploración de las reformas agrarias y de la construcción del Estado llevadas a cabo por los líderes políticos durante el siglo XIX y principios del periodo de reformas liberales del siglo XX. Basándose en las diferencias de la transformación del Estado y de las estructuras de clases, se pueden identificar tres tipos de liberalismo: liberalismo radical en Guatemala y El Salvador; liberalismo reformista en Costa Rica y liberalismo frustrado en Honduras y Nicaragua. Se argumenta que estos tipos de liberalismo condujeron a los países de América Central a caminos contrarios al desarrollo político, culminando así en regímenes con resultados diversos.

Paleozoic evolution of active margin basins in the southern Central Andes (northwestern Argentina and northern Chile)

Science.gov (United States)

Bahlburg, H.; Breitkreuz, C.

The geodynamic evolution of the Paleozoic continental margin of Gondwana in the region of the southern Central Andes is characterized by the westward progression of orogenic basin formation through time. The Ordovician basin in the northwest Argentinian Cordillera Oriental and Puna originated as an Early Ordovician back-arc basin. The contemporaneous magmatic arc of an east-dipping subduction zone was presumably located in northern Chile. In the back-arc basin, a ca. 3500 meter, fining-up volcaniclastic apron connected to the arc formed during the Arenigian. Increased subsidence in the late Arenigian allowed for the accomodation of large volumes of volcaniclastic turbidites during the Middle Ordovician. Subsidence and sedimentation were caused by the onset of collision between the para-autochthonous Arequipa Massif Terrane (AMT) and the South American margin at the Arenigian-Llanvirnian transition. This led to eastward thrusting of the arc complex over its back-arc basin and, consequently, to its transformation into a marine foreland basin. As a result of thrusting in the west, a flexural bulge formed in the east, leading to uplift and emergence of the Cordillera Oriental shelf during the Guandacol Event at the Arenigian-Llanvirnian transition. The basin fill was folded during the terminal collision of the AMT during the Oclóyic Orogeny (Ashgillian). The folded strata were intruded post-tectonically by the presumably Silurian granitoids of the "Faja Eruptiva de la Puna Oriental." The orogeny led to the formation of the positive area of the Arco Puneño. West of the Arco Puneño, a further marine basin developed during the Early Devonian, the eastern shelf of which occupied the area of the Cordillera Occidental, Depresión Preandina, and Precordillera. The corresponding deep marine turbidite basin was located in the region of the Cordillera de la Costa. Deposition continued until the basin fill was folded in the early Late Carboniferous Toco Orogeny. The basin

L'enfant et le terroir. La construction de l'identité paysanne dans une communauté des Andes péruviennes

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1995-01-01

Full Text Available Cet article propose quelques pistes de travail sur l'identité et la notion de personne à partir de l'étude du statut de l'enfant. L'auteur montre notamment comment le lieu de naissance établit les bases de l'identité paysanne andine en inscrivant le nouveau-né dans un triple environnement (social, familial, mythique qui définit son appartenance à la lignée paternelle ou maternelle et, au-delà du groupe lignager, à la communauté. EL NIÑO Y LA TIERRA. LA CONSTRUCCIÓN DE LA IDENTITAD CAMPESINA EN UNA COMUNIDAD DE LOS ANDES PERUANOS. Este artículo propone algunas pistas de investigación sobre la identidad y la noción de persona a partir del estudio del estatus del niño. La autora muestra en particular cómo el lugar de nacimiento establece las bases de la identidad campesina andina al ubicar al recién nacido en un triple entorno (el grupo social, la familia y los mitos que define su pertenencia a la rama paterna y, más allá del linaje a la comunidad. THE CHILD AND THE LAND. THE CONSTRUCTION OF PEASANT’S IDENTITY IN A COMMUNITY OF THE PERUVIAN ANDES. This paper proposes a few lines of research about identity and the notion of the human being based on the study of the status of the infant. The author shows how birth-place establishes the basis of Andean peasant's identity by allowing the infant to fit into a triple environment (the social group, the extended family and the myths. This environment defines if infant belongs to the paternal or maternal line and, beyond the lineage, to the community.

Impacto económico del tratamiento y gestión de los residuos sólidos producidos por el Hospital Militar Central – Lima

OpenAIRE

Nava Torres, César Augusto; Nava Torres, César Augusto; Loayza Berrocal, Luis Alberto; Nava Torres, César Augusto

2012-01-01

El manejo de los residuos sólidos hospitalarios en nuestro país es uno de los aspectos de la gestión hospitalaria que ha ido tomando importancia e interés en los últimos años. Mediante la presente investigación se pretende evaluar el actual Tratamiento y Gestión de los residuos sólidos en el Hospital Militar Central (HMC) de la ciudad de Lima, analizando los servicios de salud donde los pacientes se hospitalizan y se genere la mayor cantidad de desechos, a fin de determinar las ganancias...

Retroceso de glaciares en el Perú: consecuencias sobre los recursos hídricos y los riesgos geodinámicos

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1995-01-01

Full Text Available RECUL DES GLACIERS AU PÉROU : CONSÉQUENCES SUR LES RESSOURCES EN EAU ET LES RISQUES GÉODYNAMIQUES. Les Andes du Pérou possèdent encore entre 4 500 et 6 700 m d’importantes masses glaciaires. Sur quelques glaciers représentatifs, on a mesuré un recul important ces dernières décennies, ce qui a provoqué et continue à provoquer la formation de nouveaux lacs glaciaires, certains d’entre eux constituant un danger permanent. D’autre part cette évolution, si elle persiste, aura tendance à diminuer l’alimentation des cours d’eau, ce qui va se marquer surtout pendant la période d’étiage. On apporte quelques données sur le recul des langues glaciaires en Cordillère Blanche. La connaissance du phénomène a permis d’entreprendre des actions visant à réduire, voire supprimer le danger que représentent ces lacs. Dans le même temps, on en a profité pour construire des retenues permettant de stocker l’eau et de répondre dans des meilleures conditions à la demande venant de divers secteurs, comme l’agriculture, la consommation domestique, l’énergie et l’industrie. Los Andes peruanos poseen todavía importantes masas glaciares entre los 4 500 y 6 700 msnm. En algunos glaciares representativos se ha medido estos últimos decenios un retroceso marcado, lo cual ha ocasionado, y actualmente continúa originando, la formación de nuevas lagunas, algunas de ellas con condiciones de peligrosidad latente. Por otro lado, si esta evolución permanece, puede provocar una disminución del recurso hídrico que abastece a los ríos, que sería muy sensible durante la época de estío. Se muestra en forma sucinta datos acerca del retroceso de algunos glaciares en la Cordillera Blanca. Con el conocimiento del fenómeno que viene ocurriendo se han tomado acciones relacionadas a disminuir o evitar los riesgos representados por las lagunas peligrosas. Al mismo tiempo, aprovechando estas reservas de agua, se construyen pequeños embalses para

Rapid Diversification and Time Explain Amphibian Richness at Different Scales in the Tropical Andes, Earth's Most Biodiverse Hotspot.

Science.gov (United States)

Hutter, Carl R; Lambert, Shea M; Wiens, John J

2017-12-01

The Tropical Andes make up Earth's most species-rich biodiversity hotspot for both animals and plants. Nevertheless, the ecological and evolutionary processes underlying this extraordinary richness remain uncertain. Here, we examine the processes that generate high richness in the Tropical Andes relative to other regions in South America and across different elevations within the Andes, using frogs as a model system. We combine distributional data, a newly generated time-calibrated phylogeny for 2,318 frog species, and phylogenetic comparative methods to test the relative importance of diversification rates and colonization times for explaining Andean diversity at different scales. At larger scales (among regions and families), we find that faster diversification rates in Andean clades most likely explain high Andean richness. In contrast, at smaller temporal and spatial scales (within family-level clades within the Andes), diversification rates rarely explain richness patterns. Instead, we show that colonization times are important for shaping elevational richness patterns within the Andes, with more species found in habitats colonized earlier. We suggest that these scale-dependent patterns might apply to many other richness gradients. Recognition of this scale dependence may help to reconcile conflicting results among studies of richness patterns across habitats, regions, and organisms.

An InSAR survey of the central Andes: Constraints on magma chamber geometry and mass balance in a volcanic arc

Science.gov (United States)

Pritchard, M. E.; Simons, M.

2002-12-01

The central Andes (14-28o S) has a high density of volcanoes, but a sparse human population, such that the activity of most volcanoes is poorly constrained. We use InSAR to conduct the first systematic observations of deformation at nearly 900 volcanoes (about 50 of which are classified ``potentially active'') during the 1992-2002 time interval. We find volcanic deformation in four locations. Subsidence is seen at Robledo (or Cerro Blanco) caldera, Argentina. We observe inflation at the stratovolcano Uturuncu, Bolivia, near stratovolcano Hualca Hualca, Peru, and in a region not associated with any known edifice on the border between Chile and Argentina that we call ``Lazufre'' because it lies between volcanoes Lastarria and Cordon del Azufre. The deformation pattern can be well explained by a uniform point-source source of inflation or deflation, but we compare these model results with those from a tri-axial point-source ellipsoid to test the robustness of estimated source depth and source strength (inferred here to be volume change). We further explore the sensitivity of these parameters to elastic half-space and layered-space models of crustal structure, and the influence of local topography. Because only one satellite look direction is available for most time periods, a variety of models are consistent with our observations. If we assume that inflation is due solely to magmatic intrusion, we can compare the rate of magma intrusion to volcanic extrusion during the decade for which data is available and the longer-term geologic rate. For the last decade, the ratio of volume intruded to extruded is between about 1-10, which agrees with previous geologic estimates in this and other volcanic arcs. The combined rate of intrusion and extrusion is within an order of magnitude of the inferred geologic rate.

Developing services for climate impact and adaptation baseline information and methodologies for the Andes

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Huggel, C.

2012-04-01

Impacts of climate change are observed and projected across a range of ecosystems and economic sectors, and mountain regions thereby rank among the hotspots of climate change. The Andes are considered particularly vulnerable to climate change, not only due to fragile ecosystems but also due to the high vulnerability of the population. Natural resources such as water systems play a critical role and are observed and projected to be seriously affected. Adaptation to climate change impacts is therefore crucial to contain the negative effects on the population. Adaptation projects require information on the climate and affected socio-environmental systems. There is, however, generally a lack of methodological guidelines how to generate the necessary scientific information and how to communicate to implementing governmental and non-governmental institutions. This is particularly important in view of the international funds for adaptation such as the Green Climate Fund established and set into process at the UNFCCC Conferences of the Parties in Cancun 2010 and Durban 2011. To facilitate this process international and regional organizations (World Bank and Andean Community) and a consortium of research institutions have joined forces to develop and define comprehensive methodologies for baseline and climate change impact assessments for the Andes, with an application potential to other mountain regions (AndesPlus project). Considered are the climatological baseline of a region, and the assessment of trends based on ground meteorological stations, reanalysis data, and satellite information. A challenge is the scarcity of climate information in the Andes, and the complex climatology of the mountain terrain. A climate data platform has been developed for the southern Peruvian Andes and is a key element for climate data service and exchange. Water resources are among the key livelihood components for the Andean population, and local and national economy, in particular for

Orden monetario y bancos centrales Monetary order and Central Banks

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Aglietta Michel

1996-06-01

Full Text Available Con el enfoque evolucionista e institucionalista de la economía de las convenciones francesa, este trabajo analiza el surgimiento histórico de la banca central y la creación institucional del 'arte de la banca central'. El artículo estudia los modelos formales del orden monetario, la banca libre y la banca central, y analiza los eventos históricos que llevaron a que el Banco de Inglaterra inventara el arte de manejar los bancos centrales en conjunción con el aprendizaje colectivo e institucional que lo hizo posible. Aglietta muestra que la banca central no es una creación del Estado sino una creación institucional endógena al sistema de mercado.With the evolutionist and institutionalist focus of the economics of the French conventions, this paper analyzes the historical rise of the central bank and the institutional creation of the 'art of the central bank'. The article studies formal models of the monetary order, free banking and the central bank, and analyzes the historie events that led to the Bank of England inventing the art of managing the central banks, in conjunction with the collective and institutional learning that made it possible. Aglietta shows that the central bank is not a creation of the State, but rather aninstitutional creation endogenous to the market system.

Manejo y conservación del suelo y agua en los Andes del Sur de Ecuador

OpenAIRE

Ochoa Cueva, Pablo Alejandro

2016-01-01

El manejo y la conservación de los recursos suelo y agua han sido y son motivo de gran preocupación para la sostenibilidad del Planeta en cuanto a la soberanía alimentaria y el desarrollo de la vida en general, esto se remarca en los países en vías de desarrollo que presentan fuertes contrastes, como lo es el Ecuador. Las limitaciones en la recolección de los datos climatológicos, de suelo, cobertura vegetal, entre otros; así como la aplicación de metodologías que se adapten a las realidades ...

Los Procesos Electorales Centroamericanos en la Década de los 80

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Fernando HARTO DE VERA

2009-11-01

Full Text Available RESUMEN: En este artículo se traza cuales han sido los resultados de los distintos procesos electorales que han tenido lugar durante la década de los ochenta en Centroamérica.ABSTRACT: In this article, the author describes the electoral results of the elections in Central America in the eighties.

Black carbon and other light-absorbing impurities in the Andes of Northern Chile

Science.gov (United States)

Rowe, P. M.; Cordero, R.; Warren, S. G.; Pankow, A.; Jorquera, J.; Schrempf, M.; Doherty, S. J.; Cabellero, M.; Carrasco, J. F.; Neshyba, S.

2015-12-01

Black carbon (BC) and other light-absorbing impurities in snow absorb solar radiation and thus have the potential to accelerate glacial retreat and snowmelt. In Chile, glaciers and seasonal snow are important sources of water for irrigation and domestic uses. In July 2015 (Austral winter) we sampled snow in the western Andes in a north-south transect of Chile from 18 S to 34 S. Most of the sampled snow had fallen during a single synoptic event, during 11-13 July. The snow was melted and passed through 0.4 micrometer nuclepore filters. Preliminary estimates indicate that (1) the ratio of BC to dust in snow increases going south from Northern to Central Chile, and (2) in snow sampled during the two weeks following the snowstorm, the impurities were concentrated in the upper 5 cm of snow, indicating that the surface layer became polluted over time by dry deposition.

Carbunco: una investigación clínica en los andes peruanos

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David Salinas

2004-12-01

Full Text Available Objetivo: Describir las características clínicas del carbunco (ántrax en los pacientes de una zona de altura peruana. Material y Métodos: Se captó veintinueve casos sospechosos de carbunco cutáneo, todos residentes de Santiago de Chocorvos. En once pacientes se realizó un estudio histopatológico de las lesiones cutáneas, en seis casos un estudio con coloración de Gram de frotises de lesiones cutáneas. Resultados: Todos los pacientes presentaron una infección limitada a nivel cutáneo. Las lesiones se iniciaban con mácula asociada a parestesias o prurito; posteriormente, evolucionaba a una pápula y luego a una úlcera; inicialmente, el fondo de la úlcera era cubierta con una escara de color amarillento, para luego adquirir un color negruzco. Una imagen sugestiva de B. anthracis fue identificada en la coloración Gram de una lesión cutánea. Conclusiones: El carbunco es una zoonosis que puede ocurrir en zonas de elevada altitud. Las características clínicas del carbunco cutáneo en la altura son similares a las descritas en la literatura científica.

Función pulmonar en niños sanos de 7 y 8 años de las comunas de Cerro Navia y Los Andes expuestos a diferentes niveles de contaminación por MP10

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Daniel Cebulj Navarrete

2011-01-01

Full Text Available Objetivo: Determinar si difieren los valores espirométricos evaluados en niños sanos de 7- 8 años provenientes de comunas con niveles históricos de alta versus baja contaminación atmosférica en Chile. Materiales y métodos: Estudio descriptivo, no experimental, exploratorio y transversal y ex post facto causa y efecto. Se realizaron en total 261 encuestas de salud respiratoria y calificaron, según criterios de inclusión, 110 niños sanos de 7 y 8 años (55 niños en cada comuna. Se realizaron exámenes espirométricos: Con espirómetro de turbina SPIROBANK G, considerando variables VEF1, FEF25-75, PEF y CVF. La obesidad, actividad física, contaminación intramuros por calefacción y exposición a humo de tabaco también fueron descritas. Resultados: Las variables espirométricas analizadas VEF1 y FEF25-75 mostraron diferencias significativas (p<0.05 y PEF mostró diferencias altamente significativas (p <0.005 según localidad, es decir, que la media de estas variables en Los Andes, comuna agroindustrial con baja contaminación atmosférica, es mayor que la de Cerro Navia, comuna con altos niveles de contaminación del aire. En la variable PEF se encontró, además, significancia entre género. La CVF no presentó diferencia entre comunas. Conclusiones: Los niños sanos de 7 y 8 años que habitan en comunas donde la exposición a contaminación atmosférica es alta presentan una menor función pulmonar comparada con los niños sanos, de similares características, que habitan en comunas con bajos niveles de contaminación atmosférica. Existen otros factores que podrían influir en el detrimento de la función pulmonar y que en este estudio fueron descritos como factores confundentes.

Los mamíferos marinos en la costa central de Oaxaca Marine mammals along the central coast of Oaxaca

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Juan Meraz

2008-06-01

Full Text Available Con la finalidad de conocer las especies de mamíferos marinos que se encuentran en la costa central de Oaxaca, se elaboró un listado comentando las características de los registros obtenidos. Se incluyeron las observaciones hechas a lo largo de 30 recorridos por mar, entre junio de 1999 y enero de 2004, realizadas entre las bahías de Huatulco y la playa de La Escobilla. Adicionalmente se incluyeron registros de animales varados, así como observaciones realizadas desde la costa. Se presentan comentarios sobre el registro de 8 especies en la zona, incluyendo las localidades y fechas de los avistamientos. Stenella attenuata es la especie más abundante, y la zona de Zipolite-Isla Roca Blanca la localidad con el mayor número de avistamientos. Dado el crecimiento turístico del lugar, es importante contar con este tipo de registros ya que es poco lo que se sabe sobre estas especies en esta porción de la costa oaxaqueña.With the aim of documenting the species of marine mammals that occur along the central coast of Oaxaca, a list with the characteristics of the records was elaborated based on observations made throughout 30 surveys from Huatulco Bays to La Escobilla beach between June 1999 and January 2004. Additional records from stranded animals are included, as well observations from the coast. Comments on 8 species are presented, including localities and dates of sightings. Stenella attenuata is the most abundant species. Zipolite-Roca Blanca island was the locality with the highest number of sightings. This records are important to promote conservation due growth of tourism in the area, given that Oaxaca coast is poorly known regarding marine mammals.

The Under-side of the Andes: Using Receiver Functions to Map the North Central Andean Subsurface

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Ryan, J. C.; Beck, S. L.; Zandt, G.; Wagner, L. S.; Minaya, E.; Tavera, H.

2012-12-01

The Central Andean Uplift and Geodynamics of High Topography (CAUGHT) project is an interdisciplinary project to investigate connections between lithospheric removal, crustal shortening and surface uplift in the northern Bolivia and southern Peru region of the South American Andean orogen. The central Andes are defined by six major tectonomorphic provinces; the forearc, the volcanically active Western Cordillera (WC, ~6 km elevation), the internally drained Altiplano (~4 km elevation), an inactive fold and thrust belt in the Eastern Cordillera (EC, ~6 km elevation), a lower elevation active fold and thrust belt in the Subandean (SA) zone and the Beni, a foreland basin. Forty seismic stations installed for the CAUGHT project were deployed between 13° and 18° S latitude, covering the transition zone where the Altiplano region pinches out in southern Peru, in an effort to better constrain the changing character of the crust and mantle lithosphere. Geologic studies across the northern Bolivian portion of the eastern Andean margin (15-17° S) have documented a total of 275 km of upper crustal shortening (McQuarrie et al, Tectonics, v27, 2008), which may be associated with crustal thickening and/or the removal of lithospheric material as a thickened lithosphere root becomes unstable. For this receiver function (converted wave) study, we have little coverage in the forearc and foreland, ~75 km spacing in most of the array, and a relatively dense ~20 km spaced profile along the Charaña-La Paz-Yucumo transect, the eastern portion of which is nearly coincident with the balanced cross-section of McQuarrie et al. (2008). Using the first year of available data, more than 1200 receiver functions have been calculated using an iterative deconvolution method, and stacked using the common conversion point (CCP) method, along profiles parallel to and nearly coincident to those used for the geologic shortening estimates. We identified arrivals for the Moho and generated a 3D map of

Glacial recession in the Tropical Andes from the Little Ice Age: the case of Ampato Volcanic Complex (Southern Peru

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Alcalá, J.; Palacios, D.; Zamorano, J. J.

2010-03-01

Data published over the last decade reveal substantial glacial recession in the tropical Andes since the Little Ice Age (LIA), (Ramirez, et al., 2001; Rabatel, et al., 2005; Rabatel, et al., 2008; Vuille, et al., 2008; Hastenrath, 2009; Jomelli, et al., 2009), and a growing rate of recession since the 1980’s caused by global warming (Ramirez, et al., 2001; Vuille, et al., 2008). Today there is great interest in the evolution of these ice masses due to heightened awareness of climate change and of the strategic importance that glaciers have as a hydrologic resource for communities in arid climate zones in the tropical Andes (Mark, 2008; Vuille et al., 2008). Cordillera Blanca forms part of the Andes Mountains of northern Peru, and is a chosen site for many studies on glacier evolution. Vuille et al. 2008 determined that a considerable area of ice mass was lost at Huascarán-Chopicalqui glacier (18% from 1920-1970) and Astesonraju glacier (20% from 1962-2003). Studies at Coropuna volcano, which has the most extensive glacier field in the western range of southern Peru, also report a strong melting trend that began with only minimal recession from 1955-1986 (4%), but increased to 14% from 1986-2007 (Úbeda et al., 2009). Only a few of the Andes glaciers are consistently monitored, and the most comprehensive data are for Chacaltaya and Zongo glaciers (16º S) in Bolivia. Since the maximum LIA, Chacaltaya has lost 89% of its surface area, particularly in recent years. By 1983, the totaled loss was five times the shrinkage for the period 1940-1963 (Ramirez, et al., 2001). Zongo glacier maintained equilibrium from 1956-1975, but later experienced a period dominated by continuous recession (Soruco, et al., 2009). This study expands current knowledge of glacier evolution since the LIA in the Central Volcanic Zone (CVZ; 14º - 27º S) (Stern, 2004) of the Andes. The study site was chosen in an area that had never been used for preliminary research of this type, concretely

La arquitectura de los puestos de pastoreo en las tierras altas del norte argentino (Susques, provincia de Jujuy

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Jorge Tomasi

2015-06-01

Full Text Available En este artículo nos proponemos analizar las características que presentan los puestos de pastoreo en las tierras altas de la provincia de Jujuy, en el noroeste argentino. El análisis considerará las lógicas de emplazamiento, las configuraciones y las materialidades de estos puestos. Tomaremos en cuenta particularmente los sentidos que la topografía tiene en la configuración de la arquitectura doméstica. Estas construcciones tienen un sentido específico en el marco de los sistemas de asentamiento de los grupos pastoriles, en relación con las estrategias de movilidad de las familias junto con los rebaños. El estudio se basa en el material del trabajo de campo etnográfico que se ha venido desarrollando desde el 2004 en la localidad de Susques, el cual ha implicado un relevamiento sistemático de los distintos tipos de asentamiento, en el marco de una investigación sobre las espacialidades y la arquitectura pastoril en los Andes.

Santuarios, peregrinaciones y fiestas patronales en la cultura regional boyacense

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Cesar Moreno

2005-10-01

Full Text Available Este artículo muestra resultados parciales del estudio relacionado con la religiosidad católica de los campesinos de los Andes Orientales colombianos, particularmente de las partes altas del Departamento de Boyacá. El tema central se organiza en torno al simbolismo de los santuarios donde se efectúan peregrinaciones y fiestas patronales que son elementos de construcción de identidad cultural y de memoria colectiva entre estas sociedades a nivel local y regional.Este artículo hace parte de la tesis doctoral, en la Universidad de Paris 8 en marzo de 2005.

Andes hantavirus variant in rodents, southern Amazon Basin, Peru.

Science.gov (United States)

Razuri, Hugo; Tokarz, Rafal; Ghersi, Bruno M; Salmon-Mulanovich, Gabriela; Guezala, M Claudia; Albujar, Christian; Mendoza, A Patricia; Tinoco, Yeny O; Cruz, Christopher; Silva, Maria; Vasquez, Alicia; Pacheco, Víctor; Ströher, Ute; Guerrero, Lisa Wiggleton; Cannon, Deborah; Nichol, Stuart T; Hirschberg, David L; Lipkin, W Ian; Bausch, Daniel G; Montgomery, Joel M

2014-02-01

We investigated hantaviruses in rodents in the southern Amazon Basin of Peru and identified an Andes virus variant from Neacomys spinosus mice. This finding extends the known range of this virus in South America and the range of recognized hantaviruses in Peru. Further studies of the epizoology of hantaviruses in this region are warranted.

Andes Hantavirus Variant in Rodents, Southern Amazon Basin, Peru

OpenAIRE

Razuri, Hugo; Tokarz, Rafal; Ghersi, Bruno M.; Salmon-Mulanovich, Gabriela; Guezala, M. Claudia; Albujar, Christian; Mendoza, A. Patricia; Tinoco, Yeny O.; Cruz, Christopher; Silva, Maria; Vasquez, Alicia; Pacheco, Víctor; Ströher, Ute; Guerrero, Lisa Wiggleton; Cannon, Deborah

2014-01-01

We investigated hantaviruses in rodents in the southern Amazon Basin of Peru and identified an Andes virus variant from Neacomys spinosus mice. This finding extends the known range of this virus in South America and the range of recognized hantaviruses in Peru. Further studies of the epizoology of hantaviruses in this region are warranted.

100 kyr fluvial cut-and-fill terrace cycles since the Middle Pleistocene in the southern Central Andes, NW Argentina

Science.gov (United States)

Tofelde, Stefanie; Schildgen, Taylor F.; Savi, Sara; Pingel, Heiko; Wickert, Andrew D.; Bookhagen, Bodo; Wittmann, Hella; Alonso, Ricardo N.; Cottle, John; Strecker, Manfred R.

2017-09-01

Fluvial fill terraces in intermontane basins are valuable geomorphic archives that can record tectonically and/or climatically driven changes of the Earth-surface process system. However, often the preservation of fill terrace sequences is incomplete and/or they may form far away from their source areas, complicating the identification of causal links between forcing mechanisms and landscape response, especially over multi-millennial timescales. The intermontane Toro Basin in the southern Central Andes exhibits at least five generations of fluvial terraces that have been sculpted into several-hundred-meter-thick Quaternary valley-fill conglomerates. New surface-exposure dating using nine cosmogenic 10Be depth profiles reveals the successive abandonment of these terraces with a 100 kyr cyclicity between 75 ± 7 and 487 ± 34 ka. Depositional ages of the conglomerates, determined by four 26Al/10Be burial samples and U-Pb zircon ages of three intercalated volcanic ash beds, range from 18 ± 141 to 936 ± 170 ka, indicating that there were multiple cut-and-fill episodes. Although the initial onset of aggradation at ∼1 Ma and the overall net incision since ca. 500 ka can be linked to tectonic processes at the narrow basin outlet, the superimposed 100 kyr cycles of aggradation and incision are best explained by eccentricity-driven climate change. Within these cycles, the onset of river incision can be correlated with global cold periods and enhanced humid phases recorded in paleoclimate archives on the adjacent Bolivian Altiplano, whereas deposition occurred mainly during more arid phases on the Altiplano and global interglacial periods. We suggest that enhanced runoff during global cold phases - due to increased regional precipitation rates, reduced evapotranspiration, or both - resulted in an increased sediment-transport capacity in the Toro Basin, which outweighed any possible increases in upstream sediment supply and thus triggered incision. Compared with two

Role of maca (Lepidium meyenii) consumption on serum interleukin-6 levels and health status in populations living in the Peruvian Central Andes over 4000 m of altitude.

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Gonzales, Gustavo F; Gasco, Manuel; Lozada-Requena, Ivan

2013-12-01

Lepidium meyenii (Maca) is a plant that grows at over 4,000 m above sea level in the central Peruvian Andes. The hypocotyls of this plant are traditionally consumed for their nutritional and medicinal properties. The aim of this study was to determine the health status based on a health related quality of life (HRQL) questionnaire (SF-20) and serum levels of interleukin 6 (IL-6) in subjects that are maca consumers. For this, a cross-sectional study was designed to be performed in 50 subjects from Junin (4,100 m): 27 subjects were maca consumers and 23 were non-consumers. The SF-20 survey is used to obtain a summary measure of health status. The stand up from a chair and sit down (SUCSD) test (to assess lower-extremity function), hemoglobin measurement, blood pressure, sexual hormone levels, serum IL-6 levels and the score of chronic mountain sickness (CMS) were evaluated. Testosterone/estradiol ratio (P maca consumers when compared to non-consumers (P maca consumers successfully completed the SUCSD test compared to non-consumers (P maca was associated with low serum IL-6 levels and in turn with better health status scores in the SF-20 survey and low chronic mountain sickness scores.

Redescripción y consideraciones biogeográfcas de dos especies de Scotobius (Coleoptera: Tenebrionidae de ambientes montanos del centro de Argentina y Chile Redescription and biogeographic considerations of two species of Scotobius (Coleoptera: Tenebrionidae from mountain environments of central Argentina and Chile

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Violeta A. Silvestro

2012-12-01

Full Text Available El género neotropical Scotobius Germar (Tenebrioninae: Scotobiini comprende 61 especies distribuidas desde el centro de Perú y sur de Brasil hasta el sur de Argentina y Chile. En este trabajo, revisamos dos especies de Scotobius que habitan el oeste de las provincias de San Juan, Mendoza y Neuquén (Argentina y en Chile central, a lo largo de la Cordillera de los Andes y las montañas extra-andinas en Argentina: S. punctatus Eschscholtz, 1831 y S. andrassyi Kaszab, 1969. Se proveen redescripciones utilizando nuevos caracteres morfológicos y se proporcionan fotografías de los adultos y de los pronotos. Se consigna la distribución geográfica, rangos altitudinales y las provincias biogeográficas en las que habitan estas especies. Se utiliza un modelo predictivo de distribución de especies para proponer hipótesis sobre los factores que influencian la distribución espacial y que explicarían la alopatría de ambas especies.The Neotropical genus Scotobius Germar (Tenebrioninae: Scotobiini comprises 61 species distributed from central Peru and southern Brazil to southern Argentine and Chile. In this contribution two species of Scotobius: S. punctatus Eschscholtz, 1831 and S. andrassyi Kaszab, 1969, that inhabit in western San Juan, Mendoza, and Neuquén provinces (Argentina and in central Chile, along the “Cordillera de los Andes” and extra-Andean mountains in Argentina, are revised. Redescriptions using new morphological data and photographs of habitus and pronota are provided. This article informs about the geographic distribution, altitudinal ranges and the biogeographic provinces that these species inhabit. A predictive model of species distribution is presented to propose hypothesis about the factors that influence the space distribution and the allopatry of these two species.

A new species of Trechisibus from Peruvian Andes (Coleoptera: Carabidae, Trechinae

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Pedro Delgado

2016-06-01

Full Text Available In this work the new species Trechisibus (s. str. delestali sp. n., is described from the southern Peruvian Andes. The morphological differences with the geographically closest species of the subgenus are also presented and discussed.

The Glaciation of the Ecuadorian Andes

Science.gov (United States)

Schubert, Carlos

This pleasing book fills the gap in the knowledge about Pleistocene and recent glaciation between Colombia and Peru. A significant amount of data exists already for Colombia and Venezuela and for Peru, Bolivia, and, particularly, Chile. Hastenrath has now given us a description of glaciers and glaciation underneath the equator in the Andes.The book begins with brief summaries of the physiography and the atmospheric circulation, which give the general setting of Ecuador. Then follow detailed descriptions of the glaciers and glacial morphology of all the important mountains of the Western and Eastern Cordilleras. These are well illustrated, and a particularly useful feature is the comparison of old photographs and paintings of glaciers with modern photographs, many taken by the author. All illustrate the spectacular retreat of the glaciers in the Ecuadorian Andes during the last century and correlate quite well with observations elsewhere. This retreat is snown quantitatively in Table 4, in terms of decrease in glacier-covered area since the glacial advance of moraine stage III. The area of present-day glaciers is about 10% of the area during that stage (compared with about 1.5% in the Sierra Nevada de Mérida, Venezuela). A series of maps show the glacial morphology of the mountains (unfortunately, some of the maps have been included within the binding, thus losing some information; they could have been reduced somewhat to fit a single page or, if too large, could have been included in the pocket, together with the map of Chimborazo-Carihuairazo).

Geología de los alrededores de los ríos caleufú y meliquina, provincia de Neuquén: El volcanismo de la Formación Huitrera

OpenAIRE

Palotti, Priscila F.; Jait, Damian M.; Orts, Darío Leandro; Litvak, Vanesa Dafne; Ramos, Victor Alberto

2017-01-01

En este trabajo se ha relevado la región localizada al sur de la Villa Meliquina, en la provincia del Neuquén, zona poco estudiada desde el punto de vista geológico. Esta se sitúa entre las localidades de San Martín de los Andes y San Carlos de Bariloche, donde afloran volcanitas aquí asignadas a la Formación Huitrera. En este sector se diferencian dos dominios con distintas características estructurales: un sector occidental, en la región del lago Filo Hua Hum, donde predominan plegamientos ...

El feto agresivo. Parto, formación de la persona y mito-historia en los Andes

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Platt, Tristan

2001-12-01

Full Text Available Partiendo de un estudio etnográfico y lingüístico sobre la mortalidad materna en Bolivia, este trabajo etno-obstétrico trata de la concepción, la gestación y el parto en una comunidad quechua-hablante de Potosí. Analiza el paralelismo planteado entre la formación temprana de la persona y los orígenes mito-históricos de la sociedad. La sustancia pagana pre-hispánica fluye constantemente hacia una sociedad de conversos, dando realidad al concepto jurídico de “indio originario”. Se propone superar la oposición entre las interpretaciones “esencialistas” e “hibridistas” de la sociedad indígena, al mostrar que el “originario” necesariamente se construye por los comuneros como “esencial”, pero sin por eso negar su constante transformación histórica. Los ritos de separación del “feto agresivo” de la madre también plantean preguntas a los psicoanalistas sobre la influencia que pueden tener las experiencias perinatales sobre la formación individual en diferentes contextos históricos y culturales.

The role of changing geodynamics in the progressive contamination of Late Cretaceous to Late Miocene arc magmas in the southern Central Andes

Science.gov (United States)

Jones, Rosemary E.; Kirstein, Linda A.; Kasemann, Simone A.; Litvak, Vanesa D.; Poma, Stella; Alonso, Ricardo N.; Hinton, Richard; EIMF

2016-10-01

The tectonic and geodynamic setting of the southern Central Andean convergent margin changed significantly between the Late Cretaceous and the Late Miocene, influencing magmatic activity and its geochemical composition. Here we investigate how these changes, which include changing slab-dip angle and convergence angles and rates, have influenced the contamination of the arc magmas with crustal material. Whole rock geochemical data for a suite of Late Cretaceous to Late Miocene arc rocks from the Pampean flat-slab segment (29-31 °S) of the southern Central Andes is presented alongside petrographic observations and high resolution age dating. In-situ U-Pb dating of magmatic zircon, combined with Ar-Ar dating of plagioclase, has led to an improved regional stratigraphy and provides an accurate temporal constraint for the geochemical data. A generally higher content of incompatible trace elements (e.g. Nb/Zr ratios from 0.019 to 0.083 and Nb/Yb from 1.5 to 16.4) is observed between the Late Cretaceous ( 72 Ma), when the southern Central Andean margin is suggested to have been in extension, and the Miocene when the thickness of the continental crust increased and the angle of the subducting Nazca plate shallowed. Trace and rare earth element compositions obtained for the Late Cretaceous to Late Eocene arc magmatic rocks from the Principal Cordillera of Chile, combined with a lack of zircon inheritance, suggest limited assimilation of the overlying continental crust by arc magmas derived from the mantle wedge. A general increase in incompatible, fluid-mobile/immobile (e.g., Ba/Nb) and fluid-immobile/immobile (e.g., Nb/Zr) trace element ratios is attributed to the influence of the subducting slab on the melt source region and/or the influx of asthenospheric mantle. The Late Oligocene ( 26 Ma) to Early Miocene ( 17 Ma), and Late Miocene ( 6 Ma) arc magmatic rocks present in the Frontal Cordillera show evidence for the bulk assimilation of the Permian-Triassic (P

Autoatención en Salud Oral en el Pueblo Yanacona de los Andes del Sur de Colombia

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Edson Jair Ospina Lozano

2011-07-01

Full Text Available Antecedentes. El pueblo indígena Yanacona tiene sus propias estrategias de entender y atender su proceso salud/enfermedad, referido particularmente a la cavidad oral. En estas actividades no se involucran terapeutas de la medicina tradicional ni de la medicina occidental, las realizan las mismas personas. Objetivo: identificar y analizar las prácticas de autoatención en salud oral de la población Yanacona de los resguardos de Caquiona y Pancitará. Materiales y métodos. Se utilizó el método etnográfico. Las técnicas fueron la entrevista semi-estructurada y la observación participante. La información se consignó en el diario de campo. El universo de trabajo fueron las familias de los resguardos de Pancitará y Caquiona. Las unidades de análisis las conformaron cinco familias que cumplían los criterios de inclusión: auto adscripción indígena, los ingresos económicos, la tenencia de dos o más hijos y la escolaridad de la madre.  Resultados: Para los integrantes de este pueblo indígena la boca es necesaria para comer y comunicarse. Las personas reconocen las enfermedades y otras dolencias en su cavidad oral y disponen de conocimientos y destrezas para enfrentarlas, principalmente plantas medicinales y medicamentos farmacéuticos. La caries dental es reconocida como la única enfermedad que afecta a la boca. Se reconoce un origen mágico de las aftas bucales. Los cuidados de la boca implican el uso de cepillo y crema dental y la masticación de una planta -chulco-. Conclusiones. La autoatención en salud oral es una estrategia que le permite a este pueblo indígena solucionar parcialmente los inconvenientes relacionados con su salud/enfermedad oral.

Autoatención en Salud Oral en el Pueblo Yanacona de los Andes del Sur de Colombia

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Edson Jair Ospina Lozano

2011-10-01

Full Text Available Antecedentes. El pueblo indígena Yanacona tiene sus propias estrategias de entender y atender su proceso salud/enfermedad, referido particularmente a la cavidad oral. En estas actividades no se involucran terapeutas de la medicina tradicional ni de la medicina occidental, las realizan las mismas personas. Objetivo: identificar y analizar las prácticas de autoatención en salud oral de la población Yanacona de los resguardos de Caquiona y Pancitará. Materiales y métodos. Se utilizó el método etnográfico. Las técnicas fueron la entrevista semi-estructurada y la observación participante. La información se consignó en el diario de campo. El universo de trabajo fueron las familias de los resguardos de Pancitará y Caquiona. Las unidades de análisis las conformaron cinco familias que cumplían los criterios de inclusión: auto adscripción indígena, los ingresos económicos, la tenencia de dos o más hijos y la escolaridad de la madre.  Resultados: Para los integrantes de este pueblo indígena la boca es necesaria para comer y comunicarse. Las personas reconocen las enfermedades y otras dolencias en su cavidad oral y disponen de conocimientos y destrezas para enfrentarlas, principalmente plantas medicinales y medicamentos farmacéuticos. La caries dental es reconocida como la única enfermedad que afecta a la boca. Se reconoce un origen mágico de las aftas bucales. Los cuidados de la boca implican el uso de cepillo y crema dental y la masticación de una planta -chulco-. Conclusiones. La autoatención en salud oral es una estrategia que le permite a este pueblo indígena solucionar parcialmente los inconvenientes relacionados con su salud/enfermedad oral.

Privatizing Water in the Chilean Andes: The Case of Las Vegas de Chiu-Chiu

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Manuel Prieto

2015-08-01

Full Text Available The Chilean water model has been described as a textbook example of a free-market water system. This article contributes to the critiques of this model by showing the effect of its implementation in the Atacameño community of Chiu-Chiu, located in the Atacama Desert in the south-central Andes. In this community, the privatization of water rights ignored local water management practices that had produced a high-altitude wetland (known as a vega. This led to the inhabitants’ dispossession of crucial water rights and to wetland degradation. This process belies statements that the Chilean model relies on an unregulated market and instead highlights the state’s role in marginalizing local irrigation practices by reducing the water consumption of the indigenous population while keeping the copper mining industry (the main source of Chilean income and related growing urban populations supplied with water.

Contribución al conocimiento de los Machiloidea de Colombia (Archaeognatha: Insecta Contribución al conocimiento de los Machiloidea de Colombia (Archaeognatha: Insecta

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Sturm Helmut

1983-09-01

Full Text Available Se describen cuatro nuevas especies y una subespecie de Meinertellidae recolectadas en Colombia y en un bosque pluvial cerca de Manaos, Brasil. Son las siguientes: Meinertellus adisi, M. bogotensis santaemartae, Neomachilellus aboucbaari, N. amazonicus y N. rangeli. Se discute la posición sistemática de los ejemplares recolectados cerca de Bogotá, en el valle del río Magdalena y en la Cordillera Oriental cerca de Neiva. Se da una clave para los géneros suramericanos de la familia.Four new species and one new subspecies of Meinertellidae occurring respectively in Colombia and in the rain forest near Manaus, Brazil, are described:  Meinertellus adisi, M. bogotensis santaemartae , Neomachilellus abouchaari, N. amazonicus and N. rangeli. The systematical position of specimens collected near Bogota, in the Magdalena Valley and in the Eastern Andes near Neiva is discussed. A key for the South American genera of the family is given.

Análisis de los factores que influyen en la aparición de complicaciones y supervivencia de los catéteres venosos centrales para hemodiálisis

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Gabriel Eduardo Rajoy Fernández

2014-03-01

Full Text Available Una de las principales actividades de enfermería nefrológica en las unidades de hemodiálisis, es el cuidado de catéteres venosos centrales mediante el cumplimiento de un protocolo que hace especial hincapié en las medidas universales de asepsia durante su manipulación. Además existen otras variables que pueden influir en la aparición de complicaciones del catéter limitando su supervivencia. Objetivo: Los objetivos de este estudio fueron analizar los factores que pudieran influir en la aparición de complicaciones del catéter venoso central para hemodiálisis, y valorar las tasas de infección en nuestro centro. Material y método: Se realizó un estudio descriptivo de una cohorte, en la Unidad de Diálisis del Hospital Meixoeiro, entre enero de 1991 y octubre de 2012, con una muestra formada por 1231 catéteres. Resultados: Fueron implantados 1231 catéteres (1187 temporales y 44 tunelizados tipo Hikman. Los temporales, 78% en femoral, 18% en yugular, y 4 % en subclavia. Los Hikman, 40 en lado derecho y 4 en lado izquierdo. La duración media de los catéteres implantados fue de 17,7 ± 30,8 días (mediana 8 días. 88% no presentaron incidencias durante su colocación. Las principales causas de colocación fueron la IRA (56% y el fallo de acceso vascular previo (30%. La principal complicación dentro de las causas de retirada fue la obstrucción del catéter (15%, siendo la más grave la infección (6%. De los 1231 catéteres, 70 presentaron un episodio de infección a los 19,1±33,0 días de media, (mediana 1 días. Tasa de infección (2010-2012 de 0,75/1000 días de catéter. Conclusión: Concluimos que la aplicación de cuidados continuos y estandarizados mediante un protocolo que hace especial hincapié en la asepsia durante la conexión y desconexión del CVC da como resultado un bajo índice de infecciones en esta unidad.

An elusive new species of Marsupial Frog (Anura: Hemiphractidae: Gastrotheca from the Andes of northern Peru

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William E. Duellman

2013-06-01

Full Text Available A new species of marsupial frog, genus Gastrotheca, is described from high-elevation grasslands in the Andes in Región Amazonas in northernPeru, where even calling males are well hidden in deep moss. The new species is distinguished from all congeners by its unique color pattern that includes a narrow, blackbordered, yellow middorsal stripe. The species apparently belongs to the Gastrotheca plumbea Group, which ranges in the Andes from northern Colombia to northern Peru.

The volcanism of the western part of the Los Frailes Meseta (Bolivia): a representative example of the Andean volcanism since the Upper Oligocene; Le volcanisme de la bordure occidentale de la Meseta de Los Frailes (Bolivie): un jalon representatif du volcanisme andin depuis l`Oligocene superieur

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Leroy, L. [Nancy-1 Univ., 54 (France); Jimenez, N.

1996-12-31

The Los Frailes Meseta (Bolivia) is one of the large tertiary ignimbritic fields of the inner volcanic arc from Central Andes (Central Volcanic Zone. CVZ), in contact zone between the Altiplano to the west and the Eastern Cordillera to the east. Field observations and mineralogical and geochemical studies (major and trace elements) lead to distinguish two types of volcanism in the western border to the Meseta. During the Middle Miocene and Pliocene, the volcanic activity can be subdivided into three pyroclastic emission cycles, the Larco, Coroma and Pliocene ignimbrites, the first two being separated by the Quechua 2 orogeny. All these ignimbrites are very similar and correspond to peraluminous rhyolites to rhyodacites. In the studies area, the Coroma cycle is the only one where an ignimbrite-less evolved resurgent dome association can be observed. Beside these ignimbrites, isolated small lava flows and domes overlay and/or intrude all the other formations. They are meta-aluminous lavas with a shoshonitic affinity. A quaternary age can be attributed to his second volcanism. These two volcanic types are well-known in the CVZ and are related to the different deformation stages, either compressional or extensional, which occur alternately in the Cordillera since 26 Ma. (authors). 61 refs., 12 figs., 3 tabs.

Craniofacial chronological microdifferentiation of human prehistoric populations of the Azapa valley, northern Chile Microdiferenciación cronológica craneofacial de poblaciones humanas prehistóricas del Valle de Azapa, norte de Chile

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FRANCISCO ROTHHAMMER

2002-03-01

Full Text Available Archeological evidence suggest that the cultural developments occurred in the highlands around lake Titicaca in the Central Andes, exerted influence on the cultural elaborations of the human groups that peopled the valley of Azapa, close to the city of Arica, and the Pacific coast of northern Chile. In this communication we show by means of a distance analysis, that a craniofacial differentiation accompanied the process of cultural evolution in the valley. The biological influence of Tiwanaku is partially reflected in craniofacial morphology, providing preliminary evidence that cultural changes were associated to intermittent gene flow from the highlands, specially during the Alto Ramírez and San Miguel phasesLos desarrollos culturales ocurridos en el altiplano en el área circumtiticaca en los Andes centrales, ejercieron influencia sobre las elaboraciones culturales de los grupos humanos que poblaban el Valle de Azapa cercano a la ciudad de Arica y la costa del norte de Chile. En esta comunicación presentamos un análisis de distancias que demostró que una diferenciación craniofacial acompaño en el valle el proceso de evolución cultural. La influencia biológica de Tiwanaku se refleja parcialmente en la morfología craniofacial, proporcionando evidencia preliminar de que los cambios culturales en el valle se realizaron acompañados de flujo génico intermitente desde el altiplano, especialmente durante las fases Alto Ramírez y San Miguel

Caries dental en niños de 0-5 años del municipio de Andes, Colombia. Evaluación mediante el sistema internacional de detección y valoración de caries - ICDAS

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Blanca S. Ramírez-Puerta

2017-01-01

Full Text Available La falta de información de la situación de caries dental en la primera infancia en Andes, limita las acciones en el marco de la Alianza por un Futuro libre de Caries. Objetivo: establecer la situación de caries dental de los niños y niñas de 0 a 5 años del Municipio de Andes, Colombia. Metodología: fueron examinados 623 niños y niñas para evaluar la presencia y severidad de las lesiones de caries, con base en criterios del Sistema Internacional para la detección y evaluación de caries - icdas. Se calcularon las proporciones de experiencia y prevalencia de caries dental, y los índices cICDAS 5-6 opd y cICDAS 1-6 opd. Resultados: el 38,2% tenía experiencia de caries dental severa, cuando se incluyen las lesiones iniciales y moderadas de caries dental la experiencia fue 88,4%. Al año de edad, el 4,9% tenía lesiones severas de caries dental, y a los 5 años el 53,6% presentó este tipo de lesiones. El índice cICDAS 5-6 opd fue 0,15±0,8 al año de edad y 2,79±3,6 a los 5 años; el valor del indicador aumenta a 1,97±2,9 y 9,61±4,6 respectivamente, cuando se incluyen lesiones iniciales y moderadas de caries dental, cICDAS 1-6 opd. Discusión: la enfermedad está presente desde el primer año en el 58,8%, el doble de lo reportado en el país a esta edad (29,3%. Conclusión: los hallazgos resaltan la necesidad de diseñar estrategias integrales para el control de la enfermedad, que involucren la salud bucal en políticas y programas de primera infancia.

Different Phases of Earthquake Cycle Reflected in GPS Measured Crustal Deformations along the Andes

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Khazaradze, G.; Klotz, J.

2001-12-01

The South American Geodynamic Activities (SAGA) project was initiated in 1993 by the GeoForschungsZentrum together with host organizations in Argentina and Chile with the main objective of studying the kinematics and dynamics of present-day deformation processes along the central and southern Andes. Currently the SAGA network consists of 230 geodetic markers spanning more than 2000 km long distance from Peru/Chile border in the north to Cape Horn in the south. The majority of the observed crustal deformation field is relatively homogenous: roughly parallel to the plate convergence direction and decreasing in magnitude away from the deformation front. This pattern is characteristic for the \\textit{inter-seismic} phase of earthquake deformation cycle and can be explained by the elastic strain accumulation due to locking of the thrust interface between the subducting Nazca and the overriding South America plates. However, in addition to the dominant inter-seismic signal, close examination of the observed velocity field also reveals significant spatial and temporal variations, contrary to the commonly used assumption of constant deformation rates. This variation is especially pronounced for the measurements in the vicinity of the 1995 Mw8.0 Antofagasta earthquake (22{° }S-26{° }S). Here, after capturing up to 1 meters of \\textit{co-seismic} displacements associated with this event, the analysis of data obtained during the three following field campaigns (1996-1999), reveals highly time dependent deformation pattern. This can be explained by the decreasing importance of \\textit{post-seismic} effects of the Antofagasta event relative to the increasing dominance of the inter-seismic phase of subduction. Perhaps, even more interesting time dependent observations have been detected in the southern part the SAGA network (38{° }S-43{° }S).Here, after 35 years of the occurrence of the 1960 Mw9.5 Chile earthquake, we still see the continuing post-seismic effects of this

A high-altitude peatland record of environmental changes in the NW Argentine Andes (24 ° S) over the last 2100 years

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Schittek, Karsten; Kock, Sebastian T.; Lücke, Andreas; Hense, Jonathan; Ohlendorf, Christian; Kulemeyer, Julio J.; Lupo, Liliana C.; Schäbitz, Frank

2016-05-01

High-altitude cushion peatlands are versatile archives for high-resolution palaeoenvironmental studies, due to their high accumulation rates, range of proxies, and sensitivity to climatic and/or human-induced changes. Especially within the Central Andes, the knowledge about climate conditions during the Holocene is limited. In this study, we present the environmental and climatic history for the last 2100 years of Cerro Tuzgle peatland (CTP), located in the dry Puna of NW Argentina, based on a multi-proxy approach. X-ray fluorescence (XRF), stable isotope and element content analyses (δ13C, δ15N, TN and TOC) were conducted to analyse the inorganic geochemistry throughout the sequence, revealing changes in the peatlands' past redox conditions. Pollen assemblages give an insight into substantial environmental changes on a regional scale. The palaeoclimate varied significantly during the last 2100 years. The results reflect prominent late Holocene climate anomalies and provide evidence that in situ moisture changes were coupled to the migration of the Intertropical Convergence Zone (ITCZ). A period of sustained dry conditions prevailed from around 150 BC to around AD 150. A more humid phase dominated between AD 200 and AD 550. Afterwards, the climate was characterised by changes between drier and wetter conditions, with droughts at around AD 650-800 and AD 1000-1100. Volcanic forcing at the beginning of the 19th century (1815 Tambora eruption) seems to have had an impact on climatic settings in the Central Andes. In the past, the peatland recovered from climatic perturbations. Today, CTP is heavily degraded by human interventions, and the peat deposit is becoming increasingly susceptible to erosion and incision.

Trauma and violence in the Wari empire of the Peruvian Andes: warfare, raids, and ritual fights.

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Tung, Tiffiny A

2007-07-01

This study examines bioarchaeological evidence for violence during the period of Wari imperialism in the Peruvian Andes through analysis of skeletal trauma from three populations dating to AD 650-800. The samples are from contemporaneous archaeological sites: Conchopata, a Wari heartland site in central highland Peru; Beringa, a community of commoners in the Majes valley of the southern Wari hinterland; and La Real, a high status mortuary site, also in the Majes valley. Given the expansionist nature of Wari and its military-related iconography and weaponry, it is hypothesized that Wari imperialism was concomitant with greater levels of violence relative to other prehispanic groups in the Andes. It is also hypothesized that differential articulation with the Wari empire (e.g., heartland vs. hinterland groups) affected the frequency and patterning of trauma. Results show that cranial trauma frequency of the three Wari era samples is significantly greater than several other Andean skeletal populations. This suggests that Wari rule was associated with high levels of violence, though it may not have always been related to militarism. The three adult samples show similar frequencies of cranial trauma (Conchopata = 26%; Beringa = 33%; La Real = 31%). This may suggest that differential positioning in the Wari empire had little effect on exposure to violence. Sex-based differences in cranial trauma frequencies are present only at La Real, but wound patterning differs between the sexes: females display more wounds on the posterior of the cranium, while males show more on the anterior. These data suggest that Wari rule may have contributed to violence. (c) 2007 Wiley-Liss, Inc.

A survey of volcano deformation in the central Andes using InSAR: Evidence for deep, slow inflation

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Pritchard, M. E.; Simons, M.

2001-12-01

We use interferometric synthetic aperture radar (InSAR) to survey about 50 volcanos of the central Andes (15-27o S) for deformation during the 1992-2000 time interval. Because of the remote location of these volcanos, the activity of most are poorly constrained. Using the ERS-1/2 C-band radars (5.6 cm), we observe good interferometric correlation south of about 21o S, but poor correlation north of that latitude, especially in southern Peru. This variation is presumably related to regional climate variations. Our survey reveals broad (10's of km), roughly axisymmetric deformation at 2 volcanic centers with no previously documented deformation. At Uturuncu volcano, in southwestern Bolivia, the deformation rate can be constrained with radar data from several satellite tracks and is about 1 cm/year between 1992 and 2000. We find a second source of volcanic deformation located between Lastarria and Cordon del Azufre volcanos near the Chile/Argentina border. There is less radar data to constrain the deformation in this area, but the rate is also about 1 cm/yr between 1996 and 2000. While the spatial character of the deformation field appears to be affected by atmosphere at both locations, we do not think that the entire signal is atmospheric, because the signal is observed in several interferograms and nearby edifices do not show similar patterns. The deformation signal appears to be time-variable, although it is difficult to determine whether this is due to real variations in the deformation source or atmospheric effects. We model the deformation with both a uniform point-source source of inflation, and a tri-axial point-source ellipsoid, and compare both elastic half-space and layered-space models. We also explore the effects of local topography upon the deformation field using the method of Williams and Wadge (1998). We invert for source parameters using the global search Neighborhood Algorithm of Sambridge (1998). Preliminary results indicate that the sources at both

Efectos del clodimeformo sobre el desarrollo de los sistemas de neurotransmisores monoaminérgicos en el sistema nervioso central de rata

OpenAIRE

García Sánchez, José Manuel

2016-01-01

Se ha descrito para algunos compuestos formamidínicos la inducción de alteraciones permanentes sobre el desarrollo del sistema nervioso central tales como perturbaciones permanentes sobre los sistemas de neurotransmisores monoaminérgicos, para los cuales se ha sugerido como posible mecanismo la inhibición de la monoamino oxidasa (MAO), no pudiéndose descartar otros mecanismos como la disrrupcion endocrina de hormonas sexuales las cuales controlan la expresión de las enzimas que catalizan la s...

Los dioses de los tejidos de Paracas (Perú)

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Castro Paredes, Celia

2017-01-01

La cultura de Paracas, tiene un papel central en la prehistoria andina. Su importancia se puede deducir de los ricos ajuares de sus múltiples fardos funerarios. En estos se han encontrado múltiples y maravillosos mantos, junto a otros objetos que acompañaban a las momias de los difuntos principales. Sin embargo, hay cuestiones todavía no bien conocidas, como su origen y final, y sobre todo el papel de los excepcionales tejidos, cuyos dibujos y figuras son un enigma que podría relacionarse o i...

MARIPOSAS PIERIDAE (LEPIDOPTERA: PAPILIONOIDEA) DE LA CUENCA DEL RÍO COELLO (TOLIMA), COLOMBIA

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Ospina-López, Leonardo A.; García-Pérez, Jack F.; Villa-Navarro, Francisco A.; Reinoso-Flórez, Gladys

2010-01-01

Este estudio analiza la composición, riqueza, diversidad y estructura de la familia Pieridae en la cuenca del río Coello, cordillera Central de los Andes, departamento de Tolima (Colombia). Se establecieron 11 estaciones de muestreo localizadas entre los 433 y 3.600 m de altitud, que fueron muestreadas entre marzo y octubre de 2003, teniendo en cuenta tres tipos de hábitat (pradera, borde y bosque), mediante transectos de longitud no definida, entre las 08:00 y las 16:00 h, empleando para ell...

BIOLOGÍA REPRODUCTIVA DE UNA POBLACIÓN DE ANOLIS TOLIMENSIS (SAURIA: IGUANIDAE EN LOS ANDES COLOMBIANOS

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ARDILA-MARÍN DANIEL ALEXANDER

2008-07-01

Full Text Available Estudiamos algunas características morfométricas y el estado reproductivo deespecímenes de ambos sexos de Anolis tolimensis en una población de los Andescolombianos (Tena, Cundinamarca; 2250 m. Las observaciones se hicieron en unbosque secundario, entre las épocas de lluvia (noviembre 2004 y febrero 2005 y desequía (diciembre 2004 - enero 2005. En el campo realizamos recorridos diurnosentre las 8:00 y 18:00 horas y recolectamos individuos de forma manual y con lazada.En el laboratorio medimos los individuos y determinamos el estado reproductivo.Las hembras adultas y juveniles presentaron mayor longitud rostro-cloacal que losmachos. El tamaño mínimo promedio de madurez sexual en machos fue 43.7 mmy en hembras 46.4 mm. El estado reproductivo más común en hembras adultas fuevitelogénico y ovígero, el menos frecuente fue ovígero con dos huevos oviductales.Esta condición de ovo-retención podría relacionarse con condiciones ambientalesdesfavorables. No se encontraron hembras adultas en estado previtelogénico. Hubopresencia generalizada de un huevo oviductal. Entre los periodos de muestreose encontró que los machos fueron sexualmente activos y observamos presenciageneralizada de hembras embarazadas o con huevos oviductales. Estas observacionesindicarían reproducción continua de A. tolimensis a lo largo del año

BURMEISTERA DIAZII(CAMPANULACEAE: LOBELIOIDEAE, UNA ESPECIE NUEVA DE LOS ANDES DE ANTIOQUIA, Y NOTAS ACERCA DEL NUEVO REGISTRO DE B. LOEJTNANTII PARA COLOMBIA

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JAVIER GARZÓN VENEGAS

2014-12-01

Full Text Available Burmeistera diazii (Campanulaceae: Lobelioideae, de la Cordillera Central de Colombia, en la franja altitudinal entre 1,800 y 2,750 m en los municipios de Sonsón y Guatapé (Antioquia, es descrita como una especie nueva. Se discuten en detalle las semejanzas morfológicas con sus especies afines (B. obtusifolia, de Costa Rica y Panamá, B. killipii y B. serraniaguae, de Colombia y B. crassifolia y B. loejtnantii, de Colombia y Ecuador, las cuales se caracterizan por tener hojas ovadas a ovado-lanceoladas, pedúnculo ebracteado y lóbulos del cáliz largos. Se registra B. loejtnantii por primera vez para la flora de Colombia.

Genetic continuity after the collapse of the Wari empire: mitochondrial DNA profiles from Wari and post-Wari populations in the ancient Andes.

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Kemp, Brian M; Tung, Tiffiny A; Summar, Marshall L

2009-09-01

The Wari empire flourished in the central, highland Peruvian Andes from AD 600-1000, and although the events that led to its demise are unknown, archaeological evidence indicates that Wari control waned at the end of the first millennium. Here, we test the hypothesis that, despite the major shift in social and political organization at the fall of the Wari empire, the mitochondrial DNA (mtDNA) composition of populations from the Ayacucho Basin, the former imperial heartland of the empire, remained essentially unchanged. Results show that mtDNA haplogroup frequencies among the Wari and post-Wari groups differ, but the difference is not statistically significant (chi2 = 5.886, df = 3, P = 0.1172). This is the first study in the Andes to use haplotypic data to evaluate the observed genetic distance between two temporally distinct prehispanic populations (F(ST) = 0.029) against modeled expectations of four possible evolutionary scenarios. None of these simulations allowed the rejection of continuity. In total, at both the haplogroup and haplotype levels these data do not allow us to reject the hypothesis that post-Wari individuals sampled in this study are the maternal descendants of those sampled from the Wari era site of Conchopata. However, genetic homogeneity in the mitochondrial gene pool, as seen in the late prehispanic southern Andes, may also characterize our study region. But, prior to this research, this was unknown. If our new data show mtDNA homogeneity, then this could limit the detection of female migration if, in fact, it occurred. Nonetheless, the novel mtDNA data presented here currently do not support the hypothesis that there was an influx of genetically distinct females into the former Wari heartland after the Wari collapse. Copyright 2009 Wiley-Liss, Inc.

Within plate seismicity analysis in the segment between the high Cordillera and the Precordillera of northern Mendoza (Southern Central Andes

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Julián Olivar

2018-01-01

Full Text Available Crustal seismicity in northwestern Mendoza Province in Argentina, corresponding to the transition zone between the Chilean-Pampean flat subduction zone (26.5–33.5°S and the Southern Central Andes normal subduction zone to the south, is studied in order to i identify its relationship with the mapped structure, ii determine deformational mechanisms and iii constrain the geometry of the fold and thrust belt in the lower crust. Through this, we aim to determine which are the structures that contribute to Andean construction, east of the Frontal Cordillera in Argentina and at the western Principal Cordillera in Chile. Data from a temporary local seismic network are reprocessed in order to achieve a precise location of hypocenters and, whenever possible, to build focal mechanisms. Results are interpreted and compared with previous seismic studies and structural models. Analyzed seismicity is grouped around the eastern front of Frontal Cordillera, with hypocenters mainly at depths of 25–40 km. Contrastingly, earthquakes in the Principal Cordillera to the west are located at the axial Andean sector and Chilean slope, with depths shallower than 15 km. Obtained focal mechanisms indicate mainly strike-slip displacements, left lateral at Frontal Cordillera and right lateral at Principal Cordillera. Based on these observations, new possible structural models are proposed, where seismogenic sources could be either associated with inherited basement structures from the Cuyania-Chilenia suture; or correspond to deep-blind thrusts linked with a deeper-than-previously-assumed decollement that could be shared between Frontal Cordillera and western Precordillera. This deeper decollement would coincide in turn with the one determined from receiver function analysis for the eastern Sierras Pampeanas in previous works, potentially implying a common decollement all through the fold and thrust belt configuration. Apart from this, a new interpretation of

A review of the albidohirta group of Ptilothrix (Hymenoptera: Apidae: Emphorini Revisión del grupo albidohirta de Ptilothrix (Hymenoptera: Apidae: Emphorini

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Arturo Roig Alsina

2007-12-01

Full Text Available The albidohirta group of Ptilothrix Smith includes three species: Ptilothrix albidohirta Brèthes, P. concolor sp. nov., and P. nemoralis sp. nov. The group is known from northern and western Argentina and from central Bolivia. One of its species, P. albidohirta, reaches high altitudes in the Andes mountains, up to 3600 m a.s.l., while the other two species occur in the lowlands. A characterization of the group, descriptions of the species, and illustrations are provided.El grupo albidohirta de Ptilothrix Smith incluye tres especies: Ptilothrix albidohirta Brèthes, P. concolor sp. nov. y P. nemoralis sp. nov. Este grupo se conoce del oeste y norte de la Argentina y del centro de Bolivia. Una de sus especies, P. albidohirta, llega hasta los 3.600 m s.n.m. en la cordillera de los Andes, en tanto que las otras dos especies habitan en el llano. Se caracteriza el grupo y se describen e ilustran las especies.

Holocene tephra-fall deposits of southern and austral Andes volcanic zones (33-54oS): eruption recurrence

International Nuclear Information System (INIS)

Naranjo, J.A.; Polanco, E.; Lara, L; Moreno, H; Stern, C.R

2001-01-01

Radiometric 14 C dating is a very useful tool to study the chronostratigraphy of pyroclastic deposits. In addition, 14 C ages are essential parameters for the estimation of the recurrence time of the explosive volcanic activity. The origin, distribution and relative age of mappable Holocene tephra-fall deposits of the Southern Andes Volcanic Zone (SVZ) and Austral Andes Volcanic Zone (AVZ) from 33 o S-54 o S, were studied and their recurrence period is analysed (au)

Distribución y conservación de especies amenazadas en Mesoamérica, Chocó y Andes tropicales Distribution and conservation of endangered species in Mesoamerica, Chocó and Tropical Andes

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María Cecilia Londoño-Murcia

2011-09-01

Full Text Available En este estudio se modeló el nicho ecológico proyectado como distribución potencial de 313 especies amenazadas en Mesoamérica, Chocó y los Andes tropicales, según las listas de la UICN. De estas especies, 285 fueron plantas y 28 fueron vertebrados terrestres. La superposición de las distribuciones de las especies amenazadas cubrió prácticamente toda la región. Ecuador mostró cerca del 30% de su área con 50 especies. Colombia, Costa Rica, Guatemala, Nicaragua y Panamá mostraron > 50, aunque en 50% de su área. El Salvador y Honduras, de 11 a 20 en > 50% de su área y México de 1 a 5 especies en > 50% de su área. La distribución de estas especies en áreas transformadas (agricultura y áreas urbanas varió del 11al 30%; El Salvador, Panamá y Guatemala mostraron > 50% de la distribución; Colombia, Honduras y México This study modeled ecological niches projected as potential distributions for 313 endangered species listed in the IUCN for Mesoamerica, Chocó and Tropical Andes, of which 285 were plants, and 28 terrestrial vertebrates. Overlapping of endangered species distributions covered most of the region. Ecuador showed close to 30% of its area with 50 endangered species. Colombia, Costa Rica, Guatemala, Nicaragua y Panama showed more than 50 endangered species in 50% of its area with endangered species (21 to 50 species were Costa Rica, Ecuador, Nicaragua and Panama. El Salvador and Honduras showed > 50% of its area with 11 to 20 endangered species; Mexico showed 50% of endangered species in transformed areas; Colombia, Honduras and Mexico showed < 40%, and Belize and Ecuador showed < 25% of endangered species in transformed areas, respectively. El Salvador, Honduras, Panama, Nicaragua and Mexico showed a high proportion of endangered species in transformed areas for the Classes Amphibia, Liliopsida, Polipodiopsida, and the Orders Asterales, Fabales, Laurales, Myrtales, Scrophulariales and Rubiales. Less than 35% of endangered

Late Pleistocene glaciations of the arid subtropical Andes and new results from the Chajnantor Plateau, northern Chile

Science.gov (United States)

Ward, Dylan J.; Cesta, Jason M.; Galewsky, Joseph; Sagredo, Esteban

2015-11-01

The spatiotemporal pattern of glaciation along the Andes Mountains is an important proxy record reflecting the varying influence of global and regional circulation features on South American climate. However, the timing and extent of glaciation in key parts of the orogen, particularly the deglaciated arid Andes, are poorly constrained. We present new cosmogenic 10Be and 36Cl exposure ages for glacial features on and near the Chajnantor Plateau (23 °S). The new dates, although scattered due to cosmogenic inheritance, imply that the most recent extensive glacial occupation ended before or during the global Last Glacial Maximum (LGM). We discuss this new record in the context of published glacial chronologies from glacial features in Peru, Bolivia, and northern Chile rescaled using the latest cosmogenic 10Be production rate calibration for the tropical Andes. The results imply regionally synchronous moraine stabilization ca. 25-40 ka, 15-17 ka, and 12-14 ka, with the youngest of these moraines absent in records south of ∼20 °S, including in our new Chajnantor area chronology. This spatial pattern implicates easterly moisture in generating sufficient snowfall to glaciate the driest parts of the Andes, while allowing a role for westerly moisture, possibly modulated by the migration of the Southern Westerly Wind belt, in the regions near and south of the Atacama Desert.

On the extension of the analytic nodal diffusion solver ANDES to sodium fast reactors

International Nuclear Information System (INIS)

Ochoa, R.; Herrero, J.J.; Garcia-Herranz, N.

2011-01-01

Within the framework of the Collaborative Project for a European Sodium Fast Reactor, the reactor physics group at UPM is working on the extension of its in-house multi-scale advanced deterministic code COBAYA3 to Sodium Fast Reactors (SFR). COBAYA3 is a 3D multigroup neutron kinetics diffusion code that can be used either as a pin-by-pin code or as a stand-alone nodal code by using the analytic nodal diffusion solver ANDES. It is coupled with thermal-hydraulics codes such as COBRA-TF and FLICA, allowing transient analysis of LWR at both fine-mesh and coarse-mesh scales. In order to enable also 3D pin-by-pin and nodal coupled NK-TH simulations of SFR, different developments are in progress. This paper presents the first steps towards the application of COBAYA3 to this type of reactors. ANDES solver, already extended to triangular-Z geometry, has been applied to fast reactor steady-state calculations. The required cross section libraries were generated with ERANOS code for several configurations. Here some of the limitations encountered when attempting to apply the Analytical Coarse Mesh Finite Difference (ACMFD) method - implemented inside ANDES - to fast reactor calculations are discussed and the sensitivity of the method to the energy-group structure is studied. In order to reinforce some of the conclusions obtained two calculations are presented. The first one involves a 3D mini-core model in 33 groups, where the ANDES solver presents several issues. And secondly, a benchmark from the NEA for a small 3D FBR in hexagonal-Z geometry in 4 energy groups is used to verify the good convergence of the code in a few-energy-group structure. (author)

The volcanism of the western part of the Los Frailes Meseta (Bolivia): a representative example of the Andean volcanism since the Upper Oligocene

International Nuclear Information System (INIS)

Leroy, L.; Jimenez, N.

1996-01-01

The Los Frailes Meseta (Bolivia) is one of the large tertiary ignimbritic fields of the inner volcanic arc from Central Andes (Central Volcanic Zone. CVZ), in contact zone between the Altiplano to the west and the Eastern Cordillera to the east. Field observations and mineralogical and geochemical studies (major and trace elements) lead to distinguish two types of volcanism in the western border to the Meseta. During the Middle Miocene and Pliocene, the volcanic activity can be subdivided into three pyroclastic emission cycles, the Larco, Coroma and Pliocene ignimbrites, the first two being separated by the Quechua 2 orogeny. All these ignimbrites are very similar and correspond to peraluminous rhyolites to rhyodacites. In the studies area, the Coroma cycle is the only one where an ignimbrite-less evolved resurgent dome association can be observed. Beside these ignimbrites, isolated small lava flows and domes overlay and/or intrude all the other formations. They are meta-aluminous lavas with a shoshonitic affinity. A quaternary age can be attributed to his second volcanism. These two volcanic types are well-known in the CVZ and are related to the different deformation stages, either compressional or extensional, which occur alternately in the Cordillera since 26 Ma. (authors). 61 refs., 12 figs., 3 tabs

LOS CENTROS DE DESARROLLO CIENTÍFICO Y HUMANÍSTICO: REALIDAD O UTOPÍA CASO: ULA, LUZ, UNEFM

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Mercedes Carrasquero

1999-07-01

Full Text Available Este artículo presenta un estudio sobre la característica y particularidades de los centros de desarrollo científicos y humanístico (CDCH de la Universidad de los Andes, Universidad del Zulia y la Universidad Nacional Experimental "francisco de Mirando". Dado que la universidad es la casa de la sociedad, tiene el deber insoluble de participar en el desarrollo económico, social, cultural, político y tecnológico nacional y regional. De allí urge la necesidad de visualizar dentro de un escenario que promocione la actividad científica y académica articulada a las exigencias y requerimientos de la sociedad. Por eso se impone una revisión de las condiciones actuales e inmediatas futuras de los CDCH a objeto de potenciar sus fortalezas y oportunidades y atender con prontitud sus debilidades y amenazas.

Interpreting compositional zonation of the Zaragoza ignimbrite from Los Humeros caldera, Central Mexico

International Nuclear Information System (INIS)

Carrasco-Nunez, Gerardo; McCurry, Michael; Branney, Michael J

2008-01-01

Compositional zonation in ignimbrites is relatively common, and is often inferred to record gradual withdrawal by an eruption of a density-stratified magma chamber (with silicic magma towards the top and more dense, mafic magma at the bottom). We show that this model does not match observations at the ca. 0.1 Ma Zaragoza ignimbrite from Los Humeros caldera in central Mexico. Detailed petrologic studies reveal a more complex scenario: the ignimbrite exhibits a 'double' vertical zonation based on the compositions of pumice lapilli. We present evidence for mingling and limited mixing occurred during or immediately before the caldera-forming eruption. One possibility to explain the observations is that the ignimbrite eruption occurred in response to intrusion of a hybridized andesitic magma into a rhyodacitic magma chamber.

The forest vegetation of Ramal de Guaramacal in the Venezuelan Andes

NARCIS (Netherlands)

Cuello, A.N.L.; Cleef, A.M.

2009-01-01

Montane forest community composition of Ranial de Guaramacal, Venezuelan Andes, was studied along the altitudinal gradient on both sides of the range with different slope expositions. Thirty five 0.1 ha plots were Surveyed, with variable intervals of 30 to 150 meters between 1350 in and 2890 in and

The forest vegetation of Ramal de Guaramacal in the Venezuelan Andes

NARCIS (Netherlands)

Cuello A., N.L.; Cleef, A.M.

2009-01-01

Montane forest community composition of Ramal de Guaramacal, Venezuelan Andes, was studied along the altitudinal gradient on both sides of the range with different slope expositions. Thirty five 0.1 ha plots were surveyed, with variable intervals of 30 to 150 meters between 1350 m and 2890 m and

Tumor sólido pseudopapilar de páncreas. Presentación de un caso reportado en Hospital Universitario de Los Andes, Mérida-Venezuela

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Naisbet Ortega-Vásquez

2013-05-01

Full Text Available El tumor sólido pseudopapilar de páncreas es una neoplasia de bajo grado de malignidad, de etiología incierta y relativamente raro con una incidencia de 0.2 a 2.7% entre los tumores de páncreas exocrino. Se presenta con mayor frecuencia en mujeres jóvenes, siendo muy raro en varones, y existen pocos casos de mortalidad asociados a éste tumor. Pueden encontrarse incidentalmente o dar síntomas abdominales inespecíficos. Presentamos el caso de paciente femenina de 16 años de edad, quien consultó por saciedad temprana y dolor abdominal tipo cólico en epigastrio e hipocondrio derecho. Se realizó endoscopia digestiva superior punción con aguja guiada (PAF guiada por ultrasonido endoscópico de lesión quística en cola de páncreas, con hallazgos compatibles con tumor sólido pseudopapilar de páncreas. Se realizó Pancreatectomía córporo-caudal con estudio de biopsia, los cuales confirmaron el diagnóstico preoperatorio. El tumor sólido pseudopapilar pancreático incluye entre sus manifestaciones clínicas dolor abdominal, sensación de plenitud o saciedad temprana, masa abdominal, náuseas y vómitos, entre otras. La tomografía axial computarizada puede revelar masa heterogénea grande y encapsulada. El diagnóstico definitivo se realiza con el estudio histopatológico y el tratamiento de elección es la cirugía, la cual por sí sola tiene un nivel elevado de curación. Solid-pseudopapillary tumor of the pancreas. A report in the Hospital Universitario de Los Andes, Mérida-Venezuela Abstract Solid pseudopapillary tumor of the pancreas is a neoplasm of low malignant, of uncertain etiology and relatively rare with an incidence of 0.2 to 2.7% between exocrine pancreatic tumors. It occurs most often in young women and is very rare in men, and there are few cases of mortality associated with this tumor. May be found incidentally or give nonspecific abdominal symptoms. We report the case of a female patient aged 16, who consulted with

El pH de la carne de cobayo (Cavia porcellus procedente del manejo deficiente del bienestar animal durante el sacrificio en la sierra central del Perú.

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LUCAS JR

2017-09-01

Full Text Available En la región andina del Perú es común observar el sacrificio de los cobayos sin aturdimiento ni descanso ante mortem. El objetivo del presente estudio fue evaluar el pH de la carne de cobayo (Cavia porcellus resultante de este manejo. Se evaluó el pH de 60 canales a las 0, 1, 6, 12, y 24 h posteriores al sacrificio sin descanso ante mortem ni aturdimiento. El pH fue de 6.79 ± 0.3, 6.74 ± 0.34, 6.59 ± 0.28, 6.45 ± 0.35 y 5.96 ± 0.11, a la 0, 1, 6, 12 y 24 horas post sacrificio respectivamente. La ecuación que representa la evolución del pH fue Y=6.7765-0.0231X-0.0005X2 (R2=0.996. SUMMARY. The pH of guinea pig (Cavia porcellus meat from the welfare-deficient slaughtering in the Peruvian central Andes. In Andean region of Peru is common to slaughter Guinea pig without lairage and stunning. The aim of this study was to evaluate the pH of meat of Guinea pig (Cavia porcellus from the unsuitable welfare practices during slaughtering in the Peruvian central Andes. The pH of 60 guinea pig carcasses were analyzed at 0, 1, 6, 12 and 24 hours after the end of the slaughter process. The pH was 6.79 ± 0.3, 6.74 ± 0.34, 6.59 ± 0.28, 6.45 ± 0.35 and 5.96 ± 0.11 for 0, 1, 6, 12 y 24 h post slaughtering. The equation that graphs pH evolution was Y=6.7765-0.0231X-0.0005X2 (R2=0.996.

Los repositorios como herramienta para la recuperación del patrimonio bibliográfico: el caso de seis bibliotecas públicas municipales del departamento de Antioquia

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Wilson Castaño Muñoz

2016-01-01

Full Text Available El siguiente artículo tiene como objetivo principal evidenciar la importancia de implementar un repositorio digital en la investigaciones sobre la recuperación del patrimonio bibliográfico de seis bibliotecas públicas de los municipios de Andes, El Carmen de Viboral, Puerto Berrio, Sonsón, Turbo y Yarumal del departamento de Antioquia, Colombia. Se presenta brevemente el concepto de patrimonio-bibliográfico y se abordan los repositorios institucionales y digitales como categoría analítica y alternativa para la recuperación, organización y difusión de información patrimonial. The following article has as main objective to demonstrate the importance of implementing a digital repository in the research about the bibliographical patrimony recovery in six public libraries in municipalities located in the department of Antioquia, Colombia such as Andes, el Carmen de Viboral, Puerto Berrío, Sonsón, Turbo and Yarumal. The concept of bibliographical patrimony appears briefly in the article and the institutional and digital repositories are approached as an analytical and alternative category for the recovery, organization and dissemination of the patrimony information. .

Palm harvest impact in the western Amazon, Andes and Pacific lowlands

DEFF Research Database (Denmark)

Balslev, Henrik

2011-01-01

Palms are the most useful group of plants in tropical American forests and in this project we study the effect of extraction and trade of palms on forests in the western Amazon, Andes, and Pacific lowlands. We determine the size of the resource by making palm community studies in the different...

Evolution of the Chos Malal and Agrio fold and thrust belts, Andes of Neuquén: Insights from structural analysis and apatite fission track dating

Science.gov (United States)

Rojas Vera, E. A.; Mescua, J.; Folguera, A.; Becker, T. P.; Sagripanti, L.; Fennell, L.; Orts, D.; Ramos, V. A.

2015-12-01

The Chos Malal and Agrio fold and thrust belts are located in the western part of the Neuquén basin, an Andean retroarc basin of central-western Argentina. Both belts show evidence of tectonic inversion at the western part during Late Cretaceous times. The eastern part is dominated by late Miocene deformation which also partially reactivated the western structures. This work focuses on the study of the regional structure and the deformational event that shaped the relief of this part of the Andes. Based on new field work and structural data and previously published works a detailed map of the central part of the Neuquén basin is presented. Three regional structural cross sections were surveyed and balanced using the 2d Move™ software. In order to define a more accurate uplift history, new apatite fission track analyses were carried on selected structures. These data was used for new thermal history modeling of the inner part of the Agrio and Chos Malal fold and thrust belts. The results of the fission track analyses improve the knowledge of how these fold and thrust belts have grown trough time. Two main deformational events are defined in Late Cretaceous to Paleocene and Late Miocene times. Based on this regional structural analysis and the fission track data the precise location of the orogenic front for the Late Cretaceous-Paleocene times is reconstructed and it is proposed a structural evolution of this segment of the Andes. This new exhumation data show how the Late Cretaceous to Paleocene event was a continuous and uninterrupted deformational event.

Los santos patronos de los migrantes Mexicanos a Estados Unidos

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Rafael Alarcón

Full Text Available La mayor parte los migrantes mexicanos indocumentados que buscan encontrar un empleo en Estados Unidos son católicos, por esta razón, han incorporado a la devoción de los santos patronos sus tribulaciones que incluyen el trayecto desde sus comunidades de origen a la frontera norte, los peligros del cruce indocumentado, la búsqueda de trabajo y la posible deportación. El objetivo central de este artículo es analizar las características más importantes de tres devociones de los migrantes indocumentados en Tijuana, Baja California, México: Santo Toribio Romo, el "Santo Pollero" que fue canonizado en 2000, el Beato Juan Bautista Scalabrini, fundador de los Misioneros Scalabrinianos y Juan Soldado quien surgió de la religiosidad popular.

Political-Philosophical Perspectives about the Notions of Indian, Inca, and Mestizo on the «Comentarios reales de los Incas»

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Alejandro Javier Viveros Espinosa

2016-11-01

Full Text Available This essay posits certain political-philosophical perspectives on the Inca Garcilaso de la Vega’s Primera parte de los Comentarios reales de los Incas (1609. To this purpose we will develop two hermeneutical movements. The first refers to a theoretical and methodological questioning related to the notion of Indian as a discursive construction during colonial times in the Andes area. The second deploys a critical exercise grounded on the interaction between the notions of Indian, Inca, and Mestizo, which is focused on how they build alternative subjectivities. Both movements consolidate an interpretation about the Inca Garcilaso’s political-philosophical reflections, remarking his proposals of a bifurcated modern civilizational project in the New World.

Contrasting Climate Change Impact on River Flow from Glacierised Catchments in the Himalayan and Andes Mountains

Science.gov (United States)

Pellicciotti, F.; Ragettli, S.; Immerzeel, W. W. W.

2016-12-01

Glaciers and glacierised catchments in mountainous regions react to a changing climate in different manners depending on climate and glacier characteristics. Despite the key role of mountain ranges as natural water towers, their hydrological balance and future changes in glacier runoff associated with climate warming remain poorly understood because of high meteorological variability, physical inaccessibility and the complex interplay between climate, cryosphere and hydrological processes. We use a state-of-the art glacio-hydrological model informed by data from high altitude observations and the latest CMIP5 climate change scenarios to quantify the climate change impact on glaciers and runoff for two contrasting catchments vulnerable to changes in the cryosphere. The two catchments are located in the Central Andes of Chile and in the Nepalese Himalaya in close vicinity of densely populated areas. Although both sites are projected to experience a strong decrease in glacier area, they show remarkably different hydrological responses. Icemelt is on a rising limb in Langtang at least until 2041-2050 and starts to decrease afterwards, while in Juncal icemelt was already beyond its tipping point at the beginning of the 21st century. This contrasting response can be explained by differences in the elevation distribution of the glaciers in the two regions. In Juncal, many glaciers are melting up to the highest elevations already during the reference period (2000-2010) and increasing melt rates due to higher air temperatures cannot compensate the loss of glacier area. In Langtang, large sections of the glaciers at high elevations are currently not exposed to melt, but will be in the future, thus compensating for the loss of glacier area at lower elevations. As a result of these changes and projected changes in precipitation, in Juncal runoff will sharply decrease in the future and the runoff seasonality is sensitive to projected climatic changes. In Langtang, future water

Innovación en métodos computacionales en la Universidad los Andes

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Hernando Durán

2010-06-01

Full Text Available En 1967, se presentó en el Winter Power Meeting de laIEEE, en Nueva York, lo que constituyó tal vez elavance más importante en esa década respecto a métodoscomputacionales para calcular flujos de potenciaen redes eléctricas de centenares de nodos y pararesolver sistemas de ecuaciones lineales y no linealesde gran tamaño [1]. Hasta ese entonces, los flujos decarga más grandes que se podían resolver no pasabande sistemas de decenas de nodos.

Imaging the lithospheric structure of the Central Andes from the joint inversion of multiple seismic data sets

Science.gov (United States)

Ward, Kevin Michael

A lingering question in Cordilleran tectonics is how high plateaus form in the absence of continental collision. The type example of an active Cordilleran high plateau is found in the Central Andes of Peru, Bolivia, Argentina, and Chile. Along this section of the South American Cordillera, tectonics are primarily driven by subduction of the oceanic Nazca Plate beneath the continental South American Plate. Extending over 1,800 km along the active continental margin, the Central Andean Plateau (CAP) reaches a maximum width of around 400 km with several peaks in excess of 6 km. Numerous morphotectonic subdivisions of the CAP highlight the complex along-strike variability of the Plateau providing a natural laboratory for investigating the relative contribution of tectonic processes involved in building and maintaining Cordilleran high plateaus. The scale of this problem extends far beyond the scope of any one geoscientific discipline requiring a multidisciplinary approach. Our contribution to this scientific problem and the focus of the work presented in this dissertation is to better understand the current lithospheric and uppermost mantle structure along the CAP. This is achieved by integrating recent advances in seismic imaging techniques with a growing availability of high-quality seismic data into three distinct studies across the South American continent. In the first study, we present a shear-wave velocity model for the crust below the Altiplano-Puna Volcanic Complex (APVC). The target of this study is to constrain the crustal volume of a large magma reservoir inferred to exist below the APVC. When combined with geological and petrological constraints, the large-volume magma reservoir imaged in this study suggests a significant magmatic contribution to the growth of the Plateau in excess of one kilometer over the last ten million years. In addition to the tectonic contributions of this work, we introduce a new method of jointly inverting surface-wave dispersion

Plant community variation across a puna landscape in the Chilean Andes Variación en la comunidad vegetal de un paisaje de puna en los Andes chilenos

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JOHN G LAMBRINOS

2006-06-01

Full Text Available We describe patterns of plant species and growth form abundance in the puna vegetation of Parque Nacional Lauca, Chile. At more than 4,300 m, the extreme habitat of the study site supported relatively few species. These few species, however, represented a diverse array of growth forms that were organized with respect to distinct environmental gradients. Both species richness and growth form diversity increased with the degree of habitat rockiness and on more xeric north and east facing slopes. These xeric, rocky sites supported the greatest overall abundance of cushion forms. Less rocky sites with more soil development supported a greater abundance of tussock grass and shrub forms. Congeneric species occupied distinct microhabitats and were often markedly divergent in growth form. These patterns suggest that water and thermal stress are critical forces shaping functional form as well as community organization in the high Andean punaDescribimos los patrones de abundancia de las especies vegetales y las formas de vida en la vegetación de puna en el Parque Nacional Lauca, Chile. A una altitud que excede los 4.300 m de altitud, el hábitat extremo de nuestro sitio de estudio presenta relativamente pocas especies. Dichas especies, sin embargo, representan un arreglo diverso de formas de vida organizadas con respecto a distintos gradientes ambientales. Tanto la riqueza de especies como el hábito de crecimiento aumentaron en los suelos más rocosos y en las pendientes expuestas al norte y al este, cuya vegetación es más xerófila. Dichos sitios presentaron la mayor abundancia en formas de cojines. Los sitios menos rocosos con un suelo más desarrollado presentaron una mayor abundancia de pastos y arbustos. Distintos microhábitats fueron ocupados por especies congénericas que con frecuencia divergieron en su hábito de crecimiento. Los patrones observados sugieren que el agua y el estrés térmico son fuerzas críticas que moldean la forma

Interpreting compositional zonation of the Zaragoza ignimbrite from Los Humeros caldera, Central Mexico

Energy Technology Data Exchange (ETDEWEB)

Carrasco-Nunez, Gerardo [Centro de Geociencias, UNAM, Campus Juriquilla, Queretaro, Qro. (Mexico); McCurry, Michael [Department of Geology, Idaho State University, Pocatello, ID (United States); Branney, Michael J [Department of Geology, University of Leicester, Leicester (United Kingdom)

2008-10-01

Compositional zonation in ignimbrites is relatively common, and is often inferred to record gradual withdrawal by an eruption of a density-stratified magma chamber (with silicic magma towards the top and more dense, mafic magma at the bottom). We show that this model does not match observations at the ca. 0.1 Ma Zaragoza ignimbrite from Los Humeros caldera in central Mexico. Detailed petrologic studies reveal a more complex scenario: the ignimbrite exhibits a 'double' vertical zonation based on the compositions of pumice lapilli. We present evidence for mingling and limited mixing occurred during or immediately before the caldera-forming eruption. One possibility to explain the observations is that the ignimbrite eruption occurred in response to intrusion of a hybridized andesitic magma into a rhyodacitic magma chamber.

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Author Affiliations. G E DELGADO1 V SAGREDO2. Laboratorio de Cristalografía, Departamento de Química, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela; Laboratorio de Magnetismo en Sólidos, Departamento de Física, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, ...

On the generation of coastal lows in central Chile

International Nuclear Information System (INIS)

Rutllant, J.

1994-07-01

Previous studies of the coastal-low occurrences in central Chile have been aimed at the formulation of a conceptual model to explain observed features in connection with applied studies. The most prominent weather pattern associated with CL occurrences, (type A), coincides with the onset of a warm, middle-troposphere ridge over central Chile, and a surface high over northern Argentina. The synoptic forcing of the low is related to weak frontal disturbances that travel equatorwards. They result in a thickening of the marine layer that becomes blocked by the coastal escarpment, at the time of the onset of the ridge aloft. The blocking of the stable air above the subsidence inversion by the Andes is also hypothesized. The analysis of the subsidence inversion, the geometry of the coastal and Andes mountain ranges, and a scale analysis of the non-dimensional governing equations for the generation of the coastal lows, following the approach of Reason and Steyn (1990); leads to the conclusion that both blocking actions are strong and persistent in central Chile. An interactive mechanism between the upper and lower blocking effects is postulated to explain the cyclonic vorticity and the initial steering of the coastal lows. The scale analysis of the governing equations for the propagation stage of the low suggests that, departing for the South African case, non-linearity is important here, and that solitary Kelvin waves could be expected. Theoretical phase propagation speeds and Rossby radii are found to range between 8 and 15 m s-1 and 100-250 km, respectively. The importance of strong southerly winds ahead of the low and weak winds at its trailing edge is also stressed, as another major departure from the coastal-low behaviour elsewhere. (author). 17 refs, 4 figs, 4 tabs

El cura y sus hijos osos o el recorrido civilizador de los hijos de un cura y una osa

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1997-01-01

Full Text Available LE CURE ET SES ENFANTS OURS OU LE PARCOURS CIVILISATEUR DES ENFANTS D’UN CURE ET D’UNE OURSE. Cet article constitue un essai d’interprétation de deux versions quechuas cuzquéniennes du récit panandin connu comme “Jean de l’Ours” ou “Le fils de l’ours”. A partir d’une analyse du symbolisme du récit, la logique profonde qui l’ordonne est mise en lumière: la société humaine et civilisée ne peut se perpétuer sans établir des échanges et une coopération avec les êtres sauvages de l’au-delà. Les protagonistes, fils d’un curé et d’une ourse, ainsi que le curé lui-même, sont les héros médiateurs d’un récit mythique dont la logique prétend aussi s’appliquer aux relations interethniques dans les Andes. Este artículo presenta un ensayo de interpretación de dos versiones quechuas cuzqueñas del relato panandino conocido como “Juan Oso” o “El hijo del oso”. A partir de un análisis del simbolismo del relato, se saca a luz la lógica profunda que lo ordena: la sociedad humana y civilizada no puede perpetuarse sin establecer un intercambio y una cooperación con los seres salvajes del más allá. Los protagonistas, hijos de un cura y una osa, así como el cura mismo, son los héroes mediadores de un relato mítico cuya lógica pretende también aplicarse a las relaciones interétnicas en los Andes. THE PRIEST AND HIS BEAR CHILDREN OR THE PASSAGE TO CIVILIZATION OF THE CHILDREN OF A PRIEST AND A SHE-BEAR. This article sets out to interpret two Cuzco Quechua versions of the pan-Andean tale known as “Juan Oso” or “The Bear’s Son”. The analysis of the story’s symbolism sheds light on the profound logic on which it is based: human and civilized society cannot survive without establishing interchange and cooperation with wild beings from the other world. The protagonist, the son of the priest and the she-bear, as well as the priest himself, are the mediator heroes of a tale whose logic also applies to interethnic

Estimates of Carbon Reservoirs in High-Altitude Wetlands in the Colombian Andes

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Enrique Javier Peña

2009-10-01

Full Text Available The observed increase in emission of greenhouse gases, with attendant effects on global warming, have raised interests in identifying sources and sinks of carbon in the environment. Terrestrial carbon (C sequestration involves capture of atmospheric C through photosynthesis and storage in biota, soil and wetlands. Particularly, wetland systems function primarily as long-term reservoirs for atmospheric carbon dioxide (CO2 and as sources of atmospheric methane (CH4. The objective of this study was to evaluate the patterns of carbon reservoirs in two high-altitude wetlands in the central Andean mountain of Colombia. Carbon cycle in both systems is related mainly with the plant biomass dynamics from the littoral zone. Thus, total organic carbon concentrate an average up to 329 kg of N ha-1 and 125 kg of P ha-1 every year vs only 17 kg N ha-1 and 6 kg P ha-1 in the water column of the limnetic zone in the wetland, evidencing spatial differences in carbon concentrations for these types of ecosystems. Results revealed that these systems participate in the balance and sequestration of carbon in the Colombian Andes.

Valoración, partición y distribución de la tierra de los resguardos indígenas en una localidad andina venezolana. Santa Bárbara de Chachopo

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Samudio A., Edda O.

2010-12-01

Full Text Available The article examines the process of the establishment of Indian reserves (resguardos in the Venezuelan Andes in the late sixteenth century, and the experiences of their dissolution three centuries later. The main objective of the study is to analyze the appraisal, partition and distribution of the Indian reserves of Merida, assessing the role of the factors that were key elements in that process. The study includes aspects of the extinction of lands that were given with common and non-transferable title to the Indians settlements of Merida. The case of the pueblo of Santa Barbara de Chachopo is here offered as an example.

El artículo examina el proceso mediante el cual los Resguardos indígenas que fueron establecidos en la región andina venezolana en el tardío siglo XVI experimentaron su disolución tres centurias más tarde. El objetivo central de este trabajo es analizar la valoración, partición y distribución de esos Resguardos Indígenas de Mérida, tratando de apreciar la intervención de los factores que participan en ese hecho; para el estudio de los aspectos contemplados en el proceso de extinción de las tierras que fueron otorgadas, con carácter común e intransferible, a los pueblos de indios de Mérida; en esta ocasión, se tomó como ejemplo el caso de Santa Bárbara de Chachopo.

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Laboratorio de Cristalografía, Departamento de Química, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela; Centro de Estudios de Semiconductores, Departamento de Física, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela; Laboratorio de Análisis Químico y Estructural, ...

Cyber Foraging for Improving Survivability of Mobile Systems

Science.gov (United States)

2016-02-10

Cyber-Foraging for Improving Survivability of Mobile Systems Sebastián Echeverría ( Universidad de los Andes) Grace A. Lewis James Root Ben...NUMBERS FA8721-05-C-0003 6. AUTHOR(S) Sebastián Echeverría ( Universidad de los Andes), Grace A. Lewis, James Root, & Ben Bradshaw 7. PERFORMING

Hybrid Literacies: The Case of a Quechua Community in the Andes

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de la Piedra, Maria Teresa

2009-01-01

Drawing on data from an ethnographic study in a Quechua rural community in the Peruvian Andes, this article examines hybrid literacy practices among bilingual rural speakers in the context of the household and the community. I examine the coexistence of two types of textual practices that operate side by side, at times integrated in the same…

ISOSTATICALLY DISTURBED TERRAIN OF NORTHWESTERN ANDES MOUNTAINS FROM SPECTRALLY CORRELATED FREE-AIR AND GRAVITY TERRAIN DATA

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Hernández P Orlando

2006-12-01

Full Text Available Recently revised models on global tectonics describe the convergence of the North Andes, Nazca, Caribbean and South American Plates and their seismicity, volcanism, active faulting and extreme
topography. The current plate boundaries of the area are mainly interpreted from volcanic and seismic datasets with variable confidence levels. New insights on the isostatic state and plate boundaries of
the northwestern Andes Mountains can be obtained from the spectral analysis of recently available gravity and topography data.
Isostatically disturbed terrain produces free-air anomalies that are highly correlated with the gravity effects of the terrain. The terrain gravity effects (TGE and free air gravity anomalies (FAGA of the
Andes mountains spectral correlation data confirms that these mountains are isostatically disturbed. Strong negative terrain-correlated FAGA along western South America and the Greater and Lesser Antilles are consistent with anomalously deepened mantle displaced by subducting oceanic plates.

Inversion of the compensated terrain gravity effects (CTGE reveals plate subduction systems with alternating shallower and steeper subduction angles. The gravity modeling highlights crustal
deformation from plate collision and subduction and other constraints on the tectonism of the plate boundary zones for the region.

Automated recognition of quasi-planar ignimbrite sheets and paleo-surfaces via robust segmentation of DTM - examples from the Western Cordillera of the Central Andes

Science.gov (United States)

Székely, B.; Karátson, D.; Koma, Zs.; Dorninger, P.; Wörner, G.; Brandmeier, M.; Nothegger, C.

2012-04-01

The Western slope of the Central Andes between 22° and 17°S is characterized by large, quasi-planar landforms with tilted ignimbrite surfaces and overlying younger sedimentary deposits (e.g. Nazca, Oxaya, Huaylillas ignimbrites). These surfaces were only modified by tectonic uplift and tilting of the Western Cordillera preserving minor now fossilized drainage systems. Several deep, canyons started to form from about 5 Ma ago. Due to tectonic oversteepening in a arid region of very low erosion rates, gravitational collapses and landslides additionally modified the Andean slope and valley flanks. Large areas of fossil surfaces, however, remain. The age of these surfaces has been dated between 11 Ma and 25 Ma at elevations of 3500 m in the Precordillera and at c. 1000 m near the coast. Due to their excellent preservation, our aim is to identify, delineate, and reconstruct these original ignimbrite and sediment surfaces via a sophisticated evaluation of SRTM DEMs. The technique we use here is a robust morphological segmentation method that is insensitive to a certain amount of outliers, even if they are spatially correlated. This paves the way to identify common local planar features and combine these into larger areas of a particular surface segment. Erosional dissection and faulting, tilting and folding define subdomains, and thus the original quasi-planar surfaces are modified. Additional processes may create younger surfaces, such as sedimentary floodplains and salt pans. The procedure is tuned to provide a distinction of these features. The technique is based on the evaluation of local normal vectors (perpendicular to the actual surface) that are obtained by determination of locally fitting planes. Then, this initial set of normal vectors are gradually classified into groups with similar properties providing candidate point clouds that are quasi co-planar. The quasi co-planar sets of points are analysed further against other criteria, such as number of minimum

A phytosociological analysis and synopsis of the dry woodlands and succulent vegetation of the Peruvian Andes

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ANTONIO GALÁN-DE-MERA

2016-01-01

Full Text Available ABSTRACT A phytosociological approach to dry forest and cactus communities on the occidental slopes of the Peruvian Andes is presented in base of 164 plots carried out following the Braun-Blanquet method. From them, 52 have been made recently, and the other 112 were taken from the literature. After a multivariate analysis, using a hierarchical clustering and a detendred correspondence analysis, the Acacio-Prosopidetea class (dry forest and cactus communities, developed on soils with some edaphic humidity or precipitations derived from El Niño Current, the Opuntietea sphaericae class (cactus communities of central and southern Peru, on few stabilized rocky or sandy soils and the Carico-Caesalpinietea class (dry forests of the Peruvian coastal desert, influenced by the maritime humidity of the cold Humboldt Current, are differentiated. Within the Acacio-Prosopidetea class, two alliances are commented: the Bursero-Prosopidion pallidae (with two new associations Loxopterygio huasanginis-Neoraimondietum arequipensis and Crotono ruiziani-Acacietum macracanthae, and the new alliance Baccharido-Jacarandion acutifoliae (with the new associations Armatocereo balsasensis-Cercidietum praecocis and Diplopterydo leiocarpae-Acacietum macracanthae. For the Opuntietea sphaericae class, the association Haageocereo versicoloris-Armatocereetum proceri (Espostoo-Neoraimondion is described on the basis of plots from hyperarid localities of central Peru. Finally, a typological classification of the studied plant communities is given.

A phytosociological analysis and synopsis of the dry woodlands and succulent vegetation of the Peruvian Andes.

Science.gov (United States)

Galán-DE-Mera, Antonio; Sánchez-Vega, Isidoro; Linares-Perea, Eliana; Campos, José; Montoya, Juan; Vicente-Orellana, José A

2016-01-01

A phytosociological approach to dry forest and cactus communities on the occidental slopes of the Peruvian Andes is presented in base of 164 plots carried out following the Braun-Blanquet method. From them, 52 have been made recently, and the other 112 were taken from the literature. After a multivariate analysis, using a hierarchical clustering and a detendred correspondence analysis, the Acacio-Prosopidetea class (dry forest and cactus communities, developed on soils with some edaphic humidity or precipitations derived from El Niño Current), the Opuntietea sphaericae class (cactus communities of central and southern Peru, on few stabilized rocky or sandy soils) and the Carico-Caesalpinietea class (dry forests of the Peruvian coastal desert, influenced by the maritime humidity of the cold Humboldt Current), are differentiated. Within the Acacio-Prosopidetea class, two alliances are commented: the Bursero-Prosopidion pallidae (with two new associations Loxopterygio huasanginis-Neoraimondietum arequipensis and Crotono ruiziani-Acacietum macracanthae), and the new alliance Baccharido-Jacarandion acutifoliae (with the new associations Armatocereo balsasensis-Cercidietum praecocis and Diplopterydo leiocarpae-Acacietum macracanthae). For the Opuntietea sphaericae class, the association Haageocereo versicoloris-Armatocereetum proceri (Espostoo-Neoraimondion) is described on the basis of plots from hyperarid localities of central Peru. Finally, a typological classification of the studied plant communities is given.

The analytic nodal diffusion solver ANDES in multigroups for 3D rectangular geometry: Development and performance analysis

International Nuclear Information System (INIS)

Lozano, Juan-Andres; Garcia-Herranz, Nuria; Ahnert, Carol; Aragones, Jose-Maria

2008-01-01

In this work we address the development and implementation of the analytic coarse-mesh finite-difference (ACMFD) method in a nodal neutron diffusion solver called ANDES. The first version of the solver is implemented in any number of neutron energy groups, and in 3D Cartesian geometries; thus it mainly addresses PWR and BWR core simulations. The details about the generalization to multigroups and 3D, as well as the implementation of the method are given. The transverse integration procedure is the scheme chosen to extend the ACMFD formulation to multidimensional problems. The role of the transverse leakage treatment in the accuracy of the nodal solutions is analyzed in detail: the involved assumptions, the limitations of the method in terms of nodal width, the alternative approaches to implement the transverse leakage terms in nodal methods - implicit or explicit -, and the error assessment due to transverse integration. A new approach for solving the control rod 'cusping' problem, based on the direct application of the ACMFD method, is also developed and implemented in ANDES. The solver architecture turns ANDES into an user-friendly, modular and easily linkable tool, as required to be integrated into common software platforms for multi-scale and multi-physics simulations. ANDES can be used either as a stand-alone nodal code or as a solver to accelerate the convergence of whole core pin-by-pin code systems. The verification and performance of the solver are demonstrated using both proof-of-principle test cases and well-referenced international benchmarks

High-resolution paleoclimate records of Holocene hydroclimatic variability in the Eastern Colombian Andes from Lago de Tota

Science.gov (United States)

Ahmed, M. N.; Bird, B. W.; Escobar, J.; Polissar, P. J.

2017-12-01

The Northern Hemisphere (NH) South American Monsoon (SAM) is a significant source of precipitation for the North Andes (north of 0˚) and has major control over regional hydroclimate variability. Holocene-length histories of NH SAM variability are few compared to the Southern Hemisphere (SH), limiting understanding of how these systems are connected on orbital and shorter timescales. Here, we present multi-proxy lake-sediment-based paleoclimate and paleohydrologic reconstructions from Lago de Tota, Colombia, using sedimentological, geochemical and leaf-wax hydrogen isotopic indicators from radiometically dated cores. The results indicate periods of wet and dry climate phases during the past 9000 BP with an average Holocene sedimentation rate 33cm/kyr. An increase in total organic matter (TOM) content and finer grain-size distributions was observed from 8000 to 3200 BP, suggesting a period of high lake level. This was followed by lower TOM and coarser grain sizes, suggesting lower lake levels from 3200 BP to the present. Although Tota's lake level pattern is antiphased with other lake level reconstructions from the NH and SH Andes, it is consistent with hypothesized changes in atmospheric convection over the Andes during the Holocene and the way in which they would be modified by the so-called dry island effect in the Colombian Andes. This suggests that a common forcing mechanism can be invoked to explain differing millennial-scale Andean hydroclimate changes, namely atmospheric convection. Orbital and Pacific atmosphere-forcing are therefore likely to have played a significant role in driving pan-Andean hydroclimate variability based on their inter-hemispheric influence on Andean convection.

Consecuencias de las variaciones microclimáticas sobre la visita de insectos polinizadores en dos especies de Chaetanthera (Asteraceae en los Andes de Chile central Consequences of microclimate variation on insect pollinator visitation in two species of Chaetanthera (Asteraceae in the central Chilean Andes

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CRISTIAN TORRES-DÍAZ

2007-12-01

Full Text Available La actividad de polinizadores puede ser afectada por factores bióticos (e.g., densidad floral en el parche, despliegue floral o por factores abióticos (e.g., temperatura, velocidad de viento, nubosidad. A pesar de la notable variación local, estacional e interanual en temperatura en zonas alpinas, las consecuencias de la variación microclimática local sobre la actividad de los polinizadores han recibido escasa atención en ambientes de alta montaña. En este estudio comparamos las tasas de visita a flores de polinizadores realizadas sobre poblaciones de exposición norte y oeste, en Chaetanthera apiculata (3.100 m de altitud, y en poblaciones de exposición este y oeste en C. lycopodioides (3.300 m de altitud. Se estudiaron los sistemas de reproducción de ambas especies para determinar su nivel de dependencia de un agente de polinización externo. En C. apiculata, la población que crece sobre la ladera de exposición norte estuvo sujeta a mayores temperaturas diurnas (1,8 °C y mayores tasas de visita (7,8 veces que la población sobre la ladera de exposición oeste. En C. lycopodioides, a su vez, la ladera de exposición este fue más cálida (3 °C y más visitada (cuatro veces que la población de exposición oeste. Mientras en C. apiculata, solo Faunula leucoglene (Lepidóptera: Satyridae presentó mayor actividad en la población más cálida, en C. lycopodioides, solo F. leucoglene y Liphantus sp. (Himenóptera: Andrenidae tuvieron mayor actividad en la población más cálida. La tasa de visitas de Faunula leucoglene fue afectada por la temperatura en C. apiculata y C. lycopodioides. Ambas especies, C. apiculata y C. lycopodioides, son parcialmente autocompatibles, y por lo tanto requieren polen exógeno para alcanzar una producción de semillas máxima. Nuestros resultados muestran que en ambientes de alta montaña las tasas de visita de polinizadores son altamente variables y que los factores microclimáticos pueden generar m

La negociación centro-región en Chile: realidad o mito - el caso de la región de Los Lagos Central-regional negotiation in Chile: reality or myth - the case of the Los Lagos region

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Pablo Aurelio Monje Reyes

2007-08-01

Full Text Available A partir de la década de los 1990, la descentralización política-administrativa de Chile se ha profundizado en forma gradual. Ello se ha expresado, entre otros aspectos, en la creación de gobiernos regionales y en la disposición política del gobierno central de dejar en manos de estas instancias el manejo de recursos para la inversión regional. No obstante, la reconfiguración de la actual división de las regiones no se ha tomado como un tema prioritario dentro de la política descentralizadora en cuestión. Sin embargo, ello no ha implicado que se esté obviando el tema por completo; ya que a nivel extraoficial, y de parte tanto del gobierno central como regional, se plantea la necesidad de hacer una propuesta de reestructuración de la división política-administrativa del país. Este estudio de caso fija su atención en las demandas de reestructuración recién mencionadas, haciendo especial hincapié en la observación del fenómeno de demanda por la regionalización de la provincia de Valdivia, en la décima región de Los Lagos, Chile, durante los años 1995/96. Dicho trabajo se realizó bajo la óptica de la negociación centro-región, con los objetivos de describir los componentes del proceso y de reconocer las condicionantes de las acciones de los actores en el mismo. Los resultados del estudio están vinculados al rol que ejercen los actores en el conflicto y negociación centro-región. Se consiguió realizar una caracterización de ellos, además de constatar la relación de clientela política que se produce entre la elite nacional y regional, como factor determinante en el resultado de la negociación. De la misma manera, se comprobó que el diseño institucional del sistema político induce este tipo de vínculo entre las elites mencionadas. Finalmente, el estudio presenta una serie de recomendaciones para el fortalecimiento de la política pública de descentralización de Chile, que están en marco de aminorar los

Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago

Science.gov (United States)

Eichler, A.; Gramlich, G.; Kellerhals, T.; Tobler, L.; Rehren, Th.; Schwikowski, M.

2017-01-01

The importance of metallurgy for social and economic development is indisputable. Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Comprehensive archaeological findings point to first sophisticated Cu metallurgy during the Moche culture ~200-800 AD, whereas peat-bog records from southern South America suggest earliest pollution potentially from Cu smelting as far back as ~2000 BC. Here we present a 6500-years Cu emission history for the Andean Altiplano, based on ice-core records from Illimani glacier in Bolivia, providing the first complete history of large-scale Cu smelting activities in South America. We find earliest anthropogenic Cu pollution during the Early Horizon period ~700-50 BC, and attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures.

Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago.

Science.gov (United States)

Eichler, A; Gramlich, G; Kellerhals, T; Tobler, L; Rehren, Th; Schwikowski, M

2017-01-31

The importance of metallurgy for social and economic development is indisputable. Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Comprehensive archaeological findings point to first sophisticated Cu metallurgy during the Moche culture ~200-800 AD, whereas peat-bog records from southern South America suggest earliest pollution potentially from Cu smelting as far back as ~2000 BC. Here we present a 6500-years Cu emission history for the Andean Altiplano, based on ice-core records from Illimani glacier in Bolivia, providing the first complete history of large-scale Cu smelting activities in South America. We find earliest anthropogenic Cu pollution during the Early Horizon period ~700-50 BC, and attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures.

Three new species of Pristimantis (Lissamphibia, Anura from montane forests of the Cordillera Yanachaga in Central Peru

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William E. Duellman

2007-12-01

Full Text Available We describe three additional new species of Pristimantis from the Cordillera Yanachaga, a part of the Andes in central Peru. Analyses of DNA sequences of the mitochondrial rRNA genes show that onespecies is a close relative of P. bipunctatus (P. conspicillatus Group, another is a close relative of P. stictogaster (P. peruvianus Group, and the third is related to several species in the P. unistrigatus Group. The first two species are morphologically similar to their closest relatives but occur at lower elevations. Twenty-nine species of Pristimantis and Phrynopus are known from the vicinity of the Cordillera Yanachaga. The number of species, especially of Pristimantis, is high in the humid montane forestin comparison with other sites in humid montane forests in Peru, but the number is lower than on the western slopes of the Andes in Ecuador.

Species richness and origin of the bryophyte flora of the Colombian Andes

NARCIS (Netherlands)

Gradstein, S.R.; Reenen, van G.B.A.; Griffin, D.

1988-01-01

Based on data from the ECOANDES project, a phytogeographical analysis has been made of the bryophyte flora along the wet, foggy western slope (1000-4500 m) and the drier eastern slope (500-4500 m) of the Colombian Central Cordillera at the ‘Parque de los Nevados’. Species richness increases with

La fuerza de los caminos sonoros: caminata y música en Qoyllurit’i

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Zoila Mendoza

2010-12-01

Full Text Available En este trabajo exploro la relación intrínseca que existe para los pobladores del distrito de Pomacanchi, Cusco, entre el caminar al santuario del Señor de Qoyllurit’i y la música que los acompaña. Mi atención se centra en la relación con la melodía chakiri wayri y, en menor medida, con la del alawaru. En esta relación intrínseca entre música y camino se revela, por un lado, la primacía que para los pobladores andinos tiene la unidad de lo visual y lo auditivo en los procesos cognitivos. Por otro, al explorar esta relación en el contexto de la caminata, una tercera dimensión sensorial clave en dichos procesos cognitivos también aparece claramente. Se trata del sentido de la cinestesia o sensación del movimiento. En otras palabras, la unidad de lo visual, lo sonoro y el movimiento es lo que hace de la participación en la fiesta en honor al Señor de Qoyllurit’i una experiencia única e imborrable. La obvia primacía de la unidad de los tres sentidos en la experiencia de peregrinación de los pomacanchinos al Señor de Qoyllurit’i no es única o exclusiva de este contexto festivo o de este pueblo. Simplemente esta experiencia nos permite analizar más de cerca un fenómeno que creo extendido en los Andes.

Photosynthetic responses to temperature and light of Antarctic and Andean populations of Colobanthus quitensis (Caryophyllaceae Respuestas fotosintéticas a la temperatura y a la luz de poblaciones antarticas y andinas de Colobanthus quitensis (Caryophyllaceae

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ÁNGELA SIERRA-ALMEIDA

2007-09-01

Full Text Available Colobanthus quitensis (Kunth, 1831 Bartling (Caryophyllaceae is characterized by a wide latitudinal distribution, ranging between the tropical high Andes and the Antarctic Peninsula. Although both habitat types are characterized by cold and freezing temperatures, important microclimatic differences exist during the growing season. Hence, important differences in the response of the photosynthetic apparatus to abiotic factors could be expected between Antarctic and Andean populations of C. quitensis. We studied the relationship between net photosynthesis, leaf temperature and light intensity in two populations of C. quitensis, one from La Parva in the Andes of central Chile and the other from King George Island, in the Maritime Antarctic. Plants from both populations were grown in the laboratory at 15 °C under 250 μmol photons m-2 s-1, with a 16/8 h light/dark photoperiod. Twenty plants (about two months old of each population were transferred to a 4 °C chamber with the same light and photoperiod conditions as above to assess the photosynthetic acclimation capacity. At 15 °C, populations differed in their optimum leaf temperature for photosynthesis, being 24.0 °C in individuals from the Andes and 18.6 °C in individuals from the Antarctic. In contrast, Antarctic individuals showed the highest net photosynthesis rate under both temperature treatments, with the lowest light compensation and saturation points. Antarctic individuals had higher photosynthetic activity at lower temperatures compared to individuals from the Andes. Our results suggest that C. quitensis has adapted photosynthetic performance of individuals growing in different localities to the prevailing climatic conditions. Differences in photosynthetic responses to temperature and light are discussed in relation to ecotypic differentiation between two populations studiedColobanthus quitensis es una especie ampliamente distribuida, que crece desde los Andes tropicales hasta la Pen

Volcanic impediments in the progressive development of pre-Columbian civilizations in the Ecuadorian Andes

Science.gov (United States)

Hall, Minard L.; Mothes, Patricia A.

2008-10-01

Archaeological investigations in Ecuador have proposed that there appear to be hiatus or anomalous jumps in the progressive development of pre-Columbian indigenous cultures, based upon the fact that their ceramics and tools demonstrate abrupt advances in their sophistication at several horizons in the soil profile. Because some of these horizons are clearly associated with volcanic ash layers, archaeologists have sought a causal relation with volcanism, that is, the eruptive events or their products severely interfered with the early inhabitants, resulting in their abandonment of certain areas. Geological studies of the young volcanoes in the Ecuadorian Andes carried out during the past two decades now allow us to make a more thorough evaluation of the role of volcanism during the Holocene. This contribution briefly describes the principal Holocene volcanic events and the distribution of the corresponding eruptive products found along the InterAndean Valley, from southern Colombia to central Ecuador. Only those events that were sufficiently large that they could have had a detrimental effect on the valley's early residents are discussed. Dacitic and rhyolitic ash flows, as well as numerous debris flows (lahars) have occurred frequently and their deposits cover many valleys and floodplains, where early inhabitants probably settled. The enormous Chillos Valley lahar, associated with the 4500 yBP eruption of Cotopaxi volcano, buried soils containing ceramics of the early Formative Period. However, the greatest impact upon mankind was probably not these short-lived violent events, but rather the burying of settlements and agricultural fields by ash fallout, the effect of which may have lasted hundreds of years. Ash fall layers are observed in pre-Columbian cultural horizons in the soil profile, occurring in the InterAndean Valley, the lower flanks of the Andes, and along Ecuador's Pacific coast, the oldest corresponding to the 5800 yBP eruption of Cotopaxi. This brief

Evaluación de las causas de los eventos adversos o incidentes que afectan la seguridad del paciente, en el hospital central de la policía de enero 2012 a diciembre 2013

OpenAIRE

Alarcon Ruiz, Diego Jesus; Gil Vargas, Luis Fabio

2016-01-01

TITULO DEL TRABAJO: Evaluación de las causas de los eventos adversos o incidentes que afectan la seguridad del paciente, en el hospital central de la policía de enero 2012 a diciembre 2013. OBJETIVO: Determinar y analizar la causa raíz de los principales factores de riesgo que afectan la seguridad del paciente que puedan ocasionar eventos adversos en la atención de los pacientes, con el uso de la teoría de restricciones TOC en el Hospital Central de la Policía HOCEN. MATERIALES Y METODO: Se r...

Temporal Analysis of Andes Virus and Sin Nombre Virus Infections of Syrian Hamsters

Science.gov (United States)

2007-05-01

Microbiology . All Rights Reserved. Temporal Analysis of Andes Virus and Sin Nombre Virus Infections of Syrian Hamsters Victoria Wahl-Jensen,1 Jennifer...Ye, C., J. Prescott , R. Nofchissey, D. Goade, and B. Hjelle. 2004. Neutralizing antibodies and Sin Nombre virus RNA after recovery from hantavirus

Análisis del estado estructural y administrativo de los campos de juego de los distritos urbanos de Ulloa, San Francisco, Heredia Centro y Mercedes del Cantón Central de la provincia de Heredia

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María Morera Castro

2010-01-01

Full Text Available El propósito de esta investigación fue analizar los factores que influirían en el estado estructural y administrativo de los campos de juegos en cuatro distritos urbanos del Cantón Central de la provincia de Heredia. En esta investigación mixta se analizó una muestra del 40% de los cien campos de juego en estudio, por medio de una hoja de evaluación del estado estructural de los aparatos, una entrevista estructurada y la técnica de recopilación pictórica. El estado general de los campos de juego se ve afectado por aspectos como desechos, la falta de basureros, la iluminación, entre otros. Asimismo, la diversidad de aparatos en los campos de juegos es escasa y el daño más frecuente es la herrumbre. El mantenimiento lo brindaba en la mayoría de los casos la propia comunidad o la Municipalidad de Heredia y los planes de mantenimiento eran escasos o nulos. Los campos de juego son actualmente espacios poco seguros que cuentan con peligros como la corrosión de las estructuras, puntas filosas y aparatos dañados. Por lo tanto, requieren una atención inmediata de las autoridades pertinentes y, en su mayoría, no están cumpliendo con el objetivo de su creación.

Canyon incision chronology based on ignimbrite stratigraphy and cut-and-fill sediment sequences in SW Peru documents intermittent uplift of the western Central Andes

Science.gov (United States)

Thouret, Jean-Claude; Gunnell, Yanni; Jicha, Brian R.; Paquette, Jean-Louis; Braucher, Régis

2017-12-01

Based on an 40Ar/39Ar- and U/Pb-based chronostratigraphy of ignimbrite sheets and the geomorphological features of watersheds, river profiles and slope deposits in the Ocoña-Cotahuasi-Marán (OCM) and Colca valleys of southwest Peru, we reconstruct the valley incision history of the western Central Andes over the last c. 25 Myr. We further document the Pleistocene and Holocene evolution of deep valleys on the basis of 14 10Be surface-exposure ages obtained on debris-avalanche deposits and river straths. The data suggest that uplift was gradual over the past 25 Myr, but accelerated after c. 9 Ma. Valley incision started around 11-9 Ma and accelerated between 5 and 4 Ma. Incision was followed by several pulses of valley cut-and-fill after 2.3 Ma. Evidence presented suggest that the post-5 Ma sequence of accelerated canyon incision probably resulted from a combination of drainage piracy from the Cordilleran drainage divide towards the Altiplano, accentuated flexural tilting of the Western Cordillera towards the SE, and increased rainfall on the Altiplano after late Miocene uplift of the Eastern Cordillera. The valley deepening and slope steepening driven by tectonic uplift gave rise to large occurrences of rockslope failure. The collapsed rock masses periodically obstructed the canyons, thus causing abrupt changes in local base levels and interfering with the steadiness of fluvial incision. As a result, channel aggradation has prevailed in the lower-gradient, U-shaped Pacific-rim canyons, whereas re-incision through landslide deposits has occurred more rapidly across the steeper V-shaped, upper valleys. Existing canyon knickpoints are currently arrested at the boundary between the plutonic bedrock and widespread outcrops of middle Miocene ignimbritic caprock, where groundwater sapping favouring rock collapse may be the dominant process driving headward erosion.

Papiloma de los plexos coroideos

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Ivón Aimé Sánchez Monterrey

2012-03-01

Full Text Available Los papilomas de los plexos coroideos son tumores infrecuentes de origen neuroectodérmico, que representan menos del 5 % del total de los tumores del sistema nervioso central en pediatría. La clínica suele estar provocada por el aumento de presión intracraneal debido a la hidrocefalia, con la que habitualmente cursan. La cirugía es curativa, con un porcentaje de supervivencia de casi el 100 % a los 5 años y ocasionales recurrencias. Se presenta el caso de un recién nacido con diagnóstico de papiloma de los plexos coroideos y evolución favorable.

Limnología de un Lago Tropical de Alta Montaña, en Ecuador: características de los sedimentos y tasa de sedimentación

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Günter Gunkel

2003-06-01

Full Text Available Se han realizado estudios sedimentológicos en el Lago San Pablo, un lago tropical de alta montaña, situado en los Andes del Ecuador, a 2 660 m sobre el nivel del mar. El lago presenta características propias de un estado eutrófico y, como consecuencia de esto se ha observado un crecimiento intenso de macrófitas y un hypolimnion anóxico con contenido de sulfitos orgánicos en los sedimentos. A partir de las características físico-químicas de los sedimentos superficiales, se ha podido establecer una distribución homogénea de éstos a lo largo y ancho del fondo de la cubeta. Los perfiles verticales mostraron altos contenidos de fósforo (4.3 g/kg en peso seco y una baja relación Fe/P (4.0, indicando una deficiente capacidad de retención de fósforo. La tasa de sedimentación pudo ser determinada mediante la aplicación de la prueba de 210 Pb, con la cual se obtuvo un valor de 3.5 mm/año. El análisis del contenido de 137 Cs no fue significativo debido a los bajos valores obtenidos. Los análisis verticales de sedimentos destacan el incremento de los depósitos de fósforo durante los últimos 110 años, pero este incremento representa el 50% de la concentración previa, lo cual es bastante moderado. En el pasado los ingresos de fósforo al lago también fueron altos, y se debieron a procesos naturales. Los lagos tropicales de alta montaña estudiados en el Ecuador, muestran una tendencia hacia la eutroficación. Este hecho es contradictorio, ya que estos lagos se encuentran en zonas poco pobladas y de bajo desarrollo de la vegetación.Equatorial high mountain lakes are a special type of lake occurring mainly in the South American Andes as well as in Central Africa and Asia. They occur at altitudes of a few thousand meters above sea level and are cold-water lakes (< 20°C. Relatively little is known about them. A long-term limnological study was therefore undertaken at Lake San Pablo, Ecuador, to analyze the basic limnological

Air temperature change in the northern and southern tropical Andes linked to North-Atlantic stadials and Greenland interstadials

Science.gov (United States)

Urrego, Dunia H.; Hooghiemstra, Henry

2016-04-01

We use eight pollen records reflecting climatic and environmental change from northern and southern sites in the tropical Andes. Our analysis focuses on the signature of millennial-scale climate variability during the last 30,000 years, in particular the Younger Dryas (YD), Heinrich stadials (HS) and Greenland interstadials (GI). We identify rapid responses of the vegetation to millennial-scale climate variability in the tropical Andes. The signature of HS and the YD are generally recorded as downslope migrations of the upper forest line (UFL), and are likely linked to air temperature cooling. The GI1 signal is overall comparable between northern and southern records and indicates upslope UFL migrations and warming in the tropical Andes. Our marker for lake level changes indicates a north to south difference that could be related to moisture availability. The direction of air temperature change recorded by the Andean vegetation is consistent with millennial-scale cryosphere and sea surface temperature records from the American tropics, but suggests a potential difference between the magnitude of temperature change in the ocean and the atmosphere.

Aridity changes in the temperate-Mediterranean transition of the Andes since ad 1346 reconstructed from tree-rings

Energy Technology Data Exchange (ETDEWEB)

Christie, Duncan A.; Quesne, Carlos le [Universidad Austral de Chile, Laboratorio de Dendrocronologia, Facultad de Ciencias Forestales y Recursos Naturales, Valdivia (Chile); Boninsegna, Jose A.; Morales, Mariano S.; Villalba, Ricardo [Instituto Argentino de Nivologia, Glaciologia y Ciencias Ambientales, IANIGLA, Departamento de Dendrocronologia e Historia Ambiental, Mendoza (Argentina); Cleaveland, Malcolm K.; Stahle, David W. [University of Arkansas Fayetteville, Tree-Ring Laboratory, Department of Geosciences, Fayetteville, AR (United States); Lara, Antonio [Universidad Austral de Chile, Laboratorio de Dendrocronologia, Facultad de Ciencias Forestales y Recursos Naturales, Valdivia (Chile); Universidad Austral de Chile, Forest Ecosystem Services under Climatic Fluctuations (Forecos), Valdivia (Chile); Mudelsee, Manfred [Climate Risk Analysis, Hanover (Germany); Alfred Wegener Institute for Polar and Marine Research, Bremerhaven (Germany)

2011-04-15

The Andes Cordillera acts as regional ''Water Towers'' for several countries and encompasses a wide range of ecosystems and climates. Several hydroclimatic changes have been described for portions of the Andes during recent years, including glacier retreat, negative precipitation trends, an elevation rise in the 0 isotherm, and changes in regional streamflow regimes. The Temperate-Mediterranean transition (TMT) zone of the Andes (35.5 -39.5 S) is particularly at risk to climate change because it is a biodiversity hotspot with heavy human population pressure on water resources. In this paper we utilize a new tree-ring network of Austrocedrus chilensis to reconstruct past variations in regional moisture in the TMT of the Andes by means of the Palmer Drought Severity Index (PDSI). The reconstruction covers the past 657 years and captures interannual to decadal scales of variability in late spring-early summer PDSI. These changes are related to the north-south oscillations in moisture conditions between the Mediterranean and Temperate climates of the Andes as a consequence of the latitudinal position of the storm tracks forced by large-scale circulation modes. Kernel estimation of occurrence rates reveals an unprecedented increment of severe and extreme drought events during the last century in the context of the previous six centuries. Moisture conditions in our study region are linked to tropical and high-latitude ocean-atmospheric forcing, with PDSI positively related to Nino-3.4 SST during spring and strongly negatively correlated with the Antarctic Oscillation (AAO) during summer. Geopotential anomaly maps at 500-hPa show that extreme dry years are tightly associated with negative height anomalies in the Ross-Amundsen Seas, in concordance with the strong negative relationship between PDSI and AAO. The twentieth century increase in extreme drought events in the TMT may not be related to ENSO but to the positive AAO trend during late-spring and

High altitude C4 grasslands in the northern Andes: relicts from glacial conditions?

NARCIS (Netherlands)

Boom, A.; Mora, G.; Cleef, A.M.; Hooghiemstra, H.

2001-01-01

The altitudinal vegetation distribution in the northern Andes during glacial time differed from the present-day conditions as a result of temperature and precipitation change. New evidence indicate that as a response to a reduced atmospheric partial CO2 pressure (pCO2), the competitive balance

Mammalian carnivore occupancy is inversely related to presence of domestic dogs in the high Andes of Ecuador.

Science.gov (United States)

Zapata-Ríos, Galo; Branch, Lyn C

2018-01-01

Although the Andes have long been occupied by people, habitat loss, fragmentation through deforestation, and other human activities such as introduction of invasive species have increased drastically during the past century. The Ecuadorian Andes are considered a biodiversity hotspot. However, the fauna and threats to the region are poorly studied, and understanding of factors that shape the distribution of species in habitats disturbed by human activities is needed to identify and mitigate region-wide threats to wildlife. We evaluated factors associated with patterns of occurrence of Andean carnivores in landscapes of the northern Ecuadorian Andes, particularly habitat loss, fragmentation, and occupancy of domestic dogs, and determined whether thresholds occurred for these factors beyond which carnivore occurrence declined markedly. Five study areas (each 20 x 20 km) were surveyed with a total effort of 2,800 camera trap nights. Occupancies of four of the eight carnivores known from the region were best predicted by occupancy of domestic dogs rather than measures of habitat loss and fragmentation [Andean fox (Pseudalopex culpaeus), puma (Puma concolor), striped hog-nosed skunk (Conepatus semistriatus), and Andean bear (Tremarctos ornatus)]. The two largest carnivores, puma and Andean bear, demonstrated significant threshold responses to the presence of domestic dogs at two sites. Four smaller carnivores were recorded too infrequently to model occupancy, and at least two of these species appear to be in decline. The magnitude of domestic dog impacts on native species in tropical areas like the Ecuadorian Andes currently are not recognized. Results of our study indicate that small and large carnivores are in urgent need of conservation and clearly point to dogs as a significant threat to a broad range of native species.

Setting practical conservation priorities for birds in the Western Andes of Colombia.

Science.gov (United States)

Ocampo-Peñuela, Natalia; Pimm, Stuart L

2014-10-01

We aspired to set conservation priorities in ways that lead to direct conservation actions. Very large-scale strategic mapping leads to familiar conservation priorities exemplified by biodiversity hotspots. In contrast, tactical conservation actions unfold on much smaller geographical extents and they need to reflect the habitat loss and fragmentation that have sharply restricted where species now live. Our aspirations for direct, practical actions were demanding. First, we identified the global, strategic conservation priorities and then downscaled to practical local actions within the selected priorities. In doing this, we recognized the limitations of incomplete information. We started such a process in Colombia and used the results presented here to implement reforestation of degraded land to prevent the isolation of a large area of cloud forest. We used existing range maps of 171 bird species to identify priority conservation areas that would conserve the greatest number of species at risk in Colombia. By at risk species, we mean those that are endemic and have small ranges. The Western Andes had the highest concentrations of such species-100 in total-but the lowest densities of national parks. We then adjusted the priorities for this region by refining these species ranges by selecting only areas of suitable elevation and remaining habitat. The estimated ranges of these species shrank by 18-100% after accounting for habitat and suitable elevation. Setting conservation priorities on the basis of currently available range maps excluded priority areas in the Western Andes and, by extension, likely elsewhere and for other taxa. By incorporating detailed maps of remaining natural habitats, we made practical recommendations for conservation actions. One recommendation was to restore forest connections to a patch of cloud forest about to become isolated from the main Andes. © 2014 Society for Conservation Biology.

Simulation of the electric systems of the Laguna Verde nuclear power station; Simulacion de los sistemas electricos de la Central Laguna Verde

Energy Technology Data Exchange (ETDEWEB)

Rodriguez Lozano, Saul; Ruiz Ponce, Gerardo E [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1992-03-01

In this article, the electric system models of the Laguna Verde Nuclear Power Station (CNLV) simulator, are presented. These models permit the functioning simulation, in the different operation modes of the main generator (Ruiz and Rodriguez 1991a), of the auxiliaries system and of the substation (Ruiz and Rodriguez 1991b), and of the emergency diesel generators system (Ruiz and Rodriguez 1991c). The general characteristics of such systems, considered as the basis to obtain the representative models, which were developed as modules in an independent way to be integrated in the simulator, are also described. [Espanol] En este articulo, se presenta los modelos de los sistemas electricos del simulador de la Central Laguna Verde (CLV). Estos modelos permiten simular el funcionamiento, en los diferentes modos de operacion del generador principal (Ruiz y Rodriguez, 1991a), del sistema de auxiliares y de la subestacion (Ruiz y Rodriguez, 1991b) y del sistema de generadores diesel de emergencia (Ruiz y Rodriguez, 1991c). Asimismo, se describen las caracteristicas generales de tales sistemas, consideradas como la base para obtener los modelos representativos, los cuales fueron desarrollados como modulos en forma independiente para integrarse al simulador.

Empresarios de Los Andes de la colonia a la independencia: Dos estudios de casos de Jujuy

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Viviana Conti

2009-12-01

Full Text Available El artículo estudia la trayectoria de dos empresarios de Jujuy entre la colonia y la temprana independencia: Manuel de Tezanos Pinto y Joseph de Alvarado. Ambos fueron inmigrantes del último periodo borbónico y sus vidas se cruzaron en el Potosí bajo colonial al incorporarse en la misma red de paisanaje, a partir de donde ingresarán a la misma familia por matrimonio. En este contexto, las redes y los vínculos trazados previamente fueron los que permitieron la subsistencia y reproducción de las empresas ya existentes. Se analizan vínculos mercantiles, de paisanaje, familiares y diferentes estrategias comerciales que involucraban al espacio andino y que revelan las distintas opciones que los flujos mercantiles ofrecían al sector empresarial.This paper studies the lifetime of two businessmen from Jujuy during the period between the Colony and the early Independence: Manuel de Tezanos Pinto andjosep de Alvarado. They both became immigrants in the last Borbon period and met in the late colonial Potosi when joining the same native-net; eventually, they share by marriage. In this context, it was the nets and bonds -traced previously- the ones that allowed the subsistence and reproduction of the companies already in existence. Mercantile, native-net and family bonds are analyzed along with the different commercial strategies which used to involve the Andean space and that reveal the different options that the mercantile flows offered to the business sector.

Influencia de la personalidad del cuidador/a, en los adolescentes que ejercen bullying, realizado en el nivel básico del Colegio Fiscal Mixto Central “La Inmaculada”

OpenAIRE

Cabrera Vélez, Marcela

2014-01-01

El bullying por sus características, es fundamental prevenirlo, siendo un papel importante el cual desenvuelven los cuidadores dentro del ambiente familiar, ya que según estadísticas, el Ecuador se encuentra en segundo lugar de incidencias en Sudamérica, presentándose en la Ciudad de Cuenca en un 16% a nivel escolar. El presente trabajo tiene como objetivo principal, analizar los rasgos de personalidad de los cuidadores de adolescentes que ejercen bullying pertenecientes al Colegio Central La...

Efectos de las anomalías climáticas en la cobertura de nieve de los glaciares centrales del Perú

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Jacinto Arroyo Aliaga

2015-06-01

Full Text Available Se definió como objetivo, identificar los efectos de anomalías climáticas en la cobertura de nieve de los glaciares centrales del Perú. Para el desarrollo de esta investigación se han utilizado los métodos del índice de precipitación estandarizada para el análisis de las anomalías climáticas; de la transformada rápida de Fourier para la identificación de la variabilidad climática, y el método de geoprocesamiento de imágenes satelitales Landsat. Algunos resultados son: Se identificaron cuatro anomalías negativas que corresponden a los años 1991 (extremadamente seco y 1986, 2005, 2009 (muy seco con tres anomalías positivas que corresponden a los años 1985, 2010 (extremadamente lluvioso; 1966 (muy lluvioso que influyeron en la pérdida y acumulación del manto de nieve del glaciar Huaytapallana. En el glaciar Pariaqaqa se encontró tres anomalías negativas de los años 1991 (Extremadamente seco; 1990, 2013 (muy seco y cuatro anomalías positivas de los años 1972 y 2010 (extremadamente lluvioso; 1966 y 2011 (muy lluvioso; que influyeron positivamente en la acumulación del manto de ieve. Se concluye que la pérdida neta corresponde a 5 km2 en el glaciar Huaytapallana y 7 km2 en el glaciar Pariaqaqa. El incremento del manto de nieve del glaciar Huaytapallana y Pariaqaqa en los ciclos hidrológicos del 2010, 2011 y 2012 se debe a un aumento en las intensidades de las precipitaciones registradas durante estos años por cambios en los patrones de circulación atmosférica por fenómenos de El Niño Oscilación del Sur.

Los centros de gravedad de la Web

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Sandra González-Bailón

2009-12-01

Full Text Available El acceso a información en la Web no es independiente de la estructura de red que forman los enlaces entre páginas y dominios. Los buscadores reconstruyen mapas de esas conexiones para identificar los recursos más centrales y darles prioridad en sus algoritmos. Sin embargo, la estructura de la Web no responde sólo a la calidad de los contenidos.

La región de los Andes: una visión general y una propuesta de investigación La región de los Andes: una visión general y una propuesta de investigación

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Miroslawa Czerny

2009-12-01

Full Text Available This paper refers to the unevenness on the quality of life originated by the environmental settings that are calibrated by the different human activities on the natural systems. We emphasize the issue of vulnerability of the poorest societies, looking for explanations that support that condition and the social responsibility of administrators to change those inequalities.Este artículo se refiere a las desigualdades de calidad de vida que se originan en las ofertas ambientarles y se calibran por las diferentes actuaciones humanas en los sistemas naturales. Se toca el tema de la vulnerabilidad de las sociedades más pobres, buscando explicaciones que mantienen esa condición y la responsabilidad social de los administradores para cambiar estas desigualdades.

Efecto insecticida de los aceites esenciales de algunas lamiáceas sobre Tecia solanivora Povolny en condiciones de laboratorio

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Ramìrez julian Ernesto

2010-08-01

Full Text Available La papa, el producto agrícola más importante en la economía de
los andes colombianos, tiene en la polilla guatemalteca (Tecia
solanivora Povolny su principal plaga, cuyo control se basa en
el uso intensivo de plaguicidas. Una alternativa potencial a la
aplicación de estos insumos es el uso de productos vegetales.
En condiciones controladas, el presente trabajo evaluó el efecto
de los aceites esenciales de Ocimum basilicum, O. majorana,
M. piperita, O. vulgare, P. cablin, R. officinalis, S. officinalis y
T. vulgaris sobre los huevos, larvas y adultos de T. solanivora
al ser aplicados directamente sobre los tubérculos, y sobre la
superficie del suelo. No se encontró ningún efecto de los tratamientos
sobre el desarrollo larval ni sobre la longevidad de
los adultos. En las dos modalidades de aplicación estudiadas,
los aceites de P. cablin y T. vulgaris en una concentración del
0,25% produjeron una reducción significativa en la viabilidad
de los huevos. Al aumentar la humedad del suelo y el volumen
de aplicación de los aceites, los aceites de O. basilicum, O.
majorana, M. piperita, R. officinalis también tuvieron acción
ovicida. Estos resultados son evidencia del potencial de estos
aceites como controladores de Tecia solanivora.

Plagas chupadoras de las cítricas (naranjo, limonero, mandarina) en los andes venezolanos.

OpenAIRE

Briceño Vergara, Armando J.

2007-01-01

Editorial. Suniaga Q., José La codorniz fuente proteica para consumo humano. Díaz Cuellar, Doraida R. y González, Diomary Diagnóstico de parásitos gastrointestinales en bovinos y su importancia en la productividad de los sistemas ganaderos. Castillo O., Mayela; Hernández, Javier A.; Betancourt, Arquímedes y Suniaga Q., José Nutrición vegetal (II). Moyeja Santana, Juan de Jesús Nutrición vegetal (III). Moyeja Santana, Juan de Jesús Plagas chupadoras de las cítrica...

Central Bank independence in Latin America La independencia de la Banca Central en América Latina

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Junguito Bonnet Roberto

1996-06-01

Full Text Available This article describes the origin and evolution of the central banks of Argentina, Brazil, Chile, Colombia, Mexico, and Venezuela, and analyzes their respective institutional structures. It also studies the contribution of the central bank to stabilization and the problems for maintaining this independence into the future.Este artículo describe el origen y la evolución de los Bancos Centrales de Argentina, Brasil, Chile, Colombia, México y Venezuela, y analiza sus respectivas estructruras institucionales. También estudia la contribución de la banca central a la estabilización y los problemas para que esta independencia se mantenga en el futuro.

Caracterización composicional de los depósitos arenosos actuales generados en el Sistema Central

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Arribas, J.

1989-08-01

Full Text Available In this work we have studied the light mineral fraction of modern sands derived from single source lithologies (plutonic, gneissic or slate-schists in the Sistema Central (Central Spain. In this way we can analize the control of the source area lithology in sand composition. First we pay attention on tbe control of grain size sand in composition. Rock fragments decrease when grain size decreases. However, the amount of feldspar increases due to its low mechanical stability. Thus, the K/P index (K-feldspar/plagioclases is highly variable with grain size, because the different mechanical stabilities of both minerals. The trends of the amounts of components in relation with grain size are very similar, in a11 deposits. However, each percentages vary markedly between source areas with different lithologies. The projection area of the studied sands in a QFFR díagram is highly controled by grain size and lithology of source area. Thus, sands derived from slate-schists lithology appear near QFR fringe in a11 grain size fractions. Sands derived from plutonic or gneissic rocks have a high dispersion in the diagram, fram FR pole to QF fringe, depending on grain size of the sand. We conclude that the use of a single sand size fraction (0,5-0,25 mm to provenance analysis permits to discrimine source lithologies, but with a 1055 of information about global deposit compositionSe caracteriza composicionalmente la fracción ligera arenosa de los depósitos detríticos actuales generados en zonas de cabecera de arroyos que drenan macizos del Sistema Central con distintas litologías (plutónicas, gnéisicas o pizarras-esquistos. Dicha caracterización se ha basado en el análisis petrográfico de las muestras recogidas. Este análisis se ha efectuado, en cada muestra, en cinco fracciones de tamaño con intervalos de l ̣Ǿ entre 2 mm y 0,062 mm. De este modo se estudia el control que ejercen tanto la litología del área fuente como el tamaño de grano en

Cloeodes incus (Waltz & McCafferty (Ephemeroptera: Baetidae: first record for Argentina, hydrologic and environmental remarks

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Marcela A. DE PAUL

2013-01-01

Full Text Available Cloeodes incus se cita por primera vez para la Argentina. Se recolecta - ron ninfas mediante red Surber y red de arrastre en los Ríos Pircas y Ajedrez (Jujuy: Rinconada en altitudes superiores a los 4000 msnm. Se realizaron dos campañas anuales: fin de estación lluviosa (abril y fin de estación seca (noviembre, durante los años 2011 y 2012. Este estudio permite ampliar la distribución de C. incus en los Andes Centrales e incorporar información hidrológica y ambiental de los sitios se - leccionados. Los mayores valores de densidad se obtuvieron al final de la estación seca, con escasa cantidad de agua y con un pH de 7,1 – 8,1. Su presencia también fue registrada, aguas abajo de actividades mineras, con un pH de 3,7.

Tectonostratigraphic reconstruction Cretaceous volcano-sedimentary in the northwestern Andes: from extensional tectonics to arc accretion.

Science.gov (United States)

Zapata, S.; Patino, A. M.; Cardona, A.; Mejia, D.; Leon, S.; Jaramillo, J. S.; Valencia, V.; Parra, M.; Hincapie, S.

2014-12-01

Active continental margins characterized by continuous convergence experienced overimposed tectonic configurations that allowed the formation of volcanic arcs, back arc basins, transtensional divergent tectonics or the accretion of exotic volcanic terranes. Such record, particularly the extensional phases, can be partially destroyed and obscure by multiple deformational events, the accretion of exotic terranes and strike slip fragmentation along the margin. The tectonic evolution of the northern Andes during the Mesozoic is the result of post Pangea extension followed by the installation of a long-lived Jurassic volcanic arc (209 - 136 ma) that apparently stops between 136 Ma and 110 Ma. The Quebradagrande Complex has been define as a single Lower Cretaceous volcano-sedimentary unit exposed in the western flank of the Central Cordillera of the Colombian Andes that growth after the Late Jurassic to Early Cretaceous magmatic hiatus. The origin of this unit have been related either to an oceanic volcanic arc or a marginal basin environment. The existence of such contrasting models reflect the regional perspective followed in published studies and the paucity of detail analysis of the volcano-sedimentary sequences.We integrate multiple approaches including structural mapping, stratigraphy, geochemistry, U-Pb provenance and geochronology to improve the understanding of this unit and track the earlier phases of accumulation that are mask on the overimposed tectonic history. Our preliminary results suggest the existence of different volcano-sedimentary units that accumulated between 100 Ma and 82 Ma.The older Lower Cretaceous sequences was deposited over Triassic metamorphic continental crust and include a upward basin deepening record characterized by thick fan delta conglomerates, followed by distal turbidites and a syn-sedimentary volcanic record at 100 ma. The other sequence include a 85 - 82 Ma fringing arc that was also formed close to the continental margin or

Nuclear Data for Safe Operation and Waste Transmutation: ANDES (Accurate Nuclear Data for nuclear Energy Sustainability); Datos nucleares para la operacion segura y la transmutacion de residuos: Andes (Datos Nucleares Precisos para la Sostenibilidad de la Energia Nuclear)

Energy Technology Data Exchange (ETDEWEB)

Gonzalez, E. M.

2014-07-01

Nuclear research within the 7th Framework Program (FP7 and FP7+2) of EURATOM has devoted a significant fraction of its efforts to the development of advanced nuclear fuel cycles and reactor concepts, mainly fast reactors, aiming to improve the long term sustainability by reduction of the final wastes, optimal use of natural resources and improvement of safety in the present and future nuclear installations. The new design need more accurate basic nuclear data for isotopes, like minor actinides, potentially playing an important role in the operation, fuel concept, safety or final wastes of those reactors and fuel cycles. Four projects, ANDES, ERINDA, EUFRAT and CHANDA, supported by EURATOM within the FP7 and FP7+2, have put together most of the European Nuclear Data community to respond efficiently and in a coordinated way to those needs. This paper summarizes the objectives, and main achievements of ANDES, the project responsible for most of the measurements and technical achievements that was coordinated by CIEMAT. Indeed, CIEMAT has coordinated the nuclear data R and D projects within EURATOM during the last 7 years (NUDATRA domain of EUROTRANS, and ANDES) and will continue this coordination in the CHANDA project till 2017. (Author)

Mammalian carnivore occupancy is inversely related to presence of domestic dogs in the high Andes of Ecuador.

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Galo Zapata-Ríos

Full Text Available Although the Andes have long been occupied by people, habitat loss, fragmentation through deforestation, and other human activities such as introduction of invasive species have increased drastically during the past century. The Ecuadorian Andes are considered a biodiversity hotspot. However, the fauna and threats to the region are poorly studied, and understanding of factors that shape the distribution of species in habitats disturbed by human activities is needed to identify and mitigate region-wide threats to wildlife. We evaluated factors associated with patterns of occurrence of Andean carnivores in landscapes of the northern Ecuadorian Andes, particularly habitat loss, fragmentation, and occupancy of domestic dogs, and determined whether thresholds occurred for these factors beyond which carnivore occurrence declined markedly. Five study areas (each 20 x 20 km were surveyed with a total effort of 2,800 camera trap nights. Occupancies of four of the eight carnivores known from the region were best predicted by occupancy of domestic dogs rather than measures of habitat loss and fragmentation [Andean fox (Pseudalopex culpaeus, puma (Puma concolor, striped hog-nosed skunk (Conepatus semistriatus, and Andean bear (Tremarctos ornatus]. The two largest carnivores, puma and Andean bear, demonstrated significant threshold responses to the presence of domestic dogs at two sites. Four smaller carnivores were recorded too infrequently to model occupancy, and at least two of these species appear to be in decline. The magnitude of domestic dog impacts on native species in tropical areas like the Ecuadorian Andes currently are not recognized. Results of our study indicate that small and large carnivores are in urgent need of conservation and clearly point to dogs as a significant threat to a broad range of native species.

Apatite fission-track dating of erosion in the eastern Andes, Bolivia

International Nuclear Information System (INIS)

Crough, S.T.

1983-01-01

Three samples from a Triassic-age batholith in the eastern Andes northeast of La Paz, Bolivia yield apatitic fission-track ages of 11-13 Ma. Interpreting these young ages as due to uplift and erosion requires approximately 2.5-5.0 km of erosion in the past 12 Ma, an amount which is consistent with the known geology and which is typical of many active mountain ranges. (orig.)

Definição das trajetórias P-T-t em rochas metamórficas do flanco ocidental da Cordilheira Central da Colômbia, nas regiões de Caldas e El Retiro

OpenAIRE

Andres Bustamante Londoño

2003-01-01

Apesar da existência de vários estudos geológicos detalhados no segmento norte do Andes, muitos aspectos estão ainda por serem resolvidos, principalmente aqueles concernentes ao tipo, grau e evolução metamórfica, ambiente tectônico de formação e correlação com margem paleozóica do continente Gondwana e com os terrenos mesozóicos oceânicos. A Cordilheira Central dos Andes Colombianos, é representada por um complexo polimetamórfico com magmatismo associado e uma fina pilha de sedimentos supraja...

Millennial-scale vegetation changes in the tropical Andes using ecological grouping and ordination methods

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Urrego, D.H.; Hooghiemstra, H.; Rama-Corredor, O.; Martrat, B.; Grimalt, J.O.; Thompson, L.; Bush, M.B.; González-Carranza, Z.; Hanselman, J.; Valencia, B.; Velásquez-Ruiz, C.

2016-01-01

We compare eight pollen records reflecting climatic and environmental change from northern and southern sites in the tropical Andes. Our analysis focuses on the last 30 000 years, with particular emphasis on the Pleistocene to Holocene transition. We explore ecological grouping and downcore

Calculated WIMP signals at the ANDES laboratory: comparison with northern and southern located dark matter detectors

Science.gov (United States)

Civitarese, O.; Fushimi, K. J.; Mosquera, M. E.

2016-12-01

Weakly interacting massive particles (WIMPs) are possible components of the Universe’s dark matter (DM). The detection of WIMPs is signaled by the recoil of the atomic nuclei which form a detector. CoGeNT at the Soudan Underground Laboratory (SUL) and DAMA at the Laboratori Nazionali del Gran Sasso (LNGS) have reported data on annual modulation of signals attributed to WIMPs. Both experiments are located in laboratories in the Northern Hemisphere. DM detectors are planned to operate (or already operate) in laboratories in the Southern Hemisphere, including SABRE at Stawell Underground Physics Laboratory (SUPL) in Australia, and DM-ICE in Antarctica. In this work we have analyzed the dependence of diurnal and annual modulation of signals, pertaining to the detection of WIMP, on the coordinates of the laboratory, for experiments which may be performed in the planned new Agua Negra Deep Experimental Site (ANDES) underground facility, to be built in San Juan, Argentina. We made predictions for NaI and Ge-type detectors placed in ANDES, to compare with DAMA, CoGeNT, SABRE and DM-ICE arrays, and found that the diurnal modulation of the signals, at the ANDES site, is amplified at its maximum value, both for NaI (Ge)-type detectors, while the annual modulation remains unaffected by the change in coordinates from north to south.

Calculated WIMP signals at the ANDES laboratory: comparison with northern and southern located dark matter detectors

International Nuclear Information System (INIS)

Civitarese, O; Mosquera, M E; Fushimi, K J

2016-01-01

Weakly interacting massive particles (WIMPs) are possible components of the Universe’s dark matter (DM). The detection of WIMPs is signaled by the recoil of the atomic nuclei which form a detector. CoGeNT at the Soudan Underground Laboratory (SUL) and DAMA at the Laboratori Nazionali del Gran Sasso (LNGS) have reported data on annual modulation of signals attributed to WIMPs. Both experiments are located in laboratories in the Northern Hemisphere. DM detectors are planned to operate (or already operate) in laboratories in the Southern Hemisphere, including SABRE at Stawell Underground Physics Laboratory (SUPL) in Australia, and DM-ICE in Antarctica. In this work we have analyzed the dependence of diurnal and annual modulation of signals, pertaining to the detection of WIMP, on the coordinates of the laboratory, for experiments which may be performed in the planned new Agua Negra Deep Experimental Site (ANDES) underground facility, to be built in San Juan, Argentina. We made predictions for NaI and Ge-type detectors placed in ANDES, to compare with DAMA, CoGeNT, SABRE and DM-ICE arrays, and found that the diurnal modulation of the signals, at the ANDES site, is amplified at its maximum value, both for NaI (Ge)-type detectors, while the annual modulation remains unaffected by the change in coordinates from north to south. (paper)

Los sistemas geotermales del Pirineo Central. II. Resultados de la aplicación de técnicas geotermométricas

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Gimeno, M. J.

1997-04-01

Full Text Available Reservoir temperatures are calculated for six geothermal systems in the Central Pyrenees (Arties, Caldas de Bohí, Benasque, Panticosa, Luchon and Cauterets using different geothermometrical methods. In general, the selected hot springs have similar geochemical features belonging to the group of alkaline thermal systems installed in granitic environments. More in detail, however, it is important to note that Na and K concentrations of Panticosa and Benasque thermal springs are the lowest found in this water group to date. Both classical geothermometers and modeling calculations agree within a few degrees for the Arties, Caldas and Luchon geothermal systems: thermal waters are in equilibrium in their reservoirs with a common mineral association (quartz, albite, K-feldspar, caolinite and some calc-aluminum silicate at 103, 107 and 127° C, respectively. Cauterets, Panticosa and Benasque thermal waters appear to be equilibrated with the same mineral association at 98, 107 and 94° C, respectively as deduced from silica and Na-K geothermometers. Na-K-Ca and Ca-K geothermometers provide lower temperatures for these systems, probably because of some exchange of calcium between rock and water during the ascent of solutions. Nevertheless, the modeling calculations fail to represent the composition of Panticosa and Benasque thermal springs: these waters are out of equilibrium with the selected mineral association at the temperatures given by Na-K and SiO2-quartz geothermometers Therefore, the agreement between these geothermometers appear to be fortuitous, specially for Benasque thermal waters.Mediante la utilización de distintas técnicas geotermométricas se han estimado las temperaturas en el reservorio de seis sistemas geotermales (Arties, Caldas de Bohí, Benasque, Panticosa, Luchon y Cauterets instalados en los materiales graníticos del Pirineo Central. Los manantiales seleccionados para realizar los cálculos muestran similares caracteres

A modelling study of the seasonal snowpack energy balance at three sites along the Andes Cordillera. Regional climate and local effects.

Science.gov (United States)

McPhee, James; Mengual, Sebastian; MacDonell, Shelley

2017-04-01

Seasonal snowpack melt constitutes the main water source for large portions of extratropical South America, including central Chile and Western Argentina. The properties and distribution of snow in the Andes are threatened by rapid climate change, characterised by warming and drying. This study provides a first attempt at detailed description of the energy balance of the seasonal snowpack and its variability along a latitudinal gradient, which is also correlated with an elevation and precipitation gradient, in the Andes Cordillera. The Snowpack model was validated at semi-arid, Mediterranean and temperate humid sites, where meteorological and snowpack properties have been observed since year 2013. Site elevations decrease from north to south, whereas precipitation climatology increases with latitude. Results show that turbulent energy exchange becomes relatively more important in periods of low snow accumulation, with sensible heat fluxes having a greater effect in cooling the snowpack at the high-altitude, low latitude site. Likewise, daily melt-freeze cycles are important in maintaining positive cold contents throughout the accumulation season at this site, and contribute to extending the duration of snow cover despite low accumulation and high radiation loads. In contrast, the southernmost, lowest elevation site shows smaller daily temperature amplitude and a much more preponderant radiation component to the energy balance. This modelling exercise highlights the nonlinearities of snow dynamics at different geographical settings in a sparsely monitored mountain area of the world, as well as the need for further understanding in order to evaluate the sensitivity of snow-dominated watersheds to global warming and climate change.

Macroinvertebrate community response to acid mine drainage in rivers of the High Andes (Bolivia).

NARCIS (Netherlands)

Damme, P.A. van; Hamel, C.; Ayala, A.; Bervoets, L.

2008-01-01

Several High Andes Rivers are characterized by inorganic water pollution known as acid mine drainage (AMD). The aim of this study was to assess the relationship between metal concentrations in the sediments and the macroinvertebrate communities in two river basins affected by AMD. In general, the

Cenozoic basin thermal history reconstruction and petroleum systems in the eastern Colombian Andes

Science.gov (United States)

Parra, Mauricio; Mora, Andres; Ketcham, Richard A.; Stockli, Daniel F.; Almendral, Ariel

2017-04-01

Late Mesozoic-Cenozoic retro-arc foreland basins along the eastern margin of the Andes in South America host the world's best detrital record for the study of subduction orogenesis. There, the world's most prolific petroleum system occur in the northernmost of these foreland basin systems, in Ecuador, Colombia and Venezuela, yet over 90% of the discovered hydrocarbons there occur in one single province in norteastern Venezuela. A successful industry-academy collaboration applied a multidisciplinary approach to the study of the north Andes with the aim of investigating both, the driving mechanisms of orogenesis, and its impact on hydrocarbon accumulation in eastern Colombia. The Eastern Cordillera is an inversion orogen located at the leading edge of the northern Andes. Syn-rift subsidence favored the accumulation of km-thick organic matter rich shales in a back-arc basin in the early Cretaceous. Subsequent late Cretaceous thermal subsidence prompted the accumulation of shallow marine sandstones and shales, the latter including the Turonian-Cenomanian main hydrocarbon source-rock. Early Andean uplift since the Paleocene led to development of a flexural basin, filled with mainly non-marine strata. We have studied the Meso-Cenozoic thermal evolution of these basins through modeling of a large thermochronometric database including hundreds of apatite and zircon fission-track and (U-Th)/He data, as well as paleothermometric information based on vitrinite reflectance and present-day temperatures measured in boreholes. The detrital record of Andean construction was also investigated through detrital zircon U-Pb geochronometry in outcrop and borehole samples. A comprehensive burial/exhumation history has been accomplished through three main modeling strategies. First, one-dimensional subsidence was used to invert the pre-extensional lithospheric thicknesses, the magnitude of stretching, and the resulting heat flow associated to extension. The amount of eroded section and

Primer registro del ratón colombiano del bosque Chilomys instans (Cricetidae: Rodentia en Cajamarca: actualizando el listado de mamíferos del Perú

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César E. Medina

2016-12-01

Full Text Available El roedor Chilomys instans (Thomasomyini, Cricetidae es una especie común en la comunidad de mamíferos que habita los Andes del Norte en Sudamérica. Aquí presentamos el primer registro de la especie para el Perú, en base a la revisión morfológica de tres ejemplares colectados en el departamento de Cajamarca (Andes del Centro. Se presentan comentarios sobre la taxonomía de C. instans e información sobre su historia natural. La amplia distribución del género Chilomys en los Andes pone de manifiesto la necesidad de realizar la revisión taxonómica de éste género para esclarecer los límites de las especies que la conforman.

A glacial record of the last termination in the southern tropical Andes

Science.gov (United States)

Bromley, G. R.; Schaefer, J. M.; Winckler, G.; Hall, B. L.; Todd, C. E.; Rademaker, K.

2012-12-01

The last glacial termination represents the highest-magnitude climate change of the last hundred thousand years. Accurate resolution of events during the termination is vital to our understanding of how - and why - the global climate system transitions from a full glacial to interglacial state, as well as the causes of abrupt climate change during the late-glacial period. Palaeoclimate data from low latitudes, though relatively sparse, are particularly valuable, since the tropical ocean and atmosphere likely play a crucial role in Quaternary climate variability on all timescales. We present a detailed glacier record from the Andes of southern Peru (15°S), resolved with 3He surface-exposure dating and spanning the last glacial maximum and termination. Our dataset reveals that glaciers in this part of the Southern Hemisphere maintained their Late Pleistocene maxima for several millennia and that the onset of the termination may have occurred relatively late. Deglaciation was punctuated by two major advances during the late-glacial period. Following the glacial-interglacial transition, our preliminary chronologic and morphologic data suggest that, in contrast to the Northern Hemisphere, glaciers in the southern tropical Andes have experienced overall shrinkage during the Holocene.

A new genus of Platynini (Coleoptera: Carabidae) from Argentina

OpenAIRE

ROIG-JUÑENT, Sergio

2003-01-01

Los Platynini constituyen un grupo de carábidos distribuidos ampliamente en América del Sur, existiendo la mayor diversidad de especies en las regiones tropicales de altura de Los Andes. En la Argentina y Chile, la mayoría de las especies de Platynini se hallan distribuidas en áreas extracordilleranas, conociéndose pocos datos para la región Andina. A partir de recolecciones realizadas en la Precordillera y Cordillera de los Andes en Mendoza (Argentina), se hallaron ejemplares pertenecientes ...

A TRAVÉS DE LOS ANDES. ESTRATEGIAS SOCIALES Y REDES DE PODER ENTRE CÓRDOBA Y HUANCAVELICA EN EL SIGLO XVIII

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Mar\\u00EDa Victoria M\\u00E1rquez

2012-01-01

Full Text Available Se indaga en la participación y los usos de los espacios burocráticos y administrativos por parte de la élite colonial en el siglo XVIII. Para ello se aborda el caso de una familia de grandes tratantes del comercio interregional- los Mendiolaza- cuyos intereses se asentaron en diversos puntos de la región andina. Así se propone una mirada comparativa sobre las estrategias de un mismo entramado social o red de relaciones. El artículo hace foco en dos lugares, Córdoba y Huancavelica, en tanto se trata de ámbitos nucleares en la actividad de esta familia, pero también, de regiones contrastantes cuyas realidades escasamente podrían paragonarse: Córdoba una jurisdicción de frontera, dedicada mayormente a la ganadería mular y ubicada lejos de los principales centros del poder colonial; Huancavelica, una ciudad minera, bajo jurisdicción real por ser la única zona productora de mercurio americano y sometida a la influencia y los intereses de la corte virreinal de Lima. Se constata el establecimiento de alianzas matrimoniales, compadrazgos y amistades que configuraron estrategias de poder tan eficaces como el ejercicio mismo de un oficio en la administración colonial. Asimismo se establece, para el caso específico abordado, que el apoyo sistemático a las controvertidas medidas borbónicas- y a sus funcionarios- fue un aspecto esencial para su propia consolidación, dentro de los espacios de poder locales en los que se avecindaron.

Drunken Speech and the Construction of Meaning: Bilingual Competence in the Southern Peruvian Andes.

Science.gov (United States)

Harvey, Penelope M.

1991-01-01

Examination of the language use of drunken speakers in a bilingual Southern Peruvian Andes community found that drunken speakers were less constrained in their linguistic choices by individual linguistic competence and of differential status between speaker and addressee, and they exploited the ambiguities in implicit social meanings that normally…

COLUMNEA RANGELII (GESNERIACEAE, A NEW SPECIES FROM THE SERRANÍA DE LOS PARAGUAS IN THE COLOMBIAN ANDES

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Amaya Marisol

2012-06-01

Full Text Available A new species of Columnea belonging to the section Collandra (Gesneriaceae from La Serranía de los Paraguas in the Department of Valle del Cauca (Cordillera Occidental, Colombia, is described and illustrated.

Amalgamation and small-scale gold mining in the ancient Andes

OpenAIRE

Brooks, William E.; Schwörbel, Gabriela; Castillo, Luis Enrique

2013-01-01

In 1532, the volume of gold provided by Atahualpa, the Inka king, as ransom for his release from the Spanish was hard evidence for the efficient small-scale gold mining that took place before European contact and the number of gold occurrences in the Andes. At Huancavelica, Perú, mercury occurs as a native metal and as cinnabar [HgS], which was used for pigments, funeral preparations, and retorted to obtain mercury. Using Inductively Coupled Plasma analysis (ICP), an average of 15 ppm (parts...

Dinámica del carbono en los ecosistemas de páramo de los Andes neotropicales: revisión de literatura sobre modelos y parámetros relevantes

NARCIS (Netherlands)

Sevink, J.; Tonneijck, F.H.; Kalbitz, K.; Cammeraat, L.H.; Cuesta, F.; Sevink, J.; Llambí, L.D.; De Bièvre, B.; Posner, J.

2014-01-01

Resumen Los suelos del páramo almacenan cantidades excepcionales de carbono debido a las condiciones edáficas y climáticas sobre las cuales se desarrollan. Este gran reservorio de carbono está amenazado debido a los efectos del cambio climático y las dinámicas de uso de la tierra. No obstante, el

Geodynamic controls on the contamination of Cenozoic arc magmas in the southern Central Andes: Insights from the O and Hf isotopic composition of zircon

Science.gov (United States)

Jones, Rosemary E.; Kirstein, Linda A.; Kasemann, Simone A.; Dhuime, Bruno; Elliott, Tim; Litvak, Vanesa D.; Alonso, Ricardo; Hinton, Richard

2015-09-01

Subduction zones, such as the Andean convergent margin of South America, are sites of active continental growth and crustal recycling. The composition of arc magmas, and therefore new continental crust, reflects variable contributions from mantle, crustal and subducted reservoirs. Temporal (Ma) and spatial (km) variations in these contributions to southern Central Andean arc magmas are investigated in relation to the changing plate geometry and geodynamic setting of the southern Central Andes (28-32° S) during the Cenozoic. The in-situ analysis of O and Hf isotopes in zircon, from both intrusive (granitoids) and extrusive (basaltic andesites to rhyolites) Late Cretaceous - Late Miocene arc magmatic rocks, combined with high resolution U-Pb dating, demonstrates distinct across-arc variations. Mantle-like δ18O(zircon) values (+5.4‰ to +5.7‰ (±0.4 (2σ))) and juvenile initial εHf(zircon) values (+8.3 (±0.8 (2σ)) to +10.0 (±0.9 (2σ))), combined with a lack of zircon inheritance suggests that the Late Cretaceous (∼73 Ma) to Eocene (∼39 Ma) granitoids emplaced in the Principal Cordillera of Chile formed from mantle-derived melts with very limited interaction with continental crustal material, therefore representing a sustained period of upper crustal growth. Late Eocene (∼36 Ma) to Early Miocene (∼17 Ma) volcanic arc rocks present in the Frontal Cordillera have 'mantle-like' δ18O(zircon) values (+4.8‰ (±0.2 (2σ) to +5.8‰ (±0.5 (2σ))), but less radiogenic initial εHf(zircon) values (+1.0 (±1.1 (2σ)) to +4.0 (±0.6 (2σ))) providing evidence for mixing of mantle-derived melts with the Late Paleozoic - Early Mesozoic basement (up to ∼20%). The assimilation of both Late Paleozoic - Early Mesozoic Andean crust and a Grenville-aged basement is required to produce the higher than 'mantle-like' δ18O(zircon) values (+5.5‰ (±0.6 (2σ) to +7.2‰ (±0.4 (2σ))) and unradiogenic, initial εHf(zircon) values (-3.9 (±1.0 (2σ)) to +1.6 (±4.4 (2�

Validación del Cuestionario de Creencias Centrales de los Trastornos de la Personalidad (CCE-TP en población colombiana

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Nora Helena Londoño A.

2010-07-01

Full Text Available Se construyó un cuestionario para evaluar creencias centrales asociadas con los trastornos de la personalidad, fundamentadas en el Modelo de la Terapia Cognitiva. Se realizó el análisis estructural y la validez de contenido de la prueba en población universitaria de la ciudad de Medellín, Colombia. La muestra fue representativa y elegida al azar a través de un procedimiento polietápico. Un número de 809 estudiantes universitarios contestaron el cuestionario de creencias centrales de los trastornos de la personalidad (CCE-TP. Se realizó un análisis factorial exploratorio de la prueba, reagrupándose los ítems en 14 factores (F que representan el 61,3% de la varianza. F1: CCE-TP antisocial (8 ítems, a 0,839; F2: CCE-TP esquizotípico/límite (8 ítems, a 0,846; F3: CCE-TP histriónico/patrón seductor (6 ítems, a 0,833; F4: CCE-TP paranoide (6 ítems, a 0,836; F5: CCE-TP por evitación / autopercepción negativa (5 ítems, a 0,755; F6: CCE-TP por dependencia (5 ítems, a 0,797; F7: CCE-TP histriónico/ dependencia emocional (4 ítems, a 0,755; F8: CCETP obsesivo-compulsivo/perfeccionista (4 ítems, a 0,808; F9: CCE-TP por evitación/hipersensible (4 ítems, a 0,766; F10: CCE-TP obsesivo-compulsivo/ crítico frente a los demás (3 ítems, a 0,851; F11: CCE-TP narcisista (4 ítems, a 0,717; F12: CCE-TP pasivo-agresivo / temor a ser dominado (3 ítems, a 0,719; F13: CCE-TP pasivo-agresivo/crítico frente a la autoridad (3 ítems, a 0,685, y F14: CCE-TP esquizoide (2 ítems, a 0,774. El alfa de Cronbach de la prueba fue de 0,931.

Validación del Cuestionario de Creencias Centrales de los Trastornos de la Personalidad (CCE-TP en población colombiana

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Diego Castrillón M.

2007-06-01

Full Text Available Se construyó un cuestionario para evaluar creencias centrales asociadas con los trastornos de la personalidad, fundamentadas en el Modelo de la Terapia Cognitiva. Se realizó el análisis estructural y la validez de contenido de la prueba en población universitaria de la ciudad de Medellín, Colombia. La muestra fue representativa y elegida al azar a través de un procedimiento polietápico. Un número de 809 estudiantes universitarios contestaron el cuestionario de creencias centrales de los trastornos de la personalidad (CCE-TP. Se realizó un análisis factorial exploratorio de la prueba, reagrupándose los ítems en 14 factores (F que representan el 61,3% de la varianza. F1: CCE-TP antisocial (8 ítems, a 0,839; F2: CCE-TP esquizotípico/límite (8 ítems, a 0,846; F3: CCE-TP histriónico/patrón seductor (6 ítems, a 0,833; F4: CCE-TP paranoide (6 ítems, a 0,836; F5: CCE-TP por evitación / autopercepción negativa (5 ítems, a 0,755; F6: CCE-TP por dependencia (5 ítems, a 0,797; F7: CCE-TP histriónico/dependencia emocional (4 ítems, a 0,755; F8: CCETP obsesivo-compulsivo/perfeccionista (4 ítems, a 0,808; F9: CCE-TP por evitación/hipersensible (4 ítems, a 0,766; F10: CCE-TP obsesivo-compulsivo/ crítico frente a los demás (3 ítems, a 0,851; F11: CCE-TP narcisista (4 ítems, a 0,717; F12: CCE-TP pasivo-agresivo / temor a ser dominado (3 ítems, a 0,719; F13: CCE-TP pasivo-agresivo/crítico frente a la autoridad (3 ítems, a 0,685, y F14: CCE-TP esquizoide (2 ítems, a 0,774. El alfa de Cronbach de la prueba fue de 0,931.

Diagnóstico de clima organizacional. Caso de estudio: Universidad de Los Andes–Táchira “Dr. Pedro Rincón Gutiérrez”

OpenAIRE

Rangel Rangel, Milagros; Castro de Bustamante, Jeannett

2013-01-01

El objetivo de la presente investigación se orienta a diagnosticar el Clima Organizacional predominante en la Universidad de Los Andes “Dr. Pedro Rincón Gutiérrez. Con esta finalidad, y asumiendo una posición de complementariedad de métodos y técnicas de carácter cuantitativo y cualitativo, se aplicó una adaptación del Cuestionario de Clima Organizacional de Litwin y Stringer (1968) a una muestra de 47 docentes seleccionados por muestreo estratificado simple. Complementariam...

La interacción de los usuarios en los perfiles de Facebook de la prensa española

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María Merino-Bobillo

2013-01-01

Full Text Available El auge de las redes sociales ha llevado a la prensa a utilizar estos nuevos canales de comunicación como un medio para interactuar con los usuarios. Interesa conocer el uso que los periódicos realizan y la respuesta de sus seguidores. Por tanto, el estudio se centra en analizar los perfiles en Facebook de los diarios de mayor tirada en España durante el trimestre de octubre a diciembre de 2012. Los ejes centrales del artículo están orientados en dos direcciones: uno tiene que ver con el uso de la red social por parte de los diarios estudiados y el otro con la interacción de los usuarios.

Analogue modeling of rotational orogenic wedges: implications for the Neogene structural evolution of the Southern Central Andes (33°-35°S)

Science.gov (United States)

Herrera, S. S.; Farías, M.; Pinto, L.; Yagupsky, D. L.; Guzman, C.; Charrier, R.

2017-12-01

Structural evolution of the southernmost Central Andes is a major subject of debate. Overall vergence within the range and how intra-continental subduction prompts Andean orogeny are controversial topics. Between 33°-35° S, strike of the western slope main structures shifts southwards, from N-S to NNE-SSW, defining the Maipo Orocline. Likely, width of the Principal Cordillera increases southwards. Despite, a progressive southward decrease in orogenic volume has been determined for the segment. To understand such latitudinal variations, and to provide explanations for overall vergence, we carry out analogue models of contractional wedges to explore upper-crustal thrust system development with a progressive variation of the convergence vector. The model setup consisted of a fixed plate on which a mobile plate generated a velocity discontinuity. The upper-crust was simulated using low-cohesive quartz sand. The mobile plate was fixed at its northern end to a pivot, thus progressively incrementing shortening and the obliquity of convergence southwards. PIV photogrammetry recorded wedge evolution. A classical doubly-vergent wedge was formed, consisting of a steep 35° dipping, static thrust on the retro-side, an uplifted core, and an incipient forward-breaking, 25° critically tapered imbricated thrust fan on the pro-side, wider (in plan-view) where the imposed shortening reached the maximum. The resulting wedge is reminiscent of: the steep western Andean slope, in which the bordering thrust has maintained its present position during the Neogene; and the east-vergent fold-and-thrust belt of the eastern slope. The asymmetrical doubly vergence of the model suggests west-directed subduction of the South American continent beneath the orogen. The southward width increase is geometrically comparable to the natural analogue, yet we observe a flat contrast with orogenic shortening and volume estimates for the region. This can be attributed to the fact that uplift and erosion

Racialization of the Bilingual Student in Higher Education: A Case from the Peruvian Andes

Science.gov (United States)

Zavala, Virginia

2011-01-01

In the Andes, a phonological transference known as "motoseo" has acquired ideological weight. People think that bilingual speakers of Quechua and Spanish "confuse" the vowels when speaking Spanish and that they are inferior to the ones who do not. In this article, I analyze the ideological agenda of the racialized verbal…

INFLUENCIA DE LOS ESTILOS DE COMUNICACIÓN ASERTIVA DE LOS DOCENTES EN EL APRENDIZAJE ESCOLAR - INFLUENCE OF ASSERTIVE COMUNICATION STYLES OF TEACHERS IN THE SCHOOL LEARNING

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VIVIANA MONJE MAYORCA

2009-06-01

Full Text Available This research determined the level of influence that assertive style of communication of teachers in the school learning. We used an experimental design; the sample included twelve teachers for the experimental group, and other twelve for the control group of the Empresarial de los Andes School (Department of Huila. The results show that school’s a stage of social life where the educational processes of the teachers have a deep character communicative and the institution have not recognized the importance of communication in processes like the personality, socialization and learning development. Similarly, was established that both, teachers and students, use alternate indirect ways of communication, which does not allow a proper process of personal interaction. It was shown, that with appropriate intervention, the communication channels are optimized, improving the academic performance of students.

Landscape-based discretization for modeling of hydrological processes in the semi-arid Andes Cordillera: a case study in Morales Basin

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Videla Giering, Y. A., III; McPhee, J. P.; Pomeroy, J. W.

2017-12-01

Improved understanding of cryosphere processes in the Subtropical Andes is essencial to secure water supply in Central Chile. An ongoing challenge is to identify the main controls on snow accumulation and ablation at multiple scales. In this study, we use the Cold Regions hydrological model (CRHM) to simulate the evolution of seasonal snow cover in the basin of the Estero Morales between the period 2000-2016. The model was forced with radiation, temperature, humidity, wind and precipitation data obtained from downscaled Era-Interim outputs. The basin was disaggregated spatially through representative hydrological processes and and geomorphological into HRU's. 22% of snow in the basin is subject to reallocation by topographic effects, while net short wave radiation would explain major changes in snowmelt. 80% of summer runoff comes from glacial melting, while temperature and soil properties are key factors controlling infiltration and contribution to the runoff at all times of the year. The model results indicate that 78.2% of precipitation corresponds to snow while 21.8% to rain. The flow rates of snowmelting are the main component in the water balance, accounting for approximately 62.8% of the total rainfall. It is important to point out that during the total period of modeling (2010-2016), it was noted that the 23.08% of the total annual flow corresponds to glacial melting, however for the period 2010 - 2015 this percentage increases to 45.3%, in spite of this were not observed variations in the volume of subsurface and groundwater flow. This suggests first: that systems such as analyzed in this article, have a great importance because they are fragile in terms of response and the ground due to its topographic features (such as slope and conductivity) is not able to store large percentages of resources until the end of the summer season; and second, to understand that mountain systems with presence of glaciers, naturally are regulated compared to sudden changes

"Nervios" and "Modern Childhood": Migration and Shifting Contexts of Child Life in the Ecuadorian Andes.

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Pribilsky, Jason

2001-01-01

Argues that beyond explanations predicated on psychological ideas of separation and attachment, "nervios," a depression-like disorder among children in the southern Ecuadorian Andes, reflects the limits of children's abilities to accept terms of family life increasingly defined through transnational migration and new consumption…

Identificación de áreas de homogeneidad estadística para los caudales de ríos andinos argentinos y su relación con la circulación atmosférica y la temperatura superficial del mar Identification of statistical homogeneous areas for argentinean andean river flows and their relationship with the atmospheric circulation and sea surface temperatures

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Rosa H. Compagnucci

2005-12-01

Full Text Available El presente trabajo se centra en localizar las distintas regiones a lo largo de la Cordillera de los Andes sobre las cuales el comportamiento de los caudales de los ríos involucrados muestran homogeneidades estadísticas, estudiando además su vinculación con las condiciones de Temperatura de la Superficie del Mar y Circulación Atmosférica. Se define un índice lineal de correlación corregido, utilizado como medida de distancia en un Análisis de Componentes Principales. Las primeras dos Componentes permiten identificar dos regiones independientes que explican la mayor variabilidad. Estas regiones abarcan: I desde el río Neuquén hasta el río Senguer y II desde el río Jachal hasta el río Colorado. La región I presenta un régimen de doble máximo de caudal en invierno-primavera, mientras que la región II se caracteriza por un máximo en verano. Esta última estaría íntimamente ligada a los patrones del ciclo El Niño / Oscilación Sur. Las diferencias más relevantes de la circulación asociada a los extremos de caudal en la región I con respecto a la II serían: 1 el corrimiento de los sistemas de circulación hacia mayores latitudes, 2 la mayor relevancia de los sistemas de latitudes medias, 3 la menor importancia de los ubicados sobre el Pasaje de Drake y 4 la presencia en altura de un tren de ondas estacionarias de menor longitud que atraviesa el continente por latitudes subtropicales provenientes del Pacífico central en dirección NO-SE.The purpose of this paper is to locate the different regions in Los Andes mountain range on which the behavior of the flows of the involved rivers shows statistical homogeneities, studying also their entailment with sea surface temperature and atmospheric circulation. A corrected correlation linear index is defined and used as a distance measurement in a Principal Component Analysis. The first two Components identify two independent regions that explain the greater variability. These regions

The subduction erosion and mantle source region contamination model of Andean arc magmatism: Isotopic evidence from igneous rocks of central Chile

International Nuclear Information System (INIS)

Stern, Charles R

2001-01-01

Continental crust may be incorporated in mantle-derived Andean magmas as these magmas rise through the crust (Hildreth and Moorbath, 1988), or alternatively, crust may be tectonically transported into the mantle by subduction of trench sediments and subduction erosion of the continental margin, and then added into the mantle source region of Andean magmas (Stern, 1991). Since the mantle has relatively low Sr, Nd, and Pb concentrations compared to continental crust, differences in the isotopic compositions of magmas erupted in different region of the Andes may be produced by relatively small differences in the amount of subducted crust added to the mantle source region of these magmas. By comparison, significantly larger amounts of crust must be assimilated by mantle-derived magmas to produce isotopic differences of similar magnitude. Therefore, constraining the process by which continental crust is incorporated in Andean magmas has important implications for understanding the chemical cycling that takes place in the Andean subduction-related magma factory. Isotopic data suggest the incorporation of a greater proportion of crust in Andean magmas erupted at the northern portion of the Southern Volcanic Zone of central Chile compared to those erupted in the southern portion of the Southern Volcanic Zone of south central Chile (SSVZ) (Stern et al., 1984; Futa and Stern, 1988; Hildreth and Moorbath, 1988). The NSVZ occurs just south of the current locus of the subduction of the Juan Fernandez Ridge. The southward migration of the locus of subduction of this ridge has resulted in decreasing subduction angle below the NSVZ, the eastward migration of the volcanic front of the Andean arc, and an increase in the crustal thickness below the arc. These factors together have caused changes, since the middle Miocene, in the isotopic composition of Andean igneous rocks of central Chile. The data indicate a close chronologic relation between the southward migrations of the locus

Adaptive institutions? Peasant institutions and natural models facing climatic and economic changes in the Colombian Andes

NARCIS (Netherlands)

Feola, Giuseppe

2017-01-01

In the Colombian Andes, peasants have co-evolved with their environment for centuries, but it is uncertain whether traditional informal institutions and natural models are adapting to current and possibly unprecedented economic and climatic disturbances. This study investigated institutional

A TRAVÉS DE LOS ANDES. ESTRATEGIAS SOCIALES Y REDES DE PODER ENTRE CÓRDOBA Y HUANCAVELICA EN EL SIGLO XVIII

OpenAIRE

Mar\\u00EDa Victoria M\\u00E1rquez

2012-01-01

Se indaga en la participación y los usos de los espacios burocráticos y administrativos por parte de la élite colonial en el siglo XVIII. Para ello se aborda el caso de una familia de grandes tratantes del comercio interregional- los Mendiolaza- cuyos intereses se asentaron en diversos puntos de la región andina. Así se propone una mirada comparativa sobre las estrategias de un mismo entramado social o red de relaciones. El artículo hace foco en dos lugares, Córdoba y Huancavelica, en tanto s...

Caracterización y propue stas de mejora de los sistemas de producción caprina de la costa central de Perú