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Sample records for los andes centrales

  1. Bofedales: high altitude peatlands of the central Andes Bofedales: turberas de alta montaña de los Andes centrales

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    FRANCISCO A SQUEO

    2006-06-01

    Full Text Available There is an exceptional group of alpine peatlands in the world situated in the arid grasslands of the central Andes. The peatlands in northern Chile occur in the most arid part of their range. Members of the Juncaceae are the primary peat-forming plant species. Fresh and mildly saline groundwaters originate from glaciers, snowmelt and rain are the water sources for the northern Chile peatlands. Paleoecological investigations suggest that some peatlands are recent features of the landscape having developed within the last three thousand years or less. These peatlands are unique, extremely fragile water features sensitive to climate changes and human disturbances such as regional mining activity. Much more work is required to develop scientifically based sound management and conservation programs for the rare plants and animals that live in them and to ensure the future livelihoods of the indigenous peoples who depend on themExiste un grupo excepcional de turberas (bofedales de alta montaña en el mundo situados en la estepa árida de los Andes centrales. Los bofedales en el norte de Chile están presentes en la parte más árida de su rango. Las principales especies de plantas responsables de la formación de turba corresponden a miembros de Juncaceae. El agua fresca y medianamente salina de los bofedales proviene de agua subterránea asociada a riachuelos proveniente de glaciares, derretimiento de nieve y lluvia. Investigaciones paleoecológicas sugieren que algunos bofedales son integrantes recientes del paisaje, habiéndose desarrollado durante los últimos tres mil años o menos. Estos bofedales son entidades únicas, extremadamente frágiles por su dependencia del agua, sensibles a los cambios climáticos y vulnerables a la alteración humana tal como la actividad minera en la región. Se requiere mucho más trabajo para desarrollar programas de manejo y conservación, con sólidas bases científicas, de las plantas y animales que viven en

  2. Contenidos de uranio de lavas recientes en el sector sur de los Andes centrales

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    Guerra, N.

    1984-12-01

    Full Text Available We have studied the distribution of U in modern lava -flows of the southern part from the Central Andes (16°-28° S. For a given SiO2, content of the rocks, U abundance increases from west to east in a transects to the Andean Belt, while the depth of the subduction zone increases and the thickness of the continental curst decreases. Besides, U content tends to inerease steadly with the latitude, while the thick of the continental crust and the depth of the seismic zone decreases southward. Thus, on the basis of the available data, we are in a position to suggest that the U behavior in the studied lavas depends on the alkalanity and magmatic history of each volcanic center.

    Se presenta un estudio de distribución de U en lavas modernas del sector sur de los Andes centrales (16°-28° S. Para rocas de contenidos similares en SiO2 la abundancia de U crece de oeste a este en un perfil transversal al cordón andino, mientras que aumenta la profundidad de subducción, y disminuye la potencia de la corteza continental. Además, mientras la potencia de la corteza continental y la profundidad de la zona sísmica de Benioff disminuyen hacia el sur, U tiende a aumentar con la latitud. Así, y basado en los datos disponibles, estamos en posición de sugerir que el comportamiento de U en las rocas estudiadas, depende de la alcalinidad y de la historia magmática de cada centro volcánico.

  3. Cronología, identidad, urbanismo y estado en los Andes Centrales y surcentrales entre los siglos V a X D.C.: algunas reflexiones finales

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    Kaulicke, Peter

    2012-01-01

    Chronology, Identity, Urbanism and State in the Central and South Central Andes between V and X Centuries AD: Some Final ConclusionsThe article doesn´t have an abstract El artículo no presenta resumen

  4. Altitudinal vegetation belts in the high-Andes of central Chile (33°S Pisos altitudinales de vegetación en los Andes de Chile central (33°S

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    Lohengrin A. Cavieres

    2000-06-01

    Full Text Available The limits of alpine vegetation belts have been established mainly based on physiognomic criteria. However, a more objective approach for fixing limits of vegetation belts are methods based on species composition and relative abundance of each species. While these methods are more time consuming, they are more detailed and permit the detection of physical factors affecting the limits of vegetation belts. In this paper we: 1 describe the altitudinal changes of vegetation above timberline, 2 compare vegetation belts defined with physiognomy and two floristic methods (a qualitative one based on altitudinal changes in species composition, and a quantitative one based on changes in dominant species; and 3 detect some environmental factors responsible for the altitudinal distribution of alpine vegetation between 2100 and 3700 masl in the Andes of Santiago, central Chile (33°S. There was a complete agreement between the different methods in delimiting the subalpine belt. However, in the lower alpine belt (the cushion's belt floristic methods subdivided it in 2-3 sub-belts. In the floristic methods, elevations 3500-3700 that formed the higher alpine belt segregated in separate ways because they have no species in common. Physiognomic descriptions lose relevant information about species distribution, especially at higher elevations. Mean annual temperature and nitrogen content of soil are the main environmental factors affecting the altitudinal limits of vegetation belts in the central Chilean AndesLa delimitación de los pisos altitudinales de vegetación andina se ha basado principalmente en criterios fisionómicos. Sin embargo, un criterio más objetivo para la delimitación es usar métodos basados en la composición y abundancia relativa de las especies presentes. Mientras estos métodos requieren de un mayor esfuerzo de muestreo, son más detallados y permiten detectar factores físicos involucrados en la delimitación altitudinal de la vegetaci

  5. Ordenar para controlar. Ordenamiento espacial y control político en las Llanuras del Caribe y en los Andes Centrales Neogranadinos. siglo XVIII

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    Beatriz Patiño Millán

    2002-01-01

    Full Text Available Marta Herrera Ángel. Ordenar para Controlar. Ordenamiento espacial y control político en las Llanuras del Caribe y en los Andes Centrales Neogranadinos. Siglo XVIII. Bogotá: Instituto Colombiano de Antropología e Historia - Academia Colombiana de Historia, 2002, pp. 343. En este libro Marta Herrera estudia la estructuración del ordenamiento espacial y político durante el siglo XVIII de las llanuras del Caribe, nombre con el cual denomina el ámbito espacial correspondiente a las gobernaciones de Cartagena y Santa Marta,  y los Andes Centrales, apelativo que utiliza para referirse a los territorios de la provincia de Santafé y la jurisdicción de la ciudad de Tunja.

  6. 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.; Fuentes, Esteban P.

    2005-01-01

    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 encontrado...

  7. Parasite loads and altitudinal distribution of Liolaemus lizards in the central Chilean Andes Cargas parasitarias y distribución de lagartijas Liolaemus en los Andes de Chile central

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    JOHN H. CAROTHERS

    2001-09-01

    Full Text Available This study compared the distributions of ten species of Liolaemus lizards in the central Chilean Andes to the distributions of four types of parasites: malaria-causing Plasmodium, gut nematodes, ticks, and mites. We wanted to see if parasite numbers might be a factor in determining distributional limits of the lizards. We found that there was no evidence of malarial infestation of the lizards, that ticks were almost absent, that more often than not mite numbers decreased at the distributional limits of the lizards, and that gut nematodes confined to the herbivorous lizards in our sample may well be beneficial rather than detrimental. Rather than parasitism, other biotic interactions (e.g., predation or competition are more likely candidates as factors influencing lizard elevational distributions, as are abiotic characteristics such as microhabitat availabilities and thermal factorsEste estudio compara las distribuciones de diez especies de lagartijas Liolaemus en los Andes de Chile central, con las distribuciones de cuatro tipos de parásitos: Plasmodium causantes de malaria, nemátodos intestinales, garrapatas y ácaros. Quisimos verificar si los números de parásitos pudieran ser un factor determinante de los límites de distribución de las lagartijas. Encontramos que no había evidencia de infestación por malaria en las lagartijas; que las garrapatas estaban casi ausentes; que los números de ácaros más a menudo decrecían que aumentaban en los límites distribucionales de las lagartijas; y que los nemátodos intestinales confinados a las lagartijas herbívoras en nuestra muestra bien podían ser beneficiosos antes que dañinos. Más bien que parasitismo, otras interacciones bióticas (e.g., depredación o competencia son candidatos más probables como factores que influyen las distribuciones altitudinales de las lagartijas, además de características abióticas tales como la disponibilidad de microhábitats y los factores térmicos

  8. 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.

  9. 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

  10. 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.

  11. Variaciones de un glaciar de montaña en los Andes de Chile central en las últimas dos décadas

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    1995-01-01

    Full Text Available VARIATIONS D’UN GLACIER DE MONTAGNE DANS LES ANDES DU CHILI CENTRAL AU COURS DES DEUX DERNIÈRES DÉCENNIES. Les résultats du bilan de masse du glacier Echaurren Norte sont présentés. Il s’agit d’un glacier de montagne de 0,4 km2 situé dans les Andes du Chili central, à 50 km à l’est de Santiago, à une altitude moyenne de 3 750 m. Ce programme de la Direction Générale d’Eaux du Chili a permis de recueillir régulièrement une information sur les bilans de masse pendant 18 ans, entre les années 1975 et 1993. C’est le seul registre de bilan de masse d’un glacier au Chili. L’ablation pendant la période de fonte a été de 252 cm d’eau en moyenne annuelle, avec une accumulation hivernale moyenne de 280 cm d’eau. Le bilan net est positif pour la période, mais on observe une grande variation interannuelle. Le bilan positif du glacier Echaurren Norte contraste avec le recul généralisé des autres glaciers du Chili central. Se presentan resultados del balance de masa del glaciar Echaurren Norte, un glaciar de montaña de 0,4 km2 ubicado a una altitud media de 3 750 m.s.n.m., en los Andes de Chile central, 50 km al este de Santiago. Los datos, recolectados como parte de un programa regular de la Dirección General de Aguas, Chile, cubren un período de 18 años, desde 1975 a 1993 y constituyen el único registro de balance de masa de un glaciar en Chile. La ablación durante el período de deshielo fue de 252 cm eq. en agua anuales en promedio, con una acumulación invernal promedio de 280 cm eq. en agua. El balance neto para el período es positivo, pero existe una gran variación interanual. El balance positivo del glaciar Echaurren Norte contrasta con el retroceso generalizado en otros glaciares de Chile central. VARIATIONS OF A MOUNTAIN GLACIER IN THE CENTRAL CHILEAN ANDES DURING THE LAST TWENTY YEARS. Mass balance results for Echaurren Norte Glacier are presented. This mountain glacier, with an area of 0,4 km2, is located at

  12. Del santuario al caserío: acerca de la neolitización en la Cordillera de los Andes Centrales

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    1988-01-01

    Full Text Available Les faits archéologiques mis en évidence sur le site de Piruru ouvrent des perspectives nouvelles sur la sédentarisation et l'apparition du village dans les Andes centrales. Piruru présente, au Précéramique Final (3000/2500 - 1800/1500 av.JC, une longue période de construction à des fins religieuses avant que n'existent, au Formatif Initial et Moyen (1800/1500 - 800/600 av.JC, des structures à usage domestique. Cette antériorité de l'architecture publique et cérémonielle, observable à l'échelle régionale, permet de proposer l'hypothèse qu'au Précéramique Final, les sanctuaires montagnards jouent un rôle catalyseur, non seulement dans la naissance et le développement de l'architecture, mais aussi dans l'organisation spatiale des communautés en cours de sédentarisation. Durant la longue occupation du Précéramique Final, plus de 1000 ans, les premières phases de la séquence de Piruru montrent l'existence de petits temples, qui sont les plus anciens connus actuellement dans les Andes centrales. Ensuite, la phase plus récente du temple P1 permet de relier Piruru aux autres sanctuaires connus, et de définir la tradition Mito, courant religieux qui se manifeste dans les Andes d'Ancash et de Huánuco, durant la deuxième partie du Précéramique Final. Au Formatif Initial, dans le même temps où la céramique est introduite sur le site, Piruru devient un petit habitat groupé, premier exemple connu à ce jour en montagne. Au cours d'un processus long de plus de 700 ans, les transformations dans l'organisation globale de l'habitat indiquent un degré croissant de sédentarité, et montrent le passage d'un hameau utilisé de façon saisonnière à un village habité de façon permanente, la sédentarité paraissant acquise au début du Formatif Moyen. Los hechos arqueológicos puestos en evidencia en el sitio de Piruru ofrecen nuevas perspectivas sobre la sedentarización y la aparición de la aldea en los Andes centrales

  13. 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

  14. 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.

  15. The Southern Central Andes vertical axis tectonic rotations: relations with the deformation pattern Rotaciones tectónicas según ejes verticales en los Andes Centrales del Sur: relaciones con el patrón de deformación

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    Claudia Prezzi

    2012-05-01

    Full Text Available Along the Central Andes a pattern of vertical axis tectonic rotations has been paleomagnetically identified. Such rotations are counterclockwise north of Arica Deflection (~19°S and clockwise to the south. Different hypothesis and models have been proposed to explain the Central Andean Rotation Pattern (CARP. However, the CARP is a subject of ongoing debate. Recently, the quantity, quality, and geographic distribution of paleomagnetic data have expanded greatly. Such expansion has been accompanied by an increase in the knowledge of the deformation periods in the Andes, allowing a more detailed analysis of the temporal and spatial distribution of the detected rotations. We compiled and analyzed the available Cenozoic paleomagnetic data for the region extending between 19° and 27.5°S. The results suggest the possible existence of different rotational domains with distinct characteristics. We propose that in the Southern Central Andes, a close correlation would exist between the style and the temporal and spatial pattern of deformation and the amount of recorded vertical axis rotations. However, in order to further investigate such relationship, new paleomagnetic studies are necessary, particularly in the Eastern Cordillera domain, in Paleogene rocks cropping out in the Altiplano-Puna and in Neogene rocks of the forearc.En los Andes Centrales se ha identificado un patrón de rotaciones tectónicas según ejes verticales a través de estudios paleomagnéticos. Dichas rotaciones son en sentido antihorario al norte del codo de Arica (~19°S y en sentido horario hacia el sur. Distintos autores han propuesto diferentes hipótesis y modelos para tratar de explicar el Patrón de Rotaciones de los Andes Centrales (PRAC. Sin embargo, el PRAC sigue siendo objeto de debate. Recientemente, la cantidad, calidad y la distribución geográfica de los datos paleomagnéticos ha aumentado de manera notable. Dicho incremento ha sido acompañado por un importante

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

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    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...

  17. 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

  18. 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

  19. El clima de la vertiente del Pacífico de los Andes Centrales y sus implicaciones geomorfológicas El clima de la vertiente del Pacífico de los Andes Centrales y sus implicaciones geomorfológicas

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    Jose Úbeda Palenque

    2008-12-01

    ífico de los Andes Centrales, entre 15°S y 19°S, debido a que los procesos mediante los cuales se desarrolla el modelado del relieve o morfogénesis están controlados por las variables termo-pluviométricas y la fito-estabilización. Además, la geodinámica interna de la región se encuentra igualmente relacionada con las condiciones climáticas, que determinan la cuantía del aporte de sedimentos a la fosa oceánica (Kulm et al. 1977, afectando a la tasa de erosión por subducción en el plano de contacto entre las placas y a la composición de los magazas que se forman bajo el erógeno andino. En esta ponencia se analizan los efectos del clima en la geodinámica externa, en un marco teórico en el que se considera que un sistema morfoclimático es un conjunto integrado por los agentes y procesos morfogenéticos que realizan el modelado del relieve en un territorio, en función de sus características bioclimáticas, y un dominio o piso morfoclimático es el ámbito espacial en el que se desarrolla un determinado sistema morfoclimático.En primer lugar se realiza una presentación del clima en los Andes Centrales, los factores que controlan su configuración media y sus principales características, presentando diagramas elaborados a partir de datos termo-pluviométricos recogidos en una serie de observatorios regularmente distribuidos por la región. En segundo lugar, se diferencias dos dominios climáticos, uno en el altiplano, relacionado con las precipitaciones de componente amazónica, y otro en la rampa que desciende hacia el océano y en la costa del Pacífico, asociado a la situación anticiclónica permanente al O de la cordillera. En tercer lugar, se propone una compartimentación de la fachada occidental de la cordillera en intervalos altitudinales o pisos bioclimáticos, para cuya definición se han empleado como bioindicadores la ausencia de vegetación (por causas térmicas o hídricas o su presencia con un cambio altitudinal de facies (supraforestal

  20. 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

  1. 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

  2. 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...

  3. Mountain building in the central Andes

    Science.gov (United States)

    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

  4. AREAS OF ENDEMISM IN THE SOUTHERN CENTRAL ANDES

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    Lone Aagesen

    2012-01-01

    Full Text Available Este trabajo analiza la distribución de especies de plantas vasculares endémicas de la porción sur de los Andes centrales (sudoeste de Bolivia y noroeste de Argentina. En el análisis se incluyeron 540 especies endémicas de la región estudiada (aproximadamente 720.600 km2. La mayoría de las especies endémicas se halla en ambientes semiáridos, entre 1500-3500 m s.m., encontrándose principalmente en valles, laderas y mesetas del topográficamente complejo sur de los Andes centrales. Las áreas de endemismos aquí halladas se presentan consecuentemente en ambientes áridos y no en ambientes húmedos subtropicales de las Yungas tucumano-bolivianas, a pesar de que en esta última región la diversidad de plantas vasculares es mayor. Se identificaron un total de 17 patrones de distribución bien definidos, y parcialmente solapados. El patrón de distribución más amplio define un área general de endemismos para los Andes centrales. Esta área se extiende a lo largo de casi toda la región y está delimitada por especies que se distribuyen en ambientes desérticos a sub-húmedos en laderas, valles o regiones altoandinas. Casi todas las restantes áreas de endemismo se encuentran anidadas dentro del patrón de distribución amplio antes citado, superponiéndose en el sentido norte-sur a lo largo de pendientes y valles de los Andes y de las Sierras Pampeanas. A pesar del sesgo observado en la distribución hacia ambientes áridos, aproximadamente la mitad de las especies endémicas están restringidas a unas pocas áreas de alto endemismo, las que se encuentran en yuxtaposición con las zonas más lluviosas de la región. Estas áreas de alto endemismo incluyen los rangos de hábitat más amplios de la región en términos de altitud y precipitación, siendo las especies endémicas igualmente variables en sus requerimientos de humedad y elevación. Las unidades fitogeográficas previamente definidas por diversos autores no fueron encontradas

  5. 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

    Directory of Open Access Journals (Sweden)

    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.

  6. 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

  7. 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

  8. Memoria de los Andes, memoria de la naturaleza

    OpenAIRE

    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 ...

  9. Linchamientos y conflicto político en Los Andes Lynchings and Political conflict in The Andes

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    Carlos M. Vilas

    2007-06-01

    Full Text Available En 2004, los alcaldes de dos municipalidades de la región aimara de los Andes fueron linchados en la aparente culminación de agudos conflictos políticos internos y entre las respectivas comunidades y el Estado central. En este artículo se discuten ambos casos con el fin de ilustrar las transformaciones experimentadas en años recientes en la organización y la dinámica interna de las comunidades andinas, y de la articulación conflictiva de la política local en los procesos e instituciones de más amplio alcance. Precariedad social e incapacidad o renuencia del Estado para responder con eficacia a demandas básicas de determinados grupos de población configuran enmarcamientos socioeconómicos e institucionales de los linchamientos. En contraste con enfoques que enfatizan en factores culturales tradicionales o en un supuesto nacionalismo indígena, en el artículo se destaca la gravitación de fenómenos y procesos político- institucionales recientes en la transformación cultural y política de las comunidades, en el modo en que éstas procesan sus conflictos internos y con el Estado central.In 2004, two municipalitys mayors form the aimara Andes of Peru and Bolivia were subjected to mass lynchings as a result of the apparent culmination of violent political confrontations. This paper deals with these events as dramatic illustrations of the transformations the Andean communities experienced during recent decades in their internal dynamics, as well as in the articulation of local politics to processes and institutions beyond the communal limits. Structural precariousness combined with the state's inability or reluctance to come to terms with social or political demands from relevant segments of the people in the communities set the socioeconomic and institutional stage for lynchings. In contrast with approaches relating these events to an alleged indigenous cultural identity, the analysis points to the impact of the communities' political

  10. Paleohidrología de los últimos 25000 años en los Andes bolivianos

    Directory of Open Access Journals (Sweden)

    1995-01-01

    Full Text Available PALÉOHYDROLOGIE DES DERNIÈRES 25 000 ANNÉES DANS LES ANDES BOLIVIENNES. Nous présentons une reconstruction climatique de haute résolution de l’Altiplano bolivien (Andes Centrales basée sur des données géomorphologiques, sédimentologiques, palynologiques et provenant de l’analyse des faunes d’ostracodes. Nous avons déterminé (1, de manière semi-quantitative, la température ainsi que (2 de façon quantitative, les variations des niveaux lacustres depuis la fin du Pléistocène (25 000 ans BP. Les principaux résultats obtenus sont les suivants: de 25 000 à 18 000 ans BP, les températures atmosphériques sont basses ainsi que les niveaux des lacs entre 18 000 et 15 000/14 000 ans BP, la présence d’une lacune de sédimentation est indicatrice d’une phase climatique sèche pendant le Tardi-Glaciaire (15 000/14 000 - 10 500, les lacs (phase Tauca et les glaciers se sont étendus de 10 500 à 8000 ans BP, les lacs et les glaciers reculent très rapidement pendant que la température globale moyenne augmente à l’Holocène moyen (8 000-3 900 ans BP, le climat régional est globalement de type sec autour de 3900 ans BP, le niveau du lac Titicaca monte fortement des conditions relativement humides s’installent alors et se maintiennent par la suite pendant le Petit âge de la Glace (16ème-19ème siècles, des conditions froides et humides prévalent. En base a datos geomorfológicos, sedimentológicos, palinológicos y el análisis de fauna de ostrácodos, se ha determinado (1, de manera semicuantitativa, la temperatura así como (2 los cambios cuantificados de las variaciones de los niveles lacustres desde el final del Pleistoceno (25 000 años BP. Los principales resultados obtenidos son los siguientes: de 25 000 a 18 000 años BP, las temperaturas atmosféricas son bajas así como los niveles de los lagos entre 18 000 y 15 000/14 000 años BP, una fase climática seca es definida por la presencia de una laguna de sedimentaci

  11. Identificación, caracterización y dinámica de las geoformas glaciales y periglaciales en la Cordillera de los Andes a través de sensores remotos

    OpenAIRE

    Falaschi, Daniel

    2015-01-01

    El presente trabajo de Tesis Doctoral tuvo el objetivo de estudiar los glaciares y glaciares de escombros en tres regiones montañosas a lo largo de la Cordillera de los Andes Argentina: Monte San Lorenzo (Provincia de Santa Cruz), Volcán Domuyo (Provincia de Neuquén), y Nevados de Cachi (Provincia de Salta). Cada uno de estos sitios presenta características climáticas propias, representativas de tres porciones particulares de los Andes: Andes Patagónicos Meridionales, Andes Centrales Meridion...

  12. 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

  13. Tectonic control of erosion in the southern Central Andes

    Science.gov (United States)

    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.

  14. Subvolcanic contact metasomatism at El Laco Volcanic Complex, Central Andes Metasomatismo de contacto subvolcánico en el Complejo Volcánico El Laco, Andes centrales

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    José A Naranjo

    2010-01-01

    Full Text Available Studies of drill cores from the Pasos Blancos area at El Laco in the central Andes, northern Chile, give evidence of an intense and extensive subvolcanic contact-metasomatic process. This process resulted from shallow-level emplacement of very volatile-rich iron-oxide magma, with discharge of volatiles that resulted in extensive fracturing of overlying volcanic rocks. The brecciated rocks were altered (mainly extensive scapolitization and formation of pyroxene by hot magmatic fluids emitted from the cooling intrusion , and accompanied by magnetite deposition. With time and decreasing temperature, the metasomatic fluids evolved to fluids of hydrothermal character, and a final recent geothermal event took place that deposited superficial gypsum over a large part of the El Laco Volcanic Complex.Estudios realizados en testigos de sondajes en el area de Pasos Blancos en El Laco, en los Andes Centrales del norte de Chile, dan evidencias de un intenso y extenso proceso subvolcánico de metasomatismo de contacto. Este proceso es el resultado de un emplazamiento a poca profundidad de un magma de óxido de fierro muy rico en volátiles y cuya descarga de gases produjo un intenso fracturamiento de las rocas sobrepuestas. Las rocas brechizadas fueron alteradas (principalmente una extensa escapolitización y formación de piroxeno, junto con la depositación de magnetita, por los fluidos magmáticos calientes emitidos por la intrusión durante su enfriamiento. Los fluidos metasomáticos evolucionaron en el tiempo y con la disminución de temperatura, a fluidos de carácter hidrotermal y finalmente tuvo lugar un evento geotérmico reciente, el cual depositó yeso superficial en gran parte del Complejo Volcánico El Laco.

  15. 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.

  16. 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.

  17. Primer registro del frutero pechinegro Pipreola lubomirskii (Aves, Cotingidae en la vertiente occidental de los Andes

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    Letty Salinas

    2013-06-01

    Full Text Available El frutero pechinegro, Pipreola lubomirskii, es un cotíngido registrado como raro y de distribución local en los Andes del Norte. Antes del presente registro sólo había sido reportado para la vertiente oriental del Perú y Ecuador, así como los Andes del sur de Colombia. El presente registro amplia su distribución a los bosques montañosos de la vertiente occidental de los Andes peruanos, habiéndose encontrado en los bosques nublados del valle del río Zaña, en el departamento de Cajamarca (6º50’-6º52’ latitud S, 79º10’-79º07’ longitud O.

  18. Oroclinal Bending and Mountain Uplift in the Central Andes

    Science.gov (United States)

    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

  19. 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.

  20. Steady-state exhumation pattern in the central Andes SE Peru

    NARCIS (Netherlands)

    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

  1. 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.

  2. 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.

  3. 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

  4. Palabras y silencios: la retórica del poder en los Andes

    Directory of Open Access Journals (Sweden)

    1997-01-01

    Full Text Available PAROLES ET SILENCES : LA RETHORIQUE DU POUVOIR DANS LES ANDES. La parole condense différents arguments et formes de pouvoir dans les sociétés andines. Le domaine social et le cadre cérémoniel appartiennent à ceux qui articulent bien les mots. La différenciation entre la valeur octroyée à la parole et celle correspondant aux silences implique diverses modalités de prestige de reconnaissance sociale et de pouvoir rituel dans les Andes. Les personnes, les vivants et les savants exercent une maîtrise subtile de la parole face aux étrangers, aux défunts et aux sots, qui demeurent socialement “muets”, silencieux. La palabra condensa diferentes argumentos y formas de poder en las sociedades andinas. El dominio social y el ámbito ceremonial pertenecen a los buenos articuladores de palabras. La diferenciación entre el valor otorgado a la palabra y el que corresponde a los silencios implica diferentes modalidades de prestigio, reconocimiento social y poder ritual en los Andes. Las personas, los vivos y los sabios ejercen un dominio exquisito de la palabra frente a los extraños, los difuntos y los “necios” que permanecen socialmente “mudos”, callados. WORDS AND SILENCES: THE RHETORIC OF POWER IN THE ANDES. Words have different meanings and means to exercise power in Andean societies. Social power and ceremonial environments belong people who are fluent in language. The difference between the value ascribed to the spoken word and that ascribed to silence implies several kinds of prestige, social recognition and ritual power in the Andes. “Ordinary”, alive and wise people exert an exquisite authority with words as compared with strange, dead and “stupid people” who remain socially 'dumb', silent.

  5. 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.

  6. 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

  7. La Cordillera de los Andes: presentación de los problemas geomorfológicos

    Directory of Open Access Journals (Sweden)

    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

  8. 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.

  9. De Los ríos profundos a Lituma en los andes: La respuesta de Mario Vargas Llosa a José María Arguedas

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    Marie-Madeleine Gladieu

    2011-05-01

    Full Text Available La novela de Mario Vargas Llosa Lituma en los Andes1 poco tiene que ver, aparentemente, con el mundo narrativo de José María Arguedas: las nuevas aventuras de un personaje ficticio bien conocido de los lectores, presente en varias obras anteriores de aquel autor, en nada se asemejan a las del niño Ernesto ni a las de otro protagonista arguediano. Los Andes sirven de decorado para los dos relatos, pero entre la naturaleza y los pueblos que se suceden en Los ríos profundos2en toda su diversidad, y los paisajes hoscos y siempre peligrosos por los que cruza Lituma, apenas reconoce el lector aquella parte del sur peruano. Algunos detalles, sin embargo, al examinar bien el texto y el contexto de Lituma en los Andes, llaman la atención.

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. Las sociedades anónimas cruzan los Andes: los inversores chilenos en Neuquén al comenzar el siglo XX

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    Graciela Blanco

    2012-08-01

    Full Text Available El territorio de Neuquén, en el norte de la Patagonia, atrajo la mirada de diversos inversores privados a partir del avance militar que realizó el Estado nacional sobre los grupos indígenas y de la conquista de las tierras del sur argentino; tierras que fueron ofrecidas a particulares en propiedad o arrendamiento en condiciones muy beneficiosas. Este trabajo analiza la conformación en Chile, en los primeros años del siglo XX, de sociedades anónimas que explicitaban como objetivo central la intención de comprar tierras a ambos lados de la Cordillera de los Andes para la explotación agroganadera y la comercialización, y estudia específicamente el origen, itinerario y organización productiva de una de esas sociedades en Neuquén.Neuquen territory, in the north of the Patagonia, attracted the look of diverse investors after from the military advance that realized the national State on the indigenous groups and of the conquest of the lands of the Argentine's south, lands that were offered to individuals in property or lease in very beneficial conditions. This work analyzes the conformation in Chile, in the first years of the 20th century, of joint-stock companies that stated explicitly as central aim the intention of buying lands on both sides of the Mountain chain of the Andes for the agricultural and livestock exploitation and the commercialization, and there studies specifically the origin, itinerary and productive organization of one of these companies in Neuquen.

  15. 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

  16. 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.

  17. 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.

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

    OpenAIRE

    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...

  19. 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...

  20. 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 ...

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

    Directory of Open Access Journals (Sweden)

    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

  2. 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

  3. 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

    Directory of Open Access Journals (Sweden)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

  5. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

  13. 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

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

    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...

  15. 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

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. Secuencias y consecuencias de algunos procesos de neolitización en los Andes

    OpenAIRE

    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...

  1. 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.

  2. 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

  3. 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.

  4. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  6. 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

  7. 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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  12. 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

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

    Directory of Open Access Journals (Sweden)

    Aracely Burgos

    2011-10-01

    Full Text Available

    La Región Andina (R.A es uno de los sistemas montañosos más grandes del mundo; atraviesa los países de Chile, Argentina, Bolivia, Perú, Ecuador, Colombia y Venezuela. Este trabajo describe, hace un acercamiento y propone estrategias en tres aspectos que pueden catalogar la “riqueza” y la “pobreza”de estos países: 1. biodiversidad, 2. producción agropecuaria y 3. cultura alimentaria (expresada como seguridad alimentaria en habitantes sobre los 2000 msnm cuyas características de vida son únicas.La información se obtuvo a partir de revisión debases de datos nacionales e internacionales y enrevistas especializadas en cada área y en cada país.La tendencia fue información generalizada para habitantes de la R.A. en cada país o para Latinoamérica; aunque también se encontraron estudios específicos para habitantes sobre los 2000m. La biodiversidad de esta región, expresadaen número de especies y áreas de bosques, es catalogada como mega y a su vez de prioridad enconservación. La producción agropecuaria, sector de un alto impacto económico, ocupa importantes áreas que son aprovechadas con pocos cultivos; requiere uso eficiente de factores productivos, desarrollo y/o aplicación de innovación tecnológica y ampliación dela capacidad para enfrentar diversos riesgos. Encuanto a cultura alimentaria en la mayoría de los países resulta prioritario incrementar el nivel de salud, especialmente en niños y habitantes rurales. Se podría sintetizar que la R.A. es una de las más ricas y a su vez más pobre, a nivel mundial. Pensarlaen un presente y futuro digno requiere de planteamientos estratégicos contundentes que con lleven a1. superar la inercia mental de la realidad actual de pobreza, 2. investigar, 3. tecnificar, 4. educar y 5.hacer inversión económica. La cooperación internacional entre los países será un elemento decisivo.
    The Andean Region

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

    Directory of Open Access Journals (Sweden)

    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.

  15. 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

    Directory of Open Access Journals (Sweden)

    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

  16. 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

  17. 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

  18. 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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  3. 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.

  4. 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)

  5. 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

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. 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.

  9. 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.

  10. 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...

  11. 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

  12. 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.

  13. Andes 1997 Gravity Data

    Data.gov (United States)

    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...

  14. 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

  15. 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

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  19. 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

  20. 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

  1. 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

  2. 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

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

    Directory of Open Access Journals (Sweden)

    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

  4. 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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Carbunco: una investigación clínica en los andes peruanos

    OpenAIRE

    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...

  9. 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 ...

  10. 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.

  11. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    OpenAIRE

    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...

  14. 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...

  15. 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.

  16. Innovación en métodos computacionales en la Universidad los Andes

    Directory of Open Access Journals (Sweden)

    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.

  17. 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...

  18. 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

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

    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.

  20. Carbunco: una investigación clínica en los andes peruanos

    Directory of Open Access Journals (Sweden)

    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.

  1. 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

  2. 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...

  3. La chola en el imaginario de la ciudad: decolonialidad y resistencia en Los Andes bolivianos

    Directory of Open Access Journals (Sweden)

    Cleverth Carlos Cárdenas Plaza

    2018-01-01

    Full Text Available El texto expone cómo la chola paceña, por medio de la fiesta popular del Gran Poder, logró revertir los estereotipos negativos que se urdieron acerca de ella. Especialmente, desde principios del siglo XX, cuando se desarrolló todo un discurso destinado a rezagar a su grupo social. Larson (2001, lo llamo el discurso del antimestizaje. Para revertir tales estereotipos, se usó el prestigio de la fraternidad y se mostró su potencial económico, mediante ello se ha reivindicado su lugar en la sociedad. Pero, sobre todo, impuso su vestimenta, su marcador étnico más visible, ante una sociedad que discrimina y racializa.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

  7. 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

    Directory of Open Access Journals (Sweden)

    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.

  8. 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...

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

    Directory of Open Access Journals (Sweden)

    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.

  10. 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

    Directory of Open Access Journals (Sweden)

    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

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

    OpenAIRE

    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...

  12. Cloud forest restoration for erosion control in a Kichwa community of the Ecuadorian central Andes Mountains

    Science.gov (United States)

    Backus, L.; Giordanengo, J.; Sacatoro, I.

    2013-12-01

    The Denver Professional Chapter of Engineers Without Borders (EWB) has begun conducting erosion control projects in the Kichwa communities of Malingua Pamba in the Andes Mountains south of Quito, Ecuador. In many high elevation areas in this region, erosion of volcanic soils on steep hillsides (i.e., food crops. Following a 2011 investigation of over 75 erosion sites, the multidisciplinary Erosion Control team traveled to Malingua Pamba in October 2012 to conduct final design and project implementation at 5 sites. In partnership with the local communities, we installed woody cloud forest species, grass (sig-sig) contour hedges, erosion matting, and rock structures (toe walls, plunge pools, bank armoring, cross vanes, contour infiltration ditches, etc.) to reduce incision rates and risk of slump failures, facilitate aggradation, and hasten revegetation. In keeping with the EWB goal of project sustainability, we used primarily locally available resources. High school students of the community grew 5000 native trees and some naturalized shrubs in a nursery started by the school principal, hand weavers produced jute erosion mats, and rocks were provided by a nearby quarry. Where possible, local rock was harvested from landslide areas and other local erosion features. Based on follow up reports and photographs from the community and EWB travelers, the approach of using locally available materials installed by the community is successful; plants are growing well and erosion control structures have remained in place throughout the November to April rainy season. The community has continued planting native vegetation at several additional erosion sites. Formal monitoring will be conducted in October 2013, followed by analysis of data to determine if induced meandering and other low-maintenance erosion control techniques are working as planned. For comparison of techniques, we will consider installing check dams in comparable gullies. The October 2013 project will also

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

    Science.gov (United States)

    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.

  14. 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.

  15. 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.

  16. 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

    Directory of Open Access Journals (Sweden)

    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

  17. llustrated review of the leaf-mining Nepticulidae of the central Andes (Peru and Bolivia)

    DEFF Research Database (Denmark)

    Stonis, Jonas R.; Diškus, Arunas; Remeikis, Andrius

    2017-01-01

    We review forty-five species of Nepticulidae (Lepidoptera) based on an analysis of samples collected in the central Andean region of Peru and Bolivia. Thirteen of these species are new to science, and are named and described here: Stigmella paracosma Remeikis & Stonis, sp. nov., S. expressa...

  18. 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.

  19. A NEW SPECIES OF CHLEROGAS FROM THE ANDES OF CENTRAL COLOMBIA (HYMENOPTERA: HALICTIDAE

    Directory of Open Access Journals (Sweden)

    Engel M

    2009-12-01

    Full Text Available ABSTRACTA new species of the long-headed bee genus Chlerogas Vachal (Halictinae:Augochlorini is described and fi gured from a male captured at high elevation in centralColombia. Chlerogas tatamaensis Engel & Gonzalez, new species, is distinguishedfrom its congeners on the basis of integumental coloration and sculpturing as wellas features of the male terminalia. A revised key to the species of Chlerogas isprovided.

  20. 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

    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

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

    Directory of Open Access Journals (Sweden)

    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

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

    Directory of Open Access Journals (Sweden)

    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

  3. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Sustainable extraction tripeperro (Philodendron longirrhizum M. Mora and Croat, Araceae) in the central Andes of Colombia

    International Nuclear Information System (INIS)

    Garcia Nestor; Galeano Gloria

    2009-01-01

    The tripeperro (Philodendron longirrhizum) is a widely distributed hemiepiphyte along the Andean region of Colombia. The aerial roots of this species have been employed as a source of fiber for the production of baskets and other handicrafts in the Eje Cafetero region (Cordillera Central). This activity is concentrated in the town of Filandia, in the Quindio state, where a decrease in the availability of appropriate roots for craftsmanship has been detected over the last years. In order to propose sustainable harvest alternatives, we evaluated the natural stock and product demand of tripeperro. Root production and life cycle, distribution of the harvested areas, harvest time and costs, and product demand were studied. It was found that tripeperro natural stock can only supply the demand for improve the economic benefits for artisans.

  6. 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 ...

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Along and Across Arc Variation of the Central Andes by Single Crystal Trace Element Analaysis

    Science.gov (United States)

    Michelfelder, G.; Sundell, T.; Wilder, A.; Salings, E. E.

    2017-12-01

    Along arc and across arc geochemical variations at continental volcanic arcs are influenced by a number of factors including the composition and thickness of the continental crust, mantle heterogeneity, and fluids from the subducted slab. Whole rock geochemical trends along and across the arc front of the Central Volcanic Zone (CVZ) have been suggested to be primarily influenced by the composition and thickness of the crust. In the CVZ, Pb isotopic domains relate volcanic rock compositions to the crustal basement and systematically varies with crustal age. It has been shown repeatedly that incompatible trace element trends and trace element ratios can be used to infer systematic geochemical changes. However, there is no rule linking magmatic process or chemical heterogeneity/ homogeneity as a result of large crustal magma storage reservoirs such as MASH zones to the observed variation. Here we present a combination of whole rock major- and trace element data, isotopic data and in situ single crystal data from plagioclase, pyroxene and olivine for six stratovolcanoes along the arc front and in the back arc of the CVZ. We compare geochemical trends at the whole and single crystal scale. These volcanoes include lava flows and domes from Cerro Uturuncu in the back-arc, Aucanquilcha, Ollagüe, San Pedro-San Pablo, Lascar, and Lazufre from the arc front. On an arc-wide scale, whole rock samples of silicic lavas from these six composite volcanoes display systematically higher K2O, LILE, REE and HFSE contents and 87Sr/86Sr ratios with increasing distance from the arc-front. In contrast, the lavas have systematically lower Na2O, Sr, and Ba contents; LILE/HFSE ratios; 143Nd/144Nd ratios; and more negative Eu anomalies. Silicic magmas along the arc-front reflecting melting of young, mafic composition source rocks with the continental crust becoming increasingly older and more felsic toward the east. These trends are paralleled in the trace element compositions of plagioclase

  9. 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?

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

    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

  11. 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

  12. Un réseau d'observation des glaciers dans les Andes tropicales

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

  14. 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.

  15. 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.

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

    Science.gov (United States)

    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

  17. 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

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    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

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

    Directory of Open Access Journals (Sweden)

    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

  1. Boron isotopic composition of tertiary borate deposits in the Puna Plateau of the Central Andes, NW Argentina

    International Nuclear Information System (INIS)

    Kasemann, Simone; Franz, Gerhard; Viramonte, Jose G.; Alonso, Ricardo N.

    1998-01-01

    Full text: The most important borate deposits in South America are concentrated in the Central Andes. The Neogene deposits are located in the Puna Plateau of N W Argentina. These continental deposits are stratiform in the tectonically deformed Tertiary rocks. The largest borate accumulations Tincalayu, Sijes and Loma Blanca are part of the Late Miocene Sijes Formation, composed by different evaporitic and clastic units. In the main borate units of each location different phases of borates dominate. In Tincalayu the mayor mineral is borax with minor amounts of kernite and other rare borate minerals (ameginite, rivadavite, etc.). The principal minerals in Loma Blanca are borax with minor ulexite and inyoite. In the two main units of Sijes hydroboracite and colemanite are the major minerals; inyoite and ulexite appear subordinately. The deposition of the borates is due to a strong evaporation in playa lakes, which were fed by boron bearing thermal fluids (Alonso and Viramonte 1990). From Loma Blanca we determined δ 11 B values of ulexite (- 6.3 %0), inyoite (-12.7 %0) and terrugite (-16.2 %0); and from Tincalayu the δ 11 B values of borax (-10.5 %0), tincal (-12.2 %0) kernite (-11.7 %0) and inderite (-15.4 %0). The borates of Sijes are hydroboracite (-16.8 %0 to -17.2 %0), ulexite (-22.4 %0) and inyoite (-28.5 %0 to -29.6 %0). In order to get information about the δ 11 B values and pH of a boron solution we analysed the thermal spring of Antuco. It has a δ 11 B of -12.5%0 at a pH of 7.9. The presently forming ulexite deposit has a δ 11 B of -22.4%0. Borates within one depositional unit show a decreasing δ 11 B value sequence from the Na-Borates to the Ca-Borates related to the boron coordination of the minerals (Oi et al. 1989). The difference in the δ 11 B values excludes the precipitation in equilibrium from solutions with constant pH. According to results from previous work on Neogene borates (Turkey, USA) we interpret the borate succession due to

  2. 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.

  3. 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.

  4. 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 ...

  5. COLUMNEA RANGELII (GESNERIACEAE, A NEW SPECIES FROM THE SERRANÍA DE LOS PARAGUAS IN THE COLOMBIAN ANDES

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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%

  16. 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

  17. Importancia de la heterogeneidad de hábitats para la biodiversidad de hormigas en los Andes de Colombia

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    Mónica Ramírez Ramírez

    2009-04-01

    Full Text Available Entre marzo y octubre de 2002 se compararon los ensamblajes de hormigas que forrajean en el suelo en un sistema no manejado (reserva natural El Ciprés y en algunas fincas vecinas. En dos transectos de 100 m se instalaron estaciones de muestreo cada 10 m con trampa de caída (pitfall y cebo de atún epígeo durante 880 h y 92 días respectivamente. En 1471 eventos de captura se determinaron 68 especies distribuidas en 26 géneros y 8 subfamilias. En el sistema silvopastoril- guayaba y en monocultivo de granadilla (Passiflora ligularis dominaron las especies de hormigas mientras que la distribución fue más equitativa en los usos del terreno con estructura vegetal más compleja (bosque, café, sucesión temprana y banco de forrajes. El sistema silvopastoril-guayaba fue el más rico en especies (31 seguido por café (30 y por el bosque y la sucesión temprana (29. El flujo de especies fue alto en bosque, café y sucesión temprana, indicando que la calidad de la matriz es factor importante para el mantenimiento de la biodiversidad.

  18. 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.

  19. Complicaciones mecánicas de los accesos venosos centrales

    OpenAIRE

    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...

  20. DE LAS ROCALLOSAS A LOS ANDES: EL EXPERIMENTO DE ESCUELAS CHARTER EN EL CONTEXTO POLÍTICO ARGENTINO

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    Mauro Carlos Moschetti

    2016-03-01

    Full Text Available RESUMEN: En 1999, se aprobó en la Provincia de San Luis (Argentina la creación de las denominadas 'Escuelas Experimentales Autogestionadas', inspiradas en el modelo charter norteamericano aunque con importantes diferencias. Este artículo describe la experiencia y explora las circunstancias por las que el proyecto fue desarticulado y abandonado prematuramente. El estudio incluyó un profundo análisis documental y entrevistas con referentes del proyecto, ex-funcionarios del Ministerio de Educación e integrantes de las asociaciones adjudicatarias. Se encontraron profundas incompatibilidades entre los principios rectores del proyecto - democratización, cooperativismo, autonomía y pluralidad -, las prácticas del sistema político provincial, y las estructuras y lógicas de poder tradicionales organizadas a nivel nacional.

  1. Importancia de la heterogeneidad de hábitats para la biodiversidad de hormigas en los Andes de Colombia

    Directory of Open Access Journals (Sweden)

    Armbrecht Inge

    2009-06-01

    Full Text Available Entre marzo y octubre de 2002 se compararon los ensamblajes de hormigas que forrajean en el suelo en un sistema no manejado (reserva natural El Ciprés y en algunas fincas vecinas. En dos transectos de 100 m se instalaron estaciones de muestreo cada 10 m con trampa de caída (pitfall y cebo de atún epígeo durante 880 h y 92 días respectivamente. En 1471 eventos de captura se determinaron 68 especies distribuidas en 26 géneros y 8 subfamilias. En el sistema silvopastoril- guayaba y en monocultivo de granadilla (Passiflora ligularis dominaron las especies de hormigas mientras que la distribución fue más equitativa en los usos del terreno con estructura vegetal más compleja (bosque, café, sucesión temprana y banco de forrajes. El sistema silvopastoril-guayaba fue el más rico en especies (31 seguido por café (30 y por el bosque y la sucesión temprana (29. El flujo de especies fue alto en bosque, café y sucesión temprana, indicando que la calidad de la matriz es factor importante para el mantenimiento de la biodiversidad.

  2. 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

    Directory of Open Access Journals (Sweden)

    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

  3. 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.

    Science.gov (United States)

    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.

  4. 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.

  5. 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.

  6. 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.

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

    Science.gov (United States)

    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.

  8. ASTER Andes

    Science.gov (United States)

    2000-01-01

    In this image of the Andes along the Chile-Bolivia border, the visible and infrared data have been computer enhanced to exaggerate the color differences of the different materials. The scene is dominated by the Pampa Luxsar lava complex, occupying the upper right two-thirds of the scene. Lava flows are distributed around remnants of large dissected cones, the largest of which is Cerro Luxsar. On the middle left edge of the image are the Olca and Parumastrato volcanoes, which appear in blue due to a lack of vegetation (colored red in this composite). This image covers an area 60 kilometers (37 miles) wide and 60 kilometers (37 miles) long in three bands of the reflected visible and infrared wavelength region. It was acquired on April 7, 2000.The image is located at 21 degrees south latitude, 68.3 degrees west longitude. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping and monitoring dynamic conditions and temporal change. Examples of applications include monitoring glacial advances and retreats

  9. 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

  10. Evidences of Episodic Crustal Magmatic Diapir and Shallow Volcanic Activity at Uturuncu, Central Andes, from Geodetic Observations between 2014 - 2017

    Science.gov (United States)

    Lau, H. N.; Tymofyeyeva, E.; Fialko, Y. A.

    2017-12-01

    Previous space geodetic studies using ERS-1/2 and Envisat Interferometric Synthetic Aperture Radar (InSAR) data revealed a broad uplift of 10 mm/yr within the Altiplano-Puna Volcanic Complex (APVC), centered at the Uturuncu volcano, surrounded by a ring of subsidence at a rate of a few millimeters per year. This pattern was attributed to formation of a diapir in the middle of the Altiplano-Puna Magma Body (APMB), at depth of 15-19 km. We use new data from the Sentinel-1 InSAR mission, collected between 2014-2017, to produce high-resolution maps of surface displacements in the satellite's line of sight (LOS) from 4 satellite tracks. We estimated random propagation effects (e.g. due to atmospheric turbulence) using a common-point stacking method by Tymofyeyeva and Fialko [2015] and estimated temporally-correlated propagation effects (e.g. due to seasonal variations in atmospheric moisture) using a regression of the residual phase against topography. The estimated atmospheric artifacts were removed from the interferograms prior to computing the time series of the LOS displacements. The data indicate that the uplift above the APMB has considerably slowed down compared to the 1992-2010 epoch. The observed variations in the uplift rate suggest that the "ballooning" of the mid-crustal diapir is episodic on time scales of year to decades, possibly due to variations in melt supply from the partially molten APMB to the incipient diapir. We also find a previously undiscovered localized uplift 11 km south of Uturuncu's peak with maximum LOS velocities of 10 - 15 mm/yr. Joint inversions of data from different satellite tracks for a point source of inflation in an elastic half space constrain the source depth to be at 2 km, suggestive of a shallow magma chamber or a hydrothermal system.

  11. New stratigraphic, chronologic, and magnetic fabric constraints for Neogene and Quaternary ignimbrites in the Central Andes (South Peru)

    Science.gov (United States)

    De La Rupelle, A.; Thouret, J. C.; Cubukcu, H. E.; Jicha, B.; Bréard, E.; Gerbe, M.-C.; Le Pennec, J.-L.; Diot, H.; Boivin, P.

    2012-04-01

    Central Andean deformation history in southern Peru is recorded in Neogene volcanic units of Ocoña and Cotahuasi canyons that cut across the western Cordillera. Acceleration (100 km3) Nazca (c.24.6 Ma), Alpabamba (19.4-18.0 Ma), and Huaylillas (14.25-12.7 Ma) ignimbrite sheets preceded the canyon incision, whereas sheets of smaller volume (Peru, stratigraphy, chronology, AMS, fabric, Neogene, Quaternary.

  12. Cenozoic foreland basins of Central Andes: a preliminary provenance U-Pb zircon analysis of sedimentary sequences of Calchaqui Valley

    International Nuclear Information System (INIS)

    Oliveira, Alisson Lopes; Hauser, Natalia; Pimentel, Marcio Martins; Matteini, Massimo; Coira, Beatriz; Alonso, Ricardo; Barrientos, Andrea

    2015-01-01

    The Eocene of northwestern Argentina records complex basin and structural evolution, including continental sedimentation of the post-rift Salta Basin and the beginning of the Andean uplift and foreland system evolution. This illuminates a significant period of evolutionary history of this and surrounding basins in northwestern Argentina. U-Pb zircon analyses by LA-ICP-MS for three formations representing post-rift to foreland stages allowed interpretation about provenance terrains. The Lumbrera Formation, representing the post-rift stage, shows bimodal sources with a main zircon population around 462 Ma, and a second population around 1023 Ma. The Los Colorados and Angastaco Formations representing the sedimentation in a foreland basin, show a unimodal source around 490 Ma, and 517 Ma respectively. Zircons younger than 50 Ma were not identified during this study. (author)

  13. Cenozoic foreland basins of Central Andes: a preliminary provenance U-Pb zircon analysis of sedimentary sequences of Calchaqui Valley

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Alisson Lopes; Hauser, Natalia; Pimentel, Marcio Martins; Matteini, Massimo, E-mail: alisson_oliveira@hotmail.com [Universidade de Brasilia (UnB), DF (Brazil). Laboratorio de Geocronologia; Galli, Claudia Ines [Faculdad de Ingenieria, Universidad Nacional de Jujuy (Argentina); Coira, Beatriz [CIT Jujuy, CONICET. Instituto de Geologia y Mineria (Argentina); Alonso, Ricardo; Barrientos, Andrea [Instituto CEGA, CONICET. Universidad Nacional de Salta (Argentina)

    2015-07-01

    The Eocene of northwestern Argentina records complex basin and structural evolution, including continental sedimentation of the post-rift Salta Basin and the beginning of the Andean uplift and foreland system evolution. This illuminates a significant period of evolutionary history of this and surrounding basins in northwestern Argentina. U-Pb zircon analyses by LA-ICP-MS for three formations representing post-rift to foreland stages allowed interpretation about provenance terrains. The Lumbrera Formation, representing the post-rift stage, shows bimodal sources with a main zircon population around 462 Ma, and a second population around 1023 Ma. The Los Colorados and Angastaco Formations representing the sedimentation in a foreland basin, show a unimodal source around 490 Ma, and 517 Ma respectively. Zircons younger than 50 Ma were not identified during this study. (author)

  14. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  16. 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.

  17. 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.

  18. 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.

  19. Illustrated review of the leaf-mining Nepticulidae of the central Andes (Peru and Bolivia).

    Science.gov (United States)

    Stonis, Jonas R; Diškus, Arūnas; Remeikis, Andrius; Karsholt, Ole; Torres, Nixon Cumbicus

    2017-04-24

    We review forty-five species of Nepticulidae (Lepidoptera) based on an analysis of samples collected in the central Andean region of Peru and Bolivia. Thirteen of these species are new to science, and are named and described here: Stigmella paracosma Remeikis & Stonis, sp. nov., S. expressa Remeikis & Stonis, sp. nov., S. acalyphae Diškus & Stonis, sp. nov., S. lepida Diškus & Stonis, sp. nov., S. misera Diškus & Stonis, sp. nov., S. inca Diškus & Stonis, sp. nov., S. eiffeli Diškus & Stonis, sp. nov., S. arequipica Remeikis & Stonis, sp. nov., S. coronaria Diškus & Stonis, sp. nov., S. azulella Diškus & Stonis, sp. nov., S. sparsella Diškus & Stonis, sp. nov., Manoneura forcipis Diškus & Stonis, sp. nov., and Acalyptris murex Diškus & Stonis, sp. nov. Some of the central Andean species are recorded here as leaf-miners on Euphorbiaceae (Acalypha), Fabaceae (Collaea), Rosaceae (Polylepis), Malvaceae (Sida), Calceolariaceae (Calceolaria), Lamiaceae (Clinopodium), and Asteraceae (Ageratina and Trixis). We create eleven new species groups based on morphological characters designated in Stigmella and one in Acalyptris. A pictorial key to the species groups and distribution maps are provided. All new species are illustrated with 150 photographs and drawings of the adults and genitalia, and, where known and/or available, photographs of host-plants and leaf-mines.

  20. Recherches préliminaires en laboratoire sur les céramiques de Piruru (Andes Centrales

    Directory of Open Access Journals (Sweden)

    1985-01-01

    Full Text Available A partir de l'analyse par fluorescence X de 44 tessons de céramique provenant de la fouille de Piruru, et de 11 prélèvements d'argile recueillis tant à Piruru que dans la vallée du Tantamayo, est proposée une classification du matériel qui est représentée par un dendro-gramme. Cette première étude en laboratoire permet de réfléchir sur la validité des types céramiques déjà définis, et d'émettre des hypothèses de travail sur les structures de production et l'origine des céramiques. A partir del análisis por fluorescencia X de 44 tiestos de cerámica procedentes de la excavación de Piruru, y de 11 muestras de arcilla recogidas tanto en Piruru como en el valle del Tantamayo, se propone una clasificación del material que está representada por un dendrograma. Este primer estudio en laboratorio permite reflexionar sobre la validez de los tipos cerámicos ya definidos, y plantear hipótesis de trabajo sobre las estructuras de producción y el origen de las cerámicas.

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

    Directory of Open Access Journals (Sweden)

    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.

  2. 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...

  3. Vivid valleys, pallid peaks? Hypsometric variations and rural–urban land change in the Central Peruvian Andes

    Science.gov (United States)

    Haller, Andreas

    2012-01-01

    What happens to the land cover within the hinterland's altitudinal belts while Central Andean cities are undergoing globalization and urban restructuring? What conclusions can be drawn about changes in human land use? By incorporating a regional altitudinal zonation model, direct field observations and GIS analyses of remotely sensed long term data, the present study examines these questions using the example of Huancayo Metropolitano – an emerging Peruvian mountain city of 420,000 inhabitants, situated at 3260 m asl in the Mantaro Valley. The study's results indicate that rapid urban growth during the late 1980s and early 1990s was followed by the agricultural intensification and peri-urban condominization at the valley floor (quechua) – since the beginning of Peru's neoliberal era. Moreover, regarding the adjoining steep slopes (suni) and subsequent grassland ecosystems (puna), the research output presents land cover change trajectories that clearly show an expansion of human land use, such as reforestation for wood production and range burning for livestock grazing, even at high altitudes – despite rural–urban migration trends and contrary to several results of extra-Andean studies. Consequently, rural–urban planners and policy makers are challenged to focus on the manifold impacts of globalization on human land use – at all altitudinal belts of the Andean city's hinterland: toward sustainable mountain development that bridges the social and physical gaps – from the bottom up. PMID:23564987

  4. Vivid valleys, pallid peaks? Hypsometric variations and rural-urban land change in the Central Peruvian Andes.

    Science.gov (United States)

    Haller, Andreas

    2012-11-01

    What happens to the land cover within the hinterland's altitudinal belts while Central Andean cities are undergoing globalization and urban restructuring? What conclusions can be drawn about changes in human land use? By incorporating a regional altitudinal zonation model, direct field observations and GIS analyses of remotely sensed long term data, the present study examines these questions using the example of Huancayo Metropolitano - an emerging Peruvian mountain city of 420,000 inhabitants, situated at 3260 m asl in the Mantaro Valley. The study's results indicate that rapid urban growth during the late 1980s and early 1990s was followed by the agricultural intensification and peri-urban condominization at the valley floor ( quechua ) - since the beginning of Peru's neoliberal era. Moreover, regarding the adjoining steep slopes ( suni ) and subsequent grassland ecosystems ( puna ), the research output presents land cover change trajectories that clearly show an expansion of human land use, such as reforestation for wood production and range burning for livestock grazing, even at high altitudes - despite rural-urban migration trends and contrary to several results of extra-Andean studies. Consequently, rural-urban planners and policy makers are challenged to focus on the manifold impacts of globalization on human land use - at all altitudinal belts of the Andean city's hinterland: toward sustainable mountain development that bridges the social and physical gaps - from the bottom up.

  5. 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.

  6. 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)

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Mafic enclaves in dacitic domes and their relation with La Poruña scoria cone, Central Andes, northern Chile

    Science.gov (United States)

    González-Maurel, O. P.; Gallmeyer, G.; Godoy, B.; Menzies, A.; le Roux, P. J.; Harris, C.

    2017-12-01

    Chao Dacite, Chillahuita, Cerro Pabellón, Chanka, Chac-Inca, and Cerro La Torta (or Tocorpuri) are dacitic domes of late Pleistocene age (30 to 140 ka; Renzulli et al., 2006; Tierney et al., 2016) located in Northern Chilean Central Andean province (NCCA; 17°20'S - 27°40'S). While, La Poruña is a 180 m high basaltic-andesite scoria cone erupted ca. 100 ka (Wörner et al., 2000). This scoria cone is also located at the NCCA, 26 km to the SW of Chanka and 45 km to the NW of Chao Dacite. The dacitic domes are generally porphyritic and highly crystalline lavas (30 - 50 vol % phenocrysts, plagioclase > biotite > amphibole > quartz ≥ accessory), with hyalopilitic or intersertal groundmass. These domes contain mafic enclaves, mostly andesite in composition, with plagioclase > amphibole > biotite ≥ clinopyroxene ≥ olivine ≥ accessory phenocryst (10 - 20 vol %) in a lightly oxidized groundmass with intersertal or intergranular textures. In contrast, La Poruña rocks are mostly aphanitic (75 - 85 vol % groundmass) and highly vesicular, with plagioclase > olivine ≥ clinopyroxene ≥ orthopyroxene phenocrysts in an intersertal or hyalopilitic groundmass. Although petrographically different, the composition (57 wt % SiO2; 580 ppm Sr, 87Sr/86Sr = 0.7066) of mafic enclaves from Cerro Pabellón dome are similar to the lava flows and pyroclastic blocks of La Poruña scoria cone (55 - 59 wt % SiO2; 560 - 610 ppm Sr; 0.7062 - 0.7066 87Sr/86Sr). Based on this data and the eruption ages of these volcanic structures, we suggest that the mafic enclaves and La Poruña magmas are co-genetic. Thus, we propose that the genesis of these mafic enclaves is associated with the origin of less evolved parental magmas erupted in the NCCA, such as those from La Poruña. In this case, the mafic enclaves would represent batches of less evolved magmas that ascended from deeper sources and probably contributed in the eruption of the dacitic domes. Renzulli et al., 2006. In XI Congreso Geol

  9. 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

    Directory of Open Access Journals (Sweden)

    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

  10. Volcanic hotspots of the central and southern Andes as seen from space by ASTER and MODVOLC between the years 2000-2011

    Science.gov (United States)

    Jay, J.; Pritchard, M. E.; Mares, P. J.; Mnich, M. E.; Welch, M. D.; Melkonian, A. K.; Aguilera, F.; Naranjo, J.; Sunagua, M.; Clavero, J. E.

    2011-12-01

    We examine 153 volcanoes and geothermal areas in the central, southern, and austral Andes for temperature anomalies between 2000-2011 from two different spacebourne sensors: 1) those automatically detected by the MODVOLC algorithm (Wright et al., 2004) from MODIS and 2) manually identified hotspots in nighttime images from ASTER. Based on previous work, we expected to find 8 thermal anomalies (volcanoes: Ubinas, Villarrica, Copahue, Láscar, Llaima, Chaitén, Puyehue-Cordón Caulle, Chiliques). We document 31 volcanic areas with pixel integrated temperatures of 4 to more than 100 K above background in at least two images, and another 29 areas that have questionable hotspots with either smaller anomalies or a hotspot in only one image. Most of the thermal anomalies are related to known activity (lava and pyroclastic flows, growing lava domes, fumaroles, and lakes) while others are of unknown origin or reflect activity at volcanoes that were not thought to be active. A handful of volcanoes exhibit temporal variations in the magnitude and location of their temperature anomaly that can be related to both documented and undocumented pulses of activity. Our survey reveals that low amplitude volcanic hotspots detectable from space are more common than expected (based on lower resolution data) and that these features could be more widely used to monitor changes in the activity of remote volcanoes. We find that the shape, size, magnitude, and location on the volcano of the thermal anomaly vary significantly from volcano to volcano, and these variations should be considered when developing algorithms for hotspot identification and detection. We compare our thermal results to satellite InSAR measurements of volcanic deformation and find that there is no simple relationship between deformation and thermal anomalies - while 31 volcanoes have continuous hotspots, at least 17 volcanoes in the same area have exhibited deformation, and these lists do not completely overlap. In

  11. Eruption and Degassing Processes in a Supervolcanic System: The Volatile Record Preserved in Melt Inclusions from the 3.49Ma Tara Ignimbrite in the Central Andes

    Science.gov (United States)

    Grocke, S.; de Silva, S. L.; Schmitt, A. K.; Wallace, P. J.

    2010-12-01

    Analysis of H2O and CO2 in quartz and sanidine-hosted melt inclusions from one of the youngest supervolcanic eruptions in the Altiplano Puna Volcanic Complex (APVC) in the Central Andes provides information on crystallization depths and eruption and degassing processes. At least 740 km3 of high-K, metaluminous, rhyodacite to rhyolite magma erupted from the Guacha Caldera in southwest Bolivia, producing three phases of the 3.49 Ma Tara Ignimbrite: a Plinian fall-deposit, an extensive ignimbrite, and several post-caldera domes. Infrared spectroscopic analyses of quartz-hosted melt inclusions from Tara Plinian pumice have H2O contents of ~4.5 wt % and variable CO2 contents (110-300 ppm), corresponding to vapor saturation pressures up to 180 MPa. In contrast, sanidine-hosted melt inclusions from the Plinian-fall deposit contain bubbles, lower water contents (1.4-2.2 wt %) and lower CO2 (87-143 ppm). These vesiculated melt inclusions and low volatile contents suggest that the sanidine crystals leaked on their ascent to the surface and therefore do not record accurate pre-eruptive melt volatile contents. In contrast, quartz-hosted melt inclusions from post-caldera dome samples contain lower H2O contents of 2.5-3.5 wt % (average 2.9 wt %) and no detectable CO2, corresponding to vapor saturation pressures of 50-90 MPa. These data indicate that the preeruptive plinian stage Tara magma was vapor saturated at the time of melt inclusion entrapment and stored between 5-6 km, while those from the post-caldera domes were trapped at 2-3 km. Differences in CO2 between Plinian and dome melt inclusions require that the post-caldera dome quartzes represent a different generation of crystals that grew as the magma slowly rose and progressively degassed at 2-3 km. During this shallow crystallization, the magma evolved further and eventually fed the post-caldera domes, one of which is a high-Si rhyolite. Consistent with this interpretation, melt inclusions from post-caldera dome samples

  12. 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

  13. 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

    Directory of Open Access Journals (Sweden)

    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.

  14. 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

    Directory of Open Access Journals (Sweden)

    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.

  15. 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

  16. 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

  17. 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

    Directory of Open Access Journals (Sweden)

    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.

  18. Evidence for Cenozoic extensional basin development and tectonic inversion south of the flat-slab segment, southern Central Andes, Chile (33° 36°S.L.)

    Science.gov (United States)

    Charrier, R.; Baeza, O.; Elgueta, S.; Flynn, J. J.; Gans, P.; Kay, S. M.; Muñoz, N.; Wyss, A. R.; Zurita, E.

    2002-04-01

    . Tectonic and volcanic events on the east versant of the Andes [Journal of South American Earth Sciences 15 (2002)], which are coeval with the basin inversion and crustal thickening episodes presented herein and, therefore, with the previously mentioned period of increasing convergence rate, are assumed to correspond with the same episode of major tectonic accommodation of the crust in this Andean region. It is not yet possible to determine if the collisional event of the Juan Fernández ridge at approximately 15 Ma in the flat-slab segment region had a local or a more regional effect on the late Cenozoic tectonic evolution of the continental margin in the Central Andes.

  19. 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.

  20. 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.

  1. Present and future water resources supply and demand in the Central Andes of Peru: a comprehensive review with focus on the Cordillera Vilcanota

    Science.gov (United States)

    Drenkhan, Fabian; Huggel, Christian; Salzmann, Nadine; Giráldez, Claudia; Suarez, Wilson; Rohrer, Mario; Molina, Edwin; Montoya, Nilton; Miñan, Fiorella

    2014-05-01

    Glaciers have been an important element of Andean societies and livelihoods as direct freshwater supply for agriculture irrigation, hydropower generation and mining activities. Peru's mainly remotely living population in the Central Andes has to cope with a strong seasonal variation of precipitations and river runoff interannually superimposed by El Niño impacts. Direct glacier and lake water discharge thus constitute a vital continuous water supply and represent a regulating buffer as far as hydrological variability is concerned. This crucial buffer effect is gradually altered by accelerated glacier retreat which leads most likely to an increase of annual river runoff variability. Furthermore, a near-future crossing of the 'peak water' is expected, from where on prior enhanced streamflow decreases and levels out towards a new still unknown minimum discharge. Consequently, a sustainable future water supply especially during low-level runoff dry season might not be guaranteed whereas Peru's water demand increases significantly. Here we present a comprehensive review, the current conditions and perspectives for water resources in the Cusco area with focus on the Vilcanota River, Cordillera Vilcanota, Southern Peru. With 279 km2 the Cordillera Vilcanota represents the second largest glacierized mountain range of the tropics worldwide. Especially as of the second half of the 1980s, it has been strongly affected by massive ice loss with around 30% glacier area decline until present. Furthermore, glacier vanishing triggers the formation of new lakes and increase of lake levels and therefore constitutes determining hazardous drivers for mass movements related to deglaciation effects. The Vilcanota River still lacks more profound hydrological studies. It is likely that its peak water has already been or might be crossed in near-future. This has strong implications for the still at 0.9% (2.2%) annually growing population of the Cusco department (Cusco city). People mostly

  2. Frugivoría y dispersión de semillas de la palma Oenocarpus bataua (Arecaceae en un bosque de los Andes colombianos Frugivory and seed dispersal Oenocarpus bataua palm (Arecaceae in a forest from the Colombian Andes

    Directory of Open Access Journals (Sweden)

    Rosario Rojas-Robles

    2012-12-01

    Full Text Available En zonas bajas tropicales, en bosques continuos y relativamente poco intervenidos, los frutos de la palma Oenocarpus bataua Mart., son consumidos por diversas especies de vertebrados, sin embargo, no hay estudios de dispersión de más largo plazo con esta especie. Entre agosto 2005-septiembre 2006 se realizaron observaciones de remoción de frutos, conteo de frutos comidos, observaciones focales, registros de frugivoría mediante trampas fotográficas, experimentos de dispersión y parcelas para determinar distribución espacial de Oenocarpus bataua. Cinco especies de mamíferos comen, dispersan, entierran (Sciurus granatensis, Microsciurus mimulus, Dasyprocta punctata y Proechimys sp., tapan (Marmosa robinsoni y llevan a las cuevas (Marmosa robinsoni y Proechimys sp., los frutos de O. bataua, sin dañar la semilla. El 21.7% de los frutos fueron dispersados, 13.2% roídos o pelados, 5.6% tapados, enterrados y llevados a cuevas. La distancia media de remoción de semillas y frutos fue 3.1m, aunque en menor proporción se registraron eventos de dispersión > a 50m. La abundante producción, el tamaño, el peso, la intensa remoción de los frutos por frugívoros, las cortas distancias de dispersión, la ausencia de frugívoros de gran porte disminuidos por cacería y fragmentación, encargados de la dispersión de larga distancia y el aumento de roedores, especialmente ardillas que presionan fuertemente el recurso frutos, generan una lluvia de semillas espacialmente restringida, posiblemente responsable de los patrones de distribución agregados en semillas, plántulas y posteriormente en juveniles y sub-adultos.Seed dispersal is a key process that determines the spatial structure and dynamics of populations of plants, establishes the potential area of recruitment and in this way, the basis for subsequent processes such as predation, germination, competition and growth. The purpose of this research was to identify the guild of frugivores of the

  3. 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.

  4. Importancia de la heterogeneidad de hábitats para la biodiversidad de hormigas en los Andes de Colombia Importance of habitat heterogeneity for ant biodiversity in the Colombian Andes

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    Mónica Ramírez Ramírez

    2009-04-01

    Full Text Available Entre marzo y octubre de 2002 se compararon los ensamblajes de hormigas que forrajean en el suelo en un sistema no manejado (reserva natural El Ciprés y en algunas fincas vecinas. En dos transectos de 100 m se instalaron estaciones de muestreo cada 10 m con trampa de caída (pitfall y cebo de atún epígeo durante 880 h y 92 días respectivamente. En 1471 eventos de captura se determinaron 68 especies distribuidas en 26 géneros y 8 subfamilias. En el sistema silvopastoril- guayaba y en monocultivo de granadilla (Passiflora ligularis dominaron las especies de hormigas mientras que la distribución fue más equitativa en los usos del terreno con estructura vegetal más compleja (bosque, café, sucesión temprana y banco de forrajes. El sistema silvopastoril-guayaba fue el más rico en especies (31 seguido por café (30 y por el bosque y la sucesión temprana (29. El flujo de especies fue alto en bosque, café y sucesión temprana, indicando que la calidad de la matriz es factor importante para el mantenimiento de la biodiversidad.In order to compare the ant assamblages in the Natural Reserve El Ciprés (Valle- Colombia and its neighboring farms, periodical ant sampling was carried out between March and October 2002. Each site had two transects of 100m with 10 sampling points. Each sampling point contained a pitfall trap and epigeal tuna bait established for 880 h and 92 days, respectively. In addition, the vegetal structure of each place was characterised. A total of 1471 ants were collected representing 68 species in 26 genera and 8 subfamilies. Two agricultural systems, the silvopastoral guava and passion fruit (Passiflora ligularis monoculture, typically presented ant species that over numbered other species whereas sites with more complex vegetation structure (i.e. forest, coffee, early succession and fodder banks had a more equitable distribution for the ant species. In terms of ant richness, the guava system was the richest (31 spp

  5. Diversidad de mariposas (Lepidoptera, Papilionoidea y su relación con el paisaje de alta montaña en los Andes nororientales de Colombia

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    Olarte-Quiñonez, C. A.

    2016-09-01

    Full Text Available Diversity of butterflies (Lepidoptera, Papilionoidea and their relationship with the highlands’ landscape in the northeastern Andes of Colombia The Andean region harbors a great variety of ecosystems, including the characteristic high mountain zones. The biological diversity in these zones, however, is declining as the result of changes in land use, particularly the introduction of agriculture and cattle ranching. Changes in the high mountain landscape can be appropriately monitored using diversity indicators such as butterflies, one of the most important indicator species. We chose twelve sampling points in the paramo (high altitude moor complexes Almorzadero, Santurbán and El Tamá, located in the northeastern region of Colombia to collect adult butterflies within transects of 100 x 4 m, along an altitudinal gradient of 500 m. We recorded 69 species, from five families. Diversity values of the diurnal butterfly communities varied among the different areas of vegetation coverage associated with each transect. Conserved vegetation coverage (i.e. dense forest, scrublands and scrublands, and paramo and subparamo showed the highest values of diversity, while perturbed coverage (i.e. fragmented forests, pastures and agriculture areas presented the lowest values of diversity. Analysis of the community structure showed that endemic butterfly species were associated with fragmented areas in the high mountains. Findings from this study, the first of its kind to determine changes in butterfly diversity in highlands in northeastern Colombia, may help to generate conservation strategies in places where there is high endemism and diversity

  6. 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.

  7. Transferencia de metales de suelo a planta en áreas mineras: Ejemplos de los Andes peruanos y de la Cordillera Prelitoral Catalana

    OpenAIRE

    Durán Cuevas, Paola

    2011-01-01

    Las actividades mineras generan una elevada cantidad de residuos metálicos que contaminan el suelo ya sea química, física y/o biológicamente. Estos residuos pueden permanecer en el suelo por un largo plazo. Esta permanencia es especialmente grave en el caso de los compuestos inorgánicos como es el caso de los metales pesados, que no pueden ser degradados. Su persistencia, acumulación progresiva y/o su transferencia a las cadenas tróficas pone en riesgo a la salud humana, animal y la de los ec...

  8. 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...

  9. A través de los Andes: Estrategias sociales y redes de poder entre Córdoba y Huancavelica en el siglo XVIII

    OpenAIRE

    Márquez, María Victoria

    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...

  10. Complicaciones mecánicas de los accesos venosos centrales

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    Dr. T. Rodrigo Rivas

    2011-05-01

    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, trombosis venosa asociada a catéter venoso central (CVC y oclusión del CVC; algunos elementos de prevención, diagnóstico y tratamiento así como el impacto que puede tener la ultrasonografía rutinaria para instalar un CVC.

  11. 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

  12. 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...

  13. A TRAVÉS DE LOS ANDES. ESTRATEGIAS SOCIALES Y REDES DE PODER ENTRE CÓRDOBA Y HUANCAVELICA EN EL SIGLO XVIII

    Directory of Open Access Journals (Sweden)

    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.

  14. LOS INTERESES DE CHINA EN ASIA CENTRAL, BELT AND ROAD

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    Antonio Alonso

    2017-10-01

    Full Text Available China´s interests in Central Asia were propelled, with the launching of the initiative “One Belt, One Road”, renamed as “The Belt and Road Initiative”, better known as the New Silk Road. Thanks to the infrastructure investment China will become interconnected with other regions of the world, breaking up its secular isolation and will send its products to the global market more easily by land and sea. One principal question in this revolutionary change has to do with China´s hypothetical second intentions of geopolitical influence on the countries affected by the new routes (countries of transit or final destination. The article tries to answer the following questions: Does the People's Republic of China aim only to revive its internal labour market, reduce its industrial overcapacity and boost its exports? Is globalization coming to an end or is it entering a new phase of interconnectivity? How does this affect the relations between Russia and China in the Asian region?

  15. 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

  16. 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.

  17. Aymaras, peruanos y chilenos en los Andes ariqueños: Resistencia y conflicto frente a la chilenización del norte de Chile

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    Alberto Díaz Araya

    2006-05-01

    Full Text Available Este artículo reflexiona desde un punto de vista de la antropología histórica las reacciones y articulaciones que generaron las comunidades Aymaras del área de Arica entre los años 1901 y 1926, periodo reconocido como “chilenización”, ante la presencia del Estado chileno, asumiendo posturas identitarias sociopolíticas en un ambiente de conflicto nacional.

  18. BIOLOGÍA REPRODUCTIVA Y ECOLOGÍA DE LA POLINIZACIÓN DE LA PALMA MILPESOS OENOCARPUS BATAUA EN LOS ANDES COLOMBIANOS

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    NÚÑEZ-AVELLANEDA LUIS ALBERTO

    2008-07-01

    Full Text Available Entre agosto de 2005 y julio de 2006 estudiamos la fenología, la biología floral y elsistema reproductivo de una población de Oenocarpus bataua (Palmae en los Andescolombianos. Evaluamos el sistema de polinización y determinamos la abundancia,el comportamiento y la eficiencia de los polinizadores. La población floreció a lolargo del año con un pico entre diciembre y enero. Cada inflorescencia pasa poruna fase masculina, una intermedia no reproductiva y una fase femenina. La antesisocurre en la noche, con producción de aromas y aumento en la temperatura de lasinflorescencias. Durante la fase masculina la temperatura de la inflorescencia fue 5.8ºC, mayor que la temperatura ambiental y mayor que el aumento de la temperaturaen la fase femenina 4.2 ºC. El aroma floral está compuesto predominantemente porα-gurjuneno, ciclozativeno y trans-cariofileno. Las flores fueron visitadas por 81especies de artrópodos, principalmente de Coleópteros. Las inflorescencias en fasemasculina son visitadas en busca de alimento (polen, tejidos vegetales, presa ylugar para apareamiento. Las flores femeninas no ofrecen recompensas y atraen a lospolinizadores por mimetismo químico. La similitud entre los compuestos químicosdel aroma de las inflorescencias en fase masculina y femenina de O. bataua es alta(92%, como ocurre en otras especies de palmas. O. bataua es monoica, xenogámica,autoincompatible y dicogámica con protandria marcada. No encontramos evidenciade transporte de polen a grandes distancias por el viento y al parecer la polinizaciónes principalmente por Coleópteros. Las siguientes especies fueron los polinizadoresmás efectivos, Baridinae Gen 4, sp. 1, Phyllotrox sp. 35, Anchylorhynchus sp.2, Anchylorhynchus tricarinatus (Curculionidae y Mystrops sp. 1 (Nitidulidae,los cuales son responsables del 97 % del flujo de polen entre inflorescencias. Ladependencia mutua, el grado de interrelación y la distribución geográfica similarentre O. bataua

  19. 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.

  20. Efecto de la tala de Podocarpus glomeratus (Podocarpaceae sobre la estructura de un bosque de neblina en los Andes (Cochabamba, Bolivia

    Directory of Open Access Journals (Sweden)

    Ariel Isaías Ayma-Romay

    2011-07-01

    Full Text Available En el presente trabajo fueron analizados los efectos de la tala sobre la estructura, composición y la regeneración natural de un bosque andino de neblina. Se instalaron 40 parcelas de 707 m2 para medir individuos >10 cm DAP y sub-parcelas de 5 m2 para evaluar la regeneración de individuos <10 cm DAP y de 1 m2 para evaluar el banco de semillas. Se evaluó la densidad y cobertura de todos los árboles. Se realizó un análisis cluster para establecer las categorías de cobertura de dosel y un análisis de componentes principales para determinar su asociación con la densidad de diferentes especies de plántulas. La tala ha modificado la cobertura (p= <0,001 generando doseles de poco a fuertemente intervenidos. Los claros de dosel favorecen a las heliófitas (Myrsine pseudocrenata, Vallea stipularis, Nectandra sp., Trichilia hirta, Miconia theaezans, algunas esciófitas que requieren luz en clases avanzadas (Podocarpus glomeratus y Myrcianthes osteomeloides y otros arbustos (Solanaceae, Verbenaceae y otras. Por otra parte, algunas esciófitas reducen su densidad en doseles inter- venidos (Weinmannia microphylla, Condalia weberbaueri, Blepharocalix salicifolius y Styloceras columnare. El manejo del bosque debe mantener la cobertura de individuos > 60 cm DAP, la creación de reservas en bosques maduros y prácticas de facilitación para el crecimiento de especies de árboles claves.

  1. Distribución espacial y ciclo diurno de la temperatura ambiente y punto de rocio en una región de los Andes Tropicales de Colombia.

    OpenAIRE

    Jiménez Ramírez, Johanna P.; Marín Arroyave, Lina María; Moreno Ramírez, Hernán Alonso; Vélez Upegui, Jaime Ignacio; Guzman Sossa, José Vicente; Poveda Jaramillo, Germán

    2004-01-01

    Con el propósito de cuantificar la disponibilidad del recurso de agua atmosférica proveniente de la condensación del vapor de agua en la atmósfera inferior, se estudia la variabilidad espacial de la temperatura en una región comprendida entre 5º N a 7º N y 75º W a 76º W. Se estiman relaciones entre los valores promedio de largo plazo de la temperatura del aire y la temperatura de rocío, con la altura sobre el nivel del mar, encontrándose altos coeficientes de determinación. Se identifican dif...

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

    Directory of Open Access Journals (Sweden)

    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.

  3. 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

  4. Nueva localidad para Alsodes tumultuosus Veloso, Iturra & Galleguillos, 1979 (Amphibia, Alsodidae en la Cordillera de los Andes, Region de O’Higgins, Chile

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    Diego Ramírez Álvarez

    2015-06-01

    Full Text Available Alsodes tumultuosus Veloso, Iturra & Galleguillos, 1979 es un anfibio endémico de Chile, descrito y hasta hace poco conocido únicamente en su localidad tipo, los arroyos cordilleranos del Sector La Parva, en la región Metropolitana. En este artículo se detalla el hallazgo de una nueva localidad para esta especie, en la región de O’Higgins, aproximadamente a 100 kilómetros al sur de La Parva. Este hallazgo, sugiere la ampliación del rango de distribución de esta especie al cordón cordillerano Andino de la región de O’Higgins, y señala la necesidad de efectuar mayores prospecciones e investigación de la especie, que permitan definir claramente su estado de conservación en Chile.

  5. 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

  6. 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.

    Science.gov (United States)

    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

  7. Beliefs about the causes of schizophrenia among Aymara and non-Aymara patients and their primary caregivers in the Central-Southern Andes.

    Science.gov (United States)

    Caqueo-Urízar, Alejandra; Breslau, Joshua; Gilman, Stephen E

    2015-02-01

    The aim of this study is to investigate differences in the beliefs about the causes of schizophrenia between Aymara and non-Aymara patients with schizophrenia and their primary caregivers. Ethnic background plays an important role in the formation of beliefs regarding the causes of schizophrenia, and there have been no prior studies on such beliefs among the Aymara, an indigenous community with a population of about 2 million people living in the Andes. We focused on three systems of beliefs distinguished in the literature: biological, psychosocial and magical-religious. The sample comprised 253 patients (n=117 Aymara, and n=136 non-Aymara) of public mental health centers in Chile (33.6%), Peru (33.6%) and Bolivia (32.8%) with a diagnosis of schizophrenia, and each patient's primary caregiver. We administered to patients and caregivers a questionnaire with scales assessing the perceived causes of schizophrenia. Linear regression models were fitted to compare differences in the levels of causal beliefs between Aymara and non-Aymara patients and caregivers, and to identify socio-demographic and clinical predictors of different types of beliefs about the causes of schizophrenia. Adjusted for socio-demographic and clinical covariates, levels of psychosocial beliefs were significantly higher for Aymara caregivers (0.33, 95% confidence interval (CI)=0.05, 0.62) than non-Aymara caregivers. Contrary to expectations, beliefs about the causes of schizophrenia among Aymara are not more magical-religious than those of their non-Aymara counterparts. It may be necessary for mental health staff members to evaluate beliefs about the disorder, especially in ethnic minorities, before applying a standard model of treatment. © The Author(s) 2014.

  8. Late Oligocene-Early Miocene compressional tectosedimentary episode and associated land-mammal faunas in the Andes of central Chile and adjacent Argentina (32 37°s)

    Science.gov (United States)

    Semper, Thierry; Marshall, Larry G.; Rivano, Sergio; Godoy, Estanislao

    1994-01-01

    A reassessment of the geologic and land-mammal fossil evidence used in attribution of a tectosedimentary episode in the Andes between 32 and 37°S to the Middle Eocene "Incaic tectonic phase" of Peru indicates that the episode occurred during Late Oligocene-Early Miocene times(~ 27-20 Ma). From west to east, three structural domains are recognized for this time span in the study area: a volcanic arc (Chile); a thin-skinned, E-verging fold-thrust belt (Cordillera Principal, Chile-Argentina border strip); and a foreland basin (Argentina). Initiation of thrusting in the Cordillera Principal fold-thrust belt produced the coeval initiation of sedimentation in the foreland basin of adjacent Argentina. This onset of foreland deposition postdates strata bearing a Divisaderan Land Mammal Age fauna (i.e. ~ 35-30 Ma) and is marked at ~ 36°30'S by the base of the "Rodados Lustrosos" conglomerates, which are conformably overlain by sedimentary rocks containing a Deseadan Land Mammal Age fauna (i.e. ~ 29-21 Ma). Geologic relationships between the thick volcanic Abanico (Coya-Machalí) and Farellones formations also demonstrate that this tectosedimentary episode practically ended at ~ 20 Ma at least in the volcanic arc, and was therefore roughly coeval with the major tectonic crisis (~ 27-19 Ma) known in northwestern Andean Bolivia some 1500 km to the north. This strongly suggests that a long, outstanding tectonic upheaval affected at least an extended 12-37°S segment of the Andean margin of South America during Late Oligocene and Early Miocene times.

  9. Composición química y actividad antibacteriana del aceite esencial de Peperomia acuminata de los Andes venezolanos

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    Flor D. Mora-Vivas

    2016-12-01

    Full Text Available El género Peperomia (Piperaceae, es bien conocido por sus especies ornamentales y usos etnomedicinales. En el presente trabajo se describe la caracterización química y la actividad antibacteriana del aceite esencial de Peperomia acuminata Ruiz & Pav. proveniente del Estado Mérida Venezuela. El aceite esencial se obtuvo por hidrodestilación de las hojas y la separación de los componentes se realizó por Cromatografía de gases-Espectrometría de Masas (CG/EM. Se logró la elucidación de ocho compuestos (96,7%, siendo el 2E-dodecenal el componente mayoritario (65% seguido de dodecanal (14,8% y tetradecanal (9,2%. Esta investigación muestra el potencial del aceite esencial de P. acuminata frente a bacterias Gram positivas (Staphylococcus aureus ATCC 25923 y Enterococcus faecalis 29212, con un valor de Concentración inhibitoria mínima de 1μL/mL. Este es el primer reporte sobre la composición química del aceite esencial de esta especie, por lo tanto una contribución importante al estudio del género Peperomia.

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

    Directory of Open Access Journals (Sweden)

    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

  11. Un pensador Aristocrático en los Andes: Una mirada al pensamiento de Nicolás Gómez Dávila.

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    Mauricio Galindo Hurtado.

    2000-06-01

    Full Text Available Sobresaliente en el panorama intelectual colombiano es la figura de Nicolás Gómez Dávila. Este escritor sabanero es tal vez la única voz que, en forma explicita y magistral, se propuso desmenuzar el pensamiento occidental asumiendo la postura del reaccionario. Gómez Dávila deja, al morir, un libro en cinco etapas, colección de aforismos qúe insiste en llamar escolios, en los cuales discurre sobre la filosofía, la moral, la estética, la historia y la literatura de más de dos mil años de civilización grecolatina. La obra de Gómez Dávila posee la convicción dogmática del reaccionario que condena con juicios enfáticos las glorias del hombre "moderno". Hay allí ecos de una visión hispánica de Contra Reforma que influyó no poco en buena parte de las elites colombianas. Mas es también un llamado a la sensibilidad y a la belleza, un recordatorio que más allá de un conocimiento racional y científico, está la dimensión de la persona humana que ningún sistema puede abarcar. Férreo defensor de un libre albedrío enmarcado en un exigente universo moral, su voz incita al despliegue máximo de la inteligencia, inigualable herramienta para alzar vuelo sobre realidades pedestres.

  12. 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

    OpenAIRE

    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 ...

  13. The Amazon-Laurentian connection as viewed from the Middle Proterozoic rocks in the central Andes, western Bolivia and northern Chile

    Science.gov (United States)

    Tosdal, R.M.

    1996-01-01

    Middle Proterozoic rocks underlying the Andes in western Bolivia, western Argentina, and northern Chile and Early Proterozoic rocks of the Arequipa massif in southern Peru?? from the Arequipa-Antofalla craton. These rocks are discontinuously exposed beneath Mesozoic and Cenozoic rocks, but abundant crystalline clasts in Tertiary sedimentary rocks in the western altiplano allow indirect samples of the craton. Near Berenguela, western Bolivia, the Oligocene and Miocene Mauri Formation contains boulders of granodiorite augen gneiss (1171??20 Ma and 1158??12 Ma; U-Pb zircon), quartzose gneiss and granofels that are inferred to have arkosic protoliths (1100 Ma source region; U-Pb zircon), quartzofeldspathic and mafic orthogneisses that have amphibolite- and granulite-facies metamorphic mineral assemblages (???1080 Ma metamorphism; U-Pb zircon), and undeformed granitic rocks of Phanerozoic(?) age. The Middle Proterozoic crystalline rocks from Berenguela and elsewhere in western Bolivia and from the Middle Proterozoic Bele??n Schist in northern Chile generally have present-day low 206Pb/204Pb ( 15.57), and elevated 208Pb/204Pb (37.2 to 50.7) indicative of high time-averaged Th/U values. The Middle Proterozoic rocks in general have higher presentday 206Pb/204Pb values than those of the Early Proterozoic rocks of the Arequipa massif (206Pb/204Pb between 16.1 and 17.1) but lower than rocks of the southern Arequipa-Antofalla craton (206Pb/204Pb> 18.5), a difference inferred to reflect Grenvillian granulite metamorphism. The Pb isotopic compositions for the various Proterozoic rocks lie on common Pb isotopic growth curves, implying that Pb incorporated in rocks composing the Arequipa-Antofalla craton was extracted from a similar evolving Pb isotopic reservoir. Evidently, the craton has been a coherent terrane since the Middle Proterozoic. Moreover, the Pb isotopic compositions for the Arequipa-Antofalla craton overlap those of the Amazon craton, thereby supporting a link

  14. Body image dissatisfaction and low self-esteem due to physical appeareance in students of the faculty of medicine at the university of los andes (mérida, venezuela

    Directory of Open Access Journals (Sweden)

    Pedro López Atencio

    2008-07-01

    Full Text Available The purpose of this investigation was to evaluate body image dissatisfaction in relation to low self-esteem due to physical appearance in students of the Faculty of Medicine at the University of Los Andes in Mérida, Venezuela.  It was a non-experimental and correlational study.  The sample included 189 students (27% male and 73% female with an average age of 19.58 ± 1.57 (men: 19.81 years of age ± 1.74 and women: 20.24 years of age ± 1.76.  Participants were intentionally selected from first-year courses of the Medicine, Nursing and Nutrition programs.  The Body Shape Questionnaire (BSQ (Cooper and Taylor, 1987 was the instrument used to measure body image dissatisfaction and Graffar’s modified method (Méndez and De Méndez, 1994 was applied to determine the participants’ socioeconomic status.  A descriptive analysis (frequency, percentages, mean and an inferential analysis (one-way ANOVA were applied to the data using SPSS (Statistical Package for Social Sciences version 9.0.  One of the most important findings in this study was the determination of a statistically significant relationship between dissatisfaction and body image and between low self-esteem and gender χ2 (2, N= 189 = 9.686, p=0.008.  Using ANOVA also helped determine that differences in the mean for dissatisfaction and low self-esteem levels with body image and gender are statistically significant, F= 11.236; p=0.008, F=10.23; p=0.002, respectively.  Conclusions: results obtained suggest a relationship between dissatisfaction and low self-esteem due to physical appearance. Consequently, subjects reject their body image because of a distorted or undistorted perception of their physical appearance, which can possibly affect self-esteem.  Moreover, it is observed that the students’ psychological health is more related to their satisfaction with their body-image than to the way their body image is perceived. Consequently, this group of participants must be

  15. 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

  16. 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.

  17. 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

  18. "Comprender los rituales ganaderos en los Andes y más allá. Etnografías de lidias herranzas y arrierías". Juan Javier Rivera Andía (ed.

    Directory of Open Access Journals (Sweden)

    Héctor Manuel Medina Miranda

    2015-12-01

    Full Text Available El estudio de las prácticas ganaderas en las sociedades amerindias nos obliga, en todos los casos, a atestiguar la avidez con la que dichos grupos se apropiaron de los animales que no existían en el “nuevo continente”. Nos apremia a contemplar la capacidad de innovación indígena, que sin dilación incluyó a los nuevos ganados en las prácticas rituales y el pensamiento mítico preexistente. En algunas regiones de América, hablar de “ganadería prehispánica” equivaldría a disertar acerca de la “hípica azteca”, la “urbanística gitana”, la “agricultura antártica” o cualquier otra de las asignaturas imposibles que Umberto Eco imaginara para su novela El péndulo de Foucault. Sin embargo, este no es el caso de la región andina, donde la crianza de camélidos –principalmente la llama y la alpaca– han ocupado un lugar por demás importante desde tiempos inmemorables.

  19. 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.

  20. 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

  1. 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

    Directory of Open Access Journals (Sweden)

    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.

  2. Geomorphic evidence for post-10 Ma uplift of the western flank of the central Andes 18°30'-22°S

    Science.gov (United States)

    Hoke, Gregory D.; Isacks, Bryan L.; Jordan, Teresa E.; Blanco, NicoláS.; Tomlinson, Andrew J.; Ramezani, Jahandar

    2007-10-01

    The western Andean mountain front forms the western edge of the central Andean Plateau. Between 18.5° and 22°S latitude, the mountain front has ˜3000 m of relief over ˜50 km horizontal distance that has developed in the absence of major local Neogene deformation. Models of the evolution of the plateau, as well as paleoaltimetry estimates, all call for continued large-magnitude uplift of the plateau surface into the late Miocene (i.e., younger than 10 Ma). Longitudinal river profiles from 20 catchments that drain the western Andean mountain front contain several streams with knickpoint-bounded segments that we use to reconstruct the history of post-10 Ma surface uplift of the western flank of the central Andean Plateau. The generation of knickpoints is attributed to tectonic processes and is not a consequence of base level change related to Pacific Ocean capture, eustatic change, or climate change as causes for creating the knickpoint-bounded stream segments observed. Minor valley-filling alluvial gravels intercalated with the 5.4 Ma Carcote ignimbrite suggest uplift related river incision was well under way by 5.4 Ma. The maximum age of river incision is provided by the regionally extensive, approximately 10 Ma El Diablo-Altos de Pica paleosurface. The river profiles reveal that relative surface uplift of at least1 km occurred after 10 Ma.

  3. Cenozoic sedimentation and exhumation of the foreland basin system preserved in the Precordillera thrust belt (31-32°S), southern central Andes, Argentina

    Science.gov (United States)

    Levina, Mariya; Horton, Brian K.; Fuentes, Facundo; Stockli, Daniel F.

    2014-09-01

    Andean retroarc compression associated with subduction and shallowing of the oceanic Nazca plate resulted in thin-skinned thrusting that partitioned and uplifted Cenozoic foreland basin fill in the Precordillera of west-central Argentina. Evolution of the central segment of the Precordillera fold-thrust belt is informed by new analyses of clastic nonmarine deposits now preserved in three intermontane regions between major east directed thrust faults. We focus on uppermost Oligocene-Miocene basin fill in the axial to frontal Precordillera at 31-32°S along the Río San Juan (Albarracín and Pachaco sections) and the flank of one of the leading thrust structures (Talacasto section). The three successions record hinterland construction of the Frontal Cordillera, regional arc volcanism, and initial exhumation of Precordillera thrust sheets. Provenance changes recorded by detrital zircon U-Pb age populations suggest that initial shortening in the Frontal Cordillera coincided with an early Miocene shift from eolian to fluvial accumulation in the adjacent foreland basin. Upward coarsening of fluvial deposits and increased proportions of Paleozoic clasts reflect cratonward (eastward) advance of deformation into the Precordillera and resultant structural fragmentation of the foreland basin into isolated intermontane segments. Apatite (U-Th)/He thermochronometry of basin fill constrains to 12-9 Ma the most probable age of uplift-induced exhumation and cooling of Precordillera thrust sheets. This apparent pulse of exhumation is evident in each succession, suggestive of rapid, large-scale exhumation by synchronous thrusting above a single décollement linking major structures of the Precordillera.

  4. Hermes Tovar Pinzón. Los fantasmas de la memoria. Poder e inhibición en la historia de América Latina. Bogotá: Universidad de los Andes, 2009. 392 páginas

    Directory of Open Access Journals (Sweden)

    Renán Vega Cantor

    2015-07-01

    Full Text Available En 1976, Darío Jaramillo Agudelo acuñó el apelativo de nueva historia en un libro que compiló, que se convirtió en algo así como el manifiesto inaugural de lo que luego se llamaría, de manera cuasi oficial, La nueva historia de Colombia, y cuya producción más reconocida se plasmó en el libro mencionado, junto con el Manual de historia de Colombia en tres volúmenes, editado por Colcultura, y en Colombia hoy, un pequeño volumen publicado por la Editorial Siglo XXI, en 1978. En estos libros aparecen escritos de académicos que emergían o se autoproclamaban, en ese momento, como lo más novedoso e innovador de una investigación histórica que se pretendía independiente del bipartidismo e, incluso, crítica del capitalismo salvaje, a la colombiana. Los nombres más representativos, tal como aparecen en los libros mencionados, eran Jorge Orlando Melo, Álvaro Tirado Mejia, Salomón Kalmanovitz, Jesús Antonio Bejarano, Miguel Urrutia, Germán Colmenares y su mentor intelectual, Jaime Jaramillo Uribe. El nombre de Hermes Tovar Pinzón, un historiador de la misma generación, cuya producción intelectual ya era notable desde finales de la década de 1960, solo apareció en el libro editado por Darío Jaramillo, con un pequeño artículo sobre el “Modo de producción precolombino”.

  5. 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

    Directory of Open Access Journals (Sweden)

    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.

  6. PAH fluxes in the Laja Lake of south central Chile Andes over the last 50 years: Evidence from a dated sediment core

    International Nuclear Information System (INIS)

    Quiroz, Roberto; Popp, Peter; Urrutia, Roberto; Bauer, Coretta; Araneda, Alberto; Treutler, Hanns-Christian; Barra, Ricardo

    2005-01-01

    This paper reports the occurrence of polyaromatic hydrocarbons (PAHs) deposition inferred from a sediment core of an Andean lake in south central Chile. Sediments were carefully collected from one of the deepest section of the lake and sliced every 1 cm. The samples were analyzed for PAHs, 137 Cs, 210 Pb, organic carbon and grain-size. The stratigraphic chronology and the sedimentation rates were estimated using the sedimentary signature left by the 137 Cs and 210 Pb fallout as temporal markers. PAHs were quantified by HPLC-fluorescence detection (HPLC-Fluorescence). 15 priority EPA PAHs were analyzed in this study. Based on these results, PAH deposition over the last 50 years was estimated (a period characterized by an important intervention in the area). PAH concentration ranged from 226 to 620 ng g -1 d.w. The highest concentrations of PAHs were found in the core's bottom. The PAH profile is dominated by the presence of perylene indicating a natural source of PAH. In addition, two clear PAH deposition periods could be determined: the most recent with two-four rings PAHs, the older one with five-seven rings predomination. Determined fluxes where 71 to 972 μg m -2 year -1 , dominated by perylene deposition. PAH levels and fluxes are lower compared to the levels found in sediments from remote lakes in Europe and North America. It is concluded that the main source of PAHs into the Laja Lake sediments are of natural origin

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

    Directory of Open Access Journals (Sweden)

    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

  8. Clumped Isotope Thermometry Reveals Variations in Soil Carbonate Seasonal Biases Over >4 km of Relief in the Semi-Arid Andes of Central Chile

    Science.gov (United States)

    Burgener, L. K.; Huntington, K. W.; Hoke, G. D.; Schauer, A. J.; Ringham, M. C.; Latorre Hidalgo, C.; Díaz, F.

    2015-12-01

    The application of carbonate clumped isotope thermometry to soil carbonates has the potential to shed new light on questions regarding terrestrial paleoclimate. In order to better utilize this paleoclimate tool, outstanding questions regarding seasonal biases in soil carbonate formation and the relationship between soil carbonate formation temperatures (T(Δ47)) and surface temperatures must be resolved. We address these questions by comparing C, O, and clumped isotope data from Holocene/modern soil carbonates to modern meteorological data. The data were collected along a 170 km transect with >4 km of relief in central Chile (~30°S). Previous studies have suggested that soil carbonates should record a warm season bias and form in isotopic equilibrium with soil water and soil CO2. We identify two discrete climate zones separated by the local winter snow line (~3200 m). Below this boundary, precipitation falls as rain and soil carbonate T(Δ47) values at depths >40 cm resemble summer soil temperatures; at higher elevations, precipitation falls as snow and T(Δ47) values resemble mean annual soil temperatures. Soil carbonates from the highest sample site (4700 m), which is devoid of vegetation and located near perennial snow fields, yield anomalous δ18O, δ13C, and T(Δ47) values, indicative of kinetic isotope effects that we attribute to cryogenic carbonate formation. Our results suggest that soil carbonates from depths temperature and precipitation, and should not be used as paleotemperature proxies. These findings (1) highlight the role of soil moisture in modulating soil carbonate formation and the resulting T(Δ47) values, (2) underscore the importance of understanding past soil moisture conditions when attempting to reconstruct paleotemperatures using carbonate clumped isotope thermometry, and (3) suggest that soil carbonates from high elevation or high latitude sites may form under non-equilibrium conditions.

  9. Quechua II contraction in the Ayacucho intermontane basin: Evidence for rapid and episodic Neogene deformation in the Andes of central Perú

    Science.gov (United States)

    Wise, James M.; Noble, Donald C.; Zanetti, Kathleen A.; Spell, Terry L.

    2008-12-01

    In the Ayacucho basin of central Perú the regional Quechua II contractional deformation is bracketed by 40Ar/ 39Ar isotopic age determinations to a maximum duration of about 300,000 years, and probably less than 150,000 years, centered on 8.7 Ma. The strongly deformed Huanta Formation beneath the Quechua II angular unconformity was deposited during a period of extension that began before 9.05 ± 0.05 Ma. Deposition of a thick succession of alluvial fan deposits interbedded with flows of basaltic andesite in the Tingrayoc Member continued up to about 8.76 ± 0.05 Ma with the later part of the sedimentary record reflected by lacustrine deposits of the Mayocc Member. The upper limit on contractional deformation is constrained by an age of 8.64 ± 0.05 Ma on a unit of tuff near the base of the Puchcas volcanics, which in places was deposited upon near-vertical beds of the Huanta Formation. The Ayacucho Formation was deposited, locally unconformably, upon the Puchcas volcanics beginning slightly before 7.65 ± 0.10 Ma. Extended periods of neutral to tensional stress interrupted by rapid well-developed pulses of contractional deformation demonstrate the episodic behavior of Andean orogeny in Perú. The very short duration for the Quechua II event implies that driving forces for episodic deformation may be related to coupling along the orogen boundaries and strain accumulation and release mechanisms in the continental crust instead of much longer-term variations in the configuration of converging plates.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. U-series in zircon and 40Ar/39Ar geochronology reveal the most recent stage of a supervolcanic cycle in the Altiplano-Puna Volcanic Complex, Central Andes

    Science.gov (United States)

    Tierney, C.; de Silva, S. L.; Schmitt, A. K.; Jicha, B.; Singer, B. S.

    2010-12-01

    The ignimbrite flare up that produced the Altiplano-Puna Volcanic Complex of the Central Andes is characterized by episodic supervolcanism over a ~10 Ma time-span that climaxed about 4Ma. Since peak activity, the temporal and spatial record of volcanism suggests a waning of the system with only one other supervolcanic eruption at 2.6Ma. The most recent phase of volcanism from the APVC comprises a series of late Pleistocene domes that share a general petrochemical resemblance to the ignimbrites. New U-series data on zircons and high precision 40Ar/39Ar age determinations reveal that these effusive eruptions represent a temporally coherent magmatic episode. The five largest domes (Chao, Chillahuita, Chanka, Chascon-Runtu Jarita, and Tocopuri) have a combined volume >40 km3, and are distributed over an elliptical area of over 3000km2 centered at 22°S 68°W. They are crystal rich (>50%) dacites to rhyolites. New 40Ar/39Ar age determinations on biotite for the domes range range from 108±6 to 190±50 ka. However, 40Ar/39Ar ages from sanidine for some of the domes are more precise and span from 87±4 to 97±2 ka. We therefore interpret the eruption age of all these domes to be ~90 - 100 ka. This is consistent with SIMS U-series crystallization ages from the rims of 66 zircon crystals from four of the domes that reveal a fairly continuous spread of ages from ~90 ka to >300 ka with potentially common peaks in zircon ages at 100 ka and ~200 ka. U-Pb dating on the interiors of some of these zircon crystals indicates crystallization ages of up to 1.5 Ma. The common peaks of zircon crystallization between domes suggest that magma that fed these domes shared a larger regional source. Furthermore, the large volume of this potential source and the crystal-rich nature of the lava imply that this source was likely a large body of crystal-mush. The continuous nature of the zircon rim age population indicates that the residence time of this magma body was likely >200kyr. Potential

  16. 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

  17. 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

    Directory of Open Access Journals (Sweden)

    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.

  18. Mountain building processes in the Central Andes

    Science.gov (United States)

    Bloom, A. L.; Isacks, B. L.

    False color composite images of the Thematic Mapper (TM) bands 5, 4, and 2 were examined to make visual interpretations of geological features. The use of the roam mode of image display with the International Imaging Systems (IIS) System 600 image processing package running on the IIS Model 75 was very useful. Several areas in which good comparisons with ground data existed, were examined in detail. Parallel to the visual approach, image processing methods are being developed which allow the complete use of the seven TM bands. The data was organized into easily accessible files and a visual cataloging of the quads (quarter TM scenes) with preliminary registration with the best available charts for the region. The catalog has proved to be a valuable tool for the rapid scanning of quads for a specific investigation. Integration of the data into a complete approach to the problems of uplift, deformation, and magnetism in relation to the Nazca-South American plate interaction is at an initial stage.

  19. Rock glaciers, Central Andes, Argentina, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — Primary rock glaciers are fed by avalanche chutes. At the El Salto rock glacier, surveys have been undertaken in order to determine the creep rate. Between 1981 and...

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

    Directory of Open Access Journals (Sweden)

    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.

  1. Charles Darwin in the Andes

    Science.gov (United States)

    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…

  2. Evaluation of Little Ice Age cooling in Western Central Andes, suggested by paleoELAs, in contrast with global warming since late 19th century deduced from instrumental records

    Science.gov (United States)

    Ubeda, Jose; Palacios, David; Campos, Néstor; Giraldez, Claudia; García, Eduardo; Quiros, Tatiana

    2015-04-01

    This paper attempts to evaluate climate cooling (°C) during the glacial expansion phases using the product GTV•ΔELA, where GTV is the vertical air temperature gradient (°C/m) and ΔELA (m) the difference in level observed between the Equilibrium Line Altitude (ELA) reconstructions for current and past glaciers. With this aim the Area x Altitude Balance Ratio-(AABR) method was used to produce reconstructions of present ELAs (2002-2010) and paleoELAs corresponding to the last glacier advance phase. The reconstructions were produced in three study areas located along a N-S transect of the western cordillera in the Central Andes: the south-western sector of the Nevado Hualcán (9°S, 77°W; Giráldez 2011); the southern slope of the Cordillera Pariaqaqa (12°S, 76°W; Quirós, 2013) and the NW, NE, SE and SW quadrants of the Nevado Coropuna (16°S, 72°W; García 2013; Úbeda 2011; Campos, 2012). The three mountains exceed 6000 m altitude, their summit areas are covered by glaciers, and on their slopes there are existing well-conserved moraines deposited by the last advances near the present front of the ice masses. Although there are no absolute dates to confirm this hypothesis, it has been assumed that the last glacial advances occurred during the Little Ice Age (LIA), which the oxygen isotopes of the Nevado Huascarán (9°S, 77°W) date to the period 1500-1890. For the Hualcán and Pariaqaqa the mean global value of the Earth's GTV (6.5°C/km) was used, considered valid for the Tropics. On the Coropuna a GTV=8.4°C/km was used, based on high resolution sensors installed in situ since 2007 (Úbeda 2011). This gradient is approaching the upper limit of the dry adiabatic gradient (9.8°C/km), as the Coropuna region is more arid than the other case study areas. The climate cooling estimates deduced from the product GTV•ΔELA were compared with the global warming shown by the 1880-2012 series, ΔT=0.85°C, and 1850/1900-2003/2012, ΔT=0.78°C. The differences are

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

    Directory of Open Access Journals (Sweden)

    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

  4. 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.

  5. Estudio e implementación de metodologías para el análisis de hidrocarburos policíclicos aromáticos en zonas remotas frías de los andes peruanos

    OpenAIRE

    Maza Mejía, Ily Marilú

    2013-01-01

    Los compuestos orgánicos persistentes (COPs) como los pesticidas organoclorados, bifenilos policlorados (PCBs) y los hidrocarburos policíclicos aromáticos (PAHs) son sustancias de características hidrofóbicas, es decir, poco solubles en medios acuosos. Además, presentan gran resistencia química y biológica y, cuando son liberados al medio ambiente, tienden a ingresar a la cadena trófica y, en consecuencia, se magnifican y acumulan en diversos ecosistemas. Los materiales de características lip...

  6. Uso de marcadores moleculares microsatélites para determinar condición de homocigosis y heterocigosis en roedores producidos en el Bioterio de la Universidad de Los Andes, Venezuela

    OpenAIRE

    R. De Jesús; N. Rodríguez; W. Torres; Y. Moreno; J. O'Callaghan

    2011-01-01

    Los animales de laboratorio no consanguíneos, producidos en los bioterios para la investigación, tienen una alta probabilidad de incrementar su consanguinidad; así como los animales consanguíneos, tienen una alta probabilidad de alterar su homocigosis por la introgresión de genes que no corresponden al genoma de los mismos. El presente estudio tuvo como objetivo analizar marcadores moleculares microsatélites del adn extraído de ratones pertenecientes a las colonias de ratones BALB/C//BIOULA, ...

  7. 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...

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

    Directory of Open Access Journals (Sweden)

    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.

  9. 2011 Pacific Gas and Electric Diablo Canyon Power Plant (DCPP): Los Osos, CA Central Coast

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Diablo Canyon Power Plant (DCPP) LiDAR and Imagery datasets are comprised of three separate LiDAR surveys: Diablo Canyon (2010), Los Osos (2011), and San Simeon...

  10. Análisis genético molecular del Oso Andino ( Tremarctos ornatus en el norte de los andes (Venezuela, Colombia, Ecuador: Una visión global

    Directory of Open Access Journals (Sweden)

    M. Ruiz-García

    2001-07-01

    G10B, G10C y G10X. Un exhaustivo análisis genético poblacional permitió determinar los siguientes aspectos fundamentales: (1 No existencia de equilibrio Hardy-Weinberg ni en el conjunto global de muestras ni en el conjunto particular de muestras para cada uno de esos países, al utilizar los tests exactos con cadenas de Markov y con el método de Fisher.

  11. La geografía diferencial de los derechos: entre la regulación del trabajo forzado en los países coloniales y la disociación entre trabajadores e indígenas en los Andes (1920-1954)

    NARCIS (Netherlands)

    Barragàn, R.; Caruso, Laura; Stagnate, Andrés

    2017-01-01

    En los países andinos de Perú, Ecuador y Bolivia, los indígenas podían representar entre el 60 y hasta el 90% de su población; vivían relativamente autónomos en comunidades, pero cuando lo hacían en haciendas se encontraban sujetos a relaciones laborales descritas bajo diversos grados de

  12. Source apportionment of ambient particle number concentrations in central Los Angeles using positive matrix factorization (PMF

    Directory of Open Access Journals (Sweden)

    M. H. Sowlat

    2016-04-01

    Full Text Available In this study, the positive matrix factorization (PMF receptor model (version 5.0 was used to identify and quantify major sources contributing to particulate matter (PM number concentrations, using PM number size distributions in the range of 13 nm to 10 µm combined with several auxiliary variables, including black carbon (BC, elemental and organic carbon (EC/OC, PM mass concentrations, gaseous pollutants, meteorological, and traffic counts data, collected for about 9 months between August 2014 and 2015 in central Los Angeles, CA. Several parameters, including particle number and volume size distribution profiles, profiles of auxiliary variables, contributions of different factors in different seasons to the total number concentrations, diurnal variations of each of the resolved factors in the cold and warm phases, weekday/weekend analysis for each of the resolved factors, and correlation between auxiliary variables and the relative contribution of each of the resolved factors, were used to identify PM sources. A six-factor solution was identified as the optimum for the aforementioned input data. The resolved factors comprised nucleation, traffic 1, traffic 2 (with a larger mode diameter than traffic 1 factor, urban background aerosol, secondary aerosol, and soil/road dust. Traffic sources (1 and 2 were the major contributor to PM number concentrations, collectively making up to above 60 % (60.8–68.4 % of the total number concentrations during the study period. Their contribution was also significantly higher in the cold phase compared to the warm phase. Nucleation was another major factor significantly contributing to the total number concentrations (an overall contribution of 17 %, ranging from 11.7 to 24 %, with a larger contribution during the warm phase than in the cold phase. The other identified factors were urban background aerosol, secondary aerosol, and soil/road dust, with relative contributions of approximately 12

  13. Submarine earthquake rupture, active faulting and volcanism along the major Liquiñe-Ofqui Fault Zone and implications for seismic hazard assessment in the Patagonian Andes Ruptura sísmica submarina, tectónica y volcanismo activo a lo largo de la Falla Liquiñe-Ofqui e implicancias para el peligro sísmico en los Andes patagónicos

    Directory of Open Access Journals (Sweden)

    Gabriel Vargas

    2013-01-01

    Full Text Available The Liquiñe-Ofqui fault zone (LOFZ in the Patagonian Andes is an active major transpressional intra-arc fault system along which Quaternary faulting and volcanism develop. Subaerial and submarine geomorphologic and structural characterization of latest Pleistocene-Holocene faults and monogenetic volcanoes allows us to assess geological cartography of active faults and the kinematic model for recent tectonics during postglacial times, since 12,000 cal. years BP. This allows increasing the basic geological knowledge necessary for determining the seismic hazard associated with cortical structures in the Aysén region in southern Chile. Fault cartography and field observations suggest dominant dextral-reverse strike slip along north-south and locally NNW-striking faults, dextral-normal strike slip along NE to NNE- striking faults, and sinistral strike slip along east-west faults. This kinematics is consistent with regional SW-NE shortening in the context of a major transpressional fault zone. Holocene and even historic monogenetic and sub-aquatic volcanism occurred in this tectonic setting in a close spatial relationship and probably favored by the activity and local architecture of faults. Submarine fault scarps and deformed sediments observed at the bottom of the Aysén Fjord were associated with the destructive April 2007 Mw6.2 earthquake located along the LOFZ. Our observations show that this earthquake occurred along dextral 15-20 km long N-S structure named Punta Cola Fault (PCF. This fault system is located some kilometres to the east of the main N-S Río Cuervo Fault (RCF. Most of the epicentres of the seismic swarm during 2007 were located along or in between both structures. The study area is a transference zone between N-S regional branches of the LOFZ. The cartography of fault segments proposed here together with geophysical and geologic data suggest that large earthquakes Mw6.2-6.5 can be typically expected along most of the active

  14. ELABORACIÓN DE UN MODELO DE EVALUACIÓN PARA MEJORAR EL APRENDIZAJE EN LA MODALIDAD SEMIPRESENCIAL EN LA CARRERA DE DERECHO EN LA UNIVERSIDAD REGIONAL AUTÓNOMA DE LOS ANDES, ECUADOR

    OpenAIRE

    Ramos Sánchez, Rodrigo Estalin; Hernández Hernández, Mario; Vilchez Siccha, Arquímedes

    2017-01-01

    La investigación tuvo como propósito proponer un modelo de evaluación de carácter interactivo para la modalidad semipresencial que considere las dimensiones esenciales y la aplicación del mismo en un curso de derecho. El modelo propuesto incluye los lineamientos teóricos, metodológicos y operativos que relacionan los componentes del aprendizaje y la evaluación en la educación semipresencial. Utilizamos métodos teóricos: inductivo – deductivo, analítico – sintético e histórico, y los métodos e...

  15. Hydro-geochemical and isotopic fluid evolution of the Los Azufres caldera geothermal field, Central Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Partida, E [Centro de Geociencias, Campus Juriquilla-UNAM, Queretaro (Mexico); Viggiano-Guerra, J C [Subgerencia de Estudios C.F.E., Morelia. Michocan (Mexico); Perez, R J [Universidad de Calgary (Canada)], E-mail: egp@geociencias.unam.mx, E-mail: cesar.viggiano@cfe.gob.mx, E-mail: rene@geochemicalengineering.com

    2008-10-01

    Hydrothermal alteration at Los Azufres geothermal held is mostly propylitic showing progressive dehydration with depth, and temperature increase. The evolution of this system is inferred to be related to deep liquid water, boiling when ascending through fractures connected to the surface.

  16. Hydro-geochemical and isotopic fluid evolution of the Los Azufres caldera geothermal field, Central Mexico

    International Nuclear Information System (INIS)

    Gonzalez-Partida, E; Viggiano-Guerra, J C; Perez, R J

    2008-01-01

    Hydrothermal alteration at Los Azufres geothermal held is mostly propylitic showing progressive dehydration with depth, and temperature increase. The evolution of this system is inferred to be related to deep liquid water, boiling when ascending through fractures connected to the surface.

  17. 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

  18. La salud y los derechos humanos de las mujeres trabajadoras sexuales (Tema Central)

    OpenAIRE

    Chávez Naranjo, María José

    2014-01-01

    Los derechos humanos han significado una lucha histórica de las mujeres por alcanzar un lugar en la sociedad. El derecho a la salud de las mujeres ha sido reconocido a nivel nacional e internacional como un derecho humano fundamental, esencial para el desarrollo de otros derechos y garantizado desde el principio de igualdad y no discriminación. Sin embargo, al referirse a la salud de las mujeres trabajadoras sexuales se ha evidenciado que existen grandes esfuerzos por alcanzar su garantía, pr...

  19. Propuesta Metodológica para el Análisis de la Licuefacción de Suelos Asociada a Sismos Destrucutivos. Pre-Andes Centrales, Argentina (31º 30’ S y 68º 25’ O

    Directory of Open Access Journals (Sweden)

    Silvia Beatríz Palacios

    2017-01-01

    Full Text Available En este trabajo se evalúa la susceptibilidad a la ocurrencia de procesos de licuefacción de suelos asociados a sismos destructivos en el área ubicada al norte del río San Juan. Los terremotos de 1894, 1944, 1952 y 1977 provocaron licuefacción en el centro oeste de Argentina y particularmente en numerosos sitios de la provincia San Juan, resultando la zona norte del valle de Tulum, una de las más afectadas. Los registros históricos de procesos de licuefacción de suelos (PLS ocurridos durante los terremotos mencionados, evidencian grietas, volcanes de arena, cráteres y asentamientos diferenciales, los que ocasionaron importantes daños a las viviendas y al sector agro industrial de la región. En este estudio se efectuó un análisis de los factores principales que influyen en su ocurrencia, como también los efectos de la licuefacción. Se evaluaron y ponderaron los factores condicionantes tales como origen y granulometría del depósito, edad de los depósitos, profundidad del nivel freático y registros históricos entre otros. Del análisis de los factores resultó un mapa asociado a una tabla evaluativa. La influencia de los factores en la evaluación de la susceptibilidad se realizó mediante un proceso iterativo de superposición de mapas. Una vez conseguida la combinación óptima se obtuvo un mapa final de susceptibilidad a la licuefacción. La zonificación lograda se relacionó a un índice de susceptibilidad (IS, catalogado cualitativamente como Muy Alto, Alto, Moderado y Bajo. Los resultados obtenidos permiten concluir que el sector medio del abanico aluvial del río San Juan, donde se concentran los centros urbanos y la mayor actividad agropecuaria, es el sitio donde se exponen las condiciones de Muy Alta susceptibilidad, mientras que las de Alta susceptibilidad ocupan algunas zonas del sector medio-distal del abanico y las de Moderada a Baja se circunscriben al sector proximal del abanico.

  20. Entre la oralidad y la escritura: La importancia de la música, danza y canto de los Andes coloniales como espacios de significación, poder y mestizajes en contextos de colonialidad

    OpenAIRE

    Palominos Mandiola,Simón

    2014-01-01

    El presente artículo analiza el desarrollo de procesos de mestizaje cultural a partir de las expresiones musicales andinas del período colonial. Esto, con el fin de abrir la dicotomía "tradicional" que opone escritura y oralidad como las formas características de representación de la realidad propias de europeos y nativos (respectivamente). De esta forma, se espera poder comprender a los grupos sociales insertos en el espacio social colonial no como elementos estáticos sino que como identidad...

  1. Temporal variations in the diet of the exotic rainbow trout (Oncorhynchus mykiss in an Andean-Patagonian canopied stream Variación temporal en la dieta de la trucha exótica arco iris (Oncorhynchus mykiss en un arroyo forestado de los Andes patagónicos

    Directory of Open Access Journals (Sweden)

    LEONARDO M BURIA

    2009-03-01

    Full Text Available We examined seasonal and diel variation in prey species composition and biomass in the diet of the exotic rainbow trout Oncorhynchus mykiss (Walbaum, 1972. The study was carried out in the upper-forested sections of a low order stream in Andean-Patagonia. We studied the importance of functional feeding groups of aquatic invertebrates and the relative contribution of terrestrial and aquatic prey items in order to assess the pathways connecting terrestrial and aquatic ecosystems along a stream food web. Trout fed on approximately 40 invertebrate species and scrapers were consistently selected, suggesting their increased vulnerability to predation. However in terms of biomass, rainbow trout diet was mostly composed by shredders which emphasized the role of the allochthonous plant detritus pathway in food webs of forested small streams. Trout individuals fed more intensively in spring and summer and during daytime. Terrestrial items constituted a minor proportion of the diet implying that this component did not represent a significant subsidy for this fish population. As a consequence, the top-down effect on the aquatic community does not appear to be dampened since trout do not strongly preyed on terrestrial invertebrates.Se estudió la variación estacional y diaria en la composición y biomasa de las especies presa en la dieta de la exótica trucha arco iris Oncorhynchus mykiss (Walbaum, 1972 en la sección superior de un arroyo boscoso de bajo orden en los Andes patagónicos. Se analizó la importancia de los grupos funcionales alimentarios de invertebrados acuáticos y la contribución relativa de las presas de origen terrestre y acuático para evaluar las vías tróficas que conectan los ecosistemas acuático y terrestre circundantes. Las truchas consumieron aproximadamente unas 40 especies de invertebrados y los raspadores fueron consistentemente seleccionados, sugiriendo una alta vulnerabilidad a la depredación. Sin embargo en términos de

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

    Science.gov (United States)

    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.

  3. Hacia un nuevo clero en los Andes a finales del siglo XVIII: la ordenación A título de lengua en el Arzobispado de Lima

    Directory of Open Access Journals (Sweden)

    Lavallé, Bernard

    2011-08-01

    Full Text Available In the archbishopric of Lima, as well as in others, there is a significant change in the recruitment of secular clergy for parishes towards the end of the 18th century. The lenguaraces, those who know the indigenous language, are granted privilege by favoring that prerequisite above all others. This had notable consequences on their preparation, as well as the social and ethnic background of these priests, who were forced to work with a fragile status, with no possibility of relocation or promotion, all of which led to the appearance of a true lower clergy.En el arzobispado de Lima, como en otros, a finales del siglo XVIII se nota un cambio sustancial en el reclutamiento del clero secular para las doctrinas. Se privilegia entonces a los lenguaraces, conocedores de la lengua indígena, pasando ese requisito por encima de los demás. Eso tuvo consecuencias notables sobre la preparacion pero también el origen social y étnico de esos sacerdotes, obligados a trabajar con estatuto fragilizado, sin posibilidad de promocion ni cambio de destino, desembocando todo eso en la aparicion de un verdadero bajo clero.

  4. Mapeo de lineamientos a partir de un DEM (SRTM3: desarrollo y aplicaciones para el estudio de un área de los Andes Patagónicos Septentrionales

    Directory of Open Access Journals (Sweden)

    Ernesto Gallegos

    2008-12-01

    Full Text Available Este trabajo explora la utilidad del mapeo de lineamientos sobre mapas de relieve sombreado producidos con software para análisis de imágenes satelitales a partir de modelos de elevación digital (DEM de 3 segundos de resolución espacial. La zona de estudio se ubica entre 39°S y 39°30'S y entre 71°W y 71°30'W y se utilizaron tres mapas de relieve sombreado con luz incidente a 45º de la horizontal y azimuts de 120º, 240° y 360°. Tres operadores mapearon lineamientos de manera independiente en las diferentes imágenes con el resultado de nueve mapas independientes. Sólo los lineamientos mapeados en al menos 2 mapas de relieve sombreado por al menos dos operadores o por los tres operadores en al menos una de las imágenes fue considerado un lineamiento reproducible, de esta manera se obtuvieron 23 lineamientos. Las tendencias obtenidas son 55°, 106°, 140°, y 153°. Estos lineamientos fueron contrastados con lineamientos mapeados en una imagen GeoCoverT (Mosaico Ortorrectificado Comprimido de imágenes Landsat Enhanced Thematic Mapper, en la hoja geológica 1:200.000 (SEGEMAR y en mapas topográficos 1:50.000 (IGM. Algunos lineamientos claramente identificables a partir del DEM no se distinguieron en los mapas geológicos o topográficos ni en la imagen Landsat. Los autores consideran que existen ciertas ventajas del uso de modelos de elevación digital para el mapeo de lineamientos regionales: 1 Los usuarios pueden controlar el ángulo de incidencia de la luz y su azimut; 2 La escala de trabajo puede ser cambiada todas las veces que sea necesario; 3 A diferencia de las fotografías aéreas, los datos satelitales no tiene ningún tipo de deformación y no muestra influencia de rasgos antropogénicos o interferencia de la vegetación en la interpretación. Otra importante ventaja del DEM SRTM3 V2 y la imagen GeoCoverT usada en este caso es que se trata de datos de acceso gratuito y que cubren casi la totalidad de la Tierra. La

  5. 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

    Directory of Open Access Journals (Sweden)

    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.

  6. 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...

  7. Late Paleozoic to Triassic magmatism in the north-central High Andes, Chile: New insights from SHRIMP U-Pb geochronology and O-Hf isotopic signatures in zircon

    Science.gov (United States)

    Hernández González, Álvaro; Deckart, Katja; Fanning, Mark; Arriagada, César

    2014-05-01

    The Chilean High Andes (28o- 31oS) comprises a vast number of late Paleozoic - Triassic granitoids which give information about the last stages of Gondwana assemblage. Particularly, previous studies determined two tectonic configurations during this time: subduction related compressional setting (late Carboniferous - Late Permian) and non-subduction post-collisional extensional setting (Late Permian - Triassic), as the last stage of Gondwana assemblage. However, new O-Hf isotopic data along new U-Pb SHRIMP ages in zircon have shown that this model should be modified and updated to the new analytical data available. δ18O values indicate a strong change in the tectonic configuration approximately 270 Ma (earliest middle Permian) and thus, units can be divided into 2 mayor groups: late Carboniferous to earliest middle Permian and middle Permian to Triassic. The oldest group shows slightly low values of ɛHfi (ca. +1 to -4) with high δ18O (ca. >6.5 o/oo), indicating an elevated supracrustal component and the addition of less radiogenic continental-like material, which along significant residence time (TDM2: Mesoproterozoic) can be interpreted as magmas formed at depth in a subduction-related continental arc, and contaminated with supracrustal material and/or oceanic sediments transported through the subducted slab to the mantle-wedge. Subsequently, middle Permian - Triassic rocks show a wider range of ɛHfi values (ca. +3 to -3) with relatively low, mantle-like δ18O (ca. 4.5-6.5 o/oo), indicating a source of magmas without the addition of supracrustal material for some plutons, whilst for others, a slight input. The higher positive values of ɛHfi can be related to the influence of new juvenile material in the source of some magmas. This isotopic data can be interpreted as rocks formed as the result of melting of an old thinned mafic crust (with mantle-like δ18O values characteristic of this type of rocks) with limited addition of supracrustal material; in

  8. Las redes de drenaje de los rios Alberche y Guadarrama como indicadores estructurales del Sistema Central Espanol

    Directory of Open Access Journals (Sweden)

    Martín Escorza, C.

    2003-08-01

    Full Text Available The network of the Alberche and Guadarrama rivers, obtained by a semicuantitative method, shows that on the granitic and metamorphic rocks of the Spanish Central System exist circular alignments, until now detected by analysis of satellite image. Such alignments are located in the sub-geological system of the Sierra de Guadarrama, and they coexist with to already known rectilinear alignments. In the sub-westem system, Sierra de Gredos, are detected rectilinear alignments. The circular structures of Sierra de Guadarrarna would have a relationship to geological processes still unknown after the Hercynian Orogeny but before of the Oligocene.Utilizando una metodología semicuantitativa, las redes de drenaje de los ríos Alberche y Guadarrama ponen de manifiesto que existen alineaciones circulares sobre las rocas graníticas y metamórficas de la Cordillera Central, cuya presencia hasta ahora se había detectado por análisis de imagen de satélite. Tales alineaciones se sitúan en el subsistema geológico de la Sierra del Guadarrama, en donde coexisten con alineaciones rectas ya conocidas. En el subsistema occidental, la Sierra de Gredos, se detectan alineaciones rectas. Las estructuras circulares de la Sierra de Guadarrama tendrían su origen en relación con procesos geodinámicos todavía desconocidos, ocurridos con posterioridad a la Orogenia Hercínica, pero antes del Oligoceno.

  9. 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...

  10. 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...

  11. Hydro-geochemical and isotopic fluid evolution of the Los Azufres geothermal field, Central Mexico

    International Nuclear Information System (INIS)

    Gonzalez-Partida, E.; Carrillo-Chavez, A.; Levresse, G.; Tello-Hinojosa, E.; Venegas-Salgado, S.; Ramirez-Silva, G.; Pal-Verma, M.; Tritlla, J.; Camprubi, A.

    2005-01-01

    Hydrothermal alteration at Los Azufres geothermal field is mostly propylitic with a progressive dehydration with depth and temperature increase. Argillic and advanced argillic zones overlie the propylitic zone owing to the activity of gases in the system. The deepest fluid inclusions (proto-fluid) are liquid-rich with low salinity, with NaCl dominant fluid type and ice melting temperatures (T mi ) near zero (0 deg C), and salinities of 0.8 wt% NaCl equivalent. The homogenization temperature (T h ) = 325 ± 5 deg C. The boiling zone shows T h = ±300 deg C and apparent salinities between 1 and 4.9 wt% NaCl equivalent, implying a vaporization process and a very important participation of non-condensable gases (NCGs), mostly CO 2 . Positive clathrate melting temperatures (fusion) with T h = 150 deg C are observed in the upper part of the geothermal reservoir (from 0 to 700 m depth). These could well be the evidence of a high gas concentration. The current water produced at the geothermal wells is NaCl rich (geothermal brine) and is fully equilibrated with the host rock at temperatures between T = 300 and 340 deg C. The hot spring waters are acid-sulfate, indicating that they are derived from meteoric water heated by geothermal steam. The NCGs related to the steam dominant zone are composed mostly of CO 2 (80-98% of all the gases). The gases represent between 2 and 9 wt% of the total mass of the fluid of the reservoir. The authors interpret the evolution of this system as deep liquid water boiling when ascending through fractures connected to the surface. Boiling is caused by a drop of pressure, which favors an increase in the steam phase within the brine ascending towards the surface. During this ascent, the fluid becomes steam-dominant in the shallowest zone, and mixes with meteoric water in perched aquifers. Stable isotope compositions (δ 18 O-δD) of the geothermal brine indicate mixing between meteoric water and a minor magmatic component. The enrichment in δ 18

  12. 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.

  13. 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...

  14. 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 ...

  15. Hydro-geochemical and isotopic fluid evolution of the Los Azufres geothermal field, Central Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Partida, E. [Centro de Geociencias, UNAM, Campus Juriquilla, A.P. 15, Juriquilla, Qro., 76230 (Mexico)]. E-mail: egp@geociencias.unam.mx; Carrillo-Chavez, A. [Centro de Geociencias, UNAM, Campus Juriquilla, A.P. 15, Juriquilla, Qro., 76230 (Mexico); Levresse, G. [Centro de Geociencias, UNAM, Campus Juriquilla, A.P. 15, Juriquilla, Qro., 76230 (Mexico); Tello-Hinojosa, E. [Comision Federal de Electricidad, A.P. 31-7, C.P. 58090 Morelia, Mich. (Mexico); Venegas-Salgado, S. [Comision Federal de Electricidad, A.P. 31-7, C.P. 58090 Morelia, Mich. (Mexico); Ramirez-Silva, G. [Comision Federal de Electricidad, A.P. 31-7, C.P. 58090 Morelia, Mich. (Mexico); Pal-Verma, M. [Instituto de Investigaciones Electricas, A.P. 1-475, C.P. 62001 Cuernavaca, Morelos (Mexico); Tritlla, J. [Centro de Geociencias, UNAM, Campus Juriquilla, A.P. 15, Juriquilla, Qro., 76230 (Mexico); Camprubi, A. [Centro de Geociencias, UNAM, Campus Juriquilla, A.P. 15, Juriquilla, Qro., 76230 (Mexico)

    2005-01-01

    Hydrothermal alteration at Los Azufres geothermal field is mostly propylitic with a progressive dehydration with depth and temperature increase. Argillic and advanced argillic zones overlie the propylitic zone owing to the activity of gases in the system. The deepest fluid inclusions (proto-fluid) are liquid-rich with low salinity, with NaCl dominant fluid type and ice melting temperatures (T{sub mi}) near zero (0 deg C), and salinities of 0.8 wt% NaCl equivalent. The homogenization temperature (T{sub h}) = 325 {+-} 5 deg C. The boiling zone shows T{sub h} = {+-}300 deg C and apparent salinities between 1 and 4.9 wt% NaCl equivalent, implying a vaporization process and a very important participation of non-condensable gases (NCGs), mostly CO{sub 2}. Positive clathrate melting temperatures (fusion) with T{sub h} = 150 deg C are observed in the upper part of the geothermal reservoir (from 0 to 700 m depth). These could well be the evidence of a high gas concentration. The current water produced at the geothermal wells is NaCl rich (geothermal brine) and is fully equilibrated with the host rock at temperatures between T = 300 and 340 deg C. The hot spring waters are acid-sulfate, indicating that they are derived from meteoric water heated by geothermal steam. The NCGs related to the steam dominant zone are composed mostly of CO{sub 2} (80-98% of all the gases). The gases represent between 2 and 9 wt% of the total mass of the fluid of the reservoir. The authors interpret the evolution of this system as deep liquid water boiling when ascending through fractures connected to the surface. Boiling is caused by a drop of pressure, which favors an increase in the steam phase within the brine ascending towards the surface. During this ascent, the fluid becomes steam-dominant in the shallowest zone, and mixes with meteoric water in perched aquifers. Stable isotope compositions ({delta}{sup 18}O-{delta}D) of the geothermal brine indicate mixing between meteoric water and a

  16. Caracterización composicional de los depósitos arenosos actuales generados en el Sistema Central

    Directory of Open Access Journals (Sweden)

    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

  17. Medición del conocimiento de los tsunamis en escuelas del pacífico central costarricense

    Directory of Open Access Journals (Sweden)

    Fernández Arce, Mario

    2017-12-01

    Full Text Available A mediados de 2016 se investiga el conocimiento sobre tsunamis en cinco escuelas del Pacífico costarricense, a saber: la Escuela Central de Jacó, dos escuelas en Quepos, la escuela de Dominical y la Escuela Flor de Bahía en Uvita. La razón que impulsó a realizar este trabajo es que no se ha determinado el nivel de conocimiento del tema en la población de los centros educativos costeros. La investigación se realizó como un diagnóstico para iniciar un proceso de capacitación en manejo del riesgo en esas escuelas, cuyo fi n es aumentar la seguridad de la población estudiantil, prevenir desastres y reducir pérdidas humanas y materiales en caso de un eventual tsunami. Para lograr el objetivo se aplicó una encuesta de siete preguntas sobre el tema, con respuestas de escogencia única y luego se procesaron los datos manualmente. Se encontraron deficiencias de conocimiento, sin embargo, la población estudiada conoce ampliamente las reglas básicas para enfrentar un maremoto In the middle of 2016, we investigated the knowledge on tsunamis in five schools of the Costa Rican Pacific, whose names are: Escuela Central de Jacó, María Luisa Castro (Quepos, República de Corea (Quepos, Escuela de Dominical and Escuela Flor de Bahia (Uvita. We carried out this investigation because the subject is unknown in the in the population of coastal schools. The research was done to start a training process on risk management at these schools to increase the security of the students, prevent disasters and reduce deaths and material losses in the event of a possible tsunami. To achieve our objective we apply a seven questions poll about tsunamis, with single choice responses. The data were then processed manually. We found lack of knowledge in the students but they widely knows the basic rules to deal with a tsunami

  18. Prehnite-pumpellyite facies metamorphism in the Cenozoic Abanico Formation, Andes of central Chile (33°50'S): chemical and scale controls on mineral assemblages, reaction progress and the equilibrium state

    OpenAIRE

    Muñoz,Marcia; Aguirre,Luis; Vergara,Mario; Demant,Alain; Fuentes,Francisco; Fock,Andrés

    2010-01-01

    In the El Volcan and Rodeo de los Bueyes areas, Andean Principal Cordillera (east of Santiago; 33°50'S), an Upper Oligocene-Lower Miocene volcanic series belonging to the Abanico Formation (Late Eocene-Early Miocene) is exposed. The rock successions outcropping in both areas, ca. 3,300 m total thickness, have been affected by very low-grade, non-deformative metamorphism in the prehnite-pumpellyite facies. This is represented by the widespread development of secondary mineral assemblages compo...

  19. Prehnite-pumpellyite facies metamorphism in the Cenozoic Abanico Formation, Andes of central Chile (33°50'S): chemical and scale controls on mineral assemblages, reaction progress and the equilibrium state Metamorfismo de facies prehnita-pumpellyita en la Formación Abanico del Cenozoico, Andes centrales de Chile (33°50'S): controles químicos y de escala sobre las asociaciones minerales, el progreso de la reacción y el estado de equilibrio

    OpenAIRE

    Marcia Muñoz; Luis Aguirre; Mario Vergara; Alain Demant; Francisco Fuentes; Andrés Fock

    2010-01-01

    In the El Volcan and Rodeo de los Bueyes areas, Andean Principal Cordillera (east of Santiago; 33°50'S), an Upper Oligocene-Lower Miocene volcanic series belonging to the Abanico Formation (Late Eocene-Early Miocene) is exposed. The rock successions outcropping in both areas, ca. 3,300 m total thickness, have been affected by very low-grade, non-deformative metamorphism in the prehnite-pumpellyite facies. This is represented by the widespread development of secondary mineral assemblages compo...

  20. 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...

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

    Directory of Open Access Journals (Sweden)

    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

  2. Agro-Ecología en los Andes Peruanos

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

    áreas rurales que en las urbanas, y es aún peor en la región andina. ... forma sustentable de aumentar el rendimiento general agrícola, reducir la ... Internacional de Investigaciones para el Desarrollo (IDRC) de Canadá, que cuenta con el ...

  3. Prehnite-pumpellyite facies metamorphism in the Cenozoic Abanico Formation, Andes of central Chile (33°50'S: chemical and scale controls on mineral assemblages, reaction progress and the equilibrium state Metamorfismo de facies prehnita-pumpellyita en la Formación Abanico del Cenozoico, Andes centrales de Chile (33°50'S: controles químicos y de escala sobre las asociaciones minerales, el progreso de la reacción y el estado de equilibrio

    Directory of Open Access Journals (Sweden)

    Marcia Muñoz

    2010-01-01

    Full Text Available In the El Volcan and Rodeo de los Bueyes areas, Andean Principal Cordillera (east of Santiago; 33°50'S, an Upper Oligocene-Lower Miocene volcanic series belonging to the Abanico Formation (Late Eocene-Early Miocene is exposed. The rock successions outcropping in both areas, ca. 3,300 m total thickness, have been affected by very low-grade, non-deformative metamorphism in the prehnite-pumpellyite facies. This is represented by the widespread development of secondary mineral assemblages composed of epidote, mixed-layer chlorite-smectite, albite, quartz, white mica, and titanite. These mineral assemblages also contain pumpellyite, prehmte or prehnite+actinolite in a few samples. Chemical characteristics, such as low compositional variability of mixed-layer chlorite-smectite and actino-lite independent from the metadomain where these phases are hosted, along with a high proportion of chlorite layers in the former, suggest that these phases closely represent the whole rock effective bulk composition. On the contrary, pumpellyite compositions show a higher variability and a strong metadomain control evidencing its lower equilibration kinetics and leaving only those that grow in the rock matrix as the more closely representative of a whole rock effective bulk compositional control. Mineral assemblages from both areas show evidence of having been formed during the same metamorphic event where reactions have ocurred equivalently between them. However, local differences in chemical variables controlling this process are recognizable. A higher CO2 concentration in the fluids during the metamorphism in the El Volcán area than in the Rodeo de los Bueyes area is suggested by the scarce development of prehnite and the ubiquitous presence of calcite in the metamorphic assemblages of the former. Pressure and temperature of this metamorphic event have been roughly estimated to be lower than 2-3 kbar and 320°C, respectively.En las areas de El Volcán y Rodeo de

  4. 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

  5. Caracterización y propue stas de mejora de los sistemas de producción caprina de la costa central de Perú

    Directory of Open Access Journals (Sweden)

    José A. Sarria

    2014-01-01

    Full Text Available Perú tiene un importante sector caprino con rebaños de aptitud cárnica o mixta. Sin embargo, en los valles de la costa central hay una mayor tendencia a la orientación lechera, alimentando a los animales en bas e a rastrojos agrícolas. El objetivo de este estudio fue caracterizar las explotaciones de esta zona, pa ra lo cual se entrevistaron 60 ganaderos y se analizaron 39 variables. Se realizó un análisis multivariante seguid o de un ANOVA entre los cuatro grupos resultantes del mismo; obteniéndose dos dimensiones que explican el 69 .9 % de la varianza. Ocho variables mostraron diferencias significativas: (i educación del ganadero, los niveles primario y secundario predominaron respectivamente en los Grupos 2 y 3, P <0.05; (ii superficie de explotación, menos de 0.50 ha a excepción del Grupo 1, P <0.05; (iii modo de propiedad de la tierra, la propiedad privada fue menor en el Grupo 1, P <0.01; (iv importancia de las cabras, la producción caprina es la principal actividad del ganadero en los Grupos 3 y 4, P <0.001; (v número de caprinos, 97 y 80 respectivamente en los Grupos 1 y 4 y menos en el resto; P <0.001; (vii número de bovinos, 18 y 16 respectivamente en los Grupos 1 y 2, y menos en el resto, P <0.001; y (viii suministro de alimentos en la granja, no existiendo éste en los Grupos 1 y 4, P <0.01. Para tener continuidad y mejora, estos sistemas de producción caprina deberían reorganizarse de forma global, incrementar el tamaño de las explotaciones y tratar de comercializar productos diferen ciados.

  6. 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.

  7. Inventario y estrategias de mejora de los pastizales de los sistemas de producción de alpacas en la sierra central

    OpenAIRE

    Zarria Samanamud, Melody Rocio

    2015-01-01

    Universidad Nacional Agraria La Molina. Escuela de Posgrado. Maestría en Producción Animal Se diseñó un estudio para evaluar el estado del manejo y la condición de los pastizales de tres sistemas típicos de producción de alpacas de la región de Pasco: Cooperativas Comunales (CC), Granjas Comunales (GC) y Asociaciones de Productores (AP). El estudio comprendió la realización de inventarios de pastizales, el análisis de las percepciones de los productores sobre el estado y requerimientos de ...

  8. 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...

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

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

    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

  11. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  13. 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.

  14. 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

    Directory of Open Access Journals (Sweden)

    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.

  15. 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.

  16. La incorporación de los territorios nacionales en el proceso de consolidación del estado argentino. El caso del territorio de la Pampa Central

    Directory of Open Access Journals (Sweden)

    Marisa Moroni

    2005-01-01

    Full Text Available En la mayoría de los escritos de la élite letrada argentina del XIX, se identificó a la civilización como una manifestación de la identidad nacional, supuesto que las llevó a legitimar su función civilizadora y a impulsar el proceso de consolidación del Estado que requería la ocupación total del territorio, aún en manos de los indígenas a los que se responsabilizaba, junto con los caudillos, del fracaso de la unificación nacional. Desde las estructuras del poder estatal, se definió a los nuevos territorios como espacios vírgenes con infinitas posibilidades y ventajas económicas para explotar. Este argumento político atrajo pobladores -nacionales y extranjeros- que ocuparon y encaminaron la organización productiva de las futuras provincias. En este trabajo se realiza una aproximación al proceso de incorporación y posterior organización institucional de las tierras fronterizas incorporadas con la "Conquista al Desierto". En particular, se analiza la estructura político-administrativa del Territorio Nacional de la Pampa Central, constituido como tal en 1884, con el establecimiento de las primeras autoridades militares destinadas a fundar poblaciones y administrarlas políticamente.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Valoración socioambiental de los recursos naturales: el caso de los recursos minerales en la parte central de Baja California Sur, México

    OpenAIRE

    Luis F. Beltrán Morales; Víctor Sevilla Unda; Macià Blázquez Salom; Federico Salinas Zavala; Felipe García Rodrígez

    2005-01-01

    Se seleccionaron 15 localidades ubicadas en el radio de influencia de dos depósitos evaluados de fosfato, esto con la finalidad de aplicar el método de valoración contingente del recurso y su medio ambiente: el depósito de Tembabichi en el margen del Golfo de California y el depósito de Santo Domingo en la costa del Pacífico en Baja California Sur, México. Se encontró una disposición media a pagar por los habitantes del área de estudio de $29.77 pesos mensuales para colaborar con el medio amb...

  19. 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...

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

    Directory of Open Access Journals (Sweden)

    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.

  1. Efectos de las anomalías climáticas en la cobertura de nieve de los glaciares centrales del Perú

    Directory of Open Access Journals (Sweden)

    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.

  2. 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.

  3. Determinantes sociales de la exclusión a los servicios de salud y a medicamentos en tres países de América Central

    Directory of Open Access Journals (Sweden)

    Cecilia Acuña

    2014-02-01

    Full Text Available OBJETIVO: Examinar los determinantes sociales que afectan la conducta de la población en relación con la búsqueda y obtención de medicamentos, y su relación con la exclusión de los servicios de salud para datos agregados de tres países de América Central: Guatemala, Honduras y Nicaragua. MÉTODOS: Estudio observacional descriptivo de corte transversal, mediante la aplicación de una encuesta de hogares. La muestra del estudio se seleccionó de acuerdo al método de conglomerados. Los datos fueron analizados con el programa SPSS® V.17, utilizando estadística descriptiva y análisis bivariado, multivariado y por componentes principales (ACP. RESULTADOS: Aunque la mayoría de las personas pudo acceder a la atención en salud, la exclusión en salud (razón de probabilidades [RP] 4,10; intervalo de confianza de 95% [IC95%] fue el principal determinante de la falta de acceso a los medicamentos. Las características de la vivienda (RP 0,747, IC95%, la formalidad del empleo del jefe(a de hogar (RP 0,707, IC95% y las condiciones socioeconómicas del hogar (RP 0,462, IC95% fueron también importantes determinantes de la falta de acceso a los medicamentos. CONCLUSIONES: Los fenómenos de la falta de acceso a servicios de salud y a medicamentos no son independientes entre sí. Se corroboró que el sistema de salud, como determinante social intermediario de la salud, es un factor importante para la mejora del acceso a medicamentos. Las políticas públicas orientadas a alcanzar la cobertura universal deben contemplar esta relación para ser eficaces.

  4. 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...

  5. Relationships between mineralization and silicic volcanism in the central Andes

    Science.gov (United States)

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

    1983-01-01

    Existing models for the genesis of porphyry copper deposits indicate that they formed in granodioritic stocks located in the infrastructure of andesitic stratovolcanoes. It is noted that sites of porphyry-type subvolcanic tin mineralization in the Eastern Cordillera of Bolivia are distinguished by the absence of such andesitic structures. The surface expression of a typical subvolcanic porphyry tin deposit is thought to be an extrusive dome of quartz latite porphyry, sometimes related to a larger caldera structure. Evidence from the El Salvador porphyry copper deposit in the Eocene magmatic belt in Chile indicates that it too may be more closely related to a silicic volcanic structure than to an andesitic stratovolcano. The dome of La Soufriere, Guadeloupe is offered as a modern analog for the surface expression of subvolcanic mineralization processes, with the phreatic eruptions there indicating the formation of hydrothermal breccia bodies in depths. It is pointed out that the occurrence of mineralized porphyries, millions of years after caldera formation, does not necessarily indicate that tin intrusions and mineralization are not genetically related to the subcaldera pluton, but may be a consequence of the long thermal histories (1-10 million years) of the lowermost parts of large plutons.

  6. Production horticole saine et durable dans les Andes centrales ...

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

    La pratique de l'horticulture dans les vallées andines situées à mi-altitude requiert des quantités considérables de pesticides mutagènes très dangereux. Mais il s'agit d'une source de revenu supplémentaire pour les familles agricoles et d'une source d'approvisionnement en légumes frais pour les marchés des villes.

  7. Valoración socioambiental de los recursos naturales: el caso de los recursos minerales en la parte central de Baja California Sur, México

    Directory of Open Access Journals (Sweden)

    Luis F. Beltrán Morales

    2012-02-01

    Full Text Available Se seleccionaron 15 localidades ubicadas en el radio de influencia de dos depósitos evaluados de fosfato, esto con la finalidad de aplicar el método de valoración contingente del recurso y su medio ambiente: el depósito de Tembabichi en el margen del Golfo de California y el depósito de Santo Domingo en la costa del Pacífico en Baja California Sur, México. Se encontró una disposición media a pagar por los habitantes del área de estudio de $29.77 pesos mensuales para colaborar con el medio ambiente de su región. Hipotéticamente se daría una valoración contingente en el total del área de estudio de $227 859.58 pesos mensuales, es decir, $2 734 314.9 pesos anuales. Es una cantidad considerable de recursos para contribuir a mejoras en el medio ambiente por comunidades rurales con signos de marginación socioeconómica.

  8. Making Cultura Count inside and out of the Classroom: Public Art & Critical Pedagogy in South Central Los Angeles

    Science.gov (United States)

    Garcia, Luis-Genaro

    2012-01-01

    In this article, artist, educator, and activist Luis-Genaro Garcia describes the development and impact of the "May Day service learning project" on his advanced painting class in a high school in South Los Angeles. The project emerged from students' interests: their ideas, concerns for their community, socio-political consciousness, and…

  9. Los sistemas geotermales del Pirineo Central. II. Resultados de la aplicación de técnicas geotermométricas

    Directory of Open Access Journals (Sweden)

    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

  10. 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...

  11. Is there redundancy in bioengineering for molluscan assemblages on the rocky shores of central Chile? ¿Existe redundancia en la bioingeniería de los ensambles de moluscos de las costas rocosas de Chile central?

    Directory of Open Access Journals (Sweden)

    BRENDAN P KELAHER

    2007-06-01

    Full Text Available Bioengineers modify habitats via their own physical structures and substantially increase local diversity in marine ecosystems. On rocky shores, there are large overlaps in the composition of communities associated with bioengineers that form complex mat-like habitats. We investigated the potential for redundancy in habitat provision by these types of habitats by comparing diverse molluscan assemblages associated with Perumytilus purpuratus mussel beds and algal turfs of Corallina officinalis var. chilenis, Gelidium chilense and Gastroclonium cylindricum. At three times between September 2003 and January 2004, we sampled the molluscan assemblages associated with each bioengineer at similar tidal heights on two rocky shores on the coast of central Chile. Of the 31 molluscan species identified, 30 were found in Corallina and 19-22 were identified from the other habitats. The pool of species found associated with each bioengineer overlapped greatly, demonstrating the potential for redundancy in habitat provision and little habitat-specificity. However, multivariate and univariate analyses showed all bioengineers except Gastroclonium contained a unique molluscan assemblage for at least one time of sampling because of variation in frequency of occurrence, richness and total abundance. Recent studies have highlighted many anthropogenic and natural processes that directly influence the diversity and composition of bioengineering species on rocky shores. We demonstrate that the loss of any particular bioengineer would not substantially alter the overall pool of molluscan species on the rocky shores of Chile. The loss of any bioengineer except Gastroclonium would, however, result in decreased local biodiversity because the molluscan assemblages in Perumytilus, Corallina and Gelidium, each contained a significantly different community structure for at least one time of samplingEn los ecosistemas marinos los organismos bioingenieros modifican habitats a

  12. Antecedentes geobotánicos de una cuenca andina de Chile Central

    Directory of Open Access Journals (Sweden)

    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.

  13. Leptoglossus lonchoides Allen (Heteroptera, Coreidae), causente de la caida de los frutos de Bactris gasipaes (Palmae) en la Amazonia central

    OpenAIRE

    Couturier, Guy; Clement, C.R.; Viana Filho, P.

    1991-01-01

    #Leptoglossus lonchoïdes$ Allen (Heteroptera Coreidae) provoque la chute des fruits de #Bactris gasipaes$ HBK (Palmae) en Amazonie centrale. Les plantations de "pejibaye", #B.gasipaes$, un palmier neotropical domestiqué, souffrent d'importantes chutes de jeunes fruits en Amazonie centrale (Manaus, Amazonas, Brésil), dues en partie, peut-être principalement, à la punaise #L. lonchoïdes$. Dans cet article, on évalue l'importance économique des dégâts et on décrit l'insecte. (Résumé d'auteur)...

  14. 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.

  15. 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.

  16. 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...

  17. Estudio sobre el almacenamiento de agua helada en los sistemas de climatización centralizados; Study about cooling water storage in centralized air conditioning system

    Directory of Open Access Journals (Sweden)

    Mario Espín Pérez

    2015-04-01

    Full Text Available El desarrollo de este artículo se basa en el estudio del almacenamiento de agua helada en los sistemas de climatización. Para desplazar el consumo eléctrico fuera del horario pico, como herramienta para pretender  incrementar  la eficiencia energética y disminuir el costo de la energía eléctrica en los hoteles con clima tropical. Para ello se procede a la estimación del perfil de carga térmica del hotel Jagua mediante el software TRNSYS, diseño y comprobación del sistema de almacenamiento de agua helada incorporado a las condiciones actuales de la instalación mediante modelos matemáticos que describen su funcionamiento. El objetivo es, evaluar e ilustrar los posibles efectos cuantitativos y cualitativos del almacenamiento de agua helada en el sistema de clima centralizado de la edificación. El trabajo que se presenta se enmarca en los esfuerzos para desarrollar el uso de tecnologías sustentables y la evaluación de sistemas industriales asistidos por computadora en Cuba. The development of this paper is based on the study of cold water storage in air conditioning systems. To offset power consumption off-peak, as a tool to increase energy efficiency claim and reduce the cost of electricity in tropical hotels. To do this we proceed to estimate the thermal load profile Jagua by TRNSYS software, system design and testing of chilled water storage built into the current conditions of the system using mathematical models to describe their operation. The objective is to evaluate and illustrate the quantitative and qualitative effects of cold water storage in the building centralized climate system. The work presented is part of the efforts to develop the use of sustainable technologies and evaluation of computer-aided industrial systems in Cuba.

  18. 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).

  19. 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

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

    Science.gov (United States)

    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

  1. The structural architecture of the Los Humeros volcanic complex and geothermal field, Trans-Mexican Volcanic Belt, Central Mexico

    Science.gov (United States)

    Norini, Gianluca; Groppelli, Gianluca; Sulpizio, Roberto; Carrasco Núñez, Gerardo; Davila Harris, Pablo

    2014-05-01

    The development of geothermal energy in Mexico is a very important goal, given the presence of a large heat anomaly, associated with the Trans-Mexican Volcanic Belt, the renewability of the resource and the low environmental impact. The Quaternary Los Humeros volcanic complex is an important geothermal target, whose evolution involved at least two caldera events, that alternated with other explosive and effusive activity. The first caldera forming event was the 460 ka eruption that produced the Xaltipan ignimbrite and formed a 15-20 km wide caldera. The second collapse event occurred 100 ka with the formation of the Zaragoza ignimbrite and a nested 8-10 km wide caldera. The whole volcano structure, the style of the collapses and the exact location of the calderas scarps and ring faults are still a matter of debate. The Los Humeros volcano hosts the productive Los Humeros Geothermal Field, with an installed capacity of 40 MW and additional 75 MW power plants under construction. Recent models of the geothermal reservoir predict the existence of at least two reservoirs in the geothermal system, separated by impermeable rock units. Hydraulic connectivity and hydrothermal fluids circulation occurs through faults and fractures, allowing deep steam to ascend while condensate flows descend. As a consequence, the plans for the exploration and exploitation of the geothermal reservoir have been based on the identification of the main channels for the circulation of hydrothermal fluids, constituted by faults, so that the full comprehension of the structural architecture of the caldera is crucial to improve the efficiency and minimize the costs of the geothermal field operation. In this study, we present an analysis of the Los Humeros volcanic complex focused on the Quaternary tectonic and volcanotectonics features, like fault scarps and aligned/elongated monogenetic volcanic centres. Morphostructural analysis and field mapping reveal the geometry, kinematics and dynamics of

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. The Performance of Major Plant Items at Calder Hall; Fonctionnement des elements principaux de la centrale de Calder Hall; Kharakteristika osnovnykh uzlov ustanovki v Kolder-Kholle; Rendimiento de los principales elementos de la central de Calder Hall

    Energy Technology Data Exchange (ETDEWEB)

    Desbruslais, E. L. [United Kingdom Atomic Energy Authority, Seascale, Cumberland (United Kingdom)

    1963-10-15

    dans les canaux a combustible, et de pinces speciales, a permis de reduire les temps de dechargement. On n'a enregistre que des defaillances mineures dans les mecanismes complexes de commande des barres de reglage et le materiel de controle connexe. Dans toute la mesure du possible le controle de l'usine doit etre centralise et les principaux centres de controle ainsi que les elements importants de l'usine doivent etre proteges de tout dommage accidentel pouvant provenir de l'exterieur. Pour la generatrice diesel de secours, il ne semble pas necessaire de prevoir le demarrage automatique et des circuits doubles, mais une centralisation ne serait pas inutile. (author) [Spanish] Desde hace mas de seis afios, Calder Hall viene funcionando como central para la carga basica, habiendo sufrido avenas similares a las que se registran en las centrales clasicas de electricidad. Todas las fallas se han producido en la parte clasica de la central y ninguna en los reactores propiamente dichos. La experiencia ha demostrado que, desde el punto de vista de la seguridad de los reactores, estos mismos y los principales elementos de la central, asi como las conexiones con la red, se han de considerar en conjunto. No se ha observado ningun cambio importante que sugiera que el recipiente de presion del reactor o el moderador de grafito limitaran la vida util de la central. La distribucion de temperatura alrededor de los conductos de salida de gas es asimetrica, lo cual limita actualmente la potencia del reactor. Se ha recomendado montar mas pares termoelectricos, asi como instrumentos para medir deformaciones y dispositivos que permitan observar visualmente zonas de tension y temperaturas elevadas. Durante el funcionamiento normal, no se emplean ya los desecadores Humidrier y gracias a ello se ha logrado un ligero aumento de la potencia del reactor. Se formulan algunas recomendaciones respecto de la frecuencia de las inspecciones de los intercambiadores de calor, de los principales

  5. El valor de la opinión en los noticieros televisivos chilenos de hoy el caso de 24 horas central de TVN

    Directory of Open Access Journals (Sweden)

    Jimena Maiz Sáenz-Villarreal

    2014-12-01

    Full Text Available Con la cultura de masas y como efecto de la búsqueda de consenso propia de la democracia, la opinión, entendida como juicio de valor, se ha incorporado en los noticieros televisivos como medio de legitimación para el líder que la emite y como forma de identificación para el receptor que se sienta representado por ella. Por ello, su intención es generar un acercamiento con el destinatario, tratando de impactar, al mismo tiempo, su inteligencia y sus emociones, para orientarlo en algún sentido a través de opiniones propiamente tales, expresión de sentimientos y apelaciones. El presente trabajo busca demostrar este planteamiento mediante el análisis semiótico del noticiario 24 horas Central de TVN, utilizando para ello el paradigma de Charles Morris.

  6. Rentabilidad de la gestión del mantenimiento en los centrales azucareros cubanos. // Profitability of maintenance management in Cuban sugar cane factories.

    Directory of Open Access Journals (Sweden)

    C. Batista Rodríguez

    2001-10-01

    Full Text Available Para evaluar de forma acertada la eficiencia de la gestión de mantenimiento en un central azucarero y a su personaldirectivo es necesario disponer de indicadores cuantitativos que reflejen los resultados y la evolución integral del trabajotécnico-organizativo y económico de la actividad. Actualmente existen gran cantidad de indicadores, pero se adolece de lano existencia de un indicador generalizador de la eficiencia de la gestión del mantenimiento, por lo cual es difícil valorarcorrectamente los resultados y la evolución integral de la actividad.En este trabajo se muestra la posibilidad de evaluar de forma integral la eficiencia de la gestión del mantenimiento en loscentrales azucareros cubanos, con el calculo del indicador Rentabilidad de la gestión del mantenimiento (Rgm.Palabras claves: Rentabilidad, gestión de mantenimiento, centrales azucareros, indicador de rentabilid__________________________________________________________________AbstractIn order to evaluate in a proper manner the efficiency of maintenance management in sugar cane factories and its directivepersonnel, it is necessary to have quantitative indicators that reflect the results and integral evolution of the technicalorganizationaland economic work of the activity. At the present a great amount of indicators exists, but it is sympathizedfrom the non-existence of a generalizing indicator of the maintenance management efficiency, thus it is difficult tocorrectly validate the results and integral evolution of the activity. In this paper is expose the possibility of integralevaluation of the maintenance management efficiency in Cuban sugar cane factories, with the computation of the indicatorof maintenance management profitability (Rgm.Key words: Profitability, maintenance management, sugar cane factories, profitability indicator.

  7. The economic impact of Los Alamos National Laboratory on north-central New Mexico and the state of New Mexico fiscal year 1997

    International Nuclear Information System (INIS)

    Lansford, R.R.; Nielsen, T.G.; Schultz, J.; Adcock, L.D.; Gentry, L.M.

    1998-01-01

    Los Alamos National Laboratory (LANL) is a multidisciplinary, multiprogram laboratory with a mission to enhance national military and economic security through science and technology. Its mission is to reduce the nuclear danger through stewardship of the nation's nuclear stockpile and through its nonproliferation and verification activities. An important secondary mission is to promote US industrial competitiveness by working with US companies in technology transfer and technology development partnerships. Los Alamos is involved in partnerships and collaborations with other federal agencies, with industry (including New Mexico businesses), and with universities worldwide. For this report, the reference period is FY 1997 (October 1, 1996, through September 30, 1997) and includes two major impact analysis: the impact of LANL activities on north-central New Mexico and the economic impacts of LANL on the state of New Mexico. Total impact represents both direct and indirect respending by business, including induced effects (respending by households). The standard multipliers used in determining impacts result from the inter-industry, input-output models developed for the three-county region and the state of New Mexico. 5 figs., 12 tabs

  8. Rentabilidad de la gestión del mantenimiento en los centrales azucareros cubanos. // Maintenance management rentability in Cuban sugar mills.

    Directory of Open Access Journals (Sweden)

    C. Batista Rodríguez

    2003-01-01

    Full Text Available Para evaluar de forma acertada la eficiencia de la gestión de mantenimiento en un central azucarero y a su personaldirectivo es necesario disponer de indicadores cuantitativos que reflejen los resultados y la evolución integral del trabajotécnico-organizativo y económico de la actividad. Actualmente existen gran cantidad de indicadores, pero se adolece de lano existencia de un indicador generalizador de la eficiencia de la gestión del mantenimiento, por lo cual es difícil valorarcorrectamente los resultados y la evolución integral de la actividad.En este trabajo se muestra la posibilidad de evaluar de forma integral la eficiencia de la gestión del mantenimiento en loscentrales azucareros cubanos, con el cálculo del indicador Rentabilidad de la gestión del mantenimiento (Rgm.Palabras claves: Gestión de mantenimiento, rentabilidad, eficiencia.________________________________________________________________________________Abstract:In order to properly evaluate the sugar mills maintenance management rentability and its directive personnel there is a needfor cuantitative indicators that reflect results and integral activity evolution. Actually there is a great deal of such indicators,but there is a lack of management maintenance generalizator indicators, making correct results valoration and integralactivity evolution a difficult task. In this paper is exposed the possible evaluation of maintenance management in Cubansugar mills with the Rentability management indicator (Rgm.Key words: Maintenance manegement, rentability, efficiency.

  9. The economic impact of Los Alamos National Laboratory on north-central New Mexico and the state of New Mexico fiscal year 1998; TOPICAL

    International Nuclear Information System (INIS)

    Lansford, R.R.; Adcock, L.D.; Gentry, L.M.; Ben-David, S.

    1999-01-01

    Los Alamos National Laboratory (LANL) is a multidisciplinary, multiprogram laboratory with a mission to enhance national military and economic security through science and technology. Its mission is to reduce the nuclear danger through stewardship of the nation's nuclear stockpile and through its nonproliferation and verification activities. An important secondary mission is to promote US industrial competitiveness by working with US companies in technology transfer and technology development partnerships. Los Alamos is involved in partnerships and collaborations with other federal agencies, with industry (including New Mexico businesses), and with universities worldwide. For this report, the reference period is FY 1998 (October 1, 1997, through September 30, 1998). It includes two major impact analysis: the impact of LANL activities on north-central New Mexico and the economic impacts of LANL on the state of New Mexico. Total impact represents both direct and indirect responding by business, including induced effects (responding by households). The standard multipliers used in determining impacts result from the inter-industry, input-output models developed for the three-county region and the state of New Mexico

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

    Directory of Open Access Journals (Sweden)

    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.

  11. 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

  12. Los efectos geoecológicos del cambio global en el Pirineo Central español: una revisión a distintas escalas espaciales y temporales

    Directory of Open Access Journals (Sweden)

    García-Ruiz, José M.

    2015-12-01

    evapotranspiration; (ii the spatial shrinkage of sediment source areas; (iii the increasing uncoupled geomorphic dynamics between hillslopes and channels; (iv the decreasing importance of snow accumulation and snowmelt processes in the fluvial regime of the Pyrenean rivers, with earlier onset of the high spring discharges; (v the changes in reservoir hydrological dynamics and the need for new management policies; and (vi the increasing scouring processes that affect most of the Pyrenean rivers. The studies carried out on Global Change and its consequences in the Central Pyrenees confirm the extreme complexity of interactions occurring in the natural systems, and the quick response of plant cover, runoff generation and soil erosion as a consequence of climatic and land use changes.Se revisan los efectos de la evolución del clima y los cambios de uso del suelo / cubierta vegetal en el Pirineo Central español a diferentes escalas espaciales y temporales. Los estudios paleoclimáticos, basados en análisis multiproxy de sedimentos lacustres, glaciares, espeleotémicos y registros dendrológicos, entre otros, han demostrado la ocurrencia de importantes fluctuaciones climáticas durante la deglaciación de finales del Pleistoceno Superior y durante el Holoceno, afectando a la distribución de la vegetación, la generación de escorrentía, la frecuencia de avenidas y las formas de organización del espacio por parte de las sociedades humanas, en particular durante el evento 8.2, la Edad del Bronce, la Anomalía Climática Medieval y la Pequeña Edad del Hielo. El estudio del impacto de las actividades humanas sobre la dinámica del paisaje en el último siglo y medio ha revelado cambios espectaculares en la estructura y distribución de la vegetación, tanto en el piso montano como en el subalpino y, consecuentemente, cambios en la generación de escorrentía, la intensidad de la erosión del suelo y las fuentes de sedimento, cualquiera que sea la escala espacial a la que se contempla

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

    Directory of Open Access Journals (Sweden)

    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.

  14. Factores de riesgo asociados con la hipertensión arterial en los trabajadores de la oficina central del MINBAS

    Directory of Open Access Journals (Sweden)

    Lourdes Rodríguez Domínguez

    1997-10-01

    Full Text Available Se realizó un estudio descriptivo del total de hipertensos que laboran en el Ministerio de la Industria Básica, en el período de enero a diciembre de 1995 con el objetivo de identificar los factores de riesgo que favorezcan la aparición de la hipertensión arterial y sus diferencias según el sexo. El grupo de edad más afectado fue el comprendido entre 50 y 59 años, con predominio del sexo masculino. La historia familiar de hipertensión arterial (96,5 %, la cardiopatía isquémica (32,60 % y la hipercolesterolemia (30,60 %, estuvo presente aunque su relación con el sexo no fue significativa. La hipertensión arterial se vio relacionada de forma significativa con la obesidad en el sexo femenino y con el hábito de fumar, el sedentarismo y la categoría ocupacional de dirigente en el sexo masculino.A descriptive study of the total number of hypertensives working at the Ministry of the Basic Industry from January to December, 1995, was conducted aimed at identifying those risk factors favoring the appearance of arterial hypertension and their differences according to sex. The age group 50-59 was the most affected and there was a predominance of the male sex. The family history of arterial hypertension (96.5 %, ischemic cardiopathy (32.60 % and hypercholesterolemia (30.60 % were present eventhough their relationship with sex was no significant. Arterial hypertension was markedly connected with obesity in the female sex and with the smoking habit, sedentarism, and the leader occupational category in the male sex.

  15. Environmental evaluation of fluoride in drinking water at "Los Altos de Jalisco," in the central Mexico region.

    Science.gov (United States)

    Hurtado, Roberto; Gardea-Torresdey, Jorge

    Naturally occurring fluoride has been detected and quantified in drinking water in several cities of the "Los Altos de Jalisco" (LAJ) region. LAJ is located in the northeastern part of the state of Jalisco-Mexico, covering an area of 16,410 km2 with a population of 696,318 in 20 municipalities. Drinking water comes mainly from groundwater aquifers, located in the Trans-Mexican Volcanic Belt, which is a volcanic region characterized by hydrothermal activity. Results indicated that water supply from 42% of the municipalities had a fluoride concentration over the Mexican standards of 1.5 mg/L. It is important to notice that there are three cities, Lagos de Moreno (1.66-5.88 mg/L F(-)), Teocaltiche (3.82-18.58 mg/L F(-)), and Encarnación de Díaz (2.58-4.40 mg/L F(-)) where all water samples resulted in fluoride concentration over the maximum contaminant level. The total population from these three cities is over 122,000 inhabitants. Another important city with high levels of fluoride in the water supply was Tepatitlán de Morelos (2 wells with 6.54 and 13.47 mg/L F(-)). In addition to water supply, 30 samples of brand-name bottled water were tested. Surprisingly, 8 samples (27%) demonstrated fluoride level over the standards, mainly Agua de Lagos with 5.27 mg/L. Fluoridated table salt (200-300 mg/kg F(-)) is another important source of fluoride. A large number of people living in the region, mainly school children, might be under adverse health risk because they are consuming contaminated drinking water. It is well known that long-term exposure to water with high levels of fluoride produces severe health problems.

  16. 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.

  17. 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

  18. El uso de la modelización para mejorar la calidad ambiental y la gestión integral de los recursos hídricos en dos cuencas fluviales de la región central de Cuba

    OpenAIRE

    Alarcón Acá, Samuel; Jiménez-Gavilán, Pablo

    2017-01-01

    La gestión de los recursos hídricos presenta cada vez mayores dificultades debido a la presión siempre creciente sobre los recursos disponibles, el alto grado de regulación de las fuentes convencionales y las pocas posibilidades de incrementar las reservas sin recurrir a fuentes alternativas, especialmente en territorios donde los periodos de escasez son recurrentes. Este es el escenario que presentan las dos cuencas fluviales objeto de estudio en este trabajo, en la región central de Cuba...

  19. 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...

  20. Propuesta de implementación de una guía de procedimientos para mejorar la eficiencia en los procesos de la Central de Esterilización del Hospital "Dr. Teodoro Maldonado Carbo" de la ciudad de Guayaquil.

    OpenAIRE

    Payez Freire, Eva Cristina

    2015-01-01

    La presente investigación se desarrolló en la central de esterilización del Hospital Teodoro Maldonado Carbo de la ciudad de Guayaquil, perteneciente al Instituto Ecuatoriano de Seguridad Social, con la finalidad de evaluar el nivel de aplicación de los procedimientos obligatorios de esterilización y su relación con el nivel de eficiencia en los resultados obtenidos. Para el logro de los objetivos planteados se desarrolló una investigación de campo aplicando encuestas y entrevistas al...

  1. Elaboración de los procedimientos técnico administrativos de enfermería en base a estándares de calidad en la Central de Esterilización del Hospital Eugenio Espejo

    OpenAIRE

    Chumbi Quito, Ruth Emperatriz

    2016-01-01

    En la actualidad resulta indispensable mantener la disciplina laboral en las instituciones como método de lograr el cumplimiento de los objetivos propuestos, de allí la necesidad de realizar el correcto manejo de los recursos materiales, tecnológicos, económicos y en primer lugar el recurso humano como formador de bienes. El presente trabajo posee el objetivo de elaborar los procedimientos técnico administrativos de enfermería en base a estándares de calidad en la Central de Esterilización de...

  2. Estado de conservación de los peces de la familia Goodeidae (Cyprinodontiformes en la mesa central de México

    Directory of Open Access Journals (Sweden)

    Marina Y De la Vega-Salazar

    2006-03-01

    Full Text Available Se estableció el estado de conservación y se identificaron los riesgos que presentan los peces de la familia Goodeidae en la Mesa Central de México. Para ello se evaluó la disminución en el número de localidades y el área de distribución, y se incorporó una descripción limnológica en 53 localidades. Esta evaluación incluyó una comparación de las colecciones actuales con registros hist��ricos de la distribución de la familia. Un análisis de componentes principales de las variables limnológicas indicó que la mayoría de las especies de goodeidos habitan localidades caracterizadas por tener poca degradación ambiental, y sólo pocas especies parecen tener elevada tolerancia a dicho estado de contaminación. Los resultados de la disminución histórica de localidades y del área de distribución sugieren que el estado de conservación de las especies (de acuerdo con los criterios de la IUCN es el siguiente: una especie está extinta (Allotoca catarinae, una especie está extinta en la naturaleza (Skiffia francesae, ya que existen ejemplares en cautiverio, ocho están en peligro crítico (Allotoca goslinei, Allotoca regalis, Allotoca zacapuensis, Allodontichthys hubbsi, Ameca splendens, Characodon audax, Hubbsina turneri y Zoogoneticus tequila, once están en peligro, ocho se consideran como vulnerables, cuatro se pueden considerar en riesgo próximo y sólo dos parecen no enfrentar ningún riesgo. En conclusión, la pérdida de hábitat, la introducción de especies exóticas de peces, el ámbito geográfico restringido y la especialización ecológica de las especies son los principales factores de riesgo para las especies estudiadas de la familia Goodeidae. La supervivencia de este grupo requiere acciones para su conservación.Conservation status of Goodeidae familiy fishes (Cyprinodontiformes from the Mexican Central Plateau. To establish the conservation status and threats for Goodeidae fishes in the high plateau of Mexico

  3. Competencias informacionales de los estudiantes de la escuela de bibliotecología de la Universidad Central de Venezuela - Information skills of students the school of library science at library science at Universidad Central de Venezuela

    Directory of Open Access Journals (Sweden)

    José Jesus López Salazar

    2016-12-01

    Full Text Available El presente trabajo examina las competencias informacionales de los estudiantes de la Escuela de Bibliotecología de la Universidad Central de Venezuela. Para ello se aplicó un cuestionario de 25 presuntas abiertas, cerradas y mixtas a 213 estudiantes cursantes de la asignatura obligatoria Seminario de tesis dictada durante los periodos lectivos 2014-2, 2015-1 y 2015-2 como parte de una evaluación diagnóstico que buscó establecer el conocimiento y las habilidades que deben poseer para iniciar una investigación bibliotecológica. Se utilizaron cuatro parámetros para medir el reconocimiento de la necesidad de conseguir información, localizar información y acceder a ella, establecer estrategias para localizar la información, distinguir entre distintas formas de cubrir la necesidad, comparar y evaluar la información, organizar, aplicar y comunicar la información. Las competencias informacionales de los estudiantes de la Escuela de Bibliotecología hacia la investigación puede ser valorada como moderada o mediana que requiere de estrategias de enseñanza aprendizaje para desarrollar aptitudes para localizar la información, comparar y evaluar la información, organizar, aplicar y comunicar la información de manera ética. Abstract This paper examines the information skills of Central University of Venezuela´s Library Sciences School students. For this reason, a questionnaire of 25 open and closed mixed questions was applied to 213 thesis seminars students during school periods 2014-2, 2015-1 and 2015-2 as part of a diagnostic evaluation that sought to establish the knowledge and skills that should be developed to initiate an investigation in the library science field. Four parameters were used to measure the recognition of the information needs, find the information and access to it, establish the strategies to locate information, distinguish between different ways of meeting the need, compare and evaluate information, organize

  4. Diversification of clearwing butterflies with the rise of the Andes.

    Science.gov (United States)

    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.

  5. 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

  6. 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.

  7. El desarrollo de los cibermedios venezolanos

    Directory of Open Access Journals (Sweden)

    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.

  8. 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

  9. La centralidad en las comunicaciones y la influencia percibida en los pequeños grupos The communication centrality and the perceived influence in small groups

    Directory of Open Access Journals (Sweden)

    Nancy Noemi Terroni

    2003-06-01

    Full Text Available Este trabajo reporta los resultados de medidas del análisis de redes en la comunicación de pequeños grupos que resuelven una tarea de recuperación de memoria y su asociación con la influencia percibida. El reactivo empleado es una historia y los 65 participantes, alumnos de la Universidad Nacional de Mar del Plata, debieron reconstruir la misma primero en forma individual, luego grupal colaborativa y nuevamente en forma individual. Se registraron las interacciones grupales con comunicación cara a cara y mediada por computadora; se analizaron las medidas de prominencia, la centralidad y el prestigio de la comunicación y el tipo de alocución, orientado a la gestión grupal o hacia la tarea. Se observaron asociaciones significativas entre las medidas reticulares y la influencia percibida para ambos medios de comunicación y se hallaron diferencias en la comunicación de gestión grupal. Se discuten estos resultados con relación a las restricciones que imponen los canales de comunicación mediados.This work reports reticular measures of the social network analysis in the communication of small groups while solving a recall memory task and their association with the perceived influence. The task used is a story and the 65 subjects, students at the Mar del Plata University had to reconstruct the story, first individually, then in collaborative groups and again individually. The subjects’ interactions in face to face and computer mediated communication groups were recorded; the prominence measures, the centrality and the prestige of the communication and the type of speech were analyzed, oriented to the group management or towards the task (conceptual. Significant associations between the reticular measures and the perceived influence were observed, for both media, and differences in the group management communications were found. These results in relation to the restrictions of the communication mediated channels are discussed.

  10. Determinantes del acceso a los productos financieros en los hogares colombianos

    Directory of Open Access Journals (Sweden)

    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.

  11. Estimation de l'aléa sismique dans les Andes nord équatoriennes

    Directory of Open Access Journals (Sweden)

    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

  12. Stable isotope evidence for formation from magmatic fluids of the mineralized breccias in the Los Bronces and El Teniente copper deposits, Central Chile

    International Nuclear Information System (INIS)

    Skewes, M.A; Arevalo, A; Holmgren, C.; Stern, C.R

    2001-01-01

    The giant Miocene and Pliocene Rio Blanco-Los Bronces (Warnaars et al., 1985; Serrano et al., 1996; Vargas et al., 1999) and El Teniente (Camus, 1975; Cuadra, 1986; Skewes and Arevalo, 2000) copper deposits of central Chile are among the largest copper deposits in the world. Hypogene copper ore is more significant than supergene ore in these deposits, and most of the hypogene copper occurs in the matrix of multiple clusters of breccias (Skewes and Stern, 1994; 1995). The origin of the large mineralized breccia pipes in these and other Andean copper deposits has been attributed to the explosive expansion of magmatic aqueous fluids derived from cooling plutons (Emmons, 1938; Kents, 1964; Warnaars et al., 1985; Sillitoe, 1985; Skewes and Stern, 1994, 1995). Warnaars et al. (1985) and Skewes and Stern (1996) suggested that mineral deposition in the matrix of these breccias took place by the rapid cooling of the same magmatic fluids that generated the brecciation. Highly saline, high-temperature magmatic fluid inclusions occur in quartz and tourmaline in the matrix of these breccias (Holmgren et al., 1988; Vargas et al., 1999; Skewes et al., 2001) (au)

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

    Directory of Open Access Journals (Sweden)

    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

  14. Peñaranda Supelano, Daniel Ricardo. 2015. Guerra propia, guerra ajena. Conflictos armados y reconstrucción identitaria en los Andes colombianos. El movimiento armado Quintín Lame. Bogotá: Cnmh, Iepri. ISBN: 978-958-59068-5-3

    Directory of Open Access Journals (Sweden)

    Juan José Escobar López

    2018-01-01

    Full Text Available ¿Cuál es la relación entre el conflicto armado y las comunidades indígenas? ¿De qué manera y por qué medios han buscado reivindicar su cultura, su lengua, a la vez que proteger su territorio y su identidad estos grupos? ¿Cómo se han visto afectados, usados y desprotegidos por los grupos al margen de la ley los pueblos indígenas? Tantas preguntas buscan responder esta investigación, que nos interesa analizar, entonces, su papel historiográfico en la tarea por reconstruir la memoria histórica.

  15. 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…

  16. 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...

  17. 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.

  18. 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.

  19. 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.

  20. Evaluación de MDE para la estimación de volúmenes por procesos de erosión aplicando análisis de autocorrelación espacial en una cuenca de los andes venezolanos. Caso de estudio: microcuenca torrencial La Machirí

    Directory of Open Access Journals (Sweden)

    Cristopher Camargo Roa

    2014-06-01

    Full Text Available Los modelos digitales de elevación (MDE, como representación visual de las formas del relieve y de los valores de altura, han sido muy útiles para estudiar los aspectos relacionados con la topografía de un área. Esta investigación se realizó en un área de 3.39 km2 de la microcuenca torrencial La Machirí (estado Táchira, Venezuela. Tuvo por objetivo evaluar un MDE obtenido por un proceso de fotogrametría digital cotejado a su vez con un MDE elaborado a partir de la edición de curvas de nivel existentes en cartas topográficas. Para ello se aplicaron métodos como el análisis exploratorio de datos espaciales (ESDA y la geoestadística de puntos (análisis de mínima distancia, análisis de patrones espaciales, variograma y superficie variográfica. Se pudo determinar una diferencia existente entre ambos modelos, resultado de la sumatoria de los errores generados, en primer lugar, por la distribución espacial de los puntos de control señalados para el proceso fotogramétrico (número de puntos menores al valor de una distribución normal, posible sesgo espacial entre los puntos y manifestación de fenómenos de dependencia espacial, seguido del error generado a partir del método de interpolación aplicado durante el mismo y el error resultante originado por el comportamiento local de los procesos de erosión en el área. La primera valoración arrojó una diferencia en la superficie de área de 0.57 ha y en volumen de 9.41 hm3 en ambos MDE. Un análisis sectorizado permitió determinar la falta de al menos 3 puntos de control para obtener un MDE más satisfactorio.

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Satisfacción laboral y el desempeño laboral de los docentes de la Asociación Educativa Adventista Central Este en el año 2014.

    OpenAIRE

    Lozano Huari, Abeli Humberto

    2014-01-01

    Esta investigación se desarrolló auxiliada por objeto: determinar en qué medida se relaciona la Satisfacción Laboral en el desempeño Laboral de los docentes de la Asociación Educativa Adventista Central Este. Se entiende que la satisfacción laboral constituye el valor fundamental del desempeño laboral de los docentes. Se ha trabajado con 74 docentes, la muestra representativa, aplicándose el cuestionario para estudiar la variable predictora: satisfacción laboral con sus dimensiones: satisfacc...

  3. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Fósforo total, fósforo fítico y actividad fitásica en los frutos de árboles forrajeros de los Llanos Centrales de Venezuela Total phosphorus, phytic phosphorus and phytase activity in the fruits of forage trees from the Central Plains, Venezuela

    Directory of Open Access Journals (Sweden)

    P Pizzani

    2009-06-01

    Full Text Available Con el objetivo de conocer la concentración de fósforo total (PT, fósforo fítico (PF y la actividad fitásica intrínseca (AFi de algunos frutos de árboles de interés forrajero de los Llanos Centrales de Venezuela: samán (Pithecellobium saman, carocaro (Enterolobium cyclocarpum, cují hediondo (Acacia macracantha, cañafistolillo (Cassia emarginata, caruto (Genipa americana, dividive (Caesalpinia coriaria, granadillo (Caesalpinia granadillo, guamacho (Pereskia guamacho, tiamo (Acacia glomerosa, guácimo (Guazuma ulmifolia, merecure (Licania pyrifolia y cují blanco (Prosopis juliflora, se realizó un ensayo mediante un diseño totalmente aleatorizado y diez réplicas. Los resultados indicaron valores de PT entre 0,08 y 0,38% y los contenidos de PF oscilaron entre 0,02 y 0,28%; ambas variables presentaron diferencias significativas entre especies (PWith the objective of learning the total phosphorus (TP and phytic phosphorus (PP concentrations and the intrinsic phytase activity (PAi in some fruits of forage trees from the Central Plains, Venezuela: Pithecellobium saman, Enterolobium cyclocarpum, Acacia macracantha, Cassia emarginata, Genipa americana, Caesalpinia coriaria, Caesalpinia granadillo, Pereskia guamacho, Acacia glomerosa, Guazuma ulmifolia, Licania pyrifolia and Prosopis juliflora, a trial was conducted by means of a completely randomized design and ten replications. The results indicated TP values between 0,08 and 0,38% and the PP contents oscillated between 0,02 and 0,28%; both variables showed significant differences among species (P<0,05. P. guamacho had the highest TP and PP concentration. The PAi of 91,7% of the fruits was higher than 100 Ukg-1; the rest showed values between 94 and 95 Ukg-1. The PP content was highly correlated to TP concentration (r = 0,97; P<0,01. However, the PAi did not show significant relationship to the TP and PP values. Only L. pyrifolia recorded a lower value (0,08%. The PP content, as percentage

  6. 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

  7. 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...

  8. 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.

  9. Composición por especies y tallas de los peces en la laguna Barra de Navidad, Pacífico central mexicano

    Directory of Open Access Journals (Sweden)

    Gaspar González-Sansón

    2014-03-01

    Full Text Available Las lagunas costeras son consideradas áreas de crianza importantes para muchas especies de peces costeros. La laguna costera Barra de Navidad (3.76km² es importante para la economía local y soporta un desarrollo turístico y pesquerías artesanales. Sin embargo, el rol de esta laguna en la dinámica de las poblaciones de peces costeros es poco conocido. Los objetivos de la investigación fueron: caracterizar el agua de la laguna y las condiciones climáticas relacionadas, elaborar el elenco sistemático de la ictiofauna y estimar la proporción de juveniles en el total de individuos capturados de las especies más abundantes. Las operaciones de recolecta de peces se realizaron entre marzo 2011 y febrero 2012. Se utilizaron varios artes de pesca diferentes que incluyeron atarraya, chinchorro playero y redes de agalla con cuatro tamaños de malla diferentes. Se midieron las variables físicas y químicas en épocas de lluvias y de secas. La laguna es euhalina (salinidad 30-40 ups la mayor parte del tiempo, aunque en determinados periodos cortos puede tener características mixopolihalinas (salinidad 18-30 ups. Las concentraciones de clorofila y nutrientes indican que la laguna está eutrofizada. La temperatura media del agua varió estacionalmente de 24.9°C (abril, pleamar a 31.4°C (octubre, bajamar. Se recolectaron en total 36 448 individuos, pertenecientes a 92 especies, de las cuales 31 tienen una relevancia ecológica con base en el número de individuos capturados. Las especies dominantes fueron: Anchoa spp. (44.6%, Diapterus peruvianus (10.5%, Eucinostomus currani (8.1%, Cetengraulis mysticetus (7.8%, Mugil curema (5.2% y Opisthonema libertate (4.5%. La laguna es un hábitat de juveniles importante para 22 de las 31 especies más abundantes. Estas incluyeron algunas especies de importancia comercial como los pargos (Lutjanus argentiventris, L. colorado y L. novemfasciatus, el robalo (Centropomus nigrescens y la lisa (Mugil curema. Otras

  10. 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.

  11. 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.

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

    Science.gov (United States)

    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.

  13. 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

  14. 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

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

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    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

  16. La vertebración territorial en regiones de alta especialización: Valle Central de Chile. Alcances para el desarrollo de zonas rezagadas en torno a los recursos naturales

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    ALBERTO GARCÍA-HUIDOBRO

    2010-04-01

    Full Text Available Los procesos de reestructuración económica y la apertura de los mercados han generado múltiples y variadas consecuencias sobre nuestros territorios. Quizás para Chile, como para otros países latinoamericanos, uno de los más importantes procesos a nivel regional es el desarrollo de espacios altamente especializados o regiones-commodities. Distintos trabajos académicos señalan que interiormente, en conjunto con áreas de gran competitividad, se están generando áreas rezagadas o alejadas de los dinamismos económicos. Por lo tanto: ¿ En qué ha derivado su modelo de vertebración territorial y su sistema de centros poblados ? ¿Cuáles son las características de estas áreas rezagadas ? Y por ende, ¿cuáles son los desafíos a los cuales se enfrentan? El Valle Central de Chile es una de estas áreas donde se evidencia dicha especialización. Por tanto, analizaremos la estructura física territorial en las que han derivado estas regiones y el papel que cumplen sus centros poblados en los nuevos escenarios. A partir de la caracterización de su vertebración territorial avanzaremos hacia la definición de sus zonas menos favorecidas, e intentaremos generar algunas hipótesis que respondan a sus desafíos y requerimientos futuros.Economic restructuring processes and market opening have generated multiple and varied consequences in our territories. Perhaps for Chile, as with other Latin American countries, one of the most important processes at the regional level is the development of highly specialized spaces or commodity-regions. Different academic work indicates that within these spaces, as well as areas of high competitiveness, there are also backward areas with limited economic dynamism. Consequently: What has happened to the model of a territorial spine and system of population center? What are the characteristics of these backward areas? In addition, what are the challenges to be faced? Chile's Central Valley is one of the areas

  17. Geochemical composition of river loads in the Tropical Andes: first insights from the Ecuadorian Andes

    Science.gov (United States)

    Tenorio Poma, Gustavo; Govers, Gerard; Vanacker, Veerle; Bouillon, Steven; Álvarez, Lenín; Zhiminaicela, Santiago

    2015-04-01

    Processes governing the transport of total suspended material (TSM), total dissolved solids (TDS) and particulate organic carbon (POC) are currently not well known for Tropical Andean river systems. We analyzed the geochemical behavior and the budgets of the particulate and dissolved loads for several sub-catchments in the Paute River basin in the southern Ecuadorian Andes, and examined how anthropogenic activities influenced the dynamics of riverine suspended and dissolved loads. We gathered a large dataset by regularly sampling 8 rivers for their TSM, POC, and TDS. Furthermore, we determined the major elements in the dissolved load and stable isotope composition (δ13C) of both the POC, and the dissolved inorganic carbon (DIC). The rivers that were sampled flow through a wide range of land uses including: 3 nature conservation areas (100 - 300 Km²), an intensive grassland and arable zone (142 Km²); downstream of two cities (1611 and 443 Km²), and 2 degraded basins (286 and 2492 Km²). We described the geochemical characteristics of the river loads both qualitatively and quantitatively. Important differences in TSM, POC and TDS yields were found between rivers: the concentration of these loads increases according with human activities within the basins. For all rivers, TSM, TDS and POC concentrations were dependent on discharge. Overall, a clear relation between TSM and POC (r²=0.62) was observed in all tributaries. The C:N ratios and δ13CPOC suggest that the POC in most rivers is mainly derived from soil organic matter eroded from soils dominated by C3 vegetation (δ13CPOC < -22‰). Low Ca:Si ratios (<1)and high δ13CDIC (-9 to -4) in the Yanuncay, Tomebamba1 and Machángara, rivers suggest that weathering of silica rocks is dominant in these catchments, and that the DIC is mainly derived from the soil or atmospheric CO2. In contrast, the Ca:Si ratio was high for the Burgay and Jadán rivers (1-13), and the low δ13CDIC values (-9 to -15) suggest that

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

    Science.gov (United States)

    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

  19. The economic impact of Los Alamos National Laboratory on North-Central New Mexico and the state of New Mexico. Fiscal Year 1995

    International Nuclear Information System (INIS)

    Lansford, R.R.; Ben-David, S.

    1996-08-01

    Los Alamos National Laboratory is a multidisciplinary, multiprogram laboratory with a mission to enhance national military and economic security through science and technology. Its mission is to reduce the nuclear danger through stewardship of the nation's nuclear stockpile and through its nonproliferation and verification activities. An important secondary mission is to promote U.S. industrial competitiveness by working with U.S. companies in technology transfer and technology development partnerships. Los Alamos has provided technical assistance to over 70 small New Mexico businesses enabling economic development activities in the region and state

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

    Science.gov (United States)

    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.

  1. Los Neutrinos Los Neutrinos

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    Julián Félix

    2012-02-01

    Full Text Available From all the proposals to understand the structure of matter, and the way the natural world is conformed, the one about neutrinos is the most enigmatic, abstract, and foreign to immediate experience; however, this is the one that has delved more deeply over the nearly eighty years since it was formulated by Wolfgang Pauli –in 1930- as a radical proposition to understand nucleon decay, and the decay of other particles, without the violation of the principle of conservation of energy and momentum at subatomic level. This proposition has evolved through the years, and from Pauli’s original idea only the basic elements remain.This article contains the tale of the hypothesis of neutrinos, its early history, its evolution up to present day, and the efforts done nowadays to study them. In summary, this is the physics of neutrinos. De todas las propuestas para entender la estructura de la materia, y la conformación del mundo natural, los neutrinos es la más enigmática, abstracta, y ajena a la experiencia inmediata; sin embargo, es la que más hondo ha ido calando a lo largo de los ya casi ochenta años de haber sido formulada por Wolfgang Pauli –en el año 1930- como una medida radical para entender el decaimiento de los nucleones, y otras partículas, sin que se violara el principio de la conservación de la energía y del momento a nivel subatómico. La propuesta ha evolucionado a lo largo de los años, y de la idea original de Pauli ya sólo lo básico permanece. En este artículo está el relato de la hipótesis de los neutrinos, su historia primera, su evolución hasta el presente, los esfuerzos que en la actualidad se realizan para estudiarlos. En breve, ésta es la física de los neutrinos.

  2. Comportamento dos quimiorreflexos central e periférico na insuficiência cardíaca Comportamiento de los quimiorreflejos central y periférico en la insuficiencia cardíaca Behavior of central and peripheral chemoreflexes in heart failure

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    Guilherme Veiga Guimarães

    2011-02-01

    Full Text Available A síndrome da insuficiência cardíaca (IC pode ser definida como via final de qualquer forma de doença cardíaca. Os reflexos cardiovasculares simpatoinibitórios como o reflexo arterial barorreceptor estão significativamente suprimidos na IC. Pacientes com IC apresentam maior ventilação para determinada carga de trabalho quando comparados a indivíduos normais. Esse fato gera baixa eficiência ventilatória e relaciona-se com maior ventilação relativa à produção de gás carbônico, que é um preditor de mau prognóstico, além de ser um fator limitante ao exercício. Há evidências de que o desequilíbrio autonômico contribua para a patogênese e a progressão da insuficiência cardíaca. Os quimiorreflexos são os principais mecanismos de controle e regulação das respostas ventilatórias às mudanças de concentração do oxigênio e gás carbônico arterial. A ativação do quimiorreflexo causa aumento da atividade simpática, frequência cardíaca, pressão arterial e volume minuto. No entanto, o aumento do volume minuto e da pressão arterial, pelo feedback negativo provocam inibição da resposta simpática à ativação do quimiorreflexo. Apesar das alterações funcionais dos reflexos, seu comportamento em condições normais e patológicas, especialmente sua contribuição para o estado simpatoexcitatório encontrado na IC, não tem sido amplamente estudado. Dessa forma, esta revisão tem por objetivo integrar os conhecimentos a respeito dos quimiorreflexos central e periférico na síndrome da insuficiência cardíaca, bem como esclarecer a influência da terapêutica medicamentosa da insuficiência cardíaca nos quimiorreflexos.El síndrome de insuficiencia cardíaca (IC puede ser definido como vía final de cualquier forma de enfermedad cardíaca. Los reflejos cardiovasculares simpáticoinhibitorios como el reflejo arterial barorreceptor están significativamente suprimidos en la IC. Pacientes con IC presentan mayor

  3. 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.

  4. Estructura comunitaria de diatomeas presentes en los sedimentos superficiales de ocho lagos andinos de Chile central Diatoms community structure in superficial sediments of eight Andean lakes of central Chile

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    INGRID E ALVIAL

    2008-03-01

    Full Text Available En este trabajo se analizó la estructura comunitaria de diatomeas depositadas en los sedimentos superficiales de ocho lagos andinos chilenos ubicados entre los 32°49' y 38°48' S. Se encontró un total de 99 taxa de diatomeas, distribuidos en 48 géneros. Del total de taxa, 74 fueron identificados a nivel de especie siendo todos ellos cosmopolitas a excepción de Eunotia andinofrequens, Gomphonema punae, Pinnularia araucanensis y Pinnularia acidicola, entre otras, que están descritos solo para el Hemisferio Sur. Por otro lado, las muestras analizadas presentaron distinta composición florística de diatomeas. De esta manera, en los ensambles diatomológicos depositados en los sedimentos de las lagunas de altura Ocho, Huifa, Ensueño y Negra ubicadas sobre los 2.860 m del nivel del mar, abundaron especies bentónicas, típicas de aguas oligotróficas y acidas como Achnanthidium exiguum, Achnanthidium minutissimum, Encyonema minutum, Pinnularia acidicola y Planothidium lanceolatum. En los ensambles diatomológicos de los lagos Galletué, Icalma y Laja, ubicados bajo los 1.360 m del nivel del mar, abundaron diatomeas planctónicas, características de aguas alcalinas y mesotróficas como Asterionella formosa, Aulacoseira distans, Aulacoseira granulata, Cyclotella stelligera y Rhopalodia gibbaIn this research the taxonomic structure of diatoms in sediments of high mountain lakes was studied. These lakes are located in Chile between 32°49' and 38°48' S in the Andean Cordillera. A total of 99 diatom taxa distributed in 48 genera were identified and all this taxa are cosmopolitan excepting a Eunotia andinofrequens, Gomphonema punae, Pinnularia araucanensis and Pinnularia acidicola, which are know only for the Southern Hemisphere. The assemblages of diatoms were different in the studied lakes. So the high mountain lakes Ocho, Huifa, Ensueño and Negra, dominated benthic diatoms which are typical of oligotrophic and acid waters as Achnanthidium

  5. 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.

  6. 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.

  7. Características bio-ecológicas en poblaciones de lombrices (Oligochaeta: Glossoscolecidae de una sabana natural y una protegida en los llanos centrales de Venezuela

    Directory of Open Access Journals (Sweden)

    Luis Hernández

    2012-09-01

    Full Text Available Las lombrices de tierra tienen un papel importante en el ciclado de nutrientes y el mantenimiento de la fertilidad de los suelos. En este estudio se empleo el método de extracción manual para determinar la densidad y la biomasa de las lombrices de tierra en diferentes profundidades y en diferentes estaciones, seleccionando al azar cinco monolitos de 25cm2x30cm, ubicados en un área de 90x90m en una Sabana Protegida (SP y una Sabana Natural Intervenida (SNI. Adicionalmente, se estimó la densidad de los capullos, se analizaron las clases de etapas de desarrollo y se clasificaron los individuos en categorías ecológicas. Se estimó la humedad del suelo, la capacidad de campo, la temperatura, la densidad aparente y la textura del suelo. La SP presentó mejores condiciones físicas en el suelo que la SNI, mientras que la actividad de las lombrices de tierra estuvo limitada a los meses de lluvia y se observó un patrón de migración estacional en el perfil del suelo. En la SNI sólo se observó presencia de individuos en agosto y no se encontró diferencia significativa en sus biomasas con la SP. Los sistemas estuvieron dominados por individuos jóvenes con una categoría ecológica de tipo endo-anécica pertenecientes a la familia

  8. Análisis de los efectos de 12 semanas de entrenamiento en la zona Central Core, en jugadoras de voleibol gimnastas de rítmica y su influencia en el dolor de espalda lumbar

    OpenAIRE

    Esteban García, Paula

    2016-01-01

    El dolor de espalda lumbar afecta entorno el 85-90% de la población, pudiendo también encontrarse como patología, en la población deportista. Se ha determinado, que deportes como la gimnasia rítmica y el voleibol, tienen como una de las lesiones con mayor incidencia, el dolor de espalda lumbar. Existe una gran tendencia en los últimos años, en la aplicación de programas de entrenamiento sobre la zona central CORE, en población con dolor crónico lumbar, encontrando reducciones en la intensidad...

  9. Aplicación de modelos en los sistemas agrícolas de secano de la meseta central : Simulación de rotaciones y modelado de la arquitectura de la planta en leguminosas

    OpenAIRE

    Hernández Díaz-Ambrona, Carlos Gregorio

    1999-01-01

    Este trabajo profundiza en el estudio de los sistemas agrícolas de secano de la Meseta Central. Sobre la base de la alternativa tradicional ce^eal^arbecho, se han estudiado durante tres años de cultivo 1995/96, 1996/97 y 1997/98 seis rotaciones diferentes: monocultivo de cebada (Hordeum vulgare L.), cebada/barbecho, cebada/habas (Viciafaba L.), cebada/guisantes {Pisum sativum L.), cebada/habas/barbecho y cebada/guisantes/barbecho. Entre las rotaciones, se ha comparado la biomasa, el rendimien...

  10. 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

  11. Doble difusión a partir de mediciones de microestructura en los canales Martínez y Baker, Patagonia chilena central (47,85°S

    Directory of Open Access Journals (Sweden)

    Iván Pérez-Santos

    2013-03-01

    Full Text Available Con un microperfilador SCAMP (Self Contained Autonomous MicroProfile se detectó un proceso de Doble Difusión Convectiva (DDC, en los canales Martínez y Baker de la Patagonia central, Chile. Este perfilador midió temperatura y salinidad en la columna de agua con una resolución del orden de milímetros. El muestreo se efectuó en diciembre 2011, en 19 estaciones oceanográficas de ~55 m de profundidad. Los registros del microperfilador permitieron detectar la formación de escaleras termohalinas que caracterizan la formación de la DDC. Por medio del ángulo de Turner se confirmó que debajo de una capa superficial fuertemente estratificada (7-10 m se registraron eventos de DDC a profundidades entre 15 y 45 m. La DDC fue débil en la mayoría de los registros pero se evidenciaron eventos fuertes entre 15 y 40 m. En la capa subsuperficial, su origen se debió al intercalamiento de las masas aguas estuarinas (aguas frías y menos saladas encima de las oceánicas (aguas más cálidas y saladas, mientras que en la superficie la interacción océano-atmósfera favoreció su ocurrencia. La DDC en conjunto con el viento, las mareas y las ondas internas, puede constituir un mecanismo importante para la mezcla vertical, influenciando los flujos de calor, el hábitat de las especies marinas en estas profundidades y la exportación de carbono hacia los sedimentos.

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