1000 resultados para Argentina, Presidente (1868-1874 : Sarmiento)


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ABSTRACT Seven sites were examined in the Challhuaco-Ñireco system, located in the reserve of the Nahuel Huapi National Park, however part of the catchment is urbanized, being San Carlos de Bariloche (150,000 inhabitants) placed in the lower part of the basin. Physico-chemical variables were measured and benthic macroinvertebrates were collected during three consecutive years at seven sites from the headwater to the river outlet. Sites near the source of the river were characterised by Plecoptera, Ephemeroptera, Trichoptera and Diptera, whereas sites close to the river mouth were dominated by Diptera, Oligochaeta and Mollusca. Regarding functional feeding groups, collector-gatherers were dominant at all sites and this pattern was consistent among years. Ordination Analysis (RDA) revealed that species assemblages distribution responded to the climatic and topographic gradient (temperature and elevation), but also were associated with variables related to human impact (conductivity, nitrate and phosphate contents). Species assemblages at headwaters were mostly represented by sensitive insects, whereas tolerant taxa such as Tubificidae, Lumbriculidae, Chironomidae and crustacean Aegla sp. were dominant at urbanised sites. Regarding macroinvertebrate metrics employed, total richness, EPT taxa, Shannon diversity index and Biotic Monitoring Patagonian Stream index resulted fairly consistent and evidenced different levels of disturbances at the stream, meaning that this measures are suitable for evaluation of the status of Patagonian mountain streams.

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ABSTRACT Mugil liza Valenciennes, 1836 is an economically important food fish and has been recommended for aquaculture in South America. A total of 278 fishes were collected in the spring and summer of 2009 and 2010. These fish were sorted into sample groups according to their size class. We used Bayesian statistics and 95% credible intervals for each parameter tested were calculated. Fish studied harbored a total of 15 different species of parasites. Diversity of parasite species found on Mugil liza was greatest at the S.R.C. collection site, but evidenced a lower species richness than at A.R. site. The 1st size fishes of both sites evidenced greater parasite diversity than either 2nd or 3rd size fish. Differences observed could be explained by the different use of habitat types at the two sites or differential susceptibility to infection by parasites. The dominance of D. fastigatainfluenced observed results of lower community diversity indexes. New works elucidating different parasite life cycles within juvenile and adults ofM. liza in Argentina, promise to be important for determining the risk of the parasitism by zoonotic metacercariae A. (P.) longa and use of this fish as food and an economic resource, and the possible use of mullet parasites in other promising fields as indicators of biodiversity, and/ or water contamination.

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ABSTRACT Adults (male and female) and pupae of Chuspilepia saltenia gen. nov., sp. nov. were collected in tree holes in the Yungas rainforest, near San Ramón de la Nueva Orán city, Salta province, Argentina. It was not possible to place this new species in any known genera using the available keys and published descriptions, thus a new genus is proposed for the Neotropical region of Argentina.

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ABSTRACT Quantitative evaluations of species distributional congruence allow evaluating previously proposed biogeographic regionalization and even identify undetected areas of endemism. The geographic scenery of Northwestern Argentina offers ideal conditions for the study of distributional patterns of species since the boundaries of a diverse group of biomes converge in a relatively small region, which also includes a diverse fauna of mammals. In this paper we applied a grid-based explicit method in order to recognize Patterns of Distributional Congruence (PDCs) and Areas of Endemism (AEs), and the species (native but non-endemic and endemic, respectively) that determine them. Also, we relate these distributional patterns to traditional biogeographic divisions of the study region and with a very recent phytogeographic study and we reconsider what previously rejected as 'spurious' areas. Finally, we assessed the generality of the patterns found. The analysis resulted in 165 consensus areas, characterized by seven species of marsupials, 28 species of bats, and 63 species of rodents, which represents a large percentage of the total species (10, 41, and 73, respectively). Twenty-five percent of the species that characterize consensus areas are endemic to the study region and define six AEs in strict sense while 12 PDCs are mainly defined by widely distributed species. While detailed quantitative analyses of plant species distribution data made by other authors does not result in units that correspond to Cabrera's phytogeographic divisions at this spatial scale, analyses of animal species distribution data does. We were able to identify previously unknown meaningful faunal patterns and more accurately define those already identified. We identify PDCs and AEs that conform Eastern Andean Slopes Patterns, Western High Andes Patterns, and Merged Eastern and Western Andean Slopes Patterns, some of which are re-interpreted at the light of known patterns of the endemic vascular flora. Endemism do not declines towards the south, but do declines towards the west of the study region. Peaks of endemism are found in the eastern Andean slopes in Jujuy and Tucumán/Catamarca, and in the western Andean biomes in Tucumán/Catamarca. The principal habitat types for endemic small mammal species are the eastern humid Andean slopes. Notwithstanding, arid/semi-arid biomes and humid landscapes are represented by the same number of AEs. Rodent species define 15 of the 18 General Patterns, and only in one they have no participation at all. Clearly, at this spatial scale, non-flying mammals, particularly rodents, are biogeographically more valuable species than flying mammals (bat species).

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Ixodidae of the Argentine Republic are studied by the Author based on 71 lots of material, sent by Prof. Salvador Mazza, comprising 13 different species, two of which are found in Argentine territory: Haemaphysalis kochi Arag. and Amblyomma parvitarsum Nn. The author admits the existence in Argentina of 23 species of Ixodidae, but such number may still increase along with the development of the studies on the subject. In this paper, the Ornithodoros classified by Barbará and Dios as Ornithodoros turicata, is sunk by the Author in synonymy with O. rostratus Arag. not merely on the strength of the material at his disposal, but also by the plates published by the Argentine authors. The following species are also placed in synonymy: Amblyomma altiplanum Dios, 1917 (= Amblyomma parvitarsum Nn., 1899), Amblyomma concolor, Nn., 1899 (=Amblyomma auriculare Conil, 1877) Amblyomma furcula Donitz, 1907 (= Amblyomma neumani Ribaga, 1902). In the Author's opinion Amblyomma striatum C. L. Koch, 1844 and Amblyomma fossum Nn. are distinct species, so that the same Amblyomma ovale for both should no longer subsist as L. C. Robinson proposes. The Author, moreover, shows his doubts upon the existence in Argentine of Aponomma laeve, Nn., 1899 and Dermacentor triangulus Nn., 1899, as they have not been seen any more and in South-America no representatives of the genera Aponomma and Dermacentor are known.

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A study of and addicional collection of Argentine ixodidae is made on material send to the Author by Professor Salvador Mazza of Departamento de pathologia do Norte - Jujuy and Professor Doello Jurado of the Museu Rivadavia. There was examined 37 lots of Ixodidae. Among them there were found the nymph of Ixodes auritulus Nn. and 3 other species already known on the South American fauna and from which there was til yet no record in Argentine; they are Ixodes ricinus, Amblyomma parvum and Amblyomma pseudo-concolor.

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Los consorcios han sido una de las novedades más influyentes en la realidad bibliotecaria mundial de los últimos cinco años. Su expansión territorial y en actividades los ha convertido en un fenómeno que ha cambiado profundamente las formas tradicionales de definir los servicios bibliotecarios. El examen atento de las actividades que ha desarrollado el Consorcio de Bibliotecas Universitarias de Cataluña (CBUC) en el ámbito de las bibliotecas digitales es una muestra de las posibilidades de cooperación existentes en estos inicios del Siglo XXI. El CBUC inició sus actividades de contratación de contenidos digitales en el 1998. Los productos y servicios licenciados se agruparon bajo el nombre de Biblioteca Digital de Catalunya (BDC). La BDC contiene actualmente unas 6.800 revistas-e, 58 BBDD y 4.100 libros-e. De forma bastante paralela en el tiempo nacieron un servidor de sumarios electrónicos de revistas y un servidor de tesis doctorales a texto completo. La evolución de las necesidades de las bibliotecas ha comportado que hoy en el CBUC se tenga la visión de la BDC como un servicio formado de dos grandes partes: a) los productos exteriores sujetos a contratación y accesibles remotamente a través de servicios comerciales, y, b) servidores de aquellos objetos digitales generados en el ámbito del CBUC y que solo pueden ser puestos en la red por nosotros mismos. Para gestionar esta segunda parte de la BDC debemos constituir almacenes o repositorios digitales. Entre las diferentes posibilidades, el CBUC ha optado por crear repositorios institucionales colectivos de diferente tipo según los materiales que contienen. Hasta el momento se han creado tres repositorios: uno para tesis, uno para revistas y uno para literatura gris de investigación. Está previsto crear un cuarto repositorio para imágenes. La ponencia finaliza con los aprendizajes del CBUC en materia de repositorios. El principal es que la mayor dificultad para crearlos no son los elementos tecnológicos sino establecer mecanismos de relación con el profesorado y la universidad para que los diferentes documentos creados de forma electrónica pasen a formar parte de los repositorios institucionales correspondientes.

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t.11 (1881)

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t.23 (1887)

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Investigación producida a partir de una estancia en en las ciudades de Buenos Aires (Argentina) y Montevideo (Uruguay)durante los meses de octubre i noviembre del 2005. Se detalla el trabajo de recogida de datos en esta zona para la realización de una tesis doctoral, cuya temática será el estudio histórico del surgimiento y afianzamiento del estado nacional argentino y de la concepción particular de “homogeneidad nacional” establecida en su interior. Se considera que la comparación de esta formación con el estado nacional uruguayo puede ser muy provechosa en el aislamiento de esta particularidad. Para ello, se ha buscado en los archivos locales información relacionada con el grupo específico de los descendientes de esclavos africanos. Estos grupos en ambas ciudades mantenían publicaciones periódicas, cuyo número y cantidad era alto, y que permanecen aún inéditos y sin ser trabajados exhaustivamente por otros investigadores. Por lo tanto, el objetivo principal de la estancia fuera de Cataluña era la continuación del vaciado de fondos de archivo de las ciudades de Buenos Aires (Argentina) y Montevideo (Uruguay) –indispensables para cualquier investigación de corte histórico- y la recopilación de información bibliográfica de trabajos científicos locales. Asimismo, se han realizado de entrevistas a historiadores y expertos en el tema en investigación, como así a descendientes de esclavos del Río de la Plata. Este viaje ha permitido ampliar la base material que sustentará la tesis doctoral con fuentes específicas e inéditas, que no han sido trabajadas hasta el momento.