495 research outputs found

    Darwin's Geological Research in Argentina

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    On the occasion of the 200th. anniversary of Charles Darwin´s birth, the Asociación Geológica Argentina decided to prepare a special issue devoted to the geological research undertaken by Darwin in Argentina. As it is well known, during his journeys on board HMS Beagle under the command of Captain Robert FitzRoy, he had the opportunity to survey overland different areas of South America. Darwin spent nearly three years - between August 1832 and April 1835 - visiting and studying different regions of our country. The aim of this special issue is to analyze his important geological observations and to emphasize the validity of many of his ideas under a 21st Century perspective. In order to accomplish this aim, several key localities that Darwin examined from a geological point of view during his voyage were selected. Such an analysis was carried out by several geologists and paleontologists well acquainted with the diverse problems that Darwin faced along his journeys in Argentina.Fil: Ramos, Victor Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentin

    A revision of the type specimens of Tertiary molluscs from Chile and Argentina described by d`Orbigny (1842), Sowerby (1846), and Hupé (1854)

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    Fil: Griffin, Miguel. Facultad de Ciencias Exactas y Naturales; Universidad Nacional de La PampaFil: Nielsen, Sven N.. GeoForschungsZentrum Potsdam; Potsdam; German

    Cenozoic Ampullinidae and Naticidae (Mollusca, Gastropoda) from Patagonia, Argentina

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    A revision of the Cenozoic Ampullinidae and Naticidae from a wide range of localities and stratigraphic units in Patagonia revealed the occurrence there of thirteen species referable to these families. Ampullinid species described are Tejonia? tapia (Feruglio, 1935); Tejonia arroyoensis n. sp. and Pseudamaura dubia (Petersen, 1946). Naticids are represented by the following valid species: ‘‘Natica’’ entreriana Borchert, 1901; Euspira patagonica (Philippi, 1845); Notocochlis borrelloi (Brunet, 1995); Bulbus subtenuis (Ihering, 1897); Polinices santacruzensis Ihering, 1907; Polinices puntarenasensis Ihering, 1907; ‘‘Polinices’’ ortmanni Ihering, 1907 (nomen dubium); Polinices mina n. sp.; Glossaulax secundum (Rochebrune and Mabille, 1885); and Darwinices claudiae n. gen. n. sp.Facultad de Ciencias Naturales y Muse

    Cenozoic Ampullinidae and Naticidae (Mollusca, Gastropoda) from Patagonia, Argentina

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    A revision of the Cenozoic Ampullinidae and Naticidae from a wide range of localities and stratigraphic units in Patagonia revealed the occurrence there of thirteen species referable to these families. Ampullinid species described are Tejonia? tapia (Feruglio, 1935); Tejonia arroyoensis n. sp. and Pseudamaura dubia (Petersen, 1946). Naticids are represented by the following valid species: ‘‘Natica’’ entreriana Borchert, 1901; Euspira patagonica (Philippi, 1845); Notocochlis borrelloi (Brunet, 1995); Bulbus subtenuis (Ihering, 1897); Polinices santacruzensis Ihering, 1907; Polinices puntarenasensis Ihering, 1907; ‘‘Polinices’’ ortmanni Ihering, 1907 (nomen dubium); Polinices mina n. sp.; Glossaulax secundum (Rochebrune and Mabille, 1885); and Darwinices claudiae n. gen. n. sp.Facultad de Ciencias Naturales y Muse

    Homomorphic Routing: Private Data Forwarding in the Internet

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    We propose a new private routing and packet forwarding scheme for the Internet---Homomorphic Routing (HR)---that enables endpoints to communicate with one another without divulging source or destination addresses to the routers or service providers along the path. This is achieved via homomorphic encryption, whereby domains can match encrypted address ranges with encrypted destinations of packets without the need of decryption. Compared to approaches such as source or onion routing, HR is a hop-by-hop solution that allows current BGP-like decisions and traffic engineering techniques to remain largely unchanged, while per-flow state need not be maintained by routers. Preliminary performance evaluation shows that HR implies a tolerable computational overhead compared to plain text operations. Through aggregation we can compress inter-domain routing rules to around 5% of those required for current IPv6 and we can organize encrypted forwarding rules so that matching can be achieved in logarithmic time

    Introduction to the International Journal of Tour Guiding Research

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    IJTGR Volume 3 Table of Contents

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    IJTGR Volume 1(i) Table of Contents

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    Table of Contents for the Inaugural Issue of The International Journal of Tour Guiding Researc
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