7,800 research outputs found

    Long-range correlations and trends in Colombian seismic time series

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    We study long-range correlations and trends in time series extracted from the data of seismic events occurred from 1973 to 2011 in a rectangular region that contains mainly all the continental part of Colombia. The long-range correlations are detected by the calculation of the Hurst exponents for the time series of interevent intervals, separation distances, depth differences and magnitude differences. By using a modification of the classical R/SR/S method that has been developed to detect short-range correlations in time series, we find the existence of persistence for all the time series considered except for magnitude differences. We find also, by using the DFADFA until the third order, that the studied time series are not influenced by trends. Additionally, an analysis of the Hurst exponent as a function of the number of events in the time and the maximum window size is presented.Comment: 21 pages, 6 figures, 2 figures added, types corrected, accepted to be published in Physica

    The Odyssey Approach for Optimizing Federated SPARQL Queries

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    Answering queries over a federation of SPARQL endpoints requires combining data from more than one data source. Optimizing queries in such scenarios is particularly challenging not only because of (i) the large variety of possible query execution plans that correctly answer the query but also because (ii) there is only limited access to statistics about schema and instance data of remote sources. To overcome these challenges, most federated query engines rely on heuristics to reduce the space of possible query execution plans or on dynamic programming strategies to produce optimal plans. Nevertheless, these plans may still exhibit a high number of intermediate results or high execution times because of heuristics and inaccurate cost estimations. In this paper, we present Odyssey, an approach that uses statistics that allow for a more accurate cost estimation for federated queries and therefore enables Odyssey to produce better query execution plans. Our experimental results show that Odyssey produces query execution plans that are better in terms of data transfer and execution time than state-of-the-art optimizers. Our experiments using the FedBench benchmark show execution time gains of at least 25 times on average.Comment: 16 pages, 10 figure

    Double Threefold Degeneracies for Active and Sterile Neutrinos

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    We explore the possibility that the 3 active (doublet) neutrinos have nearly degenerate masses which are split only by the usual seesaw mechanism from 3 sterile (singlet) neutrinos in the presence of a softly broken A4A_4 symmetry. We take the unconventional view that the sterile neutrinos may be light, i.e. less than 1 keV, and discuss some very interesting and novel phenomenology, including a connection between the LSND neutrino data and solar neutrino oscillations.Comment: 8 pages, no figur

    Estudio comparativo entre dos protocolos anestésicos para la orquidectomía en el perro : sedación y bloqueo intratesticular frente a anestesia general

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    En este trabajo se utilizan dos protocolos anestésicos diferentes para la realización de la orquidectomía en el perro. Todos los pacientes reciben una mezcla intravenosa de medetomidina (10 μg/kg) y buprenorfina (20 μg/kg). En el primer grupo se realiza una infiltración intratesticular con lidocaína y en el segundo se administra bolos de propofol a efecto. Las cirugías son realizadas en todos los pacientes sin complicaciones. Comparativamente ambas técnicas se muestran apropiadas y seguras para este tipo de cirugía, pero la técnica local puede ofrecer varias ventajas, como son la mejor analgesia intraoperatoria, la recuperación más rápida del paciente y el menor coste económico de la misma. La aplicación de esta técnica local puede evitar el uso de anestesia general y hacer más sencillo el protocolo anestésico para este tipo de cirugías

    El Thesoro de los niños de Bernabé Soler (1615), adaptación del Thesaurus puerilis de Onofre Pou (1575)

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    El presente artículo analiza la adaptación española del diccionario bilingüe latín-catalán de Onofre Pou Thesaurus puerilis (1575), traducido por Bernabé Soler con el título Thesoro de los niños (1615). La autora plantea las principales características de la obra de Pou, disposición del contenido, estructura de los artículos, novedad desde un punto de vista lexicográfico y pedagógico, y estudia las principales aportaciones de la adaptación de Soler.This article analyses the Spanish adaptation of the bilingual Latin-Catalan dictionary by Onofre Pou, Thesaurus puerilis (1575), translated by Bernabé Soler under the title Thesoro de los niños (1615). The author expounds the essential characteristics of Pous work, the layout of the content, the organization of the articles, innovations from a lexicographical and pedagogical point of view, and examines the principal contributions offered by Solers adaptation

    El Thesoro de los niños de Bernabé Soler (1615), adaptación del Thesaurus puerilis de Onofre Pou (1575)

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    El presente artículo analiza la adaptación española del diccionario bilingüe latín-catalán de Onofre Pou Thesaurus puerilis (1575), traducido por Bernabé Soler con el título Thesoro de los niños (1615). La autora plantea las principales características de la obra de Pou, disposición del contenido, estructura de los artículos, novedad desde un punto de vista lexicográfico y pedagógico, y estudia las principales aportaciones de la adaptación de Soler.This article analyses the Spanish adaptation of the bilingual Latin-Catalan dictionary by Onofre Pou, Thesaurus puerilis (1575), translated by Bernabé Soler under the title Thesoro de los niños (1615). The author expounds the essential characteristics of Pou’s work, the layout of the content, the organization of the articles, innovations from a lexicographical and pedagogical point of view, and examines the principal contributions offered by Soler’s adaptation

    Co-evolution of RDF Datasets

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    Linking Data initiatives have fostered the publication of large number of RDF datasets in the Linked Open Data (LOD) cloud, as well as the development of query processing infrastructures to access these data in a federated fashion. However, different experimental studies have shown that availability of LOD datasets cannot be always ensured, being RDF data replication required for envisioning reliable federated query frameworks. Albeit enhancing data availability, RDF data replication requires synchronization and conflict resolution when replicas and source datasets are allowed to change data over time, i.e., co-evolution management needs to be provided to ensure consistency. In this paper, we tackle the problem of RDF data co-evolution and devise an approach for conflict resolution during co-evolution of RDF datasets. Our proposed approach is property-oriented and allows for exploiting semantics about RDF properties during co-evolution management. The quality of our approach is empirically evaluated in different scenarios on the DBpedia-live dataset. Experimental results suggest that proposed proposed techniques have a positive impact on the quality of data in source datasets and replicas.Comment: 18 pages, 4 figures, Accepted in ICWE, 201
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