705 research outputs found

    Prospects for the prevention of free radical disease, regarding cancer and cardiovascular disease

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    Free radicals may be involved in the aetiology of cancer and cardiovascular diseases. In epidemiological studies poor plasma levels of all essential antioxidants are associated with increased relative risks; in particular, low levels of carotene and vitamin E with the risk of cancer and ischemic heart disease, respectively. The studies suggest that for optimal synergistic protection the plasma antioxidant levels should simultaneously exceed the threshold values of 28-30 μmol/l lipid-standardized vitamin E, 40-50 μmol/l vitamin C, 0.4-0.5 (μmol/l carotene and 2.2-2.8 μmol/l lipid-standardized vitamin A. However the preventive efficacy of an optional antioxidant status is still to be proven in randomized intervention trials. Although these antioxidant micronutrients may be the primary protective components of vegetable-rich ‘preventive' diets, the potentials of other plant components await exploration, eg carotenoids other than β-carotene, bioflavonoids and oxygen-sensitive B-vitamin

    University of Twente at GeoCLEF 2006: Geofiltered Document Retrieval

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    An evaluation resource for geographic information retrieval

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    In this paper we present an evaluation resource for geographic information retrieval developed within the Cross Language Evaluation Forum (CLEF). The GeoCLEF track is dedicated to the evaluation of geographic information retrieval systems. The resource encompasses more than 600,000 documents, 75 topics so far, and more than 100,000 relevance judgments for these topics. Geographic information retrieval requires an evaluation resource which represents realistic information needs and which is geographically challenging. Some experimental results and analysis are reported

    GeoCLEF 2007: the CLEF 2007 cross-language geographic information retrieval track overview

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    GeoCLEF ran as a regular track for the second time within the Cross Language Evaluation Forum (CLEF) 2007. The purpose of GeoCLEF is to test and evaluate cross-language geographic information retrieval (GIR): retrieval for topics with a geographic specification. GeoCLEF 2007 consisted of two sub tasks. A search task ran for the third time and a query classification task was organized for the first. For the GeoCLEF 2007 search task, twenty-five search topics were defined by the organizing groups for searching English, German, Portuguese and Spanish document collections. All topics were translated into English, Indonesian, Portuguese, Spanish and German. Several topics in 2007 were geographically challenging. Thirteen groups submitted 108 runs. The groups used a variety of approaches. For the classification task, a query log from a search engine was provided and the groups needed to identify the queries with a geographic scope and the geographic components within the local queries

    Challenges to evaluation of multilingual geographic information retrieval in GeoCLEF

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    This is the third year of the evaluation of geographic information retrieval (GeoCLEF) within the Cross-Language Evaluation Forum (CLEF). GeoCLEF 2006 presented topics and documents in four languages (English, German, Portuguese and Spanish). After two years of evaluation we are beginning to understand the challenges to both Geographic Information Retrieval from text and of evaluation of the results of geographic information retrieval. This poster enumerates some of these challenges to evaluation and comments on the limitations encountered in the first two evaluations

    GeoCLEF 2006: the CLEF 2006 Ccross-language geographic information retrieval track overview

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    After being a pilot track in 2005, GeoCLEF advanced to be a regular track within CLEF 2006. The purpose of GeoCLEF is to test and evaluate cross-language geographic information retrieval (GIR): retrieval for topics with a geographic specification. For GeoCLEF 2006, twenty-five search topics were defined by the organizing groups for searching English, German, Portuguese and Spanish document collections. Topics were translated into English, German, Portuguese, Spanish and Japanese. Several topics in 2006 were significantly more geographically challenging than in 2005. Seventeen groups submitted 149 runs (up from eleven groups and 117 runs in GeoCLEF 2005). The groups used a variety of approaches, including geographic bounding boxes, named entity extraction and external knowledge bases (geographic thesauri and ontologies and gazetteers)
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