993 resultados para GIS web


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Science-based approaches to support the conservation of marine biodiversity have been developed in recent years. They include measures of ‘rarity’, ‘diversity’, ‘importance’, biological indicators of water ‘quality’ and measures of ‘sensitivity’. Identifying the sensitivity of species and biotopes, the main topic of this contribution, relies on accessing and interpreting available scientific data in a structured way and then making use of information technology to disseminate suitably presented information to decision makers. The Marine Life Information Network (MarLIN) has achieved that research for a range of environmentally critical species and biotopes over the past four years and has published the reviews on the MarLIN Web site (www.marlin.ac.uk). Now, by linking the sensitivity database and databases of survey information, sensitivity mapping approaches using GIS are being developed. The methods used to assess sensitivity are described and the approach is advocated for wider application in Europe.

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Se analizan y describen las principales líneas de trabajo de la Web Semántica en el ámbito de los archivos de televisión. Para ello, se analiza y contextualiza la web semántica desde una perspectiva general para posteriormente analizar las principales iniciativas que trabajan con lo audiovisual: Proyecto MuNCH, Proyecto S5T, Semantic Television y VideoActive.

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Many metals have serious toxic effects when ingested by aquatic organisms, and the process of bioaccumulation intensifies this problem. A better understanding of bioaccumulation trends of anthropogenically introduced metals in freshwater food webs is necessary for the development of effective management strategies to protect aquatic organisms, as well as organisms (including humans) that consume top-predator fish in these food webs. Various fish species representing different trophic levels of a pelagic food chain were sampled from Lake Champlain (VT/NY). Atomic absorption spectrometry (AAS) was used to determine levels of chromium, copper, cobalt, cadmium, lead, zinc, nickel, rubidium, cesium and potassium in the fish samples. Metal concentrations for chromium, cobalt, nickel, cesium, cadmium (<5.0 ppm) and lead (<10.0 ppm) were found to be all below detection limits. Carbon and nitrogen isotopic ratios were analyzed to determine the trophic relationship of each fish species. Stable isotope and AAS metal data were used in tandem to produce linear regressions for each metal against trophic level to assess biomagnification. Both potassium and zinc showed no biomagnification because they are homeostatically regulated essential trace metals. Copper was under the detection limits for all fish species with the exception of the sea lamprey; but showed a significant biodiminution among the invertebrates and lamprey. Rubidium, a rarely studied metal, was shown to increase with trophic level in a marginally significant linear relationship suggesting biomagnification is possible where more trophic levels are sampled.

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Historical GIS has the potential to re-invigorate our use of statistics from historical censuses and related sources. In particular, areal interpolation can be used to create long-run time-series of spatially detailed data that will enable us to enhance significantly our understanding of geographical change over periods of a century or more. The difficulty with areal interpolation, however, is that the data that it generates are estimates which will inevitably contain some error. This paper describes a technique that allows the automated identification of possible errors at the level of the individual data values.

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