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41.
To prevent harm to human health from degrading ecosystems, epidemiologists need useful indicators that are sensitive to those
shifts in health status that might parallel these declines. Traditional measures of health (e.g., life expectancy, infant
mortality) are intuitively linkable to effects from environmental degradation but, in fact, they do not appear to provide
early warning indications of negative ecological impacts on health. Alternative health measures, such as social well-being,
may be needed for epidemiological research. New measures must combine those factors having policy relevance, including sensitive
measures of well-being and of health, with models of those human behaviours that contribute to ecological declines. Exposure
factors (e.g., pollution) made worse by ecosystem changes (e.g., global warming) also are relevant. In addition, epidemiologists
must be able to relate health outcomes not only to the traditional base of geo-political boundaries (e.g., census tracts or
countries), but more appropriately to eco-regions (e.g., climate regions). Only then could direct comparisons of effect be
made between areas that have eco-region as the common base for defining both denominators and numerator events for rate calculations
and comparisons. In conclusion, administrative infrastructure is needed so that meaningful eco-epidemiology can be conducted.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
42.
Sean W. Campbell John C. Dixon Colin E. Thorn & Robert G. Darmody 《Geografiska Annaler: Series A, Physical Geography》2002,84(3&4):179-185
This study examines the spatial and temporal variability of chemical denudation rates in Kärkevagge, northern Sweden. The chemical flux rates within the valley are strongly influenced by the local geology. Chemical denudation rates determined for the study period are more than double those previously reported in the literature for this valley. Rates of greater than 46t km−2 a−1 were measured at the valley mouth over the course of the melt season. This difference is likely due to differences in measurement technique compared to that used by past researchers. This rate is also much higher than for other arctic and alpine watersheds. Chemical denudation in Kärkevagge is comparable to larger temperate rivers. The rapid chemical denudation in Kärkevagge is likely due to sulfide weathering creating acid solutions. 相似文献
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Robert G. Darmody Sean W. Campbell John C. Dixon & Colin E. Thorn 《Geografiska Annaler: Series A, Physical Geography》2002,84(3-4):187-192
The second marvel to catch the eye of the visitor to Kärkevagge, after the impressive boulder deposit on the floor of the valley, is the series of prominent white stripes running down the valley's dark cliffs. Streams and springs descending the eastern flank of Kärkevagge are marked by the presence of whitish coatings on the black rock surfaces and on cobbles lining ephemeral waterways. These were referred to as 'lime crusts' by early investigators, but they are not reactive to HCl. We believe that they are a precipitate resulting from acid attack on the local rocks. Pyrite is common in many of the rocks in the valley and its oxidation produces sulfuric acid. As the dissolved mineral elements are carried in the drainage water, efflorescence forms on the surfaces where the water flows due to evaporation or to changes in temperature. The exact mineralogy of the white crusts is unknown, but the crusts are dominated by Al, S, and O, and in some cases by Ca, depending on the substrate and local conditions. Gypsum, illite, and chlorite have been identified by X–ray diffraction of some scrapings of white–coated rocks. However, we believe that some unidentified oxy–hydroxy aluminum sulfates make up the bulk of the precipitates. 相似文献
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Colin Flint 《The Professional geographer》2003,55(2):162-169
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This is a web presentation of the work presented at the 10th Annual Conference of the CFD Society of Canada, “CFD 2002”, at the University of Windsor on June 9-11, 2002. This discussion paper presents the four-dimensional variational data assimilation (4D-VAR) technique as a tool to forecast floods. This discussion will be limited to hydrological forecast. We assume that the weather, here a large rainstorm, had already been forecasted by the meteorological services. In the 4D-VAR technique, we need to minimize, in the sense of Lagrange, a cost function which measures the difference between the forecast and the observations. The physical equations acts as a set of constraints. Here, the model is the shallow-water equations modified to include sediment transport. The minimum was found by using the steepest descent algorithm. This is made possible because the gradient of the cost function can be calculated analytically by using the adjoint equations of the model. To illustrate the 4D-VAR technique, the bypass of a simple theoretical dam as well as the more complex overflowing of the Chicoutimi River at the Chute-Garneau dam (during the 1996 flood) are investigated. 相似文献