995 resultados para LOCAL STRESSES


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Distribution, abundance, and several population features were studied in Ensenada de La Vela (Venezuela) between 1993 and 1998 as a first step in the assessment of local fisheries of swimming crabs. Arenaeus cribrarius was the most abundant species at the marine foreshore. Callinectes danae prevailed at the estuarine location. Callinectes bocourti was the most abundant species at the offshore. Abundances of A. cribrarius and C. danae fluctuated widely and randomly. Ovigerous females were almost absent. Adults of several species were smaller than previously reported. This study suggests that fisheries based on these swimming crabs probably will be restricted to an artisanal level because abundances appear too low to support industrial exploitation.

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EXTRACT (SEE PDF FOR FULL ABSTRACT): We describe a coupled local climate/isotope model that can calculate Rayleigh-type processes of distillation and fractionation of hydrogen isotopes along individual air mass flowlines in the western United States.This climate model is an extension of that detailed earlier by Craig and Stamm (1990). ... Volumetric effects of evapotranspiration (ET) are included. The model allows sensitivity studies of the influence of ET recycling.

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EXTRACT (SEE PDF FOR FULL ABSTRACT): An empirically derived multiple linear regression model is used to relate a local-scale dependent variable (either temperature, precipitation, or surface runoff) measured at individual gauging stations to six large-scale independent variables (temperature, precipitation, surface runoff, height to the 500-mbar pressure surface, and the zonal and meridional gradient across this surface). ...The area investigated is the western United States. ... The calibration data set is from 1948 through 1988 and includes data from 268 joint temperature and precipitation stations, 152 streamflow stations (which are converted to runoff data), and 24 gridded 500-mbar pressure height nodes.