Search

J. Strom Thurmond Lake (Georgia-South Carolina) strongly stratifies during the summer, producing a temperature-dissolved oxygen “squeeze” for landlocked blueback herring Alosa aestivalis. A coupled Eulerian-Lagrangian hybrid (CEL hybrid) model was developed to improve understanding of and better predict the in-reservoir movements of blueback herring in response to these limiting conditions. An existing application of CE-QUAL-W2, a two-dimensional, laterally averaged water quality and hydrodynamic model, was used to simulate the spatial and temporal dynamics of summer water temperature, dissolved oxygen, and hydraulics. The biological module was parameterized by using mobile hydroacoustic survey data supplemented with species composition data from gill-net surveys. The simulation accurately described the longitudinal (r 2 = 0.67) and vertical (r 2 = 0.93) distributions observed for blueback herring. The model results suggest that the longitudinal distribution of blueback herring in summer is best ...

The photophysical properties of pyrazolotriazole azomethine dyes have been investigated using both picosecond and nanosecond flash photolysis. On nanosecond timescales, prompt formation of a photoisomer is observed, the rate of decay of which shows a solvent dependence. In the presence of a triplet sensitiser a triplet pathway to the photoisomer has been established, the yield of isomer from the triplet state being considerably higher than from direct excitation. On picosecond timescales, two transients are observed; the first has a very short, solvent-independent lifetime, while the second has a longer solvent-dependent lifetime. These two transients are assigned as states formed during the relaxation of the molecules along the first excited singlet and the ground-state potential-energy surfaces, respectively. Similar kinetic behaviour is observed in a high concentration, high viscosity environment designed to mimic the photographic emulsion, indicating that the photophysical relaxation pathways are still very rapid even in this type of environment.