François Guillemette

A New Incubator for the Assessment of Hatching and Emergence Success as Well as the Timing of Emergence in Salmonids

Abstract We devised a new incubator to estimate hatching and emergence success as well as the timing of emergence of brook trout Salvelinus fontinalis. The incubation basket is cylindrical and made of a polyvinyl chloride (PVC) grid that allows water to flow through from all directions. A fry trap is set on top of the incubation basket to catch the emergent larvae. A PVC coupler is fixed to the incubation basket and allows the fry trap to be easily removed and replaced so that one can sample larvae during emergence. In the field, the emergence success for incubators containing natural substrate ranged from 0% to 50%, compared with 0% to 77% for incubators that used Astroturf as a substrate. In the laboratory, the emergence success with Astroturf alone (75%) was comparable to that in the incubators that used Astroturf in the field (73%), suggesting that the incubator structure itself does not influence the survival of brook trout eggs. This incubator is easy to build and the materials needed for its constr...

Temporal Dynamics in the Concentration, Flux, and Optical Properties of Tree‐Derived Dissolved Organic Matter in an Epiphyte‐Laden Oak‐Cedar Forest

Studies on the fate and transport of dissolved organic matter (DOM) along the rainfall-to-discharge flow pathway typically begin in streams or soils, neglecting the initial enrichment of rainfall with DOM during contact with plant canopies. However, rain water can gather significant amounts of tree-derived DOM (tree-DOM) when it drains from the canopy, as throughfall, and down the stem, as stemflow. We examined the temporal variability of event-scale tree-DOM concentrations, yield, and optical (light absorbance and fluorescence) characteristics from an epiphyte-laden Quercus virginiana-Juniperus virginiana forest on Skidaway Island, Savannah, Georgia (USA). All tree-DOM fluxes were highly enriched in dissolved organic carbon (DOC) compared to rainfall, and epiphytes further increased concentrations. Stemflow DOC concentrations were greater than throughfall across study species, yet larger throughfall water yields produced greater DOC yields versus stemflow. Tree-DOM optical characteristics indicate it is aromatic-rich with fluorescent DOM (FDOM) dominated by humic-like fluorescence, containing 10-20% protein-like (tryptophan-like) fluorescence. Storm size was the only storm condition that strongly correlated with tree-DOM concentration and flux; however, throughfall and stemflow optical characteristics varied little across a wide range of storm conditions (from low magnitude events to intense tropical storms). Annual tree-DOM yields from the study forest (0.8-46 g-C m-2 yr-1) were similar to other yields from discrete down-gradient fluxes (litter leachates, soil leachates, and stream discharge) along the rainfall-to-discharge flow path.

Competency-based Education and Practical Training: Document Analysis and Critique

Dans la premiere generation d’APC, le concept de competence est lie aux concepts de comportement, pratique, performance et action (Gage & Winne, 1975; Hamilton, 1973; Hilbert, 1982; Howsam & Houston, 1972; Joyce, 1974; Leonard & Utz, 1974; Schostak, 1996; Spady, 1977; Tomlinson, 1995; Woodruffe, 1992). Sur le plan conceptuel, cette definition s’oppose a la perspective dichotomique inspiree de Chomsky (1957). Pour ce dernier, d’une part, la competence est un potentiel d’action et non l’action comme telle; d’autre part, l’action qui actualise le potentiel-competence est une performance.