Bimodal adaptive hypermedia and interactive multimedia a web-based learning environment based on Kolb's theory of learning style

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Vers l'installation d'un espace musical : ethnographie de la scène punk à Montréal

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Interactive effects of ocean acidification and nitrogen limitation on the diatom Phaeodactylum tricornutum

Climate change is expected to bring about alterations in the marine physical and chemical environment that will induce changes in the concentration of dissolved CO2 and in nutrient availability. These in turn are expected to affect the physiological performance of phytoplankton. In order to learn how phytoplankton respond to the predicted scenario of increased CO2 and decreased nitrogen in the surface mixed layer, we investigated the diatom Phaeodactylum tricornutum as a model organism. The cells were cultured in both low CO2 (390 µatm) and high CO2 (1000 µatm) conditions at limiting (10 µmol/L) or enriched (110 µmol/L) nitrate concentrations. Our study shows that nitrogen limitation resulted in significant decreases in cell size, pigmentation, growth rate and effective quantum yield of Phaeodactylum tricornutum, but these parameters were not affected by enhanced dissolved CO2 and lowered pH. However, increased CO2 concentration induced higher rETRmax and higher dark respiration rates and decreased the CO2 or dissolved inorganic carbon (DIC) affinity for electron transfer (shown by higher values for K1/2 DIC or K1/2 CO2). Furthermore, the elemental stoichiometry (carbon to nitrogen ratio) was raised under high CO2 conditions in both nitrogen limited and nitrogen replete conditions, with the ratio in the high CO2 and low nitrate grown cells being higher by 45% compared to that in the low CO2 and nitrate replete grown ones. Our results suggest that while nitrogen limitation had a greater effect than ocean acidification, the combined effects of both factors could act synergistically to affect marine diatoms and related biogeochemical cycles in future oceans.

Interactive effects of ocean acidification and neighboring corals on the growth of Pocillopora verrucosa

The physical and chemical environment around corals, as well as their physiology, can be affected by interactions with neighboring corals. This study employed small colonies (4 cm diameter) of Pocillopora verrucosa and Acropora hyacinthus configured in spatial arrays at 7 cm/s flow speed to test the hypothesis that ocean acidification (OA) alters interactions among them. Interaction effects were quantified for P. verrucosa using three measures of growth: calcification (i.e., weight), horizontal growth, and vertical growth. The study was carried out in May-June 2014 using corals from 10 m depth on the outer reef of Moorea, French Polynesia. Colonies of P. verrucosa were placed next to conspecifics or heterospecifics (A. hyacinthus) in arrangements of two or four colonies (pairs and aggregates) that were incubated at ambient and high pCO2 (1000 µatm) for 28 days. There was an effect of pCO2, and arrangement type on multivariate growth (utilizing the three measures of growth), but no interaction between the main effects. Conversely, arrangement and pCO2 had an interactive effect on calcification, with an overall 23 % depression at high pCO2 versus ambient pCO2 (i.e., pooled among arrangements). Within arrangements, there was a 34-45 % decrease in calcification for solitary and paired conspecifics, but no effect in conspecific aggregates, heterospecific pairs, or heterospecific aggregates. Horizontal growth was negatively affected by pCO2 and arrangement type, while vertical growth was positively affected by arrangement type. Together, our results show that conspecific aggregations can mitigate the negative effects of OA on calcification of colonies within an aggregation.

An Interactive Model to Teach Motor Skills

There has been a tremendous increase in our knowledge of hum motor performance over the last few decades. Our theoretical understanding of how an individual learns to move is sophisticated and complex. It is difficult however to relate much of this information in practical terms to physical educators, coaches, and therapists concerned with the learning of motor skills (Shumway-Cook & Woolcott, 1995). Much of our knowledge stems from lab testing which often appears to bear little relation to real-life situations. This lack of ecological validity has slowed the flow of information from the theorists and researchers to the practitioners. This paper is concerned with taking some small aspects of motor learning theory, unifying them, and presenting them in a usable fashion. The intention is not to present a recipe for teaching motor skills, but to present a framework from which solutions can be found. If motor performance research has taught us anything, it is that every individual and situation presents unique challenges. By increasing our ability to conceptualize the learning situation we should be able to develop more flexible and adaptive responses to the challege of teaching motor skills. The model presented here allows a teacher, coach, or therapist to use readily available observations and known characteristics about a motor task and to conceptualize them in a manner which allows them to make appropriate teaching/learning decisions.