Université de Sherbrooke

About: Université de Sherbrooke is a education organization based out in Sherbrooke, Quebec, Canada. It is known for research contribution in the topics: Population & Receptor. The organization has 14922 authors who have published 28783 publications receiving 792511 citations. The organization is also known as: Universite de Sherbrooke & Sherbrooke University.

Climate forcing and density dependence in a mountain ungulate population

Abstract: Population models in ecology are rarely validated by comparing their pre- dictions to long-term observations of changes in population size. We have used a variety of analytical tools to examine a 45-year time series of annual censuses of Alpine ibex (Capra ibex) in the Gran Paradiso National Park in northwestern Italy. This ibex population grew from about 3300 to almost 5000 individuals in the 1980s during a decade of anom- alously mild winters, and then began to decline in the 1990s. By 1997, the population size had returned to previous levels. Adult survival apparently increased and adult sex ratio may have changed to slightly favor males during the increase in population density. Yearly changes in total population were correlated with seasonal average snow depth and population density over the 39 years for which climate data were available. Our results show that the ibex population size was limited by both density dependence and deep snow. A model based on these factors fit to the first 19 years of data was used to forecast subsequent changes in total population based on initial population size and yearly snow depth. The model was able to predict the increase and subsequent decline in total population size over the final 20 years of the study but failed to reproduce population levels after the eruption. Our results suggest that the 1980s episode of population growth was primarily driven by increased adult survival, rather than increased recruitment.

Pozzolanic properties of fine and coarse color-mixed glass cullet

Abstract: Mixed glasses of different colors are economically difficult to reuse for the fabrication of new glass products but their use in cement-based materials is a promising way to recycle this material. This paper deals with the pozzolanic activity of mixed glass cullet, by evaluating the pozzolanic behavior of a large range of glass particle sizes, from less than 40 μm (540 m2/kg) up to 2.5 mm (2.2 m2/kg). Five different classes of glass are assessed separately, in terms of compressive strength tests on mortars, consumption of lime (TG), morphology (SEM) and composition of hydrates (EDX and X-ray fluorescence). The results show that the pozzolanic activity increases with glass fineness and that, compared to a reference material without glass, equivalent or superior compressive strength can be obtained when using up to 40% of glass of 540 m2/kg fineness. A transition fineness around 30 m2/kg (140 μm) is highlighted, for which the pozzolanic activity becomes substantial. However, a slight but significant pozzolanic activity is detected for coarse particles (>1 mm), as confirmed by the consumption of Ca(OH)2, the formation of C–S–H-like hydrates and an increase of 10% (5 MPa) in the compressive strength compared to an inert admixture. The chronology of the reaction (pozzolanic and alkali-reactive) for coarse glass particles is discussed.

CO2-Stimulated Diversiform Deformations of Polymer Assemblies

Abstract: Use of a given physiological stimulus to delicately deform polymer assemblies is a challenging topic. Here we develop synthetic block copolymers to construct a series of CO2-sensitive self-assembled nanostructures that can simulate controllable deformations of the organelles in different ways. By controlling the CO2 stimulation levels, one can modulate the size, shape, and morphology of the polymer aggregates, which is conducive to understanding the stimuli-triggered dynamic reshaping process of polymer assemblies in aqueous solution.