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.

Hot spots and pseudogaps for hole- and electron-doped high-temperature superconductors.

Abstract: Using cluster perturbation theory, it is shown that the spectral weight and pseudogap observed at the Fermi energy in recent angle resolved photoemission spectroscopy of both electron- and hole-doped high-temperature superconductors find their natural explanation within the $t\mathrm{\text{\ensuremath{-}}}{t}^{\ensuremath{'}}\mathrm{\text{\ensuremath{-}}}{t}^{\ensuremath{'}\ensuremath{'}}\mathrm{\text{\ensuremath{-}}}U$ Hubbard model in two dimensions. The value of the interaction $U$ needed to explain the experiments for electron-doped systems at optimal doping is in the weak to intermediate coupling regime where the $t\mathrm{\text{\ensuremath{-}}}J$ model is inappropriate. At strong coupling, short-range correlations suffice to create a pseudogap, but at weak-coupling long correlation lengths associated with the antiferromagnetic wave vector are necessary.

Chemical basis of DNA sugar-phosphate cleavage by low-energy electrons.

Abstract: DNA damage by low-energy electrons (LEE) was examined using a novel system in which thin solid films of oligonucleotide tetramers (CGTA and GCAT) were irradiated with monoenergetic electrons (10 eV) under ultrahigh vacuum. The products of irradiation were examined by HPLC. These analyses permitted the quantitation of 16 nonmodified nucleobase, nucleoside, and nucleotide fragments of each tetramer resulting from the cleavage of phosphodiester and N-glycosidic bonds. The distribution of nonmodified products suggests a mechanism of damage involving initial electron attachment to nucleobase moieties, followed by electron transfer to the sugar−phosphate backbone, and subsequent dissociation of the phosphodiester bond. Moreover, virtually all the nonmodified fragments contained a terminal phosphate group at the site of cleavage. These results demonstrate that the phosphodiester bond breaks by a distinct pathway in which the negative charge localizes on the phosphodiester bond giving rise to nonmodified fragment...

The rising prevalence of prescription opioid injection and its association with hepatitis C incidence among street-drug users.

Abstract: Ce manuscrit est une pre-publication d'un article paru dans Addiction 2012; 107(7): 1318-1327 url: http://www.addictionjournal.org/

Foraging Distances and Home Range of Pregnant and Lactating Little Brown Bats (Myotis Lucifugus)

Abstract: As income breeders, lactating female bats rely on current resource intake to support costs of reproduction and so must reconcile the conflicting demands of foraging and nursing. We documented changes in the movement of female little brown bats (Myotis lucifugus) around roosts between pregnancy and lactation. Home-range size dropped by 51% between pregnancy and lactation, resulting in a 35% decrease in flight distances. Although pregnant females rarely returned to roosts during the night, lactating females returned 1–2 times, which led to an increase in activity at the roosts beginning about 3 h after initial emergence. We argue that their high mass-specific milk production forces lactating females to nurse at night, which in turn imposes a constraint on foraging distances. The shift to a smaller home range is probably facilitated by the concomitant increase in insect biomass during the July lactation period.