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.

Cell cycle-regulated generation of single-stranded G-rich DNA in the absence of telomerase

Abstract: Current models of telomere replication predict that due to the properties of the polymerases implicated in semiconservative replication of linear DNA, the two daughter molecules have one end that is blunt and one end with a short 3′ overhang. Telomerase is thought to extend the short 3′ overhang to produce long single-stranded overhangs. Recently, such overhangs, or TG 1–3 tails, were shown to occur on both telomeres of replicated linear plasmids in yeast. Moreover, indirect evidence suggested that the TG 1–3 tails also occurred in a yeast strain lacking telomerase. We report herein a novel in-gel hybridization technique to probe telomeres for single-stranded DNA. Using this method, it is shown directly that in yeast strains lacking the TLC1 gene encoding the yeast telomerase RNA, TG 1–3 single-stranded DNA was generated on chromosomal and plasmid telomeres. The single-stranded DNA only appeared in S phase and was sensitive to digestion with a single-strand-specific exonuclease. These data demonstrate that during replication of telomeres, TG 1–3 tails can be generated in a way that is independent of telomerase-mediated strand elongation. In wild-type strains, these TG 1–3 tails could subsequently serve as substrates for telomerase and telomere binding proteins on all telomeres.

Two-qubit gate of combined single-spin rotation and interdot spin exchange in a double quantum dot.

Abstract: A crucial requirement for quantum-information processing is the realization of multiple-qubit quantum gates. Here, we demonstrate an electron spin-based all-electrical two-qubit gate consisting of single-spin rotations and interdot spin exchange in a double quantum dot. A partially entangled output state is obtained by the application of the two-qubit gate to an initial, uncorrelated state. We find that the degree of entanglement is controllable by the exchange operation time. The approach represents a key step towards the realization of universal multiple-qubit gates.

Effects of density and weather on survival of bighorn sheep lambs ( Ovis canadensis )

Abstract: Density-dependence in juvenile survival may be difficult to detect if survival is also affected by density-independent factors. We investigated the relationships among weather parameters, population density, and lamb survival of bighorn sheep with long-term data from a marked population where we manipulated population density. We distinguished neonatal survival and winter survival. Density interacted with weather variables to affect neonatal survival; spring and winter temperatures had a positive effect on neonatal survival only when population density was high. Neonatal survival was positively affected by spring precipitation independently of population density. Winter survival was positively correlated with temperature and precipitation during the previous spring, negatively correlated with density, and independent of winter temperature or snowfall. The effect of weather on lamb winter survival did not vary with density. Bighorn lambs are well adapted to harsh winter weather, but spring weather influenced survival of lambs at birth and during the subsequent winter, possibly through its effects on forage availability. Our study clearly demonstrates density-dependence in lamb survival. Some of the effects of weather on lamb survival are density-independent, others are mediated by an interaction with population density.

Distortion-dependent Raman spectra and mode mixing in R MnO 3 perovskites ( R = La , Pr , Nd , Sm , Eu , Gd , Tb , Dy , Ho , Y )

Abstract: The polarized Raman spectra of orthorhombic $R{\mathrm{MnO}}_{3}$ series $(R=\mathrm{La},\mathrm{Pr},\mathrm{Nd},\mathrm{Sm},\mathrm{Eu},\mathrm{Gd},\mathrm{Tb},\mathrm{Dy},\mathrm{Ho},\mathrm{Y})$ were studied at room temperature. The variation of phonon frequencies with $R$ ionic radius ${r}_{R}$ as a whole confirms the commonly accepted Raman line assignments with two noticeable exceptions: (1) with decreasing ${r}_{R}$ the stretching ${A}_{g}(1)$ and bending ${A}_{g}(3)$ modes strongly mix for $R=\mathrm{Sm}$ to Tb, while for further decrease or ${r}_{R}$ $(R=\mathrm{Dy},\mathrm{Ho},\mathrm{Y})$ the ${A}_{g}(3)$ mode is observed at higher frequency than ${A}_{g}(1)$ mode; (2) similar distortion-dependent mode mixing takes place for the rotational ${A}_{g}(2)$ and $\mathrm{O}1(x)$ $[{A}_{g}(7)]$ modes. The mode mixing is particularly strong for the $R{\mathrm{MnO}}_{3}$ compounds with ${r}_{R}$ values close to the transition from $A$ type to incommensurate sinusoidal antiferromagnetic ordering at low temperatures. The frequency of rotational ${A}_{g}(2)$ and ${A}_{g}(4)$ modes scales to the angles of ${\mathrm{MnO}}_{6}$ $[101]$ and $[010]$ rotations, respectively, and could be used as a measure of their value.

Multimorbidity is common to family practice: Is it commonly researched?

Abstract: OBJECTIVE Family physicians often have to care for patients with several concurrent chronic conditions (multimorbidity or comorbidity). Consequently, they need to inform themselves by reading indexed publications on multimorbidity. This study aimed to assess how well the concept of multimorbidity was covered in the medical literature. Objectives were first, to quantify the literature on multimorbidity (or comorbidity) and to compare the number of publications on it with the number of publications on three common chronic conditions (asthma, hypertension, and diabetes), and second, to describe the articles on multimorbidity. DESIGN Bibliometric study. METHOD We consulted MEDLINE for the reference period 1990 to the end of 2002. The term “multimorbidity” and its various spellings was used as the search term. Comorbidity, asthma, hypertension, and diabetes were searched for using their respective MeSH terms. For comparison purposes, prevalence data were taken from published sources.