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.

L’analyse par théorisation ancrée

Abstract: Cet article presente en detail les etapes d’une methode d’analyse qualitative, l’analyse par theorisation ancree, qui est une adaptation-transformation de la grounded theory approach. La methode permet de theoriser un phenomene empirique a travers la codification, la categorisation, la mise en relation, l’integration, la modelisation et la theorisation. La presentation de la methode est illustree par des exemples de recherches menees par l’auteur.

Anaesthesia for hip fracture surgery in adults

Abstract: Background The majority of people with hip fracture are treated surgically, requiring anaesthesia Objectives To compare different types of anaesthesia for surgical repair of hip fractures (proximal femoral fractures) in adults Search methods We searched the Cochrane Bone, Joint and Muscle Trauma Group specialised register (November 2003), MEDLINE (1996 to February week 2 2004), EMBASE (1988 to 2004 week 10) and reference lists of relevant articles Selection criteria Randomised and quasi-randomised trials comparing different methods of anaesthesia for hip fracture surgery in adults The primary focus of this review was the comparison of regional (spinal or epidural) anaesthesia versus general anaesthesia The use of nerve blocks preoperatively or in conjunction with general anaesthesia is evaluated in another review The primary outcome was mortality Data collection and analysis Two reviewers independently assessed trial quality and extracted data Main results Twenty two trials, involving 2567 predominantly female and elderly patients, comparing regional anaesthesia with general anaesthesia were included All trials had methodological flaws and many do not reflect current anaesthetic practice Pooled results from eight trials showed regional anaesthesia to be associated with a decreased mortality at one month (56/811 (69%) versus 86/857 (100%)); however, this was of borderline statistical significance (relative risk (RR) 069, 95% confidence interval (CI) 050 to 095) The results from six trials for three month mortality were not statistically significant, although the confidence interval does not exclude the possibility of a clinically relevant reduction (86/726 (118%) versus 98/765 (128%), RR 092, 95% CI 071 to 121) The reduced numbers of trial participants at one year, coming exclusively from two trials, preclude any useful conclusions for long-term mortality (80/354 (226%) versus 78/372 (210%), RR 107, 95% CI 082 to 141) Regional anaesthesia was associated with a reduced risk of deep venous thrombosis (39/129 (30%) versus 61/130 (47%); RR 064, 95% CI 048 to 086) However, this finding is insecure due to possible selection bias in the subgroups in whom this outcome was measured Regional anaesthesia was also associated with a reduced risk of acute postoperative confusion (11/117 (94%) versus 23/120 (192%), RR 050, 95% CI 026 to 095) There was insufficient evidence to draw any conclusions from a further four included trials, involving a total of 179 participants, which compared other methods of anaesthesia (a 'light' general with spinal anaesthesia; intravenous ketamine; nerve blocks) Authors' conclusions Overall, there was insufficient evidence available from trials comparing regional versus general anaesthesia to rule out clinically important differences Regional anaesthesia may reduce acute postoperative confusion but no conclusions can be drawn for mortality or other outcomes

Broken rotational symmetry in the pseudogap phase of a high- T c superconductor

Abstract: The nature of the pseudogap phase is a central problem in the effort to understand the high-transition-temperature (high-T(c)) copper oxide superconductors. A fundamental question is what symmetries are broken when the pseudogap phase sets in, which occurs when the temperature decreases below a value T*. There is evidence from measurements of both polarized neutron diffraction and the polar Kerr effect that time-reversal symmetry is broken, but at temperatures that differ significantly from one another. Broken rotational symmetry was detected from both resistivity measurements and inelastic neutron scattering at low doping, and from scanning tunnelling spectroscopy at low temperature, but showed no clear relation to T*. Here we report the observation of a large in-plane anisotropy of the Nernst effect in YBa(2)Cu(3)O(y) that sets in precisely at T* throughout the doping phase diagram. We show that the CuO chains of the orthorhombic lattice are not responsible for this anisotropy, which is therefore an intrinsic property of the CuO(2) planes. We conclude that the pseudogap phase is an electronic state that strongly breaks four-fold rotational symmetry. This narrows the range of possible states considerably, pointing to stripe or nematic order.

The balanced‐growth hypothesis and the allometry of leaf and root biomass allocation

Abstract: Summary 1. Many ecological models of plant growth assume balanced growth: that biomass is allocated preferentially to leaves or roots to increase capture of the limiting external resource. An alternative explanation is based on nonlinear (allometric) allocation as a function of plant size. The objective of this study was to test between these two alternative explanations. 2. A total of 1150 plants from 22 different herbaceous species were grown in hydroponic sand culture in factorial combinations of high (1100 µmol m−2 s−1) and low (200 µmol m−2 s−1 PAR) irradiance crossed with a full-strength and a 1/6 dilution of Hoagland’s hydroponic solution. Plants were harvested at 15, 20, 25, 30 and 35 days postgermination, and dry mass was determined for leaf and root components. These data were used to test the hypotheses of balanced growth and of allometric allocation. 3. Both irradiance and nutrient supply affected the slope and intercept of the root : shoot allometry, contrary to the allometric hypothesis but in agreement with the hypothesis of balanced growth; decreased nutrient supply increased allocation to roots; and decreased irradiance increased allocation to leaves. 4. Plants allocated relatively more biomass to roots than to leaves as plants grew larger. In order for the balanced-growth hypothesis to be correct, the net rate of nutrient uptake per unit root mass must have been decreasing relative to the net rate of carbon gain per unit leaf mass. 5. We suggest two reasons why this might be the case: (i) older roots decreased their efficiency of nutrient uptake; and (ii) larger root systems more rapidly decreased the available nutrients between flushes of hydroponic solution. 6. These results support the notion of balanced growth that is found in many ecological models of plant growth.

Pathogenic implications of mutations in the tau gene in pallido-ponto-nigral degeneration and related neurodegenerative disorders linked to chromosome 17

Abstract: Pallido-ponto-nigral degeneration (PPND) is one of the most well characterized familial neurodegenerative disorders linked to chromosome 17q21-22. These hereditary disorders are known collectively as frontotemporal dementia (FTD) and parkinsonism linked to chromosome 17 (FTDP-17). Although the clinical features and associated regional variations in the neuronal loss observed in different FTDP-17 kindreds are diverse, the diagnostic lesions of FTDP-17 brains are tau-rich filaments in the cytoplasm of specific subpopulations of neurons and glial cells. The microtubule associated protein (tau) gene is located on chromosome 17q21-22. For these reasons, we investigated the possibility that PPND and other FTDP-17 syndromes might be caused by mutations in the tau gene. Two missense mutations in exon 10 of the tau gene that segregate with disease, Asn279(Lys) in the PPND kindred and Pro301(Leu) in four other FTDP-17 kindreds, were found. A third mutation was found in the intron adjacent to the 3' splice site of exon 10 in patients from another FTDP-17 family. Transcripts that contain exon 10 encode tau isoforms with four microtubule (MT)-binding repeats (4Rtau) as opposed to tau isoforms with three MT-binding repeats (3Rtau). The insoluble tau aggregates isolated from brains of patients with each mutation were analyzed by immunoblotting using tau-specific antibodies. For each of three mutations, abnormal tau with an apparent Mr of 64 and 69 was observed. The dephosphorylated material comigrated with tau isoforms containing exon 10 having four MT-binding repeats but not with 3Rtau. Thus, the brains of patients with both the missense mutations and the splice junction mutation contain aggregates of insoluble 4Rtau in filamentous inclusions, which may lead to neurodegeneration.