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.

Practical characterization of quantum devices without tomography.

Abstract: Quantum tomography is the main method used to assess the quality of quantum information processing devices. However, the amount of resources needed for quantum tomography is exponential in the device size. Part of the problem is that tomography generates much more information than is usually sought. Taking a more targeted approach, we develop schemes that enable (i) estimating the fidelity of an experiment to a theoretical ideal description, (ii) learning which description within a reduced subset best matches the experimental data. Both these approaches yield a significant reduction in resources compared to tomography. In particular, we demonstrate that fidelity can be estimated from a number of simple experiments that is independent of the system size, removing an important roadblock for the experimental study of larger quantum information processing units.

Universal T -linear resistivity and Planckian dissipation in overdoped cuprates

Abstract: The perfectly linear temperature dependence of the electrical resistivity observed as T → 0 in a variety of metals close to a quantum critical point1–4 is a major puzzle of condensed-matter physics5. Here we show that T-linear resistivity as T → 0 is a generic property of cuprates, associated with a universal scattering rate. We measured the low-temperature resistivity of the bilayer cuprate Bi2Sr2CaCu2O8+δ and found that it exhibits a T-linear dependence with the same slope as in the single-layer cuprates Bi2Sr2CuO6+δ (ref. 6), La1.6−xNd0.4SrxCuO4 (ref. 7) and La2−xSrxCuO4 (ref. 8), despite their very different Fermi surfaces and structural, superconducting and magnetic properties. We then show that the T-linear coefficient (per CuO2 plane), A1□, is given by the universal relation A1□TF = h/2e2, where e is the electron charge, h is the Planck constant and TF is the Fermi temperature. This relation, obtained by assuming that the scattering rate 1/τ of charge carriers reaches the Planckian limit9,10, whereby ħ/τ = kBT, works not only for hole-doped cuprates6–8,11,12 but also for electron-doped cuprates13,14, despite the different nature of their quantum critical point and strength of their electron correlations. A transport study of overdoped cuprates reveals a resistivity that is linear as the temperature approaches 0 K, and is associated with a universal scattering rate.

Eleven Telomere, Epigenetic Clock, and Biomarker-Composite Quantifications of Biological Aging: Do They Measure the Same Thing?

Abstract: The geroscience hypothesis posits that therapies to slow biological processes of aging can prevent disease and extend healthy years of life. To test such "geroprotective" therapies in humans, outcome measures are needed that can assess extension of disease-free life span. This need has spurred development of different methods to quantify biological aging. But different methods have not been systematically compared in the same humans. We implemented 7 methods to quantify biological aging using repeated-measures physiological and genomic data in 964 middle-aged humans in the Dunedin Study (New Zealand; persons born 1972-1973). We studied 11 measures in total: telomere-length and erosion, 3 epigenetic-clocks and their ticking rates, and 3 biomarker-composites. Contrary to expectation, we found low agreement between different measures of biological aging. We next compared associations between biological aging measures and outcomes that geroprotective therapies seek to modify: physical functioning, cognitive decline, and subjective signs of aging, including aged facial appearance. The 71-cytosine-phosphate-guanine epigenetic clock and biomarker composites were consistently related to these aging-related outcomes. However, effect sizes were modest. Results suggested that various proposed approaches to quantifying biological aging may not measure the same aspects of the aging process. Further systematic evaluation and refinement of measures of biological aging is needed to furnish outcomes for geroprotector trials.

Prevalence of primary dysmenorrhea in Canada.

Abstract: Objective: The aim of this study was to describe the prevalence, clinical effect, characteristics, and underlying risk factors of primary dysmenorrhea PD in Canada. Methods: A stratified, random sample of 2721 women 18 Years and older was identified, and the women were interviewed by telephone. Data about menstrual symptoms and patterns and socio-demographic factors were obtained. The frequency, severity, and effect of menstrual pain were quantified. Logistic regression analysis was performed in order to identify independent risk factors for PD. Results: In the sample, 1546 women were having menstrual periods; of these, 934 (60%) met the criteria for PD. Sixty percent of the women with PD described their pain as moderate or severe. Fifty-one percent reported that their activities had been limited, and 17% reported missing school or work because of PD. The prevalence of PD decreased with increasing age ( P P = 0.002). Users of oral contraceptives OCs tended to have less pain than non-users ( P = 0.005). Socio-economic status, nulliparity, and earlier age at menarche were not independently associated with PD. However, nulliparous women, smokers, and women not using OCs were more likely to report disabling symptoms. Conclusions: The majority of Canadian women will suffer from dysmenorrhea at some time during their reproductive years. Available prescription treatments are underused. Young age, smoking, and non-use of OCs are independent risk factors for PD.

The Remarkable Underlying Ground States of Cuprate Superconductors

Abstract: Cuprates exhibit exceptionally strong superconductivity. To understand why, it is essential to elucidate the nature of the electronic interactions that cause pairing. Superconductivity occurs on th...