Université de Montréal

About: Université de Montréal is a education organization based out in Montreal, Quebec, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 45641 authors who have published 100476 publications receiving 4004007 citations. The organization is also known as: University of Montreal & UdeM.

Deep learning of representations for unsupervised and transfer learning

Abstract: Deep learning algorithms seek to exploit the unknown structure in the input distribution in order to discover good representations, often at multiple levels, with higher-level learned features defined in terms of lower-level features The objective is to make these higher-level representations more abstract, with their individual features more invariant to most of the variations that are typically present in the training distribution, while collectively preserving as much as possible of the information in the input Ideally, we would like these representations to disentangle the unknown factors of variation that underlie the training distribution Such unsupervised learning of representations can be exploited usefully under the hypothesis that the input distribution P(x) is structurally related to some task of interest, say predicting P(y/x) This paper focuses on the context of the Unsupervised and Transfer Learning Challenge, on why unsupervised pre-training of representations can be useful, and how it can be exploited in the transfer learning scenario, where we care about predictions on examples that are not from the same distribution as the training distribution

Beta diversity as the variance of community data: dissimilarity coefficients and partitioning.

Abstract: Beta diversity can be measured in different ways. Among these, the total variance of the community data table Y can be used as an estimate of beta diversity. We show how the total variance of Y can be calculated either directly or through a dissimilarity matrix obtained using any dissimilarity index deemed appropriate for pairwise comparisons of community composition data. We addressed the question of which index to use by coding 16 indices using 14 properties that are necessary for beta assessment, comparability among data sets, sampling issues and ordination. Our comparison analysis classified the coefficients under study into five types, three of which are appropriate for beta diversity assessment. Our approach links the concept of beta diversity with the analysis of community data by commonly used methods like ordination and anova. Total beta can be partitioned into Species Contributions (SCBD: degree of variation of individual species across the study area) and Local Contributions (LCBD: comparative indicators of the ecological uniqueness of the sites) to Beta Diversity. Moreover, total beta can be broken up into within- and among-group components by manova, into orthogonal axes by ordination, into spatial scales by eigenfunction analysis or among explanatory data sets by variation partitioning.

Endovascular Treatment of Unruptured Aneurysms

Abstract: Background and Purpose— We sought to better define the morbidity of endovascular Guglielmi detachable coil (GDC) treatment of unruptured cerebral aneurysms and to discuss its role in the prevention of subarachnoid hemorrhage. Methods— We conducted an observational study from August 1992 to June 1999 of 125 unruptured aneurysms treated with GDC in 116 patients: 91 women (78.4%) and 25 men (21.6%), aged 30 to 78 years (mean age, 50.6 years). Immediate and late clinical results were recorded for any neurological event or hemorrhage related to the treated unruptured aneurysm. Angiographic results are reported as immediate, early (2 to 12 months), intermediate (12 to 30 months), and late follow-up (>30 months). Results— Immediate angiographic results showed complete obliteration (class 1) in 59 (47.2%) or residual neck (class 2) in 53 aneurysms (42.4%), leaving 6 residual aneurysms (4.8%) and 7 failures (5.6%). Early follow-up angiograms, available in 100 treated aneurysms (84%), revealed class 1 in 52% and cl...

Meta-analysis identifies 13 new loci associated with waist-hip ratio and reveals sexual dimorphism in the genetic basis of fat distribution

Abstract: Waist-hip ratio (WHR) is a measure of body fat distribution and a predictor of metabolic consequences independent of overall adiposity. WHR is heritable, but few genetic variants influencing this trait have been identified. We conducted a meta-analysis of 32 genome-wide association studies for WHR adjusted for body mass index (comprising up to 77,167 participants), following up 16 loci in an additional 29 studies (comprising up to 113,636 subjects). We identified 13 new loci in or near RSPO3, VEGFA, TBX15-WARS2, NFE2L3, GRB14, DNM3-PIGC, ITPR2-SSPN, LY86, HOXC13, ADAMTS9, ZNRF3-KREMEN1, NISCH-STAB1 and CPEB4 (P = 1.9 × 10⁻⁹ to P = 1.8 × 10⁻⁴⁰) and the known signal at LYPLAL1. Seven of these loci exhibited marked sexual dimorphism, all with a stronger effect on WHR in women than men (P for sex difference = 1.9 × 10⁻³ to P = 1.2 × 10⁻¹³). These findings provide evidence for multiple loci that modulate body fat distribution independent of overall adiposity and reveal strong gene-by-sex interactions.

Reactive Oxygen Species, Vascular Oxidative Stress, and Redox Signaling in Hypertension What Is the Clinical Significance?

Abstract: Metabolism of oxygen by cells generates potentially deleterious reactive oxygen species (ROS). Under normal conditions the rate and magnitude of oxidant formation is balanced by the rate of oxidant elimination. However, an imbalance between prooxidants and antioxidants results in oxidative stress, which is the pathogenic outcome of oxidant overproduction that overwhelms the cellular antioxidant capacity. The kidney and vasculature are rich sources of NADPH oxidase-derived ROS, which under pathological conditions play an important role in renal dysfunction and vascular damage. Strong experimental evidence indicates that increased oxidative stress and associated oxidative damage are mediators of renovascular injury in cardiovascular pathologies. Increased production of superoxide anion and hydrogen peroxide, reduced nitric oxide synthesis, and decreased bioavailability of antioxidants have been demonstrated in experimental and human hypertension. These findings have evoked considerable interest because of the possibilities that therapies targeted against free radicals by decreasing ROS generation or by increasing nitric oxide availability and antioxidants may be useful in minimizing vascular injury and renal dysfunction and thereby prevent or regress hypertensive end-organ damage. This article highlights current developments in the field of ROS and hypertension, focusing specifically on the role of oxidative stress in hypertension-associated vascular damage. In addition, recent clinical trials investigating cardiovascular benefits of antioxidants are discussed, and some explanations for the rather disappointing results from these studies are addressed. Finally, important avenues for future research in the field of ROS, oxidative stress, and redox signaling in hypertension are considered.