Fine-scale assessment of genetic diversity of trembling aspen in northwestern North America

Background: In North America, the last ice age is the most recent event with severe consequences on boreal species’ ranges. Phylogeographic patterns of range expansion in trembling aspen (Populus tremuloides) suggested that Beringia is likely to be a refugium and the "ice-free corridor" in Alberta may represent a region where small populations persisted during the last glacial maximum (LGM). The purpose of this study was to ascertain whether the origins of trembling aspen in western North America are reflected in the patterns of neutral genetic diversity and population structure. A total of 28 sites were sampled covering the northwestern part of aspen’s distribution, from Saskatchewan to Alaska. Twelve microsatellite markers were used to describe patterns of genetic diversity. The genetic structure of trembling aspen populations was assessed by using multivariate analyses, Mantel correlograms, neighbor-joining trees and Bayesian analysis. Results: Microsatellite markers revealed little to no neutral genetic structure of P. tremuloides populations in northwestern North America. Low differentiation among populations and small isolation by distance (IBD) were observed. The most probable number of clusters detected by STRUCTURE was K = 3 (?K = 5.9). The individuals in the populations of the 3 clusters share a common gene pool and showed a high level of admixture. No evidence was found that either Beringia or the "ice-free corridor" were refugia. Highest allelic richness (AR) and lowest heterozygosity (Ho) were observed in Alberta foothills of the Rocky Mountains. Conclusions: Contrary to our hypothesis, our results showed that microsatellite markers revealed little to no genetic structure in P. tremuloides populations. Consequently, no divergent populations were observed near supposed refugia. The lack of detectable refugia in Beringia and in the "ice-free corridor" was due to high levels of gene flow between trembling apsen populations. More favorable environmental conditions for sexual reproduction and successful trembling aspen seedling establishment may have contributed to increase allelic richness through recombination in populations from the Albertan foothills of the Rocky Mountains

Asservissement d'un système robotique sous-actué à un capteur neuromorphique

Le contrôle de systèmes physiques par boucle de rétroaction est intégré dans la technologie d'aujourd'hui. Ceux-ci dépendent de capteurs pour quantifier leurs interactions avec l'environnement et d'ordinateurs pour intégrer et calculer la réponse à envoyer aux actuateurs. Ce projet de recherche a pour but de prouver qu'il est possible de contrôler un système sous-actué lorsque ces composants ont été remplacés par un seul capteur neuromorphique. Pour ce faire, deux problèmes classiques de contrôle sont attaqués; le chariot-tige et le pendule de Furuta. Une approche incrémentale est empruntée pour développer une méthode de contrôle à l'aide de "reservoir computer", une méthode d'apprentissage machine à laquelle le capteur neuromorphique appartient. Le problème du chariot-tige est tout d'abord attaqué en simulation en utilisant une variante numérique d'un réservoir computer, les Echo State Network (ESN). Dans ce cadre, une méthode de recherche de réservoir est choisie et différentes configurations d'ESN ont été testées. La structure qui s'est montrée la plus efficace en simulation est un ESN simple avec une rétroaction de la dernière commande générée, arrivant à basculer le pendule et à le maintenir droit sur son axe (à l'intérieur d'une marge de +- 15 degrés) pendant en moyenne 81.2 % du temps total d'un essai. En comparaison, le contrôleur de référence maintient le pendule droit sur son axe en moyenne 85.2 % du temps d'un essai. Suite à ce succès, le contrôleur ESN est implémenté sur le montage expérimental du pendule de Furuta. Pour des essais d'une durée de 25 secondes, le contrôleur arrive à maintenir le pendule entre 15 et -15 degrés pour une durée de 31.5 % du temps total, par rapport à 62.7 % pour le contrôleur de référence utilisé sur des essais d'une même durée. Ces performances ont été atteintes avec un contrôleur ESN utilisant une rétroaction et ayant plusieurs régressions, qui correspondent à différents régimes du pendule. Finalement, ce qui a été appris est ensuite transposé au processeur et au capteur neuromorphique, pour faire des tests de contrôle avec des réservoirs physiques. En conservant la même structure de régression, le capteur neuromorphique arrive à maintenir le pendule sur sont axe pendant 18.4 % du temps d'un essai

La lecture et la virtualité de l'oeuvre littéraire : une herméneutique de la figure de l'autoréférentialité dans Pale Fire

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.[À l'origine dans / Was originally part of : Thèses et mémoires - FAS - Département de littérature comparée

An algorithmic view of gene teams

International audienc

Computing commons interval of K permutations, with applications to modular decomposition of graphs

International audienceWe introduce a new way to compute common intervals of K permutations based on a very simple and general notion of generators of common intervals. This formalism leads to simple and efficient algorithms to compute the set of all common intervals of K permutations, that can contain a quadratic number of intervals, as well as a linear space basis of this set of common intervals. Finally, we show how our results on permutations can be used for computing the modular decomposition of graphs in linear time

PReMod: a database of genome-wide mammalian cis-regulatory module predictions

We describe PReMod, a new database of genome-wide cis-regulatory module (CRM) predictions for both the human and the mouse genomes. The prediction algorithm, described previously in Blanchette et al. (2006) Genome Res., 16, 656–668, exploits the fact that many known CRMs are made of clusters of phylogenetically conserved and repeated transcription factors (TF) binding sites. Contrary to other existing databases, PReMod is not restricted to modules located proximal to genes, but in fact mostly contains distal predicted CRMs (pCRMs). Through its web interface, PReMod allows users to (i) identify pCRMs around a gene of interest; (ii) identify pCRMs that have binding sites for a given TF (or a set of TFs) or (iii) download the entire dataset for local analyses. Queries can also be refined by filtering for specific chromosomal regions, for specific regions relative to genes or for the presence of CpG islands. The output includes information about the binding sites predicted within the selected pCRMs, and a graphical display of their distribution within the pCRMs. It also provides a visual depiction of the chromosomal context of the selected pCRMs in terms of neighboring pCRMs and genes, all of which are linked to the UCSC Genome Browser and the NCBI. PReMod:

Simulation Methods for the Transient Analysis of Synchronous Alternators

The integration of unconventional renewable energy sources on the electrical grid poses challenges to the electrical engineer. This chapter focuses on the transient modeling of electrical machines. These models can be used for the design of generator control, the definition of the protection strategies, stability studies, and the evaluation of the electrical; mechanical; and thermal constraints on the machine. This chapter presents three modeling techniques: the standard d-q equivalent model, the coupled-circuit model, and the finite element model (FEM). The consideration of magnetic saturation for the different models is presented. The responses of the different models during three-phase, two-phase, and one-phase sudden short circuit are compared

Post-disaster health status of train derailment victims with posttraumatic growth

In July 2013, a train derailment causing explosions and a fire in downtown Lac-Mégantic (Municipalité Régionale de Comté du Granit, Quebec, Canada) resulted in the death of 47 people and the destruction of many homes and other buildings. This article compares the physical and psychological health of 624 adults from the Granit area exposed to this disaster three years after the tragedy, comparing based on the presence or absence of posttraumatic growth. Women, people with high levels of social support, lower levels of education, and with lower incomes were more likely to show posttraumatic growth. For psychological health, the presence of post-traumatic stress symptoms and the use of antidepressants were positively related to posttraumatic growth. Our study demonstrates that, over time, many people managed to initiate a recovery process and to see benefits from this disaster

A High Relative-Precision Color-Magnitude Diagram of M67

We have calibrated an extensive set of BVI observations of M67. We have selected stars that are most likely to be single-star members of the cluster using proper motion, radial velocity, and variability information from the literature, and an examination of the most probable color-magnitude diagram locations of unresolved stellar blends. Observations of M67 turnoff stars are a severe test of algorithms attempting to describe convective cores in the limit of small extent, and we find strong evidence of a ``hook'' just fainter than the turnoff gap. The stars in M67 support assertions that the degree of convective core overshooting decreases to zero for stars with masses in the range 1.0 < (M / M_sun) < 1.5, but that the degree of overshoot is smaller than currently used in published isochrones. We also verify that all current theoretical models for the lower main sequence (with the exception of Baraffe et al. 1998) are too blue for M_V >~ 6 even when the sequences are shifted to match M67 near the M_V of the Sun, probably due to a combination of problems with color-T_eff transformations and realistic surface boundary conditions for models. Finally, we identify a subset of cluster members with unusual photometry (candidate red giant binaries, blue straggler stars, and triple systems) deserving of further study.Comment: 25 pages, 15 figures, accepted for MNRA

The Management of Cyanotic Spells in Children with Oesophageal Atresia

Cyanotic spells, also known as blue spells, dying spells, or apparent life-threatening events, refer to a bluish tone visible in the mucosal membranes and skin caused by an oxygen decrease in the peripheral circulation. Although this decrease may be transient and benign, it may also be indicative of a severe underlying problem that requires immediate intervention. Children with oesophageal atresia (OA) are at risk for a number of coexisting conditions that may trigger cyanotic spells. This current article will focus on the management of cyanotic spells both in children with innominate artery compression and those with tracheomalacia