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Magnetic field configuration associated with solar gamma ray flares in June, 1991

The vector magnetic field configuration of the solar active region AR 6659 that produced very high levels of flare activity in Jun. 1991 is described. The morphology and evolution of the photospheric fields are described for the period 7-10 Jun., and the flares taking place around these dates and their locations relative to the photospheric fields are indicated. By comparing the observed vector field with the potential field calculated from the observed line-of-sight flux, we identify the nonpotential characteristics of the fields along the magnetic neutral lines where the flares were observed. These results are compared with those from the earlier study of gamma-ray flares

Le dispositif de revitalisation du quartier Sainte-Marie à Montréal

Ce mémoire explore les dynamiques propres à la mise en place de politiques de revitalisation dans un quartier urbain montréalais. La revitalisation, accompagnée de nombreux autres « processus » connexes, comme la participation citoyenne et la concertation, participe à une tentative de gouvernement des espaces urbains à travers ce que j’ai appelé ici le dispositif de revitalisation. Le dispositif de revitalisation du quartier Sainte-Marie est le résultat de la mise en place d’une série de pratiques gouvernementales ainsi que de mutations dans la façon de gérer les affaires publiques propres au Québec, et plus particulièrement, à la grande région de Montréal. L’analyse se centre ici sur l’évolution de différentes tendances tant au niveau associatif, communautaire que privé et institutionnel afin de cerner les dynamiques propres au fonctionnement actuel du dispositif dans le quartier de Sainte-Marie, situé dans l’arrondissement Ville-Marie. La formation de ce dispositif est une partie d’un phénomène plus large de transformation des espaces urbains par différentes interventions gouvernementales et privées, à l’ère du néolibéralisme contemporain. Le dispositif est ancré dans tout un florilège d’idées et de pratiques qui doivent être justifiées par le recours à un nouveau vocabulaire et à des concepts qui demeurent volontairement flous et mal définis afin d’en arriver, pour les acteurs concernés, à conserver une liberté d’action nécessaire et d’en restreindre l’accès.This thesis addresses the tensions that arise when urban renewal policies are implemented in a Montreal neighbourhood. Urban renewal, along with other “processes” like public participation and institutional consultation, participates an attempt at governing urban spaces through what is called here an urban renewal apparatus (dispositif). The Sainte-Marie urban renewal apparatus came about through a series of governmental actions as well as transformations in the way public affairs are managed in Quebec, and especially in the greater Montreal region. The analysis is centered here on the evolution of certain tendencies in the community, institutional and private sectors. I aim here to explore the dynamics of the inner workings of the apparatus in the Sainte-Marie neighbourhood. The birth of the apparatus is part of a larger phenomenon of transformation of urban spaces by governmental as well as private initiatives in an era of contemporary neoliberalism. This apparatus is constantly justified and explained through an original set of ideas and actions that are legitimised using a new vocabulary and new concepts that are voluntarily vague and ill-defined as to allow the actors to retain a certain freedom and expertise, and to limit access to its instances

Guide de lutilisation pédagogique des médias sociaux

Titre de l'écran-titre (visionné le 24 jan. 2013)Cette publication est mise à disposition selon les termes de la licence "Créative Commons". Vous êtes libres de l'utiliser, en tout ou en partie en citant l'auteur, vous ne pouvez pas l'utiliser pour un usage commercial et vous n'êtes pas autorisés à la modifier

Early immune pressure initiated by tissue-resident memory T cells sculpts tumor evolution in non-small cell lung cancer

Tissue-resident memory T (TRM) cells provide immune defense against local infection and can inhibit cancer progression. However, it is unclear to what extent chronic inflammation impacts TRM activation and whether TRM cells existing in tissues before tumor onset influence cancer evolution in humans. We performed deep profiling of healthy lungs and lung cancers in never-smokers (NSs) and ever-smokers (ESs), finding evidence of enhanced immunosurveillance by cells with a TRM-like phenotype in ES lungs. In preclinical models, tumor-specific or bystander TRM-like cells present prior to tumor onset boosted immune cell recruitment, causing tumor immune evasion through loss of MHC class I protein expression and resistance to immune checkpoint inhibitors. In humans, only tumors arising in ES patients underwent clonal immune evasion, unrelated to tobacco-associated mutagenic signatures or oncogenic drivers. These data demonstrate that enhanced TRM-like activity prior to tumor development shapes the evolution of tumor immunogenicity and can impact immunotherapy outcomes

Woody lianas increase in dominance and maintain compositional integrity across an Amazonian dam-induced fragmented landscape

Tropical forest fragmentation creates insular biological communities that undergo species loss and changes in community composition over time, due to area- and edge-effects. Woody lianas thrive in degraded and secondary forests, due to their competitive advantage over trees in these habitats. Lianas compete both directly and indirectly with trees, increasing tree mortality and turnover. Despite our growing understanding of liana-tree dynamics, we lack detailed knowledge of the assemblage-level responses of lianas themselves to fragmentation, particularly in evergreen tropical forests. We examine the responses of both sapling and mature liana communities to landscape-scale forest insularization induced by a mega hydroelectric dam in the Brazilian Amazon. Detailed field inventories were conducted on islands created during reservoir filling, and in nearby mainland continuous forest. We assess the relative importance of variables associated with habitat fragmentation such as area, isolation, surrounding forest cover, fire and wind disturbance, on liana community attributes including abundance, basal area, diversity, and composition. We also explore patterns of liana dominance relative to tree saplings and adults ≥10 cm diameter at breast height. We find that 1) liana community composition remains remarkably similar across mainland continuous forest and islands, regardless of extreme area- and edge- effects and the loss of vertebrate dispersers in the latter; and 2) lianas are increasing in dominance relative to trees in the sapling layer in the most degraded islands, with both the amount of forest cover surrounding islands and fire disturbance history predicting liana dominance. Our data suggest that liana communities persist intact in isolated forests, regardless of extreme area- and edge-effects; while in contrast, tree communities simultaneously show evidence of increased turnover and supressed recruitment. These processes may lead to lianas becoming a dominant component of this dam-induced fragmented landscape in the future, due to their competitive advantage over trees in degraded forest habitats. Additional loss of tree biomass and diversity brought about through competition with lianas, and the concurrent loss of carbon storage, should be accounted for in impact assessments of future dam development

Combing Chromosomal DNA Mediated by the SMC Complex: Structure and Mechanisms

Genome maintenance requires various nucleoid‐associated factors in prokaryotes. Among them, the SMC (Structural Maintenance of Chromosomes) protein has been thought to play a static role in the organization and segregation of the chromosome during cell division. However, recent studies have shown that the bacterial SMC is required to align left and right arms of the emerging chromosome and that the protein dynamically travels from origin to Ter region. A rod form of the SMC complex mediates DNA bridging and has been recognized as a machinery responsible for DNA loop extrusion, like eukaryotic condensin or cohesin complexes, which act as chromosome organizers. Attention is now turning to how the prototype of the complex is loaded on the entry site and translocated on chromosomal DNA, explaining its overall conformational changes at atomic levels. Here, we review and highlight recent findings concerning the prokaryotic SMC complex and discuss possible mechanisms from the viewpoint of protein architecture