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Chemo- and Regioselective Demethylation of 2-Bromo-α-resorcylic Acid Derivatives Using Alkylthiolate Salts
Full text linkWe report here the chemo- and regioselective demethylation of 2-bromo-3,5-dimethoxy-α-resorcylic acid esters by a thiolate nucleophilic displacement reaction. Optimized conditions facilitate yields up to 93% for o-bromo-selective demethylation of diverse ester derivatives of dimethoxy 2-bromo-α-resorcylic acid. Our results highlight a new, efficient, and reliable demethylation reagent, as well as a useful steric bias directing strategy
Les facteurs favorables à la rétention en contexte de télétravail dans le secteur des technologies de l'information au Québec
Full text linkRÉSUMÉ : Cette recherche se concentre sur la rétention des employés dans le secteur des technologies de l’information du Québec, spécifiquement dans un cadre de télétravail exclusif. Plus précisément, l’objectif de ce mémoire est d’explorer, d’identifier et de décrire les facteurs de rétention des employés du secteur des technologies de l’information en contexte exclusif de télétravail au Québec. La pandémie de COVID-19, survenue en 2020, a marqué un tournant décisif en instaurant le télétravail exclusif comme norme organisationnelle dans plusieurs milieux. Il s’agit dès lors de s’intéresser à l’influence que cette situation a pu avoir sur la rétention organisationnelle. Le cadre méthodologique adopté pour cette étude est de nature qualitative, orienté vers une approche exploratoire. L’étude repose sur la tenue de groupes de discussion avec des employés œuvrant dans le domaine des technologies de l’information et des communications. Trois groupes de discussion, totalisant un échantillon de 22 personnes, ont été organisés pour identifier les facteurs de rétention dans un cadre de télétravail exclusif. Au cours de ces discussions, les participants ont partagé leurs expériences en matière d’intégration, de collaboration en équipe et de relations avec leurs gestionnaires. Parmi les principaux facteurs de rétention identifiés se trouvent la flexibilité offerte par le télétravail, la conciliation travail-vie personnelle, le soutien entre collègues et une culture d’entraide au sein des équipes. Les défis évoqués incluent le manque de contact humain, les difficultés de communication, ainsi que la nécessité d’améliorer le soutien à l’intégration et à la formation des nouveaux employés. -- Mot(s) clé(s) en français : rétention organisationnelle, télétravail, technologie de l’information et des communications, gestion. --
ABSTRACT :This research focuses on employee retention in the information technology (IT) sector, specifically in the context of exclusive telecommuting in Quebec. More precisely, the aim of this thesis is to explore, identify, and describe the factors influencing employee retention in the IT sector within the context of exclusive telecommuting in Quebec. The COVID-19 pandemic, which occurred in 2020, marked a decisive turning point by establishing exclusive telecommuting as an organizational norm in many workplaces. Therefore, this study seeks to examine the impact that this situation may have had on organizational retention. The methodological framework adopted for this study is qualitative, with an exploratory approach. The study relies on focus groups with employees working in the field of information and communication technologies (ICT). Three focus groups, totaling a sample of 22 people, were organized to identify retention factors in the context of exclusive telecommuting. During these discussions, participants shared their experiences regarding integration, team collaboration, and relationships with their managers. Among the main retention factors identified were the flexibility offered by telecommuting, work-life balance, peer support, and a culture of mutual assistance within teams. The challenges mentioned included the lack of human contact, communication difficulties, and the need to improve support for the integration and training of new employees. -- Mot(s) clé(s) en anglais : organizational retention, telecommuting, information and communication technology, management
Serge Bouchard, une philosophie morale « impréméditée et fortuite » ? écrire la vie, le temps et la nature dans C'était au temps des mammouths laineux, Les yeux tristes de mon camion et L'allume-cigarette de la Chrysler noire
Full text linkRÉSUMÉ : Ce mémoire s’intéresse aux derniers recueils d’essais de Serge Bouchard, C’était au temps des mammouths laineux, Les Yeux tristes de mon camion et L’Allume-cigarette de la Chrysler noire. À cheval entre littérature et philosophie, la question à laquelle ce mémoire répond est de savoir comment s’exprime la philosophie accidentelle de Serge Bouchard dans ses essais tardifs. Cette question se fonde sur une série d’hypothèses démontrées dans le premier chapitre du mémoire, soit que les trois recueils du corpus appartiennent, selon la défi-nition du genre de Jean Marcel, au genre de l’essai, que Serge Bouchard occupe une place particulière au sein de l’essai québécois contemporain, place définie dans un troisième temps comme celle d’un philosophe accidentel. Reprenant les mots de Montaigne qui se considère lui-même comme un philosophe « imprémédité et fortuit », ce mémoire s’inspire des travaux d’Ann Hartle qui dégage quatre caractéristiques de cette philosophie fortuite : une visée non autoritaire, non préméditée et intuitive, une « dialectique circulaire » qui part du commun et du familier pour parvenir à de nouvelles idées, une vision du monde et du savoir radicalement contingente et incarnée qui permet d’atteindre un second sense et donc de porter un regard nouveau sur des réalités connues. Le deuxième chapitre de ce mémoire analyse donc les trois recueils d’essais du corpus à la lumière de cette philosophie accidentelle et des caractéristiques de l’essai tout en examinant trois grands ensembles thématiques : la vie humaine, la vieillesse et la mort, le temps, sa défense de la lenteur ainsi que le rapport éclairé au passé et à la mé-moire (notamment sur le passé colonial nord-américain) et enfin la manière d’envisager l’espace, la nature, le territoire, la faune et la flore. Le but de cette démarche est de dégager les principales idées de l’essayistes sur ces thématiques tout en se penchant sur le style propre à ses essais tardifs pour en délimiter la poétique. En définitive, Serge Bouchard peut être consi-déré comme un philosophe accidentel dont la pensée prend une tournure morale car son œuvre essayistique tardive peut être lue comme de nombreux critiques ont lu l’œuvre de Montaigne : en y dégageant des lignes directrices sur la vie humaine et en offrant une lecture morale de son œuvre. -- Mot(s) clé(s) en français : essai, Montaigne, littérature québécoise contemporaine, littérature et savoirs, littérature et philosophie, style. --
ABSTRACT : This thesis explores Serge Bouchard's latest collections of essays, C'était au temps des mammouths laineux, Les Yeux tristes de mon camion and L'Allume-cigarette de la Chrysler noire. Straddling literature and philosophy, the question this thesis addresses is how Serge Bouchard's accidental philosophy is expressed in his late essays. This question is based on a series of hypotheses demonstrated in the first chapter of the thesis, namely that the three col-lections in the corpus belong, using Jean Marcel's definition of the genre, to the genre of the essay, that Serge Bouchard occupies a particular place within the contemporary Quebec es-say, a place defined in a third stage as that of an accidental philosopher. In the words of Mon-taigne, who considered himself an “unpremeditated and accidental” philosopher, this thesis draws on the work of Ann Hartle, who identifies four characteristics of this accidental phi-losophy: a non-authoritarian, unpremeditated and intuitive aim; a “circular dialectic” that starts from the common and the familiar to arrive at new ideas; and a radically contingent and em-bodied vision of the world and of knowledge, which enables us to reach a second sense and thus take a fresh look at known realities. The second chapter of this thesis therefore analyzes the three collections of essays in the corpus in the light of this accidental philosophy and the characteristics of the essay, while examining three major thematic clusters: human life, old age and death; time, Bouchard’s defense of slowness and enlightened relationship with the past and memory (notably on North America's colonial past); and finally, his way of looking at space, nature, territory, fauna and flora. The aim of this approach is to identify the essayist's main ideas on these themes, while examining the style of his late essays to delineate their po-etics. Ultimately, Serge Bouchard can be considered an accidental philosopher whose thought takes on a moral twist, for his late essayistic work can be read as many critics have read Mon-taigne's: by drawing out guidelines for human life and offering a moral reading of his work. -- Mot(s) clé(s) en anglais : essay, Montaigne, contemporary Quebec literature, literature and knowledge, literature and philosophy, style
Incidence de la gestion durable des projets de construction sur la réduction de l'empreinte carbone
Full text linkRÉSUMÉ : L'industrie de la construction joue un rôle essentiel dans le développement économique mondial, mais elle est aussi l'une des principales sources d'émissions de gaz à effet de serre. Face aux enjeux environnementaux croissants, il devient impératif d'adopter des pratiques de gestion durable de projets pour réduire l'empreinte carbone des projets de construction. Ce mémoire examine les approches novatrices visant à concilier développement économique et préservation de l'environnement. Cette recherche est divisée en plusieurs chapitres qui examinent l'incidence de la gestion durable des projets de construction sur la réduction de l'empreinte carbone. La première partie présente une revue de la littérature sur les concepts clés du sujet. L'analyse bibliométrique, basée sur les outils VOSviewer et SciMAT, met en lumière les principales tendances et évolutions dans ce domaine. Enfin, une analyse de contenu approfondie des articles sélectionnés identifie les pratiques les plus efficaces et les obstacles à leur adoption. -- Mot(s) clé(s) en français : Gestion durable de projets, industrie de construction, empreinte carbone. --
ABSTRACT : The construction industry plays a vital role in global economic development, but it is also one of the main sources of greenhouse gas emissions. In the face of growing environmental challenges, it is becoming imperative to adopt sustainable management practices to reduce the carbon footprint of construction projects. This thesis examines innovative approaches to reconcile economic development and environmental preservation. This research is divided into several chapters, each analyzing the impact of sustainable management of construction projects on reducing the carbon footprint. The first part presents a literature review on the key concepts of the subject. A bibliometric analysis, using VOSviewer and SciMAT tools, highlights the main trends and developments in this field. Finally, an in-depth content analysis of the selected articles identifies the most effective practices and the barriers to their adoption. -- Mot(s) clé(s) en anglais : Sustainable project management, construction industry, carbon footprint
Cumulative effects of mutation accumulation on mitochondrial function and fitness
Full text linkThe impact of mutations on the mitochondria deserves specific interest due to the crucial role played by these organelles on numerous cellular functions. This study examines the effects of repeated bottlenecks on mitochondrial function and fitness. Daphnia pulex mutation accumulation lines (MA) lines were maintained for over 120 generations under copper and no copper conditions. Following the MA propagation, Daphnia from MA lines were raised under optimal and high temperatures for two generations before assessing mitochondrial and phenotypic traits. Spontaneous mutation accumulation under copper led to a later age at maturity and lowered fecundity in the MA lines. Mitochondrial respiration was found to be 10% lower in all mutation accumulation (MA) lines as compared to the non-MA control. MtDNA copy number was elevated in MA lines compared to the control under optimal temperature suggesting a compensatory mechanism. Three MA lines propagated under low copper had very low mtDNA copy number and fitness, suggesting mutations might have affected genes involved in mtDNA replication or mitochondrial biogenesis. Overall, our study suggests that mutation accumulation had an impact on life history traits, mtDNA copy number, and mitochondrial respiration. Some phenotypic effects were magnified under high temperatures. MtDNA copy number appears to be an important mitigation factor to allow mitochondria to cope with mutation accumulation up to a certain level beyond which it can no longer compensate
Comparative analysis of the high-temperature tensile properties of laser-welded AA5052 and AA6061 for automotive applications
Full text linkThis study investigates the high-temperature tensile properties of laser-welded AA5052-H36 and AA6061-T6 aluminum alloys, utilizing experimental and statistical analysis. Tensile tests were conducted at temperatures ranging from 25°C to 300°C at corresponding strain rates of 0.01 and 0.1 s−1. The results indicate that AA5052-H36 exhibits superior mechanical strength compared to AA6061-T6, with a near-linear decrease in ultimate tensile strength, showing a reduction of approximately 60% from 273 MPa at 100°C to 108 MPa at 300°C. AA5052-H36 also shows consistent increases in fracture strain across the tested conditions, with fracture strain rising from 0.14 at 100°C to 0.37 at 300°C. In contrast, AA6061-T6 displays a non-linear decline in UTS, dropping by 51%, from 220 MPa at 100°C to 110 MPa at 300°C, and an increase in fracture strain from 0.05 at 100°C to 0.07 at 300°C. This non-linear behavior is linked to the dissolution of β″ phases and the subsequent precipitation of β′ phases, as revealed by the differential scanning calorimetry curve. Statistical analysis confirms that temperature is the dominant factor influencing tensile performance, with notable contributions from phase transformations observed in the DSC curve. Energy absorption analysis highlights the advantages of AA5052-H36, which absorbs considerably more energy before failure compared to AA6061-T6, due to its greater plastic deformation capacity. AA5052-H36 absorbs up to 13.3 J at 250°C, while AA6061-T6 absorbs a maximum of 3.3 J at the same temperature. Both alloys show maximum energy absorption at 250°C, with increasing temperature leading to a rise in absorbed energy up to 13.3 J. However, beyond 250°C, the energy absorption decreases substantially. In conclusion, while AA5052-H36 may offer superior performance in high-temperature tensile loading compared to AA6061-T6, the choice of alloy for applications above 250°C should be made with careful consideration of the trade-offs, including strength, corrosion resistance, and manufacturability, to prevent possible creep-related failures
Societal drivers for the integration of hydrogeomorphology and human benefits in river restoration projects
Full text linkIntegrating hydrogeomorphological (HGM) principles into the restoration of degraded rivers can achieve sustainable results and provide various human benefits. HGM principles mainly involve understanding the context and processes that shape a fluvial system before any intervention, in order to support its dynamism and to align with its potential functioning and uses. Despite recent management approaches inspired by HGM principles, most restoration projects carried out in Quebec (Canada) are not process-based and target specific one-dimensional objectives. Although there is an overall lack of post-project monitoring, several projects appear to have failed or had mixed success. This research aims to shed light on the diversity of societal drivers behind river restoration projects and to examine how they influence the integration of HGM principles and human benefits. Four restoration projects were characterized through participant observation and interviews with the organizations running them. Representatives of two ministries involved in river restoration and management were also interviewed. The results show that projects were mainly shaped by public acceptance disregarding HGM principles, which can lead to poorly-informed action. Project funding and stakeholders' expertise have also challenged project implementation and played a key role in defining their objectives. The addition of these components improve the current analytical frameworks for identifying river restoration objectives. Depending on specific sociocultural, political and legislative contexts, funding programs and stakeholders' expertise may either facilitate or restrict the integration of HGM principles and human benefits in the projects. Recognizing these key drivers reframes river restoration as a fundamentally social activity and enlightens how they could impel innovative approaches towards more sustainable results
Polyploidy confers better cold tolerance in Daphnia
Full text linkDespite decades of studies on the differential distribution of polyploid organisms, the causes of this pattern have yet to be elucidated. This study aimed to explore some of the possible physiological mechanisms explaining the differential northern distribution of polyploid clones of Daphnia pulex compared to the one of the diploid parental species. The critical thermal minimum (CTmin) was measured in 17 D. pulex clones of contrasted ploidy (diploid and triploid) and geographic origins (temperate and subarctic climates) reared under low and high temperatures (16 and 24°C). Triploid clones had better cold tolerance (lower CTmin) than both sympatric and temperate diploid clones. No significant association was found between CTmin and body size nor with cell size. We suggest that triploids might express a cold shock resistant phenotype related to higher gene expression and/or fatty acid profiles. Cold tolerance can be viewed as one of the possible reasons for polyploid preponderance in subarctic climates
Utilisation de la chimie des otolithes pour caractériser le régime alimentaire du sébaste (Sebastes sp.)
Full text linkRÉSUMÉ : Le sébaste (Sebastes sp.) est une espèce clé du golfe du Saint-Laurent, dont la biomasse a considérablement augmenté depuis 2014. Cette croissance rapide pourrait impacter des espèces commerciales telles que la crevette nordique (Pandalus borealis), qui constitue une proie importante pour le sébaste. Pour mieux comprendre les interactions écologiques du sébaste, il est nécessaire d'analyser son régime alimentaire et ses effets sur son environnement. L'objectif de cette étude est d'évaluer l'influence de différents régimes alimentaires sur la chimie des otolithes du sébaste, en particulier l'incorporation d'éléments traces comme le baryum (Ba) et le strontium (Sr). Ces éléments peuvent fournir des informations cruciales sur les habitudes alimentaires des poissons. Afin de tester cette hypothèse, une expérience en laboratoire a été menée sur des sébastes soumis à cinq régimes alimentaires différents, qui incluaient des proies telles que la crevette nordique et le capelan (Mallotus villosus). Pendant six mois, les poissons ont été nourris dans des conditions contrôlées, puis leurs otolithes ont été analysés à l'aide de la spectrométrie de masse à ablation laser. Les résultats ont montré que la consommation de crevettes entraînait une augmentation significative des concentrations de Ba et Sr dans les otolithes, tandis que les poissons nourris uniquement au capelan présentaient des concentrations plus faibles. En outre, les poissons ayant changé de régime alimentaire au cours de l'expérience ont affiché des variations dans les concentrations d'éléments traces, suggérant que ces changements peuvent être détectés par l'analyse des otolithes. En conclusion, cette étude démontre que la chimie des otolithes est un outil prometteur pour caractériser le régime alimentaire du sébaste et suivre les variations de son comportement alimentaire dans le golfe du Saint-Laurent. Ces résultats contribuent à une meilleure compréhension de l'écologie alimentaire du sébaste et peuvent aider à la gestion durable des populations de cette espèce. -- Mot(s) clé(s) en français : sébaste, physiologie, otolithes, régime alimentaire, éléments traces. --
ABSTRACT : Redfish (Sebastes sp.) is a key species in the Gulf of St. Lawrence, whose biomass has significantly increased since 2014. This rapid growth may affect other commercially important species such as northern shrimp (Pandalus borealis), a major prey for redfish. To better understand redfish’s ecological interactions, it is crucial to analyze its diet and its environmental impact. The objective of this study is to assess the influence of different diets on the otolith chemistry of redfish, particularly the incorporation of trace elements such as barium (Ba) and strontium (Sr), which can provide essential insights into fish feeding habits. To test this hypothesis, a laboratory experiment was conducted where redfish were subjected to five different diets, mixing two redfish preferential prey: northern shrimp and capelin (Mallotus villosus). Over six months, the fish were fed under controlled conditions, then their otoliths were analyzed using laser ablation mass spectrometry. The results showed that shrimp consumption significantly increased Ba and Sr concentrations in otoliths, while fish fed exclusively on capelin exhibited lower concentrations. Additionally, fish that underwent dietary changes during the experiment showed variations in trace element concentrations, suggesting that such changes can be detected through otolith analysis. In conclusion, this study demonstrates that otolith chemistry is a promising tool for characterizing redfish diets and tracking variations in their feeding behaviour in the Gulf of St. Lawrence. These findings contribute to a better understanding of redfish feeding ecology and can support the sustainable management of this species. -- Mot(s) clé(s) en anglais : redfish, physiology, otoliths, diet, trace éléments
New Deoxygenation Threshold for N₂ and N₂O Production in Coastal Waters and Sediments
Full text linkBioavailable nitrogen governs ocean productivity and carbon fixation by regulating phytoplankton growth and community composition. Nitrogen input primarily results from N₂ fixation, while denitrification and anammox remove bioavailable nitrogen in oxygen-depleted conditions. Traditionally considered limited to highly suboxic (i.e., <5 μM) waters, recent studies suggest that fixed-nitrogen removal processes may extend beyond, elevating global nitrogen loss estimates. This study directly quantifies fixed-nitrogen loss across oxygen gradients (from 140 to 32 μM) along the Estuary and Gulf of St. Lawrence using N cycle tracers (N₂, Ar, N* and N₂O). Notably, we observe significant N₂ production when ambient O₂ concentrations fall below a threshold value of 58.9 ± 1.1 μM, including potential water column fixed-nitrogen removal processes above suboxia. We hypothesis that ambient deoxygenation eases the formation of suboxic microareas in suspended organic matter. Benthic N₂ production remains unaffected under intensifying water column deoxygenation from 50 down to 32 μM, but the contribution of NO₃- produced through nitrification in the sediment to denitrification diminishes as deoxygenation intensifies. Combined, water column and benthic fixed-nitrogen removal processes drive N* anomalies and strong NO₃- deficiency in bottom waters. Additionally, the observed O₂ threshold also triggers N₂O production. Overall, our study highlights the profound impact of coastal ocean deoxygenation on nitrogen cycling, suggesting unexpected shifts even at ambient oxygen concentrations traditionally considered well above suboxic conditions