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Recherche uO, le dépôt numérique de l'Université d'Ottawa, réunit le matériel de recherche et d'enseignement créé par notre communauté universitaire et nos partenaires. Le savoir de l'Université est ainsi disponible à long terme et en accès libre, ce qui lui procure de la visibilité et facilite sa diffusion.

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Geotechnical Response of Cemented Paste Backfill under the Multiphysics Coupled Conditions in Deep Mines
(Université d'Ottawa | University of Ottawa, 2026-07-30) Liu, Hongbin; Fall, Mamadou
Cemented paste backfill (CPB), a mixture of tailings, water, and binder, is widely used in underground mining to stabilize mine openings, improve ore recovery, and enable underground disposal of mine wastes. The geotechnical behaviour of CPB, including strength development, deformation response, stress-strain behavior, and pore water pressure evolution, is critical to the safe and economic design of backfill structures. In deep mines, however, CPB does not cure under conventional stress-free laboratory conditions. Instead, it hardens under coupled thermal-hydraulic-mechanical-chemical (THMC) conditions, including time-dependent vertical self-loading, closure-driven multiaxial confinement, elevated field temperature, drainage or no-drainage boundaries, and possible seepage/infiltration. These coupled processes strongly affect CPB hardening and can fundamentally alter the mechanisms governing its performance. The main objective of this thesis is to investigate the behaviour of CPB under deep-mine-representative curing conditions, with emphasis on the coupled effects of time-dependent multiaxial stress, hydraulic boundary evolution, and elevated field temperature. To achieve this objective, a novel multiaxial compressive stress curing and monitoring apparatus was developed to reproduce closure-related deep-mine curing conditions at laboratory scale. Using this system, a coordinated experimental programme was conducted to examine the effects of multiaxial stress path, horizontal closure magnitude/rate, directional anisotropy, confinement timing, drainage and seepage condition, elevated temperature, and integrated THMC factor combinations on CPB behaviour. The results show that CPB behaviour in deep mines is fundamentally stress-path dependent and multiphysics controlled. Strength development, deformation evolution, positive pore water pressure (PWP), and suction cannot be interpreted from stress magnitude, temperature, or binder content alone. Instead, the response depends on the coupled evolution of multiaxial stress path and stress history, thermal exposure, and hydraulic boundary conditions during curing. Time-dependent multiaxial confinement significantly modifies CPB hardening by promoting stress-assisted densification, changing pore structure evolution, and altering the hydraulic state during curing. The results demonstrate that confinement timing, closure intensity, and directional balance govern whether closure acts as a beneficial densification mechanism or shifts toward damage-dominated behaviour. Moderate and well-balanced confinement can enhance strength, whereas excessive or highly anisotropic closure can reduce densification efficiency, induce cracking, and compromise structural integrity. The hydraulic response of CPB under deep-mine curing is shown to be a critical component of both early-age safety and long-term performance. Closure-driven confinement amplifies and prolongs early-age positive PWP, increasing hydraulic demand on barricades, while controlled drainage reduces the magnitude and duration of this risk. After positive PWP dissipates, suction develops as hydration and/or drainage drive desaturation. Suction evolution is also stress-path dependent: mechanical confinement delays suction onset by maintaining high saturation, while stronger late-age confinement may induce a stress-related resaturation tendency. Elevated temperature accelerates hydration and can intensify both early-age PWP response and later-age suction development through faster water consumption. In contrast, seepage/infiltration acts as a major disturbance by suppressing or collapsing suction and by reducing retained ionic inventory through dilution and solute transport, thereby limiting later-age hydration and strength gain. The thesis further demonstrates that thermal and mechanical effects interact synergistically under deep-mine THMC curing. Elevated temperature strengthens CPB mainly through a hydration-controlled pathway, while multiaxial confinement strengthens CPB mainly through a structure-controlled pathway with stress-assisted hydration. When acting together, these effects reinforce each other, producing the highest strength development under deep-mine-representative conditions. Factor-isolation analysis shows that, within the tested ranges, thermal and mechanical effects are the dominant contributors to strength enhancement, while hydraulic conditions remain essential regulators of safety and performance efficiency. Binder content sets the achievable strength ceiling, but actual strength depends on whether the curing environment allows hydration products to form, remain, and be effectively integrated into a stable load-bearing skeleton. Overall, this thesis establishes that conventional stress-free laboratory curing does not reliably represent CPB behaviour in deep underground mines. It provides experimentally constrained evidence that CPB performance in deep mines is governed by the coupled evolution of multiaxial stress path, hydraulic boundary conditions, and thermal exposure during curing. The findings develop a mechanistic framework for understanding CPB response in closure-dominated deep-mine environments and provide a stronger basis for safer, more realistic, and more cost-effective backfill design.
Learning Management Systems as Contextually Mediated Practice: A Qualitative Case Study of Teachers in Nigerian Private K–12 Schools
(Université d'Ottawa | University of Ottawa, 2026-07-30) Aboaja, Ijeoma Chisolum; Koné, El Hadji Yaya
Learning Management Systems have been widely promoted as a way of using digital innovation to improve teaching and learning. In the Global South, Nigeria provides a context where limited infrastructure, institutional pressures, and unequal digital access often affect how LMS is adopted and make its educational benefits harder to achieve. This qualitative exploratory case studies examines the adoption, mediation, and use of LMS platforms in Nigerian private K–12 schools. It uses Activity Theory and Social Constructivist ideas to explore how LMS platforms are used in complex educational systems. Data were collected through virtual semi-structured interviews with 14 teachers and 1 school leader, as well as by reviewing school websites and taking field notes. Thematic analysis was used to identify which platforms schools use, how they use them, contradictions within the activity systems, and the factors shaping teachers’ instructional methods. The results show that LMS adoption was institutionally driven rather than teacher-initiated, with their use often limited by dynamic features such as disciplinary practices, and infrastructural challenges. Teachers adapted and pragmatically engaged with LMS tools. The study contributes to theory by extending Activity Theory to illustrate how external actors and contextual constraints mediate digital pedagogy in K–12 settings within the Global South. It also challenges the dominant narratives that adopting LMS is always transformational, highlighting the importance of pedagogically driven and context-sensitive implementation strategies. The study concludes with recommendations for policymakers, school leaders, educators, and LMS developers to help make LMS integration more equitable and effective in educational contexts with limited technology.
A Novel High-Throughput Screen Identifies Abemaciclib as a Potent Inducer of Physiologic Hypertrophy and Cardioprotection
(Université d'Ottawa | University of Ottawa, 2026-07-30) Sharma, Anupam; Megeney, Lynn
Physiologic cardiac hypertrophy (PhCH) is an adaptive process associated with endurance exercise training that enhances cardiac function and offers protection against heart failure (HF). However, translating PhCH into effective therapies has been hampered by a limited understanding of the underlying molecular signals. Here, we developed a novel high-throughput screen based on a key morphometric adaptation to PhCH, increased cardiomyocyte length, and then screened small molecule libraries to identify compounds that induced this conditioning event in rodent primary cardiomyocytes. The screen identified the CDK4/CDK6 inhibitor abemaciclib (LY2835219), a clinically prescribed anti-cancer agent, as a potent PhCH remodeling cue in both rodent cardiomyocytes and human iPSC-derived cardiomyocytes. siRNA-targeted inhibition of CDK4 expression phenocopied abemaciclib treatment in cardiomyocytes, confirming the necessity to suppress CDK4 as a general prerequisite for inducing PhCH. In addition, RNA sequencing and phosphoproteomic analysis of cardiomyocytes treated with abemaciclib revealed activation of the protein kinase A (PKA) and AMP-activated protein kinase (AMPK) cascades, consistent with the known metabolic enhancement described in PhCH-induced remodeling. Finally, we noted that in vivo administration of abemaciclib improved cardiac function at baseline and maintained cardiac performance even in the presence of pathologic remodeling signals. These findings identify abemaciclib as a first-in-class therapeutic agent capable of inducing PhCH and suggest suppressing CDK4/6 in general as an unanticipated means to limit pathologic hypertrophy and heart failure.
Le nationalisme corse et la centralisation de la République française, quel type de relation?
(Université d'Ottawa | University of Ottawa, 2026-07-30) Pasetto, Aurelio; Lecours, André
Cette thèse de maîtrise s’intéresse au cas du nationalisme corse au sein d’une France qui présente des caractéristiques de centralisation réduisant les possibilités d’avancées vers l’autonomie politique de l’île. En s’intéressant à la période qui va de la Corse indépendante (1755-1769) à la normalisation nationaliste depuis 2010, cette recherche vise à montrer comment l’identité de la Corse est vécue et utilisée par les nationalistes pour défendre des revendications d’autonomie. La thèse met au point un bilan de l’identité sociale corse en se basant sur un cadre théorique choisi, l’ethnosymbolisme. Le travail souhaite aussi montrer l’importance centrale de la relation entre la France et la Corse pour comprendre le mouvement nationaliste de cette dernière. Une idée de réaction nationaliste est soutenue tout au long du travail. L’écart social et identitaire entre la Corse plus rurale, chrétienne, aux rapports personnels et rapprochés, voire claniques, et la France à la république laïque, universelle et idéelle permet de comprendre les différends qui sont en jeu. Le travail s’intéresse à la relation franco-corse dans la durée pour montrer que l’annexion de 1769, suivie de la républicanisation et du bouleversement des Trente Glorieuses fondent les bases de la réaction nationaliste corse. Il est aussi montré à quel point la langue corse est revendiquée par les nationalistes face à l’imposition du français. La thèse questionne alors la forme de l’État français unitaire en proposant de travailler sur l’étude particulière du cas corse.
Environmental Niche Limits and Climatic Vulnerability in Terrestrial Vertebrates
(Université d'Ottawa / University of Ottawa, 2026-07-29) Nagy-Watson, Matthew James; Kerr, Jeremy T.
À la demande de l'auteur, le résumé a été retiré en raison de la nature confidentielle de la thèse. Il sera ajouté une fois la période d'embargo terminée. At the author’s request, the abstract has been removed due to the confidential nature of the thesis. It will be added once the embargo period has passed.