TECTONIC EVOLUTION OF THE BAIE VERTE MARGIN, NEWFOUNDLAND

Located along the Early Paleozoic Laurentian continental margin in Newfoundland, the Baie Verte Margin tectonistratigraphy and tectono-metamorphic evolution have been controversial for decades. Here, the results of a detailed field, petrological and geochronological study are presented, where Baie Verte Margin is subdivided into three tectono-metamorphic units separated by tectonic contacts: the East Pond Metamorphic Suite (EPMS) basement, EPMS cover, and the Fleur de Lys Supergroup (FdLS). Each unit exhibits a distinct metamorphic and structural evolution recorded during the subduction, exhumation, and post-collisional history of this ancient margin. The combination of thermodynamic modelling, petrochronology, and structural analysis provided insights into the P-T-t-d paths of the studied units, allowing a better understanding of their role during the evolution of the Taconic subduction system. High-pressure (HP) to ultra-high-pressure (UHP) conditions were reached between 483 and 475 Ma during the D1 phase, with the EPMS cover recording eclogite-facies metamorphism at ~2.8 GPa and 620°C. Subsequent decompression resulted in a β-shaped pressure-temperature-time (P-T-t) path, with near-isothermal decompression to ~2 GPa and heating to 860°C during exhumation. A multi-stage exhumation model is proposed for the EPMS eclogites: 1) buoyant rise through a low-density mantle wedge and 2) subsequent ascent at shallower crustal levels, facilitated by external tectonic forces and slab break-off, as evidenced by Late Taconic magmatism. While the EPMS cover re-equilibrated at UHP conditions, the EPMS basement and FdLS experienced decompression and Barrovian metamorphism during late-D1, indicating decoupling of the units during this stage. Coupling between the units occurred along a D2 shear zone during retrograde metamorphism, spanning 475–452 Ma. Two exhumation scenarios are proposed to explain the tectonic evolution of the margin: (i) Following late D1 detachment, the EPMS basement and FdLS were exhumed to crustal levels while the EPMS cover was subducted deeper into the mantle. Tectonic extrusion along D2 shear zones, potentially aided by melt weakening, then emplaced the EPMS cover between the two units. (ii) Alternatively, sequential detachment occurred from the top to the bottom of the slab, resulting in deeper subduction of lower units, followed by their exhumation through back-folding and crustal wedge thrusting. The Silurian F3 folding deforms both D1-2 structures in each unit and the D2 shear zones that bound them, suggesting that the continental wedges, which recorded different tectono-metamorphic paths after early D1, were juxtaposed before the onset of deformation associated with the Salinic Orogeny. Later deformation phases, D4 and D5, are probably related to tectono-metamorphic activity related to the Acadian and Neo-Acadian orogenies. This research improves our understanding of the dynamic tectono-metamorphic evolution of the Baie Verte Margin, emphasizing the role of fluids, thermal perturbations, and deformation in driving metamorphic reactions, and exhumation. The findings contribute to understanding the mechanisms controlling HP-UHP terrain evolution in subduction zones and highlight the complex interactions between subduction, exhumation, collision, and magmatism throughout the Taconic orogeny

Between the Covers and Beyond the Page: Gauging Climate Fiction's Impact through Ecocriticism and Virtual Book Club Observations

Despite increasing global concern about climate change, a gap persists between climate worry and action. Researchers across various disciplines and popular media suggest that narratives can motivate pro-environmental behaviour. Cli-fi novels, in particular, are believed to influence readers’ behaviours and perceptions of climate change. However, most evidence supporting these claims comes from classroom observations and traditional humanistic inquiry. In 2018, a new research methodology emerged, empirical ecocriticism, which set out to determine how general readers engage with these novels. This dissertation follows the principles of this method, namely, the combination of ecocritical analyses with empirical methods. To that end, the first part of this dissertation (Chapters 2 and 3) is an ecocritical examination of four diverse cli-fi novels published in the last decade to determine how they conveyed climate change information to their readers and how this portrayal may affect readers’ understanding of this issue. The second part of this dissertation (Chapter 4) is a report on empirical findings from a book club observation study of readers reading these same cli-fi novels. The two interdisciplinary objectives of this dissertation were to firstly examine how cli-fi novels relate information about climate change and what aspects of climate change are emphasized to readers in these novels, and secondly to contribute to the emerging field of empirical ecocriticism by reporting on how groups of readers discussed cli-fi novels and the climate change information therein. To achieve these objectives, I: (1) interpreted of four diverse cli-fi novels using ecocritical methods and (2) designed and implemented a book club observation study of general readers reading these same novels. Drawing on ecocriticism, climate change communication, and social sciences research, Chapter 2 introduces a new subcategory of cli-fi – ambivalent cli-fi. This subcategory is defined through an analysis of two realistic cli-fi novels Weather by Jenny Offill and Blaze Island by Catherine Bush to determine how climate change is portrayed in these novels and how their narratives might help readers explore their emotional responses to climate change. The novels were chosen due to their connections to the 2020s and the ecocritical analysis of these novels demonstrates that they can help readers sit in the uncomfortable space where the world is not yet irreversibly ruing, yet there is also no easy solution. Chapter 3 examines Blackfish City by Sam J. Miller and The Marrow Thieves by Cherie Dimaline, two speculative cli-fi novels, whose authors claimed they wanted their readers to feel hope despite narratives that portray radically altered environments and nightmarish societies. This chapter reviews climate change communication research that points towards more inclusive messaging favouring neither hope nor despair. The ecocritical analysis of the two novels utilizes Albert Camus’ notion of the absurd to address the feelings of existential crisis evoked by the novels’ depictions of climate change. It concludes by advocating for the creation of narratives that help audiences find ways to embrace futures that are neither apocalyptic nor utopic. Chapter 4 reports on virtual cli-fi book club sessions conducted from January to June 2022, involving 40 participants from across Canada. Participants read the same cli-fi novels discussed above in order to ascertain how ecocritical readings of these novels might differ from general readers’ interpretations. Pre- and post-survey data indicated that participants were younger than the average Canadian population (65% less than 44 years old compared to 42%), liberal, and concerned about climate change. The study identified three main themes from participant discussions: (1) the relatability of the cli-fi novels enhanced the believability of the story and climate change; (2) the presence or absence of hope was linked to whether novels included individual actions to mitigate climate change; and (3) participants experienced anxiety when they empathized with characters and scenarios. These findings suggest that readers use cli-fi novels to understand current climate issues. Results from the book club observation study also suggested that general readers in groups find solace and reach new conclusions through discussion. This discovery underscores the importance of considering reading as both an individual and social practice for empirical ecocriticism. The conclusions drawn from the ecocritical chapters highlight how cli-fi narratives have the potential to influence reader emotions. The arguments in Chapters 2 and 3 demonstrate that the negative emotions present in each cli-fi novel are necessary for readers to engage with and learn from. Chapter 5 concludes with a comparison of these arguments with the results from the book club study (Chapter 4). This discussion reinforces research from climate change communication and the social sciences that argues audiences (and readers) do not need to be frightened with catastrophic images of climate change dystopias. Instead, what readers (and non-scholarly audiences) might need now are stories that help them learn how to live-with climate uncertainty, and spaces to do this together

Multi-scale Modelling of Neurosteroid-mediated Seizure Trajectories in Childhood Absence Epilepsy

Childhood absence epilepsy (CAE) is a pediatric generalized epilepsy disorder characterized by brief episodes of impaired consciousness and distinctive 2.5--5 Hz spike-wave discharges (SWDs) on electroencephalography. With a well-established genetic aetiology, this condition tends to resolve spontaneously during adolescence in most cases. While several mechanisms have been proposed for remission, understanding remains insufficient to guide early intervention practices. In this thesis, we first utilize a conductance-based thalamocortical network model that exhibits characteristic SWDs, to demonstrate that allopregnanolone---a progesterone metabolite known to enhance GABAa receptor-mediated inhibition---has an ameliorating effect on SWDs. To investigate the divergence between this finding and clinical observations, we developed an enhanced thalamocortical model that incorporates a layered cortical structure to explore regional cortical heterogeneity and frontocortical connectivity as potential resistance factors to ALLO-mediated recovery. Our results suggest that non-resolving CAE may be due not only to increased frontocortical connectivity but also to the composition of cell types within the network. Specifically, a higher proportion of bursting-type cells may prevent the therapeutic effects of allopregnanolone. We extended our investigation to examine whether these findings apply to CAE caused by different genetic mechanisms, particularly mutations in sodium channel genes by modelling their effects at the individual neuron level. Furthermore, we examined the degree to which these alterations lead to network-level pathological activity, as well as the influence of ALLO on these genetically distinct networks. Our results demonstrate that ALLO facilitates recovery from SWDs regardless of the underlying mutation type. However, enhanced frontocortical connectivity prevents recovery in some mutation types, particularly when mutation effects are severe. Altogether, the multi-scale computational framework developed in this thesis demonstrates that CAE remission is determined by complex interactions between hormonal influences, genetic factors, and network connectivity patterns. The results suggest that certain genetic mutations may predispose individuals toward either remission or non-remission, which can be further modulated by connectivity profiles. In particular, enhanced frontocortical connectivity appears to be a significant factor in resistance to hormone-mediated remission. Additionally, this thesis develops techniques for analyzing transitions between distinct dynamical states in neural systems, incorporates genetic and hormonal factors into conductance-based models, and provides a computational framework to identify key parameters governing epileptic activity. These approaches not only advance our understanding of CAE specifically, but offer generalizable insights into the mathematical modelling of neurological conditions characterized by spontaneous shifts in brain dynamics

Model Predictive Control for Systems with Partially Unknown Dynamics Under Signal Temporal Logic Specifications

Autonomous systems are seeing increased deployment in real-world applications such as self-driving vehicles, package delivery drones, and warehouse robots. In these applications, such systems are often required to perform complex tasks that involve multiple, possibly inter-dependent steps that must be completed in a specific order or at specific times. One way of mathematically representing such tasks is using temporal logics. Specifically, Signal Temporal Logic (STL), which evaluates real-valued, continuous-time signals, has been used to formally specify behavioral requirements for autonomous systems. This thesis proposes a design for a Model Predictive Controller (MPC) for systems to satisfy STL specifications when the system dynamics are partially unknown, and only a nominal model and past runtime data are available. The proposed approach uses Gaussian Process (GP) regression to learn a stochastic, data-driven model of the unknown dynamics, and manages uncertainty in the STL specification resulting from the stochastic model using Probabilistic Signal Temporal Logic (PrSTL). The learned model and PrSTL specification are then used to formulate a chance-constrained MPC. For systems with high control rates, a modification is discussed for improving the solution speed of the control optimization. In simulation case studies, the proposed controller increases the frequency of satisfying the STL specification compared to controllers that use only the nominal dynamics model. An initial design is also proposed that extends the controller to distributed multi-agent systems, which must make individual decisions to complete a cooperative task

Pre-treatment direct costs for people with tuberculosis during the COVID-19 pandemic in different healthcare settings in Bandung, Indonesia

© 2025 Lestari et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.The tuberculosis (TB) program was massively disrupted due to the COVID-19 pandemic, which may have impacted on an increase in costs for people with TB (PWTB) and their households. We aimed to quantify the pre-treatment out-of-pocket costs and the factors associated with these costs from patients' perspective during the COVID-19 pandemic in Bandung, Indonesia. Adults with pulmonary TB were interviewed using a structured questionnaire for this cross-sectional study recruiting from 7 hospitals, 59 private practitioners, and 10 community health centers (CHCs) between July 2021 to February 2022. Costs in rupiah were converted into US dollars and presented as a median and interquartile range (IQR). Factors associated with costs were identified using quantile regression. A total of 252 participants were recruited. The median total pre-treatment cost was $35.45 (IQR 17.69-67.62). The highest median cost was experienced by participants from private hospitals ($54.51, IQR 29.48-98.47). The rapid antigen and PCR for SARS-CoV-2 emerged as additional medical costs among 26% of participants recruited in private hospitals. Visiting >-6 providers before diagnosis ($38.40 versus$26.20, p < 0.001), presenting first at a private hospital ($50.68, p< 0.05) and private practitioners ($34.97, p < 0.05), and being diagnosed in the private health sector ($39.98 versus$20.30, p < 0.05) were significantly associated with higher pre-treatment costs. PWTB experienced substantial out-of-pocket costs in the process of diagnosis during the COVID-19 pandemic despite free TB diagnosis and treatment. Early detection and identification play an important role in reducing pre-diagnostic TB costs.Bill & Melinda Gates Foundation, INV-022420

Reweighted Eigenvalues: A New Approach to Spectral Theory beyond Undirected Graphs

We develop a concept called reweighted eigenvalues, to extend spectral graph theory beyond undirected graphs. Our main motivation is to derive Cheeger inequalities and spectral rounding algorithms for a general class of graph expansion problems, including vertex expansion and edge conductance in directed graphs and hypergraphs. The goal is to have a unified approach to achieve the best known results in all these settings. The first main result is an optimal Cheeger inequality for undirected vertex expansion. Our result connects (i) reweighted eigenvalues, (ii) vertex expansion, and (iii) fastest mixing time [BDX04] of graphs, similar to the way the classical theory connects (i) Laplacian eigenvalues, (ii) edge conductance, and (iii) mixing time of graphs. We also obtain close analogues of several interesting generalizations of Cheeger’s inequality [Tre09, LOT12, LRTV12, KLLOT13] using higher reweighted eigenvalues, many of which were previously unknown. The second main result is Cheeger inequalities for directed graphs. The idea of Eulerian reweighting is used to effectively reduce these directed expansion problems to the basic setting of edge conductance in undirected graphs. Our result connects (i) Eulerian reweighted eigenvalues, (ii) directed vertex expansion, and (iii) fastest mixing time of directed graphs. This provides the first combinatorial characterization of fastest mixing time of general (non-reversible) Markov chains. Another application is to use Eulerian reweighted eigenvalues to certify that a directed graph is an expander graph. Several additional results are developed to support this theory. One class of results is to show that adding $\ell_2^2$ triangle inequalities [ARV09] to reweighted eigenvalues provides simpler semidefinite programming relaxations, that achieve or improve upon the previous best approximations for a general class of expansion problems. These include edge expansion and vertex expansion in directed graphs and hypergraphs, as well as multi-way variations of some undirected expansion problems. Another class of results is to prove upper bounds on reweighted eigenvalues for special classes of graphs, including planar, bounded genus, and minor free graphs. These provide the best known spectral partitioning algorithm for finding balanced separators, improving upon previous algorithms and analyses [ST96, BLR10, KLPT11] using ordinary Laplacian eigenvalues

Delay Averse Crew Pairing Optimization

Airline operations involve many complex and interdependent decisions. These include flight scheduling, fleet assignment, maintenance routing, and crew scheduling. Crew scheduling is particularly important, as crew costs are the second-largest expense in airline operations. In practice, delays are common and can cause major disruptions to crew schedules. Most crew pairing models are deterministic and aim to minimize planned costs. However, they often ignore operational uncertainties, such as delays. As a result, they may perform poorly in real operations. This is critical because crew payments are based on actual flight times. This thesis addresses the delay averse crew pairing problem. We propose an optimization model with a delay cost component to create more reliable pairings. The model is based on a duty network structure, and utilizes the pay-and-credit scheme to account for crew payments. We solve the model using Lagrangian relaxation and perform extensive testing on real data. We compare the delay averse model to the nominal case and conduct sensitivity analysis to demonstrate how changes in cost parameters and delay levels affect the solutions. Finally, we evaluate the solutions using simulation based on historical flight delay data. The results show that the delay averse model creates more reliable pairings. These pairings are better at absorbing delays and reducing total propagated delays

Assessment of the Proposed Policies for a Carbon Capture and Storage Regulatory Framework in Ontario

Since 2022, Ontario has been investigating the possibility of developing a Carbon Capture and Storage (CCS) framework as they aim to reduce carbon emissions and align with the federal government’s goals of net-zero emissions by 2050. This CCS regulatory framework should focus on hard-to-abate sectors where alternative renewable energy technologies are in their early stages, or they are difficult to be transitioned. However, within the research field of CCS in Ontario from a policy perspective, there are minimal journal articles and grey-literature documents that discuss this topic. Therefore, the purpose of this thesis is to understand and analyze Ontario’s proposal of their regulatory framework for CCS and to give recommendations to the CCS framework by comparing it against the information gathered from other jurisdictions (Alberta, Saskatchewan, the United States, Europe and Australia). Key research questions are 1. How can the knowledge gained from other regions regarding CCS help Ontario's hard-to-abate sectors to understand approvals, licensing, and liability? 2. What are some other necessary policies that Ontario would need to expand upon and potentially adopt from various jurisdictions? And 3. How did companies and governments in other jurisdictions communicate to the public about the need for this technology? The thesis first developed a literature review to compare and contrast policies from other jurisdictions by researching and synthesizing various peer-reviewed journal articles and grey literature. Then, a semi-structured interview was needed to explore any unique perspectives from interviewees with expertise in CCS, and also to understand whether the results aligned with the information from the literature review. Following the interviews, the analysis of the results were accomplished by using ‘codes’ and ‘themes’, which allows for a simplified understanding of which information is unique. As a result, there were unique findings from the interviews such as ensuring proper industries are utilizing CCS, explaining the purpose of CCS, ensuring that the regulatory framework for CCS is properly developed, and the potential for CCS to utilize a carbon market through an Emissions Trading System (ETS). In November 2024, Ontario introduced Bill 228, which contains an Act called the Geologic Carbon Storage Act, 2024. This Act contains the key core components of the regulatory framework, such as ownership, liabilities, and approvals and assessments. As a result, a description and analysis of this Act was undertaken to understand how it compares against my research findings. In conclusion, to answer the first research question, the findings resulted in requiring Ontario to vest in the pore space, implement a unitization statue, implement a transfer of liabilities once certain pre-conditions are met and a post-stewardship fund to cover liability costs. As for the second research question, the other necessary policies include expanding upon environmental assessments methods, using a systems analysis approach to understand the outcomes of developing CCS, incorporating CCS into carbon pricing schemes, and Ontario’s plans on how they should utilize their CCS. The findings for the final research question recommend that the Ontario government and companies recognize the social demographic backgrounds of Ontario; ensure that Ontario is integrating and engaging with communities closely; explaining the downsides of not developing a CCS project; and respecting a community’s decision if they do not wish to engage with the project. Bill 228 is consistent with these findings, namely the inclusion of a liability transfer; a stewardship fund to cover the liabilities for the Crown; unitization of pore spaces; risk management; monitoring, measurement and verification (MMV); emergency response; and various approvals and assessments. However, the ownership of pore spaces deviates from these findings, as Ontario vests pore ownership to the surface owners but still allows the Crown to vest in the pore space when required

Learning the Quantum, Scrambling the Universe

This thesis explores how quantum information behaves in extreme physical settings, from black hole interiors to noisy quantum devices. First, we derive a thermodynamic relation linking gravitational shockwaves to microscopic deformations of the black hole horizon, illuminating the connection between quantum chaos and horizon area deformation. Next, we explore the black hole information problem through the lens of holography, demonstrating how scrambling and recoverability emerge from gravitational backreaction in shockwave geometries. Finally, we shift to quantum technologies, introducing noise-strength-adapted (NSA) quantum error-correcting codes discovered via hybrid machine learning. These non-stabilizer codes outperform conventional designs under amplitude damping and generalize to larger systems. Together, these works reveal how quantum information unifies seemingly disparate domains, offering both conceptual insights into spacetime and practical tools for building resilient quantum systems

Health Care Costs Associated with Minor Ailments and Cost Minimization Analysis of Pharmacists Prescribing for Minor Ailments in Ontario, Canada

Background: Pharmacists in Ontario, Canada are now able to prescribe for certain minor ailments. Minor ailments are defined as health conditions that can be managed with minimal treatment and/or self-care strategies. Economic evaluations with costs and burden associated with minor ailment conditions using Ontario health administrative data are needed to accurately evaluate the economic impact of the pharmacist prescribing for minor ailment (PPMA) program. Objectives: The objectives of this research thesis are to: 1) assess the baseline characteristics, mean health care costs, and predictors of health care costs of minor ailment cases using a retrospective analysis of Ontario health administrative data for patients presenting with minor ailment conditions and 2) perform a cost-minimization analysis to determine the economic impact of a remunerated program for PPMA compared with usual care. Methodology: First, using Ontario health administrative data from ICES, baseline characteristics, mean health care costs, and predictors of health care costs were determined for patients diagnosed with the 16 studied minor ailments. Second, a decision-analytic model was implemented to perform the cost-minimization analysis for the minor ailments. Two prescribing strategies were considered in this analysis: PPMA and usual care. In the PPMA strategy, patients have the option of either seeking care from a community pharmacist or a physician. In the usual care model, all patients seek care from physicians. Probabilities and costs used in the model were derived from mostly Ontario health administrative data, literature, or expert opinion when there was insufficient literature. This analysis used a public payer perspective and outcomes were expressed in costs in 2019 Canadian dollars. Results: Analysis of Ontario health administrative data from ICES identified that the minor ailments with the highest number of unique patients billed were musculoskeletal sprains and strains (8,099,393; 24%), gastroesophageal reflux disease (5,822,495; 17%), dermatitis (5,649,829; 17%), urinary tract infection (3,356,887; 10%), and insect bites and urticaria (2,699,684; 8%). Health care costs varied by minor ailment and cost category, with older age, lower income quintiles, urban residency, and comorbidities as predictors of higher total health care costs. Cost-minimization analyses from a public payer perspective provided evidence that implementing a PPMA program for the studied minor ailments could yield cost savings for the Ontario government compared to the usual care model, with savings ranging from $19.05 to$77.38 per patient. One-way sensitivity analyses showed that results were most sensitive to the likelihood of patients receiving care from a pharmacist rather than a physician. In probabilistic sensitivity analyses, the PPMA model proved cost-saving in 100% of the simulations for all 16 minor ailments studied. Conclusion: The results of the thesis research identified the baseline characteristics, health care cost burden, and predictors of total health care costs for patients presenting with minor ailments using Ontario health administrative data. In addition, the cost-minimization analyses conducted from a public payer perspective provided evidence that implementing a PPMA program provided cost-savings for the Ontario government when compared to the usual care model for the studied minor ailments. The results of this research can continue to help shape implementation strategies of a PPMA program in Ontario, Canada