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A Non-Invasive Approach to Investigating the Intrinsic Cerebrovascular Regulation and Sympathetic Nervous System Using Functional Optical Coherence Tomography (f-OCT)
(2024-05-14) Safarzadeh, Mohammad; Wilson, Richard; Alim, Usman; Gordon, Grant
While cerebral autoregulation and the sympathetic nervous system are crucial for maintaining stable blood flow to the brain, dysfunctions in these systems can lead to severe disorders, including cardiovascular disease and strokes. To enhance future exploration of these phenomena in humans, this thesis investigates retinal and choroidal vasculature changes under hypoxia using functional Optical Coherence Tomography (f-OCT) imaging. The first hypothesis aims to assess cerebrovascular autoregulation through retinal vasculature monitoring, while the second examines sympathetic nervous system activity by observing choroidal vasculature changes, within the White Mountain database. This investigation seeks to enhance tools for monitoring cerebrovascular function and associated diseases. OCT imaging faces challenges like high noise, artifacts, lack of standardization, and assessment difficulties. To address these, two interconnected vascular bed analysis pipelines were used, along with a novel framework named Q-MCDM (Quasi-Monte Carlo Multi Criteria Decision making). Q-MCDM enhances OCT image processing and evaluation, marking a step towards Interpretable AI in healthcare by optimizing design, execution, and trade-offs in image analysis approaches. Using Q-MCDM for the retinal vascular bed, Frangi's algorithm emerged as the optimal choice for segmentation, achieving a Matthews Correlation Coefficient (MCC) of 0.82, Length (LE) of 0.81, and Area (AR) of 0.86. Conversely, in the choroid vascular bed, the ISODATA method yielded the best results with a Dice coefficient of 0.82, Matthews Correlation Coefficient (MCC) of 0.71, and Area (AR) of 0.79. Significant correlations were observed between vessel perfusion density (VPD) and partial O2 pressure, consistently present across best solutions (r value range = -0.701 to -0.663). Distinct behaviors were observed in the choroid vascular bed's layers. The superficial layer showed increased VPD values, potentially indicating vessel dilation due to parasympathetic or intrinsic autoregulation. In contrast, the deep layer exhibited significant constriction in VPD values, possibly linked to sympathetic nervous system activity. Test/retest assessments confirmed the stability of biological response over time, emphasizing the significance of the findings in understanding intrinsic autoregulation and autonomic nervous system through f-OCT.
Item
Open Access
The Virtual Rehearsal Suite: Drama and Performance Approaches for Virtual Reality and Human-Computer Interaction
(2024-05-14) McKendrick, Zachary E. R.; Finn, Patrick; Sharlin, Ehud; Munteanu, Cosmin; Oehlberg, Lora; Viczko, April; Ullyot, Michael
This dissertation explores the intersection of Drama, virtual reality (VR), and Human-Computer Interaction (HCI), examining their parallels and collective impact on shaping immersive digital experiences. Throughout our research, we ask: how can VR support traditional performance practices? And how can we leverage existing performance practices to support wholistic user engagement? From our interdisciplinary position we identify gaps in existing research and offer novel solutions and innovative frameworks for navigating and structuring experiences within VR. In pursuit of answers to our research questions, we contribute C1) Performance-Based Multimodal Methodological Approaches for HCI, and C2) A Demonstration of Interdisciplinary Possibilities to the landscape of HCI VR research. We propose a symbiotic relationship between the user's cognitive engagement and the digital environment's architectural and interaction design can be enhanced through the application of practices and principles from Drama and performance. The practical application of these theoretical constructs is showcased in C3) Thresholding Protocols for Digital State Change, and C4) The Virtual Rehearsal Suite (VRS), an immersive VR environment that supports solo performance training, demonstrating how Drama and performance methodologies can enhance the user's experience, offering tested perspectives and techniques that promote interaction, presence, and embodiment. Starting with our related works, we identify our interdisciplinary position with a foundation that draws from both the academic and artistic communities interested in VR as a domain, research, and performance tool. We then cast a wide net to understand the dimensions of virtual technologies and their impact on user experience with subsequent chapters investigating the layers of reality, immersion, embodiment, performance rituals, and thresholding concepts. Each chapter contributes to the identification of gaps and parallels across research domains and the discussion of how Drama and performance can elevate the understanding and advancement of VR and HCI systems. The dissertation concludes that the confluence of Drama and performance practice with Interaction Design holds the potential to shape the future aesthetics and experiential facets of virtual environments. The embrace of VR as both a tool and a medium for creative expression is positioned as a transformative leap forward in both HCI and Drama, heralding a new era of digital interaction that needs to embrace the full spectrum of human experience for success and longevity. Our work positions actors as interaction specialists, capable of existing in multiple realities at once and providing insightful reflections on their experiences in iterative processes. The VRS study demonstrates this ability, while emphasizing that virtual environments are not merely technological constructs but complex experiential spaces where the physical and digital converge, challenging traditional perceptions of reality. It highlights the importance of centralizing the user as key to creating compelling virtual experiences that con only be achieved through meticulously designed interactions that resonate with the user's sensory and cognitive faculties. Our study underscores the efficacy of VR in supporting actor training with minimal digital interventions, facilitating a seamless transition into and out of VR, enhancing focus during VR engagement, and addressing issues such as VR sickness. It highlights the centralization of the human element as the pivotal factor in VR creation, emphasizing that VR environments should cater to the nuanced spectrum of human emotions, behaviours, and social interactions.
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Open Access
Prevalence, persistence and consequences of microorganisms within oil field environments and mitigation strategies
(2024-05-14) Scheffer, Gabrielle; Hubert, Casey; Gieg, Lisa; Wrighton, Kelly
The deep biosphere is home to an abundance of microorganisms. However, limitations to accessing deep subsurface samples means that very little is known about microorganisms from the marine and terrestrial subsurface. Oil and gas industry technologies, including advancements in hydraulic fracturing and horizontal drilling, have increased access to samples for environmental microbiology, enabling microorganisms inhabiting those ecosystems to be studied. It is now better understood that microorganisms must withstand extreme conditions (high temperatures, high salinities, high pressures and the presence of toxic metals). Furthermore, these “extremophiles” can significantly impact oil production operations both negatively (i.e., reservoir souring) and positively (i.e., reservoir souring control). To date, most microbiology studies of hydraulically fractured hydrocarbon reservoirs have been performed on a limited number of unconventional shale formations in the United States (e.g., the Marcellus Formation) and do not represent the geological conditions in other unconventional formations. This work focuses on less studied unconventional tight formations in the Permian Basin Formation (United States) and the Montney Formation (Canada), as well as a conventional high salinity reservoir in the Gulf of Mexico. While it is known that microorganisms influence the oil and gas operations (souring, corrosion, bioplugging), their provenance remains a debated topic. It is unresolved whether microorganisms are pre-existing deep biosphere residents of unconventional formations or if they are introduced by the oil and gas operations. Results presented in this thesis demonstrate that some microorganisms are found in the Montney Formation prior to industrial intervention, featuring genome-encoded adaptations to the extreme conditions in this reservoir. Introduced microorganisms still play a major role in souring and corrosion, which can be mitigated by other microorganisms through nitrate addition to oil field systems.
Item
Open Access
Local Media and the Olympic Bidding Process: A political economic analysis of Calgary’s 1988 and 2026 Olympic pursuits
(2024-05-14) Halajian, Matthew; Taylor, Gregory; Hiller, Harry; Stowe, Lisa Roxanne
This research project explores how changes to the political economy of the local media industry impact public opinion by analyzing two case studies: Calgary’s successful bid for the 1988 Olympic Winter Games and the city’s failed bid exploration for the 2026 Olympic and Paralympic Winter Games. The Olympic Games embody a melange of social, cultural, political, and economic elements alongside distinct urban, sporting, and media dimensions. I focused on scholarly literature pertaining to 1) the sports-media complex and changes to specific media industries, 2) relevant aspects of the Olympic Games and the Olympic bidding process, and 3) Calgary’s Olympic bid pursuits and how they are situated in the contemporary bidding environment. In this, the sports-media complex encompasses the fundamentally inseparable relationship between the sports and media commercial capitalist industries and their prime commodity: the audience. This study employed qualitative methods, highlighted by the 14 semi- structured one-on-one interviews I conducted with individuals involved in, or experts on, one or both of these case studies; I then performed a thematic analysis and identified five themes. In this paper, I emphasize the second theme: the role of the changing local media industry. This analysis demonstrates that the political economy of the local media in Calgary, particularly the newspaper industry, has decayed dramatically since the late 1970s. With this knowledge, I argue that this decay presents tangible and worrying consequences for the contemporary information landscape and concretely harms the ability of citizens to be adequately informed on matters of public policy.
Item
Open Access
Exploring Markers of Brain-Computer Interface Performance in Children
(2024-05-14) Kim, Vella Shin-Hyung; Kirton, Adam; Abou-Zeid, Hatem; Condliffe, Elizabeth; Kinney-Lang, Eli
For children with severe motor impairments, brain-computer interfaces (BCIs) are a potential life changing solution that provide an alternate means of communication and control. Some BCI users experience difficulties controlling a motor-imagery BCI (MI-BCI), but the unique factors influencing BCI performance in children are largely understudied. This study aimed to build predictive models of BCI performance in typically developing children using EEG correlates, demographic factors, and subjective assessments. We also aimed to explore specific features most predictive of BCI performance in children. Two datasets, DS1 (n=31) and DS2 (n=22) from independent studies comprising of EEG data, demographic information, and subjective assessments from typically-developing children were utilized. Models were trained 15 times, each on different feature subsets from DS1 using Support Vector Machine (SVM) and Random Forest (RF) classifiers, with hyperparameter optimization conducted using a differential genetic particle swarm optimizer. Models were internally (within-distribution) and externally (out-of-distribution using DS2) tested using repeated stratified k-fold cross-validation. We assessed the most commonly selected features for each feature set and the SHapley Additive exPlanations (SHAP) scores of the highest performing models. SVM models trained on EEG features outperformed models trained with all features or non-EEG features. The highest performing model was an SVM model trained on EEG features, with a cross-validation score, internal test score, and external test score of 0.76±0.24, 0.75, and 0.77 respectively. Connectivity and power in the alpha and theta bands were most predictive of BCI performance in our highest performing models. Our investigations provide a tool to predict BCI performance in children, and allow a fuller understanding of the internal factors influencing BCI performance. Predicting BCI performance in children can help to understand when standard BCI paradigms may not work for users and indicate when alternative methods of training may be necessary, ultimately improving the usability of BCIs in children.