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Recent Submissions

Access status: Open Access ,
Towards Understanding Multilevel Building Navigation for the Blind and Low Vision Individuals
(2026-04-17) Oladipupo, Ridwan; No; Master of Computer Science; Faculty of Computer Science; Received; n/a; No; Rita Orji; Yujie Tang; Rina Wehbe
Over 2.2 billion blind and low vision people globally struggle to navigate multi-level buildings independently. This thesis addresses this problem through three studies. First, we tested low-cost cameras for computer vision applications. Camera C5 per- formed well (0.96 accuracy, $27.99 cost), but all cameras required proper lighting to work. Without light, detection failed completely. Second, we interviewed 20 blind and low vision users about navigating buildings. Most (85%) could not find elevators in unfamiliar buildings without help, and 100% relied on sighted guides, even though they had good navigation skills. The problem was lack of information about where elevators were located. Third, we develop SmartEye, a prototype navigation system achieving 78.96% usability and 91.7% recommendation rates. However, evaluation reveals a critical “last-meter navigation gap”: accurate elevator detection alone fails to ensure successful call button location (r = 0.092). All 12 participants identified hands-free operation as non-negotiable, with guide dog and white cane users reporting physical impossibility of operating handheld devices while maintaining mobility aids. Key findings reveal that effective multi-level navigation requires: (1) hands-free wear- able form factors compatible with existing mobility aids, (2) multimodal audio and haptic feedback, (3) fine-grained directional guidance beyond proximity detection, and (4) adequate environmental lighting. Computer vision can help blind people find elevators in unfamiliar buildings, which is the first step toward accessible multi-level navigation.
Access status: Embargo ,
INTEGRATED BLOOD IMMUNOLOGY FROM VACCINATION TO CRITICAL ILLNESS: BIOMARKERS, MACHINE LEARNING, AND TRANSCRIPTOMIC PATHWAYS
(2026-04-17) Toloue Ostadgavahi, Ali; Yes; Doctor of Philosophy; Department of Microbiology & Immunology; Received; Dr. Ignacio Rubio; Yes; Dr. Christopher Richardson; Dr. Jean Marshall; Dr. Shashi Gujar; Dr. David J. Kelvin
Infection-related critical illness remains a major cause of morbidity and mortality in intensive care units, where COVID-19, bacteremia, sepsis, and septic shock often converge on similar clinical trajectories despite distinct etiologic triggers. Peripheral blood offers a practical window into these systemic responses. However, the molecular programs that distinguish protective immunity from maladaptive inflammation, and early sensing from later tissue injury, remain incompletely resolved. This publication-format thesis investigates blood immune activity along a continuum from controlled antigen exposure in vaccination to dysregulated host response in critical illness, aiming to define shared and syndrome-specific signals that are relevant for risk stratification and treatment. A central challenge in the field is that current clinical labels and single-analyte biomarkers capture hemodynamic consequences of disease better than they capture underlying biology, leading to limited reproducibility and weak guidance on when to apply host-directed interventions. To address this, the thesis integrates complementary blood-based approaches that connect functional humoral immunity, interpretable multiplex biomarker patterns at ICU presentation, and whole-blood transcriptomic pathways measured side by side across major ICU syndromes. By organizing these data into a unified, pathway-centered, time-aware framework, the work tests which programs are conserved across pathogen classes, which are syndrome-specific, and how they evolve with increasing severity. Across the integrated studies, heterologous SARS-CoV-2 vaccination elicits strong binding and neutralizing antibody responses, providing a quantitative benchmark for later blood-signal interpretation. Interpretable machine-learning analyses of ICU biomarker panels identify a small set of stable severity drivers across clinically overlapping infections, with programmed death ligand-1 and myeloperoxidase emerging as conserved indicators linked to worsening multi-organ failure. Comparative whole-blood RNA sequencing of adults with COVID-19, bacteremia, sepsis, and septic shock reveals a shared early core of innate sensing and cytokine activity, with syndrome-specific modulation of complement–coagulation and progressive engagement of metabolic stress, proteostasis, and cytoskeletal remodelling modules as illness severity increases. Together, these findings support a phased model of critical-illness biology and provide a practical scaffold for endotype- and timing-aware biomarker development and therapeutic trials.
Access status: Open Access ,
Conceptualizing Sexual Self-Schemas: A Review of Different Approaches and Their Implications for Understanding Women’s Sexual Function
(2021) Huberman, J. S; Bouchard, K. N.; Wang, G. A.; Rosen, N. O.
Access status: Open Access ,
Effect of Grazing Intensity on Beef Cattle Performance and Predicted Net Greenhouse Gas Emissions
(2026-04-15) Rathgeber, Mackenzie; Not Applicable; Master of Science; Department of Animal Sciences and Aquaculture; Not Applicable; Ed Charmley; Not Applicable; John Duynisveld; Alan Fredeen; David Barrett
A whole farm model, Holos, was used to predict the effects of intensity of rotational grazing on animal performance, soil carbon sequestration, and net carbon equivalence for three seasons (2019-2021). An experiment was conducted on naturalized perennial pasture divided into 12 paddocks (0.8ha), with four replications of three grazing intensity treatments. Dry matter intake (DMI) was measured with three methods. Grazing intensity did not affect animal gain. High grazing intensity had higher DMI determined by pre- and post-grazing samples. Soil organic carbon (SOC) under high grazing intensity exceeded total greenhouse gas (GHG) emissions. Pasture had higher SOC than the typical cropping system. Increased grazing intensity may enhance soil carbon sequestration to offset GHG emissions from grazing beef without decreasing animal performance. Naturalized perennial pasture in the Canadian Maritimes can maintain a higher SOC compared with typical cropping, with implications for farmers wanting to increase their SOC and improve soil health.
Access status: Open Access ,
Combining cosmogenic nuclide depth profiles and in situ 14C to measure erosion-adjusted exposure ages of sedimentary landforms.
(2026-04-14) Paige, Cody; Not Applicable; Master of Science; Department of Earth and Environmental Sciences; Not Applicable; Gary Quintero; Not Applicable; Eric Kirby; Owen Sherwood; John Gosse
In situ cosmogenic ¹⁴C offers a unique window into the recent erosion and burial histories of sedimentary landform surfaces due to its short mean life (ca. 8,223 yr) relative to other terrestrial cosmogenic nuclides (TCNs). This short mean life makes ¹⁴C sensitive to erosion and burial processes over the past 25–30 kyr – timescales that are poorly resolved by longer-lived nuclides such as ¹⁰Be and ³⁶Cl. Here I present a novel approach to estimate erosion rates on late Pleistocene alluvial fan and shoreline surfaces in Panamint Valley, California, by measuring ¹⁴C saturation concentrations in detrital quartz sand from amalgamated sediment samples collected just below the soil mixing zone. Sample locations were guided by soils and geomorphic observations at four sites. I also describe the development and testing of a ¹⁴C extraction line at Dalhousie University, including validation against the known inter-laboratory standard, CRONUS-A. Erosion rate uncertainty improved by up to 50% compared to soils geomorphology-based estimates, providing tighter constraints on ¹⁰Be depth profile exposure ages at the same sites. Comparison of ¹⁴C-derived erosion rates with independent ¹⁰Be and ³⁶Cl depth profile ages suggests that previous field-based erosion rate estimates may have significantly underestimated uncertainty in paleo-erosion histories. These results demonstrate the utility of in situ ¹⁴C saturation measurements as a practical and powerful complement to conventional TCN depth profile dating of alluvial fan surfaces in arid environments, with broader implications for landscape evolution studies in tectonically active regions.
Access status: Open Access ,
Recruitment in Threatened Riverine Species of Nova Scotia: Atlantic Salmon (Salmo salar) and Brook Floater (Alasmidonta varicosa).
(2026-04-15) Roland, Joshua; Not Applicable; Master of Science; Department of Biology; Received; Trevor Avery; Not Applicable; Cindy Breau; Glenn Crossin; Timothy Rawlings; Robert Lennox
Freshwater ecosystems are among the most threatened ecosystems globally, with unionids and salmonids experiencing severe declines. Conservation requires understanding recruitment and identifying where disruptions occur across life stages. This thesis examines recruitment in two freshwater species to inform conservation strategies. Chapter two used radio telemetry to assess Atlantic salmon spawning distribution in the Margaree River, Nova Scotia. Results indicated high residency in lower river reaches before spawning, with use of upper reaches occurring only in late fall (October–November). Chapter three investigated host relationships of brook floater mussels in the East St. Mary’s and Wallace rivers. PCR and sequencing of glochidia from fish gills identified lake chub as a host species in the St. Mary’s River. Additionally, a non-lethal method for sampling glochidia from fish gills was evaluated. Together, these studies address key knowledge gaps in salmon movement ecology and brook floater host associations, supporting improved conservation and management strategies.