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Determinants of long-term SARS-CoV-2 immune responses in asymptomatic-to-moderate COVID-19 patients in sub-Saharan Africa
No full textAbstract Background Immune responses after SARS-CoV-2 infection remain poorly characterized in African populations, despite widespread viral transmission and proportionally lower COVID-19 severity and mortality than in other regions. We aimed to define the determinants and durability of humoral and cellular immunity in sub-Saharan Africa and to identify immune correlates of protection against reinfection. Methods We conducted a 12-month longitudinal immunological study involving 513 adults with asymptomatic or mild-to-moderate COVID-19 enrolled across four sub-Saharan African countries (Ghana, Democratic Republic of Congo, Ethiopia, and Mozambique) during four pandemic waves (2020–2022). We profiled levels of IgA, IgG, and IgM against eight SARS-CoV-2 antigens and neutralizing antibody activity against ancestral and variant strains by Luminex, and antigen-specific T- and B–cell responses by flow cytometry. Immune kinetics, decay, immune escape, and reinfection risk were evaluated alongside the impact of clinical and demographic variables, including prior exposure, epidemic wave, geographic site, treatment allocation, and host factors. Statistical analyses included non-parametric tests (Kruskal–Wallis with Benjamini–Hochberg adjustment), Spearman correlations, logistic regression for reinfection, and mixed-effects models for longitudinal determinants. Results Humoral and cellular immune responses were robust and sustained across participants. Estimated antibody half-lives during the early decay phase exceeded 50 days for IgA and IgG. Higher IgA, IgG, and neutralizing levels were significantly associated with lower odds of reinfection during follow-up. Repurposed COVID-19 treatments showed no measurable impact on immune responses. Prior infection and vaccination were the main determinants of antibody magnitude and persistence, greatly surpassing the effects of age, sex, symptoms, and comorbidities. Antibody levels also varied significantly by epidemic wave and site, higher in later waves and, across sites, generally higher in Ethiopia and lower in DRC. Comorbidities were primarily associated with increased SARS-CoV-2–specific T-cell activation. Strong correlations were observed between binding and neutralizing antibodies, and variant-specific immune escape was confirmed for Beta, Gamma, and Omicron. Conclusions This multi-country study provides a comprehensive characterization of SARS-CoV-2 humoral and cellular immune responses in African cohorts and identifies prior exposure and local epidemiological context as the main determinants of immune magnitude, durability, and protection, outweighing other host factors
The Niitoyis Method: Contemporary Indigenous Dramaturgy Rooted in Blackfoot Oral Culture and Spiritual Creation.
No full textThe thesis presents the Niitoyis Method, a Blackfoot dramaturgical framework grounded in ceremony, knowledge, and Siksikaitsitapi cosmology. This work presents Blackfoot knowledge as a creative system rooted in oral tradition, community ties, and lived experience rather than as a subset of western theatre. The Niitoyis, the lodge, serves as both the conceptual and structural model for this method, shaping how story, language, and ceremonial process inform artistic creation. Part A responds to the limitations of colonial ethnography by restoring Blackfoot metaphysics, Land, law, and oral history as the foundations for dramaturgical structure. Through creation stories, bundles, and ceremonial practice, this section outlines how prayer, protocol, and relational governance function as performance and pedagogy. Part B applies the Niitoyis Method through an oral presentation rooted in Blackfoot protocol, emphasizing teachings that require embodied and relational transmission. Together, these sections position the Niitoyis Method as a distinct Blackfoot lodge within the broader circle of Indigenous dramaturgies across Turtle Island, affirming it as a living, culturally grounded methodology for future Indigenous creators
RoboHaptics: Designing Haptic Interactions for Lower Body with Quadruped Robot Dogs
No full textExtended Reality (XR) systems now offer high-quality visual and auditory immersion, yet their support for haptic feedback remains uneven, especially for the legs and feet. Many VR experiences visually depict lower-body events such as impacts, boundaries, and guidance, but provide little or no corresponding physical sensation. This thesis investigates whether a commercially available quadruped robot can be treated as a mobile, off-body “lower-body haptic instrument” rather than solely as a locomotion platform. We introduce RoboHaptics, a haptic toolkit that turns quadruped motion into programmable haptic prim-itives for the lower body. RoboHaptics abstracts low-level control into six parameterized primitives—Knock, Tap, Double Tap, Touch, Press, and Push—which can be configured by robot posture, approach trajectory, contact footprint, and target body location. Two technical studies characterize the capability envelope of these primitives. A load-cell experiment shows that different postures can safely deliver approximately 3–28 N of contact forces, within ranges suitable for repeated lower-body stimulation. A mannequin-based experi-ment quantifies reachability around the legs and demonstrates millimetre-scale precision and accuracy across common targets, confirming that the quadruped can reliably “hit” intended locations. Building on this characterization, two user studies investigate how quadruped-mediated lower-body hap-tics are experienced and interpreted. In VR scenarios such as a fence, a rolling ball, and a table edge, participants rated the comfort, realism, and immersion of RoboHaptics feedback in comparison to ground-truth physical proxies. A second study probes the six primitives as a tactile vocabulary, revealing consistent mappings from temporal–force profiles to social meanings including alerts, boundaries, assistance, and re-assurance. Together, this thesis establishes quadruped robots as a viable lower-body haptic instrument for XR, contributing a design space, authoring toolkit, empirical characterization, and design guidelines that connect robot movement choices to perceived safety, legibility, and immersion
The Use of Telepathology in Veterinary Medical Education: A Scoping Review Protocol
No full textScoping review PROTOCOL about the role of telepathology in veterinary medical education.Background: Telepathology, the remote interpretation of pathology images, has gained traction in veterinary medicine with advances in digital pathology and whole-slide imaging. In veterinary education, telepathology offers unique opportunities to enhance learning by providing students and trainees with remote access to digitized histologic slides, virtual microscopy platforms, and expert-guided case discussions. This technology can overcome traditional barriers associated with physical slide distribution, facilitate collaborative learning across institutions, and support competency-based training in diagnostic pathology. Despite the potential to enhance teaching and learning, the adoption and effectiveness of telepathology in veterinary education remains poorly characterized. This scoping review will map current evidence on telepathology in veterinary education to identify practices, outcomes, and research gaps.
Objectives: The primary objective of this scoping review is to map and synthesize the existing literature on the use of telepathology in veterinary medical education.
Eligibility criteria: Peer reviewed journal articles and grey literature in the English language and published after 2000 will be included in the study. It must be relevant to telepathology in veterinary medical education. Literature about radiology, bacteriology, virology, parasitology, toxicology, human medicine or human medical education will be excluded.
Sources of evidence: Searches will be conducted in MEDLINE, Embase, CINAHL, CAB Abstracts and Web of Science. Websites from veterinary pathology specialty colleges (ACVP, ECVP, ASVCP) and affiliated pathology residency training programs will be searched for grey literature.
Charting methods: Data charting will include bibliographical information (author(s), year of publication, country, source type), study characteristics (design, educational context, discipline), telepathology application (mode, technology/platform, communication method), education purpose (teaching, assessment, continuing education, integration with other technologies), reported outcomes (learning effectiveness, user experience, barrier, facilitators), gaps and recommendations
RPAS-Based Mapping of Peatland Microtopography and Hydrology: A Case Study of Repeated Seismic Line Disturbance in Northern Alberta
No full textPeatlands are ecologically important ecosystems in Alberta’s boreal region, yet they are extensively dissected by seismic lines created for natural resource exploration. These linear disturbances alter peatland microtopography and hydrology by compacting the surface, altering microtopographic variability and elevating water tables. Re-using existing seismic lines is often promoted as a way to minimize new disturbance footprint. However, the long-term consequences of repeated seismic line use in peatlands remain poorly understood. This thesis uses remotely piloted aircraft system (RPAS)–based LiDAR and optical imagery to assess how seismic line properties evolve across different disturbance histories. Four attributes—ground depression, hummock cover, depth to water (DTW), and surface water cover—were quantified on new (created in 2021), old (created in 1996), and re-disturbed (created in 1996, re-cut in 2021) seismic lines, as well as adjacent undisturbed peatland. New disturbances showed uniform depression, minimal hummock cover, and shallow DTW, indicative of recent compaction. Old disturbances exhibited greater heterogeneity, with evidence of partial hummock recovery alongside localized surface degradation. Re-disturbances largely reset surface structure, removing microforms that had re-established over the previous decades and producing wetter, flatter conditions. Overall, these results show that seismic line morphology and hydrology evolve along divergent trajectories over time, and that re-disturbance can substantially delay natural recovery. The compounding effects observed on re-disturbed lines indicate that re-using existing corridors should not automatically be considered a lower-impact strategy in peatlands. RPAS data provide a powerful tool for mapping these fine-scale attributes and can support evidence-based management and restoration decisions in boreal peatlands
A Robust Structure-Aware Arc-Length Parameterization Framework for 3D Lane Reconstruction
No full textAccurate and structurally coherent 3D lane geometry is fundamental for autonomous vehicle (AV) high-definition (HD) mapping, supporting vehicle localization and planning. Lanes form the structural backbone of road geometry, constraining vehicle pose estimation and guiding navigation. For practical deployment, lane representations must maintain geometric structure and positioning fidelity under degraded or uncertain sensing conditions. Conventional 2D-to-3D lane lifting methods struggle under real-world sensing challenges such as sparse returns from the light detection and ranging (LiDAR) sensor, camera calibration drift, and environmental degradation. Learning-based reconstruction approaches can compensate through learned priors but are prone to sensor overfitting and domain shift degradation. This work introduces a geometry-driven lifting approach that reformulates lanes as arc-length-parameterized curves, producing metrically
consistent and structure-reserving 3D polyline representations from monocular 2D detections. This arc-length reparameterization aims to preserve structural coherence under real-world sensing constraints. Sparse LiDAR points are used as depth anchors when available. Depth matches, Random Sample Consensus (RANSAC) plane fitting (on the original point set), camera intrinsics, and the estimated ground surface are fused with structure priors to yield a 3D parametric curve representation of lanes. 2D detected lane anchors are reparametrized as cumulative arc-lengths. A piecewise cubic Hermite interpolating polynomial (PCHIP) maps arc-length to progression along a 3D parametric curve, thus generating 3D lane points and 3D lane structure. The pipeline is modular, lightweight, and non-learning-based, making it suitable for resource-constrained deployments or domains lacking stable priors. Overall, this work establishes arc-length-parameterized geometric lifting as an effective, interpretable, and deployment-ready solution for monocular 3D lane reconstruction, offering strong structural fidelity with minimal sensor requirements and without reliance on learned priors
Leveraging Cultural Capital and Funds of Knowledge for Academic Integration: A Case Study of South Asian International STEM Students at a Canadian University
No full textInternational enrollment at Canadian universities has consistently increased, especially in STEM (Science, Technology, Engineering, and Mathematics) fields, with South Asian students among the fastest-growing groups. While these students bring strong academic backgrounds and diverse cultural insights, institutional integration strategies usually focus on perceived shortcomings rather than on valuing their existing strengths. This qualitative case study explores how South Asian international graduate students in STEM programs manage academic integration at a Canadian university. Using semi-structured interviews and thematic analysis in NVivo, the study views integration as a relational and ongoing process shaped by individual agency, social connections, and institutional recognition. Participants reported initial difficulties with pedagogical differences, communication norms, and unfamiliar academic standards. However, they actively utilized cultural assets, knowledge resources, and community networks to adapt, stay engaged, and build confidence. The findings reveal that academic integration extends beyond individual adjustment and is significantly influenced by institutional practices. Recognizing students’ prior knowledge and cultural experiences nurtures a sense of belonging and the development of STEM identities, while limited opportunities for epistemic inclusion hinder meaningful participation. These dynamics illustrate how integration evolves through interconnected individual, relational, and institutional processes. Ultimately, this study contributes to research on international students in STEM by advocating for an asset-based, relational perspective of integration and highlighting the importance of inclusive pedagogical and institutional practices that promote epistemic justice and shared responsibility in higher education
Investigating the effect of magnetic nanoparticles in partial upgrading of bitumen by ultrasonic irradiation
No full textIn this study, the performance of magnetic and recyclable NiFe₂O₄ nanoparticles for partial bitumen upgrading under ultrasonic irradiation was investigated the synthesis and stability of the catalyst were confirmed through characterization of both freshly synthesized and recycled nanoparticles from experiments conducted using an open low-power probe (ULP) and a closed high-power probe (UHP). Characterization techniques including SEM, IR, EDX, XRD, and VSM confirmed the stability of the nanoparticles after recycling. These nanoparticles facilitated the upgrading process by amplifying the effects of the intense localized energy from ultrasonic cavitation. Ultrasonic “hot spots” provide sufficient energy to initiate the cleavage of strong chemical bonds within bitumen components. In this context, the NiFe₂O₄ catalyst plays a synergistic role by reducing the activation energy required for bond breaking, disrupting interactions between asphaltene molecules, and interacting with heteroatom-containing components in bitumen through its acidic sites. To further enhance radical stabilization and upgrading efficiency, tetralin was used in a minimum amount of 2% (wt.). Tetralin, by donating hydrogen atoms and forming benzyl radicals, prevents radical recombination, promotes the formation of stable lighter hydrocarbons, facilitates the dealkylation process, and contributes to the long-term viscosity stability (up to one month) of the upgraded bitumen. In summary, the UHP system, with its higher power density, reduced the viscosity of a bitumen from 225,000 to ~159,300 mPa·s (29 %). Also, there was 46% and 35% reduction in asphaltene, and sulfur content of bitumen respectively compared to the untreated sample. These results confirm the synergistic effectiveness of NiFe₂O₄ nanoparticles and a hydrogen donor such as tetralin in ultrasonic-assisted upgrading. Conducted under mild reaction conditions, no external heating, moderate temperatures, short reaction times, and atmospheric pressure, the process proved to be both energy-efficient and practical. These findings highlight the potential of this approach as a scalable, and sustainable strategy for heavy oil upgrading through the integration of ultrasonic and catalytic technologies
Conditioned media and extracellular vesicles derived from human Wharton’s jelly mesenchymal stem cells improve the in vitro maturation of immature oocytes in normal and PCOS mouse model
No full textAbstract Background The effects of conditioned medium (CM) and extracellular vesicles (EVs) derived from human Wharton’s jelly mesenchymal stem cells (hWJMSCs) on in vitro maturation (IVM) of immature oocytes in both normal and polycystic ovary syndrome (PCOS)-induced mice were investigated. PCOS was induced in adult female NMRI mice by administering letrozole (90 μg/kg/day) via gavage for one week. Germinal vesicle (GV) oocytes were collected from both PCOS-induced and normal mice, while mature oocytes (MII) were obtained from superovulated normal mice to serve as controls. The experimental groups included 7 groups: Control (MII oocytes), 3 IVM groups (in vitro maturation of GV oocytes): IVM (with simple IVM media), IVM + CM, and IVM + EVs (IVM media supplemented with CM and EVs, respectively), and three PCOS groups (in vitro maturation of GV oocytes from PCOS-induced mice): PCOS IVM (with simple IVM media), PCOS IVM + CM, and PCOS IVM + EVs (IVM media supplemented with CM and EVs, respectively). After IVM was conducted in all groups, mature oocytes were harvested and assessed for maturation rate, morphology, viability, and gene expression profiles of key regulators (CDK1, CCNB1, MAP2K). Developmentally competent oocytes were selected using Brilliant Cresyl Blue staining and then subjected to in vitro maturation with or without CM or EVs supplementation. Nuclear maturation was evaluated via orcein staining, while viability was assessed using Trypan Blue. Morphometric parameters were measured using ImageJ software. Real-time PCR was utilized for the evaluation of gene expression of targeted genes. Results Results demonstrated that in BCB + oocytes, CM and EVs improved the mature oocytes compared to IVM. Oocytes from PCOS-induced mice exhibited reduced maturation and increased degeneration, which were rescued by CM and EV treatment. Gene expression analysis revealed downregulation of MAP2K, CCNB1, and CDK1 in IVM and PCOS IVM groups compared to the control group, while CM supplementation restored their expression. Oocyte diameter and viability were significantly enhanced in IVM + CM compared to IVM (P < 0.05). Conclusions These findings suggest that hWJMSC-derived secretomes, particularly CM, enhance oocyte maturation and quality, offering potential therapeutic benefits for IVM in both normal and PCOS conditions
Insidious systems: a scoping review of Black youth and the criminal justice system in Canada
No full textAbstract Introduction A growing concern within and beyond Black communities is the increasing injustices faced by Black children and youth, especially the indelible injustices imposed in their involvement with the Canadian criminal justice system. This study conducts a scoping review of the existing literature on Black youth involvement with the Canadian criminal justice system. Methods The scoping review followed Arksey and O’Malley’s five step framework and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines. We broadly searched seven databases for studies focusing on Black children and youth (0–30 years) in Canada. This scoping review reports data extracted from 35 criminal-justice related studies. Results Research on Black youth and the criminal justice system in Canada has grown since 2000, with most studies (60%) focusing on Ontario. Findings were categorized by systems (child welfare, education, and health) and their interactions with the criminal justice system. Black youth’s contact with the criminal justice system is an extension of their daily interactions and experiences within other systems, where decisions, actions, and culture are underscored by processes of racial injustice. Conclusions While there is more attention to research on Black youth involvement with the Canadian criminal justice system, more work is needed to understand their experiences at different levels of involvement with the Canadian criminal justice system, in order to guide and advance the development of relevant policies, strategies, and interventions. Focused efforts should be directed at addressing anti-Black racism within Canadian systems, particularly in child welfare, healthcare, and education, due to their deep and troubling connection to the criminal justice system