19614 research outputs found
Sort by
Brain network similarity using k-cores
Get PDFAutism Spectrum Disorder (ASD) is extensively studied by medical practitioners, health researchers, and educators. ASD symptoms appear in early childhood, within the first two years of life, but diagnosing it remains challenging due to its complex and diverse nature. Nevertheless, early diagnosis is crucial for effective intervention. Traditional methods rely on behavioral observations, while modern approaches involve applying machine learning (ML) to brain networks derived from fMRI scans. Limited explainability of these advanced techniques poses a significant challenge in gaining clinician’s trust.
This thesis builds on recent works that design explainable approaches for ASD diagnosis from fMRI data preprocessed as graphs. Our research makes three key contributions. Firstly, we demonstrate that a simple approach based on viewing graphs as tables and using tabular data classifiers can achieve the same performance as state-of-art, explainable graph theoretic methods. Secondly, we provide evidence that by adding higher-order connectivity information as attributes does not improve their performance. Most importantly, we show why the classification of brain networks is challenging by demonstrating the similarity between graphs belonging to individuals with ASD and those without, using a novel k-core based approach.Graduat
Distributed empirical risk minimization with differential privacy
Get PDFThis work studies the distributed empirical risk minimization (ERM) problem under differential privacy (DP) constraint. Standard distributed algorithms achieve DP typically by perturbing all local subgradients with noise, leading to significantly degenerated utility. To tackle this issue, we develop a class of private distributed dual averaging (DDA) algorithms, which activates a fraction of nodes to perform optimization. Such subsampling procedure provably amplifies the DP guarantee, thereby achieving an equivalent level of DP with reduced noise. We prove that the proposed algorithms have utility loss comparable to centralized private algorithms for both general and strongly convex problems. When removing the noise, our algorithm attains the optimal O(1/t) convergence for non-smooth stochastic optimization. Finally, experimental results on two benchmark datasets are given to verify the effectiveness of the proposed algorithms.FacultyReviewe
"To do so in a patient-centred way is not particularly lucrative": The effects of neoliberal health care on PrEP implementation and delivery
Get PDFBackground: HIV pre-exposure prophylaxis (PrEP) is a highly effective biomedical intervention used by HIV-negative people to prevent HIV acquisition. Despite increased use of PrEP worldwide, several barriers to PrEP implementation have resulted in insufficient uptake, inadequate adherence, and frequent discontinuation. Our objective was to interrogate the social, political, and economic conditions shaping PrEP implementation and delivery among gay, bisexual, queer and other men who have sex with men (GBQM) in Ontario, Canada.
Methods: Six focus groups and three interviews with 20 stakeholders in Ontario (e.g., healthcare professionals, clinicians, community-based organization staff, and government staff) were conducted between July and October 2021. Participants were asked about the personal, workplace, and structural factors shaping PrEP delivery strategies for GBQM. Transcripts were analyzed using reflexive thematic analysis informed by the political economy of PrEP and employed a critique of neoliberalism.
Results: Participants critiqued the problematic arrangements of the current healthcare system in Canada. Neoliberal governmentality and policies have resulted in inequitable PrEP care by establishing funding structures prioritizing profit and requiring patients and providers to function as individual entrepreneurs. Consequently, healthcare disparities are compounded for marginalized peoples who lack the resources and capacity to navigate existing healthcare systems. Participants identified several pathways to improve the implementation of PrEP, including greater institutional and governmental supports for PrEP and healthcare, leveraging communities and collaboration, and moving beyond risk-based health frameworks.
Conclusion: Socio-political-economic changes reflecting post-neoliberal principles are needed to overcome existing barriers to PrEP care, and sexual and reproductive healthcare more broadly.This work was supported by the Canadian Institute of Health Research (no. CTW 155346). D.G. was supported by a Tier 2 Canada Research Chair in Sexual and Gender Minority Health. N.J.L. was supported by the Michael Smith Foundation for Health Research Scholar Award (no. 16863). D.H.S.T. was supported by a Tier 2 Canada Research Chair in HIV Prevention and STI Research.FacultyReviewe
National Sexualism: German History, Identity, and Sexuality in the Political Spectacle of Rammstein
No full textThis project intends to situate the hypersexuality of the German Neue Deutsche Härte group ‘Rammstein’ in the context of the vivid and graphic connections they make between German identity and sexuality in German history and cultural politics. Rammstein’s work includes satirical representations of German history and politics including imperialism, militarism, and the Nazi and East German regimes. Along with obvious historical content, the band often employs sexually explicit aesthetics and themes. Taken in the context of Rammstein’s politically charged works and satirical intent, the implicit association of Nazism with German identity, and larger cultural associations of Nazism with sexual deviancy and sadomasochism, Rammstein’s hypersexuality may simultaneously acknowledge the significance of sexuality in German history, politics, and identity, as well as critique associations of German identity with Nazism and aberrant sexuality.Jamie Cassels Undergraduate Research Awards (JCURA)UndergraduateReviewe
A microfluidics device integrated with Surface Enhanced Raman Spectroscopy (SERS) for characterizing microplastics in aqueous samples
Get PDFMicroplastic contamination is an emerging contaminant and concern that can be found all over the planet. These microplastics are often very tiny in size; therefore, they can readily pass though bedrock and infiltrate water bodies such as rivers, lakes, and seas. Whenever such environmental contamination occurs, the first step in order to address the issue is to characterize the contamination in order to define its origin. This project proposes a design of a microfluidic chip, which is integrated with a Surface Enhanced Raman Spectrometer to characterize microplastic particles in various aqueous solutions such as water. The proposed design is capable of sorting and collecting microplastics based on their size without any need for a membrane. It also has a flat architecture, which makes it easy to manufacture at a reasonable cost. SolidWorks was used for the computer aided design (CAD) of the microfluidic chip and COMSOL Multiphysics was utilized for computer aided engineering (CAE) calculation to verify the design. According to the calculations, this microfluidic chip is capable of size-based sorting of microplastics.Graduat
Neuronal computations supporting direction selectivity in the mouse retina
No full textBy the time visual information leaves the eye, it has already passed through multiple layers of neurons organized into feature-selective circuits that work to distill the analogue light signal received by photoreceptors down into diverse spike rate codes in the ganglion cells of the retina, whose axons make up the optic nerve. Taking advantage of the accessibility of the retina relative to the rest of the brain, dissecting these circuits provides great opportunities for the study of neuronal computations. One such circuit is centred around the direction-selective ganglion cell, which spikes robustly when objects move through their receptive field in particular directions and weakly or not at all in the opposite directions owing to inhibition from presynaptic starburst amacrine cells. This is supported by multiple complementary and redundant computations, both in the presynaptic starburst amacrine cells and postsynaptically in the DSGCs. In this thesis, I use computational modelling methods to complement and formalize theories based on empirical studies of these directional mechanisms as well as to form new predictions at the edge of our current understanding of the circuit.
I start by modelling the "space-time wiring" directional mechanism involving the systematic distribution of kinetically distinct bipolar cell inputs along starburst amacrine cell dendrites using physiologically derived bipolar release transients for the first time. Then, moving downstream, I demonstrate how the asymmetric wiring of starburst dendrites to DSGCs is sufficient to drive DS spiking, even in the absence of directional release of neurotransmitters from starbursts. After exploring two mechanisms generating direction-selective responses in DSGCs, I focus on improving our understanding of how the non-directional glutamatergic and cholinergic sources of excitation to DSGC dendrites support the reliable computation of direction. I show that the mediation of glutamatergic inputs by voltage-dependent NMDA receptors at low-contrasts enables a context-dependent switch between modes of neuronal arithmetic: nearly flat addition over contrast and tuning-preserving multiplication over direction. Finally, I examine how the multi-directed corelease of acetylcholine alongside GABA from starbursts means that the dominant excitation to DSGCs is highly spatiotemporally correlated with inhibition in the null directions, ensuring reliable suppression of spiking. Overall, this research highlights multiple examples of how circuit structure and function work together to support consistent neuronal computations over space and time.Graduate2025-05-0
Patterns of service utilization across the full continuum of care: Using patient journeys to assess disparities in access to health services
No full textHealthcare organizations have a contractual obligation to the public to address population-level inequities to health services access and shed light on them. Various studies have focused on achieving equitable access to healthcare services for vulnerable patients. However, these studies do not provide a nuanced perspective based on the local reality across the full continuum of care. In previous work, graph topology was used to provide visual depictions of the dynamics of patients’ movement across a complex healthcare system. Using patients’ encounters data represented as a graph, this study expands on previous work and proposes a methodology to identify and quantify cohort-specific disparities in accessing healthcare services across the continuum of care. The result has demonstrated that a more nuanced approach to assessing access-to-care disparity is doable using patients’ patterns of service utilization from a longitudinal cross-continuum healthcare dataset. The proposed method can be used as part of a toolkit to support healthcare organizations that wish to structure their services to provide better care to their vulnerable populations based on the local realities. This provides a first step in addressing inequities for vulnerable patients in accessing healthcare services. However, additional steps need to be considered to fully address these inequities.FacultyReviewe
Exploring the experiences of non-traditional military spouses concerning the impact the Canadian Armed Forces has on their careers and lives
No full textPolicies concerning Canadian military families established by the Government of Canada (GoC) and Department of National Defence (DND) have been described as ingraining traditional family constructs. However, demographic transformations away from the traditional family among the Canadian Armed Forces (CAF) highlight the importance of having an accurate view of the demographics and experiences of all manner of Canadian military families and spouses. This study explored the experiences of Canadian, male non-traditional military spouses concerning the CAF’s impact on their careers and lives. It shed light on an understudied sub-set of the military spouse community and their unique experiences. The findings include limited negative impacts on their careers as a result of being a military spouse, plus a shared ownership among domestic division of labour between them and their spouse in the military. In exploring this under-studied population, this study highlights the need to understand and account for the diverse spectrum of military families and spouses, and their realities and needs vis-à-vis the Canadian military.Graduat
Legal design in action: From complex to clear with AI-assisted information design and plain language
No full textClarity is now more important than ever. Legal Design in Action is about transforming complex information into clear, accessible communication for all. This session shows how AI-assisted information design and plain language can be used to simplify contracts and legal content. We will share practical examples, tools and methods for making information understandable and user-friendly, so that everyone can engage with it more effectively.UVic Graduate Student Law & Society Research GroupFacultyUnreviewe
UVic Convocation June 14, 2024 – 10:00 am
No full textStudents from the Faculties of Graduate Studies, Fine Arts and Science.UndergraduateUnreviewe