VictorJuiz/thesis huggingface dataset:
Seasonal Variation of Brain Size and Structure in a Freshwater Top Predator
Keywords: Behavior
Brain Size
Flexability
Seasonal
Telemetry
Winter

Teleost fishes occupy a range of ecosystem and habitat types subject to large seasonal fluctuations. Strategies for surviving theses seasonal environments can vary widely and are commonly accompanied by variation in brain structure. However, our understanding of how predictable changes in behavior across seasons shape, or are shaped by, the nervous system is limited. Here I investigate how patterns in the brain size and brain region sizes of lake trout (Salvelinus namaycush) coincide with seasonal changes in habitat and behavior using Generalized Linear Models (GLMs) and bioacoustic telemetry. There was significant seasonal variation in whole brain size, as well as the size of some regions, which coincided with movement of lake trout between nearshore and offshore habitats. Successful completion of annual life history events (i.e., reproduction, habitat use, and diet shifts) could therefore be supported by seasonally responsive brain size flexibility that allows for a cognitive capacity more tailored to different parts of the year.
Establishing a Mechanistic Link Between Synucleinopathy and Rapid Eye Movement Sleep Behaviour Disorder
Keywords: REM sleep
REM sleep behaviour disorder
synucleinopathy
α-synuclein

REM sleep behavior disorder (RBD) is characterized by REM sleep without muscle atonia. Ninety percent of RBD cases convert into synucleinopathies within 15 years. Synucleinopathies are characterized by α-synuclein aggregates and neurodegeneration. In patients with RBD, α-synuclein aggregates and neurodegeneration affect REM sleep atonia generating brain areas, including the sublaterodorsal tegmental nucleus (SLD) and ventromedial medulla (vmM). Disrupting glutamatergic SLD neurons and GABA/glycinergic vmM neurons causes RBD-like behaviour. Therefore, α-synuclein pathology may cause RBD by disrupting these nuclei. To test this, α-synuclein was overexpressed in glutamatergic SLD cells and GABA/glycinergic vmM cells and α-synuclein aggregation and neurodegeneration were quantified. α-synuclein overexpression in GABA/glycinergic vmM neurons caused α-synuclein aggregation and neuronal loss. Although α-synuclein overexpression in glutamatergic SLD cells caused aggregation, it did not cause neuronal loss. This project provides an animal model of RBD in prodromal synucleinopathy and a means to study synucleinopathic neurodegeneration in REM sleep atonia generating nuclei.
Effect of Resveratrol and Implant Surface Topography on Osseointegration under Hyperglycemic Conditions
Keywords: anchorage
diabetes
hyperglycemia
implant
resveratrol
topography

Chronic hyperglycemia compromises bone structure and may contribute to dental implant failures. Previous studies show that topographically complex implant surfaces enhance bone-implant anchorage compromised by hyperglycemia. Furthermore, resveratrol (RSV) is a potent antioxidant that counteracts the effects of hyperglycemia. The influence of two implant surface profiles (micro- and nanotopographically complex) and RSV administration on osseointegration in hyperglycemic bone was investigated. 240 custom-designed threaded implants were inserted in the proximal tibiae of 120 hyperglycemic Wistar rats. Rats were randomized to receiving weekly subcutaneous resveratrol or propylene glycol injections for a maximum of 4 weeks. Implants then underwent reverse-torque mechanical testing at timepoints between 5 and 84 days. Nanotopographic implants significantly enhanced bone-implant anchorage during implant osseointegration, which transpires within 28 days post-implantation, while resveratrol significantly increased bone-implant anchorage at 84 days, indicating an effect on bone remodelling. This likely occurred due to an influence of RSV on tibial longitudinal growth.
Exercise as an Alternative Depression Treatment: Perspectives and Practices of Canadian Post-secondary Mental Health Care Providers
Keywords: Alternative treatment
Depression
Exercise
Mental health
Physical activity
Post-secondary student

Post-secondary campuses are experiencing challenges with increasing reports of depression symptoms among students. Exercise is an evidence-based treatment for depression, and prescriptions initiated by mental health care providers (MHCPs) could improve uptake to exercise as a treatment. Campuses provide recreation facilities and exercise programs that could be used to support prescription practices, yet the exercise prescription practices among on-campus MHCPs are currently unknown. The purpose of this mixed methods research was to explore post-secondary MHCPs’ practices and beliefs towards prescribing exercise for depression. Participants (N = 153) completed a self-report questionnaire to assess exercise prescription practices, beliefs, and theoretical determinants of prescription practices. Semi-structured interviews (N =12) were conducted to provide contextual details. Based on the integration of the findings, favourable perceptions towards exercise were reported and results provide implications for developing theory-informed resources and training opportunities to leverage on-campus exercise programs as an alternative depression treatment approach.
The Development and Assessment of a Measure of the Quality of Preventive Oral Health Services for First Nations Communities
Keywords: Indigenous
Measurement
Preventive dentistry
Quality of care

Indigenous populations face inequities in oral health compared to the Canadian population. Prevention is key in reducing this gap. This thesis develops and assesses the sensibility and initial validity of a novel instrument for preventive oral health care delivery to Indigenous communities in Canada. Using a mixed-methods sequential approach and concept mapping methodology, the resulting Quality Preventive Oral Health Services for Indigenous Communities (QPOHSIC) scale contains 53 items organized into 7 domains, which present new themes that are not included in previous measures of oral health care delivery, while maintaining themes captured by frameworks and measurements of quality oral health services. The QPOHSIC demonstrated excellent sensibility. Initial construct validity supports that the QPOHSIC measures dental satisfaction, with additional measures of quality pertaining to Indigenous peoples that do not exist in other dental satisfaction measures. Further reliability and validity testing will be performed to complete psychometric assessment of the QPOHSIC scale.
Alpha- and Beta-diversity of Amphibians and Reptiles in Ontario
Keywords: Alpha-diversity
Amphibians
Beta-diversity
Ontario
Reptiles

Reptiles and amphibians are experiencing a global decline. Anthropogenic factors (habitat loss and climate change) are among the many forces causing such decline. At a regional scale, understanding the drivers of amphibian and reptile diversity may be important in the establishment of protected areas. My study leveraged data from the Ontario Reptile and Amphibian Atlas, a citizen science initiative of amphibian and reptile presence data, to uncover the regional-scale drivers of alpha- and beta-diversity of amphibians and reptiles in Ontario. Using univariate and multivariate regression trees, I found that temperature, agriculture, and road density were most strongly associated with alpha- and beta-diversity. My work emphasizes that amphibian and reptile diversity is greatest in southern and central Ontario, where human density is also highest. Future research should examine temporal changes in diversity while accounting for variation in sampling intensity, in order to recommend areas of conservation for wildlife corridors.
Optimization of Hydrodynamics in Full-scale Multi-cassette Flat Sheet Membrane Bioreactors using Computational Fluid Dynamics Modeling
Keywords: computational fluid dynamics
flat-sheet
full-scale MBR
hydrodynamics
membrane bioreactor
porous medium

The porous medium approach has been used to study hydrodynamics in hollow-fiber (HF) membrane bioreactors (MBR), and often a single MBR component was considered. This study aims to expand the application of the porous medium approach to a flat-sheet (FS) configuration and explore the use of computational fluid dynamics (CFD) on optimizing the global hydrodynamics in full-scale multi-cassette FS MBR tanks. The present work first developed a numerical calibration method of the porous parameters for FS membranes. The results suggested that the two-phase flow should be used, and the viscous loss term should not be omitted. Next, three-dimensional CFD models of full-scale FS MBR tanks were developed. The results showed that modifying the tank geometry could be a more efficient option to optimize the flow distribution across the whole tank. In addition, for the first time, the capability and limitation of the porous medium approach were discussed.
The Functional Properties of Inhibitory Neurons in the Brainstem Circuit Mediating the Optokinetic Reflex
Keywords: inhibition
neuron
not-dtn
optogenetics
optokinetic reflex
visual

Reflexes are ideal systems to study how sensory information mediates behavior. For instance, the optokinetic reflex (OKR) is an oculomotor behaviour critical for stable vision. The OKR is driven by the brainstem accessory optic system (AOS), containing neurons encoding the information about the visual field. The AOS neurons are genetically and functionally diverse. However, it remains unknown whether genetically defined AOS populations, such as inhibitory neurons, encode different information in the AOS. By paring in vivo electrophysiology with optogenetic tagging, I studied the spatial frequency and direction selectivity of AOS inhibitory neurons. I found that inhibitory AOS neurons encode lower spatial frequencies and are less direction selective, shedding light on the roles of inhibitory neurons in the OKR.
Implementation of a Kinase-Phosphatase Redox Cycling Pathway to Improve D-Xylose Fermentation in Engineered Saccharomyces cerevisiae
Keywords: Cofactor engineering
Metabolic engineering
NADH kinase
NADP phosphatase
Saccharomyces cerevisiae
Xylose utilization

Unbalanced redox cofactor levels are responsible for low xylose metabolism in Saccharomyces cerevisiae. The NADPH-preferring xylose reductase (XR) and NAD-dependent xylitol dehydrogenase (XDH) enzymes usually expressed in S. cerevisiae have conflicting cofactor requirements. Accordingly, S. cerevisiae produces more xylitol than ethanol, the desired product. This is especially true anaerobically. In our work, we aimed to rebalance the cofactors using a kinase-phosphatase cycling (KPC) pathway featuring NADH kinase (NADHK) and NADP phosphatase (NADPase). In silico, KPC maximized ethanol output at any XR cofactor ratio and under most oxygen conditions. In vivo, NADPase accentuated the redox issues and inhibited growth. Synergistic activity of NADPase and ScUTR1 NADHK helped restore growth and increase xylose utilization, while POS5Δ17 NADHK offered an additional negative contribution. NADPase and ScUTR1 did not lead to growth improvement with respect to the background. We concluded that benefit from KPC activity relies on the optimization of the NADPase/NADHK flux ratio.
Development and Application of Sampling and Extraction Methods for Microplastics in Drinking Water
Keywords: Drinking Water
Methods
Microplastic
QA/QC

To-date, no standardized methods have been proposed for analyzing microplastics in drinking waters. This study assessed known methods to collect and extract microplastics from treated drinking waters and identified two common limitations: use of insufficient water, and lack of method recovery assessment. In response, this study developed an in-line filtration method, which improved accuracy when compared to in-laboratory filtration methods. In-line filtration was shown to have higher recoveries for the reference microplastics examined (+37% for PVC fragments, +23% for PET fragments, +22% for nylon fibers and +7% for PET fibers) and a greater potential to reduce microplastic contamination. The filtration capacity of in-line filtration method was observed to exceed 350 L of treated water. Application of in-line filtration was validated using ultrafiltration (UF) influent and effluent from two full-scale drinking water treatment facilities. UF represents an effective technology which is capable of removing ~95% of microplastics from drinking water.
A Weakly Supervised Framework For the Generation of Instance Segmentation Labels of Contextual Information
Keywords: Environment Context Identification
Robot Navigation and Exploration
Segmentation and Labeling
Weakly Supervised Learning for Robots

This thesis presents a novel Weakly Supervised Mask Data Distillation technique, WeSuperMaDD, to generate Pseudo Segmentation Labels (PSLs) to automate the process of creating image segmentation labels typically created by human annotators. WeSuperMaDD uniquely generates PSLs using learned image features extracted by Convolutional Neural Networks (CNNs) not trained for image segmentation for datasets that are not diverse. WeSuperMaDD introduces a mask refinement system that automatically searches for the PSL with the fewest foreground pixels that satisfies cost constraints. WeSuperMaDD was validated using scene text detection datasets. WeSuperMaDD was found to produce PSLs with higher segmentation accuracy than existing weakly supervised approaches, and comparable accuracy to the state-of-the-art semi-supervised text PSL generation method without requiring fully labeled data. When PSLs generated by WeSuperMaDD were used to train a CNN for context segmentation, improvements in segmentation accuracy in comparison to a CNN trained using Naive PSLs were found.
Teaching Educators About Acquired Brain Injury: A Usability Study Evaluating the Teach-ABI Module
Keywords: acquired brain injury
online module
pediatric
school-based rehabilitation
teacher training
usability study

Acquired brain injury (ABI) is a leading cause of death and disability in children, yet it is a “silent voice” in the Ontario education system and Ontario educators do not receive any related training. This study examined Ontario educators’ satisfaction with the Teach-ABI module, an innovative, e-Learning module that provides information about ABI, its outcomes, and classroom strategies to support students with ABI. Eight educators engaged in one-on-one usability sessions over Zoom, involving a concurrent think-aloud protocol, task completion and participant observation, completion of the System Usability Scale, and an exit interview. Educators identified no significant usability issues with the module and were very satisfied with its content, design, and navigation. Results also revealed that educators were very engaged with the content and felt that it increased their knowledge of ABI. The implications of this study on the development of the Teach-ABI module and future research are discussed.
Metals in Particulate Matter and Deciduous Teeth
Keywords: Deciduous teeth
Metal exposure
Metals
PM2.5

Numerous studies have linked airborne metal exposure to adverse health outcomes. Inter-related characteristics of metals were investigated to gain a better understanding of metal exposure in Toronto including the metal composition of size-resolved road dust particles, potentially bioavailable fractions of metals (water-soluble metals) in PM2.5, spatial variability of PM2.5-bound metal concentrations, and the use of deciduous teeth as a novel biospecimen to reconstruct metal exposure timing. High crustal element content and low intrinsic toxicity were found for road dust particles. Local emissions and possible atmospheric processing were found to affect levels of water-soluble Fe, Cu and Mn in PM2.5. Land-Use Regression modelling of Fe, Cu, Ba, Mn, Zn and Pb in PM2.5 revealed different spatial patterns across Toronto. Microstructure identification and micro-spatial trace metal concentration measurement of primary teeth were performed to support Toronto children metal exposure studies.
A Systematized Review of Youth Mental Health Courts: An Evaluation of the Courts' Operations and Outcomes
Keywords: Court
Mental Health
Program Operations
Program Outcomes
Recidivism
Youth

In this study I reviewed the Canadian and international published literature examining youth mental health courts to provide an overview of their processes, mechanisms of change, and outcomes. A systematized literature review was conducted using the PRISMA-ScR checklist as a guideline following a search of PsychINFO, ERIC, ASSIA, MEDLINE, Sociological Abstracts, Social Services Abstracts, Criminal Justice Abstracts with Full Text, and Child and Adolescent Studies databases. Inclusion criteria stipulated that studies be original research, and examine at least one aspect of the courts’ operations or outcomes. Twenty articles satisfied inclusion criteria. Results showed considerable similarities among intake, referral and case monitoring procedures across courts, and recidivism outcomes. Youth reported courts to be collaborative and supportive, with stakeholders reporting reduced case processing times, improved access to treatment services and reduced recidivism. I highlight findings on operations and outcomes of youth mental health courts that have important implications for policy and practice.
Anomaly Detection for Cybersecurity Attacks on NetFlow Data
Keywords: anomaly detection
cybersecurity
machine learning
NetFlow

Cybersecurity has become an increasingly important topic in recent years, as concepts such as cloud computing are becoming more and more popular. In this thesis, we will investigate various techniques for detecting cybersecurity attacks using data from NetFlow routers. We will investigate popular techniques such as neural networks and autoencoders and more recent techniques including graph neural networks and variational autoencoders. Our particular experiment shows that binary classfiers such as feed forward neural networks (FNN) work better than one-class classifers such as autoencoders and variational autoencoders. We also found that for port scanning attacks, graph neural networks can further improve detection performance.
The Protein Interaction Landscapes of the Apicomplexan Parasites Toxoplasma gondii and Plasmodium falciparum
Keywords: Plasmodium falciparum
Protein protein interaction
Toxoplasma gondii

Apicomplexan parasites, Toxoplasma gondii and Plasmodium falciparum, represent a significant burden to human health. With growing resistance to frontline drugs, new therapeutics are needed to combat these parasites. Their lifecycles are driven by the proteome of its unique cellular architecture: much of which is not fully resolved or characterized. Here we seek to gain insight into the global organization of proteins and identify novel protein complexes by generating high confidence maps of protein interactions in both organisms. This thesis evaluates the quality of these networks by rigorous benchmarking with available biological datasets. Predicted protein complexes successfully recapitulate experimentally characterized complexes from literature and predict novel complexes, including novel mitochondrial and apicomplexan-specific organelle localized complexes. These analyses identify novel components to parasitic pathways, such as host invasion and host interactions. In addition, these networks provide a scaffolding platform for the apicomplexan research community to integrate genomic-scale datasets and generate testable hypotheses.
Dual Photoredox/HAT Chemistry in Carbohydrate Functionalization
Keywords: Anomeric
C-H Functionalization
Carbohydrate
HAT
Photoredox
Spin-center shift

Chemical synthesis of carbohydrate derivatives has attracted much attention due to their prevalence in natural products. The methods for the derivatization of carbohydrate monomers are, however, still mainly focused on the functionalization of hydroxyl groups rather than the carbon-backbone. This thesis describes the exploration of a method for the regioselective C-H alkylation of the anomeric position of 1,2-unprotected carbohydrate diols using hydrogen-atom transfer (HAT)/photoredox chemistry and borinic acid catalysis. Initial experiments yielded mixtures of alkylated products, culminating in the investigation of reaction kinetics and stability of radical intermediates by computational analysis. A second research direction aimed at the transformation of 2-O-acylated pyranosides to 3-keto-2-deoxypyranosides using another HAT/photoredox system is also described. These products are suggested to arise by hydrogenatom abstraction at the C3-position of the pyranoside, followed by C2-O bond cleavage via spincenter shift. Compatibility with variously configured mono-acylated substrates suggest wide applicability for the preparation of rare, deoxygenated carbohydrates.
Comparing the Oxidative Potential of Fine Ambient Particulate Matter Across Airsheds in Canada
Keywords: Canada
OPERA
Oxidative Burden
Oxidative Potential
PM2.5

Oxidative potential (OP) and oxidative burden (OB) are being explored as more health-relevant metrics for assessing the risk of particulate matter. Correlations with different metals have been reported, although the findings are often conflicting, and thus not readily generalizable across locations or airsheds. Approximately 1000 PM2.5 samples, collected from June 2016 until December 2018 in forty cities across Canada, were analyzed using three standardized acellular assays: ascorbate (AA), glutathione (GSH) and dithiothreitol (DTT). Linear and multilinear correlations analyses revealed that different metals were influencing OP and OB to different degrees across the airsheds. In particular, OB values for all three assays were associated with Cu and Fe, and in addition, OBAA with S and K and OBGSH with K. The highest OP and OB values were seen in the East Central airshed, while the lowest were in the Southern Atlantic and Northern airsheds. AA and DTT activity are associated with coal combustion and combustion emissions while GSH activity is associated with anthropogenic metals.
Safety in Construction: Connecting Safety Climate, Safety Performance, and Leading Indicators
Keywords: Construction management
Leading indicators
Near misses
Safety
Time series analysis

Due to the injury-prone nature of the general construction industry, identifying the sector as the better performer in safety would provide insights on aspects requiring further improvement, and determining the leading indicators of injury can help companies develop preventive measures towards increasing injury reports. The two objectives were achieved into two sub-studies. Based on self-administrated survey data, comparisons on workers’ demographic information, their safety perception, and safety performance were conducted between the nuclear sector and the general construction industry through Mann-Whitney test. The nuclear sectors was found to have better safety performance, and factors where the nuclear sector is the better performer were also identified. Besides, based on a 2019 incident dataset, time-dependent relationships between injuries and near miss events were developed using time series analysis. It was found that near miss and physical injuries are interacting with each other closely with lag-time of 1 or 2 weeks.