VictorJuiz/thesis huggingface dataset:
Assessing Correlation between PM2.5 and Meteorological Variables and Projecting the Impact of Climate Change on PM2.5

This study builds the Statistical Downscaling Model (SDSM), coupled with the Artificial Neural Network (ANN), to identify meteorological variables that show strong influence on the concentrations of fine particulate matter (PM2.5) and to project future PM2.5 concentrations using global climate model in IPCC Fifth Assessment Report (AR5). Toronto and Sarnia, Canada are chosen to study the effects of meteorological influence and climate change on PM2.5, as a comparison of metropolitan and industrial cities. Higher PM2.5 in Summer are detected which is affected by the long range transport of pollutants. Seasonal models are built using ANN in both cities to study the influential predictors in each season, which perform better than annual models with a 10-15% increase in R2 value. The SDSM model projects future PM2.5 under the assumption of constant emissions. Results show that the impact of climate change on PM2.5 is relatively small due to the cancellation of opposite changes caused by predictors.

Keywords: Climate change
Neural Network
PM2.5
Statistical downscaling
Advisor: Gough, William
A Unique Gene Expression Profile to Identify Operationally Tolerant Liver Transplant Recipients

Identification of operationally tolerant liver transplant recipients (TOL) would allow for withdrawal of immunosuppression and potential improvement in long-term graft survival. We investigated the utility of a previously identified pre-clinical gene expression profile to identify TOL. Peripheral blood mononuclear cells (PBMC) were isolated from TOL (N= 4), rejecting liver transplant recipients (REJ, N= 6); liver transplant recipients on minimal immunosuppression (Min IS, N= 29),on standard immunosuppression (Stand IS, N= 24), and healthy live liver donors (HLD, N= 23). Liver biopsies and plasma cytokine levels were also obtained from a subset of patients to compare intra-graft gene expression with gene expression and protein levels in PBMC. All 4 liver transplant recipients who had developed a state of tolerance and were off immunosuppression (TOL) had high co-expression of FGL2 and TIGIT mRNA transcripts in their PBMC in contrast to patients undergoing rejection yielding a potentially useful biomarker panel for operational tolerance.

Keywords: Biomarker
Hepatology
Immunology
Liver Transplant
Tolerance
Transplantation
Advisor: Levy, Gary
Patent Ductus Arteriosus Ligation in Extremely Preterm Infants and Death or Neurodevelopmental Impairment

Objective: Evaluate the association between patent ductus arteriosus (PDA) ligation vs. medical management and neonatal and neurodevelopmental outcomes. Methods: Retrospective cohort study of extremely preterm infants with PDA born between 2006-2012. The primary outcome was death or neurodevelopmental impairment (NDI) at 18-24 months. Secondary outcomes included death, chronic lung disease (CLD), and NDI. Multivariable logistic regression (MLR) analysis and marginal structural models (MSM) were used to adjust for perinatal and postnatal confounders. Results: Of 754 infants with PDA, 184(24%) underwent ligation. Compared with medically treated infants, ligated infants had similar odds of death/NDI (aOR 0.83, 95%CI:0.52-1.32), NDI (aOR 1.27, 95%CI:0.78–2.06), and CLD (aOR 1.36, 95%CI:0.78–2.39), but lower mortality (aOR 0.09, 95%CI:0.04–0.21). Conclusions: PDA ligation is not associated with adverse outcomes and may reduce mortality. Previously reported associations of ligation with increased morbidity are likely due to bias from confounding by indication, rather than a detrimental causal effect of ligation.

Keywords: cerebral palsy
confounding
mortality
neurosensory
NICU
PDA
Advisor: Shah, Prakesh S
The Relationship between Risk, Criminogenic Need, and Recidivism for Indigenous Justice-involved Youth: A Comparative, Mixed-methods Investigation

The Risk-Need-Responsivity framework is widely used in Canada to guide the sentencing and case management of justice-involved youth, but there is little research on its applicability to Indigenous populations. The present study analyzed quantitative data for 70 justice-involved youth, together with qualitative data from frontline service providers, to explore how standardized risk assessment, identification of criminogenic needs, and receipt of need-targeted programming related to recidivism for Indigenous youth compared to non-Indigenous youth. The two groups did not differ on overall level of risk, number of needs, match to services, or recidivism rates. However, Indigenous youth were evaluated as higher risk in the peer and leisure domains, more likely to have needs related to education and leisure, and less likely to receive adequate peer-specific intervention. In both groups, risk assessment predicted recidivism, while match to services predicted days to reoffence. Frontline workers shared information with critical implications for research and practice.

Keywords: Indigenous youth
justice-involved youth
RNR theory
Advisor: Peterson-Badali, Michele
Design of a Rotating Permanent Magnet System for 5-DOF Control of Micro-robots

Recent work in magnetically-actuated micro-scale robots for biomedical and microfluidic applications has resulted in magnetic actuation systems which can remotely command precise five-degree-of-freedom control of magnetic devices. The objective of this work is to evaluate the capabilities and limitations of these existing systems and to provide a more complete understanding regarding the limits of field generation. As part of this study, a novel actuation system composed of an array of rotating permanent magnets with the potential for increased field and gradient strength, and minimal heat generation is presented. The nonlinear control input-output relationship is modeled, a technique to determine the control inputs is developed, and an optimization framework for designing system configurations for targeted applications is shown. A proof-of-concept prototype system is used to demonstrate the feasibility of this type of actuation by performing three standard microrobotic locomotion methods requiring independent control over the applied magnetic fields and forces in three dimensions.

Keywords: 5-DOF
Microrobots
Novel actuation system
Permanent magnet
Untethered
Advisor: Diller, Eric
Addressing the Lexical Quality Hypothesis and Language Comprehension in First and Second Language Learners

This study investigated whether there was evidence to support both the lexical quality hypothesis and simple view of reading in a grade 5 diverse sample of 94 English monolingual speakers (EL1) and 178 English Language Learners (ELL). Latent profile analyses conducted with the language groups together and separately revealed clusters consisting of good comprehenders, poor language, and poor word-level skills, with a fourth cluster of average comprehenders for the ELL group. Support was found for the lexical quality hypothesis as good comprehenders showed strong performance across phonological, orthographic and semantic component skills, while poor comprehenders showed profiles consistent with those of dyslexia or language impairment. In support of the simple view of reading, language comprehension emerged as a distinct deficit for those in the poor language group. Finally, more ELLs were identified as having poor language in the whole sample analysis than when compared only to other ELLs.

Keywords: English language learners
Language comprehension
Lexical quality hypothesis
Reading comprehension
Advisor: Geva, Esther
Control of Lineage Decisions in the Embryonic Kidney by Hedgehog Signalling

Foxd1-expressing cells give rise to stromal components in the mammalian embryonic kidney, and are the major source of myofibroblasts during renal fibrosis. The signalling pathways involved in segregation of the stromal and nephrogenic lineages from their common precursor cells is not fully understood. Previous studies in the Rosenblum lab have shown the role of HH signaling in expansion of cortical stromal gene expression and ureteropelvic junction development. I present a stage-specific role for HH signalling in early renal precursors expressing Sall1 and Osr1 in promoting stromal cell specification without affecting the nephrogenic lineage. Temporal deletion of Ptc1 in Sall1+ and Osr1+ cells results in an early increase in stromal cells, disorganization of the cortical stroma, medullary localization of cortical stromal cells, decreased nephron number, and no change in cell proliferation. Mutant kidneys exhibit UPJ obstruction at birth caused by ectopic cortical stromal cells in an activated state of HH signalling.

Advisor: Rosenblum, Norman D
Parenting by Lying in Childhood Predicts Lying to Parents and Socio-emotional Adjustments in Adulthood

Honesty is a highly valued trait. It is thus not surprising that parents devote considerable efforts to promote honesty and punish lying. However, little emphasis is placed on parents being honest with their children. In fact, many parents often lie to their children for parenting purposes, known as ‘parenting by lying’. This study examines the long-term effects of parenting by lying during childhood on adults’ honesty to their parents and their socio-emotional adjustment. Results show that parenting by lying is associated with dishonesty towards parents. Moreover, mediation analyses reveal that greater parenting by lying predicts greater severity of antisocial personality problems, which is partially mediated by lying to parents. In contrast, the relation between parenting by lying and externalizing problems is fully mediated by lying to parents. This suggests that although lying may seem to be a tool for parents, its long-term impact on children’s socio-emotional development must be considered.

Keywords: development
lying
parenting by lying
socio-emotional adjustment
Advisor: Lee, Kang
Are We in this Together? Post-Separation CopParenting of Fathers With and Without a History of Domestic Violence

This paper explored features of post-separation co-parenting from men’s perspectives, in groups with and without a history of domestic violence (DV) perpetration. Thematic analysis was used to examine interviews of 20 fathers, half with a documented history of DV. The results showed substantial differences between groups. Among fathers with no history of DV, three themes were created: (1) I value my ex-partner’s involvement with our child, (2) We’re good as co- parents, and (3) How we co-parent impacts our child. Two themes were created for DV fathers: (1) My ex-partner is a bad mother and (2) She’s responsible for our difficulties co-parenting. Results indicate the need for policy and practice to reflect that the end of an abusive romantic relationship does not necessarily predict functional co-parenting or end child exposure to conflict. Furthermore, particular features may belie distressed co-parenting and could be useful to identify when assessing risk for post-separation DV.

Keywords: Child Maltreatment
Co-Parenting
Domestic Abuse
Domestic Violence
Fathers
Post-Separation
Advisor: Scott, Katreena
Familial Risk and Sibling Mentalization: Links with Preschoolers' Internalizing Problems

The current study explored whether older sibling mentalization moderated the relationship between familial risk for internalizing symptoms and the development of future internalizing problems in the younger siblings. Data were collected on 397 older siblings at Time 1 (T1) when target children were newborn and their older siblings were on average 2.61 years old (SD=.75). Target children were on average 1.60 years old at Time 2 (T2). Internalizing problems were assessed via mother and father reports. Older sibling mentalization was observed and coded during a sibling pretend-play interaction. Results revealed a significant interaction between familial risk of internalizing problems and older siblings’ mentalizing abilities. Familial risk was related to target children’s internalizing problems in the absence of sibling mentalization. Familial risk was not associated with target children’s internalizing problems when siblings demonstrated mentalizing abilities. Findings support the need to consider sibling mentalization as a protective factor for children’s internalizing problems.

Keywords: Familial Risk
Internalizing Problems
Internal state talk
Protective Factors
Siblings
Advisor: Jenkins, Jennifer
Sibling Personality Traits, Dyadic Gender Composition, and Their Association with Sibling Relationship Quality

The current study contrasted two different hypotheses about the relationship between sibling personality and sibling relationship quality: absolute value and dyadic similarity. The absolute value hypothesis suggests that the level of one siblingâ s personality will predict sibling relationship quality. The dyadic similarity hypothesis argues that it is the similarity between siblings on personality that will be associated with sibling relationship quality. Observational data on child personality and maternal-report data on sibling relationship quality were collected on 321 sibling dyads (N=642). Children were videotaped while completing five tasks and personality traits were rated by independent raters based on thin-slice methodology. Support was found for the absolute value hypothesis but not the sibling similarity hypothesis: the personality traits of younger siblings predicted sibling relationship agonism, particularly when the older sibling was female. Findings suggest that older sisters are more sensitive to negativity in their younger siblings than older brothers.

Keywords: dyadic gender
personality
relationship quality
siblings
Advisor: Jenkins, Jennifer M
Evaluating the Prevalence, Nutritional Quality, and Marketing Characteristics of Nutritionally-enhanced Foods in Canada

Nutritionally-enhanced foods are a fast-growing sector of the global food industry. Concerns have been raised that the consumption of these products may have negative repercussions on population health, such as high nutrient intakes inappropriate for certain population subgroups (e.g. children) and the shifting of dietary patterns to include more unhealthy foods. This thesis aimed to evaluate the prevalence, nutritional quality, and marketing characteristics of foods with added nutrients in the Canadian market. Many nutritionally-enhanced foods contained high levels of nutrients beyond recommended intakes, despite these nutrients having no evidence of inadequacy in the Canadian population. Additionally, a large proportion of foods with added nutrients had poor nutrient profiles and carried heavy marketing on their labels, regardless of their nutritional quality. These findings support concerns surrounding the consumption of foods with added nutrients and suggest the need to further evaluate these concerns by investigating consumer attitudes and decision-making towards these foods.

Keywords: fortified foods
functional foods
supplemented foods
Advisor: L'Abbe, Mary R
Wave Propagation Behaviour in Symmetric and Non-symmetric Three-dimensional Lattice Structures for Tailoring the Band Gaps

In this thesis, the longitudinal flexural wave propagation behaviour through symmetric and non-symmetric tetrahedral and pyramidal lattice structures is analyzed. Finite element analysis employing Floquet-Bloch theory is used to generate and plot dispersion curves. The design variables of the lattice structures are modified to analyze their impact on the dispersion curves. In symmetric lattice structures, changes in stiffness and density provide the effect of scaling the dispersion curves, whereas in non-symmetric lattice structures, based on the location of the inhomogeneities applied, asymmetric dispersion relations are obtained. For systems in which only certain directions of wave propagation are considered, non-symmetric lattice structures and the resulting asymmetric dispersion relations demonstrate great strength in terms of their flexibility when tailoring dispersion curves, as a large number of directionally different dispersion curves can be obtained, providing more options to design and optimize the lattice structure. Critically, band gaps can be designed at desirable frequencies and directions.

Keywords: 3D Lattice structure
Band gap
Dispersion relations
Periodic lattice structure
Wave propagation
Advisor: Steeves, Craig A
Investigating the Role of mrck-1 in C. elegans Excretory Cell Development

Cerebral cavernous malformations (CCMs) are neurovascular lesions that cause myriad neurological symptoms, including seizure and hemorrhagic stroke. While the key genes responsible for CCM have been identified, the molecular basis for CCM remains an intense area of research. We have employed a nematode model to investigate the CCM signalling pathway in vivo. The Caenorhabiditis elegans excretory cell is a sensitive model of biological tubulogenesis. We previously found that the conserved disease-causing gene ccm-3 drives excretory canal extension by promoting CDC-42 signalling. My work shows that a CDC-42 effector, the kinase MRCK-1, signals downstream of CCM-3 in this process. I show that the myosin light chain is a key downstream target of the CCM-3 signalling pathway. My findings offer insight into a controversial signalling pathway and provide many avenues for further investigation.

Advisor: Derry, W. Brent
The Investigation of Novel Functions of Abscisic Acid 2 Through Protein-protein Interactions

Abscisic acid (ABA) is a plant hormone that plays a regulatory role in the water stress response, maintenance of seed dormancy, and mitigation of other abiotic stresses. ABA2 is the enzyme that catalyzes the second-last step of ABA biosynthesis in the cytosol, converting xanthoxin to abscisic aldehyde. The recent discovery of ABA2 nuclear localization and its unique expression pattern may point to a previously uncharacterized function of this enzyme. In order to elucidate novel roles, we analyzed interaction partners using yeast-two hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays. Hypersensitive to ABA 1 (HAI1), a protein phosphatase 2 C (PP2C), was found to interact with ABA2, in addition to other members of this family. These proteins are part of the core ABA signaling complex and act as negative regulators of ABA-induced gene expression. Preliminary evidence suggests that ABA2 acts through HAI1, and likely other members of the PP2C family, to enhance ABA signaling.

Keywords: ABA
ABA2
HAI1
Advisor: Nambara, Eiji
Wide-range 7-switch Flying Capacitor Based DC-DC Converter for Point-of-load Applications

In this thesis a dc-dc converter referred to as the 7-switch flying capacitor (7SFC) based multi-level buck converter intended for point-of-load applications is presented. The 7SFC operates with the principle of “transformability” which allows it to run in several switching modes when paired with a digital controller. The mode is selected based on input and output conditions by estimating the highest efficiency mode. The 7SFC converter utilizes a flying capacitor, which for certain modes allows for a large reduction in switching losses, especially when the converter is operated with high-input voltages. Compared to the conventional 2-phase interleaved buck converter, the 7SFC is able to reduce the size of the output inductors and capacitor by 33%. The 7SFC discrete prototype is able to achieve efficiencies greater than 90% over the majority of the operating range.

Keywords: Buck Converter
DC-DC Converters
Point-of-Load
Power Electronics
Power Supplies
Power Systems
Advisor: Prodic, Aleksandar
The Role of Galectin-1 on B cell Activation

While intracellular regulatory mechanisms that govern B cell activation are well understood, significant gaps in our knowledge remain regarding extracellular mechanisms that may regulate B cell signalling and activation. Galectins, which are glycan-binding proteins, are known to form glycan-galectin lattices which can regulate protein-protein interactions on the cell surface. Thus, we examined a role for Galectin-1 (Gal-1) as an extracellular modulator of B cell activation. We found that Gal-1 is important in mediating isotype switching to IgG2a and IgA antibodies during antigenic challenge demonstrating a crucial role for the protein in regulating the humoral response. We show that the ligand for Gal-1 is present on the surface of naïve B cells and that B cells secrete Gal-1 upon activation. Finally, we found that recombinant Gal-1 can enhance cell-cell interaction between macrophages and B cells thus demonstrating an important role for the protein in promoting cell-cell interaction between B cells and antigen presenting cells.

Keywords: B cell activation
B cells
Galectins
Immune system
Immunology
Advisor: Treanor, Bebhinn
The Molecular Basis of Structural Plasticity of Dentritic Spines

The dynamics of actin, the major cytoskeletal component in dendritic spines, is responsible for the regulation of spine morphogenesis, formation, and elimination. Furthermore, activity-induced input-specific actin polymerization at dendritic spines have been suggested as a plausible mechanism for synaptic tagging, a process that involves the selective marking of potentiated synapses that is necessary for the proper establishment of LTP. P21-activated kinases (PAKs) are known regulators of actin dynamics and their mutations have been linked with cognitive deficits and impaired synaptic plasticity. Despite the importance of PAKs in learning and memory, their role in dendritic spines' structural plasticity remains elusive. Here, we show that group I PAKs are important for basal spine morphology, density, and maturation by using two-photon microscopy and organotypic hippocampal slice cultures. In addition, PAK1/3 DKO also exhibited impaired structural plasticity and input-specificity following glutamate-uncaging, but normal basal spine dynamics, demonstrating the importance of PAKs in activity-dependent structural modifications.

Keywords: actin
input-specificity
LTP
PAK
structural plasticity
synaptic plasticity
Advisor: Okamoto, Kenichi
Wang, Luyang
Asset Allocation using Regime Switching Methods

The aim of this thesis is to develop a Markov Regime Switching framework that can be used in asset allocation in conjunction with Modern Portfolio Theory. Modern Portfolio Theory has long been a popular tool among big financial institutions. However, one of its major limitations is assumption of stationary market volatility. In this paper, we develop a single period Mean Variance Optimization model that minimizes the variance of a portfolio subject to a specified expected return by combining Modern Portfolio Theory with a Markov Regime Switching framework. Then, we extend the above developed framework to be used in conjunction with a robust optimization framework as proposed by Goldfarb Iyengar in which regards we were partially successful. The portfolios constructed by the Markov Regime-Switching framework were tested out of sample to outperform those suggested by a Simple MVO One Factor model and the Robust MVO One Factor Model.

Advisor: Kwon, Roy H.