title: Role of Iron Chelation in Inflammation and Infection

contributor:
Department of Physiology & Biophysics
Doctor of Philosophy
Dr. Lin Zou
Dr. Alex Quinn
Dr. Zhenyu Cheng
Dr. David Hoskin
Dr. Younes Anini
Dr. Christian Lehmann
Dr. Valerie Chappe
Received
Not Applicable
Not Applicable

subject:
Inflammation
Infection
Iron
Sepsis
Iron Chelation
Cystic Fibrosis

abstract: Iron is an essential element for most forms of life, as its redox-cycling capabilities enable its participation in numerous physiological reactions. However, iron levels must be tightly regulated to avoid free iron toxicity via catalysis of reactive oxygen species (ROS), which activate pro-inflammatory pathways. Iron dysregulation and excessive ROS production (oxidative stress) have been linked to dysregulated immune response and persistent infections. Two well-known examples of pathology induced by these changes are sepsis and cystic fibrosis. At the present time, there are no specific approved treatments for immune dysregulation. Additionally, antibiotic-resistant infections are becoming more difficult to clear. Iron chelators are potentially capable of addressing both needs by restricting iron availability for ROS production and reducing bacterial growth through nutritional immunity. Thus, we sought to investigate the anti-inflammatory and anti-bacterial effects of iron chelation by using DIBI, a highly specific, synthetic iron chelator. DIBI’s efficacy in vivo was assessed in three murine models of sepsis (endotoxemia, CASP, and CASP-I) and it was compared to the FDA-approved iron chelators deferiprone, deferoxamine, and desferasirox. We found that DIBI effectively alleviated sepsis-induced leukocyte-endothelial interactions and preserved capillary perfusion in the intestinal microvasculature. Moreover, when administered in combination with an antibiotic, imipenem, DIBI reduced bacterial growth and improved survival outcome. In vitro, DIBI had a dose-specific effect on the secretion of IL-6 and IL-8 by nasal epithelial cells with cystic fibrosis disease-causing mutations. The lower studied dose of DIBI (25 μM) had a pro-inflammatory effect, whereas the higher dose (200 μM) had an anti-inflammatory effect. Overall, these findings suggest a promising role for the therapeutic application of DIBI, as a novel approach for attenuating the dysregulated inflammatory response and potential adjuvant in anti-bacterial therapy.


title: Equity in Health Care Utilization Among First Nations Populations Living Off-reserve in Canada

contributor: Department of Community Health & Epidemiology

subject:
Health care utilization
Indigenous
Equity

abstract:
Background: Reducing inequities (unfair inequalities) in health and health care is a primary goal of health policy in Canada. Inequity in utilization of care is a significant issue. Inequity may be present in the utilization of many types of health care services including but not limited to: primary care, specialist care, mental health care and dental care. Although the investigation of inequity in health care utilization is common in the general population and several subpopulations in Canada, little research has been done to assess inequities in health care utilization within Indigenous populations in this country. There are several reasons to investigate inequity in health care utilization among this population, including differences in health status, health care coverage and cultural/historical context.
Objective: To examine income-related inequity in four types of health care utilization within two off-reserve Indigenous populations in Canada viz. status and non-status First Nations, namely: primary care (general practitioner/nurse care), specialist care, dental care and mental health care utilization.
Methods: The study was conducted as a secondary analysis using a cross-sectional survey. We used the 2012 Aboriginal Peoples Survey (APS), which is a nationally representative survey of the off-reserve Indigenous populations in Canada administered through statistics Canada. The survey collects information on income, health care utilization, need and various other non-need variables required for the analysis. The target population for this research was adults (>18 years) who self-identified as a member of any First Nations group in Canada. Inequity was assessed using multiple methods: the Horizontal Inequity index (HI) was calculated for primary and specialist care to compare the degree of horizontal inequity between both status and non-status First Nations groups. The Concentration index (C) and logistic regression was employed for testing inequity in both mental and dental health care utilization for these populations.
Results: This research indicated significant inequities in health care utilization within First Nations peoples living off-reserve in Canada. Specifically, there is pro-rich inequity in primary care utilization for the total First Nations populations, HI: 0.2085 (95% CI: 0.1521, 0.2649) and for those in each status group individually (more pro-rich in the status population). Additionally, inequity in dental care utilization is present based on the concentration index of actual use for those who need care. We find pro-rich inequity in the total population, C: 0.0812 (95% CI: 0.0182, 0.1442) and in the non-status population, C: 0.1783 (95% CI: 0.0771, 0.2794). Results also show no evidence of inequity in specialist care utilization or mental health care utilization, although statistically insignificant point estimates for inequity are moderately pro-rich.
Conclusion: This research has filled a gap in the literature around inequity in health care utilization for off-reserve First Nations populations in Canada by measuring inequity within both status and non-status groups individually. These results have provided insight into income-related inequities in health care utilization for First Nations populations in Canada and may provide valuable evidence for policy makers in this area.


title: Some Aspects of the Inorganic and Organometallic Chemistry of Dipyrrins

contributor:
Department of Chemistry
Master of Science
Zhang, Peng
Speed, Alex
Schepp, Norm
Thompson, Alison
Not Applicable
Not Applicable
Not Applicable

subject:
Dipyrrins
BODIPYs
Coordination chemistry
Main Group
Synthesis

abstract:
Oligopyrroles and their complexes with metals and metalloids are often intensely coloured, and as such, are well-studied as dyes and components of organic light-harvesting systems. Of particular interest in this thesis are (aza-)dipyrrins, conjugated dipyrrolic frameworks that act as convenient and highly tunable LX-type bidentate ligands. Boron complexes of (aza-) dipyrrins, called BODIPYs, are extremely well-studied as robust and flexible fluorescent dyes. Dipyrrinato complexes of other metals have also been studied for a plethora of applications from photomedicine and photovoltaics to catalysis and chemical sensors.
In Chapter 2, the electron-donating capability of thirteen (aza-)dipyrrinato ligands are evaluated for the first time using 13C NMR spectroscopy and a probe based on an air-stable Pd-NHC complex, which is one of the few systems appropriate for the measurement of LX-type bidentate systems such as these. The measured donor strengths are rationalized based on chemical structure, and compared to other common ligands for which donor strength has been measured via this system.
In Chapter 3, the design of an improved synthetic route toward aza-dipyrrins is detailed. Aza-dipyrrins and their complexes have significant potential as long-wavelength chromophores, but currently available synthetic routes severely limit the range of substitution patterns that can be accessed. An improved synthesis is described where the aza-dipyrrin core is built from acyclic precursors, avoiding the generation of unstable intermediates that render traditional methods inflexible. Preliminary experimentation with the aim of validating this method is also included, and considerations for future development are discussed.
Chapter 4 describes the serendipitous discovery of a previously unreported class of azobispyrrole during the attempted synthesis of aza-dipyrrins with enhanced fluorescence. These azobispyrroles were found to exhibit unusual behaviour, lacking observable photoisomerization but instead displaying strong solid-state fluorescence.
Finally, Chapter 5 details the design and synthesis of BODIPYs bearing 2-tellurophenyl substituents. The inclusion of the tellurophene moiety affords substantial bathochromic shifts in the optical profiles of these BODIPYs. BODIPYs bearing this substituent at the alpha-position(s) have potential as bifunctional probes for mass and fluorescence cytometry, and those bearing the substituent at the beta-position(s) may be used as photosensitizers for photodynamic therapy. This work contains the first examples of BODIPYs bearing tellurophene moieties.


title: Design, Synthesis, and Evaluation of Thymidine Derivatives as Inhibitors of a Thymidylyltransferase Enzyme, Cps2L

contributor:
Department of Chemistry
Master of Science
Peng Zhang
Alex Speed
Stephen Bearne
David Jakeman
Not Applicable
Not Applicable
Not Applicable

subject:
Enzyme
Synthesis
Inhibition
Drug design
Iminoboronate

abstract: The inhibition of thymidylyltransferase enzymes has long been studied as a potential avenue for antibiotic development. Several thymidine derivatives were designed, synthesized, and evaluated for binding and inhibition against Cps2L, a thymidylyltransferase enzyme present in the bacteria Streptococcus pneumoniae. Compounds that were evaluated via WaterLOGSY binding studies indicated binding. Furthermore, most compounds demonstrated reversible inhibition, with many of those displaying Ki values within micromolar ranges. Compounds 4d and 4e bearing aldehydes, and compounds 4a and 4b bearing ortho-formylarylboronic acid pinacol esters, have the potential to covalently modify lysine residues at the active site of Cps2L. Particular potency was observed from compounds 4d and 4f; structure-activity relationship studies with these compounds may provide future directions for the iterative design of these inhibitors.


title: Developing a new spatio-temporal framework for assessment of the Nova Scotia Inshore Sea Scallop (Placopecten magellanicus) Fishery

contributor:
Department of Biology
Master of Science
Sophia Stone
David Keith
Jessica Sameoto
Aaron MacNeil
Joanna Mills Flemming
Jeffrey Hutchings
Not Applicable
Not Applicable
Not Applicable

subject:
stock assessment
fisheries
spatial
random fields
delay-difference model
scallops

abstract:
The Nova Scotia Inshore Sea Scallop (Placopecten Magellanicus) Fishery is the fourth most valuable fishery in the province and has been in existence since the 1960s. Covering the Bay of Fundy and areas close to the shore of Nova Scotia, it is split up into multiple Scallop Production Areas (SPA) and Scallop Fishing Areas (SFA). Most areas are assessed separately with a different yearly Total Allowable Catch (TAC) set to limit maximum landings. SPA 3, encompassing St-Mary’s Bay and a good portion of the western shore of Nova Scotia, has been difficult to assess due to its strong spatial patterns in both biological characteristics and fishing effort.

The current model typically used to assess areas of this fishery is a delay-difference model, a type of biomass dynamics model which only requires an index of abundance and commercial landings. However, even after recasting it into a frequentist framework, this model has been found to be unable to reliably model SPA 3. The focus of this work is to incorporate spatial information into this assessment model in two steps. The first step involves reconsidering abundance indices to reduce the amount of necessary pre-processing and directly model all intra-annual variability, while simultaneously accounting for the large number of zeroes. The second step involves explicitly modeling the location of survey tows and commercial fishing by modifying the error structure of the model by using Gaussian Markov Random Fields such that a spatio-temporal model results.

The new framework for abundance indices is shown to better capture population changes and can be viewed as a hybrid between a traditional temporal model and a spatio-temporal version. The full spatio-temporal stock assessment framework is further able to capture both local population changes reliably and population trends for the entire area of interest. This novel framework shows promise to improve the reliability of scientific advice given to fisheries managers while opening up new possibilities for spatial management.

abstract:
The current stock assessment model model used to assess areas of the Nova Scotia Inshore Sea Scallop (Placopecten Magellanicus) Fishery is a delay-difference model. However, this model has been found to be unable to reliably model the Scallop Production Area 3. The focus of this work is to incorporate spatial information into this assessment model in two steps. The first step involves reconsidering abundance indices to reduce the amount of necessary pre-processing and directly model all intra-annual variability, while simultaneously accounting for the large number of zeroes. The second step involves explicitly modeling the location of survey tows and commercial fishing by modifying the error structure of the model by using Gaussian Markov Random Fields such that a spatio-temporal model results.

The new framework for abundance indices is shown to better capture population changes and can be viewed as a hybrid between a traditional temporal model and a spatio-temporal version. The full spatio-temporal stock assessment framework is further able to capture both local population changes reliably and population trends for the entire area of interest. This novel framework shows promise to improve the reliability of scientific advice given to fisheries managers while opening up new possibilities for spatial management.


title: Patient-Specific Collision Zones for 4π Trajectory Optimized Radiation Therapy

contributor: Department of Physics & Atmospheric Science

subject:
Medical Physics
Stereotactic Body Radiation Therapy

abstract: This thesis presents a system that determined patient-specific collision zones (CZs) to enable safe and deliverable non-coplanar treatment trajectories for stereotactic body radiation therapy (SBRT) patients. Full body scans of patients in treatment position were acquired using an optical scanner, creating a library of scans to augment CT scans. This resulted in a patient model that was aligned with a model of the treatment LINAC, where both components were rotated to test for collisions. To test collision detection accuracy an end-to-end cranial test was performed. The buffer sized required during the registration process to achieve a sensitivity of one was determined via a registration accuracy test. Incorporating the patient-specific CZs, non-coplanar treatment plans were created and compared to clinical coplanar plans for SBRT lung patients (N = 8). A statistically significant change in the mean dose to the lungs was found. Our study indicated that determining patient-specific CZs can be accomplished enabling safe non-coplanar treatment plans.


title: Maternal and Neonatal Outcomes in Twin Pregnancies Complicated With Gestational Diabetes Mellitus Compared to Twin Pregnancies Without Gestational Diabetes Mellitus: A Population-based Retrospective Cohort Study of Nova Scotia Births

subject:
gestational diabetes mellitus
twin pregnancy

abstract:
Background: Gestational diabetes mellitus (GDM) is broadly defined as diabetes that is first diagnosed during pregnancy. It can lead to complications in singleton pregnancies for both mother and baby, such as excessively high birthweight and consequentially the need for Caesarean section, shoulder dystocia, birth trauma, gestational hypertension, and neonatal hypoglycemia. Women carrying twins have increased risk of adverse maternal and fetal outcomes such as growth restriction, discordant growth, pre-eclampsia and preterm delivery, but few studies have examined the outcomes of GDM among twin pregnancies.
Objectives: This study investigated twin pregnancies, comparing women affected by GDM to those unaffected with respect to: (1) maternal outcomes including hypertensive disorders of pregnancy, placental abruption, preterm delivery, mode of delivery and antepartum length of stay and (2) neonatal outcomes of perinatal death, hypoglycemia, birthweight discordance, small for gestational age (SGA), large for gestational age (LGA), neonatal intensive care unit (NICU) admission, neonatal length of stay, respiratory distress and low Apgar score.
Methods: The retrospective cohort study was carried out using provincial data from the Nova Scotia Atlee Perinatal Database (NSAPD) between 1988 and 2013. Adjusted odds ratios (aOR) with 95% confidence intervals (CI) for the association between GDM and each outcome were estimated from logistic regression models with generalized estimating equations to account for nonindependence between twins.
Results: 2374 women who delivered twins were included, 109 (4.6%) of whom had GDM. Outcomes with estimated aORs > 1.30 included hypertensive disorders of pregnancy (aOR 1.44, 95% CI 0.88-2.38), an antepartum length of stay > 48 hours (aOR 1.55, 95% CI 0.97-2.50) and Caesarean section (aOR 1.34, 95% CI 0.87-2.07). Neonates born to mothers with GDM had estimated aORs > 1.30 for the outcomes of hypoglycemia (aOR 3.07, 95% CI 1.82-5.19) and small for gestational age (aOR 1.46, 95% CI 0.99-2.15), while aORs < 0.77 were calculated for respiratory distress (aOR 0.70, 95% CI 0.41-1.22), and low Apgar score (aOR 0.53, 95% CI 0.23-1.23).
Conclusions: The results of this study confirmed some associations previously noted in the literature while finding differing results of other associations. The study suggested an association between GDM and a longer antepartum length of stay in women pregnant with twins, an outcome not previously examined. Further research is warranted, ideally with larger study numbers and information on maternal glucose control during pregnancy.


title: The Prison Landscape: Redefining Built Form to Support Rehabilitation

contributor:
School of Architecture
Master of Architecture
Chris Trumble
Steve Parcell
Adelina Iftene
Steve Parcell
Not Applicable
Not Applicable
Not Applicable

subject:
Correctional Services Canada
Collective Living
Architecture
Prison
Rehabilitation
Security
Cowansville, Quebec

abstract:
Correctional institutions of Correctional Services Canada have been developed to maximize efficiency in security, control, circulation, cost, and use of resources. Often this utilitarian and functionalist approach fails to consider the human experience side of this landscape, and has negative effects on the primary goals of these facilities: rehabilitation.
Rehabilitation provides a platform for offenders to rebuild essential life skills and self-sufficiency to successfully reintegrate with society. With declining crime rates, increasing prison populations and high recidivism rates, it suggests that the current model is an easy, but not effective response to crime.
Through analyzing Cowansville Institution, a medium-security federal facility near Montreal, Canada, this thesis aims to develop a set of design guidelines for updating the existing prison landscape to better meet the goals of rehabilitation through methods of normative design and encouraging relationships within and beyond the walls, while maintaining user safety.


title: ASSESSING THE ULTRAVIOLET OPTICAL SCREENING TOOL FOR DELINEATING AN IN-SITU, WATER-COVERED, CONTAMINATED SEDIMENT LAYER

contributor:
Department of Environmental Engineering
Master of Applied Science
Dr. Barret Kurylyk
Dr. Tony Walker
Dr. Rob Jamieson
Dr. Craig Lake
Dr. Ian Spooner
Not Applicable
Not Applicable
Not Applicable

subject:
Environmental Remediation
In-situ sampling
Delineation
Contamination
Sediment
UVOST

abstract:
A stabilization lagoon in Pictou County, NS, has been receiving industrial wastewater for the past 50+ years and is slated for remediation. Conventional sampling has identified a layer of black effluent influenced sediment contaminated with dioxins and furans overlying an uncontaminated grey estuarine influenced sediment. In this thesis, laboratory and field testing on the sediments are presented as a proof of concept for a unique application of the Ultraviolet Optical Screening Tool (UVOST).
This research presents an alternative use for the UVOST; the ability to delineate the spatial distribution of an organic-rich, unconsolidated, water-covered sediment, contaminated with dioxins, furans, and elevated metals. The results of this study indicate that the UVOST can be utilized at freshwater aquatic sites to delineate an organic-rich sediment which overlays a clastic sediment layer. The resolution of the acquired data was shown to provide multiple surface elevations (i.e. water and sediment layers) simultaneously.


title: EVALUATING INHIBITION OF DNA METHYLATION AND ALDH1A3 AS BREAST CANCER THERAPIES

contributor:
Department of Pathology
Doctor of Philosophy
Franco Vizeacoumar
Wenda Greer
Roy Duncan
David Hoskin
Ian Weaver
Paola Marcato
Carman Giacomantonio
Received
Not Applicable
Yes

subject:
DNA methylation
Decitabine
Breast Cancer
Cancer Stem Cells
ALDH1A3

abstract:
Breast cancer is the most common form of cancer among Canadian women. Patients with triple-negative breast cancer (TNBC) have poor prognoses, with inherently more aggressive disease and limited treatment options. New modalities for treating TNBC are required. Here, I investigate a precision medicine approach to applying DNA hypomethylating therapy and assess the potential benefits of targeting breast cancer stem cell (CSC) marker aldehyde dehydrogenase 1A3 (ALDH1A3).
Dysregulation of DNA methylation is an established feature of breast cancers. DNA hypomethylating therapies like decitabine are proposed for the treatment of TNBC yet indicators of response need to be identified. I demonstrate the requirement of deoxycytidine kinase (DCK) for decitabine response in breast cancer cells; however, no predictive features or other mediators of decitabine response were identified. An shRNA-based genome-wide screen was performed to detect potent hypermethylated genes or novel mediators of decitabine. I found that loss of methylene tetrahydrofolate dehydrogenase 2 (MTHFD2) conferred decitabine resistance to TNBC cells likely by suppressing cell proliferation via limiting nucleotide biosynthesis. Therefore, while hypermethylated genes that predict hypomethylating therapy response were not obtained, the relevance of emerging drug target MTHFD2 to TNBC was confirmed.
CSCs are a highly aggressive subpopulation of cells within breast tumours and are identified by their high ALDH1A3 activity. In addition to its role as an established CSC marker, ALDH1A3 plays a key role in the progression and metastasis of breast cancer. Therefore, ALDH1A3 represents a druggable anti-cancer target of interest. Nanoparticle encapsulation of ALDH1A3 inhibitor citral reduced ALDH1A3-mediated growth of MDA-MB-231 TNBC tumours. Metabolomic and gene expression analyses identified γ-aminobutyric acid (GABA) signaling/metabolism as a dysregulated pathway in ALDH1A3-hi breast tumours. In mice treated with systemic GABA there was higher rates of lung metastasis. Patient dataset analyses revealed that metastatic breast cancer has a distinct GABA metabolism profile.
Together, these results suggest two new approaches for TNBC therapy: 1) use MTHFD2 to stratify patients for hypomethylating therapy or directly inhibit MTHFD2 and 2) inhibit ALDH1A3 to potentially control GABA-mediated metastasis.


title: Adapting drinking water treatment strategies to changing source water quality under the stress of climate impacts

contributor:
Department of Environmental Engineering
Master of Applied Science
Dr. Barret Kurylyk
Dr. Margaret Walsh
Dr. Azadeh Kermanshahi-pour
Dr. Graham Gagnon
Dr. Amina Stoddart
Not Applicable
Not Applicable
Not Applicable

subject:
coagulation
natural organic matter
drinking water treatment
lake recovery from acidification

abstract: Over the last few decades, noticeable chemical and microbiological changes in water quality have been observed in Atlantic Canada lakes as a result of recovery from acidification and climatic drivers. This has multiple implications for drinking water treatment in unconventional plants (i.e. without sedimentation or flotation), in both the quality and quantity of drinking water produced, causing increased concentrations of disinfection by-products, the potential for algal toxins in drinking water, and plugging of unit processes. Two drinking water utilities that were built prior to the observed changes in source water quality are experiencing or anticipating the aforementioned consequences and immediate solutions are needed to mitigate the problem while more long-term sustainable designs are implemented. The objective of the presented research was to investigate both immediate strategies and potential longer-term solutions to adapt to long-term changes and seasonal fluctuations in lake water quality.


title: Damaged Perspectives: Towards a Visual Reading of Donald Barthelme's Picture Stories

contributor:
Department of English
Master of Arts
Dr. Kathleen Cawsey
Dr. David Evans
Dr. Julia M. Wright
Dr. Anthony Enns
Not Applicable
Not Applicable
Not Applicable

subject:
Barthelme, Donald
Collage
Visual Arts
Short Stories
Postmodernism
Modernist Art

abstract: America’s literary scene in the 1960s and 70s was a site of formal experimentation. Authors became discontented with the rational linearity of the written text and began to look for ways to disrupt it. Donald Bathelme is one of many authors of this time to incorporate images into his works, particularly during the composition of City Life (1970), Sadness (1972), and Guilty Pleasures (1974). My thesis focuses on three stories— “Brain Damage,” “At the Tolstoy Museum,” and “The Flight of the Pigeons from the Palace”—from this period of Barthleme’s work that incorporate images. I argue that these stories constitute visual-textual collages that operate under the same principles as those undertaken by modernist visual artists, and that they should be interpreted using the same framework. Moreover, an analysis of Barthelme’s visual semiotics demonstrates that these stories share the epistemological and aesthetic concerns of the modernist movement in the visual arts.


title: “DARKE HIDDEN VERTUOUS”:  DECONSTRUCTING THE VIRGIN FIGURE IN MARY WROTH’S LOVE’S VICTORY  AND JOHN FLETCHER’S THE FAITHFUL SHEPHERDESS

contributor:
Department of English
Master of Arts
Cawsey, Kathleen
Barker, Roberta
Brown, Andrew
Luckyj, Christina
Not Applicable
Not Applicable
Not Applicable

subject:
Early Modern Literature
Gender and Sexuality
Virginity

abstract: This project analyzes the virgin figure as deployed by two Protestant playwrights. Clorin in John Fletcher’s The Faithful Shepherdess (c.1608) and Silvesta in Mary Wroth’s Love’s Victory (c.1620) are anomalous characters, remaining firm in their celibacy past the close of their respective plays. My research considers the use of these virgin figures in connection to early modern constructions of gender and sexuality, analyzing the virgin’s significance for theatrical performance, Petrarchan poetics, and female religio-political action. While Wroth uses Silvesta to challenge limitations on the virgin body’s potential, Fletcher ultimately reinforces a patriarchal sex/gender model, although both plays demonstrate the utility of the virgin figure as a discursive tool.


title: X-ray Spectroscopy Studies of Ligand-protected and Zeolite-confined Silver Nanoclusters

contributor:
Department of Chemistry
Master of Science
Dr. Peng Zhang
Dr. Saurabh Chitnis
Dr. Erin Johnson
Dr. Peng Zhang
Not Applicable
Not Applicable
Yes

subject: X-ray Absorption Spectroscopy

abstract: Ultrasmall silver nanoparticles, also known as silver nanoclusters (Ag NCs), are of interest because of their ultrahigh surface-to-volume ratio and strong quantum size effect. In this work, the studies of Ag NCs with ligand protection and zeolite confinement are presented. X-ray spectroscopy techniques were employed as major tools to characterize the structure and electronic properties of these protected Ag NCs. The site-specific analysis of ligand-protected Ag25 NCs gives an in-depth understanding of the electronic and bonding properties of each site in the NCs, which offers a detailed picture on the structure-property relationship of the NCs. The study of zeolite-confined Ag NCs suggests their structure and electronic properties can be tuned by controlling the concentration of silver ions and types of zeolites. A preliminary catalytic study showed that these NCs prepared in this work exhibit promising catalytic activity, and implied that they could be promising materials for catalytic applications.


title: HAPTOGLOBIN PHENOTYPE, HDL-CHOLESTEROL RAISING THERAPY (FIBRATE), AND RISK OF CARDIOVASCULAR DISEASE EVENTS WITHIN THE ACTION TO CONTROL CARDIOVASCULAR RISK IN DIABETES (ACCORD) LIPID TRIAL

subject:
coronary heart disease
epidemiology
genetic association
glycoproteins
type 2 diabetes mellitus

abstract:
Background: The failure of many clinical trials aimed at preventing cardiovascular disease (CVD) by pharmacologically raising high-density lipoprotein (HDL) cholesterol has cast doubt on the idea that more HDL-cholesterol is better and that the function of HDL may be of more importance. The haptoglobin (Hp)2-2 phenotype (~40% of people) is associated with dysfunctional HDL that can become heavily oxidized in hyperglycemia. The effect of raising potentially pro-atherogenic HDL-cholesterol on risk of CVD in the Hp2-2 phenotype in hyperglycemia is unknown.

Objectives: 1) To determine whether the effect of adding fenofibrate therapy to simvastatin therapy on risk of coronary heart disease (CHD) and CVD events depends on Hp phenotype, and 2) to determine whether the association between HDL-cholesterol and cardiovascular events (CHD and CVD) depend on Hp phenotype, in type 2 diabetes mellitus (T2DM). These objectives were also examined in men and women and in primary and secondary prevention patients separately.

Methods: Haptoglobin phenotype was determined using a validated assay in 4,996 men and women with T2DM who participated in the ACCORD lipid trial with a mean follow-up of 4.7 years for CVD and 4.6 for CHD. In an intention-to-treat analysis (objective 1), multivariable Cox proportional hazards regression was used to determine the effect of fenofibrate therapy on CHD and CVD events for the two Hp phenotype groups separately. In a biomarker analysis with repeated measures over time (objective 2), multivariable Cox proportional hazards regression was used to determine the association between a 1-mg/dL increase in HDL-cholesterol and CHD and CVD events, stratifying by Hp phenotype.

Results: Fenofibrate with background simvastatin, compared to simvastatin alone, reduced the risk of CHD in Hp1 allele carriers but not in the Hp2-2 phenotype (p-value for interaction=0.009). The effects also differed by sex with a reduced risk of CHD in men who were Hp1 allele carriers and an increased risk of CHD in women with the Hp2-2 phenotype. There was a significant, inverse association between HDL-cholesterol and cardiovascular outcomes in Hp1 allele carriers but there was no significant association between HDL-cholesterol and cardiovascular outcomes in patients with the Hp2-2 phenotype, although the interaction was not significant.

Conclusion: The effect of adding fenofibrate to simvastatin on CHD and CVD risk may depend on Hp phenotype and sex. Further research is needed to understand both the relationship between fenofibrate therapy and cardiovascular events, and between HDL function and cardiovascular events in different Hp phenotypes.


title: Controlling Biofilm Formation Through Corrosion Control Agents and Coatings

contributor:
Department of Environmental Engineering
Master of Applied Science
Dr. Kevin Plucknett
Dr. Barret Kurylyk
Dr. Jennie Rand
Dr. Graham Gagnon
Not Applicable
Not Applicable
Not Applicable

subject:
Biofilms
Graphene
Antifouling Coatings
Sodium Silicates
Orthophosphates

abstract: This work explored two primary strategies for controlling biofilm. One method involved the use of sodium silicate as a corrosion inhibitor in a pilot-scale model drinking water distribution system using cast-iron mains. The second method pertained to the use of graphene-enhanced biocidal and foul release (FR) coatings to mitigate biofouling. Biofilm accumulation was evaluated utilizing biological annular reactors (ARs) and microbiological characterization techniques, such as adenosine triphosphate (ATP), heterotrophic plate counts (HPC), protein and carbohydrate concentrations in extracellular polymeric substance (EPS), as well as 16s rRNA sequencing and species identification for bacteria. Biofilm ATP concentrations from the sodium silicate-treated system were lower than the commonly used orthophosphate-treated system. In addition, graphene-enhanced coatings demonstrated the potential to reduce biomass accumulation, however biofilm ATP concentrations did not appear to be affected by an increase in shear stresses from 0.15 to 1.76 N m-2 on the FR coatings.


title: FINITE ELEMENT AND RELIABILITY STUDY OF IN-PLANE BEHAVIOUR OF CONCRETE MASONRY INFILLED RC FRAMES

contributor:
Department of Civil Engineering
Doctor of Philosophy
Dr. Tony Yang
Dr. Barret Kurylyk
Dr. Pedram Sadeghian
Dr. Gordon A. Fenton
Dr. Yi Liu
Not Applicable
No
Not Applicable

subject: Concrete masonry infilled RC frames

abstract:
This research provides a finite element and reliability study of the in-plane behaviour of masonry infilled reinforced concrete frames. In the first phase of the research, a reliability analysis was conducted to advance the understanding of the effect of the randomness and uncertainty of masonry materials on the lateral resistance of masonry infill walls from a probabilistic approach. A computationally efficient and robust finite element model was developed in OpenSees and validated using the experimental results obtained in the same research group. Coupled with the Monte-Carlo simulation techniques, the model was used to estimate the failure probability of infilled frames with a spatially varying random field of masonry compressive strength. After 1000 simulations, the resulted failure probability distribution of the infilled frames led to a new recommendation on the masonry resistance reduction factor. Despite the efficiency of the OpenSees model, running simulations of the random fields on the infilled frames on an advanced work station, with 40 Central Processing Units (CPUs) and 128 GBs of memory, took three months to complete. It became evident that a better-performing computing technology was needed for any meaningful reliability analysis of this magnitude. This motivated the second phase of the research.
In the second phase, an open-source and modular finite element library for estimating the behaviour of infilled frames was developed. The main feature of the library was to be able to significantly accelerate the numerical simulations for structural applications in general and with a focus on masonry infilled RC frames. The specific algorithms, encoded in C++, were developed for the library to be able to run on either central processing units or graphical processing units (GPUs). The library adopted an advanced smeared crack modelling technique, the Distressed Stress Field Method (DSFM), for modelling of the masonry infilled RC frames. A comparison with the experimental results showed that the DSFM was successfully incorporated in the analysis of masonry infilled RC frames. The performance of the developed library in accelerating the model run speed was demonstrated through comparisons of run speed using a CPU and several commercially available GPUs. It was shown that GPU devices with adequate memory space can lead to significant model run speedup compared with a CPU. The degree of speed-up was highly dependent on the number of elements used in the finite element model and the number of processing core available in the parallel architecture. The greater the number of elements used in the model, the greater rate of acceleration will be achieved.


title: Poly Plotlines: Narratives of Ethical Non-Monogamy in Nova Scotia

contributor: Department of Sociology & Social Anthropology

subject:
Polyamory
Ethical Non-Monogamy
Sociology of Love and Intimacy
Anthropology of Kinship
Sociology of Sexual Deviance
Kink
Realtionships

abstract: Much of the literature on polyamory is situated in the field of family studies, psychology and gender studies. These studies typically focus on describing the individual experiences of polyamorous relationships without broadly situating the practice in broader social and cultural contexts. This thesis instead, examines polyamory through the sociology of love and intimacy, the anthropology of kinship and the sociology of sexual deviance. It contextualizes why more people are exploring polyamory and other forms of consensual non-monogamies (CNMs). Drawing on interviews with polyamorous folks designed to illicit their biographical ‘sexual’ stories, I shed light on how poly folks create and give meaning to their relationship practice, particularly through their early explorations of polyamory. It explores how poly folks’ relationship(s) function within the limitations of monogamous institutions and values. Additionally, it explores the tensions that arise within the polyamorous community as the practice becomes more mainstream in North American society.


title: Service System Design Problems Under Demand Uncertainty

contributor:
Department of Industrial Engineering
Master of Applied Science
Dr. Ahmed Saif
Dr. Claver Diallo
Dr. Alexander Engau
Dr. Ahmed Saif
Not Applicable
Not Applicable
Not Applicable

abstract: The service system design problem aims to select the location and capacity of service facilities and customers’ assignments to minimize the setup, access, and waiting time costs. This thesis addresses the case when there is uncertainty about the demand for service, considering two service systems that can be modelled as independent networks of M/M/1 and G/M/1 queues. Robust optimization is used when the demand rate is unknown. However, the arrival pattern can still be reasonably approximated as a Poisson process or follow a General distribution, respectively. We use distributionally-robust optimization to address the case when the demand distribution is estimated from a limited sample. For both models, we reformulate both problems as mixed-integer second-order conic programs. For the M/M/1 model, these problems can be solved directly on commercial solvers. On the other hand, for the G/M/1 model, we use a Lagrangian-Relaxation approach to solve the problems.


title: A Walk in the Park Airport Inhabitation: Making Place in the Place-less

contributor:
School of Architecture
Master of Architecture
Chris Trumble
Steve Parcell
Marc Augé
Christian Norberg-Schulz
Edward Relph
Niall Savage
Not Applicable
Not Applicable
Not Applicable

subject:
Airport
Non-place
Terminal design
Garden design
Function system

abstract:
Airports are nodes of convergence, intersection and divergence. They are processing machines functioning solely to move people from one stage to another in an efficient, expedient manner. This thesis takes the position that the contemporary airport can be a human place that is culturally specific and functional.
The thesis first studies the airport as a system and a non-place. It then analyses the “Room” and system of historical transportation hubs and contemporary airports for clues of place-making. Finally, the thesis discovers the idea of “The Garden” as the method of growing a sense of place. The site for testing the thesis principles is Hong Kong airport. Natural and cultural design elements specific to Hong Kong are integrated into the existing airport terminal, and used to create physical/typological spaces that are human scale and engage the senses. The circulation in the terminals becomes the garden path, and the airport becomes a more connected part of the journey and an extension of the city. Moving through the airport is now – a ‘walk in the park’.


title: Colonial Sentiments: Examining Canadian Depictions of Indigenous Suicide

subject:
Suicide
Indigenous Studies
Anthropology
Content Analysis

abstract: Colonialism has long impacted the health of Indigenous peoples in Canada and has had an unquestionable relationship with Indigenous suicide rates. In this thesis I hypothesized that contrary to popular conceptions, forms of colonialism still exist today in Canadian society, perhaps providing barriers to achieving maximally effective suicide prevention and support for Indigenous peoples. I used content analysis to examine existing depictions, common themes, and models of understanding of Indigenous suicide across private media and state-created Indigenous suicide prevention policies in Canada. Both private media and suicide prevention policy were found to be mainly focused on promoting a western, biomedical conception of wellness and mental health, thus forcing Indigenous peoples to conform to one homogeneous way of healing and understanding suicide. I argue that this lack of conceptual malleability is incongruent with the particularity that the phenomenon of suicide demands.


title: COMPOSITIONAL AND FUNDAMENTAL CHARACTERIZATION OF LI-ION CELL ELECTROLYTES

contributor:
Department of Chemistry
Master of Science
Dr. Peng Zhang
Dr. Alex Speed
Dr. Mita Dasog
Dr. Jeff Dahn
Not Applicable
Not Applicable
Yes

subject:
Li-ion batteries
Electrolyte

abstract:
The electrolyte is crucial to successful lithium ion cell operation.  The composition, including the solvents and additives used will dictate how long the cell lasts. There are only a few studies that study the electrolytes from cells that have gone through a prolonged cycling sequence, even fewer that do this while focusing on specific additive combinations. This work studies a matrix of Li-ion cells with additives vinylene carbonate and ethylene sulfate to determine which additive combination is optimal for long cell lifetimes. The results are determined through a novel electrolyte extraction technique that uses NMR and GC-MS to quantify known electrolyte components and identify unknowns.
The extraction method and NMR/GC-MS method are presented in this work along with the results from the tested cells. Cells with 1 or 2% VC and 1% DTD had the most stable cycling performance but a surprising amount of electrolyte salt consumption. μ-XRF transition metal analysis of the negative electrodes are also presented. The possible degradation mechanisms of electrolytes were described but the cells tested were absent of any such products. Many additional projects using the NMR/GC-MS method described are proposed as future work.
 Lastly, NMR was used to additionally determine some transport properties of Li-ion cell electrolytes. Results found salts in methyl acetate to have faster diffusion rates compared to a DMC solution.


title: An Analysis of Salmonella from Molecular, Cellular, and Food Safety Perspectives

contributor:
Department of Microbiology & Immunology
Doctor of Philosophy
Dr. John Brumell
Dr. Zhenyu Cheng
Dr. David Hoskin
Dr. Craig McCormick
Dr. Jason LeBlanc
Dr. John Rohde
Not Applicable
Yes
Yes

subject:
Salmonella
Food Recall
Protozoa
Ubiquitin Ligase

abstract: Salmonella is a major foodborne pathogen in both developing and developed countries and is responsible for a range of diseases including enteric fever, gastroenteritis, and bacteremia. Despite advancements in food safety strategies, Salmonella illness continues to substantially contribute to foodborne related hospitalization and deaths in both Canada and the United States. While a majority of these illnesses are associated with the mishandling of raw meat, a large portion are related to outbreaks from incidental contamination of food products. In Canada, these contaminated products are recalled from retailers by the Canadian Food Inspection Agency to prevent the transmission of Salmonella. However, not all Salmonella contribute to severe health outcomes as there is a large degree of genetic heterogeneity among the 2600 serovars within the genus. This range in genetic variability across Salmonella serovars is linked to numerous genetic elements that dictate virulence. How these elements collectively constitute Salmonella disease is not completely understood. Several genetic elements encode highly studied virulence factors, such as Salmonella pathogenicity island 1 and 2, with well documented contributions to pathogenesis. However, many genetic elements implicated in Salmonella virulence remain uncharacterized. Identifying how these potential virulence factors contribute to Salmonella disease is essential to understanding the virulence disparity between serovars. In this thesis I analyze Salmonella from molecular, cellular, and food safety perspectives to investigate some of these research questions. First, I examine the contributions of Salmonella to microbial-related recalls in Canada from 2000-2017 in which I highlight recent increases in Salmonella-related recalls involving fruits, vegetables, and leafy greens. Second, I discuss my research on evaluating protozoa as a screening model for Salmonella virulence and present the Acanthamoeba screening model I developed to characterize the virulence of clinical and environment isolates of Salmonella. Third, I explore the role of the E3 ubiquitin ligase effector SspH1 during Salmonella infection and demonstrate that it stimulates degradation of the host kinase PKN1. In addition, I investigate the prevalence of sspH1 in a large collection of Salmonella isolates (the Syst-OMICS consortium) and reveal a potentially new SspH1-related protein. Lastly, I propose future directions related to the work presented in my thesis.


title: A Biomechanical and Neuromuscular Investigation of Femoroacetabular Impingement: Understanding Pathomechanics using Inclined and Declined Walking

contributor: School of Physiotherapy (Rehabilitation Research)

subject:
Biomechanics
Femoroacetabular Impingement
Kinematics
Electromyography

abstract: Femoroacetabular impingement (FAI) is a proliferative musculoskeletal diagnosis in young adults. The purpose of the current study was to investigate the effect of challenged walking on gait mechanics in individuals with FAI compared to matched asymptomatic individuals. Two groups of seven underwent gait analysis during level, incline and decline walking. Kinematic data and surface electromyography were recorded using standardized procedures. Sagittal plane kinematics and activation of the gluteus maximus and medius were calculated. A 2-way mixed methods ANOVA identified differences in kinematics and neuromuscular activations. Significant main effects for condition were found for all biomechanical and neuromuscular variables (p≤0.05). No significant between group differences were found; however, moderate to large effect sizes were identified for sagittal plane hip range of motion, peak hip extension, gluteus maximus and gluteus medius. Results suggest that challenged walking may elicit novel biomechanical and neuromuscular alterations between individuals with FAI and asymptomatic controls.


title: AN ANALYSIS OF THE HUMAN RIGHTS APPROACH TO CLIMATE CHANGE: THE RIGHT TO A HEALTHY ENVIRONMENT, INTERGENERATIONAL EQUITY AND CLIMATE LITIGATION

contributor:
Faculty of Law
Master of Laws
Lucie Guibault
Camille Cameron
David VanderZwaag
Sara Seck
Not Applicable
Not Applicable
Not Applicable

subject:
Climate Litigation
Intergenerational Equity
Right to a healthy environment
Human rights and climate change

abstract: Climate change litigation is a viable tool in the fight against climate change. For the past 2 decades, climate litigation has largely been based on torts and administrative law. However, courts have recently been quite receptive to human rights arguments in climate cases, thereby necessitating recognition of the human rights approach as an important facet of climate litigation. It is important for intergenerational equity to be integrated into the human rights approach to climate change. One of the major benefits of intergenerational equity to the human rights approach is its potential to catalyze the recognition of the right to a healthy environment. The conclusion in this thesis is that the right to a healthy environment and intergenerational equity are two vital components of the human rights approach to climate change and are necessary to advance the human rights approach to climate litigation.


title: Human Health Risks Associated With Wastewater Treatment in Arctic Canada

contributor:
Interdisciplinary PhD Programme
Doctor of Philosophy
Dr. Corinne Schuster-Wallace
Dr. Lynne Robinson
Dr. Lisbeth Truelstrup Hansen
Dr. Daniel Rainham
Dr. Rob Jamieson
Received
Yes
Yes

subject: Indigenous Health

subject: Arctic

subject: Rural and Remote Health

subject: Quantitative Microbial Risk Assessment (QMRA)

subject: Water, Sanitation, and Hygiene (WASH)

abstract: This dissertation provides the first estimates of microbial health risks attributable to wastewater treatment systems in Arctic Canada. A participatory quantitative microbial risk assessment was designed to model a range of exposures scenarios and mitigations. In Chapter Two, the state of knowledge on wastewater treatment, exposure pathways, and waterborne disease in Inuit and Arctic communities is reviewed. A conceptual model is developed to guide the risk assessment. Chapter Three describes a screening-level quantitative microbial risk assessment model and estimates the probability of acute gastrointestinal illness (AGI) associated with worst-case exposure scenarios in five Nunavut case study sites. An annual incidence rate of 5.0 cases per person is predicted in Pangnirtung, where a mechanical treatment system discharges to a marine environment at low tide.  An incidence rate of 1.2 cases per person is predicted in Naujaat, where an undersized passive system is used, with most cases predicted during spring freshet. These results are considered high and moderate, respectively, in comparison to literature-based estimates of AGI in the region. In Chapter Four, a more in-depth stochastic model is used to characterize risk for inferential Arctic wastewater exposure scenarios and results are compared to a global health guideline (10-3 annual risk of waterborne AGI). The 75th percentile risk level exceeds the guideline in three scenarios: shore recreation near mechanical treatment sites during low tide; consumption of shellfish harvested near mechanical treatment sites during low tide; and wetland travel near passive treatment sites during spring freshet. Rotavirus and Salmonella spp. project the highest risk of the six enteric pathogens included in the model. Two forms of mitigation are also evaluated (improved treatment, behavioural change), and both are shown to potentially reduce risk to varying degrees. These findings suggest that wastewater exposures may be contributing to high AGI rates in some Arctic communities. Passive systems with controlled discharge and risk communication are recommended as the most appropriate wastewater treatment solution. This research has immediate application in Arctic regions and contributes to the broader socio-ecological understanding of water, sanitation, and health.


title: Fast Preprocessing for Optimal Orthogonal Range Reporting and Range Successor with Applications to Text Indexing

contributor:
Faculty of Computer Science
Master of Computer Science
Michael McAllister
Travis Gagie
Norbert Zeh
Meng He
Not Applicable
Not Applicable
No

subject:
orthogonal range search
geometric data structures
orthogonal range reporting
orthogonal range successor
sorted range reporting
text indexing
word RAM

abstract: Under the word RAM model, we design three data structures that can be constructed in $O(n\sqrt{\lg n})$ time over $n$ points in an $n \times n$ grid. The first data structure is an $O(n\lg^{\epsilon} n)$-word structure supporting orthogonal range reporting in $O(\lg\lg n+\occ)$ time, where $\occ$ denotes output size and $\epsilon$ is an arbitrarily small constant. The second is an $O(n\lg\lg n)$-word structure supporting orthogonal range successor in $O(\lg\lg n)$ time, while the third is an $O(n\lg^{\epsilon} n)$-word structure supporting sorted range reporting in $O(\lg\lg n+\occ)$ time. The query times of these data structures are optimal when the space costs must be within $O(n\polylog n)$ words. Their exact space bounds match those of the best known results achieving the same query times, and the $O(n\sqrt{\lg n})$ construction time beats the previous bounds on preprocessing. We also apply our results to improve the construction time of text indexes.


title: MICROGLIA RESPONSES IN A RAT MODEL OF CHRONIC SLEEP RESTRICTION

contributor:
Department of Medical Neuroscience
Doctor of Philosophy
Dr. Mark Opp
Dr. Kazue Semba
Dr. Ying Zhang
Dr. George S. Robertson
Dr. Kazue Semba
Received
Not Applicable
Yes

subject:
Sleep deprivation
Inflammation
Cytokines
Immunohistochemistry
Neuroscience
Iba1

abstract:
Recent research suggests that the brain and body adapt to chronic sleep restriction (CSR) resulting in only modest attempts to recover lost sleep and negatively impacting health over time. Microglia, the immune cells of the brain, are possible mediators of this adaptation to CSR, yet their responses to CSR in key keep/wake regulatory brain regions remained to be characterized. Therefore, I investigated microglia responses to CSR using a rat model featuring slowly rotating wheels (3 h on/1 h off). Adult male rats were sleep restricted for 3, 27 or 99 h, or 99 h followed by 6 days of undisturbed recovery sleep along with several time-matched housing and activity control groups.
First, using the microglia marker ionized calcium-binding adaptor molecule-1 (Iba1), I found that the number of Iba1-immuoreactive cells and the density of Iba1 immunoreactivity were increased in 4/10 brain regions involved in sleep/wake regulation and cognition after 27 and/or 99 h of CSR. Neither microglia proliferation nor impaired blood–brain barrier permeability appeared to contribute to the increased Iba1 immunoreactivity. In the frontal cortex and lateral hypothalamus, two brain regions that showed increased Iba1 in response to CSR, Iba1+ microglia appeared ramified in all treatment groups with no effect of CSR.
Next, I demonstrated using qRT-PCR that after 27 h, but not 99 h, of CSR, mRNA levels of the anti-inflammatory cytokine interleukin-10 were increased in the frontal cortex. Pro- inflammatory cytokine mRNA levels (tumor necrosis factor-α, interleukin-1β, and interleukin-6) were unchanged. Furthermore, cortical microglia were not immunoreactive for several inflammatory markers but were immunoreactive for the P2Y12 receptor. Collectively, these results suggest a homeostatic microglia phenotype.
Finally, I investigated the functional role of CSR-responsive microglia by examining the structural relationship of microglia with two major populations of sleep/wake-regulatory neurons, namely melanin-concentrating hormone (MCH) and orexin (ORX) neurons in the lateral hypothalamus. Microglia were found in close contact with both MCH and ORX neurons and this microglia–neuron contact remained unaltered following CSR.
These results suggest that microglia respond to CSR while remaining in a physiological state and may contribute to the previously reported homeostatic and adaptive responses to CSR.


title: Active River Area (ARA) Framework Refinement: Developing Frameworks for Terrace and Meander Belt Delineation and Defining Optimal Digital Elevation Model for Future ARA Delineation

contributor: School for Resource & Environmental Studies

subject:
GIS
Riparian Areas
Fluvial Geomorphology

abstract: The Active River Area (ARA) is a spatial approach for identifying the extent of functional riparian areas, with five components (floodplains, terraces, riparian wetlands, meander belts, material contribution zones). Given the limitations in terms of input data quality and methodology, this framework cannot specifically differentiate terraces from floodplains and identify the river meander extent. To address these limitations in the ARA framework, this study developed a floodplain and terrace separation framework and a meander belt delineation framework. Their applicability was tested in two study watersheds in New Brunswick. Moreover, to determine the optimal input DEM for future ARA studies, this study developed an accuracy-efficiency tradeoff analysis framework and assessed ARA outputs derived from a range of DEM inputs for accuracy and efficiency. It has been found that 5-m smoothed LiDAR DEM is best able to balance final ARA accuracy and data processing efficiency and ultimately recommended for future ARA delineations.


title: The Province of (Substantive) Legitimate Expectation in Nigeria's Tax Administration: A Law and Policy Evaluation

contributor:
Faculty of Law
Master of Laws
Professor Lucie Guibault
Professor Colin Jackson
Professor Olabisi Akinkugbe
Professor Kim Brooks
Not Applicable
Not Applicable
Not Applicable

subject:
Tax
Tax Administration
Legitimate Expectation
Discretion
Judicial Review
Tax Law

abstract: The interplay between tax administration and legitimate expectation has been the subject of debate and scholarship in many jurisdictions. Questions around how much discretion tax authorities should be allowed and whether courts should uphold the (substantive) legitimate expectations of taxpayers – by implication, bind the tax authority – when the tax authority reverses itself on a guidance, promise, position, etc. feature prominently in this conundrum. In Nigeria, the disposition of both the tax authority and the court appears to lean towards outright dismissal of legitimate expectation. Put differently, it seems that the tax authority does not consider itself bound by its previous position, perhaps, irrespective of the implications for the taxpayer. The court likewise does not deem the tax authority bound, especially when that previous position appears to contradict the relevant statute, hence no legitimate expectation. This thesis puts these assertions to the test, in order to bring out better clarity on the subject. I argue that, as far as Nigeria is concerned, there are both legal and policy bases for upholding or enforcing tax-based legitimate expectation. Relying on Nigerian and English authorities, I discuss the possibilities of streamlining the enforcement of tax-based legitimate expectation in Nigeria. I also discuss the various factors that militate against the application of the doctrine. From a policy perspective, I argue that the tax authority respecting/upholding its commitments to taxpayers, in appropriate cases, could be more consistent with some important aspects of Nigeria’s National Tax Policy – such as fairness, neutrality, certainty and administrability – and, perhaps, enhance the overall value base of Nigeria’s tax system.


title: ℞ITUAL OBJECTS: SPIRITS, HEALTH & DECOLONIZING THE STUDY OF AFRICAN POWER FIGURES

subject:
Africa
Diaspora
Traditional Religion
Traditional Medicine
Power Figures
Stigma

abstract:
Composite ritual power objects are used throughout West and Central Africa and across
the Black Atlantic. These sacred objects are composed of a material figure, medicines, and spirit
power, and can be constructed to perform a variety of functions from generating luck or love to
warding off illness or seeking revenge. As part of the material culture of holistic healing in African and Disaporic traditional religions, these figures act as important objects within traditional medical systems. However, they, like the traditions of which they are a part, have long met with stigma in the West, being outlawed, destroyed, demeaned, and dismissed by those who thought them heretical, barbaric, irrational, and unmodern. Western assumptions have tended to interpret power figures and their traditions according to Western categories of what constitutes art, religion, and medicine, leading to flawed and incomplete representations by outsiders. This study reveals that all aspects of power figures – from the physical figures, to the medicines, and the spirits – have been subjected to the same stigma. Through object and content analysis of these sacred objects, their ingredients, and their records in museums, art galleries, popular culture, public discourse, and legal documentation, and also in botánicas, ritual shops, and ritualists’ blogs, this work aims to produce a decolonized study of these sacred objects – one that attempts as much as possible to see these figures and their power on their own terms – while also providing insight into what these objects can teach us about how we might heal.


title: CHARACTERIZATION OF AAV2-GCAMP3 FOR FUNCTIONAL IMAGING IN RETINAL GANGLION CELLS

contributor:
Department of Medical Neuroscience
Master of Science
Dr. Brennan Eadie
Dr. Kazue Semba
Dr. Frank Smith
Dr. William Baldridge
Dr. Balwantray Chauhan
Received
Not Applicable
Yes

subject:
Calcium
Retinal ganglion cells
Adeno-associated viral vector
In vivo imaging
Retina

abstract: The loss of retinal ganglion cells (RGCs) is the hallmark of optic neuropathies, such as glaucoma. Monitoring RGC function and subsequent dysfunction over time is an invaluable tool in experimental optic neuropathies and potentially in clinical disease. This research characterizes a non-invasive technique for delivering a functional fluorescent marker to RGCs to optically record function. We tested the hypothesis that the genetically encoded calcium (Ca2+) indictor, GCaMP, could be exogenously delivered to the retina with intravitreal injection and produce functional GCaMP3 proteins capable of responding to external stimuli. C57Bl/6 mice were injected with an AAV2-CAG-GCaMP3 viral vector and monitored weekly with in vivo confocal scanning laser ophthalmoscopy over five weeks to quantify the transduction of the virus into retinal cells. Following five weeks, Ca2+ imaging was performed in retinas of a subset of mice injected with AAV2-CAG-GCaMP3 and well as in Thy1-GCaMP3 transgenic mice. Transient increases of intracellular Ca2+ evoked by 50 μM kainic acid (KA) treatments were recorded. In another subset of AAV2-GCaMP3 injected mice, retinas were processed for immunohistochemistry with antibodies against RBPMS (a marker for RGCs), ChAT (a marker for cholinergic amacrine cells), and GFP (to enhance the GCaMP signal). In all injected mice, labelled cells were visible with in vivo imaging one-week following injection. The density of transduced cells increased significantly over five weeks, and the labelling persisted to six-months post-injection. Ex vivo Ca2+ imaging demonstrated that the transduced GCaMP3 was functional in response to treatments of 50 μM KA. The transduced GCaMP3 produced similar mean KA-induced-transients when compared to Thy1-GCaMP3 transgenic mice. Immunohistochemical analysis determined that a mean (SD) of 79 (6)% of GFP-positive cells were RBPMS-positive, 9 (4)% were ChAT-positive, and 12 (7)% did not co-localize with either RBPMS or ChAT. This research demonstrates that exogenous functional fluorescent markers such as GCaMP can be delivered to the retina, be visualized with in vivo imaging and be used to record functional responses from RGCs. It paves the way for examining single cell functional responses, both in vivo and non-invasively, for evaluating experimental optic neuropathies and gauging the effects of potential neuroprotective avenues. Finally, it is proof-of-principle for translation to clinical medicine.


title: DISMANTLING THE GREEN MACHINE: A CRITICAL REFLECTION ON TECHNOLOGY AND ECOMODERN ENVIRONMENTAL POLICY

contributor:
Interdisciplinary PhD Programme
Doctor of Philosophy
Dr. Warren Mabee
Dr. Lynne Robinson
Dr. Peter Duinker
Dr. Gordon McOuat
Dr. Peter Tyedmers
Not Applicable
Yes
Not Applicable

subject:
sustainability
green technology
ecomodern
LCA
wood biomass
wood pellets
philosophy of technology
ecological economics
bioenergy

abstract: Addressing the scale of negative environmental changes from the rapid expansion of human populations and economic growth is a critical policy issue in the twenty-first century. Government and corporate responses are directed towards engineering a new industrial revolution through the design and deployment of green technologies and products. Despite the widespread adoption of this ecomodern approach, empirical data show environmental conditions continue to deteriorate and are poised to continue declining into the middle of this century and beyond. Case studies on the environmental performance of wood bioenergy systems were used demonstrate the mechanics of ecomodern environmental policy. Insights from the philosophy of technology were used to conceptualize the Green Machine, a macro-technology system encompassing ecomodern policies. A critical reflection was undertaken to reconcile the technological optimism of ecomodern policies with the reality of worsening global environmental challenges and to underscore the limitations of pursuing green technology as the sole solution.


title: STUDY OF THE SURFACE REACTIVITY OF Ni-RICH POSITIVE ELECTRODE MATERIALS FOR Li-ION CELLS

contributor: Department of Physics & Atmospheric Science

subject:
Li-ion batteries
Cathode materials
Air stability
Core-shell materials

abstract: The growth of surface impurities on positive electrode materials used in Li-ion cells is detrimental to the electrochemical performance of the cells. Ni-rich layered lithium metal oxides are promising materials for the production of high capacity Li-ion batteries but are prone to surface impurity growth. For this reason, it is common in industry to wash these materials. However, very little mechanistic understanding of the reaction between the materials and the aqueous solution used for washing is known. In this work, the effects of exposing Ni-rich positive electrode materials to aqueous solutions were studied. Additionally, core-shell materials containing a gradient-concentration of Ni were tested for the possibility to increase the air stability of Ni-rich positive electrode materials with minimal compromise to electrochemical properties. By improving both the washing process for Ni-rich materials and increasing their air stability, Ni-rich positive electrodes could reach high performance levels which are currently, commercially unattained.


title: The Use of NIRS in Monitoring Lower-Limb Motor Activation: A Study Comparing a Mobile and Research-Grade System

contributor:
School of Health & Human Performance
Master of Science
Dr. Tim Bardouille
Nadine MacDonald
Dr. Shaun Boe
Dr. Aaron Newman
Dr. Heather Neyedli
Received
Not Applicable
Not Applicable

subject:
NIRS
mobile device
near-infrared spectroscopy

abstract: Near-infrared spectroscopy (NIRS) is an optical imaging tool used to monitor neural activation through detecting changes in oxygenated and deoxygenated hemoglobin. This study aims to determine whether NIRS can be used to monitor neural activity associated with lower limb movements, as well as comparing the capacity to do so between a research-grade and mobile system. This marching task used was expected to elicit medial neural activity in the sensorimotor cortex. The blocks in this study differed based on the system used (NIRScout or Axem), as well as the position placement of the mobile device. Both devices showed changes in activation associated with lower limb moments. The research-grade device showed a greater capacity to detect change in activity, and the mobile device showed more expected patterns of activation for lower limb movements. Knowledge gained from this study contributes to the development of mobile NIRS systems in monitoring motor-related neural activation.


title: The Development, Evaluation, and Implementation of a Motivations Scale in the Context of the Second Screen Experience

contributor:
Interdisciplinary PhD Programme
Doctor of Philosophy
Dr. Anabel Quan-Haase
Dr. Lynne Robinson
Dr. Evangelos Milios
Dr. Sandra Toze
Dr. Vivian Howard
Dr. Anatoliy Gruzd
Received
Not Applicable
Not Applicable

subject:
HCI
Scale creation
Second screen
Second screen experience

abstract:
Increasingly TV viewers are engaging in the Second Screen Experience (SSE): using secondary screens to discuss television shows while watching them. This research explores motivations to engage in the SSE through analysis of the results of an online survey of second screen (SS) users. The core component of this survey was the Second Screen Experience: Motivations Scale (SSE-MS), a new 30-item questionnaire developed as a main element of this research. The goal was to assess motivations of engaging in the SSE, and to explore factors such as Demographics, TV Viewing Habits, and SS Use variables that are related to the use of the SS (what, where, when, and how the SS is used).
This research was based on the Uses and Gratifications (U & G) framework and conducted in three stages: (1) scale development, (2) creation, and (3) testing on a sample of 450 participants. The SSE-MS contained subscales assessing Cognitive, Personal Identity, Social Integration, and Diversion motivations via the SSE.
All motivations were endorsed by participants, with the endorsement of Diversion slightly higher than Cognitive, which was slightly higher in turn than Personal Identity and Social Integration. Interestingly, living arrangements and occupations were related to the use of a SS to fulfill needs, while age, gender, education, income, and place of residence were not. With regard to TV Viewing Habits, the use of the SS to fulfill needs was related to the social situation of TV viewing (e.g., with family, alone), the choice of TV programming (i.e., genres), and the emotional connection with TV shows (e.g., shows followed on social media). Finally, for SS Use, the study revealed that the use of the SS to fulfill needs was related to the physical company, and the type of social media outlets (e.g., blogs, forums), but not to other activities (e.g., work, shopping) or to the type of SS (e.g., dual screens, split screens).
In addition to contributing to research on the SSE, this research produced a valid, reliable, and easy to use scale capable of determining the motivations for using a SS to talk about TV while watching that TV.


title: Marine Aerosol Physical Properties and Influences by Meteorology in the North Atlantic Ocean

subject:
North Atlantic Ocean
Boundary Layer Meteorology
New Particle Formation
Aerosol Growth
Marine Aerosols

abstract: Marine aerosols play an important role in earth’s climate, but their effects remain highly uncertain due to a poor understanding of their sources, properties, and atmospheric processing, partly due to limited measurements. The Coastal-Fog (C-FOG) study investigated the processes controlling the formation and properties of fog in the North Atlantic Ocean. As part of this study, aerosol particle size distributions and chemical composition were measured off the shore of the northeastern United States and Atlantic Canada, and used to investigate the sources and processes affecting the observed aerosols. Processed marine air during the study was characterized by single and bi-modal aerosol size distributions. Aerosols in the port city of St. John’s, Newfoundland reflected local emissions built up due to poor ventilation, whereas aerosols in Halifax, Nova Scotia were lower in concentration because the harbour is more spread out. Finally, two particle growth events were observed. The first event captured the appearance of 10 nm particles that grew to 30 nm over 4 h. These aerosols appeared to be newly formed in the upper portion of the boundary layer with influence from the free troposphere before subsiding to the surface. In the second event, 45 nm particles grew to 70 nm over 8 h. The growth of these aerosols was most likely due to the direct condensation of organic vapours emitted from boreal forests and/or the ocean. Our observations provide important insight into the processes affecting marine aerosols and highlight the crucial role of boundary layer meteorology.


title: THE FUNCTIONS OF MOUSE SPINAL V3 INTERNEURONS IN LOCOMOTION

contributor:
Department of Medical Neuroscience
Doctor of Philosophy
Dr. Ronald Morgan Harris-Warrick
Dr. Kazue Semba
Dr. Turgay Akay
Dr. Victor Rafuse
Dr. Ying Zhang
Received
Yes
Yes

subject:
V3 interneurons
spinal cord locomotor circuit
locomotion
sensorimotor circuit
spinal cord injury

abstract: V3 interneurons (INs) are a major group of glutamatergic commissural neurons in the mouse spinal cord. They directly innervate motor neurons (MNs) as well as other ventral INs. Although it has been shown that V3 INs are crucial in generating stable and robust rhythmic locomotor activities, the mechanisms underlying their functions are still unclear. In my current study, I delete the expression of Vesicular Glutamate Transporter 2 (vGluT2) in V3 INs in Sim1Cre/+;vGluT2 flox/flox (V3OFF) mice, and systematically examine their locomotor behaviours, including their gaits at various treadmill speeds, as well as their kinematics and muscle activities in different locomotor tasks. Firstly, I identify a subset of V3 INs that might regulate the coordination of fore- and hind-limbs for trotting movements. Secondly, I find that V3 INs have task-dependent functional roles in regulating proximal or distal joints. They facilitate hip joint movements in all locomotor tasks, while only regulating distal joint activities in weight-bearing behaviours. In addition, using optogenetic tools, I also investigate the functions of V3 INs in fictive locomotion of the neonatal spinal cord. In combination with computational modelling studies, we provide convincing evidence that V3 INs contribute to the synchronization of the left-right locomotor outputs by providing mutual excitation between the extensor centres in the left and right central pattern generator (CPG) circuits. Thus, my study reveals that spinal V3 INs potentially have multiple functional subpopulations that play various specific and critical roles in regulating locomotor behaviours under different conditions.


title: Loan Pricing in Interest Rate Liberalization in China

contributor:
Department of Economics
Master of Arts
Casey Warman
Kuan Xu
Yulia Kotlyarova
Christos Ntantamis
Casey Warman
Not Applicable
Not Applicable
Not Applicable

subject:
Interest rate liberalization
loan pricing strategy
information advantage
adverse selection
moral hazard

abstract: In order to find how the process of interest rate liberalization influences the pricing strategy of dominant lenders in China’s loan market and their mark-up power, I establish a pricing model to examine the effect of level of discretion in an oligopoly loan market on the incumbent lenders’ entry-deterrence pricing strategy. In my theoretical models, I find two critical propositions: first, with perfect information, the mark-up power of the interest rate in the primary market decreases as the level of discretion in price-setting increases. This effect is mitigated, however, by moral hazard. Second, with the existence of adverse selection, an increase in the level of discretion indicates that the incumbent lenders can have more room to set the pool-pricing interest rate in the primary market. Moreover, I provide empirical evidence for decreasing mark-up pricing in China’s loan market as loan rate liberalization completes, consistent with the prediction of my model.


title: HYDROLOGIC ASSESSMENT OF A SMALL MARITIME HYDROMETRIC MONITORING NETWORK USING A PROCESS-GUIDED CATCHMENT CLASSIFICATION SYSTEM

contributor:
Department of Civil Engineering
Master of Applied Science
Barret Kurylyk
Barret Kurylyk
Mark Greenwood
Rob Jamieson
Not Applicable
Not Applicable
No

subject:
catchment classification
hydrometric review
data transfer
data-limited

abstract:
The National Hydrometric Program, operated by the Water Survey of Canada, is the primary source of surface water quantity data in Canada. The network is cost-shared between the federal and provincial governments, and decisions relating to station placement are made according to both federal and provincial interests. Nova Scotia is a small maritime province in Atlantic Canada with a relatively diverse climate and geology for its small size. The Nova Scotia hydrometric monitoring network currently consists of 31 stations. The overall objective of this study was to determine how well the current network captures the level of hydrologic variability expected in the province using a regional catchment classification scheme. To accomplish this, we developed a combined inductive-deductive catchment classification system and applied it to the province’s active monitoring network and 246 ungauged major watersheds. Initially, hydrologic signatures were used to quantify the catchment function of 47 long-term gauged catchments and to cluster similarly behaving catchments. We identified five generalized flow classes and then attempted to replicate this classification using a deductive-based decision tree framework with physiographic and meteorological explanatory variables. The validated decision tree was used to classify the active hydrometric network and 246 major watersheds in the province. The network was assessed to determine how well it covered the expected hydrologic variability in the major watersheds across the province. The results indicated that current active hydrometric monitoring network does not adequately capture the range of hydrologic variability within this region; three of the five primary flow regimes observed in the province are not well represented by the active
viii
network. The analysis also illustrated that the stations in the active monitoring network are not evenly distributed among the five generalized flow classes seen in Nova Scotia. The decision tree proved to be a useful tool for understanding the current network’s coverage and could also be easily applied by practitioners to identify appropriate donor catchments for ungauged watersheds.


title: Quantifying coastal cliff retreat using Structure-from-Motion photogrammetry in the Minas Basin, Nova Scotia

contributor:
Department of Oceanography
Master of Science
Markus Kienast
Markus Kienast
Danika van Proosdij
Timothy Milligan
Paul Hill
Not Applicable
No
Not Applicable

subject:
Photogrammetry
Cliff retreat
Nova Scotia
Sandstone cliff
air photos
Minas Basin
DSAS
aerial photography

abstract: Rates of retreat of cliffed coastlines are increasing around the globe, but the causes of observed increases are unclear.  Lack of understanding complicates assessment of the risks to coastal infrastructure associated with rising sea levels.  The frequencies and magnitudes of the coastal cliff erosion events that combine to produce overall, longer-term rates of retreat historically have been poorly constrained because observations generally were not possible on the time scales associated with major terrestrial and oceanographic forcings, which include, among others, heavy precipitation, repeated freeze-thaw cycles, and large waves associated with high water levels. To address mis-match between observational time scales and time scales of event-driven erosion, a two-part study is undertaken.  In the first part, analysis of archived aerial photographs is used to produce approximately decadal estimates of coastal retreat over the past 8 decades at Thomas’ Cove Coastal Reserve in Economy, Nova Scotia.  In the second part, Structure-from-Motion (SfM) analysis is used to survey actively eroding cliffs at Thomas’ Cove. On multiple visits between June 2018 and October 2019, photographs were taken with a camera mounted on a small Remotely Piloted Aircraft (sRPA).  Images are used to create three-dimensional point-clouds, Digital Surface Models (DSMs) and orthomosaics with Pix4D, a commercially available SfM software package. DSMs and orthomosaics are used to map the position of the cliff top through the observation period.  Calculated short-term retreat rates are compared to decadal-scale retreat rates for Thomas Cove determined from archived aerial photos and previous studies in the area. These rates indicate that present retreat rates are statistically similar to long-term averages and higher than rates observed over the past four decades. Additionally, volume change is calculated using GIS techniques and found to be consistent with values calculated in the same region by Wilson et al, 2017.


title: Lower Respiratory Tract Infections in Multiple Subgroups of Immunocompromised Children: A Retrospective Cohort Study

contributor: Department of Community Health & Epidemiology

abstract: Lower respiratory tract infections (LRTIs) are more likely to have severe impact on immunocompromised children. Hence, we determined among immunocompromised children (1) the incidence of LRTI hospitalizations, (2) microbiological etiology and clinical burden of LRTI hospitalizations, and (3) association between baseline characteristics and LRTI hospitalizations. A retrospective cohort study of children age < 16 years treated at IWK Health Center 2004-2014 for immunocompromising conditions was conducted. We followed them from date of diagnosis of immunocompromise until first LRTI hospitalization or death or end of study period or immunocompromised status. The incidence proportion and crude incidence of LRTI hospitalizations was 15.8% and 52.4 per 1,000 person-years. The incidence was relatively higher among immunology, oncology and hematology groups. Viruses were most common, followed by bacteria and fungi. Clinical burden was high among patients. Log-rank tests and hazard ratios were statistically significant for types of immunocompromising disorders, age at diagnosis, and gender.


title: Characterizing Arsenic Speciation and Metallomic Profiles in Toenail Samples of Atlantic Canadians: A Matched Case-Control Study of Breast, Cervical, Prostate, Urinary, and Skin Cancers

subject:
Arsenic Speciation
Trace Metal Exposure
Toenail Biomarkers
Cancer
Atlantic Canada

abstract: Chronic exposure to arsenic and metals has been associated with cancer risk.  The research objectives were to 1) characterize the profiles of arsenic speciation and metallomes in the toenails of several cancer groups and healthy participants; 2) determine whether there is an association between the profiles of arsenic speciation and metallomes and cancers; while 3) adjusting for potential confounders.  Total concentrations of metals and the levels of arsenic species were measured using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and High Performance Liquid Chromatography (HPLC).  The levels and profiles of arsenic speciation and metallomes were compared between cases and controls using MANOVA in adjusted and unadjusted analyses.  The profiles of arsenic speciation and metallomes were significantly different between cancer cases and controls.  Arsenic methylation capacity may be inversely associated with cancer risk.  Toenail arsenic speciation and metallomes (e.g., zinc levels) may be an important biomarker for cancer risk.  Further research is needed to use toenails as a prognostic measure of trace metal-induced cancer.


title: PROPOSING A CONSTRUCTIVIST APPROACH TO RESOLVING TRADE CONFLICTS UNDER THE AFRICAN CONTINENTAL FREE TRADE AREA AGREEMENT (AfCFTA): A CROSS-JURISDICTIONAL ANALYSIS

contributor:
Faculty of Law
Master of Laws
PROF. LUCIE GUIBAULT
PROF. OLABISI AKINKUGBE
PROF. PHILLIP SAUNDERS
PROF. DIANA GINN
Not Applicable
Not Applicable
Not Applicable

subject:
AfCFTA
Constructivism
Dispute Resolution Mechanism

abstract: Essentially a research of an interdisciplinary nature, this thesis seeks to carefully combine budding thoughts from two different areas of scholarship in order to present a unique underlying perspective. On the one hand, there is the study of conflict and its resolution from such intrinsic standpoint as to appreciate it as constitutive of the Society with the aim of achieving more wholesome outcomes that accentuates the uniqueness of each society. On the other hand, the recent coming to force of AfCFTA has left so much for scholars to grapple with, including how its dispute settlement regime could reflect more on the African character. In merging these two discourses, this thesis aims to give context to the former while proffering theoretical basis to the latter in a seamless symbiotic flow.


title: INFLUENCE OF LAND-USE INTENSITY ON SOIL NEMATODE COMMUNITIES AND THEIR RELATIONSHIP TO RHIZOCTONIA SOLANI DISEASE SUPPRESSION

contributor:
Faculty of Agriculture
Master of Science
Gordon Price
Adam Foster
Tudor Borza
Derek Lynch
Tandra Fraser
Not Applicable
Not Applicable
Not Applicable

subject:
Soil
Nematode
Rhizoctonia solani
Land-use intensity

abstract:
ABSTRACT
	Soil organic matter (SOM) degradation linked to intensive management across PEI may negatively impact soil nematode communities and disease suppression. Soil nematode communities (Chapter 2), Rhizoctonia solani soil concentrations (Chapter 3), and soil properties were assessed across three land-use intensities (pasture/forest systems<four year grain rotations<three year potato rotations) from PEI field soils in 2018 and 2019.  Nematode faunal indices were then tested for their ability to predict soils suppressive to R. solani disease in soybeans (Chapter 3). Nematode indices reflected degraded nematode communities in high intensity potato rotations, while the community as a whole responded to low intensity vegetation gradients. R. solani field soil concentrations were negatively correlated with several indicators of SOM content, while POM C and ACE protein were positively correlated regardless of environmental conditions. Although nematode faunal indices were not good indicators of R. solani suppressive soils, the fungivore Aphelenchidae was positively associated with hypocotyl disease ratings.


title: Geometric Horizons in the Szekeres Spacetime

contributor: Department of Mathematics & Statistics - Math Division

subject:
Gravitation
Relativity
Black Holes
Horizons

abstract:
A new conjecture for geometric horizons has been introduced which may provide a
potential alternative to using apparent horizons and related surfaces for analyzing the
dynamics of black hole spacetimes. In particular, using two examples of black hole
formation in a collapsing universe in the Szekeres spacetime, the formation, evolution,
and detection of geometric horizons are shown. In addition, a function for detecting
apparent horizons in the Szekeres spacetime is also considered, and it is shown that
the apparent horizon in the Szekeres model, is in fact, a geometric horizon. The
Cartan-Karlhede algorithm for determining local equivalences of spacetimes is used
to compute an invariant frame in the Newman Penrose frame formalism, and Cartan
invariants derived from the spacetime in this frame are shown to detect the geometric
horizons under various conditions on the curvature tensors of the spacetime. One
model for primordial black hole formation and another for galactic black hole formation
are considered with non-zero cosmological constants, generalizing work published
previously on these models with zero cosmological constant. Future work utilizing geometric
horizons may provide benefits in gravitational wave research involving black
hole mergers.


title: Next Generation Adaptive Optics

subject:
Adaptive Optics
MEMS
IC
CMOS
QSO
Deformable Mirror

abstract:
Adaptive Optics (AO) is an integral part of modern astronomy. Current systems are pushing the limits of large diameter telescopes to achieve near diffraction limited performance. Historically, AO systems have been limited to a small field-of-view, a constraint that must be addressed to achieve the full capability of next-generation extremely large telescopes (ELTs) (e.g. Thirty Meter Telescope). As the size of the deformable mirror (DM) scales to meet the requirements of these large diameter telescopes, traditional technologies commonly employed on smaller telescopes are reaching their breaking point in terms of the number of high voltage connections and the overall power dissipation of the DM system.

This thesis addresses the need for a scalable DM electronics driver topology in high actuator count applications and provides the foundation for a science case targeted at resolving star-formation dynamics in the host galaxy of hyper-luminous quasi-stellar objects (HLQSOs) using adaptive optics. The DM driver explored in this thesis is the first effort towards a scalable low-voltage integrated solution for pairing with a low-voltage/current micro-electro mechanical system (MEMS) DM. A 9-channel prototype driver is shown experimentally to provide ±20 μm of stroke on a Lorentz force MEMS actuator using a ±5 mA current in a 0.1T magnetic field.

One of the main applications for this technology is future AO systems destined for ELTs, which will provide the resolution and sensitivity required to study host galaxy properties of systems containing extremely bright QSOs. In the second half of the thesis, a population of rare and extremely bright HQSOs and their host galaxy environments were explored to understand how the relationship between QSO luminosity and host galaxy IR luminosity scales to the most luminous HQSOs. This thesis
finds that QSOs can continue to become more luminous while the host galaxies have reached their maximal SFR, and that only approximately 1/3 of our galaxies truly are abnormally luminous after accounting for the general trend in increasing LUV
with LIR and the fractional of population expected have host galaxies in a starburst mode.


title: Social Stressors, Community Belonging, And Culture-Related Protective Factors Among Youth And Adults In First Nations Communities: Links With Psychological Distress

contributor:
Department of Psychiatry Research
Master of Science
Dr. Sherry Stewart
Dr. Sherry Stewart
Dr. Derek Fisher
Dr. Margot Latimer
Dr. Amy Bombay
Received
Not Applicable
Not Applicable

subject:
First Nations
culture
racism
aggression
bullying
traditional spirituality
cultural events
belonging

abstract: Secondary analyses of the 2015/16 First Nations Regional Health Survey (RHS) explored the pathways in which various social and cultural factors were related  psychological distress in First Nations youth (Study One) and adults (Study Two) living on-reserve in Canada. Multivariate analyses revealed that social stressors assessed in youth (i.e., bullying, cyberbullying) and adult (i.e., cyberbullying, physical aggression, verbal aggression, racism) were positively associated with psychological distress. In youth and adults, strong community belonging was associated with reduced psychological distress. Conversely, agreement that cultural events (for youth) and traditional spirituality (for adults) were important was associated with higher psychological distress. Amongst youth (Study One), strong community belonging protected against high levels of distress associated with bullying/cyberbullying. Amongst adults (Study Two) strong community belonging protected (moderated) against high distress levels associated with racism, but agreement that traditional importance of traditional spirituality increased (moderated) psychological distress levels associated with physical aggression.


title: Describing the Global Distribution and Health Response of Particulate Matter Using Modern Computational Tools

subject:
Air pollution
Particulate Matter
Health Effects
Atmospheric Modeling
Remote Sensing

abstract:
Atmospheric aerosols have important impacts on climate and human health. This thesis advances our knowledge of the 3-dimensional distribution of atmospheric aerosols by using state of the art tools and methods to new fields or new sources of data in three applications.
First, I use adjoint modeling to provide the global health response to fine particulate matter with a diameter < 2.5 μm (PM2.5) by implementing the Global Burden of Disease Project's Integrated Response Function. The response of global mortality to changes in local unit-mass anthropogenic emissions varied spatially by several orders of magnitude; the largest reductions in mortality for a 1 kg km-2yr-1 decrease in emissions were for ammonia and carbonaceous aerosols in Eastern Europe. When comparing relative responses, the greatest reductions in mortality for a 10% decrease in emissions were found for secondary inorganic sources in East Asia.
Next, I applied the same adjoint to assimilate CALIOP Lidar profiles. Comparing mean extinction height (Zα) between the baseline simulation and two optimised simulations to CALIOP observed Zα, both optimisations improved the slope and offset of a linear fit across AEROCOM regions, but optimising initial conditions improved agreement (R = 0.78) compared to the baseline (R = 0.72) while optimising emissions decreased agreement (R = 0.65). In a global comparison of AOD, the optimised emissions greatly improved agreement with observations in the Sahara in January, but failed to capture the overall underestimate of AOD seen almost everywhere.
Finally, I used the modern machine learning framework Tensorflow to compute a high resolution (0.01°x0.01°) map of probability distributions of PM2.5 fitted to ground monitoring data from the World Health Organization's cities database. This model achieved an average correlation R2 of 0.93 and an average RMSD = 5.00 μgm-3 in 10-fold cross validation. Because the model outputs probability distributions at each grid location, I was able to calculate a global probability density function for population exposure to PM2.5. Based on the global PDF, 83% of the world’s population exceeds the WHO guideline of 10 μgm-3.


title: Using Canadian Law to Prevent, Respond to and Remedy Maltreatment in Sport: Listening to and Learning from Athletes

contributor:
Faculty of Law
Master of Laws
A. Wayne MacKay
Lucie Guibault
Jocelyn Downie
Adelina Iftene
Received
Not Applicable
Not Applicable

subject: athlete abuse

subject: athlete maltreatment

subject: athlete wellbeing

subject: maltreatment in Canadian sport

subject: psychological maltreatment of athletes

subject: physical maltreatment of athletes

subject: sexual abuse of athletes

subject: sexual exploitation of athletes

subject: education on maltreatment

subject: neglect of athletes

subject: post-Nassar

subject: legal approaches to addressing abuse in sport

subject: law and policy on athlete maltreatment

subject: sport culture

subject: sport law

subject: sport priorities

subject: sport self regulation

subject: athlete eating disorders

subject: abuse by coach

subject: maltreatment prevention

subject: human rights and sport

subject: international human rights in sport

subject: qualitative athlete study

subject: non accidental violence in sport

subject: impacts of athlete maltreatment

subject: harms from athlete maltreatment

abstract: This thesis addresses maltreatment of athletes in Canada, in the post-Nassar era, by considering applicable law, policy, academic literature and a qualitative study. Athlete maltreatment may include: psychological, physical and sexual maltreatment, and neglect. Prevalence and impacts of maltreatment are examined. Legal and administrative options available to complainants are discussed, as well as applicable international human rights and child rights conventions, Canadian legislation, legal principles, and jurisprudence. An academic literature review provides maltreatment definitions in order to lay the groundwork for the discussion. Academic perspectives and proposals for redress are considered. A qualitative athlete study produced four key themes which may negatively impact athletes: lack of education on maltreatment, distorted priorities, self-regulation by sport organizations and a discriminatory sport culture. Fortunately, many athletes and academics are united in a mission to promote a new holistic vision that prioritizes the health and wellbeing of athletes rather than athletic victories.


title: Using High-Throughput Paleolimnological Methods to Evaluate the Distribution and Transport of Lead in Northeastern North America

contributor:
Department of Civil Engineering
Doctor of Philosophy
Sarah Dorner
Barret Kurylyk
Ian S. Spooner
Joshua Kurek
Graham Gagnon
Not Applicable
Yes
Yes

subject:
Lake sediment
Atmospheric transport
Lead
Paleolimnology

abstract: Using high-throughput paleolimnological methods, this thesis evaluated anthropogenic Pb deposition along a west-east transect from the Adirondack Mountains, New York, USA (ADIR) region, the Vermont-New Hampshire-Maine, USA (VT-NH-ME) region, and Nova Scotia, Canada (NS) region using 47 ^210^Pb-dated lake sediment records. This thesis reviewed the distribution and transport of trace metals at a global scale, developed a high-throughput analytical method to measure the elemental composition of low-mass aquatic sediment samples, developed a software package to visualize and analyze measurements from many lake sediment records, validated the sensitivity of elemental measurements in lake sediments to watershed-scale disturbance, and evaluated calculated elemental measures to deconvolute multiple sources of trace metals to lake sediment records. Finally, this thesis used focus-corrected Pb inventories to evaluate cumulative deposition and breakpoint analysis to inform west-east transport of Pb in northeastern North America. Peak Pb concentrations decreased from west to east (ADIR region: 52-378 mg kg^-1^, VT-NH-ME region: 54-253 mg kg^-1^, NS: 38-140 mg kg^-1^). Cumulative deposition of anthropogenic Pb also decreased from west to east (ADIR region: 791-1,344 mg m^-2^, VT-NH-ME region: 209-1,206 mg m^-2^, NS: 52-421 mg m^-2^). The initiation of anthropogenic Pb deposition occurred progressively later along the same transect (ADIR region: 1869-1900, VT-NH-ME region: 1874-1905, NS region: 1901-1930). Previous lead isotope studies suggest that eastern Canadian Pb deposition over the past ~150 years has originated from a mix of both Canadian and U.S. sources. The results of this thesis indicate that anthropogenic Pb from sources west of the ADIR region were deposited in lesser amounts from west to east and/or Pb sources reflect less population density from west to east. The timing of the initiation of anthropogenic Pb deposition in the NS region suggests that Pb from gasoline may be an important source in this region. The high-throughput methods developed in this thesis may further the application of paleolimnological studies to regional contaminant transport, contaminated aquatic sediment assessment, and water infrastructure design.