title: Sustainable Masonry: Mortar Containing Biochar and Recycled Aggregate in Concrete Blocks

contributor:
Green, Mark
Civil Engineering

subject:
Civil Engineering
Sustainable Engineering
Masonry

abstract:
The building and construction industry is the third-largest producer of CO2 in Canada. Additionally, emissions from this industry are expected to go up by more than nine megatonnes of carbon dioxide equivalent (Mt CO2 eq) by the year 2030. As such, we need to find ways to reduce the carbon footprint of the construction industry. Any decrease in the emissions of carbon from the construction industry will help improve the long-term sustainability of the industry and also help the environment.
Biochar is an excellent way of achieving carbon reductions. Biochar is made from wood waste using the process of slow pyrolysis, and it can be mixed with cement in construction to create potential carbon sinks. This study will focus on biochar as a cementitious additive for cement mortar. Biochar is added to the cement mortar in different proportions of cement by weight (1.25%, 2.5%, 5%, 7.5% 10% and 12.5%) to create small-scale specimens that are tested under compressive load after 7, 28, and 56 days. It is noticed that there is a slight reduction in strength as the proportion of biochar is increased when it is used as a cement replacement. Biochar also increases the absorption in cement mortar because of its ability to store water and release it slowly, which provides internal curing to the mortar, helping it gain strength over time.
The second part of this thesis examines recycled concrete aggregate for the production of concrete blocks. Ontario has one of the highest rates of production of concrete blocks in North America. In addition to using large amounts of raw material, concrete block fabrication produced concrete waste at the production facilities in the form of spillage and culled blocks that are not fit for use. This waste is generally sent to landfills. A novel way to reduce this waste is to reuse it to make new blocks. In this study, recycled concrete aggregate (RCA) procured from a block manufacturer is used to replace coarse aggregate in proportions of 10%, 25%, 50%, 75%, and 100% by volume of aggregate. The blocks are cast in the Queen’s University Concrete Lab and are tested for compression after 28 days. Results indicate that the use of RCA in blocks does not affect the compressive strength adversely.

abstract: M.A.Sc.


title: Crosstalk Signaling Between cAMP and Calcium on the Leading Edge of Migrating Human Arterial Vascular Smooth Muscle Cells

contributor:
Maurice, Donald H.
Biomedical and Molecular Sciences

rights: Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada

rights: ProQuest PhD and Master's Theses International Dissemination Agreement

rights: Intellectual Property Guidelines at Queen's University

rights: This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.

subject:
PDE1C
cAMP-signaling
vascular smooth muscle cells
calcium
adenylyl cyclases
cyclic nucleotide phosphodiesterases

abstract: Vascular smooth muscle cells (VSMCs) are phenotypically plastic. Thus, while the VSMCs in healthy blood vessels are ‘contractile’ and control vascular tone, these cells can increase their synthetic, migratory and proliferative capacities in response to vessel injury. While largely adaptive, actions of “synthetic” VSMCs can promote arterial wall thickening and contribute to atherosclerosis and vessel stenosis. Currently, vessel stenosis is reversed by percutaneous coronary intervention (PCI) and the placement of drug eluting stents (DES) coated with pan-cellular anti-proliferative agents. Although these approaches are effective, in-stent restenosis and thrombosis remain problematic, in part due to limited re-endothelialization. Thus, DESs coated with drugs targeting specifically synthetic VSMCs, but not the endothelium, might limit these problems. Since the cyclic nucleotide phosphodiesterase, PDE1C, a dual cAMP/cGMP hydrolyzing PDE, is exclusively expressed by synthetic VSMCs and regulates their synthetic, migratory and proliferative actions, it may represent a valid synthetic VSMC specific therapeutic target. Store operated calcium entry (SOCE) allows refilling of depleted ER-Ca2+ stores in non-excited cells, including in synthetic VSMCs, and supports migration and proliferation of synthetic VSMCs. Herein, we identify a critical role for PDE1C in regulating the polarization of synthetic human arterial VSMCs (HASMCs) required for their migration and show how this PDE acts as a nexus allowing reciprocal regulation of the SOCE- and cAMP-signaling systems in these cells. Thus, we show that PDE1C localizes at lamellipodia formed by polarized/migrating HASMCs and coordinates a series of hyper-localized Ca2+ and cAMP signaling events within these structures which chronically antagonize their formation. Moreover, we show that these events are dependent on localized actions of the SOCE promoting machinery (i.e. Orai1/STIM1), a Ca2+-activated adenylyl cyclase (ADCY8), PKA and the A-kinase anchoring protein (AKAP79). Based on our findings, we suggest that inhibiting the actions of PDE1C may represent a valid novel therapeutic approach to decrease the burden associated with unregulated migration and proliferation of synthetic VSMCs.

abstract: PhD


title: Pre-compensation of nonlinear distortion of a silicon microring modulator in short reach systems

contributor:
Cartledge, John
Chan, Wai-Yip
Electrical and Computer Engineering

subject:
Digital Signal Processing
Nonlinear Distortion
Silicon Microring Modulator
Short Reach System

abstract:
Silicon photonics has attracted significant attention due to its compatibility with CMOS technology and the potential for both discrete and integrated devices. As a critical component in silicon-based communication systems, silicon optical modulators have been widely investigated, including solitary Mach-Zehnder modulators (MZMs), IQ MZMs, and micro-ring modulators (MRMs). Compared with Si-MZM, Si-MRM has smaller chip size, lower power consumption, and enhanced modulation efficiency, and is potentially preferable for short reach transmission systems. This research focuses on the implementation of an MRM in a high-speed short reach communication system.

One issue with Si-MRMs is the nonlinear electrical-to-optical modulation dynamics. This work investigates pre-compensation of this nonlinear distortion by back-calculation. An MRM model is firstly set up using Matlab. Through back-calculation of the model, an electrical drive signal is calculated based on a desired modulator output optical intensity. The back-calculated drive signal has a broad frequency spectrum which would be difficult to generate using a practical digital-to-analog converter (DAC). Truncation of the drive signal bandwidth shows that a DAC sampling rate working at twice the symbol rate produces relatively good results.

The system bit-to-error ratio (BER) performance is investigated with and without fiber transmission for a 28 Gbaud PAM-4 signal. The systematic simulation includes drive signal generation, electrical to optical conversion by the MRM model, fiber transmission, optical to electrical conversion and receiver side digital signal processing. Since the pre-compensation technique only deals with the distortion in modulation, fiber dispersion during transmission becomes the main factor affecting the system BER performance. Thus a linear decision-directed least mean square (DD-LMS) equalizer and a Volterra nonlinear equalizer are implemented at the receiver to equalize the signal distortion induced by fiber dispersion. In order to verify the simulation results, experiment has been performed using an un-packaged MRM chip. The chip exhibits bit error free transmission for 28 Gb/s on-off keying (OOK) modulation, but signal distortion is induced during the modulation, which produces poor results for PAM-4 signal modulation. Thus a direct comparison between simulation and experimental results was not possible.

abstract: M.A.Sc.


title: Rhodium-Catalyzed Allylic Alkylation of Enolates and Homoenolates: Enantioselective Construction of α- and β-Stereogenic Carbonyl Compounds

contributor:
Evans, P. Andrew
Chemistry

subject:
Organic Chemistry
Catalysis
Rhodium
Enolate Alkylation

abstract:
The asymmetric alkylation of enolates is a particularly versatile method for the construction of -stereogenic carbonyl motifs, which are ubiquitous in synthetic chemistry.  Over the past several decades, the focus has shifted to the development of new catalytic methods that depart from classical stoichiometric stereoinduction strategies (eg. chiral auxiliary).  In this way, the enantioselective alkylation of prochiral enolates greatly improves the step- and redox-economy of this process, in addition to enhancing the scope and selectivity of these reactions.  The following thesis outlines some of our efforts in this area, in which we have recently developed an enantioselective rhodium-catalyzed allylic alkylation reaction with unstabilized enolates and related nucleophiles.  The thesis is divided into three chapters, including a comprehensive literature review that highlights the current state-of-the-art methods, followed by two research chapters that detail the development, scope and mechanistic aspects of two novel “enolate” alkylation processes.
Chapter 1 commences with a brief introduction to enolate alkylation, which is followed by a detailed analysis of the historical development and modern approaches for catalytic enantioselective enolate alkylation.  The review is divided into two major subsections; namely, the reactions of cyclic and acyclic enolates will be treated separately, thus delineating the significant achievements in each area.
Chapter 2 highlights our development of the enantioselective rhodium-catalyzed allylic alkylation of prochiral aldehyde enolates.  This chapter opens with a summary of the related organocatalytic methods that employ enamine nucleophiles to construct α-stereogenic aldehydes.  In this regard, the limitations with these methods set the stage for the development an alternative approach involving unstabilized aldehyde enolates.  Hence, we have utilized an enantioselective rhodium-catalyzed allylic alkylation reaction to enable the construction of acyclic quaternary stereogenic centers from α-aryl aldehyde pronucleophiles.
Chapter 3 illustrates the enantioselective rhodium-catalyzed allylic alkylation of a homoenolate nucleophile.  After a brief introduction on homoenolate alkylation; namely, the use of heteroatom-stabilized allylic anions as synthetic homoenolate equivalents, our development of a catalytic enantioselective variant of this process is discussed.  To this end, we have shown that lithiated unsaturated α-amino nitriles deliver β-stereogenic carbonyls via regioselective allylic alkylation followed by in situ hydrolysis of the cyanoenamine intermediates.

abstract: PhD


title: Engagement of Children, Families, and Care Providers in the Selection or Development of Patient Reported Outcomes

contributor:
Fayed, Nora
Rehabilitation Science

subject: Review Measurement Prom Prem

abstract: BACKGROUND: The growing prevalence of chronic conditions in childhood calls for a child and family engaged approach to research. Engaging with children and families across the selection of outcomes and development of measures may be a promising way to optimize the impact of research that evaluates interventions by measuring what matters to these populations. The extent to which children and families have been engaged in outcome selection and development is unknown. OBJECTIVES: 1) identify the extent to which children and families are currently engaged in the selection of outcomes and development of measures and, 2) elicit the preferences of caregivers and complex care providers of children with medical complexity pertaining to the development of feeding and medical technology experience measures. METHODS: Manuscript 1. A systematic review assessed the extent to which children or families were involved in the selection or development of child-specific outcomes and measures using the IAP2 Spectrum of Public Participation. Manuscript 2. A cross-sectional survey design rated preferences for measurement development between stakeholder (parent versus service provider) groups using Mann-Whitney U and Chi-Square statistical tests. RESULTS: Manuscript 1. Seven studies focused on the selection of outcomes and 29 studies pertained to measure development; child or family engagement in outcomes research was focused at the ‘Involve’ level of the IAP2. Manuscript 2. A total of 39 caregivers and 33 complex care providers of CMC who completed the survey demonstrated non-significant differences in preference with the exception of measure length and transparency preferences. Both groups identified that measure results should be responsive to change instead of producing norm-referenced results. Caregivers expressed further preference to complete measures remotely (e.g. on smartphones) in lieu of during clinical appointments. CONCLUSIONS: Engaging children and families as equals in outcome selection and development is an unexplored area of research. Furthermore, eliciting family preferences is a feasible way to make decisions in the development of a measure.

abstract: M.Sc.


title: Provenance, mineralogy, geochemistry, geochronology and Pb isotope systematics of meta-siliciclastic rocks in the Mesoproterozoic Upper Vazante Sequence, Brazil: Implications for metal sources and base metal metallogeny

contributor: Geological Sciences and Geological Engineering

rights: Attribution-NonCommercial 3.0 United States

subject:
Geology
Geochemistry
Zinc
Metallogeny
Lead
Radiogenic isotopes

abstract:
The objective of this research is to investigate the origin and evolution of meta-siliciclastic rocks within the Mesoproterozoic Upper Vazante Sequence (1300 to 1100 Ma) in order to improve understanding of metal sources and metal mobility in the Vazante – Paracatu zinc mining district, Brazil. This was achieved through integrated study of the mineralogy, geochemistry, detrital zircon geochronology and whole-rock lead isotope compositions of meta-siliciclastic rocks occurring below and within carbonate strata that host pre-orogenic (1200 to 1000 Ma) and syn-orogenic (850 to 650 Ma) Zn – Pb silicate and sulfide orebodies.
Lithogeochemistry of meta-siliciclastic rocks from the Serra do Garrote Formation (below carbonate rocks) and Serra do Poço Verde Formation (interbedded with carbonate rocks) indicates sediments were derived from andesitic to felsic, continental arc-related rocks. Detrital zircon U – Pb dates and provenance patterns suggest major sources of detrital material were Paleoproterozoic arc rocks, related to the Trans-Amazonian orogeny that built the Columbia Supercontinent (2.20 to 1.90 Ga). Deposition of these meta-siliciclastic rocks occurred between 1.30 and 1.20 Ga, during or after continental rifting related to continental breakup.
Carbonaceous phyllites and phyllites from the Serra do Garrote Formation are enriched with respect to Zn and associated elements (e.g. Cd, Hg, In, Cu, V, U). Zn-enrichment is related to pre-orogenic hydrothermal sulfides that formed between 1200 and 665 Ma. Lithogeochemistry and whole-rock Pb isotope compositions of Zn-enriched phyllites suggest that metals were derived from upper crustal material and transported by U-bearing fluids.
The lithogeochemical and Pb isotope signatures of siliciclastic-hosted mineralization, occurring underneath mineralized and un-mineralized carbonate strata, are similar to those from syn-orogenic carbonate-hosted Zn deposits. Although there is textural evidence that pre-orogenic sulfide mineralization was locally remobilized during the Brasiliano Orogeny, there is little evidence that measurable quantities of Zn were removed from the Serra do Garrote Formation during its evolution. The similar geochemical and isotopic signatures in the carbonate-hosted syn-orogenic orebodies and the Serra do Garrote pre-orogenic mineralization suggest that metals were derived from similar sources, such as the underlying basement that siliciclastic detritus originated from and upon which, the Upper Vazante Sequence was deposited.

abstract: PhD


title: Towards a sustainable Arctic fishery: Population genomics of lake whitefish in a hybrid species complex

contributor:
Lougheed, Stephen
Biology

subject:
Population Genetics
Genomics
Hybridization
Genetic Structure
Conservation
Fisheries Management
Lake Whitefish
Arctic Cisco
Sardine Cisco
Coregonus Clupeaformis
ddRADseq
Sustainable Fishery

abstract: Genetic variation is an important predictor of population persistence under changing or stressful environmental conditions. Consequently, efforts to preserve genetic variation by identifying genetically distinct populations and delineating management units are primary goals of conservation genetics and fisheries management. Accelerated melting of sea ice in the lower Northwest Passage (LNWP) in Nunavut has recently opened the passage to shipping, providing an opportunity for fishery establishment. Nunavut communities have some of the highest rates of food insecurity across Canada, so the commercial harvest of profitable fish species could help to alleviate this crisis. However, sustainable fishery management in the LNWP requires the characterization of genetic structure in focal species to determine the best practices for managing demographically independent populations and, over the longer term, conserving genetic variation. The lake whitefish (Coregonus clupeaformis) is an important commercial species across Canada, is abundant in the LNWP, and is valued by the local people in Nunavut. However, lake whitefish have only recently expanded their range into this area, and the distribution of their genetic variation across the LNWP is unknown. Using genome-wide panels of single nucleotide polymorphisms, my results suggest one genetic population of lake whitefish in the LNWP. However, using putatively adaptive markers, I find weak evidence for two to three units of lake whitefish in the area. Further, I uncover genetic indication of hybridization between lake whitefish, Arctic cisco (C. autumnalis), and sardine cisco (C. sardinella) in the LNWP. Admixture among these species may make setting sustainable catch limits for lake whitefish challenging, as fishing pressures will likely decrease the abundance and genetic diversity of each species. Thus, my work aims to inform fishing regulations that reduce the relative exploitation of genetically distinct units of lake whitefish and minimize impacts of harvest on hybrids and their parental species. Setting reasonable fishing limits and preserving the genetic diversity of lake whitefish in the LNWP will reduce the likelihood of a fishery collapse, and increase probability for the species to become a sustainable resource for the people of Nunavut.

abstract: M.Sc.


title: Modelling Methane Emissions from Arctic Lakes

contributor:
Boegman, Leon
Civil Engineering

subject: methane arctic emissions

abstract:
Climate change in the Arctic is moving at a greater rate than the rest of the world, and the urgency of characterizing greenhouse gas emissions from water bodies located in high latitudes has become a subject of intensive research during the last two decades. Methane (CH4) emissions from freshwater systems are believed to be the most important source of uncertainty in the global greenhouse gas budget, and their positive feedback has been excluded from earth systems models. This powerful gaseous fuel can be emitted to the atmosphere via diffusion or ebullition, with fieldwork suggesting the latter is the primary mode of release.
	Previous process-based models have been developed in the past to determine these emissions; however, they often require several inputs and lakes characteristics that are not readily available. Bearing these limitations in mind, this study quantifies ebullition during the ice-free season from four kettle oligotrophic lakes located in Arctic Alaska. By using a one-dimensional bulk mixed-layer thermodynamic lake model, temperature profiles were obtained, and a CH4 subroutine was also included to determine ebullition and diffusion fluxes as well as CH4 concentrations in the water column. Following model validation, meteorological data from a general circulation model was then implemented to predict future CH4 sediment emissions and their resulting atmospheric fluxes.
	Results were validated against published observed data from the literature; the model calculated the temperature profile of the lakes with root mean square errors of <4°C. Accordingly, CH4 water concentrations were modelled with root mean square errors of <<1µM, in both deep and shallow systems. Ebullition fluxes showed a high interannual variability which further validated previous evidence of the high heterogeneity of this process. Results of increases in atmospheric fluxes were significant; under three Representative Concentration Pathways, emissions from all systems are expected to increase at least 21% over the next 80 years. This study presents a simple formulation with limited constraints to estimate emissions via ebullition; it is expected that this model will be embedded into land surface schemes of global and regional climate models to predict emissions from the Arctic and potentially from the rest of the globe.

abstract: M.A.Sc.


title: Effect of Terminal Electron Acceptors on Greenhouse Gas Emissions in Oil Sands Tailings

contributor:
Ramsay, Juliana
Chemical Engineering

subject: Sulfate, Nitrate, Phosphate, Ammonium, Methane, Carbon dioxide, Oil Sands Tailings

abstract:
Surface mining of Alberta's oil sands produces large volumes of water and solid wastes stored in oil sands tailings ponds. Tailings ponds contain numerous contaminants that have negative effects on the environment (air, water, and land). Each tailings pond has its unique characteristics depending on different chemical additive used during bitumen extraction. Diverse microbial populations developed within each pond which have a vital role in the bioremediation of toxic compounds therein. As tailings ponds age and at low redox conditions (~ -250 mV), some prokaryotes, particularly methanogenic archaea, oxidize petroleum hydrocarbons (such as naphtha) using acetic acid or CO2 as a terminal electron acceptor (TEA) resulted in methane (greenhouse gas) efflux from OSTPs. Some studies estimated the current methane emissions to be up to 43 million liters/day. GHG evolution is stimulated by the naphtha diluent that ends up in tailings ponds during the bitumen extraction process but the processes controlling methane production are not well understood.
In this study, the effect of TEA (SO42- and NO3-), nutrients (PO43- and NH4+), and carbon source (naphtha) on GHG production was investigated in microcosm experiments using mature fine tailings of Suncor Energy Pond 7. In NO3- and SO4-amended microcosms, methanogenesis was reduced by 98.5 and 97.8%, respectively, as initial NO3- or SO42- concentration increased. In MFT-amended with phosphate under methanogenic conditions, CH4 production increased with increasing PO43- concentration by a factor 2.4 times that of the unamended biotic control. Biogenic gas production (CH4, H2S, and N2O) increased with increasing naphtha concentration. The yield of CH4 produced from naphtha consumed under methanogenic conditions was 0.058 g/g which is lower than the theoretical yield since some of the carbon from naphtha was likely used to make microbial biomass and/or the formation of biogenic CO2 or other intermediates like acetate. There was a difficulty in measuring the biogenic CO2 produced due to the equilibrium between HCO3− and CO32− in MFT and biogenic CO2. In conclusion, it is possible to minimize GHG emissions by manipulation of TEA. However, increasing naphtha and/or phosphate concentration will result in increasing CH4 production.

abstract: M.A.Sc.


title: The Racial Mosaic: Race, Cultural Pluralism, and Canadian Multiculturalism

contributor:
Walker, Barrington
History

subject:
Multiculturalism
Cultural Pluralism
Race
Racism
Scientific Racism
Whiteness
Watson Kirkconnell
Robert England
John Murray Gibbon

abstract: This dissertation examines the intellectual origins of the Canadian federal government’s official policy of multiculturalism. The first half employs the methodology of historical biography and examines the life and thought of three Canadian public intellectuals: T. Watson Kirkconnell, Robert England, and John Murray Gibbon. While each of these men developed philosophies of cultural pluralism in the context of larger projects, all three philosophies were rooted in colonialism, relied on the idea of race as a biological reality, focused on European groups, and excluded (and often denigrated) those racialized as non-white. These three men were recognized by the State and civil society as experts on racial diversity, and in the late interwar period they were called upon by governmental agencies such as the Canadian Broadcasting Corporation. The programs they designed, which were aimed at fostering national unity, were also limited by whiteness. During the Second World War, the lines between State and civil society blurred as the promotion of “racial” or cultural diversity became an increasingly official endeavour. The State utilized these public intellectuals to help shape official approaches to “racial” unity but again these efforts focused only on Canadians of European descent. The second half of the dissertation examines shifting notions of race in the postwar period and details how these ideas continued to shape discussions about diversity and citizenship. It unpacks the debates over changing immigration policy, citizenship, and finally the Royal Commission on Bilingualism and Biculturalism. The final chapter examines the shift from ad-hoc cultural pluralism to an official policy of multiculturalism. It demonstrates that this policy was focused on Canadians of non- British, non-French, European descent, with an emphasis on their folk cultures. The dissertation therefore concludes that the original policy of multiculturalism is best understood not as a break with but rather as a manifestation of white normativity in Canada.

abstract: PhD


title: Ethnic Projects & Ethnic Boundary-Making: The Agency of Re/Ethnicized Youth in Post- genocide Bosnia-Herzegovina & Rwanda

contributor:
Csergö, Zsuzsa
Haklai, Oded
Political Studies

subject:
Ethnicity
Ethnic Conflict
Genocide
Reconciliation
Rwanda
Bosnia-Herzegovina
Youth
Agency

abstract: PhD


title: O antigen biosynthesis in Gram-negative bacteria: Characterization of alpha1,4-glucosyltransferase WclY from Escherichia coli O117 and development of glycosyltransferase inhibitors.

contributor:
Brockhausen, Inka
Biomedical and Molecular Sciences

subject: Master's Thesis

abstract: Gram-negative bacteria have a polysaccharide coat (O antigen) consisting of repeating units of oligosaccharides that is assembled by glycosyltransferases. Many of these bacteria are associated with disease, and the polysaccharides are functionally important for immune responses. In light of increasing antibiotic resistance it is critical to develop new antibacterial strategies and gain knowledge of the mechanisms by which bacteria assemble their virulence factors. We hypothesize that inhibition of the glycosyltransferases responsible for O antigen synthesis in pathogenic Gram-negative bacteria can lead to the attenuation of bacteria’s virulence. The O antigens in O117 and O107 serotypes of Escherichia coli, differ by a single sugar residue. The glucose (Glc) residue found in the O antigen of E. coli O117 [D-GalNAcβ1-3-L-Rhaα1-4-D-Glcα1-4-D-Galβ1-3-D-GalNAc]n is replaced by N-acetylglucosamine (GlcNAc) in the O antigen of E. coli O107 (GalNAc is N-acetylgalactosamine, Rha is Rhamnose, Gal is galactose). The glycosyltransferases that create the Glc/GlcNAcα1-4Gal linkage are WclY(O117) and WclY(O107), and differ in only 3 amino acid residues. We have expressed WclY(O117) in a soluble and active form in the Lemo21 (DE3) expression system. We developed an activity assay for Glc-transferase WclY using a synthetic analog of its natural acceptor substrate and subsequently characterized the enzyme. WclY(O117) is a retaining Glc-transferase (sugar of the donor substrate retains α/β stereochemistry post-transfer) of the Carbohydrate Active Enzymes (CAZy) GT4 family; it has a strict substrate specificity requiring Galβ1-3GalNAcα-diphosphate lipid as the acceptor. In contrast, the donor substrate specificity is more relaxed. The structures of reaction products were confirmed using Electrospray Ionization-Negative ion mode Mass Spectrometry as well as Nuclear Magnetic Resonance Spectroscopy. Mutants were expressed to provide insight into the catalytic mechanism of WclY. Mutants transferred sugars from UDP-Glc, UDP-GlcNAc, UDP-Gal or UDP-GalNAc at varying levels. By mutating Arg194 we were able to convert the Glc-transferase to a GlcNAc-transferase. Protein modeling confirmed the role of Arg194 and other amino acids in the catalytic activity of WclY. Characterization of the enzyme has opened the door for testing of compounds with the potential to act as antimicrobial and antiseptic agents.

abstract: M.Sc.


title: Evaluation of Laser-Drilled Holes Used for Effusion Cooling

contributor:
Birk, A. Michael
Mechanical and Materials Engineering

subject:
Effusion Cooling,
Laser-Drilled Hole
Cooling Effectiveness

abstract: PhD


title: Microstructural Characterization of 3D Deposited Metal Structures

contributor:
Daymond, Mark
Mechanical and Materials Engineering

subject:
Materials Science
Electrodeposition
Additive Manufacturing
Selective Laser Melting
316L Stainless Steel
Transmission Electron Microscopy
Scanning Electron Microscopy
Transmission Kikuchi Diffraction
Electron Backscatter Diffraction
Nickel
Crystallography
Crystallographic Texture
Materials Characterization
Microstructure

abstract:
The microstructure of deposited materials is characterized using a variety of techniques. The two specific types of deposited materials studied are electrodeposited nickel and additive manufactured stainless steel. A focus is on utilizing optimal cross-sectional characterization techniques to observe the microstructure, where optimal refers to the length scale being probed and the cost of preparation and characterization methods. Techniques ranging from optical transmission electron microscopy are used. Three different length scales of electrodeposited nickel are observed, and a set of 16 SLM processed 316L stainless steel weld tracks are observed.

The largest length scale nickel material is a commercially available foam, likely produced by electroplating nickel onto a sacrificial polymer template. The foam was prepared for EBSD using modification to standard metallography techniques. The average grain size was 5.73 µm with a random texture, suggesting a heat treatment used to remove the polymer template.

Secondly, we studied mesoporous nickel samples. A measure of particle size as well as deposition layer thickness was performed using ImageJ in conjunction with SEM imaging.

The smallest microstructural length scale of nickel materials was a set of nanostructured electrode catalysts. The grain size seen in the deposition layers was in the hundreds of nanometers, and an overall growth texture in the {112} direction was observed.

The 316L stainless steel weld tracks were polished using standard metallographic techniques and etched in oxalic acid. This revealed a cellular structure. The cell sizes of two weld tracks were measured in ImageJ and compared with their applied energy densities. It was found that the track with the lower energy density had a slightly smaller cell size, the sizes being 4.7 ± 1.5 µm and 6.2 ± 1.2 µm respectively. An EBSD map of one weld track was also taken, illustrating the directional growth of SLM processed grains.

abstract: M.A.Sc.


title: Characterization and Age of North-Verging Back Structures in the Tethyan Sedimentary Sequence, Hidden Valley, Central Nepal Himalaya

subject:
Central Nepal Himalaya
Folds
Tethyan Sedimentary Sequenece
Orogen

abstract:
Throughout the central Nepal Himalaya, the Tethyan sedimentary sequence (TSS) is structurally dominated by a train of north-verging folds, in apparent contradiction to the dominantly south-propagating Himalayan orogen. The absolute age of folding is unknown, although previous structural observations have suggested that folding may predate Miocene movement of the South Tibetan detachment system. Age dating and characterization of this deformation event is critical for determining the timing of coupling and/or decoupling of the upper crust from the mid-crust during the Himalayan orogen, as well as elucidating the early collisional history of the orogen.
Structural mapping in Hidden valley, central Nepal, reveals four phases of deformation (D2, D3, D4 and D5) within anchizonal to epizonal metamorphic grade Ordovician to Jurassic TSS rocks. Megascopically, D2 is defined by large, asymmetric north-verging folds; microscopically, D2 is seen as an axial planar continuous to spaced cleavage. Bed length restoration of F2 folds indicates a minimum of 40% shortening and 180% thickening during D2. Muscovite geochemistry, geochronology and microstructural analyses are used to identify two chemically and structurally distinct generations of muscovite in the TSS, one of which is detrital (Al), and one of which is new growth (A2). Structurally, Al is randomly oriented and intermittently rotated into S2 and S4 cleavage planes, while A2 is parallel to S2 axial-planar cleavage and also occurs as growth rims on Al. Conventional 40Ar/39Ar step heating methods indicate that Proterozoic and Paleozoic detrital Al muscovite Ar systematics have been weakly reset. A2 muscovite, dated by the in situ UV laser 40Ar/39Ar spot-fusion method and assuming closed system since metamorphism, is at least as young as 35.5±1.7 Ma, which is interpreted as a maximum age for F2 folding. The UV laser shows great potential for in situ dating of cleavage domains. D2 north-verging folds are Himalayan in age, likely occurring between ~35 and 22 Ma; this is the first maximum age constraint obtained for this deformation. D2 folds are interpreted to have formed in Eocene-Early Oligocene time, near the maximum age limit of this range (~35 Ma), coeval with kyanite-grade metamorphism in the mid-crust. The north-verging folds, which formed in the upper crust, were then subsequently detached/decoupled during midcrustal southward extrusion at 22-18 Ma.

abstract: M.Sc.


title: Service Performance of a Cured In Place Polymer Pipe Liner for Deteriorated Cast Iron Pressure Pipes

contributor:
Hoult, Neil
Moore, Ian
Civil Engineering

subject:
CIPP
Liners
Pipes
Deterioration
Trenchless Technology

abstract:
Although Cured-In-Place Pipe (CIPP) liners have been used extensively across North America, their in-situ performance in deteriorated pipe conditions has not been extensively studied. The purpose of this research work is to develop a better understanding of the service performance of CIPP liners in cast iron water pressure pipes by experimentally quantifying the hoop and axial strains in the liner when exposed to various loading conditions. In this research, the application of distributed optical fiber sensing to study the mechanical properties of a commercially available structural CIPP liner used for pressure pipe repair was demonstrated.
Using distributed strain sensing, large-scale experimental investigations were conducted to evaluate the mechanical response of a CIPP liner where it spans across localized areas of failure in the host pipe (i.e. perforation and ring fracture) by quantifying the strains in the liner. Axial strain measurements obtained from surface bonded optical fibers support the use of the current ASTM F1216-16 design rules for pressure pipe liners spanning across small sized perforations (up to 50 mm in diameter in a pipe with a 154 mm overall diameter). However, ASTM F1216-16 design recommendations produce unconservative estimates for larger perforations (up to 75 mm diameter in a pipe with a 154 mm diameter). For the case of a liner which spans a pre-existing ring fracture in a host pipe subjected to angular rotation, it was observed that the location of maximum opening in the fracture is the critical location where the liner could experience failure. Results also showed that debonding (i.e. separation between the liner and the host pipe) decreases the maximum strains in a liner and that the extent of debonding is impacted by internal pressure and alignment of the pipe across the fracture. Due to the polymeric nature of the liner, the tensile creep properties of the liner were investigated. Results suggest that the use of an industry-accepted 50% creep retention factor to estimate the 50-year service life of a liner could produce unconservative results.

abstract: PhD


title: Stable isotope analysis reveals the minimal incorporation of petrogenic carbon into a freshwater food web following experimental diluted bitumen spills

contributor:
Orihel, Diane
Environmental Studies

subject:
Oil Spill
Diluted Bitumen
Stable Isotope Analysis
Experimental Lakes Area

abstract: Bitumen mined from the Canadian oil sands is viscous to such a degree that it must be diluted to flow in pipelines resulting in diluted bitumen (dilbit). Dilbit has chemical and physical properties that differ it from conventional crude oils so research into dilbit’s behaviour is needed to inform spill response. Monitored natural attenuation relies on the biodegradation of petroleum by indigenous biota resulting in an assimilation of petrogenic carbon. Researchers inferred this assimilation by measuring stable carbon isotopes (δ13C) at the site of a marine crude oil spill, but this approach has never been applied to dilbit spills into freshwater. We experimentally spilled dilbit into nine 10-m diameter limnocorrals installed into the littoral zone of a boreal lake in northwestern, Ontario, Canada. I hypothesize that if petrogenic carbon is being assimilated, then I will measure a 13C-depletion in exposure organisms because hydrocarbons from crude oil tend to be 13C-depleted compared to most organisms. The δ13C values of phytoplankton increased more in the control limnocorral (5 ‰) than the 180-L dilbit-treated limnocorral (1‰), suggesting that the natural enrichment seen in the control was dampened in the dilbit-treated limnocorrals due to the phytoplankton assimilating 13C-depleted hydrocarbons. Periphyton harvested from dilbit-treated limnocorrals were depleted in 13C relative to the control periphyton. We also measured δ13C of Pyganodon grandis mussels housed for 25 days in aquaria containing water from the limnocorrals. The δ13C value of mussels exposed to oil-contaminated water from the 42-L and 82-L limnocorrals was significantly 13C-depleted compared to the control (p < 0.01), indicating that mussels may be filtering oil components and assimilating petrogenic carbon. The lack of substantial 13C-depletions in the food web suggests that the incorporation of oil carbon and, by extension, rates of biodegradation from the dilbit spills was minimal. Researchers should be cautious when using stable isotopic analysis of carbon as organism’s natural isotopic values are highly variable, the δ13C of study organisms and crude oil can be similar which complicates interpretation, and measurable 13C-depletions occur over extended time frames.

abstract: M.E.S.


title: Design Optimization and Part Reduction of Components in a Monorail Ceiling Structure

contributor:
Kim, Il Yong
Mechanical and Materials Engineering

subject:
Design Optimization
Topology Optimization

abstract:
There is a growing need in transportation industries for design tools and methodologies that can quickly and effectively assist designers in developing designs that are lighter and simple to manufacture. This research outlines a methodology using existing advanced design tools to re-design a series of components in a monorail ceiling structure. The goal of the redesign was to reduce the mass, manufacturing complexity and manufacturing cost to the ceiling structure while maintaining structural performance. For the redesign, structurally critical components in the center web structure were selected for optimization. These components were a cross-beam, and the bracket that attaches the cross-beam to the roof.
	Initial finite element analysis was completed on each component and the entire center web to obtain a baseline performance metric. Optimization was then completed in two stages. First a topology optimization was completed for the entire center web area to assess placement of components. Secondly topology optimization was completed on each of the component of interest. The optimization of the components was completed multiple times with alterations to the design space and objective function optimization to yield improved results. This process yielded two potential designs for each component.
From the results in the optimization stage, re-designed components were created for both the secondary and tertiary topology optimized component designs. Using these re-designed components, an updated center web was created based off these designs and the initial optimization. Finite element analysis was completed on the updated components and the updated center web. These results were compared to the original finite element analysis results. From this result, the updated components and center web were found to be lighter and were easier to manufacture than the original designs, while meeting performance criteria. In the center web structure, the number of components was reduced by 30%, and the mass was reduced by 43%.

abstract: M.A.Sc.


title: Manufacturing Constraints for Topology Optimization: A Particle Diffusion Based Methodology

subject:
Topology Optimization
Design Optimization
Manufacturing Constraints

abstract:
With the need for improved performance becoming more apparent in the engineering workplace, numerical tools like design optimization and topology optimization have been turned to in order to generate new unconventional design concepts. Leveraging concepts from traditional design optimization, topology optimization is a generalized tool suitable for many different applications. However, a challenge posed by topology optimization has been the determination of feasible results from a manufacturing perspective. Manufacturing constraints for topology optimization have been developed over the years in order to guide the optimization problem to a result that is feasible for manufacturing. Many methods have been proposed and have shown that topology optimization results can be developed with specific manufacturing considerations in mind.
This work presents a new manufacturing constraint methodology for topology optimization which utilizes a particle diffusion method to mathematically model and eliminate non-desirable geometric features in the topology optimization procedure. Here, the geometric feature modeling and elimination vary based on the given manufacturing process. The chosen manufacturing constraints studied in this work are single plane casting, split plane casting, 3-axis milling, 5-axis milling, and turning.
The particle diffusion problem leverages the finite element discretization of the topology optimization problem for setup but does not require a finite element solution to the problem. Through the mathematical relationship developed with particle diffusion times and not requiring a finite element solution, particle diffusion for manufacturing constraints overcomes some of the shortcomings of other methods in the existing literature. The entire methodology is formulated in a differentiable manner where design sensitivity calculations can be taken and used in a gradient based optimization scheme. In five numerical examples these manufacturing constraints utilizing particle diffusion are shown. For all examples, manufacturing feasibility for the chosen manufacturing process was achieved at the cost of increased structural compliance.

abstract: M.A.Sc.


title: Modeling the Effect of Scan Path of Thermal Gradients during Selective Laser Melting via Finite Element Analysis

contributor:
Kim, Il Yong
Zak, Gennady
Mechanical and Materials Engineering

subject:
Additive Manufacturing
Selective Laser Melting
Scan Path
Residual Stress
Finite Element Analysis

abstract:
As industry competition and increasingly stringent safety concerns drive the need for increased part performance and decreased part weight, additive manufacturing methods are being turned to as an innovative fabrication method able to produce more complex parts. Despite significant advances in technology since the inception of additive manufacturing in 1980, high thermal gradients during part manufacture can generate residual stresses, part deformation, and even part failure due to cracking. Among other factors such as laser power and speed, scan path directly affects the thermal gradients during manufacturing.
	The work in this thesis compares the thermal gradients generated by nine different scanning methods; six of which have been tested and discussed in previous literature, and three of which are new paths proposed for the first time in this document. A finite element model was created and validated in order to easily test all nine paths, while keeping machine parameters such as hatch distance and laser power constant for all tests. This model can change machine parameters and scan paths easily, and has the ability to change scan paths between layers. The tests found that scan paths that subsection powder layers into smaller areas before scanning produce lower thermal gradients than those that scan the full layer without sectioning. One of the new scan path concepts, deemed the “subsectioned spiral method”, produced the most favourable results most consistently when compared to the other eight paths, and shows signs of being an effective scan path that could outperform the other methods used widely today.

abstract: M.A.Sc.


title: An Overview of the Troilus Au-Cu Deposit, Frotet-Evans Greenstone Belt, Opatica Subprovince, Quebec

subject: Troilus deposit, Frotet-Evans greenstone belt

abstract: A non-research thesis submitted to the Department of Geological Sciences and Geological Engineering in conformity with the requirements for the degree of Master of Science.

abstract:
The Troilus Au-Cu deposit is a low-grade, high-tonnage deposit, located in the eastern part of the Archean Frotet-Evans greenstone belt, in the Opatica Subprovince, Superior Province, Quebec. Total past production and current combined indicated and inferred resources were estimated over 6.4 Moz of contained gold (or 200 t Au, in approximately 230 Mt of ore grading 0.87 g/t Au, Troilus Gold Corp., 2019).

The deposit comprises two main orebodies, the 87- and the J-zones. Both are hosted in ca. 2791 Ma calc-alkaline intrusive rocks, consisting of a metadioritic stock, an amphibolitic unit, and a magmatic or magmatic-hydrothermal breccia. These rocks are crosscut by ca. 2782 Ma felsic dikes. The calc-alkaline suite was emplaced into the volcano-sedimentary sequence of the Troilus Group.

The Troilus deposit is hosted in a zone of intense deformation and experienced upper-greenschist to lower-amphibolite metamorphic conditions. The orebodies in the Troilus deposit display an anastomosed pattern, being parallel to subparallel to a penetrative NE-trending foliation, moderately to steeply-dipping to NW.

The amphibolite, the brecciated unit, and the felsic dikes represent the main host rocks for the mineralization, which has been broadly divided in two distinct types: (i) Au-Cu in fine-grained chalcopyrite-pyrrhotite-pyrite disseminations and stringers parallel to the foliation, representing the dominant ore in the Troilus deposit. It occurs in association with a strong biotitic alteration zone, and it is restricted to the amphibolite and to the matrix of the breccia, in a corridor zone between two main felsic dikes; and (ii) Au-bearing quartz-veins and veinlets in association with sericitic alteration and silicification in secondary high-strain zones, occurring in amphibolite, breccia and felsic dikes.

The Troilus Au-Cu deposit has been interpreted to be formed similarly to porphyry Au-Cu deposits, based on the disseminated style of the mineralization in association with a zoned hydrothermal alteration assemblage, the presence of multi-stage felsic porphyry intrusions and an in-situ hydrothermal breccia. Some studies have suggested a multi-stage structurally controlled “orogenic” gold type model, based on the recognition of two styles of mineralization and their restriction to superimposed distinct and unrelated structures. However, the difficulties imposed by the intense deformation that occurred in the deposit region, associated with a lack of robust structural, geochemical, petrological, and mineralogical data from the deposit- to district-scale have resulted in a limited understanding of the ore system at Troilus.

This report presents a literature review, summarizes and discusses relevant points and controversies regarding the previous studies, while addressing future recommendations to achieve a better understanding of ore genesis at the Troilus Au-Cu deposit.


title: The Design and Integration of an In-Situ Proton Irradiation Tensile Rig

subject:
Proton Irradiation
In-Situ
Nuclear Materials

abstract:
One of the biggest challenges faced in the nuclear industry is understanding and accurately predicting the complex environment found in a nuclear power reactor and its impact on core components and materials. The extreme environment inside a reactor core provides challenges to component design and operation as the large amounts of radiation experienced by reactor components begins to fundamentally change the otherwise well understood material properties. At the Reactor Material Testing Laboratory (RMTL) at Queen’s University, a high energy proton accelerator is used to simulate the neutron damage found in a nuclear reactor and conduct experiments to develop a mechanistic understanding of irradiated material samples and their changing material properties.
This Thesis details the design and integration of an in-situ proton irradiation tensile rig (PITR) at the RMTL facility. The purpose of this apparatus is to provide the means of systematically exploring degradation phenomenon of reactor materials in controlled single variable experiments.
The results from these studies will lead to an improved understanding of irradiation behavior of materials and ultimately help lead to the development of improved safety and efficiency for current and future reactors.
After evaluating the reliability and accuracy of each individual system and component of the PITR, a proof of concept experiment was conducted to demonstrate its capability of conducting an in-situ proton irradiation tensile test. A 75 µm thick pure zirconium foil was irradiated at a damage rate of 1.37 × 10-7 dpa/s, a constant temperature of 350 °C, and a constant applied stress of 30 MPa. The resulting strain rate was compared against that of an identical sample held at the same temperature and applied stress without the applied proton beam. The sample subjected to proton irradiation was found to have a much higher strain rate for the given parameters than the non-irradiated sample.

abstract: M.A.Sc.


title: The Effects of Adhesive Quantity on Out-of-Plane Behaviour in Aluminum Honeycomb Panels

contributor:
Kim, Il Yong
Mechefske, Christopher
Wowk, Diane
Mechanical and Materials Engineering

subject:
Honeycomb Panel
Finite Element Analysis
Experimental Testing
Material Model
Buckling
Crushing

abstract:
Aluminum hexagonal honeycomb panels are commonly used in the aerospace industry to reduce weight due to their high stiffness to mass ratio. The panels are commonly involved in incidents where they are dented in the out-of-plane direction which causes plastic deformation in the face-sheet and buckling collapse of the thin repeating cell-walls in the core. This thesis investigates the responses to barely-visible-impact-damage (BVID) in aluminum honeycomb sandwich panels in the out-of-plane direction with particular attention to the structural adhesive. The structural adhesive forms a fillet shape between the face-sheet and the aluminum core during the 120oC curing process and can coat over 50% of the honeycomb core thickness in some cases. Because BVID is common in honeycomb panels, this study looks to improve the understanding of how various factors affect the panel’s response to denting, starting with the adhesive at the interface between the face-sheets and core.
To simplify the problem, the out-of-plane direction was isolated by compressing a panel uniformly. This provided results showing how the adhesive geometry affects the stiffness in a key loading direction with respect to denting. The adhesive was found to cause a higher critical buckling stress and a lower percent compaction before densification. Buckling location was more random when compared to the honeycomb core with no adhesive due to fixed constraints at the top and bottom of the core, where damage would usually initiate. A new mathematical prediction of the stress-strain response was developed, which will be referenced as a material model, to account for adhesive effects. The proposed mathematical material model for the stress-strain curve resulted in R-squared values above 0.82 when compared to experimental data.
Force-displacement data collected from quasi-static experiments with a spherical contact showed that the amount of adhesive was positively correlated to the damage resistance, energy absorbed and the depth of interior buckling damage in the core. This study provides researchers and engineers with experimental results that present a relationship between the structural adhesive and the response to BVID in honeycomb panels.

abstract: M.Sc.


title: Animal Personhood: A Postanthropocentric Multispecies Legal Subjectivity

contributor:
Kymlicka, Will
Philosophy

rights: Attribution-NonCommercial-NoDerivs 3.0 United States

subject:
Legal Subjectivity
Legal Reform
Animal Law

abstract: This thesis looks at the human relationship to other animals in the eyes of the law. Many contemporary legal systems categorize nonhuman animals as property, which means that they can be objectified and commodified. The property status has been widely criticized for its inability to provide the most vulnerable among us with protection from human violence and exploitation. Animal law scholars have thoroughly documented the failures of welfarist reform, and call for the recognition of nonhuman animals as legal subjects and rightsholders via legal personhood as a requirement of justice. In this thesis, I turn to Maneesha Deckha’s postcolonial feminist critique of personhood as an exclusionary and anthropocentric legal subjectivity that settler colonial legal systems have inherited. In response, I argue that we should redefine personhood in animal terms for the sake of those who are marginalized and oppressed. I propose “animal personhood” as a human and nonhuman legal subjectivity that is grounded in equality as well as the embodied and relational dimensions of our vulnerability as sentient beings. Animal personhood is meant to legally affirm the moral and political rights of animal persons.

abstract: M.A.


title: An examination of prosodic awareness and reading achievement across Grades 3 to 6: A focus on English Monolinguals and Chinese-English Bilingual Children

contributor:
Christou, Theodore
Wade-Woolley, Lesly
Education

subject:
Prosodic Awareness
MorphologicalAawareness
Word Reading
Reading Comprehension

abstract:
This dissertation comprises two studies that examine predictors of children’s reading. In Study 1, I investigated the unique contributions of prosodic awareness and morphological awareness to word reading and reading comprehension in English-only children (n=110) across Grades 4 and 5. Prosodic awareness and morphological awareness were unique predictors of word reading, and morphological awareness was the only predictor of word reading that also explained individual differences in reading comprehension. The relationship between prosodic awareness and word reading was partially mediated by phonemic awareness and morphological awareness, and the relationship between prosodic awareness and reading comprehension was fully mediated by morphological awareness and word reading. In Study 2, I examined prosodic awareness and morphological awareness among a comprehensive set of predictors in English-only (n=90) and Chinese-English bilingual (n=128) children between Grades 3 to 6. I provide evidence illustrating that prosody represents a separate dimension of phonology. Prosody explained unique variance in word reading after accounting for segmental phonological awareness in both language groups, but these effects did not remain after accounting for morphological awareness and orthographic awareness in the model. The path analyses revealed indirect effects of prosody on word reading through morphological awareness in the English-only group, and indirect effects of prosody on word reading through morphological awareness and segmental phonology in the Chinese-English bilingual group. To conclude, prosody was a contributor to word reading processes, and morphology had unique effects on word reading and reading comprehension processes.

Prosody represents a broad construct, which I have focused my examination on word-level prosodic awareness in relation to reading outcomes. Across the three samples of children across Grades 3 to 6, prosody was a significant correlate with reading outcomes and established predictors including vocabulary, segmental phonological awareness, and morphological awareness. I extended this investigation of prosody to a second language group and provided insight into the relative contributions of these predictors within a comprehensive and complex model of word reading. To conclude, prosody may play a supportive role in the reading network, but it is a distinct construct that should be considered seriously in theoretical models of reading.

abstract: PhD


title: Reason, Agency, and the Malaise of Mental Health

contributor:
Bakhurst, David
Philosophy

rights: Attribution-ShareAlike 3.0 United States

subject:
Epistemology
Psychiatry
Agency
Jonathan Dancy
Hanna Pickard
Mental Health
Depression
John McDowell
David Bakhurst
Reason
Psychology

abstract: Mental health conditions create incredibly complex experiences in the world. Some medical professionals argue that mental health conditions are purely physical phenomena – simply a deficiency of brain chemicals. Some philosophers construe reason (and therefore the limits of philosophy) too narrowly to say anything interesting about mental health conditions. I aim to develop a complex account of rational agency that explains how we navigate the world in general, and mental health conditions in particular. I then develop examples to show how this account of agency can help explain what it is like to live with a mental health condition. My account aspires to shed light on the nature of agency and provide some much-needed theoretical backing for psychological methods of treating mental health conditions.

abstract: M.A.


title: Localized prostate cancer patients' preferences for hypofractionated radiotherapy: A discrete choice experiment

contributor:
Brundage, Michael
Richardson, Harriet
Public Health Sciences

subject:
Discrete Choice Experiment
Prostate Cancer
Patient Preference
Hypofractionated Radiotherapy

abstract:
Introduction: While external beam radiotherapy (EBRT) has always been a standard of care for localized prostate cancer patients, hypofractionated EBRT has now become a standard EBRT approach. We aimed to elicit the relative weight patients place on various aspects of EBRT and to compare these findings to clinical trials results, with a goal of informing clinical practice.

Methods: A discrete choice experiment was designed in which men had to choose between two EBRT profiles that differed in five treatment attributes: effectiveness, acute toxicity, late toxicity, length, and fiducial marker implantation. We recruited prostate cancer patients with localized disease who had completed or were undergoing EBRT at our institution. Conditional (multinomial) logit regression (MNL), mixed multinomial logit (MXL), and latent class (LC) models were used to analyze the relative importance of treatment attributes, and the trade-offs this patient population were willing to make between attributes. These results were compared to explicit ranking and rating scores the participants completed for internal validation, as well as to clinical trials findings for interpretation. The MXL and LC models were used to compare realistic EBRT scenarios that corresponded to conventional fractionation, moderate hypofractionation, and stereotactic body radiotherapy, and determine what characteristics resulted in individuals preferring certain scenarios.

Results: All treatment attributes’ parameter estimates were significantly different from zero, and across the MNL and MXL models the most important attributes were risks of PSA recurrence and late toxicity. The rating exercises agreed with the quantitative results. Preference heterogeneity was present, largely due to age and distance patients traveled to the cancer centre. One latent class (the “convenience group”) were not willing to lengthen EBRT to reduce risk of toxicity at any level within the model.

Conclusions: Prostate cancer patients with localized disease place importance on convenience of EBRT. Older participants tend to be willing to accept a risk of increased toxicity to be treated with hypofractionated regimens. This risk is well within the expected risk based on clinical trial results. Participants had a good understanding of the DCE, and the responses were internally valid.

abstract: M.Sc.


title: Relational Leadership: Exploring the Doctoral Supervisor–Student Context in Higher Education in Canada

contributor:
Kutsyuruba, Benjamin
Education

subject:
Relational Leadership
Positive Leadership
Doctoral Supervision
Mentorship/Coaching
Higher Education

abstract:
Review of research literature revealed that doctoral students’ well-being and performance are influenced by the leadership style their supervisors exhibit. The purpose of this research was to explore the nature of relational leadership and the leadership competencies that influence the supervisor–doctoral student relationship within the Canadian university context. I conducted an interpretive phenomenological study and I interviewed 19 doctoral students and 16 supervisors from Canadian universities across all disciplines.
My findings suggest that relational leadership is connected to positive leadership in a symbiotic relationship—they are two sides of the same coin. The relational/positive leadership model (RPL) that emerged from the data analysis can be instrumental for ensuring that doctoral students maintain their well-being and enhance their performance. Data analysis suggests that relational/positive leadership is a spectrum spanning highly relational/positive leaders and non-relational/negative or toxic leaders. Relational/positive supervisors are student-oriented, and they create uplifting experiences for their students with possible negative aspects—normal in any social relationship. However, these negative aspects are few and manageable: the positives outweigh the negatives on this side of the positive spectrum. The RPL side is the optimistic side of the spectrum, comprising realistic supervisors who know that a doctoral program is complex and demanding, requiring their presence, understanding, empathy, compassion and wisdom. Non-relational/toxic supervisors are less people-oriented, valuing self-interest over their students’ interest, and some are absent, or overly authoritarian. They display negative attitudes and create undesirable experiences for their students.
This model can be significant for improving doctoral supervision. The relational/positive leadership approach to doctoral supervision is supported by four influential factors: accessibility, approachability, and psychological presence (AAPP); trust; efficacy; and mentorship. These influential factors are, in turn, nourished by core leadership competencies: ethical, cognitive, emotional, and social. The findings can be used to inform further research and also policy and practice at different levels. At the individual level, supervisors and students can use the RPL model to evaluate and enhance their practices. At the group level, relational/positive supervisors can collaborate and utilize the findings to create a positive culture in each department. At the departmental/institutional level, current policies and programs can be reviewed and improved using this study’s findings.

abstract: PhD


title: Stray Gas Migration in Shallow Groundwater: Gas Dynamics, Mass Transfer, and Environmental Expression

contributor:
Mumford, Kevin
Civil Engineering

subject:
Groundwater
Stray Gas
Multiphase Flow
Mass Transfer
Methane
Dissolution
Gas Dynamics
Environmental Expression
Oil and Gas

abstract:
The objective of this research was to systematically investigate the dynamics of flowing subsurface gases, leading to understanding of mass loading of stray gas in unconsolidated sands, then couple this knowledge to multicomponent mass transfer in homogeneous and heterogeneous systems. To do this, high spatial and temporal resolution visual techniques along with analytical methods were used to study multiphase flow, mass transfer, and surface expression of subsurface gases. Air injections in a small (25 × 25 × 1 cm3) and a large (150 × 150 × 2 cm3) two-dimensional flow cell were performed to quantify gas movement and understand the source architecture resulting from varying leak conditions. This knowledge of free-phase gas migration was then used to better understand mass transfer resulting from flowing gases. A novel visual technique to quantify gas-to-water mass transfer in the flow cells was developed. This technique was then used to quantify mass transfer from flowing carbon dioxide gas under varying aqueous flow velocities and gas injection rates. Finally, experiments were performed in which methane was injected into homogeneous and heterogeneous sand packs in the large flow cell and both aqueous and surface expression were measured.
The results of the experiments performed have allowed for the refinement of the conceptual model for stray gas migration under homogeneous and heterogeneous conditions. Empirical insight on the transport and fate of stray gas has been developed, enhancing our understanding of free-phase gas migration, source architecture of free-phase gas, the complex coupling between gas flow and mass transfer, and the impact of gas dynamics on the surface expression of stray gas. The combined results of this research are intended to allow for the development of sound monitoring techniques, validate numerical modelling efforts, and educate future mitigation solutions for stray gas migration. This work has provided a unique suite of data that can be applied across a variety of applications including gas migration, carbon sequestration, groundwater remediation, and waste disposal.

abstract: PhD


title: Synthesis and Characterization of Fluorescent and Potentially Bioactive DNA-Targeting Platinum Complexes

contributor:
Petitjean, Anne
Chemistry

subject:
Nucleic Acids
Small Binders

abstract:
Guanine quadruplexes (G4s) are non-canonical folded motifs of DNA and RNA which have received growing attention in the past 30 years as they appear to participate in the regulation of cell senescence, the production of proteins, and RNA functions. Specifically, guanine quadruplexes are often more frequently encountered in the gene promoter regions of many human cancer oncogenes. The stabilization of a guanine quadruplex using a small molecular ligand has shown to inhibit transcription, affecting the cancerous activity of the cell.
Chemists can play a significant role through the tuning of ligands. The chemical nature of the binding platform of small molecules can be adjusted in order to improve selectivity towards guanine quadruplex over duplex DNA, which recently has been very effectively achieved in our group, in the development of a platinum-based complex which is highly selective towards guanine quadruplexes.
In this work, the efforts towards synthesizing a luminescent BODIPY ligand to be used for cellular visualization, as well as a potentially bioactive 15-carbon urea fatty acid moiety, which has previously been shown to target the mitochondria and induce apoptosis are described.
The end-goal of this research is to increase the selectivity for G4 motifs, to improve the effectiveness of the platinum complex towards cancerous cells, and importantly to eventually translate this technology in vivo.
In order to effectively study the platinum complexes in cells, an imaging method is required to visualize cell entry and locate these agents. To this end, BODIPY dyes have been synthesized and attached to the G4-targeting Pt complex, and the efficient syntheses of these conjugates are detailed in Chapter 2. Their luminescent properties have been explored in the absence and presence of G4s, and their use as a reference dye for biophysical assays is discussed. The focus of the second ligand is the synthesis of a 15-carbon potentially bioactive urea fatty acid, as well as a 10-carbon test urea fatty acid molecule, and their incorporation into the platinum complex. Their synthesis are described in Chapter 3.

abstract: M.Sc.


title: To Transport and Ravish: Material Manifestations of the Tropes of Transcendental Sublimity in  Wollstonecraft, Wordsworth, Radcliffe, and Austen

contributor:
Pierce, John
English Language and Literature

subject:
The Sublime
Women's Writing
British Romanticism

abstract:
Tropes that romanticize loss of control and violent violation, most frequently of a feminized soul or mind, are pervasive in the discourse arising from the Longinian tradition of transcendental sublime theory. The fundamental premise of this study is that the conceits of sublimity – and most particularly, the echoing trope of transport and ravishment – bear a different social burden in the works of Romantic women as opposed to those of their male contemporaries. The non-fiction writings of Mary Wollstonecraft and Dorothy Wordsworth are illustrative of a disjuncture between the romanticization of lost control and the necessity for almost super-human self control required for women of the era to successfully negotiate their
surroundings. Their travel writings in particular offer an insightful juxtaposition between literal and figurative transport, and they betray an increasing skepticism regarding the practicability, or even the desirability, of the sublime as an aesthetic ideal. The fiction of Ann Radcliffe and Jane Austen likewise capitalizes on the correlation between literal and figurative transport and ravishment in order to criticize the aesthetic hierarchy of their artistic and intellectual environment, as their novels, in differing ways, work to literalize and thereby deromanticize the oppressive aspects of sublime rhetoric. For women of the era, living in a socially encoded state of vulnerability, dependence, and exacting moral culpability, the idea of violent transport culminating in a forceful consummation would not have been the substance of transcendent vision, but of annihilation. This study explores the point of tension between these tropes of gendered oppression codified in the traditionally privileged transcendental discourse and the writing of women who problematized and challenged this rhetoric.

abstract: PhD


title: Electron Recoils In the PICO Direct Dark Matter Detection Experiment

contributor: Physics, Engineering Physics and Astronomy

subject:
Dark Matter
Astroparticle Physics
GEANT4

abstract:
The PICO-40L bubble chamber for direct dark matter detection is finishing the commissioning phase at SNOLAB. The detector will operate for 1 live year before being replaced by the next-generation detector, PICO-500. The elastic scattering of dark matter with the nuclei in the superheated liquid will nucleate bubbles if the energy deposited in the detector is above the threshold energy. Particle identification is achieved using the acoustic and imaging data collected. Other signals may mimic the signature of dark matter. Understanding and eliminating these background signals are critical in the future discovery of dark matter.

Electron recoil induced bubbles have similar signatures as dark matter. However, they are extremely inefficient in bubble nucleation. The electron recoil background levels for PICO-40L and PICO-500 are studied in detail. In order to operate at a threshold that simultaneously maximizes the nuclear recoil acceptance and the electron recoil rejection, limiting the number of expected electron recoil events to $<$1 per live year, both detectors should operate at 13.1$^o$C and 25 psi with a threshold of 2.95 keV. At this threshold, a 141 Bq Cf-252 neutron source and a 33 MBq Co-60 gamma source can be used to calibrate the nuclear and electron recoil response of PICO-40L. Existing sources have sufficient strengths to calibrate PICO-500 to the statistical accuracy required, provided that the calibrations start by the end of 2021.

abstract: M.Sc.


title: Cardiorespiratory Fitness as a Clinically Relevant Risk Factor

contributor:
Ross, Robert
Kinesiology and Health Studies

subject:
Cardiorespiratory Fitness
Exercise
Cardiometabolic Risk
Physical Activity

abstract: The purpose of this dissertation was to provide evidence in support of cardiorespiratory fitness (CRF) as a clinically relevant tool to manage lifestyle-based disease. The objective of Study 1 was to determine whether there is a difference in all-cause mortality risk between CRF achieved through physical activity (PA) (active; CRF-A) compared to the same CRF achieved without (inactive; CRF-I). The main finding of this study was that while both CRF-A and CRF-I were associated with lower all-cause mortality risk, there was no difference in mortality risk between CRF-A and CRF-I. That those with CRF-A achieved the same risk reduction as those with CRF-I underscores the unique importance of PA as the primary determinant of CRF.  The objective of Study 2 was to determine whether the association between CRF and long-term outcomes is explained by changes in cardiometabolic risk (CMR) by exploring whether exercise-induced improvement in CRF and/or waist circumference (WC) is associated with change in CMR. The main finding of this study was that exercise-induced change in CRF was not associated with change in CMR, whereas the greater the exercise-induced change in WC, the greater the change in CMR. The objective of Study 3 was to determine whether submaximal CRF (sCRF) is inversely associated with all-cause mortality risk in adult men and women.  The main finding of this study was that adults who maintained of improved sCRF were less likely to die from all causes during follow-up than were adults whose sCRF decreased. This test provides a unique reflection of cardiovascular health that is a pragmatic alternative to maximal CRF tests. The objective of Study 4 was to determine whether change in estimated CRF (eCRF) is associated with change in measured CRF independent of exercise amount and intensity over 24 weeks. The main finding of this study was that change in eCRF is associated with change in measured CRF over 24 weeks independent of exercise amount but not intensity. In addition, systematic variation was observed between eCRF and measured CRF, highlighting a principal limitation when using eCRF to follow exercise-induced change in measured CRF.

abstract: PhD


title: Long-term response of sockeye salmon (Oncorhynchus nerka) nursery lakes to climate and watershed management activities in British Columbia (Canada)

contributor:
Cumming, Brian Fraser
Selbie, Daniel Thomas
Biology

subject:
Sockeye Salmon
British Columbia
Seton Lake
Anderson Lake
Babine Lake
Paleolimnology

abstract:
Sockeye salmon (Oncorhyncus nerka) are a heavily exploited species. Owing to their large geographical distribution and use of both freshwater and oceanic habitats, sockeye salmon are exposed to various stressors at the local, regional and Pacific-wide scale. As such, assessing the relative influence of these stressors on sockeye salmon populations can be challenging. The goal of this thesis was to further develop our understanding of the influence of local anthropogenic and climate factors on the freshwater nursery lakes upon which sockeye salmon depend. This was accomplished by investigating the impact of watershed disturbances in three large and highly valued sockeye salmon nursery lakes: Seton, Anderson and Babine lakes (British Columbia, Canada). The results indicate that anthropogenic disturbances in the watershed of these nursery lakes changed the pelagic producer communities, which may indirectly and/or directly reduce the capacity of the lake to sustain populations of sockeye salmon. The results also highlighted the importance of the local ecosystems responses to climate change which can modify the nursery ecosystem and indirectly influence the freshwater survival of juveniles O. nerka. This
thesis also investigates the long-term variations in inferred sockeye salmon population dynamics. The reconstruction of the salmon population of Seton Lake over the last ~600 years indicate that the sockeye salmon population of Seton Lake was much larger prior to the onset of commercial harvesting. The low frequency (~300 year), high-amplitude (~3‰ oscillation in δ15N) fluctuations displayed by the Seton Lake records appeared in anti-phase with some Alaskan populations, which may indicate that coastal oceanic processes at the mouth of the Fraser River regulates the Seton Lake sockeye salmon population through a regional mechanism, other than the Alaskan Gyre and California current. Together, the findings of these studies suggest that predicting O. nerka production in the future may become increasingly challenging because of the simultaneous and potentially additive effects of local and Pacific-wide changes in climate and anthropogenic stressors.

abstract: PhD


title: Packaging and Layout Optimization Using the Dynamic Vector Fields Method

subject:
Packaging Optimization
Packing Optimization
Layout Optimization
System Design
System Optimization
Vector Fields

abstract:
Ever-increasing environmental regulations and competition within industry to create the best performing, most cost-effective product has driven the development of computational design, analysis and optimization tools. Many tools exist which allow engineers to optimize specific aspects of their designs, but there are few optimization tools that can inform system level design. The complexity of system level design is a product of the many interactions, functional requirements and the layout of constituent parts and assemblies. System layout and packaging can have significant effect on the overall system performance, affecting metrics such as cost, and overall efficiency. Due to the complexity and scope of system design, there is significant benefit that could be realized from an optimization tool informing the packaging and layout of components and assemblies within a system.
This thesis presents a novel method for solving packing, packaging and layout optimization problems. This method, the Dynamic Vector Fields method, solves packing and packaging optimization problems by dynamically simulating the translation and rotation of components and assemblies over time. The final layout of objects/components is determined by dynamic vector fields, which impart acceleration onto objects. These dynamic vector fields represent the problem’s objectives, constraints, and different physical interactions between objects and their environment. Using the Dynamic Vector Fields method presents several advantages; multi-objective problems can be solved by using dynamic vector fields representing different objectives, various physical effects can be represented using dynamic vector fields, relaxation of object collisions and overlap can help reduce initial condition dependence, and the scalability of the method allows it to be applied in various contexts.
The development of the theory, mathematics and algorithms behind the Dynamic Vector Fields method is detailed in this thesis. Capabilities to pack non-convex geometry, and pack objects into non-convex design domains are developed, allowing practical problems to be solved. Various test cases are presented, demonstrating the capabilities and efficacy of the method in solving packing type problems.

abstract: PhD


title: “La fédération impériale, voilà notre ennemie”: Honoré Mercier and Public Opinion on Imperial Federalism as Seen Through the Montreal Press, 1885-1893

contributor:
den Otter, Sandra
McNairn, Jeffrey
History

subject:
Imperial Federalism
Imperial Federation
Honoré Mercier
Laurent-Olivier David
Confederation
Provincial Autonomy
Public Opinion
Montreal Press
Sohmer Park
Québec Nationalism
Canadian Politics
Canadian History
Québec History
British World
French-Canadian
Political Spectacle
Elite Opinion
Mercier
Newspapers in Montreal
fédération impériale
Québec Politics
British Empire
Imperial History
Colonial History

abstract: This thesis examines Québec Premier Honoré Mercier's (1887-1891) critique of imperial federalism from 1885-1893 and its impact on public opinion in Montreal by analysing press coverage. Hostility to imperial federalism was nurtured and maintained by Mercier's continuous, multi-pronged and organised critique. This opposition to imperial federalism has been overlooked as a key issue in Mercier's political strategy. Disappointment with Confederation and the centralising tendencies of the federal government, coupled with surging French-Canadian nationalism, allowed Mercier to successfully frame imperial federation as a threat to provincial autonomy and to French-Canadian survival. Mercier's strategy relied on rhetoric, spectacle and political savvy in a successful example of elite opinion formation. An 1890 motion in the Quebec Assembly condemning imperial federation and an 1892 oratory contest on Canada's future at Sohmer Park, in Montreal, are examined through Montreal press coverage to illustrate the effectiveness of Mercier's critique that transcended partisan and ethnic divisions.

abstract: M.A.


title: Public Transportation and Residential Location Choice

contributor:
Jaworski, Taylor
Lloyd-Ellis, Huw
Vierø, Marie-Louise
Economics

subject:
Public Transportation
Residential Location Choice
Counterfactual Simulation
Commute Mode Choice

abstract: In this thesis, I develop and apply a structural framework to analyze the impacts of public transportation infrastructure expansions. In the second chapter, we incorporate rapid transportation access into an equilibrium residential location model and estimate the model with microdata from Vancouver. Simulating an expansion of Vancouver's rapid transportation network, we find dwelling prices increase in both newly connected neighbourhoods and neighbourhoods with pre-existing access to the network. In the third chapter, I develop and estimate a model of households simultaneously choosing their commute mode and residential location. Using geographic information system (GIS) data, I calculate public transportation times between each neighbourhood. Using the estimated model, I simulate households' residential and commute mode choices under counterfactual public transportation times, and analyze the changes in public transportation use, travel time, and consumer surplus across income groups.

abstract: PhD


title:
Defiance, Reclamation, and a Call to Mino Bimaadiziwin/ The Good Life
 Through Ceremonial Performance Praxis

contributor:
Robinson, Dr. Dylan
McKegney, Dr. Sam
Cultural Studies

subject:
Theatrical Indigeneity
Five Protocols
Decolonization
Theatre
Indigenous Theatre
Devised Work
Wani'/Lost
Anishinabek
Anishinaabekwe
Mino Bimaadiziwin/ the Good Life
Performance Ceremony
Ancestors
Lineage of Permission
Embodied Defiance
Performative Reclamation
Stone Medicine
Unlearning
Grandfather and Grandmother Stones
Sovereign Indigenous Knowledge
Ceremony
Performance
Relic of Dispossesion
Ceremony as (re)storying
State Apparatus
Colonial
Decolonial
Loss
Memory
Autobiography
Carrying
Land
Water
Racism in Theatre
Oskabewis
Future Ancestor
Protocols
Ways of Being
Belonging-Matrix
Research Creation Project
Bundle
Kaandossiwin
Unsettle
Memory as Prophesy
Ceremonial Praxis
Knowledge Keeper

abstract:
This MA thesis is a bundle that weaves time, space, and form. It includes personal narrative, considerations and reflections on creation and research as well as the production/ performance script, stage directions, and processes used for the ceremony-performance "Wani’/Lost."
 Supported by the theoretical and cultural context that gave rise to this work, this bundle includes reflections on a week-long practice-based research devising process that contributed to the "Wani’/Lost" performance staged at the Ka’tarohkwi Festival of Indigenous Arts. This bundle also reflects on the devising process and the performance work ahead. These strands of reflection along with the embedment of spatial and performative theory, propose an evolving set of actions and resurgent framework for Indigenous theatrical performance. The writing also serves to disrupt the MA entity and offers ideas on how one might begin to unsettle the colonial history of theatre and the state apparatus known as ‘Canadian’ theatre. Rather than dictating instructions for readers to follow, these entwined notions serve as interventions and prompts to unravel how loss makes us not see ourselves. This bundle also asks how we can embody intimate acts of defiance, reclamation, and a call to Mino Bimaadiziwin/ the Good Life.

abstract: M.A.


title: Reading Between the Lines:  Welfare Chauvinism and Depictions of Deservingness in Canadian Print News

contributor:
Goodyear-Grant, Elizabeth
Banting, Keith
Political Studies

subject:
Welfare Chauvinism
Deservingness
Framing
Canada
Social Assistance
Media
Canadian Politics
Social Policy
Media Framing
Indigenous Peoples
Immigrants

abstract:
Welfare chauvinism – the barring of minority groups from access to social benefits – is a major issue affecting many welfare states around the world. Although at first glance Canada appears to be an “exception” to this exclusionary sentiment, more recent evidence suggests that Canadians are increasingly inclined to restrict both immigrants’ and Indigenous peoples’ access to social assistance in Canada.
This dissertation examines how perceptions of immigrants’ and Indigenous peoples’ deservingness are codified and transmitted through public discourse in Canada, specifically analyzing the ways that they are framed in news media. Exploring coverage of welfare recipients in Canadian major dailies, this dissertation analyzes the ways that immigrant and Indigenous beneficiaries of social assistance are depicted differently from non-Indigenous, native-born Canadians when it comes to a variety of deservingness perceptions, and asks how these deservingness frames affect public opinion about redistribution more generally. Utilizing three original data sets, this dissertation includes:
1)	A framing analysis that compares the framing of immigrant, Indigenous, and general recipients of welfare across a number of deservingness markers in print media.
2)	A public opinion survey that analyzes perceptions of deservingness for immigrant, Indigenous, and general Canadians.
3)	A news framing experiment that tests how the deservingness frames found in news coverage of welfare recipients affect readers’ attitudes toward Indigenous, immigrant, and general beneficiaries of social assistance.

This project principally finds that immigrants are framed as significantly more deserving than general Canadians and Indigenous peoples when it comes to perceptions of reciprocity – assumptions about economic contributions to Canada – in news coverage of welfare, while Indigenous peoples are framed as slightly more lazy than non-Indigenous and immigrant beneficiaries. The results of the experiment suggest that the deservingness frames elicit substantive effects on support for recipients’ access to welfare but are conditioned by the recipients’ identity. In effect, the results of the study suggest that deservingness cues in news coverage can affect public perceptions about who ought to benefit from social assistance that may have larger effects on attitudes toward redistribution more generally in Canada.

abstract: PhD


title: Multifunction Radio Frequency System Design Using Nonlinear Models

contributor:
Saavedra, Carlos
Bray, Joey
Electrical and Computer Engineering

subject:
Electrical Engineering
RF
System Design
X-Parameters
Polynomial Modeling
Frequency Planning
Multifunction Systems
Software Defined Radar

abstract:
Multifunction radio frequency (RF) systems provide a general-purpose hardware platform for designers to implement arbitrary waveform transmission and reception. In this thesis, a multifunction RF transceiver is designed, simulated and tested. The transceiver was designed for radar applications operating at X-band (8 to 12 GHz) and is wideband, thereby providing the designer with a wide wireless window through which they can simultaneously transmit and receive multiple signals. The system is constructed entirely using commercial off-the-shelf components; the design therefore
consists of frequency planning, specifying a system architecture and selecting appropriate components.

The final transceiver design was constructed using a homodyne architecture, which contains a mixer in the transmitter and the receiver in order to perform frequency translation between baseband and X-band. Using a mixer in the system design requires that a frequency plan be developed in order to ensure that image and sideband overlaps do not occur at the mixer outputs. Frequency planning rules were therefore developed for wideband applications and were used to specify an instantaneous bandwidth of 1.1 GHz, the largest for a multifunction system. A new criterion, called the radar metric, was then developed to quantify the design specifications of the RF system.

The frequency plan and radar metric were used to specify the  final system design, which could then be simulated. In order to acquire accurate simulation results, each component was individually measured and characterized. The amplifiers in the
system were characterized using nonlinear models so that their harmonic behaviour could be accounted for. Wideband systems are particularly susceptible to harmonic interference since it is possible for harmonics to enter the large frequency window provided by the system, hence the need for accurate nonlinear modeling. Finally, a prototype was constructed which showed that the system was able to generate a maximum transmit power of 13.56 dBm, with a receiver noise figure of 2.33 dB. Moreover, simultaneous signals were transmitted and received through the system, thereby verifying the multifunctional capabilities of the transceiver.

abstract: M.A.Sc.


title: Why Sport? An Examination of Youth Sport Program Consumption Behaviours in Canadian Ice Hockey Parents

contributor:
Côté, Jean
Kinesiology and Health Studies

subject:
Sport Psychology
Youth Sport
Sport Parents
Ice Hockey
Youth Ice Hockey

abstract:
Participation in youth sport programming has been shown to influence many outcomes associated with positive development in children and young adult populations. Despite this, the waning accessibility of youth sport programs through more expensive and time-intensive activities has made participation increasingly difficult for many children and their families. While many young athletes undoubtedly make important choices when it comes to facilitating their involvement within youth sport, parents could be seen as ultimately responsible for the final selection of youth sport program type and intensity due to their role as primary caregivers and financers. Although previous work has explored the ways in which the parents of young athletes behave within the youth sport context as well as how these behaviours may influence their children’s sport participation in various ways, little research appears to examine how sport parents make decisions about the types of sport activities in which their children participate. As such, the present study sought to conduct 15 semi-structured interviews with the parents of children participating in recreational, competitive, as well as a high-performance minor ice hockey programs in Canada with the intention of examining what factors might influence their youth sport program choices and what the decision-making processes behind these choices might look like.
It was found that parents encouraged their children to participate in ice hockey programs as they saw the activity as a positive means to foster athletic as well as non-athletic development, to make friends, and because it was something that their children enjoyed. Parents also recognized that, within the Canadian context, ice hockey held specific benefits for their young athletes due to the sport’s popularity when compared to other extra-curricular activities. Despite these benefits however, parents also discussed barriers to participation highlighting the social climate within organizations, excessive travel, and high cost as factors in their unwillingness to remain involved in particular sport organizations. This thesis discusses the practical and theoretical implications of these findings within the context of the extant sport parent and sport psychology literature, potential study limitations, and future directions in the continued exploration of this area.

abstract: M.Sc.


title: Mechanical stretch increases Kv1.5 current through interaction between the S1-S2 linker and N-terminus of the channel

contributor:
Zhang, Shetuan
Biomedical and Molecular Sciences

subject:
Kv1.5
Electrophysiology
Mechanical Stretch
Voltage-Gated Potassium Channel

abstract: The voltage-gated potassium channel Kv1.5 mediates the ultra-rapid delayed rectifier current (IKur) in the heart, important for human atrial repolarization. In physiological conditions cardiomyocytes continuously undergo mechanical load, a parameter influenced by blood pressure and fluid retention. Dysfunction of Kv1.5 has been associated with atrial fibrillation, an arrhythmia linked to hypertension and atrial dilation, risk factors that involve cardiomyocyte stretch. In the current project, the effects of mechanical stretch on Kv1.5 channels were investigated. Mechanical stretch was induced by centrifuging cells at 70 × g for 5 minutes or subjecting HEK 293 cells and neonatal rat ventricular myocytes expressing Kv1.5 to low osmolarity cell culture medium (LO) leading to a 33% increase in cell size. The results demonstrated mechanical stretch induced by LO increased Kv1.5 current (IKv1.5) at 20 mV and above (P < 0.01) without altering membrane expression and such an increase required the long, proline-rich S1-S2 linker of the Kv1.5 channel to be intact. The LO effect also required the N-terminus, which contains the binding domain for endogenous Src tyrosine kinase that mediates IKv1.5 inhibition. Disrupting the Src binding domain of Kv1.5 through N-terminal deletion or point mutations abolished the mechanical stretch-mediated effect on IKv1.5. The results further revealed that the S1-S2 linker is coupled with the N-terminus; deletion of the N-terminus up to amino acid residue 209 altered the conformation of the S1-S2 linker such that S1-S2 linker was no longer susceptible to proteinase K (PK) cleavage. The Kv1.5 voltage dependence of inactivation which is regulated by the N-terminus was also altered by PK cleavage of the S1-S2 linker, revealing an indirect link between the N-terminus and S1-S2 linker. It is concluded that the S1-S2 linker of Kv1.5 represents a mechanosensor; when targeted by mechanical stretch, a change in N-terminal conformation occurs, relieving Src-mediated tonic channel inhibition, resulting in an increase in IKv1.5. This study reveals a signalling pathway linking mechanical stretch and Kv1.5 activity, providing a potential mechanism for stretch-induced atrial fibrillation.

abstract: M.Sc.


title: Multiple Perspectives on Teaching Excellence: a Case Study

contributor:
Berg, Derek
Education

subject:
Teaching Excellence
Teaching Merit Pay
Conformity Education

abstract: Teacher compensation is the largest part of the monies spent by school boards in Ontario annually and currently all teachers are paid following a grid system that rewards teachers for time spent in the system rather than the quality of their work. For example, in 2018-19, the York Region District School Board’s instructional costs were 59% of their total budget at over 800 million dollars. An exemplary teacher costs the province and its school boards just as much as a poor one. Consider the possibility that teachers could be paid on a merit based model. There is currently no way to differentiate between poor and exemplary (or any other part of the spectrum) teachers. This research attempted to utilize an existing set of characteristics of excellence (Grieve 2010) to prepare a foundation upon which a methodology could be built to standardize a method to identify exemplary educators. The goal of this study was to understand the long-term perceived effect that George Turcotte has had on his students. Mr. Turcotte has been teaching elementary school in Kingston since 1966 and has taught in the public, the separate, and private systems over those years. He is widely acknowledged locally as an excellent teacher if not entirely unique. Any attempt to create a methodology of measuring excellence would need to include unique educators such as Mr. Turcotte.

abstract: M.Ed.