title: Healthcare access experiences and concerns of Canadians with multiple sclerosis

contributor:
Finlayson, Marcia
Rehabilitation Science

subject:
Multiple Sclerosis
Healthcare access
Mixed-methodology
Patient-centered care

abstract:
Canadians with multiple sclerosis (MS) are high users of healthcare services yet report multiple unmet needs. The reasons for this situation have not been explored, however international literature suggests that issues in gaining equitable access to appropriate healthcare may be the culprit.
The overall purpose of this dissertation was to investigate access to healthcare, in the Canadian context, from the perspective of persons with multiple sclerosis (PwMS). Access was examined through the lens of the Candidacy Framework, which defines access to healthcare as a multidimensional process including an individual’s path to care seeking, their entry into healthcare, and their use of services.
A multiphase mixed-method design was used to address the dissertation aims. First, a qualitative study using focus groups and individual interviews was conducted to understand the experiences of PwMS as they access healthcare services to manage their condition. Next, the qualitative data from study 1 were re-evaluated to explore the alignment between the experiences of access described by PwMS and the stages of the Candidacy Framework. Finally, a cross-sectional survey was conducted to determine the most pressing access concerns of Canadians with MS.
The qualitative work identified a lack of patient-centered care, low availability of neurologists and healthcare providers with MS-related knowledge, as well as a lack of affordable allied and complementary care as major causes of reported unmet needs. In fact, many PwMS felt that care seeking was not worth it until a crisis arose, due to poor past experiences through which needs remained unmet. Together this evidence provided important theoretical insights to the field of access by demonstrating the importance of including help-seeking behaviour to examinations of access to care.  Survey findings indicated that PwMS prioritized low availability to healthcare providers with MS-related knowledge and affordability to services aiming to promote and maintain wellness as their top access concerns.
The dissertation findings provide solid foundational evidence regarding the healthcare access experiences of Canadians with MS, which can be used to drive research and advocacy planning that better meet the access needs of this population.

abstract: PhD


title: EXAMINING THE LONG-TERM ECOLOGICAL CONSEQUENCES OF GOLD MINING OPERATIONS, URBANIZATION, AND CLIMATIC CHANGES ON SUB-ARCTIC LAKES NEAR YELLOWKNIFE (NORTHWEST TERRITORIES, CANADA) USING DIATOMS AS PALEOENVIRONMENTAL INDICATORS

contributor:
Smol, John
Biology

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.

rights: Attribution-NonCommercial-NoDerivs 3.0 United States

subject:
paleolimnology
sub-Arctic lakes
environmental change
precious metal mining
multiple stressors
diatom (Bacillariophyceae)

abstract: The mineral resource potential of Canada’s North has been recognized since the early 20th century with mines operating across all three territories. However, the long-term biological consequences of Northern mining operations and associated anthropogenic activities on surrounding freshwaters have not been investigated extensively. The sub-Arctic lakes around the City of Yellowknife (Northwest Territories) provide an important opportunity to fill this knowledge gap by examining the long-term cumulative impacts of past gold mining operations, land-use changes related to urbanization, and regional climatic changes on aquatic biota. In this thesis, diatom-based (Bacillariophyceae) paleolimnological approaches were used to assess the long-term biological responses to the multiple environmental stressors mentioned above through space and time. A spatial survey of diatom assemblages from the surface sediment of 33 lakes around Yellowknife indicated that assemblage composition was strongly influenced by variables related to lake-water nutrient concentrations and ionic composition in the water column, while metal(loid) contaminants (i.e. antimony, arsenic) associated with gold mining activities played a secondary role. Analyses of diatom assemblages from ten well-dated sediment cores from lakes along a gradient of anthropogenic activities (i.e. mining and urbanization) recorded notable shifts over the last ~200 years. The high species turnover in the lakes closest to the mines and the city were indicative of metal(loid) pollution from past gold mining activities (e.g. roaster stack emissions, accidental spills from tailings pond) and eutrophication from land-use changes (e.g. sewage disposal, developments in the catchment). The impacts of climate-mediated changes were also apparent in both the urban and remote lakes. The synergistic effects of warming and nutrient enrichment led to striking changes at Niven and Jackfish lakes. Recent diatom assemblage composition in all lakes was substantially different from pre-disturbance periods, which suggests that the sub-Arctic lakes around Yellowknife have crossed critical limnological thresholds in response to both anthropogenic activities and climatic changes. The long-term perspectives gained from this research contributes to the growing body of knowledge on biological responses to Northern mining contamination and urbanization in a warming world.

abstract: PhD


title: Quantifying and qualifying ecosystem services to enhance Natural Heritage System Planning:  A case study in Halton, Ontario Canada

contributor:
Mabee, Warren
Geography and Planning

subject:
Natural Heritage System Planning
ecosystem services
Halton Region, Ontario, Canada

abstract:
This dissertation explores a means of enhancing current approaches to Natural Heritage System
planning through the explicit recognition of the value of natural areas on the landscape. The
identification of various landcover types captured within a Natural Heritage System and the
ascription of cumulative ecosystem service values by landcover type is posited as a means to
enhance Natural Heritage System Planning. The integration of ecosystem services into the
Natural Heritage System planning process as a means of increasing social license for NHS
planning is explored. Using Ontario’s Halton Region as a case study, the effectiveness of NHS
planning in capturing and maintaining different landcover types is assessed. Landcover
classifications are used as the basis to determine ecosystem service values. A series of surveys,
interviews, and workshops are used to evaluate stakeholder perspectives on both NHS and
ecosystem services, and explores the potential of integrating the two. NHS is an effective
means of capturing important ecological landcover types; more than 90% of forests and
wetlands areas are captured in Halton’s NHS, comprising 22,800 ha out of the total 49,990 ha
designated within the system. Halton’s NHS captures an estimated $645 million per year in
ecosystem value, which is 85% of the Region’s total estimated value; regulating services are
declining, while cultural services are increasing. While stakeholders across the Region are
aware of the need for NHS, strong negative perceptions of the process from industrial
stakeholders suggest that the process has not yet achieved the threshold for social license. The
study concludes that integration of ecosystem services into NHS planning could improve
transparency and communication around the process, but that stakeholders would be more
likely to accept this integration if the process was framed as a response to a common goal, such
as managing impacts of climate change. The research suggests that quantifying ecosystem
service levels rather than valorizing these services might be preferable. Updates to Ontario’s
Ecological Land Classification systems might help to improve assessment of ecosystem services
in the future; NHS planning should also be updated to provide a more transparent mechanism
of communicating what landcover types are delineated and protected through these systems,
to aid in landscape-level planning. Sharing information widely before discussing policy options
is essential to increasing transparency, building community consensus, and achieving lasting
social license for long-term NHS protection.

abstract: PhD


title: Pulse fitting for event localization in high purity germanium point contact detectors

contributor: Physics, Engineering Physics and Astronomy

subject:
Germanium detectors
PPC
HPGe
pulse fitting
event localization
position resolution
Majorana demonstrator

abstract: P-type Point Contact (PPC) detectors are used in rare-event searches, such as neutrinoless double-beta decay and dark matter searches, due to their low radioactive backgrounds and low energy thresholds. The Majorana collaboration operates the Majorana Demonstrator experiment, which uses high purity germanium (HPGe) point contact (PPC) detectors with the goal of experimentally observing neutrinoless double-beta decay. Neutrinoless double-beta decay is an experimental proof of the hypothesis that neutrinos are Majorana particles. Observing this decay can give us major insights into physics beyond the Standard Model of particle physics. But to observe neutrinoless double-beta decay, experiments have to be designed to detect the faintest signals because the current best lower limit of the half-life of the decay is ~ 10^25 years. This work aims to determine the location of the energy depositions in PPC detectors using the charge signal that is collected from the single point contact electrode. By comparing the charge signals to a library of simulated signals, events can be localized, in some cases, with a resolution of 1mm. This is of interest in localizing low energy backgrounds in these types of detectors.

abstract: M.Sc.


title: Interface shear behaviour of different geomembranes with rough surfaces in Heap Leaching applications

contributor:
Abdelaal, Fady
Civil Engineering

subject: direct shear test, ageing, interface shear, heap leach pad, geotextiles, geomembranes, geocomposite drain, textured geomembranes, geomembranes with rough surfaces.

abstract:
The interface shear strength properties of the different geosynthetic layers of the liner system are examined
for heap leach pads applications. A series of large scale direct shear tests is used to examine the
effectiveness of four geomembranes (GMBs) with different surface roughness with different soil subgrades,
geotextiles (GTXs) with different mass per unit areas, and a geocomposite drain (GCD) at moderate to high
normal stresses.

Four different subgrades, including sand, two different coarse-grained underliners, and clay
representing the layers directly underlying the GMB liner in heap leach pads, are used to examine the shear
strength of the GMB-Subgrade interfaces at normal stresses between 50 and 1000 kPa. It was found that
increasing the normal stresses can change the mechanisms contributing to the shear resistance at the
interface. This resulted in a statistically insignificant increase in the interface friction of the GMB-Granular
soils interfaces when using GMBs with surface roughness relative to the smooth GMB. Furthermore,
depending on the type of subgrade, establishing the shear envelopes over a wide range of normal stresses
may over/underestimate the shear strength at the field stresses even when linear regressions present the best
fit for the data.

The effect of using GTX cushion to protect the GMB liner from excessive punctures at high stressed
zones of the pad on the interface shear behaviour of the liner system is investigated by examining different
GMB-GTX interfaces. Using GMBs with high surface roughness and/or decreasing the mass per unit area
of the GTX increased the peak friction angles of the GMB-GTX interface. However, the shear strength of
these GMB-GTX interfaces was still lower than the shear strength of most of the GMB-Subgrade interfaces
even when the smooth surface of the GMB was in contact with the subgrade. Additionally, while preageing
the GTXs to low mechanical properties prior to the direct shear experiments was found to increase the peak
interface friction angles of different single layer GTXs due to the softening of geotextiles, it resulted in aniii
internal failure of a heat bonded two-layer GTX at low shear displacements. This was due to the reduction
in the bond strength between the two layers of the GTXs due to chemical degradation of the GTX.

abstract: M.A.Sc.


title: Exploring Victimization Experiences of Sexual Minority Adolescents and their Associations with Mental Health and Help-Seeking Behaviours: A Minority Stress Perspective

contributor:
Craig, Wendy
Psychology

subject:
Victimization
Teen Dating Violence
Minority Stress Theory
Sexual Minority
Bullying

abstract: Victimization in adolescence is associated with a variety of negative psychopathological and social outcomes, and is predictive of recurrent victimization over the lifespan (Wolke & Lereya, 2015; Feiring & Furman, 2000).  Youth who identify as LGBT2Q+ (lesbian, gay, bisexual, transgender, two-spirited, queer/questioning, etc.), also known as sexual minority youth, are at an increased risk of experiencing both peer and romantic victimization (Lee, 2013; Reuter, Sharp, & Temple, 2015), are more likely to experience mental health problems (Fish & Pasley, 2015), and are less likely to seek help after being victimized (Gallopin & Leigh, 2009), compared to their sexual majority peers. Meyer’s Minority Stress Theory (2003) provides a promising framework through which researchers may explain the relationship between sexual minority status and negative developmental outcomes.  This theory posits that stressors specific to an individual’s minority status mediate the relationship between sexual minority status and physical and mental health problems (Meyer, 2003).  The current thesis consisted of two studies, which used a Minority Stress Theory framework to understand how minority stress may mediate or moderate the relationship between peer and romantic victimization, and mental health problems or help-seeking behaviours. Results indicated that sexual minority high school students in grades 9-12 were significantly more likely to experience verbal/emotional abuse, coercive/controlling behaviours, and sexual abuse, in the peer context. Additionally, minority stress mediated the relationship between romantic victimization and mental health. This research may inform future intervention programs targeted at LGBT2Q+ youth and ensure their unique needs are being integrated into anti-bullying initiatives.

abstract: M.Sc.


title: Quality Estimation for Scarce Scenarios within Mobile Crowd Sensing Systems

contributor:
Hassanein, Hossam
Zorba, Nizar
Electrical and Computer Engineering

rights: Attribution-ShareAlike 3.0 United States

subject:
Mobile Crowd Sensing
MCS
Participant Selection
Participant Recruitment
Crowdsourcing
Crowd sourcing
Crowdsensing
Crowd Sensing
Human in the loop
Quality Estimation
Quality Metric
Median Absolute Deviation (MAD)
Bootstrap
Jackknife
Entropy
Internet of Things
MCS Coverage
Coverage Quality
Operations Research
Data Analysis

abstract: Mobile Crowd Sensing (MCS) is a paradigm that exploits the presence of a crowd of moving human participants to acquire, or generate, data from their environment. As part of the Internet of Things (IoT) paradigm, MCS serves the quest for more efficient operation of a smart city. Big data techniques employed on this data produce inferences about the participants' environment, the smart city. However, sufficient amounts of data are not always available. Sometimes, the available data is scarce as it is obtained at different times, locations, and from different MCS participants who may not be present. As a consequence, the scale of data acquired maybe small and susceptible to errors. In such scenarios, the MCS system requires techniques that acquire reliable inferences from such limited data sets. To that end, we resort to small data techniques that are relevant for scarce and erroneous scenarios. In this thesis, we discuss small data and propose schemes to tackle the problems associated with such limited data sets, in context of the smart city. We propose two novel quality metrics, MAD-Q and MADBS-Q, to deal with small data, focusing on evaluating the quality of a data set within MCS. We also propose an MCS-specific coverage metric that combines the spatial dimension with MAD-Q and MADBS-Q. We show the performance of all the presented techniques through closed-form mathematical expressions, with which simulations results were found to be consistent.

abstract: M.A.Sc.


title: Stratabound Zinc Mineralization at the Salerno Lake and Calumet-Sud Occurrences hosted in the Proterozoic Central Metasedimentary Belt Marbles of the Grenville Province, Canada

contributor: Geological Sciences and Geological Engineering

subject:
Zinc
Economic Geology
Grenville Province
Metamorphism
Central Metasedimentary Belt
Grenville Supergroup
Skarn

abstract: High-grade marbles of the southeastern Central Metasedimentary Belt in the Grenville Province host several stratabound zinc deposits and occurrences, interpreted in previous work to have been formed from exhalative brines during carbonate sedimentation (SEDEX-type). However, the results from detailed mapping, paragenesis, mineral chemistry, and lithogeochemistry at the Salerno Lake (Ontario) and Calumet-Sud (Quebec) occurrences revealed that syenite, carbonatite, and felsic intrusions occur proximal and may have contributed to the zinc mineralization. At the Salerno Lake occurrence, yellow (Fe- and Mn-poor), intrusion-proximal sphalerite is associated with apatite displaying elevated concentrations of F, Na2O, and SO3, similar to apatite in the intrusive rocks. Moreover, both the proximal hydrothermally altered marble and meta-syenite contain elevated K2O, Al2O, TiO2, Ba, Sr, Rb, Ce and Nd. Red sphalerite (Fe- and Cd-rich) occurs as overgrowths on yellow sphalerite in the proximal zones and extends along bands in the distal zones and is associated with apatite and graphite. Calumet-Sud shares similar mineralogical relationships. I propose that the marble-hosted zinc mineralization is epigenetic and had input of fluids that exsolved from or interacted with the alkaline magmatic rocks particularly in the proximal zones. The stratabound controls on sphalerite mineralization is interpreted to be due to the interaction of magmatic and possible basinal mineralizing fluids with favorable reduced-carbonate layers rich in organic matter and phosphate. Amphibolite-facies metamorphism and deformation have caused changes in the textures of the ore, but the compositional signature of the mineralized zones is interpreted to represent that of the original hydrothermal system.

abstract: M.Sc.


title: Evaluating conservation strategies for a threatened population of gray ratsnakes (Pantherophis spiloides)

contributor:
Lougheed, Stephen
Biology

subject:
Conservation Biology
Animal Behaviour
Herpetology

abstract: Wildlife populations across the globe are declining due to the effects of increasing anthropogenic activities. Among the most vulnerable taxa are snakes, which face several threats including road mortality and habitat loss. To combat such threats, several different conservation techniques have been implemented. Roadside barrier fencing is designed to reduce adult mortality by preventing snakes from accessing the road, while artificial nesting sites serve to increase recruitment. Despite their growing use, however, these strategies are seldom rigorously tested before or after implementation. In this study, I examined the effectiveness of roadside barrier fencing and artificial nest boxes for gray ratsnakes (Pantherophis spiloides), a species at risk in Canada. The goals of my research were to (1) determine the fencing design that prevents gray ratsnakes from successfully climbing over, and (2) determine the environmental variables that influence the use of nest boxes by gray ratsnakes. To do this, I captured and placed gray ratsnakes within fencing enclosures composed of different heights, materials, and shapes commonly used in roadside barrier fencing. I then measured whether or not snakes were able to escape, as well as different behavioral responses. I also placed nest boxes throughout various habitats and monitored their environmental conditions throughout the incubation period before checking them for snake eggs. My study revealed that fence material played a significant role in whether or not a snake could climb it, and found a significant interaction between height and shape on snake climbing success. Further, I found that snakes were less willing to climb fencing that was higher and made out of hardware cloth than vinyl sheeting. I also found a near-significant relationship between whether or not a nest box was used and a combination of internal temperature, moisture, and canopy cover. Nest boxes that were used featured higher internal temperatures, moisture, and mid-range canopy covers; however further investigation is needed due to lack of power given the small sample size. My study highlights the importance of identifying and rigorously investigating knowledge gaps surrounding conservation strategies, to maximize their effectiveness and avoid wasting already-limited conservation funding.

abstract: M.Sc.


title: Printing of Electrochemical Energy Storage Device Components

contributor:
Barz, Dominik P. J.
Docoslis, Aristides
Chemical Engineering

subject:
Materials printing
Electrochemistry
Graphene nanoplatelets
Dispersion stability
Hydrogel electrolytes

abstract:
Materials printing is a versatile technology used in a wide range of industrial-scale manufacturing processes that require high-precision transfer of materials on different
substrates. Despite the numerous studies available for contact/non-contact printing, processing of the printed structures, and development of novel inks, there
is still a lack of understanding. In this work, we report on the systematic development of printing and processing techniques and the formulation of stable conductive
inks to fabricate the components of energy storage systems. First, we investigate the printing and sintering schemes for multi-layer inkjet printed films on a glass substrate
to achieve the desired conductivity and thickness. A semi-empirical model is developed by modifying the well-known Fuchs-Sondheimer Mayadas-Shatzkes
model to predict the resistivity of multi-layer nanoparticle metal films. Second, we study different aspects of direct writing of Newtonian liquids, such as jet stability,
jet curvature, and equilibrium profile of a printed line on a substrate. This study allows us to determine the distance between the nozzle and substrate and
control the print resolution on a substrate. Third, we prepare the stable graphene nanoplatelets (GNP) dispersion in water using a minimal amount of graphene oxide
as a dispersant. The stability mechanism, sheet interactions, and the influence of dispersion pH are studied by employing the extended Derjaguin-Landau-Verwey- Overbeek (XDLVO) theory. The rheology of the dispersions is examined and different liquid crystal phases are identified. A dispersion is printed on a flexible substrate and the printed films showed favorable conductivity and adhesion even under bending conditions. Finally, we introduce a novel Zn-Cu battery with and without the use of a separator. The half-cell electrolytes are prepared using polymer hydrogels. The performance of the device is evaluated using electrochemical methods, including cyclic voltammetry, galvanostatic charge-discharge cycles, and electrochemical impedance spectroscopy. We also fabricate and test a printed separator-less battery where the copper electrode and current collectors are prepared using the directwrite printing. Its unique performance without a separator, low-cost materials, and hydrogel electrolytes make it potentially a suitable choice for a wide range of applications as a portable and flexible power source.

abstract: PhD


title: Wonder Turners and Other Optical Oddities:  A history of 19th century inventions and their influence on the perception of time, motion and attention.

contributor: Film and Media (Screen Cultures and Curatorial Studies)

rights: Attribution-NonCommercial-ShareAlike 3.0 United States

subject: optical toys

abstract:
Early recording devices, inventions and optical toys, such as the thaumatrope and the zoetrope, demonstrated natural causes for optical phenomena and had a direct influence on our understanding of visual perception. In this paper, I highlight influential inventors, scientists and artists who contributed to the field of optics, chronography, and subsequent methods of visualizing time and movement. These investigations advanced our understanding of optics, and impacted the study of time, motion and attention. Optical toys, also known as philosophical toys, presaged the use of media and technology in education. This exploration into their history will help steer my future research into the use of traditional animation techniques in education. In addition to optics, much can be learned from these toys. The immersive, hands-on nature of optical toys make them especially appealing and provides connections to a variety of subjects and curriculum.
Optical toys provide an opportunity for students to participate in creating both the form, by making the toy itself, and the content or story that the toy tells. By placing them in their historical context, optical toys provide a window into the roots of children's media culture and its relationship to education.

abstract: M.A.


title: Sick Religion: Towards a Genealogy of Hysterical Stigmata

subject: Research Subject Categories::HUMANITIES and RELIGION

subject: stigmata

subject: hysteria

subject: psychiatry

subject: medicine

subject: Catholicism

abstract: In 2016, a case report of an Italian woman presenting with stigmata, the spontaneous manifestation of Jesus Christ’s crucifixion wounds, graced the pages of the international medical journal, Medicine. In the report, the authors, a group of Italian physicians, warned that as the woman had a “hysterical personality,” she could have easily been encouraged by family members to simulate her wounds for profit and attention. This paper offers a genealogy of the association of stigmata with the diagnosis of hysteria, tracing it from its origins in fin de siècle Paris to its appearance in contemporary medical literature with particular attention to how ‘religion’ may be constructed as ‘sick.’


title: Generalized Force Estimation using Machine Learning and Deep Learning with EMG and Motion Data

contributor:
Morin, Evelyn
Etemad, Ali
Electrical and Computer Engineering

subject:
EMG
force estimation
machine learning
deep learning
high density (HD) recording
dynamic contraction
isometric contraction
EMG-based force estimation

abstract:
Human movements are accomplished by muscle contractions, resulting in force exertion. Accurate estimation of the generated force is desired in many applications such as robotics, prosthesis control, and sports. The surface electromyogram (EMG) has been widely used for estimating force since the 1950s. However, EMG-force relationship is nonlinear and dynamically changing, and thus the development of an accurate model is a challenging problem for static, and especially dynamic contractions.
The objective of this research is to develop accurate force estimation models that are generalizable across individuals and experimental conditions, from static to fully dynamic cases. First, we study intra-subject force modelling during static conditions using fast orthogonal search and a novel channel selection method to reduce the dimensionality and correlation among recorded EMG channels. The results show a significant improvement in performance using the selected channels over the original dataset. To develop generalized models, classical machine learning is first used. Features from EMG are extracted, followed by feature selection using our proposed method, modified sequential feature selection. A bagged tree ensemble (BTE) is then used for force modelling. Next, deep learning is also explored, where convolutional neural networks (CNN) are developed for force estimation from EMG signals in both time and frequency domains. Results show that the CNN outperforms the BTE.
To accurately model exerted force under quasi-dynamic and dynamic contractions, where the EMG-force relationship is highly non-linear and complex, a CNN ensemble is proposed to learn the EMG-force relationships from multi-domain and multi-modal inputs. The proposed model uses individual deep CNNs to extract robust representations from EMG in time and frequency domains, and from kinematic information recorded by an inertial measurement unit (IMU). The learned representations are then fused at the feature level and fed to a neural network to estimate force. Our CNN ensemble method achieved highly accurate force estimation results for different experimental conditions in both intra- and inter-subject schemes. Our results indicate the superiority of our approach over other methods in the literature, and further validate the need for including EMG in both domains as well as kinematic information for accurate and generalized force estimation.

abstract: PhD


title: Experimental Modal Analysis of Business Jet Fuselage Tail Section Sub-Assemblies

contributor:
Mechefske, Chris
Mechanical and Materials Engineering

subject: Experimental Modal Analysis

abstract: Experimental modal testing is a technique through which the dynamic response characteristics of a system can be found. Parameters such as the natural frequencies and mode shapes of a system can be extracted through experimentation, and these results can be used to confirm computational models, and/or provide insights from which improvements can be made to improve dynamic response characteristics. This thesis provides an overview of experimental modal analysis performed on two half scale aircraft fuselage subassemblies using shaker excitation. Prior to experimentation, relevant literature was reviewed. This provided the necessary foundation of theory and prior experiments which helped to form the experimental methodology presented. This methodology including the construction of each structure, data acquisition parameters, and validity checks, is covered in detail. Linearity and repeatability checks were used to validate the testing methodology in accordance with ISO guidelines. Additional validity checks were performed to improve the test setup and further increase the level of confidence in the experimental results. The natural frequencies found were compared to the computational model, and where necessary, recommendations for future modelling improvements were made. In the case of the first sub-assembly, discrepancy in natural frequency for certain modes was reduced from 12 % to less than 2%. An acceptable level of correlation was found between experimental and computational results for the second fuselage structure, with a discrepancy of less than 10 % observed for most natural frequencies. Certain natural frequencies showed variance above 30 %, and potential reasons for this discrepancy are discussed. The experimental results also provided a basis of comparison for the mode shapes predicted in a computational model constructed by other researchers, acting to further validate computational results. With a detailed experimental methodology formed, and reliable experimental results produced, the project can now progress to the next phase which involves the construction and testing of a complete half scale tail section.

abstract: M.A.Sc.


title: CLASSIFICATION IN PARA SPORT: EXPLORING ATHLETES’ AND CLASSIFIERS’ EXPERIENCES WITH AND UNDERSTANDING OF CLASSIFICATION

contributor:
Latimer-Cheung, Amy Elizabeth
Kinesiology and Health Studies

subject:
Disability
Parasport
Classification
Hermeneutic Phenomenology
Paralympic
Experience

abstract: Classification is a defining feature of Para sport; however, little empirical evidence describes the experience of classification and how it can be improved. To date, the primary focus of research related to classification has been on the development of evidence-based classification procedures. Meanwhile, the limited literature which has focused on experiential aspects of classification has shown classification to be a potentially negative experience for athletes. As well, classifiers have been identified as important social actors within the Para sport context, yet no research has simultaneously examined athletes’ and classifiers’ experiences with classification. Therefore, the purpose of this study was to elucidate athletes’ and classifiers’ experiences with classification in Para sport. Semi-structured interviews exploring the experience of classification were conducted with 18 internationally classified Canadian athletes and an international sample of eight internationally certified classifiers. Hermeneutic phenomenological analysis was used to conceptualize athletes’ and classifiers’ classification experience. The results of this thesis show that athletes and classifiers experience classification in one of three ways: as a neutral experience, a negative experience, or a positive experience. Positive experiences were seen only in contrast to negative experiences. In the absence of a negative experience, athletes and classifiers experience classification neutrally. Athletes and classifiers construct their understandings of classification by reflecting on themselves (The Self), their interactions with one another (The Athlete-Classifier Interaction), and the classification system itself (The Classification System). Together, these findings provide novel insight into athletes’ and classifiers’ experiences with, and understanding of, classification and may inform for future interventions aimed at improving the experiences of athletes and classifiers.

abstract: PhD


title: Exploring The Role of Referential Context in Young Children's Cross-Situational Word Learning

contributor:
Sabbagh, Mark
Psychology

subject:
Cross-Situational Word Learning
Early Word Learning
Phonological Representations
Semantic Representations
Event-Related Potentials
Phonological Mapping Negativity
N400

abstract:
A fundamental question in early language acquisition concerns how young children learn new words despite often hearing them in visually complex and noisy environments. One potential mechanism that has emerged in recent years is "cross-situational" learning, which refers to young children's ability to track word-object co-occurrences across several ambiguous naming instances to learn new words. Often in cross-situational learning studies young children's learning is assessed using their eye-gaze and pointing behaviors in response to a forced-choice comprehension question (e.g., “can you point to the bosa?”). Although these testing procedures reveal that some learning has occurred because of the cross-situational exposure, they are not informative about the nature of the word representations underlying that learning.
In the current research, 4-year-olds first learned eight new word-object pairs in a cross-situational task and then had their event-related potentials (ERPs) recorded in a picture-word matching paradigm. In this task, pictures of objects were followed by words that were either associated with the object during training or with a different object. If participants learned the word-object associations, then when these were violated during test, I expected to see modulations of ERP components in early stages of word processing. If participants assigned meaning to the words, then I expected to see the early differences as well as differences on the later N400 component of the waveform, a negative peak at approximately 400 msec that indexes violation in meaning.
The ERP findings suggest that, (1) young children encoded the new word-object pairs and assigned meaning to the new words when they experienced familiar object labeling before training; (2) young children were less likely to assign meaning to the new words when they did not experience familiar object labeling before training; and (3) there is preliminary evidence that while not all children learned well without a familiarization routine, those that did showed evidence of forming semantic representation for the new word meanings. I discuss the implications of these findings for the study of the cross-situational learning and for broader theories of early word learning.

abstract: PhD


title: An Exploratory Study of Novel Measures to Capture Situational Expressive Suppression

contributor:
Hollenstein, Tom
Psychology

subject:
Expressive suppression
Social functioning
Relationship quality
Naturalistic observation
Measurement development

abstract:
Expressive suppression is widely believed to be a maladaptive emotion regulation strategy due to
its association with poor social functioning. Nonetheless, controlling when and how to express
emotions is also the hallmark of competent emotion regulation. However, we do not have a clear
understanding of how spontaneously-occurring expressive suppression use during social
interactions impacts social functioning. Therefore, the current study tested three novel measures
of situational expressive suppression as predictors of relationship quality. Adolescents (N = 184)
and their mothers engaged in an emotional discussion in the lab. Adolescents’ expressive
suppression was measured through self-report, observation, and an interaction between feelings
and expression (i.e., high feelings and low expression indicating suppression), to predict
mothers’ ratings of relationship closeness. The observation and interaction approaches predicted
lower relationship quality. However, the self-report measures did not predict relationship quality,
and there was minimal concordance among all novel measures. I discuss the possibility of
expressive suppression being observable and possible future directions to further develop the
novel measures to better capture expressive suppression.

abstract: M.Sc.


title: Assembling Zibi: How Profits, Property, and Policing Undermined Algonquin Urban Land Reclamation at Asinabka in Canada’s National Capital Region

contributor:
Castleden, Heather Evelyn
Geography and Planning

subject:
Settler Colonialism
Racial Capitalism
Policing
Urbanization
Settler Colonial Urbanism
Private Property
Algonquin
Zibi

abstract: The product of three years of solidarity work with a group of Algonquin land defenders and settler allies struggling to reclaim Asinabka, an Algonquin sacred place in the heart of Canada’s National Capital Region, this dissertation examines how settler colonialism’s urban strategies are (re)organizing in response to the material and discursive demands of urban Indigenous land reclamations. A collection of islands and waterfalls in the Kitchissippi (Ottawa River), located between downtown Ottawa, Ontario, and Gatineau, Quebec, the current Algonquin struggle to reclaim Asinabka began in the early 1990s. In 2013, despite fierce Algonquin opposition, corporate real estate developers purchased derelict industrial properties on the islands and announced plans to construct ‘Zibi’, a $1.5 billion high-density mixed-used eco-community. Drawing on participant action research, access to information requests, archival research, and key informant interviews, the research tracks the strategies and practices mobilized by a bloc of government officials, municipal bureaucrats, police agencies and real estate developers, to undermine the land reclamation movement. Building on literatures in critical urban studies, settler colonial studies, and racial capitalism, this dissertation examined three facets through which Asinabka was secured as a white possession: a) it tracks the recursive histories that produced the current distribution of ownership and power at Asinabka and how those histories were recuperated in the present to enact ongoing dispossession; b) it interrogates how the spatialities of race, property, and jurisdiction were mobilized in the present to fortify white possession at/of Asinabka against the demands of the land reclamation; and c) it elucidates how police agencies used a litany of minor interventions to systematically deny sustenance to radical elements of the land defence by modulating the eventfulness of organizing efforts. Though ultimately the story of a defeat, it does not end there. In analyzing what land defenders and allies were up against, I offer notions of recursion, fortification, and modulating eventfulness as a suite of grounded activist hermeneutics designed to crystalize, and thus help strategize against, ongoing racial colonial violence concealed by the white setter state’s pivot to the politics of liberal recognition and reconciliation. Yes, we lost. Next time we lose better.

abstract: PhD


title: A Rose in the Forgotten Paradise - The Heteronymical Anonymity of João Delgado: towards political solidarity among the different selves.

contributor:
Naaman, Dorit
Cultural Studies

subject:
heteronyms
cultural politics
contemporary art
independent art practices
authorship in contemporary art
Israeli contemporary art
Jerusalem Visual Arts
authorship and collectivity

abstract: The following thesis is about the work of the Sala-Manca group, a group of two Argentinean born artists based in Jerusalem, Israel, one of whom is the author of this thesis.  Over the past twenty years the group has developed projects that are characterized by cross cultural and intertextual references, use of fiction, translation of “absent originals” and the use of heteronyms (fictitious persona) and heteronymic platforms. This thesis considers the place of the individual in relation to the collective; the place of the collective in the construction and deconstruction of the I; and the political implications both in the artistic text and at the authorship level.  I approach their/our work through the concepts of multiplicity, plurality, collectivity and collaboration combining contemporary theories dealing with the implications of the split self (Deleuze and Guattari's schizoanalysis), Nancy’s singular-plural and Glissant’s multiplicity. I argue that the search for diffused authorship and multiplicity is a diasporic point of departure for the artists to deal with Israeli politics and reality. Moreover, the thesis seeks to examine the boundaries of the search for de-centered authorship. The thesis is interdisciplinary and combines methodologies from art history, cultural studies, philosophy, literary studies, ethnography and performance studies.

abstract: M.A.


title: Finding Failures in Real-Time Systems Using Realistic Model Scheduling

contributor:
Dean, Thomas
Alalfi, Manar
Electrical and Computer Engineering

subject:
Scheduling
AUTOSAR
Real-Time System
Simulink
Mutation Operator
Model-Based Mutation Testing
Model-Based Testing
Mutation Testing

abstract:
Model-Driven Engineering (MDE) has developed into an increasingly accepted and established research field. With the widespread use of MDE development methods, the need for analysis of models becomes imperative. One form of analysis is temporal correctness. Temporal correctness depends on timing assumptions for each functional model. The functional models usually are based on a Synchronous Reactive (SR) execution paradigm, and the model executes simultaneously and instantaneously. It assumes the model behaviors are completed in approximately zero execution time, while the implementation execution requires a finite execution time, which may cause a failure.

This thesis extends the Matlab/Simulink (ML/SL) environment to model the real-time system's timing properties. We develop a tool SimSched, which can schedule  ML/SL models more realistically so that ML/SL simulation can reflect the real-time execution on the target platform with non-zero simulation times. It enables a more realistic analysis during model development at the early stage to reduce the software maintenance cost. SimSched supports  AUTOSAR (AUTomotive Open System ARchitecture), an open industry standard for the automotive sector. To address AUTOSAR's lack of support for modeling behaviors of runnables, languages such as ML/SL are employed. SimSched uses a model transformation to integrate scheduling into the model to validate the real-time context during a simulation.

To evaluate SimSched, we turn to mutation testing. Model-based mutation testing (MBMT) is a specific variant of model testing. It generates faulty versions of a model using mutation operators to evaluate and improve test cases. Mutation testing is an effective way to ensure software correctness and has been applied to various application areas. Simulink is a vital modeling language for real-time systems. This thesis introduces ML/SL model mutation analysis to improve Model-in-the-loop(MIL) testing. We propose a set of Simulink mutation operators based on  AUTOSAR, which reflects the temporal correctness when a Simulink model is mapped to Operating System tasks. We implement a mutation framework that generates mutants for implicit clock Simulink models. We demonstrate how this framework generates mutants to reveal task interference issues in the simulation.

abstract: PhD


title: Mechanisms of particle-liquid interaction in high-mobility debris ﬂows

contributor:
Take, William Andrew
Civil Engineering

subject:
debris flows
granular temperature
granular flows
transparent soil
air entry
collisional-frictional model
travel angle
landslide mobility
excess pore pressure
Particle Tracking Velocimetry
Particle Image Velocimetry

abstract: Debris flows are a category of fast-moving landslides with the potential for exceptionally long travel distance. The transition from a geomaterial to a viscous fluid has garnered attention from many fields of research, with this coupled behaviour viewed from the fluid mechanics, geotechnical effective stress, and granular physics perspectives. The presence of liquid in the pore space leads to complex mechanisms of interaction with the solid particles, including buoyancy, drag, and the potential for pore pressure exceeding hydrostatic conditions. These mechanisms may lead to significant scaling effects with flow thickness, limiting the applicability of empirical scaling relationships. It is known that the addition of liquid to a granular flow reduces equivalent flow resistance over the dry case. However, is is unclear whether the concept of reduced frictional resistance through the concept of effective stress is alone sufficient to explain the increased mobility of fluid saturated flows. Research is presented towards quantifying the collisional and frictional components of the flow regimes in dry and saturated granular flows. Advances were made in measuring granular temperature, an index of collisional behaviour in flows, through image analysis. Experiments were conducted using the same monodisperse (uniform particle size) material in a large laboratory flume and a Vertically Rotating Flume. The results suggest a preference for wet flows to form collisional shear bands at depth and that elevated pore pressure levels need not be present for a marked decrease in flow resistance to occur. Additionally, a transparent soil-oil mixture was used to visually illustrate dilative behaviour upon initial shearing and the potential for suction generation. The results demonstrate the partitioning of stress between the collisional and frictional regimes within dry and saturated granular flows and indicate additional potential mechanisms leading to high-mobility debris flows. It is anticipated that the advances in granular temperature measurement will be beneficial for experimental validation of various Extended Kinetic Theories and that the results of the flume and rotating drum trials will accelerate the inclusion of collisional behaviour within material models for debris flows.

abstract: PhD


title: From the Physical Body to the Body Social: The Development of Enlightenment French Materialism

contributor:
Mah, Harold
History

subject:
French Enlightenment
Materialism
Nature
The Body
d'Holbach
Diderot
La Mettrie
Montesquieu
Sensationism

abstract:
This thesis examines the development of materialism in the French Enlightenment from 1745 to 1789. As a relatively new intellectual category in the eighteenth century, materialism was systematized after the 1740s in France and endorsed a monistic ontology and cosmology of matter and motion; at the same time, the materialists were opponents of Christianity and the Church, which gave rise to the denunciations from the religious and governmental authorities and led to the moralization of the originally amoral materialist principles.

My main argument is that eighteenth-century French materialism consisted of a series of efforts to base the physical and the human worlds on secular theories of nature—in essence, on the autonomy of the human body, or the corporeality of human beings. These efforts were heterogeneous and caused a crisis of ideas about the relationship between nature and order, which undercut the theory of the autonomy of the physical body and led to the arrival of the body social. Consequently, the plan of nature gave way to the plan of society. I discuss the thought of major materialists like La Mettrie, Diderot, Helvétius, and d’Holbach, and show how French materialism gradually changed its original course. Besides, one chapter is devoted to Montesquieu. Although not a materialist, his thought is important for understanding the peculiar position of French materialism that was torn between nature and order.

abstract: PhD


title: Solar ultraviolet radiation and colorectal cancer risk in Canada

contributor:
King, Will
Public Health Sciences

subject:
Epidemiology
Colorectal cancer
Ultraviolet radiation
Risk factor

abstract:
Background: Colorectal cancer (CRC) is the third most common cancer in Canada with an estimated 26,000 new cases in 2020. Novel modifiable risk factors such as solar ultraviolet radiation (UVR) warrant research to promote prevention of avoidable cases. Previous studies examining the relationship between solar UVR and CRC risk show inconsistent results. This thesis examined this potential relationship using nationally collected data to provide a unique Canadian perspective. Differences in effect between colon and rectal as cancer sites are examined in addition to interactions with other variables of interest. A protective U-shaped relationship is hypothesized with the lowest risk at moderate exposure levels.

Methods: Self-reported questionnaire data from three cohorts within the Canadian Partnership for Tomorrow project provided sun exposure and covariate data. Cohorts were linked to cancer registries or administrative data to identify cancer cases. Cox proportional hazard models estimated the hazard ratios for time spent in sun as well as ambient UVR in relation to CRC risk. Hazard ratios were also estimated separately for colon and rectal cancers. Interactions by ambient UVR, sex, vitamin D intake, and skin tone were explored.

Results: Neither time spent in sun nor ambient UVR had a statistically significant association with CRC risk. No association was found with rectal or colon cancer when examined individually. No significant interactions between time spent in sun and sex, ambient UVR, and vitamin D were observed.

Conclusion: Overall, results do not support a relationship between exposure to UVR in Canada and risk for CRC. This project adds to the small body of literature by examining this relationship in a Canadian setting and with two measures of solar UVR exposure. Investigation into interactions also provide insight on differing effects. Future research should expand upon this study with greater variation in ambient UVR and a more comprehensive timeline of UVR exposure to understand potential induction periods.

abstract: M.Sc.


title: The Master Plan: Power, Design and the Making of a Place.

subject: film, architecture, Jerusalem, Israel, Palestine

abstract:
This thesis is a personal attempt to tell the story of architecture in modern Jerusalem in the
aftermath of the forced 1967 unification of the city. From the perspective of an IsraeliJerusalemite born after the 1967 war, in which Israel conquered the eastern part of the city from
Jordan, it explores how the city’s architecture has affected notions of self, ideology, and
belonging. This thesis traces the development, both in content and in form, of a documentary
film that addresses the power architecture has in defining a national sense of belonging and
appropriating space. This Research-Creation project investigates different locations and
architects and includes a personal perspective on four different spaces in the city, in an attempt to
understand how such a complex story about appropriation can be told.

abstract: M.A.


title: PLASTICITY AND EVOLUTIONARY POTENTIAL OF ALLIARIA PETIOLATA LIFE HISTORY AND LEAF CHEMISTRY TRAITS IN DIFFERENT COMPETITIVE ENVIRONMENTS

contributor:
Colautti, Robert
Biology

subject:
Allelopathy
Adaptive Evolution
Plant Competition
Secondary Metabolites
Species Invasions

abstract: Alliaria petiolata is an invasive biennial herb in North America where it has detrimental impacts on flora and fauna. Allelopathy, the chemical inhibition of plant competitors, is one explanation for why A. petiolata is more successful in North America than in Eurasia, where it is native. There is strong laboratory evidence that A. petiolata is allelopathic, and recent evidence has suggested that natural selection acts on allelopathic compounds (i.e., allelochemicals). If selection is acting on allelochemicals, allelopathy should influence survival and reproduction; however, there is not strong evidence of this in field settings. To shed light on this discrepancy, I measured phenotypic selection, plasticity and heritability of putative allelochemicals and life history traits to determine if there is selection on allelochemicals, if allelochemicals can respond to selection, and if selection is due to a direct effect of allelopathy, or due to selection acting on a correlated trait. Using families from 23 A. petiolata populations, I measured glucosinolate, flavonoid and chlorophyll A expression in A. petiolata leaf tissue to estimate selection on these traits in inter- and intraspecific competition and without competition. A separate experiment was also conducted to test the effect of soil nutrients on glucosinolate, flavonoid and chlorophyll A plasticity using 3 different A. petiolata families. I found that A. petiolata exhibited strong plastic responses to both fertilizer application and competition, but most traits exhibited very low heritability. I also found that while selection appeared to act on glucosinolate expression during interspecific competition, there is more evidence to suggest that glucosinolate expression was under indirect selection due to direct selection acting on the correlated trait, chlorophyll A in response to light limitation. There was genetic variation for glucosinolate expression, but it was mostly manifested in the ratio of glucosinolate: chlorophyll A expression, therefore, the heritability of glucosinolate expression is likely to vary among environments and to be higher in nutrient-rich environments. These results highlight the need to account for plasticity and heritability and measure other important traits to account for indirect selection when assessing evolutionary potential.

abstract: M.Sc.


title: ProCam Calibration using Single Pose of 2D Planar Target

contributor:
Greenspan, Michael
Electrical and Computer Engineering

subject: Procam calibration optimization stereovision homography

abstract:
This thesis presents a simple and user friendly method for calibrating a procam
system from a single pose of a 2D planar target. The camera intrinsic parameters,
projector intrinsic parameters, procam system's extrinsic parameters and the distortion
coe cients of the camera are returned using this method.
Two sets of experiments were conducted: simulation experiments and real data
experiments. The purpose of the simulation experiments were to test which poses of
a camera and projector relative to a chessboard produce accurate calibration parameters.
Several poses of a chessboard were imaged and used to calibrate a real procam
system using the technique presented in this thesis and a Zhang-based method was
used as the ground truth. The results of the real data experiments are congruent
with the simulation experiments; accurate camera intrinsic parameters are returned
when absolute sum of the X-axis and Y-axis rotation of the chessboard relative to the
camera is greater than 20 degrees and accurate projector intrinsic parameters when
the absolute value of the Y-axis rotation of the chessboard relative to the projector is
greater than 10 degrees. When the conditions for valid camera and projector intrinsic
parameters are met then accurate extrinsic parameters are returned as well.

abstract: M.A.Sc.


title: Novel Structures and Materials for Broadband Antennas

contributor:
Saavedra, Carlos
Electrical and Computer Engineering

subject:
Broadband Antennas
Reconfigurable Antennas
Millimeter-wave Antennas
Dielectric Spectroscopy
Flexible Substrates
3D Printed Substrates
Fluidically-Tuned Antennas
Material Characterization

abstract: Presented in this thesis are advancements made in the fields of broadband antennas, reconfigurable antennas and emerging materials in applied electromagnetics. Firstly, the investigation of a millimeter-wave log-periodic toothed antenna (LPTA) is shown. The design features a novel integrated planar feed structure which provides an extreme broadband input match. Simulation is carried out using a finite-element code (Ansys HFSS) to demonstrate operation from 22.8 GHz to 44.0 GHz with a peak realized gain of 7.48 dBi. Secondly, the investigation of an aperture-coupled liquid metal dipole antenna is presented to demonstrate continuous frequency reconfigurability over a 21% tuning bandwidth. A novel aperture-coupling feed structure with reduced back radiation is explored as a means to excite the liquid metal dipoles without requiring physical contact. A prototype is fabricated and measured where an input match of S11<-13 dB and peak gain of 3.99 +/- 0.51 dBi is observed over the tunable range. Thirdly, the broadband dielectric spectroscopy of emerging novel microelectronic materials is presented. Materials studied are those seeing use in microfluidic electronics, wearable electronics, and 3D printed electromagnetic structures. Complex permittivity is measured using commercial coaxial probes and novel analytic Cole-Cole models are produced through a non-linear least squares fitting routine on experimental data.

abstract: M.A.Sc.


title: Ergodicity Conditions For Controlled Stochastic Non-Linear Systems Under Information Constraints

contributor:
Yuksel, Serdar
Kawan, Christoph
Mathematics and Statistics

subject:
Stochastic Control
Stochastic Dynamical Systems
Control Under Communication Constraints
Stochastic Stabilization

abstract: In this thesis we study the problem of stabilizing a controlled discrete time non-linear stochastic dynamical system, subject to information constraints. Consider such a system, controlled over a (possibly noisy) communication channel. An important problem is to determine the minimum channel capacity required to render the state process stable via a causal coding and control policy. In this thesis we consider this problem for the stability notion of asymptotic ergodicity of the state process, and prove lower bounds on the channel capacity necessary to achieve it. Under mild technical assumptions, we obtain that the necessary channel capacity is lower bounded by the log-determinant of the linearization, double-averaged over the state and noise space. We prove this bound by introducing a modified version of invariance entropy and utilizing the almost sure convergence of sample paths guaranteed by the pointwise ergodic theorem. The fundamental bounds obtained generalize well-known formulas for linear systems, and are in some cases more refined than those obtained for non-linear systems via information-theoretic methods.

abstract: M.Sc.


title: Development of Low-Energy Calibration Techniques for SuperCDMS using LEDs Operated at Cryogenic Temperatures

contributor: Physics, Engineering Physics and Astronomy

subject:
SuperCDMS
Dark Matter
Particle Physics
Cryogenics
Calibration techniques
Cryogenic detectors
IR photon

abstract:
The desire to unveil the mystery of dark matter which, according to compelling astrophysical and cosmological evidence, constitutes about 85% of the matter in the Universe, drives physicists to continuously develop their tools and search methodologies. There are several proposed candidates for new particles among which the Weakly Interacting Massive particle (WIMP) is considered the most propitious.

The SuperCDMS SNOLAB experiment is a direct dark matter (DM) detection experiment. It is expected to start taking science data by the beginning of the year 2023. The plan is to start the operations with a total payload of ~30 kg of Ge and Si detectors, situated in a well-shielded cryostat with ~15 mK at the coldest thermal stage. The experiment aims to probe DM with masses down to 0.3 GeV (0.5 MeV) through nuclear (electron) scattering. To accomplish this, detectors have to have energy thresholds of a few eV.

The Cryogenic Underground TEst facility (CUTE) is currently the underground facility equipped to operate the future SuperCDMS detectors. Since summer 2019, the facility has operated a variety of detectors to identify, quantify, and mitigate its noise sources and investigate its potential for dark matter search while waiting for SuperCDMS to be completed. In this thesis, I discuss key contributions to setting up and commissioning the facility in a timely manner. I also summarize the major tests and findings.

The low energy reach of the new SuperCDMS detectors brings the need for new calibration methods. We propose two different methods that use LEDs operated next to the detectors. This has initiated the study of LED properties at low temperatures. One of the suggested methods has been shown to be viable, and preliminary tests for the other method have shown promising results. Finally, I show the possibility of operating LEDs in the proximity of an eV-sensitive detector without impacting its performance.

abstract: PhD


title: BIOREACTOR-BASED STRATEGY FOR DIFFERENTIATION OF ADIPOSE-DERIVED STEM CELLS TOWARDS NUCLEUS PULPOSUS CELLS

contributor:
Amsden, Brian G.
Chemical Engineering

subject:
BIOREACTOR-BASED STRATEGY
DIFFERENTIATION
ADIPOSE-DERIVED STEM CELLS
NUCLEUS PULPOSUS CELLS

abstract:
Intervertebral disc degeneration (IVDD) experienced by ~80% of worldwide population initiates in the nucleus pulposus (NP). This research aimed to establish a validated method for obtaining NP-like cells from adipose-derived stem cells (ASCs) for NP regeneration, through optimizing culture conditions inside a bioreactor. Five conditions were proposed to be tested in a full 25-factorial design, based on their physiological values: loading amplitude (0.8 vs. 0.2 MPa), strain frequency (1 vs. 0.25 Hz), oxygen tension (20 vs. 2%), presence of NP-specific extracellular-matrix-particles (DNPT) and immortalized human chordoma U-CH1 cells.

Human ASCs encapsulated within reversible Ca-alginate hydrogels were subjected to these factors within a commercial bioreactor obtained from CellScale Biomaterials Testing Inc. Firstly, the encapsulation and cell retrieval processes were optimized, by testing different protocols on crosslinking and decrosslinking of Ca-alginate gels, the centrifugation step in cell retrieval from the gels, and purification of the Na-alginate solution. The best cell recovery obtained following de-crosslinking the gels was 66.5 ± 20.8 % with a cell viability of 69.1 ± 15.0 % for human ASCs. In addition, a 2-time charcoal purification of Na-alginate, and a seeding density of 1.7 x 106 cells/mL with 3 gels to be harvested generated sufficient high quality RNA samples from the ASCs for qPCR analyses. Thirdly, the bioreactor design was optimized with respect to valves used, flow pattern within the wells, and flow conditions that allowed for medium perfusion between loading cycles for nutrient and oxygen exchange, and also for re-crosslinking of Ca-alginate gels to maintain their integrity, while withstanding up to 0.9 MPa with no medium leakage during loading. Lastly, the flow rate (FR) through the bioreactor was also optimized with respect to cell viability. The highest cell viability of 52.1 ± 6.1 % was obtained at no perfusion, and best cell viability of 16.1 ± 3.7 % under a FR of 1 mL/min. Overall, this research provides the first few steps in the design of a bioreactor-based strategy for ASC differentiation towards NP cells.

abstract: M.A.Sc.


title: Investigating the Regulation of Audit Quality in Canada: Complexity, Emotions, and Expertise

contributor:
Malsch, Bertrand
Guénin, Henri
Business

subject:
Audit Committee
Audit Partner
Audit Quality
Partner Prototype
Quality Expert
Regulation
Style of Oversight

abstract:
I investigate the impact of regulation around audit quality in Canada on the work and perceptions of the stakeholders directly affected by these rules. More specifically, I examine auditors’ and audit committee (AC) members’ respective experience with: 1) National Instrument 52-108, which created the Canadian Public Accountability Board (CPAB) responsible for independently overseeing and inspecting auditors of Canadian reporting issuers; and 2) National Instrument 52-110, which notably sets requirements for the responsibilities of ACs as well as for the level of requisite expertise of AC members.

Based on 48 interviews conducted with audit managers, audit partners, and AC members of Canadian reporting issuers, my analysis reveals the empirical depth of the Canadian audit regulation by shedding light on the actors, the processes, and the tensions embedded in the changes made to the environment of public companies. In my first study, I build on institutional theory to examine both the pressure brought by independent inspections and the changes implemented by audit firms in response to this added pressure. In my second study, I draw on Bourdieu’s scholarship to assess the effects of regulation and inspections on auditors’ experience of partnership and career trajectories. In my third study, I use a social constructivist approach to knowledge to analyze the way AC members perceive and enact their expert role in practice.

My findings show that regulation has brought its share of complexity at the institutional, organizational, and individual levels. The new regulations have shaken the field by modifying the distribution of expert authority and status in the financial reporting system, which triggers a wide variety of emotional reactions. In this major overhaul, CPAB regulators have gained influence while audit partners have experienced a significant disjunction because of both regulators’ scrutiny and the renewed focus on the technical aspects of auditing. For their part, AC members have gained in expert status but struggle with uniformly embodying their expert role. Hence, AC members adopt different styles of oversight that do not require the same effort, knowledge, and focus, resulting in heterogeneous governance practices on ACs.

abstract: PhD


title: Maternal Attitudes and Infant/Child Temperament: Questionnaire Assessment and Applied Intervention

contributor:
Kuhlmeier, Valerie
Psychology

subject: Temperament Parenting Self-Efficacy Intervention Questionnaire

abstract:
The importance of the parent-child relationship is reflected in a great deal of research, theory, and public health programs. The complexity of these relationships creates methodological challenges for researchers and clinicians alike. One strong predictor of positive parenting behavior is Parent Self-Efficacy (PSE): the parent’s own confidence in their ability to successfully parent their child. It is far more practical to assess PSE, which can be measured by questionnaire, than to observe and assess parent-child interactions directly, leading many professionals to select PSE as an outcome assessment for parenting programs.
Child temperament is another essential consideration for parenting, as temperamentally vulnerable children are more likely to elicit negative interactions and are also more adversely affected by them (e.g., Lorber & Egeland, 2011; Slagt et al., 2016). Limited resources often preclude the use of observational measures of temperament as well, so many professionals rely on parent report via freely available questionnaires (e.g., Putnam et al., 2006, 2013).
Given widespread reliance on these questionnaire measures, consideration of psychometric characteristics, applicability of items, and other potential influences on parents’ responses is crucial. Indeed, substantial discrepancies between parental report and laboratory observational measures of temperament have been documented (e.g., Seifer et al., 2004).
In this dissertation, I investigate methodological issues and program effectiveness in the field of temperament and parenting. In Chapter 1, I present theory and research on the function and measurement of parental attitudes and child temperament. In Chapter 2, I investigate the underlying factor structure of measures of maternal attitude and child temperament. Findings suggest the primary importance of child shyness in mothers’ response patterns. In Chapters 3 and 4 I present results of a parenting program evaluation using these questionnaire measures. In Chapter 5, I use multi-method assessment of child temperament to determine whether maternal attitudes may account for discrepancies between observational and questionnaire-based temperament scores. These analyses show unexpected associations among measures and substantial discordance between measures of each temperament characteristic, which were not explained by maternal attitudes. I discuss these results in Chapter 6, including recommendations for further research and public health initiatives.

abstract: PhD


title: MEASUREMENT OF UN PEACEKEEPER-PERPETRATED SEXUAL  EXPLOITATION/ABUSE AND THE RELATED STIGMATIZATION OF WOMEN AND GIRLS IN THE DEMOCRATIC REPUBLIC OF CONGO

contributor:
Bartels, Susan
Stuart, Heather
Public Health Sciences

subject:
sexual exploitation
sexual abuse
stigma
UN peacekeepers
Democratic Republic of Congo
violence against women

abstract:
Background: UN peacekeeper-perpetrated sexual exploitation and abuse (SEA) is an international concern with reported allegations across 32 peace support operations. Stigma attributed to broader sexual and gender-based violence is well documented in the literature, however little is known about the relationship between UN-peacekeeper perpetrated SEA and stigma in the Democratic Republic of Congo (DRC). As current binary measures of SEA disregard its complexity in peacekeeping settings, an index is proposed as an alternative measure.
Methods: The objectives of this study were to construct an index to quantify the level of SEA exposure experienced by women/girls in the DRC and to examine how SEA exposure was related to community perceptions of Congolese women/girl’s social status and institutional support. Using mixed-methods DRC survey data (n=2867), SEA indicators were identified using a combination of qualitative and quantitative survey variables. Two Poisson regression models with robust variance estimation were constructed to quantify the associations between SEA exposure and stigma by relative risk. Demographic variables were assessed for confounding and narrator’s sex was assessed for effect modification.
Results: Eight indicators of SEA exposure were identified: six derived from the thematic analysis and two from the existing survey variables. A positive relationship was demonstrated between the level of exposure and diminished social status with women/girls experiencing moderate levels of SEA having the greatest risk of public stigmatization (RR: 1.94; CI: 1.66 – 2.26). Similarly, a positive relationship between SEA exposure and inadequate institutional support was shown for female narrators wherein women/girls highly exposed to SEA were 6.53 times as likely to receive inadequate support (RR: 6.53; CI: 3.63, 11.73). This contrasted with male narrators for whom there was no significant association.
Conclusions: With further development, this index may offer a more nuanced perspective of peacekeeper-perpetrated SEA to inform SEA prevention and intervention efforts. The high risk of public and structural stigmatization in women/girls who were highly exposed to SEA indicates the importance of considering exposure levels when conceptualizing SEA consequences in peacekeeping contexts. The frequency of both public and structural stigma, and varying perceptions by sex, demonstrates the need for a multi-faceted approach for stigma reduction.

abstract: M.Sc.


title: Drag and Mixing from Forced Mixing Nozzles on Turbofan Engines

contributor:
Birk, Albrecht Michael
Mechanical and Materials Engineering

subject:
turbofan
mixing
thrust
drag
lobed
scalloped
nozzle
CFD
RANS
wind tunnel
seven-hole probe
high bypass ratio
unmixed exhaust
engine model

abstract: An opportunity was identified for the suppression of unmixed high bypass ratio turbofan engine thermal signatures via forced mixing nozzles to increase mission safety. A feasibility study was proposed quantifying potential temperature and pressure uniformity factor enhancement at the expense of net thrust and added weight. An in-depth RANS-CFD parametric study of forced mixers on a full-scale target engine was warranted by gaps in the literature. First, a low-Mach experiment was designed to study the impact of fan generated swirl on mixing nozzle performance. Successful mixer design through reproducible methods observed no flow separation and converted angular momentum into enhanced thrust through the lobe passages. Normal and streamwise vortex features were quantified. Increased entrainment of mass flow accompanying greater than freestream levels of normal vorticity correlated best with total pressure uniformity index. Second, lack of full-scale engine geometry and operating conditions forced the creation of a quasi-2D design-point engine model of the PW2040 (F117-PW-100). An axisymmetrical geometry of the low-pressure system, derived from the model, was simulated at take-off and top-of-climb conditions using core intake and outlet modeled properties and a fan-stator source term user defined function. Taking the RANS-CFD results as baseline, mixer performance metrics could be readily compared. Finally, a full-scale lobed mixer parametric study, featuring 12 well-defined geometries, was performed by matching the core choke point. The effect of lobe number, length, height, crest/keel ratio, scalloping, and swirl was investigated on vorticity, drag composition, thrust, and mixing indices at top-of-climb. A direct tradeoff between net thrust and vorticity levels was observed with changes in mixer length for constant lobe height. Designs could enhance wake uniformity up to 25% at a cost of 5% in net thrust. Optimization would improve this result. Detailed engine maps could allow for the reduction in back pressure associated with enhanced mixing and jet perimeter to be propagated through the core engine.  A vast quantity of literature, experimental methods, numerical setup, practical codes/scripts, and standard operating procedures were included to support the work and provide guidance and inspiration for future researchers.

abstract: PhD


title: EXAMINATION OF CBP/P300/AKT, NF-ΚB AND STAT3 SIGNALING FOLLOWING IN UTERO VALPROIC ACID EXPOSURE IN CD-1 MOUSE EMBRYOS WITH  NEURAL TUBE DEFECTS

contributor:
Winn, Louise M.
Biomedical and Molecular Sciences

subject:
Valproic acid
Neural tube defects
Teratogenesis
CD-1 mouse embryos

abstract: Valproic acid (VPA), an antiepileptic drug and effective treatment for mood disorders is teratogenic with an increased risk of congenital malformations including neural tube defects (NTDs) following in utero exposure. The mechanisms of the VPA-induced NTDs are not yet fully understood. Studies in this thesis investigated the role of three key signaling pathways, the Cbp/p300/Akt, the nuclear factor kappa B (NF-κB), and the signal transducer and activator of transcription3 (Stat3) in VPA-induced NTDs using the CD-1 mouse model. Following in utero exposure to a teratogenic dose of VPA (400 mg/kg) during the critical period of the neural tube (NT) closure at gestational day (GD)9, mouse embryos were harvested on GD9, GD10, and GD13. At GD9 and GD10 whole embryos were analyzed, while at GD13, the heads of control, non-exencephalic, and exencephalic embryos were used for analysis. The first study showed that Cbp, p300, and Akt mRNA expression was downregulated, Cbp/p300 protein levels remained unchanged, while Akt protein levels were upregulated in GD9 embryos. The second study investigated the effects of VPA exposure on the key components of the NF-κB signaling pathway including p65, p50, and Pim-1. A decrease was observed in p65, p105/p50, and Pim-1 mRNA expression in GD9 embryos. Furthermore, upregulated p65 and downregulated p50 protein levels were noted in GD13 embryos. The nuclear levels of total p65 and p50 protein levels remained unchanged in VPA-exposed non-exencephalic and exencephalic GD13 nuclear extracts from embryonic heads. The third study characterized the effects of VPA on the transcription factor Stat3.  Stat3 mRNA expression remained stable while total Stat3 protein levels were increased in GD9 embryos and GD13 embryonic heads. In contrast, phosphorylated Stat3 protein levels were downregulated in GD9 embryos with an overall trend of downregulation in the GD10 and GD13 groups. In conclusion, the studies described in this thesis indicate that the perturbations in the Cbp/p300/Akt, NF-κB, and Stat3 signaling pathways following in utero VPA exposure might contribute towards VPA-induced NTDs.

abstract: PhD


title: USE OF PATTERNED (SUPER) HYDROPHOBIC SURFACES IN SAMPLE PREPARATION

contributor:
Oleschuk, Richard
Chemistry

subject:
Digital Microfluidics
Superhydrophobic Surface
Sliding Angle
Sample Fractionation
Superparamagnetic particles (PMPs)
3D Printing
LC-Archiving
HDMs

abstract:
Digital microfluidics (DMF) is an emerging liquid-handling technology that enables the manipulation of small, discrete droplets (picoliters to microliters) in a precise and reproducible manner. The important applications of DMF involve droplet dispensing, moving, splitting and mixing contents within a droplet. Superhydrophobic (SH) surfaces are used in DMF for facilitating magnetic actuation of droplets and formation of microarrays. A surface is considered superhydrophobic if a water droplet displays both a water contact angle (θCA) >150◦, and a sliding angle (SA) <10◦. SH surfaces provide low frictional forces between a liquid droplet and the surface itself allowing for actuation using minimal force. Magnetic actuation uses an external magnetic field to manipulate droplets containing magnetisable particles (MPs).
This thesis focuses on the actuation of organic and aqueous droplets on patterned (Super) hydrophobic surfaces. Different commercial coatings used in this study are Ultra-Ever Dry™, Never wet™ and Aculon®. Different surfaces can be patterned to higher surface energy patches called surface energy traps (SETs). Droplets can be pinned to the SETs and dewetted from the SETs. We utilize the contrasting behavior of patterned surfaces to quantitatively determine the ethanol in beer samples. The application of functionalized superparamagnetic particles (PMPs) in combination with magnetic separation techniques has been used for the fractionation of complex proteolytic digest of lysozyme. Droplet kinematic parameters are explored (e.g., volume, size of the SETs, particle concentrations, etc.). Furthermore, we utilize the patterned omniphobic surface Aculon® in combination with the magnetic actuation technique to extract a peptide (bradykinin) from artificial saliva. The fifth chapter of the thesis demonstrates the proof of principle of liquid chromatography (LC) archiving using high-density microarrays (HDMs) platform.

abstract: PhD


title: Information Transmission over Two-Way Networks

contributor:
Alajaji, Fady
Linder, Támas
Mathematics and Statistics

subject:
two-way channels
joint source-channel coding
capacity region
channel symmetry
multiple access and broadcast channels
channels with memory
adaptive coding
network information theory
lossy transmission
hybrid analog and digital coding
superposition coding

abstract:
Shannon's two-way channels (TWCs) allow two terminals to exchange data streams in a full-duplex manner and enable interactive adaptive coding to improve transmission reliability. However, TWCs are often used in conjunction with orthogonal multiplexing to mitigate the interference incurred from simultaneous transmissions over a shared channel. To date, TWCs with non-orthogonal multiplexing are still not fully explored. This thesis examines channel capacity problems for TWCs and identifies coding methods to facilitate and enhance two-way simultaneous transmission.

We first make use of channel symmetry properties to determine the capacity region of three types of two-way networks: (a) two-terminal discrete-memoryless TWCs (DM-TWCs), (b) two-terminal TWCs with memory, and (c) three-terminal multiaccess/degraded broadcast DM-TWCs. For each network, symmetry conditions under which a Shannon-type random coding inner bound (under independent non-adaptive inputs) is tight are given. The results broaden the class of TWCs whose capacity region can be exactly determined and imply that interactive adaptive coding does not enlarge the capacity region and is hence unnecessary for such channels. Moreover, we generalize Shannon's push-to-talk TWC and analytically derive this generalized channel's capacity region, which is a convex hull of at most four rate pairs. For general two-terminal DM-TWCs that lack channel symmetry properties, a simple outer bound is further derived to obtain approximation capacity results.

In addition to examining capacity problems, we also study joint source-channel coding (JSCC) for TWCs. Specifically, we propose an adaptive lossy JSCC scheme for sending correlated sources over two-terminal DM-TWCs. Our idea is to couple the independent operations of the terminals via an adaptive coding mechanism which can mitigate cross-interference resulting from simultaneous channel transmissions and concurrently exploit the sources' correlation to reduce the end-to-end reconstruction distortions. Our adaptive JSCC scheme not only subsumes existing lossy coding methods for the same setup, but it also improves on their performance. Several examples are given for illustration. Moreover, we derive outer bounds for our two-way lossy transmission problem and establish complete JSCC theorems in some special settings. In these special cases, a non-adaptive separate source-channel coding scheme achieves the optimal performance, thus significantly simplifying the design of the source-channel communication system.

abstract: PhD


title: “Author and Audience: Creating ‘Sanctifiction’ in Middle Byzantine Hagiography”

contributor:
Greenfield, Richard
History

subject: Byzantium, Hagiography, Authorial Role, Literature, Medieval

abstract: This project examines the authorial role in writing a successful hagiography during the so-called Middle Byzantine Period between the ninth and eleventh century. In this skeptical pre-modern society, authorial agency inevitably played a significant role in determining the success and failure of hagiographical narratives and the associated cults of the saints. I investigate the range of authorial techniques to create authority, establish holiness, engage an audience’s interest, and express potentially contentious individual ideas found in Byzantine hagiographical narratives. The observations and analysis I make in this project will demonstrate two issues: that there is a recurring set of techniques which the authors learned, modified, and applied to write a compelling story; and that these authors, despite the fact that they were writing the most religious genre of literature in their society, used their work as an opportunity to achieve personal goals. This project will make a contribution to the existing scholarship by identifying: a) the vivid presence of less religious and more personal concerns embedded within the genre of literature which is often understood to be solely focused on praising the spiritual excellence of the protagonist; and b) the range of techniques that the authors in Byzantium apparently employed to successfully appeal to their audience.

abstract: PhD


title: The theory of and practical consideration for ultrasound guided interventions: from phantom data to clinical studies

contributor:
Mousavi, Parvin
Computing

subject:
cancer
machine learning
deep learning
tissue characterization
TeUS

abstract:
Cancer is one of the leading causes of death in Canada. Research in early detection is essential for improving survival rates. The current standards for diagnosis include physical examinations, chemical tests, and biopsy. However, these tests are inaccurate and invasive. There is a need for a more accurate and less invasive diagnostic tool. To address this, Temporal Enhanced Ultrasound (TeUS) was developed.

TeUS is a method of non-invasive imaging based on the temporal response of the tissue to ultrasound irradiation. Previous studies have shown its effectiveness for in vivo and ex vivo classification of prostate cancer. Additional studies investigated the physical phenomenon of TeUS and demonstrated that the tissue response to physiological micro-vibrations recorded as a time series were the basis for tissue classification. This hypothesis was later validated through a series of simulations and tissue-mimicking phantom experiments.

Despite the clinical success of TeUS, one underlying issue is having a controlled imaging environment with standard and repeatable micro-vibrations. Additionally, specialized ultrasound equipment is required for acquisition. This thesis aims at addressing these challenges.

First, I introduced a new method of TeUS acquisition by incorporating changes to the imaging focal point in a time-dependent manner. I built 9 tissue-mimicking phantoms that differed in scatterer size and elasticity, collected TeUS, and used machine learning models to classify the phantoms. These results demonstrated the effectiveness of modifying the imaging focal point during acquisition for classification of phantoms. Second, I introduced two new methods of post-processing to further enhance ultrasound time series analysis. The first method is used to accommodate the changes to the imaging focal point, while the second method is a post-acquisition technique to create time series from a single ultrasound frame. These methods were evaluated using phantom experiments. Lastly, I demonstrated the feasibility of creating a time series from a single ultrasound frame using data collected from prostate cancer biopsy. A deep learning model was trained and results were compared to classification using traditional TeUS. The results obtained in this thesis may be useful for further improving the clinical translation of Temporal Enhanced Ultrasound for cancer diagnosis.

abstract: M.Sc.


title: Sorption of the common freshwater cyanotoxin microcystin to microplastics

contributor:
Orihel, Diane
Ortiz Almirall, Xavier
Environmental Studies

subject:
Harmful Algal Bloom
Cyanotoxin
Microcystin
Microplastic
Sorption
Biofilm

abstract: Interactions among multiple stressors in freshwater ecosystems remain poorly understood. In particular, microplastic and nutrient pollution are rarely studied in combination. However, microplastics are now commonly found in freshwater lakes with pervasive cyanobacterial harmful algal blooms, a common symptom of eutrophication. Cyanobacteria can produce various toxic secondary metabolites potentially lethal to humans, domestic and wild animals, and other aquatic life. Given the tendency of microplastics to accumulate waterborne contaminants, we assessed the sorption of the common freshwater cyanotoxin microcystin to four types of highly produced polymers: polyethylene terephthalate (PET), low-density polyethylene (LDPE), polystyrene (PS), and polyvinyl chloride (PVC). We performed laboratory batch sorption experiments with unaged and aged microplastics and an in-situ sorption experiment in a eutrophic lake. We found that waterborne microcystins sorbed poorly to microplastics under laboratory conditions irrespective of ageing; however, microplastics accumulated microcystins under natural conditions in a eutrophic lake. Further, we found that sorption capacity of microcystins differed among polymer types (LDPE ≈ PET > PS ≈ PVC), and affinity for plastic varied among microcystin congeners (MC-RR > MC-YR > MC-LR > MC-LA). Our findings led us to conclude that microplastics can directly interact with waterborne microcystins via sorption and also to hypothesize that microplastics may indirectly interact with cell-bound microcystins via cyanobacteria colonizing the microplastic’s surface. This work highlights a previously unexplored interaction between microplastics and a contaminant class prevalent in fresh water. Further, it contributes to a better understanding of the interaction between microplastic pollution and cyanobacterial harmful algal blooms, specifically the potential role of microplastics in influencing the environmental fate of toxins produced by cyanobacteria.

abstract: M.E.S.


title: Using a Mixed Methods Approach to Study the Relationship Between Mathematics Anxiety, Mathematics Teacher Efficacy, and Mathematics Teaching Anxiety in Preservice Elementary School Teachers in Ontario

contributor:
Pyper, Jamie
Education

subject:
Mathematics anxiety
Mathematics teaching anxiety
Mathematics teacher efficacy
Preservice teacher education
Teacher education

abstract: Preservice elementary school teachers are under ever increasing pressure to deliver quality mathematics instruction to their students. Mathematics anxiety and mathematics teacher efficacy are constructs that are commonly measured in preservice elementary school teachers and are used to help identify future challenges these preservice teachers might have when teaching mathematics. Mathematics teaching anxiety is a relatively new construct measured in preservice elementary school teachers. Mathematics teaching anxiety aims to separate the anxiety experienced when doing mathematics from the anxiety experienced when teaching mathematics. This study used a modified version of an explanatory sequential mixed methods design to examine the relationship between mathematics anxiety, mathematics teaching anxiety, and mathematics teacher efficacy in preservice elementary school teachers in Ontario. Participants were preservice elementary school students across six teacher education programs in Ontario. Questionnaire data was gathered from 185 participants, 16 of whom were also interviewed. Results indicate that mathematics teaching anxiety is significantly correlated to both mathematics teacher efficacy and mathematics anxiety, but there was a lack of correlation between mathematics anxiety and mathematics teacher efficacy. These results indicate that mathematics teaching anxiety does interact with mathematics anxiety and mathematics teacher efficacy and the introduction of mathematics teaching anxiety may disrupt the previous belief that mathematics anxiety and mathematics teacher efficacy are negatively correlated. Furthermore, interview and short answer responses showed that preservice elementary school teachers who were mathematically anxious were aware of their anxieties and developed methods of overcoming their feelings while maintaining effective teaching practices. These results support using mathematics teaching anxiety as a measure for identifying preservice elementary school teachers in need of help teaching mathematics ultimately leading to improved mathematics instruction in elementary school classrooms.

abstract: PhD


title: ECOLOGICAL INSIGHTS FROM δ18O AND δ13C OF AMERICAN EEL ANGUILLA ROSTRATA OTOLITHS — A COMBINATION OF LABORATORY AND FIELD APPROACHES

contributor:
Wang, Yuxiang
Longstaffe, Fred
Biology

subject:
Stable isotopes
Geothermometer
St. Lawrence River
Metabolic rate
Oxygen consumption rate
Diet
Optimum growth temperature
Critical swimming speed
Stable Isotope Ecology

abstract:
Fish species with complex life cycles, extensive migrations, or broad distributional ranges, such as the American eel, Anguilla rostrata, commonly have poorly understood ecologies because of a lack of information about their ambient environment. Stable isotopes of otoliths offer lifelong records of ambient conditions and life history, making them a promising tissue for ecological studies. However, unexplained variation in δ18O geothermometers among fish species has necessitated use of species-specific geothermometers, thus limiting the tool’s broad utility. Furthermore, interpretations of δ13C of otoliths are complicated by multiple driving factors (e.g., diet, DIC) and disputes over the possible influence of metabolic rate on both isotopes.

In this thesis, I used three controlled laboratory experiments to isolate and examine: (1) the relationship between temperature and δ18O of otoliths, (2) the relative contribution of diet versus DIC to δ13C of otoliths, and (3) metabolic rate influences δ13C and δ18O. In experiment 1, I developed an eel-specific δ18O fractionation equation (geothermometer); the slope was shallower than equations for other species. In experiment 2, otoliths reflected the full δ13C range of four isotopically distinct diets, regardless of diet quality. Mixing models showed diet contributed ~50% of total δ13C to otoliths. In experiment 3, I used the novel approach of manipulating swimming activity to induce a gradient of metabolic rates. The results showed no relationship between metabolic rate and δ13C. I propose that temperature may explain the apparent connection between metabolic rate and δ13C.

Finally, I applied the laboratory findings to an ecological study of stocked American eels in the St. Lawrence River. The δ18O of eel otoliths could be used to estimate water temperature within 0.4oC of their habitat. I used δ13C to determine habitat use after stocking and found that eels change habitat once they reach a specific age and size. Collectively, my thesis integrates three long-term laboratory experiments and 6 years of field data to elucidate the role of temperature, diet, and metabolic rate on the oxygen and carbon isotope compositions of otoliths with implications for future ecology studies of species with complex life histories.

abstract: PhD


title: Wearable Sensor-Based Sign Language Recognition Using Bio-Acoustic Signals from High-Frequency Accelerometers

contributor:
Li, Qingguo
Mechanical and Materials Engineering

subject:
sign language recognition
wearable sensors
machine learning
assistive technologies
mechanical micro-vibrations

abstract: Disabling hearing loss has a profound impact on an individual’s ability to interact and engage with those around them. Sign languages enable members of the Deaf community to communicate easily and effectively with one another. However, barriers exist for members of these populations when attempting to communicate with those who are not proficient in their language. The primary objective of this research was to develop a robust and user-oriented sign language recognition (SLR) system. This goal was accomplished through a comprehensive literature review of the wearable sensor-based SLR field, a national questionnaire to gather insights from members of the Deaf community, and the development of a novel bio-acoustic sensor system to recognize sign language gestures. Our comprehensive review of existing methods revealed many disadvantages of previous SLR systems making them unsuitable for practical applications. This literature review also revealed a disconnect between researchers and Deaf individuals, who are routinely noted as the potential end-users for SLR devices. Using this knowledge, a questionnaire was developed to gather insights and perspectives related to the SLR field directly from members of the Deaf community, family members and friends of Deaf individuals, and those who provide services targeted towards the Deaf community. Attributes including design specifications, potential applications, differences between American Sign Language and English, and other key considerations were revealed. Synthesizing our knowledge of the SLR field with the insights gathered from the questionnaire, we developed an unobtrusive wrist-worn SLR prototype. The wearable system is comprised of four high-frequency accelerometers capable of capturing mechanical micro-vibrations when placed over the major tendons of the wrist. Machine learning models were compared to demonstrate the feasibility of this system for the recognition of 15 American Sign Language gestures performed by multiple subjects. A series of validation experiments were carried out to demonstrate the effectiveness of the system. We also experimented with features to determine optimal sensor placement and the value of the high-frequency signals. Future iterations of this research will involve testing the system on larger lexicons of signs and adapting deep learning models to recognize continuous sign language sentences.

abstract: M.A.Sc.