title: The Healthy Immigrant Effect on Older Chinese immigrants in the Greater Toronto Area

contributor:
Rosenberg, Mark
Geography and Planning

subject:
Healthy Immigrant Effect
older Chinese immigrants
Ageing in Place

abstract:
In Canada, immigrants amount to approximately one-fifth of the total national population. They play significant roles in Canada’s economic and social development. From previous research, it has been observed that recent working-age immigrants are healthier than their Canadian-born counterparts, but this effect has not yet been verified among older immigrants. Canada is also facing noticeable challenges in health care service provision due to its ageing population. Among all the older visible minorities in Canada, older Chinese immigrants account for the largest visible minority group. This population encounters substantial integration challenges due to dissimilar cultural backgrounds. Integration-related difficulties such as language barriers or the access to healthcare services may also affect their health. Therefore, this thesis focuses on the health status and variations in health among the older Chinese population.
This study uses a sequential mixed-method approach to examine the Healthy Immigrant Effect (HIE) on older Chinese immigrants in Canada. On a macro-level, the health status of older Chinese immigrants in Canada is compared to the health status of both older Canadian-born residents in Canada and older Chinese in China. The data suggests that recent older Chinese immigrants have better self-rated mental health than older Canadian-born residents in Canada. On a micro-level, the self-rated health of older Chinese immigrants in the Greater Toronto Area is significantly influenced by their occupations, physical health and mental health status. A qualitative analysis of interviews with older Chinese immigrants reveals how their health is influenced by the different aspects of their post-immigration life, such as their utilization of Canada’s health care system, the environment, and their financial situation.
The findings show only weak evidence to support the HIE among older Chinese immigrants in Canada. Despite the differences among older Chinese immigrants’ clinical health and self-rated health status, it is important to understand the reasons for variations in their health from their own perspectives.

abstract: PhD


title: UNDERSTANDING THE IMPACT OF EXPERIMENTAL DESIGN CHOICES ON MACHINE LEARNING CLASSIFIERS IN SOFTWARE ANALYTICS

contributor:
Hassan, Ahmed E.
Computing

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-ShareAlike 3.0 United States

subject:
Machine learning
Software engineering
Data mining
Software analytics
mining software repositories
Defect prediction
Explainable machine learning

abstract:
Software analytics is the process of systematically analyzing software engineering related data to generate actionable insights that help software practitioners make data-driven decisions. Machine learning classifiers lie at the heart of these software analytics pipelines and help automate the process of generating insights from large volumes of low-level software engineering data (e.g., static code metrics of software projects). However, the generated results from these classifiers are extremely sensitive to the various experimental design choices (e.g., choice of feature removal techniques) that one makes when constructing a software analytics pipeline. Despite that prior studies only explore the impact of a few experimental design choices on the results of classifiers and, the impact of many other experimental design choices on generated results remains unexplored. It is critical to further understand how the various experimental design choices impact the generated insights of a classifier. Such an understanding enables us to ensure the accuracy and validity of the generated insights from a classifier.

Therefore, in this PhD thesis, we further our understanding of how several previously unexplored experimental design choices impact the results that are generated by a classifier. Through several case studies on various software analytics datasets and contexts, 1) we find that the common practice of discretizing the dependent feature could be avoided in some cases (where the defective ratio of the dataset is <15%) by using regression-based classifiers. 2) In cases where the discretization of the dependent feature cannot be avoided, we propose a framework that the researchers and practitioners can use to mitigate its impact on the generated insights of a classifier. 3) We find that interchangeable use of feature importance methods should be avoided as different feature importance methods produce vastly different interpretations even on the same classifier. Based on these findings we provide several guidelines for future software analytics studies.

abstract: PhD


title: Fluctuation moments induced by asymptotically liberating random matrix ensembles

contributor:
Mingo, James
Mathematics and Statistics

rights: Attribution-NonCommercial 3.0 United States

subject:
Free probability
Random matrices
Fluctuation moments
Discrete Fourier Transform matrix

abstract:
The topics covered in this thesis belong to the theories of free probability and random matrices. Random matrix ensembles composed of independent Haar-unitary random matrices, or independent Haar-orthogonal random matrices, are known to be asymptotically liberating, they give rise to asymptotic free independence when used for conjugation of constant matrices. G. Anderson and B. Farrel showed that certain family of discrete random unitary matrices can actually be used to same end.

We investigate fluctuation moments and higher order moments induced on constant matrices by conjugation with asymptotically liberating random matrix ensembles. We show for the first time that the fluctuation moments associated to second order free independence can be obtained from conjugation with an ensemble consisting of signed permutation matrices and the Discrete Fourier Transform matrix. We also determine fluctuation moments induced by various related ensembles where we do not get known expressions but others related to traffic free independence.

abstract: PhD


title: Placental morphology and the prediction of underlying cardiovascular risk factors

contributor:
Smith, Graeme
Biomedical and Molecular Sciences

subject:
Pre-eclampsia
Maternal Health
Pregnancy
Cardiovascular Disease

abstract: Pre-eclampsia (PE) is associated with an increased risk of future cardiovascular disease (CVD). It is characterized by new-onset hypertension and proteinuria, sometimes progressing into a multiorgan clinical manifestation. Maladaptive placentation or malperfusion, as well as predisposing cardiovascular or metabolic risk for endothelial dysfunction, contribute to the systemic inflammatory response that establishes the origins of the disease. The purpose of this study was to investigate the relationship between placental morphology and cardiovascular risk (CVR) when assessed at six months postpartum in women who experienced PE. Multivariable logistic regression was used to examine the relationship between placental morphology measures and calculated maternal lifetime risk of CVD at six months postpartum, with P<0.05 used to define significance. 186/216 women with PE who attended the Maternal Health Clinic met inclusion criteria. No significant differences were observed for placental morphometric measurements between women who screened as having a high vs. low lifetime risk profile for CVD at six months postpartum. However, using multivariable modelling that controlled for maternal age, pre-pregnancy BMI, gestational age at delivery, and severity of PE, a low placenta to birth weight ratio (<15%) was associated with an increased odds of high lifetime CVD risk (p<0.009). The findings of the current study identify clinical measurements that can be collected at the time of delivery which may help identify specific women who may benefit most from postpartum CVR screening and intervention. It was found that low placental to birthweight ratios, indicative of higher placental efficiency, were associated with an increased odds of high lifetime CVD risk in the mother when screened postpartum. Why underlying maternal CVR factors may lead to increases in placental efficiency are currently unclear, but certainly warrant further investigation and will be important to do a prospective validation study.

abstract: M.Sc.


title: Solar KK axion search with NEWS-G

contributor: Physics, Engineering Physics and Astronomy

rights: Attribution-NonCommercial-NoDerivs 3.0 United States

subject:
Axion
KK axion
Spherical Proportional Counter
Solar Corona
rare event searches

abstract: In theories with extra dimensions, the standard QCD axion has excited states with higher mass. These Kaluza-Klein (KK) axions would have a signi cantly shorter decay time and, when produced by the Sun, would remain gravitationally trapped in our Solar System, boosting their local decay rate. A low density detector would be able to distinguish such decays from background, by identifying the separate location of the capture of the two resulting photons. The NEWS-G collaboration uses low-pressure Spherical Proportional Counters, gas- lled metallic spheres with a high voltage electrode in their centre. This work aims to set exclusion limits on the solar KK axion model based on data from NEWS-G detectors.

abstract: PhD


title: Toward Smart Classrooms: Automated Detection of Speech Analytics and Disfluency with Deep Learning

contributor:
Etemad, Ali
Electrical and Computer Engineering

subject:
Speech
Stutter
Disfluency
Deep Learning
Squeeze-and-Excitation
BLSTM
Attention

abstract: Strong presentation skills are valuable and sought-after in workplace and classroom environments alike. Though they are necessary for day-to-day life, there is a lack of effective resources to help improve upon these abilities. This thesis presents a speech assessment tool capable of providing feedback on different metrics of speech quality during a presentation. The information provided by this application has the ability to identify obstacles in one's vocal performance and allows users to further develop these skills. Of the possible improvements to vocal presentations, disfluencies and stutters in particular remain one of the most common and prominent factors of someone's demonstration. Millions of people are affected by stuttering and other speech disfluencies, with the majority of the world having experienced mild stutters while communicating under stressful conditions. While there has been much research in the field of automatic speech recognition and language models, there lacks the sufficient body of work when it comes to disfluency detection and recognition. To this end, we propose an end-to-end deep neural network, FluentNet, capable of detecting a number of different disfluency types. FluentNet consists of a Squeeze-and-Excitation residual convolutional neural network which facilitates the learning of strong spectral frame-level representations, followed by a set of bidirectional long short-term memory layers that aid in learning effective temporal relationships. Lastly, FluentNet uses an attention mechanism to focus on the important parts of speech to obtain a better performance. We perform a number of different experiments, comparisons, and ablation studies to evaluate our model. Our model achieves state-of-the-art results by outperforming other solutions in the field on the publicly available UCLASS dataset. Additionally, we present LibriStutter: a disfluency dataset based on the public LibriSpeech dataset with synthesized stutters. We also evaluate FluentNet on this dataset, showing the strong performance of our model versus a number of benchmark techniques.

abstract: M.A.Sc.


title: Direct numerical simulations of aeolian noise generated by a circular cylinder in subsonic and transonic conditions

contributor:
Wu, Xiaohua
Rival, David
Mechanical and Materials Engineering

subject:
aeroacoustics
sound source
pseudo-sound
vortex shedding
wakes
acoustic pressure fluctuation
hydrodynamic pressure fluctuation
circular cylinder

abstract:
The aeolian noise generated by a circular cylinder is an important benchmark aero-acoustic problem. The overall goal of this thesis is to identify sound sources, isolate the radiating components from the non-radiating counterparts, assess their propagating capacities and to quantify the radiating acoustic sound sources versus the non-radiating hydrodynamic pseudo-sounds on and around a circular cylinder in subsonic and transonic conditions. Here, we adopt direct noise computations and the wavelet decomposition technique of Mancinelli et al. (JFM, Vol. 813, 2017), previously used in jet-noise experiments, to investigate the sound sources and pseudo-sounds generated by a cylinder. Rigorous independence and convergence analyses of the decomposition procedure are performed.

In subsonic conditions, it is found that the radiating acoustic component strongly dominates over the non-radiating hydrodynamic component at near-field locations above and upstream of the cylinder. In the oscillating near-wake region, the hydrodynamic component dominates over the acoustic component at most frequencies, except at the vortex-shedding frequency where they exhibit comparable strengths. Furthermore, within the oscillating near-wake region, the overall sound pressure level associated with the hydrodynamic pressure fluctuation exceeds that associated with the acoustic pressure fluctuation. Away from the oscillating near-wake region, the hydrodynamic pressure fluctuations decrease dramatically while the acoustic counterparts decay slowly, demonstrating that the hydrodynamic pressure fluctuation does not propagate, and that the acoustic pressure fluctuation is the only component to propagate to the far field.  Besides, it is found that the organized large-scale vortices shed from the cylinder remember their initial characteristics better as the compressibility increases.

In the transonic condition, a dominant tone at the fluctuating frequency of the separated shear layers is observed in the downstream far field. In the region of fluctuating separated shear layers, it is found that the pressure fluctuation mainly consists of acoustic component at the fluctuating frequency of the separated shear layers. Thus, the dominant acoustic waves are generated primarily by the fluctuation of the separated shear layers. It is also found that, among the various-scale vortex structures, the structure induced by the fluctuation of the separated shear layers is most closely related with both sound and pseudo-sound signatures.

abstract: PhD


title: STUDYING THE USE OF EXTRINSIC INCENTIVES TO SUPPORT CROWDSOURCED SOFTWARE ENGINEERING ACTIVITIES

subject:
Crowdsourced Software Engineering
Extrinsic Incentive
Stack Overflow
GitHub
Donation
Monetary incentive
Non-monetary Incentive
Open Source Software
Open Source Development

abstract:
Extrinsic incentives help attract participants to Crowdsourced Software Engineering (SE) activities (e.g., open source development and Stack Overﬂow contributions). There are two types of extrinsic incentives: 1) monetary incentives such as ﬁnancial rewards (e.g., vulnerability bounties) or ﬁnancial supports (e.g., monetary donations). 2) Non-monetary incentives such as badges which are a form of recognition. Prior work noted the importance of extrinsic incentives to support different forms of Crowdsourced SE activities.

In this Ph.D. thesis, we study the use of extrinsic incentives to support Crowdsourced SE activities. In particular, we focus on two of the most successful and popular examples of Crowdsourced SE activities: open source development and Stack Overﬂow contributions (e.g., answering questions). We examine the use of monetary extrinsic incentives for addressing issues in and operating open source projects, and the use of non-monetary extrinsic incentives by online technical Q&A websites.

More speciﬁcally, for monetary extrinsic incentives, we examined issues with monetary bounties for addressing them, then we studied the association between such “issue bounties” and the addressing likelihood of their associated issues across several open source projects. We also studied the use of monetary donations for supporting the operation of open source projects on GitHub by looking at how such donations are used to cover expenses across several projects. Project maintainers can leverage our study to better address issues and manage the budgets of their open source projects.

For non-monetary extrinsic incentives, we investigated the association between reputation bounties and Stack Overﬂow questions in terms of the solving-likelihood, solving-time, and trafﬁc, respectively. We observed that while reputation bounties are not a silver bullet for getting a question solved faster, they are associated with a higher solving-likelihood of a question in most cases.

Our empirical studies highlight the importance of extrinsic incentives in supporting Crowdsourced SE activities.

abstract: PhD


title: Modelling the relationship between shift work and cardiometabolic risk through circadian disruption, sleep and stress pathways

contributor:
Tranmer, Joan
Aronson, Kristan
Public Health Sciences

subject:
Shift Work
Metabolic Syndrome
Cardiometabolic Risk
Cardiovascular disease
Sleep
Stress
Circadian disruption

abstract:
Aim and objectives: The aim of this research was  to use structural equation modelling methods to test an adaption of the model proposed by Knutsson and Boggild, and to elucidate and determine the multiple pathways linking shift work exposure to cardiometabolic risk through the intermediates circadian disruption, sleep disturbances, and stress. The specific objectives were:  1) To produce a measurement model of the following latent variables: circadian disruption, sleep disturbances, and cardiometabolic risk, with adequate fit parameters; (2) To investigate the hypothesized structural model of mechanisms linking work status and shift work duration with cardiometabolic risk: (a) To determine the fit of the hypothesized model to observed data; and (b) To identify estimates of partial correlation between variables.
Methods: A cross-sectional study was conducted at the Kingston Health Sciences Centre (2011-2014) with 168 rotating shift workers and 160 day-only female workers completing self-report questionnaires, a clinical exam, 8 day accelerometer collection, and each urinary void over a 48-hour period. Validated measures were determined for psychological job stress, life stress, cardiometabolic risk, sleep and melatonin and cortisol production. A conceptual model based on a hypothesized model of physiological, behavioral and social pathways of potential mechanisms linking shift work to cardiometabolic risk through these intermediates was then adapted and tested using structural equation modelling.
Results: Status as a rotating shift worker was indirectly associated with cardiometabolic risk through circadian disruption. Specifically, status as a rotating shift work was associated in the day model with a 0.30 standard deviation (SD) increase in circadian disruption, and in the night model a 0.85 SD increase. Increased circadian disruption was also associated with an increase in cardiometabolic risk (0.47 SD for day model, 0.27 SD for night model). Shift work status was also associated with a 0.24 SD increase in sleep disturbances and a 0.26 SD increase in job stress, but these intermediates were not associated with cardiometabolic risk. Shift work duration was not associated with any intermediate.
Conclusion: Status as a rotating shift worker is indirectly associated with cardiometabolic risk, and this relationship is primarily mediated by circadian disruption.

abstract: M.Sc.


title: Paisley, Scotland’s Nineteenth-Century Shawl Designers: Innovators or Imitators?

contributor:
Helland, Janice
Art History

subject:
Art
Britain
Clothing
Design
Design Education
Design Reform
Global History
Government Schools of Design
Imperialism
India
Industrialisation
Industry
Kashmir
Manufacturing
Nineteenth Century
Paisley
Schools of Design
Scotland
Shawl
Textiles
Victorian Era

abstract:
Facilitated by increased trade between Asia and Europe, handloom-woven shawls from the Kashmir region of the Indian subcontinent became desirable clothing for Europeans connected with trade in India during the mid-eighteenth century. By the 1780s, European manufacturers had picked up on this trend, producing textiles which imitated Asian patterns but sold at lower prices to meet a wider market. Kashmiri shawls and their imitations were ubiquitous in Britain by the mid-nineteenth century and were particularly favoured by women as an outer layer of clothing.

This PhD thesis investigates the imitation Kashmiri shawl industry of one of the most renowned and prominent European producers – the town of Paisley, Scotland – to assess the artistic innovation of local shawl designers between 1805 to 1870. Having initiated production in 1805 – years later than its British competitors in Edinburgh and Norwich – by the mid-nineteenth century Paisley’s name was synonymous in much of the Anglophone world with the teardrop-shaped floral motif that was iconic of the Kashmiri shawl. However, during the 1830s manufacturers in Norwich and Edinburgh vocally complained of Paisley designers ‘pirating’ their work. These accusations encouraged more rigorous intellectual property laws, as well as the nationwide establishment of government-subsidised schools of design during the 1830s and 1840s. It was hoped that the Paisley Government School of Design (founded in 1848) would train local designers to create original, quality patterns.

Tracing the oft-intertwining effects of globalisation, industrialisation, and national design reform upon the role of designers in nineteenth-century British textile industries, I examine Paisley manufacturers’ leading role in producing imitation Kashmiri shawls by asking several fundamental questions: What kind of design culture existed in Paisley? Did Paisley’s shawl designers bring any innovation to the visuality and materiality of the imitation Kashmiri shawl? How much did European shawl designers (including those in Paisley) rely on the patterns of their competitors, including South Asian patterns, to produce their own work? And did the Government Schools of Design improve the quality and originality of patterns in the shawl industry? Resolving each of these questions will clarify whether design innovation was a factor in Paisley’s economic success.

abstract: PhD


title: The role of avoidance and stress in understanding emotional dysfunction in adults and adolescents with a fixed emotion mindset

contributor:
Hollenstein, Tom
Psychology

subject:
Emotion
Mindset
Implicit Theory
Anixety
Depression
Adolescence
young adults
avoidance
social avoidance
perceived stress

abstract: Emotion mindsets refer to global beliefs about the controllability of one’s emotions. Individuals with fixed emotion mindsets view their emotions as uncontrollable and believe that no effort or strategy on their part can alter them, and these individuals display high rates of internalizing symptoms. Thus, holding a fixed mindset represents a vulnerability for emotional dysfunction; however, the proximal factors and circumstances that explain this relationship for fixed individuals are unclear. For my dissertation, I examined whether the use of avoidance-based regulation strategies were the process by which mindsets might indirectly influence internalizing symptoms in two age groups: first year post-secondary students (17 to 21 years old;  Study 1 & 2) and adolescents (13 to 15 years old; Study 3). Avoidance is a strong predictor of internalizing symptoms and fixed individuals are shown to use avoidance in response to negative emotions. Furthermore, I examined this relationship within the context of perceived levels of stress. High levels of perceived stress increase negative emotions which may trigger emotion mindsets more strongly since mindsets become more salient when stress is high (Michl et al., 2013; Zautra et al., 2002). Post-secondary school and adolescence are well-known periods of transition known to increase levels of stress. In Study 1, (N=163; mean age = 17.9), a fixed emotion mindset was associated more with use of avoidance-based strategies, and greater presence of depression and anxiety symptoms in undergraduates. Furthermore, avoidance-based strategies accounted for a significant indirect effect between mindset and anxiety, but not depression. Study 2 (N=183; mean age = 18.7) was a conceptual replication of the Study 1 model and extended this finding by examining the moderating role of perceived stress. Avoidance-based strategies indirectly explained the relationship between both anxiety and depression; however, there was no moderating effect of perceived stress.  In Study 3 (N=187; mean age = 13.9), avoidance-based strategies indirectly explained the relationship between anxiety and between  depression; however, levels of perceived stress did not significantly moderate the indirect relationship. Overall, these studies extend the literature on emotion mindsets by expanding the knowledge on the behaviour of fixed individuals who are relatively understudied and are most vulnerable to emotional dysfunction. Discussions will focus on the general themes of the dissertation, such as expanding on what it looks like to be an individual with a fixed emotion mindset and how these mindsets might develop. Clinical implications of these results, as well as considerations for future studies, are also discussed.

abstract: PhD


title: FILTERS FOR SEPARATION OF PARTICLES OF DIFFERENT SIZES AND OIL FROM EMULSIONS

contributor:
Liu, Guojun
Chemistry

subject:
filter
size
emulsion separation
electrospinning

abstract:
With increasing concerns over water contamination, the purification of water is critical.  For water purification, filtration is widely used for its convenience, low cost, and efficiency.  In this thesis, two types of filters are developed for the separation of particles of different sizes and for the separation of oil from emulsions.
      First reported is the fabrication of an inverse size-selective membrane templated by an electrospun nanofiber mat.  The electrospinning of a polymethyl methacrylate (PMMA) solution yielded long nanofibers that folded into mats.  The nanofiber mats were then annealed at selected high temperatures under pressure to fuse fiber section at junctions.  Infusing partially hydrolyzed polyvinyl acetate (HPVAc) into the voids between these fiber sections, crosslinking the infusing polymer, and subsequently removing the nanofiber template produced an inverse porous membrane.  Liquid flux across such membranes increased by increasing the annealing temperature of the fiber mats and by etching the surfaces of the final membrane with plasma to expose the encapsulated nanochannels.  The membrane could also separate particles with different sizes and the cut-off size of the separation increased as the mat annealing temperature increased.  Thus, the extent of nanofiber fusion at their junctions determined the size selectivity of the membrane.
      Secondly, sintered glass funnels were hydrophobicized by running a treatment solution through and the hydrophobicized funnels could separate oil from water-in-oil emulsions. Chloro(dimethyl)octadecylsilane (CDMOS) was the modifying agent used for the funnels.  Glass funnels with three pore sizes were modified with the same concentration of CDMOS to investigate the effect of varied pore size on the wetting properties and separation performance of the glass filters.  Water sliding angles increased as filter pore size increased.  However, transparent oil could be separated from water-in-oil emulsion only for h the fine- and medium- pore funnels.  The separation occurred most likely due to the blocking of the water droplets by hydrophobic pores.

abstract: PhD


title: Release of a proposed activator of spreading depolarization by abrupt hyperthermia

contributor:
Andrew, David
Neuroscience Studies

subject:
spreading depolarization
hyperthermia
stroke
migraine
palytoxin
ouabain

abstract: Spreading depolarization (SD) is a wave of lost membrane potential moving across the gray matter within 1-2 minutes of metabolic compromise as during stroke, post-injury fever or migraine aura. Research is ongoing to protect the brain from the potentially damaging effects of SD on neurons, but progress has been slow because the molecular events initiating and sustaining SD are poorly understood. Therefore, we searched for evidence of an SD activating molecule (SDa) which is released from metabolically stressed gray matter and triggers SD, essentially acting like an endogenous palytoxin (PLTX). First, we tested if SD could be routinely evoked in a naïve, healthy brain slice by elevating the temperature quickly from 35 to 40oC. This “hyperthermic SD” (htSD) was confirmed using light transmittance (LT) imaging. Then, SD induction was attempted in a naïve slice by superfusing the artificial cerebral spinal fluid (aCSF) which previously bathed several slices undergoing htSD. This solution was termed “aCSFPost-SD” and was suspected of containing a released SDa. In support, SD could be evoked by aCSFPost-SD in ~62% of naïve slices at a normal temperature of 35oC. Moreover, SD onset evoked by the aCSFPost-SD was unaffected by slight elevations in [K+]O (5 mM) or by the inhibition of glutamate receptors by kynurenic acid (2 mM). SD induced by O2/glucose deprivation (OGD) was also not hindered by rostafuroxin, which blocks the inhibitory effect of a potential endogenous ouabain (EO). Chemical analysis of the aCSFPost-SD using size-exclusion high pressure liquid chromatography (HPLC) and matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI-IMS) detected compounds with MW of ~300-400 and ~500-600 Da associated with SD. Analysis of HPLC traces of substances released from brain slices evoked by brief hyperthermia, by OGD or by high [K+] revealed the same elevated peaks, implicating biomolecules common to SD in general.  Further characterization of SD-related molecules will help us identify an SDa as part of a continuing effort to identify therapeutic targets/biomarkers involved in SD-associated acute brain injury.

abstract: M.Sc.


title: THE CHALLENGES AND OPPORTUNITIES FOR  SCHOOL GARDEN PROGRAMS IN ONTARIO

contributor:
Power, Elaine
Kinesiology and Health Studies

subject:
school gardens
environmental education
experiential education
food literacy
sustainable agriculture

abstract:
School garden programs offer students opportunities to experience and participate in the processes of nature and agriculture through hands-on learning in a wide variety of outdoor settings. Although the value of school gardens has been well documented, my 7-year experience as a school garden facilitator is that there is little or no concrete support for these programs within the public-school system itself, either at the local or the provincial level. Most programs operate through the vision and dedication of community members and organizations and/or the efforts of individual educators.
The purpose of this study is to investigate how school garden programs are implemented in a variety of educational settings and to identify the challenges and opportunities that exist within them. For my research I conducted ten semi-structured interviews with teachers, educational assistants and community members who acted as school garden program facilitators. Data from these interviews was coded and analyzed to identify key themes as well as situation specific anecdotes.
Findings from my study indicate that there are as many models for school garden programs as there are facilitators. Each program is uniquely adapted to the skills and abilities of the facilitator as well as to the setting in which the program takes place. However specific challenges such as the lack of funding and implementation time were universal to all programs. I hope that this work will provide useful insights for other schools and other districts, both in Ontario and across Canada, as well as contribute to almost the non-existent literature on the implementation of school garden programs.

abstract: M.Sc.


title: Behavioural Manifestations and Relational Correlates of Individual Differences in Theory of Mind

contributor:
Harkness, Kate
Psychology

subject:
psychology
theory of mind

abstract: Although it is impossible to know the contents of others’ minds with absolute certainty, we can (and do) make probabilistic guesses about what others are thinking or feeling. When these judgments are made based on observable information, we refer to this skill as “theory of mind decoding.” There are individual differences in how accurately adults make theory of mind decoding judgments, and how motivated they are to use this skill in daily life. However, surprisingly little is known social correlates of these individual differences. The current dissertation examined whether theory-of-mind decoding skill, motivation to use this skill, and their interaction predicted three categories of social behaviours: conversational skills, cognitive sensitivity, and mental state language. Further, I explored whether these social behaviours predicted relational success, strangers’ ratings of participant likeability after an initial encounter. Participants were 334 undergraduate students who participated in a cooperative building task with a same-gender stranger. Social behaviours were coded based on video recordings of the building task. Theory-of-mind skill was assessed using the Reading the Mind in the Eyes task, and motivation to use theory of mind was assessed using the self-reported Mind-Reading Motivation scale. Results suggested that theory-of-mind skill, motivation to use this skill, and their interaction did not directly predict partner ratings of participant likeability. However, individual differences in theory of mind did predict partner ratings of participant likeability indirectly through cognitive sensitivity. Further, theory-of-mind skill and motivation to use this skill manifested in different aspects of conversational skills and mental state language, although these behaviours were not significant predictors of partner ratings of participant likeability. Taken together, the results of this study support the general assertion that individual differences in theory of mind are important for social interactions, even among healthy adults, and highlights the basic social cognitive processes that facilitate successful interpersonal interactions.

abstract: PhD


title: MODELLING AND EFFICIENCY OPTIMIZATION OF WIRELESS POWER TRANSFER SYSTEMS HAVING ONE OR TWO RECEIVERS

contributor:
Jain, Praveen
Electrical and Computer Engineering

subject:
Wireless Power Transfer
Modelling
Efficiency
cross-coupling

abstract:
This thesis presents a study on the modelling of wireless power transfer systems and techniques to improve system efficiency. Using time domain modelling, useful modes of operation are identified, and performance graphs are plotted which help in designing the system for various consumer specifications, like power delivery and efficiency. The modelling is useful in finding curves for voltage gain, rms current, turn-on current of switches, ZVS angle, peak stresses across capacitors and switches, etc., as a function of load, operating frequency and coupling coefficient among receivers and transmitters. The regions of operation where zero voltage switching (ZVS) is obtained are also found as a function of load, coupling coefficient and system gain. Modelling of wireless power transfer systems is done predominantly using frequency domain modelling which approximates the currents and voltages in the resonant tank to be sinusoidal waveforms. Hence it provides an approximate analysis which requires overdesign of components to account for inaccuracies in the modelling. Time domain analysis as presented in this work gives exact solutions to designers. Experimental results on a wireless power transfer system prototype with one and two 5V, 5W receivers show the accuracy of the time domain modelling.
This thesis also provides a comprehensive analysis of efficiency optimization for systems involving one or more receivers. For systems with voltage regulation on the output side, a study in this thesis demonstrates the required gain of the power conditioning unit to get a better system efficiency. This study is verified with experimental results on a system with half bridge inverter and rectifier on transmitter and receiver, respectively. For receivers with cross-coupling among them, the resonant frequency of the system changes. This work shows that the presence of cross-coupling between the receivers may or may not be beneficial to efficiency, so the focus is on the improvement of efficiency in its presence rather than the elimination of cross-coupling. To improve the efficiency, a switched capacitor network has been proposed that varies the resonant frequency of the receivers in the presence of cross-coupling to improve the total system efficiency using a perturb-and-observe algorithm. Experimental verification of a WPT system with two 5V, 5W receivers (having cross-coupling) show the validity of the analysis and proposed technique to improve efficiency.

abstract: M.A.Sc.


title: Examining the Interactions among Second Language Teachers’ Pedagogical Content Knowledge, Knowledge of Metacognition, and Their Influence on Teaching Metacognition

contributor:
Matheson, Ian
Education

subject: Knowledge of Metacognition

subject: Teaching Metacognition

subject: LINC program

subject: Adult ESL learners

abstract:
Three critical constructs in relation to teachers’ instruction were examined in this study. They are pedagogical content knowledge, knowledge of metacognition, and the teaching of metacognition. Pedagogical content knowledge is domain specific, which includes teachers’ knowledge about the subject and the translation of this knowledge into classroom activities. Knowledge of metacognition, on the other hand, is domain general, refers to the knowledge of identifying and delineating effective usages of general strategies in learning and self-knowledge. The teaching of metacognition refers to creating conditions where learning and fostering of metacognitive skills becomes plausible. This study examined the interactions between these two knowledge domains and their influence on teaching metacognition to second language adult learners in Language Instruction for Newcomers in Canada (LINC) classrooms.

Based on Shulman’s (1987) teachers’ knowledge base categories, studies by Gatbonton (2008), Tarnanen (2015), Edwards (2014) explored teachers’ pedagogical content knowledge domain. Following Paris et al.’s (1983) framework, the metacognitive knowledge of teachers was examined in Wilson and Bai’s (2010) study that showed pre-service teachers lack of instructional knowledge in this domain. However, the interaction between these two domains and whether the interaction influence teaching metacognition to adult learners has not been discovered in second language context (i.e., LINC classrooms).

To address this research gap, this study examined the three constructs using a qualitative approach. Eight LINC teacher participants answered 15 open-ended questions in 60-minute interviews. The questions were based on deductive categories related to the constructs. The inductive analysis of the data resulted in themes in all three constructs. The results suggest that the distinct knowledge areas (pedagogical knowledge, content knowledge, knowledge of curriculum and knowledge of learners) within LINC teachers’ pedagogical content knowledge are interconnected. The findings also suggest that teachers have better understanding in the declarative knowledge category of metacognition rather than in procedural and conditional categories. This understanding of metacognition is rooted more in practice rather than theory, which amalgamates with pedagogical content knowledge and influences their teaching of metacognition. The conclusion suggests future research in constructing LINC teachers’ explicit knowledge of metacognition (in all knowledge categories) through preservice and in-service teacher education programs.

abstract: M.Ed.


title: CHARACTERIZING THE ANTIVIRAL PROPERTIES OF M2A MACROPHAGES

contributor:
Basta, Sameh
Biomedical and Molecular Sciences

subject:
polarized macrophages
virus
LCMV
interleukin-4
antiviral
R848

abstract:
Macrophages (Mφ) are innate immune sentinels that can acquire highly heterogeneous phenotypes depending on their cytokine microenvironment. Mφ exhibit distinct activation patterns across a continuum from pro-inflammatory (M1), associated with the Th1 cytokine IFNγ, to anti-inflammatory (M2a), associated with the Th2 cytokine IL-4. However, emerging evidence indicates that IL-4 can play a role in promoting inflammation in certain conditions. In asthma and allergic inflammation, IL-4 mediates pro-inflammatory responses which lead to tissue damage. Consequently, other co-factors and cytokines present in the microenvironment greatly influence the effect of IL-4 on the outcome of the immune responses. As Mφ play a crucial role in regulating innate and adaptive immunity, their activation status directly influences the outcome of viral infections. However, little is known about the responses of M2a Mφ to viral infections.
To this end, we first characterized the murine Mφ cell line BMA as a model for in vitro polarization. We found that that the BMA cell line can be polarized into M1/M2 phenotypes, and can therefore be used as a model for in vitro Mφ polarization reducing the need for primary Mφ isolation when investigating biological phenomena related to their polarization. Next, we characterized the signal pathways induced by different lengths of treatment with IL-4 utilizing primary spleen-derived Mφ (SpM). We report that sustained priming with IL-4 alone promotes an antiviral response in Mφ, and enhances pro-inflammatory responses to TLR7 stimulation using R848 (resiquimod).
Finally, we investigated the response of activated SpM to lymphocytic choriomeningitis virus (LCMV) infection. Following infection, polarized Mφ show an increased resistance to LCMV infection. We show for the first time that the altered resistance of M1 and M2a Mφ occurs through distinct signaling mechanisms, possibly due to shifts in their immunometabolism.
The results presented in this thesis highlight the need for better understanding IL-4 pro-inflammatory functions and its potential use as an immunotherapeutic. It may be used as a broad-acting antiviral in combination with R848 or other therapies to target the innate arm of immunity against emerging infections. Furthermore, understanding the mechanism through which IL-4 regulates inflammation may reveal new treatments for chronic inflammatory disorders.

abstract: PhD


title: Arch-rivals? The roles of the windlass and arch-spring mechanisms in running

contributor:
Rainbow, Michael
Mechanical and Materials Engineering

subject: foot biomechanics windlass arch-spring x-ray running arch

abstract: The human foot is an integral part of locomotion due to its broad range of function. Its versatility derives from mechanisms that originated from cadaveric or static experiments, and were extrapolated to locomotion. Two such mechanisms are the windlass mechanism (Hicks, 1954), where the dorsiflexion of the metatarsal-phalangeal joints shortens and raises the arch through plantar fascia tension, and the arch-spring (Ker et al., 1987), where the arch-spanning ligaments store elastic energy in foot compression and return it in recoil. The clinical and research communities dogmatically accept that the windlass mechanism stiffens the foot for propulsion, which this work tested in vivo in a dynamic compression apparatus. Unexpectedly, the windlass mechanism made the arch more compliant, absorbing more energy when the windlass mechanism was engaged, compared to when it was not. This result suggests that the windlass mechanism’s function is to passively reduce arch apparent stiffness by changing its shape. The windlass mechanism’s ability to manipulate arch shape during running could be influenced by a straining plantar fascia however, as the plantar fascia is an important contributor to the arch-spring. Measured using high-speed biplanar x-ray imaging, there is a period just after the onset of heel-lift where the plantar fascia demonstrates pure windlass behaviour. The stretched plantar fascia is then released, and the arch rising effect of the windlass mechanism is enhanced by arch- spring recoil. The purpose of the recoiling arch has previously been suggested to propel the body’s centre-of-mass forward and upward, despite the relatively small magnitude of arch rise. Using a simulated arch without recoil, I identify that the arch-spring does not contribute directly to lifting the centre-of-mass. Instead, the recoiling arch increases the time available for the ankle to plantarflex and provides a mechanical advantage to the ankle plantar flexor muscles. Overall, this work contributes to an improved understanding of healthy foot function, which can underlie advancements in treatments for pathology and injury; footwear design to enhance performance; and, biomimetic robots and prostheses such that they more accurately represent foot function.

abstract: PhD


title: Physical and numerical modeling of landslide-generated wave runup on steep slopes

contributor:
Mulligan, Ryan
Take, Andy
Civil Engineering

subject:
solitary wave runup
landslide-generated waves
tsunamis
physical modeling
numerical modeling
SWASH

abstract: Landslides generate waves when they fall into water, and these waves can be major hazards where they interact with coastlines and runup slopes on land. In this thesis, physical and numerical models of landslide-generated waves on steep slopes were constructed and used to develop a deeper understanding of the runup process. First, a physical model was developed to investigate landslide wave runup. Impulse waves were generated in a series of laboratory flume experiments by releasing a range of different slide source volumes of highly mobile slide material (water) into different reservoir depths, to observe the runup of waves that are breaking and non-breaking on steep slopes ranging from 25° to 45°. The maximum runup and the cross-slope variability in runup of each wave was captured using hydrochromic paint, which changes colour on contact with water, and this novel technique was developed as part of this thesis. The experimental results indicate that in the near-field the runup of breaking waves is dependent on the wave amplitude relative to the water depth, and is nearly independent of the slope angle. The observations, combined with runup data from previous studies, are used to develop a new semi-empirical equation for runup of breaking and non-breaking waves. The formulation is valid over an extended range of relative wave amplitudes, relevant for near-field runup that has been documented in major field cases. The experimental observations provide, for the first time, a comprehensive dataset of near-field runup for breaking and non-breaking impulse waves. Second, a high-resolution phase resolving numerical model was applied to investigate landslide wave runup. The non-hydrostatic SWASH model was used to simulate wave propagation and runup corresponding to the laboratory experiments. The model adequately resolves the propagation and interaction of the incident wave with the slope but does not capture the very thin and fast fluid flow that reaches the maximum runup in the experiments, especially for cases when the waves are breaking. In future, the benchmark experimental dataset on impulse wave runup collected in this study can be used to validate other types of numerical models.

abstract: M.A.Sc.


title: Investigating Embryonic Gene Expression Changes in a Rat Model of Congenital Heart Defects and Longitudinal Effects on Postnatal Cardiac Structure and Function

contributor:
Ozolinš, Terence
Winn, Louise
Adams, Michael
Biomedical and Molecular Sciences

subject:
congenital heart defects
ventricular septal defects
echocardiography

abstract: Congenital heart defects (CHD) are the most common birth defect, occurring in approximately 1% of all births and continue to be a significant cause of infant morbidity and mortality. Ventricular septal defects (VSD) account for the majority of CHDs and result from incomplete formation of the interventricular septum. To produce a population of offspring with VSD in a reproducible and dose-dependent manner we administered dimethadione (DMO) to pregnant Sprague-Dawley rats during the sensitive window of embryonic heart development. DMO, a discontinued anticonvulsant drug, is a potent heart teratogen; when administered in six doses it produces 74% incidence of VSD with poor postnatal viability, whereas four doses produces 43% VSD with greater postnatal survival. We aimed to use these models to test the hypothesis that in utero exposure to DMO interferes with normal gene expression patterning in the developing heart, resulting in CHDs which spontaneously resolve postnatally, yet exhibit maladaptive responses when challenged with isoproterenol (INE), a cardiac stressor. In Chapter 2 using the six dose model, we show that DMO exposure decreased mRNA expression of Gata4 in left ventricle and increased the expression of Myl2 in the atria, prior to formation of the ventricular septum. A critical review of the uses and technical considerations required for the use of echocardiography in developmental toxicity studies is provided in Chapter 3. This method of assessment was used in Chapter 4 to characterize the structural and functional development of male rat hearts exposed to four doses of DMO in utero. In this study, differences from control that were observed early postnatally, such as stroke volume, resolved by weaning, but re-emerged in adulthood. Using this cohort of body weight matched rats, we used increasing, intermittent doses of INE to stress the heart, as described in Chapter 5, and the cardiac effects were monitored via ultrasound. We observed decreased structural parameters in the DMO exposed rats, including left ventricular mass and diameter, and differences in function, evidenced by the changes in longitudinal fractional shortening. Taken together, these findings contribute to our understanding of how in utero chemical exposures may lead to VSDs and the importance of long-term follow up in spontaneously resolved VSDs and the potential for altered adaptation to cardiac stress in later life.

abstract: PhD


title: Initial characterization of a subgroup of Arabidopsis group VIII receptor-like cytoplasmic kinases in immune and flowering time pathways

contributor:
Monaghan, Jacqueline
Biology

subject:
Plant biology
Kinase signaling
Immunity
Development

abstract:
In order to defend against disease, plants have evolved a tightly coordinated signaling network to rapidly prevent the spread of infection. Given the severity of yearly crop loss to pathogen threats, further understanding of how plants defend against pathogens is vital to the improvement of current agricultural strategies. Receptor protein kinases on the plant cell surface recognize microbes and trigger phosphorylation-dependent signaling events, ultimately leading to genetic reprogramming. Receptor-likecytoplasmic kinases are key mediators of immune signal transduction, but many remain largely understudied. This thesis focuses on the group VIII RLCKs in Arabidopsis thaliana, also known as the AtPTI1-like kinases, for which an immune function has not been shown. Using a functional genomics approach, I demonstrate that a subgroup of the group VIII RLCKs regulate flowering time and may additionally function as negative regulators of immunity by mediating the oxidative burst. Additionally, I found that one of these RLCKs, PTI1-1, interacts with the negative regulator of defense CALCIUM -
DEPENDENT PROTEIN KINASE 28 (CPK28) and the positive immune regulator BOTRYTIS INDUCED KINASE 1 (BIK1), further suggesting the involvement of these RLCKs in immune signal transduction. Broadly, this work has shown two novel functions
for the AtPTI1-like kinase family in both defense and development, and primes future research for this previously uncharacterized group.

abstract: M.Sc.


title: Isomorphisms of Galois Representations of CM Elliptic Curves

contributor:
Kani, Ernst
Mathematics and Statistics

subject:
galois
elliptic curves
mathematics
representation
number theory
representation
complex multiplication
cm
mazur's problem
galois representation
division field
weber field
ideal isogeny
isogeny

abstract: In this thesis, we consider the problem of determining all CM elliptic curves over $\rat$ whose mod $N$ Galois representations are isomorphic to the mod $N$ Galois representation of a given CM elliptic curve over $\rat$. By utilizing the results from the theory of complex multiplication as well as building on the works of Kani and Kwon on isogenies of CM elliptic curves and Zywina's work on the images of Galois representation over $\rat$, we are able to make substantial progress towards fully answering this problem.

abstract: PhD


title: Searching for a ‘Working-Class Hero’ in Greek Old Comedy

contributor:
Griffith, R. Drew
Classics

subject:
Greek Comedy
Labour Studies
Aristophanes
Working Class
Paid Labour
Theatre Audience

abstract:
The attitudes towards work and labour in antiquity vary based on lens and scholar,
ancient or modern. This project aims to make new connections between the realms of Labour
Studies and Classics through the examination of ancient literature, with a focus on the fifth
century BCE. Specifically, it examines a selection of the comic poet Aristophanes’ works in
order to determine whether or not a ‘working-class hero’ existed within them. Additionally, it
explores what impact, if any, this character type may have had on ancient theatregoers, and how
the working-class hero lines up with a staple of Old Comedy, the comic hero.
In order to investigate this, context is key. This project first provides relevant
vocabulary, both in English and Greek, with definitions specific to this body of work. Following
this are examples of paid labour in antiquity. This project finds that there is ample evidence of
paid labour across industries in the fifth century BCE, both in public and private spheres. In the
former, the surviving records provide far more exact wage information, and while the latter is not
as specific, it still indicates some sort of compensation for work.
This project finds that there is a connection between working-class heroes and Old
Comedy. The parallels between working-class and comic heroes are numerous, and appear in
more than one Aristophanic play. The poet’s protagonists were almost always average, everyday
men, pushing back against power structures in order to make change for the better. In addition,
there is reason to believe that the audience felt a connection to the comic hero as a working-class
hero. Through analysis of specific scenes, Aristophanic patterns and tropes, as well as the results
of competition, it becomes clear that spectators likely would have related to the contents of the
plays. This study demonstrates that, through examining Old Comedy from a labour-based lens,
there are clear connections between these two vastly different disciplines.

abstract: M.A.


title: The Ultranationalist International: Fascism in Global Historical Perspective

contributor:
Chowdhury, Amitava
History

subject:
Fascism
Ultranationalism
Global History
Nacionalismo
Hindutva
Nazism

abstract:
The following is an effort to conceptualize fascism as a global historical problem. Given its ultra-nationalistic bent, approaching fascist movements as a phenomenon entirely distinct to particular national contexts seems logical. However, fascist regimes and movements emerged simultaneously across the world in the interwar period. Therefore, studying fascism in global historical terms can reveal different aspects of the oft-nebulous subject of fascism that are not as readily apparent when studying fascist movements strictly in terms of the peculiarities of their specific national manifestations.
	The first chapter outlines the dimensions of the global historical approach to fascism in historiographical terms, highlighting some of the problems of boundaries and definition that have plagued the study of fascism as well as the limits of studying fascist regimes entirely within the confines of particular national movements and the unique national factors which shaped their emergence. The second chapter develops an analysis of the emergence of ultra-nationalistic politics especially in the contexts of India and Argentina, where fears of degeneracy and the dissolution of the social order were shaped by allegedly anti-national groups and movements that were seen as posing an imminent and existential threat to the national community. Finally, the third chapter locates fascism within the broader political spectrum in global terms, taking advantage of multiple cases to evaluate broad similarities across different fascist movements in terms of general political orientation. While fascism can be characterized as a retreat from the global and to the nation, viewing fascism as a global historical problem reveals the ways in which this orientation towards ultra-nationalist politics was in fact reflective of the powerful influence of global processes and transnational movements on national politics in the interwar period.

abstract: M.A.


title: DEVELOPMENT OF ROBUST AND SENSITIVE NANO-ELECTROSPRAY IONIZATION SOURCE WITH NOVEL MULTI-CHANNEL EMITTER COUPLED WITH MASS SPECTROMETRY

contributor:
Oleschuk, Richard Dr.
Chemistry

subject:
NanoESI
Ion Source
NanoESI source

abstract: Nanoelectrospray ionization (nanoESI) provides high sensitivity due to increased desolvation efficiencies developed through the production of nanometer sized droplets. Unfortunately, this sensitivity is often traded for poor robustness and reproducibility, where conventional nanospray emitters/sources are prone to both clogging and spray irreproducibility. In conventional nanoESI the use of a multi-channel emitter is of interest for generating nanoelectrospray due to its lower chance of clogging, high sample throughput and improved sensitivity. In comparison to a single-tip emitter forming a single Taylor cone, a multiple emitter forms a plume of mist. This plume is attributed to multiple Taylor cones formed from multiple channels. Sensitivity gain is related to the square root of the number of emitters. The multi-channel emitter is expected to spray a larger volume in an efficient manner and reduce the tendency to clog. However, to eliminate the dependency of sprayer plume or the Taylor cone effect, we have developed a nanoESI ion source (GenieTM). Thus, lower chances of clogging and improved sensitivity are expected to provide improvements over conventional nanoESI emitter. Genie is a novel ion source vessel that makes use of a carrier gas flow to transport ions generated in the channel of the vessel to the sampling orifice of the MS, decoupling the outlet of the sprayer from the inlet of the MS. Thus, the signal stability and reproducibility do not depend on the sprayer plume or the Taylor cone effect. Also, improvements in the desolvation process results in better ionization efficiency and reduction in background noise. Genie’s physical geometry provides the flow conditions for minimum ion neutralization. It also eliminates the need for curtain gas (reducing complexity). Overall, GenieTM is an interface that utilizes a novel laminar-flow based heated source for induced desolvation and a pneumatic flow focusing module to enhance nanoESI stability and robustness.

abstract: M.Sc.


title: Political Obligation and Collective Self-determination: An Associative Account

contributor:
Moore, Margaret
Political Studies

subject:
Associative Duties
Political Obligation
The Right of Self-determination
Political Community

abstract:
This thesis is concerned with the special duties and group rights that the citizens of a state may have. It develops an associative account that relates the idea of associative duty to both political obligation and collective self-determination. The three essays that constitute the core of this thesis each focus on associative duty, political obligation, and collective self-determination.
Essay 1 lays foundations for an associative account of both political obligation and collective self-determination. It argues that value-based theories, which grounds associative duties on the value of special relationships, cannot show the moral weight of special relationships. Then the essay develops the expectation-based account of associative duties: one has special duties to one’s intimates and associates that arise from one’s special relationships with them because they form interactive expectations of one’s actions that one can fulfill without violating general duties.
Essay 2 discusses the justification of political obligation. It inspects standard associative theories, which regard our political obligation as an associative duty that arises from our special relationship with our compatriots. It argues that these theories rely on accounts of associative duties that are either inapplicable to political communities or implausible. The main task of the second essay is to develop an instrumental associative theory holding that we have political obligations because our states serve as an instrument for promoting our associative duties to our intimates.
Essay 3 explores the conception of a people, the primary holder of the right of self-determination, and the basis of this right. It shows that standard associative theories of collective self-determination face an indeterminacy problem. Then the essay defends a conception of a people as a network community. It argues that individuals have an associative interest in participating in the same self-determination project as their intimates and associates, and that the self-determination of a network community can promote its members’ associative interest. The essay also argues that an actual community can be a network community if its intra-group connections are much stronger than its inter-group connections and it opens its membership to non-members who are specially connected to its members.

abstract: PhD


title: INTELLIGENT FRAMEWORK FOR MONITORING CROPS IN GREENHOUSES

contributor:
Hassanein, Hossam
Computing

subject:
Wireless Sensor Network
Wireless Visual Sensor Network
Machine Learning
Deep Learning
Image Processing

abstract:
Wireless Sensor Networks (WSNs) and Wireless Visual Sensor Networks (WVSNs) are two monitoring technologies that have the potential for use in many application domains, and both are poised for growth in many markets from the farm to the office.  Integrating a WSN with a WVSN in a commercial greenhouse setting is an application domain yet to be researched. The integration of WSN and WVSN has the potential to overcome the problems other monitoring systems have encountered. A system combining these two wireless networks will need no human interaction, deliver real-time data indicating an adverse event, be cost-effective, and use less power. Additional efficiencies specific to the greenhouse application are needed due to its clutter and occluded environment, very large area, and restricted energy plan. This thesis presents a framework that combines WSN, WVSN, Machine Learning (ML), deep learning, and image processing to address the challenges faced by operators of commercial greenhouses. The framework achieves three objectives. First, finding the optimal placement of WVSN nodes to minimize the number of installed camera nodes. Second, monitoring the growth of the plants and detect any abnormalities caused by pests or diseases. Third, controlling the microclimate inside the greenhouse and dynamically predicting the duty cycle activities of the monitoring sensors.
Our first objective is achieved by formulating and solving an optimization problem to find the best placement for the camera sensors of the WVSN, maximize the area covered, and minimize the number of camera sensors used with good quality images. The second objective is achieved by using the Hough Forest ML and image processing techniques on the images taken by the WVSN to detect any fungus, monitor the growth of the plant, and to increase crop production and quality. Our third objective is achieved by controlling the microclimate inside the greenhouse using deep learning prediction Long Short-Term Memory (LSTM) model. The prediction model will not only control the microclimate inside the greenhouse but also predict and control the monitoring sensor’s duty cycle to decrease energy consumption and prolong the network’s lifetime.

abstract: PhD


title: UNSETTLING SETTLERS’ COLONIAL PRIVILEGE THROUGH PERFORMANCE:  MOVEMENT, SOUND, PARTICIPATION, PLAY, LAUGHTER.  PHASE ONE

contributor:
Mackey, Clarke
Cultural Studies

subject:
Colonization, Decolonization,
Participation
Play
Privilege
Productive Discomfort
Settlers

abstract: Unsettling Settlers’ Colonial Privilege Through Performance: Movement, Sound, Participation, Play, Laughter. Phase One is a research-creation thesis on the development and testing of a life-sized board game designed to enable Canadian colonial settlers to examine their prejudices and acknowledge their biases towards the first peoples of this land (First Nations, Métis and Inuit), and explore actions they can engage in to decolonize themselves and Canada. This is the written component of the project, which I have used to examine what my team and I have undertaken on a practical level, and ask how we can develop the game in the future. I am using this thesis as an artistic tool - a personal and practical analysis of what I have learned during my tenure at Queen’s.

abstract: PhD


title: NEURONAL OXIDATIVE STRESS AND DENDRITIC TRIMMING IN A MOUSE MODEL OF LATE ONSET ALZHEIMER`S DISEASE

contributor:
Andrew, David
Biomedical and Molecular Sciences

subject: CA1, dendrite, hippocampus, morphometry, oxidative stress, pyramidal neurons, spatial memory, spines

abstract: The study of late-onset (sporadic) Alzheimer`s Disease (LOAD) has lacked animal models where the impairments develop with aging. Oxidative stress promotes LOAD, so we have developed an oxidative stress-based model of age-related cognitive impairment based on gene deletion of aldehyde dehydrogenase 2 (Aldh2). This enzyme is important for the detoxification of endogenous aldehydes, such as 4-hydroxynonenal, arising from lipid peroxidation. Previous work showed that the knockout (KO) mice exhibit a progressive decline in spatial and recognition memory compared to wildtype (WT) mice. Therefore, we searched for an underlying morphological substrate. First, morphometric analyses of pyramidal neurons using Golgi-Cox staining were performed in dorsal and ventral hippocampal CA1 (dCA1 and vCA1) as well as in overlying the primary sensory cortex in 12 month-old KO vs WT mice (Chapter 2). In 12-month old mice, the morphological results of dCA1 neurons revealed significant dendritic reductions in length, intersections, ends, and nodes in KO vs WT. Spine density along the apical dendrites is significantly reduced. In contrast the arborization in vCA1 and primary sensory cortex of KO mice showed comparatively minor reductions in branching and spine density. This specific lesion to the dorsal hippocampus helps explain spatial memory deficits in KO mice, whereas ventral hippocampal lesions cause impairments in stress and emotion. Our second study (Chapter 3) focused on the dCA1 to determine the time course of dendritic trimming over the 12 months and if it was associated with oxidative stress. No reduction in dendritic branching was detected at 3 months in KO vs WT, but by 6 months, dCA1 pyramidal arbors were dramatically cut back and remained so through 9 and 12 months. Immunostaining pyramidal cell bodies for HNE protein adducts (a marker for damage due to oxidative stress) showed small increases within dCA1 at 3 months, progressively increasing through 12 months. As with dendritic cutback, this increase was specific to dCA1, not vCA1 and only in KO mice. These findings are all in keeping with oxidative stress-associated dendritic cutback specific to our KO mice contributing to dorsal (but not ventral) hippocampal dysfunction, promoting cognitive impairment.

abstract: PhD


title: UNDERSTANDING PROCESSES, STRUCTURES AND INTER-PROFESSIONAL RELATIONAL NETWORKS WITHIN ORGAN DONATION PROGRAMS IN ONTARIO

contributor:
Tranmer, Joan
Schirmer, Janine
Nursing

subject: Organ donation programs, organ and tissue donation coordinators, program evaluation, social network analysis, nurses

abstract:
Background: The complex factors contributing to variation in the performance of organ donation programs are poorly understood. Thus, the overall aim of this dissertation research was to enhance our understanding of the organizational attributes (i.e., processes and structure) and inter-professional relationships within organ donation programs in Ontario.
Objectives: The specific research objectives were: (1) To identify and synthesize the current evidence in regards to the key contexts, processes and structures of international organ donation programs, (2) To describe the interactions of the Organ Tissue Donor Coordinators (OTDCs) with others during organ donation cases, and (3) To describe the interprofessional interactions during organ donation cases, within organ donation programs in Ontario, from an organizational perspective (structure, context, process).
Methods: To address Objective 1, I conducted a scoping review of the literature.  To address Objective 2, I completed a social network analysis (SNA) of organ donation cases focusing on the OTDC role and interactions, and to address Objective 3, I completed a mixed method SNA with a convergent design. Data were collected among 3 Ontario hospitals through interviews, review of documents, and case observation.
Results:  For Objective 1, I identified three themes that influence success in organ donation programs: context (n=39, 46 %), process (n=48, 57 %), and structural (n=59, 70%). In the social network analysis (Objective 2), OTDCs were identified as the hub facilitating the information exchange in the network.  For Objective 3, I identified that the care team regarded the OTDCs’ position as central in the network (contrary to the network analysis measures); and there were opportunities for improvement to reduce organ allocation time.
Conclusions: This thesis’ findings reinforced positive aspects, previously presented in the literature, of the benefits of the OTDC role in managing organ donation processes. Based on our findings, we identified potential organ donation process improvements that could positively impact donation rates and reduce transplant waiting lists. However, in the future, it will be important to consider a national perspective that would allow comparisons across provinces to further explore the interprofessional roles and organizational attributes that are associated with optimal performance of organ donation networks.

abstract: PhD


title: Why Are We Settling? Indigenous Cultural Safety Education for Counsellors in Ontario

contributor:
Levesque, Lucie
Kinesiology and Health Studies

subject:
Indigenous cultural safety education
counselling psychology education
mental health
First Nations, Inuit, Metis

abstract: Indigenous cultural safety education is crucial to achieving greater health equity for Indigenous Peoples (Browne et al., 2016) by helping counsellors recognize the social, historical, political, and economic context of contemporary Indigenous wellness experiences (Ramsden, 2002). Accredited graduate programs in counselling psychology are the foundation of mental health support (Department of Health, 2015). In Canada, graduates apply for certified professional membership with the Canadian Counselling and Psychotherapy Association and the ‘Registered Psychotherapist’ designation with the College of Registered Psychotherapists of Ontario (CRPO) to identify themselves as having met standards of professional practice. Counsellor education directly impacts professional practice and quality of support for Indigenous clients (Department of Health, 2015). The Truth and Reconciliation Commission of Canada (2015) report recognizes the need for cultural safety in recommendation 23(iii), which calls on all levels of government to provide “cultural competency training for all healthcare professionals.” This call is founded on evidence that client support tailored to a specific cultural context is more effective than generic client support (Griner & Smith, 2006; Allen et al., 2009; Gone, 2013). It is unknown if and to what extent counsellors trained in Ontario universities receive cultural safety education. Using Transformative Education Theory and a Reflexive Antiracism lens to understand the implementation and impact of cultural safety education in Ontario counselling professional programs, three studies were conducted: 1) An environmental scan of cultural safety education curricula across six Ontario university counselling programs; 2) Interviews with nine course instructors (one Indigenous) who teach counselling courses to examine course content, structure and delivery related to cultural safety education; and, 3) Interviews with 16 counselling students (one Indigenous) to discuss how their program experience impacts their ability to develop a culturally safe practice. Results indicate that Indigenous cultural safety education is only partially being incorporated as a core portion of counselling psychology curriculum in Ontario. Instructors took a fragmented approach to teaching about Indigenous wellness, leaving students with a fragmented understanding of how to develop a culturally safe practice. This suggests that Ontario counselling programs still have work to do in responding to Truth and Reconciliation Commission’s recommendation 23(iii).

abstract: PhD


title: On the Dynamical and Algebraic Properties of Bratteli Diagrams

contributor:
Mingo, James
Cellarosi, Francesco
Mathematics and Statistics

subject:
topological dynamics
dimension groups
irrational rotations
Bratteli diagrams
Bratteli-Vershik systems

abstract: A variety of dynamical systems, in topological and measurable settings, can be realized as Bratteli-Vershik systems. This document introduces the basic notions of Bratteli diagrams and provides detailed descriptions of Bratteli-Vershik models in both abstract and concrete settings. We also introduce the algebraic properties of Bratteli diagrams that interact with the dynamical realizations. In particular, we explore the dynamical and algebraic features of Bratteli diagrams derived from the action of an irrational rotation on the circle with a distinguished parameter that further cuts the partitions generated by the rotation.

abstract: M.Sc.


title: Crime and Punishment in the Patriarchal Court of Constantinople in Late Byzantium, 1261-1453

contributor:
Greenfield, Richard
History

subject:
Patriarchate of Constantinople
Late Byzantine History
Church History
Legal History
Patriarchal Court
Orthodox Church

abstract: The Patriarchal court was one of the two major courts in Constantinople in the Late Byzantine period together with the imperial tribunal. Although it is an ecclesiastical court per se, its jurisdiction was never clearly defined, and it gradually adjudicated more and more lay cases in addition to clerical and monastic ones. This dissertation investigates the cases of crimes, offenses, and disputes in order to better understand the jurisdictional duties of the Patriarchal court in the Late Byzantine society, state, and the Byzantine churches and monasteries. The social cases mostly concern economic issues such as credit, real estate, and business partnerships; and familial issues such as marriage, divorce, and dowry which include not just couples but also widows and children. There were several other types of social crimes and offenses such as theft, rape, and magic tried at the Patriarchal court. Among the cases related to the ecclesiastical sphere one can find simony, heresy, dissension, and sacrilege. However, the Patriarchal registers demonstrate that a good number of those cases were either political or politicized, involving either the politicians themselves or those who utilized their affiliation with politicians at the Patriarchal court to obtain a favourable decision. For this reason, this dissertation takes a trilateral approach to examine the cases: it looks at social, political and politicized, as well as ecclesiastical and monastic crimes and disputes. Several scholars since the Enlightenment period have argued that the Medieval justice system was cruel, arbitrary, and secretive, and that justice systems have steadily progressed since then. This study aims to prove that the decisions made by the Patriarchal court in the Medieval period were, to the contrary, humane, corrective, transparent, and evidence-based. The Patriarchal court also frequently aimed to rehabilitate culprits through threats and occasionally through punishments, and it strove to protect the disadvantaged in its capacity to do so to such an extent that it sometimes chose not to apply its own laws to certain culprits.

abstract: PhD


title: THE DEVELOPMENT AND VALIDATION OF A THREE-DIMENSIONAL VISUAL TARGET ACQUISITION SYSTEM TO ASSESS THE PERFORMANCE EFFECTS OF HEAD SUPPORTED MASS

contributor:
Fischer, Steven
Kinesiology and Health Studies

subject:
Fitts' Law
Head Supported Mass
Whole-Body Vibration
Human Performance
Time-optimal Head Movements

abstract:
Rotary-wing aircrew in Canada and abroad experience a myriad of occupational risk factors that contribute to neck pain. Most functional assessment approaches relevant to evaluating aircrew neck pain are too reliant on static outcome measures and do not consider scanning tasks routinely required of aircrew. The primary goal of this dissertation was to describe the development and design of the three-dimensional visual target acquisition system (3D-VTAS) to facilitate the evaluation of dynamic, fast, goal-oriented head movements using a Fitts’ task paradigm. The secondary goal was to utilize the system to explore and understand how task familiarization affects performance and test-retest reliability, how added head supported mass (HSM) affects performance, and how the combined factors of HSM and whole-body vibration (WBV) influence performance, kinematics and muscular demand.
The first study describes the development of the system, which included various system verification and validation activities. As anticipated, changes in index of difficulty appropriately influenced target acquisition time. Relative to movement planes of the head, we found that axial head rotations (yaw) produced the fastest target acquisition times compared to the sagittal plane (pitch) and two off-axis movement trajectories. After accounting for within-day familiarization, between-day test-retest reliability of the system achieved fair to excellent intraclass correlation coefficient results.
The second study reports on the influence of operationally relevant HSM (helmet and night vision goggles) on three 3D-VTAS performance outcome measures (target acquisition time, time to move off target, and error index). Compared to the unloaded condition, added load to the head degraded performance and increased the time to move off target.
The third study investigated the combined effect that operationally relevant HSM and vertical WBV have on 3D-VTAS performance, kinematics, and neck muscle activity. Exposure to WBV degraded performance. Peak muscle activity during off axis movements were consistently above 50% of maximum voluntary contraction for the right upper neck extensors; potentially indicative of muscular strain.
In general, the results of these studies illustrate the potential of the 3D-VTAS to facilitate the assessment of rapid aiming head movements and thus understand the influence of HSM and other occupational risk factors on performance and function.

abstract: PhD


title: EFFECTS OF MULTIPLE MEDICATIONS ASSOCIATED WITH QTC PROLONGATION: PREVALENCE AND OUTCOMES ASSOCIATED WITH USE AMONG OLDER ADULTS

contributor:
Seitz, Dallas
Public Health Sciences

subject:
epidemiology
arrhythmia
medication
polypharmacy
cardiac death

abstract: Medications are commonly used by older adults and can provide many benefits. However, harmful side effects may occur, particularly when multiple medications are prescribed. Prolongation of the corrected QT (QTc) interval is a disturbance in heart rhythm that can precede ventricular arrhythmia and sudden cardiac death (VA/SCD). More than one hundred medications have been linked to QTc prolongation; however, how often they are prescribed to older adults in Ontario is unknown. Effects of multiple QTc prolonging medications on adverse cardiac outcomes are also not well understood. This thesis aimed to identify how frequently QTc prolonging medications are prescribed to older adults in Ontario, identify factors associated with their use, and investigate associations between these medications and VA/SCD. A cross-sectional design was used to determine frequency of QTc medication prescriptions. Factors associated with such prescriptions were identified using logistic regression. A nested case-control design and conditional logistic regression were used to investigate exposure to known QTc risk medications and VA/SCD. Over half of the 1,912,061 older adults identified were prescribed at least 1 QTc prolonging medication; 22.9% were prescribed 2 or more. 15.8% were prescribed at least 1 known risk medication. Antidepressants and antibiotics were the most commonly prescribed known risk medications. Factors associated with these prescriptions included long-term care residence and conditions these medications are used to treat, such as infection. Exposure to prescription of QTc prolonging medications of known risk was associated with increased risk of VA/SCD (unadjusted odds ratio [OR]: 1.52, 95% confidence interval [CI]: 1.43-1.61), with higher risks among new users (unadjusted OR: 1.86, 95% CI: 1.69-2.04). This thesis increases knowledge of prescription patterns and adverse effects of QTc prolonging medications and helps identify situations in which they may be more likely to occur. Awareness of these risks will allow for appropriate prevention and intervention. Prescription strategies minimizing risks could be developed that protect those at higher risk and permit those at lower risk to take additional medications that could prove beneficial.

abstract: M.Sc.


title: Malaria prevention in eastern Myanmar

contributor:
Davison, Colleen
Public Health Sciences

subject:
malaria
insectide treated bed nets

abstract:
Background: Insecticide-treated bed-nets (ITNs) and mass drug administration (MDA) are key malaria elimination tools but their varied uptake has not been extensively explored among ethnic minority and displaced populations in Southeast Asia.
Objectives: (1) To describe prevalence of ITN possession, access, and use; (2) assess the association between biological sex of household members and ITN use and whether any such associations were dependent on age or household ITN supply; and (3) provide an overview of factors affecting uptake of ITNs and MDA in Southeast Asia.
Methods: Manuscript 1. Data from ethnic minority and internally displaced communities in eastern Myanmar was used to describe prevalence of ITN possession, access, and use. The association between a household member’s biological sex and their ITN use was assessed using multilevel log binomial regression. Age and sufficient household ITN supply were tested as potential effect modifiers.
Manuscript 2. A scoping review of academic and grey literature was conducted to provide an overview of factors influencing ITN use and individual participation in MDA programs in South East Asian countries.
Results: Manuscript 1. 89.9% (95% CI: 89.6, 90.2) of people lived in households with at least one ITN. Approximately half belonged to households with sufficient ITN supply and used an ITN. Pregnant women and children under five had the highest proportion of ITN use regardless of sufficient household ITN status. Female adults aged 15 to 49 years old (RR: 1.1, 95% CI: 1.05, 1.08) and females aged 50 years and above (RR: 1.04, 95% CI: 1.01, 1.06) were more likely to use ITNs. This relationship did not differ by sufficient household ITN status.
Manuscript 2. Determinants of ITN and MDA coverage were quite consistent across interventions and countries and related to access, knowledge of malaria, intervention knowledge, perceptions of interventions, social dynamics, affordability and incentives, and individual sociodemographic characteristics. “Social dynamics” was a unique determinant of MDA individual participation.
Conclusion: Certain subgroups were more likely to use ITNs, although overall ITN access and use remains low. Further research and interventions are needed to address gaps in ITN access and use, and MDA participation across Southeast Asia.

abstract: M.Sc.


title: Interrogating International Human Rights Law on the Rights of Free Speech and Privacy in the Digital Age:  Reconceptualizations, Reconfigurations, (Un)reasonable Limits.

contributor:
AMANI, BITA
Law

subject: International Human Rights; Privacy; Free Speech; Internet

abstract:
This dissertation offers a legal, doctrinal analysis of how deficient some critical aspects of the interpretation of the fundamental human rights of free speech and privacy in international law are, in the face of increasingly widescale infringement of these rights by both governments and corporations, in our use of the internet in this digital age. While my concern is with free speech and privacy across the digital space as a whole, in this study, I utilize the issues of surveillance and big data as the backdrop. As such, surveillance and big data are used to problematize and highlight my wider systemic concerns. With that in mind, the dissertation is meant to interrogate and discuss international free speech and privacy rights jurisprudence, against the framework of the theoretical underpinnings of these rights in the literature, in order to unpackage the gaps, problems, failings, threats or other issues, when that jurisprudence is applied to our use of the internet, or is considered in light of the overall nature of the internet. The basic question that the study therefore asks, is this – In the framework of the extreme digital age within which we now operate, how does international human rights law adjust to safeguard the fundamental rights to privacy and free speech?

Having identified a series of gaps, shortcomings and unreasonable limits in the jurisprudence, the study advances and argues for a reconceptualization and reconfiguration that puts certain normative considerations from the theoretical constructs at the forefront of the adjudication of free speech and privacy rights, in the context of the digital age in which we live. I argue that autonomy and democracy, founded on the premise of human dignity, are the key underpinnings of any such adjudication of these rights, in so far as protecting us from the emerging challenges of the digital space is concerned. The study also accepts its aspirational dimensions, bearing in mind of course, that states are politically sovereign and are not subject to any binding, universal law or institution that has coercive powers of enforcement on matters of international human rights.

abstract: PhD


title: INVESTIGATING MEASUREMENT MODALITIES FOR INTEGRATED USE IN OVERUSE INJURY RESEARCH

contributor:
Rainbow, Michael Jr
Mechanical and Materials Engineering

subject:
Biomechanics
Inertial Measurement Units
Running Gait Analysis
Ankle Biomechanics

abstract:
Running is a common form of exercise enjoyed throughout the world. Unfortunately, it poses a significant risk of injury, as up to 70% of runners suffer an overuse injury within a one-year period. Previous research indicates that three overarching factors contribute to overuse injuries in running – dosage, morphology, and movement patterns; however, the threshold of these three factors combining to result in injury is specific to each athlete, and not well understood.
To aid future research of overuse injuries, we conducted two studies using three different measurement modalities. In the first study, we used Inertial Measurement Units (IMUs) to monitor gait features of participants running on a treadmill. Using statistical parametric mapping of IMU signals, the system detected changes in strike pattern, stride length, bouncing gait, and genu valgus gait. With further validation and refinement, this system would allow for monitoring of these gait features in the wild, giving researchers greater insight into the development of overuse injuries.
The second study was a pilot study, in which we investigated motion of the tibia and relative motion of the talus and calcaneus with respect to the tibia during a hopping motion. We found that internal rotation of the talus after impact leads the internal rotation of the tibia. This grants plausibility to the theory of tibiotalar coupling – that internal rotation of the tibia is driven by that of the talus. After approximately 20% of stance, the talus moves into external rotation with respect to the tibia, and we hypothesize that it acts as a buffer to allow rotational independence between the rearfoot and tibia. Additionally, this study highlighted the inherent inter-subject variability in biomechanics studies. We have shown that there is benefit and necessity in subject-specific analysis over population-wide conclusions in biomechanics.
Finally, we discuss the implications of both studies to the future of overuse injury research. The research presented is a first step toward more comprehensive studies into overuse injury etiology. Using the approaches described, researchers may be able to use a combination of measurement modalities to encompass dosage, morphology, and movement patterns in a large-scale, prospective overuse injury study.

abstract: M.A.Sc.


title: The Role of Macrophages and the NLRP3 Inflammasome In Right Ventricular Failure in Pulmonary Arterial Hypertension

contributor:
Archer, Stephen L
Biomedical and Molecular Sciences

subject:
Pulmonary Arterial Hypertension
Right Ventricular Failure
Macrophages
NLRP3 inflammasome

abstract:
Background: Pulmonary arterial hypertension (PAH) is an obliterative pulmonary vasculopathy that results in right ventricular failure (RVF). We speculate that RVF results from inflammation due to the influx of inflammatory cells into the RV. Macrophages may contribute to PAH-RVF by activating pyrin domain-containing protein 3 (NLRP3) inflammasome, triggering cytokine release. Currently, there are no approved medications targeting PAH-RV inflammation. This work aims to assess the role of macrophages and the NLRP3 inflammasome in RVF and find effective therapeutic strategies in preclinical rat models of PAH.
Methods & Results: We studied PAH-RV inflammation in a monocrotaline (MCT) rat model, characterized by RVF and inflammation, and compared it to the pulmonary artery banded (PAB) rat model that has similar RV pressure overload and hypertrophy (RVH), but which lacks RVF. Macrophages and NLRP3 were examined in control, PAB and MCT-RV using super-resolution confocal microscopy. MCT-RV macrophages were significantly increased compared to their control; whereas, PAB-RV macrophages were not increased compared to sham. Flow cytometry was used to identify macrophages, endothelial cells and fibroblasts, and measure RV cell-specific NLRP3 expression. MCT-RV and lung macrophages were significantly increased in number compared to control, with a shift favouring M2 phenotype in the lungs. Macrophages were the main source of NLRP3 inflammasome. RV-NLRP3, caspase 1 and IL-1b content were significantly higher in MCT-RV than control. Fibrosis was significantly increased in MCT and PAB-RVs, but more severe in MCT-RV, as assessed by picrosirius stain. Cultured MCT-monocytes (±MCC950, an NLRP3 inhibitor) revealed a significant increase of NLRP3:ASC interaction, reflecting inflammasome activation, at 10-minutes post-nigericin (an NLRP3 activator). Treating MCT-rats with intraperitoneal gp130 antagonist (an inhibitor of the gp130 subunit of the interleukin-6 receptor) significantly reduced the RV macrophage count and NLRP3 inflammasome content and improved RV function without altering pulmonary vascular remodelling.
Conclusion: RV inflammation mediated by the NLRP3 inflammasome in macrophages contributes to RVF. There is greater macrophage infiltration and NLRP3 inflammasome expression and activation in MCT-RV versus PAB-RV. Blocking gp130 signalling in vivo, a mechanism critical to interleukin-6 signalling and macrophage recruitment prevents RV-macrophage accumulation and improves RV function, suggesting a new therapeutic paradigm for PAH.

abstract: M.Sc.


title: Effect of Heating Cycles on Microstructure of Dissimilar Friction Stir Welded Age-Hardenable Aluminum Alloys

contributor:
Diak, Bradley
Mechanical and Materials Engineering

subject:
Age hardenable aluminium alloys
Friction stir welding
Non-isothermal
Shercliff-Ashby
LSW
Precipitation kinetics
Dislocation recovery
Small-angle x-ray scattering
Wide-angle x-ray scattering
AA7075
AA6022
Post-weld heat treatment
Phase Field Model
Dissimilar
Precise Strain Rate Sensitivity

abstract: The effect of heating on microstructural changes in dissimilar friction stir welding of aluminum alloys AA6022 and AA7075 was studied. The challenge in welding these alloys is the strength loss in the heat affected zone (HAZ) due to the over-ageing of metastable precipitates. Isothermal ageing studies of AA6022 and AA7075 revealed apparent activation energies of 122 and 112 kJ/mol, respectively, which were used in a modified Shercliff-Ashby model incorporating non-isothermal heating to predict hardness evolution in AA7075/AA6022 lap welds. The model predicts the hardness minimum location in the weld with <15% difference between measured and predicted values, which correlates to the precipitate structure observed by transmission electron microscopy. The effect of a 180 °C, 30 minutes post weld heat treatment (PWHT), typical of automotive paint bake cycles, was further studied. The kinetics of the precipitate and dislocation microstructure evolution from PWHT was investigated in different weld regions using laboratory-based small- and wide-angle X-ray scattering (SAXS/WAXS). The precipitate volume fraction evolution determined by SAXS, for ex- and in-situ heating, reveals a fast dissolution stage in the stir zone and thermomechanical affected zones, followed by asymptotic increase, with little change in the HAZ. The measured PWHT precipitation kinetics follows the Lifshitz-Slyozov-Wagner theory, but with a monotonically decreasing rate constant of ~10^-30 m^3s^-1 compared to the analytically predicted 10^-28 m^3s^-1. New mechanisms for the rate constant reduction based on the dislocation density decrease measured by WAXS are proposed. Strain rate sensitivity measurements of the AA7075 stir zone at 294 and 78 K reveals that mechanical mixing via FSW creates a structure containing solute atoms, precipitates and dislocations that linearly contribute to strengthening, but this mixed state contains less solute than obtained by traditional solutionizing. A two-dimensional, two-particle phase-field model simulation of η phase in Al-Mg-Zn predicts a time^1/3 coarsening kinetic during PWHT, with a rate constant that matches the experimental data for the HAZ over the first 100 s only. The work illustrates that structure parameters obtained at macroscopic, mesoscopic and microscopic length scales using a combination of experimental and modeling approaches are necessary to build a predictive understanding of FSW post-weld heat treatment.

abstract: PhD


title: A NARRATIVE APPROACH TO UNDERSTANDING NURSE EDUCATORS’ EXPERIENCES OF TEACHING DISASTER NURSING TO UNDERGRADUATE NURSING STUDENTS IN ONTARIO

contributor:
Tregunno, Deborah
Nursing

subject:
Teaching Disaster Nursing
nurse educators
disaster nursing

abstract: Disasters across the globe occurring with increasing frequency and devastation require an immediate response to mitigate social and economic upheaval. Nursing plays a key role in disaster management from beginning to end: prevention, preparedness, response, and recovery. Unfortunately, nurses are unprepared to manage disasters, mainly due to a lack of knowledge and experience. Although nursing literature recommends incorporating disaster nursing (DN) education into international undergraduate nursing curricula, few studies discuss how to implement such curricula; and worse, I found no studies based in Canada even though Canadian nursing regulatory bodies require competence in DN of entry-level nurses . My study aimed to explore nursing educators’ experiences of teaching DN to help me understand what, when, and how nurse educators teach this important subject. Understanding the current practice of teaching DN helps to improve existing teaching methodologies and produce a more prepared nursing workforce. Using a qualitative narrative inquiry mainly guided by Clandinin and Connelly (2000), my research study includes the stories of two nurse educators who shared their unique experiences of teaching DN in Canadian nursing schools. Participants were interviewed twice, and data was analyzed using the three-dimensional narrative inquiry space of time, sociality, and place. While the findings of this study are consistent with the literature that DN education is taught in the community health course, findings also point to its inclusion in the context of the medical surgical course. This study also highlighted how nurse educators teach DN in Ontario, Canada, and key challenges they encounter including lack of DN knowledge, time, and teaching resources. One surprising interpretation of the narratives was the limit of educators’ knowledge and how their experience may restrict their awareness of the need to expand their DN knowledge and expertise.

abstract: MNSc.