title: The Currency of Water in Words: An Analysis of the Conceptual Metaphors of Water

contributor:
O'BRIEN, SUSIE
English and Cultural Studies

subject: Water, Metaphor, Environmental Humanities, Cultural Studies, Canadian Literature

abstract: This dissertation is a study of water metaphors in the theoretical framework of feminist environmental humanities. It draws on feminist theory, metaphor theory, and Indigenous theories. It examines some of the water metaphors enshrined in Canadian legislation, specifically the Fisheries and Oceans Act and the Canada Water Act. It also examines some of the water metaphors in Canadian literature, focusing on creative works by Lisa Moore, Rita Wong, and Leanne Betasamosake Simpson. I argue that a dialogue between metaphor theory and feminist theory radically transforms the scope for understanding water in a way that not only consolidates the presence of materiality, but initiates a trajectory into the discursive and creative modes of metaphor that enable the interrogation of the politics of water. As a settler Canadian, I position this dialogue in relation to Richard W. Hill Sr. and Daniel Coleman’s metaphor of the Two Row Wampum-Covenant Chain Treaty to frame the conversation between the Indigenous and settler Canadian texts that I examine in this dissertation. Following a reparative arc, I analyze the metaphors of water to reveal the discrepancy between some of the legislative and creative metaphors. I conclude that the analytical lens of metaphor contribute to a greater understanding of how the conceptual metaphors of water we employ reflect our embodied experience of water and how historically marginalized as well as new metaphors can shape our values and ideas about water in the Anthropocene. I also conclude that the theoretical intersection of water and metaphor constitutes a powerful foundation from which to reimagine metaphor’s shared materiality and efficacy with water. This study affirms the value of a cultural intervention in the praxis of the water issues of the Anthropocene.

abstract: Thesis

abstract: Candidate in Philosophy

abstract: In this dissertation, I examine some of the water metaphors in Canadian legislation and literature. I argue that water and metaphor follow similar architectural processes and, from a perspective of the theoretical intersection of water and metaphor, I examine how individual water metaphors reveal the way metaphors frame our thoughts and shape our behaviour towards water. I show that the metaphors of water in the Canadian legislation, such as the Fisheries and Oceans Act and the Canada Water Act, are limited whereas literary metaphors of water in creative works represent a more comprehensive reflection of the material qualities of water and of the human and more-than-human relations with water. I conclude that the analytical lens of metaphor is useful to examine our relations with water and that the environmental humanities, which are excluded from solutions of water issues, can significantly contribute to the resolution of water issues in the Anthropocene.


title: Synthesis and Reactivity of Chromium and Vanadium Complexes for Atomic Layer Deposition

contributor:
Emslie, David J. H.
Chemistry and Chemical Biology

abstract:
New vapour phase thin film deposition methods to enable manufacturing of
increasingly smaller transistors are in high demand. Atomic layer deposition (ALD) is a
thin film deposition method that yields uniquely conformal and uniform thin films
through the sequential exposure of vapour-phase reagents to a surface. Typically, two
reagents are used: (1) a metal-containing precursor complex and (2) a co-reagent which
reacts with the precursor complex to afford the target material. Any by-products of this
surface-based reactivity must be volatile, such that they can be removed by interpolated
inert gas purges. One ALD cycle consists of exposure of the surface to a precursor,
followed by an inert gas purge, followed by a pulse of co-reagent, and then a final inert
gas purge. The thin film thickness in an ideal ALD method is controlled solely by the
number of ALD cycles utilized.
Developing an ALD method requires accurate control of precursor design, so as
to achieve the required thermal stability and volatility, as well as the desired reactivity
with a chosen co-reagent. This work investigates the feasibility of using homoleptic
chromium and vanadium alkoxides as precursors for metal ALD when combined with
hydrosilanes or hydroboranes as the co-reagents. The synthesis of [Cr(OtBu)4] (1) and
[V(OtBu)4] (2) was carried out according to literature procedures, with some
modifications. Complex 1 sublimed at 25 °C (10 mTorr) and decomposed when a neat
sample was heated to 110 °C for 24 hours. Complex 2 distilled at 25 °C (10 mTorr) and
decomposed when a neat sample was heated to 110 °C (in the dark) for 24 hours.
Pinacolborane (HBpin) and phenylsilane (PhSiH3) commercial reagents were explored as
potential co-reagents through solution reactivity studies. Decamethylsilicocene (3), and 1,4-bis(trimethylsilyl)-2-methyl-2,5-cyclohexadiene (4), which were synthesized
according to literature procedures, and were also explored as potential co-reagents. The
reactions of 1 and 2 with HBpin were particularly promising, and suggested the
possibility of utilizing these reagents for the development of a new method for chromium
and vanadium metal ALD.
Additionally, chromium and vanadium complexes containing fluorinated alkoxide
ligands, perfluoro-tert-butoxide (pftb), were synthesized in an attempt to increase the
thermal stability of the precursors. [CrCl(pftb)2(THF)3] (5) and K[V(pftb)4] (6) were
crystallized from these reactions. Complex 5 could not be isolated in pure form, whereas
pure 6 was isolated in 59% yield. Complex 6 sublimed at 75-85 °C (10 mTorr) and
exhibited some decomposition when a neat sample was heated at 130 °C for 24 hours.
Complexes 5 and 6 proved to be far less reactive towards HBpin and PhSiH3 than 1 and
2. In order to determine a suitable oxidizing agent for the synthesis of the target complex,
[V(pftb)4], cyclic voltammetry was utilized to determine the oxidation potential of 6. The
E1/2 value for 60/+ was determined to be approximately 0.64 V versus [FeCp2]+/0 in 1,2-
difluorobenzene.

abstract: Thesis

abstract: Master of Science (MSc)


title: Trust and Human Challenge Vaccine Trials

title: EXAMINING THE RELATIONSHIP BETWEEN PUBLIC OPINION AND TRIAL DESIGN SELECTION

contributor:
Binik, Ariella
Sciaraffa, Stefan
Philosophy

subject:
Human Challenge Vaccine Trials
Public Trust

abstract: In a challenge trial, “healthy volunteers are intentionally exposed to pathogens in a controlled environment, in order to promote understanding of the pathogenesis, transmission, prevention and treatment of infectious diseases in humans.” (WHO 2021, Preface). Intentional infection is an uncomfortable concept, and as a result there is a widely held belief amongst research ethics scholars and commentators that a significant ethical concern with challenge trials is their potential to negatively impact the public’s trust in the institution of medical research (Eyal 2022, 4). However, the relationship between public trust and the ethics of conducting and assessing challenge trials is complex and existing literature on the subject does not sufficiently clarify it. This paper will begin by examining the ethical permissibility of challenge trials. Once these trials are shown to be ethically permissible under particular circumstances, I will explore how concerns about the way these trials allegedly exacerbate public mistrust largely result from ambiguities in the terms ‘public’ and ‘trust’. After both terms are defined, I will formulate my own account of how public trust should apply to a risk/benefit analysis for the purpose of trial design selection called the community engagement account, which argues that trial design selection policy should focus on demonstrating trustworthiness rather than garnering trust. Because demonstrating trustworthiness requires meeting a set of known expectations, this account identifies local, specific publics as those whose expectations should be of concern when discussing public trust and trial design selection. To examine the expectations of these publics, this account defends community engagement as the measure which should be used to acquire evidence of harmful public mistrust towards the institution of science that could potentially result from conducting a challenge trial.

abstract: Thesis

abstract: Candidate in Philosophy

abstract: In a challenge trial, “healthy volunteers are intentionally exposed to [diseases] in a controlled environment,” to give researchers a better understanding of a disease in order to develop cures or preventative measures for it (WHO 2021, Preface). Many research ethics scholars believe that conducting challenge trials could negatively impact the public’s faith in the institution of medical research, but the relationship between public trust and conducting challenge trials is complex and existing literature on the subject does not sufficiently clarify it. This paper begins by exploring whether or not challenge trials can be ethically conducted. Once I show that they can be under particular circumstances, I examine how public trust concerns largely result from the fact that ‘public’ and ‘trust’ are not well defined. After defining them, I formulate my own account of how public trust should apply to a risk/benefit analysis for the purpose of trial design selection.


title: Identifying Suitable Turtle Overwintering Habitat Through the Integration of Thermal, Chemical and Physical Wetland Properties

contributor:
Waddington, Dr. James Michael
Earth and Environmental Sciences

subject: Ecohydrology, Turtle overwintering, species at-risk habitat, conservation

abstract: Turtles are among one of the most vulnerable vertebrates on the planet and within Canada, all eight native species of freshwater turtle are designated as at-risk under COSEWIC. The primary extinction risk turtles face is the loss of their habitats. At the northern limit of their range, turtles rely on the presence and persistence of aquatic habitats to survive the winter. In the face of unprecedented climate and land-use changes, identification of key overwintering habitat attributes is crucial because relatively little is known about how they interact to optimize overwintering habitat suitability. We measured in-situ thermal, chemical and physical conditions at Blanding’s turtle overwintering sites within wetlands in the Georgian Bay Biosphere Mnidoo Gamii to (1) characterize available overwintering habitat, (2) test for overwintering habitat selection by Blanding’s turtles and (3) quantify the turtle resilience zone (RZ). We measured water and sediment temperatures, dissolved oxygen (DO), water,  ice and snow depth at 5 (2020-2021) and 19 (2021-2022) Blanding’s turtle overwintering locations and four paired available microhabitats (floating mat, inflow, lagg, open water) across 5 wetlands. Blanding’s turtles selected average daily temperatures that ranged from 3.58°C to 0.53°C with a mean of 1.08°C, minimum average DO observed was 1.10 mg/L and average water and ice depth ranged from 42cm to 79cm, 12cm to 38cm, respectively. Based on habitat use data, we quantified the RZ as present when aquatic habitats had temperatures between 0 and 4°C, DO ≥1 mg/L and minimum water depth of 40 cm. Using the RZ we identified suitable overwintering habitats within our study region and found that the RZ varied across wetlands and microhabitats. Overall, the RZ is a powerful tool that can be used to identify suitable overwintering sites which can directly contribute to conservation and management strategies for at-risk turtles.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Turtles are among one of the most vulnerable vertebrates on the planet and within Canada, all eight native species of freshwater turtle are designated as at-risk under the Committee on the Status of Endangered Wildlife in Canada. The primary extinction risk turtles face is the loss and degradation of their habitats. Turtles located in northern temperate regions use aquatic habitats that provide specific temperatures, dissolved oxygen, and water depths during overwintering. We characterized available overwintering habitat and combined aquatic temperatures, dissolved oxygen and water depth into a single metric, the resilience zone (RZ), to quantify overwintering habitat suitability. We found that Blanding’s turtles actively selected specific overwintering conditions. This is the first study to quantify the turtle RZ and we found that overwintering habitat was already limited within a pristine landscape. Finally, our results show that the RZ can directly contribute to conservation and management strategies for at-risk turtle species.


title: Mitonuclear interactions and the origin of macaque society

contributor:
Evans, Ben
Biology

subject:
Macaca
female philopatry
dispersal
natural selection
behavior

abstract:
In most eukaryotes, aerobic respiration requires interactions between autosomally-
encoded genes (Ninteract genes) and mitochondrial DNA, RNA, and protein. In species
where females are philopatric, contrasting distributions of genetic variation in mito-
chondrial and nuclear genomes creates variation in mitonuclear interactions that may be
subject to natural selection. To test this expectation, we turned to a group with extreme
female philopatry: the macaque monkeys. We examined four genomic datasets from (i)
wild caught and (ii) captive populations of rhesus macaque, which is the most widely
distributed non-human primate, and (iii) the stump-tailed macaque and (iv) a subspecies
of longtail macaque, both of whose mitochondrial DNA is introgressed from a highly di-
verged ancestor. We identified atypically long runs of homozygosity, low polymorphism,
high differentiation and/or rapid protein evolution associated with Ninteract genes com-
pared to non-Ninteract genes. These metrics suggest a subset of Ninteract genes were
independently subject to natural selection in multiple species. Selection on mitonuclear
interactions is thus a factor in macaque genome evolution that could have influenced as-
pects of macaque societies including species diversity, ecological breadth, female-biased
adult sex ratio and demography, sexual dimorphism, and mitonuclear phylogenomics.

abstract: Thesis

abstract: Master of Science (MSc)


title: Nonlinear Optical Phenomena in Hybrid TeO2-Si3N4 Waveguides

contributor:
Bradley, Jonathan
Engineering Physics

abstract: Over the last few decades nonlinear integrated optical devices have emerged as an enabling technology for a number of important applications in communications, computing, sensing, medical, and defense and security systems. It all has been possible through the advancement of micro and nano-fabrication techniques and the development of nonlinear optical materials that can leverage the mature complementary metal-oxide semiconductor (CMOS) infrastructure. Among the materials explored for integrated nonlinear photonics silicon nitride (Si3N4) is one of the most suitable and widely used. Despite its maturity and prominence, there are a few challenges that persist. One of them is the difficulty in the fabrication of thick low-loss Si3N4 waveguides suitable for nonlinear applications using conventional wafer-scale methods. In particular, a waveguide thickness of at least 700 nm is needed to attain anomalous dispersion which is critical for efficient nonlinear processes. However, fabricating such waveguides through the preferred method of low-pressure chemical vapor deposition is challenging due to cracks developing during deposition caused by the differences in tensile stress between the Si3N4 layer and substrate. Tellurium oxide (TeO2) is among the oxide glasses with the most attractive optical properties. TeO2 has a relatively large linear refractive index, wide transparency, high nonlinearity, high Raman gain, high acousto-optic figure of merit, negligible nonlinear losses, and high rare earth dopants solubility making it a good candidate for linear, nonlinear, and active optical devices. This work presents a study of nonlinear optical phenomena in a hybrid TeO2-coated Si3N4 platform. The platform is based on a thin commercial foundry Si3N4 which avoids the need for customized fabrication processes and highly nonlinear TeO2 that is deposited at a low temperature by reactive radio frequency magnetron sputtering which is compatible with back-end-of the line CMOS processing. Importantly, the required anomalous dispersion is attained by adding the TeO2 coating which also helps to enhance waveguide nonlinearity owing to its higher nonlinearity than Si3N4.  In addition, the TeO2 can host rare-earth dopants for waveguide amplifiers and lasers, offering the potential for monolithic linear, nonlinear, and active functionalities in the same platform. Chapter 1 presents an overall discussion on material platforms that have been studied for integrated nonlinear photonics in comparison to Si3N4 and TeO2. Chapter 2 covers the theoretical background of nonlinear optics, discusses the main nonlinear processes, nonlinear integrated devices under study, and their applications, and introduces the hybrid TeO2-Si3N4 platform. Chapter 3 presents an analytical and numerical study on waveguide nonlinearity enhancement and dispersion engineering. The results presented show enhancement of the nonlinear parameter for TeO2-Si3N4 waveguides of up to three times that of stoichiometric Si3N4 and calculated anomalous dispersion at near-infrared wavelengths for 400-nm Si3N4 coated with varying TeO2 thicknesses. Chapter 4 provides an experimental proof-of-concept for the hybrid TeO2 on a 400-nm-thick Si3N4 platform as a candidate for monolithic linear, nonlinear and active photonic circuits. Dispersion measurements results are presented showing anomalous dispersion for a 400 nm thick, 1.6 µm wide Si3N4 strip waveguide coated with a 424 nm TeO2 film, with values of ⁓25 and ⁓78 ps/nm∙km at 1552 nm for the fundamental transverse electric and transverse magnetic modes, respectively. Microring resonator frequency combs with up to 8 comb lines covering a 1000-nm wavelength span for a pump power of 251 mW coupled into the bus waveguide are presented. Multimode lasing and a net gain of 2.8 dB in an Er-doped TeO2-coated Si3N4 microdisk resonator and a 6.7 cm long paperclip waveguide, respectively, are also reported.  Chapter 5 presents experimental results on supercontinuum generation where an octave-spanning supercontinuum covering wavelengths from 940 to 1930 nm is demonstrated at a low peak pump power of just 258 W for 100 fs pulses centered at 1565 nm. Chapter 6 covers a comprehensive analytical and numerical study of Raman amplification in the hybrid platform. The results are promising and show high potential for on-chip Raman amplification at reasonable powers, device footprint, and lower losses that can be reached by improving fabrication methods and waveguide designs. For example, for a projected loss of 0.01 dB/cm which is lower than our current figure but higher than the state-of-the-art Si3N4 loss a net gain of up to 10 dB is shown for 1 W pump power in a 1.3 m long TeO2-coated Si3N4 spiral waveguide. Chapter 7 summarizes and discusses the results presented and provides propositions for future work.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: PROGNOSTIC MODELS OF CLINICAL OUTCOMES AND PREDICTIVE MODELS OF TREATMENT RESPONSE IN PRECISION PSYCHIATRY

contributor:
Kapczinski, Flavio
Neuroscience

subject:
precision psychiatry
individualized predictive modeling
psychotic disorders
treatment response
data-driven biomarkers

abstract: In this thesis, we developed prognostic models of clinical outcomes, specific to violent and criminal outcomes in psychiatry, and predictive models of treatment response at an individual level. Overall, we demonstrate that evidence-based risk factors, protective factors, and treatment status variables were able to prognosticate prospective physical aggression at an individual level; 2) prognostic models of clinical and violent outcomes in psychiatry have largely focused on clinical and sociodemographic variables, show similar performance between identifying true positives and true negatives, although the error rate of models are still high, and further refinement is needed; 3) within treatment response prediction models in MDD using EEG, greater performance was observed in predicting response to rTMS, relative to antidepressants, and across models, greater sensitivity (true positives), were observed relative to specificity (true negatives), suggesting that EEG prediction models thus far better identify non-responders than responders; and 4) across randomized clinical trials using data-driven biomarkers in predictive models, based on the consistency of performance across models with large sample sizes, the highest degree of evidence was in predicting response to sertraline and citalopram using fMRI features.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: Uncovering mechanisms behind microbiota-induced neuroprotection in C. elegans models of Alzheimer’s disease

contributor:
MacNeil, Lesley
Biochemistry and Biomedical Sciences

abstract:
Alzheimer’s Disease (AD) is the most common neurodegenerative disorder
worldwide. The risk of developing AD is influenced not only by genetic factors, but also the environment. The multi-factored pathogenesis that leads to AD development poses a challenge for identifying causal factors that promote or protect against neurodegeneration. We use Caenorhabditis elegans as a model of AD to measure the impact of human microbiota species on AD-related phenotypes. The two hallmarks of AD are amyloid-β (Aβ) plaques and neurofibrillary tangles composed of the protein tau. Using a C. elegans model overexpressing Aβ, we identified a group of Enterobacteriaceae species that significantly reduce paralysis. To validate these findings, we used another C. elegans model that pan-neuronally expressed aggregate-prone tau (AP-tau). We observed decreased neurodegeneration in response to most of the same bacteria protective against Aβ-induced paralysis, providing additional evidence of microbiota-promoted neuroprotection. To explore the underlying host mechanisms, we examined gene expression changes in animals exposed to neuroprotective bacteria. Numerous biological processes were differentially regulated in response to the neuroprotective microbiota species, including innate immunity, stress responses, and protein phosphorylation. Several C. elegans orthologs of human tau tubulin kinase genes, TTBK1 and TTBK2, were downregulated in response to neuroprotective microbiota species. RNAi-mediated knockdown of C. elegans ttbks sufficiently induced neuroprotection in AP-tau animals. Further, Enterobacter caused decreased abundance of a tau species phosphorylated at S422, a TTBK1 direct phosphorylation site. These findings suggest that species from the human microbiota can reduce tau phosphorylation, and mediate neuroprotection through downregulation of ttbk. Overall, by studying the impact of the human microbiota on models overexpressing Aβ or AP-tau, we have uncovered a potential mechanism by which microbiota-mediated neuroprotection can occur. In doing so, we also gain a greater understanding of conserved pathways involved in gene-environment interactions promoting development of AD.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: Alzheimer’s Disease (AD) is the most common neurodegenerative disorder in the world. Causes and preventions of AD are difficult to find because many things affect neurodegeneration. For example, resident gut bacteria can change brain health. To study this, we use Caenorhabditis elegans worms as animal models that display traits of AD. C. elegans eat bacteria, have a nervous system, and share many genes with humans. We identified bacteria from the human microbiota that improved neuron health in C. elegans AD models. We examined C. elegans gene expression, and found a group of genes, tau tubulin kinases (TTBKs), were shut down by these bacteria. Removal of the TTBK gene from C. elegans improved nervous system health. Since we observed that TTBK is shut down in response to the microbiota, and loss of TTBK improves neuron health, we have found new evidence for how the microbiota can promote a healthier nervous system.


title: The Gut Microbiota’s Effect on Sociability in Fruit Flies

contributor:
Dukas, Reuven
Psychology

abstract: Social behaviour is defined as interactions between conspecifics. One facet of it, sociability, involves non-aggression interactions between conspecifics. Little research has investigated the genetics of sociability; more emphasis has been placed on its modulation by the environment. One component of the environment that has been of particular interest is the gut microbiome. Prior research indicates that the gut microbiome likely affects the behaviour of hosts via local manipulation and as an offshoot of metabolic processes, via potential channels including the vagus nerve and the immune system. The effect of the gut microbiome on social behaviour has mostly been investigated using rodent models. Fruit flies would be a useful model, given the simplicity of their gut microbiome and protocols to manipulate to it. There has been insufficient research on gut microbiome modulation of social behaviour in fruit flies (Drosophila melanogaster). We investigated the effects of the gut microbiome on adult fly sociability by generating germ-free wild-type flies and raising them on a germ-free food medium. After housing the flies in mixed-sex groups for 72 hours, we scored their sociability using a sociability assay developed in the Dukas lab at McMaster University. We found that germ-free females were more sociable than control females.  A follow-up experiment did not confirm this effect. We postulate that this inconsistency in the results may have been due to reasons such as variation in food quality and atmospheric conditions, or a lack of robustness in the effects of microbes on sociability. Future work in this area would benefit from access to better-regulated microbial work facilities, and should focus on simulating environmental variation in diet and atmospheric conditions to discern its impacts on fly social behaviour.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Many things in our internal and external environments can affect our social behaviours, including our gut microbiome. The gut microbiome could potentially affect social behaviours by interacting with the immune and nervous systems. Research has investigated the link between social behaviours and the gut microbiome in rodents mostly, but fruit flies are simple enough to be useful for this work. We worked with fruit flies to see how the gut microbiome affects sociability, a type of social behaviour that involves non-aggressive interactions with others. We removed the gut microbiomes of developing flies, and evaluated their sociability as adults. At first, we found that females without microbes were more sociable than normal females, but did not see this upon testing again. This difference could have been due to atmospheric and diet variations in the two experiments, and future research should see if these factors can affect social behaviours in flies.


title: Deep Learning Classification and Model Explainability for Prediction of Mental Health Patients Emergency Department Visit

title: Emergency Department Resource Prediction Using Explainable Deep Learning

contributor:
Doyle, Thomas E.
Electrical and Computer Engineering

subject:
Deep Learning
Transfer Learning
Natural Language Processing
Readmission Prediction
Emergency Department Visit
Questionnaire
Patient Reported Outcome Measure
PROM
NLP
Explainability
Artificial Intelligence
Machine Learning

abstract: The rate of Emergency Department (ED) visits due to mental health and drug abuse among children and youth has been increasing for more than a decade and is projected to become the leading cause of ED visits. Identifying high-risk patients well before an ED visit will enable mental health care providers to better predict ED resource utilization, improve their service, and ultimately reduce the risk of a future ED visit. Many studies in the literature utilized medical history to predict future hospitalization. However, in mental health care, the medical history of new patients is not always available from the first visit and it is crucial to identify high risk patients from the beginning as the rate of drop-out is very high in mental health treatment. In this study, a new approach of creating a text representation of questionnaire data for deep learning analysis is proposed.  Employing this new text representation has enabled us to use transfer learning and develop a deep Natural Language Processing (NLP) model that estimates the possibility of 6-month ED visit among children and youth using mental health patient reported outcome measures (PROM). The proposed method achieved an Area Under Receiver Operating Characteristic Curve of 0.75 for classification of 6-month ED visit. In addition, a novel method was proposed to identify the words that carry the highest amount of information related to the outcome of the deep NLP models.  This measurement of word information using Entropy Gain increases the explainability of the model by providing insight to the model attention.  Finally, the results of this method were analyzed to explain how the deep NLP model achieved a high classification performance.

abstract: Dissertation

abstract: Master of Applied Science (MASc)

abstract: In this document, an Artificial Intelligence (AI) approach for predicting 6-month Emergency Department (ED) visits is proposed. In this approach, the questionnaires gathered from children and youth admitted to an outpatient or inpatient clinic are converted to a text representation called Textionnaire. Next, AI is utilized to analyze the Textionnaire and predict the possibility of a future ED visit. This method was successful in about 75% of the time. In addition to the AI solution, an explainability component is introduced to explain how the natural language processing algorithm identifies the high risk patients.


title: Patient and clinician experiences of post-discharge virtual care following non-elective surgery: A qualitative descriptive study

contributor:
Carter, Nancy
McGillion, Michael
Nursing

abstract: Remote patient monitoring (RPM) and virtual care is a burgeoning field, with considerable uptake within chronic medical populations and recently expanding to include surgical populations. Patient and clinician experiences of participating in at-home, postoperative RPM or virtual care interventions are not well described in the current literature. The objective of this study was to understand the experience of patients and clinicians who participated in a 30-day RPM and virtual care program following non-elective surgery at the beginning of the COVID-19 pandemic in Canada. The study also aimed to identify ways to improve postoperative RPM programs for future interventions. Qualitative descriptive methodology was used to describe the participants experiences of the phenomena in everyday language. Purposive, maximum variation sampling was used to recruit a heterogenous sample that included participants from all five sites of the trial and focused on recruiting patients with prior surgery. Forty-three participants (21 patients, two patient spouses, 10 nurses, 10 physicians) took part in semi-structured telephone interviews, approximately 30 minutes in length. Data was transcribed by an independent transcriptionist and confirmed by the researcher. Reflexive thematic analysis was employed, and analysis was completed by the primary researcher and triangulated with two additional researchers, guided by the Conceptual Model for Telehealth Nursing. Themes generated include: ‘Virtual care is valued and holistic care, at home’, ‘From a wide scope towards a refined intervention’, and ‘A shared responsibility: Significance of interdisciplinary collaboration’. Postoperative RPM and virtual care provides an opportunity for patients to recover at home with skilled clinical oversight, with patients and clinicians highlighting reassurance and access to clinicians during a vulnerable period, particularly within the context of the COVID-19 pandemic. Improvement for the future may include more patient-centred scheduling for interventions including reduced video calls and vital signs measurements.

abstract: Thesis

abstract: Master of Science (MSc)


title: Vaccine Hesitancy and Institutional Credibility Pre-COVID-19

contributor:
McLaughlin, Neil
Sociology

subject:
vaccines
trust in science
vaccine hesitancy
sociology of science
trust in institutions
MMR-autism
social movement
sociology of expertise

abstract:
This dissertation is an examination of trust in vaccine science, with a focus on ideas about vaccination outside the scientific consensus. It is grounded in empirical research, including 35 interviews and a review of publicly available documents, books, and academic articles. Theoretically, it is informed by theories in the sociology of science, social movements, and the sociology of expertise. In substantive chapters, it investigates the origins of the modern ‘anti-vaccine’ movement, the spread of the movement's ideas in different sociocultural and political contexts, and the perspectives and personal experiences of those who are part of the movement. Overall, it contributes to a growing body of literature that aims to change the conversation around vaccine hesitancy from an information-deficit problem to an issue about trust in institutions.

The dissertation is organized into three main papers. The first is an analysis of a specific historic episode, namely the 1998 MMR (measles, mumps, rubella) vaccine-autism controversy. I find that institutional incentive structures unintentionally circulated misinformation about the MMR vaccine by former medical doctor Andrew Wakefield and posit the role that academic reward structures have in fostering public trust. The second paper examines vaccine hesitancy with a social movement lens, specifically focusing on the strategies used by the anti-vaccine movement to organize and frame their message. I introduce the concept of an ‘anti-scientific intellectual movement’ to understand the increasing trend of social groups opposing science as a set of institutions. The third paper is a study of the lived experiences of participants who were interviewed in 2019 about their views on vaccination and how their individual experiences and meaning-making activities impacted their trust in vaccine science. I find strong distrust in scientific institutions, a desire for open dialogue and debate, and dissatisfaction with the ‘anti-vaccine’ label which participants felt erased the nuance in their perspectives. Altogether, this dissertation makes significant contributions to ongoing discussions about the public face of science and how to effectively engage with public audiences to build trust.

abstract: Dissertation

abstract: Candidate in Philosophy


title: Development of Mucoadhesive Thermogels for Treating Anterior Ocular Conditions

contributor:
Sheardown, Heather
Chemical Engineering

subject:
thermogel
inferior fornix
anterior ocular conditions
mucoadhesion
enzymatic degradation
cystinosis

abstract: Most marketed formulations for treating anterior ocular conditions are topical, with conventional eyedrops representing the most utilized modality. However, due to the natural clearance mechanisms of the eye, less than 5% of an applied dose remains bioavailable following administration. To overcome the shortcomings associated with conventional eyedrops, a series of enzymatically degradable, mucoadhesive thermogels were developed. Thermogels can be applied as a solution, like a conventional eyedrops, but gel against the heat of eye. To avoid obstructing vision, these thermogels were designed to be instilled within the inferior fornix of the eye. In these studies, the base thermogelling polymer (pNAM) was crosslinked with the natural polymer chitosan. Not only does crosslinking strengthen the typically weak thermogels, but chitosan can be enzymatically degraded by lysozyme, the highest concentration protein found in tear fluid. Therefore, the developed thermogels can be applied to the inferior fornix and degrade over multiple days. A limitation of applying materials to the inferior fornix is they tend to be poorly retained. To anchor the developed thermogels within the inferior fornix, the mucoadhesive properties were tailored based on the chitosan utilized as well as the inclusion of a disulfide monomer capable of covalently bonding with the natural mucosal layer covering the surface of the eye. The disulfide bridging monomer could be further conjugated with therapeutic components which were released as a function of mucosal interaction. Conjugates investigated included cysteamine for treating cystinosis, n-acetyl cysteine for treating dry eye, the adhesion peptide RGDC as a model peptide/protein, and polyethylene glycol for modulating material properties. The release of the drugs Ketotifen Fumarate, for treating allergic conjunctivitis, and atropine, for treating myopia, were also investigated. The safety of the developed thermogels were studied both in vivo and extensively in vitro utilizing both rat and rabbit models.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: Topical eyedrops are the most utilized treatment option for the vast majority of ocular diseases. However, eyedrops are largely ineffective with less than 5% of an applied dose reaching the desired cite of action. Therefore, eyedrops need to be frequently reapplied. To overcome these limitations, an eyedrop was developed which can be applied as a liquid but gels against the heat of the eye. This gel allows for prolonged drug release over multiple days, greatly increasing drug efficacy as well as patient comfort and compliance. To prevent obstructing vision, these gels can be applied under the lower eyelid. To keep these gels retained under the lower eyelid, they were designed to anchor to the natural mucus layer which covers the surface of eye. The developed eyedrops represent a significant advancement in ocular care; bettering the convenience, comfort, and effectiveness for patients of a topical formulation compared to traditional eyedrops.


title: How does policy support guideline implementation? The role of policy, political, and health systems considerations in clinical practice guideline implementation

title: Policy support in guideline implementation

contributor:
Lavis, John N.
Health Policy

subject:
Policy
Clinical Practice Guidelines
Implementation science

abstract: Clinical practice guidelines (CPGs) provide recommendations based on the best available evidence to ensure that decisions about patient care are well-informed. Extensive research within implementation science has highlighted the factors and strategies that are most important in CPG implementation across a variety of settings. The uptake of evidence-based practice however, is quite complex, and there still exist gaps in knowledge about how those factors and strategies are affected by the policy context. In particular, we know little about how considerations about the role of policy, politics, and health systems affect whether and how CPGs are used. The objective of this dissertation is to advance the use of policy, political, and health systems considerations in the implementation of CPGs through three original scientific contributions. First, a critical interpretive synthesis of existing literature was used to enrich two existing implementation frameworks (the Knowledge-to-Action Framework and the Consolidated Framework for Implementation Research) from a policy context perspective. Second, a multiple explanatory case study of guideline implementation processes was used to investigate how the enriched frameworks could be used to identify policy context-related factors and strategies needed to support CPG implementation. Third, a formative evaluation study design was utilized to explore how to improve upon and support the use of these enriched frameworks from the perspective of expert guideline developers and guideline implementers across the six World Health Organization regions. Collectively, these studies contribute theoretical, substantive, and methodological insights toward understanding the policy context relevant factors and strategies that support effective implementation of CPGs. A better understanding of the policy, political, and health systems considerations that impact CPG implementation can translate into more fit-for-purpose CPGs being developed and more tailored implementation strategies being employed, as well as more patients benefiting from clinical care informed by the best available evidence.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Clinical practice guidelines (CPGs) help guide clinicians incorporate into their existing practice the best ways to treat patients, and they do so by providing recommendations based on the best available research evidence. There is research evidence about what factors are important and what approaches are effective in making sure CPGs are used, but there is a lack of understanding about how those factors and strategies are affected by the policy context. This thesis answers questions about the role of the policy context in CPG implementation to help fill this gap. It accomplishes this in three ways: 1) it enriches two existing implementation frameworks with policy context considerations; 2) it explores how these enriched frameworks could have helped with two past implementation efforts; and 3) it provides insights from guideline experts about how to improve upon and support the use of these enriched frameworks.


title: Chronic Pain as a Continuum: Autoencoder and Unsupervised Learning Methods for Archetype Clustering and Identifying Co-existing Chronic Pain Mechanisms

title: Chronic Pain as a Continuum: Unsupervised Learning for Identification of Co-existing Chronic Pain Mechanisms

subject:
Unsupervised Learning
Chronic Pain
Semi-supervised Learning
Co-existing Chronic Pain Mechanism
Overlapping Clustering
Autoencoder
Chronic Pain as a Continuum
Chronic Pain Quantification
Machine Learning
Artificial Intelligence

abstract:
Chronic pain (CP) is a personal and economic burden that affects more than 30% of the world's population. While being the leading cause of disability, it is complicated to diagnose and manage. The optimal way to treat CP is to identify the pain mechanism or the underlying cause. The substantial overlap of the pain mechanisms (i.e., Nociceptive, Neuropathic, and Nociplastic) usually makes identification unreachable in a clinical setting where finding the dominant mechanism is complicated. Additionally, many specialists regard CP classification as a spectrum or continuum.

Despite the importance, a data-driven way to identify co-existing CP mechanisms and quantification is still absent. This work successfully identified the co-existing CP mechanisms within a patient using Unsupervised Learning while quantifying them without the help of diagnosis established by the clinicians. Two different datasets from different cohorts comprised of patient-reported history and questionnaires were used in this work. Unsupervised Learning (k-prototypes) revealed notable overlaps in the data. It was further emphasized by the outcomes of the Semi-supervised Learning algorithms when the same trend was observed with some diagnosis or class information. It became evident that the CP mechanisms overlap and cannot be classified as distinct conditions. Additionally, mixed pain mechanisms do not make an individual cluster or class, and CP should be considered as a continuum.

To reduce data dimension and extract hidden features, Autoencoder was used. Using an overlapping clustering technique, the pain mechanisms were identified. The pain mechanisms were also quantified while elucidating overlaps, and the dominant CP mechanism was successfully pointed out with explainable element. The hamming loss of 0.43 and average precision of 0.5 were achieved when considered as a multi-label classification problem.

This work is a data-driven validation that there are significant overlaps in CP conditions, and CP should be considered a continuum where all CP mechanisms may co-exist.

abstract: Thesis

abstract: Master of Applied Science (MASc)

abstract: Chronic pain (CP) is a global burden and the primary cause for patients to seek medical attention. Despite continuous efforts in this area, CP remains clinically challenging to manage. The most effective method of treating CP is identifying the underlying cause or mechanism, which is often unattainable. This thesis attempted to identify the CP mechanisms existing in a patient while quantifying them from patient-reported history and questionnaire data. Unsupervised Learning was used to identify clinically meaningful clusters that revealed the three main CP mechanisms, i.e., Nociceptive, Neuropathic, and Nociplastic, achieving acceptable hamming loss (0.43) and average precision (0.5). The results exhibited that the CP mechanisms co-exist and CP should be regarded as a continuum rather than distinct entities. The algorithm successfully indicated the dominant CP mechanism, a goal for optimal CP management and treatment. The results were also validated by a comparative analysis with data from another cohort that demonstrated a similar trend.


title: A Large-Scale Neighborhood Search Algorithm for Multi-Activity Tour Scheduling Problems

contributor:
Huang, Kai
Computational Engineering and Science

abstract: In this research, we study multi-activity tour scheduling problems with heterogeneous employees in a service sector where demand varies greatly during the day. This problem relates to assigning the employees’ working days throughout the planning horizon and working periods on each working day. In each period, an activity type is given which requires certain skill of the employees. The goal is to reduce the overall over- and under-coverage for each period and activity. The shifts and breaks defined with variable starting slots and durations make the problem flexible and hard to solve. In order to address the problem, an integer programming (IP) approach is first proposed. Due to the problems’ high degree of flexibility, it is impossible to solve instances involving numerous employees and activities in a timely and efficient manner. This leads to the proposal of a heuristic method based on a large neighborhood search (LNS) algorithm. We first create the daily schedules by a context-free grammar (CFG). Then we solve a resource-constrained shortest path problem (RCSPP) to create weekly schedules. Heuristic search is performed on weekly schedules. Moreover, when a constraint on task repetition is added, a CFG is unable to express this constraint, so we incorporate an extension of the IP into our proposed algorithm. Importantly, our approach does not use any closed-source commercial solver like CPLEX. Computational experiments are carried out on the industrial and randomly generated instances to evaluate the performance of the IP solved by CPLEX and the proposed algorithm. Results reveal that our method outperforms CPLEX in both solution time and solution quality in larger instances.

abstract: Thesis

abstract: Master of Science (MSc)


title: Therapeutic Cannabis Use for Sleep and Mental Health

contributor:
Frey, Benicio
Neuroscience

subject:
therapeutic cannabis
sleep
mental health
symptom management
insomnia
depression
anxiety

abstract:
Introduction: The evolving global landscape around cannabis regulation has renewed interest in exploring the therapeutic potential of cannabinoids for several medical conditions. Of these conditions, sleep and mental health concerns are often reported among the most common reasons for therapeutic cannabis use. In this work, we investigated the patterns and profiles of cannabis use in naturalistic samples to better understand its use for the management of sleep and mental health symptoms. We focused our examination on insomnia, depression, and anxiety, as cannabis is most often used to manage these conditions.

Results: Across our studies, cannabis was generally perceived to be efficacious for the management of insomnia symptoms in various mental health conditions. Analyses of strain categories revealed differences in perceived symptom improvement between strains for some conditions. In individuals with insomnia, indica-dominant and indica hybrid strains were found to reduce insomnia symptom severity more than cannabidiol (CBD) strains and sativa-dominant strains. Among individuals managing insomnia symptoms in depression, indica-dominant, indica hybrid, and sativa-dominant strains were perceived to be more efficacious than CBD strains. An additional investigation of several mental health conditions revealed pre-symptom severity, age, gender, and the ratio of CBD to THC as the factors most strongly associated with symptom change following cannabis use. Distinct patterns of cannabis response were also observed between individuals with insomnia, depression, and anxiety.

Conclusion: Our research investigating cannabis use for insomnia symptom management suggests that across conditions, individuals may perceive symptom improvements with cannabis use. Our subsequent work on cannabis use for mental health suggests that symptom profiles may have a role in the perceived effects of cannabis. These results highlight the therapeutic potential of cannabis-based products for sleep and mental health; however, the generalizability of this work is limited due to potentially biased samples of cannabis users who may have been more likely to perceive cannabis as effective. Our findings further emphasize the need for placebo-controlled investigations that can assess the safety and efficacy of cannabinoid treatments for general therapeutic use.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: Recent changes to worldwide cannabis policies have led to cannabis use becoming more common. Among individuals who use cannabis to manage medical conditions, many report sleep and mental health as the main reasons for use. While more individuals are turning to cannabis for therapeutic use, very little is known about how it is used and what effects it may have. For our research, we examined large databases of cannabis users to understand patterns of cannabis use for sleep and mental health. We also investigated how individuals with the most frequently reported mental health concerns (insomnia, depression, and anxiety) reported feeling after cannabis use. We found that individuals who used cannabis for insomnia symptoms, with or without another mental health concern, reported general improvements in sleep. Some types of cannabis were also reported to work better than other types of cannabis. In addition, we found unique patterns in how individuals with insomnia, depression, or anxiety reported feeling after cannabis use. Although our overall results may seem positive, more research is needed to specifically understand how cannabis works, and whether it can be used safely for sleep and mental health conditions.


title: Development of an Indoor Positioning System for Smart Aging Applications

contributor:
Fang, Qiyin
Biomedical Engineering

subject: Smart Home, Indoor Positioning, Aging in Place

abstract: The development of an Indoor Positioning System that requires a non-invasive setup and installation process is outlined in this dissertation. The Hardware, Mechanical and Software components are described in complete detail. The system operates using a hybrid of Bluetooth Low Energy (BLE) signal strength analysis and proximity sensor data collection to determine the location of a known Bluetooth compatible device. Additionally, a dynamic remote calibration protocol was developed to ensure a safe and smooth setup and integration process in any location the system is implemented. The system uses custom designed beacon modules that connect directly to outlets in designated rooms. These beacons relay sensor and BLE data to a Hub module that collects and stores all this data locally and on a cloud server. These features ensured that the IPS is a completely remote device that can be setup independently by the user. To our knowledge, this is the only Indoor Positioning System that does not require prior knowledge of the location of integration and the need for an in-person setup and calibration process. Additionally, despite the lack of an extensive setup and calibration process the system still operates at an accurate room detection percentage of 98%. To further prove its ease of use the system has been implemented in a clinical study where several older adults (65+) have integrated this system within their homes. This system has been designed to act as the foundation for larger scale healthcare monitoring applications.

abstract: Thesis

abstract: Candidate in Philosophy

abstract: Indoor positioning technology acts as the foundation for several healthcare monitoring networks. An accurate and easy to use indoor positioning system will entail how effective the overall healthcare monitoring platform is. Additionally, indoor positioning itself can be accomplished in several different ways. Some of these approaches include the use of physical sensors to detect presence, signal strength approximations via some sort of communication protocol or even the use of secure entry via RFID identification tags. Currently, most of the systems that use one of these approaches require extensive setup and calibration processes and extensive knowledge of the tracking locations. However, this is not always practical especially when the system is integrated in a large-scale environment like a retirement home. A system with an easy- to-use setup and installation platform is needed to complete these high impact healthcare monitoring projects.


title: DEVELOPING HIGH-PERFORMANCE GeTe AND SnTe-BASED THERMOELECTRIC MATERIALS

contributor:
Mozharivskyj, Yurij
Chemistry and Chemical Biology

subject:
Thermoelectric
Density functional theory
Band Engineering
Defect Engineering

abstract:
This dissertation covers the study of the thermoelectric properties of GeTe and SnTe. The goal of this research is to develop high-performance lead-free thermoelectric materials that can replace PbTe-based systems so that thermoelectric technology could be bring into real application. During the study, extensive investigations on the electrical and thermal transport behaviors were conducted both experimentally and theoretically.
	In Chapter 1 ~ 3, the origin of thermoelectricity, modelling and characterization methods are discussed in detail. In Chapter 4, study on the thermoelectric properties of Bi, Zn and In co-doped GeTe was presented. Initial doping with Bi enhanced the performance by tuning the electronic properties and bringing down the thermal conductivity. Subsequent Zn doping permitted to maintain the high power factor by increasing carrier mobility and reducing carrier concentration. Subsequent In doping boosted the density of state effective mass. A peak zT value of 2.06 and an average zT value of 1.30 have been achieved in (Ge0.97Zn0.02In0.01Te)0.97(Bi2Te3)0.03. In Chapter 5, we thoroughly investigated the transport properties of SnTe-Sb2Te3 alloying system, provided useful insight of the mechanism of the enhanced Seebeck coefficient. To also overcome the poor carrier mobility, Pb compensation was performed which effectively optimized the carrier mobility. Meanwhile, Pb compensation broke the charge balance, allowing Sb to precipitate out of the structure. These second-phase particles provided additional source of phonon scattering, effectively suppressing the lattice thermal conductivity. As a result, a peak zT of 1.1 at 778K and an average zT of 0.56 from 300K to 778K was achieved in (Sn0.98Ge0.05Te)0.91 (Sb2Pb0.5Te)0.09, which is one of the best SnTe-based thermoelectric systems.

abstract: Thesis

abstract: Master of Science (MSc)

abstract:
Thermoelectric materials can generate energy from temperature gradient, making them potential solutions for the escalating energy crisis. The state-of-the-art thermoelectric material is PbTe which shows outstanding performance and high stability. However, the toxicity of Pb element limits its practical application.
	It is the purpose of this work to develop high-performance GeTe and SnTe-based thermoelectrics to reduce the usage of PbTe. Combining theoretical calculations and experimental characterizations, detailed investigation on the transport properties, crystal structure and microstructure were performed on both GeTe and SnTe. Relations between their thermoelectric properties and their composition, synthesis method and microstructure were revealed. This work paves the path for the development of environmentally friendly and high-performance thermoelectric systems.


title: An analysis of complex trait variation using Drosophila melanogaster

contributor:
Dworkin, Ian
Biology

subject:
complex traits
quantitative genetics
drosophila melanogaster
genotype-phenotype map
bioinformatics
multivariate statistics

abstract: Complex traits are traits which vary quantitatively along a normal distribution. Their variation is influenced by many loci throughout the genome, each contributing a small fraction to trait heritability. Complex traits are also shaped by gene-gene interactions between focal alleles with genetic modifiers, as well as gene-environment interactions. In this thesis, I study complex traits from multiple angles using Drosophila melanogaster as a model system. First, the relationship between variation in gene expression in developing wing tissue and variation in adult wing shape is assessed, where the complex trait in question is wing shape. Using gene wise multivariate linear models, I show that at the level of natural variation, no single gene’s variation in expression has a “significant” effect on variation in wing shape. When genes are grouped into functional categories using Gene Ontology (GO) terms, I show that not only can the signal of effect be recovered, but also that genes from within a GO term group have similar effects on wing shape even when accounting for correlations in gene expression between genes. I also study gene expression and trait expressivity and penetrance under a complex trait framework. An sd/vg allelic series is used to study the joint effect of genetic background and the magnitude of allelic perturbation on global gene expression in the developing wing tissue. I show that global transcriptional variation is largely correlated with wildtype genetic background, and not with strength of perturbation as might have been expected. Further, variation in cell shape or cell size are shown to be candidate mechanisms contributing to background-dependent phenotypic variation, and specific genes are suggested for follow-up functional analysis.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Complex traits, like height for example, are difficult to study. Their variation is influenced by the small effects of many genes throughout the genome, by gene- environment interactions, and by gene-gene interactions. In this thesis, I explore complex trait variation using Drosophila melanogaster. First, I examine the relationship between variation in gene expression in developing wing tissue and variation in adult wing shape, where the complex trait in question is wing morphology. I also examine gene expression itself as a complex trait and study how its variation is affected by gene-gene interactions and genetic perturbation. Overall, I present a novel way of modelling the relationship between gene expression variation and wing shape variation. I also show that global gene expression variation is in large part correlated not with genotype, as expected, but with genetic background, and that changes in cell size or shape may underlie background-dependent phenotypic effects.


title: The Impact of Infant Sex on Perinatal Outcomes Following Exposure to Multiple Courses Versus a Single Course of Antenatal Corticosteroids: A Secondary Analysis of the MACS Randomized Controlled Trial

contributor:
McDonald, Sarah
Health Research Methodology

subject:
antenatal corticosteroids
infant sex
preterm birth
perinatal health
secondary analysis of an RCT

abstract:
Objective:
Animal literature has suggested that the impact of antenatal corticosteroids (ACS) may vary by infant sex. Our objective was to assess the impact of infant sex on the use of multiple courses versus a single course of ACS and perinatal outcomes.
Study Design:
We conducted a secondary analysis of the Multiple Courses of Antenatal Corticosteroids (MACS) for Preterm Birth trial. Our primary outcome was a composite of perinatal mortality or clinically significant neonatal morbidity (including neonatal death, stillbirth, severe respiratory distress syndrome, intraventricular hemorrhage [grade III or IV], cystic periventricular leukomalacia, and necrotising enterocolitis [stage II or III]). Secondary outcomes included individual components of the primary outcome as well as anthropometric measures. Baseline characteristics were compared between participants who received multiple courses versus a single course of ACS. Multivariable regression analyses were conducted with adjustment for pre-defined covariates including an interaction between exposure to ACS and infant sex.
Results:
Data on 2304 infants were analyzed. The interaction term between treatment status (multiple courses versus a single course of ACS) and infant sex was not significant in the adjusted model for the primary outcome (p=0.86), nor for any of the secondary outcomes. Exposure to multiple courses versus a single course of ACS was not associated with the primary outcome either before or after adjustment (aOR 0.99, 95% CI 0.67 to 1.45, n=2292 infants). However, exposure to multiple courses versus a single course of ACS resulted in significantly lower birth length (p=0.02) and head circumference at birth (p=0.04) although not birthweight (p=0.06).
Conclusions:
Infant sex did not modify the association between exposure to ACS and perinatal outcomes including perinatal mortality or neonatal morbidity or anthropometric outcomes. However, animal literature indicates that sex specific differences after exposure to ACS may emerge over time and thus investigating long-term sex-specific outcomes warrants further attention.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Antenatal corticosteroids (ACS) are given in pregnancies at risk of early birth. ACS help the lungs and other organs, such as the brain and kidneys to mature. ACS help improve babies’ survival and reduce the risk of other health complications. Several animal studies suggest that infant sex can affect long-term outcomes after receiving a higher dose of ACS. The goal of our study was to look at the effect of infant sex on the relationship between the use of multiple courses (i.e., a higher dose) versus a single course of ACS and short-term outcomes. These outcomes include challenges with breathing, bleeding in the brain, problems in the bowel, and infant death. Our study found that infant sex did not significantly change the relationship between ACS and short-term infant outcomes, but further study is required on long-term outcomes as sex specific differences may emerge over time as reported in animal literature.


title: State Estimation and Thermal Fault Detection for Lithium-Ion Battery Packs: A Deep Neural Network Approach

contributor:
Emadi, Ali
Electrical and Computer Engineering

subject:
Lithium-ion battery
Battery safety
Deep Neural Network
Artificial intelligence
Battery thermal model

abstract:
Recently, lithium-ion batteries (LIBs) have achieved wide acceptance for various energy storage applications, such as electric vehicles (EVs) and smart grids. As a vital component in EVs, the performance of lithium-ion batteries in the last few decades has made significant progress. The development of a robust battery management system (BMS) has become a necessity to ensure the reliability and safety of battery packs. In addition, state of charge (SOC) estimation and thermal models with high-fidelity are essential to ensure efficient BMS performance.
The SOC of a LIB is an essential factor that should be reported to the vehicle’s electronic control unit and the driver. Inaccurate reported SOC impacts the reliability and safety of the lithium-ion battery packs (LIBP) and the vehicle. Different algorithms are used to estimate the SOC of a LIBP, including measurement-based, adaptive filters and observers, and data-driven; however, there is a gap in feasibility studies of running these algorithms for multi-cell LIBP on BMS microprocessors. On the other hand, temperature sensors are utilized to monitor the temperature of the cells in LIBPs. Using a temperature sensor for every cell is often impractical due to cost and wiring complexity. Robust temperature estimation models can replace physical sensors and help the fault detection algorithms by providing a redundant monitoring system.
In this thesis, an accurate SOC estimation and thermal modeling for lithium-ion batteries (LIBs) are presented using deep neural networks (DNNs). Firstly, two DNN-based SOC estimation algorithms, including a feedforward neural network (FNN) enhanced with external filters and a recurrent neural network with a long short-term memory layer (LSTM), are developed and benchmarked versus an extended Kalman filter (EKF) and EKF with recursive least squares filter (EKF-RLS) SOC estimation algorithms. The execution time of EKF, EKF-RLS, FNN, and LSTM SOC estimation algorithms with similar accuracy was found to be 0.24 ms, 0.25 ms, 0.14 ms, and 0.71 ms, respectively. The DNN SOC estimation algorithms were also demonstrated to have lower RAM use than the EKFs, with less than 1 kB RAM required to run one estimator.
The proposed FNN and LSTM models are also used to predict the surface temperature of different lithium-ion cells. These DNN models are shown to be capable of estimating temperature with less than 2 ⁰C root mean square error for challenging low ambient temperature drive cycles and just 0.3 ⁰C for 4C rate fast charging conditions. In addition, a DNN model which is trained to estimate the temperature of a new battery cell, is found to still have a very low error of just 0.8 ⁰C when tested on an aged cell.
Finally, an integrated physics, and neural network-based battery pack thermal model (LP+FNN) is developed and used to detect and identify different thermal faults of a LIBP. The proposed fault detection and identification method is validated using various thermal faults, including fan system failure, airflow lower and higher than setpoint, airflow blockage of submodule and temperature sensor reading faults. The proposed method is able to detect different cooling system faults within 10 to 35 minutes after fault occurrence. In addition, the proposed method demonstrated being capable of detecting temperature sensor reading offset and scale faults of ±3 ⁰C and ±0.15% or more, respectively with 100% accuracy.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Examining cognition in a wild fish species with multiple male phenotypes

contributor:
Kolasa, Jurek
Alonzo, Suzanne H
Biology

subject:
cognition
fish
alternative reproductive tactics

abstract: Research on numeracy, social preferences, and personalities in fishes has contributed to our understanding of the underlying mechanisms and evolution of cognition in animals. Research on fish cognition has been mainly conducted on domesticated, lab-acclimated, or lab-based strains freshwater fish species and a handful of marine fish species. My project explores cognition, specifically memory and individual recognition, in a wild-living Mediterranean marine fish with male alternative reproductive tactics (ARTs): nesting, satellite, and sneaker males. ARTs in this species change over the lifetime of an individual male, rather than by being determined by a genetic polymorphism. Males change in physiology, gene expression, hormone levels and suites of behaviour as they transition through these phenotypes. During the reproductive season, I captured wild-living fish and ran lab-based forced-choice assays to assess their response to a novel object and conspecifics. In a forced-choice assay for familiar versus unfamiliar conspecific females, I found that, nesting males preferred to spend more time with familiar conspecifics but that satellite males made more side switches, a measure of assessment or exploratory behaviour, than nesting males.  A forced-choice assay for a familiar versus unfamiliar object revealed no differences in preferences but focal females were significantly faster to explore than sneaker males. In a group size choice assay, all three male types and focal females preferred to spend time with larger groups of conspecific females. These results show that individual recognition and numerical abilities are present in this species. This work contributes to the field of fish cognition by highlighting differences in cognition in a wild-living species with multiple male phenotypes.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Our understanding of the underlying mechanisms and evolution of cognition in animals has been furthered by research on numeracy, social preferences, and personalities in fishes. Research on fish cognition has been conducted mainly on domesticated, lab-acclimated, or lab-based strains of freshwater fish species. My project explores cognition in the context of behavioural plasticity in a wild-living marine fish with three male alternative reproductive tactics: nesting, satellite, and sneaker males. In the field, I used well-established behavioural assays to examine differences in memory, individual recognition, exploration and basic numerical abilities across these three male types. This work contributes to the field of fish cognition by not only adding a wild-living species, but also in a species where we can compare cognition across multiple male phenotypes.


title: Seasonal trends in phosphorus export from three major Canadian Lake Erie tributaries

contributor:
Chow-Fraser, Pat
Biology

subject: Phosphorus, Soluble Reactive Phosphorus, Tile Drainage, Seasons, Loading, Eutrophication

abstract: The re-appearance of algal blooms in Lake Erie in recent decades has been attributed to increased loading of bioavailable phosphorus (soluble reactive phosphorus; SRP) in US tributaries, a trend linked to agricultural practices, tile drainage, and climate change. Here, we explore P-loading trends for three major Canadian tributaries of the Canadian Lake Erie Basin (CLEB) and investigate if increased loading can be related to increased use of tile drainage. Our results confirm that SRP loading from the Canadian tributaries has been increasing over the past decade in the late winter early spring, and that tile drainage is a significant driver of SRP across all seasons. However, the effects of tile drainage are not consistent across all regions where climate conditions, soil characteristics and agricultural management practices vary. This study highlights the complexity of P transport via tile drains and underscores why no single solution should be applied to manage P across the CLEB.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: he re-appearance of algal blooms in Lake Erie in recent decades has been attributed to increased loading of bioavailable phosphorus (soluble reactive phosphorus; SRP) in US tributaries, a trend linked to agricultural practices, tile drainage, and climate change. Here, we explore P loading trends for three major Canadian tributaries and investigate if increased loading can be related to increased prevalence of tile drainage. Our results confirm that SRP loading from the Canadian tributaries has been increasing over the past decade in the late winter early spring, and that tile drainage is a significant driver of SRP across all seasons.


title: Digital Twin Placement for Minimum Application Request Delay with Data Age Targets

contributor:
Zhao, Dongmei
Electrical and Computer Engineering

subject:
Digital Twins
Application data age targets

abstract:
Digital Twins are softwarized mirrors of physical systems. They can represent their
corresponding physical counterparts in real-world applications and reflect the behavior
of the latter under different scenarios with decent accuracy. In this thesis, we consider
the case where an application requests data from multiple digital twins, each representing
a physical system. The digital twins are hosted on execution servers located between
the application and the set of physical devices. Each digital twin has to be periodically
updated by its physical system and uses a portion of the execution server’s computing
resource to refresh itself. Due to the scarcity of computation resources of the execution
servers, in this thesis, we have tackled the problem of optimal digital twin placement
onto a limited set of execution servers. We are aiming at minimizing the latency of the
digital twins’ responses to the application’s requests while keeping the age of information
of served data below a certain threshold. We first formulate the problem as an integer
quadratic program (IQP) and then transform it into a semidefinite program (SDP).
We prove that the problem is NP-complete and propose polynomial-time approximation
algorithms that solve the problem with different trade-offs between the accommodation
of the application’s request latency and the achievement of data age targets.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: DESIGN OF BIOCOMPATIBLE ASPARAGINE-GRAPHENE OXIDE  FREE CHLORINE SENSORS FABRICATED USING SOLUTION BASED PROCESSING

contributor:
Deen, Jamal
Electrical and Computer Engineering

subject: Biodegradable, Chlorine, electrochemical, sensors, solution, fabrication

abstract:
Chlorine is used as a powerful disinfectant in water-related industries and in the food industry to
remove bacteria and other harmful contaminants. We present a solution-based fabrication
process for a biodegradable electrochemical free chlorine sensor using asparagine that is
functionalized onto graphene oxide (GO). An ink solution of the GO functionalized with
asparagine was fabricated then deposited onto a screen-printed carbon electrode (SPCE) using a
spin-coater. The sensor showed high a sensitivity of 0.30 μA ppm−1 over a linear range of 0 to 8
ppm with a hysteresis-limited resolution of 0.2 ppm, very high selectivity in the presence of
commonly interfering ions, and an operating voltage well below the reduction potential of
dissolved oxygen. The sensor response time to achieve a steady state was 50 s, and it showed
little change in its drift response over 16 h and over a temperature range of 10 to 45 °C. From the
development of the free chlorine sensor, over 9000 datapoints were collected and used for
training a neural network model to quantify and characterize factors affecting the free chlorine
sensor performance. A readout system was designed with a printed circuit board and an android
app to simplify free chlorine sensing for an end user.

abstract: Thesis

abstract: Master of Applied Science (MASc)

abstract:
Free chlorine is used to disinfectant sources of water, and eliminate pathogens. The World
Health Organization (WHO) maintains strict amounts of free chlorine in water due to its
widespread usage owed to its low cost and persistence in water systems. Too little, and it will not
be an effective disinfectant, and too much and the high consumption of free chlorine increases
the risk cancer or the formation of hazardous chemicals. Recently, free chlorine sensors that
measure an electrical response proportional to the amount of free chlorine are gaining interest for
fast, accurate, and repeatable measurements.
This thesis focuses on the design, fabrication, and evaluation of these sensors made using
biodegradable materials in a solution-based fabrication processes with the aim of working
towards large-scale fabrication of a printable ink. First, we review the results achieved by the
sensors within recent literature. Second, we present the design of a sensor that aims to achieve
environmentally friendly goals and maintain competitive performance characteristics. The, the
sensor is tested under various conditions with its performance quantified under different
conditions. Third, the sensor is characterized using a neural network to measure its performance
and identify sources of improvement for future designs. Finally, we incorporate the sensor with
an android app to measure free chlorine in remote water systems.


title: Reciprocity and Trust in Political Deliberation: An Investigation into the Norms of Discursive Civility

contributor:
Sciaraffa, Stefan
Philosophy

subject:
political philosophy
civility
reciprocity
trust
political polarisation
affective polarisation

abstract:
Much contemporary political discourse in the US and industrialized west is defective.
According to a number of scholars, such as Scott Aikin and Robert Talisse, this defectiveness can plausibly be explicated in terms of a breakdown in political civility. In this thesis, I scrutinize possible explanations for why incivilities are widespread in political discourse. My goal is to defend an explanation according to which citizen incivility in political discourse is blameless. To do this, I appeal to a principle of reciprocity.
According to the principle of reciprocity, citizens are not required to maintain civility in political discourse if they have reason to believe that their interlocutors will not reciprocate civility. When applied to contemporary politics, this principle implies that ordinary citizens in democratic societies across the US and industrialised west are often justified in being uncivil in political debate. For these citizens often have no reason to believe that their interlocutors will be civil. If the reciprocity principle is right, then policies aimed at restoring civility in political discourse must be concerned to build citizen trust that others will reciprocate civility. Without this trust, citizens may not see themselves as having reason to be civil.
The thesis is divided into two chapters. In chapter 1, I defend the justificatory account of incivility against two competing accounts of political incivility—identity and group theories. These accounts pathologize political incivility as a kind of irrationality, but based on the argument from reciprocity, I argue that political incivilities are often rational and so justified. In chapter 2, I analyse the kind of trust that is necessary to build more civility in political discourse. In particular, I develop and defend a conception of deliberative trust, which is defined as the belief that one’s interlocutor will reciprocally adhere to the norms of civility.

abstract: Thesis

abstract: Master of Arts (MA)

abstract:
In this thesis, I scrutinize possible explanations for why incivilities are widespread in
contemporary political discourse. By appeal to a principle of reciprocity, my ultimate goal is to defend an explanation according to which citizen incivility in political discourse is blameless. According to the principle of reciprocity, citizens are not required to maintain civility if they have reason to believe that their interlocutors will not reciprocate civility in political discussion. Based on this principle, I argue that ordinary citizens in democratic societies across the US and industrialised west are often justified in being uncivil in political debate. For these citizens often have no reason to believe that their interlocutors will be civil. If the justificatory account of incivility is on the right track, then policies aimed at restoring civility in political discourse must be concerned to build citizen trust that others will reciprocate civility. Without this trust, citizens may not see themselves as having reason to be civil in political debate.


title: Purinergic Regulation of Neurogenesis Following Spinal Cord Injury in Danio Rerio

contributor:
Scott, Angela
Biology

subject:
Spinal Cord Injury
Purinergic Signaling
P2X7
Neurogenesis
Zebrafish
Proliferation
Radial Glia
Regeneration

abstract: In contrast to mammals, adult zebrafish undergo successful neural regeneration following spinal cord injury (SCI). Radial glia (RG) lining the zebrafish central canal undergo injury-induced proliferation and subsequent neuronal differentiation to replace damaged cells and restore motor function. However, the molecular mechanisms that underlie these processes remain elusive. Here, we demonstrate that signaling through the evolutionarily conserved purinergic P2X7 receptor is involved. Within the zebrafish spinal cord, P2X7 receptors have widespread distribution with specific localization to neurons and radial glia. At the protein level, the predominant P2X7 receptor isoforms in zebrafish did not include the full-length variant expressed throughout the murine central nervous system, but two truncated splice variants. In response to SCI, protein expression of the 50 kDa isoform became downregulated at 7 dpi and returned to basal levels of expression at 14 and 21 dpi when compared to naïve controls. Meanwhile, expression of the 37 kDa isoform did not change following injury. Pharmacological activation of P2X7 following SCI resulted in a greater number of proliferating cells around the central canal by 7 dpi, while P2X7 inhibition appeared to have no effect. At 14 dpi, these treatments did not have a significant effect on the number of neurons within the injured spinal cord. This data indicates that P2X7 receptor activation is sufficient to induce cellular proliferation, but not a necessary mediator of either proliferation or neurogenesis following SCI in adult zebrafish. Our findings suggest that unlike in humans, P2X7 signaling may not play a maladaptive role following SCI in adult zebrafish.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Spinal cord injury in mammals causes widespread neuronal cell death and paralysis. In comparison, zebrafish regenerate damaged neurons and restore motor function. Radial glial cells within the zebrafish spinal cord maintain stem-cell properties. Following injury, these cells divide and replace motor neurons. Since mammals have similar cell-types within the spinal cord, understanding the molecular cues driving this adaptive response is of great interest. Here, we examined the evolutionarily conserved purinergic signaling system and found that the expression of the P2X7 receptor varies significantly from mammals and promotes radial glia division following injury.


title: Development of a Comprehensive Mobility Discharge Assessment Framework for Older Adults Transitioning from Hospital-To-Home Through Evidence Synthesis and e-Delphi Process

contributor:
Dal Bello-Haas, Vanina
Rehabilitation Science

subject:
Mobility
Older adults
Hospital-to-home transition
Aging
Discharge
e-delphi process
Scoping reviews
Qualitative content analysis

abstract:
Functional status independently predicts older adults’ hospital readmission. Despite this, clinicians often do not complete mobility assessments during the hospital-to-home transition for older adults, mainly because factors within the seven mobility determinants have not been comprehensively represented in mobility measures.
Phase 1 of this PhD thesis (manuscripts 1, 2 and 3) comprised a series of scoping reviews that comprehensively described factors within each of the seven mobility determinants [cognitive, financial, environmental, personal, physical, psychological and social] and their association with self-report and performance-based mobility outcomes. A total of 772 largely cross-sectional articles published in 51 countries were reviewed which identified 84 factors: cognitive (n=8), psychological (n=18), social (n=9); personal (n=11), environmental (n=17), financial (n=3), and physical (n=18), and their association with mobility outcomes.
Phase 2 of this PhD thesis (manuscripts 4, 5 and 6) was an e-Delphi study aimed at prioritizing and achieving consensus on mobility factors across the seven determinants considered critical to include in the Comprehensive Mobility Discharge Assessment Framework (CMDAF) for older adults transitioning from hospital-to-home. Sixty international experts (seven older adults, nine family caregivers, 24 clinicians and 20 researchers) from nine countries prioritized 43 out of 91 factors across all the seven determinants to be included in the CMDAF, except for financial determinants. Experts provided reasons for their ratings. They conditionally placed importance on certain factors over other factors based on the uniqueness of each older adult; healthcare roles and practice-based approaches; and service availability and regional [context] meaning of some of the factors. The positive and negative role of factors influencing mobility was another reason experts rated the way they did.
This is the first step in developing CMDAF. Future research should examine how and which measurement instruments best measure these 43 mobility factors to advance the CMDAF. Further examining the feasibility and practicality of using CMDAF in hospital-to-home clinical transition settings is recommended.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Mobility problems lead to hospital readmission of older adults (60 years and older). However, healthcare workers often do not assess older adults' mobility prior to discharge home. This is why this research project was done. In Phase 1 of this PhD project, 84 factors that negatively or positively influenced mobility of older adults were identified by searching the literature. In Phase 2 of this PhD project, 60 people (seven older adults, nine family caregivers, 24 clinicians, and 20 researchers) rated and agreed upon the mobility factors critical to assess when older adults are being discharged home. They reached agreement on 43 factors; and provided their reasons for choosing these factors. Reasons included that each older adult is unique, and healthcare roles and practices differ. Identifying these 42 factors is the first step. Therefore, future research should determine the tools to measure the 43 factors and test how they can be used in clinical practice.


title: Technical Activity, the Geographic Milieu, and the Art of Composition

contributor:
Allen, Barry
Steizinger, Johannes
Philosophy

subject: Philosophy Technology

abstract: This work was made with the intention of opening up a path to discovery of technical activity’s potential for emancipation once we free technical activity from the reductive shackles of labour. I utilize the philosophy of Gilbert Simondon throughout the work to build upon his theory of technics and individuation. I begin with the acknowledgement that technical activity plays an expressive role beyond that of mere work, utility, and needs fulfilment. From there, we explore the inventive aspect of technical activity and draw parallels between technical individuation and individuation within nature, which gives us a more robust definition of technical invention. Honing in on the co-constitutive relationship between organisms and environment we find a rich vocabulary of mutual formation and operation which we can translate into technical realm. True technical activity should be able to cut across organic-nonorganic lines, being able to take stock of the communicative aspects of all systems under consideration. A theory of technical composition is needed in order to think more clearly of the relations between these disparate domains, and there is no better concept than that of musical counterpoint to aid us in this task.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Instabilities in Protoplanetary Disks and Their Effects on Planetesimal Formation in the Low Turbulence Limit

title: Planetesimal Formation in Weakly Turbulent Protoplanetary Disks

contributor:
Wadsley, James
Physics and Astronomy

abstract:
This thesis uses hydrodynamic simulations to explore the properties of protoplanetary
disks in the limit of weak turbulence and small particles. It characterizes the nature
of the Kelvin-Helmholtz instability that is expected after the initial settling phase in
disks containing small grains. These disks generate levels of turbulence consistent with
observations. Values of the Shakura-Sunyaev turbulence parameter α are extracted
directly from the simulations and are found to be approximately α = 2.7 × 10−5. The
implications of high and low values of α on planet formation are investigated, showing
that planets can still form in disks with weak turbulence. We explore the associated
constraints on planet formation and how they may affect the formation of planets at
different radii within plausible planet forming disks.

abstract: Thesis

abstract: Master of Science (MSc)


title: Temporal and Landscape Influences on the Bee Community Assemblage of the McMaster Research and Conservation Corridor

contributor:
Dudley, Susan
Biology

abstract:
In recent years the issues surrounding pollinator conservation and pollinator decline has
been brought to the forefront of both the public and government. Declines are multifaceted and pollinator conservation and restoration tends to focus on open ecosystems, such as prairie and meadow habitats, where there exists a large body of research on the benefits of restoring such habitats for pollinators. However, this does not address the other ecosystems that pollinators can be found in and what critical role those habitats may play in the lifecycles of those species. I surveyed the bee and wasp community present in the Dundas Valley Region of Hamilton in southern Ontario, Canada across 5 distinct habitat types; open fields, forest edges, forests, forested groundwater fed springs, and wetlands. The abundance and richness of floral resources within these habitats and what role this might play at different times of the year was also surveyed. 10 focal species, belonging to 6 genera were chosen as a subset of the population to test for habitat use and movement on the landscape. I found that all habitat types were utilized by bees and wasps to varying degrees, depending on species, time of year, and resource availability. Males and females of the same species did not necessarily utilize the same habitats at the same time of year and there was clear evidence of population movement between these areas and habitat preference. Showing the clear need for a “big picture” approach to pollinator conservation and a need to move away from the standard restoration practice of simply creating open meadows and prairies. This does not address the diverse and heterogeneous habitat requirements needed over the course of their life cycles. Conservation efforts should focus on diversifying the types of habitats being restored on the landscape and recognizing the importance of existing remnant natural features that may add to the heterogeneity of the landscape and to the benefit of pollinator communities.

abstract: Thesis

abstract: Master of Science (MSc)


title: Characterizing the pro-survival function of the cutA growth arrest specific gene in quiescent chicken embryo fibroblasts

abstract: Genes expressed during quiescence, known as growth arrest specific (GAS) genes are of great interest due to their ability to prevent a cell from proliferating while enhancing its survivability by maintaining lipid homeostasis amongst other varied mechanisms. In response to nutritional stress, GAS genes may be upregulated, leading to quiescence instead of differentiation or senescence, implying that they are markers of quiescence. A GAS gene of particular interest is cutA. Gene profiling studies investigating gene signatures that are upregulated in response to quiescence inducing environments showed cutA to have a 50-fold increase in expression, one of the strongest responses to contact inhibition from the 28,000 genes that were analyzed. First characterized in Escherichia coli, as a divalent cation tolerance protein, cutA has a highly conserved trimeric structure across species, indicating a potentially fundamental role in cells. In this study, we confirmed the induction of cutA expression in response to oxygen depleted (hypoxia, contact inhibition) conditions that induce cellular quiescence, as well as in response to metal addition. We investigated the effect of aberrant cutA expression on cell proliferation and survival in quiescence by shRNA-mediated downregulation of the gene, which revealed that cutA does have a function in promoting cell survival in quiescence. Based on our findings, we propose a mechanism for the transcriptional activation of cutA in response to quiescent, and in response to metal addition.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: First characterized in Escherichia coli as a divalent cation tolerance protein, cutA has since been found to have a highly conserved trimeric structure and has been implicated in various different roles across species. Its characterization in eukaryotes, however, is not well defined. Gene profiling done by the Bedard Lab identified it as a gene that is found upregulated in density-arrested chicken embryo fibroblasts (CEF). In this study, we characterize its expression in reversible growth arrested CEF, as well as investigate its role in promoting cell survival in this state.


title: Competent or Warm? Applying the Stereotype Content Model to Investigating the Relationship Between Job Performance and Workplace Aggression

contributor:
Schat, Aaron
Business Administration

subject:
Workplace Aggression
Job Performance
Social Network Analysis
Envy
Contempt

abstract: This dissertation aims to advance our understanding of workplace aggression by developing and testing two models based on the stereotype content model (SCM) and adopting the social network analysis approach.  Specifically, two studies of the dissertation focus on (a) unfavorable social evaluations stemming from competence stereotypes, (b) stereotype-driven negative emotions as a mechanism to explain the relationship between competence and workplace aggression, and (c) the role of informal workplace relationships in predicting workplace aggression.  Study one investigates the nonlinear relationship between job performance and exposure to workplace aggression and two distinct mediating mechanisms at high and low levels of job performance.  High performers provoke jealousy, and low performers provoke contempt from coworkers, both of which are positively associated with exposure to workplace psychological aggression.  The study tested these relations using data from a sample of 187 teachers from educational institutions in India and found support for the curvilinear relationship between performance and workplace psychological aggression and the mediating mechanisms of jealousy and contempt for high and low performers, respectively.  Study two examines the role of workplace social ties (advice and friendship ties) in predicting workplace aggression.   Results from data collected at 2-time points from 248 individuals in 21 workgroups largely supported the proposition that highly competent employees become victims of covert aggression and low competence employees become victims of overt aggression.  Interestingly, the findings suggest that advice-giving and friendship ties mitigate the experience of aggression by reducing coworkers’ envy.  However, advice-seeking aggravates overt aggression by increasing coworkers’ contempt.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)