title: Exploring the use of Twitter and the #ShoutYourAbortion Hashtag in How Women Confront and Challenge Abortion Stigma

subject:
abortion
abortion stigma
feminist standpoint theory
critical discourse analysis
abortion discourse
pro-choice

abstract: Despite the fact that one in three women of reproductive age will have an abortion there continues to be stigma surrounding those who have had abortions. Abortion stigma continues to permeate how women are treated and services are provided. The present study explores the ways in which women use the online social networking site Twitter to engage with the #ShoutYourAbortion hashtag to resist dominant pro-life discourses of abortion and challenge abortion stigma. Through the use of a critical discourse analysis that utilizes feminist standpoint theory, four major discourses were identified as emerging out of the #ShoutYourAbortion hashtag. First, the discourse of resisting and challenging pro-life rhetoric emerged in that women utilized the hashtag to challenge dominant discourses on abortions by sharing their own experiences that contradict pro-life narratives. Second, the discourse of emphasizing the importance of choice and autonomy regarding women’s reproductive rights and freedoms was highlighted, and the importance of abortion as a form of healthcare was emphasized. Next, women used discourses that aimed to critique and challenge the abortion industry as a whole.  Lastly, women used the hashtag to normalize abortions in an attempt to challenge abortion stigma. This exploratory research provides insights into the utility of engaging with hashtags to resist and challenge dominant discourses, and how women are sharing their experiences in an attempt to change the narratives around abortion.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: Efficient Smoothed Particle Hydrodynamics Modelling of Tuned Liquid Dampers

contributor:
Tait, Michael
Civil Engineering

abstract:
The tuned liquid damper (TLD) is used to reduce the motion of many tall structures around the world. A TLD consists of a partially filled tank of liquid located near the location of maximum structural response. Due to the nonlinear behavior of sloshing liquids, a suitable nonlinear model must be employed for proper TLD design. Existing models typically have limitations on liquid depth, excitation amplitude, and are often unable to directly capture complicated phenomena such as sloshing impact with the TLD ceiling.
The goal of this study is to create a TLD model without such limitations. A smoothed particle hydrodynamics (SPH) model is developed for a TLD. SPH has seen application to TLDs in the past, however the computational requirements often make it infeasible for use outside of an academic setting. An efficient method for representing TLD damping elements is proposed in this study. This method significantly reduces the computational time by allowing for a much larger particle resolution. This enables the simulation of multiple hours of time, which has not been previously achieved using SPH.
The model is validated with experimental data. The TLD model is coupled to a structure to represent a structure-TLD system under large amplitude excitations. Modifications to the SPH solid boundary conditions for long-duration simulations are investigated to mitigate the loss of fluid particles. The influence of limiting TLD freeboard on structure-TLD system response is investigated. The model is used to simulate the response of a series-type pendulum tuned mass damper (TMD)-TLD system considering both horizontal and vertical excitation. The model is demonstrated to capture the response of TLDs across a range of complex scenarios.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Between Romantic and Pragmatic Expressivism: Charles Taylor and Jeffrey Stout on the Expressive Value of Religion

contributor:
Kroeker, P. Travis
Religious Studies

abstract:
This thesis compares the writings of Charles Taylor and Jeffrey Stout on expressivism and religion. Taylor and Stout both formulate expressivist theories in order to defend the expressive value of religion in secular modernity. Taylor appeals to a Romantic form of expressivism that highlights the importance of poetic language for articulating religious faith, while Stout argues for a pragmatic expressivism which focuses on the role of “expressive rationality” in religious language. Stout follows Robert Brandom in theorizing the rational aspects of language described by pragmatic expressivism, and applies Brandom’s philosophical project to an analysis of religious and ethical discourse. Taylor criticizes Brandom’s rationalist theory of language for its neglect of the “disclosive” dimension of language. From Taylor’s Romantic-inspired perspective, language works to theologically and ontologically “disclose” the world to human beings, which he argues is best seen through the exemplary poetic expression of post-Romantic authors such as Paul Celan and Gerard Manley Hopkins.
	The conflict between Romantic and pragmatic expressivism visible in the Taylor/Brandom debate is expanded to consider the division between Taylor’s and Stout’s approaches to the topic of religious expression. The disagreement between their expressivisms is particularly salient in their diverging approaches to metaphysics and theology. Taylor’s Romantic expressivism leaves room for both immanent and transcendent interpretations of the world, especially per the “ontological indeterminacy” of post-Romantic poetry. Stout, on the other hand, critiques metaphysics and theology for positing a non-human world of transcendence, arguing that religious expression should adapt itself to the nonmetaphysical perspective of modern secularized discourse. His criticism of Taylor’s Catholicism is considered in this respect, and rejected for its attempt to interpret Taylor as supplying a dogmatic metaphysics, whereas Taylor’s Romantic expressivism is concerned with exploring and not asserting what metaphysical or theological realities exist. Romantic expressivism is also considered in a positive light for avoiding the anthropocentrism that pragmatism is committed to.
	Finally, Taylor’s and Stout’s work on religious expression is considered in relation to their shared criticism of John Rawls’s “idea of public reason” which seeks to limit the public expression of religious ideas. Stout’s pragmatic expressivism gives him the resources to provide a more fulsome response to Rawls than that given by Taylor. Although Taylor is also concerned about Rawls’s political theory, he is ultimately more ambivalent about Rawls than Stout is. Following Brandom’s notion of “expressive freedom,” Stout crafts an appealing alternative conception of public rationality that is able to incorporate the insights of religionists.

abstract: Thesis

abstract: Master of Arts (MA)


title: Reimagining Social Work from an Islamic Worldview

contributor:
Greene, Saara
Social Work

subject: Islam; Muslims; Religion; Islamic Worldview; Islamically Informed Care; Islamically Informed Framework; Social Work; Social Services; Social Work Education; Social Justice; Islamophobia; Anti-Muslim Sentiment; Worldview; Colonialism; Decolonial Thought; Participatory Research

abstract:
With Islamophobia on the rise in Canada, it may reasonably be expected that social work,
a seemingly care-oriented profession, would have effective support readily available for
the Muslim community. However, rather than the Muslim community experiencing social
services as a place where such support can be accessed, their interactions with these
services demonstrate the ways that Islamophobia seeps into social work settings amidst
discriminatory assumptions about Muslims and a lack of religiously informed care. In
response, informed by an Islamic worldview and drawing upon decolonial thought and
community-based participatory research principles, this study aims to centre Islamic ways
of knowing, being, and doing in considering how mainstream social services and social
work practice can most effectively support the Muslim community. Emerging from
interviews with five Muslim community leaders and scholars were four key themes: the
role of Islam in the lives and well-being of Muslims; anti-Muslim sentiment and the
devaluing of Islamic identity in mainstream social work education and practice; the need
for Islamically informed care; and reimagining social work from an Islamic worldview.
The findings reveal significant challenges for the Muslim community in accessing and
receiving effective support from mainstream social services, while also underscoring
important considerations for enhanced social work practice with Muslims. Implications and
recommendations for the social work profession, social work education, and the Muslim
community are discussed, alongside suggestions for future research and action, with an
emphasis on the importance of contributions from Islam and Muslims to elicit meaningful
change.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: How much Sampling Area is Enough?: The Development of a Statistically Justified Method for Sampling Filtered Microplastics in Drinking Water

subject:
Microplastics
Drinking Water

abstract: A thesis submitted to the School of Interdisciplinary Science in partial fulfilment of the requirements for the degree of Bachelor of Science.

abstract: As awareness intensifies regarding the presence of microplastics (MPs) throughout the environment, there is a growing concern that MPs in drinking water may contribute to a toxic response in consumers. With the increasingly large volumes (> 100L) being sampled to improve accuracy, yielding potentially hundreds of MPs that must be counted, coupled with the large amount of time it requires to process MP samples, there is a need to know the minimum subsample required to accurately represent the actual MP population. In order to develop a statistically justified framework for sampling, drinking water was filtered via “in-lab” and “in-line” methods. Fifteen 10 μm filters 47 mm in diameter were examined with 70 0.7 mm² grid cells, where each cell’s total MPs were counted using an optical microscope. Suspected MPs were examined in areas ranging within zero to 100% of the filter using three strategies: i) random discontiguous, ii) one random contiguous area, and iii) two random contiguous areas equidistant from the centre. Significant clustering was observed in all but two of the fifteen filters. Subsample estimates of total suspected MPs were compared with the actual MP population via consistency values. A minimum suitable sampling area was determined to exist when a specified subsample area and every sampling interval above it had a 95% confidence interval of each filter’s upper and lower confidence intervals of consistency that fell within a suitable percentage from the true value. Results of this study suggest that out of all the sampling methods tested, discontiguous sampling is optimal. Randomly sampling one quarter of the filter results in an accuracy within ± 15%, nineteen times out of twenty. Overall, it is recommended that this method be employed for future research in order to statistically justify the sampling area required for MPs in drinking water.


title: Single image dehazing for real colored-haze images

contributor:
Chen, Jun
Electrical and Computer Engineering

abstract:
Since the problem of image dehazing is of great significance and challenging, it has
attracted many researchers for a long time. Many excellent dehazing algorithms have
emerged one after another. However, few works focus on dehazing tasks with colour
deviations. Existing methods do not perform as well as expected on real image dehazing,
especially on images with colour deviations. The proposed method mainly focuses on
this task and achieves competitive performance. In this paper, a two-step network is
proposed, which consists of the Colour Balance Module and the Dehazing Module. Hazy
images are first fed into the Colour Balance Module to generate colour corrected hazy
images, which are then sent to the pre-trained dehazing net to get the real colour corrected
haze-free results. A coloured haze image database is also constructed. Experiments and
comparisons are implemented to show the effectiveness of the proposed method, not
only on real coloured-haze images but also on other dehazing tasks.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Drought Tolerance Compared Between Two Eutrema salsugineum Ecotypes and Their Recombinant Inbred Lines

contributor:
Weretilnyk, Elizabeth
Biology

subject:
water deficits
Eutrema salsugineum
recombinant inbred lines

abstract:
Despite drought accounting for over 80% of agricultural losses, little progress has
been made towards improving drought tolerance in crops. My approach to identifying
traits underlying drought tolerance involved a comparison between two accessions of
the crucifer, Eutrema salsugineum, that display differential tolerance to water deficits.
The accessions, originating from the semi-arid Yukon, Canada, and a monsoonal region
of Shandong, China, were subjected to a two-step, water deficit and recovery
protocol to identify physiological characteristics that discern their drought-responsive
behaviour. Traits that discriminate between the ecotypes were used to screen recombinant
inbred lines (RILs) that were generated by crossing Yukon and Shandong
parent plants. Selected physiological measurements were: anthocyanin accumulation,
cut rosette water loss (CRWL), solute potential, relative water content (RWC), static
leaf water content (SLWC), specific leaf area (SLA), and OJIP fluorescence emission.
Of the measurements taken, CRWL measurements and anthocyanin content
distinguished the Yukon ecotype from the Shandong ecotype during the first drought
exposure whereas SLA and fluorescence responses differentiated these accessions better
after plants that experienced the first drought were rewatered and recovering or
undergoing a second drought treatment. Sixty-eight RILs were screened using SLA
and OJIP fluorescence emission. SLA and OJIP measurements varied among the
recombinant inbred lines (RILs) with many lines showing responses to water deficit
intermediate to those of the parental lines. Evidence of heritability in SLA and/or
OJIP responses to water deficits would make them useful phenotypic markers for
identifying quantitative trait loci (QTLs) associated with drought tolerance in future
work.

abstract: Thesis

abstract: Master of Science (MSc)


title: Impacts of Coarctation Coexisting with Other Cardiovascular Diseases on Hemodynamics Using Patient Specific Lumped Parameter and Lattice Boltzmann Modeling

contributor:
Keshavarz-Motamed, Zahra
Mechanical Engineering

subject: Coarctation of the aorta

abstract:
Effective diagnosis of COA hinges on quantifications of the global hemodynamics (heart
function metrics and workload), and the local hemodynamics (3-dimensional flow
dynamics in COA). In this study, we developed an image-based framework that can
quantify local and global hemodynamics for COA diagnosis. The proposed framework
uses lattice Boltzmann method and lumped-parameter modeling that only needs routine
non-invasive clinical patient data. The computational framework was validated against
clinical cardiac catheterization data and Doppler echocardiographic measurements.
One of the complicating factors of COA is its common association with mixed valvular
diseases (MVD), which include varying combinations of aortic and mitral valve
pathologies. Treatment strategies for these patients are quite unclear and differ from
patient to patient. In order to evaluate risk factors and create guidelines for intervention
aimed at minimizing the progression of cardiovascular disease, the impact of COA and
MVD on aortic fluid dynamics in patients with COA and MVD was investigated in this
thesis. Our results show that interaction of MVD with COA fluid dynamics may amplify
adverse hemodynamic effects especially downstream of COA and may contribute to
speed up the progression of the disease. The results suggest that some more aggressive
surgical approaches may be required as regularly chosen current surgical techniques may
not be optimal for patients with both COA and MVD.
The appropriate surgical technique for COA repair often remains unclear for adult
patients. Extra-anatomical bypass grafting has been recommended in some of the COA
cases. To effectively evaluate risk status and create guidelines for intervention, precise
quantification of aortic fluid dynamics and hemodynamics is required. We used a patient-specific numerical framework to investigate the impact of bypass grafts on aortic fluid
dynamics in patients with COA. This study can partially explain the complications
associated in patients with COA who underwent bypass grafting.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract:
Coarctation of the aorta is a congenital narrowing of the proximal descending aorta which
coexists with other cardiovascular diseases. Although accurate and early
diagnosis of coarctation hinges on blood flow quantification, proper diagnostic methods
for coarctation still lack because fluid-dynamics methods that can be used for accurate
flow quantification are not well developed yet. We developed an image-based patient-specific computational framework that can quantify hemodynamics in patients with
coarctation. Moreover, we investigated the impact of coarctation coexisting with other
diseases and its interventions on hemodynamics to answer clinical questions.


title: A Deep Recurrent Neural Network-Based Energy Management Strategy for Hybrid Electric Vehicles

contributor:
Emadi, Ali
Mechanical Engineering

subject:
hybrid electric vehicle
energy management strategy
recurrent neural network
long short-term memory network

abstract:
The automotive industry is inevitably experiencing a paradigm shift from fossil fuels to electric powertrain with significant technological breakthroughs in vehicle electrification. Emerging hybrid electric vehicles were one of the first steps towards cleaner and greener vehicles with a higher fuel economy and lower emission levels. The energy management strategy in hybrid electric vehicles determines the power flow pattern and significantly affects vehicle performance.

Therefore, in this thesis, a learning-based strategy is proposed to address the energy management problem of a hybrid electric vehicle in various driving conditions. The idea of a deep recurrent neural network-based energy management strategy is proposed, developed, and evaluated. Initially, a hybrid electric vehicle model with a rule-based supervisory controller is constructed for this case study to obtain training data for the deep recurrent neural network and to evaluate the performance of the proposed energy management strategy.

Secondly, due to its capabilities to remember historical data, a long short-term memory recurrent neural network is designed and trained to estimate the powertrain control variables from vehicle parameters. Extensive simulations are conducted to improve the model accuracy and ensure its generalization capability. Also, several hyper-parameters and structures are specifically tuned and debugged for this purpose.

The novel proposed energy management strategy takes sequential data as input to capture the characteristics of both driver and controller behaviors and improve the estimation/prediction accuracy. The energy management controller is defined as a time-series problem, and a network predictor module is implemented in the system-level controller of the hybrid electric vehicle model. According to the simulation results, the proposed strategy and prediction model demonstrated lower fuel consumption and higher accuracy compared to other learning-based energy management strategies.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Experimental evaluation of thermal response tests performed on borehole strings

contributor:
Cotton, James
Lightstone, Marilyn
Mechanical Engineering

subject:
borehole heat exchanger
thermal response test
thermal conductivity
infinite line source model

abstract:
This thesis investigates the validity of the standard thermal response test (TRT) results when
performed on a series of boreholes (string). The typical TRT consists of subjecting a single
borehole to a constant heat injection rate to obtain the temperature response in the ground which can then be used to determine the ground thermal conductivity. When completed on a single borehole, the results may be analyzed with the line source theory, since the assumption of a single line heat source is valid. For multiple boreholes, the assumption of a single line source becomes invalid if the spacing between the boreholes is small enough for borehole thermal interaction to occur. Moreover, for boreholes that are charged in series, heat transfer from the horizontal pipes that connect the vertical boreholes may also influence the ground thermal response. This thesis takes an in-depth look at the different factors that affect the results of TRTs performed on borehole strings. Different analysis methods are implemented to determine areas of improvement for determining the thermal conductivity of the soil surrounding the borehole string.
For the analysis, the infinite line source (ILS) model and a model developed using TRNSYS
18 were used to determine the effective thermal conductivity. The results show that TRNSYS is unable to accurately model a TRT performed on a borehole string. The horizontal pipe model within TRNSYS proved to have significant fundamental issues, as the effective thermal
conductivity is greatly underestimated with values of 1.2±0.1W/mK and the results of increasing the horizontal length both increased and decreased the effective thermal conductivities. The results from the ILS demonstrate that an effective thermal conductivity of 1.7±0.2W/mK is an appropriate estimate of the soil at the BTES field tested, as the borehole string with the furthest spacing between boreholes gave an effective thermal conductivity of 1.7W/mK.
Performing multiple thermal response tests within the same BTES field also provided
evidence of the need to implement multiple TRTs as common practise. The testing presented
shows that the effective thermal conductivity can vary within ±0.2W/mK within the same
relative location. With better knowledge of the thermal properties within the BTES field location comes the opportunity for improved planning of operation and control of thermal distribution
within the field. This would be especially beneficial when dealing with seasonal BTES fields

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: When the stage is shaken, and the lights go dark: Discovering how performance and social work can continue to share the spotlight together!

contributor:
Schormans, Ann Fudge
Social Work

subject:
community-based performance
COVID-19
performance groups
technological accessibility
theatre for justice
ethnographic screenplay
Online Community
qualitative interviews

abstract: Since March 2020, community-based performance social groups have shifted drastically. With COVID-19, quarantining and social distance protocols, the ongoing pandemic has altered in-person social work and the way communities interact. The information shared in this thesis is drawn from 4 semi-structured qualitative interviews. The data showcases folks who are community leaders, teachers and social workers who use performance techniques with their clients. My study asked the Participants about their history using theatre arts within their practice and investigated how COVID-19 impacted their endeavours. The data collected implies that community work using theatre has an ongoing potential to support social change efforts toward rebuilding and sustaining connection. Yet, the data also discovered a growing divide that is further affecting marginalized folks who can not access community within a digital world. Inspired by the works of Lisbeth Berbary (2011) and Jonathan Gross (2021) this thesis artistically re-imagines the collected data as a social performance amongst the Participants involved. With permission from the Participants, an ethnographic screenplay using a creative analytical approach (Berbary, 2011), transformed the semi-structured qualitative interview findings to highlight key discoveries. These key discoveries outline a nuanced understanding of how performance for social change has been transformed and the tensions that arose, particularly the growing social divide for access (the divide between those who can access online community performance groups and those who lose out from a lack of technological accessibility). Analyzing these conflicting advantages and disadvantages can help build toward an inclusive and equitable approach for theatre as a vehicle for social justice.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: Metrics for Evaluating System Level Change in Adolescent and Young Adult (AYA) Cancer Care in Canada

title: METRICS FOR AYA CANCER CARE IN CANADA

contributor:
Costa, Andrew
Health Research Methodology

subject:
Cancer
System Performance
Adolescent and Young Adult
Indicator
Oncofertility
CDS-AYA
Distress Screening
PROMs

abstract:
Adolescents and young adults (AYAs, 15-39 years of age) with cancer face
unique challenges. Efforts have been made to improve both care and outcomes for this
population. Metrics to evaluate AYA cancer care efforts help to ensure that objectives and
outcomes are being met. This thesis comprises 7 papers which explore system
performance metrics for cancer care and control in AYAs. A scoping review introduces
the topic and addresses the current state of indicator metrics for the AYA cancer
population. The second paper extends this work and develops a consensus-based list of
relevant indicators. The subsequent papers focus on further development of two of the
identified indicators for implementation in Canada (identification of patient reported
outcome measures (PROMS) for assessing distress; a referral indicator for oncofertility
care).
This thesis describes 14 indicators in 5 care areas. Two identified indicators were
further developed to aid in implementation (“Proportion of AYA patients screened for
distress with standardized AYA specific tools” and “Proportion of AYA patients who had
fertility preservation discussion before treatment”). Criteria from the National Quality
Forum (NQF) were used to assess commonly used PROMs for distress. It was found that
although all PROMs had acceptable psychometric properties, only the “Impact of Cancer”
scale of the CDS-AYA had strong content validity for AYA with cancer. For
Oncofertility, the indicator “Proportion of cases attending a fertility consult visit ≤ 30
days from diagnosis of cancer” was recommended for use. Finally, factors associated
with attending such a fertility consult were identified. Important factors for both men and
women included: age at diagnosis, risk to fertility, year of diagnosis, treatment with
radiation or chemotherapy, region of care, income and residential instability. The
information presented in this thesis can be applied to national system performance
initiatives to identify and implement metrics to monitor and evaluate cancer care in AYA.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract:
A person 15 to 39 years old with cancer will face many challenges. This is a time of life
with many changes such as continuing schooling, getting married, starting a career, or
starting a family. To make sure that young people with cancer are getting the best care,
and that they have the best chance to achieve their goals and contribute to society, we
need to measure what is important to this group. These measures can be used to compare
hospitals, or changes over time to help make care better. This paper looks at what we
already measure in this group, and what patients, researchers and healthcare workers
think also should be measured to help provide the best care for these patients. Measures
discussed in this paper could be used in programs to monitor the quality of care given to
young people with cancer.


title: Laser Powder Bed Fusion of Titanium Matrix Composites

contributor:
Elbestawi, Mohamed
Mechanical Engineering

abstract:
Laser powder bed fusion (L-PBF) is an additive manufacturing (AM) process in which an object is manufactured in a layer-by-layer manner from a batch of loose powder using a mobile laser beam as the heat source. Due to the layer-wise nature of the L-PBF process, it is capable of producing objects with complex shapes and unique geometries in bulk, porous, or cellular forms with potential applications in various industries, including aerospace, biomedical, and automotive, among others. The AM technology has recently attracted a great deal of attention in fabricating metal matrix composite (MMC) components with improved mechanical and functional properties than the non-reinforced metallic counterparts. However, full implementation of this promising technology in manufacturing high-quality MMCs is rather challenging in many aspects, such as preparing the starting material, obtaining defect-free parts, and finding suitable post-processing treatments.
This research deals with the fabrication of high-performance titanium matrix composites (TMCs) by L-PBF processing of the B4C/Ti-6Al-4V(Ti64) composite powders. Results revealed that almost fully dense TMC samples could be achieved by optimizing the process variables. To tailor the mechanical properties of the fabricated TMCs, various heat treatment cycles were employed for both TMC and monolithic Ti64 parts. The microstructures of the as-built and heat-treated TMC and Ti64 samples were thoroughly examined and correlated to the microhardness, nanohardness, wear, scratch, compression, and short-term creep properties. In addition, the strengthening mechanisms were investigated, and each mechanism's contribution to the compressive yield strengths was identified. Results revealed that the optimum heat treatment cycle for the fabricated TMC samples differs from that of the Ti64 alloy.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Examining the Substitution Effect of Assisted Living Services in Retirement Homes in Ontario, Canada

contributor:
Costa, Andrew
Health Policy

abstract: Retirement homes provide assisted living services in a residential setting to support independent living. Retirement homes predominately operate on a private, for-profit business model, and these homes are privately financed through out-of-pocket payments by residents and/or their caregivers. This thesis examines whether retirement homes are a substitute congregate care setting to long-term care in Ontario, Canada. The first study created the first population-level cohort of residents of retirement homes with health system administrative data in 2018 and compared the health service rates of residents of retirement homes relative to other older adult populations (i.e., residents of long-term care homes, home care recipients who lived in the community, and community-dwelling older adults). This study found that residents of retirement homes were a unique older adult population with the highest relative rates of hospital-based care. The second study examined the facility-level characteristics of retirement homes that provided a dementia care program in 2018. This study found that these retirement homes offered an array of care services and were fundamentally different from those that did not. The third study investigated whether residents of retirement homes who were newly diagnosed with dementia and resided in a retirement home with a dementia care program had a lower rate of transition to a long-term care home from 2014 to 2019. This study found that residents of retirement homes who had access to a dementia care program in their retirement home had a significantly lower rate of transition to a long-term care home. The findings from these three studies suggest retirement homes may be a substitute congregate care home for a long-term care home in Ontario, Canada. These findings inform health system planning, national dementia care strategies, and policies that address housing, health, and social care needs of older adults.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: This thesis examined whether retirement homes are a substitute for long-term care in Ontario, Canada. The first study created the first population-level cohort of residents of retirement homes and compared their health service use to other older adult populations. Residents of retirement homes had the highest rates of hospital-based care compared to the other older adult populations. The second study investigated the characteristics of retirement homes that provided a dementia care program. The homes that provided a dementia care program offered an array of care services. The third study investigated whether residents of retirement homes who lived with dementia and resided in a retirement home with a dementia care program transitioned more slowly to a long-term care home. Residents of retirement homes who had access to a dementia care program transitioned much slower to a long-term care home. Retirement homes may be a substitute to long-term care.


title: Preparation and application of conductive molybdenum disulfide

contributor:
Kruse, Peter
Chemistry and Chemical Biology

subject: conductive MoS2, sensor, surface chemistry

abstract:
For applications of MoS2 in batteries, supercapacitors, electrocatalysts, solar cells and water quality sensors, a substantially increased conductivity is required in order to achieve reasonable currents. Popularly, the metallic 1T-MoS2 phase is used, which can be prepared via a lithium intercalation process, requiring inert atmosphere processing and safety procedures.
In this thesis, I demonstrate a safer and more efficient process to yield conductive MoS2 (c-MoS2). This simple and effective way to prepare few layer c-MoS2 utilizes ambient conditions and 0.06 vol% aqueous hydrogen peroxide. Part of the research effort has been to enhance the conductivity of MoS2 using the idea of green solvents (like pure water). The bulk conductivities of both peroxide and water exfoliated MoS2 are up to seven orders of magnitude higher than that of the semiconducting 2H-MoS2 phase. The samples were characterized with Hall measurements, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Trace amounts of hydrogen molybdenum bronze (HxMoO3-y) and sub stoichiometric MoO3-y were shown to help tune the conductivity of the nanometer-scale thin films without impacting the sulfur-to-molybdenum ratio. c-MoS2 was further functionalized with thiols to determine the number of residual reactive sites. I also studied the mechanism of surface functionalization of MoS2 with diazonium molecules (both direct and in-situ approach) to understand the surface properties of our material and tune the chemical and mechanical properties of conductive MoS2.

An important goal of my work is to control the conductivity of the MoS2 thin films in safe and facile ways that enable their application in low-cost chemiresistive sensors for liquid environments. I fabricated chemiresistive sensors with centimeter channel lengths while maintaining low measurement voltages for pH sensing. I further measured the catalytic activity of c-MoS2 films in 0.5 M H2SO4 electrolyte solution using linear sweep voltammetry (LSV) which showed a lower Tafel value at 10 mA/cm2 current density. The lower Tafel value demonstrated that c-MoS2 has potential to use as catalyst for hydrogen evolution reaction. My study furthers the understanding of conductive forms of MoS2 and opens up a new pathway for next generation electronic and energy conversion devices.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Te…O Chalcogen Bonding in Supramolecular Chemistry

title: Te…O CHALCOGEN BONDING

contributor:
Vargas-Baca, Ignacio
Chemistry and Chemical Biology

abstract: Noncovalent interactions have attracted significant attention in the recent decades, both seeking a fundamental understanding and pursuing a wide range of applications. One particular case that has been studied in great detail is halogen bonding (XBs). The use of chalcogen bonding (ChBs) is only beginning to thrive but already has made a mark in the chemical community. In this thesis, we intended to augment the study of ChBs by examining 1,2-chalcogenazole 2-oxides. These N-oxides of C3NCh (Ch = Se, Te) heterocycles spontaneously assemble supramolecular structures through reversible Te…O ChB interactions. In solution, their macrocyclic tetramers and hexamers exist in equilibrium. These rings as well as supramolecular polymers (infinite chains in crystalline phase) have been authenticated by single-crystal X-ray diffraction. Despite the reversibility of the Te…O link, the macrocycles display properties typical of covalent macrocycles, including ability to coordinate metal ions, host small molecules, and form adducts with fullerenes. The compounds are stable to tellurium halogenation and unreactive to Lewis bases. However, they are readily cleaved by Brønsted and Lewis acids. Transformation of the structure of iso-tellurazole N-oxides by formal insertion of an aromatic bridge between the nitrogen and oxygen atoms led to a new family of supramolecular building blocks. A disubstituted benzene bridge yielded three isomers, all of which display signs of aggregation in solution and crystallize in either polymeric or macrocyclic aggregates. Among the latter, the ortho compound assembled a calixarene-like trimer while the para derivative built a macrocyclic tetramer akin to a molecular square.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Supramolecular chemistry is a rapidly growing field of research that uses non-covalent interactions to spontaneously build well-organized structures. Among such interactions, hydrogen bonds are the most investigated and highly utilized in chemical and biological systems such as in DNA self-assembly, protein folding, cellulose, synthetic polymers and more. In recent years, much attention has been given to other non-covalent interactions, in particular bonding interactions that occur between electron-rich centres with electron-poor covalently bonded atoms of elements in groups 14 to 17 on the periodic table. These bonding interactions are named according to the group of the electron-deficient elements such as halogen bonds (XBs, group 17), chalcogen bonds (ChBs, group 16), “tetrel bonds” (group 14) and “pnictogen bonds” (group 15), as alternatives to hydrogen bonding. The purpose of this thesis is to augment our knowledge of ChBs by investigating the supramolecular chemistry of iso-chalcogenazole N-oxides and related compounds. Such molecules spontaneously assemble robust supramolecular structures, like infinite chains (polymers), and macrocyclic tetramers hexamers through Te…O ChB interactions that are strong and yet reversible. The macrocyclic aggregates coordinate to transition metal ions, form adducts with fullerene and host small molecules. The unusual stability of these tellurium-containing supramolecular building blocks, in addition to their strong ChBs, facilitated these investigations. The solubility of these compounds was improved by installing non-polar bulky groups. The macrocyclic cavity can be enlarged by replacing the oxygen atom with phenoxides groups, creating a new family of supramolecular building blocks.


title: Equivalent Linear Model Based Torque Control and Performance Improvement For Switched Reluctance Motor (SRM) Drives

contributor:
Emadi, Ali
Electrical and Computer Engineering

subject:
Switched Reluctance Motor
Torque Control
Current Control
Radial Force

abstract:
Switched reluctance machines (SRMs) are gaining increasing interest in industrial applications due to their low manufacturing cost, simple and robust structure, excellent fault-tolerant capability, and reliable operation in high-temperature operating environments. However, the inherent pulsative torque and radial force lead to the well-known torque ripples and acoustic noise issues. Although there are numerous advanced methods to address the above two issues, the high nonlinearity inevitably brings difficulties in controlling the SRMs.

Since the linear SRM voltage and toque equations are simple, it would be beneficial to explore the control algorithm by using such simple linear model. The application of the linear torque model is firstly explored. To utilize such simple model, the connections between the linear toque model and the nonlinear torque model are built through the mapping. The features of these mapping curves are studied in detail. Applying the linear torque equation to generate the reference currents in the optimization-based torque sharing function method shows a significant reduction of the time consumption in solving the bi-optimization problem.

Later, the complete equivalent linear SRM model is constructed by introducing the linear voltage equation and corresponding mapping. Since the linear model is easy to predict the behaviour of SRMs, it is beneficial to apply such model in the model predictive torque control (MPTC) methods. The application of the equivalent linear model in the finite control set (FCS) MPTC method shows a low computational burden and occupies less storage space. Besides, the improved switching table in the proposed FCS MPTC method also enhances the torque control performance in high-speed operation conditions. To further reduce the torque ripples, the continuous control set (CCS) MPTC method is developed based on the constructed equivalent linear SRM model. The impossibility in analytically solving the optimization problem in the CCS MPTC method if using the original nonlinear SRM model is innovatively addressed by using the equivalent linear SRM model and properly modifying the cost function. Extensive simulation and experimental results prove the low-ripple feature of the proposed CCS MPTC method in a wide speed range.

The high nonlinearity also makes the current control of SRM drives difficult. An intersection-method-based current controller is presented to ensure good current tracking performance for SRMs. The employed adaptive flux-linkage observer makes this current controller show robust performance when there is a deviation on the employed flux-linkage characteristics.

Finally, the key but unmeasurable radial force information for the advanced acoustic reduction method is reconstructed based on the measured flux-linkage curves and some core relationship. This core relationship, which is between the square root of the radial force and the flux-linkage, is explored in detail. Simulation results reveal that the proposed method shows good radial force estimation accuracy when there is even 50% airgap length variation.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Assessing the Suitability of the Multilevel Governance Framework of the Laurentian Great Lakes Basin to Sustain the Quantity of its Stored Groundwater Resources

contributor:
Krantzberg, Gail
Geography and Earth Sciences

subject:
Groundwater
Transboundary Water Policy

abstract:
Water use in the Laurentian Great Lakes Basin (GLB) has long been governed by a framework of binational agreements between the United States and Canada, policies and decision-making standards of multilevel governments, and court rulings. Though groundwater quantity is not comprehensively monitored and groundwater insecurity is not widely reported throughout the Basin, in the context of rising regional populations increasing groundwater demand in high-use hotspots and climate change impacts simultaneously reducing aquifer recharge, this dissertation proactively examines the multi-scale interactions between multilevel governance and groundwater resources that can reduce sub-watershed scale groundwater storage (GWS) in high use and/or drought prone locales. Grounded on sustainable aquifer yield, adaptive governance and subsidiarity theories, and considered within the social-ecological system framework, the dissertation assesses the suitability of the governance framework to sustain GWS in high-groundwater-stress local contexts and provides governance reform recommendations.
Chapter 1 provides the theoretical background and analytical framing necessary to contextualize the three original manuscripts of the dissertation that are presented in Chapters 2, 3 and 4. Chapter 2 highlights multilevel governance gaps undermining groundwater security in vulnerable situations. Chapter 3 collates reported cases of sub-watershed scale GWS vulnerabilities and conducts retrospective analysis to trace the origins of present-day groundwater governance weaknesses in the GLB. Chapter 4 is a case study of the City of Guelph that applies statistical methods to confirm the causal relationship between governance and GWS. Given the City’s unique governance approach, which has allowed it to maintain groundwater availability despite being wholly groundwater dependent and in a drought-prone region, the findings demonstrate the potential effectiveness of governance approaches featuring subsidiarity and adaptiveness in addressing groundwater insecurity in similarly vulnerable communities. Chapter 5 concludes the research, summarizing the dissertation’s core contributions and recommending further research relevant to maintaining GWS. The dissertation closes with a meta-analysis of Chapters 2, 3 and 4 collating their main findings into a conceptual whole to propose a novel framework of good governance principles to better sustain GWS in the Basin’s high-stress locales.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Water use in the Laurentian Great Lakes Basin (GLB), the world’s largest freshwater store, has historically been subject to binational agreements between the United States and Canada, multilevel government statutes in both nations and court rulings. While persistent, sub-watershed scale groundwater storage (GWS) decline is not a widely reported issue in the GLB, places where they are observed are commonly in drought-prone and/or groundwater-dependent GLB communities. With growing human demand and climate stressors, this thesis adopts a proactive stance on addressing this emerging issue. As governance lies at the heart of maintaining GWS in social-ecological systems such as the GLB, this dissertation applies multidisciplinary methods to assess governance characteristics underlying growing groundwater insecurity in high-groundwater-stress situational contexts of the Basin. Findings highlight that the top-down GWS governance approach insufficiently leverages the strengths of local institutions to prevent groundwater insecurity. Findings also show that groundwater use and conservation standards have not been sufficiently based on the unique physical-environmental sustainability requirements of aquifers to maintain GWS, as they continue to be based on relatively limited 19th-century scientific understanding of groundwater flow systems. Largely unchanged over time, contemporary governance instead generally applies the same water use and conservation standards, originally developed to sustain surface water, to govern surface water and groundwater use. These conclusions inform recommendations for sustaining GWS in vulnerable locations, considering growing populations and climate uncertainties.


title: Examining the Efficacy of Attentional Focus Instruction on Typically and Atypically Developing Young Learners Performing a Postural Control Task: A Four Experiment Research Proposal

contributor:
Lyons, Jim
Kinesiology

subject: Motor Learning

subject: Children

subject: Attention

subject: Posture/Balance

subject: Motor Development

subject: Attentional Focus

subject: Attention-Deficit Hyperactivity Disorder (ADHD)

subject: Development Coordination Disorder (DCD)

subject: Paediatric Health

abstract:
Within the last decade, the influence of focus of attention (FOA) instruction on postural control has been an increased interest among researchers (Yeh et al., 2016; McNevin et al., 2013). The general agreement when it comes to the role of FOA has been that adopting an external (EXT) FOA enhances the efficiency of motor programming by strengthening the relationship between movement planning and outcome, when compared to an internal (INT) FOA (see Wulf, 2013). However, increasing evidence suggests that the benefits from an EXT FOA can be mitigated by certain factors (e.g., age, skill level, novelty of the task and task complexity; Becker & Smith, 2013; Emanuel et al., 2008). As such, questions remain as to what form of FOA instruction is best suited for young learners, as FOA research has been criticized for being studied almost exclusively among adults (Agar et al., 2016). Research in this area is particularly sparse as it pertains to FOA in combination with postural control among this younger age group. This is particularly problematic as significant changes in postural control, stability and balance occur during one’s first decade in life (Haas, et al., 1989; Hay & Redon, 1999; Barela et al., 2003). Moreover, there exists some methodological concerns with regard to the lack of consistency of FOA instructions being used during experimentation. This directly influences where participants are guiding their attention and their interpretation of FOA cues (Davids, 2007; Petranek, et al., 2019). Further, the lack of replicability of traditional FOA studies and the increasing number of non-statistically significant findings in this research, calls into question the overall validity, both internal and external, regarding FOA instruction (Becker & Smith, 2013; Lawrence et al., 2011). Therefore, as a series of four complementary studies, the overall aim of this thesis is to further investigate these theoretical as well as procedural gaps.
The first study examines which type of FOA instruction is best suited for two groups of young learners (typically developing children between 4-6 and 7-10 years of age) performing a postural control task. Participants will be randomized into either an INT, EXT or CTRL condition, where they will perform a postural control task with different respective visual displays. A force platform will be used to assess participants’ mediolateral centre of pressure (COP) performance, and electromyography (EMG) will be used to assess muscular activation of the participants’ major ankle stabilizers. The primary goal of study one is to investigate the influence of FOA in children by following the most common and traditional of FOA instruction.
The second study serves as an extension for the first study. The aim of this study is to specifically investigate the validity and reliability of using FOA instructions, and whether or not the different attentional cues can drive their intended mental focus states. The method of this study is identical to those is Study 1 with a few major exceptions. In this case, two manipulation checks will be added to the procedure in order to assess how participants perceived, comprehended, and acted to their assigned FOA instructional condition. The first manipulation check is embedded in the structure of the trial itself: the comparison of postural control performance with and without visual information, modeled after the technique used in Yeh and colleagues (2016). The second manipulation check will be a retrospective verbal interview inspired by Perreault & French (2016).
Finally, the third and fourth studies look to expand the research question from study one and two to different populations of atypically developing young learners who are known to struggle with both attention and postural control. Individuals with ADHD and individuals with DCD have been shown to interpret attentional and postural information differently when compared to age-matched controls. Therefore, the aim of these studies is to compare the differing effects of FOA across neurodiverse populations. Specifically, study three will use a group of young learners (from 4 – 10 years of age) with ADHD and study four will use a group of young learners (from 4 – 10 years of age) with DCD. The only differences in these studies compared to study one will be the lack of an age split and the use of EMG assessment.

abstract: Thesis

abstract: Master of Science in Kinesiology


title: UNION EFFECTIVENESS AND THE COVID-19 PANDEMIC: A CASE STUDY OF ONTARIO LONG-TERM CARE UNIONS

contributor:
Mills, Suzanne
Labour Studies

subject:
collective bargaining
long-term care
labour relations
unions
care work
PSWs
personal support workers

abstract:
The COVID-19 crisis in Ontario’s long-term care (LTC) sector has brought unprecedented public attention to long-established systematic weaknesses in funding, staffing, and working conditions that have rendered both workers and residents highly vulnerable to infection. This study seeks to understand why unions have been unable to better protect long- term care workers from vulnerability to COVID-19 by exploring the effectiveness and limitations of unionization and assessing the challenges that unions have faced in safeguarding workers.
Eight union representatives amongst SEIU, CUPE, and OPSEU were selected as participants for hour-long semi-structured interviews. Interviews were thematically analyzed for challenges to union power as well as workplace attributes related to COVID protection. Twelve collective agreements were examined to assess the relative strength and weakness of clauses relating to health and safety, paid sick leave, disability benefits, wages, and job security in relation to part-time PSWs.
Collective agreements offered limited and varying degrees of protection to workers as unions faced constraints in bargaining within a largely privatized sector under the arbitration- based Hospital Labour Disputes Arbitration Act. The ubiquity of precarious, part-time PSW positions was identified as a major risk factor of COVID vulnerability. Unions also faced four challenges to their effectiveness: the structure of bargaining; challenges in member engagement; the neglect of long-term care and privatization of health-care; and labour relations with the Ford government. In addition to legislative reform concerning staffing and funding, this study suggests that unions engage in deeper forms of worker organizing to develop and exercise labour power beyond the legal confines of the strike-prohibiting HLDAA, as job action elsewhere by feminized healthcare workers has been met with public support and contributed to changes in conditions of care and work.

abstract: Thesis

abstract: Master of Arts (MA)


title: Leveraging Public Exome Sequencing Data to Find Rare Causal Variants in Type 2 Diabetes

contributor:
Paré, Guillaume
Health Sciences

subject: Rare variants, exome sequencing, type 2 diabetes, RV gene burden, UKB, DBGaP, GnomAD

abstract:
Background: Type 2 Diabetes (T2D) is growing in prevalence worldwide over the last century. T2D incidence is linked to numerous complications, increased risk of heart disease, and oncology outcomes. This highlights the importance of preventive measures for T2D, wherein genetic predisposition can serve as an early warning sign. The role of rare variants (RVs) in T2D pathogenesis has not been adequately explored due to study size limitations, therefore we hypothesized that new associations could be found using publicly available data repositories.
Methods: Significant RV gene burden for T2D risk was discovered using exome sequences obtained from the United Kingdom Biobank (UKB) (n=162,215), then tested for replication in the Korean Association Resource project (n=973), the Metabolic Syndrome in Men Study (n=969), the San Antonio Mexican American Family Studies (n=309), and a pooled meta-analysis of the latter three cohorts. RV gene burden was reassessed in secondary analyses using T2D cases from each cohort and summary level data from the Genome Aggregation Database (GnomAD) (n=125,748).
Results: UKB exome wide significant associations were found in GCK (OR=2.44, p=8.91×10-11) and PAM (OR=1.32, p=1.39×10-6), and suggestive associations (p<0.001) were found in 33 additional genes. Replication was limited in KARE, METSIM, SAMAFS and in the secondary analyses with GnomAD because of limited sample sizes and miscalibration with the external control, respectively. Follow-up analyses include exploration of RV gene burden in additional diabetes subtypes, evaluation of clinical features between RV carriers and non-carriers, comparing the ability to predict T2D with rare variant, polygenic, and phenotypic risk scores. Methodological improvements include the incorporation of robust analytic tools and increasing access to a greater diversity and number of samples.
Conclusion: Publicly available exome sequencing data has identified genes where RV burden affects T2D pathogenesis and risk. The study of rare genetic variation in diabetes is just beginning.

abstract: Thesis

abstract: Master of Science (MSc)


title: Albumin As a Platform for Radiotherapy and Antibody-Recruiting Therapy

contributor:
Valliant, John
Sadeghi, Saman
Rullo, Anthony
Chemistry and Chemical Biology

subject: radiochemistry radiotherapy antibody-recruitment immunology

abstract:
The aim of this thesis was to develop and evaluate albumin-based conjugates for their use in radiotherapy and antibody-recruiting therapy which may then be combined to enhance therapeutic efficacy of each monotherapy. The approach taken in order to achieve high tumour uptake of the conjugates and minimize doses to healthy tissues involved the intratumoural administration of therapeutic compounds; a technique which has gained popularity in recent years for the treatment of solid tumours. Despite the promise this method of administration holds, it is often limited by the fast clearance of injected compounds from the tumour. Using albumin-based conjugates allows for the exploitation of the enhanced permeation and retention (EPR) effect which aids in the retention of the compound at the site of interest for longer periods of time, thus allowing the opportunity for enhanced therapeutic efficacy.
Bovine serum albumin conjugated with DOTA chelators was first synthesized and found to possess 3.9 ± 0.4 chelates per BSA molecule. Radiolabelling of the compound with lutetium- 177 produced the desired product in radiochemical yields of 74 ±2 % with a radiochemical purity >99%. The stability of the compound was evaluated by monitoring the radiochemical purity over 7 days which was found to be >95% pure over the entirety of the testing period, indicating a stable product. The intratumoural administration of [177Lu]Lu-DOTA-BSA in a triple negative breast cancer (TNBC) tumour model revealed significant tumour retention of 52 ± 12 %ID/g and 35 ± 6 %ID/g at 24 h and 72 h post-injection, respectively, while autoradiography displayed a heterogenous dispersion of the compound throughout the tumour. A multidosing therapy study in which animals received two doses of either 4.44, 5.92, or 7.40 MBq of [177Lu]Lu-DOTA-BSA showed promise, with a strong trend observed between the administration of higher doses and a prolonged lifespan. Histological analysis of tumours excised 7 days post-treatment revealed signs
iv
of necrosis and apoptosis in tumours treated with 7.40 MBq [177Lu]Lu-DOTA-BSA. These preliminary results prove to be a promising approach for use in combination therapy and may be further optimized to enhance its efficacy as a monotherapy.
Next, the in vivo evaluation of DNP-BSA was carried out to assess using an intratumourally administered, albumin-based platform for antibody-recruiting in a triple negative breast cancer model. A preliminary antibody-recruiting study administering 35 nmol DNP-BSA three times per week unfortunately did not induce slowed tumour growth nor did it have an impact on lifespan. Treated mice were also unable to tolerate repeated doses of the antigen which indicated too high of a concentration and/or dosing frequency was used. A tolerability study was then carried out in order to determine a treatment schedule which did not lead to adverse effects. Mice treated once per week with low (9 nmol) to moderate (17 nmol) doses of DNP-BSA did not display toxic effects but unfortunately did not exhibit a therapeutic effect nor any indication that an adaptive immune response was achieved. These results suggest that further optimization is required prior to use in combination therapy and moderate doses (17 nmol) DNP should be used to investigate a treatment schedule which is able to induce antibody recruitment.

abstract: Thesis

abstract: Master of Science (MSc)


title: The effect of apparent distance on visual spatial attention in simulated driving

title: Apparent Distance and Attention in Simulated Driving

contributor:
Sekuler, Allison B.
Sun, Hong-Jin

subject:
Perception
Attention
Depth
Distance
Useful field of view
Peripheral vision
Driving

abstract:
Much about visual spatial attention has been learned from studying how observers respond
to two-dimensional stimuli. Less is known about how attention varies along the
depth axis. Most of the work on the effect of depth on spatial attention manipulated
binocular disparity defined depth, and it is less clear how monocular depth cues affect
spatial attention. This thesis investigates the effect of target distance on peripheral
detection in a virtual three-dimensional environment that simulated distance using pictorial
and motion cues. Participants followed a lead car at a constant distance actively
or passively, while travelling along a straight trajectory. The horizontal distribution of
attention was measured using a peripheral target detection task. Both car-following and
peripheral detection were tested alone under focussed attention, and simultaneously under
divided attention. Chapter 2 evaluated the effect of target distance and eccentricity
on peripheral detection. Experiment 1 found an overall near advantage that increased at
larger eccentricities. Experiment 2 examined the effect of anticipation on target detection
and found that equating anticipation across distances drastically reduced the effect
of distance in reaction time, but did not affect accuracy. Experiments 3 and 4 examined
the relative contributions of pictorial cues on the effect of target distance and found that
the background texture that surrounded the targets could explain the main effect of distance
but could not fully account for the interaction between distance and eccentricity.
Chapter 3 extended the findings of Chapter 2 and found that the effect of distance on
peripheral detection in our conditions was non-monotonic and did not depend on fixation
distance. Across chapters, dividing attention between the central car-following and
peripheral target detection tasks consistently resulted in costs for car-following, but not
for peripheral detection. This work has implications for understanding spatial attention
and design of advanced driver assistance systems.

abstract: Dissertation

abstract: Doctor of Science  (PhD)

abstract:
Our visual world is complex and dynamic, and spatial attention enables us to focus
on certain relevant locations of our world. However, much of what we know about
spatial attention has been studied in the context of a two-dimensional plane, and less
is known about how it varies in the third dimension: depth. This thesis aims to better
understand how spatial attention is affected by depth in a virtual three-dimensional
environment, particularly in a driving context. Generally, driving was simulated using
a car-following task, spatial attention was measured in a task that required detecting
targets appearing at different depths indicated by cues perceivable with one eye. The
results of this work add to the literature that suggests that spatial attention is affected
by depth and contributes to our understanding of how attention may be allocated in
space. Additionally, this thesis may have implications for the design of in-car warning
systems.


title: EXPLORING BRAIN CONNECTIVITY USING A FUNCTIONAL-STRUCTURAL IMAGING FUSION PIPELINE

contributor:
Hall, Geoffrey
Biomedical Engineering

subject:
Brain Connectivity
Diffusion Tensor Imaging
Data Fusion
Functional Magnetic Resonance Imaging

abstract: In this thesis we were interested in combining functional connectivity (from functional Magnetic Resonance Imaging) and structural connectivity (from Diffusion Tensor Imaging) with a data fusion approach. While data fusion approaches provide an abundance of information they are underutilized due to their complexity. To solve this problem, we integrated the ease of a neuroimaging toolbox, known as the Functional And Tractographic Analysis Toolbox (FATCAT) with a data fusion approach known as the anatomically weighted functional connectivity (awFC) approach - to produce a practical and more efficient pipeline. We studied the connectivity within resting-state networks of different populations using this novel pipeline. We performed separate analyses with traditional structural and functional connectivity for comparison with the awFC findings - across all three projects. In the first study we evaluated the awFC of participants with major depressive disorder compared to controls. We observed significant connectivity differences in the default mode network (DMN) and the ventral attention network (VAN). In the second study we studied the awFC of MDD remitters compared to non-remitters at baseline and week-8 (post antidepressant), and evaluated awFC in remitters longitudinally from baseline to to week-8. We found significant group differences in the DMN, VAN, and frontoparietal network (FPN) for remitters and non-remitters at week-8. We also found significant awFC longitudinally from baseline to week-8 in the dorsal attention network (DAN) and FPN. We also tested the associations between connectivity strength and cognition. In the third study we studied the awFC in children exposed to pre- and postnatal adversity compared to controls. We observed significant differences in the DMN, FPN, VAN, DAN, and limbic network (LIM). We also assessed the association between connectivity strength in middle childhood and motor and behavioural scores at age 3.  Therefore, the FATCAT-awFC pipeline, we designed was capable of identifying group differences in RSN in a practical and more efficient manner.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Data-driven Strategies for Systemic Risk Mitigation and Resilience Management of Infrastructure Projects

contributor:
El-Dakhakhni, Wael
Ezzeldin, Mohamed
Civil Engineering

subject:
Infrastructure resilience
Risk management
Project management
Construction management
Data analytics
Machine learning
Network science
Predictive solutions
Adaptive systems
Performance indicators
Systemic risk
Complex systems
Interdependence

abstract: Public infrastructure systems are crucial components of modern urban communities as they play major roles in elevating countries’ socio-economics. However, the inherent complexity and systemic interdependence of infrastructure construction/renewal projects have left sites hindered with multiple forms of performance disruptions (e.g., schedule delays, cost overruns, workplace injuries) that result in long-term consequences such as claims, disputes, and stakeholder dissatisfactions. The evolution of advanced data-driven tools (e.g., machine learning and complex network analytics) can play a pivotal role in driving improvements in the management strategies of complex projects due to such tools’ usefulness in applications related to interdependent systems. In this respect, the research presented in this dissertation is aimed at developing data-driven strategies geared towards a resilience-based approach to managing complex infrastructure projects. Such strategies can support project managers and stakeholders with data-informed decision-making to mitigate the impacts of systemic interdependence-induced risks at different levels of their projects. Specifically, the developed data-driven resilience-based strategies can empower decision-makers with the ability to: i) predict potential performance disruptions based on real-time and dynamic project conditions such that proactive response/mitigation strategies and/or contingencies can be deployed ahead of time; and ii) develop adaptive solutions against potential interdependence-induced cascade project disruptions such that rapid restoration of the most important set of performance targets can be restored. It is important to note that data-driven strategies and other analytics-based approaches are not proposed herein to replace but rather to complement the expertise and sensible judgment of project managers and the capabilities of available analysis tools. Specifically, the enriched predictive and analytical insights together with the proactive and rapid adaptation capabilities facilitated by the developed strategies can empower the new paradigm of resilience-guided management of complex dynamic infrastructure projects.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: A Qualitative Analysis of the Resettlement Experiences of Refugee Claimants in Hamilton, Ontario

contributor:
Newbold, Bruce K
Geography

subject: Refugee Claimants and Housing

abstract:
This thesis explores the relationship between restrictive screening techniques imposed by landlords and the ability of refugee claimants to access housing in a medium-sized Canadian city. While existing research has explored refugees’ experiences with resettlement, few have focused specifically on refugee claimants who arrive in their destination country with specific health needs, limited resources, and access to different services compared to other entry categories. Using qualitative research techniques, this study sought to better understand the experiences of refugee claimants as they search for housing in a medium-sized Canadian city. Through interviews with service providers, volunteers, and refugee claimants themselves, three main themes were identified.
First, we explore the relationship between a competitive housing market and the ability of landlords to be selective about who they rent to. Our findings suggest that the power imbalance between landlords, tenants and applicants is only amplified in a competitive market and allows landlords to choose applicants based on their own personal biases. Second, participants identified strict rental applications as the primary mechanism used by landlords to filter applications and identify tenants that they deemed to be “desirable”, while excluding other groups. In many cases, refugee claimants were found to be uniquely (and negatively) impacted by this practice because they often do not have the personal or financial resources available to successfully fill out these applications. Finally, participants identified two structural barriers which hindered a refugee claimants’ ability to access housing and, when combined with strict rental applications, often resulted in their exclusion from housing. This thesis is relevant to the current Canadian context, given the government’s continued commitment to resettling refugees and the increasingly competitive housing markets across Canada. Overall, this thesis adds to the existing literature regarding the resettlement experiences of refugee claimants and their ability to access housing in a medium-sized Canadian city.

abstract: Thesis

abstract: Master of Arts (MA)


title: Optimization and Characterization of Bi-detector Coincidence Beta-ray Spectrometer

contributor: Radiation Sciences (Medical Physics/Radiation Biology)

subject:
Beta spectroscopy
Coincidence operation
Monte Carlo simulation

abstract: With the recent change of the equivalent dose limit for the lens of eyes from 150 to 20 mSv/yr., averaged over 5 years, it is of great importance to investigate the beta-ray spectrum in the maintenance areas of the nuclear power plants, where workers are exposed to mixed beta-gamma fields. A beta-ray spectrometer consisting of a thin silicon detector and a plastic scintillator has been developed, which can accept only beta detection events while rejecting gamma events via coincidence. Based on the spectroscopy system that has been built, a comprehensive upgrade of software and hardware has been conducted. The data acquisition software MC2 was replaced with CoMPASS, developed by CAEN to achieve higher stability and functionality. Optimal shaping parameters and coincidence time window were determined by instruction and sample tests. The fast event signal from the plastic scintillator does not provide enough energy information. Therefore, three approaches were executed, including adding a capacitor, adding a preamplifier, and changing the digital pulse processor to solve the problem. The method of changing digitizer was accepted as the final solution to obtain the best spectrum through benchmark tests. The experimental measurements characterized the response of the beta-ray coincidence spectrometer under the mixed beta/gamma radiation field with a various count rate ratio from 0.00625 to 0.8. Experimental result shows excellent and stable performance of the detector system under a higher beta to gamma ratio. Gamma contribution of the coincidence spectrum, especially in low energy region, significantly increased when beta count rate was controlled to a minor level. Monte Carlo simulations are also carried out using the MCNP6 code to validate the measurements.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: With the recent change of the equivalent dose limit for the lens of eyes from 150 to 20 mSv/yr., averaged over 5 years, it is of great importance to investigate the beta-ray spectrum in the maintenance areas of the nuclear power plants, where workers are exposed to mixed beta-gamma fields. A beta-ray spectrometer consisting of a thin silicon detector and a plastic scintillator has been developed, which can accept only beta detection events while rejecting gamma events via coincidence. Based on the spectroscopy system that has been built, a comprehensive upgrade of software and hardware has been conducted to slow down the signal and achieve higher stability. The experimental measurements characterized the response of the beta-ray coincidence spectrometer under the mixed beta/gamma radiation field with a various count rate ratio from 0.00625 to 0.8. Experimental result shows excellent and stable performance of the detector system under a higher beta to gamma ratio. Gamma contribution of the coincidence spectrum, especially in low energy region, significantly increased when beta count rate was controlled to a minor level. Monte Carlo simulations are also carried out using the MCNP6 code to validate the measurements.


title: Data-Driven Models for Infrastructure Climate-Induced Deterioration Prediction

contributor:
El-Dakhakhni, Wael
Civil Engineering

subject: Asset Management, Bridge Condition Index, Climate Indices, Data-Driven Models, Deterioration Rate, Genetic Programming, Infrastructure, Multigene, Symbolic regression

abstract: Infrastructure deterioration has been attributed to insufficient maintenance budgets, lacking restoration strategies, deficient deterioration prediction techniques, and changing climatic conditions. Considering that the latter adds more challenges to the former, there has been a growing demand to develop and implement climate-informed infrastructure asset management strategies. However, quantifying the impact of the spatiotemporally varying climate metrics on infrastructure systems poses a serious challenge due to the associated complexities and relevant modelling uncertainties. As such, in lieu of complex physics-based simulations, the current study proposes a glass box data-driven framework for predicting infrastructure climate induced deterioration rates. The framework harnesses evolutionary computing, and specifically multigene genetic programming, to develop closed-form expressions that link infrastructure characteristics to relevant spatiotemporal climate indices and predict infrastructure deterioration rates. The framework consists of four steps: 1) data collection and preparation; 2) input integration; 3) feature selection; and 4) model development and result interpretation. To numerically demonstrate its utility, the proposed framework was applied to develop deterioration rate expressions of two different classes of concrete and steel bridges in Ontario, Canada. The developed predictive models reproduced the observed deterioration rate of both bridge classes with coefficient of determination (R2) values of 0.912 and 0.924 for the training subsets and 0.817 and 0.909 for the testing subsets of the concrete and steel bridges, respectively. Attributed to its generic nature, the framework can be applied to other infrastructure systems, with available historical deterioration data, to devise relevant effective asset management strategies and infrastructure restoration standards under future climate scenarios.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: TARGETING DNA DAMAGE AND REPAIR TO OVERCOME THERAPY MEDIATED TUMOR IMMUNE EVASION AND HETEROGENEITY IN THE CONTEXT OF ONCOLYTIC VIRUS VACCINATION

contributor: Medical Sciences (Molecular Virology and Immunology Program)

subject:
VSV
Vaccinia
DNA Damage
DNA Repair
ACT
OV
Combination Therapy
Oncolytic Virus Vaccines
Mirin
AZD7648
B16F10
Vesicular Stomatitis Virus
Melanoma
DNA Repair Inhibition

abstract: Due to the inevitable reality that most patients diagnosed with cancer will eventually relapse, modern oncology research has been forced to tackle this outcome primitively using combination therapies. Adoptive T-cell transfer with Oncolytic Virus Vaccination represents a new class of combination therapies that can facilitate the crosstalk of multiple aspects of the immune system such that they work in concert to prevent this outcome for many types of cancer. Despite this, immunosuppressive systems like those characterized in the B16F10-gp33 melanoma model pose a new problem for this approach. Typically, this model has total regression but is subsequently followed by relapse. Previous work from the Wan lab has suggested that this may be an outcome of total target gene deletion. Here we present two approaches to tackle this through the targeting of DNA repair pathways of the host cell. Our data can show that both VSV and Vaccinia infection/ propagation does lead to the generation of DNA damage but in the case of VSV this leads to incomplete cell lysis, and ultimately target gene loss via double-stranded DNA repair mechanisms. We were able to tackle the phenomenon following VSV administration by adding DNA repair inhibitors to the mix and showed that the proportion of cells that escaped after the loss of the target antigen was decreased by half when compared to the standard procedures. Additionally, this work also gave a preliminary understanding of how Vaccinia may achieve a similar outcome to this via its unique cytoplasmic replication mechanisms.

abstract: Thesis

abstract: Master of Science (MSc)


title: THE USE OF WEB-BASED VIDEOCONFERENCING FOR LIFELONG LEARNERS DURING THE CORONAVIRUS DISEASE PANDEMIC

title: WEB-BASED LIFELONG LEARNING DURING THE PANDEMIC

contributor:
Grignon, Michel
Health and Aging

subject:
pandemic
COVID-19
lifelong learning
videoconferencing
older adults
geragogy

abstract:
My thesis explores older adult lifelong learners’ experiences in transitioning their continued education participation to an online model. This research acknowledges and situates itself in the geragogy contexts of older adult learners, drawing on their experiences of the pandemic and lifelong learning, in addition to their opinions on education for older adults.
As such, a case study methodology was employed so that this case could be studied within boundaries created by the pandemic. In my study, 25 older adult learners participated in individual interviews and provided their opinions and perceptions about their experiences with the pandemic and its effect on their learning ambitions.
The COVID-19 pandemic has impacted these individuals differently based on their motivations and previous experiences with technology. Four distinct dialogue groups emerged based on the motivations that older adults have to participate in lifelong learning, which are social or instrumental, and also the opinions they have about technology, which are either positive or negative.
The four dialogues are distinct in that they each hold alternate opinions about the two issues raised (motivators and opinions on technology) but there were no major identifiers within the groups that could characteristically distinguish one from another. The results indicate that not all discourses of lifelong learners are reducible to identities or recent experiences. My findings suggest that potential refinement in program delivery based on specific user needs could improve the experiences that older adults have in the virtual classroom, and that it is crucial to the administration of lifelong learning that older adults' unique needs are addressed in a collaborative manner.

abstract: Thesis

abstract: Master of Arts (MA)

abstract: This study investigated how older adults, who pursue lifelong learning in-person, have interpreted their transition to online learning because of COVID-19 pandemic meeting restrictions. Lifelong learners have had to transition from in-person learning to virtual formats, which has encouraged new older adults to become lifelong learners, and also for some lifelong learners to drop out of the practice entirely. The key goal of the study was to describe the Transitioners, New learners, and Dropout learners' experience with lifelong learning with respect to COVID-19’s impacts on their participation. Interviews were conducted with individuals who fell into these three categories and, through their responses, distinct dialogues emerged to describe their motivation to participate in lifelong learning, and their opinions on using technology as a means to access it. Confirming the motives to participate and how technology is appreciated by lifelong learners enables us to better develop and implement lifelong learning.


title: μSR and AC Susceptibility as a probe of Frustrated Pyrochlore Magnets and Type-1 Superconductivity

contributor:
Luke, Graeme
Physics and Astronomy

subject:
Frustrated Magnetism
muSR
Superconductivity

abstract:
In this thesis, we use Muon Spin Rotation, Relaxation, and Resonance (μSR) as a probe
for three frustrated pyrochlore systems; Gd2ScNbO7 (GSNO), Nd2ScNbO7 (NSNO) and
Sm2Ti2O7 (STO), as well as the type-I superconductor BeAu. We grew all of the pyrochlore
samples at McMaster using the Optical Floating Zone method. We make use of
Direct Current (DC) and Alternating Current (AC) susceptibility, powder x-ray diffraction
and Laue x-ray diffraction to characterize our samples. We make use of AC susceptibility
measurements to explore the dynamics of the classical spin-ice Dy2Ti2O7 (DTO)
and find that the system acts as a supercooled magnetic liquid, analogous to glassforming
dielectric liquids. We find GSNO is a dense spin-glass based on our μSR and
AC susceptibility measurements. NSNO is a moment fragmentation candidate where
spin-ice, as well as all-in all-out magnetic ordering, are observed simultaneously. Our
μSR measurements on this material show a strong similarity to another moment fragmentation
candidate, Nd2Zr2O7, suggesting NSNO may be in a similar state. STO is
a closely related compound that fully orders into a magnetic state which we study using
μSR. We find subtle evidence of this magnetic transition along with persistent spin
dynamics which we suggest has a common, but as of yet unexplained, origin as other
frustrated pyrochlores measured in μSR. Finally, we use μSR to measure the temperature
dependence of the critical field in the type-I superconductor BeAu. Using an ellipsoid of
BeAu and a pressure cell, we study the magnetic properties of the sample under pressure.

abstract: Thesis

abstract: Candidate in Philosophy


title: Quantification of Respiratory Motion in Positron Emission Tomography for Precise Radiation Treatment of Lung Cancer

contributor:
Vlad, Roxana
Medical Physics

subject:
Lung Cancer
Positron Emission Tomography
Radiotherapy
Radiation Therapy

abstract:
A well-established method for treating lung cancer is curative-intent radiation therapy (RT). The most significant challenge for RT is to accurately target the lesion volume while avoiding the irradiation of surrounding healthy tissue. Currently at the Juravinski Cancer Centre (JCC), treatment plans for lung cancer patients are completed using fluorodeoxyglucose positron emission tomography (FDG-PET) and four-dimensional computed tomography (4DCT) images. There is no clear protocol, however, to compensate for respiratory motion in PET images and it is not known how lesion volumes generated from PET reflect the true volume. This project evaluated methods to optimize the use of PET images in the radiation treatment planning workflow and quantify the effects of respiratory motion. First, a 4D XCAT digital phantom was used to quantify respiratory motion and its effects on lesion displacement. A CTN physical phantom and 3D-printed irregularly shaped lesion were imaged to determine the accuracy of the PET EDGE automated segmentation algorithm (ASA). Lastly, rigid and deformable image registration techniques were used to propagate the diagnostic PET scan of the irregular lesion to the 4D planning CT. PET EDGE was used to generate target volumes which were then compared to internal target volumes (ITVs) generated from manual contouring of the 4DCT image alone.
	We found that lesion displacement due to respiratory motion can be adequately modeled using a moving platform set to oscillate 1 cm and 2 cm for normal and deep breathing, respectively. Optimal target delineation was found when diagnostic PET was propagated to the planning CT using rigid image registration for lesions that experienced 1 cm of oscillatory motion during imaging. In contrast, PET EDGE would overestimate volumes in static cases and underestimate volumes in instances of 2 cm dynamic motion meant to simulate deep breathing.

abstract: Thesis

abstract: Master of Science (MSc)


title: Low-Cost Smartphone-Operated Readout System for Point-of-Care Electrochemical and Photoelectrochemical Biosensing

contributor:
Soleymani, Leyla
Biomedical Engineering

subject:
potentiostat
point-of-care
photoelectrochemistry
electrochemistry
biosensing
readout
readout instrument
smartphone-operated
actuation
DNA detection
voltammetry
multiplex
DNAzyme
Android

abstract: Despite the increasing number of electrochemical and photoelectrochemical biosensors reported in the research literature, few have achieved success outside of a laboratory setting. This can partly be attributed to accessibility issues with commercially available readout instruments. Consequently, low-cost and portable readout instruments have been developed by researchers, but these devices fail to address other key compatibility and accessibility challenges. Much like the commercial systems, these devices are not natively compatible with multiplexed signal assays consisting of two or more working electrodes, cannot control optical excitation sources for photoelectrochemical biosensing, nor can they interface with auxiliary instruments such as heaters and electromagnets. To this end, we have developed a low-cost smartphone-operated electrochemical and photoelectrochemical readout system for point-of-care biosensing. Our readout system can perform standard voltammetric techniques and is capable of synchronously controlling an optical excitation source to support photoelectrochemical biosensing. This device is compatible with standard three-electrode assays as well as dual signal assays with two working electrodes. We have also created a portable sample heater that can be controlled by this readout system to facilitate on-site sample heating and have also integrated a portable electromagnet to perform away-from-lab magnetic manipulation.

abstract: Thesis

abstract: Master of Applied Science (MASc)

abstract: Early and prompt detection of disease biomarkers is crucial in order to develop effective disease management strategies. Unfortunately, many gold-standard diagnostic techniques for infectious diseases, cancers, heart diseases, among other conditions prove to be time-consuming, costly, and reliant on trained professionals in a laboratory setting. Electrochemical and photoelectrochemical detection are two sensing modalities that show promising potential for point-of-care applications, as they are easily miniaturized, inexpensive, and can be used to detect both the presence of and the amount of analyte present. However, up until now, these sensing modalities have mostly been confined to research settings. To expedite the commercialization of such sensors and to facilitate their translation to point-of-care diagnostics, we have developed a low-cost smartphone-operated electrochemical and photoelectrochemical readout system. Through the integration of peripheral instruments including a sample heater, electromagnet, and optical excitation source, this system is compatible with a number of different biosensors.


title: Synchronized Activity Rhythms and Collective Motion in Ant Colonies

contributor:
Faure, Paul
Psychology

subject:
Ants
Collective behaviour

abstract: The ability to synchronize both the movements and activity rhythms of many interacting individuals is a major component of the repertoire of collective behaviour in social species. Among the many social animals on Earth, ants have some of the most spectacular forms of synchronized behaviour because of their eusociality. One example of this impressive behavioral synchronization in ants is the so-called short-term activity cycle, where the workers inside a nest will move together in rhythmic pulses of activity that are separated by moments of collective rest and inactivity. There are many aspects of short-term activity cycles that are poorly understood. The first chapter of this thesis makes the case for why ants are a useful taxonomic group for studying social synchronization and introduces the phenomenon of ant short-term activity cycles. In chapter 2, I study intraspecific variation in short-term activity cycles and show that colonies’ queens, number of brood items, and number of workers all influence aspects of colony-level activity oscillations. In chapter 3, I show that colonies are capable of synchronizing despite noise in the behaviour of individual ants, and that colonies can modulate between multiple collective rhythms. In the same chapter, I also devised a model to study the role of noise more generally in excitable systems that have properties similar to those in ant colonies. Chapter 4 examined the effect of 24-hour light cycles on circadian activity, and I found that colonies kept in conditions with constant light or darkness had weaker circadian rhythms than colonies in an alternating light/dark regime. However, colonies’ short-term activity cycles were not affected by the external light regime. In chapter 5, I provide evidence that having synchronized rhythms of rest and activity provides a functional benefit for colonies: workers can, on average, more fully inspect the inside of the nest when activity is synchronized because inactive ants aggregate into piles that active ants have difficulty penetrating. In chapter 6, I recount a history of the research into synchronized and rhythmic activity patterns inside ant nests and consolidate the new results from the previous chapters with the existing literature to create an up-to-date review of what we currently know about short-term activity cycles. The work compiled here thereby sheds new light on an enigmatic form of synchronized behaviour in ants, one of the most ecologically important groups of animals on the planet.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Modelling the fill-and-spill dynamics and wildfire impacts on the hydrological connectivity of ephemeral wetlands in a rock barrens landscape

contributor:
Waddington, James Michael
Earth and Environmental Sciences

subject:
hydrology
peatlands
rock barrens
connectivity
modelling
wildfire
disturbance
fill-and-spill

abstract:
Ontario’s rock barrens landscape consists of exposed bedrock ridges which host a mosaic of thin lichen- and moss- covered soil patches, forested valleys, beaver ponds, and depressional wetlands. Peat-filled ephemeral wetlands within bedrock depressions act as gatekeepers to hydrological connectivity between their small headwater catchments and the rest of the landscape downstream through strong fill-and-spill dynamics. We developed a water balance model, RHO, with inputs of precipitation and potential evapotranspiration (PET) to better understand the factors impacting water table (WT) and storage dynamics and in turn the hydrological connectivity of ephemeral wetlands. Field surveys were conducted at six wetlands to obtain and determine the variability in measurable site characteristics, in particular the wetland depression morphometry, to parameterize RHO. Three sites were used in a calibration and validation procedure where modelled WTs were compared to measured WT data from the snow-free seasons for each site to determine the best parameter values. We show that RHO is capable of predicting WT dynamics with inputs of precipitation and PET, when parameterized for specific sites.
Wildfire disturbance is known to increase the run-off from hillslopes and remove surface organic soils through combustion. To predict the impacts of wildfire disturbance on ephemeral wetland hydrological connectivity, a generic model wetland depression was parameterized in RHO and used to predict the changes in hydrological connectivity under various wildfire scenarios and test the sensitivity of modelled connectedness to impacted parameters. Modelled results show that connectivity increases under all scenarios tested, and that changes to connectivity are primarily due to increases in run-in.
Water balance models, like RHO, can be used to better understand the hydrological connectivity of wetlands in a rock barrens landscape. These models are useful in predicting impacts on the hydrological connectivity, and hydrological ecosystem services, from disturbances such as wildfire and can inform future field research experimental designs.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Rock barrens landscapes provide several important ecosystem services, which are influenced by hydrological flow paths and water storage on the landscape. Central to these hydrological dynamics is the storage and discharge of water in small wetlands which form in bedrock depressions. Here we develop a simple hydrological model to simulate the water storage and discharge of rock barrens wetlands. We then use this model to explore how wildfire disturbance is likely to change the supply of water to the rest of the landscape by simulating several different scenarios and testing which changes in the model have the largest impact on the water supply. We show that wetlands discharge more water after wildfire disturbance, mainly because of increases in run-off from areas upstream of the impacted wetlands. This modelling approach helps us better understand how wildfire is likely to impact the ecosystem services of a rock barrens landscapes.


title: Assessing the overwintering habitat ecohydrology of an at-risk snake after wildfire

subject: massasauga ecohydrology wildfire overwintering peatland

abstract: Peatland ecosystems in the eastern Georgian Bay, Ontario, region often provide overwintering habitat for the eastern massasauga rattlesnake (Sistrurus c. catenatus), a species considered at-risk across its range. Suitable overwintering habitat requires a resilience zone with peat temperatures above 0°C and a water table position sufficient to provide moisture without risk of flooding and these ecohydrological conditions commonly occur in raised peatland microforms (hummocks). Due to a changing climate, these peatlands are at risk of increased wildfire frequency and burn severity which may threaten overwintering habitat availability and suitability. In 2018, a wildfire burned over 11,000 ha of the eastern Georgian Bay landscape which serves as critical habitat for the massasauga. We monitored water table position, snow depth, rainfall, and peat thermal dynamics in hummocks in three burned and three unburned peatlands to assess the potential impacts of wildfire on massasauga overwintering habitat. We found that hummocks were able to provide unfrozen and unflooded habitat regardless of peat burn severity and that surface complexity and peatland-scale characteristics provided the greatest control on microhabitat suitability. This research highlights the importance of conserving peatland ecosystems that provide resilient species at risk habitat.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: The eastern massasauga rattlesnake is a species at risk native to Ontario and parts of the USA. In the eastern Georgian Bay region, massasaugas overwinter in wetlands for up to half the year. This is a sensitive period because flooding or freezing within the hibernacula can be fatal. Due in part to climate change, wetlands in this region are at increased wildfire risk which may threaten the quality of massasauga overwintering habitat. In 2018, a wildfire burned over 11,000 ha of land along eastern Georgian Bay, some of which was massasauga habitat. We monitored the water table position and soil temperature in potential massasauga overwintering habitat to assess its quality after wildfire. We found that wetlands provide unflooded and unfrozen habitat even when burned, and that wetland surface complexity is likely an important regulator of overwintering habitat quality. This research highlights the importance of identifying and protecting wetland ecosystems that provide resilient habitat in the face of a disturbance.