title: Improved Resonant Converters for Wide Voltage Range, High Current DC-DC and Universal AC-DC Applications

contributor:
Liu, Yan-fei
Liu, Yan-Fei
Electrical and Computer Engineering

subject:
Power Electronics
Power Converters
Resonant Converters
DC-DC
AC-DC
AC/DC

abstract:
Data centers are the cornerstone of business in modern society and individual lives. Of similar significance to daily life is the external AC-DC power supply exemplified by the cell phone charger. In both applications, power converters play the key role. As the demand for high-performance-and-small-size power converters increases, resonant converters, have become dominant in the data center power systems, and are gaining popularity in the cell phone charging market.
This thesis discusses three challenges in both applications – holdup issue, multiphase operation with current sharing in data center application, and universal AC input for the external AC-DC application. Aiming at these issues, several solutions have been proposed.
Specifically, sLLC converter is proposed for holdup applications, and LCLC converter can be used in both holdup and wide-input-voltage-range applications. Both technologies can extend the operational input voltage range of the conventional LLC converters, while have no impact on the performance of normal operation.
For the high current application, common-inductor and common-capacitor multiphase LLC converters are proposed to achieve current sharing without additional sensing and control. By adding one wire to connect the resonant inductors or the resonant capacitors in the conventional multiphase LLC converter, the current sharing performance can be improved from completely unshared to almost evenly shared.
Following the paradigm of the common inductor and common capacitor LLC converters, the impedance matching concept is proposed to model the coupled resonant tank with de-coupled components. With the proposed impedance matching concept, the current sharing mechanism is explained from the input impedance point of view, and more topologies with current sharing ability have been found.
For the universal AC-DC power supply, a new series resonant converter with capacitor bypassing method is proposed to significantly reduce the inductor size and loss. Besides, the performance is expected to improve thanks to the removal of switching loss and reduction of conduction loss as compared to existing technologies.
In this thesis, the proposed theories are verified by physical and mathematical analysis and computer simulations. Circuit prototypes are built to demonstrate the effectiveness and advantages of the proposed topologies and design methods.

abstract: PhD


title: Improving Communication Performance through Topology and Congestion Awareness in HPC Systems

contributor:
Afsahi, Ahmad
Electrical and Computer Engineering

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

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

rights: Intellectual Property Guidelines at Queen's University

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

subject:
HPC
Topology
MPI
Collective Communications
Neighborhood Collectives
GPU

abstract:
High-Performance Computing (HPC) represents the flagship domain in providing high-end computing capabilities that play a critical role in helping humanity solve its hardest problems. Ranging from answering profound questions about the universe to finding a cure for cancer, HPC applications span nearly every aspect of our life. The impressive power of HPC systems comes mainly from the massive number of processors---in the order of millions---that they provide. The efficiency of communications among these processors is the main bottleneck in the overall performance of HPC systems.

This dissertation presents new algorithms for improving the communication performance in HPC systems by exploiting the topology information.
We propose a parallel topology- and routing-aware mapping heuristic and a refinement algorithm that improves the communication performance by achieving a lower congestion across the network links. Our experimental results with 4,096 processors show that the proposed approach can provide more than 60% improvement in various mapping metrics compared to an initial in-order mapping of processes. Communication time is also improved by up to 50%.
We also propose four topology-aware mapping heuristics designed specifically for collective communications in the Message Passing Interface (MPI). The heuristics provide a better match between the collective communication algorithm and the physical topology of the system, and decrease the communication latency by up to 78%.

Furthermore, we expand topology-aware communications into the scope of accelerated computing. Using accelerators---especially Graphics Processing Units (GPUs)---to speed up certain types of computations plays an increasingly important role in HPC. We present a unified framework for topology-aware process mapping and GPU assignment in multi-GPU systems. Our experimental results on two clusters with 64 GPUs show that the proposed approach improves communication performance by up to 91%.

Finally, we present a novel distributed algorithm that uses the process topology information to design optimized communication schedules for MPI neighborhood collectives. The proposed algorithm finds the common neighborhoods in a distributed graph topology and exploits them as an opportunity to improve the communication performance through message combining. The optimized schedules reduce the communication latency of MPI neighborhood collectives by more than 50%.

abstract: PhD


title: Empirical Studies on Reducing Developers' Effort Spent on Resolving Software Issues

contributor:
Zou, Ying
Electrical and Computer Engineering

subject: Software Maintenance

abstract:
Software issue resolving process is one of the most frequent maintenance activities during the software development process. An issue tracking system (ITS) is often used to better manage the software issues. However, previous research work has shown that the issue resolving process needs development teams to put a large amount of effort to address the reported issues. When developers raise questions to clarify the description of issue reports during the issue resolving process, it takes time for developers to receive the response for the questions. Hence, the raised questions may negatively affect the efficiency of the issue resolving process. Moreover, a large proportion (e.g., 80% in Firefox) of the reported issues are rejected (e.g., the issue is not reproducible). The issue reports might exist in the ITS for a long time before they are rejected (e.g., over 50% of rejected issue reports are rejected after 6.73 days in Firefox). Even though these reports are rejected eventually, developers must have wasted valuable resources on triaging, inspecting and rejecting such reports.

In this thesis, we conduct two empirical studies to reduce the effort spent on the software issue resolving process. In the first study, we investigate how the process of resolving issues is impacted by the questions raised from the issue reports in the resolving process and apply machine learning techniques to predict if developers will raise questions from a new issue report. Our prediction result can give developers an early warning whether questions will be raised when the issue report is created. Developers can take proper actions to handle the issue reports that are likely to have questions raised, in order to improve the effectiveness of the issue resolving process. In the second study, we investigate the characteristics of issue reports that can be rejected by developers in the resolving process. We propose to prioritize the valid issue reports at higher positions and the predicted rejected issue reports at lower positions so that developers can put more effort on the valid issue reports.

abstract: M.A.Sc.


title: Towards improved life cycle assessment of environmental systems: geographical perspectives on multi-scale challenges in the context of bioenergy feedstock production

contributor:
Mabee, Warren
Mabee, Warren
Geography and Planning

subject:
LCA
Bioenergy
Life-Cycle Assessment
Modular Approach

abstract: Accurate environmental assessments can help inform landowners, policy-makers, and energy consumers about the risks or benefits of using biomass production for energy over other land-use options such as other renewable energy projects or food production. Life cycle assessment (LCA), a tool often used to assess the potential environmental impacts of bioenergy systems, faces ongoing issues associated with evaluating dynamic multi-scale systems. Although the importance of considering site-specific variation in LCA as geographies change has been identified for some time, adoption of geographical concepts in LCA has been slow to develop.  The aim of this thesis is to facilitate a discussion between geographic and LCA thought, and address what LCA approaches should look like when we need to evaluate environmental systems across a range of geographies, in the context of bioenergy feedstock production. An in-depth analysis of existing LCA standards reveal several areas in goal and scope directions where vague or absent instructions may lead to inappropriate use of geographical attributes by practitioners.  Using gaps identified in LCA standards, a systematic review of bioenergy LCA literature is performed over a ten-year period (2005 – 2015) to understand how spatial and temporal attributes of systems, input data, and scope definitions vary and may affect results when different LCAs are compared. Finally, using a modular multi-scale approach, a LCA of short-rotation coppice (SRC) willow is performed for a site in Guelph, Ontario, to evaluate modified LCA performance that incorporates geographic inputs over more traditional approaches to compiling inventories and evaluating impacts. The inclusion of smaller scale spatial and temporal attributes in the modular approach showed that improving data resolution can be used to address site-specific questions that more aggregated data cannot.  This thesis points towards a need to address issues of scale within LCA standards, particularly with respect to components of the scope such as data quality requirements.  Improving the transparency of geographical attributes of future LCAs provide an opportunity to document underlying characteristics of systems that may otherwise go unnoticed, but also provide a framework in which future dynamic LCA tools and models can be integrated.

abstract: PhD


title: Exploring Barriers and Facilitators to Clinical Practice Guideline Application in Mexican Mutual Aid Groups

contributor:
Levesque, Lucie
Lévesque, Lucie L.
Kinesiology and Health Studies

subject:
Chronic Diseases Management
Diabetes
Peer-Support
Physicians
Mexico

abstract: Introduction: The rate of lifestyle induced chronic diseases has increased rapidly over the last few decades. Diseases related to obesity such as Type 2 Diabetes, cardiovascular disease, and hypertension, have become leading causes of death worldwide. The effect of these diseases is becoming increasingly apparent in low and middle-income countries such as Mexico. In response to the rise in obesity and non-communicable diseases, the Mexican government enacted a policy called the Grupos de Ayuda Mutua (GAM), which looks to treat, manage, and prevent chronic diseases. A GAM is a peer-support group of patients with lifestyle-induced chronic diseases that receive guidance and oversight by a multidisciplinary group of health professionals. The health professionals are guided by evidence-based clinical practice guidelines (CPGs) to provide the best quality of care to their patients, however, when CPGs are applied in real world contexts, unforeseen challenges to adherence and application are observed (Larme & Pugh, 2001). Purpose: The purpose of this study is to explore the barriers and facilitators to CPG application from the perspective of physicians in Mexican GAMs. Methods: Working in collaboration with the Secretariat of Health in Jalisco, physicians (n = 24) were recruited to participate in semi-structured interviews, which were guided by the Clinical Practice Guideline Framework for Improvement (Cabana et al., 1999). Deductive thematic analysis was conducted to identify themes from the physician verbatim. Inductive analysis was used to identify facilitators to CPG application and recommendations from participants regarding how the GAMs and application of CPGs could be improved. Results: Physicians identified a variety of barriers and facilitators to CPG application in the GAMs. Barriers included lack of medication, lack of regional guidance, institutional culture, and more. Facilitators included creativity, seeing results, choosing the “right” patients, and more. Discussion: This study is one of the first to explore barriers and facilitators to CPG application in GAMs. Recommendations and considerations from participants on how the GAMs and application of CPGs could be improved are also reported. Study findings can be used by state health officials to improve the GAM strategy and facilitate the use of evidence-based methods in the GAMs.

abstract: M.Sc.


title: Self-Assembled Monolayers of N-Heterocyclic Carbenes on Gold and Silver:  Applications in Biosensing

contributor:
Crudden, Cathleen M.
Horton, J. Hugh
Chemistry

rights: Attribution-NonCommercial-NoDerivs 3.0 United States

subject: Silver Surface Chemistry, N-Herterocyclic Carbenes, Surface Chemistry

abstract: Modification of metallic surfaces using thiol-based self-assembled monolayers (SAMs) has been explored in the literature in the past three decades; silver surfaces less explored than gold. This technology has promise in many surface-based applications, specifically in micro electronics, sensors that use the surface plasmon resonance (SPR) phenomenon, and in catalysis. Unfortunately, the reactivity of silver towards sulfur means that thiol-based monolayers can form sulfide layers at the surface interface in atmospheric conditions making silver a troublesome metal for surface applications.  If sulfidization could be overcome, a robust SAM on silver might prove to be an effective tool for SPR, as silver is more sensitive to surface plasmon effects than gold, the current standard.  Our group has described a series of N-heterocyclic carbenes (NHC) which form SAMs on gold. As the carbene is attached to the surface via a metal-carbon bond, the problem of sulfidization may be overcome. Here, I describe the synthesis of a peptide for the application of heavy metal detection with the use of an NHC on a gold surface as well as the deposition and functionalization of silver surfaces with a series of NHCs, which might serve as appropriate candidates for use in an SPR sensor.  X-ray photoelectron spectroscopy (XPS) data show the NHCs chemisorb intact on the surface, and the stability of the films to oxidation are explored under a range of conditions.

abstract: M.Sc.


title: Dreamers and Critical Thinkers: Landscape as Narrative Strategy in  Contemporary Contiguous Fantasies for Children

contributor:
King, Shelley
English Language and Literature

subject: Children's literature

subject: Fantasy

subject: Landscape

subject: Charlie Fletcher

subject: Stoneheart

subject: Rick Riordan

subject: Philip Pullman

subject: R.L. LaFevers

subject: Egyptomania

subject: Space and Place in Children's Literature

subject: The Kane Chronicles

subject: His Dark Materials

subject: Theodosia

subject: Contiguous Fantasy

subject: Agency in Children's Literature

abstract: This dissertation focuses on a number of contemporary contiguous fantasies for children, books in which the fantastic is set in the real world of consensus reality. It explores how these texts deploy landscape and argues these contemporary novels use landscape as a means to subvert earlier conceptions of how children’s fantasy and children themselves interact with conceptions of place. Since children are often uncritically associated with the past and the primitive, this dissertation focuses on texts that subvert this paradigm by questioning what spaces children belong in, what places are appropriate for the uses of fantasy, and how past children’s fantasies have embraced nostalgia through their pastoral, rural, and pseudo-medieval landscapes. In the first chapter, I examine Rick Riordan’s Kane Chronicles and argue that Riordan’s text, by focusing on ancient Egyptian forms and structures within the North American landscape, privileges American spaces and places in a genre that has long been associated with European and British landscapes. My second chapter focuses on Charlie Fletcher’s Stoneheart trilogy, in particular its urban London setting, which takes the child out of the gardens and pastoral spaces of traditional British children’s literature and places the child protagonist within urban “Un-London” where the statues of the city are animate characters. Here, among all of London’s statuary, Fletcher’s text privileges statues that represent unexpected layers of that city’s deep palimpsest. My final chapter examines several texts including R.L. LaFevers’ Theodosia Throckmorton series and Philip Pullman’s The Subtle Knife to focus on children in the space of the museum, a space traditionally represented in children’s literature as a realm of adult authority. Rather than accepting the curation of the museum as static and unyielding, these texts offer examples of critical child consumers whose arcane and material knowledge of the artifacts questions the historical narrative that they represent. Through these readings, I argue that landscape (especially for children) is constructed just as childhood is constructed and each of these texts enacts a kind of curation that steps out of monolithic or uncritical nostalgic readings of time and place, interrogating both the place of the child in space and the way the past is presented to children.

abstract: PhD


title: The Workers’ War: The Character of Class Struggle in World War II

contributor:
Campbell, Peter
History

subject:
Labour
Industrial Relations
Canada
Left History
Socialism
Workers Self-Activity
Communist Party of Canada
CCF
World War Two
Working Class History
Strikes and Industrial Conflict
Mackenzie King
Welfare State
Racism, Nativism, and Xenophobia
Labour Unions
Radicalism

abstract:
This dissertation explores the nature of workers’ self-activity during World War II and the ensuing responses to these actions by the state and capital. A close examination of wartime strikes demonstrates that top-down efforts by unions to operate within normative industrial relations were generally failures. Far more likely to be effective were democratic strikes, generally illegal, called from the shopfloor. The Workers’ War further illustrates that while the government passed incredibly coercive legislation to control labour, such legislation failed to have a significant impact. Even where it was most influential and targeted it was eventually beaten through direct action. Even Japanese Canadian forced labour in work camps with armed guards, undertook effective strikes.

Largely interested in institutional and legislative changes, the unions, far from being a militant force, spent much of their energy trying to stop or curtail strikes. This thesis contends that the concretion of industrial legality in Canada was imposed to control effective action. Rather than breaking unions of their militancy, the dearth of a state terror apparatus necessitated the creation of compulsory bargaining legislation. First, it argues that the creation of the modern industrial relations regime that forms the foundation for modern labour law was the result of effective workers’ action rather than militant unions.
It further shows that the repressive apparatus of the state was unable to control workers, necessitating a structural adjustment. In a larger sense, this thesis argues that this story is at the centre of the history of capitalism in Canada. The imposition of capitalist social relations on the geographies that become Canada had the transformation of land into capital via labour at the very core of its project. Controlling labour was a central concern, and the manner in which labour relations were consolidated was a reflection of a negotiation between labour, capital, and state- a manifestly unequal negotiation that largely failed to reflect the interests of workers.

abstract: PhD


title: Philip Augustus and the Ideological Development of Sacral Kingship in Medieval France

contributor:
Husain, Adnan
History

subject:
History
Medieval France
Medieval historiography
Medieval kingship
Saint-Denis
Charlemagne
Philip Augustus

abstract: This paper aims to re-evaluate the place of Philip II “Augustus” in the canon of medieval French historiography, and seeks to examine his reign within the context of the development of an ideology of sacral Capetian kingship, as opposed to the more traditional interpretation of the rise of the political power of the Capetian dynasty. While acknowledging Philip’s crucial contribution to the emergence of medieval France as one of the pre-eminent political powers of Latin Christendom in the late thirteenth and fourteenth centuries, this paper argues that the wider historiographical field has diminished Philip’s equally important role in the construction of sacral Capetian ideology, presenting him as a proto-realpolitik monarch, rather than one overly concerned with spiritual or symbolic authority. In challenging the predominant historiographical portrayal of Philip II, this paper returns to an older tradition of scholarship embodied in historians such as Marc Bloch and Ernst Kantorowicz that emphasized both the sacerdotal understanding and representation of medieval monarchical power to contemporary theorists, and further argues that there existed a theoretical framework of uniquely Capetian sacral kingship that informed Philip’s most significant political and administrative reforms, and which he was intimately aware of and responding to. Moreover, Philip presided over the maturation of Capetian monarchical ideology through his own contributions in the patronage of the abbey of Saint-Denis, and a reinforcement of ties between the emergent Dionysian center of historical writing, the veneration of Saint Denis, and the Capetian monarchy. Alongside this development, Philip’s reign saw the revival and incorporation of Carolingian symbolism and nomenclature into the canon of Capetian monarchical conventions, which enhanced the sacral reputation of the Capetian dynasty and legitimized the dramatic expansion of political and territorial authority that characterized Philip’s rule. Ultimately, Philip’s contribution to an ideology of sacral Capetian kingship was highly significant in that it saw the emergence of a nascent understanding of a communal identity of Franci in Francia, united under the figure of the sacral Capetian king and through shared ethnic, linguistic, and religious historical heritage, which would come to full fruition during the reigns of Louis IX and Philip IV.

abstract: M.A.


title: Discovery of Patterns in Simulink Systems

contributor:
Dean, Thomas
Dean, Thomas R.
Computing

subject:
Simulink Modeling Patterns
Pattern Search Algorithms
pattern elicitation techniques
Pattern Detection Software Tools
Embedded Systems
Empirical Analysis

abstract:
Model-Driven Engineering tools and techniques have become mainstream aids in the development
of embedded cyber-physical systems. The large-scale use of visual models is a powerful
paradigm for designing reliable and maintainable systems assembled with complex hardware, software
and mechanical elements. Modular design approaches can readily capture the requirements
for embedded systems into executable and evolutionary models.

We propose a framework to discover, classify and visualize model-patterns in large repositories of
Simulink models. We design, and implement in a software toolchain, a set of scalable algorithms to
fully traverse and contextually parse the source code of these repositories in order to compute topology
hash functions for the size, name connectivity and type connectivity of each model subsystem,
as well as properties of Stateflow charts. We use these extracted properties to cluster the subsystems
into a set of addressable-by-property classes. We develop an interactive model visualization and
querying facility, embodied by the MoSART user interface, to identify further relations, similarities
and abstractions in the elements of the cluster classes. This tool provides a configurable environment
for inferring structural model-patterns and elaborating on semantic model-patterns with the assistance
of skilled domain knowledge. We propose a query system, based on regular expressions that
match values of previously computed subsystems properties, as an effective method to iteratively
refine Simulink model-patterns abstractions into accumulated modeling knowledge.

Our implementation works cooperatively with a 3-phase iterative model-pattern discovery approach
that we conceptualize as 1) model clustering: repository traversal and subsystem-topology
evaluation for clustering subsystems, 2) primary model-pattern inference: visualization, querybased
search and clustering for identifying basic semantic patterns, 3) model-pattern refinement:
continuous refinement of basic patterns into specialized groups for application in targeted use cases.
We effectively support the iterative nature of this approach because our repository traversal, property
evaluation and clustering algorithms have low time-complexity, that is, between a lower-bound(n) and
O(n lg n)(n = total lines of source code in a repository), and our interactive tool provides a
complete-coverage view of a model repository.

abstract: PhD


title: Associations Between Exposures to Nature and the Occurrence of Psychosomatic Symptoms Among Canadian Adolescents

contributor:
Pickett, William
Public Health Sciences

subject:
Psychosomatic Symptoms
Outdoor Play
Nature Connectedness
Adolescence

abstract:
Background: Spending time outdoors and connecting with nature are beneficial for the physical and mental health of humans. Nature has been associated with promotion of positive mental health through stress reduction and multiple other pathways. Much of the work on this topic has focused on adult populations. The ways that nature may relate to the mental health of young people represents an important gap in knowledge.

Objectives: Using a large, nationally representative sample of Canadian adolescents, the objectives of this thesis were: 1) to examine the association between outdoor play and psychosomatic symptoms; 2) to examine the association between perceived importance of nature connectedness and psychosomatic symptoms; and 3) to determine whether these associations were dependent on sex and/or age.

Methods: In an analysis of data collected from young Canadians in 2013/2014, I described the prevalence of outdoor play, perceived importance of nature connectedness, and psychosomatic symptoms. Next, I developed a series of log-binomial regression models to quantify associations between the exposures to nature and the outcome in the form of relative risks and 95% confidence intervals. After accounting for relevant confounders in the models, sex and age were tested as effect modifiers.

Results: The association between outdoor play and psychosomatic symptoms was found to be modified by sex but not age group. Among female adolescents, playing outdoors for at least 30 minutes/week was associated with a 24% (95% CI: 5%, 40%) reduction in the prevalence of high psychosomatic symptoms compared to those reporting no weekly outdoor time. Among males, there was no statistically significant relationship between outdoor play and psychosomatic symptoms. The association between perceived importance of nature connectedness and psychosomatic symptoms did not differ according to sex or age. Perception of connection to nature as ‘important’ was associated with a 25% (95% CI: 9%, 38%) reduction in the prevalence of high psychosomatic symptoms compared to those who perceived connection to nature as ‘not important’.

Conclusion: This study highlights the importance of adolescent engagement with nature as one strategy to promote their psychological well-being. It also emphasizes the importance of accounting for differences between the sexes when researching, planning, and implementing public mental health initiatives that consider exposure to the outdoors.

abstract: M.Sc.


title: Role of STAT1 in Disease Progression and the Tumour Immune Microenvironment of High-Grade Serous Ovarian Cancer

contributor:
Koti, Madhuri
Craig, Andrew
Biomedical and Molecular Sciences

subject:
Ovarian Cancer
Tumour Microenvironment
Immunoreactive
Chemoresistance
Tumour Infiltrating Lymphocytes
STAT1

abstract: Ovarian high-grade serous carcinomas (HGSC) are the most common and fatal histological subtype of ovarian cancer, characterised by late stage diagnosis and high mortality rates. Unfortunately, the majority of patients (> 85%) will develop fatal chemoresistant disease despite multiple lines of treatment. Recent studies investigating the tumour immune microenvironment have highlighted the prognostic significance of different tumour infiltrating lymphocyte (TIL) subsets and secreted immune factors in HGSC. However, the mechanisms promoting TIL recruitment to the tumour epithelial compartment, where they show the most benefit, remain poorly understood in HGSC. It is known that alterations and activities of TILs are mediated by the interaction of various cytokines and growth factors in the tumour microenvironment (TME). Signal transducer and activator of transcription 1 (STAT1) is activated in response to interferon signalling and upregulates cytokines responsible for the recruitment of TILs to the TME. Building on previous findings linking STAT1 expression to a pre-existing immunoreactive TME and improved clinical outcome in HGSC, the current study investigates the role of cancer cell intrinsic STAT1 expression in regulating an anti-tumour immune microenvironment and disease progression in HGSC. Immune transcriptomic analysis of HGSC patient tumours indicates a significant downregulation of immune related genes in chemoresistant patients with low-STAT1 expression. Functional studies confirmed STAT1 as a positive regulator of anti-tumour immune responses in the TME through its role in cytokine signalling and TIL recruitment. In vitro experiments revealed that decreased STAT1 expression is associated with increased cancer cell proliferation, invasion and migration. In vivo experiments in a syngeneic mouse model of HGSC revealed that decreased STAT1 in the TME increased disease burden and led to decreased infiltration of CD8+ TILs. These findings are important for the design of immune based therapies to improve chemotherapy response and overall survival in HGSC patients. Further work is required to identify appropriate immunotherapy and chemotherapy combinations for HGSC patients based on their immune profiles.

abstract: M.Sc.


title: Comprehensive Modelling for Eddy Current Based Pressure Tube to Calandria Tube Gap Measurements

contributor: Physics, Engineering Physics and Astronomy

subject:
Applied Physics
Eddy Current
CANDU
PT-CT Gap
Non-Destructive Testing

abstract: The separation between the pressure tube (PT) and calandria tube (CT), known as gap, in the CANada Uranium Deuterium (CANDU®) nuclear reactor fuel channels is monitored using a drive-receive eddy current probe. Gap measurement accuracy is crucial to ensure contact does not occur between the PT and CT, as contact can lead to cracking of the PT. Variation of in-reactor parameters can compromise gap measurement accuracy. Validated models of the eddy current response to changes in gap can be used to help identify parameters whose variations most affect gap measurement accuracy. However, current models are limited, since they assume the PT and CT are infinite parallel conductive plates, thereby, neglecting the potential effects of PT and CT curvature. Finite Element Method (FEM) models of flat-plate geometry, true PT-CT gap probe geometry, and concentric tube geometry were developed to explore how different geometric approximations can model gap response. The concentric tube geometry, where the CT remains axially concentric with the PT, accurately accounted for curvature of the PT and varied gap by changing the radius of the CT, had the possibility of an analytical solution. Comparison between the three FEM models and experimental measurements showed that both curved models gave similar accuracy and were more accurate than the flat-plate geometry model. A Second Order Vector Potential (SOVP) formalism was used to develop a semi-analytical model of the concentric tube geometry. This semi-analytical model was shown to be three to five times more accurate than the analytical flat-plate model, when compared with experimental measurements for varying PT wall thickness and resistivity. Using the semi-analytical concentric model, a sensitivity analysis was performed to evaluate which parameter variations had the largest effect on gap measurements. It was shown that variations in liftoff had the largest effect on predicted gap and were approximately two to three times more influential than the next most sensitive parameter variation, PT wall thickness. The analysis demonstrated the necessity for accurate PT wall thickness measurements, currently obtained by ultrasonic techniques. Variation of PT resistivity was the next most significant, a parameter whose variation is currently uncompensated for in PT to CT gap measurements.

abstract: M.A.Sc.


title: Objectively measured active transportation among 10-13 year olds from Kingston, Ontario

contributor:
Janssen, Ian
Public Health Sciences

subject:
Active Transportation
Built Environment
Walkability
Children and Youth

abstract:
Background:
Active transportation positively influences the physical and mental health of children and adolescents. Research on active transportation to school suggests that the walkability of the built environment can influence active transportation. Traditionally, active transportation within children and adolescents has been measured using questionnaires and has focused almost exclusively on the trip to school.
Objectives:
This thesis studied 10-13 year olds from Kingston, ON and the objectives were to 1) use objective measures to describe children’s total active transportation and active transportation to common travel destinations, and 2) examine the relationship between neighbourhood walkability and children’s active transportation to different destinations.
Methods:
This was a cross-sectional study of 388 children and early adolescents (aged 10-13 years) from Kingston, ON, Canada. Participants wore a Garmin GPS watch during waking hours for seven consecutive days. GPS data was analyzed using the Personal Activity Measurement Location System (PALMS) software which identified trips, the time spent in each trip and the trip modality (walking, bicycle, or vehicle). GIS measures of connectivity, proximity to destinations, and pedestrian infrastructure and safety were used to create a walkability index within a 1 km travel distance of each participant’s home.
Results:
Mean time spent in active transportation was 11.0 minutes/day (95% CI: 10.6, 11.5). Time spent in active transportation was higher for boys (12.4 minutes/day [95% CI: 11.8, 13.1]) than for girls (9.5 minutes/day [95% CI: 9.0, 10.1]) and increased from 8.6 minutes/day (95% CI: 8.0, 9.2) at age 10 to 15.4 minutes/day (95% CI: 14.4, 16.3) at age 13. Time spent in active transportation was lower in the winter by comparison to the other seasons. The most common active transportation destinations were the participant’s home, their school, and other people’s homes. Those living in neighbourhoods in the highest walkability quartile spent an average of 16.2 minutes/day (95% CI: 14.9, 17.5) in active transportation while those in the lowest quartile spent an average of 6.3 minutes/day (95% CI: 5.7, 6.8) in active transportation.
Conclusion:
Boys engaged in more active transportation than girls, active transportation increased with age and winter was the season with the least active transportation. Home, school and other people’s homes were the destinations with the most active transportation minutes. Those living in the most walkable neighbourhoods accumulated nearly three times more active transportation than those living in the least walkable neighbourhoods.

abstract: M.Sc.


title: Production of Multi-Purpose Bio-Solid Feedstock for Oxidation in Cement Calciner using Microalgae

contributor:
Zeman, Frank
Chemical Engineering

subject:
Microalgae
Dewatering
Electrocoagulation
Multi-Purpose Bio-Solid

abstract:
The concentration of carbon dioxide (CO2) in the atmosphere is rising and its impact (e.g. climate change) is established among the scientific community. Fuel switching in commercial sectors (e.g. cement plants) is one method to reduce fossil CO2 emissions. Microalgae cultivation provides an opportunity to reduce CO2 via photosynthesis and to produce biomass crop for fuel-switching. Industrial scale production of environmentally sound fuel using microalgae systems is still a challenge due to the small cell size and the low concentration in the growth culture.  This study investigates a dewatering approach consisting of electrocoagulation, gravity sedimentation, sand filtration, briquetting and passive drying to harvest the algal bio-solids and to produce a multi-purpose feedstock for use in cement plants.
The microalgae suspension in solution is first destabilized via electrocoagulation by means of charge neutralization and micro-bubble flotation. The highest destabilization achieved at 15 Amp/m2 using aluminum and iron anodes, with 60 min of operational time, were 90% and 48% respectively. The variation of solution pH and stirring speed had no noticeable effects on the overall performance. Further densification of algal bio-solids took place in a sedimentation vessel in which 92% of the process water was removed, allowing for recycling, and the water content was concomitantly reduced from 99.88% to 99.24%.  The algal bio-solids obtained after a combined treatment of electrocoagulation and sedimentation were characterized using ICP-OES, TGA, and bomb calorimeter. The metal hydroxides (i.e. aluminum and iron) contribute in the reduction of raw materials used in cement making. Limestone micro-aggregates were employed as filter medium to reduce the water content of pre-concentrated algal solution from 99.24% to 93.45%, removing 84% of the entrained water.  Multi-purpose briquettes were prepared from algal cake, containing metal hydroxides, and a portion of the filter bed, where the water content further reduced to 65% due to the limestone blending. The water content of the briquettes was reduced to less than 15% within few days under ambient condition (i.e. passive drying).  Full substitution of calciner fuel leads to 4% of CO2 reduction compared to coal, and enhances biogenic carbon dioxide (bCO2) generation which accounts for 18% of the total CO2 emissions.

abstract: M.A.Sc.


title: Improving Metabolic Monitoring and Promoting Safe Use of Second-Generation Antipsychotics in Children and Adolescents

contributor:
Tregunno, Deborah
Goldie, Catherine
Nursing

subject:
Metabolic Monitoring
Antipsychotics
Nursing
Child and Adolescent Psychiatry
Drug Safety
Guidelines
Multidisciplinary Collaboration

abstract:
Background: Second-generation antipsychotics (SGAs) are increasingly being used for
the treatment of child and adolescent mental health problems causing concern as there is limited
evidence of their safety in this population. SGAs are known to cause metabolic, cardiac and
endocrine side effects which may have an amplified effect in youth in periods of growth and
development. Metabolic monitoring guidelines from the Canadian Alliance for Monitoring
Effectiveness and Safety of Antipsychotic Use in Children (CAMESA) exist to guide practice in
the prevention and detection of metabolic instability in pediatric SGA users. However, reported
rates of metabolic monitoring are inadequate. Evidence of rates and factors associated with
metabolic monitoring of youth on SGAs in Canada is limited and the extent to which the
CAMESA guidelines are adhered to is not known.
Methods: A retrospective chart review analysis of 294 children and adolescents in an
outpatient psychiatry setting was conducted to assess baseline and follow-up metabolic
monitoring, demographic, treatment and healthcare utilization variables in a one-year period of
interest within a two-year study period (2014-2016).
Results: Metabolic monitoring did not adhere to CAMESA guidelines and was poor over
a 1-year period. 23.5% (n=69) of participants had any monitoring documented at baseline and
22.8% (n=67) had any follow-up monitoring. There were significant differences in between
children (ages 4-12, n=99) and adolescents (ages 13-18, n=195). In adolescents, the factors
associated with metabolic monitoring documented at baseline were a higher number of psychiatry
visits (OR 1.2, 95% CI 1.10-1.41), longer duration of contact (OR 14, 95% CI 2.31-82.4), and
prescription of medications in addition to SGA (OR 3.2, 95% CI 1.17-8.94) while in children,
factors were having an emergency room visit (OR 3.4, 95% CI 1.01-11.71) and taking
aripiprazole as the type of SGA for treatment (OR 7.4, 95% CI 2.02-27.45).
Conclusion: Findings from this study support existing literature of inadequate metabolic
monitoring of children and adolescents on SGAs and calls for further investigation into factors
associated with metabolic monitoring. Recommendations to improve metabolic monitoring in this
context include multidisciplinary collaboration and enhancement of the nursing role as a
pragmatic approach in improving care for this population.

abstract: MNSc.


title: Eastern Ontario Pre-Service Intermediate-Senior Mathematics Teachers' Beliefs About Problem Solving

contributor:
Pyper, Jamie
Education

subject:
Problem Solving
Mathematics Education
Mixed Methods
Pre-Service Teacher Education

abstract:
Problem solving in the Ontario mathematics curricula is described as central to learning mathematics. Scholars of mathematics education similarly stress the importance of problem solving, noting its potential to develop students’ academic ability in mathematics and prepare students to be effective lifelong learners. However, despite the value attributed to problem solving in the learning of mathematics, little is known about how pre-service teachers are thinking about problem solving. Given that beliefs are a fundamental domain of cognition, the first step in addressing this gap in the literature is to explore pre-service teachers’ beliefs about problem solving. Hence, the purpose of this mixed methods study was to explore Eastern Ontario pre-service intermediate-senior mathematics teachers’ beliefs about mathematics problem solving.

Following a pragmatic mixed methods approach, quantitative questionnaire data were collected from a sample of 44 pre-service teachers in an Eastern Ontario teacher education program, and qualitative interview data were collected from a subsample of four pre-service teachers. Both types of data were collected at the beginning and end of the Fall 2016 academic term. Analysis followed a convergent parallel design, where quantitative and qualitative data were analyzed separately then merged to enable the identification of key features being converged upon by the two data sets.

Analysis of the qualitative interview data identified and described the pre-service teachers’ ontological and epistemological beliefs about mathematics problem solving (i.e., beliefs about what mathematics problem solving is and how mathematics problem-solving knowledge is acquired, respectively). Additionally, analysis of the quantitative questionnaire data identified statistically significant differences in the pre-teachers’ beliefs about problem solving with respect to experience in the teacher education program and teacher-related variables. Finally, by comparing and integrating the questionnaire and interview findings, it was possible to characterize the prominent features of problem solving the pre-service teachers emphasized when communicating their thoughts about problem solving. The implications for mathematics educators focus on opportunities for recognizing the complex conceptualization of problem solving espoused by pre-service intermediate-senior mathematics teachers. Recommendations for future research highlight the need to expand the scope of this initial investigation and to investigate pre-service teachers’ knowledge of problem solving.

abstract: M.Ed.


title: Disruption of hERG Channel Function by the Uremic Toxin p-Cresol

contributor:
Zhang, Shetuan
Biomedical and Molecular Sciences

subject:
Cardiac Electrophysiology
hERG
Uremic Toxins

abstract: The human ether-a-go-go-related gene (hERG) encodes the rapidly activating delayed rectifier potassium channel (IKr), which is critical for cardiac repolarization. A reduction in hERG current can cause long QT syndrome (LQTS), leading to potentially fatal cardiac arrhythmias. In Chronic Kidney Disease (CKD), the risk of sudden cardiac death (SCD) is increased beyond what is explicable by traditional risk factors for cardiovascular disease. The molecular mechanisms governing CKD-induced cardiac arrhythmias are unknown, but a significant portion of CKD patients have prolonged QT intervals. In CKD, a large number of compounds, which would normally be excreted by the kidneys, are progressively accumulated. These compounds are known as uremic toxins and have been shown to negatively affect a variety of biological functions. Serum concentrations of the uremic toxin p-Cresol (pC) increase exponentially in CKD patients. Increased pC has been correlated with QT interval prolongation in patients, but no causative link has been established. Impairment of hERG function is a common cause of LQTS, so we investigated the effects of pC on hERG protein expression and current. We found that pC chronically reduces both hERG current and protein expression at the plasma membrane. Our findings suggest that pC acts through a Nedd4-2 dependent mechanism to decrease hERG. Our results from stable hERG-HEK cells are corroborated with data collected from cultured neonatal rat ventricular myocytes. We also demonstrate in an in vivo rabbit model that pC injection results in a prolongation of the QT interval. The results presented in this study suggest that pC may play a role in CKD-related LQTS.

abstract: M.Sc.


title: Role of Neuraminidase-1 in Cancer Development and Clinical Implications

contributor:
Szewczuk, Myron
Biomedical and Molecular Sciences

subject:
Neuraminidase
Growth Factor Receptor
Cellular Signaling
Glycobiology
Receptor Glycosylation
Sialic Acid
Human Cancer

abstract:
The abnormal expression of cell surface sialic acid has recently been identified as an important trait of cancer cells. The main sialylation-modifying enzyme in mammalian cells, neuraminidase-1 (Neu1), has been shown to positively regulate several receptors and their activation, including the epidermal growth factor receptor (EGFR), insulin receptor (IR), and a number of TOLL-like receptors (TLR). Notably, these receptors each play unique and profound roles in tumor development and progression via promotion of cell proliferation and survival pathways, cell growth and metabolism, and immune-mediated tumorigenesis, respectively. Here, we further characterize the role of Neu1 in cancer cell signaling, as well as tumor growth, neovascularization and metastasis. Furthermore, the molecular targeting of Neu1 using competitive inhibitor and sialic acid analog oseltamivir phosphate (OP) has been evaluated for its therapeutic role in suppressing tumor progression.

This report uncovers the molecular mechanisms that regulate the role of Neu1 sialidase in insulin receptor activation. Specifically, we show that GPCR agonists bombesin, bradykinin, angiotensin I and angiotensin II can stimulate Neu1 sialidase activity to induce IR activation (phosphorylation) in the absence of insulin. Furthermore, this effect can be blocked by GPCR inhibitor BIM-23127 as well as OP.

The studies in this report also investigated the effect of OP in murine models of human triple-negative breast cancer (MDA-MB-231), ovarian endometrial cancer (A2780), and pancreatic ductal adenocarcinoma (PANC1) tumor xenografts growing in RAGxCγ mice. In comparison to untreated groups, OP treatment resulted in a significant reduction in tumor volume, metastatic spread to the mouse liver and lungs, as well as a reduction in tumor-associated neovascularization and recruitment of host endothelial cells. In conclusion, these findings provide insight into the novel targeting of tumor-promoting pathways via Neu1 sialidase and implicate OP as a novel agent in cancer therapy.

abstract: PhD


title: Exploring Relations between Korean Test Takers' Anxiety and Performance on the Test of English for International Communication in Listening and Reading Comprehension (TOEIC LR)

contributor:
Cheng, Liying
Education

subject:
Anxiety
Test Anxiety
Foreign Language Anxiety
Language Test Performance
Korean Test Takers
TOEIC LR

abstract:
Test anxiety and foreign language anxiety can affect test takers’ performance on a high-stakes foreign language proficiency test, such as the Test of English for International Communication in Listening and Reading comprehension (TOEIC LR). As
the TOEIC LR is most widely used in South Korea (henceforth, Korea), that country presents a meaningful research context to examine this test. However, despite the TOEIC LR’s widespread use, no previous studies have directly examined the relationships between test takers’ anxiety and their performance on this test. Therefore, the present study investigated the extent to which test anxiety and foreign language anxiety influenced Korean test takers’ performance on the TOEIC LR.
          Data were collected from 226 Korean test takers who were university students or graduates in need of TOEIC scores for high-stakes decisions, including graduation and/or employment. Participants completed a questionnaire asking for demographic information and levels of cognitive test anxiety, foreign language reading anxiety, and foreign language listening anxiety. Additionally, they provided their TOEIC scores. Correlational analyses, MANOVA, and multiple regression analyses were conducted to answer the proposed research questions.
          The two foreign language anxieties formed greater correlations with each other than either did with cognitive test anxiety, suggesting conceptual overlap between the domains of these foreign language anxieties. In terms of predicting language test scores, foreign language anxieties specific to language skills were more effective than cognitive test anxiety. The influence of cognitive test anxiety on TOEIC scores was insignificant when foreign language anxieties were included in the regression model.
          This study contributes to a finer understanding of the relationship between test anxiety and foreign language anxiety in the Korean context by including all three of the anxiety constructs into a single investigation. Furthermore, this study sheds light on the extent to which Korean test takers’ test anxiety and foreign language anxiety affect their performance on a high-stakes English proficiency test. Based on these findings, future research should discuss whether or not test takers’ anxiety should be included in test validation and investigate the extent to which test takers’ anxiety threatens validity of test score interpretations as possible sources of construct-irrelevant variance.

abstract: M.Ed.


title: Assessment for Learning Explored in Grade 9 Applied Mathematics Classrooms

contributor:
Klinger, Don Albert
Education

subject:
Assessment for Learning
Secondary Mathematics
Mathematical Knowledge for Teaching
Conceptions of Assessment for Learning
Education

abstract:
Despite the focus on assessment for learning (AfL) across Canada, the use of AfL across classrooms is not routine practice. Existing literature has found that secondary mathematics teachers implement AfL strategies along a continuum, from no implementation to deep integration in the classroom. AfL is valuable for all students, and in particular, struggling students may be the strongest beneficiaries of AfL. As a result, my dissertation explored secondary mathematics teachers’ use of AfL strategies with students who may struggle in mathematics, and the extent that there exist systematic differences in the integration of these strategies across classrooms of varying school-achievement results. Three research questions guided this study: (a) What is the nature of teachers’ AfL strategies? (b) What are the relationships between teachers’ AfL strategies and AfL conceptions? and (c) What are the relationships between teachers’ AfL strategies and mathematical knowledge for teaching (MKT)?
Across Southern Ontario, a teacher questionnaire was administered (N = 131) and case studies (N = 4) were conducted with teachers of Grade 9 applied mathematics (G9APM). The schools in which these teachers taught were categorized as one of three achievement categories—high, average, or low—based on their school-achievement results. School-achievement results were either determined by a school’s average Education Quality and Accountability Office result for students in G9APM or a self-reported measure. Data analyses included the use of descriptive and inferential statistics, correlational-based analyses, and deductive and inductive qualitative thematic analyses.
Research findings illustrate: (a) no differences in teachers' AfL strategies, AfL conceptions, or MKT, across school-achievement results; (b) teachers commonly implemented the letter of AfL and had a teacher-centric conception of AfL; and (c) AfL strategies are connected to MKT. Specifically, MKT supported AfL practices, namely identifying and sharing success criteria, engineering effective classroom discussions and tasks that elicit evidence of learning, and providing feedback that moves learners forward. Findings highlighted that teachers require domain specific pedagogical support in implementing the spirit of AfL.

abstract: PhD


title: Disease, Sex and Evolution

contributor:
Day, Troy
Mathematics and Statistics

subject:
Evolution
Mathematical Biology
Infectious Disease

abstract: This thesis focuses upon some evolutionary problems related to sexual reproduction and disease. We first consider whether we should expect a fundamental difference between the outcomes of pre- and post-copulatory sexual conflict, and whether an informational asymmetry exists between the sexes. We then examine how sexually-transmitted infections can create selective pressures upon the evolution of mating systems, with a particular focus upon serial monogamy. We also consider more generally how pathogens can shape intraspecific interactions (by host avoidance), and how in turn host avoidance can alter the selective environment for pathogens. Finally, we examine how epidemiology and finite population size can interact to alter the evolution of sterility virulence, providing a novel explanation for why sterility virulence is more commonly associated with sexually-transmitted infections.

abstract: PhD


title: Bi-directional Association between Sleep and Outdoor Active Play among 10- to 13-year-olds

subject:
Children
Sleep
Play
Epidemiology
Public Health

abstract:
Purpose: The purpose of this study was to investigate whether there is a bi-directional relationship between sleep characteristics (time in bed, sleep duration, sleep efficiency) and outdoor active play (OAP) within children.

Methods: Participants consisted of 433 children aged 10-13 years. Time in bed, sleep duration, and sleep efficiency were measured for 8 consecutive nights using data from a sleep log and Actical accelerometer. OAP was measured for the 7 days that fell in between these 8 nights using a combination of data from accelerometers, global positioning system (GPS) loggers, and geographic information system (GIS). Generalized estimating equation (GEE) models with first-order autoregressive matrix [AR(1)] were used to assess the relationships of interest. These models accounted for the repeated measures nested within participants and adjusted for several confounders.

Results: Time in bed, sleep duration, and sleep efficiency were not significantly associated with the following day’s OAP. There was a small but significant (p = 0.017) association between OAP and the following night’s time in bed, which suggested that each hour increase in OAP was associated with a 5.1 minute (95% CI: 0.9 - 9.4) increase in time in bed. OAP was not significantly associated with sleep duration or sleep efficiency.

Conclusions: None of the sleep characteristics predicted the following day’s OAP. Higher levels of OAP predicted a longer time in bed, but not sleep duration or sleep efficiency.

abstract: M.Sc.


title: Relationships Between Winter Energetic Condition and Reproductive Investment in a Wild Bird

contributor:
Bonier, Frances
Biology

subject:
Reproduction
Hormone
Carry-Over
Winter
Chickadee
Parental Care
Oxidative Stress
Corticosterone
Life History
Breeding

abstract: Reproduction is an energetically demanding life history stage that comprises costly physiological and behavioural changes. Despite these costs, some individuals invest more in reproduction, and breed more successfully than others. To understand variation in reproductive investment, studies often evaluate factors during breeding, but conditions outside of the breeding season may also play a role. These linkages across life history stages remain poorly understood, particularly at the mechanistic level. Using wild populations of black-capped chickadees (Poecile atricapillus), we evaluated whether traits relating to energetic condition (i.e., circulating corticosterone concentrations, oxidative balance, haemolytic complement activity, and body condition) during the non-breeding season predicted reproductive investment in the subsequent breeding season. Winter haemolytic complement activity did not predict subsequent breeding investment. However, we found that females with high winter fat scores laid eggs sooner and fed their offspring more often, and females with high winter corticosterone concentrations produced lighter eggs. We also found that males with high winter oxidative stress had smaller clutches, that males with high winter fat fed their offspring more often and had nestlings with lower baseline corticosterone, and that males with high winter corticosterone concentrations had lighter eggs and smaller nestlings in the brood produced by their mate. These winter energetic traits may relate to reproductive investment via carry-over effects across seasons, and/or because they reflect an individual’s phenotypic quality. Altogether, our findings suggest that in wild populations, conditions experienced outside of the breeding season may be important factors explaining variation in reproductive investment, even in a resident species. These linkages between life history stages could have important implications for the study of population dynamics, particularly in declining populations.

abstract: M.Sc.


title: 'Helping People Help Themselves': Democracy, Development, and the Global Politics of Poverty in Canada, 1964-1979

contributor:
Dubinsky, Karen
McKay, Ian
History

subject:
development
democracy
poverty
Canada in the World
global Sixties

abstract:
For a remarkable period between the late 1950s and mid-1970s, a global politics of poverty emerged.  Prompted by anti-imperialist struggles, working class demands, social and cultural ferment, and socialist alternatives, the politics turned on how to alleviate global poverty – and to what ends.  It had different manifestations, but contained shared core insights and practices.  It did not simply animate the international sphere, but permeated national, regional, and local politics as well.  In this context, some Canadian liberals believed that development would contribute to the elimination of poverty, internationally and domestically, by involving people more fully in the values, economic processes, and political practices of liberal capitalist democracy.  Community development, regional development, and international development emerged as concurrent, if contested, schemes to revitalize liberal democracy within and beyond Canada’s borders.
	This study is a political history of the relationship between poverty, democracy, and development in Canada in the 1960s and 1970s within a larger global frame.  Through a focus on development programs across three scales, I trace the on-the-ground activism of reformers and radicals in dialogue with the global context in which they consciously rooted their work.  The focus of the local scale is the community development and animation sociale activities of Company of Young Canadians (CYC) in Lesser Slave Lake, Alberta and St-Henri, Montreal.  On a regional scale, I examine the efforts of Cape Breton Development Corporation (DEVCO) to address regional inequality and poverty.  Adopting an international scale allows us to focus on the Third World international development activity of Canadian University Service Overseas (CUSO) – namely, its project in Tanzania.  I argue that liberal reformers, amid exchanges with a New Left, created and committed to development programs they believed would empower people, both in Canada and abroad, to confront their own poverty and foster a meaningful democracy rooted in everyday life.  However, development programs – having stopped short of amending capitalist social relations and the political and economic hierarchies they engendered – realized neither their anti-poverty nor democratic goals.

abstract: PhD


title: A Polya Urn Stochastic Model for the Analysis and Control of Epidemics on Networks

contributor:
Alajaji, Fady Jr
Gharesifard, Bahman Jr
Mathematics and Statistics

rights: Attribution-NonCommercial 3.0 United States

subject:
Epidemics
Networks
Polya Urn Model
Control of Networks
Optimization
Stochastic Processes

abstract: This thesis introduces a model for epidemics on networks based on the classical Polya process. Temporal contagion processes are generated on the network nodes using a modified Polya sampling scheme that accounts for spatial infection among neigh- bouring nodes. The stochastic properties and asymptotic behaviour of the resulting network Polya contagion process are analyzed. Given the complicated nature of this process, three classical Polya processes, one computational and two analytical, are proposed to statistically approximate the contagion process of each node, demon- strating a good fit for a range of system parameters. An optimal control problem is formulated for minimizing the average infection using a limited curing budget, and a number of different curing strategies are presented, including a proven conver- gent gradient descent algorithm. The feasibility of the problem is proven under high curing budgets by deriving conservative lower bounds that turn some processes into supermartingales. Extensive simulations run on large-scale networks demonstrate the effectiveness of our proposed strategies.

abstract: M.A.Sc.


title: Consumer Search, Sentiments and Firm Heterogeneity

contributor:
Feng, Ying
Economics

subject:
Labor Productivity
Labor Share
Inequality
Search Theory
Firm Heterogeneit

abstract: This thesis contributes to our understanding of variations in labor productivity over the business cycle, and the long run decline in labor income share. Chapter 2 develops and analyzes a general equilibrium model with goods’ market frictions, heterogeneous ﬁrms, and consumer sentiments. I use the model to demonstrate that the interactions among these features of the model leads to new and interesting results. Firstly, average product of labor can be positively or negatively related to expected real income. Secondly, under certain conditions, lower priced ﬁrms not only sell to a larger market, but also have higher markups. Lastly, ﬁrm level pass through of ﬁrms’ idiosyncratic shocks and sentiment shocks, their elasticities of output and employment with respect to sentiment shocks can be complex. Chapter 3 constructs a stochastic general equilibrium model in which business cycles are driven by changes in sentiments to explain the Labor Productivity Puzzle. In recessions, increased search by consumers - an endogenous rise in the average number of prices observed by consumers - causes expenditures to be reallocated to the more productive ﬁrms. This eﬀect causes employment to fall relative to output and increases APL. At the same time, less productive ﬁrms can also be insulated from a fall in demand by lower marginal labor costs during the recessions. This eﬀect causes employment to rise relative to output and decreases APL. In calibrated versions of the model, I ﬁnd that the former eﬀect dominates over time and the theory is able to explain over three quarters of the decline in the fall in the volatility of APL and a sizable decline in the volatility of employment. Chapter 4 studies the causes of labor share decline in the retail sector. I provide microeconomic evidence that lower price retailers not only enjoy higher revenue productivities and market shares, but they also have lower labor share. Extending the framework in Chapter 2 to allow for capital accumulation, I show that the decline in labor income share can be caused by reallocation of market shares to high productivity ﬁrms as a result of technological adoptions that increase consumer search.

abstract: PhD


title: Creating a Competency Framework for Intersectoral Collaboration Between OTs and Teachers

contributor:
Krupa, Terry
Rehabilitation Science

rights: Attribution-NonCommercial-ShareAlike 3.0 United States

subject:
Collaboration
Occupational Therapy
Teacher
School-Based

abstract:
Current inclusive approaches to education create challenges for teachers, who must meet the educational needs of diverse students.  Occupational therapists (OTs) assist some of these students through the provision of school-based occupational therapy (SBOT).  Although competency frameworks exist for interprofessional collaboration (e.g., the National Interprofessional Competency Framework [Canadian Interprofessional Health Collaborative, 2010]), these frameworks conceptualize collaboration as existing across professions within the health care sector.  Despite the need for OTs and teachers to work together, there is no competency framework in the collaboration literature to guide the intersectoral collaboration that occurs between these two professions.
The objective of this study was to develop a competency framework for collaboration between OTs and teachers.  A scoping review (Arksey & O’Malley, 2005) of the literature on tensions in collaboration between OTs and teachers was conducted.  A total of 46 unique tensions were charted across 30 articles.  This was followed by interviews of OTs (n=5), teachers (n=5), and parents (n=3) with SBOT experience.  An inductive analysis of the data was performed to yield 68 themes across 15 superthemes.  Methodological triangulation of the data was preformed to create a conceptual framework of collaboration between these two professions.  Lastly, based on data from the scoping review and interviews, competency modelling techniques (Marrelli, Tondora, & Hoge, 2005) were used to create a competency framework.  A total of 28 competencies were developed across the attitudes, skills, knowledge, behaviours, and beliefs required for collaboration.
The competency framework developed in this study rectifies a shortcoming in the literature on collaboration.  This competency framework can inform learning opportunities for OTs and teachers and potentially improve collaboration between these two professions.

abstract: PhD


title: Robust Predictive Resource Allocation for Video Delivery Over Future Wireless Networks

contributor:
Hassanein, Hossam
Noureldin, Aboelmagd
Electrical and Computer Engineering

subject:
Stochastic Optimization
Video Streaming
Predictive Resource Allocation
Robust Optimization
Machine Learning

abstract: The promising energy saving and quality of service (QoS) gains of Predictive Resource Allocation (PRA) for video streaming have recently been recognized in the wireless network research community. The PRA relies on future channel conditions to strategically deliver the video content of the mobile users. For instance, the whole video is pushed to the users moving towards the cell edge while prebuffering is postponed for others heading to the cell center in order to minimize the transmission energy. The focus of this thesis is to present a Robust Predictive Resource Allocation (R-PRA) framework to tackle practical uncertainties in the predicted information. In essence, the R-PRA adopts stochastic optimization techniques such as chance-constrained and recourse programming to model the uncertainties in the problem constraints and objectives. Although deterministic convex approximations are feasible, guided heuristic algorithms are introduced to provide real-time allocation. Moreover, Bayesian filtering methods (e.g. Kalman Filter) are adopted to continuously learn the degree of uncertainty which decreases the cost of robustness and maintains the prediction gains. Different variants for the robust framework are proposed such as energy-minimization and predictive adaptive streaming under erroneous prediction of channel rate, user demand and network resources. The variants unleash various design challenges for the network operators such as the trade-off between the complexity of uncertainty modelling and the prediction gains. All the variants are evaluated using a standard compliant simulation environment that comprises a network simulator 3 (ns-3) integrated with commercial solvers to obtain benchmark solutions. The results demonstrated the ability of R-PRA to meet the QoS level while maintaining the prediction gains over the opportunistic schemes employed in current networks. We believe that this framework set the groundwork for future robust predictive content delivery in which time horizon decisions are taken under practical uncertainties.

abstract: PhD


title: Distances Between Languages: Algorithms and Descriptional Complexity

contributor:
Salomaa, Kai
Rappaport, David
Computing

subject:
Regular Languages
Automata Theory
Formal Languages
Descriptional Complexity

abstract:
We consider the descriptional complexity of neighbourhoods of regular languages and the computational complexity of computing the distance between languages. Distance measures are defined on words to describe their similarity. These measures can be extended to languages, which are sets of words. We consider several different notions of distance measures on languages.

The neighbourhood of a language L is the set of words within some fixed distance of a word in L. We show that we can construct weighted finite automata for neighbourhoods of regular languages with respect to additive quasi-distances. We consider the state complexity of the neighbourhoods and the state complexity of approximate pattern matching. We establish a tight state complexity lower bound for the edit distance neighbourhood of a language recognized by a deterministic finite automaton.

We consider the deterministic and nondeterministic state complexity of prefix, suffix, and subword distance neighbourhoods. We establish tight deterministic state complexity bounds for the prefix and suffix distance neighbourhoods of regular languages and of finite languages. For prefix distance neighbourhoods, we consider prefix-convex subclasses of regular languages. We also establish the state complexity of suffix neighbourhoods of suffix-closed languages. We give an upper bound for the state complexity of the subword distance neighbourhood of a regular language.

Based on the edit distance algorithms of Mohri and Han and co-authors, we give algorithms for computing the prefix distance between two regular languages, a context-free language and a regular language, and two visibly pushdown languages. We extend these algorithms to compute the inner prefix distance of regular languages and visibly pushdown languages.

We give algorithms to compute the relative prefix distance of two regular languages. For a given integer k, we show that for a deterministic context-free language and a regular language or for two visibly pushdown languages, it is decidable whether their relative prefix distance is at most k. This is very close to the borderline between decidable and undecidable since, on the other hand, we show that deciding the same question for a deterministic context-free language and a visibly pushdown language is undecidable.

abstract: PhD


title: (Un)disciplined Performativity: Anonymity, Identity, and Governmentality on Yik Yak

contributor:
Murakami Wood, David
Sociology

subject:
Anonymity
Governmentality
Identity
Social Media
Sociology
Surveillance

abstract: Anonymous social media platforms, like Yik Yak, have been at the center of public controversies surrounding the proliferation of trolling, bullying, and gendered and racialized violence. This has led to a renewed scholarly attention to forms of anonymity and pseudonymity deployed in cyber-spaces that allow users to post content without attachment to their identity. This project has employed the use of qualitative and ethnographic methods to develop a case-study to explore two layers of empirical analysis: (1) as an empirical extension of post-structuralist theory, this project demonstrates how social actors engage in (un)disciplined performativity that allow users to share user-generated content as identity performance separated from their overall reputation and (2) explore how (un)disciplined users are regulated through various forms of vernacular and institutional governmentalities. In combining these two layers, I seek to understand how anonymity is performed, how anonymous regimes stabilize, re-stabilize, and through controversy, destabilize, and theorize how this constellation of performative acts and regulatory features are embedded within a larger political economy of Yik Yak. Performative anonymity exists within a sprawling set of collectives defined by unwritten and (un)disciplined norms, values, and creative content which are all captured in a wider surveillant assemblage. The results of this case-study reveal that though anonymity and pseudonymity inevitably feature a proliferation of trolling and e-bile, it also hosts users who may engage in forms of entertainment, caretaking, and/or a flight from social stigmatization. This project positions itself to oppose the imposition of a “real name” web advocated by Facebook and Google, and to maintain more efficiently moderated anonymous spaces for those who need to escape exposure to the constant gaze of friends, family, and strangers.

abstract: M.A.


title: Cardiorespiratory Fitness Versus Physical Activity as Predictors of All-Cause Mortality in Men

contributor:
Ross, Robert
Kinesiology and Health Studies

subject:
Mortality
Physical Activity
Cardiorespiratory Fitness
Risk Factors
Epidemiology

abstract:
BACKGROUND: Physical activity (PA) is a behaviour, defined as any bodily movement that increases energy expenditure above resting levels, while cardiorespiratory fitness (CRF) is a physiologic trait that reflects the ability of the respiratory, circulatory, and musculoskeletal systems to deliver and utilize oxygen. Although both CRF and PA are inversely associated with mortality risk, whether they are associated independent of each other is unclear.

METHODS: CRF was assessed by a maximal exercise test and PA was measured by self-report in 8171 male veterans. The predictive power of CRF and PA, along with clinical variables, was assessed for all-cause mortality during a mean (±SD) follow-up period of 8.7 (4.4) years during which there were 1349 deaths.

RESULTS: CRF was associated with mortality after adjusting for traditional risk factors commonly measured in clinical practice, and remained a strong predictor of mortality after further adjusting for PA (hazard ratio [HR], 0.85; 95% confidence interval [CI], 0.83 –0.87). PA was a significant predictor of mortality after controlling for clinical variables, however the association was eliminated after further adjusting for CRF (HR, 0.98; 95% CI, 0.88 – 1.10). In CRF stratified analysis, being active (≥150 min/week) was not associated with mortality within the unfit or fit categories (p>0.4). However, in PA stratified analysis, subjects categorized as fit (≥7 METS) had a lower risk of mortality regardless of PA status (p<0.001).

CONCLUSION: In adult men, PA was associated with mortality above and beyond established risk factors, but not CRF. Conversely, CRF remained a strong predictor of mortality, independent of PA status and established risk factors.

abstract: M.Sc.


title: Character Theory and Artin L-functions

contributor:
Murty, M. Ram
Mathematics and Statistics

subject:
Artin L-functions
Artin's conjecture
Automorphic representations
Heilbronn characters
Langlands reciprocity conjecture

abstract: In the spirit of Artin, Brauer, and Heilbronn, we implement representation theory together with the Artin formalism to study L-functions in this thesis. One of the major themes is motivated by the work of Heilbronn and many others on classical Heilbronn characters. We define the arithmetic Heilbronn characters and apply them to study L-functions. In particular, we prove a theorem concerning the analytic ranks of elliptic curves as predicted by the Birch-Swinnerton-Dyer conjecture. In a different vein, we employ the theory of supercharacters introduced by Diaconis and Isaacs to derive a supercharacter-theoretic analogue of Heilbronn characters. Moreover, we generalise the effective Chebotarev density theorem due to M. R. Murty, V. K. Murty, and Saradha in the context of supercharacter theory. Lastly, we study the conjectures of Artin and Langlands via group theory and extend the previous work of Arthur and Clozel. For instance, we introduce the notion of near supersolvability and near nilpotency, and show that Artin's conjecture holds if $\Gal(K/k)$ is nearly supersolvable. As a consequence, the Artin conjecture is true for any solvable Frobenius Galois extension. Also, we derive the automorphy for every nearly nilpotent group. Furthermore, the Langlands reciprocity conjecture has been established for Galois extensions of number fields of either square-free degree or odd cube-free degree as well as all non-$A_5$ extensions of degree at most 100.

abstract: PhD


title: Causal Uncertainty and Social Rejection

contributor:
Jacobson, Jill
Psychology

subject:
Causal Uncertainty
Social Rejection

abstract: I conducted three studies to investigate the impact of causal uncertainty on people's reactions to social rejection using three different social rejection research paradigms. In Study 1, I used the future-life paradigm, where participants completed a personality test and then were provided with feedback that in the future either they likely will end up with few, if any, meaningful social relationships (exclusion), or they will have many such relationships (inclusion).  In Study 2, I used the autobiographical recall paradigm where participants recalled a time when either they were socially excluded or included. In Study 3, I used a group task wherein participants ostensibly exchange information about themselves with other people in their experimental session but later learn that none of the other participants wanted to work with them (exclusion) or that all of them did (inclusion). In each study, the dependent variables were basic need fulfillment and negative affect. Across all three studies, higher levels of causal uncertainty were associated with lower levels of both need fulfilment and mood, but the predicted interaction between causal uncertainty and the rejection manipulation was not significant.

abstract: M.Sc.


title: Thermal History of the Flinton Group, Mazinaw Terrane, Grenville Province, Ontario

contributor: Geological Sciences and Geological Engineering

subject:
Geochronology
40Ar/39Ar geochronology
Grenville Province
Mazinaw Terrane
Flinton Group

abstract:
The eastern section of the Flinton Group, from Cloyne to Clyde Forks, is a long, narrow NE-SW trending belt of metasedimentary rocks belonging to the Mazinaw Terrane of the Grenville Province. Metamorphic grade increases southwest to northeast across the Flinton Group from greenschist to amphibolite facies, with metamorphic isograds perpendicular to the strike of bedding. Rocks from various members within the Flinton Group contain abundant biotite and muscovite and very little evidence of alteration.
Detailed petrography, electron-microprobe analysis, and 40Ar/39Ar dating of biotite and muscovite were used to investigate the thermal history of the Flinton Group.  40Ar/39Ar ages were obtained on eleven muscovite/biotite pairs and two muscovites from pelitic schists, and on a muscovite/biotite pair from a pegmatite. Biotite ages show a broad variation across the Flinton Group. Biotite ages in the western half of the study area range from 979 ± 6 Ma to 939 ± 6 Ma with an average pooled age of ~953 Ma, while the ages from the eastern half are much younger, from 908 ± 7 Ma to 885 ± 6 Ma with an average pooled age of ~900 Ma – reflecting a ~50 Ma age difference. Muscovite ages across the Flinton Group are uniform (with one exception) and range from 909 ± 8 Ma to 880 ± 7 Ma (±2σ) with an average pooled age of ~899Ma.
The observed age jump appears to coincide with increasing metamorphic grade and a change in quartz microtextures from grain boundary area reduction in the west to grain boundary migration in the east, suggesting that the eastern Mazinaw Terrane was buried deeper than the west due to tilting of the Mazinaw Terrane and movement along the Robertson Lake Shear Zone.

abstract: M.Sc.


title: Global Fluctuations of Random Matrices and the Second-Order Cauchy Transform

contributor:
Mingo, James
Belinschi, Serban
Mathematics and Statistics

subject:
Random Matrix Theory
Second-Order Free Probability
Global Fluctuations
Central Limit Theorem
Block Gaussian Matrices
Second-Order Cauchy Transform

abstract:
In this thesis we study the global fluctuations of random matrices (i.e., the covariance of two traces) from a second-order free probability perspective, putting a particular emphasis on block Gaussian matrices. Our main contributions are threefold.

First, we provide a formula for the second-order Cauchy transform of block Gaussian matrices in terms of the corresponding (matrix-valued) Cauchy transform. In order to do this, we introduce a (matrix-valued) second-order conditional expectation, in the spirit of the conditional expectations in operator-valued free probability theory.

Second, we establish a criterion, based on the positivity of a cluster function, that guarantees the existence of a particular integral representation for the second-order Cauchy transform. This approach is based on some relations between the moments and fluctuation moments of a measure on the plane.

Finally, we prove that under some conditions the covariance of resolvents converges to the second-order Cauchy transform. In fact, these conditions also ensure the convergence of the covariance of analytic linear statistics to a certain contour integral depending on the second-order Cauchy transform. In this context, we make explicit the relation between the notion of second-order limit distribution and the asymptotic Gaussianity of continuously differentiable linear statistics.

abstract: PhD


title: Average Controllability of Random Heat Equations

contributor:
Gharesifard, Bahman
Mansouri, Abdol-Reza
Mathematics and Statistics

subject:
Control Systems
Partial Differential Equations
Average Controllability
Heat Equation

abstract: In this thesis, we introduce random differential equations in an abstract framework and study their well-posedness. We study average controllability properties of a random heat equation when the diffusivity is a random variable. We show that the solutions of such random heat equations are both null and approximately controllable in average from an arbitrary open set of the domain and in an arbitrarily small time, recovering the known result when the random diffusivity is uniformly or exponentially distributed.

abstract: M.A.Sc.


title: Radical Polymerization of Bio-Renewable Butyrolactone Monomers

contributor:
Hutchinson, Robin A.
Chemical Engineering

subject:
Bio-Renewable
Superabsorbent Hydrogels
Polymerization Kinetics

abstract:
In this study, a bio-derived monomer, -methyl--methylene--butyrolactone (MeMBL) was saponified with sodium hydroxide (NaOH) to make the water-soluble monomer sodium 4-hydroxy-4-methyl-2-methylene butanoate (SHMeMB), that was copolymerized via radical polymerization in aqueous solution with acrylamide (AM) and crosslinker to synthesize superabsorbent hydrogels. Absorbency of these hydrogels was shown to be much higher than sodium acrylate hydrogels, with mechanical properties varying with molar composition and crosslinking content. Reactivity ratio of SHMeMB:AM at 50C and 15 wt% were estimated using low conversion data (rSHMeMB=0.12 and rAM=1.10), and the integrated Mayo-Lewis equation (rSHMeMB=0.17 and rAM=0.95). However, in-situ NMR results showed that SHMeMB:AM copolymerizations proceed at a slower rate than of a similar system of AM copolymerized with sodium 4-hydroxy-2-methylene butanoate (SHMB), a similar monomer produced by ring-opening of -methylene--butyrolactone (MBL). Pulsed-laser polymerization coupled with size exclusion chromatography (PLP-SEC) studies were done for both systems at 60°C and 10 wt% monomer concentration. Homopolymerization kp values were estimated to be 25 and 165 L/mols for SHMeMB and SHMB, respectively, confirming that SHMeMB is less reactive than SHMB.
Further kinetic studies of SHMeMB:AM copolymerization and homopolymerization of SHMeMB were conducted at elevated temperatures. SHMeMB conversions achieved a limiting value which decreased at higher temperatures, suggesting that polymerization rate was limited by depropagation. Comonomer composition drift also increased with temperature, with more AM incorporated into the polymer while SHMeMB underwent depropagation. Homopolymerization of SHMeMB with added sodium chloride (NaCl) showed a decrease in polymerization rate explained by an increase in propagation rate coefficient (kp) but an even greater increase in termination rate coefficient (kt) as supported by parameter estimation done using PREDICI. Even with added salt, however, depropagation was the dominant mechanism at higher temperatures. Lastly, the kinetic parameters estimated were implemented in a copolymerization model used to estimate the variation of kt with composition in SHMeMB:AM copolymerizations. It was found that the overall termination rate coefficient was dominated by the presence of SHMeMB, with as the estimate for kt,SHMeMB of the same order of magnitude as kt of another ionized water-soluble monomer, sodium methacrylic acid.

abstract: M.A.Sc.


title: Context Sensitive and Secure Parser Generation for Deep Packet Inspection of Binary Protocols

contributor:
Dean, Thomas
Computing

subject:
Binary
Network Protocol Parser
Parser
Context Sensitive
Computer
Security
Packet
Packet Verification
Traffic Analysis
Protocol Parsing
Networking
Network Security

abstract: Network protocol parsers constantly dissect a large number of network data to place into internal data structures for further processing by traffic analysis systems. Many network protocol parsers are hand-written for performance reasons, and lack the security required to run on mission-critical networks. We propose an approach that automatically generates custom protocol parsers to process network traffic to be used as part of an Intrusion Detection System. The user is provided a specification language in which they can define the protocols they need to analyse. This thesis looks at command and control/industrial control networks that are characterized by a limited number of known protocols. We present a robust, secure, and high-performing solution that deals with the issues that have only partially been addressed in this domain.

abstract: M.Sc.


title: Controllability of Underactuated Coupled Parabolic Systems

subject:
Applied Mathematics
Control Theory
Partial Differential Equations
Underactuated Systems
Coupled Systems

abstract: This thesis studies the null controllability of a system of coupled parabolic PDEs. Moreover, our work specializes to an important subclass of these control problems, where systems are underactuated and are coupled by first and zero-order couplings. We pose our control problem in a fairly new framework which divides the problem into interconnected parts: we refer to the first part as the analytic control problem, where we use slightly non-classical techniques to prove null controllability by means of internal controls appearing on every equation; we refer to the second part as the algebraic control problem, where we use an algebraic method to invert a linear partial differential operator that describes our system, which allows us to recover null controllability by means of internal controls which appear on only a few of the equations. By solving these control problems concurrently, we resolve the original problem (after some technical verifications on the regularity of the controls in the analytic system).

abstract: M.A.Sc.


title: Push-sum Algorithm on Time-varying Random Graphs

contributor:
Gharesifard, Bahman
Linder, Tamas
Mathematics and Statistics

subject:
Distributed Optimization
Communication Networks
Network Analysis and Control
Optimization algorithms
Cooperative control

abstract: In this thesis, we study the problem of achieving average consensus over a random time-varying sequence of directed graphs by extending the class of so-called push- sum algorithms to such random scenarios. Provided that an ergodicity notion, which we term the directed infinite flow property, holds and the auxiliary states of nodes are uniformly bounded away from zero infinitely often, we prove the almost sure convergence of the evolutions of this class of algorithms to the average of initial states. Moreover, for a random sequence of graphs generated using a time-varying B-irreducible sequence of probability matrices, we establish convergence rates for the proposed push-sum algorithm.

abstract: M.Sc.


title: The PICO-2L program: Towards Background-Free Dark Matter Direct Detection Using Bubble Chambers

contributor: Physics, Engineering Physics and Astronomy

subject:
PICO
PICO-2L
Dark Matter
Direct Detection
Bubble Chamber
WIMP
SNOLAB
C. Amole
Amole

abstract: The PICO-2L program commenced in 2013 with the deployment of a 2 litre bubble chamber filled with superheated C3F8 and over the next three years, conducted two separate WIMP-search experiments. The first run was conducted at 4 different energy thresholds ranging from 3.2 keV to 8.1 keV and a total of 12 candidate events were observed during a total exposure of 211.5 kg-days. Due to the non-uniform time distribution of the candidate events, no evidence for a WIMP-signal was claimed and upper limits on WIMP-nucleon scattering cross-sections were reported. These results represented the world leading limits at the time on spin-dependant WIMP- proton cross-sections with a 90% confidence upper limit of σ < 9.7 × 10^−40 cm^2 for a 30 GeV/c^2 WIMP. PICO-2L was redeployed in 2015 with modifications that aimed to control particulate contamination in the superheated fluid, and a follow- up WIMP-search experiment was conducted. During 129 kg-day exposure with the detector operating at an energy threshold of 3.3 keV, only 1 candidate event was observed, consistent with the predicted background rate from neutrons. These data showed that the measures taken to control the particulate contamination resulted in the eradication of the previously observed anomalous background events and provided the most stringent limits on WIMP-proton spin-dependent cross-sections with a 90% confidence upper limit of σ < 5.9 × 10^−40 cm2 for a 30 GeV/c^2 WIMP.

abstract: PhD


title: “A New Way Forward”: Reconciliation through Indigenous Social Innovation

contributor:
Rosenberg, Mark
Geography and Planning

subject:
Indigenous Peoples
Entrepreneurship
Social Innovation
Reconciliation

abstract:
In 2015, the Truth and Reconciliation Commission (TRC) of Canada released 94 Calls to Action including ‘Business and Reconciliation’ (Recommendation #92, TRC, 2015). The recommendation focuses mainly on the role of non-Indigenous Canadians. I argue that reconciliation is a two-way process and the role of Indigenous peoples in reconciliation has been largely overlooked. Thus, this research aims to take an Indigenous perspective on reconciliation, including the role that social innovation and Indigenous entrepreneurship can play in reconciliation processes in Canada.

This research employs a qualitative approach to data collection, including storytelling, narrative analysis and comparative methods. Concepts of reconciliation from an Indigenous entrepreneurial perspective, including personal definitions of reconciliation and social innovation, and how Indigenous businesses contribute to reconciliation processes are analysed. The results indicate that Indigenous entrepreneurs are actively contributing to reconciliation processes including playing a role in cultural awareness building through their goods and services. The research also indicates that the term ‘reconciliation’ takes on various meanings and is tied to life experiences, cultural relations, and community histories and dynamics. The results contribute an ‘Indigenous voice’ to current scholarship on reconciliation and might aid in the development of policy on Indigenous entrepreneurship, social innovation and economic development.

abstract: M.A.


title: Assessment of a Novel Phosphate Binding Therapy in Experimental Adenine-Induced Chronic Kidney Disease

contributor:
Adams, Michael
Holden, Rachel
Biomedical and Molecular Sciences

subject:
Vascular Calcification
Chronic Kidney Disease
Phosphate Binder
Magnesium

abstract: Hyperphosphatemia is a hallmark of progression in chronic kidney disease (CKD) and has been linked to the development of vascular calcification (VC), which increases cardiovascular risk. Phosphate binders are prescribed to control hyperphosphatemia. Fermagate is a calcium-free, magnesium-releasing, phosphate binder. Oral delivery of magnesium has been shown to attenuate VC. The aim of this study was to determine whether fermagate treatment compared to no treatment could impact VC in male Sprague-Dawley rats using an experimental model of adenine-induced CKD. The effect of fermagate on two different high phosphate dietary regimens was performed: high phosphate (0.75%) diet at all meals or a combination of low (0.5%) and high (1%) phosphate meals, such that the total amount of phosphate delivered was the same. In both studies, administration of fermagate increased serum magnesium and attenuated the levels of circulating phosphate, parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF-23). Compared to untreated CKD rats, fermagate treatment significantly reduced the prevalence of VC across a range of vascular tissues (70% VC in treated vs. 24% VC in untreated), but did not alter the accrual of magnesium in the vasculature. Serum phosphate and the prevalence of VC were higher in untreated and fermagate-treated rats on the constant high (0.75%) diet compared to the combination diet (0.5/1%), suggesting the impact of phosphate is dependent on the delivery of phosphate, not only the amount of phosphate consumed. Overall, the findings demonstrate that fermagate effectively reduces the bioavailability of the dietary phosphate load, increases systemic levels of magnesium, and limits the development and progression of CKD and VC.

abstract: M.Sc.