VictorJuiz/thesis huggingface dataset:
High-efficiency Waveguide Tunable Leaky-wave Antennas and Phase-shifters

In this thesis, we discuss several ways that one can increase the radiation efficiency of leaky-wave beam-steerable antennas. In this effort, both frequency and fixed frequency scanned leaky-wave antennas are considered. Specifically, we discuss the design and implementation of a slow-wave frequency-scanned leaky-wave antenna that can achieve a high radiation efficiency with a split-block structure. The concentration of the current distribution in the middle of the waveguide due to the proposed design results in reducing the Ohmic loss in the gap of the split-block antenna and maximizing its efficiency. The antenna has a much smaller width compared to its serpentine waveguide counterparts which makes it possible to place several of them side-by-side to narrow the beam or perform beam-steering in the non-scanning plane. We also study the design and implementation of a slotted waveguide with impedance walls as a fixed-frequency beam-steerable leaky-wave antenna. This antenna can be used when a high radiation efficiency is required for fixed-frequency beam steering at relatively high frequencies where the quality factor of electrical tunable elements decreases considerably. In the designed antenna, the power loss in the varactors on the tunable impedance walls is the least compared to the other loss mechanisms. This is because of locating the varactors where the electric field strength is reduced in the reconfigurable waveguide. Using the designed impedance surfaces with reduced power dissipation in varactors, we introduce a new tunable phase shifter based on surface waves with high efficiency. The proposed phase shifter can be used for the implementation of phased arrays with low loss at high frequencies. The design of the proposed phase-shifter is based on maximizing its figure-of-merit (FOM) for achieving 360\textsuperscript{o} of phase shift.

Keywords: Antennas
Leaky-waves
Metasurfaces
Advisor: Eleftheriades, George V
Random Canonical Products and the Secular Function of the Stochastic Airy Operator

Secular functions of random matrices and their limits are of recent interest in random matrix theory. Such functions are entire with zeros the spectra of the corresponding operators. For example, the general beta ensembles, extending the joint eigenvalue law of classical random matrix ensembles, have a universal soft edge limit upon rescaling called the Airy beta point process. This process also arises as eigenvalues of a random operator called the stochastic Airy operator. It is proven here that secular functions of the general beta ensembles converge in distribution to that of the stochastic Airy operator. Furthermore, this convergence is realized in the context of regularized determinants of operators. This is done by proving new asymptotics of the Airy process and rigidity estimates of the general beta ensembles and establishing this convergence for more general random sequences. These results extend the currently known case for the Gaussian ensembles in Lambert and Paquette (2020). Growth asymptotics are proven for the secular function of the stochastic Airy operator, and as an application some open questions in Lambert and Paquette (2020) are answered. By applying and extending the work in Valkó and Virág (2020) in the bulk case, the secular function is proven to be a unique limiting solution of an ordinary differential equation. Additionally, new convergence laws for discrete matrix models limiting to the stochastic Airy operator are proven, including convergence of the derivatives of eigenfunctions.

Keywords: airy
beta
ensemble
matrix
secular
stochastic
Advisor: Virág, Bálint BV
Controlling the Function of Nanomaterials using their Protein Coronas

Blood proteins adsorb onto the surface of nanomaterials after intravenous injection to form a protein corona. Controlling the function of nanomaterials with a protein corona remains challenging. That is because the protein corona can 1) mediate nanomaterial-cell interactions and even 2) block the function of targeting ligands conjugated on nanomaterials. In this thesis, I demonstrated that these two issues could be solved using the protein corona itself by first understanding its function, structure, and kinetics. I discovered that not all proteins in the protein corona are functional, and that proteins are structurally organized as assemblies. By manipulating the structure of the protein corona, I could alter its function and thus control nanoparticle interactions with macrophage cells. Using biolayer interferometry and molecular dynamics simulations, I identified that the protein corona reaches an equilibrium state where the size of the corona stops growing with minimal protein exchange. Conjugating targeting ligands on top of the equilibrated corona enables control over the targeting ability. Nanomaterials synthesized using this method can bind to target cells even in the presence of serum proteins. Overall, this thesis presented a fundamental understanding of the function, structure, and kinetics of the protein corona that inspired two novel methods of controlling the function of nanomaterials for biomedical applications.

Keywords: Immunoassay
Nanomaterials
Nanomedicine
Protein corona
Targeting ligands
Advisor: Chan, Warren
Dispossession and Resistance: A History of Indigenous and Settler Relations to Land in British Columbia, 1800-1890

Throughout Canada treaties between Indigenous peoples and the crown have provided the legal foundation for the crown’s underlying title to land. In British Columbia, however, only a handful of treaties were made. Nevertheless today, according to one now contested view of Canadian common law, the crown holds underlying title to all lands in the province, much of which, is held in fee simple by non-Indigenous people. How did the crown acquire underlying title to all the land in British Columbia? What were the legal mechanisms that erased Indigenous land rights and placed the land in the hands non-Indigenous people? How did Indigenous communities manifest resistance to the curtailment of their land rights? This thesis explores these questions and argues that Indigenous land was converted into crown land and placed in the hands of white settlers through proclamations, land registry acts, and government policy.

Keywords: British Columbia
History
Indigenous Peoples
Law
Property
Property Law
Advisor: Phillips, Jim
The Politics of Homelessness: Poverty, Policy, and Political Participation

How do everyday interactions with the welfare state influence political participation? The policies individuals interact with dictate their relationship with the state. Policy designs, therefore, play a vital role in the inclusion of individuals into the welfare state as well as the political system. Policies have effects on how individuals participate politically, through the resources they distribute, the institutional arrangements they govern, and the messages they send regarding the deservingness of target populations (Pierson, 1993; Campbell, 2004; Schneider & Ingram, 1993; Mettler, 2005). How policy designs influence participation, and how different policies integrate to influence political participation and inclusion, requires further attention. An investigation of the relationship between policy and participation from the perspective of a marginalized population allows for a bottom-up examination of the welfare state (Michener, SoRelle & Thurston, 2020). Individuals experiencing homelessness are among the most vulnerable in western states and interact with several state appendages and services. In doing so, they advocate for themselves and others while interacting with multiple policies. In this dissertation, I describe a causal mechanism that connects the inclusivity of policy design and the interaction of multiple policies on the one hand, to political participation on the other. Policy inclusivity and participation are defined inductively. I present empirical evidence from a mixed method comparative study, which includes 118 interviews with individuals experiencing homelessness, service providers, and policymakers in Melbourne and Toronto. Both cities are located in liberal welfare states with means-tested and individualist policies to combat homelessness. Results from a quantitative analysis of national election surveys finds that there are complex relationships between policy, poverty, and participation. Qualitative interviews, therefore, add vital nuance to these quantitative findings and build the mechanism of policy design inclusivity. Even given failing and exclusionary housing, social assistance, and health policies, individuals experiencing homelessness participate and express their desire to bring about change. Investigating how and where individuals participate, as well as the policy designs that encourage or limit that participation, is therefore important to policy success and democratic inclusion. This research contributes to multiple bodies of political science and public policy literature.

Keywords: homelessness
policy feedback
political participation
public policy
Advisor: White, Linda A
To Do This Discussion Differently: Queering Teacher Professional Learning Through Comic Art and Graphic Stories

This dissertation describes a qualitative research study that is grounded in the experience of learning-while-teaching. My methodology includes contemplative teacher practice and arts-based data analysis, the demonstration of which incorporates my own experience as an elementary school teacher, a teacher educator, and a queer/trans (Q/T) person in schools. Overall, this research aims to consider how we might begin to address socially- and emotionally-challenging topics in teacher education differently. Specifically, I ask: What formats for teacher professional learning (TPL) show promise in supporting educators to expect, welcome, and include trans/gender diverse (GD) students, families and staff in schools? Through a theoretical lens that brings together perspectives from practitioner research, critical ethnography and arts-based data analysis, I work to centre the voices and experiences of trans/GD people involved in the school system in various roles. As an important boundary to that idea of “centring”, I emphasize the need to shift the expectation that it is Q/T people who will continue to do this teaching by offering our own bodies as exemplars, and to disrupt the notion that we must literally en-ACT these explanations in order to deserve and receive school communities that care for us. The literal content of this dissertation describes what the process of my research has taught me about my data, while its physical form works to enact that learning through the medium of comic art. I have communicated the findings of my research through a series of graphic stories, which also encourage the reader to consider what they read/see/feel in the context of their own lives and identities. These books both ask for and offer the kind of commitment to individual identity work that is frequently expected, yet rarely modeled or supported, in teacher education. This interweaving of process through product and the blurring of story-telling/receiving in academia is important because it proposes a less- binary future for education. This thesis and these stories imagine a system where teachers are taught to expect that we will learn and change continuously in relation to every experience, and every individual, who is part of our classroom community.

Keywords: Arts-Based Ethnography
Comic Art as Pedagogy
Contemplative Teacher Practice
Graphic Scholarship
Queer / Transgender / Gender Diverse (GD)
Teacher Professional Learning
Advisor: Goldstein, Tara
Applying Health Technology Assessment Methodologies to Support Health Policy for Lyme Disease: Assessing Health and Economic Burden, and Cost-effectiveness of Potential Interventions

Lyme disease (LD) is an increasingly common vector-borne disease reported in temperate climate zones in North America. In Canada, the number of confirmed LD cases reported has increased from 144 in 2009 to 2,851 in 2021. An increasing number of LD cases along with the controversies on clinical management within the medical community and patient advocacy groups prompted the government to commit to addressing the challenges of recognition, timely diagnosis, and treatment of LD, mandated by the Federal Framework on Lyme Disease Act. However, evidence gaps related to LD health outcomes, the economic burden to the healthcare system, and cost-effectiveness of LD interventions remained. In the last decade, high-quality evidence has been more commonly produced by health technology assessment (HTA) methodologies for infectious diseases to support public health planning and the evaluation of innovative technologies. Therefore, the goal of this thesis was to use specific HTA methodologies to generate evidence to inform health policy for LD in Ontario. The first study conducted was a systematic review of long-term sequelae, prognostic factors, health-related quality of life, and health state utility values associated with LD in North America and Europe. The second study estimated the economic burden and health outcomes attributable to laboratory-confirmed LD in Ontario using a population-based retrospective cohort study, health administrative data and laboratory test data. The third study involved the development of a microsimulation model to simulate the natural disease history of LD and estimate the number of LD cases, sequelae, and projected population burden, expressed as quality-adjusted life years (QALYs). The fourth study used the microsimulation model to conduct a cost-utility analysis of potential risk-based LD vaccination programs in Ontario assuming a vaccine candidate profile. This thesis summarized long-term outcomes associated with LD, which can be used to shape or support clinical management guidelines, and future cohort studies. While investing in universal vaccination programs are typically good value, a tailored approach may be optimal for LD. This body of work demonstrated how HTA methodologies can be used to synthesize clinical, epidemiological, and economic evidence to support current and future health policy decision-making for emerging infectious diseases.

Keywords: borrelia burgdorferi
economic evaluation
health services research
health technology assessment
lyme disease
Advisor: Sander, Beate
Exploring Post-secondary Instructors’ Approaches to Teaching Introductory Statistics Courses Online

This study employs a multiple case study approach to investigate teaching approaches used by post-secondary instructors in undergraduate online introductory statistics courses. This study draws on semi-structured interviews and document analysis to explore how instructors synthesize their use of technological, pedagogical, and content knowledge (TPACK) in virtual settings. The results from this study indicate that teaching introductory statistics courses online offer many benefits to both students and instructors. They provide continuous access to content, flexibility, and autonomy with regard to learning. Challenges with teaching introductory statistics online include learner-instructor interactions, academic integrity, and course offering properties (e.g., grading support, class size). The four major findings from the case study with these instructors include: 1) online environments provide ways for instructors to give students agency over when, where, and how they access and engage with statistics content; 2) tools should be used that allow instructors and students to write and present statistics syntax; 3) academic integrity and large class sizes pose challenges to teaching introductory statistics online; and 4) informal and formal professional development settings are necessary for successfully facilitating an introductory statistics online. Implications of this study suggest that successfully teaching undergraduate introductory statistics courses online require joint efforts on behalf of instructors, administrators, support units, and educational software developers.

Advisor: McDougall, Doug
Secretagogin is Essential for Circadian GLP-1 Secretion and is Altered in a Model of Type 2 Diabetes

Glucagon-like Peptide-1 (GLP-1) is secreted from intestinal L-cells in response to food intake to upregulate glucose-dependent insulin secretion. GLP-1 based therapies are therefore employed in the treatment of type 2 diabetes (T2D) through the use of receptor agonists or degradation inhibitors, which drastically increase levels in the circulation. Importantly, in physiology, GLP-1 exhibits a circadian pattern in its secretion, coordinating diurnal insulin secretion. Previous publications have shown that GLP-1 secretion closely follows Arntl expression in mGLUTag L-cells; however, intermediaries connecting the circadian clock to GLP-1 secretion remain to be elucidated. Interestingly, a mass spectrometry analysis in mGLUTag L-cells identified Secretagogin (SCGN) as highly upregulated at the peak GLP-1 secretion time point. SCGN is also rhythmic in pancreatic ɑ and ß–cells and is both essential for insulin secretion and reduced in islets from patients with T2D. Furthermore, a recent publication showed SCGN administration improves glucose tolerance in obese mice. I therefore hypothesized that SCGN is essential for circadian GLP-1 secretion and is reduced in a model of T2D. Analysis of synchronized mGLUTag and hNCI-h716 L-cells revealed circadian rhythms in Scgn RNA and protein, and BMAL1 demonstrated increased binding to the Scgn promoter at the peak time point of GLP-1 secretion. Immunostaining of murine and human ileum showed that all GLP-1+ cells expressed SCGN. Immunocytochemistry further demonstrated the translocation of SCGN to the membrane upon stimulation, with increased binding to ß-actin at the peak time point suggesting that SCGN facilitates cytoskeletal transport of granules to the membrane. Further functional analyses by Scgn knockdown (si-RNA) and knockout (Constitutive, Gcg-creERT2/+;Scgn-floxed and Vil-creERT2/+;Scgn-floxed) revealed that Scgn loss-of-function resulted in impaired rhythmic GLP-1 secretion. RNA-Seq analysis in Scgn knockdown mGLUTag L-cells demonstrated a decrease in pathways relating to ‘vesicle transport’. Lastly, in the high fat-streptozotocin model of T2D GLP-1 secretion was drastically elevated and arrhythmic in association with a similar shift and unexpected increase in the pattern of SCGN expression. Together, these findings show that L-cell Scgn is essential for circadian GLP-1 secretion in physiology and is increased in a model of T2D, with further studies warranted to investigate the mechanistic secretory alterations caused by Scgn loss-of-function.

Keywords: Circadian
GLP-1
Secretagogin
Secretion
Advisor: Brubaker, Patricia L
Special Correspondences of Abelian Varieties and Eisenstein series

Gross and Zagier were able to prove a relation between special values of derivatives of L-functions and algebro-geometrical data such as Heegner points and intersection numbers. A program initiated by Kudla generalized this to higher-dimensional cases and this has been a fruitful program of research for years. Here we prove two results in this direction. First, we consider the Shimura variety parametrizing pairs of CM abelian varieties of the same dimension with the same CM-field $K$ acting on them and define special cycles on this variety (over the integral model considered as a Deligne-Mumford stack) and relate the Arakelov degree of these special cycles to Fourier coefficients of totally positive index of Hilbert Eisenstein series. Then, we define Green functions on this Shimura variety and relate the degrees of Green functions to the Fourier coefficients of the same Eisenstein series with indices that are not totally positive (or the constant coefficient). In our second result, we do the same for the moduli space of pairs of abelian varieties first of which have CM by ring of integers $O_{K_0}$ of a CM-field $K_0$ and the second one is higher-dimensional and has an action by $O_{K_0}$. Then we use the same methods as in the first result to prove that the degrees of special cycles on this Shimura variety is related to Fourier coefficients of Eisenstein series.

Advisor: Kudla, Stephen
Blockade, Starvation, and Resistance: Gender, Violence, Trauma and Memory in the Nigerian Civil War, 1967-1970

The Nigerian civil war of 1967-1970 involved conflicts over ethnic differences, religious intolerance, political marginalization, and national insecurity. While these issues were local and internal, the conflict attracted intense interest from beyond Nigeria’s borders and sometimes humanitarian support to either of the belligerents: Nigeria and Biafra. Concentrating on the impact on women, this dissertation examines the 1966 attacks on easterners resident in northern cities, the consequences for displaced women and their children, and the subsequent wartime violence in the Biafran heartland. In analyzing the many ways in which the war shaped the everyday experiences of women, it also details their responses and actions. It argues that women’s traumatic experiences were the direct result of reckless actions on the part of the Nigerian government which imposed a blockade on Biafra, and the Biafran leadership which could have acted to alleviate the blockade but chose not to. This issue was “complex” and historians as well as locals have read it in different ways to apportion blame. By early 1968, the blockade and the shelling and bombing of Biafra by the Nigerian military had resulted in devastating food shortages and generated profound concern from the churches and humanitarian organizations. The International Committee of the Red Cross, along with the governments of the United States and Canada, arranged for corridors through which supplies would flow into the enclave. Although the Nigerian government reluctantly endorsed this arrangement, the Biafran government declined support for military reasons, thus exposing Biafra’s people to further misery. Nigerian forces’ bombing of markets where women operated also contributed to the acute shortages of food and other supplies in Biafra. Women in the Biafran heartland responded to the scourge of starvation by engaging in a transborder trade known as Afia Attack, a smuggling network controlled by women to facilitate the movement of food and medicine from Nigerian-controlled areas to Biafra. Women developed other survival strategies and practiced market rotation to ensure that trade continued. Despite their efforts to combat starvation and resist destruction, the humanitarian crisis in Biafra had devastating consequences for them and their children, killing at least one million people.

Keywords: Biafra
Conflict
Human Rights
Humanitarian Intervention
Nigerian Civil War
Starvation
Advisor: Musisi, Nakanyike B
Rockel, Stephen J