VictorJuiz/thesis huggingface dataset:
Weil Algebras and Double Lie Algebroids

Given a double vector bundle D -> M, we define a bigraded bundle of algebras W(D) -> M called the Weil algebra bundle of D. The space W(D) of sections of this algebra realizes the algebra of functions on the supermanifold D[1,1]. We describe in detail the relations between the Weil algebra bundles of D and those of the double vector bundles D', D'' obtained from D by duality operations. We show that VB algebroid structures on D are equivalent to horizontal or vertical differentials on two of the Weil algebras and a Gerstenhaber bracket on the third. Furthermore, Mackenzie's definition of a double Lie algebroid is equivalent to compatibilities between two such structures on any one of the three Weil algebras. In particular, we obtain a classical version of Voronov's result characterizing double Lie algebroid structures. In the case that D=TA is the tangent prolongation of a Lie algebroid, we find that W(D) is the Weil algebra of the Lie algebroid, as defined by Mehta and Abad-Crainic. We show that the deformation complex of Lie algebroids, the theory of IM forms and IM multivector fields, and 2-term representations up to homotopy all have natural interpretations in terms of our Weil algebras.

Keywords: algebra
differential geometry
Lie algebroid
Lie theory
Poisson geometry
Weil algebra
Advisor: Meinrenken, Eckhard
Development of Optical Zoom and Optical Image Stabilization Systems for Miniature Cameras

This thesis presents the development of an optical zooming (OZ) system and an optical image stabilization (OIS) system suitable for miniature cameras. Miniature cameras are employed in systems such as smartphones or endoscopic cameras where space is limited, and power requirements are strict due to the limited battery life. Therefore, compactness of the system is one of the main motivations in pursuing new designs of OZ and OIS systems. The OZ system presented in this thesis is capable of 2.06× magnification while the footprint area of the OZ system is 37% smaller than commercial counterparts. The roadmap to develop such a compact OZ system is explained in detail including presentation of simple optical designs along with all the analytical calculations and optical simulations. The feasibility of the OZ system is also discussed in terms of manufacturability using a tolerancing study. The OIS system proposed in this thesis aims to correct ±1° hand tremor yaw and pitch motions and hand tremor translation of 1.7 mm along the lateral directions of the image plane while offering a smaller footprint up to 28% than commercial counterparts. Mechanical design of all components is discussed within the scope of system-level design. Detailed analyses of the friction, damping and adhesion issues are investigated, and finite element modelling simulations are conducted in the design step of the OIS system. The fabrication process flow for the MEMS electrostatic actuators is also presented. Prototype fabrication has been successfully realized in order to confirm the disclosed design is promising to realize OIS. The prototype MEMS actuator shows 6 μm stroke at 50 Volts while it maintains a planar motion with maximum non-planarity of 0.012° throughout the travel range. All in all, the designed OIS system offers a compact yet effective image stabilization system suitable for miniature cameras.

Keywords: MEMS
Microactuator
Miniature Camera
Optical Image Stabilization
Optical Zoom
Optomechanical Design
Advisor: Ben Mrad, Ridha
Strong Chemical Tagging in the Milky Way

Comprehending the evolutionary history of the Milky Way can offer great insight into how both our home Galaxy and others form and grow. However, studying the Milky Way from our position embedded within it is difficult, and this challenge is exacerbated by the fact that our observations of our Galaxy are limited to a snapshot of its current behaviour. Understanding how the Milky Way has evolved over its approximately 13 billion year lifetime requires unique ways of leveraging astrophysical measurements to constrain the Galaxy's history. This study of the Milky Way's present-day properties to reveal its prior evolution is broadly known as Galactic archaeology. The stars of the Milky Way are particularly promising targets for Galactic archaeology, as judicious observations can constrain a wide array of stellar properties. However, using these properties to uncover individual stellar histories can be challenging. A star's photometric signature changes as it ages, and its gravitational interactions with other components of the Galaxy modify its kinematics, erasing most of the evidence of its past motion through the Milky Way. Fortunately, while these other properties change, a star's atmosphere carries for its entire life an imprint of the elemental abundances of the gas from which it formed. Grouping stars based on this chemical information is called chemical tagging, and this technique can identify groups of stars born in the same giant molecular cloud ('birth clusters') through their shared chemical signatures. In this thesis work, I describe my work on chemical tagging, culminating in the first fully blind chemical tagging experiment with a physically motivated clustering algorithm. The birth cluster candidates identified through this process offer a unique avenue of study, constraining not just individual stellar ages, but the star formation and chemical enrichment history of the Milky Way. Chemical tagging thus enables the detailed analysis of previously inaccessible parts of the Galaxy's history, and the application of the technique will radically alter our understanding of the evolution of the Milky Way.

Keywords: Chemical Tagging
Clustering
Dimensionality Reduction
Milky Way
Stars
Stellar Chemistry
Advisor: Bovy, Jo
Indigenous Girlhood: Narratives of Colonial Care in Law and Literature

As Canada assumes legal responsibility over an unprecedented number of Indigenous girls entering carceral facilities, educational boarding arrangements, and foster care, it is important to examine how the state is implicated in harming these girls. While these institutions ostensibly exist to provide Indigenous girls with care, they actually place Indigenous girls at greater risk of violence, disappearance, and death. Rather than focus on children or women more broadly, this dissertation considers how Indigenous girls' unique social location and legal minor status subjects these girls to greater state surveillance and management. What’s more, this analysis establishes connections between state violence against Indigenous girls and Canada’s settler colonial regime. This dissertation is organized into two parts. In part one, I examine the production of colonial narratives about violence against Indigenous girls through the Inquiry into the Circumstances Surrounding the Death of Phoenix Sinclair (2013) and the Inquest into the Deaths of Seven First Nations Youth (2016). In part two, I shift my attention toward Indigenous feminist literature on Indigenous girlhood. Through a close reading of Tracey Lindberg’s Birdie (2015) and The Break (2016) by Katherena Vermette, this study considers the theoretical and methodological possibilities of Indigenous feminist storytelling. Through an extensive examination of legal processes and Indigenous feminist literature, this dissertation offers innovative theoretical and methodological tools for addressing settler colonialism and other structures of oppression targeting Indigenous girls, as well as paths forward.

Keywords: Child Welfare
Education
Indigenous
Indigenous Feminism
Indigenous girls
Settler Colonialism
Advisor: Tuck, Eve
Mobilization of Platinum, Palladium and Gold by Magmatic Brines: An Experimental Study

Magmatic ore deposits enriched in platinum-group elements (PGE) often show evidence of previous hydrothermal activity. However, the exact role of hydrothermal processes in PGE ore formation has been uncertain due, in part, to a lack of systematic experimental data on the solubility and speciation of the PGE in hydrothermal fluids. To fill this knowledge gap, this thesis presents results using the synthetic fluid inclusion method to determine the solubility and speciation of Pt, Pd and Au in Cl-bearing aqueous fluids at conditions relevant to the emplacement of magmas in the crustal environment. The data presented here show that high temperature aqueous brines can transport well above 1 μg/g Pt, Pd and Au, as determined by fluid concentrations at metal saturation. Platinum and Pd are predicted to be in the 2+ oxidation state, whereas Au is predicted to be in the 1+ oxidation state in the fluids investigated. The solubilities of Pt, Pd and Au show a positive correlation with oxygen fugacity (ƒO2), temperature (T), fluid acidity (pH) and total chloride concentration (Cltotal). Trends in solubility with pH and total chlorinity indicate that Pt, Pd and Au are transported as chloride complexes. Results from thermodynamic modeling suggest that Pt and Pd are primarily transported as PtCl3– and PdCl3–, with minor contributions from PtCl2 and PdCl2, in high-temperature aqueous brines. Thermodynamic modeling predictions regarding the complexing species of Au are less certain, although HAuCl2 is expected to be important at high chloride concentrations and at low pH, with AuCl predominant at low chloride concentrations and at high pH. The relatively high metal solubilities determined in this work indicate hydrothermal fluids may be important in the processes that govern the formation of PGE enriched ore deposits. Additional work was done to apply the fluid-trap method with a modified cryogenic cell to obtain accurate metal solubilities at the sub-μg/g level. Despite several advancements being made in the method development, metal-fluid equilibrium could not be demonstrated in the experimental runs. Therefore, additional work is required to validate the fluid-trap method as a reliable technique to measure precious metal solubilities in upper crustal environments.

Keywords: Brine
Gold
Hydrothermal
Magmatic
Palladium
Platinum
Advisor: Brenan, James M
Zajacz, Zoltán
The Underestimated Role of Temperate Wetlands in the Late Quaternary Terrestrial Carbon Cycle

Organic matter stored in wetlands constitutes a globally significant terrestrial carbon pool interacting with atmospheric carbon via unique ecological processes that release CH4 but take in CO2. Efforts are ongoing to quantify the role of wetlands in terrestrial-atmosphere carbon exchanges, but observational data are unavoidably limited. Wetland drainage and losses have been profound in many countries, particularly in temperate latitudes; these losses took place prior to any eld measurements of carbon stocks or fluxes. Temperate wetlands have often been assumed to accumulate little to no peat, and thus, have had minimal importance in wetland carbon inventories. This thesis aims to point out the underestimated role that the temperate wetlands have played in the terrestrial carbon cycle, by conducting three case studies during the Anthropocene, the Holocene, and the late glacial period. First, the distribution of pre-settlement wetlands in southern Ontario was reconstructed using geospatial map overlays—the locations, peat depths and carbon densities from extant wetlands were used to assign pre-settlement wetlands to wetland types (bog, fen, swamp or marsh). More than half of the pre-settlement wetlands disappeared with potential carbon release up to 2 Pg since the early 19th century. Second, southern Ontario's largest swamp was investigated for paleoecological history using peat coring and pollen counting. This analysis indicated that the swamp established by about 8000 years ago, perhaps in response to the intensification of lake-effect snow, and it has accumulated thick organic-rich deposits since that time. Third, a model-simulated peatland expansion in the American Midwest was linked spatially to the distribution of enigmatic "no-analog" pollen assemblages during the last deglaciation. Estimates of early settlement era forest composition were used in conjunction with wetland simulations and machine learning algorithms to reconstruct natural wet forests in the deglacial landscape. These results show that wetland extent exceeded that of uplands, and this explains the key components of the no-analog pollen assemblages. During the Bølling-Allerød period, rivers transporting ice-sheet meltwater may have increased wetland cover across the region, causing the unprecedented dominance of wet forests, which potentially contributed to the northern hemispheric CH4 source enhancement.

Keywords: carbon
Great Lakes
peat
pollen
swamp
wetland
Advisor: Finkelstein, Sarah A
Cowling, Sharon A
Understanding (De)alienation in Social Movements: Resident Activism and Anti-poverty Organizing in the Toronto-area

This study revisits Marx’s theory of alienation, primarily through a sociological and adult learning theory lens, emphasizing how collective activity is a means to overcome structural and systemic forms of alienation. This study is theoretically-driven and makes use of empirical materials to examine the forms and dynamics present in social movement activity as they relate to overcoming alienating conditions. The empirical observations uncover how an analysis of social movement activities through a lens of learning de/alienation allows for a unique contribution to the literature on social movement learning. In exploring motivational dimensions of social movement activity, this study demonstrates how a conceptual framework centred on recovering Marx’s theory of alienation can contribute a unique understanding of the learning processes in social movement activities. In exploring indicative narratives from a case in the Toronto-area, this dissertation examines; 1) how learning de/alienation can be identified as motivation for activist engagement, and 2) the role of movement organizations in facilitating learning de/alienation. The operationalization of Marx’s theory of alienation is furthered by integrating key concepts from Bourdieu’s theory of practice as well as Cultural Historical Activity Theory (CHAT) in order to emphasize a dialectic approach to examining the forms of learning and activity that take place in the sites examined. The indicative narratives selected for both analytic chapters are presented to demonstrate how a recovery of Marx’s theory of alienation can prove fruitful in understanding the underlying dynamics of movement participation as well as the opportunities for emphasizing use-value mediated activities that relate to broader struggles for critical social change. The contributions of this dissertation are three-fold in its examination of movement activity and activist learning; 1) a recovery of traditional conceptual ideas surrounding human de/alienation in dialogue with the literature in social movement learning, 2) an examination of how habitus mediates learning de/alienation in community activism with particular attention to Marxist CHAT concepts as a multi-dimensional approach, and 3) an empirical demonstration that dialogues with first two areas in order to better understand opportunities for identifying activist learning and engagement for critical social change.

Keywords: everyday activism
social movement learning
sociocultural learning theory
theory of alienation
Advisor: Sawchuk, Peter H
Mobile Mixed Reality Technologies for Language Teaching and Learning

Mobile learning technologies have become ubiquitous, accessible tools for many teachers and learners in higher education contexts across the globe; however, the uptake of emerging, innovative mobile applications is not always reflected in their implementation in language learning classrooms. Mixed Reality (MR) applications, which include both Augmented Reality (AR) and Virtual Reality (VR) represent examples of such largely unexplored, state-of the art, immersive technologies in language education. Recent literature suggests the use of MR technologies can offer benefits to language learners in enhancing vocabulary development (Godwin-Jones, 2016; Liu Tsai, 2013), motivation and engagement (Ibáñez, Kloos, Leony, Rueda, Maroto, 2011; Liu, Tan, Chu, 2010; Dunleavy Dede, 2014) and collaborative, multimodal meaning-making (Ho, Nelson, Müeller-Wittig, 2011). Despite these advantages, there has been limited empirically-based research which explores specific benefits and affordances in language learning. Research revealing the advantages of AR and VR exists, however, in other educational settings, including: Humanities, Arts, Social Sciences, Business, Law, Science, Engineering and Health (Lok et al., 2006; Bacca, Baldiris, Fabregat, Graf, 2014; Marcel, 2019). Through the implementation of VR in a quasi-experimental, mixed-methods research study in a college in Canada, with teachers and learners in a multi-level English for Academic Preparation (EAP) program, this study explores benefits, challenges and affordances of MR technologies within a Canadian higher education context. The analysis of data from EAP students (N = 95) and instructors (N = 6) includes vocabulary assessments, surveys, Nearpod data, VoiceThread reflections, interviews, and classroom observations. Results reveal trends in learning gains by the experimental groups in vocabulary scores and a number of benefits and affordances of the VR technology implementation reported by both students and instructors. While the main goal of this research was to explore how mobile MR applications could be used in language learning contexts in higher education to improve learning outcomes through experiential learning activities with these innovative technologies, it is hoped that this research will also serve to inform practice for educators in their selection and use of educational learning technologies and contribute to the growing body of knowledge and research in this field.

Keywords: Education
Experiential learning
Language
Mixed Reality
Virtual Reality
Vocabulary
Advisor: Piccardo, Enrica
Candidate Bivalent HCV Vaccine: A Novel Approach To Vaccine Design for Hyper-variable Viruses

One percent of the world’s population is chronically infected with the hepatitis C Virus (HCV), and it estimated nearly 500,000 HCV related deaths will occur in 2020. Despite remarkable progress in treatment, the high number of occult infections, risk of reinfection following treatment, and the nearly 2 million new cases annually underscores the urgent need for a prophylactic vaccine. Vaccine development has faltered because the extreme genetic diversity of the virus has precluded the induction of broadly protective antibodies (AB) with classical vaccines. Here, I describe a novel approach to vaccine design for antigenically variable pathogens based on transformation of genetic diversity into physicochemical variability, using HCV as a prototypical variable pathogen. Based on the hypothesis that polyvalent vaccination with antigenically variable immunogens will bias the immune response to recognize physicochemically conserved residues, our approach selects for multivalent constituents relationally defined by their physicochemical divergence. Though it has been proposed that highly variable, immunodominant epitopes should be amputated from HCV vaccine antigens to avoid induction of strain-specific antibodies, as a proof-of-concept our approach was used to develop a bivalent HCV vaccine explicitly designed to elicit AB to HVR1 (hypervariable region 1), the most variable epitope of any known human pathogen. Remarkably, the polyclonal response induced by vaccination was pan-genotypically neutralizing. These results support our hypothesis that physiochemically constrained signatures within hypervariable epitopes can be effectively targeted by vaccines designed using our novel approach.

Keywords: Hepatitis C Virus
HVR1
Neutralizing Antibody
Polyvalent immunogen
Vaccine
Variable pathogen
Advisor: AbouHaidar, Mounir
Feld, Jordan
Global Analyses of Synaptic Remodeling and Wiring Variability of the Developing C. elegans Brain

From birth to adulthood, an animal's nervous system changes to facilitate the maturation, refinement, and expansion of its behavioural repertoire. Studies at individual synapse level have resulted in an assortment of genetic and cellular factors that affect synapse remodeling. What needs to be addressed, however, is whether and how synaptic changes collectively affect the circuit-level maturation and reshaping. My Ph.D. work addresses this question in the C. elegans nervous system. Using serial section-electron microscopy, I mapped the wiring diagram of its brain, or connectome, from birth to adulthood, to examine how and why brain wiring changes with age. I present the wiring diagrams and topology structures reconstructed from eight isogenic wild-type C. elegans, from the first larva to adult stages. By comparing these datasets, I reveal that despite a small and invariant neuron number and isogeneity, a nematode's brain has a large capacity for structural plasticity. Remarkably, the most stable connectivity of the central nervous system is its centralized decision-making circuitry, whereas sensory and motor pathways undergo substantial remodeling. I also find that the synapse remodeling events collectively lead to refined modularity of sensory and motor circuits. The overall topology of the nervous system is largely preserved from birth to adult, establishing a scaffold upon which all developmental and variable synaptic connectivity is built. I analyze the relationship between topology changes, synapse remodeling events, and wiring maturation during development. Four rules correlate synapse remodeling events with the structural characteristics of the L1 brain. Using in silico simulation, I demonstrate that they are sufficient to evolve the adult connectome from that of the L1 larva. These studies demonstrate that brain-wide wiring plasticity is an inherent property of individuals of an isogenic population. The connectome is not a fixed entity, as often assumed, but can itself be a target of developmental programs and external cues. It is necessary to obtain individual-level wiring to interpret plasticity and behaviours. This study has laid the essential foundation to explore how genetic factors, environments, and experiences shape the developing brain.

Keywords: C. elegans
Connectomics
Development
Maturation
Advisor: Zhen, Mei