VictorJuiz/thesis huggingface dataset:
“It’s like there’s a string between us”: Transnationalism and the (Re)Creation of Home among Southern Sudanese Canadians
Keywords: Southern Sudanese refugees
Transnationalism

This dissertation is an exploration of the creative spaces often opened up by exile and forced migration, where Southern Sudanese negotiate and perform new forms of belonging and affiliation, while simultaneously (re)producing, ‘local’ practices in order to reaffirm and solidify existing relationships and identity categories. Through my examination of the creative spaces opened up by migration and exile, I also raise questions related to broader concerns in the field of forced migration and refugee studies regarding the need to problematize the often binary distinction between forced and voluntary migrants, which often places refugees in a category stripped of agency and choice. Based on 20 months of multi-sited field work in Calgary, Canada and Juba, South Sudan and exploring issues related community organization and shifting forms of affiliation, long distance nation building, transnational marriage and return migration, this dissertation demonstrates how settling-in and place-making involve both material and moral aspects of practice, and that refugees, regardless of the “forced” nature of their migration, are active agents in this process.
Spectral Methods in Extremal Combinatorics
Keywords: combinatorics

Extremal combinatorics studies how large a collection of objects can be if it satisfies a given set of restrictions. Inspired by a classical theorem due to Erdos, Ko and Rado, Simonovits and Sos posed the following problem: determine how large a collection of graphs on the vertex set {1,...,n} can be, if the intersection of any two of them contains a triangle. They conjectured that the largest possible collection, containing 1/8 of all graphs, consists of all graphs containing a fixed triangle (a triangle-star). The first major contribution of this thesis is a confirmation of this conjecture. We prove the Simonovits–Sos conjecture in the following strong form: the only triangle-intersecting families of measure at least 1/8 are triangle-stars (uniqueness), and every triangle-intersecting family of measure 1/8−e is O(e)-close to a triangle-star (stability). In order to prove the stability part of our theorem, we utilize a structure theorem for Boolean functions on {0,1}^m whose Fourier expansion is concentrated on the first t+1 levels, due to Kindler and Safra. The second major contribution of this thesis consists of two analogs of this theorem for Boolean functions on S_m whose Fourier expansion is concentrated on the first two levels. In the same way that the Kindler–Safra theorem is useful for studying triangle-intersecting families, our structure theorems are useful for studying intersecting families of permutations, which are families in which any two permutations agree on the image of at least one point. Using one of our theorems, we give a simple proof of the following result of Ellis, Friedgut and Pilpel: an intersecting family of permutations on S_m of size (1−e)(m−1)! is O(e)-close to a double coset, a family which consists of all permutations sending some point i to some point j.
Identification of Candidate Causal Variants and Estimation of Genetic Associations in GWAS and Post-GWAS Studies
Keywords: statistical genetics

Genome-wide association studies (GWAS) and next generation sequencing (NGS) studies are powerful high-throughput methods of scanning the human genome that have dramatically increased our ability to identify disease-causing genetic variants and estimate the magnitude of their effects. Leveraging the power of these technologies requires statistical methods tailored to the real world complexities of the data from these studies. Statistical methods developed during the era of small candidate gene studies fail to account for the extended scope of genome-wide studies, which encompasses: (1) discovery of disease-associated regions; (2) localization of associations to individual risk variants; and (3) estimation of effect size. In addition, high-throughput sequencing used for large samples differs from traditional Sanger sequencing in that genotyping error varies substantially over a region, which can distort evidence used to identify the disease-associated variant. In this thesis, I model these factors in order to increase accuracy of genetic effect estimation and accuracy of identification of disease-causing variants within disease-associated regions. I address these factors in three related settings: (1) GWAS study used alone to both discover and estimate the size of genetic effect at disease-associated variants; (2) GWAS study followed with sequencing to both discover an associated region via GWAS SNPs and estimate the size of genetic effect using the sequencing data; and (3) GWAS study with sequencing or imputation used jointly to identify candidate causal variants and estimate the corresponding effect sizes within an associated region. I develop novel statistical methods to address the specific localization and estimation problems encountered in each setting. Extensive simulation studies are used to explore the nature of these problems and to compare the performance of the new methods with the standard methods. Application to the Welcome Trust Case Control Consortium Type 1 Diabetes dataset and National Cancer Institute BPC3 aggressive prostate cancer study demonstrates the difference the methods make in the interpretation of evidence in these high-throughput studies.
Visual Attention among Patients with Schizophrenia: A Study of Visual Span and Selectivity in Visual Search
Keywords: Visual Selective Attention
Schizophrenia
Visual Search
Visual Span
Perceptual Span
Spotlight of Attention
Attentional Guidance
Motion Perception
Distractor Ratio
Symbol Digit Substitution
Cognitive Impairment

Attention is one of the most impaired cognitive functions in schizophrenia; however, the precise mechanisms underlying schizophrenia-related attention impairment are unclear. Progress in identifying these mechanisms has been hampered by using methods that are not designed to isolate specific cognitive processes. The purpose of the present dissertation was to investigate visual attention among patients with schizophrenia using the visual search paradigm — the dominant paradigm for studying attention in the cognitive sciences. Moreover, the current study used eye-tracking methodology to more finely examine the mechanisms underlying impaired visual search in this clinical population. This dissertation had three main objectives: (1) to investigate whether patients with schizophrenia have smaller and/or less dynamic visual spans, (2) to examine whether certain mechanisms guiding the visual selection of objects are impaired in schizophrenia, and (3) to determine the contribution of visual search performance to substitution test performance. Results indicated that patients’ visual spans are both smaller and less dynamic compared to healthy controls. On the other hand, selectivity for more informative distractors is intact in schizophrenia; however, impaired motion perception results in impaired target discrimination in the context of intact target selection. Results also indicated that visual search performance is a primary determinant of substitution test performance. Collectively, these data demonstrate, on one hand, an impairment among patients with schizophrenia in the distribution and flexible modulation of visual attention and, on the other hand, intact visual selective attention in the presence of strong bottom-up cues. The current data also demonstrate the important contribution of visual attention to a highly sensitive neuropsychological test and, by inference, to patients’ cognitive and real-world functioning.
Temporal Change in Crayfish Communities and Links to a Changing Environment
Keywords: crayfish ecology and conservation
environmental change
calcium declines
south-central Ontario

Community ecology and conservation are complementary disciplines under the umbrella of ecology, providing insight into the factors that determine where and how communities exist, and informing efforts aimed at sustaining the diversity and persistence of the organisms that comprise them. Conservation ecologists apply the principles of ecology and other disciplines, to the maintenance of biodiversity. This thesis uses this approach to assess the status of freshwater crayfish in south-central Ontario and investigate potential anthropogenic drivers of crayfish community change. I start with a temporal analysis of crayfish relative abundance over a period of 18 years and find that all species have experienced significant population declines across the sampled range, resulting in reduced species distributions and crayfish community diversity. Next I employ multivariate statistical techniques to relate changes in crayfish communities between the two time periods to ecological and anthropogenic changes. I identify a number of threats in the region that are correlated with crayfish decline and are likely to pose a threat to aquatic ecosystems more broadly in the region, including calcium (Ca) decline, metal pollution, human development, and species introductions. In the latter two chapters I look more closely at Ca decline as a mechanism driving crayfish declines. First, laboratory analysis of the effect of Ca availability on juvenile Orconectes virilis (a Shield native) reveals that survival is significantly reduced below 0.5-0.9 mg·L-1, which is one of the lowest ever reported Ca requirement thresholds for a crustacean. Second, a correlative study using adult inter-moult crayfish collected from lakes that range broadly in their Ca concentrations, indicates that for O. virilis, carapace Ca content is significantly related to lake Ca concentration, and is under-saturating below 8 mg·L-1. This collective body of work identifies significant anthropogenic threats to crayfish and their aquatic ecosystems in south-central Ontario.
Characterization of Genetically Modified HUCPVCs as an Osteogenic Cell Source.
Keywords: Runx2
Osterix
BMP-2
VEGF
Ex vivo gene therapy
Osteogenic
Mesenchymal stromal cells
HUCPVCs

Tissue engineering and ex vivo gene therapy can be used synergically as tool to regenerate bone, which overcome the problems of currently available bone replacements. Recently, a new source of mesenchymal stromal cells (MSCs) has been found in the umbilical cord; human umbilical cord perivascular cells (HUCPVCs) provide an alternative to bone marrow derived MSCs and due to their easy harvest, fast expansion, and non-immunogeneic and immunomodulatory phenotype we hypothesized that HUCPVCs are a putative candidate cell source for osteogenic ex vivo gene therapy. This work proposes the generation of cocktails of genetically modified HUCPVCs and their cryopreservation as an “off the shelf” therapeutic. This approach involves the engineering of osteogenic cell populations, by genetically modifying HUCPVCs using recombinant adenoviruses to deliver four fundamental genes for bone formation: bone morphogenetic protein 2 (BMP-2), runt-related transcription factor 2 (Runx2), Osterix (OSX/SP7) transcription factor and vascular endothelial growth factor (VEGF). Our results show that HUCPVCs can be efficiently modified by adenoviruses and can be cryopreserved without affecting the production efficiency and bioactivity of proteins of interest produced by the cells. Moreover, overexpression of BMP2, Runx2 and SP7 enhances ALP activity levels in HUCPVCs and upregulates ALP, OPN, COL1A1 and OCN gene expression; data that provides the first evidence of the effects of combinational expression of BMP2, Runx2 and SP7. Furthermore, we report for the first time the genetic modification of human BMSCs to express SP7 and Runx2, which enhances their ALP activity and matrix mineralization capacity.
Canon Law Collections in England ca 600-1066: The Manuscript Evidence
Keywords: Medieval Canon Law
Anglo-Saxon England

This dissertation summarizes the evidence for the use of canon law collections in England during the Christian Anglo-Saxon period, that is ca 600-1066. The method is text-historical, the focus being firstly on the scientific description of the primary evidence, and secondly on the evaluation of that evidence to determine which canon law collections were in circulation in Anglo-Saxon England, and exactly when, where and (in some cases) to whom they may have been available. An attempt is also made (in Chapter 2) to find a place for future discussion of canon law collections within the field of Anglo-Saxon Studies, a field traditionally resistant to this particular aspect of early medieval legal culture. This dissertation has been envisioned as primarily descriptive. Here and there, however, attempts are made to venture beyond mere description of the evidence and explore the broader significance of canon law collections to Anglo-Saxon legal culture as a whole; however, given the still nascent state of the study of Anglo-Saxon canon law, such explorations are very often speculative and can only be considered preliminary to a more detailed investigation into the social, political and institutional significance of the evidence that is herein presented. This is simply to say that the goals of the present study are more humble than might be hoped. A solid foundation, rather than a consummate edifice of historical analysis, is sought after. Indeed, it bears advertising up front that not only has the definitive treatment of Anglo-Saxon canon law yet to be written; in all likelihood, it will still be many years before it is even prudent to attempt such a thing. The appendices contain a number of transcriptions of canon law collections from Anglo-Saxon manuscripts, including the first ever transcriptions of the Collectio Sanblasiana and Collectio Turonensis, as well as transcriptions of Book 4 of the Collectio quadripartita and of the Collectio Wigorniensis (or 'Excerptiones pseudo-Ecgberhti') in four of its five redactions. The appendices also contain a review of the complex historiography surrounding the latter two collections, as well as case studies of three texts that appear to have been crucial to the development of canon law in the Anglo-Saxon church, namely the Libellus responsionum, the Constitutum Silvestri, and Ecgberht of York's Dialogus. While the appendixed material is intended primarily as support for the broader arguments developed in the dissertation proper, it is also hoped that scholars will find some of that material useful in its own right, and that it will serve to promote further discussion of the importance of canon law collections, especially Continental canon law collections, within the context of Anglo-Saxon history.
Teaching Science for Social Justice: An Examination of Elementary Preservice Teachers' Beliefs
Keywords: science education
beliefs
elementary education
urban education

This qualitative study examines the beliefs and belief changes of eleven elementary preservice teachers about teaching science for social justice. Using constructivist grounded theory, it forwards a new theory of belief change about teaching science for social justice. The theory posits that three teaching and learning conditions may facilitate belief change: preservice teachers need to recognize (1) the relationship between science and society; (2) the relationship between individuals and society; and (3) the importance of taking action on socioscientific issues. This research responds to calls by critical scholars of teacher education who contend that beliefs in relation to equity, diversity, and multiculturalism need to be explored. They have found that many preservice teachers hold beliefs that are antithetical to social justice tenets. Since beliefs are generally considered to be precursors to actions, identifying and promoting change in beliefs are important to teaching science for social justice. Such a move may lead to the advancement of curricular and pedagogical efforts to promote the academic participation and success in elementary science of Aboriginal and racialized minority students. The study was undertaken in a year-long science methods course taught by the researcher. It was centered on the preservice teachers – their beliefs, their belief changes, and the course pedagogies that they identified as crucial to their changes. However, the course was based on the researcher-instructor’s review of the scholarly literature on science education, teacher education, and social justice. It utilized a critical – cultural theoretical framework, and was aligned to the three dimensions of critical nature of science, critical knowledge and pedagogy, and sociopolitical action. Findings indicate that, at the beginning of the year, preservice teachers held two types of beliefs (liberal and critical) and, by the end of the course, they experienced three kinds of shifts in beliefs (minimal, substantial, and refined). The shifts in beliefs were attributed by preservice teachers to specific pedagogies. Yet their initial beliefs also served as filters to the pedagogies, consequently impacting their degrees of belief change. Therefore, this study reveals elements of unpredictability when engaging in teaching science for social justice.
Collaborative Research Partnerships for Knowledge Mobilization
Keywords: Collaboration
Research partnerships
Research utilization
Knowledge mobilization

This study examines the elements of collaborative research partnerships (CRPs) between university researchers and other organizations or individuals in the education sector whose mandate is to conduct and disseminate research for service delivery. Studying these partnerships for knowledge mobilization(KMb)includes understanding the roles partners take on; the tensions or facilitators they face when bringing research into practice; the structures to maintain the partnership; and the knowledge mobilization activities. Phase 1 takes an in-depth look at one partnership using key informant interviews and document analysis, while phase 2 utilizes a survey between four overarching university-community organization partnerships across Canada. Findings suggest that although difficult, when research producers and users work together, capacity is built at the organizational level to view research evidence as an important part of the organizational service delivery, with small impacts on individual knowledge development; that partnerships remain informal in their practice; that the mechanisms by which partners use to communicate within the partnership and the frequency of communication helps to build relationships between partners; and the ideal type of CRP, where they ought to always be an equal endeavour, is overstated in the literature. Not all useful partnerships are exact equal contributions from research producers and their user-based partners. Implications include that researchers gain access to practice expertise and insights into practice-based research rather than engaging in only theoretical research while community partners gain access to greater capacity for understanding and using research through exchanges with academics.
Digital Microfluidics for Multidimensional Biology
Keywords: Digital microfluidics
Microfluidics
Biology
Cell culture
3D cell culture
hydrogel

Digital microfluidics (DMF) has emerged in the past decade as a novel microfluidic paradigm. As a liquid handling technology, DMF facilitates the electrostatic manipulation of discrete nano- and micro- litre droplets across open electrode arrays providing the advantages of single sample addressability, automation, and parallelization. This thesis presents DMF advances toward improved functionality and compatibility for automated miniaturized cell culture in two and three dimensions. Through the development and integration of surface patterning techniques we demonstrate a virtual microwell method for high precision on-device reagent dispensing in one and two plate DMF geometries. These methods are shown to be compatible with two-dimensional culture of immortalized cell lines on ITO, primary cells on coated surfaces, and for co-culture assays. We further extrapolate this method for the formation of microgels on-demand where form micro scale hydrogel structures through passive dispensing in a wide array of geometries. With this system we interrogate three-dimensional cell culture models, specifically for the recapitulation of kidney epthelialization and the analysis of functional cardiac microgels.
Self-assembly Drives the Control of the SPOP Cullin–Ring Ligase
Keywords: Ubiquitin
Cullin
Self-assembly
Oligomer
E3 Ligase

The covalent modification of proteins with a suite of molecular tags, a process termed post-translational modification, is a powerful means to enhance the proteomic complexity of an organism far beyond that which is directly encoded by its genome. A particularly widespread form of modification involves the conjugation of the protein ubiquitin to specified substrates, which serves to regulate numerous cellular processes. The mechanism of ubiquitin conjugation, known as ubiquitylation, requires E3 ubiquitin ligases that specify and recruit substrate proteins for ubiquitin conjugation. Recent insights into the mechanisms of ubiquitylation demonstrate that E3 ligases can possess active regulatory properties beyond those of a simple assembly scaffold. This thesis describes the dimeric structure of the E3 ligase adaptor protein SPOP in complex with the N-terminal domain of Cul3 at 2.4 Å resolution. Here, it is demonstrated that SPOP forms large oligomers that can form heteromeric species with the closely related paralog SPOPL. In combination, SPOP and SPOPL form a molecular rheostat that can fine-tune E3 ubiquitin ligase activity by affecting the oligomeric state of the E3 complex. These results reveal a mechanism through which adaptor protein self-assembly may provide a graded level of regulation of the SPOP/Cul3 E3 ligase toward its multiple protein substrates.