VictorJuiz/thesis huggingface dataset:
Form and Function: Seeing, Knowing, and Reasoning with Diagrams in the Practice of Science

In virtue of what do scientific diagrams acquire their epistemic legitimacy? Which factors serve to validate schematic visual representations, rendering them useful and accepted components of scientific practice? This thesis addresses the epistemic legitimacy of scientific diagrams by investigating a variety of diagrams whose referents are “invisible”, that is, whose targets either cannot be seen, lack physical form, or have no material analogue. In focusing on such images, we shall gain insight into the factors that shape the forms that practicing scientists give to their diagrams and shed light on contemporary issues in the philosophy of scientific models and representations. In this work, common factors underscoring the epistemic legitimacy of scientific diagrams are identified through three in-depth historical case studies. First, we consider several diagrammatic approaches to visualizing chemical structure that emerged around the 1860s, especially the competing approaches of August Kekulé and Alexander Crum Brown, and investigate the factors that led to the enduring success of Crum Brown’s visual representations and the corresponding abandonment of Kekulé’s. Second, we examine a spectrum of stereochemical diagrams and material models produced from the 1870s to the early 20th century, particularly those produced by J. H. van ‘t Hoff, and consider the factors that determined the forms given to representations of three-dimensional structures of chemical compounds. Third, we explore the diagrammatic approaches taken by physicist Richard Feynman in his mid-20th century lectures on quantum electrodynamics, paying close attention to his diagrams’ stylistic commonalities and dissimilarities as well as their ability to mediate between various aspects of the practice of physics. Finally, this thesis concludes by considering several common factors regarding the epistemic legitimacy of scientific diagrams that can be identified in these case studies, including the importance of a bijective relationship between scientists’ understanding of their diagrams and of their diagrams’ referents, the utility of diagrams for productively reasoning about their referents, and ability of certain diagrams to reduce scientists’ cognitive burden, especially through visual similarities. These factors serve to unite divergent approaches to the philosophy of scientific models and representation and reorient contemporary debates concerning representation towards an integrated historical-philosophical methodology.

Keywords: Visual
Diagram
Reasoning
Visualization
Physics
Feynman
Chemistry
Kekule
Crum-Brown
Van 't Hoff
models
representation
Advisor: Yeang, Chen-Pang
Numerical Geodynamic Experiments of Continental Collision: Past and Present

Research explores deep continental lithosphere (i.e., the continental lower crust and mantle lithosphere) deformation during continental collision. I found that depending on the composition/rheology of the crust and the amount of radiogenic heat production in the crust, three dominant modes of mantle lithosphere deformation evolve under Neoarchean-like conditions: (1) a pure-shear thickening style; (2) an imbrication style; (3) and a "flat-subduction" style. The imbrication and the flat-subduction styles result in the emplacement of "plate-like" mantle lithosphere at depths between 200 km and 325 km. The imbrication style behavior shifts to the "flat-subduction" style behavior after a crustal inversion event. I investigated mature Phanerozoic-style collision and found that it is sensitive to mantle lithosphere density, mantle lithosphere yield stress, lower-crustal strength and to the presence of phase change-related density changes in the lower crust. The early stages of collision are accommodated by subduction of lower crust and mantle lithosphere along a discrete shear zone beneath the overriding plate. Next, the subducting lower crust and mantle lithosphere retreat from the collision zone, permitting the sub-lithospheric mantle to upwell and intrude the overriding plate. Next, the lower crust and mantle lithosphere of the overriding plate delaminate from the overlying crust. This process produces plateau-like uplift. These modeling results are interpreted in the context of available geological and geophysical observables for the Himalayan-Tibetan orogen. I quantitatively investigated the effects that sediment deposition may have on continental lithosphere deformation during collision. In the absence of sedimentation, the early stages of collision are accommodated by subduction of lower crust and mantle lithosphere beneath the overriding plate. Next, the subducting lower crust and mantle lithosphere retreat from the collision zone. This permits the sub-lithospheric mantle to upwell and come into contact with the thickened upper crust. When sedimentation is imposed subduction-like consumption of the subducting plate remains stable. Using numerical geodynamic models, I studied the influence of the pressure-dependence of viscosity on tectonic deformation during collision. At low activation volumes, high convergence rates, and low to moderate initial Moho temperatures the subduction style of mantle lithosphere deformation is dominant. At low activation volumes, high convergence rates, and high initial Moho temperatures distributed pure-shear style deformation occurs. At low activation volumes, low convergence rate, and moderate to high initial Moho temperatures the mantle lithosphere prefers a convective removal style of deformation. Increasing the activation volume of mantle material in either of these three cases changes the style of mantle lithosphere deformation because its viscosity increases non-linearly.

Keywords: Geodynamics
Advisor: Pysklywec, Russell
Educational Developers and Their Uses of Learning Theories: Conceptions and Practices

This thesis reports on a study designed to understand how learning theories fit in the practice of educational developers; specifically, developers’ conceptions of learning theories, their use of theories, and, finally, factors that influence the way learning theories shape developers’ practice. To investigate these questions, a qualitative study was undertaken with eleven Canadian university educational developers, all formally associated with a campus-wide teaching and learning centre. By taking an exploratory approach, while drawing upon learning theories and educational development literature, aspects of educational developers’ understanding and use of learning theories were highlighted. The findings showed that educational developers in this study: (i) conceptualize learning theories as lowercase ‘lt’ as opposed to uppercase ‘LT’, and (ii) define learning theories based on their prior disciplines. These practitioners didn’t associate learning theories with formal academic theories aimed at understanding a situation; instead they had formed their own synthesis of theories to help them perceive the characteristics of a particular situation. Also, the way the participants defined and conceptualized learning theories seemed to correspond to their prior disciplines and areas of study. Five definitions of learning theories were identified among educational developers: philosophy, language, educational-psychology, holistic, and neuroscience-based. In terms of how theories shape developers’ work, developers were categorized in three groups: (1) those who had a tendency to implicitly use learning theories –focusing more on practical explorations for achieving a desired outcome (seven in total); (2) developers who had a tendency to consciously use learning theories – taking more of a comprehensive approach by examining their assumptions and focusing on causes and effects that influence their practice (three in total); and, (3) one developer who had characteristics of both groups. Factors such as educational background, professional identities, and perceived audience readiness appeared to influence participants’ uses of learning theories. Seeing their work as part of a collective, and attending to the emotional needs of their audience also seemed to impact these practitioners’ work. Considering the limited research examining how educational developers conceptualize learning theories and the way theories inform their practice, this study contributes in generating discussions and future research in a community that continues to grow and situate itself within the higher education landscape.

Keywords: educational developer
learning theories
higher education
faculty developer
Advisor: Bencze, John Lawrence
Preconditioning Techniques for a Newton-Krylov Algorithm for the Compressible Navier-Stokes Equations

An investigation of preconditioning techniques is presented for a Newton--Krylov algorithm that is used for the computation of steady, compressible, high Reynolds number flows about airfoils. A second-order centred-difference method is used to discretize the compressible Navier--Stokes (NS) equations that govern the fluid flow. The one-equation Spalart--Allmaras turbulence model is used. The discretized equations are solved using Newton's method and the generalized minimal residual (GMRES) Krylov subspace method is used to approximately solve the linear system. These preconditioning techniques are first applied to the solution of the discretized steady convection-diffusion equation. Various orderings, iterative block incomplete LU (BILU) preconditioning and multigrid preconditioning are explored. The baseline preconditioner is a BILU factorization of a lower-order discretization of the system matrix in the Newton linearization. An ordering based on the minimum discarded fill (MDF) ordering is developed and compared to the widely popular reverse Cuthill--McKee ordering. An evolutionary algorithm is used to investigate and enhance this ordering. For the convection-diffusion equation, the MDF-based ordering performs well and RCM is superior for the NS equations. Experiments for inviscid, laminar and turbulent cases are presented to show the effectiveness of iterative BILU preconditioning in terms of reducing the number of GMRES iterations, and hence the memory requirements of the Newton--Krylov algorithm. Multigrid preconditioning also reduces the number of GMRES iterations. The framework for the iterative BILU and BILU-smoothed multigrid preconditioning algorithms is presented in detail.

Keywords: computational fluid dynamics
algorithms
preconditioning
nonlinear partial differential equations
Advisor: Zingg, David W.
Interaction of αβ-TCR+CD3+CD4-CD8-NK1.1- T Cells with Antigen Presenting Cells in Immune Suppression

αβ-TCR+CD3+CD4-CD8-NK1.1- double negative (DN) T cells comprise 1-5% of T lymphocytes in mice and humans. Previous studies have demonstrated that DN T cells can suppress auto-, allo- and xeno-immune responses in an antigen-specific fashion. However, the mechanisms by which DN T cells regulate immune responses remain elusive. Whether DN T cells can regulate antigen presenting cells has not been investigated previously. The focus of this thesis is to determine the consequences of DN T cells interaction with antigen presenting cells (APCs) and the underlying mechanisms. In this thesis, using a murine skin transplantation model, we found that donor B cells, but not dendritic cells (DCs), are the major surviving donor APCs in recipients following donor lymphocyte infusion. Infusing donor B, but not non-B, cells resulted in significantly enhanced donor-specific skin allograft survival. Mice that had received donor B cells showed higher expression of activation markers on antigen-specific DN T cells. B cells could present alloantigen to DN T cells and prime DN T cell proliferation in an antigen-specific fashion. Activated DN T cells were not able to down regulate the expression of CD80 or CD86 on LPS-activated B cells, but they could kill activated allogeneic as well as syngeneic B cells via a perforin-dependent pathway in vitro. In addition, DN T cells expressed high levels of CTLA4 and were capable of down regulating CD80 and CD86 expressed on antigen-expressing mature DCs through CTLA4. DN T cells killed both immature and mature allogeneic DCs, as well as antigen-loaded syngeneic DCs, in an antigen-specific manner in vitro and in vivo, mainly through the Fas-FasL pathway. Taken together, the data presented in this thesis demonstrate, for the first time, that DN T cells are potent regulators of APCs and further clarify the mechanisms of DN T cell-mediated immune suppression. These findings provide novel insights for DN T cells to be developed as a potent immune suppression treatment for a variety of diseases.

Keywords: DN T cell
APC
Advisor: Zhang, Li
AdS/CFT, Black Holes, And Fuzzballs

In this thesis we investigate two different aspects of the AdS/CFT correspondence. We first investigate the holographic AdS/CMT correspondence. Gravitational backgrounds in d+2 dimensions have been proposed as holographic duals to Lifshitz-like theories describing critical phenomena in d+1 dimensions with critical exponent z&gt;1. We numerically explore a dilaton-Einstein-Maxwell model admitting such backgrounds as solutions. We show how to embed these solutions into AdS space for a range of values of z and d. We next investigate the AdS3/CFT2 correspondence and focus on the microscopic CFT description of the D1-D5 system on T^4*S_1. In the context of the fuzzball programme, we investigate deforming the CFT away from the orbifold point and study lifting of the low-lying string states. We start by considering general 2D orbifold CFTs of the form M^N/S_N, with M a target space manifold and S_N the symmetric group. The Lunin-Mathur covering space technique provides a way to compute correlators in these orbifold theories, and we generalize this technique in two ways. First, we consider excitations of twist operators by modes of fields that are not twisted by that operator, and show how to account for these excitations when computing correlation functions in the covering space. Second, we consider non-twist sector operators and show how to include the effects of these insertions in the covering space. Using the generalization of the Lunin-Mathur symmetric orbifold technology and conformal perturbation theory, we initiate a program to compute the anomalous dimensions of low-lying string states in the D1-D5 superconformal field theory. Our method entails finding four-point functions involving a string operator O of interest and the deformation operator, taking coincidence limits to identify which other operators mix with O, subtracting conformal families of these operators, and computing their mixing coefficients. We find evidence of operator mixing at first order in the deformation parameter, which means that the string state acquires an anomalous dimension. After diagonalization this will mean that anomalous dimensions of some string states in the D1-D5 SCFT must decrease away from the orbifold point while others increase. Finally, we summarize our results and discuss some future directions of research.

Keywords: String Theory
Black Holes
AdS/CFT
Black hole information paradox
Advisor: Peet, Amanda
Learning From Rape Crisis Volunteers: Remembering The Past, Envisioning The Future

While research on sexual violence, rape crisis centres and volunteers is extensive, there are very few empirical studies that draw specifically on the experiences of rape crisis volunteers. Instead, most of the literature pertaining to rape crisis work focuses on the efforts of social workers or other paid staff. When rape crisis volunteers are examined, the focus is primarily on the context through which their work is performed, for instance, how a rape crisis centre operates in relation to other community organizations (Campbell, 1998) or whether a specific rape crisis centre upholds feminist philosophies (Maier, 2008). Studies are also usually restricted to the negative effects of rape crisis work (for example, how rape crisis workers experience anxiety, social withdrawal and vicarious trauma) or focus on what sustains rape crisis workers while working in a stressful environment (Baird and Jenkins, 2003; Hellman and House, 2006; Thornton and Novak, 2010; Wasco and Campbell, 2002). Using the life history approach, this study builds on previous research and explores the experiences of volunteers at rape crisis centres across Ontario, Canada. In particular, the following issues were examined: motivations to volunteer, personal challenges and tensions, as well as challenges with respective centres. Findings indicate that all participants in the study have directly and/or indirectly experienced a range of different kinds of violence. Also, participants noted a range of complex and interconnected motivations for their initial and ongoing involvement in rape crisis work, most notably, self-healing. Finally, most participants expressed hesitancy towards identifying as feminists and did not associate feminism and the anti-violence movement as being strictly related to women. Theorizing the experiences of rape crisis volunteers through the lens of standpoint theory offers a new approach to knowledge construction in the area of rape crisis work and points towards the way that services, including training, can be improved for volunteers. Furthermore, the life history approach offers a unique way to understand the experiences of rape crisis volunteers in greater depth and breadth, since attention was placed on the volunteer process as well as other life experiences.

Keywords: violence against women
rape crisis work
volunteers
life history
standpoint theory
feminism
Advisor: Gérin-Lajoie, Diane
Race, Gender and Interuniversity Athletics: Black Female Student Athletes in Canadian Higher Education

Despite the documented history of women's athletics and minority students' participation in Canadian postsecondary institutions, little is known about Black female student athletes and their experiences within Canadian higher education. This dearth of information is paradoxical considering the academic and athletic legacy of this subgroup, as well as the noted importance of the student experience and athletic participation within Canadian universities. The aim of the study was to gather data on the experiences of Black female undergraduate students involved in varsity athletics. The goal was to gain an understanding of their experiences as students, as athletes, and as Black women. Additionally, the study intended to help fill a gap in the existing literature on race, sport, and the student experience in the Canadian context. The study employed an intersectional framework to examine how race, gender, athleticism and the student role intersect to shape the student experience. The investigation utilized a mixed method approach consisting of an online survey and in-depth interviews. This national study included participants from each of the four Canadian Interuniversity Sport (CIS) regions. Twenty-eight Black female student athletes completed the online survey, while an additional thirty-two Black female student athletes were interviewed. The findings were divided into seven major themes: University Expectations versus Reality, Pressure and Positivity, Complex Relationships, Unique Experiences, Negotiating and Navigating, Hiding and Highlighting and Levels of Blackness. In a number of ways, the Black Canadian female student athlete's experience is similar to that of other student athletes. However, it also was found that Black female student athletes have a unique experience due to the intersection of their race, gender and athleticism. Thus, Black female student athletes have a distinct experience as they deal with racial, gender, and athletic stereotypes; the underrepresentation of Black females and Black female athletes in higher education; the intricacies of Black dating and intimate relationships; and the complex interactions within the Black communities on campus.

Keywords: Higher Education
Student Athletes
Black Canadians
Advisor: Chambers, Tony
Structure and Properties of Electrodeposited Nanocrystalline Ni and Ni-Fe Alloy Continuous Foils

This research work presents the first comprehensive study on nanocrystalline materials produced in bulk quantities using a novel continuous electrodeposition process. A series of nanocrystalline Ni and Ni-Fe alloy continuous foils were produced and an intensive investigation into their structure and various properties was carried out. High-resolution transmission electron microscopy (HR-TEM) revealed the presence of local strain at high and low angle, and twin boundaries. The cause for these local strains was explained based on the interpretation of non-equilibrium grain boundary structures that result when conditions of compatibility are not satisfied. HR-TEM also revealed the presence of twin faults of the growth type, or &ldquo;growth faults&rdquo;, which increased in density with the addition of Fe. This observation was found to be consistent with a corresponding increase in the growth fault probabilities determined quantitatively using X-ray diffraction (XRD) pattern analysis. Hardness and Young&rsquo;s modulus were measured by nanoindentation. Hardness followed the regular Hall-Petch behaviour down to a grain size of 20 nm after which an inverse trend was observed. Young&rsquo;s modulus was slightly reduced at grain sizes less than 20 nm and found to be affected by texture. Microstrain based on XRD line broadening was measured for these materials and found to increase primarily with a decrease in grain size or an increase in intercrystal defect density (i.e., grain boundaries and triple junctions). This microstrain is associated with the local strains observed at grain boundaries in the HR-TEM image analysis. A contribution to microstrain from the presence of growth faults in the nanocrystalline Ni-Fe alloys was also noted. The macrostresses for these materials were determined from strain measurements using a two-dimensional XRD technique. At grain sizes less than 20 nm, there was a sharp increase in compressive macrostresses which was also owed to the corresponding increase in intercrystal defects or interfaces in the solid.

Keywords: nanocrystalline
nickel
nickel-iron
characterization
properties
hardness
Young's modulus
microstrain
internal stress
grain boundary
Advisor: Erb, Uwe