VictorJuiz/thesis huggingface dataset:
White Matter Microstructure and Emotional Functioning in Children Treated for Posterior Fossa Tumours
Keywords: Diffusion tensor imaging
Eye-tracking
Neuropsychology
Paediatric brain tumours
White matter

Children treated for brain tumours that arise in the posterior fossa (PF) experience lifelong cognitive and emotional difficulties, and exhibit white matter (WM) damage. This thesis combined diffusion tensor imaging (DTI), eye-tracking and standardized measures of cognitive and emotional functioning in children treated for PF tumours and typically developing children, to: 1) characterize outcomes related to decreases in treatment intensity, 2) objectively evaluate emotional functioning, and 3) examine the associations between WM microstructure and emotional functioning. It was found that treatment with the lowest intensity craniospinal irradiation protocol spared WM in the temporal lobe of children treated for malignant PF tumours. In addition, patients treated on lower intensity protocols had largely preserved cognitive, social and affective functioning. However, novel eye-tracking tasks designed to evaluate emotional functioning uncovered some remaining deficits; children treated for PF tumours had difficulty recognizing facial emotions despite attending to the faces, and difficulty regulating their initial attention away from emotional faces. Notably, this eye-tracking measure of emotion regulation was associated with emotional control in daily life. The current work also revealed that relations between WM microstructure and emotional functioning can diverge in the injured and uninjured brain; WM predicted facial emotion recognition in typically developing children only, whereas WM was associated with emotion regulation in patients only. In a field dominated by findings that characterize negative sequelae, this work highlights the possibility of favourable outcomes for PF tumour patients who are eligible for treatment with lower intensity protocols. Despite these positive outcomes, subtle emotional functioning deficits not captured by standardized questionnaires persist. To better understand how emotional processes are altered in children treated for PF tumours, novel objective measures are required. This thesis detailed one such behavioural marker to evaluate emotion regulation, using eye-tracking technology, and characterized an oculomotor response that may warrant interventional follow-up.
Merchants of War: Mercenaries, Economy, and Society in the Late Sixteenth-century Baltic
Keywords: Estonia
Landsknecht
Livonia
Livonian War
mercenaries
Sweden

The polities of the sixteenth-century Baltic competed and cooperated with one another and with local power groups in fluctuating patterns of rivalry and expedient partnership. Mercenarism thrived in this context, as early modern governments were seldom equipped with the fiscal and logistical tools or the domestic military resources needed to wholly meet the escalating challenges of warfare, while mercenaries themselves were drawn to a chaotic environment that afforded opportunities for monetary gain and promotion into the still-coalescing political elites of the region’s emerging powers. This study sits, like the mercenary himself, at the intersection of the military, the economic, the social, and the political. Broadly, it is an analysis of mercenaries in Livonian and Swedish service during the so-called Livonian War of 1558 to 1583. Mercenaries are examined as agents of the polities for whom they fought and as actors with goals of their own, ambiguously positioned figures whose outsider status and relative independence presented both opportunities and challenges as they navigated the shifting networks of conflict and allegiance that characterized their fractious world. The aims of this study are threefold. The military efficacy of Western and Central European professional soldiers is assessed in an Eastern European context, problematizing the notion of Western military superiority in a time of alleged military revolution. The effects of prolonged warfare on Estonian and Livonian society are examined with an eye on interactions between local communities and the foreign soldiery, as well as on the ramifications of increasing participation in military enterprise by segments of the Livonian population. Mercenarism is also analyzed as a key site of the early modern struggle for greater governmental control over the economy and legitimate violence, whether through the cooption of privileges traditionally enjoyed by non-state and local power groups or through partnership between these factions and centralizing governments.
Enhancing GPR Surveys By Utilizing Dispersive Properties and Phase Information
Keywords: Dispersion
GPR
Phase
Radius estimation

Ground-penetrating-radar (GPR) is a non-destructive testing method that utilizes the transmission or reflection of electromagnetic (EM) waves to locate anomalies beneath a surface. GPR is now widely used in mining, civil engineering, environmental sciences, and archaeology to survey the subsurface. In a conventional GPR survey, only the arrival time of the EM pulse is used to obtain an estimate for the depth of a target. There is much more information incorporated in GPR records that can be used to infer conditions below the surface. This thesis aims to enhance GPR surveys by utilizing material properties and signal processing. Large quantities of systematic data are necessary for completing the two projects; therefore, a numerical simulation tool is developed. A 2D finite-difference-time-domain (FDTD) simulation of EM wave propagation is established using MATLAB. Dispersive materials described by N-term Debye models can be simulated by the algorithm, which facilitates studies on dispersive materials. Contrary to common assumptions, some materials, especially those that are wet, have frequency-dependent relative permittivities. The dispersion in velocity changes the shape of the source pulse during propagation and poses a challenge for travel time estimation. Instead of treating dispersion as an obstacle to GPR applications, a novel method of distinguishing dispersive materials by estimating quality factor (Q*) is proposed in the thesis. Using a combination of laboratory measurements and modelling results, it is shown that GPR signals can be used to identify dispersive behaviours. On the signal processing side, a method of estimating radii of cylindrical objects from phase information is demonstrated. In contrast to previous studies, the phase information of reflected signals have better resolution and are closer to theoretical values compared to arrival time analysis. The method, with limitations investigated through uncertainty calculations, is applied to both numerical examples and real GPR data for testing.
Swallowing Physiology and Impairment in Individuals with Amyotrophic Lateral Sclerosis (ALS)
Keywords: dysphagia
swallowing
videofluoroscopy

Dysphagia, or swallowing impairment, is a common symptom of bulbar disease in Amyotrophic Lateral Sclerosis (ALS). Dysphagia in ALS significantly affects quality of life and places an affected individual at risk of developing chest infections, becoming malnourished, and shortened life expectancy. The purpose of this doctoral thesis is to provide a comprehensive overview of swallowing physiology in ALS and elucidate potential relationships between swallowing physiology and clinical swallowing function. The first chapter of this thesis provides an introductory overview of normal swallowing, dysphagia, and ALS pathology, highlighting commonly reported swallowing impairments and associated complications in individuals with ALS. Chapter 2 builds on this discussion through a comprehensive review of research literature on dysphagia in ALS. Following scoping review methodology, we identified research trends and areas for further exploration, including a need for further quantitative analysis of swallowing physiology. Chapter 3 involves a retrospective, cross-sectional study of swallowing physiology in ALS, using quantitative videofluoroscopic analysis. Measures of pharyngeal area at maximum constriction and swallow-related hyoid kinematics were obtained and compared against reference data to test face validity of the measures and identify changes associated with disease pathology. Through this analysis, we identified reductions in maximum pharyngeal constriction and anterior hyoid movement, compared to healthy reference data. Further, we revealed relationships between enlarged maximum pharyngeal constriction areas and measures of swallowing inefficiency. Expanding on these findings, we completed a comprehensive summary of swallowing physiology and function in ALS, summarized in Chapter 4, comparing additional metrics of swallowing physiology against healthy norms, examining relationships between parameters of swallowing physiology and function (i.e., safety/efficiency), and exploring modulatory effects of liquid thickness. Proposed approaches to future research, incorporating theories of motor control and methodological frameworks, are provided in Chapter 5.
Extending the Breadth of Metal Halide Perovskite Applications to the Control and Modulation of Light
Keywords: Electro-optics
Hybrid
Nanomaterials
Nonlinear Optics
Perovskites
Photonics

The rapid rise of metal halide perovskites as photovoltaic materials has been an impressive achievement. Their performance as solar energy harvesters stands out amongst solution processed materials. Metal halide perovskites have also emerged as efficient light emitters for potential use in light emitting diodes and lasers. Their promise derives from a combination of their solution processing, desirable optical and electronic properties, and compositional flexibility. Perovskites can be engineered to have sharp absorption onsets, high photoluminescence quantum yields, and low trap state densities. In this thesis I present applications of metal halide perovskites in the control and modulation of light. I expand their applicability by exploiting nonlinear and electro-optic processes in these materials. I begin by investigating the electro-optic behaviour of germanium halide perovskites. The electro-optic coefficients of these compounds are calculated using density functional theory. CsGeI3 is predicted to have an electro-optic coefficient of 47 pm·V-1 at the communications wavelength of 1550 nm, exceeding the greatest coefficient of lithium niobate. This study is the first exploration of the linear electro-optic process in metal halide perovskites. Next, I study quantum-confined Stark effects in layered perovskites. Electroabsorption spectroscopy is conducted with thin films of two-dimensional metal halide perovskites featuring either methylammonium or cesium cations bound in the quantum well structures. While the cesium compounds display conventional energetic red-shifts, methylammonium compounds exhibit blue-shifts. These anomalous blue-shifts are attributed to extraordinary weakening of the exciton binding energy ultimately induced by polarization of the methylammonium dipoles. Both the red-shifts and blue-shifts are engineered to produce modulations in the amplitude of the absorption coefficient of 70 cm-1 for 56 kV·cm-1 applied fields, the strongest modulation amplitudes reported for solution processed materials at room temperature. Lastly, I characterize two-photon absorption in methylammonium lead bromide perovskite crystals. I determine the nonlinear absorption coefficient, along with its polarization dependence. A two-photon absorbing photoconductor was fabricated to autocorrelate ultrafast laser pulses and demonstrate the applicability of this process in metal halide perovskites.
Expertise in the Age of Digital Fabrication
Keywords: Automation
Digital Fabricaiton
Expertise
History of Computing
Labour
Prosthetics and Orthotics

This dissertation investigates the history, development, and practical application of digital fabrication. I leverage past and current scholarship from the fields of information, science and technology studies, and the history of computing in order to examine the themes of automation, control, and expertise. As current developments in artificial intelligence demonstrate, emerging computational technologies continue to re-configure normative roles and relationships in society. Previous studies of computation and labour have demonstrated that certain kinds of abstract expertise or knowledge are privileged by these changes. Understanding how and why certain kinds of abstract expertise and knowledge were privileged in the past, and how this informs current versions of these systems, is therefore critically important given the current rhetoric around automation and the future of work. My research seeks to actively re-engage the role human actors play in the technological mediation of labour, addressing the epistemic hierarchies produced by digital design and manufacturing technologies. I accomplish this by combining historical analysis of archival resources and ethnographic fieldwork to examine the origins of numerical control (N/C) and computer-aided design (CAD) in manufacturing and their shift into new professional contexts, specifically the field of prosthetics and orthotics (P). I chose P because the labour and expertise utilized by the profession is separate from the epistemic considerations of digital fabrication. As such, specific sets of knowledge practices within the field of P do not translate cleanly to computational outcomes. Yet, I found that professionals within this context were willing to adopt these technologies as it allows for their expertise and labour to be expressed to those outside the profession. Within the context of information studies, this dissertation provides the historical and evidentiary ground work necessary for understanding and addressing the processes behind why certain kinds of labour, expertise, and knowledge become configured as appropriate for humans.
Wireless Sensors using Radio-frequency Identification Technology: Developing Carbon Nanocomposites for Improved Sensing and Detection of Ammonia Gas and Volatile Amine Vapors
Keywords: Ammonia
Chemical sensors
Doping
Graphene
Polyaniline

Nowadays, the emergence of Radio-Frequency Identification (RFID) devices at costs comparable to barcodes are providing an incredible opportunity for designing interconnected networks of “things” that allow for the wireless identification of products and monitoring of the chemical composition of the surrounding environment. This has major implications for the chemical and food sectors, for which the design of interconnected networks with sensing capabilities has many practical applications. My thesis focuses on exploiting the advantageous characteristics of novel carbon nanomaterials, carbon nanotubes and graphene to design conductive nanocomposites with improved sensing capabilities for ammonia gas and amine vapours. For this purpose, we developed two types of conductive nanocomposites; one that consisted of carbon nanomaterials, maleic anhydride and electrically insulating polyethylene-co-vinyl acetate polymer matrix; and the other that consisted of carbon nanomaterials and an intrinsically conductive polymer, polyaniline. For the first type of nanocomposite system, we demonstrated that grafting the maleic anhydride on the carbon nanotubes significantly improved the sensitivity of the nanocomposites toward amines. It was postulated that these improvements were the result of the binding of putrescine between the carbon nanotubes, which facilitated a more effective disruption of the conductive network. For the second type of nanocomposite, we demonstrated that conferring n-type semiconductive behavior to the graphene nanosheets, via nitrogen or phosphorus doping, improved the sensitivity of graphene/polyaniline nanocomposite by a factor 2 and 5, respectively, to reach a detection limit in the sub-ppm range toward ammonia gas. The enhancement was due to the formation of localized p-n heterojunctions in the nanocomposites and the modification of the semiconductive behavior of the nanocomposite during exposure to ammonia. Furthermore, we tested the novel polyaniline/phosphorus doped graphene nanocomposite sensing elements on RFID split-ring resonators and showed that the wireless sensor had excellent detection capabilities toward ammonia gas down to the sub-ppm range of concentration. Based on the sensing performance achieved, this thesis demonstrates the potential of RFID technology as a platform for the design of wireless sensor networks with high detection capabilities, and are thus practically applicable in the chemical, medical and food sectors, among others.
A Living History (1973-1993): How the Experiences of Early Activists Shaped the Violence Against Women (VAW) Movement in Ontario: A Case Study
Keywords: case study
critical feminist theory
domestic violence
feminism
social movements
violence against women

This dissertation shines a light on a group of women who helped to create a violence against women (VAW) movement that changed the course of history in Ontario, Canada for countless women, their families and their communities. This study centres the voices of activists, positioning them as knowledge producers with expertise and wisdom gleaned during five decades of work in the VAW movement in Ontario. A feminist analysis of the VAW movement begins from the standpoint of women. In particular, an intersectional feminist analysis begins from the standpoint of diverse women who embrace the tenets of critical feminist standpoint theory. This study draws on social movement theory (SMT) literature, particularly the scholarship of feminist SMT researchers, to examine the state of the VAW movement in Ontario, Canada. This dissertation is a story about a social movement, specifically the VAW movement in Ontario—a strand of the women’s liberation movement frequently referred to as the second wave, but also on the cusp of ushering in third wave feminism. I document the time period from 1973 to 1993—a period that spans the start of the era when all of the participants in this study began their activist work—until the time of their interviews, which took place between 2014 to 2018. In this dissertation, I challenge the notion that the VAW movement has been reduced to a VAW sector, merely creating and delivering services to select populations of women. This interpretation suggests that there is a loss or erosion of an expressed political commitment to uncovering and eliminating the root causes of VAW. Using a case study methodology, I argue that the VAW activists in this study have been persistently engaged in and committed to ending VAW, although their activism shifts and manifests in several forms throughout the life cycle of the movement. The findings of this dissertation research are intended to bring practical and useful implications that can enhance future strategies for change in the VAW movement, contribute to the knowledge base of social work, and infuse the VAW movement with renewed energy and critical vision.
Implementing Dialectical Behaviour Therapy: An Exploratory Study of Fidelity and the Fidelity-adaptation Relationship
Keywords: Complex health interventions
Dialectical Behaviour Therapy
Implementation science
Mental health
Program evaluation
Program outcomes

Objective: The aim of this study was to improve conceptual clarity of implementation fidelity, the degree to which a program adheres to the original program protocol, and the relationship between fidelity and adaptation of a complex health intervention, Dialectical Behavior Therapy (DBT). Methods: Employing a mixed-methods approach, this study utilized secondary DBT client outcome data collected over a one-year period and semi-structured interviews with DBT therapists (program implementers). The study design was informed by the Conceptual Framework for Implementation Fidelity (CFIF) (Carroll et. al, 2007). This framework was adapted to include three categories of factors: individual client (needs, trajectories), programmatic/organizational and program implementer perspectives. Results: Findings suggest that reconceptualization of fidelity and the fidelity-adaptation relationship may require integrating stakeholder knowledge of organizational constraints, experience and values of front-line staff and heterogeneous client trajectories to allow for a more realistically flexible model that is contextually and situationally sensitive. Conclusions: Expanding the CFIF framework offered new insights regarding factors that have the potential to affect the fidelity-adaptation relationship.
Essays on Capital Structure and Firm Investment
Keywords: Capital structure
Debt overhang
Investment
Production flexibility

In this thesis, I study the interactions between firms' capital structure and real decisions. First, I investigate how a firm's financial leverage will impact its investment contingent on whether future growth opportunities are anticipated. Second, I test the under and over investment hypothesis related to debt financing contingent on whether the firm is likely to under or over invest. Last, I investigate how a firm's production technology can impact its production and capital structure decisions. In Chapter 1, I investigate the impact of anticipations of future growth opportunities on leverage-investment interactions. I show that when growth opportunities are unanticipated, the negative impact of leverage on investment is up to two times larger than when they are anticipated. The presence of institutional stockholdings significantly reduces the under investment problem. An instrumental variable analysis reveals that the leverage-investment relationship is weak when the problem of endogeneity is controlled. The results provide strong evidence that Canadian firms take ex ante leverage adjustments to mitigate the debt overhang problem. Chapter 2 studies the extent to which leverage-investment interactions depend on the level of initial investment as well future investment opportunities in US firms. I find a strong negative relationship between leverage and investment for firms with low levels of (initial) investment and high investment opportunities. I also find a positive relationship between leverage and investment for firms with high levels of (initial) investment and low growth opportunities. I distinguish between Tobin's Average Q and Marginal Q as proxies for firms' investment opportunities and propose a novel method to estimate Marginal Q. Chapter 3 is a joint work with Varouj Aivazian. In this chapter, we investigate the interactions between the flexibility of a firm's production and its financial structure. This chapter shows that production flexibility is an important factor explaining the cross sectional variations in financial leverage among U.S. firms. Alternative empirical measures of production flexibility are all shown to be positively associated with financial leverage. This chapter also develops a novel measure of inter-temporal production flexibility and identifies important linkages between production and financing decisions.