VictorJuiz/thesis huggingface dataset:
The Impact of Spoken Semantic Threat on Cognitive and Linguistic Processing Involved in Spoken Language Following a Traumatic Brain Injury (TBI)

A traumatic brain injury (TBI) significantly impacts many functions, with changes in emotional and social behaviours being among the most debilitating consequences. Accruing literature attests to emotion processing deficits in this population, with a particular impairment in processing negative emotions (including semantic threat) across visual and auditory modalities (Bornhofen McDonald, 2008; Croker McDonald, 2005; Maki-Marttunen et al., 2015). Impairments in processing negative emotions may lead to problems in interpersonal interactions, which could significantly impact the quality of life for individuals with TBI (Dijkers, 2004; Henry, Phillips, Crawford, Theodorous Summers, 2006). Despite the growing prevalence of emotion processing deficits in the TBI population, there is still a paucity of research investigating the extent and nature of these deficits. Importantly, no study to date has directly examined the impact of spoken semantic threat, particularly in the context of how it may hinder cognitive and linguistic processes used in spoken language as part of everyday conversation. Thus, a novel paradigm known as the Linguistic Acoustic ThreaT Effect (LATTE) was employed in three experimental studies to examine this impact in more detail. Results from Study 1 showed that individuals with TBI were impacted by spoken semantic threat to a greater extent than healthy matched controls. Results from Study 2 showed that the threat effect has a physiological basis in terms of increased autonomic arousal and varies in the extent of the impact based on the content of threat presented. Lastly, the results of Study 3 demonstrated that semantic threat seems to have a critical period during which it exerts its impact, and is most observable during the stages of speech processing following the immediate presentation of the verbal threat, as tested in our sequence of tasks. Taken together, our results reveal important information on the impact of semantic threat on cognitive and linguistic processes used in spoken language after TBI. Our findings could have potential implications for the training of rehabilitation clinicians and researchers regarding emotion expression when communicating with individuals with TBI.

Keywords: cognition
emotion processing
language
semantic threat
speech processing
traumatic brain injury
Advisor: van Lieshout, Pascal
Applications of boronic acids, boronates, and borates as catalysts or promoters for chemical transformations

The central theme of the research outlined in this thesis is to develop synthetic applications of organoboron compounds as catalysts or promoters. Chapter 1 emphasizes the physical properties of boronic acids and borates. Relevant applications that exploit boronic acid Lewis acidity and the ability to form reversible covalent interactions with alcohols and carboxylic acids are reviewed. In chapter 2, boron-based Lewis acid- and Brønsted acid-catalyzed Fischer glycosidations were explored. In this study, protected C-(1)-hemiacetal sugars were activated towards O- and S-glycosidations with boronic esters and borates. Chapter 3 describes our efforts towards an efficient protecting group free Fischer glycosidation under mild conditions. In this study, boronic acids were used as transient protecting groups and phase-transfer reagents for sugars in low-polarity solvents. We also found that the binding of boronic acids to free sugars changed the thermodynamic profile of the Fischer glycosidation. In chapter 4 we report a method for protodeboronation of electron-neutral and electron-rich arylboronic acids with electron-deficient β-hydroxy acids and mildly acidic additives. Calculated transition state energies supported the experimentally observed trends for the protodeboronation of arylboronic acids. Finally, progress was made towards extending the protodeboronation protocol to deuterodeboronations of arylboronic acids.

Advisor: Taylor, Mark S
Herodotean Journeys: Diversity and Political Judgment in Herodotus’ Histories

In his Histories, the ancient Greek Historian Herodotus posits that to mock other cultures is sure proof of madness, for “If there were a proposition put before mankind, according to which each should, after examination, choose the best customs in the world, each nation would certainly think its own customs the best.” (Histories, 3.38). Herodotus thus suggests how difficult it is to judge across cultures; even ‘after examination, judgment is constrained by conventional boundaries. Yet in his Histories, Herodotus himself continually examines other cultures; he is able to genuinely engage with the diversity of his world. In this dissertation, I argue that Herodotus therefore models a way of engaging with diversity, precisely because he attends to the affective attachments that often impede such investigation. His work therefore offers a therapy of judgment for his readers, one accomplished through the way Herodotus’ artful narrative inserts his audience into his story; the spectating audience is led to inquire into difference, to feel the excitement of inquiry, and, occasionally, to suffer a chastening recognition when such looking goes awry. The inquirer can be heroic, like Herodotus, wrestling with competing logoi and saving them from the ravages of time. But Herodotus uses textual foils to demonstrate some of the pitfalls that can befall inquiry. The inquirer can be a mere voyeur; hobbled by conceptual errors; a mad imperialist; or one’s inquiries can be barren, kept private and to oneself, offering no aid or insight to one’s community. Herodotus’s example transcends these foils. Yet Herodotus does not merely show these errors; he lets the audience ‘feel’ them, and so be implicated in these marred inquiries. These painful recognitions lead his audience to suffer vicariously with others, and so to gain insight usually won too late. His method, which recruits and thus rehabilitates the attachments of his audience, thus helps to communicate the substance of his inquiries. To rehabilitate the attachment of his audience, Herodotus must spark the desire to inquire for its own sake. To do this, Herodotus reveals that attending to diversity matters because the multiplicity of cultures reveals the complexity of nature. Attending to diversity allows us to understand ourselves as human beings. Herodotus, the first historian, suggests that the purpose of history - in Greek, inquiry - is not simply to determine the facts and dates of what happened, but rather to inquire into what mankind has brought into being: not only what happened, but our stories about what happened: customs, traditions, and songs. His inquiry is into what these phenomena reveal about who we are.

Advisor: Orwin, Clifford
Signal Normalization Strategies Towards Robust Carbon-13 Imaging for Clinical Translation

Prostate cancer is a heterogeneous disease. Some patients present with rapid progression, while many others never exhibit clinical symptoms. Difficulties in assessing risk of disease progression with currently available medical imaging modalities lead to treatment of both groups. However, inappropriate treatment of an indolent disease can have potential side effects with little benefit to the patient. Hyperpolarized ¹³C magnetic resonance imaging is presented as a modality that can detect increased lactate production associated with transformation to metastatic disease. An increased ¹³C lactate signal may be a valuable early indication of disease progression for patients under active surveillance. There is currently no consensus on how to interpret the observed lactate signal. In this dissertation, three signal normalization techniques are presented to prospectively account for the experimental factors of spin polarization, substrate delivery, and off-resonance. Dynamic nuclear polarization confers a temporary signal enhancement resulting from a non-equilibrium spin polarization. The polarization decreases with time due to longitudinal relaxation. For pyruvate, a spectral feature known as asymmetry can be correlated with the spin polarization. Calibration data were acquired as an empirical relationship between asymmetry and spin polarization. By prospectively accounting for the spin polarization, the normalized signal better reflects the metabolic activity in the tissue. Low ¹³C lactate signal could be attributed to slow metabolic activity or poor substrate delivery. Normalization of ¹³C lactate by the signal intensity of a co-polarized perfusion agent is proposed as an approach to account for substrate delivery. Spectrally-selective signal excitation schemes can greatly simplify signal encoding requirements, but the frequency sensitivity can also lead to incomplete excitation and imaging artifacts if the prescribed excitation frequency does not match the resonance frequency of the signal of interest. A modified pulse sequence with wider spectral passbands and multi-echo acquisition is proposed as a prospective flip angle normalization strategy. The dissertation concludes with a presentation of the current state of clinical translation of hyperpolarized ¹³C imaging technology in Toronto. The first ¹³C image of the human heart is shown along with preliminary data from the prostate cancer clinical trial.

Keywords: cancer
carbon-13
lactate
magnetic resonance imaging
metabolism
Advisor: Cunningham, Charles H
From Right to Left: Interhemispheric Interactions while Seeing Words and Hearing Sentences

The corpus callosum is the largest fiber bundle in the human brain and mediates communication between cerebral hemispheres through a combination of excitatory and inhibition interactions. The balance between excitation and inhibition has been clearly defined for certain perceptuomotor processes, but not with language. This dissertation outlined the interhemispheric interactions involved in sentence comprehension in aphasia patients (studies 1 and 2) and word recognition in healthy adults (studies 3 and 4). Aphasia is commonly associated with right hemisphere activation, which has been attributed to both inhibitory and excitatory mechanisms. Study 1 demonstrated a positive relationship between left hemisphere dysfunction and right hemisphere language activation, which could have resulted from either disinhibition or excess recruitment of the right hemisphere. Study 2 examined these two hypotheses using Dynamic Causal Modelling of fMRI. Healthy controls showed no evidence for interhemispheric homotopic inhibition, but instead demonstrated excitatory right-to-left connectivity between primary auditory cortices. Critically, auditory connectivity was associated with language recovery in patients; the worst performing patients lacked typical right-to-left excitation, and showed atypical left-to-right excitation. Studies 1 and 2 provide two very interesting results: 1) healthy language processing requires asymmetrical right-to-left perceptual transfer and 2) right hemisphere activation in aphasia results from atypical excitatory recruitment. Interhemispheric interactions between perceptual regions was further explored in study 3 using a lateralized lexical decision task with MEG. In line with results from study 2 and the broader word recognition literature, the results showed an asymmetrical transfer of visual information from right to left hemisphere. Importantly, the results add to the current literature by demonstrating transfer between primary visual cortices, at one of the earliest processing stages of word recognition. Finally, study 4 showed that simultaneous bilateral word recognition was facilitated when word pairs were semantically related. These findings again suggest that the interhemispheric interactions in word recognition are primarily excitatory. The four studies in this dissertation found consistent evidence for interhemispheric excitation in language processing. While there is clear evidence for inhibition in some language processes, the current studies suggest that both sentence comprehension and visual word recognition are primarily associated with excitatory interhemispheric interactions.

Keywords: Aphasia
Hemispheric interactions
Language
Word recognition
Advisor: Meltzer, Jed A
The Politics of Skepticism: Montaigne and Zhuangzi on Freedom, Toleration, and the Limits of Government

Contemporary political discourse often centers on a shared set of normative commitments: freedom, toleration, and limited government. This dissertation examines the theoretical basis for these commitments, through a comparative study of two eminent skeptics: Michel de Montaigne and Zhuangzi. Both develop forms of skepticism that are rooted in analyses of the phenomena of diversity and disagreement. They contend that our inability to reach convergence on central philosophical questions demonstrates the fundamental limitations of human knowledge. I argue that both offer novel and powerful arguments connecting these skeptical epistemological theses with the relevant normative commitments. In particular, both take skepticism to advance human freedom, by clearing away obstacles to effective action. As beings who are raised within a particular community, we inevitably acquire certain habits that constrain the forms of thought and action open to us. Skepticism helps us to recognize the contingency of those forms. In the interpersonal realm, both writers contend that skepticism generates an attitude of toleration towards others who live differently. This is because it undermines the theoretical claims upon which most forms of intolerance are constructed. I defend this claim with reference to the various forms of intolerance that existed in each writer’s context, Warring States era China and France during the Wars of Religion. Later chapters examine the political implications of these forms of skepticism. I argue that both writers suggest that skepticism helps to eliminate potentially dangerous political passions, notably personal ambition and the desire for glory. This leads to a more constrained view of government that encourages us to focus our attention on avoiding extreme cruelty and violence rather than pursuing grand political projects.

Advisor: Orwin, Clifford
MICROSIMULATING WEEK-LONG OUT-OF-HOME TRAVEL/ACTIVITY PATTERNS

This thesis reports on significant progress in several aspects of activity-based travel demand modelling. The major contribution is extending the time-frame of the activity-based models by developing two week-long travel/activity patterns prediction models. The two models differ in the way they schedule work activities. In the first model, work, school and night sleep are considered as the skeleton schedule around which non-work/school activities are organized. Weekly work activities are scheduled in a separate framework applying the concept of a “project” which consists of work episodes which are planned prior to the week (preplanned) and episodes planned during the week (unplanned). These episodes are generated and scheduled in a two-level, weekly, dynamic framework. In the second model, night sleep is the only skeleton schedule and the rest of the activities including work and school are generated and scheduled simultaneously. The results indicate the significance of developing models with longer planning horizon than a typical weekday. The other main contribution of the thesis is investigating the influence of a fundamental assumption in activity-based modelling which is assigning a higher priority to scheduling work/school activities on the predicted travel/activity pattern of the non-work/school activities. The thesis also tests the forecasting ability of the developed models, something which is rarely done in the literature. The modelling structure applied in this thesis is estimated on two different datasets: a small-sample computerized activity survey with a fine level of disaggregation and high level of detail of the activity and socioeconomic attributes, and a large-sample trip-based dataset with a high level of aggregation and few number of socioeconomic attributes. Simulated schedules applying models developed on each dataset indicate that using the activity survey leads to a more accurate and behaviourally representative model. The study also demonstrates the importance of a higher level of disaggregation of activity types than occurs in common practice.

Keywords: Activity-based
Discrete choice modelling
Microsimulation
Random utility maximization
Travel demand modelling
Week-long
Advisor: Miller, Eric J
Habib, Khandker Nurul
Cyber-Physical Modeling and Analysis for Smart Grids: Resiliency Cyber Security

Traditional resiliency studies of infrastructure system such as the power grid focused on a context defined by extreme events and natural disasters. However, the increased dependability on cyber tools and networks combined with the rise of serious cyber-based threats thrust resilience to be a strategic approach for planning, design and operation. This dissertation invests on a cyber-physical model of the smart grid and is motivated by the benefits of understanding the interactions between the cyber and physical domains and coordinating adaptive capacity resources for an enhanced resilient operation. We first consider how to improve the resilient operation of existing power systems. We adopt an energy storage (ESS)-based feedback linearization control to address transient stability. The control is studied in centralized, distributed and decentralized architectures, then the different architectures are recognized as modes of operation of an adaptive controller that responds to cyber and physical disturbances. Observed performance limitations of the proposed control are investigated in our study of cyber-physical interactions. A cyber-physical hybrid graph is constructed based on an equivalent impedance interpretation of a communication link performance in relation to physical power systems’ dynamics. The proposed hybrid graph constitutes a representation of the system in the cyber-physical domain. The impact of the ESS-based control in enhancing transient stability is then studied from a resiliency perspective. The combined impact of the ESS, sensory and associated control is analytically studied using a proposed effective virtual inertia measure. The proposed measure reflects the adaptive capacity introduced into the power system by the ESS-based control. We next consider evolving distribution systems and how coordinated operation of these systems can adopt a resilient-by-design approach. Microgrid networks present a system-of-systems architecture comprised of autonomous entities and distributed built-in adaptive capacity that can be coordinated to achieve further benefits and enhanced resilience. A coalition constrained cooperative game-theoretic distributed algorithm is developed to coordinate resources between microgrids. Finally, we develop a new class of switching attacks that exploits existing system vulnerabilities using an adversary threat model with limited resources. The study emphasizes the importance of addressing existing vulnerabilities in the power system for an improved resilience.

Keywords: cybersecurity
distributed control/algorithm
energy storage
resilience
smart grid
stability
Advisor: Kundur, Deepa
MRI Characterization of Peripheral Arterial Disease for Planning Percutaneous Vascular Interventions

Peripheral arterial disease (PAD) is a common, chronic problem with significant morbidity and mortality. When PAD is severe, it is called “critical limb ischemia” and in this subset of patients up to 40% require a major amputation within just one year of diagnosis. Current treatment options involve revascularizing the leg through either bypass surgery or percutaneous vascular intervention (PVI). PVI offers a less invasive approach with improved morbidity and shorter length of hospital stay compared to surgery. However, PVI has high immediate technical failure rates (20%) and high re-intervention rates (~30%). The most common mode of immediate technical failure is the inability to enter or cross the target lesion due to the mechanical properties of the lesion. With current imaging, it is impossible to predict which lesions will be soft enough to cross with a wire to make PVI possible. This thesis addresses gaps in knowledge about how to appropriately select patients for PVI using novel imaging techniques. We have developed an MRI method using ultrashort echo time and steady state free precession flow-independent imaging that characterizes hard versus soft peripheral arterial lesion components and related those characteristics to ease of crossing during PVI. We performed ex-vivo studies using high-resolution MRI to define the signal behavior of individual lesion components and demonstrated high diagnostic accuracy by comparing images with microCT and histology. Further, we demonstrated that MRI signal behaviour could differentiate lesions that required high guidewire puncture forces from lesions that are easy to puncture. We translated this technique to a clinical protocol and validated images of amputated limbs with ex-vivo high-resolution MRI, microCT and histology. Finally, we imaged patients with the clinical protocol prior to their PVI, and demonstrated that MRI could identify lesions that took significantly longer to cross with a guidewire and required stenting more often. This thesis presents an original contribution to knowledge with the development and validation of a new MRI diagnostic test that can determine which peripheral arterial lesions are more difficult to cross with a guidewire. Future work will determine if MRI lesion characterization can predict long-term endovascular outcomes to aid procedure planning.

Keywords: chronic total occlusions
critical limb ischemia
endovascular
MRI
peripheral arterial disease
vascular imaging
Advisor: Wright, Graham A.
Dueck, Andrew D.
Maternal Leukocytes at the Uteroplacental Interface: Identification and Characterization of a Novel Decidual Neutrophil Population

INTRODUCTION: The uterine vasculature adapts during pregnancy to augment perfusion of the intervillous space by maternal blood, ensuring optimal fetomaternal exchange at the uteroplacental interface. Trophoblast invasion of the decidua and subsequent remodeling of the spiral arteries transforms the uterine vasculature into large bore, low resistance, high volume conduits which are unresponsive to maternal vasomotor control, thus maintaining increased blood flow to the fetus. KNOWLEDGE GAP: Leukocytes are found in abundance at the uteroplacental interface, and play important roles in regulating maternal tolerance to the fetus and spiral artery remodeling. However, little is known regarding second trimester decidual leukocyte populations and their function, including the role of neutrophils during this sensitive period of pregnancy. APPROACH: A comparison of first and second trimester decidual leukocyte populations was conducted to better understand normal and pathological uteroplacental development. The capacity of peripheral blood neutrophils to differentiate in response to decidua-secreted factors was assessed in normal and pathological pregnancy. RESULTS: This thesis documents: 1) changes in decidual immune cell populations from first to second trimester, including a shift towards tolerogenic phenotypes with advancing gestation, 2) the identification of a decidual neutrophil population appearing in late first trimester and continuing to increase into the second trimester, 3) the acquisition of a functionally angiogenic neutrophil phenotype expressing markers of both canonical N1 and immunosuppressive N2 neutrophils in peripheral blood neutrophils with exposure to decidua-secreted factors, and 4) the altered receptivity of neutrophils from preeclamptic women to decidua-induced differentiation. CONCLUSION: This work is the first to identify and analyze the decidual neutrophil population in healthy and preeclamptic pregnancy, and establishes a foundation for future study into the role of neutrophils at the uteroplacental interface.

Advisor: Lye, Stephen J