VictorJuiz/thesis huggingface dataset:
Carotid Magnetic Resonance Imaging Depicted Intraplaque Hemorrhage and a High-Risk Cardiovascular and Cerebrovascular Phenotype

Intraplaque hemorrhage is an independent marker of cardiovascular outcomes including stroke and myocardial infarction. Magnetic resonance imaging allows for the direct visualization of intraplaque hemorrhage in the vessel wall of the carotid arteries. This thesis reports data from an institutional magnetic resonance depicted intraplaque hemorrhage experience and clinical trials. The work herein addresses areas particularly sparse on the relationship of intraplaque hemorrhage with cardiovascular risk factors and its potential role in stroke, specifically reporting on i) age-specific sex differences in low-grade stenosis, ii) the role in ipsilateral embolic stroke of undetermined source, and iii) the relationship with a high-risk cardiovascular phenotype. The results in this thesis support our hypotheses that i) males have greater age-specific odds of magnetic resonance imaging depicted carotid intraplaque hemorrhage compared to females, and that with increasing age, the odds of carotid intraplaque hemorrhage in females becomes closer to that of males, ii) patients with embolic stroke of undetermined source have carotid intraplaque hemorrhage ipsilateral to the affected brain, and iii) patients with carotid intraplaque hemorrhage are of a high-cardiovascular risk. The culmination of projects supports the notion that intraplaque hemorrhage is related to a high-risk cardiovascular phenotype and a need for the quantification of intraplaque hemorrhage is realized to further understand the significance of volume of intraplaque hemorrhage, longitudinal changes in intraplaque hemorrhage over time, and relationship of intraplaque hemorrhage with clinical outcomes. The final project in this thesis therefore reports the development of a quantitative imaging analysis protocol, as well as its reliability and agreement with an established standard. The protocol is intended for use on carotid trial imaging data presently being acquired as part of the Canadian Atherosclerosis Imaging Network Project 1.

Keywords: Atherosclerosis
Carotid
Carotid stenosis
Intraplaque hemorrhage
MRI
Vessel wall imaging
Advisor: Moody, Alan R
Encapsulation-Free Local Delivery of BDNF Enhances Recovery in Stroke-Injured Rats

Until the early 1990s it was common belief that the adult brain did not possess the capacity to change or regenerate. We now know that the adult brain is not static and is able to repair itself to a small degree. Through examination of endogenous processes, brain-derived neurotrophic factor (BDNF) has emerged as a key modulator of plasticity in both the healthy and stroke-injured brains, and benefits to recovery have been demonstrated upon its administration; yet, current delivery strategies are highly invasive or inefficient. The work presented herein describes an effective, biomaterial-based strategy for minimally invasive local delivery of BDNF using a revolutionized approach to control protein release. BDNF incorporation into a composite consisting of poly(lactic-co-glycolic acid) (PLGA) nanoparticles and a hyaluronan and methyl cellulose (HAMC) hydrogel provided sustained release of the protein, using electrostatics to control release without encapsulation. When delivered epi-cortically to a rat endothelin-1 model of stroke injury, BDNF diffused from the HAMC/PLGA composite into the lesioned tissue and resulted in improved early forelimb recovery and delayed hindlimb performance enhancement. Tissue analysis revealed synaptic plasticity in the contralesional hemisphere at the time of sacrifice, suggesting that these behavioural effects were due to increased plasticity in the uninjured tissue. These studies validate the use of BDNF for plasticity-mediated stroke treatment and provide a minimally invasive strategy for effective, local delivery to the brain.

Keywords: BDNF
biomaterials
drug delivery
hydrogel
nanoparticle
stroke
Advisor: Shoichet, Molly S
Food for Empire: Wartime Food Politics on the Korean Homefront, 1937-1945

This research examines how the minute details of food production and consumption in colonial Korea became a target of wartime food politics under the rubric of improving productivity and efficiency for war efforts. In examining the politics, this research takes a more expansive approach to power and politics by locating the agency of power beyond the state and understanding its nature as more than simply totalitarian or suppressive. To this end, this study investigates the knowledge production of a group of experts—ranging from agronomists (Chapter 1 and 2) and nutritional scientists (Chapter 3 and 4), to cookbook authors (Chapter 4) and gardening manual writers (Chapter 5)—who, each in their own way, voiced opinions on the political, cultural, and social issues of the time beyond the sheer material concerns of enhancing productivity in food production and consumption. This research pays especially close attention to three recurring and entangled topics: first, the changing position of the colony and its population in the expanding empire; second, the geographical relationship between city and countryside in the urbanizing peninsula; and finally, ideal gender roles in the bourgeois domestic space. By attending to these themes through the lens of race, region, gender, and class, this study traces how a range of varied social aspirations betray tensions, dilemmas, and contractions of the time rather than converging in the fascist ideology for continuous improvement in total harmony, free from social conflicts.

Keywords: Colonialism
Everyday Life
Food History
Japanese Empire
Korean History
Total War
Advisor: Schmid, Andre
Developing and Coordinating Autonomous Agents for Efficient Electricity Markets

Whether for environmental, conservation, efficiency, or economic reasons, developing next generation electric power infrastructure is critical. Temporally relevant, granular data from smart meters provide new opportunities for data-driven management of the power grid. New developments—for example, electricity markets with multiple suppliers, the integration of renewable power sources into the system, and spikier demand patterns due to, say, electric vehicles—create new challenges for efficient grid operation. Computer science is uniquely positioned to assist with increasingly sophisticated techniques for handling and learning from large amounts of data. The methods of game theory and multi-agent systems provide a natural framework for modeling the competing incentives of electricity market participants. This thesis focuses on the use of learning, optimization, mechanism design, and preference elicitation methods to coordinate electricity demand and supply while respecting the incentives of market participants. Specifically, we propose an approach where an autonomous agent acts on behalf of each household, coordinating with inhabitants to relay information and make decisions on their behalf about electricity consumption. We focus on three problems that arise in developing such agents: (i) how to coordinate consumers' electricity use, (ii) how to share the costs of consumption among households (via their agents), and (iii) how to gather consumption preference data from consumers. Chapters 3 and 4 focus on different aspects of the first two problems. Both use a matching markets approach. In Chapter 3, we focus on the impact of demand smoothness and peaks on the supplier’s cost, and in Chapter 4, on the impact of predictability. In both chapters, we develop new cost sharing schemes that are resilient to certain forms of strategic behavior on the part of the agents and that achieve strong performance in experiments. Chapter 5 studies the third problem. Motivated by control of heating and cooling systems, we present a new approach to preference elicitation, where the cost and accuracy of query responses is dependent on the user’s familiarity with the conditions specified in the query. We show that despite the theoretical difficulty in this setting, we can build solvers that perform well in practice.

Keywords: cooperative games
energy
market design
Markov decision processes
preference elicitation
sequential decision-making
Advisor: Boutilier, Craig
Immanent Causation in Spinoza and Scholasticism

Spinoza is well-known for his claim that God is the only substance that exists, and that everything else is a mere “mode” of that substance. At the same time, Spinoza maintains that all things depend causally on God for their being. But if all of reality is in some sense identical with God, in what manner can God be its cause? Spinoza’s answer is found in his claim that “God is the immanent, and not the transeunt, cause of all things.” In this thesis, I investigate the scholastic roots of this distinction and its implications for understanding the fundamental features of Spinoza’s monistic ontology. The scholastics commonly distinguish between two kinds of activities, one which “remains” in the subject doing it and the other which “passes” outside. Those classified as immanent were primarily mental operations like thinking and willing. The first part of this thesis examines how the scholastics disagree over whether this kind of activity ought to be construed as a kind of production; the nature of its relation to its subject; and whether it is produced by means of ‘emanation’. The concept of an immanent cause emerges within this context. In the second part of this thesis, I bring this research to bear on our understanding of Spinoza’s metaphysics. First, I support the interpretation that Spinoza’s immanent cause emanates its effects within itself, in the manner that the properties of a thing follow from its essence. Contrary to what some scholars have suggested, however, this entails neither that it is a form of formal causation, nor that Spinoza’s conception of immanent causation is fundamentally discontinuous with the scholastic tradition. Second, I look at how Spinoza’s claim that an immanent cause undergoes what it does can be reconciled with the apparent impossibility of God undergoing anything on Spinoza’s system. I argue that we should distinguish between two senses of undergoing in Spinoza: God cannot undergo in the sense of being determined by external causes. But as the immanent cause of all things, God undergoes in the sense of being the thing that is affected by his own action.

Keywords: Causation
Immanent Causation
Metaphysics
Scholasticism
Spinoza
Suárez
Advisor: Pickavé, Martin
Rozemond, Marleen
Staging the Future: The Politics of Photographic Representation in Postsocialist China

This dissertation examines the changing nature of photographic representation in China from 1976 until the late 1990s, and argues that photography and photo criticism self-reflexively embodied the cultural politics of social and political liberalisation during this seminal period in Chinese history. Through a detailed examination of debates surrounding the limits of representation and intellectual liberalisation, this dissertation explores the history of social documentary, realist, and conceptual photography as a form of social critique. As a contribution to scholarly appraisals of the cultural politics of contemporary China, this dissertation aims to shed insight into the fraught and often contested politics of visuality which has characterized the evolution of photographic representation in the post-Mao period. The first chapter examines the politics of photographic representation in China from 1976 until 1982, and explores the politicisation of documentary realism as a means of promoting modernisation and reform. Chapter two traces the internationalisation of photographic theory and practice in China throughout the 1980s, while exploring the pervasive engagement among photo critics with issues of historical representation, national progress, and the role of the photography in representing social change. The third chapter examines the photographic oeuvre of Mo Yi from the mid 1980s to the late 1990s, and situates his work within the broader photographic and cultural politics of the period, while chapter four examines the history of conceptual photography and photo theory in China during the 1990s.

Keywords: Chinese cultural history
Chinese history
Chinese photography
Chinese politics
intellectual history
Advisor: Purtle, Jennifer
Identity, Subjectivity, and Schooling: Portugueseness and the Educational Deselection of Portuguese-speaking Students in Toronto

The academic trajectories of Portuguese-speaking students in Toronto, Canada, have been characterized as underachieving and truncated. Concurrently, the voices of Portuguese-speaking students themselves have been relatively absent from reports on their rates of underachievement and school dropout. This critical school ethnography explores Portuguese-speaking students’ school experiences in a Toronto high school to contextualize these statistics and expose how identity and subjectivity inform their school (dis)engagement. While peers and parents inform aspects of said (dis)engagement, thus far these have been the main if not only factors to explain this underachievement phenomenon. This ethnography, however, demonstrates that school personnel and their expectations appear to also play a role in some students’ decisions to deselect schooling. This dissertation exposes discourses that circulate in classrooms and other school spaces that construct Portuguese-speaking students and their parents in Toronto as working class immigrants. These discourses (inclusive of phrases and actions) draw on language, nationalism and diaspora, and class and labour to construct dominant depictions of what I and others (da Silva, 2012) have termed portugueseness. Portugueseness becomes a subjectivity that marks the Portuguese-speaking student subject for certain experiences in schools. In addition to reflecting on their experiences to illustrate how portugueseness is constructed, participants’ experiences and narratives revealed that association with portugueseness (or being marked as Portuguese(-speaking)) placed them disproportionately at risk of experiencing certain disciplinary practices in school. These disciplinary practices reference dominant depictions of portugueseness, namely disciplining language, dropout and disability. And, participants recounted both their defiant and compliant responses to these disciplining practices. Finally, disciplinary practices appear to inform educational deselection, a process that sees some students drop out of school and others remain enrolled despite deeply disengaging with school and putting forth a bare minimum of effort to be pushed through, rather than be pushed out of, their high school trajectory.

Keywords: ethnography
Portuguese
Portuguese-speaking youth
push-through
schooling
youth studies
Advisor: McCready, Lance T
Sociophonetic Variation and Change in Northern Ontario English Vowels

This thesis presents the first sociophonetic analysis of vowel variation and change in Temiskaming Shores (population 9,920) and Kirkland Lake (population 7,981), two small communities in northern Ontario. I compare the speech of these two communities to that of Toronto, Ontario, the largest and most linguistically diverse city in Canada (population 2,731,571), and Thunder Bay, Ontario (population 107,909), a smaller urban centre 950 km northwest of Temiskaming Shores and Kirkland Lake and 1400 km northwest of Toronto. I analyze four vowel variables: Canadian Raising, the phonologically conditioned raising of the onset of front upgliding and back upgliding diphthongs /aɪ/ (as in the word price) and /aʊ/ (as in mouth) before voiceless consonants, the merger of the low back vowels /ɑ/ (as in lot) and /ɔ/ (as in thought), the Canadian Shift, the retraction and lowering of the front lax vowels /ɪ/ (as in kit) and /ɛ/ (as in dress) and /æ/ (as in trap), and the fronting of the high back vowel /u/ (as in goose). The data for the project comprises over 52,000 tokens of Canadian English vowels in 11 vowel categories drawn from two large corpora of Canadian English and based on a speaker sample that is stratified by community, age, and sex. I use linear mixed-effects regression models fit to Lobanov-normalized F1 and F2 of each vowel token to analyze the influence of the social factors of community, sex, and age, as well as the linguistic factors of following and preceding phonetic context on each phonological variable. The main findings of the thesis are that despite some regional differences, the vowel systems of Kirkland Lake and Temiskaming Shores are essentially similar to those of Toronto and Thunder Bay, and that this underlying stability corroborates the longstanding claim of homogeneity of English across Canada.

Keywords: Canadian English
Language variation
Phonetics
Advisor: Tagliamonte, Sali A
Neurophysiological mechanisms underlying deep brain stimulation for the treatment of movement disorders

Deep brain stimulation (DBS) is an invasive neuromodulation therapy for management of the motor symptoms of several movement disorders; however, its mechanisms are complex, varied, and remain unclear. We employed a dual-microelectrode methodology for intraoperative measurement of neuronal activity and synaptic events, in order to assess the physiological response properties of different subcortical DBS target structures to electrical stimulation at different settings. A total of 50 patients with Parkinson’s disease undergoing DBS surgery of the subthalamic nucleus (STN; n=40), globus pallidus internus (GPi; n=8), or ventral intermediate nucleus (Vim; n=2); and nine patients with essential tremor undergoing DBS surgery of the Vim (n=9) participated in the studies. We found that the STN required higher frequencies for inhibition during stimulation compared to the substantia nigra par reticulata (SNr), likely due to a higher prevalence of GABAergic terminals on SNr somas; although both structures receive predominantly GABAergic inputs. In the Vim, a structure with predominantly glutamatergic synapses, higher (200Hz) frequencies were required for neuronal inhibition compared to the STN (100Hz) and SNr (50Hz). Additionally, unlike the STN and SNr, a transient period of neuronal excitation occurred prior to inhibition, reflective of the glutamatergic predominance. Thus, the effects of electrical stimulation are site specific and dependent on the weighted composition of inhibitory and excitatory inputs. We furthermore determined that an enhancement of inhibitory synaptic plasticity occurred in the SNr and GPi after continuous high frequency stimulation (HFS) at 100Hz; demonstrated by increased amplitudes of extracellular inhibitory field evoked potentials (fEPs). We found greater plasticity in the GPi compared to SNr, and that intraoperative administration of levodopa had a potent effect on SNr plasticity. Further, we determined that during stimulation at ≥30Hz, synaptic depression occurred in the SNr; demonstrated by rapid attenuation of successive fEPs. Clinically, we determined that lower levels of SNr plasticity were related to higher severity axial and global motor symptoms, and that neuronal inhibition in the Vim was necessary for tremor suppression. These findings expand upon the understanding of the physiological stimulation response properties of different brain structures in movement disorders patients, and may have implications for advancing DBS technologies.

Keywords: deep brain stimulation
essential tremor
neurophysiology
Parkinson's disease
synaptic plasticity
Advisor: Popovic, Milos R
Hutchison, William D
Game-Based Assessment of Cognitive Status in Clinical and Non-Clinical Samples

In this dissertation I validated a serious game for cognitive assessment that was originally developed in my Masters thesis (Tong, 2014). I used a whack-a-mole game that requires response inhibition, by adding a distractor character that should not be hit. I evaluated the game as a potential screening tool for the clinically relevant condition of delirium, and I examined how game performance was correlated with the Mini-Mental State Examination (MMSE), a standard assessment of cognitive ability in the elderly. Patients 65 years and older presenting at the Sunnybrook emergency department participated in three clinical studies and response time (RT) on the game was found to be significantly correlated with MMSE scores, and sufficiently predictive of whether the person had delirium as determined by the Confusion Assessment Method. Comparing game performance at 8-hour intervals, I found that game RT showed good test-retest reliability in the second clinical study. In the third clinical study, I found that false alarm rate provided a useful supplement to median correct RT in predicting clinical measures. Following the clinical studies, I evaluated the game with healthy adults in a pilot study to determine how the duration of character appearance affected whether the task was speeded or not. I found that a character appearance duration of around 800 msec marked the transition from a speeded to an unspeeded task. I then carried out a final experiment with healthy adults where the two appearance durations used were 800 msec (borderline speeded) and 1200 msec (unspeeded). The experiment assessed game performance for eight combinations of character appearance duration and two other dichotomous factors, and assessed performance on four tasks that measure different aspects of inhibition ability (Stroop task, Flanker task, anti-saccade task, Go/No-Go discrimination task). False alarms increased significantly in the condition where targets were least frequent and distractors were visually similar to the target. Game performance was strongly correlated with performance on the Go/No-Go discrimination task but not with the other three inhibition tasks used. The results of this thesis point the way towards the development of serious games that can supplement current clinical assessments.

Advisor: Chignell, Mark