VictorJuiz/thesis huggingface dataset:
Undergraduate Social Sciences Students' Attitudes Toward Statistics
Keywords: Attitudes
Social Sciences
Statistical Literacy
Undergraduates

This study investigated the changes in undergraduate social sciences students’ attitudes toward statistics in an introductory statistics course for social science students. The relationships between students’ attitudes toward statistics and their past mathematics achievement, their statistics outcomes, their sex, and their year of study were also investigated. The Survey of Attitudes Toward Statistics (SATS-36©) was used to collect data on students’ attitudes toward statistics. The study found no significant differences between male and female students’ attitudes toward statistics. Moreover, no significant differences in attitudes were found by year of study of the participants. By the end of their introductory statistics course, students’ attitudes improved for those students with low initial scores regarding their feelings concerning statistics, their competency in doing statistics, their valuing of the subject in their personal and professional lives, their perception of the difficulty of the subject, and their efforts to learn statistics. However, their interest in statistics remained the same. Students’ attitudes-scores dropped for those students with high initial responses regarding their competency to do statistics, their valuing of the subject, and their interest in statistics. Their feelings concerning statistics, their perception of the difficulty of the subject, and their effort to learn statistics remained the same. Students’ past mathematics achievement, their valuing of, and their effort to learn statistics predicted their statistics outcomes by the end of the course. Additionally, students’ interest in statistics predicted their effort to learn statistics and their valuing of the subject by the end of the course, which contributed to their statistics outcomes. The results also revealed that, students’ past mathematics achievement, and their perception of the difficulty of the subject predicted their cognitive competence in statistics, and their cognitive competence predicted their affect toward statistics by the end of the course.
Neural Representations of the Visual World Across Space and Time
Keywords: EEG
fMRI
Geometry
Object
Scene
Texture

A fundamental question of cognition and perception has asked how the human brain represents the local visual environment. Investigations seeking to answer this question have often explored the contributions of spatial information, such as geometry and layout, in forming a holistic percept of the visual world, yet a growing body of work suggests multiple properties may be crucial to the underlying neural mechanisms supporting scene recognition. This dissertation aims to examine the role of common and ubiquitous visual features, described here as geometry and surface properties, in shaping neural representations of the visual environment across space and time. Investigations in Chapter 2 sought to elucidate the weighting of geometry and surface properties in object and scene perception, and demonstrated equal sensitivity in the scene-selective parahippocampal place area for these features within a scene, and greater sensitivity to the surface information of an object, over its geometry. In Chapter 3, the interactions of these properties with goal-directed behaviour and higher-order scene attributes were examined, with results indicating that scene-selective cortex constructs a flexible representation of the visual environment by integrating diagnostic visual information with task context. Following this investigation, Chapter 4 examined these features within the temporal domain, wherein dissociable neural activity patterns emerged demonstrating how these features may diverge across time to influence the time course of scene perception. Together, these results demonstrate that multiple visual properties shape neural representations responsible for successful scene recognition, and these properties interact with goal-directed behaviour, and unfold across time, to influence our perception of the visual world.
Rapid cAMP signaling regulates the postsynaptic modification underlying synaptic plasticity and memory
Keywords: cAMP
FRET
LTP
Memory
Optogenetics
Synaptic plasticity

Understanding how synaptic structure and function is modulated by synaptic activity is essential for elucidating the mechanisms of learning/memory. Here I propose to elucidate a novel role for postsynaptic cyclic AMP (cAMP), a ubiquitous second messenger, in synaptic plasticity and learning by establishing novel cAMP optogenetic techniques. Strong synaptic activation such as LTP (long-term potentiation) or LTD (long-term depression), induce changes in postsynaptic structures (dendritic spines) in a process called structural potentiation. This process is crucial not only for activity-dependent synapse structural changes but also for functional plasticity such as LTP. We previously revealed that the major cytoskeletal protein actin interacts with the abundant postsynaptic enzyme CaMKIIβ (calcium/calmodulin-dependent protein kinase II β subunit), directly regulating dendritic spine structure during plasticity. Furthermore, we found that it also regulates LTP through the activity-dependent dissociation of the CaMKIIβ/actin complex. However, the detailed signalling pathway for regulating this mechanism during plasticity remains elusive. Pharmacological and genetic manipulation of the postsynaptic cAMP pathway revealed that cAMP signaling is essential for synaptic plasticity and memory. However the rapid spatial and temporal functions are not well known due to the lack of techniques to spatiotemporally control signaling activity. To address how postsynaptic cAMP regulates synaptic plasticity and memory, I established optogenetic approaches to spatiotemporally manipulate cAMP amounts by light from the single synapse to the brain region of freely moving mice. Utilizing this technique, combined with two-photon live imaging, electrophysiology, and mouse behavior assays, I demonstrated a novel role for postsynaptic cAMP modulating structural and functional synaptic plasticity and short-term learning. This proposed research, in particular, the non-invasive light-dependent manipulation of cAMP levels ex vivo, could also serve as valuable tools for elucidating the role of cAMP signalling in a broad variety of research fields.
Assessment of Peripheral Microcirculation using Magnetic Resonance Imaging
Keywords: Arterial Spin Labeling
Microvascular Dysfunction
Perfusion
Peripheral artery disease
Reactive Hyperemia
Revascularization

This thesis describes the development of a new measurement and analysis tool to assess the microcirculation in limb ischemia. Peripheral arterial disease (PAD) is diagnosed by reduced bulk blood flow and blood pressures in the legs. Patients with severe limb ischemia have limited walking ability and may experience rest pain or foot ulceration. PAD can be treated with revascularization for their large-vessel diseases. However, some patients respond poorly to revascularization. It is hypothesized that the microvascular disease component of limb ischemia may contribute to the differential outcome of revascularization. Therefore, this project is motivated to probe peripheral microvascular perfusion and to investigate the related vascular physiology and clinical indications of limb ischemia. A magnetic resonance imaging-based technique, called arterial spin labeling (ASL), was developed to characterize the dynamic perfusion response to brief periods of flow interruption. In a group of healthy subjects, the technique captured the changes of calf muscle reactive hyperemia with respect to the different durations of flow interruption, reflecting the microvascular function in regulating perfusion for different amounts of metabolic stresses. In addition, the technique also captured the differences between patients with PAD and healthy subjects in the dynamic characteristics of reactive hyperemic responses. Next, a quantitative physiological model, incorporating the influences of arterial stenoses and microvascular dysfunction, was established to facilitate the physiological interpretation of ASL reactive hyperemia. Model-derived perfusion indices were compared between subject groups. Patients were found to have higher arterial resistance and lower microvascular sensitivity to hypoxia than the healthy subject group. Finally, the perfusion measures were compared with symptom severity and functional outcome 6-month following successful endovascular revascularization in a cohort of patients. Measures of arterial resistance were related to the manifested severity, whereas the microvascular sensitivity index appeared to differentiate prognosis following revascularization. Overall, this thesis improved the ASL method to assess peripheral muscle perfusion and demonstrated the clinical relevance of perfusion measures to symptom severity and revascularization outcome of PAD for the first time. A future study with a larger patient population and longer follow-up period will be required to confirm the current findings.
Decolonizing Narratives:Kittitian Women, Knowledge Production and Protest
Keywords: decolonization
feminism
indigenous knowledge
liberation
oomanism
womanism

Abstract The thesis acknowledges how women contest domination and challenge us to re-examine the subjects of our history. It centers the stories of 21 African women, who remember a popular uprising in St. Kitts in 1935. Their stories explore how these embodied narrators reconstruct a defining moment in the islandâ s history for insertion into the gaping holes of history that had been left for the imagination, conjecture, and a hegemonic discursive shaped by archival records. Their stories are worth remembering, demand examining and not just to be recorded for posterity. They must be accorded equal value as academic knowledge. The use of storytelling as a methodological approach introduces the Kittitian language to text, removes the burden of colonized linguistic syntax and grounds the epistemological context of the findings and analysis. It provides new evidence of the invasiveness of coloniality and how it interlocks with Caribbean rebel consciousness to usurp decolonial exertions, discursively and institutionally. The work does not claim to provide a representative sample of the hundreds of protestors in 1935, nor do the women speak for all the citizens who were impacted by the social unrest. It questions the processes that normalize the silencing of valuable knowledge that can only be found in the language and memories of subjugated populations. Finally, this study reconstitutes the tellers as knowledge producers, decolonizes their womanhood, and depathologizes the resistance movement. It focuses on how these culture bearers remember the protest and how they reconstruct themselves in relation to the historical event and how they reconstitute their subjectivities through their understanding of what the protest meant for themselves, their families, and communities. The study has implications for further research and knowledge production designed to decolonize Caribbean histories, to accelerate the process of healing the psychological scars and other residual effects of colonization and attests to the resilience of cultural memory. Keywords: Caribbean cultural forms, womanism, feminism, indigenous research, decolonization, liberation, knowledge production, historiography, social justice education
Developing and using a head-mounted miniature microscope to investigate memory formation in a mouse model of Alzheimer's Disease
Keywords: Alzheimer's Disease
Calcium imaging
Fear conditioning
Hippocampus
Memory
Pattern completion

Alzheimer's Disease (AD) is characterized by progressive memory loss. Results from many experiments suggest AD begins as a disease of synaptic dysfunction. However, how synaptic dysfunction translates into circuit dysfunction and, ultimately, memory impairment is entirely unknown. To address the circuit-level dysfunction in AD, I developed a miniature fluorescent microscope that can be mounted on the head of a behaving mouse. We showed this mini-microscope is capable of imaging hundreds of neurons in the CA1 region of the hippocampus, and with minor modifications, also in deeper brain structures and in two colour channels. To investigate the circuit dysfunction in AD, we used transgenic mice designed to model AD in humans. These TgCRND8 mice (referred to as AD mice) express human familial AD genes and similarly develop memory impairments. As expected, we showed that AD mice have robust memory deficits in a contextual fear conditioning paradigm, in which mice were trained to associate an aversive stimulus with a context. Imaging data from our mini-microscope showed that compared to control mice, CA1 cells in AD mice were hyperexcitable and contained less information related to memory recall. Moreover, cells from AD mice showed a deficit in coordinated activity, suggesting that these mice are impaired in pattern completion, a process important in recalling hippocampal-dependent memories. Previous studies suggest that AD mice have excessive endocytosis of GluA2-containing AMPAR, which accounts for their synaptic dysfunction. We found disrupting GluA2 endocytosis using an interfering peptide (TAT-GluA2\textsubscript{3Y}) before training was sufficient to rescue the memory and circuitry deficits in AD mice. Moreover, we showed disrupting GluA2 endocytosis during a reminder three days after training also restored memory. These results argue that AD mice still retain some aspect of the memory days after training, and that strengthening this weakened memory allowed mice to recall it. In conclusion, I developed and used a novel calcium imaging method to investigate the circuit dysfunction in a mouse model of AD. Using this tool, I revealed an important link between the synaptic and circuit deficits in AD mice. These findings may have important implications for designing the next generation of tools and therapies for AD.
Identification and Characterization of Novel Upstream Regulators of the Hippo Signalling Pathway
Keywords: Cancer Biology
Hippo Pathway
Signal Transduction
YAP/TAZ

The evolutionarily conserved Hippo signalling pathway is a major determinant of growth control and organ size. The co-transcription factors YAP/TAZ are downstream effectors of the Hippo pathway that regulate vital processes like cell proliferation, cell migration, apoptosis, stem cell self-renewal and differentiation. YAP/TAZ are regulated by the core Ser/Thr kinases of the Hippo pathway MST1/2 and LATS1/2. Upon activation, MST1/2 in association with the adaptor protein SAV, phosphorylate and activate the downstream kinases LATS1/2. In turn, activated LATS1/2 in association with the adaptor protein MOB, phosphorylate YAP/TAZ leading to cytoplasmic accumulation, degradation and transcriptional inactivation of YAP/TAZ. The Hippo pathway can be regulated by various intrinsic and extrinsic stimuli such as mechanotransduction, actin cytoskeleton dynamics, cell-cell contact and cell polarity, G-protein coupled receptor signalling and metabolic pathways. However, the mechanistic details and molecular mediators that connect the upstream stimuli to the core of the pathway are not fully understood. With the aim of identifying novel upstream regulators of the Hippo pathway we undertook a high-throughput LUMIER-based protein interaction screen complemented with a TEAD-luciferase reporter screen that led to the identification of βPIX and MARKs as positive and negative regulators of the Hippo pathway, respectively. Mechanistically, βPIX mediates the interaction between YAP/TAZ and the Hippo core kinase LATS to promote YAP/TAZ phosphorylation and transcriptional inhibition. Conversely, MARK4 enhances YAP/TAZ transcriptional activity in a kinase-dependent manner by phosphorylating MST and SAV, and disrupting complex formation with the downstream LATS kinase. Furthermore, abrogation of MARK4 or βPIX overexpression in breast cancer cells attenuates tumorigenic features such as proliferation and migration by activating the Hippo kinase cascade. Finally, βPIX and MARK binding partners GIT1 and DLG5 are respectively characterized as positive and negative regulators of YAP/TAZ transcriptional activity.
Administrative Justice: Guiding Caseworker Discretion
Keywords: discretion
new public management
regulatory technology
street-level bureaucrats
welfare

This thesis demonstrates how flexibility and constraint arise in the context of Ontario Works, a welfare program with a reputation as both rule-bound and discretion-rich. Based on a qualitative socio-legal study of front-line decision-making in five local offices across two southern Ontario municipalities, this dissertation explores how discretion functions at and behind the front-lines of the Ontario Works program. Drawing on legal and socio-legal literature, it demonstrates how in a formal sense discretion becomes explicitly and tacitly incorporated within discrete legislative provisions and, as these rules cross-reference one another, nested throughout an entire legal framework. Further, it shows how front-line workers animate these text-based grants as they perform operational discretion in their routine interactions with benefits recipients, such that it becomes virtually impossible to distinguish discretion from non-discretion at any specific decision-making moment. This thesis then shifts gears to argue that operational discretion is nonetheless guided by two factors: a shared methodology of normative balancing according to which workers reconcile competing legal and managerial norms; and a systematic diffusion of decision-making responsibilities among human and non-human actors such that decisions are produced and influenced by an aggregation of decision-makers. In doing so, it demonstrates how the effects of ideological divergence among caseworkers, on a spectrum ranging from pro-client social workers to black-and-white efficiency engineers, is minimized by the convergence prompted by normative balancing and aggregated decision-making. This thesis then reflects on how new regulatory technologies may subtly shift front-line workersâ perception of their roles as legal decision-makers, from caseworkers who perform discretion in relation to an audience of coworkers with whom they can reason to individuals who must covertly â manipulateâ the legal-technical system with which they are now governed.
Three Essays in Industrial Organization
Keywords: Competition
Industrial Organization
Regulation

This thesis contains three papers that empirically examine firm competition and market regulation in oligopoly settings. Chapter 1 looks at the effects of consumer search costs on entry, product design, and quality in online markets. Using data from the Google Play mobile app store, I take advantage of a natural experiment that reduced search costs for one product type (game apps) in early 2014. DiD estimates show that entry increased by 33$\%$ relative to the control group (non-games), primarily by ``niche" products. These estimates also show that the quality of new entrants fell. To separate out the different welfare effects of this change, I develop and estimate a structural model of demand and supply. I show that there are large welfare gains from reduced search costs, smaller gains from increased product variety, and very small losses from lower product quality. Chapter 2 (joint with Scott Orr and Jean-William P. Lalibert\'e) examines merger analysis in markets where products are demand complements. Standard discrete choice models assume that product varieties are substitutes. These models will overstate consumer harm in merger cases with complements. We use consumer level data to look at products with natural demand complementarity - chips and soda. We estimate a discrete choice model that allows for demand complementarity and simulate a merger between PepsiCo/Frito-Lay and Dr. Pepper. Our model predicts that pop prices either increase or fall in this merger. By contrast, the standard model predicts that pop prices would always increase. Chapter 3 (joint with Victor Aguirregabiria and Junichi Suzuki) studies the impact of competition in the Ontario wine retail market. The wine retail market of Ontario is characterized by the coexistence of the government-owned LCBO and two private companies. These private firms are restricted in their locations and their product variety. We estimate a spatial demand model using a unique dataset from the LCBO. We then simulate the effects of deregulation proposals (relative to a LCBO monopoly). We show that entry of additional competitors increases consumer welfare and consumption. Expanding the product range of existing competitors also increases consumer welfare, but keeps consumption stable.
Copyright and Freedom of Expression: A Rawlsian Charter Analysis
Keywords: Canada
Charter
Copyright
Expression
Proportionality
Rawls

This thesis considers the relationship between copyright and freedom of expression in the Canadian legal context. It is argued that the existing Copyright Act constitutes an unjustified limitation of the Charter right to freedom of expression. In addition to analyzing and applying the relevant case law, the thesis suggests an alternative conceptual framework for assessing Charter rights violations. The proposed framework is derived from John Rawls's political philosophy, and requires judges to reason as though behind a Rawlsian veil of ignorance. It is argued that the Copyright Act limits freedom of expression, since most copyright infringing acts are attempts to convey meaning. It is further argued that the limitation cannot be justified under section 1 of the Charter, as the Act would not be selected over the available alternatives while under the veil of ignorance.
Filling in the gaps of the spectrum-wide characterization of hydrophobins: An interface-active protein family with industrial potential
Keywords: Amyloid
Hydrophobin
SC3
Self-assembling

Hydrophobins are secreted non-catalytic fungal proteins that act at interfaces whose functions range from self-assembling to form a fungal â raincoatâ on the fruiting body, to recruiting enzyme activities to surfaces. Traditionally subdivided into two classes (I and II) based on primary sequence and observed solution characteristics, the underlying thesis of this work is that classification of type I hydrophobins can be further refined. As such, the analysis of the predicted primary sequences of hydrophobins originating from the genomes of over 200 fungal species was conducted by sequence-alignment principal component analysis (SA-PCA) revealing a high-identity class I Basidiomycota subdivision. To experimentally validate this subdivision, the structure of one of its members, the predicted Schizophyllum commune hydrophobin SC16 (hyd1), was solved by solution-NMR. While sharing the core hydrophobin structure, structural elements believed to be necessary for class I behaviour were absent. However, the protein was an active class I hydrophobin as demonstrated by specific binding to the amyloid-detecting dye Thioflavin T and rodlet formation at the air-water interface visualized by atomic force microscopy (AFM). Together, these results reveal a structural basis for the class IB subdivision. Next, methods to further characterize the spectrum of hydrophobin sequences were explored. Pichia pastoris was found to be an effective host for the soluble recombinant expression of the three predicted hydrophobins of the Ascomycota entomopathogen Cordyceps militaris genome. Of these solubly expressed proteins, the preliminary visualization of class I type rodlets by AFM of one of the three (CMil3) is discussed. In the final chapter the matrix-free chromatographic technique of flow field-flow fractionation was harnessed to study the oligomeric solution-state of hydrophobins. This dissertation concludes with next steps in applying the framework used for the sequence analyses as a means of mapping and testing the bounds of the unique properties exhibited by this protein family.