VictorJuiz/thesis huggingface dataset:
Who's Zooming Who
Keywords: Artistic Practices
Covid-19 Pandemic
Radical Feminist Care
Surrealism
Zoom Application

This thesis examines playwright Deb Margolin’s (2007) play O Yes I Will (I will remember the spirit and texture of this conversation) and her radical feminist approach of care in contrast to the chance-based operations utilized by surrealists John Cage, Andre Breton and Joseph Cornell. Ten disparate individuals perform selected dialogue through their experiential engagement with Margolin’s play via the application Zoom. Zoom's meta format is compared to surrealist interventions against a dearth of physical human interaction across the SARS-CoV-2's global backdrop of disenfranchisement. Margolin’s work reconsiders chance-based operations, reformulating this methodology into change-based practice, demonstrating how theatrical engagement with a one-woman show through this divergent group of people encourages healing and compassion.
The Impact of Fan-type Rapid Palatal Expanders on Speech in Patients with Unilateral Cleft Lip and Palate
Keywords: cleft lip and palate
palatal expander
speech

Fan-type rapid palatal expanders (RPEs) can affect tongue movement and speech because of their position and size. The present study investigated the effects on the speech of 25 patients with unilateral cleft lip and palate. Speech questionnaires (patients and parents) and standardized speech recordings (patients) were analyzed prospectively for psychosocial burden, vowel space, fricative articulation, and oral-nasal balance before insertion, after insertion, during expansion, during retention, after removal, and at 3-months follow-up after removal. RPE insertion resulted in an increase in dysfunction and distress, no change for the vowel /a/, an increase in the first formant for the vowel /i/ with a decrease in the second formant for the vowels /i/ and /u/, a decrease in the spectral means for the fricatives /s/, /ʃ/, and /z/, as well as no change in nasalance. All measures returned to baseline levels before removal. Speech was adversely, albeit transiently, affected by an RPE.
Patterns and Predictors of Growth in English Language Learners’ Vocabulary, Word Reading and Non-word Reading Fluency: A Longitudinal Perspective
Keywords: ELL
English Language Learner
Non-word Reading Fluency
Vocabulary
Word Reading Fluency

This study modeled vocabulary, word, and non-word reading fluency trajectories in 260 English Language Learners (ELL) from Mandarin, Cantonese, Portuguese, and Spanish home-language backgrounds from Grades 1-4. Longitudinal relations between early phonological awareness (PA) and rapid automatized naming (RAN) and the growth trajectories of the outcome variables were examined. Multilevel modeling revealed quadratic trajectories for all outcome variables, with differences in growth rates between language groups on vocabulary and word reading fluency, but not for non-word reading fluency. Regardless of home language, those with lower Grade 1 vocabulary and/or word reading fluency caught up to their ELL peers by Grade 4, but those with low non-word reading fluency did not. Grade 1 PA was the best predictor of growth in vocabulary, and Grade 1 RAN was the best predictor of growth in word and non-word reading fluency. Results are discussed in terms of implications for early identification and intervention.
High Stiffness Glass Flake Reinforced Composites Produced using Inverted Stereolithography
Keywords: Additive Manufacturing
Composites
Glass Flakes
Inverted Stereolithography

High aspect ratio glass flakes were introduced as the composite reinforcement in inverted stereolithography (ISLA). Due to flow-induced fiber alignment transverse to the intended loading direction, past attempts to produce high modulus composites by reinforcing the matrix with short fibers failed. Flake reinforced composites, however, reinforce the composite in all directions in the plane. Flake reinforced composites were successfully produced with good planar alignment and exhibited increasing elastic moduli and toughness with increasing flake volume fraction. Despite these promising results, viscosity limited the range of flake loading severely. The tradeoff between flake aspect ratio and the reinforcement efficiency was investigated by grinding flakes. Higher volume fractions of ground flakes were incorporated into the matrix.In summary, the results presented in this work show that adding flakes to the resin in ISLA may create a new path for the production of high performing, stiff composites using 3D printing.
About Explicit Variance Minimization: Training Neural Networks for Medical Imaging with Limited Data Annotations
Keywords: Artificial Neural Nets
Bias-variance Trade-off
Deep Neural Networks
Generalization
Medical Imaging

We proposed the Variance Aware Training (VAT), the novel method of training well-generalized Deep Neural Networks with limited data annotations. Our method requires selecting only one hyper-parameter and matching or improving the performance of state-of-the-art self-supervised methods while achieving an order of magnitude reduction in the GPU training time. We validated VAT on three medical imaging datasets from diverse domains and for various learning objectives and compared VAT with state-of-the-art self-supervised methods. These included a Magnetic Resonance Imaging (MRI) dataset for the heart semantic segmentation (MICCAI 2017 ACDC challenge), fundus photography dataset for ordinary regression of diabetic retinopathy progression (Kaggle 2019 APTOS Blindness Detection challenge), and classification of histopathologic scans of lymph node sections (PatchCamelyon dataset). Our code is available at https://github.com/DmitriiShubin/Variance-Aware-Training.
Neurophysiological Features of Working Memory Performance and their Relationships with Demographic, Clinical, Genetic, Neurochemical, and Neuro-structural Characteristics in Older Adults at Risk for Dementia
Keywords: Alzheimer's
Cognitive Reserve
EEG
Mild Cognitive Impairment
Theta-gamma coupling
Working Memory

Theta gamma coupling (TGC) is a neurophysiological mechanism of working memory (WM). However, the relative contributions of TGC and clinical, demographic, and biological characteristics to WM performance, and the relationship between TGC and these characteristics, remains unclear. Older participants at-risk for Alzheimer’s dementia completed N-back-EEG, genetic testing, PET scan and brain MRI. Linear regressions were used to assess the relationships among 2-back WM performance; demographic and clinical variables; TGC; ApoE4 carrier status; β-amyloid SUVR; and regional cortical thickness, subcortical volumes, and white matter fractional anisotropy. Our results demonstrate that TGC and age are strongly associated with 2-back WM performance. Analyses with additional WM features- theta event-related synchronization (ERS) and alpha event-related desynchronization (ERD)- revealed that neither theta ERS nor alpha ERD were associated with WM performance or any other characteristics. Our findings underline the strong association between WM and TGC, which may represent a mechanism of cognitive reserve.
Automation of Real-time Three-dimensional Image-based Visual Servo Control for Single Cell Surgery
Keywords: automated manipulation
embryo manipulation
image segmentation
micromanipulation
single cell surgery
visual control

Micromanipulation of biological cells is a challenging task that requires levels of precision and repeatability which are difficult to achieve by most human operators. Automation of these processes presents an alternative approach which is capable of high precision task execution and much higher throughput, yet with its own limitations. In this thesis, we propose automation methods for the image-based visual servo control feedback and tracking of both blastomeres’ motion and the motion of micromanipulators, in real-time, for blastomere micromanipulation. An automation procedure is developed for the microinjection or blastomere biopsy of an embryonic cell. These steps involve blastomere Z-stack image acquisition, 3D image processing to identify blastomere feature (X, Y, Z) coordinates, and real-time image-based visual servo control of micropipettes to hold and immobilize the embryo while a micropipette injects or biopsies the target blastomere.
Variational Autoencoders for Volatility Surfaces
Keywords: Quantitative Finance
Variational Autoencoders
Volatility Surfaces

The implied volatility surface is an important tool used by financial practitioners. It shows how the market price of an option varies as a function of its strike price and maturity. It conveys important information about market conditions and is typically used for risk management or as an input to exotic option pricing models. However, market data is sparse and incomplete, requiring trading desks to infer unobserved prices. Conventional methods used to complete volatility surfaces are often not flexible enough to adapt to rapidly evolving markets. This thesis demonstrates how variational autoencoders (VAEs) can be used to model volatility surfaces. We show how VAEs provide a flexible and entirely data-driven approach which is both computationally faster and conceptually simpler than traditional methods. We illustrate how VAEs can complete, explore, and generate synthetic volatility surfaces. Our methodology is demonstrated using S 500 index and foreign exchange options.
The Impact of Frailty on Outcomes after Spine Surgery
Keywords: aging
degenerative spine disease
elderly
frailty
outcomes
spine surgery

Background: It remains unclear how best to treat elderly patients with spinal pathologies. Aim: The aim of this thesis was to investigate the impact of frailty on outcomes after spine surgery. Methods: A systematic review on frailty and spine surgery was done. A study investigating the impact of frailty on morbidity in patients treated for degenerative lumbar spondylolisthesis was performed. The National Surgical Quality Improvement Program (NSQIP) database was used for this study. The primary outcome was major complications. Results: Thirty-two studies were included in the systematic review. Regardless of how frailty was measured, frailty was associated with an increased risk of morbidity and mortality. There were 15 648 patients in the study on patients treated for degenerative lumbar spondylolisthesis. Frailty was significantly associated with increased risk of morbidity. Conclusion: There is strong evidence that frailty is an independent predictor of morbidity and mortality after spine surgery.
Disentangling the Influence of Blood on Brain Parametric Maps and Volumetry
Keywords: Brain Imaging
Caffeine
Cerebral Blood Flow
Hemodynamics
MRI
Quantitative MRI

Caffeine, the most commonly used psychoactive substance in the world, leads to changes in cerebral blood flow (CBF). Recent research has shown that changes in CBF can bias regional estimates of brain volume and cortical thickness as measured by magnetic resonance imaging (MRI). In addition, recent studies have shown that quantitative MRI parameters that are indicative of tissue microstructure (T1, R2* and QSM) may also be sensitive to acute CBF changes. Here, we used an ecologically valid manipulation of CBF (caffeinated vs decaffeinated coffee) to assess whether our estimates of brain volume and qMRI maps are sensitive to caffeine-induced changes in CBF, in moderate caffeine users. Furthermore, an improved method for multi-parametric mapping was proposed and assessed in this study. As expected, CBF was significantly reduced after caffeine, however of all structural metrics explored, only R2* maps were sensitive to changes in CBF in this preliminary dataset of 5 subjects.
A Multimodal Assessment of Adults with Dravet Syndrome
Keywords: accelerated aging
adults
Dravet syndrome
gait
natural history
parkinsonism

Dravet Syndrome (DS) is treated as a developmental and epileptic encephalopathy. Several comorbidities in DS exist such as motor and cognitive abnormalities. Aging is not well characterized in these patients, and parents complain about their adult children losing previously acquired skills. We aimed to identify if DS adults experience a premature aging process. A systematic review was performed to characterize the adult phenotype. In our first study, we performed an instrumental gait analysis and evaluation of parkinsonisms. In our second study, we assessed gait, parkinsonisms, adaptive behaviours, screening for autism, and other clinical factors in a larger cohort. The review identified a 1:7 ratio of adult to children studies exclusively, and a lack of overall clinical adult studies. We identified worsening of physical and adaptive behaviours with age in our studies. Our studies show a progressive deterioration of most clinical manifestations, in keeping with an accelerated ageing process. A holistic approach to care is necessary in DS.
The Effect of Virion-Incorporated Host Proteins on the Expression and Conformation of the HIV-1 Envelope Protein
Keywords: Envelope glycoprotein
HIV-1
Virion-incorporated host proteins

The envelope (Env) glycoprotein of human immunodeficiency virus type 1 (HIV-1) is the sole target for the development of an HIV-1 vaccine. However, due to the extensive glycosylation and the metastable nature of Env, targeting the viral Env glycoprotein is very challenging. Recently, several host proteins have been described to be incorporated on the viral surface and to alter the course of HIV-1 infection, suggesting virion-incorporated host proteins could be a potential target for therapeutics and vaccine development. This thesis examined the impact of a panel of virion-incorporated host proteins on the infectivity of HIV-1. Our results showed that the incorporation of host proteins, CD162 and α4β7, significantly decreased the infectivity of HIV- 1. Furthermore, we found that virion-incorporated host proteins can alter the conformation of Env and affect the amount of Env incorporated onto the surface of viral particles. Taken together, our work shows that selected virion-incorporated host proteins can have an impact on the infectivity of HIV-1 and defining the effects of host proteins on the viral Env glycoprotein could be useful for designing new antiviral strategies.
Mathematical Modelling of Rodent Circadian Rhythms Involving Photic and Non-photic Inputs
Keywords: circadian pacemaker
food anticipatory activity
Kuramoto oscillators
parameter estimation
phase response curve
phenomenological model

We develop models that describe the effects of photic and food input on the mouse and rodent respectively. In the former, we construct a similar model to the Kronauer model. We fit the parameters to mouse phase response curve data. We deduce model parameter ranges using sensitivity analysis and parameter distributions. Applications of the model indicate the relation between parameter choice and aspects of rhythm generation/control. In the latter, we employ a population of Kuramoto oscillators to describe food anticipatory activity (FAA). The model captures the main features of FAA, such as multiple meals and meals of different periodicities. We explore the model by conducting a continuum approximation of the oscillators using the Ott-Antonsen ansatz. Finally, we suggest some interesting experiments that reveal important properties about the characteristics of FAA. The models developed provide insight and testable predictions to further our understanding of various circadian processes.
Application of the NewSpace and Microspace Philosophies to Small Satellite Constellation Development
Keywords: constellation
Microspace
NewSpace
satellite
SFL
smallsat

Through improvements in terrestrial technology and reduced launch costs, small satellites have seen a steady rise in popularity. Organizations like the Space Flight Laboratory utilize the Microspace approach towards satellite development, pushing the envelope and constantly expanding small satellite capabilities. However, for large constellation missions, the NewSpace approach may offer the greater benefit, focusing on manufacturing cadence and cost reduction. This thesis aims to demonstrate how the NewSpace and Microspace philosophies can be applied to the development of small satellite constellation missions. For a new single satellite mission, mechanical modifications were made to the DEFIANT platform, which drove changes to the bus layout of components and thermal design. Qualification vibration and thermal vacuum testing was completed to certify the SPARTAN bus for a commercial constellation mission. Lastly, for a DEFIANT cluster mission, the quality assurance, assembly, and integration processes were analyzed in the context of the NewSpace and Microspace philosophies.
Involvement of the Endosomal-lysosomal System in the Processing of Disease-associated Tau in Alzheimer’s Disease and Corticobasal Degeneration
Keywords: Alzheimer's disease
Cathepsin
Corticobasal degeneration
Lysosomes
Neurodegenerative disease
Tau

The microtubule-associated protein tau pathologically aggregates in multiple neurodegenerative diseases. In neurons, tau matures from pre-aggregates into neurofibrillary tangles (NFTs) in Alzheimer’s disease (AD). In corticobasal degeneration (CBD) only dot-like intracytoplasmic aggregates of tau are seen. The endosomal-lysosomal system (ELS) has been examined in relation to Amyloid-beta processing in AD, however, there is a paucity of data on the role of the ELS in the processing of tau. Therefore, we performed a neuron-specific double-immunolabeling morphometric study to evaluate the lysosomal enzyme cathepsin D and its relation to different cellular deposits of disease-associated tau (AT8) in AD and CBD. The area density of cathepsin D immunoreactivity levels showed significant decrease in all types of tau aggregates in AD but not in CBD. AT8 and cathepsin D colocalized significantly more in CBD compared to AD. Our results indicate a differential response of the ELS to tau accumulation in AD and CBD.
Estimation of Chloramine Decay in Drinking Water Distribution Systems
Keywords: chloramine decay
drinking water
drinking water distribution
pipe section reactor
secondary disinfection

Development of a means to identify and predict factors associated with chloramine decay in drinking water distribution systems could assist in providing targeted operational strategies which ensure regulatory compliance and ultimately lead to major cost-savings. In this study, novel bench-scale pipe section reactors (PSRs) were utilized to evaluate the impact of source water (surface or groundwater), pipe material, pipe age, and flow velocity on chloramine decay in a distribution system in the Greater Toronto Area, Ontario, Canada. Batch tests in amber glass bottles quantified decay in treated water which were compared to low- and high-flow PSR experiments to elucidate the impact of water velocity and pipe material on monochloramine decay. Of the factors examined, pipe material and condition (e.g., old or new) were identified as the most critical. Overall, the results of this study reinforce the importance of determining the source of residual disinfectant decay when considering chloramination.
Global Minimizers of the Interaction Energy and the Behaviour of Nearby Solutions to the Aggregation Equation
Keywords: Aggregation
Energy Methods
Optimal Transportation

Over the past decade, the aggregation equation has become a popular area of research within mathematics. While much of this interest has been driven by the equation's scientific applications, the equation also raises significant mathematical questions. Notably, we associate an interaction energy to the equation, with the property that global and local minimizers of this energy correspond to steady states of the aggregation equation. In this thesis, we partially classify global energy minimizers, when working with the aggregation equation endowed with a specific class of `power-law' potentials. We then explain this partial classification, as well as its limitations. After this, we follow in the footsteps of a recent PhD thesis to query the dynamics of solutions to the aggregation equation and, in particular, the behaviour of solutions which begin `close to' a global minimizer of the interaction energy. In doing so, we outline a promising future avenue of research.
Threat, Deprivation, and Executive Functioning in Childhood and Adolescence: A Meta-Analysis
Keywords: Adversity
Deprivation
Executive Function
Meta-Analysis
Systematic Review
Threat

To determine if threat and deprivation are differentially related to EF among children and adolescents, levels of EF among children exposed to adversity were compared to children not exposed. Articles from peer-reviewed journals through December 2020 were identified through multiple databases. A three-level meta-analytic model was used. Outcomes included measures indexing cognitive flexibility, inhibitory control, and working memory. Analyses were conducted on 91 articles, representing 82 unique cohorts, and 31,188 individuals. Deprivation, compared to threat, was associated with significantly lower inhibitory control and working memory. The pooled effect of deprivation on inhibitory control was g = -0.43 (-0.57, -0.29), and on working memory was g = -0.54 (-0.75, -0.33). The pooled effect of threat on inhibitory control was g = -0.27 (-0.46, -0.08) and on working memory was g = -0.28 (-0.51, -0.05). Efforts to address the effects of early-life adversity should consider differences in the type of adversity experienced.
Screening for Distress the 6th Vital Sign and Health Outcomes in Patients with Cancer
Keywords: Distress
Oncology
Psychosocial
Screening
Suicide

Screening for distress has become a standard-of-care in oncology globally, yet evidence of its impact beyond clinical trials is limited. The aim of this thesis was to elucidate the impact of distress screening on health outcomes in a real-world oncology setting. We tested the hypothesis that distress screening improves health outcomes through two studies that examined the association between (1) suicide risk screening (SRS) and suicide outcomes; and (2) distress screening, receipt of supportive care, and cancer-related survival. We found that completion of SRS was associated with fewer suicides, but this was not attributable to SRS response. Completion of distress screening was associated with higher cancer-related survival, partially mediated by early palliative care in advanced cancer. This thesis provides real-world evidence of the association between completion of distress screening and better health outcomes in cancer, while raising new research directions about the mechanisms underlying this relationship.
Improving the Magnetic Resonance Characterization of Cardiac Infarct Heterogeneity with Non-Cartesian Gradients
Keywords: 3D cones MRI
Cardiac MRI
CMR
Non-Cartesian
Stack of spirals
Ventricular Tachycardia

Sudden cardiac death is among the global leading causes of death and is most often caused by ventricular tachycardia where areas of heterogeneous infarct can decouple the cardiac cycle from its natural rhythm. Treatment for ventricular tachycardia can involve catheter ablation procedures which may be made more effective by obtaining high resolution scar maps via cardiac MRI. Currently, Cartesian imaging is the standard for cardiac MRI but the resolution and coverage obtainable using Cartesian techniques is limited by long acquisition times. This thesis addresses the use of non-Cartesian k-space trajectories which reduce scan times while increasing coverage and resolution. First, the efficiency benefits of non-Cartesian sequences are explored. Then, non-Cartesian images are presented and the image quality is validated against standard Cartesian images. The thesis ends with a discussion of how non-Cartesian trajectories can be further applied in different ways to improve the state of cardiac scar mapping with MRI.