VictorJuiz/thesis huggingface dataset:
Time Response Simulation for Nose Landing Gear Shimmy Damper Design

This thesis evaluates the effect of two structural modifications to the performance of the landing gear shimmy damper developed by Safran Landing Systems. The dynamic model that features the two structural modifications was developed with necessary adjustments and validations. The effects are evaluated based on both eigen-value based steady-state stability analysis and the maximum amplitudes of the time responses generated with varying aircraft speed and random external loads applied to the landing gear tire during a simplified landing operation. The results have shown both structural modifications’ effects regarding the shimmy damper’s shimmy amplitude reduction performance and the recommended ranges of shimmy damper parameters values that result in effective shimmy suppression. The results also suggest that the recommended ranges for shimmy damper parameters are better to be determined based on the resulting maximum amplitudes of the time responses simulated with dynamic inputs than the dynamic model’s eigen-value based steady-state stability.

Keywords: Dynamics Modeling
Dynamics Simulation
Landing Gear
Shimmy
Shimmy Damper
Vibration Stability
Advisor: Behdinan, Kamran
EXPLORING THE DEVELOPMENT OF TEACHER UNDERSTANDING AND USE OF INQUIRY-BASED INSTRUCTION IN CANADIAN AND WORLD STUDIES

Inquiry-based learning (IBL) has begun to be emphasized in the Canadian and World Studies (CWS) curriculum. Teacher understanding and usage of inquiry, however, is understudied and unclear. The present qualitative case study explores how teachers understand and use inquiry in CWS while taking part in two-part workshop on IBL administered through the board. Seven teachers were interviewed after each workshop and observations were conducted during the workshops. Using a developmental framework of professional development, findings show that teachers have a novice understanding of inquiry. Specifically, they have understood inquiry as a task or assignment rather than a process of learning. A prescriptive understanding of inquiry, exacerbated by systemic barriers for teachers and students, has led to pseudo-inquiry (practice that contains elements of inquiry but is not connected by the essence of inquiry).

Keywords: 21st century education
Canadian and World Studies
Inquiry-based learning
Secondary School
Teacher development
Advisor: Bascia, Nina
Design of a Passively Isolated Novel Thrust Stand (PINTS)

This thesis explores the viability of an inverted pendulum-type thrust stand for measuring forces from low thrust micropropulsion systems. The apparatus is designed around testing Space Flight Laboratory's 1 - 10 mN Cylindrical Hall Thruster, with passive mechanisms used for vibration isolation and thermal control. Ultimately, the mechanisms were not able to effectively isolate the stand from the vacuum chamber's vibrations, but filters used in postprocessing were able to attenuate their influence on the measurements. Testing with a thruster dummy showed that this prototype was able to repeatably measure static forces ranging from 2.796 - 11.12 mN to within 0.141 mN (1.67% FS), and is expected to achieve the same degree of accuracy for thrust measurements. The design is modular and can be easily adapted to forces ranging from 0.156 mN to 23.3 N, enabling highly accurate pre-flight thrust knowledge to be obtained across a wide variety of thrusters.

Keywords: Electric
Measurement
Noise
Pendulum
Propulsion
Thrust
Advisor: Zee, Robert E
Psychopathological and Neuropsychological Endophenotypes of Children with Disruptive Behaviour

Childhood Disruptive Behaviour Disorders (DBD) are a robust predictor of delinquency, academic failure, social difficulties, and persistent mental health disorders in adolescence and adulthood. Children with DBDs represent a highly heterogeneous group and the present study aimed to distill heterogeneity by identifying data-driven subgroups based on key dimensions of psychopathology and neuropsychological abilities. Data from children 6 – 12 years (n = 143), referred to a clinic for children with DBDs, were analyzed using Latent Class Analysis (LCA) to determine classes (i.e., subgroups) based on measures of children’s callous-unemotional (CU) traits, emotion regulation, and objective Executive Function (EF) task performance. Classes were compared on parent- and teacher-rated level of functional impairment, social functioning, and conduct problems. Classes with elevated levels of CU traits and poor selective attention had the highest conduct problems and impairment. This research may inform more refined assessment processes and future treatment innovation for children with DBDs.

Advisor: Andrade, Brendan F
Bedard, Anne-Claude V
Retrospective, Multicentre Matched Cohort Study Comparing Safety and Efficacy Outcomes of Intermittent Infusion and Continuous Infusion Vancomycin

Patients with good renal function receiving intermittent infusion vancomycin (IIV) may require total daily doses ≥4g to achieve trough concentrations of 15-20mg/L, increasing the risk of vancomycin associated nephrotoxicity (VAN). Continuous infusion vancomycin (CIV) may attain concentrations of 15-20mg/L with lower daily vancomycin doses, potentially reducing the risk of VAN. A retrospective chart review for eligible patients admitted to hospital between January 1, 2010 and December 31, 2016 was completed. Adult patients receiving >48 hours of vancomycin with ≥1 steady state vancomycin concentration were eligible. The primary outcome was to compare the rates of nephrotoxic risk and renal injury, defined by the RIFLE criteria, between CIV and IIV. Of 2136 patients identified, 146 CIV patients were identified and matched to 146 IIV patients. CIV was found to have a lower odds of developing nephrotoxic risk (odds ratio [OR] 0.42, 95% confidence interval [CI]0.21-0.98) and renal injury (OR 0.19, 95% CI 0.05-0.59, p=0.004).

Keywords: Infectious Diseases
Pharmacokinetics
Vancomycin
Advisor: Walker, Sandra AN
Micronutrients in Moringa oleifera and Their Potential in Food Fortification

Moringa oleifera is frequently endorsed for its high micronutrient content relative to other vegetables, but reported data on Moringa’s nutritional value is inconsistent. A comparative analysis on the macronutrient and micronutrient content of Moringa leaves and pods was conducted. Moringa oleifera contains multiple nutrients but its iron content is similar to that in spinach and its vitamin A content is lower than carrots on a dry basis. Nevertheless, Moringa’s abundance in micronutrient deficient regions makes it applicable as a natural fortificant. Bouillon cubes were identified as a suitable food vehicle for the incorporation of Moringa. Bench-scale cold extrusion processing was conducted to explore the feasibility of creating Moringa-fortified bouillon cubes. Nutritional characterization confirmed that supplemental fortificants would be required to enhance the nutritional value and stability of Moringa-fortified bouillon cubes. Flavours of Moringa may either be enhanced or suppressed depending on the application.

Keywords: food
food security
fortification
micronutrient
Moringa oleifera
sustainability
Advisor: Diosady, Levente L
Cheng, Yu-Ling
Amplitude-dependent Modulation of Bladder Function with Tibial Nerve Stimulation in a Continuous-fill Anesthetized Rat Model

Although percutaneous tibial nerve stimulation (PTNS) is considered a clinically-effective therapy for treating overactive bladder (OAB), its symptom suppression mechanism remains unclear. The goal of this study was to better understand the role of specific neural inputs on the bladder-inhibitory effects of tibial nerve stimulation (TNS). In 24 urethane-anesthetized rats, a suprapubic saline continuous-fill model was used to achieve repeated filling and emptying of the bladder. In each experiment, four TNS trials were applied in randomized order: no stimulation, Aβ fiber activation, Aδ fiber activation, and C fiber activation. Each trial was 30 minutes in duration, with a washout period of 60 to 90 minutes. Our findings showed that TNS evoked statistically significant post-stimulation changes in bladder function only at stimulation amplitudes that recruited unmyelinated C fibers. The bladder-inhibitory effects of TNS in a continuous-fill bladder model suggest that recruitment of small unmyelinated C fibers has important functional significance.

Keywords: c fiber
cystometry
overactive bladder
rats
tibial nerve stimulation
urodynamic
Advisor: Yoo, Paul B
Functional Connectivity in Children with Bilateral Cochlear Implants

By providing early bilateral cochlear implants, we can stimulate auditory development in congenitally deaf children. Electrophysiological studies have shown that despite early intervention, children with cochlear implants have some cortical differences which could reflect higher order deficits. In this thesis, we look at cortical auditory networks as a means to understand differences in auditory processing. To this end, a new implementation of a neural source localization method for electrophysiological data was created to allow more efficient data processing and facilitate further analyses. Finally, in a study of functional connectivity using a passive listening task we did not find overall stimulus or group-level network differences.

Keywords: Cochlear Implants
Deafness
EEG
Functional Connectivity
Advisor: Gordon, Karen A
Harrison, Robert V
Disparities in access to endometrial cancer surgery and the influence of morbid obesity on wait times

Background: We evaluated endometrial cancer surgery wait times in Ontario. Morbid obesity was the primary exposure. Methods: We evaluated women diagnosed with endometrioid endometrial adenocarcinoma from 2006-2015 who underwent hysterectomy. We compared wait times for women with and without morbid obesity using a Wilcoxon rank-sum test. We explored factors associated with the wait time using a generalized linear model under a generalized estimating equations approach, clustered at the level of the surgeon. Results: Median wait times were 62 days (IQR 43-88) for women with morbid obesity vs. 53 days (IQR 36-74) for those without (SMD=0.30). Factors associated with the wait time included morbid obesity, age, comorbidities, tumour grade, geographic distance, hospital procedure volume and availability of minimally invasive surgery. After multivariable adjustment, women with morbid obesity waited 12% longer. Interpretation: Women with morbid obesity experience longer wait times for endometrial cancer surgery than those without morbid obesity. Streamlined referral pathways may improve access.

Keywords: Endometrial cancer
Morbid obesity
Obesity
Quality of Care
Surgery
Wait times
Advisor: Baxter, Nancy N
Optical Imaging Strategies for High-Content Studies of Development

The advent of automated microscopy has brought forth the field of high-throughput microscopy. High throughput screens have become a commonly used approach to obtain streams of quantitative information from complex biological systems. High content microscopy is used in many fields of biology, such as drug discovery, genomic screens and recently developmental studies. Despite this, there remains many challenges that prohibit automated high throughput imaging of developmental processes. This thesis discusses some of the challenges of high throughput imaging of development, how they could be addressed and the merits of imaging platforms. The work presented here focuses on the design and application of custom optical solutions: an automated high-throughput imager, a high-content light sheet microscope, and an automated optical coherence tomography image processing pipeline, for studies of development.

Keywords: automation
development
high content
imaging
microscopy
Advisor: Yip, Christopher M
Development of Test Methods for Evaluating the Impact of Curing Methods on Chloride Penetration Resistance of the Concrete

Two potential test methods for evaluating the impact of different curing regimes on the durability of the cover layer over reinforcement in precast concrete elements were investigated. Current CSA and ASTM test methods are not adequate for this purpose. The first method is a modified ASTM C1585 test using salt water and comparing the rate of absorption and chloride ingress of formed surfaces to those of cut surfaces at 10 mm and 20 mm depths. The second is a modified NORDTEST NT 492 rapid chloride migration test, where slices are cut from a companion concrete slab and exposed to sodium chloride solution. Testing was conducted on two types of precast concretes meeting CSA exposure classes C-1 and C-XL. Both of these concretes were exposed to different curing regimes. The results indicate that accelerated curing provides similar durability to 7 days moist curing at ambient temperature.

Keywords: Chlorides
Concrete
Curing
Advisor: Hooton, Douglas R
The Effects of High-Intensity Interval Training on Piano Learning

High-intensity interval training (HIIT) improves implicit motor sequence learning (1,2). However, little is known about the impact of HIIT on the learning of explicit ecologically valid motor skills. We hypothesized that healthy volunteers who performed HIIT after explicit piano melody training would exhibit better retention of the learned melody, and better transfer to a new melody, than those who performed low-intensity exercise. Participants with no musical training underwent a graded maximal exercise test to determine their cardiorespiratory fitness. Later, participants practiced a piano melody before completing high- or low-intensity exercise. Participants were tested on the piano melody one hour, one day, and one week after initial practice. Performance was quantified by pitch and rhythm accuracy. Contrary to the hypothesis, HIIT did not enhance retention of the piano melody. However, HIIT did promote modest transfer to a new sequence. We conclude that HIIT may enhance explicit task-general motor sequence consolidation mechanisms.

Keywords: acute exercise
cardiovascular exercise
consolidation
kinesiology
motor learning
piano
Advisor: Chen, Joyce L
Standardization of Sonographic Prognostication of Prenatally Diagnosed Congenital Diaphragmatic Hernia (CDH) Across the North American Fetal Therapy Network (NAFTNet)

Congenital diaphragmatic hernia (CDH) is a potentially lethal condition, with antenatal prognostication relying heavily on sonographic lung area determination. Although critical for prenatal counselling, inter-observer variability has been demonstrated in lung area measurement. To understand this variability, current practice patterns were evaluated through surveys, interviews and human factors analysis with usability testing and inter-rater agreement was determined for the three published lung area measurement methods (i.e.: antero-posterior, longest and trace) across the North American Fetal Therapy Network (NAFTNet). When comparing lung area methods, the trace method demonstrated the highest inter-rater agreement. Human factors analysis identified variability in sonographic image selection criteria and lung area measurement technique. This data informed the development of a standardized protocol for antenatal sonographic assessment of CDH, which underwent iterative redesigns through consecutive Plan-Do-Study-Act cycles among physicians and sonographers to meet the needs of users with various expertise and ultimately standardize prenatal CDH prognostication across NAFTNet.

Keywords: Congenital diaphragmatic hernia
Fetal medicine
Fetal therapy
Prenatal ultrasound
Quality improvement
Sonographic prognostication
Advisor: Trbovich, Patricia
The Prion Protein is Embedded in a Molecular Environment that Modulates Transforming Growth Factor β and Integrin Signaling

The prion protein (PrP) is known for its fundamental role in a group of neurodegenerative disorders, aptly called prion diseases. The function of the normal cellular prion protein (PrPC) as well as the underlying molecular mechanisms that lead to neurotoxicity in disease are still unresolved. The previously discovered evolutionary relationship between PrP and ZIP zinc transporters implicated PrPC in morphogenetic reprogramming events but also uncovered surprising differences when comparing signaling pathways downstream of PrPC in separate cellular paradigms. To extend this line of research, we combined CRISPR-Cas9-based genetic engineering to generate four relevant murine PrP-deficient cell models, with quantitative mass spectrometry-based analyses to compare the molecular environment of PrP in these models. Interestingly, a unified theme emerged from these studies that placed PrPC in a specialized membrane domain that modulates TGF beta and integrin signaling.

Keywords: integrin
interactome
mass spectrometry
neurodegenerative disease
Prion protein
TGFB1
Advisor: Schmitt-Ulms, Gerold
How Does Competition Affect the Clinical Decision-Making of Dentists in Ontario?

Clinical decision-making is influenced by various factors, including patients’ disease risk and dentists’ age. We investigated these and other factors, including competition and their association with clinical decision-making. We gathered data through a cross-sectional survey of a random sample of general dentists in Ontario, Canada (n=3,201), which queried demographic, professional, and practice information. Competition was quantified as dentist geographic density via spatial analysis and through self-perceptions of competition. The outcome (treatment intensity or aggressiveness) was measured using clinical scenarios. One thousand and seventy-five dentists responded (33.6% response rate). Dentists who owned their practice, were

Keywords: Dental Public Health
Advisor: Quiñonez, Carlos
Development of a Novel Device for Non-invasive Leg Fluid Volume Measurements

Bioelectrical Impedance Analysis is a non-invasive technique to measure fluid content of tissues. Based on Ohm’s law, tissue impedance is measured by injecting current into tissue and measuring the voltage. Since impedance is inversely proportional to fluid volume, this is used to estimate the fluid volume of the segment. BIA devices can be expensive and require gel electrodes, which are inconvenient and can irritate the skin. Furthermore, the typical method of measuring whole-body impedance is inaccurate due to the non-uniform current path across the body. Since fluid volume in the leg is representative of whole-body hydration, we propose a novel device that uses dry electrodes in a convenient sock format to measure fluid volume in the leg. Based on previous research of our lab, an integrated system was developed. Finally, in collaboration with an industrial partner producing smart textiles, the feasibility of dry electrodes for use in BIA was assessed.

Keywords: Bioelectrical Impedance
Dry Electrodes
Fluid Volume
Textile Electrodes
Advisor: Yadollahi, Azadeh
Popovic, Milos R
Morphological Characterization of Para and Pro-Inflammatory Neutrophil Phenotypes Using Transmission Electron Microscopy

Neutrophils play a crucial role in the immune response, leaving the circulation to participate in an inflammatory response to perceived pathogens. Yet in the oral cavity, they are constantly recruited into the gingival sulcus even in health, producing no apparent clinical inflammation. It has been demonstrated that in this homeostatic state the neutrophils present a “partially active” phenotype, termed para-inflammation. To further investigate this phenotype, we studied the morphology of neutrophils obtained in vivo under transmission electron microscopy (TEM), in health and Chronic Periodontitis (CP), in the blood and the oral cavity. To study and compare the changes induced by the commensal oral bacteria in vitro, blood neutrophils were also incubated separately with S. oralis cultures. Our hypothesis was that the neutrophils in the healthy oral cavity will present a morphology consistent with para-inflammation, in contrast to the naïve phenotype of blood neutrophils, and the fully active, pro-inflammatory oral neutrophils in CP.

Keywords: Electron Microscopy
Inflammation
Neutrophils
Periodontitis
Advisor: Glogauer, Michael
Effect of Professional Training on Child Protection Workers' Conceptualization and Self-Efficacy in Domestic Violence Cases

Child exposure to domestic violence (DV) is a recognized form of child maltreatment. In Ontario, more cases are referred to child protection as a result of concerns of DV than for any other form of maltreatment. Child protection workers often do not understand the dynamics of DV and are not well equipped with the tools or knowledge to refer families to appropriate interventions. We examined the efficacy of professional training to improve worker responses to mothers who have experienced DV and fathers who have perpetrated DV. Findings revealed marked differences in workers' capacity and self-efficacy for conceptualizing the risks and needs of mothers and fathers. Professional training resulted in improvements to worker's conceptualization of mothers' risk and needs as they intersected with DV, not fathers'. Results will help lay the groundwork for future studies aimed at improving workers' knowledge and response to families in circumstances of DV.

Advisor: Scott, Katreena
Volunteering abroad: An uneven path towards critical praxis in international development

Despite decades of effort, international development has failed to meaningfully address the problems it seeks to solve. Drawing on existing literature and a Marxist-feminist theoretical framework, I argue that this failure stems from an ideological approach to social change that obscures the social relations at the root of poverty and inequality. This perspective points to a need to better understand how practitioners learn to engage with international development. Accordingly, I focus my research on volunteer abroad programs as a site of learning. Through interviews with ten former volunteers, I explore how their praxis changed through their placement experience. Although the existing literature on these programs does not offer much hope that these programs can foster critical learning, my findings show that some critical learning is possible. This learning is largely self-directed, resulting in uneven movement towards critical consciousness and a praxis that contains elements of both reproduction and transformative change.

Keywords: Adult Education
Development volunteering
International Development
Marxist-feminism
Volunteer Abroad
Advisor: Mojab, Shahrzad
Effect of Age and Immigration Status on the Oral Health and Dental Care Utilization of the Canadian population

The study was done to understand the oral health and dental-services utilization of older immigrants in Canada when compared to non-immigrant seniors and is a secondary analysis of data from the 2008/09 Canadian Community Health Survey: Healthy Aging component on respondents aged 45 and over. The outcome variables were self-reported oral health and dentist visits. Results indicate household income and education are significant predictors for both immigrant and non-immigrant seniors. Significant predictors for immigrant seniors include age, sex, marital status, household income, level of education and physician visits, while for non-immigrant seniors, household income and level of education were significant. Approaches for improving the oral health of immigrant seniors include: oral health education, dental screening, and awareness-raising. Approaches for improving dental utilization among immigrant seniors include: making dental care part of Canada’s universal health-care system, improving accessibility and changing legislation to improve the availability and access to dental insurance.

Keywords: Aging
Canada
Dental Public Health
Dental Utilization
Immigration
Oral Health Status
Advisor: Quinonez, Carlos