VictorJuiz/thesis huggingface dataset:
Monitoring Chemical Contamination of Medical Air Using Low-Cost Sensors
Keywords: Air pollution
Low-cost sensors
Medical Air

Medical air is used in hospitals for patients suffering from a wide range of health problems. This air is typically produced by pressurizing outdoor air on-site and supplying it to patients through piping system. Thus, it may contain chemical pollution from outdoor sources or can be polluted because of technical problems in the production system. Hospitals in North America are mandated to meet the medical air quality standards established by the United States Pharmacopeia (USP), yet medical air quality is often unmonitored. Thus, potentially failing to meet the patients' health requirements. In this study, concentration of CO, CO2, NOx, and O3, black carbon, and ultrafine particles in medical air were evaluated. Simultaneous measurements were made at the outdoor intake and patient-room ends of a medical air system at a Canadian hospital. The results showed a strong association between outdoor air pollution and the medical air quality based on correlation analysis.
The Intrinsically Photosensitive Retinal Ganglion Cell (ipRGC) Pathway and Its Role in Light-Induced Discomfort in Humans
Keywords: chromatic pupillometry
light-induced discomfort
melanopsin
photophobia
post-illumination pupil response
psychophysics

Photophobia is a complex phenomenon defined by light-driven painful sensations; commonly associated with pathology. Although underlying mechanisms remain poorly understood and no objective assessment exists, growing evidence suggests that the melanopsin-containing intrinsically photosensitive retinal ganglion cell (ipRGC) light irradiance pathway plays a critical role in transducing light into a painful percept. The purpose of this thesis is to investigate the properties of the recently discovered ipRGC pathway and its role in mediating light-induced discomfort. Using chromatic pupillometry, Study 1 demonstrates that melanopsin-mediated ipRGC signals are summated binocularly, a fundamental extension of the current understanding of this pathway. Using a novel objective tool to quantify light-induced visual discomfort, Study 2 then provides in-vivo evidence linking perceptual experience with features of the melanopsin system, which may mediate photophobia. In sum, this thesis expands our current understanding of the melanopsin pathway, and provides novel tools to assess photophobia in different clinical populations.
Veillametrics: An extramissive approach to analyze and visualize audio and visual sensory flux
Keywords: Extramission
Sensory attention
Sensory capacity
Sensory flux
Veillametry
Veillance

Veillametrics is the study of sensors and their sensing capacities. This thesis describes the methodologies employed to capture the ability-to-sense (veillance) of various arbitrary audio and visual sensors through space, in order to visualize, quantitatively generalize, and model sensory veillance. Using the veillametry framework, 3D models can be rendered to visualize the quantity of exposure to sensing projected onto various environmental surfaces.The work is extended to approximate the veillance model of a human eye using non-intrusive eye-tests, using eye gaze absement metrics. Such veillance models can extend traditional eye tracking methods to reveal greater details of the biosensor and its range and capacity to sense compared to simple gaze directions. The thesis relates the extramissive (emissive) nature of veillametry to compare to intromissive theories, and gives a framework to model phenomenons such as optical power decay, blurring, and amount of independent information captured by a sensor array.
Children’s Appraisals of Gender Variance: Understanding the Emergence of Negative Attitudes
Keywords: children's appraisals
gender
gender expression
gender norms
gender variance
peer relations

Among children ages 4-to-5- and 8-to-9-years-old (N = 142; 47.2% boys), multiple measures of social preference were employed to gauge appraisals of target boys and girls depicted as gender-typical or gender-variant. Children’s gender-typed behaviour and implicit attitudes as well as parental endorsement of gender stereotypes were also assessed. Social preferences did not precisely align across measures—although some consistent patterns were observed. Among boys, gender-typed preferences increased with age; older boys preferred the gender-typical boy and rated gender-typical peers more favourably. Girls showed a same-sex preference; but older girls also showed interest in being friends with the gender-variant boy. Older children rated the gender-variant boy as less preferred by others; and all children rated gender-variant children as less happy. Boys and girls expressed preferences for boy-typed and girl-typed activities, respectively. Parental endorsement of femininity was particularly associated with more positive appraisals of feminine peers. Implications for future research are discussed.
The Effects of Alzheimer's Disease on Synaptic Plasticity and the cAMP/PKA Pathway
Keywords: Alzheimer's Disease
electrophysiology
LTP
Synaptic Plasticity

Alzheimer’s Disease (AD) is a physiologically devastating form of dementia, yet an understanding of AD pathology remains elusive. One promising avenue of research is to examine synaptic plasticity within the brain centres of learning and memory in animal models of AD. Long-term potentiation (LTP) is a model of learning and memory at the synaptic level, and deficits in LTP have been proposed in AD. The aim of this work is to examine whether synaptic defects in AD involve a neuronal signalling cascade: the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) pathway. This research uses novel modes of LTP induction which manipulate the course of LTP induction. Examinations reveal alterations in basal synaptic transmission in AD mouse models. The use of a cAMP/PKA enhancing drug revealed a potential dysregulation in the cAMP/PKA cascade. Lastly, coastline analysis showed potentiation induced hyperexcitability at synapses of an AD mouse model.
Towards Long-Term Vision-Based Localization in Support of Monocular Visual Teach and Repeat
Keywords: Learning Descriptors
Long-Term Localization
SLAM
Visual Descriptor
Visual Teach and Repeat

This thesis presents an unsupervised learning framework within the Visual Teach and Repeat system to enable improved localization performance in the presence of lighting and scene changes. The resulting place-and-time-dependent binary descriptor is able to be updated as new experiences are gathered. We hypothesize that adapting the description function to a specific environment will improve the localization performance and allow the system to operate for a longer period of time before localization failure. We also present a low-cost monocular Visual Teach and Repeat system, which uses a calibrated camera and wheel odometry measurements for navigation in both indoor and outdoor environments. These two parts are then combined with the end goal of achieving a low-cost, robust, and easily deployable system that enables navigation in complex indoor and outdoor environments with the eventual goal of long-term operation.
Basal Forebrain Transient Cholinergic Signal in Prefrontal Cortex and its Role in Associative Learning
Keywords: basal forebrain
medial prefrontal cortex
memory

Basal forebrain (BF) cholinergic neurons constitute a main neuromodulatory system in the brain and densely innervate to neocortex and hippocampus. Traditionally, acetylcholine (ACh) released from BF cholinergic neurons are thought to slowly influence neuronal network to regulate arousal, attention, and learning and memory. However, accumulating studies report phasic ACh release upon events with innate or learned salience. Thus, the present study investigated its role in acquisition of trace eyeblink conditioning where a preceding tone is paired with an eyelid shock. Here, it was shown that suppressing cholinergic activity in medial prefrontal cortex (mPFC) during eyelid shock facilitated the formation of the tone-shock association. The enhanced learning was accompanied by elevated mPFC network activities indicated by neuronal activity marker, c-Fos. These findings suggest that phasic ACh release does not serve as a reinforcement signal in mPFC. Rather, it may regulate cortical network state by differentially activating local excitatory and inhibitory neurons.
Learn English, go to school, get a job… and play sport? Immigrant Youth Recreation and the Settlement Service Agency
Keywords: Agency
Assimilation
Recreation
Settlement Services
Sport for Development

This community-based study explored the experiences of immigrant youth in Toronto who participate in recreational programming at a settlement service agency, CoalitionTO*. To guide my findings, I applied a variety of transdisciplinary theoretical frameworks, such as cultural capital, social inclusion, critical race theory, and modern assimilation theories. I utilized participant observation and interviews with youth participants and staff members. My results found that despite strong multiculturalism narratives, assimilation into dominant institutions was viewed as expectation of migration and White, Canadian physical culture was perceived by all stakeholders as an effective means of facilitating the settlement of youth. However, youth were not passive within this process; they exerted agency to reflect on their positionality and made decisions to enhance their social mobility. This study unpacks the complex tensions between assimilation and social inclusion and calls for a greater examination of the broader socio-political context surrounding sport/recreation.
The ear: Gateway to the brain. Exploring the Feasibility of a novel in-ear electroencephalography device in an auditory brain-computer interface
Keywords: auditory evoked response
auditory steady state response
brain-computer interface
electroencephalography
in-ear EEG

A brain-computer interface (BCI) enables communication using signals directly from the brain. Electroencephalography (EEG) is often used to collect these signals and commonly involves scalp-based electrodes which are conspicuous, and uncomfortable over long periods. In-ear EEG devices address many of these shortcomings and can discreetly measure brain activity from within the ear canal. We designed an in-ear EEG device usable with a commercial EEG amplifier and tested this device in an auditory BCI involving auditory evoked potentials (AEPs) and the auditory steady state response (ASSR). Using scalp electrodes, AEP accuracy was ~ 79 %, and focus-modulated ASSR accuracies were above chance in 3 of 7 participants. Equivalent neural responses were evidenced in the in-ear recordings. However, classification outcomes were poor, reflecting challenges with in-ear measurement and the reduced number of electrodes. This study highlights the need for further research into device morphologies and paradigms for in-ear EEG.
A Modular Heterogeneous Communication Layer for a Cluster of FPGAs and CPUs
Keywords: Communication Layer
Data Centers
FPGAs
Heterogeneous Computing
High-Performance Computing
Reconfigurable Computing

A key infrastructure required to make heterogeneous clusters easier to use is a standard communication mechanism between computing nodes. Without this infrastructure, application developers of multi-FPGA applications are forced to develop their own custom communication cores for hardware kernels that can communicate. This problem is significantly worse at a data center scale. This thesis shows how introducing modularity into an existing orchestration platform makes it possible to automatically and interchangeably support different underlying network protocols and multiple communication models for a multi-FPGA platform. We show that it is straightforward to connect the communication models implemented in the FPGAs to compatible software implementations of the same models so that it is easy to build heterogeneous applications using CPUs and FPGAs. Our results have shown that the heterogeneous communication has introduced very little area overhead in the FPGAs and can still perform at line-rate, bottlenecked solely by the network protocols.
Designing microporous layers for polymer electrolyte membrane fuel cells: pore network modelling and fabrication
Keywords: energy
Fuel cell
polymer electrolyte membrane
pore network modelling
renewable energy

Liquid water transport and oxygen diffusion within the gas diffusion layer (GDL) play key roles in the performance of a polymer electrolyte membrane (PEM) fuel cell. Understanding how liquid water and oxygen are transported through the GDL is crucial for informing future fuel cell material designs. This thesis contains two studies, one numerical and one experimental, that are focused on liquid water and gas transport in GDLs. The first study is an investigation of how liquid and gas transport in the GDL are affected by increasing microporous layer (MPL) intrusion into the carbon fiber substrate. The second study is an examination of the transport mechanisms in the MPL via the fabrication and testing of GDLs that were entirely composed of MPL (called standalone MPLs). Together, these two studies provide a deeper understanding of how novel applications of the MPL can unlock higher performance in PEM fuel cells.
Program Sherlock: A Tool for Stochastic Finite Element Analysis and Field Assessment of Concrete Structures
Keywords: Monte Carlo Simulations
Nonlinear Finite Element Analysis
Reinforced Concrete
Stochastic Analysis
Structural Assessment
Structural Health Monitoring

The use of stochastic analysis as a way to better simulate the uncertainty effects often encountered in structural evaluation was investigated. Unlike deterministic analysis where the sensitivity to material inputs cannot be captured, stochastic simulations with the addition of established material distributions and damage prediction models can provide a higher level of confidence in structural behaviour. Stochastic analysis capability was implemented into VecTor2, a nonlinear finite element analysis program for reinforced concrete structures, and simulations were performed on a series of reinforced concrete beams and shear walls. The simulation results were compared against the deterministic and experimental results and found to be an adequate substitute whilst providing a level of confidence consistent with each specimen. In an attempt to narrow the confidence interval, the methodology of incorporating early stage field measurements with stochastic results was explored. Using early stage parameters such as deflections, crack widths, and reinforcement strains, the stochastic output was recalibrated to produce more accurate results. The implementation of such an analysis as a field assessment tool was examined.
Spatial and Temporal Analysis of Hydraulic Conductivity, Snow Depth and Soil Properties of a Bioretention System
Keywords: Bioretention
Heterogeneity
Hydraulic Conductivity
Soil Properties
Spatial
Temporal

Bioretention Cells (BC) are a Low Impact Development technology that provide distributed storm water management near to its source. Most research envisages BC as a black box with ambiguous processes between the input and the output. This thesis aims to consider BCs as heterogeneous systems with physical processes that vary both spatially and temporally. For this study, a 5-year-old BC at Kortright Centre for Conservation in Vaughan, Ontario is used as an investigation area. The following results were observed. D30 and D60 were lower in the central flow path due to sedimentation and suspended solids deposition. Organic content was negatively correlated with bulk density. Ksat in the central pathway region and non-central pathway region showed a mild rise during and a mild decrease respectively during warm winter days possibly due to freeze-thaw action. However, after statistical outliers were identified and removed from the Ksat data, this effect was not observed.
Value Recovery from Metallurgical Slags Through Air Atomization
Keywords: Air atomization
Heat recovery
Heat transfer
Metallurgy
Slag granulation
Slag processing

Value recovery from waste products in metal processing operations is a growing field in metallurgy. A computer model was developed to assess the feasibility of simultaneous granulation and heat recovery from molten slag, and an experimental study was carried out to analyse the properties of solidified slag samples. The model facilitates isolation of selected variables to determine their effect on atomization. Model results determined that smaller granules and lower air:slag ratios increase the process heat recovery efficiency, while the initial air temperature was shown to have a minimal effect on atomization. Empirical analysis of sintering temperature identified maximum post-atomization temperatures for granules. Upon comparison with model results, it is concluded that simultaneous granulation and heat recovery is possible as the outer shell is sufficiently cooled, and the core cooling rate exceeds the expected critical cooling rate. Hardness and abrasion resistance were studied to determine optimal cooling conditions for property maximization.
Manifestations Of Inequity In Egypt’s Two-Tiered Healthcare System
Keywords: Egypt
Inequity
Privatization
Social services

In planning healthcare systems, challenges and debates may vary significantly from one country to the next. Direct privatization, public-private partnerships, cost recovery programs, and user fees have often been promoted as remedies to ailing healthcare systems. In fact, market-driven healthcare reforms and development strategies continue to drive the privatization of healthcare services in many countries. But, it is often the case, particularly in low- and middle-income countries in the Global South, that when these measures are implemented large disparities emerge and are maintained between the public and private tiers. Focusing on the case of Egypt, my thesis addresses the following question: What are the manifestations of inequity between private for-profit and public hospitals in Egypt, with regards to quality and access to emergency care? More specifically, this thesis seeks to examine the perceptions of physicians with regards to disparities in access and quality of emergency care.
Fluorine-Free Omniphobic Flexible Packaging Papers Containing Low Consistency Refined Mechanical and Chemical Pulp Blend
Keywords: Coating
Co-Refining
Hydrophobic
Oleophobic
Pulp and Paper
Sack Paper

In this study, the effect of partial substitution of chemical pulp by relatively lower-cost mechanical fibres for the production of flexible packaging paper was examined. In particular, the objective of this work was to obtain the optimum substitution percentage and refining conditions capable of providing adequate performance and reduced production cost for sack papers. Results indicated that the pulp mixtures containing 10% mechanical pulp and co-refined at low intensity (0.5 J/m) had a similar performance compared to the control samples made of 100% refined chemical pulp. To impart omniphobic properties to the packaging samples, novel fluorine-free coating formulations containing polyvinyl alcohol (PVA) and polymethylhydrosiloxane (PMHS) emulsions were developed. Contact angle measurement and scanning electron microscopy (SEM) showed that the treated sampled exhibited acceptable wetting behavior and barrier properties. This novel coating formulation is an eco-friendly alternative to fluorinated-based materials currently used in the food packaging industry.
Removal of 3-chloro-4-dichloromethyl-5-hydroxy-2(5H)-furanone (MX) Precursors during Water Treatment Biofiltration
Keywords: 3-chloro-4-dichloromethyl-5-hydroxy-2(5H)-furanone
biofiltration
Mutagen-X
MX
water treatment

MX precursor removal was compared at pilot-scale in continuously and cyclically operated biofilters with empty bed contact times (EBCTs) of 15 and 30 minutes. Water and filter media samples were collected under both ambient water quality conditions, as well as during a spike of 7 mg/L humic acid. MX formation potential (FP) removals ranged from 26 to 49% and 45 to 61% under ambient precursor and spiked conditions, respectively, suggesting that biofiltration was capable of removing or altering MX precursors. Removal was very strongly correlated (R=0.90) with ATP (a measure of biomass density) for all trials. MX FP reduction was significantly higher (p
The Contribution of Biofilm to Nitrogenous Disinfection ByProduct Formation in Full-Scale Cyclically-Operated Drinking Water Biofilters
Keywords: Biofiltration
Disinfection By-Products
Extracellular Polymeric Substances
N-Nitrosodimethylamine

Biofiltration can be effective for disinfection by-product (DBP) precursor control, however few studies have considered its role in the potential formation of DBPs. The objective of this study was to determine the contribution of biofilm-related materials to form nitrogen-containing DBPs upon chloramination and to determine the influence of cyclical biofilter operation on DBP precursor removal. Biologically active media was sampled from a full-scale biofilter operating under cold-water conditions (3.6 ± 0.5°C) and its components were extracted with a cation exchange resin into a phosphate buffering solution. N-nitrosodimethylamine (NDMA) and haloacetonitrile (HAN4) formation potential tests conducted on extracted biofilm yielded 0.80 ± 0.27 ng NDMA/g media and 18.7 ± 3.3 ng dichloroacetonitrile (DCAN)/g media. However, an analysis of NDMA formation potential and biological surrogates in the effluent of a full-scale cyclically-operated biofilter did not show release of NDMA precursors during filter start-up after stagnation periods of 6 hours or more.
Characterizing the left and right atrial adaptations in middle-aged chronic endurance athletes: a cMRI study.
Keywords: Athlete's Heart
Cardiac Magnetic Resonance Imaging
Health Science
Kinesiology

Chronic endurance exercise induces several hemodynamic stressors on the cardiovascular system resulting in adaptations collectively defined as the Athlete’s Heart. We characterized the morphological adaptations in the left atrium (LA) and right atrium (RA) in response to chronic endurance training using the gold-standard imaging modality of cardiac magnetic resonance imaging (cMRI) in both middle-aged elite endurance athletes (n=71) and recreationally active controls (n=19). All subjects underwent maximal exercise testing (VO2max), exercise history questionnaires, and received a cMRI scan. Endurance athletes demonstrated objectively larger LA and RA volumes than controls. LA and RA volumes were positively correlated to VO2max, although not lifetime endurance hours. Male athletes demonstrated greater atrial dimensions than female athletes. Overall there was a weak ability to predict the magnitude of atrial remodeling specific to an athlete, suggesting a large heterogeneity in the atrial response to chronic endurance activity in the middle-aged athletic cohort.
A Formal Analysis of the Propagation for the Ellipsoid Global Constraint and an Application to the Selective Tree Breeding Problem
Keywords: Constraint Programming
Constraints
Nonlinear Optimization
Propagation Algorithms

The ELLIPSOID global constraint is one of the few global constraints used for reasoning about convex quadratic functions. This thesis compares the strengths of the most successful propagation algorithm for the ELLIPSOID global constraint, namely the BOX propagation, against the standard propagation algorithm based on the expression tree of the mathematical formulation as implemented, for example, in the well-known solver IBM ILOG CP Optimizer. We perform a formal analysis of the strengths of both propagation algorithms, showing that there are conditions under which the BOX propagation algorithm is not as good as the standard propagation algorithm. We apply the ELLIPSOID global constraint to the selective tree breeding problem, a known problem from the forest genetics literature. Our computational study shows that the ELLIPSOID global constraint is not a suitable candidate for this particular problem, which is consistent with the findings from our theoretical analysis.