VictorJuiz/thesis huggingface dataset:
Impact of Backwash on Biofiltration-related Nitrogenous Disinfection By-product Formation
Keywords: Backwash
Biofilm
Biofiltration
Disinfection By-Products
Filter ripening
N-Nitrosodimethylamine

Previous studies have reported that biofilm extracted from full-scale biofilters can serve as nitrogenous disinfection by-product (N-DBP) precursors. Detached biofilm could escape during filter ripening and form N-DBP upon chloramination. This study examined the potential breakthrough of biofilm and N-DBP precursors during filter ripening at two water treatment plants (WTPs). The presence of biofilm was estimated by total adenosine triphosphate levels (tATP); N-DBP formation potential (FP) tests were conducted to quantify N-nitrosodimethylamine (NDMA) and haloacetonitrile precursors. While tATP peaks in filter effluent were observed post backwash at both WTPs, temporary increases of effluent NDMA FP were only observed during filter ripening where particle-associated NDMA precursors served as the dominant contributor. Overall, biofilters examined in this study demonstrated a consistent removal of NDMA FP regardless of the filter ripening process.
Current Math Teacher Perceptions of STEM Careers
Keywords: Engineering Education
STEM

This study explores teachers’ perceptions of Science, Technology, Engineering, and Mathematics (STEM) Education and what role it plays in today’s mathematics classroom. The following three research questions are explored. How do currently practicing teachers perceive their understanding of STEM education and STEM careers in the math classroom? How do currently practicing teachers perceive their students’ degree of intrinsic motivation in mathematics? How do currently practicing teachers perceive the use of gamification as a means to affect students’ level of intrinsic motivation in the math classroom? Key findings include the following: teachers valued STEM career discussion in the classroom as it offers a channel through which knowledge can be transferred, teachers build rapport with students when they draw upon their own experience with STEM careers. Better understanding of gamification at the classroom level is recommended before it can be a useful medium for motivating students in math.
Towards the Development of a Sensor for Measuring Soil Stresses in the Cyclic Simple Shear Apparatus
Keywords: Sensor
Soil Liquefaction
Soil Stress

In locations with seismic activity, structures are susceptible to damage or failure due to soil liquefaction. Determining the horizontal stresses in soil before and during cyclic loading, which is a fundamental challenge in geotechnical engineering, is important for interpreting liquefaction susceptibility and predicting foundation response to earthquake loading. The applicability of various existing sensing devices and concepts for measuring stresses in soil were investigated. Six passive and two active sensor systems were designed and evaluated when buried within a soil specimen. The evaluations showed that none of the sensors functioned well in soil, even for those that minimized diaphragm deflection to mitigate soil arching effects. Major limiting factors observed in the results included hysteresis, non-linearity, lack of repeatability, and effects of placing sensors in soil. The disturbance induced by sensor placement in soil appears to be a dominating factor acting against reliable measurement of horizontal stresses, even under laboratory conditions.
Testing Trade-offs in Dispersal and Competition in a Guild of Semi-aquatic Backswimmers
Keywords: backswimmers
coexistence
competition
competition-colonization trade-off
dispersal
ecology

Theory has proposed that a trade-off causing negative covariance in competitive and colonization abilities (the competition-colonization trade-off) is an important mechanism enabling coexistence of species across local and regional scales. However, empirical tests of this trade-off are limited, especially in naturalistic conditions with active dispersers; organisms capable of making their own movement decisions. I tested the competition-colonization trade-off in two co-occurring flight-capable semi-aquatic insect backswimmers (Notonecta undulata and Notonecta irrorata). Using field mesocosm experiments and laboratory experiments, I measured components of dispersal and competition to determine if and how the competition-colonization trade-off enables coexistence in this system. This thesis reveals that backswimmer species exhibited clear differences in dispersal behaviour and yet competition proved to be multi-faceted and context-dependent. This work suggests that in active dispersers, there is a great deal of complexity in competition and dispersal. Future studies of the competition-colonization trade-off in naturalistic communities should incorporate these complexities.
A Direct Role for Interferon-alpha in the Disruption of B Cell Tolerance in Systemic Lupus Erythematosus
Keywords: Autoimmunity
B Cells
Interferon-Alpha
Lupus
SLE

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the production of pathogenic anti-nuclear antibodies (ANA). A central mediator of SLE is Interferon-Alpha (IFNα), which is elevated in the blood of SLE patients. IFNα is thought to contribute to ANA production indirectly through the activation of T cells and dendritic cells; however, IFNα has been shown to have a number of direct stimulatory effects on B cells in vitro. This thesis examined the direct impact of elevated IFNα levels on B cell tolerance mechanisms in vivo. It was found that the elevation of IFNα alone in murine models of B cell tolerance was associated with significant increases in autoantibody production and impairment of many B cell tolerance mechanisms. These results suggest that elevated IFNα levels in SLE patients may directly drive the production of pathogenic ANA, and highlight IFNα as a potential therapeutic target in this disease.
Ultrasound-targeted microRNA-26a Therapy for Abdominal Aortic Aneurysms
Keywords: Aneurysm
Aorta
miRNA

Abdominal aortic aneurysms (AAA) affect ~5% of adults and are characterized by vessel inflammation, aortic smooth muscle cell (haSMC) depletion and extracellular matrix (ECM) degradation. microRNA-26a (miR-26a) regulates haSMC function but is reduced in human AAA. We induced targeted delivery of miR-26a or scrambled-control miR to the infrarenal aorta of a clinically relevant rat AAA model using ultrasound-targeted microbubble destruction (UTMD). An additional control group received no therapy. In-vitro, haSMCs were stimulated with the inflammatory interleukin-1β (IL-1β; 20ng/ml) and transfected with miR-26a, antimiR-26a and scrambled-control miR. In-vivo, UTMD of miR-26a downregulated inflammatory cytokines (IL-1β, IL-6 and TGF-β) and elastolytic enzymes (MMP-2 and MMP-9), leading to reduced ECM degradation and AAA dilation. In-vitro, miR-26a downregulated TGF-β signaling (SMAD1 and SMAD4) and differentiation markers (ACTA2 and TAGLN) but enhanced haSMC proliferation, which alludes to a phenotypic switch towards greater haSMC survival. Thus, this study demonstrates a promising miRNA-based UTMD therapy for AAA.
Relative Orbit Acquisition and Maintenance of Satellite Formations Using Ground-Based Guidance and Control
Keywords: Constellation
Control
Distributed Space Systems
GNC
Guidance
Satellite Formation Flying

Small satellite formation flying missions are positioned to deliver rapid advancement in the application of space-based infrastructure. These missions rely on robust guidance and control systems to effectively manage the spatial distribution of spacecraft within a formation. To this end, development of a ground-based guidance and control system is presented in this thesis; this system uses impulsive maneuvers to reconfigure and maintain orbital satellite formations with arbitrary relative geometries and numbers of spacecraft. A delta-v optimal guidance and control system in an operational software architecture is described, and the stages of development are validated through simulated scenarios and flight-representative hardware-in-the-loop testing. The system performance is then verified with analysis of on-orbit results from initialization and station-keeping operations of the HawkEye 360 Pathfinder formation. Successful formation flying operations for the HawkEye 360 Pathfinder mission are ongoing and continue to be scheduled around payload operations with minimal operator input required.
Negotiating Citizenship: Mediatized Migration and the Canadian Data Border
Keywords: anticipatory governace
citizenship
humanitarian securitization
irregular migration
media institutions

This thesis reflects upon the anomalous rise of irregular migration into Canada near the town of Lacolle, Quebec and the response of the Canadian government in the context of prevalent networked communications. Conceiving of politics as performance, the research engages in a systematic content analysis of Canadian Press and Agence France Press coverage of arrivals through Lacolle to identify an official ‘institutional narrative’. Subsequently, I test this institutional narrative, which privileges the voices of Canadian political elites, establishing my own ‘narrative of encounter’ through analysis of a variety of legislation, policy, and internal documents obtained both publicly and through Canada’s Access to Information System. This produced novel insights regarding how the massive proliferation of networked communication has shaped possibilities for citizenship and authority at the Canadian border in many paradoxical and ironic ways.
Revisiting the Interaction Between Memory and Perception in Emotionally Enhanced Vividness
Keywords: Memory
Perception
Vividness

Emotionally salient visual stimuli are perceived with more clarity than neutral ones (Markovic et al. 2014). It has been hypothesized that the advantage of enhancement at perception is passed on to memory (Markovic et al., 2014, Todd et al. 2012). This study investigates the influence of memory and perception on emotionally enhanced vividness through the employment of the El Greco strategy. The first experiment revealed the opposite effect to the previous literature, suggesting emotional images are either remembered worse, or perceived more clearly at response than they are remembered. To elucidate which of these two hypotheses better explains these results, a second experiment was conducted. As expected from the latter hypothesis, and consistent with the previous literature, significantly reduced vividness reporting occurred for neutral images when reported on emotional response images. These findings suggest that emotional enhancements of vividness occur at perception are not fully passed to short-term memory.
A Representative Experience Sampling Study of Everyday Empathy
Keywords: Compassion
Empathy
Experience Sampling
Perspective Taking
Prosocial
Subjective Well-being

Empathy — the ability to understand, share, and care about the emotions of others — has received considerable attention. However, important questions about empathy remain unsettled; including its frequency, whether it’s a choice, and its impacts on prosociality and well-being. The current study advances understanding by investigating empathy outside the lab. Participants were recruited with quota sampling for age, education, income, region, gender, and ethnicity. They completed a baseline survey, then a week of experience sampling where they were prompted 7 times daily and asked whether they experienced or received empathy in the last 15 minutes. This research tests links between trait and state empathy, and clarifies the relationships between empathy and prosocial behavior, and empathy and well-being. One emerging theme was the importance of positive empathy. This study provides a novel description of empathy in everyday life, and an indication of the utility of experience sampling for understanding empathy in context.
Interpersonal Problems and the Social Reality of Psychological Need Fulfillment
Keywords: hierarchy
interpersonal perception
interpersonal problems
need fulfillment

People with interpersonal problems have difficulty adapting to situational demands and navigating social hierarchies, which has important implications for the satisfaction of their basic psychological needs for autonomy, competence, and relatedness. Though people with interpersonal problems are likely to experience frustrated need fulfillment, the mechanisms explaining this relationship are not well understood. One such mechanism is interpersonal perception specifically the way a person is perceived by their peers (target effects) and the way they perceive others (perceiver effects). This study investigated whether target and/or perceiver effects mediated the relationship between interpersonal problems and psychological need fulfillment. Undergraduate students participated in a group interaction task. Measures of personality, interpersonal problems, and psychological need fulfillment were completed pre-task and need fulfillment was measured again post-task. Results demonstrated that people with dominance-related problems reported lower autonomy and relatedness need satisfaction post-task in part because they tended to perceive their peers as competitive.
Chronic Stress Induces Specific Cellular and Morphological Astroglial Changes Associated with Depressive-like Phenotypes
Keywords: Astrocytes
Chronic Stress
Major Depression
Rodent Models
Tripartite Synapse

In major depressive disorder (MDD), one of the most consistent findings from post-mortem studies is decreased astroglia number and function in limbic brain regions including the prefrontal cortex (PFC). However, the contribution of astroglial pathology in synaptic dysfunction and depressive symptoms associated with MDD remains unclear. Here, using chronic restraint stress (CRS) in mice to model MDD, we demonstrate that CRS induced time-dependant decreases in astrocytic and synaptic protein expression in the PFC, which correlated with both anxiety- and anhedonia-like deficits. We also investigated CRS effects on astroglial cell morphology using Sholl analysis and found CRS decreased distal processes while increasing proximal processes. This structural rearrangement may parallel functional astrocytic and synaptic changes. Furthermore, we validated a custom-designed plasmid, allowing astroglial activity enhancement in vitro. This novel tool will allow us to test if PFC astroglial activation prevents CRS effects. This work substantiates astroglia as targets for antidepressant development.
Effects of Forest Management and Experimental Dead Wood Removal on Macrofungal Communities in Boreal, Mixedwood Forests of Ontario
Keywords: boreal forest
coarse woody debris
forest management
macrofungi
old-growth forest

Boreal macrofungi are an ecologically diverse group of organisms that are threatened by forest management, including harvest-associated reductions in coarse woody debris (CWD) supplies. In this thesis, I compared richness and composition of macrofungal communities in old-growth and post-logged mixedwood stands in boreal northeastern Ontario, including post-logged stands in which downed CWD availability had been experimentally manipulated. Canonical Correspondence Analysis showed a strong distinction between macrofungal communities of unlogged and logged plots, correlated with harvest-related reductions in large-diameter CWD supplies. Rarefaction revealed that macrofungal richness, particularly of saprotrophs, was higher in unlogged compared to logged plots, especially those with experimentally-reduced CWD supplies. These results demonstrate the negative effects of post-harvest decreases in CWD on macrofungal richness and suggest that forest management in Canada may, over time, lead to the harvest-related biodiversity losses of boreal Europe. Management practices that better emulate habitat conditions in old-growth stands, including availability of large-diameter CWD, are discussed.
Towards the Implementation of an Activity-based Travel Demand Model for Emerging Cities: Integrating TASHA and MATSim
Keywords: activity-based
Africa
decision making
developing countries
emerging cities
travel behaviour

In many emerging cities, there are various proposals for transit-oriented infrastructural investments and transport policies. However, the effort to understand possible current and future effects of alternative investment strategies, socio-economic trends, and travel behaviour patterns before deciding on pressing projects is lacking. Finding a solution to this problem would enable rapid identification and representation of local transport need with all possible policy effects of public transport strategy evaluation. By identifying modelling challenges in an application context on data and modelling framework to use, and demonstrating methods taken to overcome these challenges, this study proposes practical steps decision-makers can apply to better forecast future travel patterns, by exploring an “integrate-refine-and-transfer” strategy of the operational Greater Toronto Area travel demand model (GTAModel) implementation to an emerging city. The modelling approach used involves the integration of the household-based activity scheduling model travel activity scheduler for household agents (TASHA) with Multi-Agent Transport Simulation (MATSim).
Depression, Anxiety, and Quality of Life in Postconcussion Syndrome
Keywords: Anxiety
Concussion
Depression
Postconcussion Syndrome
Quality of Life

Postconcussion syndrome (PCS) affects a considerable percentage of concussion patients. A follow-up analysis was conducted to evaluate the occurrence of anxiety and depression in patients with PCS and measure their quality of life. A questionnaire package consisting of the Depression and Anxiety Stress Scale (DASS), the WHO Quality of Life Assessment (WHOQOL-Bref), and a general follow-up questionnaire was sent to 526 PCS patients. A total of 37 (35.2%) patients had symptoms of anxiety, depression, or both. 8 (7.6%) patients had symptoms of depression alone, 8 (7.6%) patients had symptoms of anxiety alone, and 21 patient (20%) had symptoms of both. The number of previous concussions was significantly correlated with increased DASS anxiety (r=0.207, p=0.0034) and depression (r=0.264, p=0.006) scores. Increased DASS scores were significantly correlated with a poorer quality of life in all four domains of the WHOQOL-Bref. Thus, concussion-related symptoms of depression and anxiety are important public health concerns.
Women Ice Hockey Officials and Gender Relations in Officiating
Keywords: Equality
Gender
Hockey
Officials
Women

This study explores the current experiences of women ice hockey officials in Canada. To guide my research, I applied a Critical Feminist Theory framework to data from document analyses, observations of hockey games and semi-structured interviews with women ice hockey officials from across Canada. The results show that women ice hockey officials face numerous challenges in obtaining higher certification levels and having opportunities to officiate higher level hockey games. The career paths and career contingencies for women ice hockey officials differ from their men colleagues due to the hegemonic structures that construct hockey as a masculine space, and as a result, these structures directly influenced the participating women’s ability to advance in officiating in Canada. The participants shared experiences of exclusion at sites of training and education, limitations to advancing, and disinvolvement such as quitting/dropping-out, and retirement. This study unpacks the complex tensions between the ‘love of the game’ and systemic hegemonic exclusion institutionally, and calls for policy and procedures to better support women ice hockey officials.
Motif Elucidation in ChIP-seq Datasets with a Knockout Control
Keywords: ChIP-seq
DNA motif
knockout control
transcription factor

Chromatin immunoprecipitation-sequencing (ChIP-seq) is widely used to find transcription factor binding sites, but suffers from various sources of noise. Knocking out the target factor mitigates noise by acting as a negative control. Paired wild-type and knockout experiments can generate improved motifs but require optimal differential analysis. We introduce peaKO—a method to automatically optimize motif analyses with knockout controls, which we compare to two other methods. PeaKO often improves elucidation of the target factor and highlights the benefits of knockout controls. It is freely available at https://peako.hoffmanlab.org.
Identifying the Rhodoquinone (RQ) Biosynthetic Pathway in Search of Novel Antihelminthic Targets
Keywords: anaerobic
caenohabditis elegans
C. elegans
helminth
metabolism
rhodoquinone

Helminths infect a quarter of the world’s population. Infections caused by these parasitic nematodes, cestodes and trematodes can lead to complications such as severe malnutrition, pneumonia and liver failure. Following the ingestion of the helminth the parasites are exposed to a hypoxic environment inside the host’s digestive tract. To survive, helminths rely on an anaerobic metabolism called fumarate respiration. Fumarate respiration requires a molecule called rhodoquinone (RQ). Although RQ was discovered over 50 years ago its biosynthetic pathway is unknown. Discovering how RQ is synthesized could lead to potential targets for new antihelminthic treatments. Resistance to all classes of antihelminthic drugs has been reported and it is critical that new treatments are found. By analyzing quinone extracts from the non-parasitic nematode C. elegans using LC-MS, I have discovered the biosynthetic precursor, potential intermediates and enzymes required for RQ synthesis and its regulation.
An Experimental Study of the Nose Landing Gear Noise with Emphasis on the Steering Actuators, Torque Link and Tow Hook
Keywords: aeroacoustics
beamforming
landing gear
noise
steering
torque link

Aeroacoustic and Particle Image Velocimetry (PIV) tests were conducted on the simplified model of a nose landing gear that permitted independent additions of the tow hook, torque link and steering systems. Tow hook was found to suppress low-frequency overhead noise originating from the axle-strut region. Tests involving torque links mounted upstream and downstream of the strut with varying arm separation distances showed that upstream mounting induces: i) prominent low-frequency noise in the sideline direction, and ii) higher broadband noise in the overhead and sideline directions when the torque link arms are close. Increasing the separation between the torque link arms decreased the broadband noise contribution of the upstream mounted torque links to levels of those mounted downstream. The steering actuator orientation is shown to be crucial for the acoustic response of the gear. Steering actuators placed nearly perpendicular to the freestream flow were found to generate the quietest responses.
Measuring Foot Clearance on Outdoor Walkways
Keywords: computer vision
falls
gait
Minimum foot clearance
outdoor
tripping

Over half of older adult falls are caused by tripping. Many of these trips are likely due to obstacles present on walkways that put older adults at risk because of their low foot clearances during gait. The Parallel Laser Array Recording (PLAR) system was developed for measuring foot clearance values. The PLAR system was designed to be positioned at ground level next to outdoor walkways to efficiently collect sagittal plane videos of many pedestrians’ feet. The objective of this project was to develop a computer vision algorithm for analyzing PLAR video to estimate foot clearance values and evaluate the accuracy of the algorithm by comparing to the current time-consuming manual analysis process. The developed algorithm was found to have good accuracy with an RMS error of 3.70 mm when compared to a manual PLAR video analysis with RMS error of 2.32 mm.