VictorJuiz/thesis huggingface dataset:
Phylogenetic, Ontogenetic, and Functional Implications of Hominoid Mandibular Corpus Shape Variation

Mandibular fragments are among the most commonly preserved elements in the primate fossil record. These specimens are often studied through linear measurements of mandibular corpus height and breadth, which are used to calculate mandibular robusticity (MR). Presently, the significance of mandibular corpus variation in both living and fossil hominoids remains unclear. Here, three separate analyses are conducted to develop and evaluate an alternative method to quantify hominoid mandibular corpus shape and to investigate the dietary, phylogenetic and ontogenetic significance of hominoid mandibular corpus shape variation in order to help interpret corpus shape variation in the primate fossil record. These analyses use landmarks and semilandmarks to capture the shape of the outline of the mandibular corpus in cross-section in a sample of extant great apes, corporal cortical bone distribution (CBD) in a sample of extant and fossil hominoids, and to assess ontogenetic changes in corpus shape and the relationship between these changes and molar crypt length, breadth and height in a sample of extant hominoids. These results show that quantification and comparison of the shape mandibular corpus in cross-section is a preferred alternative to MR in studying the hominoid fossil record. Additionally, extant hominoids are found to have significant CBD shape differences that are phylogenetically significant and do not match morphological predictions based on diet. Investigation into ontogenetic changes in corpus shape shows clear differences in growth patterns among all three species prior to the emergence of M1, and finds a significant covariance between molar crypt form and corpus shape during the developmental stage marked by the emergence of M1. This research is significant because it provides support for the hypothesis that hominoid mandibular corpus shape is influenced by the development of the molars in their crypts during development. These results also indicate that both corpus shape and corporal CBD shape are taxonomically and phylogenetically significant and do not match morphological predications based on diet in hominoids. Additionally, this research shows that quantification and comparison of the outline of the mandibular corpus is a preferred alternative to MR in studying the hominoid fossil record.

Keywords: Biological Integration
Evolution
Geometric Morphometrics
Mandibular Growth
Mandibular Shape
Primate Ontogeny
Advisor: Begun, David R
Neural Circuitry of Upper Airway Respiratory Plasticity: Identifying the Neural Circuitry Underlying Long-term Facilitation of Inspiratory Genioglossus Motor Output

The respiratory system is highly adaptive and can change its behaviour to provide protective responses in face of repeated respiratory challenges. Elucidating the role of how neurons and neural circuits mediate these responses can open new treatments for those that cannot adapt. Respiratory long-term facilitation (LTF) is one form of adaptation that can increase genioglossus motor output, potentially providing a means to mitigate respiratory disorders such as obstructive sleep apnea. I examined the neural circuitry that underlies this form of respiratory motor plasticity and I identified: (1) the neural circuit that mediates respiratory LTF of inspiratory genioglossus motor output, (2) a novel trigger that elicits LTF without directly or indirectly modulating the respiratory feedback systems, and (3) the neurotransmitter(s) that are essential to the manifestation of respiratory motor plasticity of genioglossus motor output. Using tract-tracing, immunohistochemical and pharmacological approaches, I have identified a tripartite circuit connecting the nucleus tractus solitarius (NTS), the locus coeruleus (LC), and the hypoglossal motor nuclei (XII) that are individually critical to the elicitation of LTF. I also employed a series of optogenetic approaches to identify the LC as a trigger that can elicit LTF following intermittent stimulation of the LC alone. Lastly, I identified noradrenaline, released by the LC and acting on α1-adrenergic receptors at the hypoglossal motor nuclei, to be the key neurotransmitter-receptor system that gates the expression of respiratory motor plasticity. These findings provide direction and novel therapeutic targets to treat respiratory disorders such as obstructive sleep apnea.

Keywords: Genioglossus
Hypoglossal
Locus coeruleus
Long-term facilitation
Neural plasticity
Optogenetics
Advisor: Peever, John H
Enhancing Steel Cleanliness in Tundishes by applying Physical and Mathematical Modeling

The tundish, being the last vessel which stores steel in liquid state, provides the final opportunity to enhance its quality. Hence, it must be ensured that the tundish acts as a refiner rather than a contaminator. It has been noticed that reoxidation of liquid steel from ambient air aspiration through the ladle slide gate, can seriously degrade the steel quality. As a preventive measure, the reoxidation-prone region is flooded with an inert gas such as argon to prevent aspiration of air. However, some argon bubbles themselves can get aspirated into the liquid steel stream flowing from the ladle into the tundish. Thus, an upwelling buoyant gas-liquid plume is formed, which sweeps off the overlying slag layer and subsequently gives rise to an exposed region of molten steel, known as the Tundish Open Eye (TOE). In the present work, TOE formation in two different tundish systems viz., a 12-tonne four-strand billet caster tundish, and a 63-tonne two-strand slab caster tundish, has been studied. A holistic approach, including plant trials, physical modeling, mathematical modeling, dimensional analysis and mechanistic modeling, has been taken up to investigate the TOE phenomenon. Additionally, the effects of eccentric open eye formation and non-isothermal flows on steel quality were also analyzed. Plant trials were carried out to study the variation of TOE size by using high definition (HD) videography. The total oxygen and inclusion analyses were carried out using the LECO and ASPEX techniques respectively. The mathematical modeling for both the water/oil/air system and liquid steel/slag/argon gas system was performed using the Volume of Fluid (VOF) method, and discrete phase method (DPM), coupled with the standard k-ε turbulence model. The mathematical model was validated with the experimental results from physical modeling and plant trials. A mechanism of formation of the TOEs and emulsification of the slag layer was proposed based on the results. Critical argon gas flow rates were also determined, for which there is negligible or no TOE formation. Operating under these flow rates ensure better steel quality due to prevention of reoxidation through TOE.

Keywords: Mathematical modeling
Open eye
Reoxidation
Steel cleanliness
Steel/slag/argon/inclusion interation
Tundish metallurgy
Advisor: Chattopadhyay, Kinnor
Impact of Fuel Variability and Operating Parameters on Biomass Boiler Performance

Biomass boilers provide up to one-third of the energy requirement in pulp and paper mills by burning hog fuel, which is a mixture of wood-waste available at the mill site. The quality of this fuel varies significantly depending on its source and storage conditions. This fuel variability often causes biomass boiler operation to be unstable and unpredictable. This study consists of two parts: the first part investigates the impact of fuel variability on combustion and develops means for mitigating these impacts to achieve stable boiler operation. The second part identifies the most influential parameter in boiler operation using multivariate analysis, and develops a predictive statistical model for optimization of biomass boiler thermal performance. In the first part, wood species are differentiated by their initial particle density. For all wood species examined, particle density decreases throughout the combustion process but at different rates depending on the combustion stage. During the devolatilization stage, the density decreases significantly as a result of rapid mass loss. This sharp decrease causes particles to be light enough to be entrained and/or be lifted off from the grate by the flue gas. An analytical model is then developed to calculate particle entrainment velocity, and to determine whether a particle is entrained and if so, how much unburned mass is left upon entrainment. In the second part, multivariate analysis is used to identify the most important parameters in boiler operation. The results show that moisture content is the most influential parameter and a soft sensor is consequently developed to estimate the feedstock moisture content from other parameters. A predictive Partial Least Square (PLS) model is built to predict the thermal performance of a boiler in real-time and to determine the contributing factors to process upsets. In practical applications, the entrainment model is used for fuel preparation and sizing to reduce particle entrainment. The PLS model, along with the moisture content soft sensor, can be used for process monitoring providing additional insights into causes of process variability.

Keywords: Biomass Boiler
Biomass Combustion
Energy Optimization
Hog Fuel
Pulp and Paper
Wood Waste
Advisor: Tran, Honghi
Jones, Andrew
Resistances against Hydropower Projects as Place-based Struggles: The Case of Artvin, Turkey

The dissertation examines the implications of place-based action for a rethinking of democratic politics. The research is based on the struggles against hydropower projects in Artvin, a small city in the Black Sea Region of Turkey. The dissertation traces the effects of the dams as spatial interventions in the region based on the accounts of the inhabitants, field observations, official reports, and academic articles; it maps the institutional structures that enable these spatial interventions and reveals ways citizens challenge these institutional structures. The dissertation offers a phenomenological approach as an important addition to social constructivist approaches to understanding the struggles against the run-of-the-river type hydropower projects in the region. Social constructivist approaches to place-based struggles have been significant in unpacking the power dynamics within which spatial interventions are made possible and are resisted. These approaches evaluated place-based struggles based on their handling of heterogeneity and difference, their potential in dismantling of capitalism, their ability to articulate their problems in more structural terms and their ability to be extroverted and situate themselves in broader networks. Phenomenological approaches enable us to articulate the emphasis these struggles put on the significance of “implacement” as a social and physical experience for living beings. The dissertation argues that the anti-hydropower struggles in Turkey—through their emphasis on protecting “life spaces”— underlined a form of placial ethics. “Life spaces” encompassed both human networks of relationships and their embeddedness in the entire eco-system. This placial ethics challenged the existing cost-benefit analysis and redefined the destruction of landscape as a collective loss. This ethics-based politics rendered participatory collective decision-making imperative for spatial interventions and required prioritization of politics of place over partisan politics. The politics aimed at protecting life space thus redefines the nature of interests at stake as well as the nature of democratic participation.

Keywords: citizenship
dams
democracy
ethics
place
social movements
Advisor: Nedelsky, Jennifer
Surface Engineered Sponges Enable Oily Wastewater Remediation and Residual Oil Recovery

In the US, steam-¬based oil extraction processes generate over 15 billion liters of emulsified oil contaminated wastewater annually. For sustainability, these effluents need to be remediated and/or recycled. However, the complex properties (pH, dissolved salts, and high temperature) of effluents pose challenges for removal of oil microdroplets removal using current separation methods. This thesis developed a new process to selectively recover crude oil microdroplets from wastewater using inexpensive sponges. This process synergistically uses sponge surface properties and pre-existing ionic and thermal energies of the wastewater to achieve 95-99% oil removal efficacy from wastewater. First, an acid-base polymeric sponge was applied to remove crude oil microdroplets from water. In acidic or basic environments, acid-base polymers acquire surface charge due to protonation or dissociation of surface functional groups. This property is invoked to adsorb crude oil microdroplets from water using a polyester polyurethane sponge. Using the surface charge of the sponge and oil droplets, the solution pH (5.6) for 99% oil removal efficacy was predicted and verified through adsorption experiments. The droplet adsorption onto the sponge was governed by physisorption, and the driving forces were attributed to electrostatic attraction and Lifshitz-van der Waals forces. The sponge was regenerated and reused multiple times by mechanical compression. Next, to remove oil microdroplets from water at broad pH conditions, an innovative surface engineered sponge (SEnS) was designed by combining surface chemistry, surface charge, roughness, and surface energy. Under all pH conditions, the SEnS rapidly adsorbed oil microdroplets with 95-99% removal efficiency predominantly by electrostatic attraction and Lifshitz-van der Waals forces. Furthermore, at the best pH value, 92% of the oil was adsorbed within 10 min due to synergistic charge attraction. The adsorbed oil was recovered by rinsing with a diluent while the cleaned SEnS was reused multiple times for oil adsorption. Subsequently, crude oil is recovered from the diluent using distillation. Due to the process efficacy, sponge reuse, and oil recovery, this adsorptive-recovery method using sponges demonstrates great potential for the industrial oil recovery from wastewater. Furthermore, this work lays foundation for the development of new SEnS with the potential to revolutionize water treatment technologies.

Keywords: Adsorption
Crude Oil
Crude Oil Recovery
Nanomaterials
Sponge
Wastewater Remedition
Advisor: Park, Chul B
Bilton, Amy M
Subjugation and Resistance in Older Gay Men's Health Care Experiences

The scholarship on aging among lesbian, gay, bisexual, transgender, and queer (LGBTQ) adults has, in recent years, experienced unprecedented growth. Despite this emerging body of literature, research on older gay men’s health care experiences remains limited. This qualitative study, which is framed theoretically by Foucauldian governmentality and intersectionality, and informed methodologically by a poststructuralist approach to grounded theory known as situational analysis, attempts to address this gap in the literature. Specifically, drawing on interviews with 27 Toronto-based gay men ages 50 and over, 16 of whom reported being HIV-positive at the time of recruitment, the study offers insight on the health care experiences of older gay men. More specifically, the study highlights processes of subjugation and resistance reflected in the accounts of the participants. Chapter 1 provides a critical review of the literature, highlights the role of Foucauldian governmentality and intersectionality in situating the study theoretically, and outlines the study’s research design. Chapter 2 contains an overview of the study’s key findings, which specifically delineate how sociohistorically significant discursive forces rooted in homophobia and HIV stigma, older gay men’s interpretations of medical practices, as well as institutional constructions of gay aging bodies, together reflect the role of the HIV/AIDS epidemic in shaping older gay men’s subjugation and resistance across health settings. Drawing on the study’s insights, and the centrality of Foucauldian governmentality in supporting the conceptualization of these findings, chapter 3 examines the utility of this theoretical framework in guiding and enriching qualitative studies informed by situational analysis. Chapter 4 utilizes the accounts of this study’s HIV-positive participants to identify the health care and social service needs of this population, and incorporates an intersectional lens to conceptualize variations in the service priorities of this group along dimensions of difference such as socioeconomic status, ability, and race. Finally, chapter 5 concludes with a discussion of the study’s contributions to substantive and theoretical bodies of scholarship, and an overview of the inquiry’s implications for policy and practice in the area of gay aging.

Keywords: Aging
Foucault
Gay Men
Grounded Theory
Health Care
HIV
Advisor: Ross, Lori E.
Exploring Methodologic Challenges in the Conduct of Patient-preference Studies in Obstetrics

Background: Clinical decision analysis (CDA) and model-based economic evaluations (EE) are used to inform clinical practice, funding recommendations and health policy. These models require patient-preferences for health-states. Obstetrics, which involves two intricately-related individuals - mother and fetus - who often exhibit competing interests, makes elicitation of patient-preferences challenging. Aims and objectives: To inform best practices on obtaining and using patient-preferences in obstetrics. Methods: We first conducted a systematic review of CDA studies to understand how research methods have been adapted to the mother-fetus dyad especially regarding incorporation of patient-preferences. We followed this by another systematic review to inform optimal research methods for conducting patient-preference studies in obstetrics while creating a repository of preference values for pregnancy-related health states. We used information from these studies to design and conduct a cross-sectional study eliciting preferences for health-states related to anticoagulant use in pregnancy. We compared three methods – visual analogue scale (VAS), time trade-off (TTO) and standard gamble (SG), and obtained preference values through individual and shared interviews with pregnant women and family members. Results: Our first review (77 studies) showed that despite long-term implications of obstetric decisions, studies frequently did not consider lifetime horizons and patient-preferences for outcomes related to mother and offspring, and failed to adhere to guidelines regarding conduct and reporting. The second review (37 studies, median 125 participants) found inconsistencies in choice of valuation methods, anchors and sample size specifications, and knowledge gaps with regard to the role of family members in decision-making. The third study (57 pregnant women and 43 family members) showed that preference values obtained through shared interviews were closer to those of the family member and that VAS and TTO had greater differences between health-state valuations relative to the SG. Conclusions: In obstetrics, consideration should be given to involving family members while obtaining preferences for combined maternal-fetal health-states. The SG seemed most appropriate for this study. Implications: Our work informs methods regarding conduct of CDA and patient-preference studies in obstetrics, contributes to clinical decision-making and delineates a plan for future research that will standardize conduct and reporting of patient-preference studies.

Keywords: Maternal-fetal health states
Mother-fetus dyad
Obstetrics
Patient-preferences
Advisor: Sander, Beate
Murphy, Kellie
Life, Irrupted: An Occupational Perspective on the Lives of Women Who Experienced Sexual Assault While at University

Although sexual assault that occurs during university is known to have numerous significant consequences, many are believed to remain “hidden.” This dissertation research employed an occupational perspective to provide a more fulsome examination of the aftermath of sexual assault that occurs during university. Three distinct studies, yielding four manuscripts, were conducted. First, a review of the sexual assault literature was carried out. Findings suggested a clear but narrowly examined occupational aftermath of sexual assault. Next, women’s experiences of everyday living in the aftermath of sexual assault were explored through different forms of narrative: (a) memoirs written by women who had experienced sexual assault during university, and (b) interviews with women who had experienced sexual assault during university. These studies suggested an extensive occupational aftermath of sexual assault. Together, the findings of this dissertation research make five unique contributions to the sexual assault and occupational science literature. First, the findings suggest that an occupational perspective may be used to uncover some of the hidden consequences of sexual assault, specifically those related to human occupation. Second, the findings suggest that sexual assault that occurs during university is occupational life-altering. Sexual assault was found to have significant, widespread, and lasting consequences for women’s daily occupations, as well as for their occupational trajectories. Third, the findings suggest that sexual assault alters women’s occupational lives in ways that at once follow a pattern and are particular to the individual. Although broad patterns in changes to women’s occupations were identified, occupational choice and engagement were found to be idiosyncratic in the aftermath of sexual assault during university. Fourth, the findings suggest that the alterations produced by sexual assault necessitate the (re)building of one’s occupational life and self through conscious engagement in occupation. Last, the findings are suggestive of a model of occupational response following major life disruption. Further research is warranted to continue to develop an expanded understanding of what everyday living looks like after life disruption beyond sexual assault that occurs during university.

Keywords: Daily activity
Occupational science
Rape
Advisor: Polatajko, Helene J
Du Mont, Janice
Environmental Teacher Leaders: Motivation, Supports and Barriers

In today’s age of mandated school reforms, it would seem advantageous for principals to share school leadership with teachers. Yet teacher leadership is an area that is still emerging and these skilled professionals may be overlooked and underutilized, to the detriment of school success. This study aims to gain a deeper understanding of the motivating factors behind why environmental teachers choose to take on a leadership role and what conditions hinder or support them in this role. This study, using a sequential explanatory mixed methods design, consists of two phases: a survey completed by Ontario EcoSchools lead teachers, followed by semi-structured interviews. Results show that most teacher leaders are motivated by a personal interest coupled with a desire to instil a deeper understanding of environmental issues and values in their students. Despite their passion, some teacher leaders were unsatisfied or not likely to continue in the role. Results from the Teacher Leadership School Survey indicated they felt their schools were not as supportive of teacher leadership. Even satisfied teachers cited barriers to teacher leadership which included reluctant peers, insufficient active support by the principal and obstructive school structures. Three key areas for consideration emerged: 1) Teacher leaders may lack the skills to navigate resistant school cultures, 2) Principals are key in creating enabling school structures, and 3) Teacher leadership growth requires system-wide change. These insights deepen our understanding of the phenomenon of teacher leaders, so that measures can be implemented to support their professional growth and help foster this essential role in schools.

Keywords: educational leadership
environmental teacher leaders
factors influencing teacher leadership
teacher leader motivation
teacher leadership
Advisor: Flessa, Joseph