VictorJuiz/thesis huggingface dataset:
Characteristics, Engagement and Academic Performance of First-year Nursing Students in Selected Ontario Universities

With an aging population nationally, nursing programs have struggled to meet the demand for nurses in our healthcare system. Student attrition remains high at 28% within the first two years of the Baccalaureate nursing programs. In order to meet healthcare system demand, nursing programs need to ensure that students persist, graduate, and are academically successful on the national examination. As a first step in student success, one needs to identify effective educational practices in first-year nursing programs that are associated with student engagement within the Canadian context. Extensive research in the U.S. has examined educational practices and student engagement. However, few national or international studies examined nursing student characteristics and engagement and student success. This study examined the extent to which first-year nursing students are engaged in effective educational practices and any relationships between student demographic, external, academic, social, and institutional variables, and student engagement. A descriptive correlational design was used to conduct a secondary analysis of pre-existing 2008 National Survey of Student Engagement (NSSE) data from nursing students in 13 Ontario Universities. Descriptive statistics were computed to examine student characteristics and the distribution of NSSE benchmark scores. Step-wise multiple regression analysis was used to identify relationships between predictor variables and student engagement and academic performance (grade point average). The results identified several significant predictors of first-year nursing student engagement including age, ethnicity, hours spent preparing for class per week, grade point average, hours per week spent participating in cocurricular activities, participating in physical fitness activities, and institutional size. Being a first-generation student and age were significant predictors of academic performance for first-year nursing students. The findings provide insight into some of the drivers of engagement in first-year nursing education and may also inform policy and practice for improving nursing student engagement and, ultimately, graduation rates.

Keywords: Baccalaureate nursing program
NSSE
Nursing education
Ontario nursing
Student Engagement
student success
Advisor: Dietsche, Peter
Design of Ultra-wideband Reflectors

It is well-known that reflectarrays typically have a narrow bandwidth which is commonly attributed to the resonant nature of the antenna elements used and the narrow bandwidth of the phase shifting networks used. Typical approaches to increase the bandwidth include the use of true-time-delay (TTD) devices, coupling multiple resonances together, stacking multiple layer of scatterers or the use of numerical optimization techniques. While these approaches have been shown to improve the bandwidth of reflectarrays, the upper bound remains at approximately 40 in fractional bandwidth. This thesis investigates how ultra-wideband reflectors can be designed using novel approaches going beyond the conventional approaches listed above. Specifically, we investigate two new methods to design reflectarrays. In the first method, the reflector is designed as a Transformation Optics (TO) device and in the second method, the reflector is designed as a metasurface. The TO method amounts to manipulating of electromagnetic waves using an appropriate set of material parameters such that the wave propagation inside the material behaves in a desired manner. We use TO as a means to design an ultra-wideband reflector and draw insights into the practical considerations associated with designing such a reflector. In the second method, we design a reflectarray as a metasurface. Traditionally, reflectarrays are considered to be an array of individual antenna elements with no surface properties typically defined. A metasurface often has homogenized surface properties such as surface impedance and admittance which are realized by sub-wavelength elements that make up the reflector. A novel method to design ultra-wideband reflector using a metasurface is derived from first principles and it is shown that the designed reflector exhibits excellent characteristics over a very wide band of frequencies. The advantages and disadvantages of the reflectors designed using each of these two methods are discussed. A comparison of our metasurface is made to a state-of-the-art wideband reflectarray.

Keywords: antenna array
metasurface
reflectarray
wideband reflector
Advisor: Hum, Sean V
Three Essays on the Behavioural Economics of Saving for Retirement

This thesis comprises three chapters that investigate, from a behavioural economics perspective, how individuals prepare financially for retirement. In Chapter 1, I investigate whether a savings 'nudge' is a viable mechanism to help people overcome knowledge barriers associated with saving for retirement. Using administrative tax records from Canada, I begin by estimating whether a nudge in workplace pensions increases net savings or induces workers to reduce contributions in other accounts. I find that a $1 increase in employer contributions crowds out other savings by $0.50. Hence, a nudge raises savings on average but many workers actively respond to it, which leads me to consider underlying heterogeneity in more detail. Specifically, I examine the effects of education on savings adjustments to a nudge and savings behaviour, using compulsory schooling reforms for identification. I find that workers with low education save inadequately for retirement on their own but benefit from a nudge by remaining passive, whereas those with high education are forward-looking and respond to the distortion by re-optimizing savings across accounts. These results indicate that a nudge likely increases consumer welfare in practice. In Chapter 2, I analyze the welfare implications of savings nudges when agents face subjective uncertainty about how to prepare adequately for retirement, but can mitigate this risk through endogenous information acquisition. I show that whether an optimal nudge increases or decreases individuals' savings levels depends on whether they initially under- or over-save due to their subjective uncertainty. Moreover, policies targeting human capital formation are a viable substitute for nudging, a result that policy-makers should consider when deciding on socially efficient programs for encouraging individuals to save. In Chapter 3, I examine the effect of withholding taxes on pre-retirement withdrawals from retirement savings account. Specifically, I estimate the elasticity of withdrawals to the net-of-withholding tax rate to be 1.5 for prime-aged savers. This finding suggests withholding taxes discourage pre-retirement withdrawals, serving as a de facto savings commitment device. Hence, individuals sometimes struggle to save adequately for retirement for reasons that are not well-explained by rational agency. I show that theories of present-biased preferences provide a better explanation.

Advisor: McMillan, Robert
Tutoring Writing, Transmitting Culture: Investigating Tutors' and Students' Beliefs about Good Writing and a Writer's Voice in an Afterschool Literacy Program

Using an ethnographic case study approach, this thesis investigates what multilingual adolescent writers and their adult tutors in an afterschool literacy program believe about good writing and a writerâ s voice, and how their beliefs about writing and voice both reflect particular linguistic and cultural values and shape attitudes towards language use, the writer, and writing development. Grounding the research in social constructivism (Vygotsky, 1980, 1986) and theories of language socialization (Duff, 2007a; Schieffelin Ochs, 1986), legitimate peripheral participation (Lave Wenger, 1991), and symbolic capital (Bourdieu, 1991, 2006), I addressed the following three questions: 1) What do tutors and students believe about good writing and a writer's voice? 2) How do tutors conceptualize their identities, purposes, and actions in responding to students' writing and voice in this context? and 3) In what ways do students see their tutoring sessions contributing to their overall development as writers? I observed 4 writing tutors and 5 of their students for 4 months, triangulating data that included observing and digitally recording the tutoring sessions; conducting semi-structured interviews and stimulated recalls with the participants; and collecting print-based materials produced by the participants. The findings show (a) that participants considered good writing as a moral imperative and that they saw good writing and voice both as interconnected and as something that produced writer capital; (b) that volunteers constructed an ad hoc tutoring identity marshaled from personal and professional experiences to tutor effectively; (c) that learning to write was a transformative, bidirectional undertaking with experts (tutors) being affected as much as novices (students); and (d) that students exhibited strong convictions over what makes an ideal writing tutor. These four observations suggest that writing and tutoring writing transmit cultural knowledge, language values, and principles of appropriate verbal and physical conduct.

Keywords: adolescent
literacy
tutoring
voice
writing
Advisor: Cumming, Alister
Bisimulation-based Structural Summaries of Large Graphs

With an increasing number of heterogeneous entity descriptions available as large graphs that grow to millions of nodes and billions of edges, it is a challenge to understand, explore, and query these large graphs. Bisimulation-based structural summaries have often been used as a compact representation of the dataset that can improve query performance. However, current bisimulation summary construction techniques for large graphs do not scale and do not facilitate the use of summaries within existing systems. We address these challenges with three contributions. First, we describe bisimulation summary construction techniques for large graphs that leverage a novel singleton optimization which drastically reduces construction time. Second, we show how structural summaries can be used to improve query performance within existing RDF systems. Third, we give an ontology for describing structural summaries as RDF that enables their use and verification with existing RDF tools. Our work also demonstrates that the S+EPPs system, built on top of existing RDF processors, is an efficient, scalable, and flexible approach to exploring and querying large graphs using bisimulation-based structural summaries.

Keywords: databases
graph
multi-core
parallel
RDF
summary
Advisor: Consens, Mariano P
Gr端ninger, Michael
Quantitatively Assessing the Role of Higher Education in Global Sustainability

Three analytical methods are used to examine three primary questions to address an observed scarcity of literature that quantitatively and empirically assesses the role of higher education in global sustainability. Linear regression is used to assess correlations between institutional environmental impacts and campus initiatives; environmentally-extended input-output analysis is used to assess the global operational footprint of higher education; and the IPAT framework and integrated assessment modeling are used to assess the influence of higher education on global systems. Despite limitations - most notably that current data availability impedes the isolation of higher education from education more broadly - the results support the following conclusions. 1) There are no meaningful correlations between campus sustainability initiatives and direct environmental impacts, though many initiatives are admittedly not aimed at reducing direct impacts. 2) The fraction of overall human ecological footprint attributable to higher education is too minor for its management to play a transformative role in achieving global sustainability, but managing it to lead by example could be more so. 3) Higher education influences global sustainability most significantly by contributing to the education driven fertility mechanism, and possibly by promoting technological change, though the magnitude and exact mechanisms of the latter relationship are uncertain.

Keywords: Environmentally extended input output modeling
Industrial ecology
Integrated assessment modeling
Sustainability
Sustainability in higher education
Sustainable development
Advisor: Kennedy, Christopher
Development and Characterization of an Extractive-based Bio-epoxy Resin from Beetle-infested Lodgepole Pine (Pinus contorta var. latifolia) Bark

Deriving chemicals from renewable feedstock has become a necessity to reduce dependency on petroleum, which release carbon dioxide when burned and aggravate the global warming and ocean acidification. This work offers a potential alternative - bark extractives based epoxy resin - to petro-based conventional epoxy. Our results showed successful epoxidation of bark extractives after reaction with epichlorohydrin. The newly synthesized epoxy (E-epoxy) can replace 50% of petroleum-based epoxy (P-epoxy) and the blend system displayed thermal stability and tensile strength comparable to neat P-epoxy, which demonstrates a great promise in using bark extractives as a substitute for bisphenol A (BPA). An examination of reaction parameters showed that the E-epoxy monomer can be synthesized with high yield and reactivity using spray-dried extractives as substrates, a dioxane/water combination as solvent, and tetrabutylammonium hydroxide as the ring-opening catalyst. An examination of numerical parameters showed the maximum yield with minimum epoxy equivalent weight was achieved after 4.5 hours reaction time with sodium hydroxide to hydroxyl value molar ratio of 3.4 at a reaction temperature of 80 °C. The thermal properties of E-epoxy were studied using TGA, FTIR, and Py-GC/MS, and a new thermal degradation mechanism was proposed. Additionally, nanocellulose fibres (NCFs) were incorporated to enhance E-epoxy’s mechanical performance. Based on an adjusted curing schedule, an E-epoxy/P-epoxy/NCFs composite with high strength, ductility, thermal stability, and sustainability was developed. With 10% E-epoxy, the toughness of neat epoxy resins improved 84 %; after incorporating NCFs, the tensile strength and modulus of composites increased approximately two- and four-fold, respectively. The maximum degradation peak of the composites was 24 °C higher than for neat epoxy resins. Overall, bark extractives exhibit great promise to replace petro-based BPA; incorporating NCFs into E-epoxy/P-epoxy blending system is an effective method to develop a strong and sustainable bio-nanocomposite.

Keywords: Bio-based epoxy
Bisphenol a
Curing
Epichlorohydrin
Nanocellulose fibres
Tree bark
Advisor: Sain, Mohini
Yan, Ning
From Farm to Firm: Canadian Tobacco c. 1860-1950

This dissertation examines the transformation of Canadian tobacco cultivation from its roots in local markets and personal consumption to a multi-million dollar concern featuring corporate plantations and multi-acre tobacco farms. It focuses on how tools of agricultural modernization— abstraction, expertise, experimentation, fertilization, government policy, land ownership, and marketing associations—produced unanticipated challenges that complicated any linear development of tobacco cultivation. The dissertation places everyday experiences of tobacco cultivation alongside the broader sweep of agricultural modernization to argue that the deployment of the tools of modernization produced new limitations over expert control of the environment and markets. The dissertation considers cultivation in Ontario, Quebec, and British Columbia, and includes moments of rapid expansion, such as the rise of the flue-cured tobacco “New Belt” in Norfolk and Elgin counties during the late 1920s, and instances of gradual failure, like efforts to encourage commercial tobacco in the Okanagan and Sumas Valley regions of B.C. Various farmer organizations and cooperatives feature in the exploration of the responses and initiative of farmers to the evolving requirements of tobacco companies for their raw material. The role of both federal and provincial government officials also receives considerable attention, as they promoted modern, commercial-orientated tobacco cultivation while attempting to remain an intermediary force between farmers and corporations. The records of the federal Tobacco Division and various government investigations collectively demonstrate that this position was not always tenable, as the government would find itself drawn into fierce disputes over farm prices and the monopolistic character of Imperial Tobacco. These disputes illustrate how modernization produced instabilities even as it improved farm revenues. Collectively, this dissertation’s consideration of farm work, environmental change, and markets demonstrate how the possibilities of agricultural innovation produced their own tensions and limitations that are fundamental to understanding the lived experience of capitalism and modernization in rural Canada.

Keywords: Environmental History
History of Capitalism
Modernity and Expertise
Rural History
Social History
Tobacco
Advisor: Penfold, Steve
Ultrasound-mediated S100A6 Gene Therapy Ameliorates Myocardial Ischemia/Reperfusion (I/R) Injury

Abstract New therapies targeting myocardial ischemia/reperfusion (I/R) injury are key to averting the adverse remodeling process and subsequent heart failure (HF) post myocardial infarction (MI). S100A6 is a member of the superfamily of EF-hand Ca2+-binding proteins that modulate many key pathways involved in myocardial I/R injury and adverse left ventricular remodeling including cardiomyocyte apoptosis and hypertrophy. Methods and Results S100A6 overexpression improved calcium transients and protected against apoptosis induced by hypoxia-reoxygenation via enhanced calcineurin activity, while knockdown of S100A6 had detrimental effects in rat neonatal cardiomyocytes, in vitro. Moreover, S100A6 overexpressing HUVECs show enhanced tube formation and augmented migration as markers of angiogenesis in vitro. In a rat model of myocardial I/R, S100A6 expression is up-regulated in the infarct and peri-infarct regions of the left ventricle (LV) following myocardial I/R injury but occurs simultaneous or just after the peak of apoptosis and LV functional deterioration. Ultrasound-targeted microbubble destruction (UTMD) delivery of hS100A6-plasmid prior to I/R yields a survival advantage, improves LV systolic function and myocardial perfusion, attenuates cardiac hypertrophy and reduces infarct size through prevention of apoptosis and necrosis and enhancement of calcium handing post myocardial I/R injury, in vivo. Finally, UTMD delivery of hS100A6-minicircle (MC) immediately after I/R injury yields similar therapeutic benefits on reduction of infarct size, improved LV systolic function and myocardial perfusion, as compared to control and empty minicircle UTMD. Conclusion The present study is the first to demonstrate the therapeutic benefits of targeted hS100A6 gene delivery in the setting of cardiac I/R injury, resulting in a significant improvement in LV function, a reduction in infarct size and prevention of adverse LV remodeling. Gene therapy by UTMD of S100A6 holds promise as adjunctive therapy to primary percutaneous coronary intervention to help ameliorate ischemia/reperfusion injury.

Keywords: Myocardial Ischemia/Reperfusion Injury
S100A6
Ultrasound-Mediated Gene Delivery
Advisor: Leong-Poi, Howard
A New Class of Modular Multilevel DC/DC Converters for HVDC Systems

This thesis develops a new class of modular multilevel dc/dc converters, termed the DC-MMC, that can be deployed to interconnect HVDC networks of different or similar voltage levels. Advanced operating features include buck/boost functionality and bidirectional dc fault blocking analogous to a dc circuit breaker. A key advantage of the DC-MMC is that it eliminates the full-rated intermediate ac conversion stage traditionally employed by modular multilevel converter (MMC) based two-stage dc/dc converters, i.e. dc/ac-ac/dc conversion. This is enabled by a new single-stage bidirectional dc/dc conversion process that requires only a fraction of the dc power throughput to be internally circulated as ac power. In comparison to state-of-the-art MMC based two-stage dc/dc conversion, the DC-MMC enables up to a 50\% reduction in total semiconductor expenditure and total capacitive energy storage requirements, translating to commensurate savings in converter capital cost and operating losses. The DC-MMC principle of operation is validated via simulation of a comprehensive switched model in PLECS. To gain deeper insight into DC-MMC dynamics and internal power transfer mechanisms, this thesis exploits the use of dynamic phasors to accommodate the multiple frequency components that exist at steady-state. Large-signal and small-signal time-invariant dynamic phasor models are derived. The large-signal phasor model enables: 1) solving for the full steady-state solution of the DC-MMC under arbitrary loading, and 2) evaluation of DC-MMC open-loop stability via eigenvalue analysis. Based on the small-signal phasor model, a dynamic controller suitable for dc network applications is proposed that regulates output power while ensuring individual capacitor voltages remain balanced. The developed analytical models and dynamic controls are validated by simulation. Bidirectional dc fault blocking capability is also confirmed by simulation. Experimental results for a 4 kW prototype validate the single-stage dc/dc conversion process for both step-down and step-up operating modes.

Keywords: Control
Converters
DC/DC Conversion
HVDC Transmission
Modeling
Power Electronics
Advisor: Lehn, Peter W