VictorJuiz/thesis huggingface dataset:
Source Tracing of Dissolved Organic Matter (DOM) in Watersheds Using UV and Fluorescence Spectroscopy

In aquatic ecosystems, dissolved organic matter (DOM) is an important source of detrital energy on which microorganisms rely. However, its dynamics are not well understood in an ecological context. By isolating watershed sources, the work reported in this thesis has attempted to characterize the seasonal patterns of DOM in the hyporheic zone of a temperate stream and to find the likely sources that contribute to this pool of organic carbon. Hyporheic DOM characteristics described by UV spectroscopy indicated temporal rather than spatial dependence. Excitation-emission matrices (EEMs) showed that hyporheic DOM was mainly comprised of fulvic- and humic-like fluorescence with small amounts of protein-like fluorescence. Increases in dissolved organic carbon (DOC) concentrations from birch litter isolates were greater than those from cedar litter in early autumn, but less in late autumn. Although streambed biofilm was not significant in increasing DOC concentrations, it was also a source of protein-like fluorescence.

Keywords: streams
detrital energy
ecosystem ecology
spectroscopy
dissolved organic matter
carbon cycling
Advisor: Williams, D. Dudley
The ABO Polymorphism and Plasmodium Falciparum Malaria

Malaria has exerted a major selective pressure for red blood cell (RBC) polymorphisms that confer protection to severe disease. There is a predominance of blood type O in malaria endemic regions, and several lines of evidence suggest that the outcome of Plasmodium falciparum infection may be influenced by ABO blood type antigens. Based on observations that enhanced phagocytosis of infected polymorphic RBCs is associated with protection to malaria in other red cell disorders, we hypothesized that infected type O RBCs may be more efficiently cleared by the innate immune system than infected type A and B RBCs. The present work demonstrates human macrophages in vitro and murine monocytes in vivo phagocytosed P. falciparum infected O RBCs more avidly than infected A and B RBCs independent of macrophage donor blood type. This difference in clearance may confer relative resistance to severe malaria in individuals with blood type O.

Keywords: Malaria
Hematology
ABO Blood Group
Phagocytosis
Advisor: Kain, Kevin C.
In Their Own Best Interests? Textually Mapping Governmentality in the Lives of Young People without Stable Housing in Canada

Working to untangle the multiple interests and “truths” that manifest in decision-making in youth shelters, I draw on the Foucauldian perspective of governmentality as an alternative means of problematizing “youth homelessness” in Canada. Tracing interdiscursivity between levels of authority, I use critical discourse analysis to deconstruct federal and Ontario government, and Toronto youth shelter discourses. Aiming to normalize the problematic, I uncover tensions between crime control and human resource development within each level of authority. Further, usurping attention to employment and housing, mental illness and youth criminality are taking over as dominant discourses. Moreover, the discursive production of “needy” and “helping” subjectivities is serving to depoliticize and individualize institutionally structured relationships, thereby limiting the depth of citizenship permitted poor, racialized and gendered young people. Concealing ongoing neo-liberal restructuring, therapeutic community-based governance is thus justified over action to address the roots of youth homelessness.

Keywords: Poststructuralism
Governmentality
Critical Discourse Analysis
Homeless youth
Neo-liberalism
Community-based governance
Advisor: Chambon, Adrienne S.
Clinical Faculty's Activities and Outputs: An Intellectual Capital Concept Map

The purpose of this study was to explore the composition of intellectual capital (IC) by addressing the research question: What are the knowledge-based activities and outputs which comprise the IC of a university medical department? A conceptual framework was developed to highlight the importance of activities. The conceptualization of IC was further developed using concept mapping. Education administrators’ perceptions were solicited to derive IC used in a research faculty of a Canadian university. The results indicate that IC can be understood in terms of activities and outputs. Clinical faculty can be expected to engage in research and its supervision, education, obtaining qualifications, clinical and professional practice, and service. Within these categories, individual activities and outputs were not considered to be of equal importance or impact. Among seventy activities and outputs, articles in internationally refereed journals was ranked as most important, whereas teaching awards was ranked as having the most impact.

Keywords: Intellectual capital
Concept mapping
University medical department
Clinical faculty
Education administrators
Advisor: Clare, Beghtol
Producing Barrels from Bitumen: A Political Ecology of Price in Explaining the Classification of the Alberta Oil Sands as a Proven Oil Reserve

In December, 2002, the oil sands of Alberta, Canada – earlier seen as an obscure, obstacle-ridden scientific project – were for the first time included in the Oil & Gas Journal’s year-end review of worldwide oil reserves. To explain this decision, the editors of this prestigious international petroleum magazine cited the basic neoclassical economic theory of price-driven resource substitution. This thesis contends, however, that the neoclassical theory in fact explains very little of how it became possible to profitably extract petroleum from Alberta’s bitumen-saturated sands. Merging insights from resources geography on the politics of nature-based production with scholarship on calculation and classification in Science and Technology Studies, this thesis fleshes in much-needed detail and dimension to the neoclassical account by emphasizing the role of key actors and decision-makers, many within the state but also within the private sector, who have actively negotiated supply costs and pursued technological strategies for the oil sands. In doing so, it argues that market prices and supply costs are not independent objects, but are underpinned by a malleable, contingent, and profoundly political process. As evidence, this thesis draws on national and international petroleum statistics, industry publications and public relations campaigns, as well as over 80 years of archived and more contemporary government documents, in order to show that substitution between two materially different resources is rarely an independently propelled or inevitable response.

Keywords: Alberta oil sands
resources geography
oil reserves
Advisor: Prudham, W. Scott
Adverse Drug Reactions in the Emergency Department Population in Ontario: Analysis of National Ambulatory Care Reporting System and Discharge Abstract Database 2003-2007

ADR is an important public health problem which reduces quality of care patients receive and increases cost to healthcare system. Little is known about the incidence and economic burden of ADR-related ED visits and subsequent hospitalizations in Canada. This study estimated the incidence and cost of ADR-related ED visits and subsequent hospitalizations for patients (>65 years) in Ontario, and explored patient, drug and system factors associated with severe ADRs. In a population-based retrospective cohort of Ontario older adults, 7222 (0.75%) of all ED visits were ADR-related, and among these patients 21.56% were hospitalized in 2007; In 2007, the total measured cost of ADR-related visits and subsequent hospitalizations amounted to $13.6 million with the cost being $333.47 and $7528.64 per person for ED visits and subsequent hospitalizations, respectively. Severe ADRs were associated with sex, age, comorbidity, multiple drugs, multiple pharmacies, newly prescribed drugs, recent ED visit, recent hospitalization and LTC residents.

Keywords: adverse drug reaction
Advisor: Wodchis, Walter
A Comparison of the Costs of Sentinel Lymph Node Biopsy and of Axillary lymph Node Dissection in the Management of Early-stage Breast Cancer in Ontario

Objective: To complete a cost-minimization analysis (CMA) of the cost of sentinel lymph node biopsy (SLNB) and axillary lymph node dissection (ALND) in the management of early-stage breast cancer (ESBC) in a hypothetical Ontario hospital setting. Methods: Decision-analysis modeling, with a decision-tree and Markov states, was used to estimate hospital costs for the two treatment options. The model was populated with data from the literature and costs from the Ontario Case Costing Initiative, a publicly accessible, government-sponsored, costing database. Model variability and parameter uncertainty were quantified by probabilistic sensitivity analysis (PSA). Results: The SLNB treatment algorithm was cost-minimizing compared to the ALND-only treatment option. The costs of treating postoperative complications did not contribute to the incremental average cost. Conclusion: A treatment algorithm that involves SLNB as the initial axillary-staging procedure in the setting of ESBC offers a cost-savings over the ALND-only option. This result is generalizable to all Ontario hospitals.

Keywords: Sentinel lymph node biopsy
breast cancer
cost-minimization analysis
decision analysis
axillary lymph node dissection
Advisor: Coyte, Peter C.
Quan, May Lynn
Plug-and-play Digital Controllers for Scalable Low-power Switch-mode Power Supplies

The purpose of this thesis is to present a novel controller structure for scalable switch-mode power supplies targeting low power applications. The design employs masterless control, where each phase is responsible for its own control in a multiphase system. The controller is capable of automatically configuring itself to work with a single phase system or a multiphase system. The configuration process allows each controller to determine the number of phases in the system, as well as to synchronize and sequence the phases. With this architecture, the same controller design can be used in many types of applications requiring different numbers of phases, resulting in a decrease in cost and design effort. The proposed design has been verified experimentally on FPGA and IC implementations.

Advisor: Prodic, Aleksandar
Single Channel Conductance of the CaV2.2 Calcium Channel

Calcium ions (Ca2+) are admitted into presynaptic nerve terminals through voltage gated calcium channels and diffuse to bind and activate the secretory vesicle discharge mechanism. Current research favors a highly ‘modal’ organization where the release sites are activated by one or a few closely apposed channels (Stanley, 1997). To fully understand the nanophysiology of transmitter release site activation, it is necessary to determine the rate of Ca2+ flux through individual channels at normal physiological external concentrations. OBJECTIVE: To explore the relationship between CaV2.2 channel conductance and external Ca2+ across the physiological range. CONCLUSION: The conductance of the CaV2.2 channel was determined across the range of 1-100 mM [Ca2+]EXT . With 2 mM [Ca2+]EXT, the conductance was determined to be 2.76 ± 0.24 pS.

Keywords: Single-channel
Calcium
Conductance
Physiological
CaV2.2
N-type
Advisor: Stanley, Elise F.
The Relationship between Children’s, Adolescents’, and Adults’ Epistemological Development and Their Evaluation of Different Teaching Methods

This study assessed the relationship between children’s, adolescents’, and adults’ epistemological development and their evaluations of different teaching methods. Participants were presented with different teaching scenarios in which the domain (scientific or moral), nature (controversial or noncontroversial), and method (lecture or discussion) were varied to determine if this affected participants’ rating of the scenarios. Epistemological development was assessed in three domains: aesthetic, value (moral), and physical truth (science). Ninety-six participants (7–8-, 10–11-, 13–14-year-olds, and college students) were included in the study. In general, it was discovered that older participants (13-14-year-olds and college students) preferred discussion methods, while younger participants (7-8 and 10-11-year-olds) did not discriminate between lectures or discussions. However, all participants took the domain, nature, and method into consideration. Epistemological development was predictive of participants’ preference for teaching methods, but only in the value domain.

Keywords: epistemology
pedagogy
theory of mind
child development
educational psychology
Advisor: Helwig, Charles C.
Reverse Engineering of Content as a Task for Finding Usability Problems: An Evaluative Case Study using the Wikibreathe Tool for Online Creation of Asthma Action Plans

After formulating the problem and reviewing relevant research literature, a study was performed that compared reverse engineering with traditional scenario-based techniques in usability evaluation. In this case study, an online tool for creating asthma action plans was created and evaluated through questionnaires and focus groups. The tool was then tested in a controlled study using both a traditional scenario-based approach and the reverse engineering method. A group of twelve users built asthma action plans using each method in a randomized order. Results concerning usability, efficiency and the types of usability problems found were reported, along with recommendations for further research in the use of reverse engineering as a method of usability evaluation.

Keywords: Reverse Engineering
Usability
Human Factors
Asthma Action Plan
Advisor: Chignell, Mark
Increased Fixation Distance during Search among Familiar Distractors: Eve-movement Evidence of Distractor Grouping

The present study tested the hypothesis that distractor-based facilitation of visual search occurs because familiar distractors are processed and rejected in groups. We recorded participants’ eye movements during a visual search task to determine if familiar distractors were associated with an increased average distance between fixations and distractors. The study provided convergent evidence of a strong relation between search efficiency and distractor familiarity, wherein the distance between fixations and distractors increases with the efficiency of search. Further examination of eye movements suggested that the grouping of familiar distractors resulted in an efficient scanning of the search display by increasing the area of the display effectively processed during each fixation and therefore reducing the need to fixate individual distractors.

Keywords: Distractor Familiarity
Eye Movements
Advisor: Reingold, Eyal M.
Generating Miss Rate Curves with Low Overhead Using Existing Hardware

Miss Rate Curves (MRCs) for main memory have been proposed as a representation of memory utilization for use in a range of optimizations in the area of memory man- agement. Various techniques exist for their creation; however, all real-world methods of MRC generation must make trade-offs between overhead and accuracy. Proposals for new hardware techniques exist, but have yet to be implemented in actual hardware. We pro- pose the use of the Intel PEBS (Precise Event-Based Sampling) performance monitoring capability for the task of MRC generation on existing commodity hardware. We use PEBS to generate MRCs and compare them against MRCs generated through instrumentation, finding the PEBS MRCs to be good, but imperfect approximations, while keeping average PEBS overheads below 5%. We were unable to show that PEBS is better or worse than existing techniques, but believe we have succeeded in showing the promise of the use of general purpose performance monitoring hardware for this task and in motivating future research and development in this area.

Keywords: Miss Rate Curves
Hardware Performance Counters
Memory Management
Operating Systems
Advisor: Brown, Angela Demke
Stumm, Michael
Synaptic Plasticity in Basal Ganglia Output Neurons in Parkinson's Disease Patients

Parkinson’s disease (PD) is characterized by the loss of dopamine in the basal ganglia and leads to paucity of movements, rigidity of the limbs, and rest tremor. Synaptic plasticity was characterized in the substantia nigra pars reticulata (SNr), a basal ganglia output structure, in 18 PD patients undergoing implantation of deep brain stimulating electrodes. Field evoked potentials (fEPs) in SNr were measured with one microelectrode using single pulses from a second microelectrode ~ 1 mm away. High frequency stimulation (HFS – 4 trains of 2s at 100Hz) in the SNr failed to induce a lasting change in test fEPs amplitudes in patients OFF medication. Following L-Dopa, HFS induced a potentiation of the fEPs that lasted more than 150s. Our findings suggest that extrastriatal dopamine modulates activity dependent synaptic plasticity at basal ganglia output neurons. Dopamine medication state clearly impacts fEP amplitude, and the lasting nature of the increase is reminiscent of LTP-like changes, indicating that aberrant synaptic plasticity may play a role in the pathophysiology of PD.

Keywords: Parkinson's disease
substantia nigra
synaptic plasticity
basal ganglia
Advisor: Hutchison, William D.
Dostrovsky, Jonathan O.
Pharmacological Rescue of Nonsense Mutations in Rett Syndrome

Rett syndrome is a neurological condition that affects primarily girls. Approximately 40% of Rett syndrome cases arise from nonsense mutations. Several studies have shown that certain aminoglycosides can suppress some types of nonsense mutations in a context dependent manner, and allow the generation of a full length protein. It remains mostly unclear whether different nonsense mutations of MECP2 will be responsive to aminoglycoside treatment. In this study I tested whether some nonsense mutations of MECP2 seen clinically in Rett syndrome girls can be partially suppressed by aminoglycoside administration. My results show that aminoglycosides allow different mutant forms of MECP2 to be overcome in transiently transfected HEK-293 cells, but with differing levels of efficiency. Furthermore, I also show that aminoglycosides increased the prevalence of full length MeCP2 protein in a lymphocyte cell line derived from a Rett girl with R255X mutation. This study establishes the “proof of principle” that some nonsense mutations causing Rett syndrome can be suppressed by drμg treatment.

Keywords: Rett syndrome
aminoglycosides
MeCP2
Advisor: Eubanks, James
Examination of NMDA receptor subunit prevalence and distribution in crude synaptic membranes purified from a mouse model of Rett syndrome.

In this study we tested whether the prevalence or synaptic distribution of NMDA receptor subunits would be altered in the brain of the MeCP2-null mouse model of Rett syndrome. Detergent resistant membranes (DRMs) and post-synaptic densities (PSDs) were isolated from the synaptic membranes treated with TritonX-100, and resolved by sucrose density gradient centrifugation. Immunoblot analysis of the resulting density gradient fractions revealed that the relative distribution of the different NMDA receptor subunits between the DRM fractions, soluble fractions, and insoluble postsynaptic density fractions was preserved in the MeCP2-null brain. However, analysis of the overall NMDA receptor subunit prevalence within these fractions revealed a significant decrease in the expression of the NR1 and NR2A subunits, but not the NR2B subunit, in the MeCP2-null brain. The preservation of distribution of NMDAR subunits to the synaptic membranes, together with the decrease in NR1 and NR2A prevalence, suggest an imbalance in equilibrium between the mature and the immature synapses in a mouse model of Rett syndrome.

Keywords: Rett syndrome
MeCP2
epigenetics
neurodevelopment
synaptic maturation
glutamate
NMDA receptor complex
NR2A
biochemical purification of crude synaptic membranes
lipid rafts
postsynaptic density
discontinuous sucrose gradient
Advisor: Eubanks, James
A New Lower Permian trematopid (Temnospondyli: Dissorophoidea) from Richards Spur, Oklahoma

A new trematopid amphibian, Acheloma dunni, is reported based on excellently preserved cranial and postcranial elements recovered from the Lower Permian fissure fill deposits of the Dolese Brothers Co. limestone quarry near Richards Spur, Oklahoma. The new taxon is characterized by distinct lateral exposures of the palatine (l.e.p.) and ectopterygoid (l.e.e.) completely enclosed within the suborbital elements. This large, terrestrial adapted carnivore may represent the top predator of the Richards Spur assemblage. A phylogenetic analysis including 11 ingroup taxa and 54 cranial characters yielded a single most parsimonious tree, placing A. dunni within the monophyletic Trematopidae as the sister taxon to Acheloma cumminsi. Furthermore, the analysis supports including the enigmatic Ecolsonia and Actiobates within Trematopidae, forming a clade with the Upper Pennsylvanian Anconastes and the Lower Permian Tambachia. The study is the first to comprehensively analyze all valid and aberrant forms of Trematopidae within the context of broader dissorophoid phylogeny.

Keywords: Amphbiia
Tetrapoda
Olsoniformes
Trematopidae
Acheloma
Advisor: Reisz, Robert R.
SLA-Aware Adaptive Data Broadcasting in Wireless Environments

In mobile and wireless networks, data broadcasting for popular data items enables the efficient utilization of the limited wireless bandwidth. However, efficient data scheduling schemes are needed to fully exploit the benefits of data broadcasting. Towards this goal, several broadcast scheduling policies have been proposed. These existing schemes have mostly focused on either minimizing response time, or drop rate, when requests are associated with hard deadlines. The inherent inaccuracy of hard deadlines in a dynamic mobile environment motivated us to use Service Level Agreements (SLAs) where a user specifies the utility of data as a function of its arrival time. Moreover, SLAs provide the mobile user with an already familiar quality of service specification from wired environments. Hence, in this dissertation, we propose SAAB, an SLA-aware adaptive data broadcast scheduling policy for maximizing the system utility under SLA-based performance measures. To achieve this goal, SAAB considers both the characteristics of disseminated data objects as well as the SLAs associated with them. Additionally, SAAB automatically adjusts to the system workload conditions which enables it to constantly outperform existing broadcast scheduling policies.

Keywords: broadcasting
scheduler
data dissemination
wireless network
tardiness
utility
Service Level Agreement
scheduling policy
mobile environment
on-demand broadcast
push-based broadcast
QoS
Quality of Service
soft deadlines
Advisor: Amza, Cristiana
Small Signal Modeling of Resonant Controlled VSC Systems

A major issue with respect to VSC based systems is the propagation of harmonics to DC side loads due to AC voltage source unbalance. Standard dq-frame control techniques currently utilized offer little mitigation of these unwanted harmonics. Recently, resonant controllers have emerged as an alternative to dq-frame controllers for regulation of grid connected converters for distributed resources. Although these control systems behave somewhat similar to dq-frame controllers under balanced operating conditions, their behaviour under unbalanced operation is superior. Currently, there are no linearized state space models of resonant controlled VSC systems. This work will develop a linearized small signal state space model of a VSC system, where resonant current controllers are used for regulation of the grid currents. It will also investigate the stability of resonant controlled VSC based systems using eigenvalue analysis for HVDC applications.

Keywords: VSC
HVDC
Resonant Control
Small Signal Modeling
Advisor: Lehn, Peter W.