VictorJuiz/thesis huggingface dataset:
Multicohort Management and LiDAR: New Forest Management Tools for Northeastern Ontario Boreal Mixedwood Bird Communities
Keywords: Multicohort Management
bird
Boreal
Forestry
forest structure
vertical stratification
LiDAR
multiscale analysis

While traditional management of the boreal forests results in even-aged forests with low landscape scale variability, recent work has suggested that much of the eastern boreal forest of North America is subject to long natural fire return-intervals. This has led to the development of new management strategies to maintain a mosaic of even and multi-aged stands. In this context I investigated the relationships between diameter-distributions, stand age, forest structure and bird communities. Results showed weak associations of the bird community with cohort classes, but that diameter-distributions can work to succinctly describe some of the variation in stand structure and bird communities. I also explored the utility of LiDAR to measure important structural features for bird communities. Results showed that LiDAR can outperform traditional measures of stand structure at explaining bird communities at differing scales.
A Novel Role for Tid1 in HIF2α Regulation
Keywords: Tid1
HIF
renal cell carcinoma
hypoxia inducible factor
VHL
von Hippel Lindau

Activity of the hypoxia inducible HIF-alpha transcription factors drive the hypoxic response, resulting in enhancement of angiogenesis, tumour growth, invasion and metastasis. Seeking to uncover a role for Tid1 in control of HIF2-alpha, we used lentiviral shRNA to knock-down Tid1 in 786-0 RCC cells with and without pVHL. In 786-0 cells stably expressing pVHL30, Tid1 knock-down resulted in a dramatic reduction in HIF2-alpha levels relative to controls. Adenoviral-mediated overexpression of Tid1S rescued this decline in HIF2-alpha levels, while overexpression of Tid1L enhanced this decline. A protective role of Tid1S for HIF2-alpha was reproduced in a HEK293 cell model. Immunoprecipitations in HEK293 cells revealed a lack of direct binding between HIF2-alpha and Tid1 in vivo, while adenoviral-mediated overexpression of Tid1 in this model failed to alter in vitro binding between HIF2-alpha and pVHL30. We present a model in which Tid1 regulates HIF2-alpha stability through regulation of pVHL30 nuclear import.
Synthesis and Characterization of Citrate and Polymer Stabilized Lanthanide Trifluoride Nanoparticles
Keywords: nanoparticle
lanthanide
citrate
poly(acrylic acid)
MRI
contrast agent
NMR
diffusion
gadolinium

Citrate-coated gadolinium trifluoride (Cit-GdF3) and poly(acrylic acid)-coated nanoparticles (PAA-GdF3 NPs) were synthesized, the former reproduced from literature (though using more refined conditions), the latter through a new, two-step, ligand exchange method. Diamagnetic nanoparticle analogs (Cit-YF3 NPs) were prepared to investigate citrate interactions with the nanoparticle surface using NMR. Citrate was found to bind in numerous conformations, with a total of between 29 – 46 % bound at 0 ºC. Exchange studies revealed short residence lifetimes of one and twelve seconds respectively for bound and free forms of citrate (0 ºC), perhaps explaining the colloidal instability of these nanoparticles. PAA-GdF3 NPs were synthesized by first producing their Cit-GdF3 counterparts, and then exchanging citrate for PAA. The impetus behind this latter synthesis was the relative enhancement in stability and relaxivity attainable by these nanoparticles. The displacement of citrate by PAA was verified using diffusion NMR studies.
Biomimetic Aminoacylation: Optimization of Reaction Conditions
Keywords: Aminoacylation
Bioorganic
Lanthanum

Synthesizing proteins containing unnatural amino acids inserted at specific positions within the protein sequence has been a longstanding goal of biological chemists. This poses unique challenges, as aminoacyl tRNA synthetases, the enzymes responsible for protein synthesis, are highly specific. To overcome this, a lanthanum-catalyzed, biomimetic tRNA aminoacylation method has been developed(1). However, due to unproductive lanthanum coordination of ethyl phosphate, a reaction byproduct, a full equivalent of lanthanum must be added to each reaction. This may threaten the integrity of tRNA, as lanthanides are known to catalyze the hydrolysis of RNA (2, 3). Using uridine as a simplified tRNA mimic, magnesium, which is known to coordinate strongly with phosphate ions, has been utilized to optimize this reaction and increase the selectivity of lanthanum towards esterification. In the presence of magnesium, ester yield is substantially increased. In addition to this, optimal pH and buffer reaction conditions were determined.
Numerical Shape Optimization of Airfoils With Practical Aerodynamic Design Requirements
Keywords: computational aerodynamics
optimization
airfoil

Practical aerodynamic shape design problems must balance performance optimization over a range of on-design operating conditions with constraint satisfaction at off-design operating conditions. A multipoint optimization formulation can be used to represent on-design and off-design conditions with corresponding objective or constraint functions. Two methods are presented for obtaining optimal airfoil designs that satisfy all design objectives and constraints. The first method uses an unconstrained optimization algorithm where optimal design is achieved by minimizing a weighted sum of objective functions at each of the conditions. To address competing design objectives between on-design and off-design conditions, an automated procedure is used to weight off-design objective functions to limit their influence on the overall optimization. The second method uses the constrained optimization algorithm SNOPT, allowing aerodynamic constraints imposed at off-design conditions to be treated explicitly. Both methods are applied to the design of an airfoil for a hypothetical aircraft, which is formulated as an 18-point multipoint optimization.
Eye Movements as a Reflection of Binding in Older Adults
Keywords: Relational Memory
Eye Movement Monitoring

Theories of age-related memory decline debate whether the problem lies at the level of encoding or consciously accessing information at the level of retrieval. Deficits at encoding may be due to the inability to bind relations among objects. The present research implements eye movement monitoring into an associative memory task to explore age-related memory at encoding and retrieval. Eye movements of older and younger adults are compared. Three solitary items were presented during the study phase, and test responses were whether the spatial relation of these objects to one another was intact or manipulated when subsequently presented all together. Observed differences at the level of encoding in addition to the level of retrieval clarifies that there is not a deficit in consciously accessing encoded representations. Further, differences in relational binding at the level of encoding were observed, which supports the association deficit theory of memory and aging.
Analysis of the Low-bid Award System in Public Sector Construction Procurement
Keywords: Construction
Procurement
Low-Bid

Canadian construction participants have long recognized that accepting the lowest price bid does not guarantee maximum value. Achieving a value-based procurement approach is a challenge, particularly for the Canadian public sector clients who are limited in their ability to evaluate the competitive bids based solely on the low-bid award system. Bid and cost data from 218 projects from three major public sector construction clients in the Greater Toronto Area are evaluated. Compared to the other clients, the cost escalation is significantly higher for the client that does not have a standard prequalification policy. Increased contractor competition (high number of bids) and a large price gap between low bid and other bids are correlated to higher cost escalation for the non-prequalifying client. Also, the organizational culture of the non-prequalifying client is less results-oriented. The research demonstrates the importance of prequalifying for clients that award based solely on the low bid.
Insect Communities and Multicohort Stand Structure in Boreal Mixedwood Forests of Northeastern Ontario
Keywords: Multicohort Management
Carabidae
Boreal
Forestry
insects
vertical stratification
canopy
understory
Hymenoptera
Diptera
forest structure

Current forest management in boreal northeastern Ontario results in young, even-aged forests; however, fire history research has found old stands with multiple cohorts of trees are common, supporting the value of Multi-cohort Management. I investigated relationships between insect communities and stand live-tree diameter distribution, cohort class and structure. Results showed that variation in abundances of Carabidae, Diapriidae, Diptera and Hymenoptera were not strongly predicted by cohort class. The concept showed greater strength when parameters of live-tree diameter distributions were used. Forest structure, not age, was important for all communities, including heterogeneity of understory and/or overstory vegetation. Trap height was a strong predictor of aerial insect community structure, with insect abundance higher in the understory than in the canopy. In summary, a more diversified classification approach which includes important habitat features in addition to simple characterization of diameter distributions should be considered to better assess forest structural variation and management.
Hepatocyte Cytotoxicity Induced by Hydroperoxide (Oxidative Stress Model) or Dicarbonyls (Carbonylation Model): Prevention by Bioactive Nut Extracts or Catechins
Keywords: Nut Extracts, Catechins, Cytotoxicity, Oxidative Stress, Lipid Peroxidation, Protein Carbonylation

Carbonyl and oxidative stress augment the development of diabetic complications. We evaluated the cytoprotectiveness of walnut and hazelnut extracts and catechins for decreasing cytotoxicity, lipid peroxidation, reactive oxygen species (ROS) formation, and protein carbonylation in cell death models of carbonyl and oxidative stress. Polar extracts (methanol or water) showed better cytoprotection than the non-polar (ethyl acetate) nut extracts against hydroperoxide-induced hepatocyte cell death and oxidative stress markers. Catechin flavonoids found in plants, including walnuts and hazelnuts, prevented serum albumin carbonylation in a carbonyl stress model (using glyoxal or methylglyoxal). Hepatocyte protein carbonylation and cell death were prevented and UV spectra data suggested a catechin:methylglyoxal adduct was formed. We conclude that (a) bioactive nut constituents in polar extracts were more protective than non-polar extracts against oxidative stress, and (b) catechins were effective under physiological temperature and pH, at preventing dicarbonyl induced cytotoxicity likely by trapping dicarbonyls or reversing early stage carbonylation.
Optimization of Nitrogen Acquisition, and Metabolism, by Potassium in Rice, and Barley
Keywords: Plant nutrition
Nitrogen
Potassium
Ion channel
Influx
Efflux
Rice
Barley
Futile cycling

We present the first characterization of K+ optimization of N uptake and metabolism in an NH4+-tolerant species, tropical lowland rice (cv. IR-72). 13N radiotracing showed that increased K+ supply reduces futile NH4+ cycling at the plasma membrane, diminishing the excessive rates of both unidirectional influx and efflux. Pharmacological testing showed that low-affinity NH4+ influx may be mediated by both K+ and non-selective cation channels. Suppression of NH4+ influx by K+ occurred within minutes of increasing K+ supply. Increased K+ reduced free [NH4+] in roots and shoots by 50-75%. Plant biomass was maximized on 10 mM NH4+ and 5 mM K+, with growth 160% higher than 10 mM NO3--grown plants, and 220% higher than plants grown at 10 mM NH4+ and 0.1 mM K+. Unlike in NH4+-sensitive barley, growth optimization was not attributed to a reduced energy cost of futile NH4+ cycling at the plasma membrane. Activities of the key enzymes glutamine synthetase (GS) and phosphoenolpyruvate carboxylase (PEPC) were strongly stimulated by elevated K+, mirroring plant growth and protein content. Improved plant performance through optimization of K+ and NH4+ is likely to be of substantial agronomic significance in the world’s foremost crop species.
Establishment of High Seas Marine Protected Areas: Towards an Implementing Agreement?
Keywords: marine protected areas
marine biodiversity
international law

Although international law requires States to protect the marine environment and conserve marine living resources, human activities are still threatening marine species and its survival. In view of limited scientific knowledge of marine ecosystems, fragility of ecosystems and insufficient mechanisms of protection, marine biodiversity in areas beyond national jurisdiction is at risk. Increasing attention has been given to the need to conserve this important and vulnerable biodiversity. The international community has begun to recognize the importance of marine protected areas (MPAs) as key tool to ensure sustainable use and preservation of biodiversity. However, the adequacy of the current legal framework related to the conservation of marine biodiversity through the establishing of high seas MPAs raises debates. Disagreements about the existence of inadequacies and need for an implementing agreement remain. My study seeks to determine whether the international legal framework is adequate for the establishment of MPAs or whether further measures are required.
Structural MR Imaging of Irritable Bowel Syndrome
Keywords: IBS
MRI
Pain
Cortex

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder. Cortical thinning of the anterior mid-cingulate cortex (aMCC) and insula has been previously reported in IBS (Davis et al., 2008). The aim of the present study was to examine cortical and subcortical structural gray matter integrity in IBS with particular attention to individual disease symptoms and personality characteristics such as pain catastrophizing. Eleven IBS patients and 16 age-matched healthy subjects (female, right-handed) underwent structural MRI. Voxel Based Morphometry and Cortical Thickness Analysis revealed that the IBS group had increased gray matter density in the hypothalamus, cortical thinning in the aMCC, strong (r = -66; p=0.015), a negative correlation between dorsolateral prefrontal cortex and pain catastrophizing and anterior insula thickness was positively correlated to pain duration (r = 0.77, p=0.003) when controlling for age. These abnormalities may contribute to chronic pain in IBS.
Access to Primary Health Care: Does Neighbourhood of Residence Matter?
Keywords: geographic information systems
GIS
primary health care
access to health care
neighbourhood
neighbourhoods and health
geography
health geography

Access to primary health care is an important determinant of health. Within current research there has been limited examination of neighbourhood level variations in access to care, despite knowledge that local contexts shape health. The objective of this research is to examine neighbourhood-level access to primary health care in the city of Mississauga, Ontario. Street address locations of primary care physicians were obtained from the College of Physicians and Surgeons of Ontario (CPSO) website and analyzed using geographic information systems (GIS). A 'Three Step Floating Catchment Area' (3SFCA) method was derived and used to measure multiple dimensions of access for the population as a whole, for specific linguistic groups and for recent immigrants. This research identifies significant neighbourhood-level variations in access to care for each dimension of access and population subgroup studied. The research findings contribute to a more nuanced understanding of neighbourhood-level variability in access to health care.
Corporate Managers and the Wide Discretion for their Fiduciary Duties: Problematic or not?
Keywords: Corporate Law
Fiduciary Duties
Managerial Discretion

As a result of the Supreme Court’s broad definition for ‘best interests of the corporation’ in recent decisions, the author examines to whom managers ought to owe their fiduciary duties normatively and what role managerial discretion has in this debate. The author argues that the lack of clarity offered by the judiciary, in this area of corporate law, has led to the adoption of a wide discretion being afforded to managers. An examination of several rationales fails to justify this continued adoption of a broad discretion. The author argues that granting managers with wide discretionary powers is problematic because the interests of constituencies will not be adequately protected. At the very least, statutory reform is necessary to protect the most vulnerable stakeholders. The author recommends that the law be amended to require that managers, in performing their fiduciary duties, regard the interests of employees and shareholders.
Income Tax Treatment of Credit Swaps in Canada: Enhancing Tax Neutrality
Keywords: derivatives
tax policy
credit swaps
taxation

This study examines the issue of tax neutrality of the income tax treatment of credit swaps in Canada in domestic context. It analyzes the applicable tax regime consisting of rules on tax characterization, timing and tax rates through the lenses of symmetry, consistency and certainty approaches. The study argues that the Canadian tax policy focuses on achieving symmetry in income tax treatment, rather than consistency. This is because introducing consistency would contradict the fundamental principles of the Canadian law. The study finds that the current tax regime is only partially neutral because symmetry has not been achieved in respect to credit swaps entered between non-financial organizations. To enhance symmetry, the study proposes to adopt a mandatory mark-to-market basis of taxation of credit swaps for the non-financial organizations. Further, to make income tax treatment more certain, the study proposes that the CRA should issue a non-binding guidance on credit swaps.
Disingenuous or Novel? An Examination of Apology Legislation in Canada
Keywords: Apology
Legislation
Health
Law

This Thesis provides an analysis of Apology Legislation in Canada, more specifically focusing on its influence on Canadian Courts & Contracts of Insurance. Apology legislation, as an amendment to the Evidence Act of a province or a stand-alone piece of legislation, was created to restrict the admissibility of acts or words of remorse or benevolence given by one person to another. Apology Legislation in Canada is said to be a positive measure on the road to making the justice system more accessible, affordable and effective. This piece will explore the framework of Apology Legislation in several common law jurisdictions, leading to an examination of the socio-economic and legal benefits it is purported to confer. This Thesis will also consider legal and policy changes that could help to alleviate the burden on the judicial system while contributing to the creation of a safer and more sustainable health care system in Canada.
Electrodeposition of Tantalum and Niobium Using Ionic Liquid
Keywords: electrodeposition
ionic liquids

Ionic liquids are molten salts with melting points below 100 °C and they consist entirely of cations and anions. The development of ionic liquids, especially air and water stable types, has attracted extensive attention since they have outstanding physical properties. Part I of the study focused on the pre-electrolysis process performed to remove impurities from the ionic liquid, 1-butyl-1-methyl-pyrrolidinium bis(tri-fluoromethylsulfonyl)imide, ([BMP]Tf2N). Part II investigated the electroreduction of TaF5 and NbF5 from room temperature ionic liquid at 100 °C at a wide range of potentials and different time durations for the purpose of determining the optimal conditions for the electrodeposition of tantalum. The study was carried out using potentiostatic polarization for the pre-electrolysis treatments and electrodeposition and cyclic voltammetry to study the behaviour of the liquid at various stages. Potentiostatic depositions were complemented by scanning electron microscopy (SEM)/energy-dispersive x-ray analysis (EDX), x-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD) for characterization of the electrodeposits.
Promoting Action on Research Implementation in Health Services (PARiHS) Framework: Application to the Fracture Fighters Program
Keywords: knowledge translation
osteoporosis
PARiHS framework
leadership
facilitation
organizational climate

The purpose of this thesis is to apply the Promoting Action on Research Implementation in Health Services (PARiHS) framework to a provincial osteoporosis management program to describe unit level factors that may have influenced implementation among participating inpatient rehabilitation units. A toolbox of measures was proposed to operationalize the frameworks elements of evidence, context and facilitation. A cross-sectional survey was completed with clinicians responsible for championing the program and their managers. Results demonstrated that leadership behaviours, organizational climate traits and champion behaviours varied among practice environments indicating that attention to unit level factors outlined by the PARiHS framework could increase the uptake of research evidence in practice. The proposed toolbox could be utilized as a diagnostic and prescriptive tool to identify potential implementation barriers, and guide the selection of appropriate tools/strategies to overcome them. Furthermore, it will enable future studies to provide further empirical support for the PARiHS framework
The in vivo Oxyhaemoglobin Dissociation Curve at Sea Level and High Altitude
Keywords: Oxyhaemoglobin Dissociation Curve
High Altitude
Oxygen Transport
Acclimatization

Some animals have adapted to hypoxia by increasing their haemoglobin affinity for oxygen, but in vitro studies have not shown any change of haemoglobin affinity for oxygen in human high altitude natives or lowlanders acutely acclimatized to high altitude. We conducted the first in vivo study of the oxyhaemoglobin dissociation curve by progressively reducing arterial PO2 while maintaining normocapnia in lowlanders at sea level, lowlanders sojourning at 3600m for two weeks and native Andeans at the same altitude. We found that the in vivo PO2 at which haemoglobin is half-saturated (P50) is higher in lowlanders at sea level (32 mmHg) than that measured in vitro (27 mmHg) and that lowlanders and highlanders do significantly increase the in vivo affinity of their haemoglobin for oxygen with exposure to high altitude. These results indicate the value of an in vivo approach for studying the oxyhaemoglobin dissociation curve.
Factors Affecting the Implementation of Complex and Evolving Techniques: A Multiple Case Study of Intensity-modulated Radiation Therapy (IMRT) in Ontario.
Keywords: Implementation
technology
barriers
facilitators
IMRT
radiation
health policy
decision making
cancer centres
case study
Ontario
knowledge translation
evidence
guidance

Background: Intensity Modulated Radiation Therapy (IMRT) is a method of delivering high-dose radiation to tumours while sparing surrounding healthy tissues. Despite its wide availability IMRT utilization varies across Ontario. The study’s objective was to examine key steps in the implementation process and identify factors that facilitate or impede IMRT implementation. Research Methods: An embedded multiple case study design, utilizing document analysis and key-informant interviews, was employed. Four cancer centres were selected and key-informant interviews were conducted with radiation oncologists, physicists, radiation therapists, and administrators. Results: Eighteen of 21 invited key-informants participated (86% participation rate) providing a range of insights on the factors influencing IMRT implementation. Overall, three cases made progress in the implementation of IMRT, while one case had limited implementation over the same time period. Conclusion: These findings help explain the observed variation in IMRT implementation across Ontario, which is multifaceted and reflects ongoing processes of change and reinvention.