VictorJuiz/thesis huggingface dataset:
Surface and Photochemistry of Oxidant Precursors on Atmospherically Relevant Aqueous Interfaces
Keywords: atmospheric chemistry
ice
photochemistry
snow
surface chemistry

Snow/ice surfaces represent important environmental interfaces that influence atmospheric composition and chemistry. It remains challenging to reconcile experimental and field studies, because the molecular-level processes that occur at the air-aqueous interface are not well-characterized. To improve our understanding of these interactions, laboratory techniques were used to interrogate the behaviour of impurities at the air-aqueous interface. A complementary field study was conducted to look for evidence of snow-mediated chemistry. A novel flow reactor systemâ featuring a Drilled Ice Flow Tube with varying degrees of crystallinityâ was built to directly observe the effect of ice microstructure on trace gas uptake. The uptake and recovery of hydrogen peroxide in monocrystalline and polycrystalline flow tubes are compared to discern between surface adsorption and diffusion into grain boundaries. Results from this study offers mechanistic insight into the physical uptake of trace gases to ice surfaces. Glancing-angle Raman spectroscopy was used to investigate nitrate distribution at the air-aqueous interface in the presence of halide ions. Co-occurring ions may alter the surface propensity of nitrate and affect its access for atmospheric chemistry. Results suggest that bromide enhances, and chloride has little effect on the surface propensity of nitrate. These results highlight the importance of the chemical environment on potential reactivity at the air-aqueous interface. In a field study, the chemical role of the snowpack was inferred from vertical concentration gradients of reactive nitrogen oxides and ozone measured over snowpacks with distinct compositions. The results from the campaign show that the snowpack is coupled to the atmosphere through complex air-ice chemical interactions and is likely influenced by co-occurring impurities, such as crustal particulates and organics. Overall, this dissertation aims to elucidate fundamental processes that inform how we conceptualize snow/ice chemistry, and identify important mechanisms that may be occurring in a real environment.
Photoprotective Isoprenoids as Indicators for Stress Responses in Forest Trees
Keywords: drought
intraspecific variation
non-photochemical quenching
photoprotection
photosynthesis
remote-sensing

For long-lived forest tree species, intraspecific variation among populations in their response to environmental conditions can reveal their ability to cope with and adapt to climate change. Plants constantly adjust the pigment composition of the photosynthetic apparatus to environmental conditions. Under abiotic stress conditions (e.g. drought), plants induce isoprenoid-mediated photoprotective mechanisms such as non-photochemical quenching (NPQ) and increased biosynthesis of antioxidants to minimize photooxidative stress. This thesis investigated the intraspecific variation in the isoprenoid metabolism in Douglas-fir (Pseudotsuga menziesii) comparing Douglas-fir provenances, which represent populations from locations with contrasting environmental conditions. Furthermore, the influence of foliar photosynthetic pigments on leaf optical properties was studied using senescing sugar maple (Acer saccharum) leaves. First, I established a simple and cost-effective protocol for the rapid analysis of isoprenoids using high-performance liquid chromatography (HPLC) (Chapter 2). Three experiments were conducted to evaluate 1) the adjustments of the isoprenoid metabolism when photosynthesis is limited in response to environmental conditions (Chapter 3 and 4); 2) provenance-specific adjustments of photoprotective isoprenoids in response to drought (Chapter 3 and 4); and 3) the influence of senescence-associated changes in isoprenoid levels on leaf optical properties in sugar maple (Chapter 5). In chapter 3, photosynthesis and photosynthetic pigments in seedlings of two Douglas-fir provenances were compared under controlled drought conditions. In chapter 4, intraspecific variation in photosynthesis and photosynthetic pigments in response to changing environmental conditions were studied in mature trees of four provenances over the course of two years. Both experiments revealed that the more drought-tolerant interior provenances exhibit enhanced carotenoid-chlorophyll ratios, and larger pools of xanthophyll cycle pigments and Î˛-carotene compared to coastal provenances from mesic habitats. This provenance-specific variation demonstrated the importance of the isoprenoid metabolism for the adaptation of provenances to drought. In chapter 5, the leaf optical properties of senescing sugar maple leaves were studied. The degradation of photosynthetic pigments as indicator for the progress of senescence was reflected by spectral reflectance measurements and digital image analysis. Isoprenoid metabolism may thus be a potential trait for selection of provenances for future forest management and indicator for remote-sensing of the plant physiological status.
Contrast and Complexity in Chinese Tonal Systems
Keywords: chinese
complexity
features
phonology
tone

Lexical tone has been investigated from a diverse variety of perspectives, with significant disagreement as to whether a feature-based analysis can account for the synchronic and diachronic patterning of tonal systems. This thesis investigates the tonal systems of 13 Chinese languages from the Yue and Mandarin groups, and presents a feature-based model which accounts for their respective inventories and patterns of phonological alternations, and traces their respective diachronic trajectories back to the feature specification of a reconstructed Middle Chinese tonal inventory. The analysis here employs hierarchically arranged contrastive features. Whereas analyses postulating a universal set of phonetic features tend to incur a number of descriptive and theoretical problems when tasked with the description of tonal systems, utilizing language-specific features grounded in tonal alternations and phonetics sheds significant light on synchronic and diachronic patterning. The reconstruction of a common Middle Chinese proto-language enables the description of a precise phylogenetic tree as well as the postulation of a number of contrastive reanalyses. It is found that both reanalysis and the specific phonetic content of tonal inventories are accounted for by postulating a principle of complexity minimization: the cognitive apparatus chooses representations which minimize the algorithmic entropy or Kolmogorov complexity of phonologies and maximize the reuse of structure. At each point in the diachronic trajectory of a language, speakers choose the phonological representation with the lowest total complexity. Phonetic naturalness can also be formalized as the minimization of complexity, and a general tendency towards an inverse relationship between the naturalness of tonal inventories and the amount of activity in a given language is described. The cognitive preference for the minimization of complexity represents a parsimonious solution to the problem of induction which avoids the stipulation of hard-coded universals pre-specified in the cognitive apparatus.
X-ray Computed Tomography Assessment of Air Void Distribution in Concrete
Keywords: air void system
cement-based material
image processing
X-ray CT

Air void size and spatial distribution have long been regarded as critical parameters in the frost resistance of concrete. In cement-based materials, entrained air void systems play an important role in performance as related to durability, permeability, and heat transfer. Many efforts have been made to measure air void parameters in a more efficient and reliable manner in the past several decades. Standardized measurement techniques based on optical microscopy and stereology on flat cut and polished surfaces are widely used in research as well as in quality assurance and quality control applications. Other more automated methods using image processing have also been utilized, but still starting from flat cut and polished surfaces. The emergence of X-ray computed tomography (CT) techniques provides the capability of capturing the inner microstructure of materials at the micrometer and nanometer scale. X-ray CTâ s less demanding sample preparation and capability to measure 3D distributions of air voids directly provide ample prospects for its wider use in air void characterization in cement-based materials. However, due to the huge number of air voids that can exist within a limited volume, errors can easily arise in the absence of a formalized data processing procedure. In this study, air void parameters in selected types of cement-based materials (lightweight concrete, structural concrete elements, pavements, and laboratory mortars) have been measured using micro X-ray CT. The focus of this study is to propose a unified procedure for processing the data and to provide solutions to deal with common problems that arise when measuring air void parameters: primarily the reliable segmentation of objects of interest, uncertainty estimation of measured parameters, and the comparison of competing segmentation parameters.
The Perfect Storm: Institutional and Organizational Antecedents of Title Fraud in Ontario
Keywords: Fraud
Institutionalism
Organizations
Professions

This dissertation contributes to organizational analyses of crime through the study of real estate title fraud. Through interviews with key constituents in the field of real estate conveyancing and lending, and through an analysis of documents produced by these constituents, this study elucidates both the antecedent institutional and organizational conditions giving rise to new opportunities for title fraud and the legal and governmental responses to this crime. Structured through three discrete papers, the data highlight the role of institutional change in the creation of new fraud risks and the ways in which these risks are conceptualized and mitigated. The first paper explores the conflict over professional jurisdiction between the Ontario real estate bar and title insurance companies. It elucidates the institutional shifts in the field of conveyancing and lending that open the legal profession to competition, and it explores the rhetorical strategies used by the real estate bar to adapt to the diffusion of prevailing practices that threaten their legitimacy. The second paper builds from and advances the explication of these field-level changes, demonstrating how institutional changes have eroded organizational guardianship by establishing anonymous systems that create new opportunities for fraud incubated in routine patterns of conveyancing activity. The third paper situates the governmentâ s response to fraud within the context of these field-level shifts. The violation of sacrosanct institutions of private property and homeownership undermines cultural ideologies of the home and imbues the acquisition of property with uncertainty. The significant public and political attention generated by title fraud compelled immediate and atypical state intervention in the rectification of harm and the restoration of title to victims. Altogether, these three papers elucidate the role of the institutional environment in creating opportunities for crime through the incubation of fraud risks, and for compelling atypical state responses to forms of identity crime like title fraud.
Towards Competency-Based Assessments in General Surgery
Keywords: Competency-Based Assessment
Competency-Based Education
General Surgery
Performance Standards
Residents
Surgical Education

Introduction: The training of surgical residents has seen a tremendous shift in education and assessment paradigms over the last decade. The traditional time-based framework, which has essentially remained unchanged since its conception over a hundred years ago is being replaced, albeit slowly, by a new competency-based framework. Despite the need for such change and this almost inevitable transition, there is currently a lack of evidence to support and operationalize many education and assessment facets within this new framework. The main goal of this thesis is to collect evidence that helps bridge many of the knowledge gaps currently present in order to support the transition towards competency-based training in General Surgery. Methods: All data were prospectively collected and analyzed using descriptive and inferential statistics (both parametric and non-parametric). Research designs contained within the thesis include: a systematic review in accordance with current guidelines, a census survey, a consensus Delphi methodology and two cross-sectional observation studies. Traditional and contemporary frameworks of validity (and reliability) were adhered to throughout. Results: Five research studies were completed. A systematic review, which documented the methods by which technical competence is currently assessed in surgical trainees, that there is a lack of performance standards in surgical education and how best to differentiate between the terms competency and proficiency. An international education directorateâ s census survey, which acknowledged current and ideal assessment practices across various surgical jurisdictions and barriers to the implementation of competency-based assessments at all three phases of surgical training (selection, in-training and certification). A Delphi methodology, which created a new training and assessment model for varying levels of trainees in General Surgery, rooted in previously set guidelines. A cross-sectional study, which demonstrated that staff surgeons are reliable assessors of trainee technical and non-technical performance. Finally, a multi-center cross-sectional study, which set performance standards for technical and non-technical performance, demonstrated a discrepancy in some traineesâ ability to meet both standards concurrently and examined factors that can predict standard (competence) acquisition. Conclusions: The findings contained within this thesis contribute evidence to the operationalization of competency-based assessments in General Surgery.
An Exploration of BAFF, APRIL and their Receptors in the context of IgA Nephropathy and Plasma Cell Migration
Keywords: antibody secreting cells
anti-commensal antibodies
BAFF-tg mice
IgA Nephropathy
migration

Introduction: IgA Nephropathy is the most common nephritis worldwide. Few treatments are available and disease etiology remains unclear, although APRIL has been implicated. BAFF-transgenic (-tg) mice require a microbiome to initiate disease, and these mice exhibit intestinal hyperplasia of Plasma Cells (PC) and hyperproduce IgA. I hypothesize that B cells that encounter antigens in the gut can egress from the gut and may potentially influence disease pathology. Methods: ELISAs were used to measure BAFF/APRIL and commensal-specific antibodies in the periphery of BAFF-tg mice and human IgAN patients. PC migratory ability was tested via: (1) dual infection of Rotavirus (RV) and Influenza PR8 (flu), or experimental autoimmune encephalomyelitis (EAE); (2) RV infection and parabiosis; and (3) intestinal photoconversion in Kaede mice. RV-specific PC were measured in (1) and (2) in distal tissues via ELISPOT. BAFF-tg immune response to flu was measured through survival, viral titres, and inducible bronchus associated lymphoid tissue (iBALT) formation. Results: Anti-commensal antibodies were found in BAFF-tg serum and kidneys as well as in human serum both in healthy controls and IgAN patients. RV-specific IgA+ PC can migrate from the intestine to distal tissues, including the lung during flu and homeostatically, and to the CNS after the peak of EAE disease in both BAFF-tg and WT mice. RV-specific IgA+ PC can also migrate from one parabiont to another after 30 days. In Kaede mice, photoconverted cells migrate to the lungs during flu and homeostatically. BAFF-tg mice had an enhanced immune response to flu infection, generating iBALT 4 days earlier than WT mice. However, this did not exacerbate renal disease or alter the viral load. Conclusions: In WT mice, B cells primed in the intestine can migrate to distal tissues during inflammation and to the lungs homeostatically. However, only BAFF-tg mice had anti-commensal antibodies in their serum. While BAFF-tg mice generated an enhanced immune response to flu, this did not exacerbate renal pathology or change the viral load. Further studies are required to ascertain the implication of gut immunity entering the periphery, the function of these migrating PC and the impact this may have in a chronic disease setting.
Developing Collective Musical Personae: A Toronto-Based Study of the Performance Practices of Stable Jazz Groups
Keywords: Canada
jazz
performance
Toronto

Using the analytical lenses and methodologies of jazz studies, ethnomusicology, and cultural studies, this dissertation considers a recent trend among many younger Toronto jazz musicians. While the national reputation of Toronto’s jazz scene has long been defined by a “swing-to-bop” mainstream sound, since the late 1990s the scene’s economic foundations that supported this mainstream—including a multitude of well-paying venues and a thriving studio recording industry—have mostly collapsed. Without these economic incentives, many younger Toronto musicians have moved away from the bop-oriented mainstream’s usual focus on individual improvising prowess on repertoire with narrow stylistic parameters. Instead, many younger Toronto musicians have been performing much more highly distinctive original compositions. I argue that this idiosyncratic repertoire, and especially the approaches to improvisation employed when performing it, could only develop through long-term commitment to ensembles with fixed membership. Among the groups that participated in my study, stability allowed for the musicians to foster a multi-layered, collective approach to interaction – not only in how they performed with each other, but in how the composers and players interacted with musical traditions themselves, including jazz. On the one hand, I show how this trend to the long-term group has been influenced by a history of stable group activity in jazz that has been, with only a few exceptions, overlooked in jazz scholarship. On the other hand, I point out how the highly developed sense of group identity in rock bands may also have been influential for these young Toronto musicians. During my fieldwork, all of these groups performed within a small circuit of venues in and around Toronto. These venues—and the musicians, and the audiences who interacted socially and musically within it—formed an overlapping part within the jazz scene – what I call a subscene. Using four groups as primary examples, I explore how these bands formed and then promoted themselves in this subscene. This sets up my in-depth analysis of how these musicians composed and improvised in ways that were reliant on their consistent interactions over an extended period of time – practices that helped to solidify these groups' collective musical personae.
Racial Disparities in Police Stops in Kingston, Ontario: Democratic Racism and Canadian Racial Profiling in Theoretical Perspective
Keywords: Critical Discourse Analysis
Police Unions
Race and the Criminal Justice System
Racial Profiling
Racism and Policing
Stop and Search

This study takes a quantitative and qualitative approach to examine police stops in an Ontario city. The author finds that Black residents were over stopped by police, and the over stopping may not be fully explained by the police-reported reasons and dispositions of the stops. In other words, the author suggests that police stops have less to do with crime control models of criminal justice, and more to do with surveiling marginalized populations. The author uses critical discourse analysis to examine news coverage of the racial profiling controversy in Ontario, including news reports on the study. The author argues that public discourse (both liberal 'anti-profiling' advocates and conservative supporters of police) contributes to the continued targeting of certain groups, by constructing an ideal victim of racial profiling (middle class, respectable), thus excluding all other subjects from legitimately seeking freedom from being hassled by police and having freedom of movement enjoyed by the nonprofiled population. The study also uncovers the influential role of police unions in Ontario in manipulating political discourse on race and policing.
Predictors of Bullying Involvement in Young Adolescents: The Role of Internalized and Externalized Anger, Emotional Intelligence and Narcissism
Keywords: anger
bullying
bully-targets
direct bullying
emotional intelligence
indirect bullying

This study was intended to identify unique social-emotional traits of participants involved in bullying. The participants were students in Grades 7 and 8 from five schools in Midwestern Ontario (N = 412). Measures of bullying, anger, emotional intelligence, and narcissism were administered to operationalize components of a hybrid socio-emotional model of school based bullying. Five distinct subgroups of bullies and targets were identified. These were: (1) Bullies, participants who were aggressors with a power advantage who repeatedly hurt, humiliated, or dominated peers; (2) Directly Aggressive Bullies, participants who were aggressors whose identity was known to the Target; (3) Indirectly Aggressive Bullies, participants who were aggressors whose identity was concealed from the Target; (4) Targets, participants who were recipients of repeated peer aggression for which they had limited ability to prevent; and (5) Bully-Targets, participants who met the study criteria for involvement both as Bullies and Targets. All other participants in the research were assigned to the Non-Involved Group. Boys in each of the grades and boys and girls in Grade 8 were more likely to be classified as Directly Aggressive Bullies and as Bully-Targets than Non-Involved students. Directly Aggressive Bullies were more likely to report high levels of externalized anger and to have difficulty managing their emotions. Classification as an Indirectly Aggressive Bully was predicted by higher levels of internalized anger. Lower levels of externalized anger and higher levels of internalized anger and extent of anger predicted classification as a Target. Bully-Targets also reported higher levels of externalized anger, internalized anger, and lower levels of narcissism than the Non-Involved group. These results suggest that anger management should be the central focus of interventions designed to reduce bullying. This focus is especially important for Bully-Targets who have high levels of both internalized and externalized anger. Other identified groups of students who are either directly aggressive bullies, indirectly aggressive bullies or targets may need specialized interventions to overcome their triggers for anger. The overall results of the study support an individualized approach, rather than a generalized approach, to intervene successfully in schools and the community to reduce bullying behaviour.