VictorJuiz/thesis huggingface dataset:
Comparing Remote Sounding Measurements of a Variable Stratosphere

The measurement of trace gases through remote sounding techniques has led to a better understanding of the processes controlling the structure and variability of the stratosphere. Differences between measurements over space and time are due to atmospheric variability and instrument errors: thus, comparison of measurements can be used to test our knowledge of both. Comparisons of measurements over long time periods are used to identify trends. Balloon-borne infrared emission radiometer instruments have been used to make measurements of midlatitude stratospheric HNO3 spanning a period of twelve years. The timing of the measurements is notable, since they occur before and well after the eruption of Mt. Pinatubo, which significantly perturbed HNO3 levels, complicating prior trend analyses. No significant differences are found between the HNO3 retrievals, although large measurement uncertainties preclude any conclusion concerning trends. Comparisons of measurements that are closely spaced in space and time are useful for satellite validation, where one aims to reduce the effect of atmospheric variability on the estimation of systematic and random errors. A novel technique for the estimation of systematic error, which differentiates between additive and multiplicative bias, is introduced. In a comparison of measurements by the ACE-FTS and Aura MLS instruments, significant multiplicative biases are identified and described. In order to validate the reported random errors (RREs) of measurements, satellite validation studies often focus on measurements in the tropical stratosphere, where variability is weak. The scatter in tropical measurements can then be used as an upper limit on instrument precision. In an analysis of tropical measurements by the ACE-FTS, scatter is found to be roughly consistent with the RREs for H2O and CO. The scatter in measurements of O3, HNO3, and N2O, while larger than the reported random errors, is roughly consistent with the variability simulated in the Canadian Middle Atmosphere Model. This work implies that the random error of the ACE-FTS measurements is smaller than the weak natural variability of the tropical stratosphere.

Keywords: Stratosphere
Remote sounding
Satellite validation
Atmospheric composition
Advisor: Strong, Kimberly
Manufacturing Conflict? An Ethnographic Study of the News Community in Abidjan, Côte d’Ivoire

This ethnographic study explores the experiences of Ivorian journalists in the context of the 2002-2009 crisis in Abidjan, the economic capital city of Côte d’Ivoire. I present material on the political affiliations of newspapers, the structure of the news industry, the attitudes of journalists, and certain aspects regarding the reception and dissemination of media texts in the streets of Abidjan. My interests lie in analysing the origins and the impacts of the accusations to which journalists of the written press are being subjected concerning their role in the Ivorian conflict. I explore how the crisis has been constructed and construed by and through media agents. I focus on the reflexive moments of journalists and on what their metadiscourses reveal about the context of news production in Côte d’Ivoire. Data was collected through participant-observation and interviews over 18 months of fieldwork in 2003, 2004-2005 and 2006 mainly in three newsrooms in Abidjan. This dissertation questions the emphasis placed upon the role of media in African conflicts, which I term the Rwandan paradigm. The Rwandan paradigm is the reductionist notion that mass media indoctrination plays a decisive role in mobilizing African audiences to commit acts of communal violence. Ultimately, I suggest two avenues to broaden our understanding of the intersection between communication and conflict: 1) a recognition of the complex agency of media producers and their audience; 2) an exploration of alternative media and public spaces.

Keywords: media anthropology
Côte d'Ivoire
conflict
journalism
agency
Rwandan Paradigm
Advisor: Kalmar, Ivan Davidson
Orchestration of the DNA Damage Checkpoint Response through the Regulation of the Protein Kinase Rad53

In order to maintain genome stability, DNA damage needs to be detected and repaired in a timely fashion. To cope with damaged DNA, cells have evolved mechanisms termed "checkpoints", where, upon damage, cells initiate a signal transduction cascade that results in the slowing or halting of the cell cycle, allowing efficient DNA repair. Defects in the DNA damage checkpoint result in an overall increase in genomic instability and are thought to fuel cancer progression. To facilitate our understanding of how DNA damage leads to cancer progression, it is crucial to fully comprehend how these signal transduction mechanisms function. In this work, we have characterized in great detail the mechanisms of regulation of Rad53 (a central regulator of the DNA damage response in Saccharomyces cerevisiae) at the genetic, biochemical and structural level. Firstly, we describe a complex biochemical two-step mode of activation of Rad53 by protein-protein interaction and multi-step phosphorylation. We also shed light onto the mechanisms by which Rad53 is turned off to allow the cell cycle to resume, a process termed DNA damage recovery and adaptation. We found that during adaptation, the polo-like kinase Cdc5 is required to attenuate Rad53 catalytic activity. Finally, the study of Rad53 at the molecular and atomic level revealed that in addition to being regulated through a complex network of protein-protein interactions, Rad53 autophosphorylation is orchestrated by a mechanism of dimerization, activation segment phosphorylation via A-loop exchange, as well as through an autoinhibition mechanism regulated by a specific alpha-helical region at the C-terminal extremity of its kinase domain. Such work is important in understanding the function of different proteins in DNA damage signaling. This knowledge will enhance our understanding of the progression of DNA damage related diseases such as cancer, and could eventually help in the long term the development of novel therapeutics as treatments against these conditions.

Keywords: Checkpoint
DNA damage
Rad53
saccharomyces cerevisiae
Advisor: Durocher, Daniel
Fibre Reinforcement for Shrinkage Crack Control in Prestressed, Precast Segmental Bridges

In prestressed precast segmental concrete bridges, conventional longitudinal reinforcement serves only as shrinkage crack controllers. The presence of this reinforcement, however, has restricted the ability to reduce the cross-section of the segments when high strength concrete is used because of the minimum dimensions required to accomodate the reinforcement. Research on fibre reinforced concrete (FRC) indicated that the addition of steel fibres to concrete significantly improved the tensile behaviour and the crack control characteristics of the concrete. This research investigates the feasibility of fibres to replace the conventional shrinkage reinforcement, allowing for the design of thinner and lighter structures with comparable or better crack control characteristics. Extensive work was conducted to investigate the effectiveness of hooked-end steel fibres to control cracks. Seven types of material tests were performed: uniaxial tension test, cylinder compression test, modulus of rupture test, splitting test, free and autogenous shrinkage test, and restrained shrinkage test. In addition, ten 890×890×70 mm concrete panels were tested under in-plane pure-shear loading using the Panel Element Tester. The parameters of study were the fibre volume content (0.5%, 1.0%, and 1.5%), the concrete compressive strength (50 and 80 MPa), and the fibre geometry and tensile strength. In addition to the experimental study, a model was developed to investigate the behaviour of a 1D restrained FRC member subjected to shrinkage. The experimental results indicated that the addition of fibres significantly improved the behaviour of the concrete, particularly the crack control characteristics, the post-peak compressive response, the post-cracking tensile response, the toughness, and the ductility of the concrete. The results also indicated that steel fibres were as effective as conventional reinforcement in controlling shrinkage cracking, provided that sufficient fibre volume content was added to the concrete. For example, in order to achieve a maximum crack width of 0.35 mm, a minimum fibre content of 0.9% and 1.1% should be provided for 50 MPa FRC containing high aspect ratio fibres and low aspect ratio fibres, respectively. In addition, the results indicated the importance of fibre content and fibre aspect ratio on the effectiveness of fibre reinforcement.

Keywords: fibre reinforced concrete
steel fibres
crack control
shrinkage
Advisor: Gauvreau, Douglas Paul
Vecchio, Frank J.
The Return of the Vanishing Formosan

Stories about aborigines in a settler society, especially stories about aboriginal maidens and settler men, tend to become national allegories. Initially, the aboriginal maiden is a figure for colonial landscapes and resources, while later, in her conversion in fact or fiction from aboriginal to settler, she helps build national identity. Yet after being romanced, the aboriginal maiden’s fate is to disappear from settler consciousness, because she is displaced by the national settler mother or because the settler loses interest in her, only to return in abjection to haunt the settler conscience. In her return as a prostitute, a commodified bride or a ghost, she disturbs the discourse of ‘national domestication’, the notion of nation as family. Though she returns in abjection, an Amazonian association tends to linger in the person of the aboriginal maiden, an association that suggests the kind of self-empowerment on which a healthy liberal society depends. In other words, the figure of the aboriginal maiden tends to be used in the construction, the contestation, and potentially the reconstruction of national identity in a settler society. While I discuss examples from settler societies around the world, particularly the story of Pocahontas, and try to contribute to ‘settler colonial discourse studies’, I focus on postwar Taiwan. This dissertation proposes the notions of the ‘settler society’ and the Habermasian public sphere as ‘frames’ for the study of Taiwanese literature. I show how the Formosan aboriginal maiden has been appropriated for the construction and critique of both Chinese and Taiwanese nationalisms. I argue that while nationalism is partly about social control and the advancement of particular interests, writers who have romanced the Formosan aborigine have been implicitly participating in a debate about national domestication, the telos of which is the democratic imagination of a good society, one in which the Formosan aborigines will feel in some sense ‘at home’, though perhaps not as members of the ‘national family’. Finally, under the rubric of ‘alternative aboriginal modernities’, I discuss stories that reread the romance of the Formosan aborigine by aboriginal writers who have entered the national debate.

Keywords: settler society
national allegory
Taiwanese literature
aboriginal domestication
Advisor: Liu, Johanna Chien-mei
The Role of Fas-mMediated Apoptosis in the Pathophysiology of Acute Traumatic Spinal Cord Injury

Spinal cord injury (SCI) is a debilitating condition accompanied by motor and sensory deficits and a reduced quality of life. Current treatment options are limited and are associated with variable efficacy and a risk of adverse effects. The pathophysiology of SCI is initiated by a primary mechanical insult to the spinal cord, followed by a complex series of deleterious events known as secondary injury. Secondary injury processes include free radical formation, glutamate excitotoxicity, inflammation and cell death. Apoptotic cell death in particular plays a key role in the secondary injury processes and exacerbates tissue degradation and loss of function. The role of Fas-mediated apoptosis in SCI pathophysiology is poorly defined in the literature to date. Correlative evidence suggests that this form of cell death is delayed and occurs in white matter adjacent to sites of primary damage. The cellular and temporal mechanisms of Fas-mediated apoptosis following experimental SCI were evaluated using a clinically relevant clip compression SCI model in the rat. Furthermore, therapeutic manipulation of Fas activation using a soluble form of the Fas receptor (sFasR) was carried out to establish the efficacy and clinical relevance of targeting this aspect of secondary injury. This work shows that Fas-mediated apoptosis is an important contributor to secondary SCI pathology. Oligodendrocytes are targeted by this form of cell death in a delayed fashion post-injury, providing an opportunity for therapeutic intervention. Intrathecal administration of sFasR following SCI reduced post-traumatic apoptosis, improved cell survival, enhanced tissue preservation and resulted in an improved motor recovery. Administration of sFasR was effectively delayed by up to 24 hours post-injury, however a shorter delay of 8 hours post-injury was most efficacious. A surprising result emerged from this work. Delayed intrathecal administration of IgG following SCI showed significant efficacy in both cellular and tissue level outcomes, as well as at the functional level. Fas-mediated apoptosis is an important aspect of secondary SCI pathophysiology and is an attractive therapeutic target. The beneficial outcomes of manipulating Fas activation using sFasR provide further evidence for this. Future work will refine this treatment strategy, bringing it into the SCI patient population.

Keywords: spinal cord injury
apoptosis
Fas receptor
neuroprotection
Advisor: Fehlings, Michael G.
American Sign Language and Early Literacy: Research as Praxis

This thesis presents an ethnographic action research study of Deaf and hearing parents and infants participating in a family American Sign Language (ASL) literacy program in Ontario. The thesis documents the context for parents and children’s learning of ASL in an environment where resources for supporting early ASL literacy have been scarce. At the time of the study, restrictions were placed on young Deaf and hard of hearing children’s learning of ASL, as the Ontario government’s Infant Hearing Program frequently did not provide ASL services to children who received cochlear implants or auditory-verbal therapy. This operational language policy of Ontario infant hearing screening and early intervention services was maintained despite evidence for the benefits that learning ASL confers on spoken and written language development in Deaf children. In this context, participation in a family ASL literacy program is a means for both supporting emerging ASL literacy in young children and resisting pathologizing Discourses (Gee, 2008) regarding signed language and Deaf identity. Through semi-structured interviews and observations of six individual families or parent-child dyads, the study documents participants’ encounters with gatekeepers who regulate Deaf children and their families’ access to ASL. At the same time, the setting of the ASL Parent-Child Mother Goose Program is presented as a Deaf cultural space and thereby a counter-Discourse to medical Discourses regarding Deaf identity and bilingualism. This space features the Deaf mother participants’ ASL literacy and numeracy practices and improvisations of ASL rhymes and stories to enhance their suitability for young children. The practices of the ASL Parent-Child Mother Goose Program leader also serve to define and support emergent ASL literacy in young children. In addition, a Deaf cultural space inside a broader context of public services to young Deaf children provides a means for the hearing mother participants to facilitate critical inquiry of issues surrounding bilingualism, ASL, and a Deaf identity. Collectively, the findings from this study highlight the benefits of emergent ASL literacy in Deaf children and their families, and provide an evidence-based rationale for Canadian governments and government agencies to better support this development.

Keywords: Bilingual education
American Sign Language
Early literacy
Deaf children
Early intervention
Advisor: Cummins, James
Putting Criminal Violence into Context: A Multi-level Analysis of the Correlates of Violence Severity among Early- and Late-start Mentally Disordered Offenders

The current research utilizes a multi-level analysis of historical, clinical, situational and neighbourhood factors to predict violence severity among persons with major mental illness. In addition, it draws on the typologies of offenders proposed by Moffitt (1993) and Hodgins and Janson (2002) to explore whether different predictors of violence severity exist for early-start, persistent offenders and late-start offenders. Finally, it compares early-start and late-start offenders with major mental illness to determine if differences exist in their criminal history, clinical presentation, motive for violence, crime-scene behaviours and neighbourhood backgrounds. A retrospective chart review of a mental health court support program in Toronto, Canada is utilized to explore the correlates of violence severity. Clinical charts and supplemental arrest records are content analyzed to extract data on arrestee/offender characteristics and on crime scene behaviours and tract-level data from the 2001 Canada Census is used to identify structural features of the neighbourhood environment of arrestees/offenders at the time of their arrest. Violence severity is measured using the Cormier-Lang System of Quantifying Criminal History (Quinsey, Harris, Rice, & Cormier, 1998). In total 1806 charts were reviewed and 245 subjects were subsequently included within the analyses. Using a variety of analytic techniques, the following results were obtained: 1) offense characteristics such as victim gender, victim-offender relationship, instrumental motive, and use of a weapon were the most robust predictors of violence severity while clinical factors such as diagnosis and comorbid clinical conditions were marginally significant predictors and historical factors such as previous violence and early-start offending were not significant predictors of violence severity; 2) context-specific measures accounted for more of the explained variation in violence severity than did individual-specific measures; 3) early-start and late-start offenders did differ with respect to history of violence, presence of a comorbid clinical condition such as a personality disorder or substance abuse and current life circumstances. Implications for theory refinement, clinical practice and program development are discussed and future avenues of research are considered.

Keywords: violence
mental disorder
mental illness
early-start offenders
late-start-offenders
offense characteristics
life circumstances
Advisor: Regehr, Cheryl
Algorithms in 3D Shape Segmentation

Surfaces in 3D are often represented by polygonal meshes and point clouds obtained from 3D modeling tools or acquisition processes such as laser range scanning. While these formats are very flexible and allow the representation of a wide variety of shapes, they are rarely appropriate in their raw form for the range of applications that benefit from their use. Their decomposition into simpler constituting parts is referred to as shape segmentation, and its automation remains a challenging area within computer science. We will present and analyze different aspects of shape segmentation. We begin by looking at useful segmentation criteria and present a categorization of current methods according to which type of criteria they address, dividing them into affinity-based, model-fitting, and property-based approaches. We then present two algorithmic contributions in the form of a model-based and a property-based segmentation approaches. These share the goals of automatically finding redundancy in a shape and propose shape representations that leverage this redundancy to achieve descriptive compactness. The first is a method for segmenting a surface into piece-wise ellipsoidal parts, motivated by the fact that most organic objects and many manufactured objects have large curved areas. The second is an algorithm for robustly detecting global and local planar-reflective symmetry and a hierarchical segmentation approach based on this detection method. We note within these approaches the variation in segmentations resulting from different criteria and propose a way to generalize the segmentation problem to heterogenous criteria. We introduce a framework and relevant algorithms for multi-objective segmentation of 3D shapes which allow for the incorporation of domain-specific knowledge through multiple objectives, each of which refers to one or more segmentation labels. They can assert properties of an individual part or they can refer to part interrelations. We thus cast the segmentation problem as an optimization minimizing an aggregate objective function which combines all objectives as a weighted sum. We conclude with a summary and discussion of the contributions presented, lessons learned, and a look at the open questions remaining and potential avenues of continued research.

Keywords: Segmentation
Meshes
Advisor: Karan, Singh
Energy and Momentum Consistency in Subgrid-scale Parameterization for Climate Models

This thesis examines the importance of energy and momentum consistency in subgrid-scale parameterization for climate models. It is divided into two parts according to the two aspects of the problem that are investigated, namely the importance of momentum conservation alone and the consistency between energy and momentum conservation. The first part addresses the importance of momentum conservation alone. Using a zonally-symmetric model, it is shown that violating momentum conservation in the parameterization of gravity wave drag leads to large errors and non-robustness of the response to an imposed radiative perturbation in the middle atmosphere. Using the Canadian Middle Atmosphere Model, a three-dimensional climate model, it is shown that violating momentum conservation, by allowing gravity wave momentum flux to escape through the model lid, leads to large errors in the mean climate when the model lid is placed at 10 hPa. When the model lid is placed at 0.001 hPa the errors due to nonconservation are minimal. When the 10 hPa climate is perturbed by idealized ozone depletion in the southern hemisphere, nonconservation is found to significantly alter the polar temperature and surface responses. Overall, momentum conservation ensures a better agreement between the 10 hPa and the 0.001 hPa climates. The second part addresses the self-consistency of energy and momentum conservation. Using Hamiltonian geophysical fluid dynamics, pseudoenergy and pseudomomentum wave-activity conservation laws are derived for the subgrid-scale dynamics. Noether’s theorem is used to derive a relationship between the wave-activity fluxes, which represents a generalization of the first Eliassen-Palm theorem. Using multiple scale asymptotics a theoretical framework for subgrid-scale parameterization is built which consistently conserves both energy and momentum and respects the second law of thermodynamics. The framework couples a hydrostatic resolved-scale flow to a non-hydrostatic subgrid-scale flow. The transfers of energy and momentum between the two scales are understood using the subgrid-scale wave-activity conservation laws, whose relationships with the resolved-scale dynamics represent generalized non-acceleration theorems. The derived relationship between the wave-activity fluxes — which represents a generalization of the second Eliassen-Palm theorem — is key to ensuring consistency between energy and momentum conservation. The framework includes a consistent formulation of heating and entropy production due to kinetic energy dissipation.

Keywords: Atmospheric science
climate models
subgrid-scale parameterization
conservation laws
Advisor: Shepherd, Theodore G.