VictorJuiz/thesis huggingface dataset:
Texts, culture and anti-colonial education, emerging Jamaican identity in the period of independence, 1962-1997

This thesis is a qualitative study of colonial and anti-colonial approaches to education and an examination of the use of textbooks in Jamaica's schools. Historically, textbooks, pedagogy, curriculum and educational policies have been mobilized to support the British colonial and neo-colonial project. Since Jamaica gained independence in 1962, successive governments have been challenged to deliver a system of education that reflects the aspirations of Jamaican peoples. However, these aspirations are increasingly complicated by globalization, structural adjustment policies, and the encroachment of the capitalist marketplace on local culture. This study focuses on how the use of local knowledge can disrupt hegemonic practices in the classroom and foster a stronger African-Jamaican cultural identity.
The neural basis of recovery from unilateral vestibular damage, role of the vestibular commissure

The vestibulo-ocular reflex (VOR) produces eye movements equal in magnitude and opposite in direction to head movements. The performance of the VOR is severely compromised after peripheral vestibular damage, but does recover. In this study the contribution of the contralesional horizontal canal is assessed via the response of ipsilesional secondary vestibular neurons to single shock electrical stimulation of the intact vestibular labyrinth. A significant decrease was observed in the efficacy of the excitatory commissural input to secondary neurons in the ipsilateral vestibular nucleus. It was observed that the operational range of the VOR increased as the applied peak stimulus velocity got larger. Similar behavior was also observed in the activity of vestibular neurons. Vestibular neurons were found to have a sensitivity that decreased with increasing stimulus amplitude. In addition, the three neurons that experienced cut-off during ipsilesional rotations had a linear range that increased with increasing stimulus amplitude.
Robust state estimation and control of highway traffic systems

In this thesis, a modified second-order continuum model is used to describe the traffic behaviour along highways. The model is identified and verified using several sets of traffic measurements collected from a major highway in metropolitan Toronto, Canada. A robust nonlinear sliding mode observer is developed to generate estimates of average velocity and density for a segment of a highway within a corridor, given loop detector measurements at the end-points of the segment. The sliding mode approach has several advantages over other estimation techniques such as the Kalman Filtering including proof of estimate convergence and simplified computations. However, the primary advantage is the robustness of the observer with respect to unmodelled dynamics and disturbances. Unmodelled dynamics are associated with the traffic factors whose effects cannot be captured (properly) in the traffic flow models, e.g., road geometry and weather conditions. On the other hand, model disturbances such as unavailable (not measured) traffic flow at a ramp or measurements provided by a faulty detector can also create unpredictable traffic states. Based on the presented traffic model, a systematic design procedure is developed to make the observer robust with respect to the modelling uncertainties and unavailable traffic states. Simulation and experimental results show the effectiveness of the proposed observer in estimating the states of a highway traffic system. Moreover, a new decentralized state feedback linearizing controller for ramp metering using variable structure control is presented. The main aim is to develop a robust controller to locally stabilize freeway traffic despite the presence of disturbances and modelling errors. Simulation results show that the proposed controller provides improved performance in achieving the design objectives over other existing ramp control strategies such as neural network and linear feedback controllers.
Application of neural network analysis to the thickness-shear mode chemical sensor

This thesis presents the application of artificial neural networks (ANN) to the self-referent calibration of thickness-shear mode (TSM) acoustic wave chemical sensors. Spectrum analysis of impedance measurements affords complete characterisation of the TSM sensor, which includes the use of the Butterworth-Van Dyke (BVD) equivalent circuit to quantify the electrical responses. The multi-parametric nature of this method and a novel weight-adjustment procedure, applied to ANN calculations, were utilised to effect a method of calibration in the presence of interferents. A network is trained, using exemplary I/O data acquired for a potassium chloride (KCI) system, to predict unknown outputs 'i.e. ' concentration, given four sets of measured inputs 'i.e.' series resonant frequency (FS), parallel resonant frequency (F P), motional capacitance (Cm) and motional resistance (R m). The trained and tested networks achieved high predictive efficiency with errors in the range of 2%-7%. An interferent, ethanethiol, is added to test the robustness of the trained network and was found to adversely affect the predictive ability of the network. The magnitudes of the weights, which are associated with the set of inputs deemed to be most affected by the interferent (FS), are adjusted to minimise this deterioration. The resultant network, calibrated for the interferent, achieved a similar predictive efficiency for adulterated samples as that achieved by the original network for unadulterated samples. This calibration procedure was extended to a dual-interferent system in which two input variables are affected. A significant decline in predictive ability was observed for the unadjusted network, render it practically unusable. A two-point weight adjustment process was performed on the affected weights with considerable success but the predictive ability did not come close to the original level. The manipulation of two out of four input parameters may have over-extended the resources of the network but may prove to be more amenable for a larger network. A parallel project was effected in which a chemically-selective platform was immobilised on a TSM device following activation with bifunctional thiols. The optimal surface activation scheme was found to be the self assembly of a mixture of bifunctional thiols of different chain lengths. An amino-terminated 25-mer DNA single strand was successfully coupled to the distal carboxylic group via carbodiimide chemistry. The viability of the immobilised DNA receptor was demonstrated through a hybridisation experiment with a complementary DNA fragment. In addition, the multi-parametric nature of network analysis proved to be sensitive to the hybridisation kinetic and a subsequent, capacitive-based conformational change in the coupled strands.
Development of a helicopter emergency maneuvers trainer

This thesis describes the development of a generic helicopter code to be used as a helicopter emergency maneuvers trainer for piloted flight simulations. The helicopter employed in the current simulation is a Bell 205, with a two-bladed teetering rotor and skid-type landing gear. In order to create a model with clearly defined modules and full documentation, the physical model was implemented using the commercial software package MATRIXx, a graphical based program capable of simulating dynamic systems and able to generate C-code for use in a real-time simulation. The simulation model has been implemented and run in real-time on the UTIAS Flight Research Simulator. Piloted simulations have demonstrated a wide flight envelope including typical operating regimes as well as basic emergency maneuvers.
Spatial and temporal variability in a hyporheic zone, a hierarchy of controls from water flows to meiofauna

The hyporheic zone beneath a single 10 m-long riffle of a gravel-bed stream was sampled intensively between August 1996 and November 2000. The overall aims were to identify the factors controlling surface-subsurface exchange flows, biogeochemical processes and meiofaunal distributions in the hyporheic zone, and to quantify the effects of hyporheic processes on inorganic nitrogen and dissolved organic carbon (DOC) concentrations in the stream. From among a large number of factors suggested by other authors, three key factors were identified that together control surface-subsurface exchange flows: the hydraulic conductivity of the alluvial sediments, the hydraulic gradient between upstream and downstream ends of the riffle, and the discharge flux of ground water into the alluvium. Each of these factors changes with season, causing a reversal of subsurface hydraulic gradients and a great reduction in exchange flows during fall to spring. A wide variety of aerobic and anaerobic microbial processes was found to occur in the hyporheic zone. Although oxygen inhibits anaerobic processes, denitrification, ferrous iron reduction and sulphate reduction all occur in oxygenated sediments, probably because sediment biofilms create anaerobic microenvironments. Therefore, denitrification is controlled more strongly by nitrate concentration than by oxygen at this site. The hyporheic zone at this site is a sink of DOC and inorganic nitrogen, in contrast to many streams. Loss of inorganic nitrogen at this site is a result of slow subsurface flow rates, rapid oxygen uptake and high surface water nitrate concentrations, which together favour denitrification. This supports the current theory that seeks to explain when and where the hyporheic zone will be a source or sink of inorganic nitrogen. At this site, however, only 0.01-0.2% of surface water discharge is exchanged with the subsurface along the 10 m rifle, indicating that removal of surface water nitrogen by hyporheic exchange is negligible in this stream. Abundance and taxon richness of meiofauna are controlled primarily by depth. Physicochemical parameters associated with surface water control distributions to a lesser extent, but measures of available food, such as particulate organic matter, and abundance and activity of sediment-bound bacteria, show no correlation with any measure of the meiofaunal community.
Unmasking White complicity/innocence, critical White studies and the implications for rethinking schooling

In this thesis I examine the literature in the field of critical White studies and explore the pedagogical implications for rethinking schooling. I argue that an interrogation of Whiteness is vitally important to informing anti-racism theory and praxis. As White educators our task is to dismantle the pervasive power of Whiteness to define normalcy in our educational institutions. This entails a rigorous and critical problematization of Whiteness as systems of domination that not only marginalize racialized "Others" but unfairly privilege Whites. I analyse processes of transforming Whiteness through deconstructing White positionality and Eurocentric hegemony. Developing a White anti-racist consciousness involves probing our own complicity in White supremacy/racism to see how we have been affected by histories of colonialism and imperialism and are vested in systems of power and privilege. In transforming schooling, space must be created for critical pedagogies of Whiteness within an integrative anti-racism framework.
Role of embryonic prostaglandin H synthase-catalyzed free radical formation and reactive oxygen species-mediated macromolecular damage in chemical teratogenesis

Teratogenic xenobiotics such as thalidomide, phenytoin and benzo[a]pyrene (B[a]P) may be bioactivated by prostaglandin H synthases (PHSs) to free radical reactive intermediates that initiate the formation of reactive oxygen species (ROS), which oxidatively damage cellular macromolecules. Using electron paramagnetic resonance spectrometry, the mechanism of free radical formation for phenytoin and related analogs was evaluated in an 'in vitro' system with purified PHS-1 and the free radical spin trapping agent alpha-phenyl-N-'t'-butylnitrone (PBN). PHS-catalyzed, carbon-centred free radical formation was detected for phenytoin and all its analogs. For phenytoin, both a putative unstable nitrogen-centered and a stable carbon-centered free radicals were detected, which were capable of oxidizing DNA. This provides the first direct chemical evidence for PHS-catalyzed bioactivation of phenytoin and related teratogens to a free radical intermediate that initiates DNA oxidation, which may constitute a common molecular mechanism of teratologic initiation. The developmental role of PHS-1 and -2 is poorly understood. Using PHS-2 knockout mice, we determined that embryonic PHS-2 is expressed constitutively during organogenesis, and contributes substantially to B[a]P bioactivation and teratogenicity, evidenced by an increased incidence of malformations and postpartum lethality in both +/+ and +/- fetuses exposed 'in utero' to B[a]P compared to their -/- littermates. Similarly, PHS-1 knockout mice were less susceptible to phenytoin- and B[a]P-initiated embryopathy, and to phenytoin-initiated DNA oxidation. Although deficiencies in PHS-1 and -2 protected against xenobiotic teratogenesis, maternal administration of a chemical known to specifically inhibit PHS-1 'in vitro' resulted in potentiation of phenytoin teratogenicity, suggesting that these inhibitors may not be suitable for 'in vivo' use during pregnancy. The once-abandoned human teratogen thalidomide has found new therapeutic uses, even though its mechanism of teratogenesis remains unclear. In rabbits (a susceptible species), thalidomide initiated embryonic DNA oxidation and teratogenicity, both of which were abolished by pretreatment with PBN. Conversely, in mice (a resistant species) thalidomide did not enhance DNA oxidation, providing the first insight into an embryonic determinant of species-dependent susceptibility. These results constitute the first direct evidence that the teratogenicity of thalidomide may involve free radical-mediated oxidative damage to embryonic cellular macromolecules. The results from this thesis suggest that the mechanism of teratogenesis for many xenobiotics may involve embryonic PHS-catalyzed bioactivation to a free radical intermediate, resulting in ROS-dependent oxidative damage to embryonic cellular macromolecules.
Effects of cyclic current modulation on cathode materials for the hydrogen evolution reaction

Commercial industrial water electrolysers often operate discontinuously. The efficiency of the hydrogen evolution reaction (HER) requires cathode materials to have a high intrinsic electrocatalytic activity. Under intermittent operation, it is desirable that both the activity and the structure of the material remain stable. In this study, intermittent industrial water electrolysis conditions were simulated in the laboratory with a cyclic current modulation test. A conventional material, commercially pure nickel sheet, and a novel material, amorphous $\rm Ni\sb{50}Co\sb{25}P\sb{15}B\sb{10}$ melt-spun ribbon were evaluated in 8 M KOH electrolyte at 70$\sp\circ$C. The electrochemical activity of the material was determined with Tafel (overpotential vs. current density) plots and surface structure was assessed with scanning electron microscopy, energy dispersive x-ray analysis and x-ray photoelectron spectroscopy. Nickel initially deactivated at constant current due to hydrogen absorption and remained deactivated during cyclic modulation. In a lower-purity electrolyte, nickel partially recovered activity during cycling due to surface growth from electrodeposition of iron impurities. $\rm Ni\sb{50}Co\sb{25}P\sb{15}B\sb{10}$ deactivated in a similar manner to nickel but partially recovered activity with cyclic modulation. This is attributed to Ni enrichment at the surface via in-situ electrochemical dealloying; elements with lower HER activities were depleted. The amorphous alloy was embrittled under HER conditions. For as-polished and cyclically modulated nickel and as-polished $\rm Ni\sb{50}Co\sb{25}P\sb{15}B\sb{10},$ the rate-determining step for the HER at low overpotentials is H adsorption and at high overpotentials is H absorption. For cyclically modulated $\rm Ni\sb{50}Co\sb{25}P\sb{15}B\sb{10},$ the rate determining step of HER at low overpotentials is H absorption. With cathodic polarization and cyclic modulation, the surfaces were micro-roughened. After cathodic polarization, surface films on Ni metal and $\rm Ni\sb{50}Co\sb{25}P\sb{15}B\sb{10}$ were thickened and had a hydroxide character and $\rm Ni\sb{50}Co\sb{25}P\sb{15}B\sb{10}$ had an increased ratio of Ni:Co.
Unit-delay deadbeat control of a high bandwidth active power filter

This thesis presents a novel unit-delay digital deadbeat current controller for a shunt active power filter (APF) based on a voltage-sourced converter (VSC). This current controller architecture increases the APF current-tracking bandwidth without increasing the VSC switching frequency. Previous APF deadbeat controllers are implemented in high-performance digital signal processors (DSP), but demonstrate a current-tracking delay of two sample periods. One sample period delay is due to current controller computation time. The second sample period delay represents VSC actuation time. In the proposed scheme, the current-tracking feedback control calculations are executed in programmable digital logic. Economical asynchronous arithmetic circuitry effectively eliminates computation delay, resulting in unit-delay reference tracking. A low-cost microprocessor provides fundamental frequency feed-forward disturbance rejection, as well as other supervisory functions. Experimental results from a laboratory implementation verify the desired operation of the APF current control system.
Clinical comparison of two corneal storage media

'Objective'. To compare the clinical outcome of corneal transplantation performed with tissue stored in two different storage media: Chen Medium (CM) and Optisol GS. 'Design'. Prospective, randomized, double masked trial. 'Participants and setting'. Ninety patients undergoing corneal transplantation recruited from the Cornea and External Disease Service, the Department of Ophthalmology, Toronto Western Hospital, University Heath Network. 'Intervention'. Donor cornea pairs were stored one in CM and the other in Optisol GS, transplanted into recipients, and followed postoperatively for 3 months. 'Main outcome measures'. The primary outcome was percentage corneal endothelial cell loss (ECL) measured 3 months after transplantation. Secondary outcomes were corneal thickness, epithelialization, measured at postoperative days 1, 7, 30, and 90, as well as primary and secondary graft failure. 'Results'. Mean percentage ECL 3 months postoperatively was 4.9% higher for corneas stored in Optisol GS compared to CM. The associated 95% confidence interval was -3.4% to 13.2%. Average thickness values at postoperative days 1, 7, 30, and 90 for corneas preserved in CM were 721[mu], 661[mu], 568[mu], and 548 [mu]; respectively. The corresponding values for corneas stored in Optisol GS were 691[mu], 656[mu], 567[mu], and 562[mu]. Repeated measures analysis did not demonstrate a difference between the two storage media. Eighty-eight percent of the corneas stored in each medium achieved epithelialization of 75%-100% surface area within one week after transplantation. No primary donor failures occurred in either group. One graft that was preserved in CM failed during the study period. 'Conclusion'. The clinical outcomes of corneal transplantation with tissue that was preserved in CM were similar to these of grafts preserved in Optisol GS.
Empirical essays on behavioural responses to taxation

This thesis addresses empirical questions on the behavioural response to taxation. The first essay develops a model of contributions to tax-preferred savings accounts. Contributions to tax-preferred savings accounts are typically constrained by a contribution limit. I develop a simple life-cycle model in which tax filers exhibit "use-it-or-lose-it" behaviour. This connects current contributions to future contribution limits, which leads to the result that an increase in contribution limits can decrease contributions. Using a panel of Canadian tax filers I find empirical evidence that provides support for the model--larger future contribution room is associated with smaller contributions. The second essay studies further questions on tax-preferred savings accounts. I find that taxes play a role in the decision to contribute to a Registered Retirement Savings Plan, but the effect of taxes is smaller than suggested by the existing literature. I also find evidence that the sensitivity of participation to future marginal tax rates increased after the introduction of the carryforward. This is consistent with the model presented in the first essay. The final chapter looks at tax incentives and fertility. This essay exploits a unique reform in the province of Quebec that paid benefits following the birth of a new child. I implement two approaches to estimation. First, I use a quasi-experimental comparison of treatment and control groups to estimate the effect of changes in policy. Second, I take advantage of the policy reforms to construct an instrument that enables me to address the endogeneity of fertility to income-tested benefits. I find a strong and robust effect of fiscal incentives on fertility. In an extension, I use this policy variation to form an instrument to study the effect of family size on female labour supply, finding results consistent with the existing literature.
The help-seeking of violent crime victims

In this research I examine the help-seeking strategies used by male and female crime victims. Consideration of the help-seeking strategies used by victims in dealing with violent crime may provide insight into other decision-making processes, including reactions to other life traumatizing events. The analytic framework for this dissertation integrates research on intimate partner violence and police reporting with the wider help-seeking literature. This integration highlights the way in which victims actively engage in help seeking, given social locations that both limit and facilitate the ability to seek social support. The impact of gender, race and the victim-offender relationship on decisions to seek help are examined within this framework. Although most victims of violent crime do not call the police, many victims rely on family, friends, medical, social service and mental health interventions in dealing with the consequences of violent crime. The findings from my research are in accord with the wider help-seeking literature that suggests that those who seek help from family and friends and the users of mental health, social service and self-help groups tend to be female. In contrast, most male victims do not seek help. When men do seek help, they are more likely to call the police than to call upon family and friends. The victim-offender relationship is also an important predictor of help-seeking decisions. Attacks by known offenders lead to help-seeking strategies that rely primarily on family and friends. My research also suggests that female victims of intimate partner violence, and in particular white women, will use a substantial help-seeking strategy that includes help-seeking from family, friends, mental health professionals, social service agencies and the police. In contrast, white women attacked by strangers are the most likely to use a strategy that primarily relies on calling upon the police in dealing with their experiences with violent crime. These findings suggest that the effects of gender, race and the victim-offender relationship on help seeking decisions are not easily conceptualized by contrasting those who report to police with those who do not. The theoretical, methodological and policy implications of these findings are discussed.