VictorJuiz/thesis huggingface dataset:
Experimental investigation of energetic interactions between aluminum and water

The interaction between aluminum and water is studied experimentally. A capacitor discharge system is used to heat a 17 mm long aluminum sample submerged in water in a test chamber. Two types of aluminum samples are used, wire and ribbon. The ribbon geometry provides a 40.1% increase in surface area over the cylindrical wire. Results show that the critical energy threshold for the ribbon, above which a sustained combustion is observed, is about 500 J/g less than that of the wire sample. The increased surface area serves to enhance the degree of chemical reaction between aluminum and water. Experiments are also performed using wire samples in hot water to investigate the effects of coolant subcooling. The critical threshold is not affected significantly when compared to results from experiments in cold water. However, there is an increase in the interaction strength when the energy delivered to the sample is above the threshold of 2250 J/g.
Threonine and phenylalanine metabolism in the human neonate

Low birthweight (LBW) neonates are vulnerable to amino acid deficiencies and excesses due to their immaturity. Human milk protein is believed to contain an appropriate balance of amino acids for infants. Concern has been raised by the observation that plasma threonine concentration of LBW infants fed whey dominant formulas was twice as high as those fed human milk. Conversely, casein dominant formula feeding was associated with elevated plasma aromatic amino acid concentrations. In order to further explore threonine and phenylalanine metabolism in response to feeding, threonine and phenylalanine flux and oxidation to CO$\sb2$ were determined in 18 LBW infants (gestational age 31 $\pm$ 2 weeks, birthweight 1720 $\pm$ 330 g) using 18 h constant oral infusions of L- (1-$\sp{13}$C) threonine and L- (1-$\sp{13}$C) phenylalanine. Infants were fed one of three formulas that differed only with respect to the whey:casein ratio (60:40, 40:60, 20:80) or their mother's milk (MM). Threonine intake on 60:40 formula was excessive, compared with MM, based on higher threonine flux (221.4 vs 170 $\mu$mol/kg/h) and plasma threonine concentration (419 vs 208 $\mu$mol/L). The 20:80 formula provided a more appropriate threonine intake but was associated with the occurrence of transient tyrosinemia which was studied isotopically. Formula fed infants oxidized less threonine compared to infants fed MM, (17.1 vs 24.3% of intake) and this finding accounted for the differences in plasma threonine concentrations among feeding groups. The influence of diet on threonine dehydratase activity was then investigated in piglets of various ages. Threonine dehydratase activity was shown to be lower in piglets fed artificial formula compared with sow-fed piglets during the suckling period. Degradation of excess threonine was investigated in the adult human. Plasma threonine concentration increased more in response to an increment of threonine that was provided as free amino acid vs as a constituent of protein. These results were concluded to reflect the influence of both protein turnover and threonine oxidation on threonine pool size. In contrast to adult humans, LBW infants showed a more limited capacity to degrade excess threonine contained within a whey protein source. This investigation provided insight into the metabolism of threonine and phenylalanine in response to feeding that could serve towards the improvement of infant formulas.
Cultural perspectives of the urban forest

Due to urbanization, Canadian cities impact the environment negatively. A well maintained urban forest (UF) ameliorates these impacts. Given most trees grow on private property, it is difficult to manage the UF as all residents influence UF management. Conflicts in the UF seem to occur between cultural groups. This study tested the hypothesis that culture influences the way a community perceives the UF using four methodologies. A vegetation inventory in Toronto shows significant differences in both the number and species of tree cover in different cultural communities. Interviews with residents of different backgrounds shows marked differences in landscape tastes. Interviews with urban forest professionals shows varying levels of understanding of cultural differences, and research done on the landscape history of different cultures shows vastly different urban planning traditions. The study recommends that planners be educated to these differences, and that residents need be educated about benefits of the UF.
The design, development and evaluation of a critical language awareness program for preservice teachers

The need for preservice teachers to become more aware of the role language in shaping and being shaped by power relations has been identified. The purpose of this study was to develop a Critical Language Awareness Program for Preservice Teachers and evaluate its potential educational value. The evaluations were conducted through focused interviews with educational experts who are familiar with the theory underlying the program and the learning needs of preservice teachers. The study revealed that in the experts' opinions, the program would be useful and have educational value for preservice--teachers. However, several minor problems with the program were identified, and it is recommended that they be corrected before the program is implemented at a Faculty of Education.
Study of atmospheric plasma spray process with the emphasis on gas shrouded nozzles

An atmospheric plasma spraying process is investigated in this work by using experimental approach and mathematical modelling. Emphasis was put on the gas shrouded nozzles, their design, and the protection against the mixing with the surrounding air, which they give to the plasma jet. First part of the thesis is dedicated to the analysis of enthalpy probe method, as a major diagnostic tool in this work. Systematic error in measuring the stagnation pressure, due to a big temperature difference between the plasma and the water-cooled probe, is investigated here. Parallel measurements with the enthalpy probe and an uncooled ceramic probe were performed. Also, numerical experiments were conducted, using the k-$\varepsilon$ model of turbulence. Based on the obtained results, a compensating algorithm for the above error is suggested. Major objective of the thesis was to study the plasma spraying process, and potential benefits from using the gas shrouded nozzles. Mathematical modelling was used to perform the parametric study on the flow pattern inside these nozzles. Two nozzles were used: a commercial conical nozzle, and a custom-made curvilinear nozzle. The later is aimed towards elimination of the cold air entrainment, recorded for the conical nozzle. Also, parametric study on the shrouding gas and its interaction with the plasma jet was carried out. Two modes of the shrouding gas injection were tested: through sixteen injection ports, and through a continuous slot, surrounding the plasma jet. Both nozzles and both injection modes were thoroughly tested, experimentally and numerically. The curvilinear nozzle completely eliminates the cold air entrainment and yields significantly higher plasma temperature. Also, injection through the continuous slot resulted in a much better protection of the plasma jet. Both nozzles were used to perform the spraying tests. Obtained coatings were tested on porosity, adhesion strength, and micro-structure. These tests indicated better micro-structure of the coatings sprayed by the curvilinear nozzle. Also, their porosity was significantly lower, and the adhesion strength was higher for more than 25%. The overall results suggest that the curvilinear nozzles represent a much better solution for the gas shrouded plasma spraying.
A numerical model of the motion of a curved flexible fibre in a shear flow

A general method to simulate the motion of initially curled flexible fibres in 2-D flows is developed. Equations of motion are formulated for a curled elastic fibre in a fluid flow using Hamilton's Principle. The non-linear integro-differential equations contain an unknown deflection variable that is discretized using a half-range Fourier Sine series representation. The first (kinematic) approximation is obtained by setting the inertia terms to zero. The resulting inertialess equations are solved using a Runge-Kutta method implemented in a C++ code. The validity of the numerical model was tested against analytic theory and existing transient results for essentially straight fibres, i.e. fibres with small radii of curvature and large angles. Excellent agreement was achieved. The numerical model was then applied to simulate fibre motion into a screen slot. For similar fibre parameters, it was found that significantly more curled fibres entered the slot than their straight counterparts.
Distribution and plant uptake of arsenic and uranium at two low-level radioactive waste management sites

This study examined the distribution and plant uptake of arsenic and uranium at two low-level waste management sites: the Welcome and the Port Granby Waste Management Facilities. Environmental samples, such as vegetation, surface soil, and water, were collected from both sites and analyzed for As and U using neutron activation analysis. There was slight surface contamination of arsenic and uranium at both of the waste management sites. A comparison of the concentration ratios for As indicated greater uptake of As at the Port Granby site. The As plant-soil relationships for the two sites suggested the presence of differing arsenic species. The plant concentration ratio for U was not constant at low concentrations ($<$20 $\mu$g/g), and U was accumulated extensively in the roots of the plants. In general, U appeared to be more readily available for plant uptake than As at these sites.
The role of E-selectin and P-selectin in T lymphocyte migration to inflammation using a novel quantitative mouse model

The roles of E-selectin and P-selectin in T lymphocyte migration to cutaneous inflammatory reactions were investigated. Within 22 hours after i.v. injection, $\sp{51}$Cr-labelled splenic T lymphocytes migrated to cutaneous inflammatory reactions induced by IFN-$\gamma$ and TNF-$\alpha$ and even in greater numbers to inflammatory reaction induced by Con A or a combination of IFN-$\gamma$ and TNF-$\alpha.$ In anti-E-selectin mAb treated and in E-selectin deficient mice IFN-$\gamma,$ Con A and IFN-$\gamma$ plus TNF-$\alpha$ induced T cell accumulation was inhibited by approximately 55%, but not TNF-$\alpha$ induced T cell accumulation. In anti-P-selectin treated and in P-selectin deficient mice T cell accumulation in most of the lesions was unaffected. Combined, anti-E-selectin and anti-P-selectin inhibited T cell accumulation in all four types of lesions. Furthermore, T cell migration to Con A was inhibited by 80%, significantly more than by anti-E-selectin alone. Results from E-selectin and P-selectin deficient mice confirmed these observations.
Development of a paediatric prosthetic hand with a two-degree-of-freedom thumb

A new paediatric prosthetic hand with multiple grasping patterns was presented in this thesis. The purpose of this new design was to improve performance of conventional child prostheses by providing a more functional hand. Some special mechanisms were designed, which allowed the thumb of the new hand to be set in different positions. These positions correspond to common grasping patterns of the natural hand palmar, lateral, and cylindrical/spherical. A three dimensional computer simulation model was built to obtain proper initial positions of the thumb and fingers. A working prototype was fabricated. Initial tests focused on the mechanical properties of the hand. Test result indicated that this new hand met design requirements. A preliminary functional evaluation was carried out with a child alternatively wearing a conventional prosthetic hand and the experimental hand. The purposes of this investigation were to examine the performance of the new hand and to determine additional functional benefits derived from using the hand. Results from the clinical evaluation indicated that the new hand performed as well as a conventional hand. It had added functional benefits in that compensatory body movements were minimized, and a larger variety of objects could be held with increased stability. Contributions of this work include development of the first childsized prosthetic hand in which the thumb can be placed in different positions. A novel mechanism was designed and built to ensure locking of thumb rotation during the performance of grasping activities.
Translocation of IgM-antigen receptor associated signaling molecules into the membrane skeleton during early B cell activation

Membrane Immunoglobulin (mIgM) the component of the B cell receptor which provides specificity for antigen has been shown to associate with the cytoskeleton upon receptor cross-linking. In an attempt to understand the role of this interaction during signaling, I have asked the question whether the signaling components of the B cell receptor accumulate in the membrane skeleton along with mIgM. Interestingly, I have shown that tyrosine phosphorylated Ig$\alpha$ translocates to the membrane skeleton as part of the B cell receptor complex after mIgM cross-linking. The maximum levels of tyrosine phosphorylated Ig$\alpha$ and other substrates correlated with the maximum levels of mIgM in the membrane skeleton fraction. Furthermore, I have demonstrated that the Src family protein tyrosine kinase Lyn and the cytoplasmic tyrosine kinase Syk are found in the membrane skeleton following cross-linking of the B cell receptor. These data suggest that mIgM translocating to the membrane skeleton provides the vehicle for active signaling molecules to be recruited to this subcellular location. This may promote B cell activation events by providing optimal interactions between signaling molecules supported by the cytoskeletal matrix.
A model for the translational vestibulo-ocular reflex

The vestibular system is the system of balance. The vestibulo-ocular reflex (V0R) moves the eyes in response to head movements by using information from the angular motion detectors, the semicircular canals (AVOR), and linear motion detectors, the otolith organs (TVOR). In order to move the eyes, the oculomotor neurons are known to require signals in phase with velocity and position. However, the primary afferent signal carrying information from the otolith organs is in phase with acceleration. To complicate matters, the TVOR is a function of target distance and target position and the otoliths are also sensitive to gravity. The model in this thesis differentiates the primary afferent signal making it in phase with velocity. The signal's gain is then adjusted and is merged with the canal signal and it is the combination of the two signals that will reach the motor neurons. Tilts on the other hand cause the gravity vector to shift with the respect to the otolith organs. How do central mechanisms differentiate between an imposed tilt and an imposed linear acceleration. We have proposed that if both the otolith organs, the utricle and the saccule, are taken into account, then the ambiguity in the signal is removed. A simple function is presented that considers different cases of tilt and translations and eliminates any ambiguity.
An analysis of the nature and implementation of policies concerning cultural and racial bias in curriculum materials

In response to growing cultural and racial diversity in Canadian schools, ministries and school boards have developed policies concerning racial and cultural bias in curriculum materials. This thesis examines the nature, implementation and outcome of these policies. Data were collected from nine of the provincial ministries of education and ten school boards across Canada known to have multicultural or race and ethnic relations polices in place. In addition, pilot studies of implementation were conducted in two Ontario school boards. Using the process of analytic induction, the data were examined according to a typology of public policy and within a framework of implementation theory. Findings revealed that bias policies elicited a range of individual responses which cut across traditional organizational cultures. Furthermore, it was found that personal commitment, political pressure and cultural reinforcement were, alone or in combination, necessary precursors to the implementation of bias policies.
A comparative study of the perspectives of African and Euro-Western educators on the idea and practice of sustainable development

Sustainable development is an ambiguous term, diverging in meaning depending upon an individual's gender, race, ethnicity, class, and lived experiences. This study comparatively examines the meaning of, obstacles to, and alternatives for sustainable development from African and Euro-Western perspectives. A qualitative approach, using both Critical Social Science and Feminist Social Research, was used in eight semi-structured interviews. These interviews drew upon each participants' personal and professional experiences, and subsequent beliefs surrounding sustainable development in an African context. In the final analysis, all of the participants agreed that Western domination and its obsession with materialism and consumerism is not sustainable on a global level. Categorically speaking, the Euro-Western educators were largely consumed with Western domination and its iniquitous effects on Africa, while the African educators emphasized a holistic and indigenous approach to sustainable development.
Effects of post-hardening fertilization on early growth and nutrition of planted black spruce seedlings

Biomass and nutrient status of black spruce (Picea mariana (Mill.) B.S.P.) seedlings were examined during and after exposure to five hardening fertilization regimes: conventional (C), constant loading (CL), exponential (E), moderate exponential (EL) and high exponential loading (2EL) treatments (delivering respectively 0, 32, 0, 32, 64 mg N seedlings$\sp{-1}$) to assess the effect of fertilizer supplementation on early outplant growth. Under conventional (C), constant loading (CL) and exponential (E) regimes the seedlings experienced nutrient dilution, particularly of K, indicating soil nutrient levels were rapidly depleted because of plant uptake and lack of fertilizer during the hardening phase. Nutrient concentrations remained relatively stable throughout the hardening period in the moderate exponentially nutrient loaded (EL) and high exponentially loaded (2EL) seedlings, signifying sustained, steady-state nutrient conditions. The result indicated that plants treated with high and moderate exponential fertilizer schedules effectively countered nutrient dilution without causing nutrient toxicity. High preplant nutrient reserve in high exponentially loaded (2EL) seedlings resulted in increased field growth by as much as 33-35%, over nonloaded (C) seedlings. These plants were better able to translocate readily available internal reserves and to fix more carbon. Thus, exponential loading during post-hardening is an effective practice in ensuring steady-state nutrient culture of plants, and contributes significantly to improved outplanting performance of conifer seedlings.
Structure and memorability of Web sites

This thesis addresses the design and use of multimedia on the World Wide Web. An experiment was designed and carried out that logged the paths of users on four different Web sites, representing a combination of site sizes and structures. The more hierarchically structured sites received higher numbers of visits and accesses. Maps that subjects created after using Web sites were almost exclusively hierarchical. The number of visits to a node was a better predictor of memorability and judged importance than was the connectivity of the node. The best predictor for node visitation was the level of the node in the hierarchy. This thesis developed a methodology for studying effects of Web site browsing on recall. The results suggest that people expect hierarchical structure on the Web, and that connectivity based measures for identifying landmarks are inapplicable to the Web. Design guidelines and future research based on this work are also proposed.
Distribution and time evolution of starspots on VW Cephei studied with Doppler imaging

Maximum entropy Doppler images of VW Cephei produced from seven datasets of simultaneous photometric and spectroscopic data are presented. The observations were obtained at the David Dunlap Observatory from March 11, 1991 to May 13, 1993. The photometric observations were made in the Johnson-Morgan, Kron-Cousins BVRI system, and the spectroscopic observations were made at NaD and $H\alpha$ on alternating nights. The data were reduced using algorithms requiring little or no user intervention. Algorithms for automated dispersion fitting, cosmic ray removal, and telluric line removal are presented in detail. An improvement to the Optimal Spectrum Extraction Algorithm of Horne (1986), allowing better extraction under conditions of high sky background, is presented and used. The Doppler images were produced using maximum entropy regularisation, fitting geometrical and orbital parameters of the contact binary at the same time as spots using both the spectroscopic and photometric data to constrain the models. Spots were modeled as being 3500 K in temperature, fractionally covering each surface element of the system to different amounts. These models fitted the observational data very well.
Explicit and implicit memory for new associations between familiar faces

Associative memory for familiar faces was investigated in three experiments. Pairs of familiar faces were presented elaborative or nonelaborative encoding; memory for these pairs was tested by presenting old-intact pairs, old-recombined pairs, and pairs consisting of one or two new faces. Experiment 1 tested explicit memory for new associations and showed that recognition was best for the old-intact pairs under elaborative encoding conditions. On an implicit test of memory (Experiment 2), associative priming effects were not obtained despite using a familiarity judgment task similar to one that has produced associative priming effects with words (e.g. Goshen-Gottstein & Moscovitch, 1995a). Experiment 3 showed that the lack of associative priming could not be attributed to the nature of the familiarity judgment task as similar results were obtained when a face/nonface judgment task was used. It is proposed that the different associative priming effects obtained with the two types of stimuli may arise from differences in the modular perceptual representation systems for faces and words.
Diastereoselective intermolecular (4+3) cycloadditions between chiral furans and oxyallyl cations, a route to enantiomerically enriched cycloadducts

Oxabicyclo(3.2.1) octenes have served as valuable intermediates for the construction of various natural products and their analogues. Until recently, methods for their asymmetric construction have been limited to desymmetrization reactions. Thus, if their scope and utility are to be expanded in organic synthesis, then the development of alternative strategies for their asymmetric construction is warranted. This thesis describes a practical and general strategy for the synthesis of unsymmetrical oxabicyclo(3.2.1) octenes as single enantiomers via a diastereoselective intermolecular (4+3) cycloaddition reaction between chiral 2-furylcarbinols and oxyallyl cations. It was found that deprotonation of the furylcarbinol's hydroxyl moiety with a divalent organometallic reagent and subsequent cycloaddition with the oxyallyl cation provides access to cycloadducts in high diastereomeric excess ($\geq$90%). Interestingly, the stereochemistry of the products dictates that the reaction not only arises from a chelate controlled facially selective cycloaddition but also from an unprecedented extended transition state. Hence, previously unavailable cycloadducts can be made in good yields ($\leq$80%).