title: Endothelin response and reactive oxygen in coronary artery smooth muscle

contributor:
Grover, A.K.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: Endothelin-1, the most potent endogenous vasoconstrictor peptide known, plays a key role in regulating coronary artery vascular tone. Reactive oxygen species generated during cardiac ischemia-reperfusion cause several types of damage to cardiovascular tissues, in particular to the intracellular Ca2+ -regulating mechanisms. This thesis explores the endothelin-1 receptor types in coronary artery smooth muscle and their signal transduction pathways and the effects of reactive oxygen on them . Endothelin-1 mediated contraction of de-endothelialized pig coronary artery rings. There are two types of endothelin receptors known: ETA and ETB . Using ETA and ETB receptors selective agonists and antagonists, the contraction mediated by ETB -receptors was approximately 20% and the remaining was due to ETA receptors. Ca2+ pools mobilized by the two receptors were similar except that the ETB receptor activation utilized more of the intracellular Ca2+ pool than the ETA activation. 125 I-ET-1 binding to microsomes isolated from smooth muscle of this artery also showed ETA and ETB binding sites with most binding occurring at the ETA sites. Thus, the endothelin-1 induced vasoconstrictor response in pig coronary artery smooth muscle involves both ETA and ETB -receptors with ETA being predominant. Pretreating the artery with hydrogen peroxide inhibited the subsequent contraction upon ETA or ETB receptor activation. However, the ETB -mediated contraction was significantly (p < 0.05) sensitive to peroxide (IC50 = 0.3 ± 0.08 mM) than the ETA receptor mediated contraction (IC50 = 1 ± 0.3 mM). Pretreating smooth muscle cells cultured from pig coronary artery with 0.3 mM hydrogen peroxide inhibited the endothelin-1 induced increase in [Ca2+ ] i by more than 95%. Thus the exposure to reactive oxygen damaged the ETB receptor mediated contractions preferentially, possibly as a result of a Ca2+ -independent component in ETA receptor mediated contractions. ATP-dependent azide-insensitive oxalate-stimulated Ca2+ -uptake in permeabilized smooth muscle cells cultured from pig coronary artery exhibited the expected kinetic properties of the sarcoplasmic reticulum (SR) Ca 2+ -pump. Under optimum conditions, inositol 1,4,5 trisphosphate (IP 3 ) released up to 65% of 45 Ca2+ -loaded into the SR. Pretreating the cells with hydrogen peroxide or superoxide did not affect the IP3 dependent Ca2+ -release but inhibited the Ca2+ -uptake in the SR. Peroxide was equipotent in inhibiting 45 Ca2+ -loading into IP3 -sensitive and IP 3 -insensitive Ca2+ pools but superoxide inhibited loading only into the IP3 -sensitive pool indicating that the SR Ca 2+ pump in vascular smooth muscle cells is heterogenous. These results indicate that both ETA and ETB receptors are involved in ET-1 mediated contraction in smooth muscle pig coronary artery, with similar Ca2+ utilization pathways but the ETA receptors may also induce contraction in part by a Ca2+ -independent mechanism. The peroxide pretreatment damages the SR Ca2+ pump and this leads to a diminished contraction by endothelin-1, with the exception of the Ca2+ -independent mechanism(s) associated with ET A receptor activation which may be resistant to peroxide. This Ca 2+ -independent mechanism provides a potential therapeutic target for diseases where ETA plays a major role. The second major finding is the heterogeneity of SR Ca2+ pool which can also be used in designing pharmacological agents specific to a distinct component of the SR Ca2+ pool.

abstract: Doctor of Philosophy (PhD)


title: Algorithm for Transient Sediment Deposition and Resuspension in a One-Dimensional Zone Between an Outfall and a Receiving Water

contributor:
James, W.
Civil Engineering

subject:
Civil Engineering
Civil Engineering

abstract:
A mathematical model to predict the bed sediment and suspended sediment load as a function of time and distance along a one-dimensional quasi-steady receiving area is described. The model called TOTSED, uses the modified. Einstein approach for bed load calculations and the Einstein approach for suspended load calculations. The plug flow reactor is used for the inflow load (sediment pollutograph) calculations.

The model was verified and calibrated using data obtained from a sampling program carried out in Chedoke Creek outfall channel in Coote's Paradise in Hamilton during summer 1980. Similar computations were carried out using the HEC-6 program. TOTSED predictions compare favourably with both HEC-6 and the observed data. TOTSED has been modified to be a new block of the SWWM program.

abstract: Master of Engineering (ME)


title: Application of the Theory of Atoms in Molecules

contributor:
W., R. F.
Chemistry

subject: Chemistry Chemistry

abstract:
This thesis applies the theory of atoms in molecules to a series of hydrocarbon molecules. The atoms of theory are those that satisfy the quantum boundary condition. It is shown that regions of real space that obey this quantum boundary condition exist and the quantum mechanics which governs the total system also governs the atomic subsystems. These atoms of theory can be identified as the atoms of chemistry. An important result of this is that the total value of a property is a sum of the atomic contributions. Standard group energies can be defined. Using these facts, the additivity scheme for the homologous series of hydrocarbons, CH₃(CH₂)mCH₃, starting at m=0 is recovered. The standard group energies are used in the prediction of strain energies. Finally it is shown that the Laplacian of the charge distribution is able to recover both the geometry model of Lewis and VSEPR theory as well as chemical reactivity.

Chapter I gives an overview of the basic theory itself while Chapter II examines the charge density for evidence of the atoms of theory. In Chapter III and IV a series of hydrocarbon molecules are investigated using the theory of atoms in molecules. Chapter V uses the Laplacian of the charge density to recover the Lewis and VESPR models and to provide a deeper understanding of the bridgehead bond of propellane molecules.

abstract: Doctor of Philosophy (PhD)


title: Multivariable Control: Design, Robustness, And Nonlinear Inferential Control For Semi-Batch Polymerization Reactors

contributor:
MacGregor, John F.
Chemical Engineering

subject:
Chemical Engineering
Chemical Engineering

abstract:
This thesis presents new results in the research area of multiple input/multiple output(MIMO) controller design for chemical processes. The topics considered in this work are: robustness properties of linear MIMO controller designs; the design of approximate inverses for linear MIMO controllers; disturbance prediction in model predictive controller designs; and the development of a nonlinear inferential feedback control strategy for semi-batch copolymerization processes.

A review of robustness analysis procedures based on the use of norm bounded mismatch regions in the frequency domain is presented. These theories are considered for use in the assessment of the relative robustness trends of different MIMO Internal Model Controller designs. Based on these theories, three approaches to analyzing robustness properties are considered: the use of a condition number and singular value analysis on the approximate model inverse; singular value analysis assuming unstructured norm bounded uncertainty; and new procedure based on disk uncertainties in each element of the transfer function matrix that requires the use of structured singular value theory. The problems of conservatism with each approach as a result of unrealistic uncertainty characterizations is discussed, and new results are provided. The approaches are compared and evaluated with different MIMO Internal model controller designs. Compared to previously proposed procedures for relative robustness assessment, new proposed procedure based on disk uncertainties in each element of the transfer is shown to reduce conservatism in analyzing controller design robustness trends.

A general method for obtaining least squares optimal inverses for multivariable Internal Model Controllers (IMCs) is presented. An analytical solution is arrived at using a well known method for optimally factorizing discrete transfer function matrices. The procedure automatically handles unbalanced, noninvertible, and nonsquare systems, and provides controllers with excellent performance and robustness properties. These IMC designs are compared with some of the more traditional IMC designs where tunable diagonal filters are combined with fixed but usually suboptimal inverses. Robustness properties are investigated in simulated mismatch case studies, and with the robustness assessment procedures described above.

A general procedure is proposed for improving disturbance regulation in MlMO Dynamic Matrix Controllers (DMC). The method makes use of autoregressive, integrated moving average disturbance models to provide disturbance predictions, and requires only a simple modification to the DMC algorithm. The method proposed is far more computationally efficient and simple to apply relative to other procedures proposed. Examples are presented were the proposed modification leads to a substantial improvement in DMC disturbance regulation.

A strategy is proposed for estimating and controlling properties of styrene/butadiene rubber (SBR) latex produced in a semi-batch reactor. The nonlinear control strategy features a nonlinear state estimator, a nonlinear open-loop feedforward compensator, and a linear feedback controller to correct for errors in the feedforward control actions. In arriving at a nonlinear state estimator, three approaches, extended Kalman filtering, extended Kalman filtering with global reiteration, and a nonlinear optimization approach were considered. The second approach was found to be most effective and was therefore adopted. The importance of introducing sufficient meaningful nonstationary states is discussed in order to have biased-free state estimates when nonideal conditions exist. Using the knowledge of modelled chemical reaction mechanisms, open-loop feedforward actions are proposed based on establishing conditions for maintaining fixed instantaneous copolymer properties. These open-loop/feedforward policies establish quasi-steady state conditions on the instantaneous copolymer properties to be controlled. This allows for the application of simple feedback control strategies to correct for errors remaining after the open-loop/feedforward actions. The approaches considered for feedback controller design were conventional paired PI, a decoupling and linearizing mullivariable transfonnation approach, and model-based optimal controller design. The second approach was found to be the most convenient for use in the nonlinear inferential feedback control scheme. The performance of the overall nonlinear inferential feedback design strategy proposed in this work is demonstrated to be robust to model mismatch, disturbances, and state initialization errors. In all cases investigated, copolymer properly control is greatly improved over a fixed operating policy determined off-line. The proposed strategy is simple and effective alternative to computationally intensive on-line optimization procedures, and has the potential for greatly improving product reproducibility and quality control in polymer manufacturing industries.

abstract: Doctor of Philosophy (PhD)


title: Dining in the Dakhleh Oasis, Egypt: Determination of diet using documents and stable isotope analysis

contributor:
Schwarcz, H.P.
Anthropology

subject: Anthropology Anthropology

abstract: This study involves the reconstruction of diet for three cemetery populations (ca. 800 BC to AD 350) from the Dakhleh Oasis, Egypt, using stable carbon and nitrogen isotope analysis in conjunction with documentary and archaeological evidence. Very few isotopic paleodietary studies have been conducted on samples from extremely arid conditions, nor have they had the luxury of including documentary and archaeological evidence of diet. Results indicate a shift in diet from the early cemeteries ('ein Tirghi and Kellis 1 cemeteries) where inhabitants consumed a diet composed mainly of C3 foods, to a diet that included millet (a C4 plant) by the early Roman period (Kellis 2 cemetery). Comparisons within cemetery populations, particularly Kellis 2, reveal sex and age differences in diet. Adult males were found to be enriched in 13 C over females, indicating a heavier reliance on either millet or the flesh of cows and/or goat (which were found to be significantly enriched in 13 C in comparison to the other animals). Infants' δ 13 C and δ15 N values were also found to be significantly elevated in comparison to adults. The enrichment in 13 C suggests that supplementary foods of cow's and/or goat's milk was introduced at a very young age (before 6 months). Comparisons of δ13 C values between archaeological and modern botanical remains suggest that towards the end of the occupation of the Roman period site of Kellis the agricultural fields were becoming increasingly laden with salt. This may have contributed to the ultimate demise and abandonment of this site during the 4th century AD. These findings suggest that by the Roman period the inhabitants of the Oasis had changed their dietary regime through the introduction of millet, reflecting changes in the economic and social structure of greater Egypt during this time period.

abstract: Doctor of Philosophy (PhD)


title: Parallel Implementations of the Kalman Filter for Tracking Applications

contributor:
Haykin, S.
Electrical Engineering

subject:
Electrical and Electronics
Electrical and Electronics

abstract:
The first parallel implementations of the extended covariance Kalman filter (ECKF) and the extended square root covariance filter (ESRCF) for tracking applications are developed in this thesis. The decoupling technique and special properties in the tracking KF are explored to reduce computational requirements and to increase parallelism.

The use of the decoupling technique to the ECKF eliminates the need for a matrix inversion, and results in the time and measurement updates of m decoupled (n/m)-dimensional state esimate error covariance P₀(k)'s instead of 1 coupled n-dimensional covariance matrix P(k), where m denotes the tracking dimension and n denotes the number of state elements.

Similarly, the use of the decoupling technique to the ESRCF separates the time and measurement updates of 1 coupled P½(k) into those of m decoupled P₀½(k)'s.

The updates of m decoupled matrices are found to require less computation than those of 1 coupled matrix, and they may be performed for each axis in parallel.

In the parallel implementation of time and measurement updates of P(k) in the ECKF, the updates of m decoupled P₀(k)'s are found to require approximately m times less number of processing elements and clock cycles than the updates of 1 coupled P(k). Similarly, the parallel implementation of the updates of m decoupled P₀½(k)'s in the ESRCF requires approximately m time less number of processing elements and clock cycles than that for 1 coupled P½(k).

The transformation of the Kalman gain which accounts for the decoupling of P(k) and P½(k) is found easy to implement.

The sparse nature of the measurement matrix and the sparse, band nature of the transition are explored to simplify matrix multiplications.

abstract: Doctor of Philosophy (PhD)


title: Terrestrial input to estuarine bivalves as measured by multiple stable isotopes tracers

contributor:
Schwarcz, Henry P.
risk, Michael J.
Geology

subject: Geology Geology

abstract:
Stable isotope ratios of carbon, nitrogen, hydrogen and oxygen were used here, to trace the extent of terrestrial input to estuarine bivalves (Mytilus edulis) during the summer of 1984 and 1985. Salinity records indicate a stronger river influence in 1985 compared to 1984.

Fatty acids ratios (C24/C16, C24/C14) are intercalibrated with stable isotopes of carbon (δ¹³C) and nitrogen (δ¹⁵N) to characterize the sediments of a Negro Harbour, a small estuary which receives mixed terrestrial input. The relative contribution of terrestrial and organic matter calculated through fatty acid and stable isotope ratios were generally in agreement for sample sites in the upper part of the estuary. However, changes in the relative contribution of peat compared to higher terrestrial plants are more readily noticed using fatty acid ratios than with isotope ratios.

δ¹³C and δ¹⁵N were both compared in the organic matrix (lifetime average diet) and in the flesh (short-time variation) as well as in the stomach content (which were assumed to reflect the diet), the sediments, POC and marine plants. Based on δ¹³13C of the flesh more so than for δ¹⁵N values, it seems that Mytilus edulis take up some of the terrestrial material coming from Clyde river. The uptake was higher in 1985 which agrees with the river influence being stronger during that period of time.

The isotopic fractionation between the organic matrix of M. edulis and the stomach content (assumed to be the immediate diet) average about 4‰ for carbon and 2.0‰ for nitrogen. There seems to be less fractionation between the flesh and the organic matrix using nitrogen isotope compared to carbon isotope ratio. δ¹³C and δ¹⁵N of organic matrices do not change over a period of one year and are therefore useful in evaluating long-term changes in diet of bivalves and regional differences. The organic matrix resemble in certain characteristics, the collagen of bone, which is widely used in paleodiet studies. Thus, the organic matrix could be used in well preserved fossils to learn about the past diet of molluscs.

Stable isotopes of carbon and oxygen of the calcitic shell of M. edulis were also investigated since carbonates are often used to indicates freshwater input in paleoenvironments. In general, shells were close to equilibrium with the surrounding water. But, the results obtained here showed that the use of carbonates to detect past estuarine environment could lead to misinterpretation due to possible biological effects that inhibits calcification (as noted near the head of the estuary).

abstract: Doctor of Philosophy (PhD)


title: Property Tax Distortions as an Explanation of the Flypaper Effect

contributor:
Burbidge, J.B.
Johnson, J.A
Robb, A.L.
Economics / Economic Policy

subject: Economics Economics

abstract:
This study investigates how local government behaviour is altered when property taxes are permitted to distort both the median voter's housing consumption decision and the spatial location of firms. It is demonstrated that optimizing politicians, in the presence of either or both of these property tax distortions, will, contrary to the predictions of standard median voter models, respond asymmetrically to increases in local resources and increases in intergovernmental lump--sum aid. Moreover, the model predicts that property tax distortions will cause the local politicians to allocate more of an increase in aid to public sector expenditure than it would for an equivalent increase in income. That is, the theoretical model offers an explanation of the so-called "flypaper effect", which is contingent upon neither the coercive power of the bureaucracy nor the mistakes of the pivotal voter.

In addition to developing an optimizing model which generates the flypaper effect, the predictions of the model are tested by applying White's (1980) least-squares-covariance-matrix estimator to the per capita expenditure equation derived from the model. Instrumental variable estimation is also utilize to correct for simultaneous equation bias that might result from the property tax distortion variable. The bins is due to the fact that the ax distortion term is a function of the property tax rate which, in turn, is endogenous to the local government's optimization problem.

The key finding of the empirical test is that the property tax distortion variable, as predicted by the model, is both negative and significant. This result is particularly encouraging and provides support for the property tax explanation of the flypaper effect.

abstract: Doctor of Philosophy (PhD)


title: Synthetic, Structural and High Field NMR Spectroscopic Studies of Arene-Chromium Complexes

contributor:
McGlinchey, M.J.
Chemistry

subject: Chemistry Chemistry

abstract:
The reaction of chromium hexacarbonyl with arenes yields organometallic complexes of the type (arene)Cr(CO)₃. Complexation to naturally occurring chiral molecules gives diastereomers which can be differentiated by NMR spectroscopy. Typically, the α- and β-isomers of (methyl ℴ-methylpodocarpate)Cr(CO)₃ have been assigned by using ¹H two-dimensional NMR techniques at 500 MHz.

Tricarbonylchromium complexes of 1,3,5-triphenylbenzene and of hexaphenylbenzene (HPB) have been characterized by NMR spectroscopy. The mono-, bis- and tris-Cr(CO)₃ complexes of C₆H₃Ph₃ exhibit rapid phenyl rotation but (hexaphenylbenzene) Cr(CO)₃ displayed restricted rotation. At -80°C, the chromium-bonded phenyl is effectively orthogonal to the central ring and ΔG# for the fluxional process is = 12.2 kcal molˉ¹ (≈ 51 kJ molˉ¹), a value much lower than those of non-complexed hexa-aryl benzenes bearing ortho or meta substituents.

Sterically crowded chromium complexes of hexaethylbenzene (HEB), (HEB)Cr(CO)₂NO⁺ and (HEB)Cr(CO)(CS)(NO)⁺, exhibit restricted rotation about the arene-chromium bond below -100°C. In the variable-temperature ¹³C NMR spectra of (HEB)Cr(CO)(CS)(NO)⁺ each room temperature singlet observed for the methyl, methylene and arene ring carbons is split into six equally intense resonances at -105°C. This provides the first unequivocal demonstration of slowed tripodal rotation in a chromium complex. Two fluxional processes are observed; the lower energy one (ΔG# ≈ 9.4 kcal molˉ¹ or 39 kJ molˉ¹) involves intereonversion within each distal and within each proximal set. The second process (ΔG# ≈ 11.4 kcal molˉ¹ or 48 kJ molˉ¹) requires exchange between proximal and distal environments.

The protonation of (HEB)M(CO)₃, M = Cr or W, yields species in which the proton directly bonded to the metal atom approaches along the three-fold axis of the molecule. In less sterically crowded systems the HM(CO)₃ fragment is fluxional and adopts a square-based pyramidal geometry.

abstract: Doctor of Philosophy (PhD)


title: An axiological study of Durkheim and Weber

contributor:
Levitt, Cyril
Sociology

subject: Sociology Sociology

abstract: This work examines the contributions of Emile Durkheim and Max Weber to the study of moral phenomena. Durkheim advocated extreme social realism and explained morality as the product of the collective nature of society. However, ample evidence is found to suggest that he conflated the terms 'collective' and 'societal.' Durkheim gave a convincing explanation for the power of the beliefs and ideals of society, its 'collective representations,' but to the extent that his paradigm attempts to become holistic, it fails. Durkheim's errors are described and explained in relation to his own perspective of social realism and to the perspective of methodological individualism. Durkheim's theory readily comes to grip with moral issues faster than alternate theories, but in certain assumptions remains a matter of faith, especially in the belief that society is a collective entity. Methodological individualism remains a better approach for the study of moral phenomena, but is not yet, by itself, the only method. Research in this area can only benefit from an examination of the Durkheimian approach--without of course, accepting the genuine flaws in Durkheim's reasoning. It would appear that the final authority in the sociological investigation of moral phenomena must be methodological individualism. This does not mean that there can be no role for collective concepts derived directly from social realism and its extreme form of social holism. It appears that there are no grounds for formal rapprochement and integration between methodological individualism and collective concepts, at least no possibility was found by an examination of both Durkheim and Weber. Collective concepts may indeed be a useful heuristic device and a means to open up additional questions for investigation, but the final judgement of issues must be made within the premises of methodological individualism.

abstract: Doctor of Philosophy (PhD)


title: Relaxation Phenomena In Thermosets

contributor:
Johari, G.P.
Materials Science

subject:
Materials Science and Engineering
Materials Science and Engineering

abstract:
Two aspects of the electrical and light scattering properties of various epoxide based thermosets have been studied. In the first, the isothermal curing kinetics of the thermosets have been measured at several temperatures by dielectric spectroscopy and Brillouin scattering measurements. During the process of curing, the dc conductivity decreases according to a scaling law, δ₀ ∝ (tg-t)ˣ, or equivalently to a new equation, σ₀ ∝ exp[-B/(t₀-t)], and approaches zero on gelformation. Concomitantly, the time for the dipolar relaxation process becomes progressively longer and the dielectric permittivity becomes dominated by dipolar relaxation processes. The time dependence of the complex permittivity follows the formalism, ϕ(t)=exp-(t/τcure)ˠ with ɣ<0.4. ɣ decreases as the curing temperature is increased and tends towards a limiting value at a high curing temperature. The relaxation time increases on curing and the rate of its increase with respect to curing time first reaches a maximum and then decreases towards zero. This phenomenon is a manifestation of the rates of chemical processes which control the extent of cure. The initially broad Brillouin peak becomes narrow and shifts towards higher frequencies with the curing. The changes in the hypersonic velocity and attenuation during the curing of a thermoset correspond to the changes observed in the dielectric studies.

In the second, both the sub-Tg and main relaxation processes of the thermosets were measured by dielectric spectrometry and their dependence on the curing and ageing were investigated. Amongst the two sub-Tg relaxation processes, the low temperature process is initially prominent and its strength decreases on both curing and ageing of a thermoset. The strength of the high temperature sub-Tg process initially increases, reaches a maximum value and then decreases on further ageing. A concept of accumulated equivalent curing time is introduced and theoretically justified for use in the investigation of the curing of thermosets, and a general method for obtaining the asymmetric distribution of relaxation times parameter from limited relaxation data is developed. For the sub-Tg relaxations, the calculated parameter remains constant during the curing process, but for the main relaxation it monotonically decreases towards a limiting value. The theoretical analysis developed here is generally applicable to phenomena where molecular diffusion allows a chemical reaction to occur, which in turn retards molecular diffusion which slows the chemical reactions, until a material reaches its vitreous state and both the diffusion and chemical reactions cease to occur over ones experimental time scale.

abstract: Doctor of Philosophy (PhD)


title: Hydrogen peroxide production and autocrine proliferation control

contributor:
Singh, G.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: An ovarian carcinoma culture model is the focus of this investigation based on a unique association between an elevated mitochondrial membrane potential and resistance to the chemotherapeutic agent cisplatin. The model consists of the 2008 parental cell line, the C13* subline that has acquired stable resistance to cisplatin and the RH4 revertant line that has regained sensitivity to cisplatin following selection with the anti-mitochondrial agent rhodamine 123. The cumulative data for resistance mechanisms that operate in this model suggest that increased tolerance to damage is a major determinant of the overall cytotoxic response to cisplatin. We have adopted the general hypothesis that mitochondria play a role in the mediation of resistance to cisplatin, and have furthered the investigation of these cells in terms of their energetic and redox balance characteristics. No significant differences exist between 2008, C13* and RH4 cells in terms of glycolytic capacity but when assayed for mitochondrial function both the cisplatin-resistant C13* and the cisplatin-sensitive RH4 cells have a significantly reduced capacity for mitochondrial respiration. This common characteristic indicated that alterations in energy production do not influence resistance, but perhaps other associated mitochondrial activities like reactive oxygen species production could have an impact. Measurement of extracellular hydrogen peroxide (H2 O2 ) production revealed a significant increase in the C13* versus 2008 cell population, which is the result of contributions by multiple intracellular sources including mitochondria and potentially novel flavoproteins. The exact relationship between increased H2 O2 production and cisplatin resistance is not yet defined but one major implication is the evidence for extracellular H2 O2 as a required autocrine growth factor for various cultured cell lines including 2008 and C13* cells. The pro-proliferation role of H2 O2 suggests it could influence the balance of survival versus death effector signals that may have an impact on the threshold of apoptosis initiation in these cells.

abstract: Doctor of Philosophy (PhD)


title: Architectural Features of WCRC - A Data Base Computer

contributor:
Arora, Sudhir K.
Electrical Engineering

abstract:
Several data base machine architectures have been proposed in the past few years. The next generation of these machines must support different data models on the same physical data simultaneously as envisaged in the ANSI/X3/SPARC report or the coexistence model.

This thesis presents the architectural features of one such data base machine called Well Connected Relational Computer (WCRC). The overall architecture and the facilities to the user as well as the DBA have been described. A framework for the conceptual level and detailed design of the internal level are reported. The algorithms for schema conversion and view translation have been developed. The conceptual level language, WCRL is extended to accommodate data definition, data manipulation and storage definition facilities. A high level language, DBAL, is developed for the DBA. Two binary storage structures (Pseudo Canonical Partitions (PCP's - Options I and II) have been reported for storing the data at the internal level. They radically differ from the conventional n-ary relational storage structure. A machine oriented language (WCRML) is developed to directly execute the data base instructions in hardware on the PCP storage structures. The basic hardware organization of the internal level along with special hardware units for some data base functions such as join and sort have been reported. Finally, a performance evaluation of WCRC storage structures has been presented. The results indicate that WCRC requires lesser storage and offers faster query response time when compared to architectures based on n-ary relation storage.

abstract: Master of Engineering (ME)


title: Spatial statistics using quasi-likelihood methods with applications

contributor:
El-Shaarawi, A.H.
Mathematics

subject: Mathematics Mathematics

abstract: Spatial Statistics have been applied to many types of problems in the environmental sciences, mostly dealing with continuously distributed data from Gaussian or near-Gaussian processes. There is a need for methods capable of handling discrete, non-Gaussian data, such as species counts from biological processes. This thesis applies the method of quasi-likelihood from general linear models to the problem of spatial prediction of benthic invertebrate counts. These organisms are important elements of the aquatic food chain and are indicators of pollutant impacts. Predictions of their abundance are needed as clean up targets in areas where remedial actions are being considered. The proposed method is illustrated using an example data set from Great Lakes reference sites. The applicability of the method is first illustrated by re-analysis of examples from the literature. Variogram models are fitted to quasi-likelihood residuals with two alternative distance metrics. The models are compared using cross-validation and predictions are made using the classical estimator of the variogram and distance determined from a Geographic Information System (GIS). Asymptotic normality of quasi-likelihood parameter estimates is shown to hold when spatial dependence is accounted for by an exponential variogram model. A brief simulation study is included that verifies the applicability of asymptotic results to the estimation of model parameters.

abstract: Doctor of Philosophy (PhD)


title: Low Enriched Uranium Fuel Cycle in Heavy Water Reactors

contributor:
Trojan, O. A.
Nuclear Engineering

subject:
Nuclear Engineering
Nuclear Engineering

abstract: Heavy water moderated thermal nuclear fission reactors have a greater inherent neutron economy than light water or graphite moderated reactor designs. Consequently, such units, operating on a variety of fuel cycles, may play an ever-increasing role in meeting future global energy demands. This thesis explores, analytically, the operational advantages and challenges associated with the use of a low enriched uranium (LEU) fuel cycle in advanced reactors based on the CANDU heavy water moderated, pressure tube design concept. The flexibility afforded through the use of LEU fuel is applied to enhance the operational and safety characteristics of reactors utilizing this fuel cycle. An investigation of factors influencing coolant void reactivity is conducted. Design modifications are introduced to reduce the coolant void reactivity, while maintaining the continued capability of high power operation. An enrichment and element radius graded fuel bundle design is developed with a central graphite core, an inner ring of 14 fuel elements, and an outer ring of 21 fuel elements. Fuel and lattice design perturbations are investigated to examine the effect of lattice pitch variations, capability of radioisotope production, the use of burnable poisons, and light water coolant. Xenon override requirements with LEU fuel are addressed. The efficacy of using modified two group (M-2) neutron diffusion theory for LEU fuel management studies is investigated. A modelling strategy is developed for the simulation of reactivity devices and fuel lattice properties using the M-2 methodology with a fixed energy cut-off. Detailed fuel management studies are conducted to examine the operational intricacies of LEU fuelling. Improved checkerboard type fuelling strategies are developed. Finally, the CANDU - Spectral Shift Advanced Thermal Reactor (CANDU-SSATR) is introduced and characterized. This multi-spectrum high burnup advanced reactor design utilizing simplified fuel management strategies holds great promise for the future.

abstract: Doctor of Philosophy (PhD)


title: Valuing health and air quality using stated preference methods

contributor:
Muller, Andrew R.
O`Brien, Bernie
Robb, Leslie A.
Economics / Economic Policy

subject: Economics Economics

abstract: The objectives of this thesis were to examine the use of stated preference methods in the valuation of health and environmental attributes. The first objective was to investigate the current state of research of non-market valuation of health care interventions. The second objective was to examine the potential for using conjoint analysis to value the health and non-health benefits of environmental improvements. A case study was conducted in which conjoint analysis was employed in order to value the attributes of air quality changes in the Regional Municipality of Hamilton-Wentworth. The objectives of the case study were (i) to obtain accurate information about the willingness-to-pay and the health trade-offs of the attributes, and (ii) to gather evidence of the nature and effect of cognitive difficulties and to explore the use of ranking information. In the case study, a total of 1908 surveys were mailed out to households. Four attributes were employed--health effects, black fallout, bad odours, and poor visibility. A fifth attribute--property taxes--was used so that willingness-to-pay could be estimated. Three levels of each alternative were employed: The current situation, one-third better, and one-third worse. Respondents were asked to rank nine choice sets each consisting of four alternatives. Of the 515 surveys were returned, only 115 respondents completely ranked all of the choice sets without choosing a dominated alternative (a dominance violation). Hence, the task was cognitively difficult. Incorporating both first and second ranked choices increased the precision of the results. Conjoint analysis ranked data can provide useful estimates of the trade-offs between attributes of air quality. More research is necessary to evaluate the sources of cognitive difficulties so that policy makers can be more confident with the results. The results from a conjoint analysis study can provide a valuable starting point in any economic evaluation of public goods, particularly health and the environment.

abstract: Doctor of Philosophy (PhD)


title: Rapid Solidification of Intermetallic Compounds

contributor:
Piercy, G.R.
Materials Engineering

abstract:
The intermetallic compound Al₁₃Fe₄ was rapidly solidified at a velocity in excess of 2 to 5m/s by a pulsed laser melting technique. Resolidification after laser melting occurred epitaxially by a stepwise growth process. The phase resulting from this growth process was determined by electron microscopy, to be a faulted slightly disordered variant of the stable compound. The chemical long-range order parameter of this phase was estimated to be 0.6 to 0.7 from the relative intensities of HOLZ spots in an electron diffraction pattern. A model relating order parameter to solidification velocity was developed to explain these results. The measured order parameter of the rapidly solidified Al₁₃Fe₄ was in agreement with the model predictions. A modification of the same model successfully explains the observed velocity at which the intermetallic compound ϒNi₃Al solidified without long-range order. An untested prediction of the general model is that above a critical velocity, estimated to be equal to between 0.5 and 3 times the liquid diffusion coefficient divided by the spacing of close-packed planes in the compound, a compound with long-range order will not form. This model is expected to apply to all types of intermetallic compounds except those in which size factor effects dominate the structure. The results of this work show that rapid solidification experiments on intermetallic compounds can be used to examine the melt-crystal interface kinetics.

Experimental problems associated with pulsed laser melting experiments on intermetallic compounds were also examined in detail. To do this, artifacts from the starting material and from the TEM sample preparation processes were identified and characterized. From this characterization, three important things were learned. Firstly, laser melting experiments on thin films of intermetallic compounds are not equivalent to laser melting experiments on the bulk compound. This was determined by doing laser melting experiments on thin films of Al₁₃Fe₄ on rock salt, which resolidified by nucleation and growth from the melt, in contrast with the bulk compound, which resolidified epitaxially after laser melting. Secondly, the mechanism of laser induced topography developrrent on intermetallic compounds was examined, and found to be a spalling process caused by the thermal contraction on solidification. Thirdly, artifacts from ion thinning were characterized. The most important of these, 10nm grains of redeposited sputtered material on the sample, is difficult to separate from the solidification microstructure without the aid of cross section samples, and thus, may be misinterpreted as nucleation and growth in the melt.

abstract: Doctor of Philosophy (PhD)


title: Isolation and characterization of caveolae from canine airway and intestinal smooth muscle

contributor:
Daniel, Edwin E.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: Calcium (Ca2+ ) for contraction of smooth muscle comes from two sources: release of Ca2+ from an internal site, the sarcoplasmic reticulum (SR), and influx of Ca2+ from the extracellular space across the plasma membrane (PM). We hypothesize that caveolae, flask-shaped invaginations of the PM, are the protected source of Ca2+ . This thesis provides biochemical evidence that supports the hypothesis of caveolae involvement in Ca 2+ handling. Caveolae were isolated from canine tracheal smooth muscle by detergent treatment of PM-derived microsomes. Immunoprecipitation experiments confirmed the presence of calsequestrin and calreticulin in caveolae. Antibodies to caveolin coimmunoprecipitated caveolin with calsequestrin and calreticulin. These experiments also indicated that at least some of the associated calsequestrin and calreticulin are located on the cytoplasmic face of each caveola, since no part of the caveolin protein crosses into the luminal side of each caveola. Immunohistochemistry of fixed tracheal smooth muscle cryosections confirmed that the PM Ca2+ pump, nNOS, and caveolin were all located on the cell periphery, while the SR Ca2+ pump is located deeper in the cell. Based on the results presented here and our previous results of contractility experiments, a model of Ca2+ handling for airway smooth muscle is proposed. This is an extension of the superficial buffer barrier hypothesis first proposed by van Breemen (1986). In our model, caveolae provide the physical basis for the junctional space between the PM and SR. Ca2+ can move into the lumen of the caveolae via the PM Ca2+ pump, and be released from caveolae into the junctional space via L-type Ca 2+ channels. Calsequestrin and calreticulin, located on the cytoplasmic face of caveolae, may act as a physical barrier facilitating the direct refilling of the closely associated SR with Ca2+ . Similarly, nitric oxide, produced by the nNOS located on the caveolae, may inhibit release of Ca 2+ by the SR, thereby enhancing refilling. The Ca2+ in the lumen of the caveolae may be retained by calsequestrin, calreticulin, or another unidentified Ca2+ binding protein located in the caveolae lumen. (Abstract shortened by UMI.)

abstract: Doctor of Philosophy (PhD)


title: Acrylic Water Soluble Polymers

contributor:
Hamielec, A.E.
Chemical Engineering

abstract:
The mechanism of the free radical polymerization of acrylic water soluble monomers has been elucidated. Donor-acceptor interactions between initiator and monomer form a weak charge transfer complex which acts as a secondary source of initiation. This accounts for the unusually high rate dependence on monomer concentration observed for nonionic, anionic and cationic monomers. In polymerizations where the initiator and monomer are segregated, as for example in inverse-microsuspension, monomer enhanced decomposition is absent. Three other reactions dominate: unimolecular chain termination with interfacial emulsifier, heterophase diffusion of primary and oligoradicals and long chain branching with unsaturated carbons on the terminal oleate groups.

A new light scattering procedure has been developed based on the theoretical prediction of the second virial coefficient. The method eliminates greater than fifty percent of the variance in estimation of molecular weight, concomitant with a fivefold reduction in measurement time, and can be applied to any linear polymer, including polyelectrolytes.

abstract: Doctor of Philosophy (PhD)


title: Demons and Domesticity: A History of Women and the London Gas Industry, 1889-1939

contributor:
Rempel, R.A.
History

subject: History History

abstract: When reflecting upon the history of women's employment and commercial advertising, the English gas industry does not usually spring to mind. Historical accounts of the late Victorian years and through the first half of the twentieth century depict the gas industry as being always on the defensive, struggling before the technological triumph of electricity. Such assumptions regarding the teleological march of progress, however, warrant closer examination. In contrast to this accepted view of the gas industry, the most progressive gas managers and engineers developed aggressive marketing techniques, using women as travelling sales personnel and experimenting with mass advertising, long before electricity posed any serious commercial threat. Despite significant interwar electrification, the gas industry expanded its domestic market, supported by a broad consumer base of women in the home cultivated by the industry's home service women. This study focuses on the development of employment opportunities for women in the English gas industry from the 1880s to the 1930s, with a particular emphasis on the city of London. Secondly, it considers the corresponding expansion and diversification of the industry's marketing strategies, and the important role played by women in this process, as both the purveyors and consumers of domestic utility services. Women first entered the gas industry, not as in most businesses as clerical workers, but as professional demonstrators and later, home service women. Nicknamed "lady demons," short for lady demonstrators, these certified cookery teachers instructed ladies, servants and working-class housewives how to use and maintain gas cookers and appliances. As customer service personnel, the gas industry's home service women were highly visible, persuasive advocates for their employers, particularly during the interwar years, as electricity began to present a serious challenge to domestic gas sales. In addition to their public relations role, the home service staff interacted with interwar feminist organizations, engaging in debates over housing standards, school meals and women's health. To date, the historiography of the gas industry in England has addressed what appear to be traditional themes prevalent in business and labour history. These include narratives of technological and corporate progress; debates over market-driven capitalism versus governmental regulated industry; and the successes and failures of late Victorian New Unionism. Collectively, this research locates the English gas industry within the historiography of Victorian industrial development and the consequent struggles between capital and labour. This corpus of scholarship addresses concerns related to the production of gas from coal, but rarely with its consumption. This study offers a contribution to the existing literature by considering the second half of the production/consumption equation, particularly as it pertains to women as the buyers and sellers of public utilities services. (Abstract shortened by UMI.)

abstract: Doctor of Philosophy (PhD)


title: Novel Techniques and Architectures for Adaptive Beamforming

contributor:
Litva, John
Electrical Engineering

abstract:
Recent progress in VLSI technology has created a major impact on digital signal processing, including array signal processing. Proposals have been made for using high throughput processors for digital adaptive beamforming in radar and communications systems applications. In this thesis, novel techniques and architectures for adaptive beamforming will be developed and presented. These are typified by the development of adaptive beamforming algorithms for planar arrays and by a self-calibration algorithm for antenna arrays. The emphasis however will be placed on modern adaptive beamforming techniques in which the adaptation is carried out by means of a triangular systolic array processor performing the QH decomposition.

Adaptive beamforming algorithms for a planar array or two-dimensional (2-D) adaptive beamforming algorithms, which are typified by the 2-D least-mean-squares (LMS) algorithm and 2-D Howells-Applebaum algorithm, are derived and presented. The concept of 2-D eigenbeams will be given to demonstrate the performance of the 2-D adaptive beamforming techniques. As well, the 2-D adaptive beamforming problem will be formulated in terms of the 1-D case with operation taking place along rows and columns of a planar array. The adaptive processor is then implemented by using a manifold of the least-squares triarray processors, which in the limit takes the form of a 3-D systolic array. It will be shown that the structure is capable of performing adaptation along the rows and columns of the 2-D array simultaneously.

One of the major challenges that face workers in array processing is overcoming the degradation in the output of the high performance algorithms due to errors in the calibration of the array. A new self-calibration technique for solving this difficult problem will be derived and presented herein. The algorithm is based on the use of iteration - whereby the calibration coefficients are refined through repetitive imposition of the calibration procedure. Its derivation is based on the eigen-based method and the least-squares norm minimization. It will be shown that the algorithm is capable of automatical estimating the angles-of-arrival (AOA) of the received signals and calibrating the array with a minimum phase and gain errors. Results obtained by using both simulation and measurement data will be given. In the case of the experimental results, the measurement setup is subjected to multipath scenarios.

abstract: Doctor of Philosophy (PhD)


title: Hemingway's Dreams of Places: The Search for the Good Place in the Works of Ernest Hemingway

contributor:
Brasch, J. D.
English

subject:
English Language and Literature
English Language and Literature

abstract: This thesis suggests that before Hemingway is a novelist of character or society, he is a novelist of place. It examines the concern for place in his work and the techniques he uses for the description of place. It further asserts that Green Hills of Africa is a sadly undervalued work in the canon, since it contains Hemingway's major statement at place. Finally, it maintains that Heminway's major concern was in capturing, through his art, a sense of place which could resist the ravages of time and man.

abstract: Doctor of Philosophy (PhD)


title: The presentation of gladiatorial spectacles in the Greek East: Roman culture and Greek identity

contributor:
Slater, W.J.
Classics

subject: Classics Classics

abstract: Once believed by many to offer the historian little of value beyond a horrifying, if titillating, glimpse into the Roman psyche, gladiatorial combat is now appreciated as an important expression of Roman cultural priorities. Gladiatorial combat presented the spectator with examples of the key, martial values at the heart of what it meant to be a Roman: skill with arms in actual combat with an opponent, extreme courage in the face of mortal danger, and the rigid discipline necessary to fight and even die in the quest for victory. Since the Roman sense of cultural identity was based to a high degree on shared values and on participation in the same moral universe, gladiatorial combat, which presented in a spectacular and exemplary way many of these fundamental mores , helped in the construction and maintenance of Roman sense of cultural identity. Throughout the Roman world, the presentation of gladiatorial combats went hand-in-hand with the process of Romanization as different groups of people adopted aspects of Roman culture and a sense of Roman identity. But little seems to have changed in the Greek East as a result of Roman conquest and rule. The main exception to this general rule is the prevalence and popularity of gladiatorial combats. This dissertation considers the significance of this key Roman spectacle in Greek society and its impact on Greek culture. The presentation of Roman gladiatorial combat by Greeks for Greeks in the Greek cities of the East was an attempt to locate Roman culture within a Greek civic and ceremonial context. But the values present in gladiatorial combat are the same values at the heart of traditional Greek culture: the values of the gladiator are essentially those of a heroic champion, who fought in single combat to win glory and fame in victory.

abstract: Doctor of Philosophy (PhD)


title: The Mechanics of Being Alive: Major Themes in the Poetry and Prose of Al Purdy

contributor:
Hyman, R.
English

abstract:
Al Purdy once said that the poet writes about "the mechanics of being alive"¹. "Being alive" is a very large and therefore somewhat vague subject, and Purdy's writing, in keeping with this focus, covers a wide variety of subjects. This thesis is an examination of Purdy's poetry and prose aimed at showing that there are thematic patterns and a unity of vision consistent throughout his wide range of subjects and interests.

Purdy's central point, found in Poems for All the Annettes (1962) to the present, is that to be alive as humans means we must live in full knowledge of the fact of our own inevitable dying. The first chapter of this thesis, entitled "The Season of Man", points out the prevalence of the theme of impermanence in both early and recent poems and in Purdy's one prose work, No Other Country.

Subsequent chapters show that there are other consistent themes in Purdy's writing that grow out of this first and ultimate concern and have to do with how Purdy manages to find peace and enjoyment in being alive, alongside a full acceptance of the processes of time and decay. The chapter "Running" deals with Purdy's belief that such peace is won by active involvement in life, in being truly alive. The next chapter, "This Is a Map of Myself", shows how both Purdy's nationalism and his response to the landscape are shaped by his need to combat the sense of alienation generated by the knowledge of mortality. Purdy's use of the imagination to create a sense of interconnectedness between people of the past, present and future is discussed in "The Long Misty Chain". Again, Purdy's interest in finding continuity in life grows out of his struggle for personal validation and survival. The final chapter, a brief consideration of Purdy's aesthetic purposes and style, shows that he often uses his gift of poetic vision as a means of coming to terms with what he understands to be the realities of life.

abstract: Master of Arts (MA)


title: Self-Perceptions About Activity - Children's Confidence and Enjoyment

contributor:
Streiner, D.L.
Medical Sciences

subject:
Medical Sciences
self-efficacy theory

abstract: This dissertation reports the development of a scale to measure childrens' and adolescents' self-perceptions regarding their involvement in those physical activities typical of youth. Self-efficacy theory is used as a perspective from which to view these perceptions. The test-retest reliability, and both the construct and predictive validity of this scale are investigated and established. The development and testing of a Participation Questionnaire and a Teacher's Evaluation form are also reported herein.

abstract: Doctor of Philosophy (PhD)


title: A Numerical Model of the Surface Energy Balance and Ground Thermal Regime in Organic Permafrost Terrain

contributor:
Rouse, Wayne R.
Geography

subject: Geography Geography

abstract:
Measurements of the surface energy balance and ground thermal regime were carried out near Churchill, Manitoba at two sites in the summers of 1984 and 1985, and a third site in the summer of 1987. The sites represented unforested permafrost locations with a non-transpiring organic surface cover. After examining the microclimatic and ground thermal regimes, the measurements were used to develop a physically-based one-dimensional model capable of emulating the observed regimes. Sensitivity analysis of the model was carried out to determine the relative importance of processes and factors influencing ground temperatures at the study locations, and to assess the validity of using this modelling approach for prediction of changes in the microclimatic or ground thermal regimes.

The data collected in this study represent a complete, comprehensive, and accurate series of measurements of the summer microclimatic regimes at the study locations. On a descriptive basis, the data provides a strong knowledge base of microclimatic processes in this type of terrain. The major significance of the thesis lies in the results of the numerical modelling. Although the general modelling approach is similar to previous models in the literature, the model developed in this study uses a more comprehensive evaporation model which includes a thermal resistance factor acting in the surface layer. Changes in the thermal resistance factor completely reverse the sensitivity of the model to surface moisture changes: with a high thermal resistance the soil cools in response to surface drying, while low thermal resistance values lead to soil warming in response to surface drying. This result is very important in assessing the response of permafrost conditions to local or global climatic change.

In addition, the field data indicate that both surface moisture and surface temperature vary widely over horizontal distances of only a few metres. This result indicates that one-dimensional models may not be capable of treating the evaporation process in a physically-based manner. Evaporation models previously used in the literature may be misleading in their predicted response to climatic change. Further study is required into the nature of the surface evaporative layer, and the validity of one-dimensional evaporation models in non-homogeneous terrain.

abstract: Doctor of Philosophy (PhD)


title: An Analysis of the Population Genetic Structure and Species History of Drosophila Melanogaster and Drosophila Simulans Using Restriction Fragment Length Polymorphisms of Mitochondrial DNA

contributor:
Singh, Rama S.
Biology

subject: Biology mtDNA

abstract:
Animal mitochondrial DNA (mtDNA) has several features that give it great utility in the study of geographic structure of natural populations. Its small size and covalently closed circular conformation make it easy to purify. Strict maternal inheritance and homoplasmy makes the effective copy number of mtDNA as little as 1/4 that of nuclear loci; this renders populational complements of mtDNA less susceptible to the homogenizing effects of gene flow due to migration, and more susceptible to founder effects due to fluctuations in effective population size. The absence of recombination allows for comparatively simple reconstruction of genealogies of mtDNA variants. A comparatively high rate of base substitution assures that most species will have enough mtDNA variants to make population genetic inferences meaningful.

Finally, sequence variants of mtDNA harboured in natural populations are presumed to be selectively neutral (i.e. has no effect on organismal fitness). This means that the distribution of mtDNA variants in populations will be due entirely to the stochastic and deterministic effects of species history, and not to natural selection. As a result, mtDNA can be used to infer species history directly and, after allowing for differences in modes of transmission, to infer the action of natural selection on other genetically determined factors like allozymes. The research of this dissertation was to survey world-wide natural populations of Drosophila melanogaster and its sibling species D. simulans for restriction fragment length polymorphisms of mtDNA. These cosmopolitan species have been widely studied for variation of allozymes and many other genetically determined factors (e.g. chromosomal inversions, morphometric characters).

A total of 144 isofemale lines of D. melanogaster were analyzed from 18 geographic populations. Considerable size variation was observed in this sample. Most size variation occurs in the major non-coding region (A+T-rich region), yielding a total size range of 18.2 kbp to 19.9 kbp. The occurrence of several size variants among all haplotypes indicates that the rate of size mutation is quite high. Further, the frequency distribution of size variants suggests that there is selection against larger sized mtDNA molecules; a replication advantage to smaller sized molecules is a likely explanation. Finally, there is evidence for 'small-scale' size variation (i.e. a total range of 20 bp) in the coding region of mtDNA. However, it could not be determined if the observed mobility variation of the fragments in question was actually due to addition/deletion of DNA or due to conformational effects of particular base substitutions.

Using 10 restriction enzymes, 23 restriction haplotypes were observed in D. melanogaster mtDNA. The phylogeographic distribution of these haplotypes allowed populations to be roughly divided into three longitudinal regions. Euro-African populations showed high intra- and inter-populational diversity and were inferred to be the oldest. Far East populations showed low intra-populational diversity but high inter-populational diversity; these populations similarly have a lengthy, but more complex, history. Western Hemisphere populations have low intra- and inter-populational diversity, and were inferred to be the youngest. A colonization history of this species is proposed. The species history suggested by mtDNA alone is quite similar to one proposed from the collective results of studies on several genetically-influenced traits in D. melanogaster (David and Capy 1988). mtDNA analysis is therefore shown to be a very efficient means by which to study species history. The very different histories of these regions reinforces the notion that the parallel latitudinal clines of allozyme alleles observed in this species (Singh et al 1982) are due to natural selection and are not historical.

A total of 79 isofemale lines of D. simulans from 14 geographic populations (13 continental populations, and the Seychelles Islands) were surveyed. The 10 restriction enzymes revealed a very discontinuous distribution of variation. The continental populations harboured only four haplotypes, while the Seychelles population harboured two haplotypes that were very different from the continental ones. The discontinuous distribution suggests that D. simulans evolved as a series of allopatric ancestral populations, as has been previously suggested. The relative lack of diversity among the continental mtDNAs, coupled with the observation that none of the four continental haplotypes are unique to a single population, strongly suggests that continental populations of D. simulans result from a recent world-wide expansion from one of the ancestral populations, possibly concurrent with the expansion into the western Hemisphere by D. melanogaster. A recent expansion would explain the lower degree of allozyme population structure seen in D. simulans than in D. melanogaster, and is more parsimonious than the alternative explanations of a narrower niche-width or the adoption of a general purpose genotype.

abstract: Doctor of Philosophy (PhD)


title: Artificial Intelligence Approach to Intergration of Feature-Based Modeling and Manufacturing Tasks Planning

contributor:
ElMaraghy, H.A.
Mechanical Engineering

subject: Mechanical Engineering

abstract:
Two important deficiencies have been identified for the integration of CAD and automated process planning. These deficiencies stem from the lack of a uniform representation scheme of pans and products, and an effective communication for CAD and process planning. This thesis presents a new approach and original knowledge regarding the integration and individual aspects of feature-based design, cellular manufacturing planning, inspection planning and assembly sequence planning.

A high-level new language called Feature-based Design Description Language (FDDL) has been proposed and designed with a feature representation scheme. Its syntax, semantics and vocabulary have been defined with consideration given to the user, the engineering terminology, and the computer implementation. The FDDL system consists of a number of lexical analyzers, a parser and three code generators. Once the products or parts modeled by the FDDL, or by a feature-based modeler, are processed using the FDDL system, inputs are created for manufacturing tasks planning systems.

A feature-based modeling and manufacturing tasks planning system has been designed and implemented, and consists of a prototype of a feature-based modeler, the FDDL system, a feature-based cellular manufacturing planning system, a feature-based automated inspection task planner, and a prototype assembly sequence planner. The prototype feature-based modeler is used to model components using features. All expert tolerancing consultant module has been included in the modeler to assist the user. Cellular manufacturing planning deals with group formation and parts assignment to cells. A clustering-based optimization approach has been proposed and implemented for the formation of machine cells and part families. A feature-based assignment system has been developed to integrate the feature-based design and the formed cells. Automata and pattern recognition techniques, in combination with manufacturing knowledge, are used in the system. The feature-based inspection planner has been developed to integrate the feature-based design and a Coordinate Measuring Machine (CMM). Original inspection strategies and knowledge have been developed for CMM, based on the analysis of CMM characteristics, tolerancing theories, features representation, part structure and geometry. A knowledge-based approach has been presented to integrate CAD with the assembly sequence planning. A prototype of such an assembly sequence planner has been developed for generating the assembly sequence for products from the design directly.

abstract: Doctor of Philosophy (PhD)


title: A Study of Fundamentals of a New Metallurgical Reactor

contributor:
Lu, W-K.
Metallurgy

subject: Metallurgy Metallurgy

abstract:
A new metallurgical reactor called the LB furnace is being developed at McMaster University for potential applications in ironmaking, cokemaking and waste oxide recycling.

A bench-scale LB furnace has been built in our laboratory and a series of experiments on ironmaking was carried out with the use of this furnace. The mass balance and thermal efficiency were analyzed for the overall process.

A two-dimensional mathematical model for the turbulent, reacting flows in a confined system has been developed to determine the rates of fluid flow, combustion and heat transfer in the reduction/combustion chamber of this furnace. Measurements of velocity and tracer concentration distributions in two room temperature physical models of the chamber were conducted and were used to assess, the validity of the mathematical model.

The following-conclusions can be drawn: (1) The LB furnace has the potential to efficiently produce sponge iron or liquid hot metal of desired composition.

(2) The mathematical modelling has been shown to be effective in the study of transport phenomena of the turbulent, reacting flows in this metallurgical reactor and has contributed to a better design of the process.

abstract: Doctor of Philosophy (PhD)


title: In Vivo and In Vitro Studies on The Mechanism of Iron-Dependent Lipid Peroxidation in Liver

contributor:
Sweeney, G.D.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
In recent years attention has been drawn to the possible role of iron in a number pathological conditions including ischemia/reperfusion, halogenated aryl hydrocarbon toxicity as well as hereditary and transfusion-dependent iron overload. Although several different mechanisms may be operating in each of these situations, one of the chemical processes thought to be involved is lipid peroxidation (LP). LP is the free radical-mediated, oxidation of polyunsaturated fatty acids which has the potential to cause membrane, protein and nucleic acid damage. Using the non-invasive technique of measuring whole-body ethane and pentane production as an index of in vivo LP in mice, it is shown here that the ferric-NTA complex (Fe³⁺-NTA) is the most potent stimulus of this process yet described. Fe³⁺-NTA was found to be lethal to mice at doses above 5 mg Fe³⁺/kg body weight with a dose of 7.5 mg Fe³⁺/kg, giving rise to a greater than 750-fold rise in the rate of ethane and pentane production 30 min following treatment of mice.

Liver and kidney were identified as likely sites of alkane origination. Radioactive iron (presented as ⁵⁹Fe³⁺-NTA) was concentrated primarily in the liver, and, to a lesser extent, in the kidney. In addition, estimation of products of lipid peroxidation with the 2-thiobarbituric acid (TBA) test confirmed liver and kidney as locations where Fe³⁺-NTA-stimulated LP had occurred in mice treated with the iron complex. Further work, therefore, examined the mechanism by which Fe³⁺-NTA promotes LP in liver tissue.

Isolated rat hepatocytes were found to be susceptible to Fe³⁺-NTA-dependent LP when the process was monitored by measuring the formation of ethane and TBA reacting compounds or emission of low level chemiluminescence. LP and iron association with cells was found to be temperature dependent, both processes being inhibited by incubation at 4°. Subcellular fractionation of rat liver indicated that Fe³⁺-NTA was capable of promoting LP in both mitochondrial and microsomal (primarily, endoplasmic reticulum) only in the presence of reduced pyridine nucleotides (NADH or NADPH). In this, Fe³⁺-NTA was similar to previous reports regarding the ferric-adenosine diphosphate complex (Fe³⁺-ADP).

In depth comparison of the promotion of microsomal LP by Fe³⁺-NTA and Fe³⁺-ADP suggested a common biochemical mechanism, central to which is the reduction of the ferric complex to ferrous. This led to an examination of the initiation of microsomal peroxidation by "free" ferrous ions. In contrast to NADPH/Fe³⁺-NTA-dependent LP which is very rapid, Fe²⁺ addition to microsomal suspensions caused LP only after a variable lag period. This delay could be reduced or abolished by simultaneous addition of Fe³⁺ or by conditions which would accelerate the oxidation of Fe²⁺ to Fe³⁺. In contrast, the delay Iength was increased by antioxidants which acted by hydrogen donation or one electron transfer indicating that the delay period represents time required for the formation of a species capable of initiating microsomal LP. Furthermore, additional Fe²⁺ was also found to increase the delay length. It is proposed that the mechanism behind the delayed initiation of LP is one electron transfer from excess Fe²⁺ to an as yet unidentified initiating species (possibly and Fe²⁺-O₂-Fe³⁺ complex) thus quenching it. Lipid peroxidation is then initiated following consumption of the surplus Fe²⁺. The lack of a delay in NADPH/Fe³⁺-complex dependent LP would be due to the rapid formation of an optimal ratio of Fe²⁺ : Fe³⁺; however, the mechanism of initiation of LP would appear to be similar.

The work presented in this thesis demonstrates the remarkable potential of small amounts of iron, when presented appropriately, to stimulate in vivo lipid peroxidation on a massive scale and with apparently lethal consequences. Furthermore the common mechanism of initiation of LP by iron complexes and the observation that one electron reduction prevents the initial step(s) in LP may prove invaluable in the development of antioxidant drugs for the prevention of iron-dependent cellular damage.

abstract: Doctor of Philosophy (PhD)


title: Knowledge Based Control Systems

contributor:
Sinha, N.K.
Electrical and Computer Engineering

subject:
Electrical and Computer Engineering
Electrical and Computer Engineering

abstract:
There are many different approaches to knowledge based control, in this thesis, three different approaches have been taken for study. These are: -Expert control -Fuzzy logic based control -Qualitative reasoning for control and diagnosis In the first approach, the knowledge based systems acts as a supervisor ro a traditional controller, with the ability to advise an operator about degradation in the performance or if needed tune/change the control algorithm used. This approach is most appropriate when the mathematical model of the systemis known. Several new theoretical insights to the problem of expert control is given in this thesis. An implementation architecture, along with the lessons learned from using such architecture are also discussed.

Alternatively, the knowledge based system may be placed in the control loop; i.e. the control laws may be embedded in rules that are a part of the knowledge based system. Fuzzy logic controllers fall within this category. Fuzzy logic controllers circumvent the problem of designing a controller based on a detail dynamic model by employing the approach of a human operator to an ill-defined system. A step by step procedure for developing such controllers is given in this thesis. This procedure is applied to solve two problems of increasing complexity in the areas of robotic deburring and mobile robotics. Implementation and test results are also given.

The first two knowledge based control techniques have some disadvantages. This is mainly due to the manner in which knowledge is represented, each fact or rule stands on its own as an underivable 'axiom' making it impossible to question the validity or basis of it. Qualitative control system, instead is based on deep knowledge extracted from the understanding of physical interaction between the different components of the plant. This knowledge is used to construct a qualitative model that is used in control operations. In this thesis, an architecture for qualitative control is given and tested on a simple system via simulations. Furthermore, a strategy for expanding qualitative control to provide process diagnostics is also proposed.

abstract: Doctor of Philosophy (PhD)


title: Social Feeding in Burmese Junglefowl (Gallus gallus spadiceus)

contributor:
Galef, B.G.
Psychology

subject:
Psychiatry and Psychology
Psychiatry and Psychology

abstract:
There is reason to believe that birds feeding in flocks enjoy several different types of advantage relative to birds that feed alone. Most relevant to this thesis, flocking can facilitate individual birds' discovery of potential foraging sites. In the present research, both the long-term consequences of social feeding socially were examined in Burmese junglefowl (Gallus gallus spadiceus). The results of experiments presented in Chapter 2 indicated that junglefowl can learn to select either a type of feeding site or a location in which to feed simply by observing feeding companions. Social interaction biased the foraging behaviour of fowl for at least two days after interaction occurred.

In experiments described in Chapter 3, junglefowl used information acquired during the exposure to videotaped companions to orient their own subsequent feeding behaviour. Different aspects of the feeding behaviours of video-taped tutor fowl influenced different aspects of their observers' feeding behaviour. For example, during testing, observer birds' latencies to initiate pecking were reduced by pervious exposure to the sight of conspecifics feeding, while the orientation of observers' pecking was influenced only when observers had both seen and heard feeding companions. The final study, presented in Chapter 4, indicated that observer fowl, even while feeding, were themselves able to learn about foraging sites where videotaped companions fed.

abstract: Doctor of Philosophy (PhD)


title: Hydrogen Embrittlement of A High Strength Low Alloy Pipeline Steel

contributor:
Piercy, G. R.
Metallurgy

subject: Metallurgy Metallurgy

abstract: The effect of hydrogen has been studied on a grade X65 high strength low alloy (HSLA) pipeline steel using a four point bend test. Hydrogen was introduced into single V-notched test samples by a standard BP method. Slow bend tests were conducted on both the base metal and on the heat affected zone (HAZ) of a commercially welded plate. It was found that hydrogen reduced the plastic strain required for crack initiation and increased the rate of crack propagation in three orientations of the base metal and in one orientation of the HAZ. Tests using a higher strain rate, showed that hydrogen still promoted crack initiation but did not affect the rate of crack propagation. Metallographic examination indicated that the orientations of inclusions played an important role in determining the path of crack propagation and delamination.

abstract: Master of Engineering (ME)


title: Effects of Provincial Drug PLan Eligibility on Prescription Drug Utilization among Ontario and British Columbia Seniors

contributor:
Browning, Martin
Economics / Economic Policy

subject: Economics Economics

abstract:
All provincial Ministries of Health in Canada subsidize the prescription drug expenditures of individuals aged 65 and older. This exogenous change in insurance coverage is used to investigate several aspects of the prescription drug utilization of seniors in the provinces of Ontario and British Columbia. First, what is the magnitude of the increase in utilization and insurance program costs once drugs are provided free of charge? The second issue of interest is the incidence of the subsidy. Are any increases in utilization observed concentrated among those with the greatest medical need? Finally, what are the specific effects of the subsidy on physician and patient behavior?

The following conclusions were made. First, the effect of provision of insurance at age 65 is heterogeneous across individuals. Eligibility for insurance was found to increase the number of different drugs taken by Ontario females. In BC, pharmaceuticals use by low income single males in British Columbia was observed to increase. Also, the extension of insurance has made only a minor contribution to growth in seniors' drug utilization, relative to secular trends in utilization by seniors over time. Second, increases in utilization observed among Ontario seniors were concentrated primarily among lower health status individuals. Finally, most of the increases in utilization were among individuals probably already under physician care. The change in drug insurance status did not appear to lead to more physician consultations. The provision of insurance therefore appeared to affect the prescribing patterns of physicians. Given that physicians typically have better knowledge of appropriate drug therapy than patients, this increases the probability that the increased utilization is appropriately prescribed.

abstract: Doctor of Philosophy (PhD)


title: The literary development of John 13--17: A chiastic reading

contributor:
Reinhartz, Adele
Religious Studies

subject: Religion Religion

abstract: While scholars uniformly recognise John 13-17 as a unique literary unit within the Fourth Gospel, these chapters contain various difficulties that distract from their cohesive integrity. Some argue that the problems result from an incomplete or careless editorial redaction, and might even provide evidence of the changing theology of the Johannine community as it moved through successive historical developments (diachronic reading). Others attempt to resolve the inner tensions by positing that the supposed difficulties actually signal changes of mood or spiritual insight, and for that reason belong where they fall (synchronic reading). A third alternative, suggested more frequently in recent years, tries to bring these divergent readings toward some harmony though a different exegetical approach. Reflecting on the influence of the Hebrew Bible on the content and style of the Fourth Gospel, these interpreters see patterns of both micro-chiasm and macro-chiasm in its literary development. They then read John 13-17 as an expression of macro-chiasm. While scholars generally acknowledge the presence of micro-chiasm in biblical literature, there is wide disagreement as to whether macro-chiastic readings are possible. This thesis explores chiasm in the Hebrew Bible and the New Testament on both the micro and macro levels, concluding that it is indeed possible to read passages in each collection as developed macro-chiastically. Further a set of criteria for governing such readings is outlined. These criteria are then applied to the Johannine Farewell discourse. Other chiastic readings of the discourse are reviewed and a new chiastic reading is offered, based on the criteria deduced in the first half of the study. A final section shows how this chiastic reading of John 13-17 allows a new assessment of the points of difficulty, and provides a bridge between the perspectives of synchronic and diachronic interpreters.

abstract: Doctor of Philosophy (PhD)


title: "Mired in attachment": Cultural politics and the poetry of Seamus Heaney and Thomas Kinsella

contributor:
John, Brian
English

abstract: This dissertation examines the connection between Seamus Heaney's and Thomas Kinsella's poetry and the dominant themes of contemporary Irish cultural production and criticism. I begin my study by contextualizing Heaney and Kinsella within the framework of contemporary Irish literary criticism. The discipline is marked by its explicitly political orientation, and in his critical work, The Dual Tradition , Kinsella contributes to the partisan rhetoric that has made Irish studies so inflammatory. In the first chapter, "An Equivocal Response: The Explicitly Political Poetry of Thomas Kinsella and Seamus Heaney," I consider the overtly ideological poetry of both writers within the larger context of contemporary Irish postcolonial criticism. In the next section of my study, "Receding From The Public: Markers of Identity in the Poetry of Seamus Heaney and Thomas Kinsella," I argue that both poets respond to the public demands placed on poetry in Ireland by redressing the narrowly-construed vision of sectarian identity with a more complex and accommodating subjectivity. Both poets turn toward fundamental concerns like a consciousness of place, the linguistic colonization of Ireland, and the vicissitudes of the Irish literary tradition in order to distance themselves from the oppressive demands of contemporary Irish politics. In the final chapter I look at how both poets respond to what they perceive to be a discontinuous Irish literary tradition by intervening actively in that tradition. Specifically, I consider how their employment of bardic poetic modes and traditional themes suggests that both poets feel that this tradition represents a usable past for the modern writer. As well, both poets have translated numerous works from the Irish in order to demonstrate the value of this rich tradition to a contemporary, non-Irish speaking, readership. Finally, in lieu of a formal conclusion, I situate Heaney and Kinsella within the larger context of contemporary Irish poets like Derek Mahon, Paul Muldoon, Medbh McGuckian, John Montague, Nuala Ní Dhomhnaill, and Eavan Boland. In the work of this group of Northern Irish and Republic of Ireland poets, I perceive, in different ways, a similar desire to move contemporary Irish poetry and culture beyond the debilitating politics of sectarian identification. Here I consider a number of political, public, and cultural concerns that have come to the fore in contemporary Irish writing.

abstract: Doctor of Philosophy (PhD)


title: Women and Medical Knowledge in the 1950's: A Study of the Process of Social Construction

contributor:
Tancred-Sheriff, P.
Sociology

subject: Sociology Sociology

abstract:
This study examines how medical knowledge of women is socially informed in historically specific contexts. The case of obstetric and gynecologic knowledge of the 1950s is the focus of this investigation of the social character of medical knowledge.

There is a prevalent notion that error results when medical knowledge is socially influenced. However, in the present work, social influence is seen as involved in the production of all medical knowledge. Thus, the present study offers an alternative conceptualization to dualist models where the medical and the social realms are considered separate entities. In such models, social influences are posited as factors external to medical knowledge. Rather, it is suggested here that the production of medical knowledge of women is a process consistently informed by its social context.

The social production of medical knowledge is indicated by the ways in which professional concerns, social notions of women and gender relations, and the socio-political context were employed as resources in the construction of obstetric and gynecologic knowledge during the 1950s. The technical distinctions made in that knowledge of women's reproductive health arose out of the social resources available to the medical profession in that postwar period. Social concepts of femininity and domesticity are resources displayed in the categorizations of medical normality and pathology generated or accepted by 1950s obstetricians and gynecologists.

The form and content of obstetric and gynecologic knowledge, then, reveal how medical, technical terminology acted as a rhetorical strategy. This strategy allowed decisions to be made about norms and to be presented as neutral and asocial. However, the present research suggests that obstetric and gynecologic knowledge was inherently social in its production and maintenance.

abstract: Doctor of Philosophy (PhD)


title: Questions of travail: Travel, culture, and nature in the poetry of Anne Bradstreet, Elizabeth Bishop, and Amy Clampitt

contributor:
Donaldson, Jeffery
English

abstract:
This study examines the work of three American poets, Anne Bradstreet (1612-1672), Elizabeth Bishop (1911-1979), and Amy Clampitt (1920-1994). Besides the thematic strands of culture and nature, the thesis presents travel, geography, and cartography as underlying metaphors for the processes by which European culture has transplanted itself to this continent. Obviously Anne Bradstreet thought about travel and geography as she set out for the New World in 1630 at the age of eighteen. The English Puritan culture that encodes itself in Bradstreet's poems often reveals how she imagines her own distance from England. Such an engagement also makes Elizabeth Bishop central. Not only does she focus extensively on the themes of travel and geography, but for her such preoccupations stem from a disrupted childhood that made it continually necessary to redefine "home" throughout adult life. Amy Clampitt is also constantly moving about the globe in ways that make the metaphor of travel significant and intriguing. Like Bradstreet and Bishop, Clampitt imagines the landscape as a living organism subject to the actions of humankind, and like them she looks back on a ruptured early personal history.

While I have attempted to take an individualistic approach with each of Bradstreet, Bishop, and Clampitt, I have also continually sought to disclose the important ways in which their oeuvres are related. Thus while the chapters on Bradstreet refer the reader to the extensive critical and historical work already extant concerning both her and her community, those on Bishop similarly allude to her rich association with the work of Charles Darwin, particularly his The Voyage of the Beagle (1836). Clampitt, likewise, looks to Darwin in a no-less important way, although I have also regarded her work on the intersections between nature and culture as akin to that of Annie Dillard. Like Dillard, Clampitt has invited God back into the discourse, taking a step otherwise too problematic for the likes of Bishop. Indeed, the deity so integral to the Puritan interpretation of the environment closely examined in the chapters on Bradstreet cannot be reintroduced without raising serious issues relating to nature.

abstract: Doctor of Philosophy (PhD)


title: Changes in Burst and Spike Propgagtion Associated with Gap Junction Formation in Myometrium at Parturition

contributor:
Garfield, Robert E.
Medical Sciences

subject:
Medicine and Health Sciences
Medicine and Health Sciences

abstract: The factors regulating the uterus in the maintenance of pregnancy and the onset of labor are two important and unresolved problems in uterine physiology. At term, specialized cell-to-cell contacts, gap junctions, appear between the uterine smooth muscle cells. These structures are thought to allow direct passage of ions and small molecules between cells thus their formation between uterine smooth muscle cells at term may promote propagation of electrical activity and development of contractile synchrony in the uterine wall, necessary for expulsions of the fetus(es). The objective of this thesis was to examine the possible functional role of gap junction formation in the myometrium at parturition. The hypothesis that gap junction formation results improved electrical excitation (which give an indirect measure of cell-to-cell electrical coupling_ in the myometrium before (i.e. at preterm) and after (i.e. at delivery) in situ gap junction formation. Some of the tissues used for these experiments were examined by thin section electron microscopy for the presence of gap junctions. Spontaneous burst discharges propagated other the entire recording distance of 15mm in the longitudinal axis of the myometrium at both preterm and at parturition. Burst activity at both times showed some of the characteristics of a system of coupled relaxation oscillators. However, individual spikes within the bursts propagated further with higher velocity in this axis at parturition as compared to at preterm. In the transverse axis of the myometrium, both bursts and individual spikes within bursts propagated over longer distances at parturition than before. Propagation in this axis at parturition appeared to require an intact or undamaged circular muscle layer. Analysis of the propagation of spikes evoked by electrical stimulation confirmed that spike propagation was improved (e.g. higher velocity and long distance spread) in both the longitudinal and transverse axes of the myometrium at parturition. Electron microscopy studies confirmed that gap junctions were present in large numbers between uterine smooth muscle cells during parturition and were absent or present in very small numbers at preterm. Thus, improved propagation of electrical discharges was associated with an increase in gap junction contact between myometrial cells. These results are consistent with the hypothesis that gap junction formation at the term results in improved electrical coupling of the uterine smooth muscle cells.

abstract: Doctor of Philosophy (PhD)


title: Thia-arenes as pollution source tracers in urban air particulate

contributor:
McCarry, B.E.
Chemistry

subject: Chemistry Chemistry

abstract: A method to distinguish coke oven emissions from diesel exhaust emissions in ambient samples has been developed. Sulfur-containing polycyclic aromatic compounds (thia-arenes) and polycyclic aromatic hydrocarbons (PAH) were determined in source samples, standard reference samples and ambient samples using gas chromatography/mass spectrometry. A total of 92 ambient respirable air particulate samples that were collected at four locations upwind and downwind of the steel industries in Hamilton, Ontario in 1995, were analyzed for their total particulate mass, 15 PAH and a number of thia-arene compounds. The steel industries were found to contribute the majority of PAH pollution in Hamilton air particulate above the urban background of approximately 1.5 ng/m3 . Particulate concentrations in Hamilton air indicate several major sources of particulate, including vehicle emissions. Profiles of alkylated dibenzothiophene isomers, 234 amu this-arene isomers and 258 amu thia-arene isomers were examined in Hamilton air particulate, Toronto air particulate, coke oven condensate, Diesel Exhaust Particulate Standard Reference Material (SRM 1650), Urban Dust Standard Reference Material (SRM 1649) and Coal Tar Standard Reference Material (SRM1597). Selected thia-arenes were also examined in a variety of other environmental samples. Principal component analysis (PCA) was used to select suitable thia-arene tracer compounds and examine the relationship between a variety of environmental samples. A thia-arene index was developed using a combination of ratios of selected 234 amu and 258 amu isomers. The suitability of thia-arene tracers for distinguishing coke oven emissions from diesel emissions is demonstrated with Hamilton air particulate and source samples. Ambient samples with particulate bound PAH levels below 1.6 ng/m3 were classified as petrogenic in origin in all cases, while samples with PAH levels above about 3.6 ng/m3 were shown to have significant coke oven impacts. The quality of the thia-arene criteria is discussed in comparison to PAH criteria found in the literature. Four gas chromatography stationary phases were evaluated for the separation of thia-arenes and PAH. Retention index values are reported for 49 PAH and 66 thia-arene compounds. The 50% phenyl-substituted methylpolysiloxane stationary phase provided the best overall separation of thia-arenes and PAH.

abstract: Doctor of Philosophy (PhD)


title: Investigations into the fluorescence of calcitic speleothems

contributor:
Ford, Derek C.
Geography

subject: Geography Geography

abstract: Variations in fluorescence in calcite speleothems may record environmental changes above a cave. It is established that many display annual banding of colour or fluorescence or both, but it is not known what produces the bands or what is the environmental significance of the variability in their fluorescence or thicknesses. Analysis of speleothem feed waters at Marengo Cave, Indiana, found that peak fluorescence values are highest in the spring when soil organics are flushed into the cave or during the early Fall drought. These seasonal characteristics permit annual sequences of fluorescence intensity to be recognized in many speleothems. A comparison of seasonal variability in quantity and types of organic substances in sod and cave waters found that the former display little seasonality in organic concentrations compared to cave waters' peak yields in the spring and fall. Fluorescence studies revealed shorter peak excitation and emission wavelengths in the cave waters, due to differences in concentration and significant changes in the proportional organic assemblages. Precipitation affects the fluorescence in both waters, with the dry fall producing the highest fulvic acid and particulate organic matter yields. Molecular size fractionation determined that larger hydrophobic compounds are preferentially removed from the percolation water and the smaller hydrophilic compounds become the dominant fluorophore in cave drips. Fluorescence of twelve sample speleothems (and extracts) from a wide range of geographical environments gave similar spectra, with broad emission maxima centred around 410-430 nm and two excitation maxima at approximately 255 nm and 330 nm. Trace elements are not responsible for these spectra. Organic acids, particularly fulvic acid, were the dominant fluorophore in the calcite, confirming the Marengo Cave results that show low molecular weight (<1 kD) substances were the dominant organic fraction. Concentration of organics does not relate directly to colour hue or density in the speleothems. Annual bands were found in speleothem fluorescence/phosphorescence signals, with strong similarities between speleothems from the same cave suggesting that the signal is generated by the overlying environment. Correlations between fluorescence/phosphorescence and standard climatic variables are very tentative at present.

abstract: Doctor of Philosophy (PhD)