title: An Evaluation of Voluntary Instruments for Environmental Management: Comparing The Regulation of Toxic Substances in Canada and the United States

contributor:
Sproule-Jones, Mark
Political Science

subject:
Political Science
Political Science

abstract: The use of "voluntary measures" as an alternative policy instrument by government agencies has increased across the world. Such initiatives are based on voluntary commitments by the private sector to improve their environmental performance beyond what the law demands. While there have been many studies which look at the implementation and design of such programs, few provide an empirical comparison of the effectiveness of voluntary measures to other policy instruments. This study provides a comparative analysis of the relative effectiveness of two voluntary measures (the ARET Program in Canada and the 33/50 Program in the United States) in reducing emissions of targeted toxic substances versus reductions under the mandatory regulatory system alone. Data were collected for two study populations, tracking trends in emissions of ten substances from 1988-2000: firms that were participants in the programs and nonparticipating firms (representing the business- s-usual scenario). These ten chemicals were common to the target lists of both programs. The Great Lakes Basin was used as the region of analysis as it is an area of high industrial activity and shared environmental policy between Canada and the United States. Data were also collected for each firm with regards to the following variables in order to evaluate how such firm characteristics affect both participation in and performance of the two programs: industrial sector; firm size; pollution prevention activities; region; compliance records; and participation in other voluntary programs. The study concluded that, for this sample of firms, the ARET program was shown to be more successful in achieving emission reductions than the standard regulatory system alone. Firms participating in the ARET Program reduced their emissions of the ten substances by 44 percent during the tenure of the program, versus a reduction of 18 percent by non-participating firms. For this sample of participating firms, the criticism that a large proportion of reductions claimed under the program actually took place before the start of the program in 1994 is proven false. In contrast, the 33/50 Program in the United States was not as successful. For this sample, participating facilities reduced their emissions of the ten substances by 49 percent during the tenure of the program versus a 60 percent reduction by non-participating firms (representing achievements made under mandatory regulations alone). Regarding firm characteristics: larger firms were both more likely to participate in and perform better in the ARET case study; firms located in Quebec reduced emissions more than those in Ontario; and no correlation was found between firm compliance records and participation in other voluntary programs and greater emission reductions which may indicate that firms joined the two programs as a way to improve their "green image".

abstract: Doctor of Philosophy (PhD)


title: Adaptive Lattice Filtering for Radar Applications

contributor:
Haykin, S.
Electrical Engineering

subject:
Electrical and Electronics
Electrical and Electronics

abstract:
This thesis examines the lattice-structure prediction-error filter, and its application to air-traffic-control radar for the detection of targets (such as aircraft) obscured by clutter (unwanted reflections from the ground or weather systems). The digitally implemented lattice-structure filter adapts to and eliminates the clutter spectrum, producing an output only when a target causes a change in the input signal. Conventional MTI filters do not perform this detection as reliably.

Adaptation to an input signal results from the recursive calculation of the lattice-structure filter's reflection coefficients. Six algorithms for this calculation were examined and compared using simulated radar data. A number of adaptive methods for continuously implementing these algorithms were also analysed. These included the standard gradient and least-squares methods, and two new methods developed in this thesis, the simple gradient and adaptive gradients methods. The harmonic-mean algorithm and the standard and simple gradient methods were selected as most appropriate for this application.

The adaptive learning characteristics (both stationary and non-stationary) of these lattice methods were studied theoretically and experimentally, and quantitative relationships were developed describing their behaviour. The performance of the lattice-structure as a radar clutter filter was examined in terms of improvement factor, receiver-operator-characteristic, and sub-clutter visibility. Both simulated and actual radar data were used. The actual radar data included signals from aircraft, bird flocks, ground clutter, and several types of weather clutter. The performance of the lattice-structure filter with this data was found to be more consistent and consistently better than the conventional MTI filter.

abstract: Doctor of Philosophy (PhD)


title: A Macroeconometric Analysis of the Incidence and Economic Effects of the Corporation Income Tax in Canada

contributor:
Burbidge, J.B.
Economics / Economic Policy

subject: Economics Economics

abstract: [missing page 133]

abstract:
Even though the short-period shifting of the corporate income tax has been the subject of numerous econometric studies, the issue still remains controversial. The question of whether or not corporate profits taxes are shifted is important because of its implications for the distribution of income, the allocation of resources, and economic growth.

A fundamental problem with the existing econometric studies of the short-run shifting of the corporate income tax is the lack of a well defined underlying theory. On one hand, the authors examine the short-run shifting of the corporate income tax while ignoring how the government uses the additional revenues when the tax is raised; that is, they seem to have adopted either a partial-equilibrium or a general-equilibrium full-employment model, when aggregate demand is always fixed at the full-employment level. On the other hand, the inclusion of some Keynesian cyclical variables in their regression equations for the rate of return implies that the authors have implicitly adopted a Keynesian approach. This theoretical inconsistency on the part of empirical investigators of the short-run shifting of the corporate income tax makes their results extremely difficult to interpret.

In this thesis we show that in a conventional Keynesian IS-LM model the incidence and other economic effects of the corporate income tax depend on how the government uses the additional tax revenues when the tax is raised. Furthermore, we demonstrate this point empirically by adapting an existing macroeconometric model of the Canadian economy and conducting several experiments involving the corporate income tax. One of the major conclusions of this thesis is that the shifting of the corporate income tax takes place under expansionary conditions in the economy. In other words, the shifting mechanism operates primarily through changes in aggregate demand and real output, not through changes in prices relative to wages, as is assumed in the conventional approach to the corporate income tax.

abstract: Doctor of Philosophy (PhD)


title: Eigenvalue Sensitivities Applied to Power System Dynamics

contributor:
Sinha, Naresh K.
Electrical and Computer Engineering

subject:
Electrical and Computer Engineering
Electrical and Computer Engineering

abstract:
In the search for an adequate and efficient method for power system dynamic stability analysis, it is illustrated in this thesis that eigenvalues, eigenvectors and their sensitivities with respect to system parameters are very important and useful tools.

The eigenvalue-eigenvector sensitivities are generalized by deriving expressions for the Nth-order sensitivities. These expressions are recursive in nature, hence the calculations of the high-order terms do not involve too much additional computation, but lead to considerable improvements in evaluating the actual changes in the eigenvalues and eigenvectors due to large variations in the system parameters.

A comprehensive and efficient eigenvalue tracking approach has been presented to track a subset of the system eigenvalues over a wide range of parameter variations.

We have achieved an interesting result that the first- and the Nth-order sensitivities of any eigenvalue of the aggregated model with respect to a certain parameter of the original system are identical to the corresponding sensitivities of the same eigenvalue of the original system with respect to that parameter regardless of the choice of the aggregation matrix.

abstract: Doctor of Philosophy (PhD)


title: To Live in Abundance of Life: A Study of Time in Five Canadian Authors

contributor:
Ferns, J.
Hutcheon, L.
English

subject:
English Language and Literature
English Language and Literature

abstract:
The purpose of this dissertation is to present the treatment of time in twentieth-century Canadian literature as a critical approach able to reveal the increasing complexity and sophistication in the literature of this country. By tackling one of the major themes of modern Western literature -- man's relationship with time -- Canadian authors of this century have indicated that their concern is not only with regionalism and nationalism but also with moral and psychological problems common to all mankind.

Fundamental to the critical approach adopted is the idea that twentieth-century literature reflects an interest in the subjective rather than objective aspects of time. The common attempt in prose and poetry to mime a movement away from the objective world into subjective consciousness working in time often blurs traditional genre distinctions to the point of annihilation. Indeed, the works of two poets (Margaret Avison and Al Purdy) and those of three novelists (Frederick Philip Grove, Hubert Aquin and Mordecai Richler) are studied in this dissertation as a single group concerned with internalized, temporal events.

The examination of the treatment of time in the works of Grove, Aquin, Avison, Purdy and Richler as presented in five individual chapters reveals a few common points. Aware of the devastating action of time on man, all five authors, in various degrees, favour an orientation of human experience around those subjective aspects of time which seem to reverse or halt the consciousness of life's progress towards death.

Despite their emphasis on individual ethics, Grove, Aquin, Avison, Purdy and Richler are not oblivious to man's social responsibility, and, therefore, in their works the meaning of human life is also linked to a notion of love and social engagement.

The space about which Grove, Aquin, Avison, Purdy and Richler write is a particular one. But they have been able to distill the particular and the regional in order to extend their themes to a more universal level -- that of the destiny of man facing nature.

abstract: Doctor of Philosophy (PhD)


title: The Special Areas legislation with reference to West Cumberland 1934-1945

contributor:
Rempel, R.A.
History

subject: History History

abstract:
The Special Areas legislation was an attempt to alleviate the social and political problems resulting from regional industrial decline. Though historians are well aware of the legislation, it has not been subject to detailed investigation, and until recently it has concerned mainly economic historians. This emphasis is slightly misplaced, for although the Special Areas Acts were overtly economic, they were introduced, continued and amended for political reasons. This thesis examines the local and national pressures which shaped the Acts and in doing so demonstrates some of the constraints on policy formulation in the 1930's.

The Special Areas Acts were national legislation designed to deal with the particular problems of specific areas. This dissertation focusses on the individual experience of West Cumberland, the least known of the Special Areas. It describes the effect of depression and of the legislation on the society and economy of the area. The legislation stimulated the development of a new local leadership which in itself became a force for change. The study of one locality demonstrates the conflicts inherent in any regional legislation between local desires and official intentions for development.

National rather than regional outcry forced a reluctant Cabinet to agree to the passage of the first Special Areas Act in 1934. The reluctance derived from the Cabinet's adherence to the traditional view that efficient operation of the economy required the free play of market forces. Consequently the first Act was little more than window dressing, offering no real opportunity for industrial development. But the Commissioners and their aides, who were appointed to implement the legislation, were sincere in their efforts to help the Areas. They tried to circumvent the restrictions imposed on them by official policy and formed an internal pressure group pushing the government towards assuming greater responsibility for the conditions of the Areas.

From 1936, the government became increasingly preoccupied with foreign affairs, a focus which has been shared by most subsequent historians. But important changes were occurring in domestic policy. However timid the measures may seem today, the Special Areas legislation of 1936 and 1937, and the Loans Facilities Bill of 1939, all marked an increasing government commitment to stimulating economic recovery. These developments must be seen in the context of a government preparing unwillingly for war. The rearmament programme and the influx of refugees from Europe helped the Areas. They became more attractive industrial centres as awareness of London's vulnerability grew. On the negative side, the escalating cost of rearmament strengthened the government's and the Treasury's determination to rid themselves of legislation that had become increasingly expensive. Their failure to do so, in the face of local and national opposition, displays the limits that can be imposed even on the power of a government with a large majority.

The 1934 Act is unique in the history of regional legislation in that it emphasised the social as well as the economic rehabilitation of the depressed areas. The social measures were palliative, aimed at softening the impact of unemployment and poverty. This field had previously been dominated by private philanthropy. Increasingly under the Special Areas Acts and other legislation passed during the decade, the state assumed wider social responsibilities. The experience of the Special Areas reflects the tensions engendered by this transition.

The evolution of the Special Areas policy followed a pattern of public outcry forcing hesitant government concession. It was the experience of World War II which caused a major change in official attitudes towards intervention in the economy. The experience of full employment brought about by massive government expenditure made the efforts to help the Special Areas in the 1930's look puny indeed. It was partly the memory of the Special Areas which provoked the change to more interventionist policies in Britain after 1945.

abstract: Doctor of Philosophy (PhD)


title: Seed Protein Bodies from Several Members of the Family Umbelliferae

contributor:
Lott, A. J. N.
Biology

subject: Biology Biology

abstract: Protein bodies of the seeds of the family Umbelliferae have not been studied extensively since late in the nineteenth century. Using a variety of recent technology and methodology certain aspects of the protein bodies of carrot (Daucus carota L. cv imperator 408), caraway (Carum carvi L.), anise (Pimpinella anisum L.), dill (Anethum graveolens L.), celery (Apium graveolens L. cv tall utah), fennel (Foeniculum vulgare Mill), parsnip (Pastinaca sativa L. cv hollow crown), parsley (Petroselinum sativum L. c moss curled) and chervil (Anthriscus cerefolium L. cv curled) and wild carrot (Daucus carota L.) were studied. Structure of the protein bodies was determined using light and electron microscopy. Structurally, the protein bodies from all genera studied were similar in that two types of protein bodies were found. One protein body type consisted of a homogeneous proteinaceous matrix and a number of variously sized globoid crystal inclusions. The other protein body type consisted of a homogeneous proteinaceous matrix and either an individual or more commonly an aggregate of calcium-rich crystals, commonly termed a druse crystal. Both protein body types were never found in the same cell. No calcium-rich crystals were found in the embryos. The elemental composition of the various components which compose these protein bodies including globoid crystals, calcium-rich crystals, and the proteinaceous matrix were determined using energy dispersive x-ray analysis. Globoid crystals in the endosperm usually contained either P, K and Mg or P, K, Mg and Ca while in the embryos of carrot and caraway P was always present with a combination of K, Mg and Ca. No elemental distribution pattern was found to explain variations in elemental content of globoid crystals. The calcium-rich crystals contained only calcium and the proteinaceous matrix always contained S and K. Quantitative elemental analyses were carried out and these revealed that most of the Ca was located in the endosperm. During germination and early seedling growth in carrot, few if any calcium-rich crystals were degraded. The chemical composition of the calcium-rich crystal inclusions was determined to be calcium oxalate using a number of methods including x-ray diffraction, infra-red spectrometry, microincineration, staining and solubility studies.

abstract: Master of Science (MS)


title: Essays on Labour Mobility in Western Europe

contributor:
Denton, F.T.
Robb, A.L.
Spencer, B.G.
Economics / Economic Policy

subject: Economics Economics

abstract: Labour migration in Western Europe in the post-World War II period provides substantial evidence of mobility of human resources. Unlike internal migration, which is not inhibited by institutional obstacles, and in contrast to settlement-oriented international migration, intra-European migration has been controlled by the authorities of the labour importing countries and has been of temporary nature, utilized to moderate labour market imbalances. The purpose of this dissertation is to contribute two essays to the literature on intra-European migration. The first essay concerns the impact of labour mobility on labour market adjustments and, more specifically, on wage determination and on the state of excess demand for labour. A model is developed on the hypotheses that, first, wage adjustments, responding to the state of excess demand for labour, are simultaneously determined with quantity adjustments which take the form of migration-induced shifts in the labour supply curve; and, secondly, that wage adjustments are responsive to the characteristics of the structure of the labour market represented by the vacancies-unemployment relationship. Furthermore, it is recognized that mobile labour in Western Europe may be distinguished by EEC and non-EEC citizenship. This distinction is implemented by assuming that mobility of EEC citizens can be explained by the human capital theory of migration, while mobility of non-EEC citizens is determined by a government behavioural function. The model is estimated using West German data. The results confirm that wage adjustments and the state of excess demand for labour are influenced by labour mobility and that the slope of the short-run Phillips curve becomes flatter when the labour market is open. The second essay of the dissertation provides a framework to analyse the determinants of diversification of the foreign labour stock in Western European countries distinguished by country of origin. The model utilizes ideas from the theory of discrimination in labour markets and from the theory of production. The model suggests that discrimination on the basis of nationality and costs associated with labour imports constitute the proximate determinants of the foreign workers mix. The theoretical predictions of the model could be tested empirically should data become available.

abstract: Doctor of Philosophy (PhD)


title: Far-Infrared Absorption of Electron-Hole Drops in Germanium

contributor:
Timusk, T.
Physics

subject: Physics Physics

abstract:
A detailed study is presented of the far-infrared absorption of electron-hole drops in germanium. Experimental observations in the frequency range 1 to 50 meV and at superfluid He temperatures are reported. The lineshape agrees well with Mie's theory of scattering of electromagnetic radiation from spheres with a dielectric constant that includes interband hole transitions and a frequency dependent damping, produced by electron-hole interaction. The electron-hole density is found to be (2.02±0.05)x10¹⁷ cm‾³. The lineshape changes with excitation level. At low excitation surface effects are important, since drops are very small: within a layer of the excitonic Bohr radius the drops have a lower density, and the absorption is damped by collisions with the surface. At high excitation levels, the drops are larger and the absorption lineshape is explained including higher multipole terms in the Mie expansion. Estimates for the drop sizes are presented.

A study of the effect of uniaxial stress on the far-infrared absorption is conducted. Large variations in positions and lineshape are observed for different stress values and direction of polarization of the electric field with respect to the stress direction. The fit to the experimental results to a theory with band structure modified by stress, allows the determination of the electron-hole density as a function of [111] stress, as well as a clearer understanding of the general properties of the fluid under the different conditions.

abstract: Doctor of Philosophy (PhD)


title: Bulk Attenuation Properties of Tropospheric Aerosols as Determined by Surface Measurements

contributor:
Davies, J.A.
Geography

subject: Geography Geography

abstract:
Cloudless sky values of aerosol attenuation coefficient, scattering, absorption, recovery rate, bulk scattering albedo, and absorption to backscatter ratio were evaluated from surface measurements of global, diffuse, and direct beam irradiances for Montreal and Woodbridge (1968-78), Goose (1968-77), Charlottetown and Vancouver (1977-78), Winnipeg (1977), Hamilton (summer, 1977), and Sal (Cape Verde Islands, West Africa, summer, 1974).

The mean value of the coefficient (~0.64) indicates that turbidity of the Saharan dust at Sal is comparable to those of heavily industrialized cities of Europe and Eastern United States but in Canada, the mean values (0.10 - 0.20) for urban areas are less than those for similar cities in the world. The mean value at Goose (~0.05) is typical for the sub-Arctic. For the Canadian locations, maximum values of the coefficient (~ 0.64 for Montreal) occur in summer and the minimum (0.001) in winter but at Sal, maximum values (> 1.0) are reached during the Saharan dust outbreaks that occur once in 4 to 5 days in summer.

Comparison of some meteorological parameters with the values of the coefficient for Montreal and Woodbridge show: a slight inverse relationship with windspeed; maximum values that are generally associated with winds from between southwest and southeast and minimum values associated with winds from between northwest and northeast; a direct positive correlation with dew point temperature and also for relative humidity < 70%; that for visibility more than 10 km there is a strong linear relationship between turbidity and the inverse of visibility.

Mean annual values of the coefficient indicate significant downward trends in cloudless sky turbidity at Montreal and Woodbridge from 1968 to 1978 and at Goose from 1968 to 1977.

The amount of radiation scattered in a forward direction (downward) by aerosol is much larger at Sal (about 42% of global irradiance) than in Canada (6 - 13% of global irradiance). In Canada, aerosol absorption and backscatter are respectively 2-9% and 2-3% of global irradiance compared with 10% absorption and 7% backscatter at Sal. Aerosol recovery rates are least at Montreal. Estimates of bulk scattering albedo for Canadian urban sites (0.6 to 0.8) fall within the range of single scattering albedo values for American locations.

Mean values of the absorption to backscatter ratio indicate that, considering the solar radiation balance, aerosols over Montreal, Woodbridge, Hamilton and Goose could induce warming of the Earth-atmosphere system. Aerosols over Vancouver, Winnipeg, Charlottetown and Sal could induce cooling of the system.

abstract: Doctor of Philosophy (PhD)


title: Two-Photon Sequential Absorption Spectroscopy of Isotopic Species of Iodine and Related Interhalogens

contributor:
King, G.W.
Chemistry

subject: Chemistry Chemistry

abstract:
Two-photon sequential absorption spectroscopy has been used to study the isotopes of the following diatomic molecules: iodine, ¹²⁷I₂ and ¹²⁹I₂; iodine monochloride, I³⁵Cl and I³⁷Cl; and iodine monobromide, I⁷⁹Br and I⁸¹Br. The interhalogens were studied via these methods with no special purification or isotope enrichment. Spectra of each isotope individually could be obtained.

In iodine the B state potential function at large internuclear separation and the B state dissociation limit were examined using a combined isotope, mass-scaled version of Le Roy's long-range potential theory. The absolute vibrational numbering and molecular constants were determined for 4 excited g states in the 5eV region of both isotopes. The E state of iodine was measured in sufficient detail in both isotopes to allow calculation of an RKR potential for this state. The fluorescence lifetimes and the effects of self-quenching and foreign-gas quenching were also measured in these high lying excited states in a preliminary fashion.

In the interhalogens, ICl and IBr, single excited states in the 5eV region were observed. Isotopic data were used to determine the absolute vibrational numbering and thus good molecular constants for these states. The intermediate B' state of IBr was partially measured under high resolution as a necessary prerequisite for the study of the higher lying excited state.

abstract: Doctor of Philosophy (PhD)


title: IMMUNE REGULATORY MECHANISMS OF THE RESPIRATORY MUCOSA

contributor:
Stampfli, Martin
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: Asthma and other allied allergic diseases represent a significant burden to health care and are recognized as endemic in the Western World. While a diverse array of effective pharmacopoeia provides reprieve from symptoms, no preventive or curative therapies are currently available. This is in part due to the paucity of understanding how allergic diseases develop. Recently, remarkable progress has been made in this regard, largely due to the discovery of regulatory mechanisms that control responsiveness to antigen in the airway. Indeed, to understand fully why people develop asthma requires an understanding of both allergic sensitization and tolerance. Work presented in this thesis contributes to our knowledge of inhalation tolerance. Using a classical mouse model of allergic airways inflammation, we show in Chapter 2 that inhalation tolerance is a persistent and active process as it prevents the generation of airway eosinophilia, antigenspecific IgE and airway hyperresponsiveness upon secondary immunogenic challenge, independently of IL-lO or IFN-y. Building on these observations, in Chapter 3 we show in a mucosal model of allergic sensitization that inhalation tolerance cannot be broken with the expression of GM-CSF, a potent growth factor and cytokine that has been associated with asthma and allergy in both human and animal subjects. However, concomitant expression of decorin, a natural inhibitor of TGF-f3, reverses inhalation tolerance, thus implicating TGF-f3 as putatively important in regulating responsiveness in the airway. In Chapter 4, we identify an alternative mode of tolerance. We show that chronic exposure to innocuous antigen in sensitized mice does not lead to chronic inflammation but to abrogated eosinophilia that can, nevertheless, be reversed with the expression of GM-CSF. Collectively, these findings enrich our understanding of tolerance and provide a framework for new discoveries that may, ultimately, lead to novel and powerful therapies for allergic disease.

abstract: Doctor of Philosophy (PhD)


title: Pharmacological Cues, Morphine Tolerance, and Morphine Withdrawal

contributor:
Siegel, Shepard
Psychology

subject: Psychology Psychology

abstract:
Results of many studies have demonstrated an important contribution of Pavlovian conditioning to the phenomena of drug tolerance and withdrawal. Based on the conditioning analysis, cues paired with the drug administration conditionally elicit compensatory responses in anticipation of the subsequent drug-induced physiological disturbance. These conditional compensatory responses mediate tolerance development by counteracting the drug effect when the drug is administered in the presence of the drug predictive cues. Additionally, presentation of drug-predictive cues in the absence of the drug elicits the conditional responses, now unopposed by the drug effect. Such conditional responding, elicited by the usual pre-drug cues in the absence of the usual drug effect, constitutes withdrawal symptoms.

Most research evaluating the role of conditioning in drug effects have examined exteroceptive, environmental cues. Recently, however, there has been interest in the interoceptive, pharmacological cues. That is, within each drug administration, early drug onset cues (DOCs) may become associated with the later, larger drug effect (and mediate tolerance and withdrawal behaviors, much like exteroceptive cues). The present experiments examined the role of DOCs in morphine tolerance and withdrawal in rats. The first series of experiments (Chapter 2) concerned the role of DOCs in tolerance to the analgesic effect of morphine. Research described in Chapter 3 evaluated whether DOC pre-exposure attenuates acquisition of conditional compensatory responses, as would be expected on the basis of a conditioning analysis of tolerance. Research described in chapter 4 evaluated the role of exteroceptive cues and DOCs in the elicitation of withdrawal symptoms, using an acoustic startle measure of withdrawaL Research described in Chapter 5 evaluated DOC-elicited behavioral withdrawal symptoms, using procedures to assess whether such withdrawal behaviors represent an associative or sensitized response. The results of these studies have implications for a range of issues in drug tolerance, withdrawal, and the treatment of addition.

abstract: Doctor of Philosophy (PhD)


title: An Abstract Representation And Analysis of Production Lines With Inter-Stage Storage

contributor:
Szabados, Barna
Electrical Engineering

abstract:
This thesis presents a novel methodology to represent a production system with inter-stage storages and variable cycle times. The 'abstract representation', which employs no approximation and is not based on probability, involves: (1) completely representing a system with stages and storages by elements only, each of which contains one stage and some storages, (2) measuring each element independently by supplying a predefined probing rate of job flow across an element and (3) formulating the instantaneous relationships between the independent measurements and system parameters.

This 'abstract representation' is then illustrated by three different problems. The first problem involves on-line system monitoring which requires locating the origins of production loss in a system in real-time. The 'abstract representation' is used to derive the instantaneous relationships between the causes and effects of system production loss among the elements to address this problem.

After the instantaneous relationships between the causes and effects of production loss are derived, a natural extension of this is to apply these relationships to address the problems concerning system performance improvements. Therefore, this thesis will address the second and third problems which are system production control and storage allocation.

The objectives of production control as defined in (Ryzin et al. 93) are to control the system so that one job will be produced in one unit time and to minimize the inventory in the (infinite) inter-stage storage. In this thesis, an algorithm will be derived to address the problem of production control. This algorithm is based on the instantaneous relationships between the causes and effects of production loss and will be designed to theoretically accommodate systems of any size with arbitrary cycle time behaviours. The storage capacities of the system are finite and can have any value. Therefore, the minimization of inventory being carried in an infinite storage is not pan of the objective of the production control algorithm in this thesis. This production control algorithm will calculate the maximum allowable cycle time for each stage for each cycle, so that if these maximum allowable cycle times are met by the stages, the goal of production control can be achieved. Furthermore, the maximum allowable cycle times calculated by the production control algorithm in this thesis will be bounded below so that the maximum cycle time values should fall within an acceptable range.

The goal of storage allocation in a system is to find the amount of storage space between the stages which yields the maximum system efficiency for a certain type of cycle time distribution while satisfying a set of pre-defined constraints. In this thesis, a preliminary study will be undertaken for this problem with the constraint being that the total available storage space is fixed. This preliminary study tries to show that the approximated long term relationships between the causes and effects of production loss can be helpful in providing insights which help solve the problem of storage allocation.

abstract: Doctor of Philosophy (PhD)


title: Evaluation of Yttrium-Doped SrTiO₃ as a Solid Oxide Fuel Cell Anode

contributor:
Petric, Anthony
Materials Science

subject:
Materials Science and Engineering
Materials Science and Engineering

abstract:
A number of perovskite oxides, typically, heavily doped SrTiO₃ samples, were synthesized and characterized with a view to establishing their potential as anode materials for solid oxide fuel cells (SOFCs). The structure, microstructure, electrical conductivity, reduction-oxidation behavior, phase stability, compatibility with electrolytes, and performance in SOFC operation were assessed.

Ceramic samples were prepared with the formula (Sr₁ᵪRᵪ)(Ti₁_yTy)O₃ (R = rare earth elements, T = transition metals) and with charge balance achieved by A-site deficiency. Electrical conductivities were examined by the do four-probe method and impedance spectroscopy. It was found that yttrium is soluble in SrTiO₃ (SYT) up to 8 mol% and has marked effects on conductivity. Electrical conductivities were observed to increase with increasing donor-doping level, on reduction in low oxygen partial pressures. Electrical conductivity with values as high as 82 S/cm was achieved at 800°C and P(O₂) = 10ˉ¹⁹ atm. Electrical conductivities were reversible upon reduction and oxidation. The thermal expansion coefficient is compatible with electrolyte materials such as yttria-stabilized ZrO₂ and doped LaGaO₃. Cobalt-doped SYT, which showed a relatively high resistance to oxidation, was tested as the anode material in a fuel cell. Yttrium-doped SrTiO₃ meets the requirements for the anode in SOFCs to a substantial degree, and is a promising alternative anode material.

abstract: Doctor of Philosophy (PhD)


title: Low Rate Encoding of Autoregressive Sources

contributor:
Anderson, J.B.
Electrical Engineering

abstract: Various approaches, traditional as well as non-traditional, are utilized to encode Gaussian and Laplacian distributed general autoregressive sources at rates of 1 and 2 bit per source letter. The performance of the traditional DPCM encoder is evaluated. At these low rates, DPCM turn out to be rather ineffective from a data compression point of view. Underlying laws governing the performance loss caused by the quantiser non-linearity in the predictor loop are detected experimentally. It is found that tree searching improves the performance substantially and the gain is a very well behaved function of some well known source statistics. Effect of tree searching on mismatched source predictor is examined: The results indicate that tree searching is not a substitute for a matched predictor. The performance of an intution-based smoothing filter in cascade with the DPCM encoder is evaluated when the predictor is matched as well as when mismatched to the source. Such smoothing is not helpful. Finally, a certain random coding scheme is used to rate 1. The performance of such as information theoretic inspired scheme is compared with the tree searched DPCM. Wherever appropriate, the relevance of results to low rate waveform encoding of speech is stressed.

abstract: Master of Engineering (ME)


title: Characterization of indium phosphide and indium gallium arsenic phosphide grown by helium-plasma-assisted GSMBE

contributor:
Thompson, David A.
Engineering Physics

subject:
Engineering Physics
Engineering Physics

abstract: This thesis involved the characterization of InP and InGaAsP grown by He-plasma-assisted gas source molecular beam epitaxy. Samples were typically grown under standard GSMBE conditions, in terms of growth rate and substrate temperature, except for the presence of a low energy helium plasma generated from an electron-cyclotron resonance source. These materials exhibit increased resistivity and faster optical response times with respect to standard materials grown without the plasma. The unusual properties are believed to be caused by the impact of the plasma particles during growth. Samples were characterized under various doping and anneal conditions using Hall effect measurements, temperature-dependent resistivity studies, positron annihilation spectroscopy, photoluminescence and SIMS analysis. Undoped He-InP was weakly n-type as-grown, with a carrier concentration much lower than that of standard InP, suggesting that electron traps were present. On anneal, the carrier concentration decreased further, implying that donor-like defects had been removed. The sample doped with 3 × 1017 cm-3 Be was also n-type; the Be was found to be compensated by donor-like defects. Positron annihilation measurements indicated the presence of single and divacancy defects, which enlarged upon anneal. The characterization of the quaternary constituted the core of the experimental work. He-InGaAsP exhibited the wane trends as the binary He-InP. The undoped and Si-doped samples exhibited low carrier concentrations, indicating the presence of electron traps. Annealing removed these electron traps. The samples doped with <2 × 1018 cm-3 Be were weakly n-type as-grown, but became p-type on anneal, suggesting the removal of donor-like compensating defects. Samples doped with >2 × 10 18 cm-3 Be were p-type as grown, but the hole concentration was lower than expected. As for the He-InP, positron annihilation spectroscopy indicated the presence of neutral or negatively-charged open volume defects that increased in size on anneal. None of the He-InGaAsP samples exhibited photoluminescence until annealed at temperatures of ∼600°C. To estimate the energy levels and concentrations of the defects responsible for the unusual properties of the quaternary, a Fermi-Dirac model was fitted to the Hall effect data. Two donor-like and two acceptor-like levels were identified.

abstract: Doctor of Philosophy (PhD)


title: Microwave Switching and Attenuation with Superconductors

contributor:
Preston, John S.
Engineering Physics

subject:
Engineering Physics
Engineering Physics

abstract:
The discovery of high temperature superconducting (HTS) materials having a critical temperature above the boiling point of liquid nitrogen has generated a large amount of interest in both the basic and applied scientific communities. Considerable research effort has been expended in developing HTS microwave devices, since thin film, passive, microwave components will likely be the first area to be successfully commercialized.

This thesis describes a new thin film HTS microwave device that can be operated as a switch or as a continuously variable attenuator. It is well suited for low power analog signal control applications and can easily be integrated with other HTS devices. Due to its small size and mass, the device is expected to find application as a receiver protection switch or as an automatic gain control element, both used in satellite communications receivers. The device has a very low insertion loss, and the isolation in the OFF state is continuously variable to 25 dB. With minor modifications, an isolation exceeding 50 dB is readily achievable. A patent application for the device has been filed, with the patent rights assigned to COM DEV.

The device is based on an unusual non-linear response in HTS materials. Under a non-zero DC voltage bias, the current through a superconducting bridge is essentially voltage independent. We have proposed a thermal instability to account for this behaviour. Thermal modelling in conjunction with direct temperature measurements were used to confirm the validity of the model.

We have developed a detailed model explaining the microwave response of the device. The model accurately predicts the microwave attenuation as a function of the applied DC control voltage and fully explains the device operation. A key feature is that the device acts as a pure resistive element at microwave frequencies, with no reactance. The resistance is continuously variable, controlled by the DC bias voltage. This distinguishes it from a PIN diode, since PIN diodes have a capacitive reactance that limits their frequency range.

Measurements made to confirm the microwave model validity resulted in the development of a new cryogenic de-embedding technique. The technique allows accurate microwave measurements to be made on devices at cryogenic temperatures using only room temperature calibration standards. We have also investigated the effect of kinetic inductance on coplanar waveguide transmission lines, and indicate under what conditions kinetic inductance must be considered in transmission line design.

abstract: Doctor of Philosophy (PhD)


title: Deriving real-time monitors from system requirements documentation

contributor:
Parnas, David L.
Electrical and Computer Engineering

abstract: When designing safety- or mission-critical real-time systems, a specification of the required behaviour of the system should be produced and reviewed by domain experts. Also, after the system has been implemented, it should be thoroughly tested to ensure that it behaves correctly. This, however, can be difficult if the requirements are complex or involve strict time constraints. A monitor is a system that observes the behaviour of a target system and reports if that behaviour is consistent with the requirements. Such a monitor can be used as an oracle during testing or as a supervisor during operation. This thesis presents a technique and tool for generating software for such a monitor from a system requirements document. A system requirements documentation technique, based on [102], is presented, in which the required system behaviour is described in terms of the environmental quantities that the system is required to observe and control, which are modelled as the initial conditions and a sequence of events. The required value of all controlled quantities is specified, possibly using modes --equivalence classes of histories--to simplify the presentation. Deviations from the ideal behaviour are described using either tolerance or accuracy functions. The monitor will be affected by the limitations of the devices it uses to observe the environmental quantities, resulting in the potential for false negative or positive reports. The conditions under which these occur are discussed. The generation of monitor software from the requirements documentation for a realistic system is presented. This monitor is used to test an implementation of the system, and is able to detect errors in the behaviour that were not detected by previous testing. For this example the time required for the monitor software to evaluate the behaviour is less than the interval between events.

abstract: Doctor of Philosophy (PhD)


title: Magnetron Sputtered Zn₂SiO₄ and Y₂O₃-SiO₂ Thin Film Phosphors for Cathodoluminescent and Electroluminescent Displays

contributor:
Kitai, A.H.
Materials Engineering

abstract:
The cathodoluminescence of various thin films deposited on (111)Si substrates was systematically studied for the first time. The best dopants for red, green and blue (RGB) phosphor films are Eu, Tb and Ce, respectively. A program was developed for the calculation of chromaticity coordinates from the luminescent spectra. High luminescence can only be achieved by post-annealing thin films above 900°C for yttrium silicates or above 850°C for zinc silicates. The band-gaps of the thin films were measured by UV absorption spectroscopy.

Rare earth (Ce³⁺, Pr³⁺, Nd³⁺, Sm³⁺, Eu³⁺, Gd³⁺, Tb³⁺, E³⁺) doped Y₂SiO₅, Y₂Si₂O₇, Y₄.₆₇(SiO₄)₃O and Mn²⁺ doped Zn₂SiO₄ thin films were prepared by magnetron sputtering. Their compositions were studied by Rutherford backscattering and X-ray diffraction. Sputtering parameters such as magnetic field, pressure, target-substrate distance and substrate temperature were studied. The chromaticity coordinates and brightness of thin film phosphors were compared with their powder counterparts. These films show potential for practical applications.

Electroluminescence was found only in Zn₂SiO₄:Mn²⁺ and Y₂SiO₅:Ce³⁺ thin film phosphors. The devices of ITO/Zn₂SiO₄:Mn²⁺ (or Y₂SiO₅:Ce³⁺)/BaTiO₃/Al and multi-insulated phosphor thin films were prepared and their electroluminescent (EL) response under different voltages, frequencies and pulse widths, and their decay curves and transferred charges were studied. With the same chromaticity coordinates as Sylvania powder CL samples, Zn₂SiO₄:Mn²⁺ (2% mole) thin films are shown to have very good EL performance with a brightness as high as 80 foot lambents (fL) excited by 400 Hz a.c. pulses, with a short decay time of 0.6 ms and with an efficiency of 0.78 lumin/watt.

abstract: Doctor of Philosophy (PhD)


title: Neural network sensor fusion: Creation of a virtual sensor for cloud-base height estimation

contributor:
Haykin, Simon
Electrical Engineering

abstract: Sensor fusion has become a significant area of signal processing research that draws on a variety of tools. Its goals are many, however in this thesis, the creation of a virtual sensor is paramount. In particular, neural networks are used to simulate the output of a LIDAR (LASER. RADAR) that measures cloud-base height. Eye-safe LIDAR is more accurate than the standard tool that would be used for such measurement; the ceilometer. The desire is to make cloud-base height information available at a network of ground-based meteorological stations without actually installing LIDAR sensors. To accomplish this, fifty-seven sensors ranging from multispectral satellite information to standard atmospheric measurements such as temperature and humidity, are fused in what can only be termed as a very complex, nonlinear environment. The result is an accurate prediction of cloud-base height. Thus, a virtual sensor is created. A total of four different learning algorithms were studied; two global and two local. In each case, the very best state-of-the-art learning algorithms have been selected. Local methods investigated are the regularized radial basis function network, and the support vector machine. Global methods include the standard backpropagation with momentum trained multilayer perceptron (used as a benchmark) and the multilayer perceptron trained via the Kalman filter algorithm. While accuracy is the primary concern, computational considerations potentially limit the application of several of the above techniques. Thus, in all cases care was taken to minimize computational cost. For example in the case of the support vector machine, a method of partitioning the problem in order to reduce memory requirements and make the optimization over a large data set feasible was employed and in the Kalman algorithm case, node-decoupling was used to dramatically reduce the number of operations required. Overall, the methods produced somewhat equivalent mean squared errors indicating that the descriptive capacity of the data had been reached. However, the support vector machine was the clear winner in terms of computational complexity. As well, through its ability to determine its own dimensionality it is able to relate information about the physics of the problem back to the user. This thesis, contributes to the literature on three fronts. First, it demonstrates the concept of creating of a virtual sensor via sensor fusion. Second, in the remote-sensing field where focus has typically been on pattern classification tasks, this thesis provides an in-depth look at the use of neural networks for tough regression problems. And lastly, it provides a useful tool for the meteorological community in creating the ability to add large-scale, cloud-field information to predictive models.

abstract: Doctor of Philosophy (PhD)


title: Statistical Process Control of Batch Processes

contributor:
MacGregor, John F.
Chemical Engineering

subject:
Chemical Engineering
Chemical Engineering

abstract:
Multivariate statistical procedures for the analysis and monitoring of batch and semi-batch processes are developed. The only information needed to exploit the procedures is a historical database of past successful batches. Projection methods based on principal component analysis and partial least squares are utilized to compress the information contained in the multivariate trajectory data and final product qualities, by projecting them onto low dimensional spaces. When additional information about the initial conditions and set-up of the batch process is available, multi-block approaches can be used to integrate the additional data into the proposed schemes.

The proposed methodology facilitates the analysis of operational and quality control problems in past batches, and allows for the development of simple multivariate statistical process control charts for on-line monitoring of the progress of new batches. Control limits for the proposed charts are developed using information from the historical reference distribution of past successful batches. The approach is capable of detecting subtle changes in the batch operation, and provides procedures for diagnosing assignable causes for the occurrence of observable upsets. The method's potential in analyzing past batches and tracking the progress of new batch runs, is illustrated through a simulation example and data collected from industrial polymerization reactors.

abstract: Doctor of Philosophy (PhD)


title: Role of the Src Family Tyrosine Kinases in Mammary Tumorigenesis

contributor:
Muller, William J.
Biology

subject: Biology Biology

abstract:
Although previous studies have shown that a large proportion of human breast cancers possess elevated c-Src kinase activity its role in mammary tumorigenesis is not well defined. Polyoma virus middle T antigen is known to activate members of Src family kinases (c-Src and eYes). Indeed, mammary gland specific expression of middle T antigen in transgenic mice is known to result in induction of mammary tumors. To test the role played by c-Src and c-Yes activation in mammary tumorigenesis we interbred transgenic mice expressing the middle T antigen with mice lacking either functional c-Src or c-Yes. Mice expressing middle T antigen in the absence of functional c-Src failed to develop mammary tumors while absence of c-Yes did not have any effect. This observation suggests that activation of c-Src kinase plays an important role in mammary tumorigenesis while c-Yes is dispensable for this process.

Activation of the RTK Neu is known to play an important role in breast cancer. Since c-Src tyrosine kinases appear to play a pivotal role in mammary tumorigenesis, 1 investigated whether the Src family members are involved in Neu mediated signaling and tumorigenesis. In vitro kinase assays revealed that c-Src and c-Yes kinase activities were elevated in Neu induced mammary tumors while Fyn kinase activity was not. The increase in kinase activity correlated with the ability of c-Src and c-Yes to associate with tyrosine phosphorylated Neu in vivo. This in vivo interaction is likely due to the ability of c-Src and c-Yes SH2 domains to directly associate with phosphorylated tyrosine(s) on Neu. Although other members of erbB family also play a role in breast cancer, my results suggest that among the RTKs that are known to activate c-Src (EGFR and Neu), c-Src and c-Yes interact only with Neu and not EGFR. These observations suggest that Src family kinases are involved in Neu mediated signaling and tumorigenesis and also suggest that Neu plays a role in EGF mediated activation of c-Src.

Although both c-Src and c-Yes are activated by Neu and middle T antigen, only c-Src is required for middle T mediated tumorigenesis. Indeed c-Src associates with a novel protein, p89, in transformed epithelial cells while c-Yes does not. Future identification of p89 will enable us to understand the mechanism by which c-Src transforms mammary epithelium.

abstract: Doctor of Philosophy (PhD)


title: Structure/Function Studies of Rat Uncoupling Protein in Yeast Mitochondria

contributor:
Freeman, K.B.
Biochemistry

subject: Biochemistry Biochemistry

abstract:
Uncoupling protein (UCP) is one of a family of mitochondrial transport proteins involved in energy metabolism. It is specific to brown adipose tissue mitochondria where it has the primary function in mammals of non-shivering thermogenesis. Heat production is achieved by uncoupling oxidative phosphorylation. It has been suggested that UCP serves the uncoupling role by providing a regulated pathway for proton re-entry back into the mitochondrial matrix. UCP also transports monovalent anions electrophoretically, such as chloride and alkylsulfonates, but the physiological role of anion transport is not yet known, although models based on UCP-catalyzed anion transport for uncoupling have been put forth. Both proton and anion transport are inhibited by purine nucleoside di- and triphosphates, but only proton transport is activated by fatty acid. The detailed mechanisms of ion transport and their regulation remain unknown.

Our approach to studying UCP independently from all other brown adipose tissue mitochondrial protein components was to functionally express UCP in a novel cellular environment. The initial goal of this project was to establish an expression system in yeast to determine whether UCP was responsible for the nucleotide-sensitive ion permeabilities observed in brown adipose tissue mitochondria. Establishing a functional yeast expression system would also allow structure/function relationships of UCP to be explored using site-directed mutagenesis of the UCP cDNA.

An expression system for UCP in yeast was developed by inserting the rat UCP cDNA into a Saccaromyces cerevisiae/Escherichia coli shuttle vector under transcriptional control or the inducible GAL 1 promoter and transforming yeast strain JB516 (MATa, ura3, adel, leu2, his4, gal⁺) with this construct. High level expression of rat UCP in yeast mitochondria was achieved by altering the region around the start codon in the rat UCP cDNA to one resembling a highly expressed yeast gene. Expression of 70-100 μg UCP/mg mitochondrial protein is reported, a level similar to that found in brown adipose tissue mitochondria of cold adapted rats. Functional assays were developed for UCP in yeast mitochondria to measure fatty acid-activated, GDP-inhibited uncoupling of yeast mitochondria and to measure GDP bound to yeast mitochondria containing UCP. Oleate-activated uncoupling that was reversed by GDP was observed and specific for yeast mitochondria containing UCP. In addition, GDP was found to bind specifically to yeast mitochondria containing UCP with a comparable affinity to that found for brown adipose tissue mitochondria, although the level of binding was lower.

Past chemical modification studies on UCP using cysteine and arginine modifying reagents suggested that these residues had functional significance with respect to ion transport and their regulation. However, the specific location of these residues could not be determined. Photoaffinity labelling with purine nucleotide analogs showed that the third domain of UCP was involved in purine nucleotide binding, but these studies also did not identify functionally important residues. The yeast expression system was used in conjuction with site-directed mutagenesis of the UCP cDNA to identify functionally important residues in UCP.

Initial studies focused on the cysteines of UCP, all seven of which are conserved in UCP in all species studied to date. Each cysteine was changed independently to serine. Yeast mitochondria containing independently each mutant form of UCP showed fatty acid-activated, GDP-inhibited uncoupling. Cysteine 253 was modified further to alanine and phenylalanine to further investigate the role of this residue since cysteine 253 had been covalently labelled with a purine nucleotide analogue. These substitutions were also without effect on UCP function in yeast mitochondria. From the cysteine studies, it appears that none of the seven cysteines in UCP serve a critical role in fatty-acid activated, GDP-inhibited uncoupling. The next study investigated the role of arginine 276 in UCP. This residue was mutated to both glutamine and leucine. Yeast mitochondria containing the mutant proteins showed normal fatty acid-activated uncoupling, but the inhibitory effect of GDP was lost. Arginine 276 was therefore found to be involved in purine nucleotide regulation of UCP, but presently, it is not known if this residue is involved directly in the binding of purine nucleotides or in propogating the response in the protein to bound nucleotide.

abstract: Doctor of Philosophy (PhD)


title: Study of Optically Pumped NH₃ Mid-Infrared Lasers

contributor:
Garside, B.K.
Reid, J.
Physics

subject: Physics Physics

abstract:
The work described in this thesis concerns the investigation of the fundamental mechanism involved in off-resonant low power pumped NH₃ mid-infrared lasers. Our theoretical model shows two different contributions to the mid-infrared gain: a Raman-type term and an inversion term. Even if both gain contributions can be present in a laser medium, one process usually dominates over the other. These two processes are characterized by very different properties with respect to the lasing frequency, the magnitude of the gain and the pump absorption. Strong experimental evidence, based on the measurements of these various characteristics, has demonstrated that the Raman-type two quantum transition was responsible for lasing in the NH₃ lasers investigated.

One consequence of Raman lasing is the possibility of obtaining pumped MIR lasers with very low pumping powers. We report here pulsed threshold powers as low as 20 Watts peak which represents an improvement by a factor of 100 over the lowest MIR threshold previously reported. Furthermore, the main parameter influencing the pump threshold value, the offset between the pump frequency and the NH₃ absorption line center, was varied during our experiment. It is shown that a decrease of this pump offset frequency generally reduces the pump threshold, but a very close pump coincidence produces the opposite effect. Consequently, we have estimated that the optimum pump offset for minimum pump power threshold is ~ 100 MHz, for NH₃ in the 12 µm region (at room temperature).

One important extension of this work concerns the possibility of developing an optically pumped cw MIR laser. The low pump power thresholds and long MIR pulse lengths (~ 500 µsec) observed during this work indicate that cw MIR lasing is feasible.

abstract: Master of Science (MS)


title: Social and Cultural Reproduction Processes: Home-Leaving among Canadian Youths

contributor:
Synge, J.
Sociology

subject: Sociology Sociology

abstract: This thesis extends social and cultural reproduction theory in order to provide a theoretical and empirical analysis of the home leaving behaviour of a national sample of Canadian youths (n=2,033) aged 15 to 24 from the 1987 Canadian Youth Foundation Survey (CYFS). The average age among youths who have left home is found to be 18.4. Of those who do leave home between the ages of 15 and 24, only about 27.3 percent leave home between the ages of 20 and 24. It is argued that the availability of family resources (both material and nonmaterial), as well as gender and regional and economic factors, influence decisions related to this important transition. Bivariate and logistic regression analyses of reasons for staying at home and pathways out of the parental home, and proportional hazards modelling of age at home-leaving, are conducted. A key finding demonstrates the importance of family structure (a form of "social capital") to the timing of home-leaving and the choice of pathways out of the parental home. The implications of financial, human, and cultural capital, as well as sex and region, are also examined. The most striking finding is that, at each age between 15 and 24, youths living in two-parent biological families and in lone-parent families are between five and six times more likely to remain at home than are those exposed to stepfamilies, controlling for all of the other variables. Interestingly, young adults living in both stepparent and lone-parent families are more likely to report leaving home because of conflict in parent-child relationships, and are also more likely to leave the nest in order to achieve independence, rather than to marry or to pursue further education. The findings are discussed in terms of their immediate and long-term impact on youths. Implications for social services and counselling are considered, and an agenda for future research is suggested.

abstract: Doctor of Philosophy (PhD)


title: Estimation of Directions of Arrival of Spatially Dispersed Signals in High Resolution Array Processing

contributor:
Wong, Kon Max
Philosophy

subject: Philosophy Philosophy

abstract:
Array processing deals with methods for processing the output data of an array of sensors located at different positions in space in a wavefield. The purpose of the array processing is to obtain insight into the structure of the waves carrying information and traversing the array. Array processing methods have been extensively studied, and results can be found in the literature on radio astronomy, electrical engineering, acoustics, geophysics and statistics.

Recently a group of methods known as the high resolution array processing methods have been developed. All these methods make the assumption that the signals arriving at the array are generated by point sources in space. However, in many practical situations, this assumption is invalid leading to the break down of the high resolution methods.

This thesis is devoted to the study on high resolution array processing methods of the location parameters of physically dispersed sources that generate the signals. The formulation and the properties of spatially dispersed sources are presented. The geometric structure of the data space is examined which enables the partitioning of signal and noise subspaces from which several methods for source localization are proposed. The performance of these methods are analyzed. Engineering applications of this research topic are discussed.

abstract: Doctor of Philosophy (PhD)


title: Performance Optimization of Hierarchical Memory Systems

contributor:
McCrackin, Daniel
Electrical and Computer Engineering

abstract:
The gap between processor speeds and memory speeds is increasing. The performance of supercomputers and the scalability of multiprocessor systems is very dependent on the memory system speed.

A cache system helps to narrow the processor/memory speed gap, but cannot completely decouple the processor from slow memory.

The optimization of main memory performance and the use of a deep multilevel cache hierarchy are proposed here to bridge the processor/memory latency gap.

A novel design that combines optimized bank interleaving with several main memory (DRAM) timing modes to increase memory performance is presented. Four different protocols based on this design are proposed and investigated.

Enforcing the inclusion property for multi-level caches is proposed. A new design that uses three level caches is preserved and three different models are given.

A design flow graph that makes the design of a multi-level memory system simpler and more flexible is introduced. Selected traces that match real workloads running on a wide range of computers are used to calculate realistic overall system performance.

abstract: Doctor of Philosophy (PhD)


title: Cultural identity in Roman Africa: The 'La Ghorfa' stelae

contributor:
Dunbabin, K.M.D.
Classical Studies

subject: Classics Classics

abstract: The 'La Ghorfa' stelae from Roman Africa offer a unique opportunity to study the social and cultural identity of an unusual cult, one that combined aspects of the Punic, Roman, and indigenous cultures. The context and origins of the votive stelae were not recorded upon excavation, but stylistic and iconographic parallels suggest that they come from a part of central Africa Proconsularis known as the pagus Thuscae (Chapter IV), and that they date between the second half of the first century and the first part of the second century A.C. (Chapter V). The pagus Thuscae was a geographic contact point for various cultures in Antiquity, and the 'La Ghorfa' stelae demonstrate that these cultures each contributed to the language, artistry, and religion of the region's inhabitants. Punic, Roman, and indigenous elements appear in the sculptural and epigraphic zones of the stelae, including in the depictions and names of the dedicants (Chapters II and III). Unlike their Punic and Roman predecessors, the dedicants of these ex-votos did not place much significance upon inscriptions; only about one-quarter of the stelae are inscribed, as preserved. Some dedicants portray themselves in the guise of a togate Roman, although only in one instance does the nomenclature in the inscriptions clearly belong to a Roman citizen. In addition, the inscriptions do not name the god or gods to whom these stelae were dedicated, although the sculptural reliefs show a complex combination of gods. The dedicants and their cult come from a stratum of society not normally attested in the archaeological or written record.

abstract: Doctor of Philosophy (PhD)


title: Neutron and X-ray Diffraction Studies of Magnetic Order in U-based Heavy Fermion Superconductors

contributor:
Gaulin, B.D.
Physics

subject: Physics Physics

abstract:
UPt₃, URu₂Si₂, UNi₂Al₃ and UPd₂Al₃ form a special group among the uranium alloys because they exhibit heavy fermion character, magnetic order and superconductivity. This main interest in the study of this group of compounds resides in the simultaneous occurrence of magnetism and superconductivity at low temperature. Such a state could potentially involve an unconventional superconducting pairing mechanism, different from that contained in standard BCS theory.

In this thesis, the magnetic states of three of these materials (URu₂Si₂, UNi₂Al₃ and UPd₂AI₃) is investigated with neutron and the relatively new resonant magnetic X-ray scattering techniques. The work presented here on URu₂Si₂ follows an earlier effort that demonstrated the applicability of the resonant X-ray technique to this weak magnetic system. Access to reciprocal space was extended in order to confirm the multipolar form of the resonant X-ray cross-section and to explore the limits of the technique compared to neutron scattering. The situation with the newly discovered UNi₂Al₃ and UPd₂Al₃ was different since their magnetic structure and phases needed first to be established. This task was achieved using two magnetic probes (neutron and X-ray scattering). Several magnetic order parameters in the normal and in the superconducting phase were also measured. The incommensurate magnetic order found in UNi₂Al₃ by neutron scattering constitutes the first observation of long range order in this compound. Other measurements on this compound provided some clues about the evolution of the magnetic structure in high magnetic fields.

abstract: Doctor of Philosophy (PhD)


title: Uniform Modules Over Serial Rings

contributor:
Müller, Bruno J.
Mathematics

subject: Mathematics Mathematics

abstract: The main result of this thesis is a completely different proof via localization, of the following theorem due to Bruno J. Müller and Surjeet Singh: For any P-tame uniform module M over a serial ring, and the intersection T of the clique of P, the annihilator annM(ΩTⁿ) is uniserial.

abstract: Doctor of Philosophy (PhD)


title: Glycopeptide Antibiotic Biosynthesis and Resistance in Streptomyces toyocaensis NRRL 15009

contributor:
Wright, G.D.
Biochemistry

subject: Biochemistry Biochemistry

abstract: Genetic and biochemical studies were conducted on S. toyocaensis NRRL 15009, a gram-positive sporulating filamentous bacterium, and producer of the glycopeptide antibiotic A47934. This compound is structurally similar to the clinically important antibiotic vancomycin, and the recent spread of vancomycin-resistant enterococci (VRE) in North American hospitals has driven the need for new glycopeptides with enhanced activities. Studies were aimed at developing an understanding of the mechanism of A47934 biosynthesis in S. toyocaensis NRRL 15009, as well as the mechanism of resistance employed by this organism. Two cosmid clones, containing a partial A47934 biosynthesis gene cluster on a total of 65 kilobases of S. toyocaensis NRRL 15009 chromosomal DNA, were isolated for study. Preliminary sequencing indicates the presence of several genes predicted in glycopeptide assembly, such as peptide synthetases and glycosyltransferases. Furthermore, using a oligonucleotide probe designed to identify D-alanine-D-alanine ligases, an 8.1 kilobase chromosomal fragment was isolated from S. toyocaensis NRRL 15009 and found to contain genes very similar to VRE vanH, vanA and vanX. Phylogenetic analysis of the predicted products of these genes showed them to be more similar to the VRE enzymes than any other in each enzyme class. These genes were also found in the vancomycin producer A. orientalis C329.2 and several other glycopeptide antibiotic producing organisms. Not only does this imply that these organisms employ a mechanism of resistance similar to clinical VRE, it also suggests that these organisms may have been the source of the VRE genes. The enzymes VanHst and DdlN were studied in some detail and found to have biochemical properties similar to their corresponding VRE enzymes VanH and VanA, respectively. Given that the latter group of enzymes has physical properties that have impeded detailed analysis of enzyme mechanism, these new enzymes could find use as model systems in drug development programs.

abstract: Doctor of Philosophy (PhD)


title: The Impact of Return Migration and the Determinants of Lifetime Migration in Low Income Countries

contributor:
Jones, Stephen R.G.
Browning, Martin
Feeny, David H.
Economics / Economic Policy

subject: Economics Economics

abstract: To study the impact of return migration on the urban labour market, we extend the basic monitoring model of efficiency wages to include two urban sectors (formal and informal) and a rural sector, and a labour force composed of permanent (or resident) and temporary (or migrant) workers. The proposed model provides a micro-economic foundation for a rural-urban wage gap as well as an intra-urban formal-informal sectoral wage structure. Unlike previous models, our explanation is based on imperfect information on the part of the employer instead of the employee. The proposed model appears to conform closely with stylized facts as discussed in the first chapter. The difference in expected tenure between resident and migrant workers provides a rationale for discrimination by formal sector employers in favour of resident workers, who then have an incentive to engage in signalling, usually by choosing unemployment over informal employment. In this way, the model suggests a non-human-capital based explanation for the incidence of luxury unemployment and predicts that migrants tend to be less likely to endure periods of unemployment. Under certain specified conditions, informal sector wages may be higher than formal sector wages, and informal sector wages may be negative. Using the 1988 Malaysian Family Life Survey (MFLS-2), we provide a description of the migration process in Peninsular Malaysia. The data reveal that three quarters of the moves are other than the standard rural-urban move, and that return migration is widespread, particularly for rural workers. Using cross tabulations, we find that geography and ethnicity variables and the level of education are important determinants of migration patterns. We also find the presence of life cycle effects with a common starting age of between eighteen and twenty. To study the determinants of lifetime migration in a multivariate context, we estimate double hurdle event count models using MFLS-2. Double hurdle models distinguish between factors which affect the probability of migration from factors which affect the number of migrations chosen over a lifetime. Specification testing and in-sample forecasting confirm that double hurdle models perform significantly better than the standard Poisson and Negative Binomial models. The availability of information about different facets of the individual's background allows us to control for factors overlooked in most studies. Specifically, we are able to disentangle the effects of parent's and own education and we find that both effects induce both higher participation rates and a greater number of moves. Studies which do not control for parent's education levels would then be likely to overestimate the effect of own education. We also find support for the effects of location specific capital, particularly in rural areas.

abstract: Doctor of Philosophy (PhD)


title: Extinction to Double Stimutaneous Stimulation and Hemispace Lateralization

contributor:
Carr, D.H.
der, H.I.J. Van
Woodward, C.A.
Medical Sciences

subject:
Medicine and Health Sciences
Neurosciences
Medicine and Health Sciences

abstract: Extinction to Double Simultaneous Stimulation (EDSS) is a perceptual disorder which occurs with varying frequency following lateralized brain lesions, predominantly in the rifht parietal lobe. Correlated with impaired functional recovery of hemiplegic patients, the phenomenon is characterized by faulty or non-recognition of stimuli on the side of opposite to that of the damaged cerebral hemisphere where these stimuli are presented simultaneously with stimuli on the ipsilesional side. Yet the phenomenon cannot be explained by a simple sensory deficiency since a patient who manifests the syndrome correctly identifies the same stimuli on unilateral presentation. EDSS is considered a (milder) sanifestation of the 'neglect' syndrome, that is, the tendency to neglect the contralesional half of the body and space following brain damage. Although known for a full century, the psychoshysiologic mechanisms underlying the syndromes of EDSS and 'neglect' are still poorly understood and many hypotheses remain speculative. Investigation of an underlying mechanism seems essential for the development of treatment strategies aimed at ameliorating the syndrome and thereby conceivably enhancing the rehabilitation potential of this patient group. Although the unilateral neglect of stimuli may involve different sensory modalities, the present study focuses on somatosensory stimuli. The purpose of the present study was two-fold: first, to test two prevailing theories which account for the syndrome of EDSS in hemiplegic patients, and to distinguish between the respective hypotheses; second, to investigate hemispheric asymmetries in the perception of somatosensory stimuli prior to brain injury as a possible basis for the development of unilateral hemineglect after brain lesions. The postulated mechanisms underlying EDSS, stimulus properties and the hemispace in which the stimuli occur, were therefore tested in both a clinical as well as a neurologically intact population. The research questions were addressed in two parts of the study: in study A, electrical stimuli at perception threshold, systematically varied with respect to duration and the hemispace in which they were delivered, were presented to 68 subjects free of neurological disease (34 males, 34 females). The subjects; report of perceived stimuli was recorded and errors of detection were analyzed. In study B, a similar procedure was performed on 19 hemiplegic patients manifesting EDSS. The results indication that both sensory characteristics and attentional factors influence perception. The findings of study A suggest that: 1. The hemispace in which stimuli are presented play a significant role in their perception. 2. A left hemispace advantage appears to be pre-eminent in females. 3. The right hemisphere may be a better 'watchkeeper' for stimuli directed to the left hemisphere that the left hemisphere is for stimuli directed to the right hemisphere. In hemiplegic patients (study B), neither of the two tested theories could account by itself, under the experimental conditions of the present study, for the syndrome of 'extinction'. Based on the present findings, EDSS is viewed as a deficiency in neurointegrative functioning altering the physiological processing of stimuli.

abstract: Doctor of Philosophy (PhD)


title: Growth and Adhesion as Regulators of Cancer

contributor:
Orr, William F.
Singh, Gurmit
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
Cancer cell metastasis to bone is a frequent occurrence with many common-human malignancies, including carcinomas of the prostate and breast. Bone metastasis may be promoted by the phenotypic responses of cancer cells to factors which are present within the bone microenvironment. This thesis describes in vivo and in vitro efforts to test the hypothesis that bone matrix proteins promote the growth and adhesiveness of metastatic cells. An animal model was developed to examine the growth properties of rat mammary cancer cells (Walker 256, W256) in metastatic target organs (Chapter 1). Rats were injected intramuscularly with W256 celIs, which formed spontaneous metastases in the skeleton, liver, lungs, and kidneys within 7-10 days. Skeletal metastasis was associated with a progressive loss of trabecular bone. Within the skeleton, W256 cells which were immediately adjacent to trabecular bone had a 30% greater growth rate than did W256 cells located >50 μm from bone surfaces (p<0.05). These data established the first animal model of spontaneous bone metastasis, and provided preliminary evidence that bone matrix is a possible mitogen for metastatic cancer cells in vivo.

The mitogenic activity of bone matrix may be enhanced by osteoclastic bone resorption (1). To test this hypothesis, bone resorption was stimulated by injecting rats with Leydig tumor cells (Chapter 2). Leydig tumor burden was associated with decreased trabecular bone volume, fewer osteoblasts, and more osteoclasts. Leydig tumor burden was associated with a 56% increase in the growth rate of W256 cells in the skeleton (p<0.05), while W256 cell growth rate in the liver, lungs, and kidneys were not affected. The selective growth promotion of W256 cells in bone suggests the existence of a mitogen for W256 cells which is released from bone matrix during resorption.

Previous in vitro data suggest that this putative bone-derived mitogen may be transforming growth factor β (TGF-β) (1), a factor which can stimulate oncogene expression. Media conditioned by resorbing fetal rat calvarial bones induced a rapid increase in W256 cell expression of c-myc oncogene mRNA and of nuclear c-myc protein (Chapter 3). Purified TGF-β also stimulated c-myc mRNA expression, suggesting that the mitogenic stimulation of W256 cells by bone-derived conditioned media may involve a signaling pathway which is also utilized during TGF-β-induced growth stimulation.

Bone resorption may be a sufficient but unnecessary growth stimulus for metastatic cells in vivo. To test this hypothesis, bone resorption in rats was inhibited in vivo with the bisphosphonate APD prior to their inoculation with W256 cells (Chapter 4). APD blocked the pathologic bone resorption normally associated with W256 tumor burden. However, the skeletal tumor burden in APD-treated rats was 2.6-fold greater than in untreated rats. Tumor burden in other organs was unaffected by APD. W256 cells in the skeletons of APD-treated rats had a 55% greater growth rate than did W256 cells in the skeletons of controls. W256 cells located adjacent to trabecular bone had greater growth rates than did W256 cells>50 μm from bone, irrespective of APD treatment (p<0.05). These data suggest that bone matrix can exert a mitogenic influence on cancer cells without undergoing resorption.

Bone-derived factors are also capable of promoting adhesion (2), and the adhesion of metastatic cells to bone matrix could promote their skeletal localization. An in vitro model of bone matrix was developed to identify potential ligands which could support the adhesion of metastatic cells (Chapters 5 and 6). The extracellular matrix deposited by human U2OS osteosarcoma cells supported the rapid adhesion of human PC-3 prostatic carcinoma cells. Antibodies directed against the integrin-type collagen receptor α2β1 inhibited PC-3 cell adhesion to U2OS matrix and to purified type I collagen, as did a collagen-derived peptide sequence (DGEA) which inhibits α2β1 function. TGF-β treatment caused a selective increase in α2β1 integrin expression, which was effected by increased rates of de novo synthesis of both α2 and β1 integrin subunits. The induction of α2β1 was associated with similar increases in the adhesion of PC-3 cells to U2OS matrix and to purified type I collagen. These data suggest that type I collagen may represent an important bone-derived adhesive ligand for metastatic cells. The abundant expression of type I collagen and of TGF-β in bone may promote bone metastasis by promoting the adhesion of metastatic cancer cells to bone matrix.

abstract: Doctor of Philosophy (PhD)


title: Tumour gene therapy using adenoviral vectors expressing tumour necrosis factor alpha

contributor:
Graham, Frank L.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: The general focus of my project was the production of recombinant adenovirus vectors for use in inmmunotherapy of cancer. The basic strategy involved the infection of tumour cells with Ad-vectors expressing cytokines, inducing a local anti-tumour response. The cytokine of interest for my project was tumour necrosis factor alpha (TNFα), which I used for treatment of a murine transgenic model of breast cancer. TNFα is a pluripotent cytokine with a wide variety of physiological functions including antitumour activity. TNFα was originally discovered through the anticancer activity of sera of mice treated with endotoxin (Carswell et al., 1975). There are two known cell surface receptors for TNFα termed p55 and p75. Both receptors signal a variety of functions and some redundancy exists between them. However the p55 TNF receptor is the major activator of cytotoxicity and cytokine secretion, while the p75 TNF receptor is primarily responsible for proinflammatory and lymphoproliferative signals. Perhaps the major limiting factor affecting the use of TNFα in tumour therapy is its systemic toxicity, through the induction of septic shock and cachexia (Tracey, 1995; Tracey et al., 1986). We have been investigating techniques which would reduce the systemic side effects of TNFα, while retaining its antitumour activity. We found that local expression of TNFα from within a tumour (transduced cells) alone is not enough to eliminate its lethal side effects, therefore two other approaches are being investigated in an attempt to deal with systemic toxicity induced by TNFα. The first was the construction of an Ad vector expressing a membrane bound mutant of murine TNFα (see chapter III). The second approach involved specific targeting of the two cell surface receptors of TNFα. To accomplish this, we used Ad vectors expressing human TNFα, and a novel p75 TNF receptor specific mutant of murine TNFα for use in tumour immunotherapy (See chapters IV and V). It was found that restricting TNFα to the membrane produced a marked reduction in lethality while retaining near normal antitumour activity. Targeting the p55 TNF receptor proved to be ineffective, while targeting the p75 TNF receptor drastically reduced the lethality of the cytokine while retaining some antitumour activity. However the overall efficacy of this therapeutic technique was poor, as only a low percentage of mice were cured with our Ad-TNF vectors.

abstract: Doctor of Philosophy (PhD)


title: Age-Related Changes in Automatic and Consciously-Controlled Memory Processes

contributor:
Jacoby, L.L.
Psychology

subject: Psychology Psychology

abstract:
Memory retrieval relies on automatic and consciously-controlled processes. However, it is nor clear whether one or both of these influences are affected by age. The present experiments used Jacoby's (1991) process dissociation procedure to separately examine the effects of aging on each process. The results show that age impairs consciously-controlled memory but leaves automatic processing intact (Experiments 1, 2, 5 & 6). Moreover, age-related declines in conscious processes are severe. Elderly adults revealed marked deficits in conscious memory when only three words intervened between study and test (Experiments 3 - 5).

In these experiments (Experiments 1 - 5) impairments in conscious influences left automatic memory as the sole basis for retrieval, which led to "false" recognition errors. Although these errors suggest that older adults may be unaware of the process that underlies their performance (automatic versus conscious), they actually proved as aware as young adults and were highly capable of identifying which form of processing they used (Experiment 6). More importantly, the level of memory ability they demonstrated in the lab corresponded to their performance in the real world. Elderly subjects showed a high correlation between conscious memory failures on lab tasks and self-reported failures in everyday life (Experiment 7). This result suggests that the lab tests used were ecologically valid and predictive of real world functioning. The implications of these seven experiments for memory assessment and rehabilitation are discussed.

abstract: Doctor of Philosophy (PhD)


title: The regulation of carbohydrate and lactate metabolism in exercising human skeletal muscle

contributor:
Heigenhauser, G.J.F.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: The studies described in this thesis were undertaken to examine the mechanism of lactate production in exercise from a standpoint of enzymatic control and investigate the two rate-limiting enzymes which regulate glycogen breakdown and oxidation, glycogen phosphorylase and pyruvate dehydrogenase (PDH). The purpose was to establish the theory that it is the differential rate of flux through these enzymes which determines the extent of lactate accumulation in situations where significant lactate production occurs such as during 30-s bouts of maximal intermittent exercise and during exercise in hypoxia. In the first study, at the onset of maximal exercise, the transformation of PDH was delayed relative to phosphorylase accounting for a greater lactate accumulation. PDH was maximally transformed after 15s and remained elevated until 30s, whereas the transformation of phosphorylase remained elevated at 15s and reverted to resting levels after 30s. Before the third bout of exercise, PDH was nearly 50% transformed and was fully transformed after only 6s, whereas phosphorylase remained at resting levels. The regulation of these enzymes at the last 15s of the first bout and throughout the third bout is consistent with a reduction in glycogenolysis and increased pyruvate oxidation leading to less lactate accumulation. In the second study, at the onset of exercise in hypoxia, there was a delayed transformation of PDH relative to normoxia, accounting for the greater lactate accumulation typically observed in hypoxia. The results from these first two studies suggested that the metabolic inertia of PDH activation may be a factor in the mechanism of lactate production in both maximal exercise and in hypoxia. The third study sought to remove the metabolic inertia of PDH activation during exercise in hypoxia with the infusion of dichloroacetate (DCA). DCA fully transformed PDH at rest and at the onset of exercise in hypoxia. By removing the metabolic inertia of PDH activation with DCA or with prior exercise as in the third bout of maximal exercise in the first study, lactate production was significantly reduced. The findings from these studies demonstrate that the mechanism of lactate production is the result of a mismatch between the rates of pyruvate production and pyruvate oxidation due to the differential catalytic rates between glycogen phosphorylase and PDH under conditions where oxygen is presumed to be limiting such as maximal exercise and exercise in hypoxia. These results contradict the theory that an O2 limitation is the main cause for lactate production ("anaerobic metabolism") and suggest that the metabolic inertia of enzyme activation also plays a role. The data are indicative of a central role for PDH and phosphorylase in the mechanism of lactate production and further question whether O2 is limiting during exercise in healthy humans.

abstract: Doctor of Philosophy (PhD)


title: Determination of Two-Phase Flow Parameters for Nuclear Fuel Channels using a Real-Time Neutron Radiography Method

contributor:
Chang, J.S.
Krishnan, V.S.
Engineering Physics

subject:
Engineering Physics
Engineering Physics

abstract:
Multi-dimensional modelling of two-phase flow requires accurate constitutive relationships for interfacial parameters such as interfacial heat transfer, void fraction distribution, interfacial area, etc. However, existing diagnostic systems for measurement of two-phase flow parameters have difficulty measuring two or three-dimensional void distributions required for determination of interfacial parameters.

In this work, a Real-Time Neutron Radiography (RTNR) system is developed for non-intrusive measurement of two-phase flow parameters in nuclear fuel channels at low thermal neutron fluxes (on the order of 10⁶n/cm²-s). This advanced radiation technique has the advantage of measuring two-phase flow in 3½ dimensions(x,∫dy,z,t) where the ½ dimension refers to an integrated or averaged space dimension. Pipe flow channels, annulus flow channels, MAPLE-type nuclear fuel flow channels, and CANDU-type nuclear fuel flow channels are investigated. Measurements of flow regime, void fraction, void fraction distribution, bubble diameter, bubble velocity, and interfacial area are conducted.

The RTNR system is compared to ultrasonic and optical video measurement systems in pipe flow channels. Good agreement is obtained for flow regime, void fraction, bubble diameter, and interfacial area measurements.

The RTNR system is compared to High-Speed X-ray Computed Tomography (X-CT) and optical video measurement systems in the annulus flow channel. Good agreement is obtained for the determination of flow regime, void fraction, void fraction distribution, and bubble velocity measurements.

Application of the RTNR system to the vertical MAPLE-type 37 rod hexagonal finned fuel bundle and the horizontal CANDU-type 37 rod cylindrical fuel bundle is conducted. Measurements of flow regime, void fraction, and void fraction distribution are obtained and interfacial wave motion is observed. Flow regime observations in the MAPLE-type nuclear fuel channel show good agreement with previous work whereas flow regime observations in the CANDU-type nuclear fuel channel show significant discrepancies with previous work. A new large amplitude stratified wavy (LASW) flow regime is observed by the RTNR images in the CANDU-type nuclear fuel channel. The MAPLE-type nuclear fuel channel is shown to inhibit void migration and bubble coalescence at the entrance to the bundle and significantly affect the flow. The CANDU-type nuclear fuel channel is also observed to influence the cross flow in the core of the rod bundle.

Based on this work, an RTNR diagnostic technique is shown to be successful in measuring two-phase flow parameters in nuclear fuel channels.

abstract: Doctor of Philosophy (PhD)


title: Studies on the Juvenile Hormone-controlled Synthesis of Vitellogenin in the African Migratory Locust, Locusta migratoria migratorioides R. & F.

contributor:
Chen, T.T.
Biology

subject: Biology Biology

abstract: The biosynthesis of the yolk-precursor protein, vitellogenin (VG), induced by juvenile hormone (JH) in the fat body of African migratory locusts, has been studied as a system for analyzing the mechanism of JH-controlled specific gene activation in insects. In order to isolate VG mRNA for further characterization, conditions for the isolation of undergrad VG mRNA-containing polysomes from the fat body of reproductively active females have been defined. The identity of these female-specific heavy polysomes as VG polysomes was confirmed by precipitation of the associated nascent polypeptides with antivitellin serum and by translation of the polysomal RNA in Xenopus oocytes. By EM observation these polysomes were found to contain 40-50 ribosomal monomers. In normal development, accumulation of ribosome monomers in the fat body of female locusts began at about day 4 after emergence (terminal oocyte length = 2 mm), then was followed by the appearance of VG polysomes beginning at about day 8 (terminal oocyte length = 3 mm). Vitellogenin polysomal content reached a maximum at about day 14 (terminal oocyte length = 5-6 mm), and then fell to an undetectable level as the terminal oocytes reached their maximal size (7 mm). In allatectomized (removal of the source of JH) females VG polysomes can be induced by ZR-515 (300 µg/animal) treatment. A single treatment with ZR-515 induced a rapid increase in ribosome monomers and light polysomes in the first 48 hr, but the maximal production of vitellogenin polysomes was observed at 72 hr. After the decay of this effect (12 days after hormone treatment) a second application of ZR-515 resulted in the rapid formation of vitellogenin polysomes without an initial accumulation of ribosome monomers. These and previous results are consistent with the action of juvenile hormone at the gene level.

abstract: Master of Science (MS)


title: Potential causes and mechanisms of postexercise hypotension

contributor:
MacDougall, Duncan J.
Kinesiology

subject:
Kinesiology
Medical Sciences
Kinesiology

abstract: This thesis consists of five studies, conducted with the objective of advancing our understanding of post exercise hypotension (PEH) and its mechanisms. Studies 1, 2 and 3 examined the effects of exercise intensity (30 min of cycle ergometry at 50 and 75% V O2 Peak ), exercise duration (10, 15, 30 and 45 min of cycle ergometry at 70% V O2 Peak ) and the effects of exercising muscle mass (arms vs. legs) on PEH. In all cases, blood pressure was lower after exercise and the magnitude of this decrease was unaffected by the variations in protocol. Heart rate and V O 2 were elevated through much of the hypotensive period in these studies, suggesting that a decrease in total peripheral resistance mediated the blood pressure effect as opposed to a decrease in cardiac output. Study 4 was conducted to determine whether or not the hypotension following exercise is maintained during normal simulated activities of daily living (ADL). This study demonstrated a relative PEH, which persisted for at least 70 min of ADL. Systolic (SBP), diastolic (DBP) and mean (MAP) blood pressure were significantly decreased following exercise as compared to the non-exercise trial as well as from baseline measures. From this study, it can be concluded that acute exercise has the potential to serve as a non-pharmacological aid to hypertension. Study 5 was conducted to determine the possible role of the central serotonergic system as a cause of PEH. While taking a placebo or selective serotonin reuptake inhibitor (SSRI) (randomised order) participants completed 30 min of cycling at 70% of V O2 Peak . Peripheral measures of serotonin (5-HT) were decreased during SSRI treatment, whereas 5-hydroxyindoleacetic acid, was not statistically increased, suggesting elevated central 5-HT levels. However, the significant decrements in blood pressure were similar between trials indicating that the central serotonergic system was not responsible for PEH in a borderline hypertensive population. This thesis was supported by the Natural Sciences and Engineering Research Council of CANADA.

abstract: Doctor of Philosophy (PhD)