title: Studies on the Genetic Origin of Mammalian Mitochondrial RNAs

contributor:
Freeman, K.B.
Biochemistry

subject: Biochemistry Biochemistry

abstract:
The nature and genetic origin of mammalian mitochondrial poly(A)-containing RNA and tRNAs was examined using isolated mitochondria to label these molecules.

The synthesis of poly(A)-containing RNA by isolated mitochondria from Ehrlich ascites cells and rat liver was studied. Isolated mitochondria incorporate [³H]AMP or [³H]UTP into an RNA species that adsorbed on oligo(dT)-cellulose columns or Millipore filters. Hydrolysis of the poly(A)-containing RNA with pancreatic and T₁ ribonucleases released a poly(A) sequence that had an electrophoretic mobility slightly faster than 4Sℯ. In comparison, ascites-cell cytosolic poly(A)-containing RNA had a poly(A) tail that had an electrophoretic mobility of about 7Sℯ . Sensitivity of the incorporation of [³H]AMP into poly(A)-containing RNA to ethidium bromide and to atractyloside and lack of sensitivity to immobilized ribonuclease added to the mitochongria after incubation indicated that the site of incorporation was mitochondrial. The poly(A)-containing RNA from ascites cell mitochondria sedimented with a peak of about 18S, with much material of higher S value. After denaturation at 70°C for 5 min the poly(A)-containing RNA from both ascites cell and rat liver mitochondria separated into two components of 12S and 16S on a 5-20%. (w/v) sucrose density gradient at 4°C, or at 4° and 25°C in the presence of formaldehyde. Poly(A)-containing RNA from ascites cell mitochondria synthesized in the presence of ethidium bromide sedimented at 5-10S in a 15-33% (w/v) sucrose density gradient at 24°C. The poly(A) tail of this RNA was smaller than that synthesized in the absence of ethidium bromide. The size of the poly(A)-containing RNA (approx. 1300 nucleotides) is about the length necessary for that of mRNA species for the products of mitochondrial protein synthesis.

The sedimentation and electrophoretic properties of Syrian hamster cytosolic and mitochondrial methionyl- and leucyl-tRNAs were compared under denaturing conditions. Mitochondrial leucyl-tRNA could be separated into three species by chromatography on RPC-5. Their apparent molecule weights as determined by polyacrylamide slab gel electrophoresis were 23 000 for one species and 24 000 for the other two compared to the five cytosolic leucyl-tRNA species whose apparent molecular weights ranged from 26 000 to 28 000. Mitochondrial leucyl-tRNAs sedimented more slowly than their cytosolic counterparts, again indicating a lower molecular weight. The apparent molecular weights of the mitochondrial methionyl-tRNA were identical or only slightly lower than their cytosolic counterparts as determined by polyacrylamide slab gel electrophoresis.

Individual tRNAs for arginine, asparagine, leucine, lysine, methionine, proline and valine were charged in isolated rat liver mitochondria and shown to be distinct for their cytosolic counterparts by chromatography on RPC-5. By electrophoresis on urea polyacrylamide slab gels it was found that all these mitochondrial aminoacyl-tRNAs were about 70-76 nucleotides long. The unique mitochondrial asparaginyl- and prolyl-tRNAs, not previously identified in mammalian cells, were shown to hybridize to mtDNA. Mitochondrial leucyl-tRNA was separated into 3 peaks on RPC-5 and the first species was shown to be different than a combination of the other two by molecular size and partial RNase T₁ digestion patterns. Each was coded by a separate gene on mtDNA as shown by partial additivity of hybridization. Separate genes for mitochondrial tRNAmᴹᵉᵗ and tRNAfᴹᵉᵗ, separated by RPC-5 chromatography, were also demonstrated. These results bring to 21 the number of individual tRNAs coded by mammalian mtDNA.

abstract: Doctor of Philosophy (PhD)


title: The Programme of 1871: A Modern Instance of Natural Right Argumentation

contributor:
Grant, George P.
Religion

subject: Religion Religion

abstract:
This thesis is a commentary on a newspaper editorial published in the Journal des Trois-Rivieres on April-20, 1871 and entitled "Programme catholique: les prochaines elections". The Programme was composed by a group of French Canadian Catholic journalists who wanted to offer their compatriots practical political advice on the upcoming Quebec general election. In effect, their advice amounted to qualified support of the governing Conservative party.

The authors statement of support for the Conservative party was preceded, however, by an argument that was the basis for their advice. The major premise of the argument affirmed that politics is subordinate to religion; the minor premise, that in a country like Canada every religious community should have the necessary practical freedom to exercise its form of worship.

In making this argument, the authors of the text took a stand on the age old question of Church-State relations. According to the programmistes, the State is "negatively dependent" on the Church. That is the essential relation making for order in society. Care must be taken, therefore, to have that relation reflected in society's institutions.

Study of the Programme is enlightening at at least three different levels. Historically, the text was a controversial issue in the 1871 general election: it revealed a deep division in the Conservative party in Quebec and affected that party's subsequent development. Politically, it presented a coherent account of the structure and operation of Parliamentary Government, with special reference to the constitutional position of Quebec after Confederation. Philosophically, it was a strong argument for an "authoritarian", as opposed to a "libertarian", society: and for the traditional "natural", as opposed to the modern "naturalistic" view of the world.

The bulk of my thesis is devoted, therefore, to explicating, at one level or another, the substance of the Programme.

In my approach, I have tried to combine a classicist's respect for the text before him with a jurist's respect for the case before him. This led me, in the first place, to be careful not to impose any artificial construction on the text. Instead, I have tried to allow the text to speak for itself as much as possible, and indeed even to allow its authors to make their own comments. At the same time, I had to do justice to the text's multidimensionality, and above all to its practical and moral thrust. These considerations resulted in an approach bearing some resemblance to the "case study" method familiar to students of law and administration. This method focuses on an event, on something that presents a clearly defined and usually very limited surface ares, while often giving rise at the same time to far ranging considerations. My concern, then, with the Programme both as a text and as a case prompted me to label my approach "jurisprudential". It is an approach which I believe could usefully be taken up by other students of society.

abstract: Doctor of Philosophy (PhD)


title: Platelet Adherence to Collagen Containing Surfaces

contributor:
Mustard, J.F.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: The first step in hemostasis and thrombosis is the adherence of platelets to the damaged vessel wall. The factors involved in platelet adherence are not well understood, mainly because of the lack of a suitable method to measure quantitatively platelet adherence to surfaces. The aim of the present studies was to develop a quantitative method to measure platelet adherence to collagen containing surfaces. The following results were obtained with this method: (1) In this quantitative method for measuring platelet adherence to collagen-coated glass surfaces and to subendothelium the platelelets are labeled with ⁵¹Cr and adherence can be measured over a large area without sampling bias. Platelets are suspended at pH 7.35, at 37°C in an artificial medium which can be modified as required. The medium contains physiological concentrations of calcium and magnesium and platelet aggregation is prevented by the inclusion of apyrase to degrade any ADP released. There is no plasma present and thus no thrombin generation or fibrin formation occurs. Adherence is measured using a rotating probe device under controlled flow conditions and various surfaces can be tested (collagen-coated glass, everted aorta damaged to expose the subendothelium). (2) Platelet adherence to collagen-coated glass or to subendothelium is greatly reduced in the absence of divalent cations. Thus, methods which measure platelet adherence in the presence of chelating agents are difficult to interpret. (3) Increasing the albumin concentration of the medium decreases platelet adherence, but there is less variation among replicates. (4) Increasing the hematocrit increases the number of platelets adhering to the surface. (5) Platelets adhere tightly to collagen or to subendothelium and are not dislodged by agents which readily deaggregate platelets such as EDTA, EGTA, or PGE₁. (6) Exposure of undamaged endothelium to thrombin increases the number of platelets adherent to the surface and this is blocked by heparin. (7) This method of measuring platelet adherence to collagen can be used to screen drugs which may be useful as antithrombotic agents. The best system is to test the effect of a drug in the presence of 4% albumin and 40% hematocrit, however, for initial screening a simpler system can be used (0.35% albumin, zero hematocrit). (9) Several treatments which modify the platelet surface have been tested for their effect on adherence to collagen. Removal of sialic acid with neuraminidase do not affect platelet adherence whereas treatment with sodium periodate and the proteolytic enzymes thrombin, plasmin and chymotrypsin decrease adherence. (10) UDP and UDPG do not have an effect on platelet adherence to collagen and this observation does not support the collagen: glucosyltransferase theory of platelet adhesion to collagen. (11) Clq, a subcomponent of the first component of complement specifically inhibits platelet adhesion to collagen and may compete with the collagen receptor on the platelet membrane. (12) A wide variety of agents inhibits platelet adherence to collagen-coated surfaces and to subendothelium. Among the inhibitors which decrease platelet adherence in a system containing 4% albumin and 40% hematocrit are agents which chelate divalent cations (EGTA, EDTA, citrate), indomethacin, agents which increase cAMP levels (prostaglandin E₁, dipyridamole, RA 433), methylprednisolone, penicillin G and cephalothin. (13) Aspirin inhibits platelet adherence to collagen-coated surface or to subendothelium, but its inhibitory effect is not evident in the presence of 40% hematocrit or citrated plasma indicating that the conditions of the experiments are important in determining the effect of drugs. (14) Modifications of platelelets by treatment with thrombin, penicillin G or cephalothin which inhibit platelet adherence to collagen or subendothelium do not affect platelet survival. Modification of the platelet surface sialic acid by neuraminidase or periodate is followed by rapid clearance of platelets from the circulation. Thus there is no correlation between platelet adherence and platelet survival. (15) Treatments which decrease platelet to collagen and to the subendothelium also reduce the platelets in hemostasis.

abstract: Doctor of Philosophy (PhD)


title: Three Essays on Firm-Worker Separations

contributor:
Kuhn, Peter J.
Economics / Economic Policy

subject: Economics Economics

abstract: Three aspects of a turnover in Canadian labour markets are presented. First, geographic mobility following job displacement, the permanent and involuntary loss of a job by a worker, is studied. In the Canadian Displaced Worker Survey, 17% of the men, and 9% of the women, find reemployment in a geographically distant labour market. The reemployment hazard of women in the local labour market is reduced by the presence of children, but that for men is unaffected by them. Allowing for a fixed unobserved characteristic, the probability of reemployment in each period, conditional on having not found reemployment earlier, is observed to be approximately constant for a typical person. Looking at unionism, tenure and the cost of job loss in the second essay, I estimate a union tenure-wage markup profile. A markup is the difference between each worker’s predisplacement and best alternative, or postdisplacement, wage. The profile is found to increase more quickly in the union than nonunion sector. This evidence suggests a resolution to a longstanding puzzle in the economic study of unions. In cross section union members’ return to tenure appears to be flatter than that in the nonunion sector, whereas several theories of union behaviour suggest that unions should preferentially redistribute rents to more senior members. Finally, a test of the efficient turnover view of labour markets is conducted using two recent Canadian legislative changes that reduced, and then eliminated, unemployment insurance benefits for those who quit or are dismissed for cause. The theory suggests that firms and workers jointly maximize their wealth which in this case, implies that they will relabel disentitled quitters to groups which may obtain benefits. No evidence of this is observed; however workers, especially female ones, are inhibited from quitting. This is interpreted as evidence against the efficient turnover model.

abstract: Doctor of Philosophy (PhD)


title: Large Scale Plastic Deformation and Fracture for Multiaxial Stress States

contributor:
Embury, J.D.
Metallurgy and Materials Science

subject:
Materials Science and Engineering
Metallurgy
Materials Science and Engineering

abstract:
In considering the fabrication of engineering components from metals in the form of thin sheets (<6 mm in thickness), attention must be given to two important problems: a) the mechanisms by which plastic strain is distributed in the component, and b) the competition between continued deformation and fracture. The description of these processes from a theoretical viewpoint and the completion of an experimental program are complicated by the fact that both problems involve intrinsic properties of the sheet as well as external parameters such as temperature, strain rate and stress state. The objective of this thesis is to characterize the sequence of events which occur during the forming process by giving attention to both types of variables.

The first portion of this work involves a macroscopic approach. An experimental program has been conducted to measure (by using grid techniques) the distribution of strain in a variety of aluminum alloys subject to loading trajectories which range from pure shear to biaxial tension. Equations have been derived to express the occurrence of localized necking and fracture in terms of strain and stress coordinates. These curves, generated by plotting the two events for a wide range of stress systems, may be termed failure maps. If one considers their position relative to the initial yield event, the maps are capable of representing the entire strain history of the sample. In addition, their shape and level can be used a) to establish the relevance of empirical failure criteria, b) to compare the behavior of materials (e.g to illustrate the competition between alloys to form a given component), and c) to examine the influence of stress state on the occurence of a well defined fracture mode.

By varying the heat treatment of some of these alloys, it was possible to promote different fracture modes such as fibrous, shear or intergranular fracture and to examine these modes in terms of the resultant fracture map. The results indicate that the failure criteria applicable to sheet metal forming operations are in good accord with the fractographic evidence, and that one should not only consider the competition between continued deformation and fracture, but also between available fracture modes depending on heat treatment and stress state.

Although the macroscopic approach outlined above gives a broad summary of the straining history of the sample, it is not sufficiently specific to enable a correlation with the microstructure. The second approach of this thesis, at a microscopic level, is concerned with local events occuring inside the material and attempts to elucidate the metallurgical factors which influence the conditions under which a well characterized alloy undergoes the transition from uniform deformation to some form of localized deformation and finally fracture.

A model material (in the form of spheroidized carbon steels) was thus studied to obtain a quantitative description of the microvoiding process leading to fibrous fracture. Careful examinations of the fracture surfaces and the zones adjacent to them enabled a measurement of structural damage resulting from plastic deformation to be established. A detailed theoretical model was developed to relate the damage to continuum quantities such as strain and stress. The model was then extended to describe the process of void nucleation and growth at inclusions under more general stress systems.

Finally, a new description of work hardening characteristics of materials at large strains was presented and related to the foregoing concepts of strain localization and fracture.

abstract: Doctor of Philosophy (PhD)


title: Clerics, Fishermen, Farmers and Workers: The Antigonish Movement and Identity in Eastern Nova Scotia, 1928-1939

contributor:
Shaffir, William
Sociology

subject: Sociology Sociology

abstract: The central thesis of this dissertation is that the Antigonish Movement can be understood as an instance in the sacralization of identity process. The Antigonish Movement developed within Eastern Nova Scotia during the 1930's. It was a self-help social movement characterized by an emphasis on education, as experienced in a succession of small study clubs, and an emphasis on economic co-operation, as practiced in a network of producer/consumer co-operatives. The sacralization of identity thesis simply means that a particular way of life and interpretation of reality became firmly established as a known, predictable, and socially informative pattern of existence within the region of Eastern Nova Scotia during this period. The development of the thesis runs as follows. Identity formation is considered essential for social existence. Dramatic changes in the manner in which social existence is organized creates special problems in the maintenance of any identity formation. Turn of the century industrialization, within Eastern Nova Scotia, can be considered as that type of dramatic change which makes an identity formation precarious. The Antigonish Movement developed within the context of these changes. The way of life and interpretation of reality it sacralized reflected the identity formations of past experience, as well as the new social realities introduced by industrialization. My investigations indicate that the Antigonish Movement reflected both a tradition based on religious/ethnic cultural formation and the modern impetus of reform liberalism, scientific rationality and democratic participation. I argue that the movement synthesized these lifestyles and made their expression possible. The latter process is that of sacralization. People, in the movement, created beliefs that symbolically expressed their co-operative existence in terms of its being "God's own work" and "essential" to the construction of democratic society. In their day to day existence, they were emotionally committed to what they considered to be "rational and scientific" principles of co-operative production/consumption. They ritualized certain key practices that were endemic to the theory and practice of good co-operation. They developed myths to both account for what they were doing and to reconcile any apparent discrepancies in their chosen lifestyles. In this way, a co-operative identity was sacralized in Eastern Nova Scotia. At the level of consciousnes and within social structures, co-operative social existence assumed that predictability and permanence which is characteristic of a recognizable identity.

abstract: Doctor of Philosophy (PhD)


title: Karst development in Ordovician carbonates: Western Platform of Newfoundland

contributor:
Ford, D.C.
Geography

subject: Geography Geography

abstract:
The Appalachian fold belt system in Newfoundland is divided into three tectonic divisions: Western Platform; Central Mobile Belt; Avalon Platform Rocks of the Western Platform range in age from Precambrian to Carboniferous. Major karst areas are found there is Ordovician and Carboniferous rocks. Karst features of the study area (Goose Arm to Bonne Bay Big Pond) are in the Ordovician carbonates of the undivided St. George and Table Head Formations, covering a few hundred square kilometers. Features include karren, sinkholes, sinking streams, and karst springs, caves and other solutional and collapse features.

In the study area multiple fold and faulting episodes complicate the geology. Extensive and probably repeated glaciations have produced rugged terrane with U-shaped valleys and as much as 300m relief on the carbonates. There is variable but thick till cover. A class or classes of ice-scoured closed depressions with internal drainage are recognized. Postglacial karst forms are limited to varieties of karren (mainly littoral), small sinkholes, and cave systems that are inaccessively small in most instances. Distribution of all karst features is highly irregular.

Hydrologic patterns follow fluvial, fluviokarstic and holokarstic drainage. Large number of sinking ponds have seasonal overflow channels. The ground water drainage routes are generally short and shallow, with varied hydraulic gradients. Few instances of ground water route integration to regional springs is found.

The water chemistry of the area displays a tight normal distribution of hardness. This is attributed to the ponding effect. Seasonal trends show an overall increase in total hardness and other parameters, with some ponds showing linear increases and others cyclic variations.

Karst type and distribution is complex and irregular, but both glaciokarstic and karstiglacial development is present. The majority of karst forms point to karstiglacial development where previous karst forms have been modified by ice. Karstification is controlled by geology, rock lithology, hydraulic gradients and glacial scour and infill. Karstic processes continue to operate today, modifying the scoured basins and creating new karst forms.

abstract: Master of Science (MS)


title: Ignatius of Antioch on his Death: Discipleship, Sacrifice, Imitation

contributor:
Meyer, B. F.
Religious Studies

subject: Religion Religion

abstract:
The present dissertation is addressed to a single question: how did Ignatius of Antioch understand his death? Our question is not a new one. On the contrary, it is one that has attracted scholarly attention for over a century. Nevertheless, it is one for which a satisfactory answer is still lacking. Most recent commentators are agreed that Ignatius understood his death in terms of a number of individual themes, images and conceptions. Moreover, the clear tendency of scholarly opinion is to identify the themes of discipleship, sacrifice and imitation as most fundamental to understanding the shape of this aspect of Ignatian thought. In its understanding of each of these three themes, however, scholarship continues to propose views which we do not believe to reflect the thinking of Ignatius himself.

Our dissertation is composed of two parts. In Part I, attention is focused upon the content of present scholarly thinking on the subjects of discipleship, sacrifice and imitation within Ignatian thought and the development of scholarly thinking over the last one hundred years. In the case of each of these themes, we conclude that a reevaluation of each theme is presently called for. In Part II, each of the three themes is studied individually. In discussing discipleship, we conclude that Ignatius actually used the key term μαθητης in a more complex way than that presently supposed. UltimateIy, a new view of how Ignatius used this term in reference to himself facing death emerges--one which understands the term in the light of the themes of endurance and devotion. Secondly, a more cautious definition of sacrifice is presented. Here our view of the problem attempts primarily to be more sensitive to the limitations of the available data and aware of possible alternative lines of interpretation. Finally, Part II approaches the theme of imitation as a question of meaning within Ignatian thought. In particular, Ignatius' associations with the persons of Paul and Christ are examined as parts of Ignatius' understanding of his death.

In brief, the present dissertation supports the contention of scholars that the themes of discipleship, sacrifice and imitation were important parts of Ignatius' understanding of his death. It proposes new understandings for each of these themes.

The essential contribution of this thesis is that it proposes a more adequate foundation for the understanding of Ignatius' view of his death. It critically confronts present scholarly thinking on the issue and proposes a new solution of great consequence to this major question within the field of Ignatian scholarship. A more remote significance of the thesis lies in its subverting certain common generalizations about "early Catholicism," insofar as they are grounded in mistaken assumptions about Ignatius of Antioch and his stance toward his own imminent death.

abstract: Doctor of Philosophy (PhD)


title: Low Temperature Irradiation of Iron, Zirconium and Copper by 10 to 16 MeV Protons

contributor:
Robinson, J.E.
Materials Science

subject:
Materials Science and Engineering
Materials Science and Engineering

abstract:
Scattering and radiation damage parameters are analytically evaluated for 14 MeV neutrons and 10-17 MeV protons on Fe, Ni, Cu, Zr, Nb and Au. Damage energies are computed for the interactions using both elastic and non-elastic data. The theoretical results show that proton encounters deposit a damage-energy greater by factor of two than that calculated for mono-energetic 14-MeV neutron events.

To examine the theoretical results, electrical resistivity measurements are undertaken for Fe, Zr and Cu irradiated at 12 to 17.5K with 10 to 16 MeV protons. The resistivity change is measured as a function of dose. In addition, post-irradiation isochronal annealing is carried out in-situ using a closed-cycle helium-cooled cryostat.

Values of the resistivity damage rate are determined from the experimental plots of Δρᵢ versus Φt, and compared with the values of dΔρᵢ/dΦt estimated from the theoretical damage-energy results. Also, the observed stage-I recovery is analysed in terms of the corresponding recovery reported for electron and fast-neutron irradiations. The data analysis also includes a discussion of the relation between the present 16-MeV proton data and published data estimated from a fusion-reactor spectrum.

The results presented in this thesis indicate that 16 MeV protons approximate the anticipated damage due to a fusion-reactor spectrum. It is also shown that protons create a damage structure similar to a superposition of the damage structures generated by electrons and fast-neutrons. The sample state of imperfection is shown to influence the induced damage-state in proton irradiation.

abstract: Doctor of Philosophy (PhD)


title: Majority-Minority Relations in a Multicultural Society: The Case of Switzerland

contributor:
Brotz, Howard
Sociology

subject: Sociology Sociology

abstract: Switzerland, a country which has managed to weld four different language groups and two major religions into a harmonious unity has long been a major enigma in an age of cultural nationalism. Currently it is one of the few national communities without a shared culture whose overall political unity is not threatened. This work attempts to trace major sources of Swiss coexistence as well as some of the problems now facing Switzerland. Because most of the literature in race and ethnic relations has focused on causes of conflict and discord, majority-minority relations in Switzerland has received relatively little attention. The first part of the study investigates various attempts to explain the Swiss case. Explanations such as cross-cutting cleavages and the politics of consociational democracy are given special attention. The hypothesis of cross-cutting cleavages, which currently represents the dominant explanation of Swiss coexistence, says in essence that cross-cutting cleavages such as religion, language, etc., tend to create cross-pressures among the population that serve to moderate the intensity of political conflict. While this view helps explain the stability and cohesion of the Swiss polity it is shown to be overly simplistic and reductionist. Another major explanation is that of consociational democracy. Although it, too, contributes to our understanding of Swiss harmony, by emphasizing the conscious and deliberate efforts of autonomous elites it neglects the role of popular sentiment and public opinion. This study focuses on the transmission of values, and the relationship between public opinion and attitudes and cores values in a multicultural setting. In order to explore the salience of popular sentiment and public opinion in contributing to Swiss coexistence, an analysis of Swiss history textbooks from French and German, Catholic and Protestant Switzerland was carried out. It was found that in contrast to Canada and South Africa, the school curriculum tends to unite rather than divide the various cultural groups by de-emphasizing those historical themes which feed intergroup resentment. Even though the authors present various interpretations of some events, there is an underlying consensus of what the Swiss state should stand for. In addition, the textbooks promote a positive sense of Swiss identity which transcends a narrow linguistic or cultural definition of nationhood. A survey administered to French and German Swiss youth reinforces this interpretation. A variety of indicators show that the German Swiss who comprise three-fourths of the population lack what may be called a "majoritarian outlook". While the opposite is not q completely true of the French Swiss minority, they do not display that sense of relative deprivation that is often associated with sociological minorities. When asked why they were proud to be Swiss, both French- and German-speaking youth gave political answers considerably more often than any other reasons. Thus, there appears to exist "a certain Swiss outlook" which unites the Swiss cultural and linguistic groups. This does not mean that Switzerland has solved all problems of a cultural and ethnic nature. The Jura question and the foreign worker problem remain two problematic issues in the conduct of majority-minority relations in Switzerland. A solution to the Jura situation now seems to be in sight. In contrast, the foreign worker problem which involves a non-national minority remains unresolved. This points to the fact that Swiss policy toward non-citizen minorities is at variance with the treatment of citizen minorities. In concluding this study we propose an important corollary to pluralist thought which posits an implicit correlation between social heterogeneity and political instability. Our basic proposition is that a "civic culture", moderates social conflicts and promotes stability in multicultural settings.

abstract: Doctor of Philosophy (PhD)


title: Formation, Structure and Composition of Anodic-Oxide Films on Beryllium

contributor:
Kelly, R.
Metallurgy and Materials Science

abstract:
The formation, structure and composition of anodic-oxide films on Be is investigated. According to the choice of electrolyte, porosity, dissolution and crystallinity can be varied almost at will for the formed anodic films. Also the procedure for the anodic sectioning of Be is described and applied to determining the depth distributions of energetic ⁸⁵Kr ions.

The presence and the distribution of electrolyte components that are incorporated into the anodic films are investigated by the photon-emission technique. The depth profiles of the incorporated species are correlated with the mechanism of film formation.

Finally, a criterion for the structure of anodic oxide films on metals is developed based on the kinetics of the formation and crystallization processes of the various oxides. The criterion is applied and found to work successfully with all systems for which information is available, whereas for unstudied systems it for which information is enables predictions to be made.

abstract: Doctor of Philosophy (PhD)


title: Backscattering of 5-15 keV Light Ions from Silicon

abstract: In this thesis the scattering of hydrogen and helium ions, in the incident particle energy range 5-15 keV, from silicon targets is studied both theoretically and experimentally. In the theoretical treatment, electronic and nuclear energy losses are included in a computer simulation model. The computer simulation technique has been developed to study the interaction of the incident ions and target atoms for an incident reduced energy range 0.05<ε₀<20 of interest in fusion research. The theoretical model is based on a Thomas-Fermi interatomic potential and experimental values for the electronic energy loss coefficient. The backscattered energy and angular distributions are calculated by following the histories of 5,000 to 10,000 particles. An experimental system using the time-of-flight technique has been developed to measure the energy spectra of light ions and neutrals backscattered from solid surfaces thus permitting a comparison of the theory with experimental data for a well characterised target. To test the time of-flight technique, ions and neutrals, were scattered from thin silver films (20-40 Å) evaporated on silicon substrates. From the measurements it was found that the sensitivity of the technique is better than 1/20 of a monolayer for silver on silicon. The energy resolution for helium scattered from these targets was found to be 10-15% which is consistent with the time-of-flight resolution and the electronic-loss energy broadening. To measure the energy of the backscattered particles, time-of-flight spectra for hydrogen and helium scattered from silicon were recorded. These spectra were then transformed to energy spectra. The comparison between the experimental and theoretical results showed good agreement down to a backscattered energy of 500 eV (cut-off energy due to detector calibration limits). A number of experiments were done to measure the charge fractions of the backscattered H and He particles from a silicon target. For hydrogen scattering no surface peak were observed and also there was no penetration effect on the charge fractions. This is an indication that hydrogen neutralization occurs at the surface. On the other hand, in the helium case peaks were observed in the charge fractions corresponding to surface scattering. This indicates that helium bound states occur inside the target. Finally, the effect of surface cleaning was studied. The results showed that a factor of 2 increase in ion yield was observed after cleaning the surface by 5 keV neon bombardment. The reduction in the charge fraction for the practical surface was mainly due to carbon and oxygen impurities on the surface.

abstract: Doctor of Philosophy (PhD)


title: Factors Affecting the Activity of Guanylate Cyclase in Lysates of Human Blood Platelets

contributor:
Haslam, Richard J.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
The mechanism by which physiological stimuli increase cyclic GMP formation in platelets or in other cells is unknown. Agents that promote the formation of cyclic GMP in intact cells have in general not been found to stimulate the activity of guanylate cyclase [GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2.] in broken cell preparations. Therefore, possible mechanisms for the activation and control of guanylate cyclase activity in platelets were investigated in this thesis.

It was found that over 90% of the total guanylate cyclase activity is present in supernatant fractions of hypotonically lysed platelets. Platetet particulate fractions contained no guanylate cyclase activity that could not be accounted for by contaminating soluble enzyme, suggesting that physiological aggregating agents may increase cyclic GMP levels in intact platelets through the effects of intermediary factors. Because of the possibility that soluble as well as particulate factors may be involved in the control of enzyme activity, whole platelet lysate was used in studies of the properties and activation of guanylate cyclase.

Under optimal ionic conditions (4.0 mM-MnCl₂), the specific activity of guanylate cyclase in fresh platelet lysates was about 10 nmol of cyclic GMP formed/20 min per mg of protein at 30°C, which is higher than that of any other mammalian cells or tissues studied. Activity was 15% of optimum with 10.0 mM-MgCl₂ and negligible with 4.0 mM-CaCl₂. Synergism between MnCl₂ and MgCl₂ or CaCl₂ was observed when [MnCI₂] ≤ [GTP]; under more physiological ionic conditions (Mg²⁺ present), micromolar concentrations of Ca²⁺ stimulated enzyme activity by about 50%.

Lower than optimal specific activities were obtained in assays containing large volumes of platelet lysate, owing to the presence of inhibitory factors that could be removed by ultrafiltration. Adenine nucleotides and glutathione accounted for less than 50% of the inhibitory activity. The combined effects of inhibitory factors and of suboptimal ionic conditions are likely to lower the guanylate cyclase activity in intact platelets to almost negligible values in the absence of activating factors.

Dithiothreitol (5.0 mM) and N-ethylmaleimide (0.1 mM) inhibited the activity of platelet lysate by about 70 and 50%, respectively. Preincubation of lysate for 60 min at 37°C increased guanylate cyclase activity on average by 225%. This effect could be blocked with dithiothreitol or N-ethylmaleimide, but dithiothreitol could not fully reverse activation once it had occurred. Oxidants such as 4,4'-dithiodipyridine (0.04 mM), diamide (0.4 mM) and tert-butylhydroperoxide (1.0 mM) increased enzyme activity on average, by 40, 87 and 165% respectively. Neither diamide nor tert-butylhydroperoxide had an effect on enzyme that had been preincubated or treated with N-ethylmaleimide.

Sodium azide (10.0 mM) increased guanylate cyclase activity by an average of 335%; this effect was both time- and temperature-dependent. Activation by sodium azide was not prevented by dithiothreitol. Sodium nitroprusside (1.0 mM) increased enzyme activity by about 1000%; this effect could be blocked by preincubation or by tert-butylhydroperoxide, but not by either dithiothreitol or N-ethylmaleimide.

abstract: Doctor of Philosophy (PhD)


title: Factors Affecting The Admission Of Applicants To A Medical School

contributor:
Rosenblum, Jerry
Sociology

subject: Sociology Sociology

abstract: The purpose of this research is to examine the admissions process in which applicants to medical school are selected. It is argued that structural conditions such as a decrease in occupational demand and an increase in educational supply will result in a greater emphasis upon ascriptive values rather than achieved values. A sampling of applicants from 1969 to 1975 who were involved in the admissions process at the medical school was conducted. As well, 73 percent of the 1975 assessors (N=289) who were involved in the admissions process were also analysed. Both 1975 assessors and applicants were mailed a questionnaire which probed their attitudes to those factors which can be present in the selection process. An analysis of the data revealed that academic marks were less differentiated over time and declining in importance in importance in the admissions process. Only sex was found to be increasing in importance over time. Path analysis of the 1975 data demonstrated the direct and indirect effects of ascribed variables such as sex, age, social class, family size and geographical place of residence.

abstract: Doctor of Philosophy (PhD)


title: "Truly This Man was the Son of God": The Christological Focus of The Markan Redaction

contributor:
Meyer, B.F.
Religious Studies

subject: Religion Religion

abstract:
Since the rise of redaction criticism in the early 1950's, the attempt to reconstruct the theological visions which motivated the decisive redactors of the Synoptic Gospels has commanded a good deal of scholarly attention and effort. After a quarter-century of work, however, the Gospel of Mark remains an enigma; no particular trend in the interpretation of this book been able to win the agreement of a substantial majority of commentators. This dissertation has been undertaken with the intention of making a fresh star towards the establishment of a solid understanding of the message of Second Gospel.

With respect to method we join with a small, but growing, group of scholars who object to the dominant practice of redaction criticism, which is to make source analysis the first step in interpretation. Instead, we hold to the view that the theology of the redactor is most likely to be accessible not through the isolation of those words and phrases which appear to have originated from redactional activity, but through the study of the entire Gospel as the final product by means of which the evangelist intended his message to be heard. We have taken this abstention from considerations of the history of the Synoptic tradition a step further by declining to allow the widely-held view of Mark's priority to serve as a methodological presupposition.

Many recent efforts in Markan-studies have argued that the redaction took shape in Syria or Palestine in a community with strong Jewish Christian characteristics. We find that this growing trend is of doubtful value, and ought to be reversed. The Second Gospel was produced by and for Gentile Christians; consequently, judgments of plausibility must be founded upon the recognition that out nearest access to the Markan environment is to be found not through Palestinian Jewish sources, but through the early literature of the mission to the Gentiles: the Pauline correspondence.

Building our analysis upon the foregoing considerations, we come to the comparatively novel conclusion that the issue which most engaged Mark's attention was the opposition which he saw to exist between the divine and the human. This we have termed "the God/man polarity"; we find that it pervades the Gospel, almost to the exclusion of the motif of a cosmic conflict between God and Satan. The God/man polarity is held to be overcome in and through Jesus the God-man, as is revealed in 15:39.

This interpretation arises in part from a new understanding of the Markan use of the titles "Son of Man" and "Son of God", for Mark, means a human being; paradoxically, he has Jesus take up the title at precisely those junctures where he claims more-than-human significance, and thus links the title to the theme of blasphemy. This theme represents Jesus' claim to an authority which transcends the divine/human distinction. "Son of God" clarifies the paradox by ascribing to the man Jesus intrinsic divinity.

Despite its resemblance to traditional Christian teaching, this interpretation of Mark has few precedents in current critical scholarship. Commonly, Mark's portrayal of Jesus has been set into a context of "low", typically Jewish-Christian Christology or into a positive or negative relationship to the alleged Hellenistic type known as the "Divine Man". The major contribution of this thesis is, then, to establish as critically viable the view that Mark originated as a product of the mainstream of Western Christianity and that a God-man Christology, which is well attested both before and after Mark, exercised a decisive influence over the final redaction of this Gospel.

abstract: Doctor of Philosophy (PhD)


title: Sedimentology of a Prograding Shallow Marine Slope and Shelf Sequence, Upper Jurassic Fernie-Kootenay Transition, Southern Front Ranges

contributor:
Walker, R.G.
Geology

subject: Geology Geology

abstract: The Fernie-Kootenay progradational transition consists of 10 interpretable facies described in ascending order. A marine greensand (2-7 m thick) lies at the base. It is overlain by 4 turbidite facies (totalling about 50 m) deposited on the prograding slope. Thin (1-50 cm) Bouma B and BC sandstones with solemarks (NNW flow) are interbedded with bioturbate siltstone. Next is a shallow marine facies of interbedded thick (12-485 cm) sandstones and bioturbate siltstones. Sandstone beds have sharp, toolmarked (NNW) bases and rippled, bioturbated tops. Internal structures are hummocky cross-stratification, and low-angle divergent and broadly trough-shaped sets of parallel lamination which probably represent primary hummocky cross-stratification. These beds result from reworking by variably-oriented currents during deposition from a seaward storm surge density current over fairweather platform sediments. A thick (7-34 m) sharp-based sandstone unit lies on siltstone of the previous facies. Long, low-angle divergent sets of parallel lamination dip in some preferred direction at each locality (especially to the E and SSE). The facies can be interpreted as shoreline beach-acolian deposits amalgamated onto a storm sand bed. A thick unit (average 7-8 M) of trough crossbedded sandstone (N and E flow) follows and represents the deposits of braided streams. Coastal plain coal, siltstone and crevasse splay sandstone cap the sequence. Facies can be recognized in core and develop characteristic nuclear log patterns. At the southern end of the shallow, elongate (N/S) basin offshore storm surge currents deposited shoreline sand on the platform (reworked into hummocky cross-stratification) and prograding slope (turbidites). As the platform built up to shallow depths, rapid progradation of small, marginal, river- and wave-dominated systems superimposed shoreline facies on hummocky sandstone beds, producing northward progradation of the coast. Sediment was derived from the Cordillera and supplied by large north-flowing and smaller east-flowing braided rivers.

abstract: Master of Science (MS)


title: The study of the effect of thermal cycling on the tool life in intermittent cutting processes using the finite element technique

contributor: Mechanical and Manufacturing Engineering

subject:
Manufacturing
Mechanical Engineering
Manufacturing

abstract: The objective of this thesis is to investigate the influence of thermal cycling on tool life in intermittent cuting processes. Particular emphasis is given to the peripheral milling process. In intermittent cutting processes, it has been established that the thermal cycling is the most significant factor which controls the type of failure and the life of cutting tools. The previous theoretical studies of the thermal cycling were based on strongly simplified models. The experimental studies were based on the measurement of the tool/chip interface temperature in the cutting period. Consequently, any implications for tool wear or breakage could only be indirectly estimated. In this work, the thermal cycling is studied by means of finite element computation of the transient temperatures and stresses in the tool wedge. The finite element formulation of the energy equations and the associated boundary conditions, which govern the heat transfer mechanism, is developed for the intermittent cutting processes. A two-dimensional tool/chip model is developed which reflects the interaction between the heat sources, and provides the capability of computing a complete temperature field. The computed temperature field is then used to determine the thermal stresses. The computation of a complete temperature field and the associated thermal stresses is necessary to explain experimentally determined characteristics of tool wear, cracking and breakage. The transient temperature field in both the chip and tool, and the corresponding thermal and mechanical stresses, are computed for the peripheral milling process with different cutting conditions. The theoretical results are correlated with experimental data. The experimental data are taken, mostly, from the tests of Barrow and Yellowley ⁽¹²⁾ and from similar tests conducted by the author. The experimental work concentrates on the flank wear of both high speed steel and sintered carbide milling cutter. It is found that the cutting time ratio has significant effect on tool life. The correlation shows that the number of thermal cycles is the most important parameter which affects the tool life in peripheral milling. The thesis starts with a statement of the problem and the scope of this work in Chapter 1. Chapter 2 provides a summary of the state of knowledge in the area of tool damage in intermittent cutting processes. The temperature problems in continuous and intermittent cutting process are discussed in Chapter 3. The mathematical modelling and the finite element formulation of the heat transfer problem are developed in Chapter 4. The modelling of the cutting process and the computation of the transient temperature distribution are presented in Chapter 5. Chapter 6 is devoted to the presentation and discussion of the computed thermal stresses. The important parameters which may affect the tool flank wear in milling are established and correlated to the experimental data in Chapter 7. Finally, Chapter 8 provides conclusions and recommendations for further research. Specifically, this thesis provides the following contributions: 1. The mathematical modelling and the finite element formulation of the transient heat transfer problem in intermittent cutting (Chapter 4). 2. Derivation of an automatic time step control algorithm for two-point recurrence schemes for the first order ordinary differential equations (Chapter 4). 3. Development of a two-dimensional tool/chip model for the cutting process (Chapter 5). 4. Implementation of a software system, based on he developed models, to compute the temperature and stress fields (Chapter 5 and 6). 5. The study of the influence of thermal cycling on tool flank wear in peripheral milling based on correlating the computed results with experimental data (Chapter 7).

abstract: Doctor of Philosophy (PhD)


title: Pluralism and Truth in Religion: An Analysis and Critique of the Idea of Existential Truth Proposed by Karl Jaspers as a Resolution to the Problem of Pluralism and Truth

contributor:
Weeks, Ian G.
Religious Studies

subject: Religion Religion

abstract: In simplest terms, this thesis is an analysis and critique of Karl Jaspers' discussion of one of the central problems facing contemporary religious thought -- the problem of religious truth as it arises within contemporary consciousness of religious pluralism. Specifically, it looks at Jaspers' affirmative answer to the question, "Can more than one religion be true?" and seeks to determine the adequacy of the idea of truth whereby Jaspers explains such a possibility. It is, then, an analysis of Jaspers' idea of "existential truth" or, more exactly, of his use of that idea in explaining religious truth in a situation of religious pluralism. While finding Jaspers' thought influential and important, the thesis concludes that it is finally inadequate, and develops a series of related criticisms explaining this inadequacy -- criticisms which simultaneously point toward other ways of approaching the question of religious truth which might be more adequate to the reality of religious pluralism.

abstract: Doctor of Philosophy (PhD)


title: Role of RNA and Protein Synthesis in Rabbit Ovarian Follicular Testosterone Production

contributor: Medical Sciences (Growth and Development)

subject:
Medical Sciences
Medical Sciences

abstract:
The role of RNA and protein synthesis in follicular testeterone production has been investigated in the rabbit ovarian follicle in vitro.

lsolated follicles were incubated (usually 2 hours) with labeled amino acids or uridine plus LH, cyclic AMP or cyclic GMP alone, or together with various metabolic inhibitors.

In dose response studies, testosterone production was stimulated at all concentrations of LH (0.1 to 10 μg/ml) tested (p < .05), with optimal stimulation occurring at 5 μg LH/ml (p < .01). However, a significant uptake of ³H-leucine into follicular protein occurred only at > 2.5 μg LH/ml (p < .01), with optimal stimulation occurring at 5 and 10 μg LH/ml. Cyclic AMP (5 and 10 mM) enhanced both testosterone production and the uptake of ³H-leucine into follicular protein (p < .01). Lower cyclic AMP concentrations were ineffective. Neither LH nor cyclic AMP had any effect on the incorporation of labeled uridine into follicular RNA.

In time course studies, testosterone was stimulated within 15 minutes (p < .01), in the presence of LH (5 μg/ml) or cyclic AMP (5 mM). The incorporation of ³H-leucine also increased with time in both LH and cyclic AMP treated follicles, compared to controls, but a significant difference was observed only after 90 and 60 minutes, respectively (p < .01). However, electrophoretic fractionation and radio autographic examination of total follicular proteins after exposure, of LH and ³⁵S-methionine for 15, 60 and 120 minutes showed no apparent difference in the distribution of protein bands when compared to controls.

Actinomycin D (20, 80 and 160 μg/ml) together with LH (5 μg/ml) inhibited the incorporation of ³H-uridine into follicular RNA by 79, 85 and 86%, respectively (p < .01). At these concentrations, no inhibitory effect on LH-induced testosterone production was observed. Paradoxically, Actinomycin D (1 μg/ml) enhanced LH-induced testosterone production above that elicited by LH alone.

Cycloheximide (20 and 10 μg/ml) inhibited LH-induced testosterone production by 64 and 57% (p < .01), as well as the uptake of ³H-leucine into follicular protein by 94 and 93%, respectively. However, cycloheximide (1 μg/ml) did rot inhibit LH-induced testosterone production, yet inhibited ³H-leucine incorporation by 81.7%. Similarly, puromycin (40 μg/ml) inhibited LH-induced testosterone production by 66%, and the uptake of ³H-leucine into protein by 74% (p < .01). However, puromycin (10, 1 or 0.1 μg/ml) did not inhibit LH-induced testosterone production, yet ³H-leucine incorporation was inhibited by 58, 37 and 31%, respectively (p < .01).

The methylxanthines, theophylline (25, 10 and 1 mM) and MIX (5 and 0.5 mM) had no synergistic effects with cyclic AMP on follicular testosterone production. However, these methylxanthines inhibited the incorporation of ³H-uridine (35 to 68%) and ³H-amino acids (45 to 69%) into follicular RNA and protein.

Cyclic GMP (25, 10 and 1 mM) had no stimulatory effect on follicular testosterone production or the uptake of protein. However, cyclic GMP (25 and 10 mM) significantly enhanced the uptake of ³H-uridine into follicular RNA (p < .01).

These data collectively suggest that de novo RNA and protein synthesis are not required for acute LH-induced testosterone production in the rabbit follicle.

abstract: Doctor of Philosophy (PhD)


title: The genetics of the behavioural and physiological responses of Drosophila melanogaster to the insecticide malathion

contributor:
Threlkeld, S.F.H.
Biology

subject: Biology Biology

abstract: i) the more neglected of the two components of the adaptive response of insects to biocides, the behavioural (avoidance) response was investigated and found to be made up of a basic aversive and a secondary dispersive component. ii) natural populations were found to possess a large amount of genetically determined variation in both physiological and behavioural responses to malathion. There is also evidence that these characteristics have been affected by selection in the local populations. iii) the relationship between avoidance and resistance in natural populations indicates that both responses are independently modifiable by selection. iv) a class of X-linked mutations was induced which show a negative correlation between resistance and avoidance. These mutations may prove useful in further studies of resistance and avoidance mechanisms (eg. via genetic mosaic studies), and they may also represent a class of mutations which provide co-adapted changes in responses that may prove to be important in some evolutionary situations. v) practical methods (already published) for assaying avoidance and resistance were developed, which may prove themselves to be useful in studies of economically important insects.

abstract: Doctor of Philosophy (PhD)


title: Stabilization of the Skyrmion by the Quantisation of Collective Vibrations and Rotations

contributor:
Preston, M.A.
Physics

subject: Physics Physics

abstract:
The classical solitons of the minimal σ-model, the Skyrme model without the quartic term, are known to be unstable to scale variations (Derrick's theorem). Although it has been suggested that these solitons might be stabilized by quantum effects, this possibility has not been adequately investigated. Existing treatments lead to new instabilities due to the improper introduction and treatment of collective and intrinsic degrees of freedom.

In this work, we detail the quantisation of collective vibrations and rotations of the Skyrmion in the Dirac formalism for constrained Hamiltonian systems in which we include intrinsic pion field fluctuations. We show that in the absence of the quartic term, the soliton, which disappears in the classical limit, is stabilized by quantum effects alone. The coupling between rotations, vibrations and the intrinsic pion field is found to play an important role in the stability of the soliton.

We derive and solve the Skyrmion equation of motion which now includes quantum corrections leading to the stability of the soliton. The stable soliton is shown to possess a symmetry under scale transformations. In either limiting case of rotations or vibrations only, the soliton is shown to be unstable. On the other hand, the rotating vibrating Skyrmion is stable yet it has different properties in different quantum states, a desirable physical property exhibiting the fluid nature of the Skyrmion.

Comparison with the static properties of baryons and the conventional Skyrme model shows that the qualitative agreement with experimental results is not significantly altered by the presence or absence of the quartic term.

abstract: Doctor of Philosophy (PhD)


title: Pulse Train Duration Discrimination and the Timing of Synchronization and Continuation Phase Interresponse Intervals

contributor:
Kristofferson, Alfred B.
Psychology

subject: Psychology Psychology

abstract:
The purpose of the present investigation was to examine the nature of the timing mechanisms used by humans in two very distinct tasks and to determine whether there was any evidence to suggest that there was a common timekeeper. The duration discrimination experiment involved the presentation of a train of isochronously spaced auditory pulses with the interval between the last two pulses either slightly longer or shorter than the interval between any other two immediately successive pulses. The subject was instructed to make a judgment as to whether the final interval was long or short relative to the preceding intervals. This task was patterned after Kristofferson's (1980) many-to-few duration discrimination task which did not incorporate an explicit pulse train preceding the test stimulus. The second task, which was modelled after Wing (1973), involved two phases of repetitive finger tapping. In the first phase, a train of auditory pulses was presented to the subject and the subject was instructed to tap a Morse telegraph key in synchrony with the pulses. The second phase was a continuation of the first in the absence of any pulses. Subjects were instructed to continue tapping at the rate defined by the exogenous pulses in the synchronization phase. The main reason for using the pulse train duration discrimination method was to evaluate the role of using explicit standard in the context of duration discrimination. Using Kristofferson’s (1976) Real Time Criterion Model to obtain variance estimates of the internal timekeeper, it was possible to determine how those estimates changed with changes in the base duration. The function relating variance to base duration is flat over short base durations and rises in accord with Weber’s law over longer base duration. This is in contrast to earlier findings with the same subject and similar amounts of practice in which the implicit standard many-to-few method of duration discrimination was used. In that experiment a quantal step function emerged (Kristofferson, 1980). This difference implies that the nature of the stimulus plays an important role in the functioning of the internal timekeeper. More specifically, it appears that implicit standards elicit a quantal timekeeping mechanism whereas explicit standards elicit a quantal timekeeping mechanism. Explicit standards appear to elicit timekeeping mechanisms that obey Webster’s law. Webster’s law also characterizes the relationship between the variance and mean of the internal timekeeper in the continuation phase of the finger tapping experiment. After extensive and concentrated practice, it was shown that the above relationship is better described as being linear in timekeeper standard deviation than in timekeeper variance. Since no stepwise increments occurred in these functions, it seems unlikely that a quantal timekeeper is involved in the timing of interresponse intervals. Thus, the statistical principle of timing appears to apply to both explicit standard duration discrimination and the timing of repetitive finger taps in the form of a proportional standard deviation model. Although Weber’s law better characterizes the tapping functions general, one subject’s bioas corrected timekeeper variance versus mean function is very similar to his step function obtained in a many-to-few duration discrimination task. This similarity suggests that the motor timekeeper may have quantal characteristics under some circumstances and that the perceptual timekeeper may be related to the timekeeper involved in motor movement. A second reason for using the tapping paradigm was to evaluate Wing’s (1973) Two Process Model over a wider range of base temporal intervals. In this regard all of the predictions of the Two Process Model were upheld when it was applied to the short base temporal intervals (T less than or equal to 466 msec) but a major prediction of the model often was not borne out when the model was applied to longer base intervals (greater than or equal to 734 msec). It was concluded that it is appropriate to apply the model to evaluate tapping performance using base intervals in this shorter range, but that its application to base intervals in the upper range is probably inappropriate.

Although the synchronization phase of the tapping paradigm has been used in the past primarily to start and set the motor timekeeper for controling continuation phase tapping, it was here evaluated with the use of the Stimulus as Clock Model. This new model, which has its roots in the Two Process Model, evaluates synchronous interresponse interval tapping performance. The model accurately predicts one major characteristic of the timing of synchronization phase timing of interresponse intervals. However, its utility in terms of helping one understand the nature of the internal timekeeping process is limited.

The role of concentrated practice was examined in the context of both experimental paradigms. In both, practice steadily and significantly reduced variability in performance. Such a reduction played a major role in the shape and location of the variance functions and thus in estimates of various parameters.

Results of the two experiments are discussed with reference to previous investigations of response-stimulus synchronization with an attempt to integrate the vastly different results on a theoretical level. This discussion led to a new method by which to generate various parameters of the internal timekeeping mechanism.

abstract: Doctor of Philosophy (PhD)


title: Production and Reproduction in Waged Domestic Labour Processes: A Case Study of Housekeeping Services Franchises in Southern Ontario

contributor:
Chouinard, Vera
Geography

subject: Geography Geography

abstract:
This thesis is a study of the commodification of domestic labour in a particular type of domestic labour firm, housekeeping services franchises, in southern Ontario. Specifically, I investigate the labour-related experiences of the women employed in these franchises. There are two goals: (1) to draw out, describe, and analyse the relations and processes within which women engage while employed as workers in housekeeping services franchises and (2) to devise conceptual tools that can be used to refine and enhance explanations of waged domestic labour processes.

I designed the project in three phases. I was employed at a housekeeping services franchise in Hamilton for three and a half months in the Spring of 1990. During the Fall of 1990 and Winter and Spring of 1991 I carried out multiple-depth conversations with 14 women employed as franchise housekeepers and ten interviews with managers/owners of franchises in southern Ontario and head office personnel. The analysis and write-up began in May 1991 and was completed in February 1993.

The thesis as a report of this research can be divided into three areas, methodology, theory, and topic. Methodologically, I implement a set of feminist principles drawn from a feminist marxist framework. Theoretically, I offer a set of abstractions which together conceptualise waged domestic labour processes in a post-1973 organisation of production relations: 'total labour', production regime, class formation, and gender formation. These concepts in part explain and in part interpret workers' experiences of waged domestic labour processes. Topically, I extend domestic labour studies to include waged domestic labour processes that generate surplus value. I focus on the transformation of the traditional relation of "mistress and maid" to that of "mistress and manager" and "manager and maid".

abstract: Doctor of Philosophy (PhD)


title: Studies of the Cellular Basis of Immunity at Mucosal Surfaces

contributor:
Bionenstock, J.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
The origins of the immunoglobulin-containing cells in the intestinal, respiratory, mammary, and genital tissues were studied in mice, rats, and guinea pigs by using an adoptive lymphocyte transfer method. Proliferating lymphocytes (lymphoblasts) were obtained from various donor lymphoid sources and radiolabelled in vitro with either ³H-thymidine or ¹²⁵-deoxyuridine. Radiolabelled lymphoblasts were then injected into the circulation of recipient animals. Twenty-two - 24 h later, various tissues taken from recipient animals were examined for the presence of radiolabelled donor cells by either radiocounting or autoradiographic techniques. Furthermore, radiolabolled B-cells containing different immunoglobulin isotypes were identified in mouse tissues by a combination of immunofluorescent staining with autoradiographic procedures. It was found possible to greatly accelerate this procedure by the use of liquid scintillation fluid so that ³H-thymidine-labelled cells could be identified in less than 24 h as opposed to 4-6 wks in the absence of scintillation fluid.

In mice and rats, mesenteric lymph node (MLN) lymphoblasts showed a propensity to selectively localize in the cut mucosa. Careful examination of other mouse tissues revealed that MLN lymphoblasts were present, not only in the intestinal lamina propria, but also beneath the mucosal epithelia of the respiratory and genital tracts, the mammary glands and in the MLN. In these mucosal tissues approximately 60% of these cells contained IgA and 25% contained IgG. In peripheral lymph noded (PLN), a few labelled MLN cells were observed and 40% of these contained IgG, whereas only 8% were of tho IgA isotype. The preference of MLN to populate mucosal sites was clear from the results.

In marked contrast, when labelled PLN cells were adoptively transferred, the majority returned to their sites of origin and contained IgG. Of the small number of labelled PLN cells found in mucosal tissues, approximately equal percontages (30%) of IgA- and IgG-containing cells were soon.

Dividing cells prepared from bronchial (mediastinal) lymph nodes (BLN) showed a propensity to localize in the lungs rather than in the intestine or lymph nodes. However, tho predominant immunoglobulin content of these donor cells in tho gut, lungs, and MLN was IgA. Thus, the BLN made a quantitatively minor, but presumably significant, contribution to the IgA plasmacytes found in the gut lamina propria; in the lungs, BLN made a quantitatively major contribution to population of IgA-containing cells residing in the lung mucosa.

It was concluded that, in rodents, the MLN was a major contributor of the immunoglobulin-containing celIs beneath the mucosal epithelia of the gut, lungs, cervix, and vagina and gestational mammary glands. Thus, lymph nodes draining two mucosal surfaces, though differing in IgA plasmacyte precursor content, both possessed cells destained to localize in mucosal tissues. Furthermore, there was organ specificity for the distribution of these cells; those immediately derived from the lymph nodes draining the bowel tended to return to the bowel, whereas those from the lungs tended to return to the lungs.

To further explore the properties of MLN lymphoblasta, the influence of the mouse estrous cycle on MLN lymphoblast localization in the cervix and vagina was investigated. Compared to proestrus and estrus, a 2-fold reduction in the number of MLN lymphoblasts localizing in the diestral cervix and vagina was observed. Detection of the immunoglobulin isotype of these cells suggested that this reduction was restricted to the IgA plasmacyte progenitor population, i.e., the major B-lymphocyte subpopulation entering these sites. No significant changes in B-lymphoblast subpopulation lodging in the small intestine were observed over the course of the estrous cycle. Moreover, although the small intestine more than doubled in wet weight by late gestation, this increased quantity of gut tissue did not appear to compete for a finite number of donor MLN lymphoblasts. It was concluded that changes in the sex hormone status of mice may influence selective localization of MLN lymphoblasts in sex hormone target tissues.

Since subpopulations of cells can often be separated from each other on the basis of cell size, some preliminary studies were done to purify, on the basis of size, subpopulations of mouse MLN lyphoblasts. These results indicated that the labelled cells being transferred were all large in size, likely lymphoblasts, and that it was possible to use this technique to obtain donor cell populations highly enriched in the proportion of labelled cells. Some evidence was obtained to suggest that the MLN contained a minor population of lymphoblasta with a propensity to localize in the spleen.

To examine the possibility that some lymphocytes in the gut mucosa may themselves have a predisposition to localize in other mucosal tissues (assuming that they were able to migrate), lymphocytes were mechanically prepared from the lamina propria of the guinea pig small intestine. A subpopulation of these cells incorporated ¹²⁵I-deoxyuridine and localized (within 24 h after adoptive transfer) in the gut mucosa in a manner similar to transferred MLN lymphoblasts and different from either PLN or Peyer's patch lymphoblasts. It was concluded that a portion of the lymphocytes seen in the gut mucosa were similar in migration characteristics to cells found in the MLN.

The results of these studies support the concept of a common mucosal immunologic system in which different mucosal surfaces are linked by migrating IgA plasmacyte precursors originating primarily in the lymphoid tissue associated with the intestinal and respiratory tracts. s of these studies support the concept of a which different mucosal surfaces migrating IgA plasmacyte precursors originating primarily in the lymphoid tissue associated with the intestinal and respiratory tracts.

abstract: Doctor of Philosophy (PhD)


title: Thermal Degradation of Polystyrene

contributor:
Hamielec, A.E.
Chemical Engineering

subject:
Chemical Engineering
Chemical Engineering

abstract: In this study uninhibited styrene, degassed under high vacuum (10ˉ⁶ mm Hg), was thermally polymerized in bulk of 10ˉ⁶ mm Hg to almost complete conversion. The samples so obtained were thermally degraded under the same high vacuum conditions at temperatures ranging between 270°C and 340°C for different time intervals over the whole range of degradation. The breakdown of the polymer, through changes in number, weight average molecular weights, polydispersity and molecular weight distribution, was investigated using gel permeation chromatography. A mechanism of degradation was sought, and the breakdown explained by a combined process of deploymerization and chain scission. Scission constants were determined and compared with the constants, obtained from a polystyrene having much larger molecular weights.

abstract: Master of Engineering (ME)


title: The magnetic properties of the rare earth titanium oxides RTiO(3); R = terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium

contributor:
Greendan, J.E.
Collins, M.F.
Chemical Physics

subject:
chemical physics
Biological and Chemical Physics
Biological and Chemical Physics

abstract: The magnetic properties of the heavy rare earth titanium oxides RTiO₃, R=Tb, Dy, Ho, Er, Tm, Yb and Lu, have been investigated. The RTiO₃ develop a spontaneous magnetization below critical temperatures ranging from 28 K to 64 K. Both the rare earth and titanium moments order at the same temperature. The field dependence of the magnetization at 4.2K indicates that the magnetocrystalline anisotropy is very large. The paramagnetic susceptibility of the materials formed with R=Tb-Tm is analyzed with molecular field theory to obtain the molecular field coupling constants λTi-Ti, λR-Ti and λR-R. The magnetic structures are determined for RTiO₃, R=Tb-Tm with the technique of neutron diffraction. The erbium and thulium moments form a ferromagnetic array along the orthorhombic c cxis and the terbium, dysprosium and holmium moments have both ferromagnetic and antiferromagnetic components in the ab plane, giving rise to a canted structure. The titanium moments are in a ferromagnetic array which is directed antiparallel to the ferromagnetic component of the rare earth moment. The preferred direction of the rare earth magnetization with respect to the orthorhombic c axis is discussed in terms of the interaction between 4f electrons on the rare earth and the crystalline environment. Calculations are presented which support this hypothesis.

abstract: Doctor of Philosophy (PhD)


title: Process Dissociations of Conscious and Unconscious Perception

contributor:
Jacoby, Larry L.
Psychology

subject: Psychology Psychology

abstract: Conscious perception is substantially overestimated when standard measurement techniques are used. That overestimation has contributed to the controversial nature of studies of unconscious perception. I employed a process-dissociation procedure (Jacoby, 1991) for separately estimating the contribution of conscious and unconscious perception to performance of a stem-completion task. Unambiguous evidence for unconscious perception was obtained in seven experiments. Debner and Jacoby (1994, Experiment 1) showed that decreasing the duration of a briefly presented word diminished the contribution of both conscious and unconscious perception. In Experiments 2, 3 and 4, Debner and Jacoby found that dividing attention reduced the contribution of conscious perception while leaving that of unconscious perception unchanged. Debner (submitted) used the same stem-completion task to show that estimates of unconscious perception could also be affected. In one set of experiments (Experiments 1a and 1b), increasing the interstimulus interval between the briefly presented word and the test of stem completion decreased the contribution of unconscious perception to performance but left that of conscious perception intact. Experiment 2 revealed that a manipulation of visual similarity produced a similar process dissociation. Discussion focuses on the measurement of awareness, the relationship between perception and memory, and the possible episodic nature of conscious and unconscious perceptual processes.

abstract: Doctor of Philosophy (PhD)


title: A Search for the Oblique Effect in Young Infants

contributor:
Maurer, D.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
For a wide variety of visual tasks, subjects perform more poorly when stimuli are oriented obliquely than when they are oriented vertically or horizontally. It is generally believed that this 'oblique effect' has two manifestations. One is meridional anisotrophy, i.e., lower acuity for obliquely oriented stimuli than for vertical or horizontal stimuli. The second is poor oblique discrimination; i.e., greater difficulty discriminating between mirror-image oblique stimuli than between vertical and horizontal ones, even when the stimuli are above the threshold of acuity. This thesis explores whether these two phenomena are in fact both manifestations of the same effect.

Chapter One provides a detailed survey of studies showing meridional anisotrophy and considers the nature of its etiology and development. Chapter Two provides a review of the existing literature on the discrimination problem as evidenced in young children. The author argues that while meridional anisotrophy and poor oblique discrimination by young children appear to be related phenomena, it is possible that both are not manifestations of the same effect. The author tested this possibility by comparing the developmental course of poor oblique discrimination with the know developmental course of meridional anisotrophy.

Chapters Three through Six present four experiments in which the author tested young infants' ability to discriminate between mirror-image oblique stripes with their ability to discriminate between "vertical-and horizontal ones, with the stripes above the threshold of acuity. In one experiment six week olds were tested; in the other three, 17-18 week old infants were tested using different variants of the habituation procedure.

The major finding of the research is that neither 6 week nor 17-18 week old infants, both of whom are known to show meridional ranisotrophy, show evidence that a mirror-image oblique discrimination is more difficult than a discrimination between a vertical and horizontal. Furthermore, modification of the testing procedure, so that it more closely mimics a task in which children show difficulty discriminating mirror-image oblique lines, does not appear to affect 17-18 week olds discrimination performance.

In the final chapter, the author discusses the implications of the research findings. The author concludes that since infants known to show meridional anisotrophy do not show poor oblique discrimination, then it is probable that these two phenomena are not both manifestations of the same effect nor do they appear to be generated by the same underlying mechanism. The author also discusses the implications of the research findings for two cognitive theories which have been advanced to explain how children process obliquely oriented stimuli.

abstract: Doctor of Philosophy (PhD)


title: Effects of Training and Immobilization Upon NeuromuscuIar Function in Man

contributor:
McComas, A. J.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
The effects of strength training and immobilization upon neuromuscular function in man were investigated. The selected measures of neuromuscular function were voluntary strength and a number of electrophysiological measurements, including motor unit counts, motor nerve conduction velocity, reflex potentiation, and the contractile properties of isometric twitch contractions.

Three kinds of experiments were conducted. First, subjects participated in training and immobilization experiments. Training, which consisted of maximal isometric and concentric muscle contractions and weight lifting, was performed three times per week over a period of 10-20 weeks. Relative disuse of selected muscle groups was achieved by immobilizing the elbow, wrist and thumb joints in a cast for 3-6 weeks. Second, measurements were made in selected groups of athletes (weight lifters, gymnasts, cyclists, sprinters, cross country skiers) to provide cases of long term training. Third, measurements were made on control subjects, whose results were compared to those of the athletes.

Training resulted in an increase in voluntary strength. As cases of long term training, voluntary strength was enhanced in weight lifters and cyclists. Immobilization resulted in a decrease in voluntary strength.

Training had no effect upon motor unit counts and the motor unit counts in the weight lifters were normal; however, the gymnasts exhibited reduced motor unit counts in distal but not proximal muscles. It was hypothesized that injury to the nerves at the wrist and ankles was responsible for the reduced motor unit counts in the gymnasts. Immobilization had no effect upon motor unit counts.

Neither training nor immobilization caused a change in motor nerve conduction velocity in relation to the control condition; however, in one group of subjects, there was a small though significant difference between the greater post training and the lesser post immobilization values. Nerve conduction velocity was greater in weight lifters and gymnasts than in controls.

Reflex potentiation increased following training, providing new evidence in support of the hypothesis that adaptation occurs within the nervous system in response to training. In agreement with the above finding was the enhanced reflex potentiation in the weight lifters. Immobilization caused a decrease in reflex potentiation, indicating that the nervous system is involved in the adaptation to relative disuse as well as to training.

Muscle (triceps surac) twitch tension and contraction time were greater in weight lifters than in controls. In this same muscle, short term training resulted in an increase in twitch half relaxation-time. These findings represent the first report of a slowing of muscle contraction in response to training.

In conclusion, the present investigation provided new evidence indicating adaptation within both the muscle and the nervous system in response to strength training and within the nervous system in response to immobilization.

abstract: Doctor of Philosophy (PhD)


title: Ripening processes and meltwater movement in Arctic snowpacks

contributor:
Woo, M.K.
Biology

subject: Biology Biology

abstract: This is a study of the processes controlling snowpack ripening and the movement of meltwater through wet snowpacks. Measurements made in the Canadian High Arctic during the 1979, 1980, and 1981 snowmelt periods, included premelt stratigraphy, surface energy balance, physical changes in snowpack properties during melt, snow and soil temperatures, and water movement within the pack. Field observations and computer modelling demonstrated an interdependence of finger flow at the wetting front and ice layer growth at premelt snow horizons. Ice layers grow rapidly in cold snowpacks, slowing the finger wetting front advance and releasing considerable latent heat which warms the underlying snow and toil. Since the ground is frozen when water reaches the ground surface, the meltwater refreezes at the snowpack base. The growth of this basal ice layer limits the amount of water available for daily runoff and extends the melt period, a phenomenon which is typical of cold arctic snowpacks. A redistribution of flow within the snowpack, concentrating flow in certain areas and diminishing it in others, is due to variations in ice layer properties, and not flow instabilities or vertical flow channels. The re sult is a spread of the rising limb of the melt wave at depth and a decrease of the peak flow. Results from a multiple flow path model, suggest that flow variability is similar in snowpacks from different environments. This indicates that the model is applicable to snowpacks in a wide range of environments.

abstract: Doctor of Philosophy (PhD)


title: The State, Industrialisation and Class Formations in India: A Neo-Marxist Perspective on Colonialism, Underdevolpment and Development

contributor:
Sheriff, P.
Sociology

subject: Sociology Sociology

abstract: This thesis is a theoretical and empirical analysis of the state and its relationship to the evolution of the social economy. The study is based on a concrete examination of a particular social formation, namely that of India. The thesis argues that the state in India, because of the nature of the mode of production, has been able to play an autonomous role vis-a-vis the social classes. This contention is contrary to the traditional Marxist class theory of the state which maintains the state is always a means of class hegemony, except in transitional social formations. It has also been argued that once the state attains a definite form, it reacts on the evolution of a social formation and, in turn, is determined by its changing nature. On the basis of a concrete study of the evolution of the social formation of India, it is shown that the autonomy of the state which resulted from the Asiatic mode of production obstructed India's transition to capitalism, and thus undermined its economic development and led to colonisation. It is then explained how continuation of the state's autonomy vis-a-vis the indigenous social classes during the colonial period resulted from a social formation which was partIy Asiatic partly feudaI and partly capitalist, as well as from the colonial state's subservience to the metropolitan bourgeoisie. This conjuncture enabled the state to make considerable resource bourgeoisie. This conjuncture enabled the state to make considerable resource transfers from India to the metropolitan centres, thus leading to India's underdevelopment and low labour productivity. The subsequent attempt on the part of the post-independent state in India to maintain its autonomy, which is derived from much the same social formation inherited from the colonial period, has resulted in the extensive state control measures of the private corporate sector. This attempt has also given rise to the concentration of basic industries in the hands of the state, the sustenance and encouragement of the artisan an petty industries as a counterweight to the private corporate industries and the failure of the bourgeoisie to transform agriculture into a capitalist sector. Finally, it is argued that these measures, in turn, have led to a skewed development of the economy in which the condition of the masses and direct producers has gradually deteriorated, and consequently the economy Is threatened with an uncertain future.

abstract: Doctor of Philosophy (PhD)


title: Induced Technological Change in United States Manufacturing Industries

contributor:
Butterfield, D.W.
Economics / Economic Policy

subject: Economics Economics

abstract: Recently, technological change has received increasing attention from researchers. One of the many questions addressed has been concerned with the forces that govern the rate of inventive activity and. hence technological change. Two distinct strands of argument have appeared in historical succession. Broadly speaking, these can be distinguished as pertaining to either the supply of or demand for inventive activity as the major determinant of technological change. First, following the historical progression, was the argument that the supply of inventive activity (the development of basic science and occasional appearance of inventive genius) was the crucial factor in determining its rate, in which case inventive activity was treated as exogenous to the economic system. Recently, however, the argument seems to have shifted in favour of the primacy of the demand for inventive activity. The proponents of this argument suggest that inventive activity is governed by market forces, which would make it an endogenously determined variable. Demand for inventive activity is a derived demand. Although, in this respect, the role of final product demand has been stressed, there is yet no consensus as to what other variables may affect the derived demand for inventive activity. Which of the two above mentioned positions accurately represents the generation of inventive activity has implications for policy designed to influence technological change. The present study is an attempt to explore the role of supply and demand forces in determining the rate of inventive activity. Empirical investigation, based on a simple model of induced technological change, is carried out for 11 manufacturing industries in the United States. The evidence indicates that demand for inventive activity is a significant determinant of inventive activity in the industries studied. The demand side variables (output, relative factor prices, and the state of technology) performed fairly well in explaining R&D expenditures (as an index of inventive activity). Unfortunately, the evidence about the effect of the supply of inventive activity (represented by the state of knowledge in the respective industries) remains inconclusive. However, the results in conjunction with the individual industry characteristics indicate that the effect of supply side of inventive activity is much more complex than assumed in the present study. This leads to certain suggestions for further research which will take the supply side of inventive activity into consideration more effectively.

abstract: Doctor of Philosophy (PhD)


title: Experimental Analysis of the Embryonic Origin and Development of the Pectoralis Major Muscle of the Chicken

contributor:
Rathbone, M.P.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
The purpose of the studies reported in this thesis was to obtain data concerning the embryonic origin and formation of the pectoralis major muscle of the chicken. This muscle is used extensively in studies on muscle development because it is large; readily available, and is composed almost entirely of one muscle fiber type. Moreover, it is the largest muscle to be affected by hereditary muscular dystrophy in the line of chickens afflicted with this disease. Information concerning its embryonic origin could be used for in vivo studies on the early development of both normal and dystrophic muscles.

Previous investigations into the embryonic origin od skeletal muscle in several classes of vertebrates have resulted in controversy. Some investigators have concluded that all skeletal muscles arise from the myotomal layer of the somites. Others have cited evidence to show that some muscles, including the pectoralis major muscle of the chick, are derived from the somatopleuric mesoderm adjacent to the somites.

In the present investigation, interspecific chimaeras have been used to study the problem. Whole somites, somite halves, or limb-buds were grafted from quail to chick embryos between 2 and 3 days in ovo. After further development, the chimaeras were fixed, embedded in paraffin, sectioned, and stained using the Feulgen reaction for chromatin. This procedure permitted the identification of those structures that were derived from the grafted quail tissue.

The observations in this study have led to the following conclusions:

The pectoralis major muscle arises from the dorsal halves of somites 16-21 of the 2-day in ovo chick embryo. These somites also give rise to all other wing and wing-associated muscles of the shoulder and thorax. Each somite plays a specific role in the development of these muscles. The cells that ultimately form the pectoralis and other brachial muscles migrate from the somites into the lateral mesoderm between 2 and 2.5 days in ovo. The myotomal layers of the somites do not appear until 2.5 days in ovo and do not contribute to the formation of the brachial muscles.

abstract: Doctor of Philosophy (PhD)


title: Substructural Studies at Large Strains in Aluminum

contributor:
Embury, J.D.
Metallurgy and Materials Science

abstract:
The nature of the dislocation substructure developed at large strains in single crystals of aluminum has been studied. The detailed characteristics of the substructure have been studied as functions of (a) strain, up to compressive strains of 1.0 and (b) crystal orientation. The crystal orientations have been selected to substructure developed during deformation.

The Bishop-Hill and yield subsurface analyses have been adopted to predict the operative slip systems. Applicability of these methods to large strain deformation studies has been discussed.

Results of the present study emphasize the influence exerted by crystal orientation via the nature of operative slip systems and the extent of homogeneity of slip on the extent of dynamic recovery and the resulting dislocation substructure. Development of high angle boundaries in the as-deformed condition in crystals deformed to large strains, is associated with inhomogeneity of slip. Origin of these high angle boundaries during deformation and their role in subsequent recrystallization process have been discussed.

abstract: Doctor of Philosophy (PhD)


title: Comparative Study of the Muscle Layers of The Rabbit Duodenum

contributor:
Daniel, E.E.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
The studies presented in this thesis are the first attempts to compare in a comprehensive manner the basic electrical and mechanical properties of the two muscle layers of the small intestine of the rabbit, a species that showed electrical control activity (ECA). The activities of the two muscle layers were distinctly different. Cells in the longitudinal muscle layer (LM) were spontaneously active with action potentials occurring on every control potential (CP). Similarly, muscle strips dissected along the long axis of LM (LS) contracted spontaneously at the same frequencies as the ECA. Cells of the circular muscle layer (CM) usually did not exhibit spontaneous spiking activity although ECA was also present.

The characteristics of the ECA of the two muscle layers from the same muscle strips were similar in terms of amplitude, frequency, and their response to temperature change and external electrical stimuli. How the ECAs of the two muscle layers interact was investigated in light of the hypothesis that LM is the site of origin of ECA and that the ECA in CM is the result of electrotonic spread from LM (Bortoff, 1961, 1976; Connor, Kreulen, Prosser & Weigel, 1977). This hypothesis was tested directly in this study by measuring electrotonic coupling between the two muscle layers. It was found the there was little electrotonic interaction between muscle layers. Therefore, the result of this study is not consistent with the existing model in regard to the origin of the ECA.

Study of the control of muscle function by the intrinsic nerves also showed drastic differences between the two muscle layers. LM was innervate by cholinergic excitatory nerves and possibly by an inhibitory neural system. In CM, three types of neural excitatory events were identified in addition to the powerful non-adrenergic inhibitory nerves. Besides the familiar cholinergic excitatory nerves, a tetrodotoxin-resistant component and an excitatory response that emerged only after prolonged repetitive stimulation was also observed. The neurotransmitters for these two excitatory neural systems remain to be identified.

The results of this study indicate that the properties of the two muscle layers of the small intestine are very different. Nonetheless, normal physiological function of the intestine requires good coordination of the two muscle layers. The exact role of the individual layers in motility is not well defined. How these two muscle layers each with its separate neural, hormonal and local control mechanisms interact to produce the final intestinal motility pattern will be a challenging problem in the future.

abstract: Doctor of Philosophy (PhD)


title: Bench Scale Leading Studies on Uranium Mill Tailings

contributor:
Baird, Malcolm H.I.
Banerjee, S.
Chemical Engineering

abstract:
Uranium-bearing ore is crushed and leached to extract uranium in an ore processing plant. However, the decay products of uranium are discarded as wastes or tailings from the plant. One such decay product is Ra²²⁶, which is quite toxic and mobile. It remains dispersed with the tailings and spreads into air and potable waters from the tailing areas due to natural forces and decay to gaseous Rn²²².

In this work, bench scale leaching of the uranium mill tailings was done with a view to extract Ra²²⁶ into the liquid phase. A gamma counting technique for determination of Ra²²⁶ concentrations in solid and liquid samples was also developed. Details of sample preparation, ingrowth, and calibration are discussed. For extraction of radium, several extractants such as water and solutions of CaCl₂, EDTA, DTPA and HNO₃ were used. Effects of solid to liquid ratio and time of contact on the extraction of Ra²²⁶ were studied for these extractants. In some cases, effects of temperature, concentration of extractant and multiple cross current contacting were also studied. The results of various leaching experiments are interpreted.

The main results show that equilibrium distribution of radium between the extractants and tailings was attained rapidly. In all experiments, a fraction of radium was "unextractable", i.e., all operating lines had an intercept when extrapolated to zero solid to liquid ratio. In general, the operating lines had a relatively small slope indicating that high solid to liquid ratio could be used without significantly degrading extraction.

abstract: Master of Engineering (ME)