John Chrysostom's understanding of the Eucharist in its relation to the Christian life
- Authors: Amos, Charles Harry
- Date: 1988
- Subjects: John Chrysostom, Saint, d. 407 , Lord's Supper , Lord's Supper -- Biblical teaching
- Language: English
- Type: Thesis , Masters , MTh
- Identifier: vital:1217 , http://hdl.handle.net/10962/d1001547
- Description: The aim of this thesis is to reveal the intimate relationship between John Chrysostom's Eucharistic theology and the christian life, and that at the Eucharist Man's true being is demonstrated. It investigates Chrysostom's exegetical and oratorical method in order to ascertain how he approached a text and how he delivered his understanding of it. He is a representative of the Antiochene School of Exegesis and his fame as a preacher was a result not so much of his oratorical construction, but of the underlying spiritual unity within the oration. The purpose of all his preaching and exegesis was to evoke a moral response from his hearers. In the consecration of the elements, Chrysostcm displayed a remarkable openness to the varying traditions. He saw reciting the words of institution and invoking the Spirit as effecting consecration. Not only this, but also the moral life of the congregation played its part in effecting consecration. Once the elements had been consecrated, Christ was sacrificed, symbolically and literally, not again but in memory (Greek letters) of the Passion, which thereby becomes a present reality. In Chrysostom's understanding of the real presence he displays yet again an openness to the traditions. Christ is both present symbolically through the elements and literally through the transformation of the elements. The real presence demanded of the communicant a high degree of morality. To approach the Table on which Christ lay demanded a life of virtue, not only from the individual communicant but from the whole community. Those who partook unworthily imitated Judas and shared his fate. The community had to approach the Table in unity. At the Table, however, the community received its unity from Christ, the community became the body of Christ. Through participation and becoming the body of Christ, the community was united with the Godhead . Schism, therefore, was a very serious sin for it tore the body of Christ apart. For Chrysostom, Christ was also present in and intimately united with the poor. The church had to be able to be aware of Christ's presence in the poor and be responsible toward Him. In giving to the poor, the communiicant acknowledged that he/she had received at the Table and also received his/her salvation from Christ through the poor. The whole Eucharistic feast not only fed the christian with spiritual food, but called the communicant away from gross materialism to a life-giving dependance on God. It called the communicant to give to others as he/she had received from Christ.
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- Date Issued: 1988
Structural studies on some capsular antigens from escherichia coli and klebsiella
- Authors: Anderson, Andrew Nixon
- Date: 1988
- Subjects: Escherichia , Klebsiella , Antigens
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3730 , http://hdl.handle.net/10962/d1001469
- Description: A review of the structural studies of bacterial capsular polysaccharides (K-antigens) from Escherichia coli and Klebsiella, and of the trends in modern chemical and instrumental techniques available for the analysis of carbohydrate material is presented. The structural elucidations of the capsular polysaccharides from E. coli K37 and K55, and Klebsiella K39 are reported with comments on the novelty and possible immunological significance of the structures. The usefulness of the bacteriophage degradation technique has been emphasized using the polysaccharides from E. coli K55, and Klebsiella K30 and K39 to demonstrate the scope of the reaction
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- Date Issued: 1988
An investigation into the role that knowledge of the nature of mathematics and other factors play in determining motivation for further study of mathematics after std 7 in selected provincial secondary schools
- Authors: Arguile, David Ian
- Date: 1988
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1352 , http://hdl.handle.net/10962/d1001418
- Description: This study involves an investigation into reasons why pupils continue with mathematics after Std 7. The sample, consisting of Std 8 and Std 10 mathematics pupils at six academic, English-medium high schools in Port Elizabeth, had to complete a short questionnaire during the third term of 1985. It was found that most pupils continue with mathematics because of requirements for certain post-matric courses, to improve their career options and for other reasons classified in this investigation as "extrinsic", i.e. reasons that are not directly related to the nature of mathematics. An attempt is made to determine the extent of the pupils' knowledge of the nature of mathematics. Questions relating to the nature of mathematics are poorly answered by almost all of the pupils, thereby suggesting that this aspect of mathematics is sadly neglected in mathematics courses. The suggestion is made that this lack of knowledge of the nature of mathematics is linked to pupils' decisions to continue with the subject. The conclusion is drawn that unless more attention is given to conveying to pupils something of the nature of mathematics, there will be an increasing proportion of pupils who choose to continue with mathematics for the "wrong" reasons. This, in turn, has possible negative implications for mathematics education in general. Attention is also paid to differences re the above in respect of groupings based on standard, mathematical grade, sex, mathematical achievement and type of schooling. Although no conclusive findings are made other than with regard to specific questions, enough evidence of differences in certain of the groupings is produced to warrant further investigation
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- Date Issued: 1988
The Port Elizabeth disturbances of October, 1920
- Authors: Baines, Gary F, 1955-
- Date: 1988
- Subjects: Black people -- South Africa -- Port Elizabeth -- Social conditions , Police shootings -- South Africa -- Port Elizabeth , Labor movement -- South Africa -- Port Elizabeth -- History
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2529 , http://hdl.handle.net/10962/d1001858
- Description: Chapter one suggests thet trade and merchant capital, which were crucial to Port Elizabeth's economic development during the nineteenth century, was subsumed by the rise of manufactures and industrial capital after the First World War. Industrial expansion was cut short by the post-war recession, which caused un- and underemployment. The black worker, who experienced a severe loss in real earnings on account of the increased cost of living, became involved in a struggle with employers for wage increases. Chapter two shows how the policy of segregation was applied in Port Elizabeth, which meant that the workers were subjected to an increasing degree of control and regulation of their daily lives. The conditions of reproduction in the black townships fostered inter-racial and cross-class mobilisation which culminated in the formation of a general labour union, the Port Elizabeth Industrial and Commercial Workers' Union (PEICWU). Chapter three will suggest links between the tradition in Port Elizabeth of worker resistance and the unionisation of black workers in the post-war period. Thus, the first three chapters attempt to provide a historical perspective for analysing the underlying causes of the 1920 Port Elizabeth disturbances. The immediate cause of the disturbances was the arrest of the Union leader, Masabalala, after he called for a general strike. Chapter four will show how the intervention of the local authorities provoked a spontaneous act of defiance on the part of Union members. A demonstration outside the Baakens Street Police Station to demand the release of Masabalala, precipitated the tragic shootings of 23 October 1920. The repressive violence which left 22 dead (with two further deaths resulting indirectly from the incident) was unprecedented in South African history. The resolution of the crisis brought the workers no nearer to obtaining a reasonable settlement of the wage issue. If anything, the resolve of employers to deny wage demands was hardened by the actions of the local authorities, who attributed the disturbances to ' agitation '. Such thinly-disguised justifications of the shootings by the dominant classes, however, provoked recriminations from other quarters. Chapter five examines the legal and political ramifications of the Port Elizabeth shootings. The circumstances of the shootings prompted the Smuts Government to appoint a Commission of Enquiry in the face of public pressure. The Commission found that the Police and vigilantes were largely to blame for the high death toll. But the Government's 'whitewash' of the findings could not absolve the Police from culpability entirely, nor could it sidestep its own responsibility and liability to victims of the shootings. Finally, in Chapter six, an attempt will be made to assess the long term impact of the shootings on the PElCU and the black labour movement in Port Elizabeth generally. The outcome of the episode was a victory for employers, which dealt a body blow to worker organisation which only became resurgent in the 1950s.
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- Date Issued: 1988
The development of a concept of psychological well-being
- Authors: Bar-On, Reuven
- Date: 1988
- Subjects: Mental health -- Psychological aspects Personality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2928 , http://hdl.handle.net/10962/d1002437
- Description: This thesis focuses on the development of an operational and theoretically eclectic concept of psychological well-being. A comprehensive research strategy was employed to examine various personality factors thought to be components of psychological health (i.e., the basis of the proposed concept). The general approach involved four major phases: (1) the clustering of various variables and identification of underlying key factors purported to be related to psychological health based on the writer's clinical experience and review of the mental health literature, (2) the formulation of an ~ priori concept of psychological well-being based on the operational definition of those factors, (3) the construction of an inventory designed to examine the proposed concept, and (4) the interpretation of the results and their implications for the development of the overall concept based on the examination of the factorial structure, validity and reliability of the inventory. The"a posteriori concept" evolved out of this process. The results of the present study indicate that the most valid and reliable factorial components of psychological well-being are self regard,interpersonal relationship, independence, problem-solving, assertiveness,reality testing, stress tolerance, self-actualization and happiness; social responsibility and flexibility emerged as questionable components of the a posteriori concept. The inventory which was designed to study the concept was successful in significantly differentiating various levels of psychological health. This way of conceptualizing and assessing psychological well-being has potential applicability for mental health practitioners and researchers.
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- Date Issued: 1988
An analysis of the structural use of music, song and dance in certain novels by West African writers in relation to concepts of time
- Authors: Baxter, Marion
- Date: 1988
- Subjects: Music and literature
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2174 , http://hdl.handle.net/10962/d1001825
- Description: The topic of this thesis is time in the West African novel in English and French, and the key approach is that West African time is readily grasped through a study of West African music. Though Western time is not exclusively or only linear, mechanical and exploitative, and African time not exclusively cyclic, synchronic and experiential, yet there is a characteristically African view of time and preferred modes of its employment in West African fiction. The novelists considered here wrote in European languages, yet each was a member of a specific cultural group and concerned to portray the aesthetics of his inheritance, an important aspect of which is the predominance of repetitive formulae, both in music and in oral literature. The Introduction offers an historical survey of some of the main notions of time that have been manifest in the West, and compares them with notions of African time. Chapter One examines the structural use of rhythm and repetition in the novels of Camara Laye. Chapter Two discusses the griot and other traditions of oral literature in the novels of Ayi Kwei Armah and Yambo Ouologuem, novels which are concerned with the griot 's continuing role in the creation and dissemination of historical perspective. Chapter Three analyses Chinua Achebe 's portrayal of the values of pre-colonial life in Igbo society where the role of music is to limit behaviour through the structures of ritual which thus create static/cyclic time. Chapter Four describes the syncretic art-form, 'highlife', as used by novelists such as Wole Soyinka, which, because it is transitory and always changing, underscores the ironies of modern city life. The thesis concludes that the authors discussed above are aware that music, because it is predominantly social in Africa, is a powerful medium for achieving a healing synthesis between the traditional past when communalistic values were binding, and the urban-orientated present with its insistence on individuation and material enrichment.
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- Date Issued: 1988
Cleavage of the precursor coat protein of black beetle virus strain w17 in rabbit reticulocyte lysate
- Authors: Blackhurst, Diane Mary
- Date: 1988
- Subjects: Beetles , Insects -- Viruses
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3880 , http://hdl.handle.net/10962/d1001614
- Description: Black beetle virus (BBV) is a bipartite single-stranded RNA virus belonging to the family Nodaviridae. Its host range has been found to be limited to insects. RNA 1, the larger of the two RNA molecules, with a MW of 1,15 x 10⁶ and the smaller RNA 2 with a MW of 0,46 x 10⁶, are both packaged in the same virus particle. The two RNA molecules are translated separately, with RNA 1 coding for protein A of MW 105 x 10³ and RNA 2 coding for protein α of MW 47 x 10³. Protein α is the major capsid protein precursor, which during in vivo maturation is cleaved to form the coat protein β of MW 43 x 10³, and protein γ of MW 5 x 10³. Cell-free translation of BBV (strain W17) mRNA was carried out in rabbit reticulocyte lysates. Protein α was detectable between 0 and 30 minutes after RNA addition. A protein 'β', which was found to co-electrophorese on polyacrylamide gels with authentic β and which was immunoprecipitated by anti-BBV antiserum, was detectable after 30 minutes. Results of this work show that the formation of 'β' could be prevented by the addition of RNase to the lysate, indicating that intact RNA is necessary for α to β cleavage. Arresting protein synthesis by the addition of cycloheximide to the lysate mix did not inhibit the cleavage. The formation of β could also be prevented by cooling the lysate mix to 1°C. Cleavage of α to β still occurred when RNA 2, without the presence of RNA 1, was translated. Therefore the cleavage is not dependent on a translation product of RNA 1. Sedimentation of lysate on sucrose density gradients showed that α to β cleavage was not accompanied by assembly of BBV RNA and protein lnto a viral substructure as has been shown to occur with some viruses, for example certain picornaviruses. Serial dilution of lysate containing α showed that the level of β decreased with increasing dilution, indicating that the cleavage is not mediated by autocatalysis, but by some other unknown factor. Although much work has been carried out on black beetle virus, no work has been published to date concerning α to β cleavage as an indication of assembly in rabbit reticulocyte lysates. Results of these cell-free translation experiments thus indicate that BBV coat protein precursor α, in association with its messenger RNA 2, undergoes a maturation cleavage in the lysate to produce BBV coat protein β. In addition, this cleavage seems to occur without assembly into any intermediate viral structure
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- Date Issued: 1988
Petrology and geochemistry of the lower group chromitites and host rocks on the farm Zandspruit 168 JP, Western Bushveld Complex
- Authors: Botha, Michael James
- Date: 1988
- Subjects: Petrology -- Africa, Southern , Geochemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4905 , http://hdl.handle.net/10962/d1001565
- Description: The eight Lower Group chromitite layers of the Ruighoek Pyroxenite in the area west of the Pilanesberg (LGl - LG7), on the farm Zandspruit 168 JP, were sampled in borehole cores drilled through the succession. The stratigraphic succession faIls within Cameron's (980) units B to E of the Critical Zone. The lowermost layer of the Lower Group, the LG 1 chromitite, is located some 440 metres below the MG 2 (Middle Group) chromitite layer, above which the first appearance of cumulus plagioclase in the Complex is seen. By convention, this horizon is designated the top of the Ruighoek Pyroxenite in the Western Bushveld Complex. Homogeneous units of chromite-bearing orthopyroxenite (bronzitite), exhibiting inconspicuous layering defined in terms of variations in orthopyroxene grain-size host all but one of the Lower Group layers; the LG 4 chromitite layer is exposed within an olivine-rich subunit 23 metres in thickness (C₃ subunit). The cumulative thickness of chromitite is 2,92 metres or 0,8 per cent of the studied section, which is 381 metres in thickness. Minimum and maximum thicknesses of the LGl - LG7 layers exposed in drill core are 17 and 81 centimetres, respectively, with minor chromitite layers ranging between 2 and 5 centimetres in thickness. Weighted mean Cr₂0₃ contents of units B to E vary between 1,17 and 3,22 per cent, with the latter estimate representative of the D₂ subunit which hosts the LG 6 chromitite layer. The LG 6 is correlated with the Steelpoort layer of the Eastern Bushveld Complex, and varies between 76 and 81 centimetres in thickness under a large portion of the farm Zandspruit. An undisturbed succession striking N15°E and dipping 12 - 15°E is depicted within the studied area, which is bounded on the eastern side by the north-striking Frank fault. Major folding of the layered succession is evident to the north of the area, where the layering adjacent to the trace of the fault dips 35° to the southwest. Particular attention is paid in the present study to (a) the nature of chromitite layers and their host rocks, (b) the contrast between the mineral chemistry of weakly disseminated chromite and grains within massive ore layers, (c) concentrations of Cr, V, Ni, Co, Sc and Ti in orthopyroxene in relation to stratigraphic height, and levels of Sr, Ba and Zr associated with hypothetically pure, intercumulus plagioclase feldspar, and (d) possible mechanisms which induce crystallization of chromitite layers containing 50 per cent Cr₂0₃ from magma with a Cr content of less than 1 000 ppm. Electron microprobe studies of chromite in relation to mineralogical and textural environment clearly reveal that (a) the proportions of Cr and Al cations are linked to paragenesis: higher Al/Cr ratios characterize olivine-bearing domains, whereas grains intergrown with plagioclase feldspar exhibit low AI/Cr ratios, and (b) Al contents rise with a decline in Mg/(Mg + Fe²⁺) from high values to a value of 0,450, then decrease with a further decline in Mg/(Mg + Fe²⁺). The paragenetically later trend is emphasized in a large population of chromite grains which escaped early encapsulation in orthopyroxene crystals and continued to grow in the environment of intercumulus plagioclase. Within-and between-sample compositional variation of grains in silicate-rich domains is modelled in terms of in situ growth increments, diffusive homogenization of zonal structures, and residence time within interstitial melt. Fractionation trends, as measured by Mg/(Mg + Fe²⁺) ratios in whole-rock and/or microprobe studies of orthopyroxene, are reversed in relation to stratigraphic height towards the top of the B unit and in the overlying C unit. These data are supported, for example, by lower vanadium contents and higher Ni/Sc ratios in hypothetically pure orthopyroxene. Small olivine crystals in chromite-rich domains are enriched in Ni relative to coarse-grained olivine in adjacent dunite: a feature attributed to early isolation of primocrysts from magma in the former case, and in situ equilibration between olivine crystals and Ni-depleted residual melt in the latter case . Similarly, rising Ni contents and Mg/(Mg + Fe²⁺) ratios of orthopyroxene with increasing stratigraphic height in the footwall of the LG 6 chromitite layer, linked to a progressive decline in orthopyroxene grain-size, are effects which may arise out of early separation of interstitial melt from orthopyroxene cumulates. A model is thus proposed which (a) links the thickness of chromitite layers to the vertical separation between successive layers or the thickness of fine-grained orthopyroxenite in the footwall, (b) ascribes copious nucleation of chromite to liquid mixing of this footwall derived, Cr - depleted contaminant with influxes of hot, primitive magma, and (c) tenders the notion that the present modal proportion of mesostasis in the footwall of a chromitite layer serves as a reciprocal measure of the volume of fractionated exudate
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- Date Issued: 1988
Sequence in the mathematics syllabus : an investigation of the Senior Secondary Mathematics Syllabus (July 1984) of the Cape Education Department attempting to reconcile the demands of the strictly mathematical order and the developmental needs of pupils, modified by the mathematical potential of the electronic calculator : some teaching strategies resulting from new influences in the syllabus
- Authors: Breetzke, Peter Roland
- Date: 1988
- Subjects: Mathematics -- Study and teaching (Secondary) -- South Africa , Calculators , Mathematics -- South Africa -- Outlines, syllabi, etc.
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1364 , http://hdl.handle.net/10962/d1001430
- Description: This study was motivated by the latest revision of the mathematics syllabuses of the Cape Education Department. The most important changes to content in the Senior Secondary Mathematics Syllabus (July 1984) are the introduction of calculus and linear programming, the substitution of a section on analytical geometry for vector algebra and the recall of the remainder and factor theorems. The way in which these changes were introduced left the task of integrating them into the teaching process in the hands of individual teachers. This is a task of extreme importance. If one's classroom practice is to simply plough one's way through the syllabus, one loses many opportunities to make the study of mathematics meaningful and worthwhile. Accepting the view of the spiral nature of the curriculum where one returns to concepts and procedures at increasing levels of sophistication, one needs to identify the position of topics in this spiral and to trace their conceptual foundations. Analytical geometry is in particular need of this treatment. Similarly there are many opportunities for preparing for the introduction of calculus. If the teaching of calculus is left until the last moments of the Standard 10 year without proper groundwork, the pupil will be left with little time to develop an understanding of the concepts involved. It is the advent of calculators which presents the greatest challenge to mathematics education. We ignore this challenge to the detriment of our teaching. Taken seriously calculators have the potential to exert a radical influence on the content of curricula and examinations. They bring into question the time we spend on teaching arithmetic algorithms and the priority given to algebraic manipulation. Numercial methods gain new prominence. Calculators can even breathe new life into the existing curriculum. Their computing power can be harnessed not only to carry out specific calculations but also to introduce new topics and for concept reinforcement. The purpose of this study has been to bring about a proper integration of the new sections into the existing syllabus and to give some instances of how the calculator can become an integral part of the teaching/learning process
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- Date Issued: 1988
The selection and evaluation of grey-level thresholds applied to digital images
- Authors: Brink, Anton David
- Date: 1988
- Subjects: Image processing -- Digital techniques
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5443 , http://hdl.handle.net/10962/d1001996
- Description: Many applications of image processing require the initial segmentation of the image by means of grey-level thresholding. In this thesis, the problems of automatic threshold selection and evaluation are addressed in order to find a universally applicable thresholding method. Three previously proposed threshold selection techniques are investigated, and two new methods are introduced. The results of applying these methods to several different images are evaluated using two threshold evaluation techniques, one subjective and one quantitative. It is found that no threshold selection technique is universally acceptable, as different methods work best with different images and applications
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- Date Issued: 1988
Environmental requirements for the hatchery rearing of African catfish Clarias Gariepinus (Pisces: Clariidae) larvae and juveniles
- Authors: Britz, P J (Peter Jacobus), 1959-
- Date: 1988
- Subjects: Catfishes -- Africa , Fish culture , Clariidae , Clarias
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5188 , http://hdl.handle.net/10962/d1001964 , Catfishes -- Africa , Fish culture , Clariidae , Clarias
- Description: Inadequate seed production has historically been a factor limiting the commercial culture of Clarias gariepinus. The need to determine the environmental requirements of larvae was identified, in order to facilitate their successful mass rearing in hatcheries. The effects of key environmental factors on the growth, survival and aspects of the behaviour of C. gariepinus larvae and juveniles were investigated under controlled conditions. A strong emphasis was placed on the interpretation of the observed responses in terms of the natural history of the animal. Larvae were obtained by artificially inducing and spawning feral adult broodfish. Larval growth rates were highest in the temperature range 26-33ºC, with a peak at 30ºC. Survival of larvae was high between 22 and 33ºC. The final temperature preferendum of juveniles, determined in a thermal gradient was 30ºC, and it was concluded that this temperature is probably optimal for most of the physiological processes of the animal. Larvae and juveniles displayed strong negative phototaxis. When reared under different photoperiod regimes, larval growth increased with longer dark periods, however a similar rate of mortality was recorded in all photoperiod treatments. The provision of cover was found to enhance larval growth under conditions of continual light (24L/OD), however under conditions of continual darkness (OL/24D) similar growth rates were recorded regardless of the presence or absence of cover. All growth rates in continual darkness (OL/24D) were higher than those in continual light (24L/OD), regardless of whether cover was provided or not. It was concluded that a OL/24D photoperiod is optimal for larval rearing. At salinities between 0 and 5% similar growth and mortality rates of larvae were recorded. At 7.5 % larval growth and survival rates were lower, and at 10 % all larvae died within 48 hours. The 96h-LCSO for unionised ammonia was found to be 2.3 mg/l. The cytological effects of unionised ammonia were evident as degenerative changes in the gill and liver tissues. In an investigation of tank hygiene, it was found that larval growth and survival rates were highest in tanks not cleaned at all. As the frequency of tank cleaning increased, the growth and survival rates of larvae decreased. When reared at densities ranging from 45-450/1, larval growth was found to be density dependent. A model of hatchery productivity (number larvae of standard size produced/time/vol.) was developed based on the density dependent nature of larval growth. The model predicts that maximum productivity, will be achieved at a rearing density of 1400/1. The high growth and survival rates obtained over a broad range of each environmental parameter investigated serve to explain how larvae survive and grow in their unstable floodplain habitat in nature. The broad environmental tolerances of C. gariepinus are of benefit with respect to the culture of larvae, as successful larval rearing is possible over a fairly wide range of environmental conditions.
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- Date Issued: 1988
Life history changes of two reef fish species in exploited and unexploited marine environments in South Africa
- Authors: Buxton, Colin David
- Date: 1988
- Subjects: Reef fishes -- Africa, Southern Chrysoblephus laticeps Chrysoblephus cristiceps
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5189 , http://hdl.handle.net/10962/d1001965
- Description: A detailed investigation into the life histories of Chrysoblephus laticeps and c. cristiceps in exploited and unexploited marine environments on the south-east coast of southern Africa is presented. The study provided information necessary for the evaluation of marine reserves as a management option for these and similar reef species. Visual underwater assessments showed a clear spatial separation between adults and juveniles of both species, suggesting a recruitment of juveniles into shallow water followed by a gradual outward migration into deeper water with age. Denslty estlmates of C. laticeps in the Noordhoek (0.0064 fish/m²) and Tsitslkamma (0.0254 fish/m²) areas were significantly different and were attributed to exploitation. Within area differences in density were also significantly correlated with temperature) depth and substratum relief. Similar comparisons for C. cristiceps were not possible because these fish shied away from divers. Habitat preferences were mirrored in the diets of both species which fed on a wide variety of reef associated benthic animals. Size of prey appeared to be gape limited, only larger fish being able to manipulate prey. Quantitative differences between the diets of fish sampled in different areas were a reflection of differences in available prey and not related to the relative density of predators. The dietary characteristics recorded in these fish were typical of search hunters. An age and growth study based on the examination of sectioned otoliths showed that both species were slow growing and long lived. Maximum recorded ages were 18 and 22 years for C. laticeps and C. cristiceps respectively. Growth rates in exploited and unexploited areas were not significantly different although there was an indication that growth was slower in the exploited areas for C. cristiceps. Several inconsistencies in otolith interpretation and terminology were evaluated. Contrary to other South African studies the results suggested that somatic growth was fastest just after spawning. This coincided with the winter months and was reflected by the deposition of a hyaline zone in the otolith. Two independent estimates, the Pauli derivation and visually assessed length frequency analysis, produced the same value for total mortality of C. laticeps in the Tsitsikamma area (0.2). This result, together with a significant difference in the rate of fishing mortality at different areas along the coast suggested that the populations sampled were discrete and supported the postulate that both species were sedentary. Further support was obtained from a mark-recapture study. Although sample numbers were low the results showed no evidence of large scale migratory patterns in these fish. An investigation of the reproductive biology of both fish showed that they were protogynous hermaphrodites, all males being derived from females with no evidence for polyandry. Males were shown to be capable of mating with a number of females and this, together with monandry, monochromatism and a small testis size, suggested a polygynous mating system in both species. Observations of the courtship behaviour in captive c. laticeps also supported polygyny. A significant difference in the mean size at sex reversal between unexploited and exploited populations supported the postulate that sex reversal was independent of the size or age of the animal. The size at which sex reversal occurred appeared to be dependent on sex ratio. A detailed yield per recruit analysis of the response of the population to different levels of fishing mortality and size at recruitment (t [subscript]r), showed that sex reversing species were particularly vulnerable to over fishing. This was due to a dramatic decline in the number of surviving individuals past t[subscript]r which resulted in a skewing of the sex ratio towards females. Evidence is presented to show that current legislation is inadequately protecting the spawner stock of both species. In conclusion it is shown that longevity, sex reversal, restricted movements and the occupation of a demersal habitat make these species particularly vulnerable to over exploitation in a size- selective fishery. The sustained yield in the linefishery is suggested to be a result of distant recruitment from relatively unexploited populations rather than the adequacy of current conservation measures. The need to protect the spawner stock is emphasised and the use of marine reserves as an additional protection for sedentary reef-dwelling species is therefore advocated.
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- Date Issued: 1988
Explanation in rule-based expert systems
- Authors: Carden, Kenneth John
- Date: 1988
- Subjects: Expert systems (Computer science) Ecology -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4569 , http://hdl.handle.net/10962/d1002034
- Description: The ability of an expert system to explain its reasoning is fundamental to the system's credibility. Explanations become even more vital in systems which use methods of uncertainty propagation. The research documented here describes the development of an explanation sub-system which interfaces with the P.R.O. Expert System Toolkit. This toolkit has been used in the development of three small ecological expert systems. This project has involved adapting the results of research in the field of explanation-generation, to the requirements of the ecologist users. The subsystem contains two major components. The first lists the rules that fired during a consultation. The second component comprises routines responsible for quantifying the effects on the system conclusions of the answers given to questions. These latter routines can be used to perform sensitivity analyses on the answers given. The incorporation of such routines in small expert systems is quite unique
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- Date Issued: 1988
The functions of narrative : a study of recent novelistic nonfiction
- Authors: Carlean, Kevin John
- Date: 1988
- Subjects: Reportage literature -- History and criticism , Nonfiction novel
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2176 , http://hdl.handle.net/10962/d1001827
- Description: Since Truman Capote's In Cold Blood: A True Account of a Multiple Murder and its Consequences was published in 1965, there have been many attempts to define and explain the phenomenon of the "non-fiction novel" as a unified narrative genre. Some of these attempts have been highly theoretical and scholarly, but most have been rather loose definitions referring to an extremely wide range of diverse factual narratives. Over the years, so many different works have been called "non-fiction novels" that it now seems as if the notion of such a unified genre is questionable. Surely it is not generically useful to say that such functionally distinct works as Oscar Lewis's La Vida: A Puerto Rican Family in the Culture of Poverty (1967) and Hunter S. Thompson's Fear and Loathing in Las Vegas: A Savage Journey to the Heart ot the American Dream (1971) belong in the same narrative category. The purpose of this study is to show that many of the works routinely referred to as "non-fiction novels" perform fundamentally different narrative functions and do not belong together in a unified genre. Roman Jakobson's model of communication and his notion of the "dominant function" are used to identify three functional categories into which the narratives discussed in the study logically fall: first, there are predominantly sociological works in which the referential function is the most important element of the communication; second, there are predominantly journalistic works in which the opinions of the writer or emotive function constitute the central narrative concern; and thirdly, we have works performing a dominant novelistic or aesthetic function in the sense that the secondary meanings and themes implied are the most important elements communicated. The thesis follows the following structure. In the introductory chapter, a critique of some of the major generic theories of the "non-fiction novel" as unified genre is offered. The purpose here is not to caricature what are sometimes extremely sophisticated studies. (Indeed, in my own analysis of texts, I am often indebted to the critical insights of the scholars whose theories I question in the introduction.) My purpose is merely to show that the corpus of works each writer refers to can be divided more logically between different dominant narrative functions. The introduction ends with a more detailed explanation of the adaptation of Jakobson's notion of "the dominant" and how it relates to the functional categories identified. Chapter 2 offers analyses of a group of documentary narratives that perform a dominant sociological function but have often been referred to as "non-fiction novels." The chapter starts with an analysis of James Agee's Let Us Now Praise Famous Men (1941), a text widely regarded as the first real American example of the "genre." This is followed by an examination of the anthropological works of Oscar Lewis: Five Families: Mexican Case Studles in the Culture of Poverty (1959), The Children of Sanchez: Autobiography of a Mexican Family (1964), Pedro Martinez: A Mexican Peasant and his Family (1964) and La Vida: A Puerto Rican Family in the Culture of Poverty. I conclude the chapter with an analysis of the recent sociological works of Studs Terkel: Division Street: America (1968), Hard Times: An oral History of the Great Depression (1970) and Working: People talk about what they do all day and how they feel about what they do (1974). In Chapter 3, the notion of subjective participation journalism is explained. This is followed by an analysis of three of the most famous and creative of the works that fall into this functional category: Hunter S. Thompson's Hell's Angels: The Strange and Terrible Saga of an Outlaw Motorcycle Gang (1966), Michael Herr's Vietnam classic, Dispatches (1977), and Norman Mailer's account of a famous protest march, The Armies of the Night: History as a Novel, The Novel as History (1968). Chapter 4 offers a discussion of three works that perform a dominant novelistic function in the realistic tradition of Dostoevski's Crime and Punishment. All three are based on actual murder cases, but the facts of the stories are subordinated to the novelistic themes the author wishes to abstract. They are: Meyer Levin's Compulsion (1957), Mailer's The Executioner's Song (1979) and Capote's In Cold Blood. From this outline, it may appear as if the study is loaded in favour of the sociological works discussed in Chapter 2. This is intentional because, although many critics have referred to them as "non-fiction novels", very little systematic and detailed analysis of these works as a corpus has been forthcoming. This long chapter is an attempt to redress the balance.
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- Date Issued: 1988
The role of male competition and female choice in the mating success of a Lek-breeding Southern African Cichlid fish Pseudocrenilabrus Philander (Pisces: Cichlidae)
- Authors: Chan, Tin-Yam
- Date: 1988
- Subjects: Cichlids -- Africa, Southern -- Physiology Courtship in animals Fishes -- Reproduction Cichlids Pseudocrenilabrus philander Lek-breeding Courtship Reproduction Spawning Competition Rivalry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5599 , http://hdl.handle.net/10962/d1002049
- Description: A lek-breeding cichlid fish Pseudocrenilabrus philander was studied experimentally. Females in choice-chamber experiments showed no active choice for male size and colour, or for other male attributes, but preferred males which courted most actively. In a laboratory lek, the significant determinants of the strongly skewed mating success in males were territory size, side-shake and female chasing frequency. Together these three variables explained 79% of the variation in male mating success, with territory size alone accounting for 75% of the variation and the other two variables each accounting for 2% of the remaining variation. As there was no difference in territory quality in the laboratory lek, territory size became the principal measure of the effect of male-male competition since it was directly related to dominance. Both side-shake and female chasing could be identified as the basic factors influencing female choice, as they had an immediate effect on the display-response mating system of females. Thus, the relative importance of these three variables indicated that sexual selection in this particular lek mating species operated chiefly through the agency of intrasexual competition for dominance. However, both female behaviour and their requirement for a prolonged pre-spawning courtship had the effect of promoting male rivalry and favouring mating with dominant males. Although the intense male competition excluded subordinate males from practising normal courtship behaviour, competitively inferior males might "make the best of a bad situation" by facultatively adopting an alternative sneaking tactic to gain access to females. Spawning intrusions by females to steal freshly-laid eggs also occurred frequently. However, territorial males appeared to be relatively more tolerant of female intruders than male sneakers. Interference during spawning could lead to a longer pre-spawning courtship and even multiple-mating by females. The results of the present study and the behavioural evidence shown by males and females did not support the ʺrunaway selection modelʺ of the mating pattern in terms of sexual selection in leks, but conformed to the rival ʺwar propaganda modelʺ
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- Date Issued: 1988
The presented case study aims to demonstrate the efficacy of psychotherapy with a child previously treated with medication
- Authors: Cheesman, C
- Date: 1988
- Subjects: Child psychotherapy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3167 , http://hdl.handle.net/10962/d1007730 , Child psychotherapy
- Description: The impetus for using the therapy with J.B. for this study was primarily the challenge inherent in the situation from the moment the parents and J.B. arrived for their family interview and assessment. They had been through many professionals by then, and much medication. They were sceptical of our intervention, since nothing to date had relieved the situation, and J.B. still had outbursts of rage towards his mother, he was still expressing suicidal ideation and anxiety. The challenge was particularly in relation to the mother, who had great difficulty conceptualising J.B. 's problems as being emotional and relational in nature - she was infinitely more comfortable with physiological interpretations of everything. This had the effect on the therapist and the supervisor of frequently reassuring their belief in psychotherapy as the treatment of choice in this case, or if in fact there was a lurking 'disease ' or organic cause to the child's behaviour. The pressure was thus considerable in this respect, despite the fact that the child had been examined physically and nothing found. This study aims to demonstrate the efficacy of psychotherapy, and the changes that took place, with this patient who was previously treated with medication.
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- Date Issued: 1988
Aspects of the biology of the musselcracker, Sparodon Durbanensis, and the bronze bream, Pachymetopon grande, (Pisces : Sparidae), with notes on the Eastern Cape recreational rock-angling and spear fisheries
- Authors: Clarke, John Ross
- Date: 1988
- Subjects: Sparidea -- South Africa Sparodon Durbanensis Bream fishing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5190 , http://hdl.handle.net/10962/d1001966
- Description: The musselcracker, Soarodon durbanensis, and the bronze bream, Pachymetopon arande, are important components of rock-angling and spearfishing catches In the Eastern Cape. Aspects of their biology, including age and growth, reproduction, nursery areas and feeding, were Investigated to provide a basis for the rational exploitation of the resource. Both species are slow-growing and long-lived. Growth in S. durbanensls was described by the von Bertalanffy growth equation: Lt(mm) = 1021.2(1-e⁻°.°⁹°°⁽t ⁻° .⁷°⁹⁾). The von Bertalanffy growth model did not describe the total data set in P. grande, but by excluding the zero and one year old fish the data were described by: Lt(mm) = 461.1(1-e⁻°.¹⁵³⁽t ⁺¹.⁶⁴°⁾). Detailed histological examination of gonadal development showed that S. durbanensis and P. grande are rudimentary hermaphrodites. Both species had restricted breeding seasons which coincided with peak exploitation. Results indicated that both species are group spawners with pelagic eggs. Size at 50% maturity in S. durbanensis and P. grande was determined at 350 and 300mm fork length, respectively, corresponding to ages of 4.5 and 5.5 years. Intertidal pools functioned as nursery areas for S. durbanensis during the first year, whereas subtidal waters were more important for larger juveniles. P. grande juveniles were commonly observed on subtidal weed beds to a depth of 10m. A size-related change in the diet of S. durbanensis was observed. The juveniles were omnivorous, feeding predominantly on gastropods, echinoids and chlorophytes. The adults fed on a variety of large, reef-associated invertebrates. P. grande were omnivorous, with macroalgae being the principal dietary component. This species appears to utilise the storage and extracellular carbohydrates of the macroalgae. Results showed that macroalgal degradation by gut endosymbionts and the utilisation of macroalgal epibionts does not appear to occur in this species. A detailed analysis of catch composition and catch per unit of effort In the Port Elizabeth rock-angling fishery and the Eastern Cape spearfishery emphasised the recreational importance of S. durbanensis and P. grande. The localised distribution, slow growth and late maturation in both species results in their being susceptible to over-exploitation in these size-selective fisheries. Current legislation protecting these fish is discussed in relation to the findings of this study and additional management measures are proposed.
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- Date Issued: 1988
Extractives from six species of Lamiaceae
- Authors: Davies-Coleman, Michael Trevor
- Date: 1988
- Subjects: Lamiaceae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4532 , http://hdl.handle.net/10962/d1016235
- Description: In continuation of the phytochemical studies of plants belonging to the Lamiaceae (formerly Labiatae) the acetone extractives of six Southern African species from this family have been examined. The genus Syncolostemon has not been investigated before and a new 6- substituted-5 ,6-dihydro-a-pyrone , synrotolide was isolated from S. rotundifolius. The structure of synrotolide was fully elucidated as 6fixii [3'R, 61S-(diacetyloxy)-4 1R, 5 1 8-(dihydroxy)-1~-hepteny~ -5,6-dihydro-2H-pyran- 2-one. Oleanolic acid is the major component of both~ rotundifolius and S. densifloris. The flavonol quercetin was isolated from S. densifloris as its 3, 3', 4' , 7 tetramethyl ether. A further 6-substituted-5,6-dihydro-a-pyrone, boronolide, was obtained from Tetradenia barberae. The structure of boronolide was known but the absolute stereochemistry was unassigned. Chemical degradation established the total structure of this compound as 6R- [1 'R, 2'R, 3's -(trisacetyloxy)heptyl] -5,6-dihydro-2H-pyran-2-one. The chemistry of naturally occuring 6-substituted-5,6-dihydro-apyrones has not as such been previously reviewed and a comprehensive review covering the literature up to June 1987 is presented here. Three known labdane diterpenoids nepetaefuran, hispanalone and dubiin were iso lated from Leonotis nepetaefolia, Ballota africana and L. ocymifolia var. ocymifolia (formerly~ dubia). Both~ nepetaefolia and L. dubia have been examined before. An X-ray analysis of saponified dubiin and a circular dichroism study of 6-deacetyldehydrodubiin and related compounds corroborated the structure of dubiin as 48, 5R, 6R, 8R, 9R, 10R-[6-acetoxy-15,16-epoxy-9-hydroxylabda-13 (16), 14-dien-19, 20- olactoneJ. The chemotaxonomic relationships of the genera Ballota and Leonotis are discussed.
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- Date Issued: 1988
Oor die kortkuns van John Miles
- Authors: De Beer, Marésa
- Date: 1988
- Subjects: Miles, John, 1938- -- Criticism and interpretation
- Language: Afrikaans
- Type: text , Thesis , Masters , MA
- Identifier: vital:3569 , http://hdl.handle.net/10962/d1002092
- Description: This thesis involves intensive analyses of some of the short-short stories in John Miles's Liefs nie op straat nie, in order to reveal the narrative strategies employed in each. In other words, it is geared to "the rules that govern ... textual actualization and, consequently, those rules that govern the way literary discourse functions as communication" (Riffaterre 1983: 158). Subsequently, attention is given to the interrelationship among the texts, the way in which they act upon one another and interact with the title of the volume, in order to establish the function of such relations. The following texts are analysed in consecutive chapters: "Lucy", "Lappies, kan jy my hoor, Lappies?", "Voorgevoel", "Dom Nakkie, my Dom Nakkie" and "Wie het nog Dom Nakkie gesien?", "Hy staan by die deur en hy klop", "Gustav gaan speel", and "Liefs nie op straat nie". In a concluding chapter the implications of the title are discussed with reference to all the texts in the volume, including those not analysed individually. It is concluded that, on the one hand, the expectations raised by the title are ironicized because the title is never "completed" explicitly, and because that which, by implication, should not be seen in public ("op straat"), is specifically situated in the street and scrutinized in close-up. But on the other hand the title also evokes a peculiar mentality present in all the texts, either in the narrators, or in the characters, or in both. The discussion of "Lucy" is focussed mainly on the contrast and interaction between the world of the child and that of the adult and on the way in which this interaction is actualized within the text through the contrast in the experience of time, the use of "mémoire involontaire", "durée" and the contrasts between (and overlapping of) narrative perspective and focalization. In respect of "Lappies, kan jy my hoor, Lappies?" special attention is paid to similarities and contrasts between this text and the traditional suspense story, notably the way in which conventional techniques are employed to create suspense, as well as to generate an entire subtext which eventually "relocates" the text on the niveau of the murderer's psychological dilemma. In discussing "Voorgevoel" emphasis is not placed primarily on what is conveyed by the narrator, but on the way in which his intentions are subverted both by the window pane through which he is looking and by the narration as such. In this way he is foregrounded and revealed as narrator, just as the text is foregrounded and revealed as literature, with the emphasis, in both cases, not only on their defence mechanisms but also on their impotence. "Dom Nakkie, my Dom Nakkie" and "Wie het nog Dom Nakkie gesien?" are grouped together in one chapter in order to illuminate the interaction between the two narratives in the first text, as well as the interaction between the two texts. Ultimately, they may be seen as three narratives juxtaposed through irony and relativism. The "triumph" of the "preferably not in public" mentality, both in the text and in society, is also illustrated by the interaction between the three narratives. In chapter, 5, in which "Hy staan by die deur en hy klop" is discussed, attention is focussed on the ironic function of the Biblical references, the contrast between Jan and the rest of society, and the way in which the "climax" is located within the Iserian "blank" in the text, so that the entire process of decoding is based on a filling in of that "blank" and its implications. "Gustav gaan speel" is based loosely on Barthes's lexia model, in order to determine the signifying process in the text, and also to demonstrate the way in which the text presupposes rereading. In the discussion of the title text it is revealed how the text is centered in the basic dichotomy between the narrator-as-writer and the journalist, and the way in which this polarity is relativized by the text as such. The text is demonstrated to be the credo of the volume as a whole as well as of the fiction of the Seventies in Afrikaans.
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- Date Issued: 1988
Effects of vitamin A on tumour and untransformed cells
- Authors: De Villiers, Diane Lynette
- Date: 1988
- Subjects: Vitamin A , Vitamin A in the body , Cancer -- Prevention
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3881 , http://hdl.handle.net/10962/d1001615
- Description: Vitamin A and its chemical analogues (retinoids) are known to play a role in the maintenance and differentiation of epithelial tissue. Retinoids have been shown to inhibit carcinogenesis in a number of tissues in experimental animals and to inhibit the growth of various untransformed and cancer cell lines in vitro. This study investigated the effect of retinyl acetate supplemented at concentrations of 1 μM, 5 μM, 10 μM and 100 μM to in vitro cultured untransformed LLCMK cells, and transformed BL-6 melanoma and human hepatoma cell lines. A small but non-significant effect of vitamin A addition on the growth of the untransformed cells was observed, while substantial inhibition of proliferation of the two tumour cell lines was found. At the cytotoxic level of 100 μM supplemented vitamin A, all three cell lines showed marked inhibition of growth. This led to an electron microscopy study to examine the ultrastructural effect of the vitamin A addition. At the low non-toxic levels of vitamin A addition (1 - 10 μM), no ultrastructural changes were observed in the untransformed cells. However, at a level of 5 μM and 10 μM vitamin A addition in the tumour cells, an increase in the size of suspected lipid droplets was observed. At the cytotoxic level of 100 μM supplemented vitamin A, large lipid droplets were very apparent, as was much cellular degeneration. This effect was more marked in the tumour cells than in the untransformed cells. The lipid nature of the droplets was confirmed by using the lipid stain, Sudan IV. In order to investigate the effect of added vitamin A at the cell surface level, an ELISA system was used to quantify the level of the cell surface glycoprotein, fibronectin, in the culture media. Vitamin A plays an important role in the production of mature fibronectin by participating in the glycosylation of the molecule. This study showed no major effect of added vitamin A on the release of fibronectin into the culture media. This did not, however, exclude the possibility that the vitamin A was involved in the production and enhanced binding of fibronectin to the cell surface, and was possibly also exerting an effect on the availability of fibronectin receptors. Further studies would, however, be required to substantiate such effects of vitamin A supplementation. No single mechanism of action of vitamin A on tumour cell growth inhibition was identified, but the possibility that at least two mechanisms exist, was suggested
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- Date Issued: 1988