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The Eucharist and history

  • Authors: Paterson, Torquil John Macleod
  • Date: 1990
  • Subjects: Lord's Supper , History -- Religious aspects
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:1311 , http://hdl.handle.net/10962/d1018262
  • Description: The thesis delineates an existential view of history, in which the eternal is defined as the ground of authentic human life which underlies true historical action. The historical is the manifestation of the eternal in the unique moment, and redefines the ahistorical conditions of human life. The ahistorical is the social and ideological conditioning of all human knowledge, usually presented in terms of various kinds of myth and ritual . The ahistorical contains both good and bad elements, but always has the tendency to become oppressive and is therefore constantly in conflict with the historical. The life of Jesus is described as the perfect expression of the eternal in true historical action, by which he came into conflict with the ahistorical of his society, as expressed in his death. By his resurrection, his life breaks the limitations of time and becomes transformative enabling all subsequent historical action. The eucharist is described as engaging with each of these dimensions of our existence. By being itself a ritual action containing a myth, the eucharist has an ahistorical form and therefore easily engages with the ahistorical dimensions of society. However, without a constant dialogue with the historical, the eucharist, as an ahistorical medium, can become allied to the dominant forces of society and become a means of oppression. The eucharist has at its centre the remembrance of the historical action of Jesus. True historical action in the present will result from a proper hermeneutic of the gospels. The eucharistic anamnesis must be regarded as part of the wider search for a relevant contemporary christology. The eucharist remembers the Last Supper, which is a parable of the whole life of Jesus and a prelude to his death and is a sacrifice in that it has a sacrificial form, and leads to our historical action, which will usually take the form of a conflict with the ahistorical and have sacrificial dimensions. The eternal only becomes present in our historical action, but the eucharist, by uniting us with the transforming power of the death and resurrection of Jesus, is a powerful aid to such action. The eucharist also provides the opportunity for resonances between Jesus and the ground of our being, thus enabling deep shifts of attitude and consciousness. Three fundamental prerequisites for human life are isolated and related to the eucharist: belonging, nurturing and giving. In order for the eucharist to ennable historical action is must hold these dimensions in tension. In its actual form it does this through the balance between the Words of Institution and the Epiclesis, which, in turn, provide the christological ground of the eucharist and relate this to the present through a particular pneumatology. The real presence is described by the thesis in a way which connects the eucharistic presence with the historical Jesus and leads to our historical action. Finally, some consequences of the thesis for Eucharistic practice are suggested. The relationship between the ahistorical form of the eucharist and the anamnesis is important. In this way the eucharist objectifies the ahistorical, reflects on this in terms of the historical action of Jesus, and reforms the ahistorical by modelling a response. This should lead to a more authentic expression of the eternal in the contemporary world
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  • Date Issued: 1990

The evaluation of qualitative examination questions at matriculation level in physics

  • Authors: Dixon, Charles Harwood
  • Date: 1990
  • Subjects: Physics -- Study and teaching (Secondary) , Physics -- Examinations, questions, etc.
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1373 , http://hdl.handle.net/10962/d1001439
  • Description: The style and format of Physics examination papers has changed markedly over the past hundred years. Physics was regarded formerly as a sub-division of Mathematics; hence, apart from giving formal statements of scientific laws, and some account of experimental procedures, examination candidates were required to spend most of their time, and to earn most of their marks by solving numerical problems. Most Physics examination papers today retain the emphasis on problem-solving by calculation. It has been recognised, however, that the ability to obtain correct numerical answers by substition in a formula does not necessarily imply understanding of the physical principles which underly the problem. There has been a reaction against the awarding of marks for algebraic or arithmetical manipulation. Bloom and his disciples, by calling on examiners to define precise behavioural objectives, have encouraged the development of qualitative questions. These require no calculation nor numerical answer, but do aim to test the candidate's insight, by requiring him either to explain phenomena in scientific terms, or to predict the outcome of changing conditions. In this investigation samples of both quantitative and qualitative questions were extracted from Physics papers past and present. A closer study was made of qualitative questions used in the Natal Senior Certificate Physics papers (both Higher Grade and Standard Grade) in November 1987. The examiners were asked to state the objective of each question, as well as its categorization in terms of a simplified Bloom taxonomy. Candidates' answers to these questions were extracted from the scripts written at a representative sample of Natal schools. In the case of multiple-choice questions, an item analysis was performed, and discrimination indices were calculated . The responses of individual candidates to the longer questions were collected, classified and discussed. In each case the effectiveness of the question was studied, as to whether or not it was successful in detecting the presence of correct scientific concepts in the candidates' thinking. It was concluded that most of the qualitative questions used by the examiners were effective. Suggestions were made as to how their efficacy could be improved. Much further study and experimentation are needed to develop the effective use of this type of question
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  • Date Issued: 1990

The future of the past in South African schools : curriculum development, school leaving examinations and syllabus design and assessment in history : a comparative study

  • Authors: Gunn, Alan Howard
  • Date: 1990
  • Subjects: Education -- South Africa , Education -- South Africa -- History , Education -- South Africa -- Forecasting
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1375 , http://hdl.handle.net/10962/d1001441
  • Description: This is a two-part study dealing with the curriculum, school leaving examinations and History as a school subject in England and South Africa. Part One is a developmental study. Developments in the curriculum of both countries since the Second World War are traced. In England this period is characterised by a shift from a somewhat laissez faire approach of the authorities at Whitehall to the curriculum of individual schools to the prescription that seems inherent in the National Curriculum. The outstanding development in South Africa during this period has been the introduction of a system of differentiated education. In contrast to minor developments in the South African school leaving examination system, England has witnessed the consolidation of the two-tier GCE and CSE system into a single examination at 16+, the GCSE. In discussing developments in History as a school subject, one is struck by the growth of the "new history" in England (this is described in some detail) against the relative lack of development (at "official" syllabus level) in South Africa where the subject remains rooted in the "traditional", chronological, content-based approach. Part Two of this study compares the current situation in England and South Africa at both the macro (ie. curriculum and school leaving examination systems) and micro (ie. History as a subject in the curriculum) levels. At the macro level the curriculum and school leaving examination systems in both England and South Africa are contrasted and one notes an increasing trend towards centralization in both countries. At the micro level use is made of "official" syllabuses and examination papers to contrast the "new history" approach in England with the "traditional" approach in South Africa. In the conclusion two broad possibilities for curriculum reform in South Africa are considered: Broad reform across the curriculum on the one hand and reforms in History on the other
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  • Date Issued: 1990

The geology and alteration-mineralisation of the Gamigab Tin Prospect, Damaraland, Namibia

  • Authors: Walraven, Felix Caspar
  • Date: 1990
  • Subjects: Mineralogy -- Namibia -- Damaraland , Geology -- Namibia -- Damaraland , Tin mines and mining -- Namibia -- Damaraland
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4956 , http://hdl.handle.net/10962/d1005568 , Mineralogy -- Namibia -- Damaraland , Geology -- Namibia -- Damaraland , Tin mines and mining -- Namibia -- Damaraland
  • Description: The stratigraphy at the Gamigab Sn prospect consists of two mainly schistose units separated by a thick marble unit which have been assigned to the Orusewa, the Karibib and the Kuiseb Formations respectively. Four phases of folding affected the lithologies with the south-south-west trending F2 folds defining the main structures in the region. The area underwent low grades of metamorphism. Temperatures were in the range 420° to 500°C and pressures less than 2 kbars. The effects of contact metamorphism are seen in the south-east and south-west. Regional metamorphism outlasted the deformation and contact metamorphism started late during deformation. Two Karoo-age intrusions penetrated the metasediments north of the mineralisation. One is an altered porphyry plug and the other is a weathered dolerite plug, the latter containing xenoliths of undeformed Karoo sediments. Cassiterite is hosted within east-west trending quartz veins that cross-cut previously altered schistose country rocks. The alteration types include sericitisation, tourmalinisation, carbonatisation and ferruginisation. Preliminary Rb/Sr dating on muscovite from the alteration zone suggests an age of 509 ± 11 Ma. Breccias of probable hydrothermal origin are spatially associated with the mineralisation. These hydraulic breccias occur in antiformal structures within the marble and developed in response to a sudden pressure release due to a build up of fluids at the contact between the schistose Orusewa and carbonate Karibib Formations.
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  • Date Issued: 1990

The idea of gaiety in Yeats's lyric poetry

  • Authors: Brady, Bronwyn
  • Date: 1990
  • Subjects: Yeats, W. B. (William Butler), 1865-1939 -- Criticism and interpretation , Lyric poetry -- History and criticism
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2324 , http://hdl.handle.net/10962/d1015642
  • Description: In June 1917 W.B. Yeats wrote to his father : Much of your thought resembles mine . . but mine is part of a religious system more or less logically worked out, a system which will I hope interest you as a form of poetry. I find the setting it all in order has helped my verse, has given me a new framework and new patterns. (Wade 1954, 627) The new framework and new patterns that he claimed to have found in his system generated a new, and for Yeats, radically different sort of poetry. Before 1919 (The Wild Swans at Coole), the poetry had as its subject various traditional themes: the pity of love; the romance and heroism of Irish mythology; the threat of age, change and death. The poetry up to this point is, formally speaking, highly skillful, but locked into its own admissions of failure to touch or incorporate reality in any but a romantically defeatist way. However, the order which Yeats refers to in his letter, and the system he generated as a propaedeutic to this new order, once assimilated into the habit and texture of the poetry, generated new topics of its own which made those of the earlier work seem subjective, self- indulgent and intellectually uninformed. Yeats's poetry now changed drastically in focus and form, from subjective to objective poetry. Whereas the earlier poetry had opposed reality with romantic heroism or selfdestructive despondency, the poetry subsequent to his change of practice, incorporates a new vision of reality as the intrinsic architechtonics of poetry itself. Now the measure of human and aesthetic completion is no longer an inexplicable and inscrutable sadness, but an intelligent and informed detachment, an energy of mind that Yeats called "gaiety". My thesis explores this energy of mind and what it meant for Yeats and his poetry. My contention is that the idea of gaiety provides a way for Yeats to grant meaning to his life, a way for him to create himself. As the poetry is completed thanks to the new system, so is the poet. In order to see this, it is necessary to read the poems as a series of collections, or stories, that resonate back and forth with meaning and qualification and understanding. Yeats's system is his myth, and he writes his poetry in terms of and informed by that myth, shaping and re-shaping the experience of the created and fictional self until it has meaning in a way that the real self does not. The thesis explores this process of creation firstly in theoretical terms, using Lotman's ideas of Story and Myth, and looking at Yeats's intellectual and poetic inheritance. It goes on to examine some of the great poems in an attempt to define gaiety, and how Yeats achieves it in the poetry, and then to look at the early, pre-system poems to see how they differ. Finally, it takes the last of Yeats's lyric collections, Last Poems, and shows how gaiety works in the most mature poetry when the poems are read as narrative events within a story.
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  • Date Issued: 1990

The National minimum wage reader

  • Authors: COSATU
  • Date: 1990
  • Subjects: COSATU
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/173584 , vital:42386
  • Description: Low wages are a cause of poverty. They are unjust and they lead to economic inefficiency. Low pay is not the result of "market forces" or of individual productivity. It is the result of the vulnerability of certain sectors of the workforce and the cost structure of low-wage industries. A National Minimum Wage is a practical solution that has been adopted in many countries. It is one of the demands of the Freedom Charter. The National Minimum Wage can be developed by COSATU as a powerful campaign tool in the fight for a living wage . The National Campaigns Conference, held in May 1990, asked the Living Wage Working Croup "to establish what National Minimum Wage should be suggested to develop a program of action to achieve a National Minimum Wage". The conference agreed that the level of the National Minimum Wage will be decided at the second National Campaigns Conference in August 1990. This reader pulls together all the documents and resolutions that have guided the Living Wage Working Group in its work on the National Minimum Wage.
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  • Date Issued: 1990

The Nyanga song

The observation of extended sources with the Hartebeesthoek radio telescope

  • Authors: Mountfort, Peter Ian
  • Date: 1990
  • Subjects: Radio telescopes
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5479 , http://hdl.handle.net/10962/d1005265
  • Description: The Hartebeesthoek Radio Telescope is well suited to mapping large areas of sky at 2.3 GHz because of the stability and sensitivity of the noise-adding radiometer (Nicolson, 1970) and cryogenic amplifier used at this frequency, the relatively large 20' beam of the 26 m dish antenna, and its high-speed drive capability. Telescope control programs were written for the Observatory's online computer for automated mapping. Effort centred on removing the curved baseline or 'background' from each Declination (Dec) scan, due to atmospheric and ground radiation contributions varying as the antenna is scanned. Initially these backgrounds were measured over a wide range of Hour Angle (HA) for the Dec range of a map, and an interpolated curve subtracted from each on-source scan for its HA. A common base level was established by comparison with drift scans (observed with the antenna stationary). These different observations (on- and off-source Dec scans and drift scans) were combined into one in the Skymap system by performing Dec scans at a fixed starting HA for a period long enough to permit 'cold sky' and the source to drift through. A background formed by fitting a smooth curve through the lowest sample at each Dec provides a consistent relative base level for all the scans in an observation. A high scanning speed is used so that observations may fruitfully be repeated three times and interleaved to build a reliable, fully sampled map. As each observation has its own background removed, it may be made at any HA. For comparison, maps of Upper Scorpio produced by the earlier method (Baart et al., 1980) and the Magellanic Cloud region produced by Skymap (Mountfort et al., 1987) are shown. Skymap provides a simple and flexible mapping method which relies on the stability of the noise-adding radiometer and high-speed repeated scans to produce good maps of large or small extent with little computation. Correction for drift is more difficult than with systems which use intersecting scans, such as the 'nodding' scans used by Haslam et al. (1981) or the Azimuth scans of Reich (1982).
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  • Date Issued: 1990

The petrogenesis of the Kirwan Basalts of Dronning Maud Land, Antarctica

  • Authors: Harris, Chris , Marsh, Julian S , Duncan, Andrew R , Erlank, Anthony J
  • Date: 1990
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/145472 , vital:38441 , https://doi.org/10.1093/petrology/31.2.341
  • Description: The 420 m thick sequence of Kirwan basalt crops out along the southernmost 50 km of the Kirwanveggen Escarpment (74°S, 6°W). There is little variation in major element chemistry of these basalts (SiO2 49·3–51·6 wt.%; MgO 5·1–6·6 wt.%), but the concentrations of certain incompatible elements (e.g., Zr) vary by factors of approximately two or more.
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  • Date Issued: 1990

The petrogenesis of the Kirwan Basalts of Dronning Maud Land, Antarctica

  • Authors: Harris, Chris , Marsh, Julian S , Duncan, Andrew R , Erlank, Anthony J
  • Date: 1990
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/145492 , vital:38443 , https://doi.org/10.1093/petrology/31.2.341
  • Description: The 420 m thick sequence of Kirwan basalt crops out along the southernmost 50 km of the Kirwanveggen Escarpment (74°S, 6°W). There is little variation in major element chemistry of these basalts (SiO2 49·3–51·6 wt.%; MgO 5·1–6·6 wt.%), but the concentrations of certain incompatible elements (e.g., Zr) vary by factors of approximately two or more.
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  • Date Issued: 1990

The pursuit of poetry : a defence

  • Authors: Gouws, John
  • Date: 1990
  • Subjects: Poetry
  • Language: English
  • Type: Text
  • Identifier: vital:632 , http://hdl.handle.net/10962/d1020701
  • Description: Inaugural lecture delivered at Rhodes University , Rhodes University Libraries (Digitisation)
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  • Date Issued: 1990

The rise of the French organ symphony with special reference to the works of Alexandre Guilmant and Charles-Marie Widor

  • Authors: Johnson, Bruce Richard
  • Date: 1990
  • Subjects: Guilmant, Alexandre, 1837-1911 Widor, Charles-Marie, 1844-1937 Organ music -- History and criticism
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:2643 , http://hdl.handle.net/10962/d1002308
  • Description: This thesis on the Rise of the French Organ Symphony refers especially to the relevant works of Alexandre Guilmant and Charles-Marie Widor. It commences with a survey of the historical background, dealing with the development of French organ music from the 16th to 19th Century and the development of organ building in France from the 17th to 19th Century. It then proceeds to descriptions of the organs of St Clotilde, La Trinité and St Sulpice Churches in Paris, which are followed by biographical profiles of Cesar Franck, Alexandre Guilmant and Charles-Marie Widor, respectively. The major part of the thesis is devoted to a detailed analysis of the organ sonatas of Guilmant and the organ symphonies of Widor, which are discussed from the point of their cyclic outline and aspects of form and of style. The final chapter summarises the major findings of the analytical research and evaluates by comparative method, the merits and achievements of the two composers. In addition, Appendices are attached, providing specifications of various French organs and pictorial material relevant to the thesis. A separate cassette tape features characteristic sounds of Cavailie-Coll organs.
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  • Date Issued: 1990

The role of the marriage counsellor in a Xhosa community: an exploratory-descriptive study

  • Authors: Phorie, Constancia Lineo
  • Date: 1990
  • Subjects: Marriage counselling -- South Africa Xhosa (African people) -- Marriage customs and rites Marriage customs Family
  • Language: English
  • Type: text , Thesis , Masters , MSocSc
  • Identifier: vital:686 , http://hdl.handle.net/10962/d1002011
  • Description: The focus of this study is on the role the marriage counsellor should play in the Black community. This role is being placed in sharp perspective as a result of social change affecting the Black family. Problem-solving, including marriage counselling has traditionally been done by the extended family. This role of the family as a natural support system has been weakened by factors such as urbanization and Westernisation. This has prompted Black couples experiencing in particular marriage problems to make use of professional marriage counselling services from specialised and other welfare agencies. A major problem in the rendering of professional counselling services is that they are to a great extent based on Western civilization as far as basic philosophy and underlying assumptions are concerned. Thus intervention modalities used for marital problems in the Black community do not address the real needs of the people. The main objective of this study was to investigate how marriage counselling services are perceived in the Black community. It is expected that research findings would assist the helping professions make the necessary adjustments to make marriage counselling approaches more relevant to problems experienced in married life in the Black community. The study revealed that the family in the Black community is still regarded as the main problem-solver although people do go beyond the family for assistance. The nuclear family has also started to emerge in the Black community and bonds to the bigger family systems are beginning to loosen. The research findings indicated clearly that there is a need for professional marriage counselling and that services of this nature should be extended further into the Black community. A problem in this regard however is that the community will have to be educated to use these services
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  • Date Issued: 1990

The silent patient: a consideration of Gendlin's recommendations in the treatment of a silent adolescent

  • Authors: Le Roux, J D
  • Date: 1990
  • Subjects: Uncatalogued
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10962/193054 , vital:45294
  • Description: This study comprises a dialogue between Gendlin's recommendations on the treatment of the silent patient and case-material taken from 39 sessions of psychodynamic psychotherapy with a 16 year old adolescent. The most characteristic feature of the therapy with this young person, was her pattern of silence and unresponsiveness. The aim of this study is to ascertain the usefulness of Gendlin's recommendations in the therapy of this category of patient. The dialogue between the suggested recommendations and the case- material served to illustrate the point that Gendlin's recommendations are of great value in the treatment of the silent adolescent. The value of these recommendations lie in their ability to comment meaningfully on the process of therapy with the silent patient by providing not only skills and techniques, but also a conceptual framework within which to contextualize the therapy. The recommendations were also found to be sensitive to some of the key issues of relevance to adolescence as a developmental phase. The case-study method was deemed an appropriate structure within which to conduct this examination. , Thesis (MA) -- Faculty of Humanities, Psychology, 1990
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  • Date Issued: 1990

The South African sugar industry

  • Authors: Lewis, Colin A
  • Date: 1990
  • Language: English
  • Type: Article
  • Identifier: vital:6695 , http://hdl.handle.net/10962/d1006730
  • Description: The sugar industry was established in Natal in the mid-nineteenth century. By the 1980s, South Africa produced c. 2 million metric tons of sugar per annum and, directly or indirectly, the industry supported almost one million people. Exports, which amounted for almost half the sugar produced in the 1970s, declined during the 1980s and low prices together with American and Canadian sanctions have forced the industry to consider alternative uses for sugar cane.
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  • Date Issued: 1990

The Southern African Development Coordination Conference (SADCC) : part of a whole or a cover?

  • Authors: Lubbe, Ingrid Lisa
  • Date: 1990
  • Subjects: Southern African Development Coordination Conference
  • Language: English
  • Type: text , Thesis , Masters , MA
  • Identifier: vital:2753 , http://hdl.handle.net/10962/d1002000
  • Description: The object of this analysis of the Southern African Development Coordination Conference (SADCC) was to examine the interaction between the states which comprise the organisation in terms of regional and international factors which either facilitated or constrained the pursuit of the organisation's economic goals. To this end a theoretical orientation which would place the organisation in context of regional and international political and economic interaction was necessary. International regime theory was used to place the organisation in an international context, and at the same time provided a theoretical dimension which could be used to analyse empirical evidence on the SADCC organisation's functioning. The application of regime theory clearly highlighted the fact that SADCC's economic goals are constrained by the degree to which all of the SADCC states are integrated on the economic level with western market economy and furthermore , by the fact that these links are reinforced for seven of the nine SADCC states by their economic dependence on South Africa. The above conclusion showed that in terms of the perpetuation of the SADCC organisation as an economic regime, according to the regime theory outlined in Chapter One, the goals of SADCC did not create a firm basis for economic cooperation in the long term. The future of the SADCC organisation in it's present form will depend on how long the racial policies of South Africa continue, for the analysis makes clear that the organisation has much more political than economic coherency. The use of a regime framework showed that in terms of the SADCC states individual economic positions, the historical and structural links between South Africa, the majority of the SADCC states and the West will continue indefinitely due to the strength of the structural economic links between the Southern African region and the western market economy. Thus the analysis proves, within the parameters of international regime theory, the lack of economic coherency within the SADCC organisation's goals, and the strength of the economic ties between the Southern African region and the West.
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  • Date Issued: 1990

The spiral curriculum, integrated teaching and structured learning of mathematics at the secondary level

  • Authors: Alummoottil, Joseph Michael
  • Date: 1990
  • Subjects: Mathematics -- Study and teaching (Secondary) -- South Africa Learning -- Mathematical models -- Research
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1769 , http://hdl.handle.net/10962/d1003654
  • Description: The investigator's experience of teaching mathematics at a college of education since 1983 has reinforced his conviction that trainee students come to college with significant gaps, weaknesses and faults in their (mathematical) conceptual structures, probably as a result of shortcomings in the mathematics teaching to which they have been exposed. The theme of this investigation is thus a natural choice that appeared to be of immediate relevance to secondary school mathematics teaching. The analysis of the issue leads to a unified perspective: the problem is placed in a theoretical framework where Bruner [spiral curriculum], Ausubel [structured learning] and Skemp [relational understanding] are brought together. How the curriculum, textbooks and examination influence school mathematics teaching is examined in some depth and the consequences investigated. Two specific topics, viz. the generalised Pythagorean relation and absolute value are investigated in relation to published work, curriculum and textbooks, and each (topic) is presented as a unifying theme in secondary mathematics to standard 9 pupils. The classroom exercise is assessed to test the hypothesis that structured, integrated presentation around a spiral curriculum promotes "relational understanding". Analysis of results supports the hypothesis.
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  • Date Issued: 1990

The stock identification of the Cape horse mackerel, Trachurus trachurus capensis (Pisces: Carangidae)

  • Authors: Naish, Kerry-Ann
  • Date: 1990
  • Subjects: Carangidae -- Identification , Trachurus trachurus -- Identification , Carangidae -- South Africa , Trachurus trachurus -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5320 , http://hdl.handle.net/10962/d1005165 , Carangidae -- Identification , Trachurus trachurus -- Identification , Carangidae -- South Africa , Trachurus trachurus -- South Africa
  • Description: Three stocks of the Cape horse mackerel, Trachurus trachurus capensis, have been recognised in the ICSEAF convention region off southern Africa (Figure 1) on the basis of catch distribution and biological analyses. They were identified as being off Namibia (ICSEAF Divisions 1 . 3 and 1.4), off the West Coast of South Africa (Div. 1.6) and off the South Coast (Div. 2.1 and 2.2). Recently, speculation as to the accuracy of the classification of the South African populations has arisen. The aim of this study was to determine the number of stocks In Divisions 1.6, 2.1 and 2.2, using methodology which assessed the spatial and temporal nature and the phenotypic and genotypic characteristics of the species. The distribution of horse mackerel was evaluated by studying the trends in catch data and length frequency distributions obtained from the demersal industry during 1986 to 1988 and from the demersal biomass cruises in 1987 and 1988. Adult fish, found in Div. 2.1 and 2.2, probably migrated; during the months in which horse mackerel were expected to spawn, CPUE values were higher over the central Agulhas Bank than in the east of the study region. During the quiescent period, catches and numbers were higher in the latter region. Juvenile horse mackerel were found in the nursery areas utilised by pelagic fish and it is likely that they were transported northward from the Agulhas Bank. A decrease in biomass of individuals in Div. 1.5 indicated a separation between a northern and a southern population. Analyses of the phenotype, or epigenetic characters, of horse mackerel were used as a further test of stock integrity. Monthly samples were drawn from Div. 1.6, 2.1 and 2.2 during May 1988 to June, 1989. Comparisons for the values obtained from growth, length-at-50%-maturity and the season of otolith ring formation from each region showed no significant variation in the phenotype. Morphometric analysis proved inconclusive. Monthly gonadosomatic indices show that fish south of the Orange River share the same spawning season. Reports from the literature show that horse mackerel in the latter region differ from those of northern Namibia in spawning season, age-at-50%-maturity and season of otolith ring formation. The genetic structure of the populations of horse mackerel was evaluated by means of a restriction enzyme analysis of the Mitochondrial DNA of 37 fish collected from Divisions 1.4, 1.5, 1.6, 2.1 and 2.2. Two composite genotypes of horse mackerel were found; one belonging to fish in Div. 1.4 and one to fish in Div. 1.6, 2.1 and 2.2. The genetic distance between the two genotypes, 0.07, was the expected distance between two populations at a subspecies level. Fish in Div. 1.5 consisted of both genotypes and may be a region of mixing between the two populations. The interpretation of results was cautioned; prevlous work has shown that the migration of a small number of individuals between two stocks can be expected to maintain a low variation between the populations. In concluding, it was recommended that the horse mackerel be managed as two stocks, one in Div. 1.3 and 1.4 and one in Div. 1.6, 2.1 and 2.2
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  • Date Issued: 1990

The taxonomy and life history of the blue stingray, Dasyatis marmorata capensis (Batoidea : Dasyatidae) from Southern Africa

  • Authors: Cowley, Paul D (Paul Denfer), 1964-
  • Date: 1990
  • Subjects: Stingrays -- Africa, Southern Dasyatidae
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5183 , http://hdl.handle.net/10962/d1001959
  • Description: The blue stingray, Dasyatis marmorata capensis is an important recreational shore angling species, especially amongst tournament anglers, in South Africa. The taxonomy and aspects of the biology of this species were investigated from specimens collected between March 1987 and May 1989, from various localities along the southern African coastline. Morphological comparisons were made between Dasyatis pastinaca, Dasyatis marmorata and the local variety. The results indicated that the local variety is different to D. pastinaca in colouration, disc length size, and vertebral and radial counts. The proposed new sub-species Dasyatis marmorata capensis is closest to Dasyatis marmorata of the north-eastern Atlantic coast, but differs in snout angle, disc length and snout to vent length. Analysis of catch per unit of effort data revealed that the blue stingray exhibits distinct seasonality. Adult and sub-adult fish undertake an annual onshore/offshore migration and invade the inshore region between spring and summer, while juveniles remain offshore and utilize this zone as a nursery area. Length-at-age and growth rates for both sexes were estimated from bands formed seasonally in the vertebral centra. The derived von Bertalanffy growth parameters indicated that females reach a greater asymptotic size (913.8 mm DW) and have a slower growth rate (K = -0.07) than males (531.8 mm DW, K = -0.17). Growth rates of juvenile captive specimens compared favourably with back calculated values, at approximately 65 mm/year, for the first year of growth. Dasyatis marmorata capensis is an aplacental viviparous elasmobranch with a well defined annual breeding cycle. Young are released , at a size of 170-200 mm DW, from October to December after a gestation period of approximately nine months. An average fecundity of 3.07 was calculated . Examination of gonadal development indicated that sexual maturity is first attained at a size of 408 and 500 mm DW in males and females, respectively, corresponding to ages 4.5 and 7 years. Size-related food habits were determined independently from three depth zones. The major prey items for each size class were directly related to the abundance of the infauna of the different depth zones. Polychaeta, amphipoda and stomatopoda were the major prey items in the offshore zone. In the nearshore zone, the dominant prey species were Balanoglossus capensis and Callianassa spp .. The high incidence of empty stomachs and the presence of prey items which occur in greatest abundance beyond the surf zone indicated that this zone is not utilized for the purposes of feeding.
  • Full Text:
  • Date Issued: 1990

The taxonomy, biogeography and biology of cow and frilled sharks (Chondrichthyes : Hexanchiformes)

  • Authors: Ebert, David A
  • Date: 1990
  • Subjects: Chondrichthyes Hexanchiformes Sharks
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5186 , http://hdl.handle.net/10962/d1001962
  • Description: This study was undertaken to investigate the taxonomy, biogeography and biology of cow and frilled sharks (Chondrichthyes: Hexanchiformes). This taxon comprises two families, four genera and six extant species. The hexanchoids are a distinctive group of sharks characterized by six or seven paired gill openings, a single dorsal fin and an anal fin. Adult males of this group lack a siphon sac, but have in its place a clasper sac. This structure, which develops along the claspers, is unique to the Hexanchiformes. Hexanchoid sharks are widely distributed in area and depth. This group ranges from coastal bays and harbors along the open coast out across the continental shelf and down along the slopes to considerable depths. They occur from the equatorial zone to sub-polar regions. However, little is known about the ecology and life history of these sharks. Intraspecific variation of meristic counts were generally low for the Hexanchidae, but high for the Chlamydoselachidae, indicating that subpopulations, subspecies or even additional, new species exist within this family. Based on the indicators used in this study, maturity in male frilled sharks was attained at 916 mm TL, perlon sharks between 700 and 800 mm TL, sixgill sharks approximately 3140 mm TL, bigeyed sixgill sharks at about 1250 mm TL and sevengill sharks at approximately 1550 mm TL. Male reproductive success did not appear to be seasonal since males were found to contain viable sperm all year round. Female perlon sharks begin maturing between 950 mm and 1100 mm TL. Gravid females and newborns were absent from the other size classes and it is suspected that they aggregate in different locations to those of adult males and non-breeding females. Adult females are known at 4210 mm TL and immature at 3500 mm TL, However, a more accurate estimate of the size at maturity is wanting. Newborn sixgills were caught off southern Namibia during mid to late summer over three successive seasons. The occurrence of gravid females carrying term embryos during spring months and newborns during the summer months suggests a late spring or summer pupping period. Sixgill and sevengill sharks give birth in areas of high primary productivity. Energetically, this is advantageous for the newborns to be placed in an area with an abundant food source. The rapid growth rates of sixgill and sevengill sharks over the first year would enhance their survivorship since neither species has many predators. The number of female sevengills entering the breeding population is regulated to ensure that some portion of the population is reproductively active at any one time. The "staggering" of females which enter into the breeding population in any given year indicates a two year reproductive cycle. Fecundity estimates for 19 specimens with a largest egg diameter of at least 40 mm indicates a litter size of 67 to 104. The recapture of an adult female sevengill in approximately the same location in which it was tagged suggests that the same individual sharks may return to the same breeding grounds. As with any predators, sharks tend to exploit advantages over their prey. The hexanchoids, especially the sevengill, have evolved complex foraging strategies including social facilitation whereby they actively hunt in packs for large prey species. Sharks of the order Hexanchiformes, although lacking the diversity of the major shark orders, nonetheless play an integral role in the marine environment. The group's success can be attributed to their apical trophic position. In most habitats in which they occur, hexanchoids have no comparable competitors since equivalent sized sympatric squaloids and carcharhinoids feed at a lower trophic level.
  • Full Text:
  • Date Issued: 1990
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