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Southern African Journal of Gerontology, volume 6, number 1, April 1997

  • Authors: Ferreira, Monica (editor) , Moller, Valerie , HSRC/UCT Centre for Gerontology
  • Date: 1997
  • Subjects: Gerontology -- South Africa , Older people -- Care -- South Africa
  • Language: English
  • Type: Text
  • Identifier: vital:8074 , http://hdl.handle.net/10962/d1012868
  • Description: [From Editorial] A variety of papers covering interesting and relevant topics and emanating from several countries are included in this number. Togonu-Bickersteth examines levels of satisfaction with care received from sons and daughters of older Yoruba in rural Nigeria. She finds that contrary to expectations, older women are more satisfied than older men with the assistance received from children. Makoni examines the effects of Alzheimer's disease as the disease progresses on the conversational ability of an older second-language speaker. Cattell reports on exploratory research among Zulu grandmothers and granddaughters in KwaZulu-Natal and finds that older women continue to have important roles in the socialization of granddaughters, especially regarding sexual behaviour. Van Dokkum makes out a case for a durable power of attorney, not yet provided for in South African legislation, which can help to protect older citizens against malpractices or exploitation when, because of impaired mental functioning, they are no longer able to look after their affairs. Lefroy gives an update on the Special Dementia Unit as an alternative residential care facility for afflicted older Australians and examines the advantages of this type of accommodation for individuals. their families and society. Finally, Moller reviews a book written by Nana Araba Apt of Ghana. entitled Coping with old age in a changing Africa. She concludes that readers will learn much from Apt's ideas on building on indigenous institutions to meet the challenges of ageing in Africa.
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  • Date Issued: 1997

Southern African Journal of Gerontology, volume 6, number 2, October 1997

  • Authors: Ferreira, Monica (editor) , Moller, Valerie , HSRC/UCT Centre for Gerontology
  • Date: 1997
  • Subjects: Gerontology -- South Africa , Older people -- Care -- South Africa
  • Language: English
  • Type: Text
  • Identifier: vital:8075 , http://hdl.handle.net/10962/d1012870
  • Description: [From Editorial] This Special Issue of the Journal comprises a selection of papers based on research on ageing in African countries, which were read at the Third Global Conference. The papers were revised and peer reviewed prior to acceptance by the Journal. The theme of the Special Issue is "Ageing in urban and rural Africa." Each of the papers included in the issue deals with a situation of ageing-in-place, a late-life migratory pattern, or the impact, or implications of social forces and social change on older Africans, in either an urban and/or a rural setting, or in both types of settings in Africa. The papers also draw together the main sub-themes and strands of the conference, particularly those relating to the family, ubuntu, urbanization, AIDS, and income security and poverty.
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  • Date Issued: 1997

Structural and stereochemical investigations of terrestrial and marine pyrone metabolites

  • Authors: Collett, Lynne Alison
  • Date: 1997
  • Subjects: Metabolites , Stereochemistry , Siphonaria
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4348 , http://hdl.handle.net/10962/d1005013 , Metabolites , Stereochemistry , Siphonaria
  • Description: This thesis presents an investigation into the chemistry of 6 substituted 5, 6-dihydro-a-pyrone compounds. A comprehensive review of these compounds was published in 1989 and the subsequent literature is covered in an updated review presented below. Eight 6-substituted 5,6-dihydro-a-pyrone metabolites from three different South African plant species Cryptocarya latijolia, Syncolostemon densiflorus, and Syncolostemon argenteus have been the subject of structural and stereochemical investigations. The absolute stereochemistry of the known compound "triacetate" from C. latijolia has been established as 6R-[2R,4S,6S-(triacetyloxy)heptylJ-5,6-dihydro-2H-pyran-2-one (74) using CD and acetonide formation with subsequent application of the modified Moshers method. The absolute stereochemistry of the related metabolite "diacetate", also from C. latijolia, has been assigned as 6R-[2S,4S-diacetyloxypentylJ-5,6-dihydro-2H-pyran-2-one (76). In addition, the outstanding stereochemistry at C-5' in syndenolide, from S. densiflorus, followed from conversion to its diacetonide and subsequent NMR analysis. Syndenolide is therefore 6R-[5S-(acetoxy)-IR,2R,3S-(trihydroxy)-heptylJ-5,6- dihydro-2H -pyran-2-one. The genus Syncolostemon has proved to be a rich source of a-pyrone compounds and the chemistry of S. argenteus, not investigated previously, was examined as part of an ongoing search for new 5,6-dihydro-a-pyrones. The study yielded five new a-pyrone natural products, synargentolide A-E. The structure of synargentolide A (82) has been assigned as 6R[4R,5R,6S-triacetyloxy-lE-heptenylJ-5,6-dihydro-2H-pyran-2-one using CD and NMR techniques. The structures of synargentolide B (87), C (92) and E (94) also followed from a detailed NMR analysis and the stereochemistry tentatively assigned based on CD and NMR data. Synargentolide D (93) was thermally unstable, and a paucity of material prevented stereochemical investigations, however the structure was determined from initial NMR analysis. The marine molluscs of the genus Siphonaria have only become the subject of chemical studies in the last fifteen years. These molluscs characteristically produce polypropionate type natural products. A review of Siphonarian polypropionate metabolites containing a pyrone functionality is presented. Examination of an endemic South African species Siphonaria serrata yielded one novel polypropionate metabolite containing a ),-pyrone functionality, siserrone A (131). The structure of this compound was unambiguously established using standard NMR experiments. The relative stereochemisty of the hemi-ketal moiety was assigned from a careful analysis of the ROESY NMR spectrum and the stereochemisty of the acyclic portion determined from a comparison of the 13C and 'H NMR data of a degradation product with the corresponding data of a synthetic compound. It was also established that the modified Moshers method could not be used to determine the absolute stereochemistry of the secondary hydroxy I substituent at C-11. The absolute stereochemistry of 131 was thus assigned in accordance with the proven stereochemistry of Siphonarian metabolites.
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  • Date Issued: 1997

Struggle in discourse the International's discourse against racism in the labour-movement in South Africa (1915-1919)

  • Authors: Caldwell, Marc Anthony
  • Date: 1997
  • Subjects: International (Johannesburg, South Africa) -- History , International Socialist League (S.A.) -- History , South African newspapers -- Language , Mass media and race relations -- South Africa , Mass media and language -- South Africa , Labor unions and mass media -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3419 , http://hdl.handle.net/10962/d1002872 , International (Johannesburg, South Africa) -- History , International Socialist League (S.A.) -- History , South African newspapers -- Language , Mass media and race relations -- South Africa , Mass media and language -- South Africa , Labor unions and mass media -- South Africa
  • Description: The International, as the weekly newspaper of the International Socialist League, articulated from 1915 to 1919 an ideology which stood opposed both to organised labour and nationalist movements in South Africa. This situation reflected significant historical struggles during this period, which constitutes essential background to the discourse of the International. The International's writers opposed the institution of trade unionism in the labour movement because it was fragmented on the lines of skill and race. They opposed both the National Party and the South African Native National Congress because they advocated racial (and national) rather than working class interests. Instead, these writers, according to their international socialist paradigm, advocated a working class united irrespective of race and skill at the level of industry. To analyse these ideological positions, discourse analysis provides a fruitful method for locating its dynamics in relation to other positions and extra-ideological (contextual) practices: The International's writers g~nerated a socialist position against racism by engaging in an ideological struggle in discourse. They articulated their anti-racist position from international socialism's critique of the 'languages' of both militarism and trade unionism in the discourse of labour. Within the discourse of militarism, the working class was signified as divided between hostile nations. These writers applied this as a metaphor to the division of the local labour movement and criticised the latter accordingly. In their view, just as workers were divided between the nations (nationalism), so they were divided within the nation (racism) in South Africa. One context cohered with the other, and both agreed with imperatives of international capitalism. This was fundamentally opposed to the principles of international socialism which characterised the International's discourse. Within the dominant discourse oflabour, workers were signified as divided between different trade unions on the basis of skills. Furthermore, in the South African context, trade unions organised only white workers, and ignored the far larger proportion of black labour. In this context, the International advocated industrial unionism, and criticised the narrow base of the white trade unions for fragmenting and weakening the working class in South African. The International's writers were thus led by the discourse of international socialism to a new discourse, whereby not white workers alone, but a racially-united working class movement would be the key to a socialist future in South Africa. Their struggle entailed a bid in and over discourse to rearticulate the sign of the 'native worker' within their own discourse as the dominant discourse type. Underpinning their struggle was a fundamental opposition to capitalist class relations.
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  • Date Issued: 1997

Student teachers' conceptualisations of 'significant' animals

  • Authors: Murtough, Neil
  • Date: 1997
  • Subjects: Environmental education -- South Africa Teachers -- Training of -- South Africa Human-animal relationships -- South Africa -- Folklore Zoology -- South Africa -- Folklore
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1775 , http://hdl.handle.net/10962/d1003660
  • Description: Constructivist approaches to teaching and learning are a well established component of the landscape of educational research, especially in Science education. This research took as its starting point the limited amount of social constructivist research available in the field of Environmental Education and responded to calls for further research. The research was designed within an interpretive tradition, as a critically phenomenological enquiry employing two methods; single case studies and a focus group. Data collection used progressively focused interview questions to proceed through a series of individual interview stages, starting with a simple description of conceptualisations and moving to deeper analysis of influences on, and use of conceptualisations. The focus group was designed as a forum to explore the pedagogic issues connected to the 'social negotiation of learning', based on data and insights gained from earlier interview stages. The goals of the study were to record data on the conceptualisations of animals perceived as significant by a group of Tsonga speaking students, and to seek insights into the formative influences on those conceptualisations. The research question, namely what contribution can social constructivist approaches to teaching and learning make to Environmental Education? guided an interpretation of the above data in terms of a range of social constructivist theories of learning. Theories of Radical and Social Constructivism as applied in Science education, although dominant orientations for educational research in constructivist learning, were challenged and found inappropriate as a basis to inform methodologies for Environmental Education. Instead Lave's (cited in O'Loughlin, 1992) socio-cultural approach to learning was explored as the basis to create a more useful perspective on an environmental education situation. Finally it was concluded that Lave's socio-cultural approach to learning may be a useful guide to helping a teacher- elicit the full range of conceptualisations present in an environmental education situation, but is not ultimately effective if no challenge and change comes about. Consequently, a socially critical constructivist teaching and learning approach was suggested In conclusion I commented on the interpretive research methodology employed and suggested an example of a socially critical methodology that could take this investigation further.
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  • Date Issued: 1997

Student-teachers' perspectives of the role of environmental education in geography education

  • Authors: Symmonds, Joanne
  • Date: 1997
  • Subjects: Geography -- Study and teaching -- Environmental aspects Environmental education
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1776 , http://hdl.handle.net/10962/d1003661
  • Description: The ideas contained in socially critical Environmental Education cannot be ignored given the current environmental crisis and the need to achieve democracy in South African society. In order to achieve this learners need to develop the skills to make informed decisions which will facilitate the achievement of a sustainable society. It is the contention of this research that a socially critical Environmental Education approach to education can facilitate the above. Teachers of formal secondary school Geography Education are in the position to implement socially critical Environmental Education into their teaching. This study therefore investigates the perspectives of student teachers regarding the role of Environmental Education in secondary school Geography Education. This was done within the Interpretative Paradigm using a case study which involved five Higher Diploma in Education Geography method students. The research has revealed that even though the Geography method students have been exposed to an Environmental Education course, in their teaching preparation and are motivated to use it, they have limited understanding of the theory underpinning Environmental Education and how to apply it to their Geography teaching. The problems of bridging theory and practice was apparent. Recommendations are made as how to best facilitate the gap between theory and practice.
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  • Date Issued: 1997

Studies of the biology and ecology of the high shore South African limpet, Helcion pectunculus (Mollusca : patellogastropoda)

  • Authors: Gray, David Richard
  • Date: 1997
  • Subjects: Mollusks -- South Africa Limpets -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5776 , http://hdl.handle.net/10962/d1005464
  • Description: Investigations were carried out into aspects of the bio!ogy and ecology of Helcion pectunculus along the coait of South Africa. These included studies of the distribution, density and biomass of the limpet at six sites along the east coast plus one site on the west coast; the growth of H pectunculus on both west and east coasts; a comparison of the reproductive biology of the east and west coast populations; the foraging activity and feeding behaviour of H pectunculus and the driving forces behind the rhythmic behaviour of this limpet; the importance of the crevice environment in the biology and ecology of H pectunculus. Helcion pectunculus has a restricted zonation, with the majority of animals residing in crevices in the upper Balanoid zone during diurnallowtides, although individuals were occasionally found in the lower Balanoid zone on shores with a gently sloping aspect. This limpet occurs in higher densities (50-lO0 individuals/m2) on shores which have large numbers of crevices and boulders i.e. quartzitic sandstone shores. On most shores, the ratio of males to females differed significantly from a 1: 1 ratio with the highest ratio being obtained on the west .. coast (3 males: 1 female). At all sites, the populations of H pectunculus exhibited strong sexual dimorphism. Males and females were always found to differ in size, with individuals of < 20 mm shell length generally being male whilst limpets with a shell length of> 22 mm were generally female. Helcion pectunculus grows allometrically, increasing in height faster than length, which is expected of a high shore gastropod mollusc attempting to reduce evaporative water loss. Growth rates were similar on both east and west coasts regardless of the differing oceanographic conditions. The theoretical values of Lmax were also similar being 30.86 mm and 30.71 mm respectively. Micro-growth bands are laid down within its' shell which have the same periodicity as the tidal cycle and these enabled age estimates to be made. Younger individuals were male whilst older animals were female, suggesting that H pectunculus is a protandrous hermaphrodite. Histological examination proved, unequivocally, that this limpet undergoes a protandric sex change, changing from male to female when they are about 2 years old. Both east and west coast popUlations had a marked reproductive cycle, exhibiting two spawning periods a year, one in April and another in November. The possibility that the reproductive pattern exhibited is now phylogeneticallyconstrained is discussed. It is suggested that H pectunculus has evolved a reproductive cycle which will allow its planktonic larvae to utilise the valuable phytoplankton bloom food source whilst using onshore winds to ensure that larvae are not transported out to sea and lost. The number of foraging excursions carried out by individuals of H pectunculus was found to have a significant effect on Gonad Index and hence potential reproductive output. The activity pattern of H pectunculus varied depending upon micro-habitat; animals inhabiting both east and west facing rock surfaces are active during nocturnal low tides whilst animals on west facing rock surfaces are also active during daytime low tides whilst in the shade. Limpets travel further during foraging excursions in winter (X = 85.53 cm) than in either spring (x = 55.7 cm) or summer (X = 48.8 cm) and also during spring low tides (x = 89.8 cm) compared with neaps (x = 40.9 cm). This limpet exhibits rigid homing to a fixed scar within a-crevice and feeding excursions were found to cons.is.t. of three distinct phases, a rapid outward phase, a slower foraging phase and a rapid homeward phase. Foraging was always highly directional, with a mean vector which took limpets onto an area of the rockface with the highest microalgal biomass and also the smoothest rock surface. Helcion pectunculus exhibits a free-running endogenous rhythm of locomotor activity with both circadian and circatidal components and it is suggested that this rhythm plays a role in allowing the limpet to avoid unfavourable environmental conditions. The exogenous entrainment factor of this endogenous rhythm was the time of exposure to air in the field. There was found to be an organized distribution of limpets within crevices with smaller, younger limpets being towards the back of the crevice and larger, older limpets towards the crevice mouth. It is hypothesized that juvenile limpets of this species actively select and settle at the backs of crevices responding to chemical cues of adult conspecifics. The crevice refuge supplies the limpets with a stable and buffered environment with higher relative humidities (X = 72.3%) and lower rock surface temperatures (X = 19.7°C) than adjacent exposed rock surfaces (X = 64.5%; x = 22.9°C). Limpet body temperatures were significantly lower in crevic~refuges compared to limpets on exposed rock surfaces. Body temperatures never exceeded the rock surface temperatures. It is suggested that this is the result of morphological adaptations such as shell ornamentation and allometric growth. Light levels above 1000 J.1E.m-2.s-1 inhibited foraging activity in H. pectunculuswhilst limpets subjected to 30-50% shade foraged even during daytime lowtides. This limpet is one of the least tenacious (2.75 ± 0.13 kg.cm-2 ) of all South African limpets and the possibility that wave activity governs both the activity patterns and homing behaviour of this limpet is discussed. Limpets deprived of a crevice refuge experienced extremely high mortalities, with 45% of the limpets being lost during the first high tide period. A hypothetical model of the hierarchy of exogenous factors controlling limpet foraging activity is introduced and discussed in relation to the results of this study. Finally, it is suggested that in addition to the "migratory" and "non-migratory" groups of limpets present on southern African shores a third group of limpets seem to be present which may be classed as "specialized non-migratory" species. These are species that do not migrate, garden or aggressively fight off like conspecifics. They have overcome the competition for space and food on intertidal rocky shores by adapting to a particular habitat which is exclusive to them alone. From the combined results of these studies, it can be stated that H. pectunculus has adapted physiologically, morphologically and behaviourally to successfully survive the extreme conditions in the upper Balanoid zone.
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  • Date Issued: 1997

Submission of the CWIU to the portfolio committee on Child and Family support

  • Authors: Chemical Workers Industrial Union (CWIU)
  • Date: 1997
  • Subjects: CWIU
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/170234 , vital:41871
  • Description: Having studied and extensively discussed the new child support and benefit system as agreed by cabinet on 5 March 1997, the CWIU Western Cape Women's Committee at its seminar held on 5-6 April 1997, noted j:tee following: 1) That the pSC-cess leading up to this development was not transparent and democratic despite its far-reaching consequences for the poorest sections of our people. 2) That the new system is designed to meet the requirements set by the government's economic strategy - Growth Employment and Redistibution (GEAR) for "fiscal restraint" and reducing the budget deficit and not meeting the needs of the majority of South Africans. This economic strategy of the government is in itself its response to the demands of local and international capital and not in line with the promise of "A better life for all" as embodied in the Reconstruction and Development Programme (RDP) and the new constitution which states the right for all "to have access to social security, including, if they are unable to support themselves and their dependents, appropriate social assistance". 3) That certain assumptions are made regarding the requirements of families, specifically women and their unsupported children, with regard to their survival, let alone decent living standards. In particular we refer to the new rates of R75 per child (under the age of 6 years) per month which is according to the government "slightly above the household subsistence level". This raises a number of serious questions and implications. Who determined these figures, what are they based on and who is it aimed at ? For years in the labour movement we have been confronted by capitalist bosses with similar "scientific statistics" across the bargaining table when fighting for decent wages. We have always rejected these as being based on existing poverty levels and seeking to perpetuate these conditions. These figures are also determined by academics hidden and protected by the privilege of the university environment, treating our poverty as mere scientific subjects for study to strengthen the ideological hand of their capitalist masters. We reject the figures and are convinced that the new rates will have the effect of increasing poverty. It has also been pointed out to us, for what it is worth, that the actual "Household Subsistence Level" figure is more than what the government has decided, ie. R96.83.
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  • Date Issued: 1997

Substituted catechols as complexing agents for the determination of bismuth, lead, copper and cadmium by adsorptive stripping voltammetry

  • Authors: Limson, Janice , Nyokong, Tebello
  • Date: 1997
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/293311 , vital:57074 , xlink:href="https://doi.org/10.1016/S0003-2670(96)00585-5"
  • Description: Copper, cadmium, lead and bismuth (> 5 μg ml−1) are determined by adsorptive cathodic stripping voltammetry (AdCSV) on a mercury film glassy carbon electrode, using catechol, 4-methylcatechol, 4-t-butylcatechol and resorcinol as complexing ligands. Complexes of lead, copper and bismuth with resorcinol showed the largest increase in current with increase in metal concentration, whereas complexes of these metals with 4-t-butylcatechol showed the lowest current response. Cadmium showed a different behaviour from the other three metals in that the highest current response was observed with 4-methylcatechol. The four metals could be determined simultaneously in the presence of resorcinol, although considerable interference was observed between bismuth and copper.
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  • Date Issued: 1997

Synthetic and physical organic studies of chromone derivatives

  • Authors: Ramaite, Ipfani David Isaiah
  • Date: 1997
  • Subjects: Benzopyrans Heterocyclic compounds -- Derivatives Coumarins
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4380 , http://hdl.handle.net/10962/d1005045
  • Description: A range of chromone-2-carboxylic acids has been prepared by condensing suitably substituted 2-hydroxyacetophenones with diethyl oxalate. pK₂ Studies of these acids revealed that 6- or 7-methoxy substituents decreased acidity while the 6-nitro group enhanced acidity; the strongest acid was the 3-chloro derivative, the increase in acidity being attributed to steric inhibition of acid-weakening delocalisation between the carboxyl group and the chromone system. Various chromone-2-carboxamides, derived from acid chloride precursors, were converted to polysubstituted acrylamides by nucleophilic ring-opening with selected amine nucleophiles. The main fragmentation patterns exhibited by these acrylamides were elucidated using a combination of low resolution, high resolution and meta-stable peak analysis, while the effect of substituents on the simultaneous internal rotation involving the carboxamide and enamine moieties were studied using dynamic NMR spectroscopy. Rotational barriers of ca. 67.1 kJmol ̄¹ and ca. 102 kJmol ̄¹ were found for the enamine and amide rotors, respectively. Several synthetic pathways were followed to prepare a series of 2-(N,N-dialkylamino)chromones which were subjected to detailed mass spectral analysis. In addition to substituent-specific fragmentations , the 2-aminochromones appear to fragment via 3 major pathways. The effect of substituents on the internal rotation of the amino moeity was investigated by variable temperature ¹H NMR spectroscopy and the resulting DNMR data was used to calculate the rotational barriers. Examination of the data reveals that the electron-releasing 6- and 7- substituents reduce the C-NMe₂ rotational barrier to ca. 43.5 kJmol ̄¹ , while the nitro analogue has the largest rotational barrier (ca. 46.1 kJmol ̄¹) because of the electron-withdrawing effect of this substituent.
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  • Date Issued: 1997

Teaching disciplinary discourse and implementing language-across-the-curriculum at tertiary level problems and prospects

  • Authors: Caldwell, Candice Anne
  • Date: 1997
  • Subjects: Rhodes University. Dept. of Psychology , Compensatory education -- South Africa , College students -- Study and teaching , College teachers -- Training of -- South Africa , Curriculum evaluation -- South Africa , Discourse analysis , Language arts -- Correlation with content subjects , Learning
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2340 , http://hdl.handle.net/10962/d1002622
  • Description: The premise of this thesis is that "learning", particularly in terms of students and universities, is capable of being seen as a specific and developed culture. This study is a contribution to the ethnography of that learning, the ultimate aim being to produce a descriptive theory of learning as a cultural system. This research was conducted within the context of the recent proposals made by the South African Commission on Higher Education. The proposals relevant to this study were, broadly, increased access to higher education and national funding for academic staff development programmes. There are, however, serious obstacles in the way of realising the aims of the higher education system outlined by the NCHE. Given the limited time and resources available for higher education development, it is imperative that the major flaws and obstacles in the system be identified and addressed as soon as possible. In view of this need, it was the concern of this study to conduct research which would assist in the designing of staff development programmes for academics teaching in English-medium tertiary institutions, like Rhodes University, where more than half the intake of first-year students already speaks English as a second, or other, language. Founded on the social constructionist view of knowledge, the aim of the study was to identify the needs of academic staff as well as the possible obstacles to the implementation of a "Language Across the Curriculum" policy. A genre-centred, ethnographic approach was used to access a disciplinary discourse community (the Psychology Department) in order to describe the practices of the community as well as to analyse the community's orders of discourse, particularly those which occurred at points of contact between lecturers and first-year students. It is argued that staff development programmes should promote the use of collaborative learning, which implies a reframing of the roles of both academic staff and students.
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  • Date Issued: 1997

Termination of psychotherapy : a phenomenological exploration of the therapist's and the patient's experience

The African National Congress' foreign policy in transition: change or continuity, 1989-1994

  • Authors: Machesa, Aubrey Mpho John Refiloe
  • Date: 1997
  • Subjects: African National Congress -- Foreign relations
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2797 , http://hdl.handle.net/10962/d1003007 , African National Congress -- Foreign relations
  • Description: But the central focus will be to explore the foreign policy transition by reflecting the theory that even though international and regional political developments had an impact on the foreign policy transition of the ANC, the internal and domestic political struggles that had evolved during the same time-frame as both the international and regional political developments also had major contributions to the foreign policy transition of the movement. Within this context, the study will also explore the preliminary contours of a post-apartheid foreign policy as perceived by the ANC as to how the country will be reintegrated into the political and economic world order.
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  • Date Issued: 1997

The application of a landscape diversity index using remote sensing and geographical information systems to identify degradation patterns in the Great Fish River Valley, Eastern Cape Province, South Africa

  • Authors: Tanser, Frank Courteney
  • Date: 1997
  • Subjects: Geographic information systems , Earth sciences -- Remote sensing , Environmental degradation -- South Africa -- Eastern Cape -- Great Fish River Valley , Forest degradation -- South Africa -- Eastern Cape -- Great Rish River Valley
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4814 , http://hdl.handle.net/10962/d1005488 , Geographic information systems , Earth sciences -- Remote sensing , Environmental degradation -- South Africa -- Eastern Cape -- Great Fish River Valley , Forest degradation -- South Africa -- Eastern Cape -- Great Rish River Valley
  • Description: Using a range of satellite-derived indices I describe. monitor and predict vegetation conditions that exist in the Great Fish River Valley, Eastern Cape. The heterogeneous nature of the area necessitates that the mapping of vegetation classes be accomplished using a combination of a supervised approach, an unsupervised approach and the use of a Moving Standard Deviation Index (MSDI). Nine vegetation classes are identified and mapped at an accuracy of 84%. The vegetation classes are strongly related to land-use and the communal areas demonstrate a reduction in palatable species and a shift towards dominance by a single species. Nature reserves and commercial rangeland are by contrast dominated by good condition vegetation types. The Modified Soil Adjusted Vegetation Index (MSA VI) is used to map the vegetation production in the study area. The influence of soil reflectance is reduced using this index. The MSA VI proves to be a good predictor of vegetation condition in the higher rainfall areas but not in the more semi-arid regions. The MSA VI has a significant relationship to rainfall but no absolute relationship to biomass. However, a stratification approach (on the basis of vegetation type) reveals that the MSA VI exhibits relationships to biomass in vegetation types occurring in the higher rainfall areas and consisting of a large cover of shrubs. A technique based on an index which describes landscape spatial variability is presented to assist in the interpretation of landscape condition. The research outlines a method for degradation assessment which overcomes many of the problems associated with cost and repeatability. Indices that attempt to provide a correlation with net primary productivity, e.g. NDVI, do not consider changes in the quality of net primary productivity. Landscape variability represents a measure of ecosystem change in the landscape that underlies the degradation process. The hypothesis is that healthy/undisturbed/stable landscapes tend to be less variable and homogenous than their degraded heterogenous counterparts. The Moving Standard Deviation Index (MSDI) is calculated by performing a 3 x 3 moving standard deviation window across Landsat Thematic Mapper (TM) band 3. The result is a sensitive indicator of landscape condition which is not affected by moisture availability and vegetation type. The MSDI shows a significant negative relationship to NDVI confirming its relationship to condition. The cross-classification of MSDI with NDVI allows the identification of invasive woody weeds which exhibit strong photosynthetic signals and would therefore be categorised as good condition using NDVI. Other ecosystems are investigated to determine the relationship between NDVI and MSDI. Where increase in NDVI is disturbance-induced (such as the Kalahari Desert) the relationship is positive. Where high NDVI values are indicative of good condition rangeland (such as the Fish River Valley) the relationship is negative. The MSDI therefore always exhibits a significant positive relationship to degradation irrespective of the relationship of NDVI to condition in the ecosystem.
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  • Date Issued: 1997

The biology of two important by-catch skate species on the Agulhas Bank, South Africa

  • Authors: Walmsley, Sarah Ann
  • Date: 1997
  • Subjects: Skates (Fishes) -- South Africa -- Physiology
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5240 , http://hdl.handle.net/10962/d1005083 , Skates (Fishes) -- South Africa -- Physiology
  • Description: Members of the family Rajidae are common components of the demersal trawl fishery, contributing around 1% to the total catch. However, apart from a single species all South African rajids are currently discarded. With demands for new protein sources ever-increasing, it is possible that currently underutilised species, such as the skates will be utilized to a greater extent. Raja wallacei and R.pullopunctata are common trawler by-catch species, ranging along most of the South African coast. The current study allred to further knowledge on the population biology of both species through age and growth, reproductive and feeding studies. The study also allred to assess whether any of the South African skate species show the potential for utilization as a food source. Band counts of vertebral centra were used to determine growth parameters and generate growth curves for males and females of both species. Growth was significantly different between the sexes. In both cases, females grew slower than males but reached a greater asymptotic disc width. As with other elasmobranchs, R.wallacei and R.pullopunctata are long-lived and slow growing. As with all other skates, the study species are oviparous laying large, yolked eggs in tough, leathery cases on the sea bed. The onset of maturity occurs at a large size (approximately 400mm disc width (10-11 years of age) for R.wallacei and 600mm disc width (12-13 years of age) for Rpullopunctata) and is very rapid. The oldest R.wallacei and R.pullopunctata observed were 16 and 18 years of age, respectively. No distinct breeding season was determined and no nursery areas were observed. A large proportion of individuals, especially R.pullopunctata was immature. Both species fed primarily on crustaceans and teleosts with an ontogenetic shift in diet from mysids, amphipods, isopods and bregmatocerids to larger Gnathophis sp., Mursia cristimanus and carid shrimps. Large discrepancies were seen in the diet of animals spatially, temporally and between research and commercially-caught animals. Disc-width frequency data was limited but suggested that both species show preference for depths of 100-300m. Size distribution did not appear to be affected by depth, although the data set was limited. A paucity of large individuals in the catch may indicate that stocks are suffering from growth overfishing by trawling operations. Historical and observer data showed that although skates are common components of the by-catch, the potential for greater use is limited. The biscuit skate, R.straeleni, on the west coast is the only species that could be better utilized. If skates are treated as a single group the potential is increased but this causes problems in assessing stocks.
  • Full Text:
  • Date Issued: 1997

The development potential of Kwazulu-Natal aquifers for rural water supply

  • Authors: King, Georgina
  • Date: 1997
  • Subjects: Aquifers -- South Africa -- KwaZulu-Natal , Water-supply, Rural -- South Africa -- KwaZulu-Natal , Hydrology -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4938 , http://hdl.handle.net/10962/d1005550 , Aquifers -- South Africa -- KwaZulu-Natal , Water-supply, Rural -- South Africa -- KwaZulu-Natal , Hydrology -- South Africa
  • Description: The supply of water to 'disadvantaged' areas of KwaZulu-Natal has in the past received low priority. Local government is now faced with supplying water to large, sometimes dispersed, rural populations. Groundwater has been utilised informally as a water supply for some years, but the impetus provided by the Department of Water Affairs and Forestry's White Paper has compelled those responsible for water supply to seriously consider groundwater as a sustainable option. The development potential or success of groundwater in its role as a reliable water supply is dependent on acceptance of the resource by the communities, appropriate level of service, yield sustainability and safe quality. Apart from the social aspects, the yield and groundwater quality characteristics of the aquifers under consideration must be used to determine the best hydrogeological features to target during exploration. A total of 993 borehole records, from a recent government drought relief programme, were used to compare the yield, water quality and best geophysical exploration and drilling techniques of the main hydrolithologies in rural KwaZulu-Natal. The results of comparative analysis shows that the competent rocks of the Natal Group and Natal Metamorphic Province and the karstic Uloa Formation of the Maputaland Group have the best overall potential for water supply. The unconsolidated sediments of the Maputaland Group also have good potential, but have some salinity problems. The Karoo Supergroup sediments and volcanics have moderate potential, with the argillaceous rocks having the worst potential of the Karoo rocks. The contacts between the Ecca Group shales and sandstone have the best potential of the Karoo Supergroup sedimentary hydrolithologies. Fractures clearly enhance the groundwater potential of most hydrolithologies, with fractured Dwyka Group tillites rated as having one of the best development potentials of all the hydrogeological targets in KwaZulu-Natal, despite the hydrolithology's poor water-bearing characteristics. Dolerite contacts with sedimentary rocks are commonly targeted features in groundwater development. However, the results from this research showed that, apart from the Natal Group's contact with dolerite, these targets have poor development potential. In general, contacts between different hydro lithologies. Health related quality was found to be adversely affected in argillaceous hydrolithologies, such as the majority of Karoo rocks which had high levels of sodium and chloride and Natal Metamorphic Province schists which had elevated sodium, chloride and fluoride. Crystalline and arenaceous hydrolithologies generally exhibited good quality groundwater. A comparison between the different geophysical methods for each target feature indicates that there are appropriate methods to use to detect anomalies related to water-bearing features. The large number of dry boreholes drilled in locations with recorded geophysical anomalies can be either a function of the water-bearing characteristics of the formation, human error or background noise. The cost of using the different geophysical methods vary considerably. The order of increasing cost is magnetics, VLF, EM-34, electrical resistivity profiling followed by vertical electrical sounding. Drilling has a large influence on the development potential of certain aquifers due to the high costs involved. Most of the secondary aquifers will require percussion drilling which is the cheapest method of drilling commonly used. Some very unstable formations within fractured or highly weathered rock may need ODEX drilling to enable drilling to advance. ODEX drilling in these conditions is very costly and can double the cost of drilling compared to air percussion. The unconsolidated sediments of the Maputaland Group can only be drilled by mud rotary or ODEX techniques. The relative costs of these two methods arer very similar with ODEX being slightly cheaper. Because of the high expense of drilling in the sands it is recommended that alternative sources, possibly from shallow hand-dug wells, be considered as appropriate methods of accessing groundwater. The aspects of groundwater yield and quality of aquifers, appropriate geophysical siting and drilling methods, together with social considerations will all contribute to the success of groundwater development in rural KwaZulu-Natal.
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  • Date Issued: 1997

The effect of elevated CO₂ on Phaseolus vulgaris L. cv Contender

  • Authors: Mjwara, Jabulani Michael
  • Date: 1997
  • Subjects: Plants -- Effect of carbon dioxide on Kidney bean
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4215 , http://hdl.handle.net/10962/d1003784
  • Description: The response of Phaseolus vulgaris L. cv. Contender grown in controlled environmental conditions, at either ambient or elevated (360 and 700 μmol mol ̄¹, respectively) CO₂ concentrations ([CO₂]), was monitored from 10 days after germination (DAG) until the onset of senescence. Elevated CO₂ had a pronounced effect on total plant height (TPH), leaf area (LA), dry weight (DW) accumulation and specific leaf area (SLA). All of these were significantly increased by elevated [CO₂] with the exception of SLA, which was significantly reduced. Except for higher initial relative growth rates (RGR) in CO₂-enriched plants, RGR did not differ significantly between the two CO₂ treatments throughout the remainder of growth period. While growth parameters clearly differed between CO₂ treatments, the effects of CO₂ on many physiological processes including net assimilation rate (NAR), Rubisco activity, and some foliar nutrient concentrations were largely transient. For example, CO₂ enrichment significantly increased NAR, but from 20 DAG onward, NAR declined to levels measured on plants grown under ambient CO₂. Similarly, the decline in both foliar N concentration and Rubisco activity in CO₂-enriched plants after 20 DAG was significantly greater than the decline observed for ambient CO₂ plants. Soluble leaf protein and total chlorophylls (a+b) were also significantly reduced in plants grown under elevated CO₂. Chlorophyll (a/b) ratios increased with time underelevated CO₂, indicating that the rate of decline of chlorophyll b was higher than that of chorophyll α. No significant changes in total carotenoid (x+c) levels were observed in either CO₂ treatment. Under enhanced CO₂, the foliar concentrations of K and Mn were increased significantly, while P, Ca, Fe and Zn were reduced significantly. However, changes in Mg and Cu concentrations were not significant. High CO₂-grown plants also exhibited pronounced leaf discoloration or chlorosis, coupled with a significant reduction in leaf longevity. The levels of non-structural carbohydrates (sucrose, glucose, fructose and starch) and nitrogenous compounds (nitrogen, total soluble proteins and free amino acids) were determined for leaves and developing seeds of P. vulgaris. Leaf tissue of elevated CO₂-grown plants accumulated significantly higher levels of both soluble sugars and starch. Leaf ultrastructure revealed considerable erilargement of starch grain sizes with surface areas more than five times larger compared to those of control plants. No apparent differences in structure and membrane integrity of chloroplasts in both CO₂ treatments were noted. Although ambient CO₂-grown plants had comparatively low levels of non-structural carbohydrates (NSC), they accumulated significantly higher levels of nitrogenous compounds. The levels of NSC were consistently higher in seeds of plants grown under elevated CO₂. In comparison to plants grown at elevated [CO₂], pods and seeds of ambient CO₂-grown plants had significantly larger pools of free amino compounds and N. Stomatal conductance (gs) declined significantly, as expected for plants grown under elevated CO₂. This was accompanied by a decline in transpiration rates (E). Reduced gs and E led to high AlE ratio, which meant improved water use efficiency (WUE) values for CO₂-enriched bean plants. Leaf carbon isotope discrimination (∆) against the heavier isotope of carbon (¹³C), has been used to select for high WUE in C₃ plants. In plants grown at elevated CO₂ concentration, ,1 was significantly reduced. Although ∆ was negatively correlated with WUE in both CO₂ treatments, the correlation was steeper and highly negative for CO₂-enriched plants. These results indicate underlying differences in gas-exchange physiology, including stomatal responses between ambient and elevated CO₂-grown plants. Photosynthetic acclimation was investigated using the response of assimilation to internal carbon dioxide concentration (A/C₁ curves). At early stages of growth, the initial slope of the A/C₁ response curve did not differ with CO₂ treatment. In contrast, CO₂-saturated photosynthetic rate (Amax) was significantly higher in plants grown under elevated versus ambient CO₂ at 15 DAG. However, at subsequent stages of growth both the initial slope and Amax declined in bean plants grown in elevated CO₂. Apparent carboxylation efficiency (ACE, estimated from the initial slope of A/C₁ response) values followed a similar trend and were significantly reduced in CO₂-enriched plants. These results indicate that acclimation or negative adjustment of photosynthesis may have been caused by a combination of both stomatal and biochemical limitations. Bean plants grown under conditions of elevated atmospheric CO₂ flowered 3 to 4 days earlier, and produced significantly more flowers and pods than plants grown at ambient conditions. Plants grown at elevated CO₂ aborted 22 and 20% more flowers and pods, respectively, than plants grown at ambient CO₂. Elevated CO₂ also significantly increased the number of tillers or lateral branches produced by plants, which contributed to a significant increase in pod number and seed yield in these plants. Although plants grown at elevated CO₂ produced on average 8 seeds per pod, while plants grown under ambient CO2 conditions produced 5 seeds per pod, the greater number of seeds was offset by lower seed weights in plants grown under _ elevated CO₂. Thus, despite high seed yield in beans grown under elevated CO₂, the harvest index (HI) did not change significantly between CO₂ treatments.
  • Full Text:
  • Date Issued: 1997

The effect of work-hardening on the physical work capacity of manual labourers within South African industry

  • Authors: Jacka, Karen-Louise
  • Date: 1997
  • Subjects: Human engineering , Industrial accidents -- South Africa , Industrial safety -- South Africa , Musculoskeletal system -- Wounds and injuries
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:5165 , http://hdl.handle.net/10962/d1016237
  • Description: South Africa is a labour-intensive industrially developing country. As a result, in excess of 200 000 workers suffer from musculoskeletal injuries in a year. Research is thus essential to develop more effective strategies in the reduction and rehabilitation of occupational musculoskeletal disorders within industry. It was the hypothesis of this study that by improving the physical work capacity of manual labourers, through participation in an occupation specific work-hardening programme, that the ergonomic stress index and therefore the occurrence of musculoskeletal injuries within industry, may be reduced. Twenty-five male Black and Coloured manual labourers volunteered to participate in this study. In addition to in situ task analyses, the subjects participated in cardiovascular and strength assessments in the laboratory, both pre- and post-participation in the ten-week work-hardening programme. The data were statistically analyzed in order to identify any significant • improvements in the workers' physical work capacity, as measured by cardiovascular, strength and perceptual responses, following the period of work-hardening. Two significant reductions were noted in measures of working heart rate together with significant improvements in grip strength and trunk strength tested at a velocity of 60°.sec·1 at the post-conditioning assessments. In conclusion, the ten-week work-hardening programme resulted in nominal improvements in all the cardiovascular measures and significant improvements in the subjects' strength performance. However, industrialists must recognise that this study dealt with only one aspect of reducing the ergonomic stress index at the workplace and realise that, in addition to this focus, it remains essential to design the task to fit the human operator.
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  • Date Issued: 1997

The honeybees, Apis mellifera Linnaeus (Hymenoptera: Apidae) of woodland savanna of southeastern Africa

  • Authors: Radloff, Sarah E , Hepburn, H Randall , Villet, Martin H
  • Date: 1997
  • Language: English
  • Type: Article
  • Identifier: vital:6829 , http://hdl.handle.net/10962/d1012341
  • Description: The morphometric characters and sting pheromones of worker honeybees, Apis mellifera Linnaeus, were analysed by multivariate methods to identify discrete populations in the southeastern woodland savanna of Africa. A discrete population in Mozambique is classified as A. m. litorea Smith, a second in Zimbabwe as A. m. scutellata Lepeletier and a third group in southwestern Zambia as A.m. adansonii Latreille. A zone of introgression between the last two subspecies occurs in south-central Zambia and in the Zambezi Valley.
  • Full Text:
  • Date Issued: 1997

The human skin blanching assay for in vivo topical corticosteroid assessment. II. Subject- and observer-dependent variation in blanching responses

  • Authors: Haigh, John M , Meyer, Eric , Smith, Eric W , Kanfer, Isadore
  • Date: 1997
  • Language: English
  • Type: text , Article
  • Identifier: vital:6382 , http://hdl.handle.net/10962/d1006300
  • Description: The human skin blanching (vasoconstriction) assay for the assessment of topical corticosteroids has been in use for over 30 years, the intensity of the drug-induced blanching being assessed subjectively by eye. Both arms of several male and female volunteers are used for product application and more than one observer is used to estimate the degree of induced blanching. There are, therefore, numerous variables which are inherent in the assay procedure. This investigation consisted of three identical trials performed at 8-week intervals, utilising the same 18 volunteers and the same three observers in an attempt to address the question of reproducibility of the assay. From the results obtained it is clear that the assay methodology is capable of consistently distinguishing, on a rank order basis, between preparations which show similar blanching (chemically-equivalent formulations). The similarity of the results for the three individual trials gives considerable confidence to results produced using this methodology. An experiment designed to test the reproducibility of the blanching scores showed that the observers are capable of producing identical results even though visual observation is highly subjective.
  • Full Text:
  • Date Issued: 1997
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