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Preliminary investigation of the molecular pathogenicity determinants of Xanthomonas campestris pv. zeae

  • Authors: Downing, T G
  • Date: 1998
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4066 , http://hdl.handle.net/10962/d1004922
  • Description: Xanthomonas campestris pv. zeae was shown to posses a vast range of potential plant cell wall degrading enzymes including at least one protease, a carboxymethylcellulase, pectin lyase, polygalacturonase and a B-endoglucanase. Replicon stability and transfer system efficiencies were determined for a range of oriC, and oriT -tra combinations, and suitable vectors were constructed and identified for insertional inactivation by homologous recombination. Ideal suicide replicons were found to be pACYC184 and p15A, while P, Wand Q group replicons were supported by X campestris pv. zeae. Group P and group N transfer systems were shown to be highly efficient in intra-genus matings between Escherichia coli and X campestris pv. zeae, with the exception of P-tra systems in trans for the delivery of Tn5. Various cloning vectors were tested for stability and mobility. Tn5 was shown to transpose at high frequencies into the genome of the bacterial plant pathogen, and insertion was relatively random. Suitable screening assays were established to allow rapid isolation of mutants with potential virulence or pathogenic deviations, after mutagenesis. Two non-pathogenic mutants were identified, one of which was a putative hrp·, while the other was a leaky virulence. A single mutant showing 40% reduced protease activity was also shown to exhibit reduced virulence indicating a minor role for the protease in pathogenicity. The majority of virulence mutants showed altered growth in different levels of nutritional availability and complexity. Nutritional viability (the ability to acquire and use nutrients at a sufficient rate to grow fast enough to overcome host defences) was shown to be essential for virulence and possibly pathogenicity. Wild-type in-planta behaviour was analysed and growth and spread patterns typical for pathogenic response identified. Chief amongst these was the requirement for a threshold level of cells per leaf area or length, before symptoms could develop. Occlusion of vascular bundles was shown not to be the primary factor in the pathogenicity of X campestris pv. zeae. Threshold levels for lesion development indicate the absence of a diffusable lesion forming element, and possibly the requirement of cell density for induction of certain functions. , KMBT_363
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Prince Edward Islands' offshore oceanographic study: report of research cruise April-May 1997

  • Authors: Pakhomov, Evgeny A , Froneman, P William , Ansorge, Isabelle J
  • Date: 1998
  • Language: English
  • Type: text , article
  • Identifier: vital:6939 , http://hdl.handle.net/10520/AJA00382353_9017 , https://journals.co.za/content/sajsci/94/4/AJA00382353_9017 , http://hdl.handle.net/10962/d1011962
  • Description: preprint , Focuses on the preliminary results of the second cruise of the Marion Island Oceanographic Study designed to provide oceanological observations off Prince Edward Islands from April 25 to May 28, 1997. Physical and chemical oceanographic results; Surface seawater temperature; Total chlorophyll-a distribution.
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Problems in rural transformation in South Africa specifically in the land reform arena:

  • Authors: Antrobus, Geoffrey G , Fraser, Gavin C G , Tapson, D R
  • Date: 1998
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/143035 , vital:38195 , https://www.infona.pl/resource/bwmeta1.element.agro-article-dc77672d-7269-4641-bf99-605eaa5fe369
  • Description: Problems in rural transformation in South Africa specifically in the land reform arena
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Profile on POTWA

  • Authors: Post and Telecommunications Workers Association (Potwa)
  • Date: 1998
  • Subjects: POTWA
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/250717 , vital:52042
  • Description: POTWA was formed in August 1986 in Soweto after workers’ rejection of the liaison committees and workers’ councils tailored by management for black workers in the Department of Post and Telecommunications. Racist salaries also helped to mobilise workers into the union. At the launching congress, Potwa had already signed-up 10 000 members year, the union settled wage claims in nine regions.
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Raptor communities in hill habitats in south-eastern Zimbabwe

  • Authors: Davison, Bruce
  • Date: 1998
  • Subjects: Birds of prey -- Zimbabwe , Birds of prey -- Ecology -- Zimbabwe
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5751 , http://hdl.handle.net/10962/d1005438 , Birds of prey -- Zimbabwe , Birds of prey -- Ecology -- Zimbabwe
  • Description: The interrelationships between species composition, resource-use and availability, breeding and competition were studied in two hill habitat raptor communities in a conserved reserve and an unprotected communal land in Zimbabwe in 1995 and 1996. The conserved Lonestar Study Area (LSA) and the unprotected Communal Land Study area (CLSA) had 38 and 31 raptor species, high and normal diversities for the area sizes respectively. An estimated 147 pairs of 21 raptor species bred in 40km² in the LSA compared to only 26 pairs of 22 raptor species per 40km² in the CLSA. Six species (African Hawk Eagle Hieraaetus spilogaster, Black Eagle Aquila verreauxii, Crowned Eagle Stephanoaetus coronatus, Little Banded Goshawk Accipiter badius, Barn Owl Tyto alba,and Barred Owl Glancidium capense made up 69% of breeding raptors in the LSA, while African Hawk Eagles, Little Banded Goshawks, Barn Owls and Barred Owls made up 58% of the breeding raptors in the CLSA. The abundance of Black, Crowned and African Hawk Eagles in the LSA was linked to abundant hyrax, Heterohyrax brucei and Procavia capensis and juvenile bushbuck Tragelaphus prey, and the high reproduction rates of Natal Francolin Francolinus natalensis (0.7 per ha when not breeding). Little Banded Goshawk and Barn Owl abundances were linked to their ability to change prey preferences according to prey availability. A fairly high rate of breeding attempts by eagles in the LSA in both years (60 - 76% of all pairs per year)was probably also linked to prey abundance, Most breeding failures were predator related, and were more common in areas of relatively low nesting densities indicating lower parental vigilance there. High eagle breeding densities were associated with small mean territory sizes in the LSA (7.7 - 10.7km² for the main eagle species). Eagles in the LSA usually nested closer to another eagle species than a conspecific, resulting in regular distributions of nests and no territory overlap within species. Differences in daily flight activity of eagles in both study areas, and in the onset of breeding between LSA eagles probably reduced interspecific aggression. Interspecific competition food and nest sites amongst LSA eagles was possibly lessened by slight ditferences in resource selection. Raptor resources were mostly unaffected by human activities in either study area during the study period. Differences in the raptor communities were probably as a result of natural habitat differences. The CLSA raptors potentially face resource loss through forest clearing and hunting. An expansion of the present CAMPFIRE program will protect the CLSA raptors.
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Regionalism in marine biology: the convergence of ecology, economics and politics in South Africa

  • Authors: McQuaid, Christopher D , Payne, A I L
  • Date: 1998
  • Language: English
  • Type: Article
  • Identifier: vital:6938 , http://hdl.handle.net/10962/d1011960
  • Description: The South African coast includes biogeographic provinces which are quite distinct in their abilities to sustain exploitation and in the types of exploitation they experience. As a result, no single region can act as a model for the management of living resources around the entire coast. Instead, appropriate management must rest on regionally based research. Past research in marine biology focused on the west coast with much less attention being given to the east and south coasts, where non-commercial, subsistence-level fisheries predominate. A partial decentralisation of research focus is essential. This requires commitment from national-level research bodies and some certainty about at least medium-term funding. This paper addresses the convergence of ecology, economics and politics in South Africa and illustrates the direct relevance that fundamental or basic research can have to socioeconomic problems. Recruitment of the resource; Geographical variation in biological processes; State of research policy; Promise of regulations.
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Removal and recovery of heavy metals from synthetic solutions and electroplating effluents using yeast and the water fern Azolla filiculoides

  • Authors: Zhao, Ming
  • Date: 1998
  • Subjects: Heavy metals -- Environmental aspects Azolla filiculoides -- Biological control Aquatic weeds -- Biological control Yeast Metal ions Yeast fungi -- Biotechnology Cations
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4001 , http://hdl.handle.net/10962/d1004061
  • Description: The aims of the project were twofold. The initial objective of the study, based on previous results, was to develop an economically viable methodology for immobilizing yeast cells for the treatment of heavy metal-laden waste water. The non-viable yeast cross-linked by 13% (w/v) formaldehyde/1N HNO₃ exhibited satisfactory mechanical strength and rigidity in a continuous-flow column operation. No apparent disruption of the biomass after repeated use was observed. The cost of immobilizing 1kg dry yeast pellets was estimated at less than US$I. Zn uptake capacity of FA-cross-linked pellets, on batch trials, remained similar to that of raw yeast, reflecting that the immobilizing procedure did not hinder its metal removing capacity. In column studies, cation metals were effectively removed by the yeast pellets from aqueous solution at natural pHs, and then recovered completely by washing the pellets in situ with O.1M HCl. The recovered metals were concentrated in such small volumes that recycling or precipitation of them was facilitated. The metal uptake capacity of the regenerated biomass remained constant in comparison with cycle 1, indicating that reuse of the yeast would be possible. In the case of Cr⁶⁺, a gradual breakthrough curve of Cr in the column profile was noted, with a simultaneous reduction of Cr⁶⁺ to Cr³⁺. However, Cr⁶⁺ in the effluent can be markedly minimised either by accumulation onto the biomass or reduction to its trivalent form. Desorption of bound Cr⁶⁺ with either alkali or salt could not accomplish the regeneration of the biomass. A combination of reduction and desorption with FA/HNO₃ appeared promising in regeneration of the saturated biomass at 4°C. The metal sorption capacities of the yeast pellets, on a batch or a fixed-bed system are relatively lower than that of documented sorbents. Apparently more of the yeast pellets would be required for treating a certain volume of waste effluent, than with other sorbents. Therefore Azolla filiculoides was examined as a suitable sorbent for this purpose. This constitutes the second part of the project. Azolla filiculoides, a naturally-abundant water fern, was screened for its metal sorption and recovering capacities, mechanical stability, flow-permeability and reusability. The azolla biomass appeared to have fulfilled the required mechanical criteria during the repeated sorption-desorption column operations. It is water-insoluble and appears flexible under pressure when rinsed with water. These characters are of crucial importance in a continuous-flow system since a column can be operated at high flow rates without apparent compact of the biomass and pressure loss. Therefore, immobilization of the biomass can be avoided. The sorption isotherm data, obtained from batch removal of Cr⁶⁺, showed that the sorption process was effective, endothermic and highly pH dependent. Considerable amounts of Cr⁶⁺ were accumulated at the optimum pHs of 2-2.5. Column sorption of Cr⁶⁺ at a low flow rate and pH of 2.5 showed optimum performance with a total Cr uptake of 50.4mg/g at 60% saturation of the biomass. Removal of Cr⁶⁺ from an electroplating effluent using an azolla column was deemed reasonably satisfactory, although the uptake declined slightly. Desorption of bound Cr⁶⁺ with various desorbents was incomplete, which resulted in a low regeneration efficiency of about 50%. However, removal and recovery of Cr³⁺ using the azolla column was than that of Cr⁶⁺. Desorption of Cr³⁺ from the spent biomass column was accomplished with the recovery of 80% using O.5N H₂SO₄, The regeneration efficiencies for Cr³⁺ removal were up to 90% and demonstrated that the biomass is reusable. Cation metal uptake capacities of azolla, obtained either from batch or column experiments, are reasonably high in comparison with other sorbents. The uptake of Ni or Zn ions from solution is pH dependent showing the optimum pH of around 6 to 6.5, under the current experimental conditions. The sorption kinetics for cation metals was rapid with about 80% of the bound Ni ions being taken up in the first 10 min. The character of rapid binding is extremely important in a column sorption process, especially on a large scale since it favours an optimum uptake of metals at high flow rates. The Ni or Zn uptakes in column sorption were not markedly affected when the flow rates were increased from 80mllh up to 800ml/h for the 5g biomass used. The cation heavy metals removed from waste effluents were recovered in a concentrated solution of small volume. The desorption of bound Ni and Zn ions from the saturated biomass was accomplished with either O.2N HCl or H₂SO₄ that resulted in recoveries of more than 95%. The metals recovered, in the case of Ni and Zn, are identical to that of plating agents ego nickel sulphate or chloride, so that recycling of the metals is possible. An effluent-free, closed loop of Ni or Zn treatment system was proposed, whereby the Ni or Zn ions can be recycled to the plating bath whilst the purified water is fed back to the rinse tanks. Ca and Mg ions, commonly present in the electroplating effluents, appeared to affect sorption of heavy metals by azolla when metal concentrations were relatively low, presumedly through its competitive binding for the shared sites on surfaces of azolla. The data obtained from column sorption of Ni and Zn follows the BDST model well, enabling the application of the model to predicting design parameters for scale-up of the biosorption column system. It is interesting that the values of metal uptake, expressed in molar quantities, obtained on respective single-metal solutions and the multiple metal system, are similar, implying that the mechanisms involved in the sorption of all metal cations are similar and that the binding sites on surfaces of azolla are probably shared by all cation metals. The surface of the biomass provides sites for metal binding estimated in the range of 0.45-0.57mmol/g, based on the current experiments. The biomass has a surface area of 429 m²/g and water retention of 14.3 ml/g. The functional groups on the surface of azolla were partially identified using chemical modification and metal binding comparison. Among the functional groups examined, carboxyl groups, provided by amino acids and polysaccharides, appeared to play an important role in metal cation binding. The infrared spectra of the samples support this conclusion.
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Reproductive behaviour of the skunk clownfish, Amphiprion akallopisos, under captive conditions

  • Authors: Haschick, Rory Dean
  • Date: 1998
  • Subjects: Anemonefishes -- Spawning , Amphiprion -- Reproduction , Fishes -- Reproduction , Hatchery fishes
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5316 , http://hdl.handle.net/10962/d1005161 , Anemonefishes -- Spawning , Amphiprion -- Reproduction , Fishes -- Reproduction , Hatchery fishes
  • Description: The objectives of the study were to determine whether or not behaviour could be used to predict spawning in Amphiprion akallopisos, and to document the behaviour of this species under various environmental conditions in captivity. The spawning behaviour of A. akallopisos was studied and quantified. Three behaviour patterns - belly touching, nest cleaning by the female and mutual nest cleaning (by the male and the female) were identified as predictors for spawning. The reproductive behaviour of A.akallopisos under three photoperiods was investigated. The photoperiods were: 14L:10D, 10hr15minL:13hr45minD and a natural photoperiod cycle condensed into three months. A. akallopisos maintained under 14 L:10D exhibited a significantly higher frequency and duration of chasing, nest cleaning and total interaction compared to fish kept under 10hr15minL:13hr45minD. A photoperiod of 14L:10D was selected for further studies. As manipulation of photoperiod did not induce spawning, GnRHa was administered to the fish in the diet at levels of 10, 20, 40 and 80 μg/kg BW. Control groups were fed untreated food. None of the dosages were successful in inducing spawning, or spawning behaviour in A. akallopisos. It is possible that the method of hormone application was not suitable for this species. It is also possible that behaviour may regulate blood hormone levels as opposed to endocrine status influencing behaviour. In the third trial, A. akallopisos was maintained with, and without sea anemones in order to determine whether or not anemone hosts are necessary for spawning. The presence of anemones did not induce spawning and A. akallopisos kept without anemones exhibited significantly more interactive behaviour than fish kept with hosts. Spawning of A. akallopisos at a later date without anemones suggests that anemones are not necessary for spawning in A. akallopisos. Light intensity was investigated as a cue for spawning. The reproductive behaviour of A. akallopisos was then studied under light intensities of 4.16 x 10¹⁵ quanta.sec⁻¹.cm⁻², 8.85 x 10¹⁵ quanta.sec⁻¹.cm⁻² and this intensity plus natural light. Spawning occurred mainly under 8.85 x 10¹⁵ quanta.sec⁻¹.cm⁻². Fish maintained under this light intensity exhibited significantly more of nest cleaning behaviour in terms of frequency and duration than fish maintained under low light intensity. A minimum light intensity of 8.85 x 10¹⁵ quanta. sec⁻¹.cm⁻² is recommended for conditioning of this species. This study can be of practical relevance to hatchery managers who can use the methods developed and record predictors for spawning in A. akallopisos and other Amphiprion species. In this way imminence of spawning may be estimated. Most importantly, the study also has academic merit as little work has been undertaken in this field. Although the observational method used in this study was adequate for the purposes of the investigation, future work of this nature should incorporate other methods of documenting gonadal development such as gonadal staging and GSI in order to obtain more conclusive results.
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Research cruise of the Scandinavian/South African Antarctic expedition, December 1997 to February 1998

Rhodes University Graduation Ceremony 1998

  • Authors: Rhodes University
  • Date: 1998
  • Language: English
  • Type: text
  • Identifier: vital:8132 , http://hdl.handle.net/10962/d1006777
  • Description: Rhodes University Graduation Ceremonies [at] 1820 Settlers National Monument Wednesday, 18 February 1998 at 6:00 p.m. [and] Friday, 17 April 1998 at 10:30 a.m., 18:00 p.m. [and] Saturday, 18 April 1998 at 10:30 a.m. , Rhodes University 1998 Graduation Ceremony City Hall, East London Friday, 8 May 1998 at 18:00 p.m.
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SACCAWU - Summer School

  • Authors: SACCAWU
  • Date: 1998
  • Subjects: SACCAWU
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/113880 , vital:33841
  • Description: The publication of this Green Paper is the first step taken by the Department of Labour in developing new legislation to regulate minimum employment standards in South Africa. The Department believes that the Basic Conditions of Employment Act (BCEA) 3 of 1933 and the Wage Act 5 of 1957 should be revised and replaced by a single law regulating statutory employment standards. This is needed to meet the country's social, political and economic goals as reflected in the Reconstruction and Development Programme (RDP) and adopted by the Government of National Unity. The purpose of the Green Paper is to promote a debate on the development of the law. It contains proposals and options for discussion. It also briefly describes important aspects of these Acts for people who may not be familiar with their contents. The Green Paper has been prepared by the Directorate: Minimum Standards of the Department of Labour which is responsible for enforcing the BCEA and the Wage Act. It does not represent an official government view. It has not been endorsed by the Cabinet. It awaits the outcome on certain issues of the Report of the Comprehensive Labour Market Commission. The Green Paper will be submitted to the social partners in the National Economic Development and Labour Advisory Council (NEDLAC) for consideration. It is published to obtain public comment and will be circulated to other government agencies to obtain their views. The Green Paper concentrates on the principles that will form the basis for the development of the new legislation. It draws the attention of the public and the social partners to aspects of the existing laws that often do not receive adequate attention.
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Sexual dimorphism and tail-length in widowbirds and bishopbirds (Ploeeidae: Euplectes spp.): a reassessment

  • Authors: Craig, Adrian J F K , Villet, Martin H
  • Date: 1998
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/442306 , vital:73974 , https://doi.org/10.1111/j.1474-919X.1998.tb04551.x
  • Description: No evidence for sexual selection in the evolution of tail‐length or wing‐length in widow birds and bishopbirds (genus Euplectes) was found when the methods used by previous authors were applied to a larger set of data. Nuptial tail‐length dimorphism scaled with body size dimorphism except in Euplectes progne, and interpopulation variation in taillength could be explained by genetic drift alone. Wing‐length appears to be under stabilizing selection and scales allometrically with body size, with no relation to tail‐length unless E. progne is included in the analysis.
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South African panorama: the novels of Daphne Rooke

  • Authors: Coetzee, Paulette June
  • Date: 1998
  • Subjects: Rooke, Daphne, 1914- -- Criticism and interpretation
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2222 , http://hdl.handle.net/10962/d1002265 , Rooke, Daphne, 1914- -- Criticism and interpretation
  • Description: This thesis covers Daphne Rooke's eight published "South African" novels: A Grove of Fever Trees, Mittee, Ratoons, Wizards' Country, A Lover for Estelle, The Greyling, Diamond Jo, and Margaretha de la Porte. It supports the recent revival of critical interest in Rooke, and argues for the continuing relevance of her work in post-apartheid South Africa. This study also broadens the scope of recent Rooke research by including lesser known works like The Greyling and Margaretha de la Porte in its analysis. Recent criticism has focused on Rooke's unusual blend of romance and realism. The first three chapters concentrate more on "realism", emphasising the depth and extent of Rooke's engagement with serious social issues. The novels are examined in terms of their handling of the themes of class (chapter one), race (chapter two) and gender (chapter three). The concluding chapter shifts in focus to "romance" and examines the question of generic_identity -- touching on Rooke's gothic, magical realist and "popular" qualities -within a consideration of the particular "South African-ness" of her work.
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Southern African Journal of Gerontology, volume 7, number 1, April 1998

  • Authors: Ferreira, Monica (editor) , Moller, Valerie , HSRC/UCT Centre for Gerontology
  • Date: 1998
  • Subjects: Gerontology -- South Africa , Older people -- Care -- South Africa
  • Language: English
  • Type: Text
  • Identifier: vital:8076 , http://hdl.handle.net/10962/d1012871
  • Description: [From Editorial] Each of the papers in this number of SAJG deals with dilemmas and issues in the matter of public and private care for older persons in southern Africa. Three papers deal explicitly with South Africa's social-security system·- specifically the old-age pension. Two papers deal with residential care models. And a sixth paper examines informal caregiving. In an expansive overview of public finance and ageing in South Africa, Van der Berg examines budgetary expenditure on the older population and places the magnitude and function of the social-pension system in perspective. The author briefly traces the historical evolution of the system. In a paper based on extensive archival research, Sagner details the history of the pension from 1920 to 1960 and shows that numerous contemporary pension-related issues are no different to issues of past decades. In her paper, Oakley examines the effects of recent changes in social-welfare policy on the residents and administrators of a home for marginalized older people in a remote South African town. She contends that new policy erroneously assumes that marginalized and historically disadvantaged older individuals are able to live self-sufficiently within the bosom of family - in a spirit of ubuntu. Ackermann and Matebesi report on a study of the experiences of carers of older family members in an African township and consider how these carers, who have few resources, could be assisted and supported in their care giving tasks. Mupedziswa describes the nature and functioning of an alternative residential care model in Zimbabwe - a cooperative living scheme specifically established to enable destitute and socially-impoverished older people to co-reside in a safe and mutually-supportive environment. Moller gives readers an insightful update and analysis of the January 1998 pension payment debacle in the Eastern Cape Province, when the payment of more than 600 000 pensioners was delayed because of provincial-government management errors. Finally, SAJG welcomes Wilson's announcement in a letter to the editor of the establishment of AFRIT A, whose aims are to promote and to co-ordinate linkages between training and research initiatives on ageing and policy structures in African countries.
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Southern African Journal of Gerontology, volume 7, number 2, October 1998

  • Authors: Ferreira, Monica (editor) , Moller, Valerie , HSRC/UCT Centre for Gerontology
  • Date: 1998
  • Subjects: Gerontology -- South Africa , Older people -- Care -- South Africa
  • Language: English
  • Type: Text
  • Identifier: vital:8077 , http://hdl.handle.net/10962/d1012911
  • Description: [From Editorial] Articles in this Special Issue on health and ageing in Africa come from a broad spectrum of disciplines and the articles reflect a wide range of topics. Three contributions deal with the maintenance of good health. Remaining active is a key component of successful ageing which minimizes the loss of functional independence in the elderly. An investigation of the role of gender in the analysis of gait of older people by Macfarlane, Nicholson and Muller provides important methodological information which may be applied in practical outcomes-based assessments. The development of a reliable tool to assess gait, as a measure of lower-extremity function, is thus pertinent. There is growing evidence that good nutritional status is an important determinant of optimal cognitive and physical functioning in older people and influences both quality of life and health status. In a study of institutionalized elderly women in Cape Town, Charlton, Joosen and Jaffer report a high prevalence of suboptimal vitamin C status. The authors make out a case for low-dose micro-nutrient supplementation in residents of homes for the aged, particularly in homes where a cook-chill catering system is operated. They suggest that ongoing nutritional assessment should be an integral part of the care of older residents. In keeping with the topic of nutrition, Walker, a prolific author on public health issues in Africa over the past 50 years, has contributed a guest column in which he addresses the nutrition-ageing paradigm from an epidemiological viewpoint. He highlights opportunities for high-quality research on the association between life-style factors and healthy ageing in the continent. Moving on to a specific form of health-care delivery, Makoni examines language practices in the care that is rendered to older residents of a Cape Town nursing home. He describes barriers in communication between nursing staff and residents from different ethnic backgrounds, which compromise the quality of care that is rendered and which may result in conflict and tension between staff and residents. In her article, Tlou evaluates a community-based programme in which older women who live in rural areas of Botswana are trained to educate members of their communities in the prevention of the spread of the HIV I AIDS virus. The findings demonstrate the benefits of targeting lay persons for health education activities in rural Africa and the utilization of older persons, in this case women, as a valuable resource. The special issue also includes two opinion pieces and an item which opens debate. In separate contributions, Wilson and Duodu examine challenges facing effective health-care service delivery systems for older persons in African countries and express their opinions in this regard. Wilson's suggestions for multidisciplinary specialist teams, including incontinence teams, nutrition teams and vision teams, and for the development of training for lay people to become generic " rehabilitation assistants," are examples of appropriate community-based African solutions to health service delivery needs of the older population. Duodo makes similar suggestions to those of Wilson, specifically regarding geriatric care service delivery in Ghana. He also highlights the common practice of traditional self-medication in rural-dwelling older Ghanaians. Readers are invited to comment on, and indeed to augment, the authors' opinions in Letters to the Editor. To date, very little work has been done in South Africa on biological aspects of ageing. In a short contribution on the free radical theory of ageing, Van Rensburg and Potocnik open debate on this topic. Once again, readers are invited to contribute to debate in this area in letters to the editor, for publication in the following number of the journal.
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Spatial and temporal variability in recruitment of intertidal mussels around the coast of southern Africa

  • Authors: Harris, Jean M , Branch, George M , Elliot, Bridget L , Currie, Bronwen , Dye, Arthur H , McQuaid, Christopher D , Tomalin, Bruce J , Velasquez, Claudio
  • Date: 1998
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/447579 , vital:74658 , https://www.ajol.info/index.php/az/article/view/154717
  • Description: Intensity of intertidal mussel recruitment was compared across a range of different spatial and temporal scales around the coast of southern Africa between June 1995 and October 1996. Comparison of the east and west coasts revealed significantly higher recruit densities on the west coast, corresponding to larger adult densities. This difference between the two coasts reflects biogeographic disparities in mussel species composition, growth rates and spawning intensities, oceanographic conditions and productivity. Significant spatial variations in recruitment were recorded between regions 100–1000 km apart and between localities 1–25 km apart. Results suggest that the influence of dispersal processes on recruitment patterns acts at a relatively small scale, and may affect the distribution and abundance of adults among shores only a few kilometres apart.
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Successes and challenges of the NUMSA Gender Committee

  • Authors: National Union of Metalworkers of South Africa
  • Date: 1998
  • Subjects: Uncatalogued
  • Language: eng
  • Type: text , pamphlet
  • Identifier: http://hdl.handle.net/${Handle} , vital:32406
  • Description: This session will try to cover policies adopted at the Congress and Central committee and will be divided in the following sections: collective bargaining, campaigns, gender structures/coordination, education, recommendations for discussion.
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Surface distribution of microphytoplankton of the south-west Indian Ocean along a repeat transect between Cape Town and the Prince Edward Islands

  • Authors: Froneman, P William , Pakhomov, Evgeny A , Meaton, V
  • Date: 1998
  • Language: English
  • Type: text , Article
  • Identifier: vital:6933 , http://hdl.handle.net/10962/d1011953
  • Description: Surface chlorophyll-a (chl-a) concentrations, microphytoplankton (>20 μm) species composition and distribution along a repeat transect between Cape Town and the Prince Edward Islands were investigated in early austral autumn (April/May) 1996. Samples were collected at approximately 30 nautical mile intervals for the analysis of size-fractionated chl-a and the identification and enumeration of microphytoplankton species. Peaks in total chl-a (>1 μg 1 [superscript -1]) were recorded at the Subtropical Convergence (STC), at the Sub-Antarctic Front (SAF) and in the waters surrounding the Prince Edward Islands. In addition, a minor peak in chl-a concentration was recorded in the continental shelf waters. At stations where elevated chl-a concentrations were recorded, microphytoplankton generally formed a substantial contribution (-10%) to total chlorophyll. Outside these regions, total chlorophyll concentrations were lower (<0.9 μg 1 [superscript -1]) and almost entirely dominated by nano- and picophytoplankton, which contributed >95% of the total. Microphytoplankton species composition along both transects were dominated by chain-forming species of the genera Chaetoceros (mainly C. neglectum, C. peruvianus and C. constrictus), Nitzschia spp. and Pseudoeunotia doliolus. Cluster and ordination analysis based on species composition identified five distinct microphytoplankton assemblages, which were closely associated with the different water masses in the region between Cape Town and the Prince Edward Islands. The microphytoplankton species composition and biogeographic zones identified during this investigation are in general agreement with similar studies conducted in the south-west Indian Ocean during the austral summer, which suggests that there are little seasonal trends in both the microphytoplankton species composition and biogeographic zonation.
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Symplastic solute transport and avocado fruit development : a decline in cytokinin/ABA ratio is related to appearance of the Hass small fruit variant

  • Authors: Moore-Gordon, Clive S , Cowan, Keith A , Bertling, Isa , Botha, Christiaan E J , Cross, Robin H M
  • Date: 1998
  • Language: English
  • Type: Article
  • Identifier: vital:6525 , http://hdl.handle.net/10962/d1005959
  • Description: Studies on the effect of fruit size on endogenous ABA and isopentenyladenine (iP) in developing avocado (Persea americana Mill. cv. Hass) fruit revealed that ABA content was negatively correlated with fruit size whilst the iP/ABA ratio showed a linear relationship with increasing size of fruit harvested 226 d after full bloom. The effect of this change in hormone balance on the relationship between symplastic solute transport and appearance of the small fruit variant was examined following manipulation of the endogenous cytokinin (CK)/ABA ratio. Application of ABA caused seed coat senescence and retarded fruit growth but these effects were absent in fruit treated with equal amounts of ABA plus iP. Thus, the underlying physiological mechanisms associated with ABA-induced retardation of Hass avocado fruit growth appeared to be inextricably linked to a decline in CK content and included: diminution of mesocarp and seed coat plasmodesmatal branching, gating of mesocarp and seed coat plasmodesmata by deposition of electron dense material in the neck region, abolishment of the electrochemical gradient between mesocarp and seed coat parenchyma, and arrest of cell-to-cell chemical communication.
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Telkom Substantive Negotiations

  • Authors: CWU
  • Date: 1998
  • Subjects: CWU
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/175666 , vital:42604
  • Description: During the financial presentation of the company, the impression was created that the attributable income is unrealistic due to the fact that capital expenditure for the first six months were way below budget.
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