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AES-24 and MIDINet-A Comparative Study of Their Object Models and Implementations

  • Authors: Foss, Richard , Klinkradt, Bradley
  • Date: 2000
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/427390 , vital:72435 , https://www.aes.org/e-lib/browse.cfm?elib=9220
  • Description: AES-24 and MIDINet object models have been used to create corresponding implementations. Both implementations utilize a network of IBM PCs running the Windows operating system. The transport protocol in each case is the Internet Protocol (IP). The object models of the two systems have some differences and similarities that have an impact on the application protocols. Arising from this study are pointers toward the incorporation of MIDI transport into the AES-24 framework.
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  • Date Issued: 2000

Africa Unity

Ah! les hommes

Ammonia removal from water by ion exchange using South African and Zambian zeolite samples

  • Authors: Mwale, Monica
  • Date: 2000
  • Subjects: Ammonia -- Toxicology , Water -- Purification , Zeolites , Ion exchange
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5215 , http://hdl.handle.net/10962/d1005058 , Ammonia -- Toxicology , Water -- Purification , Zeolites , Ion exchange
  • Description: One problem of intensive fish culture systems is the progressive build-up of toxic wastes such as ammonia. The possibility of improving aquaculture water quality using two kinds of zeolite is discussed. Zeolites are alumino-silicates whose framework allows them to exchange cations. Ion exchange has been demonstrated to be competitive with other methods of ammonia removal due to the high selectivity for ammonia exhibited by zeolite materials. In this study an unknown Zambian zeolite (identified as laumontite by X-ray diffraction techniques) and Pratley clinoptilolite (a South African zeolite) were tested under laboratory conditions and in a fresh water recirculating system. Ammonia cation exchange capacities (CEC) and suitable application rates for efficient water treatment were determined using the batch and column ion exchange procedures. Estimated ammonia uptake, the most important criterion used to assess performance of zeolite filters was strongly influenced by zeolite type, particle size, pre-treatment, regeneration and ion exchange method used. Statistical analysis showed significant differences in average ammonia CEC values between clinoptilolite (14.94 mg g⁻¹) and laumontite (2.77 mg g⁻¹), with the former displaying a higher Na⁺ ® NH₄⁺ exchange rate especially in the early reaction stages. This difference accords with the higher purity of clinoptilolite, 47% as opposed to 4.7% for laumontite, which makes it a better zeolite for ammonium removal. CEC increased linearly as particle size of the clinoptilolite was reduced resulting in a linear regression model (y = 18.29 – 3.704 x; r² = 74%). Pre-treatment of clinoptilolite using 1N NaCl significantly improved the ammonia CEC of clinoptilolite. Overall performance of both the batch and column methods achieved after regeneration (18.3 mg g⁻¹) was 25% higher than the estimated CEC values (13.0 mg g⁻¹) for the unregenerated samples of clinoptilolite. Comparison of CEC estimates using Pratley clinoptilolite, showed that average batch CEC estimates were significantly lower than the column method estimates. The average ammonia CEC values estimated in a fresh water recirculating system (5.80 mg g⁻¹ and 4.12 mg g⁻¹ for the 0.7-1.0 and 1.0-1.4 mm particle sizes, respectively) were significantly lower than the column and batch estimates for the same particle sizes (P < 0.05). Some nitrite (NO₂) and nitrate (NO3) build up was experienced probably due to the growth of autotrophs in the filters. Mass balance of nitrogen (N) for the three treatments of the fish trial (0.7-1.0 mm, 1.0-1.4 mm and the control treatment that had no zeolite in the filter) indicated that less that 10% of the N was retained for growth. It was found that 60% of the NH₄-N present associated with the soluble N was available for absorption by the zeolite filter or biological nitrification and that a total of approximately 22% of NH₄-N available was absorbed by clinoptilolite. The results indicate that the rate of nitrification can be deductively estimated by allowing a zeolite filter to become a biological filter. It is concluded that water treatment by ion exchange using natural zeolites, provides a reliable and efficient method for ammonia removal and appears to be a viable supplementary water treatment method for fresh water systems.
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  • Date Issued: 2000

An analysis of the effects of marriage, divorce and death on the child maintenance obligation in South African law with some comparative perspectives

  • Authors: Clark, Brigitte
  • Date: 2000
  • Subjects: Child support -- Law and legislation -- South Africa Divorce -- South Africa Marriage -- South Africa Death
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:3669 , http://hdl.handle.net/10962/d1003184
  • Description: This thesis analyses the law of child maintenance in South Africa with particular reference to the effects of marriage, death and divorce on such an obligation. In the introductory section, the types of South African family are demographically and statistically sketched, from a socio-legal perspective with some reliance on interdisciplinary research to assess the prevalence of the AID/HIV epidemic in South Africa, and the effects of poverty and ageing on the incidence of marriage and death. In the second part of the thesis, the parental child maintenance obligation is analysed in the common law context. The effects of serial marriage and arificial conception are also analysed with regard to their effect on the concept of biological parent. The nature and definition of parenthood is examined and the diverse and fluid nature of parenthood in South African society is stressed, particularly in relation to children's welfare. One of the aims of the thesis is to indicate how parenthood refers to a fluid set of social practices which are both biologically and culturally situated and thus have a complex effect on the maintenance obligation. The procedural problems of enforcement are also analysed in the light of recent amendments to the law in terms of the Maintenance Act 99 of 1998 (not yet in force) and some further proposals for reform in this area are proposed. The third part of the thesis examines the state obligation to maintain children, especially in the light of the state's commitments to children in terms of the Constitution of the Republic of South Africa Act (l08 of 1996) and its international commitments in terms of the United Nations Convention on the Rights of the Child which was ratified by the South African government on 16 June 1995. In the fourth part of the thesis, there is some comparative analysis, firstly, of the procedural law reforms proposed in Namibia as a result of detailed research done there. Secondly, alternative methods of assessing and enforcing child maintenance obligations in Australia and England are examined and briefly assessed in relation to their possible implementation and efficacy in a South African context. Finally, the thesis concludes with an overall synopsis of the position in this country and some proposals for reform in the light of the international and constitutional commitments of the state.
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  • Date Issued: 2000

An annotated checklist of the species of the Labroid fish families Labridae and Scaridae

  • Authors: Parenti, Paolo , Randall, John E, 1924-
  • Date: 2000
  • Language: English
  • Type: Text
  • Identifier: vital:15028 , http://hdl.handle.net/10962/d1019894 , ISSN 0073-4381 , Ichthyological Bulletin J.L.B. Smith Institute of Ichthyology; No. 68
  • Description: An annotated checklist of the species of the fish families Labridae and Scaridae is presented; 541 valid species are recognized, including 68 genera and 453 species of labrids and 10 genera and 88 species of scarids. Thirty undescribed species of wrasses and two undescribed parrotfish species are also included. A list of nominal species is given, with their present assignments; nominal species of uncertain status are placed as incertae sedis and listed separately. A list of nomina nuda is also provided. The valid genera and species are listed alphabetically, with their synonyms and distributions. Examination of the original descriptions and type material (when extant) of previously unplaced nominal species of labroid fishes led to identification of 69 new synonyms. The generic names Artisia de Beaufort, 1939 and Emmeekia Jordan & Evermann, 1896 are here recognized as new synonyms of Halichoeres Ruppell, 1835. For the Labridae, 65 new synonyms of valid species are listed. Labrus psittaculus Richardson, 1840, a valid species of Pseudolabrus, is a primary homonym of Labrus psittaculus Lacepede, 1801; the next available name for this species is Labrichthys rubicunda Macleay, 1881 and the new combination Pseudolabrus rubicundus is proposed. The following new combinations are included: Pseudojulis inornatus Gilbert, 1890 is a valid species of Pseudojuloides; Xyrichtys perlas Wellington et al., 1994 is a valid species of Novaculichthys. For Scaridae, Sparus abildgaardi Bloch, 1791 is a senior synonym of Sparisoma chrysopterum (Bloch & Schneider, 1801), but a request of the International Commission has been made to reject abildgaardi in order to conserve S. chrysopterum; and Scarus visayanus Herre, 1933 is a new synonym of Scarus tricolor Bleeker, 1847. Pseudoscarus microcheilos Bleeker, 1861 is a synonym of Chlorurus strongylocephalus (Bleeker, 1854). , Rhodes University Libraries (Digitisation)
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  • Date Issued: 2000

An appraisal of the production and utility of digital atlases in Africa: a case study of Swaziland

  • Authors: Pettit, Louise Manda
  • Date: 2000
  • Subjects: Swaziland Atlases , Digital mapping , Geographic information systems , Cartography -- Data processing , Cartography -- Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4816 , http://hdl.handle.net/10962/d1005490 , Swaziland Atlases , Digital mapping , Geographic information systems , Cartography -- Data processing , Cartography -- Africa
  • Description: This research will appraise the production and utility of digital atlases in an African context, using personal experience gained through the production of a digital atlas for Swaziland, the opinions obtained from other producers of African digital atlases and relevant literature. Since the 1950s, decision makers and researchers have viewed information as a powerful contributor to national development. Over the past thirty years, developed countries have increased the efficient collation and dissemination of geographic information through the utilization of the digital environment. The development of Geographic Information Systems (GIS) has increased the range of applications attainable in digital mapping projects. Applications have ranged from resource inventories to the monitoring of environmental degradation, crime patterns and service provision. The patchy history of data collection, analysis and mapping in Africa, has had a limiting effect on the ability of countries to identify, plan and control their resources efficiently. Despite the desire to automate the mapping process and reap some of the planning benefits evident in the developed world, Africa has not succeeded in mobilising full technological potential. Political instability, poor infrastructure, the absence of national policy guidelines, and a lack of skilled manpower are some of the issues which have limited utilization. Despite many of the hurdles faced by African countries, automated mapping and analysis technologies are still being pursued. The role of computers in the utilisation of data has become apparent through several means, one of which is the digital atlas. Analytical functions in many of these products allow situation modelling and provide superior graphic displays in comparison to their paper counterparts. Several African countries have embarked on the development of national digital databases and in some cases have produced digital national atlases. The potential to improve resource utilization, service provision and land use planning using these atlases, does exist. The production and utility of these atlases in an African context, however, needs closer assessment. "Computers don't clothe, don't cure, don't feed. Their power begins and ends with information. Their usefulness is therefore strictly linked to the ffectiveness of the information" (Gardner,1993:16).
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  • Date Issued: 2000

An assessment of the monkfish resource of Namibia

  • Authors: Maartens, Lima
  • Date: 2000
  • Subjects: Lophius -- Namibia Lophius
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5231 , http://hdl.handle.net/10962/d1005074
  • Description: Two monkfish species are caught off the coast of Namibia. These are Lophius vomerinus Valenciennes (1837) and L. vaillanti Regan (1903). L. vomerinus is the more abundant of the two and contributes approximately 99% to the total Namibian monkfish landings. The Namibian monkfish fishery is one of the largest and most valuable of its kind in the world. Two fishing fleets harvest the resource, viz. the monkfish and sole fleet and the hake directed fleet. In 1998 and 1999, monkfish were also harvested by one gillnet vessel that had an experimental right. In this study, the biology, abundance and exploitation patterns of monkfish were investigated and used as inputs into a stock assessment framework as a contribution towards the development of a management procedure for this species. Ground and sectioned otoliths and sectioned illicia were used to age Lophius vomerinus. The illicia provided more precise estimates of age, and growth was subsequently modelled using these age estimates. Growth in length and weight was best described by the threeparameter specialised von Bertalanffy model as Lt (cm TL) = 72.29 (1-e⁻°·¹⁴⁽t⁺°·³°⁾) and Wt (kg) = 3.96 (1-e⁻°·¹⁸⁽t⁺°·¹°⁾)²·⁹⁹ for males, and Lt (cm TL) = 111.98 (1-e⁻°·°⁸⁽t⁺°·³⁶⁾) and Wt (kg) = 6.92 (1-e⁻°·¹⁸⁽t⁻°·⁶⁴⁾)³·°³ for females. L. vomerinus is a slow-growing species with a life span in excess of 10 years. Reproductive activity was shown to occur throughout the year, with a slight peak during the winter months. The adult sex ratio of fish > 37 cm TL was biased towards females. Length-at-50% sexual maturity was attained at 32.1 cm TL for females and 23.7 cm TL for males. The rate of natural mortality was estimated at 0.15 year⁻¹, while fishing mortality rates during the 1970s, 1980s and 1990s were estimated at 0.01 year⁻¹, 0.04 year⁻¹ and 0.14 year⁻¹, respectively. Gillnetting for monkfish (300 mm stretched mesh) was highly efficient with a moderate bycatch of around 20% during the two years of operation. The main bycatch species were red crab, spider crab, squalid sharks, rays and Cape and Deep-water hake. The mean length of the monkfish caught in gillnets (67 cm TL) was significantly larger than the monkfish landed by the trawlers (38 cm TL) and less than 1% of immature fish were landed. Gillnet catch-per-unit-effort for monkfish fluctuated between 0.03 and 0.67 kg.day⁻¹.50 m net panel⁻¹, with a soak time of between one and sixteen days. More than 50% (by weight) of monkfish landed by monkfish and sole trawlers, consisted of fish below 36 cm TL. There was a significant increase in catches of juvenile monkfish during 1997 and 1998 in comparison to the period 1994 to 1996. Various types of rigid sorting grids were tested to release juvenile monkfish below 32 cm TL. Five grid designs were tested. These included an “Ex-it” grid with horizontal bars spaced at 55 mm, single grids with vertical and horizontal bars spaced at 55 mm and grids with circular openings of 110 and 168 mm in diameter. The most efficient design was the grid with circular openings of 110 cm in diameter, which ensured the escape of 66% of monkfish smaller than 31 cm TL. However, studies need to be undertaken to quantify the survival of released fish and to test the feasibility of using grid sorters on commercial monkfish and sole trawling gear. The monkfish resource was assessed by means of length cohort analyses, the Thompson and Bell predictive model and by way of a deterministic age-structured production modelling approach. The length cohort analysis models were sensitive to the rate of natural mortality and insensitive to changes in the terminal fishing mortality rate. These biases may, however, not be serious provided that estimates of abundance are used to reflect relative changes. Fish ranging between 26 and 59 cm TL are the most heavily exploited. The Thompson and Bell model predicted that the monkfish resource is exploited above MSY -levels and a reduction of approximately 40% in fishing effort would provide a higher yield. Yield-per-recruit ranged between 10 000 and 14 000 tonnes. Results should, however, be treated with caution, as the condition of steady state was not satisfied. The age-structured production model was tuned using trends in catch-per-unit-effort data, estimated by Generalised Linear Modeling, as well as relative abundance indices calculated from hake biomass surveys. The model was found to be sensitive to both the ‘steepness’ parameter h and estimates of natural mortality. The ‘depletion’ level of the monkfish resource is currently estimated to be 49%. Estimated coefficients of variation were high (> 63%) due to the lack of a consistent trend within the abundance indices to tune the model. Overall productivity of the monkfish resource was estimated to be approximately 16%, similar to other southern African demersal resources. Results of the risk analyses suggest that catches in excess of 7 000 tonnes may be unsustainable and that catches of 5 000 or 6 000 tonnes would decrease the risk of stock collapse and possibly lead to a recovery in the stock. Monkfish management strategies were reviewed and these were considered in relation to the results of this study. The following management recommendations were made: to follow the precautionary approach and implement a total allowable catch for monkfish; to implement rigid sorting grids as these would be the most appropriate way in which to reduce catches of juvenile monkfish; to restrict soak time, depth of operation and implement means to reduce ‘ghost fishing’ by gillnetting and finally, to develop a management procedure for Namibian monkfish with the main objective being the sustainable exploitation of the resource.
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  • Date Issued: 2000

An empirical formula for estimating the water use of Scaevola plumieri

  • Authors: Peter, Craig I , Ripley, Bradford S
  • Date: 2000
  • Language: English
  • Type: Article
  • Identifier: vital:6530 , http://hdl.handle.net/10962/d1005971
  • Description: Transpirational water loss of Scaevola plumieri (L) Vahl. (= Scaevola thunbergii Eckl. & Zeyh.) (Goodeniaceae), a dune pioneer plant along the eastern and southern coasts of South Africa, was measured over a wide range of atmospheric conditions and related to the atmospheric vapour pressure deficit (VPD). A plot of leaf transpiration rate (E) against VPD yielded a curvilinear relationship (r[sup 2] = 0.88, P = 0.000). As both leaf and canopy E were found to be closely coupled to atmospheric conditions, this correlation was used to calculate canopy E for entire days. The bulk volumes of water transpired per day were related to the mean daily temperature as recorded at a nearby weather station and were strongly related (r2 = 0.71, P = 0.0037). This correlation allowed the bulk volume of water transpired by one square metre of a S. plumieri-covered dune to be calculated on a daily basis for an entire year. Transpirational losses (566 litres) in 1997 were then compared with rainfall (539 litres), indicating that rainfall was perhaps insufficient to support the plants that year. Similar deficits were calculated for 1996, suggesting that plants were possibly reliant on water stored in the sand or taped ground water. This species showed an unusual positive response of increasing leaf conductance to increasing VPD over the range 0-3 kPa.
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  • Date Issued: 2000

An estimation of the standing stock and population structure of Upogebia africana (Crustacea: Thalassinidae) in the Knysna Estuary

  • Authors: Hodgson, Alan N , Allanson, Brian R , Cretchley, Robyn
  • Date: 2000
  • Language: English
  • Type: Article
  • Identifier: vital:6923 , http://hdl.handle.net/10962/d1011907
  • Description: Within the Knysna Estuary Upogebia africana has an extensive distribution from north of Leisure Isle to the Red Bridge, occupying 62% of the available intertidal zone. Six sites were surveyed within the above distributional range. U. africana was found from the high-water level (Spartina zone) to the shallow subtidal zone (to about 1.5 m depth). The density, biomass and population structure of the mud prawns were found to be highly variable within the estuary. Only small animals (carapace length –× = 10.9 mm) were found in the upper estuary at the Red Bridge. Although large animals were present, the Invertebrate Reserve had a low density and biomass of U. africana (– × = 11.7 m–2; 3.9 g.m–2 dry weight). By contrast a relatively inaccessible centre mud bank (Oyster Bank) in the middle reaches of the estuary had much larger populations (–× = 176.5 m–2; 65.3 g.m–2 dry weight). This site is, therefore, a natural mud prawn reserve. Within the intertidal zone, mud prawn density (74–76 m–2) and biomass (26–27 g.m–2 dry weight) was usually greatest in the Spartina and lower Zostera zones. Sex ratios throughout the estuary did not deviate significantly from 1:1.
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  • Date Issued: 2000

An evaluation of a strategy of lean manufacturing as a means for a South African motor vehicle assembler to achieve core competence

  • Authors: Maritz, Louis Wiehahn
  • Date: 2000
  • Subjects: Automobile industry and trade -- Management , Automobile industry and trade -- South Africa , Manufacturing industries -- Management
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:10834 , http://hdl.handle.net/10948/26 , Automobile industry and trade -- Management , Automobile industry and trade -- South Africa , Manufacturing industries -- Management
  • Description: South African businesses are facing unforeseen opportunities and threats following the country’s remarkable political transformation that culminated in its first non-racial, democratic elections in April 1994 (Krüger, 1997: 138). The objective of this paper was to understand what core competences a South African motor vehicle assembler requires to survive this era of declining protectionism and increasing competition. It is argued in this paper that organisations that want to compete with the best in the world market needs to adopt lean manufacturing principles. This paper is concerned with the core competences of an organisation and how an organisation identifies and utilises these in order to become a lean enterprise. The qualitative research method was identified as the most appropriate for the study. Two methods of data collection were used i.e. interviews with senior and middle management and a detailed literary study on the subject. The senior management interviews were aimed at identifying what they perceived to be the core competences a motor vehicle assembler requires in order to be a world-class lean manufacturing enterprise. The literary study was the base for the understanding of core competence and lean manufacturing. Finally, a second round of interviews with middle management was conducted to obtain clarity on the perceived role of middle management in the selected organisation’s quest to be a lean manufacturing concern. This paper concludes that if an organisation wants to survive it needs to identify and assess its core competences. These competences need to be developed or discarded in the organisation’s aims to be a lean manufacturing enterprise by eliminating all forms of non-value added activity. The programmes or projects that the selected organisation embarked on were primarily driven from the top down, placing middle management in the centre with the resistance coming from the lower levels in the organisation. Middle management should be given the necessary tools to overcome the resistance and assist the company to make smooth transitions.
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  • Date Issued: 2000

An evaluation of IMF structural adjustment programmes : lessons for South Africa

  • Authors: Berolsky, Nuno Goncalo
  • Date: 2000
  • Subjects: International Monetary Fund , International Monetary Fund -- Developing countries , Structural adjustment (Economic policy) -- Developing countries , South Africa -- Economic policy
  • Language: English
  • Type: Thesis , Masters , MSocSc
  • Identifier: vital:935 , http://hdl.handle.net/10962/d1002668 , International Monetary Fund , International Monetary Fund -- Developing countries , Structural adjustment (Economic policy) -- Developing countries , South Africa -- Economic policy
  • Description: The mixed results of International Monetary Fund structural adjustment programmes in less developed countries are a major motivation for this research. Explanations must be advanced as to what may inhibit the success of such programmes. South Africa has often found itself in a precarious position- with a deteriorating balance of payments, a position similar to other countries that have accepted IMF loans. Furthermore, South Africa undertook an IMF loan in 1993. Financial support from the IMF incorporates structural adjustment programmes. These may include measures such as tighter monetary policy, reduction in the budget deficit, exchange rate devaluation and ceilings on domestic credit with increased interest rates (Ferguson, 1988). These policies illustrate the principle of ‘conditionality,’ whereby access to further loans is conditional on certain criteria being met, such as reduced budget deficits and inflation rates. The principle of conditionality has met with a great deal of criticism. Bacha (1987) and Dell (1982) argue that these aggregate demand-reducing conditions more often than not stagnate domestic economies, worsening the balance of payment and result in programme breakdowns. Essentially, they refer to the IMF conditions as ‘unrealistic.’ The IMF denies this, arguing that shortfalls are mainly due to a lack of political commitment to carry out its conditions (Winters, 1994). This issue of conditionality will be examined in detail, using three specific case studies. The aim of this study is to examine the characteristics of Brazil, Mexico and Zambia to see whether or not the IMF programmes were successful. Guidelines will be established for South African policy from these case studies. South Africa is trying to adjust to the competitiveness of the international economy. At the same time, the need for reconstruction and development exerts increasing pressures on the balance of payments. Guidelines are established for a successful economic adjustment for South Africa. The research concludes that South Africa is certainly in line for a successful transformation. The rigidities are not as extensive as has been the case in Brazil and Zambia. Institutionally, South Africa is sound. However there are still challenges in this area, such as export diversification and economic stability to attract foreign investment.
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  • Date Issued: 2000

An evaluation of policies for attaining excellence in service delivery in the Port Elizabeth municipality

  • Authors: Binza, Mzikayise Shakespeare
  • Date: 2000
  • Subjects: Customer services -- Quality control , Customer services -- Management
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:10777 , http://hdl.handle.net/10948/d1006186 , Customer services -- Quality control , Customer services -- Management
  • Description: This dissertation is based on the assumption that the Port Elizabeth Municipality should deliver essential services effectively, efficiently and economically so as to attain excellence in service delivery. The essential services dealt with in this study are electricity; refuse collection; sewerage; and water services. Attaining excellence in service delivery will lead the Port Elizabeth Municipality to improve and sustain the quality of life of the local inhabitants. The primary objectives of this dissertation include, inter alia: An historical analysis of delivery systems of the former government prior to 1994, which provides the primary reasons and purposes of delivery systems, and the effects on the Port Elizabeth Municipality. Reformation and transformation of South African local government since 1994, with particular reference to the Port Elizabeth Municipality. A normative model for service delivery, which is designed to accelerate service delivery in the local spheres of government, with special reference to the Port Elizabeth Municipality as the locus of this study. The nature, extent and evaluation of the existing service delivery by the Port Elizabeth Municipality from 1994 to 1999. An empirical survey is conducted in the form of questionnaires to the directors, heads of departments, senior managers, as well as councillors. Approaches and strategies for attaining excellence in service delivery, which include, inter alia: a government-business paradigm and an equilibrium approach. Lastly, a number of recommendations are made and conclusions are drawn based on the findings of the empirical survey in order to deliver essential services equitably, efficiently, effectively and economically to attain excellence in service delivery in the Port Elizabeth Municipality.
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  • Date Issued: 2000

An evaluation of recirculating artificial stream designs for acute toxicity testing using two South African Ephemeroptera species exposed to sodium sulphate

  • Authors: Binder, Markus
  • Date: 2000
  • Subjects: Water -- Pollution -- Toxicology , Toxicology -- Research , Aquatic organisms -- Effect of water pollution on , Sodium sulfate , Mayflies
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5690 , http://hdl.handle.net/10962/d1005376 , Water -- Pollution -- Toxicology , Toxicology -- Research , Aquatic organisms -- Effect of water pollution on , Sodium sulfate , Mayflies
  • Description: Three artificial stream designs, termed Large Artificial Stream Units (LASUs), Raceways, and Channels, at two major scales (1700 L, 12.5 L and 20 L recirculated volume) were developed at the Institute for Water Research, Rhodes University, Grahamstown, in order to explore the possibilities of using indigenous rheophilic macroinvertebrates in routine toxicity tests. This study compared these systems, using 96h-EC50 values from sodium sulphate toxicity tests as the experimental response. Two local Ephemeroptera (Leptophlebiidae: Adenophlebia auriculata Eaton, and Baetidae: Afroptilum sudafricanum Lestage) were evaluated for their suitability in routine toxicity tests; and the possible effects of elevated salinity levels in South African rivers on the test species were assessed. Two sets of experiments with each mayfly species were conducted, following an unreplicated regression design. Dechlorinated tap water was used as the water source. Experiments in the Channels were repeated to determine experimental variability. Results were compared statistically by testing for overlap of 95% confidence limits (95%Cls) of EC50 values. The differences between A. auriculata EC50 values in the different systems were statistically significant (no overlap of 95%CLs), but they were not more variable than has been considered normal for biological systems (Coefficient of variation 20.1 %; ratio of greatest EC50 / smallest EC50 1.63). The differences were not related to the scale or the average current velocity characteristic of each stream design (average current velocity LASUs - Raceways - Channels 0.090 - 0.083 - 0.038 m/s). The Channels proved to be most efficient with regard to practical performance as they are portable and easily transportable, user-friendly, reliable, splash-free, cost effective to construct, and can easily be adapted to specific requirements. These systems are therefore recommended for regular use. The suitability of the two mayfly species for routine toxicity testing was evaluated. A. auriculata EC50 values showed a significant negative correlation with the corresponding average body-size (range 1476 - 1610 μm, mean 1555 μm). The different average body-sizes probably reflected the abundance of a certain size range present in the Palmiet River at the time of collection. Both species reacted similarly to Na₂S0₄ (similar slopes of the toxicity curves), identifying this salt as a slow acting toxicant. A. sudafricanum populations were more sensitive to Na₂S0₄ (EC50 3.404 g/L) than A. auriculata (EC50 8.090 g/L), probably because of its smaller body-size (mean 709 μm) and a lack of extremely tolerant individuals. In comparison to other freshwater macro invertebrates, including the standard toxicity test organism Daphnia spp., both mayfly species seemed to be moderately tolerant of Na₂S0₄; therefore there was no particular advantage to using these indigenous taxa rather than Daphnia spp. An assessment of the effects of elevated salinity/TDS levels on the test taxa yielded preliminary insights. A NaCI-EC50 for A. sudafricanum could be extrapolated and suggested a higher sensitivity to Na₂S0₄ than to NaCl. When Na₂S0₄ EC50 values of both species were compared to selected TDS levels of South African rivers, 4. auriculata would mostly not be affected, but A. sudafricanum might occasionally suffer from sub-lethal effects, depending on the sulphate proportion of the TDS. The South African guideline for TDS seemed to protect both species sufficiently.
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  • Date Issued: 2000

An evaluation of the life science curriculum in Namibia and its development through stakeholders' perceptions of ʺlearner centred educationʺ

  • Authors: Kristensen, Jesper Olsson
  • Date: 2000
  • Subjects: Life science project Curriculum evaluation -- Namibia Environmental education Educational change -- Namibia Life sciences -- Study and teaching -- Evaluation
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1527 , http://hdl.handle.net/10962/d1003409
  • Description: Following Independence in 1991 Namibia embarked on a major reform of the entire education system. The reform was perceived as a way of redressing the apartheid legacy and bringing about a democratic learner centred education for all. At the same time the reform was also seen as a prime vehicle to bring about sustainable development through incorporating relevant environmental education into various carrier subjects. One such carrier has been the subject Life Science, which is compulsory from Grade 8 to Grade 10. The Life Science Project was a joint venture between the Ministry of Education and Ibis, a Danish Development NGO, established to develop and support the implementation of Life Science in junior secondary schools. This half-thesis is an evaluation of the Life Science Project through an analysis of the central assumptions on which the Life Science curriculum is based and by investigating different stakeholders’ perceptions and understanding of the learner centred approach adopted by the curriculum. Three questions have guided this research: 1. Are there curriculum models that are more conducive for reform and change than others? 2. Do stakeholders and curriculum developers in Namibia understand the theory of social constructivism, and the systemic implications such an approach has for the education system? 3. Which approach to environmental education complements a transformative curriculum and the changes outlined in policy? From the research carried out in this half-thesis, it would appear that the Namibian education system and the Life Science curriculum suffers from what could be termed “ideological confusion”. Confusion in the sense that there are marked inconsistencies between policy and praxis, between the stated goals and aims of the reform and the curriculum designed to achieve these. This confusion is further exacerbated by various stakeholders’ different interpretations of both policy and the systemic implications the reform policy has on education. In this half-thesis I argue that embarking on an objectives driven model of curriculum cannot bring about change and transformation of the Namibian education system. I further argue that, by not having considered and implemented the necessary systemic changes to the education system, Namibia has, in fact, developed a child centred education system which is fundamentally different from a learner centred education system. Finally, I argue that environmental education, through the subject Life Science, set within an objectives driven, Child Centred Education system is inappropriate for and unable to address the need for developing an environmentally literate citizenry who are able to take informed decisions in order to address the environmental crisis and bring forth a more sustainable future.
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  • Date Issued: 2000

An examination of the drafting-responding process used to develop students' writing in an English Language for Academic Purposes Course

  • Authors: Quinn, Lynn
  • Date: 2000
  • Subjects: English language -- Study and teaching (Higher) -- Foreign speakers , Rhodes University -- Academic Development Programme , Academic writing -- Study and teaching (Higher) -- South Africa , Educational anthropology -- South Africa , Educational sociology -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2359 , http://hdl.handle.net/10962/d1002642 , English language -- Study and teaching (Higher) -- Foreign speakers , Rhodes University -- Academic Development Programme , Academic writing -- Study and teaching (Higher) -- South Africa , Educational anthropology -- South Africa , Educational sociology -- South Africa
  • Description: Many students when they arrive at university do not possess the “cultural capital” (Bourdieu 1977) which is favoured by the institution. The purpose of the English Language for Academic Purposes (ELAP) course and the drafting-responding process is to help students to begin to acquire the “cultural capital” required to succeed at university. The research reported on in this thesis examined the drafting-responding process as it is used to develop students’ writing in the ELAP course at Rhodes University. The process involved students submitting drafts of their essays on which they received constructive and formative feedback from their ELAP tutor. This feedback was then used to revise their essays before a final version was submitted for assessment. The research took the form of a case study with an essentially interpretive orientation. I examined the drafts (with the tutor’s comments) and final versions of seven students’ ELAP essays. Additional data was obtained by interviewing the students and the tutor. Underpinning my beliefs regarding the role of writing in learning as well as my orientation to research is an understanding of knowledge and learning as being socially constructed. All writing is embedded in and dependent on, not only the immediate social circumstances, but also the broader social and cultural context. In analysing and discussing the data in this research I used Halliday’s (1985) definition of context, in which he draws a broad distinction between the immediate context of situation and the broader context of culture The research findings showed that the drafting-responding process can help students with the process of developing the academic literacy they need in order to write essays within specific situational contexts, in this case, the context of the ELAP course. In addition, at a broader level, it can help students to begin the process of being initiated into the culture of the university as a whole.
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  • Date Issued: 2000

An examination of the facilitatory role for environmental education of conservancies

  • Authors: Law-Jackson, Danielle
  • Date: 2000
  • Subjects: Environmental education Nature conservation -- South Africa Wildlife conservation -- South Africa Conservation of natural resources -- South Africa
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1529 , http://hdl.handle.net/10962/d1003411
  • Description: This study examines the possibilities within the conservancy movement for the facilitation of environmental education. By means of a case study approach, a conservancy in the Northern Cape and the conservancy movement within the Free State provinces are compared with a view to elucidating factors militating against and promoting the success of environmental education programmes. The current lack of research in isolated rural areas is discussed. Re-orientation of perspectives regarding the value of conservancy-based environmental education within governmental, academic and local circles is recommended.
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  • Date Issued: 2000

An exploration of female physicality and psyche and how these inform art-making

  • Authors: Poole, Tanya Katherine
  • Date: 2000
  • Subjects: Women artists , Women artists -- Psychology , Rego, Paula -- Interviews , Feminism , Women -- Sexual behavior , Sherman, Cindy , Saville, Jenny, 1970-
  • Language: English
  • Type: Thesis , Masters , MFA
  • Identifier: vital:2419 , http://hdl.handle.net/10962/d1002215 , Women artists , Women artists -- Psychology , Rego, Paula -- Interviews , Feminism , Women -- Sexual behavior , Sherman, Cindy , Saville, Jenny, 1970-
  • Description: This thesis proposes that female physicality informs the psyche and thus in turn, art-making. My argument will be shown to be apposite and informative to the discussion of the work of Paula Rego, Jenny Saville and Cindy Sherman. Furthermore such an understanding is helpful to a reading of my practice. In examining issues of identity, which contribute to the formulation of a distinctly female psyche, I will base my critique on the philosophical positions of Sartre, de Beauvoir and Paglia.
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  • Date Issued: 2000

An exploration of the interaction between integration and discipline in a former model C school in East London

  • Authors: Smulders, Heidi
  • Date: 2000
  • Subjects: School discipline -- South Africa -- Eastern Cape -- Case studies , Multicultural education -- South Africa -- Case studies
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3061 , http://hdl.handle.net/10962/d1002570 , School discipline -- South Africa -- Eastern Cape -- Case studies , Multicultural education -- South Africa -- Case studies
  • Description: Educators work in dynamic contexts which reflect the social and political circumstances of the time. Since the African National Congress was elected to govern in 1994, educators working in former Model C schools have been particularly affected by changes in the law regarding education. The South African Schools Act of 1996 prohibited discriminating in any way against learners applying for admission to schools. This has resulted in cultural and racial integration occurring at all former Model C schools. The use of corporal punishment in schools was also prohibited in 1996. This study attempts to obtain an understanding of the interaction between integration and discipline which was identified at a particular Model C school in East London. It also aims to obtain educators' understandings of the challenges of integration and discipline at this school. Following an in-depth pilot study of the school's detention records for 1998, twenty-two out of sixty educators at the school participated in the research by responding to written questionnaires. It is argued that two different approaches to integration are presently used by educators. These are identified and discussed, namely assimilatory education and multicultural education. The need for consistency between educators in their approaches to integration and discipline is also addressed.
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  • Date Issued: 2000

An informed community's perception of the impact of digital technology on the credibility of news photography

  • Authors: Làzaro, Angelique Maria
  • Date: 2000
  • Subjects: Photojournalism -- Moral and ethical aspects , Digital media , Photojournalists , Photography -- Digital techniques
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3451 , http://hdl.handle.net/10962/d1002905 , Photojournalism -- Moral and ethical aspects , Digital media , Photojournalists , Photography -- Digital techniques
  • Description: South African photojournalists’ perception of digital technology’s impact on the credibility of news photographs is investigated in this study. Digital technology has the capabilities to produce “manipulated” photographs that appear realistic and credible. Credibility is dependent on a variety of factors including codes of realism and codes of production, which fit conventional codes of photographic representation. Manipulation is the act of deviating from accepted codes of photographic representation that may jeopardise the credibility of news photography. This thesis proposes a new theoretical framework that encompasses existing theories of semiotics, ideology, naturalism, realism and credibility. These theories underpin the definitions and discussion on manipulation and credibility. A descriptive survey is used which attempts to discover photojournalists’ views towards credibility. This research draws on qualitative research methods using a largely qualitative questionnaire, which generates both qualitative and quantitative data. The questions are formulated around two case studies of digitally manipulated photographs. The trends and responses in the research data are connected and discussed. The findings of this study are discussed in terms of credibility, awareness of the digital changes, the reason for the changes, the role of a caption, deletion techniques and background changes. The empirical situation is analysed in relation to the theoretical discussions and this study’s theorisation of photographic representation.
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  • Date Issued: 2000
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