Showing items 81 - 100 of 333

Your selections:

Creating a Web-based Spatiotemporal GIS using Java and VRML

  • Authors: Clayton, Peter G , Wells, George C , Preston, Michael
  • Date: 1999
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/433413 , vital:72968 , https://www.learntechlib.org/p/7417/
  • Description: This paper presents our approach towards creating a Web-based Spatiotemporal Geographic Information System, in particular, the creation of the spatial data set and the component interaction. It explores the possibility of rendering Virtual GIS Worlds in near real time across the WWW using a standard Web browser as the user interface. A" proof of concept" Web-based VGIS application was developed to investigate methods for the efficient transfer of high-bandwidth multimedia GIS content over the WWW, as well as providing a suitable development environment for research into Web-based Temporal GIS. This paper describes how VRML and Java were used to provide the visualisation of virtual worlds, interaction with individual objects inside the virtual world, and the query tools for adding, deleting, selecting or manipulating these objects or their associated attribute data.
  • Full Text:
  • Date Issued: 1999

Cumulative mild head injury in rugby: cognitive test profiles of professional rugby and cricket players

  • Authors: Ancer, Ruth Lauren
  • Date: 1999
  • Subjects: Head -- Wounds and injuries , Rugby football injuries , Cricket injuries , Cognitive therapy , Neuropsychological tests
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2925 , http://hdl.handle.net/10962/d1002434 , Head -- Wounds and injuries , Rugby football injuries , Cricket injuries , Cognitive therapy , Neuropsychological tests
  • Description: This study investigates the effects of cumulative concussive and subconcussive mild head injury on the cognitive functioning of professional rugby players. A comprehensive battery of neuropsychological tests was administered to 26 professional rugby players and a noncontact sport control group of 21 professional cricket players. The test performances of the rugby players were compared to those of the cricket players. Within the rugby group, forward and backline players were compared. An analysis of mean score differences between the rugby and cricket group failed to support the presence of brain damage effects in the rugby group. However, there was significantly increased variability of scores for the rugby players compared with the cricket players on tests particularly sensitive to cognitive deficit associated with mild head injury. This invalidates the null indications of average effects, indicating that a notable proportion of rugby players’ performances were falling off relative to the rest of the rugby players on tests vulnerable to the cognitive effects of diffuse brain damage. Mean score comparisons within the rugby group indicated that it was the subgroup of forward players, in particular, whose test performances revealed deficits suggestive of cerebral damage. Specifically, deficits were found in working memory, visuoperceptual tracking, verbal memory and visual memory, a pattern of deficits commensurate with cumulative mild head injury. The theoretical perspectives of Satz’s (1997) Brain Reserve Capacity Theory and Jordan’s (1997) ‘Shuttle’ model of variability are drawn upon in order to elucidate research findings and suggestions for future research are provided.
  • Full Text:
  • Date Issued: 1999

D'jinke Mousso

  • Authors: Batoma Sissoko (lead singer) , Batoma Sissoko
  • Date: 1999
  • Subjects: Popular music , Popular music--Africa, West , Africa Mali Bamako f-ml
  • Language: Malinka
  • Type: sound recordings , field recordings , sound recording-musical
  • Identifier: http://hdl.handle.net/10962/131154 , vital:36529 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC50-01
  • Description: Mandingo popular song with lead female vocal, accompanied by chorus, n'goni, balafon, Malian percussion, and other traditional Malian instruments, combined with Western guitar and drums
  • Full Text: false
  • Date Issued: 1999

Dankorobo

Declaration on HIV/AIDS

  • Authors: COSATU, SAMWU
  • Date: 1999
  • Subjects: COSATU, SAMWU
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/162072 , vital:40754
  • Description: This Special Congress of COSATU notes the relentless advance of HIV and AIDS since the 1997 Congress. 3,5 million people in South are infected with the Human Immuno-deficiency Virus (HIV). Life expectant South Africa will reduce to 40-45 over the next ten years and health care costs will be beyond the cape of survivors to pay for. It is now clear that publicity and condom distribution, though important, are enough. This requires a new approach and strategy, based on a partnership between government and society in which the organised working class should play a leading role.
  • Full Text:
  • Date Issued: 1999

Devaluation

  • Authors: Batoma Sissoko (lead singer) , Batoma Sissoko
  • Date: 1999
  • Subjects: Popular music , Popular music--Africa, West , Africa Mali Bamako f-ml
  • Language: Malinka
  • Type: sound recordings , field recordings , sound recording-musical
  • Identifier: http://hdl.handle.net/10962/131205 , vital:36536 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC50-06
  • Description: Mandingo popular song with lead female vocal, accompanied by chorus, n'goni, balafon, Malian percussion, and other traditional Malian instruments, combined with Western guitar and drums
  • Full Text: false
  • Date Issued: 1999

Development and characterisation of a membrane gradostat bioreactor for the bioremediation of aromatic pollutants using white rot fungi

  • Authors: Leukes, Winston D
  • Date: 1999
  • Subjects: Aromatic compounds Pollutants Fungi Bioremediation Industrial microbiology Biotechnology
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4032 , http://hdl.handle.net/10962/d1004092
  • Description: Bioremediation of aromatic pollutants using the ligninolytic enzymes of the white rot fungi has been thoroughly researched and has been shown to have considerable potential for industrial application. However, little success in scale-up and industrialisation of this technology has been attained due to problems associated with the continuous production of the pollutant-degrading enzymes using conventional bioreactor systems. The low productivities reported result from the incompatibility of conventional submerged culture reactor techniques with the physiological requirements of these fungi which have evolved on a solid-air interface, viz. wood. The enzymes are also produced only during the stationary phase of growth and can therefore be regarded as secondary metabolites. This study reports the conceptualisation, characterisation and evaluation of a novel bioreactor system as a solution to the continuous production of idiophasic pollutant degrading enzymes by the white rot fungus Phanerochaete chlysosporium. The reactor concept evolved from observation of these fungi in their native state, i. e. the metabolism of lignocellulosic material and involves the immobilisation of the organism onto a capillary ultrafiltration membrane. Nutrient gradients established across the biofilm, an inherent characteristic of fixed bed perfusion reactors, are exploited to provide both nutrient rich and nutrient poor zones across the biofilm. This allows growth or primary metabolism in the nutrient rich zone, pushing older biomass into the nutrient poor zone where secondary metabolism is induced by nutrient starvation. In effect, this represents a transformation of the events of a batch culture from a temporal to a spatial domain, allowing continuous production of secondary metabolites over time. Direct contact of the outer part of the biofilm with an air stream simulated the solid-air interface of the native state of the fungus. In order to facilitate the practical application of the membrane gradostat reactor (MGR) concept, conventional capillary membranes and membrane bioreactor modules were first evaluated. These were found to be unsuitable for application of the MGR concept. However, critical analysis of the shortcomings of the conventional systems resulted in the formulation of a set of design criteria for the development of a suitable membrane and module. These design criteria were satisfied by the development of a novel capillary membrane for membrane bioreactors, as well as a transverse flow membrane module, which is a novel approach in membrane bioreactor configuration. For the physiological characterisation of the MGR concept, a single fibre bioreactor unit was designed, which allowed destructive sampling of the biofilm for analysis. Using this system, it was shown that distinct morphological zones could be observed radially across the mature biofilm obtained through MGR operation. That these morphotypes do represent the temporal events of a typical batch culture in a spatial domain was confirmed by following the morphological changes occurring during batch culture of the immobilised fungus where the onset of primary and secondary metabolic conditions were manipulated through control of the nutrient supply. The different morphotypes were correlated to distinct growth phases by comparison of the morphology to the secretion of known enzymatic markers for secondary metabolism, viz. succinate dehydrogenase and cytochrome C oxidoreductase. Detailed structure-function analysis of the biofilm using transmission electron microscopy and adapted enzyme cytochemical staining techniques showed that the biofilm appeared to operate as a co-ordinated unit, with primary and secondary metabolism apparently linked in one thallus through nutrient translocation. This study provided new insights into the physiology of P. chrysosp,o rium and a detailed descriptive model was formulated which correlates well to existing models of wood degradation by the white rot fungi (WRF). Evaluation of the process on a laboratory scale using a novel transverse flow membrane bioreactor showed that a volumetric productivity of 1916 U.L.⁻¹day⁻¹ for manganese peroxidase, one of the pollutant degrading enzymes, could be attained, corresponding to a final concentration of 2 361 U.L.⁻¹ This may be compared to the best reported system (Moreira el at. 1997), where a volumetric productivity of 202 U.L.⁻¹day⁻¹was achieved with a final concentration of 250 U.L.⁻¹ However, MGR productivity is yet to be subjected to rigorous optimisation studies. The process could be operated continuously for 60 days. However, peak productivity could not be maintained for long periods. This was found to be due to physical phenomena relating to the fluid dynamics of the system which caused fluid flow maldistribution, which would have to be resolved through engineering analysis. In evaluation of the MGR concept for aromatic pollutant removal, in this case ρ- cresol, from growth medium, good performance was also achieved. The VmaxKm calculated by linear regression for the MGR was 0.8 (R² = 0.93), which compared favourably to that reported by Lewandowski et al. (1990), who obtained a Vmax/Km of 0.34 for a packed bed reactor treating chlorophenol. It was concluded that the MGR showed suitable potential to warrant further development, and that the descriptive characterisation of the biofilm physiology provided a sufficient basis for process analysis once engineering aspects ofthe system could be resolved.
  • Full Text:
  • Date Issued: 1999

Development of a model of performance indicators required for the effective management of South African Universities and Technikons

  • Authors: Hutton, Wendy
  • Date: 1999
  • Subjects: Universities and colleges -- South Africa -- Management , Performance -- Management , Performance standards , Performance -- Measurement
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:10826 , http://hdl.handle.net/10948/16 , Universities and colleges -- South Africa -- Management , Performance -- Management , Performance standards , Performance -- Measurement
  • Description: Research has been conducted on performance indicators in higher education institutions in a number of countries. However, in South Africa limited research in this field on a national level is available to the management of South African higher education institutions. The change in funding of these institutions has led to performance measurement becoming essential in order to justify the use of public funds. In order to obtain more relevant information about performance indicators in the South African context, a literature study was conducted to develop a questionnaire to test the concurrence of the importance of performance indicators in South African universities and technikons. The findings of the survey shows a high level of concurrence for the performance indicators identified in the literature study.
  • Full Text:
  • Date Issued: 1999

Development of integrated biological processing for the biodesalination of sulphate- and metal-rich wastewaters

  • Authors: Boshoff, Genevieve Ann
  • Date: 1999
  • Subjects: Sewage -- Purification -- Biological treatment Sulfates Mineral industries -- Environmental aspects
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:3899 , http://hdl.handle.net/10962/d1003958
  • Description: The substantial pollution threat to the South African environment from acid mine drainage (AMD) effluents has been well documented. Due to the juvenile nature of acidity in these flows, any remediation strategies implemented will need to function effectively and at low cost for long periods of time. The widespread use of sulphate reducing biological systems for the treatment of such effluents, and in particular large volume flows, has been limited. The supply of inexpensive electron donor and carbon sources, as well as appropriate reactor designs capable of handling large volume flows, have been identified as among the principal factors limiting development of this technology. The broad aim of the research programme reported here was to undertake an evaluation of the feasibility of an algal-bacterial integrated ponding system for the treatment of AMD, and the waste stabilisation pond (WSP) as an appropriate reactor design for this application. The study attempted to demonstrate the feasibility of individual unit operations in a proposed process train using complex organic carbon serving as the electron donor source for the sulphate reducing bacteria (SRB). Studies were undertaken as laboratory and pilot-scale investigations. Tannery effluent was shown to be a functional carbon source for biological sulphate reduction, with effective removal of sulphate and organics being recorded. In turn, the use of biological sulphate reduction for the treatment of tannery effluent was demonstrated. Algal biomass was shown in laboratory studies to function as an effective carbon source for biological sulphate reduction. It is known that micro-algae produce large quantities of photosynthate which is released to the growth medium under conditions of physiological stress. The potential for the use of photosynthate production in high rate algal ponding systems and its manipulation and use as a sustainable carbon source for sulphate reduction was investigated. Growth of a mixed culture of Dunaliella under conditions of light, temperature and salinity stress demonstrated production of large quantities of organic carbon. However, growth was inhibited at high temperatures. An elevation of salinity levels led to a decrease in growth of Dunaliella, but to increased organic carbon production. Spirulina spp., on the other hand, grew well at higher temperatures but showed the highest organic carbon production, and release to the medium, under low light conditions. These results led to a proposed process for the integration of algal ponding into an integrated system for the treatment of AMD. The algal biomass may be fed into the anaerobic digester as a carbon source, or it may be passed into a High Rate Algal Pond (HRAP) where it is stressed to enhance the organic carbon content. This can then be fed into the anaerobic digester as a carbon source. The impact of high levels of sulphide in the water feeding to the algal growth compartment was investigated. Spirulina spp. isolated from a tannery waste stabilisation pond was shown to be a sulphidophilic strain of cyanobacterium, capable of being adapted to high concentrations of sulphide. Dunaliella salina on the other hand was less tolerant. These results demonstrated the practical use of algal biomass providing an oxygen-rich cap for odour control on the surface of the facultative pond as well for the secondary treatment of sulphide-rich overflow to the High Rate Algal Pond. The ability of micro-algae to elevate the pH of their surrounding environment was evaluated as a functional precipitant and neutralisation reagent for acidic metal containing wastewater. Spirulina spp. was shown to perform effectively. D. salina was less functional in this environment. Anacystis spp. was effective in elevating the pH of a defined medium as well as a zinc-rich effluent. These results indicated the practicality of a neutralising function for algal ponds in the treatment of AMD. Metal removal in the system was found to be a combined function of sulphide precipitation, removal by binding to micro-algal biomass and extracellular polymeric substances. The feasibility of waste stabilisation ponding technology use for the treatment of large volume AMD effluents was provisionally demonstrated. It was shown that complex carbon sources would be used as efficient electron donors for sulphate reduction. The integration of algal ponding into the system provides for the generation of a sustainable carbon source, odour control with the recycling of oxygen-rich water onto the top of the facultative pond, secondary treatment of the anaerobic digester overflow, and the neutralisation of the incoming acidic effluents and removal of heavy metals. Integration of the individual unit operations, the feasibility of which has been provisionally demonstrated in this study, into a continuous process train is being investigated in follow-upstudies.
  • Full Text:
  • Date Issued: 1999

Dianguina

Diarabi

Didadi

Diggale

Dioko

Diongama

Diour Sanni

Djanfa

Djesse

Djinke Mousso

  • Authors: Batoma Sissoko (lead singer) , Batoma Sissoko
  • Date: 1999
  • Subjects: Popular music , Popular music--Africa, West , Africa Mali Bamako f-ml
  • Language: Malinka
  • Type: sound recordings , field recordings , sound recording-musical
  • Identifier: http://hdl.handle.net/10962/131240 , vital:36542 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC50-09
  • Description: Mandingo popular song with lead female vocal, accompanied by chorus, n'goni, balafon, Malian percussion, and other traditional Malian instruments, combined with Western guitar and drums
  • Full Text: false
  • Date Issued: 1999

Djongoma

  • Disclaimer
  • Privacy
  • Copyright
  • Contact