Family diversity : a South African perspective focusing on Whites in Grahamstown
- Authors: Ziehl, Susan C
- Date: 1998
- Subjects: Families -- History -- Research Families -- South Africa -- Grahamstown Families Families -- Research -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3341 , http://hdl.handle.net/10962/d1004467
- Description: Drawing on developments in the field of family history and studies of families in contemporary settings, the study addresses the question of explaining variations in household patterns. Its empirical basis is a survey of White households in Grahamstown. The surveyed population was broken down in terms of class (occupation) and culture (language) and analyses conducted to determine if there are any statistically significant relationships between these variables and the tendency to reside in particular household structures. The question of 'family ideology' was also addressed as an attempt was made to uncover subjects' views on a variety of family-related issues. On the basis of the research results, a model of the relationship between class, culture and household structure was developed. Its application to a comparison of Black and White household structures in South Africa as well as the United States, is discussed. Finally, attempts at redefining the family are addressed and a new definition of the family proposed.
- Full Text:
- Date Issued: 1998
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.
- Full Text:
- Date Issued: 1998
Nifedipine-cyclodextrin binary systems : solid-state photostability and dissolution behaviour
- Authors: Worthington, Matthew Stanley
- Date: 1998
- Subjects: Nifedipine Calcium -- Antagonists Cyclodextrins Cyclodextrins in pharmaceutical technology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3830 , http://hdl.handle.net/10962/d1007233
- Description: Nifedipine is a photolabile calcium channel antagonist which undergoes rapid photodegradation in solution and in solid-state with an accompanying loss of pharmacological potency and clinical efficacy. Nifedipine photostabilization which has received considerable attention has principally been achieved by physical obscuration and through the use of colourants or ultraviolet light absorbers incorporated into liquid preparations, translucent packaging materials, gelatin capsules and/or their fillings and tablet coatings or cores. This study was initiated by a South African pharmaceutical manufacturer in response to increasing evidence that cyclodextrin (CD) inclusion complexation may improve drug photostability. The brief was to evaluate the potential of selected cyclodextrins as photoprotecting agents for nifedipine in the solid-state. Areas of investigation included i) quantitative method development and validation for selective determination of nifedipine, ii) phase solubility studies to establish the solubilizing potential and complexing tendencies of selected cyclodextrins, iii) preparation of solid-state nifedipine - cyclodextrin binary systems using an industrially applicable method, iv) pre-formulation photostability studies to determine the effects of the cyclodextrins on solid-state nifedipine photostability and v) comparative in vitro dissolution assessments of nifedipine, the nifedipine - cyclodextrin binary systems and their respective physical mixtures. Phase solubility studies demonstrated that soluble nifedipine - cyclodextrin complexes were formed in aqueous solution, but the magnitude of the interactions were generally low as reflected by the calculated stability constants which decreased in the rank order, heptakis (2,6-dimethyI)-β-CD (DM-β-CD) > randomly methylated-β-CD (RM-β-CD) > β-CD ≈ 2-hydroxypropyl-β-CD (2HP-β- CD) > γ-CD ≥ 2-hydroxypropyl-γ-CD (2HP-γ-CD). An industrially applicable kneading method yielded binary systems with spectral and thermal characteristics similar to the respective physical mixtures, implying weak solid-state inclusion complexation. Preparation of an amorphous nifedipine - RM-β-CD product using a heating method is reported. A 1.7- and 1.9-fold improvement in solid-state nifedipine photostability was observed for I : 1 molar ratio β-CD and γ-CD kneaded products, respectively, when exposed to window-filtered daylight and could be attributed to changes in opacity of the crystalline kneaded products. The remaining cyclodextrins produced negligible nifedipine photostabilization. Nifedipine in vitro dissolution was improved considerably from γ-CD and RM-β-CD .kneaded products as a result of increased nifedipine wettability, solubility and reduced particle size. iii
- Full Text:
- Date Issued: 1998
A profile of young sex offenders in South Africa : a pilot study
- Authors: Wood, Catherine Jane
- Date: 1998
- Subjects: Sex offenders -- Psychology , Paraphilias , Sex offenders -- South Africa -- Psychology , Teenage sex offenders -- South Africa -- Psychology , Teenage sex offenders
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3089 , http://hdl.handle.net/10962/d1002598 , Sex offenders -- Psychology , Paraphilias , Sex offenders -- South Africa -- Psychology , Teenage sex offenders -- South Africa -- Psychology , Teenage sex offenders
- Description: In-depth interviews and psychometric tests were conducted with 20 young, South African male, hands-on sex offenders, between the ages of seven and 15 years. These offenders were referred by both the legal system and the welfare and health system. The data was gathered for the purpose of drawing up a descriptive profile of salient psychological and sociological characteristics of this population group, the patterns of offenses, the circumstances under which the offenses occurred and victims selected. Results showed that half the sample had committed prior sex offenses. The majority of young sex offenders had a history of consenting sexual interactions, had committed a non-sexual offense and engaged in a range of other antisocial behaviours. Half the sample reported a history of physical or sexual abuse (under-reporting of such victimization experiences was suspected). Typically, the young sex offender w:~s sexually naive and had not received any suitable sex education. He was usually a scholar although his school attendance was often infrequent and he was likely to have failed one or more standards. His intelligence quotient was most likely to fall in or below the borderline range of functioning. He tended to be either socially isolated and socially anxious or alternatively reported having a number of friends and appeared to have adequate social skills. His home environment was typically characterized by overcrowding, alcohol abuse and domestic violence. A significant male relative of his was likely to have committed a criminal offense. In his community environment, he regularly witnessed violence and sexual activity. The sex offenses were usually carried out with a co-perpetrator in a variety of venues. The victim was usually known and younger (mean age = seven years) than the perpetrator (mean age = 12 years). The overall results suggest that young sex offenders commit an array of sexual offenses that do not represent sexual experimentation, but rather indicate a developing pattern of sexual deviance. Comparisons between the above profile and the literature findings are explored. Finally, recommendations for structural changes, assessment procedures, additional future research pessibilities and guidelines for the development of appropriate - treatment programmes are outlined.
- Full Text:
- Date Issued: 1998
Graphicacy as a form of communication in the primary school
- Authors: Wilmot, Pamela Dianne
- Date: 1998
- Subjects: School children -- South Africa Visual communication Perception in children Visual literacy Pictures
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1551 , http://hdl.handle.net/10962/d1003433
- Description: Children of today inhabit a multi-dimensional world, and in order to communicate effectively in it, they need the ability to utilise four forms of communication namely, oracy, literacy, numeracy and graphicacy. Communicating in graphic form requires an ability to both encode and decode spatial information using symbols, which requires the utilisation and application of spatial perceptual skills and concepts. The acquisition of graphic skills has been influenced by traditional developmental perspectives; increasingly the assumptions underpinning these have been challenged by more recent international research findings. The draft Curriculum Framework for General and Further Education and Training (1996: 18) identifies graphic literacy as one of the critical outcomes of the new South African curriculum. For graphic literacy to be an achievable outcome of the new curriculum, we need to investigate the skills and concepts underpinning this form of communication. The goal of this research is to investigate graphicacy as a form of communication in South African primary schools. However, given the scope of a research project of this nature, it was decided that rather than dealing with graphicacy per se, pictures as the most frequent and concrete type of graphic communication encountered by young learners would be focused on. In seeking to investigate pictures, the first stage of the study is concerned with diagnosing and illuminating children's graphic skill development through identifying: what skills they use; how they use and apply these when communicating through and interpreting symbols; and the difficulties they experience when, firstly, encoding spatial information through a series of practical and drawing tasks; and secondly, when reading and interpreting pictures. The second stage of the study investigates the extent to which children's early childhood experiences may or may not have impeded or enhanced the acquisition of skills necessary for understanding and communicating about space. The research findings, evaluated according to existing and emerging theoretical perspectives on graphicacy, will help to illuminate the current situation regarding the graphic literacy of South African primary school children. The study may contribute to wider international debates about graphicacy as a form of communication and the development of graphic literacy, from a South African perspective.
- Full Text:
- Date Issued: 1998
The removal and recovery of toxic and valuable metals from aqueous solutions by the yeast Saccharomyces cerevisiae
- Authors: Wilhelmi, Brendan Shane
- Date: 1998
- Subjects: Saccharomyces cerevisiae , Yeast fungi -- Biotechnology , Sewage -- Purification -- Heavy metals removal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4002 , http://hdl.handle.net/10962/d1004062 , Saccharomyces cerevisiae , Yeast fungi -- Biotechnology , Sewage -- Purification -- Heavy metals removal
- Description: This project considered the use of the yeast Saccharomyces cerevisiae as a biosorbent for the removal and recovery of a range of metals from contaminated waters. S. cerevisiae, as a biosorbent, has the potential to provide a cost effective, selective and highly efficient purification system. Initial studies focused on metal accumulation by an immobilized baker's S. cerevisiae biosorbent. The parameters affecting metal uptake were investigated, these included metal concentration, time and solution pH. Metal uptake was rapid. Gold and cobalt reached saturation within 5 min of contact with the biosorbent in batch reactors. Copper, zinc, nickel, cadmium and chromium reached saturation within 30 min of contact. Metal accumulation was pH dependent and was generally unaffected at a solution pH ≥ 4, and was substantially decreased at pH ≤ 2. The exception was gold which was preferentially accumulated at a solution pH of 2. The immobilized baker's yeast accumulated metals with maximum binding capacities in the order of gold > cadmium > cobalt > zinc > copper > chromium > nickel. A rapid method to assess metal recovery was developed. Bioaccumulated metal was efficiently recovered using dilute mineral acids. Copper recovery of ≥ 80 % was achieved by decreasing the solution pH of the reaction mixture to 2 with the addition of nominal quantities of HCl, H₂SO₄ or RNO₃. Adsorption-desorption over 8 cycles had no apparent adverse effect on metal uptake or recovery in batch reactors. Transmission electron microscopy showed no evidence of damage to cells used in copper adsorption-desorption investigations. Biosorption columns were investigated as bioreactors due to their application potential. The metals investigated were effectively removed from solution. At a saturation threshold, metal uptake declined rapidly. Most metals investigated were desorbed from the columns by eluting with 0.1 M HCl. Initially recoveries of copper, cobalt and cadmium were as high as 100%. Desorbed copper, zinc, cadmium, nickel and cobalt were concentrated in 10 to 15 ml of eluent, representing up to a 40 fold decrease in solution volume. Cadmium, nickel and zinc uptake increased with the second application to the columns. Initial accumulation of gold and chromium was 42.2 μmol/g and 28.6 μmol/g, however, due to the low recoveries of these two metals, a second application was not investigated. Copper was applied to a single column for 8 consecutive adsorption-desorption cycles. Uptake increased from an initial 31.3 μmol/g to 47.8 μmol/g at cycle 7. The potential for selective metal recovery was demonstrated using two biosorption columns in series. Copper was accumulated and recovered most efficiently. Zinc, cobalt and cadmium were displaced to the second column. Copper bound preferentially to zinc at a ratio of 6:1. Copper bound preferentially to cobalt at a ratio of 4:1. Cadmium was only displaced at a ratio of 2:1. The successful transfer of the bioremediation technology from the laboratory to an industrial application has yet to be realized. Bioremediation of a Plaatjiesvlei Black Mountain mine effluent, which contained copper, zinc, lead and iron, was investigated in this project. The removal of the metals was most effective at pH 4. A combined strategy of pH adjustment and bioremediation using immobilized S. cerevisiae decreased the copper concentration by 92.5%, lead was decreased by 90% and zinc was decreased by 60%. Iron was mostly precipitated from solution at pH ≥ 4. An ageing pond at the mine with conditions such as; pH, water volume and metal concentration, which were more conducive to biological treatment was subsequently identified. The investigation indicated a possible application of the biomass as a supplement to chemical remediation. The metal removal capability of a waste brewer's yeast was subsequently investigated. A yeast conditioning step increased metal uptake up to 100% and enhanced reproducibility. Metal removal from solution was rapid and pH dependent. The metals were efficiently removed from solution at pH ≥ 4. Uptake was substantially inhibited at pH ≤ 3. The waste brewer's yeast accumulated metals with maximum binding capacities in the order of copper (25.4 μmol/g) > lead (19.4 μmol/g) > iron (15.6 μmol/g) > zinc (12.5 μmol/g). No correlation between cell physiology and metal uptake was observed. Uptake of the four metals was confirmed by energy dispersive X-ray microanalysis. The interference of lead, zinc and iron on copper uptake by the waste brewer's yeast, and the interference of copper on the uptake of lead, zinc and iron was investigated. Maximum copper uptake was not decreased in the presence of lead. The Bmax remained constant at approximately 25 μmol/g. The dissociation constants increased with increasing lead concentrations. Lead bioaccumulation was significantly decreased in the presence of copper. The type of inhibition was dependent on the initial copper concentrations. Zinc had a slight synergistic effect on copper uptake. The copper Bmax increased from 30.8 μmol/g in a single-ion system to 34.5 μmol/g in the presence of 200 μmol/l of zinc. Zinc uptake was severely inhibited in the presence of copper. The maximum uptake and dissociation constant values were decreased in the presence of copper, which suggested an uncompetitive inhibition. The affinity of copper was substantially higher than zinc. The presence of higher levels of copper than zinc in the yeast cells was confirmed by energy dispersive microanalysis. Copper uptake was decreased in the presence of iron, with the copper Bmax being decreased from 25.4 μmol/g in a single-ion system to 20.1 μmol/g in the presence of 200 μmol/l iron. Iron Bmax values remained constant at 16.0 μmol/g. Combined biosorption and EDXA results suggested the iron bound at a higher affinity than copper to the cell wall. Total copper removal was higher as larger quantities of copper were deposited in the cell cytoplasm. Metal removal from the Plaatjiesvlei effluent by free cell suspensions of the waste brewer's yeast was satisfactory. Copper levels were decreased by 96%, iron by 42%, lead 25% and zinc 2%. Waste brewer's yeast is a cheap source of biomass in South Africa, and could potentially provide the basis for the development of an innovative purification system for metal-contaminated waters.
- Full Text:
- Date Issued: 1998
Countertransference in rape counselling
- Authors: Whyle, Susan Lynn
- Date: 1998
- Subjects: Countertransference (Psychology) -- Therapeutic use , Rape victims -- Counseling of
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3085 , http://hdl.handle.net/10962/d1002594 , Countertransference (Psychology) -- Therapeutic use , Rape victims -- Counseling of
- Description: The study examined rape counselling, with particular emphasis on countertransference reactions experienced by the counsellors of rape survivors. Four subjects participated in semi-focused, open-ended interviews, which were taped and transcribed verbatim. The phenomenon of countertransference was discussed, and countertransference reactions identified and examined. The management of empathic strain, in order to sustain empathic inquiry and therapeutic efficacy, was discussed. The main results of the study included the identification of common victim themes, and the feelings evoked in the counsellor in the therapeutic relationship. These included feelings of anger, hopelessness, helplessness and sadness, particularly in the counselling of children, who may be HIV positive as a result of the attack, and victims of chronic abuse. Challenges of rape counselling included shortcomings in the system, and rape myths which trivialize the crime and blame the victim. The need for education and enlightenment of both the public and magistrates on the deleterious effects of rape was emphasized by all subjects.
- Full Text:
- Date Issued: 1998
Ecological interactions on a rocky shore : the control of macroalgal distribution by intertidal grazers
- Authors: Whittington-Jones, Kevin John
- Date: 1998
- Subjects: Limpets -- South Africa , Mollusks -- Ecology , Mollusks -- Feeding and feeds , Mollusks -- South Africa , Cryptogams , Cryptogams -- South Africa , Algae -- Control , Algae -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5665 , http://hdl.handle.net/10962/d1005350 , Limpets -- South Africa , Mollusks -- Ecology , Mollusks -- Feeding and feeds , Mollusks -- South Africa , Cryptogams , Cryptogams -- South Africa , Algae -- Control , Algae -- South Africa
- Description: The aim of the present study was to determine the potential impact of intertidal grazers on the distribution of macro algae on the south coast of South Africa. Particular attention was paid to the large patellid limpet, Patella oculus, which is found thoughout the intertidal zone. Studies of gut contents revealed that Patella oculus was capable of ingesting not only the thallus of foliose (eg. Ulva spp.) and encrusting coralline macroalgae, but also spores and diatoms. The inclusion of these relatively small particles in the diet was surprising, as electron micrographs of the radula of P.oculus revealed that it is typically docoglossan in structure. Such radulae are thought to be poorly suited for collecting small food particles. Sand made up a significantly higher proportion of the gut contents than other particles at all shore heights, which suggests that P.oculus might be capable of excavating the rocky substratum, or of sweeping up sand, while searching for food. Analysis of the gut contents of other local herbivorous molluscs, was also carried out. These species included the winkles, Oxystele variegata and O.sinensis, and the small pulmonate limpets, Siphonaria concinna, S.capensis, and S.serrata. The guts of all species contained mainly spores and diatoms, although small fragments of Ulva sp. were found. The population structure of Patella oculus was investigated at two sites, Cannon Rocks and Old Woman's River. At Cannon Rocks, mean shell length of low-shore animals was significantly lower than that of both mid- and high-shore animals, while at Old Woman's River, no significant difference was found among shore heights. A regression equation for In (shell length) vs In (dry weight) was calculated, and based on length data, the biomass density (g dry mass.m⁻²) of P.oculus at Old Woman's River was estimated. Values ranged from 2.8 on the low- and midshore to 0.37 on the high-shore. A manipulative field experiment was used to determine the impact of mesograzers and macrograzers (such as Patella oculus) on the distribution of intertidal macro algae on the mid- and low-shore at Old Woman's River. Grazers were excluded using mesh cages (mesh size = 3mm), in two separate experiments, one in winter and the other in spring. Percentage cover of macroalgal species and sessile invertebrates was estimated at approximately 6 week intervals for up to 3 months. MANOV A showed that treatments did not significantly affect cover of macroalgae or barnacles during winter. However, towards the end of the spring experiment (midshore only) cover of barnacles and green foliose turfs did increase in those plots from which mesograzers and/or macro grazers were excluded. The failure of the statistical tests to detect significant differences at some time intervals may have been caused by high levels of variation among replicates. This suggests that factors other than grazing are of overriding importance in determining the distribution of local macroalgae. The existence of a possible symbiotic relationship between Patella oculus and the red foliose alga, Gelidium pristoides, was investigated. The availability of various substratum types, including rock, limpet shells, barnacles etc., and the proportion of the total cover of G.pristoides on each, was calculated. It was shown that a significantly higher proportion of the alga grew on limpet shells, although the availability of this substratum type was low. It is thought that the aggressive behaviour of P.oculus prevents all but juvenile Patella longicosta from grazing on its shell, thus providing a refuge from grazing for G.pristoides.
- Full Text:
- Date Issued: 1998
Eva's men : gender and power in the establishment of the Cape of Good Hope, 1652–74
- Authors: Wells, Julia C
- Date: 1998
- Language: English
- Type: Article
- Identifier: vital:6148 , http://hdl.handle.net/10962/d1006811 , http://dx.doi.org/10.1017/S0021853798007300
- Description: This article offers a fresh interpretation of the life of Krotoa/Eva, the famous Khoena interpreter of Jan Van Riebeeck, whose gender gave her a unique position in relation to both Dutch and Khoena society. It appears that her own people sent her to work for the Dutch as a young girl, both to serve as a token of goodwill, to gain prestige as the protegee of the household of a powerful leader and to become familiar with Dutch ways. The Dutch received her comfortably as a servant, child minder and companion for Van Riebeeck's young nieces. When Eva learned Dutch expertly, she quickly became their most trusted interpreter. The evidence also hints at an especially close and sensitive, possibly sexual, relationship between her and Van Riebeeck. When military conflicts left Eva identified as a Dutch collaborator, she contacted her sister's husband, chief Oedasoa. Her direct mediation enabled the Dutch to open up a profitable new trading enterprise with Oedasoa, who in turn used Eva as his personal agent within the Dutch community. Her unique position attracted the attention of a bright young employee of the Company, Pieter Van Meerhoff, who became her lover soon after his arrival at the Cape in 1659. Pieter became actively involved in northern expeditions of exploration and prided himself on his sensitivity and capacity to get on well with various Khoena chiefs. Eva continued as an interpreter, intermediary with Oedasoa and the couple had two children together. Eva and Pieter married only after Van Riebeeck left the Cape. Their decision to conform to the norms of Dutch society disappointed Oedasoa who had offered them enough livestock to establish an independent lifestyle but brought both much higher levels of respect from the Dutch, including significant promotions for Pieter. When Pieter was killed in 1666, heading up a trading mission to Mauritius, Eva's life sharply deteriorated. She died in 1674, accused of having become a drunken pest and prostitute. Eva's story exemplifies how an African woman in an early colonial encounter could manipulate a variety of gender roles. Seen as a safe intermediary by both Africans and Europeans, she built herself a unique career and formed a durable liaison with a spirited young man. However, as the nature of contact between the races deteriorated, her role as intermediary diminished in importance. Ultimately, without Pieter, she could not sustain her pivotal place in Dutch society, dying a miserable death. Her life reflects the rapidly changing nature of early colonial contacts.
- Full Text:
- Date Issued: 1998
In vitro release of amoxycillin from lipophilic suppositories
- Authors: Webster, Jessica A , Dowse, Roslind , Walker, Roderick B
- Date: 1998
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184377 , vital:44213 , xlink:href="https://doi.org/10.3109/03639049809085636"
- Description: The in vitro release characteristics of amoxycillin from different lipophilic suppository bases were investigated using the USP rotating basket method. Suppositories containing 250 mg amoxycillin were prepared in theobroma oil and in the semisynthetic bases Witepsol W35, Suppocire A32, Novata BD, and Novata 299. Both freshly prepared and 1-month-old suppositories were tested. Analysis of amoxycillin was performed using a validated high-performance liquid chromatographic (HPLC) technique. Release profiles differed significantly between bases, with the greatest amount of amoxycillin being released from both newly made and 1-month-old Novata BD bases (87.57 ± 8.18 and 99.66 ± 6.63%, respectively), and the lowest amount released from the newly manufactured theobroma suppositories (8.82 ± 0.75%) and the 1-month-old Suppocire A32 suppositories (7.78 ± 0.27%).
- Full Text:
- Date Issued: 1998
A framework for interpreting noisy, two-dimensional images, based on a fuzzification of programmed, attributed graph grammars
- Authors: Watkins, Gregory Shroll
- Date: 1998
- Subjects: Music -- Data processing Computer sound processing Artificial intelligence -- Musical applications Fuzzy systems
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4604 , http://hdl.handle.net/10962/d1004862
- Description: This thesis investigates a fuzzy syntactic approach to the interpretation of noisy two-dimensional images. This approach is based on a modification of the attributed graph grammar formalism to utilise fuzzy membership functions in the applicability predicates. As far as we are aware, this represents the first such modification of graph grammars. Furthermore, we develop a method for programming the resultant fuzzy attributed graph grammars through the use of non-deterministic control diagrams. To do this, we modify the standard programming mechanism to allow it to cope with the fuzzy certainty values associated with productions in our grammar. Our objective was to develop a flexible framework which can be used for the recognition of a wide variety of image classes, and which is adept at dealing with noise in these images. Programmed graph grammars are specifically chosen for the ease with which they allow one to specify a new two-dimensional image class. We implement a prototype system for Optical Music Recognition using our framework. This system allows us to test the capabilities of the framework for coping with noise in the context of handwritten music score recognition. Preliminary results from the prototype system show that the framework copes well with noisy images.
- Full Text:
- Date Issued: 1998
Genre analysis and the teaching of academic literacy: a case study of an academic discipline in the social sciences
- Authors: Vorwerk, Shane Paul
- Date: 1998
- Subjects: Lectures and lecturing , Lecture method in teaching , Language and culture , Discourse analysis , Language and culture -- South Africa , English language -- Discourse analysis , Intercultural communication -- South Africa , English language -- Study and teaching -- South Africa -- Foreign speakers
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2365 , http://hdl.handle.net/10962/d1002648 , Lectures and lecturing , Lecture method in teaching , Language and culture , Discourse analysis , Language and culture -- South Africa , English language -- Discourse analysis , Intercultural communication -- South Africa , English language -- Study and teaching -- South Africa -- Foreign speakers
- Description: Students in tertiary educational institutions in South Africa come from many different backgrounds and have varied educational experiences. Some students, especially those from non-English speaking backgrounds, may encounter linguistic difficulties with various academic tasks. In order for students to be successful at university, they must become academically literate. That is, they must master all the reading, writing, listening and comprehension tasks required by the disciplines in which they are studying. One such task is presented by the academic lecture which is an integral part of any course of study. Linguistically, the academic lecture can be seen as a particular genre with unique characteristics. This study investigated some linguistic characteristics of academic lectures. The discipline of Political Science, as a Social Science, was chosen because there is little research that has been done on language in the Social Sciences. The Political Science sub-disciplines of Political Philosophy, South African Politics, and International Relations were used in this research. First year lectures were recorded from each of these three sub-disciplines. The linguistic characteristics of lectures were analysed using techniques drawn from Systemic Functional linguistic theory. The analysis concentrated on the aspects mode and field as they were realised in the lectures. In addition, higher level generic structure was also analysed. The insights gained from the analysis were validated through interviews with the lecturers who gave the lectures. The aim of this research was to develop a linguistic characterisation of the lecture genre as it occurs in the three sub-disciplines of Political Science. The results of this research suggest that although there is a unified academic lecture genre, there is variation according to sub-discipline. The implications of this variation are discussed with reference to their relevance to teaching academic literacy.
- Full Text:
- Date Issued: 1998
Aspects of the biology of the doublesash butterflyfish, Chaetodon marleyi (Pisces: Chaetodontidae)
- Authors: Vine, Niall Gordon
- Date: 1998
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:21103 , http://hdl.handle.net/10962/6396
- Description: The doublesash butterflyfish, Chaetodon marleyi, indigenous to South Africa, is popular amongst marine aquarists. To provide a basis for the management of the species and assess its suitability for aquaculture, aspects of its biology were investigated. Specimens were collected between February 1996 and November 1997 from localities along the eastern Cape coastline of South Africa and from specimens in the RUSI fish collection. The dentition of C.marleyi is typical of non-coraline, benthic invertebrate feeding chaetodontids. The teeth are long, inwardly hooked and spatulate which allow easy grasping and manipulation of the prey. Stomach content analysis showed that the species fed predominantly on the tentacles of terebellid polychaetes with other polychaetes, crustaceans, hydro ids and ascideans contributing to the remainder of the diet. Juveniles had a larger volume of terebellid tentacles compared to adults which preyed more upon other polychaetes. The proximate composition (64.25% protein, 4.76% fat, 4.84% carbohydrate and 24.3 kJ/g total energy content) of the terebellid tentacles was determined suggesting a high energetic requirement of the fish or maximisation of feeding profit rates.
- Full Text:
- Date Issued: 1998
Interaction of nitric oxide with cobalt (II) phthalocyanine
- Authors: Vilakazi, Sibulelo L , Nyokong, Tebello
- Date: 1998
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293579 , vital:57100 , xlink:href="https://doi.org/10.1016/S0277-5387(98)00244-7"
- Description: The coordination of nitric oxide (NO) to cobalt(II) phthalocyanine (CoPc) in dimethyl sulphoxide (DMSO) has been studied. CoPc coordinates with NO in a 1:1 ratio, forming a CoPc(NO) species. The IR band observed at 1680 cm−1 is assigned to the coordinated NO. In the presence of excess NO, pseudo first order kinetics were followed. The observed rate constant, kf, was determined to be 15.0±0.3 dm−3 mol−1 s−1 and the equilibrium constant was K=5.4±0.4×104dm3 mol−1. Solution or adsorbed CoPc catalyses the reduction of NO. The products of reduction include NH3 and NH2OH.
- Full Text:
- Date Issued: 1998
Conservatism and change: the refashioning of gender relations from 1870 to 1914: a case study of East London
- Authors: Vernon, Gillian Noël
- Date: 1998
- Subjects: Women -- South Africa -- East London , Women -- South Africa -- Social conditions , Women's rights -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2567 , http://hdl.handle.net/10962/d1002420 , Women -- South Africa -- East London , Women -- South Africa -- Social conditions , Women's rights -- South Africa
- Description: This is a case study of East London from 1870 to 1914 with gender as the critical analytical category. The focus is on change in the structure of gender relations, evaluated in terms of the recognition of the rights of women and their status in society and women of all race groups are dealt with. A feature of the source material has been the use made of oral history where interviews were conducted with the descendants of women who lived during the study period. There were many indirect factors which had a retrogressive influence on progressive change in the rights and position of women. The initial small size of the population and unbalanced gender ratios, the few natural resources, a small and limited port and periodic unpredictable natural disasters gave rise to a 'boom and burst' economy with very little industry. The result was that initially the women were very conservative and unwilling to make social changes. The military occupation and the outbreak of hostilities in the late 1870s affected social and racial attitudes detrimentally. The entrenched patriarchal system, under which both black and white women lived, and the legal controls, particularly in the marital situation, reinforced the subordination of women, making the system difficult to break. Further conservative forces were at work with the European class system being well entrenched, with most women working for upward mobility, gentrification and respectability. Wealth was critical in determining status and those women from the working class, who had achieved some degree of wealth and status, were not prepared to challenge the system. Religion was important for nearly all white women and converted black women, but was a retarding influence in the growth of feminist consciousness. Little progress was made in improving the condition of women who transgressed the law, the non-respectable women, and ethnicity made no difference. Progress was made in gender relations for women in some fields. The reduction in family size and the improvement in health, gave women more time and energy for public affairs. Participation in sport helped women discard the image of being weak and frail and also improved health. Educational opportunities allowed some to get tertiary training and obtain proper qualifications to earn a living for themselves. Xhosa women who came into the town, made a major break with traditional society and many became independent. The major impetus for change came through women's associations, where women actively worked together and achieved some positive results. Middle class white women could earn an independent living without losing respectability, although it was accepted that women should give up paid employment on marriage. Black women broke traditional ties and many urban women became independent. Conditions for working class and non-respectable women changed very little. A deduction is that many women, both white and black, had sympathy for one another and they created a fund of goodwill on both sides of the colour line.
- Full Text:
- Date Issued: 1998
Group problem solving among community activists in a South African setting: an everyday cognition approach
- Authors: Van Vlaenderen, Hilde
- Date: 1998
- Subjects: Group problem solving Group problem solving -- South Africa Cross-cultural studies -- Methodology Cognition Cross-cultural studies Cognition -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3080 , http://hdl.handle.net/10962/d1002589
- Description: The study focuses on the everyday problem solving processes of a group of community activists in a rural setting in the Eastern Cape Province of South Africa. It aims to uncover: first, the local knowledge of the participants of the study with reference to the concepts problem and problem solving; second, the participants' group problem solving procedure; and third, the dialectical interrelation between the participants' knowledge and practice with reference to everyday group problem solving. It is contended that the mainstream cognitive approach and the cross-cultural tradition are inappropriate for the study of everyday cognitive processes. A ‘situated cognition’ approach, based on the notions of activity and cultural mediation, is proposed as a theoretical framework for the study. The ontological and epistemological assumptions underpinning the empirical study were derived from a scientific realist and a hermeneutical paradigm. Data for the inquiry into the local knowledge of the participants was collected through individual interviews. The data was interpreted, using the grounded theory techniques of constant comparison, coding and compiling theoretical diagrams. Data for the inquiry into the participants' group problem solving practice consisted of video-taped group problem solving processes. This data was analysed, using a multi layered process of progressively deeper interpretation, employing a reading guide technique. Analysis of the research data revealed that the participants perceived a problem as an impediment to satisfactory participation in society. Problem solving was considered as an emotive, cognitive and inter-active process, involving particular role players. This process had a certain structure, involved attitudes and actions and relied on particular resources. Successful problem solving was perceived to result in restoration of social equilibrium. The group problem solving procedure used by the participants consisted of a process of developing a common understanding and group consensus. The strategies employed in the process, the roles played by the participants, the rules adhered to by the participants and the structure underlying the process were all congruent with these aims. There was a mutually reinforcing interrelation between knowledge and practice with reference to the participants’ problem solving.
- Full Text:
- Date Issued: 1998
Improvement of fertility and hatchability of artificially incubated ostrich eggs in the little Karoo
- Authors: Van Schalkwyk, Salmon Jacobus
- Date: 1998
- Subjects: Ostrich farming -- South Africa , Eggs -- Hatchability , Eggs -- Incubation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5713 , http://hdl.handle.net/10962/d1005399
- Description: Ostriches are an important commercial species in South Africa and are becoming increasingly so in other parts of the world. Fertility and hatchability of artificially incubated ostrich eggs, however, is generally regarded as low compared to other poultry species and to ostriches in the wild. Investigation into specific farming practices at present indicated scope for an overall improvement in productivity through a sound breeding strategy. This thesis investigated factors that affect egg production, fertility, and hatchability of artificially incubated eggs in the Little Karoo region of South Africa. Specific breeding pair combinations accounted for the major variations in egg weight, hatchability, chick production and offspring weight at slaughter age. An appreciable proportion of variation in reproductive traits was attributable to the repeatable nature of breeding pair performance from year to year, even from first breeding attempts, suggesting that selection of good breeding stock can be made from an early age. Artificially incubated eggs showed improved hatchability when eggs were collected two to three hours after lay rather than the following morning. Storing position of eggs did not significantly effect hatchability when eggs were stored for a maximum of one week. The critical zero temperature for ostrich eggs, below which no embryonical development takes place, was found to be ± 25°C and cooling eggs to temperatures below 20°C for complete cessation of embryonic development during storage resulted in better hatchabilities compared to eggs stored at 25°C room temperature. Hatchability decreased when incubator temperatures were raised from 36 to 37.3°C. Large temperature fluctuations and gradients, which encompass detrimental temperatures, persist within forced draught wooden incubators of the type most commonly in use in the Little Karoo region. The highest temperatures occurred at the top of these incubators and will consequently have a negative impact on hatchability. The ontogeny of ostrich egg metabolism showed an exponential increase during the first 70% of incubation followed by a decline to 75% of the peak value between days 31 and 38 of incubation. From peak levels of embryonic development it was calculated that single stage incubators needs an airflow of 54.4 1/egg.hour to maintain oxygen levels just below 21% and carbon dioxide levels below 0.5%. Lower embryonic mortalities were observed when eggs were turned twenty-four times/day in an electronic incubator compared to hand turning twice a day. Eggs rotated through increasing angles between 60 and 90° resulted in a linear improvement in hatchability. In incubators where turning angles were fixed at 60°, lower hatchabilities were overcome by incubating eggs for 2 - 3 weeks in a horizontal position before placing them vertically. No specific farming practice could be singled out as the main cause of low fertility or hatchability but rather a combination of certain practices applied wrongly.
- Full Text:
- Date Issued: 1998
The invertebrates of temporary rivers in the Eastern Cape, South Africa
- Authors: Uys, Amanda Cloete
- Date: 1998
- Subjects: Rivers -- South Africa -- Eastern Cape Stream ecology -- South Africa -- Eastern Cape Freshwater invertebrates -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5628 , http://hdl.handle.net/10962/d1004908
- Description: Temporary rivers in dryland regions are subject to highly variable and unpredictable rainfall and flow, and are considered unstable systems relative to perennial rivers of temperate zones. Little is known of the ecology of South Africa's temporary rivers, despite their abundance. The research presented focusses on the aquatic invertebrates inhabiting intermittently-flowing rivers in the 'arid corridor' of the Eastern Cape, South Africa. The major aims of the work were: to investigate which invertebrates inhabit these rivers, how the fauna is affected by environmental variability at various spatial and temporal scales, whether or not a characteristic fauna can be associated with these rivers or the hydrological phases which characterise them, and to establish to what extent faunal overlap occurs between different temporary rivers and between natural and modified temporary and perennial rivers. Research results indicate that the fauna of the Eastern Cape temporary rivers shows little structure at the scales of investigation, and that communities are generally non-equilibrial in character. The major forces shaping the biota are considered to be physical rather than biological, and the most important of these are: present and antecedent hydrological conditions and their duration; time of year; and biotope character, extent and heterogeneity. Three groups of fauna were identified as inhabitants of the temporary rivers: 'residents', 'facultative taxa' and 'opportunist colonists'. Taxa were tentatively allocated to these groups. Faunal resemblance was fairly high in Eastern Cape temporary rivers at the level of family, but not at more detailed taxonomic levels. A comparison between faunas of temporary and perennial rivers in different regions of South Africa illustrated the influence of geographical location on diversity. Within regions, however, there was no indication that perennial rivers were more diverse than intermittent rivers. The relatively high diversities in temporary rivers in this study are attributed at least in part to the heterogeneity in surface water conditions over time. A conceptual framework envisioning a continuum between perennial and temporary rivers is proposed as a basis for ongoing research into these rivers. A supporting terminology for the range of river flow types in South Africa is presented.
- Full Text:
- Date Issued: 1998
Atterrissage
- Authors: TP Audiorama Orchestra (performers) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129611 , vital:36313 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-08
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
Paris 95
- Authors: TP Audiorama Orchestra (performers) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129596 , vital:36310 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-05
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998