Giraffe (Giraffa camelopardalis) are extralimital (non-native) to the Eastern Cape Province, South Africa yet they have and continue to be introduced to the region. Financial gain has arguably been the driving force behind these introductions as foreign tourists associate giraffe with Africa and the African wildlife experience. This raises a number of ethical, ecological and philosophical questions especially when it is considered that the impact of these browsers on the indigenous vegetation has remained largely unquantified. In this study I assessed the diet and potential impact of three populations of giraffe in the Eastern Cape Province between January 2002 and October 2003. The diet was assessed by both direct observations and faecal analysis. There was no significant difference (P > 0.05) between the results of the two methods of analysis, although direct observations appeared to be a superior method for assessing the diet of giraffe. The diet of giraffe in the Eastern Cape Province was similar to that within their native range with a deciduous species from the genus Acacia (Acacia karroo) being the most important component of the diet. However, giraffe in the Eastern Cape Province consumed more evergreen plant species than those within their native range. The relative lack of deciduous species in the Eastern Cape Province provides a likely explanation for such a result. Seasonal variation in the consumption of the most important species in the diet was evident and this was attributed to the deciduous nature of A. karroo and the seasonal growth of new shoots which were more palatable. The vegetation of the areas most commonly utilised by giraffe at each site was sampled using the point-centred-quarter method and the results related to the frequency of each species in the diet to calculate preference indices. Giraffe preference was strongest for A. karroo and this was attributed to the highly favourable chemical composition of the species. The browse utilisation of giraffe at each site was determined using the twig-length method and intake rates for the three most important species in the diet calculated using a pre-existing regression equation. Male giraffe fed at a higher rate than females. This was probably due to males adopting a “time-minimising” strategy to their feeding in order to allow more time for reproductive pursuits. Giraffe browse utilisation was highest where giraffe density was highest. However, several species were more heavily browsed than others even when giraffe density was low, suggesting that giraffe are capable of negatively affecting the indigenous flora of the province. I conclude that giraffe numbers should be reduced relative to property size in the Eastern Cape Province and that research into the impact of not only giraffe but the combined effects of giraffe and other extralimital herbivores on the indigenous flora and fauna be continued.

The multiple benefits from livestock production to rural households are evaluated in Thorndale, a communal area of the Limpopo Province South Africa. Monetary values of livestock products are presented. Values from most previous studies are static (and thus outdated), as a result of conceptual and methodological shifts. The net monetary value of the direct benefits from livestock was estimated as $656 per household/annum, excluding the holding of cattle for savings. The net value is equivalent to 22.7% of the value of the other livelihood sources that were considered, and inclusive of cash income streams, crops, and secondary woodland resources. A net 168% herd increase in livestock was recorded between 1993 and 1999. More households owned goats compared to cattle, and cattle were important for use as draught power, and for milk. Households without livestock benefited through gifts and services, valued at $33 per household/annum. Policy concerns are the provision of adequate market and pricing mechanisms for communal area livestock, tailored savings, investment support, credit schemes, and infrastructure. An appropriate multipurpose benefit production model, other than a commercialised model is suggested for the sector.

Alkaline precipitation of heavy metals from acidic water streams is a popular and long standing treatment process. While this process is efficient it requires the continuous addition of an alkaline material, such as lime. In the long term or when treating large volumes of effluent this process becomes expensive, with costs in the mining sector routinely exceeding millions of rands annually. The process described below utilises alkalinity generated by the alga Spirulina sp., in a continuous system to precipitate heavy metals. The design of the system separates the algal component from the metal containing stream to overcome metal toxicity. The primary treatment process consistently removed over 99% of the iron (98.9 mg/l) and between 80 and 95% of the zinc (7.16 mg/l) and lead (2.35 mg/l) over a 14-day period (20 l effluent treated). In addition the pH of the raw effluent was increased from 1.8 to over 7 in the post-treatment stream. Secondary treatment and polishing steps depend on the nature of the effluent treated. In the case of the high sulphate effluent the treated stream was passed into an anaerobic digester at a rate of 4 l/day. The combination of the primary and secondary treatments effected a removal of over 95% of all metals tested for as well as a 90% reduction in the sulphate load. The running cost of such a process would be low as the salinity and nutrient requirements for the algal culture could be provided by using tannery effluent or a combination of saline water and sewage. This would have the additional benefit of treating either a tannery or sewage effluent as part of an integrated process.

New hardware devices are continually being released to the public by hardware manufactures around the world. For these new devices to be usable under a PC operating system, device drivers that extend the functionality of the target operating system have to be constructed. This work examines and compares the device driver architectures currently in use by two of the most widely used operating systems, Microsoft’s Windows and Linux. The IEEE1394 (high speed serial bus) device driver stacks on each operating system are examined and compared as an example of a major device driver stack implementation, including driver requirements for the upcoming IEEE1394.1 bridging standard.

This study examines the utility of the MMPI-2 in predicting responsibility in pre-trial forensic patients, using a post hoc sample of 94 offenders from Sterkfontein Psychiatric Hospital in Gauteng. Firstly, the overall characteristics of the pre-trial forensic patients are discussed, following an analysis of demographic, clinical, criminal and MMPI-2 pre-trial data, as well as an overview of the Megargee typological classification of offenders. The sample is classified into Criminally Responsible (CR), Diminished Criminal Responsibility (DCR) and Not Criminally Responsible (NCR), and the CR and DCR groups are collapsed (CR/DCR) for many of the analyses when comparing them to the NCR group. Secondly, the variance of variables with responsibility is discussed, after examining one-way ANOVA’s of demographic, clinical, criminal and MMPI-2 variables, as well as an overview of high point pairs. Thirdly, discriminant analyses were conducted of demographic, clinical and MMPI-2 variables. When comparing the collapsed CR/DCR group to the NCR group, psychiatric diagnosis, presence of psychosis, the MMPI-2 Pa and Es scales, as well as race and substance abuse each had unique predictive power and created a substantial discriminative equation (F (6,70) = 45.732, p <0.0005) with a successful prediction rate of 96%. Using only MMPI-2 variables to predict responsibility showed significant unique contributions for the Pa, Es, MAC-R and Mf scales, with the BIZ scale not quite significant, and a fairly significant overall discriminant equation (F (5,73) = 6.474, p < 0.0005), with an overall successful prediction rate of 82%, with the MMPI-2 variables adding an additional 3% to the predictive power of the demographic and clinical variables. Similarly, when examining the more complex 3 group responsibility classification of CR, DCR and NCR, it was found that the demographic, clinical and MMPI-2 variables of psychiatric diagnosis, psychosis, race, substance abuse, and the Pa, Es and Ma scales all had significant contributions to a powerful discriminant analysis (F (14, 136) = 19.758, p < 0.0005) that was capable of correctly reclassifying almost 95% of the sample, and the MMPI-2 variables providing an increase in predictive power of 8%. Differences in responsible and not responsible pre-trial forensic patients are discussed, as well as the role of the MMPI-2 in assessing these differences, and the fact that it is highly likely that it adds more to the forensic assessment of responsibility than a 3% (CR/DCR versus NCR) or 8% (CR versus DCR versus NCR) increase in predictive power. Limitations of the study are discussed, together with recommendations for future research with the MMPI-2 for assessment of criminal responsibility. The suggestion is made that the MMPI-2 can become a valuable tool in South African forensic settings, not only in the assessment of responsibility and malingering, but also in the placement, management, follow-up and treatment of offenders, to maximize the limited resources in South Africa allocated for the rehabilitation of offenders, and minimize the risk of recidivism or rehospitalization.

The 70 kDa heat shock proteins (Hsp70s) are vital for normal protein folding, as they stabilise the unfolded state of nascent polypeptides, allowing these sufficient time to attain a correct tertiary structure. Hsp70s are aided by the DnaJ-like family of proteins, which interact with Hsp70s in order to enhance the chaperone activity of these proteins. DnaJ-like proteins contain a J domain, a seventy amino acid domain consisting of four α-helices, which is defined by the presence of an invariant tripeptide of histidine, proline and aspartic acid (HPD motif). This motif is key to the interaction between DnaJ-like proteins and Hsp70s. This thesis has focused on determining the presence of other conserved residues in the J domain and their role in mediating the interaction of DnaJ-like proteins with partner Hsp70s. DnaJ-like proteins from Agrobacterium tumefaciens RUOR were isolated and used as a model system. A. tumefaciens DnaJ (Agt DnaJ) was able to replace the lack of E. coli DnaJ in an E. coli null mutant strain, however, additional A. tumefaciens DnaJ-like proteins Agt DjC1/DjlA, Agt DjC2 and Agt DjC5 were unable to complement for the lack of E. coli DnaJ. Replacement of the Agt DnaJ J domain with J domains from these proteins resulted in non-functional chimeric proteins, despite some sequence conservation. The kinetics of the basal specific ATPase activity of Agt DnaK, and its ability to have this activity stimulated by Agt DnaJ and Agt DnaJ-H33Q were also investigated. Stimulation of the ATPase activity by Agt DnaJ ranged between 1.5 to 2 fold, but Agt DnaJ-H33Q was unable to stimulate the basal ATPase activity. Conserved amino acids in the J domain were identified in silico, and these residues were substituted in the J domain of Agt DnaJ. The ability of these derivative proteins to replace E. coli DnaJ was investigated. Alterations in the HPD motif gave rise to proteins unable to complement for lack of E. coli DnaJ, consistent with literature. Agt DnaJ-R26A was unable to replace E. coli DnaJ suggesting that Arg26 could be key to the interaction with partner Hsp70s. Agt DnaJ-D59A was unable to replace E. coli DnaJ; substitutions in Asp59 have not previously been shown to impact on the function of DnaJ. Substituting Arg63 in Agt DnaJ abrogated the levels of complementation. Substitution of several structural residues was also found to disrupt the in vivo function of Agt DnaJ suggesting that the maintenance of the structural integrity of the J domain was important for function. This study has identified a number of residues critical to the structure and function of the J domain of Agt DnaJ, and potentially of general importance as molecular determinants for DnaJ-Hsp70 interaction.

Plamodium falciparum heat shock protein (PfHsp70) is believed to be involved in the cytoprotection of the malaria parasite through its action as a molecular chaperone. Bioinformatic analysis reveal that PfHsp70 consists of the three canonical Hsp70 domains; an ATPase domain of 45 kDa, Substrate binding domain of 15 kDa and a C-terminal domain of 10 kDa. At the C-terminus there is a GGMP repeat motif that is commonly found in Hsp70s of parasitic origins. Plasmodium falciparum genome is 80% A-T rich, making it difficult to recombinantly express its proteins in Escherhia coli (E. coli) as a result of rare codon usage. In this study we carried out experiments to improve expression in E. coli by inserting the PfHsp70 coding region into the pQE30 expression vector. However multiple bands were detected by Western analysis, probably due to the presence of rare codons. The RIG plasmid, which encodes tRNAs for rare codons in particular Arg (AGA/AGG), Ile (AUA) and Gly (GGA) was engineered into the E. coli strain resulting in production of full length PfHsp70. Purification was achieved through Ni^(2+) Chelating sepharose under denaturing conditions. PfHsp70 was found to have a very low basal ATPase activity of 0.262 ± 0.05 nmoles/min/mg of protein. In the presence of reduced and carboxymethylated lactalbumin (RCMLA) a 11-fold increase in ATPase activity was noted whereas in the presence of both RCMLA and Trypanosoma cruzi DnaJ (Tcj2) a 16-fold was achieved. For ATP hydrolysis kcat value of 0.003 min^(-1) was obtained whereas for ADP release a greater k_cat_ value of 0.8 min^(-1) was obtained. These results indicated that rate of ATP hydrolysis maybe the rate-determining step in the ATPase cycle of PfHsp70.

Cognisant of the fact that counselling has become an essential aspect of dealing with HIV/AIDS in South Africa, the researcher aimed to explore the stressors experienced by HIV/AIDS counsellors. It was envisioned that the results obtained would both help to improve the counselling services provided at Settlers Hospital, and assist other organisations to do so. The research focused on how the participants dealt with the dual roles of non-directive listening and the more prescriptive advice-giving, the stressors they experienced and the support structures they had, or needed, to assist them in being more effective HIV/AIDS counsellors. The sample consisted of four HIV/AIDS counsellors working at Settlers Hospital, Grahamstown. The co-ordinator of HIV/AIDS at the hospital was interviewed for collateral information. A qualitative, multiple case study was undertaken. In-depth, semi-structured interviews were used to collect the data which were recorded and transcribed and then constructed into coherently organised personal narratives of each participant’s experiences. A composite description of all the results was arrived at through the use of a reading guide which reduced the data into a thematic content analysis. The analysed data served to present an understanding of the counsellors’ experiences and to enable recommendations to be made which could assist them in pursuing their work more effectively. The findings of this study indicate that HIV/AIDS counselling is an emotionally stressful occupation. Contributory factors include the twofold role of promoting prevention and serving as empathic listeners. Other stressors derive from issues of confidentiality and stigma concerning HIV/AIDS, counsellors’ identification with clients’ experiences and the demographics of HIV/AIDS in South Africa. Situational stressors which arise from working as both nurses and counsellors in a public health institution were also identified. Recommendations are made to alleviate the counsellors’ stress in the form of facilitated emotional support groups, professional supervision, managerial support to improve the working environment, and ongoing in-service training.

We report on the design, implementation and performance issues of the DRUBIS (Distributed Rhodes University Biometric Identification System) experimentation framework. The Principal Component Analysis (PCA) face-recognition approach is used as a case study. DRUBIS is a flexible experimentation framework, distributed over a number of modules that are easily pluggable and swappable, allowing for the easy construction of prototype systems. Web services are the logical means of distributing DRUBIS components and a number of prototype applications have been implemented from this framework. Different popular PCA face-recognition related experiments were used to evaluate our experimentation framework. We extract recognition performance measures from these experiments. In particular, we use the framework for a more indepth study of the suitability of the DFFS (Difference From Face Space) metric as a means for image classification in the area of race and gender determination.

Thermoluminescence characteristics of two subsidiary glow peaks, one below 100°C and the other above 300°C, have been studied for measurements between 30°C and 500°C in α-Al_2_O_3_:C. The thermoluminescence intensity of the lower temperature peak decreased with storage with a half-life of about 150 s. In contrast, the intensity of the higher temperature peak increased with storage towards some maximum. The peak-temperature of each of the secondary glow peaks was essentially constant with dose, whereas that of the main peak decreased with irradiation. The dose response for the three peaks was similar except for sublinear growth in the higher temperature peak at low dose values. These effects are discussed in terms of changes in the concentration of F+ luminescence precursors brought about by competitive electron retrapping at deep electron-traps or hole-traps. This work refines the physics and application of α-Al_2_O_3_:C luminescence in radiation dosimetry.