Showing items 641 - 660 of 683

Your selections:

Toward the development of a rearing protocol for juvenile dusky kob, Argyrosomus japonicus (Pisces: Sciaenidae)

  • Authors: Collett, Paul David
  • Date: 2008
  • Subjects: Argyrosomus -- South Africa , Mariculture -- South Africa , Fishes -- Nutrition -- South Africa , Fishes -- Growth -- South Africa , Fish trade -- South Africa , Sciaenidae
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5325 , http://hdl.handle.net/10962/d1005171 , Argyrosomus -- South Africa , Mariculture -- South Africa , Fishes -- Nutrition -- South Africa , Fishes -- Growth -- South Africa , Fish trade -- South Africa , Sciaenidae
  • Description: The South African mariculture industry is developing the rearing technology of indigenous fish species. Dusky kob (Argyrosomus japonicus) has high-quality flesh and a good market demand. Research is needed to determine the environmental requirements under which growth of dusky kob is optimised. This study assessed the effect of temperature, light intensity, feeding frequency and stocking density, respectively, on growth, feed conversion ratio (FCR) and survival of juvenile dusky kob within a weight range of 10-60 g fish⁻¹) in a series of four growth trials. The effect of temperature on growth and FCR was assessed at 14 temperatures from 17 to 28°C. The temperature for best growth was estimated to be 25.3 °C, while 21.4 °C was the temperature at which the best FCR was achieved. A growth trial testing the effect of light intensity on growth showed that light intensity did not affect growth in the range of 23 – 315 lx. Fish fed a restricted ration of 3.6% body weight per day (chapter 2) or 3.41% body weight per day (chapter 4) had a better FCR than fish fed to satiation. A trial to assess the effect of feeding frequency on growth and FCR showed that fish fed both two or three times daily grew better than those fed once daily. FCR was best in fish that were fed once or twice daily. Preliminary analysis of the results from a stocking density trial showed that stocking density in the range of 10 – 50 kg m⁻³ did not affect growth of juvenile dusky kob. It is recommended to culture dusky kob at a temperature of 25.3 - 21.4 °C at stocking densities up 50 kg m⁻³ to maximise growth. However, a study is needed to determine the environmental conditions needed to maximise profit under commercial conditions. The results allow the South African industry the opportunity to assess the culture potential of this species. In addition, the results will help develop protocols that can be used in other South African candidate aquaculture species such as silver kob, yellowtail, white-stumpnose and sole.
  • Full Text:
  • Date Issued: 2008

Towards a corpus of Indian South African English (ISAE) : an investigation of lexical and syntactic features in a spoken corpus of contemporary ISAE

  • Authors: Pienaar, Cheryl Leelavathie
  • Date: 2008
  • Subjects: English language -- South Africa Computational linguistics -- Methodology Discourse analysis -- Data processing English language -- Syntax -- South Africa English language -- Usage -- South Africa East Indians -- South Africa -- Language Lexicology
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2357 , http://hdl.handle.net/10962/d1002640
  • Description: There is consensus among scholars that there is not just one English language but a family of “World Englishes”. The umbrella-term “World Englishes” provides a conceptual framework to accommodate the different varieties of English that have evolved as a result of the linguistic cross-fertilization attendant upon colonization, migration, trade and transplantation of the original “strain” or variety. Various theoretical models have emerged in an attempt to understand and classify the extant and emerging varieties of this global language. The hierarchically based model of English, which classifies world English as “First Language”, “Second Language” and “Foreign Language”, has been challenged by more equitably-conceived models which refer to the emerging varieties as New Englishes. The situation in a country such as multi-lingual South Africa is a complex one: there are 11 official languages, one of which is English. However the English used in South Africa (or “South African English”), is not a homogeneous variety, since its speakers include those for whom it is a first language, those for whom it is an additional language and those for whom it is a replacement language. The Indian population in South Africa are amongst the latter group, as theirs is a case where English has ousted the traditional Indian languages and become a de facto first language, which has retained strong community resonances. This study was undertaken using the methodology of corpus linguistics to initiate the creation of a repository of linguistic evidence (or corpus), of Indian South African English, a sub-variety of South African English (Mesthrie 1992b, 1996, 2002). Although small (approximately 60 000 words), and representing a narrow age band of young adults, the resulting corpus of spoken data confirmed the existence of robust features identified in prior research into the sub-variety. These features include the use of ‘y’all’ as a second person plural pronoun, the use of but in a sentence-final position, and ‘lakker’ /'lVk@/ as a pronunciation variant of ‘lekker’ (meaning ‘good’, ‘nice’ or great’). An examination of lexical frequency lists revealed examples of general South African English such as the colloquially pervasive ‘ja’, ‘bladdy’ (for bloody) and jol(ling) (for partying or enjoying oneself) together with neologisms such as ‘eish’, the latter previously associated with speakers of Black South African English. The frequency lists facilitated cross-corpora comparisons with data from the British National Corpus and the Corpus of London Teenage Language and similarities and differences were noted and discussed. The study also used discourse analysis frameworks to investigate the role of high frequency lexical items such as ‘like’ in the data. In recent times ‘like’ has emerged globally as a lexicalized discourse marker, and its appearance in the corpus of Indian South African English confirms this trend. The corpus built as part of this study is intended as the first building block towards a full corpus of Indian South African English which could serve as a standard for referencing research into the sub-variety. Ultimately, it is argued that the establishment of similar corpora of other known sub-varieties of South African English could contribute towards the creation of a truly representative large corpus of South African English and a more nuanced understanding and definition of this important variety of World English.
  • Full Text:
  • Date Issued: 2008

Towards a taxonomy of network scanning techniques

  • Authors: Barnett, Richard J , Irwin, Barry V W
  • Date: 2008
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/430310 , vital:72682 , https://doi.org/10.1145/1456659.1456660
  • Description: Network scanning is a common reconnaissance activity in network in-trusion. Despite this, it's classification remains vague and detection sys-tems in current Network Intrusion Detection Systems are incapable of detecting many forms of scanning traffic. This paper presents a classi-fication of network scanning and illustrates how complex and varied this activity is. The presented classification extends previous, well known, definitions of scanning traffic in a manner which reflects this complexity.
  • Full Text:
  • Date Issued: 2008

Towards a user centric model for identity and access management within the online environment

  • Authors: Deas, Matthew Burns
  • Date: 2008
  • Subjects: Computers -- Access control , Computer networks -- Security measures
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:9780 , http://hdl.handle.net/10948/775 , Computers -- Access control , Computer networks -- Security measures
  • Description: Today, one is expected to remember multiple user names and passwords for different domains when one wants to access on the Internet. Identity management seeks to solve this problem through creating a digital identity that is exchangeable across organisational boundaries. Through the setup of collaboration agreements between multiple domains, users can easily switch across domains without being required to sign in again. However, use of this technology comes with risks of user identity and personal information being compromised. Criminals make use of spoofed websites and social engineering techniques to gain illegal access to user information. Due to this, the need for users to be protected from online threats has increased. Two processes are required to protect the user login information at the time of sign-on. Firstly, user’s information must be protected at the time of sign-on, and secondly, a simple method for the identification of the website is required by the user. This treatise looks at the process for identifying and verifying user information, and how the user can verify the system at sign-in. Three models for identity management are analysed, namely the Microsoft .NET Passport, Liberty Alliance Federated Identity for Single Sign-on and the Mozilla TrustBar for system authentication.
  • Full Text:
  • Date Issued: 2008

Towards revised physically based parameter estimation methods for the Pitman monthly rainfall-runoff model

  • Authors: Kapangaziwiri, Evison , Hughes, Denis A
  • Date: 2008
  • Language: English
  • Type: text , Article
  • Identifier: vital:7088 , http://hdl.handle.net/10962/d1012417
  • Description: This paper presents a preliminary stage in the development of an alternative parameterisation procedure for the Pitman monthly rainfall runoff model which enjoys popular use in water resource assessment in Southern Africa. The estimation procedures are based on the premise that it is possible to use physical basin properties directly in the quantification of the soil moisture accounting, runoff, and recharge and infiltration parameters. The results for selected basins show that the revised parameters are at least as good as current regionalised sets or give satisfactory results in areas where no regionalised parameters exist.
  • Full Text:
  • Date Issued: 2008

Towards the bioremediation of the hypertrophic Swartkops Solar Salt-works

  • Authors: Difford, Mark
  • Date: 2008
  • Subjects: Salt industry and trade -- South Africa -- Port Elizabeth , Bioremediation
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:10606 , http://hdl.handle.net/10948/1506 , Salt industry and trade -- South Africa -- Port Elizabeth , Bioremediation
  • Description: This thesis presents the results of three studies aimed at improving brine-quality at the Swartkops solar salt-works (Swartkops Sea Salt [Pty] Ltd) on the outskirts of Port Elizabeth, South Africa. This is a highly eutrophic salt-works, the management of which has become increasingly difficult in recent years. The fundamental problem is how best to operate the system at maximum capacity while limiting nutrient inputs from the nutrient-rich microtidal Swartkops Estuary. In the first study, brine-quality at several sites along the axis of the Swartkops Estuary, and the extent to which it is affected by a variety of factors, is compared. Sites were sampled on micro- and macrotidal time scales, and were selected by the management of the salt-works as possible locations for a new pump-house (for extracting brine from the estuary) for their salt-work operations at Swartkops and Missionvale. The study showed that there are incremental benefits to be had from moving the site of extraction downstream from its present position to a site closer to the mouth of the estuary, where the concentration of nutrients usually is lower and where salinity usually is higher. There is little to be gained from moving the site of extraction laterally, to the mouth of the Inlet from which brine currently is extracted, so that brine is extracted directly from the estuary itself. A set of models relating the concentrations of NH+ 4 , NO{u100000}3 , and PO34{u100000} to salinity is proposed. These take into account the influences of site and season and may be used to estimate the concentration of these nutrients from a measurement of salinity. The model for PO34{u100000} shows that it would be more damaging to the salt-works’ operations to pump “low”-salinity brine during the early months of summer than during autumn. Evidence is also presented to show that Wylde Bridge has no influence on nutrient concentrations in the estuary, with tidal flushing generally passing beyond the Wylde-Bridge break-point. The exceptionally heavy flooding of the estuary that occurred in September 2002 may, however, have biased this conclusion, because of its scouring effect. The second study concentrated on monitoring the effect of (1) decreasing pond depth and (2) increasing pond salinity—two readily available management tools—on brine quality at the salt-works. Pond depth throughout the salt-works was decreased by 40 cm, and the salinity of Pond 5, a pond in the middle of the system, was increased to 175 S. Both measures were kept in place for the duration of the study (Nov. 2002–Aug. 2004). The pond-depth experiment did not have the expected result, there being no evidence of the increase in microalgal growth in the water column that was predicted based on previous research. There was, however, a significant increase in benthic chlorophyll-a, and there was a general improvement in the condition of the sedimentary system of the salt-works. There was also a substantial decrease in particulate organic matter in the water column, with clear evidence that the remaining fraction was closely associated with living forms of particulate matter rather than with detritus. The pond-salinity experiment proves that there is a flourishing, and resilient, population of brine shrimp (Artemia salina L.) at the salt-works. Restocking the salina, or stocking it with a different strain of brine shrimp, is therefore not necessary. The results of this study show that the brine shrimp population at the salt-works needs salinities of greater than about 65–70 S to survive. As a living force they almost certainly need a protective salinity that is greater than about 120–140 S, perhaps even as great as 160 S. Brine shrimp thrived in the high salinity milieu of the experimental pond for the duration of the study, but dwindled from three other ponds of the system once their salinities fell to below 90 S, eventually to disappear from them, apparently completely, once salinity fell to below 65 S. The third and final study concentrated on establishing whether the products released by decomposing barley straw could be used in a solar salt-works to control macroalgal blooms without detrimentally affecting the benthic-mat. Previous research has shown that these products are effective inhibitors of macroalgal growth and that they remain effective under saline conditions. The results presented here show that the same products, or products released under similar conditions of decomposition, adversely effect both the structure and the function of the mat. Consequently, their use in a solar salt-works cannot be recommended.
  • Full Text:
  • Date Issued: 2008

Towards the development of InAs/GaInSb strained-layer superlattices for infrared detection

  • Authors: Botha, Lindsay
  • Date: 2008
  • Subjects: Gallium arsenide semiconductors , Indium alloys , Compound semiconductors , Organometallic compounds , Infrared detectors , Infrared technology , Superlattices as materials
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10526 , http://hdl.handle.net/10948/713 , Gallium arsenide semiconductors , Indium alloys , Compound semiconductors , Organometallic compounds , Infrared detectors , Infrared technology , Superlattices as materials
  • Description: This study focuses on the development of InAs/GaInSb strained-layer superlattice structures by metal organic chemical vapour deposition (MOCVD), and deals with two aspects of the development of InAs/GaInSb SLS’s by MOCVD viz. the deposition of nano-scale (~100 Å) GaInSb layers, and the electrical characterization of unstrained InAs. The first part of this work aims to study the MOCVD growth of GaInSb layers in terms of deposition rate and indium incorporation on the nano-scale. This task is approached by first optimizing the growth of relatively thick (~2 μm) epitaxial films, and then assuming similar growth parameters during nano-scale deposition. The GaInSb layers were grown as part of GaInSb/GaSb quantum well (QW) structures. By using this approach, the GaInSb QW’s (~100 Å) could be characterized with the use of photoluminescence spectroscopy, which, when used in conjunction with transmission electron microscopy and/or X-ray diffractomery, proves useful in the analysis of such small scale deposition. It is shown that the growth rate of GaInSb on the nano-scale approaches the nominal growth rates determined from thick (~2 μm) GaInSb calibration layers. The In incorporation efficiency in nano-layers, however, was markedly lower than what was predicted by the GaInSb calibration layers. This reduction in indium incorporation could be the result of the effects of strain on In incorporation. The choice of substrate orientation for QW deposition was also studied. QW structures were grown simultaneously on both (100) and 2°off (100) GaSb(Te) substrates, and it is shown that growth on non-vicinal substrates is more conducive to the deposition of high quality QW structures. The second part of this study focuses on the electrical characterization of unstrained InAs. It is long known that conventional Hall measurements cannot be used to accurately characterize InAs epitaxial layers, as a result of parallel conduction resulting from surface and/or interface effects. This study looks at extracting the surface and bulk electrical properties of n-type InAs thin films directly from variable magnetic field Hall measurements. For p-type InAs, the situation is complicated by the relatively large electron to hole mobility ratio of InAs which tends to conceal the p-type nature of InAs thin films from Hall measurements. Here, this effect is illustrated by way of theoretical simulation of Hall data.
  • Full Text:
  • Date Issued: 2008

Towards understanding the mechanism of dimerisation of Saccharomyces cerevisiae eukaryotic translation initiation factor 5A

  • Authors: Gentz, Petra Monika
  • Date: 2008
  • Subjects: Cytology Molecular biology Biochemistry Proteins -- Analysis Proteomics Polypeptides Amino acids -- Synthesis
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:3992 , http://hdl.handle.net/10962/d1004052
  • Description: Eukaryotic translation initiation factor 5A (eIF5A) is the only known protein to contain hypusine, formed by post-translational modification of a highly conserved lysine residue. Hypusination is essential for eIF5A function, being required for binding of a specific subset of mRNAs necessary for progression of eukaryotic cells through the G1-S checkpoint. Little structural information is available for eIF5A other than that derived from archaeal homologues. The aim of this study was to conduct structure-function studies on Saccharomyces cerevisiae (yeast) eIF5A, encoded by TIF51A. Homology models of eIF5A were generated from the Methanococcus jannaschii archaeal homologue (aIF5A) and two Leishmania eIF5As. The models, along with secondary structure predictions identified an a-helix on the C-terminal domain, unique to eukaryote eIF5A. The Neurospora crassa structural analogue, HEX-1, which dimerises in three configurations, was used to generate similar dimeric model configurations of eIF5A. A biochemical and functional analysis was used to validate the homology models of eIF5A.Since the crystal structures of aIF5A and eIF5A were solved from unhypusinated protein produced in Escherichia coli, 6 x His-tagged eIF5A (His-eIF5A) was used for biochemical analysis. This analysis revealed that eIF5A existed as a dimer in solution, dependent on the presence of the highly conserved Cys 39 residue. A yeast TIF51A/TIF51B null yeast strain, with a chromosomal copy of TIF51A under control of PGAL1, was used to confirm that HiseIF5A and selected eIF5A mutants were functional in vivo. Biochemical analysis showed that hypusinated His-eIF5A also exists as a dimer, but neither the dimerisation, nor the function of eIF5A are dependent on the presence of Cys 39. Rather they depend on the presence of hypusine (Hpu) 51 and the presence of RNA leading to the conclusion that RNA and hypusine are required for dimerisation and hence function, of native eIF5A in vivo. In contrast, a Lys 51 to Arg 51 substitution or RNase treatment of His-eIF5A produced in E. coli did not destabilize the dimeric form, suggesting different folding/dimerisation mechanisms in E. coli and yeast cells. The information obtained from the initial homology models, together with the results of the biochemical analysis was used to propose a mechanism for dimerisation of yeast eIF5A involving both hypusine and RNA.
  • Full Text:
  • Date Issued: 2008

Tracing and erasure in Kathryn Smith's Psychogeographies: the washing away of wrongs

  • Authors: de Jager, Maureen
  • Date: 2008
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/147413 , vital:38634 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC31057
  • Description: Kathryn Smith's Psychogeographies: The Washing Away of Wrongs is a series of twelve prints comprising photographs and handwritten text, wherein she records her 'pilgrimage' to the former homes of British serial killer Dennis Nilsen. As such, it utilises photographic and autographic traces to 'track' the elusive traces left by Nilsen. Given the lapse of two decades between Nilsen's arrest and Smith's visit, the traces of Nilsen's 'wrongs' seem all but erased by the banal façade of suburban living which has continued on, regardless. In taking this as a starting point, the following article considers the motif of absence that characterises Smith's work as intrinsic to traces per se.
  • Full Text:
  • Date Issued: 2008

Transitions towards a knowledge society: Aspectual pre-evaluation of a culture-sensitive implementation framework

  • Authors: Thinyane, Mamello , Terzoli, Alfredo , Clayton, Peter G
  • Date: 2008
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/431054 , vital:72741 , https://doi.org/10.1007/978-0-387-09729-9_41
  • Description: Information and Communication Technology (ICT) is aiding the transi-tion of society into information society and ultimately knowledge society. Embedded within ICT are the cultural and philosophical undercurrents of the society in which the ICT solutions are developed, currently pre-dominantly the Western culture. The proliferation of ICT is therefore in-advertedly leading to more Westernization of the world. It is important, therefore, that ICT solutions are culture sensitive and flexible enough to be situated within different cultures. To that end, we utilize Herman Dooyeweerd’s Theory of Modal Aspects to analyze a framework we has developed for implementation of locally situated knowledge based systems, to determine its efficacy in addressing the different modal as-pects, which make up the total experience and cultural expressiveness of societies.
  • Full Text:
  • Date Issued: 2008

Treatment and care of children and adolescents diagnosed with Attention deficit/Hyperactivity disorder

  • Authors: Snyman, Sanmari
  • Date: 2008
  • Subjects: Attention-deficit disorder in adolescence , Hyperactive children -- South Africa -- Port Elizabeth
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10144 , http://hdl.handle.net/10948/871 , Attention-deficit disorder in adolescence , Hyperactive children -- South Africa -- Port Elizabeth
  • Description: Background: In recent years the incidence of Attention Deficit/Hyperactivity Disorder (ADHD) has increased. Objectives: The primary aim of the study was to determine the treatment of children and adolescents diagnosed with ADHD in South Africa and more specifically the Eastern Cape. Methods: The study consisted of two parts, a retrospective drug utilisation study and a questionnaire survey. The drug utilisation study was conducted on chronic medication records of a private sector medical scheme administrator and contained records from 1994 to 2006. A total of 42 250 records representing 8 274 patients and 4 001 families, were analysed. The questionnaire survey was conducted in the Eastern Cape. The questionnaires were distributed by responsible pharmacists to parents of children receiving medication for the treatment of ADHD from his/her pharmacy. Fifty one completed questionnaires were analysed. Results: The average age of patients in the drug utilisation study were 14.28 (SD = 5.50) years. Males represented 77.37 percent of patients. Ritalin® 10 mg was the most frequently prescribed methylphenidate-containing product, followed by Ritalin® LA 20 mg. The two most frequently prescribed active ingredients apart from methylphenidate were fluticasone and budesonide. The two most common comorbid conditions were allergic rhinitis and asthma. The average age of patients in the questionnaire survey was 10.26 (SD = 2.51) years. Males represented 73.58 percent of patients. A third of patients had relatives previously diagnosed with ADHD. Ritalin® 10 mg was the most frequently prescribed methylphenidate-containing product. Conclusion: ADHD is a complex life-long disorder. It does not only affect the child diagnosed with the disorder, but also has effects on the family, schooling system and peer relationship. Therefore, more studies regarding the incidence and treatment of ADHD need to be conducted in South Africa.
  • Full Text:
  • Date Issued: 2008

Trends and determinants of inward foreign direct investment to South Africa

  • Authors: Rusike, Tatonga Gardner
  • Date: 2008
  • Subjects: International business enterprises -- South Africa , Investments, Foreign -- South Africa , Economic development -- South Africa , Macroeconomics -- South Africa , Foreign exchange rates -- South Africa
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: vital:995 , http://hdl.handle.net/10962/d1002730 , International business enterprises -- South Africa , Investments, Foreign -- South Africa , Economic development -- South Africa , Macroeconomics -- South Africa , Foreign exchange rates -- South Africa
  • Description: Foreign direct investment (FDI) is seen as a way to provide the needed capital inflow to stimulate growth in a domestic economy. FDI can also result in increased employment levels, managerial skills and increase in technology. In efforts to attract FDI, host countries have undertaken various policy incentives to attract foreign investors. This study analyses the trends and determinants of inward FDI to South Africa for the period 1975-2005. The study starts by reviewing FDI literature on its determinants and provides the macroeconomic background and FDI related policies undertaken in South Africa. The trend and sectoral analysis provides the actual nature of FDI flows to South Africa. An empirical model linking theoretical and empirical determinants of FDI is estimated using the Johansen cointegration and VECM framework. The study also augments the cointegration framework with impulse response and variance decomposition analyses to complement the long and short run determinants of FDI. Dummy variables are used in each of the estimated FDI models to take into account the possibility of structural breaks. Results show that relative to the size of the economy and to other developing countries, South Africa still receives low levels of inward FDI. Only are few years are exceptional i.e. 1997, 2001 and 2005. From the sectoral distribution, the financial sector is now the major recipient of FDI followed by the mining and manufacturing sectors. The emergence of the financial sector could suggest that FDI motives could have shifted from the natural resource seeking and market seeking to efficiency seeking FDI. The United Kingdom emerges as the major source of FDI to South Africa followed by United States of America and Germany. Empirical analysis indicated that openness, exchange rate and financial development are important long run determinants of FDI. Increased openness and financial development attract FDI while an increase (depreciation) in the exchange rate deters FDI to South Africa. Market size emerges as a short run determinant of FDI although it is declining in importance. Most of the impulse response analysis confirmed the VECM findings. Variance decomposition analysis showed that FDI itself, imports and exchange rate explain a significant amount of the forecast error variance. The influence of market size variable is small and declining over time.
  • Full Text:
  • Date Issued: 2008

Tripping over our own feet : a critical discussion of Trade Related Intellectual Property Rights (TRIPS) with specific reference to their impact on South Africa's ability to combat HIV and AIDS

  • Authors: Brennan, Jade
  • Date: 2008
  • Subjects: Agreement on Trade-Related Aspects of Intellectual Property Rights, (1994) Trade regulation -- South Africa Intellectual property -- South Africa HIV (Viruses) -- South Africa AIDS (Disease) -- South Africa Patients -- Civil rights -- South Africa Human rights -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2850 , http://hdl.handle.net/10962/d1006316
  • Description: This thesis aims to look at the agreement on Trade Related Intellectual Property Rights (TRIPS) with specific reference to their impact on South Africa's ability to combat HIV and AIDS. It begins by looking at the history of patents and intellectual property rights and illustrates why and how the TRIPS Agreement came into existence. The TRIPS Agreement exemplifies the disparities between developed and developing countries and this can clearly be seen with regard to the provision of anti-HIV and AIDS drugs. The developing world deals with the bulk of the HIV and AIDS epidemic whilst the developed world holds most of the patents on the medication needed to treat those living with HIV and AIDS. This situation lends itself to a rift between patient rights on the one hand, and patent rights on the other. Traditionally the state has been the provider of rights such as health, but TRIPS alters this to include strong patent protection that is in line with neo liberal doctrine. The thesis examines these tensions with specific reference to South Africa's ability successfully to implement programmes to combat HIV and AIDS.
  • Full Text:
  • Date Issued: 2008

Tuning the redox properties of Co-N4 macrocyclic complexes for the catalytic electrooxidation of glucose

  • Authors: Villagra, Evelyn , Bedioui, Fethi , Nyokong, Tebello , Canales, J Carlos , Sancy, Mamie , Páez, Maritza A , Costamagna, Juan , Zagal, Jose H
  • Date: 2008
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/268675 , vital:54221 , xlink:href="https://doi.org/10.1016/j.electacta.2008.02.006"
  • Description: Graphite electrodes modified with four different cobalt N4 macrocyclics, namely Co tetrapentapyridinophthalocyanine, (CoTPenPyrPc), Co tetrapyridinoporphyrazine (CoTPyPz), Co octa(hydroxyethylthio)phthalocyanine (CoOEHTPc) and Co tetranitrophthalocyanine (CoTNPc) exhibit catalytic activity for the oxidation of glucose in alkaline media. The purpose of this work is to establish correlations between the catalytic activity of these complexes and their redox potential. The activity of the different modified electrodes was tested by linear voltammetry under hydrodynamic conditions using the rotating disk technique. Tafel plots constructed from mass-transport corrected currents give slopes ranging from 0.080 to 0.160 V/decade for the different catalysts which suggests that a first one-electron step is rate controlling with the symmetry of the energy barrier depending on the nature of the ligand of the Co complex. A plot of log I versus the Co(II)/(I) formal potential gives a volcano curve that also includes catalysts studied previously. This illustrates the concept that the formal potential of the catalyst needs to be tuned to a certain value for achieving maximum activity. A theoretical interpretation of these results is given in terms of Langmuir isotherms for the adsorption of glucose on the Co sites of the surface-confined metal complexes.
  • Full Text:
  • Date Issued: 2008

Underlying mechanisms affecting institutionalisation of environmental education courses in Southern Africa

  • Authors: Lupele, Justin
  • Date: 2008
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/386926 , vital:68188 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122773"
  • Description: This paper discusses the underlying causal mechanisms that enabled or constrained institutionalisation of environmental education in 12 institutions in eight countries in southern Africa. The study was carried out in the context of the Southern Africa Development Community Regional Environmental Education Support Programme’s Course Development Network (CDN). This paper reports on part of the author's doctoral study and draws on critical realism as the ontological lens. Data analysis was done by means of a retroductive mode of inference, as articulated by Danermark, Ekström, Jakosben and Karlsson (2002). The paper demonstrates that there are a number of underlying causal mechanisms, which may enable or constrain institutionalisation of environmental education. They include factors at play at both national and institutional level; namely, responsiveness to national and institutional needs, recognition and ownership, accreditation and certification, institutional culture and politics, short course support structure and support from colleagues. As part of the discussions of the results of the study, I have advanced some retroductive theories that suggest causal mechanisms beyond the empirical data based on the participants’ experiences and events in the CDN.
  • Full Text:
  • Date Issued: 2008

Understanding and improving the residual efficacy of the cryptophlebia leucotreta granulovirus (Cryptogran)

  • Authors: Kirkman, Wayne
  • Date: 2008
  • Subjects: Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Citrus -- Diseases and pests
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5794 , http://hdl.handle.net/10962/d1005482 , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Citrus -- Diseases and pests
  • Description: False codling moth (FCM), Thaumatotibia (=Cryptophlebia) leucotreta (Meyr) (Lepidoptera: Tortricidae), is one of the most important pests on citrus. The Cryptophlebia leucotreta granulovirus (CrleGV) has been developed into a successful biological control agent, registered under the name Cryptogran, and is currently the preferred product for the control of FCM on citrus in South Africa. A prerequisite to the continued success of Cryptogran as a means of controlling false codling moth is to understand the factors affecting field persistence of the virus, and to find ways to improve it. The aim of this study was to gain a clearer understanding of the product and the abiotic and biotic factors affecting its persistence in the field, and to investigate methods to improve this persistence. The effect of UV-irradiation on the virus was determined, and various products were tested as UV protectants in laboratory bioassays. Lignin was the most effective additive, and was tested in several field trials, where it also enhanced the efficacy of Cryptogran. Laboratory trials indicated that Cryptogran is rainfast. Cryptogran applications early in the season had a longer period of residual activity than sprays applied closer to harvest. Daytime applications were less effective that evening sprays. Sprays applied coinciding with peaks in pheromone moth trap catches were more effective than those applied between peaks. Biotic factors influencing persistence were investigated. Residual efficacy was longer when treatments were applied to blocks than as single tree treatments. Attempts were made to quantify the effect of the navel end of a navel orange on the field persistence of Cryptogran. Cryptogran was shown to be compatible with many agricultural chemicals used on citrus. Economic thresholds and various cost-benefit analyses are discussed. A list of practical recommendations to growers was drawn up, and possibilities for future research are presented.
  • Full Text:
  • Date Issued: 2008

Using assessment and reflexive teaching practices to inform and guide changes to the teaching and learning activities in Introductory Accounting

  • Authors: Bezuidenhout, L Peta
  • Date: 2008
  • Language: English
  • Type: Conference paper
  • Identifier: vital:6081 , http://hdl.handle.net/10962/d1008585
  • Description: Teaching accounting to first year university students in higher education institutions is becoming increasingly complex as we deal with increasing class sizes, increasing diversity and a student body which appears to be less inclined to study without external motivating factors, while to be successful in studying accounting requires more than passive learning. Our aim was to make our students active participants in their accounting studies. After studying established research into assessment and approaches to student learning, changes were made to our course to ensure increased and active participation from our students. Critical to this change was guiding students in making the shift from a surface approach to learning, to a deep approach to learning where they would engage with the subject matter in a manner more likely to result in truly understanding the concepts and principles being taught. An important part of implementing these changes was asking our students to evaluate the innovations after they had taken place. Feedback received from our students resulted in the use of a new and unplanned innovation in the form of the setting of regular mini-tests. This was arguably the most successful of all the interventions introduced during the year and resulted in our journey being more exciting and less predictable than expected.
  • Full Text:
  • Date Issued: 2008

Using assessment and reflexive teaching practices to inform and guide changes to the teaching and learning activities in Introductory Accounting

  • Authors: Bezuidenhout, L Peta
  • Date: 2008
  • Subjects: To be catalogued
  • Language: English
  • Type: Conference paper
  • Identifier: vital:6068 , http://hdl.handle.net/10962/d1004622
  • Description: Teaching accounting to first year university students in higher education institutions is becoming increasingly complex as we deal with increasing class sizes, increasing diversity and a student body which appears to be less inclined to study without external motivating factors, while to be successful in studying accounting requires more than passive learning. Our aim was to make our students active participants in their accounting studies. After studying established research into assessment and approaches to student learning, changes were made to our course to ensure increased and active participation from our students. Critical to this change was guiding students in making the shift from a surface approach to learning, to a deep approach to learning where they would engage with the subject matter in a manner more likely to result in truly understanding the concepts and principles being taught. An important part of implementing these changes was asking our students to evaluate the innovations after they had taken place. Feedback received from our students resulted in the use of a new and unplanned innovation in the form of the setting of regular mini-tests. This was arguably the most successful of all the interventions introduced during the year and resulted in our journey being more exciting and less predictable than expected.
  • Full Text:
  • Date Issued: 2008

Using inetvis to evaluate snort and bro scan detection on a network telescope

  • Authors: Irwin, Barry V W , van Riel, J P
  • Date: 2008
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/429981 , vital:72656 , https://doi.org/10.1007/978-3-540-78243-8_17
  • Description: This paper presents an investigative analysis of net-work scans and scan detection algorithms. Visualisa-tion is employed to review network telescope traffic and identify incidents of scan activity. Some of the identified phenomena appear to be novel forms of host discovery. Scan detection algorithms used by the Snort and Bro intrusion detection systems are cri-tiqued by comparing the visualised scans with alert output. Where human assessment disagrees with the alert output, explanations are sought by analysing the detection algorithms. The Snort and Bro algorithms are based on counting unique connection attempts to destination addresses and ports. For Snort, notable false positive and false negative cases result due to a grossly oversimplified method of counting unique destination addresses and ports.
  • Full Text:
  • Date Issued: 2008

Utility of the cognitive assessment system (CAS) to predict reading proficiency in grade 1

  • Authors: Hüttenrauch, Maria Eleonore
  • Date: 2008
  • Subjects: Das-Naglieri Cognitive Assessment System , Intelligence tests for preliterates , Cognition in children , Reading disability
  • Language: English
  • Type: Thesis , Doctoral , DPhil
  • Identifier: vital:9839 , http://hdl.handle.net/10948/965 , Das-Naglieri Cognitive Assessment System , Intelligence tests for preliterates , Cognition in children , Reading disability
  • Description: Reading disability, as the most commonly diagnosed learning disability, continues to pose a tenacious problem to teachers, practitioners and researchers. In an effort to understand the causes of reading disability, voluminous research has been undertaken over the past decades to pinpoint its causes or developmental stumbling blocks. One approach, the Planning, Attention, Simultaneous, and Successive processing (PASS) model, combines neuropsychological theory with elements from cognitive psychology. Based on this model, the Cognitive Assessment System (CAS), as well as methods of intervention for reading disability were developed. Although many studies have been conducted that investigated reading disability in terms of PASS cognitive processes, the final version of the CAS and its predictive utility with respect to reading disability has not been explored to date. The present study aimed to investigate the utility of the CAS, administered at the beginning of grade 1, to predict reading proficiency at the end of grade 1. The sample was comprised of 119 “average” (i.e., belonging to the general population) grade 1 students from schools of the Calgary Board of Education (CBE). The Basic Battery of the CAS was administered to the children in the sample at the beginning of grade 1, as well as four reading subtests of the Woodcock-Johnson Tests of Achievement – Third Edition (WJ-III ACH) at the end of grade 1. The WJ-III ACH yielded a cluster score for basic reading and one for reading comprehension. Correlational and regression analyses were used to address the first aim of this study, namely to explore the relationship between students’ scores on the CAS and their later reading proficiency. To this end, the children’s CAS Full Scale scores and WJ-III ACH cluster scores were subjected to a hierarchical regression analysis, whereby age, gender, and - xviii - SES were kept constant by entering them first in the equation. Next, the relationship between students’ PASS scale scores and the CAS subtest scores respectively and scores on the WJ-III ACH Basic Reading and Reading Comprehension Cluster scores was explored by means of stepwise regression analysis. To improve on the generalizability of results, the regression analyses were conducted on a randomly drawn analysis sample consisting of 80% of the sample, and cross-validated on the remaining 20% of the sample. The second aim of the present study was to ascertain whether clusters could be identified on the basis of CAS performance as well as levels of reading proficiency. To this end, the children’s CAS FS scores, PASS scale scores, and CAS subtest scores were subjected to cluster analyses. The investigation of aim 1 yielded some encouraging results, in that it was found that, together with the covariates: • The CAS FS emerged as a moderately strong predictor of both basic reading and reading comprehension; • Successive processing, in particular the Word Series subtest, significantly predicted basic reading skills; • Successive and simultaneous processing, particularly the Nonverbal Matrices and Sentence Repetition subtests, were significant predictors of reading comprehension; The second aim, which explored the relationship between patterns of CAS cognitive processes and their relationship with reading proficiency, yielded: • Two clusters with distinctly different PASS scale scores and with significant differences between their levels of reading proficiency. Higher PASS scales scores, particularly on the Attention and Planning scales, were associated with higher reading proficiency scores. • Four clusters with distinctly different CAS subtest scores that were also associated with distinctly different levels of reading performance. Good - xix - reading proficiency was associated with good CAS performance, whereas weaker reading proficiency was linked to weaker CAS performance. Biographical variables, such as age and SES were found to be related to performance on the CAS and reading proficiency, while gender did not emerge as an important predictor variable. The present study demonstrated the usefulness of the CAS, particularly its Successive and Simultaneous scales, as potential early predictor of reading disability. An exploration of the relationship between patterns of CAS cognitive processes and later reading proficiency also yielded encouraging and interesting results.
  • Full Text:
  • Date Issued: 2008
  • Disclaimer
  • Privacy
  • Copyright
  • Contact