The South African community pharmacist and Type 2 Diabetes Mellitus a pharmaceutical care intervention
- Authors: Hill, Peter William
- Date: 2009
- Subjects: Pharmacist and patient -- South Africa , Pharmaceutical services -- Patients , Pharmaceutical services -- South Africa , Pharmacists -- South Africa , Diabetes -- Treatment -- South Africa , Community health services -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3760 , http://hdl.handle.net/10962/d1003238 , Pharmacist and patient -- South Africa , Pharmaceutical services -- Patients , Pharmaceutical services -- South Africa , Pharmacists -- South Africa , Diabetes -- Treatment -- South Africa , Community health services -- South Africa
- Description: Type 2 diabetes mellitus is a chronic disease of pandemic magnitude, increasingly contributing to the disease burden of countries in the developing world, largely because of the effects of unhealthy lifestyles fuelled by unbridled urbanisation. In certain settings, patients with diabetes are more likely to have a healthcare encounter with a pharmacist than with any other healthcare provider. The overall aim of the study was to investigate the potential of South African community pharmacists to positively influence patient adherence and metabolic control in Type 2 diabetes. The designated primary endpoint was glycated haemoglobin, with the intermediate health outcomes of blood lipids, serum creatinine, blood pressure and body mass index serving as secondary endpoints. Community pharmacists and their associated Type 2 diabetes patients were recruited from areas throughout South Africa using the communication media of various nonstatutory pharmacy organisations. Although 156 pharmacists initially indicated interest in participating in the study, only 28 pharmacists and 153 patients were enrolled prior to baseline data collection. Of these, 16 pharmacists and 57 patients participated in the study for the full twelve months. Baseline clinical and psychosocial data were collected, after which pharmacists and their patients were randomised, nine pharmacists and 34 patients to the intervention group and 8 pharmacists and 27 patients to the control group. The sample size calculation revealed that each group required the participation of a minimum of 35 patients. Control pharmacists were requested to offer standard pharmaceutical care, while the intervention pharmacists were provided with a scope of practice diabetes care plan to guide the diabetes care they were to provide. Data were again collected 12-months postbaseline. At baseline, proportionally more intervention patients (82.4%) than control patients (59.3%) were using only oral anti-diabetes agents (i.e. not in combination with insulin), while insulin usage, either alone or in combination with oral agents was conversely greater in the control group (40.7%) than in the intervention group (17.6%) (Chi-squared test, p=0.013). Approximately half of the patients (53.8% control and 47.1% intervention) reported having their HbA1c levels measured in terms of accepted guidelines. There was no significant difference in HbA1c between the groups at the end of the study (Independent t-test, p=0.514). In the control group, the mean HbA1c increased from 7.3±1.2% to 7.6±1.5%, while for the intervention patients the variable remained almost constant (8.2±2.0% at baseline and 8.2±1.8% at post-baseline). Similarly, there were no significant differences between the groups with regard to any of the designated secondary clinical endpoints. Adherence to medication and self-management recommendations was similarly good for both groups. There were no significant differences between the two groups for any of the other psychosocial variables measured. In conclusion, intervention pharmacists were not able to significantly influence glycaemic control or therapeutic adherence compared to the control pharmacists.
- Full Text:
- Date Issued: 2009
The invasion of pteronia incana (blue bush) along a range of gradients in the Eastern Cape Province : it's spectral chacteristics and implications for soil moisture
- Authors: Odindi, John Odhiambo
- Date: 2009
- Subjects: Invasive plants -- South Africa -- Eastern Cape , Alien plants -- South Africa -- Eastern Cape , Soil moisture -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10650 , http://hdl.handle.net/10948/1052 , Invasive plants -- South Africa -- Eastern Cape , Alien plants -- South Africa -- Eastern Cape , Soil moisture -- South Africa -- Eastern Cape
- Description: Extensive areas of the Eastern Cape Province have been invaded by Pteronia incana (Blue bush), a non-palatable patchy invader shrub that is associated with soil degradation. This study sought to establish the relationship between the invasion and a range of eco-physical and land use gradients. The impact of the invader on soil moisture flux was investigated by comparing soil moisture variations under grass, bare and P. incana invaded surfaces. Field based and laboratory spectroscopy was used to validate P. incana spectral characteristics identified from multi-temporal High Resolution Imagery (HRI). A belt transect was surveyed to gain an understanding of the occurrence of the invasion across land use, isohyetic, geologic, vegetation, pedologic and altitudinal gradients. Soil moisture sensors were calibrated and installed under the respective surfaces in order to determine soil moisture trends over a period of six months. To classify the surfaces using HRI, the pixel and sub-pixel based Perpendicular Vegetation Index (PVI) and Spectral Mixture Analysis (SMA) respectively were used. There was no clear trend established between the underlying geology and P. incana invasion. Land disturbance in general was strongly associated with the invasion, as the endemic zone for the invasion mainly comprised abandoned cultivated and overgrazed land. Isohyetic gradients emerged as the major limiting factor of the invasion; a distinct zone below 619mm of mean annual rainfall was identified as the apparent boundary for the invasion. Low organic matter content identified under invaded areas was attributed to the patchy nature of the invader, leading to loss of the top soil in the bare inter-patch areas. The area covered by grass had consistently higher moisture values than P. incana and bare surfaces. The difference in post-rainfall moisture retention between grass and P. incana surfaces was significant up to about six days, after which a near parallel trend was noticed towards the ensuing rainfall episode. Whereas a higher amount of moisture was recorded on grass, the surface experienced moisture loss faster than the invaded and bare surfaces after each rainfall episode. ii There was consistency in multi-temporal Digital Number (DN) values for the surfaces investigated. The typically low P. incana reflectance in the Near Infrared band, identified from the multi-temporal HRI was validated by field and laboratory spectroscopy. The PVI showed clear spectral separability between all the land surfaces in the respective multi-temporal HRI. The consistence of the PVI with the unmixed surface image fractions from the SMA illustrates that using HRI, the effectiveness of the PVI is not impeded by the mixed pixel problem. Results of the laboratory spectroscopy that validated HRI analyses showed that P. incana’s typically low reflectance is a function of its leaf canopy, as higher proportions of leaves gave a higher reflectance. Future research directions could focus on comparisons between P. incana and typical green vegetation internal leaf structures as potential causes of spectral differences. Collection of spectra for P incana and other invader vegetation types, some of which have similar characteristics, with a view to assembling a spectral library for delineating invaded environments using imagery, is another research direction.
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- Date Issued: 2009
The impact of HIV and AIDS on household food security and food acquisition strategies in South Africa
- Authors: Kaschula, S A H
- Date: 2009
- Subjects: Food security -- South Africa Food supply -- South Africa AIDS (Disease) -- Social aspects -- South Africa HIV infections -- Social aspects -- South Africa Chronically ill -- Economic conditions -- South Africa Chronically ill -- Social conditions -- South Africa Food -- Social aspects -- South Africa Food -- Economic aspects -- South Africa Rural development -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4754 , http://hdl.handle.net/10962/d1007137
- Description: How should the impact of HIV and AIDS on rural livelihoods be factored into efforts to monitor and stabilise household food security? With both HIV and AIDS and food security at the top of the global development agenda, this is a question posed by many scholars, practitioners, donor agencies and government departments. However, while there is an excess of discourse outlining the theoretical bases for how HIV and AIDS can, and is, radically transforming household food acquisition; there is a lack of empirical evidence from the South African context that demonstrates if, and how, HIV and AIDS changes household-level strategies of food acquisition and intake. This thesis explores the association of household-level mortality, chronic illness and additional child-dependent fostering with household experience of food security and food acquisition strategies, in three rural villages in the Eastern Cape and KwaZulu-Natal Provinces of South Africa. Qualitative and quantitative methods of data-collection were applied to 307 households in the three sites. For twelve months, both HIV and AIDS-afflicted and non-afflicted households were repeatedly visited at 3-month intervals, in order to be assessed for levels of food security, dietary intake and method of food procurement (purchased, cultivated, wild or donated). Overall, HIV and AIDS-afflicted households showed a significantly higher experience of food insecurity, probably attributable to shortages in food quantity. Dietary composition and overall diversity, however, was not significantly different. Although households with chronic illness and recent mortality showed a heightened investment in cultivation sources, the success of these strategies were to a great extent mediated by household income, and the level of medical treatment received by those who were chronically ill. Chronic illness was also associated with more donations, but these required considerable investments in social capital networks. Finally, use of wild leafy vegetables was not associated with household HIV and AIDS status, despite the financial, nutritional and labour-saving properties of these foods. Overall, the study suggests that there was little evidence of long-term planning and strategy in household food security responses. There was no evidence for shifts to labour-saving crops or foods and, in some instances, child labour was being used to ameliorate prime-adult labour deficits. Moreover, given that the vast majority (89.2%) of food groups were sourced through purchase, it is questionable whether investing in diverse food acquisition strategies would be advisable. Unless supported by medical treatment and steady earned household income, policies to promote intensified household agricultural subsistence production in the wake of HIV and AIDS are unlikely to provide households with anything more than short-term safety-nets, rather than long-term, sustainable food security solutions.
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- Date Issued: 2009
The ecophysiology of Gelidium Pristoides (Turner) Kuetzing : towards commercial cultivation
- Authors: Steyn, Paul-Pierre
- Date: 2009
- Subjects: Marine algae -- South Africa , Marine algae -- Ecophysiology , Red algae -- South Africa , Gelidium -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10617 , http://hdl.handle.net/10948/1117 , Marine algae -- South Africa , Marine algae -- Ecophysiology , Red algae -- South Africa , Gelidium -- South Africa
- Description: The ecophysiology of the red alga Gelidium pristoides (Turner) Kuetzing was investigated in an effort to establish a technique for commercial cultivation. The seaweed is of commercial importance in South Africa where it is harvested from the intertidal zone rocky shores along the coast. It is dried and exported abroad for the extraction of agar. Yields and quality could be improved by cultivation in commercial systems. However, attempts at growing the seaweed in experimental systems have all ended in failure. This study aimed to describe the conditions in which the seaweed grows naturally; and investigate its physiological response to selected physical conditions in the laboratory in order to determine suitable conditions for mariculture. Ecological studies showed that G. pristoides grew above the spring low tide water level. The upper limit of the seaweed’s vertical distribution range, as well as its abundance, was largely dependent on wave exposure. The zone normally inhabited by G. pristoides was dominated by coralline turf in sheltered areas, while the abundance of G. pristoides increased towards more exposed rocky shore sites. The seaweed occurred among species such as Pattelid limpets and barnacles, but was usually the dominant macroalga in this zone, with coralline turf and encrusting algae being the only others. Physical conditions in the part of the intertidal zone inhabited by G. pristoides were highly variable. During low tide temperatures could vary by as much as 10°C within the three hours between tidal inundation of the seaweed population, while salinity varied by up to 9 ppt, and light intensity by as much as 800 μmol m-2 s-1. During these exposure periods the seaweed suffered up to 20% moisture loss. Laboratory experiments on the seaweed’s response to these conditions indicated that it was well adapted to such fluctuations. It had a broad salinity (20 and 40 ppt), and temperature tolerance range (18 to 24°C), with an o ptimum of temperature of 21°C for photosynthesis, while there was no difference in the photosynthetic rate of the alga within the 20 to 40 ppt salinity range. The alga had a low saturating irradiance (ca. 45 – 80 μmol m-2 s-1) equipping it well for photosynthesis in turbulent environments, with high light attenuation, but poorly to unattenuated light conditions. Exposure resulted in an initial increase in photosynthetic rate followed by a gradual decrease thereafter. pH drift experiments showed that low seawater pH, and associated increased carbon dioxide availability, resulted in an increase in photosynthetic rate. This response suggests that the seaweed has a high affinity for carbon dioxide, while the reduction in photosynthetic rate in response to bicarbonate use inhibition indicates that it also has the capacity for bicarbonate use. The high affinity of Gelidium pristoides for carbon dioxide as an inorganic carbon source appears to be the primary reason for the low abundance of the alga on sheltered rocky shore areas, and also explains the failure of the alga to grow in tank or open-water mariculture systems. Exposed rocky shores have experience heavy wave action, and the resultant aeration and mixing of nearshore waters increases the availability of carbon dioxide, which is considered a limiting resource. The absence of such mixing and aeration at sheltered site makes this less suitable habitat for G. pristoides. Periodic exposure also makes high levels of atmospheric carbon dioxide available from which the seaweed benefits. The traditional mariculture systems in which attempts have been made to cultivate the seaweed failed to satisfy either of the above conditions.
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- Date Issued: 2009
The development and evaluation of gaze selection techniques
- Authors: Van Tonder, Martin Stephen
- Date: 2009
- Subjects: Human-computer interaction , User interfaces (Computer systems) , Gaze
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10469 , http://hdl.handle.net/10948/882 , Human-computer interaction , User interfaces (Computer systems) , Gaze
- Description: Eye gaze interaction enables users to interact with computers using their eyes. A wide variety of eye gaze interaction techniques have been developed to support this type of interaction. Gaze selection techniques, a class of eye gaze interaction techniques which support target selection, are the subject of this research. Researchers developing these techniques face a number of challenges. The most significant challenge is the limited accuracy of eye tracking equipment (due to the properties of the human eye). The design of gaze selection techniques is dominated by this constraint. Despite decades of research, existing techniques are still significantly less accurate than the mouse. A recently developed technique, EyePoint, represents the state of the art in gaze selection techniques. EyePoint combines gaze input with keyboard input. Evaluation results for this technique are encouraging, but accuracy is still a concern. Early trigger errors, resulting from users triggering a selection before looking at the intended target, were found to be the most commonly occurring errors for this technique. The primary goal of this research was to improve the usability of gaze selection techniques. In order to achieve this goal, novel gaze selection techniques were developed. New techniques were developed by combining elements of existing techniques in novel ways. Seven novel gaze selection techniques were developed. Three of these techniques were selected for evaluation. A software framework was developed for implementing and evaluating gaze selection techniques. This framework was used to implement the gaze selection techniques developed during this research. Implementing and evaluating all of the techniques using a common framework ensured consistency when comparing the techniques. The novel techniques which were developed were evaluated against EyePoint and the mouse using the framework. The three novel techniques evaluated were named TargetPoint, StaggerPoint and ScanPoint. TargetPoint combines motor space expansion with a visual feedback highlight whereas the StaggerPoint and TargetPoint designs explore novel approaches to target selection disambiguation. A usability evaluation of the three novel techniques alongside EyePoint and the mouse revealed some interesting trends. TargetPoint was found to be more usable and accurate than EyePoint. This novel technique also proved more popular with test participants. One aspect of TargetPoint which proved particularly popular was the visual feedback highlight, a feature which was found to be a more effective method of combating early trigger errors than existing approaches. StaggerPoint was more efficient than EyePoint, but was less effective and satisfying. ScanPoint was the least popular technique. The benefits of providing a visual feedback highlight and test participants' positive views thereof contradict views expressed in existing research regarding the usability of visual feedback. These results have implications for the design of future gaze selection techniques. A set of design principles was developed for designing new gaze selection techniques. The designers of gaze selection techniques can benefit from these design principles by applying them to their techniques
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- Date Issued: 2009
The development and evaluation of a programme to promote sensitive pscyhotherapeutic practice with gay men and lesbians
- Authors: Coetzee, Catherine Ann
- Date: 2009
- Subjects: Psychotherapy -- Practice -- South Africa Psychoanalysis and homosexuality -- South Africa Homosexuality -- Social aspects -- South Africa Homosexuality -- Psychological aspects -- South Africa Psychotherapy -- Moral and ethical aspects -- South Africa Psychologists -- Training of -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2952 , http://hdl.handle.net/10962/d1002461
- Description: Clinical psychology’s relevance and future viability depend on its ability to render services that are relevant and sensitive to multicultural and minority issues. Lesbian, gay, bisexual and transgendered people are one such group that professional psychology – both in South Africa and abroad - has identified as having unique treatment needs for which psychologists require specialised knowledge and skills in order to render appropriate treatment. Competence to treat non-heterosexual patients has been framed in terms of a gay affirmative paradigm which has as its basic tenet the recognition that same-gender orientation is not pathological but rather a healthy alternative to heterosexuality. From this perspective being “gay friendly” or “gay accepting” is not enough. To implement a gay affirmative approach in practice, practitioners must have resolved their possible prejudice and heterosexist bias and have the requisite knowledge of concerns unique to lesbian, gay, and bisexual (LGB) individuals to be able to apply their skills in a culturally sensitive manner. Although more American post-graduate psychology programmes are addressing sexual diversity, their failure to produce psychologists who feel competent to treat lesbian/gay or bisexual individuals has highlighted the need to develop effective training strategies based on empirical nvestigation. The dearth of comparable data about local South African psychology training prompted this inquiry which had four broad aims namely, (i) to establish to what extent trainees’ prior training had equipped them with the knowledge, awareness, and skills to approach their work with non-heterosexual patients in a gay affirmative manner, and (ii) to implement and (iii) to evaluate to what extent a brief structured training programme is effective in engaging the trainees; in increasing knowledge, in raising awareness, and in changing specific attitudes and imparting specific skills required for treating lesbian and gay patients.; and (iv) what, if any, recommendations should be made for the future with respect to training of sychologists in this area? The field of sexual orientation research has been expanded to include issues pertaining to bisexual, transgendered and intersexed people, but serious time constraints meant that issues pertaining to these groups could not be addressed in depth. Although the exclusion of these groups is problematic and may be seen as reinforcing their invisibility, it was decided to focus primarily on gay and lesbian issues s an introduction to same-sex orientation. It is envisaged that bisexual and transgender issues would be dealt with in depth in more advanced training. Nine trainee psychologists employed at hospitals in the greater Cape Town area volunteered to participate in the programme which comprised a series of two-hour experiential workshops offered once a week over six weeks. The study employed both quantitative and qualitative data analysis methods. The first stage entailed gathering information to better understand trainees’ existing level of competence. Individual interviews were conducted prior to the course to obtain data about their attitudes and perceptions regarding the need for such specialised training, and how qualified they considered themselves to be to treat LGB patients, and their experience in this regard. For the purpose of the over-all analysis information was also gathered about pertinent personal and social characteristics of the trainees, as well as their contact with lesbian/gay persons. In addition, an attitude survey and the Lesbian, Gay, and Bisexual Counselling Self-efficacy Scale (LGB-CSI) were administered to obtain benchmarks against which change could be measured. The second stage involved the implementation of the educational programme and gathering information about trainees’ responses to its various components. This stage concentrated on discovering how individual trainees reacted to material on lesbian, gay, and bisexual issues and how they used the programme to improve their self-awareness and skills. The results indicate that local psychology training might not address same-gender orientation adequately, thus reinforcing trainees’ belief that sexual orientation is irrelevant, and that their generalist training equips them to work with gay/lesbian/bisexual patients. While the training strengthened existing positive attitudes, it was less effective in changing blatant antigay prejudice. However, both quantitative and qualitative data suggest that the programme increased individuals’ awareness and insight into their previously unrecognised heterosexist biases and created greater understanding of the effects of stigmatisation on sexual minority individuals. In addition, the training increased trainee’s sense of competence to provide affirmative treatment as evidenced by the significant differences between the pre- and post-training mean scores on the Relationship, Knowledge, and Advocacy Scales and between the mid- and post-training means scores on the Assessment and Awareness Scales of the LGB-CSI. Despite the limited generalisability of these findings on account of possible sampling bias, the need and value of such training was confirmed by trainees’ recommendation that this programme should be a mandatory offering in the first year of clinical psychology training.
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- Date Issued: 2009
The coordination chemistry of Rhenium(V) with multidentate no-donor ligands
- Authors: Abrahams, Abubak'r
- Date: 2009
- Subjects: Rhenium , Ligands
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10370 , http://hdl.handle.net/10948/912 , Rhenium , Ligands
- Description: The neutral distorted octahedral complexes [ReOCl(L)] {H2L = N,N-bis(2- hydroxybenzyl)-2-(2-aminoethyl)dimethylamine (H2had), N,N-bis(2-hydroxybenzyl) aminomethylpyridine (H2hap); N,N-bis(2-hydroxybenzyl)-2-(2-aminoethyl)pyridine (H2hae)} were prepared by the reaction of trans-[ReOCl3(PPh3)2] with a twofold molar excess of H2L in ethanol. The X-ray structure determinations of [ReOCl(had)] and [ReOCl(hap)] were performed, and in both complexes the chloride is coordinated trans to the tripodal tertiary amino nitrogen, with a phenolate oxygen trans to the oxo oxygen. Treatment of trans-[ReO2(py)4]I with two equivalents and one equivalent each of H2had in acetone afforded the iodide salts of the oxypyridinium-ammonium zwitterions N1-(2-hydroxybenzyl)-N2,N2- dimethyl-N1-((2-oxypyridinium)-1-methyl)ethane-1,2-diamine [Hhpd]+ and N2,N2- dimethyl-N1-bis((2-oxypyridinium)-1-methyl)ethane-1,2-diamine [dod]+ respectively. In [Hhpd]I, one of the 2-hydroxyphenyl groups of H2had is substituted by an oxypyridinium group, and in [dod]I, both 2-hydroxyphenyl groups are converted. The X-ray crystal structure determination of the starting material H2had, [Hhpd]I and [dod]I reveals trigonal pyramidal geometries around the central amino nitrogen. The complex salt [ReO(bsa)]PF6 (H2bsa=bis(N-methylsalicylicylideneiminopropyl) amine) was prepared from the reaction of cis-[ReO2I(PPh3)2] with H2bsa in toluene. The dianionic pentadentate ligand bsa is coordinated to the ReO3+ moiety via one secondary amino and two imino nitrogens, and two anionic phenolate oxygens. The complex was characterized by spectroscopy and analytical data, and the structure has been determined by single-crystal X-ray diffraction analysis. The complex exhibits a distorted octahedral geometry around the central rhenium(V) ion, with the basal plane being defined by a phenolate oxygen, two imino nitrogens and the secondary amino. ix A. Abrahams Nelson Mandela Metropolitan University The reaction of a two-fold molar excess of the potentially NN-donor ligand 2,2’- dipyridylamine (dpa) with trans-[ReO(OEt)Cl2(PPh3)2] in ethanol led to the isolation of [ReOCl2(OEt)(dpa)]. The X-ray crystal structure shows that the NN-chelated dpa is coordinated in the equatorial plane cis to the oxo and ethoxo groups, which are in trans positions relative to each other. The treatment of trans- [ReOCl3(PPh3)2] with a tenfold molar excess of dpa in ethanol at the refluxing temperature yielded the trans-dioxo complex [ReO2(dpa)2]Cl, but with a twofold molar excess only (μ-O)[{ReOCl2(dpa)}2] was isolated. Repeating the latter reaction with (n-Bu4N)[ReOCl4] as starting material in ethanol at room temperature a dark green product, also with the formulation (μ-O)[{ReOCl2(dpa)}2], was isolated. The reaction of equimolar quantities of bis(pyridin-2-yl)methyl)amine (HBPA) with (n-Bu4N)[ReOCl4] in acetone at room temperature led to the isolation of the sixcoordinate rhenium(V) complex [ReOCl(H2O)(BPA)]Cl. IR, NMR and X-ray crystallographic results indicate that BPA is coordinated as a tridentate uninegative chelate, with deprotonation of the amine nitrogen. The water molecule is coordinated trans to the oxo group, with the Re=O and Re-OH2 bond distances equal to 1.663(9) and 2.21(1) Å respectively. Complexes of the general formula [ReOX2{(C5H4N)CH(O)CH2(C5H4N)}] (X = Cl, I) were prepared by the reactions of trans-[ReOCl3(PPh3)2] and trans- [ReOI2(OEt)(PPh3)2] with cis-1,2-di-(2-pyridyl)ethylene (DPE) in ethanol and benzene in air. Experimental evidence shows that the coordinated DPE ligand has undergone addition of water at the ethylenic carbons, and that the (C5H4N)CH(O)CH2(C5H4N) moiety acts as a uninegative tridentate NON-donor ligand. The X-ray crystal structures of both complexes show a distorted octahedral geometry around the rhenium(V) centre. The treatment of trans-[ReOCl3(PPh3)2] with H2dbd in a 2:1 molar ratio in acetonitrile led to the isolation of the ligand-bridged dimer (μ-dbd)[ReOCl2(PPh3)]2. The X-ray crystal structure of the complex reveals a dinuclear structure in which two rhenium(V) ions are bridged by the dbd ligand. Each rhenium ion is in a x A. Abrahams Nelson Mandela Metropolitan University distorted octahedral geometry. The basal plane is defined by a phosphorus atom of the PPh3 group, two chlorides cis to each other, and a pyridyl nitrogen atom of dbd. The oxo group and alcoholate oxygen of dbd lie in trans axial positions. The complexes cis-[ReOX2(msa)(PPh3)] (X = Cl, Br, I) were prepared from trans- [ReOCl3(PPh3)2], trans-[ReOBr3(PPh3)2] or trans-[ReOI2(OEt)(PPh3)2] with 2-(1- iminoethyl)phenol (Hmsa) in acetonitrile. An X-ray crystallographic study shows that the bonding distances and angles in the comlexes are nearly identical, and that the two halides in each complex are coordinated cis to each other in the equatorial plane cis to the oxo group. The oxo-bridged dinuclear rhenium(V) complex [(μ-O){ReOCl(amp)}2] was prepared by the reaction of trans-[ReOCl3(PPh3)2] and 6-amino-3-methyl-1-phenyl- 4-azahept-2-ene-1-one (Hamp) in acetone. The characterization of the complex by elemental analysis, infrared and 1H NMR spectroscopy and X-ray crystallography shows that amp is coordinated as a monoanionic NNO-donor chelate as an amino-amido ketone. However, the reaction of the similar ligand 7- amino-4,7-dimethyl-5-aza-3-octen-2-one (Hada) with [Re(CO)5Br] produced the product fac-[Re(CO)3Br(Hada)], with Hada coordinated as a neutral NN-donor amino-imino-ketone.
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- Date Issued: 2009
Teacher educators' interpretation and practice of learner-centred pedagogy : a case study
- Authors: Nyambe, Kamwi John
- Date: 2013-07-16
- Subjects: Bernstein, Basil B Education -- Philosophy Education (Higher) -- Namibia Teacher educators -- Namibia -- Case studies Universities and colleges -- Namibia -- Case studies Teachers -- Traning of -- Namibia -- Case studies Teachers -- In-service training -- Namibia Student-centered learning -- Namibia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1954 , http://hdl.handle.net/10962/d1008260
- Description: The objective of this study was to understand how teacher educators in a Namibian college of education interpret and practice the learner-centred pedagogy underpinning the Basic Education Teachers Diploma (BETD) program. In order to achieve this objective, a case study approach was adopted, qualitative-interpretive in orientation and drawing upon interviews, naturalistic non-participant observation and document analysis. Bernstein's theory of pedagogy - in particular his notion ofrecontextualization - offered ideas and concepts that were used to generate and analyse data. The data indicated that, at the level of description, teacher educators interpreted leamercentred pedagogy as a pedagogic practice based on weak rules of regulative discourse, or a weak power relation between themselves and their student teachers. The weakening of the rules of regulative discourse and the waning of educator authority were indicated in the interview narratives, which evoked a pedagogic context characterized by a repositioning of the student teacher from the margins to the centre of the classroom, where he or she enjoyed a more active and visible pedagogic position. Contrary to the dis empowering dynamic within classroom practice under the apartheid dispensation, the repositioning of the student teacher suggested a shift of power towards him or her. Similarly, the identification of the teacher educator as afacilitator, which featured prominently in the interview narratives, further suggested a weakening or diminishing of the pedagogic authority of the teacher educator. With regard to rules pertaining to the instructional discourse, the data revealed an interpretation of leamer-centred pedagogy as a pedagogic practice based on strong framing over the selection of discourses, weak framing over pacing, and strong framing over sequencing and criteria for evaluation. When correlated with the interview data, the data generated through lesson observation and teacher educator prepared documents such as lesson plans revealed a disjuncture between teacher educators' ideas about leamer-centred pedagogy and their practice of it. Contrary to the interviews, lesson observation data revealed that teacher educators implemented leamer-centred pedagogy as a pedagogic practice based on strong internal framing over rules of the regulative discourse. Data further indicated strong internal framing over the selection, sequencing, pacing and evaluation. The study concluded that while some teacher educators could produce an accurate interpretation oflearner-centred pedagogy at the level of description, most of them did not do so at the level of practice. Findings revealed structural and personal-psychological factors that constrained teacher educators' recontextualization of the new pedagogy. A narrow understanding of leamercentred pedagogy that concentrated only on changing teacher educators' pedagogical approaches from teacher-centred to learner-centred, while ignoring structural and systematic factors, tended to dominate not only the interview narratives but also official texts. Learner-centred pedagogy was understood as a matter of changing from teachercentredness to leamer-centredness while frame factors, for instance regarding the selection, pacing or sequencing of discourses, still followed the traditional approach. The study recommends the adoption of a systematic and deliberate approach to address the multiplicity of factors involved in enabling teacher educators to interpret and implement leamer-centred pedagogy at the micro-level of their classrooms. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
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Student's van Hiele levels of geometric thought and conception in plane geometry: a collective case study of Nigeria and South Africa
- Authors: Atebe, Humphrey Uyouyo
- Date: 2009
- Subjects: Geometry -- Study and teaching (Secondary) -- Nigeria -- Case studies Geometry -- Study and teaching (Secondary) -- South Africa -- Case studies Mathematics -- Study and teaching (Secondary) -- Nigeria -- Case studies Mathematics -- Study and teaching (Secondary) -- South Africa -- Case studies
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1777 , http://hdl.handle.net/10962/d1003662
- Description: This study is inspired by and utilises the van Hiele theory of geometric thought levels, currently acclaimed as one of the best frameworks for studying teaching and learning processes in geometry. The study aims both to explore and explicate the van Hiele levels of geometric thinking of a selected group of grade 10, 11 and 12 learners in Nigerian and South African schools. The study further aims to provide a rich and indepth description of the geometry instructional practices that possibly contributed to the levels of geometric conceptualisation exhibited by this cohort of high school learners. This collective case study, presented in two volumes, is oriented within an interpretive research paradigm and characterised by both qualitative and quantitative methods. The sample for the study comprised a total of 144 mathematics learners and 6 mathematics teachers from Nigeria and South Africa. They were selected using both purposive and stratified sampling techniques. In using the van Hiele model to interrogate both learners’ levels of geometric conceptualisation and teaching methods in geometry classrooms, the study employs a qualitative and qunatitative approach to the data-collection process, involving the use of questionnaires (in the form of various pen-and-paper tests, hands-on activity-based tests), interviews and classroom videos. Although the data analysis was done largely through descriptive statistics, the whole process inevitably incorporated elements of inferential statistics (e.g. ANOVA and Tukey HSD post-hoc test) in the quest for indepth analysis and deeper interpretation of the data. Learners were assigned to various van Hiele levels, mainly according to Usiskin’s (1982) forced van Hiele level determination scheme. The whole process of analysing the classroom videos involved a consultative panel of 4 observers and 3 critical readers, using the checklist of van Hiele phase descriptors to guide the analysis process. Concerning learners’ levels of geometric conceptualisation, the results from this study reveal that the most of the learners were not yet ready for the formal deductive study of school geometry, as only 2% and 3% of them were respectively at van Hiele levels 3 and 4, while 47%, 22% and 24% were at levels 0, 1 and 2, respectively. More learners from the Nigerian subsample (53%) were at van Hiele level 0 than learners from the South African subsample (41%) at this level. No learner from the Nigerian subsample was at van Hiele level 4, while 6% of the South African learners were at level 4. In general, learners from the Nigerian subsample had a poorer knowledge of school geometry than their peers from the South African subsample, as learners from the latter subsample obtained significantly higher mean scores in the van Hiele Geometry Test (VHGT) and each of the other tests used in this study. Results relating to gender differences in performance generally favour the male learners in this study. For each of the participating schools, learners’ van Hiele levels (as determined by their scores on the VHGT) strongly correlate with their performance in geometry content tests and mathematics generally. For each of the Nigerian and South African subsamples, for n ≤ 2, learners at van Hiele level n obtained higher means on nearly all the tests administered in this study than their peers at level n–1. This finding provides support for the hierarchical property of the van Hiele levels.
- Full Text:
- Date Issued: 2009
Social policy, welfare in urban services in South Africa : a case study of free basic water, indigency and citizenship in Eastwood, Pietermaritzburg, KwaZulu-Natal (2005-2007)
- Authors: Smith, Julie
- Date: 2009
- Subjects: Municipal water supply -- South Africa -- Pietermaritzburg , Water-supply -- Social aspects -- South Africa -- Pietermaritzburg , Poor -- South Africa -- Pietermaritzburg , Water-supply -- Economic aspects -- South Africa , South Africa -- Social policy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6060 , http://hdl.handle.net/10962/d1015231
- Description: This is an in-depth case study of urban water services to poor households and their interactions with local state power in the community of Eastwood, Pietermaritzburg, in the province of KwaZulu-Natal, South Africa, for the period 2005-2007. It draws especially on the experiences of poor women, exploring the conceptions and implications of the movement of municipal services into the realm of welfare-based urban service concessions. It interrogates what value municipal services, framed in the language and form of welfare but within a commodification milieu and in the context of shifting citizen-state relations offer the state apparatus and how such free basic service offerings are experienced by poor households at the level of domestic, social and economic functioning. The study adopts a fluid mixed-methodological approach to optimise exploration and interpretation. It argues that the interface of state service delivery and citizens is fraught with contradictions: core to this is the nature of state ' help.' Free basic water encompassed in the social wage did not improve the lives of poor households; instead it eroded original water access. Free basic water stole women's time spent on domestic activities; compromised appropriate water requirements, exacerbated service affordability problems and negatively affected household functioning. Poor households experienced the government's policy of free basic services as containment and punishment for being poor. The Indigent Policy activated the state's surveillance, disciplinary and control apparatus. In the absence of effective national regulation over municipalities and with financial shortfalls, street-level bureaucrats manipulated social policies to further municipal cost recovery goals and subjugate poor households. Social control and cheap governance were in symmetry. Citizens, desperate for relief, approached the state. Poor households were pushed into downgraded service packages or mercilessly pursued by municipally outsourced private debt collectors and disconnection companies. Municipalities competing for investments brought about by favourable credit ratings abandoned the humanity of their citizens. Such re-prioritisation of values had profound implications for governance and public trust. Citizens were jettisoned to the outskirts of municipal governance, resulting in a distinct confusion and anger towards the local state - and with it, major uncertainties regarding future stability, redistribution and equity.
- Full Text:
- Date Issued: 2009
Rhenium (I) and (V) complexes with potentially mulidentate ligands containing the Amino group
- Authors: Booysen, Irvin Noel
- Date: 2009
- Subjects: Rhenium , Ligands
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10386 , http://hdl.handle.net/10948/1270 , Rhenium , Ligands
- Description: The complex trans-[Re(dab)Cl3(PPh3)2] (H2dab = 1,2-diaminobenzene) was prepared from the reaction of trans-[ReOCl3(PPh3)2] with H2dab in ethanol. The ligand dab is coordinated to the rhenium(V) centre through a dianionic imido nitrogen only in a distorted octahedral coordination geometry around the metal ion. The complex trans- [Re(ada)Cl3(PPh3)2] (H2ada = 2-aminodiphenylamine) was prepared from the reaction of trans-[ReOCl3(PPh3)2] with H2ada in acetonitrile. The ligand ada is coordinated to the rhenium(V) centre through a dianionic imido nitrogen only, in a distorted octahedral coordination geometry around the metal ion. The ‘2 + 1’ complex fac- [Re(CO)3(Hamp)(amp)] (Hamp = 2-aminophenol) was isolated from the reaction of a two molar ratio of Hamp with [Re(CO)5Br] in toluene. The reaction of a 1:1 molar ratio of [Re(CO)5Br] and H2ada led to the isolation of the Re(I) complex, fac- [Re(CO)3Br(H2ada)]. The reaction of equimolar quantities of cis-[ReO2I(PPh3)2] with 5,6-diamino-1,3- dimethyluracil (H2ddd) in acetonitrile led to the formation of [Re(ddd)(Hddd)I(PPh3)2](ReO4). The X-ray crystal structure shows that the ligand ddd is coordinated monodentately through the doubly deprotonated amino nitrogen and is therefore present as an imide. The chelate Hddd is coordinated bidentately via the neutral amino nitrogen, which is coordinated trans to the imido nitrogen, and the singly deprotonated amido nitrogen, trans to the iodide. The reaction of trans-[ReOCl3(PPh3)2] with N-(2-aminobenzylidene)-5-amino-1,3-dimethyl uracil (H3dua) in ethanol gave a mixed crystal which contains both the neutral oxorhenium(V) complex [ReOCl(Hdua)] and the imido rhenium(V) [Re(dua)Cl2(PPh3)] in an equimolar ratio in the asymmetric unit. The reaction of equimolar quantities of [NH4(ReO4)] with H2ddd in methanol under reflux led to the isolation of [C12H12N6O4] as only product. The [ReO4]- anion is therefore instrumental in the formation of [C12H12N6O4], and since the product contains no rhenium in any oxidation state, the conclusion is that [ReO4]- catalyses the oxidative deamination Abstract I.N. Booysen Nelson Mandela Metropolitan University vii of H2ddd. The X-ray crystal structure consists of two centrosymmetric, tricyclic rings, comprising a central pyrazine ring and two terminal pyrimidine rings. The reaction of 2-(2-aminophenyl)benzothiazole (Habt) with [Re(CO)5Br] led to the isolation of the rhenium(I) complex fac-[Re(Habt)(CO)3Br]. With trans-[ReOCl3(PPh3)2], the ligand Habt decomposed to form the oxofree rhenium(V) complex [Re(itp)2Cl(PPh3)] (itp = 2-amidophenylthiolate). From the reaction of trans-[ReOBr3(PPh3)2] with 2-(2- hydroxyphenyl)benzothiazole (Hhpd) the complex [ReVOBr2(hpd)(PPh3)] was obtained. The reaction of a twofold molar excess of H2apb (2-(2-aminophenyl)-1-benzimidazole) with trans-[ReO2(py)4]Cl in ethanol gave the green product of formulation [ReO(Hapb)(apb)] in good yield. The rhenium atom lies in a distorted trigonalbipyramidal environment. The two imidazole N(2) atoms lie in the apical positions trans to each other, with the oxo-oxygen and two amido N(1) atoms in the trigonal plane. A new nitrosylrhenium(II) complex salt, [Re(NO)BrL2(PPh3)2](ReO4) (H2L2 = 2-amino-5- (triphenylphosphino)phenol), is the first example of a complex containing the triphenylphosphonium-amidophenolate ligand L2, formed by the nucleophilic attack of a PPh3 on a coordinated amidophenolate ring. The complex salt trans-[Re(mps)Cl(PPh3)2](ReO4) (H3mps = N-(2-amino-3- methylphenyl)salicylideneimine) was prepared by the reaction of trans-[ReOCl3(PPh3)2] with a twofold molar excess of H3mps. The X-ray crystal structure shows that the trianionic ligand mps acts as a tridentate chelate via the doubly deprotonated amino nitrogen (an imide), the neutral imino nitrogen and the deprotonated phenolic oxygen. The six-coordinated complex cis-[Re(mps)Cl2(PPh3)2] was prepared by the reaction of trans-[ReOCl3(PPh3)2] with a twofold molar excess of H3mps in benzene. The X-ray crystal structure show that the mps ligand coordinates as a tridentate chelate via the doubly deprotonated 2-amino nitrogen, the neutral imino nitrogen and the phenolate oxygen. The imide and phenolate oxygen coordinate trans to each other in a distorted octahedral geometry, around the rhenium(V) centre, with the two chlorides in cis positions. A new oxofree rhenium(V) complex salt, [Re(bbd)2](ReO4) ( H2bbd = N-(2- Abstract I.N. Booysen Nelson Mandela Metropolitan University viii aminobenzylidene)benzene-1,2-diamine), has been synthesized and the chelates bbd are coordinated as dianionic tridentate N,N,N-donor diamidoimines. The rhenium(V) ion is centered in a distorted trigonal prism. The rhenium(I) compound fac-[Re(CO)3(daa)].Hpab.H2O (Hpab = N1,N2-(1,2- phenylene)bis(2-aminobenzamide); Hdaa = 2-amino-N-(2-aminophenyl)benzamide) was synthesized from the reaction of [Re(CO)5Br] with a two equivalents of Hpab in toluene. The monoanionic tridentate ligand daa was formed by the rhenium-mediated cleavage of an amido N-C bond of the potentially tetradentate ligand Hpab. Daa is coordinated as a diaminoamide via three nitrogen-donor atoms. The reaction of a twofold molar excess of H2amben (H2amben = N1,N2-bis(2-aminobenzylidene)ethane-1,2-diamine) with trans- [ReOBr3(PPh3)2] gave the oxorhenium(V) cationic complex [ReO(amben)]X (X = Br-, PF6 -). The Re(V) oxo-bridged compound, {μ-O}[ReO(omben)]2.H2O (H2omben = N1,N2- bis(2-hydroxybenzylidene)ethane-1,2-diamine) was isolated from the reaction of a 2:1 molar ratio of H2omben and trans-[ReO2(py)4]Cl in methanol. The seven-coordinate rhenium(III) complex cation [ReIII(dhp)(PPh3)2]+ was isolated as the [ReO4]- salt from the reaction of cis-[ReVO2I(PPh3)2] with 2,6-bis(2- hydroxyphenyliminomethyl)pyridine (H2dhp) in ethanol. In the complex fac- [Re(CO)3(H2dhp)Br], prepared from [Re(CO)5Br] and H2dhp in toluene, the H2dhp ligand acts as a neutral bidentate N,N-donor chelate. An equimolar ratio reaction of 2-aminobenzaldehyde and 2-(2-aminophenyl)-1- benzimidazole in methanol led to 2-(5,6-dihydrobenzimidazolo[1,2-c]-quinazolin-6- yl)aniline. In an attempt to explore the template formation of this class of ligand with rhenium, the reaction of salicylaldehyde and 2-(2-aminophenyl)-1-benzimidazole in ethanol which was followed by the addition of trans-[ReOBr3(PPh3)2] led to the formation of the salt, 6-(2-hydroxyphenyl)-5,6-dihydrobenzimidazolo[1,2-c]quinazolin- 12-ium bromide. The compound 6-(2-methylthiophenyl)-5,6-dihydrobenzimidazolo[1,2- c]quinazolin-12-ium was synthesized via the reaction of 2-aminobenzaldehyde and 2- methylthiobenzaldehyde in methanol.
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- Date Issued: 2009
Regulating franchise operations in South Africa : a study of the existing legal framework with suggestions for reform.
- Authors: Woker, Tanya Ann
- Date: 2009
- Subjects: Franchise Association of Southern Africa , Franchises (Retail trade) -- Law and legislation -- South Africa , South Africa. Dept. of Trade and Industry , Common law -- South Africa , Commercial law -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3721 , http://hdl.handle.net/10962/d1015719
- Description: This thesis analyses the existing legal framework that applies to franchising in South Africa today. The study begins with an examination of the history and nature of the franchise contract, focusing particularly on the nature of the franchise relationship. This study is undertaken in order to substantiate the argument that franchising is a unique method of doing business. There is a need therefore to recognise that the franchise contract is a special contract in its own right, just like contracts of sale, lease, insurance and suretyship. The study then goes on to examine the problems which are experienced in the sector, as well as the law which must provide solutions to these problems. The research will show that in a modern commercial world the existing legal framework, especially the common law, cannot adequately deal with many of these problems. The complex relationship between franchising and competition law is also explored. A common thread that emerges from franchise disputes is the lack of protection afforded to the interests of franchisees. Franchisees tend to be at the mercy of economically stronger franchisors, hence the belief that there is a need for a stronger regulatory framework. The study then shifts to proposals for reform. In 2000 the Department of Trade and Industry (DTI) established the Franchise Steering Committee in conjunction with the Franchise Association of South Africa (FASA) to review the regulatory environment. This Committee drafted franchise legislation which aimed to bring the regulation of the sector under the control of the DTI. This legislation has not been implemented and the DTI has changed its strategy. Instead of dealing with franchising independently, franchising will fall within the scope of consumer protection legislation. Both the consumer protection legislation and the legislation proposed by the Franchise Steering Committee are thoroughly examined and explained. Shortcomings in the proposals are highlighted and an alternative approach is recommended. It is proposed that franchise-specific legislation should be introduced but that this legislation should establish a system of co-regulation between the government and the franchise sector.
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- Date Issued: 2009
Racism and law : implementing the right to equality in selected South African equality courts
- Authors: Krüger, Rósaan
- Date: 2009
- Subjects: South Africa Promotion of Equality and Prevention of Unfair Discrimination Act, 2000 , Equality -- South Africa , Discrimination -- Law and legislation -- South Africa , Racism -- Law and legislation -- South Africa , Apartheid -- Law and legislation -- South Africa , Constitutional law -- South Africa , South Africa -- Politics and government -- 1994-
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3677 , http://hdl.handle.net/10962/d1003192 , South Africa Promotion of Equality and Prevention of Unfair Discrimination Act, 2000 , Equality -- South Africa , Discrimination -- Law and legislation -- South Africa , Racism -- Law and legislation -- South Africa , Apartheid -- Law and legislation -- South Africa , Constitutional law -- South Africa , South Africa -- Politics and government -- 1994-
- Description: Racism has informed South African society since colonial times. Racist beliefs found expression in the laws of colonial and apartheid South Africa and shaped both state and society. The constitutional state that South Africa has become since 1994, is based on the values of ‘human dignity’, ‘the achievement of equality’ and ‘nonracialism’, among others. Law formed the basis of the racist state prior to 1994, and now law has a fundamental role to play in the transformation of the state and society in an egalitarian direction by addressing socio-economic inequalities on the one hand, and by changing patterns of behaviour based on racist beliefs forged in the past, on the other. This thesis examines one of the legal instruments that is intended to contribute to transformation in the latter sense, namely the Promotion of Equality and Prevention of Unfair Discrimination Act 4 of 2000 (the Equality Act), with specific reference to the issue of racism. The provisions of this Act and the framework for its operation against the background of South Africa’s racist past, and within the broader framework of international and constitutional law, are examined. These two legal frameworks are analysed for the purpose of determining the standards set by international and constitutional law regarding racial equality in order to determine whether the Equality Act measures up. This thesis also incorporates an analysis of the practical application of the provisions of the Equality Act to complaints of racism in selected equality courts. The theoretical analysis of the Act’s provisions and their application in the equality courts point to various problematic formulations and obstacles which negatively affect the application of the provisions and thus hamper social change. The thesis concludes with recommendations for refining the Act’s provisions and its application.
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- Date Issued: 2009
Polarization mode dispersion emulation and the impact of high first-order PMD segments in optical telecommunication systems
- Authors: Musara, Vitalis
- Date: 2009
- Subjects: Optical communications , Fiber optics , Polarization (Light)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10519 , http://hdl.handle.net/10948/1138 , Optical communications , Fiber optics , Polarization (Light)
- Description: In this study, focus is centred on the measurement and emulation of first-order (FO-) and second-order (SO-) polarization mode dispersion (PMD). PMD has deleterious effects on the performance of high speed optical transmission network systems from 10 Gb/s and above. The first step was characterising deployed fibres for PMD and monitoring the state of polarization (SOP) light experiences as it propagates through the fibre. The PMD and SOP changes in deployed fibres were stochastic due to varying intrinsic and extrinsic perturbation changes. To fully understand the PMD phenomenon in terms of measurement accuracy, its complex behaviour, its implications, mitigation and compensation, PMD emulation is crucial. This thesis presents emulator designs which fall into different emulator categories. The key to these designs were the PMD equations and background on the PMD phenomenon. The cross product from the concatenation equation was applied in order to determine the coupling angle β (between 0o and 180o) that results in the SO-PMD of the emulator designs to be either adjustable or fixed. The digital delay line (DDL) or single polarization maintaining fibre (PMF) section was used to give a certain amount of FO-PMD but negligible SO-PMD. PMF sections (birefringent sections) were concatenated together to ensure FO- and SO-PMD coexist, emulating deployed fibres. FO- and SO-PMD can be controlled by altering mode coupling (coupling angles) and birefringence distribution. Emulators with PMD statistics approaching the theoretical distributions had high random coupling and several numbers of randomly distributed PMF sections. In addition, the lengths of their PMF sections lie within 20% standard deviation of the mean emulator length. Those emulators with PMD statistics that did not approach the theoretical distributions had limited numbers of randomly distributed PMF sections and mode coupling. Results also show that even when an emulator has high random mode coupling and several numbers of randomly distributed PMFs, its PMD statistics deviates away from expected theoretical distributions in the presence of polarization dependent loss (PDL). The emulators showed that the background autocorrelation function (BACF) approaches zero with increasing number of randomly mode coupled fibre sections. A zero BACF signifies that an emulator has large numbers of randomly distributed PMF sections and its presence means the opposite. The availability of SO-PMD in the emulators made the autocorrelation function (ACF) x asymmetric. In the absence of SO-PMD the ACF for a PMD emulator is symmetric. SO-PMD has no effect on the BACF. Polarization-optical time domain reflectometry (P-OTDR) measurements have shown that certain fibre sections along fibre link lengths have higher FO-PMD (HiFO-PMD) than other sections. This study investigates the impact of a HiFO-PMD section on the overall FO- and SO-PMD, the output state of polarization (SOP) and system performance on deployed fibres (through emulation). Results show that when the wavelength-independent FO-PMD vector of the HiFO-PMD section is greater than the FO-PMD contributions from the rest of the fibre link, the mean FO-PMD of the entire link is biased towards that of the HiFO-PMD section and the SO-PMD increases (β ≠ 0o or 180o) or remains fixed (β = 0o or 180o) depending on the coupling angle β between the HiFO-PMD section and the rest of the fibre link. In addition, the FO-PMD statistics deviates away from the theoretical Maxwellian distribution. However, experimental results show that the HiFO-PMD section has negligible influence on the SOPMD statistical distribution. An increase in the amount of FO-PMD on a HiFO-PMD section reduces the output SOP spread to a given minimum, in this study the minimum was reached when the HiFO-PMD ≥ 35 ps. However, the outcome of the output SOP spread depends on the location of the HiFO-PMD section along the fibre link length. It was found that when the HiFO-PMD section introduces SO-PMD, the bit error rate (BER) is much higher compared to when it does not introduce SO-PMD.
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- Date Issued: 2009
Photophysical and photochemical behaviour of metallophthalocyanines effect of nanoparticles and molecules of biological importance
- Authors: Idowu, Mopelola Abidemi
- Date: 2009
- Subjects: Electrochemistry Phthalocyanines Nanoparticles
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4329 , http://hdl.handle.net/10962/d1004990
- Description: Syntheses, spectral, photophysical and photochemical studies of some neutral, anionic and cationic metallophthalocyanine derivatives are presented. The effects of central metal ions, solvents, aggregation, surfactant, nanoparticles and bovine serum albumin on the photophysical and photochemical behaviour are investigated. Mercaptocarboxylic acid stabilized CdTe quantum dots (QDs) were used as energy donors to anionic water-soluble MPcs through Förster resonance energy transfer (FRET). Energy transfer (ET) from the QDs to the MPcs occurred upon photoexcitation of the QDs. An enhancement in efficiency of ET with the nature of the cappings on the QDs was observed with few occurrences of a non-Förster type ET. QDs were found to improve the photophysicochemical behaviour of the MPcs, with the possibility of indirect production of singlet oxygen (Φ[subscript Δ]) via FRET mechanism. Interaction of the QDs with cationic water-souble MPcs produced ion-pair complexes resulting in aggregates due to strong electronic coupling. The stoichiometry of the reaction and association constants are evaluated by the continuous variation method. Improved photophysicochemical behaviour with no spectral alterations was observed in MPcs in the presence of magnetic fluid. Complexes showed high triplet quantum yields with corresponding long lifetimes and high photostability. Elucidation of the results of the interaction of bovine serum albumin (BSA) with MPcs or QDs is presented. Increased efficiency of Φ[subscript Δ] generation of MPcs in the presence of BSA coupled with large binding constants, suggesting strong interaction of the MPcs with BSA was observed. Enhanced emission intensity of QDs when linked to or in a mixture with BSA due to radiationless recombination at the surface vacancies was also observed. The study revealed positive deviation from Stern-Volmer relationship suggesting the occurrence of static and dynamic mechanisms of quenching together. Fluorescence quenching of the MPcs by benzoquinone, analysed by Stern-Volmer relationship is also presented; the results were employed in determining fluorescence lifetimes of the complexes. Photoelectrochemical characteristics of MPc-sensitized electrodeposited ZnO thin films were studied; ZnOCPc / ZnO films have been improved to an incident photon-to-currentconversion (IPCE) value of 31.1 % with an absorbed photon-to-current conversion (APCE) of 59.6 %. The best obtained so far with phthalocyanine-type sensitizers on nanocrystalline ZnO films. Fluorescent-magnetic nanocomposite with excellent photophysical properties which can be exploited for combined photodynamic and hyperthermia therapies is also presented.
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- Date Issued: 2009
Patterns and determinants of species richness in mesic temparate grasslands of South Africa
- Authors: Hoare, David Barry
- Date: 2009
- Subjects: Grassland ecology -- South Africa -- Eastern Cape , Plant diversity -- South Africa -- Eastern Cape , Vegetation and climate
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10613 , http://hdl.handle.net/10948/1275 , Grassland ecology -- South Africa -- Eastern Cape , Plant diversity -- South Africa -- Eastern Cape , Vegetation and climate
- Description: The aim of this study is to gain a predictive understanding of the patterns and determinants of plant biodiversity in temperate, mesic grasslands of South Africa with a primary focus on the geographical area of the Eastern Cape. From a review of the literature on hypotheses explaining diversity (Chapter 2) it was possible to formulate a number of hypotheses that could be tested to explain species richness patterns in Eastern Cape grasslands. This thesis is organised so that each main chapter deals with a specific body of theory concerning the explanation of diversity patterns. A detailed description of the study area is provided (Chapter 3), including environmental variation and a description of major vegetation patterns. A summary is provided of grassland plant community patterns, as determined by phytosociological studies in the study area. A multivariate analysis of environmental variables was undertaken to determine which variables contributed the most towards explaining environmental variation in the study area and to determine whether any variables co-vary, a possible problem for any multivariate analysis in later chapters. Altitude produced one of the strongest gradients in the study area. There were a number of variables that were correlated with altitude, most notably temperature. Rainfall co-varied partially with altitude, but there was also a strong rainfall gradient perpendicular to the altitude gradient. A description of species richness, diversity and evenness patterns at the plot scale within different grassland plant communities of the Eastern Cape is provided in Chapter 4. To determine whether the environment acts differently on different growth forms, the contribution to species richness by different major growth forms is analysed. Furthermore, since the majority of literature attempts to explain diversity in terms of environmental factors, it was necessary to analyse the relationship between species richness and various environmental variables. The results indicate that there is high variation in species richness both within and among grassland communities. Forbs make the most significant contribution to overall species richness per 100 m2, followed by grasses. Variance in richness of all species together is not significantly related to environmental variables in mesic grasslands, but is significantly related to environmental variables in semi-arid grasslands. The result of greatest interest from this chapter is the fact that richness amongst different life-forms in the same place is explained by different environmental factors, indicating that the environmental factors that affect coexistence of species have a different effect on different life-forms. A classification of all the species of the dataset into plant functional types using a multivariate approach based on functional traits was conducted (Chapter 5). The grass species were classified into 16 functional types and the forbs into 14 functional types. The functional type classification provided the opportunity for undertaking analyses to develop an understanding of 8 the contribution by niche differentiation towards promoting species richness (Chapter 6). The results provide evidence of niche differentiation in the grasslands of the study area and also that niche differentiation promotes species richness in the grasslands of the study area. It was found that higher rainfall grasslands are less structured by niche differentiation than semi-arid grasslands. A regional / historical analysis is undertaken (Chapter 7) to investigate the relationship between the regional species pool and local richness, and the relationship between local richness and phytochorological diversity. Regional richness appears to have little effect in promoting local richness in grassland plant communities of the study area except at sites where there is high local richness. This provides an indication that regional richness only promotes local richness in the absence of local limiting factors. Phytochorological diversity promotes local richness, but mostly through diversity amongst species with narrow distribution ranges. Some theories ascertain that seasonal uncertainty may provide opportunities to species that would otherwise be outcompeted and thereby promote local richness. The degree to which seasonal uncertainty and seasonality promote local richness in the Eastern Cape grasslands was therefore investigated (Chapter 8). A weak relationship exists between these variables and local species richness in grassland communities of the study area, indicating that they do not promote niche differentiation to a significant degree in the study area. It is clear that in the grasslands of the Eastern Cape, environmental limiting factors are more important in semi-arid grasslands and species interactions are more important in mesic grasslands for structuring plant communities (Chapter 9, Discussion). Regional processes do not appear to be important in structuring local communities, but the analysis undertaken in this study shows that they may be significant when factors operating at the other two levels are overcome (species interactions and environmental limiting factors.
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- Date Issued: 2009
New platinum coordination compounds : their synthesis, characterization and anticancer application
- Authors: Oosthuizen, Lukas Marthinus
- Date: 2009
- Subjects: Platinum compounds , Antineoplastic agents
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10430 , http://hdl.handle.net/10948/d1018795
- Description: The aim of this thesis was to investigate the properties of novel platinum compounds with possible potential as anticancer agents, and to determine how their behaviour could lead to a better understanding of the chemistry involved. The final criteria were improvement of their anticancer behaviour. Since many questions are still unanswered as to the role of sulfur in anticancer action, studies were undertaken to synthesize novel platinum(II) complexes having non-leaving groups consisting of a combination of an aromatic nitrogen and thioetherial sulfur capable of forming a five membered ring upon coordination. The structural unit was 1-methyl-2-methylthioalkyl/aryl. Numerous complexes formed by these ligands each having chloro, bromo, iodo and oxalato leaving groups were then fully characterized. The results obtained by the various synthetic methods were compared and explained in terms of the chemistry involved. The role of the sulfur donor was indicated in both the halo- and oxalato-complexes and proved to be strongly influenced by the nature of the leaving groups. Their differences are reflected in their anticancer behaviour. The study was extended to mononitroplatinum(IV) complexes, in view of the kinetically stable platinum(IV) compounds and advantages related to this. A specific mononitroplatinum(IV) complex which proved to have good anticancer and STAT 3 properties could according to the literature not be synthesized successfully in a good yield and a high degree of purity. The results of extensive studies showed that the main problem centred around the simultaneous reactions in equilibrium during the synthesis. A number of these species formed as a result of side reactions could be identified and their close separation factors indicated chromatographically. The mechanism of these reactions and the unstable intermediate species involved could be rationalized and compared to analogues in the literature. All the complexes studied were characterized by spectral and thermal methods both in solution as well as the solid state. Their anticancer behaviour towards three anticancer cell lines (Hela, MCF 7, Ht 29) were determined and acted as a guide towards possible structural modifications for their improved capability. Three crystal structures of platinum(II) complexes were determined. The extent of the ionization of the platinum(II) complexes as well the redox potentials (Pt(II) / Pt(IV)) of the platinum(IV) complexes were particularly important factors pertaining to their anticancer action.
- Full Text:
- Date Issued: 2009
Myth, Music & Modernism: the Wagnerian dimension in Virginia Woolf's Mrs Dalloway and the waves and James Joyce’s Finnegans Wake
- Authors: McGregor, Jamie Alexander
- Date: 2009
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/77069 , vital:30662
- Description: The study of Wagner's influence on the modernist novel is an established field with clear room for further contributions. Very little of the criticism undertaken to date takes full cognizance of the philosophical content of Wagner's dramas: a revolutionary form of romanticism that calls into question the very nature of the world, its most radical component being Schopenhauer's version of transcendental idealism. The compatibility of this doctrine with Wagner's earlier work, with its already marked privileging of myth over history, enabled his later dramas, consciously influenced by Schopenhauer, to crown a body of work greater than the sum of its parts. In works by Virginia Woolf and James Joyce, the "translation" of Wagnerian ideas into novelistic form demonstrates how they might be applied in "real life". In Mrs Dalloway, the figure of Septimus can be read as partly modelled on Wagner's heroes Siegfried and Tristan, two outstanding examples of the opposing heroic types found throughout his oeuvre, whose contrasting attributes are fused in Septimus's bipolar personality. The Wagnerian pattern also throws light on Septimus's transcendental "relationship" with a woman he does not even know, and on the implied noumenal identity of seemingly isolated individuals. In The Waves, the allusions to both Parsifal and the Ring need to be reconsidered in light of the fact that these works' heroes are all but identical (a fact overlooked in previous criticism); as Wagner's solar hero par excellence, Siegfried is central to the novel's cyclical symbolism. The Waves also revisits the question of identity but in a more cosmic context – the metaphysical unity of everything. In Finnegans Wake, the symbolism of the cosmic cycle is again related to the Ring, as are Wagner's two heroic types to the Shem / Shaun opposition (the Joyce / Woolf parallels here have also been overlooked in criticism to date). All three texts reveal a fascination with the two contrasting faces of a Wagnerian hero who embodies the dual nature of reality, mirroring in himself the eternal rise and fall of world history and, beyond them, the timeless stasis of myth.
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- Date Issued: 2009
Mathematical requirements for first-year BCOM students at NMMU
- Authors: Walton, Marguerite
- Date: 2009
- Subjects: Business mathematics -- South Africa , Mathematics -- Study and teaching (Higher) -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10502 , http://hdl.handle.net/10948/886 , Business mathematics -- South Africa , Mathematics -- Study and teaching (Higher) -- South Africa
- Description: These studies have focused on identifying the mathematical requirements of first-year BCom students at Nelson Mandela Metropolitan University. The research methodology used in this quantitative study was to make use of interviewing, questionnaire investigation, and document analysis in the form of textbook, test and examination analysis. These methods provided data that fitted into a grounded theory approach. The study concluded by identifying the list of mathematical topics required for the first year of the core subjects in the BCom degree programme. In addition, the study found that learners who study Mathematics in the National Senior Certificate should be able to cope with the mathematical content included in their BCom degree programme, while learners studying Mathematical Literacy would probably need support in some of the areas of mathematics, especially algebra, in order to cope with the mathematical content included in their BCom degree programme. It makes a valuable contribution towards elucidating the mathematical requirements needed to improve the chances of successful BCom degree programme studies at South African universities. It also draws the contours for starting to design an efficient support course for future “at-risk” students who enter higher education studies.
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- Date Issued: 2009
Learning, governance and livelihoods : toward adaptive co-management under resource poor conditions in South Africa
- Authors: Cundill, Georgina
- Date: 2009
- Subjects: Natural resources -- Co-management -- South Africa Rural poor -- South Africa Rural development -- South Africa Households -- Economic aspects -- South Africa Sustainable development -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4747 , http://hdl.handle.net/10962/d1006961
- Description: Through collaborative monitoring and case study comparison, this thesis explores conceptual and methodological approaches to monitoring transitions toward adaptive co-management. In so doing, a number of knowledge gaps are addressed. Firstly, conceptual and methodological frameworks are developed for monitoring transitions toward adaptive co-management. Secondly, a conceptual and practical approach to monitoring the processes of collaboration and learning is developed and tested. Thirdly, a conceptual and practical approach to monitoring the governance outcomes of adaptive co-management is developed and tested. Fourthly, a conceptual and practical approach to monitoring the livelihood outcomes of adaptive co-management is developed and tested. Based on the outcomes from these four components of the study, this thesis explores the ways in which transitions toward adaptive co-management might be initiated under the resource poor conditions that characterise South Africa's communal areas. The four case studies explored in the study are described as 'resource poor' in terms of institutional capacity, ecosystem productivity and social vulnerability. From a resilience perspective these case studies can be described as being in the re-organisation phase of the adaptive cycle following multiple disturbances over time, largely due to South Africa's historical 'separate development' policies. Scholars have suggested that it is in this re-organisation phase that innovation and novelty might occur. The lens of social learning is applied to analyse collaborative processes within these contexts. Results indicate that the institutional innovation necessary for transitions toward adaptive co-management relies on careful facilitation by an 'honest broker'. Equally important is finding a balance between maintaining key individuals and knowledge holders within decision making networks, and preventing rigidity and vulnerability within communities of practice. The results point to an over simplification in the rhetoric that currently surrounds the learning outcomes of multi level networks. The governance outcomes of the initiatives are explored through the lenses of adaptive governance, social capital, adaptive capacity and self-organisation. Results indicate that under resource poor conditions creating the conditions that facilitate self-organisation is the major challenge facing transformations toward adaptive governance. Long term access to reliable information and capacity and financial support for adaptive management are key constraining variables. The livelihood outcomes of the initiatives are analysed through the lens of resilience and diversification. Results suggest that flexibility, rather than livelihood diversity, is the key livelihood strategy employed by households in situations were options are limited. Interventions that enhance opportunities for households to specialise in situ by actively dealing with structural constraints, such as access to markets and credit, is vital to encouraging innovation during transitions toward adaptive co-management. Based on the results from monitoring, this study identifies key focus areas that require a great deal more attention if transitions toward adaptive co-management are to be initiated under resource poor conditions.
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- Date Issued: 2009