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Effects of substituents on the photochemical and photophysical properties of main group metal phthalocyanines

  • Authors: Nyokong, Tebello
  • Date: 2007
  • Language: English
  • Type: Article
  • Identifier: vital:6581 , http://hdl.handle.net/10962/d1004146
  • Description: The review focuses on the photochemical (singlet oxygen and photobleaching quantum yields) and photophysical (triplet quantum yields and lifetimes and fluorescence lifetimes) properties of metallophthalocyanine complexes containing main group metals (Zn, Al, Ge, Si, Sn, Ga and In) and some unmetallated phthalocyanine complexes. Five tables containing photophysical and photochemical data for sulfonated phthalocyanines, tetra-, octa-substituted and unsubstituted phthalocyanines in a variety of solvents, are included in the review.
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  • Date Issued: 2007

Electroanalysis of thiocyanate using a novel glassy carbon electrode modified by aryl radicals and cobalt tetracarboxyphthalocyanine

  • Authors: Matemadombo, Fungisai , Westbroek, Philippe , Nyokong, Tebello
  • Date: 2007
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/268750 , vital:54228 , xlink:href="https://doi.org/10.1016/j.electacta.2007.06.064"
  • Description: Electrochemical grafting of 4-nitrobenzenediazonium tetrafluoroborate onto a glassy carbon electrode (GCE) results in the formation of a nitrophenyl radical, which reacts with the surface to form a covalent bond (grafting) and results in a nitrophenyl modified electrode. The nitro group is electrochemically reduced to a NH2 group. Cobalt tetracarboxyphthalocyanine (CoTCPc) complex is then attached to the NH2 group using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and N-hydroxysuccinimide (NHS) as coupling agents. The new CoTCPc modified electrode was characterized using cyclic voltammetry and then employed for the catalytic oxidation of thiocyanate.
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  • Date Issued: 2007

Electrocatalytic activity of arylthio tetra-substituted oxotitanium (IV) phthalocyanines towards the oxidation of nitrite

  • Authors: Tau, Prudence , Nyokong, Tebello
  • Date: 2007
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/281234 , vital:55704 , xlink:href="https://doi.org/10.1016/j.electacta.2006.12.059"
  • Description: This paper investigates the catalytic activities of arylthio substituted oxotitanium phthalocyanine (OTiPc) complexes that are immobilized on the glassy carbon electrode by electropolymerization, towards the oxidation of nitrite. The complexes are peripherally and non-peripherally substituted with phenylthio and benzylthio groups, namely 1a, 1b, 2a and 2b. All the modified electrodes exhibited improved electrocatalytic oxidation of nitrite than the unmodified electrodes by a two-electron mechanism producing nitrate ions. Catalytic currents are enhanced and nitrite overpotential reduced to ∼0.60 V. Kinetic parameters are determined for all complexes and a mechanism is proposed.
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  • Date Issued: 2007

Electrocatalytic oxidation of chlorophenols by electropolymerised nickel (II) tetrakis benzylmercapto and dodecylmercapto metallophthalocyanines complexes on gold electrodes

  • Authors: Agboola, Bolade , Nyokong, Tebello
  • Date: 2007
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/281247 , vital:55705 , xlink:href="https://doi.org/10.1016/j.electacta.2007.02.017"
  • Description: This work reports on the use of nickel(II) tetrakis benzylmercapto (NiTBMPc) and dodecylmercapto (NiTDMPc) metallophthalocyanine complexes films on gold electrodes for the electrochemical oxidation of 4-chlorophenol (4-CP) and 2,4,5-trichlorophenol (TCP). Both NiTBMPc and NiTDMPc complexes were successfully deposited on gold electrodes by electropolymerisation. The films were electro-transformed in aqueous 0.1 M NaOH solution to the ‘O–Ni–O oxo’ bridged form. For both complexes, films with different thickness were prepared and characterised by electrochemical impedance and UV–vis (on indium tin oxide) spectroscopies and the results showed typical behaviour for modified electrodes with increasing charge transfer resistance values (Rp) with polymer thickness. The poly-Ni(OH)NiPcs showed better catalytic activity than their poly-NiPcs counterparts.
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  • Date Issued: 2007

Electrocatalytic oxidation of nitrite by tetra-substituted oxotitanium (IV) phthalocyanines adsorbed or polymerised on glassy carbon electrode

  • Authors: Tau, Prudence , Nyokong, Tebello
  • Date: 2007
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/268762 , vital:54230 , xlink:href="https://doi.org/10.1016/j.jelechem.2007.07.019"
  • Description: Comparative electrocatalytic oxidation of nitrite by tetra aryloxy-substituted oxotitanium(IV) and tetraamino phthalocyanine complexes is investigated in this work. The aryloxy complexes are substituted at the peripheral (4) and non-peripheral (5) positions with phenoxy (complexes a), 4-tert-butylphenoxy (complexes b), benzyloxy (complexes c) and 4-(benzyloxy)phenoxy (complexes d) groups. The glassy carbon electrode was employed and modified with the tetra aryloxy-substituted titanium phthalocyanine complexes (4 and 5) by adsorption, and with titanium tetraamino phthalocyanine (TiTAPc) by polymerisation. All complexes reduced the overpotential of the nitrite electrooxidation as well as enhanced the catalytic current by a 2 electron process.
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  • Date Issued: 2007

Electrochemical and photophysical characterization of non-peripherally-octaalkyl substituted dichlorotin (IV) phthalocyanine and tetrabenzotriazaporphyrin compounds

  • Authors: Khene, Samson M , Cammidge, Andrew N , Cook, Michael J , Nyokong, Tebello
  • Date: 2007
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/271216 , vital:54522 , xlink:href="https://doi.org/10.1142/S1088424607000886"
  • Description: Three non-peripherally substituted tin(IV) macrocylic compounds, octahexylphthalocyaninato dichlorotin(IV) (3a), octahexyltetrabenzo-5,10,15- triazaporphyrinato dichlorotin(IV) (3b) and octadecylphthalocyaninato dichlorotin(IV) (3c) were synthesized and their photophysical and electrochemical behavior studied. Complex 3b, containing a CH group in place of one of the aza nitrogen atoms of the phthalocyanine core, shows a split Q-band due to its lower symmetry. The triplet state quantum yields were found to be lower than would be expected on the basis of the heavy atom effect of tin as the central metal for phthalocyanine derivatives (3a and 3c). In contrast, 3b shows a triplet quantum yield ΦT = 0.78. The triplet state lifetimes were solvent dependent, and were higher in tetrahydrofuran than in toluene. Cyclic voltammetry and spectroelectrochemistry of the complexes revealed only ring-based redox processes.
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  • Date Issued: 2007

Electrochemical characterisation of tetra- and octa-substituted oxo(phthalocyaninato)titanium(IV) complexes

  • Authors: Tau, Prudence Lerato , Nyokong, Tebello
  • Date: 2007
  • Language: English
  • Type: Article
  • Identifier: vital:6598 , http://hdl.handle.net/10962/d1004347
  • Description: The synthesis and electrochemical characterisation of the following oxotitanium tetra-substituted phthalocyanines are reported: 1,(4)-(tetrabenzyloxyphthalocyaninato)titanium(IV) oxide (5a); 1,(4)- {tetrakis[4-(benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide (5b); 2,(3)- (tetrabenzyloxyphthalocyaninato)titanium(IV) oxide (6a) and 2,(3)-{tetrakis[4- (benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide (6b). The electrochemical characterisation of complexes octa-substituted with 4-(benzyloxy)phenoxy (9b), phenoxy (9c) and tert -butylphenoxy (9d) groups is also reported. The cyclic voltammograms of the complexes exhibit reversible couples I–III and couple IV is quasi-reversible for complexes 5a, 5b, 6a and 6b. The first two reductions are metal-based processes, confirmed by spectroelectrochemistry to be due to Ti IV Pc 2 − /Ti III Pc 2 − and Ti III Pc 2 − /Ti II Pc 2 − redox processes and the last two reductions are ring-based processes due to Ti II Pc 2 − /Ti II Pc 3 − and Ti II Pc 3 − /Ti II Pc 4 − . Chronocoulometry confirmed a one-electron transfer at each reduction step. The electrochemistry of the above complexes is also compared to the previously reported 5c, 5d, 6c and 6d.
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  • Date Issued: 2007

Elephant feeding behaviour and forage offtake implications in the Addo Elephant National Park

  • Authors: Lessing, Joan Susanna
  • Date: 2007
  • Subjects: Elephants -- South Africa -- Addo Elephant National Park , Elephants -- Behavior , Addo Elephant National Park (South Africa) , Mammals -- Behavior
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10712 , http://hdl.handle.net/10948/542 , http://hdl.handle.net/10948/d1012016 , Elephants -- South Africa -- Addo Elephant National Park , Elephants -- Behavior , Addo Elephant National Park (South Africa) , Mammals -- Behavior
  • Description: Elephants, as megaherbivores and keystone species have major impacts, both positive and negative, on ecosystems such as the Subtropical Thicket of the Eastern Cape. The feeding behaviour of elephants was quantified so as to firstly determine the preferred feeding heights of elephants, and secondly to determine if feeding behaviour and impact varies with size and sex. The preferred feeding height was determined with experimental feeding trials. Feeding height, pluck size, foraging rate and the proportion of plant material discarded were used to test for differences between elephants of different sizes and sexes in the Addo Elephant National Park. The influence of plant growth form on sex-specific feeding was also considered. Elephants preferred to feed at the lowest heights. The preferred feeding height was not related to body size. A wide range of feeding heights was recorded including and extending beyond, both the preferred and maximum feeding height of co-existing indigenous browsers. There was no difference in feeding height between the sizes and sexes. In free ranging conditions, all elephants fed at levels above the preferred foraging height when browsing. There was no difference in feeding behaviour between the different sized elephants, or between males and females. Adult elephants however exhibited larger ranges of feeding heights, pluck sizes, foraging rates and intake rates, including the maximum and minimum values. Growth form influenced the feeding of male and female elephants differently. Elephant feeding behaviour appears to limit opportunities for resource partitioning by way of feeding height segregation. Elephants are also capable of dominating the browse resources available to co-existing browsers by removing large amounts of forage at lower heights. The extent of elephant impact seems to be comparable between sizes and sexes, although adults and especially larger males are often able to use foraging opportunities that other elephants can not effectively utilize. Findings suggest that the feeding heights of elephants are determined by forage availability and reflect the diet in terms of browse or grass. The findings can be used, together with browse inventory methods, to determine browse resources available to elephants, and can also be used to develop monitoring tools to assess the impacts of elephants on plants.
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  • Date Issued: 2007

Eluvial chromite resources of the Great Dyke of Zimbabwe

  • Authors: Musa, Caston Tamburayi
  • Date: 2007
  • Subjects: Dikes (Geology) -- Zimbabwe Chromite -- Zimbabwe Geology -- Zimbabwe Olivine Serpentinite Eluvium
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5046 , http://hdl.handle.net/10962/d1007731
  • Description: Apart from the concentrations of chromite in layers within the Great Dyke and other ultramafic complexes, chromite also occurs as interstitial grains throughout the olivine-bearing rock-types. These olivine-bearing rocks include no rites, gabbros, dunites and pyroxenites. Chromite concentration in these rocks varies from 0.48 to 3.09 per cent of the rock, usually in the form of chromite (Ahrens, 1965; Worst, 1960). A small fraction of this chromite settled to form chromitite layers whilst the remainder is retained within the rock mass as finely disseminated chromite and chromite interstitial to olivine. This retained chromite is much finer grained than layer chromite and is the primary source of eluvial chromite (Cotterill, 1981). During weathering of the serpentine rock and transportation by rainwater, the heavier chromite and magnetite grains are re-deposited along watercourses and vleis or valleys as the speed of the water is retarded sufficiently for the heavier particles to settle. The lighter serpentine material is removed and the chromite concentration in the soil is increased, thus resulting in eluvial chromite (Keech et ai, 1961; Worst, 1960; Prendergast, 1978). The concentration of chromite particles in soil can be up to 15 (or more) Cr₂O₃ %, resulting in economic and exploitable deposits, located primarily along the Great Dyke fiacks. A preliminary evaluation of the eluvials indicate that the Great Dyke could be host to up to 10 million tonnes of potential chromite concentrates which could be processed from such eluvial concentrates. These chromite-rich soils can be mined more cheaply than the traditional seams mining and processed into chromite concentrates through simple mechanical processing techniques of spirals, jigs and heavy media separators. The resultant chromite concentrates are of high quality and can be used to manufacture chromite ore briquettes, which are an alternative to lumpy chromite smelter feed. The main challenges to eluvial mining are the inevitable environmental degradation and coming up with methods that could possibly mitigate against such environmental damage. The distribution of these eluvials over vast plains as thin soil horizons, necessitate use of mobile concentrator plants and hence establishment of extensive infrastructure. These challenges, however, are not insurmountable and test mining and previous production runs have proved profitable. The eluvials are also associated with some lateritic nickel concentrations. The nickel occurs in close association with some oxide such as goethite and garnierite and is associated with iron-manganiferous soil pisolites. The analyses of these pisolites indicate high nickel grades of generally above 1.00 %Ni. Such high nickel-content of Great Dyke laterites warrant, further investigations.
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  • Date Issued: 2007

Emotional intelligence and effective team functioning of MBA syndicate groups at the NMMU business school

  • Authors: Doolabh, Chetna Gidhar
  • Date: 2007
  • Subjects: Emotional intelligence , Interpersonal relations , Teams in the workplace , Nelson Mandela Metropolitan University. Business School
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: vital:8747 , http://hdl.handle.net/10948/740 , Emotional intelligence , Interpersonal relations , Teams in the workplace , Nelson Mandela Metropolitan University. Business School
  • Description: A common issue in leadership development is the high flyers who reach a position where their lack of “soft” skills hampers their performance and proves a barrier to their continued progression to higher levels of responsibility (Newell, 2002: 288). Business Schools offering Masters in Business Administration (MBA) programmes assist in developing managers with not just managerial competence but also with “soft” skills. By delivering educated business managers, these managers through their intellectual skills and community sensitive values, will lead future transformational processes. It is useful and interesting to consider how important emotional intelligence is for effective performance at work. A considerable body of research suggests that an employee’s ability to perceive, identify, and manage emotion provides the basis for the kinds of social and emotional competencies that are important for success in almost any position. Furthermore, as the pace of change increases and the world of work make ever-greater demands on an employee’s cognitive, emotional, and physical resources, this particular set of abilities will become increasingly important (Cherniss, 2000). The primary objective of this study is to determine the perceptions of the Masters in Business Administration (MBA), B-Tech in Business Administration (BBA), Advanced Business Programme (ABP) programmes and the Business School Alumni to determine the overall emotional intelligence profile of students as well as the effective team functions of the syndicate groups. Based on the main findings of the survey, it was concluded that emotional intelligence is an important factor for the NMMU Business School, MBA Unit students. The skills attained through the course work will not only improve team effectiveness in the syndicate group functioning but also enhance their performance in the business environment. The MBA team learning experiences enhances workplace learning as the ability to work in a team and ability to think and act independently are highly desired skills and competencies for success in the workplace.
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  • Date Issued: 2007

Enabling and constraining ICT practice in secondary schools: case studies in South Africa

  • Authors: Hodgkinson-Williams, Cheryl , Siebörger, Ingrid , Terzoli, Alfredo
  • Date: 2007
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/428923 , vital:72546 , https://www.inderscienceonline.com/doi/epdf/10.1504/IJKL.2007.015551
  • Description: The use of Information Communication Technology (ICT) in education is being seen as a way of widening access to education, particularly in developing countries. This paper addresses the issue of ICT implemen-tation in secondary schools and focuses specifically on the practices that enable or constrain the successful implementation of ICT for teach-ing and learning activities. It reflects upon the lessons learned from a collective case study undertaken in 12 of the 13 secondary schools in Grahamstown in the Eastern Cape in South Africa. School principals and designated IT teachers were interviewed and on-site infrastructure audits conducted. This paper identifies a number of key enabling and constraining factors surrounding practical issues, including sufficient hardware, appropriate software and affordable connectivity, sufficient technical support and training, policy-related issues such as the role of national, provincial and school policy, the vital contribution of principal leadership and champion teachers as well as ongoing teacher profes-sional development coupled with a willingness to change.
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  • Date Issued: 2007

Endozoochory in the subtropical thicket: comparing effects of species with different digestive systems on seed fate

  • Authors: Davis, Shavaughn
  • Date: 2007
  • Subjects: Seeds -- Dispersal
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10714 , http://hdl.handle.net/10948/494 , http://hdl.handle.net/10948/d1012018 , Seeds -- Dispersal
  • Description: Endozoochory is an important form of seed dispersal and as such plays a fundamental role in plant population and community ecology. This is especially true in the Subtropical Thicket biome where many plant species are adapted for endozoochory. Endozoochorous seed dispersal is carried out by a wide range of thicket fauna, but changes in the faunal assemblage associated with transformed thicket threatens to disrupt the process of endozoochorous seed dispersal and in turn the regeneration dynamics of thicket plants. Outside of conservation areas, indigenous seed dispersers are often replaced by domestic species, such as goats, which are hypothesized to differ in their seed dispersal efficiencies. The dispersal efficiencies of important thicket seed dispersers that occur in transformed and untransformed thicket were therefore investigated. The influence of gut morphologyphysiology on seed gut passage time, seed mortality and germination in animal species representing different digestive models was measured, as well as the role of black-backed jackal in thicket plant seed dispersal. Black-backed jackal were found to disperse the seeds of few thicket plant species and are therefore not considered important thicket seed dispersers under the climatic conditions prevailing during the study. The average gut passage time of seeds was found to differ significantly between birds and mammals, but not between elephants (hindgut fermentor), goats (ruminant) and pigs (omnivore, foregut fermentor) as was expected considering the differences in their digestive morphology. A significantly shorter gut passage of large seeds compared with small seeds was observed in goats, due to the regurgitation of larger seeds. Seed regurgitation in ruminants may prove to be an important factor contributing to their quality as seed dispersers in transformed thicket. The mortality of seeds was significantly higher in goats than in elephants, probably due to the efficient digestion associated with ruminants. The effect of gut passage on seed germination was not consistent and varied between animal species and across different thicket plant species. It was concluded that seed dispersers that occur in transformed and untransformed thicket differ in their seed dispersal efficiency due, in part, to differences in the nature of their digestive tracts. This has important implications for the process of seed dispersal in thicket, and the rehabilitation of degraded thicket vegetation.
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  • Date Issued: 2007

Engaging employees to build a performance culture in Telkom's NCC division

  • Authors: Goliath, Elize
  • Date: 2007
  • Subjects: Performance -- Management , Quality assurance -- Management , Organizational effectiveness , Telkom (Firm : South Africa)
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: vital:8591 , http://hdl.handle.net/10948/1051 , Performance -- Management , Quality assurance -- Management , Organizational effectiveness , Telkom (Firm : South Africa)
  • Description: Operating as a commercial company since October 1991, Telkom has grown into the largest communications services provider in Africa based on operating revenue and assets. The Group, consisting of the fixed-line company Telkom and a 50 per cent shareholding in mobile operator Vodacom. Telkom has changed its vision to the following: “To be a leading customer and employee centric ICT solutions service provider”. The company has been retrenching staff since 1999 and the staff numbers have reduced significantly from approximately 65 000 people to 25 575 people in 2006. The focus has been on increasing shareholder value and the staff feel that their value has not been recognised. The research paper focused on the extent that employees engaged to build a performance culture in Telkom’s NCC division. The following research methodology was followed: - A literature survey to determine factors or behaviours that will enhance employee engagement in building a performance culture and what Telkom NCC can do to build the workplace that will foster higher levels of employee engagement. - A survey was conducted to determine what the engagement levels of employees are at Telkom NCC, what stops the employees from doing their best and what Telkom NCC division can do to show they care and value their staff as according to their employees by means of a questionnaire. - The findings from the literature study and empirical study would be used to determine to what extent are employees engaged to build a performance culture in Telkom’s NCC division. A self administered questionnaire was used to collect the data required for this research. In conclusion it was said that employee engagement is a partnership between the company and the employees where everyone works together to achieve the business objectives of the company and the personal aspirations of employees. The organization has the responsibility to create the conditions for this to happen (Understanding Employee Engagement, 2004: 2). It was recommended that in order for NCC to enhance their employees attitudes toward the promoters’ team especially in terms of pride, strong attachment, feeling part of the family and motivating employees to do well promoters must concentrate on building relationships with their teams and individual members of the team. Employees must also be given decision making power for implementing the idea. NCC should educate their leaders on the value of recognition and the best way to go about it. In order for employees to grow and be promoted into higher positions, NCC must consider that if positions become available that they first be advertised in the NCC division before it be made available to the rest of the company.
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  • Date Issued: 2007

Enhancing phosphorus availability in some phosphate fixing soils of the Transkei region, South Africa using goat manure

  • Authors: Gichangi, Elias Maina
  • Date: 2007
  • Subjects: Phosphorus in agriculture , Soils -- Phosphorus content , Phosphatic fertilizers , Soils -- Phosphorus content -- South Africa -- Transkei
  • Language: English
  • Type: Thesis , Doctoral , PhD (Soil Science)
  • Identifier: vital:11960 , http://hdl.handle.net/10353/80 , Phosphorus in agriculture , Soils -- Phosphorus content , Phosphatic fertilizers , Soils -- Phosphorus content -- South Africa -- Transkei
  • Description: Low availability of soil phosphorus (P) caused by strong sorption of P is a major constraint to agricultural production in most South African soils, particularly those from the high rainfall areas. The aim of this study was therefore to investigate whether combined addition of goat manure with inorganic P fertilizers could enhance P availability in some P fixing soils of the Transkei region, South Africa. The study addressed the following specific objectives (i) to assess P sorption capacities and requirements of selected soils and their relationship with selected soil properties and single point sorption test, (ii) to assess the effects of goat manure and lime addition on P sorption properties of selected P fixing soils (iii) to assess the temporal changes in concentration of inorganic and microbial biomass P fractions following application of inorganic fertilizer P with goat manure in a laboratory incubation experiment, and, (iv) to assess the effects of goat manure application with inorganic phosphate on inorganic and microbial biomass P fractions, P uptake and dry matter yield of maize. Sorption maxima (Smax) of seven soils examined ranged from 192.3 to 909.1 (mg P kg-1) and were highly and positively correlated with sorption affinity constant (r = 0.93, p = 0.01) and organic C (r = 0.71, p = 0.01). The amount of P required for maintaining a soil solution concentration of 0.2 mg P l-1 ranged from 2.1 to 123.5 mg P kg-1 soil. Soils collected from Qweqwe (a Cambisol), Qunu (an Acrisol), Ncihane (a Luvisol) and Bethania (a Ferralsol) had lower external P requirement values and were classified as lower sorbers, whereas soils from Ntlonyana (a Planosol), Chevy Chase (a Ferralsol) and Flagstaff (a Ferralsol) were classified as moderate sorbers. The results suggested that P availability could be compromised in 43 percent iii of the soils studied and that measures to mitigate the adverse effects of P sorption were needed to ensure that P is not a limiting factor to crop production, where such soils are found. Goat manure addition at varying rates (5, 10 and 20 tha-1 dry weight basis) to two of the moderately P fixing soils from Chevy Chase and Flagstaff, reduced P sorption maxima (Smax) compared to the control treatment. Phosphate sorption decreased with increasing amounts of goat manure in both soils but the extent of reduction was greater on Chevy Chase soil than on Flagstaff soil. The relative liming effects of the different rates of goat manure followed the order 20 t GM ha-1 > 10 t GM ha-1 > 5 t GM ha-1. In a separate experiment, addition of inorganic P at varying rates (0, 90, 180, and 360 kg P ha-1) to Flagstaff soil increased labile P fractions (resin P, biomass P and NaHCO3-Pi) and the increases were greater when goat manure was co-applied. The control treatments contained only 17.2 and 27.5 mg P kg-1 of resin extractable P in the un-amended and manure amended treatments, respectively which increased to 118.2 and 122.7 mg P kg-1 on day 28 of incubation. Biomass P concentration was increased from 16.8 to 43.9 mg P kg-1 in P alone treatments but the fraction was greatly enhanced with manure addition, increasing it from 32.6 to 97.7 mg P kg-1. NaOH-Pi was the largest extractable Pi fraction and ranged from 144.3 to 250.6 mg P kg-1 and 107.5 to 213.2 mg P kg-1 in the unamended and manure amended treatments, respectively. Dry matter yield and P uptake by maize grown in the glasshouse were highly and significantly (p = 0.05) correlated with the different P fractions in the soil. The correlations followed the order resin P (r = 0.85) > NaOH-Pi (r = 0.85) > NaHCO3-Pi (r = 0.84) >> biomass P (r = 0.56) for dry matter yield at 6 weeks after planting. At 12 weeks after planting, goat manure had iv highly significant effects on resin P and biomass P but had no effect on NaHCO3-Pi and NaOH–Pi. The combination of biomass P, resin P and NaHCO3-Pi explained 75.8 percent of the variation in dry matter yield of which 63.0 percent of the variation was explained by biomass P alone. The greatest increase in biomass P occurred when added P was co-applied with 5 or 10 tha-1 goat manure. The predictive equation for maize dry matter yield (DM) was: DM (g) = 1.897 biomass P + 0.645 resin P (r = 0.73). Resin P was the fraction that was most depleted due to plant uptake and decreased by 56 to 68 percent between the 6th week and the 12th week of sampling indicating that it played a greater role in supplying plant available P. The results therefore suggested that the use of goat manure may allow resource poor farmers to use lower levels of commercial phosphate fertilizers because of its effect to reduce soil P sorption. In addition, higher increases in biomass P due to manure addition observed at lower rates of added P indicated that goat manure has potential for enhancing bioavailability and fertilizer use efficiency of small inorganic P applications.
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  • Date Issued: 2007

Enlarged arguments in Bantu : evidence from Chichewa

  • Authors: Simango, Silvester Ron
  • Date: 2007
  • Language: English
  • Type: Article
  • Identifier: vital:6140 , http://hdl.handle.net/10962/d1011592
  • Description: This paper re-examines two types of constructions that have featured in the discussion of possessor ascension in Bantu: one type – an applicative construction – is associated with alienable possession, and the other – non-applicative – is associated with inalienable possession. The study shows that the former expresses affectedness, and that the possessor reading arises only by construal; whereas the latter expresses a part–whole relationship. The paper argues that the two constructions differ in more significant ways than has previously been acknowledged; and that their distinct derivations cannot be captured by traditional possessor ascension (PA) analyses. The putative “alienable” possessor constructions belong to the class of (benefactive) applicative constructions and should be analyzed as such. The paper proposes that the so-called “inalienable” possessor constructions can best be accounted for by positing the existence of “enlarged arguments” wherein the possessum functions as a nominal predicate which more narrowly pinpoints the locus of the action described by the verb.
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  • Date Issued: 2007

Environment and sustainability education in a changing South Africa: A critical historical analysis of outline schemes for defining and guiding learning interactions

  • Authors: O'Donoghue, Rob B
  • Date: 2007
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/373634 , vital:66708 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122749"
  • Description: This paper examines how, in response to emerging risk, methodological narratives for conservation (CE), environmental (EE) and now sustainability education (ESD) were constituted in diverse settings within a changing South African state. After documenting an awareness creation perspective underpinning early extension and experiential activities, the study examines shaping social processes and changing outline schemes for defining and guiding planned learning interactions (methodology) within the broadening field into the present day. The critical historical analysis developed in the study reflects a well-documented shift from early topdown (intervention/extension) to more participatory approaches (collaborative engagement/stewardship). A situated process-mapping of changing orientations also reveals characterising methodological features across the contours of an increasingly diverse field of conservation, environment and sustainability education.
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  • Date Issued: 2007

Establishing the benefits of implementing an I.T. project management office in the Nelson Mandela Metropolitan area

  • Authors: Martin, Michael Ronald Charles
  • Date: 2007
  • Subjects: Project management -- South Africa -- Port Elizabeth -- Computer network resources , Information technology -- South Africa -- Port Elizabeth -- Management
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:9266 , http://hdl.handle.net/10948/558 , Project management -- South Africa -- Port Elizabeth -- Computer network resources , Information technology -- South Africa -- Port Elizabeth -- Management
  • Description: The well-known concept of a Project Manager managing an I.T. project in relative isolation is no longer a viable option for organisations that are running numerous projects simultaneously. Due to the enormous costs and risks involved in many of these projects, there needs to be a means to ensure success. This has led to the establishment of the concept of a Project Management Office (PMO). An autonomous business unit that is responsible for managing all projects within an organisation. The need for a Project Management Office (PMO) to effectively manage multiple projects is becoming more and more accepted worldwide. The benefits of a PMO are well documented, but whether these benefits will apply to organisations within the NMM area needed to be investigated. A detailed analysis of the benefits of Project Management and in particular a PMO, have been investigated by means of a literature study. An investigation into the effectiveness of PMO’s in South Africa in general, was conducted by means of a survey targeted at a group of I.T. Project Managers located in all the major centres. A further survey was conducted among local I.T. managers to determine their current level of success and their expectations for the future. When reviewing the expectations of local I.T. management against the performance of Project Managers that are currently operating within PMOs, it is clear that organisations within the NMM area are in need of PMO’s and would certainly benefit from their establishment.
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  • Date Issued: 2007

Estimating erosion of cretaceous-aged kimberlites in the Republic of South Africa through the examination of upper-crustal xenoliths

  • Authors: Hanson, Emily Kate
  • Date: 2007
  • Subjects: Kimberlite -- South Africa , Igneous rocks -- Inclusions -- South Africa , Erosion -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4942 , http://hdl.handle.net/10962/d1005554 , Kimberlite -- South Africa , Igneous rocks -- Inclusions -- South Africa , Erosion -- South Africa
  • Description: he estimation of post-emplacement kimberlite erosion in South Africa through the study of upper-crustal xenoliths is relatively unexplored; however the presence of these xenoliths has been recognized for well over 100 years. Post-emplacement erosion levels of a small number of South African kimberlite pipes have been inferred through the study of the degree of country-rock diagenesis, the depth of sill formation, the depth of the initiation of the diatreme and fission track studies. Through these studies, several estimates were proposed for the Group I Kimberley kimberlites. Although the 1400 m estimate of erosion remains widely accepted today, this estimate relies on the presence of Karoo-like basalt xenoliths in the Group I Kimberley kimberlites, as their presence proves that basalt existed in the Kimberley area when the kimberlites were emplaced. Basaltic xenoliths were described during the early stages of mining in Kimberley, though only one of these descriptions suggests that the ‘basaltic’ boulders correlate with the Karoo basalts. Because of the discrepancy between these early documentations of upper-crustal xenoliths and because the occurrence of Karoo-like basalt xenoliths in the Group I Kimberley kimberlites is under question, a re-investigation of the erosion levels and the upper crustal xenolith suites in South African, Cretaceous-aged kimberlites, including Melton Wold, Voorspoed, Roberts Victor, West End, Record Stone Quarry, Finsch, Markt, Frank Smith, Pampoenpoort, Uintjiesberg, Koffiefontein / Ebenheuyser, Monastery, Kimberley (Big Hole), Kamfersdam , Jagersfontein, Kaal Vallei, De Beers, Bultfontein, Lushof, Britstown Cluster, Hebron and Lovedale, was conducted. This study presents the analytical results for upper-crustal sandstone and basalt xenoliths collected from dumps, excavation pits and borehole core at the above-mentioned kimberlites, and demonstrates that they correlate with stratigraphic units of the Karoo Supergroup on the basis of mineral and geochemical compositions. These upper-crustal xenoliths are incorporated into kimberlites and down-rafted to levels below their stratigraphic position during kimberlite emplacement, consequently recording the broad stratigraphy into which each kimberlite is emplaced. Therefore, the Cretaceous lateral extent of the Karoo Supergroup is inferred and post-emplacement erosion estimated by reconstructing the stratigraphy based on upper-crustal xenolith suites for each kimberlite and calculating the total thickness of the now-eroded units. The distribution of sandstone xenoliths indicates that during the Cretaceous the lateral extent of the Dwyka, Ecca and Beaufort Groups encompassed all of the examined kimberlites, while the ‘Stormberg’ Group was constrained to an area outlined by the Voorspoed and Monastery kimberlites. Similarly, basalt xenoliths occur in all of the Group II and transitional (143 – 100 Ma) kimberlites but only in the Group I (90 – 74 Ma) kimberlites that lie within close proximity to the western outcrop margin of the outcrop area of the Drakensberg Group basalts (Lesotho Remnant), namely Monastery, Jagersfontein and Kaal Vallei. This trend implies an eastward-retreat of the inland erosion front of the Karoo basalts between 140 and 90 Ma and subsequent erosion of the underlying sedimentary units. It also suggests that a thicker succession of Karoo strata was present at the time of Group II and transitional kimberlite emplacement and that there has been more post-emplacement erosion in these kimberlites than the younger Group I kimberlites, except for Monastery, Jagersfontein and Kaal Vallei. Estimates are unique to each kimberlite as they are dependent on both stratigraphic location, elevation and present country rock, and range from approximately 1000 – 2500 m for the older kimberlites and less than 700 m to 1400 m for the younger kimberlites. Furthermore, the upper-crustal xenoliths found at the Group I Kimberley kimberlites and the coinciding trend of basalt erosion demonstrate that Karoo basalts were eroded from the Kimberley area by the time the Group I Kimberley kimberlites erupted (~85 Ma). Therefore, basalts are omitted from the Group I Kimberley kimberlites post-emplacement erosion estimate, and the upper Beaufort Group is considered the upper limit of the stratigraphy that was present at the time of the eruption of the Group I Kimberley pipes. Therefore, the erosion estimates decrease from a previous estimate of 1400 m down to 400 to 1100 m, where 850 m is considered a dependable intermediate estimate.
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  • Date Issued: 2007

Estimating the willingness-to-pay for restoring indigenous vegetation at selected sites in South Africa

  • Authors: Tessendorf, Sharon Erica
  • Date: 2007
  • Subjects: Water resources development -- South Africa , Water-supply -- South Africa , Alien plants -- South Africa , Restoration ecology -- South Africa
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: vital:8999 , http://hdl.handle.net/10948/617 , Water resources development -- South Africa , Water-supply -- South Africa , Alien plants -- South Africa , Restoration ecology -- South Africa
  • Description: The Working for Water (WfW) Programme is a public works programme designed to clear South Africa of invasive alien vegetation and to restore lowwater consuming indigenous vegetation in the areas that have been cleared. Funds to clear alien invasives were initially secured on the basis that such a programme would increase water runoff, facilitate biodiversity and ecosystem functioning, and provide social benefits through job creation. The economic merits of the Programme, in terms of increased water yields, has been established in the Western Cape and KwaZulu-Natal, but questioned in the Eastern and Southern Cape. However, there are economic aspects of the studies carried out in the Eastern and Southern Cape that merit more attention than was given them; one of these being the issue of non-water benefits. Preliminary figures emanating from contingent valuation pilot studies conducted at six WfW projects sites indicated that one of these non-water benefits, namely the biodiversity and ecosystem resilience benefit, could be substantial. As such, the primary objective of the present study was to apply the contingent valuation method (CVM) to value people’s preference for indigenous vegetation. This value was intended to serve as a proxy for increased biodiversity and ecosystem resilience at three WfW sites. Despite the controversy surrounding the CVM, it has been found that it is a credible valuation tool. The CVM’s merits lie in its versatility and in the fact that it is the only method available which is capable of obtaining estimates of both nonuse and use values, thus making it applicable for valuing biodiversity. The primary aim of a CVM study is to determine an estimate of the total willingness-to-pay (WTP). In this study, the total WTP figure was calculated by multiplying the median WTP for the local WfW Programme by the total number of user households. The respective total WTP amounts are shown in Table 1. It was anticipated that respondents would be willing to pay more for the national WfW Programme, than for the less inclusive good (i.e. the local WfW Programme). The results correspond with this expectation at the Port Elizabeth and Underberg sites. However, due to strategic factors Worcester respondents were willing to pay more for the local WfW Programme than for the national Programme.
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  • Date Issued: 2007

Ethnicity and nationalism in urban colonial Zimbabwe : Bulawayo, 1950 to 1963

  • Authors: Msindo, Enocent
  • Date: 2007
  • Language: English
  • Type: Article
  • Identifier: vital:6149 , http://hdl.handle.net/10962/d1006813 , http://dx.doi.org/10.1017/S0021853707002538
  • Description: Zimbabwean historians have not yet fully assessed the interaction of two problematic identities, ethnicity and nationalism, to determine whether the two can work as partners and successfully co-exist. This essay argues that, in Bulawayo during the period studied, ethnicity co-existed with and complemented nationalism rather than the two working as polar opposite identities. Ethnic groups provided both the required leaders who became prominent nationalist figures and the precolonial history, personalities and monuments that sparked the nationalist imagination. From the 1950s, ethnic groups expanded their horizons and provided platforms from which emerging African nationalists launched their agenda. Understanding these interrelationships will reshape our understanding of the workings of these two identities in a cosmopolitan town.
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  • Date Issued: 2007
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