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Development of written information for antiretroviral therapy: comprehension in a Tanzanian population

- Mwingira, Betty, Dowse, Roslind

Authors: Mwingira, Betty , Dowse, Roslind
Date: 2007
Language: English
Type: Article
Identifier: vital:6404 , http://hdl.handle.net/10962/d1006477
Description: Objective To design and develop a simple, easily readable patient information leaflet (PIL) for a commonly used antiretroviral (ARV) regimen and to evaluate its readability and acceptability in a Tanzanian population. Method A PIL incorporating simple text and pictograms was designed for the antiretroviral regimen of stavudine, lamivudine and efavirenz. The PIL was designed according to established good design guidelines, modified during a multi-stage iterative testing process and piloted in a South African Xhosa population. The PIL was made available in both English and Kiswahili. Sixty Tanzanian participants who were not taking ARVs were interviewed. They were asked to read the PIL in the language of their choice and were then asked a series of two-part questions; the first part required participants to locate the information in the PIL, after which they were asked to explain the information in their own words. Acceptability was assessed through close-ended questions and open-ended feedback. The influence of selected patient characteristics on comprehension of the PIL was investigated using one-way ANOVA and t-tests for independent samples with a significance level set at 0.05. Main outcome measure Comprehension of the written information in an overall percentage understanding. Results The overall average percentage comprehension of the PIL was 95%. The target set by the EC guideline that at least 80% of participants correctly locate and understand the information was achieved for 19 of the 20 questions. Five of the six instructions illustrated by pictograms were correctly understood by all participants. The only patient characteristics significantly associated with comprehension were educational level and self-reported ease of reading the PIL. Acceptability of the PIL was high and positive comments were associated with simplicity, good design, easy readability and user-friendliness, the latter enhanced by the inclusion of pictograms. Conclusion The PIL designed for this study was shown to be effective in communicating information about ARVs. Patient characteristics must be taken into account when developing written information, and the final document must be tested for comprehension in the target population.
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Date Issued: 2007

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Die bestuur van die geintegreerde gehaltebestuurstelsel

- James, Raymond Oscar

Authors: James, Raymond Oscar
Date: 2007
Subjects: Total quality management -- South Africa , Quality assurance -- South Africa
Language: Afrikaans
Type: Thesis , Masters , MEd
Identifier: vital:9540 , http://hdl.handle.net/10948/682 , Total quality management -- South Africa , Quality assurance -- South Africa
Description: Die doel van hierdie studie was om te kyk hoe effektief die Geïntegreerde Gehaltebestuurstelsel (GGBS), en wel die taksering van opvoeders, bestuur kan word om positiewe resultate by skole te bereik. Die studie is gedoen binne die Interpretivistiese benadering. Data-invordering is gedoen deur middel van vraelyste, observasie en onderhoude. Die studie het getoon dat opvoeders onseker was, juis omdat die Onderwysdepartement nie die nodige leiding gegee en die nodige hulpbronne gehad het nie. Die afgelope twee jaar ( 2006 en 2007 ) egter het die Departement skouer aan die wiel gesit en hulp aan skole verleen, hetsy deur die beskikbaarstelling van die nodige vorms, of die aanstel van ‘n koördineerder om hulp aan skole te verskaf. Die belangrikste uitkomste van die studie was die besef dat opvoeders se vrese en aannames aangespreek moet word om ‘n gehaltebestuurstelsel effektief te maak. Slypskole moet gehou word om hulp en bystand aan die getakseerdes te verleen. Die bestuurspan van die skool moet ook indiensopleiding ondergaan, sodat hulle presies kan weet wat van hulle verwag word. Op hierdie manier word onsekerhede uit die weg geruim, want onsekerheid was die grootste probleem waarmee opvoeders te kampe gehad het in die implimentering van die GGBS.
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Date Issued: 2007

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Die verbetering van dissipline as 'n sleutelbestuurstaak in 'n skool

- September, Willie Jeffrie

Authors: September, Willie Jeffrie
Date: 2007
Subjects: Classroom management -- South Africa , School discipline -- South Africa , School management teams
Language: Afrikaans
Type: Thesis , Masters , MEd
Identifier: vital:9542 , http://hdl.handle.net/10948/679 , Classroom management -- South Africa , School discipline -- South Africa , School management teams
Description: Die doel van hierdie studie is om die dissiplinêre probleme in skole soos dit in die Oudtshoorn-omgewing voorkom, te identifiseer en aan te spreek. Dit word gedoen deur te let op: • die skoolklimaat wat by 'n skool heers en die uitwerking van die skoolklimaat op die dissipline van`n skool. • die dissiplinêre probleme wat met skooldissipline in skole ervaar word. • die oorsake van skooldissipline en in watter mate die omgewing waarin die skool geleë is 'n invloed op skooldissipline het en • om oplossings vir dissiplinêre probleme soos vasgestel aan die hand te doen. Die studie poog om deur kwalitatiewe navorsingsmetodes vas te stel hoe prinsipale, opvoeders en leerders die huidige dissiplinêre situasie in skole ervaar. Dit poog dus om eerstehandse kennis te verkry van hul denke, gevoelens en gedagtes en hoe hierdie fenomeen hulle beïnvloed. Die studie kyk ook in watter mate skoolklimaat op die breë spektrum van skooldissipline 'n invloed het, en hoe die verbetering van skooldissipline `n sleutelbestuurstaak in 'n skool is. Die belangrikste bevindinge van die studie is dat daar samewerking tussen opvoeders en ouers moet wees om negatiewe leerdergedrag aan te spreek. Die studie dui ook aan dat kommunikasie tussen alle rolspelers van uiterse belang is om die dissiplinêre probleme binne skole aan bande te lê. Skoolleierskap moet hulle ook vergewis van die jongste metodes om dissiplinêre probleme aan te spreek. 'n Positiewe skoolklimaat of kultuur is ondersteunend om skooldissipline te verbeter.
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Date Issued: 2007

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Direct-use values of non-timber forest products from two areas on the Transkei Wild Coast

- Shackleton, Charlie M, Timmermans, Herman G, Nongwe, N, Hamer, Nicholas G, Palmer, N R

Authors: Shackleton, Charlie M , Timmermans, Herman G , Nongwe, N , Hamer, Nicholas G , Palmer, N R
Date: 2007
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/181268 , vital:43714 , xlink:href="https://doi.org/10.1080/03031853.2007.9523764"
Description: It is now widely appreciated internationally that rural communities make extensive use of wild resources, and that this use has significant direct use value. The number of case studies in South Africa that have valued the use of such resources are small, albeit growing. Yet none of them have been from coastal sites, which would include use of marine resources, nor have previous studies included the non-biological resources of sand and clay for building purposes. This paper addresses this gap, through examination of the role and value of wild resources in rural livelihoods of households in the Ntubeni and Cwebe areas of the Transkei Wild Coast in the Eastern Cape. Households used a wide range of resources collected from the surrounding communal lands and the Dwesa Cwebe Nature Reserve. Major differences between the sites were the widespread use of bushmeat, shellfish and building sand at Ntubeni compared with relatively small use of these three resources at Cwebe. These differences resulted in a markedly higher, gross, annual, direct-use value at Ntubeni than at Cwebe. The gross, annual, direct-use value averaged across all resources (excluding medicinal plants) and all households (user and non-users) was over R12 000 at Ntubeni, compared to R4 858 at Cwebe. At Ntubeni over half of the total annual direct-use value was contributed by fish and shellfish, indicating the need for more studies in coastal areas. A similar pattern was not evident at Cwebe, because residents did not have access to a rocky shoreline outside of the marine reserve. Local trade was highly variable, both between resources and between households. Averaging the value of trade across all households (i.e. traders and non-traders), gave a total gross, annual value of R1 660 and R600 at Ntubeni and Cwebe, respectively.
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Date Issued: 2007

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Does 'African mathematics' facilitate access to mathematics?: towards an ongoing critical analysis of ethnomathematics in a South African context

- Horsthemke, Kai, Schäfer, Marc

Authors: Horsthemke, Kai , Schäfer, Marc
Date: 2007
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/141004 , vital:37936 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC20885
Description: Mosibudi Mangena, the Minister of Science and Technology, said in an address to the Annual Congress of the South African Mathematical Society at the University of the Potchefstroom, November 2, 2004: "There is one thing we need to address before anything else. We need to increase the number of young people, particularly blacks and women, who are able to successfully complete the first course in Mathematics at our universities." How is this to be achieved? A popular trend involves a call for the introduction and incorporation of so-called ethnomathematics, and more particularly 'African mathematics', into secondary and tertiary curricula. Although acknowledging the obvious benefits of so-called ethnomathematics, this paper critically analyses three aspects of ethnomathematics that have been neglected in past critiques. Our focus is not on the relationship as such between ethnomathematics and mathematics education. Our critique involves (1) epistemological and logical misgivings, (2) a new look at practices and skills, (3) concerns about embracing 'African mathematics' as valid and valuable - just because it is African.
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Date Issued: 2007

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Does the endangered Knysna seahorse, Hippocampus capensis, have a preference for aquatic vegetation type, cover or height?

- Teske, Peter R, Lockyear, Jaqueline F, Hecht, Thomas, Kaiser, Horst

Authors: Teske, Peter R , Lockyear, Jaqueline F , Hecht, Thomas , Kaiser, Horst
Date: 2007
Language: English
Type: Article
Identifier: vital:6775 , http://hdl.handle.net/10962/d1008082
Description: The Knysna seahorse, Hippocampus capensis, is an endangered teleost confined to three South African estuaries. Its abundance within these systems is low and distributions are patchy. Consequently, monitoring population sizes is labour-intensive. The aim of this study was to establish if Knynsa seahorses are associated with specific regions within the estuaries, on which conservation efforts could concentrate. The relationship of Knysna seahorses with aquatic vegetation was analysed in the Knysna Estuary (the largest of the three estuarine systems inhabited by H. capensis) to determine whether this species shows a preference for a particular plant species, vegetation density or vegetation height. Seahorses were associated with five dominant aquatic plants: Zostera capensis, Caulerpa filiformis, Codium extricatum, Halophila ovalis and Ruppia cirrhosa. Together, these comprised 96% of the submerged objects with which seahorses were associated. The relative abundance of plant species changed along the estuary, but seahorses were present throughout the system, except at the estuary mouth, which was characterized by low plant densities and strong currents. No significant difference was found between the proportion of plant species present in a particular region of the estuary and the proportion of plants that seahorses used as holdfasts. However, when Z. capensis and C. filiformis were present at the same sites, adult seahorses preferred C. filiformis as holdfast. Adult seahorse density (individuals/m²) was significantly correlated with percentage vegetation cover and with holdfast length, but juvenile seahorse density was not. Nonetheless, significantly more adult and juvenile seahorses were found at sites characterized by high vegetation cover (>75%) than at sites with lower cover. Our results indicate that although there is some evidence that Knynsa seahorses prefer certain plant species over others, they are likely to be encountered anywhere in the estuary where aquatic plants are present. Conservation efforts in the Knysna Estuary should thus concentrate on such vegetated areas, which comprise approximately 11% of the total submerged surface area.
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Date Issued: 2007

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Dog Latin, Norman Morrissey : book review

- Beard, Margot

Authors: Beard, Margot
Date: 2007
Language: English
Type: Article
Identifier: vital:6115 , http://hdl.handle.net/10962/d1003828
Description: I have only seen one earlier collection of Morrissey's - his slim volume Seasons (1999). Therein he revealed his enjoyment and interest in haiku. Even the two longer poems in that volume were haiku-like, being brief self-contained stanzas grouped under a single title. His new volume, Dog Latin, consists of sixty short poems primarily concerned with man and nature. A number of these are haiku-like in their brevity ("Edgar on Inclusive Fitness," "Setting Ratbane," "Adam Again"), although they too often do not amount to more than post-it like notes. ("This habit / of holding habits to the wind / -me" is the sum total of the poem "Adam Again.") The epigraph to the whole collection is the final stanza of Robert Frost's "The Need of Being Versed in Country Things," which suggests both Morrissey's interest in the apparently unconsidered minutiae of natural objects and beings, and, it would seem, an admiration of Frost's deceptively plain, unmannered style.
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Date Issued: 2007

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Editorial, 2007

- Lotz-Sisitka, Heila, O’Donoghue, Rob B, Robottom, Ian

Authors: Lotz-Sisitka, Heila , O’Donoghue, Rob B , Robottom, Ian
Date: 2007
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/67345 , vital:29078 , https://www.ajol.info/index.php/sajee/article/view/122733
Description: publisher version , The year 2007 is a significant year for environmental education. It marks 30 years since the first internationally agreed principles of environmental education were developed at Tbilisi, commonly known as the Tbilisi Principles. It is also the year in which human beings apparently are finally ‘waking up’ to the fact that human-induced environmental change is causing impacts which are infinitely complex and difficult to resolve. This year, through various highly publicised and politicised events, people have begun to recognise that it is getting hot on planet Earth, and that the associated social, economic and environmental costs are profoundly disturbing. The Stern Review and the UN Intergovernmental Panel on Climate Change both firmly indicated that human-induced environmental change will threaten human economies and security in ways that are unprecedented in human history.
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Date Issued: 2007

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Education decentralization in the Omaheke Region of Namibia

- Semba, Pecka

Authors: Semba, Pecka
Date: 2007
Subjects: Education -- Namibia Schools -- Decentralization -- Namibia Education and state -- Namibia Educational change -- Namibia
Language: English
Type: Thesis , Masters , MEd
Identifier: vital:1894 , http://hdl.handle.net/10962/d1006114
Description: Before the attainment of independence on 21 March 1990, the people of Namibia were engaged in a protracted struggle against colonialism, racism and apartheid, all of which had denied the majority of the people democracy and development. The people of Namibia therefore did not have power to make decisions on matters that affect their lives and were also not able to determine their own destiny (Ministry of Regional Government and Housing [MoRGH]: 1998:1). After independence, the Namibian government provided for a policy of decentralization under Chapter 12 of the Constitution. After adopting decentralization as state policy in 1996 the government, under the auspices of the Ministry of Regional, Local Government and Housing, embarked upon an implementation process that began in 2003. Education decentralization was included in this process. As my research investigated participants' experience of education decentralization in the Omaheke Region, I conducted an interpretive case study. I employed semi-structured interviews as my main data collection instrument. The quality of my research lies mostly in the authenticity of my thick descriptions where I rely to a large degree on a high ratio of participant to researcher voice. The study has revealed that there is a basic understanding of what education decentralization refers to. Education decentralization is also perceived to provide for the democratization of education through the active participation of all relevant stakeholders - parents, teachers, learners and civil servants - in the education process. However, although there is a basic understanding of what education decentralization entails, there is not necessarily acceptance. The study revealed that many people in Omaheke have reservations about the process of decentralizing education services. Some regard education decentralization as central government "dumping" its responsibility on the Regions. Furthermore, neither the Regional Council, the Regional Education Office, schools, communities nor parents have the capacity to cope with decentralization. The responsibility for overseeing the implementation of decentralization in the Region lies with the Omaheke Regional Council. Education as a decentralized function ought to resort directly under the Regional Council. However, the Regional Education office does not yet operate under the Regional Council. Instead the Education Director continues to report directly to the Permanent Secretary of the Ministry of Education in the capital. In this way an important decentralization structure, the Regional Council, is bypassed and rendered toothless. The data reveal that there is only partial evidence of psychological and structural readiness for education decentralization. Consequently there is little meaningful participation and therefore no sense of ownership among parents, teachers, learners, community-based organizations and political leaders.
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Date Issued: 2007

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Effectiveness of the basic antenatal care package in primary health care clinics

- Snyman, J S

Authors: Snyman, J S
Date: 2007
Subjects: Pregnant women -- Health and hygiene , Hospitals -- Maternity services -- South Africa -- Port Elizabeth -- Evaluation , Maternal health services
Language: English
Type: Thesis , Masters , MCur
Identifier: vital:10037 , http://hdl.handle.net/10948/728 , Pregnant women -- Health and hygiene , Hospitals -- Maternity services -- South Africa -- Port Elizabeth -- Evaluation , Maternal health services
Description: Pregnancy challenges the health care system in a unique way in that it involves at least two individuals – the woman and the fetus. The death rates of both pregnant women (maternal mortality) and newborns (perinatal mortality) are often used to indicate the quality of care the health system is providing. In terms of maternal and perinatal outcomes South Africa scores poorly compared to other upper-middle income countries (Penn-Kekana & Blaauw, 2002:14). The high stillbirth rate compared to the neonatal death rate reflects poor quality of antenatal care. Maternal and perinatal mortality is recognised as a problem and as a priority for action in the Millennium Development Goals (Thieren & Beusenberg, 2005:11). The Saving Mothers (Pattinson, 2002: 37-135) and Saving Babies (Pattinson, 2004:4-35) reports describe the causes and avoidable factors of these deaths with recommendations on how to improve care. The quality of care during the antenatal period may impact on the health of the pregnant woman and the outcome of the pregnancy, in particular on the still birth rate. In primary health care services there are many factors which may impact on and influence the quality of antenatal care. For example with the implementation of the comprehensive primary health care services package (Department of Health, 2001a:21-35) changes at clinic level resulted in a large number of primary health care professional nurses having to provide antenatal care, who previously may only have worked with one aspect of the primary health care package such as minor ailments or childcare. Because skills of midwifery or antenatal care, had not been practiced by some of these professional nurses, perhaps since completion of basic training, their level of competence has declined, and they have not been exposed to new developments in the field of midwifery. The practice of primary health care nurses is also influenced by the impact of diseases not specifically related to pregnancy like HIV/AIDS and tuberculosis. The principles of quality antenatal care are known (Chalmers et al. 2001:203) but despite the knowledge about these principles the maternal and perinatal mortality remains high. The Basic Antenatal Care quality improvement package is designed to assist clinical management and decision making in antenatal care. The implementation of the BANC package may influence the quality of antenatal care positively, which in turn may impact on the outcome of pregnancy for the mother and her baby. The aim of this study was to evaluate the effectiveness of the Basic antenatal care (BANC) package to improve the quality of antenatal care at primary health care clinics.
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Date Issued: 2007

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

- Matemadombo, Fungisai, Westbroek, Philippe, Nyokong, Tebello

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

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

- Tau, Prudence, Nyokong, Tebello

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

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

- Agboola, Bolade, Nyokong, Tebello

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

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

- Tau, Prudence, Nyokong, Tebello

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

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

- Khene, Samson M, Cammidge, Andrew N, Cook, Michael J, Nyokong, Tebello

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

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

- Tau, Prudence Lerato, Nyokong, Tebello

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

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

- Lessing, Joan Susanna

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

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Eluvial chromite resources of the Great Dyke of Zimbabwe

- Musa, Caston Tamburayi

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

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