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Improving sanitization and fertiliser value of dairy manure and waste paper mixtures enriched with rock phosphate through combined thermophilic composting and vermicomposting

  • Authors: Mupondi, Lushian Tapiwa
  • Date: 2010
  • Subjects: Compost , Vermicomposting , Manures , Biodegradation , Waste paper -- South Africa -- Eastern Cape , Thermophilic bacteria , Fertilizers
  • Language: English
  • Type: Thesis , Doctoral , PhD (Soil Science)
  • Identifier: vital:11961 , http://hdl.handle.net/10353/411 , Compost , Vermicomposting , Manures , Biodegradation , Waste paper -- South Africa -- Eastern Cape , Thermophilic bacteria , Fertilizers
  • Description: Thermophilic composting (TC) and vermicomposting (V) are the two most common methods used for biological stabilization of solid organic wastes. Both have their advantages and disadvantages but the proposed method of combining composting and vermicomposting (CV) borrows pertinent attributes from each of the two methods and combines them to enhance overall process and product qualities. Dairy manure and waste paper are two wastes produced in large quantities at the University of Fort Hare. The study was carried out to address the following specific objectives, to determine (i) the effectiveness of combined thermophilic composting and vermicomposting on the biodegradation and sanitization of mixtures of dairy manure and paper waste, (ii) an optimum precomposting period for dairy manure paper waste mixtures that results in vermicomposts of good nutritional quality and whose use will not jeopardize human health, (iii) the effectiveness of phosphate rock (PR) in increasing available P and degradation and nutrient content of dairy manure-paper vermicomposts, (iv) the physicochemical properties of vermicompost substituted pine bark compost and performance of resultant growing medium on plant growth and nutrient uptake. Results of this study revealed that wastes with a C: N ratio of 30 were more suitable for both V and CV as their composts were more stabilized and with higher nutrient contents than composts made from wastes with a C: N ratio of 45. Both V and CV were effective methods for the biodegradation of dairy manure and paper waste mixtures with C: N ratio of 30 but the latter was more effective in the biodegradation of waste mixtures with a C: N ratio of 45. The combinination of composting and vermicomposting eliminated the indicator pathogen E. coli 0157 from the final composts whereas V only managed to reduce the pathogen population. iv A follow up study was done to determine the effects of precomposting on pathogen numbers so as to come up with a suitable precomposting period to use when combine composting dairy manure-waste paper mixtures. Results of this study showed that over 95% of fecal coliforms, E. coli and of E. coli 0157 were eliminated from the wastes within one week of precomposting and total elimination of these and protozoan (oo)cysts achieved after 3 weeks of precomposting. The vermicomposts pathogen content was related to the waste’s precomposting period. Final vermicomposts pathogen content was reduced and varied according to precomposting period. Vermicomposts from wastes precomposted for over two weeks were less stabilized, less humified and had less nutrient contents compared to vermicomposts from wastes that were precomposted for one week or less. The findings suggest that a precomposting period of one week is ideal for the effective vermicomposting of dairy manure-waste paper mixtures. Results of the P enrichment study indicated an increase in the inorganic phosphate and a reduction in the organic phosphate fractions of dairy manure-waste paper vermicompost that were enriched with PR. This implied an increase in mineralization of organic matter and or solubilization of PR with vermicomposting time. Applying PR to dairy manure-waste paper mixtures also enhanced degradation and had increased N and P contents of dairy manure-waste paper vermicomposts. Earthworms accumulated heavy metals in their bodies and reduced heavy metal contents of vermicomposts. A study to determine the physicochemical properties of vermicompost substituted pine bark compost and performance of resultant growing medium on plant growth and nutrient uptake was done. Results obtained revealed that increasing proportions of dairy manure vermicomposts in pine bark compost improved tomato plant height, stem girth, shoot and root dry weights. v Tomatoes grew best in the 40 to 60% CV substituted pine bark and application of Horticote (7:2:1 (22)) fertilizer significantly increased plant growth in all media. Progressive substitution pine bark with dairy manure vermicomposts resulted in a decrease in the percentage total porosity, percentage air space whilst bulk density, water holding capacity, particle density, pH, electrical conductivity and N and P levels increased. Precomposting wastes not only reduced and or eliminated pathogens but also improved the stabilisation and nutrient content of dairy manure waste paper mixtures. The application of PR to dairy manure waste paper mixtures improved the chemical and physical properties of vermicomposts. Earthworms bio-accumulated the heavy metals Cd, Cr, Cu, Pb and Zn whilst the contents of these in the vermicomposts declined. It is, therefore, recommended that dairy manure waste paper mixtures be precomposted for one week for sanitization followed by PR application and vermicomposting for stabilization and improved nutrients contents of resultant vermicomposts. Substitution of pine bark compost with 40 to 60 % PR-enriched vermicompost produced a growing medium with superior physical and chemical properties which supported good seedling growth. However, for optimum seedling growth, supplementation with mineral fertilizer was found to be necessary.
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  • Date Issued: 2010

Improving the sales success at Avusa Publishing Eastern Cape

  • Authors: Gerwel, Ettienne
  • Date: 2010
  • Subjects: Sales management -- South Africa , Advertising, Newspaper -- South Africa , Selling
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: vital:8634 , http://hdl.handle.net/10948/1453 , Sales management -- South Africa , Advertising, Newspaper -- South Africa , Selling
  • Description: Avusa Publishing (East Cape) (APEC) publishes several of the oldest and best known newspaper products in the Eastern Cape. The Eastern Province Herald is currently the oldest daily morning newspaper in South Africa and the average daily circulation of the paper is 25 000. Its main distribution is in the Nelson Mandela Bay Metropolitan area, as well as the area up to the Garden Route and as far East as Port Alfred. APEC also publishes the Weekend Post. According to the financial statements and circulation and advertisement figures of the company, the revenue generated by the company has not increased, but stayed stagnant. In addition to this, the daily circulation of the flagship publication, The Herald, has decreased from 29 000 in 2005 to 24 000 in 2008. As the company only generates revenue from two sources, namely advertising sales and the sale of newspapers, the above mentioned situation negatively affects the financial wellbeing of the company. The management dilemma that needed to be researched was how APEC's circulation and advertising income could be increased. The primary objective of this study was therefore to improve APEC's sales success by investigating the determinants of such sales success. More specifically, the study investigated the influence of determinants such as newsworthiness, value proposition, brand awareness, customer service, customer loyalty, credibility and new media on sales success, as measured by increased circulation and advertising revenue. Convenience sampling was used to select 287 employees working for the company. A mail survey was conducted among these 287 employees, but only 114 usable questionnaires were returned (a response rate of 40 percent). The empirical results revealed that brand awareness, customer loyalty and the use of new media technologies exerted a significantly positive influence on the sales success of APEC. The results further showed that newsworthiness, editorial credibility, value proposition and customer service exerted no significant influence on the APEC’s sales success. Despite the latter findings, the results revealed that there was a high level of trust and loyalty in the editorial content of APEC, as well as the perception of good value for money among both readers and advertisers. The managerial implications of these findings are discussed and areas of future research are recommended.
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  • Date Issued: 2010

In vitro bioactivity of crude extracts of Lippia javanica on clinical isolates of Helicobacter pylori: preliminary phytochemical screening

  • Authors: Nkomo, Lindelwa Precious
  • Date: 2010
  • Subjects: Extracts , Helicobacter pylori , Antibiotics , Drug resistance in microorganisms , Materia medica, Vegetable
  • Language: English
  • Type: Thesis , Masters , MSc (Microbiology)
  • Identifier: vital:11257 , http://hdl.handle.net/10353/508 , Extracts , Helicobacter pylori , Antibiotics , Drug resistance in microorganisms , Materia medica, Vegetable
  • Description: Helicobacter pylori classified as a class 1 carcinogen is a common human pathogen implicated in certain gastrointestinal diseases. Helicobacter pylori infection is acquired mainly in childhood, especially in developing countries. H. pylori infection causes peptic ulcer, duodenitis, gastritis and cancer. The growing resistance of H. pylori to antibiotics used in its treatment as well as other innate limitations of the triple therapy has necessitated a search for alternative treatment from natural sources which could be readily available, less cost effective. The antimicrobial activity of solvents (acetone, ethanol, methanol, chloroform and water) crude extracts of Lippia javanica were investigated against 31 H. pylori strains by the agar well diffusion technique. The minimum inhibitory concentration (MIC) was determined by spectrophotometric analysis at 620 nm using the broth micro dilution method and the rate of kill by broth dilution method. Phytochemical analysis was also performed. H. pylori standard strain NCTC 11638 was included as a positive control. Metronidazole and amoxicillin were used as positive control antibiotics. The ANOVA test was used to analyze the results using SPSS version 17.0. The strains were inhibited by all the extracts with inhibition zones of diameter ranging from 0-36 mm and 0-35 mm for the control antibiotic, clarithromycin. The MIC90 ranged from 0.039- 0.625 mg/mL for acetone; 0.039-1.25mg/mL for methanol, 0.00195-0.313 mg/mL for ethanol; 0.01975-2.5 mg/mL for metronidazole and 0.0048-2.5 mg/mL for amoxicillin. Acetone extract completely inhibited strain PE369C at MIC (0.1 mg/mL) and 2× MIC (0.2 mg/mL) in 18h and at ½× MIC (0.05 mg/mL) in 36h. Strain PE466C was completely inhibited at 4× MIC in 72h. Phytochemical analysis revealed the presence of flavonoids, saponins, tannins, steroids and alkaloids. The results indicate that the extracts of the leaves of L. javanica may contain compounds with anti-H. pylori activity and merits further study to identify the compounds.
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  • Date Issued: 2010

Indigenous technology and culture in the technology curriculum : starting the conversation : a case study

  • Authors: Vandeleur, Sonja
  • Date: 2010
  • Subjects: Curriculum evaluation -- South Africa Curriculum planning -- South Africa Education -- Curricula -- South Africa Technology -- Study and teaching -- South Africa Indigenous peoples -- Education -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:1573 , http://hdl.handle.net/10962/d1003455
  • Description: Since the collapse of apartheid and the first democratic elections of 1994, education in South Africa has undergone fundamental transformation and part of this transformation was the reconstruction of the school curriculum. The new curriculum, known as Curriculum 2005 and developed in 1997, introduced Technology as a new learning area. This study is based on the inclusion of ‘indigenous technology and culture’, a new aspect introduced in a revision of Curriculum 2005. The broad goal of the study was to examine and explore pedagogic practice in relation to the inclusion of ‘indigenous technology and culture’ in the revised National Curriculum Statement for Technology. The study was informed by an examination of literature pertaining to philosophy of technology, indigenous knowledge systems and technology education. The review of the literature highlighted the contested nature of ‘indigenous knowledge systems’. Philosophies on the nature of technological knowledge were reviewed in order to explore the meaning of ‘technology’, and a comparative review of curriculum reform in regard to technology education in various parts of the world was conducted. This study presented an attempt to determine the rationale for the inclusion of ‘indigenous technology and culture’ in the revised National Curriculum Statement for Technology in South Africa and to explore and examine what teachers’ existing practices were in this regard. It also examined a process of participatory co-engagement with a focus group of teachers. This process was an attempt to implement ‘indigenous technology and culture’ of the curriculum in a more meaningful way. A case study approach using an in-depth, interpretive design was used. A questionnaire, document analysis, interviews and focus group discussions were used to conduct the investigation. What emerged from the data analysis was that there was unanimous support for the inclusion of ‘indigenous technology and culture’ in the technology curriculum, but implementation had been problematic. This was partly due to difficulties with the interpretation of this aspect in the curriculum as well as a lack of meaningful teaching and learning for various reasons. The study revealed that teachers face multiple dilemmas in implementing ‘indigenous technology and culture’ as an assessment standard. These dilemmas are pedagogical, political, conceptual, professional and cultural in nature. The intentions of the study were to build a comprehensive understanding of ‘indigenous technology and culture’ and to determine how a focus group of teachers were dealing with this new inclusion. The interpretive study concluded with implications and recommendations for further studies.
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  • Date Issued: 2010

Induced plant responses of different Lantana camara L. (Verbenaceae) varieties to herbivory by Falconia intermedia (distant) (Hemiptera: Miridae)

  • Authors: Heshula, Unathi-Nkosi Lelethu Peter
  • Date: 2010
  • Subjects: Lantana camara -- South Africa -- Eastern Cape , Lantana camara -- Biological control -- South Africa -- Eastern Cape , Biological pest control agents -- South Africa -- Eastern Cape , Weeds -- Biological control -- South Africa -- Eastern Cape , Invasive plants -- Biological control -- South Africa -- Eastern Cape , Hemiptera -- South Africa -- Eastern Cape , Miridae -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5911 , http://hdl.handle.net/10962/d1015368
  • Description: A highly variable invasive shrub, Lantana camara L. (Verbenaceae), has been notoriously difficult to control thus far despite a well established biological control programme in South Africa. A promising leaf-feeding biological control agent, Falconia intermedia (Distant) (Hemiptera: Miridae), released to control this invasive plant eventually crashed at three out of five sites in the Eastern Cape Province. In the Mpumalanga Province, after initially colonising and building up high numbers on the L. camara stands the agent populations crashed. Several reasons for these population crashes have been suggested, but induced plant defences have not been investigated. Although plants face the challenge of herbivory by various organisms while remaining immobile, some plants may possess the ability to induce physical and/or chemical defensive responses following feeding and thus prevent further plant tissue damage and loss. Laboratory trials were conducted to determine the existence, nature and effect of physical and chemical feeding-induced responses of L. camara on the performance of the leaf-feeding biological control agent, F. intermedia. Lantana camara plants used in the study were obtained from five localities in the Eastern Cape Province, South Africa, while the insect culture was established from field populations. Plants from all varieties on which F. intermedia was released significantly increased the toughness of their leaves compared to control treatment plants. In addition, plants from three localities: Lyndhurst Farm, East London and Port Alfred, significantly increased trichome density after prolonged feeding by F. intermedia. On the three varieties showing increases in these two factors (i.e. leaf toughness and trichome density), oviposition, survival and feeding damage by the mirid agent was significantly lower on previously damaged plants. A significant negative correlation between trichome density and population numbers was found (R²= 0.52, p < 0.0003), suggesting that an increase in trichome density strongly contributes to a reduction in F. intermedia's growth. The growth and reproduction of the resistant plants was not significantly impacted by F. intermedia feeding. The defensive responses were found to be plant systemic and rapidly induced as they were elicited and expressed throughout the plant in both damaged and undamaged leaves within five weeks after insect release. Leaf toughness and trichome density were not significantly increased after feeding on plants from Whitney Farm and Heather Glen Farm. On the contrary, mirid individuals performed significantly better on plants from Whitney Farm and Heather Glen Farm than on plants of other varieties, indicating their susceptibility and suitability to the agent and the lack of induced resistance against the agent. Plants from all localities besides East London showed some level of tolerance and overcompensated for feeding damage by increasing plant growth and reproductive factors on plants fed upon. This was however only significant in two variables of the more susceptible localities, Whitney Farm and Heather Glen Farm. This increase in plant fitness did however indicate an induced defence response by these plants to feeding, a response designed to lessen the effects of agent feeding. Headspace volatile analysis was used to investigate any volatile chemical responses by L. camara due to F. intermedia feeding at two of the five localities chosen: East London and Whitney Farm. There was no significant difference in headspace volatiles emitted by leaves of plants from the East London insect infested and control treatment plants. On the Whitney Farm damaged plants however there was a 2.5 fold increase in the emission intensity of one of the three main compounds, later identified as Beta-caryophyllene. Three major chemical constituents which were found to be common to leaf volatiles of the two varieties were identified through gas chromatography-mass spectrometry (GC-MS) from the damaged and undamaged leaves of these two varieties. The methods used in collecting leaf volatiles were shown to be significant in the strength of chromatogram peaks. Using general authentication methods and purified standards, one of these was identified as the sesquiterpene, Beta-caryophyllene (C₁₅H₂₄). This compound is one of the major constituents found in isolations of L. camara varieties worldwide. This is the first such work done on a variety of L. camara in South Africa, and hopefully the beginning of more in-depth studies of the volatile organic chemicals from the numerous naturalised varieties of L. camara. It is suggested that the sum of these responses may play a role bigger than is currently understood in this plant-insect relationship. It is also argued that feeding induced plant defences may play an important role in attempts to control alien plants using insect agents.
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  • Date Issued: 2010

Influence of mite predation on the efficacy of the gall midge Dasineura sp. as a biocontrol agent of Australian myrtle Leptospermum laevigatum (Myrtaceae) in South Africa

  • Authors: Mdlangu, Thabisa Lynette Honey
  • Date: 2010
  • Subjects: Dasyneura leguminicola , Myrtaceae -- South Africa , Mites as biological pest control agents , Pests -- Biological control , Biological pest control agents , Predation (Biology)
  • Language: English
  • Type: Thesis , Masters , MSc (Zoology)
  • Identifier: vital:11789 , http://hdl.handle.net/10353/272 , Dasyneura leguminicola , Myrtaceae -- South Africa , Mites as biological pest control agents , Pests -- Biological control , Biological pest control agents , Predation (Biology)
  • Description: Dasineura sp. is a gall forming midge that was introduced into South Africa for the biocontrol of the Australian myrtle, Leptospermum laevigatum. It causes galls on both the vegetative and reproductive buds of the plant. Although Dasineura sp. was initially regarded as a potentially successful agent, galling up to 99 percent of the buds of the host plant, it has been preyed on by native opportunistic mites, which caused a decline in the performance of the midge as a biocontrol agent of L. laevigatum. This raised a concern about whether this fly will be able to perform effectively in the presence of its new natural enemies. Therefore, the objectives of this study were to: 1) ascertain whether mite abundance has seasonal variations; 2) determine if plant density and plant size have an effect on midge predation by the mites; and 3) determine if midge predation varies in different locations. The study was conducted at three sites in the Hermanus area, Western Cape Province. Every three weeks for thirteen months, galls were collected and dissected so as to count and record the numbers of midge larvae, pupae, adults and mites that were found. Data collected showed that predation varied with season, and the mites were scarce during the flowering season. Predation also varied among the study sites and plant density had an effect on midge predation. Midges in smaller plants (saplings) were more vulnerable to predation than those in the bigger plants (plants from isolates and thickets). It was concluded that although mites have an effect on midge populations, they do not prevent their establishment on the plant. Therefore, a survey should be done in two to three years time to check if the midges are still persisting on the plant, vi and recommendations are that a new agent should be released to supplement the midges.
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  • Date Issued: 2010

Influences on construction project delivery time

  • Authors: Olatunji, Aiyetan Ayodeji
  • Date: 2010
  • Subjects: Construction industry -- South Africa -- Management , Project management -- South Africa , Construction industry -- Economic aspects -- South Africa , Construction industry -- Technological innovations -- South Africa , Construction industry -- Labor productivity -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , DPhil
  • Identifier: vital:9681 , http://hdl.handle.net/10948/1548 , Construction industry -- South Africa -- Management , Project management -- South Africa , Construction industry -- Economic aspects -- South Africa , Construction industry -- Technological innovations -- South Africa , Construction industry -- Labor productivity -- South Africa
  • Description: Construction delays are a global phenomenon. Factors causing construction delays in construction projects differ from country to country, due to different prevailing conditions. The prevailing conditions that could exert an influence on project delivery time are: political, economic, and physical factors as well as level of technological development; management style, and construction techniques. The construction industry is a major player in the economy, generating both employment and wealth. However, many projects experience extensive delays and thereby exceed initial time and cost estimates. This study aims at determining the causes of delays in project delivery in South Africa; evolving interventions, and developing a model for the delivery of projects on time. Inferential and linear regression statistical tools were used in the analysis of data for the study. The sample population consists of architects, builders, quantity surveyors, structural engineers, and clients, and the metropolitan cities of five provinces constituted the geographical delimitation of the study. The provinces are: Eastern Cape; Free State; Gauteng; KwaZulu-Natal, and Western Cape. The metropolitan cities are: Bloemfontein; Cape Town; Durban; Johannesburg, and Port Elizabeth. Findings which negatively influence project delivery time in South Africa include the following: lack of adequate planning; management style; the lack of constructability reviews of designs; inadequate motivation of workers; economic policies; lack of prompt payment to contractors, and quality of management during design and construction. Recommendations include: (1) The introduction of the following courses in built environment tertiary education � quality management competences; operational planning; design management, and generic management; (2) pre-qualification of suppliers; (3) inclusion of the following in tender documentation � human resource schedule; plant and equipment schedule; quality assurance plan, and work schedule; (4) appointment of materials specialists on a large projects; (5) the model developed should be adopted for use in the South African construction industry for the delivery of projects on time, and (6) the linear regression equation: Y = 13.1159 + 1.1341x or 35.3 percent addition on time for the estimation of project delivery time.
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  • Date Issued: 2010

Informing an ICT intervention for HIV and AIDS education at Rhodes University

  • Authors: Gunzo, Fortunate Takawira
  • Date: 2010
  • Subjects: AIDS (Disease) -- Prevention -- South Africa AIDS (Disease) -- Study and teaching -- South Africa HIV infections -- Prevention -- South Africa HIV infections -- Study and teaching -- South Africa Health education -- South Africa Educational technology -- South Africa Rhodes University -- Students -- Attitudes Counseling in higher education -- South Africa
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1577 , http://hdl.handle.net/10962/d1003459
  • Description: This study captures the process and methods used in selecting and organising content for an ontology. In the Information and Communication Technology (ICT) field ontology refers to a way of organising and storing information and facilitating interaction between the system and its users. Ontologies are being used more frequently to provide services that deal with complex information. In this study, I record my experience of developing content for an HIV and AIDS ontology for Rhodes University students. Using several different methods, I started the process of selecting and organising HIV and AIDS information, free of scientific jargon and prescriptive language, and consisting only of relevant information. I used data derived from interviews with six HIV and AIDS experts to develop questions for a survey that was open to all Rhodes University students. The 689 people who responded to the survey indicated that they needed more information on testing, treatment and living with HIV. Responses also showed that students had a lot of information on HIV prevention and transmission. Four focus group discussions revealed that students were tired of repetitions of the „same‟ information on HIV and AIDS and wanted to know more about life after contracting HIV. Using this data, I propose some guidelines to populate HIV and AIDS ontology. Ontologies can be customized for particular groups of users, for example according to gender, race, year of study etc. Another advantage of the ontology is that it can be expanded or contracted depending on the scope of one‟s intervention.
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  • Date Issued: 2010

Innovation in post production stage of print Newspaper

  • Authors: Fayo, Sicelo Nathaniel
  • Date: 2010
  • Subjects: Newspaper publishing -- Technological innovations , Newspapers -- Circulation , Newspapers -- Marketing
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: vital:8614 , http://hdl.handle.net/10948/1544 , Newspaper publishing -- Technological innovations , Newspapers -- Circulation , Newspapers -- Marketing
  • Description: Print newspapers in South Africa are the oldest formal mode of news and information dissemination but which has come under tremendous pressure with the advent and spread of technological innovation involving information communication infrastructure and processes, but specifically the internet. The main challenge facing print newspapers in terms of circulation growth of print and advertising revenue is speed to market. The internet has not only provided a new avenue for news and information dissemination but has the distinct advantage of tremendous speed to deliver news and information to readers. Meanwhile, print newspapers whose production is still almost entirely dependent on traditional structures, processes and physical mode of delivery are battling to stay afloat as the chase for readers' attention is gaining more ground on digital platforms. This new competition landscape has now cast focus fully on traditional print media‟s production processes competency levels as well as their suitability for the nature of competition posed by digital news platforms. The processes involved in the production of a print newspaper can be described as hybrid (Davis and Heineke. 2005: 220) in that they involve different types of processes at different stages to produce the final product. The focus of this study at Avusa Media (Port Elizabeth) was on the post production processes involving the printing and distribution of printed newspapers with the objective of gaining an understanding of the extent and impact of the information technology advancement in the post production phase of printed newspapers. v In pursuing the goal, the case study research followed a phenomenological paradigm involving exploratory and descriptive research processes as described by Yin (1994) in Collis and Hussey (2003: 69) and Clifford Geertz (1973) in Babbie and Mouton (2005: 272) The research found that the traditional business structure for printed newspapers is increasingly becoming unviable due to poverty of technological innovation in critical parts of the production value chain; namely post production processes that encompass printing and distribution of printed newspapers. The research established and revealed that while there are some technological innovations and advances in the print newspaper publishing industry value chain worldwide, they are not only severely limited and disjointed but are also seemingly moving apart rather than towards consolidation in terms of the speed to market need faced by print newspaper publishers.
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  • Date Issued: 2010

Integer optimisation for the selection of a fantasy league cricket team

  • Authors: Brettenny, Warren James
  • Date: 2010
  • Subjects: Sports -- Research -- Methodology , Teamwork (Sports) , Cricket players
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10565 , http://hdl.handle.net/10948/1230 , Sports -- Research -- Methodology , Teamwork (Sports) , Cricket players
  • Description: Sports fans often scrutinise the team selection strategies employed by their favourite team's coach or selection panel. Many of these fans believe that they can perform the selection process far better than those tasked with the responsibility. Fantasy leagues, provide a platform for fans to test their hand at this selection procedure. Twenty20 cricket is a new and exciting form of cricket and has become very popular in recent years. This research focuses on bringing these concepts together by proposing a binary integer program to determine a team selection strategy for fantasy league cricket. This is done in a Twenty20 setting. The approach used in this study focuses on evaluating the effectiveness of previously developed performance measures in a fantasy league setting. Adjustments to these measures are made and new measures are proposed. These measures are then used to select a fantasy league team using a prospective approach. This is done to provide fantasy league participants with a mathematical procedure for fantasy league team selection.
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  • Date Issued: 2010

Integrated teaching strategies model for improved scientific literacy in second-language learners

  • Authors: Villanueva, Mary Grace Flores
  • Date: 2010
  • Subjects: Science -- Study and teaching (Elementary) -- South Africa , Science -- South Africa -- Methodology , Science -- Curricula
  • Language: English
  • Type: Thesis , Doctoral , DEd
  • Identifier: vital:9514 , http://hdl.handle.net/10948/1107 , Science -- Study and teaching (Elementary) -- South Africa , Science -- South Africa -- Methodology , Science -- Curricula
  • Description: The importance of a scientifically literate society is currently acknowledged both internationally and South Africa. The notion of scientific literacy in South Africa has emerged largely due to the government’s recognition of the role that science and technology plays in economic growth, employment creation, social redress and social development. However, in light of South Africa’s learner performance on international and national assessments such as TIMMS (2003) and PIRLS (2006), as well as the problems of teaching and learning in a second language, there appears to be a primary and pressing need to develop learners’ fundamental sense of scientific literacy (Norris & Phillips, 2003). Expanding learners’ ability to read, write and communicate in science may provide the necessary framework for engaging learners in the critical principles and foundations of the scientific endeavour (Hand, Prain, & Yore, 2001). As such, this study focuses on equipping and training grade six and seven science teachers to develop scientifically literate learners via professional development workshops with a strategy that supports reading, writing, talking and conducting (‘doing’) science through scientific investigations. The typology of triangulation and the mixed method research approach was supported by a fully mixed, concurrent, and equal status design (Leech & Onwuegbuzi, 2007). Quantitative data were collected from the baseline and post-intervention testing of learners’ problem solving skills, as well as their literacy skills in English and isiXhosa. Qualitative measures were generated through classroom observations, teacher interviews and learners’ science notebooks. The study was conducted in two different milieus in the Eastern Cape, South Africa. The first setting, in the rural area of Tyumie Valley near the Hogsback Mountains, was comprised of a sample of grade six and seven (multi-grade classrooms) teachers (n=7) and learners (n=168) from five experimental schools and two comparison schools. The second setting, in the urban townships area east of Port Elizabeth, was comprised of a sample of grade six teachers (n=8) and learners (n=675) from six experimental schools and two comparison schools. Mean differences between the experimental and the comparison groups were computed for the Raven’s Standard Progressive Matrices (RSPM) and the literacy tests, and the data generated were treated with an Analysis of Covariance (ANCOVA). The data suggest that the scientific literacy strategy improved the experimental learners’ problem solving skills. Both experimental groups demonstrated greater gains than that of the comparison schools. However, statistically significant improvements were only detected in Port Elizabeth. Improvements in learners’ literacy skills in isiXhosa and English varied according to each milieu. While the teachers initially identified challenges to learners’ reading and writing abilities, the analysis of learners’ science notebooks suggested that they used writings to support their investigations. Some teachers cited difficulties with certain aspects of the model, such as problems with developing an investigable question and argumentation, yet overall, teachers found the strategy useful for developing learners’ language skills, as well for strengthening their pedagogical practices in science. Teachers’ gradual improvements in the use of the model suggest that they were able to use the scientific literacy strategy to support the cognitive and linguistic development of second-language learners.
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  • Date Issued: 2010

Intertidal patterns and processes : tracking the effects of coastline topography and settlement choice across life stages of the mussels perna perna and mytilus galloprovincialis

  • Authors: Von der Meden, Charles Eric Otto
  • Date: 2010
  • Subjects: Mexilhao mussel -- Behavior -- South Africa Mytilus galloprovincialis -- Behavior -- South Africa Perna -- Behavior -- South Africa Mussels -- Ecology -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5721 , http://hdl.handle.net/10962/d1005407
  • Description: Within landscapes, spatial heterogeneity is common and specific landscape features can influence propagule dispersal by wind or water, affecting population connectivity and dynamics. Coastline topographic features, such as bays and headlands, have a variety of biophysical effects on nearshore oceanography, larval transport, retention and supply, and the processes of larval settlement and recruitment. Although this has been demonstrated in several parts of the world, engendering a perception of a general ‘bay effect’, few studies have investigated this generality in a single experiment or region, by replicating at the level of ‘bay’. The Agulhas biogeographic region of the south coast of South Africa is a useful system within which to test for such generality. Using the intertidal mussels Mytilus galloprovincialis and Perna perna as model organisms, patterns of adult distribution were surveyed across four large ‘halfheart’ bays and intervening stretches of open coast, providing replication at the level of ‘bay’ and duplication of ecologically similar species. In support of a general, pervasive influence of bays on intertidal populations, mussel cover was found to be greater in bays than on the open coast for both species, although the effect was strongest for M. galloprovincialis. To explain this adult distribution, settlement, post-settlement mortality and recruitment were examined over 12mo at the same sites, with the prediction that rates of each would favour larger bay populations. Contrary to this, an interaction between month and bay-status was found, with greater settlement and recruitment on the open coast than in bays reflecting extreme settlement and recruitment events at 3 westerly open coast sites during summer. Re-analysis excluding these outliers, revealed the expected effect, of greater settlement and recruitment in bays. While this indicates the broad generality of the bay effect, it highlights exceptions and the need for replication in time and space when examining landscape effects. Measuring post-settlement mortality required testing small-scale settlement behaviour on established and newly deployed settler collectors. It was found that all settlers preferred collectors with biofilm, but that primary settlers avoided conspecific settlers, while secondary settlers were attracted to them. With discrepancies in settler attraction to new and established collectors accounted for, initial (over 2d) and longer-term (over 7d) post-settlement mortality rates were found to be substantial (ca 60 %) for both species. No topographic effect on p-s mortality was evident. Finally, recruit-settler, adult-recruit and interspecies correlations were examined at regional and local scales. Synergistic (or neutral) effects maintained the initial settlement pattern in recruit and adult populations regionally, but not at local scales; striking interspecies correlations suggested the influence of common regional transport processes. Ultimately, the results emphasize the importance of the direction of effects in different life stages and at different spatial scales, and the possibility that antagonistic effects may mask even strong patterns.
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  • Date Issued: 2010

Investigating factors that negatively influence lean implementation in the Eastern Cape automotive industry

  • Authors: Camagu, Sibo
  • Date: 2010
  • Subjects: Lean manufacturing -- South Africa -- Eastern Cape , Production management -- South Africa -- Eastern Cape , Industrial efficiency , Automobile industry and trade
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: vital:8655 , http://hdl.handle.net/10948/1360 , Lean manufacturing -- South Africa -- Eastern Cape , Production management -- South Africa -- Eastern Cape , Industrial efficiency , Automobile industry and trade
  • Description: In this intensely competitive environment of the global economy, the survival of even the most established manufacturers depends on their ability to continuously improve quality whilst reducing costs. The resulting productivity of producing more with less is the only key to market leadership and sustainable competitive advantage. Changing production methods from mass-production to Lean Manufacturing has become the essential practise for successful manufacturers (Rogers and Sim, 2009). The purpose of this study is to investigate what factors negate the adoption and implementation of Lean Manufacturing as a means to gain competitive advantage. The focus was on companies that have participated in the AIDC Tirisano cluster programme. The study investigated what effect Organisational Culture, Leadership Behaviours, Employee Involvement and Strategy Integration have on Lean Manufacturing adoption and implementation. This study applied the mixed methodologies of qualitative and quantitative approaches using methodological triangulation. A cross sectional analytical survey approach in a descriptive case study was undertaken. The findings from the questions and the interviews from the respondents who participated in the survey indicated that the practices in some companies enable the successful adoption and implementation of Lean Manufacturing whilst in some others the practices will negatively affect the adoption and implementation. The study concludes by stating that South African automotive component manufacturers are under immense pressure to improve quality and reduce costs. Initiatives like Lean Manufacturing should be undertaken in order to bring about these improvements. But this improvement comes about by changing the current way of doing things. Companies need to undertake a total approach when implementing Lean as part of the business strategy and this must be driven by management as leaders and a team culture that involves all employees needs to be present.
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  • Date Issued: 2010

Investigating science teachers' perceptions of the nature of science in the context of curriculum reform in South Africa

  • Authors: Kurup, Rajasekhar Thanukkothu Sankar Pillai
  • Date: 2010
  • Subjects: Science -- Methodology -- South Africa , Science -- Study and teaching -- Philosophy , Science -- Study and teaching -- South Africa -- Evaluation , Science -- Study and teaching -- Curricula -- South Africa , Science -- Study and teaching -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , DEd
  • Identifier: vital:9509 , http://hdl.handle.net/10948/1175 , Science -- Methodology -- South Africa , Science -- Study and teaching -- Philosophy , Science -- Study and teaching -- South Africa -- Evaluation , Science -- Study and teaching -- Curricula -- South Africa , Science -- Study and teaching -- South Africa
  • Description: An adequate understanding of the nature of science (NOS) has become increasingly important for science teachers in South Africa as comprehensive curricular reforms over the past decade include promoting informed understandings of the ontological and epistemological bases of scientific knowledge and the methods of science. The main objective of this study was to explore the NOS understandings held by a sample of science teachers in the Eastern Cape Province of South Africa. Data were generated via questionnaires (n=136), semi-structured interviews (n=31), and classroom observations (n=8). The teacher interviews, which were informed by the questionnaire data, enabled further interrogation of the teachers’ philosophical positions. Their classroom practices were examined within the framework of these philosophical positions and the requirements of the new curriculum. The effect of implicit and explicit instruction in NOS on these teachers’ beliefs and classroom activities was also considered. A mixed-method approach informed by positivist and interpretivist perspectives was used for the collection and analysis of the data. The data suggests that explicit instruction in NOS resulted in more informed conceptions of science and the scientific enterprise, and that these conceptions were reflected, to a degree, in their classroom behaviours. However, it was noted that the teachers in this study often held philosophically eclectic views of the nature of scientific knowledge and how scientists develop ideas. Similarly, the South African National Curriculum Statement portrays science in contrasting ways, i.e. often within a modern/realist framework, but in other instances within postmodern/relativistic understandings (particularly in terms of indigenous knowledge systems). As such, an approach which aims at providing a firm foundation for understanding NOS ideas within a modern/realist perspective before emphasising the postmodern/relativist aspects of the scientific enterprise is suggested for teacher training and curriculum development.
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  • Date Issued: 2010

Investigating the benefits of using selected lean techniques at a South African exhaust manufacturer-a case study

  • Authors: Louw, Andre
  • Date: 2010
  • Subjects: Automobile supplies industry , Factories
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: vital:8617 , http://hdl.handle.net/10948/1518 , Automobile supplies industry , Factories
  • Description: This study investigates the implementation of supermarket-based scheduling of parts at a South African exhaust manufacturing plant. The study firstly investigates the requirements the manufacturer had to contend with in ensuring a valuable contract was won. The nature of the contract is such that it warrants building of a new facility. The design of the facility and the manufacturing processes is of importance as some Lean techniques are employed during these early stages. The research takes the form of a case study and data is collected mainly through interviews with staff, but also from direct observations on the shop-floor. Interviews were conducted with: - key project leaders responsible for the original design and commissioning of the facility; - production managers and technical staff currently operating the plant; and - shop-floor personnel involved in daily production and logistics operations within the plant. The as-built facility and procedures are compared with literature found on the topic of Lean manufacturing. Various findings are recorded, both on conforming to and not conforming to typical Lean theory. Potential changes are suggested in the following areas: - a Pull strategy is proposed to coincide with the appointment of a so-called pacemaker station; - a pacemaker would need to be further supported by a production leveling strategy; - although quality delivered to the customer is reported as very high, potential improvements are still possible by introducing an "at source" approach to reduce rework; and - finally, a Total Productive Maintenance (TPM) program will serve to reduce downtime even further.
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  • Date Issued: 2010

Investigating the effect of various film-forming polymers on the evaporation rate of a volatile component in a cosmetic formulation

  • Authors: Barnard, Carla
  • Date: 2010
  • Subjects: Cosmetic delivery systems , Controlled release preparations , Cosmetics , Polymers , Drugs -- Controlled release
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10377 , http://hdl.handle.net/10948/1498 , Cosmetic delivery systems , Controlled release preparations , Cosmetics , Polymers , Drugs -- Controlled release
  • Description: The topical application of many substances, including drugs, enzymes, moisturizers and fragrances, contributes largely to the cosmetic and pharmaceutical industries. These components are often volatile in nature and dissipate in a matter of hours. When considering the different types of slow release systems, an overwhelming variety of these systems is available. Each one of the systems is unique in a way, and is designed to perform a particular function, whether it facilitates the controlled release of an active into the body via the skin surface (transdermal delivery) or whether it reduces the rate of loss of an active from the skin surface to the surrounding environment. For the purpose of this study, a previously existing fixative formulation which is believed to reduce the rate of loss of an active component to the environment, through film formation on the skin surface, was investigated. Alternative ingredients or components were incorporated together with the original fixative formulation ingredients into an experimental design which investigates the effect of each group of the components present. 18 formulations with various concentrations of the components within the groups and specified upper and lower limits for each component were formulated. The fixative properties of the formulations were analysed through the incorporation of a fixed amount of a simple fragrance molecule, 4- methoxybenzaldehyde, into each formulation and evaporation studies were conducted in an environmental room at 28±1° C over a period of 5 hours followed by gas chromatography analysis and finally data analyses using statistical methods. The most efficient fixative formulation was established using regression analysis. The fragrance compound in this formulation was found to evaporate at a rate of 0.47 g/L per hour. The least efficient fixative formulation lead to the loss of 0.78 g/L of the fragrance component per hour. From the calculated fragrance concentrations, the rate constant for each individual fixative formulation could be calculated and response surface 8 modelling by backward regression was used in order to determine how each component contributes to the rate of loss of the fragrance compound. Since the sum of the original ingredient and its alternative was constant, each of the original ingredients was coupled directly to its alternative and no conclusion could be made about the contribution of individual components. By increasing the concentration of Hydroxypropylcellulose (HPC) 100K and its alternative HPC 140K, while keeping the effects of the other components constant, a decrease in the rate of fragrance loss was observed. The same conclusion could be made when increasing the concentrations of PEG-12 Dimethicone and its alternative cetyl dimethicone (decreases the evaporation rate). An interaction took place between HPC 100K and PEG-12 dimethicone and their alternatives. The negative effect was, however, not as strong as the combined positive effect on the rate of fragrance loss of the individual components HPC and PEG-12 dimethicone. Evidence suggested that the removal of the components polyvinylpyrrolidone and its alternative, polyurethane-32 (Baycusan® C1003), would improve the effectiveness of the fixative formulation in terms of its slow release properties. A confirmation experiment established that the exclusion of these components from the fixative formulation does improve the “slow release” properties thereof. A larger, more intricate design is required to investigate the effect of each one of the individual components and where the sum of the components (original and its alternative) is not constant.
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  • Date Issued: 2010

Investigating the effects of form-focused activities on the Acquisition of articles and pronouns in English amongst Grade 11 Xhosa learners

  • Authors: White, Emma Lindsey
  • Date: 2010
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:8362 , http://hdl.handle.net/10948/1317
  • Description: The main purpose of this dissertation is to investigate if a teaching method called Focus on Form (FonF) in an English as a Second Language (ESL) class is effective in the acquisition of two grammatical forms namely articles ("a", "an" and "the") and a selection of pronouns. In order to test this hypothesis, quantitative research was performed. The analysis of a series of tests was done quantitatively to prove the hypothesis. The dissertation includes a theory section on Social Capital (SC) and discusses why it might play an important part in South Africa and in offering some help to the communities to enable them to help in the education of their children within South Africa. This dissertation is divided into five chapters. The first chapter introduces the problem and explains how South African education, historically, had devastating effects in the past and continues having a far reaching effect on today‟s learners. It discusses why this dissertation focuses on English and highlights how extensively English has spread throughout the world. It contains an explanation of the value of being competent in the English language. The chapter continues with a depiction of the poor pass rates of the end of year high school examinations, The National Senior Certificate (NSC). It explains the significance of the research, the purpose of the study, its theoretical framework and finally what this study proposes. Chapter two is a literature review of the available literature discussing second language acquisition (SLA) and the difference between English as a Foreign Language (EFL) and English as a Second Language (ESL). The chapter continues with a detailed description of how English was taught historically with an explanation of the approach being used in this study. Chapter two continues with details of the historical "Bantu Education Act No 47 of 1953" and the racist policies of the government of the time with an exploration of the effect these policies had on the education of learners. It also specifies the grammatical forms being used in this study. A summary of Black South African English (BSAE) is included accompanied by a description of language transfer. The chapter contains a section on SC, with an explanation of how this term came about historically and what it means. The chapter includes social problems that South Africa is facing today and how these problems tie in with diminished SC. It explains the importance of SC in Education. The chapter concludes with an explanation of how SC can be utilized in communities and why it is important in a democratic country. Chapter three explains the methodology used in this study as that of positivism and that this study in one sense is purely an empirical study and the reasons behind the choice of methodology. It also explains how a section of this study is pragmatic. Although the testing and analysis is purely statistical, the lessons that took place in the classroom, the interpersonal communication combined with the interaction between the learners and the researcher was not quantitative in nature. This interaction had no outright bearing on the results, but allowed the researcher the opportunity to observe and take notes on the experiences of the learners and the researcher in the classroom. These observations included incidents within the lessons and external problems the learners face which are linked to social issues within the literature. The chapter also contains an explanation of the testing instruments used in this study and how they were developed along with the ethical considerations of the study. Chapter four details the statistical results of this study. It also contains the write up of the field notes of the researcher who took note of incidents that happened within the classes. There are some examples of family and personal problems related to the learners and details the environment of the school. Some of these issues tie in with the theory included; illustrating the ideas and concerns associated with SC and demonstrates how these social problems are truly part of each learner‟s life in a township school. Chapter five offers recommendations to English teachers, the Department of Education (DoE) and to future researchers based on the results of Chapter four. It contains a discussion on how the community can increase SC within their own areas and within the schools. This study argues that the Education system is in dire need of help as evidenced by the dismal exam results. It also argues that South Africa has a variety of social problems that are contributing to the overall failure and dropout rate in schools. It offers some general suggestions on how the community can work together to build systems within the community, to help themselves and their children to become educated, productive members of society. The only way for the children of South Africa to succeed is with a good education as their starting point.
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  • Date Issued: 2010

Investigation and development of an e judiciary service for a citizen oriented judiciary system for rural communities

  • Authors: Scott, Mfundo Shakes
  • Date: 2010
  • Subjects: Digital divide -- South Africa -- Eastern Cape , Rural development projects -- South Africa -- Eastern Cape , Community development -- South Africa -- Eastern Cape , User interfaces (Computer systems)
  • Language: English
  • Type: Thesis , Masters , MSc (Computer Science)
  • Identifier: vital:11390 , http://hdl.handle.net/10353/275 , Digital divide -- South Africa -- Eastern Cape , Rural development projects -- South Africa -- Eastern Cape , Community development -- South Africa -- Eastern Cape , User interfaces (Computer systems)
  • Description: One of the factors that contribute towards slow rural development is the presence of the digital divide. An area where the digital divide is still prevalent is the administration of justice within traditional contexts. One of the areas affected by this problem is the Dwesa rural community, situated on the Wild Coast of the former homeland of Transkei, in the Eastern Cape Province of South Africa. To address this problem for the Dwesa community, a research project on developing and implementing an e-Judiciary service was undertaken. The primary objective of this project was to develop a web application to support traditional justice administration in the Dwesa community. Due to the lack of a proper legal environment in this community, the e-Judiciary service acts as a portal for safe-keeping of judicial information. Such a system also serves as a platform for the administration of minor offences that are solved by the traditional courts. Furthermore, it provides a better working environment for traditional judicial leaders and eliminates the difficulty of accessing legal information by the rest of the community. Through the availability and use of the service, community members are provided with understanding and knowledge about judiciary operations and services in their community.
  • Full Text:
  • Date Issued: 2010

Investigation of entomopathogenic fungi for control of false codling moth, Thaumatotibia leucotrata, Mediterranean fruit fly, Ceratitis capitata and Natal fruit fly, C. rosa in South African citrus

  • Authors: Goble, Tarryn Anne
  • Date: 2010
  • Subjects: Insect pests -- Biological control , Tortricidae -- Biological control -- South Africa , Tephritidae -- Biological control -- South Africa , Citrus -- Diseases and pests -- Biological control -- South Africa , Entomopathogenic fungi , Fungi as biological pest control agents , Biological pest control agents
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5723 , http://hdl.handle.net/10962/d1005409 , Insect pests -- Biological control , Tortricidae -- Biological control -- South Africa , Tephritidae -- Biological control -- South Africa , Citrus -- Diseases and pests -- Biological control -- South Africa , Entomopathogenic fungi , Fungi as biological pest control agents , Biological pest control agents
  • Description: The biology of key citrus pests Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae), Ceratitis capitata Wiedemann (Diptera: Tephritidae) and Ceratitis rosa Karsch (Diptera: Tephritidae) includes their dropping from host plants to pupate in the soil below citrus trees. Since most EP fungi are soil-borne microorganisms, the development and formulation of alternative control strategies using these fungi as subterranean control agents, targeted at larvae and pupae in the soil, can potentially benefit existing IPM management of citrus in South Africa. Thus, a survey of occurrence of entomopathogenic fungi was undertaken on soils from citrus orchards and natural vegetation (refugia) on conventionally and organically managed farms in the Eastern Cape Province in South Africa. A method for baiting soil samples with citrus pest T. leucotreta and C. capitata larvae, as well as with the standard bait insect, Galleria mellonella Linnaeus (Lepidoptera: Pyralidae), was implemented. Sixty-two potentially useful entomopathogenic fungal isolates belonging to four genera were collected from 288 soil samples, an occurrence frequency of 21.53%. The most frequently isolated entomopathogenic fungal species was Beauveria bassiana (Balsamo) Vuillemin (15.63%), followed by Metarhizium anisopliae var. anisopliae (Metschnikoff) Sorokin (3.82%). Galleria mellonella was the most effective insect used to isolate fungal species (χ2=40.13, df=2, P≤ 0.005), with a total of 45 isolates obtained, followed by C. capitata with 11 isolates, and T. leucotreta with six isolates recovered. There was a significantly (χ2=11.65, df=1, P≤ 0.005) higher occurrence of entomopathogenic fungi in soil samples taken from refugia compared to cultivated orchards of both organically and conventionally managed farms. No significant differences were observed in the recovery of fungal isolates when soil samples from both farming systems were compared. The physiological effects and host range of 21 indigenous fungal isolates obtained in the Eastern Cape were investigated in the laboratory to establish whether these isolates could be effectively used as biological control agents against the subterranean life stages of C. rosa, C. capitata and T. leucotreta. When these pests were treated with a fungal concentration of 1 x 10⁷ conidia ml⁻¹, the percentage of T. leucotreta adults which emerged in fungal treated sand ranged from 5 to 60% (F=33.295; df=21; P=0.0001) depending on fungal isolate and the percentage of pupae with visible signs of mycosis ranged from 21 to 93% (F= 96.436; df=21; P=0.0001). Based on fungal isolates, the percentage adult survival in C. rosa and C. capitata ranged from 30 to 90% and 55 to 86% respectively. The percentage of C. rosa and C. capitata puparia with visible signs of mycosis ranged from 1 to 14% and 1 to 11% respectively. Deferred mortality due to mycosis in C. rosa and C. capitata adult flies ranged from 1 to 58% and 1 to 33% respectively, depending on fungal isolate. Entomopathogenic fungal isolates had a significantly greater effect on the adults of C. rosa and C. capitata than they did on the puparia of these two fruit fly species. Further, C. rosa and C. capitata did not differ significantly in their response to entomopathogenic fungi when adult survival or adult and pupal mycosis were considered. The relative potency of the four most virulent Beauveria isolates as well as the commercially available Beauveria bassiana product, Bb Plus® (Biological Control Products, South Africa), were compared against one another as log-probit regressions of mortality against C. rosa, C. capitata and T. leucotreta which all exhibited a dose-dependent response. Against fruit flies the estimated LC50 values of all five Beauveria isolates ranged from 5.5 x 10¹¹ to 2.8 x 10¹² conidia/ml⁻¹. There were no significant differences between the relative potencies of these five fungal isolates. When T. leucotreta was considered, isolates: G Moss R10 and G 14 2 B5 and Bb Plus® were significantly more pathogenic than G B Ar 23 B3 and FCM 10 13 L1. The estimated LC₅₀ values of the three most pathogenic isolates ranged from 6.8 x 10⁵ to 2.1 x 10⁶ conidia/ml⁻¹, while those of the least pathogenic ranged from 1.6 x 10⁷ to 3.7 x 10⁷ conidia/ml⁻¹. Thaumatotibia leucotreta final instar larvae were exposed to two conidial concentrations, at four different exposure times (12, 48, 72 and 96 hrs) and showed an exposure time-dependant relationship (F=5.43; df=3; P=0.001). At 1 x 10⁷conidia/ml⁻¹ two Beauveria isolates: G Moss R10 and G 14 2 B5 were able to elicit a response in 50% of test insects at 72 hrs (3 days) exposure. Although a limited amount of mycosis was observed in the puparia of both fruit fly species, deferred adult mortality due to mycosis was high. The increased incidence of adult mortality suggests that post emergence mycosis in adult fruit flies may play a more significant role in field suppression than the control of fruit flies at the pupal stage. The increased incidence of pupal mortality, as well as the relatively low concentrations of conidia required to elicit meaningful responses in T. leucotreta pupae may suggest that pre-emergent control of false codling moth will play a more significant role in field suppression than the control of adult life stages using indigenous isolates of entomopathogenic fungi. Various entomopathogenic fungal application techniques targeted at key insect pests within integrated pest management (IPM) systems of citrus are discussed.
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  • Date Issued: 2010

Investigations of the bioavailability/bioequivalence of topical corticosteroid formulations containing clobetasol propionate using the human skin blanching assay, tape stripping and microdialysis

  • Authors: Au, Wai Ling
  • Date: 2010
  • Subjects: Adrenocortical hormones -- Bioavailability , Drugs -- Therapeutic equivalency , Adrenocortical hormones -- Effectiveness , Adrenocortical hormones -- Testing , Adrenocortical hormones -- Side effects , Transdermal medication
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:3743 , http://hdl.handle.net/10962/d1003221 , Adrenocortical hormones -- Bioavailability , Drugs -- Therapeutic equivalency , Adrenocortical hormones -- Effectiveness , Adrenocortical hormones -- Testing , Adrenocortical hormones -- Side effects , Transdermal medication
  • Description: Currently, clinical trials in patients are required by most regulatory authorities for the assessment of bioequivalence of topical products where the drug is not intended for systemic absorption. Hence there is a dire need for suitable methods for the assessment of bioavailability and bioequivalence of such products since clinical safety and efficacy studies are expensive, time-consuming and require very large numbers of patients. Except for topical corticosteroid products where the human skin blanching assay/vasoconstrictor assay has been approved by the US FDA for bioequivalence assessment of those products, no other method has been “officially” approved for use in those investigations. However, a few alternative methods such as tape stripping and microdialysis have been pursued and considered to have the potential for use in ioequivalence/bioavailability studies. The human skin blanching assay was used to assess the bioequivalence of commercially available topical products containing 0.05% clobetasol propionate. Both visual and chromameter data were obtained and a commercially available topical corticosteroid product, Dermovate® cream was used as both the “Test” and the “Reference” product. The results indicated that both visual and chromametric assessments were comparable to each other and that either could be used for the assessment of the bioequivalence of topical products containing clobetasol propionate. The screening procedure was optimized to identify potential “detectors” for inclusion in the bioequivalence studies. This resulted in fewer subjects being required in a bioequivalence pivotal study, still having the necessary power to confirm bioequivalence using the human skin blanching assay. Another objective of this research was to re-visit tape stripping and other possible alternative methods such as dermal microdialysis and to optimize these procedures for bioequivalence assessment of topical formulations where the drug is not intended for systemic absorption. In the past few decades, tape stripping has been used to investigate bioavailability/bioequivalence of various topical formulations. This technique involves the removal of the stratum corneum to assess drug penetration through the skin. A draft FDA guidance for tape stripping was initially published but was subsequently withdrawn due to high variability and poor reproducibility. This research project used an optimized tape stripping procedure to determine bioavailability and establish bioequivalence between three commercially available formulations containing 0.05 % m/m clobetasol propionate. Furthermore, tape stripping was validated by undertaking a study to assess the bioequivalence of a 0.05% topical cream formulation (Dermovate® cream) using the same cream as both the “Test” and “Reference” product, in which bioequivalence was confirmed. The findings highlight the potential of tape stripping as an alternative method for the assessment of bioequivalence of clobetasol propionate formulations and may possibly be extended for use in other topical products. Microdialysis is another useful technique that can assess the penetration of topically applied substances which diffuses through the stratum corneum and into the dermis. Microdialysis has previously been successfully used for in vivo bioavailability and bioequivalence assessments of topical formulations. However, the drugs which were under investigation were all hydrophilic in nature. A major problem with the use of microdialysis for the assessment of lipophilic substances is the binding/adherence of the substance to the membrane and other components of the microdialysis system. As a result, this necessitates the development of a microdialysis system which can be used to assess lipophilic drugs. Intralipid® 20% was investigated and successfully utilized as a perfusate to recover a lipophilic topical corticosteroid, clobetasol propionate, in microdialysis studies. Hence, the bioavailability of clobetasol propionate from an extemporaneous preparation was determined in healthy human volunteers using microdialysis. These findings indicate that in vivo microdialysis can be used to assess lipophilic drug penetration through the skin. A novel approach to investigate drug release from topical formulations containing 0.05% clobetasol propionate using in vitro microdialysis was also undertaken. The in vitro findings were found to be in agreement with the results obtained using tape stripping to assess bioequivalence of the same commercially available products, namely Dermovate® cream, Dovate® Cream and Dermovate® ointment. These results indicate the potential to correlate in vitro with in vivo data for bioequivalence assessment of such topical dosage forms.
  • Full Text:
  • Date Issued: 2010
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