Analysis of the anti-cancer activity of novel indigenous algal compounds in breast cancer: towards the development of a model for screening anti-cancer stem cell activity
- Authors: Lawson, Jessica Clair
- Date: 2010
- Subjects: Breast -- Cancer , Breast -- Cancer -- Chemotherapy , Breast -- Cancer -- Treatment , Red algae , Brown algae , Algae -- Biotechnology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3925 , http://hdl.handle.net/10962/d1003984 , Breast -- Cancer , Breast -- Cancer -- Chemotherapy , Breast -- Cancer -- Treatment , Red algae , Brown algae , Algae -- Biotechnology
- Description: Breast cancer, the most common malignancy diagnosed in women, is one of the leading causes of death in women worldwide. In South Africa only 32% of women diagnosed with advanced breast cancer survive more than five years. The search for new chemotherapeutic agents capable of effectively treating breast cancer is therefore essential. Recent evidence supporting the cancer stem cell theory of cancer development for breast cancer challenges the current theories of cancer development and hence treatment. Cancer stem cells are a small subpopulation of tumour cells that possess properties of both cancer cells and stem cells and are believed to be the tumour-initiating population of many cancers. Cancer stem cells are inherently resistant to many chemotherapeutic agents and in this way have been associated with repopulation of tumours after chemotherapy. This phenomenon is proposed as a possible mechanism for cancer relapse after treatment. Cancer stem cells have also been implicated in metastasis, the major cause of mortality in cancer patients. Therefore, any treatment that is capable of targeting and removing breast cancer stem cells may have the theoretical potential to effectively treat breast cancer. However, there are currently no such treatments available for clinical use. We were provided access to a library of novel indigenous small molecules isolated from red and brown algae found off the Eastern Cape of South Africa. The aim of this project was to analyse the anti-cancer and anti-cancer stem cell properties of the compounds in this library and to identify „hit‟ compounds which could form the basis for future development into new anti-cancer drugs. Ten novel compounds of algal origin were tested for cytotoxicity, by determining their ability to inhibit the growth of MCF12A breast epithelial cells and MCF7 breast cancer cells using the colorimetric MTT [(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] cell proliferation assay. All but one of the compounds tested exhibited cytotoxicity towards the MCF7 cancer cell line, with IC50 values (the concentration of the compound that leads to a 50% inhibition in cell growth) of between 3 μM and 90 μM. The chemotherapeutic drug paclitaxel was used as a positive control. Four of the compounds (RUMB-001, RUMB-002, RUMB-007 and RUMB-010/saragaquinoic acid) were significantly more toxic to the MCF7 cancer cell line, than the „normal‟ MCF12A breast cells and were selected as priority compounds for further analyses. In addition, two other compounds were selected as priority compounds, one highly cytotoxic towards both MCF12A and MCF7 cell lines (RUMB-015) and one which was non toxic to either cell line (RUMB-017/018). Preliminary studies into the mechanism of cytotoxicity using Western blot analysis for poly (ADP-ribose) polymerase (PARP) cleavage and Hoechst 33342 immunostaining in MCF-7 cells were largely unsuccessful. The Hoechst 33342 immunostaining assay did provide tentative evidence that selected priority compounds were capable of inducing apoptosis, although these assays will need to be repeated using a less subjective assay to confirm the results. The priority compounds were subsequently investigated for their cytotoxic effect on the cancer stem cell-enriched side population in MCF7 cells. The ability of the priority compounds to selectively target the cancer stem cell containing side population was assessed using two complementary flow cytometry-based techniques – namely the Hoechst 33342-exclusion assay, and fluorescent immunostaining for the expression of the putative cancer stem cell marker, ABCG2+. The ABCG2+ staining assay was a novel technique developed during the course of this study. It remains to be fully validated, but it may provide a new and reliable way to identify and analyse cancer stem cell containing side population cells. The MCF7 cells were treated with the compounds and the proportion of putative cancer stem cells compared with the size of the population in untreated cells was assessed. Three compounds (RUMB-010, RUMB-015 and RUMB-017/018) capable of reducing the proportion of side population cells within the MCF7 cell line were identified. Taking these data together, we identified two potential „hit‟ compounds which should be prioritised for future research. These are compounds RUMB-010/sargaquinoic acid and RUMB-017/018. RUMB-010 is of interest as it was shown to target the putative cancer stem cell population, in addition to the bulk MCF7 tumour line, but was relatively less toxic to the „normal‟ MCF12A cell line. RUMB-017/018 is of interest due to the ability to selectively target the cancer stem cell enriched side population, while having little effect on the normal (MCF12A) or bulk tumour (MCF7) cell lines tested. These compounds will be important as „hit‟ compounds for drug development and as tool compounds to study cancer and cancer stem cell biology.
- Full Text:
- Date Issued: 2010
- Authors: Lawson, Jessica Clair
- Date: 2010
- Subjects: Breast -- Cancer , Breast -- Cancer -- Chemotherapy , Breast -- Cancer -- Treatment , Red algae , Brown algae , Algae -- Biotechnology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3925 , http://hdl.handle.net/10962/d1003984 , Breast -- Cancer , Breast -- Cancer -- Chemotherapy , Breast -- Cancer -- Treatment , Red algae , Brown algae , Algae -- Biotechnology
- Description: Breast cancer, the most common malignancy diagnosed in women, is one of the leading causes of death in women worldwide. In South Africa only 32% of women diagnosed with advanced breast cancer survive more than five years. The search for new chemotherapeutic agents capable of effectively treating breast cancer is therefore essential. Recent evidence supporting the cancer stem cell theory of cancer development for breast cancer challenges the current theories of cancer development and hence treatment. Cancer stem cells are a small subpopulation of tumour cells that possess properties of both cancer cells and stem cells and are believed to be the tumour-initiating population of many cancers. Cancer stem cells are inherently resistant to many chemotherapeutic agents and in this way have been associated with repopulation of tumours after chemotherapy. This phenomenon is proposed as a possible mechanism for cancer relapse after treatment. Cancer stem cells have also been implicated in metastasis, the major cause of mortality in cancer patients. Therefore, any treatment that is capable of targeting and removing breast cancer stem cells may have the theoretical potential to effectively treat breast cancer. However, there are currently no such treatments available for clinical use. We were provided access to a library of novel indigenous small molecules isolated from red and brown algae found off the Eastern Cape of South Africa. The aim of this project was to analyse the anti-cancer and anti-cancer stem cell properties of the compounds in this library and to identify „hit‟ compounds which could form the basis for future development into new anti-cancer drugs. Ten novel compounds of algal origin were tested for cytotoxicity, by determining their ability to inhibit the growth of MCF12A breast epithelial cells and MCF7 breast cancer cells using the colorimetric MTT [(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] cell proliferation assay. All but one of the compounds tested exhibited cytotoxicity towards the MCF7 cancer cell line, with IC50 values (the concentration of the compound that leads to a 50% inhibition in cell growth) of between 3 μM and 90 μM. The chemotherapeutic drug paclitaxel was used as a positive control. Four of the compounds (RUMB-001, RUMB-002, RUMB-007 and RUMB-010/saragaquinoic acid) were significantly more toxic to the MCF7 cancer cell line, than the „normal‟ MCF12A breast cells and were selected as priority compounds for further analyses. In addition, two other compounds were selected as priority compounds, one highly cytotoxic towards both MCF12A and MCF7 cell lines (RUMB-015) and one which was non toxic to either cell line (RUMB-017/018). Preliminary studies into the mechanism of cytotoxicity using Western blot analysis for poly (ADP-ribose) polymerase (PARP) cleavage and Hoechst 33342 immunostaining in MCF-7 cells were largely unsuccessful. The Hoechst 33342 immunostaining assay did provide tentative evidence that selected priority compounds were capable of inducing apoptosis, although these assays will need to be repeated using a less subjective assay to confirm the results. The priority compounds were subsequently investigated for their cytotoxic effect on the cancer stem cell-enriched side population in MCF7 cells. The ability of the priority compounds to selectively target the cancer stem cell containing side population was assessed using two complementary flow cytometry-based techniques – namely the Hoechst 33342-exclusion assay, and fluorescent immunostaining for the expression of the putative cancer stem cell marker, ABCG2+. The ABCG2+ staining assay was a novel technique developed during the course of this study. It remains to be fully validated, but it may provide a new and reliable way to identify and analyse cancer stem cell containing side population cells. The MCF7 cells were treated with the compounds and the proportion of putative cancer stem cells compared with the size of the population in untreated cells was assessed. Three compounds (RUMB-010, RUMB-015 and RUMB-017/018) capable of reducing the proportion of side population cells within the MCF7 cell line were identified. Taking these data together, we identified two potential „hit‟ compounds which should be prioritised for future research. These are compounds RUMB-010/sargaquinoic acid and RUMB-017/018. RUMB-010 is of interest as it was shown to target the putative cancer stem cell population, in addition to the bulk MCF7 tumour line, but was relatively less toxic to the „normal‟ MCF12A cell line. RUMB-017/018 is of interest due to the ability to selectively target the cancer stem cell enriched side population, while having little effect on the normal (MCF12A) or bulk tumour (MCF7) cell lines tested. These compounds will be important as „hit‟ compounds for drug development and as tool compounds to study cancer and cancer stem cell biology.
- Full Text:
- Date Issued: 2010
Analysis processes as antecedents for decision-making related to growth strategies of South African Game Ranchers
- Authors: Van Eyk, Marlé
- Date: 2010
- Subjects: Tourism -- Marketing , Game farms -- South Africa
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9356 , http://hdl.handle.net/10948/1546 , Tourism -- Marketing , Game farms -- South Africa
- Description: Game ranching offers an economic alternative to conventional stock farming and is a means of supplementing income derived from agricultural activities. Competition is intensifying as ranchers continuously look for ways to improve and expand their businesses and gain a competitive advantage. Ranchers consequently have to find strategies that can ensure growth. Since a reciprocal relationship and dependency exists between a game ranch and the environment in which it operates, it is essential that ranchers take cognizance of aspects in the marketing environment that can either limit, and hence encumber the choice of growth strategy, or stimulate the growth potential of game ranches. As the objective of marketing is to offer customers superior value, it is pertinent for ranchers to know and understand the needs, requirements and motivations of visitors. Failure to do so will cause visitors to patronise other game ranches, or alternative tourism offerings that meet their expectations. A literature review was conducted to define strategy and assist in identifying growth strategies available to a game ranch. The literature review assisted in categorising elements in the external, internal and customer analysis phases of strategic marketing management. Surveys were conducted by means of self-completion questionnaires which were distributed throughout South Africa. Two sets of questionnaires were distributed - one to respondents with prior experience of a game ranch, and one to respondents with no-prior experience. A qualifying question directed the fieldworker to decide which questionnaire should be completed by the respondent. The surveys were constructed in such a way as to determine to what extent various factors would persuade respondents to visit a ranch or extend their stay. Based on a factor analysis, an eight factor structure emerged which represented the personal values of respondents and their levels of expectation for each of the factors. The eight factors were stimulation, universalism, tradition, security, hedonism, power, socialisation, and self-direction. The study revealed the following. - The majority of respondents with no-prior experience of a game ranch is either unaware of the offerings of game ranches, or perceives them as too expensive. - The sustainable use of natural resources is not only essential for the existence of a game ranch, but is also an important motivator for respondents to either visit a game ranch or extend their stay at a ranch. - Staff play a critical role in the overall experience of visitors and act as an important motivator to either visit/revisit a game ranch or extend their stay at the ranch. - Clean and comfortable overnight facilities are deemed important by all respondents. - Respondents have a strong desire to relax and spend time with family and friends. A decision-making framework from which game ranches can select applicable growth strategies resulted from the study. The decision-making framework comprises a three-phase process; phase 1 is the identification of a game ranch's target market; phase 2 is the use of a simplistic framework to determine a possible growth strategy for a game ranch; phase 3 is the identification of ways to implement the selected strategy. As the game ranch industry makes significant contributions to the economic, social and ecological welfare of South Africa, this study added to the body of knowledge of game ranching in South Africa, particularly with regard to the growth options available to game ranches. Recommendations for consideration of future research included the following. - As the current study investigated hunting and tourism, future research on growth strategies for game ranches could also include other aspects of game ranching such as the sale of live game and game products. - More focused empirical research into external and internal strategic analysis should be considered to supplement the empirical research into customer analysis resulting from the current study. - Finally, additional information obtained on the external and internal strategic analysis process could lead to expanding the decision-making framework developed in this study into a more holistic tool to be used in selecting a growth strategy, or combination of strategies for a game ranch3.
- Full Text:
- Date Issued: 2010
- Authors: Van Eyk, Marlé
- Date: 2010
- Subjects: Tourism -- Marketing , Game farms -- South Africa
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9356 , http://hdl.handle.net/10948/1546 , Tourism -- Marketing , Game farms -- South Africa
- Description: Game ranching offers an economic alternative to conventional stock farming and is a means of supplementing income derived from agricultural activities. Competition is intensifying as ranchers continuously look for ways to improve and expand their businesses and gain a competitive advantage. Ranchers consequently have to find strategies that can ensure growth. Since a reciprocal relationship and dependency exists between a game ranch and the environment in which it operates, it is essential that ranchers take cognizance of aspects in the marketing environment that can either limit, and hence encumber the choice of growth strategy, or stimulate the growth potential of game ranches. As the objective of marketing is to offer customers superior value, it is pertinent for ranchers to know and understand the needs, requirements and motivations of visitors. Failure to do so will cause visitors to patronise other game ranches, or alternative tourism offerings that meet their expectations. A literature review was conducted to define strategy and assist in identifying growth strategies available to a game ranch. The literature review assisted in categorising elements in the external, internal and customer analysis phases of strategic marketing management. Surveys were conducted by means of self-completion questionnaires which were distributed throughout South Africa. Two sets of questionnaires were distributed - one to respondents with prior experience of a game ranch, and one to respondents with no-prior experience. A qualifying question directed the fieldworker to decide which questionnaire should be completed by the respondent. The surveys were constructed in such a way as to determine to what extent various factors would persuade respondents to visit a ranch or extend their stay. Based on a factor analysis, an eight factor structure emerged which represented the personal values of respondents and their levels of expectation for each of the factors. The eight factors were stimulation, universalism, tradition, security, hedonism, power, socialisation, and self-direction. The study revealed the following. - The majority of respondents with no-prior experience of a game ranch is either unaware of the offerings of game ranches, or perceives them as too expensive. - The sustainable use of natural resources is not only essential for the existence of a game ranch, but is also an important motivator for respondents to either visit a game ranch or extend their stay at a ranch. - Staff play a critical role in the overall experience of visitors and act as an important motivator to either visit/revisit a game ranch or extend their stay at the ranch. - Clean and comfortable overnight facilities are deemed important by all respondents. - Respondents have a strong desire to relax and spend time with family and friends. A decision-making framework from which game ranches can select applicable growth strategies resulted from the study. The decision-making framework comprises a three-phase process; phase 1 is the identification of a game ranch's target market; phase 2 is the use of a simplistic framework to determine a possible growth strategy for a game ranch; phase 3 is the identification of ways to implement the selected strategy. As the game ranch industry makes significant contributions to the economic, social and ecological welfare of South Africa, this study added to the body of knowledge of game ranching in South Africa, particularly with regard to the growth options available to game ranches. Recommendations for consideration of future research included the following. - As the current study investigated hunting and tourism, future research on growth strategies for game ranches could also include other aspects of game ranching such as the sale of live game and game products. - More focused empirical research into external and internal strategic analysis should be considered to supplement the empirical research into customer analysis resulting from the current study. - Finally, additional information obtained on the external and internal strategic analysis process could lead to expanding the decision-making framework developed in this study into a more holistic tool to be used in selecting a growth strategy, or combination of strategies for a game ranch3.
- Full Text:
- Date Issued: 2010
Analytical methods for the quantitative determination of oxytocin
- Chaibva, Faith A, Walker, Roderick B
- Authors: Chaibva, Faith A , Walker, Roderick B
- Date: 2010
- Language: English
- Type: Article
- Identifier: vital:6353 , http://hdl.handle.net/10962/d1006037
- Description: Oxytocin is a clinically important nonapeptide that is used for the induction and/or augmentation of labor and is normally administered as a slow intravenous infusion diluted with normal saline or Ringer’s lactate solution. Oxytocin is also indicated for use in the prevention and treatment of post partum hemorrhage and may be administered via either the intramuscular or intravenous routes in order to increase uterine tone and/or reduce bleeding. The analysis of oxytocin in different media has evolved over the past 30 years with the result that more sophisticated, selective and sensitive techniques are used for the determination of the compound. A variety of techniques have been applied to the determination of oxytocin in different matrices ranging from simple paper chromatography to hyphenated liquid chromatographic such as liquid chromatography coupled with mass-spectrometry. Additionally enzyme linked immuno-sorbent assays (ELISA) and radio immuno-assays (RIA) are used for the determination of low concentrations of oxytocin in biological matrices. This manuscript provides a systematic survey of the analytical methods that have been reported for isolation and quantitation of oxytocin in different matrices.
- Full Text:
- Date Issued: 2010
- Authors: Chaibva, Faith A , Walker, Roderick B
- Date: 2010
- Language: English
- Type: Article
- Identifier: vital:6353 , http://hdl.handle.net/10962/d1006037
- Description: Oxytocin is a clinically important nonapeptide that is used for the induction and/or augmentation of labor and is normally administered as a slow intravenous infusion diluted with normal saline or Ringer’s lactate solution. Oxytocin is also indicated for use in the prevention and treatment of post partum hemorrhage and may be administered via either the intramuscular or intravenous routes in order to increase uterine tone and/or reduce bleeding. The analysis of oxytocin in different media has evolved over the past 30 years with the result that more sophisticated, selective and sensitive techniques are used for the determination of the compound. A variety of techniques have been applied to the determination of oxytocin in different matrices ranging from simple paper chromatography to hyphenated liquid chromatographic such as liquid chromatography coupled with mass-spectrometry. Additionally enzyme linked immuno-sorbent assays (ELISA) and radio immuno-assays (RIA) are used for the determination of low concentrations of oxytocin in biological matrices. This manuscript provides a systematic survey of the analytical methods that have been reported for isolation and quantitation of oxytocin in different matrices.
- Full Text:
- Date Issued: 2010
Antibiotic use in two hospitals in West Wollega, Ethiopia
- Authors: Banja, Wakweya Dugassa
- Date: 2010
- Subjects: Antibiotics , Bacterial diseases -- Chemotherapy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10141 , http://hdl.handle.net/10948/1263 , Antibiotics , Bacterial diseases -- Chemotherapy
- Description: In the last decades, there has been an escalating consumption of antibiotics with the number of antibiotic prescriptions increasing worldwide. Overuse or inappropriate use of antibiotics has resulted in a major increase in the development of multi-drug resistant pathogens. Antimicrobial resistance is one of the world’s most serious public health problems with great implication in terms of morbidity, mortality, and costs. To date, there has been no formal antibiotic use study conducted in the West Wollega zone of Ethiopia to assess antibiotic utilization. The objective of this study was to determine the pattern of antibiotic use in two hospitals in the West Wollega zone of Ethiopia, namely Gimbie Adventist Hospital and Nedjo Hospitals, using drug utilization metrics and the costs associated. In addition it was to assess the correlation between diagnosed infectious diseases and antibiotic prescriptions. This study was a cross-sectional, retrospective, descriptive review of antibiotic usage in the two hospitals in the year 2007. Prescriptions dispensed in the first month of each quarter of 2007 were reviewed. The number of prescriptions screened, antibiotic courses started, antibiotic days by specific agent and overall, the cost of individual and all antibiotics, the number and type of infectious diseases diagnosed were collected from which core drug use indicators were calculated. The correlation between infectious disease diagnosed and the antibiotic days prescribed were analyzed. A total of 18568 antibiotic and non-antibiotic prescriptions were reviewed retrospectively in the four months of the study period, 47 percent of which contained at least one antibiotic. The average number of antibiotics per prescription was 1.33 and 1.09 whilst the percentage of injectable antibiotics prescribed was 83.2 percent and 3.76 percent to outpatients and inpatients respectively. Antibiotics prescribed from the Essential Drug List (EDL) and List of Drugs for District Hospital (LDDH) were 63.0 percent, 74.8 percent, and 90.8 percent and 76.1 percent for outpatients and inpatients respectively. 98.6 percent of outpatient and 97.0 percent inpatient prescribed antibiotics were actually dispensed. Penicillins and quinolones were the most prescribed antibiotics in both inpatient and outpatient departments constituting 43.46 percent and 24.08 percent respectively. The antibiotic utilization ratio, incidence of outpatient antibiotic use, incidence of inpatient antibiotic use, the number of Defined Daily Doses (DDD)/1000inhabitants/year and DDD/100 Occupied Bed Days (OBD) for the zone was 0.16, 17.25, 23.56, 158.61, and 70 respectively. Antibiotic cost constituted 33.7 percent of all expenditure on drug, cost of antibiotic per patient care day and cost per antibiotic day was 3.84 Ethiopian Birr (ETB) ($0.40) and 6.29 ETB ($0.66) respectively. The correlation between infectious diseases diagnosed and antibiotic prescription shows significant variation. At outpatient departments alone an average number of antibiotic courses started was 2.7 at Gimbie Adventist Hospital and 7.6 for Nedjo Hospital. When overall antibiotic days prescribed and required was compared in both hospitals, there were 2.4 and 5 times more antibiotic days prescribed than were required for Gimbie and Nedjo Hospitals respectively. This suggests that the overuse of antibiotic is worse in the government hospital (Nedjo Hospital) than in the mission hospital (Gimbie Adventist Hospital). This study suggested that there was overuse of antibiotics in the West Wollega hospitals although further investigation is needed to identify its underlying causes and nature. It is recommended that the health personnel, the hospital management, the zonal and regional Health Bureau, the regulatory bodies and Non-Governmental Organizations (NGOs) work hand-in-hand to promote the rational use of antibiotics in this region so that the consequences and financial cost of antimicrobial resistance can be prevented.
- Full Text:
- Date Issued: 2010
- Authors: Banja, Wakweya Dugassa
- Date: 2010
- Subjects: Antibiotics , Bacterial diseases -- Chemotherapy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10141 , http://hdl.handle.net/10948/1263 , Antibiotics , Bacterial diseases -- Chemotherapy
- Description: In the last decades, there has been an escalating consumption of antibiotics with the number of antibiotic prescriptions increasing worldwide. Overuse or inappropriate use of antibiotics has resulted in a major increase in the development of multi-drug resistant pathogens. Antimicrobial resistance is one of the world’s most serious public health problems with great implication in terms of morbidity, mortality, and costs. To date, there has been no formal antibiotic use study conducted in the West Wollega zone of Ethiopia to assess antibiotic utilization. The objective of this study was to determine the pattern of antibiotic use in two hospitals in the West Wollega zone of Ethiopia, namely Gimbie Adventist Hospital and Nedjo Hospitals, using drug utilization metrics and the costs associated. In addition it was to assess the correlation between diagnosed infectious diseases and antibiotic prescriptions. This study was a cross-sectional, retrospective, descriptive review of antibiotic usage in the two hospitals in the year 2007. Prescriptions dispensed in the first month of each quarter of 2007 were reviewed. The number of prescriptions screened, antibiotic courses started, antibiotic days by specific agent and overall, the cost of individual and all antibiotics, the number and type of infectious diseases diagnosed were collected from which core drug use indicators were calculated. The correlation between infectious disease diagnosed and the antibiotic days prescribed were analyzed. A total of 18568 antibiotic and non-antibiotic prescriptions were reviewed retrospectively in the four months of the study period, 47 percent of which contained at least one antibiotic. The average number of antibiotics per prescription was 1.33 and 1.09 whilst the percentage of injectable antibiotics prescribed was 83.2 percent and 3.76 percent to outpatients and inpatients respectively. Antibiotics prescribed from the Essential Drug List (EDL) and List of Drugs for District Hospital (LDDH) were 63.0 percent, 74.8 percent, and 90.8 percent and 76.1 percent for outpatients and inpatients respectively. 98.6 percent of outpatient and 97.0 percent inpatient prescribed antibiotics were actually dispensed. Penicillins and quinolones were the most prescribed antibiotics in both inpatient and outpatient departments constituting 43.46 percent and 24.08 percent respectively. The antibiotic utilization ratio, incidence of outpatient antibiotic use, incidence of inpatient antibiotic use, the number of Defined Daily Doses (DDD)/1000inhabitants/year and DDD/100 Occupied Bed Days (OBD) for the zone was 0.16, 17.25, 23.56, 158.61, and 70 respectively. Antibiotic cost constituted 33.7 percent of all expenditure on drug, cost of antibiotic per patient care day and cost per antibiotic day was 3.84 Ethiopian Birr (ETB) ($0.40) and 6.29 ETB ($0.66) respectively. The correlation between infectious diseases diagnosed and antibiotic prescription shows significant variation. At outpatient departments alone an average number of antibiotic courses started was 2.7 at Gimbie Adventist Hospital and 7.6 for Nedjo Hospital. When overall antibiotic days prescribed and required was compared in both hospitals, there were 2.4 and 5 times more antibiotic days prescribed than were required for Gimbie and Nedjo Hospitals respectively. This suggests that the overuse of antibiotic is worse in the government hospital (Nedjo Hospital) than in the mission hospital (Gimbie Adventist Hospital). This study suggested that there was overuse of antibiotics in the West Wollega hospitals although further investigation is needed to identify its underlying causes and nature. It is recommended that the health personnel, the hospital management, the zonal and regional Health Bureau, the regulatory bodies and Non-Governmental Organizations (NGOs) work hand-in-hand to promote the rational use of antibiotics in this region so that the consequences and financial cost of antimicrobial resistance can be prevented.
- Full Text:
- Date Issued: 2010
Antimicrobial activity of selected Eastern Cape medical plants
- Authors: Mohlakoana, Keneuoe
- Date: 2010
- Subjects: Materia medica, Vegetable -- South Africa , Drug resistance in microorganisms -- South Africa , Anti-infective agents -- South Africa , Antibiotics
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10120 , http://hdl.handle.net/10948/1199 , Materia medica, Vegetable -- South Africa , Drug resistance in microorganisms -- South Africa , Anti-infective agents -- South Africa , Antibiotics
- Description: Bacterial resistance to antibiotics has been a great problem for many years. The degree of resistance and the speed with which resistance develops varies with different organisms and different drugs. Enzymes called β-lactamases are produced by bacteria and are one mechanism in which bacteria develop antimicrobial resistance. Gram-negative bacteria producing enzymes called ESBLs because of their wide substrate range are of a particular concern in nosocomial infections. In many countries people still use traditional medicine derived from plants as an alternative to the Western medicine due to increased cost of Western medicine and microbial resistance of antibiotic treatments. Biologically active compounds isolated from plants species are used in herbal medicine. Because of the high prevalence of the ESBLs and their increasing resistance to the antibiotics, this research study was done to test the antimicrobial activities of selected medicinal plants of the Eastern Cape; G. incanum, D. angustifolia and E. autumnalis which were traditionally used to treat various infections. The in vitro antimicrobial activity of three different extracts (acetone, methanol & distilled water) and the traditional preparations of the three plants were tested against the selected strains of ESBL-producing bacteria, non β-lactamase producers and the different fungal species. The extracts were screened against 26 Gram-positive bacterial strains, 53 Gram-negative bacterial strains and 15 fungal strains. The Gram-positive bacteria included strains from S. aureus, B. cereus and E. faecalis. The Gram-negative bacteria included strains from E. ii coli, E. cloacae, K. pneumoniae, P. aeruginosa and Acinetobacter spp. The fungal strains included 9 strains of Candida albicans and a single strain of each of the following opportunistic fungi, Mucor sp, Geotrichium sp, Penicillium sp, Fusarium sp and Rhizopus sp. The agar dilution assay was used for the antimicrobial screening of the plants extracts and for the determination of the MICs. The Ames test was performed for the determination of probable carcinogenicity of the extracts of G. incanum and D. angustifolia. The distilled water extracts followed by acetone extracts of the plants revealed the highest antimicrobial activity against the different microbial strains. The extracts of G. incanum followed by the extracts of D. angustifolia inhibited the highest number of microbial strains. The extracts of E. autumnalis did not show any antimicrobial activity against all the pathogens in this study. More of the Gram-positive bacteria were inhibited by the plant extracts. The lowest MIC was obtained with Gram-positive bacteria. The bacterial strains of E. faecalis and P. aeruginosa were not inhibited by any of the plants extracts in the agar dilution assay yet Acinetobacter species which are MDR were inhibited by the distilled water and methanol extracts of G. incanum. A single strain of Mucor sp was the only spore forming fungi that was inhibited by the distilled water extracts of G. incanum. None of the plants extracts showed any mutagenic effects on the TA100 S. typhimurium strains incorporated on the Ames test. Apart from revealing of new antimicrobial agents that may be used against resistant organisms, the proper use of antimicrobial agents should be recommended. The study has highlighted a need for further investigations on the properties of the medicinal plants used in this study.
- Full Text:
- Date Issued: 2010
- Authors: Mohlakoana, Keneuoe
- Date: 2010
- Subjects: Materia medica, Vegetable -- South Africa , Drug resistance in microorganisms -- South Africa , Anti-infective agents -- South Africa , Antibiotics
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10120 , http://hdl.handle.net/10948/1199 , Materia medica, Vegetable -- South Africa , Drug resistance in microorganisms -- South Africa , Anti-infective agents -- South Africa , Antibiotics
- Description: Bacterial resistance to antibiotics has been a great problem for many years. The degree of resistance and the speed with which resistance develops varies with different organisms and different drugs. Enzymes called β-lactamases are produced by bacteria and are one mechanism in which bacteria develop antimicrobial resistance. Gram-negative bacteria producing enzymes called ESBLs because of their wide substrate range are of a particular concern in nosocomial infections. In many countries people still use traditional medicine derived from plants as an alternative to the Western medicine due to increased cost of Western medicine and microbial resistance of antibiotic treatments. Biologically active compounds isolated from plants species are used in herbal medicine. Because of the high prevalence of the ESBLs and their increasing resistance to the antibiotics, this research study was done to test the antimicrobial activities of selected medicinal plants of the Eastern Cape; G. incanum, D. angustifolia and E. autumnalis which were traditionally used to treat various infections. The in vitro antimicrobial activity of three different extracts (acetone, methanol & distilled water) and the traditional preparations of the three plants were tested against the selected strains of ESBL-producing bacteria, non β-lactamase producers and the different fungal species. The extracts were screened against 26 Gram-positive bacterial strains, 53 Gram-negative bacterial strains and 15 fungal strains. The Gram-positive bacteria included strains from S. aureus, B. cereus and E. faecalis. The Gram-negative bacteria included strains from E. ii coli, E. cloacae, K. pneumoniae, P. aeruginosa and Acinetobacter spp. The fungal strains included 9 strains of Candida albicans and a single strain of each of the following opportunistic fungi, Mucor sp, Geotrichium sp, Penicillium sp, Fusarium sp and Rhizopus sp. The agar dilution assay was used for the antimicrobial screening of the plants extracts and for the determination of the MICs. The Ames test was performed for the determination of probable carcinogenicity of the extracts of G. incanum and D. angustifolia. The distilled water extracts followed by acetone extracts of the plants revealed the highest antimicrobial activity against the different microbial strains. The extracts of G. incanum followed by the extracts of D. angustifolia inhibited the highest number of microbial strains. The extracts of E. autumnalis did not show any antimicrobial activity against all the pathogens in this study. More of the Gram-positive bacteria were inhibited by the plant extracts. The lowest MIC was obtained with Gram-positive bacteria. The bacterial strains of E. faecalis and P. aeruginosa were not inhibited by any of the plants extracts in the agar dilution assay yet Acinetobacter species which are MDR were inhibited by the distilled water and methanol extracts of G. incanum. A single strain of Mucor sp was the only spore forming fungi that was inhibited by the distilled water extracts of G. incanum. None of the plants extracts showed any mutagenic effects on the TA100 S. typhimurium strains incorporated on the Ames test. Apart from revealing of new antimicrobial agents that may be used against resistant organisms, the proper use of antimicrobial agents should be recommended. The study has highlighted a need for further investigations on the properties of the medicinal plants used in this study.
- Full Text:
- Date Issued: 2010
Applicability of the REALM health literacy test to an English second-language South African population:
- Dowse, Roslind, Lecoko, Motlalepule L E, Ehlers, Martina S
- Authors: Dowse, Roslind , Lecoko, Motlalepule L E , Ehlers, Martina S
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156798 , vital:40051 , https://doi.org/10.1007/s11096-010-9392-y
- Description: Objective and setting. To investigate health literacy in an English second language population using the REALM test, to evaluate its appropriateness and to compare health literacy between four different education categories. Setting Primary healthcare clinics and participant homes in Grahamstown, South Africa.
- Full Text:
- Date Issued: 2010
- Authors: Dowse, Roslind , Lecoko, Motlalepule L E , Ehlers, Martina S
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156798 , vital:40051 , https://doi.org/10.1007/s11096-010-9392-y
- Description: Objective and setting. To investigate health literacy in an English second language population using the REALM test, to evaluate its appropriateness and to compare health literacy between four different education categories. Setting Primary healthcare clinics and participant homes in Grahamstown, South Africa.
- Full Text:
- Date Issued: 2010
Application of multiserver queueing to call centres
- Authors: Majakwara, Jacob
- Date: 2010
- Subjects: Call centers , ERLANG (Computer program language) , Queuing theory
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5578 , http://hdl.handle.net/10962/d1015461
- Description: The simplest and most widely used queueing model in call centres is the M/M/k system, sometimes referred to as Erlang-C. For many applications the model is an over-simplification. Erlang-C model ignores among other things busy signals, customer impatience and services that span multiple visits. Although the Erlang-C formula is easily implemented, it is not easy to obtain insight from its answers (for example, to find an approximate answer to questions such as "how many additional agents do I need if the arrival rate doubles?"). An approximation of the Erlang-C formula that gives structural insight into this type of question would be of use to better understand economies of scale in call centre operations. Erlang-C based predictions can also turn out highly inaccurate because of violations of underlying assumptions and these violations are not straightforward to model. For example, non-exponential service times lead one to the M/G/k queue which, in stark contrast to the M/M/k system, is difficult to analyse. This thesis deals mainly with the general M/GI/k model with abandonment. The arrival process conforms to a Poisson process, service durations are independent and identically distributed with a general distribution, there are k servers, and independent and identically distributed customer abandoning times with a general distribution. This thesis will endeavour to analyse call centres using M/GI/k model with abandonment and the data to be used will be simulated using EZSIM-software. The paper by Brown et al. [3] entitled "Statistical Analysis of a Telephone Call Centre: A Queueing-Science Perspective," will be the basis upon which this thesis is built.
- Full Text:
- Date Issued: 2010
- Authors: Majakwara, Jacob
- Date: 2010
- Subjects: Call centers , ERLANG (Computer program language) , Queuing theory
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5578 , http://hdl.handle.net/10962/d1015461
- Description: The simplest and most widely used queueing model in call centres is the M/M/k system, sometimes referred to as Erlang-C. For many applications the model is an over-simplification. Erlang-C model ignores among other things busy signals, customer impatience and services that span multiple visits. Although the Erlang-C formula is easily implemented, it is not easy to obtain insight from its answers (for example, to find an approximate answer to questions such as "how many additional agents do I need if the arrival rate doubles?"). An approximation of the Erlang-C formula that gives structural insight into this type of question would be of use to better understand economies of scale in call centre operations. Erlang-C based predictions can also turn out highly inaccurate because of violations of underlying assumptions and these violations are not straightforward to model. For example, non-exponential service times lead one to the M/G/k queue which, in stark contrast to the M/M/k system, is difficult to analyse. This thesis deals mainly with the general M/GI/k model with abandonment. The arrival process conforms to a Poisson process, service durations are independent and identically distributed with a general distribution, there are k servers, and independent and identically distributed customer abandoning times with a general distribution. This thesis will endeavour to analyse call centres using M/GI/k model with abandonment and the data to be used will be simulated using EZSIM-software. The paper by Brown et al. [3] entitled "Statistical Analysis of a Telephone Call Centre: A Queueing-Science Perspective," will be the basis upon which this thesis is built.
- Full Text:
- Date Issued: 2010
Application of Section 189 and Section 189A of the Labour Relations Act 66 of 1995 as amended
- Authors: Rune, Mawethu Siyabulela
- Date: 2010
- Subjects: Downsizing of organizations -- Law and legislation -- South Africa , Employees -- Dismissal of -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:10220 , http://hdl.handle.net/10948/1281 , Downsizing of organizations -- Law and legislation -- South Africa , Employees -- Dismissal of -- South Africa
- Description: Economies worldwide have become more integrated and competitive due to the phenomenon of globalisation and its antecedents, which are improved technological communication, the use of technology in production, ever improving management of skills as well as standards of education. Amongst the consequences have been changing demands and rising expectations in terms of employee remuneration, job security and conditions of work. This has at the same time been accompanied by employers expecting greater profit. Against this backdrop, this treatise seeks to interrogate and to explain the processes that should constitute fair, rational and justifiable employee dismissal for operational purposes. This is done bearing in mind the global economic crisis and its impact on employees. The treatise constitutes an attempt to carve a cushioning mechanism for employees in the midst of the global economic storm. We consider the inadequacies of common law principles. We also submit that section 189 in its present form and its application by courts do not provide for substantive fairness interrogation when dealing with dismissal for operational reasons. We explore the legislative framework, interpretation by leading academics as well as applications by courts of section 189A, which prescribes that if dismissal is based on operational reasons, consideration must not only be based on substantive and procedural fairness but also that proper consideration of alternatives must have been explored before dismissal is effected.
- Full Text:
- Date Issued: 2010
- Authors: Rune, Mawethu Siyabulela
- Date: 2010
- Subjects: Downsizing of organizations -- Law and legislation -- South Africa , Employees -- Dismissal of -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:10220 , http://hdl.handle.net/10948/1281 , Downsizing of organizations -- Law and legislation -- South Africa , Employees -- Dismissal of -- South Africa
- Description: Economies worldwide have become more integrated and competitive due to the phenomenon of globalisation and its antecedents, which are improved technological communication, the use of technology in production, ever improving management of skills as well as standards of education. Amongst the consequences have been changing demands and rising expectations in terms of employee remuneration, job security and conditions of work. This has at the same time been accompanied by employers expecting greater profit. Against this backdrop, this treatise seeks to interrogate and to explain the processes that should constitute fair, rational and justifiable employee dismissal for operational purposes. This is done bearing in mind the global economic crisis and its impact on employees. The treatise constitutes an attempt to carve a cushioning mechanism for employees in the midst of the global economic storm. We consider the inadequacies of common law principles. We also submit that section 189 in its present form and its application by courts do not provide for substantive fairness interrogation when dealing with dismissal for operational reasons. We explore the legislative framework, interpretation by leading academics as well as applications by courts of section 189A, which prescribes that if dismissal is based on operational reasons, consideration must not only be based on substantive and procedural fairness but also that proper consideration of alternatives must have been explored before dismissal is effected.
- Full Text:
- Date Issued: 2010
Application of the sustainable livelihoods framework to the analysis of the Provincial Growth and Development Plan of the Eastern Cape: a case study of the Massive Food Production Programme in Nkonkobe Municipality and Buffalo City Municipality
- Authors: Dirwayi, Tafadzwa P
- Date: 2010
- Subjects: Sustainable agriculture -- South Africa -- Eastern Cape , Sustainable development -- South Africa -- Eastern Cape , Poverty -- South Africa -- Eastern Cape , Rural poor -- South Africa -- Eastern Cape , Food supply -- South Africa -- Eastern Cape , Food security -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11159 , http://hdl.handle.net/10353/353 , Sustainable agriculture -- South Africa -- Eastern Cape , Sustainable development -- South Africa -- Eastern Cape , Poverty -- South Africa -- Eastern Cape , Rural poor -- South Africa -- Eastern Cape , Food supply -- South Africa -- Eastern Cape , Food security -- South Africa -- Eastern Cape
- Description: The Government of the Eastern Cape Province introduced the Massive Food Production programme, which is a cornerstone within the agrarian reform initiative of the Provincial Growth and Development Plan (PGDP). The programme has been going on for more than seven years, however little has been documented on its impact. The main objective of the study was to investigate the impact of the Massive Food Production Programme on the livelihoods in Nkonkobe Municipality. This study did not only investigate its impact on the participants but also assessed its impact on the recipient communities. Accordingly, the specific objectives of the study were to investigate the impact of the Massive Food Programme on the asset base of participants, the general livelihood activities, and the livelihood outcomes. Among other livelihood activities, the study made an in-depth investigation on the impact of the Massive Food Production Programme on maize crop production. This is because the Massive Food Production was aimed at maize crop production. Previous studies investigated on the indicators of success that can be used to measure the impact of this programme. After the wide-ranging evaluation of views, arguments and research findings, a model to measure impact of the programme was designed. The asset base improvement was used as the proxy of impact. Nine factors were selected from the principal component analysis of the many factors that were taken to affect participation. Three other dummy variables to proximate location, participation and group turnover were added to the regression model that was developed to measure impact. The DFID Sustainable Livelihood Framework was used to investigate the impact of the Massive Food Production Programme. This approach was used in both conceptualizing the study and the selection of variables. The DFID Sustainable Livelihood Approach was selected because unlike the CARE or UNDP Sustainable Livelihood models, it was designed for such purposes. Data collection was accomplished through observation, interviewing, and focus group discussions. The researcher also made use of project annual reports on change of livelihoods, baseline survey reports, project log frame, internal reports, work plans, budgets and mid-term evaluation reports as sources of secondary data. v The research findings were analysed using several analytical procedures, including the conventional descriptive statistics, principal components analysis, and linear regression analysis. The use of the different types of analysis was driven by the research questions under investigation and the theories on which they are based, and by the available data. The study revealed that to some extent the Massive Food Production Programme has managed to improve the asset base of the farmers. However, its impact on ensuring food security is still debatable. Findings of the study revealed that most of the participants and the non-participants communities experienced food shortages in the last season 2007/8 for at most three months. The study revealed that the highest agricultural income is from livestock sales. The varying locations showed the potential of livestock production. It is recommended that development agencies consider livestock production as an agricultural strategy with immense potential for enhancing sustaining rural livelihoods
- Full Text:
- Date Issued: 2010
- Authors: Dirwayi, Tafadzwa P
- Date: 2010
- Subjects: Sustainable agriculture -- South Africa -- Eastern Cape , Sustainable development -- South Africa -- Eastern Cape , Poverty -- South Africa -- Eastern Cape , Rural poor -- South Africa -- Eastern Cape , Food supply -- South Africa -- Eastern Cape , Food security -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11159 , http://hdl.handle.net/10353/353 , Sustainable agriculture -- South Africa -- Eastern Cape , Sustainable development -- South Africa -- Eastern Cape , Poverty -- South Africa -- Eastern Cape , Rural poor -- South Africa -- Eastern Cape , Food supply -- South Africa -- Eastern Cape , Food security -- South Africa -- Eastern Cape
- Description: The Government of the Eastern Cape Province introduced the Massive Food Production programme, which is a cornerstone within the agrarian reform initiative of the Provincial Growth and Development Plan (PGDP). The programme has been going on for more than seven years, however little has been documented on its impact. The main objective of the study was to investigate the impact of the Massive Food Production Programme on the livelihoods in Nkonkobe Municipality. This study did not only investigate its impact on the participants but also assessed its impact on the recipient communities. Accordingly, the specific objectives of the study were to investigate the impact of the Massive Food Programme on the asset base of participants, the general livelihood activities, and the livelihood outcomes. Among other livelihood activities, the study made an in-depth investigation on the impact of the Massive Food Production Programme on maize crop production. This is because the Massive Food Production was aimed at maize crop production. Previous studies investigated on the indicators of success that can be used to measure the impact of this programme. After the wide-ranging evaluation of views, arguments and research findings, a model to measure impact of the programme was designed. The asset base improvement was used as the proxy of impact. Nine factors were selected from the principal component analysis of the many factors that were taken to affect participation. Three other dummy variables to proximate location, participation and group turnover were added to the regression model that was developed to measure impact. The DFID Sustainable Livelihood Framework was used to investigate the impact of the Massive Food Production Programme. This approach was used in both conceptualizing the study and the selection of variables. The DFID Sustainable Livelihood Approach was selected because unlike the CARE or UNDP Sustainable Livelihood models, it was designed for such purposes. Data collection was accomplished through observation, interviewing, and focus group discussions. The researcher also made use of project annual reports on change of livelihoods, baseline survey reports, project log frame, internal reports, work plans, budgets and mid-term evaluation reports as sources of secondary data. v The research findings were analysed using several analytical procedures, including the conventional descriptive statistics, principal components analysis, and linear regression analysis. The use of the different types of analysis was driven by the research questions under investigation and the theories on which they are based, and by the available data. The study revealed that to some extent the Massive Food Production Programme has managed to improve the asset base of the farmers. However, its impact on ensuring food security is still debatable. Findings of the study revealed that most of the participants and the non-participants communities experienced food shortages in the last season 2007/8 for at most three months. The study revealed that the highest agricultural income is from livestock sales. The varying locations showed the potential of livestock production. It is recommended that development agencies consider livestock production as an agricultural strategy with immense potential for enhancing sustaining rural livelihoods
- Full Text:
- Date Issued: 2010
Applications of polymerized metal tetra-amino phthalocyanines towards hydrogen peroxide detection
- Mashazi, Philani N, Togo, Chumunorwa, Limson, Janice L, Nyokong, Tebello
- Authors: Mashazi, Philani N , Togo, Chumunorwa , Limson, Janice L , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261840 , vital:53451 , xlink:href="https://doi.org/10.1142/S1088424610001994"
- Description: This work reports the use of metallo tetra-amino phthalocyanines (MTAPc, M = Co and Mn) polymer thin films on gold and glassy carbon electrode surfaces for the detection and monitoring of hydrogen peroxide (H2O2). The polymer-modified electrodes were characterized using electrochemical and microscopic-based methods. Atomic force microscopy (AFM) was used to study the bare and polymer-modified ITO surfaces. The electrocatalytic reduction of H2O2 with glassy carbon polymer-modified electrodes gave higher current densities compared to their gold counterparts. The electroanalytical properties of H2O2 were obtained using a real-time calibration curve of the amperometric determination in pH 7.4 aqueous solution. The limits of detection (LoD) of the polymer-modified electrodes towards electroreduction of H2O2 were of the order of 10–7 M, with high sensitivity ranging from 6.0–15.4 mA.mM-1.cm-2.
- Full Text:
- Date Issued: 2010
- Authors: Mashazi, Philani N , Togo, Chumunorwa , Limson, Janice L , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261840 , vital:53451 , xlink:href="https://doi.org/10.1142/S1088424610001994"
- Description: This work reports the use of metallo tetra-amino phthalocyanines (MTAPc, M = Co and Mn) polymer thin films on gold and glassy carbon electrode surfaces for the detection and monitoring of hydrogen peroxide (H2O2). The polymer-modified electrodes were characterized using electrochemical and microscopic-based methods. Atomic force microscopy (AFM) was used to study the bare and polymer-modified ITO surfaces. The electrocatalytic reduction of H2O2 with glassy carbon polymer-modified electrodes gave higher current densities compared to their gold counterparts. The electroanalytical properties of H2O2 were obtained using a real-time calibration curve of the amperometric determination in pH 7.4 aqueous solution. The limits of detection (LoD) of the polymer-modified electrodes towards electroreduction of H2O2 were of the order of 10–7 M, with high sensitivity ranging from 6.0–15.4 mA.mM-1.cm-2.
- Full Text:
- Date Issued: 2010
Applying a lean engagement assessment tool to improve the probability of successful lean implementation at AB company
- Authors: Kleinhans, Carel Pretorious
- Date: 2010
- Subjects: Lean manufacturing , Engagement (Philosophy) , Preparedness
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8593 , http://hdl.handle.net/10948/1521 , Lean manufacturing , Engagement (Philosophy) , Preparedness
- Description: Competitiveness is crucial to achieving solid future national economics. A nation’s competitiveness reflects the extent to which it is able to provide increased prosperity to its citizens. Competitiveness can be defined to include the level of productivity of a country. This, in turn, sets the sustainability level of prosperity that can be achieved by an economy (Porter & Schwab, 2008). President Mbeki stated in the 2004 State of the Nation Address that “(South Africa) must continue to focus on the growth, development, and modernisation of the First Economy” (National Research Foundation, n.d.). The National Research Foundation (n.d.) claims that knowledge, innovation, and productivity, as well as optimal use of resources in the enterprise, are key to a competitive, sustainable growing economy. Firms involved in lean manufacturing do so to improve overall company performance in terms of productivity, efficiency, profitability and reducing costs. More than 90 per cent of these firms claim to be successful in achieving such goals. There is a clear association between the use of lean manufacturing and achieving higher productivity (Lucey, 2008a). Against this research and the claims made by the National Research Foundation it may be stated that lean manufacturing results will impact positively on an economy’s growth. AB Company will be evaluated in terms of the readiness and future sustainability of its lean transformation for the purposes of this study. It is anticipated that the results of this study will contribute toward reducing the risk of failure associated with a major lean transformation in the business.
- Full Text:
- Date Issued: 2010
- Authors: Kleinhans, Carel Pretorious
- Date: 2010
- Subjects: Lean manufacturing , Engagement (Philosophy) , Preparedness
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8593 , http://hdl.handle.net/10948/1521 , Lean manufacturing , Engagement (Philosophy) , Preparedness
- Description: Competitiveness is crucial to achieving solid future national economics. A nation’s competitiveness reflects the extent to which it is able to provide increased prosperity to its citizens. Competitiveness can be defined to include the level of productivity of a country. This, in turn, sets the sustainability level of prosperity that can be achieved by an economy (Porter & Schwab, 2008). President Mbeki stated in the 2004 State of the Nation Address that “(South Africa) must continue to focus on the growth, development, and modernisation of the First Economy” (National Research Foundation, n.d.). The National Research Foundation (n.d.) claims that knowledge, innovation, and productivity, as well as optimal use of resources in the enterprise, are key to a competitive, sustainable growing economy. Firms involved in lean manufacturing do so to improve overall company performance in terms of productivity, efficiency, profitability and reducing costs. More than 90 per cent of these firms claim to be successful in achieving such goals. There is a clear association between the use of lean manufacturing and achieving higher productivity (Lucey, 2008a). Against this research and the claims made by the National Research Foundation it may be stated that lean manufacturing results will impact positively on an economy’s growth. AB Company will be evaluated in terms of the readiness and future sustainability of its lean transformation for the purposes of this study. It is anticipated that the results of this study will contribute toward reducing the risk of failure associated with a major lean transformation in the business.
- Full Text:
- Date Issued: 2010
Art and Ethical Criticism, edited by Garry L. Hagberg
- Authors: Jones, Ward E
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275612 , vital:55063 , xlink:href="https://doi.org/10.1093/mind/fzq098"
- Description: Book Review: If there is a norm that a book’s title should give a reliable indication of its contents, Art and Ethical Criticism does not quite meet it. By my judgement, only seven of its twelve essays concern either the ethical criticism of art or the criticism of ethical positions within artworks.
- Full Text:
- Date Issued: 2010
- Authors: Jones, Ward E
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275612 , vital:55063 , xlink:href="https://doi.org/10.1093/mind/fzq098"
- Description: Book Review: If there is a norm that a book’s title should give a reliable indication of its contents, Art and Ethical Criticism does not quite meet it. By my judgement, only seven of its twelve essays concern either the ethical criticism of art or the criticism of ethical positions within artworks.
- Full Text:
- Date Issued: 2010
Arthropod Fauna of the UAE Vol. 3, A. van Harten (Ed.): book review
- Authors: Villet, Martin H
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451598 , vital:75062 , https://hdl.handle.net/10520/EJC32858
- Description: It has been a year since the second volume of the UAE Insect Project's Arthropod Fauna of the United Arab Emirates was published, and several more members of the team of over 160 scientists from 27 countries have visited the UAE. This has provided several of the chapters in the third volume of this series, which contains contributions from 51 taxonomists from 20 countries, including South Africa. Under the patronage of His Highness Sheikh Tahoon Bin Zayed Al Nahyan and the leadership of the editor, the series is settling down to a very high standard, especially in terms of its lavish illustrations, exquisite production and, of course, taxonomic rigour.
- Full Text:
- Date Issued: 2010
- Authors: Villet, Martin H
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451598 , vital:75062 , https://hdl.handle.net/10520/EJC32858
- Description: It has been a year since the second volume of the UAE Insect Project's Arthropod Fauna of the United Arab Emirates was published, and several more members of the team of over 160 scientists from 27 countries have visited the UAE. This has provided several of the chapters in the third volume of this series, which contains contributions from 51 taxonomists from 20 countries, including South Africa. Under the patronage of His Highness Sheikh Tahoon Bin Zayed Al Nahyan and the leadership of the editor, the series is settling down to a very high standard, especially in terms of its lavish illustrations, exquisite production and, of course, taxonomic rigour.
- Full Text:
- Date Issued: 2010
Artificial neural networks as simulators for behavioural evolution in evolutionary robotics
- Pretorius, Christiaan Johannes
- Authors: Pretorius, Christiaan Johannes
- Date: 2010
- Subjects: Neural networks (Computer science) , Robotics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10462 , http://hdl.handle.net/10948/1476 , Neural networks (Computer science) , Robotics
- Description: Robotic simulators for use in Evolutionary Robotics (ER) have certain challenges associated with the complexity of their construction and the accuracy of predictions made by these simulators. Such robotic simulators are often based on physics models, which have been shown to produce accurate results. However, the construction of physics-based simulators can be complex and time-consuming. Alternative simulation schemes construct robotic simulators from empirically-collected data. Such empirical simulators, however, also have associated challenges, such as that some of these simulators do not generalize well on the data from which they are constructed, as these models employ simple interpolation on said data. As a result of the identified challenges in existing robotic simulators for use in ER, this project investigates the potential use of Artificial Neural Networks, henceforth simply referred to as Neural Networks (NNs), as alternative robotic simulators. In contrast to physics models, NN-based simulators can be constructed without needing an explicit mathematical model of the system being modeled, which can simplify simulator development. Furthermore, the generalization capabilities of NNs suggest that NNs could generalize well on data from which these simulators are constructed. These generalization abilities of NNs, along with NNs’ noise tolerance, suggest that NNs could be well-suited to application in robotics simulation. Investigating whether NNs can be effectively used as robotic simulators in ER is thus the endeavour of this work. Since not much research has been done in employing NNs as robotic simulators, many aspects of the experimental framework on which this dissertation reports needed to be carefully decided upon. Two robot morphologies were selected on which the NN simulators created in this work were based, namely a differentially steered robot and an inverted pendulum robot. Motion tracking and robotic sensor logging were used to acquire data from which the NN simulators were constructed. Furthermore, custom code was written for almost all aspects of the study, namely data acquisition for NN training, the actual NN training process, the evolution of robotic controllers using the created NN simulators, as well as the onboard robotic implementations of evolved controllers. Experimental tests performed in order to determine ideal topologies for each of the NN simulators developed in this study indicated that different NN topologies can lead to large differences in training accuracy. After performing these tests, the training accuracy of the created simulators was analyzed. This analysis showed that the NN simulators generally trained well and could generalize well on data not presented during simulator construction. In order to validate the feasibility of the created NN simulators in the ER process, these simulators were subsequently used to evolve controllers in simulation, similar to controllers developed in related studies. Encouraging results were obtained, with the newly-evolved controllers allowing real-world experimental robots to exhibit obstacle avoidance and light-approaching behaviour with a reasonable degree of success. The created NN simulators furthermore allowed for the successful evolution of a complex inverted pendulum stabilization controller in simulation. It was thus clearly established that NN-based robotic simulators can be successfully employed as alternative simulation schemes in the ER process.
- Full Text:
- Date Issued: 2010
- Authors: Pretorius, Christiaan Johannes
- Date: 2010
- Subjects: Neural networks (Computer science) , Robotics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10462 , http://hdl.handle.net/10948/1476 , Neural networks (Computer science) , Robotics
- Description: Robotic simulators for use in Evolutionary Robotics (ER) have certain challenges associated with the complexity of their construction and the accuracy of predictions made by these simulators. Such robotic simulators are often based on physics models, which have been shown to produce accurate results. However, the construction of physics-based simulators can be complex and time-consuming. Alternative simulation schemes construct robotic simulators from empirically-collected data. Such empirical simulators, however, also have associated challenges, such as that some of these simulators do not generalize well on the data from which they are constructed, as these models employ simple interpolation on said data. As a result of the identified challenges in existing robotic simulators for use in ER, this project investigates the potential use of Artificial Neural Networks, henceforth simply referred to as Neural Networks (NNs), as alternative robotic simulators. In contrast to physics models, NN-based simulators can be constructed without needing an explicit mathematical model of the system being modeled, which can simplify simulator development. Furthermore, the generalization capabilities of NNs suggest that NNs could generalize well on data from which these simulators are constructed. These generalization abilities of NNs, along with NNs’ noise tolerance, suggest that NNs could be well-suited to application in robotics simulation. Investigating whether NNs can be effectively used as robotic simulators in ER is thus the endeavour of this work. Since not much research has been done in employing NNs as robotic simulators, many aspects of the experimental framework on which this dissertation reports needed to be carefully decided upon. Two robot morphologies were selected on which the NN simulators created in this work were based, namely a differentially steered robot and an inverted pendulum robot. Motion tracking and robotic sensor logging were used to acquire data from which the NN simulators were constructed. Furthermore, custom code was written for almost all aspects of the study, namely data acquisition for NN training, the actual NN training process, the evolution of robotic controllers using the created NN simulators, as well as the onboard robotic implementations of evolved controllers. Experimental tests performed in order to determine ideal topologies for each of the NN simulators developed in this study indicated that different NN topologies can lead to large differences in training accuracy. After performing these tests, the training accuracy of the created simulators was analyzed. This analysis showed that the NN simulators generally trained well and could generalize well on data not presented during simulator construction. In order to validate the feasibility of the created NN simulators in the ER process, these simulators were subsequently used to evolve controllers in simulation, similar to controllers developed in related studies. Encouraging results were obtained, with the newly-evolved controllers allowing real-world experimental robots to exhibit obstacle avoidance and light-approaching behaviour with a reasonable degree of success. The created NN simulators furthermore allowed for the successful evolution of a complex inverted pendulum stabilization controller in simulation. It was thus clearly established that NN-based robotic simulators can be successfully employed as alternative simulation schemes in the ER process.
- Full Text:
- Date Issued: 2010
Aspects of the biology and fisheries of an economically important sparid Dentex macrophthalmus (Bloch 1791) in the Namibe province, Angola
- Potts, Warren M, Inácio, L A, Santos, Carmen V D, Richardson, Timothy J, Sauer, Warwick H H
- Authors: Potts, Warren M , Inácio, L A , Santos, Carmen V D , Richardson, Timothy J , Sauer, Warwick H H
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123096 , vital:35405 , https://doi.org/10.2989/1814232X.2010.538160
- Description: Dentex macrophthalmus is a small, commercially important sparid fish that is abundant in the deeper waters (range 50–500 m) of the Mediterranean Sea (Trunov 1970), the North-West African shelf (Goode and Bean 1896, Fowler 1936), including the Cape Verde and Canary Islands, and the south-eastern Atlantic from the Equator to just south of Lüderitz (27°40′ S) (Trunov 1970). Because of its high abundance, it is of considerable economic importance and is captured in large numbers in both artisanal and commercial fisheries in many countries. Although it is the most important artisanal species along the entire Angolan coast, it is most abundant in the southern region (Kilongo et al. 2007). Despite its economic importance in Angola and elsewhere, relatively little is known on its abundance, fisheries and biology.
- Full Text:
- Date Issued: 2010
- Authors: Potts, Warren M , Inácio, L A , Santos, Carmen V D , Richardson, Timothy J , Sauer, Warwick H H
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123096 , vital:35405 , https://doi.org/10.2989/1814232X.2010.538160
- Description: Dentex macrophthalmus is a small, commercially important sparid fish that is abundant in the deeper waters (range 50–500 m) of the Mediterranean Sea (Trunov 1970), the North-West African shelf (Goode and Bean 1896, Fowler 1936), including the Cape Verde and Canary Islands, and the south-eastern Atlantic from the Equator to just south of Lüderitz (27°40′ S) (Trunov 1970). Because of its high abundance, it is of considerable economic importance and is captured in large numbers in both artisanal and commercial fisheries in many countries. Although it is the most important artisanal species along the entire Angolan coast, it is most abundant in the southern region (Kilongo et al. 2007). Despite its economic importance in Angola and elsewhere, relatively little is known on its abundance, fisheries and biology.
- Full Text:
- Date Issued: 2010
Aspects of the reproductive biology of monkfish Lophius vomerinus off Namibia
- Maartens, Lima, Booth, Anthony J
- Authors: Maartens, Lima , Booth, Anthony J
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123831 , vital:35504 , https://doi.10.2989/18142320509504090
- Description: Aspects of the reproductive biology of monkfish Lophius vomerinus are described from material collected during hake Merluccius spp. biomass surveys and from commercial monkfish and sole Austroglossus microlepis vessels between January 1996 and June 2000 off Namibia at depths between 97m and 686m. Length-at-50% sexual maturity for males and females were estimated at 39.9cm and 58.2cm respectively, males maturing faster than females. The adult sex ratio of fish >50cm total length was strongly biased towards females. There was reproductive activity throughout the year, peaking slightly between autumn and spring.
- Full Text:
- Date Issued: 2010
- Authors: Maartens, Lima , Booth, Anthony J
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123831 , vital:35504 , https://doi.10.2989/18142320509504090
- Description: Aspects of the reproductive biology of monkfish Lophius vomerinus are described from material collected during hake Merluccius spp. biomass surveys and from commercial monkfish and sole Austroglossus microlepis vessels between January 1996 and June 2000 off Namibia at depths between 97m and 686m. Length-at-50% sexual maturity for males and females were estimated at 39.9cm and 58.2cm respectively, males maturing faster than females. The adult sex ratio of fish >50cm total length was strongly biased towards females. There was reproductive activity throughout the year, peaking slightly between autumn and spring.
- Full Text:
- Date Issued: 2010
Assessing a marketing strategy for an engineering consulting company
- Authors: Maliti, Mbulelo Bruce
- Date: 2010
- Subjects: Construction industry -- Customer services -- Marketing , Consulting engineers -- Customer services -- South Africa , Design services -- Marketing , Project management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8626 , http://hdl.handle.net/10948/1489 , Construction industry -- Customer services -- Marketing , Consulting engineers -- Customer services -- South Africa , Design services -- Marketing , Project management
- Description: The engineering consulting industry in South Africa witnessed an overwhelming growth before the 2010 Fifa World Cup. The country had a lot of infrastructural development that needed the services of consulting engineers. A lot of people saw the challenge as a business opportunity and started their own consulting engineering companies. The demand for consulting engineering services was high before the 2010 Fifa World Cup; this changed after the completion of projects that were due for the world cup and some had to close or retrench staff due to scarcity of projects. The completion of 2010 Fifa World Cup projects is not the only challenge faced by the engineering consulting sector; government policies such tendering and procurement procedures that do not acknowledge performance, lack of funding etc. It is therefore important that companies look for better ways of gaining competitiveness in order to get more projects. These companies must not only rely on government projects but do marketing on the private sector as well. The purpose of the research is to assess and develop a marketing strategy for Company X Consulting engineers. A literature study on most successful marketing strategies employed by other service oriented companies was conducted. The literature study also comprised of the perception of marketing amongst consulting engineering companies. From the literature study mentioned above; questionnaires were drawn towards the development of a marketing strategy for Company X consulting engineers. The findings of the questionnaires were analysed and recommendation were made for the development of a marketing strategy for Company X.
- Full Text:
- Date Issued: 2010
- Authors: Maliti, Mbulelo Bruce
- Date: 2010
- Subjects: Construction industry -- Customer services -- Marketing , Consulting engineers -- Customer services -- South Africa , Design services -- Marketing , Project management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8626 , http://hdl.handle.net/10948/1489 , Construction industry -- Customer services -- Marketing , Consulting engineers -- Customer services -- South Africa , Design services -- Marketing , Project management
- Description: The engineering consulting industry in South Africa witnessed an overwhelming growth before the 2010 Fifa World Cup. The country had a lot of infrastructural development that needed the services of consulting engineers. A lot of people saw the challenge as a business opportunity and started their own consulting engineering companies. The demand for consulting engineering services was high before the 2010 Fifa World Cup; this changed after the completion of projects that were due for the world cup and some had to close or retrench staff due to scarcity of projects. The completion of 2010 Fifa World Cup projects is not the only challenge faced by the engineering consulting sector; government policies such tendering and procurement procedures that do not acknowledge performance, lack of funding etc. It is therefore important that companies look for better ways of gaining competitiveness in order to get more projects. These companies must not only rely on government projects but do marketing on the private sector as well. The purpose of the research is to assess and develop a marketing strategy for Company X Consulting engineers. A literature study on most successful marketing strategies employed by other service oriented companies was conducted. The literature study also comprised of the perception of marketing amongst consulting engineering companies. From the literature study mentioned above; questionnaires were drawn towards the development of a marketing strategy for Company X consulting engineers. The findings of the questionnaires were analysed and recommendation were made for the development of a marketing strategy for Company X.
- Full Text:
- Date Issued: 2010
Assessing challenges of corruption in the Eastern Cape Department of Education
- Authors: Basopu, Price Mike
- Date: 2010
- Subjects: Corruption -- South Africa -- Eastern Cape , Local government -- South Africa -- Eastern Cape , Education, Higher -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: vital:11618 , http://hdl.handle.net/10353/383 , Corruption -- South Africa -- Eastern Cape , Local government -- South Africa -- Eastern Cape , Education, Higher -- South Africa -- Eastern Cape
- Description: In the new dispensation, there are many challenges, especially concerning corruption. In this regard, the Eastern Cape is viewed as the most affected province, with the Department of Education identified as culprit number one engaging in corrupt activities. There are a number of contributing factors, as attributed in the study, but most prevalent among these is the vastness of the department, with fewer personnel and less capacity. Challenges of corruption in the Department of Education are perpetrated mainly by the civil servants. This study, researched the challenges of corruption in the Department of Education in the Eastern Cape, in particular by focusing on both the achievements and the limitations that have been experienced; and indeed, there are still numerous issues to be addressed and accomplished. The research, therefore, has been significant in that it touched on critical issues, such as, the public sector in general, which is corrupt. Misappropriation of public resources and corruption immersed the nation, as a whole, into a greater challenge rather than focusing on service delivery issues. There are situations, within the department, where the majority of senior officials, who may be in possession of valuable information, are always under suspension. In all the financial years the Department of Education existed, it always obtained disclaimer or adverse reports from the Office of Auditor-General (AG), despite numerous attempts and interventions by the AG‟s office and the Provincial Treasury to rectify the situation. There are also serious challenges of leadership crises in the Department of Education, both administratively and politically. During the research, that is, between the 2008 and 2010 financial years, there has been no permanent Head of Department; people were only acting in the capacity. vi Even those seconded from national education, could not finish the designated term, because of pressure mainly from the unions.
- Full Text:
- Date Issued: 2010
- Authors: Basopu, Price Mike
- Date: 2010
- Subjects: Corruption -- South Africa -- Eastern Cape , Local government -- South Africa -- Eastern Cape , Education, Higher -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: vital:11618 , http://hdl.handle.net/10353/383 , Corruption -- South Africa -- Eastern Cape , Local government -- South Africa -- Eastern Cape , Education, Higher -- South Africa -- Eastern Cape
- Description: In the new dispensation, there are many challenges, especially concerning corruption. In this regard, the Eastern Cape is viewed as the most affected province, with the Department of Education identified as culprit number one engaging in corrupt activities. There are a number of contributing factors, as attributed in the study, but most prevalent among these is the vastness of the department, with fewer personnel and less capacity. Challenges of corruption in the Department of Education are perpetrated mainly by the civil servants. This study, researched the challenges of corruption in the Department of Education in the Eastern Cape, in particular by focusing on both the achievements and the limitations that have been experienced; and indeed, there are still numerous issues to be addressed and accomplished. The research, therefore, has been significant in that it touched on critical issues, such as, the public sector in general, which is corrupt. Misappropriation of public resources and corruption immersed the nation, as a whole, into a greater challenge rather than focusing on service delivery issues. There are situations, within the department, where the majority of senior officials, who may be in possession of valuable information, are always under suspension. In all the financial years the Department of Education existed, it always obtained disclaimer or adverse reports from the Office of Auditor-General (AG), despite numerous attempts and interventions by the AG‟s office and the Provincial Treasury to rectify the situation. There are also serious challenges of leadership crises in the Department of Education, both administratively and politically. During the research, that is, between the 2008 and 2010 financial years, there has been no permanent Head of Department; people were only acting in the capacity. vi Even those seconded from national education, could not finish the designated term, because of pressure mainly from the unions.
- Full Text:
- Date Issued: 2010
Assessing the diet of the Cape leopard (panthera pardus) in the Cederberg and Gamka mountains, South Africa
- Authors: Rautenbach, Therèsè
- Date: 2010
- Subjects: Leopard -- South Africa , Animal feeding -- South Africa , Predation (Biology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10699 , http://hdl.handle.net/10948/1078 , Leopard -- South Africa , Animal feeding -- South Africa , Predation (Biology)
- Description: As limited prey availability and persecution by humans in response to livestock predation are key conservation concerns for the Cape leopard (Martins & Martins 2006), the present study aimed to provide more information regarding their feeding habits. The first objective was to determine whether the Cape leopard was subject to a change in their prey base and how they responded to the change. This was established by comparison of their current diet in the Cederberg and Gamka Mountains, determined by using scat analysis techniques, with a previous dietary assessment (Norton et al. 1986). The second aim was to provide a preliminary assessment of the prey preference of the Cape leopard and examine the utility of camera trap surveys to determine leopard prey preference. Leopard diet in the Cederberg and Gamka Mountains consisted largely of small- (1-10 kg) and medium-sized (10-40 kg) mammals; rock hyraxes (Procavia capensis) and klipspringers (Oreotragus oreotragus) were key prey items. In terms of regional variation in leopard diet, there was a significant difference in the average weight of prey utilized in the Cederberg and Gamka Mountains. Despite the importance of prey availability of suitable size, their flexibility in terms of prey size utilization reflected their ability to switch to smaller prey to fulfil their dietary requirements, when prey is limited. The study suggested a dietary shift, with significant variation in prey species utilization in both regions. The shift did not appear to be in response to prey scarcity, but rather a reduction in key prey species, particularly the rock hyrax. The shift involved an increase in the number of species utilized, and only a very small increase in livestock predation in both areas. There was however no significant variation in prey size category utilization. This demonstrated their dietary flexibility, as well as the importance of suitable prey sizes rather than the presence of specific prey species to fulfil their dietary requirements. The camera trap survey revealed a strong correlation between the number of camera trap days and the number of photographs taken of identifiable species. Variation of this correlation between different habitats supported the notion that individual images are a better unit to determine sampling efficiency than trap days. The camera trap survey also showed that small rodent availability was underestimated by camera trap surveillance, which resulted in poor prey preference estimation. It was therefore suggested that camera trap surveys be restricted to the surveillance of larger prey species (> 1 kg). By excluding small rodents from the analysis, prey preference could be estimated for other species and prey size categories. Small- and medium-sized mammals were significantly preferred, whereas large mammals were significantly avoided by the Cape leopard.
- Full Text:
- Date Issued: 2010
- Authors: Rautenbach, Therèsè
- Date: 2010
- Subjects: Leopard -- South Africa , Animal feeding -- South Africa , Predation (Biology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10699 , http://hdl.handle.net/10948/1078 , Leopard -- South Africa , Animal feeding -- South Africa , Predation (Biology)
- Description: As limited prey availability and persecution by humans in response to livestock predation are key conservation concerns for the Cape leopard (Martins & Martins 2006), the present study aimed to provide more information regarding their feeding habits. The first objective was to determine whether the Cape leopard was subject to a change in their prey base and how they responded to the change. This was established by comparison of their current diet in the Cederberg and Gamka Mountains, determined by using scat analysis techniques, with a previous dietary assessment (Norton et al. 1986). The second aim was to provide a preliminary assessment of the prey preference of the Cape leopard and examine the utility of camera trap surveys to determine leopard prey preference. Leopard diet in the Cederberg and Gamka Mountains consisted largely of small- (1-10 kg) and medium-sized (10-40 kg) mammals; rock hyraxes (Procavia capensis) and klipspringers (Oreotragus oreotragus) were key prey items. In terms of regional variation in leopard diet, there was a significant difference in the average weight of prey utilized in the Cederberg and Gamka Mountains. Despite the importance of prey availability of suitable size, their flexibility in terms of prey size utilization reflected their ability to switch to smaller prey to fulfil their dietary requirements, when prey is limited. The study suggested a dietary shift, with significant variation in prey species utilization in both regions. The shift did not appear to be in response to prey scarcity, but rather a reduction in key prey species, particularly the rock hyrax. The shift involved an increase in the number of species utilized, and only a very small increase in livestock predation in both areas. There was however no significant variation in prey size category utilization. This demonstrated their dietary flexibility, as well as the importance of suitable prey sizes rather than the presence of specific prey species to fulfil their dietary requirements. The camera trap survey revealed a strong correlation between the number of camera trap days and the number of photographs taken of identifiable species. Variation of this correlation between different habitats supported the notion that individual images are a better unit to determine sampling efficiency than trap days. The camera trap survey also showed that small rodent availability was underestimated by camera trap surveillance, which resulted in poor prey preference estimation. It was therefore suggested that camera trap surveys be restricted to the surveillance of larger prey species (> 1 kg). By excluding small rodents from the analysis, prey preference could be estimated for other species and prey size categories. Small- and medium-sized mammals were significantly preferred, whereas large mammals were significantly avoided by the Cape leopard.
- Full Text:
- Date Issued: 2010
Assessment of antibiotic production by some marine actinomycetes belonging to the genera norcadia, saccharopolyspora and kibdellosporangium.
- Koba, Siziwe (https://orcid.org/0000-0002-6761-6403)
- Authors: Koba, Siziwe (https://orcid.org/0000-0002-6761-6403)
- Date: 2010
- Subjects: Actinobacteria , Bacteria , Actinomycetales
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/25811 , vital:64488
- Description: Antibacterial potency of the extracts of the three marine actinomycetes strains which were isolated in the Nahoon Beach and tentatively identified as the genera Norcadia, Kibdellosporingium and Saccharopolyspora were investigated in this study against a panel of referenced, environmental and clinical bacterial strains. The ethyl acetate extracts of these marine actinomycetes were screened for activity against 32 bacterial isolates. Out of the 32 organisms, 10 were susceptible to one or all the extracts used. Antibacterial activity was mainly observed against Gram-negative organisms with Minimum inhibitory concentration (MIC) values ranging from 0.078 mg/ml to >10mg/ml. The killing rates of the active extracts were also elucidated using standard procedures. The two extracts NO64 and NO53 showed rapid bactericidal activity against B. pumilus ATCC 14884 and Serratia marcens with a 3Log10 reduction in counts within 6 hours at 3.75 mg/ml and 5 mg/ml respectively. In conclusion, the ethyl acetate extract of these marine actinomycetes strains possess strong bactericidal and bacteriostatic activities against Gram negative organisms and can be therapeutically useful in the treatment of bacterial infections which are mainly caused by Gram negative bacteria. , Thesis (MA) -- Faculty of Science and Agriculture, 2010
- Full Text:
- Date Issued: 2010
- Authors: Koba, Siziwe (https://orcid.org/0000-0002-6761-6403)
- Date: 2010
- Subjects: Actinobacteria , Bacteria , Actinomycetales
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/25811 , vital:64488
- Description: Antibacterial potency of the extracts of the three marine actinomycetes strains which were isolated in the Nahoon Beach and tentatively identified as the genera Norcadia, Kibdellosporingium and Saccharopolyspora were investigated in this study against a panel of referenced, environmental and clinical bacterial strains. The ethyl acetate extracts of these marine actinomycetes were screened for activity against 32 bacterial isolates. Out of the 32 organisms, 10 were susceptible to one or all the extracts used. Antibacterial activity was mainly observed against Gram-negative organisms with Minimum inhibitory concentration (MIC) values ranging from 0.078 mg/ml to >10mg/ml. The killing rates of the active extracts were also elucidated using standard procedures. The two extracts NO64 and NO53 showed rapid bactericidal activity against B. pumilus ATCC 14884 and Serratia marcens with a 3Log10 reduction in counts within 6 hours at 3.75 mg/ml and 5 mg/ml respectively. In conclusion, the ethyl acetate extract of these marine actinomycetes strains possess strong bactericidal and bacteriostatic activities against Gram negative organisms and can be therapeutically useful in the treatment of bacterial infections which are mainly caused by Gram negative bacteria. , Thesis (MA) -- Faculty of Science and Agriculture, 2010
- Full Text:
- Date Issued: 2010