The effect of grain and soya bean-based diets on chicken production, some egg quality traits, and the potential for allergen carryover to eggs and meat
- Authors: Dokora, Adia-En-Michelle
- Date: 2015
- Subjects: Chickens -- Nutrition Chickens --Feeding and feeds Meat -- Quality
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2946 , vital:28192
- Description: This study determined the effect of maize-, whole wheat-, soya bean-based-diets on the growth performance, egg quality and dressing percentage of chickens, as well as the potential for soy and gluten allergen carryover to eggs and meat from chickens. Twenty 36-week-old Lorham White (LW) hens were divided into two groups and kept in individual cages until they reached 39-weeks of age, with water and feed supplied ad libitum. Ten LW hens were fed a maize/soya bean-based diet (T1) and the other ten birds were fed a maize/soya bean-based diet with a 15 percent whole wheat inclusion (T2) for a period of four weeks, with weekly individual hen weights and group feed consumption figures being recorded. After a two-week diet adaptation period, six eggs per treatment group were collected every second day from the LW hens’ to measure egg quality traits. Every third day, over a 29-day period, six eggs per treatment were collected and analysed for the presence of soy, gluten and gluten-derived peptides using allergen specific enzyme linked immunosorbent assays (ELISA) kits. For the broiler trial, a total of 160 Ross 308 mixed sex day old chicks were used in a completely randomized design. Two dietary treatments were assigned to eight cages (replicate) per treatment, with ten birds per cage. The Ross 308 broiler feeding programme consisted of three phases, starter (day 1 to day 10), grower (day 11 to day 20) and finisher (day 21 to day 28). At the beginning of the trial all chicks were fed T1 which contained a maize/soya bean-based diet for a period of 10 days and then eight cages with 10 birds per cage were randomly selected and fed the T2 diet, which contained a maize/soya bean-based diet with a 15 percent whole wheat inclusion, until they reached 28 days of age. Weekly live weights, feed intake, average daily gain and the average daily feed intake were recorded and calculated. At the end of the grower (day 21) and finisher phase (day 28), one broiler bird was selected per cage to have eight (8) birds per treatment and 16 birds per phase that were slaughtered and breast meat samples were analysed in duplicate for the presence of soy and gluten allergens using ELISA kits. The dressing percentage of hot carcasses was also determined at the end of the finisher phase on eight birds per treatment. For LW hens, live weight (LW) at 39 weeks of age, the average daily feed intake (ADFI) and weekly feed intakes (FI) were significantly different (P < 0.05) between treatments with birds on T2 recording higher gains. As birds age in weeks increased, significant differences (P < 0.05) in live weight values were recorded. Egg quality traits measured (shell weight, yolk weight, albumen weight, albumen height and Haugh units) were significantly different (P < 0.05) between treatments, with eggs from hens receiving T1 recording higher mean values. As hens got older, the colour of egg yolk improved, producing eggs with higher b* (yellowness) values and lower L* (lightness) and a* (redness) mean values. The Haugh unit, significantly improved (P < 0.05) as the hens got older, signifying better quality of eggs. For the broiler birds, growth traits measured indicated that there were no significant differences (P > 0.05) in live weight (LW), average daily feed intake (ADFI), weekly feed intake (FI), feed conversion ratio (FCR), cumulative feed intake (CFI) and cumulative gain (CG) between treatments. No significant differences (P > 0.05) between dressing percentage of broilers from the two treatments were observed. As birds grew, significant differences (P < 0.05) in LW, FI, AFI, FCR, and CFI, over a four-week period were recorded. Results of the allergen analyses indicated that soy and gluten allergens were not carried over from feed into eggs and meat of chickens fed a maize/soya bean-based diet and a maize/soya bean-based with a 15 percent whole wheat inclusion, respectively. In conclusion, a maize/soya bean-based diet and maize/soya bean-based diet with a 15 percent whole wheat inclusion that contained soy and gluten allergens, are feed sources that promote and stimulate 36-week-old LW hen and Ross 308 chicken growth.
- Full Text:
- Date Issued: 2015
- Authors: Dokora, Adia-En-Michelle
- Date: 2015
- Subjects: Chickens -- Nutrition Chickens --Feeding and feeds Meat -- Quality
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2946 , vital:28192
- Description: This study determined the effect of maize-, whole wheat-, soya bean-based-diets on the growth performance, egg quality and dressing percentage of chickens, as well as the potential for soy and gluten allergen carryover to eggs and meat from chickens. Twenty 36-week-old Lorham White (LW) hens were divided into two groups and kept in individual cages until they reached 39-weeks of age, with water and feed supplied ad libitum. Ten LW hens were fed a maize/soya bean-based diet (T1) and the other ten birds were fed a maize/soya bean-based diet with a 15 percent whole wheat inclusion (T2) for a period of four weeks, with weekly individual hen weights and group feed consumption figures being recorded. After a two-week diet adaptation period, six eggs per treatment group were collected every second day from the LW hens’ to measure egg quality traits. Every third day, over a 29-day period, six eggs per treatment were collected and analysed for the presence of soy, gluten and gluten-derived peptides using allergen specific enzyme linked immunosorbent assays (ELISA) kits. For the broiler trial, a total of 160 Ross 308 mixed sex day old chicks were used in a completely randomized design. Two dietary treatments were assigned to eight cages (replicate) per treatment, with ten birds per cage. The Ross 308 broiler feeding programme consisted of three phases, starter (day 1 to day 10), grower (day 11 to day 20) and finisher (day 21 to day 28). At the beginning of the trial all chicks were fed T1 which contained a maize/soya bean-based diet for a period of 10 days and then eight cages with 10 birds per cage were randomly selected and fed the T2 diet, which contained a maize/soya bean-based diet with a 15 percent whole wheat inclusion, until they reached 28 days of age. Weekly live weights, feed intake, average daily gain and the average daily feed intake were recorded and calculated. At the end of the grower (day 21) and finisher phase (day 28), one broiler bird was selected per cage to have eight (8) birds per treatment and 16 birds per phase that were slaughtered and breast meat samples were analysed in duplicate for the presence of soy and gluten allergens using ELISA kits. The dressing percentage of hot carcasses was also determined at the end of the finisher phase on eight birds per treatment. For LW hens, live weight (LW) at 39 weeks of age, the average daily feed intake (ADFI) and weekly feed intakes (FI) were significantly different (P < 0.05) between treatments with birds on T2 recording higher gains. As birds age in weeks increased, significant differences (P < 0.05) in live weight values were recorded. Egg quality traits measured (shell weight, yolk weight, albumen weight, albumen height and Haugh units) were significantly different (P < 0.05) between treatments, with eggs from hens receiving T1 recording higher mean values. As hens got older, the colour of egg yolk improved, producing eggs with higher b* (yellowness) values and lower L* (lightness) and a* (redness) mean values. The Haugh unit, significantly improved (P < 0.05) as the hens got older, signifying better quality of eggs. For the broiler birds, growth traits measured indicated that there were no significant differences (P > 0.05) in live weight (LW), average daily feed intake (ADFI), weekly feed intake (FI), feed conversion ratio (FCR), cumulative feed intake (CFI) and cumulative gain (CG) between treatments. No significant differences (P > 0.05) between dressing percentage of broilers from the two treatments were observed. As birds grew, significant differences (P < 0.05) in LW, FI, AFI, FCR, and CFI, over a four-week period were recorded. Results of the allergen analyses indicated that soy and gluten allergens were not carried over from feed into eggs and meat of chickens fed a maize/soya bean-based diet and a maize/soya bean-based with a 15 percent whole wheat inclusion, respectively. In conclusion, a maize/soya bean-based diet and maize/soya bean-based diet with a 15 percent whole wheat inclusion that contained soy and gluten allergens, are feed sources that promote and stimulate 36-week-old LW hen and Ross 308 chicken growth.
- Full Text:
- Date Issued: 2015
The effectiveness of arbitration practice relative to South African construction
- Authors: Bvumbwe, Chikumbutso
- Date: 2015
- Subjects: Arbitration, Industrial -- South Africa Dispute resolution (Law) -- South Africa , Construction industry -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47981 , vital:40460
- Description: The study investigated the arbitration practice relative to the South African construction industry. Most of the construction contracts include an arbitration clause in the contract document as an instrument to be used for resolving disputes. The aim is to resolve disputes between the parties with minimum costs and within a reasonable period. Some parties opt to involve legal counsel in the process which has a potential of affecting time and cost. The literature review focuses on arbitration, in the construction industry, with a particular focus on how effective the methods are in terms of cost, time and the relationship between the disputing parties, the impact of using legal counsel during the arbitration process versus not involving legal counsel, the arbitration clause not specifying when to declare a dispute, and the perception of construction professionals on arbitration. The study was based on closed-ended questionnaires distributed among senior construction professionals including, architects, quantity surveyors, construction managers, project managers and practising attorneys. 61 respondents completed the questionnaire. The respondents were asked to comment on the effectiveness of alternative dispute resolution, cost, time, causes of disputes, and impacts of disputes. The cost of arbitration seems to escalate as a result of legal counsel being involved during the arbitration procedures. The time factor also seems to be prolonged. A notable finding indicates that the arbitration clause in the contract document should specify when to declare the dispute. The survey was conducted and limited to the Gauteng Province in South Africa. Findings are of value to clients, contractors and consultants and provides a basis for addressing arbitration effectively in the construction industry.
- Full Text:
- Date Issued: 2015
- Authors: Bvumbwe, Chikumbutso
- Date: 2015
- Subjects: Arbitration, Industrial -- South Africa Dispute resolution (Law) -- South Africa , Construction industry -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47981 , vital:40460
- Description: The study investigated the arbitration practice relative to the South African construction industry. Most of the construction contracts include an arbitration clause in the contract document as an instrument to be used for resolving disputes. The aim is to resolve disputes between the parties with minimum costs and within a reasonable period. Some parties opt to involve legal counsel in the process which has a potential of affecting time and cost. The literature review focuses on arbitration, in the construction industry, with a particular focus on how effective the methods are in terms of cost, time and the relationship between the disputing parties, the impact of using legal counsel during the arbitration process versus not involving legal counsel, the arbitration clause not specifying when to declare a dispute, and the perception of construction professionals on arbitration. The study was based on closed-ended questionnaires distributed among senior construction professionals including, architects, quantity surveyors, construction managers, project managers and practising attorneys. 61 respondents completed the questionnaire. The respondents were asked to comment on the effectiveness of alternative dispute resolution, cost, time, causes of disputes, and impacts of disputes. The cost of arbitration seems to escalate as a result of legal counsel being involved during the arbitration procedures. The time factor also seems to be prolonged. A notable finding indicates that the arbitration clause in the contract document should specify when to declare the dispute. The survey was conducted and limited to the Gauteng Province in South Africa. Findings are of value to clients, contractors and consultants and provides a basis for addressing arbitration effectively in the construction industry.
- Full Text:
- Date Issued: 2015
The effects of dietary soya and crystalline phytoestrogens on the growth, gonad development and histology of farmed abalone, Haliotis midae
- Wu, Yu
- Authors: Wu, Yu
- Date: 2015
- Subjects: Haliotis midae , Haliotis midae -- Feeding and feeds , Haliotis midae -- Growth , Haliotis midae -- Histology , Haliotis midae -- Effect of chemicals on , Soybean as feed , Phytoestrogens
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5380 , http://hdl.handle.net/10962/d1017225
- Description: The inclusion of soya as a dietary protein source in the formulated feed, Abfeed® S34 (Marifeed Pty (Ltd), Hermanus) for farmed abalone, Haliotis midae has resulted in larger gonads during reproductive seasons compared to the gonads of abalone fed kelp or diets that included fishmeal as the only main protein source. The aim of this study was to determine if the isoflavones present in the soya were responsible for this increase in gonad size and the subsequent effects on farmed abalone growth. Animals weighing between 40-50 g were fed one of seven isonitrogenous and isoenergetic diets containing either 0, 25, 50 or 100 percent of the soya component of the commercial feed (Abfeed® S34, Marifeed Pty (Ltd), Hermanus) from September 2013 to March 2014. An additional three diets were formulated to include crystalline isoflavone (ISO). These diets were identical to the 0 percent soya diet (i.e. the fishmeal only diet - FM), only ISO was included at the same rate that ISO occurred in the three soya diets. Data were analysed using a multiple forward stepwise regression analysis (MSR) to test the effects of ISO concentration, soya concentration, time, sex, time by concentration interaction and sex by concentration interaction on growth and gonad development and to identify those variables that most contributed to the model. The inclusion of crystalline ISO failed to promote larger gonads and had no effect on abalone growth, while growth and gonad development was dose dependent on soya inclusion rates with sex and time contributing to the models. Mean monthly weight gain in males correlated with increasing soya concentrations (c) (MSR, y = 3.24 + 0.002c, r2 = 0.23, p = 0.03), ranging from 3.11 ± 0.55 g abalone-1 month-1 to 4.43 ± 0.46 g abalone-1 month-1, while both male and female monthly length gain was not influenced by soya concentration with an overall mean of 1.62 ± 0.05 mm abalone-1 month-1 (MSR, p = 0.05 and p = 0.81, respectively). By December, the whole body mass, meat mass and visceral mass in both males and females decreased with increasing soya levels. However, by February, female whole body mass, meat mass and visceral mass positively correlated with soya levels. At the end of the study, male abalone fed FM with soya equivalent to the commercial feed had the highest whole body mass (69.00 ± 2.48 g abalone-1), meat mass (41.80 ± 1.12 g abalone-1), visceral mass (9.00 ± 2.47 g abalone-1) and gonad bulk index (42.70 ± 9.82 g abalone-1), while females were not influenced by soya concentrations with an overall whole body mass of 63.46 ± 0.79 g abalone-1. Weight loss was observed in all treatments between February and March, probably due to a spawning event. The moisture content in the meat was not influenced by treatment, however, visceral water loss was effected by both ISO and soya concentration with time and sex contributing to the model. The visceral water loss of females fed graded levels of soya decreased as a function of soya from December to March, and from December to February for males, whereas females fed ISO-enriched diets decreased as a function of ISO concentration (c) at the end of the study from 74.98 ± 0.88 to 73.10 ± 0.75 percent (MSR, y = 74.97 – 0.0025c, r2 = 0.20, p = 0.048). The inclusion of crystalline ISO had no significant effect on oogenesis in female farmed Haliotis midae, while the distribution of the predominant oocyte stage, stage 7 (second last stage prior to spawning) was dose-dependent in abalone fed increasing soya concentration (c) (MSR, y = 33.38 + 0.03c, r2 = 0.32, F(1, 18) = 8.52, p = 0.01). The increase in stage 7 oocytes in abalone fed FM with soya did not reduce the number of oocytes (44.96 ± 3.01 oocytes mm-2) present within the lumen, while the number of oocytes (o) in abalone fed the FM-only based diets decreased with increasing abundance of stage 7 oocytes (MSR, y = 58.28 – 0.48c, r2 = 0.38, F(1, 18) = 12.51, p = 0.002), possibly due to the increase in size of the oocytes with thicker jelly coats. This study provided evidence that crystalline isoflavone had no influence on abalone gonad development over five months, while soya had a dose-dependent effect on growth, gonad mass and oogenesis in farmed Haliotis midae. Formulated abalone feed could be manipulated at certain times of the year to obtain maximum growth. These implications and further studies were discussed.
- Full Text:
- Date Issued: 2015
- Authors: Wu, Yu
- Date: 2015
- Subjects: Haliotis midae , Haliotis midae -- Feeding and feeds , Haliotis midae -- Growth , Haliotis midae -- Histology , Haliotis midae -- Effect of chemicals on , Soybean as feed , Phytoestrogens
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5380 , http://hdl.handle.net/10962/d1017225
- Description: The inclusion of soya as a dietary protein source in the formulated feed, Abfeed® S34 (Marifeed Pty (Ltd), Hermanus) for farmed abalone, Haliotis midae has resulted in larger gonads during reproductive seasons compared to the gonads of abalone fed kelp or diets that included fishmeal as the only main protein source. The aim of this study was to determine if the isoflavones present in the soya were responsible for this increase in gonad size and the subsequent effects on farmed abalone growth. Animals weighing between 40-50 g were fed one of seven isonitrogenous and isoenergetic diets containing either 0, 25, 50 or 100 percent of the soya component of the commercial feed (Abfeed® S34, Marifeed Pty (Ltd), Hermanus) from September 2013 to March 2014. An additional three diets were formulated to include crystalline isoflavone (ISO). These diets were identical to the 0 percent soya diet (i.e. the fishmeal only diet - FM), only ISO was included at the same rate that ISO occurred in the three soya diets. Data were analysed using a multiple forward stepwise regression analysis (MSR) to test the effects of ISO concentration, soya concentration, time, sex, time by concentration interaction and sex by concentration interaction on growth and gonad development and to identify those variables that most contributed to the model. The inclusion of crystalline ISO failed to promote larger gonads and had no effect on abalone growth, while growth and gonad development was dose dependent on soya inclusion rates with sex and time contributing to the models. Mean monthly weight gain in males correlated with increasing soya concentrations (c) (MSR, y = 3.24 + 0.002c, r2 = 0.23, p = 0.03), ranging from 3.11 ± 0.55 g abalone-1 month-1 to 4.43 ± 0.46 g abalone-1 month-1, while both male and female monthly length gain was not influenced by soya concentration with an overall mean of 1.62 ± 0.05 mm abalone-1 month-1 (MSR, p = 0.05 and p = 0.81, respectively). By December, the whole body mass, meat mass and visceral mass in both males and females decreased with increasing soya levels. However, by February, female whole body mass, meat mass and visceral mass positively correlated with soya levels. At the end of the study, male abalone fed FM with soya equivalent to the commercial feed had the highest whole body mass (69.00 ± 2.48 g abalone-1), meat mass (41.80 ± 1.12 g abalone-1), visceral mass (9.00 ± 2.47 g abalone-1) and gonad bulk index (42.70 ± 9.82 g abalone-1), while females were not influenced by soya concentrations with an overall whole body mass of 63.46 ± 0.79 g abalone-1. Weight loss was observed in all treatments between February and March, probably due to a spawning event. The moisture content in the meat was not influenced by treatment, however, visceral water loss was effected by both ISO and soya concentration with time and sex contributing to the model. The visceral water loss of females fed graded levels of soya decreased as a function of soya from December to March, and from December to February for males, whereas females fed ISO-enriched diets decreased as a function of ISO concentration (c) at the end of the study from 74.98 ± 0.88 to 73.10 ± 0.75 percent (MSR, y = 74.97 – 0.0025c, r2 = 0.20, p = 0.048). The inclusion of crystalline ISO had no significant effect on oogenesis in female farmed Haliotis midae, while the distribution of the predominant oocyte stage, stage 7 (second last stage prior to spawning) was dose-dependent in abalone fed increasing soya concentration (c) (MSR, y = 33.38 + 0.03c, r2 = 0.32, F(1, 18) = 8.52, p = 0.01). The increase in stage 7 oocytes in abalone fed FM with soya did not reduce the number of oocytes (44.96 ± 3.01 oocytes mm-2) present within the lumen, while the number of oocytes (o) in abalone fed the FM-only based diets decreased with increasing abundance of stage 7 oocytes (MSR, y = 58.28 – 0.48c, r2 = 0.38, F(1, 18) = 12.51, p = 0.002), possibly due to the increase in size of the oocytes with thicker jelly coats. This study provided evidence that crystalline isoflavone had no influence on abalone gonad development over five months, while soya had a dose-dependent effect on growth, gonad mass and oogenesis in farmed Haliotis midae. Formulated abalone feed could be manipulated at certain times of the year to obtain maximum growth. These implications and further studies were discussed.
- Full Text:
- Date Issued: 2015
The ethical conduct of new entry level emerging contractors
- Authors: Van Schalkwyk, Tanya Leonie
- Date: 2015
- Subjects: Construction industry -- Moral and ethical aspects , Building -- Moral and ethical aspects , Construction workers -- Professional ethics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/4932 , vital:20769
- Description: Ethics is not a new or modern discipline. It was developed thousands of years ago and still remains relevant today. Ethics is applied in all spheres of modern life from philosophy to business and religious environments and even around dinner table conversations. It is applicable to all areas of life. This research is aimed at investigating whether ethical conduct among new entry level emerging contractors can contribute to and ensure their sustainable competitiveness within the South African construction industry. This research is also aimed at determining whether education and knowledge of entrepreneurship, business, project and construction management and building contracts can contribute to new entry level emerging contractors’ ethical conduct and sustainable competitiveness. The literature reviewed and results of quantitative and qualitative research amongst professional consultants in South Africa formed the basis of the study. Ethics is a sensitive topic within the industry and therefor it is difficult to gather data directly from contractors, as they are reluctant to participate in fear of revealing their identities and having it negatively influencing their personal and business credentials. Therefor unbiased respondents who were not directly linked to emerging contractors and who were unafraid to give objective opinions were questioned. These unbiased respondents included consultants within the industry. The study revealed that ethics is an important factor in any business environment and that the correct application thereof can partially contribute to the sustainable competitiveness of new entry level emerging contractors and this in turn can promote the long term survival of a business. Furthermore, knowledge of good management practices and building contracts can contribute to a successfully run business. However, the average new entry level emerging contractor has insufficient experience and knowledge of the management of construction projects, as well as building contracts.
- Full Text:
- Date Issued: 2015
- Authors: Van Schalkwyk, Tanya Leonie
- Date: 2015
- Subjects: Construction industry -- Moral and ethical aspects , Building -- Moral and ethical aspects , Construction workers -- Professional ethics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/4932 , vital:20769
- Description: Ethics is not a new or modern discipline. It was developed thousands of years ago and still remains relevant today. Ethics is applied in all spheres of modern life from philosophy to business and religious environments and even around dinner table conversations. It is applicable to all areas of life. This research is aimed at investigating whether ethical conduct among new entry level emerging contractors can contribute to and ensure their sustainable competitiveness within the South African construction industry. This research is also aimed at determining whether education and knowledge of entrepreneurship, business, project and construction management and building contracts can contribute to new entry level emerging contractors’ ethical conduct and sustainable competitiveness. The literature reviewed and results of quantitative and qualitative research amongst professional consultants in South Africa formed the basis of the study. Ethics is a sensitive topic within the industry and therefor it is difficult to gather data directly from contractors, as they are reluctant to participate in fear of revealing their identities and having it negatively influencing their personal and business credentials. Therefor unbiased respondents who were not directly linked to emerging contractors and who were unafraid to give objective opinions were questioned. These unbiased respondents included consultants within the industry. The study revealed that ethics is an important factor in any business environment and that the correct application thereof can partially contribute to the sustainable competitiveness of new entry level emerging contractors and this in turn can promote the long term survival of a business. Furthermore, knowledge of good management practices and building contracts can contribute to a successfully run business. However, the average new entry level emerging contractor has insufficient experience and knowledge of the management of construction projects, as well as building contracts.
- Full Text:
- Date Issued: 2015
The impact of non-compliance with Eskom procurement policies
- Authors: Mvelase, Thokozile Olivia
- Date: 2015
- Subjects: Eskom (Firm) , Industrial procurement -- Management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/9140 , vital:26468
- Description: Supply Chain Management (SCM) has an overwhelming impact on firms as it directly impacts on sales and costs. Therefore, it must be a core competency for any organization and thus SCM expertise is highly valued in organisations. Procurement of goods and services has a major impact on the successful execution of the project. Procurement can help the business, ensuring that all the goods and services they buy will be of the right quality, quantity and price, and they will be delivered ‘just in time’. The application of procurement policies and practices, using fair and open procedures, is crucial not only for attracting efficient contractors and suppliers, but also to safeguard the principle of accountability and the cost-effective use of funds. Before awarding a tender, there is a substantial amount of work to be undertaken by the project manager, contracts manager, end user, buyer, and authorising committees. Commitment from personnel involved in contract awarding is not adequate. Furthermore, the Eskom governance process sometimes contributes to delays in awarding a contract. before the enquiry and tender documentation is sent out to the suppliers on the tender list, the core team involved in the procurement process verifies that the enquiry is complete and correct. Should there be contractual or legal issues during the execution of the project in the form of say a contract that has been issued with unsuitable clauses, solving the problem becomes difficult. Contractors will sometimes use contract clauses to suit themselves, and take advantage of the employer, causing cost overruns due to the difficulties in managing the contract. Eskom’s commercial activities are governed by the Public Finance Management Act (PFMA) and Constitution of South Africa, which states that an organisation such as Eskom should have in place “an appropriate procurement and provisioning system which is fair, equitable, transparent, competitive, and cost-effective.” This can eliminate irregularities in contracts, since they can have a serious economic impact, interfere with fair competition, and destroy confidence in the integrity and functioning of public administration Such irregularities may lead to costs overruns on projects where incompetent contractors are awarded a contract. Incorrect financial forecasting is a very serious issue, and needs to be addressed in order to help strengthen the cash flow and forecasting within Eskom. This research strategy is intended for quantifying observations of human behaviour, with the emphasis on exact measurements. The primary data for this study was generated through the administration of a structured questionnaire survey conducted among engineers, project managers, contract managers, and forensics personnel. The secondary data for the present study was gathered from literature in the form of open ended questionnaire from the same personnel. Poor commitment of buyers and chain approval meetings being shifted affect the delays in awarding of contracts. Lack of training of contract managers, absence of legal representative’s advice and squad checking meetings not being represented properly contributes to contracts being awarded with unsuitable clauses. Managers specifically forcing contracts to be awarded to a specific contractor, nepotism or favoritism, politics and contractor greediness, relate to irregularities in contracts. Lack of experience, revision of scope (unclarified scope), project delays, less effort being made when forecasting and unforeseen circumstances, such as strikes, and forces of nature, relate to incorrect financial forecasting. Continuous training and commitment of all personnel involved in the project environment is important, therefore Eskom personnel in the project environment should work as a team in an integrated way. Adequate time should be spent, and thorough checks made, to ensure that documents sent out for tendering conform to requirements. Involvement of all the supporting functions must be maximised. Code of ethics training and application is very crucial in the project environment, and the current governance policies should be adhered to by all stakeholders in the project.
- Full Text:
- Date Issued: 2015
- Authors: Mvelase, Thokozile Olivia
- Date: 2015
- Subjects: Eskom (Firm) , Industrial procurement -- Management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/9140 , vital:26468
- Description: Supply Chain Management (SCM) has an overwhelming impact on firms as it directly impacts on sales and costs. Therefore, it must be a core competency for any organization and thus SCM expertise is highly valued in organisations. Procurement of goods and services has a major impact on the successful execution of the project. Procurement can help the business, ensuring that all the goods and services they buy will be of the right quality, quantity and price, and they will be delivered ‘just in time’. The application of procurement policies and practices, using fair and open procedures, is crucial not only for attracting efficient contractors and suppliers, but also to safeguard the principle of accountability and the cost-effective use of funds. Before awarding a tender, there is a substantial amount of work to be undertaken by the project manager, contracts manager, end user, buyer, and authorising committees. Commitment from personnel involved in contract awarding is not adequate. Furthermore, the Eskom governance process sometimes contributes to delays in awarding a contract. before the enquiry and tender documentation is sent out to the suppliers on the tender list, the core team involved in the procurement process verifies that the enquiry is complete and correct. Should there be contractual or legal issues during the execution of the project in the form of say a contract that has been issued with unsuitable clauses, solving the problem becomes difficult. Contractors will sometimes use contract clauses to suit themselves, and take advantage of the employer, causing cost overruns due to the difficulties in managing the contract. Eskom’s commercial activities are governed by the Public Finance Management Act (PFMA) and Constitution of South Africa, which states that an organisation such as Eskom should have in place “an appropriate procurement and provisioning system which is fair, equitable, transparent, competitive, and cost-effective.” This can eliminate irregularities in contracts, since they can have a serious economic impact, interfere with fair competition, and destroy confidence in the integrity and functioning of public administration Such irregularities may lead to costs overruns on projects where incompetent contractors are awarded a contract. Incorrect financial forecasting is a very serious issue, and needs to be addressed in order to help strengthen the cash flow and forecasting within Eskom. This research strategy is intended for quantifying observations of human behaviour, with the emphasis on exact measurements. The primary data for this study was generated through the administration of a structured questionnaire survey conducted among engineers, project managers, contract managers, and forensics personnel. The secondary data for the present study was gathered from literature in the form of open ended questionnaire from the same personnel. Poor commitment of buyers and chain approval meetings being shifted affect the delays in awarding of contracts. Lack of training of contract managers, absence of legal representative’s advice and squad checking meetings not being represented properly contributes to contracts being awarded with unsuitable clauses. Managers specifically forcing contracts to be awarded to a specific contractor, nepotism or favoritism, politics and contractor greediness, relate to irregularities in contracts. Lack of experience, revision of scope (unclarified scope), project delays, less effort being made when forecasting and unforeseen circumstances, such as strikes, and forces of nature, relate to incorrect financial forecasting. Continuous training and commitment of all personnel involved in the project environment is important, therefore Eskom personnel in the project environment should work as a team in an integrated way. Adequate time should be spent, and thorough checks made, to ensure that documents sent out for tendering conform to requirements. Involvement of all the supporting functions must be maximised. Code of ethics training and application is very crucial in the project environment, and the current governance policies should be adhered to by all stakeholders in the project.
- Full Text:
- Date Issued: 2015
The importance of demographic trends in forecasting energy demand for private households in South africa
- Authors: Thubeni,Sinethemba Morine
- Date: 2015
- Subjects: Electric power consumption -- South Africa -- Forecasting Households -- South Africa , Demography -- Economic aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/45322 , vital:38570
- Description: South Africa’s residential energy use is expected to grow at approximately the same rate as the population. Efficient planning for energy demand by energy suppliers is therefore, essential since shortage of energy will negatively affect economic growth.This paper aims to investigate the causal relationship between population and house-hold energy demand on coal, gas, paraffin and wood for private households in South Africa. The adjusted R2, AIC (Akaike information criterion), the BIC (Bayesian information criterion) and standard deviation of residuals were used to investigate which model is the best to predict energy demand in each province using all available information. The results show that population and household energy demand are associated with each other. The findings imply that the causality between population growth and household energy demand is bidirectional in most cases.
- Full Text:
- Date Issued: 2015
- Authors: Thubeni,Sinethemba Morine
- Date: 2015
- Subjects: Electric power consumption -- South Africa -- Forecasting Households -- South Africa , Demography -- Economic aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/45322 , vital:38570
- Description: South Africa’s residential energy use is expected to grow at approximately the same rate as the population. Efficient planning for energy demand by energy suppliers is therefore, essential since shortage of energy will negatively affect economic growth.This paper aims to investigate the causal relationship between population and house-hold energy demand on coal, gas, paraffin and wood for private households in South Africa. The adjusted R2, AIC (Akaike information criterion), the BIC (Bayesian information criterion) and standard deviation of residuals were used to investigate which model is the best to predict energy demand in each province using all available information. The results show that population and household energy demand are associated with each other. The findings imply that the causality between population growth and household energy demand is bidirectional in most cases.
- Full Text:
- Date Issued: 2015
The influence of the physical environment, topography and time on the inshore distribution of invertebrate larvae : a multi-taxon approach
- Authors: Duna, Oliver Olwethu
- Date: 2015
- Subjects: Benthic animals -- Larvae , Benthic animals -- Ecology , Plankton -- Larvae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5926 , http://hdl.handle.net/10962/d1017804
- Description: Coastal hydrodynamics regulate population dynamics through the distribution and dispersal of the meroplankton of many benthic invertebrates. I examined the hydrodynamics at four different sites on the south-east coast of South Africa and coupled them with larval sampling done at high temporal and spatial resolution. Day and night sampling was done at all four sites and a continuous 24 hour study was done in one site, both forms of sampling were carried out in autumn and spring. Samples were taken at two stations, 900 metres offshore and 300 metres apart, within each site. Water properties measured were depth, temperature and current velocity and direction. Plankton samples were collected using a plankton pump at various depths, from the surface, bottom and either side of the thermocline when present. A wide range of taxa (mostly bryozoans, bivalves, barnacles and decapods) was examined. 2-way ANOVAs were used to test the effects of time and depth on each taxon. In addition, multiple regression analyses were performed on each taxon to investigate the effects of hydrodynamics on the distribution of larvae. Bryozoanlarvae proved to be positively phototactic whilst bivalve veligers, barnacle larvae and decapod zoeae performed diel vertical migration. Turbulence and temperature had an effect on the vertical distribution/migration of decapod zoeae. These results highlight the role of taxon-specific responses to flow and the potential differential effects on larval retention and ultimately connectivity of benthic populations.
- Full Text:
- Date Issued: 2015
- Authors: Duna, Oliver Olwethu
- Date: 2015
- Subjects: Benthic animals -- Larvae , Benthic animals -- Ecology , Plankton -- Larvae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5926 , http://hdl.handle.net/10962/d1017804
- Description: Coastal hydrodynamics regulate population dynamics through the distribution and dispersal of the meroplankton of many benthic invertebrates. I examined the hydrodynamics at four different sites on the south-east coast of South Africa and coupled them with larval sampling done at high temporal and spatial resolution. Day and night sampling was done at all four sites and a continuous 24 hour study was done in one site, both forms of sampling were carried out in autumn and spring. Samples were taken at two stations, 900 metres offshore and 300 metres apart, within each site. Water properties measured were depth, temperature and current velocity and direction. Plankton samples were collected using a plankton pump at various depths, from the surface, bottom and either side of the thermocline when present. A wide range of taxa (mostly bryozoans, bivalves, barnacles and decapods) was examined. 2-way ANOVAs were used to test the effects of time and depth on each taxon. In addition, multiple regression analyses were performed on each taxon to investigate the effects of hydrodynamics on the distribution of larvae. Bryozoanlarvae proved to be positively phototactic whilst bivalve veligers, barnacle larvae and decapod zoeae performed diel vertical migration. Turbulence and temperature had an effect on the vertical distribution/migration of decapod zoeae. These results highlight the role of taxon-specific responses to flow and the potential differential effects on larval retention and ultimately connectivity of benthic populations.
- Full Text:
- Date Issued: 2015
The isolation, genetic characterisation and biological activity of a South African Phthorimaea operculella granulovirus (PhopGV-SA) for the control of the Potato Tuber Moth, Phthorimaea operculella (Zeller)
- Authors: Jukes, Michael David
- Date: 2015
- Subjects: Potato tuberworm , Potatoes -- Diseases and pests -- South Africa , Baculoviruses , Natural pesticides , Biological pest control agents , Potato tuberworm -- Biological control , Restriction enzymes, DNA
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4147 , http://hdl.handle.net/10962/d1017908
- Description: The potato tuber moth, Phthorimaea operculella (Zeller), is a major pest of potato crops worldwide causing significant damage to both field and stored tubers. The current control method in South Africa involves chemical insecticides, however, there is growing concern on the health and environmental risks of their use. The development of novel biopesticide based control methods may offer a potential solution for the future of insecticides. In this study a baculovirus was successfully isolated from a laboratory population of P. operculella. Transmission electron micrographs revealed granulovirus-like particles. DNA was extracted from recovered occlusion bodies and used for the PCR amplification of the lef-8, lef-9, granulin and egt genes. Sequence data was obtained and submitted to BLAST identifying the virus as a South African isolate of Phthorimaea operculella granulovirus (PhopGV-SA). Phylogenetic analysis of the lef-8, lef-9 and granulin amino acid sequences grouped the South African isolate with PhopGV-1346. Comparison of egt sequence data identified PhopGV-SA as a type II egt gene. A phylogenetic analysis of egt amino acid sequences grouped all type II genes, including PhopGV-SA, into a separate clade from types I, III, IV and V. These findings suggest that type II may represent the prototype structure for this gene with the evolution of types I, III and IV a result of large internal deletion events and subsequent divergence. PhopGV-SA was also shown to be genetically more similar to South American isolates (i.e. PhopGV-CHI or PhopGV-INDO) than it is to other African isolates, suggesting that the South African isolate originated from South America. Restriction endonuclease profiles of PhopGV-SA were similar to those of PhopGV-1346 and PhopGV-JLZ9f for the enzymes BamHI, HindIII, NruI and NdeI. A preliminary full genome sequence for PhopGV-SA was determined and compared to PhopGV-136 with some gene variation observed (i.e. odv-e66 and vp91/p95). The biological activity of PhopGV-SA against P. operculella neonate larvae was evaluated with an estimated LC₅₀ of 1.87×10⁸ OBs.ml⁻¹ being determined. This study therefore reports the characterisation of a novel South African PhopGV isolate which could potentially be developed into a biopesticide for the control of P. operculella.
- Full Text:
- Date Issued: 2015
- Authors: Jukes, Michael David
- Date: 2015
- Subjects: Potato tuberworm , Potatoes -- Diseases and pests -- South Africa , Baculoviruses , Natural pesticides , Biological pest control agents , Potato tuberworm -- Biological control , Restriction enzymes, DNA
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4147 , http://hdl.handle.net/10962/d1017908
- Description: The potato tuber moth, Phthorimaea operculella (Zeller), is a major pest of potato crops worldwide causing significant damage to both field and stored tubers. The current control method in South Africa involves chemical insecticides, however, there is growing concern on the health and environmental risks of their use. The development of novel biopesticide based control methods may offer a potential solution for the future of insecticides. In this study a baculovirus was successfully isolated from a laboratory population of P. operculella. Transmission electron micrographs revealed granulovirus-like particles. DNA was extracted from recovered occlusion bodies and used for the PCR amplification of the lef-8, lef-9, granulin and egt genes. Sequence data was obtained and submitted to BLAST identifying the virus as a South African isolate of Phthorimaea operculella granulovirus (PhopGV-SA). Phylogenetic analysis of the lef-8, lef-9 and granulin amino acid sequences grouped the South African isolate with PhopGV-1346. Comparison of egt sequence data identified PhopGV-SA as a type II egt gene. A phylogenetic analysis of egt amino acid sequences grouped all type II genes, including PhopGV-SA, into a separate clade from types I, III, IV and V. These findings suggest that type II may represent the prototype structure for this gene with the evolution of types I, III and IV a result of large internal deletion events and subsequent divergence. PhopGV-SA was also shown to be genetically more similar to South American isolates (i.e. PhopGV-CHI or PhopGV-INDO) than it is to other African isolates, suggesting that the South African isolate originated from South America. Restriction endonuclease profiles of PhopGV-SA were similar to those of PhopGV-1346 and PhopGV-JLZ9f for the enzymes BamHI, HindIII, NruI and NdeI. A preliminary full genome sequence for PhopGV-SA was determined and compared to PhopGV-136 with some gene variation observed (i.e. odv-e66 and vp91/p95). The biological activity of PhopGV-SA against P. operculella neonate larvae was evaluated with an estimated LC₅₀ of 1.87×10⁸ OBs.ml⁻¹ being determined. This study therefore reports the characterisation of a novel South African PhopGV isolate which could potentially be developed into a biopesticide for the control of P. operculella.
- Full Text:
- Date Issued: 2015
The relationship between religion/spirituality and the general psychological well-being of the institutionalized elderly population in the Eastern Cape, South Africa
- Authors: Walton, Karen Lynn
- Date: 2015
- Subjects: Psychology, Religious Psychology and religion
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5708 , vital:29366
- Description: Psychological well-being has a number of known benefits and is important for the quality of life of the elderly in particular. South Africa can be considered a religious country with the majority of citizens identifying with some religious orientation. The elderly are considered to be a more religious segment of the population, leading to a quantitative exploratory study being undertaken in order to ascertain whether a correlation exists between psychological well-being and religiosity/spirituality in the elderly institutionalised population of South Africa. The General Psychological Well-Being Scale and ASPIRES was administered to a convenience sample of 336 participants in the Eastern Cape Province. A significant but weak positive correlation was found between the variables of psychological well-being and religiosity. A difference was also found between White and African participants’ level of psychological well-being. An ANOVA was performed on the demographic information collected from participants. It was found that higher levels of education and access to private medical care were associated with higher levels of psychological well-being. A regression analysis was also performed on the data. It was found that although religiosity/spirituality does account for some of the variance, there were still a large number of other factors that influence psychological well-being in the elderly that were not captured in this study. Limitations of the study are that the results can’t be generalised to elderly residing at home. All of the participants also lived in urban areas and so differences may be found with rural elderly. Some further directions for research are discussed.
- Full Text:
- Date Issued: 2015
- Authors: Walton, Karen Lynn
- Date: 2015
- Subjects: Psychology, Religious Psychology and religion
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5708 , vital:29366
- Description: Psychological well-being has a number of known benefits and is important for the quality of life of the elderly in particular. South Africa can be considered a religious country with the majority of citizens identifying with some religious orientation. The elderly are considered to be a more religious segment of the population, leading to a quantitative exploratory study being undertaken in order to ascertain whether a correlation exists between psychological well-being and religiosity/spirituality in the elderly institutionalised population of South Africa. The General Psychological Well-Being Scale and ASPIRES was administered to a convenience sample of 336 participants in the Eastern Cape Province. A significant but weak positive correlation was found between the variables of psychological well-being and religiosity. A difference was also found between White and African participants’ level of psychological well-being. An ANOVA was performed on the demographic information collected from participants. It was found that higher levels of education and access to private medical care were associated with higher levels of psychological well-being. A regression analysis was also performed on the data. It was found that although religiosity/spirituality does account for some of the variance, there were still a large number of other factors that influence psychological well-being in the elderly that were not captured in this study. Limitations of the study are that the results can’t be generalised to elderly residing at home. All of the participants also lived in urban areas and so differences may be found with rural elderly. Some further directions for research are discussed.
- Full Text:
- Date Issued: 2015
The relative contribution of non-timber forest products, agriculture and off-farm sources of income to rural households in Koloni and Guquka, Eastern Cape
- Authors: Mtati, Nosiseko
- Date: 2015
- Subjects: Informal sector (Economics) -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape , Rural poor -- South Africa -- Eastern Cape , Households -- Economic aspects -- South Africa -- Eastern Cape , Forest products -- South Africa -- Eastern Cape , Non-timber forest products -- South Africa -- Eastern Cape , Agriculture -- Economic aspects -- South Africa -- Eastern Cape , Natural resources -- South Africa -- Eastern Cape , Income -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4785 , http://hdl.handle.net/10962/d1018193
- Description: [Partial abstract]: This study was carried out to determine the contribution of non-timber forest products (NTFPs) to household total income, other livelihood sectors were also examined simultaneously. The contribution of agriculture involved livestock and crop production. Wages and government grants were other livelihood sectors that were looked into. This study was important in determining the change in livelihood strategies in the last decade and to quantify the NTFPs used at the two sites. It was carried out in Guquka and Koloni, both part of the central Eastern Cape. Information on direct use value of the NTFPs used, the quantities and local price; crop production outputs and inputs and the costs. Data were collected via a questionnaire.
- Full Text:
- Date Issued: 2015
- Authors: Mtati, Nosiseko
- Date: 2015
- Subjects: Informal sector (Economics) -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape , Rural poor -- South Africa -- Eastern Cape , Households -- Economic aspects -- South Africa -- Eastern Cape , Forest products -- South Africa -- Eastern Cape , Non-timber forest products -- South Africa -- Eastern Cape , Agriculture -- Economic aspects -- South Africa -- Eastern Cape , Natural resources -- South Africa -- Eastern Cape , Income -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4785 , http://hdl.handle.net/10962/d1018193
- Description: [Partial abstract]: This study was carried out to determine the contribution of non-timber forest products (NTFPs) to household total income, other livelihood sectors were also examined simultaneously. The contribution of agriculture involved livestock and crop production. Wages and government grants were other livelihood sectors that were looked into. This study was important in determining the change in livelihood strategies in the last decade and to quantify the NTFPs used at the two sites. It was carried out in Guquka and Koloni, both part of the central Eastern Cape. Information on direct use value of the NTFPs used, the quantities and local price; crop production outputs and inputs and the costs. Data were collected via a questionnaire.
- Full Text:
- Date Issued: 2015
The role of seasonality, environmental correlates and edge effects on the diversity and abundance of small mammals in Afromontane forest patches, Eastern Cape, South Africa
- Authors: Junkuhn, Kyle Peter
- Date: 2015
- Subjects: Upland ecology -- South Africa -- Eastern Cape , Mammal populations -- South Africa -- Eastern Cape , Forest animals -- Adaptation -- South Africa -- Eastern Cape , Forest animals -- Climatic factors -- South Africa -- Eastern Cape , Forest animals -- Effect of habitat modification on -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4270 , http://hdl.handle.net/10962/d1018188
- Description: The Eastern Cape contains the majority of the remaining forested areas in South Africa (95.8 percent Coastal forests and 47.6 percent Afromontane forests), however these occur in fragments. Due to the rapid rise in the human population and its needs, conversion of forests to agricultural land and the extraction of timber increases, natural vegetation are lost and this therefore leads to forests becoming fragmented into small forest patches. One of the main consequences of forest fragmentation is loss of contiguous habitat, which is the dominant threat to species globally as it negatively affects both species richness and genetic diversity. This research investigates the effects that forest fragmentation has on small mammal diversity and abundance. The study sampled small mammals in Southern Mistbelt Afromontane forest patches in the Eastern Cape. The first aim of this study was to identify which environmental variable, or combinations of variables, affect the diversity and abundance of small mammals in fragmented forest patches in the Eastern Cape during the austral summer. The second aim was to compare seasonal changes in small mammal diversity and abundance at a forest edge compared to the forest core at Beggars Bush, an Afromontane forest in the Eastern Cape, South Africa. To identify the environmental impacts that different forests have on small mammals, nine different forests were chosen in the Eastern Cape and sampled during the summer in 2013. These nine forests were: Fort Fordyce Forest, Thaba Ndoda Forest, Hogsback Forest, Dassie Kraans Forest, Langeni Forest, Burchell’s Reserve Forest, Maiden Dam Forest and Kagaberg Forest. At each site, three transects of 30 Sherman Traps each were used. Trapping periods within each forest patch lasted between three to five consecutive nights and traps were inspected once a day in the morning. Nine environmental variables were initially identified and after being tested for normality and colinearity, five variables were chosen. These variables were Altitude, Mean Annual Temperature, Gradient, Patch Size and Mean annual potential evaporation. The number of individuals captures and species richness were then incorporated as dependent variables for best subset multiple regression model selection using the Akaike Information Criterion (AIC). For the second aim, the same trapping methods were used when comparing seasonal changes to diversity and abundance within the forest core. However at the forest edge, due to the small size of the forest, only 20 Sherman traps were used in each transect with five traps (25 percent) placed in the grassland and 15 (75 percent) placed in the forest along each transect. This study was one of few to survey small mammal diversity and abundance in fragmented forests in the Eastern Cape. Gradient, patch size and mean annual potential evaporation were the variables that best predicted the individual number of small mammal captures while only gradient best explained species richness. It does however, need to be noted that capture rates and species richness were very low and this would therefore effect the analysis of environmental variables. Future studies should have a larger sample size of forest patches and include more microhabitat environmental variables to determine their effects on small mammal diversity and abundance. However, it should be noted that through climatic extinction filtering, forest mammals are resilient generalists that can tolerate fragmentation effects. Furthermore, it was found that forest edges appear to play a significant role in small mammal diversity and abundance in the Beggars Bush Afromontane forest. Some species were habitat specialists such as Rhabdomys pumilio preferring the grassland habitat and Graphiurus murinus and Aethomys namaquensis the forest habitat, while Myosorex varius was the only species that was not habitat dependant. It was found that there was a greater diversity and abundance at the forest edge compared to within the forest core throughout most of the seasons. One possible flaw was that the sampling methods were different at the edge and within the forest and therefore future studies should ensure that the method stays uniform throughout the study.
- Full Text:
- Date Issued: 2015
- Authors: Junkuhn, Kyle Peter
- Date: 2015
- Subjects: Upland ecology -- South Africa -- Eastern Cape , Mammal populations -- South Africa -- Eastern Cape , Forest animals -- Adaptation -- South Africa -- Eastern Cape , Forest animals -- Climatic factors -- South Africa -- Eastern Cape , Forest animals -- Effect of habitat modification on -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4270 , http://hdl.handle.net/10962/d1018188
- Description: The Eastern Cape contains the majority of the remaining forested areas in South Africa (95.8 percent Coastal forests and 47.6 percent Afromontane forests), however these occur in fragments. Due to the rapid rise in the human population and its needs, conversion of forests to agricultural land and the extraction of timber increases, natural vegetation are lost and this therefore leads to forests becoming fragmented into small forest patches. One of the main consequences of forest fragmentation is loss of contiguous habitat, which is the dominant threat to species globally as it negatively affects both species richness and genetic diversity. This research investigates the effects that forest fragmentation has on small mammal diversity and abundance. The study sampled small mammals in Southern Mistbelt Afromontane forest patches in the Eastern Cape. The first aim of this study was to identify which environmental variable, or combinations of variables, affect the diversity and abundance of small mammals in fragmented forest patches in the Eastern Cape during the austral summer. The second aim was to compare seasonal changes in small mammal diversity and abundance at a forest edge compared to the forest core at Beggars Bush, an Afromontane forest in the Eastern Cape, South Africa. To identify the environmental impacts that different forests have on small mammals, nine different forests were chosen in the Eastern Cape and sampled during the summer in 2013. These nine forests were: Fort Fordyce Forest, Thaba Ndoda Forest, Hogsback Forest, Dassie Kraans Forest, Langeni Forest, Burchell’s Reserve Forest, Maiden Dam Forest and Kagaberg Forest. At each site, three transects of 30 Sherman Traps each were used. Trapping periods within each forest patch lasted between three to five consecutive nights and traps were inspected once a day in the morning. Nine environmental variables were initially identified and after being tested for normality and colinearity, five variables were chosen. These variables were Altitude, Mean Annual Temperature, Gradient, Patch Size and Mean annual potential evaporation. The number of individuals captures and species richness were then incorporated as dependent variables for best subset multiple regression model selection using the Akaike Information Criterion (AIC). For the second aim, the same trapping methods were used when comparing seasonal changes to diversity and abundance within the forest core. However at the forest edge, due to the small size of the forest, only 20 Sherman traps were used in each transect with five traps (25 percent) placed in the grassland and 15 (75 percent) placed in the forest along each transect. This study was one of few to survey small mammal diversity and abundance in fragmented forests in the Eastern Cape. Gradient, patch size and mean annual potential evaporation were the variables that best predicted the individual number of small mammal captures while only gradient best explained species richness. It does however, need to be noted that capture rates and species richness were very low and this would therefore effect the analysis of environmental variables. Future studies should have a larger sample size of forest patches and include more microhabitat environmental variables to determine their effects on small mammal diversity and abundance. However, it should be noted that through climatic extinction filtering, forest mammals are resilient generalists that can tolerate fragmentation effects. Furthermore, it was found that forest edges appear to play a significant role in small mammal diversity and abundance in the Beggars Bush Afromontane forest. Some species were habitat specialists such as Rhabdomys pumilio preferring the grassland habitat and Graphiurus murinus and Aethomys namaquensis the forest habitat, while Myosorex varius was the only species that was not habitat dependant. It was found that there was a greater diversity and abundance at the forest edge compared to within the forest core throughout most of the seasons. One possible flaw was that the sampling methods were different at the edge and within the forest and therefore future studies should ensure that the method stays uniform throughout the study.
- Full Text:
- Date Issued: 2015
The roles of black-backed jackals and caracals in issues of human-wildlife conflict in the Eastern Cape, South Africa
- Authors: Murison, Megan Kate
- Date: 2015
- Subjects: Black-backed jackal -- South Africa -- Eastern Cape , Human-animal relationships -- South Africa -- Eastern Cape , Predatory animals -- Control -- South Africa -- Eastern Cape , Black-backed jackal -- Food -- South Africa -- Eastern Cape , Black-backed jackal -- Effect of human beings on -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5939 , http://hdl.handle.net/10962/d1018667
- Description: [Partial abstract]: Human-wildlife conflict is a widely observed phenomenon and encompasses a range of negative interactions between humans and wildlife. Depredation upon livestock and game species proves to be the prevalent form of this conflict and often results in the killing of carnivores. Within the South African context, despite intense lethal control, two sympatric mesopredators, the blackbacked jackal (Canis mesomelas) and the caracal (Caracal caracal), remain common enough to be considered a major threat to human livelihoods through depredation. Wildlife ranches and livestock farms dominate the landscape in the Eastern Cape Province. Moreover, human-predator conflict within the region is extensive as both the black-backed jackal and caracal are seen to be inimical by landowners. Understanding this conflict is essential for mitigating any potential adverse environmental reactions (i.e. range collapses or extinctions) and requires knowledge of anthropogenic, ecological and environmental factors. I interviewed 73 land owners across five municipal boundaries in the Eastern Cape to quantify perceptions of predator control methods.
- Full Text:
- Date Issued: 2015
- Authors: Murison, Megan Kate
- Date: 2015
- Subjects: Black-backed jackal -- South Africa -- Eastern Cape , Human-animal relationships -- South Africa -- Eastern Cape , Predatory animals -- Control -- South Africa -- Eastern Cape , Black-backed jackal -- Food -- South Africa -- Eastern Cape , Black-backed jackal -- Effect of human beings on -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5939 , http://hdl.handle.net/10962/d1018667
- Description: [Partial abstract]: Human-wildlife conflict is a widely observed phenomenon and encompasses a range of negative interactions between humans and wildlife. Depredation upon livestock and game species proves to be the prevalent form of this conflict and often results in the killing of carnivores. Within the South African context, despite intense lethal control, two sympatric mesopredators, the blackbacked jackal (Canis mesomelas) and the caracal (Caracal caracal), remain common enough to be considered a major threat to human livelihoods through depredation. Wildlife ranches and livestock farms dominate the landscape in the Eastern Cape Province. Moreover, human-predator conflict within the region is extensive as both the black-backed jackal and caracal are seen to be inimical by landowners. Understanding this conflict is essential for mitigating any potential adverse environmental reactions (i.e. range collapses or extinctions) and requires knowledge of anthropogenic, ecological and environmental factors. I interviewed 73 land owners across five municipal boundaries in the Eastern Cape to quantify perceptions of predator control methods.
- Full Text:
- Date Issued: 2015
The synthesis and analysis of (2R,3R)-1,1,4,4- tetraphenylbutane-1,2,3,4-tetraol (tetrol) and derivatives, and a study of their host potential
- Authors: Weitz, Selwyn Herbert
- Date: 2015
- Subjects: Chemistry, Organic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/3735 , vital:20459
- Description: This investigation focussed on the inclusion and resolution ability of (2R,3R)-1,1,4,4-tetraphenylbutane-1,2,3,4-tetraol (TETROL), studies on the stoichiometry of its derivatives and the formation of inclusion compounds for single crystal analysis. The guest compounds that featured in the main study were cyclohexanone, 2-methylcyclohexanone, 3-methylcyclohexanone and 4-methylcyclohexanone. It was found that 3- and 4-methylcyclohexanone were trapped in their energetically unfavourable axial conformations in the inclusion crystal. Resolution experiments proved that (2R,3R)-1,1,4,4-tetraphenylbutane-1,2,3,4-tetraol can be used as a resolving agent for 2- and 3-methylcyclohexanone, with ee values of 13% and 22%, respectively (according to the method of Hiemstra), in favour of the R-enantiomer. Single crystal X-ray diffraction (SCXRD) studies, however, showed that 2-methylcyclohexanone was resolved with an ee of 30% in R. An ee of 56% in R was obtained for 3-methylcyclohexanone. Enantiomer enrichment of 2-methylcyclohexanone was achieved in basic medium (ee of 18% according to the method of Hiemstra) and showed that by using the host in either half or double the molar ratio of the guest, a higher ee was obtained than for a 1:1 ratio. The following TETROL derivatives were also synthesized and their stoichiometries with various guest compounds were determined: (2R,3R)-1,1,4,4-tetra(naphthalen-1-yl)butane-1,2,3,4-tetraol; (2R,3R)-1,1,4,4-tetra(naphthalen-2-yl)butane-1,2,3,4-tetraol; (2R,3R)-1,1,4,4-tetra(p-anisyl)butane-1,2,3,4-tetraol; (2R,3R)-1,1,4,4-tetra(p-tolyl)butane-1,2,3,4-tetraol; (2R,3R)-1,1,4,4-tetra(m-tolyl)butane-1,2,3,4-tetraol and; (2R,3R)-1,1,4,4-tetra(o-tolyl)butane-1,2,3,4-tetraol.
- Full Text:
- Date Issued: 2015
- Authors: Weitz, Selwyn Herbert
- Date: 2015
- Subjects: Chemistry, Organic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/3735 , vital:20459
- Description: This investigation focussed on the inclusion and resolution ability of (2R,3R)-1,1,4,4-tetraphenylbutane-1,2,3,4-tetraol (TETROL), studies on the stoichiometry of its derivatives and the formation of inclusion compounds for single crystal analysis. The guest compounds that featured in the main study were cyclohexanone, 2-methylcyclohexanone, 3-methylcyclohexanone and 4-methylcyclohexanone. It was found that 3- and 4-methylcyclohexanone were trapped in their energetically unfavourable axial conformations in the inclusion crystal. Resolution experiments proved that (2R,3R)-1,1,4,4-tetraphenylbutane-1,2,3,4-tetraol can be used as a resolving agent for 2- and 3-methylcyclohexanone, with ee values of 13% and 22%, respectively (according to the method of Hiemstra), in favour of the R-enantiomer. Single crystal X-ray diffraction (SCXRD) studies, however, showed that 2-methylcyclohexanone was resolved with an ee of 30% in R. An ee of 56% in R was obtained for 3-methylcyclohexanone. Enantiomer enrichment of 2-methylcyclohexanone was achieved in basic medium (ee of 18% according to the method of Hiemstra) and showed that by using the host in either half or double the molar ratio of the guest, a higher ee was obtained than for a 1:1 ratio. The following TETROL derivatives were also synthesized and their stoichiometries with various guest compounds were determined: (2R,3R)-1,1,4,4-tetra(naphthalen-1-yl)butane-1,2,3,4-tetraol; (2R,3R)-1,1,4,4-tetra(naphthalen-2-yl)butane-1,2,3,4-tetraol; (2R,3R)-1,1,4,4-tetra(p-anisyl)butane-1,2,3,4-tetraol; (2R,3R)-1,1,4,4-tetra(p-tolyl)butane-1,2,3,4-tetraol; (2R,3R)-1,1,4,4-tetra(m-tolyl)butane-1,2,3,4-tetraol and; (2R,3R)-1,1,4,4-tetra(o-tolyl)butane-1,2,3,4-tetraol.
- Full Text:
- Date Issued: 2015
The trophic ecology of the endangered endemic Barau's Petrel (Pterodroma baraui) from Reunion Island, south-western Indian Ocean
- Authors: Danckwerts, Daniel Keith
- Date: 2015
- Subjects: Petrels -- Réunion , Pterodroma baraui , Ecology -- Réunion
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5925 , http://hdl.handle.net/10962/d1017803
- Description: Réunion is the only tropical island that supports two endemic gadfly petrels. Population modelling has indicated that the current threats to the Barau’s Petrel (Pterodroma baraui) may drive it to extinction; this fate is almost definite for the Mascarene Petrel (Pseudobulweria aterrima). Management interventions have therefore been implemented, but conservation potential is handicapped since virtually nothing is known about the former species’ at-sea biology. Thus, following numerous recommendations, this study aimed to combine stomach content, stable isotope, and fatty acid analyses so to provide new information on the at-sea ecology of Barau’s Petrel. Breeding colonies were repeatedly visited over the same season and samples gathered from adults, fledglings, and downy chicks. Stomach contents consisted mostly of accumulated cephalopod beaks whereas structures from fishes, molluscs, arthropods, and crustaceans were less frequently encountered. Fatty acid profiles of blood varied greatly among individuals and the lowincidences of monounsaturated and n-3 fatty acids discounted fish as an important dietary component. δ¹⁵N of blood indicated a niche between the fourth and fifth trophic levels, which proposes that these birds scavenge to a greater degree than other sympatric seabirds and suggests that adults are also reliant on their endogenous reserves during breeding. δ¹³C values confirmed the migratory behaviour of adults since birds returning from the non-breeding grounds were enriched relative to individuals sampled through the breeding period. Significant intra-breeding season variations in δ13C were also observed, which matched this species’ patterns of habitat use as have recently described. These results collectively indicate an opportunistic behaviour, which implies some degree of resilience against shifts in prey availability/accessibility, and suggest that this species’ reproduction isdependent on distant foraging areas. This breeding strategy is synonymous with great vulnerability as over-investing into a single breeding episode may jeopardize future survival and fecundity. Thus, in light of environmental conditions that are becoming increasingly more susceptible to dramatic changes, the birds could rather be prioritising adult survival, over reproductive output. Further work is obviously necessary and should benefit from databases of fatty acid profiles and isotope signatures of potential prey species.
- Full Text:
- Date Issued: 2015
- Authors: Danckwerts, Daniel Keith
- Date: 2015
- Subjects: Petrels -- Réunion , Pterodroma baraui , Ecology -- Réunion
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5925 , http://hdl.handle.net/10962/d1017803
- Description: Réunion is the only tropical island that supports two endemic gadfly petrels. Population modelling has indicated that the current threats to the Barau’s Petrel (Pterodroma baraui) may drive it to extinction; this fate is almost definite for the Mascarene Petrel (Pseudobulweria aterrima). Management interventions have therefore been implemented, but conservation potential is handicapped since virtually nothing is known about the former species’ at-sea biology. Thus, following numerous recommendations, this study aimed to combine stomach content, stable isotope, and fatty acid analyses so to provide new information on the at-sea ecology of Barau’s Petrel. Breeding colonies were repeatedly visited over the same season and samples gathered from adults, fledglings, and downy chicks. Stomach contents consisted mostly of accumulated cephalopod beaks whereas structures from fishes, molluscs, arthropods, and crustaceans were less frequently encountered. Fatty acid profiles of blood varied greatly among individuals and the lowincidences of monounsaturated and n-3 fatty acids discounted fish as an important dietary component. δ¹⁵N of blood indicated a niche between the fourth and fifth trophic levels, which proposes that these birds scavenge to a greater degree than other sympatric seabirds and suggests that adults are also reliant on their endogenous reserves during breeding. δ¹³C values confirmed the migratory behaviour of adults since birds returning from the non-breeding grounds were enriched relative to individuals sampled through the breeding period. Significant intra-breeding season variations in δ13C were also observed, which matched this species’ patterns of habitat use as have recently described. These results collectively indicate an opportunistic behaviour, which implies some degree of resilience against shifts in prey availability/accessibility, and suggest that this species’ reproduction isdependent on distant foraging areas. This breeding strategy is synonymous with great vulnerability as over-investing into a single breeding episode may jeopardize future survival and fecundity. Thus, in light of environmental conditions that are becoming increasingly more susceptible to dramatic changes, the birds could rather be prioritising adult survival, over reproductive output. Further work is obviously necessary and should benefit from databases of fatty acid profiles and isotope signatures of potential prey species.
- Full Text:
- Date Issued: 2015
The use of probiotics in the diet of farmed South African abalone Haliotis midae L
- Authors: Maliza, Siyabonga
- Date: 2015
- Subjects: Haliotis midae -- South Africa , Abalones -- South Africa , Haliotis midae -- Feeding and feeds , Haliotis midae -- Effect of chemicals on , Haliotis midae -- Growth , Haliotis midae -- Immunology , Probiotics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5382 , http://hdl.handle.net/10962/d1018178
- Description: Physiological stress in farmed abalone can lead to immunosuppression and increase the susceptibility to bacterial, viral and parasitic disease, often followed by mortality. Thus, handling and poor water quality can reduce farm production efficiency. Probiotics in aquaculture have been effective in a wide range of species in enhancing immunity, survival, improving feed utilisation and growth. Three putative probionts identified as a result of in vitro screening had been beneficial to laboratory-reared abalone in a previous study. The aim of this study was to produce an abalone feed that contains a suite of probionts that may promote abalone growth and health under farming conditions. The objectives were to compare growth and physiological responses (i.e., haemocyte and phagocytosis counts) of abalone fed a commercial feed (Abfeed®S 34, Marifeed, Hermanus) supplemented with probiotics (i.e., the probiotic diet) to abalone fed the commercial feed without probiotic supplementation as a control treatment in a factorial design with handling method as an independent variable. This experiment was conducted at HIK Abalone Farm (Pty Ltd) for a period of eight months with initial weight and length 36.1 ± 0.05 g and 58.6 ± 0.06 mm abalone-1. Another experiment was carried out at Roman Bay Sea Farm (Pty) Ltd with initial weight and length 34.7 ± 0.17 g and 62.3 ± 0.18 mm abalone-1, but this experiment included one factor only, i.e. the presence and absence of the probionts in the feed. At HIK there was no significant interaction between diet and handling on average length and weight gain month-1 after four (p=0.81 and p=0.32) and eight (p=0.51 and p=0.53) months, respectively. Average length (additional handling = 73.9 ± 0.52 mm, normal farm handling = 75.8 ± 0.57 mm) and weight gain (mean: additional handling = 68.5 ± 1.20 g, normal farm handling = 74.3 ± 1.86 g) increased significantly in animals that were handled under normal farm procedure and were either fed probiotic or control diet after eight months (p=0.03 and p=0.02, respectively). There was no iii difference in length gain or weight gain of abalone fed the probiotic diet and those fed the control diet (ANOVA: F(1,16)=0.04, p=0.84; F(1,16)=0.14, p=0.71, respectively). After four months phagocytotic count was significantly different between dietary treatments with mean values of 74.50 ± 10.52 and 63.52 ± 14.52 % phagocytosis count per sample for the probionts and control treatment, respectively (p=0.04), there was no difference after eight months at HIK Abalone Farm. There was no effect of stressor application (p=0.14) and no interaction between dietary treatment and stressor application for this variable i.e., phagocytosis count (p=0.61). There was no difference in feed conversion ratio between treatments with values ranging from 2.9 to 3.8. At Roman Bay Sea farm, there was no significant difference in mean length gain between abalone fed the probiotic and control diet after eight months (repeated measures ANOVA: F(4,28)=16.54. Mean weight gain of abalone fed the probiotic diet was significantly greater than those fed the control diet after eight months (repeated measures ANOVA: F(4,28)=39.82, p(0.00001). There was no significant difference in haemocyte counts between animals fed either probiotic or control diet after four and eight months at Roman Bay Sea farm (p>0.05).
- Full Text:
- Date Issued: 2015
- Authors: Maliza, Siyabonga
- Date: 2015
- Subjects: Haliotis midae -- South Africa , Abalones -- South Africa , Haliotis midae -- Feeding and feeds , Haliotis midae -- Effect of chemicals on , Haliotis midae -- Growth , Haliotis midae -- Immunology , Probiotics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5382 , http://hdl.handle.net/10962/d1018178
- Description: Physiological stress in farmed abalone can lead to immunosuppression and increase the susceptibility to bacterial, viral and parasitic disease, often followed by mortality. Thus, handling and poor water quality can reduce farm production efficiency. Probiotics in aquaculture have been effective in a wide range of species in enhancing immunity, survival, improving feed utilisation and growth. Three putative probionts identified as a result of in vitro screening had been beneficial to laboratory-reared abalone in a previous study. The aim of this study was to produce an abalone feed that contains a suite of probionts that may promote abalone growth and health under farming conditions. The objectives were to compare growth and physiological responses (i.e., haemocyte and phagocytosis counts) of abalone fed a commercial feed (Abfeed®S 34, Marifeed, Hermanus) supplemented with probiotics (i.e., the probiotic diet) to abalone fed the commercial feed without probiotic supplementation as a control treatment in a factorial design with handling method as an independent variable. This experiment was conducted at HIK Abalone Farm (Pty Ltd) for a period of eight months with initial weight and length 36.1 ± 0.05 g and 58.6 ± 0.06 mm abalone-1. Another experiment was carried out at Roman Bay Sea Farm (Pty) Ltd with initial weight and length 34.7 ± 0.17 g and 62.3 ± 0.18 mm abalone-1, but this experiment included one factor only, i.e. the presence and absence of the probionts in the feed. At HIK there was no significant interaction between diet and handling on average length and weight gain month-1 after four (p=0.81 and p=0.32) and eight (p=0.51 and p=0.53) months, respectively. Average length (additional handling = 73.9 ± 0.52 mm, normal farm handling = 75.8 ± 0.57 mm) and weight gain (mean: additional handling = 68.5 ± 1.20 g, normal farm handling = 74.3 ± 1.86 g) increased significantly in animals that were handled under normal farm procedure and were either fed probiotic or control diet after eight months (p=0.03 and p=0.02, respectively). There was no iii difference in length gain or weight gain of abalone fed the probiotic diet and those fed the control diet (ANOVA: F(1,16)=0.04, p=0.84; F(1,16)=0.14, p=0.71, respectively). After four months phagocytotic count was significantly different between dietary treatments with mean values of 74.50 ± 10.52 and 63.52 ± 14.52 % phagocytosis count per sample for the probionts and control treatment, respectively (p=0.04), there was no difference after eight months at HIK Abalone Farm. There was no effect of stressor application (p=0.14) and no interaction between dietary treatment and stressor application for this variable i.e., phagocytosis count (p=0.61). There was no difference in feed conversion ratio between treatments with values ranging from 2.9 to 3.8. At Roman Bay Sea farm, there was no significant difference in mean length gain between abalone fed the probiotic and control diet after eight months (repeated measures ANOVA: F(4,28)=16.54. Mean weight gain of abalone fed the probiotic diet was significantly greater than those fed the control diet after eight months (repeated measures ANOVA: F(4,28)=39.82, p(0.00001). There was no significant difference in haemocyte counts between animals fed either probiotic or control diet after four and eight months at Roman Bay Sea farm (p>0.05).
- Full Text:
- Date Issued: 2015
Tillage effects on the aggregate-associated organic carbon and bulk density in some South African soils with different texture
- Authors: Njeru, Sarah Kangai
- Date: 2015
- Subjects: Soil management Tillage
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2512 , vital:27881
- Description: Tillage operations disrupt the soil structure resulting in aggregates of various sizes and altered bulk density. Moreover, tillage influences soil carbon pools and many other soil physical properties. The objectives of this study were to determine, in various South African soils under different tillage systems, the following. (1) Amount of aggregate-associated soil organic carbon (SOC), (2) soil compressibility, and (3) relationship between compressibility, texture and the aggregate-associated SOC. The soil samples used in this study were collected from six different sites in Eastern Cape Province, South Africa. Soil samples were taken from conventional tillage (CT) and no-till (NT) land. To keep the soil aggregates intact sampling was done using a spade and carefully carried to the laboratory in rigid containers. For SOC determination, treatments were the two tillage systems, CT and NT, and four aggregate sizes. The experimental design was completely randomized design with a factorial layout and was replicated three times. Aggregate-associated SOC was determined using Walkley-Black method. Proctor compaction test was used determine the dry bulk density with varying moisture content and consequently the maximum bulk density (MBD) and critical water content (CWC). The aggregate-associated SOC content differed with tillage system and was significant higher (p < 0.05) in CT than NT. The amount of aggregate-associated SOC was 1.67 times higher in CT than NT plots. The MBD ranged between 1.77 g/cm3 and 10.27 g/cm3 and the CWC ranged from 9.1 percent to 10.3 percent. The higher amounts of SOC in CT were attributed to the annual crop residue returns while the lower amounts of SOC in the NT fields were due to grazing. Therefore, tillage influenced the amount of aggregate-associated organic carbon irrespective of the resulting size of the aggregate. The positive relationship between tillage and aggregate-associated SOC challenges the conversion of land to no-till for carbon sequestration. The overall gradient for correlation between the MBD and CWC was negative with r2 = 0.23 and a p value of 0.0076. The compressibility curves indicated higher values under CT if the texture class was silt clay.
- Full Text:
- Date Issued: 2015
- Authors: Njeru, Sarah Kangai
- Date: 2015
- Subjects: Soil management Tillage
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2512 , vital:27881
- Description: Tillage operations disrupt the soil structure resulting in aggregates of various sizes and altered bulk density. Moreover, tillage influences soil carbon pools and many other soil physical properties. The objectives of this study were to determine, in various South African soils under different tillage systems, the following. (1) Amount of aggregate-associated soil organic carbon (SOC), (2) soil compressibility, and (3) relationship between compressibility, texture and the aggregate-associated SOC. The soil samples used in this study were collected from six different sites in Eastern Cape Province, South Africa. Soil samples were taken from conventional tillage (CT) and no-till (NT) land. To keep the soil aggregates intact sampling was done using a spade and carefully carried to the laboratory in rigid containers. For SOC determination, treatments were the two tillage systems, CT and NT, and four aggregate sizes. The experimental design was completely randomized design with a factorial layout and was replicated three times. Aggregate-associated SOC was determined using Walkley-Black method. Proctor compaction test was used determine the dry bulk density with varying moisture content and consequently the maximum bulk density (MBD) and critical water content (CWC). The aggregate-associated SOC content differed with tillage system and was significant higher (p < 0.05) in CT than NT. The amount of aggregate-associated SOC was 1.67 times higher in CT than NT plots. The MBD ranged between 1.77 g/cm3 and 10.27 g/cm3 and the CWC ranged from 9.1 percent to 10.3 percent. The higher amounts of SOC in CT were attributed to the annual crop residue returns while the lower amounts of SOC in the NT fields were due to grazing. Therefore, tillage influenced the amount of aggregate-associated organic carbon irrespective of the resulting size of the aggregate. The positive relationship between tillage and aggregate-associated SOC challenges the conversion of land to no-till for carbon sequestration. The overall gradient for correlation between the MBD and CWC was negative with r2 = 0.23 and a p value of 0.0076. The compressibility curves indicated higher values under CT if the texture class was silt clay.
- Full Text:
- Date Issued: 2015
Towards a framework for building security operation centers
- Authors: Jacobs, Pierre Conrad
- Date: 2015
- Subjects: Security systems industry , Systems engineering , Expert systems (Computer science) , COBIT (Information technology management standard) , Computer security
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4710 , http://hdl.handle.net/10962/d1017932
- Description: In this thesis a framework for Security Operation Centers (SOCs) is proposed. It was developed by utilising Systems Engineering best practices, combined with industry-accepted standards and frameworks, such as the TM Forum’s eTOM framework, CoBIT, ITIL, and ISO/IEC 27002:2005. This framework encompasses the design considerations, the operational considerations and the means to measure the effectiveness and efficiency of SOCs. The intent is to provide guidance to consumers on how to compare and measure the capabilities of SOCs provided by disparate service providers, and to provide service providers (internal and external) a framework to use when building and improving their offerings. The importance of providing a consistent, measureable and guaranteed service to customers is becoming more important, as there is an increased focus on holistic management of security. This has in turn resulted in an increased number of both internal and managed service provider solutions. While some frameworks exist for designing, building and operating specific security technologies used within SOCs, we did not find any comprehensive framework for designing, building and managing SOCs. Consequently, consumers of SOCs do not enjoy a constant experience from vendors, and may experience inconsistent services from geographically dispersed offerings provided by the same vendor.
- Full Text:
- Date Issued: 2015
- Authors: Jacobs, Pierre Conrad
- Date: 2015
- Subjects: Security systems industry , Systems engineering , Expert systems (Computer science) , COBIT (Information technology management standard) , Computer security
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4710 , http://hdl.handle.net/10962/d1017932
- Description: In this thesis a framework for Security Operation Centers (SOCs) is proposed. It was developed by utilising Systems Engineering best practices, combined with industry-accepted standards and frameworks, such as the TM Forum’s eTOM framework, CoBIT, ITIL, and ISO/IEC 27002:2005. This framework encompasses the design considerations, the operational considerations and the means to measure the effectiveness and efficiency of SOCs. The intent is to provide guidance to consumers on how to compare and measure the capabilities of SOCs provided by disparate service providers, and to provide service providers (internal and external) a framework to use when building and improving their offerings. The importance of providing a consistent, measureable and guaranteed service to customers is becoming more important, as there is an increased focus on holistic management of security. This has in turn resulted in an increased number of both internal and managed service provider solutions. While some frameworks exist for designing, building and operating specific security technologies used within SOCs, we did not find any comprehensive framework for designing, building and managing SOCs. Consequently, consumers of SOCs do not enjoy a constant experience from vendors, and may experience inconsistent services from geographically dispersed offerings provided by the same vendor.
- Full Text:
- Date Issued: 2015
Towards an evaluation and protection strategy for critical infrastructure
- Authors: Gottschalk, Jason Howard
- Date: 2015
- Subjects: Computer crimes -- Prevention , Computer networks -- Security measures , Computer crimes -- Law and legislation -- South Africa , Public works -- Security measures
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4721 , http://hdl.handle.net/10962/d1018793
- Description: Critical Infrastructure is often overlooked from an Information Security perspective as being of high importance to protect which may result in Critical Infrastructure being at risk to Cyber related attacks with potential dire consequences. Furthermore, what is considered Critical Infrastructure is often a complex discussion, with varying opinions across audiences. Traditional Critical Infrastructure included power stations, water, sewage pump stations, gas pipe lines, power grids and a new entrant, the “internet of things”. This list is not complete and a constant challenge exists in identifying Critical Infrastructure and its interdependencies. The purpose of this research is to highlight the importance of protecting Critical Infrastructure as well as proposing a high level framework aiding in the identification and securing of Critical Infrastructure. To achieve this, key case studies involving Cyber crime and Cyber warfare, as well as the identification of attack vectors and impact on against Critical Infrastructure (as applicable to Critical Infrastructure where possible), were identified and discussed. Furthermore industry related material was researched as to identify key controls that would aid in protecting Critical Infrastructure. The identification of initiatives that countries were pursuing, that would aid in the protection of Critical Infrastructure, were identified and discussed. Research was conducted into the various standards, frameworks and methodologies available to aid in the identification, remediation and ultimately the protection of Critical Infrastructure. A key output of the research was the development of a hybrid approach to identifying Critical Infrastructure, associated vulnerabilities and an approach for remediation with specific metrics (based on the research performed). The conclusion based on the research is that there is often a need and a requirement to identify and protect Critical Infrastructure however this is usually initiated or driven by non-owners of Critical Infrastructure (Governments, governing bodies, standards bodies and security consultants). Furthermore where there are active initiative by owners very often the suggested approaches are very high level in nature with little direct guidance available for very immature environments.
- Full Text:
- Date Issued: 2015
- Authors: Gottschalk, Jason Howard
- Date: 2015
- Subjects: Computer crimes -- Prevention , Computer networks -- Security measures , Computer crimes -- Law and legislation -- South Africa , Public works -- Security measures
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4721 , http://hdl.handle.net/10962/d1018793
- Description: Critical Infrastructure is often overlooked from an Information Security perspective as being of high importance to protect which may result in Critical Infrastructure being at risk to Cyber related attacks with potential dire consequences. Furthermore, what is considered Critical Infrastructure is often a complex discussion, with varying opinions across audiences. Traditional Critical Infrastructure included power stations, water, sewage pump stations, gas pipe lines, power grids and a new entrant, the “internet of things”. This list is not complete and a constant challenge exists in identifying Critical Infrastructure and its interdependencies. The purpose of this research is to highlight the importance of protecting Critical Infrastructure as well as proposing a high level framework aiding in the identification and securing of Critical Infrastructure. To achieve this, key case studies involving Cyber crime and Cyber warfare, as well as the identification of attack vectors and impact on against Critical Infrastructure (as applicable to Critical Infrastructure where possible), were identified and discussed. Furthermore industry related material was researched as to identify key controls that would aid in protecting Critical Infrastructure. The identification of initiatives that countries were pursuing, that would aid in the protection of Critical Infrastructure, were identified and discussed. Research was conducted into the various standards, frameworks and methodologies available to aid in the identification, remediation and ultimately the protection of Critical Infrastructure. A key output of the research was the development of a hybrid approach to identifying Critical Infrastructure, associated vulnerabilities and an approach for remediation with specific metrics (based on the research performed). The conclusion based on the research is that there is often a need and a requirement to identify and protect Critical Infrastructure however this is usually initiated or driven by non-owners of Critical Infrastructure (Governments, governing bodies, standards bodies and security consultants). Furthermore where there are active initiative by owners very often the suggested approaches are very high level in nature with little direct guidance available for very immature environments.
- Full Text:
- Date Issued: 2015
Towards large scale software based network routing simulation
- Authors: Herbert, Alan
- Date: 2015
- Subjects: Routers (Computer networks) , Computer software , Linux
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4709 , http://hdl.handle.net/10962/d1017931
- Description: Software based routing simulators suffer from large simulation host requirements and are prone to slow downs because of resource limitations, as well as context switching due to user space to kernel space requests. Furthermore, hardware based simulations do not scale with the passing of time as their available resources are set at the time of manufacture. This research aims to provide a software based, scalable solution to network simulation. It aims to achieve this by a Linux kernel-based solution, through insertion of a custom kernel module. This will reduce the number of context switches by eliminating the user space context requirement, and serve to be highly compatible with any host that can run the Linux kernel. Through careful consideration in data structure choice and software component design, this routing simulator achieved results of over 7 Gbps of throughput over multiple simulated node hops on consumer hardware. Alongside this throughput, this routing simulator also brings to light scalability and the ability to instantiate and simulate networks in excess of 1 million routing nodes within 1 GB of system memory
- Full Text:
- Date Issued: 2015
- Authors: Herbert, Alan
- Date: 2015
- Subjects: Routers (Computer networks) , Computer software , Linux
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4709 , http://hdl.handle.net/10962/d1017931
- Description: Software based routing simulators suffer from large simulation host requirements and are prone to slow downs because of resource limitations, as well as context switching due to user space to kernel space requests. Furthermore, hardware based simulations do not scale with the passing of time as their available resources are set at the time of manufacture. This research aims to provide a software based, scalable solution to network simulation. It aims to achieve this by a Linux kernel-based solution, through insertion of a custom kernel module. This will reduce the number of context switches by eliminating the user space context requirement, and serve to be highly compatible with any host that can run the Linux kernel. Through careful consideration in data structure choice and software component design, this routing simulator achieved results of over 7 Gbps of throughput over multiple simulated node hops on consumer hardware. Alongside this throughput, this routing simulator also brings to light scalability and the ability to instantiate and simulate networks in excess of 1 million routing nodes within 1 GB of system memory
- Full Text:
- Date Issued: 2015
Towards measuring corporate sustainability in the Nelson Mandela Bay automotive manufacturing sector
- Authors: Adams, Abulele
- Date: 2015
- Subjects: Sustainability -- South Africa -- Port Elizabeth Sustainable development -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/18465 , vital:28648
- Description: This study explored the methods available for measuring corporate sustainability and created an instrument to measure corporate sustainability in the Nelson Mandela Bay (NMB) automotive manufacturing sector. The instrument was created based on three components of sustainability which are environment, society and economy. The study went a step further and added a fourth dimension, current trends to design a measuring instrument. The instrument was then applied on participating companies and further refined to improve it. A total of 16 multi-dimensional indicators to measure corporate sustainability were created and applied to 12 companies in the automotive manufacturing sector. The indicators were used to create a composite corporate sustainability index which can be used to compare the corporate sustainability performance of companies. These indicators were created based on theoretical research and fist hand experience observing the automotive manufacturing sector in the NMB. The indicators were applied to companies as a pilot to test whether they are feasible. Following this, the indicators were refined, improved and applied to more companies to measure corporate sustainability performance. The results of the study were the measuring instrument created, the creation of a composite index as well as the application of the instrument on 12 companies to determine whether the instrument was refined enough to detect differences in the corporate sustainability performance of companies. The results are discussed and further recommendations are made for improvements in the creation and application of the instrument to measure corporate sustainability in the NMB automotive manufacturing sector.
- Full Text:
- Date Issued: 2015
Towards measuring corporate sustainability in the Nelson Mandela Bay automotive manufacturing sector
- Authors: Adams, Abulele
- Date: 2015
- Subjects: Sustainability -- South Africa -- Port Elizabeth Sustainable development -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/18465 , vital:28648
- Description: This study explored the methods available for measuring corporate sustainability and created an instrument to measure corporate sustainability in the Nelson Mandela Bay (NMB) automotive manufacturing sector. The instrument was created based on three components of sustainability which are environment, society and economy. The study went a step further and added a fourth dimension, current trends to design a measuring instrument. The instrument was then applied on participating companies and further refined to improve it. A total of 16 multi-dimensional indicators to measure corporate sustainability were created and applied to 12 companies in the automotive manufacturing sector. The indicators were used to create a composite corporate sustainability index which can be used to compare the corporate sustainability performance of companies. These indicators were created based on theoretical research and fist hand experience observing the automotive manufacturing sector in the NMB. The indicators were applied to companies as a pilot to test whether they are feasible. Following this, the indicators were refined, improved and applied to more companies to measure corporate sustainability performance. The results of the study were the measuring instrument created, the creation of a composite index as well as the application of the instrument on 12 companies to determine whether the instrument was refined enough to detect differences in the corporate sustainability performance of companies. The results are discussed and further recommendations are made for improvements in the creation and application of the instrument to measure corporate sustainability in the NMB automotive manufacturing sector.
- Full Text:
- Date Issued: 2015