Time-resolved luminescence from quartz: an overview of contemporary developments and applications
- Chithambo, Makaiko L, Pagonis, Vasilis, Ankjærgaard, Christina
- Authors: Chithambo, Makaiko L , Pagonis, Vasilis , Ankjærgaard, Christina
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124743 , vital:35658 , https://doi.org/10.1016/j.physb.2015.10.014
- Description: Time-resolved optical stimulation of luminescence has become established as a key method for measurement of optically stimulated luminescence from quartz, feldspar and α-Al2O3:C, all materials of interest in dosimetry. The aim of time-resolved optical stimulation is to separate in time the stimulation and emission of luminescence. The luminescence is stimulated from a sample using a brief light pulse and the emission monitored during stimulation in the presence of scattered stimulating light or after pulsing, over photomultiplier noise only. Although the use of the method in retrospective dosimetry has been somewhat limited, the technique has been successfully applied to study mechanisms in the processes leading up to luminescence emission. The main means for this has been the temperature dependence of the luminescence intensity as well as the luminescence lifetimes determined from time-resolved luminescence spectra. In this paper we review some key developments in theory and applications to quartz including methods of evaluating lifetimes, techniques of evaluating kinetic parameters using both the dependence of luminescence intensity and lifetime on measurement temperature, and of lifetimes on annealing temperature. We then provide an overview of some notable applications such as separation of quartz signals from a quartz–feldspar admixture and the utility of the dynamic throughput, a measure of luminescence measured as a function of the pulse width. The paper concludes with some suggestions of areas where further exploration would advance understanding of dynamics of luminescence in quartz and help address some outstanding problems in its application.
- Full Text: false
- Date Issued: 2016
- Authors: Chithambo, Makaiko L , Pagonis, Vasilis , Ankjærgaard, Christina
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124743 , vital:35658 , https://doi.org/10.1016/j.physb.2015.10.014
- Description: Time-resolved optical stimulation of luminescence has become established as a key method for measurement of optically stimulated luminescence from quartz, feldspar and α-Al2O3:C, all materials of interest in dosimetry. The aim of time-resolved optical stimulation is to separate in time the stimulation and emission of luminescence. The luminescence is stimulated from a sample using a brief light pulse and the emission monitored during stimulation in the presence of scattered stimulating light or after pulsing, over photomultiplier noise only. Although the use of the method in retrospective dosimetry has been somewhat limited, the technique has been successfully applied to study mechanisms in the processes leading up to luminescence emission. The main means for this has been the temperature dependence of the luminescence intensity as well as the luminescence lifetimes determined from time-resolved luminescence spectra. In this paper we review some key developments in theory and applications to quartz including methods of evaluating lifetimes, techniques of evaluating kinetic parameters using both the dependence of luminescence intensity and lifetime on measurement temperature, and of lifetimes on annealing temperature. We then provide an overview of some notable applications such as separation of quartz signals from a quartz–feldspar admixture and the utility of the dynamic throughput, a measure of luminescence measured as a function of the pulse width. The paper concludes with some suggestions of areas where further exploration would advance understanding of dynamics of luminescence in quartz and help address some outstanding problems in its application.
- Full Text: false
- Date Issued: 2016
Tourism potential as a tool for local economic development in Mnquma Local Municipality
- Authors: Mlondleni, Mzuyanda
- Date: 2016
- Subjects: Economic development -- South Africa -- Eastern Cape , Sustainable tourism -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/3095 , vital:20398
- Description: This research study aims to investigate what is there on offer for tourists in Mnquma Local Municipality, such as products (arts and craft, accommodation establishments and places of interests), their readiness for tourist consumption (state, accessibility), tourism routes and the understanding of communities on tourism and what can be derived from it to improve their livelihoods. This in turn will establish whether the tourism sector can be used as a tool for local economic development in the municipality. In the end, this study will make recommendations on what needs to be done in the municipality for the tourism sector to be more effective for the local communities and the municipality. The researcher has conducted a qualitative research study through the use of structured questionnaires as the data collection tool, in order to obtain information from specific population members of the concerned local municipality on tourism and LED issues. The study has been conducted from twenty three accommodation establishments in Mnquma Local Municipality. During the data collection period, the researcher discovered that these accommodation establishments are facing a number of challenges ranging from poor accessibility and signage for which the study is expected to address these in the recommendations. The study will include a purposive sample of tourism businesses in the hospitality sector in Mnquma Local Municipality. From the purposive sample, the researcher opted for total population sampling which is a type of purposive sampling technique where the researcher chooses to examine the entire population. At the end, researcher recommends that the municipality needs to address the infrastructural challenges such as roads (for accessibility to tourist sites), electricity and health centers to be able to support tourism economic activities. It also needs to ensure on the continuous hosting of events to address the seasonal nature of tourism and to market the municipality as an event destination. The researcher also recommended the establishment of partnerships with sector departments and parastatals such as SEDA, DTI, ECPTA, TEP etc. Lastly, being such a rural municipality with a rich history, culture and heritage, it is recommended that the municipality must prioritise tourism as a tool for Local Economic Development to better the lives of its population and to improve its economy.
- Full Text:
- Date Issued: 2016
- Authors: Mlondleni, Mzuyanda
- Date: 2016
- Subjects: Economic development -- South Africa -- Eastern Cape , Sustainable tourism -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/3095 , vital:20398
- Description: This research study aims to investigate what is there on offer for tourists in Mnquma Local Municipality, such as products (arts and craft, accommodation establishments and places of interests), their readiness for tourist consumption (state, accessibility), tourism routes and the understanding of communities on tourism and what can be derived from it to improve their livelihoods. This in turn will establish whether the tourism sector can be used as a tool for local economic development in the municipality. In the end, this study will make recommendations on what needs to be done in the municipality for the tourism sector to be more effective for the local communities and the municipality. The researcher has conducted a qualitative research study through the use of structured questionnaires as the data collection tool, in order to obtain information from specific population members of the concerned local municipality on tourism and LED issues. The study has been conducted from twenty three accommodation establishments in Mnquma Local Municipality. During the data collection period, the researcher discovered that these accommodation establishments are facing a number of challenges ranging from poor accessibility and signage for which the study is expected to address these in the recommendations. The study will include a purposive sample of tourism businesses in the hospitality sector in Mnquma Local Municipality. From the purposive sample, the researcher opted for total population sampling which is a type of purposive sampling technique where the researcher chooses to examine the entire population. At the end, researcher recommends that the municipality needs to address the infrastructural challenges such as roads (for accessibility to tourist sites), electricity and health centers to be able to support tourism economic activities. It also needs to ensure on the continuous hosting of events to address the seasonal nature of tourism and to market the municipality as an event destination. The researcher also recommended the establishment of partnerships with sector departments and parastatals such as SEDA, DTI, ECPTA, TEP etc. Lastly, being such a rural municipality with a rich history, culture and heritage, it is recommended that the municipality must prioritise tourism as a tool for Local Economic Development to better the lives of its population and to improve its economy.
- Full Text:
- Date Issued: 2016
Toward an automated botnet analysis framework: a darkcomet case-study
- Authors: du Bruyn, Jeremy Cecil
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2937 , vital:20344
- Full Text:
- Date Issued: 2016
- Authors: du Bruyn, Jeremy Cecil
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2937 , vital:20344
- Full Text:
- Date Issued: 2016
Towards an alternative spatial-based management approach for estuarine fisheries in South Africa, with a case study from the Sundays Estuary
- Authors: Kramer, Rachel
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/1007 , vital:20012
- Description: Estuaries are productive habitats and biologically important ecosystems which serve as juvenile nursery areas and feeding grounds for adults from a host of fish species. They are, however, threatened habitats, increasingly exposed to human disturbance and exploitation. The stocks of several South African estuary-dependent linefish species are now considered as either overexploited or collapsed. It is clear that their dependence on estuaries would warrant the inclusion of these ecosystems into marine reserve planning exercises. Since traditional management strategies (e.g. bag and size limit restrictions) have proven ineffective for estuarine fisheries, there is a need for alternative management measures, such as spatial and temporal restrictions, to ensure increased survival of juveniles and recovery of adult breeding populations. This thesis explored the potential for an ecosystem-based approach through the application of a rapid sustainability assessment technique, and a spatial-based management approach for an important fishery species, using conservation planning software. The Sundays Estuary, Eastern Cape, South Africa falls within the footprint of the Addo Elephant National Park, with a proposed expansion to include a marine protected area (MPA). However the estuaries resources were not considered during the planning of the proposed MPA. This study conducted an indicator-based sustainability assessment based on the principles of sustainable development. The results showed that present levels of exploitation, due to non-compliance and a lack of law enforcement are unsustainable. The sustainability of the Sundays Estuary had a low overall sustainability score of only 23.8%. With limited enforcement of estuarine fisheries regulations in South Africa, alternative management measures such as spatial regulations may provide a viable option forward. The sustainability of fishery resources depends on the comprehensive understanding of the fishery resource. Acoustic telemetry is a technique that has been widely adopted to infer habitat and area use patterns of fish species. The second component of this study made use of high resolution telemetry data collected on juvenile dusky kob Argyrosomus japonicus movements within the Sundays Estuary to conduct a scenario-based approach using Marxan conservation planning software. The best solution given by Marxan, in the form of a protected area for the conservation of juvenile A. japonicus in the Sundays Estuary was identified in the middle (starting 7km from the mouth) to the upper reaches (approximately 16km from the mouth) of the estuary, ultimately providing protection to tagged individuals for 61% of their time in the estuary. Although Marxan presented a best solution, the Sundays Estuary’s small size and shape, and minimal features used, was too simplistic to be included into a Marxan analysis. However, new methods and tools to analyse and plan spatial-based management options at this scale are currently being developed. Using the Sundays Estuary as a case study, a decision tree was then developed as a protocol to assist management address the challenges of effective estuarine management depending on the unique biological and socio-economic characteristics of individual estuaries in South Africa.
- Full Text:
- Date Issued: 2016
- Authors: Kramer, Rachel
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/1007 , vital:20012
- Description: Estuaries are productive habitats and biologically important ecosystems which serve as juvenile nursery areas and feeding grounds for adults from a host of fish species. They are, however, threatened habitats, increasingly exposed to human disturbance and exploitation. The stocks of several South African estuary-dependent linefish species are now considered as either overexploited or collapsed. It is clear that their dependence on estuaries would warrant the inclusion of these ecosystems into marine reserve planning exercises. Since traditional management strategies (e.g. bag and size limit restrictions) have proven ineffective for estuarine fisheries, there is a need for alternative management measures, such as spatial and temporal restrictions, to ensure increased survival of juveniles and recovery of adult breeding populations. This thesis explored the potential for an ecosystem-based approach through the application of a rapid sustainability assessment technique, and a spatial-based management approach for an important fishery species, using conservation planning software. The Sundays Estuary, Eastern Cape, South Africa falls within the footprint of the Addo Elephant National Park, with a proposed expansion to include a marine protected area (MPA). However the estuaries resources were not considered during the planning of the proposed MPA. This study conducted an indicator-based sustainability assessment based on the principles of sustainable development. The results showed that present levels of exploitation, due to non-compliance and a lack of law enforcement are unsustainable. The sustainability of the Sundays Estuary had a low overall sustainability score of only 23.8%. With limited enforcement of estuarine fisheries regulations in South Africa, alternative management measures such as spatial regulations may provide a viable option forward. The sustainability of fishery resources depends on the comprehensive understanding of the fishery resource. Acoustic telemetry is a technique that has been widely adopted to infer habitat and area use patterns of fish species. The second component of this study made use of high resolution telemetry data collected on juvenile dusky kob Argyrosomus japonicus movements within the Sundays Estuary to conduct a scenario-based approach using Marxan conservation planning software. The best solution given by Marxan, in the form of a protected area for the conservation of juvenile A. japonicus in the Sundays Estuary was identified in the middle (starting 7km from the mouth) to the upper reaches (approximately 16km from the mouth) of the estuary, ultimately providing protection to tagged individuals for 61% of their time in the estuary. Although Marxan presented a best solution, the Sundays Estuary’s small size and shape, and minimal features used, was too simplistic to be included into a Marxan analysis. However, new methods and tools to analyse and plan spatial-based management options at this scale are currently being developed. Using the Sundays Estuary as a case study, a decision tree was then developed as a protocol to assist management address the challenges of effective estuarine management depending on the unique biological and socio-economic characteristics of individual estuaries in South Africa.
- Full Text:
- Date Issued: 2016
Towards an industrial ecology for the Nelson Mandela Bay: Metropolitan area
- Authors: Dalindyebo, Litha
- Date: 2016
- Subjects: Industrial ecology -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/9263 , vital:26556
- Description: The aim of this study is to formulate a model of industrial ecology for wider application in the Nelson Mandel Bay (NMB) Metropole. To achieve this aim, the following objectives will be pursued: • A theoretical investigation of the concept of industrial ecology – in an attempt to establish its meaning, as well as the implications thereof. • A theoretical investigation of the operational implications of industrial ecology, including existing methodologies, such as Material Flow Analysis (MFA) and Life Cycle Assessment (LCA) that can be applied, in order to develop a system of industrial ecology between different companies. • The formulation of a methodology for application to the case study. • Presenting and discussing the research results produced by the application of the industrial ecology related methodology to the case study. • To present a synthesis of the research results of this study. This objective includes a critical evaluation of the research methodology and results, as well as some recommendations for the facilitation of industrial ecology. The methodology of the research involved conducting semi structured interviews, conducting a Material Flow Analysis and Life Cycle Analysis using SIMAPRO software. There interview with Goodyear management took place (see Appendix A), while the management at Sovereign Foods agreed to an interview however they didn’t honour the agreement. During the interview at Goodyear understanding of the operational process was achieved by conducting the interviews. The three areas that were discussed during the interview process were: 1. How the boiler works; 2. Current Air-Emission results; and 3. The process of steam generation. An MFA and an LCA on the production process of comparing the boiler functionality was conducted, so that there is an adequate understanding of the environmental performance of the two different boilers. The results of the MFA are presented as follows, namely: the goal and scope definition and the inventory results. Coal boiler versus fluidised boiler data where modelled. The modelling is done on comparing the flow of chemicals during steam production process, and which chemicals have a significant environmental impact. The LCA results looked at the basis of the symbiotic approach by identifying sustainable choices of design, production and consumption. The findings of this research have been obtained from the investigation of industrial ecology framework planning at Goodyear SA and Sovereign Foods. The findings have revealed that there is a synergy that exists between the two case-study areas. However, this is based on Goodyear changing the technology of the boiler they use (a boiler creates steam for the tyre-building process). The company will be required to use a fluidised boiler, instead of the current coal boiler. The use of the fluidised boiler will ensure that all waste streams at Goodyear will be reused and recycled, thereby creating the framework for industrial ecology. The results that are firstly drawn out of SIMAPRO is the Life Cycle Inventory. In this research, there is a flow of 1437 chemical materials and substances in the production of steam using both coal boiler and fluidized boiler. Due to the number of substance flow elements, the research has presented only the significant substances that influence the environmental performance of steam production using the two different feeder materials, which are coal and chicken matter (see Figure 4.4). In the coal boiler process, sulfur comprises the largest amount of chemical substance. The other top five chemical components that contribute to the steam production process are: nickel, chromium, arsenic and iodosulfuron-methyl-sodium. The scale of figure 4.4 is reduced to show the various number of chemical flows found in the steam production process through SIMAPRO software. The Life Cycle Assessment (LCA) results were presented looking at namely the following characterization, normalization, weighting, single score and damage assessment (see Figure 4.7 – 4.10 p87 – p90). The figures are presented as taken directly from the reports drawn from the SIMAPRO software. Figure 4.7 gives the characterisation results up to 100%, where 0% has a minimal environmental effect; whereas 100% has the most significant environmental effect. Oxidation of coal is compared versus the oxidation of chicken matter, the coal boiler process has higher environmental impacts. Figure 4.8 shows the normalisation results of the coal boiler versus the fluidised boiler for the functional unit steam production. The environmental degradation under normalisation between the two boilers are measured, based on three parameters, namely: human health, ecosystems and resources. In all three parameters that are measured under normalisation, the production of steam using the coal boiler has the highest impacts. The weighting results in Figure 4.9 show a mirror image of the normalisation results. Finally, a gap analysis of the theoretical requirements for industrial ecology is displayed versus what currently exists in the case study area. The gap analysis will assist in the development of recommendations. These will be presented in the next chapter. A gap analysis of findings is discussed leading into the synthesis. The value of this research is that the baseline data of planning for an industrial ecology create a platform that can be used for implementing an industrial ecology between Goodyear SA and Sovereign Foods. This will, in time, have wider applications for the entire NMB metropole.
- Full Text:
- Date Issued: 2016
- Authors: Dalindyebo, Litha
- Date: 2016
- Subjects: Industrial ecology -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/9263 , vital:26556
- Description: The aim of this study is to formulate a model of industrial ecology for wider application in the Nelson Mandel Bay (NMB) Metropole. To achieve this aim, the following objectives will be pursued: • A theoretical investigation of the concept of industrial ecology – in an attempt to establish its meaning, as well as the implications thereof. • A theoretical investigation of the operational implications of industrial ecology, including existing methodologies, such as Material Flow Analysis (MFA) and Life Cycle Assessment (LCA) that can be applied, in order to develop a system of industrial ecology between different companies. • The formulation of a methodology for application to the case study. • Presenting and discussing the research results produced by the application of the industrial ecology related methodology to the case study. • To present a synthesis of the research results of this study. This objective includes a critical evaluation of the research methodology and results, as well as some recommendations for the facilitation of industrial ecology. The methodology of the research involved conducting semi structured interviews, conducting a Material Flow Analysis and Life Cycle Analysis using SIMAPRO software. There interview with Goodyear management took place (see Appendix A), while the management at Sovereign Foods agreed to an interview however they didn’t honour the agreement. During the interview at Goodyear understanding of the operational process was achieved by conducting the interviews. The three areas that were discussed during the interview process were: 1. How the boiler works; 2. Current Air-Emission results; and 3. The process of steam generation. An MFA and an LCA on the production process of comparing the boiler functionality was conducted, so that there is an adequate understanding of the environmental performance of the two different boilers. The results of the MFA are presented as follows, namely: the goal and scope definition and the inventory results. Coal boiler versus fluidised boiler data where modelled. The modelling is done on comparing the flow of chemicals during steam production process, and which chemicals have a significant environmental impact. The LCA results looked at the basis of the symbiotic approach by identifying sustainable choices of design, production and consumption. The findings of this research have been obtained from the investigation of industrial ecology framework planning at Goodyear SA and Sovereign Foods. The findings have revealed that there is a synergy that exists between the two case-study areas. However, this is based on Goodyear changing the technology of the boiler they use (a boiler creates steam for the tyre-building process). The company will be required to use a fluidised boiler, instead of the current coal boiler. The use of the fluidised boiler will ensure that all waste streams at Goodyear will be reused and recycled, thereby creating the framework for industrial ecology. The results that are firstly drawn out of SIMAPRO is the Life Cycle Inventory. In this research, there is a flow of 1437 chemical materials and substances in the production of steam using both coal boiler and fluidized boiler. Due to the number of substance flow elements, the research has presented only the significant substances that influence the environmental performance of steam production using the two different feeder materials, which are coal and chicken matter (see Figure 4.4). In the coal boiler process, sulfur comprises the largest amount of chemical substance. The other top five chemical components that contribute to the steam production process are: nickel, chromium, arsenic and iodosulfuron-methyl-sodium. The scale of figure 4.4 is reduced to show the various number of chemical flows found in the steam production process through SIMAPRO software. The Life Cycle Assessment (LCA) results were presented looking at namely the following characterization, normalization, weighting, single score and damage assessment (see Figure 4.7 – 4.10 p87 – p90). The figures are presented as taken directly from the reports drawn from the SIMAPRO software. Figure 4.7 gives the characterisation results up to 100%, where 0% has a minimal environmental effect; whereas 100% has the most significant environmental effect. Oxidation of coal is compared versus the oxidation of chicken matter, the coal boiler process has higher environmental impacts. Figure 4.8 shows the normalisation results of the coal boiler versus the fluidised boiler for the functional unit steam production. The environmental degradation under normalisation between the two boilers are measured, based on three parameters, namely: human health, ecosystems and resources. In all three parameters that are measured under normalisation, the production of steam using the coal boiler has the highest impacts. The weighting results in Figure 4.9 show a mirror image of the normalisation results. Finally, a gap analysis of the theoretical requirements for industrial ecology is displayed versus what currently exists in the case study area. The gap analysis will assist in the development of recommendations. These will be presented in the next chapter. A gap analysis of findings is discussed leading into the synthesis. The value of this research is that the baseline data of planning for an industrial ecology create a platform that can be used for implementing an industrial ecology between Goodyear SA and Sovereign Foods. This will, in time, have wider applications for the entire NMB metropole.
- Full Text:
- Date Issued: 2016
Towards determining the dietary lysine requirement in the South African abalone, Haliotis midae
- Authors: Lloyd, Kyle Everett
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/1024 , vital:20014
- Description: Animals generally do not have a requirement for protein, but instead have a requirement for specific essential amino acids (EAAs) and non-essential amino acids (NEAAs). The NEAAs are those that can be synthesised by the animal, however, EAAs cannot be synthesised and must therefore be supplied as part of the diet. When these amino acids (AAs) are supplied in the correct ratios and with the correct level of digestible energy, nutritionists can maximise somatic growth from proteins. This has resulted in increased research into the use of crystalline AAs as a tool in feed formulation research in order to quantify the AA requirements in aquaculture species, and allow for alternative protein sources (other than fishmeal) to be utilised. In common with other water soluble nutrients, leaching of crystalline AAs from diets prior to ingestion is of concern in an aquatic environment. Microencapsulation techniques have been successfully employed to restrict micronutrient leaching, and improve ingestion rates. In this research, LysiPEARL™ (Kemin®) was used as a means to determine the lysine requirement in Haliotis. midae. This encapsulated lysine product is used in the dairy cattle industry as an effective source of rumen bypass for intestinal release of lysine. It has previously been proposed that crystalline AAs are not suitable for AA studies in H. midae due to the slow feeding rates of the species as well as the solubility of these AAs. However, 90.00 % of supplemented lysine was maintained in this study after a six hour period of leaching, showing that if effective microencapsulation techniques are used, it is possible to use crystalline amino acids to supplement protein bound lysine in abalone feeds. Six isoenergetic (15.90 MJ/kg), isolipidic (6.00 %) and isonitrogenous (29.00 %) diets enriched with 5.52, 6.40, 7.28, 8.14, 9.00 and 9.86 % lysine (as a % of protein) were fed to triplicate groups of 20 H. midae (20.41 ± 1.95 mm SL 1.51 ± 0.44 g w.wt) for 90 days. Wet weight and shell length measurements were taken every 30 days and specific growth rate (SGR) (% body weight.day-1), feed conversion ratio (FCR), protein efficiency ratio (PER), feed consumption (% body weight.day-1) and condition factor were calculated for each dietary treatment. Linear regression showed that FCR increased as dietary lysine increased (Regression analysis, p=0.031), and that PER reduced as dietary lysine increased (Regression analysis, p=0.026). Feed consumption also increased as dietary lysine increased (Regression analysis, p<0.001). The inclusion of lysine at 7.28 % of the total protein in the diet resulted in significantly superior SGR (0.57±0.01 % body weight.day-1) to that of 5.52 % (0.42±0.05 % body weight.day-1), FCR (1.51±0.05) to that of 8.14 % (1.99±0.21) and PER (2.45±0.07) to that of 8.14 % (1.99±0.18; ANOVA, p<0.05). There was a significant difference found in feed consumption (% body wt.d-1), with consumption increasing significantly between the first three dietary treatments and the last three dietary treatments (ANOVA, p<0.001). There was no significant improvement in SGR when dietary lysine increased above 7.28 % of the dietary protein in the diet, indicating that dietary lysine requirement was being met at 7.28 %, after which excess lysine promoted no growth response. The diet producing the best SGR, PER and FCR in this study was diet 3 which had a measured lysine content of 6.90 %. The results of the present study suggest that the lysine requirement in H. midae is in the range of 6.00 - 7.00 % of dietary protein. From these data amino acid ratios were used to estimate optimum inclusion levels of other essential amino acids. However, lysine availability in LysiPEARL™ may have resulted in over estimations due to the lipid encapsulation technique used, and haliotids limited ability to efficiently digest lipids. For this reason EAA requirements were suggested based on three different hypothetical scenarios of lysine availability from LysiPEARL™.
- Full Text:
- Date Issued: 2016
- Authors: Lloyd, Kyle Everett
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/1024 , vital:20014
- Description: Animals generally do not have a requirement for protein, but instead have a requirement for specific essential amino acids (EAAs) and non-essential amino acids (NEAAs). The NEAAs are those that can be synthesised by the animal, however, EAAs cannot be synthesised and must therefore be supplied as part of the diet. When these amino acids (AAs) are supplied in the correct ratios and with the correct level of digestible energy, nutritionists can maximise somatic growth from proteins. This has resulted in increased research into the use of crystalline AAs as a tool in feed formulation research in order to quantify the AA requirements in aquaculture species, and allow for alternative protein sources (other than fishmeal) to be utilised. In common with other water soluble nutrients, leaching of crystalline AAs from diets prior to ingestion is of concern in an aquatic environment. Microencapsulation techniques have been successfully employed to restrict micronutrient leaching, and improve ingestion rates. In this research, LysiPEARL™ (Kemin®) was used as a means to determine the lysine requirement in Haliotis. midae. This encapsulated lysine product is used in the dairy cattle industry as an effective source of rumen bypass for intestinal release of lysine. It has previously been proposed that crystalline AAs are not suitable for AA studies in H. midae due to the slow feeding rates of the species as well as the solubility of these AAs. However, 90.00 % of supplemented lysine was maintained in this study after a six hour period of leaching, showing that if effective microencapsulation techniques are used, it is possible to use crystalline amino acids to supplement protein bound lysine in abalone feeds. Six isoenergetic (15.90 MJ/kg), isolipidic (6.00 %) and isonitrogenous (29.00 %) diets enriched with 5.52, 6.40, 7.28, 8.14, 9.00 and 9.86 % lysine (as a % of protein) were fed to triplicate groups of 20 H. midae (20.41 ± 1.95 mm SL 1.51 ± 0.44 g w.wt) for 90 days. Wet weight and shell length measurements were taken every 30 days and specific growth rate (SGR) (% body weight.day-1), feed conversion ratio (FCR), protein efficiency ratio (PER), feed consumption (% body weight.day-1) and condition factor were calculated for each dietary treatment. Linear regression showed that FCR increased as dietary lysine increased (Regression analysis, p=0.031), and that PER reduced as dietary lysine increased (Regression analysis, p=0.026). Feed consumption also increased as dietary lysine increased (Regression analysis, p<0.001). The inclusion of lysine at 7.28 % of the total protein in the diet resulted in significantly superior SGR (0.57±0.01 % body weight.day-1) to that of 5.52 % (0.42±0.05 % body weight.day-1), FCR (1.51±0.05) to that of 8.14 % (1.99±0.21) and PER (2.45±0.07) to that of 8.14 % (1.99±0.18; ANOVA, p<0.05). There was a significant difference found in feed consumption (% body wt.d-1), with consumption increasing significantly between the first three dietary treatments and the last three dietary treatments (ANOVA, p<0.001). There was no significant improvement in SGR when dietary lysine increased above 7.28 % of the dietary protein in the diet, indicating that dietary lysine requirement was being met at 7.28 %, after which excess lysine promoted no growth response. The diet producing the best SGR, PER and FCR in this study was diet 3 which had a measured lysine content of 6.90 %. The results of the present study suggest that the lysine requirement in H. midae is in the range of 6.00 - 7.00 % of dietary protein. From these data amino acid ratios were used to estimate optimum inclusion levels of other essential amino acids. However, lysine availability in LysiPEARL™ may have resulted in over estimations due to the lipid encapsulation technique used, and haliotids limited ability to efficiently digest lipids. For this reason EAA requirements were suggested based on three different hypothetical scenarios of lysine availability from LysiPEARL™.
- Full Text:
- Date Issued: 2016
Trade liberalisation, the real exchange rate and sectoral employment : a case study of South Africa
- Authors: Sibanda, Kin
- Date: 2016
- Subjects: Foreign exchange rates Employment (Economic theory) Free trade -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/12777 , vital:39360
- Description: This study examined the relationship between trade liberalisation, the real exchange rate and sectoral employment in South Africa for the period 1994 to 2014. Firstly, using quarterly time series data, the Autoregressive Distributed Lag (ARDL) technique was employed to formally check if South African real exchange rates are responsive to trade liberalisation. This was done to see if trade liberalisation impacts real exchange rates in South Africa, to the extent that they cannot be controlled concurrently in the subsequent models. Based on the ARDL results, trade liberalisation does not have a significant effect on the exchange rate. However, when the real exchange rate is an independent variable of trade liberalisation, the results show that real exchange rates affect trade, specifically the export propensity index. The next step was to assess the impact of trade liberalisation and real exchange rate on sectoral employment using quarterly panel data for South Africa from 1994 to 2014 controlling for both sector-specific and macro-economic variables. The study employed diverse panel data analysis techniques to separate the sectoral effects, starting with broad sectors followed by the disaggregated sectors, to identify the sectors most affected by real exchange rates and trade liberalisation. The Generalised method of Moments (GMM) results reveal that a unit increase in exchange rate (implying appreciation), causes employment to go down by about 9 percent in South Africa. The same relationship is depicted from the Pooled Mean Group (PMG) estimations in both the short run and long run. Random coefficients (betas) show that the real exchange rate negatively affects the primary and secondary sector with a positive but insignificant effect on the tertiary sector. The sub-sectors negatively hit hard by real exchange rates are communication, mining and transport. The results also show that trade liberalisation is linked to both job destruction and job creation. The static models reveal that trade openness has a statistically positive and significant impact on employment in the short run while the PMG estimator results show that the effect is negative and only significant in the short run. The dynamic models (GMM and PMG) showed trade liberalisation (as proxied by trade openness and import propensity) has a statistical and significantly positive short run impact on employment. This implies that selective trade liberalisation strategies are needed in order for South Africa to maximise the gains from trade.
- Full Text:
- Date Issued: 2016
- Authors: Sibanda, Kin
- Date: 2016
- Subjects: Foreign exchange rates Employment (Economic theory) Free trade -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/12777 , vital:39360
- Description: This study examined the relationship between trade liberalisation, the real exchange rate and sectoral employment in South Africa for the period 1994 to 2014. Firstly, using quarterly time series data, the Autoregressive Distributed Lag (ARDL) technique was employed to formally check if South African real exchange rates are responsive to trade liberalisation. This was done to see if trade liberalisation impacts real exchange rates in South Africa, to the extent that they cannot be controlled concurrently in the subsequent models. Based on the ARDL results, trade liberalisation does not have a significant effect on the exchange rate. However, when the real exchange rate is an independent variable of trade liberalisation, the results show that real exchange rates affect trade, specifically the export propensity index. The next step was to assess the impact of trade liberalisation and real exchange rate on sectoral employment using quarterly panel data for South Africa from 1994 to 2014 controlling for both sector-specific and macro-economic variables. The study employed diverse panel data analysis techniques to separate the sectoral effects, starting with broad sectors followed by the disaggregated sectors, to identify the sectors most affected by real exchange rates and trade liberalisation. The Generalised method of Moments (GMM) results reveal that a unit increase in exchange rate (implying appreciation), causes employment to go down by about 9 percent in South Africa. The same relationship is depicted from the Pooled Mean Group (PMG) estimations in both the short run and long run. Random coefficients (betas) show that the real exchange rate negatively affects the primary and secondary sector with a positive but insignificant effect on the tertiary sector. The sub-sectors negatively hit hard by real exchange rates are communication, mining and transport. The results also show that trade liberalisation is linked to both job destruction and job creation. The static models reveal that trade openness has a statistically positive and significant impact on employment in the short run while the PMG estimator results show that the effect is negative and only significant in the short run. The dynamic models (GMM and PMG) showed trade liberalisation (as proxied by trade openness and import propensity) has a statistical and significantly positive short run impact on employment. This implies that selective trade liberalisation strategies are needed in order for South Africa to maximise the gains from trade.
- Full Text:
- Date Issued: 2016
Traditional and cultural practices and the rights of women : a study of widowhood practices among the Akans in Ghana
- Authors: Afari-Twumasi, Lucy
- Date: 2016
- Subjects: Widows -- Legal status, laws, etc. -- Ghana Widowhood -- Ghana Akan (African people) -- Social life and customs
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: http://hdl.handle.net/10353/2844 , vital:28106
- Description: The study investigates the human rights violations that underlie widowhood practices in Cape Coast and Komenda in the Central Region of Ghana. Review of the relevant literature on widowhood practices suggests that widowhood practices are a global cultural phenomenon, which is not confined to Sub-Sahara Africa. A survey of relevant studies on the phenomenon suggests that there are two competing perceptions on African widowhood practices: (1) a dominant negative perspective and (2) a minor positive perspective. The dominant negative perspective, which receives overwhelming research attention, focuses only on the negative characteristics of widowhood while the minor positive perspective which receives scanty research attention, rejects the criticisms levelled against widowhood practices as being externally influenced by Christianity and Western Feminism. Various stakeholders within the Akan community were given an opportunity to retell their own versions of widowhood practices. In order to achieve this purpose, the research extracted competing narratives from all the multiple sample subgroups of the proposed study: widows; widow family heads; chiefs; widowhood ritual practitioners; elderly female supervisors of widowhood practices; an official from the Commission for Human Rights and Administrative Justice (CHRAJ); an official from the Ministry of Women and Children Affairs (MOWAC); and an official from the Domestic Violence and Victims Support Unit (DOVVSU) of Ghana. The study found out that despite legislative intervention and policy frameworks, the practice still persist among the Akan communities in Ghana. The reasons for the continued existence of such rituals are explained followed by recommendations for possible solutions.
- Full Text:
- Date Issued: 2016
- Authors: Afari-Twumasi, Lucy
- Date: 2016
- Subjects: Widows -- Legal status, laws, etc. -- Ghana Widowhood -- Ghana Akan (African people) -- Social life and customs
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: http://hdl.handle.net/10353/2844 , vital:28106
- Description: The study investigates the human rights violations that underlie widowhood practices in Cape Coast and Komenda in the Central Region of Ghana. Review of the relevant literature on widowhood practices suggests that widowhood practices are a global cultural phenomenon, which is not confined to Sub-Sahara Africa. A survey of relevant studies on the phenomenon suggests that there are two competing perceptions on African widowhood practices: (1) a dominant negative perspective and (2) a minor positive perspective. The dominant negative perspective, which receives overwhelming research attention, focuses only on the negative characteristics of widowhood while the minor positive perspective which receives scanty research attention, rejects the criticisms levelled against widowhood practices as being externally influenced by Christianity and Western Feminism. Various stakeholders within the Akan community were given an opportunity to retell their own versions of widowhood practices. In order to achieve this purpose, the research extracted competing narratives from all the multiple sample subgroups of the proposed study: widows; widow family heads; chiefs; widowhood ritual practitioners; elderly female supervisors of widowhood practices; an official from the Commission for Human Rights and Administrative Justice (CHRAJ); an official from the Ministry of Women and Children Affairs (MOWAC); and an official from the Domestic Violence and Victims Support Unit (DOVVSU) of Ghana. The study found out that despite legislative intervention and policy frameworks, the practice still persist among the Akan communities in Ghana. The reasons for the continued existence of such rituals are explained followed by recommendations for possible solutions.
- Full Text:
- Date Issued: 2016
Transcription factor motif quality assessment requires systematic comparative analysis [version 2; referees: 2 approved]
- Kibet, Caleb K, Machanick, Philip
- Authors: Kibet, Caleb K , Machanick, Philip
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61169 , vital:27987 , http://dx.doi.org/10.12688/f1000research.7408.2
- Description: Transcription factor (TF) binding site prediction remains a challenge in gene regulatory research due to degeneracy and potential variability in binding sites in the genome. Dozens of algorithms designed to learn binding models (motifs) have generated many motifs available in research papers with a subset making it to databases like JASPAR, UniPROBE and Transfac. The presence of many versions of motifs from the various databases for a single TF and the lack of a standardized assessment technique makes it difficult for biologists to make an appropriate choice of binding model and for algorithm developers to benchmark, test and improve on their models. In this study, we review and evaluate the approaches in use, highlight differences and demonstrate the difficulty of defining a standardized motif assessment approach. We review scoring functions, motif length, test data and the type of performance metrics used in prior studies as some of the factors that influence the outcome of a motif assessment. We show that the scoring functions and statistics used in motif assessment influence ranking of motifs in a TF-specific manner. We also show that TF binding specificity can vary by source of genomic binding data. We also demonstrate that information content of a motif is not in isolation a measure of motif quality but is influenced by TF binding behaviour. We conclude that there is a need for an easy-to-use tool that presents all available evidence for a comparative analysis.
- Full Text:
- Date Issued: 2016
- Authors: Kibet, Caleb K , Machanick, Philip
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61169 , vital:27987 , http://dx.doi.org/10.12688/f1000research.7408.2
- Description: Transcription factor (TF) binding site prediction remains a challenge in gene regulatory research due to degeneracy and potential variability in binding sites in the genome. Dozens of algorithms designed to learn binding models (motifs) have generated many motifs available in research papers with a subset making it to databases like JASPAR, UniPROBE and Transfac. The presence of many versions of motifs from the various databases for a single TF and the lack of a standardized assessment technique makes it difficult for biologists to make an appropriate choice of binding model and for algorithm developers to benchmark, test and improve on their models. In this study, we review and evaluate the approaches in use, highlight differences and demonstrate the difficulty of defining a standardized motif assessment approach. We review scoring functions, motif length, test data and the type of performance metrics used in prior studies as some of the factors that influence the outcome of a motif assessment. We show that the scoring functions and statistics used in motif assessment influence ranking of motifs in a TF-specific manner. We also show that TF binding specificity can vary by source of genomic binding data. We also demonstrate that information content of a motif is not in isolation a measure of motif quality but is influenced by TF binding behaviour. We conclude that there is a need for an easy-to-use tool that presents all available evidence for a comparative analysis.
- Full Text:
- Date Issued: 2016
Transforming the use of tutorials through academic staff development
- Clarence, Sherran, Wolff, Karin, Winberg, Simon, Farmer, Jean-Lee, Esambe, Emmanuel
- Authors: Clarence, Sherran , Wolff, Karin , Winberg, Simon , Farmer, Jean-Lee , Esambe, Emmanuel
- Date: 2016
- Language: English
- Type: text , conference publication
- Identifier: http://hdl.handle.net/10962/66982 , vital:29008
- Full Text:
- Date Issued: 2016
- Authors: Clarence, Sherran , Wolff, Karin , Winberg, Simon , Farmer, Jean-Lee , Esambe, Emmanuel
- Date: 2016
- Language: English
- Type: text , conference publication
- Identifier: http://hdl.handle.net/10962/66982 , vital:29008
- Full Text:
- Date Issued: 2016
Transitions into informal employment: an analysis of South African panel data: 2008-2012
- Authors: Muttze, Takudzwa
- Date: 2016
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: http://hdl.handle.net/10962/4498 , vital:20682
- Description: South Africa’s labour market is characterised by high unemployment but relatively low levels of informal employment, making it distinct from other developing countries. The existing literature appears to show evidence of high mobility rates of labour across labour market states. The coexistence of high labour mobility rates, yet high unemployment and weak informal employment in South Africa’s labour market is therefore puzzling. Considerable research has been done to explain this phenomenon and has suggested that barriers to informal entrepreneurship form the key reason why informal employment is relatively low in South Africa compared to other developing countries. Worker transitions have however not been a focal question in the literature. Using data from the National Tncome Dynamics Study (NTDS 2008-2012), this study sought to examine the characteristics of workers who move into informal employment, attaching importance to those who become self-employed. Transition matrices are constructed showing the proportion of workers who stayed or moved into different labour market states between 2008 and 2012, and linking the movements to 2008 personal characteristics. Churning between labour market states was found to be relatively high, albeit formal wage employment exhibiting immobility. Transitions out of informal employment were high, reflecting its survivalist nature. Conversely, those from unemployment into informal employment, particularly self-employment were low. Using the probit regression model, transitions to informal employment were found to be more associated with workers who are generally marginalised from formal employment opportunities. The results suggest that the South African labour market is to a larger extent not reflective of the Dualist narrative of ease of movement of workers from unemployment into informal employment and barriers into informal entrepreneurship are high. To date, policies which have sought to encourage informal entrepreneurship have not been a success. A central challenge to policymakers is to create an enabling environment for the unemployed to start their own informal businesses. This has the potential of reducing unemployment and poverty rates in the country.
- Full Text:
- Date Issued: 2016
- Authors: Muttze, Takudzwa
- Date: 2016
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: http://hdl.handle.net/10962/4498 , vital:20682
- Description: South Africa’s labour market is characterised by high unemployment but relatively low levels of informal employment, making it distinct from other developing countries. The existing literature appears to show evidence of high mobility rates of labour across labour market states. The coexistence of high labour mobility rates, yet high unemployment and weak informal employment in South Africa’s labour market is therefore puzzling. Considerable research has been done to explain this phenomenon and has suggested that barriers to informal entrepreneurship form the key reason why informal employment is relatively low in South Africa compared to other developing countries. Worker transitions have however not been a focal question in the literature. Using data from the National Tncome Dynamics Study (NTDS 2008-2012), this study sought to examine the characteristics of workers who move into informal employment, attaching importance to those who become self-employed. Transition matrices are constructed showing the proportion of workers who stayed or moved into different labour market states between 2008 and 2012, and linking the movements to 2008 personal characteristics. Churning between labour market states was found to be relatively high, albeit formal wage employment exhibiting immobility. Transitions out of informal employment were high, reflecting its survivalist nature. Conversely, those from unemployment into informal employment, particularly self-employment were low. Using the probit regression model, transitions to informal employment were found to be more associated with workers who are generally marginalised from formal employment opportunities. The results suggest that the South African labour market is to a larger extent not reflective of the Dualist narrative of ease of movement of workers from unemployment into informal employment and barriers into informal entrepreneurship are high. To date, policies which have sought to encourage informal entrepreneurship have not been a success. A central challenge to policymakers is to create an enabling environment for the unemployed to start their own informal businesses. This has the potential of reducing unemployment and poverty rates in the country.
- Full Text:
- Date Issued: 2016
Trends in the game industry in the Eastern Cape
- Authors: Ferreira, Janene
- Date: 2016
- Subjects: Game farms -- South Africa -- Eastern Cape -- Management , Wildlife management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/5451 , vital:20846
- Description: The game industry has become one of the fastest-growing industries in South Africa and consequently, during recent years, a growing number of stock farms have been converted to game farms. All forms of utilization within the game industry play a vital role with regards to sustainability and simultaneously contributing a significant boost to the national economy. It is therefore important to ensure that game ranchers are as well-informed as possible in their decision-making, as well as in assessing their outputs and endeavours. However, the information available on the game industry in the Eastern Cape is limited. This research study therefore focuses on the emerging trends in the game industry in the province. The objectives of the research are to examine various pertinent factors associated with the game industry, investigate the trends and discuss whether these trends have any implications for future purposes. The research commenced with a literature review, as well as information from earlier survey studies of the Eastern Cape game industry. For the current study, a replicate survey was conducted throughout the Eastern Cape, involving as many game ranchers as possible, and data were collected by means of self-administered questionnaires. The dilemma confronting the black wildebeest in the Eastern Cape was thoroughly investigated, together with farmers’ opinions and trends for the future of the species. It was important to include this particular aspect in the research, as at the time of the survey, widespread concerns were expressed with regards to new legislation which emerged during that time. The research cast light on several aspects associated with the industry which could positively assist game ranchers towards improved management and planning, as well as provide guidelines for future development purposes. Furthermore, the research identified crucial issues that should receive immediate attention from stakeholders across the industry as well as government.
- Full Text:
- Date Issued: 2016
- Authors: Ferreira, Janene
- Date: 2016
- Subjects: Game farms -- South Africa -- Eastern Cape -- Management , Wildlife management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/5451 , vital:20846
- Description: The game industry has become one of the fastest-growing industries in South Africa and consequently, during recent years, a growing number of stock farms have been converted to game farms. All forms of utilization within the game industry play a vital role with regards to sustainability and simultaneously contributing a significant boost to the national economy. It is therefore important to ensure that game ranchers are as well-informed as possible in their decision-making, as well as in assessing their outputs and endeavours. However, the information available on the game industry in the Eastern Cape is limited. This research study therefore focuses on the emerging trends in the game industry in the province. The objectives of the research are to examine various pertinent factors associated with the game industry, investigate the trends and discuss whether these trends have any implications for future purposes. The research commenced with a literature review, as well as information from earlier survey studies of the Eastern Cape game industry. For the current study, a replicate survey was conducted throughout the Eastern Cape, involving as many game ranchers as possible, and data were collected by means of self-administered questionnaires. The dilemma confronting the black wildebeest in the Eastern Cape was thoroughly investigated, together with farmers’ opinions and trends for the future of the species. It was important to include this particular aspect in the research, as at the time of the survey, widespread concerns were expressed with regards to new legislation which emerged during that time. The research cast light on several aspects associated with the industry which could positively assist game ranchers towards improved management and planning, as well as provide guidelines for future development purposes. Furthermore, the research identified crucial issues that should receive immediate attention from stakeholders across the industry as well as government.
- Full Text:
- Date Issued: 2016
Trophic interactions in an austral temperate ephemeral pond inferred using stable isotope analysis
- Dalu, Tatenda, Weyl, Olaf L F, Froneman, P William, Wasserman, Ryan J
- Authors: Dalu, Tatenda , Weyl, Olaf L F , Froneman, P William , Wasserman, Ryan J
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68022 , vital:29185 , https://doi.org/10.1007/s10750-015-2533-5
- Description: Publisher version , Ephemeral ponds are vulnerable aquatic habitats which are difficult to protect given their dynamic nature and sensitivity to degradation during dry periods. Little information is available on these habitats in austral regions, with almost no information on food-web structure and complexity. The study aimed to assess trophic interactions among dominant organisms in an ephemeral pond food web, and investigate the importance of autochthonous and allochthonous carbon, using 13C and 15N isotopes. Results of the investigation suggest that the food web comprised four trophic levels, with the top predators being Notonectids (Notonecta sp.) and diving beetles (Cybister tripunctatus (Olivier)). Intermediary trophic levels comprised zooplankton (daphniids and copepodids), macroinvertebrates (e.g. micronectids and molluscs) and tadpoles. Generalist feeders dominated the higher trophic levels (>3) with specialists comprising the lower trophic levels (≤3). The consumers preferred autochthonous fine particulate organic matter, epiphyton and submerged macrophyte organic matter sources over allochthonous sources. Autochthonous organic matter was transferred to the food web via zooplankton and select macroinvertebrates including Micronecta sp. and Physa sp. The food-web structure within the pond appeared to reflect the secondary stage of trophic structural complexity in the evolution of ephemeral ponds over the course of their hydro-period.
- Full Text: false
- Date Issued: 2016
- Authors: Dalu, Tatenda , Weyl, Olaf L F , Froneman, P William , Wasserman, Ryan J
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68022 , vital:29185 , https://doi.org/10.1007/s10750-015-2533-5
- Description: Publisher version , Ephemeral ponds are vulnerable aquatic habitats which are difficult to protect given their dynamic nature and sensitivity to degradation during dry periods. Little information is available on these habitats in austral regions, with almost no information on food-web structure and complexity. The study aimed to assess trophic interactions among dominant organisms in an ephemeral pond food web, and investigate the importance of autochthonous and allochthonous carbon, using 13C and 15N isotopes. Results of the investigation suggest that the food web comprised four trophic levels, with the top predators being Notonectids (Notonecta sp.) and diving beetles (Cybister tripunctatus (Olivier)). Intermediary trophic levels comprised zooplankton (daphniids and copepodids), macroinvertebrates (e.g. micronectids and molluscs) and tadpoles. Generalist feeders dominated the higher trophic levels (>3) with specialists comprising the lower trophic levels (≤3). The consumers preferred autochthonous fine particulate organic matter, epiphyton and submerged macrophyte organic matter sources over allochthonous sources. Autochthonous organic matter was transferred to the food web via zooplankton and select macroinvertebrates including Micronecta sp. and Physa sp. The food-web structure within the pond appeared to reflect the secondary stage of trophic structural complexity in the evolution of ephemeral ponds over the course of their hydro-period.
- Full Text: false
- Date Issued: 2016
Two in one: cryptic species discovered in biological control agent populations using molecular data and crossbreeding experiments
- Paterson, Iain D, Mangan, Rose, Downie, Douglas A, Coetzee, Julie A, Hill, Martin P, Burke, Ashley M, Downey, Paul O, Henry, Thomas J, Compton, Stephen G
- Authors: Paterson, Iain D , Mangan, Rose , Downie, Douglas A , Coetzee, Julie A , Hill, Martin P , Burke, Ashley M , Downey, Paul O , Henry, Thomas J , Compton, Stephen G
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424877 , vital:72191 , xlink:href="https://doi.org/10.1002/ece3.2297"
- Description: There are many examples of cryptic species that have been identified through DNA-barcoding or other genetic techniques. There are, however, very few confirmations of cryptic species being reproductively isolated. This study presents one of the few cases of cryptic species that has been confirmed to be reproductively isolated and therefore true species according to the biological species concept. The cryptic species are of special interest because they were discovered within biological control agent populations. Two geographically isolated populations of Eccritotarsus catarinensis (Carvalho) [Hemiptera: Miridae], a biological control agent for the invasive aquatic macrophyte, water hyacinth, Eichhornia crassipes (Mart.) Solms [Pontederiaceae], in South Africa, were sampled from the native range of the species in South America. Morphological characteristics indicated that both populations were the same species according to the current taxonomy, but subsequent DNA analysis and breeding experiments revealed that the two populations are reproductively isolated. Crossbreeding experiments resulted in very few hybrid offspring when individuals were forced to interbreed with individuals of the other population, and no hybrid offspring were recorded when a choice of mate from either population was offered. The data indicate that the two populations are cryptic species that are reproductively incompatible. Subtle but reliable diagnostic characteristics were then identified to distinguish between the two species which would have been considered intraspecific variation without the data from the genetics and interbreeding experiments. These findings suggest that all consignments of biological control agents from allopatric populations should be screened for cryptic species using genetic techniques and that the importation of multiple consignments of the same species for biological control should be conducted with caution.
- Full Text:
- Date Issued: 2016
- Authors: Paterson, Iain D , Mangan, Rose , Downie, Douglas A , Coetzee, Julie A , Hill, Martin P , Burke, Ashley M , Downey, Paul O , Henry, Thomas J , Compton, Stephen G
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424877 , vital:72191 , xlink:href="https://doi.org/10.1002/ece3.2297"
- Description: There are many examples of cryptic species that have been identified through DNA-barcoding or other genetic techniques. There are, however, very few confirmations of cryptic species being reproductively isolated. This study presents one of the few cases of cryptic species that has been confirmed to be reproductively isolated and therefore true species according to the biological species concept. The cryptic species are of special interest because they were discovered within biological control agent populations. Two geographically isolated populations of Eccritotarsus catarinensis (Carvalho) [Hemiptera: Miridae], a biological control agent for the invasive aquatic macrophyte, water hyacinth, Eichhornia crassipes (Mart.) Solms [Pontederiaceae], in South Africa, were sampled from the native range of the species in South America. Morphological characteristics indicated that both populations were the same species according to the current taxonomy, but subsequent DNA analysis and breeding experiments revealed that the two populations are reproductively isolated. Crossbreeding experiments resulted in very few hybrid offspring when individuals were forced to interbreed with individuals of the other population, and no hybrid offspring were recorded when a choice of mate from either population was offered. The data indicate that the two populations are cryptic species that are reproductively incompatible. Subtle but reliable diagnostic characteristics were then identified to distinguish between the two species which would have been considered intraspecific variation without the data from the genetics and interbreeding experiments. These findings suggest that all consignments of biological control agents from allopatric populations should be screened for cryptic species using genetic techniques and that the importation of multiple consignments of the same species for biological control should be conducted with caution.
- Full Text:
- Date Issued: 2016
Two uses of DNA sequence variation in tracing evolutionary processes in Old World primates (Primates: Catarrhini)
- Authors: Dosi, Banele
- Date: 2016
- Subjects: Primates -- Evolution Monkeys Cercopithecidae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8022 , vital:31464
- Description: Primate evolution is particularly interesting to humans, because it includes our own history. Molecular genetics is by far the most dynamic field in contemporary biology, and offers a host of new techniques for investigating evolutionary processes and patterns. In the mid-twentieth century molecular genetics evolved from being a means of visualising hidden variation (e.g. allozymes) to tracing phylogenetic relationships between and among species (evolutionary histories of populations), and now has a wide variety of applications in medicine, species identification and relationships, and even wildlife forensics. For my Master’s project I investigated two applications of molecular genetic analysis to questions regarding the evolution of Old World monkeys (Catarrhini). First, I participated in a study designed to test the hypothesis that different primate social structures – particularly mating systems – may be reflected in the structure of a species genome. We investigated whether increased sperm production as a result of sexual selection increases the number of copy number variations (CNVs) that can be detected by comparing the male specific region Y (MSY) located on the Y chromosome in a sample of primate species. We did not find a clear differentiation between the primate species as hypothesised, which thus requires a more complex explanation, e.g. in terms of the type of environment rather than the mating system of the species, or possibly the active/inactive status of the genes. The second part of my study was phylogeographic in approach. I collaborated with researchers studying the distribution of Afromontane samango monkeys (Cercopithecus albogularis labiatus) in the Eastern Cape. I sequenced tissues from 5 samango monkey specimens found opportunistically in the Hogsback and coastal forests and analysed their genetic variation relative to the data published by Dalton et al. 2015. The Hogsback sample was not monophyletic relative to the sample from the coastal forests, indicating that, on the basis of this very small sample size, these populations have not been separated historically. In order to validate this conclusion, I will need to investigate a larger sample size. From this study I developed valuable skills in the areas of the laboratory techniques involved in molecular sequence analysis, and an appreciation for the importance of large sample sizes in deriving reliable results. I intend to continue in the future with a phylogeographic study of samango monkeys.
- Full Text:
- Date Issued: 2016
- Authors: Dosi, Banele
- Date: 2016
- Subjects: Primates -- Evolution Monkeys Cercopithecidae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8022 , vital:31464
- Description: Primate evolution is particularly interesting to humans, because it includes our own history. Molecular genetics is by far the most dynamic field in contemporary biology, and offers a host of new techniques for investigating evolutionary processes and patterns. In the mid-twentieth century molecular genetics evolved from being a means of visualising hidden variation (e.g. allozymes) to tracing phylogenetic relationships between and among species (evolutionary histories of populations), and now has a wide variety of applications in medicine, species identification and relationships, and even wildlife forensics. For my Master’s project I investigated two applications of molecular genetic analysis to questions regarding the evolution of Old World monkeys (Catarrhini). First, I participated in a study designed to test the hypothesis that different primate social structures – particularly mating systems – may be reflected in the structure of a species genome. We investigated whether increased sperm production as a result of sexual selection increases the number of copy number variations (CNVs) that can be detected by comparing the male specific region Y (MSY) located on the Y chromosome in a sample of primate species. We did not find a clear differentiation between the primate species as hypothesised, which thus requires a more complex explanation, e.g. in terms of the type of environment rather than the mating system of the species, or possibly the active/inactive status of the genes. The second part of my study was phylogeographic in approach. I collaborated with researchers studying the distribution of Afromontane samango monkeys (Cercopithecus albogularis labiatus) in the Eastern Cape. I sequenced tissues from 5 samango monkey specimens found opportunistically in the Hogsback and coastal forests and analysed their genetic variation relative to the data published by Dalton et al. 2015. The Hogsback sample was not monophyletic relative to the sample from the coastal forests, indicating that, on the basis of this very small sample size, these populations have not been separated historically. In order to validate this conclusion, I will need to investigate a larger sample size. From this study I developed valuable skills in the areas of the laboratory techniques involved in molecular sequence analysis, and an appreciation for the importance of large sample sizes in deriving reliable results. I intend to continue in the future with a phylogeographic study of samango monkeys.
- Full Text:
- Date Issued: 2016
Ukuzotywa kwabalinganiswa ababhinqileyo abaziintloko kwiidrama zolwimi lwesiXhosa bezotywa ngababhali abasini sobuduna kwakunye nabo babhinqileyo
- Authors: Bukula, Andiswa
- Date: 2016
- Subjects: Xhosa literature -- Research Gender identity in literature , Gender nonconformity Women -- South Africa -- Drama
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/18431 , vital:28645
- Description: Eli phepha lithiywe “Ukuzotywa kwabalinganiswa ababhinqileyo, abazintloko kwidrama zolwimi lwesiXhosa, bezotywa ngababhali besini sobuduna nesini sobukhomokazi liza kube lijongene nendlela apho ababhali abasini esohlukileyo, abathi babazobe ngayo abalinganiswa abayintloko, abangamabhinqa kwizibhalo zabo zedrama zelwimi lwesiXhosa. Apha kuzobe kujongwe ingakumbi ababhali abasini sobuduna, ngenjongo yokuveza umba wokuba ababhali besini sobukhomokazi babazoba abalinganiswa ababhinqileyo nje ngabantu abangenamiqolo okuzimela ngaphandle kokuba kubekho indoda obomini babo. Aba babhali babazoba abalinganiswa ababhiqileyo phansti kwala ngcamango yokuba, apho umntu obhinqileyo ekumela afumaneke khona kusezimbizeni apho baphekela usapho lwabo rhoqo, ekucoceni umzi nasekukhuliseni abantwana, hayi enye into engaphaya koko. Ngoko ke eli phepha libhalwe ngenjongo yokuphelisa oku dodobalisa loo ngcamango. Baninzi kea bantu abaphikisana nale ndlela yaphotho lwamabhinqa ngamadoda abo, nangamanye amadoda nje jikilele, eli phepha lizobe lingqinelana nolo ninzi lwabantu abathi loo mpatho mbi yamabhinqa mayiphele, kuvezwe imeko yokuba kukho ulingano phakathi kwamabhinqa kunye nababt abasini sobukhomakazi. Int ethetha ukuba eli phepha lizakuti ligqithele lijonge kwaye liveze indlela apho kungati kuekho ulingwano phathi kwezini zimbini, nendlela apho uwonke wonke angakwazi ukuphila ngentlonipho omnye komnye kungekho zimpatho mbi, okanye sini sinesikhundla esiphakamileyo kunesinye.
- Full Text:
- Date Issued: 2016
- Authors: Bukula, Andiswa
- Date: 2016
- Subjects: Xhosa literature -- Research Gender identity in literature , Gender nonconformity Women -- South Africa -- Drama
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/18431 , vital:28645
- Description: Eli phepha lithiywe “Ukuzotywa kwabalinganiswa ababhinqileyo, abazintloko kwidrama zolwimi lwesiXhosa, bezotywa ngababhali besini sobuduna nesini sobukhomokazi liza kube lijongene nendlela apho ababhali abasini esohlukileyo, abathi babazobe ngayo abalinganiswa abayintloko, abangamabhinqa kwizibhalo zabo zedrama zelwimi lwesiXhosa. Apha kuzobe kujongwe ingakumbi ababhali abasini sobuduna, ngenjongo yokuveza umba wokuba ababhali besini sobukhomokazi babazoba abalinganiswa ababhinqileyo nje ngabantu abangenamiqolo okuzimela ngaphandle kokuba kubekho indoda obomini babo. Aba babhali babazoba abalinganiswa ababhiqileyo phansti kwala ngcamango yokuba, apho umntu obhinqileyo ekumela afumaneke khona kusezimbizeni apho baphekela usapho lwabo rhoqo, ekucoceni umzi nasekukhuliseni abantwana, hayi enye into engaphaya koko. Ngoko ke eli phepha libhalwe ngenjongo yokuphelisa oku dodobalisa loo ngcamango. Baninzi kea bantu abaphikisana nale ndlela yaphotho lwamabhinqa ngamadoda abo, nangamanye amadoda nje jikilele, eli phepha lizobe lingqinelana nolo ninzi lwabantu abathi loo mpatho mbi yamabhinqa mayiphele, kuvezwe imeko yokuba kukho ulingano phakathi kwamabhinqa kunye nababt abasini sobukhomakazi. Int ethetha ukuba eli phepha lizakuti ligqithele lijonge kwaye liveze indlela apho kungati kuekho ulingwano phathi kwezini zimbini, nendlela apho uwonke wonke angakwazi ukuphila ngentlonipho omnye komnye kungekho zimpatho mbi, okanye sini sinesikhundla esiphakamileyo kunesinye.
- Full Text:
- Date Issued: 2016
Ultra-high precision grinding of BK7 glass
- Authors: Onwuka, Goodness Raluchukwu
- Date: 2016
- Subjects: Machining , Machine-tools -- Monitoring , Acoustic emission
- Language: English
- Type: Thesis , Masters , MEngineering
- Identifier: http://hdl.handle.net/10948/5203 , vital:20820
- Description: With the increase in the application of ultra-precision manufactured parts and the absence of much participation of researchers in ultra-high precision grinding of optical glasses which has a high rate of demand in the industries, it becomes imperative to garner a full understanding of the production of these precision optics using the above-listed technology. Single point inclined axes grinding configuration and Box-Behnken experimental design was developed and applied to the ultra-high precision grinding of BK7 glass. A high sampling acoustic emission monitoring system was implemented to monitor the process. The research tends to monitor the ultra-high precision grinding of BK7 glass using acoustic emission which has proven to be an effective sensing technique to monitor grinding processes. Response surface methodology was adopted to analyze the effect of the interaction between the machining parameters: feed, speed, depth of cut and the generated surface roughness. Furthermore, back propagation Artificial Neural Network was also implemented through careful feature extraction and selection process. The proposed models are aimed at creating a database guide to the ultra-high precision grinding of precision optics.
- Full Text:
- Date Issued: 2016
- Authors: Onwuka, Goodness Raluchukwu
- Date: 2016
- Subjects: Machining , Machine-tools -- Monitoring , Acoustic emission
- Language: English
- Type: Thesis , Masters , MEngineering
- Identifier: http://hdl.handle.net/10948/5203 , vital:20820
- Description: With the increase in the application of ultra-precision manufactured parts and the absence of much participation of researchers in ultra-high precision grinding of optical glasses which has a high rate of demand in the industries, it becomes imperative to garner a full understanding of the production of these precision optics using the above-listed technology. Single point inclined axes grinding configuration and Box-Behnken experimental design was developed and applied to the ultra-high precision grinding of BK7 glass. A high sampling acoustic emission monitoring system was implemented to monitor the process. The research tends to monitor the ultra-high precision grinding of BK7 glass using acoustic emission which has proven to be an effective sensing technique to monitor grinding processes. Response surface methodology was adopted to analyze the effect of the interaction between the machining parameters: feed, speed, depth of cut and the generated surface roughness. Furthermore, back propagation Artificial Neural Network was also implemented through careful feature extraction and selection process. The proposed models are aimed at creating a database guide to the ultra-high precision grinding of precision optics.
- Full Text:
- Date Issued: 2016
Ulwaluko kwa Xhosa: young Xhosa men's lived experiences in the context of traditional male initiation
- Authors: Siswana, Anele
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3271 , http://hdl.handle.net/10962/d1020840
- Description: This thesis explores the lived experiences of young amaXhosa men in relation to U!walukokwa Xhosa (traditional male initiation [TMI]) and its impact on their sense of masculinity. The conceptual framework of this study is located within African epistemology focusing on indigenous knowledge systems (IKS) in South Africa. The study aimed at enabling young amaXhosa men who had undergone TMI to reflect on their first-hand, personal accounts of Ulwa/ukokwa Xhosa and manhood. Six semistructured interviews and a follow up focus group discussion were held with 23-27 years old amaXhosa men residing in Joza Township in Grahamstown, Eastern Cape. Participants were identified through purposive sampling. The thesis reports on the following findings: (a) the significance of the place/location of initiation, and the guise of modernity; (b) feelings of anticipation experienced by the young men; (c) the theme on ubudoda(manhood) affirmation Ndiyindoda!; (d) the theme on the concealment of pain (perseverance); (e) the theme on respect for self and others and ubuntu;(f) Uzimelegeqe (independence and autonomy) and (g) social role and responsibility. The paper argues for the relevance of TMI as a significantrite of passage from boyhood to manhood among amaXhosa men.
- Full Text:
- Date Issued: 2016
- Authors: Siswana, Anele
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3271 , http://hdl.handle.net/10962/d1020840
- Description: This thesis explores the lived experiences of young amaXhosa men in relation to U!walukokwa Xhosa (traditional male initiation [TMI]) and its impact on their sense of masculinity. The conceptual framework of this study is located within African epistemology focusing on indigenous knowledge systems (IKS) in South Africa. The study aimed at enabling young amaXhosa men who had undergone TMI to reflect on their first-hand, personal accounts of Ulwa/ukokwa Xhosa and manhood. Six semistructured interviews and a follow up focus group discussion were held with 23-27 years old amaXhosa men residing in Joza Township in Grahamstown, Eastern Cape. Participants were identified through purposive sampling. The thesis reports on the following findings: (a) the significance of the place/location of initiation, and the guise of modernity; (b) feelings of anticipation experienced by the young men; (c) the theme on ubudoda(manhood) affirmation Ndiyindoda!; (d) the theme on the concealment of pain (perseverance); (e) the theme on respect for self and others and ubuntu;(f) Uzimelegeqe (independence and autonomy) and (g) social role and responsibility. The paper argues for the relevance of TMI as a significantrite of passage from boyhood to manhood among amaXhosa men.
- Full Text:
- Date Issued: 2016
Un Langage, des Visions, une Passerelle:
- Authors: Tshilumba Mukendi, J S
- Date: 2016
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/146177 , vital:38502 , ISBN 9789074816496 , https://books.google.co.za/books?id=QDSdAQAACAAJanddq=Creer+en+postcolonie:+Voix+et+dissidences+belgo-congolaise+2010-2015andhl=enandsa=Xandved=0ahUKEwjts_Si_b_pAhXvShUIHWXwCd4Q6AEIJzAA
- Description: Book abstract. The authors and artists (Baloji, Toma Muteba Luntumbue, Nganji Laeh, Nina Miskina, Joëlle Sambi, Sarah Arens, Heleen Debeuckelaere, Bénédicte Kumbi ...) who contributed to the work to debate the Belgian postcolonial question and it will be punctuated by poetic and musical stops.
- Full Text:
- Date Issued: 2016
- Authors: Tshilumba Mukendi, J S
- Date: 2016
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/146177 , vital:38502 , ISBN 9789074816496 , https://books.google.co.za/books?id=QDSdAQAACAAJanddq=Creer+en+postcolonie:+Voix+et+dissidences+belgo-congolaise+2010-2015andhl=enandsa=Xandved=0ahUKEwjts_Si_b_pAhXvShUIHWXwCd4Q6AEIJzAA
- Description: Book abstract. The authors and artists (Baloji, Toma Muteba Luntumbue, Nganji Laeh, Nina Miskina, Joëlle Sambi, Sarah Arens, Heleen Debeuckelaere, Bénédicte Kumbi ...) who contributed to the work to debate the Belgian postcolonial question and it will be punctuated by poetic and musical stops.
- Full Text:
- Date Issued: 2016
Understanding how grade 8 Physical Science teachers make use of learners’ prior everyday knowledge when teaching static electricity: A case study
- Authors: Iyambo, Toini
- Date: 2016
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/1320 , vital:20046
- Description: Over the last decade of my teaching I have been grappling with how to incorporate learners’ prior everyday knowledge into my Physical Science lessons to enable me to close the gap between school science and everyday knowledge. I conducted this case study in two schools, one in Omusati region and one in Ohangwena Region, Namibia. Its purpose was to investigate how grade 8 Physical Science teachers make use of learners’ prior everyday knowledge when teaching the topic of static electricity. Underpinned by an interpretive paradigm, the study made use of document analysis, observation (lessons were also video-taped) and semi-structured interviews to generate the data. Three data generating techniques were used for triangulation and validation purposes. To further validate the data, transcripts of video-taped lessons and interviews were sent back to the research participants for member checking. The main findings of my study are that teachers did incorporate learners’ prior knowledge in the lesson presentation on static electricity. It emerged from the study that, learners possess a great deal of prior everyday scientific and non-scientific knowledge and experiences about static electricity that they had acquired from their communities. Also, mobilization of learners' everyday knowledge and experiences about static electricity enabled learner engagement during the science lessons. Likewise, engaging learners in demonstrations on static electricity helped them to make meaning of the scientific concepts involved in the topic. It also emerged from this study that teachers face challenges of lack of documentation of indigenous knowledge which is potentially a form of prior knowledge, language barriers and a lack of resources. Based on my research findings, I therefore, recommend that learners' prior everyday knowledge and experiences about static electricity should be incorporated during the teaching and learning process.
- Full Text:
- Date Issued: 2016
- Authors: Iyambo, Toini
- Date: 2016
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/1320 , vital:20046
- Description: Over the last decade of my teaching I have been grappling with how to incorporate learners’ prior everyday knowledge into my Physical Science lessons to enable me to close the gap between school science and everyday knowledge. I conducted this case study in two schools, one in Omusati region and one in Ohangwena Region, Namibia. Its purpose was to investigate how grade 8 Physical Science teachers make use of learners’ prior everyday knowledge when teaching the topic of static electricity. Underpinned by an interpretive paradigm, the study made use of document analysis, observation (lessons were also video-taped) and semi-structured interviews to generate the data. Three data generating techniques were used for triangulation and validation purposes. To further validate the data, transcripts of video-taped lessons and interviews were sent back to the research participants for member checking. The main findings of my study are that teachers did incorporate learners’ prior knowledge in the lesson presentation on static electricity. It emerged from the study that, learners possess a great deal of prior everyday scientific and non-scientific knowledge and experiences about static electricity that they had acquired from their communities. Also, mobilization of learners' everyday knowledge and experiences about static electricity enabled learner engagement during the science lessons. Likewise, engaging learners in demonstrations on static electricity helped them to make meaning of the scientific concepts involved in the topic. It also emerged from this study that teachers face challenges of lack of documentation of indigenous knowledge which is potentially a form of prior knowledge, language barriers and a lack of resources. Based on my research findings, I therefore, recommend that learners' prior everyday knowledge and experiences about static electricity should be incorporated during the teaching and learning process.
- Full Text:
- Date Issued: 2016