A bulk and fraction-specific geochemical study of the origin of diverse high-grade hematitic iron ores from the Transvaal Supergroup, Northern Cape Province, South Africa
- Authors: Moloto, William
- Date: 2017
- Subjects: Iron ore -- South Africa -- Transvaal Supergroup , Hematite -- South Africa -- Transvaal Supergroup , Transvaal Supergroup (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/50546 , vital:25998
- Description: The Paleoproterozoic Transvaal Supergroup in the Northern Cape Province of South Africa is host to high-grade, Banded Iron Formation-hosted hematite iron-ore deposits and is the country’s most important source of iron to date. Previous studies suggest the origin of these iron ores to be ancient supergene, and that the ore forming process would have therefore pre-dated deposition of the basal Mapedi shales of the Olifansthoek Supergroup that unconformably overlies the Transvaal strata. The nature of the protolith to the ores has been suggested to be largely BIF of the Asbestos Hills Subgroup, and mainly the Kuruman BIF. The work presented in this thesis seeks to provide insights into the diversity of processes that are likely to have been involved during the genesis of these high-grade iron ores, in the context of constraining the pre-ore lithologies and the relative role of supergene-style, largely residual enrichment processes versus any possible metasomatic hydrothermal effects. This study had as primary focus the application of combined bulk and fraction-specific geochemical applications on representative iron-ore samples from four different localities in the Northern Cape Province, namely King/Khumani, Beeshoek, Heuninkranz and Hotazel. The collected samples show a variety of textures and also capture different pre-unconformity stratigraphic sections of BIF. The key objective was to assess whether the fraction-specific analytical results could provide any firm constraints for the origin of the ferrous and non-ferrous matrix fractions of the ores, namely whether they represent any combinations of protolith residue, allochtonously-introduced detritus or hydrothermally-derived material, and whether the results are comparable and consistent across all samples studied. In particular, constraints were sought as to whether the ore protolith was exclusively BIF or may potentially have contained at least a fraction of other lithologic types, such as shale; and whether there is sufficient evidence to support solely a supergene model for the ores or the data suggest other more epigenetic models of ore formation involving the action of hydrothermal fluids Bulk-rock geochemical analyses reveal the overwhelming dominance of Fe-oxide (as hematite) in all samples, at concentrations as high as 99 wt.% Fe2O3. Major and trace-element abundances of all samples were re-calculated assuming only iron addition from the postulated protolith (average BIF and shale), and the results revealed atypical enrichments in the iron ores by comparison to average BIF, and more shale-like relative abundances when normalised against the Post-Archaean Average Shale (PAAS). Specifically, BIF-normalised diagrams show relative enrichments by as much as 53-95% for Al2O3; 11-86% for TiO2; and 4-60% for P2O5. By contrast, PAAS-normalised values display enrichments of 1-3% for Al2O3, 0.2-3% for TiO2, and 3-13% for P2O5. Similar observations can be made for the greatest majority of trace elements when normalised against average BIF as compared to normalisation against PAAS. A suite of trace element that include alkali earths (e.g. Ba, Sr) and transition metals (e.g. Ni, Zn) show enrichments that are unrelated to the apparently detrital siliciclastic fraction of the ores, and are therefore linked to a possible hydrothermal input. Fraction-specific extractions were performed via the adaptation of existing dissolution protocols using oxalic acid (iron-oxide fraction) followed by HF digestion (silicate-fraction). The analyses of the produced aliquots using ICP-MS techniques, focused mainly on the REE abundances of the separated ferrous and non-ferrous matrix fractions and their comparisons to bulk-rock REE signatures. The results lend further support to the suggestion that the ore samples contain a predominant shale-like signal which does not directly compare to published REE signatures for supergene or hydrothermal BIF-hosted iron-ore deposits alike. The data therefore collectively point to a post-unconformity epigenetic hydrothermal event/s of iron ore-formation that would have exploited not only BIF but also shale as suitable pre-ore protolith.
- Full Text:
- Date Issued: 2017
- Authors: Moloto, William
- Date: 2017
- Subjects: Iron ore -- South Africa -- Transvaal Supergroup , Hematite -- South Africa -- Transvaal Supergroup , Transvaal Supergroup (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/50546 , vital:25998
- Description: The Paleoproterozoic Transvaal Supergroup in the Northern Cape Province of South Africa is host to high-grade, Banded Iron Formation-hosted hematite iron-ore deposits and is the country’s most important source of iron to date. Previous studies suggest the origin of these iron ores to be ancient supergene, and that the ore forming process would have therefore pre-dated deposition of the basal Mapedi shales of the Olifansthoek Supergroup that unconformably overlies the Transvaal strata. The nature of the protolith to the ores has been suggested to be largely BIF of the Asbestos Hills Subgroup, and mainly the Kuruman BIF. The work presented in this thesis seeks to provide insights into the diversity of processes that are likely to have been involved during the genesis of these high-grade iron ores, in the context of constraining the pre-ore lithologies and the relative role of supergene-style, largely residual enrichment processes versus any possible metasomatic hydrothermal effects. This study had as primary focus the application of combined bulk and fraction-specific geochemical applications on representative iron-ore samples from four different localities in the Northern Cape Province, namely King/Khumani, Beeshoek, Heuninkranz and Hotazel. The collected samples show a variety of textures and also capture different pre-unconformity stratigraphic sections of BIF. The key objective was to assess whether the fraction-specific analytical results could provide any firm constraints for the origin of the ferrous and non-ferrous matrix fractions of the ores, namely whether they represent any combinations of protolith residue, allochtonously-introduced detritus or hydrothermally-derived material, and whether the results are comparable and consistent across all samples studied. In particular, constraints were sought as to whether the ore protolith was exclusively BIF or may potentially have contained at least a fraction of other lithologic types, such as shale; and whether there is sufficient evidence to support solely a supergene model for the ores or the data suggest other more epigenetic models of ore formation involving the action of hydrothermal fluids Bulk-rock geochemical analyses reveal the overwhelming dominance of Fe-oxide (as hematite) in all samples, at concentrations as high as 99 wt.% Fe2O3. Major and trace-element abundances of all samples were re-calculated assuming only iron addition from the postulated protolith (average BIF and shale), and the results revealed atypical enrichments in the iron ores by comparison to average BIF, and more shale-like relative abundances when normalised against the Post-Archaean Average Shale (PAAS). Specifically, BIF-normalised diagrams show relative enrichments by as much as 53-95% for Al2O3; 11-86% for TiO2; and 4-60% for P2O5. By contrast, PAAS-normalised values display enrichments of 1-3% for Al2O3, 0.2-3% for TiO2, and 3-13% for P2O5. Similar observations can be made for the greatest majority of trace elements when normalised against average BIF as compared to normalisation against PAAS. A suite of trace element that include alkali earths (e.g. Ba, Sr) and transition metals (e.g. Ni, Zn) show enrichments that are unrelated to the apparently detrital siliciclastic fraction of the ores, and are therefore linked to a possible hydrothermal input. Fraction-specific extractions were performed via the adaptation of existing dissolution protocols using oxalic acid (iron-oxide fraction) followed by HF digestion (silicate-fraction). The analyses of the produced aliquots using ICP-MS techniques, focused mainly on the REE abundances of the separated ferrous and non-ferrous matrix fractions and their comparisons to bulk-rock REE signatures. The results lend further support to the suggestion that the ore samples contain a predominant shale-like signal which does not directly compare to published REE signatures for supergene or hydrothermal BIF-hosted iron-ore deposits alike. The data therefore collectively point to a post-unconformity epigenetic hydrothermal event/s of iron ore-formation that would have exploited not only BIF but also shale as suitable pre-ore protolith.
- Full Text:
- Date Issued: 2017
Performance of project management units (PMUS): the case of Sarah Baartman District Municipality
- Authors: Monare, Thabang
- Date: 2017
- Subjects: Project management -- South Africa -- Eastern Cape -- Evaluation , Construction industry -- South Africa -- Eastern Cape -- Management Construction industry -- South Africa -- Eastern Cape -- Quality control
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/19081 , vital:28771
- Description: The Municipal Infrastructure Grant programme (MIG) is South Africa’s largest local government infrastructure development funding. Designed to improve service delivery through financing the cost of eradicating basic services backlogs created by Apartheid’s legacy of ‘separate development’, MIG is also intended to be part of government’s overall strategy to eliminate the ‘triple challenge’ of poverty, unemployment and growing inequality. Through government’s active policy which sought to transform and enhance the municipal infrastructure service delivery capacity, effective project management was identified as an integral function of municipalities with a developmental role in terms of the Constitutional mandate. This led to the establishment of Project Management Units (PMUs) tasked with administering the MIG funds and managing the infrastructure projects effectively. Whilst MIG’s overall key principles were clearly defined in the MIG policy framework, the attainment of project success has proved elusive for most municipalities and this manifestation has only been partially examined. The purpose of this study is to explore factors affecting project success with the establishment of PMUs in Sarah Baartman District Municipality (SBDM) in the Eastern Cape Province in South Africa, with the aim of contributing to the refinement of best-practice for project implementation. A multiple case study approach was preferred, preceded by an extensive review of relevant literature on the basic tenets of project success. This exercise culminated in the refinement of research questions which were then posed in interviews to a purposive sample of PMU managers within SBDM. The findings from the study revealed the centrality of the dominant features required to influence the probability of positive outcomes such as institutional capacity, organisational culture and infrastructure governance. The research concludes by proposing ways of improving on these three components in the delivery of municipal infrastructure.
- Full Text:
- Date Issued: 2017
- Authors: Monare, Thabang
- Date: 2017
- Subjects: Project management -- South Africa -- Eastern Cape -- Evaluation , Construction industry -- South Africa -- Eastern Cape -- Management Construction industry -- South Africa -- Eastern Cape -- Quality control
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/19081 , vital:28771
- Description: The Municipal Infrastructure Grant programme (MIG) is South Africa’s largest local government infrastructure development funding. Designed to improve service delivery through financing the cost of eradicating basic services backlogs created by Apartheid’s legacy of ‘separate development’, MIG is also intended to be part of government’s overall strategy to eliminate the ‘triple challenge’ of poverty, unemployment and growing inequality. Through government’s active policy which sought to transform and enhance the municipal infrastructure service delivery capacity, effective project management was identified as an integral function of municipalities with a developmental role in terms of the Constitutional mandate. This led to the establishment of Project Management Units (PMUs) tasked with administering the MIG funds and managing the infrastructure projects effectively. Whilst MIG’s overall key principles were clearly defined in the MIG policy framework, the attainment of project success has proved elusive for most municipalities and this manifestation has only been partially examined. The purpose of this study is to explore factors affecting project success with the establishment of PMUs in Sarah Baartman District Municipality (SBDM) in the Eastern Cape Province in South Africa, with the aim of contributing to the refinement of best-practice for project implementation. A multiple case study approach was preferred, preceded by an extensive review of relevant literature on the basic tenets of project success. This exercise culminated in the refinement of research questions which were then posed in interviews to a purposive sample of PMU managers within SBDM. The findings from the study revealed the centrality of the dominant features required to influence the probability of positive outcomes such as institutional capacity, organisational culture and infrastructure governance. The research concludes by proposing ways of improving on these three components in the delivery of municipal infrastructure.
- Full Text:
- Date Issued: 2017
A case-control approach to assess variability in distribution of distance between transcription factor binding site and transcription start site
- Authors: Moos, Abdul Ragmaan
- Date: 2017
- Subjects: Transcription factors , Proteomics , Chromatin , Chromatin immunoprecipitation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/5315 , vital:20808
- Description: Using the in-silico approach, with ENCODE ChIP-seq data for various transcription factors and different cell types; we systematically compared the distance between the transcription factor binding site (TFBS) and the transcription start (TSS). Our aim was to determine if the same transcription factor binds at a different position relative to the TSS in a normal and an abnormal cell type. We compare distribution of distance of binding sites from the TSS; to make description less verbose we call this “distance” where there is no possibility of confusion. We used a case-control methodology where the distance between the TFBS and the TSS in the normal, non-cancerous or untreated cell type is the control. The distance between the TFBS and the TSS in the cancerous or treated cell type is the case. We use the distance between the TFBS and the TSS in the control as the standard. We compared the distance between the TFBS and the TSS in the case and the control. If the distance between the TFBS and the TSS in the control was greater than the distance between the TFBS and the TSS in the case, we can infer the following. The transcription factor in the case binds closer to the TSS compared to the control. If the distance between the TFBS and the TSS in the control is smaller than the distance between the TFBS and the TSS in the case, we can infer the following. The TF in the case binds further away from the TSS compared to the control. Our method is a screening method whereby we compare ChIP-seq data to determine if there is a difference in the distribution distance between the TFBS and the TSS for normal and abnormal cell types. We used the R package ChIP-Enrich to compare the distribution of distance between ChIP-seq peak and the nearest TSS. ChIP-Enrich produces a histogram with the number of ChIP-seq peaks at a certain distance from the TSS. The results indicate for some transcription factors like GM12878-cMyc and K562-cMyc there is a difference between the distribution of distance between the TFBS and the nearest TSS. cMyc has more binding sites within a distance of 1kb from the TSS in GM12878 when compared to K562. GM12878-CTCF and K562-CTCF have slight differences when comparing their distribution of distance from the TSS. This means CTCF binds almost the same distance from the TSS in both GM12878 and K562. A549-gr treated with dexamethasone is interesting because with increase dose of dexamethasone the distribution of distance from the TSS changes as well.
- Full Text:
- Date Issued: 2017
- Authors: Moos, Abdul Ragmaan
- Date: 2017
- Subjects: Transcription factors , Proteomics , Chromatin , Chromatin immunoprecipitation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/5315 , vital:20808
- Description: Using the in-silico approach, with ENCODE ChIP-seq data for various transcription factors and different cell types; we systematically compared the distance between the transcription factor binding site (TFBS) and the transcription start (TSS). Our aim was to determine if the same transcription factor binds at a different position relative to the TSS in a normal and an abnormal cell type. We compare distribution of distance of binding sites from the TSS; to make description less verbose we call this “distance” where there is no possibility of confusion. We used a case-control methodology where the distance between the TFBS and the TSS in the normal, non-cancerous or untreated cell type is the control. The distance between the TFBS and the TSS in the cancerous or treated cell type is the case. We use the distance between the TFBS and the TSS in the control as the standard. We compared the distance between the TFBS and the TSS in the case and the control. If the distance between the TFBS and the TSS in the control was greater than the distance between the TFBS and the TSS in the case, we can infer the following. The transcription factor in the case binds closer to the TSS compared to the control. If the distance between the TFBS and the TSS in the control is smaller than the distance between the TFBS and the TSS in the case, we can infer the following. The TF in the case binds further away from the TSS compared to the control. Our method is a screening method whereby we compare ChIP-seq data to determine if there is a difference in the distribution distance between the TFBS and the TSS for normal and abnormal cell types. We used the R package ChIP-Enrich to compare the distribution of distance between ChIP-seq peak and the nearest TSS. ChIP-Enrich produces a histogram with the number of ChIP-seq peaks at a certain distance from the TSS. The results indicate for some transcription factors like GM12878-cMyc and K562-cMyc there is a difference between the distribution of distance between the TFBS and the nearest TSS. cMyc has more binding sites within a distance of 1kb from the TSS in GM12878 when compared to K562. GM12878-CTCF and K562-CTCF have slight differences when comparing their distribution of distance from the TSS. This means CTCF binds almost the same distance from the TSS in both GM12878 and K562. A549-gr treated with dexamethasone is interesting because with increase dose of dexamethasone the distribution of distance from the TSS changes as well.
- Full Text:
- Date Issued: 2017
Investigating adaptation strategies to climate change by smallholder farmers : evidence from, Lesotho
- Authors: Morahanye, Mokhantso Lilian
- Date: 2017
- Subjects: Climatic changes -- South Africa Farms, Small -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5807 , vital:29397
- Description: In Lesotho, agriculture is the dominant activity and involves crop and livestock production, range management and forestry activities. The current climatic variability in the country has caused decline in food production as result of increased dry spells, frequency of droughts and erratic rainfall. These climatic events are expected to have a significant impact on the livelihoods of the smallholder farmers. In combatting the harmful effects of climate change, smallholder farmers in Lesotho have employed various adaptation strategies based on their local knowledge and limited means. While these strategies may not be optimal they obviously constitute the basis for potentially effective improved technologies which can be developed and communicated through an efficient extension system, hence the need to precisely identify them and understand the factors that affect their choice. The main objective of this study was therefore, to identify the adaptation strategies and investigate the factors influencing smallholder farmers’ choice of those adaptation strategies. The study made use of multi-stage stratified sampling technique to select 160 respondents across four agro-ecological zones (lowlands, highlands, foothills and Senqu River Valley) in Leribe and Mohales’Hoek districts of Lesotho. Primary data for the study were collected using semi - structured questionnaire assisted with interview schedules administered on the respondents. Data collected were analysed using descriptive statistics and the multinomial logistics regression model. The results show that there are more males than females, majority of the respondents’ attained primary education, and older people dominate the smallholder farming system. The adaptation strategies used in MNL model were soil and water management, crop management and livestock management. The results further revealed that soil and water management strategies were the most adopted climate change strategies amongst smallholder farmers. It is understood that marital status, age and gender, income, land tenure, crop grown, extension services, and agro-ecological zones are the determinant factors influencing the choice of the adaptation strategies. This study concludes by recommending that smallholder farmers should be sensitised about climate change and both government and non-government organisations working on climate change related issues should direct their attention to rural communities to ensure effective response to climate change.
- Full Text:
- Date Issued: 2017
- Authors: Morahanye, Mokhantso Lilian
- Date: 2017
- Subjects: Climatic changes -- South Africa Farms, Small -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5807 , vital:29397
- Description: In Lesotho, agriculture is the dominant activity and involves crop and livestock production, range management and forestry activities. The current climatic variability in the country has caused decline in food production as result of increased dry spells, frequency of droughts and erratic rainfall. These climatic events are expected to have a significant impact on the livelihoods of the smallholder farmers. In combatting the harmful effects of climate change, smallholder farmers in Lesotho have employed various adaptation strategies based on their local knowledge and limited means. While these strategies may not be optimal they obviously constitute the basis for potentially effective improved technologies which can be developed and communicated through an efficient extension system, hence the need to precisely identify them and understand the factors that affect their choice. The main objective of this study was therefore, to identify the adaptation strategies and investigate the factors influencing smallholder farmers’ choice of those adaptation strategies. The study made use of multi-stage stratified sampling technique to select 160 respondents across four agro-ecological zones (lowlands, highlands, foothills and Senqu River Valley) in Leribe and Mohales’Hoek districts of Lesotho. Primary data for the study were collected using semi - structured questionnaire assisted with interview schedules administered on the respondents. Data collected were analysed using descriptive statistics and the multinomial logistics regression model. The results show that there are more males than females, majority of the respondents’ attained primary education, and older people dominate the smallholder farming system. The adaptation strategies used in MNL model were soil and water management, crop management and livestock management. The results further revealed that soil and water management strategies were the most adopted climate change strategies amongst smallholder farmers. It is understood that marital status, age and gender, income, land tenure, crop grown, extension services, and agro-ecological zones are the determinant factors influencing the choice of the adaptation strategies. This study concludes by recommending that smallholder farmers should be sensitised about climate change and both government and non-government organisations working on climate change related issues should direct their attention to rural communities to ensure effective response to climate change.
- Full Text:
- Date Issued: 2017
Synthesis of L-menthyl glyoxylate, an important intermediate in the manufacture of ARVS, using flow chemistry technology
- Authors: Moyo, McQuillan
- Date: 2017
- Subjects: Chemistry , Pharmaceutical chemistry , Organic compounds -- Synthesis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/12019 , vital:27018
- Description: Herein an alternative approach to the conventional batch synthesis of L-menthyl glyoxylate hydrate (MGH), an important intermediate in the synthesis of drugs of importance is reported, through flow chemistry technology. MGH was initially synthesized in batch and various reaction parameters optimized. It was found to proceed to completion after 6 hours of esterifying glyoxylic acid with excess alcohol (L-menthol) in the presence of a catalyst, ideally amberlyst-15 (an ion exchange resin) at 105 °C giving a yield of 72 %. The batch reaction conditions were adopted in a continuous flow synthesis setup, using the Labtrix Start system, in which reaction conditions were optimized. The optimization of glyoxylic acid conversion (92 %) in the Labtrix Start system gave reaction conditions that resulted in low MGH selectivity (25 %) whereas the optimization for MGH selectivity (100 %) gave a conversion a poor glyoxylic acid conversion (15 %). The FlowSyn system fitted with a column reactor gave the best results, in which the optimum conditions were an excess of L-menthol (1.5 M, 6.0 equiv.), temperature (80 °C) and a residence time of 2.5 minutes with a high selectivity (77 %) and average conversion (50 %). The optimized reaction conditions for conversion and selectivity on the different flow systems did not vary significantly and similar trends were observed for the systems. It was shown that an increase in temperature, mole equivalents and residence time led to an increase in MGH conversion in all flow systems. The scale up of the esterification reaction from the Labtrix Start system (19 μL microreactor) to the FlowSyn system fitted with a 2 mL reactor chip, showed that the reaction proceeds with a slight drop in selectivity from 100 % to 92 % while conversion dropped from 15 to 12 %. On the contrary, a significant drop in conversion and selectivity were observed when the FlowSyn column reactor was up-scaled to the Elite-tubular furnace, owing to the poor mixing in the larger channel size reactor.
- Full Text:
- Date Issued: 2017
- Authors: Moyo, McQuillan
- Date: 2017
- Subjects: Chemistry , Pharmaceutical chemistry , Organic compounds -- Synthesis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/12019 , vital:27018
- Description: Herein an alternative approach to the conventional batch synthesis of L-menthyl glyoxylate hydrate (MGH), an important intermediate in the synthesis of drugs of importance is reported, through flow chemistry technology. MGH was initially synthesized in batch and various reaction parameters optimized. It was found to proceed to completion after 6 hours of esterifying glyoxylic acid with excess alcohol (L-menthol) in the presence of a catalyst, ideally amberlyst-15 (an ion exchange resin) at 105 °C giving a yield of 72 %. The batch reaction conditions were adopted in a continuous flow synthesis setup, using the Labtrix Start system, in which reaction conditions were optimized. The optimization of glyoxylic acid conversion (92 %) in the Labtrix Start system gave reaction conditions that resulted in low MGH selectivity (25 %) whereas the optimization for MGH selectivity (100 %) gave a conversion a poor glyoxylic acid conversion (15 %). The FlowSyn system fitted with a column reactor gave the best results, in which the optimum conditions were an excess of L-menthol (1.5 M, 6.0 equiv.), temperature (80 °C) and a residence time of 2.5 minutes with a high selectivity (77 %) and average conversion (50 %). The optimized reaction conditions for conversion and selectivity on the different flow systems did not vary significantly and similar trends were observed for the systems. It was shown that an increase in temperature, mole equivalents and residence time led to an increase in MGH conversion in all flow systems. The scale up of the esterification reaction from the Labtrix Start system (19 μL microreactor) to the FlowSyn system fitted with a 2 mL reactor chip, showed that the reaction proceeds with a slight drop in selectivity from 100 % to 92 % while conversion dropped from 15 to 12 %. On the contrary, a significant drop in conversion and selectivity were observed when the FlowSyn column reactor was up-scaled to the Elite-tubular furnace, owing to the poor mixing in the larger channel size reactor.
- Full Text:
- Date Issued: 2017
The effect of phosphorus fertilizer application on growth, biomass and nutritive value of Pigeon pea (Cajanus cajan (L.) Millsp.) varieties in Alice, South Africa
- Authors: Mpabanga, Nkosi
- Date: 2017
- Subjects: Phosphatic fertilizers Soil fertility Plants -- Effect of phosphorus on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6180 , vital:29501
- Description: Low soil fertility has been identified to be among the major causes of low pasture quantity and quality. Scarcity of high quality forage mainly during the dry season threatens animal productivity in some areas of South Africa, thus the need for identifying livestock feed alternatives. Pigeon pea is a woody legume that has continually been an important shrub in agroforestry and can provide protein-rich livestock feed during times of shortage. Soil fertility to support the production of pigeon pea can be enhanced by application of fertilisers. Therefore, this study was carried out firstly, to determine the effect of phosphorus fertiliser on the growth performance and biomass production of three pigeon pea varieties, and secondly, to investigate the influence of phosphorus application on the nutrient and anti-nutrient content of three pigeon pea varieties. The field experiment was done at the University of Fort Hare research farm in Alice, South Africa. The factors investigated were three pigeon pea varieties namely Chitedze 1, Chitedze 2 and CIMMYT 1 and three phosphorus fertiliser application rates of 0, 40 and 60 kg P/ha. The study was a 3× 3 factorial experiment set up in a randomised complete block design and was replicated three times. The growth performance attributes evaluated in this study include the number of branches, plant height and root collar diameter. Root collar diameter was not significantly (p>0.05) different among the pigeon pea varieties and phosphorus levels. Likewise, the application of phosphorus was not significant (p>0.05) on plant height and the number of branches of all the varieties. However, when P level was varied, there were significant differences among the varieties, and so were the interaction (p<0.05) between variety and phosphorus on plant height and the number of branches. There was no significant (p>0.05) difference among the phosphorus levels on the fresh leaf yield of Chitedze 1 and Chitedze 2, but phosphorus application at 40 kg P/ha increased the fresh leaf yield of CIMMYT 1. Phosphorus application at 60 kg P/ha increased (p<0.05) the dry matter content of Chitedze 1 and Chitedze 2. Furthermore, the results of the trial show that the application of 40 kg P/ha and 60 kg P/ha increased (p<0.05) the dry matter yield of the varieties CIMMYT 1 and Chitedze 2, respectively. The effects of phosphorus application on the nutrient composition of the three pigeon pea varieties varied. The composition of hemicellulose of all the varieties was significantly (p<0.05) increased by the application of 40 kg P/ha. Conversely, the concentration of crude protein, phosphorus, copper and iron, and the calcium to phosphorus ratio of all the pigeon pea varieties was not significantly (p>0.05) affected by phosphorus application and there was no interactive effect of variety and phosphorus. The proximate compositions of fat, total non-structural carbohydrates, ash, neutral detergent fibre, acid detergent fibre, cellulose, neutral detergent insoluble nitrogen, acid detergent insoluble nitrogen of the pigeon pea varieties varied significantly (p<0.05) at different phosphorus application levels. There was an interactive (p<0.05) effect of variety and the level of phosphorus on the concentration of calcium (Ca), potassium (K), magnesium (Mg), sodium, zinc, manganese, and the K/(Ca+Mg) ratio. The digestible dry matter, dry matter intake and the relative feed value were significantly (p<0.05) different among the pigeon pea varieties at varying phosphorus levels. The anti-nutrient composition of Chitedze 2 was not significantly (p>0.05) affected by phosphorus application but the concentration of phenols and saponins of Chitedze 1 was significantly (p<0.05) increased when 60 kg P/ha was applied, but these anti-nutrients were reduced (p<0.05) for CIMMYT 1 at 60 kg P/ha. It can be concluded that phosphorus application influences the biomass production and chemical composition while the optimum phosphorus level vary among the pigeon pea varieties.
- Full Text:
- Date Issued: 2017
- Authors: Mpabanga, Nkosi
- Date: 2017
- Subjects: Phosphatic fertilizers Soil fertility Plants -- Effect of phosphorus on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6180 , vital:29501
- Description: Low soil fertility has been identified to be among the major causes of low pasture quantity and quality. Scarcity of high quality forage mainly during the dry season threatens animal productivity in some areas of South Africa, thus the need for identifying livestock feed alternatives. Pigeon pea is a woody legume that has continually been an important shrub in agroforestry and can provide protein-rich livestock feed during times of shortage. Soil fertility to support the production of pigeon pea can be enhanced by application of fertilisers. Therefore, this study was carried out firstly, to determine the effect of phosphorus fertiliser on the growth performance and biomass production of three pigeon pea varieties, and secondly, to investigate the influence of phosphorus application on the nutrient and anti-nutrient content of three pigeon pea varieties. The field experiment was done at the University of Fort Hare research farm in Alice, South Africa. The factors investigated were three pigeon pea varieties namely Chitedze 1, Chitedze 2 and CIMMYT 1 and three phosphorus fertiliser application rates of 0, 40 and 60 kg P/ha. The study was a 3× 3 factorial experiment set up in a randomised complete block design and was replicated three times. The growth performance attributes evaluated in this study include the number of branches, plant height and root collar diameter. Root collar diameter was not significantly (p>0.05) different among the pigeon pea varieties and phosphorus levels. Likewise, the application of phosphorus was not significant (p>0.05) on plant height and the number of branches of all the varieties. However, when P level was varied, there were significant differences among the varieties, and so were the interaction (p<0.05) between variety and phosphorus on plant height and the number of branches. There was no significant (p>0.05) difference among the phosphorus levels on the fresh leaf yield of Chitedze 1 and Chitedze 2, but phosphorus application at 40 kg P/ha increased the fresh leaf yield of CIMMYT 1. Phosphorus application at 60 kg P/ha increased (p<0.05) the dry matter content of Chitedze 1 and Chitedze 2. Furthermore, the results of the trial show that the application of 40 kg P/ha and 60 kg P/ha increased (p<0.05) the dry matter yield of the varieties CIMMYT 1 and Chitedze 2, respectively. The effects of phosphorus application on the nutrient composition of the three pigeon pea varieties varied. The composition of hemicellulose of all the varieties was significantly (p<0.05) increased by the application of 40 kg P/ha. Conversely, the concentration of crude protein, phosphorus, copper and iron, and the calcium to phosphorus ratio of all the pigeon pea varieties was not significantly (p>0.05) affected by phosphorus application and there was no interactive effect of variety and phosphorus. The proximate compositions of fat, total non-structural carbohydrates, ash, neutral detergent fibre, acid detergent fibre, cellulose, neutral detergent insoluble nitrogen, acid detergent insoluble nitrogen of the pigeon pea varieties varied significantly (p<0.05) at different phosphorus application levels. There was an interactive (p<0.05) effect of variety and the level of phosphorus on the concentration of calcium (Ca), potassium (K), magnesium (Mg), sodium, zinc, manganese, and the K/(Ca+Mg) ratio. The digestible dry matter, dry matter intake and the relative feed value were significantly (p<0.05) different among the pigeon pea varieties at varying phosphorus levels. The anti-nutrient composition of Chitedze 2 was not significantly (p>0.05) affected by phosphorus application but the concentration of phenols and saponins of Chitedze 1 was significantly (p<0.05) increased when 60 kg P/ha was applied, but these anti-nutrients were reduced (p<0.05) for CIMMYT 1 at 60 kg P/ha. It can be concluded that phosphorus application influences the biomass production and chemical composition while the optimum phosphorus level vary among the pigeon pea varieties.
- Full Text:
- Date Issued: 2017
Assessment of the Department of Rural Development and Agrarian Reform's maize cropping programme in the Eastern Cape
- Authors: Mqamelo, Luvolwethu
- Date: 2017
- Subjects: Cropping systems Crops and climate Crop yields
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9165 , vital:34288
- Description: The Department of Rural Development and Agrarian Reform maize cropping programme is one of the flagship projects that has been entrusted by the provincial government to tackle the social ills faced by the rural communities of the Eastern Cape Province. The programme is in line with a number of policies that strive to unlock the agricultural potential in inducing the much talked about radical economic transformation. This study was aimed at establishing if the outlay of the implementation processes and the outcomes of the maize cropping programme in Eastern Cape are sufficient to achieve the stated objectives. The study adopted a triangulation method to get comprehensive understanding of the programme and for accuracy and verification of the data collected. A pre-tested semistructured questionnaire was used to collect the demographics and socio-economic status of the respondents; technical skills and capabilities; implementation processes of the programme and the perceptions of the participants and key strategic role players in the maize cropping programme. A total of 120 respondents from DRDAR’s 2016/2017 financial year supported list and 9 key informants were sampled for the study. Furthermore, a gross margin analysis was used to establish the viability and the sustainability of the programme with and without DRDAR’s subsidies. For purposes of determining if there was any relation between the maize enterprise income and 13 independent variables, a multiple regression model was employed. The results of the study show that the programme is dominated by old and uneducated individuals with an average age of 60 years. The implementation processes are proving to be fairly progressed however, at a very limited scale. This includes provision of production inputs and mechanization services on time, formation of self-serving legal entities and unlocking the private sector investment. The gross margins generated from the programme have been observed to be non-viable and unsustainable. As a result, only 31% of the respondents were able to attain a gross margin equal or greater than the allocable costs of producing maize both under irrigation and dry land. The results of the regression model indicated that, only 5 of the 13 independent variables (household gender, marital status, years of participation, area planted and yield) were found to have a significant effect to the maize enterprise income. Overall, the DRDAR’s maize cropping programme has failed to meet its intended objectives. In addition, more than 70 percent of the programme participants produced for subsistence purposes and showed no desire to fully commercialise their operations.
- Full Text:
- Date Issued: 2017
- Authors: Mqamelo, Luvolwethu
- Date: 2017
- Subjects: Cropping systems Crops and climate Crop yields
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9165 , vital:34288
- Description: The Department of Rural Development and Agrarian Reform maize cropping programme is one of the flagship projects that has been entrusted by the provincial government to tackle the social ills faced by the rural communities of the Eastern Cape Province. The programme is in line with a number of policies that strive to unlock the agricultural potential in inducing the much talked about radical economic transformation. This study was aimed at establishing if the outlay of the implementation processes and the outcomes of the maize cropping programme in Eastern Cape are sufficient to achieve the stated objectives. The study adopted a triangulation method to get comprehensive understanding of the programme and for accuracy and verification of the data collected. A pre-tested semistructured questionnaire was used to collect the demographics and socio-economic status of the respondents; technical skills and capabilities; implementation processes of the programme and the perceptions of the participants and key strategic role players in the maize cropping programme. A total of 120 respondents from DRDAR’s 2016/2017 financial year supported list and 9 key informants were sampled for the study. Furthermore, a gross margin analysis was used to establish the viability and the sustainability of the programme with and without DRDAR’s subsidies. For purposes of determining if there was any relation between the maize enterprise income and 13 independent variables, a multiple regression model was employed. The results of the study show that the programme is dominated by old and uneducated individuals with an average age of 60 years. The implementation processes are proving to be fairly progressed however, at a very limited scale. This includes provision of production inputs and mechanization services on time, formation of self-serving legal entities and unlocking the private sector investment. The gross margins generated from the programme have been observed to be non-viable and unsustainable. As a result, only 31% of the respondents were able to attain a gross margin equal or greater than the allocable costs of producing maize both under irrigation and dry land. The results of the regression model indicated that, only 5 of the 13 independent variables (household gender, marital status, years of participation, area planted and yield) were found to have a significant effect to the maize enterprise income. Overall, the DRDAR’s maize cropping programme has failed to meet its intended objectives. In addition, more than 70 percent of the programme participants produced for subsistence purposes and showed no desire to fully commercialise their operations.
- Full Text:
- Date Issued: 2017
Performance of a residential swimming pool air source heat pump water heater installed in Fort Beaufort, South Africa
- Authors: Mqayi, Singatha
- Date: 2017
- Subjects: Water heaters Heat pumps Swimming pools -- Heating and ventilation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4835 , vital:28532
- Description: Globally, there is growing concern about energy consumption and its diverse effects on the environment. In South Africa, the current status quo is unfavourable in the domain of energy, hence the Department of Energy, Eskom and NERSA have embarked on supporting energy efficiency technologies nationwide as a strategic goal in reducing demand on the national grid. Due to the non conservative consumption of electricity from the grid and the insufficient supply to meet its demand, the importation of crude oil is very certain. In addition, the current and most popular technology for pool water heating in the said country is the resistive element which is inefficient and non-cost-effective. The energy consumption of residential swimming pool water heating is very massive, and tariff structure shows a constant rise. Furthermore, there's a current electricity crisis during the Eskom evening peak. Hence, a reliable, efficient, cost-effective and renewable energy technology such as an air source heat pump is required as a retrofit to the existing resistive element. Furthermore, mathematical modelling is a tool that can be used to mimic the dynamic behaviour of a physical or process system. It is a computational language or mathematical equation used to predict the dynamic behaviour of physical systems [Tangwe et al., 2015]. Various methods such as numerical methods have been considered as the particular types of mathematical modelling which have been employed to predict the performance of swimming pool ASHP water heater. However, they were unreliable and expensive. Consequently, this research focused on the experimental determination of the viability and development of a mathematical model to predict the performance of swimming pool ASHP water heater. The benefit of the development and building of this model was attributed to its low cost and credibility to forecast the performance of swimming pool ASHP water heater. Also, this robust mathematical model can be used by an energy service company and system manufacturer to compute the dynamic coefficient of performance of the swimming pool ASHP water heater. Following the above-mentioned information, the research sought to provide a permanent solution to the Eskom evening peak constraint. This is because energy-efficiency, serves as the bridging block between conventional and renewable energy sources needed by Eskom in a bid to provide a balance energy mix and sustainable energy. The implementation of a swimming pool ASHP water heater guaranteed a conducive environment for the population due to the reduction in environmental pollution.
- Full Text:
- Date Issued: 2017
- Authors: Mqayi, Singatha
- Date: 2017
- Subjects: Water heaters Heat pumps Swimming pools -- Heating and ventilation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4835 , vital:28532
- Description: Globally, there is growing concern about energy consumption and its diverse effects on the environment. In South Africa, the current status quo is unfavourable in the domain of energy, hence the Department of Energy, Eskom and NERSA have embarked on supporting energy efficiency technologies nationwide as a strategic goal in reducing demand on the national grid. Due to the non conservative consumption of electricity from the grid and the insufficient supply to meet its demand, the importation of crude oil is very certain. In addition, the current and most popular technology for pool water heating in the said country is the resistive element which is inefficient and non-cost-effective. The energy consumption of residential swimming pool water heating is very massive, and tariff structure shows a constant rise. Furthermore, there's a current electricity crisis during the Eskom evening peak. Hence, a reliable, efficient, cost-effective and renewable energy technology such as an air source heat pump is required as a retrofit to the existing resistive element. Furthermore, mathematical modelling is a tool that can be used to mimic the dynamic behaviour of a physical or process system. It is a computational language or mathematical equation used to predict the dynamic behaviour of physical systems [Tangwe et al., 2015]. Various methods such as numerical methods have been considered as the particular types of mathematical modelling which have been employed to predict the performance of swimming pool ASHP water heater. However, they were unreliable and expensive. Consequently, this research focused on the experimental determination of the viability and development of a mathematical model to predict the performance of swimming pool ASHP water heater. The benefit of the development and building of this model was attributed to its low cost and credibility to forecast the performance of swimming pool ASHP water heater. Also, this robust mathematical model can be used by an energy service company and system manufacturer to compute the dynamic coefficient of performance of the swimming pool ASHP water heater. Following the above-mentioned information, the research sought to provide a permanent solution to the Eskom evening peak constraint. This is because energy-efficiency, serves as the bridging block between conventional and renewable energy sources needed by Eskom in a bid to provide a balance energy mix and sustainable energy. The implementation of a swimming pool ASHP water heater guaranteed a conducive environment for the population due to the reduction in environmental pollution.
- Full Text:
- Date Issued: 2017
Exploring the attitudes of selected community members on the interplay between incidences of poverty and the escalation of HIV/AIDS in Cofimvaba, Eastern Cape Province, South Africa
- Authors: Mrashula, Zodidi
- Date: 2017
- Subjects: AIDS (Disease) -- South Africa -- Eastern Cape AIDS (Disease) -- Economic aspects Poverty -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/7941 , vital:30987
- Description: Cofimvaba has had a noticeable increase of people who got infected with HIV/AIDS and is one of the poorest of the poor in the Eastern Cape. Hence, the researcher became interested to investigate the interplay between incidences of poverty and the prevalence of HIV/AIDS. The reasons for the continued increase of HIV infection in Cofimvaba were investigated. The study used a qualitative approach, was descriptive and explorative and specifically used a case study as a specific research design. The study investigated 32 participants, nine of whom were infected and diagnosed to be seropositive between the years 2012, and 2014; six community members; twelve from the volunteer care givers who were members from the support group. The study also investigated a number of key informants who included a traditional leader, a care giver, a nurse, a social worker and a community development practitioner. The study used a non-probability sampling methodology, but specifically purposive sampling technique. On data collection, the study triangulated both in-depth interviews and focus group discussions. The findings of the study revealed that people who are infected with HIV/AIDS are unemployed, illiterate and suffer from poverty. The study also found that poor people are more vulnerable to HIV/AIDS infections. The study findings were as follows: There is a lack knowledge about HIV/AIDS that leads to lack of prevention. It has been discovered that there is a high level of poverty and HIV/AIDS in Cofimvaba. High level of unemployment is a contributing factor of poverty and high level of HIV/AIDS in Cofimvaba. Level of unprotected sex as driver of HIV/AIDS has also been identified. There is an inextricable relationship poverty and prevalence of HIV/AIDS. Unreliability of the food parcel on people who are HIV positive leads to poverty. The study findings were also as: Caregivers breaching the ethos and principle of confidentiality leads to people not to to HIV/disclose their HIV/AIDS status. Migration driving vulnerability to HIV/AIDS. It has been insisted that transactional sex drives to HIV/AIDS. Low HIV/AIDS education makes people to be vulnerable to HIVAIDS., The fear of testing makes people unaware of their HIV/AIDS status. Also the excessive alcohol intake as a driver to HIV/AIDS vulnerability. It has also been noted that only women responded to the study and there was a high rate of death revealed on account of HIV/AIDS in Cofimvaba. The researcher has also made the following recommendations to the study: obligatory psychol-social support programs for PLWHA, extension and replication of community based organisation, collaboration between different stakeholders in the HIV/AIDS domain. Widen the horizon of training education and HIV/AIDS awareness campaigns and availability of counselling, job opportunity, social grants and food parcels.
- Full Text:
- Date Issued: 2017
- Authors: Mrashula, Zodidi
- Date: 2017
- Subjects: AIDS (Disease) -- South Africa -- Eastern Cape AIDS (Disease) -- Economic aspects Poverty -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/7941 , vital:30987
- Description: Cofimvaba has had a noticeable increase of people who got infected with HIV/AIDS and is one of the poorest of the poor in the Eastern Cape. Hence, the researcher became interested to investigate the interplay between incidences of poverty and the prevalence of HIV/AIDS. The reasons for the continued increase of HIV infection in Cofimvaba were investigated. The study used a qualitative approach, was descriptive and explorative and specifically used a case study as a specific research design. The study investigated 32 participants, nine of whom were infected and diagnosed to be seropositive between the years 2012, and 2014; six community members; twelve from the volunteer care givers who were members from the support group. The study also investigated a number of key informants who included a traditional leader, a care giver, a nurse, a social worker and a community development practitioner. The study used a non-probability sampling methodology, but specifically purposive sampling technique. On data collection, the study triangulated both in-depth interviews and focus group discussions. The findings of the study revealed that people who are infected with HIV/AIDS are unemployed, illiterate and suffer from poverty. The study also found that poor people are more vulnerable to HIV/AIDS infections. The study findings were as follows: There is a lack knowledge about HIV/AIDS that leads to lack of prevention. It has been discovered that there is a high level of poverty and HIV/AIDS in Cofimvaba. High level of unemployment is a contributing factor of poverty and high level of HIV/AIDS in Cofimvaba. Level of unprotected sex as driver of HIV/AIDS has also been identified. There is an inextricable relationship poverty and prevalence of HIV/AIDS. Unreliability of the food parcel on people who are HIV positive leads to poverty. The study findings were also as: Caregivers breaching the ethos and principle of confidentiality leads to people not to to HIV/disclose their HIV/AIDS status. Migration driving vulnerability to HIV/AIDS. It has been insisted that transactional sex drives to HIV/AIDS. Low HIV/AIDS education makes people to be vulnerable to HIVAIDS., The fear of testing makes people unaware of their HIV/AIDS status. Also the excessive alcohol intake as a driver to HIV/AIDS vulnerability. It has also been noted that only women responded to the study and there was a high rate of death revealed on account of HIV/AIDS in Cofimvaba. The researcher has also made the following recommendations to the study: obligatory psychol-social support programs for PLWHA, extension and replication of community based organisation, collaboration between different stakeholders in the HIV/AIDS domain. Widen the horizon of training education and HIV/AIDS awareness campaigns and availability of counselling, job opportunity, social grants and food parcels.
- Full Text:
- Date Issued: 2017
Screening of shark liver extracts for potential antimicrobial properties against selected pathogenic bacterial strains
- Authors: Mrwetyana, Thandolwethu
- Date: 2017
- Subjects: Fishes -- Diseases Pathogenic bacteria Antibiotics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12982 , vital:39413
- Description: The growing problem of antimicrobial resistance prevents the effective treatment of bacterial infections. Traditional antibiotics such as penicillin have been rendered ineffective against most microbial pathogens. This has led to an increased need for the development of new and improved drugs. The marine environment contains a great array of organisms with unique biological properties, but still remains one of our most underutilized biological resources. The aim of this study was to screen different shark liver extracts for antimicrobial properties. After optimizing the extraction methods, the liver extracts (oil and aminosterol) of three different shark species, namely the Dogfish (Squalus acanthias), the Catshark (Scyliorhinus capensis) and the Hammerhead (Sphyrna zygaena) shark, were screened for antimicrobial properties using the Kirby-Bauer disc diffusion method against selected bacterial pathogens (Helicobacter pylori, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus cereus), after which the MIC was determined using the modified broth micro-dilution described by Vollekova et al. (2001). The most active extract was fractionated using thin layer chromatography, and TLC-direct bioautography was used to determine the antimicrobial properties of the fractionated compounds. The Folch et al and the Shinnar et al methods yielded the highest extract volumes for oil and aminosterol consecutively, and the catshark and dogfish aminosterol extract showed greater levels of bioactivity against all selected bacterial pathogens, with S. aureus showing highest susceptibility levels to both extracts. A total of 22 compounds were observed in the developed plates with two compounds (Rf 0.53 and 0.79) showing antimicrobial activity. Certain shark liver extracts possess antimicrobial properties that have the potential to be used in the development of new antimicrobial drugs.
- Full Text:
- Date Issued: 2017
- Authors: Mrwetyana, Thandolwethu
- Date: 2017
- Subjects: Fishes -- Diseases Pathogenic bacteria Antibiotics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12982 , vital:39413
- Description: The growing problem of antimicrobial resistance prevents the effective treatment of bacterial infections. Traditional antibiotics such as penicillin have been rendered ineffective against most microbial pathogens. This has led to an increased need for the development of new and improved drugs. The marine environment contains a great array of organisms with unique biological properties, but still remains one of our most underutilized biological resources. The aim of this study was to screen different shark liver extracts for antimicrobial properties. After optimizing the extraction methods, the liver extracts (oil and aminosterol) of three different shark species, namely the Dogfish (Squalus acanthias), the Catshark (Scyliorhinus capensis) and the Hammerhead (Sphyrna zygaena) shark, were screened for antimicrobial properties using the Kirby-Bauer disc diffusion method against selected bacterial pathogens (Helicobacter pylori, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus cereus), after which the MIC was determined using the modified broth micro-dilution described by Vollekova et al. (2001). The most active extract was fractionated using thin layer chromatography, and TLC-direct bioautography was used to determine the antimicrobial properties of the fractionated compounds. The Folch et al and the Shinnar et al methods yielded the highest extract volumes for oil and aminosterol consecutively, and the catshark and dogfish aminosterol extract showed greater levels of bioactivity against all selected bacterial pathogens, with S. aureus showing highest susceptibility levels to both extracts. A total of 22 compounds were observed in the developed plates with two compounds (Rf 0.53 and 0.79) showing antimicrobial activity. Certain shark liver extracts possess antimicrobial properties that have the potential to be used in the development of new antimicrobial drugs.
- Full Text:
- Date Issued: 2017
Development and validation of DNA barcoding for biodiversity assessment and conservation of red algae in the Algoa Bay region
- Authors: Mshiywa, Faith Masilive
- Date: 2017
- Subjects: Red algae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9011 , vital:34182
- Description: DNA barcoding is a molecular technique that uses a short DNA sequence for species identification. It harnesses global community efforts to establish large-scale public reference libraries to allow species identification. Red algae are a complex group of species and are difficult to identify on morphological grounds only. Red algae have the highest production of halogenated compounds, and are used in the medical and pharmaceutical industries. This study therefore aimed at developing DNA barcodes, universal primers and a Kenton-on-Sea red algae species list, which will aid as a baseline for red algae biodiversity and conservation research. A potential DNA barcode region was designed from the rbcL gene, because rbcL is easy to amplify, easy to sequence and it can differentiate organisms to species level. Primers were designed from multiple red algae rbcL sequences and they were evaluated using bioinformatics tools. Red algae from the Algoa Bay region were screened with these primers and a 77% PCR amplification success was obtained. The PCR products were sequenced and 96% of the amplicons were successfully sequenced and resulted in a barcode sequence length above 700bp, which could be used to identify red algae species. Twenty-six (26) red algae species from Kenton-on-Sea, near Algoa Bay, were successfully identified using the Barcode sequence amplified from a primer set developed from the rbcL gene and were uploaded on the BOLD database for public access. This barcode is, therefore, suitable for use by the South African National Biodiversity Institute or other marine researchers, to identify South African red algae species and ensure the maintenance of their biodiversity and conservation.
- Full Text:
- Date Issued: 2017
- Authors: Mshiywa, Faith Masilive
- Date: 2017
- Subjects: Red algae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9011 , vital:34182
- Description: DNA barcoding is a molecular technique that uses a short DNA sequence for species identification. It harnesses global community efforts to establish large-scale public reference libraries to allow species identification. Red algae are a complex group of species and are difficult to identify on morphological grounds only. Red algae have the highest production of halogenated compounds, and are used in the medical and pharmaceutical industries. This study therefore aimed at developing DNA barcodes, universal primers and a Kenton-on-Sea red algae species list, which will aid as a baseline for red algae biodiversity and conservation research. A potential DNA barcode region was designed from the rbcL gene, because rbcL is easy to amplify, easy to sequence and it can differentiate organisms to species level. Primers were designed from multiple red algae rbcL sequences and they were evaluated using bioinformatics tools. Red algae from the Algoa Bay region were screened with these primers and a 77% PCR amplification success was obtained. The PCR products were sequenced and 96% of the amplicons were successfully sequenced and resulted in a barcode sequence length above 700bp, which could be used to identify red algae species. Twenty-six (26) red algae species from Kenton-on-Sea, near Algoa Bay, were successfully identified using the Barcode sequence amplified from a primer set developed from the rbcL gene and were uploaded on the BOLD database for public access. This barcode is, therefore, suitable for use by the South African National Biodiversity Institute or other marine researchers, to identify South African red algae species and ensure the maintenance of their biodiversity and conservation.
- Full Text:
- Date Issued: 2017
The study of blockchain towards its application to South African Social Security Agency (SASSA)
- Authors: Mthethwa, Sthembile
- Date: 2017
- Subjects: South African Social Security Agency Electronic funds transfers -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12610 , vital:39292
- Description: In recent years, there has been a rapid improvement in the way currencies are perceived, which has led to a rise in digital currencies commonly known as cryptocurrencies (because they are secured by the use of cryptography). Bitcoin was the _rst successful cryptocurrency which allowed users to transact directly with each other without the involvement of the third party (the bank). Bitcoin introduced a new technology known as the blockchain which is considered to be the ext-generation technology". Blockchain is a chronological database used to store all the transactions that have occurred since the inception of Bitcoin. A study of the Blockchain involving its application to the South African Social Security Agency (SASSA) is presented. This study assesses how the Blockchain functions. The Blockchain has been viewed as the next-generation technology. This study also assesses the application of the Blockchain to other systems other than cryptocurrencies or digital currencies. Recent studies in the literature have proposed applications of the Blockchain to other system (e.g. electronic voting, smart contracts, and intellectual property rights). Although these proposals have been put forward, none has been made speci_cally for SASSA. This study also presents the problems that the Blockchain has (e.g. scalability, security).Recent literature has tried to solve the problem of scalability, by introducing new protocols like mini-blockchain. In addition, this study presents the challenges that SASSA is currently having and it provides details about the attacks that could succeed in the system. The study presents the analysis of the blockchain for its application to SASSA; the analysis includes scalability, performance and security. Based on the analysis, it is shown that the blockchain is not compatible to be applied to SASSA. However, this study proposes a solution to some of the challenges SASSA is currently facing.
- Full Text:
- Date Issued: 2017
- Authors: Mthethwa, Sthembile
- Date: 2017
- Subjects: South African Social Security Agency Electronic funds transfers -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12610 , vital:39292
- Description: In recent years, there has been a rapid improvement in the way currencies are perceived, which has led to a rise in digital currencies commonly known as cryptocurrencies (because they are secured by the use of cryptography). Bitcoin was the _rst successful cryptocurrency which allowed users to transact directly with each other without the involvement of the third party (the bank). Bitcoin introduced a new technology known as the blockchain which is considered to be the ext-generation technology". Blockchain is a chronological database used to store all the transactions that have occurred since the inception of Bitcoin. A study of the Blockchain involving its application to the South African Social Security Agency (SASSA) is presented. This study assesses how the Blockchain functions. The Blockchain has been viewed as the next-generation technology. This study also assesses the application of the Blockchain to other systems other than cryptocurrencies or digital currencies. Recent studies in the literature have proposed applications of the Blockchain to other system (e.g. electronic voting, smart contracts, and intellectual property rights). Although these proposals have been put forward, none has been made speci_cally for SASSA. This study also presents the problems that the Blockchain has (e.g. scalability, security).Recent literature has tried to solve the problem of scalability, by introducing new protocols like mini-blockchain. In addition, this study presents the challenges that SASSA is currently having and it provides details about the attacks that could succeed in the system. The study presents the analysis of the blockchain for its application to SASSA; the analysis includes scalability, performance and security. Based on the analysis, it is shown that the blockchain is not compatible to be applied to SASSA. However, this study proposes a solution to some of the challenges SASSA is currently facing.
- Full Text:
- Date Issued: 2017
Quality management systems – a fundamental business imperative for construction companies: a case study of Bay West city mall
- Mthi, Vuyolwethu Feza Philisa
- Authors: Mthi, Vuyolwethu Feza Philisa
- Date: 2017
- Subjects: Construction projects -- Management Construction industry -- Management , Total quality management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/45908 , vital:39319
- Description: The quality of construction projects in South Africa has long been below par which is evident in the reports of poor project performance, poorly implemented construction processes, or even worse projects delivered at an unexpected cost to the client. Private and public sector clients are dissatisfied with the quality of work produced by contractors whilst the rectification of substandard construction work on many of the low-cost housing projects throughout South Africa has left the state with a bill of around R50 billion. As a result this research suggests that company’s implement quality management systems as a means to differentiate and elevate themselves above current industry performance. The research inquiry was conducted through the use of a case study (Bay West City Mall). Data was collected primarily through participant observation and survey questionnaires with the various participants on the Bay West City Mall project. The collected data were extracted, errors eliminated/accounted for, coded and entered onto an excel spreadsheet for easy reference and analysis. For the interpretation of the data the researcher used the bivariate tabulation method where categorical data is measured using ordinal and nominal scales. The study concluded that the employment of quality management systems should no longer be seen as optional but as fundamental to the continual improvement of construction companies, those organizations that fully institutionalise the principles of quality management will have a strong chance of improving their project performance, reducing project costs, getting repeat business and increasing profits on projects. It is the recommendation of this study that more research be conducted into how quality management, in the construction industry, can assist in alleviating other problems that plague the South African construction industry such as poor performance relating to health & safety, cost, time, low profit margins and poor cultural practices.
- Full Text:
- Date Issued: 2017
- Authors: Mthi, Vuyolwethu Feza Philisa
- Date: 2017
- Subjects: Construction projects -- Management Construction industry -- Management , Total quality management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/45908 , vital:39319
- Description: The quality of construction projects in South Africa has long been below par which is evident in the reports of poor project performance, poorly implemented construction processes, or even worse projects delivered at an unexpected cost to the client. Private and public sector clients are dissatisfied with the quality of work produced by contractors whilst the rectification of substandard construction work on many of the low-cost housing projects throughout South Africa has left the state with a bill of around R50 billion. As a result this research suggests that company’s implement quality management systems as a means to differentiate and elevate themselves above current industry performance. The research inquiry was conducted through the use of a case study (Bay West City Mall). Data was collected primarily through participant observation and survey questionnaires with the various participants on the Bay West City Mall project. The collected data were extracted, errors eliminated/accounted for, coded and entered onto an excel spreadsheet for easy reference and analysis. For the interpretation of the data the researcher used the bivariate tabulation method where categorical data is measured using ordinal and nominal scales. The study concluded that the employment of quality management systems should no longer be seen as optional but as fundamental to the continual improvement of construction companies, those organizations that fully institutionalise the principles of quality management will have a strong chance of improving their project performance, reducing project costs, getting repeat business and increasing profits on projects. It is the recommendation of this study that more research be conducted into how quality management, in the construction industry, can assist in alleviating other problems that plague the South African construction industry such as poor performance relating to health & safety, cost, time, low profit margins and poor cultural practices.
- Full Text:
- Date Issued: 2017
Thermoluminescence of synthetic quartz annealed beyond its second phase inversion temperature
- Authors: Mthwesi, Zuko
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/46077 , vital:25577
- Description: Thermoluminescence of synthetic quartz annealed at 1000 ºC for 10 minutes has been studied. The aim was to study mechanisms of thermoluminescence in annealed synthetic quartz and to discuss the results in terms of the physics of point defects. The sample was irradiated with a beta dose of 10 Gy of beta radiation and then heated at a linear heating rate of 1 ºC.s-1 up to 500 ºC. The thermoluminescence (TL) glow curve consists of three glow peaks. Peak I at 74 0C (main peak) with high intensity as compared to the other two peaks. Peak II at 144 ºC is more intense than peak III at 180 ºC. This study was on the main peak (MP) at 74 ºC and peak III at 180 ºC. Kinetic analysis was carried out to determine the trap depth E, frequency factor s and the order of kinetics b of both peaks using the initial rise, peak shape, variable heating rate, glow curve deconvolution and isothermal TL methods. The values of kinetic parameters obtained were around 0.7 to 1.0 eV for trap depth and in the interval of 108 to 1015 s-¹ for frequency factor for both peaks. The effect of heating rate from 0.5 to 5 ºC.s-¹ on the TL peak intensity and peak temperature was observed. Also the effect of thermal quenching was observed at high heating rates. Since the TL glow curve has overlapping TL peaks, the Tm-Tstop method from 54 ºC up to 64 ºC and E -Tstop methods were introduced where a first order single peak was observed. Phototransfered thermoluminescence (PTTL) was investigated and characterized by three peaks. First PTTL peak I at 72 ºC, peak II at 134 ºC and peak III at 176 ºC. Analysis was carried out on peaks I and III for the effect of dose dependence from 20-200 Gy. Thermal fading was observed on PTTL peaks I and III, after storage time of 30 minutes.
- Full Text:
- Date Issued: 2017
- Authors: Mthwesi, Zuko
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/46077 , vital:25577
- Description: Thermoluminescence of synthetic quartz annealed at 1000 ºC for 10 minutes has been studied. The aim was to study mechanisms of thermoluminescence in annealed synthetic quartz and to discuss the results in terms of the physics of point defects. The sample was irradiated with a beta dose of 10 Gy of beta radiation and then heated at a linear heating rate of 1 ºC.s-1 up to 500 ºC. The thermoluminescence (TL) glow curve consists of three glow peaks. Peak I at 74 0C (main peak) with high intensity as compared to the other two peaks. Peak II at 144 ºC is more intense than peak III at 180 ºC. This study was on the main peak (MP) at 74 ºC and peak III at 180 ºC. Kinetic analysis was carried out to determine the trap depth E, frequency factor s and the order of kinetics b of both peaks using the initial rise, peak shape, variable heating rate, glow curve deconvolution and isothermal TL methods. The values of kinetic parameters obtained were around 0.7 to 1.0 eV for trap depth and in the interval of 108 to 1015 s-¹ for frequency factor for both peaks. The effect of heating rate from 0.5 to 5 ºC.s-¹ on the TL peak intensity and peak temperature was observed. Also the effect of thermal quenching was observed at high heating rates. Since the TL glow curve has overlapping TL peaks, the Tm-Tstop method from 54 ºC up to 64 ºC and E -Tstop methods were introduced where a first order single peak was observed. Phototransfered thermoluminescence (PTTL) was investigated and characterized by three peaks. First PTTL peak I at 72 ºC, peak II at 134 ºC and peak III at 176 ºC. Analysis was carried out on peaks I and III for the effect of dose dependence from 20-200 Gy. Thermal fading was observed on PTTL peaks I and III, after storage time of 30 minutes.
- Full Text:
- Date Issued: 2017
Tillage and crop rotation effects on selected soil properties and wheat yield in a short term field experiment in the Eastern Cape province, South Africa
- Authors: Mtyobile, Mxolisi
- Date: 2017
- Subjects: Crop rotation -- South Africa -- Eastern Cape Cropping systems -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/13414 , vital:39659
- Description: Severe land degradation associated with current conventional production systems have resulted in low production amongst the small scale farmers in the Eastern Cape. Inappropriate management practices cause depletion of organic matter and other essential nutrients leading to a decline in crop productivity. There is growing evidence that conservation agriculture (CA) practices involving no-tillage (NT) coupled with crop rotation and surface residue retention increases soil organic carbon (SOC) and other essential nutrients and therefore has potential to alleviate soil quality deterioration. A study was carried out to investigate the effects of tillage and crop rotation with crop residue retention on selected soil properties and on wheat yield in the Alice Jozini ecotope of the Eastern Cape. Specific objectives were to determine (i) the effect of crop rotation and tillage on soil SOC, NH4, NO3, total N, P, K, Ca, Mg, Zn, soil pH and EC distribution at 0-5 cm, 5 cm -10 cm, 10 cm-20 cm (ii) the effect of crop rotation and tillage on soil bulk density, porosity and on soil water content (iii) the effect of crop rotation and tillage on wheat biomass and grain yield. Treatments were arranged as a split-split plot in a randomized complete block design with three replicates. Tillage treatments included no-tillage (NT) and conventional tillage (CT) and were applied on the main plots while crop rotation treatments were applied as subplots. Crop residue retention treatments were applied as sub-sub plots. The rotational treatments were maize-fallow-maize (MFM), maize-fallow-soybean (MFS), maize-wheat-maize (MWM) and maize-wheat-soybean (MWS). However, the current study focused on tillage and crop rotation treatments under residue retention to give 8 treatments. Data from the field trials showed that NT with residue retention had significantly (p < 0.05) higher SOC, Total N, P, K, Ca and EC relative to CT. The MWS rotation under no-tillage (NT) with residue retention followed by MFS resulted in the progressive improvement in soil nutrient status. The correlations of SOC with various soil nutrients under study showed that the nature of the relationships between SOC and nutrient availability was consistent. Results on soil physical parameters showed that tillage had no significant effect (p > 0.05) on soil bulk density (ρb) and porosity whereas a significant effect on soil water content under NT was observed. Crop rotation had no significant effects (p > 0.05) on soil bulk density, porosity and soil moisture across the tillage treatments. The MWS rotation registered an increase in soil porosity in comparison with the MWM and MFM. Tillage x crop rotation interaction effects were significant (p < 0.05) on the measured porosity and soil water content. Soil bulk density showed negative correlation with soil porosity and soil water content (SWC) whereas porosity had a positive correlation with SWC. On yield parameters, results revealed that no significant (P>0.05) interaction of main effects with respect to wheat biomass and grain yield. Tillage had a significant (P<0.05) effect on wheat biomass only in season 2. Tillage and crop rotation effects were not significant (P>0.05) with regards to grain yield throughout the experimental period. Higher grain wheat biomass and grain yield were found in MWS rotation under NT with surface residue retention although not statistically significant. Correlation analysis revealed that wheat yield was positively correlated to SOC, P, and Total N. Therefore, combination of NT with MWS rotation with residue retention has the potential to significantly improve soil chemical properties and wheat grain yield whereas MWM followed by MWS crop rotation under NT showed an increase in soil porosity and soil water content.
- Full Text:
- Date Issued: 2017
- Authors: Mtyobile, Mxolisi
- Date: 2017
- Subjects: Crop rotation -- South Africa -- Eastern Cape Cropping systems -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/13414 , vital:39659
- Description: Severe land degradation associated with current conventional production systems have resulted in low production amongst the small scale farmers in the Eastern Cape. Inappropriate management practices cause depletion of organic matter and other essential nutrients leading to a decline in crop productivity. There is growing evidence that conservation agriculture (CA) practices involving no-tillage (NT) coupled with crop rotation and surface residue retention increases soil organic carbon (SOC) and other essential nutrients and therefore has potential to alleviate soil quality deterioration. A study was carried out to investigate the effects of tillage and crop rotation with crop residue retention on selected soil properties and on wheat yield in the Alice Jozini ecotope of the Eastern Cape. Specific objectives were to determine (i) the effect of crop rotation and tillage on soil SOC, NH4, NO3, total N, P, K, Ca, Mg, Zn, soil pH and EC distribution at 0-5 cm, 5 cm -10 cm, 10 cm-20 cm (ii) the effect of crop rotation and tillage on soil bulk density, porosity and on soil water content (iii) the effect of crop rotation and tillage on wheat biomass and grain yield. Treatments were arranged as a split-split plot in a randomized complete block design with three replicates. Tillage treatments included no-tillage (NT) and conventional tillage (CT) and were applied on the main plots while crop rotation treatments were applied as subplots. Crop residue retention treatments were applied as sub-sub plots. The rotational treatments were maize-fallow-maize (MFM), maize-fallow-soybean (MFS), maize-wheat-maize (MWM) and maize-wheat-soybean (MWS). However, the current study focused on tillage and crop rotation treatments under residue retention to give 8 treatments. Data from the field trials showed that NT with residue retention had significantly (p < 0.05) higher SOC, Total N, P, K, Ca and EC relative to CT. The MWS rotation under no-tillage (NT) with residue retention followed by MFS resulted in the progressive improvement in soil nutrient status. The correlations of SOC with various soil nutrients under study showed that the nature of the relationships between SOC and nutrient availability was consistent. Results on soil physical parameters showed that tillage had no significant effect (p > 0.05) on soil bulk density (ρb) and porosity whereas a significant effect on soil water content under NT was observed. Crop rotation had no significant effects (p > 0.05) on soil bulk density, porosity and soil moisture across the tillage treatments. The MWS rotation registered an increase in soil porosity in comparison with the MWM and MFM. Tillage x crop rotation interaction effects were significant (p < 0.05) on the measured porosity and soil water content. Soil bulk density showed negative correlation with soil porosity and soil water content (SWC) whereas porosity had a positive correlation with SWC. On yield parameters, results revealed that no significant (P>0.05) interaction of main effects with respect to wheat biomass and grain yield. Tillage had a significant (P<0.05) effect on wheat biomass only in season 2. Tillage and crop rotation effects were not significant (P>0.05) with regards to grain yield throughout the experimental period. Higher grain wheat biomass and grain yield were found in MWS rotation under NT with surface residue retention although not statistically significant. Correlation analysis revealed that wheat yield was positively correlated to SOC, P, and Total N. Therefore, combination of NT with MWS rotation with residue retention has the potential to significantly improve soil chemical properties and wheat grain yield whereas MWM followed by MWS crop rotation under NT showed an increase in soil porosity and soil water content.
- Full Text:
- Date Issued: 2017
Evaluating the importance of mangroves as fish nurseries in selected warm temperate South African estuaries
- Authors: Muller, Cuen
- Date: 2017
- Subjects: Mangrove ecology -- South Africa Mangrove fisheries -- South Africa , Estuarine ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/12080 , vital:27029
- Description: The value of mangrove habitats as fish nurseries was assessed by comparing communities of early stage and juvenile fishes between estuaries with and without mangroves. Early stage fishes were sampled using boat-based plankton towing while juveniles were sampled by seine netting. Sampling took place at five sites spaced 1 km apart starting near the estuary mouth in four estuaries along the temperate coastline of the Eastern Cape Province of South Africa. Four estuaries were selected based on shared similarities which included catchment area, estuarine area and shared habitats barring the presence of mangroves which occupied the river margins of two systems. Results revealed that early stage and juvenile fish communities (both marine- and estuary-spawned) were similar between systems with and without mangrove habitats. Differences in fish communities among estuaries were rather attributed to axial salinity gradients associated with greater freshwater input, while season and temperature produced significant variances in fish densities with Generalised Additive Models revealing responses of communities to these variables. A common estuarine-dependent fish, Rhabdosargus holubi (Family Sparidae), was further investigated to determine habitat use, residency and dietary patterns in different mangrove habitats. High habitat residency in this species was revealed during a short-term tagging study using Visible Implant Elastomer tags and long-term isotope analysis in juveniles sampled from two contrasting mangrove habitats. A wider feeding niche was observed in an eelgrass-red mangrove connected habitat when compared with more exposed white mangrove areas. Low dependence on mangrove habitats in temperate estuaries is likely due to their tidally dominated inundation and limited refuge potential due to smaller area coverage by mangroves in temperate estuaries. Relatively lower primary productivity in warm temperate mangrove areas, relative to their tropical counterparts, provides no significant feeding advantage or refuge opportunities relative to other available habitats in these estuaries. Warm temperate estuaries, which are both spatially and temporally highly variable, instead host species which are habitat generalists, able to capitalise on these highly dynamic environments.
- Full Text:
- Date Issued: 2017
- Authors: Muller, Cuen
- Date: 2017
- Subjects: Mangrove ecology -- South Africa Mangrove fisheries -- South Africa , Estuarine ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/12080 , vital:27029
- Description: The value of mangrove habitats as fish nurseries was assessed by comparing communities of early stage and juvenile fishes between estuaries with and without mangroves. Early stage fishes were sampled using boat-based plankton towing while juveniles were sampled by seine netting. Sampling took place at five sites spaced 1 km apart starting near the estuary mouth in four estuaries along the temperate coastline of the Eastern Cape Province of South Africa. Four estuaries were selected based on shared similarities which included catchment area, estuarine area and shared habitats barring the presence of mangroves which occupied the river margins of two systems. Results revealed that early stage and juvenile fish communities (both marine- and estuary-spawned) were similar between systems with and without mangrove habitats. Differences in fish communities among estuaries were rather attributed to axial salinity gradients associated with greater freshwater input, while season and temperature produced significant variances in fish densities with Generalised Additive Models revealing responses of communities to these variables. A common estuarine-dependent fish, Rhabdosargus holubi (Family Sparidae), was further investigated to determine habitat use, residency and dietary patterns in different mangrove habitats. High habitat residency in this species was revealed during a short-term tagging study using Visible Implant Elastomer tags and long-term isotope analysis in juveniles sampled from two contrasting mangrove habitats. A wider feeding niche was observed in an eelgrass-red mangrove connected habitat when compared with more exposed white mangrove areas. Low dependence on mangrove habitats in temperate estuaries is likely due to their tidally dominated inundation and limited refuge potential due to smaller area coverage by mangroves in temperate estuaries. Relatively lower primary productivity in warm temperate mangrove areas, relative to their tropical counterparts, provides no significant feeding advantage or refuge opportunities relative to other available habitats in these estuaries. Warm temperate estuaries, which are both spatially and temporally highly variable, instead host species which are habitat generalists, able to capitalise on these highly dynamic environments.
- Full Text:
- Date Issued: 2017
Population genomics analysis of yellowfin tuna Thunnus albacares off South Africa reveals need for a shifted management boundary
- Authors: Mullins, Rachel Brenna
- Date: 2017
- Subjects: Yellowfin tuna fisheries -- South Africa -- Western Cape , Genomics , Tuna fisheries -- South Africa , Fishery management -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/57819 , vital:26992
- Description: Yellowfin tuna Thunnus albacares is a commercially and economically important fisheries species, which comprises the second largest component of South Africa’s catch of tuna and tuna-like species. Catches of the species off South Africa are treated as two discrete stocks by the two tuna Regional Fisheries Management Organisations (tRFMOs) under whose jurisdictions they fall. Individuals caught off the Western Cape, west of the boundary between the tRFMOs at 20°E, are included in assessment and management of the Atlantic Ocean yellowfin tuna stock by the International Commission for the Conservation of Atlantic Tunas (ICCAT), and those caught east of this boundary are assessed and managed as part of the Indian Ocean stock by the Indian Ocean Tuna Commission (IOTC). The boundary between these stocks is based on the confluence of the two oceans in this region and does not incorporate the population structure of species. For sustainable exploitation of fisheries resources, it is important that the definition of management stocks reflects species’ biological population structure; the fine-scale stock structure of yellowfin tuna off South Africa is therefore a research priority which this study aimed to address by means of population genomics analyses. Yellowfin tuna exhibit shallow genetic differentiation over wide geographic areas, and as such traditional population genetic approaches have limited power in resolving fishery significant population structure in the species. Herein, a population genomic approach was employed, specifically, genome-wide analysis of single nucleotide polymorphisms (SNPs) discovered using a next-generation DNA sequencing approach, to confer (i) increased statistical power to detect neutral structuring reflecting population connectivity patterns and (ii) signatures of local adaptation. The mitochondrial Control Region (mtDNA CR) was also sequenced to compare the resolving power of different approaches and to permit coalescent based analyses of the species evolutionary history in the region. Neutral SNP loci revealed significant structure within the dataset (Fst=0.0043; P<0.0001); partitioning of this differentiation within the dataset indicated significant differentiation between yellowfin tuna from the Western Cape and the Gulf of Guinea in the eastern Atlantic Ocean, with no significant differentiation between individuals from the Western Cape and Western Indian Ocean regions. This indicates two population units wherein there is a separation of the Gulf of Guinea from the remaining samples (Indian Ocean including Western Cape) that are largely derived from a single genetic population. This pattern was also supported by assignment tests. Positive outlier SNPs, exhibiting signatures of diversifying selection, suggest that individuals from these regions may be locally adapted, as well as demographically isolated. The mtDNA CR did not reveal any significant genetic structure among samples (Fst=0.0030; P=0.309), demonstrating the increased resolving power provided by population genomics approaches, but revealed signatures of historical demographic fluctuations associated with glacial cycles. Based on the findings of this study, it is suggested that yellowfin tuna caught off the Western Cape of South Africa are migrants from the Indian Ocean population, exhibiting significant genetic differentiation from the Atlantic Ocean Gulf of Guinea individuals, and should thus be included in the assessment and management of the Indian Ocean stock. It is therefore recommended that the boundary between the Atlantic and Indian Ocean yellowfin tuna stocks, under the mandates of ICCAT and the IOTC respectively, should be shifted to approximately 13.35°E to include all individuals caught in South African waters in the Indian Ocean stock.
- Full Text:
- Date Issued: 2017
- Authors: Mullins, Rachel Brenna
- Date: 2017
- Subjects: Yellowfin tuna fisheries -- South Africa -- Western Cape , Genomics , Tuna fisheries -- South Africa , Fishery management -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/57819 , vital:26992
- Description: Yellowfin tuna Thunnus albacares is a commercially and economically important fisheries species, which comprises the second largest component of South Africa’s catch of tuna and tuna-like species. Catches of the species off South Africa are treated as two discrete stocks by the two tuna Regional Fisheries Management Organisations (tRFMOs) under whose jurisdictions they fall. Individuals caught off the Western Cape, west of the boundary between the tRFMOs at 20°E, are included in assessment and management of the Atlantic Ocean yellowfin tuna stock by the International Commission for the Conservation of Atlantic Tunas (ICCAT), and those caught east of this boundary are assessed and managed as part of the Indian Ocean stock by the Indian Ocean Tuna Commission (IOTC). The boundary between these stocks is based on the confluence of the two oceans in this region and does not incorporate the population structure of species. For sustainable exploitation of fisheries resources, it is important that the definition of management stocks reflects species’ biological population structure; the fine-scale stock structure of yellowfin tuna off South Africa is therefore a research priority which this study aimed to address by means of population genomics analyses. Yellowfin tuna exhibit shallow genetic differentiation over wide geographic areas, and as such traditional population genetic approaches have limited power in resolving fishery significant population structure in the species. Herein, a population genomic approach was employed, specifically, genome-wide analysis of single nucleotide polymorphisms (SNPs) discovered using a next-generation DNA sequencing approach, to confer (i) increased statistical power to detect neutral structuring reflecting population connectivity patterns and (ii) signatures of local adaptation. The mitochondrial Control Region (mtDNA CR) was also sequenced to compare the resolving power of different approaches and to permit coalescent based analyses of the species evolutionary history in the region. Neutral SNP loci revealed significant structure within the dataset (Fst=0.0043; P<0.0001); partitioning of this differentiation within the dataset indicated significant differentiation between yellowfin tuna from the Western Cape and the Gulf of Guinea in the eastern Atlantic Ocean, with no significant differentiation between individuals from the Western Cape and Western Indian Ocean regions. This indicates two population units wherein there is a separation of the Gulf of Guinea from the remaining samples (Indian Ocean including Western Cape) that are largely derived from a single genetic population. This pattern was also supported by assignment tests. Positive outlier SNPs, exhibiting signatures of diversifying selection, suggest that individuals from these regions may be locally adapted, as well as demographically isolated. The mtDNA CR did not reveal any significant genetic structure among samples (Fst=0.0030; P=0.309), demonstrating the increased resolving power provided by population genomics approaches, but revealed signatures of historical demographic fluctuations associated with glacial cycles. Based on the findings of this study, it is suggested that yellowfin tuna caught off the Western Cape of South Africa are migrants from the Indian Ocean population, exhibiting significant genetic differentiation from the Atlantic Ocean Gulf of Guinea individuals, and should thus be included in the assessment and management of the Indian Ocean stock. It is therefore recommended that the boundary between the Atlantic and Indian Ocean yellowfin tuna stocks, under the mandates of ICCAT and the IOTC respectively, should be shifted to approximately 13.35°E to include all individuals caught in South African waters in the Indian Ocean stock.
- Full Text:
- Date Issued: 2017
Post-release evaluation and thermal physiology of the Pereskia stem-wilter, Catorhintha schaffneri (Coreidae), a new biological control agent for Pereskia aculeata (Cactaceae)
- Authors: Muskett, Phillippa Claire
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/36094 , vital:24477
- Description: Catorhintha schaffneri Brailovsky and Garcia (Hemiptera: Coreidae) is a biological control agent that was recently accepted for release in South Africa to control Pereskia aculeata Miller (Cactaceae), an invasive creeping cactus. The aim of this thesis was to conduct post-release research to ensure that C. schaffneri is utilised to its full potential. To achieve this aim, and focus release efforts, the thermal physiology of C. schaffneri was investigated to predict where in South Africa the agent is most likely to establish. These predictions were then tested by releasing the agent at field sites with a wide variety of climatic conditions and evaluating establishment success. When invasive plants invade a wide distribution, made up of areas with different climatic conditions, biological control agents may not establish or be effective throughout the invaded distribution. According to the thermal physiology of C. schaffneri, it is most likely to establish and become effective in the subtropical region of South Africa, along the coast of KwaZulu- Natal. Cold winters, or generally low year-round temperatures, may limit establishment in the more temperate areas of South Africa in the Eastern and Western Cape as well as inland in the Highveld region. These predictions can be used to focus release efforts to climatically suitable regions and stop releases in areas where C. schaffneri cannot survive. Predictions based on thermal physiology may not account for all of the variables which affect establishment. To account for other variables, the establishment of C. schaffneri was tested using closely monitored field release studies. During these studies the effect of other variables such as; microclimate temperature, humidity, precipitation, plant quality and release strategy were considered. Low humidity, precipitation and plant quality appear to affect the establishment of C. schaffneri in the subtropical areas of South Africa. The experiment was conducted during a period of drought, and this may have resulted in lower establishment rates. The most successful release strategy for C. schaffneri was the use of multiple, small releases rather than single releases of the same number of individuals. The field based study was therefore able to improve the biological control of P. aculeata by increasing the chance that each release of C. schaffneri results in establishment. The post-release studies presented in this thesis will increase the impact of C. schaffneri by focussing release efforts to climatically suitable sites, releasing at appropriate times of year and releasing the agent in a manner that increases establishment success. Post-release studies, such as those presented here, can make biological control programmes more efficient and effective.
- Full Text:
- Date Issued: 2017
- Authors: Muskett, Phillippa Claire
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/36094 , vital:24477
- Description: Catorhintha schaffneri Brailovsky and Garcia (Hemiptera: Coreidae) is a biological control agent that was recently accepted for release in South Africa to control Pereskia aculeata Miller (Cactaceae), an invasive creeping cactus. The aim of this thesis was to conduct post-release research to ensure that C. schaffneri is utilised to its full potential. To achieve this aim, and focus release efforts, the thermal physiology of C. schaffneri was investigated to predict where in South Africa the agent is most likely to establish. These predictions were then tested by releasing the agent at field sites with a wide variety of climatic conditions and evaluating establishment success. When invasive plants invade a wide distribution, made up of areas with different climatic conditions, biological control agents may not establish or be effective throughout the invaded distribution. According to the thermal physiology of C. schaffneri, it is most likely to establish and become effective in the subtropical region of South Africa, along the coast of KwaZulu- Natal. Cold winters, or generally low year-round temperatures, may limit establishment in the more temperate areas of South Africa in the Eastern and Western Cape as well as inland in the Highveld region. These predictions can be used to focus release efforts to climatically suitable regions and stop releases in areas where C. schaffneri cannot survive. Predictions based on thermal physiology may not account for all of the variables which affect establishment. To account for other variables, the establishment of C. schaffneri was tested using closely monitored field release studies. During these studies the effect of other variables such as; microclimate temperature, humidity, precipitation, plant quality and release strategy were considered. Low humidity, precipitation and plant quality appear to affect the establishment of C. schaffneri in the subtropical areas of South Africa. The experiment was conducted during a period of drought, and this may have resulted in lower establishment rates. The most successful release strategy for C. schaffneri was the use of multiple, small releases rather than single releases of the same number of individuals. The field based study was therefore able to improve the biological control of P. aculeata by increasing the chance that each release of C. schaffneri results in establishment. The post-release studies presented in this thesis will increase the impact of C. schaffneri by focussing release efforts to climatically suitable sites, releasing at appropriate times of year and releasing the agent in a manner that increases establishment success. Post-release studies, such as those presented here, can make biological control programmes more efficient and effective.
- Full Text:
- Date Issued: 2017
Physiochemical and heavy metals fingerprints of the final effluents of Adelaide and Seymour wastewater treatment facilities in the Eastern Cape, South Africa
- Authors: Mutukwa, Dorcas
- Date: 2017
- Subjects: Water -- Purification Effluent quality -- Testing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8089 , vital:31520
- Description: Wastewater contains pathogens, heavy metals, nutrients, organic matter and other toxic chemicals and when discharged into the environment without proper treatment, it may cause adverse health problems and environment degradation. There have been reports in the Eastern Cape Province, South Africa of inadequate treated wastewater effluents being discharged into freshwater environments. This study reports on the physicochemical and heavy metals qualities for two wastewater treatment facilities in the Eastern Cape, South Africa over a six-month sampling period (September 2015 to February 2016). Wastewater effluent samples were collected from the influents, final effluents and receiving waterbodies as well as sludge samples in replicates. The physicochemical parameters were analysed using standard methods (APHA, 2012). The acid digested heavy metals samples were analysed using Atomic Absorption Spectrophotometer (iCE 3500 Thermo Fisher Spectrometer). The concentrations were compared to recommended limits used in South Africa and World Health Organisation (WHO). Physicochemical qualities assessed at Adelaide wastewater treatment plant ranged as follows: temperature (21.6 - 30.5 oC), turbidity (2.1 – 71.3 NTU), electrical conductivity (EC) (743.0 – 898.3 μ/Scm) and dissolved oxygen (DO) (2.11 – 3.50 mg/L) while the ranges of the parameter assessed at Seymour wastewater treatment plant ranged as follows: chemical dissolved oxygen (COD) (41.7 – 115.3 mg/L), EC (628 and 797.7 μ/Scm) and nitrates (4.6 – 11.0 mg/L. The heavy metals concentration for the final effluents at Adelaide wastewater treatment plant ranged as follows: Cd (0 – 0.002 mg/L), Cu (0 – 0.096 mg/L) and Fe (0 – 0.498 mg/L). Cu concentrations in sludge at Seymour wastewater treatment plant ranged between 83.82 and 132.07 mg/L. Reduction efficiencies of Adelaide in removing chlorides and sulphates were 33 and 36 percent respectively. Findings of study revealed negative impacts of inadequately treated effluents on receiving waterbodies and this puts communities which rely on the water as immediate source of fresh water for domestic purposes at health risk.
- Full Text:
- Date Issued: 2017
- Authors: Mutukwa, Dorcas
- Date: 2017
- Subjects: Water -- Purification Effluent quality -- Testing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8089 , vital:31520
- Description: Wastewater contains pathogens, heavy metals, nutrients, organic matter and other toxic chemicals and when discharged into the environment without proper treatment, it may cause adverse health problems and environment degradation. There have been reports in the Eastern Cape Province, South Africa of inadequate treated wastewater effluents being discharged into freshwater environments. This study reports on the physicochemical and heavy metals qualities for two wastewater treatment facilities in the Eastern Cape, South Africa over a six-month sampling period (September 2015 to February 2016). Wastewater effluent samples were collected from the influents, final effluents and receiving waterbodies as well as sludge samples in replicates. The physicochemical parameters were analysed using standard methods (APHA, 2012). The acid digested heavy metals samples were analysed using Atomic Absorption Spectrophotometer (iCE 3500 Thermo Fisher Spectrometer). The concentrations were compared to recommended limits used in South Africa and World Health Organisation (WHO). Physicochemical qualities assessed at Adelaide wastewater treatment plant ranged as follows: temperature (21.6 - 30.5 oC), turbidity (2.1 – 71.3 NTU), electrical conductivity (EC) (743.0 – 898.3 μ/Scm) and dissolved oxygen (DO) (2.11 – 3.50 mg/L) while the ranges of the parameter assessed at Seymour wastewater treatment plant ranged as follows: chemical dissolved oxygen (COD) (41.7 – 115.3 mg/L), EC (628 and 797.7 μ/Scm) and nitrates (4.6 – 11.0 mg/L. The heavy metals concentration for the final effluents at Adelaide wastewater treatment plant ranged as follows: Cd (0 – 0.002 mg/L), Cu (0 – 0.096 mg/L) and Fe (0 – 0.498 mg/L). Cu concentrations in sludge at Seymour wastewater treatment plant ranged between 83.82 and 132.07 mg/L. Reduction efficiencies of Adelaide in removing chlorides and sulphates were 33 and 36 percent respectively. Findings of study revealed negative impacts of inadequately treated effluents on receiving waterbodies and this puts communities which rely on the water as immediate source of fresh water for domestic purposes at health risk.
- Full Text:
- Date Issued: 2017
Design, construction and performance evaluation of an agitated portable biogas digester under greenhouse-regulated temperature
- Authors: Mutungwazi Asheal
- Date: 2017
- Subjects: Sewage -- Purification -- Anaerobic treatment Green technology Renewable energy sources
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9055 , vital:34222
- Description: Biogas yield in anaerobic digesters is negatively affected by low temperatures during cold seasons and nights, temperature fluctuations and inefficient agitation. Electrical heating and underground digester installations have been used to help minimise these effects but the high cost of electrical heating, infeasibility of underground installations in some terrains, inefficient agitation and difficult maintenance continue to be major set-backs to high biogas yields. In this study a 100 ℓ, agitated, portable carbon steel digester housed within a greenhouse, whose operation temperature is automatically maintained at an optimum of 35 ± 1 oC by means of an ON/OFF electronic circuit for ventilation control through a suitably sized window and insulation offered by an air film trapped in-between a double layer of polyethylene plastic covering of the greenhouse, was designed. Cow dung from a dairy farm at the University of Fort Hare with total solids (TS), volatile solids (VS), chemical oxygen demand (COD) and ammonia nitrogen content of 162348.67 mg/ℓ, 116543.98 mg/ℓ, 37 879 mg/ℓ and 128 - 235 mg/ℓ respectively was used for the performance evaluation of the digester. Analysis of the biogas produced starting from day 6 of the 31-day retention period showed a specific biogas yield of 0.036 m3/kgVSadded and a methane yield of 55percent. The optimum pH maintained was 7.2 and the COD reduction achieved during the digestion period was 61percent. This simple, easy to construct, inexpensive yet efficient design will lead to improved biogas yields and quality and faster dissemination of the biogas technology.
- Full Text:
- Date Issued: 2017
- Authors: Mutungwazi Asheal
- Date: 2017
- Subjects: Sewage -- Purification -- Anaerobic treatment Green technology Renewable energy sources
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9055 , vital:34222
- Description: Biogas yield in anaerobic digesters is negatively affected by low temperatures during cold seasons and nights, temperature fluctuations and inefficient agitation. Electrical heating and underground digester installations have been used to help minimise these effects but the high cost of electrical heating, infeasibility of underground installations in some terrains, inefficient agitation and difficult maintenance continue to be major set-backs to high biogas yields. In this study a 100 ℓ, agitated, portable carbon steel digester housed within a greenhouse, whose operation temperature is automatically maintained at an optimum of 35 ± 1 oC by means of an ON/OFF electronic circuit for ventilation control through a suitably sized window and insulation offered by an air film trapped in-between a double layer of polyethylene plastic covering of the greenhouse, was designed. Cow dung from a dairy farm at the University of Fort Hare with total solids (TS), volatile solids (VS), chemical oxygen demand (COD) and ammonia nitrogen content of 162348.67 mg/ℓ, 116543.98 mg/ℓ, 37 879 mg/ℓ and 128 - 235 mg/ℓ respectively was used for the performance evaluation of the digester. Analysis of the biogas produced starting from day 6 of the 31-day retention period showed a specific biogas yield of 0.036 m3/kgVSadded and a methane yield of 55percent. The optimum pH maintained was 7.2 and the COD reduction achieved during the digestion period was 61percent. This simple, easy to construct, inexpensive yet efficient design will lead to improved biogas yields and quality and faster dissemination of the biogas technology.
- Full Text:
- Date Issued: 2017