Wavelength-modulation spectroscopy for the evaluation of the photoresponse of solar cells
- Mandanirina, Nambinintsoa Roméoh Hasinjatovo
- Authors: Mandanirina, Nambinintsoa Roméoh Hasinjatovo
- Date: 2016
- Subjects: Gallium arsenide semiconductors , Solar cells , Modulation spectroscopy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/7244 , vital:21312
- Description: This study describes the development of a wavelength-modulation spectroscopy technique for the evaluation of solar cell devices. In particular, the technique is used to investigate the sub-bandgap response associated with the incorporation of GaSb quantum rings into the active region of a conventional GaAs p-i-n solar cell. These GaSb/GaAs quantum ring solar cells are a class of third generation cells, with the potential to exceed the Shockley-Queisser efficiency limit of single junction devices. Wavelength-modulation spectroscopy (WMS) techniques involve the modulation of the wavelength of a pseudo-monochromatic light source, with the resulting variation in the measured photocurrent then being a measure of the differential optical response of the solar cell. Although the conventional photocurrent spectrum of a solar cell is a good measure of the optical response characteristics, the differential technique gives supplemental detail related to the absorption spectrum. In addition to the basic WMS setup, we also developed an in situ flux correction module to ensure that a constant excitation intensity is maintained during the wavelength modulation. The excitation source inherently has a spectral dependence that leads to an undesirable contribution to the photocurrent signal. The operation of the flux corrected WMS setup has been demonstrated by photocurrent and photo-capacitance response measurements to obtain the differential quantum efficiency and charging characteristics of the quantum ring solar cells.
- Full Text:
- Date Issued: 2016
- Authors: Mandanirina, Nambinintsoa Roméoh Hasinjatovo
- Date: 2016
- Subjects: Gallium arsenide semiconductors , Solar cells , Modulation spectroscopy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/7244 , vital:21312
- Description: This study describes the development of a wavelength-modulation spectroscopy technique for the evaluation of solar cell devices. In particular, the technique is used to investigate the sub-bandgap response associated with the incorporation of GaSb quantum rings into the active region of a conventional GaAs p-i-n solar cell. These GaSb/GaAs quantum ring solar cells are a class of third generation cells, with the potential to exceed the Shockley-Queisser efficiency limit of single junction devices. Wavelength-modulation spectroscopy (WMS) techniques involve the modulation of the wavelength of a pseudo-monochromatic light source, with the resulting variation in the measured photocurrent then being a measure of the differential optical response of the solar cell. Although the conventional photocurrent spectrum of a solar cell is a good measure of the optical response characteristics, the differential technique gives supplemental detail related to the absorption spectrum. In addition to the basic WMS setup, we also developed an in situ flux correction module to ensure that a constant excitation intensity is maintained during the wavelength modulation. The excitation source inherently has a spectral dependence that leads to an undesirable contribution to the photocurrent signal. The operation of the flux corrected WMS setup has been demonstrated by photocurrent and photo-capacitance response measurements to obtain the differential quantum efficiency and charging characteristics of the quantum ring solar cells.
- Full Text:
- Date Issued: 2016
Using data mining techniques for the prediction of student dropouts from university science programs
- Authors: Vambe, William Tichaona
- Date: 2016
- Subjects: Data mining Dropout behavior, Prediction of
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12314 , vital:39252
- Description: Data Mining has taken a center stage in education for addressing student dropout challenges as it has become one of the major threat affecting Higher Educational Institutes (HEIs). Being able to predict students who are likely to dropout helps the university to assist those facing challenges early. This will results in producing more graduates with the intellectual capital who will provide skills in the industries, hence addressing the major challenge of skill shortage being faced in South Africa. Studies and researches as purported in literature have been done to address this major threat of dropout challenge by using the theoretical approach which banked on Tinto’s model, followed by the traditional and statistical approach. However, the two lacked accuracy and the automation aspect which makes them difficult and time-consuming to use as they require to be tested periodically for them to be validated. Recently data mining has become a vital tool for predicting non-linear phenomenon including where there is missing data and bringing about accuracy and automation aspect. Data mining usefulness and reliability assessment in education made it possible to be used for prediction by different researchers. As such this research used data mining approach that integrates classification and prediction techniques to analyze student academic data at the University of Fort Hare to create a model for student dropout using preentry data and university academic performance of each student. Following Knowledge Discovery from Database (KDD) framework, data for the students enrolled in the Bachelor of Science programs between 2003 and 2014 was selected. It went through preprocessing and transformation as to deal with the missing data and noise data. Classification algorithms were then used for student characterization. Decision trees (J48) which are found in Weka software were used to build the model for data mining and prediction. The reason for choosing decision trees was it’s ability to deal with textual, nominal and numeric data as was the case with our input data and because they have good precision.The model was then trained using a train data set, validated and evaluated with another data set. Experimental results demonstrations that data mining is useful in predicting students who have chances to drop out. A critical analysis of correctly classifying instances, the confusion matrix and ROC area shows that the model can correctly classify and predict those who are likely to dropout. The model accuracy was 66percent which is a good percentage as supported in literature which means the results produced can be reliably used for assessment and make strategic decisions. Furthermore, the model took a matter of seconds to compute the results when supplied with 400 instances which prove that it is effective and efficient. Grounding our conclusion from these experimental results, this research proved that Data Mining is useful for bringing about automation, accuracy in prediction of student dropouts and the results can be reliably depended on for decision making by faculty managers who are the decision makers.
- Full Text:
- Date Issued: 2016
Using data mining techniques for the prediction of student dropouts from university science programs
- Authors: Vambe, William Tichaona
- Date: 2016
- Subjects: Data mining Dropout behavior, Prediction of
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12314 , vital:39252
- Description: Data Mining has taken a center stage in education for addressing student dropout challenges as it has become one of the major threat affecting Higher Educational Institutes (HEIs). Being able to predict students who are likely to dropout helps the university to assist those facing challenges early. This will results in producing more graduates with the intellectual capital who will provide skills in the industries, hence addressing the major challenge of skill shortage being faced in South Africa. Studies and researches as purported in literature have been done to address this major threat of dropout challenge by using the theoretical approach which banked on Tinto’s model, followed by the traditional and statistical approach. However, the two lacked accuracy and the automation aspect which makes them difficult and time-consuming to use as they require to be tested periodically for them to be validated. Recently data mining has become a vital tool for predicting non-linear phenomenon including where there is missing data and bringing about accuracy and automation aspect. Data mining usefulness and reliability assessment in education made it possible to be used for prediction by different researchers. As such this research used data mining approach that integrates classification and prediction techniques to analyze student academic data at the University of Fort Hare to create a model for student dropout using preentry data and university academic performance of each student. Following Knowledge Discovery from Database (KDD) framework, data for the students enrolled in the Bachelor of Science programs between 2003 and 2014 was selected. It went through preprocessing and transformation as to deal with the missing data and noise data. Classification algorithms were then used for student characterization. Decision trees (J48) which are found in Weka software were used to build the model for data mining and prediction. The reason for choosing decision trees was it’s ability to deal with textual, nominal and numeric data as was the case with our input data and because they have good precision.The model was then trained using a train data set, validated and evaluated with another data set. Experimental results demonstrations that data mining is useful in predicting students who have chances to drop out. A critical analysis of correctly classifying instances, the confusion matrix and ROC area shows that the model can correctly classify and predict those who are likely to dropout. The model accuracy was 66percent which is a good percentage as supported in literature which means the results produced can be reliably used for assessment and make strategic decisions. Furthermore, the model took a matter of seconds to compute the results when supplied with 400 instances which prove that it is effective and efficient. Grounding our conclusion from these experimental results, this research proved that Data Mining is useful for bringing about automation, accuracy in prediction of student dropouts and the results can be reliably depended on for decision making by faculty managers who are the decision makers.
- Full Text:
- Date Issued: 2016
Using bioinformatics tools to screen for trypanosomal cathepsin B cysteine protease inhibitors from the SANCDB as a novel therapeutic modality against Human African Trypanosomiasis (HAT)
- Authors: Mokhawa, Gaone
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3304 , vital:20470
- Description: Human African Trypanosomiasis (HAT), also known as sleeping sickness, is a fatal chronic disease that is caused by flagellated protozoans, Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense. HAT is spread by a bite from an infected tsetse fly of the Glosina genus. Up to 60 million people in 36 countries in sub-Saharan Africa are at a risk of infection from HAT with up to 30 000 deaths reported every year. Current chemotherapy for HAT is insufficient since the available drugs exhibit unacceptable side effects (toxicity) and parasite resistance. Novel treatments and approaches for development of specific and more potent drugs for HAT are therefore required. One approach is to target vital proteins that are essential to the life cycle of the parasite. The main interest of this study is to explore Trypanosoma brucei cathepsin B-like protease (TbCatB) structural and functional properties with the primary goal of discovering non peptide small molecule inhibitors of TbCatB using bioinformatics approaches. TbCatB is a papain family C1 cysteine protease which belongs to clan CA group and it has emerged as a potential HAT drug target. Papain family cysteine proteases of Clan CA group of Trypanosoma brucei (rhodesain and TbCatB) have demonstrated potential as chemotherapeutic targets using synthetic protease inhibitors like Z-Phe-Ala-CHN2 to kill the parasite in vitro and in vivo. TbCatB has been identified as the essential cysteine protease of T. brucei since mRNA silencing of TbCatB killed the parasite and resulted in a cure in mice infected with T. brucei while mRNA silencing of rhodesain only extended mice life. TbCatB is therefore a promising drug target against HAT and the discovery and development of compounds that can selectively inhibit TbCatB without posing any danger to the human host represent a great therapeutic solution for treatment of HAT. To understand protein-inhibitor interactions, useful information can be obtained from high resolution protease-inhibitor crystal structure complexes. This study aims to use bioinformatics approaches to carry out comparative sequence, structural and functional analysis of TbCatB protease and its homologs from T. congolense, T, cruzi, T. vivax and H. sapien as well as to identify non-peptide small molecule inhibitors of TbCatB cysteine proteases from natural compounds of South African origin. Sequences of TbCatB (PDB ID: 3HHI) homologs were retrieved by a BLAST search. Human cathepsin B (PDB ID: 3CBJ) was selected from a list of templates for homology modelling found by HHpred. MODELLER version 9.10 program was used to generate a hundred models for T. congolense, T, cruzi and T. vivax cathepsin B like proteases using 3HHI and 3CBJ as templates. The best models were chosen based on their low DOPE Z scores before validation using MetaMQAPII, ANOLEA, PROCHECK and QMEAN6. The DOPE Z scores and the RMSD (RMS) values of the calculated models indicate that the models are of acceptable energy (stability) and fold (conformation). Results from the different MQAPs indicate the models are of acceptable quality and they can be used for docking studies. High throughput screening of SANCDB using AutoDock Vina revealed nine compounds, SANC00 478, 479, 480, 481, 482, 488, 489, 490 and 491, having a strong affinity for Trypanosoma spp. cathepsin B proteases than HsCatB. SANC00488 has the strongest binding to Trypanosoma spp. cathepsin B proteases and the weakest binding to HsCatB protease. Molecular dynamics (MD) simulations show that the complexes between SANC00488 and TbCatB, TcCatB, TcrCatB and TvCatB are stable and do not come apart during simulation. The complex between this compound and HsCatB however is unstable and comes apart during simulation. Residues that are important for the stability of SANC00488-TbCatB complex are Gly328 of the S2 subsite, Phe208, and Ala256. In conclusion SANC00488 is a good candidate for development of a drug against HAT.
- Full Text:
- Date Issued: 2016
- Authors: Mokhawa, Gaone
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3304 , vital:20470
- Description: Human African Trypanosomiasis (HAT), also known as sleeping sickness, is a fatal chronic disease that is caused by flagellated protozoans, Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense. HAT is spread by a bite from an infected tsetse fly of the Glosina genus. Up to 60 million people in 36 countries in sub-Saharan Africa are at a risk of infection from HAT with up to 30 000 deaths reported every year. Current chemotherapy for HAT is insufficient since the available drugs exhibit unacceptable side effects (toxicity) and parasite resistance. Novel treatments and approaches for development of specific and more potent drugs for HAT are therefore required. One approach is to target vital proteins that are essential to the life cycle of the parasite. The main interest of this study is to explore Trypanosoma brucei cathepsin B-like protease (TbCatB) structural and functional properties with the primary goal of discovering non peptide small molecule inhibitors of TbCatB using bioinformatics approaches. TbCatB is a papain family C1 cysteine protease which belongs to clan CA group and it has emerged as a potential HAT drug target. Papain family cysteine proteases of Clan CA group of Trypanosoma brucei (rhodesain and TbCatB) have demonstrated potential as chemotherapeutic targets using synthetic protease inhibitors like Z-Phe-Ala-CHN2 to kill the parasite in vitro and in vivo. TbCatB has been identified as the essential cysteine protease of T. brucei since mRNA silencing of TbCatB killed the parasite and resulted in a cure in mice infected with T. brucei while mRNA silencing of rhodesain only extended mice life. TbCatB is therefore a promising drug target against HAT and the discovery and development of compounds that can selectively inhibit TbCatB without posing any danger to the human host represent a great therapeutic solution for treatment of HAT. To understand protein-inhibitor interactions, useful information can be obtained from high resolution protease-inhibitor crystal structure complexes. This study aims to use bioinformatics approaches to carry out comparative sequence, structural and functional analysis of TbCatB protease and its homologs from T. congolense, T, cruzi, T. vivax and H. sapien as well as to identify non-peptide small molecule inhibitors of TbCatB cysteine proteases from natural compounds of South African origin. Sequences of TbCatB (PDB ID: 3HHI) homologs were retrieved by a BLAST search. Human cathepsin B (PDB ID: 3CBJ) was selected from a list of templates for homology modelling found by HHpred. MODELLER version 9.10 program was used to generate a hundred models for T. congolense, T, cruzi and T. vivax cathepsin B like proteases using 3HHI and 3CBJ as templates. The best models were chosen based on their low DOPE Z scores before validation using MetaMQAPII, ANOLEA, PROCHECK and QMEAN6. The DOPE Z scores and the RMSD (RMS) values of the calculated models indicate that the models are of acceptable energy (stability) and fold (conformation). Results from the different MQAPs indicate the models are of acceptable quality and they can be used for docking studies. High throughput screening of SANCDB using AutoDock Vina revealed nine compounds, SANC00 478, 479, 480, 481, 482, 488, 489, 490 and 491, having a strong affinity for Trypanosoma spp. cathepsin B proteases than HsCatB. SANC00488 has the strongest binding to Trypanosoma spp. cathepsin B proteases and the weakest binding to HsCatB protease. Molecular dynamics (MD) simulations show that the complexes between SANC00488 and TbCatB, TcCatB, TcrCatB and TvCatB are stable and do not come apart during simulation. The complex between this compound and HsCatB however is unstable and comes apart during simulation. Residues that are important for the stability of SANC00488-TbCatB complex are Gly328 of the S2 subsite, Phe208, and Ala256. In conclusion SANC00488 is a good candidate for development of a drug against HAT.
- Full Text:
- Date Issued: 2016
Two uses of DNA sequence variation in tracing evolutionary processes in Old World primates (Primates: Catarrhini)
- Authors: Dosi, Banele
- Date: 2016
- Subjects: Primates -- Evolution Monkeys Cercopithecidae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8022 , vital:31464
- Description: Primate evolution is particularly interesting to humans, because it includes our own history. Molecular genetics is by far the most dynamic field in contemporary biology, and offers a host of new techniques for investigating evolutionary processes and patterns. In the mid-twentieth century molecular genetics evolved from being a means of visualising hidden variation (e.g. allozymes) to tracing phylogenetic relationships between and among species (evolutionary histories of populations), and now has a wide variety of applications in medicine, species identification and relationships, and even wildlife forensics. For my Master’s project I investigated two applications of molecular genetic analysis to questions regarding the evolution of Old World monkeys (Catarrhini). First, I participated in a study designed to test the hypothesis that different primate social structures – particularly mating systems – may be reflected in the structure of a species genome. We investigated whether increased sperm production as a result of sexual selection increases the number of copy number variations (CNVs) that can be detected by comparing the male specific region Y (MSY) located on the Y chromosome in a sample of primate species. We did not find a clear differentiation between the primate species as hypothesised, which thus requires a more complex explanation, e.g. in terms of the type of environment rather than the mating system of the species, or possibly the active/inactive status of the genes. The second part of my study was phylogeographic in approach. I collaborated with researchers studying the distribution of Afromontane samango monkeys (Cercopithecus albogularis labiatus) in the Eastern Cape. I sequenced tissues from 5 samango monkey specimens found opportunistically in the Hogsback and coastal forests and analysed their genetic variation relative to the data published by Dalton et al. 2015. The Hogsback sample was not monophyletic relative to the sample from the coastal forests, indicating that, on the basis of this very small sample size, these populations have not been separated historically. In order to validate this conclusion, I will need to investigate a larger sample size. From this study I developed valuable skills in the areas of the laboratory techniques involved in molecular sequence analysis, and an appreciation for the importance of large sample sizes in deriving reliable results. I intend to continue in the future with a phylogeographic study of samango monkeys.
- Full Text:
- Date Issued: 2016
- Authors: Dosi, Banele
- Date: 2016
- Subjects: Primates -- Evolution Monkeys Cercopithecidae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8022 , vital:31464
- Description: Primate evolution is particularly interesting to humans, because it includes our own history. Molecular genetics is by far the most dynamic field in contemporary biology, and offers a host of new techniques for investigating evolutionary processes and patterns. In the mid-twentieth century molecular genetics evolved from being a means of visualising hidden variation (e.g. allozymes) to tracing phylogenetic relationships between and among species (evolutionary histories of populations), and now has a wide variety of applications in medicine, species identification and relationships, and even wildlife forensics. For my Master’s project I investigated two applications of molecular genetic analysis to questions regarding the evolution of Old World monkeys (Catarrhini). First, I participated in a study designed to test the hypothesis that different primate social structures – particularly mating systems – may be reflected in the structure of a species genome. We investigated whether increased sperm production as a result of sexual selection increases the number of copy number variations (CNVs) that can be detected by comparing the male specific region Y (MSY) located on the Y chromosome in a sample of primate species. We did not find a clear differentiation between the primate species as hypothesised, which thus requires a more complex explanation, e.g. in terms of the type of environment rather than the mating system of the species, or possibly the active/inactive status of the genes. The second part of my study was phylogeographic in approach. I collaborated with researchers studying the distribution of Afromontane samango monkeys (Cercopithecus albogularis labiatus) in the Eastern Cape. I sequenced tissues from 5 samango monkey specimens found opportunistically in the Hogsback and coastal forests and analysed their genetic variation relative to the data published by Dalton et al. 2015. The Hogsback sample was not monophyletic relative to the sample from the coastal forests, indicating that, on the basis of this very small sample size, these populations have not been separated historically. In order to validate this conclusion, I will need to investigate a larger sample size. From this study I developed valuable skills in the areas of the laboratory techniques involved in molecular sequence analysis, and an appreciation for the importance of large sample sizes in deriving reliable results. I intend to continue in the future with a phylogeographic study of samango monkeys.
- Full Text:
- Date Issued: 2016
Towards determining the dietary lysine requirement in the South African abalone, Haliotis midae
- Authors: Lloyd, Kyle Everett
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/1024 , vital:20014
- Description: Animals generally do not have a requirement for protein, but instead have a requirement for specific essential amino acids (EAAs) and non-essential amino acids (NEAAs). The NEAAs are those that can be synthesised by the animal, however, EAAs cannot be synthesised and must therefore be supplied as part of the diet. When these amino acids (AAs) are supplied in the correct ratios and with the correct level of digestible energy, nutritionists can maximise somatic growth from proteins. This has resulted in increased research into the use of crystalline AAs as a tool in feed formulation research in order to quantify the AA requirements in aquaculture species, and allow for alternative protein sources (other than fishmeal) to be utilised. In common with other water soluble nutrients, leaching of crystalline AAs from diets prior to ingestion is of concern in an aquatic environment. Microencapsulation techniques have been successfully employed to restrict micronutrient leaching, and improve ingestion rates. In this research, LysiPEARL™ (Kemin®) was used as a means to determine the lysine requirement in Haliotis. midae. This encapsulated lysine product is used in the dairy cattle industry as an effective source of rumen bypass for intestinal release of lysine. It has previously been proposed that crystalline AAs are not suitable for AA studies in H. midae due to the slow feeding rates of the species as well as the solubility of these AAs. However, 90.00 % of supplemented lysine was maintained in this study after a six hour period of leaching, showing that if effective microencapsulation techniques are used, it is possible to use crystalline amino acids to supplement protein bound lysine in abalone feeds. Six isoenergetic (15.90 MJ/kg), isolipidic (6.00 %) and isonitrogenous (29.00 %) diets enriched with 5.52, 6.40, 7.28, 8.14, 9.00 and 9.86 % lysine (as a % of protein) were fed to triplicate groups of 20 H. midae (20.41 ± 1.95 mm SL 1.51 ± 0.44 g w.wt) for 90 days. Wet weight and shell length measurements were taken every 30 days and specific growth rate (SGR) (% body weight.day-1), feed conversion ratio (FCR), protein efficiency ratio (PER), feed consumption (% body weight.day-1) and condition factor were calculated for each dietary treatment. Linear regression showed that FCR increased as dietary lysine increased (Regression analysis, p=0.031), and that PER reduced as dietary lysine increased (Regression analysis, p=0.026). Feed consumption also increased as dietary lysine increased (Regression analysis, p<0.001). The inclusion of lysine at 7.28 % of the total protein in the diet resulted in significantly superior SGR (0.57±0.01 % body weight.day-1) to that of 5.52 % (0.42±0.05 % body weight.day-1), FCR (1.51±0.05) to that of 8.14 % (1.99±0.21) and PER (2.45±0.07) to that of 8.14 % (1.99±0.18; ANOVA, p<0.05). There was a significant difference found in feed consumption (% body wt.d-1), with consumption increasing significantly between the first three dietary treatments and the last three dietary treatments (ANOVA, p<0.001). There was no significant improvement in SGR when dietary lysine increased above 7.28 % of the dietary protein in the diet, indicating that dietary lysine requirement was being met at 7.28 %, after which excess lysine promoted no growth response. The diet producing the best SGR, PER and FCR in this study was diet 3 which had a measured lysine content of 6.90 %. The results of the present study suggest that the lysine requirement in H. midae is in the range of 6.00 - 7.00 % of dietary protein. From these data amino acid ratios were used to estimate optimum inclusion levels of other essential amino acids. However, lysine availability in LysiPEARL™ may have resulted in over estimations due to the lipid encapsulation technique used, and haliotids limited ability to efficiently digest lipids. For this reason EAA requirements were suggested based on three different hypothetical scenarios of lysine availability from LysiPEARL™.
- Full Text:
- Date Issued: 2016
- Authors: Lloyd, Kyle Everett
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/1024 , vital:20014
- Description: Animals generally do not have a requirement for protein, but instead have a requirement for specific essential amino acids (EAAs) and non-essential amino acids (NEAAs). The NEAAs are those that can be synthesised by the animal, however, EAAs cannot be synthesised and must therefore be supplied as part of the diet. When these amino acids (AAs) are supplied in the correct ratios and with the correct level of digestible energy, nutritionists can maximise somatic growth from proteins. This has resulted in increased research into the use of crystalline AAs as a tool in feed formulation research in order to quantify the AA requirements in aquaculture species, and allow for alternative protein sources (other than fishmeal) to be utilised. In common with other water soluble nutrients, leaching of crystalline AAs from diets prior to ingestion is of concern in an aquatic environment. Microencapsulation techniques have been successfully employed to restrict micronutrient leaching, and improve ingestion rates. In this research, LysiPEARL™ (Kemin®) was used as a means to determine the lysine requirement in Haliotis. midae. This encapsulated lysine product is used in the dairy cattle industry as an effective source of rumen bypass for intestinal release of lysine. It has previously been proposed that crystalline AAs are not suitable for AA studies in H. midae due to the slow feeding rates of the species as well as the solubility of these AAs. However, 90.00 % of supplemented lysine was maintained in this study after a six hour period of leaching, showing that if effective microencapsulation techniques are used, it is possible to use crystalline amino acids to supplement protein bound lysine in abalone feeds. Six isoenergetic (15.90 MJ/kg), isolipidic (6.00 %) and isonitrogenous (29.00 %) diets enriched with 5.52, 6.40, 7.28, 8.14, 9.00 and 9.86 % lysine (as a % of protein) were fed to triplicate groups of 20 H. midae (20.41 ± 1.95 mm SL 1.51 ± 0.44 g w.wt) for 90 days. Wet weight and shell length measurements were taken every 30 days and specific growth rate (SGR) (% body weight.day-1), feed conversion ratio (FCR), protein efficiency ratio (PER), feed consumption (% body weight.day-1) and condition factor were calculated for each dietary treatment. Linear regression showed that FCR increased as dietary lysine increased (Regression analysis, p=0.031), and that PER reduced as dietary lysine increased (Regression analysis, p=0.026). Feed consumption also increased as dietary lysine increased (Regression analysis, p<0.001). The inclusion of lysine at 7.28 % of the total protein in the diet resulted in significantly superior SGR (0.57±0.01 % body weight.day-1) to that of 5.52 % (0.42±0.05 % body weight.day-1), FCR (1.51±0.05) to that of 8.14 % (1.99±0.21) and PER (2.45±0.07) to that of 8.14 % (1.99±0.18; ANOVA, p<0.05). There was a significant difference found in feed consumption (% body wt.d-1), with consumption increasing significantly between the first three dietary treatments and the last three dietary treatments (ANOVA, p<0.001). There was no significant improvement in SGR when dietary lysine increased above 7.28 % of the dietary protein in the diet, indicating that dietary lysine requirement was being met at 7.28 %, after which excess lysine promoted no growth response. The diet producing the best SGR, PER and FCR in this study was diet 3 which had a measured lysine content of 6.90 %. The results of the present study suggest that the lysine requirement in H. midae is in the range of 6.00 - 7.00 % of dietary protein. From these data amino acid ratios were used to estimate optimum inclusion levels of other essential amino acids. However, lysine availability in LysiPEARL™ may have resulted in over estimations due to the lipid encapsulation technique used, and haliotids limited ability to efficiently digest lipids. For this reason EAA requirements were suggested based on three different hypothetical scenarios of lysine availability from LysiPEARL™.
- Full Text:
- Date Issued: 2016
Towards an industrial ecology for the Nelson Mandela Bay: Metropolitan area
- Authors: Dalindyebo, Litha
- Date: 2016
- Subjects: Industrial ecology -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/9263 , vital:26556
- Description: The aim of this study is to formulate a model of industrial ecology for wider application in the Nelson Mandel Bay (NMB) Metropole. To achieve this aim, the following objectives will be pursued: • A theoretical investigation of the concept of industrial ecology – in an attempt to establish its meaning, as well as the implications thereof. • A theoretical investigation of the operational implications of industrial ecology, including existing methodologies, such as Material Flow Analysis (MFA) and Life Cycle Assessment (LCA) that can be applied, in order to develop a system of industrial ecology between different companies. • The formulation of a methodology for application to the case study. • Presenting and discussing the research results produced by the application of the industrial ecology related methodology to the case study. • To present a synthesis of the research results of this study. This objective includes a critical evaluation of the research methodology and results, as well as some recommendations for the facilitation of industrial ecology. The methodology of the research involved conducting semi structured interviews, conducting a Material Flow Analysis and Life Cycle Analysis using SIMAPRO software. There interview with Goodyear management took place (see Appendix A), while the management at Sovereign Foods agreed to an interview however they didn’t honour the agreement. During the interview at Goodyear understanding of the operational process was achieved by conducting the interviews. The three areas that were discussed during the interview process were: 1. How the boiler works; 2. Current Air-Emission results; and 3. The process of steam generation. An MFA and an LCA on the production process of comparing the boiler functionality was conducted, so that there is an adequate understanding of the environmental performance of the two different boilers. The results of the MFA are presented as follows, namely: the goal and scope definition and the inventory results. Coal boiler versus fluidised boiler data where modelled. The modelling is done on comparing the flow of chemicals during steam production process, and which chemicals have a significant environmental impact. The LCA results looked at the basis of the symbiotic approach by identifying sustainable choices of design, production and consumption. The findings of this research have been obtained from the investigation of industrial ecology framework planning at Goodyear SA and Sovereign Foods. The findings have revealed that there is a synergy that exists between the two case-study areas. However, this is based on Goodyear changing the technology of the boiler they use (a boiler creates steam for the tyre-building process). The company will be required to use a fluidised boiler, instead of the current coal boiler. The use of the fluidised boiler will ensure that all waste streams at Goodyear will be reused and recycled, thereby creating the framework for industrial ecology. The results that are firstly drawn out of SIMAPRO is the Life Cycle Inventory. In this research, there is a flow of 1437 chemical materials and substances in the production of steam using both coal boiler and fluidized boiler. Due to the number of substance flow elements, the research has presented only the significant substances that influence the environmental performance of steam production using the two different feeder materials, which are coal and chicken matter (see Figure 4.4). In the coal boiler process, sulfur comprises the largest amount of chemical substance. The other top five chemical components that contribute to the steam production process are: nickel, chromium, arsenic and iodosulfuron-methyl-sodium. The scale of figure 4.4 is reduced to show the various number of chemical flows found in the steam production process through SIMAPRO software. The Life Cycle Assessment (LCA) results were presented looking at namely the following characterization, normalization, weighting, single score and damage assessment (see Figure 4.7 – 4.10 p87 – p90). The figures are presented as taken directly from the reports drawn from the SIMAPRO software. Figure 4.7 gives the characterisation results up to 100%, where 0% has a minimal environmental effect; whereas 100% has the most significant environmental effect. Oxidation of coal is compared versus the oxidation of chicken matter, the coal boiler process has higher environmental impacts. Figure 4.8 shows the normalisation results of the coal boiler versus the fluidised boiler for the functional unit steam production. The environmental degradation under normalisation between the two boilers are measured, based on three parameters, namely: human health, ecosystems and resources. In all three parameters that are measured under normalisation, the production of steam using the coal boiler has the highest impacts. The weighting results in Figure 4.9 show a mirror image of the normalisation results. Finally, a gap analysis of the theoretical requirements for industrial ecology is displayed versus what currently exists in the case study area. The gap analysis will assist in the development of recommendations. These will be presented in the next chapter. A gap analysis of findings is discussed leading into the synthesis. The value of this research is that the baseline data of planning for an industrial ecology create a platform that can be used for implementing an industrial ecology between Goodyear SA and Sovereign Foods. This will, in time, have wider applications for the entire NMB metropole.
- Full Text:
- Date Issued: 2016
- Authors: Dalindyebo, Litha
- Date: 2016
- Subjects: Industrial ecology -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/9263 , vital:26556
- Description: The aim of this study is to formulate a model of industrial ecology for wider application in the Nelson Mandel Bay (NMB) Metropole. To achieve this aim, the following objectives will be pursued: • A theoretical investigation of the concept of industrial ecology – in an attempt to establish its meaning, as well as the implications thereof. • A theoretical investigation of the operational implications of industrial ecology, including existing methodologies, such as Material Flow Analysis (MFA) and Life Cycle Assessment (LCA) that can be applied, in order to develop a system of industrial ecology between different companies. • The formulation of a methodology for application to the case study. • Presenting and discussing the research results produced by the application of the industrial ecology related methodology to the case study. • To present a synthesis of the research results of this study. This objective includes a critical evaluation of the research methodology and results, as well as some recommendations for the facilitation of industrial ecology. The methodology of the research involved conducting semi structured interviews, conducting a Material Flow Analysis and Life Cycle Analysis using SIMAPRO software. There interview with Goodyear management took place (see Appendix A), while the management at Sovereign Foods agreed to an interview however they didn’t honour the agreement. During the interview at Goodyear understanding of the operational process was achieved by conducting the interviews. The three areas that were discussed during the interview process were: 1. How the boiler works; 2. Current Air-Emission results; and 3. The process of steam generation. An MFA and an LCA on the production process of comparing the boiler functionality was conducted, so that there is an adequate understanding of the environmental performance of the two different boilers. The results of the MFA are presented as follows, namely: the goal and scope definition and the inventory results. Coal boiler versus fluidised boiler data where modelled. The modelling is done on comparing the flow of chemicals during steam production process, and which chemicals have a significant environmental impact. The LCA results looked at the basis of the symbiotic approach by identifying sustainable choices of design, production and consumption. The findings of this research have been obtained from the investigation of industrial ecology framework planning at Goodyear SA and Sovereign Foods. The findings have revealed that there is a synergy that exists between the two case-study areas. However, this is based on Goodyear changing the technology of the boiler they use (a boiler creates steam for the tyre-building process). The company will be required to use a fluidised boiler, instead of the current coal boiler. The use of the fluidised boiler will ensure that all waste streams at Goodyear will be reused and recycled, thereby creating the framework for industrial ecology. The results that are firstly drawn out of SIMAPRO is the Life Cycle Inventory. In this research, there is a flow of 1437 chemical materials and substances in the production of steam using both coal boiler and fluidized boiler. Due to the number of substance flow elements, the research has presented only the significant substances that influence the environmental performance of steam production using the two different feeder materials, which are coal and chicken matter (see Figure 4.4). In the coal boiler process, sulfur comprises the largest amount of chemical substance. The other top five chemical components that contribute to the steam production process are: nickel, chromium, arsenic and iodosulfuron-methyl-sodium. The scale of figure 4.4 is reduced to show the various number of chemical flows found in the steam production process through SIMAPRO software. The Life Cycle Assessment (LCA) results were presented looking at namely the following characterization, normalization, weighting, single score and damage assessment (see Figure 4.7 – 4.10 p87 – p90). The figures are presented as taken directly from the reports drawn from the SIMAPRO software. Figure 4.7 gives the characterisation results up to 100%, where 0% has a minimal environmental effect; whereas 100% has the most significant environmental effect. Oxidation of coal is compared versus the oxidation of chicken matter, the coal boiler process has higher environmental impacts. Figure 4.8 shows the normalisation results of the coal boiler versus the fluidised boiler for the functional unit steam production. The environmental degradation under normalisation between the two boilers are measured, based on three parameters, namely: human health, ecosystems and resources. In all three parameters that are measured under normalisation, the production of steam using the coal boiler has the highest impacts. The weighting results in Figure 4.9 show a mirror image of the normalisation results. Finally, a gap analysis of the theoretical requirements for industrial ecology is displayed versus what currently exists in the case study area. The gap analysis will assist in the development of recommendations. These will be presented in the next chapter. A gap analysis of findings is discussed leading into the synthesis. The value of this research is that the baseline data of planning for an industrial ecology create a platform that can be used for implementing an industrial ecology between Goodyear SA and Sovereign Foods. This will, in time, have wider applications for the entire NMB metropole.
- Full Text:
- Date Issued: 2016
Towards an alternative spatial-based management approach for estuarine fisheries in South Africa, with a case study from the Sundays Estuary
- Authors: Kramer, Rachel
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/1007 , vital:20012
- Description: Estuaries are productive habitats and biologically important ecosystems which serve as juvenile nursery areas and feeding grounds for adults from a host of fish species. They are, however, threatened habitats, increasingly exposed to human disturbance and exploitation. The stocks of several South African estuary-dependent linefish species are now considered as either overexploited or collapsed. It is clear that their dependence on estuaries would warrant the inclusion of these ecosystems into marine reserve planning exercises. Since traditional management strategies (e.g. bag and size limit restrictions) have proven ineffective for estuarine fisheries, there is a need for alternative management measures, such as spatial and temporal restrictions, to ensure increased survival of juveniles and recovery of adult breeding populations. This thesis explored the potential for an ecosystem-based approach through the application of a rapid sustainability assessment technique, and a spatial-based management approach for an important fishery species, using conservation planning software. The Sundays Estuary, Eastern Cape, South Africa falls within the footprint of the Addo Elephant National Park, with a proposed expansion to include a marine protected area (MPA). However the estuaries resources were not considered during the planning of the proposed MPA. This study conducted an indicator-based sustainability assessment based on the principles of sustainable development. The results showed that present levels of exploitation, due to non-compliance and a lack of law enforcement are unsustainable. The sustainability of the Sundays Estuary had a low overall sustainability score of only 23.8%. With limited enforcement of estuarine fisheries regulations in South Africa, alternative management measures such as spatial regulations may provide a viable option forward. The sustainability of fishery resources depends on the comprehensive understanding of the fishery resource. Acoustic telemetry is a technique that has been widely adopted to infer habitat and area use patterns of fish species. The second component of this study made use of high resolution telemetry data collected on juvenile dusky kob Argyrosomus japonicus movements within the Sundays Estuary to conduct a scenario-based approach using Marxan conservation planning software. The best solution given by Marxan, in the form of a protected area for the conservation of juvenile A. japonicus in the Sundays Estuary was identified in the middle (starting 7km from the mouth) to the upper reaches (approximately 16km from the mouth) of the estuary, ultimately providing protection to tagged individuals for 61% of their time in the estuary. Although Marxan presented a best solution, the Sundays Estuary’s small size and shape, and minimal features used, was too simplistic to be included into a Marxan analysis. However, new methods and tools to analyse and plan spatial-based management options at this scale are currently being developed. Using the Sundays Estuary as a case study, a decision tree was then developed as a protocol to assist management address the challenges of effective estuarine management depending on the unique biological and socio-economic characteristics of individual estuaries in South Africa.
- Full Text:
- Date Issued: 2016
- Authors: Kramer, Rachel
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/1007 , vital:20012
- Description: Estuaries are productive habitats and biologically important ecosystems which serve as juvenile nursery areas and feeding grounds for adults from a host of fish species. They are, however, threatened habitats, increasingly exposed to human disturbance and exploitation. The stocks of several South African estuary-dependent linefish species are now considered as either overexploited or collapsed. It is clear that their dependence on estuaries would warrant the inclusion of these ecosystems into marine reserve planning exercises. Since traditional management strategies (e.g. bag and size limit restrictions) have proven ineffective for estuarine fisheries, there is a need for alternative management measures, such as spatial and temporal restrictions, to ensure increased survival of juveniles and recovery of adult breeding populations. This thesis explored the potential for an ecosystem-based approach through the application of a rapid sustainability assessment technique, and a spatial-based management approach for an important fishery species, using conservation planning software. The Sundays Estuary, Eastern Cape, South Africa falls within the footprint of the Addo Elephant National Park, with a proposed expansion to include a marine protected area (MPA). However the estuaries resources were not considered during the planning of the proposed MPA. This study conducted an indicator-based sustainability assessment based on the principles of sustainable development. The results showed that present levels of exploitation, due to non-compliance and a lack of law enforcement are unsustainable. The sustainability of the Sundays Estuary had a low overall sustainability score of only 23.8%. With limited enforcement of estuarine fisheries regulations in South Africa, alternative management measures such as spatial regulations may provide a viable option forward. The sustainability of fishery resources depends on the comprehensive understanding of the fishery resource. Acoustic telemetry is a technique that has been widely adopted to infer habitat and area use patterns of fish species. The second component of this study made use of high resolution telemetry data collected on juvenile dusky kob Argyrosomus japonicus movements within the Sundays Estuary to conduct a scenario-based approach using Marxan conservation planning software. The best solution given by Marxan, in the form of a protected area for the conservation of juvenile A. japonicus in the Sundays Estuary was identified in the middle (starting 7km from the mouth) to the upper reaches (approximately 16km from the mouth) of the estuary, ultimately providing protection to tagged individuals for 61% of their time in the estuary. Although Marxan presented a best solution, the Sundays Estuary’s small size and shape, and minimal features used, was too simplistic to be included into a Marxan analysis. However, new methods and tools to analyse and plan spatial-based management options at this scale are currently being developed. Using the Sundays Estuary as a case study, a decision tree was then developed as a protocol to assist management address the challenges of effective estuarine management depending on the unique biological and socio-economic characteristics of individual estuaries in South Africa.
- Full Text:
- Date Issued: 2016
Toward an automated botnet analysis framework: a darkcomet case-study
- Authors: du Bruyn, Jeremy Cecil
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2937 , vital:20344
- Full Text:
- Date Issued: 2016
- Authors: du Bruyn, Jeremy Cecil
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2937 , vital:20344
- Full Text:
- Date Issued: 2016
Thermoluminescence of annealed synthetic quartz
- Atang, Elizabeth Fende Midiki
- Authors: Atang, Elizabeth Fende Midiki
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/420 , vital:19957
- Description: The kinetic and dosimetric features of the main thermoluminescent peak of synthetic quartz have been investigated in quartz ordinarily annealed at 500_C as well as quartz annealed at 500_C for 10 minutes. The main peak is found at 78 _C for the samples annealed at 500_C for 10 minutes irradiated to 10 Gy and heated at 1.0 _C/s. For the samples ordinarily annealed at 500_C the main peak is found at 106 _C after the sample has been irradiated to 30 Gy and heated at 5.0 _C/s. In these samples, the intensity of the main peak is enhanced with repetitive measurement whereas its maximum temperature is unaffected. The peak position of the main peak in the sample is independent of the irradiation dose and this, together with its fading characteristics, are consistent with first-order kinetics. For doses between 5 and 25 Gy, the dose response of the main peak of the annealed sample is superlinear. The half-life of the main TL peak of the annealed sample is about 1 h. The activation energy E of the main peak is around 0.90 eV. For a heating rate of 0.4 _C/s, its order of kinetics b derived from the whole curve method of analysis is 1.0. Following irradiation, preheating and illumination with 470 nm blue light, the main peak in the annealed sample is regenerated during heating. The resulting phototransferred peak occurs at the same temperature as the original peak and has similar kinetic and dosimetric features, with a half-life of about 1 h. For a preheat temperature of 200 _C, the intensity of the phototransferred peak in the sample increases with illumination time up to a maximum and decreases thereafter. At longer illumination times, no further decrease in the intensity of the phototransferred peak is observed. The traps associated with the 325 _C peak are the main source of the electrons responsible for the regenerated peak.
- Full Text:
- Date Issued: 2016
- Authors: Atang, Elizabeth Fende Midiki
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/420 , vital:19957
- Description: The kinetic and dosimetric features of the main thermoluminescent peak of synthetic quartz have been investigated in quartz ordinarily annealed at 500_C as well as quartz annealed at 500_C for 10 minutes. The main peak is found at 78 _C for the samples annealed at 500_C for 10 minutes irradiated to 10 Gy and heated at 1.0 _C/s. For the samples ordinarily annealed at 500_C the main peak is found at 106 _C after the sample has been irradiated to 30 Gy and heated at 5.0 _C/s. In these samples, the intensity of the main peak is enhanced with repetitive measurement whereas its maximum temperature is unaffected. The peak position of the main peak in the sample is independent of the irradiation dose and this, together with its fading characteristics, are consistent with first-order kinetics. For doses between 5 and 25 Gy, the dose response of the main peak of the annealed sample is superlinear. The half-life of the main TL peak of the annealed sample is about 1 h. The activation energy E of the main peak is around 0.90 eV. For a heating rate of 0.4 _C/s, its order of kinetics b derived from the whole curve method of analysis is 1.0. Following irradiation, preheating and illumination with 470 nm blue light, the main peak in the annealed sample is regenerated during heating. The resulting phototransferred peak occurs at the same temperature as the original peak and has similar kinetic and dosimetric features, with a half-life of about 1 h. For a preheat temperature of 200 _C, the intensity of the phototransferred peak in the sample increases with illumination time up to a maximum and decreases thereafter. At longer illumination times, no further decrease in the intensity of the phototransferred peak is observed. The traps associated with the 325 _C peak are the main source of the electrons responsible for the regenerated peak.
- Full Text:
- Date Issued: 2016
The use of treated brewery effluent as a water and nutrient source in crop irrigation
- Authors: Taylor, Richard Peter
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5390 , http://hdl.handle.net/10962/d1021265
- Description: Brewery effluent (BE) needs to be treated before it can be released into the environment, reused or used in down-stream activities. Current technologies used to address this concern at the experimental wastewater treatment plant at Ibahyi Brewery (SAB Ltd) include anaerobic digestion (AD), primary facultative ponds (PFP), high rate algal ponds (HRAP) and constructed wetlands (CW). The aim of this work was to determine if BE treated in these systems might be suitable for crop irrigation. A test crop, cabbage (Brassica oleracea cv. Star 3301), grew best on post-AD and post-PFP BE compared to those irrigated with post-HRAP or post-CW effluent. However, the yield was 13% lower than cabbage plants irrigated with a commercial nutrient solution and fresh water. The relatively high conductivity (3019.05 ± 48.72 μs/cm2) of BE may be the main factor reducing the cabbage yields. Post-HRAP and post-CW BE were the least suitable for irrigated crop production due to the higher conductivity and lower nutrient content of these treated effluents. After three months, soils irrigated with post-AD and post-PFP BE had a significantly higher sodium content and sodium adsorption ratio (3919 ± 94.77 mg/kg & 8.18 ± 0.17) than soil irrigated with a commercial nutrient solution (920.58 ± 27.46 mg/kg & 2.20 ± 0.05; p<0.05). However, this was not accompanied by a deterioration in the soil’s hydro-physical properties, nor a change in the metabolic community structure of the soil (p>0.05). After prolonged irrigation with treated BE, sodium is likely to build up in the soil and this can be expected to be accompanied by a deterioration in the soil physical structure. However, crops species such as millet (Echinochloa esculenta), lucerne (Medicago sativa) and saltbush (Atriplex nummularia) reduced the build-up of sodium in the soil. The results suggest that sodium was mainly removed from the soil through plant-assisted leaching. Of the crops grown, lucerne showed the most promise because it improved the soil physical properties, is able to grow well in alkaline environments, is a popular fodder crop and can be harvested multiple times from a single stand. Brewery effluent is more suitable for soil production systems than hydroponic production systems because the soil was able to act as a buffer against the high pH of post-AD BE, whereas in a hydroponics systems the high pH reduced the availability of key minerals to plants. In conclusion brewery effluent contains sufficient plants nutrients to support the growth of cabbages, saltbush, lucerne and millet. However the sodium content of BE is a concern as it accumulates in the soil, and in the long-term it may lead to soil degradation. It is suggested that the brewery change the pH neutralising treatment of BE from sodium hydroxide to potassium hydroxide, or dolomitic lime (calcium and magnesium carbonate) because this would reduce the introduction of sodium into the system, and would increase the suitability of BE for crop production, given potassium and calcium are plant nutrients. The benefits of developing this nutrient and water resource could contribute to cost-reductions at the brewery, more efficient water, nutrient and energy management, create job opportunities with the potential of improving food security in the local community.
- Full Text:
- Date Issued: 2016
- Authors: Taylor, Richard Peter
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5390 , http://hdl.handle.net/10962/d1021265
- Description: Brewery effluent (BE) needs to be treated before it can be released into the environment, reused or used in down-stream activities. Current technologies used to address this concern at the experimental wastewater treatment plant at Ibahyi Brewery (SAB Ltd) include anaerobic digestion (AD), primary facultative ponds (PFP), high rate algal ponds (HRAP) and constructed wetlands (CW). The aim of this work was to determine if BE treated in these systems might be suitable for crop irrigation. A test crop, cabbage (Brassica oleracea cv. Star 3301), grew best on post-AD and post-PFP BE compared to those irrigated with post-HRAP or post-CW effluent. However, the yield was 13% lower than cabbage plants irrigated with a commercial nutrient solution and fresh water. The relatively high conductivity (3019.05 ± 48.72 μs/cm2) of BE may be the main factor reducing the cabbage yields. Post-HRAP and post-CW BE were the least suitable for irrigated crop production due to the higher conductivity and lower nutrient content of these treated effluents. After three months, soils irrigated with post-AD and post-PFP BE had a significantly higher sodium content and sodium adsorption ratio (3919 ± 94.77 mg/kg & 8.18 ± 0.17) than soil irrigated with a commercial nutrient solution (920.58 ± 27.46 mg/kg & 2.20 ± 0.05; p<0.05). However, this was not accompanied by a deterioration in the soil’s hydro-physical properties, nor a change in the metabolic community structure of the soil (p>0.05). After prolonged irrigation with treated BE, sodium is likely to build up in the soil and this can be expected to be accompanied by a deterioration in the soil physical structure. However, crops species such as millet (Echinochloa esculenta), lucerne (Medicago sativa) and saltbush (Atriplex nummularia) reduced the build-up of sodium in the soil. The results suggest that sodium was mainly removed from the soil through plant-assisted leaching. Of the crops grown, lucerne showed the most promise because it improved the soil physical properties, is able to grow well in alkaline environments, is a popular fodder crop and can be harvested multiple times from a single stand. Brewery effluent is more suitable for soil production systems than hydroponic production systems because the soil was able to act as a buffer against the high pH of post-AD BE, whereas in a hydroponics systems the high pH reduced the availability of key minerals to plants. In conclusion brewery effluent contains sufficient plants nutrients to support the growth of cabbages, saltbush, lucerne and millet. However the sodium content of BE is a concern as it accumulates in the soil, and in the long-term it may lead to soil degradation. It is suggested that the brewery change the pH neutralising treatment of BE from sodium hydroxide to potassium hydroxide, or dolomitic lime (calcium and magnesium carbonate) because this would reduce the introduction of sodium into the system, and would increase the suitability of BE for crop production, given potassium and calcium are plant nutrients. The benefits of developing this nutrient and water resource could contribute to cost-reductions at the brewery, more efficient water, nutrient and energy management, create job opportunities with the potential of improving food security in the local community.
- Full Text:
- Date Issued: 2016
The trophic and spatial ecology of juvenile porcupine rays Urogymnus asperrimus at the remote St. Joseph Atoll
- Authors: Elston, Chantel
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/965 , vital:20007
- Description: Little information exists for the widely occurring but rare porcupine ray Urogymnus asperrimus. This is a concern given that it is a vulnerable species and likely plays an important ecological role in tropical atoll ecosystems. The aims of this thesis were to investigate the trophic and spatial ecology of juvenile porcupine rays within the St. Joseph Atoll, which is hypothesized to be functioning as a nursery for this species. Specific objectives were to determine i) the dietary composition and resource selectivity displayed by juvenile porcupine rays, ii) residency to the atoll, space use, and seasonality in movements, and iii) whether environmental factors affect short-term movements. Gastric lavage was used to collect stomach contents from 55 juveniles and sediment samples were collected. Thirteen juveniles were implanted with acoustic transmitters and monitored for a year by an array of 88 acoustic receivers situated in and around the St. Joseph Atoll. Porcupine rays appeared to be generalist and opportunistic feeders, foraging predominantly on annelids with the highest environmental availability. Polychaetes of the family Capitellidae were the most important prey item (Index of Importance = 35%). Rays only fed on deep infaunal prey, likely because of their foraging behaviour, suggesting they may influence this community. There was a size-related shift in the crustacean families consumed. The tagged rays displayed high residency to the atoll (mean residency index of 64%) and restricted movements, with small core use and activity space areas (mean of 0.5km² and 3km² respectively) and the majority of detections were recorded within 1km of their tagging locations. The rays favoured the sand ats where 88% of detections occurred. Transient use of the lagoon and fringe reef peaked in the north-west monsoon season, indicating a seasonal usage of these habitats. The effects of temperature and water depth on movements were manifested as diel and tidal cyclical patterns in presence. Evidence illustrates that the St. Joseph Atoll constitutes an important nursery for this species, which has been declared a Marine Protected Area. A major determinant behind the dependence of this nursery habitat is related to predator avoidance. Thermoregulatory behaviours were identified, suggesting that this species is vulnerable to climate change.
- Full Text:
- Date Issued: 2016
- Authors: Elston, Chantel
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/965 , vital:20007
- Description: Little information exists for the widely occurring but rare porcupine ray Urogymnus asperrimus. This is a concern given that it is a vulnerable species and likely plays an important ecological role in tropical atoll ecosystems. The aims of this thesis were to investigate the trophic and spatial ecology of juvenile porcupine rays within the St. Joseph Atoll, which is hypothesized to be functioning as a nursery for this species. Specific objectives were to determine i) the dietary composition and resource selectivity displayed by juvenile porcupine rays, ii) residency to the atoll, space use, and seasonality in movements, and iii) whether environmental factors affect short-term movements. Gastric lavage was used to collect stomach contents from 55 juveniles and sediment samples were collected. Thirteen juveniles were implanted with acoustic transmitters and monitored for a year by an array of 88 acoustic receivers situated in and around the St. Joseph Atoll. Porcupine rays appeared to be generalist and opportunistic feeders, foraging predominantly on annelids with the highest environmental availability. Polychaetes of the family Capitellidae were the most important prey item (Index of Importance = 35%). Rays only fed on deep infaunal prey, likely because of their foraging behaviour, suggesting they may influence this community. There was a size-related shift in the crustacean families consumed. The tagged rays displayed high residency to the atoll (mean residency index of 64%) and restricted movements, with small core use and activity space areas (mean of 0.5km² and 3km² respectively) and the majority of detections were recorded within 1km of their tagging locations. The rays favoured the sand ats where 88% of detections occurred. Transient use of the lagoon and fringe reef peaked in the north-west monsoon season, indicating a seasonal usage of these habitats. The effects of temperature and water depth on movements were manifested as diel and tidal cyclical patterns in presence. Evidence illustrates that the St. Joseph Atoll constitutes an important nursery for this species, which has been declared a Marine Protected Area. A major determinant behind the dependence of this nursery habitat is related to predator avoidance. Thermoregulatory behaviours were identified, suggesting that this species is vulnerable to climate change.
- Full Text:
- Date Issued: 2016
The role of cancer procoagulant on the MTOR pathway
- Authors: Chiuswa, Chengetanai
- Date: 2016
- Subjects: Cancer -- Research , Neovascularization , Biochemistry , Blood coagulation factors -- Biotechnology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/7303 , vital:21316
- Description: Cancer procoagulant (CP) is a cysteine protease found in tumour cells and amnion chorion membranes. The main function of CP is not yet known, but it has potential roles in tumour growth and metastasis. Initially, CP was believed to increase coagulation in cancer patients; however, research has shown that increase in CP concentration does not correlate with an increase in coagulation. The location of CP in amnion chorion membranes and tumour cells only led to the hypothesis that CP might be involved in inducing blood vessel and or lymph vessel formation. CP was shown to induce lymphangiogenesis (lymph vessel formation) in human telomerase reverse transcriptase-human dermal endothelial cells (hTERT-HDLEC) (Tshaka, 2011). CP-induced tube formation was inhibited by rapamycin; indicating that CP may be signalling via the mammalian target of rapamycin (mTOR) pathway. The aim of this study was to investigate the effect of CP on the mTOR signalling pathway using human umbilical endothelial vein cells (HUVECs) as a model. CP was isolated from amnion chorion membranes and purified using two anion exchange chromatography steps. Purified CP (2 μg/ml) was used to induce tube formation in endothelial cells (HUVECs) seeded on growth factor reduced (GFR) Matrigel. In addition, the 2 μg/ml CP was used to treat cultured HUVECs. Sodium dodecyl sulphate polyacrylamide electrophoresis (SDS-PAGE) and western blotting were used to determine phosphorylation levels of protein kinase B (Akt) and ribosomal protein S6 kinase (S6K). CP was successfully isolated and purified using anion exchange chromatography. The effect of CP on tube formation was not significant relative to the control in the HUVEC cell line. The role of CP on Akt and S6K phosphorylation still needs to be verified by using sensitive methods of quantification such as enhanced chemiluminescence (ECL) and enzyme linked immunosorbent assay (ELISA). The levels of CP activity were shown to be higher in early tumour growth than in advanced cancer suggesting that certain physiological factors could be increasing CP activity during early tumour growth. This study investigated the effect of cobalt chloride on CP activity in breast cancer cell lines. Cobalt chloride reduced CP activity in MCF-7 and promoted CP activity in MDA-MB-231.
- Full Text:
- Date Issued: 2016
- Authors: Chiuswa, Chengetanai
- Date: 2016
- Subjects: Cancer -- Research , Neovascularization , Biochemistry , Blood coagulation factors -- Biotechnology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/7303 , vital:21316
- Description: Cancer procoagulant (CP) is a cysteine protease found in tumour cells and amnion chorion membranes. The main function of CP is not yet known, but it has potential roles in tumour growth and metastasis. Initially, CP was believed to increase coagulation in cancer patients; however, research has shown that increase in CP concentration does not correlate with an increase in coagulation. The location of CP in amnion chorion membranes and tumour cells only led to the hypothesis that CP might be involved in inducing blood vessel and or lymph vessel formation. CP was shown to induce lymphangiogenesis (lymph vessel formation) in human telomerase reverse transcriptase-human dermal endothelial cells (hTERT-HDLEC) (Tshaka, 2011). CP-induced tube formation was inhibited by rapamycin; indicating that CP may be signalling via the mammalian target of rapamycin (mTOR) pathway. The aim of this study was to investigate the effect of CP on the mTOR signalling pathway using human umbilical endothelial vein cells (HUVECs) as a model. CP was isolated from amnion chorion membranes and purified using two anion exchange chromatography steps. Purified CP (2 μg/ml) was used to induce tube formation in endothelial cells (HUVECs) seeded on growth factor reduced (GFR) Matrigel. In addition, the 2 μg/ml CP was used to treat cultured HUVECs. Sodium dodecyl sulphate polyacrylamide electrophoresis (SDS-PAGE) and western blotting were used to determine phosphorylation levels of protein kinase B (Akt) and ribosomal protein S6 kinase (S6K). CP was successfully isolated and purified using anion exchange chromatography. The effect of CP on tube formation was not significant relative to the control in the HUVEC cell line. The role of CP on Akt and S6K phosphorylation still needs to be verified by using sensitive methods of quantification such as enhanced chemiluminescence (ECL) and enzyme linked immunosorbent assay (ELISA). The levels of CP activity were shown to be higher in early tumour growth than in advanced cancer suggesting that certain physiological factors could be increasing CP activity during early tumour growth. This study investigated the effect of cobalt chloride on CP activity in breast cancer cell lines. Cobalt chloride reduced CP activity in MCF-7 and promoted CP activity in MDA-MB-231.
- Full Text:
- Date Issued: 2016
The potential use of baobab (Adansonia digitata) seedcake as a commercial diet replacement and in feed formulation for broiler chickens
- Authors: Nxele, Sibusiso Kabelo
- Date: 2016
- Subjects: Broilers (Chickens) Adansonia digitata Chickens -- Feeding and feeds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12259 , vital:39224
- Description: This dissertation is composed of two trials that were aimed at evaluating the effects of partially supplementing Baobab seed cake in broiler diets. In the first trail, performance and cost analysis of feeding birds a commercial starter diet from day-old to 21-days of age; then feeding a blend of the commercial finisher diet diluted by a mixture of baobab seedcake and ground maize from day 22nd to 35th were evaluated. The trial was conducted in an environmentally controlled deep litter housing system using 160 Ross 308 chicks of mixed sex that were randomly allocated into 4 treatments consisting of 16 pens of 1X2m2 area per pen, within similar environmental conditions. The trial diets were formulated as follows: T1 was 100 percent standard commercial starter diet, as a control; T2 had 95 percent (112g) commercial starter diet and 5 percent BSC-maize blend (2g BSC: 4g Maize); T3 had 85 percent (102g) of the commercial starter diet and 18percent BSC-maize blend (6g BSC + 12g Maize); and T4 had 75 percent commercial starter diet and 25 percent BSC-maize blend (10g BSC + 20g Maize). All diets (T1, T2, T3 and T4) percentages were calculated based on 120g being 100 percent of the diet. Each treatment consisted of 40 birds and 4 replicates, each replicate consisting of 10 birds per pen. Feed and clean water were provided ad libitum. Feed allocation and body weights were measured at placement, then weekly. Feed intakes (FI), body weight gain (BWG) and feed conversion ratio (FCR) were calculated; then the cost analysis of feeding each diet was conducted. No significant differences (P>0.05) were found amongst all growth performance parameters. The cost efficient treatment to feed, which accumulated the cheapest cost of feed per weight gain (R33.62/kg gain) was T2 (5percent BSC+MM). The second trial was conducted to evaluate the effect of feeding diets containing graded levels of baoabab (A. digitata) seedcake on performance, apparent digestibility and digestive organ weights of broilers chickens. A total of 200 Ross 308 day-old chicks of mixed sex were randomly allocated into 4 treatment groups (T1, T2, T3 and T4). The trial diets were as follows: T1 (control), was a commercial starter diet; while T2, T3 and T4 diets contained baobab seedcake meal at 0, 5, 10, and 15percent; respectively. Inclusion of BSC in diets only affected FI during the first and third weeks. In the first week, FI had significant differences (P < 0.05) during the first and third week of the trial, respectively. Birds in T4 had the least FI, while those in T3 had the highest (P<0.05). In the third week, T3 birds had the highest FI (P<0.05), while T1 birds had the lowest. Significant differences for changes in bodyweight were only evident in the second and forth weeks of the study. During week 2, birds in T had the highest BWG, whereas T4 birds had the lowest (P<0.05); however, in week 4, there were no statistical differences (P>0.05) amongst birds in T1, T2 and T4; respectively, while T4 had the lowest BWG (P<0.05). The FCR was not statistically different among treatment groups, except in week 3, where it was highest in T4birds with T3 birds having the lowest (P<0.05). No significant differences (P>0.05) were observed among treatment groups for all parameters that were considered for digestibility and digestive organ weights. Due to the fact that two different trials were conducted, it was concluded that blend of baobab seedcake and maize from the first trial can be supplemented up to 5 percent replacement level for optimum production; while up to 10 percent baobab seedcake graded level can be used on the second trial without resulting in any negative consequences on growth performance, nutrient utilization and digestive organ weights.
- Full Text:
- Date Issued: 2016
- Authors: Nxele, Sibusiso Kabelo
- Date: 2016
- Subjects: Broilers (Chickens) Adansonia digitata Chickens -- Feeding and feeds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12259 , vital:39224
- Description: This dissertation is composed of two trials that were aimed at evaluating the effects of partially supplementing Baobab seed cake in broiler diets. In the first trail, performance and cost analysis of feeding birds a commercial starter diet from day-old to 21-days of age; then feeding a blend of the commercial finisher diet diluted by a mixture of baobab seedcake and ground maize from day 22nd to 35th were evaluated. The trial was conducted in an environmentally controlled deep litter housing system using 160 Ross 308 chicks of mixed sex that were randomly allocated into 4 treatments consisting of 16 pens of 1X2m2 area per pen, within similar environmental conditions. The trial diets were formulated as follows: T1 was 100 percent standard commercial starter diet, as a control; T2 had 95 percent (112g) commercial starter diet and 5 percent BSC-maize blend (2g BSC: 4g Maize); T3 had 85 percent (102g) of the commercial starter diet and 18percent BSC-maize blend (6g BSC + 12g Maize); and T4 had 75 percent commercial starter diet and 25 percent BSC-maize blend (10g BSC + 20g Maize). All diets (T1, T2, T3 and T4) percentages were calculated based on 120g being 100 percent of the diet. Each treatment consisted of 40 birds and 4 replicates, each replicate consisting of 10 birds per pen. Feed and clean water were provided ad libitum. Feed allocation and body weights were measured at placement, then weekly. Feed intakes (FI), body weight gain (BWG) and feed conversion ratio (FCR) were calculated; then the cost analysis of feeding each diet was conducted. No significant differences (P>0.05) were found amongst all growth performance parameters. The cost efficient treatment to feed, which accumulated the cheapest cost of feed per weight gain (R33.62/kg gain) was T2 (5percent BSC+MM). The second trial was conducted to evaluate the effect of feeding diets containing graded levels of baoabab (A. digitata) seedcake on performance, apparent digestibility and digestive organ weights of broilers chickens. A total of 200 Ross 308 day-old chicks of mixed sex were randomly allocated into 4 treatment groups (T1, T2, T3 and T4). The trial diets were as follows: T1 (control), was a commercial starter diet; while T2, T3 and T4 diets contained baobab seedcake meal at 0, 5, 10, and 15percent; respectively. Inclusion of BSC in diets only affected FI during the first and third weeks. In the first week, FI had significant differences (P < 0.05) during the first and third week of the trial, respectively. Birds in T4 had the least FI, while those in T3 had the highest (P<0.05). In the third week, T3 birds had the highest FI (P<0.05), while T1 birds had the lowest. Significant differences for changes in bodyweight were only evident in the second and forth weeks of the study. During week 2, birds in T had the highest BWG, whereas T4 birds had the lowest (P<0.05); however, in week 4, there were no statistical differences (P>0.05) amongst birds in T1, T2 and T4; respectively, while T4 had the lowest BWG (P<0.05). The FCR was not statistically different among treatment groups, except in week 3, where it was highest in T4birds with T3 birds having the lowest (P<0.05). No significant differences (P>0.05) were observed among treatment groups for all parameters that were considered for digestibility and digestive organ weights. Due to the fact that two different trials were conducted, it was concluded that blend of baobab seedcake and maize from the first trial can be supplemented up to 5 percent replacement level for optimum production; while up to 10 percent baobab seedcake graded level can be used on the second trial without resulting in any negative consequences on growth performance, nutrient utilization and digestive organ weights.
- Full Text:
- Date Issued: 2016
The phytogeography of Southern Mistbelt Forests of the Eastern Cape, South Africa
- Authors: Matiwane, Aviwe
- Date: 2016
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3224 , vital:20393
- Description: In the Eastern Cape, a moisture gradient (from west to east) exists along the Escarpment where patches of Southern Mistbelt Forests (SMF) occur. There is a notable profusion of plants in these forests, but the factors that drive plant species composition and abundance in these patches is poorly understood and such knowledge is critical if we are to address or mitigate the problems imposed by global change. Many of our ideas on plant community assembly are based on the premise that species differ in their environmental requirements for successful regeneration, especially when young. The aims of this study were to document the floristic diversity of poorly known patches of Southern Mistbelt Forests in the Eastern Cape and identify the environmental factors that influence plant community composition in these forest patches. Twenty six forest patches across the Eastern Cape were sampled. In each forest 400m2 circular plots were constructed. The diameter at breast height and stem counts for the tree species was taken and the % cover of the herbaceous species was recorded. General collections were also made to supplement the plot data in order to obtain a comprehensive flora for each forest patch. All sampling was done during the summer season of 2013 and 2014. Using plot data, Hierarchal Cluster Analysis and Multidimensional Scaling Analysis were done to compare similarities between patches. Plots from the same forest patch clustered which indicated that the species composition in each forest patch was unique. However, this pattern went down when only tree species were considered. Plant diversity also varied between patches; with those located in the east being generally more diverse than those in the west are. Clustering patterns in fragmented communities and differences in species diversity indicate evidence of species “nestedness”. Analysis of nestedness indicated that these forest patches were significantly nested. To identify which environmental variables might be correlated with both species diversity and nestedness, twelve environmental variables was selected for analysis using Canonical Correspondence Analysis and Principal Component Analysis. Results show that Mean Annual Precipitation, Mean Annual Potential Evapotranspiration, and percentage of Organic Matter of the soil were most strongly correlated with the patterns of diversity observed in these forest patches. Regression analysis indicated that Mean Annual Precipitation accounted for most of the variation in species diversity, especially for the herbaceous species. The herbaceous species thus show a greater sensitivity to “climate filtering” as a consequence of rainfall gradients. With the implementation of suitable monitoring programs, changes in abundance or even local extinction of these species can act as an early warning indicator of the possible long-term effects of climate change on forest communities.
- Full Text:
- Date Issued: 2016
- Authors: Matiwane, Aviwe
- Date: 2016
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3224 , vital:20393
- Description: In the Eastern Cape, a moisture gradient (from west to east) exists along the Escarpment where patches of Southern Mistbelt Forests (SMF) occur. There is a notable profusion of plants in these forests, but the factors that drive plant species composition and abundance in these patches is poorly understood and such knowledge is critical if we are to address or mitigate the problems imposed by global change. Many of our ideas on plant community assembly are based on the premise that species differ in their environmental requirements for successful regeneration, especially when young. The aims of this study were to document the floristic diversity of poorly known patches of Southern Mistbelt Forests in the Eastern Cape and identify the environmental factors that influence plant community composition in these forest patches. Twenty six forest patches across the Eastern Cape were sampled. In each forest 400m2 circular plots were constructed. The diameter at breast height and stem counts for the tree species was taken and the % cover of the herbaceous species was recorded. General collections were also made to supplement the plot data in order to obtain a comprehensive flora for each forest patch. All sampling was done during the summer season of 2013 and 2014. Using plot data, Hierarchal Cluster Analysis and Multidimensional Scaling Analysis were done to compare similarities between patches. Plots from the same forest patch clustered which indicated that the species composition in each forest patch was unique. However, this pattern went down when only tree species were considered. Plant diversity also varied between patches; with those located in the east being generally more diverse than those in the west are. Clustering patterns in fragmented communities and differences in species diversity indicate evidence of species “nestedness”. Analysis of nestedness indicated that these forest patches were significantly nested. To identify which environmental variables might be correlated with both species diversity and nestedness, twelve environmental variables was selected for analysis using Canonical Correspondence Analysis and Principal Component Analysis. Results show that Mean Annual Precipitation, Mean Annual Potential Evapotranspiration, and percentage of Organic Matter of the soil were most strongly correlated with the patterns of diversity observed in these forest patches. Regression analysis indicated that Mean Annual Precipitation accounted for most of the variation in species diversity, especially for the herbaceous species. The herbaceous species thus show a greater sensitivity to “climate filtering” as a consequence of rainfall gradients. With the implementation of suitable monitoring programs, changes in abundance or even local extinction of these species can act as an early warning indicator of the possible long-term effects of climate change on forest communities.
- Full Text:
- Date Issued: 2016
The maturity of project management in engineering consulting firms
- Authors: Machite, Kennedy
- Date: 2016
- Subjects: Project management Consulting engineers -- South Africa , Engineering firms -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/18409 , vital:28634
- Description: With a considerable number of built environment projects not being completed successfully, this study was undertaken to investigate how effectively consulting engineering firms are applying project management principles in the way they manage projects. This was achieved by measuring the project management maturity levels of consulting engineering firms. Maturity levels were measured for each of the ten knowledge areas of the Project Management Institute’s Project Management Body of Knowledge to determine areas where consulting engineering firms perform below expectation and as a result determine probable causes of project failures. The maturity of the firm was then calculated as the average of the maturity for the knowledge areas. The study found that consulting engineering firms have higher levels of project management maturity than the average for the construction and civil engineering sector. Apart from risk and procurement management, all the other knowledge areas have higher maturity levels than the corresponding construction and civil engineering knowledge areas. Although the overall maturity results indicate that the larger firms are more mature in their project management practices than the smaller firms, the individual knowledge areas are inconsistent. The study reveals that consulting engineering firms are weakest in the risk management, human resources and stakeholder management knowledge areas. There is limited literature available on the status of project management, project management methodologies, and performance of consulting projects in the engineering environment (Labuschagne & Steyn, 2010:70). There is need for future studies to establish a methodology developed specifically for the Consulting Engineering Firms in line with what Labuschagne & Steyn (2010) started and a Project Management Maturity Model specific to the Consulting Engineering Industry.
- Full Text:
- Date Issued: 2016
- Authors: Machite, Kennedy
- Date: 2016
- Subjects: Project management Consulting engineers -- South Africa , Engineering firms -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/18409 , vital:28634
- Description: With a considerable number of built environment projects not being completed successfully, this study was undertaken to investigate how effectively consulting engineering firms are applying project management principles in the way they manage projects. This was achieved by measuring the project management maturity levels of consulting engineering firms. Maturity levels were measured for each of the ten knowledge areas of the Project Management Institute’s Project Management Body of Knowledge to determine areas where consulting engineering firms perform below expectation and as a result determine probable causes of project failures. The maturity of the firm was then calculated as the average of the maturity for the knowledge areas. The study found that consulting engineering firms have higher levels of project management maturity than the average for the construction and civil engineering sector. Apart from risk and procurement management, all the other knowledge areas have higher maturity levels than the corresponding construction and civil engineering knowledge areas. Although the overall maturity results indicate that the larger firms are more mature in their project management practices than the smaller firms, the individual knowledge areas are inconsistent. The study reveals that consulting engineering firms are weakest in the risk management, human resources and stakeholder management knowledge areas. There is limited literature available on the status of project management, project management methodologies, and performance of consulting projects in the engineering environment (Labuschagne & Steyn, 2010:70). There is need for future studies to establish a methodology developed specifically for the Consulting Engineering Firms in line with what Labuschagne & Steyn (2010) started and a Project Management Maturity Model specific to the Consulting Engineering Industry.
- Full Text:
- Date Issued: 2016
The influence of aspirations on changing livelihood strategies in rural households of Ndabakazi villages in the Eastern Cape
- Authors: Zantsi, Siphe
- Date: 2016
- Subjects: Households -- Economic aspects -- South Africa -- Eastern Cape Rural development projects -- South Africa -- Eastern Cape Sustainable development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5653 , vital:29357
- Description: The objective of this study is to explore the role of aspirations on changing livelihood strategies of rural households of Ndabakazi villages in the Eastern Cape. A sample of 80 respondents was chosen randomly for the household survey and semi-structured questionnaires were used to collect the data. Focus group discussions were also used to supplement the household survey. The data was descriptively analysed using a triangulation method. The findings show that social grants, mainly pensions and non-farm employment, and child support grants are the major sources of income. The majority of the households own five hectares of land and more, in which they grow crops only in gardens adjacent to their homes. However, 29 percent do not produce any crops at all. Farming contributes a small portion to the household income. The choice of farming is more powerful than the external factors. Interest in farming is minimal and can be related to the declining farming activities; therefore, household aspirations have an influence on changing livelihood aspirations. In the case of the rural areas of Ndabakazi – as indeed in many other parts of South Africa - policies of rural development mostly take a top-down approach; as a result most of these policies do not become effective in achieving the intended outcome. Development practitioners should incorporate beneficiaries when planning so as to tailor the development initiatives with the aspirations of local people for them to be effect and achieve intended goals thus a bottom-up approach. The notion that rural household farming activities have declined because they lack inputs, farming implements other necessary support is not always true. Some households are not interested in farming and they cannot be forced.
- Full Text:
- Date Issued: 2016
- Authors: Zantsi, Siphe
- Date: 2016
- Subjects: Households -- Economic aspects -- South Africa -- Eastern Cape Rural development projects -- South Africa -- Eastern Cape Sustainable development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5653 , vital:29357
- Description: The objective of this study is to explore the role of aspirations on changing livelihood strategies of rural households of Ndabakazi villages in the Eastern Cape. A sample of 80 respondents was chosen randomly for the household survey and semi-structured questionnaires were used to collect the data. Focus group discussions were also used to supplement the household survey. The data was descriptively analysed using a triangulation method. The findings show that social grants, mainly pensions and non-farm employment, and child support grants are the major sources of income. The majority of the households own five hectares of land and more, in which they grow crops only in gardens adjacent to their homes. However, 29 percent do not produce any crops at all. Farming contributes a small portion to the household income. The choice of farming is more powerful than the external factors. Interest in farming is minimal and can be related to the declining farming activities; therefore, household aspirations have an influence on changing livelihood aspirations. In the case of the rural areas of Ndabakazi – as indeed in many other parts of South Africa - policies of rural development mostly take a top-down approach; as a result most of these policies do not become effective in achieving the intended outcome. Development practitioners should incorporate beneficiaries when planning so as to tailor the development initiatives with the aspirations of local people for them to be effect and achieve intended goals thus a bottom-up approach. The notion that rural household farming activities have declined because they lack inputs, farming implements other necessary support is not always true. Some households are not interested in farming and they cannot be forced.
- Full Text:
- Date Issued: 2016
The importance of habitat use in the foraging behaviour of village chacma baboons (Papio ursinus, Cercopithecidae: Primates) in Hogsback, Eastern Cape
- Authors: Pamla, Lwandiso
- Date: 2016
- Subjects: Chacma baboon -- Behavior -- South Africa -- Eastern Cape Cercopithecidae Primates -- Behavior
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8055 , vital:31494
- Description: Baboons are among the most widespread primates in Africa because they are able to adapt their foraging behaviour and omnivorous diet under challenging and changing conditions. They are attracted by food, shelter and water on human-owned properties, which brings them into conflict with the residents in Hogsback, Eastern Cape, South Africa, and results in them being shot, trapped or poisoned. To quantify the proportion of food baboons obtain from raiding human properties and to assess the quality of this food, I recorded activity budgets for foraging and movement in two free-ranging troops (Evie’s and Nola’s troops) using direct field observation. I determined home range sizes using GIS methods. I hypothesised that a troop that frequents more human-modified areas should have smaller home ranges, higher densities and forage less than a troop that spends more time in natural habitats, irrespective of troop size, because of more readily accessible food sources. The three methods I used (100 percent minimum convex method, 95 percent fixed kernel method and quadrat method) revealed that Evie’s troop used more human-modified habitat, but had a larger home range than Nola’s troop. The troop sizes have been stable for the past four years: at last count, Evie’s troop had 47 individuals and Nola’s, 38 individuals. During my field study I also recorded diverse vocalisations made by the animals, as an aid to detecting and identifying the troops and understanding individual interactions. Responses to the presence of baboons of many of the local residents – whether affluent and living on semi-urban estates, or impoverished and hunting for food – do not augur well for the future of Hogsback’s baboons. Affluent residents with horticultural gardens occasionally shoot baboons that venture on to their properties, while rural occupants hunt baboons in their natural environment. Both of these responses cause troop disruption and decreased troop size, possibly leading to local troop extinctions.
- Full Text:
- Date Issued: 2016
- Authors: Pamla, Lwandiso
- Date: 2016
- Subjects: Chacma baboon -- Behavior -- South Africa -- Eastern Cape Cercopithecidae Primates -- Behavior
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8055 , vital:31494
- Description: Baboons are among the most widespread primates in Africa because they are able to adapt their foraging behaviour and omnivorous diet under challenging and changing conditions. They are attracted by food, shelter and water on human-owned properties, which brings them into conflict with the residents in Hogsback, Eastern Cape, South Africa, and results in them being shot, trapped or poisoned. To quantify the proportion of food baboons obtain from raiding human properties and to assess the quality of this food, I recorded activity budgets for foraging and movement in two free-ranging troops (Evie’s and Nola’s troops) using direct field observation. I determined home range sizes using GIS methods. I hypothesised that a troop that frequents more human-modified areas should have smaller home ranges, higher densities and forage less than a troop that spends more time in natural habitats, irrespective of troop size, because of more readily accessible food sources. The three methods I used (100 percent minimum convex method, 95 percent fixed kernel method and quadrat method) revealed that Evie’s troop used more human-modified habitat, but had a larger home range than Nola’s troop. The troop sizes have been stable for the past four years: at last count, Evie’s troop had 47 individuals and Nola’s, 38 individuals. During my field study I also recorded diverse vocalisations made by the animals, as an aid to detecting and identifying the troops and understanding individual interactions. Responses to the presence of baboons of many of the local residents – whether affluent and living on semi-urban estates, or impoverished and hunting for food – do not augur well for the future of Hogsback’s baboons. Affluent residents with horticultural gardens occasionally shoot baboons that venture on to their properties, while rural occupants hunt baboons in their natural environment. Both of these responses cause troop disruption and decreased troop size, possibly leading to local troop extinctions.
- Full Text:
- Date Issued: 2016
The implications of the 2014 construction regulations for the Department of Public Works procurement system
- Authors: Matete, Kenevoe Rose
- Date: 2016
- Subjects: Construction industry -- Safety regulations -- South Africa Construction industry -- Standards -- South Africa Industrial procurement -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/10309 , vital:26651
- Description: The Organisation of Economic Co-operation and Development (OECD) notes that regulations seek to make improvements by changing individual or organisational behaviour in ways that generate positive impacts in terms of solving societal and economic problems. At its most basic level, regulations are designed to work according to implementation, leading to changes in behaviours that, in turn, lead to changes in outcomes. Such outcomes can be satisfaction in terms of an underlying problem or other (hopefully positive) changes in conditions in the world. Following this premise, this research project investigates the implications of the 2014 Construction Regulations for the Department of Public Works’ procurement system. The study also examines the contents of the construction Regulations; the impact of the Construction Regulations 2014 – permit-to-work; client / contractor procurement issues; the enforcement of compliance to permit-to-work requirements, and education and training demands in relation to health and safety (H&S) competency. The study shows that even though industry role players are relatively familiar with the Construction Regulations 2014, there is a common concern regarding competency (education and training) levels required for the implementation of the permit-to-work requirement of the regulations. The concerns focus on the ability of the Department of Labour (DoL) to process the permits. Based on the study’s findings, the research concludes that there would be cost implications for project actors when implementing the permit-to-work requirement and this cost factor could delay project initiation and planning, as well as service delivery.
- Full Text:
- Date Issued: 2016
- Authors: Matete, Kenevoe Rose
- Date: 2016
- Subjects: Construction industry -- Safety regulations -- South Africa Construction industry -- Standards -- South Africa Industrial procurement -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/10309 , vital:26651
- Description: The Organisation of Economic Co-operation and Development (OECD) notes that regulations seek to make improvements by changing individual or organisational behaviour in ways that generate positive impacts in terms of solving societal and economic problems. At its most basic level, regulations are designed to work according to implementation, leading to changes in behaviours that, in turn, lead to changes in outcomes. Such outcomes can be satisfaction in terms of an underlying problem or other (hopefully positive) changes in conditions in the world. Following this premise, this research project investigates the implications of the 2014 Construction Regulations for the Department of Public Works’ procurement system. The study also examines the contents of the construction Regulations; the impact of the Construction Regulations 2014 – permit-to-work; client / contractor procurement issues; the enforcement of compliance to permit-to-work requirements, and education and training demands in relation to health and safety (H&S) competency. The study shows that even though industry role players are relatively familiar with the Construction Regulations 2014, there is a common concern regarding competency (education and training) levels required for the implementation of the permit-to-work requirement of the regulations. The concerns focus on the ability of the Department of Labour (DoL) to process the permits. Based on the study’s findings, the research concludes that there would be cost implications for project actors when implementing the permit-to-work requirement and this cost factor could delay project initiation and planning, as well as service delivery.
- Full Text:
- Date Issued: 2016
The impact of three different footwear conditions on individual biomechanical, physiological and perceptual responses during running.
- Authors: McDougall, Justin John
- Date: 2016
- Subjects: Running -- Physiological aspects , Running shoes -- Physiological aspects , Running -- Health aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5177 , http://hdl.handle.net/10962/d1019988
- Description: Background: Despite the introduction of running footwear in the 1970’s, running injury rates continue to be unacceptably high. The subsequent revival of barefoot running and the introduction of minimalist footwear occurred, in an attempt to reduce injury rates and increase performance. There is much contention in the literature around the effectiveness of these footwear conditions. Furthermore individual responses have recently been proposed to provide more accurate and reflective conclusions than the use of mean data. Objectives: Twofold: a) to compare the biomechanical, physiological and perceptual responses between the shod, minimalist and barefoot footwear conditions and b) to assess and compare individual responses under these footwear conditions. Methods: 26 well-trained, male, habitually shod endurance runners, aged between 18 - 30 years completed three experimental sessions on an indoor runway and motorized treadmill. Each session was completed in either the shod, minimalist or barefoot condition, running at 15km.h-1. Variables assessed included stride rate, stride length, impact peak, vertical impact and average loading rate and strike time (biomechanical); heart rate, oxygen consumption and electromyography (physiological); and rating of perceived exertion and body discomfort (perceptual). Results: Biomechanics – Stride rate and stride length showed a significant (p<0.001) increase and decrease respectively when running in the minimalist or barefoot conditions versus shod. Running barefoot versus the minimalist and shod conditions resulted in a significantly (p<0.001) greater vertical impact loading rate. Strike time was significantly (p=0.008) reduced running in the minimalist and barefoot conditions versus shod. Physiology – Running barefoot versus shod resulted in a significantly (p=0.02) reduced heart rate and Tibialis Anterior activity (p=0.005). There was a large variability in individual responses for many variables, with responders and non-responders seen. Conclusion: The study suggests that there are significant differences between all three forms of running for some variables. It was further noted that there is support for the proposal that individual responses are highly variable and should be analysed accordingly
- Full Text:
- Date Issued: 2016
- Authors: McDougall, Justin John
- Date: 2016
- Subjects: Running -- Physiological aspects , Running shoes -- Physiological aspects , Running -- Health aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5177 , http://hdl.handle.net/10962/d1019988
- Description: Background: Despite the introduction of running footwear in the 1970’s, running injury rates continue to be unacceptably high. The subsequent revival of barefoot running and the introduction of minimalist footwear occurred, in an attempt to reduce injury rates and increase performance. There is much contention in the literature around the effectiveness of these footwear conditions. Furthermore individual responses have recently been proposed to provide more accurate and reflective conclusions than the use of mean data. Objectives: Twofold: a) to compare the biomechanical, physiological and perceptual responses between the shod, minimalist and barefoot footwear conditions and b) to assess and compare individual responses under these footwear conditions. Methods: 26 well-trained, male, habitually shod endurance runners, aged between 18 - 30 years completed three experimental sessions on an indoor runway and motorized treadmill. Each session was completed in either the shod, minimalist or barefoot condition, running at 15km.h-1. Variables assessed included stride rate, stride length, impact peak, vertical impact and average loading rate and strike time (biomechanical); heart rate, oxygen consumption and electromyography (physiological); and rating of perceived exertion and body discomfort (perceptual). Results: Biomechanics – Stride rate and stride length showed a significant (p<0.001) increase and decrease respectively when running in the minimalist or barefoot conditions versus shod. Running barefoot versus the minimalist and shod conditions resulted in a significantly (p<0.001) greater vertical impact loading rate. Strike time was significantly (p=0.008) reduced running in the minimalist and barefoot conditions versus shod. Physiology – Running barefoot versus shod resulted in a significantly (p=0.02) reduced heart rate and Tibialis Anterior activity (p=0.005). There was a large variability in individual responses for many variables, with responders and non-responders seen. Conclusion: The study suggests that there are significant differences between all three forms of running for some variables. It was further noted that there is support for the proposal that individual responses are highly variable and should be analysed accordingly
- Full Text:
- Date Issued: 2016
The GARCH-EVT-Copula model and simulation in scenario-based asset allocation
- McEwan, Peter Gareth Fredric
- Authors: McEwan, Peter Gareth Fredric
- Date: 2016
- Subjects: Extreme value theory GARCH model
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/11732 , vital:26961
- Description: Financial market integration, in particular, portfolio allocations from advanced economies to South African markets, continues to strengthen volatility linkages and quicken volatility transmissions between participating markets. Largely as a result, South African portfolios are net recipients of returns and volatility shocks emanating from major world markets. In light of these, and other, sources of risk, this dissertation proposes a methodology to improve risk management systems in funds by building a contemporary asset allocation framework that offers practitioners an opportunity to explicitly model combinations of hypothesised global risks and the effects on their investments. The framework models portfolio return variables and their key risk driver variables separately and then joins them to model their combined dependence structure. The separate modelling of univariate and multivariate (MV) components admits the benefit of capturing the data generating processes with improved accuracy. Univariate variables were modelled using ARMA-GARCH-family structures paired with a variety of skewed and leptokurtic conditional distributions. Model residuals were fit using the Peaks-over-Threshold method from Extreme Value Theory for the tails and a non-parametric, kernel density for the interior, forming a completed semi-parametric distribution (SPD) for each variable. Asset and risk factor returns were then combined and their dependence structure jointly modelled with a MV Student t copula. Finally, the SPD margins and Student t copula were used to construct a MV meta t distribution. Monte Carlo simulations were generated from the fitted MV meta t distribution on which an out-of-sample test was conducted. The 2014-to-2015 horizon served to proxy as an out-of-sample, forward-looking scenario for a set of key risk factors against which a hypothetical, diversified portfolio was optimised. Traditional mean-variance and contemporary mean-CVaR optimisation techniques were used and their results compared. As an addendum, performance over the in-sample 2008 financial crisis was reported. The final Objective (7) addressed management and conservation strategies for the NMBM. The NMBM wetland database that was produced during this research is currently being used by the Municipality and will be added to the latest National Wetland Map. From the database, and tools developed in this research, approximately 90 wetlands have been identified as being highly vulnerable due to anthropogenic and environmental factors (Chapter 6) and should be earmarked as key conservation priority areas. Based on field experience and data collected, this study has also made conservation and rehabilitation recommendations for eight locations. Recommendations are also provided for six more wetland systems (or regions) that should be prioritised for further research, as these systems lack fundamental information on where the threat of anthropogenic activities affecting them is greatest. This study has made a significant contribution to understanding the underlying geomorphological processes in depressions, seeps and wetland flats. The desktop mapping component of this study illustrated the dominance of wetlands in the wetter parts of the Municipality. Perched wetland systems were identified in the field, on shallow bedrock, calcrete or clay. The prevalence of these perches in depressions, seeps and wetland flats also highlighted the importance of rainfall in driving wetland formation, by allowing water to pool on these perches, in the NMBM. These perches are likely to be a key factor in the high number of small, ephemeral wetlands that were observed in the study area, compared to other semi-arid regions. Therefore, this research highlights the value of multi-faceted and multi-scalar wetland research and how similar approaches should be used in future research methods has been highlighted. The approach used, along with the tools/methods developed in this study have facilitated the establishment of priority areas for conservation and management within the NMBM. Furthermore, the research approach has revealed emergent wetland properties that are only apparent when looking at different spatial scales. This research has highlighted the complex biological and geomorphological interactions between wetlands that operate over various spatial and temporal scales. As such, wetland management should occur across a wetland complex, rather than individual sites, to account for these multi-scalar influences.
- Full Text:
- Date Issued: 2016
- Authors: McEwan, Peter Gareth Fredric
- Date: 2016
- Subjects: Extreme value theory GARCH model
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/11732 , vital:26961
- Description: Financial market integration, in particular, portfolio allocations from advanced economies to South African markets, continues to strengthen volatility linkages and quicken volatility transmissions between participating markets. Largely as a result, South African portfolios are net recipients of returns and volatility shocks emanating from major world markets. In light of these, and other, sources of risk, this dissertation proposes a methodology to improve risk management systems in funds by building a contemporary asset allocation framework that offers practitioners an opportunity to explicitly model combinations of hypothesised global risks and the effects on their investments. The framework models portfolio return variables and their key risk driver variables separately and then joins them to model their combined dependence structure. The separate modelling of univariate and multivariate (MV) components admits the benefit of capturing the data generating processes with improved accuracy. Univariate variables were modelled using ARMA-GARCH-family structures paired with a variety of skewed and leptokurtic conditional distributions. Model residuals were fit using the Peaks-over-Threshold method from Extreme Value Theory for the tails and a non-parametric, kernel density for the interior, forming a completed semi-parametric distribution (SPD) for each variable. Asset and risk factor returns were then combined and their dependence structure jointly modelled with a MV Student t copula. Finally, the SPD margins and Student t copula were used to construct a MV meta t distribution. Monte Carlo simulations were generated from the fitted MV meta t distribution on which an out-of-sample test was conducted. The 2014-to-2015 horizon served to proxy as an out-of-sample, forward-looking scenario for a set of key risk factors against which a hypothetical, diversified portfolio was optimised. Traditional mean-variance and contemporary mean-CVaR optimisation techniques were used and their results compared. As an addendum, performance over the in-sample 2008 financial crisis was reported. The final Objective (7) addressed management and conservation strategies for the NMBM. The NMBM wetland database that was produced during this research is currently being used by the Municipality and will be added to the latest National Wetland Map. From the database, and tools developed in this research, approximately 90 wetlands have been identified as being highly vulnerable due to anthropogenic and environmental factors (Chapter 6) and should be earmarked as key conservation priority areas. Based on field experience and data collected, this study has also made conservation and rehabilitation recommendations for eight locations. Recommendations are also provided for six more wetland systems (or regions) that should be prioritised for further research, as these systems lack fundamental information on where the threat of anthropogenic activities affecting them is greatest. This study has made a significant contribution to understanding the underlying geomorphological processes in depressions, seeps and wetland flats. The desktop mapping component of this study illustrated the dominance of wetlands in the wetter parts of the Municipality. Perched wetland systems were identified in the field, on shallow bedrock, calcrete or clay. The prevalence of these perches in depressions, seeps and wetland flats also highlighted the importance of rainfall in driving wetland formation, by allowing water to pool on these perches, in the NMBM. These perches are likely to be a key factor in the high number of small, ephemeral wetlands that were observed in the study area, compared to other semi-arid regions. Therefore, this research highlights the value of multi-faceted and multi-scalar wetland research and how similar approaches should be used in future research methods has been highlighted. The approach used, along with the tools/methods developed in this study have facilitated the establishment of priority areas for conservation and management within the NMBM. Furthermore, the research approach has revealed emergent wetland properties that are only apparent when looking at different spatial scales. This research has highlighted the complex biological and geomorphological interactions between wetlands that operate over various spatial and temporal scales. As such, wetland management should occur across a wetland complex, rather than individual sites, to account for these multi-scalar influences.
- Full Text:
- Date Issued: 2016