Effect of Moringa oleifera leaf meal on growth performance, faecal ammonia emissions, carcass characteristics and the quality of meat from broiler chickens
- Authors: Mxunyelwa, Avela,
- Date: 2016
- Subjects: Moringa oleifera Meat -- Quality Broilers (Chickens)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15034 , vital:40154
- Description: The objective of the study was to determine growth performance, faecal ammonia gas emission, carcass characteristics and physico-chemical meat traits from broilers fed one of the four dietary treatments, containing 0percent, 1percent, 3percent or 5percent Moringa oleifera leaf meal (MOLM) (T1, T2, T3, and T4, respectively). Dietary treatments were formulated to be isonitrogenous and isocaloric for a starter (0-14 days), grower (15-21days) and finisher (22-35 days). A total of 160 day old Cobb 500 broiler chickens, initially weighing an average of 45g were randomly allocated to each of the dietary treatments, each with four replicates, in 16 pens. Feed and water were offered ad libitum. Feed intakes (FI), average daily gain (ADG), body weight gain (BWG) and feed conversion efficiency (FCE) were measured weekly. At the end of the feeding trial, the feed was withdrawn from the birds for 12 hours with water available ad libitum and the birds were slaughtered using standard abattoir procedures. The breast muscle of each carcass was sampled for meat quality analysis. Organ and carcass weights differences were measured. Birds fed with T1 had the highest FI. Birds fed with T4 had the best FCE at day 14, 21 and 35. At day 7 and 35, there were no significant differences in FCE in all the treatments. At 0 to 35 days, faecal ammonia emission decreased (P<0.05) as MOLM concentration and age of birds increased. Moringa fed broilers had the highest body weights in all the periods despite the incorporation level in the diet. The results showed that inclusion of MOLM had a significant effect (P<0.05) on the heart, neck, and head weights but had no significant effect on liver, gizzard, intestine and feet. Broilers fed with T1 had heavier heart, neck and head weights compared to MOLM fed broilers. In terms of carcass traits, MOLM had a significant effect (P<0.05) on wings and thighs but had no significant effect (P>0.05) on breast and drumsticks. Moringa oleifera leaf meal had a significant effect on carcass weights, control diet had heavier weights (1185g ± 28.96) compared to chickens fed with MOLM diets (1121g±28.96, 1070g ± 28.96, 1030g± 28.96). Broilers fed with MOLM had higher values of lightness (L*) and (b*) values (P<0.05) at 45 minutes and 24 hours and no difference was observed in redness (a*) at 45 minutes and 24 hours. The L* values dropped at 24 hours for all the treatments and MOLM fed broilers had the lowest values (46.59 ± 0.76,46 ± 0.76,49 ± 0.76) compared to the control diet (50 ± 0.76). The pH levels were comparable after 24 hours; T2 had the highest pH values (5.95 ± 0.024) compared to other treatments (5.90 ± 0.024, 5.75 ± 0.024, 5.73 ± 0.024). The results of this study demonstrated that even though the FI was reduced in MOLM fed broilers, they efficiently consumed and used nutrients, as a result MOLM fed birds had higher weights and low ammonia concentration throughout the experiment, which may improve the house environment without affecting the quality of meat.
- Full Text:
- Date Issued: 2016
- Authors: Mxunyelwa, Avela,
- Date: 2016
- Subjects: Moringa oleifera Meat -- Quality Broilers (Chickens)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15034 , vital:40154
- Description: The objective of the study was to determine growth performance, faecal ammonia gas emission, carcass characteristics and physico-chemical meat traits from broilers fed one of the four dietary treatments, containing 0percent, 1percent, 3percent or 5percent Moringa oleifera leaf meal (MOLM) (T1, T2, T3, and T4, respectively). Dietary treatments were formulated to be isonitrogenous and isocaloric for a starter (0-14 days), grower (15-21days) and finisher (22-35 days). A total of 160 day old Cobb 500 broiler chickens, initially weighing an average of 45g were randomly allocated to each of the dietary treatments, each with four replicates, in 16 pens. Feed and water were offered ad libitum. Feed intakes (FI), average daily gain (ADG), body weight gain (BWG) and feed conversion efficiency (FCE) were measured weekly. At the end of the feeding trial, the feed was withdrawn from the birds for 12 hours with water available ad libitum and the birds were slaughtered using standard abattoir procedures. The breast muscle of each carcass was sampled for meat quality analysis. Organ and carcass weights differences were measured. Birds fed with T1 had the highest FI. Birds fed with T4 had the best FCE at day 14, 21 and 35. At day 7 and 35, there were no significant differences in FCE in all the treatments. At 0 to 35 days, faecal ammonia emission decreased (P<0.05) as MOLM concentration and age of birds increased. Moringa fed broilers had the highest body weights in all the periods despite the incorporation level in the diet. The results showed that inclusion of MOLM had a significant effect (P<0.05) on the heart, neck, and head weights but had no significant effect on liver, gizzard, intestine and feet. Broilers fed with T1 had heavier heart, neck and head weights compared to MOLM fed broilers. In terms of carcass traits, MOLM had a significant effect (P<0.05) on wings and thighs but had no significant effect (P>0.05) on breast and drumsticks. Moringa oleifera leaf meal had a significant effect on carcass weights, control diet had heavier weights (1185g ± 28.96) compared to chickens fed with MOLM diets (1121g±28.96, 1070g ± 28.96, 1030g± 28.96). Broilers fed with MOLM had higher values of lightness (L*) and (b*) values (P<0.05) at 45 minutes and 24 hours and no difference was observed in redness (a*) at 45 minutes and 24 hours. The L* values dropped at 24 hours for all the treatments and MOLM fed broilers had the lowest values (46.59 ± 0.76,46 ± 0.76,49 ± 0.76) compared to the control diet (50 ± 0.76). The pH levels were comparable after 24 hours; T2 had the highest pH values (5.95 ± 0.024) compared to other treatments (5.90 ± 0.024, 5.75 ± 0.024, 5.73 ± 0.024). The results of this study demonstrated that even though the FI was reduced in MOLM fed broilers, they efficiently consumed and used nutrients, as a result MOLM fed birds had higher weights and low ammonia concentration throughout the experiment, which may improve the house environment without affecting the quality of meat.
- Full Text:
- Date Issued: 2016
Effect of phosphorus application on dry matter yield and nutrient content of Mucuna Pruriens (L) in Alice
- Authors: Tshwati, Nolubabalo
- Date: 2016
- Subjects: Legumes Phosphorus Fertilizers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12326 , vital:39253
- Description: The use of herbaceous legumes such as Mucuna (Mucuna pruriens) can assist to recapitalize soil fertility depletion and improve livestock productivity in the small holder farming sector of South Africa. The objective of the study was to investigate the effect of phosphorus fertilizer application (0, 20, 40 and 60 kg P/ha) on the dry matter yield and nutritive value of Mucuna pruriens. The study was conducted at University of Fort Hare Research farm in Alice, South Africa. The research design was a randomized complete block design with three replicates per treatment. Data collection included biomass production and nutrient content of Mucuna pruriens. The forage legume was harvested at flowering stage of growth and analysed for chemical composition. The results showed that with the application of 60 kg P/ha Mucuna had the highest (P < 0.05) fresh and dry matter yield of 19.58 kg/ha and 5.41 kg/ha, respectively compared to other treatments. However, all the other treatments differed from one another. Similarly, the fresh stem and leaf fractions yield and their dry matter yields showed the same trend with application of 60 kg P/ha having the greatest yield compared to the other treatments. Nevertheless, all the treatments differed (P<0.05) from one another with P0 having the least yields. The leaf to stem ratio did not show any significant (P>0.05) difference among all the treatments ranging from 1.44 to 1.62 in fresh forage and ranging from 1.31 to 1.50 in the dry forage. In terms of dry matter content, the control treatment had the highest dry matter content of 37.78percent, however, all the other treatments did not differ significantly (P < 0.05) from each other. There was no significant effect of P application (P > 0.05) in terms of ash, EE, ADF, CP, Ca, Mg, K, Na, P, Zn, Cu, Mn and Fe of the whole plant forage among the treatments. The application of 40 kg P/ha fertilizer significantly (P < 0.05) increased the NDF (51.16percent) of the whole plant of Mucuna compared to the other treatments which did not differ (p>0.05) among themselves. Within the stem fraction there were no significant (P > 0.05) differences among the treatments for the ash, EE, ADF, NDF, and CP, hemicellulose, Ca, Mg, K, P, Zn, Cu, Mn and Fe contents. However, the application of 40 kg P/ha fertilizer significantly (P < 0.05) increased the Na (0.05percent) content of the Mucuna stem fraction. In the leaf fraction of Mucuna there was no significant (P > 0.05) differences in terms of ash, EE, ADF, NDF, CP, hemicellulose, Ca, K, P, Zn, Cu, Mn and Fe among the treatments. However, the application of 20 kg P/ha fertilizer significantly (P < 0.05) increased the Mg (0.52percent) of the Mucuna leaves compared to the other treatments. Therefore the study has shown that increase in P application (60 kg P/ha) has no major effect in the nutrient content of Mucuna. Furthermore, it is recommended that Mucuna can be grown as a protein supplement, based on the CP content values that were recorded in this study and to provide maintenance requirements for ruminants. It was therefore concluded that phosphorus fertilization particularly 60 kg P/ha is necessary and required for optimum growth of Mucuna pruriens in order to increase forage yield. Based on the nutrient content result it was concluded that there was no effect of P fertilizer application levels on the nutrient content of Mucuna pruriens in Alice.
- Full Text:
- Date Issued: 2016
- Authors: Tshwati, Nolubabalo
- Date: 2016
- Subjects: Legumes Phosphorus Fertilizers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12326 , vital:39253
- Description: The use of herbaceous legumes such as Mucuna (Mucuna pruriens) can assist to recapitalize soil fertility depletion and improve livestock productivity in the small holder farming sector of South Africa. The objective of the study was to investigate the effect of phosphorus fertilizer application (0, 20, 40 and 60 kg P/ha) on the dry matter yield and nutritive value of Mucuna pruriens. The study was conducted at University of Fort Hare Research farm in Alice, South Africa. The research design was a randomized complete block design with three replicates per treatment. Data collection included biomass production and nutrient content of Mucuna pruriens. The forage legume was harvested at flowering stage of growth and analysed for chemical composition. The results showed that with the application of 60 kg P/ha Mucuna had the highest (P < 0.05) fresh and dry matter yield of 19.58 kg/ha and 5.41 kg/ha, respectively compared to other treatments. However, all the other treatments differed from one another. Similarly, the fresh stem and leaf fractions yield and their dry matter yields showed the same trend with application of 60 kg P/ha having the greatest yield compared to the other treatments. Nevertheless, all the treatments differed (P<0.05) from one another with P0 having the least yields. The leaf to stem ratio did not show any significant (P>0.05) difference among all the treatments ranging from 1.44 to 1.62 in fresh forage and ranging from 1.31 to 1.50 in the dry forage. In terms of dry matter content, the control treatment had the highest dry matter content of 37.78percent, however, all the other treatments did not differ significantly (P < 0.05) from each other. There was no significant effect of P application (P > 0.05) in terms of ash, EE, ADF, CP, Ca, Mg, K, Na, P, Zn, Cu, Mn and Fe of the whole plant forage among the treatments. The application of 40 kg P/ha fertilizer significantly (P < 0.05) increased the NDF (51.16percent) of the whole plant of Mucuna compared to the other treatments which did not differ (p>0.05) among themselves. Within the stem fraction there were no significant (P > 0.05) differences among the treatments for the ash, EE, ADF, NDF, and CP, hemicellulose, Ca, Mg, K, P, Zn, Cu, Mn and Fe contents. However, the application of 40 kg P/ha fertilizer significantly (P < 0.05) increased the Na (0.05percent) content of the Mucuna stem fraction. In the leaf fraction of Mucuna there was no significant (P > 0.05) differences in terms of ash, EE, ADF, NDF, CP, hemicellulose, Ca, K, P, Zn, Cu, Mn and Fe among the treatments. However, the application of 20 kg P/ha fertilizer significantly (P < 0.05) increased the Mg (0.52percent) of the Mucuna leaves compared to the other treatments. Therefore the study has shown that increase in P application (60 kg P/ha) has no major effect in the nutrient content of Mucuna. Furthermore, it is recommended that Mucuna can be grown as a protein supplement, based on the CP content values that were recorded in this study and to provide maintenance requirements for ruminants. It was therefore concluded that phosphorus fertilization particularly 60 kg P/ha is necessary and required for optimum growth of Mucuna pruriens in order to increase forage yield. Based on the nutrient content result it was concluded that there was no effect of P fertilizer application levels on the nutrient content of Mucuna pruriens in Alice.
- Full Text:
- Date Issued: 2016
Effects of Pteronia incana (Blue bush) invasion on grass biomass production, soil chemical characteristics and peoples' livelihoods in Ngqushwa communal rangelands, Eastern Cape
- Authors: Ntutha, T
- Date: 2016
- Subjects: Invasive plants -- South Africa -- Eastern Cape Shrublands -- South Africa -- Eastern Cape Rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4682 , vital:28493
- Description: The objective of the study was to assess the farmers’ knowledge and perceptions of P. incana invasion and impacts on rangeland, livestock production and livelihood in four communal grazing areas. Twenty households per village that own livestock were randomly selected to conduct an interview using an open and closed ended questionnaire. In each household, an old and knowledgeable respondent about P. incana invasion was used as a selection criterion. For scientific assessment of range condition, the experiment was conducted in a 270 m x 100 m trial plots that were established in 2014. The area was divided into 3 open and 3 fenced subplots each having an area of 45 m x 100 m established laid down a slope gradient. Each plot was divided into four equal subplots to apply the control treatments. Therefore, the trial layout was a stratified block experiment of four treatments replicated three times. The four control treatments applied to P. incana invasion were chopping and resting (CR), resting without chopping (RWOC), grazing and chopping (GC), grazing without chopping (GWOC). A step point method was applied in each transect to monitor species composition and P. incana cover. On the fenced plots two exclosures of 1mx1m size were randomly distributed to make sure that resting is maintained. Within exclosures 0.25 m2quadrates in each were put randomly to measure biomass. Density of P. incana was determined from 5 m x 5 m quadrates that were placed randomly within each sub-plot. The density and height of individual shrub plant was measured. All rooted live woody plants were recorded and counted in each quadrate. The results revealed that species composition was not affected (P>0.05) by the treatments applied. The herbage height and basal cover had greater values (P<0.05) under rested plus chopping (CR) treatment followed by grazed plus chopping (GC). Grass biomass production and essential nutrients showed a greater concentration (P<0.05) under CR treatment than any treatments applied. The results on perceptions revealed that goats had the highest mean household holding number than any other livestock species across the selected villages in all the villages. Respondents indicated that both goats and cattle had equal or more importance than sheep. Three out of four villages raised cattle primarily for income generation and secondarily for cultural purposes like slaughtering during weddings ceremonies, amazila and also during woman circumcisions (Ntonjane). Similarly, goats and sheep were primarily raised for cash income generation. The results revealed that livestock population decreased over ten to twenty years (one-two decades) and poor rangeland condition is assumed to be the cause of the situation as feed is the key factor for production. The area was dominated by the grasses rather than by browse woody species so the above results are possible as the P. incana is more competitive than grasses. It was concluded that P. incana is detrimental to both rangeland and animal production. Forage and animal performance as well as farmers’ economic status (livelihoods) were negatively affected by P. incana invasion and the scientific assessment reported it to be detrimental to agriculture. Thus chopping and resting (CR) treatment resulted in a greater improvement of the basal cover, biomass production, soil nutrients as well as grass height than the other treatments applied. Therefore it can be concluded that chopping and resting the veld invaded with P. incana can improve the range and consequently animal production.
- Full Text:
- Date Issued: 2016
- Authors: Ntutha, T
- Date: 2016
- Subjects: Invasive plants -- South Africa -- Eastern Cape Shrublands -- South Africa -- Eastern Cape Rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4682 , vital:28493
- Description: The objective of the study was to assess the farmers’ knowledge and perceptions of P. incana invasion and impacts on rangeland, livestock production and livelihood in four communal grazing areas. Twenty households per village that own livestock were randomly selected to conduct an interview using an open and closed ended questionnaire. In each household, an old and knowledgeable respondent about P. incana invasion was used as a selection criterion. For scientific assessment of range condition, the experiment was conducted in a 270 m x 100 m trial plots that were established in 2014. The area was divided into 3 open and 3 fenced subplots each having an area of 45 m x 100 m established laid down a slope gradient. Each plot was divided into four equal subplots to apply the control treatments. Therefore, the trial layout was a stratified block experiment of four treatments replicated three times. The four control treatments applied to P. incana invasion were chopping and resting (CR), resting without chopping (RWOC), grazing and chopping (GC), grazing without chopping (GWOC). A step point method was applied in each transect to monitor species composition and P. incana cover. On the fenced plots two exclosures of 1mx1m size were randomly distributed to make sure that resting is maintained. Within exclosures 0.25 m2quadrates in each were put randomly to measure biomass. Density of P. incana was determined from 5 m x 5 m quadrates that were placed randomly within each sub-plot. The density and height of individual shrub plant was measured. All rooted live woody plants were recorded and counted in each quadrate. The results revealed that species composition was not affected (P>0.05) by the treatments applied. The herbage height and basal cover had greater values (P<0.05) under rested plus chopping (CR) treatment followed by grazed plus chopping (GC). Grass biomass production and essential nutrients showed a greater concentration (P<0.05) under CR treatment than any treatments applied. The results on perceptions revealed that goats had the highest mean household holding number than any other livestock species across the selected villages in all the villages. Respondents indicated that both goats and cattle had equal or more importance than sheep. Three out of four villages raised cattle primarily for income generation and secondarily for cultural purposes like slaughtering during weddings ceremonies, amazila and also during woman circumcisions (Ntonjane). Similarly, goats and sheep were primarily raised for cash income generation. The results revealed that livestock population decreased over ten to twenty years (one-two decades) and poor rangeland condition is assumed to be the cause of the situation as feed is the key factor for production. The area was dominated by the grasses rather than by browse woody species so the above results are possible as the P. incana is more competitive than grasses. It was concluded that P. incana is detrimental to both rangeland and animal production. Forage and animal performance as well as farmers’ economic status (livelihoods) were negatively affected by P. incana invasion and the scientific assessment reported it to be detrimental to agriculture. Thus chopping and resting (CR) treatment resulted in a greater improvement of the basal cover, biomass production, soil nutrients as well as grass height than the other treatments applied. Therefore it can be concluded that chopping and resting the veld invaded with P. incana can improve the range and consequently animal production.
- Full Text:
- Date Issued: 2016
Effects of the biocontrol agent, coelocephalapion camarae kissinger, galling on petiole tissues, plant growth and stored reserves in plant parts of two lantana camara L.(verbenaceae) varieties
- Authors: Kistensamy, Yoganambal
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3126 , vital:20372
- Description: The agent evaluated in this study, Coelocephalapion camarae Kissinger (Brentidae), a petiole galling apionid, was released against Lantana camara L. (Verbenaceae) in South Africa and has the potential to significantly contribute to the control of this noxious weed. An important aspect of evaluating the effectiveness of a biocontrol agent; include the understanding of the mechanism in which the biocontrol agent causes damage to the plant and the plant’s response to this damage. Another aspect that was considered in evaluating the effects of the apionid was the varietal differences that exist within the weedy L. camara complex. Larval feeding of C. camarae damaged the tissue in the petioles causing gall formation and this was quantified on two common South African L. camara varieties (017 and 018). Up to 100% of the vascular tissue (xylem and phloem) of effected petioles was eaten by larvae, 25 days after ovipostion in both the L. camara varieties, effectively severing the vascular connection from the leaves. The effect of feeding and galling by different population densities of C. camarae, on biomass and total soluble sugar and starch concentrations of different plant parts was measured on these two varieties during autumn, and compared to a similar study, done during summer. Relatively low galling percentages were achieved in the experiments of this study. Plant growth was less affected by apionid feeding at similar galling levels, as higher galling densities in these trials were similar to those at low exposures in trials by Baars (2002). The dry weights of all individual and combined plant parts for lantana variety 017 was less for both adult density exposures after 70 days compared to the weights of its controls, although not statistically significant at P>0.05 The opposite effect, though barely noticeable was recorded for lantana variety 018; here, the dry weights of individual plant parts and as whole plants weighed more in the plants exposed to both densities of weevil feeding and galling after 70 days, compared to its controls. Coelocephalapion camarae herbivory may thus be more effective in inflicting damage on some L. camara varieties compared to others. The effects of late season carbohydrate storage revealed that, from early- to mid-autumn starch concentrations increased significantly in stems of both L. camara varieties and L. camara var. 018 had larger starch reserves for winter. In L. camara var. 018 stems, starch increased 52 times and concentrations doubled in stems of L. camara var 017. The increase in the sugar and decrease in starch concentrations in leaves of plants of both varieties exposed to apionids in this study was attributed to a possible reduction of available nitrogen and phosphorus, due to apionid feeding, whilst starch was reallocated within the plants to stems and roots. The increase in starch concentrations in stems of plants that were exposed to apionids may have been expected, as compensation for herbivory has been associated with, increases in photosynthetic rates and the mobilization of stored resources. Herbivory by the apionid early in the growing season may be easily compensated for by L. camara as there are nutrient flushes experienced by plants that allows the maximum uptake of nutrients facilitating recovery, whereas later in the season plants suffer lower nutrient availability and don’t recover so readily. Both early and late in the season the accumulated effects of C. camarae feeding over time will undoubtedly decrease fitness of most lantana varieties.
- Full Text:
- Date Issued: 2016
- Authors: Kistensamy, Yoganambal
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3126 , vital:20372
- Description: The agent evaluated in this study, Coelocephalapion camarae Kissinger (Brentidae), a petiole galling apionid, was released against Lantana camara L. (Verbenaceae) in South Africa and has the potential to significantly contribute to the control of this noxious weed. An important aspect of evaluating the effectiveness of a biocontrol agent; include the understanding of the mechanism in which the biocontrol agent causes damage to the plant and the plant’s response to this damage. Another aspect that was considered in evaluating the effects of the apionid was the varietal differences that exist within the weedy L. camara complex. Larval feeding of C. camarae damaged the tissue in the petioles causing gall formation and this was quantified on two common South African L. camara varieties (017 and 018). Up to 100% of the vascular tissue (xylem and phloem) of effected petioles was eaten by larvae, 25 days after ovipostion in both the L. camara varieties, effectively severing the vascular connection from the leaves. The effect of feeding and galling by different population densities of C. camarae, on biomass and total soluble sugar and starch concentrations of different plant parts was measured on these two varieties during autumn, and compared to a similar study, done during summer. Relatively low galling percentages were achieved in the experiments of this study. Plant growth was less affected by apionid feeding at similar galling levels, as higher galling densities in these trials were similar to those at low exposures in trials by Baars (2002). The dry weights of all individual and combined plant parts for lantana variety 017 was less for both adult density exposures after 70 days compared to the weights of its controls, although not statistically significant at P>0.05 The opposite effect, though barely noticeable was recorded for lantana variety 018; here, the dry weights of individual plant parts and as whole plants weighed more in the plants exposed to both densities of weevil feeding and galling after 70 days, compared to its controls. Coelocephalapion camarae herbivory may thus be more effective in inflicting damage on some L. camara varieties compared to others. The effects of late season carbohydrate storage revealed that, from early- to mid-autumn starch concentrations increased significantly in stems of both L. camara varieties and L. camara var. 018 had larger starch reserves for winter. In L. camara var. 018 stems, starch increased 52 times and concentrations doubled in stems of L. camara var 017. The increase in the sugar and decrease in starch concentrations in leaves of plants of both varieties exposed to apionids in this study was attributed to a possible reduction of available nitrogen and phosphorus, due to apionid feeding, whilst starch was reallocated within the plants to stems and roots. The increase in starch concentrations in stems of plants that were exposed to apionids may have been expected, as compensation for herbivory has been associated with, increases in photosynthetic rates and the mobilization of stored resources. Herbivory by the apionid early in the growing season may be easily compensated for by L. camara as there are nutrient flushes experienced by plants that allows the maximum uptake of nutrients facilitating recovery, whereas later in the season plants suffer lower nutrient availability and don’t recover so readily. Both early and late in the season the accumulated effects of C. camarae feeding over time will undoubtedly decrease fitness of most lantana varieties.
- Full Text:
- Date Issued: 2016
Efficiency analysis of electricity distribution by South African Municipalities: a cost frontier approach
- Gqwaka, Aviwe Phelele Sebatian
- Authors: Gqwaka, Aviwe Phelele Sebatian
- Date: 2016
- Subjects: Electric power distribution -- South Africa Public utilities -- South Africa Local government -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/10299 , vital:26650
- Description: Efficiency analysis in the public sector assesses the performance of municipal and government entities in their provision of services to the public. South Africa, in particular, has experienced a large degree of negative feedback with respect to the ability of the government and its municipal departments to provide basic services to citizens. This has led to a number of service delivery protests throughout the country. To remedy this, the ability of the municipality to provide basic services needs to be assessed in order for improvements to be made. A first step in this process would be to determine the efficiency with which municipalities are providing these services. This study focuses on a particular municipal service, namely electricity distribution. Primarily, the efficiency with which municipalities provide electricity to consumers is determined. This is achieved using the parametric cost frontier approach, which is appropriate since municipalities aim to reduce the costs incurred in distributing electricity. The municipalities are compared to a frontier (theoretical best practice) from which inferences on their performances can be made. Those municipalities whose performances are not optimal, deviate from the frontier. The deviations (errors) are then assumed to be caused by two factors, namely stochastic random noise and inefficiency. This composition accounts for effects for which municipalities cannot control (stochastic random noise) and those for which it can (inefficiency). The parametric nature of the cost frontier approach allows for distributional assumptions to be made on these factors. Stochastic random noise is always assumed to be normally distributed, while inefficiency is assumed to be one-sided and positively skewed.
- Full Text:
- Date Issued: 2016
- Authors: Gqwaka, Aviwe Phelele Sebatian
- Date: 2016
- Subjects: Electric power distribution -- South Africa Public utilities -- South Africa Local government -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/10299 , vital:26650
- Description: Efficiency analysis in the public sector assesses the performance of municipal and government entities in their provision of services to the public. South Africa, in particular, has experienced a large degree of negative feedback with respect to the ability of the government and its municipal departments to provide basic services to citizens. This has led to a number of service delivery protests throughout the country. To remedy this, the ability of the municipality to provide basic services needs to be assessed in order for improvements to be made. A first step in this process would be to determine the efficiency with which municipalities are providing these services. This study focuses on a particular municipal service, namely electricity distribution. Primarily, the efficiency with which municipalities provide electricity to consumers is determined. This is achieved using the parametric cost frontier approach, which is appropriate since municipalities aim to reduce the costs incurred in distributing electricity. The municipalities are compared to a frontier (theoretical best practice) from which inferences on their performances can be made. Those municipalities whose performances are not optimal, deviate from the frontier. The deviations (errors) are then assumed to be caused by two factors, namely stochastic random noise and inefficiency. This composition accounts for effects for which municipalities cannot control (stochastic random noise) and those for which it can (inefficiency). The parametric nature of the cost frontier approach allows for distributional assumptions to be made on these factors. Stochastic random noise is always assumed to be normally distributed, while inefficiency is assumed to be one-sided and positively skewed.
- Full Text:
- Date Issued: 2016
Electrode surface modification using iron(II) phthalocyanine immobilized via electrografting and click chemistry and clicked onto azide-functionalized quantum dots: applications in electrocatalysis
- Authors: Nxele, Siphesihle Robin
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3464 , vital:20501
- Description: Tetrakis(5-hexynoxy)Fe(II) phthalocyanine was used alone and in combination with quantum dots (QDs) in order to test the electrocatalytic ability with hydrazine and paraquat as the analytes of interest. This novel phthalocaynine was successfully synthesised and characterized using various characterisation techniques. The QDs used were the well-known core-shell CdSe/ZnS nanostructures. The fabrication of glassy carbon electrodes involved covalent attachment by electrochemical grafting and click chemistry for the first part of the work and the second part involved the conjugation of the synthesised QDs and the phthalocyanine by click chemistry. This approach of conjugating these nanostructures introduced another aspect of novelty to the work reported in this thesis. The immobilisation of this conjugate on a glassy carbon electrode (GCE) was achieved by adsorption. Characterisation techniques such as infrared spectroscopy, x-ray diffractometry, UV/vis spectroscopy, transmission electron microscopy and x-ray photoelectron spectroscopy were used to characterise the molecules and conjugates of interest. With respect to the electrocatalytic part of the work, electrode surface characterisation involved scanning electrochemical microscopy and cyclic voltammetry to determine changes in the nature of the surface as well as reactivity of the surface at different modification steps. Detection limits and the sensitivity determined for the electrocatalysts fabricated here proved to be an improvement compared to other reported work involving phthalocyanines and the test analytes chosen for application. With respect to the conjugate, the electrocatalytic ability was improved when the QDs and phthalocyanine were combined using click chemistry compared to using the phthalocyanine alone.
- Full Text:
- Date Issued: 2016
- Authors: Nxele, Siphesihle Robin
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3464 , vital:20501
- Description: Tetrakis(5-hexynoxy)Fe(II) phthalocyanine was used alone and in combination with quantum dots (QDs) in order to test the electrocatalytic ability with hydrazine and paraquat as the analytes of interest. This novel phthalocaynine was successfully synthesised and characterized using various characterisation techniques. The QDs used were the well-known core-shell CdSe/ZnS nanostructures. The fabrication of glassy carbon electrodes involved covalent attachment by electrochemical grafting and click chemistry for the first part of the work and the second part involved the conjugation of the synthesised QDs and the phthalocyanine by click chemistry. This approach of conjugating these nanostructures introduced another aspect of novelty to the work reported in this thesis. The immobilisation of this conjugate on a glassy carbon electrode (GCE) was achieved by adsorption. Characterisation techniques such as infrared spectroscopy, x-ray diffractometry, UV/vis spectroscopy, transmission electron microscopy and x-ray photoelectron spectroscopy were used to characterise the molecules and conjugates of interest. With respect to the electrocatalytic part of the work, electrode surface characterisation involved scanning electrochemical microscopy and cyclic voltammetry to determine changes in the nature of the surface as well as reactivity of the surface at different modification steps. Detection limits and the sensitivity determined for the electrocatalysts fabricated here proved to be an improvement compared to other reported work involving phthalocyanines and the test analytes chosen for application. With respect to the conjugate, the electrocatalytic ability was improved when the QDs and phthalocyanine were combined using click chemistry compared to using the phthalocyanine alone.
- Full Text:
- Date Issued: 2016
Environmental factors influencing ecotonal changes in an indigenous forest in the Keiskammahoek Forest Estate, Eastern Cape, South Africa
- Authors: Kiva, Luthando
- Date: 2016
- Subjects: Forest ecology -- South Africa -- Eastern Cape Forests and forestry -- South Africa -- Eastern Cape Forest conservation -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2743 , vital:28071
- Description: This study investigates environmental factors influencing ecotonal changes in the Dontsa Forest Management Unit (FMU) of the Keiskammahoek Estate Forest which is located in the Amatole Mountains of the Eastern Cape in the Republic of South Africa. The patterns of forest edge movement were analysed to show trends of forest edge movement from 1975 to 1985, 1975 to 1992, 1975 to 2002, 1975 to 2014, 1985 to 1992, 1985 to 2002, 1985 to 2014, 1992 to 2002, 1992 to 2014 and 2002 to 2014 by digitizing and assessing the scale of forest edge movement using georeferenced aerial photographs. Belt transects were established in six sites that were selected on the basis of physiographic elements for determination of the driving forces of forest ecotonal changes. The results of the study show that the forest edge moved positive towards the grassland biome while in other sites there was contraction of the forest edge from 1975 to 2014. The findings of the study show that some forest patches moved with few individual pioneer species towards the grassland while indigenous species dominated in the ecotone area of the forest in other research sites. D whyteana, A latifolius, R melanophloes, A facultus, R prenoides, C aurea, C bispinosa, C inerme, and S martina are the plant species with high density in the forest ecotone while A latifolius, R prenoides, R melanophloes were highly distributed along the grassland area. The results also show that harvesting of Pinus patula and illegal harvesting of understory species are major factors that result in ecotonal changes of Dontsa FMU. The research sites adjacent to residential areas have experienced reduction of ecotone area as compared to the research sites in high altitude areas of the Amathole Mountains where there is less disturbance. The eastern facing aspect of the forest exhibited a high density of plants in the forest ecotone as compared to the west facing slope.
- Full Text:
- Date Issued: 2016
- Authors: Kiva, Luthando
- Date: 2016
- Subjects: Forest ecology -- South Africa -- Eastern Cape Forests and forestry -- South Africa -- Eastern Cape Forest conservation -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2743 , vital:28071
- Description: This study investigates environmental factors influencing ecotonal changes in the Dontsa Forest Management Unit (FMU) of the Keiskammahoek Estate Forest which is located in the Amatole Mountains of the Eastern Cape in the Republic of South Africa. The patterns of forest edge movement were analysed to show trends of forest edge movement from 1975 to 1985, 1975 to 1992, 1975 to 2002, 1975 to 2014, 1985 to 1992, 1985 to 2002, 1985 to 2014, 1992 to 2002, 1992 to 2014 and 2002 to 2014 by digitizing and assessing the scale of forest edge movement using georeferenced aerial photographs. Belt transects were established in six sites that were selected on the basis of physiographic elements for determination of the driving forces of forest ecotonal changes. The results of the study show that the forest edge moved positive towards the grassland biome while in other sites there was contraction of the forest edge from 1975 to 2014. The findings of the study show that some forest patches moved with few individual pioneer species towards the grassland while indigenous species dominated in the ecotone area of the forest in other research sites. D whyteana, A latifolius, R melanophloes, A facultus, R prenoides, C aurea, C bispinosa, C inerme, and S martina are the plant species with high density in the forest ecotone while A latifolius, R prenoides, R melanophloes were highly distributed along the grassland area. The results also show that harvesting of Pinus patula and illegal harvesting of understory species are major factors that result in ecotonal changes of Dontsa FMU. The research sites adjacent to residential areas have experienced reduction of ecotone area as compared to the research sites in high altitude areas of the Amathole Mountains where there is less disturbance. The eastern facing aspect of the forest exhibited a high density of plants in the forest ecotone as compared to the west facing slope.
- Full Text:
- Date Issued: 2016
Establishing a waste management system for Cape Peninsula University of Technology
- Authors: Myamya, Luyolo Ebenezer
- Date: 2016
- Subjects: Waste minimization -- South Africa Sanitary engineering -- South Africa Environmental management -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/11670 , vital:26949
- Description: Communities around the globe are confronted by environmental challenges such as waste management. These challenges are further aggravated by factors such the increasing volumes of waste, landfills that are running out of capacity and scarcity of suitable land to construct new landfill sites. The National Waste Management Strategy requires participation from all members of society including households, businesses, community organisations, nongovernmental organisations, parastatals and the three spheres of government, to promote practices that minimise the volumes of waste generated. The purpose of the research was to assess and investigate the current waste management practices at the Cape Peninsula University of Technology (CPUT), and recommend a waste management system. The research employed a quantitative approach, where participants were asked to complete a survey questionnaire. A literature review was conducted on waste management at higher learning institutions, with particular focus on the contribution that a university can make in alleviating some of the adverse effects of waste management. The outcome of the review highlighted some of the opportunities and barriers that can either disrupt or augment the process of implementing a waste management system. The results from the research revealed that CPUT does not conform to the hierarchy of waste management, and there is no waste management policy in place. The effect of this is that the stakeholders were not satisfied with the lack of leadership on waste related challenges. By developing a policy, providing leadership, conducting awareness campaigns and prioritising environmental challenges such responsible management waste, could improve the image of the institution in the eyes if its stakeholders.
- Full Text:
- Date Issued: 2016
- Authors: Myamya, Luyolo Ebenezer
- Date: 2016
- Subjects: Waste minimization -- South Africa Sanitary engineering -- South Africa Environmental management -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/11670 , vital:26949
- Description: Communities around the globe are confronted by environmental challenges such as waste management. These challenges are further aggravated by factors such the increasing volumes of waste, landfills that are running out of capacity and scarcity of suitable land to construct new landfill sites. The National Waste Management Strategy requires participation from all members of society including households, businesses, community organisations, nongovernmental organisations, parastatals and the three spheres of government, to promote practices that minimise the volumes of waste generated. The purpose of the research was to assess and investigate the current waste management practices at the Cape Peninsula University of Technology (CPUT), and recommend a waste management system. The research employed a quantitative approach, where participants were asked to complete a survey questionnaire. A literature review was conducted on waste management at higher learning institutions, with particular focus on the contribution that a university can make in alleviating some of the adverse effects of waste management. The outcome of the review highlighted some of the opportunities and barriers that can either disrupt or augment the process of implementing a waste management system. The results from the research revealed that CPUT does not conform to the hierarchy of waste management, and there is no waste management policy in place. The effect of this is that the stakeholders were not satisfied with the lack of leadership on waste related challenges. By developing a policy, providing leadership, conducting awareness campaigns and prioritising environmental challenges such responsible management waste, could improve the image of the institution in the eyes if its stakeholders.
- Full Text:
- Date Issued: 2016
Evaluating farmers' perceptions and the impact of bush encroachment on herbaceous vegetation and soil nutrients in Sheshegu communal rangelands of the Eastern Cape, South Africa
- Authors: Tokozwayo, Sive
- Date: 2016
- Subjects: Range management -- South Africa -- Eastern Cape Brush -- Control -- South Africa -- Eastern Cape Communal rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2733 , vital:28066
- Description: Communal rangelands occupy 13 percent of the agricultural land in South Africa, and these rangelands serve as a source of feed to livestock. These areas are threatened by bush encroachment due to poor rangeland management. This study was conducted in Alice (Sheshegu communal area) and the objective was to assess farmers' perceptions and the impact of bush encroachment on herbaceous vegetation and soil nutrients. Structured questionnaires were used to assess indigenous knowledge of communal farmers on the impact of bush encroachment on rangelands. Fourty (40) respondents from households who owned livestock were randomly selected and interviewed at Sheshegu village. About 89 percent of communal farmers perceived that change of their grasslands to encroached savannas was caused by unreliable rainfall, prolonged drought, and poor rangeland management. Rangeland assessment was performed at four sites (Scattered, Moderate, Mixed and Dense bushland. 100mx50m were demarcated per site, and four 100m transects were laid parallel to each other, 30m apart. The step point method was used to determine both species composition and basal cover. Biomass production was determined by harvesting forage within randomly-paced a 0.25m2 quadrats. Aristada congesta and Eragrostis obtuse were the most dominating grass species in dense, mixed and moderate bushland. Scattered bushland was dominated by Themeda triandra. Biomass production increases with increase in bush density and basal cover improved from winter to summer season. Increaser grass species increase with the increase in bush density, this indicated that the rangeland was poorly managed and palatable species were being replaced by less palatable ones. Species composition of woody plants was determined within a 200m2 belt transect in all sites. Maytenus polycantha, Aloe ferox, Erehia rigida and lucas capensis were the most dominant woody species in Mixed bushland while Acacia karroo was most dominated in Scattered, Moderate and Dense bushland. Woody density showed no significant differences (P> 0.05) between Dense, Mixed and Moderate bushland. Woody plant density in all these sites exceed 2500 plants/ha, which showed that the rangeland was encroached with woody plants. Soil nutrient content was determined for each site. Five samples of soil were collected per site to test the effect of bush encroachment on soil nutrient composition. The concentration of nitrogen and soil pH increased with increase in bush density, while that of potassium, phosphorous, magnesium, sodium and sulphur showed no significant differences (P>0.05) across all homogenous vegetation units. The study revealed that Sheshegu communal farmers are aware of both negative and positive effects of encroachment on their community, and also argue that the government is not willing to support communal farmers in the process of reducing the spread of bush encroachment. It was concluded that the concentration of nitrogen and soil pH increased with increasing bush density and that bush encroachment had negative effects on herbaceous species. It was recommended that communal farmers should be formulating rangeland rules and regulations to manage rangeland resources. Rangeland rules and regulations should be based on the management of livestock management during grazing and harvesting of rangeland resources. The harvesting of woody and good timing of application of fire can also reduce the spread of bush encroachment. Veld resting and rotational grazing can also improve fuel load which is required for burning of woody plants. Furthermore, Department of agriculture should also provide workshops or training to communal farmers use different approaches or cheap ways of reducing bush encroachment and conserving rangeland resources.
- Full Text:
- Date Issued: 2016
- Authors: Tokozwayo, Sive
- Date: 2016
- Subjects: Range management -- South Africa -- Eastern Cape Brush -- Control -- South Africa -- Eastern Cape Communal rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2733 , vital:28066
- Description: Communal rangelands occupy 13 percent of the agricultural land in South Africa, and these rangelands serve as a source of feed to livestock. These areas are threatened by bush encroachment due to poor rangeland management. This study was conducted in Alice (Sheshegu communal area) and the objective was to assess farmers' perceptions and the impact of bush encroachment on herbaceous vegetation and soil nutrients. Structured questionnaires were used to assess indigenous knowledge of communal farmers on the impact of bush encroachment on rangelands. Fourty (40) respondents from households who owned livestock were randomly selected and interviewed at Sheshegu village. About 89 percent of communal farmers perceived that change of their grasslands to encroached savannas was caused by unreliable rainfall, prolonged drought, and poor rangeland management. Rangeland assessment was performed at four sites (Scattered, Moderate, Mixed and Dense bushland. 100mx50m were demarcated per site, and four 100m transects were laid parallel to each other, 30m apart. The step point method was used to determine both species composition and basal cover. Biomass production was determined by harvesting forage within randomly-paced a 0.25m2 quadrats. Aristada congesta and Eragrostis obtuse were the most dominating grass species in dense, mixed and moderate bushland. Scattered bushland was dominated by Themeda triandra. Biomass production increases with increase in bush density and basal cover improved from winter to summer season. Increaser grass species increase with the increase in bush density, this indicated that the rangeland was poorly managed and palatable species were being replaced by less palatable ones. Species composition of woody plants was determined within a 200m2 belt transect in all sites. Maytenus polycantha, Aloe ferox, Erehia rigida and lucas capensis were the most dominant woody species in Mixed bushland while Acacia karroo was most dominated in Scattered, Moderate and Dense bushland. Woody density showed no significant differences (P> 0.05) between Dense, Mixed and Moderate bushland. Woody plant density in all these sites exceed 2500 plants/ha, which showed that the rangeland was encroached with woody plants. Soil nutrient content was determined for each site. Five samples of soil were collected per site to test the effect of bush encroachment on soil nutrient composition. The concentration of nitrogen and soil pH increased with increase in bush density, while that of potassium, phosphorous, magnesium, sodium and sulphur showed no significant differences (P>0.05) across all homogenous vegetation units. The study revealed that Sheshegu communal farmers are aware of both negative and positive effects of encroachment on their community, and also argue that the government is not willing to support communal farmers in the process of reducing the spread of bush encroachment. It was concluded that the concentration of nitrogen and soil pH increased with increasing bush density and that bush encroachment had negative effects on herbaceous species. It was recommended that communal farmers should be formulating rangeland rules and regulations to manage rangeland resources. Rangeland rules and regulations should be based on the management of livestock management during grazing and harvesting of rangeland resources. The harvesting of woody and good timing of application of fire can also reduce the spread of bush encroachment. Veld resting and rotational grazing can also improve fuel load which is required for burning of woody plants. Furthermore, Department of agriculture should also provide workshops or training to communal farmers use different approaches or cheap ways of reducing bush encroachment and conserving rangeland resources.
- Full Text:
- Date Issued: 2016
Evaluating late payment-induced waste in South Africa through lean construction principles
- Authors: Akuffo-Ntow, Eric Ayesu
- Date: 2016
- Subjects: Construction industry -- South Africa -- Finance , Lean manufacturing -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/8867 , vital:26437
- Description: Central to the sustainable and competitive growth of the South African construction industry is a predictable cash flow through on time payment by clients to contractors. However, chronic late payments, a recurring problem in the industry, especially in the public sector, is bringing untold hardship to contractors by derailing their competitiveness and also eroding the trust among the supply chain partners to the extent that some firms end up closing business in the industry. The situation is viewed from the lean construction perspective as an obstacle that is preventing the accrual of the required value to project parties in the construction industry. This research addresses the causes of late payments to contractors and the role of the quantity surveyor (QS) in terms of influencing early payment from a lean construction perspective. A mixed method approach was used for compiling the primary data for the study. Sequentially, one hundred and two (102) quantitative and twelve (12) interview questionnaires were administered to selected contractors and construction professionals working predominantly on public sector projects. The findings revealed that the approval process for evaluation and certification by the client- appointed agent and intermediary institutions is taking longer than contractually allowed, with parties independently undertaking their evaluation prior to the certification date. This is found to be adverse to achieving consensus on the values of the works for authorisation. Other significant barriers are the lack of funds to authorise payment, random auditor general’s documentation changes, lack of administrators’ system integration and capacity to handle cyclical payment processing. Also, contractors have been found to be in default of timeously submitting complete claim documents. It is therefore recommended that the client agents should partner with the contractor in regular design and documentation reviews, arranging the payment process and should also meet jointly to prepare monthly evaluations. In addition, contractors should be mentored from the onset of the project regarding all the necessary documentation and supporting documents that will be required by the client to ensure that payment approvals are not delayed. The payment authori-sation agent’s capacity should be enhanced through training and improved powers as a singular point of control to perform efficiently and their systems and processes should be integrated to ensure that all parties are implementing the same protocols.
- Full Text:
- Date Issued: 2016
- Authors: Akuffo-Ntow, Eric Ayesu
- Date: 2016
- Subjects: Construction industry -- South Africa -- Finance , Lean manufacturing -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/8867 , vital:26437
- Description: Central to the sustainable and competitive growth of the South African construction industry is a predictable cash flow through on time payment by clients to contractors. However, chronic late payments, a recurring problem in the industry, especially in the public sector, is bringing untold hardship to contractors by derailing their competitiveness and also eroding the trust among the supply chain partners to the extent that some firms end up closing business in the industry. The situation is viewed from the lean construction perspective as an obstacle that is preventing the accrual of the required value to project parties in the construction industry. This research addresses the causes of late payments to contractors and the role of the quantity surveyor (QS) in terms of influencing early payment from a lean construction perspective. A mixed method approach was used for compiling the primary data for the study. Sequentially, one hundred and two (102) quantitative and twelve (12) interview questionnaires were administered to selected contractors and construction professionals working predominantly on public sector projects. The findings revealed that the approval process for evaluation and certification by the client- appointed agent and intermediary institutions is taking longer than contractually allowed, with parties independently undertaking their evaluation prior to the certification date. This is found to be adverse to achieving consensus on the values of the works for authorisation. Other significant barriers are the lack of funds to authorise payment, random auditor general’s documentation changes, lack of administrators’ system integration and capacity to handle cyclical payment processing. Also, contractors have been found to be in default of timeously submitting complete claim documents. It is therefore recommended that the client agents should partner with the contractor in regular design and documentation reviews, arranging the payment process and should also meet jointly to prepare monthly evaluations. In addition, contractors should be mentored from the onset of the project regarding all the necessary documentation and supporting documents that will be required by the client to ensure that payment approvals are not delayed. The payment authori-sation agent’s capacity should be enhanced through training and improved powers as a singular point of control to perform efficiently and their systems and processes should be integrated to ensure that all parties are implementing the same protocols.
- Full Text:
- Date Issued: 2016
Evaluation of p-menthane-3, 8-diol citronellal acetal as a suitable bio-plasticizer for polyvinyl chloride
- Authors: Ncanywa, Luphumlo
- Date: 2016
- Subjects: Polyvinyl chloride Chlorine compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/45898 , vital:39317
- Description: The main aim of this project is to test novel naturally-derived plasticizers (bio-plasticizers) synthesized at Innoventon and to determine if they are a suitable replacement for conventional plasticizers used to plasticize polyvinyl chloride. Polyvinyl chloride (PVC) is one of the most common plastics used in the world because of its durability and low cost. PVC when blended with plasticizers is a versatile thermoplastic and is used in many applications. A plasticizer is a substance that is added to a material, usually a polymer, to increase flexibility, softness and workability. Many elastomers and polymers are tough and dry; therefore they need plasticizers to make them useful. A plasticizer must be thoroughly incorporated in the elastomer or polymer in order for it to be effective. There are many types of plasticizers used in the world. Phthalate plasticizers are the most commonly used plasticizers of the past century. They comprise 92% of the global production of plasticizers. DEHP (di-ethyl hexyl phthalate) is the most widely used phthalate plasticizer. Phthalate plasticizers have been proved to be harmful to the environment and human beings. They can cause many harmful diseases to humans e.g. kidney failure, heart disease, liver failure, fertility and growth disorders. They lower testosterone in baby boys that are exposed through breast milk. In light of the above, the use of certain phthalates has been banned in cosmetics and consumer products. Since there is sufficient evidence to raise fears over the use of phthalate plasticizers, there is a great opportunity to find a way to replace phthalate plasticizers in PVC with bio-plasticizers. The current study represents the first step in developing alternative plasticizers for PVC and other polymers. These alternative plasticizers are characterized by low toxicity, low migration and are less harmful to the environment and human beings. p-menthane-3, 8-diol citronellal acetal is one such proposed bio-plasticizer which has a similar structure to the phthalates and has been previously reported by Innoventon to have potential plasticizing characteristics. During this study PVC was plasticized with PMD-citronellal acetal and tested for plasticizing properties. The plasticizing effect of PMD-citronellal acetal in PVC films was compared to that of conventional plasticizer dibutyl phthalate (DBP). The two plasticizers‟ performance was evaluated by preparing PVC films with varying amounts of each plasticizer and PMD-citronellal acetal subjecting the films to a series of tests. Tensile strength and elongation tests were performed on the plasticized and unplasticized films but these tests did not produce consistent results due to premature failures on the films. However, tensile strength was reduced in some films for both plasticizers compared to unplasticized film. Elongation and flexibility were increased in some samples as the percentage of plasticizer in each film was increased. Glass transition temperatures were determined for the plasticized and unplasticized PVC films. Glass transition temperature of both plasticizers was reduced as the percentage of plasticizer in each film was increased. Multiple regression analysis was done on the data to compare the similarity of the two plasticizers. The statistical tests showed that DBP and PMD-citronellal acetal have the same plasticization property with regard to glass transition temperature of PVC. The thermal stability of the PVC films with the two plasticizers was evaluated. Similar thermal stability was observed on the PVC, PVC with DBP and PVC with PMD-citronellal acetal. The leaching of the PMD-citronellal acetal and DBP were compared. The plasticizer loss increased as the percentage of each plasticizer in the PVC increased. The relationship between the percentage of the plasticizers and leaching rate was further analysed using multiple linear regressions. The two plasticizers were found to have the same leaching rate. FTIR analysis was performed on the plasticized and unplasticized PVC films to identify functional groups present and to determine whether the plasticizers formed any bonds with PVC functional groups. The characteristics bands of PVC were observed in FTIR. The FTIR spectra indicated that the plasticizers were incorporated into the PVC matrix without bonding. The results of the tests showed that PMD-citronellal acetal can be a suitable bio-plasticizer for PVC since it exhibited similar plasticization properties to DBP with regard to glass transition temperatures, leaching rates and thermal stability. Regarding tensile strength and elongation, further testing has to be done as the preliminary results were inconclusive. PMDcitronellal acetal was shown to be a possible alternative for DBP.
- Full Text:
- Date Issued: 2016
- Authors: Ncanywa, Luphumlo
- Date: 2016
- Subjects: Polyvinyl chloride Chlorine compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/45898 , vital:39317
- Description: The main aim of this project is to test novel naturally-derived plasticizers (bio-plasticizers) synthesized at Innoventon and to determine if they are a suitable replacement for conventional plasticizers used to plasticize polyvinyl chloride. Polyvinyl chloride (PVC) is one of the most common plastics used in the world because of its durability and low cost. PVC when blended with plasticizers is a versatile thermoplastic and is used in many applications. A plasticizer is a substance that is added to a material, usually a polymer, to increase flexibility, softness and workability. Many elastomers and polymers are tough and dry; therefore they need plasticizers to make them useful. A plasticizer must be thoroughly incorporated in the elastomer or polymer in order for it to be effective. There are many types of plasticizers used in the world. Phthalate plasticizers are the most commonly used plasticizers of the past century. They comprise 92% of the global production of plasticizers. DEHP (di-ethyl hexyl phthalate) is the most widely used phthalate plasticizer. Phthalate plasticizers have been proved to be harmful to the environment and human beings. They can cause many harmful diseases to humans e.g. kidney failure, heart disease, liver failure, fertility and growth disorders. They lower testosterone in baby boys that are exposed through breast milk. In light of the above, the use of certain phthalates has been banned in cosmetics and consumer products. Since there is sufficient evidence to raise fears over the use of phthalate plasticizers, there is a great opportunity to find a way to replace phthalate plasticizers in PVC with bio-plasticizers. The current study represents the first step in developing alternative plasticizers for PVC and other polymers. These alternative plasticizers are characterized by low toxicity, low migration and are less harmful to the environment and human beings. p-menthane-3, 8-diol citronellal acetal is one such proposed bio-plasticizer which has a similar structure to the phthalates and has been previously reported by Innoventon to have potential plasticizing characteristics. During this study PVC was plasticized with PMD-citronellal acetal and tested for plasticizing properties. The plasticizing effect of PMD-citronellal acetal in PVC films was compared to that of conventional plasticizer dibutyl phthalate (DBP). The two plasticizers‟ performance was evaluated by preparing PVC films with varying amounts of each plasticizer and PMD-citronellal acetal subjecting the films to a series of tests. Tensile strength and elongation tests were performed on the plasticized and unplasticized films but these tests did not produce consistent results due to premature failures on the films. However, tensile strength was reduced in some films for both plasticizers compared to unplasticized film. Elongation and flexibility were increased in some samples as the percentage of plasticizer in each film was increased. Glass transition temperatures were determined for the plasticized and unplasticized PVC films. Glass transition temperature of both plasticizers was reduced as the percentage of plasticizer in each film was increased. Multiple regression analysis was done on the data to compare the similarity of the two plasticizers. The statistical tests showed that DBP and PMD-citronellal acetal have the same plasticization property with regard to glass transition temperature of PVC. The thermal stability of the PVC films with the two plasticizers was evaluated. Similar thermal stability was observed on the PVC, PVC with DBP and PVC with PMD-citronellal acetal. The leaching of the PMD-citronellal acetal and DBP were compared. The plasticizer loss increased as the percentage of each plasticizer in the PVC increased. The relationship between the percentage of the plasticizers and leaching rate was further analysed using multiple linear regressions. The two plasticizers were found to have the same leaching rate. FTIR analysis was performed on the plasticized and unplasticized PVC films to identify functional groups present and to determine whether the plasticizers formed any bonds with PVC functional groups. The characteristics bands of PVC were observed in FTIR. The FTIR spectra indicated that the plasticizers were incorporated into the PVC matrix without bonding. The results of the tests showed that PMD-citronellal acetal can be a suitable bio-plasticizer for PVC since it exhibited similar plasticization properties to DBP with regard to glass transition temperatures, leaching rates and thermal stability. Regarding tensile strength and elongation, further testing has to be done as the preliminary results were inconclusive. PMDcitronellal acetal was shown to be a possible alternative for DBP.
- Full Text:
- Date Issued: 2016
Evaluation of physiochemical qualities and heavy metal levels of the final effluents of some wastewater treatment facilities in the Eastern Cape Province of South Africa
- Authors: Kulati, Thanduxolo Cullinan
- Date: 2016
- Subjects: Water -- Purification Sewage -- Purification
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/1547 , vital:27417
- Description: Water is the most abundant substance in nature and vital for life activities. The major water sources for use are surface water bodies such as rivers and lakes, and underground aquifers and pore spaces down the water table (Ring, 2003). Water derived from these sources is not necessarily pure since it contains dissolved inorganic and organic substances, living organisms (viruses, bacteria, etc). For these reasons, water intended for domestic uses should be free from toxic substances and microorganisms that are of health significance (WHO, 2005). The availability and quality of water always have played an important role in determining the quality of life. Water quality is closely linked to water use and to the state of economic development (Chennakrishnan et al., 2008). Ground and surface waters can be contaminated by several sources. In urban areas, the careless disposal of industrial effluents and other wastes may contribute greatly to the poor quality of water (Mathuthu et al., 1997). In most developing countries, most areas are located on the watersheds which are the end points of effluents discharged from various industries (Oberholster and Ashton, 2008). South Africa, as a developing country, is experiencing rapid demographic changes due to urbanization, industrialization and population growth. The country has also been identified as being water-scarce, which can lead to a challenge of meeting the increasing water demand due to industrialization and urbanization. Such population growth increase may result in an increase in wastewater output, especially around urban areas.
- Full Text:
- Date Issued: 2016
- Authors: Kulati, Thanduxolo Cullinan
- Date: 2016
- Subjects: Water -- Purification Sewage -- Purification
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/1547 , vital:27417
- Description: Water is the most abundant substance in nature and vital for life activities. The major water sources for use are surface water bodies such as rivers and lakes, and underground aquifers and pore spaces down the water table (Ring, 2003). Water derived from these sources is not necessarily pure since it contains dissolved inorganic and organic substances, living organisms (viruses, bacteria, etc). For these reasons, water intended for domestic uses should be free from toxic substances and microorganisms that are of health significance (WHO, 2005). The availability and quality of water always have played an important role in determining the quality of life. Water quality is closely linked to water use and to the state of economic development (Chennakrishnan et al., 2008). Ground and surface waters can be contaminated by several sources. In urban areas, the careless disposal of industrial effluents and other wastes may contribute greatly to the poor quality of water (Mathuthu et al., 1997). In most developing countries, most areas are located on the watersheds which are the end points of effluents discharged from various industries (Oberholster and Ashton, 2008). South Africa, as a developing country, is experiencing rapid demographic changes due to urbanization, industrialization and population growth. The country has also been identified as being water-scarce, which can lead to a challenge of meeting the increasing water demand due to industrialization and urbanization. Such population growth increase may result in an increase in wastewater output, especially around urban areas.
- Full Text:
- Date Issued: 2016
Fatty acid composition, colour stability and lipid oxidation of mince produced from fresh and frozen/thawed fallow deer meat
- Authors: Chido, Chakanya
- Date: 2016
- Subjects: Lipids -- Oxidation Meat -- Preservation Mincemeat
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2479 , vital:27874
- Description: The aim of the study was to determine the fatty acid composition, colour stability and lipid oxidation of fresh mince produced from fallow deer and to evaluate the effect of frozen storage duration on the retail display shelf life of the mince. A total of 31 fallow deer carcasses were used in the study. After cooling for 24hrs, the carcasses were deboned, external fat from the fore and hindquarter muscles removed and individually vacuum packed. For the first trial, seven fallow deer carcasses were used. Meat from the hind and fore-quarters of each carcass was divided into two equal batches per animal. One batch was minced (through a 5 mm die) and packed into oxygen permeable overwraps and refrigerated at 4°C for a period of eight days under retail display conditions. The second batch was vacuum packed and frozen at -20°C for 2 months at the end of which mince was also produced and monitored over an eight-day period under the same conditions that were used for the fresh mince. Colour, pH, lipid and myoglobin stability was determined. Proximate and fatty acid composition was also determined. No differences (P>0.05) were noted between proximate composition of fresh and frozen/thawed minced meat. The lipid content of fallow deer was 2.4 percent (±0.04). Total n3 fatty acids differed (P<0.05) between treatments and decreased with increased storage and display day. There were significant (P<0.05) treatment and time interactions on all measured colour parameters, TBARS and myoglobin forms. Fresh mince was lighter and had higher redness (a*) and yellowness (b*) values than mince from two months frozen stored meat. Hue angle for fresh mince remained stable throughout display whereas it increased for frozen/thawed mince. Fresh mince had lower TBARS values than frozen/thawed mince. Minced meat produced from frozen/thawed deer meat had higher surface met-myoglobin and total met-myoglobin percentages. Surface and total oxy-myoglobin percentage was higher in fresh mince. The first trial clearly showed colour and lipid stability differences between fresh mince and mince from frozen/thawed meat. It also showed that fresh mince has a longer retail display life than mince produced from frozen/thawed meat (six days and four days, respectively). In the second trial, the effects of frozen storage duration on colour and lipid stability were investigated. Twenty-four fallow deer were used. Twelve were harvested in June (6male 6female) and the other twelve in August (6 male 6female) of the same year.Twenty four hours after harvesting, the fore and hindquarter muscles of the carcasses were deboned, vacuum packed and kept at -20°C until October (i.e. 2months and 4months frozen storage period). Upon thawing, the meat was processed into mince following the same procedure used for the first trialand displayed for a fiveday period under retail display conditions. Frozen duration and gender had no effect (P>0.05) on the proximate composition of fallow deer meat. The total amount of saturated fatty acids (SFA) increased and total amount of poly unsaturated fatty acids (PUFA) decreased as frozen duration and display day increased (P<0.05). Frozen duration affected (P<0.01) lipid oxidation and percentage oxy-myoglobin. Mince pH and all colour parameters (L*, a*, b*,hue and chroma) differed (P<0.05) between treatments on day zero and three. Display day was a significant factor (P<0.05) on all measured parameters. By day three all parameters except pH showed signs of extended oxidation and discolouration as evidenced by reduced redness, decreased colour intensity and high TBARS values. This study showed that prolonged frozen storage negatively affects the colour and lipid stability of meat and increases oxidation of PUFAs during frozen storage. However, the study also suggests that although frozen/thawed meat has a shorter retail display shelf life; the proximate composition of the meat remains unchanged.
- Full Text:
- Date Issued: 2016
- Authors: Chido, Chakanya
- Date: 2016
- Subjects: Lipids -- Oxidation Meat -- Preservation Mincemeat
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2479 , vital:27874
- Description: The aim of the study was to determine the fatty acid composition, colour stability and lipid oxidation of fresh mince produced from fallow deer and to evaluate the effect of frozen storage duration on the retail display shelf life of the mince. A total of 31 fallow deer carcasses were used in the study. After cooling for 24hrs, the carcasses were deboned, external fat from the fore and hindquarter muscles removed and individually vacuum packed. For the first trial, seven fallow deer carcasses were used. Meat from the hind and fore-quarters of each carcass was divided into two equal batches per animal. One batch was minced (through a 5 mm die) and packed into oxygen permeable overwraps and refrigerated at 4°C for a period of eight days under retail display conditions. The second batch was vacuum packed and frozen at -20°C for 2 months at the end of which mince was also produced and monitored over an eight-day period under the same conditions that were used for the fresh mince. Colour, pH, lipid and myoglobin stability was determined. Proximate and fatty acid composition was also determined. No differences (P>0.05) were noted between proximate composition of fresh and frozen/thawed minced meat. The lipid content of fallow deer was 2.4 percent (±0.04). Total n3 fatty acids differed (P<0.05) between treatments and decreased with increased storage and display day. There were significant (P<0.05) treatment and time interactions on all measured colour parameters, TBARS and myoglobin forms. Fresh mince was lighter and had higher redness (a*) and yellowness (b*) values than mince from two months frozen stored meat. Hue angle for fresh mince remained stable throughout display whereas it increased for frozen/thawed mince. Fresh mince had lower TBARS values than frozen/thawed mince. Minced meat produced from frozen/thawed deer meat had higher surface met-myoglobin and total met-myoglobin percentages. Surface and total oxy-myoglobin percentage was higher in fresh mince. The first trial clearly showed colour and lipid stability differences between fresh mince and mince from frozen/thawed meat. It also showed that fresh mince has a longer retail display life than mince produced from frozen/thawed meat (six days and four days, respectively). In the second trial, the effects of frozen storage duration on colour and lipid stability were investigated. Twenty-four fallow deer were used. Twelve were harvested in June (6male 6female) and the other twelve in August (6 male 6female) of the same year.Twenty four hours after harvesting, the fore and hindquarter muscles of the carcasses were deboned, vacuum packed and kept at -20°C until October (i.e. 2months and 4months frozen storage period). Upon thawing, the meat was processed into mince following the same procedure used for the first trialand displayed for a fiveday period under retail display conditions. Frozen duration and gender had no effect (P>0.05) on the proximate composition of fallow deer meat. The total amount of saturated fatty acids (SFA) increased and total amount of poly unsaturated fatty acids (PUFA) decreased as frozen duration and display day increased (P<0.05). Frozen duration affected (P<0.01) lipid oxidation and percentage oxy-myoglobin. Mince pH and all colour parameters (L*, a*, b*,hue and chroma) differed (P<0.05) between treatments on day zero and three. Display day was a significant factor (P<0.05) on all measured parameters. By day three all parameters except pH showed signs of extended oxidation and discolouration as evidenced by reduced redness, decreased colour intensity and high TBARS values. This study showed that prolonged frozen storage negatively affects the colour and lipid stability of meat and increases oxidation of PUFAs during frozen storage. However, the study also suggests that although frozen/thawed meat has a shorter retail display shelf life; the proximate composition of the meat remains unchanged.
- Full Text:
- Date Issued: 2016
Foraging ecology of the gentoo penguin, pygoscelis papua, at Marion Island
- Authors: Carpenter-Kling, Tegan
- Date: 2016
- Subjects: Gentoo penguin -- Food
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/4912 , vital:20766
- Description: The distribution and subsequent availability of marine predators’ prey is highly variable and is linked to fluctuating oceanographic parameters. It is well documented that annual breeding success of seabirds is related to the temporal availability of prey. Knowledge of a seabird’s diet and at sea distribution is therefore critical in deducing the effect of a fluctuating environment on a seabirds’ population and, furthermore, to understand seabirds role in the environment. The gentoo penguin population at sub-Antarctic Marion Island experienced a decline of 52% between 1994 and 2012. It has been speculated that long term changes in the local marine environment, due to a southward shift of the sub-Antarctic Front (SAF), and subsequent changes in prey availability is the ultimate causal factor. Therefore, this thesis investigates the temporal variation in the diet these birds over three years, through the use of stomach content samples. It then investigates whether the composition of the diet has changed over the long term (approximately 18 years). Additionally, the at sea distribution of these birds was investigated using temperature-depth recorders (TDRs) and global positioning system (GPS) devices. This study represents the first to investigate variation in the diet over three years and over the long term. It is also the first study to track these birds fine scale movement. Over three years, the diet exhibited a high degree of variability. The birds primarily foraged on the fish, Lepidonotothen larseni and the crustaceans, Nauticaris marionis and Euphausia vallentiniy. Over three years, L. larseni became increasingly more important during the breeding season. This was attributed to an increase in availability of these fish during this time, as this time corresponded to the transition of these fish from the larval pelagic phase to the benthic adult phase. Furthermore, the proportions of N. marionis and E. vallentini in the diet varied significantly among years. This variation is possibly a result of the highly variable latitudinal position of the SAF. The diet changed over the long term. There was significantly less N. marionis and more E. vallentini in the diet during more recent years. The long term southward shift of the SAF is considered to be a leading cause of these significant changes in the diet. The shallow inter-island shelf between Marion and Prince Edward Island was an important foraging area possibly due to predictable prey resources. In addition, these birds exhibited an important and possibly unique foraging strategy. They performed short self-maintenance trips where after they return to land to roost for the night. The following day these trips were followed by a longer foraging trip that was followed by chick provisioning. This strategy is unique among seabirds longer trips are associated with self-maintenance and not chick provisioning. This study has provided important knowledge of the foraging ecology of the gentoo penguin at sub-Antarctic Marion Island. It highlights the necessity for continuation of diet and tracking studies of these birds if we are to fully understand the ultimate factors that are causing the decline in their breeding success and population numbers.
- Full Text:
- Date Issued: 2016
- Authors: Carpenter-Kling, Tegan
- Date: 2016
- Subjects: Gentoo penguin -- Food
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/4912 , vital:20766
- Description: The distribution and subsequent availability of marine predators’ prey is highly variable and is linked to fluctuating oceanographic parameters. It is well documented that annual breeding success of seabirds is related to the temporal availability of prey. Knowledge of a seabird’s diet and at sea distribution is therefore critical in deducing the effect of a fluctuating environment on a seabirds’ population and, furthermore, to understand seabirds role in the environment. The gentoo penguin population at sub-Antarctic Marion Island experienced a decline of 52% between 1994 and 2012. It has been speculated that long term changes in the local marine environment, due to a southward shift of the sub-Antarctic Front (SAF), and subsequent changes in prey availability is the ultimate causal factor. Therefore, this thesis investigates the temporal variation in the diet these birds over three years, through the use of stomach content samples. It then investigates whether the composition of the diet has changed over the long term (approximately 18 years). Additionally, the at sea distribution of these birds was investigated using temperature-depth recorders (TDRs) and global positioning system (GPS) devices. This study represents the first to investigate variation in the diet over three years and over the long term. It is also the first study to track these birds fine scale movement. Over three years, the diet exhibited a high degree of variability. The birds primarily foraged on the fish, Lepidonotothen larseni and the crustaceans, Nauticaris marionis and Euphausia vallentiniy. Over three years, L. larseni became increasingly more important during the breeding season. This was attributed to an increase in availability of these fish during this time, as this time corresponded to the transition of these fish from the larval pelagic phase to the benthic adult phase. Furthermore, the proportions of N. marionis and E. vallentini in the diet varied significantly among years. This variation is possibly a result of the highly variable latitudinal position of the SAF. The diet changed over the long term. There was significantly less N. marionis and more E. vallentini in the diet during more recent years. The long term southward shift of the SAF is considered to be a leading cause of these significant changes in the diet. The shallow inter-island shelf between Marion and Prince Edward Island was an important foraging area possibly due to predictable prey resources. In addition, these birds exhibited an important and possibly unique foraging strategy. They performed short self-maintenance trips where after they return to land to roost for the night. The following day these trips were followed by a longer foraging trip that was followed by chick provisioning. This strategy is unique among seabirds longer trips are associated with self-maintenance and not chick provisioning. This study has provided important knowledge of the foraging ecology of the gentoo penguin at sub-Antarctic Marion Island. It highlights the necessity for continuation of diet and tracking studies of these birds if we are to fully understand the ultimate factors that are causing the decline in their breeding success and population numbers.
- Full Text:
- Date Issued: 2016
Formulation development and thermorheological properties of crumb rubber/eva modified bitumen
- Authors: Nare, Keith Dumisani
- Date: 2016
- Subjects: Crumb rubber Bitumen , Vinyl acetate
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/11974 , vital:27015
- Description: The study deals with the formulation development and thermorheological properties of crumb rubber/ethylene vinyl acetate (EVA) modified bitumen with the aim of optimizing the amount of crumb rubber and EVA loadings in bitumen based on thermorheological parameters complex shear modulus, phase angle and rutting parameter. In the modified binders EVA offers plastomer properties whereas the crumb rubber confers elasticity to the bitumen. 13.75% crumb rubber and 2.5% EVA loadings based on aging indices gave the best optimized mixture. The thermorheological behaviour of the best optimized mixture was compared to industrial grade EVA (AP-1) and crumb rubber (AR-1) modified bitumen. Improving aging behaviour of the bitumen was evaluated using four antioxidants: carbon black, hydrated lime, Irganox 1010 and Irgafos 168. The least aging indices at 58˚C and 64˚C were obtained from a 1:1:1 Irganox 1010/hydrated lime/carbon black mixture. SARA (saturates, aromatics, resins and asphaltene) analysis gave the chemical background for application of antioxidants to reduce the propensity of short term aging. To further improve the EVA/crumb rubber optimized mixture for workability FT wax (Sasobit®) was assayed at loadings from 0-2.5%. This was done to match the EVA content and maintain the original maximum loading of 2.5% in the optimized mixture. The phase change abilities of FT wax owing to the high latent heat enabled co-crystallization with the EVA with the elastomeric backbone of crumb rubber acting as support material. The energy-sustainability nexus was found to have worked at less than 1% loading of FT wax in the EVA/crumb rubber modified bitumen. Response surface methodology approach to all the sections of work was used to come up with the optimized mixtures based on rheological parameters complex shear modulus, phase angle and rutting parameter at test temperature 64˚C. The interaction chemistry of bitumen, crumb rubber, EVA and FT wax was found to be first and second order in all cases involving individual contributions and co-interaction amongst the factors. Project costing for each section of work (optimizing section, antioxidant section and FT wax section) was conducted involving the raw materials used, equipment used, labour involved and other costs incurred for all the project work.
- Full Text:
- Date Issued: 2016
- Authors: Nare, Keith Dumisani
- Date: 2016
- Subjects: Crumb rubber Bitumen , Vinyl acetate
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/11974 , vital:27015
- Description: The study deals with the formulation development and thermorheological properties of crumb rubber/ethylene vinyl acetate (EVA) modified bitumen with the aim of optimizing the amount of crumb rubber and EVA loadings in bitumen based on thermorheological parameters complex shear modulus, phase angle and rutting parameter. In the modified binders EVA offers plastomer properties whereas the crumb rubber confers elasticity to the bitumen. 13.75% crumb rubber and 2.5% EVA loadings based on aging indices gave the best optimized mixture. The thermorheological behaviour of the best optimized mixture was compared to industrial grade EVA (AP-1) and crumb rubber (AR-1) modified bitumen. Improving aging behaviour of the bitumen was evaluated using four antioxidants: carbon black, hydrated lime, Irganox 1010 and Irgafos 168. The least aging indices at 58˚C and 64˚C were obtained from a 1:1:1 Irganox 1010/hydrated lime/carbon black mixture. SARA (saturates, aromatics, resins and asphaltene) analysis gave the chemical background for application of antioxidants to reduce the propensity of short term aging. To further improve the EVA/crumb rubber optimized mixture for workability FT wax (Sasobit®) was assayed at loadings from 0-2.5%. This was done to match the EVA content and maintain the original maximum loading of 2.5% in the optimized mixture. The phase change abilities of FT wax owing to the high latent heat enabled co-crystallization with the EVA with the elastomeric backbone of crumb rubber acting as support material. The energy-sustainability nexus was found to have worked at less than 1% loading of FT wax in the EVA/crumb rubber modified bitumen. Response surface methodology approach to all the sections of work was used to come up with the optimized mixtures based on rheological parameters complex shear modulus, phase angle and rutting parameter at test temperature 64˚C. The interaction chemistry of bitumen, crumb rubber, EVA and FT wax was found to be first and second order in all cases involving individual contributions and co-interaction amongst the factors. Project costing for each section of work (optimizing section, antioxidant section and FT wax section) was conducted involving the raw materials used, equipment used, labour involved and other costs incurred for all the project work.
- Full Text:
- Date Issued: 2016
Formulation of an optimal non-targeted liposome preparation for fusion with tumour cell line membranes
- Motala, Ismail Mohammed, Roux, Saartjie
- Authors: Motala, Ismail Mohammed , Roux, Saartjie
- Date: 2016
- Subjects: Liposomes Cancer -- Adjuvant treatment Nanotechnology -- Cancer
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/12220 , vital:27045
- Description: The most common treatment used for cancer is chemotherapy. Chemotherapeutic agents have a greater affinity for rapidly dividing cells which is a characteristic of tumour cells. Although anti-cancer agents have their advantages in providing anti-cancer effects, they can be seen as highly toxic molecules posing a threat to normal healthy tissue within the human body. However, these toxic therapies need to be delivered to tumour sites without damaging healthy tissue. Liposomes can serve as a delivery system for these toxic molecules and be delivered to the tumour site via the EPR effect. Hence, liposomes that fuse with tumour cell line membranes are advantageous in delivering payloads of drugs directly into the tumour cell without damaging normal healthy tissue. The aim of the study was to formulate an optimised liposome preparation in order to enhance cellular uptake by MCF-7, Caco-2 and C3A cancer cell lines via membrane fusion. The optimal liposome formulation was aimed to be prepared utilising a statistical design approach in order to determine the ranges of the parameters that were furthermost optimal in formulating an ideal liposome preparation. The primary screening design was conducted using a 24-1 fractional factorial design that took into account the four parameters that were used to determine the optimisation of the liposomal preparation. The four variables used in the liposome preparation were the phospholipid type (PS or DOPE), the concentration of cholesteryl hemisuccinate (CHEMS) (10 – 40 %), the concentration of PEG2000-PE (0.5 – 4 %) and liposome size (100 or 200 nm). Liposomes were prepared using thin film hydration method and characterisation for size and zeta potential was carried out using photon correlation spectroscopy (PCS). Visual characterisation of liposome size was carried out using atomic force microscopy (AFM). Liposomes were exposed the cancer cell lines with visualisation and uptake being measured using fluorescent microscopy and flow cytometry, respectively. An optimal liposome preparation was prepared following the statistical design method. The optimal liposome preparation consisted of phospholipid type PS, 22.91 % of CHEMS, 4 % of PEG2000-PE and a liposome size of 200 nm. AFM analysis has shown that optimal liposome sizes ranged between 130 and 170 nm. Flow cytometry analysis indicated high level of liposome uptake with actual values falling below the predicted values set out by the statistical design. Fluorescence microscopy captured images of the fluorescent liposomes concentrated on the membrane of cells. The objective of the study was to determine from literature which variables would be desirable in preparing an optimal non-targeted liposome preparation. This was achieved by identifying four such variables and utilising them in a statistical design approach which was screened in order to determine the ideal parameters in preparing the optimised liposome batch. Therefore, from the results obtained it can be concluded that the aim of the study were met by preparing an optimal liposome preparation that has the ability to fuse with the tumour cell line membranes.
- Full Text:
- Date Issued: 2016
- Authors: Motala, Ismail Mohammed , Roux, Saartjie
- Date: 2016
- Subjects: Liposomes Cancer -- Adjuvant treatment Nanotechnology -- Cancer
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/12220 , vital:27045
- Description: The most common treatment used for cancer is chemotherapy. Chemotherapeutic agents have a greater affinity for rapidly dividing cells which is a characteristic of tumour cells. Although anti-cancer agents have their advantages in providing anti-cancer effects, they can be seen as highly toxic molecules posing a threat to normal healthy tissue within the human body. However, these toxic therapies need to be delivered to tumour sites without damaging healthy tissue. Liposomes can serve as a delivery system for these toxic molecules and be delivered to the tumour site via the EPR effect. Hence, liposomes that fuse with tumour cell line membranes are advantageous in delivering payloads of drugs directly into the tumour cell without damaging normal healthy tissue. The aim of the study was to formulate an optimised liposome preparation in order to enhance cellular uptake by MCF-7, Caco-2 and C3A cancer cell lines via membrane fusion. The optimal liposome formulation was aimed to be prepared utilising a statistical design approach in order to determine the ranges of the parameters that were furthermost optimal in formulating an ideal liposome preparation. The primary screening design was conducted using a 24-1 fractional factorial design that took into account the four parameters that were used to determine the optimisation of the liposomal preparation. The four variables used in the liposome preparation were the phospholipid type (PS or DOPE), the concentration of cholesteryl hemisuccinate (CHEMS) (10 – 40 %), the concentration of PEG2000-PE (0.5 – 4 %) and liposome size (100 or 200 nm). Liposomes were prepared using thin film hydration method and characterisation for size and zeta potential was carried out using photon correlation spectroscopy (PCS). Visual characterisation of liposome size was carried out using atomic force microscopy (AFM). Liposomes were exposed the cancer cell lines with visualisation and uptake being measured using fluorescent microscopy and flow cytometry, respectively. An optimal liposome preparation was prepared following the statistical design method. The optimal liposome preparation consisted of phospholipid type PS, 22.91 % of CHEMS, 4 % of PEG2000-PE and a liposome size of 200 nm. AFM analysis has shown that optimal liposome sizes ranged between 130 and 170 nm. Flow cytometry analysis indicated high level of liposome uptake with actual values falling below the predicted values set out by the statistical design. Fluorescence microscopy captured images of the fluorescent liposomes concentrated on the membrane of cells. The objective of the study was to determine from literature which variables would be desirable in preparing an optimal non-targeted liposome preparation. This was achieved by identifying four such variables and utilising them in a statistical design approach which was screened in order to determine the ideal parameters in preparing the optimised liposome batch. Therefore, from the results obtained it can be concluded that the aim of the study were met by preparing an optimal liposome preparation that has the ability to fuse with the tumour cell line membranes.
- Full Text:
- Date Issued: 2016
FRAME: frame routing and manipulation engine
- Authors: Pennefather, Sean Niel
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3608 , vital:20529
- Description: This research reports on the design and implementation of FRAME: an embedded hardware network processing platform designed to perform network frame manipulation and monitoring. This is possible at line speeds compliant with the IEEE 802.3 Ethernet standard. The system provides frame manipulation functionality to aid in the development and implementation of network testing environments. Platform cost and ease of use are both considered during design resulting in fabrication of hardware and the development of Link, a Domain Specific Language used to create custom applications that are compatible with the platform. Functionality of the resulting platform is shown through conformance testing of designed modules and application examples. Throughput testing showed that the peak throughput achievable by the platform is limited to 86.4 Mbit/s, comparable to commodity 100 Mbit hardware and the total cost of the prototype platform ranged between $220 and $254.
- Full Text:
- Date Issued: 2016
- Authors: Pennefather, Sean Niel
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3608 , vital:20529
- Description: This research reports on the design and implementation of FRAME: an embedded hardware network processing platform designed to perform network frame manipulation and monitoring. This is possible at line speeds compliant with the IEEE 802.3 Ethernet standard. The system provides frame manipulation functionality to aid in the development and implementation of network testing environments. Platform cost and ease of use are both considered during design resulting in fabrication of hardware and the development of Link, a Domain Specific Language used to create custom applications that are compatible with the platform. Functionality of the resulting platform is shown through conformance testing of designed modules and application examples. Throughput testing showed that the peak throughput achievable by the platform is limited to 86.4 Mbit/s, comparable to commodity 100 Mbit hardware and the total cost of the prototype platform ranged between $220 and $254.
- Full Text:
- Date Issued: 2016
Genetic and biological characterisation of a novel South African Cydia pomonella granulovirus (CpGV-SA) isolate
- Motsoeneng, Boitumelo Madika
- Authors: Motsoeneng, Boitumelo Madika
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:20503 , http://hdl.handle.net/10962/d1021266
- Description: The codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is the primary pest of pome fruit cultivated worldwide. The control of this insect pest has been dependent on the frequent use of broad-spectrum chemical pesticides, which has led to the development of resistance in pest populations and negative effects on human health and the environment. The Betabaculovirus of C. pomonella has successfully been applied as a biological control agent in integrated pest management (IPM) programmes for the suppression of pest populations worldwide. Previously, all Cydia pomonella granulovirus (CpGV) biopesticides were based on a Mexican isolate (CpGV-M) and although these products are highly efficient at controlling C. pomonella, resistance cases have been reported across Europe. The identification of novel CpGV isolates as additional or alternative control agents to manage resistance is therefore necessary. This study aimed to genetically and biologically characterise a novel South African C. pomonella granulovirus isolate and to test its virulence against neonate larvae. Based on the morphology of the occlusion bodies observed using transmission electron microscopy, granuloviruses were recovered from diseased and dead larvae collected from an orchard in South Africa where no virus applications had been made. DNA was extracted and the identification of the isolated granulovirus was achieved through the PCR amplification and sequencing of the lef-8, lef-9, granulin and egt genes. Submission of the gene sequences to BLAST revealed high percentage identities to sequences from various CpGV isolates, resulting in the naming of the isolate in this study as the South African Cydia pomonella granulovirus (CpGV-SA) isolate. Phylogenetic analysis based on the single nucleotide polymorphisms (SNPs) detected in the lef-8, lef-9 and granulin nucleotide sequences grouped the South African isolate with CpGV-E2 (genome type B) and CpGV-S (genome type E). The CpGV-SA isolate was further genetically characterised by restriction endonuclease analysis and complete sequencing of the genomic DNA. Differences were observed for the BamHI, EcoRI, PstI and XhoI profiles of CpGV-SA in comparison to the respective profiles generated for CpGV-M extracted from a biopesticide, Carpovirusine® (Arysta Lifescience, France). Several genetic variations between the complete genome sequence of CpGV-SA and the reference isolate, CpGV-M1, as well as a recent genome submission of CpGV-M, both representing genome type A were observed. The complete genome analysis confirmed that CpGV-SA is genetically different from the Mexican CpGV isolate, used in thedevelopment of most biopesticides. In silico restriction profiles of the genome sequence obtained for CpGV-SA and genome sequences of genetically different CpGV isolates originating from Mexico (M1 and M), England (E2), Canada (S) and Iran (I12 and I07), available on the NCBI’s GenBank database confirmed that CpGV-SA is of mixed genotypes. Furthermore, the South African isolate shared the single common difference found in the pe38 gene of resistance overcoming isolates, which was the absence of an internal 24 nucleotide repeat present in CpGV-M1. In addition to the common difference, SNPs detected in the pe38 gene grouped the isolate with the CpGV-S isolate, suggesting that the CpGV-SA isolate is predominantly of genome type E. To determine the biological activity of CpGV-SA against neonate C. pomonella larvae, surface bioassays were conducted alongside CpGV-M (Carpovirusine®) bioassays. The LC50 and LC90 values for the South African isolate were 1.6 × 103 and 1.2 × 105 OBs/ml respectively. The LT50 was determined to be 135 hours. These values were similar to the values obtained for CpGV-M (Carpovirusine®). The results in this study suggest that a novel South African CpGV isolate of mixed genotypes, potentially able to overcome resistance in C. pomonella, with biological activity similar to CpGV-M (Carpovirusine®) and important for the control of C. pomonella was recovered. The CpGV-SA isolate could therefore potentially be developed into a biopesticide for use in resistance management strategies against C. pomonella populations in South Africa.
- Full Text:
- Date Issued: 2016
- Authors: Motsoeneng, Boitumelo Madika
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:20503 , http://hdl.handle.net/10962/d1021266
- Description: The codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is the primary pest of pome fruit cultivated worldwide. The control of this insect pest has been dependent on the frequent use of broad-spectrum chemical pesticides, which has led to the development of resistance in pest populations and negative effects on human health and the environment. The Betabaculovirus of C. pomonella has successfully been applied as a biological control agent in integrated pest management (IPM) programmes for the suppression of pest populations worldwide. Previously, all Cydia pomonella granulovirus (CpGV) biopesticides were based on a Mexican isolate (CpGV-M) and although these products are highly efficient at controlling C. pomonella, resistance cases have been reported across Europe. The identification of novel CpGV isolates as additional or alternative control agents to manage resistance is therefore necessary. This study aimed to genetically and biologically characterise a novel South African C. pomonella granulovirus isolate and to test its virulence against neonate larvae. Based on the morphology of the occlusion bodies observed using transmission electron microscopy, granuloviruses were recovered from diseased and dead larvae collected from an orchard in South Africa where no virus applications had been made. DNA was extracted and the identification of the isolated granulovirus was achieved through the PCR amplification and sequencing of the lef-8, lef-9, granulin and egt genes. Submission of the gene sequences to BLAST revealed high percentage identities to sequences from various CpGV isolates, resulting in the naming of the isolate in this study as the South African Cydia pomonella granulovirus (CpGV-SA) isolate. Phylogenetic analysis based on the single nucleotide polymorphisms (SNPs) detected in the lef-8, lef-9 and granulin nucleotide sequences grouped the South African isolate with CpGV-E2 (genome type B) and CpGV-S (genome type E). The CpGV-SA isolate was further genetically characterised by restriction endonuclease analysis and complete sequencing of the genomic DNA. Differences were observed for the BamHI, EcoRI, PstI and XhoI profiles of CpGV-SA in comparison to the respective profiles generated for CpGV-M extracted from a biopesticide, Carpovirusine® (Arysta Lifescience, France). Several genetic variations between the complete genome sequence of CpGV-SA and the reference isolate, CpGV-M1, as well as a recent genome submission of CpGV-M, both representing genome type A were observed. The complete genome analysis confirmed that CpGV-SA is genetically different from the Mexican CpGV isolate, used in thedevelopment of most biopesticides. In silico restriction profiles of the genome sequence obtained for CpGV-SA and genome sequences of genetically different CpGV isolates originating from Mexico (M1 and M), England (E2), Canada (S) and Iran (I12 and I07), available on the NCBI’s GenBank database confirmed that CpGV-SA is of mixed genotypes. Furthermore, the South African isolate shared the single common difference found in the pe38 gene of resistance overcoming isolates, which was the absence of an internal 24 nucleotide repeat present in CpGV-M1. In addition to the common difference, SNPs detected in the pe38 gene grouped the isolate with the CpGV-S isolate, suggesting that the CpGV-SA isolate is predominantly of genome type E. To determine the biological activity of CpGV-SA against neonate C. pomonella larvae, surface bioassays were conducted alongside CpGV-M (Carpovirusine®) bioassays. The LC50 and LC90 values for the South African isolate were 1.6 × 103 and 1.2 × 105 OBs/ml respectively. The LT50 was determined to be 135 hours. These values were similar to the values obtained for CpGV-M (Carpovirusine®). The results in this study suggest that a novel South African CpGV isolate of mixed genotypes, potentially able to overcome resistance in C. pomonella, with biological activity similar to CpGV-M (Carpovirusine®) and important for the control of C. pomonella was recovered. The CpGV-SA isolate could therefore potentially be developed into a biopesticide for use in resistance management strategies against C. pomonella populations in South Africa.
- Full Text:
- Date Issued: 2016
Genetic structure and biogeography of three wrasse species (Labridae) within the Western Indian Ocean
- Authors: Mayekiso, Sisanda
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/1114 , vital:20021
- Description: The biogeography of wrasses within the Western Indian Ocean (WIO) is poorly understood, with regard to origins and genetic differentiation or connectivity among the regions of the WIO. This region is a good model for studying the influence of physical complexities and biogeographic breaks in shaping patterns of differentiation in wrasses. Three reef-associated fish species, Cheilio inermis, Thalassoma hebraicum and T. lunare, were selected to examine the factors that have influenced patterns of differentiation across the WIO. Each species was sampled from various localities of the WIO, the Red Sea and Indo-West Pacific Islands. Sequence data were generated from two mitochondrial gene fragments (cytochrome b and ATPase 6) and one nuclear locus (the first intron of the ribosomal protein S7 gene). Genetic analyses were used to calculate genetic diversity indices within species, which were then compared among species. The relationships among haplotypes and alleles were constructed using median-joining networks. Where necessary, neighbour-joining trees (NJ) were constructed to examine relationships among haplotypes and alleles for the Thalassoma species. Population structure was analysed using AMOVA and pairwise ФST to compare and calculate differentiation between the WIO localities. Mismatch distributions were used to examine population growth and decline or stability, and demographic parameters were used to calculate time of population expansion. There was high haplotype (h = 0.88 to 0.98) and low nucleotide diversities (π = 0.003 to 0.008) among all species for mitochondrial markers. For S7 intron I, high allelic (A = 0.95 to 0.98) and low nucleotide diversities (π = 0.002 to 0.014) were observed for all species. The pairwise ФST values revealed little to great (ФST = -0.02 to 0.67) genetic differentiation between localities, across all species for the three gene regions. The pairwise comparisons indicated the differentiation in C. inermis of Tanzania and Kenya from Mozambique and Nosy Be (Madagascar). The widespread C. inermis also revealed the differentiation of Kenya and Tanzania. For C. inermis, the AMOVAs of ATPase 6 and cytochrome b data indicated high differentiation among defined locality groups. The groups were defined according to geographic proximity. However, the AMOVA of the nuclear gene (S7 intron I) did not find variation among defined locality groups. Cheilio inermis revealed a sequence divergence of 0.4%. The divergence that was found in C. inermis was not enough to suggest a cryptic species within the WIO. Overall, the widespread and monotypic C. inermis revealed genetic differentiation within the WIO. Thalassoma hebraicum generally revealed little genetic differentiation across the WIO. The AMOVAs of the three gene regions showed no variation among specimens of the defined locality groups. However, some differentiation was found between localities. The pairwise comparisons of T. hebraicum revealed the differentiation of Seychelles from the African mainland and Madagascar. Southern Africa was observed to be differentiated from Nosy Be and Zanzibar. The observed differentiation could be caused by oceanic barriers such as the South Equatorial Current (SEQC), East African Coastal Current (EACC), and the Comoros Gyres and eddies in the Mozambique Channel, and Agulhas Current. Thalassoma lunare revealed genetic isolation between the WIO and the Red Sea as well as within the WIO. The genetic isolation between the WIO and the Red Sea is probably due to the historical isolation by the Bab al Mandab and contemporary barriers such as the cold upwelling cells in Somalia. The differentiation of Maldives from the African mainland and Seychelles could be due to distance and the upwelling cells created by monsoon winds. Mismatch distributions suggested that C. inermis and T. hebraicum had undergone demographic expansion during the Pleistocene (92 678 to 40 219 years ago). The results of the current study are similar to those from previous studies of WIO reef fish species, and the results of the present study could have potential implications for conservation and fisheries management. Single genetic markers and single species studies do not detect all barriers to dispersal in the WIO, thus they are insufficient to inform conservation management. Thus, the use of multispecies and genetic markers in the current study can be adopted by other studies of the marine taxa of the WIO.
- Full Text:
- Date Issued: 2016
- Authors: Mayekiso, Sisanda
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/1114 , vital:20021
- Description: The biogeography of wrasses within the Western Indian Ocean (WIO) is poorly understood, with regard to origins and genetic differentiation or connectivity among the regions of the WIO. This region is a good model for studying the influence of physical complexities and biogeographic breaks in shaping patterns of differentiation in wrasses. Three reef-associated fish species, Cheilio inermis, Thalassoma hebraicum and T. lunare, were selected to examine the factors that have influenced patterns of differentiation across the WIO. Each species was sampled from various localities of the WIO, the Red Sea and Indo-West Pacific Islands. Sequence data were generated from two mitochondrial gene fragments (cytochrome b and ATPase 6) and one nuclear locus (the first intron of the ribosomal protein S7 gene). Genetic analyses were used to calculate genetic diversity indices within species, which were then compared among species. The relationships among haplotypes and alleles were constructed using median-joining networks. Where necessary, neighbour-joining trees (NJ) were constructed to examine relationships among haplotypes and alleles for the Thalassoma species. Population structure was analysed using AMOVA and pairwise ФST to compare and calculate differentiation between the WIO localities. Mismatch distributions were used to examine population growth and decline or stability, and demographic parameters were used to calculate time of population expansion. There was high haplotype (h = 0.88 to 0.98) and low nucleotide diversities (π = 0.003 to 0.008) among all species for mitochondrial markers. For S7 intron I, high allelic (A = 0.95 to 0.98) and low nucleotide diversities (π = 0.002 to 0.014) were observed for all species. The pairwise ФST values revealed little to great (ФST = -0.02 to 0.67) genetic differentiation between localities, across all species for the three gene regions. The pairwise comparisons indicated the differentiation in C. inermis of Tanzania and Kenya from Mozambique and Nosy Be (Madagascar). The widespread C. inermis also revealed the differentiation of Kenya and Tanzania. For C. inermis, the AMOVAs of ATPase 6 and cytochrome b data indicated high differentiation among defined locality groups. The groups were defined according to geographic proximity. However, the AMOVA of the nuclear gene (S7 intron I) did not find variation among defined locality groups. Cheilio inermis revealed a sequence divergence of 0.4%. The divergence that was found in C. inermis was not enough to suggest a cryptic species within the WIO. Overall, the widespread and monotypic C. inermis revealed genetic differentiation within the WIO. Thalassoma hebraicum generally revealed little genetic differentiation across the WIO. The AMOVAs of the three gene regions showed no variation among specimens of the defined locality groups. However, some differentiation was found between localities. The pairwise comparisons of T. hebraicum revealed the differentiation of Seychelles from the African mainland and Madagascar. Southern Africa was observed to be differentiated from Nosy Be and Zanzibar. The observed differentiation could be caused by oceanic barriers such as the South Equatorial Current (SEQC), East African Coastal Current (EACC), and the Comoros Gyres and eddies in the Mozambique Channel, and Agulhas Current. Thalassoma lunare revealed genetic isolation between the WIO and the Red Sea as well as within the WIO. The genetic isolation between the WIO and the Red Sea is probably due to the historical isolation by the Bab al Mandab and contemporary barriers such as the cold upwelling cells in Somalia. The differentiation of Maldives from the African mainland and Seychelles could be due to distance and the upwelling cells created by monsoon winds. Mismatch distributions suggested that C. inermis and T. hebraicum had undergone demographic expansion during the Pleistocene (92 678 to 40 219 years ago). The results of the current study are similar to those from previous studies of WIO reef fish species, and the results of the present study could have potential implications for conservation and fisheries management. Single genetic markers and single species studies do not detect all barriers to dispersal in the WIO, thus they are insufficient to inform conservation management. Thus, the use of multispecies and genetic markers in the current study can be adopted by other studies of the marine taxa of the WIO.
- Full Text:
- Date Issued: 2016
Genotypic and phenotypic characterization of enterococci from cow dung and environmental water sources in three selected dairy farms in Amathole District
- Authors: Tanih, Godfred Ngu
- Date: 2016
- Subjects: Enterobacteriaceae Water -- Microbiology Enterococcus faecalis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2348 , vital:27755
- Description: Enterococcus species are integral members of the gastrointestinal microfloral of humans, animals, birds, as well as insects. Their presence in water and food has been greatly associated with faecal contamination. This study was aimed at evaluating the incidence of Enterococcus species in cow dung and environmental water sources in three commercial dairy farms. In addition, their antibiotic profiles were determined as well as resistance and virulence genes. Furthermore, the genetic relatedness of the isolates was determined by molecular typing method (RAPD PCR). Three hundred and thirty four water and faecal samples consisting of 117, 116 and 101 were collected from Seven Star Middle Drift and Fort Hare Dairy trusts respectively. Of the 334 samples collected, 289 were of faecal origin and 45 from water sources within the farms. All samples were screened for enterococci using culture base growth media and molecular methods targeting the tuf gene. Speciation was done using species-specific primers and the incidences of various species within the farms determined. Furthermore resistance to antibiotics and multidrug-resistant phenotypes were established using the disk diffusion method. Genes coding for virulence and resistance were also determined. From the samples collected, 313 (289 faecal and 24 water) presumptive enteroccocci were isolated, 305 of 313 (97.45 percent) were confirmed as Enterococcus of which 239 of 305 (78.38 percent) were identified as E. hirae, 15 of 305 (4.92 percent) as E. faecium, 12/305 (3.93 percent) as E. durans, 6 of 305 (1.97 percent) as E. faecalis and 33 of 305 (10.82 percent) were unidentified. Out of the five virulence genes that were targeted in the study only gelE (71.80 percent of 219/305) and ace (27.2 percent 83/305) were present in the isolates. Phenotypic resistance to antibiotics was observed is in all twelve antibiotics tested with multidrug resistance phenotypes detected in some enterococcal isolates most predominant in Seven Star and Middledrift dairy trust. Finally RAPD profiles of the isolates showed high relatedness between the strains from water and cow dung sources in all three commercial dairy farms suggesting possible contamination from cow dung to the water sources or vice versa.
- Full Text:
- Date Issued: 2016
- Authors: Tanih, Godfred Ngu
- Date: 2016
- Subjects: Enterobacteriaceae Water -- Microbiology Enterococcus faecalis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2348 , vital:27755
- Description: Enterococcus species are integral members of the gastrointestinal microfloral of humans, animals, birds, as well as insects. Their presence in water and food has been greatly associated with faecal contamination. This study was aimed at evaluating the incidence of Enterococcus species in cow dung and environmental water sources in three commercial dairy farms. In addition, their antibiotic profiles were determined as well as resistance and virulence genes. Furthermore, the genetic relatedness of the isolates was determined by molecular typing method (RAPD PCR). Three hundred and thirty four water and faecal samples consisting of 117, 116 and 101 were collected from Seven Star Middle Drift and Fort Hare Dairy trusts respectively. Of the 334 samples collected, 289 were of faecal origin and 45 from water sources within the farms. All samples were screened for enterococci using culture base growth media and molecular methods targeting the tuf gene. Speciation was done using species-specific primers and the incidences of various species within the farms determined. Furthermore resistance to antibiotics and multidrug-resistant phenotypes were established using the disk diffusion method. Genes coding for virulence and resistance were also determined. From the samples collected, 313 (289 faecal and 24 water) presumptive enteroccocci were isolated, 305 of 313 (97.45 percent) were confirmed as Enterococcus of which 239 of 305 (78.38 percent) were identified as E. hirae, 15 of 305 (4.92 percent) as E. faecium, 12/305 (3.93 percent) as E. durans, 6 of 305 (1.97 percent) as E. faecalis and 33 of 305 (10.82 percent) were unidentified. Out of the five virulence genes that were targeted in the study only gelE (71.80 percent of 219/305) and ace (27.2 percent 83/305) were present in the isolates. Phenotypic resistance to antibiotics was observed is in all twelve antibiotics tested with multidrug resistance phenotypes detected in some enterococcal isolates most predominant in Seven Star and Middledrift dairy trust. Finally RAPD profiles of the isolates showed high relatedness between the strains from water and cow dung sources in all three commercial dairy farms suggesting possible contamination from cow dung to the water sources or vice versa.
- Full Text:
- Date Issued: 2016