A standardised protocol for roadkill detection and the determinants of roadkill in the greater Mapungubwe Transfrontier Conservation Area, Limpopo Province, South Africa
- Authors: Collinson, Wendy Jane
- Date: 2013
- Subjects: Roadkill -- South Africa -- Mapungubwe Site , Traffic safety and wildlife -- South Africa -- Mapungubwe Site
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5606 , http://hdl.handle.net/10962/d1002056 , Roadkill -- South Africa -- Mapungubwe Site , Traffic safety and wildlife -- South Africa -- Mapungubwe Site
- Description: Despite evidence suggesting that road traffic is a major threat to biodiversity loss, very little is known about its actual impact on wildlife populations in South Africa. Globally, road density and traffic volumes are increasing, and although huge budgets are devoted to the construction and upgrading of roads, there is little or no allocation to mitigation measures for protecting fauna in most countries, particularly Africa. Further, no global standardised protocol exists for the rapid assessment of roadkill or the most economical and efficient approach for assessing roadkill rates. Using vehicle field trials, the reliability of detecting artificially deployed roadkill was assessed. Roadkill detection rates decreased significantly at speeds >50 km/h and were also significantly influenced by light conditions (i.e. detection success was greater when the sun was high) and the position of the roadkill on the road (i.e. smaller roadkill on verges were often missed). These results suggest that roadkill sampling was most effective between 1.5 hours after dawn and 1.5 hours before dusk and that driving at slower speeds (<50 km.h⁻ₑ) was required to detect roadkill. This protocol was implemented across three ecological seasons on a 100 km paved road and a 20 km unpaved road in the Greater Mapungubwe Transfrontier Conservation Area, Limpopo Province, South Africa. Driven daily over a 120-day period (three periods consisting each of 40 days), a total of 1,027 roadkill were recorded. These comprised 162 species from all terrestrial vertebrate groups with birds being the most commonly encountered roadkill (50% of all incidents). The high numbers of vertebrates identified as roadkill suggests that road traffic could have potentially unsustainable impacts on wildlife populations and hence the biodiversity of the area. Seventeen variables were identified as possible determinants of roadkill occurrence with season, rainfall, minimum and maximum temperature, habitat type, grass height, grass density, fence type and vehicle type significantly influencing roadkill numbers. Significantly more roadkill were detected on the paved road (9.91/100km) than on the unpaved road (1.8/100km) probably because of greater traffic volumes and the increased speed that vehicles travelled on the paved road. Warmer temperatures and increased rainfall in the preceding 24 hours also increased road mortality numbers as animals tended to become more active during these times. Interestingly, more roadkill was detected in open roadside habitats compared to dense roadside habitats on both the paved and unpaved roads and when grass on the roadside verge was of intermediate height. Open habitat possibly may provide a natural corridor for wildlife which ultimately end up on the road. Roadkill numbers increased when certain other physical barriers, such as cattle fences, were present, probably because these barriers were more penetrable than electric fencing. A series of mitigation measures are proposed to reduce the impacts of roads on wildlife in South Africa. These mitigation measures highlight the need to address the balance between the development of a country’s transport infrastructure and the conservation of its fauna. It is important that research on the impacts of roads becomes standardised to enable robust statistical comparisons which will provide a greater understanding of the potential threats to vertebrate biodiversity
- Full Text:
- Date Issued: 2013
- Authors: Collinson, Wendy Jane
- Date: 2013
- Subjects: Roadkill -- South Africa -- Mapungubwe Site , Traffic safety and wildlife -- South Africa -- Mapungubwe Site
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5606 , http://hdl.handle.net/10962/d1002056 , Roadkill -- South Africa -- Mapungubwe Site , Traffic safety and wildlife -- South Africa -- Mapungubwe Site
- Description: Despite evidence suggesting that road traffic is a major threat to biodiversity loss, very little is known about its actual impact on wildlife populations in South Africa. Globally, road density and traffic volumes are increasing, and although huge budgets are devoted to the construction and upgrading of roads, there is little or no allocation to mitigation measures for protecting fauna in most countries, particularly Africa. Further, no global standardised protocol exists for the rapid assessment of roadkill or the most economical and efficient approach for assessing roadkill rates. Using vehicle field trials, the reliability of detecting artificially deployed roadkill was assessed. Roadkill detection rates decreased significantly at speeds >50 km/h and were also significantly influenced by light conditions (i.e. detection success was greater when the sun was high) and the position of the roadkill on the road (i.e. smaller roadkill on verges were often missed). These results suggest that roadkill sampling was most effective between 1.5 hours after dawn and 1.5 hours before dusk and that driving at slower speeds (<50 km.h⁻ₑ) was required to detect roadkill. This protocol was implemented across three ecological seasons on a 100 km paved road and a 20 km unpaved road in the Greater Mapungubwe Transfrontier Conservation Area, Limpopo Province, South Africa. Driven daily over a 120-day period (three periods consisting each of 40 days), a total of 1,027 roadkill were recorded. These comprised 162 species from all terrestrial vertebrate groups with birds being the most commonly encountered roadkill (50% of all incidents). The high numbers of vertebrates identified as roadkill suggests that road traffic could have potentially unsustainable impacts on wildlife populations and hence the biodiversity of the area. Seventeen variables were identified as possible determinants of roadkill occurrence with season, rainfall, minimum and maximum temperature, habitat type, grass height, grass density, fence type and vehicle type significantly influencing roadkill numbers. Significantly more roadkill were detected on the paved road (9.91/100km) than on the unpaved road (1.8/100km) probably because of greater traffic volumes and the increased speed that vehicles travelled on the paved road. Warmer temperatures and increased rainfall in the preceding 24 hours also increased road mortality numbers as animals tended to become more active during these times. Interestingly, more roadkill was detected in open roadside habitats compared to dense roadside habitats on both the paved and unpaved roads and when grass on the roadside verge was of intermediate height. Open habitat possibly may provide a natural corridor for wildlife which ultimately end up on the road. Roadkill numbers increased when certain other physical barriers, such as cattle fences, were present, probably because these barriers were more penetrable than electric fencing. A series of mitigation measures are proposed to reduce the impacts of roads on wildlife in South Africa. These mitigation measures highlight the need to address the balance between the development of a country’s transport infrastructure and the conservation of its fauna. It is important that research on the impacts of roads becomes standardised to enable robust statistical comparisons which will provide a greater understanding of the potential threats to vertebrate biodiversity
- Full Text:
- Date Issued: 2013
The redemptive life story of Glenda Watson-Kahlenberg: a psychobiography
- Authors: Connelly, Ruth Ellen
- Date: 2013
- Subjects: Watson-Kahlenberg, Glenda -- Psychology , Redemption , Meaning (Psychology) , Well-being , Forgiveness
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9956 , http://hdl.handle.net/10948/d1019690
- Description: This psychobiography is focused on the life of Glenda Watson-Kahlenberg, whose life history epitomises the redemptive theme of triumph over tragedy. A phenomenological approach to the study allowed the researcher to observe the participant‟s lived experience through the theoretical lens of Frankl‟s conceptualization of a meaningful and full existence. A holistic perspective of factors contributing to redemption was accommodated by the Biopsychosocial-spiritual Model. The aim of this longitudinal revelatory study was to illuminate the process of redemption in a life, which leads to restoration and wholeness. This study breaks with traditional psychobiography – in that a life in progress has been selected; and personality development is not the key focus. This psychobiographical undertaking was anchored in qualitative research in the form of a single case study. Four types of triangulation were utilized, namely: data, investigators, theory and methodological triangulation. In addition, Alexander‟s identifiers of saliency, Miles and Huberman‟s data-management guidelines, Schultz‟s prototypical scenes, and Guba‟s criteria for trustworthiness, guided the methodology to ensure reliable data extraction and interpretation. The present researcher was in search of a deeper understanding of the enabling factors facilitating a restorative process in a life that was challenged by setbacks. Given the increasing pressures facing individuals in this modern era, the redemptive theme holds particular relevance, and was graphically demonstrated in the life of the participant who experienced trauma, widowhood, divorce, single parenthood, and a spate of medical and psychological setbacks. The findings suggest that the mental health clinician‟s utilisation of Frankl‟s conceptualisation of meaning in the most challenging circumstances, proffers itself as an all-purpose life-tool which enables individuals to overcome their challenges. The study demonstrated that gaining meaning in life is inextricably tied to an implicit legacy-oriented worldview. Of significance, is the role of forgiveness which emerged as the central redemptive catalyst. In this study, the resolution of past hurts through forgiveness, and the search for meaning, merge, forming an arterial theme in the life story of the participant. The dual impact of these factors not only reversed contaminated life-scripts, it also birthed a new calling in life which set the participant on a generative life course. The findings related to a redemptive life not only confirms existing theory, but also adds perspectives not previously considered. In addition, the findings related to the role of forgiveness has positive implications for the individual‟s physical and psychological wellbeing. Greater intentionality on the part of therapists to thread forgiveness into their practice, remains invitational in the light of the eugraphic impact demonstrated in this study.
- Full Text:
- Date Issued: 2013
- Authors: Connelly, Ruth Ellen
- Date: 2013
- Subjects: Watson-Kahlenberg, Glenda -- Psychology , Redemption , Meaning (Psychology) , Well-being , Forgiveness
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9956 , http://hdl.handle.net/10948/d1019690
- Description: This psychobiography is focused on the life of Glenda Watson-Kahlenberg, whose life history epitomises the redemptive theme of triumph over tragedy. A phenomenological approach to the study allowed the researcher to observe the participant‟s lived experience through the theoretical lens of Frankl‟s conceptualization of a meaningful and full existence. A holistic perspective of factors contributing to redemption was accommodated by the Biopsychosocial-spiritual Model. The aim of this longitudinal revelatory study was to illuminate the process of redemption in a life, which leads to restoration and wholeness. This study breaks with traditional psychobiography – in that a life in progress has been selected; and personality development is not the key focus. This psychobiographical undertaking was anchored in qualitative research in the form of a single case study. Four types of triangulation were utilized, namely: data, investigators, theory and methodological triangulation. In addition, Alexander‟s identifiers of saliency, Miles and Huberman‟s data-management guidelines, Schultz‟s prototypical scenes, and Guba‟s criteria for trustworthiness, guided the methodology to ensure reliable data extraction and interpretation. The present researcher was in search of a deeper understanding of the enabling factors facilitating a restorative process in a life that was challenged by setbacks. Given the increasing pressures facing individuals in this modern era, the redemptive theme holds particular relevance, and was graphically demonstrated in the life of the participant who experienced trauma, widowhood, divorce, single parenthood, and a spate of medical and psychological setbacks. The findings suggest that the mental health clinician‟s utilisation of Frankl‟s conceptualisation of meaning in the most challenging circumstances, proffers itself as an all-purpose life-tool which enables individuals to overcome their challenges. The study demonstrated that gaining meaning in life is inextricably tied to an implicit legacy-oriented worldview. Of significance, is the role of forgiveness which emerged as the central redemptive catalyst. In this study, the resolution of past hurts through forgiveness, and the search for meaning, merge, forming an arterial theme in the life story of the participant. The dual impact of these factors not only reversed contaminated life-scripts, it also birthed a new calling in life which set the participant on a generative life course. The findings related to a redemptive life not only confirms existing theory, but also adds perspectives not previously considered. In addition, the findings related to the role of forgiveness has positive implications for the individual‟s physical and psychological wellbeing. Greater intentionality on the part of therapists to thread forgiveness into their practice, remains invitational in the light of the eugraphic impact demonstrated in this study.
- Full Text:
- Date Issued: 2013
Persistence and virulence of promising entomopathogenic fungal isolates for use in citrus orchards in South Africa
- Coombes, Candice A, Hill, Martin P, Moore, Sean D, Dames, Joanna F, Fullard, T
- Authors: Coombes, Candice A , Hill, Martin P , Moore, Sean D , Dames, Joanna F , Fullard, T
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416893 , vital:71394 , xlink:href="https://doi.org/10.1080/09583157.2013.819489"
- Description: Thaumatotibia leucotreta (Meyrick) (1912) (Lepidoptera: Tortricidae) is a key economic pest of citrus in South Africa. Although a variety of control options are available, none currently registered target the soil-dwelling life stages of the pest. Three fungal isolates, two Metarhizium anisopliae sensu lato Metschnikoff (Sorokin) isolates (G 11 3 L6 and FCM Ar 23 B3) and one Beauveria bassiana sensu lato Balsamo (Vuillemin) isolate (G Ar 17 B3) have been identified as showing the greatest potential against T. leucotreta soil-dwelling life stages. Since environmental persistence is an important factor in the success of entomopathogenic fungi against soil pests, the isolates, along with two commercial isolates (B. bassiana Eco-Bb® and M. anisopliae ICIPE 69), were subjected to a six-month field persistence trial. Every month after burial of the fungal isolates, inside net bags, in orchard soil, the number of colony forming units (CFUs) per gram of soil was measured and the viability of the conidia was assessed using bioassays. All isolates investigated were capable of persisting in the soil for the duration of the trial period and in addition, were capable of initiating infection in T. leucotreta late fifth instar larvae and subsequent pupae. However, with the exception of the commercial isolates which showed some correlation, no correlation was found between the number of CFUs recorded and percentage T. leucotreta mycosis. Persistence of entomopathogenic fungi in the field is affected by a series of factors, and although the effect of these factors was not measured, the data have provided preliminary evidence towards the persistence capability of these candidate biopesticides against T. leucotreta.
- Full Text:
- Date Issued: 2013
- Authors: Coombes, Candice A , Hill, Martin P , Moore, Sean D , Dames, Joanna F , Fullard, T
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416893 , vital:71394 , xlink:href="https://doi.org/10.1080/09583157.2013.819489"
- Description: Thaumatotibia leucotreta (Meyrick) (1912) (Lepidoptera: Tortricidae) is a key economic pest of citrus in South Africa. Although a variety of control options are available, none currently registered target the soil-dwelling life stages of the pest. Three fungal isolates, two Metarhizium anisopliae sensu lato Metschnikoff (Sorokin) isolates (G 11 3 L6 and FCM Ar 23 B3) and one Beauveria bassiana sensu lato Balsamo (Vuillemin) isolate (G Ar 17 B3) have been identified as showing the greatest potential against T. leucotreta soil-dwelling life stages. Since environmental persistence is an important factor in the success of entomopathogenic fungi against soil pests, the isolates, along with two commercial isolates (B. bassiana Eco-Bb® and M. anisopliae ICIPE 69), were subjected to a six-month field persistence trial. Every month after burial of the fungal isolates, inside net bags, in orchard soil, the number of colony forming units (CFUs) per gram of soil was measured and the viability of the conidia was assessed using bioassays. All isolates investigated were capable of persisting in the soil for the duration of the trial period and in addition, were capable of initiating infection in T. leucotreta late fifth instar larvae and subsequent pupae. However, with the exception of the commercial isolates which showed some correlation, no correlation was found between the number of CFUs recorded and percentage T. leucotreta mycosis. Persistence of entomopathogenic fungi in the field is affected by a series of factors, and although the effect of these factors was not measured, the data have provided preliminary evidence towards the persistence capability of these candidate biopesticides against T. leucotreta.
- Full Text:
- Date Issued: 2013
Entomopathogenic fungi for control of soil-borne life stages of false codling moth, Thaumatotibia leucotreta (Meyrick) (1912) (Lepidoptera: Tortricidae)
- Authors: Coombes, Candice Anne
- Date: 2013
- Subjects: Tortricidae , Lepidoptera , Cryptophlebia leucotreta , Insect pests -- Biological control -- South Africa -- Eastern Cape , Tortricidae -- Biological control -- South Africa -- Eastern Cape , Citrus -- Diseases and pests -- Biological control -- South Africa -- Eastern Cape , Entomopathogenic fungi , Fungi as biological pest control agents , Biological pest control agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5607 , http://hdl.handle.net/10962/d1002057 , Tortricidae , Lepidoptera , Cryptophlebia leucotreta , Insect pests -- Biological control -- South Africa -- Eastern Cape , Tortricidae -- Biological control -- South Africa -- Eastern Cape , Citrus -- Diseases and pests -- Biological control -- South Africa -- Eastern Cape , Entomopathogenic fungi , Fungi as biological pest control agents , Biological pest control agents
- Description: False codling moth (FCM), Thaumatotibia leucotreta is an extremely important pest of citrus in South Africa and with the shift away from the use of chemicals, alternate control options are needed. One avenue of control which has only recently been investigated against the soil-borne life stages of FCM is the use of entomopathogenic fungi (EPF). In 2009, 12 entomopathogenic fungal isolates collected from South African citrus orchards showed good control potential during laboratory conducted bioassays. The aim of this study was to further analyse the potential of these isolates through concentration-dose and exposure-time response bioassays. After initial re-screening, concentration-dose response and exposure-time response sandconidial bioassays, three isolates were identified as exhibiting the greatest control potential against FCM in soil, Metarhizium anisopliae var. anisopliae (G 11 3 L6 and FCM Ar 23 B3) and Beauveria bassiana (G Ar 17 B3). Percentage mycosis was found to be directly related to fungal concentration as well as the amount of time FCM 5th instar larvae were exposed to the fungal conidia. LC50 values for the three isolates were not greater than 1.92 x 10⁶ conidia.ml⁻ₑ and at the LC₅₀, FCM 5th instar larvae would need to be exposed to the fungus for a maximum of 13 days to ensure a high mortality level. These isolates along with two commercially available EPF products were subjected to field persistence trials whereby net bags filled with a mixture of autoclaved sand and formulated fungal product were buried in an Eastern Cape citrus orchard. The viability of each isolate was measured on a monthly basis for a period of six months. All isolates were capable of persisting in the soil for six months with the collected isolates persisting far better than the commercially used isolates. Two of the isolates, G 11 3 L6 and G Ar 17 B3, were subjected to small scale laboratory application trials. Two formulations were investigated at two concentrations. For each isolate, each formulation and each concentration, FCM 5th instar larvae were applied and allowed to burrow into the soil to pupate before fungal application or after fungal application. Contact between fungi and FCM host is essential as, in contrast to pre-larval treatments, percentage mortality in post-larval treatments was low for both formulations and both isolates. For isolate G Ar 17 B3, a conidial suspension applied as a spray at a concentration of 1 x 10⁷ conidia.ml⁻ₑ obtained the highest percentage mortality (80 %). For isolate G 11 3 L6 however, both formulations performed equally well at a high, 1 x10⁷ conidia.ml⁻ₑ concentration (conidial suspension: 60 %; granular: 65 %) The results obtained thus far are promising for the control of FCM in citrus, but if these EPFs are to successfully integrate into current FCM control practices more research, some of which is discussed, is essential
- Full Text:
- Date Issued: 2013
- Authors: Coombes, Candice Anne
- Date: 2013
- Subjects: Tortricidae , Lepidoptera , Cryptophlebia leucotreta , Insect pests -- Biological control -- South Africa -- Eastern Cape , Tortricidae -- Biological control -- South Africa -- Eastern Cape , Citrus -- Diseases and pests -- Biological control -- South Africa -- Eastern Cape , Entomopathogenic fungi , Fungi as biological pest control agents , Biological pest control agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5607 , http://hdl.handle.net/10962/d1002057 , Tortricidae , Lepidoptera , Cryptophlebia leucotreta , Insect pests -- Biological control -- South Africa -- Eastern Cape , Tortricidae -- Biological control -- South Africa -- Eastern Cape , Citrus -- Diseases and pests -- Biological control -- South Africa -- Eastern Cape , Entomopathogenic fungi , Fungi as biological pest control agents , Biological pest control agents
- Description: False codling moth (FCM), Thaumatotibia leucotreta is an extremely important pest of citrus in South Africa and with the shift away from the use of chemicals, alternate control options are needed. One avenue of control which has only recently been investigated against the soil-borne life stages of FCM is the use of entomopathogenic fungi (EPF). In 2009, 12 entomopathogenic fungal isolates collected from South African citrus orchards showed good control potential during laboratory conducted bioassays. The aim of this study was to further analyse the potential of these isolates through concentration-dose and exposure-time response bioassays. After initial re-screening, concentration-dose response and exposure-time response sandconidial bioassays, three isolates were identified as exhibiting the greatest control potential against FCM in soil, Metarhizium anisopliae var. anisopliae (G 11 3 L6 and FCM Ar 23 B3) and Beauveria bassiana (G Ar 17 B3). Percentage mycosis was found to be directly related to fungal concentration as well as the amount of time FCM 5th instar larvae were exposed to the fungal conidia. LC50 values for the three isolates were not greater than 1.92 x 10⁶ conidia.ml⁻ₑ and at the LC₅₀, FCM 5th instar larvae would need to be exposed to the fungus for a maximum of 13 days to ensure a high mortality level. These isolates along with two commercially available EPF products were subjected to field persistence trials whereby net bags filled with a mixture of autoclaved sand and formulated fungal product were buried in an Eastern Cape citrus orchard. The viability of each isolate was measured on a monthly basis for a period of six months. All isolates were capable of persisting in the soil for six months with the collected isolates persisting far better than the commercially used isolates. Two of the isolates, G 11 3 L6 and G Ar 17 B3, were subjected to small scale laboratory application trials. Two formulations were investigated at two concentrations. For each isolate, each formulation and each concentration, FCM 5th instar larvae were applied and allowed to burrow into the soil to pupate before fungal application or after fungal application. Contact between fungi and FCM host is essential as, in contrast to pre-larval treatments, percentage mortality in post-larval treatments was low for both formulations and both isolates. For isolate G Ar 17 B3, a conidial suspension applied as a spray at a concentration of 1 x 10⁷ conidia.ml⁻ₑ obtained the highest percentage mortality (80 %). For isolate G 11 3 L6 however, both formulations performed equally well at a high, 1 x10⁷ conidia.ml⁻ₑ concentration (conidial suspension: 60 %; granular: 65 %) The results obtained thus far are promising for the control of FCM in citrus, but if these EPFs are to successfully integrate into current FCM control practices more research, some of which is discussed, is essential
- Full Text:
- Date Issued: 2013
A Comparative study of two copper(II) based metal-organic frameworks : Cu2¼(OH)½B4C•8H2O and Cu2Na(OH)B4C•7H2O
- Authors: Coombes, Matthew
- Date: 2013
- Subjects: Copper , Organometallic compounds , Supramolecular organometallic chemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4533 , http://hdl.handle.net/10962/d1016245
- Description: This study focussed on two copper(II)-containing metal-organic frameworks (MOFs): Cu2Na(OH)B4C•7H2O and Cu2¼(OH)½B4C•8H2O (B4C = 1,2,4,5- benzenetetracarboxylate). They are both covalent, three-dimensional metalorganic framework polymers containing voids filled with water molecules. Both were characterised by elemental analysis, infrared spectroscopy, X-ray powder diffractometry (both in situ and regular), thermogravimetric analysis, differential scanning calorimetry and X-ray photoelectron spectroscopy. These two MOFs are essentially identical, with the only difference being the substitution of sodium by copper at every 4th site (disordered throughout the crystal). The guest inclusion properties of both MOFs were studied and compared. Although both structures collapse on dehydration, it was observed that Cu2Na(OH)B4C•7H2O is able to take up signifcant amounts of water, methanol and ethanol. All these processes are fully reversible. Car-Parrinello molecular dynamics studies suggest that it is a strong interaction between the oxygen atoms on these molecules with the sodium cation of the MOF that is responsible for this signifcant uptake. In contrast, Cu2¼ (OH)½ B4C•8H2O, the MOF without a sodium cation, did not demonstrate any methanol or ethanol uptake, but was able to take up some water. The uptake of water, however, is not a fully reversible process. The absence of sodium likely results in insuffcient energy to draw methanol and ethanol into the framework, while a subtle rotation of a carboxylate group on dehydration decreases the ability of the framework to form hydrogen bonds, thus reducing the ability to take up water. A series of hydrothermal syntheses were performed in order to develop a method of synthesis superior to the current gel-based synthesis that requires several months and has poor yields. The hydrothermal products were characterized by elemental analysis, infrared spectroscopy, X-ray powder diffractometry, thermogravimetric analysis and differential scanning calorimetry. It was shown that the MOF Cu2Na(OH)B4C•7H2O may be synthesised in almost 100% yield by using a temperature of 120°C over a period of 72 hours. It was not possible to synthesise Cu2¼ (OH)½ B4C•8H2O in a 100% yield - it was only obtained as a minor product.
- Full Text:
- Date Issued: 2013
- Authors: Coombes, Matthew
- Date: 2013
- Subjects: Copper , Organometallic compounds , Supramolecular organometallic chemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4533 , http://hdl.handle.net/10962/d1016245
- Description: This study focussed on two copper(II)-containing metal-organic frameworks (MOFs): Cu2Na(OH)B4C•7H2O and Cu2¼(OH)½B4C•8H2O (B4C = 1,2,4,5- benzenetetracarboxylate). They are both covalent, three-dimensional metalorganic framework polymers containing voids filled with water molecules. Both were characterised by elemental analysis, infrared spectroscopy, X-ray powder diffractometry (both in situ and regular), thermogravimetric analysis, differential scanning calorimetry and X-ray photoelectron spectroscopy. These two MOFs are essentially identical, with the only difference being the substitution of sodium by copper at every 4th site (disordered throughout the crystal). The guest inclusion properties of both MOFs were studied and compared. Although both structures collapse on dehydration, it was observed that Cu2Na(OH)B4C•7H2O is able to take up signifcant amounts of water, methanol and ethanol. All these processes are fully reversible. Car-Parrinello molecular dynamics studies suggest that it is a strong interaction between the oxygen atoms on these molecules with the sodium cation of the MOF that is responsible for this signifcant uptake. In contrast, Cu2¼ (OH)½ B4C•8H2O, the MOF without a sodium cation, did not demonstrate any methanol or ethanol uptake, but was able to take up some water. The uptake of water, however, is not a fully reversible process. The absence of sodium likely results in insuffcient energy to draw methanol and ethanol into the framework, while a subtle rotation of a carboxylate group on dehydration decreases the ability of the framework to form hydrogen bonds, thus reducing the ability to take up water. A series of hydrothermal syntheses were performed in order to develop a method of synthesis superior to the current gel-based synthesis that requires several months and has poor yields. The hydrothermal products were characterized by elemental analysis, infrared spectroscopy, X-ray powder diffractometry, thermogravimetric analysis and differential scanning calorimetry. It was shown that the MOF Cu2Na(OH)B4C•7H2O may be synthesised in almost 100% yield by using a temperature of 120°C over a period of 72 hours. It was not possible to synthesise Cu2¼ (OH)½ B4C•8H2O in a 100% yield - it was only obtained as a minor product.
- Full Text:
- Date Issued: 2013
Taxing recurrent services rendered by a foreign company to an associated enterprise in South Africa
- Costa, David Patrick Anthony
- Authors: Costa, David Patrick Anthony
- Date: 2013
- Subjects: Vienna Convention on the Law of Treaties (1969) Tax administration and procedure -- South Africa Double taxation -- South Africa Income tax -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:906 , http://hdl.handle.net/10962/d1008269
- Description: The objective of the study was to investigate the right of the South African Government to tax the income earned by a foreign company when rendering services in South Africa to a South African associated enterprise on a recurrent basis, together with the right to tax the amounts paid to the employees of the permanent establishment for services rendered in South Africa. At the same time the research investigated whether the services rendered by a foreign company to an associated enterprise in South Africa on a recurrent basis would constitute a permanent establishment, as this is essential before South Africa may tax either the foreign company or the employees of the permanent establishment (where such employees are not resident in South Africa).The research was conducted by means of a critical analysis of documentary data and data from a limited number of interviews with academics and the authors of textbooks and articles. In order to limit the scope of the research, a number of assumptions were made. Conflicting viewpoints underlying certain of these assumptions were discussed. Some of the important conclusions reached are that the provisions of the Vienna Convention on the Law of Treaties should be taken into account when interpreting South African legislation (including Double Tax Agreements), and that the Organisation for Economic Cooperation and Development (OECD) Commentary may be relied upon when interpreting OECD based Double Tax Agreements in South Africa. No conclusion was reached on whether to apply an ambulatory or a static basis of interpreting the OECD Commentary, however. The final conclusion of the research is that the services rendered in South Africa on a recurrent basis would be geographically and commercially coherent and consequently meet the "location test'. It is clear that as the services are rendered regularly and recurrently, they would be regarded as having the necessary permanence and would meet the 'duration test'. The place of business would therefore be regarded as being fixed (having the necessary degree of permanence). As the services would be rendered at the place of business of the South African entity, they would be regarded as being rendered 'through' the place of business and the foreign entity would be regarded as having a permanent establishment in South Africa (as defined in Article 5(1) of the OECD Model Tax Convention}. The South African Government would therefore be entitled to tax the income attributable to the permanent establishment and the income earned by the non resident employees, who rendered services in South Africa for the permanent establishment. Once the entitlement to tax exists, South African legislative rules determine how South Africa proceeds to tax the income.
- Full Text:
- Date Issued: 2013
- Authors: Costa, David Patrick Anthony
- Date: 2013
- Subjects: Vienna Convention on the Law of Treaties (1969) Tax administration and procedure -- South Africa Double taxation -- South Africa Income tax -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:906 , http://hdl.handle.net/10962/d1008269
- Description: The objective of the study was to investigate the right of the South African Government to tax the income earned by a foreign company when rendering services in South Africa to a South African associated enterprise on a recurrent basis, together with the right to tax the amounts paid to the employees of the permanent establishment for services rendered in South Africa. At the same time the research investigated whether the services rendered by a foreign company to an associated enterprise in South Africa on a recurrent basis would constitute a permanent establishment, as this is essential before South Africa may tax either the foreign company or the employees of the permanent establishment (where such employees are not resident in South Africa).The research was conducted by means of a critical analysis of documentary data and data from a limited number of interviews with academics and the authors of textbooks and articles. In order to limit the scope of the research, a number of assumptions were made. Conflicting viewpoints underlying certain of these assumptions were discussed. Some of the important conclusions reached are that the provisions of the Vienna Convention on the Law of Treaties should be taken into account when interpreting South African legislation (including Double Tax Agreements), and that the Organisation for Economic Cooperation and Development (OECD) Commentary may be relied upon when interpreting OECD based Double Tax Agreements in South Africa. No conclusion was reached on whether to apply an ambulatory or a static basis of interpreting the OECD Commentary, however. The final conclusion of the research is that the services rendered in South Africa on a recurrent basis would be geographically and commercially coherent and consequently meet the "location test'. It is clear that as the services are rendered regularly and recurrently, they would be regarded as having the necessary permanence and would meet the 'duration test'. The place of business would therefore be regarded as being fixed (having the necessary degree of permanence). As the services would be rendered at the place of business of the South African entity, they would be regarded as being rendered 'through' the place of business and the foreign entity would be regarded as having a permanent establishment in South Africa (as defined in Article 5(1) of the OECD Model Tax Convention}. The South African Government would therefore be entitled to tax the income attributable to the permanent establishment and the income earned by the non resident employees, who rendered services in South Africa for the permanent establishment. Once the entitlement to tax exists, South African legislative rules determine how South Africa proceeds to tax the income.
- Full Text:
- Date Issued: 2013
An exploratory study of techniques in passive network telescope data analysis
- Authors: Cowie, Bradley
- Date: 2013
- Subjects: Web search engines Internet searching World Wide Web Malware (Computer software) Computer viruses Computer networks -- Monitoring Computer networks -- Security measures
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4573 , http://hdl.handle.net/10962/d1002038
- Description: Careful examination of the composition and concentration of malicious traffic in transit on the channels of the Internet provides network administrators with a means of understanding and predicting damaging attacks directed towards their networks. This allows for action to be taken to mitigate the effect that these attacks have on the performance of their networks and the Internet as a whole by readying network defences and providing early warning to Internet users. One approach to malicious traffic monitoring that has garnered some success in recent times, as exhibited by the study of fast spreading Internet worms, involves analysing data obtained from network telescopes. While some research has considered using measures derived from network telescope datasets to study large scale network incidents such as Code-Red, SQLSlammer and Conficker, there is very little documented discussion on the merits and weaknesses of approaches to analyzing network telescope data. This thesis is an introductory study in network telescope analysis and aims to consider the variables associated with the data received by network telescopes and how these variables may be analysed. The core research of this thesis considers both novel and previously explored analysis techniques from the fields of security metrics, baseline analysis, statistical analysis and technical analysis as applied to analysing network telescope datasets. These techniques were evaluated as approaches to recognize unusual behaviour by observing the ability of these techniques to identify notable incidents in network telescope datasets
- Full Text:
- Date Issued: 2013
- Authors: Cowie, Bradley
- Date: 2013
- Subjects: Web search engines Internet searching World Wide Web Malware (Computer software) Computer viruses Computer networks -- Monitoring Computer networks -- Security measures
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4573 , http://hdl.handle.net/10962/d1002038
- Description: Careful examination of the composition and concentration of malicious traffic in transit on the channels of the Internet provides network administrators with a means of understanding and predicting damaging attacks directed towards their networks. This allows for action to be taken to mitigate the effect that these attacks have on the performance of their networks and the Internet as a whole by readying network defences and providing early warning to Internet users. One approach to malicious traffic monitoring that has garnered some success in recent times, as exhibited by the study of fast spreading Internet worms, involves analysing data obtained from network telescopes. While some research has considered using measures derived from network telescope datasets to study large scale network incidents such as Code-Red, SQLSlammer and Conficker, there is very little documented discussion on the merits and weaknesses of approaches to analyzing network telescope data. This thesis is an introductory study in network telescope analysis and aims to consider the variables associated with the data received by network telescopes and how these variables may be analysed. The core research of this thesis considers both novel and previously explored analysis techniques from the fields of security metrics, baseline analysis, statistical analysis and technical analysis as applied to analysing network telescope datasets. These techniques were evaluated as approaches to recognize unusual behaviour by observing the ability of these techniques to identify notable incidents in network telescope datasets
- Full Text:
- Date Issued: 2013
What future graduates will value in their leaders: a study across gender and culture
- Authors: Cox, Andrea
- Date: 2013
- Subjects: Leadership -- South Africa Leadership -- Evaluation -- South Africa Culture -- South Africa Social values -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1195 , http://hdl.handle.net/10962/d1008197
- Description: Effective leadership has been found to be a key determinant of organisational success. Effective leadership does not only involve the ability to influence and inspire others, it is the ability to lead subordinates according to the competencies that they value. The focus of this study is on determining what in fact the future South African graduate workforce will value in a leader. Effective leadership and the competencies that subordinate's value is especially relevant today as leadership is forced to contend with an increasingly diverse workforce. This diversity necessitates the need for a leadership style to be congruent with what subordinates of diverse genders and cultures will value, so to be effective. Existing studies have indicated that gender and culture influence what subordinate's value in a leader, however it is evident from the results of this study, that this is not entirely the case. Regarding gender, the female and male respondents in this study value similar competencies in their leader, indicating that there is no distinct set of competencies that will be valued by male and female graduates. With respect to culture, the respondents value a mixture of competencies that combine both African and Western leadership practices, values and philosophies, indicating that there is no distinct set of competencies that will be valued by African, Coloured, Indian and White graduates. On the basis of this research, the recommendation is that for leaders to be effective in the 21 st century, a leader must be loyal and inspirational, have vision and integrity and lastly must be open and honest with their subordinates
- Full Text:
- Date Issued: 2013
- Authors: Cox, Andrea
- Date: 2013
- Subjects: Leadership -- South Africa Leadership -- Evaluation -- South Africa Culture -- South Africa Social values -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1195 , http://hdl.handle.net/10962/d1008197
- Description: Effective leadership has been found to be a key determinant of organisational success. Effective leadership does not only involve the ability to influence and inspire others, it is the ability to lead subordinates according to the competencies that they value. The focus of this study is on determining what in fact the future South African graduate workforce will value in a leader. Effective leadership and the competencies that subordinate's value is especially relevant today as leadership is forced to contend with an increasingly diverse workforce. This diversity necessitates the need for a leadership style to be congruent with what subordinates of diverse genders and cultures will value, so to be effective. Existing studies have indicated that gender and culture influence what subordinate's value in a leader, however it is evident from the results of this study, that this is not entirely the case. Regarding gender, the female and male respondents in this study value similar competencies in their leader, indicating that there is no distinct set of competencies that will be valued by male and female graduates. With respect to culture, the respondents value a mixture of competencies that combine both African and Western leadership practices, values and philosophies, indicating that there is no distinct set of competencies that will be valued by African, Coloured, Indian and White graduates. On the basis of this research, the recommendation is that for leaders to be effective in the 21 st century, a leader must be loyal and inspirational, have vision and integrity and lastly must be open and honest with their subordinates
- Full Text:
- Date Issued: 2013
The effect of using a computer-based exploration tool on children's career development learning
- Authors: Crause, Ewald
- Date: 2013
- Subjects: Vocational guidance -- Computer network resources , Career development -- Computer network resources
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9947 , http://hdl.handle.net/10948/d1015020
- Description: Historically the process of career development was thought of as occurring in adolescence and adulthood; however, the renewed emphasis on lifelong career development has led to a greater focus on the career developmental stage of childhood. The present research focused on the development and trialling of a research-based computerised career exploration tool, Growing-up: Children Building Careers™ (GCBC™) that can be used for early intervention in children‘s career development. The integration of developmental considerations within a career developmental context is of paramount importance, considering that child and career developmental theories share certain basic foundational principles such as the dual recognition of identifiable life stages and the resolution or accomplishment of associated tasks. The focus of the research is to provide access to a research-based tool that can assist learners with developing age appropriate career developmental skills. As the overview of education policy and existing programs will show, there are challenges in providing access to and improving the nature, level, and quality of career development services. Gaps in access to career development learning are particularly evident at the elementary education level. Furthermore it is clear that learners need to be at the centre of a radical rethink of careers services within a lifelong learning framework in order to ensure access to navigational tools throughout a lifetime of work and study transitions. Digital environments, such as the GCBC™, are tools that broaden and extend learning possibilities for children and appropriately designed digital environments can provide a vehicle that can take children further than they might travel unassisted. The research is divided into five phases and includes eight to ten year old children as participants. Phase one focused on the program design and pilot study (ensuring content validity and age-appropriate language use), while phases two to five focused on the fieldwork (i.e., pre –test, program exposure, post-test, and focus group discussions). The researcher made use of a mixed research design that combines both quantitative and qualitative research methods. The total sample consisted of 146 children between the ages of eight to ten years old. The control group had 72 children and the experimental group 74 children with a mean age of 8.74 years (SD = 0.63) for the total sample. The quantitative data collection entailed a pre-and post-test design with learners‘ career development measured with the Childhood Career Development Scale (CCDS) and their career awareness with the Revised Career Awareness Survey (RCAS). Qualitative data was collected in the form of two focus group discussions, which included a small sample of children from the experimental group, as well as insights gained from educators following the GCBC™ fieldwork. The quantitative statistical analysis included descriptive and inferential statistics which allowed the researcher to not only describe the research findings, but to confirm the effectiveness of the GCBC™ as an intentional career development learning program. Furthermore, the responses of the children and educators who participated in or witnessed the facilitation of the GCBC™ provided support for the GCBC™ as a meaningful career learning experience which can be successfully implemented in educational settings.
- Full Text:
- Date Issued: 2013
- Authors: Crause, Ewald
- Date: 2013
- Subjects: Vocational guidance -- Computer network resources , Career development -- Computer network resources
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9947 , http://hdl.handle.net/10948/d1015020
- Description: Historically the process of career development was thought of as occurring in adolescence and adulthood; however, the renewed emphasis on lifelong career development has led to a greater focus on the career developmental stage of childhood. The present research focused on the development and trialling of a research-based computerised career exploration tool, Growing-up: Children Building Careers™ (GCBC™) that can be used for early intervention in children‘s career development. The integration of developmental considerations within a career developmental context is of paramount importance, considering that child and career developmental theories share certain basic foundational principles such as the dual recognition of identifiable life stages and the resolution or accomplishment of associated tasks. The focus of the research is to provide access to a research-based tool that can assist learners with developing age appropriate career developmental skills. As the overview of education policy and existing programs will show, there are challenges in providing access to and improving the nature, level, and quality of career development services. Gaps in access to career development learning are particularly evident at the elementary education level. Furthermore it is clear that learners need to be at the centre of a radical rethink of careers services within a lifelong learning framework in order to ensure access to navigational tools throughout a lifetime of work and study transitions. Digital environments, such as the GCBC™, are tools that broaden and extend learning possibilities for children and appropriately designed digital environments can provide a vehicle that can take children further than they might travel unassisted. The research is divided into five phases and includes eight to ten year old children as participants. Phase one focused on the program design and pilot study (ensuring content validity and age-appropriate language use), while phases two to five focused on the fieldwork (i.e., pre –test, program exposure, post-test, and focus group discussions). The researcher made use of a mixed research design that combines both quantitative and qualitative research methods. The total sample consisted of 146 children between the ages of eight to ten years old. The control group had 72 children and the experimental group 74 children with a mean age of 8.74 years (SD = 0.63) for the total sample. The quantitative data collection entailed a pre-and post-test design with learners‘ career development measured with the Childhood Career Development Scale (CCDS) and their career awareness with the Revised Career Awareness Survey (RCAS). Qualitative data was collected in the form of two focus group discussions, which included a small sample of children from the experimental group, as well as insights gained from educators following the GCBC™ fieldwork. The quantitative statistical analysis included descriptive and inferential statistics which allowed the researcher to not only describe the research findings, but to confirm the effectiveness of the GCBC™ as an intentional career development learning program. Furthermore, the responses of the children and educators who participated in or witnessed the facilitation of the GCBC™ provided support for the GCBC™ as a meaningful career learning experience which can be successfully implemented in educational settings.
- Full Text:
- Date Issued: 2013
Wireless mobile android technology in the monitoring and control of a safety integrated robotic cell
- Authors: Cumberlege, Aidan
- Date: 2013
- Subjects: Android (Electronic resource) , Application software -- Development , Computer software -- Development , Mobile computing
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/46284 , vital:39543
- Description: The constant strive for improving the efficiency of production processes has become a worldwide challenge. In high speed production facilities response time between man and machine is of utmost importance when financial implications are taken into account. This dissertation contributes to improving the response time by making use of wireless notification between the machine and the maintenance technician when process faults occur. The tool used to achieve this is based on Android. Research is carried out on the latest Android technology while taking the safety aspects of a production environment into consideration. Research in designing a rule based intelligent system is established by using a tablet as the user interface for automatic notification and corrective action recommendations. Quick response is achieved by setting up a wireless network. As a result of designing a wireless intelligent maintenance tool, production downtime is improved. Management can recall all activities logged by the system for graphical representation.
- Full Text:
- Date Issued: 2013
Wireless mobile android technology in the monitoring and control of a safety integrated robotic cell
- Authors: Cumberlege, Aidan
- Date: 2013
- Subjects: Android (Electronic resource) , Application software -- Development , Computer software -- Development , Mobile computing
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/46284 , vital:39543
- Description: The constant strive for improving the efficiency of production processes has become a worldwide challenge. In high speed production facilities response time between man and machine is of utmost importance when financial implications are taken into account. This dissertation contributes to improving the response time by making use of wireless notification between the machine and the maintenance technician when process faults occur. The tool used to achieve this is based on Android. Research is carried out on the latest Android technology while taking the safety aspects of a production environment into consideration. Research in designing a rule based intelligent system is established by using a tablet as the user interface for automatic notification and corrective action recommendations. Quick response is achieved by setting up a wireless network. As a result of designing a wireless intelligent maintenance tool, production downtime is improved. Management can recall all activities logged by the system for graphical representation.
- Full Text:
- Date Issued: 2013
Land claims and the pursuit of co-management on four protected areas in South Africa
- Cundill, Georgina, Thondhlana, Gladman, Sisitka, Lawrence, Shackleton, Sheona, Blorea, M
- Authors: Cundill, Georgina , Thondhlana, Gladman , Sisitka, Lawrence , Shackleton, Sheona , Blorea, M
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391223 , vital:68632 , xlink:href="https://doi.org/10.1016/j.landusepol.2013.05.016"
- Description: Successful land claims on protected areas by previously disenfranchised communities often result in co-management agreements between claimant communities and state conservation agencies. South Africa, in particular, has pursued co-management as the desired outcome of land claims on its protected areas. We review four cases of co-management on protected areas in South Africa, and reflect on the appropriateness of the pursuit of co-management as the preferred outcome of land claims. Despite promises of pro-poor, democratically informed management, the practical experience of co-management has seen the continuation of the status quo in terms of conservation, with very few material benefits for claimant communities and limited sharing of responsibilities and decision-making functions. The findings underscore two deep challenges facing co-management in cases of land claims worldwide. First, during land claims negotiations in cases involving protected areas, the state cannot be expected to represent the best interests of its citizens (the land claimants), while simultaneously seeking to meet national and international obligations for protected area coverage. Second, the concept of democratic co-management may sit uncomfortably beside the realities of managing loss-making protected areas with ever-shrinking conservation budgets. Where co-management agreements have already been signed, ensuring that new landowners do indeed have a say in management should form the driving focus for co-management practice going forward.
- Full Text:
- Date Issued: 2013
- Authors: Cundill, Georgina , Thondhlana, Gladman , Sisitka, Lawrence , Shackleton, Sheona , Blorea, M
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391223 , vital:68632 , xlink:href="https://doi.org/10.1016/j.landusepol.2013.05.016"
- Description: Successful land claims on protected areas by previously disenfranchised communities often result in co-management agreements between claimant communities and state conservation agencies. South Africa, in particular, has pursued co-management as the desired outcome of land claims on its protected areas. We review four cases of co-management on protected areas in South Africa, and reflect on the appropriateness of the pursuit of co-management as the preferred outcome of land claims. Despite promises of pro-poor, democratically informed management, the practical experience of co-management has seen the continuation of the status quo in terms of conservation, with very few material benefits for claimant communities and limited sharing of responsibilities and decision-making functions. The findings underscore two deep challenges facing co-management in cases of land claims worldwide. First, during land claims negotiations in cases involving protected areas, the state cannot be expected to represent the best interests of its citizens (the land claimants), while simultaneously seeking to meet national and international obligations for protected area coverage. Second, the concept of democratic co-management may sit uncomfortably beside the realities of managing loss-making protected areas with ever-shrinking conservation budgets. Where co-management agreements have already been signed, ensuring that new landowners do indeed have a say in management should form the driving focus for co-management practice going forward.
- Full Text:
- Date Issued: 2013
A marine chemical ecology study of the sea hare, Bursatella leachii in South Africa
- Authors: D'Souza, Nicole
- Date: 2013 , 2013-03-22
- Subjects: Sea hares (Mollusks) -- South Africa -- Kenton-on-Sea , Sea hares (Mollusks) -- Ecology -- South Africa -- Kenton-on-Sea , Sea hares (Mollusks) -- Behavior -- South Africa -- Kenton-on-Sea , Sea hares (Mollusks) -- Defenses -- Behavior -- South Africa -- Kenton-on-Sea
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4283 , http://hdl.handle.net/10962/d1002952 , Sea hares (Mollusks) -- South Africa -- Kenton-on-Sea , Sea hares (Mollusks) -- Ecology -- South Africa -- Kenton-on-Sea , Sea hares (Mollusks) -- Behavior -- South Africa -- Kenton-on-Sea , Sea hares (Mollusks) -- Defenses -- Behavior -- South Africa -- Kenton-on-Sea
- Description: The large cosmopolitan sea hare Bursatella leachii is a common resident in Eastern Cape river mouths during summer and late autumn where they congregate in beds of Zostera capensis to breed. In this thesis, the previously known toxic formamide marine secondary metabolite (-)-bursatellin (2.2), which may deter predators of South African specimens of the globally distributed sea hare Bursatella leachii, was isolated and identified (Chapter 2). There have been no previous chemical ecology studies of B. leachii and the latter half of this thesis is devoted to chemical ecology studies of this organism. Interestingly, the isolation of the (-)-diastereomer of 2.2 from specimens of B. leachii collected from the Kariega River mouth (near Kenton-on-Sea) suggests that the South African specimens of this species are similar to specimens collected from Puerto Rico and from the Mediterranean Sea. Two different chromatographic techniques for isolating 2.2 were compared in order to maximize the amount of 2.2 isolated from the Kariega River mouth sea hares. The doubling of selected resonances observed in both the ¹H and ¹³C NMR spectra of the bursatellin isolated in this study suggest one of three possibilities; either firstly, the presence of closely related compound(s), secondly, the presence of diastereomers or thirdly the presence of rotamers. Through NMR kinetic studies, we were able to establish that the presence of rotamers was very unlikely due to no change in the relative ratio (3:1) of the ¹H NMR signals with an increase in temperature. Although the attempted synthesis of the acetate derivative (2.28), as a means of separating a diastereomeric mixture was successful, the chromatographic separation of the proposed acetylated diastereomers was not successful. Preparation of the camphanate ester derivatives (e.g. 2.30) proved to be unsuccessful. Five B. leachii specimens were dissected, their organs separated and individually extracted with methanol. The methanol extracts were individually chromatographed on HP-20 media, and the distribution of bursatellin determined by isolation and NMR. It was evident from this investigation that the distribution of 2.2 within individual B. leachii specimens was found to be highest within the B. leachii ink gland. The lower amounts of 2.2 contained in the digestive system, relative to other organs, was hypothesized to occur because 2.2 is sequestered from the diet of the sea hare and efficiently moved from the gut to various organs around the body where it is stored. The absence of 2.2 from the skin was surprising and may be a result of a smaller mass of skin relative to other organs coupled with the limitations of the chromatographic separation techniques employed. Surprisingly, no bursatellin was found within juvenile sea hares. Chapter three discusses the isolation of ilimaquinone (3.1) and pelorol (3.19) from the sponge Hippospongia metachroma and the structure elucidation of each compound using computer modeling to illustrate the conformation. It was deemed necessary to isolate these well known and abundant bioactive marine natural products from a sponge as standard compounds in the bioassays given the paucity of 2.2 available for this study. Chapter four describes the assays used to test the biological activity of the bursatellin 2.2 compared to the generally bioactive ilimaquinone and the structurally related and commercially available broad spectrum antibiotic chloramphenicol. B. leachii, a shell-less marine mollusc inhabits a variety of intertidal habitats and, therefore, is exposed to several different predators, yet does not appear to have any specific predators. Potential predators of this sea hare in the Kariega Estuary could be fish and amphipods which are found in close proximity to these sea hares. Results of the assays showed that at roughly natural concentrations, (calculated from the isolated chromatographic yield) feeding was deterred by the fish and amphipods, which implied that 2.2 may confer a defensive role within the organism. The relatively high concentration present within the ink gland of B. leachii may support this hypothesis. Surprisingly, given its structural similarity to chloramphenicol, 2.3 did not show any antimicrobial action against five of the six bacterial strains against which it was screened [chloramphenicol inhibited the growth of all the bacterial strains at very low concentrations (0.25 mg/mL)]. Bursatellin was found to be only active against Staphylococus aureus at high concentrations ca. 2 mg/mL when compared to chloramphenicol. Neither bursatellin nor chloramphenicol showed anti-fungal activity. Although this study suggests that the sea hares may use chemical defences in addition to opaline ink to defend themselves, they also live within the seagrass Z. capensis, which possibly provides the sea hare with a cryptic form of physical defence against several predators that are unable to swim freely within the weed beds in the littoral zone of the estuary. , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
- Authors: D'Souza, Nicole
- Date: 2013 , 2013-03-22
- Subjects: Sea hares (Mollusks) -- South Africa -- Kenton-on-Sea , Sea hares (Mollusks) -- Ecology -- South Africa -- Kenton-on-Sea , Sea hares (Mollusks) -- Behavior -- South Africa -- Kenton-on-Sea , Sea hares (Mollusks) -- Defenses -- Behavior -- South Africa -- Kenton-on-Sea
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4283 , http://hdl.handle.net/10962/d1002952 , Sea hares (Mollusks) -- South Africa -- Kenton-on-Sea , Sea hares (Mollusks) -- Ecology -- South Africa -- Kenton-on-Sea , Sea hares (Mollusks) -- Behavior -- South Africa -- Kenton-on-Sea , Sea hares (Mollusks) -- Defenses -- Behavior -- South Africa -- Kenton-on-Sea
- Description: The large cosmopolitan sea hare Bursatella leachii is a common resident in Eastern Cape river mouths during summer and late autumn where they congregate in beds of Zostera capensis to breed. In this thesis, the previously known toxic formamide marine secondary metabolite (-)-bursatellin (2.2), which may deter predators of South African specimens of the globally distributed sea hare Bursatella leachii, was isolated and identified (Chapter 2). There have been no previous chemical ecology studies of B. leachii and the latter half of this thesis is devoted to chemical ecology studies of this organism. Interestingly, the isolation of the (-)-diastereomer of 2.2 from specimens of B. leachii collected from the Kariega River mouth (near Kenton-on-Sea) suggests that the South African specimens of this species are similar to specimens collected from Puerto Rico and from the Mediterranean Sea. Two different chromatographic techniques for isolating 2.2 were compared in order to maximize the amount of 2.2 isolated from the Kariega River mouth sea hares. The doubling of selected resonances observed in both the ¹H and ¹³C NMR spectra of the bursatellin isolated in this study suggest one of three possibilities; either firstly, the presence of closely related compound(s), secondly, the presence of diastereomers or thirdly the presence of rotamers. Through NMR kinetic studies, we were able to establish that the presence of rotamers was very unlikely due to no change in the relative ratio (3:1) of the ¹H NMR signals with an increase in temperature. Although the attempted synthesis of the acetate derivative (2.28), as a means of separating a diastereomeric mixture was successful, the chromatographic separation of the proposed acetylated diastereomers was not successful. Preparation of the camphanate ester derivatives (e.g. 2.30) proved to be unsuccessful. Five B. leachii specimens were dissected, their organs separated and individually extracted with methanol. The methanol extracts were individually chromatographed on HP-20 media, and the distribution of bursatellin determined by isolation and NMR. It was evident from this investigation that the distribution of 2.2 within individual B. leachii specimens was found to be highest within the B. leachii ink gland. The lower amounts of 2.2 contained in the digestive system, relative to other organs, was hypothesized to occur because 2.2 is sequestered from the diet of the sea hare and efficiently moved from the gut to various organs around the body where it is stored. The absence of 2.2 from the skin was surprising and may be a result of a smaller mass of skin relative to other organs coupled with the limitations of the chromatographic separation techniques employed. Surprisingly, no bursatellin was found within juvenile sea hares. Chapter three discusses the isolation of ilimaquinone (3.1) and pelorol (3.19) from the sponge Hippospongia metachroma and the structure elucidation of each compound using computer modeling to illustrate the conformation. It was deemed necessary to isolate these well known and abundant bioactive marine natural products from a sponge as standard compounds in the bioassays given the paucity of 2.2 available for this study. Chapter four describes the assays used to test the biological activity of the bursatellin 2.2 compared to the generally bioactive ilimaquinone and the structurally related and commercially available broad spectrum antibiotic chloramphenicol. B. leachii, a shell-less marine mollusc inhabits a variety of intertidal habitats and, therefore, is exposed to several different predators, yet does not appear to have any specific predators. Potential predators of this sea hare in the Kariega Estuary could be fish and amphipods which are found in close proximity to these sea hares. Results of the assays showed that at roughly natural concentrations, (calculated from the isolated chromatographic yield) feeding was deterred by the fish and amphipods, which implied that 2.2 may confer a defensive role within the organism. The relatively high concentration present within the ink gland of B. leachii may support this hypothesis. Surprisingly, given its structural similarity to chloramphenicol, 2.3 did not show any antimicrobial action against five of the six bacterial strains against which it was screened [chloramphenicol inhibited the growth of all the bacterial strains at very low concentrations (0.25 mg/mL)]. Bursatellin was found to be only active against Staphylococus aureus at high concentrations ca. 2 mg/mL when compared to chloramphenicol. Neither bursatellin nor chloramphenicol showed anti-fungal activity. Although this study suggests that the sea hares may use chemical defences in addition to opaline ink to defend themselves, they also live within the seagrass Z. capensis, which possibly provides the sea hare with a cryptic form of physical defence against several predators that are unable to swim freely within the weed beds in the littoral zone of the estuary. , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
Effects of gold nanoparticle shape on the aggregation and fluorescence behaviour of water soluble zinc phthalocyanines
- D'Souza, Sarah, Moeno, Sharon, Antunes, Edith M, Nyokong, Tebello
- Authors: D'Souza, Sarah , Moeno, Sharon , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232500 , vital:49997 , xlink:href="https://doi.org/10.1039/C3NJ00146F"
- Description: The absorption and fluorescence response as well as the fluorescence quantum yields and lifetimes of sulfonated phthalocyanines and alkyl carboxylic acid substituted zinc phthalocyanines in the presence of differently shaped water soluble gold nanoparticles were studied. The respective phthalocyanines are known to be highly aggregated in water, which is reported to markedly reduce the excited state lifetimes. This paper shows that in the presence of star shaped gold nanoparticles, the degree of phthalocyanine aggregation in water is greatly reduced, but the aggregation status of the phthalocyanines does not change for spherical Au nanoparticles. Since gold nanoparticles have already proven to be useful in numerous nanomedicinal and nanomedical applications, the disaggregation of phthalocyanines is an added advantage.
- Full Text:
- Date Issued: 2013
- Authors: D'Souza, Sarah , Moeno, Sharon , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232500 , vital:49997 , xlink:href="https://doi.org/10.1039/C3NJ00146F"
- Description: The absorption and fluorescence response as well as the fluorescence quantum yields and lifetimes of sulfonated phthalocyanines and alkyl carboxylic acid substituted zinc phthalocyanines in the presence of differently shaped water soluble gold nanoparticles were studied. The respective phthalocyanines are known to be highly aggregated in water, which is reported to markedly reduce the excited state lifetimes. This paper shows that in the presence of star shaped gold nanoparticles, the degree of phthalocyanine aggregation in water is greatly reduced, but the aggregation status of the phthalocyanines does not change for spherical Au nanoparticles. Since gold nanoparticles have already proven to be useful in numerous nanomedicinal and nanomedical applications, the disaggregation of phthalocyanines is an added advantage.
- Full Text:
- Date Issued: 2013
An analysis of teacher's skills in the identification of learners with behavioural and emotional problems
- Authors: Damons, Thirza
- Date: 2013
- Subjects: Teachers -- Training of , Interaction analysis in education , Observation (Educational method)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:9451 , http://hdl.handle.net/10948/d1012183 , Teachers -- Training of , Interaction analysis in education , Observation (Educational method)
- Description: This study aimed to explore teachers‟ abilities to identify learners with behavioural and emotional problems, to examine the strategies that they implement to address the challenges and their measure of success in addressing these. This study was qualitative in nature and semi-structured interviews were conducted with 10 volunteer teachers located in the northern areas of Port Elizabeth and an additional 50 teachers completed open ended questionnaires. The learning areas taught by the teachers varied. Descriptive and content analysis procedures were utilized to analyze the findings. The findings indicated that teachers lack the skills and knowledge to assist learners with behavioural and emotional problems. The teachers tended to view their roles as imparting knowledge rather than tending to the mental health of learners so they did not adopt approaches to assist the learners with their behavioural and emotional challenges. This was in spite of the fact that the learners' psychological and physical well-being impacted their academic achievement.
- Full Text:
- Date Issued: 2013
- Authors: Damons, Thirza
- Date: 2013
- Subjects: Teachers -- Training of , Interaction analysis in education , Observation (Educational method)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:9451 , http://hdl.handle.net/10948/d1012183 , Teachers -- Training of , Interaction analysis in education , Observation (Educational method)
- Description: This study aimed to explore teachers‟ abilities to identify learners with behavioural and emotional problems, to examine the strategies that they implement to address the challenges and their measure of success in addressing these. This study was qualitative in nature and semi-structured interviews were conducted with 10 volunteer teachers located in the northern areas of Port Elizabeth and an additional 50 teachers completed open ended questionnaires. The learning areas taught by the teachers varied. Descriptive and content analysis procedures were utilized to analyze the findings. The findings indicated that teachers lack the skills and knowledge to assist learners with behavioural and emotional problems. The teachers tended to view their roles as imparting knowledge rather than tending to the mental health of learners so they did not adopt approaches to assist the learners with their behavioural and emotional challenges. This was in spite of the fact that the learners' psychological and physical well-being impacted their academic achievement.
- Full Text:
- Date Issued: 2013
Factors contributing to senior secondary school learners' poor performance in science subjects in the Mount Frere Education District of the Eastern Cape Province, South Africa
- Authors: Dandala, Siyolo Sebastian
- Date: 2013
- Subjects: Poor performance -- Science
- Language: English
- Type: Thesis , Masters , M Ed
- Identifier: vital:18462 , http://hdl.handle.net/11260/d1008256
- Description: The purpose of this study was to investigate the factors contributing to senior secondary school learners’ poor performance in science subjects in the Mount Frere Education District of the Eastern Cape Province, South Africa. The literature analyses critically the existing knowledge based on factors contributing to poor performance of learners in science subjects and those factors that impact on learners’ positive attitudes towards science subjects. The study also identified literature on the following: motivational levels of science learners, teaching and learning strategies used in teaching science subjects, medium of instruction in the teaching and learning of science subjects, parental involvement in children’s learning, effects of lack of instructional materials on learner performance and learners’ attitudes towards science subjects. The study also examined the views of learners, teachers, Head of Department of sciences, parents and principals on factors contributing to poor performance of senior secondary school learners inscience subjects. The population for the study comprised of all principals, science teachers, science Head of Department, parents and science learners of the twenty six (26) senior secondary schools in the Mount Frere Education District. The principals, science teachers, science Head of Departments, parents of science learners and science learners in seven (7) senior secondary schools that offered science subjects were used as a sample in this study. The study employed the mixed method of quantitative and qualitative approaches. The research designs used were the survey and the case study. The instruments used were the questionnaires in which closed-ended questions were used to secure information and the interviews where open ended questions were used to collect data. The questionnaire as an instrument got tested in the pilot study to investigate the validity and reliability and also to identify possible deficiencies so as to rectify them. The responses were analyzed and presented in percentages using the Statistical Package for Social Science (SPSS) in the quantitative approach method of data analysis and in the qualitative data analysis process the researcher read through the data and became familiar with it and then identified the main themes and the next step was to examine the data in-depth and to provide detail descriptions of the participants’ words. The researcher also categorised and coded the data and then grouped them into themes and finally, interpreted the organised data into conclusion. The findings revealed that there was a lack of parental involvement, shortage of instructional materials, shortage of school laboratories, shortage of qualified science teachers and the learners’ negative attitudes towards science subjects. Recommendations were made concerning the above findings.
- Full Text:
- Date Issued: 2013
- Authors: Dandala, Siyolo Sebastian
- Date: 2013
- Subjects: Poor performance -- Science
- Language: English
- Type: Thesis , Masters , M Ed
- Identifier: vital:18462 , http://hdl.handle.net/11260/d1008256
- Description: The purpose of this study was to investigate the factors contributing to senior secondary school learners’ poor performance in science subjects in the Mount Frere Education District of the Eastern Cape Province, South Africa. The literature analyses critically the existing knowledge based on factors contributing to poor performance of learners in science subjects and those factors that impact on learners’ positive attitudes towards science subjects. The study also identified literature on the following: motivational levels of science learners, teaching and learning strategies used in teaching science subjects, medium of instruction in the teaching and learning of science subjects, parental involvement in children’s learning, effects of lack of instructional materials on learner performance and learners’ attitudes towards science subjects. The study also examined the views of learners, teachers, Head of Department of sciences, parents and principals on factors contributing to poor performance of senior secondary school learners inscience subjects. The population for the study comprised of all principals, science teachers, science Head of Department, parents and science learners of the twenty six (26) senior secondary schools in the Mount Frere Education District. The principals, science teachers, science Head of Departments, parents of science learners and science learners in seven (7) senior secondary schools that offered science subjects were used as a sample in this study. The study employed the mixed method of quantitative and qualitative approaches. The research designs used were the survey and the case study. The instruments used were the questionnaires in which closed-ended questions were used to secure information and the interviews where open ended questions were used to collect data. The questionnaire as an instrument got tested in the pilot study to investigate the validity and reliability and also to identify possible deficiencies so as to rectify them. The responses were analyzed and presented in percentages using the Statistical Package for Social Science (SPSS) in the quantitative approach method of data analysis and in the qualitative data analysis process the researcher read through the data and became familiar with it and then identified the main themes and the next step was to examine the data in-depth and to provide detail descriptions of the participants’ words. The researcher also categorised and coded the data and then grouped them into themes and finally, interpreted the organised data into conclusion. The findings revealed that there was a lack of parental involvement, shortage of instructional materials, shortage of school laboratories, shortage of qualified science teachers and the learners’ negative attitudes towards science subjects. Recommendations were made concerning the above findings.
- Full Text:
- Date Issued: 2013
Beyond the threshold: explorations of liminality in literature. A book review
- Authors: Dass, Minesh
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142520 , vital:38087 , DOI: 10.1080/10131752.2013.783395
- Description: Beyond the Threshold: Explorations of Liminality in Literature, an edited collection of essays, is the culmination of research project on liminality done under the title “Poetics of boundaries and Hybridity”. This venture was undertaken in what is now known as the Research Unit Languages and Literature in the South African Context at North-West University. Some of the articles were initially presented at a conference on “Hybridity, Liminality and Boundaries” which was held in Potchefstroom from 30 June to 2 July 2005. Furthermore, shorter versions of some chapters have already been published in a special edition of Literator (Vol. 27. 1).
- Full Text:
- Date Issued: 2013
- Authors: Dass, Minesh
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142520 , vital:38087 , DOI: 10.1080/10131752.2013.783395
- Description: Beyond the Threshold: Explorations of Liminality in Literature, an edited collection of essays, is the culmination of research project on liminality done under the title “Poetics of boundaries and Hybridity”. This venture was undertaken in what is now known as the Research Unit Languages and Literature in the South African Context at North-West University. Some of the articles were initially presented at a conference on “Hybridity, Liminality and Boundaries” which was held in Potchefstroom from 30 June to 2 July 2005. Furthermore, shorter versions of some chapters have already been published in a special edition of Literator (Vol. 27. 1).
- Full Text:
- Date Issued: 2013
A psychobiographical study of William Wilberforce
- Authors: Daubermann, Bettina Pamela
- Date: 2013
- Subjects: Personality development
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9966 , http://hdl.handle.net/10948/d1020857 , http://hdl.handle.net/10948/d1021085
- Description: The proposed study is of a psychobiographical nature and employs a qualitative research approach. The individual that forms the subject of this study is William Wilberforce. A social activist most of his life, Wilberforce is best known for his voice and works behind the abolition of the slave trade in 1807 and the abolition of slavery in 1833. His ambitious nature, social eloquence and verbal intellect resulted in him being elected as a member of parliament in the House of Commons in England during the period 1780 to 1825. Transformed by the Christian faith in 1885, Wilberforce came to the realization he had received a calling from God to speak up for those who could not with a specific task set out before him which was to abolish slavery. It was the purpose of the present research to explore and describe Wilberforce’s psychological development across his life-span according to Carl Rogers’ (1961) personality theory of optimal development. Salient aspects of Wilberforce’s life were related and compared to components of the theory so as to explore and describe the degree of optimal development that Wilberforce reached at different points in his life and whether he could be described as a fully functioning person. According to Rogers’ theory William Wilberforce was chosen as the research subject for his historical contribution to mankind by his devotion to the moral enhancement of his country.
- Full Text:
- Date Issued: 2013
- Authors: Daubermann, Bettina Pamela
- Date: 2013
- Subjects: Personality development
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9966 , http://hdl.handle.net/10948/d1020857 , http://hdl.handle.net/10948/d1021085
- Description: The proposed study is of a psychobiographical nature and employs a qualitative research approach. The individual that forms the subject of this study is William Wilberforce. A social activist most of his life, Wilberforce is best known for his voice and works behind the abolition of the slave trade in 1807 and the abolition of slavery in 1833. His ambitious nature, social eloquence and verbal intellect resulted in him being elected as a member of parliament in the House of Commons in England during the period 1780 to 1825. Transformed by the Christian faith in 1885, Wilberforce came to the realization he had received a calling from God to speak up for those who could not with a specific task set out before him which was to abolish slavery. It was the purpose of the present research to explore and describe Wilberforce’s psychological development across his life-span according to Carl Rogers’ (1961) personality theory of optimal development. Salient aspects of Wilberforce’s life were related and compared to components of the theory so as to explore and describe the degree of optimal development that Wilberforce reached at different points in his life and whether he could be described as a fully functioning person. According to Rogers’ theory William Wilberforce was chosen as the research subject for his historical contribution to mankind by his devotion to the moral enhancement of his country.
- Full Text:
- Date Issued: 2013
Environmentally friendly dyeing and finishing
- Authors: Dayla, Mackraj
- Date: 2013
- Subjects: Dyes and dyeing -- Knit goods -- South Africa , Textile finishing -- South Africa , Bleaching industry -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10454 , http://hdl.handle.net/10948/d1020776
- Description: The textile industry in South Africa is a significant contributor to the chemical load that public wastewater treatment plants have to process, and the discharge of toxic substances, especially to the aquatic environment. In order to address this issue at factory level, the processes at a textile plant, JMV Textiles were chosen for investigation into the possibilities of minimization of discharges of harmful substances into the environment. The study followed the principles of cleaner production, and the processes that were investigated and revised were: The conventional peroxide bleaching process employed a peroxide stabilizer that did not biodegrade easily. The bleaching process was changed, so that the prevailing conditions in the fabric and dyebath facilitated bleaching without the addition of peroxide stabilizer, and also reduced the alkali and energy requirements. Polyester‐viscose fabric was pretreated by bleaching with hydrogen peroxide, which seemed to be unnecessarily rigorous, because polyester and viscose, unlike natural fibres, are relatively clean and have good whiteness in comparison with natural fibres. The proposed alternate pretreatment was a scour with detergent and alkali. The pretreatment for all polyester‐cotton fabrics was also a hydrogen peroxide bleach. Due to the ability of medium and dark shades to mask the natural tint of cotton fibres, a simpler alternate pretreatment, consisting of an alkaline scour with sequestering agent, was trialled. An unacceptable proportion of the dyeings on polyester was rejected for dye‐stains and dye‐marks. A possible solution exploited the properties of using the finishing auxiliary chemical to alleviate dye‐stains and dye‐marks during the dyeing stage, instead of using the chemical after dyeing. The highly toxic carrier that was used to facilitate level dyeing of polyester fibres that had unacceptable variation in their dyeing properties, was replaced by a less toxic carrier. The formulation for dyeing polyester was simplified to eliminate the auxiliary chemicals that were not essential to the dyeing process. Pale reactive dyed shades on cellulose and polyester‐cellulose were washed off only with hot water instead of detergent. The revised procedures consequential to the study, offered significant environmental benefits by reducing the concentration and volume of effluent produced, substituting a highly toxic carrier with a less toxic one and saving energy and water. Implementation of the suggested changes also offered financial benefits. The management of the factory, however, accepted and implemented some changes, but wanted further investigations for others and a phased approach to the other suggested changes.
- Full Text:
- Date Issued: 2013
- Authors: Dayla, Mackraj
- Date: 2013
- Subjects: Dyes and dyeing -- Knit goods -- South Africa , Textile finishing -- South Africa , Bleaching industry -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10454 , http://hdl.handle.net/10948/d1020776
- Description: The textile industry in South Africa is a significant contributor to the chemical load that public wastewater treatment plants have to process, and the discharge of toxic substances, especially to the aquatic environment. In order to address this issue at factory level, the processes at a textile plant, JMV Textiles were chosen for investigation into the possibilities of minimization of discharges of harmful substances into the environment. The study followed the principles of cleaner production, and the processes that were investigated and revised were: The conventional peroxide bleaching process employed a peroxide stabilizer that did not biodegrade easily. The bleaching process was changed, so that the prevailing conditions in the fabric and dyebath facilitated bleaching without the addition of peroxide stabilizer, and also reduced the alkali and energy requirements. Polyester‐viscose fabric was pretreated by bleaching with hydrogen peroxide, which seemed to be unnecessarily rigorous, because polyester and viscose, unlike natural fibres, are relatively clean and have good whiteness in comparison with natural fibres. The proposed alternate pretreatment was a scour with detergent and alkali. The pretreatment for all polyester‐cotton fabrics was also a hydrogen peroxide bleach. Due to the ability of medium and dark shades to mask the natural tint of cotton fibres, a simpler alternate pretreatment, consisting of an alkaline scour with sequestering agent, was trialled. An unacceptable proportion of the dyeings on polyester was rejected for dye‐stains and dye‐marks. A possible solution exploited the properties of using the finishing auxiliary chemical to alleviate dye‐stains and dye‐marks during the dyeing stage, instead of using the chemical after dyeing. The highly toxic carrier that was used to facilitate level dyeing of polyester fibres that had unacceptable variation in their dyeing properties, was replaced by a less toxic carrier. The formulation for dyeing polyester was simplified to eliminate the auxiliary chemicals that were not essential to the dyeing process. Pale reactive dyed shades on cellulose and polyester‐cellulose were washed off only with hot water instead of detergent. The revised procedures consequential to the study, offered significant environmental benefits by reducing the concentration and volume of effluent produced, substituting a highly toxic carrier with a less toxic one and saving energy and water. Implementation of the suggested changes also offered financial benefits. The management of the factory, however, accepted and implemented some changes, but wanted further investigations for others and a phased approach to the other suggested changes.
- Full Text:
- Date Issued: 2013
Investigating the problems experienced by virtual team members engaged in requirements elicitation
- Authors: De Abrew, Upuli Kanchana
- Date: 2013
- Subjects: Virtual work teams Virtual work teams -- South Africa System design System analysis
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1151 , http://hdl.handle.net/10962/d1007845
- Description: The constant acceleration in the rate of technological innovation, and the ever growing emphasis on the importance of information for competition has seen organisations around the world strive for the technologies that give them global customer reach. One of the most pervasive technological innovations developed is the internet, and its unique quality of being able to draw people from across the world together in one virtual space has given birth to the concept of virtual teams. Organisations have seized the advantages of such virtual teams to give them the cost and time reductions they need to stay competitive in the global marketplace. In the software industry, where product and service development is always a race against time, forward thinking software companies in the developed world have taken full advantage of the cost and time saving benefits that virtual teams have to offer. In addition, the rate of expansion of technology and software to support such teams is also growing exponentially, offering increasingly faster ways of virtual working. Despite the immense advantages offered by such teams, South African software development companies do not seem to engage in distributed work to any great degree. The importance of this research rests on the belief that South African software development companies will be unable to avoid engaging in distributed software development if they are to achieve and maintain competitiveness in the global marketplace. This research focuses on a sub-section of the software development process with a specific reference to South African software development. The requirements elicitation phase of software development is one of the initial stages of any software project. It is here that developers work with the users in order to identify requirements for the system to be built. It is acknowledged that other phases of distributed development also bring to bear their own problems, however, in the interests of scoping this research, only the requirements elicitation process is focused on. The research shows that most techniques of requirements elicitation can be adapted for use within the virtual environment, although each technique has its share of advantages and disadvantages. In addition, virtual team members experience problems during their general, day-to-day interactions, many of these arising from the dependence on technology for communication and task performance. The research identifies the problems in both categories, and develops a holistic model of virtual requirements elicitation to prevent or solve the problems experienced by virtual teams engaged in distributed requirements elicitation. The model is made up of three key frameworks, each of which prescribes actions to be taken to ensure the success of the virtual team within the requirements elicitation process. The model is verified through the testing of its critical success factors. Certain aspects of the model were adapted based on the findings of the study, but it was confirmed that the rationale behind the model is sound, indicating that it has the potential to solve the problems of virtual RE when implemented.
- Full Text:
- Date Issued: 2013
- Authors: De Abrew, Upuli Kanchana
- Date: 2013
- Subjects: Virtual work teams Virtual work teams -- South Africa System design System analysis
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1151 , http://hdl.handle.net/10962/d1007845
- Description: The constant acceleration in the rate of technological innovation, and the ever growing emphasis on the importance of information for competition has seen organisations around the world strive for the technologies that give them global customer reach. One of the most pervasive technological innovations developed is the internet, and its unique quality of being able to draw people from across the world together in one virtual space has given birth to the concept of virtual teams. Organisations have seized the advantages of such virtual teams to give them the cost and time reductions they need to stay competitive in the global marketplace. In the software industry, where product and service development is always a race against time, forward thinking software companies in the developed world have taken full advantage of the cost and time saving benefits that virtual teams have to offer. In addition, the rate of expansion of technology and software to support such teams is also growing exponentially, offering increasingly faster ways of virtual working. Despite the immense advantages offered by such teams, South African software development companies do not seem to engage in distributed work to any great degree. The importance of this research rests on the belief that South African software development companies will be unable to avoid engaging in distributed software development if they are to achieve and maintain competitiveness in the global marketplace. This research focuses on a sub-section of the software development process with a specific reference to South African software development. The requirements elicitation phase of software development is one of the initial stages of any software project. It is here that developers work with the users in order to identify requirements for the system to be built. It is acknowledged that other phases of distributed development also bring to bear their own problems, however, in the interests of scoping this research, only the requirements elicitation process is focused on. The research shows that most techniques of requirements elicitation can be adapted for use within the virtual environment, although each technique has its share of advantages and disadvantages. In addition, virtual team members experience problems during their general, day-to-day interactions, many of these arising from the dependence on technology for communication and task performance. The research identifies the problems in both categories, and develops a holistic model of virtual requirements elicitation to prevent or solve the problems experienced by virtual teams engaged in distributed requirements elicitation. The model is made up of three key frameworks, each of which prescribes actions to be taken to ensure the success of the virtual team within the requirements elicitation process. The model is verified through the testing of its critical success factors. Certain aspects of the model were adapted based on the findings of the study, but it was confirmed that the rationale behind the model is sound, indicating that it has the potential to solve the problems of virtual RE when implemented.
- Full Text:
- Date Issued: 2013
The relationship between psychological capital and psychological well-being
- Authors: De Andrade, Ruaan Kriel
- Date: 2013
- Subjects: Organizational sociology -- Research , Clinical health psychology , Psychology -- Management -- Social aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9412 , http://hdl.handle.net/10948/d1020096
- Description: A study of the available literature on Psychological WellQBeing and Positive Organisational Scholarship revealed that enormous potential existed for further research. This is a relatively new field with limited literature and research evidence available. It became very clear from the beginning that the relationships between these constructs could successfully be researched. It was therefore decided to embark on an academic research journey in order to contribute to the existing knowledge available on these constructs within the South African Private Healthcare Industry. This quantitative research was used to obtain more clarity about the relationships between the two constructs and to gather the responses from the research population. The research sample consisted of 152 nursing staff. Two questionnaires were integrated to develop the Nursing Psychological WellQBeing Questionnaire and consisted of i) PsyCap Questionnaire developed by Luthans, Youssef and Avolio2007, and ii) Psychological WellQBeing Questionnaire developed by Ryff 2000. A total of 152 nursing staff responded to an 87–item paperQbased questionnaire. Four research questions were formulated and covered the following: •The content, validity and portability of the measuring instruments; •The configuration of the various constructs; • Relationships between some of the variables . The content and the structure of the measuring instruments were assessed by means of Confirmatory Factor Analysis (CFA) and) Exploratory Factor Analyses (EFA). These assessments showed that the original measuring instruments are not portable to a culture which is different to the one where they were originally developed. The relationship between dimensions of Psychological WellQBeing and PsyCap sense of achievement and optimism is a significant finding. The significance of the findings of this study and the contribution that it makes to the existing theory is seen in the importance of the portability of measuring instruments. Recommendations in this regard have been made in Chapter 5. Various findings have also highlighted the relationships between Psychological WellQBeing and PsyCap. The importance of future research topics has been recommended.
- Full Text:
- Date Issued: 2013
- Authors: De Andrade, Ruaan Kriel
- Date: 2013
- Subjects: Organizational sociology -- Research , Clinical health psychology , Psychology -- Management -- Social aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9412 , http://hdl.handle.net/10948/d1020096
- Description: A study of the available literature on Psychological WellQBeing and Positive Organisational Scholarship revealed that enormous potential existed for further research. This is a relatively new field with limited literature and research evidence available. It became very clear from the beginning that the relationships between these constructs could successfully be researched. It was therefore decided to embark on an academic research journey in order to contribute to the existing knowledge available on these constructs within the South African Private Healthcare Industry. This quantitative research was used to obtain more clarity about the relationships between the two constructs and to gather the responses from the research population. The research sample consisted of 152 nursing staff. Two questionnaires were integrated to develop the Nursing Psychological WellQBeing Questionnaire and consisted of i) PsyCap Questionnaire developed by Luthans, Youssef and Avolio2007, and ii) Psychological WellQBeing Questionnaire developed by Ryff 2000. A total of 152 nursing staff responded to an 87–item paperQbased questionnaire. Four research questions were formulated and covered the following: •The content, validity and portability of the measuring instruments; •The configuration of the various constructs; • Relationships between some of the variables . The content and the structure of the measuring instruments were assessed by means of Confirmatory Factor Analysis (CFA) and) Exploratory Factor Analyses (EFA). These assessments showed that the original measuring instruments are not portable to a culture which is different to the one where they were originally developed. The relationship between dimensions of Psychological WellQBeing and PsyCap sense of achievement and optimism is a significant finding. The significance of the findings of this study and the contribution that it makes to the existing theory is seen in the importance of the portability of measuring instruments. Recommendations in this regard have been made in Chapter 5. Various findings have also highlighted the relationships between Psychological WellQBeing and PsyCap. The importance of future research topics has been recommended.
- Full Text:
- Date Issued: 2013