"Is more, less?" : insect-insect interactions in a biological control context using water hyacinth as a model
- Weyl, Philip Sebastian Richard
- Authors: Weyl, Philip Sebastian Richard
- Date: 2012
- Subjects: Water hyacinth -- South Africa -- Eastern Cape , Water hyacinth -- Biological control -- South Africa -- Eastern Cape , Insects as biological pest control agents , Miridae -- South Africa -- Eastern Cape , Beetles -- South Africa -- Eastern Cape , Competition (Biology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5724 , http://hdl.handle.net/10962/d1005410 , Water hyacinth -- South Africa -- Eastern Cape , Water hyacinth -- Biological control -- South Africa -- Eastern Cape , Insects as biological pest control agents , Miridae -- South Africa -- Eastern Cape , Beetles -- South Africa -- Eastern Cape , Competition (Biology)
- Description: Interactions between insects have been shown to be important regulators of population abundances and dynamics as well as drivers of spatial segregation and distribution. These are important aspects of the ecology of insects used in biological control and may have implications for the overall success of a particular programme. In the history of biological control there has been a tendency to release a suite of agents against a weed, which in some cases has increased the level of success, while in others little change has been observed. In most of these cases the implications of increasing the level of complexity of the system is not taken into account and there is little research on the effect of releasing another agent into the system. A brief meta-analysis was done on all the biological control programmes initiated in South Africa. Emphasis was placed on multi-species releases and the effects that overlapping niches were having on the number of agents responsible for the success of a programme. Where overlapping niches were present among agents released the number of agents responsible for success was lower than the number established. Water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach in South Africa has more arthropod agents released against it than anywhere else in the world, yet control has been variable. If the biology and host utilisation of all the agents against water hyacinth is considered, a definite overlap of niches is apparent in at least one life stage of all the agents. Therefore the probability of these insects interacting is high, especially if they are established at the same site in the field. Three of the insects released in South Africa have been selected to investigate possible interactions. They are Neochetina eichhorniae Warner, Neochetina bruchi Hustache and Eccritotarsus catarinensis (Carvalho). Y-tube olfactometer bioassays were used to measure responses of these insects to water hyacinth with prior feeding damage by either conspecifics or heterospecifics. This was done to determine whether olfactory cues played a role in host acceptability and avoidance of conspecifics or heterospecifics. The insects were given a choice between damaged and undamaged plants in various combinations. There was a significant preference for the undamaged plants when given a choice between undamaged and damaged plants. However when the insects were given a choice between two damaged plants there was no discrimination between heterospecific or conspecific damaged plants. This may indicate that there is little or no ecological cost for the insect to share a plant with other insects utilising a similar resource. Insect – insect interactions were investigated in a common garden plot experiment to measure the impact that pairwise combinations of the insect may have on their performance. There was a significant interaction between the mirid E. catarinensis and the weevil N. eichhorniae, with the weevil not performing as well when in combination with the mirid than when alone. Interestingly there was a negative interaction between the two weevil species when in combination, however it was impossible to determine which species was being affected if not both. None of the insects performed significantly better when in combination with another insect. A field study on Wriggleswade Dam in the Eastern Cape, South Africa was initiated to determine whether the relationship between the mirid E. catarinensis and the weevil N. eichhorniae could be determined in the field. The performance of the insects at the different sites in the field suggests that there was an interaction between the agents. This interaction did not limit the establishment of either insect at a site, but it did result in one insect dominating at a site over another. Interactions between the three species of insect tested in this thesis suggest that there are both negative and neutral relationships between them. A basic comparison between the insect performances from 15 sites around the country was done to determine if the spatial segregation observed in the field could be extrapolated to the natural South African situation. The interaction observed between N. eichhorniae and E. catarinensis does seem to extrapolate to the general South African situation where there is definite spatial segregation on a landscape level. The co–occurrence of the two Neochetina weevils at these sites suggests that the negative relationship observed between them in the common garden experiment does not extrapolate to the field. The results from this thesis suggest that the interactions between the agents tested would not limit establishment or have significant ramifications on performance. However, there may be spatial and temporal segregation of these species in the introduced range.
- Full Text:
- Date Issued: 2012
- Authors: Weyl, Philip Sebastian Richard
- Date: 2012
- Subjects: Water hyacinth -- South Africa -- Eastern Cape , Water hyacinth -- Biological control -- South Africa -- Eastern Cape , Insects as biological pest control agents , Miridae -- South Africa -- Eastern Cape , Beetles -- South Africa -- Eastern Cape , Competition (Biology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5724 , http://hdl.handle.net/10962/d1005410 , Water hyacinth -- South Africa -- Eastern Cape , Water hyacinth -- Biological control -- South Africa -- Eastern Cape , Insects as biological pest control agents , Miridae -- South Africa -- Eastern Cape , Beetles -- South Africa -- Eastern Cape , Competition (Biology)
- Description: Interactions between insects have been shown to be important regulators of population abundances and dynamics as well as drivers of spatial segregation and distribution. These are important aspects of the ecology of insects used in biological control and may have implications for the overall success of a particular programme. In the history of biological control there has been a tendency to release a suite of agents against a weed, which in some cases has increased the level of success, while in others little change has been observed. In most of these cases the implications of increasing the level of complexity of the system is not taken into account and there is little research on the effect of releasing another agent into the system. A brief meta-analysis was done on all the biological control programmes initiated in South Africa. Emphasis was placed on multi-species releases and the effects that overlapping niches were having on the number of agents responsible for the success of a programme. Where overlapping niches were present among agents released the number of agents responsible for success was lower than the number established. Water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach in South Africa has more arthropod agents released against it than anywhere else in the world, yet control has been variable. If the biology and host utilisation of all the agents against water hyacinth is considered, a definite overlap of niches is apparent in at least one life stage of all the agents. Therefore the probability of these insects interacting is high, especially if they are established at the same site in the field. Three of the insects released in South Africa have been selected to investigate possible interactions. They are Neochetina eichhorniae Warner, Neochetina bruchi Hustache and Eccritotarsus catarinensis (Carvalho). Y-tube olfactometer bioassays were used to measure responses of these insects to water hyacinth with prior feeding damage by either conspecifics or heterospecifics. This was done to determine whether olfactory cues played a role in host acceptability and avoidance of conspecifics or heterospecifics. The insects were given a choice between damaged and undamaged plants in various combinations. There was a significant preference for the undamaged plants when given a choice between undamaged and damaged plants. However when the insects were given a choice between two damaged plants there was no discrimination between heterospecific or conspecific damaged plants. This may indicate that there is little or no ecological cost for the insect to share a plant with other insects utilising a similar resource. Insect – insect interactions were investigated in a common garden plot experiment to measure the impact that pairwise combinations of the insect may have on their performance. There was a significant interaction between the mirid E. catarinensis and the weevil N. eichhorniae, with the weevil not performing as well when in combination with the mirid than when alone. Interestingly there was a negative interaction between the two weevil species when in combination, however it was impossible to determine which species was being affected if not both. None of the insects performed significantly better when in combination with another insect. A field study on Wriggleswade Dam in the Eastern Cape, South Africa was initiated to determine whether the relationship between the mirid E. catarinensis and the weevil N. eichhorniae could be determined in the field. The performance of the insects at the different sites in the field suggests that there was an interaction between the agents. This interaction did not limit the establishment of either insect at a site, but it did result in one insect dominating at a site over another. Interactions between the three species of insect tested in this thesis suggest that there are both negative and neutral relationships between them. A basic comparison between the insect performances from 15 sites around the country was done to determine if the spatial segregation observed in the field could be extrapolated to the natural South African situation. The interaction observed between N. eichhorniae and E. catarinensis does seem to extrapolate to the general South African situation where there is definite spatial segregation on a landscape level. The co–occurrence of the two Neochetina weevils at these sites suggests that the negative relationship observed between them in the common garden experiment does not extrapolate to the field. The results from this thesis suggest that the interactions between the agents tested would not limit establishment or have significant ramifications on performance. However, there may be spatial and temporal segregation of these species in the introduced range.
- Full Text:
- Date Issued: 2012
'Becoming citizens': young people making sense of citizenship on a South African community radio station youth show
- Karamagi, Sharon Benna Kyakyo
- Authors: Karamagi, Sharon Benna Kyakyo
- Date: 2012
- Subjects: Citizenship -- Study and teaching -- South Africa Youth -- Social conditions Community radio -- South Africa -- Grahamstown Grahamstown (South Africa) -- Economic conditions
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3444 , http://hdl.handle.net/10962/d1002898
- Description: This research set out to investigate the role that community radio can potentially play as a space in which young people engage with their own role as citizens and, in so doing, participate in discussions that seek to address social problems in a community divided by class, income, gender and race. The study examines how a local community radio station - Radio Grahamstown - developed a youth programme Y4Yin which the producers of the show and its audience came together to negotiate the meaning of citizenship. The study examines whether this interactive programme was able to function as something like a public sphere where in young people were able to develop a greater sense of agency, at least in the realm of citizenship. Using evidence gathered through focus group discussions with a group of young school-going leamers, interviews conducted with the producers of the show Y4Y, and drawing on Dahlgren's elaboration of a functional public sphere, the research concludes that the show provided a useful platform for Grahamstown high school students to develop their own notions of citizenship and to, at least partially and tentatively, build some 'bridges' across the vectors of socio-economic division in the town. However, the research also concludes that the Y4Y producers often failed to use a mode of address contemporary to the youth and often did not use production techniques congruent with young people's cultural tastes. This limited the programme's appeal and its potential as an enabler of discussion about notions of citizenship and as a platform for social bridging. In addition, because of the producers' control over the choice of topics put up for discussion, open interaction was more limited than could have been expected. In addition, the study also concludes that various limitations to the leamers' freedom of expression (including their fear that teachers might be listening in to the shows) inhibited the programme's role as a deliberative public sphere where issues could be aired, common ground found, and solutions discussed.
- Full Text:
- Date Issued: 2012
- Authors: Karamagi, Sharon Benna Kyakyo
- Date: 2012
- Subjects: Citizenship -- Study and teaching -- South Africa Youth -- Social conditions Community radio -- South Africa -- Grahamstown Grahamstown (South Africa) -- Economic conditions
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3444 , http://hdl.handle.net/10962/d1002898
- Description: This research set out to investigate the role that community radio can potentially play as a space in which young people engage with their own role as citizens and, in so doing, participate in discussions that seek to address social problems in a community divided by class, income, gender and race. The study examines how a local community radio station - Radio Grahamstown - developed a youth programme Y4Yin which the producers of the show and its audience came together to negotiate the meaning of citizenship. The study examines whether this interactive programme was able to function as something like a public sphere where in young people were able to develop a greater sense of agency, at least in the realm of citizenship. Using evidence gathered through focus group discussions with a group of young school-going leamers, interviews conducted with the producers of the show Y4Y, and drawing on Dahlgren's elaboration of a functional public sphere, the research concludes that the show provided a useful platform for Grahamstown high school students to develop their own notions of citizenship and to, at least partially and tentatively, build some 'bridges' across the vectors of socio-economic division in the town. However, the research also concludes that the Y4Y producers often failed to use a mode of address contemporary to the youth and often did not use production techniques congruent with young people's cultural tastes. This limited the programme's appeal and its potential as an enabler of discussion about notions of citizenship and as a platform for social bridging. In addition, because of the producers' control over the choice of topics put up for discussion, open interaction was more limited than could have been expected. In addition, the study also concludes that various limitations to the leamers' freedom of expression (including their fear that teachers might be listening in to the shows) inhibited the programme's role as a deliberative public sphere where issues could be aired, common ground found, and solutions discussed.
- Full Text:
- Date Issued: 2012
'God is my forest': Xhosa cultural values provide untapped opportunities for conservation
- Cocks, Michelle L, Dold, Anthony P, Vetter, Susan M
- Authors: Cocks, Michelle L , Dold, Anthony P , Vetter, Susan M
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141198 , vital:37952 , DOI: 10.4102/sajs.v108i5/6.880
- Description: In South Africa conservation is still largely framed in terms of Western scientific values, with a focus on material benefits to local communities, whilst little is known about the intangible values local people attach to nature and biodiversity. We explored the cultural, spiritual and emotional relationships with nature expressed by Xhosa people, within the MaputalandPondoland-Albany Hotspot, as well as the activities that mediate this relationship. A descriptive research approach was applied to document the emotions, meanings and values associated with landscape elements. This approach included group and individual interviews and ‘walk-in-the-woods’ interviews and participatory mapping exercises. Respondents portrayed a strong, although not always easily articulated, appreciation for nature, especially ihlathi lesiXhosa (‘Xhosa forest’, vegetation types within the Thicket Biome).
- Full Text:
- Date Issued: 2012
- Authors: Cocks, Michelle L , Dold, Anthony P , Vetter, Susan M
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141198 , vital:37952 , DOI: 10.4102/sajs.v108i5/6.880
- Description: In South Africa conservation is still largely framed in terms of Western scientific values, with a focus on material benefits to local communities, whilst little is known about the intangible values local people attach to nature and biodiversity. We explored the cultural, spiritual and emotional relationships with nature expressed by Xhosa people, within the MaputalandPondoland-Albany Hotspot, as well as the activities that mediate this relationship. A descriptive research approach was applied to document the emotions, meanings and values associated with landscape elements. This approach included group and individual interviews and ‘walk-in-the-woods’ interviews and participatory mapping exercises. Respondents portrayed a strong, although not always easily articulated, appreciation for nature, especially ihlathi lesiXhosa (‘Xhosa forest’, vegetation types within the Thicket Biome).
- Full Text:
- Date Issued: 2012
(Dis)allowances of lesbians’ sexual identities: Lesbian identity construction in racialised, classed, familial, and institutional spaces
- Gibson, Alexandra, Macleod, Catriona I
- Authors: Gibson, Alexandra , Macleod, Catriona I
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6222 , http://hdl.handle.net/10962/d1006536 , http://dx.doi.org/10.1177/0959353512459580
- Description: This article explores how lesbian identity construction is facilitated and constrained by the raced, classed, gendered, familial, and geographical spaces that women occupy. We present a narrative-discursive analysis of eight lesbians’ stories of sexuality, told within a historically white university in South Africa. Three interpretative repertoires that emerged in the narratives are discussed. The ‘disallowance of lesbian identity in particular racialised and class-based spaces’ repertoire, deployed by black lesbians only, was used to account for their de-emphasis of a lesbian identity through the invocation of a threat of danger and stereotyping. The ‘disjuncture of the (heterosexual) family and lesbian identity’ repertoire emphasised how the expectation of support and care within a family does not necessarily extend to acceptance of a lesbian identity.
- Full Text:
- Date Issued: 2012
- Authors: Gibson, Alexandra , Macleod, Catriona I
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6222 , http://hdl.handle.net/10962/d1006536 , http://dx.doi.org/10.1177/0959353512459580
- Description: This article explores how lesbian identity construction is facilitated and constrained by the raced, classed, gendered, familial, and geographical spaces that women occupy. We present a narrative-discursive analysis of eight lesbians’ stories of sexuality, told within a historically white university in South Africa. Three interpretative repertoires that emerged in the narratives are discussed. The ‘disallowance of lesbian identity in particular racialised and class-based spaces’ repertoire, deployed by black lesbians only, was used to account for their de-emphasis of a lesbian identity through the invocation of a threat of danger and stereotyping. The ‘disjuncture of the (heterosexual) family and lesbian identity’ repertoire emphasised how the expectation of support and care within a family does not necessarily extend to acceptance of a lesbian identity.
- Full Text:
- Date Issued: 2012
4-Azidoaniline-based electropolymer as a building block for functionalisation of conductive surfaces
- Coates, Megan, Elamari, Hichem, Girard, Christian, Griveau, Sophie, Nyokong, Tebello, Bedioui, Fethi
- Authors: Coates, Megan , Elamari, Hichem , Girard, Christian , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244404 , vital:51254 , xlink:href="https://doi.org/10.1016/j.jelechem.2012.01.001"
- Description: We propose in this work to compare three approaches using 4-azidoaniline combined with “click” chemistry and electrochemistry to anchor ferrocene moieties at glassy carbon surfaces. The immobilisation of a newly synthesised molecule, 4-(4-ferrocenyl-1H-1,2,3-triazol-1-yl)aniline, through direct electropolymerisation or via in situ diazotization followed by electrografting is studied by analysing the samples by XPS and electrochemistry.
- Full Text:
- Date Issued: 2012
4-Azidoaniline-based electropolymer as a building block for functionalisation of conductive surfaces
- Authors: Coates, Megan , Elamari, Hichem , Girard, Christian , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244404 , vital:51254 , xlink:href="https://doi.org/10.1016/j.jelechem.2012.01.001"
- Description: We propose in this work to compare three approaches using 4-azidoaniline combined with “click” chemistry and electrochemistry to anchor ferrocene moieties at glassy carbon surfaces. The immobilisation of a newly synthesised molecule, 4-(4-ferrocenyl-1H-1,2,3-triazol-1-yl)aniline, through direct electropolymerisation or via in situ diazotization followed by electrografting is studied by analysing the samples by XPS and electrochemistry.
- Full Text:
- Date Issued: 2012
A baculovirus-mediated expression system for the analysis of HaSV RNA packaging
- Authors: Mendes, Adriano
- Date: 2012
- Subjects: RNA , Baculoviruses , Helicoverpa armigera , Plasmids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4025 , http://hdl.handle.net/10962/d1004085 , RNA , Baculoviruses , Helicoverpa armigera , Plasmids
- Description: The Helicoverpa armigera stunt virus (HaSV) is a member of a family of small nonenveloped (+) ssRNA insect viruses currently known as the Tetraviridae. This family is unique in terms of the T=4 quasi-symmetry of its capsid particles and the unusually narrow host range and tissue tropism. Assembly of tetraviral particles has been well characterised and involves the combination of 240 copies of a single capsid precursor protein (VCap) into a procapsid followed by autoproteolytic cleavage to yield the major (β) and minor (γ) capsid subunits within the mature particle. HaSV has two genomic RNAs, RNA 1 encoding the replicase and RNA 2 encoding VCap and p17, the ORF of which lies upstream of and overlaping with the 5’ end of the VCap ORF. Prior to this study, Vlok (2009) used a plasmid expression system to study RNA packaging in HaSV VLPs assembled in Spodoptera frugiperda 9 (Sf9) cells co-expressing p17 and VCap. The study showed that the p17 ORF was required for the packaging of RNA 2 during capsid assembly but it was unclear whether p17 expression was required for packaging. In addition, expression from the transfected plasmids was sub-optimal affecting both the yield of VLPs and the detection of p17. The aim of this study was to use the plasmid system to test whether p17 expression was required for plasmid-derived VLP RNA packaging and then develop a baculovirus-mediated system to test this hypothesis. By using a plasmid in which the start codon of p17 was mutated, it was shown that p17 expression was required for RNA 2 packaging into plasmid-VLPs. For the baculovirus system, four recombinant baculoviruses based upon the pFastBac Dual expression system, were constructed. These included Bac20, expressing wild type RNA 2, Bac21, RNA 2 with p17 silenced, Bac23, RNA 2 and p17 expressed on a separate transcript and Bac24, RNA 2 with p17 silenced plus p17 expressed on a separate transcript. Assembly of VLPs was more efficient using the baculovirus expression system and p17 expression was observed in cells infected with Bac20, Bac23 and Bac24, but not Bac21. In contrast to the plasmid-VLPs, bac-VLPs did not require p17 for the encapsidation of RNA 2. In addition to RNA 2, Bac23 and Bac24 packaged the p17 mRNA transcribed separately from RNA 2. This insinuated that bac-VLPs may be packaging RNA non-selectively. It was proposed that p17 may play a role in packaging in an RNA-limiting environment (plasmid system) but functioned differently when viral RNA was in excess (baculovirus system). This data points to the importance of developing a replication system for the analysis of the packaging pathways of these viruses and this study has laid down the foundations for such a system in which RNA 1 and RNA 2 can be introduced into a single cell by means of a single recombinant virus.
- Full Text:
- Date Issued: 2012
- Authors: Mendes, Adriano
- Date: 2012
- Subjects: RNA , Baculoviruses , Helicoverpa armigera , Plasmids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4025 , http://hdl.handle.net/10962/d1004085 , RNA , Baculoviruses , Helicoverpa armigera , Plasmids
- Description: The Helicoverpa armigera stunt virus (HaSV) is a member of a family of small nonenveloped (+) ssRNA insect viruses currently known as the Tetraviridae. This family is unique in terms of the T=4 quasi-symmetry of its capsid particles and the unusually narrow host range and tissue tropism. Assembly of tetraviral particles has been well characterised and involves the combination of 240 copies of a single capsid precursor protein (VCap) into a procapsid followed by autoproteolytic cleavage to yield the major (β) and minor (γ) capsid subunits within the mature particle. HaSV has two genomic RNAs, RNA 1 encoding the replicase and RNA 2 encoding VCap and p17, the ORF of which lies upstream of and overlaping with the 5’ end of the VCap ORF. Prior to this study, Vlok (2009) used a plasmid expression system to study RNA packaging in HaSV VLPs assembled in Spodoptera frugiperda 9 (Sf9) cells co-expressing p17 and VCap. The study showed that the p17 ORF was required for the packaging of RNA 2 during capsid assembly but it was unclear whether p17 expression was required for packaging. In addition, expression from the transfected plasmids was sub-optimal affecting both the yield of VLPs and the detection of p17. The aim of this study was to use the plasmid system to test whether p17 expression was required for plasmid-derived VLP RNA packaging and then develop a baculovirus-mediated system to test this hypothesis. By using a plasmid in which the start codon of p17 was mutated, it was shown that p17 expression was required for RNA 2 packaging into plasmid-VLPs. For the baculovirus system, four recombinant baculoviruses based upon the pFastBac Dual expression system, were constructed. These included Bac20, expressing wild type RNA 2, Bac21, RNA 2 with p17 silenced, Bac23, RNA 2 and p17 expressed on a separate transcript and Bac24, RNA 2 with p17 silenced plus p17 expressed on a separate transcript. Assembly of VLPs was more efficient using the baculovirus expression system and p17 expression was observed in cells infected with Bac20, Bac23 and Bac24, but not Bac21. In contrast to the plasmid-VLPs, bac-VLPs did not require p17 for the encapsidation of RNA 2. In addition to RNA 2, Bac23 and Bac24 packaged the p17 mRNA transcribed separately from RNA 2. This insinuated that bac-VLPs may be packaging RNA non-selectively. It was proposed that p17 may play a role in packaging in an RNA-limiting environment (plasmid system) but functioned differently when viral RNA was in excess (baculovirus system). This data points to the importance of developing a replication system for the analysis of the packaging pathways of these viruses and this study has laid down the foundations for such a system in which RNA 1 and RNA 2 can be introduced into a single cell by means of a single recombinant virus.
- Full Text:
- Date Issued: 2012
A baseline for information security knowledge for end users
- Authors: Boshoff, Ryno
- Date: 2012
- Subjects: Data protection -- Management , Computer security -- Management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9808 , http://hdl.handle.net/10948/d1013260
- Description: Information plays a vast contributing role to all resources within an organisation. Organisations should recognise the importance of information and implement information security controls to protect their information as this will ensure that the organisation‟s information retains its confidentiality, integrity and availability. Information security controls, which are the means of managing information risks, rely heavily on the user‟s knowledge regarding the use of these controls for their effectiveness, and as such, users should be educated in order to maximise effectiveness of these controls. Current information security educational programmes are created without necessarily taking into account the target audience, who comprises of all employees, stakeholders, suppliers, third parties, customers or other external parties or third party that requires access to the organisation‟s information. This results in programmes that are not linguistically appropriate; or that present knowledge at an inappropriate level for the target audience. This could leave users bored or confused, without successfully changing their behaviour or improving knowledge. This dissertation identifies a baseline for information security knowledge targeted at end users. This was done by means of a Delphi Study, where a profile of “generic” end users comprised of information security topics and concepts were rated by experts from the field of information security education. This resulted in the elimination of inappropriate topics and concepts and retaining the relevant and appropriate aspects. This baseline for information security knowledge can be characterised as a minimum standard that everybody should be educated on as an introductory or refresher course. This can also serve as the foundation phase to educate end users with knowledge of the basic topics and concepts to enable them to fulfil their responsibilities in order to protect information. If needed, topics and concepts could be added to the baseline for information security knowledge for specialised target audiences (e.g. specialised End Users, ICT Staff or Top Management).
- Full Text:
- Date Issued: 2012
- Authors: Boshoff, Ryno
- Date: 2012
- Subjects: Data protection -- Management , Computer security -- Management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9808 , http://hdl.handle.net/10948/d1013260
- Description: Information plays a vast contributing role to all resources within an organisation. Organisations should recognise the importance of information and implement information security controls to protect their information as this will ensure that the organisation‟s information retains its confidentiality, integrity and availability. Information security controls, which are the means of managing information risks, rely heavily on the user‟s knowledge regarding the use of these controls for their effectiveness, and as such, users should be educated in order to maximise effectiveness of these controls. Current information security educational programmes are created without necessarily taking into account the target audience, who comprises of all employees, stakeholders, suppliers, third parties, customers or other external parties or third party that requires access to the organisation‟s information. This results in programmes that are not linguistically appropriate; or that present knowledge at an inappropriate level for the target audience. This could leave users bored or confused, without successfully changing their behaviour or improving knowledge. This dissertation identifies a baseline for information security knowledge targeted at end users. This was done by means of a Delphi Study, where a profile of “generic” end users comprised of information security topics and concepts were rated by experts from the field of information security education. This resulted in the elimination of inappropriate topics and concepts and retaining the relevant and appropriate aspects. This baseline for information security knowledge can be characterised as a minimum standard that everybody should be educated on as an introductory or refresher course. This can also serve as the foundation phase to educate end users with knowledge of the basic topics and concepts to enable them to fulfil their responsibilities in order to protect information. If needed, topics and concepts could be added to the baseline for information security knowledge for specialised target audiences (e.g. specialised End Users, ICT Staff or Top Management).
- Full Text:
- Date Issued: 2012
A brain-compatible approach to the presentation of cyber security educational material
- Authors: Reid, Rayne
- Date: 2012
- Subjects: Data protection -- Management , Computer security -- Management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9819 , http://hdl.handle.net/10948/d1019895
- Description: Information is an extremely important asset in modern society. It is used in most daily activities and transactions, and, thus, the importance of information is acknowledged by both organisational and private home information users. Unfortunately, as with any asset, there are often threats to this asset and, therefore, an information security solution is required to protect information against potential threats. Human beings play a major role in the implementation and governing of an entire information security process and, therefore, they have responsibilities in this regard. Thus, the effectiveness of any information security solutions in either an organisational or a private context is dependent on the human beings involved in the process. Accordingly, if these human beings are either unaware or not knowledgeable about their roles in the security solution they become the weak link in the information security solutions and, thus, it is essential that all these information users be educated in order to combat any threats to the information security. Many of the current information security education programmes and materials are not effective, possibly because the majority of these current approaches have been designed without using a sound pedagogical theory. In addition, many of these programmes also only target organisational users. This, in turn, is problematic as information security education is required by everybody, organisational and private information users alike. This dissertation addressed the lack of a pedagogical basis in the designing of information security educational courses suited to an extremely broad target audience. Accordingly, the dissertation set out to demonstrate how a pedagogy, which is broadly used and accepted for a diverse target audience of learners, could be applied to the design of the presentation of a web based, cyber security educational courses.
- Full Text:
- Date Issued: 2012
- Authors: Reid, Rayne
- Date: 2012
- Subjects: Data protection -- Management , Computer security -- Management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9819 , http://hdl.handle.net/10948/d1019895
- Description: Information is an extremely important asset in modern society. It is used in most daily activities and transactions, and, thus, the importance of information is acknowledged by both organisational and private home information users. Unfortunately, as with any asset, there are often threats to this asset and, therefore, an information security solution is required to protect information against potential threats. Human beings play a major role in the implementation and governing of an entire information security process and, therefore, they have responsibilities in this regard. Thus, the effectiveness of any information security solutions in either an organisational or a private context is dependent on the human beings involved in the process. Accordingly, if these human beings are either unaware or not knowledgeable about their roles in the security solution they become the weak link in the information security solutions and, thus, it is essential that all these information users be educated in order to combat any threats to the information security. Many of the current information security education programmes and materials are not effective, possibly because the majority of these current approaches have been designed without using a sound pedagogical theory. In addition, many of these programmes also only target organisational users. This, in turn, is problematic as information security education is required by everybody, organisational and private information users alike. This dissertation addressed the lack of a pedagogical basis in the designing of information security educational courses suited to an extremely broad target audience. Accordingly, the dissertation set out to demonstrate how a pedagogy, which is broadly used and accepted for a diverse target audience of learners, could be applied to the design of the presentation of a web based, cyber security educational courses.
- Full Text:
- Date Issued: 2012
A case study describing factors perceived to be impacting staff satisfaction amongst health care professionals at the East London Hospital complex
- Authors: Galo, Luntu
- Date: 2012
- Subjects: Medical personnel -- Job satisfaction -- South Africa -- Case studies Medical personnel -- Job stress -- South Africa -- Case studies Medical personnel -- South Africa -- Attitudes -- Case studies Hospitals -- South Africa -- Administration Health services administration -- South Africa Health planning -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:784 , http://hdl.handle.net/10962/d1003905
- Description: This thesis was born from a concern the researcher had with regard to negative reports in the media emanating from 4 babies that died at Cecilia Makiwane Hospital Peadiatric ICU unit due to power supply failure. The most significant of these negative reports was in 2007 when the Daily Dispatch ran a series of articles regarding what they termed avoidable deaths over the last 14 years. The ease with which staff communicated with the media together with the high absenteeism rate and high turnover was a cause for concern. When the researcher analysed the history of the problem, it immerged from the respondents’ responses that the rationalistion process undertaken by the Eastern Cape Department of Health (ECDoH) was a significant root cause to the problem. The literature review focused on three areas viz.: Organisational Culture, Organisational Change, Foundations of Satisfaction. This focus was used to confine the problem to a manageable project but secondly each of the aspects are interwoven. Routledge (2010) notes that culture is the reflection of the values advocated by a founder or leader by way of his/her day to day actions. This is done by the leader creating a perception or viewpoint that assists the employees to achieve the organisation’s mission, vision and goals. In any organisation change is a constant and it needs to be effectively managed. With government institutions like the East London Hospital Complex (ELHC) directives come from the top and are implemented by an unprepared and untrained leadership and management cadre and clear communication of vision and objective of the desired outcomes never happens. The aim of the research was to: describe the existing Organisational Culture present at ELHC (Perform an organisational diagnosis); describe the impact of change (rationalisation) and to analyze why there was such a high staff turnover. It is clear from the results of the survey conducted that significant dissatisfaction prevailed relating to how the institution was managed. Dissatisfaction amongst the health professionals was general but also specific to the following: leadership and management issues, fairness, remuneration and lack of resources. The recommendations therefore focused on developing management and leadership within the proposal of Dubrin’s model (2001).
- Full Text:
- Date Issued: 2012
- Authors: Galo, Luntu
- Date: 2012
- Subjects: Medical personnel -- Job satisfaction -- South Africa -- Case studies Medical personnel -- Job stress -- South Africa -- Case studies Medical personnel -- South Africa -- Attitudes -- Case studies Hospitals -- South Africa -- Administration Health services administration -- South Africa Health planning -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:784 , http://hdl.handle.net/10962/d1003905
- Description: This thesis was born from a concern the researcher had with regard to negative reports in the media emanating from 4 babies that died at Cecilia Makiwane Hospital Peadiatric ICU unit due to power supply failure. The most significant of these negative reports was in 2007 when the Daily Dispatch ran a series of articles regarding what they termed avoidable deaths over the last 14 years. The ease with which staff communicated with the media together with the high absenteeism rate and high turnover was a cause for concern. When the researcher analysed the history of the problem, it immerged from the respondents’ responses that the rationalistion process undertaken by the Eastern Cape Department of Health (ECDoH) was a significant root cause to the problem. The literature review focused on three areas viz.: Organisational Culture, Organisational Change, Foundations of Satisfaction. This focus was used to confine the problem to a manageable project but secondly each of the aspects are interwoven. Routledge (2010) notes that culture is the reflection of the values advocated by a founder or leader by way of his/her day to day actions. This is done by the leader creating a perception or viewpoint that assists the employees to achieve the organisation’s mission, vision and goals. In any organisation change is a constant and it needs to be effectively managed. With government institutions like the East London Hospital Complex (ELHC) directives come from the top and are implemented by an unprepared and untrained leadership and management cadre and clear communication of vision and objective of the desired outcomes never happens. The aim of the research was to: describe the existing Organisational Culture present at ELHC (Perform an organisational diagnosis); describe the impact of change (rationalisation) and to analyze why there was such a high staff turnover. It is clear from the results of the survey conducted that significant dissatisfaction prevailed relating to how the institution was managed. Dissatisfaction amongst the health professionals was general but also specific to the following: leadership and management issues, fairness, remuneration and lack of resources. The recommendations therefore focused on developing management and leadership within the proposal of Dubrin’s model (2001).
- Full Text:
- Date Issued: 2012
A case study of Bigodi Wetland Sanctuary as a community driven Community-Based Natural Resource Management initiative : maintaining livelihoods and wetland health
- Authors: Gosling, Amanda Karen
- Date: 2012
- Subjects: Wetland conservation -- Uganda , Wetland ecology -- Uganda , Natural resources management areas -- Uganda , Rural development -- Uganda
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4752 , http://hdl.handle.net/10962/d1007065 , Wetland conservation -- Uganda , Wetland ecology -- Uganda , Natural resources management areas -- Uganda , Rural development -- Uganda
- Description: Community-Based Natural Resource Management (CBNRM) is considered a win-win approach to reconcile conservation with natural resource use. CBNRM aims to accomplish conservation whilst prioritising development and contributing to poverty alleviation. This study analysed the different components of a CBNRM initiative, Bigodi Wetland Sanctuary (BWS), located in western Uganda. The study was carried out by interviewing the managing committee members (n= 8) as well as local households (n= 68) regarding the manner in which the project works, and the associated benefits and constraints. The main management issues recognised were a lack of monitoring and committee cohesiveness. The information gathered through the household survey enabled the calculation of the value of local livelihood options. This was done on the premise that conservation is better accepted when land users realise the economic value of natural resources. The average annual value of household livelihoods was represented by 30% crop production, 57% natural resource use, and 13% livestock. Lastly, wetland assessments were performed using the WET-Health and WET-EcoServices methodologies from the Wetland Management Series. These assessments indicated that the impacts of local livelihoods on the wetland were currently low but potential issues could arise with the increasing human population density. Ultimately, BWS presents both environmental and social costs and benefits. With a detailed and interdisciplinary method specific recommendations of improvement can be made to reduce such costs and further reconcile the conservation of Bigodi Wetland with local natural resource use..
- Full Text:
- Date Issued: 2012
- Authors: Gosling, Amanda Karen
- Date: 2012
- Subjects: Wetland conservation -- Uganda , Wetland ecology -- Uganda , Natural resources management areas -- Uganda , Rural development -- Uganda
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4752 , http://hdl.handle.net/10962/d1007065 , Wetland conservation -- Uganda , Wetland ecology -- Uganda , Natural resources management areas -- Uganda , Rural development -- Uganda
- Description: Community-Based Natural Resource Management (CBNRM) is considered a win-win approach to reconcile conservation with natural resource use. CBNRM aims to accomplish conservation whilst prioritising development and contributing to poverty alleviation. This study analysed the different components of a CBNRM initiative, Bigodi Wetland Sanctuary (BWS), located in western Uganda. The study was carried out by interviewing the managing committee members (n= 8) as well as local households (n= 68) regarding the manner in which the project works, and the associated benefits and constraints. The main management issues recognised were a lack of monitoring and committee cohesiveness. The information gathered through the household survey enabled the calculation of the value of local livelihood options. This was done on the premise that conservation is better accepted when land users realise the economic value of natural resources. The average annual value of household livelihoods was represented by 30% crop production, 57% natural resource use, and 13% livestock. Lastly, wetland assessments were performed using the WET-Health and WET-EcoServices methodologies from the Wetland Management Series. These assessments indicated that the impacts of local livelihoods on the wetland were currently low but potential issues could arise with the increasing human population density. Ultimately, BWS presents both environmental and social costs and benefits. With a detailed and interdisciplinary method specific recommendations of improvement can be made to reduce such costs and further reconcile the conservation of Bigodi Wetland with local natural resource use..
- Full Text:
- Date Issued: 2012
A comparative analysis of anti-corruption legislation and anti-corruption agencies in the Eastern Cape and Northern Cape provices : a governance perspective
- Authors: Majila, Victoria Thozama
- Date: 2012
- Subjects: Political corruption -- South Africa , Misconduct in office -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8179 , http://hdl.handle.net/10948/2117 , Political corruption -- South Africa , Misconduct in office -- South Africa
- Description: This thesis analysed and compared the effectiveness of the anti-corruption legislation and anti-corruption agencies in the Eastern Cape and Northern Cape provinces. The thesis consists of six chapters. This study is based on the assumption that the struggle against corruption is best approached by developing a system of laws, institutions and supporting practices which promote integrity and make corrupt conduct a high-risk activity. It is imperative that a systemic approach is embarked upon in order to address the manner in which the major institutions and processes of the state are conquered and exploited by corrupt individuals and groups. With the magnitude in which hurdles exist that hamper the effectiveness of the country's anti-corruption legislation and anti-corruption agencies; South Africa is incapable of curbing corruption. With the purpose to determine a desired state of affairs, characteristics of effective anti-corruption agencies and anti-corruption legislation were presented. These served as a yardstick in measuring how effective such agencies and legislation are in South Africa. Reasons for failure of agencies and legislation are discussed. After discussing types of anti-corruption agencies, those that perform better than ix others were identified. Through literature review, the status quo concerning anti-corruption initiatives in South Africa was assessed. It was revealed that the level of the success of South African anti-corruption agencies and legislation has been limited. In the case of anti-corruption agencies, weaknesses such as fragmentation; insufficient coordination; poor delineation of responsibility; and assimilation of corruption work into a broader mandate were identified as major causes. Measures that are needed, such as informed citizens; a need to foster and sustain high levels of professional and ethically imbued civil servants; and legislation that supports the transition towards a corruption-free society that are needed to complement implementation of anti-corruption legislation, were also recognised. Ways of addressing such shortcomings that the writers identified are also presented. The methodology and design followed in the study are described. This is followed by the analysis and interpretation of the survey. The research findings are then presented. Based on the findings a number of recommendations that would assist in improving the effectiveness of anticorruption agencies and anti-corruption legislation are made. Flowing from the discussion of effective anti-corruption models that were identified by literature a model that would be ideal for South Africa is recommended.
- Full Text:
- Date Issued: 2012
- Authors: Majila, Victoria Thozama
- Date: 2012
- Subjects: Political corruption -- South Africa , Misconduct in office -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8179 , http://hdl.handle.net/10948/2117 , Political corruption -- South Africa , Misconduct in office -- South Africa
- Description: This thesis analysed and compared the effectiveness of the anti-corruption legislation and anti-corruption agencies in the Eastern Cape and Northern Cape provinces. The thesis consists of six chapters. This study is based on the assumption that the struggle against corruption is best approached by developing a system of laws, institutions and supporting practices which promote integrity and make corrupt conduct a high-risk activity. It is imperative that a systemic approach is embarked upon in order to address the manner in which the major institutions and processes of the state are conquered and exploited by corrupt individuals and groups. With the magnitude in which hurdles exist that hamper the effectiveness of the country's anti-corruption legislation and anti-corruption agencies; South Africa is incapable of curbing corruption. With the purpose to determine a desired state of affairs, characteristics of effective anti-corruption agencies and anti-corruption legislation were presented. These served as a yardstick in measuring how effective such agencies and legislation are in South Africa. Reasons for failure of agencies and legislation are discussed. After discussing types of anti-corruption agencies, those that perform better than ix others were identified. Through literature review, the status quo concerning anti-corruption initiatives in South Africa was assessed. It was revealed that the level of the success of South African anti-corruption agencies and legislation has been limited. In the case of anti-corruption agencies, weaknesses such as fragmentation; insufficient coordination; poor delineation of responsibility; and assimilation of corruption work into a broader mandate were identified as major causes. Measures that are needed, such as informed citizens; a need to foster and sustain high levels of professional and ethically imbued civil servants; and legislation that supports the transition towards a corruption-free society that are needed to complement implementation of anti-corruption legislation, were also recognised. Ways of addressing such shortcomings that the writers identified are also presented. The methodology and design followed in the study are described. This is followed by the analysis and interpretation of the survey. The research findings are then presented. Based on the findings a number of recommendations that would assist in improving the effectiveness of anticorruption agencies and anti-corruption legislation are made. Flowing from the discussion of effective anti-corruption models that were identified by literature a model that would be ideal for South Africa is recommended.
- Full Text:
- Date Issued: 2012
A comparative analysis of factors affecting the purchasing decisions of cleaning rag buyers in the Eastern Cape
- Authors: Shearer, David Charcles
- Date: 2012
- Subjects: Purchasing -- Decision making , Consumer behavior -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8898 , http://hdl.handle.net/10948/d1020928
- Description: The objectives of this research project were to identify and compare factors that influence the purchasing decisions of Multifibres’ customers active in each channel. Multifibres manufactures and distributes industrial cleaning rags to three channels or client categories, these being industrial resellers, industrial end-users and the walk-in customers. An extensive literature review revealed that purchasing decisions are influenced by, amongst other factors, the buyer’s role, the internal cognitive processes of the buyer, as well as factors present in the buyer’s business and external environment. An empirical study was conducted utilising in-depth interviews. The most prevalent, emergent themes that buyers attached the greatest weight to when purchasing cleaning rags were: price; quality; service; relationships; and, convenience. These factors were probed, analysed and compared, based on each buyer category’s unique set of characteristics. When motivating their purchasing preferences, resellers emphasised the importance of the business relationship and trust as being paramount, while end-users viewed price and service as the most important factors. Walk-in customers valued the combination of price and convenience as the most important reasons influencing their purchasing decisions.
- Full Text:
- Date Issued: 2012
- Authors: Shearer, David Charcles
- Date: 2012
- Subjects: Purchasing -- Decision making , Consumer behavior -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8898 , http://hdl.handle.net/10948/d1020928
- Description: The objectives of this research project were to identify and compare factors that influence the purchasing decisions of Multifibres’ customers active in each channel. Multifibres manufactures and distributes industrial cleaning rags to three channels or client categories, these being industrial resellers, industrial end-users and the walk-in customers. An extensive literature review revealed that purchasing decisions are influenced by, amongst other factors, the buyer’s role, the internal cognitive processes of the buyer, as well as factors present in the buyer’s business and external environment. An empirical study was conducted utilising in-depth interviews. The most prevalent, emergent themes that buyers attached the greatest weight to when purchasing cleaning rags were: price; quality; service; relationships; and, convenience. These factors were probed, analysed and compared, based on each buyer category’s unique set of characteristics. When motivating their purchasing preferences, resellers emphasised the importance of the business relationship and trust as being paramount, while end-users viewed price and service as the most important factors. Walk-in customers valued the combination of price and convenience as the most important reasons influencing their purchasing decisions.
- Full Text:
- Date Issued: 2012
A comparative analysis of the enforcement of market abuse provisions
- Authors: Chitimira, Howard
- Date: 2012
- Subjects: Corporation law -- South Africa , Insider trading in securities -- South Africa , Securities -- South Africa , Efficient market theory , Securities fraud
- Language: English
- Type: Thesis , Doctoral , LLD
- Identifier: vital:10240 , http://hdl.handle.net/10948/d1015008
- Description: Market abuse practices may directly or indirectly give rise to diverse problems such as inaccurate stock market prices, low public investor confidence, reduced market integrity and poor efficiency in the affected financial markets. This thesis reveals that three major forms of market abuse, namely insider trading, prohibited trading practices (trade-based market manipulation) and the making or publication of false, misleading or deceptive statements, promises and forecasts relating to listed securities (disclosure-based market manipulation) are prohibited in South Africa. However, although South Africa has had market abuse legislation for about 30 years, and must be commended for its great effort to enhance market integrity by combating market abuse practices, the enforcement of such legislation is still problematic. Moreover, in spite of the fact that there is no empirical data or accurate figures quantifying the occurrence and extent of market abuse activities in the South African financial markets, this thesis submits that market abuse practices are still to be completely eradicated. Accordingly, this thesis suggests that the aforementioned problem might have been aggravated by inter alia, various gaps, flaws and/or inconsistent implementation and enforcement of the market abuse legislation in South Africa. To this end, the anti-market abuse enforcement framework under the Securities Services Act 36 of 2004 is analysed to investigate its adequacy. The co-operation and role of the Financial Services Board, the courts, the Directorate of Market Abuse and other relevant stakeholders is also examined and discussed. Moreover, the co-operation between the Financial Services Board and similar international agencies is discussed to gauge its effectiveness in relation to the combating of cross-border market abuse practices. The adequacy of the awareness and preventative measures in place to curb market abuse practices is also investigated to determine whether such measures are robust enough to combat other new challenges that were posed by the 2007 to 2009 global financial crisis. Furthermore, a comparative analysis is undertaken of the enforcement of the market abuse prohibition in other jurisdictions, namely the United States of America, the United Kingdom, the European Union and Australia. This was done to investigate the relevant lessons that can be learnt or adopted from these jurisdictions. The thesis further discusses the adequacy of the recently introduced provisions of the Financial Markets Bill as well as the subsequent market abuse provisions of the Financial Markets Bill 2012. The thesis highlights that the aforementioned Bills are positive attempts by the policy makers to improve the enforcement of the market abuse provisions in South Africa. Nonetheless, the thesis reveals that most of the shortcomings contained in the Securities Services Act 36 of 2004 were duplicated in the Financial Markets Bill and the Financial Markets Bill 2012. In light of this, it remains to be seen whether the market abuse provisions contained in the Financial Markets Bill and/or the Financial Markets Bill 2012 will improve the combating of market abuse practices in South Africa. Consequently, it is hoped that the relevant market abuse provisions of the Securities Services Act 36 of 2004, the Financial Markets Bill and/or the Financial Markets Bill 2012 will be comprehensively reviewed in regard to the recommendations made in this thesis. To this end, the thesis proposes a viable anti-market abuse model and policy framework and sets out both policy objectives and provisions which policy makers could use to strengthen some of the market abuse provisions in South Africa.
- Full Text:
- Date Issued: 2012
- Authors: Chitimira, Howard
- Date: 2012
- Subjects: Corporation law -- South Africa , Insider trading in securities -- South Africa , Securities -- South Africa , Efficient market theory , Securities fraud
- Language: English
- Type: Thesis , Doctoral , LLD
- Identifier: vital:10240 , http://hdl.handle.net/10948/d1015008
- Description: Market abuse practices may directly or indirectly give rise to diverse problems such as inaccurate stock market prices, low public investor confidence, reduced market integrity and poor efficiency in the affected financial markets. This thesis reveals that three major forms of market abuse, namely insider trading, prohibited trading practices (trade-based market manipulation) and the making or publication of false, misleading or deceptive statements, promises and forecasts relating to listed securities (disclosure-based market manipulation) are prohibited in South Africa. However, although South Africa has had market abuse legislation for about 30 years, and must be commended for its great effort to enhance market integrity by combating market abuse practices, the enforcement of such legislation is still problematic. Moreover, in spite of the fact that there is no empirical data or accurate figures quantifying the occurrence and extent of market abuse activities in the South African financial markets, this thesis submits that market abuse practices are still to be completely eradicated. Accordingly, this thesis suggests that the aforementioned problem might have been aggravated by inter alia, various gaps, flaws and/or inconsistent implementation and enforcement of the market abuse legislation in South Africa. To this end, the anti-market abuse enforcement framework under the Securities Services Act 36 of 2004 is analysed to investigate its adequacy. The co-operation and role of the Financial Services Board, the courts, the Directorate of Market Abuse and other relevant stakeholders is also examined and discussed. Moreover, the co-operation between the Financial Services Board and similar international agencies is discussed to gauge its effectiveness in relation to the combating of cross-border market abuse practices. The adequacy of the awareness and preventative measures in place to curb market abuse practices is also investigated to determine whether such measures are robust enough to combat other new challenges that were posed by the 2007 to 2009 global financial crisis. Furthermore, a comparative analysis is undertaken of the enforcement of the market abuse prohibition in other jurisdictions, namely the United States of America, the United Kingdom, the European Union and Australia. This was done to investigate the relevant lessons that can be learnt or adopted from these jurisdictions. The thesis further discusses the adequacy of the recently introduced provisions of the Financial Markets Bill as well as the subsequent market abuse provisions of the Financial Markets Bill 2012. The thesis highlights that the aforementioned Bills are positive attempts by the policy makers to improve the enforcement of the market abuse provisions in South Africa. Nonetheless, the thesis reveals that most of the shortcomings contained in the Securities Services Act 36 of 2004 were duplicated in the Financial Markets Bill and the Financial Markets Bill 2012. In light of this, it remains to be seen whether the market abuse provisions contained in the Financial Markets Bill and/or the Financial Markets Bill 2012 will improve the combating of market abuse practices in South Africa. Consequently, it is hoped that the relevant market abuse provisions of the Securities Services Act 36 of 2004, the Financial Markets Bill and/or the Financial Markets Bill 2012 will be comprehensively reviewed in regard to the recommendations made in this thesis. To this end, the thesis proposes a viable anti-market abuse model and policy framework and sets out both policy objectives and provisions which policy makers could use to strengthen some of the market abuse provisions in South Africa.
- Full Text:
- Date Issued: 2012
A comparative polarimetric study of the 43 GHz and 86 GHz SiO masers toward the supergiant star VY CMa
- Authors: Richter, Laura
- Date: 2012
- Subjects: Masers Supergiant stars Polarization (Light) Very long baseline interferometry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5454 , http://hdl.handle.net/10962/d1005239
- Description: The aim of this thesis is to perform observational tests of SiO maser polarisation and excitation models, using component-level comparisons of multiple SiO maser transitions in the 43 GHz and 86 GHz bands at milliarcsecond resolution. These observations reqwre very long baseline interferometric imaging with very accurate polarimetric calibration. The supergiant star VY CMa was chosen as the object of this study due to its high SiO maser luminosity, many detected SiO maser lines, and intrinsic scientific interest. Two epochs of full-polarisation VLBA observations of VY CMa were performed. The Epoch 2 observations were reduced using several new data reduction methods developed as part of this work, and designed specifically to improve the accuracy of circular polarisation calibration of spectral-line VLBI observations at millimetre wavelengths. The accuracy is estimated to be better than 1% using these methods. The Epoch 2 images show a concentration of v= l and v=2 J= 1-0 SiO masers to the east and northeast of the assumed stellar position. The v=l J=2-1 masers were more evenly distributed around the star, with a notable lack of emission in the northeast. There is appreciable spatial overlap between these three lines. The nature of the overlap is generally consistent with the predictions of hydrodynamical circumstellar SiO maser simulations. Where the v=l J = 1-0 and J =2-1 features overlap, the v=l J = 2-1 emission is usually considerably weaker. This is not predicted by current hydrodynamical models, but can be explained in the context of collisional pumping in a low density environment. Six observational tests of weak-splitting maser polarisation models were performed, including intercomparisons of linear polarisation in the v=l J=1-0 and J=2-1lines, linear polarisation versus saturation level, linear polarisation versus distance from the star, circular polarisation in the v= l J = 1-0 and J=2-1 lines, circular versus linear polarisation and modeling of ~ 900 electric-vector position angle rotations. The polarisation model tests generally do not support non-Zeeman circular polarisation mechanisms. For the linear polarisation tests, the results are more consistent with models that predict similar linear polarisation across transitions. The scientific importance of these tests is described in detail and avenues for future work are described.
- Full Text:
- Date Issued: 2012
- Authors: Richter, Laura
- Date: 2012
- Subjects: Masers Supergiant stars Polarization (Light) Very long baseline interferometry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5454 , http://hdl.handle.net/10962/d1005239
- Description: The aim of this thesis is to perform observational tests of SiO maser polarisation and excitation models, using component-level comparisons of multiple SiO maser transitions in the 43 GHz and 86 GHz bands at milliarcsecond resolution. These observations reqwre very long baseline interferometric imaging with very accurate polarimetric calibration. The supergiant star VY CMa was chosen as the object of this study due to its high SiO maser luminosity, many detected SiO maser lines, and intrinsic scientific interest. Two epochs of full-polarisation VLBA observations of VY CMa were performed. The Epoch 2 observations were reduced using several new data reduction methods developed as part of this work, and designed specifically to improve the accuracy of circular polarisation calibration of spectral-line VLBI observations at millimetre wavelengths. The accuracy is estimated to be better than 1% using these methods. The Epoch 2 images show a concentration of v= l and v=2 J= 1-0 SiO masers to the east and northeast of the assumed stellar position. The v=l J=2-1 masers were more evenly distributed around the star, with a notable lack of emission in the northeast. There is appreciable spatial overlap between these three lines. The nature of the overlap is generally consistent with the predictions of hydrodynamical circumstellar SiO maser simulations. Where the v=l J = 1-0 and J =2-1 features overlap, the v=l J = 2-1 emission is usually considerably weaker. This is not predicted by current hydrodynamical models, but can be explained in the context of collisional pumping in a low density environment. Six observational tests of weak-splitting maser polarisation models were performed, including intercomparisons of linear polarisation in the v=l J=1-0 and J=2-1lines, linear polarisation versus saturation level, linear polarisation versus distance from the star, circular polarisation in the v= l J = 1-0 and J=2-1 lines, circular versus linear polarisation and modeling of ~ 900 electric-vector position angle rotations. The polarisation model tests generally do not support non-Zeeman circular polarisation mechanisms. For the linear polarisation tests, the results are more consistent with models that predict similar linear polarisation across transitions. The scientific importance of these tests is described in detail and avenues for future work are described.
- Full Text:
- Date Issued: 2012
A comparative study of masculinity in the Twilight films and selected teen dramas
- Theodosiou, Stephanie Nicole
- Authors: Theodosiou, Stephanie Nicole
- Date: 2012
- Subjects: Masculinity in motion pictures
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:8425 , http://hdl.handle.net/10948/d1019976
- Description: This research paper aims to investigate the effect mainstream cinema has on the formulation and practice of the masculine stereotype in society, thus exploring the representations of masculinity being provided to males through mainstream cinema. This paper examines the representation of masculinity with reference to cinematic depictions of male masculinity produced in the film category of Teen Drama in the 90‘s/ 2000‘s and 2010 to determine the image the media enforces, through cinema, to influence what males modeled themselves on in both the past and present. This treatise shows the effect the media had on men in the past and how present day men continue to base their individual identity, which has been dramatically influenced and stereotyped by the high standards of the media, by analyzing the movie phenomenon of the Twilight franchise (1 to 3) with reference to Clueless (Amy Heckerling, 1995), 10 Things I hate About You (Gil Junger, 1999), Bring It On (Peyton Reed, 2000), John Tucker Must Die (Betty Thomas, 2006), Easy A (Will Gluck, 2010) and I am Number Four (D.J. Caruso, 2011) featured in the 90‘s/ 2000‘s and 2010. This was carried out through qualitative semiotic research to determine the overall influence the media, particularly mainstream cinema, has on the ideals of masculinity that heterosexual males seek to attain.
- Full Text:
- Date Issued: 2012
- Authors: Theodosiou, Stephanie Nicole
- Date: 2012
- Subjects: Masculinity in motion pictures
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:8425 , http://hdl.handle.net/10948/d1019976
- Description: This research paper aims to investigate the effect mainstream cinema has on the formulation and practice of the masculine stereotype in society, thus exploring the representations of masculinity being provided to males through mainstream cinema. This paper examines the representation of masculinity with reference to cinematic depictions of male masculinity produced in the film category of Teen Drama in the 90‘s/ 2000‘s and 2010 to determine the image the media enforces, through cinema, to influence what males modeled themselves on in both the past and present. This treatise shows the effect the media had on men in the past and how present day men continue to base their individual identity, which has been dramatically influenced and stereotyped by the high standards of the media, by analyzing the movie phenomenon of the Twilight franchise (1 to 3) with reference to Clueless (Amy Heckerling, 1995), 10 Things I hate About You (Gil Junger, 1999), Bring It On (Peyton Reed, 2000), John Tucker Must Die (Betty Thomas, 2006), Easy A (Will Gluck, 2010) and I am Number Four (D.J. Caruso, 2011) featured in the 90‘s/ 2000‘s and 2010. This was carried out through qualitative semiotic research to determine the overall influence the media, particularly mainstream cinema, has on the ideals of masculinity that heterosexual males seek to attain.
- Full Text:
- Date Issued: 2012
A comparative study of the language, mathematics and science literacy knowledge and skills of grade 9 learners in secondary schools in Port Elizabeth
- Authors: Arnolds, Keith Victor
- Date: 2012
- Subjects: Educational tests and measurements -- South Africa -- Port Elizabeth , Comparative education , Language and languages -- Study and teaching -- South Africa -- Port Elizabeth , Mathematics -- Study and teaching -- South Africa -- Port Elizabeth , Science -- Study and teaching -- South Africa -- Port Elizabeth , Education, Secondary -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9566 , http://hdl.handle.net/10948/d1016062
- Description: In South Africa, on-going concerns surrounding the development of learners’ literacy, mathematics and science skills are evident and drive various research studies in this field. International studies and assessments, such as the Trends in International Mathematics and Science Study (TIMSS) and the Progress in International Reading Literacy Study (PIRLS) show major differences in the proficiency levels of learners in South Africa in comparison with their international counter parts. To date, however, the more comprehensive international standardised assessment called the Programme for International Student Assessment (PISA), has not been administered in South Africa. The main aim of this research study was to investigate and scientifically explore the real situation in terms of language, mathematics and science literacy knowledge and skills of Grade 9 learners in South Africa and to draw a comparison between Grade 9 learners from secondary schools in the Port Elizabeth district in South Africa and their international counterparts, using the PISA standardised international assessment. In addition, the aim of the study was to determine the actual language, mathematics and science literacy skills and knowledge acquired by participants in this study. Quantitative data collection was done by administering a modified version of the Program for International Student Assessment (PISA) to learners from eight schools in Port Elizabeth, supplemented with questionnaires completed by participating learners and school principals. Findings revealed that the South African learners sampled, ranked in the bottom percentile of participating countries in reading, mathematics and science. The study also exposed the glaring inequalities still prevalent in South African education today, 17 years into democracy. The implications point to a serious investigation into the societal and political factors responsible for the discrepancies in the South African educational system at present.
- Full Text:
- Date Issued: 2012
- Authors: Arnolds, Keith Victor
- Date: 2012
- Subjects: Educational tests and measurements -- South Africa -- Port Elizabeth , Comparative education , Language and languages -- Study and teaching -- South Africa -- Port Elizabeth , Mathematics -- Study and teaching -- South Africa -- Port Elizabeth , Science -- Study and teaching -- South Africa -- Port Elizabeth , Education, Secondary -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9566 , http://hdl.handle.net/10948/d1016062
- Description: In South Africa, on-going concerns surrounding the development of learners’ literacy, mathematics and science skills are evident and drive various research studies in this field. International studies and assessments, such as the Trends in International Mathematics and Science Study (TIMSS) and the Progress in International Reading Literacy Study (PIRLS) show major differences in the proficiency levels of learners in South Africa in comparison with their international counter parts. To date, however, the more comprehensive international standardised assessment called the Programme for International Student Assessment (PISA), has not been administered in South Africa. The main aim of this research study was to investigate and scientifically explore the real situation in terms of language, mathematics and science literacy knowledge and skills of Grade 9 learners in South Africa and to draw a comparison between Grade 9 learners from secondary schools in the Port Elizabeth district in South Africa and their international counterparts, using the PISA standardised international assessment. In addition, the aim of the study was to determine the actual language, mathematics and science literacy skills and knowledge acquired by participants in this study. Quantitative data collection was done by administering a modified version of the Program for International Student Assessment (PISA) to learners from eight schools in Port Elizabeth, supplemented with questionnaires completed by participating learners and school principals. Findings revealed that the South African learners sampled, ranked in the bottom percentile of participating countries in reading, mathematics and science. The study also exposed the glaring inequalities still prevalent in South African education today, 17 years into democracy. The implications point to a serious investigation into the societal and political factors responsible for the discrepancies in the South African educational system at present.
- Full Text:
- Date Issued: 2012
A comparative study on the sensitive detection of hydroxyl radical using thiol-capped CdTe and CdTe/ZnS quantum dots
- Adegoke, Oluwasesan, Nyokong, Tebello
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242778 , vital:51077 , xlink:href="https://doi.org/10.1007/s10895-012-1089-2"
- Description: Four types of water-soluble luminescent quantum dots (QDs) whose surface was functionlaized with thioglycolic acid (TGA), 3-mercaptopropionic acid (MPA), or glutathione (GSH), were investigated for the sensitive and selective detection of hydroxyl radical (●OH) in aqueous media. It was found that the type of capping agent and QD influenced the sensitivity of the probe. The order of sensitivity of the probe was: GSH-CdTe@ZnS > MPA-CdTe@ZnS > TGA-CdTe > MPA-CdTe QDs. Under the optimum conditions, a limit of detection as low as 8.5 × 10-8 M was obtained using GSH-CdTe@ZnS. The effects of foreign reactive oxygen species and the Fenton reactants and products as possible interferences on the proposed probe were negligible for CdTe@ZnS QDs. Besides, experimental results indicated that CdTe@ZnS QDs were more attractive for the selective recognition of ●OH than CdTe QDs. The mechanistic reaction pathway between the QDs and ●OH is proposed.
- Full Text:
- Date Issued: 2012
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242778 , vital:51077 , xlink:href="https://doi.org/10.1007/s10895-012-1089-2"
- Description: Four types of water-soluble luminescent quantum dots (QDs) whose surface was functionlaized with thioglycolic acid (TGA), 3-mercaptopropionic acid (MPA), or glutathione (GSH), were investigated for the sensitive and selective detection of hydroxyl radical (●OH) in aqueous media. It was found that the type of capping agent and QD influenced the sensitivity of the probe. The order of sensitivity of the probe was: GSH-CdTe@ZnS > MPA-CdTe@ZnS > TGA-CdTe > MPA-CdTe QDs. Under the optimum conditions, a limit of detection as low as 8.5 × 10-8 M was obtained using GSH-CdTe@ZnS. The effects of foreign reactive oxygen species and the Fenton reactants and products as possible interferences on the proposed probe were negligible for CdTe@ZnS QDs. Besides, experimental results indicated that CdTe@ZnS QDs were more attractive for the selective recognition of ●OH than CdTe QDs. The mechanistic reaction pathway between the QDs and ●OH is proposed.
- Full Text:
- Date Issued: 2012
A comparison between the approaches to unfair discrimination in employment in South Africa and Nigeria
- Authors: Odeyemi, Hannah Olubunmi
- Date: 2012
- Subjects: Discrimination in employment -- Law and legislation -- South Africa , Discrimination in employment -- Law and legislation -- Nigeria , Unfair labor practices -- South Africa , Unfair labor practices -- Nigeria
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:10270 , http://hdl.handle.net/10948/d1012054 , Discrimination in employment -- Law and legislation -- South Africa , Discrimination in employment -- Law and legislation -- Nigeria , Unfair labor practices -- South Africa , Unfair labor practices -- Nigeria
- Description: Issues concerning employment are some of the most serious issues of our time. But it is in the last two decades or so that these started receiving consideration. For instance, South Africa has experienced changes in the landscape of employment relations in organisations in the last decades. And no area of South Africa law is more critical than the prohibition of unfair discrimination, especially in the workpalce. The enactment of the Constitution brought about the need to eradicate unfair discrimination in the workpalce. Section 9 of the Constitution states that no person may unfairly discriminate directly or indirectly against anyone and that national legislation must be enacted to prevent or prohibit unfair discrimination. To enforce this, certain legislations like the Labour Law Act, Employment Act, Promotion of Equality and Prohibition of Unfair Discrimination Act (Equality Act), were enacted to give effect to the equality provision of the Constitution. In a similar vein, in Nigeria, workplace discrimination which is at the top of human rights violation perpetrated by employers of labour is of paramount concern to legislators and the government. Sex , age, ethinicty, religion, trade union membership and political opinion are some of the grounds upon which workers may not be discriminated against in Nigeria. Section 17 of the Constitution states that the State social order is founded on the ideals of freedom, equality and justice. It goes on to provide that every citizen shall have equality of rights, obligations and opportunities before the law. More specifically, the section stipilates that the State shall ensure that all citizens, without discrimination of any group whatsoever, have the opportunity of livehood as well as adequate opportunity to secure suitable employment and that there is equal pay for equal work without discrimination on account of sex, or any ground. Hence, there are The Nigerian Labour Act, the Federal Character Commission, etc that are saddled with the responsibility of addressing unfair discrimination and giving force to the provision of the Constitution. Despite the anti-discrimination laws and provisions made available in both countries, it is still alarming to see that unfair discrimination in the workplace is still on the increase. This, as will be discussed later, is probably due to factors such as lack of communication, long-stading patterns of educational inequalities that have resulted in inequalities in manpower, differences in drive, motivation, cultural disposition and geographical opportunities, racial difference and ethnicity, domination of one group by the other, etc. This research will briefly focus on the comparison between the approaches to unfair discrimination in employment between South Africa and Nigeria. It will discuss the development of unfair discrimination, grounds on which it is perpetrated, defences relating to unfair discrimination, and anti-discrimination laws put in place by the two jurisdictions to curb discrimination, as well as suggest on how to forestall unfair discrimination.
- Full Text:
- Date Issued: 2012
- Authors: Odeyemi, Hannah Olubunmi
- Date: 2012
- Subjects: Discrimination in employment -- Law and legislation -- South Africa , Discrimination in employment -- Law and legislation -- Nigeria , Unfair labor practices -- South Africa , Unfair labor practices -- Nigeria
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:10270 , http://hdl.handle.net/10948/d1012054 , Discrimination in employment -- Law and legislation -- South Africa , Discrimination in employment -- Law and legislation -- Nigeria , Unfair labor practices -- South Africa , Unfair labor practices -- Nigeria
- Description: Issues concerning employment are some of the most serious issues of our time. But it is in the last two decades or so that these started receiving consideration. For instance, South Africa has experienced changes in the landscape of employment relations in organisations in the last decades. And no area of South Africa law is more critical than the prohibition of unfair discrimination, especially in the workpalce. The enactment of the Constitution brought about the need to eradicate unfair discrimination in the workpalce. Section 9 of the Constitution states that no person may unfairly discriminate directly or indirectly against anyone and that national legislation must be enacted to prevent or prohibit unfair discrimination. To enforce this, certain legislations like the Labour Law Act, Employment Act, Promotion of Equality and Prohibition of Unfair Discrimination Act (Equality Act), were enacted to give effect to the equality provision of the Constitution. In a similar vein, in Nigeria, workplace discrimination which is at the top of human rights violation perpetrated by employers of labour is of paramount concern to legislators and the government. Sex , age, ethinicty, religion, trade union membership and political opinion are some of the grounds upon which workers may not be discriminated against in Nigeria. Section 17 of the Constitution states that the State social order is founded on the ideals of freedom, equality and justice. It goes on to provide that every citizen shall have equality of rights, obligations and opportunities before the law. More specifically, the section stipilates that the State shall ensure that all citizens, without discrimination of any group whatsoever, have the opportunity of livehood as well as adequate opportunity to secure suitable employment and that there is equal pay for equal work without discrimination on account of sex, or any ground. Hence, there are The Nigerian Labour Act, the Federal Character Commission, etc that are saddled with the responsibility of addressing unfair discrimination and giving force to the provision of the Constitution. Despite the anti-discrimination laws and provisions made available in both countries, it is still alarming to see that unfair discrimination in the workplace is still on the increase. This, as will be discussed later, is probably due to factors such as lack of communication, long-stading patterns of educational inequalities that have resulted in inequalities in manpower, differences in drive, motivation, cultural disposition and geographical opportunities, racial difference and ethnicity, domination of one group by the other, etc. This research will briefly focus on the comparison between the approaches to unfair discrimination in employment between South Africa and Nigeria. It will discuss the development of unfair discrimination, grounds on which it is perpetrated, defences relating to unfair discrimination, and anti-discrimination laws put in place by the two jurisdictions to curb discrimination, as well as suggest on how to forestall unfair discrimination.
- Full Text:
- Date Issued: 2012
A comparison of harvester productivity and stump volume waste in coppiced and planted eucalyptus grandis pulpwood compartments in the KwaZulu-Natal forestry region of South Africa
- Ramantswana, Mufhumudzi Muedanyi
- Authors: Ramantswana, Mufhumudzi Muedanyi
- Date: 2012
- Subjects: Forest productivity , Forest management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10744 , http://hdl.handle.net/10948/d1019844
- Description: Over the past decade the South African forestry industry has gradually experienced the ramifications of labour scarcity, increases in labour costs, the effect of HIV and AIDS and increasing timber demand. Consequently, this has led to an increase in the mechanisation rate, especially in timber harvesting operations. Due to the labour challenges in South Africa, mechanised forestry equipment has increasingly been required to operate in complex forest conditions, such as coppiced compartments, where they have not operated before. It therefore occurs that harvesters are either used in certain coppiced compartments with uncertain productivity expectations, or the harvesters are not used in these compartments due to a lack of productivity knowledge. The influence that certain factors have on harvester productivity and stump volume loss – factors such as coppice regeneration practices and stem form – is poorly understood and has not been quantified. No scientific research exists regarding the effects of coppice compartments on the productivity of a harvester and the amount of stump volume waste. This research aimed at determining the influence of tree volume, tree form, stem felled first and distance between stems on the productivity of an excavator based harvester in coppiced double, coppiced single and planted Eucalyptus grandis pulpwood compartments. Furthermore, the research determined whether there was any stump volume waste, and quantified how much of it was due to excessive stump heights by the harvester. Through regression analysis, productivity equations were derived to make productivity predictions in both coppiced and planted compartments. All stumps were evaluated for waste and the average stump volume waste in coppiced double, coppiced single and planted trees was determined. The research results showed that planted trees had the highest productivity across all tree sizes, followed by coppiced single trees and then coppiced double stems. When harvesting a 0.2 m3 tree, the mean harvester productivity was 8.7 m3 per PMH in coppiced double trees, 13.8 m3 per PMH in coppiced single trees and 16.1 m3 per PMH in planted trees. In coppiced double stems the productivity was not significantly influence by the distance between stems. However, the productivity was significantly influenced by the stem felled first. The regression results showed that if the smaller stem was felled first, the productivity would increase if the larger stem’s volume was less than 0.18 m3; however where the larger stem was greater than 0.18 m3, the relationship was reversed. In addition, the productivity for both coppiced single trees and coppiced double stems were significantly influenced by stem form. The poorly formed trees had low productivity compared to the trees with good form. The stump volume findings showed that coppiced double stems had the highest average stump volume waste per stump, with 0.00307 m3 waste, followed by coppiced single trees (0.001954 m3) and planted trees (0.001650 m3). The average stump volume waste per stump with waste for the planted trees was negligible. This research provides forestry companies and harvesting contractors with information on the effect of tree volume, tree form and stem felled first on harvester productivity in E. grandis coppiced double, coppiced single and planted compartments. This information will assist in making equipment and system selection decisions and improve operational management and control. In addition, they will also be aware of stump volume losses that will occur in the three scenarios.
- Full Text:
- Date Issued: 2012
- Authors: Ramantswana, Mufhumudzi Muedanyi
- Date: 2012
- Subjects: Forest productivity , Forest management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10744 , http://hdl.handle.net/10948/d1019844
- Description: Over the past decade the South African forestry industry has gradually experienced the ramifications of labour scarcity, increases in labour costs, the effect of HIV and AIDS and increasing timber demand. Consequently, this has led to an increase in the mechanisation rate, especially in timber harvesting operations. Due to the labour challenges in South Africa, mechanised forestry equipment has increasingly been required to operate in complex forest conditions, such as coppiced compartments, where they have not operated before. It therefore occurs that harvesters are either used in certain coppiced compartments with uncertain productivity expectations, or the harvesters are not used in these compartments due to a lack of productivity knowledge. The influence that certain factors have on harvester productivity and stump volume loss – factors such as coppice regeneration practices and stem form – is poorly understood and has not been quantified. No scientific research exists regarding the effects of coppice compartments on the productivity of a harvester and the amount of stump volume waste. This research aimed at determining the influence of tree volume, tree form, stem felled first and distance between stems on the productivity of an excavator based harvester in coppiced double, coppiced single and planted Eucalyptus grandis pulpwood compartments. Furthermore, the research determined whether there was any stump volume waste, and quantified how much of it was due to excessive stump heights by the harvester. Through regression analysis, productivity equations were derived to make productivity predictions in both coppiced and planted compartments. All stumps were evaluated for waste and the average stump volume waste in coppiced double, coppiced single and planted trees was determined. The research results showed that planted trees had the highest productivity across all tree sizes, followed by coppiced single trees and then coppiced double stems. When harvesting a 0.2 m3 tree, the mean harvester productivity was 8.7 m3 per PMH in coppiced double trees, 13.8 m3 per PMH in coppiced single trees and 16.1 m3 per PMH in planted trees. In coppiced double stems the productivity was not significantly influence by the distance between stems. However, the productivity was significantly influenced by the stem felled first. The regression results showed that if the smaller stem was felled first, the productivity would increase if the larger stem’s volume was less than 0.18 m3; however where the larger stem was greater than 0.18 m3, the relationship was reversed. In addition, the productivity for both coppiced single trees and coppiced double stems were significantly influenced by stem form. The poorly formed trees had low productivity compared to the trees with good form. The stump volume findings showed that coppiced double stems had the highest average stump volume waste per stump, with 0.00307 m3 waste, followed by coppiced single trees (0.001954 m3) and planted trees (0.001650 m3). The average stump volume waste per stump with waste for the planted trees was negligible. This research provides forestry companies and harvesting contractors with information on the effect of tree volume, tree form and stem felled first on harvester productivity in E. grandis coppiced double, coppiced single and planted compartments. This information will assist in making equipment and system selection decisions and improve operational management and control. In addition, they will also be aware of stump volume losses that will occur in the three scenarios.
- Full Text:
- Date Issued: 2012
A computer network attack taxonomy and ontology
- Van Heerden, Renier P, Irwin, Barry V W, Burke, Ivan D, Leenen, Louise
- Authors: Van Heerden, Renier P , Irwin, Barry V W , Burke, Ivan D , Leenen, Louise
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430064 , vital:72663 , DOI: 10.4018/ijcwt.2012070102
- Description: Computer network attacks differ in the motivation of the entity behind the attack, the execution and the end result. The diversity of attacks has the consequence that no standard classification ex-ists. The benefit of automated classification of attacks, means that an attack could be mitigated accordingly. The authors extend a previous, initial taxonomy of computer network attacks which forms the basis of a proposed network attack ontology in this pa-per. The objective of this ontology is to automate the classifica-tion of a network attack during its early stages. Most published taxonomies present an attack from either the attacker's or defend-er's point of view. The authors' taxonomy presents both these points of view. The framework for an ontology was developed using a core class, the "Attack Scenario", which can be used to characterize and classify computer network attacks.
- Full Text:
- Date Issued: 2012
- Authors: Van Heerden, Renier P , Irwin, Barry V W , Burke, Ivan D , Leenen, Louise
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430064 , vital:72663 , DOI: 10.4018/ijcwt.2012070102
- Description: Computer network attacks differ in the motivation of the entity behind the attack, the execution and the end result. The diversity of attacks has the consequence that no standard classification ex-ists. The benefit of automated classification of attacks, means that an attack could be mitigated accordingly. The authors extend a previous, initial taxonomy of computer network attacks which forms the basis of a proposed network attack ontology in this pa-per. The objective of this ontology is to automate the classifica-tion of a network attack during its early stages. Most published taxonomies present an attack from either the attacker's or defend-er's point of view. The authors' taxonomy presents both these points of view. The framework for an ontology was developed using a core class, the "Attack Scenario", which can be used to characterize and classify computer network attacks.
- Full Text:
- Date Issued: 2012