Duplicating road patterns in south african informal settlements using procedural techniques
- Glass, Kevin R, Morkel, Chantelle, Bangay, Shaun D
- Authors: Glass, Kevin R , Morkel, Chantelle , Bangay, Shaun D
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432875 , vital:72909 , https://doi.org/10.1145/1108590.1108616
- Description: The formation of informal settlements in and around urban complexes has largely been ignored in the context of procedural city modeling. However, many cities in South Africa and globally can attest to the presence of such settlements. This paper analyses the phenomenon of informal settlements from a procedural modeling perspective. Aerial photography from two South African urban complexes, namely Johannesburg and Cape Town is used as a basis for the extraction of various features that distinguish different types of settlements. In particular, the road patterns which have formed within such settlements are analysed, and various procedural techniques proposed (including Voronoi diagrams, subdivision and L-systems) to replicate the identified features. A qualitative assessment of the procedural techniques is provided, and the most suitable combination of techniques identified for unstructured and structured settlements. In particular it is found that a combination of Voronoi diagrams and subdivision provides the closest match to unstructured informal settlements. A combination of L-systems, Voronoi diagrams and subdivision is found to produce the closest pattern to a structured informal settlement.
- Full Text:
- Date Issued: 2006
- Authors: Glass, Kevin R , Morkel, Chantelle , Bangay, Shaun D
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432875 , vital:72909 , https://doi.org/10.1145/1108590.1108616
- Description: The formation of informal settlements in and around urban complexes has largely been ignored in the context of procedural city modeling. However, many cities in South Africa and globally can attest to the presence of such settlements. This paper analyses the phenomenon of informal settlements from a procedural modeling perspective. Aerial photography from two South African urban complexes, namely Johannesburg and Cape Town is used as a basis for the extraction of various features that distinguish different types of settlements. In particular, the road patterns which have formed within such settlements are analysed, and various procedural techniques proposed (including Voronoi diagrams, subdivision and L-systems) to replicate the identified features. A qualitative assessment of the procedural techniques is provided, and the most suitable combination of techniques identified for unstructured and structured settlements. In particular it is found that a combination of Voronoi diagrams and subdivision provides the closest match to unstructured informal settlements. A combination of L-systems, Voronoi diagrams and subdivision is found to produce the closest pattern to a structured informal settlement.
- Full Text:
- Date Issued: 2006
Evaluation of kinetic parameters of traps in thermoluminescence phosphors
- Ogundare, F O, Balogun, F A, Hussain, L
- Authors: Ogundare, F O , Balogun, F A , Hussain, L
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6798 , http://hdl.handle.net/10962/d1003924 , http://dx.doi.org/10.1016/j.radmeas.2006.06.014
- Description: A method for evaluating trap depth E, order of kinetics b and frequency factor s from a thermoluminescence (TL) glow peak has been developed. The method is based on using intensities and temperatures at any three points on the glow peak. Unlike similar techniques that provide no expression for frequency factor, the present formulation provides such an expression. The expression does not require knowledge of the temperature at which maximum intensity occurs, a parameter not usually known accurately from experimental glow peak data. For the method, it is found that use of points in the ascending part of the glow peak where the intensities are less than 10% maximum intensity gives parameter values closest to the true ones. Possible reasons for getting less accurate results when points are taken beyond this region are discussed. Values of the activation energy calculated using the present technique were always close to the true value. However, the frequency factor only approaches the true value as the dose given to the sample approaches saturation. When the three data points are selected in the initial-rise region, the equation for evaluating E in the method described in this paper becomes a two-point version of the initial-rise method. The advantage of the present technique over the initial-rise method is that it also gives b and hence s. The method is used to analyse the TL glow curve of a gamma-irradiated sample from Ijero-Ekiti, Nigeria.
- Full Text:
- Date Issued: 2006
- Authors: Ogundare, F O , Balogun, F A , Hussain, L
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6798 , http://hdl.handle.net/10962/d1003924 , http://dx.doi.org/10.1016/j.radmeas.2006.06.014
- Description: A method for evaluating trap depth E, order of kinetics b and frequency factor s from a thermoluminescence (TL) glow peak has been developed. The method is based on using intensities and temperatures at any three points on the glow peak. Unlike similar techniques that provide no expression for frequency factor, the present formulation provides such an expression. The expression does not require knowledge of the temperature at which maximum intensity occurs, a parameter not usually known accurately from experimental glow peak data. For the method, it is found that use of points in the ascending part of the glow peak where the intensities are less than 10% maximum intensity gives parameter values closest to the true ones. Possible reasons for getting less accurate results when points are taken beyond this region are discussed. Values of the activation energy calculated using the present technique were always close to the true value. However, the frequency factor only approaches the true value as the dose given to the sample approaches saturation. When the three data points are selected in the initial-rise region, the equation for evaluating E in the method described in this paper becomes a two-point version of the initial-rise method. The advantage of the present technique over the initial-rise method is that it also gives b and hence s. The method is used to analyse the TL glow curve of a gamma-irradiated sample from Ijero-Ekiti, Nigeria.
- Full Text:
- Date Issued: 2006
Grahamstown film and heritage as reflected by His Majesty's building
- Authors: Still-Drewett, F
- Date: 2006
- Language: English
- Type: Text
- Identifier: vital:6981 , http://hdl.handle.net/10962/d1012409
- Description: Grahamstown Film and Heritage as reflected by His Majesty's Building. The building of His Majesty's theatre has had and continues to have an influential and varied history in the town of Grahamstown. The heritage of the building is linked both to its historical purpose and role in the community, and with the imposing architectural features and central locality. In this oral history project HMT became a vehicle for researching broader issues. The following issues arose: the effects of apartheid policy in entertainment areas; the arrival of national franchises and resultant tensions of preservation of building and cultural heritage versus economic development; the impact of new media such as TV and Video on the cinema theatre; and the community Fruit & Veg 'Colour' dispute. Four key informants were selected and 5 oral history interviews conducted in May 2006. The history of the theatre, film and entertainment memoirs, social comment, and a life history were recorded. , The oral history project pertaining to this paper is housed at the Cory Library, Rhodes University. See also Oral History Association of South Africa: http://www.ohasa.org.za/
- Full Text:
- Date Issued: 2006
- Authors: Still-Drewett, F
- Date: 2006
- Language: English
- Type: Text
- Identifier: vital:6981 , http://hdl.handle.net/10962/d1012409
- Description: Grahamstown Film and Heritage as reflected by His Majesty's Building. The building of His Majesty's theatre has had and continues to have an influential and varied history in the town of Grahamstown. The heritage of the building is linked both to its historical purpose and role in the community, and with the imposing architectural features and central locality. In this oral history project HMT became a vehicle for researching broader issues. The following issues arose: the effects of apartheid policy in entertainment areas; the arrival of national franchises and resultant tensions of preservation of building and cultural heritage versus economic development; the impact of new media such as TV and Video on the cinema theatre; and the community Fruit & Veg 'Colour' dispute. Four key informants were selected and 5 oral history interviews conducted in May 2006. The history of the theatre, film and entertainment memoirs, social comment, and a life history were recorded. , The oral history project pertaining to this paper is housed at the Cory Library, Rhodes University. See also Oral History Association of South Africa: http://www.ohasa.org.za/
- Full Text:
- Date Issued: 2006
Managing South Africa's trawl bycatch
- Walmsley, Sarah A, Leslie, Rob W, Sauer, Warwick H H
- Authors: Walmsley, Sarah A , Leslie, Rob W , Sauer, Warwick H H
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124954 , vital:35713 , https://doi.10.1093/icesjms/fsl022
- Description: Over the past few decades, it has become widely recognized that the management strategies of world fisheries must ensure sustainability of bycatch as well as of target species. South Africa implemented a pilot observer programme from 1995 to 2000 to collect data on the levels and patterns of bycatch and discards in the demersal trawl fishery. Here, the results of that programme are used in conjunction with information on bycatch value and compliance to assess the issues and problems regarding bycatch and discarding in the fishery. In general, bycatch components can be placed into one of three categories (discarded bycatch, retained bycatch, and processing waste), each of which present different management problems and require different management approaches. The results were used to formulate a bycatch management plan for the demersal trawl fishery in South Africa. Given the need to continue monitoring bycatch, the performance of the pilot observer programme is reviewed, and the levels of sampling effort required for a national programme are discussed.
- Full Text:
- Date Issued: 2006
- Authors: Walmsley, Sarah A , Leslie, Rob W , Sauer, Warwick H H
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124954 , vital:35713 , https://doi.10.1093/icesjms/fsl022
- Description: Over the past few decades, it has become widely recognized that the management strategies of world fisheries must ensure sustainability of bycatch as well as of target species. South Africa implemented a pilot observer programme from 1995 to 2000 to collect data on the levels and patterns of bycatch and discards in the demersal trawl fishery. Here, the results of that programme are used in conjunction with information on bycatch value and compliance to assess the issues and problems regarding bycatch and discarding in the fishery. In general, bycatch components can be placed into one of three categories (discarded bycatch, retained bycatch, and processing waste), each of which present different management problems and require different management approaches. The results were used to formulate a bycatch management plan for the demersal trawl fishery in South Africa. Given the need to continue monitoring bycatch, the performance of the pilot observer programme is reviewed, and the levels of sampling effort required for a national programme are discussed.
- Full Text:
- Date Issued: 2006
Review of the African distribution of the brine shrimp genus Artemia
- Kaiser, Horst, Gordon, Andrew K, Paulet, T G
- Authors: Kaiser, Horst , Gordon, Andrew K , Paulet, T G
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6765 , http://hdl.handle.net/10962/d1007963
- Description: Brine shrimp (genus Artemia) are small (8 to 12 mm long) cosmopolitan crustaceans (Anostraca) found predominately in hypersaline water bodies such as inland salt lakes and pans, coastal lagoons, and salt works at salinity levels above 40 g(.)l[superscript(-1)]. They have been extensively studied due to their high monetary value as food for larval fish in aquaculture and their unique reproductive strategies. Brine shrimp occur as either bisexual species or as parthenogenetic populations. Despite published reviews of their world-wide distribution little is known about their occurrence in Africa. This review adds new information about 70 African Artemia sites and lists 26 potential sites and their coordinates. Sixteen sites in Southern Africa and Namibia were visited during a collecting trip, and new information on the reproductive mode of nine of these sites is given. Several South African populations exhibit bisexual reproduction. In Namibia there are two parthenogenetic populations (Walvis Bay and Swartkops) and an additional bisexual population (Hentie's Bay). A mixed population (bisexual and parthenogenetic reproduction at the same site) was found at Coega, South Africa.
- Full Text:
- Date Issued: 2006
- Authors: Kaiser, Horst , Gordon, Andrew K , Paulet, T G
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6765 , http://hdl.handle.net/10962/d1007963
- Description: Brine shrimp (genus Artemia) are small (8 to 12 mm long) cosmopolitan crustaceans (Anostraca) found predominately in hypersaline water bodies such as inland salt lakes and pans, coastal lagoons, and salt works at salinity levels above 40 g(.)l[superscript(-1)]. They have been extensively studied due to their high monetary value as food for larval fish in aquaculture and their unique reproductive strategies. Brine shrimp occur as either bisexual species or as parthenogenetic populations. Despite published reviews of their world-wide distribution little is known about their occurrence in Africa. This review adds new information about 70 African Artemia sites and lists 26 potential sites and their coordinates. Sixteen sites in Southern Africa and Namibia were visited during a collecting trip, and new information on the reproductive mode of nine of these sites is given. Several South African populations exhibit bisexual reproduction. In Namibia there are two parthenogenetic populations (Walvis Bay and Swartkops) and an additional bisexual population (Hentie's Bay). A mixed population (bisexual and parthenogenetic reproduction at the same site) was found at Coega, South Africa.
- Full Text:
- Date Issued: 2006
Sidelining developmental goals? Re-imaging Port Elizabeth for the 2010 Soccer World Cup
- Authors: Baines, Gary F
- Date: 2006
- Language: English
- Type: Conference paper
- Identifier: vital:6155 , http://hdl.handle.net/10962/d1007070
- Full Text:
- Date Issued: 2006
- Authors: Baines, Gary F
- Date: 2006
- Language: English
- Type: Conference paper
- Identifier: vital:6155 , http://hdl.handle.net/10962/d1007070
- Full Text:
- Date Issued: 2006
Wireless Security Tools
- Janse van Rensburg, Johanna, Irwin, Barry V W
- Authors: Janse van Rensburg, Johanna , Irwin, Barry V W
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429867 , vital:72647 , https://digifors.cs.up.ac.za/issa/2006/Proceedings/Research/113_Paper.pdf
- Description: Detecting and investigating intrusive Internet activity is an ever-present challenge for network administrators and security researchers. Network monitoring can generate large, unmanageable amounts of log data, which further complicates distinguishing between illegitimate and legiti-mate traffic. Considering the above issue, this article has two aims. First, it describes an investigative methodology for network monitoring and traffic review; and second, it discusses results from applying this method. The method entails a combination of network telescope traffic capture and visualisation. Observing traffic from the perspective of a dedicated sensor network reduces the volume of data and alleviates the concern of confusing malicious traffic with legitimate traffic. Com-plimenting this, visual analysis facilitates the rapid review and correla-tion of events, thereby utilizing human intelligence in the identification of scanning patterns. To demonstrate the proposed method, several months of network telescope traffic is captured and analysed with a tai-lor made 3D scatter-plot visualisation. As the results show, the visuali-sation saliently conveys anomalous patterns, and further analysis re-veals that these patterns are indicative of covert network probing activi-ty. By incorporating visual analysis with traditional approaches, such as textual log review and the use of an intrusion detection system, this re-search contributes improved insight into network scanning incidents.
- Full Text:
- Date Issued: 2006
- Authors: Janse van Rensburg, Johanna , Irwin, Barry V W
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429867 , vital:72647 , https://digifors.cs.up.ac.za/issa/2006/Proceedings/Research/113_Paper.pdf
- Description: Detecting and investigating intrusive Internet activity is an ever-present challenge for network administrators and security researchers. Network monitoring can generate large, unmanageable amounts of log data, which further complicates distinguishing between illegitimate and legiti-mate traffic. Considering the above issue, this article has two aims. First, it describes an investigative methodology for network monitoring and traffic review; and second, it discusses results from applying this method. The method entails a combination of network telescope traffic capture and visualisation. Observing traffic from the perspective of a dedicated sensor network reduces the volume of data and alleviates the concern of confusing malicious traffic with legitimate traffic. Com-plimenting this, visual analysis facilitates the rapid review and correla-tion of events, thereby utilizing human intelligence in the identification of scanning patterns. To demonstrate the proposed method, several months of network telescope traffic is captured and analysed with a tai-lor made 3D scatter-plot visualisation. As the results show, the visuali-sation saliently conveys anomalous patterns, and further analysis re-veals that these patterns are indicative of covert network probing activi-ty. By incorporating visual analysis with traditional approaches, such as textual log review and the use of an intrusion detection system, this re-search contributes improved insight into network scanning incidents.
- Full Text:
- Date Issued: 2006
Critical perspectives on research on post-traumatic stress disorder and implications for the South African context
- Authors: Edwards, David J A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6228 , http://hdl.handle.net/10962/d1007778
- Description: This article introduces a special issue of the Journal of Psychology in Africa on post-traumatic stress disorder (PTSD) in Africa and particularly in South Africa and examines the critical debate that has surrounded PTSD research. It begins with an examination of the meaning of the term trauma, and of its specialised use within the clinical context and with respect to the concept of PTSD. The diagnostic approach to the detection of PTSD is presented, criteria in the DSM-IV-TR and the ICD-10 are summarised and differences between the two manuals are discussed. Arguments presented by critics of the concept of PTSD are presented and discussed. These concern the historical evolution of the concept, concerns about the universality of PTSD cross-culturally, and problems arising from understanding human suffering from a narrow medical perspective. It is concluded that while there are dangers in thinking of the sequelae of trauma as a medical/psychiatric problem, and while the alarming rate of traumatic events needs to be addressed at the political, economic and societal level, there is an important place for the provision of assessment and treatment of PTSD within a psychiatric/psychological clinical setting.
- Full Text:
- Date Issued: 2005
- Authors: Edwards, David J A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6228 , http://hdl.handle.net/10962/d1007778
- Description: This article introduces a special issue of the Journal of Psychology in Africa on post-traumatic stress disorder (PTSD) in Africa and particularly in South Africa and examines the critical debate that has surrounded PTSD research. It begins with an examination of the meaning of the term trauma, and of its specialised use within the clinical context and with respect to the concept of PTSD. The diagnostic approach to the detection of PTSD is presented, criteria in the DSM-IV-TR and the ICD-10 are summarised and differences between the two manuals are discussed. Arguments presented by critics of the concept of PTSD are presented and discussed. These concern the historical evolution of the concept, concerns about the universality of PTSD cross-culturally, and problems arising from understanding human suffering from a narrow medical perspective. It is concluded that while there are dangers in thinking of the sequelae of trauma as a medical/psychiatric problem, and while the alarming rate of traumatic events needs to be addressed at the political, economic and societal level, there is an important place for the provision of assessment and treatment of PTSD within a psychiatric/psychological clinical setting.
- Full Text:
- Date Issued: 2005
Evaluating parts-of-speech taggers for use in a text-to-scene conversion system
- Glass, Kevin R, Bangay, Shaun D
- Authors: Glass, Kevin R , Bangay, Shaun D
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432654 , vital:72890 , https://www.cs.ru.ac.za/research/groups/vrsig/currentprojects/053texttoscene/paper01.pdf
- Description: This paper presents parts-of-speech tagging as a first step towards an autonomous text-to-scene conversion system. It categorizes some freely available taggers, according to the techniques used by each in order to automatically identify word-classes. In addition, the performance of each identified tagger is verified experimentally. The SUSANNE corpus is used for testing and reveals the complexity of working with different tagsets, resulting in substantially lower accuracies in our tests than in those reported by the developers of each tagger. The taggers are then grouped to form a voting system to attempt to raise accuracies, but in no cases do the combined results improve upon the individual accuracies. Additionally a new metric, agreement, is tentatively proposed as an indication of confidence in the output of a group of taggers where such output cannot be validated.
- Full Text:
- Date Issued: 2005
- Authors: Glass, Kevin R , Bangay, Shaun D
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432654 , vital:72890 , https://www.cs.ru.ac.za/research/groups/vrsig/currentprojects/053texttoscene/paper01.pdf
- Description: This paper presents parts-of-speech tagging as a first step towards an autonomous text-to-scene conversion system. It categorizes some freely available taggers, according to the techniques used by each in order to automatically identify word-classes. In addition, the performance of each identified tagger is verified experimentally. The SUSANNE corpus is used for testing and reveals the complexity of working with different tagsets, resulting in substantially lower accuracies in our tests than in those reported by the developers of each tagger. The taggers are then grouped to form a voting system to attempt to raise accuracies, but in no cases do the combined results improve upon the individual accuracies. Additionally a new metric, agreement, is tentatively proposed as an indication of confidence in the output of a group of taggers where such output cannot be validated.
- Full Text:
- Date Issued: 2005
From trauma debriefing to trauma support: a South African experience of responding to individuals and communities in the aftermath of traumatising events
- Van Wyk, G, Edwards, David J A
- Authors: Van Wyk, G , Edwards, David J A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6267 , http://hdl.handle.net/10962/d1008266
- Description: This paper documents the approach and experience of Traumaclinic, a Cape Town based organisation offering a trauma support service. The controversy over single session debriefing interventions is examined and it is concluded that interventions that invite intense emotional expression should not be offered indiscriminately or forced on those who do not want them. When they do occur, they need to be carefully managed and take place over several sessions. A review of contemporary approaches to intervention following trauma highlights their comprehensive and flexible nature and the inclusion of multiple components that are introduced in a manner responsive to the needs of the situation. This is the basis of the current model used by Traumaclinic. The principles of that model are summarised and examples given of the application of the approach to specific cases.
- Full Text:
- Date Issued: 2005
- Authors: Van Wyk, G , Edwards, David J A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6267 , http://hdl.handle.net/10962/d1008266
- Description: This paper documents the approach and experience of Traumaclinic, a Cape Town based organisation offering a trauma support service. The controversy over single session debriefing interventions is examined and it is concluded that interventions that invite intense emotional expression should not be offered indiscriminately or forced on those who do not want them. When they do occur, they need to be carefully managed and take place over several sessions. A review of contemporary approaches to intervention following trauma highlights their comprehensive and flexible nature and the inclusion of multiple components that are introduced in a manner responsive to the needs of the situation. This is the basis of the current model used by Traumaclinic. The principles of that model are summarised and examples given of the application of the approach to specific cases.
- Full Text:
- Date Issued: 2005
Psychotherapy for post-traumatic stress disorder in a young rape survivor: a case study
- Authors: Labe, Dana
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6271 , http://hdl.handle.net/10962/d1008271
- Description: This paper describes the psychodynamic psychotherapy of a 20-year-old African woman with post-traumatic stress disorder (PTSD). ‘Mphumi’ entered therapy a year after her father’s friend had repeatedly raped her. The paper documents the process of therapy and uses the case material to examine theoretical issues relevant to the treatment of PTSD. First, Horowitz’s (2001) theory is used as a basis for arguing that a histrionic personality style predisposed her to an extreme degree of denial and dissociation, which prevented her from processing the trauma at a cognitive or emotional level and contributed to the entrenched PTSD. It was only after she had suffered a breakdown, which necessitated hospitalisation, that her resistance to processing the trauma was overcome. Second, the case material is used to show how other significantly disturbing events earlier in her life shaped her response to the rape and to examine the extent to which effective processing of the current trauma calls for the acknowledgement and working through of earlier traumas and losses. Finally, the case narrative shows how the treatment of PTSD is of necessity a slow, complex process which takes into account the individual’s unique history, idiosyncratic vulnerabilities and socio-cultural context
- Full Text:
- Date Issued: 2005
- Authors: Labe, Dana
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6271 , http://hdl.handle.net/10962/d1008271
- Description: This paper describes the psychodynamic psychotherapy of a 20-year-old African woman with post-traumatic stress disorder (PTSD). ‘Mphumi’ entered therapy a year after her father’s friend had repeatedly raped her. The paper documents the process of therapy and uses the case material to examine theoretical issues relevant to the treatment of PTSD. First, Horowitz’s (2001) theory is used as a basis for arguing that a histrionic personality style predisposed her to an extreme degree of denial and dissociation, which prevented her from processing the trauma at a cognitive or emotional level and contributed to the entrenched PTSD. It was only after she had suffered a breakdown, which necessitated hospitalisation, that her resistance to processing the trauma was overcome. Second, the case material is used to show how other significantly disturbing events earlier in her life shaped her response to the rape and to examine the extent to which effective processing of the current trauma calls for the acknowledgement and working through of earlier traumas and losses. Finally, the case narrative shows how the treatment of PTSD is of necessity a slow, complex process which takes into account the individual’s unique history, idiosyncratic vulnerabilities and socio-cultural context
- Full Text:
- Date Issued: 2005
The development phase of a case study of outcomes-based education assessment policy in the Human and Social Sciences learning area of C2005
- Authors: Wilmot, P Dianne
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6106 , http://hdl.handle.net/10962/d1009735
- Description: The second phase, the 'development phase' (January to December 2003), of an ongoing research project on policy implementation with specific reference to Grade 9 of the Human and Social Sciences (HSS) learning area of C2005 is described. More specifically, a journey, in which nine History and Geography teachers at two independent schools and one university lecturer, working collaboratively as an HSS research team, navigated their way through the national curriculum and assessment policy arena, pushed the boundaries of their own practice as reflexive practitioners, and implemented the first national application of the new General Education and Training Certificate (GETC), is outlined. The article consists of three sections. The first outlines and offers critical commentary on the national policy context in which the research was located, and in which all South African educators currently work. Drawing on national and international literature, it illuminates a number of issues pertinent to national policy enactment. The second section describes the Development Phase. It outlines two areas of curriculum innovation at the two schools, namely enquiry-based learning and the development of a learning process 'map', before honing in on Grade 9 CASS. Section three describes the implementation at the two schools of the HSS Common Tasks for Assessment (CTA) in October/November 2003. The conclusion synthesises the narrative.
- Full Text:
- Date Issued: 2005
- Authors: Wilmot, P Dianne
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6106 , http://hdl.handle.net/10962/d1009735
- Description: The second phase, the 'development phase' (January to December 2003), of an ongoing research project on policy implementation with specific reference to Grade 9 of the Human and Social Sciences (HSS) learning area of C2005 is described. More specifically, a journey, in which nine History and Geography teachers at two independent schools and one university lecturer, working collaboratively as an HSS research team, navigated their way through the national curriculum and assessment policy arena, pushed the boundaries of their own practice as reflexive practitioners, and implemented the first national application of the new General Education and Training Certificate (GETC), is outlined. The article consists of three sections. The first outlines and offers critical commentary on the national policy context in which the research was located, and in which all South African educators currently work. Drawing on national and international literature, it illuminates a number of issues pertinent to national policy enactment. The second section describes the Development Phase. It outlines two areas of curriculum innovation at the two schools, namely enquiry-based learning and the development of a learning process 'map', before honing in on Grade 9 CASS. Section three describes the implementation at the two schools of the HSS Common Tasks for Assessment (CTA) in October/November 2003. The conclusion synthesises the narrative.
- Full Text:
- Date Issued: 2005
The diet and ecological role of giraffe (Giraffa camelopardalis) introduced to the Eastern Cape, South Africa
- Parker, Daniel M, Bernard, Ric T F
- Authors: Parker, Daniel M , Bernard, Ric T F
- Date: 2005
- Subjects: Giraffe Giraffa camelopardalis Herbivore
- Language: English
- Type: Article
- Identifier: vital:6942 , http://hdl.handle.net/10962/d1011967
- Description: With an increase in the popularity of wildlife ranching in southern Africa has come the introduction of non-native (extralimital) mammalian herbivores. Financial gain has arguably been at the forefront of these introductions, with little or no assessment of the ecological consequences. The diet of three populations of introduced giraffe Giraffa camelopardalis was assessed by direct observation in the Eastern Cape Province, South Africa between January 2002 and October 2003, as the first step towards understanding the ecological role played by giraffe in the region. Similar to the diet of giraffe within their native range, a deciduous species from the genus Acacia (Acacia karroo) was the most important species in the diet. Giraffe in the Eastern Cape Province, however, consumed more evergreen species than those within their native range. The relative lack of deciduous species in the Eastern Cape Province provides a probable explanation for such a result. Seasonal variation in the consumption of the most important species in the diet was evident with members of the genus Rhus being more important in the winter months. This was attributed to the deciduous nature of A. karroo. The potential for giraffe to have a detrimental effect on the indigenous vegetation is discussed. We conclude that the study provides a much-needed list of plant species threatened by giraffe browsing in a region where the vegetation is thought to have evolved in the absence of such a browser.
- Full Text:
- Date Issued: 2005
- Authors: Parker, Daniel M , Bernard, Ric T F
- Date: 2005
- Subjects: Giraffe Giraffa camelopardalis Herbivore
- Language: English
- Type: Article
- Identifier: vital:6942 , http://hdl.handle.net/10962/d1011967
- Description: With an increase in the popularity of wildlife ranching in southern Africa has come the introduction of non-native (extralimital) mammalian herbivores. Financial gain has arguably been at the forefront of these introductions, with little or no assessment of the ecological consequences. The diet of three populations of introduced giraffe Giraffa camelopardalis was assessed by direct observation in the Eastern Cape Province, South Africa between January 2002 and October 2003, as the first step towards understanding the ecological role played by giraffe in the region. Similar to the diet of giraffe within their native range, a deciduous species from the genus Acacia (Acacia karroo) was the most important species in the diet. Giraffe in the Eastern Cape Province, however, consumed more evergreen species than those within their native range. The relative lack of deciduous species in the Eastern Cape Province provides a probable explanation for such a result. Seasonal variation in the consumption of the most important species in the diet was evident with members of the genus Rhus being more important in the winter months. This was attributed to the deciduous nature of A. karroo. The potential for giraffe to have a detrimental effect on the indigenous vegetation is discussed. We conclude that the study provides a much-needed list of plant species threatened by giraffe browsing in a region where the vegetation is thought to have evolved in the absence of such a browser.
- Full Text:
- Date Issued: 2005
Competition for attachment of aquaculture candidate probiotic and pathogenic bacteria on fish intestinal mucus:
- Vine, Niall G, Leukes, W D, Kaiser, Horst, Daya, Santylal, Baxter, Jeremy, Hecht, Thomas
- Authors: Vine, Niall G , Leukes, W D , Kaiser, Horst , Daya, Santylal , Baxter, Jeremy , Hecht, Thomas
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142819 , vital:38120 , DOI: 10.1111/j.1365-2761.2004.00542.x
- Description: Probiotics for aquaculture are generally only selected by their ability to produce antimicrobial metabolites; however, attachment to intestinal mucus is important in order to remain within the gut of its host. Five candidate probiotics (AP1–AP5), isolated from the clownfish, Amphiprion percula (Lacepéde), were examined for their ability to attach to fish intestinal mucus and compete with two pathogens, Aeromonas hydrophila and Vibrio alginolyticus. Two different radioactive isotopes were used to quantify competition between pathogens and probionts. Attachment of the pathogens was enhanced by the presence of the candidate probiotics. However, the addition of the candidate probiotics after the pathogens resulted in reduced pathogen attachment.
- Full Text:
- Date Issued: 2004
- Authors: Vine, Niall G , Leukes, W D , Kaiser, Horst , Daya, Santylal , Baxter, Jeremy , Hecht, Thomas
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142819 , vital:38120 , DOI: 10.1111/j.1365-2761.2004.00542.x
- Description: Probiotics for aquaculture are generally only selected by their ability to produce antimicrobial metabolites; however, attachment to intestinal mucus is important in order to remain within the gut of its host. Five candidate probiotics (AP1–AP5), isolated from the clownfish, Amphiprion percula (Lacepéde), were examined for their ability to attach to fish intestinal mucus and compete with two pathogens, Aeromonas hydrophila and Vibrio alginolyticus. Two different radioactive isotopes were used to quantify competition between pathogens and probionts. Attachment of the pathogens was enhanced by the presence of the candidate probiotics. However, the addition of the candidate probiotics after the pathogens resulted in reduced pathogen attachment.
- Full Text:
- Date Issued: 2004
Economic feasibility of an experimental octopus fishery in South Africa
- Authors: Oosthuizen, Ané
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6760 , http://hdl.handle.net/10962/d1007773
- Description: Octopus vulgaris was identified as a new marine resource to be commercially exploited through an experimental fishery. A recent policy on developing fisheries in South Africa emphasizes the importance of investigating the economic feasibility of a fishery as part of its management framework. The study reported here generated baseline information necessary in the design of the experimental fishery, giving guidelines as to which vessels, fishing gear and markets would be most feasible. The proposed fishery, gear and vessel type, fishing techniques and expected catch rates are described, the results of market research are outlined, and the cost of fishing is estimated. The potential business should consist of small and medium-sized vessels deploying unbaited pots attached to long lines. The longline pot fishery could be economically feasible, provided a 30 percent catch in 6600 pots/month is attained. Only existing, debt-free vessels should be used. The minimum catch per unit effort (CPUE) for various fishing operation scenarios was calculated to determine economic feasibility. This is an estimated minimum CPUE, based on assumptions that cannot be confirmed until the fishery starts. Furthermore, this economic analysis also needs to be assessed by stakeholders with experience of fishery operations , Rhodes Centenary issue of: South African Journal of Science.
- Full Text:
- Date Issued: 2004
- Authors: Oosthuizen, Ané
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6760 , http://hdl.handle.net/10962/d1007773
- Description: Octopus vulgaris was identified as a new marine resource to be commercially exploited through an experimental fishery. A recent policy on developing fisheries in South Africa emphasizes the importance of investigating the economic feasibility of a fishery as part of its management framework. The study reported here generated baseline information necessary in the design of the experimental fishery, giving guidelines as to which vessels, fishing gear and markets would be most feasible. The proposed fishery, gear and vessel type, fishing techniques and expected catch rates are described, the results of market research are outlined, and the cost of fishing is estimated. The potential business should consist of small and medium-sized vessels deploying unbaited pots attached to long lines. The longline pot fishery could be economically feasible, provided a 30 percent catch in 6600 pots/month is attained. Only existing, debt-free vessels should be used. The minimum catch per unit effort (CPUE) for various fishing operation scenarios was calculated to determine economic feasibility. This is an estimated minimum CPUE, based on assumptions that cannot be confirmed until the fishery starts. Furthermore, this economic analysis also needs to be assessed by stakeholders with experience of fishery operations , Rhodes Centenary issue of: South African Journal of Science.
- Full Text:
- Date Issued: 2004
Endothermy in African Platypleurine Cicadas: the influence of body size and habitat (Hemiptera: Cicadidae)
- Sanborn, Allen F, Villet, Martin H, Phillips, P K
- Authors: Sanborn, Allen F , Villet, Martin H , Phillips, P K
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:6925 , http://hdl.handle.net/10962/d1011912
- Description: The platypleurine cicadas have a wide distribution across Africa and southern Asia. We investigate endothermy as a thermoregulatory strategy in 11 South African species from five genera, with comparisons to the lone ectothermic platypleurine we found, in an attempt to ascertain any influence that habitat and/or body size have on the expression of endothermy in the platypleurine cicadas. Field measurements of body temperature (Tb) show that these animals regulate Tb through endogenous heat production. Heat production in the laboratory elevated Tb to the same range as in animals active in the field. Maximum Tb measured during calling activity when there was no access to solar radiation ranged from 13.2° to 22.3°C above ambient temperature in the five species measured. The mean Tb during activity without access to solar radiation did not differ from the mean Tb during diurnal activity. All platypleurines exhibit a unique behavior for cicadas while warming endogenously, a temperature- dependent telescoping pulsation of the abdomen that probably functions in ventilation. Platypleurines generally call from trunks and branches within the canopy and appear to rely on endothermy even when the sun is available to elevate Tb, in contrast to the facultative endothermy exhibited by New World endothermic species. The two exceptions to this generalization we found within the platypleurines are Platypleura wahlbergi and Albanycada albigera, which were the smallest species studied. The small size of P. wahlbergi appears to have altered their thermoregulatory strategy to one of facultative endothermy, whereby they use the sun when it is available to facilitate increases in Tb. Albanycada albigera is the only ectothermic platypleurine we found. The habitat and host plant association of A. albigera appear to have influenced the choice of ectothermy as a thermoregulatory strategy, as the species possesses the metabolic machinery to elevate to the Tb range observed in the endothermic species. Therefore, size and habitat appear to influence the expression of thermoregulatory strategies in African platypleurine cicadas.
- Full Text:
- Date Issued: 2004
- Authors: Sanborn, Allen F , Villet, Martin H , Phillips, P K
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:6925 , http://hdl.handle.net/10962/d1011912
- Description: The platypleurine cicadas have a wide distribution across Africa and southern Asia. We investigate endothermy as a thermoregulatory strategy in 11 South African species from five genera, with comparisons to the lone ectothermic platypleurine we found, in an attempt to ascertain any influence that habitat and/or body size have on the expression of endothermy in the platypleurine cicadas. Field measurements of body temperature (Tb) show that these animals regulate Tb through endogenous heat production. Heat production in the laboratory elevated Tb to the same range as in animals active in the field. Maximum Tb measured during calling activity when there was no access to solar radiation ranged from 13.2° to 22.3°C above ambient temperature in the five species measured. The mean Tb during activity without access to solar radiation did not differ from the mean Tb during diurnal activity. All platypleurines exhibit a unique behavior for cicadas while warming endogenously, a temperature- dependent telescoping pulsation of the abdomen that probably functions in ventilation. Platypleurines generally call from trunks and branches within the canopy and appear to rely on endothermy even when the sun is available to elevate Tb, in contrast to the facultative endothermy exhibited by New World endothermic species. The two exceptions to this generalization we found within the platypleurines are Platypleura wahlbergi and Albanycada albigera, which were the smallest species studied. The small size of P. wahlbergi appears to have altered their thermoregulatory strategy to one of facultative endothermy, whereby they use the sun when it is available to facilitate increases in Tb. Albanycada albigera is the only ectothermic platypleurine we found. The habitat and host plant association of A. albigera appear to have influenced the choice of ectothermy as a thermoregulatory strategy, as the species possesses the metabolic machinery to elevate to the Tb range observed in the endothermic species. Therefore, size and habitat appear to influence the expression of thermoregulatory strategies in African platypleurine cicadas.
- Full Text:
- Date Issued: 2004
Lessons Learned In The Global Deployment Of An Open Source Security Solution
- Authors: Irwin, Barry V W
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428830 , vital:72539 , https://digifors.cs.up.ac.za/issa/2004/Proceedings/Research/023.pdf
- Description: This paper covers the lessons learned, and the challenges facing the deployment of an Open Source derivative firewall and Virtual Private Network (VPN) solution into the established commercially driven Tele-communications arena. The lessons learned and issues discussed are drawn from the author’s own experiences having worked for a global Wireless Application Service Provider over a three year period. Focus is placed on the issues surrounding the integration of the open source equipment with that of the established global Telecommunications players, where compliance to existing network standards was a re-quirement for connectivity. Major stumbling blocks to the acceptance and success of the open source product were the concerns expressed by the Telecommunications Operators relating to interoperability and troubleshooting facilities when interfaced to their existing commercially available equipment and existing rigid telecommunications networks. The processes resulting in the initial decision to utilise an open source solution in preference to commercial offerings are also explored. An open source solution was found to offer higher flexibility and functionali-ty and greater return on investment whilst maintaining a significantly re-duced cost in comparison to commercial solutions available.
- Full Text:
- Date Issued: 2004
- Authors: Irwin, Barry V W
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428830 , vital:72539 , https://digifors.cs.up.ac.za/issa/2004/Proceedings/Research/023.pdf
- Description: This paper covers the lessons learned, and the challenges facing the deployment of an Open Source derivative firewall and Virtual Private Network (VPN) solution into the established commercially driven Tele-communications arena. The lessons learned and issues discussed are drawn from the author’s own experiences having worked for a global Wireless Application Service Provider over a three year period. Focus is placed on the issues surrounding the integration of the open source equipment with that of the established global Telecommunications players, where compliance to existing network standards was a re-quirement for connectivity. Major stumbling blocks to the acceptance and success of the open source product were the concerns expressed by the Telecommunications Operators relating to interoperability and troubleshooting facilities when interfaced to their existing commercially available equipment and existing rigid telecommunications networks. The processes resulting in the initial decision to utilise an open source solution in preference to commercial offerings are also explored. An open source solution was found to offer higher flexibility and functionali-ty and greater return on investment whilst maintaining a significantly re-duced cost in comparison to commercial solutions available.
- Full Text:
- Date Issued: 2004
‘The Gentle Art of Letting the Other Fellow Have Your Own Way': Viewpoints on a media narrative used to promote the proposed N2 toll road
- Farrington, Katie, Davies, Kate
- Authors: Farrington, Katie , Davies, Kate
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6098 , http://hdl.handle.net/10962/d1008628
- Description: This viewpoint paper is written in response to a South African National Roads Agency (SANRAL) advertorial published in various South African regional newspapers in February 2004. We highlight the importance of developing ‘media literacy’ – reading skills which enable the critical deconstruction of media texts. We explore, more specifically, the public relations strategies used by large corporations, and the media’s role as disseminators of corporate marketing material.We also look at the relevance in identifying the language and discourse positioning the writer, photographer, reader and their choice representative medium.
- Full Text:
- Date Issued: 2004
- Authors: Farrington, Katie , Davies, Kate
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6098 , http://hdl.handle.net/10962/d1008628
- Description: This viewpoint paper is written in response to a South African National Roads Agency (SANRAL) advertorial published in various South African regional newspapers in February 2004. We highlight the importance of developing ‘media literacy’ – reading skills which enable the critical deconstruction of media texts. We explore, more specifically, the public relations strategies used by large corporations, and the media’s role as disseminators of corporate marketing material.We also look at the relevance in identifying the language and discourse positioning the writer, photographer, reader and their choice representative medium.
- Full Text:
- Date Issued: 2004
Endothermy and chorusing behaviour in the African platypleurine cicada Pycna semiclara (Germar, 1834) (Hemiptera: Cicadidae)
- Villet, Martin H, Sanborn, Allen F, Phillips, P K
- Authors: Villet, Martin H , Sanborn, Allen F , Phillips, P K
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6892 , http://hdl.handle.net/10962/d1011652 , http://dx.doi.org/10.1139/z03-119
- Description: Cicadas use acoustic signals to find mates and therefore offer a phylogenetically independent opportunity to test the generality of ideas about acoustic communication that were developed from studies of other animals. Pycna semiclara (Germar, 1834) (Hemiptera: Cicadidae) is a forest-dwelling platypleurine cicada that uses its calling song to form choruses and attract mates. Additionally, P. semiclara produces an encounter call that is involved in courtship and also in spacing males within choruses. Males generally call from exposed trunks and branches within the understory but clear of the undergrowth and fight with other males that call within about 50 cm of them. Choruses sing sporadically throughout the day but focus most of their calling activity into half-hour bouts at dawn and dusk. Body size and ambient temperature had no significant effect on spectral or temporal characteristics of the calling song. Body temperature measurements indicate that P. semiclara thermoregulates endothermically, with a body temperature of more than 22 °C above ambient temperature being measured during calling activity at dusk. Such endothermy provides an advantage to the cicadas by allowing them to call during crepuscular hours when atmospheric conditions are most optimal for acoustic communication and predation risks are minimal. Coincidentally, endogenously regulating body temperature allows the temporal characteristics of the call to be unaffected by ambient temperature changes.
- Full Text:
- Date Issued: 2003
- Authors: Villet, Martin H , Sanborn, Allen F , Phillips, P K
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6892 , http://hdl.handle.net/10962/d1011652 , http://dx.doi.org/10.1139/z03-119
- Description: Cicadas use acoustic signals to find mates and therefore offer a phylogenetically independent opportunity to test the generality of ideas about acoustic communication that were developed from studies of other animals. Pycna semiclara (Germar, 1834) (Hemiptera: Cicadidae) is a forest-dwelling platypleurine cicada that uses its calling song to form choruses and attract mates. Additionally, P. semiclara produces an encounter call that is involved in courtship and also in spacing males within choruses. Males generally call from exposed trunks and branches within the understory but clear of the undergrowth and fight with other males that call within about 50 cm of them. Choruses sing sporadically throughout the day but focus most of their calling activity into half-hour bouts at dawn and dusk. Body size and ambient temperature had no significant effect on spectral or temporal characteristics of the calling song. Body temperature measurements indicate that P. semiclara thermoregulates endothermically, with a body temperature of more than 22 °C above ambient temperature being measured during calling activity at dusk. Such endothermy provides an advantage to the cicadas by allowing them to call during crepuscular hours when atmospheric conditions are most optimal for acoustic communication and predation risks are minimal. Coincidentally, endogenously regulating body temperature allows the temporal characteristics of the call to be unaffected by ambient temperature changes.
- Full Text:
- Date Issued: 2003
Review of South African research on volcanic and related rocks and mantle-derived materials : 1999-2002
- Authors: Marsh, Julian S
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6737 , http://hdl.handle.net/10962/d1007550
- Description: This report reviews South African research relating to the scientific interests of the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) and which was published between 1999 and 2002. The focus is on published work and does not include conference presentations and abstract volumes or other informal documents.
- Full Text:
- Date Issued: 2003
- Authors: Marsh, Julian S
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6737 , http://hdl.handle.net/10962/d1007550
- Description: This report reviews South African research relating to the scientific interests of the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) and which was published between 1999 and 2002. The focus is on published work and does not include conference presentations and abstract volumes or other informal documents.
- Full Text:
- Date Issued: 2003