A technique for evaluating species richness maps generated from collections data
- Robertson, Mark P, Barker, Nigel P
- Authors: Robertson, Mark P , Barker, Nigel P
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6538 , http://hdl.handle.net/10962/d1005979
- Description: There is considerable pressure on conservation planners to use existing data from herbarium and museum collections for planning and monitoring, despite the weaknesses of such data. It is thus important to be able to assess the quality of this information. One application of these data is the production of species richness maps. However, sampling effort is generally not consistent throughout a region for maps generated from collections data, and it is thus desirable to identify geographic grid cells (such as quarter degree squares: QDS) for which there has been low sampling effort. We describe a technique that can be used to identify QDS that are likely to have low species richness that is due to insufficient sampling effort rather than to low actual species richness. The technique exploits relationships between climate and species richness to detect QDS that are poorly sampled. This approach offers advantages over the current practice of applying a single threshold across the entire map region to detectQDSthat are poorly sampled. Here we report on the application of our technique to plant species richness data in the PRECIS database. Results reveal that the majority of QDS in the Flora of Southern Africa region can be considered to be poorly sampled, even when using conservative thresholds for richness values. The advantages and weaknesses of the technique are discussed and issues requiring further investigation are highlighted.
- Full Text:
- Date Issued: 2006
- Authors: Robertson, Mark P , Barker, Nigel P
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6538 , http://hdl.handle.net/10962/d1005979
- Description: There is considerable pressure on conservation planners to use existing data from herbarium and museum collections for planning and monitoring, despite the weaknesses of such data. It is thus important to be able to assess the quality of this information. One application of these data is the production of species richness maps. However, sampling effort is generally not consistent throughout a region for maps generated from collections data, and it is thus desirable to identify geographic grid cells (such as quarter degree squares: QDS) for which there has been low sampling effort. We describe a technique that can be used to identify QDS that are likely to have low species richness that is due to insufficient sampling effort rather than to low actual species richness. The technique exploits relationships between climate and species richness to detect QDS that are poorly sampled. This approach offers advantages over the current practice of applying a single threshold across the entire map region to detectQDSthat are poorly sampled. Here we report on the application of our technique to plant species richness data in the PRECIS database. Results reveal that the majority of QDS in the Flora of Southern Africa region can be considered to be poorly sampled, even when using conservative thresholds for richness values. The advantages and weaknesses of the technique are discussed and issues requiring further investigation are highlighted.
- Full Text:
- Date Issued: 2006
Cognitive pharmaceutical services and the community pharmacist: are South African patients receiving them and are they willing to pay?
- Hill, Peter W, Dowse, Roslind
- Authors: Hill, Peter W , Dowse, Roslind
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156829 , vital:40054 , DOI 10.1211/ijpp.15.2.0007
- Description: The objectives of this study were to ascertain the opinions of randomly selected South African medical aid members regarding the provision by community pharmacists of patient counselling and information; member satisfaction with pharmacist services; their rating of pharmacist accessibility; and if pharmacists should be reimbursed for providing cognitive pharmaceutical services. Setting A South African private healthcare insurance company.
- Full Text:
- Date Issued: 2006
- Authors: Hill, Peter W , Dowse, Roslind
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156829 , vital:40054 , DOI 10.1211/ijpp.15.2.0007
- Description: The objectives of this study were to ascertain the opinions of randomly selected South African medical aid members regarding the provision by community pharmacists of patient counselling and information; member satisfaction with pharmacist services; their rating of pharmacist accessibility; and if pharmacists should be reimbursed for providing cognitive pharmaceutical services. Setting A South African private healthcare insurance company.
- Full Text:
- Date Issued: 2006
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
Nestmate recognition and genetic variability among individuals from nests of the queenless ponerine ant, Streblognathus aethiopicus Smith (Hymenoptera: Formicidae)
- Schluns, E A, Neumann, Peter, Schluns, H, Hepburn, H Randall, Moritz, Robin F A
- Authors: Schluns, E A , Neumann, Peter , Schluns, H , Hepburn, H Randall , Moritz, Robin F A
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452000 , vital:75094 , https://hdl.handle.net/10520/EJC32667
- Description: Nestmate recognition in the queenless ponerine ant, Streblognathus aethiopicus, was evaluated with a behavioural bioassay. Ten pairs of nests were randomly chosen from an aggregation of 74 nests. While nestmates never showed aggression towards each other, the behaviour towards non-nestmates was either aggressive or non-aggressive, demonstrating the ability to recognize nestmates. Also, the nests in this aggregation were evenly spaced, further supporting the notion of territoriality in this species. To evaluate the relative importance of environment and genetics on the observed variation in nestmate recognition, we measured the spatial and genetic distances between nests. Workers of 13 nests were genotyped with the AFLP technique. Multiple regression analysis revealed no significant impact of spatial and genetic distance on aggressive behaviour. Thus, further studies are necessary to reveal the actual mechanisms underlying nestmate recognition in this species. Two distinct groups of nests with genetically homogeneous and heterogeneous workers were found, which may indicate gamergate replacement or colony fission.
- Full Text:
- Date Issued: 2006
- Authors: Schluns, E A , Neumann, Peter , Schluns, H , Hepburn, H Randall , Moritz, Robin F A
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452000 , vital:75094 , https://hdl.handle.net/10520/EJC32667
- Description: Nestmate recognition in the queenless ponerine ant, Streblognathus aethiopicus, was evaluated with a behavioural bioassay. Ten pairs of nests were randomly chosen from an aggregation of 74 nests. While nestmates never showed aggression towards each other, the behaviour towards non-nestmates was either aggressive or non-aggressive, demonstrating the ability to recognize nestmates. Also, the nests in this aggregation were evenly spaced, further supporting the notion of territoriality in this species. To evaluate the relative importance of environment and genetics on the observed variation in nestmate recognition, we measured the spatial and genetic distances between nests. Workers of 13 nests were genotyped with the AFLP technique. Multiple regression analysis revealed no significant impact of spatial and genetic distance on aggressive behaviour. Thus, further studies are necessary to reveal the actual mechanisms underlying nestmate recognition in this species. Two distinct groups of nests with genetically homogeneous and heterogeneous workers were found, which may indicate gamergate replacement or colony fission.
- 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
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