Indigenous People’s Detection of Rapid Ecological Change
- Lauer, Matthew, Aswani, Shankar
- Authors: Lauer, Matthew , Aswani, Shankar
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124811 , vital:35699 , https://doi.10.1111/cobi.12250
- Description: When sudden catastrophic events occur, it becomes critical for coastal communities to detect and respond to environmental transformations because failure to do so may undermine overall ecosystem resilience and threaten people’s livelihoods. We therefore asked how capable of detecting rapid ecological change following massive environmental disruptions local, indigenous people are. We assessed the direction and periodicity of experimental learning of people in the Western Solomon Islands after a tsunami in 2007. We compared the results of marine science surveys with local ecological knowledge of the benthos across 3 affected villages and 3 periods before and after the tsunami. We sought to determine how people recognize biophysical changes in the environment before and after catastrophic events such as earthquakes and tsunamis and whether people have the ability to detect ecological changes over short time scales or need longer time scales to recognize changes. Indigenous people were able to detect changes in the benthos over time. Detection levels differed between marine science surveys and local ecological knowledge sources over time, but overall patterns of statistically significant detection of change were evident for various habitats. Our findings have implications for marine conservation, coastal management policies, and disaster-relief efforts because when people are able to detect ecological changes, this, in turn, affects how they exploit and manage their marine resources.
- Full Text:
- Date Issued: 2014
- Authors: Lauer, Matthew , Aswani, Shankar
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124811 , vital:35699 , https://doi.10.1111/cobi.12250
- Description: When sudden catastrophic events occur, it becomes critical for coastal communities to detect and respond to environmental transformations because failure to do so may undermine overall ecosystem resilience and threaten people’s livelihoods. We therefore asked how capable of detecting rapid ecological change following massive environmental disruptions local, indigenous people are. We assessed the direction and periodicity of experimental learning of people in the Western Solomon Islands after a tsunami in 2007. We compared the results of marine science surveys with local ecological knowledge of the benthos across 3 affected villages and 3 periods before and after the tsunami. We sought to determine how people recognize biophysical changes in the environment before and after catastrophic events such as earthquakes and tsunamis and whether people have the ability to detect ecological changes over short time scales or need longer time scales to recognize changes. Indigenous people were able to detect changes in the benthos over time. Detection levels differed between marine science surveys and local ecological knowledge sources over time, but overall patterns of statistically significant detection of change were evident for various habitats. Our findings have implications for marine conservation, coastal management policies, and disaster-relief efforts because when people are able to detect ecological changes, this, in turn, affects how they exploit and manage their marine resources.
- Full Text:
- Date Issued: 2014
Investigations of growth metrics and δ15N values of water hyacinth (Eichhornia crassipes,(Mart.) Solms-Laub) in relation to biological control
- Authors: Hill, Jaclyn M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444758 , vital:74265 , https://doi.org/10.1016/j.aquabot.2013.12.001
- Description: The success of biological control for Eichhornia crassipes (Mart) Solms-Laub has been varied, with failure attributed to various factors including increased eutrophication in freshwater systems. Studies have shown that high N-loads are associated with enriched δ15N values of aquatic biota. Stable isotope analyses may help to assess the nutrient status of invaded ecosystems and predict the success of classical biological control. A combination of controlled greenhouse experiments and in situ observations were used to quantify the δ15N equilibration rate of E. crassipes leaf tissue (i.e. the time span of the information on environmental N-loading), confirm the ability of plant tissue to reflect ecosystem N-loading and to compare standard water hyacinth growth metrics with δ15N and C/N ratios to evaluate how well they described eutrophication. Using both δ15N values and C/N ratios, it was possible to clearly distinguish between manure, fertilizer and control regimes and plant tissue provided information on ecosystem N loading over approximately 16 days.
- Full Text:
- Date Issued: 2014
- Authors: Hill, Jaclyn M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444758 , vital:74265 , https://doi.org/10.1016/j.aquabot.2013.12.001
- Description: The success of biological control for Eichhornia crassipes (Mart) Solms-Laub has been varied, with failure attributed to various factors including increased eutrophication in freshwater systems. Studies have shown that high N-loads are associated with enriched δ15N values of aquatic biota. Stable isotope analyses may help to assess the nutrient status of invaded ecosystems and predict the success of classical biological control. A combination of controlled greenhouse experiments and in situ observations were used to quantify the δ15N equilibration rate of E. crassipes leaf tissue (i.e. the time span of the information on environmental N-loading), confirm the ability of plant tissue to reflect ecosystem N-loading and to compare standard water hyacinth growth metrics with δ15N and C/N ratios to evaluate how well they described eutrophication. Using both δ15N values and C/N ratios, it was possible to clearly distinguish between manure, fertilizer and control regimes and plant tissue provided information on ecosystem N loading over approximately 16 days.
- Full Text:
- Date Issued: 2014
Leadership for biodiversity in South Africa transformation and capacity development in the GreenMatter programme
- Authors: Rosenberg, Eureta
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437190 , vital:73351 , ISBN 978-9086862528 , https://doi.org/10.3920/978-90-8686-802-5_18
- Description: As we begin to write this chapter, it is only a few hours since the news broke about the passing of Nelson Mandela, the founding president of a democratic South Africa. As we de-scribe our work in supporting intergenerational learning and the development of transformational leadership, it seems appro-priate to make this reference as a tribute to him. This work would not have been possible without the contribution of Man-dela and all who fought for justice and an egalitarian society in South Africa. We are able to write about the so-called ‘born frees’ because of Mandela’s role in dismantling apartheid, a system that sought to condemn black people to perpetual ser-vitude, ignorance and poverty. Indeed, our efforts in building skills for biodiversity, under the auspices of GreenMatter, are inspired by his courageous leadership, his selflessness, com-mitment to education and love of people, knowledge and na-ture. While philosophies, contexts and methods will vary, the quest of all intergenerational learning is to build a bridge that enables young people to learn from the experiences and wisdom of previous generations.
- Full Text:
- Date Issued: 2014
- Authors: Rosenberg, Eureta
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437190 , vital:73351 , ISBN 978-9086862528 , https://doi.org/10.3920/978-90-8686-802-5_18
- Description: As we begin to write this chapter, it is only a few hours since the news broke about the passing of Nelson Mandela, the founding president of a democratic South Africa. As we de-scribe our work in supporting intergenerational learning and the development of transformational leadership, it seems appro-priate to make this reference as a tribute to him. This work would not have been possible without the contribution of Man-dela and all who fought for justice and an egalitarian society in South Africa. We are able to write about the so-called ‘born frees’ because of Mandela’s role in dismantling apartheid, a system that sought to condemn black people to perpetual ser-vitude, ignorance and poverty. Indeed, our efforts in building skills for biodiversity, under the auspices of GreenMatter, are inspired by his courageous leadership, his selflessness, com-mitment to education and love of people, knowledge and na-ture. While philosophies, contexts and methods will vary, the quest of all intergenerational learning is to build a bridge that enables young people to learn from the experiences and wisdom of previous generations.
- Full Text:
- Date Issued: 2014
Ontogenetic and seasonal shifts in the diet of Diplodus cervinus hottentotus (Pisces: Sparidae) in southern Angola
- Winkler, Alexander C, Santos, Carmen V D, Potts, Warren M
- Authors: Winkler, Alexander C , Santos, Carmen V D , Potts, Warren M
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125452 , vital:35784 , https://doi.10.2989/1814232X.2014.951392
- Description: Fishes of the family Sparidae occupy a diverse range of trophic niches, from herbivores to generalist omnivores and specialist predators (Hanel and Tsigenopoulos 2011). Feeding specialisation in this family is facilitated by diversity in tooth type and anterior jaw arrangement (Vandewalle et al. 1995). Other fish families, such as Cyprinidae and Labridae, have developed crushing pharyngeal teeth to process their food. Sparids, however, have retained a simple pharyngeal tooth arrangement and instead have developed molariform teeth to process hard-shelled molluscs and invertebrate prey. Hanel and Tsigenopoulos (2011) suggested that this alternate strategy is a major factor facilitating the trophic diversity in sparid fishes.
- Full Text:
- Date Issued: 2014
- Authors: Winkler, Alexander C , Santos, Carmen V D , Potts, Warren M
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125452 , vital:35784 , https://doi.10.2989/1814232X.2014.951392
- Description: Fishes of the family Sparidae occupy a diverse range of trophic niches, from herbivores to generalist omnivores and specialist predators (Hanel and Tsigenopoulos 2011). Feeding specialisation in this family is facilitated by diversity in tooth type and anterior jaw arrangement (Vandewalle et al. 1995). Other fish families, such as Cyprinidae and Labridae, have developed crushing pharyngeal teeth to process their food. Sparids, however, have retained a simple pharyngeal tooth arrangement and instead have developed molariform teeth to process hard-shelled molluscs and invertebrate prey. Hanel and Tsigenopoulos (2011) suggested that this alternate strategy is a major factor facilitating the trophic diversity in sparid fishes.
- Full Text:
- Date Issued: 2014
Review: Recent theorisations of trauma fiction, postcolonialism, and the south African novel
- Authors: Njovane, Thando
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/458635 , vital:75757 , https://hdl.handle.net/10520/EJC156467
- Description: Drawing on both psychological and sociological definitions of trauma, the essay collection The Splintered Glass engages with the intersection between individual and cultural trauma, while simultaneously warning against the blurring of the distinction between the two. In line with this, trauma is defined not only as a "wound of the mind" of an individual, but also as a "link between cultures" (x). While bearing a remarkable resemblance to the Freudian haunting inherent in most definitions of historical trauma (see also Erikson, Tal and Caruth), the concept of cultural trauma, as utilised in this collection, is situated in the present and seeks to transcend this haunting by gesturing towards a "safe post-traumatic space" (6). A traumatic history "established and sustained by power structures, social agents and contending groups" in a "constant, recurrent struggle that stirs up a troubling memory" (xii) is shared by many, if not all, postcolonial societies.
- Full Text:
- Date Issued: 2014
- Authors: Njovane, Thando
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/458635 , vital:75757 , https://hdl.handle.net/10520/EJC156467
- Description: Drawing on both psychological and sociological definitions of trauma, the essay collection The Splintered Glass engages with the intersection between individual and cultural trauma, while simultaneously warning against the blurring of the distinction between the two. In line with this, trauma is defined not only as a "wound of the mind" of an individual, but also as a "link between cultures" (x). While bearing a remarkable resemblance to the Freudian haunting inherent in most definitions of historical trauma (see also Erikson, Tal and Caruth), the concept of cultural trauma, as utilised in this collection, is situated in the present and seeks to transcend this haunting by gesturing towards a "safe post-traumatic space" (6). A traumatic history "established and sustained by power structures, social agents and contending groups" in a "constant, recurrent struggle that stirs up a troubling memory" (xii) is shared by many, if not all, postcolonial societies.
- Full Text:
- Date Issued: 2014
The role of reflection and new ideas in the advancement of a strong and responsive democratic system
- Authors: Badat, Saleem
- Date: 2013-09-25
- Language: English
- Type: Text
- Identifier: vital:7921 , http://hdl.handle.net/10962/d1016471
- Full Text:
- Date Issued: 2013-09-25
The role of reflection and new ideas in the advancement of a strong and responsive democratic system
- Authors: Badat, Saleem
- Date: 2013-09-25
- Language: English
- Type: Text
- Identifier: vital:7921 , http://hdl.handle.net/10962/d1016471
- Full Text:
- Date Issued: 2013-09-25
Knockdown of Hop downregulates RhoC expression, and decreases pseudopodia formation and migration in cancer cell lines:
- Willmer, Tarryn, Contu, Lara, Blatch, Gregory L, Edkins, Adrienne L
- Authors: Willmer, Tarryn , Contu, Lara , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165196 , vital:41217 , DOI: 10.1016/j.canlet.2012.09.021
- Description: The Hsp90/Hsp70 organising protein (Hop) is a co-chaperone that mediates the interaction of Hsp90 and Hsp70 molecular chaperones during assembly of Hsp90 complexes in cells. Formation of Hsp90 complexes is a key intermediate step in the maturation and homeostasis of oncoproteins and several hormone receptors. In this paper, we demonstrate that knockdown of Hop decreased migration of Hs578T and MDA-MB-231 breast cancer cells. Hop was identified in isolated pseudopodia fractions; it colocalised with actin in lamellipodia, and co-sedimented with purified actin in vitro. Knockdown of Hop caused a decrease in the level of RhoC GTPase, and significantly inhibited pseudopodia formation in Hs578T cells. Our data suggest that Hop regulates directional cell migration by multiple unknown mechanisms.
- Full Text:
- Date Issued: 2013
- Authors: Willmer, Tarryn , Contu, Lara , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165196 , vital:41217 , DOI: 10.1016/j.canlet.2012.09.021
- Description: The Hsp90/Hsp70 organising protein (Hop) is a co-chaperone that mediates the interaction of Hsp90 and Hsp70 molecular chaperones during assembly of Hsp90 complexes in cells. Formation of Hsp90 complexes is a key intermediate step in the maturation and homeostasis of oncoproteins and several hormone receptors. In this paper, we demonstrate that knockdown of Hop decreased migration of Hs578T and MDA-MB-231 breast cancer cells. Hop was identified in isolated pseudopodia fractions; it colocalised with actin in lamellipodia, and co-sedimented with purified actin in vitro. Knockdown of Hop caused a decrease in the level of RhoC GTPase, and significantly inhibited pseudopodia formation in Hs578T cells. Our data suggest that Hop regulates directional cell migration by multiple unknown mechanisms.
- Full Text:
- Date Issued: 2013
Real-time distributed malicious traffic monitoring for honeypots and network telescopes
- Hunter, Samuel O, Irwin, Barry V W, Stalmans, Etienne
- Authors: Hunter, Samuel O , Irwin, Barry V W , Stalmans, Etienne
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429660 , vital:72630 , 10.1109/ISSA.2013.6641050
- Description: Network telescopes and honeypots have been used with great success to record malicious network traffic for analysis, however, this is often done off-line well after the traffic was observed. This has left us with only a cursory understanding of malicious hosts and no knowledge of the software they run, uptime or other malicious activity they may have participated in. This work covers a messaging framework (rDSN) that was developed to allow for the real-time analysis of malicious traffic. This data was captured from multiple, distributed honeypots and network telescopes. Data was collected over a period of two months from these data sensors. Using this data new techniques for malicious host analysis and re-identification in dynamic IP address space were explored. An Automated Reconnaissance (AR) Framework was developed to aid the process of data collection, this framework was responsible for gathering information from malicious hosts through both passive and active fingerprinting techniques. From the analysis of this data; correlations between malicious hosts were identified based on characteristics such as Operating System, targeted service, location and services running on the malicious hosts. An initial investigation in Latency Based Multilateration (LBM), a novel technique to assist in host re-identification was tested and proved successful as a supporting metric for host re-identification.
- Full Text:
- Date Issued: 2013
- Authors: Hunter, Samuel O , Irwin, Barry V W , Stalmans, Etienne
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429660 , vital:72630 , 10.1109/ISSA.2013.6641050
- Description: Network telescopes and honeypots have been used with great success to record malicious network traffic for analysis, however, this is often done off-line well after the traffic was observed. This has left us with only a cursory understanding of malicious hosts and no knowledge of the software they run, uptime or other malicious activity they may have participated in. This work covers a messaging framework (rDSN) that was developed to allow for the real-time analysis of malicious traffic. This data was captured from multiple, distributed honeypots and network telescopes. Data was collected over a period of two months from these data sensors. Using this data new techniques for malicious host analysis and re-identification in dynamic IP address space were explored. An Automated Reconnaissance (AR) Framework was developed to aid the process of data collection, this framework was responsible for gathering information from malicious hosts through both passive and active fingerprinting techniques. From the analysis of this data; correlations between malicious hosts were identified based on characteristics such as Operating System, targeted service, location and services running on the malicious hosts. An initial investigation in Latency Based Multilateration (LBM), a novel technique to assist in host re-identification was tested and proved successful as a supporting metric for host re-identification.
- Full Text:
- Date Issued: 2013
Residency and small-scale movement behaviour of three endemic sparid fishes in their shallow rocky subtidal nursery habitat, South Africa
- Watt-Pringle, Peter A, Cowley, Paul D, Götz, Albrecht
- Authors: Watt-Pringle, Peter A , Cowley, Paul D , Götz, Albrecht
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443584 , vital:74135 , https://hdl.handle.net/10520/EJC137608
- Description: The residency and small-scale movements of early juveniles (175 mm fork length) of three sparid fish species were examined in the shallow subtidal zone along a 500 m stretch of rocky coastline near Schoenmakerskop (Eastern Cape Province, South Africa). A total of 12 blacktail (Diplodus capensis), 12 zebra (Diplodus hottentotus) and six white musselcracker (Sparodon durbanensis) were tagged using visible implant elastomer (VIE) tags. Underwater observations in four shallow rocky subtidal gullies and adjacent areas were made using snorkelling gear on a total of 37 days spanning 13 field trips over spring low tide periods between January and August 2006. The VIE tagging method was well suited to individually tag small juvenile fish with minimum disturbance. In general, the degree of residency of juveniles in the shallow rocky subtidal zone was species specific and dependent on the size of individuals. Juvenile zebra displayed the highest degree of residency followed by white musselcracker and blacktail, with re-sightings recorded on 53%, 40% and 10% of observation days, respectively. The high degree of residency by early juvenile sparids renders them vulnerable to localized coastal perturbations and climate change.
- Full Text:
- Date Issued: 2013
- Authors: Watt-Pringle, Peter A , Cowley, Paul D , Götz, Albrecht
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443584 , vital:74135 , https://hdl.handle.net/10520/EJC137608
- Description: The residency and small-scale movements of early juveniles (175 mm fork length) of three sparid fish species were examined in the shallow subtidal zone along a 500 m stretch of rocky coastline near Schoenmakerskop (Eastern Cape Province, South Africa). A total of 12 blacktail (Diplodus capensis), 12 zebra (Diplodus hottentotus) and six white musselcracker (Sparodon durbanensis) were tagged using visible implant elastomer (VIE) tags. Underwater observations in four shallow rocky subtidal gullies and adjacent areas were made using snorkelling gear on a total of 37 days spanning 13 field trips over spring low tide periods between January and August 2006. The VIE tagging method was well suited to individually tag small juvenile fish with minimum disturbance. In general, the degree of residency of juveniles in the shallow rocky subtidal zone was species specific and dependent on the size of individuals. Juvenile zebra displayed the highest degree of residency followed by white musselcracker and blacktail, with re-sightings recorded on 53%, 40% and 10% of observation days, respectively. The high degree of residency by early juvenile sparids renders them vulnerable to localized coastal perturbations and climate change.
- Full Text:
- Date Issued: 2013
Section 40 of the Consumer Protection Act in comparative perspective: aantekeninge
- Authors: Glover, Graham B
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70527 , vital:29672 , https://hdl.handle.net/10520/EJC144971
- Description: The purpose of this comment is to consider some of the problems with how we are to understand the role and purpose of section 40 of South Africa's Consumer Protection Act 68 of 2008 when viewed from a doctrinal perspective. Section 40 has the heading "Unconscionable conduct", and contains three subsections.
- Full Text: false
- Date Issued: 2013
- Authors: Glover, Graham B
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70527 , vital:29672 , https://hdl.handle.net/10520/EJC144971
- Description: The purpose of this comment is to consider some of the problems with how we are to understand the role and purpose of section 40 of South Africa's Consumer Protection Act 68 of 2008 when viewed from a doctrinal perspective. Section 40 has the heading "Unconscionable conduct", and contains three subsections.
- Full Text: false
- Date Issued: 2013
Towards a GPU accelerated virtual machine for massively parallel packet classification and filtering
- Nottingham, Alastair, Irwin, Barry V W
- Authors: Nottingham, Alastair , Irwin, Barry V W
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430295 , vital:72681 , https://doi.org/10.1145/2513456.2513504
- Description: This paper considers the application of GPU co-processors to accelerate the analysis of packet data, particularly within extremely large packet traces spanning months or years of traffic. Discussion focuses on the construction, performance and limitations of the experimental GPF (GPU Packet Filter), which employs a prototype massively-parallel protocol-independent multi-match algorithm to rapidly compare packets against multiple arbitrary filters. The paper concludes with a consideration of mechanisms to expand the flexibility and power of the GPF algorithm to construct a fully programmable GPU packet classification virtual machine, which can perform massively parallel classification, data-mining and data-transformation to explore and analyse packet traces. This virtual machine is a component of a larger framework of capture analysis tools which together provide capture indexing, manipulation, filtering and visualisation functions.
- Full Text:
- Date Issued: 2013
Towards a GPU accelerated virtual machine for massively parallel packet classification and filtering
- Authors: Nottingham, Alastair , Irwin, Barry V W
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430295 , vital:72681 , https://doi.org/10.1145/2513456.2513504
- Description: This paper considers the application of GPU co-processors to accelerate the analysis of packet data, particularly within extremely large packet traces spanning months or years of traffic. Discussion focuses on the construction, performance and limitations of the experimental GPF (GPU Packet Filter), which employs a prototype massively-parallel protocol-independent multi-match algorithm to rapidly compare packets against multiple arbitrary filters. The paper concludes with a consideration of mechanisms to expand the flexibility and power of the GPF algorithm to construct a fully programmable GPU packet classification virtual machine, which can perform massively parallel classification, data-mining and data-transformation to explore and analyse packet traces. This virtual machine is a component of a larger framework of capture analysis tools which together provide capture indexing, manipulation, filtering and visualisation functions.
- Full Text:
- Date Issued: 2013
Capturefoundry: a gpu accelerated packet capture analysis tool
- Nottingham, Alastair, Richter, John, Irwin, Barry V W
- Authors: Nottingham, Alastair , Richter, John , Irwin, Barry V W
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430112 , vital:72666 , https://doi.org/10.1145/2389836.2389877
- Description: Packet captures are used to support a variety of tasks, including network administration, fault diagnosis and security and network related research. Despite their usefulness, processing packet capture files is a slow and tedious process that impedes the analysis of large, long-term captures. This paper discusses the primary components and observed performance of CaptureFoundry, a stand-alone capture analysis support tool designed to quickly map, filter and extract packets from large capture files using a combination of indexing techniques and GPU accelerated packet classification. All results are persistent, and may be used to rapidly extract small pre-filtered captures on demand that may be analysed quickly in existing capture analysis applications. Performance results show that CaptureFoundry is capable of generating multiple indexes and classification results for large captures at hundreds of megabytes per second, with minimal CPU and memory overhead and only minor additional storage space requirements.
- Full Text:
- Date Issued: 2012
- Authors: Nottingham, Alastair , Richter, John , Irwin, Barry V W
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430112 , vital:72666 , https://doi.org/10.1145/2389836.2389877
- Description: Packet captures are used to support a variety of tasks, including network administration, fault diagnosis and security and network related research. Despite their usefulness, processing packet capture files is a slow and tedious process that impedes the analysis of large, long-term captures. This paper discusses the primary components and observed performance of CaptureFoundry, a stand-alone capture analysis support tool designed to quickly map, filter and extract packets from large capture files using a combination of indexing techniques and GPU accelerated packet classification. All results are persistent, and may be used to rapidly extract small pre-filtered captures on demand that may be analysed quickly in existing capture analysis applications. Performance results show that CaptureFoundry is capable of generating multiple indexes and classification results for large captures at hundreds of megabytes per second, with minimal CPU and memory overhead and only minor additional storage space requirements.
- Full Text:
- Date Issued: 2012
Inter-seasonal persistence and size-structuring of two minnow species within headwater streams in the Eastern Cape, South Africa
- Kadye, Wilbert T, Booth, Anthony J
- Authors: Kadye, Wilbert T , Booth, Anthony J
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124866 , vital:35705 , https://doi.10.1111/j.1439-0426.2012.02027.x
- Description: This study examined temporal variation in population dynamics and size structuring of two cyprinid minnows, Pseudobarbus afer and Barbus anoplus, in relation to their proximate physical habitats. Population estimates were determined using three-pass depletion sampling during both summer and winter. The habitats were characterised by seasonal variation in all physico-chemical conditions and spatial variation in substrata compositions. Whereas significant differences in population size were noted between seasons for B. anoplus, no differences were found between seasons for density and capture probability for either species. An increase in boulders was associated with increase in population size and density for P. afer; for B. anoplus, increased percentages of bedrock and bank vegetation were associated with an increase in population size and probability of capture, respectively. According to Canonical Correspondence Analysis, size structuring in P. afer was explained predominantly by seasonality, with smaller length classes associated with the seasonal variable of summer, while larger length classes were associated with pH that was higher in winter. By comparison, for B. anoplus, the habitat variables – bank vegetation and bedrock – accounted for much of the explained variance for size structuring. Recruitment appeared to be the major driver of size structuring for the two species; refugia, especially boulders and bank vegetation, also appeared to be important. Overall, the two species were adapted to the headwater streams that were generally variable in environmental conditions. Potential invasions by non-native invasive fishes that occur within the mainstream habitats threaten these two species. Efforts should continue to protect these minnows from such invasions by constructing barriers to upstream migration of non-native fishes into these headwater habitats.
- Full Text:
- Date Issued: 2012
- Authors: Kadye, Wilbert T , Booth, Anthony J
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124866 , vital:35705 , https://doi.10.1111/j.1439-0426.2012.02027.x
- Description: This study examined temporal variation in population dynamics and size structuring of two cyprinid minnows, Pseudobarbus afer and Barbus anoplus, in relation to their proximate physical habitats. Population estimates were determined using three-pass depletion sampling during both summer and winter. The habitats were characterised by seasonal variation in all physico-chemical conditions and spatial variation in substrata compositions. Whereas significant differences in population size were noted between seasons for B. anoplus, no differences were found between seasons for density and capture probability for either species. An increase in boulders was associated with increase in population size and density for P. afer; for B. anoplus, increased percentages of bedrock and bank vegetation were associated with an increase in population size and probability of capture, respectively. According to Canonical Correspondence Analysis, size structuring in P. afer was explained predominantly by seasonality, with smaller length classes associated with the seasonal variable of summer, while larger length classes were associated with pH that was higher in winter. By comparison, for B. anoplus, the habitat variables – bank vegetation and bedrock – accounted for much of the explained variance for size structuring. Recruitment appeared to be the major driver of size structuring for the two species; refugia, especially boulders and bank vegetation, also appeared to be important. Overall, the two species were adapted to the headwater streams that were generally variable in environmental conditions. Potential invasions by non-native invasive fishes that occur within the mainstream habitats threaten these two species. Efforts should continue to protect these minnows from such invasions by constructing barriers to upstream migration of non-native fishes into these headwater habitats.
- Full Text:
- Date Issued: 2012
Life-history characteristics of an age-validated established invasive African sharptooth catfish, Clarias gariepinus, population in a warm–temperate African impoundment
- Wartenberg, Reece, Weyl, Olaf L F, Booth, Anthony J, Winker, A Henning
- Authors: Wartenberg, Reece , Weyl, Olaf L F , Booth, Anthony J , Winker, A Henning
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124921 , vital:35710 , https://doi.10.3377/004.048.0225
- Description: African sharptooth catfish Clarias gariepinus (Burchell, 1822) is a widely distributed fish that has now invaded water bodies in South America, Eastern Europe, Asia and South Africa (Cambray 2003). In South Africa it is native as far south as the Orange-Vaal river system, but inter-basin water transfer schemes (IBWTs), illegal stocking by anglers and from aquaculture has resulted in the establishment of extralimital populations in almost all river systems (van Rensburg et al. 2011). Within the Eastern Cape Province, C. gariepinus has invaded the Great Fish and Sundays rivers through IBWTs, that connect the Orange River to the Great Fish River and then to the Sundays River system which flows directly into Darlington Dam (Kadye & Booth 2013a) (Fig. 1). Soon after the completion of the IBWTs sharptooth catfish were recorded in Grassridge Dam in 1976 (Laurenson & Hocutt 1985), and later from Darlington Dam in 1981 (Scott et al. 2006). Although Cambray & Jubb (1977) are of the opinion that the species was translocated prior to the IBWT connection, there is now a permanent corridor between the Orange River and its receiving river systems that can facilitate the continued introduction of non-native Orange River fishes and other aquatic biota.
- Full Text:
- Date Issued: 2012
- Authors: Wartenberg, Reece , Weyl, Olaf L F , Booth, Anthony J , Winker, A Henning
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124921 , vital:35710 , https://doi.10.3377/004.048.0225
- Description: African sharptooth catfish Clarias gariepinus (Burchell, 1822) is a widely distributed fish that has now invaded water bodies in South America, Eastern Europe, Asia and South Africa (Cambray 2003). In South Africa it is native as far south as the Orange-Vaal river system, but inter-basin water transfer schemes (IBWTs), illegal stocking by anglers and from aquaculture has resulted in the establishment of extralimital populations in almost all river systems (van Rensburg et al. 2011). Within the Eastern Cape Province, C. gariepinus has invaded the Great Fish and Sundays rivers through IBWTs, that connect the Orange River to the Great Fish River and then to the Sundays River system which flows directly into Darlington Dam (Kadye & Booth 2013a) (Fig. 1). Soon after the completion of the IBWTs sharptooth catfish were recorded in Grassridge Dam in 1976 (Laurenson & Hocutt 1985), and later from Darlington Dam in 1981 (Scott et al. 2006). Although Cambray & Jubb (1977) are of the opinion that the species was translocated prior to the IBWT connection, there is now a permanent corridor between the Orange River and its receiving river systems that can facilitate the continued introduction of non-native Orange River fishes and other aquatic biota.
- Full Text:
- Date Issued: 2012
Living lab methodology as an approach to innovation in ICT4D: The Siyakhula Living Lab experience
- Gumbo, Sibukelo, Thinyane, Hannah, Thinyane, Mamello, Terzoli, Alfredo, Hansen, Susan
- Authors: Gumbo, Sibukelo , Thinyane, Hannah , Thinyane, Mamello , Terzoli, Alfredo , Hansen, Susan
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431302 , vital:72762 , https://www.siyakhulall.com/sites/default/files/ISTAfrica_Paper_ref_18_doc_4809_0.pdf
- Description: Underdevelopment and poverty represent key challenges faced by the modern world, which have attracted the attention of NGOs, civil society, government and multinationals. Various undertakings including the United Nations Millennium Development Goals articulation and the World Summit on Information Society highlight the global commitment towards addressing these problems. The solutions to these problems should be derived out of well-structured innovation systems that take into consideration the grassroot context and concerns. A number of in-novation models have been formulated and utilized effectively in differ-ent industries, and some of these have equally been used effectively in community development contexts. This paper elaborates on the Living Lab methodology and its application in ICT4D contexts, highlighting the effectiveness of this model towards integrating end-users within their problem solving effort. This is discussed through the backdrop of the Siyakhula Living Lab, an ICT4D intervention. The embedding environ-ment for this model, which enables key synergies with other stakehold-ers, is also discussed.
- Full Text:
- Date Issued: 2012
- Authors: Gumbo, Sibukelo , Thinyane, Hannah , Thinyane, Mamello , Terzoli, Alfredo , Hansen, Susan
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431302 , vital:72762 , https://www.siyakhulall.com/sites/default/files/ISTAfrica_Paper_ref_18_doc_4809_0.pdf
- Description: Underdevelopment and poverty represent key challenges faced by the modern world, which have attracted the attention of NGOs, civil society, government and multinationals. Various undertakings including the United Nations Millennium Development Goals articulation and the World Summit on Information Society highlight the global commitment towards addressing these problems. The solutions to these problems should be derived out of well-structured innovation systems that take into consideration the grassroot context and concerns. A number of in-novation models have been formulated and utilized effectively in differ-ent industries, and some of these have equally been used effectively in community development contexts. This paper elaborates on the Living Lab methodology and its application in ICT4D contexts, highlighting the effectiveness of this model towards integrating end-users within their problem solving effort. This is discussed through the backdrop of the Siyakhula Living Lab, an ICT4D intervention. The embedding environ-ment for this model, which enables key synergies with other stakehold-ers, is also discussed.
- Full Text:
- Date Issued: 2012
Pre-concentration of toxic metals using electrospun amino-functionalized nylon-6 nanofibre sorbent
- Darko, Godfrey, Sobola, Abdullahi O, Adewuyi, Sheriff, Okonkwo, J O, Torto, Nelson
- Authors: Darko, Godfrey , Sobola, Abdullahi O , Adewuyi, Sheriff , Okonkwo, J O , Torto, Nelson
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6571 , http://hdl.handle.net/10962/d1004134
- Description: This paper presents a new approach for pre-concentrating toxic metals (As, Cd, Ni and Pb) in aqueous environments using an amino-functionalized electrospun nanofibre sorbent. The sorbent, composed of nanofibres of average diameter 80 ± 10 nm and specific surface area of 58m2 g–1, exhibited fast adsorption kinetics (<20 min) for As, Cd, Ni and Pb. The optimalpHfor the uptake of As, Cd, Ni and Pb were 5.5, 6.0, 6.5 and 11, respectively. The adsorption process best fitted the Freundlich isothermand followed the first-order kinetics. The highest pre-concentration achieved using the sorbent was 41.99 (Ni in treated wastewater). The capacity of the sorbent to pre-concentrate the toxic metals was compared with those of aqua regia and HNO3+H2O2 digestions. The pre-concentration factors achieved for Cd in river water samples can be ranked as aqua regia digestion (0.73) > adsorption (0.34)>HNO3+H2O2 (0.23) digestion.Asimilar trend was observed for Ni in river water as well as Ni andCdin tap water samples. Pb ions in the river water samples were pre-concentrated slightly better using the two digestion methods pre-concentration factors ~22) compared to adsorption method (pre-concentration factor ~21). The use of the electrospun amino-functionalized nanofibre sorbent presentsanefficientand cost-effective alternative for pre-concentration of toxic metals inaqueousenvironments.
- Full Text:
- Date Issued: 2012
- Authors: Darko, Godfrey , Sobola, Abdullahi O , Adewuyi, Sheriff , Okonkwo, J O , Torto, Nelson
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6571 , http://hdl.handle.net/10962/d1004134
- Description: This paper presents a new approach for pre-concentrating toxic metals (As, Cd, Ni and Pb) in aqueous environments using an amino-functionalized electrospun nanofibre sorbent. The sorbent, composed of nanofibres of average diameter 80 ± 10 nm and specific surface area of 58m2 g–1, exhibited fast adsorption kinetics (<20 min) for As, Cd, Ni and Pb. The optimalpHfor the uptake of As, Cd, Ni and Pb were 5.5, 6.0, 6.5 and 11, respectively. The adsorption process best fitted the Freundlich isothermand followed the first-order kinetics. The highest pre-concentration achieved using the sorbent was 41.99 (Ni in treated wastewater). The capacity of the sorbent to pre-concentrate the toxic metals was compared with those of aqua regia and HNO3+H2O2 digestions. The pre-concentration factors achieved for Cd in river water samples can be ranked as aqua regia digestion (0.73) > adsorption (0.34)>HNO3+H2O2 (0.23) digestion.Asimilar trend was observed for Ni in river water as well as Ni andCdin tap water samples. Pb ions in the river water samples were pre-concentrated slightly better using the two digestion methods pre-concentration factors ~22) compared to adsorption method (pre-concentration factor ~21). The use of the electrospun amino-functionalized nanofibre sorbent presentsanefficientand cost-effective alternative for pre-concentration of toxic metals inaqueousenvironments.
- Full Text:
- Date Issued: 2012
Seasonal distribution, breeding season and wing moult in the Splendid Glossy Starling Lamprotornis splendidus
- Authors: Craig, Adrian J F K
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449535 , vital:74828 , https://doi.org/10.2989/00306525.2012.655429
- Description: Seasonal migration by Splendid Glossy Starlings has been confirmed only for Kenya and Zambia. Populations in almost all other countries have been categorised as ‘resident’ by some observers, but ‘nomadic’ is a more accurate description of their status. The breeding season is accurately known for few localities. Estimates for the duration of wing moult ranged from 70–130 d based on small samples. Regional divergences in the timing of wing moult remain open to three possible interpretations: (1) differences between years in the timing of wing moult; (2) differences between sex and/or age classes; and (3) population movements, so that birds from different regions may successively occupy the same areas. The available data are inadequate to resolve these questions.
- Full Text:
- Date Issued: 2012
- Authors: Craig, Adrian J F K
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449535 , vital:74828 , https://doi.org/10.2989/00306525.2012.655429
- Description: Seasonal migration by Splendid Glossy Starlings has been confirmed only for Kenya and Zambia. Populations in almost all other countries have been categorised as ‘resident’ by some observers, but ‘nomadic’ is a more accurate description of their status. The breeding season is accurately known for few localities. Estimates for the duration of wing moult ranged from 70–130 d based on small samples. Regional divergences in the timing of wing moult remain open to three possible interpretations: (1) differences between years in the timing of wing moult; (2) differences between sex and/or age classes; and (3) population movements, so that birds from different regions may successively occupy the same areas. The available data are inadequate to resolve these questions.
- Full Text:
- Date Issued: 2012
The nature and quality of the mathematical connections teachers make:
- Mhlolo, Michael K, Schäfer, Marc, Venkat, Hamsa
- Authors: Mhlolo, Michael K , Schäfer, Marc , Venkat, Hamsa
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140893 , vital:37927 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC120887
- Description: Current reforms in mathematics education emphasise the need for pedagogy because it offers learners opportunities to develop their proficiency with complex high-level cognitive processes. One has always associated the ability to make mathematical connections, together with the teacher's role in teaching them, with deep mathematical understanding. This article examines the nature and quality of the mathematical connections that the teachers' representations of those connections enabled or constrained. The researchers made video recordings of four Grade 11 teachers as they taught a series of five lessons on algebra-related topics. The results showed that the teachers' representations of mathematical connections were either faulty or superficial in most cases. It compromised the learners' opportunities for making meaningful mathematical connections. The researchers concluded by suggesting that helping teachers to build their representation repertoires could increase the effectiveness of their instructional practices.
- Full Text:
- Date Issued: 2012
- Authors: Mhlolo, Michael K , Schäfer, Marc , Venkat, Hamsa
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140893 , vital:37927 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC120887
- Description: Current reforms in mathematics education emphasise the need for pedagogy because it offers learners opportunities to develop their proficiency with complex high-level cognitive processes. One has always associated the ability to make mathematical connections, together with the teacher's role in teaching them, with deep mathematical understanding. This article examines the nature and quality of the mathematical connections that the teachers' representations of those connections enabled or constrained. The researchers made video recordings of four Grade 11 teachers as they taught a series of five lessons on algebra-related topics. The results showed that the teachers' representations of mathematical connections were either faulty or superficial in most cases. It compromised the learners' opportunities for making meaningful mathematical connections. The researchers concluded by suggesting that helping teachers to build their representation repertoires could increase the effectiveness of their instructional practices.
- Full Text:
- Date Issued: 2012
The use of response surface methodology to evaluate the impact of level 2 SUPAC–IR changes on the in vitro release of metronidazole and ranitidine from a fixed-dose combination tablet
- King’ori, Loti D, Walker, Roderick B
- Authors: King’ori, Loti D , Walker, Roderick B
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:6391 , http://hdl.handle.net/10962/d1006313
- Description: The purpose of this study was to evaluate the effect of different levels of disintegrant (croscarmellose sodium, CCS), binder (polyvinylprrolidone K30, PVP–K30), and lubricant (magnesium stearate) on the in vitro release of metronidazole (MTZ) and rantidine (RTD) from a solid oral fixed-dose combination tablet. The excipient levels investigated were Level 2 changes in component and composition described in the Scale-Up and Post Approval Changes for Immediate Release (SUPAC–IR) guidance (1). Batches of tablets (1000 units) were manufactured by wet granulation using a Saral high-shear mixer granulator and a Manesty B3B rotary tablet press. Weight uniformity, friability, and disintegration of all tablets were assessed, and all batches complied with compendial specifications. The amount of drug released (Q) at ten minutes was dependent on the levels of CCS in the formulation, and the effect of PVP–K30 and magnesium stearate was dependent on the levels of CCS. Synergistic interactions between independent variables were observed for the Q10 value for RTD, whereas PVP–K30 and magnesium stearate exhibited an antagonistic effect on the Q10 values for MTZ and RTD. The use of response surface methodology facilitated an investigation into the effect of Level 2 component and composition changes, as described in SUPAC–IR, on the in vitro release of MTZ and RTD from a fixed-dose combination (FDC) solid oral dosage form (SODF).
- Full Text:
- Date Issued: 2012
- Authors: King’ori, Loti D , Walker, Roderick B
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:6391 , http://hdl.handle.net/10962/d1006313
- Description: The purpose of this study was to evaluate the effect of different levels of disintegrant (croscarmellose sodium, CCS), binder (polyvinylprrolidone K30, PVP–K30), and lubricant (magnesium stearate) on the in vitro release of metronidazole (MTZ) and rantidine (RTD) from a solid oral fixed-dose combination tablet. The excipient levels investigated were Level 2 changes in component and composition described in the Scale-Up and Post Approval Changes for Immediate Release (SUPAC–IR) guidance (1). Batches of tablets (1000 units) were manufactured by wet granulation using a Saral high-shear mixer granulator and a Manesty B3B rotary tablet press. Weight uniformity, friability, and disintegration of all tablets were assessed, and all batches complied with compendial specifications. The amount of drug released (Q) at ten minutes was dependent on the levels of CCS in the formulation, and the effect of PVP–K30 and magnesium stearate was dependent on the levels of CCS. Synergistic interactions between independent variables were observed for the Q10 value for RTD, whereas PVP–K30 and magnesium stearate exhibited an antagonistic effect on the Q10 values for MTZ and RTD. The use of response surface methodology facilitated an investigation into the effect of Level 2 component and composition changes, as described in SUPAC–IR, on the in vitro release of MTZ and RTD from a fixed-dose combination (FDC) solid oral dosage form (SODF).
- Full Text:
- Date Issued: 2012
Towards empowering learners in a democratic mathematics classroom: to what extent are teachers' listening orientations conducive to and respectful of learners' thinking?
- Mhlolo, Michael K, Schäfer, Marc
- Authors: Mhlolo, Michael K , Schäfer, Marc
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140882 , vital:37926 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC129235
- Description: In an effort to make education accessible, to 'heal the divisions of the past and establish a society based on democratic values', the South African Department of Education claims that a series of mathematics reforms that has so far been introduced is underpinned by the principles of 'social justice, fundamental human rights and inclusivity'. Critics however argue that the system has remained 'undemocratic' in that those groups of learners who were supposed to be 'healed' continue to underperform and hence be disempowered. In this study, we conceptualised a democratic and mathematically empowering classroom as one that is consistent with the principle of inclusivity and in which a hermeneutic listening orientation towards teaching promotes such a democratic and mathematically empowering learning environment. We then worked with three different orientations teachers might have towards listening in the mathematics classroom: evaluative, interpretive and hermeneutic. We then used these orientations to analyse 20 video-recorded lessons with a specific focus on learners' unexpected contributions and how teachers listened and responded to such contributions. The results were consistent with the literature, which shows that teachers tend to dismiss learners' ways of thinking by imposing their own formalised constructions.
- Full Text:
- Date Issued: 2012
- Authors: Mhlolo, Michael K , Schäfer, Marc
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140882 , vital:37926 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC129235
- Description: In an effort to make education accessible, to 'heal the divisions of the past and establish a society based on democratic values', the South African Department of Education claims that a series of mathematics reforms that has so far been introduced is underpinned by the principles of 'social justice, fundamental human rights and inclusivity'. Critics however argue that the system has remained 'undemocratic' in that those groups of learners who were supposed to be 'healed' continue to underperform and hence be disempowered. In this study, we conceptualised a democratic and mathematically empowering classroom as one that is consistent with the principle of inclusivity and in which a hermeneutic listening orientation towards teaching promotes such a democratic and mathematically empowering learning environment. We then worked with three different orientations teachers might have towards listening in the mathematics classroom: evaluative, interpretive and hermeneutic. We then used these orientations to analyse 20 video-recorded lessons with a specific focus on learners' unexpected contributions and how teachers listened and responded to such contributions. The results were consistent with the literature, which shows that teachers tend to dismiss learners' ways of thinking by imposing their own formalised constructions.
- Full Text:
- Date Issued: 2012