Behaviour and trophic ecology of oceanic triggerfish (Canthidermis maculata) and rainbow runner (Elagatis bipinnulata) associated with floating objects in the open ocean
- Forget, Fabien Rocky Gilbert
- Authors: Forget, Fabien Rocky Gilbert
- Date: 2016
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/193531 , vital:45340
- Description: The oceanic triggerfish (Canthidermis maculata) and rainbow runner (Elagatis bipinnulata) are epipelagic species that commonly associate with floating objects throughout the world’s tropical oceans. Besides tunas, these two species often form the bulk of the aggregation and are major non-target species (bycatch) incidentally captured at fish aggregation devices (FADs) by tropical tuna purse seiners. Despite being abundant, little is known about their basic biology, ecology and associative behavior with floating objects. This thesis aims to address knowledge gaps in their associative behavior and ecology at floating objects and attempts to explore potential bycatch mitigation methods. Acoustic telemetry was used to characterise several aspects of the two species’ behavior at floating objects. Fish were captured and tagged at drifting FADs in the core of the western Indian Ocean tuna fishing grounds. Prolonged remote observations were obtained through satellite linked receivers which provided fine-scale data on the behavior of oceanic triggerfish (n= 46 919 cumulated observation days) and rainbow runner (n= 24 538 cumulated observation days). The two species remained associated with the same floating object for periods extending up to several months. The mean residence time estimated using a survival analysis was 65 days for oceanic triggerfish and 94 days for rainbow runner. A distinct diel pattern in association was observed; the two species were closely associated to the FAD during the night and increased their home range during the day while performing short excursions (oceanic triggerfish mean: 2.0 hours ±1.6 SD; rainbow runner mean: 2.4 hours ±2.2 SD) away from the FAD. Similarly, distinct patterns in the vertical movements and locomotory activity (measured using accelerometer tags) were observed as the two species increased their vertical movements and activity levels during the day. Generally, their vertical movements were largely restricted to the mixed layer (< 60 m). At night, the two species remained close to the surface (0-5 m) where they appear to be in a resting state. An interesting behavioural switch in activity levels and vertical distribution was observed for oceanic triggerfish which coincided with a change in the environment as the FAD drifted close to a cold-core cyclonic eddy. Ambient light appears to be the key stimulus triggering the observed diel behavioural patterns. species-specific vulnerability for target species, skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares), bigeye tuna (Thunnus obesus) and non-target species, including silky shark (Carcharhinus falciformis), oceanic triggerfish, and rainbow runner, to the purse seine fishing gear were investigated. Hourly presence rates at FADs over 24 hours were examined to assess whether the capture rate of non-target species could be reduced at specific times during the day. Silky sharks displayed a similar associative pattern to that of targeted tunas. Moreover, the vulnerability of both target and non-target species were close to the maximum during the period of behavioural transitions at sunrise when the majority of the fishing sets are made. As such, a change in set time in the western Indian Ocean does not appear to be a feasible method to reduce capture rates of non-target species. Stomach content and stable isotope analysis were conducted on oceanic triggerfish (stomach n = 152, isotope n = 65) and rainbow runner (stomach n = 156, isotope n = 71) incidentally captured individuals at FADs by purse seiners. Typical FAD-associated prey items represented a minor component of their diet as they predominantly foraged on zooplankton and micronekton in the water column, suggesting that oceanic triggerfish and rainbow runner do not associate to floating objects for direct trophic advantages. Overlap in their dietary and isotopic niches indicates an intermediate level of competition. Overall, the spatial and trophic ecology of both species are remarkably similar and prolonged associations with FADs indicates that floating objects play a significant ecological role in the pelagic environment for the two species. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2016
- Full Text:
- Date Issued: 2016
- Authors: Forget, Fabien Rocky Gilbert
- Date: 2016
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/193531 , vital:45340
- Description: The oceanic triggerfish (Canthidermis maculata) and rainbow runner (Elagatis bipinnulata) are epipelagic species that commonly associate with floating objects throughout the world’s tropical oceans. Besides tunas, these two species often form the bulk of the aggregation and are major non-target species (bycatch) incidentally captured at fish aggregation devices (FADs) by tropical tuna purse seiners. Despite being abundant, little is known about their basic biology, ecology and associative behavior with floating objects. This thesis aims to address knowledge gaps in their associative behavior and ecology at floating objects and attempts to explore potential bycatch mitigation methods. Acoustic telemetry was used to characterise several aspects of the two species’ behavior at floating objects. Fish were captured and tagged at drifting FADs in the core of the western Indian Ocean tuna fishing grounds. Prolonged remote observations were obtained through satellite linked receivers which provided fine-scale data on the behavior of oceanic triggerfish (n= 46 919 cumulated observation days) and rainbow runner (n= 24 538 cumulated observation days). The two species remained associated with the same floating object for periods extending up to several months. The mean residence time estimated using a survival analysis was 65 days for oceanic triggerfish and 94 days for rainbow runner. A distinct diel pattern in association was observed; the two species were closely associated to the FAD during the night and increased their home range during the day while performing short excursions (oceanic triggerfish mean: 2.0 hours ±1.6 SD; rainbow runner mean: 2.4 hours ±2.2 SD) away from the FAD. Similarly, distinct patterns in the vertical movements and locomotory activity (measured using accelerometer tags) were observed as the two species increased their vertical movements and activity levels during the day. Generally, their vertical movements were largely restricted to the mixed layer (< 60 m). At night, the two species remained close to the surface (0-5 m) where they appear to be in a resting state. An interesting behavioural switch in activity levels and vertical distribution was observed for oceanic triggerfish which coincided with a change in the environment as the FAD drifted close to a cold-core cyclonic eddy. Ambient light appears to be the key stimulus triggering the observed diel behavioural patterns. species-specific vulnerability for target species, skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares), bigeye tuna (Thunnus obesus) and non-target species, including silky shark (Carcharhinus falciformis), oceanic triggerfish, and rainbow runner, to the purse seine fishing gear were investigated. Hourly presence rates at FADs over 24 hours were examined to assess whether the capture rate of non-target species could be reduced at specific times during the day. Silky sharks displayed a similar associative pattern to that of targeted tunas. Moreover, the vulnerability of both target and non-target species were close to the maximum during the period of behavioural transitions at sunrise when the majority of the fishing sets are made. As such, a change in set time in the western Indian Ocean does not appear to be a feasible method to reduce capture rates of non-target species. Stomach content and stable isotope analysis were conducted on oceanic triggerfish (stomach n = 152, isotope n = 65) and rainbow runner (stomach n = 156, isotope n = 71) incidentally captured individuals at FADs by purse seiners. Typical FAD-associated prey items represented a minor component of their diet as they predominantly foraged on zooplankton and micronekton in the water column, suggesting that oceanic triggerfish and rainbow runner do not associate to floating objects for direct trophic advantages. Overlap in their dietary and isotopic niches indicates an intermediate level of competition. Overall, the spatial and trophic ecology of both species are remarkably similar and prolonged associations with FADs indicates that floating objects play a significant ecological role in the pelagic environment for the two species. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2016
- Full Text:
- Date Issued: 2016
Binding and entry of a non-enveloped T=4 insect RNA virus is triggered by alkaline pH
- Penkler, David L, Jiwaji, Meesbah, Domitrovic, Tatiana, Short, James R, Johnson, John E, Dorrington, Rosemary A
- Authors: Penkler, David L , Jiwaji, Meesbah , Domitrovic, Tatiana , Short, James R , Johnson, John E , Dorrington, Rosemary A
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65995 , vital:28875 , https://doi.org/10.1016/j.virol.2016.08.028
- Description: publisher version , Tetraviruses are small, non-enveloped, RNA viruses that exclusively infect lepidopteran insects. Their particles comprise 240 copies of a single capsid protein precursor (CP), which undergoes autoproteolytic cleavage during maturation. The molecular mechanisms of capsid assembly and maturation are well understood, but little is known about the viral infectious lifecycle due to a lack of tissue culture cell lines that are susceptible to tetravirus infection. We show here that binding and entry of the alphatetravirus, Helicoverpa armigera stunt virus (HaSV), is triggered by alkaline pH. At pH 9.0, wild-type HaSV virus particles undergo conformational changes that induce membrane-lytic activity and binding to Spodoptera frugiperda Sf9 cells. Binding is followed by entry and infection, with virus replication complexes detected by immunofluorescence microscopy within 2 h post-infection and the CP after 12 h. HaSV particles produced in S. frugiperda Sf9 cells are infectious. Helicoverpa armigera larval virus biofeed assays showed that pre-treatment with the V-ATPase inhibitor, Bafilomycin A1, resulted in a 50% decrease in larval mortality and stunting, while incubation of virus particles at pH 9.0 prior to infection restored infectivity. Together, these data show that HaSV, and likely other tetraviruses, requires the alkaline environment of the lepidopteran larval midgut for binding and entry into host cells.
- Full Text: false
- Date Issued: 2016
- Authors: Penkler, David L , Jiwaji, Meesbah , Domitrovic, Tatiana , Short, James R , Johnson, John E , Dorrington, Rosemary A
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65995 , vital:28875 , https://doi.org/10.1016/j.virol.2016.08.028
- Description: publisher version , Tetraviruses are small, non-enveloped, RNA viruses that exclusively infect lepidopteran insects. Their particles comprise 240 copies of a single capsid protein precursor (CP), which undergoes autoproteolytic cleavage during maturation. The molecular mechanisms of capsid assembly and maturation are well understood, but little is known about the viral infectious lifecycle due to a lack of tissue culture cell lines that are susceptible to tetravirus infection. We show here that binding and entry of the alphatetravirus, Helicoverpa armigera stunt virus (HaSV), is triggered by alkaline pH. At pH 9.0, wild-type HaSV virus particles undergo conformational changes that induce membrane-lytic activity and binding to Spodoptera frugiperda Sf9 cells. Binding is followed by entry and infection, with virus replication complexes detected by immunofluorescence microscopy within 2 h post-infection and the CP after 12 h. HaSV particles produced in S. frugiperda Sf9 cells are infectious. Helicoverpa armigera larval virus biofeed assays showed that pre-treatment with the V-ATPase inhibitor, Bafilomycin A1, resulted in a 50% decrease in larval mortality and stunting, while incubation of virus particles at pH 9.0 prior to infection restored infectivity. Together, these data show that HaSV, and likely other tetraviruses, requires the alkaline environment of the lepidopteran larval midgut for binding and entry into host cells.
- Full Text: false
- Date Issued: 2016
Bioinformatic characterization of type-specific sequence and structural features in auxiliary activity family 9 proteins:
- Moses, Vuyani, Hatherley, Rowan, Tastan Bishop, Özlem
- Authors: Moses, Vuyani , Hatherley, Rowan , Tastan Bishop, Özlem
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148358 , vital:38732 , DOI: 10.1186/s13068-016-0655-2
- Description: Due to the impending depletion of fossil fuels, it has become important to identify alternative energy sources. The biofuel industry has proven to be a promising alternative. However, owing to the complex nature of plant biomass, hence the degradation, biofuel production remains a challenge. The copper-dependent Auxiliary Activity family 9 (AA9) proteins have been found to act synergistically with other cellulose-degrading enzymes resulting in an increased rate of cellulose breakdown. AA9 proteins are lytic polysaccharide monooxygenase (LPMO) enzymes, otherwise known as polysaccharide monooxygenases (PMOs). They are further classified as Type 1, 2 or 3 PMOs, depending on the different cleavage products formed. As AA9 proteins are known to exhibit low sequence conservation, the analysis of unique features of AA9 domains of these enzymes should provide insights for the better understanding of how different AA9 PMO types function.
- Full Text:
- Date Issued: 2016
- Authors: Moses, Vuyani , Hatherley, Rowan , Tastan Bishop, Özlem
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148358 , vital:38732 , DOI: 10.1186/s13068-016-0655-2
- Description: Due to the impending depletion of fossil fuels, it has become important to identify alternative energy sources. The biofuel industry has proven to be a promising alternative. However, owing to the complex nature of plant biomass, hence the degradation, biofuel production remains a challenge. The copper-dependent Auxiliary Activity family 9 (AA9) proteins have been found to act synergistically with other cellulose-degrading enzymes resulting in an increased rate of cellulose breakdown. AA9 proteins are lytic polysaccharide monooxygenase (LPMO) enzymes, otherwise known as polysaccharide monooxygenases (PMOs). They are further classified as Type 1, 2 or 3 PMOs, depending on the different cleavage products formed. As AA9 proteins are known to exhibit low sequence conservation, the analysis of unique features of AA9 domains of these enzymes should provide insights for the better understanding of how different AA9 PMO types function.
- Full Text:
- Date Issued: 2016
Biological activity of extracellular and intracellular polysaccharides from Pleurotus tuber-regium hybrid and mutant strains
- Bamigboye, Comfort O, Oloke, Julius K, Dames, Joanna Felicity
- Authors: Bamigboye, Comfort O , Oloke, Julius K , Dames, Joanna Felicity
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69056 , vital:29376 , http://pubs.sciepub.com/jfnr/4/7/2/
- Description: Publisher version , Pleurotus tuber-regium (Fr.) Singer (1951) is a unique sclerotium-forming edible and medicinal mushroom. Interestingly, both the sclerotium and mushroom are edible and are often used for curing various ailments. Previous studies have focused on the antimicrobial and antioxidant activity of the extracellular polysaccharide (EPS) from wild P. tuber-regium. There has been no report on the intracellular polysaccharide (IPS) of the wild mycelia, likewise there is very meager information on the improvement of the perceived potentials of P. tuber-regium. This research study analysed the EPS and IPS fractions of P. tuber-regium hybrid and mutant strains. The antimicrobial potential of the IPS and EPS fractions, their scavenging activity on 1, 1-diphenyl–2picryhydrazyl (DPPH) and Hydroxyl radicals were also determined. Both IPS and EPS fractions of P. tuber-regium hybrids and mutants showed increased DPPH and hydroxyl scavenging activity over the wild P. tuber-regium with an EC50 mostly 1 mg/ml. The antimicrobial activity of the IPS from a mutant strain had an IC50 of 15.6 mg/ml compared to the wild type (18.75 mg /ml). This study showed that selected mutant and hybrids of P. tuber-regium had increased radical scavenging activity indicating potentially increased biological activity that could offer increased benefit as a neutraceutical.
- Full Text: false
- Date Issued: 2016
- Authors: Bamigboye, Comfort O , Oloke, Julius K , Dames, Joanna Felicity
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69056 , vital:29376 , http://pubs.sciepub.com/jfnr/4/7/2/
- Description: Publisher version , Pleurotus tuber-regium (Fr.) Singer (1951) is a unique sclerotium-forming edible and medicinal mushroom. Interestingly, both the sclerotium and mushroom are edible and are often used for curing various ailments. Previous studies have focused on the antimicrobial and antioxidant activity of the extracellular polysaccharide (EPS) from wild P. tuber-regium. There has been no report on the intracellular polysaccharide (IPS) of the wild mycelia, likewise there is very meager information on the improvement of the perceived potentials of P. tuber-regium. This research study analysed the EPS and IPS fractions of P. tuber-regium hybrid and mutant strains. The antimicrobial potential of the IPS and EPS fractions, their scavenging activity on 1, 1-diphenyl–2picryhydrazyl (DPPH) and Hydroxyl radicals were also determined. Both IPS and EPS fractions of P. tuber-regium hybrids and mutants showed increased DPPH and hydroxyl scavenging activity over the wild P. tuber-regium with an EC50 mostly 1 mg/ml. The antimicrobial activity of the IPS from a mutant strain had an IC50 of 15.6 mg/ml compared to the wild type (18.75 mg /ml). This study showed that selected mutant and hybrids of P. tuber-regium had increased radical scavenging activity indicating potentially increased biological activity that could offer increased benefit as a neutraceutical.
- Full Text: false
- Date Issued: 2016
Building capacity for green, just and sustainable futures – a new knowledge field requiring transformative research methodology
- Rosenberg, Eureta, Ramsarup, Presha, Gumede, Sibusisiwe, Lotz-Sisitka, Heila
- Authors: Rosenberg, Eureta , Ramsarup, Presha , Gumede, Sibusisiwe , Lotz-Sisitka, Heila
- Date: 2016
- Subjects: Sustainable development -- South Africa , Renewable energy sources , Climatic changes , Clean energy
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59613 , vital:27631 , http://joe.ukzn.ac.za/Libraries/No_65_2016/JoE_complete.sflb.ashx
- Description: Education has contributed to a society-wide awareness of environmental issues, and we are increasingly confronted with the need for new ways to generate energy, save water and reduce pollution. Thus new forms of work are emerging and government, employers and educators need to know what ‘green’ skills South Africa needs and has. This creates a new demand for ‘green skills’ research. We propose that this new knowledge field – like some other educational fields – requires a transformative approach to research methodology. In conducting reviews of existing research, we found that a transformative approach requires a reframing of key concepts commonly used in researching work and learning; multi-layered, mixed method studies; researching within and across diverse knowledge fields including non-traditional fields; and both newly configured national platforms and new conceptual frameworks to help us integrate coherently across these. Critical realism is presented as a helpful underpinning for such conceptual frameworks, and implications for how universities prepare educational researchers are flagged.
- Full Text:
- Date Issued: 2016
- Authors: Rosenberg, Eureta , Ramsarup, Presha , Gumede, Sibusisiwe , Lotz-Sisitka, Heila
- Date: 2016
- Subjects: Sustainable development -- South Africa , Renewable energy sources , Climatic changes , Clean energy
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59613 , vital:27631 , http://joe.ukzn.ac.za/Libraries/No_65_2016/JoE_complete.sflb.ashx
- Description: Education has contributed to a society-wide awareness of environmental issues, and we are increasingly confronted with the need for new ways to generate energy, save water and reduce pollution. Thus new forms of work are emerging and government, employers and educators need to know what ‘green’ skills South Africa needs and has. This creates a new demand for ‘green skills’ research. We propose that this new knowledge field – like some other educational fields – requires a transformative approach to research methodology. In conducting reviews of existing research, we found that a transformative approach requires a reframing of key concepts commonly used in researching work and learning; multi-layered, mixed method studies; researching within and across diverse knowledge fields including non-traditional fields; and both newly configured national platforms and new conceptual frameworks to help us integrate coherently across these. Critical realism is presented as a helpful underpinning for such conceptual frameworks, and implications for how universities prepare educational researchers are flagged.
- Full Text:
- Date Issued: 2016
Can local use assist in controlling invasive alien species in tropical forests?: The case of Lantana camara in southern India
- Kannan, Ramesh, Shackleton, Charlie M, Krishnan, Smitha, Shaanker, Ramanan U
- Authors: Kannan, Ramesh , Shackleton, Charlie M , Krishnan, Smitha , Shaanker, Ramanan U
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180423 , vital:43387 , xlink:href="https://doi.org/10.1016/j.foreco.2016.06.016"
- Description: Many invasive alien species (IAS) are used by local communities for a variety of subsistence and income generating purposes. This frequently poses a conflict of interest for their removal due to forest conservation and biodiversity concerns. However, if local use can simultaneously check or control specific IAS, the conflict can be avoided and both development and forest conservation perspectives accommodated in the short to medium term. We examine this for Lantana camara invasion in southern India through assessment of the demand for and impacts of harvesting on this globally problematic IAS. We interviewed local artisans regarding their knowledge and quantities of Lantana used, along with forest surveys to estimate Lantana densities and size classes in harvested and unharvested sites, and lastly we undertook controlled cutting in moist and dry deciduous forests in both the wet and dry seasons to examine rate of regrowth and mortality. Over the entire study area the abundance of Lantana far outweighed local demand, but at small scales around villages, density and size classes were significantly reduced through harvesting. The controlled cutting experiment showed marked seasonal differences, with the most severe cutting intensity resulting in significant mortality when Lantana plants were cut in the wet season, but with limited effect when cut in the dry season. We conclude that promoting local use of IAS may be a feasible approach in controlling them and thereby limiting their impacts in forests.
- Full Text:
- Date Issued: 2016
- Authors: Kannan, Ramesh , Shackleton, Charlie M , Krishnan, Smitha , Shaanker, Ramanan U
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180423 , vital:43387 , xlink:href="https://doi.org/10.1016/j.foreco.2016.06.016"
- Description: Many invasive alien species (IAS) are used by local communities for a variety of subsistence and income generating purposes. This frequently poses a conflict of interest for their removal due to forest conservation and biodiversity concerns. However, if local use can simultaneously check or control specific IAS, the conflict can be avoided and both development and forest conservation perspectives accommodated in the short to medium term. We examine this for Lantana camara invasion in southern India through assessment of the demand for and impacts of harvesting on this globally problematic IAS. We interviewed local artisans regarding their knowledge and quantities of Lantana used, along with forest surveys to estimate Lantana densities and size classes in harvested and unharvested sites, and lastly we undertook controlled cutting in moist and dry deciduous forests in both the wet and dry seasons to examine rate of regrowth and mortality. Over the entire study area the abundance of Lantana far outweighed local demand, but at small scales around villages, density and size classes were significantly reduced through harvesting. The controlled cutting experiment showed marked seasonal differences, with the most severe cutting intensity resulting in significant mortality when Lantana plants were cut in the wet season, but with limited effect when cut in the dry season. We conclude that promoting local use of IAS may be a feasible approach in controlling them and thereby limiting their impacts in forests.
- Full Text:
- Date Issued: 2016
Case Studies for UNECCC, UNESCO and CEE The COPART Climate Train
- Authors: McGarry, Dylan K
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391120 , vital:68622 , xlink:href="https://eeasa.org.za/wp-content/uploads/2017/05/EEASA-Bullitin-2016_18-July-issue-42.pdf"
- Description: To create a listening and educational platform that used various disciplines to understand the impact of Climate Change across South Africa. The objective was to create a multigenre educational space for citizens of South Africa as a means to participate in Climate discussions as an alternative to the COP17 negotiations held in South Africa at the time.
- Full Text:
- Date Issued: 2016
- Authors: McGarry, Dylan K
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391120 , vital:68622 , xlink:href="https://eeasa.org.za/wp-content/uploads/2017/05/EEASA-Bullitin-2016_18-July-issue-42.pdf"
- Description: To create a listening and educational platform that used various disciplines to understand the impact of Climate Change across South Africa. The objective was to create a multigenre educational space for citizens of South Africa as a means to participate in Climate discussions as an alternative to the COP17 negotiations held in South Africa at the time.
- Full Text:
- Date Issued: 2016
Changing practices, changing values?: a Bernsteinian analysis of knowledge production and knowledge exchange in two UK universities
- Little, Brenda, Abbas, Andrea, Singh, Mala
- Authors: Little, Brenda , Abbas, Andrea , Singh, Mala
- Date: 2016
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/66934 , vital:29002 , https://doi.org/10.1007/978-94-017-7369-0_8
- Description: publisher version , Bernstein’s concept of classification and framing links notions of knowledge, democracy and social justice, providing a perspective from which to address critical questions of what knowledge is produced, who has access to it, and how knowledge is distributed. Bernstein’s conceptual framework is used to inform an analysis of national policies steering knowledge production and knowledge transfer in the UK, and the changing practices and values associated with knowledge production and knowledge transfer in two UK institutional case study universities. The analysis reveals how reputational and financial consequences of the formal assessment of research quality interacts with the institutional and disciplinary contexts of research units to differently shape what knowledge is valued and produced, and with whom it is shared. Five discursive areas, each involving a complex set of classifications (power) and framings (control) are identified, namely: the national research assessment framework; the economic value of research; discourses of social and academic values; academic freedoms; and mixed-discipline research and the interdisciplinary nature of real world problems. Though competing and sometimes contradictory values seem to underlie academics’ knowledge work, it seems that the strong framing for knowledge production and knowledge exchange provided by national policies steers staff efforts towards economised codes of knowledge. The conclusion suggests that such a strong steer does not value social transformation in all its diverse non-economistic dimensions and limits universities’ potential to transform societies to further social justice.
- Full Text: false
- Date Issued: 2016
- Authors: Little, Brenda , Abbas, Andrea , Singh, Mala
- Date: 2016
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/66934 , vital:29002 , https://doi.org/10.1007/978-94-017-7369-0_8
- Description: publisher version , Bernstein’s concept of classification and framing links notions of knowledge, democracy and social justice, providing a perspective from which to address critical questions of what knowledge is produced, who has access to it, and how knowledge is distributed. Bernstein’s conceptual framework is used to inform an analysis of national policies steering knowledge production and knowledge transfer in the UK, and the changing practices and values associated with knowledge production and knowledge transfer in two UK institutional case study universities. The analysis reveals how reputational and financial consequences of the formal assessment of research quality interacts with the institutional and disciplinary contexts of research units to differently shape what knowledge is valued and produced, and with whom it is shared. Five discursive areas, each involving a complex set of classifications (power) and framings (control) are identified, namely: the national research assessment framework; the economic value of research; discourses of social and academic values; academic freedoms; and mixed-discipline research and the interdisciplinary nature of real world problems. Though competing and sometimes contradictory values seem to underlie academics’ knowledge work, it seems that the strong framing for knowledge production and knowledge exchange provided by national policies steers staff efforts towards economised codes of knowledge. The conclusion suggests that such a strong steer does not value social transformation in all its diverse non-economistic dimensions and limits universities’ potential to transform societies to further social justice.
- Full Text: false
- Date Issued: 2016
Characterization and Analysis of NTP Amplifier Traffic
- Rudman, Lauren, Irwin, Barry V W
- Authors: Rudman, Lauren , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429482 , vital:72616 , 10.23919/SAIEE.2016.8531542
- Description: Network Time Protocol based DDoS attacks saw a lot of popularity throughout 2014. This paper shows the characterization and analysis of two large datasets containing packets from NTP based DDoS attacks captured in South Africa. Using a series of Python based tools, the dataset is analysed according to specific parts of the packet headers. These include the source IP address and Time-to-Live (TTL) values. The analysis found the top source addresses and looked at the TTL values observed for each address. These TTL values can be used to calculate the probable operating system or DDoS attack tool used by an attacker. We found that each TTL value seen for an address can indicate the number of hosts attacking the address or indicate minor routing changes. The Time-to-Live values are then analysed as a whole to find the total number used throughout each attack. The most frequent TTL values are then found and show that the majority of them indicate the attackers are using an initial TTL of 255. This value can indicate the use of a certain DDoS tool that creates packets with that exact initial TTL. The TTL values are then put into groups that can show the number of IP addresses a group of hosts are targeting. The paper discusses our work with two brief case studies correlating observed data to real-world attacks, and the observable impact thereof.
- Full Text:
- Date Issued: 2016
- Authors: Rudman, Lauren , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429482 , vital:72616 , 10.23919/SAIEE.2016.8531542
- Description: Network Time Protocol based DDoS attacks saw a lot of popularity throughout 2014. This paper shows the characterization and analysis of two large datasets containing packets from NTP based DDoS attacks captured in South Africa. Using a series of Python based tools, the dataset is analysed according to specific parts of the packet headers. These include the source IP address and Time-to-Live (TTL) values. The analysis found the top source addresses and looked at the TTL values observed for each address. These TTL values can be used to calculate the probable operating system or DDoS attack tool used by an attacker. We found that each TTL value seen for an address can indicate the number of hosts attacking the address or indicate minor routing changes. The Time-to-Live values are then analysed as a whole to find the total number used throughout each attack. The most frequent TTL values are then found and show that the majority of them indicate the attackers are using an initial TTL of 255. This value can indicate the use of a certain DDoS tool that creates packets with that exact initial TTL. The TTL values are then put into groups that can show the number of IP addresses a group of hosts are targeting. The paper discusses our work with two brief case studies correlating observed data to real-world attacks, and the observable impact thereof.
- Full Text:
- Date Issued: 2016
Characterization and Electrocatalytic Activity of Nanocomposites Consisting of Nanosized Cobalt Tetraaminophenoxy Phthalocyanine, Multi‐walled Carbon Nanotubes and Gold Nanoparticles
- Shumba, Munyaradzi, Nyokong, Tebello
- Authors: Shumba, Munyaradzi , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188659 , vital:44773 , xlink:href="https://doi.org/10.1002/elan.201501058"
- Description: Glassy carbon electrodes were modified with composites containing cobalt tetraaminophenoxy phthalocyanine nanoparticles (CoTAPhPcNP), multi-walled carbon nanotubes (MWCNT) and gold nanorods (AuNRs). The modified electrodes were studied for their electrocatalytic behavior towards the reduction of hydrogen peroxide. Phthalocyanine nanoparticles significantly improved electron transfer kinetics as compared to phthalocyanines which are not in the nanoparticle form when alone or in the presence of multiwalled carbon nanotubes (MWCNTs). CoTAPhPcNP-MWCNT-GCE proved to be suitable for hydrogen peroxide detection with a catalytic rate constant of 3.45×103 M−1 s−1 and a detection limit of 1.61×10−7 M. Adsorption Gibbs free energy ΔGo was found to be −19.22 kJ mol−1 for CoTAPhPcNP-MWCNT-GCE.
- Full Text:
- Date Issued: 2016
- Authors: Shumba, Munyaradzi , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188659 , vital:44773 , xlink:href="https://doi.org/10.1002/elan.201501058"
- Description: Glassy carbon electrodes were modified with composites containing cobalt tetraaminophenoxy phthalocyanine nanoparticles (CoTAPhPcNP), multi-walled carbon nanotubes (MWCNT) and gold nanorods (AuNRs). The modified electrodes were studied for their electrocatalytic behavior towards the reduction of hydrogen peroxide. Phthalocyanine nanoparticles significantly improved electron transfer kinetics as compared to phthalocyanines which are not in the nanoparticle form when alone or in the presence of multiwalled carbon nanotubes (MWCNTs). CoTAPhPcNP-MWCNT-GCE proved to be suitable for hydrogen peroxide detection with a catalytic rate constant of 3.45×103 M−1 s−1 and a detection limit of 1.61×10−7 M. Adsorption Gibbs free energy ΔGo was found to be −19.22 kJ mol−1 for CoTAPhPcNP-MWCNT-GCE.
- Full Text:
- Date Issued: 2016
Citizen Monitoring of The National Water Resource Strategy 2 (NWRS2)
- Wilson, Jessica, Munnik, Victor, Burt, Jane C, Pereira, Taryn, Ngcozela, Thabang, Mokoena, Samson, Lusithi, Thabo, Lotz-Sisitka, Heila, Ndhlovu, December, Ngcanga, Thandiwe, Tshabalala, Mduduzi, James, Manelisi, Mashile, Alexander, Mdululi, Patricia
- Authors: Wilson, Jessica , Munnik, Victor , Burt, Jane C , Pereira, Taryn , Ngcozela, Thabang , Mokoena, Samson , Lusithi, Thabo , Lotz-Sisitka, Heila , Ndhlovu, December , Ngcanga, Thandiwe , Tshabalala, Mduduzi , James, Manelisi , Mashile, Alexander , Mdululi, Patricia
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/436812 , vital:73307 , ISBN 978-1-4312-0922-4 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2313%20_final.pdf
- Description: In 2014, the South African Water Caucus (SAWC), a network of non-governmental organisations (NGOs) and community-based organisations (CBOs) who are active in the water sec-tor, embarked on a social learning and action research journey supported by the South African Water Research Commission (WRC) to deepen its monitoring of South Africa’s Second Na-tional Water Resources Strategy (NWRS2). They focused on three issues in three cases study areas.
- Full Text:
- Date Issued: 2016
- Authors: Wilson, Jessica , Munnik, Victor , Burt, Jane C , Pereira, Taryn , Ngcozela, Thabang , Mokoena, Samson , Lusithi, Thabo , Lotz-Sisitka, Heila , Ndhlovu, December , Ngcanga, Thandiwe , Tshabalala, Mduduzi , James, Manelisi , Mashile, Alexander , Mdululi, Patricia
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/436812 , vital:73307 , ISBN 978-1-4312-0922-4 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2313%20_final.pdf
- Description: In 2014, the South African Water Caucus (SAWC), a network of non-governmental organisations (NGOs) and community-based organisations (CBOs) who are active in the water sec-tor, embarked on a social learning and action research journey supported by the South African Water Research Commission (WRC) to deepen its monitoring of South Africa’s Second Na-tional Water Resources Strategy (NWRS2). They focused on three issues in three cases study areas.
- Full Text:
- Date Issued: 2016
Citizen Monitoring of the NWRS2. WRC report 2313
- Wilson, Jessica, Munnik, Victor, Burt, Jane C, Pereira, Taryn, Ngcozela, Thabang, Lusithi, Thabo, Lotz-Sisitka, Heila
- Authors: Wilson, Jessica , Munnik, Victor , Burt, Jane C , Pereira, Taryn , Ngcozela, Thabang , Lusithi, Thabo , Lotz-Sisitka, Heila
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432979 , vital:72920 , xlink:href="https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2313%20_final.pdf"
- Description: In 2014, the South African Water Caucus (SAWC), a network of non-governmental organisations (NGOs) and community-based organisations (CBOs) who are active in the water sector, embarked on a social learning and action research journey supported by the South African Water Research Commission (WRC) to deepen its monitoring of South Africa’s Second National Water Resources Strategy (NWRS2). They focused on three issues in three cases study areas.
- Full Text:
- Date Issued: 2016
- Authors: Wilson, Jessica , Munnik, Victor , Burt, Jane C , Pereira, Taryn , Ngcozela, Thabang , Lusithi, Thabo , Lotz-Sisitka, Heila
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432979 , vital:72920 , xlink:href="https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2313%20_final.pdf"
- Description: In 2014, the South African Water Caucus (SAWC), a network of non-governmental organisations (NGOs) and community-based organisations (CBOs) who are active in the water sector, embarked on a social learning and action research journey supported by the South African Water Research Commission (WRC) to deepen its monitoring of South Africa’s Second National Water Resources Strategy (NWRS2). They focused on three issues in three cases study areas.
- Full Text:
- Date Issued: 2016
Co-designing research on transgressive learning in times of climate change
- Lotz-Sisitka, Heila, Ali, Million B, Mphepho, Gibson, Chaves, Martha, Macintyre, Thomas, Pesanayi, Tichaona V, Wals, Arjen E, Mukute, Mutizwa, Kronlid, David O, Tran, Duc, Joon, Deepika, McGarry, Dylan K
- Authors: Lotz-Sisitka, Heila , Ali, Million B , Mphepho, Gibson , Chaves, Martha , Macintyre, Thomas , Pesanayi, Tichaona V , Wals, Arjen E , Mukute, Mutizwa , Kronlid, David O , Tran, Duc , Joon, Deepika , McGarry, Dylan K
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182472 , vital:43833 , xlink:href="https://doi.org/10.1016/j.cosust.2016.04.004"
- Description: This paper reflects on the epistemological context for the co-design of a research programme on transformative, transgressive learning emerging at the nexus of climate change, water and food security, energy and social justice. It outlines a sequence of learning actions that we, as a group of collaborating partners in a Transformative Knowledge Network (TKN) undertook to co-design a research programme, firstly in situ in various case study contexts, and secondly together across case study contexts. Finally, it provides some reflections and learning points.
- Full Text:
- Date Issued: 2016
- Authors: Lotz-Sisitka, Heila , Ali, Million B , Mphepho, Gibson , Chaves, Martha , Macintyre, Thomas , Pesanayi, Tichaona V , Wals, Arjen E , Mukute, Mutizwa , Kronlid, David O , Tran, Duc , Joon, Deepika , McGarry, Dylan K
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182472 , vital:43833 , xlink:href="https://doi.org/10.1016/j.cosust.2016.04.004"
- Description: This paper reflects on the epistemological context for the co-design of a research programme on transformative, transgressive learning emerging at the nexus of climate change, water and food security, energy and social justice. It outlines a sequence of learning actions that we, as a group of collaborating partners in a Transformative Knowledge Network (TKN) undertook to co-design a research programme, firstly in situ in various case study contexts, and secondly together across case study contexts. Finally, it provides some reflections and learning points.
- Full Text:
- Date Issued: 2016
Co-management, land rights, and conflicts around South Africa’s Silaka Nature Reserve
- Thondhlana, Gladman, Cundill, Georgina, Kepe, Thembele
- Authors: Thondhlana, Gladman , Cundill, Georgina , Kepe, Thembele
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67781 , vital:29144 , https://doi.org/10.1080/08941920.2015.1089609
- Description: Publisher version , Globally, co-management of protected areas (PAs) offers promise in efforts to achieve ecological integrity and livelihood needs. Most co-management agreements are premised on joint decision making in defining equitable sharing of benefits from and the management responsibilities for natural resource management. However, co-managed PAs are often conflict ridden. The forceful closure of Silaka Nature Reserve in South Africa in 2013 by a local community epitomizes the conflicts that can emerge in co-management arrangements. Using Silaka Reserve as a case study, we ask questions related to the meaning of land to local people, with an interrogative focus beyond “material benefits” in co-management discourse. The results of this study show that apart from nonaccrual of material benefits, conflicts arise from nonrecognition of nonmaterial aspects such as cultural values of and historical attachment to land and limited involvement of land claimants in decision making. The implications for co-management as a desired outcome on settled land claims are discussed.
- Full Text: false
- Date Issued: 2016
- Authors: Thondhlana, Gladman , Cundill, Georgina , Kepe, Thembele
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67781 , vital:29144 , https://doi.org/10.1080/08941920.2015.1089609
- Description: Publisher version , Globally, co-management of protected areas (PAs) offers promise in efforts to achieve ecological integrity and livelihood needs. Most co-management agreements are premised on joint decision making in defining equitable sharing of benefits from and the management responsibilities for natural resource management. However, co-managed PAs are often conflict ridden. The forceful closure of Silaka Nature Reserve in South Africa in 2013 by a local community epitomizes the conflicts that can emerge in co-management arrangements. Using Silaka Reserve as a case study, we ask questions related to the meaning of land to local people, with an interrogative focus beyond “material benefits” in co-management discourse. The results of this study show that apart from nonaccrual of material benefits, conflicts arise from nonrecognition of nonmaterial aspects such as cultural values of and historical attachment to land and limited involvement of land claimants in decision making. The implications for co-management as a desired outcome on settled land claims are discussed.
- Full Text: false
- Date Issued: 2016
Collaborative learning of water conservation practices: cultivation and expansion of a learning network around rainwater harvesting demonstration sites in the Eastern Cape, South Africa
- Pesanayi, Tichaona V, Weaver, Kim N
- Authors: Pesanayi, Tichaona V , Weaver, Kim N
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/392086 , vital:68720 , xlink:href="https://www.ajol.info/index.php/sajae/article/view/138570"
- Description: Learning together in mediated voluntary networks can mobilise skills and innovations that help to facilitate learning and uptake of rainwater harvesting and conservation practices. It boosts extension capacity while at the same time growing farmer capabilities, tapping on the distributed cognition. These practices help to heal wicked problems of drought and global change challenges affecting marginalised farmers in South Africa. South Africa has water, nutrition and food security challenges, especially the Eastern Cape Province where there is a relatively high level of poverty. These challenges place heavy pressure on the agricultural sector as it is the main user of the allocated water in the country. In this paper, the learning of and agency for rainwater harvesting and conservation practices are explored as responses to these challenges. Despite existing cultural histories of such practices among the amaXhosa people, information on these practices is not readily available to small-scale rural farmers who thus struggle for the want of knowing. This research forms part of a Water Research Commission project, Amanzi for Food, whose intention is to mediate collaborative and co-engaged learning among networked farmers, extension workers, researchers and agricultural educators through course-mediated use of Water Research Commission rainwater harvesting and conservation materials.
- Full Text:
- Date Issued: 2016
- Authors: Pesanayi, Tichaona V , Weaver, Kim N
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/392086 , vital:68720 , xlink:href="https://www.ajol.info/index.php/sajae/article/view/138570"
- Description: Learning together in mediated voluntary networks can mobilise skills and innovations that help to facilitate learning and uptake of rainwater harvesting and conservation practices. It boosts extension capacity while at the same time growing farmer capabilities, tapping on the distributed cognition. These practices help to heal wicked problems of drought and global change challenges affecting marginalised farmers in South Africa. South Africa has water, nutrition and food security challenges, especially the Eastern Cape Province where there is a relatively high level of poverty. These challenges place heavy pressure on the agricultural sector as it is the main user of the allocated water in the country. In this paper, the learning of and agency for rainwater harvesting and conservation practices are explored as responses to these challenges. Despite existing cultural histories of such practices among the amaXhosa people, information on these practices is not readily available to small-scale rural farmers who thus struggle for the want of knowing. This research forms part of a Water Research Commission project, Amanzi for Food, whose intention is to mediate collaborative and co-engaged learning among networked farmers, extension workers, researchers and agricultural educators through course-mediated use of Water Research Commission rainwater harvesting and conservation materials.
- Full Text:
- Date Issued: 2016
Community care worker perceptions of their roles in tuberculosis care and their information needs:
- Okeyo, Ida L A, Dowse, Roslind
- Authors: Okeyo, Ida L A , Dowse, Roslind
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156596 , vital:40029 , DOI: 10.4102/hsag.v21i0.962
- Description: Community care workers (CCWs) inhabit a central role in the management of tuberculosis (TB) patients in South Africa. CCWs attend training courses, but training is not standardised at either the national or provincial level. To explore perceptions of CCWs of their role in TB care and TB information needs.
- Full Text:
- Date Issued: 2016
- Authors: Okeyo, Ida L A , Dowse, Roslind
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156596 , vital:40029 , DOI: 10.4102/hsag.v21i0.962
- Description: Community care workers (CCWs) inhabit a central role in the management of tuberculosis (TB) patients in South Africa. CCWs attend training courses, but training is not standardised at either the national or provincial level. To explore perceptions of CCWs of their role in TB care and TB information needs.
- Full Text:
- Date Issued: 2016
Community structure and trophic ecology of shallow and deep rocky reefs in a well-established marine protected area
- Authors: Heyns, Elodie R
- Date: 2016
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54438 , vital:26565
- Description: The now formally adopted ecosystem approach to fisheries (EAF) considers not only commercially important species, but the entire ecosystem and the processes that support these species. A key component of EAF management is the implementation of no-take Marine Protected Areas (MPAs). Shallow water fish stocks are depleted and fishing effort is moving deeper and further offshore to keep up with demands. This situation calls for a detailed investigation of deep nearshore reefs to provide critical information relevant to policy uptake and management decisions regarding existing and new MPAs in terms of zonation and use. To address this need, the aim of this thesis was to investigate reefs that lie between 45 and 75 m and compare them in terms of community structure and function to the relatively well-studied shallow reefs that lie within SCUBA diving depth (<25 m). Ecological collections were made in the centre of a large and well-established MPA, Tsitsikamma National Park, to ensure that data represented non-anthropogenically impacted communities. Data were collected from two study sites; Rheeders Reef, (shallow reef) and Middlebank, a deep reef complex situated near the Storms River Mouth. The first step to address the aim of this study was to obtain baseline data on the distribution patterns of both the macrobenthic invertebrates and fish assemblages. Baseline data were obtained by underwater video methods and included the use of a remotely operated vehicle, baited remote underwater stereo-video systems (stereo-BRUVs) and traditional underwater camera equipment operated by SCUBA divers. To establish functional differences between the two study sites, fatty acid (FA) and stable isotope (SI) analyses were employed. These biomarker techniques provided insight into the importance of different sources of primary production, nutritional condition and species packing. From 360 photoquadrats examined for macrobenthic invertebrate distribution patterns, 161 invertebrates were identified that demonstrated a clear changeover of species along the depth gradient. Species richness was highest on the shallow reef and decreased with an increase in depth. To understand how the measured environmental variables impacted the macrobenthic assemblage data a LINKTREE analysis was performed. LINKTREEs produce hierarchical cluster analysis based on the macrobenthic assemblage data and provide a threshold of environmental variables that correspond to each cluster. The outcome of the LINKTREE analysis indicated that the changeover of species resulted in four distinct clusters, each cluster associated with a particular set of environmental variables that fell within a depth range. On the shallowest sites, the high energy environment resulting from wave action and surge prevented the settlement of suspended particles. The high energy environment of the shallow reef selected for low-growing encrusting species. High light intensities supported great abundances of benthic algae, and as light was lost with increasing depth, algal cover gradually diminished until it was completely absent on the deep reef. The reduced impact of surface wave action on the deep reef caused increased levels of settled suspended particles. The high levels of settled particles likely caused clogging of feeding parts of the encrusting species. Consequently, upright growth forms were more common in the lower energy environment of the deep reef. A total of 48 fish species were identified from 51 stereo-BRUVs samples. Fish assemblages differed significantly between the shallow and deep reefs. The shallowest sites were characterised by many small and juvenile fish species that fed at lower trophic levels. The deep reef supported the majority of the large predatory fish that fed at higher trophic levels. Many species demonstrated depth-related ontogenetic shifts in habitat use, and as such the deep reef hosted the majority of the sexually mature individuals. The fish assemblages also demonstrated a strong association with the macrobenthic clusters identified as habitat types by the LINKTREE analysis. The results from 201 FA and 191 SI samples provided information on specific feeding interactions, but more importantly shed some light on different processes that supported the shallow and deep reef communities. The shallow reef community was characterised by greater diversity of food sources, a pattern that could be explained by the presence of benthic algae and terrestrial inputs. Greater diversity of carbon sources at the bottom of the food web meant that a larger variety of species could be supported. Higher species richness increased the number of distinct taxa that performed similar functions, rendering the shallow reef more redundant and consequently more resilient to disturbance. In contrast, the deep reef demonstrated a food web supported mainly by pelagic production, which was more variable both over space and time. The deep reef was less redundant when compared to the shallow reef, as fewer species demonstrated similar trophic niches. These factors, in addition to the increased presence of sensitive calcareous macrobenthic species on the deep study site, rendered the deep reef more vulnerable to disturbance when compared to the shallow reef. Although the data presented here were from a single study area, the limitations typically associated with these inaccessible and challenging sampling environments made the dataset a significant contribution to the knowledge of reef ecosystems. The study addressed priority research questions for South Africa as identified during the National Biodiversity Assessment. The observable differences in structure, function and vulnerability point to the need for continued protection of our shallow reefs and offshore expansion of our MPA networks. Future research should determine if the patterns identified here are common throughout the Agulhas Ecoregion to provide managers with robust evidence for the extension our MPAs offshore.
- Full Text:
- Date Issued: 2016
- Authors: Heyns, Elodie R
- Date: 2016
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54438 , vital:26565
- Description: The now formally adopted ecosystem approach to fisheries (EAF) considers not only commercially important species, but the entire ecosystem and the processes that support these species. A key component of EAF management is the implementation of no-take Marine Protected Areas (MPAs). Shallow water fish stocks are depleted and fishing effort is moving deeper and further offshore to keep up with demands. This situation calls for a detailed investigation of deep nearshore reefs to provide critical information relevant to policy uptake and management decisions regarding existing and new MPAs in terms of zonation and use. To address this need, the aim of this thesis was to investigate reefs that lie between 45 and 75 m and compare them in terms of community structure and function to the relatively well-studied shallow reefs that lie within SCUBA diving depth (<25 m). Ecological collections were made in the centre of a large and well-established MPA, Tsitsikamma National Park, to ensure that data represented non-anthropogenically impacted communities. Data were collected from two study sites; Rheeders Reef, (shallow reef) and Middlebank, a deep reef complex situated near the Storms River Mouth. The first step to address the aim of this study was to obtain baseline data on the distribution patterns of both the macrobenthic invertebrates and fish assemblages. Baseline data were obtained by underwater video methods and included the use of a remotely operated vehicle, baited remote underwater stereo-video systems (stereo-BRUVs) and traditional underwater camera equipment operated by SCUBA divers. To establish functional differences between the two study sites, fatty acid (FA) and stable isotope (SI) analyses were employed. These biomarker techniques provided insight into the importance of different sources of primary production, nutritional condition and species packing. From 360 photoquadrats examined for macrobenthic invertebrate distribution patterns, 161 invertebrates were identified that demonstrated a clear changeover of species along the depth gradient. Species richness was highest on the shallow reef and decreased with an increase in depth. To understand how the measured environmental variables impacted the macrobenthic assemblage data a LINKTREE analysis was performed. LINKTREEs produce hierarchical cluster analysis based on the macrobenthic assemblage data and provide a threshold of environmental variables that correspond to each cluster. The outcome of the LINKTREE analysis indicated that the changeover of species resulted in four distinct clusters, each cluster associated with a particular set of environmental variables that fell within a depth range. On the shallowest sites, the high energy environment resulting from wave action and surge prevented the settlement of suspended particles. The high energy environment of the shallow reef selected for low-growing encrusting species. High light intensities supported great abundances of benthic algae, and as light was lost with increasing depth, algal cover gradually diminished until it was completely absent on the deep reef. The reduced impact of surface wave action on the deep reef caused increased levels of settled suspended particles. The high levels of settled particles likely caused clogging of feeding parts of the encrusting species. Consequently, upright growth forms were more common in the lower energy environment of the deep reef. A total of 48 fish species were identified from 51 stereo-BRUVs samples. Fish assemblages differed significantly between the shallow and deep reefs. The shallowest sites were characterised by many small and juvenile fish species that fed at lower trophic levels. The deep reef supported the majority of the large predatory fish that fed at higher trophic levels. Many species demonstrated depth-related ontogenetic shifts in habitat use, and as such the deep reef hosted the majority of the sexually mature individuals. The fish assemblages also demonstrated a strong association with the macrobenthic clusters identified as habitat types by the LINKTREE analysis. The results from 201 FA and 191 SI samples provided information on specific feeding interactions, but more importantly shed some light on different processes that supported the shallow and deep reef communities. The shallow reef community was characterised by greater diversity of food sources, a pattern that could be explained by the presence of benthic algae and terrestrial inputs. Greater diversity of carbon sources at the bottom of the food web meant that a larger variety of species could be supported. Higher species richness increased the number of distinct taxa that performed similar functions, rendering the shallow reef more redundant and consequently more resilient to disturbance. In contrast, the deep reef demonstrated a food web supported mainly by pelagic production, which was more variable both over space and time. The deep reef was less redundant when compared to the shallow reef, as fewer species demonstrated similar trophic niches. These factors, in addition to the increased presence of sensitive calcareous macrobenthic species on the deep study site, rendered the deep reef more vulnerable to disturbance when compared to the shallow reef. Although the data presented here were from a single study area, the limitations typically associated with these inaccessible and challenging sampling environments made the dataset a significant contribution to the knowledge of reef ecosystems. The study addressed priority research questions for South Africa as identified during the National Biodiversity Assessment. The observable differences in structure, function and vulnerability point to the need for continued protection of our shallow reefs and offshore expansion of our MPA networks. Future research should determine if the patterns identified here are common throughout the Agulhas Ecoregion to provide managers with robust evidence for the extension our MPAs offshore.
- Full Text:
- Date Issued: 2016
Comparative studies on photophysical and optical limiting characterizations of low symmetry phthalocyanine linked to Fe 3 O 4–Ag core–shell or hybrid nanoparticles
- Bankole, Owolabi M, Nyokong, Tebello
- Authors: Bankole, Owolabi M , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188788 , vital:44785 , xlink:href="https://doi.org/10.1039/C6NJ01511E"
- Description: Photophysical and nonlinear optical (NLO) behaviours of low symmetry zinc phthalocyanine (1) linked to Fe3O4/Ag core–shell (represented as Fe/Ag) or Fe3O4–Ag hybrid (represented as FeAg) nanoparticles were investigated in DMSO. Triplet quantum yields and NLO parameters of phthalocyanine improved due to the combined effects of magnetic–metallic nanoparticles. A direct relationship between the increased triplet excited state absorptions by already excited molecules and reverse saturable absorption (RSA) was established as the predominant mechanism responsible for nonlinearity of the samples. Our findings show that, at the same approximate concentrations and conditions, 1-FeAg enhanced the OL potentials of 1 more than 1-Fe/Ag.
- Full Text:
- Date Issued: 2016
- Authors: Bankole, Owolabi M , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188788 , vital:44785 , xlink:href="https://doi.org/10.1039/C6NJ01511E"
- Description: Photophysical and nonlinear optical (NLO) behaviours of low symmetry zinc phthalocyanine (1) linked to Fe3O4/Ag core–shell (represented as Fe/Ag) or Fe3O4–Ag hybrid (represented as FeAg) nanoparticles were investigated in DMSO. Triplet quantum yields and NLO parameters of phthalocyanine improved due to the combined effects of magnetic–metallic nanoparticles. A direct relationship between the increased triplet excited state absorptions by already excited molecules and reverse saturable absorption (RSA) was established as the predominant mechanism responsible for nonlinearity of the samples. Our findings show that, at the same approximate concentrations and conditions, 1-FeAg enhanced the OL potentials of 1 more than 1-Fe/Ag.
- Full Text:
- Date Issued: 2016
Computer simulations of the interaction of human immunodeficiency virus (HIV) aspartic protease with spherical gold nanoparticles: implications in acquired immunodeficiency syndrome (AIDS)
- Whiteley, Chris G, Lee, Duu-Jong
- Authors: Whiteley, Chris G , Lee, Duu-Jong
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67083 , vital:29030 , https://doi.org/10.1088/0957-4484/27/36/365101
- Description: publisher version , The interaction of gold nanoparticles (AuNP) with human immune-deficiency virus aspartic protease (HIVPR) is modelled using a regime of molecular dynamics simulations. The simulations of the 'docking', first as a rigid-body complex, and eventually through flexible-fit analysis, creates 36 different complexes from four initial orientations of the nanoparticle strategically positioned around the surface of the enzyme. The structural deviations of the enzymes from the initial x-ray crystal structure during each docking simulation are assessed by comparative analysis of secondary structural elements, root mean square deviations, B-factors, interactive bonding energies, dihedral angles, radius of gyration (R g), circular dichroism (CD), volume occupied by C α , electrostatic potentials, solvation energies and hydrophobicities. Normalisation of the data narrows the selection from the initial 36 to one 'final' probable structure. It is concluded that, after computer simulations on each of the 36 initial complexes incorporating the 12 different biophysical techniques, the top five complexes are the same no matter which technique is explored. The significance of the present work is an expansion of an earlier study on the molecular dynamic simulation for the interaction of HIVPR with silver nanoparticles. This work is supported by experimental evidence since the initial 'orientation' of the AgNP with the enzyme is the same as the 'final' AuNP-HIVPR complex generated in the present study. The findings will provide insight into the forces of the binding of the HIVPR to AuNP. It is anticipated that the protocol developed in this study will act as a standard process for the interaction of any nanoparticle with any biomedical target.
- Full Text: false
- Date Issued: 2016
- Authors: Whiteley, Chris G , Lee, Duu-Jong
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67083 , vital:29030 , https://doi.org/10.1088/0957-4484/27/36/365101
- Description: publisher version , The interaction of gold nanoparticles (AuNP) with human immune-deficiency virus aspartic protease (HIVPR) is modelled using a regime of molecular dynamics simulations. The simulations of the 'docking', first as a rigid-body complex, and eventually through flexible-fit analysis, creates 36 different complexes from four initial orientations of the nanoparticle strategically positioned around the surface of the enzyme. The structural deviations of the enzymes from the initial x-ray crystal structure during each docking simulation are assessed by comparative analysis of secondary structural elements, root mean square deviations, B-factors, interactive bonding energies, dihedral angles, radius of gyration (R g), circular dichroism (CD), volume occupied by C α , electrostatic potentials, solvation energies and hydrophobicities. Normalisation of the data narrows the selection from the initial 36 to one 'final' probable structure. It is concluded that, after computer simulations on each of the 36 initial complexes incorporating the 12 different biophysical techniques, the top five complexes are the same no matter which technique is explored. The significance of the present work is an expansion of an earlier study on the molecular dynamic simulation for the interaction of HIVPR with silver nanoparticles. This work is supported by experimental evidence since the initial 'orientation' of the AgNP with the enzyme is the same as the 'final' AuNP-HIVPR complex generated in the present study. The findings will provide insight into the forces of the binding of the HIVPR to AuNP. It is anticipated that the protocol developed in this study will act as a standard process for the interaction of any nanoparticle with any biomedical target.
- Full Text: false
- Date Issued: 2016
Conceptualising an epistemically diverse curriculum for a course for academic developers
- Quinn, Lynn, Vorster, Jo-Anne
- Authors: Quinn, Lynn , Vorster, Jo-Anne
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66601 , vital:28970 , https://dx.doi.org/10.20853/30-6-717
- Description: Pre-print , In this conceptual article we use Luckett’s model for an epistemically diverse curriculum, Kitchener’s levels of cognition and Maton’s concepts of knowledge and knowers to analyse a curriculum of a postgraduate diploma in higher education specifically for academic developers. We describe three meta-level frameworks which we offer to our participants to make explicit the pedagogy of the course. Our main argument is that a course which prepares participants to practise in the complex contemporary higher education context requires them to engage with specific kinds of knowledge, ways of thinking and ways of being so that they can contribute towards addressing the numerous and vexing teaching and learning challenges in their institutional contexts. We argue that analyses such as these help to make explicit the organising principles of a curriculum to the curriculum designers themselves who are then able to use the insights to strengthen the design, pedagogy and assessment of their courses. Keywords: academic development, pedagogy.
- Full Text:
- Date Issued: 2016
- Authors: Quinn, Lynn , Vorster, Jo-Anne
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66601 , vital:28970 , https://dx.doi.org/10.20853/30-6-717
- Description: Pre-print , In this conceptual article we use Luckett’s model for an epistemically diverse curriculum, Kitchener’s levels of cognition and Maton’s concepts of knowledge and knowers to analyse a curriculum of a postgraduate diploma in higher education specifically for academic developers. We describe three meta-level frameworks which we offer to our participants to make explicit the pedagogy of the course. Our main argument is that a course which prepares participants to practise in the complex contemporary higher education context requires them to engage with specific kinds of knowledge, ways of thinking and ways of being so that they can contribute towards addressing the numerous and vexing teaching and learning challenges in their institutional contexts. We argue that analyses such as these help to make explicit the organising principles of a curriculum to the curriculum designers themselves who are then able to use the insights to strengthen the design, pedagogy and assessment of their courses. Keywords: academic development, pedagogy.
- Full Text:
- Date Issued: 2016