Food security in a perfect storm: using the ecosystem services framework to increase understanding
- Poppy, G M, Chiotha, S, Eigenbrod, Felix, Harvey, C A, Honzák, M, Hudson, M D, Jarvis, A, Madise, N J, Schreckenberg, Kate, Shackleton, Charlie M, Villa, F, Dawson, T P
- Authors: Poppy, G M , Chiotha, S , Eigenbrod, Felix , Harvey, C A , Honzák, M , Hudson, M D , Jarvis, A , Madise, N J , Schreckenberg, Kate , Shackleton, Charlie M , Villa, F , Dawson, T P
- Date: 2014
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/60952 , vital:27900 , http://dx.doi.org/10.1098/rstb.2012.0288
- Description: Achieving food security in a ‘perfect storm’ scenario is a grand challenge for society. Climate change and an expanding global population act in concert to make global food security even more complex and demanding. As achieving food security and the millennium development goal (MDG) to eradicate hunger influences the attainment of other MDGs, it is imperative that we offer solutions which are complementary and do not oppose one another. Sustainable intensification of agriculture has been proposed as a way to address hunger while also minimizing further environmental impact. However, the desire to raise productivity and yields has historically led to a degraded environment, reduced biodiversity and a reduction in ecosystem services (ES), with the greatest impacts affecting the poor. This paper proposes that the ES framework coupled with a policy response framework, for example Driver-Pressure-State-Impact-Response (DPSIR), can allow food security to be delivered alongside healthy ecosystems, which provide many other valuable services to humankind. Too often, agro-ecosystems have been considered as separate from other natural ecosystems and insufficient attention has been paid to the way in which services can flow to and from the agro-ecosystem to surrounding ecosystems. Highlighting recent research in a large multi-disciplinary project (ASSETS), we illustrate the ES approach to food security using a case study from the Zomba district of Malawi.
- Full Text:
- Date Issued: 2014
- Authors: Poppy, G M , Chiotha, S , Eigenbrod, Felix , Harvey, C A , Honzák, M , Hudson, M D , Jarvis, A , Madise, N J , Schreckenberg, Kate , Shackleton, Charlie M , Villa, F , Dawson, T P
- Date: 2014
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/60952 , vital:27900 , http://dx.doi.org/10.1098/rstb.2012.0288
- Description: Achieving food security in a ‘perfect storm’ scenario is a grand challenge for society. Climate change and an expanding global population act in concert to make global food security even more complex and demanding. As achieving food security and the millennium development goal (MDG) to eradicate hunger influences the attainment of other MDGs, it is imperative that we offer solutions which are complementary and do not oppose one another. Sustainable intensification of agriculture has been proposed as a way to address hunger while also minimizing further environmental impact. However, the desire to raise productivity and yields has historically led to a degraded environment, reduced biodiversity and a reduction in ecosystem services (ES), with the greatest impacts affecting the poor. This paper proposes that the ES framework coupled with a policy response framework, for example Driver-Pressure-State-Impact-Response (DPSIR), can allow food security to be delivered alongside healthy ecosystems, which provide many other valuable services to humankind. Too often, agro-ecosystems have been considered as separate from other natural ecosystems and insufficient attention has been paid to the way in which services can flow to and from the agro-ecosystem to surrounding ecosystems. Highlighting recent research in a large multi-disciplinary project (ASSETS), we illustrate the ES approach to food security using a case study from the Zomba district of Malawi.
- Full Text:
- Date Issued: 2014
Formulation, development and assessment of efavirenz-loaded lipid nanocarriers
- Authors: Makoni, Pedzisai Anotida
- Date: 2014
- Subjects: Nanomedicine , Drug delivery systems , Antiretroviral agents Psychotropic effects , AIDS dementia complex
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/209981 , vital:47448
- Description: The feasibility of incorporating efavirenz (EFV) into innovative solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) using the hot high-pressure homogenization (HHPH) technique was investigated in an attempt to address the shortcomings in therapy associated with the use of conventional dosage forms. The shortcomings include the unpalatable taste of API in solution, instability in the presence of light when in solution and psychiatric side effects of the API. In particular, sustained release approaches may reduce or limit the incidence of adverse psychiatric effects of EFV and alleviate Acquired Immune Deficiency Syndrome (AIDS)-related complications such as AIDS Dementia Complex (ADC) in patients, ultimately improving their quality of life. Prior to initiating pre-formulation, formulation development and optimization studies of EFV-loaded SLN and/or NLC, Response Surface Methodology (RSM) in conjunction with central composite design (CCD), was used to develop and validate suitable methods for the quantitative determination of EFV in pharmaceutical formulations and for monitoring EFV release from SLN and/or NLC in vitro. Simple, accurate, precise, sensitive and stabilityindicating reversed phase-high performance liquid chromatography (RP-HPLC) methods with UV and electrochemical (EC) detection were developed, validated and optimized for in vitro analysis of EFV in formulations. On the basis of risk-to-benefit ratio the RP-HPLC method with UV detection was selected as the most suitable for the quantitative determination of EFV in pharmaceutical formulations, and was applied to in vitro release studies of EFV from SLN and/or NLC. Pre-formulation studies were undertaken to investigate the thermal stability of EFV so as to facilitate the selection of lipid excipients for the manufacture of nanocarriers, and to establish their compatibility with EFV. It was found that EFV was thermostable up to a temperature of approximately 200°C, indicating that HHPH could be used for the manufacture of EFV-loaded SLN and/or NLC. Lipid screening revealed that EFV is highly soluble in solid and liquid lipids, with glyceryl monostearate and Transcutol® HP showing the best solubilizing potential for EFV. Glyceryl monostearate exists in a stable β-modification prior to exposure to heat, but exists in the α-polymorphic modification following exposure to heat. It was established that the addition of Transcutol® HP to glyceryl monostearate revealed the co-existence of the α- and β’-polymorphic modifications, thereby revealing the existence of the modifications in NLC produced from the optimum lipid combination. Furthermore, an investigation of binary mixtures of EFV/glyceryl monostearate and glyceryl monostearate/Transcutol® HP, in addition to eutectic mixtures of EFV, glyceryl monostearate and Transcutol® HP, revealed no interaction between EFV and the lipids selected for the production of the nanocarriers. Due to the significantly higher solubility of EFV in Transcutol® HP than in to glyceryl monostearate, NLC are most likely to have a higher LC and EE than SLN. In addition, the existence of both the α- and β’-polymorphic modifications in the binary mixture of the lipid implies that EFV expulsion on prolonged storage is unlikely to occur from NLC when compared to SLN. Consequently formulation development and optimization studies of SLN and NLC were performed to investigate the potential to deliver EFV from a novel technology with an appropriate LC and EE for EFV. Tween®80 was selected for use in these formulations as the use of this surfactant facilitates the targeting of nanocarriers to the CNS. RSM in conjunction with a Box-Behnken Design (BBD) was used to establish the effects of process variables, such as number of homogenization cycles and pressure, in addition to formulation variables such as amount of EFV and Tween®80 on the particle size (PS), polydispersity index (PDI), zeta potential (ZP), visual assessment (VA) and release rate (RR) of EFV after 24 hours. In addition the LC and EE, degree of crystallinity and lipid modification, shape and surface morphology of the optimized batches were investigated to ensure that EFV-loaded SLN and NLC of desirable quality were produced. On the day of manufacture the mean PS and PDI of EFV-loaded SLN was 59.00 ± 23.16 nm and 0.382 ± 0.054 respectively. The mean PS and PDI of EFV-loaded NLC was 34.73 ± 0.7709 nm and 0.394 ± 0.027 respectively. The formulations were in the nanometer range and exhibited a narrow particle size distribution, as indicated by the PDI values. The ZP values for optimized SLN and NLC generated on the day of manufacture using HPLC grade water as the dispersion medium were -32.5 ± 4.99 mV and -22.4 ± 3.72 mV respectively. In addition the optimized batches of SLN and NLC revealed a decrease in crystallinity in comparison to bulk lipid material. DSC, WAXS and FT-IR revealed that EFV was molecularly dispersed in the nanocarriers. In addition EFV-loaded SLN existed in a single α-polymorphic form, whereas EFV-loaded NLC exhibited the co-existence of α- and β’-polymorphic forms. Generally SLN and NLC were spherically shaped when viewed under transmission electron microscopy (TEM) and scanning electron microscopy (SEM). On the day of manufacture the EE and LC of EFVloaded SLN was found to be 96.77 ± 0.453 % and 9.68 ± 1.772 % respectively. The EE and LC of EFV-loaded NLC was 99.93 ± 0.413 and 9.995 ± 0.672 respectively. The release profiles for the optimized formulations of SLN and NLC exhibited an initial burst release over the first 0-3 hours of testing, after which the release was sustained for up to 24 hours. The cumulative % EFV released over 24 hours was higher from SLN (91.5±3.423 %) than that observed for NLC (73.6±4.34 %). Stability studies performed for 8 weeks on the optimized batches of the SLN and the NLC were also conducted so as to ensure product quality. The formulations were assessed in terms of parameters considered benchmarks of stability, and included ZP, PS, PDI, LC and EE. Generally these parameters remained unchanged following storage for 8 weeks at 25°C/60% RH but showed considerable changes following storage for 8 weeks at 40°C/75% RH. These studies reveal that SLN and NLC when stored at 25°C/60% RH have the potential to be used as colloidal delivery systems for EFV that have the potential to protect EFV from photodegradation and sustain release into brain tissue. The latter will ultimately reduce or limit the incidence of adverse psychiatric effects and potentially alleviate AIDS-related complications such as ADC in patients with HIV/AIDS, ultimately improving their quality of life. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2014
- Full Text:
- Date Issued: 2014
- Authors: Makoni, Pedzisai Anotida
- Date: 2014
- Subjects: Nanomedicine , Drug delivery systems , Antiretroviral agents Psychotropic effects , AIDS dementia complex
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/209981 , vital:47448
- Description: The feasibility of incorporating efavirenz (EFV) into innovative solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) using the hot high-pressure homogenization (HHPH) technique was investigated in an attempt to address the shortcomings in therapy associated with the use of conventional dosage forms. The shortcomings include the unpalatable taste of API in solution, instability in the presence of light when in solution and psychiatric side effects of the API. In particular, sustained release approaches may reduce or limit the incidence of adverse psychiatric effects of EFV and alleviate Acquired Immune Deficiency Syndrome (AIDS)-related complications such as AIDS Dementia Complex (ADC) in patients, ultimately improving their quality of life. Prior to initiating pre-formulation, formulation development and optimization studies of EFV-loaded SLN and/or NLC, Response Surface Methodology (RSM) in conjunction with central composite design (CCD), was used to develop and validate suitable methods for the quantitative determination of EFV in pharmaceutical formulations and for monitoring EFV release from SLN and/or NLC in vitro. Simple, accurate, precise, sensitive and stabilityindicating reversed phase-high performance liquid chromatography (RP-HPLC) methods with UV and electrochemical (EC) detection were developed, validated and optimized for in vitro analysis of EFV in formulations. On the basis of risk-to-benefit ratio the RP-HPLC method with UV detection was selected as the most suitable for the quantitative determination of EFV in pharmaceutical formulations, and was applied to in vitro release studies of EFV from SLN and/or NLC. Pre-formulation studies were undertaken to investigate the thermal stability of EFV so as to facilitate the selection of lipid excipients for the manufacture of nanocarriers, and to establish their compatibility with EFV. It was found that EFV was thermostable up to a temperature of approximately 200°C, indicating that HHPH could be used for the manufacture of EFV-loaded SLN and/or NLC. Lipid screening revealed that EFV is highly soluble in solid and liquid lipids, with glyceryl monostearate and Transcutol® HP showing the best solubilizing potential for EFV. Glyceryl monostearate exists in a stable β-modification prior to exposure to heat, but exists in the α-polymorphic modification following exposure to heat. It was established that the addition of Transcutol® HP to glyceryl monostearate revealed the co-existence of the α- and β’-polymorphic modifications, thereby revealing the existence of the modifications in NLC produced from the optimum lipid combination. Furthermore, an investigation of binary mixtures of EFV/glyceryl monostearate and glyceryl monostearate/Transcutol® HP, in addition to eutectic mixtures of EFV, glyceryl monostearate and Transcutol® HP, revealed no interaction between EFV and the lipids selected for the production of the nanocarriers. Due to the significantly higher solubility of EFV in Transcutol® HP than in to glyceryl monostearate, NLC are most likely to have a higher LC and EE than SLN. In addition, the existence of both the α- and β’-polymorphic modifications in the binary mixture of the lipid implies that EFV expulsion on prolonged storage is unlikely to occur from NLC when compared to SLN. Consequently formulation development and optimization studies of SLN and NLC were performed to investigate the potential to deliver EFV from a novel technology with an appropriate LC and EE for EFV. Tween®80 was selected for use in these formulations as the use of this surfactant facilitates the targeting of nanocarriers to the CNS. RSM in conjunction with a Box-Behnken Design (BBD) was used to establish the effects of process variables, such as number of homogenization cycles and pressure, in addition to formulation variables such as amount of EFV and Tween®80 on the particle size (PS), polydispersity index (PDI), zeta potential (ZP), visual assessment (VA) and release rate (RR) of EFV after 24 hours. In addition the LC and EE, degree of crystallinity and lipid modification, shape and surface morphology of the optimized batches were investigated to ensure that EFV-loaded SLN and NLC of desirable quality were produced. On the day of manufacture the mean PS and PDI of EFV-loaded SLN was 59.00 ± 23.16 nm and 0.382 ± 0.054 respectively. The mean PS and PDI of EFV-loaded NLC was 34.73 ± 0.7709 nm and 0.394 ± 0.027 respectively. The formulations were in the nanometer range and exhibited a narrow particle size distribution, as indicated by the PDI values. The ZP values for optimized SLN and NLC generated on the day of manufacture using HPLC grade water as the dispersion medium were -32.5 ± 4.99 mV and -22.4 ± 3.72 mV respectively. In addition the optimized batches of SLN and NLC revealed a decrease in crystallinity in comparison to bulk lipid material. DSC, WAXS and FT-IR revealed that EFV was molecularly dispersed in the nanocarriers. In addition EFV-loaded SLN existed in a single α-polymorphic form, whereas EFV-loaded NLC exhibited the co-existence of α- and β’-polymorphic forms. Generally SLN and NLC were spherically shaped when viewed under transmission electron microscopy (TEM) and scanning electron microscopy (SEM). On the day of manufacture the EE and LC of EFVloaded SLN was found to be 96.77 ± 0.453 % and 9.68 ± 1.772 % respectively. The EE and LC of EFV-loaded NLC was 99.93 ± 0.413 and 9.995 ± 0.672 respectively. The release profiles for the optimized formulations of SLN and NLC exhibited an initial burst release over the first 0-3 hours of testing, after which the release was sustained for up to 24 hours. The cumulative % EFV released over 24 hours was higher from SLN (91.5±3.423 %) than that observed for NLC (73.6±4.34 %). Stability studies performed for 8 weeks on the optimized batches of the SLN and the NLC were also conducted so as to ensure product quality. The formulations were assessed in terms of parameters considered benchmarks of stability, and included ZP, PS, PDI, LC and EE. Generally these parameters remained unchanged following storage for 8 weeks at 25°C/60% RH but showed considerable changes following storage for 8 weeks at 40°C/75% RH. These studies reveal that SLN and NLC when stored at 25°C/60% RH have the potential to be used as colloidal delivery systems for EFV that have the potential to protect EFV from photodegradation and sustain release into brain tissue. The latter will ultimately reduce or limit the incidence of adverse psychiatric effects and potentially alleviate AIDS-related complications such as ADC in patients with HIV/AIDS, ultimately improving their quality of life. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2014
- Full Text:
- Date Issued: 2014
General structural and functional features of molecular chaperones:
- Edkins, Adrienne L, Boshoff, Aileen
- Authors: Edkins, Adrienne L , Boshoff, Aileen
- Date: 2014
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/164808 , vital:41174 , ISBN 978-94-007-7437-7 , DOI: 10.1007/978-94-007-7438-4_2
- Description: Molecular chaperones are a group of structurally diverse and highly conserved ubiquitous proteins. They play crucial roles in facilitating the correct folding of proteins in vivo by preventing protein aggregation or facilitating the appropriate folding and assembly of proteins. Heat shock proteins form the major class of molecular chaperones that are responsible for protein folding events in the cell. This is achieved by ATP-dependent (folding machines) or ATP-independent mechanisms (holders). Heat shock proteins are induced by a variety of stresses, besides heat shock. The large and varied heat shock protein class is categorised into several subfamilies based on their sizes in kDa namely, small Hsps (HSPB), Hsp40 (DNAJ), Hsp60 (HSPD/E; Chaperonins), Hsp70 (HSPA), Hsp90 (HSPC), and Hsp100.
- Full Text:
- Date Issued: 2014
- Authors: Edkins, Adrienne L , Boshoff, Aileen
- Date: 2014
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/164808 , vital:41174 , ISBN 978-94-007-7437-7 , DOI: 10.1007/978-94-007-7438-4_2
- Description: Molecular chaperones are a group of structurally diverse and highly conserved ubiquitous proteins. They play crucial roles in facilitating the correct folding of proteins in vivo by preventing protein aggregation or facilitating the appropriate folding and assembly of proteins. Heat shock proteins form the major class of molecular chaperones that are responsible for protein folding events in the cell. This is achieved by ATP-dependent (folding machines) or ATP-independent mechanisms (holders). Heat shock proteins are induced by a variety of stresses, besides heat shock. The large and varied heat shock protein class is categorised into several subfamilies based on their sizes in kDa namely, small Hsps (HSPB), Hsp40 (DNAJ), Hsp60 (HSPD/E; Chaperonins), Hsp70 (HSPA), Hsp90 (HSPC), and Hsp100.
- Full Text:
- Date Issued: 2014
Gold mineralization in a high grade metamorphic terrane in the Handeni District, Eastern Tanzania
- Bitesigirwe, Godfrey Stephen
- Authors: Bitesigirwe, Godfrey Stephen
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54756 , vital:26609
- Description: Most orogenic type gold deposits are formed under low greenschist facies to mid amphibolite facies metamorphic conditions and deposition is either structurally or lithologically controlled. A few known gold deposits found in high grade metamorphic terranes include those in the Yilgarn craton in Australia, Renco in Zimbabwe, Hemlo in Canada and the recently discovered Handeni deposit in Tanzania. Within Tanzania, gold deposits are mainly hosted in Archaean low grade metamorphic rocks commonly known as the Lake Victoria greenstone belt. The greenstone belts of Tanzania are of Nyanzian age (> 2.5Ga) and are located to the south and east of Lake Victoria on the Tanzania craton. The Tanzania Craton is surrounded by Usagaran 1.9 Ga rocks (the east African orogenic belt (EAO) better known as the Mozambique belt) to the east and the Ubendian belt to the south and west. Published reports show that the eastern part of the Tanzania Craton is dominated by the fragments of Archaean rocks. Metamorphism along East Africa and the Tanzania Craton is due to several geological events. These geological events include the intrusion of granites in the Archaean Tanzania Craton (3 Ga), subduction of ocean plate resulted to the formation of Usagaran belt (1.9 Ga), opening and closure of Mozambique Ocean, which resulted in the formation of the Mozambique belt between 700 – 800 Ma and the Pan African orogeny at 640 – 620 Ma, which is associated with the formation of Gondwana. It is believed that fragments from the Archaean Tanzania craton were re - metamorphosed during these events. The Handeni project (the focus of this thesis) is located in the northern portion of the eastern part of the Usagaran belt (1.9 Ga) comprising the eastern part of Archaean Tanzania Craton. The area is characterized by Proterozic rocks of basaltic composition. The documented 2.7 Ga rocks at the Kilindi Handeni Superterrane at the northern part of the Usagaran belt correlate well with 2.7 Ga of Nyanzian rocks of Archaean Tanzania craton. The Handeni project area is geologically dominated by metamorphosed and deformed units of quartzofeldspathic gneisses, migmatitic gneiss, garnet silicified rock, garnetiferous amphibolite, garnetiferous granulite, graphitic schist and hornblende pyroxenite. Intensive deformation features that were developed include folds (sheath folds, micro and macro scales), faults, shears and regional thrusts. This thesis focuses on identifying the protolith of the rocks, alteration minerals, and metamorphic assemblages in the project area in order to understand the timing of gold mineralization. Geological investigation of core, ore petrology and mineralogy, mineral composition by using JEOL microprobe analysis and XRF analysis of bulk rocks were utilized. All the analytical work was done at the Geology laboratory, Rhodes University. Petrographic analysis shows that the rocks sampled in the study area are characterized by alteration minerals such as calcite, dolomite and sericite. Sulphide minerals including chalcopyrite, pyrrhotite, pyrite, pentlandite and gersdorffite were identified. Gold mineralization is associated with disseminated sulphides in association with trace amounts of base metals. Four rock types were proposed as host rocks for the mineralization, namely garnet silicified rock with superimposed quartz veins, garnetiferous amphibolite, garnetiferous granulite and hornblende pyroxenite. Fold troughs, filled fractures associated with episodes of folding, quartz veins and shear zones are suggested as gold precipitation sites. The presence of high grade metamorphic rocks containing gold, intermediate to low grade assemblages with sulphides and associated hydrothermal alteration as well as a complex deformation history suggests that the Handeni mineralization took place over an extended time period stretching from a ductile to a brittle environment.
- Full Text:
- Date Issued: 2014
- Authors: Bitesigirwe, Godfrey Stephen
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54756 , vital:26609
- Description: Most orogenic type gold deposits are formed under low greenschist facies to mid amphibolite facies metamorphic conditions and deposition is either structurally or lithologically controlled. A few known gold deposits found in high grade metamorphic terranes include those in the Yilgarn craton in Australia, Renco in Zimbabwe, Hemlo in Canada and the recently discovered Handeni deposit in Tanzania. Within Tanzania, gold deposits are mainly hosted in Archaean low grade metamorphic rocks commonly known as the Lake Victoria greenstone belt. The greenstone belts of Tanzania are of Nyanzian age (> 2.5Ga) and are located to the south and east of Lake Victoria on the Tanzania craton. The Tanzania Craton is surrounded by Usagaran 1.9 Ga rocks (the east African orogenic belt (EAO) better known as the Mozambique belt) to the east and the Ubendian belt to the south and west. Published reports show that the eastern part of the Tanzania Craton is dominated by the fragments of Archaean rocks. Metamorphism along East Africa and the Tanzania Craton is due to several geological events. These geological events include the intrusion of granites in the Archaean Tanzania Craton (3 Ga), subduction of ocean plate resulted to the formation of Usagaran belt (1.9 Ga), opening and closure of Mozambique Ocean, which resulted in the formation of the Mozambique belt between 700 – 800 Ma and the Pan African orogeny at 640 – 620 Ma, which is associated with the formation of Gondwana. It is believed that fragments from the Archaean Tanzania craton were re - metamorphosed during these events. The Handeni project (the focus of this thesis) is located in the northern portion of the eastern part of the Usagaran belt (1.9 Ga) comprising the eastern part of Archaean Tanzania Craton. The area is characterized by Proterozic rocks of basaltic composition. The documented 2.7 Ga rocks at the Kilindi Handeni Superterrane at the northern part of the Usagaran belt correlate well with 2.7 Ga of Nyanzian rocks of Archaean Tanzania craton. The Handeni project area is geologically dominated by metamorphosed and deformed units of quartzofeldspathic gneisses, migmatitic gneiss, garnet silicified rock, garnetiferous amphibolite, garnetiferous granulite, graphitic schist and hornblende pyroxenite. Intensive deformation features that were developed include folds (sheath folds, micro and macro scales), faults, shears and regional thrusts. This thesis focuses on identifying the protolith of the rocks, alteration minerals, and metamorphic assemblages in the project area in order to understand the timing of gold mineralization. Geological investigation of core, ore petrology and mineralogy, mineral composition by using JEOL microprobe analysis and XRF analysis of bulk rocks were utilized. All the analytical work was done at the Geology laboratory, Rhodes University. Petrographic analysis shows that the rocks sampled in the study area are characterized by alteration minerals such as calcite, dolomite and sericite. Sulphide minerals including chalcopyrite, pyrrhotite, pyrite, pentlandite and gersdorffite were identified. Gold mineralization is associated with disseminated sulphides in association with trace amounts of base metals. Four rock types were proposed as host rocks for the mineralization, namely garnet silicified rock with superimposed quartz veins, garnetiferous amphibolite, garnetiferous granulite and hornblende pyroxenite. Fold troughs, filled fractures associated with episodes of folding, quartz veins and shear zones are suggested as gold precipitation sites. The presence of high grade metamorphic rocks containing gold, intermediate to low grade assemblages with sulphides and associated hydrothermal alteration as well as a complex deformation history suggests that the Handeni mineralization took place over an extended time period stretching from a ductile to a brittle environment.
- Full Text:
- Date Issued: 2014
Group work as 'terrains of learning' for students in South African higher education
- Thondhlana, Gladman, Belluigi, Dina Z
- Authors: Thondhlana, Gladman , Belluigi, Dina Z
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67636 , vital:29123 , https://journals.co.za/content/persed/32/4/EJC164258
- Description: Publisher version , A common global perception of group work in the higher education context is that it has the potential to act as a platform which can enable student learning by means of interactions, shared diverse experiences, deep engagement with subject concepts and the achievement of tasks collaboratively. Indeed, in different socio-economic, historical and institutional contexts, group work activities have become levers by which deeper learning could be achieved. Drawing on perceptions and experiences of group work among environmental science students at a South African university, we investigate the ways in which group work could be more expansively viewed as 'terrains of learning' for students. The results in general indicate that students have positive perceptions and experiences of group work, though problematic elements are evident. This particular case study points to the attention that should be paid to understanding issues of background, ethnicity and various student personalities which could hinder or enable the desired student learning. Such an understanding could contribute to debates regarding the achievement of higher quality learning, given issues of diversity and transformation in the South African higher education context.
- Full Text: false
- Date Issued: 2014
- Authors: Thondhlana, Gladman , Belluigi, Dina Z
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67636 , vital:29123 , https://journals.co.za/content/persed/32/4/EJC164258
- Description: Publisher version , A common global perception of group work in the higher education context is that it has the potential to act as a platform which can enable student learning by means of interactions, shared diverse experiences, deep engagement with subject concepts and the achievement of tasks collaboratively. Indeed, in different socio-economic, historical and institutional contexts, group work activities have become levers by which deeper learning could be achieved. Drawing on perceptions and experiences of group work among environmental science students at a South African university, we investigate the ways in which group work could be more expansively viewed as 'terrains of learning' for students. The results in general indicate that students have positive perceptions and experiences of group work, though problematic elements are evident. This particular case study points to the attention that should be paid to understanding issues of background, ethnicity and various student personalities which could hinder or enable the desired student learning. Such an understanding could contribute to debates regarding the achievement of higher quality learning, given issues of diversity and transformation in the South African higher education context.
- Full Text: false
- Date Issued: 2014
Guardian of the furnace: mitochondria, TRAP1, ROS and stem cell maintenance
- Kadye, Rose, Kramer, Adam H, Joos-Vandewalle, Julia, Parsons, Michelle, Njengele, Zikhona, Hoppe, Heinrich, Prinsloo, Earl
- Authors: Kadye, Rose , Kramer, Adam H , Joos-Vandewalle, Julia , Parsons, Michelle , Njengele, Zikhona , Hoppe, Heinrich , Prinsloo, Earl
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431119 , vital:72745 , xlink:href="https://doi.org/10.1002/iub.1234"
- Description: Mitochondria are key to eukaryotic cell survival and their activity is linked to generation of reactive oxygen species (ROS) which in turn acts as both an intracellular signal and an effective executioner of cells with regards to cellular senescence. The mitochondrial molecular chaperone tumor necrosis factor receptor associated protein 1 (TRAP1) is often termed the cytoprotective chaperone for its role in cancer cell survival and protection from apoptosis. Here, we hypothesize that TRAP1 serves to modulate mitochondrial activity in stem cell maintenance, survival and differentiation.
- Full Text:
- Date Issued: 2014
- Authors: Kadye, Rose , Kramer, Adam H , Joos-Vandewalle, Julia , Parsons, Michelle , Njengele, Zikhona , Hoppe, Heinrich , Prinsloo, Earl
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431119 , vital:72745 , xlink:href="https://doi.org/10.1002/iub.1234"
- Description: Mitochondria are key to eukaryotic cell survival and their activity is linked to generation of reactive oxygen species (ROS) which in turn acts as both an intracellular signal and an effective executioner of cells with regards to cellular senescence. The mitochondrial molecular chaperone tumor necrosis factor receptor associated protein 1 (TRAP1) is often termed the cytoprotective chaperone for its role in cancer cell survival and protection from apoptosis. Here, we hypothesize that TRAP1 serves to modulate mitochondrial activity in stem cell maintenance, survival and differentiation.
- Full Text:
- Date Issued: 2014
Happiness, national pride and the 2010 World Cup
- Authors: Moller, Valerie
- Date: 2014
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/67265 , vital:29065 , https://www.taylorfrancis.com/books/e/9781317664185
- Description: publisher version , The potential for national pride to take on shades of both the authentic and the hubristic is reflected in the International Social Survey Program's (ISSP) use of two different multi-item measures of national pride, a general and a domain-specific one. In contrast, domain-specific national pride is characterized as 'not overtly nationalistic, imperialistic, nor chauvinistic' and is expressed as positive feelings towards national accomplishments in a range of domains including arts, science and sport. Most scholars who take an interest in the impact of sport mega-events acknowledge that national pride is related to concepts such as patriotism and nationalism whose meanings are difficult to disentangle. The South African Social Attitudes Survey (SASAS), which has tracked the attitudes of South African adults around the 2010 World Cup, has confirmed this idea. The longitudinal SASAS study found that subsequent to the event, there was an enormous upswing in the belief that the World Cup had a positive impact on social cohesion.
- Full Text: false
- Date Issued: 2014
- Authors: Moller, Valerie
- Date: 2014
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/67265 , vital:29065 , https://www.taylorfrancis.com/books/e/9781317664185
- Description: publisher version , The potential for national pride to take on shades of both the authentic and the hubristic is reflected in the International Social Survey Program's (ISSP) use of two different multi-item measures of national pride, a general and a domain-specific one. In contrast, domain-specific national pride is characterized as 'not overtly nationalistic, imperialistic, nor chauvinistic' and is expressed as positive feelings towards national accomplishments in a range of domains including arts, science and sport. Most scholars who take an interest in the impact of sport mega-events acknowledge that national pride is related to concepts such as patriotism and nationalism whose meanings are difficult to disentangle. The South African Social Attitudes Survey (SASAS), which has tracked the attitudes of South African adults around the 2010 World Cup, has confirmed this idea. The longitudinal SASAS study found that subsequent to the event, there was an enormous upswing in the belief that the World Cup had a positive impact on social cohesion.
- Full Text: false
- Date Issued: 2014
Happiness, socioeconomic status, and family functioning in South African households
- Botha, Ferdie, Booysen, Frikkie
- Authors: Botha, Ferdie , Booysen, Frikkie
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396075 , vital:69148 , xlink:href="https://doi.org/10.1007/s11205-013-0485-6"
- Description: This paper examines how SES relates to individual happiness, while also controlling for family functioning; the latter measured by the Family Attachment and Changeability Index 8 (FACI8). An individual-, household-, and subjective SES index are developed via multiple correspondence analyses (MCA). Using data from the 2012 South African Social Attitudes Survey (SASAS), the paper employs structural equation modelling (SEM) to explore the relationship between happiness, SES, and family functioning. Multiple-group SEM (MGSEM) is employed to examine the association between happiness and family functioning across quartiles of the three SES indices. The results reveal that higher SES is significantly related to greater happiness, with the role of household- and subjective SES being stronger than individual SES. Furthermore, improved levels of family changeability are positively associated with happiness, whereas there is no relationship between happiness and family attachment. Overall, levels of family changeability and individual happiness are likely to benefit from improvements in socioeconomic status.
- Full Text:
- Date Issued: 2014
- Authors: Botha, Ferdie , Booysen, Frikkie
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396075 , vital:69148 , xlink:href="https://doi.org/10.1007/s11205-013-0485-6"
- Description: This paper examines how SES relates to individual happiness, while also controlling for family functioning; the latter measured by the Family Attachment and Changeability Index 8 (FACI8). An individual-, household-, and subjective SES index are developed via multiple correspondence analyses (MCA). Using data from the 2012 South African Social Attitudes Survey (SASAS), the paper employs structural equation modelling (SEM) to explore the relationship between happiness, SES, and family functioning. Multiple-group SEM (MGSEM) is employed to examine the association between happiness and family functioning across quartiles of the three SES indices. The results reveal that higher SES is significantly related to greater happiness, with the role of household- and subjective SES being stronger than individual SES. Furthermore, improved levels of family changeability are positively associated with happiness, whereas there is no relationship between happiness and family attachment. Overall, levels of family changeability and individual happiness are likely to benefit from improvements in socioeconomic status.
- Full Text:
- Date Issued: 2014
Higher education studies as a field of research
- Authors: McKenna, Sioux
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187405 , vital:44631 , xlink:href="https://hdl.handle.net/10520/EJC161436"
- Description: The field of Higher Education Studies is a rapidly growing one in South Africa and abroad but there has been little systematic review of the form this growth is taking. This article presents a case study of higher education research by considering a newly formed Higher Education Studies doctoral programme. The programme comprises 29 PhD scholars in 2014, all engaged in research on some aspect of higher education. The description of the PhD programme, the PhD scholars and what their research topics are, reveals a picture of the broad range of concerns within the field of Higher Education Studies and suggests that the field is a region, in Bernstein's terms. This means that it draws on multiple disciplines and looks both to the values and structures of those disciplines and to the professional world of work. It is argued that the strengthening of the epistemological base of Higher Education Studies is necessary for higher education research to move forwards with enhanced relational and positional autonomy.
- Full Text:
- Date Issued: 2014
- Authors: McKenna, Sioux
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187405 , vital:44631 , xlink:href="https://hdl.handle.net/10520/EJC161436"
- Description: The field of Higher Education Studies is a rapidly growing one in South Africa and abroad but there has been little systematic review of the form this growth is taking. This article presents a case study of higher education research by considering a newly formed Higher Education Studies doctoral programme. The programme comprises 29 PhD scholars in 2014, all engaged in research on some aspect of higher education. The description of the PhD programme, the PhD scholars and what their research topics are, reveals a picture of the broad range of concerns within the field of Higher Education Studies and suggests that the field is a region, in Bernstein's terms. This means that it draws on multiple disciplines and looks both to the values and structures of those disciplines and to the professional world of work. It is argued that the strengthening of the epistemological base of Higher Education Studies is necessary for higher education research to move forwards with enhanced relational and positional autonomy.
- Full Text:
- Date Issued: 2014
Homestead greening is widespread amongst the urban poor in three medium-sized South African towns
- Kaoma, Humphrey, Shackleton, Charlie M
- Authors: Kaoma, Humphrey , Shackleton, Charlie M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398291 , vital:69398 , xlink:href="https://doi.org/10.1007/s11252-014-0362-3"
- Description: Trees in urban areas are important sources of ecosystem services and benefits. In most towns the bulk of urban biodiversity, and trees specifically, are found in homestead gardens. But there is only limited understanding of the tree holdings in such gardens, and how they vary within and between towns, especially for developing countries where rapid urbanisation and high poverty influence the use of and reliance on land and local resources. We report on the nature of tree holdings in private gardens of poorer suburbs in three medium-sized towns along a gradient of decreasing mean annual rainfall in northern South Africa. A total of 3 217 trees were enumerated across 450 randomly selected homesteads. Most (90 %) households had at least one tree on their homestead, with an average of 7.7 ± 6.1 trees. Most householders had planted the trees themselves. The density of trees declined along the moisture gradient. Within towns, tree density was positively related to garden size, which in turn was related to relative affluence and age of the suburb. Newer and poorer suburbs had the fewest trees per household. Sixty-two tree species were recorded, which were dominated by alien species, especially fruit trees. There was no relationship between the moisture gradient and tree species richness per household, but within towns there was a difference between suburbs, being lowest in the newest suburbs. Numbers of trees and species per household was positively related to age of the household head.
- Full Text:
- Date Issued: 2014
- Authors: Kaoma, Humphrey , Shackleton, Charlie M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398291 , vital:69398 , xlink:href="https://doi.org/10.1007/s11252-014-0362-3"
- Description: Trees in urban areas are important sources of ecosystem services and benefits. In most towns the bulk of urban biodiversity, and trees specifically, are found in homestead gardens. But there is only limited understanding of the tree holdings in such gardens, and how they vary within and between towns, especially for developing countries where rapid urbanisation and high poverty influence the use of and reliance on land and local resources. We report on the nature of tree holdings in private gardens of poorer suburbs in three medium-sized towns along a gradient of decreasing mean annual rainfall in northern South Africa. A total of 3 217 trees were enumerated across 450 randomly selected homesteads. Most (90 %) households had at least one tree on their homestead, with an average of 7.7 ± 6.1 trees. Most householders had planted the trees themselves. The density of trees declined along the moisture gradient. Within towns, tree density was positively related to garden size, which in turn was related to relative affluence and age of the suburb. Newer and poorer suburbs had the fewest trees per household. Sixty-two tree species were recorded, which were dominated by alien species, especially fruit trees. There was no relationship between the moisture gradient and tree species richness per household, but within towns there was a difference between suburbs, being lowest in the newest suburbs. Numbers of trees and species per household was positively related to age of the household head.
- Full Text:
- Date Issued: 2014
How to establish a bioinformatics postgraduate degree programme—a case study from South Africa
- Machanick, Philip, Tastan Bishop, Özlem
- Authors: Machanick, Philip , Tastan Bishop, Özlem
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124641 , vital:35641 , https://doi.10.1093/bib/bbu014
- Description: The Research Unit in Bioinformatics at Rhodes University (RUBi), South Africa, offers a Masters of Science in Bioinformatics.Growing demand for bioinformatics qualifications results in applications from across Africa.Courses aim to bridge gaps in the diverse backgrounds of students who range from biologists with no prior computing exposure to computer scientists with no biology background. The programme is evenly split between coursework and research, with diverse modules from a range of departments coveringmathematics, statistics, computer science and biology, with emphasis on application to bioinformatics research. The early focus on research helps bring students up to speed with working as a researcher. We measure success of the programme by the high rate of subsequent entry to PhD study: 10 of 14 students who completed in the years 2011-2013.
- Full Text:
- Date Issued: 2014
- Authors: Machanick, Philip , Tastan Bishop, Özlem
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124641 , vital:35641 , https://doi.10.1093/bib/bbu014
- Description: The Research Unit in Bioinformatics at Rhodes University (RUBi), South Africa, offers a Masters of Science in Bioinformatics.Growing demand for bioinformatics qualifications results in applications from across Africa.Courses aim to bridge gaps in the diverse backgrounds of students who range from biologists with no prior computing exposure to computer scientists with no biology background. The programme is evenly split between coursework and research, with diverse modules from a range of departments coveringmathematics, statistics, computer science and biology, with emphasis on application to bioinformatics research. The early focus on research helps bring students up to speed with working as a researcher. We measure success of the programme by the high rate of subsequent entry to PhD study: 10 of 14 students who completed in the years 2011-2013.
- Full Text:
- Date Issued: 2014
HPLC method for simultaneous analysis of ranitidine and metronidazole in dosage forms
- King'ori, Loti D, Walker, Roderick B
- Authors: King'ori, Loti D , Walker, Roderick B
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184790 , vital:44272 , xlink:href="https://doi.org/10.14233/ajchem.2014.15432"
- Description: A simple, rapid, precise and accurate stability indicating HPLC method for the simultaneous analysis of metronidazole and ranitidine in dosage forms has been developed and validated. Calibration curves for metronidazole and ranitidine exhibited linearity (R2 = 0.9995 for both compounds) over the concentration ranges investigated. The method was sensitive, selective and accurate for both compounds. Both drugs were found to be stable following acid hydrolysis studies. However, following alkali hydrolysis degradation of both compounds was observed. Furthermore metronidazole appeared to be stable following oxidative studies however ranitidine underwent complete degradation under these conditions. Both drugs were well resolved from the degradation products. The stability indicating chromatographic method has the necessary precision and accuracy for the simultaneous analysis of metronidazole and ranitidine in dosage forms.
- Full Text:
- Date Issued: 2014
- Authors: King'ori, Loti D , Walker, Roderick B
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184790 , vital:44272 , xlink:href="https://doi.org/10.14233/ajchem.2014.15432"
- Description: A simple, rapid, precise and accurate stability indicating HPLC method for the simultaneous analysis of metronidazole and ranitidine in dosage forms has been developed and validated. Calibration curves for metronidazole and ranitidine exhibited linearity (R2 = 0.9995 for both compounds) over the concentration ranges investigated. The method was sensitive, selective and accurate for both compounds. Both drugs were found to be stable following acid hydrolysis studies. However, following alkali hydrolysis degradation of both compounds was observed. Furthermore metronidazole appeared to be stable following oxidative studies however ranitidine underwent complete degradation under these conditions. Both drugs were well resolved from the degradation products. The stability indicating chromatographic method has the necessary precision and accuracy for the simultaneous analysis of metronidazole and ranitidine in dosage forms.
- Full Text:
- Date Issued: 2014
Hsp90 binds directly to fibronectin (FN) and inhibition reduces the extracellular fibronectin matrix in breast cancer cells
- Hunter, Morgan C, O’Hagan, Kyle L, Kenyon, Amy, Dhanani, Karim C H, Prinsloo, Earl, Edkins, Adrienne L
- Authors: Hunter, Morgan C , O’Hagan, Kyle L , Kenyon, Amy , Dhanani, Karim C H , Prinsloo, Earl , Edkins, Adrienne L
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431143 , vital:72748 , xlink:href="https://doi.org/10.1371/journal.pone.0086842"
- Description: Heat shock protein 90 (Hsp90) has been identified in the extracellular space and has been shown to chaperone a finite number of extracellular proteins involved in cell migration and invasion. We used chemical cross-linking and immunoprecipitation followed by tandem mass spectrometry (MS/MS) to isolate a complex containing Hsp90 and the matrix protein fibronectin (FN) from breast cancer cells. Further analysis showed direct binding of Hsp90 to FN using an in vitro co-immunoprecipitation assay, a solid phase binding assay and surface plasmon resonance (SPR) spectroscopy. Confocal microscopy showed regions of co-localisation of Hsp90 and FN in breast cancer cell lines. Exogenous Hsp90β was shown to increase the formation of extracellular FN matrix in the Hs578T cell line, whilst knockdown or inhibition of Hsp90 led to a reduction in the levels of both soluble and insoluble FN and could be partially rescued by addition of exogenous Hsp90β. Treatment of cells with novobiocin led to internalization of FN into vesicles that were positive for the presence of the lysosomal marker, LAMP-1. Taken together, the direct interaction between FN and Hsp90, as well as the decreased levels of both soluble and insoluble FN upon Hsp90 inhibition or knockdown, suggested that FN may be a new client protein for Hsp90 and that Hsp90 was involved in FN matrix assembly and/or stability. The identification of FN as a putative client protein of Hsp90 suggests a role for Hsp90 in FN matrix stability, which is important for a number of fundamental cellular processes including embryogenesis, wound healing, cell migration and metastasis.
- Full Text:
- Date Issued: 2014
- Authors: Hunter, Morgan C , O’Hagan, Kyle L , Kenyon, Amy , Dhanani, Karim C H , Prinsloo, Earl , Edkins, Adrienne L
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431143 , vital:72748 , xlink:href="https://doi.org/10.1371/journal.pone.0086842"
- Description: Heat shock protein 90 (Hsp90) has been identified in the extracellular space and has been shown to chaperone a finite number of extracellular proteins involved in cell migration and invasion. We used chemical cross-linking and immunoprecipitation followed by tandem mass spectrometry (MS/MS) to isolate a complex containing Hsp90 and the matrix protein fibronectin (FN) from breast cancer cells. Further analysis showed direct binding of Hsp90 to FN using an in vitro co-immunoprecipitation assay, a solid phase binding assay and surface plasmon resonance (SPR) spectroscopy. Confocal microscopy showed regions of co-localisation of Hsp90 and FN in breast cancer cell lines. Exogenous Hsp90β was shown to increase the formation of extracellular FN matrix in the Hs578T cell line, whilst knockdown or inhibition of Hsp90 led to a reduction in the levels of both soluble and insoluble FN and could be partially rescued by addition of exogenous Hsp90β. Treatment of cells with novobiocin led to internalization of FN into vesicles that were positive for the presence of the lysosomal marker, LAMP-1. Taken together, the direct interaction between FN and Hsp90, as well as the decreased levels of both soluble and insoluble FN upon Hsp90 inhibition or knockdown, suggested that FN may be a new client protein for Hsp90 and that Hsp90 was involved in FN matrix assembly and/or stability. The identification of FN as a putative client protein of Hsp90 suggests a role for Hsp90 in FN matrix stability, which is important for a number of fundamental cellular processes including embryogenesis, wound healing, cell migration and metastasis.
- Full Text:
- Date Issued: 2014
Hsp90 binds directly to fibronectin (FN) and inhibition reduces the extracellular fibronectin matrix in breast cancer cells:
- Hunter, Morgan C, O’Hagan, Kyle L, Kenyon, Amy, Dhanani, Karim C H, Prinsloo, Earl, Edkins, Adrienne L
- Authors: Hunter, Morgan C , O’Hagan, Kyle L , Kenyon, Amy , Dhanani, Karim C H , Prinsloo, Earl , Edkins, Adrienne L
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164841 , vital:41177 , DOI: 10.1371/journal.pone.0086842
- Description: Heat shock protein 90 (Hsp90) has been identified in the extracellular space and has been shown to chaperone a finite number of extracellular proteins involved in cell migration and invasion. We used chemical cross-linking and immunoprecipitation followed by tandem mass spectrometry (MS/MS) to isolate a complex containing Hsp90 and the matrix protein fibronectin (FN) from breast cancer cells.
- Full Text:
- Date Issued: 2014
- Authors: Hunter, Morgan C , O’Hagan, Kyle L , Kenyon, Amy , Dhanani, Karim C H , Prinsloo, Earl , Edkins, Adrienne L
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164841 , vital:41177 , DOI: 10.1371/journal.pone.0086842
- Description: Heat shock protein 90 (Hsp90) has been identified in the extracellular space and has been shown to chaperone a finite number of extracellular proteins involved in cell migration and invasion. We used chemical cross-linking and immunoprecipitation followed by tandem mass spectrometry (MS/MS) to isolate a complex containing Hsp90 and the matrix protein fibronectin (FN) from breast cancer cells.
- Full Text:
- Date Issued: 2014
Human perception of the measurement of a network attack taxonomy in near real-time
- Van Heerden, Renier, Malan, Mercia M, Mouton, Francois, Irwin, Barry V W
- Authors: Van Heerden, Renier , Malan, Mercia M , Mouton, Francois , Irwin, Barry V W
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429924 , vital:72652 , https://doi.org/10.1007/978-3-662-44208-1_23
- Description: This paper investigates how the measurement of a network attack taxonomy can be related to human perception. Network attacks do not have a time limitation, but the earlier its detected, the more damage can be prevented and the more preventative actions can be taken. This paper evaluate how elements of network attacks can be measured in near real-time(60 seconds). The taxonomy we use was developed by van Heerden et al (2012) with over 100 classes. These classes present the attack and defenders point of view. The degree to which each class can be quantified or measured is determined by investigating the accuracy of various assessment methods. We classify each class as either defined, high, low or not quantifiable. For example, it may not be possible to determine the instigator of an attack (Aggressor), but only that the attack has been launched by a Hacker (Actor). Some classes can only be quantified with a low confidence or not at all in a sort (near real-time) time. The IP address of an attack can easily be faked thus reducing the confidence in the information obtained from it, and thus determining the origin of an attack with a low confidence. This determination itself is subjective. All the evaluations of the classes in this paper is subjective, but due to the very basic grouping (High, Low or Not Quantifiable) a subjective value can be used. The complexity of the taxonomy can be significantly reduced if classes with only a high perceptive accuracy is used.
- Full Text:
- Date Issued: 2014
- Authors: Van Heerden, Renier , Malan, Mercia M , Mouton, Francois , Irwin, Barry V W
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429924 , vital:72652 , https://doi.org/10.1007/978-3-662-44208-1_23
- Description: This paper investigates how the measurement of a network attack taxonomy can be related to human perception. Network attacks do not have a time limitation, but the earlier its detected, the more damage can be prevented and the more preventative actions can be taken. This paper evaluate how elements of network attacks can be measured in near real-time(60 seconds). The taxonomy we use was developed by van Heerden et al (2012) with over 100 classes. These classes present the attack and defenders point of view. The degree to which each class can be quantified or measured is determined by investigating the accuracy of various assessment methods. We classify each class as either defined, high, low or not quantifiable. For example, it may not be possible to determine the instigator of an attack (Aggressor), but only that the attack has been launched by a Hacker (Actor). Some classes can only be quantified with a low confidence or not at all in a sort (near real-time) time. The IP address of an attack can easily be faked thus reducing the confidence in the information obtained from it, and thus determining the origin of an attack with a low confidence. This determination itself is subjective. All the evaluations of the classes in this paper is subjective, but due to the very basic grouping (High, Low or Not Quantifiable) a subjective value can be used. The complexity of the taxonomy can be significantly reduced if classes with only a high perceptive accuracy is used.
- Full Text:
- Date Issued: 2014
Hyperbenthic and pelagic predators regulate alternate key planktonic copepods in shallow temperate estuaries
- Wasserman, Ryan J, Vink, Tim J F, Kramer, Rachel, Froneman, P William
- Authors: Wasserman, Ryan J , Vink, Tim J F , Kramer, Rachel , Froneman, P William
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68224 , vital:29220 , https://doi.org/10.1071/MF13233
- Description: Publisher version , Although predation has been identified as an important community driver, the role of predator diversity in structuring estuarine zooplankton has not been assessed. As such, we investigated the effects of two different zooplanktivorous fish species on the estuarine zooplankton community during a 12-day mesocosm study. Three experimental treatments were established, whereby natural zooplankton communities were subject to either (1) no predatory pressure, (2) predation by a pelagic predator (Monodactylus falciformis) or (3) predation by a hyper-benthic predator (Glossogobius callidus). The pelagic feeding M. falciformis fed largely on the numerically dominant mid-water copepod species, Paracartia longipatella. In contrast, the hyper-benthic fish had a greater predatory impact on the less numerically dominant copepod, Pseudodiaptomus hessei, which demonstrates strong diel vertical migration. Variations in prey-population regulation are ascribed to the distinct behavioural differences of the predators, and mediated by the differences in behaviour of the copepod species.
- Full Text: false
- Date Issued: 2014
- Authors: Wasserman, Ryan J , Vink, Tim J F , Kramer, Rachel , Froneman, P William
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68224 , vital:29220 , https://doi.org/10.1071/MF13233
- Description: Publisher version , Although predation has been identified as an important community driver, the role of predator diversity in structuring estuarine zooplankton has not been assessed. As such, we investigated the effects of two different zooplanktivorous fish species on the estuarine zooplankton community during a 12-day mesocosm study. Three experimental treatments were established, whereby natural zooplankton communities were subject to either (1) no predatory pressure, (2) predation by a pelagic predator (Monodactylus falciformis) or (3) predation by a hyper-benthic predator (Glossogobius callidus). The pelagic feeding M. falciformis fed largely on the numerically dominant mid-water copepod species, Paracartia longipatella. In contrast, the hyper-benthic fish had a greater predatory impact on the less numerically dominant copepod, Pseudodiaptomus hessei, which demonstrates strong diel vertical migration. Variations in prey-population regulation are ascribed to the distinct behavioural differences of the predators, and mediated by the differences in behaviour of the copepod species.
- Full Text: false
- Date Issued: 2014
Imagining Civil Society in Zimbabwe and ‘Most of the World’:
- Authors: Helliker, Kirk D
- Date: 2014
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/144802 , vital:38380 , ISBN 9781461482628 , DOI: 10.1007/978-1-4614-8262-8_11
- Description: This chapter re-visits the notion of civil society in what Partha Chatterjee (The Politics of the Governed, 2004) calls ‘most of the world’ (beyond the capitalist metropoles) and, in doing so, uses Zimbabwe (and Africa more broadly) as an entry point into the literature on civil society. This chapter consists of four main sections. First, I discuss literature on civil society in Africa which, in the main, dichotomises civil society and the state empirically without any sustained theoretical reflections. Second, I provide an overview of Zimbabwean society and politics over the past decade and the ensuing debate, which in many ways produces a Manichean dualism whereby civil society is equated with progression and the state with regression. Third, I locate this conceptualisation of civil society within the broader international literature on civil society. These three sections, as a whole, highlight slippages in defining and understanding civil society: between civil society as a set of empirically identifiable organisational formations and civil society as a social space marked by civil liberties and voluntary arrangements in bourgeois society. Finally, I reimagine civil society in relation to ‘most of the world’.
- Full Text:
- Date Issued: 2014
- Authors: Helliker, Kirk D
- Date: 2014
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/144802 , vital:38380 , ISBN 9781461482628 , DOI: 10.1007/978-1-4614-8262-8_11
- Description: This chapter re-visits the notion of civil society in what Partha Chatterjee (The Politics of the Governed, 2004) calls ‘most of the world’ (beyond the capitalist metropoles) and, in doing so, uses Zimbabwe (and Africa more broadly) as an entry point into the literature on civil society. This chapter consists of four main sections. First, I discuss literature on civil society in Africa which, in the main, dichotomises civil society and the state empirically without any sustained theoretical reflections. Second, I provide an overview of Zimbabwean society and politics over the past decade and the ensuing debate, which in many ways produces a Manichean dualism whereby civil society is equated with progression and the state with regression. Third, I locate this conceptualisation of civil society within the broader international literature on civil society. These three sections, as a whole, highlight slippages in defining and understanding civil society: between civil society as a set of empirically identifiable organisational formations and civil society as a social space marked by civil liberties and voluntary arrangements in bourgeois society. Finally, I reimagine civil society in relation to ‘most of the world’.
- Full Text:
- Date Issued: 2014
Improved l-cysteine electrocatalysis through a sequential drop dry technique using multi-walled carbon nanotubes and cobalt tetraaminophthalocyanine conjugates
- Nyoni, Stephen, Mugadza, Tawanda, Nyokong, Tebello
- Authors: Nyoni, Stephen , Mugadza, Tawanda , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193813 , vital:45398 , xlink:href="https://doi.org/10.1016/j.electacta.2013.10.023"
- Description: Voltammetry, chronoamperometry, scanning electrochemical microscopy and electrochemical impedance spectroscopy methods are used for characterization of a glassy carbon electrode modified with multi-walled carbon nanotubes (MWCNTs)–cobalt tetraaminophthalocyanine (CoTAPc) mixture or sequential drop dry modification technique whereby the MWCNTs are first placed on to the electrode followed by CoTAPc. The sequential drop dry CoTAPc–MWCNTs modified surface gave better catalytic responses with a catalytic rate constant of 2.2 × 105 M−1 s−1, apparent electron transfer rate constant of 0.073 cm s−1, and a limit of detection of 2.8 × 10−7 M. Scanning electrochemical microscopy (SECM) surface characterization (topography and reactivity) further gave proof the better catalytic perfomance of the sequential drop dry CoTAPc–MWCNTs modified surface.
- Full Text:
- Date Issued: 2014
- Authors: Nyoni, Stephen , Mugadza, Tawanda , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193813 , vital:45398 , xlink:href="https://doi.org/10.1016/j.electacta.2013.10.023"
- Description: Voltammetry, chronoamperometry, scanning electrochemical microscopy and electrochemical impedance spectroscopy methods are used for characterization of a glassy carbon electrode modified with multi-walled carbon nanotubes (MWCNTs)–cobalt tetraaminophthalocyanine (CoTAPc) mixture or sequential drop dry modification technique whereby the MWCNTs are first placed on to the electrode followed by CoTAPc. The sequential drop dry CoTAPc–MWCNTs modified surface gave better catalytic responses with a catalytic rate constant of 2.2 × 105 M−1 s−1, apparent electron transfer rate constant of 0.073 cm s−1, and a limit of detection of 2.8 × 10−7 M. Scanning electrochemical microscopy (SECM) surface characterization (topography and reactivity) further gave proof the better catalytic perfomance of the sequential drop dry CoTAPc–MWCNTs modified surface.
- Full Text:
- Date Issued: 2014
Incorporating surrogate species and seascape connectivity to improve marine conservation outcomes
- Olds, Andrew D, Connolly, Rod M, Pitt, Kylie A, Maxwell, Paul S, Aswani, Shankar, Albert, Simon
- Authors: Olds, Andrew D , Connolly, Rod M , Pitt, Kylie A , Maxwell, Paul S , Aswani, Shankar , Albert, Simon
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124722 , vital:35655 , https://doi.10.1111/cobi.12242
- Description: Conservation focuses on maintaining biodiversity and ecosystem functioning, but gaps in our knowledge of species biology and ecological processes often impede progress. For this reason, focal species and habitats are used as surrogates for multispecies conservation, but species-based approaches are not widely adopted in marine ecosystems. Reserves in the Solomon Islands were designed on the basis of local ecological knowledge to conserve bumphead parrotfish (Bolbometopon muricatum) and to protect food security and ecosystem functioning. Bumphead parrotfish are an iconic threatened species and may be a useful surrogate for multispecies conservation. They move across tropical seascapes throughout their life history, in a pattern of habitat use that is shared with many other species. We examined their value as a conservation surrogate and assessed the importance of seascape connectivity (i.e., the physical connectedness of patches in the seascape) among reefs, mangroves, and seagrass to marine reserve performance. Reserves were designed for bumphead parrotfish, but also enhanced the abundance of other species. Integration of local ecological knowledge and seascape connectivity enhanced the abundance of 17 other harvested fish species in local reserves. This result has important implications for ecosystem functioning and local villagers because many of these species perform important ecological processes and provide the foundation for extensive subsistence fisheries. Our findings suggest greater success in maintaining and restoring marine ecosystems may be achieved when they are managed to conserve surrogate species and preserve functional seascape connections.
- Full Text:
- Date Issued: 2014
- Authors: Olds, Andrew D , Connolly, Rod M , Pitt, Kylie A , Maxwell, Paul S , Aswani, Shankar , Albert, Simon
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124722 , vital:35655 , https://doi.10.1111/cobi.12242
- Description: Conservation focuses on maintaining biodiversity and ecosystem functioning, but gaps in our knowledge of species biology and ecological processes often impede progress. For this reason, focal species and habitats are used as surrogates for multispecies conservation, but species-based approaches are not widely adopted in marine ecosystems. Reserves in the Solomon Islands were designed on the basis of local ecological knowledge to conserve bumphead parrotfish (Bolbometopon muricatum) and to protect food security and ecosystem functioning. Bumphead parrotfish are an iconic threatened species and may be a useful surrogate for multispecies conservation. They move across tropical seascapes throughout their life history, in a pattern of habitat use that is shared with many other species. We examined their value as a conservation surrogate and assessed the importance of seascape connectivity (i.e., the physical connectedness of patches in the seascape) among reefs, mangroves, and seagrass to marine reserve performance. Reserves were designed for bumphead parrotfish, but also enhanced the abundance of other species. Integration of local ecological knowledge and seascape connectivity enhanced the abundance of 17 other harvested fish species in local reserves. This result has important implications for ecosystem functioning and local villagers because many of these species perform important ecological processes and provide the foundation for extensive subsistence fisheries. Our findings suggest greater success in maintaining and restoring marine ecosystems may be achieved when they are managed to conserve surrogate species and preserve functional seascape connections.
- Full Text:
- Date Issued: 2014
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