The importance of long-term post-release studies in classical biological control: Insect–plant monitoring and public awareness of water hyacinth management (Pontederia crassipes) in Dique Los Sauces, Argentina
- Faltlhauser, Ana C, Jiménez, Nadia L, Righetti, Tomas, Visintin, Andrés M, Torrens, Javier, Salinas, Nicolás A, Mc Kay, Fernando, Hill, Martin P, Cordo, Hugo A, Sosa, Alejandro J
- Authors: Faltlhauser, Ana C , Jiménez, Nadia L , Righetti, Tomas , Visintin, Andrés M , Torrens, Javier , Salinas, Nicolás A , Mc Kay, Fernando , Hill, Martin P , Cordo, Hugo A , Sosa, Alejandro J
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424828 , vital:72187 , xlink:href="https://doi.org/10.1111/eea.13355"
- Description: Several components of classical biological control (CBC) programmes are necessary to assess the success of the management strategy (e.g., post-release monitoring) and also help prevent reintroductions or resurgences of invasive species (e.g., public awareness). Water hyacinth, Pontederia (= Eichhornia) crassipes (Mart.) Solms (Pontederiaceae) is an aquatic plant naturally distributed in the north-eastern region of the Del Plata basin in Argentina. In the 1960s it was introduced into the Dique Los Sauces reservoir located outside of its native range in La Rioja Province, in western Argentina, where it became invasive. The natural enemy, Neochetina bruchi Hustache (Coleoptera: Curculionidae), was intentionally introduced in 1974 to control the weed. To assess the success of this CBC programme, a long-term post-release study was conducted. Between 1965 and 2023, we monitored plant coverage, estimated N. bruchi densities, and quantified the associated damage by reanalysing previously published data and incorporating new sampling. We also conducted an online survey to analyse public knowledge and perception about this programme. Water hyacinth coverage fluctuated from its first record in 1965 (maximum coverage 90%) until the control of germinated plants (coverage 0%) in 2018. The plant decline was accompanied by an increase in the weevil population. In our survey, out of 325 respondents only a small group of mostly middle-aged and elderly people knew that the restoration had been achieved through a management strategy and even fewer were aware of the biocontrol approach taken. Respondents who had a positive approach to biological control were more aware of the management plan than respondents who had neutral or negative opinions. Neochetina bruchi has played a key factor in the control of P. crassipes. The intrinsic dynamics of these populations, the dormant seed bank, and the lack of public awareness support the need for long post-release evaluations including outreach campaigns to make a sustainable successful management programme.
- Full Text:
- Authors: Faltlhauser, Ana C , Jiménez, Nadia L , Righetti, Tomas , Visintin, Andrés M , Torrens, Javier , Salinas, Nicolás A , Mc Kay, Fernando , Hill, Martin P , Cordo, Hugo A , Sosa, Alejandro J
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424828 , vital:72187 , xlink:href="https://doi.org/10.1111/eea.13355"
- Description: Several components of classical biological control (CBC) programmes are necessary to assess the success of the management strategy (e.g., post-release monitoring) and also help prevent reintroductions or resurgences of invasive species (e.g., public awareness). Water hyacinth, Pontederia (= Eichhornia) crassipes (Mart.) Solms (Pontederiaceae) is an aquatic plant naturally distributed in the north-eastern region of the Del Plata basin in Argentina. In the 1960s it was introduced into the Dique Los Sauces reservoir located outside of its native range in La Rioja Province, in western Argentina, where it became invasive. The natural enemy, Neochetina bruchi Hustache (Coleoptera: Curculionidae), was intentionally introduced in 1974 to control the weed. To assess the success of this CBC programme, a long-term post-release study was conducted. Between 1965 and 2023, we monitored plant coverage, estimated N. bruchi densities, and quantified the associated damage by reanalysing previously published data and incorporating new sampling. We also conducted an online survey to analyse public knowledge and perception about this programme. Water hyacinth coverage fluctuated from its first record in 1965 (maximum coverage 90%) until the control of germinated plants (coverage 0%) in 2018. The plant decline was accompanied by an increase in the weevil population. In our survey, out of 325 respondents only a small group of mostly middle-aged and elderly people knew that the restoration had been achieved through a management strategy and even fewer were aware of the biocontrol approach taken. Respondents who had a positive approach to biological control were more aware of the management plan than respondents who had neutral or negative opinions. Neochetina bruchi has played a key factor in the control of P. crassipes. The intrinsic dynamics of these populations, the dormant seed bank, and the lack of public awareness support the need for long post-release evaluations including outreach campaigns to make a sustainable successful management programme.
- Full Text:
Shifting contexts: contemporary South African art in changing times
- Authors: Ntombela, N
- Date: 2019
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/146200 , vital:38504 , ISBN 9781869143398 , https://books.google.co.za/books?id=xZlAjySD5-cCandq=Tribing+and+Untribing+the+Archive:+Identity+and+the+Material+Record+in+Southern+KwaZulu-Natal+in+the+Late+Independent+and+Colonial+Periodsdq=Tribing+and+Untribing+the+Archive:+Identity+and+the+Material+Record+in+Southern+KwaZulu-Natal+in+the+Late+Independent+and+Colonial+Periodsl=ensa=Xved=0ahUKEwjJ3oOGgcDpAhVuURUIHQyoAnIQ6AEIJzAA
- Description: Book abstract. The pernicious combination of tribe and tradition continues to tether modern South Africans to ideas about the region's remote past as primitive, timeless, and unchanging. Any hunger for knowledge or understanding of the past before European colonialism remains to a significant degree unsated in the face of a narrowly prescribed archive and repugnant, but insidiously resilient, stereotypes. These volumes track how the domain of the tribal and traditional came to be sharply distinguished from modernity, how it was denied a changing history and an archive, and was endowed instead with a timeless culture. They also offer strategies for engaging with the materials differently-from the interventions effected in contemporary artworks to the inserting of nameless, timeless objects of material culture into histories of individualized and politicized experience. The two volume set make this archive of material culture visible as an archival resource. They also seek to spring the identity trap, releasing the material from pre-assigned identity positions as tribal into settings that enable them to be used as resources for thinking critically about identity.
- Full Text:
- Authors: Ntombela, N
- Date: 2019
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/146200 , vital:38504 , ISBN 9781869143398 , https://books.google.co.za/books?id=xZlAjySD5-cCandq=Tribing+and+Untribing+the+Archive:+Identity+and+the+Material+Record+in+Southern+KwaZulu-Natal+in+the+Late+Independent+and+Colonial+Periodsdq=Tribing+and+Untribing+the+Archive:+Identity+and+the+Material+Record+in+Southern+KwaZulu-Natal+in+the+Late+Independent+and+Colonial+Periodsl=ensa=Xved=0ahUKEwjJ3oOGgcDpAhVuURUIHQyoAnIQ6AEIJzAA
- Description: Book abstract. The pernicious combination of tribe and tradition continues to tether modern South Africans to ideas about the region's remote past as primitive, timeless, and unchanging. Any hunger for knowledge or understanding of the past before European colonialism remains to a significant degree unsated in the face of a narrowly prescribed archive and repugnant, but insidiously resilient, stereotypes. These volumes track how the domain of the tribal and traditional came to be sharply distinguished from modernity, how it was denied a changing history and an archive, and was endowed instead with a timeless culture. They also offer strategies for engaging with the materials differently-from the interventions effected in contemporary artworks to the inserting of nameless, timeless objects of material culture into histories of individualized and politicized experience. The two volume set make this archive of material culture visible as an archival resource. They also seek to spring the identity trap, releasing the material from pre-assigned identity positions as tribal into settings that enable them to be used as resources for thinking critically about identity.
- Full Text:
Colonised minds?: post-development theory and the desirability of development in Africa
- Authors: Matthews, Sally
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142213 , vital:38059 , DOI: 10.1080/01436597.2017.1279540
- Description: While post-development theory is very concerned with the ways in which development has impacted upon the countries of the Global South, there has been relatively little written on post-development theory from an African perspective. This paper identifies some of the ways in which post-development theory fails to adequately understand the African experience of development. In particular, I explore the difficulty that post-development theory confronts when faced with the continued desire on the part of many people in Africa for development.
- Full Text:
- Authors: Matthews, Sally
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142213 , vital:38059 , DOI: 10.1080/01436597.2017.1279540
- Description: While post-development theory is very concerned with the ways in which development has impacted upon the countries of the Global South, there has been relatively little written on post-development theory from an African perspective. This paper identifies some of the ways in which post-development theory fails to adequately understand the African experience of development. In particular, I explore the difficulty that post-development theory confronts when faced with the continued desire on the part of many people in Africa for development.
- Full Text:
Counting on demographic equity to transform institutional cultures at historically white South African universities?:
- Booi, Masixole, Vincent, Louise, Liccardo, Sabrina
- Authors: Booi, Masixole , Vincent, Louise , Liccardo, Sabrina
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141946 , vital:38018 , DOI: 10.1080/07294360.2017.1289155
- Description: The post-apartheid higher education transformation project is faced with the challenge of recruiting and retaining black academics and other senior staff. But when we shift the focus from participation rates to equality–inequality within historically white universities (HWUs), then the discourse changes from demographic equity and redress to institutional culture and diversity. HWUs invoke the need to maintain their position as leading higher education institutions globally, and notions of ‘quality’ and ‘excellence’ have emerged as discursive practices, which serve to perpetuate exclusion. The question then arises as to which forms of capital comprise the Gold Standard at HWUs? Several South African universities have responded to the challenge of recruiting and retaining black academics by initiating programmes for the ‘accelerated development’ of these candidates.
- Full Text:
- Authors: Booi, Masixole , Vincent, Louise , Liccardo, Sabrina
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141946 , vital:38018 , DOI: 10.1080/07294360.2017.1289155
- Description: The post-apartheid higher education transformation project is faced with the challenge of recruiting and retaining black academics and other senior staff. But when we shift the focus from participation rates to equality–inequality within historically white universities (HWUs), then the discourse changes from demographic equity and redress to institutional culture and diversity. HWUs invoke the need to maintain their position as leading higher education institutions globally, and notions of ‘quality’ and ‘excellence’ have emerged as discursive practices, which serve to perpetuate exclusion. The question then arises as to which forms of capital comprise the Gold Standard at HWUs? Several South African universities have responded to the challenge of recruiting and retaining black academics by initiating programmes for the ‘accelerated development’ of these candidates.
- Full Text:
Decoupled reciprocal subsidies of biomass and fatty acids in fluxes of invertebrates between a temperate river and the adjacent land:
- Moyo, Sydney, Chari, Lenin D, Villet, Martin H, Richoux, Nicole B
- Authors: Moyo, Sydney , Chari, Lenin D , Villet, Martin H , Richoux, Nicole B
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140843 , vital:37923 , DOI: 10.1007/s00027-017-0529-0
- Description: Streams and riparian areas are tightly coupled through reciprocal trophic subsidies, and there is evidence that these subsidies affect consumers in connected ecosystems. Most studies of subsidies consider only their quantity and not their quality. We determined the bidirectional exchange of organisms between the Kowie River and its riparian zone in South Africa using floating pyramidal traps (to measure insect emergence) and pan traps (to capture infalling invertebrates).
- Full Text:
- Authors: Moyo, Sydney , Chari, Lenin D , Villet, Martin H , Richoux, Nicole B
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140843 , vital:37923 , DOI: 10.1007/s00027-017-0529-0
- Description: Streams and riparian areas are tightly coupled through reciprocal trophic subsidies, and there is evidence that these subsidies affect consumers in connected ecosystems. Most studies of subsidies consider only their quantity and not their quality. We determined the bidirectional exchange of organisms between the Kowie River and its riparian zone in South Africa using floating pyramidal traps (to measure insect emergence) and pan traps (to capture infalling invertebrates).
- Full Text:
Forensic entomotoxicology revisited: towards professional standardisation of study designs
- da Silva, Erica I T, Wilhelmi, Brendan S, Villet, Martin H
- Authors: da Silva, Erica I T , Wilhelmi, Brendan S , Villet, Martin H
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140819 , vital:37921 , DOI: 10.1007/s00414-017-1603-9
- Description: Forensic entomotoxicology is the use of insects as evidence of whether a toxicant is present in an environment such as a corpse, river or landscape. The earliest overtly forensic study was published in 1977, and since then, at least 63 papers have been published, most of them focused on the detection of toxicants in insects or on effects of toxicants on diverse insect indicator taxa. A comprehensive review of the published literature revealed various inconsistencies between studies that could be addressed by introducing standard protocols for such studies. These protocols could include selecting widespread and common model organisms (such as Lucilia sericata, Calliphora vicina, Chrysomya megacephala and Dermestes maculatus) and model toxicants (e.g. morphine and amitriptyline) to build up comparative databases; developing a standard matrix for use as a feeding substrate; setting guidelines for statistically adequate sample sizes; and deploying more sophisticated analytical methods from the general field of toxicology.
- Full Text:
- Authors: da Silva, Erica I T , Wilhelmi, Brendan S , Villet, Martin H
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140819 , vital:37921 , DOI: 10.1007/s00414-017-1603-9
- Description: Forensic entomotoxicology is the use of insects as evidence of whether a toxicant is present in an environment such as a corpse, river or landscape. The earliest overtly forensic study was published in 1977, and since then, at least 63 papers have been published, most of them focused on the detection of toxicants in insects or on effects of toxicants on diverse insect indicator taxa. A comprehensive review of the published literature revealed various inconsistencies between studies that could be addressed by introducing standard protocols for such studies. These protocols could include selecting widespread and common model organisms (such as Lucilia sericata, Calliphora vicina, Chrysomya megacephala and Dermestes maculatus) and model toxicants (e.g. morphine and amitriptyline) to build up comparative databases; developing a standard matrix for use as a feeding substrate; setting guidelines for statistically adequate sample sizes; and deploying more sophisticated analytical methods from the general field of toxicology.
- Full Text:
MD-TASK: a software suite for analyzing molecular dynamics trajectories
- Brown, David K, Penkler, David L, Amamuddy, Olivier S, Ross, Caroline J, Atilgan, Ali R, Atilgan, Canan, Tastan Bishop, Özlem
- Authors: Brown, David K , Penkler, David L , Amamuddy, Olivier S , Ross, Caroline J , Atilgan, Ali R , Atilgan, Canan , Tastan Bishop, Özlem
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125138 , vital:35735 , https://doi.10.1093/bioinformatics/btx349
- Description: Molecular dynamics (MD) determines the physical motions of atoms of a biological macromolecule in a cell-like environment and is an important method in structural bioinformatics. Traditionally, measurements such as root mean square deviation, root mean square fluctuation, radius of gyration, and various energy measures have been used to analyze MD simulations. Here, we present MD-TASK, a novel software suite that employs graph theory techniques, perturbation response scanning, and dynamic cross-correlation to provide unique ways for analyzing MD trajectories.
- Full Text:
- Authors: Brown, David K , Penkler, David L , Amamuddy, Olivier S , Ross, Caroline J , Atilgan, Ali R , Atilgan, Canan , Tastan Bishop, Özlem
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125138 , vital:35735 , https://doi.10.1093/bioinformatics/btx349
- Description: Molecular dynamics (MD) determines the physical motions of atoms of a biological macromolecule in a cell-like environment and is an important method in structural bioinformatics. Traditionally, measurements such as root mean square deviation, root mean square fluctuation, radius of gyration, and various energy measures have been used to analyze MD simulations. Here, we present MD-TASK, a novel software suite that employs graph theory techniques, perturbation response scanning, and dynamic cross-correlation to provide unique ways for analyzing MD trajectories.
- Full Text:
Pessimistic assessment of white shark population status in South Africa: comment on Andreotti et al.(2016)
- Irion, Dylan T, Noble, Leslie R, Kock, Alison A, Gennari, Enrico, Dicken, Matthew L, Hewitt, Adrian M, Towner, Alison V, Booth, Anthony J, Smale, Malcolm J, Cliff, Geremy
- Authors: Irion, Dylan T , Noble, Leslie R , Kock, Alison A , Gennari, Enrico , Dicken, Matthew L , Hewitt, Adrian M , Towner, Alison V , Booth, Anthony J , Smale, Malcolm J , Cliff, Geremy
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:35799 , https://doi.10.3354/meps12283
- Description: Andreotti et al. (2016; Mar Ecol Prog Ser 552:241−253) estimate an abundance (N) of 438 white sharks Carcharodon carcharias and a contemporary effective population size (CNe) of 333 individuals along the South African coast. N was estimated by using a mark-recapture analysis of photographic identification records from a single aggregation site (Gansbaai). CNe was calculated based on the levels of pairwise linkage disequilibrium of genetic material collected from 4 aggregation sites across approximately 965 km of South African coastline. However, due to the complex stock structure of white sharks and the model assumptions made by Andreotti et al. (2016), the conclusions drawn cannot be supported by their methods and data.
- Full Text:
- Authors: Irion, Dylan T , Noble, Leslie R , Kock, Alison A , Gennari, Enrico , Dicken, Matthew L , Hewitt, Adrian M , Towner, Alison V , Booth, Anthony J , Smale, Malcolm J , Cliff, Geremy
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:35799 , https://doi.10.3354/meps12283
- Description: Andreotti et al. (2016; Mar Ecol Prog Ser 552:241−253) estimate an abundance (N) of 438 white sharks Carcharodon carcharias and a contemporary effective population size (CNe) of 333 individuals along the South African coast. N was estimated by using a mark-recapture analysis of photographic identification records from a single aggregation site (Gansbaai). CNe was calculated based on the levels of pairwise linkage disequilibrium of genetic material collected from 4 aggregation sites across approximately 965 km of South African coastline. However, due to the complex stock structure of white sharks and the model assumptions made by Andreotti et al. (2016), the conclusions drawn cannot be supported by their methods and data.
- Full Text:
Rhodes University Graduation Ceremony 2017
- Authors: Rhodes University
- Date: 2017
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/58067 , vital:27061
- Description: 2017 Graduation Ceremony, Umsitho Wothweso-Zidanga, Gradeplegtigheid [at] 1820 Settlers National Monument, Thursday, 20 April until Saturday, 22 April 2017.
- Full Text:
- Authors: Rhodes University
- Date: 2017
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/58067 , vital:27061
- Description: 2017 Graduation Ceremony, Umsitho Wothweso-Zidanga, Gradeplegtigheid [at] 1820 Settlers National Monument, Thursday, 20 April until Saturday, 22 April 2017.
- Full Text:
Synthesis, characterisation and evaluation of benzoxaborole-based hybrids as antiplasmodial agents
- Authors: Gumbo, Maureen
- Date: 2017
- Subjects: Malaria Chemotherapy , Antimalarials , Boron compounds , Drug resistance , Plasmodium falciparum , Drug development
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/59193 , vital:27456
- Description: Malaria is a mosquito-borne disease, which continues to pose a threat to the entire humanity. About 40% of the world population is estimated to be at risk of infections by malaria. Despite efforts undertaken by scientific community, government entities and international organizations, malaria is still rampant. The major problem is drug resistance, where the Plasmodium spp have over the past decades developed drug resistance against available drugs. In order to counter this problem, novel antimalarial drugs that are efficacious and with novel mode of action are of great necessity. Benzoxaborole derivatives have been shown to exhibit promising antimalarial activity against Plasmodium falciparum strains. Previous studies reported on the compounds such as 6-(2- (alkoxycarbonyl)pyrazinyl-5-oxy)-1,3-dihydro-1-hydroxy-2,1-benzoxaboroles, which showed good antimalarial activity against both W7 and 3D7 strains without significant toxicity. On the other hand, chloroquine (CQ) and cinnamic acids have a wide variety of biological activity including antimalarial activity. Herein, a hybridisation strategy was employed to synthesise new CQ-benzoxaborole and cinnamoyl-benzoxaborole hybrids. CQ-Benzoxaborole 2.12a-c and cinnamoylbenzoxaborole 2.11a-g hydrid molecules were synthesised in low to good yields. Their structural identities were confirmed using conventional spectroscopic techniques (1H and 13C NMR, and mass spectrometry). CQ-benzoxaborole compounds, however, showed instability, and only 2.12b was used for in vitro biological assay and showed activity comparable to CQ. Furthermore, in vitro biological assay revealed that compounds 2.11a-g poorly inhibited the growth of P. falciparum parasites. Interestingly, these compounds, however, exhibited satisfactory activity against Trypanosoma brucei with IC50 = 0.052 μM for compound 2.11g. The cell cytotoxicity assay of all final compounds confirmed that all CQ-benzoxaborole 2.12b and cinnamoyl-benzoxaborole 2.11a-g hybrids were non-toxic against HeLa cell lines. However, efforts to further expand the structure-activity relationship (SAR) of CQbenzoxaborole by increasing the length of the linker with one extra carbon (Scheme 2.10) were not possible as an important precursor 6-formylbenzoxaborole 2.29 could not be synthesized in sufficient yields. , Thesis (MSc) -- Faculty of Faculty of Science, Chemistry, 2017
- Full Text:
- Authors: Gumbo, Maureen
- Date: 2017
- Subjects: Malaria Chemotherapy , Antimalarials , Boron compounds , Drug resistance , Plasmodium falciparum , Drug development
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/59193 , vital:27456
- Description: Malaria is a mosquito-borne disease, which continues to pose a threat to the entire humanity. About 40% of the world population is estimated to be at risk of infections by malaria. Despite efforts undertaken by scientific community, government entities and international organizations, malaria is still rampant. The major problem is drug resistance, where the Plasmodium spp have over the past decades developed drug resistance against available drugs. In order to counter this problem, novel antimalarial drugs that are efficacious and with novel mode of action are of great necessity. Benzoxaborole derivatives have been shown to exhibit promising antimalarial activity against Plasmodium falciparum strains. Previous studies reported on the compounds such as 6-(2- (alkoxycarbonyl)pyrazinyl-5-oxy)-1,3-dihydro-1-hydroxy-2,1-benzoxaboroles, which showed good antimalarial activity against both W7 and 3D7 strains without significant toxicity. On the other hand, chloroquine (CQ) and cinnamic acids have a wide variety of biological activity including antimalarial activity. Herein, a hybridisation strategy was employed to synthesise new CQ-benzoxaborole and cinnamoyl-benzoxaborole hybrids. CQ-Benzoxaborole 2.12a-c and cinnamoylbenzoxaborole 2.11a-g hydrid molecules were synthesised in low to good yields. Their structural identities were confirmed using conventional spectroscopic techniques (1H and 13C NMR, and mass spectrometry). CQ-benzoxaborole compounds, however, showed instability, and only 2.12b was used for in vitro biological assay and showed activity comparable to CQ. Furthermore, in vitro biological assay revealed that compounds 2.11a-g poorly inhibited the growth of P. falciparum parasites. Interestingly, these compounds, however, exhibited satisfactory activity against Trypanosoma brucei with IC50 = 0.052 μM for compound 2.11g. The cell cytotoxicity assay of all final compounds confirmed that all CQ-benzoxaborole 2.12b and cinnamoyl-benzoxaborole 2.11a-g hybrids were non-toxic against HeLa cell lines. However, efforts to further expand the structure-activity relationship (SAR) of CQbenzoxaborole by increasing the length of the linker with one extra carbon (Scheme 2.10) were not possible as an important precursor 6-formylbenzoxaborole 2.29 could not be synthesized in sufficient yields. , Thesis (MSc) -- Faculty of Faculty of Science, Chemistry, 2017
- Full Text:
"Let loose in the unthinkable unspeakable": waiting and alterity in Samuel Beckett's trilogy
- Authors: Marais, Jessica
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3917 , vital:20557
- Description: In this thesis, I examine the interrelated roles of waiting and alterity in Samuel Beckett's trilogy of novels: Molloy, Malone Dies and The Unnamable. The conventional understanding of waiting is as an intentional relationship between a waiting subject and an awaited object. This kind of waiting is end-directed, and, in order for it to be worthwhile, the awaited must, at some point, arrive. In the trilogy, however, the awaited never does arrive, and it is my contention that the novels are concerned with an unconventional kind of waiting, which, being without object or end, takes the form of a non-intentional relationship between waiter and awaited. Significantly, through the non-intentional wait, the subject awaits the unawaited. She or he thereby encounters the radically other, or that which cannot be rendered familiar or assimilated in any way – an unthinkable, unspeakable, ungraspable excess that overflows the limits of thought and language. The texts foreground the vexed question of response to such alterity: how can one approach the ungraspable as ungraspable, when it is in the nature of any approach to attempt to grasp? I argue that the texts explore a paradoxical form of "incurious seeking" as an avenue to accommodate the absolutely other.
- Full Text:
- Authors: Marais, Jessica
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3917 , vital:20557
- Description: In this thesis, I examine the interrelated roles of waiting and alterity in Samuel Beckett's trilogy of novels: Molloy, Malone Dies and The Unnamable. The conventional understanding of waiting is as an intentional relationship between a waiting subject and an awaited object. This kind of waiting is end-directed, and, in order for it to be worthwhile, the awaited must, at some point, arrive. In the trilogy, however, the awaited never does arrive, and it is my contention that the novels are concerned with an unconventional kind of waiting, which, being without object or end, takes the form of a non-intentional relationship between waiter and awaited. Significantly, through the non-intentional wait, the subject awaits the unawaited. She or he thereby encounters the radically other, or that which cannot be rendered familiar or assimilated in any way – an unthinkable, unspeakable, ungraspable excess that overflows the limits of thought and language. The texts foreground the vexed question of response to such alterity: how can one approach the ungraspable as ungraspable, when it is in the nature of any approach to attempt to grasp? I argue that the texts explore a paradoxical form of "incurious seeking" as an avenue to accommodate the absolutely other.
- Full Text:
2OS
- Authors: Machanick, Philip
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439214 , vital:73556 , https://homes.cs.ru.ac.za/philip/Courses/CS2-OS/Cs2ToOS.pdf
- Description: In this book I approach the problem of understanding an OS from the point of view of a C programmer who needs to understand enough of how an OS works to program efficiently and avoid traps and pitfalls arising from not understanding what is happening underneath you. If you have a deep understanding of the memory system, you will not program in a style that loses significant performance by breaking the assumptions of the OS designer. If you have an understanding of how IO works, you can make good use of OS services. As you work through this book you will see other examples.
- Full Text:
- Authors: Machanick, Philip
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439214 , vital:73556 , https://homes.cs.ru.ac.za/philip/Courses/CS2-OS/Cs2ToOS.pdf
- Description: In this book I approach the problem of understanding an OS from the point of view of a C programmer who needs to understand enough of how an OS works to program efficiently and avoid traps and pitfalls arising from not understanding what is happening underneath you. If you have a deep understanding of the memory system, you will not program in a style that loses significant performance by breaking the assumptions of the OS designer. If you have an understanding of how IO works, you can make good use of OS services. As you work through this book you will see other examples.
- Full Text:
A case for contemporary third literature: the black experience in the postmillennial fiction of three Kwela authors
- Authors: Mthembu, Lumumba
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3322 , vital:20480
- Description: This study seeks to uncover the manner in which the young black experience is constructed in three novels by Sifiso Mzobe, Kgebetli Moele and K. Sello Duiker. Young Blood, Untitled and Thirteen Cents all feature teenage narrators navigating the social milieu of South Africa in the twenty-first century. My analysis is informed by Frantz Fanon’s postcolonial theory because South Africa’s socio-economic landscape conforms to the divisions laid out in The Wretched of the Earth. I contend that post-apartheid South Africa is developing in a manner that is symptomatic of the Fanonian post-independence African state. My close reading of the novels teases out the conditions under which young black subjects must survive and express themselves. I look into the roles of the community, the government, the family, and the school in shaping this experience. Naturally, my discussion segues into questions of sexuality and gender as they intersect with race. I demonstrate how these texts fail and succeed as works of Third Literature, a genre derived from Third Cinema, which I have adapted due to its Fanonian ideological underpinning. Third Literature is a fundamentally revolutionary and activistic genre which seeks to pave the way for social change. In this regard, I concern myself with the recommendations these three authors may have for the readers of their texts. In conclusion, these texts demonstrate that racialized identities are social constructs with measurable experiential effects. However, there are ways of actively resisting or even
- Full Text:
- Authors: Mthembu, Lumumba
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3322 , vital:20480
- Description: This study seeks to uncover the manner in which the young black experience is constructed in three novels by Sifiso Mzobe, Kgebetli Moele and K. Sello Duiker. Young Blood, Untitled and Thirteen Cents all feature teenage narrators navigating the social milieu of South Africa in the twenty-first century. My analysis is informed by Frantz Fanon’s postcolonial theory because South Africa’s socio-economic landscape conforms to the divisions laid out in The Wretched of the Earth. I contend that post-apartheid South Africa is developing in a manner that is symptomatic of the Fanonian post-independence African state. My close reading of the novels teases out the conditions under which young black subjects must survive and express themselves. I look into the roles of the community, the government, the family, and the school in shaping this experience. Naturally, my discussion segues into questions of sexuality and gender as they intersect with race. I demonstrate how these texts fail and succeed as works of Third Literature, a genre derived from Third Cinema, which I have adapted due to its Fanonian ideological underpinning. Third Literature is a fundamentally revolutionary and activistic genre which seeks to pave the way for social change. In this regard, I concern myself with the recommendations these three authors may have for the readers of their texts. In conclusion, these texts demonstrate that racialized identities are social constructs with measurable experiential effects. However, there are ways of actively resisting or even
- Full Text:
A chiral hemiporphyrazine derivative
- Wu, Yanping, Gai, Lizhi, Xiao, Xuqiong, Lu, Hua, Li, Zhifang, Mack, John, Harris, Jessica, Nyokong, Tebello, Shen, Zhen
- Authors: Wu, Yanping , Gai, Lizhi , Xiao, Xuqiong , Lu, Hua , Li, Zhifang , Mack, John , Harris, Jessica , Nyokong, Tebello , Shen, Zhen
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240404 , vital:50831 , xlink:href="https://doi.org/10.1002/asia.201600754"
- Description: The synthesis of an optically active hemiporphyrazine with chiral binaphthyl substituents (1) is reported, providing the first example of the incorporation of an intrinsically chiral moiety into the macrocyclic core of a hemiporphyrazine analogue. A negative circular dichroism (CD) signal is observed in the 325–450 nm region of the CD spectrum of (S,S)-1, while mainly positive bands are observed in the 220–325 nm region. Mirror symmetry is observed across the entire wavelength range of the CD spectra of (R,R)-1 and (S,S)-1. An irreversible one-electron oxidation wave with an onset potential at 1.07 V is observed by cyclic voltammetry, along with a reversible one-electron reduction wave at −0.85 V. Density functional calculations reproduce the experimentally observed data and trends, and provide further insight into the nature of the electronic transitions.
- Full Text:
- Authors: Wu, Yanping , Gai, Lizhi , Xiao, Xuqiong , Lu, Hua , Li, Zhifang , Mack, John , Harris, Jessica , Nyokong, Tebello , Shen, Zhen
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240404 , vital:50831 , xlink:href="https://doi.org/10.1002/asia.201600754"
- Description: The synthesis of an optically active hemiporphyrazine with chiral binaphthyl substituents (1) is reported, providing the first example of the incorporation of an intrinsically chiral moiety into the macrocyclic core of a hemiporphyrazine analogue. A negative circular dichroism (CD) signal is observed in the 325–450 nm region of the CD spectrum of (S,S)-1, while mainly positive bands are observed in the 220–325 nm region. Mirror symmetry is observed across the entire wavelength range of the CD spectra of (R,R)-1 and (S,S)-1. An irreversible one-electron oxidation wave with an onset potential at 1.07 V is observed by cyclic voltammetry, along with a reversible one-electron reduction wave at −0.85 V. Density functional calculations reproduce the experimentally observed data and trends, and provide further insight into the nature of the electronic transitions.
- Full Text:
A combinatorial analysis of barred preferential arrangements
- Authors: Nkonkobe, Sithembele
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/36228 , vital:24530
- Description: For a non-negative integer n an ordered partition of a set Xn with n distinct elements is called a preferential arrangement (PA). A barred preferential arrangement (BPA) is a preferential arrangement with bars in between the blocks of the partition. An integer sequence an associated with the counting PA's of Xn has been intensely studied over a century and a half in many different contexts. In this thesis we develop a unified combinatorial framework to study the enumeration of BPAs and a special subclass of BPAs. The results of the study lead to a positive settlement of an open problem and a conjecture by Nelsen. We derive few important identities pertaining to the number of BPAs and restricted BPAs of an n element set using generating- functionology. Later we show that the number of restricted BPAs of Xn are intricately related to well-known numbers such as Eulerian numbers, Bell numbers, Poly-Bernoulli numbers and the number of equivalence classes of fuzzy subsets of Xn under some equivalent relation.
- Full Text:
- Authors: Nkonkobe, Sithembele
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/36228 , vital:24530
- Description: For a non-negative integer n an ordered partition of a set Xn with n distinct elements is called a preferential arrangement (PA). A barred preferential arrangement (BPA) is a preferential arrangement with bars in between the blocks of the partition. An integer sequence an associated with the counting PA's of Xn has been intensely studied over a century and a half in many different contexts. In this thesis we develop a unified combinatorial framework to study the enumeration of BPAs and a special subclass of BPAs. The results of the study lead to a positive settlement of an open problem and a conjecture by Nelsen. We derive few important identities pertaining to the number of BPAs and restricted BPAs of an n element set using generating- functionology. Later we show that the number of restricted BPAs of Xn are intricately related to well-known numbers such as Eulerian numbers, Bell numbers, Poly-Bernoulli numbers and the number of equivalence classes of fuzzy subsets of Xn under some equivalent relation.
- Full Text:
A comparative physicochemical study of unsymmetrical indium phthalocyanines in the presence of magnetic nanoparticles or quantum dots
- Osifeko, Olawale L, Nyokong, Tebello
- Authors: Osifeko, Olawale L , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188743 , vital:44781 , xlink:href="https://doi.org/10.1080/00958972.2016.1152628"
- Description: Asymmetric indium phthalocyanine (3, containing an NH2 group) was conjugated (via an amide bond) to magnetic nanoparticle (MNP) functionalized with carboxylic acid or glutathione-capped CdTe/ZnSe/ZnO quantum dots to form 3-MNPs or 3-QDs. Techniques such as time-resolved fluorescence measurements, transmission electron microscopy, XPS, elemental analysis, FTIR, NMR (1H, 13C, and cozy), electronic spectroscopy, as well as mass spectroscopy were employed to characterize 3 and its nanoconjugates. The phthalocyanine conjugated to quantum dot (3-QDs) possesses the lowest Фpd higher Ф∆ and ФT as well as longer triplet lifetimes compares to 3-MNPs and free phthalocyanine.
- Full Text:
- Authors: Osifeko, Olawale L , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188743 , vital:44781 , xlink:href="https://doi.org/10.1080/00958972.2016.1152628"
- Description: Asymmetric indium phthalocyanine (3, containing an NH2 group) was conjugated (via an amide bond) to magnetic nanoparticle (MNP) functionalized with carboxylic acid or glutathione-capped CdTe/ZnSe/ZnO quantum dots to form 3-MNPs or 3-QDs. Techniques such as time-resolved fluorescence measurements, transmission electron microscopy, XPS, elemental analysis, FTIR, NMR (1H, 13C, and cozy), electronic spectroscopy, as well as mass spectroscopy were employed to characterize 3 and its nanoconjugates. The phthalocyanine conjugated to quantum dot (3-QDs) possesses the lowest Фpd higher Ф∆ and ФT as well as longer triplet lifetimes compares to 3-MNPs and free phthalocyanine.
- Full Text:
A comparative study of syllables and morphemes as literacy processing units in word recognition: IsiXhosa and SeTswana
- Authors: Probert, Tracy Nicole
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3266 , vital:20415
- Description: Word recognition is a core foundation of reading (Invenizzi and Hayes 2010) and involves interactions of language skills, metalinguistic skills and orthography. The extent of the interaction with one another in reading has yet to be fully explored, especially in the Southern-Bantu languages. This comparative study of isiXhosa and Setswana explores this three-way interaction between language skills (effect of Language of Learning and Teaching (LoLT)), metalinguistic skills (Phonological and Morphological Awareness) and orthography (conjunctivism vs. disjunctivism). This thesis is novel in three respects, (a) a set of linguistic-informed reading measures were developed in isiXhosa and Setswana for the first-time, (b) to my knowledge, the comparisons made and study of Morphological Awareness in the Southern-Bantu languages have never been done, and (c) the use of d-prime as a way of testing for grain size in reading is an innovative approach. Grade 3 and Grade 4 learners were tested on four independent linguistic tasks: an open-ended decomposition task, a Phonological Awareness task, a Morphological Awareness task and an independent reading measure. These tasks were administered to determine the grain size unit (Ziegler and Goswami 2005, Ziegler et al. 2001) which learners use in word recognition, with the grain sizes of syllables and morphemes being studied. Results showed that syllables were the dominant grain size in both isiXhosa and Setswana, with morphemes as secondary grains in isiXhosa. Grain size differed slightly between the two orthographies. These results are reflected in the scores on the metalinguistic tasks. LoLT was not shown to have a significant impact on word recognition in first-language reading. The Psycholinguistic Grain Size Theory (PGST) was found to be the most applicable model of word recognition to the Southern- Bantu languages, as opposed to the Dual-Route Cascade Model and Orthographic Depth Hypothesis. This thesis concludes with suggested adaptations to this theory in order to allow for morpheme grain size to be included. This study has implications for teaching practice and curriculum design, and contributes to a broader understanding of literacy in the foundation phase in the Southern-Bantu languages.
- Full Text:
- Authors: Probert, Tracy Nicole
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3266 , vital:20415
- Description: Word recognition is a core foundation of reading (Invenizzi and Hayes 2010) and involves interactions of language skills, metalinguistic skills and orthography. The extent of the interaction with one another in reading has yet to be fully explored, especially in the Southern-Bantu languages. This comparative study of isiXhosa and Setswana explores this three-way interaction between language skills (effect of Language of Learning and Teaching (LoLT)), metalinguistic skills (Phonological and Morphological Awareness) and orthography (conjunctivism vs. disjunctivism). This thesis is novel in three respects, (a) a set of linguistic-informed reading measures were developed in isiXhosa and Setswana for the first-time, (b) to my knowledge, the comparisons made and study of Morphological Awareness in the Southern-Bantu languages have never been done, and (c) the use of d-prime as a way of testing for grain size in reading is an innovative approach. Grade 3 and Grade 4 learners were tested on four independent linguistic tasks: an open-ended decomposition task, a Phonological Awareness task, a Morphological Awareness task and an independent reading measure. These tasks were administered to determine the grain size unit (Ziegler and Goswami 2005, Ziegler et al. 2001) which learners use in word recognition, with the grain sizes of syllables and morphemes being studied. Results showed that syllables were the dominant grain size in both isiXhosa and Setswana, with morphemes as secondary grains in isiXhosa. Grain size differed slightly between the two orthographies. These results are reflected in the scores on the metalinguistic tasks. LoLT was not shown to have a significant impact on word recognition in first-language reading. The Psycholinguistic Grain Size Theory (PGST) was found to be the most applicable model of word recognition to the Southern- Bantu languages, as opposed to the Dual-Route Cascade Model and Orthographic Depth Hypothesis. This thesis concludes with suggested adaptations to this theory in order to allow for morpheme grain size to be included. This study has implications for teaching practice and curriculum design, and contributes to a broader understanding of literacy in the foundation phase in the Southern-Bantu languages.
- Full Text:
A comparison of muscle fatigue responses between static and quasi-static exertions
- Authors: Nel, Conrad
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3475 , vital:20502
- Description: Background: This study examined localized muscle fatigue responses from sub-maximal quasi-static work protocols and additionally how it compares to purely static work. The goal was to produce research that enhances the understanding of the demands on muscles during manual work to aid in preventing injuries stemming from localized muscle fatigue. Injury rates remain a problem in manual labour sectors, particularly for the lower back and shoulder regions for the manufacturing, service and construction sectors, and for knee and elbow flexors in the sports sector. Few studies have looked at quasi-static work and what the resulting fatigue characteristics are, especially when compared to purely static or purely dynamic work. This comparison is particularly important due to the fact that risk assessment tools that are currently utilized to assess risk in the working environment are based on fatigue studies that focus on purely static or purely dynamic work. This requires attention as many working situations are neither static nor dynamic, but rather quasi-static in nature, with aspects of both dynamic and static muscle components. The scope of this study only encompasses the comparison between purely static and quasi-static work. Objectives: This study had two objectives, firstly, to determine what the fatigue characteristics of quasi-static work are and how it compares to fully static work. Secondly, to determine whether an underlying static component within an otherwise dynamic muscle force affects localized muscle fatigue compared to quasi-static work that has equal amounts of effort but with no underlying static component. Methods: Four experimental conditions were tested, each on four muscles, namely the medial deltoid, bicep brachii, bicep femoris and erector spinae muscles. To test the two objectives of this study, 16 volunteers performed a five minute fatigue protocol, that either entailed a fully static condition which involved: 1) producing a steady force at 25 percent of maximum voluntary force, 2) a quasi-static condition with fully dynamic muscle force that alternates the required force level between zero and 50 percent of maximum force, 3) a quasi-static condition with an underlying static component of five percent of maximum force, or 4) a quasi-static condition with a large underlying static component of 15 percent of maximum force. All the experimental conditions in this study had the same average workload of 25 percent of maximum voluntary force over time and thus total workload. The dependant variables of interest were ratings of perceived exertion, changes in muscle fibre recruitment (% of maximum EMG activity), maximum force and center frequency from a spectral analysis of the surface electromyography. These were measured throughout the protocols at one minute intervals to determine how muscle fatigue progressed, and how the fatigue responses differed between conditions. Results: The data from comparing fully static and quasi-static work showed that of the variables measured, the rating of perceived exertion (RPE) and maximum force data indicated that for bicep brachii and bicep femoris muscles, fully static work is more fatiguing than work that alternates between zero and 50 percent of maximum force. The results for the medial deltoid and erector spinae muscles were inconclusive. The findings regarding the comparison between quasi-static conditions with and without an underlying static component revealed that an underlying static component results in greater fatigue when compared to a quasi-static condition with no static component. The results may also suggest that a larger static component coupled with a smaller peak force results in less fatigue than a condition with a small underlying static component coupled with a higher peak force in some scenarios, provided total work is kept constant. All conditions had to have the same workload in order to be validly compared and thus the condition with a larger underlying static component had a lower peak force compared to the condition with no underlying static component or the condition with a small underlying static component. Conclusions: This study presented evidence that quasi-static work does not induce fatigue when measured by RPE and drop in maximum force in the same way as static work. Additionally, the results indicate that a larger underlying static component does not necessarily fatigue a muscle faster if the overall workload is kept constant. However, the results do suggest that any underlying static component will increase the demand on a muscle when compared to a muscle exertion with no static component. When considering the available literature on how muscles fatigue during low level static contractions, the current understanding is that the larger the force during a static contraction, the faster the onset of fatigue and decrements in performance occur. The results of this study suggest that this same relationship cannot be applied to quasi-static work where an underlying static component is part of an otherwise dynamic muscle force. Thus total workload or peak force may play a larger role than the static muscle exertion in some scenarios.
- Full Text:
- Authors: Nel, Conrad
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3475 , vital:20502
- Description: Background: This study examined localized muscle fatigue responses from sub-maximal quasi-static work protocols and additionally how it compares to purely static work. The goal was to produce research that enhances the understanding of the demands on muscles during manual work to aid in preventing injuries stemming from localized muscle fatigue. Injury rates remain a problem in manual labour sectors, particularly for the lower back and shoulder regions for the manufacturing, service and construction sectors, and for knee and elbow flexors in the sports sector. Few studies have looked at quasi-static work and what the resulting fatigue characteristics are, especially when compared to purely static or purely dynamic work. This comparison is particularly important due to the fact that risk assessment tools that are currently utilized to assess risk in the working environment are based on fatigue studies that focus on purely static or purely dynamic work. This requires attention as many working situations are neither static nor dynamic, but rather quasi-static in nature, with aspects of both dynamic and static muscle components. The scope of this study only encompasses the comparison between purely static and quasi-static work. Objectives: This study had two objectives, firstly, to determine what the fatigue characteristics of quasi-static work are and how it compares to fully static work. Secondly, to determine whether an underlying static component within an otherwise dynamic muscle force affects localized muscle fatigue compared to quasi-static work that has equal amounts of effort but with no underlying static component. Methods: Four experimental conditions were tested, each on four muscles, namely the medial deltoid, bicep brachii, bicep femoris and erector spinae muscles. To test the two objectives of this study, 16 volunteers performed a five minute fatigue protocol, that either entailed a fully static condition which involved: 1) producing a steady force at 25 percent of maximum voluntary force, 2) a quasi-static condition with fully dynamic muscle force that alternates the required force level between zero and 50 percent of maximum force, 3) a quasi-static condition with an underlying static component of five percent of maximum force, or 4) a quasi-static condition with a large underlying static component of 15 percent of maximum force. All the experimental conditions in this study had the same average workload of 25 percent of maximum voluntary force over time and thus total workload. The dependant variables of interest were ratings of perceived exertion, changes in muscle fibre recruitment (% of maximum EMG activity), maximum force and center frequency from a spectral analysis of the surface electromyography. These were measured throughout the protocols at one minute intervals to determine how muscle fatigue progressed, and how the fatigue responses differed between conditions. Results: The data from comparing fully static and quasi-static work showed that of the variables measured, the rating of perceived exertion (RPE) and maximum force data indicated that for bicep brachii and bicep femoris muscles, fully static work is more fatiguing than work that alternates between zero and 50 percent of maximum force. The results for the medial deltoid and erector spinae muscles were inconclusive. The findings regarding the comparison between quasi-static conditions with and without an underlying static component revealed that an underlying static component results in greater fatigue when compared to a quasi-static condition with no static component. The results may also suggest that a larger static component coupled with a smaller peak force results in less fatigue than a condition with a small underlying static component coupled with a higher peak force in some scenarios, provided total work is kept constant. All conditions had to have the same workload in order to be validly compared and thus the condition with a larger underlying static component had a lower peak force compared to the condition with no underlying static component or the condition with a small underlying static component. Conclusions: This study presented evidence that quasi-static work does not induce fatigue when measured by RPE and drop in maximum force in the same way as static work. Additionally, the results indicate that a larger underlying static component does not necessarily fatigue a muscle faster if the overall workload is kept constant. However, the results do suggest that any underlying static component will increase the demand on a muscle when compared to a muscle exertion with no static component. When considering the available literature on how muscles fatigue during low level static contractions, the current understanding is that the larger the force during a static contraction, the faster the onset of fatigue and decrements in performance occur. The results of this study suggest that this same relationship cannot be applied to quasi-static work where an underlying static component is part of an otherwise dynamic muscle force. Thus total workload or peak force may play a larger role than the static muscle exertion in some scenarios.
- Full Text:
A corpus-based approach to writing in German as a foreign language in the South African tertiary context
- Authors: Ortner, Gwyndolen Jeanie
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3660 , http://hdl.handle.net/10962/d1021256
- Description: German Studies students at Rhodes University have normally never studied the German language before enrolling for the first-year course and face the challenge of a fairly rapid linguistic advancement in order to engage meaningfully with the literatures and cultures of German-speaking countries. This thesis investigates the process of teaching and learning to write in a more academic way in German as a foreign language at Rhodes University, using corpus linguistic tools for both analysis and instruction. The past 20 years have shown a shift from traditional teaching methods resting on notions of an underlying prescriptive grammar, to teaching based on insights from real-life language data (Gabrielatos, 2005; Krummes & Ensslin, 2012; Sinclair, 1997) and applications of corpora to teaching and learning have shown to be highly successful in many European contexts (Aijmer, 2010; Johns, 1991; Granger, et al., 2002; Varley, 2009). In the South African context however, this is a relatively new concept with few publications on the application of corpus linguistics to language teaching (Van Rooy, 2008), and one which does not seem to have reached its full potential. A writing course was instituted whose aim was two-fold: 1. to teach learners “every-day academic” German words (TAG words) and phrases (collocations) based on German mother-tongue corpus evidence; 2. to have learners write short assignments in German at regular intervals (Homstad & Thorson, 1996; Estes, et al., 1998); both aims with the overarching objective to improve the students’ academic register in German. After the writing course, 80% of the participants perceived that their writing had improved and specifically attributed this to the corpus-based instruction received during the writing course, and regular writing in German. Quantitative data (from the learner corpus created) shows a marked improvement in the use of the collocations taught. Moreover, participants (weaker students in particular) also found that their writing in English had improved as a result of the various exercises they had to complete as part of our German writing course.
- Full Text:
- Authors: Ortner, Gwyndolen Jeanie
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3660 , http://hdl.handle.net/10962/d1021256
- Description: German Studies students at Rhodes University have normally never studied the German language before enrolling for the first-year course and face the challenge of a fairly rapid linguistic advancement in order to engage meaningfully with the literatures and cultures of German-speaking countries. This thesis investigates the process of teaching and learning to write in a more academic way in German as a foreign language at Rhodes University, using corpus linguistic tools for both analysis and instruction. The past 20 years have shown a shift from traditional teaching methods resting on notions of an underlying prescriptive grammar, to teaching based on insights from real-life language data (Gabrielatos, 2005; Krummes & Ensslin, 2012; Sinclair, 1997) and applications of corpora to teaching and learning have shown to be highly successful in many European contexts (Aijmer, 2010; Johns, 1991; Granger, et al., 2002; Varley, 2009). In the South African context however, this is a relatively new concept with few publications on the application of corpus linguistics to language teaching (Van Rooy, 2008), and one which does not seem to have reached its full potential. A writing course was instituted whose aim was two-fold: 1. to teach learners “every-day academic” German words (TAG words) and phrases (collocations) based on German mother-tongue corpus evidence; 2. to have learners write short assignments in German at regular intervals (Homstad & Thorson, 1996; Estes, et al., 1998); both aims with the overarching objective to improve the students’ academic register in German. After the writing course, 80% of the participants perceived that their writing had improved and specifically attributed this to the corpus-based instruction received during the writing course, and regular writing in German. Quantitative data (from the learner corpus created) shows a marked improvement in the use of the collocations taught. Moreover, participants (weaker students in particular) also found that their writing in English had improved as a result of the various exercises they had to complete as part of our German writing course.
- Full Text:
A critical analysis of agricultural innovation platforms among small-scale farmers in Hwedza communal area, Zimbabwe
- Authors: Mahiya, Innocent Tonderai
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/596 , vital:19973
- Description: Agricultural research has existed for many decades at national and global levels and research-based agricultural interventions, often driven by the state, have taken place across Africa over an extended period. But, overall, these interventions have not generated the high potential and kinds of outcomes expected of them in terms of enhancing agricultural productivity amongst small-scale farmers and improving the quality of their agrarian lives. In the context of neoliberal restructuring globally, new forms of agricultural interventions have arisen which highlight the significance of more participatory methodologies in which non-governmental organisations become central. One such methodology rests on the notion of an agricultural innovation platform which involves bringing on board a diverse range of actors (or stakeholders) which function together to generate agricultural knowledge and practices suitable to the needs of a particular small-scale farming community, with the small-scale farmers expected to be key actors in the platform. Such platforms are now being implemented in specific rural sites in Zimbabwe, including in communal areas in the district of Hwedza where farming activities have for many years now being in large survivalist in character. The objective of this thesis is to critically analyse the agricultural innovation platforms in Hwedza, but not in the sense of assessing the impact of the platforms on agricultural productivity. Rather, the thesis examines the multi-faceted social interactions and relationships embodied in the innovation platform process. In pursuing this, I rely heavily – but in a critical manner – on interface analysis as set out by Norman Long. The fieldwork for the Hwedza involved an interpretative-qualitative methodology based on methods such as in-depth interviews, focus group discussions, questionnaires and observations. The major finding of the thesis is that the agricultural innovation platforms, at least as implemented in Hwedza, do challenge top-down approaches to agricultural interventions by unlocking the possibility of multiple pathways of inclusion and particularly for small-scale farmers but that, simultaneously, they also involve processes marked by divergences, exclusions, tensions and conflicts which may undermine the legitimacy and effectiveness of the platforms.
- Full Text:
- Authors: Mahiya, Innocent Tonderai
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/596 , vital:19973
- Description: Agricultural research has existed for many decades at national and global levels and research-based agricultural interventions, often driven by the state, have taken place across Africa over an extended period. But, overall, these interventions have not generated the high potential and kinds of outcomes expected of them in terms of enhancing agricultural productivity amongst small-scale farmers and improving the quality of their agrarian lives. In the context of neoliberal restructuring globally, new forms of agricultural interventions have arisen which highlight the significance of more participatory methodologies in which non-governmental organisations become central. One such methodology rests on the notion of an agricultural innovation platform which involves bringing on board a diverse range of actors (or stakeholders) which function together to generate agricultural knowledge and practices suitable to the needs of a particular small-scale farming community, with the small-scale farmers expected to be key actors in the platform. Such platforms are now being implemented in specific rural sites in Zimbabwe, including in communal areas in the district of Hwedza where farming activities have for many years now being in large survivalist in character. The objective of this thesis is to critically analyse the agricultural innovation platforms in Hwedza, but not in the sense of assessing the impact of the platforms on agricultural productivity. Rather, the thesis examines the multi-faceted social interactions and relationships embodied in the innovation platform process. In pursuing this, I rely heavily – but in a critical manner – on interface analysis as set out by Norman Long. The fieldwork for the Hwedza involved an interpretative-qualitative methodology based on methods such as in-depth interviews, focus group discussions, questionnaires and observations. The major finding of the thesis is that the agricultural innovation platforms, at least as implemented in Hwedza, do challenge top-down approaches to agricultural interventions by unlocking the possibility of multiple pathways of inclusion and particularly for small-scale farmers but that, simultaneously, they also involve processes marked by divergences, exclusions, tensions and conflicts which may undermine the legitimacy and effectiveness of the platforms.
- Full Text: