https://commons.ru.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://commons.ru.ac.za/vital/access/manager/Repository/vital:26623 Wed 12 May 2021 20:17:12 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:26607 Wed 12 May 2021 17:33:21 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:26751 Wed 12 May 2021 16:19:00 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:26580 99 % in selectively extracting the metalloporphyrins. The impact of the template on the affinity of recognition for NTPP was evaluated. The results showed that the NTPP adsorption capacity increased as the molar ratio of NTPP to styrene was increased from 1:1 to 3:1. The optimal ratio of template to functional monomer which yielded the best specific affinity and highest recovery (99.9 %) was 3:1. The effects of trifluoroacetic acid (TFA), dichloromethane (DCM), dimethyl sulphoxide (DMSO), pentane (PEN) on electro-spinnability of the polymer solutions and the morphological appearance of the nanofibers were investigated. The imprinted nanofibers exhibited the same selectivity specialism for both NTPP and VTPP. A remarkable stability in relation to reusability was observed when imprinted nanofibers were used, as they could be reused nine times without incurring any significant loss in removal efficiency. The results were validated by analysing a certified reference material. The imprinted sorbents were therefore found to be selective sorbents that are well suited for handling trace metals in organic media.]]> Thu 13 May 2021 09:54:20 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28540 Thu 13 May 2021 07:35:41 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:29380 20% habitat loss due to invasion). Upstream invasion by centrarchids isolated and fragmented P. afer populations into headwater refugia, while top down invasion by salmonids excluded B. trevelyani from invaded, more pristine stream reaches, by forcing the species into degraded unsuitable lower stream reaches. Predation also disrupted population processes such as adult dispersal for P. afer, and centrarchid-invaded zones acted as demographic sinks, where adults dispersing through invaded reaches were rapidly depleted. While the Mandela lineage of P. afer exhibited little within or between drainage genetic structuring, B. trevelyani was >4% divergent between drainages, and up to 2% divergent between streams within the Keiskamma River system (Chapter 7). The distribution of genetic diversity for B. trevelyani also indicated that the loss of diversity was imminent without immediate conservation interventions. This thesis has provided conclusive evidence that native fishes are vulnerable to invasion and that non-native predatory fishes have significant impacts on native fishes in Eastern Cape headwater streams. If management and conservation measures are implemented, the unwanted introduction and spread of non-native fishes may be restricted, allowing native fishes opportunities for recovery.]]> Thu 13 May 2021 07:28:56 SAST ]]>