https://vital.seals.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://vital.seals.ac.za/vital/access/manager/Repository/vital:9757 Wed 12 May 2021 23:30:42 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2219 Wed 12 May 2021 23:24:45 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10577 Wed 12 May 2021 23:21:23 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1541 Wed 12 May 2021 23:04:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9755 Wed 12 May 2021 22:50:30 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5785 Wed 12 May 2021 22:17:34 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9068 Wed 12 May 2021 21:02:59 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10646 10 percent), are fine textured (>50 percent of the material passing the 0.075mm sieve) and highly plastic. These soil attributes imply low permeability, excessive water retention and high susceptibility to expansion and sliding. The vertic nature of soils at Nametsi was confirmed by the extremely high plasticity indices (averaging 33percent), while, high liquid limits at Buwabwala (53 percent) and Kitati (59 percent) qualified the soils as vertisols which are associated with landslides. The results point to the fact that soils at landslide sites are inherently ‘problem soils’ where slope failure can occur even without human intervention. Therefore, the hypothesis that soils at three landslide sites are inherently ‘problem soils’ where slope failure can occur even without human intervention is accepted. Notwithstanding the fact that the study was focussed on mid-altitude slopes of Mt Elgon, the results are in tandem with investigations carried out earlier on the lower densely populated slopes, thus confirming the widespread nature of problem soils on Mt Elgon. There is an urgent need to control human population growth and restore forest cover on the heavily deforested steep slopes particularly within the National Park, and restrain communities from encroaching on the pristine slopes of Mt Elgon. This will be achieved if the politicians, Park Authorities and local communities jointly participate in the design and implementation of CFMs. Future research could focus on climate change implications of deforestation of Mt Elgon environments and quantification of carbon loss related to deforestation and soil degradation in the mountain environments.]]> Wed 12 May 2021 21:01:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10136 Wed 12 May 2021 20:37:34 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9807 Wed 12 May 2021 20:31:17 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4927 75 million carats recovered at >95% gem quality) comprises onshore and offshore marine deposits that are developed within ∼100km of the Orange River outfall. For much of the Cainozoic, this long-lived fluvial system has been the main conduit transporting diamonds from kimberlitic and secondary sources in the cratonic hinterland of southern Africa to the Atlantic shelf that has been neutrally buoyant over this period. Highly energetic marine processes, driven in part, by southerly winds with an attendant northward-directed longshore drift, have generated terminal placers that are preserved both onshore and offshore. This study, through detailed field sedimentological and diamond analyses, investigates the development and mineralisation of gravel barrier deposits within the ancestral Orange River mouth area during a major ∼30 m regional transgression ('30 m Package') in the Late Pliocene. At that time, diamond supply from this fluvial conduit was minimal, yet the corresponding onshore marine deposits to the north of the Orange River mouth were significantly diamond enriched, enabling large-scale alluvial diamond mining to take place for over 75 years. Of the entire coastline of south-western Africa, the most complete accumulation of the '30 m Package' is preserved within the palaeo-Orange River mouth as barrier spit and barrier beach deposits. Arranged vertically and laterally in a 16m thick succession, these are deposits of: (1) intertidal beach, (2) lagoon and washover, (3) tidal inlet and spit recurve and (4) storm-dominated subtidal settings. These were parts of larger barrier features, the bulk of which are preserved as highstand deposits that are diamond-bearing with varying, but generally low grades (<13 stones (diamonds) per hundred tons, spht). Intertidal beach and spit recurve deposits have higher economic grades (12-13 spht) due to the energetic sieving and mobile trapping mechanisms associated with their emplacement. In contrast, the less reworked and more sandy subtidal, tidal inlet and washover deposits have un-economic grades (<2 spht). Despite these low grades, the barrier deposits have the largest average stone (diamond) size (1-2 carats/stone, cts/stn) of the entire Namibian mega-placer, given their proximity to the ancestral Orange River outfall. This study demonstrates that barrier shoreline evolution at the fluvial/marine interface was controlled by: (1) a strong and coarse fluvial sediment supply that sustained shoreline growth on a highly energetic coast, (2) accommodation space facilitating sediment preservation and (3) short-duration, high-frequency sea-level cycles superimposed on the∼30 m regional transgression, promoting hierarchal stacking of progradational deposits. During these sea-level fluctuations, diamonds were 'farmed' from older, shelf sequences in the offshore and driven landward to accumulate in '30 m Package' highstand barrier deposits. In spite of the large supply of diamonds, their retention in these deposits was poor due to an incompetent footwall of ancestral Orange River mouth sediment and the inherent cobble-boulder size of the barrier gravels. Thus the principal process controlling diamond entrapment in these barrier deposits was kinetic sieving in a coarse-grained framework. Consequently, at the marine/fluvial interface and down-drift for ∼5 km, larger diamonds (1-2 cts/stn) were retained in low-grade (<2 spht), coarse-gravel barrier shorelines. Smaller diamonds (mostly < I cts/stn) were rejected into the northward-driven littoral sediments and further size-sorted along ∼95 km of Namibian coast to accumulate in finer, high-grade beach placers (> 100 spht) where bedrock footwall promoted such high concentrations. The gravel-dominated palaeo-Orange River mouth is considered to be the ' heart' of the Namibian mega-placer, controlling sediment and diamond supply to the littoral zone further north. Although coarse gravel is retained at the river mouth, the incompetence of this highly energetic setting to trap diamonds renders it sub-economic. This ineffectiveness at the fluvial/marine interface is thus fundamental in enriching the coastal tract farther down-drift and developing highly economic coastal placers along the Atlantic coast of south-western Africa.]]> Wed 12 May 2021 20:08:03 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3859 Wed 12 May 2021 19:39:20 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4201 Wed 12 May 2021 19:25:43 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4419 Wed 12 May 2021 19:14:46 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9683 Wed 12 May 2021 19:02:47 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:8644 Wed 12 May 2021 18:38:39 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3013 Wed 12 May 2021 18:37:06 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:6039 Wed 12 May 2021 18:26:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4101 Wed 12 May 2021 18:21:27 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4355 Wed 12 May 2021 18:09:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3991 Wed 12 May 2021 17:52:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3318 Wed 12 May 2021 17:41:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2094 Wed 12 May 2021 17:14:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4338 Wed 12 May 2021 16:51:46 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5451 Wed 12 May 2021 16:24:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9358 Wed 12 May 2021 16:08:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5825 Wed 12 May 2021 16:03:06 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:977 Wed 12 May 2021 16:02:46 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5762 Wed 12 May 2021 16:00:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4780 Wed 12 May 2021 15:48:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2377 Wed 12 May 2021 15:47:03 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10336 Wed 12 May 2021 15:44:08 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4310 Tue 24 Aug 2021 16:28:07 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3025 40 years), which were then differentiated according to gender, reproductive status, and relationship status. Treating the interviews as jointly produced narratives, I analysed them by means of a performativity/performance lens. This dual analytic lens focuses on how particular narrative performances are simultaneously shaped by the interview setting and the broader discursive context. The lens was fashioned by synthesising Butler’s theory of performativity with Taylor’s narrative-discursive method. This synthesis (1) allows for Butler’s notion of “performativity” to be supplemented with that of “performance”; (2) provides a concrete analytical strategy in the form of positioning analysis; and (3) draws attention to both the micro politics of the interview conversation and the operation of power on the macro level, including the possibility of making “gender trouble”. The findings of the study suggest that the participants experienced difficulty narrating about male involvement in parenthood decision-making, owing to the taken for granted nature of parenthood for heterosexual adults. This was evident in participants’ sidelining of issues of “deciding” and “planning” and their alternate construal of childbearing as a non-choice, which, significantly served to bolster hetero-patriarchal norms. A central rhetorical tool for accomplishing these purposes was found in the construction of the “sacralised” child. In discursively manoeuvring around the central problematic, the participants ultimately produced a “silence” in the data that repeats the one in the research literature.]]> Tue 15 Aug 2023 16:06:17 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3949 Thu 13 May 2021 13:31:40 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26827 Thu 13 May 2021 08:53:07 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9385 Thu 13 May 2021 08:11:25 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:6037 Thu 13 May 2021 07:39:03 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9477 Thu 13 May 2021 07:26:10 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4777 Thu 13 May 2021 06:53:03 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4073 Thu 13 May 2021 06:37:23 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10603 Thu 13 May 2021 06:19:11 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5760 Thu 13 May 2021 05:23:38 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4321 Thu 13 May 2021 05:22:21 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1855 Thu 13 May 2021 05:15:17 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3952 Thu 13 May 2021 04:58:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10506 (Kw + $) −W . This result shows that the warthog’s equilibrium population density is bounded above by population thresholds, i.e., W < (Kw+$). Besides showing the occurrence under parameter space of the so-called paradox of enrichment, early indicators of chaos can also be deduced. In addition, numerical results revealed stable oscillatory behaviour and stable spirals of the species as predator fertility rate, mortality rate and prey threshold were varied. The stabilising effect of prey refuge due to variations in predator fertility and proportion of prey in the refuge was studied. Formulation and analysis of a robust mathematical model for two predators having an overlapping dietary niche were also done. The Beddington-DeAngelis functional and numerical responses which are relevant in addressing the Principle of Competitive Exclusion as species interact were incorporated in the model. The stabilizing effect of additional food in relation to the relative diffusivity D, and wave number k, was investigated. Stability, dissipativity, permanence, persistence and periodicity of the model were studied using the routine and limit cycle perturbation methods. The periodic solutions (b 1 and b 3), which influence the dispersal rate (') of the interacting species, have been shown to be controlled by the wave number. For stability, and in order to overcome predator natural mortality, the nutritional value of predator additional food has been shown to be of high quality that can enhance predator fertility gain. The threshold relationships between various ecosystem parameters and the carrying capacity of the game park for the prey species were also deduced to ensure ecosystem persistence. Besides revealing irregular periodic travelling wave behaviour due to predator interference, numerical results also show oscillatory temporal dynamics resulting from additional food supplements combined with high predation rates.]]> Thu 13 May 2021 04:45:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4204 Thu 13 May 2021 04:43:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9499 Thu 13 May 2021 04:23:27 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10544 Thu 13 May 2021 04:18:24 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4365 Thu 13 May 2021 03:50:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9753 Thu 13 May 2021 03:43:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4369 Thu 13 May 2021 03:41:05 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2246 Thu 13 May 2021 03:08:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3035 Thu 13 May 2021 02:44:55 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9678 Thu 13 May 2021 02:41:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5311 Thu 13 May 2021 02:41:00 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3967 Thu 13 May 2021 02:10:17 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:27035 Thu 13 May 2021 02:03:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4372 Thu 13 May 2021 01:49:31 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3305 Thu 13 May 2021 01:47:46 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3299 Thu 13 May 2021 01:26:32 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5806 Thu 13 May 2021 00:46:22 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10597 Thu 13 May 2021 00:35:38 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10647 Thu 13 May 2021 00:17:10 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9645 Thu 13 May 2021 00:14:49 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10537 580 ˚C) growth temperatures reduce the Mg incorporation. High VI/II ratios also decrease the Mg incorporation, as evidenced by the red-shift of the donor bound exciton (D°X) line. This is ascribed to a stronger premature reaction between (MeCp)2Mg and the oxidant or a preferential heterogeneous interaction between the Mg and oxygen species on the growth front. For both oxidizing agents (O2 and TBOH), the growth at 420 ˚C and a VI-II ratio of 60 on c-Al2O3 gave optimal quality layers in terms of their optical and structural quality. A comparison of films grown using TBOH and O2 gas as oxidizing agent shows no major difference in terms of Mg incorporation. The effect of annealing, the inclusion of a buffer layer and the influence of growth rate on the properties MgxZn1-xO thin films are also reported.]]> Thu 13 May 2021 00:01:15 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4593 Thu 07 Jul 2022 20:21:17 SAST ]]>