https://vital.seals.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://vital.seals.ac.za/vital/access/manager/Repository/vital:28265 Wed 13 Mar 2024 14:17:24 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10495 Wed 12 May 2021 23:47:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10408 Wed 12 May 2021 23:36:03 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:29120 Wed 12 May 2021 23:31:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:27041 Wed 12 May 2021 23:25:12 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:20677 Thu 13 May 2021 13:21:29 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:29284 Thu 13 May 2021 13:20:37 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10430 Thu 13 May 2021 11:17:38 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26423 Thu 13 May 2021 08:53:16 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:10532 Thu 13 May 2021 08:50:32 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10329 Thu 13 May 2021 08:22:46 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:27888 Thu 13 May 2021 08:19:50 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26960 Thu 13 May 2021 07:38:12 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10339 Thu 13 May 2021 07:36:07 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10637 7 days) but could survive submergence of short duration (< 7 days) through continuous underwater photosynthesis, accumulation of osmolytes such as oxalic acid and carotenoid, and maintenance of relative water content and succulence within control levels. When considered together, results showed that the two upper intertidal species were sensitive to waterlogging and would not survive complete submergence, whereas the lower intertidal species could in addition to its natural range, thrive in conditions typical of the upper intertidal range, namely prolonged dry conditions and high sediment salinity. These results have important implications for the future management of salt marshes under predicted climate change conditions. In permanently open South African estuaries, a landward migration of salt marsh will be possible if coastal squeeze is limited and the rate of landward recruitment is on par with sea level rise. In this case salt marsh species would retain their current zonation while shifting inland. Increased sea storms and saltwater intrusion could lead to high salinity concentration in the sediment and significantly reduce growth of salt-sensitive plants. In estuaries that are temporarily open to the sea, reduced freshwater inflow will result in an increase in mouth closure, high water levels, prolonged submergence, and consequently die back of salt marsh vegetation. On the other hand increased abstraction and drought would result in low water levels and high sediment salinity which would decrease growth and survival of salt marsh. This research has provided new knowledge on the ecophysiology of salt marsh plants which can be used to predict the responses of plants to climate change.]]> Thu 13 May 2021 07:33:25 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:35989 Thu 13 May 2021 07:31:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:27835 Thu 13 May 2021 07:25:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26968 _D 2 suffciently large, a non-constant positive solution is generated, that is, stationary patterns emerge, depicting dispersal of species. Predators were observed to occupy habitats surrounding prey. However, super-predators were observed to alternate their habitats, from staying away from prey to invading prey habitat. In the investigation, strategies to determine ways in which the predator species could be saved from extinction and its population improved were devised, and these included isolation of the predator from the super-predator.]]> Thu 13 May 2021 07:24:20 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10598 Thu 13 May 2021 07:20:35 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10670 Thu 13 May 2021 07:19:36 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:21137 Thu 13 May 2021 07:18:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10559 Thu 13 May 2021 07:18:21 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10641 Thu 13 May 2021 07:16:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10507 Thu 13 May 2021 07:05:24 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10672 Thu 13 May 2021 07:02:31 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10338 Thu 13 May 2021 07:01:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26925 Thu 13 May 2021 06:52:01 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:20441 Thu 13 May 2021 06:50:39 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:38169 Thu 13 May 2021 06:45:15 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:21071 Thu 13 May 2021 06:31:44 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:10607 Thu 13 May 2021 06:16:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36231 Thu 13 May 2021 06:13:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:21141 Thu 13 May 2021 06:11:45 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10550 Thu 13 May 2021 05:57:43 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10321 sCD23>derCD23) for IgE, upon increasing length of the proximal CD23 “stalk” domain. These findings highlight the differences in both the structural basis and affinity of the three physiological fragments of human CD23 for the ligands CD21 and IgE and underscore the complexity of CD23-mediated regulatory networks. It was found that B-cells only make up ~5% of the PBMC population, and that these cells were able to be activated, via STAT-6 phosphorylation, to enter class switch recombination (CSR) by the addition of switch factors (IL-4 and anti-CD40). Titration experiments dictated that 25 ng/mL of CD23 was the most efficient concentration to up-regulate IgE synthesis in PBMCs; furthermore, soluble CD23 proteins were incubated with PBMCs in the presence and absence of CD21 SCR 1-2 to investigate the effect that these recombinant proteins have on IgE synthesis. Results showed that the influence of recombinant proteins (both CD23 and CD21) on IgE synthesis was slight. It was shown that while derCD23 had no significant effect, monomeric sCD23 down-regulated, and the mixture of monomeric and oligomeric exCD23 up-regulated IgE synthesis. On addition of CD21 SCR 1-2 to the cells switched and treated with soluble CD23, it was found that in both cases for sCD23 and exCD23, IgE synthesis was increased, while for derCD23, there was no noticeable difference in IgE synthesis. This confirmed previous data showing the lack of binding between derCD23 and CD21 SCR 1-2. The exact binding site for CD21 on the CD23 molecule is unknown, and incompletely represented in the NMR and crystal structures. It is thought that CD21 binds to the C-terminal tail section, not present in derCD23. It is therefore likely that only a negative-feedback mechanism operates with derCD23 to regulate IgE synthesis. Further investigation of the binding of CD23 fragments to SCR 5-8 of CD21 and the effect of this on IgE synthesis may lead to a potential therapeutic role for derCD23 in the treatment of allergic disease. Data accumulated in this study suggests that investigating the modulation of oligomeric state and thus the activity of soluble CD23 fragments may be important in the construction of new regulators of IgE synthesis.]]> Thu 13 May 2021 05:44:14 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26433 0.3. The possibility that Si could become a DX-centre in AlxGa1-xN was then investigated. However, Hall effect measurements showed that the Si activation energy increased in good agreement with the model of a shallow effective mass state donor, with no sudden increase in ED being observed up to x = 0.4. It was then suggested that the increase in the E1 and E2 activation energies, as well as the exciton localisation energies, could be due to the 9 7 valence band crossover, which occurs at roughly the same composition. However, due to the scarcity of reports on the valence band structure in AlxGa1-xN no conclusions could be made at this stage as to the effect of the 9 7 valence band crossover on the PL properties of AlxGa1-xN.]]> Thu 13 May 2021 05:42:11 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:31347 Thu 13 May 2021 05:31:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:21001 Thu 13 May 2021 05:30:49 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10613 Thu 13 May 2021 05:28:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10502 Thu 13 May 2021 05:15:37 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:29504 Thu 13 May 2021 05:06:49 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10444 Thu 13 May 2021 05:01:05 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:27153 Thu 13 May 2021 04:53:06 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:21109 Thu 13 May 2021 04:42:08 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10303 Thu 13 May 2021 04:27:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10606 Thu 13 May 2021 04:26:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36280 Thu 13 May 2021 04:21:00 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:10548 Thu 13 May 2021 04:10:03 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:11085 Thu 13 May 2021 04:09:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10404 Thu 13 May 2021 04:05:40 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10538 Thu 13 May 2021 04:03:36 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10668 Thu 13 May 2021 03:57:49 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10323 Thu 13 May 2021 03:53:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10555 Thu 13 May 2021 03:51:44 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:33447 Thu 13 May 2021 03:47:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10322 Thu 13 May 2021 03:37:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:11093 Thu 13 May 2021 03:35:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10372 Thu 13 May 2021 03:30:44 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:21162 Thu 13 May 2021 03:15:07 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:35287 Thu 13 May 2021 03:09:01 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10350 Thu 13 May 2021 02:45:06 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:20817 Thu 13 May 2021 02:30:07 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:27301 Thu 13 May 2021 02:23:07 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30934 Thu 13 May 2021 02:22:08 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10619 Thu 13 May 2021 02:22:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10530 Thu 13 May 2021 02:15:33 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:34124 Thu 13 May 2021 02:13:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:27106 Thu 13 May 2021 02:00:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10469 Thu 13 May 2021 01:58:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10687 Thu 13 May 2021 01:55:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:29817 m-toluidine > o-toluidine) and the cresols (p-cresol > m-cresol > o-cresol). Each guest mixture was selected based on data from experiments using either the industrial significance of its separation or because the mixture would add to the knowledge base of the host compound’s preferences and selectivities. In a separate study, TETROL and its derivative, (–)-(2R,3R)-2,3-dimethoxy-1,1,4,4- tetraphenylbutane-1,4-diol (DMT), were also allowed to compete for the inclusion of the guest cyclohexanone, where TETROL demonstrated superior ability. This host, in addition, showed potential for the separation of cis- and trans- 2-methylcyclohexanol.]]> Thu 13 May 2021 01:55:11 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10599 Thu 13 May 2021 01:38:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26866 Thu 13 May 2021 01:38:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10643 Thu 13 May 2021 01:30:41 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10582 Thu 13 May 2021 01:30:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10644 Thu 13 May 2021 01:26:10 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:27803 Thu 13 May 2021 01:10:29 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10529 Thu 13 May 2021 01:07:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10355 Thu 13 May 2021 01:04:00 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:34277 Thu 13 May 2021 01:03:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10363 Thu 13 May 2021 01:01:02 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10655 2 km) and Congo (>200 m) are linked to interactions between the lithosphere and mantle geodynamics, and how these processes likely affected global climate changes.]]> Thu 13 May 2021 00:52:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10390 Thu 13 May 2021 00:47:05 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10542 Thu 13 May 2021 00:41:15 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10518 Thu 13 May 2021 00:39:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10519 Thu 13 May 2021 00:38:22 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:10483 Thu 13 May 2021 00:30:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:11088 Thu 13 May 2021 00:28:23 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10621 20 μm) accounted for > 65 percent of the Chl a, whereas during closed mouth conditions they accounted for about 55 percent of the Chl a biomass. Chlorophytes became the dominant taxon in the dry summer months but were replaced by cryptophytes and dinoflagellates during the wet season. When nutrient concentrations were low during low flow conditions in the Van Stadens Estuary mixotrophic microphytoplankton became an important fraction of the water column together with phototrophic dinoflagellates and cryptophytes. In the Maitland large sized chlorophytes were the dominant taxa in late spring and summer seasons and made up more than 80 percent of the cell numbers. In the Maitland before the floods in 2002 cyanophytes were the dominant group in late spring contributing more than 75 percent in cell abundance. Data from the short-term study in the Van Stadens Estuary showed similarities and differences in the Chl a response to increased river inflow. High river inflow initially reduced Chl a biomass followed by a recovery period of a couple of days compared to a 8 – 10 week recovery period in studies monitored over seasonal and annual temporal scales. The responses may be dissimilar but help to illustrate that there are similar response patterns to environmental forcing necessary to support phytoplankton biomass at different temporal scales. This study has demonstrated that flooding events caused by strong river flow cause breaching of the mouth, a reduction in salinity and marked nutrient input. Although the causes of flooding can be similar in both estuaries the resultant effects are varied and can alter the ability of the estuary to retain water. This study was able to demonstrate that the supply of macronutrients from the catchment was strongly correlated with rainfall (R2 = 0.67) and that phytoplankton growth mainly depended on an allochthonous source of macronutrients although internal supplies could be critical at times in controlling microalgal biomass.]]> Thu 13 May 2021 00:22:20 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:26889 Thu 13 May 2021 00:09:50 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:29314 Mon 22 Aug 2022 14:58:54 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:28280 Fri 15 Mar 2024 08:55:07 SAST ]]>