https://vital.seals.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://vital.seals.ac.za/vital/access/manager/Repository/vital:1163 Wed 30 Mar 2022 14:38:05 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9852 Wed 13 Mar 2024 10:42:24 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1681 Wed 12 May 2021 23:46:38 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1204 Wed 12 May 2021 23:41:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2874 Wed 12 May 2021 23:39:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10117 Wed 12 May 2021 23:36:48 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4192 Wed 12 May 2021 23:18:25 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1857 Wed 12 May 2021 23:13:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9350 Wed 12 May 2021 23:09:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3990 Wed 12 May 2021 22:59:27 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2934 Wed 12 May 2021 22:46:10 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5511 Wed 12 May 2021 22:45:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:965 Wed 12 May 2021 22:34:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9261 Wed 12 May 2021 22:30:46 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:817 Wed 12 May 2021 22:23:23 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3964 0.05]. These results imply that differences in the biosynthetic pathways for biomass accumulation in sibling strains play a significant role in the intraspecific variation observed in pollutant sensitivity, pollutant degradation, and enzyme production. Categorical analysis of intraspecific differences was assessed according to four criterions. These included growth, extracellular peroxidase activities, tolerance to toxic pollutants and the biodegradation of model pollutants. Sibling strains showing the most variable responses in three or more of the selective criterion were recommended for further studies. These strains include P. chrysosporium ME446, BS 2.52, BS 13, BS 17, BS 18, and BS 24. Interestingly, BS 2.52 (a dikaryotic strain generating from the crossing of two haploid progeny) showed significantly lower degradation capabilities than the wildtype parent strain ME446. The inherited variability observed between sibling strains is to be further explored through proteome and transcriptome analysis and genetic linkage studies aimed at describing the mechanisms or pathways conferring tolerance to or degradation of environmental pollutants. In examining fewer organisms at this next level, the number of replicates examined can be increased and thus the power of detection of experimental procedures improved, enabling the detection of multigenic traits amongst genetically related organisms. Growth was shown to play a significant role in the intraspecific differences detected in pollutant sensitivity and degradation between sibling strains. Little is known about the mechanism of growth and differentiation, or the role of differentiation in regulating the lignolytic activity in this organism. The membrane gradostat bioreactor and a unique plug-flow membrane bioreactor were evaluated as novel tools with which to further explore the relationship between secondary metabolism, pollutant degradation and biofilm development in sibling strains. High yield MnP production at levels as high as 1478.8 U.l-1 was achieved using a laboratory scale membrane gradostat bioreactor. Furthermore, extensive mycelial differentiation and tissue formation are reported for P. chrysosporium in both the membrane gradostat bioreactor and plug-flow membrane bioreactor. Intraspecific differences in the extent of this differentiation were observed in strains ME446, BS 13, BS 17 and BS 26 cultured using the membrane gradostat bioreactor, highlighting the potential of these techniques as a platform for future strain improvement strategies.]]> Wed 12 May 2021 22:17:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2936 Wed 12 May 2021 21:06:36 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4742 Wed 12 May 2021 20:27:36 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9732 Wed 12 May 2021 20:22:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5241 Wed 12 May 2021 20:14:05 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9558 Wed 12 May 2021 20:09:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:8548 Wed 12 May 2021 20:02:32 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:11038 Wed 12 May 2021 19:53:03 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:8551 Wed 12 May 2021 19:51:08 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5698 Wed 12 May 2021 19:49:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1034 Wed 12 May 2021 19:33:35 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9486 Wed 12 May 2021 18:59:33 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:8564 Wed 12 May 2021 18:54:59 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9262 Wed 12 May 2021 18:51:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3437 Wed 12 May 2021 18:46:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:8372 Wed 12 May 2021 18:22:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2852 Wed 12 May 2021 18:13:30 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:8549 Wed 12 May 2021 17:52:51 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1946 Wed 12 May 2021 17:51:55 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5831 Wed 12 May 2021 17:47:39 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:980 Wed 12 May 2021 17:40:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5243 1, it was asserted that both O. mossambicus and C. gariepinus were mortality-dominated and fairly heavily exploited. However, potential for sustainable exploitation existed since both species showed signs of resilience due short longevity and high rate of natural mortality. Given the limitation of simple exponential models of fish mortality and growth under the situation of seasonal fluctuation of water levels, a simple predictive hydroclimatic- fisheries model was developed. The model predicted the life-history and production parameters fairly accurately (0.53 ≤ r² ≥ 0.98, p ≤ 0.05), and showed that environmental and biological events in the floodplain significantly (0.43 ≤ r² ≥ 0.91, p ≤ 0.05) followed the periodic function of time (day-of-the-year), hence, strongly seasonal. In addition, the flood-pulse preceded all the major biological events, with predicted phase lags established at 55.6º for peak flood, 157.2º, 260.1º, 334.6º and 341.4º for condition factor for O. mossambicus, recruitment, spawning period for O. mossambicus and C. gariepinus, respectively. Therefore, it was recommended that water obstruction on the Shire River must ensure sufficient water flow during the peak flood and spawning period to allow flooding and inundation of the floodplain in order to create habitat favourable for spawning and feeding as well as improve recruitment.]]> Wed 12 May 2021 17:32:49 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9609 Wed 12 May 2021 17:31:11 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3970 Wed 12 May 2021 17:15:50 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:799 Wed 12 May 2021 17:15:40 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1943 Wed 12 May 2021 17:07:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:764 Wed 12 May 2021 17:04:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10925 Wed 12 May 2021 16:52:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2406 Wed 12 May 2021 16:51:31 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1170 Wed 12 May 2021 16:46:37 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1127 Wed 12 May 2021 16:33:56 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1947 Wed 12 May 2021 16:30:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9592 Wed 12 May 2021 16:28:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9380 Wed 12 May 2021 16:23:56 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3416 Wed 12 May 2021 16:08:51 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5315 0.05; n=150). Pigmented puerulus (p<0.05; n=566) and juveniles (p<0.05; n=3528) preferred structurally complex structures that provided better shelter such as crates, which were more sheltered from sea swells, compared to oyster bags. Among oyster rafts, pigmented puerulus and juveniles preferred occupying the sheltered and centred raft areas, which provided better protection from wave action, compared to exposed raft areas, which were exposed to the incoming swell. Puerulus and juvenile lobster appeared to recolonise adjacent bags and crates, and possibly migrate to the substrate and off the farm due to the disturbance of the habitat during harvesting. The booth crevice collector was more efficient in collecting puerulus possibly due to the high structurally complex habitat and the better shelter they provided compared to the hogshair collector. The occupation of structurally complex habitats by early benthic stages may be related to morphological changes associated with metamorphosis. Puerulus settlement peaked during early spring (August-September) and was related to low sea surface temperatures (12.3°C), strong south winds, and moderate swells in the week preceding settlement. These conditions are synonymous with the “spring upwelling” season of the Lüderitz upwelling cell in the central Benguela current region. Puerulus nutritional condition peaked during this period possibly due to high levels of planktonic food (due to high nutrients from upwelling) that was available to the late stage phyllosoma larvae further offshore. A “good” puerulus settlement year during 2000 was associated with lower than average SST (11.6°C) and strong south winds and was followed by “poor” puerulus settlement years during 2001 and 2002 when higher than average SST were experienced with below average wind speeds experienced during 2001 only. Puerulus of J. lalandii recruited in high numbers into Lüderitz Bay during the new moon, full moon and last quarter moon phases by making use of the increased tides during these phases of the lunar cycle. Peak juvenile abundance during early summer (November-December) lagged by 8 weeks was significantly correlated with peak puerulus abundance. Puerulus size was similar (8.5–9.7mm CL) over the study period. Juvenile cohorts, 9.9-20.6mm CL in size recruited in 2 distinct waves in August 2001-June 2002 and July 2002-February 2003. The 2001/2002 recruits had higher monthly growth increments and better nutritional condition compared to 2002/2003 recruits. Peak frequencies of 2nd moult juveniles (9.9- 10.8mm CL) occurred in September of both recruitment events with nutritional condition being poorest during the 2002/2003 event. The nutritional condition of the settling puerulus did not appear to be related to the subsequent growth of juvenile lobster. These preliminary results suggest that pueruli recruit once a year mainly during late winter/ early spring under conditions typical of coastal upwelling in the Benguela current near Lüderitz. It appears that puerulus settlement is driven by favourable shoreward currents, which help in transporting puerulus to their settlement grounds. Puerulus supply is highly variable between years, which appears to be consistent with a highly variable Benguela environment. The oyster farm supported a substantial standing stock averaging 123 800 lobster per day (range: 22 600-325 300 lobster per day) of which 26 600 were puerulus and 97 200 were juveniles, that may have been harvested once off on any given day during the sample period. Monthly harvesting of the total lobster standing stock during the one and a half year sampling period was just over 2 million lobsters (505 700 pueruli and 1.85 million juveniles) and would potentially have been sufficient seed for a 200 ton lobster production in puerulus lobster growout facilities. In the light of high inter-annual variation in puerulus settlement observed at Lüderitz, the seed supply at the Lüderitz oyster farm is clearly limited and therefore it is prudent that other sites of high puerulus settlement is established before large commercial scale lobster growout can commence. The migration of lobster off the farm suggested that these lobsters potentially recruit to the fishery and therefore harvesting the entire standing stock on the farm may have adverse negative effects on the wild fishery. A policy decision will be required as to whether more efficient harvesting of lobster from the farm should be allowed. If puerulus removal in J. lalandii for aquaculture is allowed in the near future, it should be conducted on an experimental scale or small commercial scale until the potential effects on recruitment into the fishery are clearer.]]> Wed 12 May 2021 16:07:37 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1650 Wed 12 May 2021 16:01:30 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3953 Wed 12 May 2021 15:53:29 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4256 Wed 12 May 2021 15:46:14 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9984 Thu 13 May 2021 16:27:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:8544 Thu 13 May 2021 13:15:23 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2988 Thu 13 May 2021 08:46:54 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4631 Thu 13 May 2021 08:16:07 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3439 Thu 13 May 2021 08:11:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3986 Thu 13 May 2021 08:03:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5832 Thu 13 May 2021 07:35:55 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5328 Thu 13 May 2021 07:25:33 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2006 Thu 13 May 2021 07:25:23 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3929 Thu 13 May 2021 07:14:41 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:948 Thu 13 May 2021 07:11:50 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:11017 Thu 13 May 2021 06:51:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:8536 Thu 13 May 2021 06:43:45 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1315 Thu 13 May 2021 06:39:27 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10977 Thu 13 May 2021 06:35:34 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:8539 Thu 13 May 2021 06:35:33 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1625 Thu 13 May 2021 06:20:56 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2938 Thu 13 May 2021 06:07:27 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5112 1800mm). The musculoskeletal responses indicated that Tall subjects were forced to adopt the most awkward general body postures as a result of the low computer screen. However, the low screen allowed for the Short subjects to adopt the most natural general body postures, although levels of muscular activity in the upper trapezius suggest that the muscular load imposed on both Short and Tall subjects was significantly greater than that imposed on the Medium subjects. In addition, the Medium subjects’ perceptions of the Standard workstation dimensions support the fact that this workstation was better suited to users with “average” morphologies. The responses elicited in the Personalised and Wrist Support workstations were improved significantly when compared to the Standard workstation. Joint angles were more natural, upper trapezius EMG was reduced, standard of performance improved and perceptual responses indicated a diminished incidence of body and visual discomfort, as well as greater perceived satisfaction with these workstation dimensions. The improved physical responses suggest a decrease in the risk of developing cumulative trauma disorders. Although subjects were unaccustomed to the wrist support device, this workstation demonstrated a further reduction in the range of wrist angles, as well as a general positive attitude towards the concept.]]> Thu 13 May 2021 05:56:42 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10166 Thu 13 May 2021 05:42:36 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:9376 Thu 13 May 2021 05:41:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3343 Thu 13 May 2021 05:29:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:8542 Thu 13 May 2021 05:06:39 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4746 Thu 13 May 2021 04:56:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3869 Thu 13 May 2021 04:37:15 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10924 Thu 13 May 2021 04:29:31 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5913 0.05). The multivariate analysis identified two interacting mechanisms controlling the distribution patterns, abundance and biomass of the various euphausiid species, namely (1) diel changes in abundance and biomass, (2) and restricted distribution patterns associated with the different water masses. Ingestion rates were determined for five euphausiid species. E. triacantha was found to have the highest daily ingestion rate ranging from 1 226.1 to 6 029.1 ng pigm ind⁻¹d⁻¹, while the lowest daily ingestion rates were observed in the juvenile Thysanoessa species (6.4 to 943.0 ng pigm ind⁻¹ d⁻¹). The total grazing impact of the selected euphausiids ranged from < 0.1 to 20.1 μg pigm m⁻²d⁻¹, corresponding to < 0.15 % of the areal chl-a biomass. The daily ration estimates of autotrophic carbon for the euphausiids suggested that phytoplankton represented a minor component in their diets, with only the sub-adult E. vallentini consuming sufficient phytoplankton to meet their daily carbon requirements. A cyclonic cold-core eddy spawned from the region of the APF located in the southwest Indian sector of the PFZ was the dominant feature during the 2005 survey. The total areal chl-a biomass throughout the region was low, ranging between 5.6 and 11.4 mg chl-a m⁻², and was significantly higher within the core of the eddy compared to the surrounding waters (p < 0.05). RMT-8 and WP-2 total euphausiid abundance and biomass estimates were high, and ranged from 0.004 to 0.36 ind m⁻³ and 0.065 to 1.21 mg dwt m⁻³, and from 0.01 to 18.2 ind m⁻³ and 0.01 to 15.7 mg dwt m⁻³, respectively. A distinct spatial pattern in the euphausiid community was evident with the Antarctic species, Euphausia frigida, E. triacantha and E. superba predominating within the core of the eddy, while the PFZ waters were characterized by the sub-Antarctic species, E. longirostris, Stylocheiron maximum, Nematoscelis megalops and Thysanoessa gregaria. The eddy edge acted as a transition zone where species from both regions co-occurred. Within the survey area the combined ingestion rate of the six numerically dominant euphausiid species ranged between 0.02 and 5.31 μg pigm m⁻²d¹, which corresponded to a loss of between < 0.001 and 0.11 % of the available chl-a biomass. E. triacantha and juvenile T. macura were identified as the dominant grazers. There was no apparent spatial pattern in the grazing activity of the euphausiids within the region of investigation. The average daily rations of the euphausiids examined were < 2 % of their body carbon. The low daily ration of the euphausiids could be ascribed to the predominance of small picophytoplankton in the region of investigation, which are too small to be grazed efficiently by larger zooplankton. The marked spatial patterns in species composition and the elevated abundance and biomass of euphausiids, suggest that the mesoscale eddies contribute to the spatial and temporal heterogeneity of the planktonic community of the PFZ and may represent important foraging regions for many of the apex predators within the region.]]> Thu 13 May 2021 04:21:56 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3163 Thu 13 May 2021 04:18:50 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9841 Thu 13 May 2021 04:06:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10764 Thu 13 May 2021 03:57:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1862 Thu 13 May 2021 02:52:35 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3247 Thu 13 May 2021 02:51:06 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3440 Thu 13 May 2021 02:29:17 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:8537 Thu 13 May 2021 02:17:23 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1634 Thu 13 May 2021 02:10:21 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4772 Thu 13 May 2021 02:09:29 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:8550 Thu 13 May 2021 01:38:32 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:950 Thu 13 May 2021 01:22:17 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4188 Thu 13 May 2021 01:17:07 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3446 Thu 13 May 2021 01:08:32 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2769 Thu 13 May 2021 01:02:51 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9487 Thu 13 May 2021 00:52:06 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9377 Thu 13 May 2021 00:47:27 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5651 Thu 13 May 2021 00:19:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1139 Thu 13 May 2021 00:12:51 SAST ]]>