53 research outputs found
William (Wil) Vosloo - 'n Bybel-wetensakplike wat die Ou Testament vir die volk wou oopbreek
No full textWilliam (WiJ) Vosloo - A Biblical scholar who exposes the Old Testament for ordinary people W Vosloo (1934- ) is one of the fine Old Testament scholars in South Africa. His work on the exposition and understanding of the Bible in general, and on the Old Testament in particular, counts to the core contributions of Biblical Studies in South Africa the last two decades. This short portrait sketches Vosloo as a man of mature character and life experience. With his exposition of biblical texts, his aim was to serve the church. At university level he was a dedicated academician and lecturer. He will also be remembered as a theologian and author of stature. William Vosloo was in his professional career really a human being for fellow humans
William (Wil) Vosloo - A biblical scholar who exposes the Old Testament for ordinary people
No full textW Vosloo (1934- ) is one of the fine Old Testament scholars in South Africa. His work on the exposition and understanding of the Bible in
general, and on the Old Testament in particular, counts to the core contributions of Biblical Studies in South Africa the last two decades.
This short portrait sketches Vosloo as a man of mature character and life experience. With his exposition of biblical texts, his aim was to serve
the church. At university level he was a dedicated academician and lecturer. He will also be remembered as a theologian and author of
stature. William Vosloo was in his professional career really a human being for fellow humans
Evaluating the thermal stress response of South African abalone, Haliotis midae, to biogeographical temperature variability.
No full textM.Sc. University of KwaZulu-Natal, Durban 2014.A gradient of sea temperatures is created along the South African coastline by the confluence of the cold Benguela Current on the West coast with the warm Agulhas Current on the East coast. This temperature gradient allows for an assortment of species to occupy the variety of microenvironments occurring in this area. Amongst these species is commercially important South African abalone, Haliotis midae, which although being capable of existing across this wide range of temperatures grows larger on the cooler West coast. Abalone reared on the warmer East coast however, experience greater mortalities especially during the more thermally variable summer months. The aim of the study was thus to assess the zone of tolerance for H. midae by exposing abalone to fluctuating temperatures in an attempt to model environmental temperature instability, a scenario which may likely be worsened by global climate change.
Animals from the West and East coasts were exposed to two thermal treatments of fluctuating temperatures with the first group being kept at 16°C±2 and the second group kept at 16°C±4. The control group was maintained at a constant 16°C indicating that the mean temperature experienced by all three groups was 16°C. Oxygen consumption, nitrogen excretion and O:N ratio were assessed at the organismal level to give an indication of metabolic rate, amount of protein excreted and type of metabolic substrate utilized respectively. At the biochemical level, D-lactate accumulation was quantified to indicate whether metabolism was proceeding aerobically or anaerobically. Heat shock protein 70 (Hsp70) expression and degree of carbonylation were analyzed at the proteomic level with Hsp70 also being assessed at the transcriptomic level. All biological responses were measured at days 1, 3, 7 and 14 of the two week exposure.
Oxygen consumption rates were significantly elevated on day 14 when comparing treatment group animals to control group animals of the same biogeographic region. P < 0.05 for both treatment groups from the West coast, while P < 0.001 for the East coast treatment groups. The ammonia excretion rates of the West coast animals were significantly lower than those of the controls at day 14 with P < 0.001 for both treatment groups, while ammonia excretion rates were elevated in East coast animals at day 14, although not significantly. Trends similar to those seen for ammonia excretion rates were exhibited by O:N ratios. West coast animals showed lower than control O:N ratios at day 14 (P < 0.01 for both treatment groups) while East coast animals displayed higher than control values (P < 0.05 only for the 16°C±2 group) at day 14. D-lactate, having been detected only for the West coast animals, showed no significant differences but large degrees of variation were noted on days 1 and 7. Carbonylation was evident for animals from both biogeographic regions with baseline carbonyl accumulation for East coast animals being greater (non-significantly) than that of the West coast animals. The hsp70 gene expression remained low for both biogeographic groups with West coast animals appearing to show slight elevations in expression at days 1 and 7, days which also displayed high degrees of variability.
The West coast animals appeared to be better suited to coping with the thermal fluctuations, as they not only transiently reduced oxygen consumption rate to reduce ROS production, but also utilized the assistance of the D-lactate pathway possibly to maintain metabolism, both of which were not observed in the East coast animals. Although West coast abalone seemed to have slightly elevated hsp70 expression (suggestive of a repair response) when compared to their East counterparts, both groups of abalone were shown to have incurred notable amounts of protein damage (i.e. carbonylation). This suggests impairments in both protective and repair responses for animals from both biogeographic regions. The lack or attenuation of physiological responses noted in East coast abalone may be due to limitations in thermal adaptation but subsequent studies are required to confirm this notion.
The information obtained from this study may assist in providing an insight into the mechanisms responsible for thermal limitation in H. midae and how this species is likely to respond to future periods of thermal instability which may be worsened by global climate change. An understanding of the processes leading up to limitations may potentially assist the abalone aquaculture industry in altering culturing practices early on to support optimal performance in abalone
Flight calls and orientation:A pilot study
No full text In a pilot experiment a European Robin, Erithacus rubecula, expressing migratory restlessness with a stable orientation, was video filmed in the dark with an infrared camera and its directional migratory activity was recorded. The flight overhead of migrating conspecifics uttering nocturnal flight calls was simulated by sequential computer controlled activation of five loudspeakers placed in a linear array perpendicular to the bird's migration course. The bird responded to this stimulation by changing its migratory course in the direction of that of the ‘flying conspecifics' but after about 30 minutes it drifted back to its original migration course. The results suggest that songbirds migrating alone at night can use the flight calls from conspecifics as additional cues for orientation and that they may compare this information with other cues to decide what course to keep. </p
Flight calls and orientation:A pilot study
No full text In a pilot experiment a European Robin, Erithacus rubecula, expressing migratory restlessness with a stable orientation, was video filmed in the dark with an infrared camera and its directional migratory activity was recorded. The flight overhead of migrating conspecifics uttering nocturnal flight calls was simulated by sequential computer controlled activation of five loudspeakers placed in a linear array perpendicular to the bird's migration course. The bird responded to this stimulation by changing its migratory course in the direction of that of the ‘flying conspecifics' but after about 30 minutes it drifted back to its original migration course. The results suggest that songbirds migrating alone at night can use the flight calls from conspecifics as additional cues for orientation and that they may compare this information with other cues to decide what course to keep. </p
The use of biological indices to assess the water quality of the Vaal River with specific reference to the Vredefort Dome area
No full textMSc (Environmental Sciences), North-West University, Potchefstroom CampusWater is one of South Africa's most limited resources and the Vaal River, as one
of the country's hardest working rivers, provides water to a considerable
proportion of the country's agricultural, industrial and household needs.
The Vredefort Dome, one of the biggest meteorite impact sites on earth, is of
great ecological significance. It maintains a unique ecosystem of biota that
significantly differs from the surrounding area. The area has been proposed to
receive World Heritage status, and has potential as an eco-tourism destination.
From October 2001 - August 2002 the quality of the Vaal River in the Vredefort
Dome was assessed with biological indices. SASS 5, IHAS and physical-chemical analysis were conducted along the Vaal River within the Vredefort
Dome.
From the results, it was evident that good to fair water quality prevailed in the
Vredefort dome. The SASS and ASPT scores were in the fair to good range, and
the number of taxa fell into the good to excellent range, indicating good overall
river health. Seasonal patterns in the occurrence of macroinvertebrates were
observed for this section of the Vaal River. Habitat scores were generally in the
fair range, indicating adequate habitat conditions. The results of the
physical/chemical analysis did not show any significant problems. The
geomorphology of the Dome indicates a big slope between the first and last site,
averaging a drop of 1.96m.km-1. Preliminary investigations into the occurrence of
freshwater molluscs in the Vredefort Dome indicated the distribution of molluscs
in the area. Problems encountered in the Dome area were of aesthetical
importance, resulting from a high degree of eutrophication.
More sampling is advised before any management proposals for the Dome area
could be made. It is advisable that this area should be subjected to routine
sampling to spot potential water quality problems as soon as possible.Master
Utilization of dried blood spots for assessing dusky kob (Argyrosomus japonicus) glycaemia and metabolome in South African aquaculture.
No full textMaster of Science in Biological Sciences. University of KwaZulu-Natal, Durban, 2017.Dusky kob (Argyrosomus japonicus) is an important marine fish in South African aquaculture, and has the potential to become commercially significant. The continuous growth of Dusky kob culture faces challenges with regards to fish health. There is currently a lack of on-farm tools for fish health assessment and Dusky kob are known to be prone to parasitic infections.
Fish blood glucose is a reliable indicator of biological and environmental stress; however, methods of glycaemia diagnosis are often lab based and cannot be conducted rapidly. This limits the use of glucose to assess the condition of fish on-site. Furthermore, the gill parasite Diplectanum oliveri continuously affects Dusky kob and the only know method of detection is microscopic analysis which requires destructive sampling. The drawbacks of fish health assessment are further amplified by the lack of reliable methods of sample collection, storage and transportation.
Conventional methods of blood sample collection have limitations, including complex protocols (collection and storage), sample degradation during storage and large volumes required for analysis. Additionally, blood samples (plasma, serum and whole blood) are often restricted to single use due to sample degradation, thus do not allow for repeated analysis. Dried blood spots (DBS) offer an alternative method of sample collection, with benefits including ease of use (collection and handling), storage and transportation. Furthermore, DBS require relatively small volumes and ensure sample integrity is maintained due to the elimination of a liquid medium thus inhibiting metabolic reactions. DBS further allow for repeated analyses across a wide range of blood parameters and numerous assays. The use of DBS is currently limited to human health research, however, can be beneficial in fish health assessment and biomarker discovery in aquaculture.
In the present study, the utility of DBS as (1) a reliable method of blood collection and (2) an effective medium for biomarker discovery in fish was investigated. Dusky kob DBS were collected from four farms namely; Mtunzini Fish Farm (currently Zini Fish Farms, KwaZulu-Natal), Oceanwise (currently Ocean Choice), Pure Ocean (both Eastern Cape) and Blue Cap (Western Cape) fish farms between February – May 2015. The use of a hand-held diabetic glucometer as a reliable tool for on farm glucose measurement
tested against laboratory based enzymatic analyses of DBS, plasma and whole blood. Lastly, the application of metabolomics analyses of Dusky kob DBS was examined as a potential for a non-destructive alternative method for the detection of parasitic infections.
A consistent over-estimation of glucose by DBS was observed, while the use of a diabetic glucometer was shown to be a reliable tool for on-farm glucose measurements. The accuracy of the glucometer was evident by the correlation with plasma glucose (R2 = 0.973). Plasma is the recommended medium for glucose analysis since the removal of red blood cells inhibits glycolysis. Additionally, targeted metabolomic analysis of DBS by LC-MS and GC-MS identified 53 metabolites. Six amino acids (citrulline, glutamine, lysine, methionine, phenylalanine and proline) were significantly altered in accordance to parasite intensities and/or geographical distributions.
The results indicate that hand-held glucometers can be used on-farm for accurate preliminary measures of glucose, which is further beneficial for rapidity and routine analysis. Continuous measurement of glucose can aid in detecting hyper- or hypoglycaemia. The ease of use provided by DBS is essential for biomarker discovery and fish health assessment. In addition to simple storage and transportation, DBS also ensure the stability of blood parameters including metabolites. Metabolomics analysis offer an essential platform for the early detection of parasites infecting farmed fish and eliminates the need for destructive sampling. The examination of metabolites reveals compounds that are essential in the innate and adaptive immune response of fish during infection. Understanding the roles of these compounds can be used to develop and implement corrective measures
Impact of turbidity on pseudodiaptomus stuhlmanni, a dominant copepod in Lake St Lucia, iSimangaliso Wetland Park.
No full textM. Sc. University of KwaZulu-Natal, Durban 2015.Although the St Lucia Estuary is a Ramsar Wetland of International Importance, it has historically been subjected to human-accelerated ecological stressors. One of these is high turbidity resulting from excessive sediment inputs. Laboratory-based studies have revealed a negative turbidity effect on the feeding and mortality rate of two dominant zooplankton species, the mysid Mesopodopsis africana and the calanoid copepod Acartiella natalensis. The first aim of this study was to determine the effect of turbidity on the feeding, respiration, and mortality rate of another important calanoid, Pseudodiaptomus stuhlmanni. Although this species was negatively affected by high turbidity, it was substantially more tolerant than M. africana and A. natalensis. The second aim was to test the field response of the dominant St Lucia zooplankton to a silt plume-causing flood event that occurred in March 2014. As M. africana was not abundant in the system prior to this event, attention was paid to the copepods. The field response of A. natalensis and P. stuhlmanni were in good agreement with the findings from the laboratory-based experiments. The population of A. natalensis underwent an immediate, and sharp decline, whereas that of P. stuhlmanni only declined in April 2014, after a month of surviving in highly turbid waters. However, P. stuhlmanni also took longer to recover, but this may be attributed to the attachment of parasitic epibiotic ciliates to this species. Therefore, although to different degrees, turbidity negatively impacted the dominant St Lucia zooplankton species. Through its observed positive correlation with the parasitic ciliates, turbidity further suppressed the abundance of the most turbid-water tolerant species, P. stuhlmanni. The importance of carefully managing sediment loading in St Lucia is stressed, as the effect of turbidity on zooplankton likely has food web-wide consequences
Ciliate-zooplankton epibiosis in Lake St Lucia.
No full textDoctor of Philosophy in Life Sciences. University of KwaZulu-Natal, Durban, 2018.Epibiosis is a symbiotic association of two organisms in which one species (epibiont) uses the surface of another species (basibiont or host) as an attachment substrate. An increasing number of studies are revealing that epibionts have mainly deleterious effects on crustacean meso-zooplankton (hereafter referred to simply as zooplankton) hosts. In spite of its widespread occurrence, there are very few studies in Africa that address epibiosis in the aquatic environment, particularly involving zooplankton as hosts. Epibiotic ciliates are often found attached to zooplankton in the St Lucia Estuary, in northan KwaZulu-Natal, South Africa. St Lucia is the largest estuarine lake in Africa and is globally recognized for its ecological importance. A study was conducted in St Lucia between 2015 and 2017, with the aim of determining: the identity of the epibiotic ciliates; their species-specific association with the zooplankton of St Lucia; the effects they have on their hosts and the environmental conditions that promote their proliferation. Based on live observations and images obtained from protargol staining and scanning electron microscopy, the epibiotic ciliates in the St Lucia Estuary were identified as the peritrich sessilid Epistylis sp. (Chapter 1). The results of the experimental study in Chapter 2 were that Epistylis sp. is species-specific, attaching only to the dominant calanoid copepod Pseudodiaptomus stuhlmanni (mainly adults) and that this relationship is host density dependent. Another finding of Chapter 2 was that Epistylis sp. exerts a negative effect on the survivorship of heavily covered P. stuhlmanni. The results of Chapter 3 revealed a low RNA content and RNA:DNA ratio in epibiont-hosting P. stuhlmanni compared with their non-hosting counterparts, which implies a compromised nutritional status of epibiont-hosting copepods. Laboratory-based experiments detailed in Chapters 4 and 5 revealed that Epistylis sp. is: a) unaffected by temperature; and b) favoured by salinities below 20 and organically rich turbidity within the range 250–500 NTU. Results obtained from monthly field observations throughout 2016 (Chapter 6) showed no correlation of Epistylis sp. with these physico-chemical parameters and with the abundance of P. stuhlmanni. The latter result may be due to the uncharacteristically low abundance of the host P. stuhlmanni during the sampling period (January–December 2016). Overall, findings of this study suggest that peritrich epibionts can substantially and negatively affect host species and that they have a complex, context-dependent relationship with environmental conditions. The ecological implications of ciliate-zooplankton epibiosis in the St Lucia Estuary and in similar systems are discussed
055_Final Treatise_5 April 2013
No full textThe legitimate existence of the Project Management Profession in the South African construction industry needs to relate to positive project influence on the industry roleplayers. This study assessed the perceived lack of recognition and acceptance of
Project Management as a stand-alone profession relating to:
· Appointments of Project Managers being questioned due to a perceived lack of influence and impact on project success.
· Project Managers not being recognised as an integral part of the industry.
· Project Management not being perceived as having a unique and defined function.
Interviews were held with 23 industry role-players made up of clients, contractors and consultants. The interviews solicited input on the role-players’ perception and
experience related to the influence of Project Management over the past 10 years, not only on a list of success criteria relative to their own role in the industry, but also their perception of the influence on the other defined role-player groups. Included in the interview questionnaire was also a range of general questions to refine the
feedback and further test the hypotheses. The data were interpreted and analysed by comparing the feedback of the respondents as a combination and separately as groups. The results of the study indicate that:
· Project Management could be seen as a legitimate part of the industry;
· The industry role-players perceive Project Management as making an impact and having a growing influence on the industry;
· A specific but broad set of skills are required by Project Managers;
· The Project Management function cannot be fulfilled by other consultants, but there are project related criteria which should be considered before making a final judgment. These criteria relate to project size and complexity; and
· Project Management is currently perceived to be more related to a specific person’s skill than to a specific profession.
The study’s aim was to influence and inform the views of industry role-players on the appointment of a Project Manager in the construction industr
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