A new and earlier record of Chrysomya megacephala in South Africa, with notes on another exotic species, Calliphora vicina (Diptera Calliphoridae)
- Authors: Williams, Kirstin A , Villet, Martin H
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440710 , vital:73805 , https://hdl.handle.net/10520/EJC84554
- Description: South African records of Chrysomya megacephala and Calliphora vicina are reviewed and plotted on maps. Dispersal routes of these two forensically and medically important blowfly species are discussed. Emphasised is the importance of deposition of voucher material in museum collections.
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- Date Issued: 2006
AmaNdebele, Peter Magubane and Sandra Klopper: book review
- Authors: Simbao, Ruth K
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147336 , vital:38627 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC31002
- Description: AmaNdebele is a very attractive book with beautifully reproduced colour photographs taken by the renowned photographer Peter Magubane, who secured enormous credibility as a photojournalist during the violent years of apartheid. While some South African readers who browse through the glossy portrayals of ceremonial attire and homestead decorations may recall Magubane's earlier books such as Soweto speaks (1981) and Soweto: The fruit of fear (1986) in which the photographer laid bare the ferocious violence of apartheid rule, many readers will skip over the nuances of both Magubane's disrupted career and the contentious relationship between the Ndebele people and the South African apartheid government.
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- Date Issued: 2006
Doing the twist: a test of Darwin's cross-pollination hypothesis for pollinarium reconfiguration
- Authors: Peter, Craig I , Johnson, Steven D
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6534 , http://hdl.handle.net/10962/d1005975
- Description: Mating success in plants depends largely on the efficiency of pollen dispersal. For hermaphrodite plants, self-pollination, either within or among flowers, can reduce mating opportunities because of pollen and ovule discounting and inbreeding depression. Self-pollination may be particularly detrimental in plants such as orchids and asclepiads that package each flower’s pollen into one or more pollinia which, together with accessory structures, comprise a pollinarium. Darwin proposed that physical reconfiguration of pollinaria serves as a mechanism for reducing the likelihood of self-pollination. To be effective, the time taken for pollinarium reconfiguration would need to exceed that spent by a pollinator on a plant. We investigated pollinarium reconfiguration (including pollinarium bending, pollinium shrinking and anther cap retention) in 19 species and found a strong positive relationship between reconfiguration time and the duration of pollinator visits. Reconfiguration times were also consistently longer than pollinator visit times. These results provide strong support for Darwin’s idea that this mechanism promotes cross-pollination. , Elsevier
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- Date Issued: 2006
Effects of prophylactic progesterone in decomposing tissues on the development of Chrysomya chloropyga (Wiedeman)(Diptera Calliphoridae)
- Authors: da Silva, C , Villet, Martin H
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442020 , vital:73950 , https://hdl.handle.net/10520/EJC32654
- Description: Medico-legal forensic entomology is often concerned with the estimation of postmortem intervals (PMI), the time elapsed since the death of a body, by estimating the age of maggots if they are found on a body. These estimates can be complicated by the presence of a variety of drugs that may be present in dead bodies, including steroids such as hydrocortisone (Musvasva et al. 2001).
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- Date Issued: 2006
Inetvis, a visual tool for network telescope traffic analysis
- Authors: van Riel, Jean-Pierre , Irwin, Barry V W
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430176 , vital:72671 , https://doi.org/10.1145/1108590.1108604
- Description: This article illustrates the merits of visual analysis as it presents prelimi-nary findings using InetVis - an animated 3-D scatter plot visualization of network events. The concepts and features of InetVis are evaluated with reference to related work in the field. Tested against a network scanning tool, anticipated visual signs of port scanning and network mapping serve as a proof of concept. This research also unveils sub-stantial amounts of suspicious activity present in Internet traffic during August 2005, as captured by a class C network telescope. InetVis is found to have promising scalability whilst offering salient depictions of intrusive network activity.
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- Date Issued: 2006
Orthopaedic grade ultra–high molecular weight polyethylene: some features of the main thermoluminescence glow curve
- Authors: Chithambo, Makaiko L
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125499 , vital:35789 , https://doi.10.1093/rpd/nci661
- Description: Thermoluminescence (TL) characteristics of orthopaedic–grade ultra–high molecular weight polyethylene have been investigated between 20 and 200_C. The TL at 1_C s_1 consists of two glow curves, a weaker intensity peak at 115_C and the main peak at 70_C, studied in this work. TL intensity increases with beta irradiation but with a dose–response influenced by heating rate. On the other hand, the peak maximum is affected by both irradiation and repeated use of a sample. The glow curve shifts to higher temperatures with increase in heating rate but only slightly so with change in beta irradiation dose, properties suggestive of first-order kinetics. Kinetic analysis for activation energy and order of kinetics, based on the discrete trap model, produce somewhat conflicting results. Whereas qualitative analysis of peak symmetry show that first-order kinetics apply, geometrical analysis of the peak shape suggests that the order of kinetics might be other than first-order. Values of activation energy evaluated using the initial rise method were found to be dose dependent and for a given beta dose are in agreement with calculations from peak shape and initial rise methods but less so with results from variable heating rate method.
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- Date Issued: 2006
Variation in the timing of reproduction of the four-striped field mouse, Rhabdomys pumilio, in the Eastern Cape Province, South Africa
- Authors: Jackson, Claire , Bernard, Ric T F
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447101 , vital:74584 , https://doi.org/10.1080/15627020.2006.11407367
- Description: We used the four-striped field mouse, Rhabdomys pumilio (Sparrmann, 1784), to test the hypothesis that reproduction in a small, short-lived mammal will be opportunistic, characterized by temporal and spatial variation in the timing of events, and only be inhibited under harsh and predictable winter conditions. Field mice were trapped for three years in two regions of the Eastern Cape Province of South Africa, one that experienced a predictable and harsh winter (Mountain Zebra National Park; MZNP) and the other which experienced a milder winter (Thomas Baines Nature Reserve; TBNR). There was no winter inhibition of reproduction at TBNR, while at MZNP female reproductive activity was inhibited but males continued to produce spermatozoa in winter. We interpret this flexibility in the timing of reproduction as supporting an opportunistic reproductive strategy which may be an adaptation to the seasonal and often unpredictable climate of the region.
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- Date Issued: 2006
The reflection on peace agreements in Africa: feature
- Authors: Bischoff, Paul, 1954-
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/161398 , vital:40623
- Description: For Africa, the advent of globalisation, delivered in the shape of Structural Adjustment Programmes in the period from the early 1980s, ushered in the beginning of the end of the nation-building framework adopted at independence. Government's withdrawal from social, intellectual and economic areas of life brought into sharp relief the vulnerability of both state and society. Accompanied on the foreign policy front by a loss of Big Power protection after the Cold War ended, 'low and intrastate politics' came to the fore.
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- Date Issued: 2005
A new broom: feature
- Authors: Cocks, Michelle L , Dold, Anthony P , Sizane, Nomtunzi
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141404 , vital:37969 , https://hdl.handle.net/10520/EJC112779
- Description: Traditional grass brooms keep certain cultural practices alive in urban areas and provide rural people with a means to earn an income.
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- Date Issued: 2004
A yellowwood by any other name: molecular systematics and the taxonomy of Podocarpus and the Podocarpaceae in southern Africa
- Authors: Barker, Nigel P , Muller, E M , Mill, R R
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6495 , http://hdl.handle.net/10962/d1004488
- Description: We briefly review the taxonomic history of the Podocarpaceae, with an emphasis on the recognition of numerous segregate genera out of Podocarpus sensu lato. Despite some controversy over the recognition of these genera, molecular data (DNA sequences) provide evidence that supports this taxonomy. The implications for African Podocarpaceae are discussed. In particular, molecular data support the recognition of Afrocarpus as distinct from Podocarpus. Additional taxonomic problems concerning the possible segregation of Podocarpus milanjianus from P. latifolius are addressed using DNA sequence data from the nuclear internal transcribed spacer 2 (ITS2) region. Results of this are inconclusive, and suggest that alternative DNA-based evidence, such as from AFLPs or microsatellites, may be more informative in resolving such species complexes in African Podocarpus.
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- Date Issued: 2004
An interdisciplinary cruise dedicated to understanding ocean eddies upstream of the Prince Edward Islands
- Authors: Ansorge, Isabelle J , Froneman, P William , Lutjeharms, Johan R E , Bernard, Kim S , Lange, Louise , Lukáč, D , Backburg, B , Blake, Justin , Bland, S , Burls, N , Davies-Coleman, Michael T , Gerber, R , Gildenhuys, S , Hayes-Foley, P , Ludford, A , Manzoni, T , Robertson, E , Southey, D , Swart, S , Van Rensburg, D , Wynne, S
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6830 , http://hdl.handle.net/10962/d1007566
- Description: A detailed hydrographic and biological survey was carried out in the region of the South-West Indian Ridge during April 2004. Altimetry and hydrographic data have identified this region as an area of high flow variability. Hydrographic data revealed that here the Subantarctic Polar Front (SAF) and Antarctic Polar Front (APF) converge to form a highly intense frontal system. Water masses identified during the survey showed a distinct separation in properties between the northwestern and southeastern corners. In the north-west, water masses were distinctly Subantarctic (>8.5°C, salinity >34.2), suggesting that the SAF lay extremely far to the south. In the southeast corner water masses were typical of the Antarctic zone, showing a distinct subsurface temperature minimum of <2.5°C. Total integrated chl-a concentration during the survey ranged from 4.15 to 22.81 mg chl-a m[superscript (-2)], with the highest concentrations recorded at stations occupied in the frontal region. These data suggest that the region of the South-West Indian Ridge represents not only an area of elevated biological activity but also acts as a strong biogeographic barrier to the spatial distribution of zooplankton.
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- Date Issued: 2004
Concerning secondary thermoluminescence peaks in α-Al_2_O_3_:C
- Authors: Chithambo, Makaiko L
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6793 , http://hdl.handle.net/10962/d1003823
- Description: Thermoluminescence characteristics of two subsidiary glow peaks, one below 100°C and the other above 300°C, have been studied for measurements between 30°C and 500°C in α-Al_2_O_3_:C. The thermoluminescence intensity of the lower temperature peak decreased with storage with a half-life of about 150 s. In contrast, the intensity of the higher temperature peak increased with storage towards some maximum. The peak-temperature of each of the secondary glow peaks was essentially constant with dose, whereas that of the main peak decreased with irradiation. The dose response for the three peaks was similar except for sublinear growth in the higher temperature peak at low dose values. These effects are discussed in terms of changes in the concentration of F+ luminescence precursors brought about by competitive electron retrapping at deep electron-traps or hole-traps. This work refines the physics and application of α-Al_2_O_3_:C luminescence in radiation dosimetry.
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- Date Issued: 2004
Drimia chalumnensis (Hyacinthaceae - Urgineoideae), a new species from Eastern Cape, South Africa
- Authors: Dold, Anthony P , Brink, Estelle
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6516 , http://hdl.handle.net/10962/d1005944
- Description: Drimia chalumnensis, a new inconspicuous dwarf species from the Albany Centre of Floristic Endemism in Eastern Cape, South Africa, is restricted to the coastal plains of the Chalumna river in small scattered aggregated colonies on exposed sandstone sheets in pockets of loose sandy soil. It is distinguished by its capitate inflorescence, separate, petiolate bulb scales, and prostrate, coriaceous, linear-lanceolate leaves with cartilaginous margins.
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- Date Issued: 2004
Isolation of genes encoding heat shock protein 70 (hsp70s) from the coelacanth, Latimeria chalumnae
- Authors: Modisakeng, Keoagile W , Dorrington, Rosemary A , Blatch, Gregory L
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6459 , http://hdl.handle.net/10962/d1005788
- Description: Under stress conditions, proteins unfold or misfold, leading to the formation of aggregates. Molecular chaperones can be defined as proteins that facilitate the correct folding of other proteins, so that they attain a stable tertiary structure. In addition, they promote the refolding and degradation of denatured proteins after cellular stress. Heat shock proteins form one of the main classes of molecular chaperones. We are interested in determining if the genome of the coelacanth (Latimeria chalumnae) encodes a heat shock protein-based cytoprotection mechanism. We have isolated 50 kb and larger coelacanth genomic DNA from frozen skin tissue of L. chalumnae. From the alignments of several fish Hsp70 proteins, conserved regions at the N- and C-termini were identified. Codon usage tables were constructed from published coelacanth genes and degenerate primers were designed to isolate the full-length hsp70 gene and regions encoding the ATPase and the peptide binding domains. Since it is known that the tilapia and Fugu inducible hsp70 genes are intronless, we proceeded on the assumption that a coelacanth inducible hsp70 would also be intronless. A large fragment (1840 bp) encoding most of a coelacanth Hsp70 protein, and two partial fragments encoding a coelacanth Hsp70ATPase domain (1048 bp) and peptide binding domain (873 bp), were isolated by polymerase chain reaction amplification. Protein sequences translated from all the nucleotide sequences were closely identical to typical Hsp70s. This is the first study to provide evidence for a cytoprotection mechanism in the coelacanth involving an inducible Hsp70.
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- Date Issued: 2004
Quantification of the photosynthetic performance of phosphorus-deficient Sorghum by means of chlorophyll-a fluorescence kinetics
- Authors: Ripley, Bradford S , Redfern, S P , Dames, Joanna F
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6456 , http://hdl.handle.net/10962/d1004464
- Description: Chlorophyll fluorescence induction curves have been used as a sensitive tool for screening the photosynthetic performance of plants. Experimental treatments involving nitrate supply and chilling stress have been shown to affect fluorescence induction curves and other measures of photosynthesis. We have investigated the photosynthetic performance of Sorghum bicolor supplied with Long Ashton growth solution containing standard (20 μmol mol^(–1)) or low (5 μmol mol^(–1)) phosphorus. The JIP-test based on the chlorophyll fluorescence induction curve was used as a non-destructive method to measure the relative proportions of energy dissipated by different processes (termed energy fluxes) in the light reactions. The various energy fluxes or derived parameters were compared to find the measures that were most sensitive to the experimental conditions. Plant response to treatments was first evident in selected chlorophyll fluorescence parameters, particularly performance index (PI_ABS_); plants with increased PI_ABS_ manifested higher electron transport activity and dissipated less energy as heat, possibly as a result of their better phosphorus status, leading to more functional reaction centres. Observed changes in fluorescence were correlated to changes in gas exchange and biomass. Standard phosphorus treatments significantly increased biomass, leaf area, photosynthetic and respiratory rates, carboxylation efficiencies and levels of ribulose biphosphate regeneration rates, relative to plants with low supplies of nutrients.
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- Date Issued: 2004
The Baylis-Hillman entrée to heterocyclic systems — the Rhodes contribution
- Authors: Kaye, Perry T
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6575 , http://hdl.handle.net/10962/d1004138
- Description: This review focuses on applications of the Baylis-Hillman reaction in the synthesis of various heterocyclic products, which include indolizines, chromenes, thiochromenes, coumarins and quinolines. Attention is also given to the mechanistic implications and the elaboration of various products to afford compounds with medicinal potential.
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- Date Issued: 2004
Using visuals to communicate medicine information to patients with low literacy:
- Authors: Dowse, Roslind
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156958 , vital:40073 , https://journals.sagepub.com/doi/pdf/10.1177/104515950401500106
- Description: The patient was adamant that she had taken her medicine as instructed, pointing to the visual (Visual 1) illustrating the instructions to endorse this. Via an interpreter, she communicated that she took her tablet three times during the day and once at night (which was correct), but only on those days when the sun was shining (not on cloudy days) and the moon was visible (depending on both cloud cover and phases of the moon).
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- Date Issued: 2004
Women and Water: How is Gender Policy Working on the Ground The Water Wheel
- Authors: Berold, Robert
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/437684 , vital:73402 , ISBN report , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/WW_04_mar-apr_WiW.pdf
- Description: The gender policy of the Department of Water Affairs and Forestry (DWAF), formu-lated in 1997, was designed to promote gender equality both within DWAF itself and in its activities at community level. The policy required a quota of at least 30% (since increased to 50%) of women in all decision-making committees as well as adequate participation and technical training. How does the policy work out in the rural areas, far away from DWAF head office in Pretoria? The Water Research Commission (WRC) conducted a research study in the Peddie area to find out. Fort Hare lecturer Priscilla Monyai looked at four villages close to the town of Peddie in the densely populated former Ciskei, between Grahamstown and King Williams Town. About 4 000 people live in the villages of Cisira, Ncala, Nqwenerana and Mgwangqa. All get their water from the Peddie water supply scheme which began supplying clean drinking water in 1999.
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- Date Issued: 2004
A Performance Comparison of Web Development Technologies to Distribute Multimedia across an Intranet
- Authors: Swales, D , Sewry, David , Terzoli, Alfredo
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427501 , vital:72443 , https://www.researchgate.net/profile/Alfredo-Ter-zoli/publication/237337386_A_Performance_Comparison_of_Web_Development_Technologies_to_Distribute_Multimedia_across_an_Intranet/links/0c9605298fdf33d7c0000000/A-Performance-Comparison-of-Web-Development-Technologies-to-Distribute-Multimedia-across-an-Intranet.pdf
- Description: In recent years the World Wide Web has transformed into a dynamic, interactive medium, exposing a proliferation of on-line services that dis-tribute large quantities of multimedia. This has increased awareness of the need to select an appropriate Web programming technology when creating Webbased services. This paper compares three dynamic Web programming technologies from the point of view of performance in multimedia distribution. In particular, this paper examines Sun Microsys-tem’s Java Server Pages (JSP), Microsoft’s Active Server Page’s (ASP) and the more recent ASP .NET. The comparison is based on testing applications that distribute multiple images from an Oracle 9i database to Web-enabled clients. Previous research conducted by Oracle indi-cates that JSP and the underlying Java platform outperform ASP. The results in this paper, however, do not agree with Oracle’s statement as JSP tends to be marginally slower than ASP.
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- Date Issued: 2003
Editorial: the policy-in-practice nexus
- Authors: Lotz-Sisitka, Heila , Obol, Charles , Nhamo, Godwell
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67389 , vital:29083 , https://www.ajol.info/index.php/sajee/article/view/122661/112205
- Description: publisher version , Environmental policy development and implementation has become a ‘hot topic’ in southern Africa, following global imperatives for countries around the world to articulate their intentions to become more sustainable through public policy. Many policies in the region have been developed with the support of large scale donor funding. Much of the funding is often allocated to policy development processes rather than policy implementation processes, and many countries have experienced ‘gaps’ between policy intention and policy playing out in the field. Recently the Southern African Development Community’s Regional Environmental Education Programme (SADC REEP) appointed an environmental education policy advisor to influence regional policy (our Guest Editor, Charles Obol).This edition of the journal, funded by SADC REEP, aims to provide perspective on the policy-in-practice nexus in southern Africa.
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- Date Issued: 2003