The diet of the calanoid copepod, Pseudodiaptomus hessei, in a permanently open southern African estuary inferred from fatty acid analyses
- Authors: Noyon, Margaux , Froneman, P William
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70901 , vital:29758 , https://doi.org/10.1093/plankt/fbu037
- Description: The fatty acid (FA) composition of Pseudodiaptomus hessei, one of the most abundant copepod species in southern African estuaries and lakes, reveals potential food selectivity and the importance of flagellate prey in their diets. Differences in FA profiles between males and females were recorded; however, none of these patterns matched the reproductive activities of the copepod. Our findings stress the importance of improving our knowledge of FA biosynthesis pathways to employ fatty acids as trophic markers in feeding studies of zooplankton in temperate environments.
- Full Text:
- Date Issued: 2014
gpf: A GPU accelerated packet classification tool
- Authors: Nottingham, Alastair , Irwin, Barry V W
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428103 , vital:72486 , https://d1wqtxts1xzle7.cloudfront.net/67098560/gPF_A_GPU_Accelerated_Packet_Classificat20210505-17707-zqqa4s.pdf?1620201469=andresponse-content-disposi-tion=inline%3B+filename%3DgPF_A_GPU_Accelerated_Packet_Classificat.pdfandExpires=1714733902andSignature=NQ~1DjH1XOuqF8u1Yq74XyG7kp~y0II81vu40SuWO2GQhSgToTHC7ynbAoP3MGv9do~bX1PCAp2Z2TCKUVHT7CmYNRxDmnpk5G4kefH--0VotMHVtFnHnf5Q9nhrp0MIgSxEhncOrlRx5K5sRhlLkyfDib3RS8Y8vu~FIPvm1DaZrfqCZSpXKmHh9r1etybRBRtUokzayPtgbhE41bQtW9wI8J4-JTQ9doyNC-JflFuEfUnhv5Phf45lr7TALm8G8nGZBp3z9-nSLZDxls2mvvVIANCdutyOMDnMDadGoqjIB2wYwUy~Fm424ZWj7fF89Ytj9xqIU63H4NFE2HodtQ__andKey-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: This paper outlines the design of gPF, a fast packet classifier optimised for parallel execution on current generation commodity graphics hard-ware. Specifically, gPF leverages the potential for both the parallel classi-fication of packets at runtime, and the use of evolutionary mechanisms, in the form of a GP-GPU genetic algorithm to produce contextually opti-mised filter permutations in order to reduce redundancy and improve the per-packet throughput rate of the resultant filter program. This paper demonstrates that these optimisations have significant potential for im-proving packet classification speeds, particularly with regard to bulk pack-et processing and saturated network environments.
- Full Text:
- Date Issued: 2009
Advanced Personnel Psychology: IPS 602
- Authors: Nel, P , Van der Walt, R M
- Date: 2011-01
- Subjects: Psychology, Industrial
- Language: English
- Type: Examination paper
- Identifier: vital:17511 , http://hdl.handle.net/10353/d1010982
- Description: Advanced Personnel Psychology: IPS 602, special examination January 2011.
- Full Text: false
- Date Issued: 2011-01
A quantitative analysis of microplastic pollution along the south-eastern coastline of South Africa
- Authors: Nel, Holly A , Froneman, P William
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68032 , vital:29187 , https://doi.org/10.1016/j.marpolbul.2015.09.043
- Description: Publisher version , The extent of microplastic pollution (< 5 mm) in the southern hemisphere, particularly southern Africa, is largely unknown. This study aimed to evaluate microplastic pollution along the south-eastern coastline of South Africa, looking at whether bays are characterised by higher microplastic densities than open stretches of coastline in both beach sediment and surf-zone water. Microplastic (mean ± standard error) densities in the beach sediment ranged between 688.9 ± 348.2 and 3308 ± 1449 particles·m− 2, while those in the water column varied between 257.9 ± 53.36 and 1215 ± 276.7 particles·m− 3. With few exceptions there were no significant spatial patterns in either the sediment or water column microplastic densities; with little differences in density between bays and the open coast (P > 0.05). These data indicate that the presence of microplastics were not associated with proximity to land-based sources or population density, but rather is governed by water circulation.
- Full Text: false
- Date Issued: 2015
A Practical Approach to Differential Calculus: MAT 112
- Authors: Ndiweni, O
- Date: 2011-06
- Language: English
- Type: Examination paper
- Identifier: vital:17601 , http://hdl.handle.net/10353/d1009975
- Description: A Practical Approach to Differential Calculus: MAT 112, degree examination June 2011.
- Full Text: false
- Date Issued: 2011-06
Biological activity of plant extracts and isolated compounds from Alchornea laxiflora: Anti-HIV, antibacterial and cytotoxicity evaluation
- Authors: Ndinteh, Derek T , Olivier, D K , Noundou, Xavier S , Krause, Rui W M , Mnkandhla, D , Isaacs, Michelle , Hoppe, Heinrich C , Muganza, F M , Mbafor, J T , Van Vuuren, S F , Patnala, S
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126634 , vital:35907 , https://doi.org/10.1016/j.sajb.2018.08.010
- Description: This study was designed to assess the cytotoxicity, anti-HIV and antibacterial efficacy of various solvent extracts of roots, stem and leaves of Alchornea laxiflora, as well as five compounds isolated from its methanolic stem extract viz.; ellagic acid (1); 3-O-methyl-ellagic acid (2), 3-O-β-d-glucopyranosyl-β-sitosterol (3), 3-O-acetyl-oleanolic acid (4) and 3-O-acetyl-ursolic acid (5). The tested crude extracts were prepared from several solvent polarities including: hexane (Hex), chloroform (CHCl3), ethyl acetate (EtOAc), ethanol (EtOH), methanol (MeOH) and water (H2O). The anti-HIV properties were assessed on HIV-1 subtype C integrase while the cytotoxicity was tested against Hela cells. The antibacterial activity was studied on a panel of pathogens including gastrointestinal, skin, respiratory and urinary-tract infection causing Gram positive bacteria viz.; Bacillus cereus (ATCC 11778), Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 25923) and Staphylococcus saprophyticus (ATCC 15305)] and Gram-negative bacteria, i.e., Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 13883), Moraxella catarrhalis (ATCC 23246). All the tested samples were determined to be non-toxic due to the low inhibitions observed. The most potent anti-HIV activity was observed for the methanolic extract of A. laxiflora root (ALR4) with an IC50 value of 0.21 ng/ml, which was more active than chicoric acid used as reference drug (6.82 nM). Roots, stem and leaves of A. laxiflora extracts exhibited antibacterial activities against most of the Gram-positive bacteria with the minimum inhibitory concentrations (MIC) ranging between 50 and 63 μg/ml. Compounds 1–5 displayed antibacterial activities against S. saprophyticus with MIC values as low as 4 μg/ml. The results inferred from this study demonstrate the potential of A. laxiflora root as a source for new anti-HIV drugs and scientifically validate the traditional use of A. laxiflora in the treatment of gastrointestinal, skin, respiratory and urinary tract related infections. These results reaffirm the ethnopharmacological significance of African traditional medicines.
- Full Text:
- Date Issued: 2018
Towards the Development of a Photovoltaic Array Fault Detection and Diagnosis (PVAFDD) System
- Authors: Ncube, Prince D N , Meyer, Edson L , Shibeshi, Zelalem S
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429105 , vital:72560 , https://ieeexplore.ieee.org/abstract/document/9698581
- Description: The perpetual increment in energy demand continues to put pressure on the South African Economy. Independent Power Producers (IPPs) have been contracted to relieve the strain by supplementing energy production using solar photovoltaic (PV) technologies. These IPPs are paid per megawatt they produce and face stiff penalties should they fail to deliver on contractual obligations. Naturally solar PV plants are susceptible to numerous PV faults that could lead to a negative return on investment. It therefore makes economic sense to adopt mechanisms that can be able to detect, localize and diagnose PV faults when they occur within a solar PV system. There exists an extensive literature on how to detect and diagnose PV faults, however, localizing PV faults is still in its infancy. This paper proposes to cater to the needs of the IPPs by developing an intelligent PV Array Fault Detection and Diagnostics (PVAFDD) system capable of localizing PV faults which can be embedded into the Supervisory Control and Data Acquisition (SCADA) system used to manage and control such PV systems. The PVAFDD system is based on a machine learning (ML) model implemented using logistic regression algorithm. The ML model is trained using meteorological data ranging over a period of eight years in Alice, Eastern Cape. Using simulations driven by real-life data scenarios, we have been able to train, validate and test the PVAFDD system. When the PVAFDD system detects a fault, a cascade of real-time PVA tests is undertaken to localize the PV fault. The system then carries out PVA fault diagnostics and gives recommendations on the PV fault classification. Corrective measures can therefore be implemented on the affected PVA swiftly reducing the downtime of the PV plant, ergo proving to be a cost-effective measure that offers a competitive edge to IPPs using the PVAFDD system.
- Full Text:
- Date Issued: 2021
NUMSA’s bargaining process
- Authors: National Union of Metalworkers of South Africa
- Date: 19--?
- Subjects: Uncatalogued
- Language: eng
- Type: text , pamphlet
- Identifier: http://hdl.handle.net/10962/104517 , vital:32394
- Full Text:
- Date Issued: 19--?
Report back from Workers College School for Trade Union Women, 20-30 October 1998
- Authors: National Union of Metalworkers of South Africa
- Date: 1998-10-20
- Subjects: Uncatalogued
- Language: eng
- Type: text , pamphlet
- Identifier: http://hdl.handle.net/10962/104907 , vital:32443
- Full Text:
- Date Issued: 1998-10-20
Insecticidal activities and chemical composition of the essential oil from Tarchonanthus camphoratus (L.), leaves against Sitophilus zeamais Motschulsky, and Sitophilus oryzae (L.)
- Authors: Nanyonga, Sarah K , Opoku, Andy R , Lewu, Francis B , Oyedeji, Adebola O
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/711 , vital:29660
- Description: The essential oil of Tarchonanthus camphoratus dry leaves growing in Kwa-Zulu Natal, South Africa was obtained by hydrodistillation and evaluated for its repellent effect, contact and fumigation toxicity against both Sitophilus zeamais and Sarocladium oryzae. Chemical composition of the essential oil was analysed by gas chromatography mass spectrometry (GC/MS). The study revealed that the essential oil of T. camphoratus had no contact and fumigation toxicity against stored insect pests, S. zeamais and S. oryzae. The oil, however, showed good repellent activity of over 50% after 24 h for all the concentrations used on both S. zeamais and S. oryzae. A total of 27 compounds accounting for 73% of the total oil composition were identified of which sesquiterpene hydrocarbons, (59.18%), were the most dominant. These results suggest that the essential oil of T. camphoratus could be considered a potential control agent of stored grain pests as a repellent.
- Full Text:
- Date Issued: 2015
Policy Memo - Renegotiating the SACU agreement
- Authors: NALEDI
- Date: 1995
- Subjects: NALEDI
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/151381 , vital:39062
- Description: South Africa is in the process of renegotiating the Southern African Customs Union Agreement with Botswana, Lesotho, Namibia and Swaziland. The origins of the Agreement date back to 1889 making this one of the world’s oldest customs union agreements. The present version of the Act dates back to 1969. Since that time various conflicts have arisen between member countries regarding the objectives and operations of the agreement. Given the new political situation and the changing international trade climate, a decision has been made to renegotiate the agreement entirely. Discussions are now underway and these are being co-ordinated through the Customs Union Task Team which comprises representatives of the various countries. The South African government, through the Department of Trade and Industry recently held a workshop in order to brief interested parties. Parties have been invited to comment on the process and the Department has agreed to involve the Nedlac Trade and Industry chamber in any decision about the future of SACU.
- Full Text:
- Date Issued: 1995
Mulling over Art with Andrew Mulenga: UNZA, Hone students mitigate Zambia-China relations
- Authors: Mulenga, Andrew
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146837 , vital:38562 , https://www.themastonline.com/2019/10/01/mulling-overt-art-unza-hone-students-mitigate-zambia-china-relations/
- Description: China’s presence in Africa has been a contentious issue coupled with speculation that the Asian economic powerhouse is taking over the continent through some kind of neo-colonialism instigated by what some are calling the “Chinese Debt Trap”.
- Full Text:
- Date Issued: 2019
Descriptive Chemistry: PAC 121F
- Authors: Mrwebi, M , Hasheni, T , Tichagwa, L , Ajibade, A P
- Date: 2009-01
- Subjects: Chemistry
- Language: English
- Type: Examination paper
- Identifier: vital:17807 , http://hdl.handle.net/10353/d1010359
- Description: Descriptive Chemistry: PAC 121F, Examination January 2009.
- Full Text: false
- Date Issued: 2009-01
Interactive efficacies of Elephantorrhiza elephantina and Pentanisia prunelloides extracts and isolated compounds against gastrointestinal bacteria
- Authors: Mpofu, Smart J , Olivier, D K , Krause, Rui W M , Ndinteh, Derek T , Van Vuuren, S
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124122 , vital:35552 , https://doi.org/10.1016/j.sajb.2014.07.002
- Description: Elephantorrhiza elephantina (Burch.) Skeels (Fabaceae) and Pentanisia prunelloides (Klotzsch ex Eckl. & Zeyh.) Walp. (Rubiaceae) are two medicinal plants used extensively in southern Africa to treat various ailments. Often, decoctions and infusions from these two plants are used in combination specifically for stomach ailments. The antimicrobial activities of the methanol and aqueous extracts of the rhizomes of the two plants, as well as the two active ingredients from the plants [(−)-epicatechin and palmitic acid] have been determined apart and in combination against Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 8739) and Bacillus cereus (ATCC 11778). The minimum inhibitory concentration (MIC) values for the aqueous (0.50–16.00 mg/mL) and methanol (0.20–16.00 mg/mL) extracts independently demonstrated varied efficacies depending on the pathogen of study. When the two plants were combined in 1:1 ratios, synergistic to additive interactions (ΣFIC values 0.19–1.00) were noted. Efficacy for the two major compounds ranged between 0.13–0.63 mg/mL and mainly synergistic interactions were noted against E. faecalis and E. coli. The predominantly synergistic interactions noted between E. elephantina and P. prunelloides and major compounds, when tested in various ratios against these pathogens, provide some validation as to the traditional use of these two plants to treat bacterial gastrointestinal infections.
- Full Text:
- Date Issued: 2014
The effects of economic incentives in controlling pollution in the South African leather industry: die uitwerking van ekonomiese insentiewe op die beheer van besoedeling in die Suid-Afrikaanse leerbedryf
- Authors: Mowat, Shaun P , Antrobus, Geoffrey G , Fraser, Gavin C G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143057 , vital:38197 , DOI: 10.1080/03031853.1997.9523487
- Description: Pollution of the environment is becoming an increasingly serious problem. A large contributor to this is industry which generates effluent as a by-product of its production process. Two methods of controlling the pollution generated by industry are the so-called “command and control” techniques and economic incentives. In theory, economic incentives promise a more economically efficient and equitable means of pollution control. This paper sets out to ascertain whether this would hold in practice by applying environmental economic theory to the practical problem of controlling the effluent generated by one particular industry, viz the South African leather industry.
- Full Text:
- Date Issued: 2010
String diagrams for modelling functional programming
- Authors: Motara, Yusuf, M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429022 , vital:72554 , https://ieeexplore.ieee.org/abstract/document/9334072
- Description: It is currently impossible to model functional programs in the same way that UML is used to model object-oriented programs: no analogous graphical notation exists. Unlike object-oriented programs, however, functional programming is built on a solid mathematical basis and it may be possible to adapt graphical notation from the mathematical domain for such modelling. This work examines string diagrams as a way to model certain functional abstractions. A proposed notation is demonstrated in the contexts of equational reasoning and descriptive modelling, and is found to be suitable for both.
- Full Text:
- Date Issued: 2020
A quantitative post-release evaluation of biological control of water lettuce, Pistia stratiotes L. (Araceae) by the weevil Neohydronomus affinis Hustache (Coleoptera: Curculionidae) at Cape Recife Nature Reserve, Eastern Cape Province, South Africa
- Authors: Moore, Gareth R , Hill, Martin P
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:6839 , http://hdl.handle.net/10962/d1010987 , http://dx.doi.org/10.4001/003.020.0217 , https://orcid.org/0000-0003-0579-5298
- Description: [from the introduction] Water lettuce, Pistia stratiotes L. (Araceae) is recognized as being among the world’s worst aquatic weeds. In its adventive range, the plant forms extensive mats capable of blocking navigation channels, impeding water flow in irrigation and flood control canals, and disrupting hydropower generation (Holm et al. 1977). Dense mats of the weed prevent light penetration into the water column which negatively affects submerged aquatic plant communities, causing a lowering of the oxygen concentration and thereby reducing benthic invertebrate and fish populations (Neuenschwander et al. 2009).
- Full Text:
- Date Issued: 2012
Atypical HIV-vacuolar myelopathy: a case report :
- Authors: Mongezi, Tau , Sibi, Joseph , Jerry, George , Lourdes de Fátima, Ibañez Valdés , Tozama, Dubula , Humberto, Foyaca Sibat
- Date: 2021-06
- Subjects: South Africa HIV (Viruses) Cervical spondylotic myelopathy Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7670 , vital:54741 , https://doi.org/10.1186/s40001-021-00483-0
- Description: Background: Here, we report an atypical HIV-vacuolar myelopathy and search the available medical literature about atypical presentations of human immunodefciency virus associate vacuolar myelopathy (HIV-VM) and immunoglobu‑ lin therapy response. Case: A 26-year-old lady who was 4 weeks postpartum presented to us with acute faccid quadriparesis, with no sen‑ sory level. Extensive workup ruled out other causes of myelopathy. She developed a stage 3 acute kidney injury, and MRI showed difuse cord atrophy involving the lower cervical and thoracic cord. The patient received IV-immunoglob‑ ulin, ARVs, and supportive therapy with inadequate response. Unfortunately, she developed nosocomial pneumonia and died. Discussion: In HIV-VM, there is spinal cord atrophy, which mainly involves the thoracic cord. In our case, this patho‑ logical process also afected the spinal cord’s cervical region, leading to faccid tetraplegia, with high CD4 level, with‑ out response to the treatment, including intravenous immunoglobulin. Keynotes: Vacuolar myelopathy, HIV, Immunoglobulin therapy, faccid tetraplegia, hypokalaemia. Renal failure. Keywords: Human immunodefciency virus, Associated lesions of the nervous system, Human immunodefciency virus-associated myelopathy, Intravenous immunoglobulin administration, Case report, HIV-vacuolar myelopathy
- Full Text:
- Date Issued: 2021-06
Living with crime: Does crime affect victims' perceived quality of life?
- Authors: Moller, Valerie
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:21018 , http://hdl.handle.net/10962/6027 , http://dx.doi.org/10.17159/2413-3108/2004/v0i9a1032
- Description: Crime is thought to be a major concern that shapes the everyday lives of South Africans. But what impact does living with high levels of crime have on the mindset of ordinary citizens? A recent household crime victimisation study conducted in the Nelson Mandela Metropolitan Municipality provides tentative answers to this question.
- Full Text:
- Date Issued: 2004
Synthesis of molecularly imprinted polymer for selective solid-phase extraction of Salbutamol from urine samples
- Authors: Mohammadi, Ali , Alizadeh, Taher , Dinarvand, Rassoul , Ganjali, Mohammed M , Walker, Roderick B
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6410 , http://hdl.handle.net/10962/d1006496
- Description: A highly selective methacrylic based molecularly imprinted polymer (MIP) was synthesized and applied for the separation and the pre-concentration of salbutamol in urine samples. Spectrophotometric determination of salbutamol was achieved using 2,6-dichloroquinone chlorimide as colorimetric reagent. The detection limit of the method was ca. 13 ng/mL in urine after pre-concentration of the samples by MIP-SPE andanalysis with an optimized and sensitive spectrophotometric method. The linear dynamic range for salbutamol determination in urine was 0.04-0.75 μg mL-1. The recovery for the affinity based solid-phase extraction (SPE) with the MIP was more than 96 %.
- Full Text:
- Date Issued: 2009