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A case study on the health risks related to flood disasters in South Africa

- Tandlich, Roman, Ncube, Mbonisi, Khamanga, Sandile M, Zuma, Bongumusa M

Authors: Tandlich, Roman , Ncube, Mbonisi , Khamanga, Sandile M , Zuma, Bongumusa M
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/75917 , vital:30482 , DOI: 10.20965/jdr.2016.p0732
Description: Floods occurred in the Ndlambe Local Municipality in South Africa in October 2012. During various stages of the post-disaster recovery, bacterial concentrations were measured in water and soil samples from the flood zone. All drinking water concentrations of E. coli were below 1–3 colony forming units per 100 millilitres (CFUs/100 mL). The flood waters contained between 46500 to more than 100000 CFUs/100 mL of E. coli. {The concentrations of Salmonella spp. in the flood waters varied from 5000 to 250000 CFUs/100 mL. The presumptive Vibrio spp. concentrations in flood waters ranged from 1000 to over 150000 CFUs/100 mL. {The soil concentrations for E. coli ranged from 1 to above 330 colony-forming units per 1 g of soil dry weight (CFUs/g). The soil concentrations of Salmonella spp. varied from below 1 to 22 CFUs/g. The estimated airborne fungal concentrations ranged from 16820 to 28540 colony-forming units per 1 cubic meter. An outbreak of an infectious disease was recorded among the volunteers who assisted with the post-disaster recovery. The likely bacterial causative agents included strains of Aeromonas spp. and Vibrio cholerae. Any human contact with either the contaminated flood waters or of flooded dwellings should only occur, if the individuals in questions are equipped with the full-body personal protective gear. Non-governmental stakeholders performed majority of the post-disaster recovery operations, as the local government could only cover 11% of the required costs. Applying sanitation funds to disaster recovery and increased use of the low-cost flood defence products in high risk areas could provide a solution for the future.
Full Text: false
Date Issued: 2016

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A cytotoxic pentadecapeptide from a South African Didemnid tunicate

- Gallegos, D, Serrill, J, Parker-Nance, Shirley, Dorrington, Rosemary A, Ishmael, J, McPhail, Kerry L

Authors: Gallegos, D , Serrill, J , Parker-Nance, Shirley , Dorrington, Rosemary A , Ishmael, J , McPhail, Kerry L
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/65935 , vital:28863 , https://doi.org/10.1055/s-0036-1596683
Description: publisher version , The rate of discovery of new natural product chemical entities has plateaued, and unique populations of endemic, biologically diverse sessile marine organisms represent increasingly critical opportunities to discover new chemistry. Discovery of the mandelalides [1] as potent inhibitors of cancer cell growth from the new South African tunicate Lissoclinum mandelai is an example of the diverse suites of metabolites with potent biological activities that have been isolated from tunicates and other filter-feeding sessile marine organisms that house complex microbial consortia. Further investigation of archived and new tunicate collections from Algoa Bay, South Africa, has revealed a group of didemnid tunicates with an unusual gelatinous morphology similar to Lissoclinum mandelai. Using a bioassay-guided isolation approach, a new “gelatinous” species of the genus Didemnum has yielded a cytotoxic pentadecapeptide with a molecular mass of 1603.7688 Da, comprising fifteen residues including both proteinogenic and non-proteinogenic amino acids. The pure compound inhibited both HeLa cervical cancer and NCI-H460 non-small cell lung cancer cell lines when tested at 30 nM in preliminary assays against cells seeded at low densities. Inhibition of cancer cells at low starting density may be indicative of an anti-proliferative mechanism of action. The compound did not show antibacterial activity against Vibrio cholera. Didemnin B and its clinically approved analogue dehydrodidemnin B (plitidepsin, Aplidin®) [2, 3] are important macrocyclic depsipeptides from a didemnid tunicate. The pentadecapeptide reported here provides justification for our continued investigation of unique, endemic didemnid tunicates from South Africa as a source of new macrocyclic natural products with cytotoxic, anti-viral or antimicrobial activity. , We acknowledge the South African government for permission to collect the subject tunicate (Collection Permit No. 278 RES2013/43)
Full Text: false
Date Issued: 2016

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A feminist perspective on autonomism and commoning, with reference to Zimbabwe

- Alexander, Tarryn, Helliker, Kirk D

Authors: Alexander, Tarryn , Helliker, Kirk D
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/71374 , vital:29838 , https://doi.org/10.1080/02589001.2016.1235353
Description: This article engages with the autonomist Marxism of John Holloway from a feminist standpoint. The positions developed by this feminist critique are used to shed new light on the land occupations in contemporary Zimbabwe. Though sympathetic to his work, we argue that Holloway does not sufficiently address gender identity with specific reference to social reproduction and women. The notions of the commons and the process of commoning are consistent with Holloway’s autonomist framework and its complementarities to Silvia Federici’s Marxist feminist lens on the commons is highlighted. Against a tendency within autonomist and commoning theories, we argue for a pronounced identitarian politics as grounded in localised struggles undertaken by women as women. We privilege the significance of women asserting and revaluing their identities as part of a possible project of transformation. For us, struggling against and beyond what exists is invariably rooted in struggles within what exists (including identities).
Full Text: false
Date Issued: 2016

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A passive auxiliary circuit with interphase transformer applied in 12-pulse converters to provide clean power utility interface

- Shih, Der-Chun, Young, Chung-Ming, Whiteley, Chris G

Authors: Shih, Der-Chun , Young, Chung-Ming , Whiteley, Chris G
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/67095 , vital:29031 , https://doi.org/10.1080/02533839.2016.1230029
Description: publisher version , This paper proposes a passive auxiliary circuit which can be added to an interphase transformer (PAC + IPT) configuration to reduce the total harmonic distortion (THD) existing in 12-pulse diode rectifier converter systems at AC mains. The proposed PAC + IPT compensation method is a simple structure, with low power consumption and requires no extra DC power supply. We present the theoretical analysis of the proposed topology that lessens the total harmonic distortion (THD) and evaluate the dynamic simulation results on a 12-pulse converter system and a 3-kW laboratory prototype. Both the simulation and the experimental results show that the proposed PAC + IPT compensation method can improve the power quality and provide a clean power utility interface of AC line input currents for a conventional 12-pulse diode rectifier converter.
Full Text: false
Date Issued: 2016

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Administrative penalties

- Arendse, Jacqueline A, Clegg, David, Williams, Robert C

Authors: Arendse, Jacqueline A , Clegg, David , Williams, Robert C
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , book chapter
Identifier: http://hdl.handle.net/10962/131225 , vital:36539 , https://store.lexisnexis.co.za/products/silke-on-tax-administration-skuZASKUPG1440
Description: Provisions dealing with the levying of interest and penalties are contained in the Tax Administration Act and specific provisions also exist in the various tax Acts. Most of the specific penalty provisions in the various tax Acts have been replaced by the general provisions contained in the Tax Administration Act.
Full Text: false
Date Issued: 2016

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Advance rulings

- Arendse, Jacqueline A, Clegg, David, Williams, Robert C

Authors: Arendse, Jacqueline A , Clegg, David , Williams, Robert C
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , book chapter
Identifier: http://hdl.handle.net/10962/131195 , vital:36535 , https://store.lexisnexis.co.za/products/silke-on-tax-administration-skuZASKUPG1440
Description: Chapter 7 of the Tax Administration Act, namely ss 75–90, deals with the formal system and process of the advance tax ruling system. It therefore follows that SARS may now issue advance rulings in respect of all tax types and tax Acts administered by the Commissioner. Procedures and guidelines, in the form of ‘binding general rulings’, for implementation and operation of the ‘advance ruling’ system may be issued by the Commissioner to give effect to the advance tax ruling system.
Full Text: false
Date Issued: 2016

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An analysis of how students construct knowledge in a course with a hierarchical knowledge structure

- Myers, Peta L

Authors: Myers, Peta L
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/66995 , vital:29014 , https://doi.org/10.1080/10291954.2016.1196528
Description: publisher version , Passing the introductory accounting semester is often seen as a challenge for first year students. Being aware of both effective and ineffective ways of constructing knowledge in a discipline with a hierarchical knowledge structure will be of value to students and teachers alike in assisting in the development of effective styles of learning. This article, which is part of a larger body of research, analyses how students in an introductory financial accounting class at Rhodes University constructed knowledge. Previous research described the course as having a hierarchical knowledge structure. In this research, first year accounting students at Rhodes University were interviewed to gain an improved understanding of how they constructed knowledge in this course. This article describes how students who were successful in passing this semester course used similar, effective ways of constructing knowledge, while students who were not successful also employed similar but less effective ways of constructing knowledge. These different ways of constructing knowledge, both effective and ineffective, were analysed, using the Bernstein’s pedagogic device and Maton’s Legitimation Code Theory. This article provides those involved in teaching and learning in a discipline with a hierarchical knowledge structure, with a theoretical explanation of why some methods of constructing knowledge are more effective than others. Understanding and being explicit about more (and less) effective ways of constructing knowledge in a course with a hierarchical knowledge structure can guide those involved in teaching and learning to improve results.
Full Text: false
Date Issued: 2016

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Audit, investigation, search, seizure and access to information

- Arendse, Jacqueline A, Clegg, David, Williams, Robert C

Authors: Arendse, Jacqueline A , Clegg, David , Williams, Robert C
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , book chapter
Identifier: http://hdl.handle.net/10962/131245 , vital:36541 , https://store.lexisnexis.co.za/products/silke-on-tax-administration-skuZASKUPG1440
Description: Chapter 5 of the Tax Administration Act, which supplements the various fiscal statutes, empowers SARS to call for information on taxpayers, conduct audits, investigations and in certain instances to search premises and seize goods and records. For this purpose, taxpayers are required to keep proper books and records (see § 8.2 and § 4). The purpose of a tax audit is to verify the accuracy and timing of an assessment, but more specifically to ensure accuracy and full disclosure in terms of the law. In the event that an audit reveals non-compliance, criminal and/or civil charges may be initiated by SARS (see § 8.5).
Full Text: false
Date Issued: 2016

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Binding and entry of a non-enveloped T=4 insect RNA virus is triggered by alkaline pH

- Penkler, David L, Jiwaji, Meesbah, Domitrovic, Tatiana, Short, James R, Johnson, John E, Dorrington, Rosemary A

Authors: Penkler, David L , Jiwaji, Meesbah , Domitrovic, Tatiana , Short, James R , Johnson, John E , Dorrington, Rosemary A
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/65995 , vital:28875 , https://doi.org/10.1016/j.virol.2016.08.028
Description: publisher version , Tetraviruses are small, non-enveloped, RNA viruses that exclusively infect lepidopteran insects. Their particles comprise 240 copies of a single capsid protein precursor (CP), which undergoes autoproteolytic cleavage during maturation. The molecular mechanisms of capsid assembly and maturation are well understood, but little is known about the viral infectious lifecycle due to a lack of tissue culture cell lines that are susceptible to tetravirus infection. We show here that binding and entry of the alphatetravirus, Helicoverpa armigera stunt virus (HaSV), is triggered by alkaline pH. At pH 9.0, wild-type HaSV virus particles undergo conformational changes that induce membrane-lytic activity and binding to Spodoptera frugiperda Sf9 cells. Binding is followed by entry and infection, with virus replication complexes detected by immunofluorescence microscopy within 2 h post-infection and the CP after 12 h. HaSV particles produced in S. frugiperda Sf9 cells are infectious. Helicoverpa armigera larval virus biofeed assays showed that pre-treatment with the V-ATPase inhibitor, Bafilomycin A1, resulted in a 50% decrease in larval mortality and stunting, while incubation of virus particles at pH 9.0 prior to infection restored infectivity. Together, these data show that HaSV, and likely other tetraviruses, requires the alkaline environment of the lepidopteran larval midgut for binding and entry into host cells.
Full Text: false
Date Issued: 2016

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Biological activity of extracellular and intracellular polysaccharides from Pleurotus tuber-regium hybrid and mutant strains

- Bamigboye, Comfort O, Oloke, Julius K, Dames, Joanna Felicity

Authors: Bamigboye, Comfort O , Oloke, Julius K , Dames, Joanna Felicity
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/69056 , vital:29376 , http://pubs.sciepub.com/jfnr/4/7/2/
Description: Publisher version , Pleurotus tuber-regium (Fr.) Singer (1951) is a unique sclerotium-forming edible and medicinal mushroom. Interestingly, both the sclerotium and mushroom are edible and are often used for curing various ailments. Previous studies have focused on the antimicrobial and antioxidant activity of the extracellular polysaccharide (EPS) from wild P. tuber-regium. There has been no report on the intracellular polysaccharide (IPS) of the wild mycelia, likewise there is very meager information on the improvement of the perceived potentials of P. tuber-regium. This research study analysed the EPS and IPS fractions of P. tuber-regium hybrid and mutant strains. The antimicrobial potential of the IPS and EPS fractions, their scavenging activity on 1, 1-diphenyl–2picryhydrazyl (DPPH) and Hydroxyl radicals were also determined. Both IPS and EPS fractions of P. tuber-regium hybrids and mutants showed increased DPPH and hydroxyl scavenging activity over the wild P. tuber-regium with an EC50 mostly 1 mg/ml. The antimicrobial activity of the IPS from a mutant strain had an IC50 of 15.6 mg/ml compared to the wild type (18.75 mg /ml). This study showed that selected mutant and hybrids of P. tuber-regium had increased radical scavenging activity indicating potentially increased biological activity that could offer increased benefit as a neutraceutical.
Full Text: false
Date Issued: 2016

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Changing practices, changing values?: a Bernsteinian analysis of knowledge production and knowledge exchange in two UK universities

- Little, Brenda, Abbas, Andrea, Singh, Mala

Authors: Little, Brenda , Abbas, Andrea , Singh, Mala
Date: 2016
Language: English
Type: text , book
Identifier: http://hdl.handle.net/10962/66934 , vital:29002 , https://doi.org/10.1007/978-94-017-7369-0_8
Description: publisher version , Bernstein’s concept of classification and framing links notions of knowledge, democracy and social justice, providing a perspective from which to address critical questions of what knowledge is produced, who has access to it, and how knowledge is distributed. Bernstein’s conceptual framework is used to inform an analysis of national policies steering knowledge production and knowledge transfer in the UK, and the changing practices and values associated with knowledge production and knowledge transfer in two UK institutional case study universities. The analysis reveals how reputational and financial consequences of the formal assessment of research quality interacts with the institutional and disciplinary contexts of research units to differently shape what knowledge is valued and produced, and with whom it is shared. Five discursive areas, each involving a complex set of classifications (power) and framings (control) are identified, namely: the national research assessment framework; the economic value of research; discourses of social and academic values; academic freedoms; and mixed-discipline research and the interdisciplinary nature of real world problems. Though competing and sometimes contradictory values seem to underlie academics’ knowledge work, it seems that the strong framing for knowledge production and knowledge exchange provided by national policies steers staff efforts towards economised codes of knowledge. The conclusion suggests that such a strong steer does not value social transformation in all its diverse non-economistic dimensions and limits universities’ potential to transform societies to further social justice.
Full Text: false
Date Issued: 2016

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Co-management, land rights, and conflicts around South Africa’s Silaka Nature Reserve

- Thondhlana, Gladman, Cundill, Georgina, Kepe, Thembele

Authors: Thondhlana, Gladman , Cundill, Georgina , Kepe, Thembele
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/67781 , vital:29144 , https://doi.org/10.1080/08941920.2015.1089609
Description: Publisher version , Globally, co-management of protected areas (PAs) offers promise in efforts to achieve ecological integrity and livelihood needs. Most co-management agreements are premised on joint decision making in defining equitable sharing of benefits from and the management responsibilities for natural resource management. However, co-managed PAs are often conflict ridden. The forceful closure of Silaka Nature Reserve in South Africa in 2013 by a local community epitomizes the conflicts that can emerge in co-management arrangements. Using Silaka Reserve as a case study, we ask questions related to the meaning of land to local people, with an interrogative focus beyond “material benefits” in co-management discourse. The results of this study show that apart from nonaccrual of material benefits, conflicts arise from nonrecognition of nonmaterial aspects such as cultural values of and historical attachment to land and limited involvement of land claimants in decision making. The implications for co-management as a desired outcome on settled land claims are discussed.
Full Text: false
Date Issued: 2016

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Computer simulations of the interaction of human immunodeficiency virus (HIV) aspartic protease with spherical gold nanoparticles: implications in acquired immunodeficiency syndrome (AIDS)

- Whiteley, Chris G, Lee, Duu-Jong

Authors: Whiteley, Chris G , Lee, Duu-Jong
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/67083 , vital:29030 , https://doi.org/10.1088/0957-4484/27/36/365101
Description: publisher version , The interaction of gold nanoparticles (AuNP) with human immune-deficiency virus aspartic protease (HIVPR) is modelled using a regime of molecular dynamics simulations. The simulations of the 'docking', first as a rigid-body complex, and eventually through flexible-fit analysis, creates 36 different complexes from four initial orientations of the nanoparticle strategically positioned around the surface of the enzyme. The structural deviations of the enzymes from the initial x-ray crystal structure during each docking simulation are assessed by comparative analysis of secondary structural elements, root mean square deviations, B-factors, interactive bonding energies, dihedral angles, radius of gyration (R g), circular dichroism (CD), volume occupied by C α , electrostatic potentials, solvation energies and hydrophobicities. Normalisation of the data narrows the selection from the initial 36 to one 'final' probable structure. It is concluded that, after computer simulations on each of the 36 initial complexes incorporating the 12 different biophysical techniques, the top five complexes are the same no matter which technique is explored. The significance of the present work is an expansion of an earlier study on the molecular dynamic simulation for the interaction of HIVPR with silver nanoparticles. This work is supported by experimental evidence since the initial 'orientation' of the AgNP with the enzyme is the same as the 'final' AuNP-HIVPR complex generated in the present study. The findings will provide insight into the forces of the binding of the HIVPR to AuNP. It is anticipated that the protocol developed in this study will act as a standard process for the interaction of any nanoparticle with any biomedical target.
Full Text: false
Date Issued: 2016

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Developmental and spatial variations in the diet signatures of hyperbenthic shrimp Nauticaris marionis at the Prince Edward Islands based on stable isotope ratios and fatty acid profiles

- Richoux, Nicole B, Allan, Elizabeth L, Froneman, P William

Authors: Richoux, Nicole B , Allan, Elizabeth L , Froneman, P William
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/67923 , vital:29169 , https://doi.org/10.1016/j.csr.2016.02.0131
Description: Publisher version , The caridean shrimp Nauticaris marionis is an ecologically important species in the benthic community around the sub-Antarctic Prince Edward Islands (PEI) as it represents a key prey item for a variety of top predators breeding on the islands. We hypothesized that the diet of N. marionis shifts during its development, and that spatial variability in food availability results in differentiation in the diet signatures of specimens collected from various locations of the shelf waters around the PEI. Specimens were collected from nine stations (depth range 70 to 240 m) around the PEI at inter-island shelf (from west to east: upstream, between and downstream) and nearshore regions during austral autumn 2009. Stable isotope and fatty acid data both revealed spatial and developmental variations in the shrimp diet. Nearshore shrimp were more 13C-enriched than those from the inter-island region, suggesting increased kelp detritus entered the food web in the nearshore regions. The shrimp showed increases in δ13C and δ15N signatures (and trophic position) with an increase in body size, resulting in distinctions between size classes that reflected shifts in their trophic niche through development. The fatty acid profiles similarly indicated distinctions in diet with increased shrimp size (in the deep regions), and spatial variability was evident in relation to region and depth. All shrimp contained large proportions of polyunsaturated and essential fatty acids, indicating that the quality of food consumed was similar between regions despite the diet variability. Our results provide new dietary information about a key species operating near the base of the food web at the highly productive PEI, and show that there were no areas of enhanced nutrition available to the shrimp. As such, there was no nutritional advantage to shrimp inhabiting any specific region around the PEI.
Full Text: false
Date Issued: 2016

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Diet of the endemic bivalve Solen cylindraceus inferred from stable isotope analysis in the Kariega Estuary, South Africa

- Nel, Holly A, Froneman, P William

Authors: Nel, Holly A , Froneman, P William
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/67933 , vital:29170 , https://doi.org/10.1080/13235818.2016.1175917
Description: Publisher version , Sedentary filter-feeders such as the razor clam (Solen cylindraceus) are believed to indiscriminately exploit a carbon source derived from particulate organic matter (POM). POM demonstrates a high degree of spatial and temporal variability in composition, which may result in intraspecific dietary variation. This study aimed to investigate seasonal ontogenetic shifts in the feeding ecology of S. cylindraceus using dual stable isotopic (δ13C and δ15N) analyses in the oligotrophic temperate permanently open Kariega Estuary, South Africa. Mixing model results demonstrate that the different size classes of S. cylindraceus had a diet comprised mainly of POM. However, size grouping did have a significant effect on carbon and nitrogen signatures. Specifically, during winter, carbon isotopic signatures became more depleted with a decrease in size, while both winter and summer δ15N values became more nitrogen enriched with an increase in size. The observed trend in the ratios can likely be ascribed to the hydrodynamics of the system. Data from this study suggest that there may be some degree of variation among the different size cohorts, although this needs further investigation.
Full Text: false
Date Issued: 2016

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Disaster management policy options to address the sanitation challenges in South Africa

- Hoossein, Shafick, Tandlich, Roman, Whittington-Jones, Kevin J, Laubscher, Richard K, Madikizela, Phindile, Zuma, Bongumusa M

Authors: Hoossein, Shafick , Tandlich, Roman , Whittington-Jones, Kevin J , Laubscher, Richard K , Madikizela, Phindile , Zuma, Bongumusa M
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/75938 , vital:30485 , https://www.neha.org/node/28591
Description: The current population of South Africa has been migrating into informal urban settlements that lack adequate sanitation service delivery, caused at least in part by the lack of the necessary skills in the local government sector and the lack of buy in from the community into the provided sanitation facilities. The authors report results of policy research into the relevant disaster management options that could be applied to improve the sanitation service delivery in South Africa. The best policy option was identified as the draft Disaster Management Regulations: Disaster Management. Local government can use these tools through the formation of the volunteer units from the nongovernmental organization sector, the business community, and from among the end users of sanitation facilities. Formation of the volunteer unit should follow the principles of cooperative governance and participatory approach to disaster management. Implementation should be facilitated through the adoption of locally specific municipal by laws.
Full Text: false
Date Issued: 2016

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Dispute resolution

- Arendse, Jacqueline A, Clegg, David, Williams, Robert C

Authors: Arendse, Jacqueline A , Clegg, David , Williams, Robert C
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , book chapter
Identifier: http://hdl.handle.net/10962/131084 , vital:36522 , https://store.lexisnexis.co.za/products/silke-on-tax-administration-skuZASKUPG1440
Description: Chapter 9 of the Tax Administration Act 2011, deals with the objection and appeals processes of the tax Acts administered by SARS in terms of s 4 of the SARS Act, 1997. A taxpayer who is aggrieved by an assessment or a decision in which he has an interest, has the right to object against the assessment or decision.
Full Text: false
Date Issued: 2016

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Distribution and ecological assessment of heavy metals in irrigation channel sediments in a typical rural area of south China

- Gu, Chiming, Liu, Yi, Li, Zhiguo, Mohamed, Ibrahim, Zhang, Ronghua, Brooks, Margot, Chen, Fang

Authors: Gu, Chiming , Liu, Yi , Li, Zhiguo , Mohamed, Ibrahim , Zhang, Ronghua , Brooks, Margot , Chen, Fang
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/66924 , vital:29000 , ISSN 0925-8574 , https://doi.org/10.1016/j.ecoleng.2016.01.054
Description: Publisher version , Elevated levels of heavy metals in sediments of irrigation channels can pose risks for crops and livestock, as well as for human health. In this study sediment samples were collected from the irrigation channel in a typical rural area of south China, and digested, in order to analyze their contents for the presence of heavy metals Cu, Zn, Pb, Cr, Cd, and Ni, as well as the non-metal As, to assess total concentrations and pollution levels. The pollution load index and potential ecological risk index of these elements were utilized to assess contamination levels and ecotoxicity. Our results showed that the concentrations of the 7 elements were in the order of Zn > Ni > Cr > Cu > As > Pb > Cd. With the exception of Cr and Pb, concentrations of elements were higher than their background in soil, especially for Cd (1.79 mg kg−1), As (99.61 mg kg−1) and Ni (142.62 mg kg−1), which were 18.49, 8.89 and 5.30 times their background concentrations, respectively. The whole sampled zone was characterized by medium pollution and had a very high potential ecological risk. The area of arable land presented a medium pollution risk, while areas near to the path or road showed high risk of pollution. The predominant contributors to elevated ecological risk for the whole zone were Cd and As.
Full Text: false
Date Issued: 2016

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Distribution of benthic diatom communities in a permanently open temperate estuary in relation to physico-chemical variables

- Dalu, Tatenda, Richoux, Nicole B, Froneman, P William

Authors: Dalu, Tatenda , Richoux, Nicole B , Froneman, P William
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/67943 , vital:29172 , https://doi.org/10.1016/j.sajb.2015.06.004
Description: Publisher version , The spatial and temporal patterns in benthic diatom community structure in temperate permanently open estuaries are poorly understood. In this study, we used a combination of multivariate and diversity indices to elucidate environmental factors associated with diatom community structure in the Kowie Estuary, South Africa. Benthic diatom samples were collected from three sites corresponding to the upper, middle and lower reaches of the estuary on four occasions over the period early spring 2012 to winter 2013. Among the 89 benthic diatoms observed, Entomoneis paludosa (W Smith) Reimer, Nitzschia reversa W Smith, Nitzschia closterium (Ehrenberg) W Smith, Pleurosigma elongatum W Smith, P. salinarum (Grunow) Grunow, Staurosira elliptica (Schumann) DM Williams & Round, Surirella brebissonii Krammer & Lange-Bertalot, and Surirella ovalis Brébisson were the numerically dominant species. Principal component analysis demonstrated that the diatom community structure was determined by a variety of factors including nutrient (ammonia, nitrate) concentrations, hydrology (e.g., water depth and flow) and pH. Hierarchical cluster analysis revealed the absence of any distinct spatial patterns, although distinct benthic diatom communities were recorded during the different sampling periods. The species richness was highest in the middle reach, decreasing from early spring to summer in all reaches. The results of the study provide important insights into the various factors that structure benthic diatom community composition within a permanently open temperate southern African estuary.
Full Text: false
Date Issued: 2016

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