Development and validation of DNA barcoding for biodiversity assessment and conservation of red algae in the Algoa Bay region
- Authors: Mshiywa, Faith Masilive
- Date: 2017
- Subjects: Red algae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9011 , vital:34182
- Description: DNA barcoding is a molecular technique that uses a short DNA sequence for species identification. It harnesses global community efforts to establish large-scale public reference libraries to allow species identification. Red algae are a complex group of species and are difficult to identify on morphological grounds only. Red algae have the highest production of halogenated compounds, and are used in the medical and pharmaceutical industries. This study therefore aimed at developing DNA barcodes, universal primers and a Kenton-on-Sea red algae species list, which will aid as a baseline for red algae biodiversity and conservation research. A potential DNA barcode region was designed from the rbcL gene, because rbcL is easy to amplify, easy to sequence and it can differentiate organisms to species level. Primers were designed from multiple red algae rbcL sequences and they were evaluated using bioinformatics tools. Red algae from the Algoa Bay region were screened with these primers and a 77% PCR amplification success was obtained. The PCR products were sequenced and 96% of the amplicons were successfully sequenced and resulted in a barcode sequence length above 700bp, which could be used to identify red algae species. Twenty-six (26) red algae species from Kenton-on-Sea, near Algoa Bay, were successfully identified using the Barcode sequence amplified from a primer set developed from the rbcL gene and were uploaded on the BOLD database for public access. This barcode is, therefore, suitable for use by the South African National Biodiversity Institute or other marine researchers, to identify South African red algae species and ensure the maintenance of their biodiversity and conservation.
- Full Text:
- Date Issued: 2017
Development of a liposomal acyclovir mucoadhesive film
- Authors: Nalungwe, Sarah
- Date: 2017
- Subjects: Clinical pharmacology , Liposomes Nanomedicine
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/14212 , vital:27451
- Description: Acyclovir is a synthetic purine nucleoside analogue with in vitro and in vivo inhibitory activity against herpes simplex virus types 1 (HSV-1), 2 (HSV-2), and varicella-zoster virus (VZV). The efficacy of oral acyclovir is limited as a result of its low bioavailability (15-30%) as it is poorly water soluble and therefore requires a frequent dosing regimen. When orally administered, peak plasma concentration occurs after 1.5–2.5 hours, while its elimination half-life is approximately 2-3 hours. Acyclovir displays poor solubility in water and in lipid bilayers, which leads to poor drug levels at target sites after oral, local, or parenteral administration. In order to improve this lack of solubility, novel amphiphilic derivatives have been designed to form nanoparticles, which allow for the efficient encapsulation of this hydrophobic antiviral agent. Reformulation of drugs in liposomes has provided an opportunity to enhance the therapeutic indices of various agents mainly via alteration of their bio-distribution. Liposomal drug delivery systems have received considerable attention due to their immense advantages which include, effective encapsulation of both small and large molecules that have a wide range of hydrophobicity levels and pKa values, prolonging and targeting release of therapeutic agents by modification of liposomal surface and also minimising clinical drug dose thus reducing toxicity effects. Liposomes exhibit a number of special biological characteristics, including specific interactions with biological membranes and various cells, hence, liposomes are used as biocompatible carriers to improve delivery properties across mucus membranes. Mucoadhesive dosage forms may be designed to enable prolonged retention at the site of application, providing a controlled rate of drug release for improved therapeutic outcome. The aim of this study was to develop an acyclovir liposomal mucoadhesive film by actively encapsulating acyclovir into liposomes and preparing a mucoadhesive film to optimise delivery of acyclovir liposomes at target sites. To actively encapsulate acyclovir and prepare the acyclovir-containing liposomes, a comprehensive statistical methodology was used in optimising the liposome formulation to encapsulate acyclovir. Central composite design was used as the response surface methodology statistical tool to design and develop an optimised method for active encapsulation of acyclovir into liposomes. The predicted optimised encapsulation parameters were incubation temperature of 60 °C and incubation time of 45 minutes. The mean percentage encapsulation calculated was 27.72%. The overall average size of the liposomes was 99.5 nm with a narrow distribution polydispersity index of 0.105 and were physically characterised as small unilamellar vesicles which possessed an average zeta potential of -45.6 mV. High Performance Liquid Chromatography (HPLC) was used to analyse and determine acyclovir drug content in the liposomes and drug release pattern from the mucoadhesive film. Polyvinyl-pyrrolidone (PVP) and Polyethylene glycol (PEG) were used in the preparation of mucoadhesive film, in which the acyclovir encapsulated liposomes were incorporated. The average amount of acyclovir drug content quantified to be in 4 cm2 of the mucoadhesive film was 36.8543 μg. The average tensile strength of the mucoadhesive film was determined to be 3.06 N/mm2 with an elongation percentage of 4.54%. The toughness of the film was 71.50 N.mm and the force required to rupture film was 16.49 N. The work and maximum force required to detach the mucoadhesive film from the glass side was 2.58 N.mm and 11615.32 mN, respectively. A Franz diffusion cell was used to perform acyclovir drug release studies from the mucoadhesive film and a commercial brand of acyclovir cream (Acitop®). Percentage acyclovir drug release from the film and cream was plotted against time using Sigmaplot® software version 13 following First order, Peppas, Hixon and Crowell, Higuchi (Square Root Time) and Bakers and Lonsdale mathematical models. The mucoadhesive film acyclovir attained the highest correlation coefficient r2 of 0.9879 following the Baker & Lonsdale mathematical model which describes controlled drug release from spherical matrices hence fits the model as the acyclovir is encapsulated in liposomes which are incorporated in the polymer mucoadhesive film. And the acyclovir cream (Acitop®) attained the highest correlation coefficient r2 of 0.9944 following the Peppas mathematical model. The Peppas model has been used to describe drug release from various release dosage forms when there is more than one type of dosage release or when release mechanism is not well known. One assumption of this model is that drug release occurs in one dimension, which is a suitable release profile for the cream as it is absorbed through the skin in one dimension when applied topically. There was significant difference between the drug release data for the mucoadhesive film and the acyclovir cream (Acitop®). A physically stable mucoadhesive film containing acyclovir-loaded liposomes was developed.
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- Date Issued: 2017
Development of a MPEG-7 based multimedia content description and retrieval tool for internet protocol television (IPTV)
- Authors: Ncube, Prince Daughing Ngqabutho
- Date: 2017
- Subjects: MPEG (Video coding standard) Digital television Multimedia communications
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4893 , vital:28738
- Description: Search and retrieval of multimedia content from open platforms such as the Internet and IPTV platforms has long been found to be hugely inefficient. It has been noted that a major cause of such inefficient results is the improper labeling or incomplete description of multimedia content by its creators. The lack of adequate description of video content by the proper annotation of video content with the relevant metadata leads to poor search and retrieval yields. The creation of such metadata itself is a major problem as there are various metadata description standards which users could employ. On the other hand there are tools such as FFprobe that can retrieve important features of video that can be used in searching and retrieval. The combination of such tools and metadata description standards could be the solution to the metadata problem. The Multimedia Content Description Interface (MPEG-7) is an example of a metadata description standard. It has been adopted by TISPAN for the description of IPTV multimedia content. The MPEG-7 standard is rather complex, seeing as it has over 1200 global Descriptors and Description Schemes which a user would have to know in order to implement such technology. This complexity is a nuisance when we consider the existence of multitudes of amateur video producers. These multimedia content creators have no idea how to use the MPEG-7 standard to annotate their creations with metadata. Consequently, overloading of the IPTV platform with content that has not been annotated in a standardized manner occurs, making search and retrieval of the multimedia content (videos, in this instance) inefficient. Therefore, it was imperative to try and determine whether the use of the MPEG-7 standard could be made much easier by creating a tool that is MPEG-7 enabled which will allow for the annotation of video content by any user without concerning themselves about how to use the MPEG-7 standard. In attempting to develop a tool for metadata generation, it was incumbent for us to understand the issues associated with metadata generation for users wishing to create IPTV services. An extensive literature review on IPTV standardization was carried out to determine the issues associated with metadata generation for IPTV and their proposed solutions. An experimental research approach was taken in an attempt to figure out if our proposed solution to the lack of technical expertise by users about the MPEG-7 standard could be the final solution to the metadata generation problem. We developed a Multimedia Content Description and Management System (MCDMS) prototype which enabled us to describe video content by annotating it with 16 different metadata elements and storing the descriptions in XML MPEG-7 format. Incremental development and re-use oriented development were used during the development phase of this research. The MCDMS underwent functional testing; smoke testing of the individual system components and Big Bang integration testing for the combined components. Our results indicate that the more metadata is appended to a video as description the better it is to search for and retrieve. The MCDMS hides the complexity of MPEG-7 metadata creation from the users. With the effortless creation of MPEG-7 based metadata, it becomes easier to annotate videos. Consequently, search and retrieval of video content becomes more efficient. It is important to note that the description of multimedia content remains a complex feat. Even with the metadata elements laid out for users, there still exist other issues that affect metadata creation such as polysemy and the semantic gap. However, the provision of a tool that does the MPEG-7 standardizing behind the scenes for users when they upload a video makes the description of multimedia content in a standardized manner a much easier feat to achieve.
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- Date Issued: 2017
Development of an automatic news summarizer for isiXhosa language
- Authors: Ndyalivana, Zukile
- Date: 2017
- Subjects: Text processing (Computer science) Automatic abstracting Computational linguistics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/7875 , vital:30783
- Description: From practice perspective, given the abundance of digital content nowadays, coming up with a technological solution that summarizes written text without losing its message, coherence and cohesion of ideas is highly essential. The technology saves time for readers as well as gives them a chance to focus on the contents that matter most. This is one of the research areas in natural language processing/ information retrieval, which the dissertation tries to contribute to. It tries to contextualize tools and technologies that are developed for other languages to automatically summarize textual Xhosa news articles. Specifically, the dissertation aims at developing a text summarizer for textual Xhosa news articles based on the extraction methods. In doing so, it examines the literature and understand the techniques and technologies used to analyse contents of a written text, transform and synthesize it, the phonology and morphology of the Xhosa language, and finally, designs, implements and test an extraction-based automatic news article for the Xhosa language. Given comprehension and relevance of the literature review, the research design, the methods and tools and technologies used to design, implement and test the pilot system. Two approaches were used to extract relevant sentences, which are, term frequency and sentence position. The Xhosa summarizer is evaluated using a test set. This study has employed both subjective and objective evaluation methods. The results of both methods are satisfactory. Keywords: Xhosa, Automatic Text Summarization, Term Frequency and Sentence Position.
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- Date Issued: 2017
Development of antibiotic loaded liposomal hydrocolloid dressings for application in wound healing
- Authors: Ntsalu, Vuyiseka
- Date: 2017
- Subjects: Wound healing -- South Africa Liposomes Hydrocolloid surgical dressings -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/13957 , vital:27361
- Description: Wound healing, as a normal biological process in the human body, is achieved through four precise and highly programmed phases: hemostasis, inflammation, proliferation, and remodeling. For a wound to heal successfully, all four phases must occur in the proper sequence and time frame. However, many factors can interfere with one or more of these phases, thus causing improper or impaired wound healing. Maintaining a moist wound environment is crucial in facilitating the wound-healing process. The beneficial effects of a moist versus a dry wound environment include re-epithelization, tissue granulation, and repair. The use of hydrocolloid occlusive dressings in maintaining a moist wound environment has proven to be a useful adjunct in facilitating wound healing. Although hydrocolloid dressings have been widely used clinically in wound management, bacterial resistance, poor solubility and sustained drug release remain to be a problem for many of the drugs used in wound therapy. In chronic wound management, where patients normally undergo long treatments and frequent dressing changes, a system that delivers drugs into a wound site in a controlled fashion can improve patient compliance and therapeutic outcomes. Liposomes are small phospholipid vesicles that have been widely investigated as drug carriers for the delivery of therapeutic agents. They are spherical lipid vesicles consisting of phospholipid bilayers that improve the efficacy of the drugs by fusing with biological membranes, and eventually releasing their entrapped content into the cells or bacteria. The aim of this study therefore, is to develop a new bacitracin-based controlled release hydrocolloid dressing, with good absorptive properties for improving the efficacy of antibiotics in wound healing. HPLC (high-pressure liquid chromatography) assay of bacitracin was performed for quantification of the drug. Liposomes were prepared using thin film hydration and extrusion methods. Liposomes were also characterized based on their ideal particle size and encapsulation efficiency, and then incorporated into the different ratios of chitosan/gelatin hydrocolloid films. The films were prepared with increase in gelatin concentration and were evaluated for folding endurance, tensile strength, water absorption capacity, morphology, drug release kinetics, antimicrobial activity and stability. The morphology of these films was found to be very smooth and homogeneous proving a good compatibility between the two polymers. With increase in gelatin concentration, folding endurance, water absorption capacity, tensile strength, drug release kinetics and antimicrobial activity were increased. The antibacterial activity against various bacterial species was improved in the bacitracin loaded hydrocolloid films as compared to the blank films. Based on the findings above, it can be concluded that chitosan/gelatin films at 1:3 proportion is a successful wound dressing for wound management with improved wound healing properties than other formulations. This formulation is a potential candidate for the development of alternative pharmaceutical dosage forms, for the treatment of bacterial infected wounds, based on the activity of the eco-friendly chitosan matrix added to the bacitracin activity. In this work, chitosan also demonstrated a great potential as a dressing for advanced wound therapy and confirmed its good biocompatibility and potential to provide, in combination with liposomes, sustained drug release which is highly beneficial for wound treatment. The addition of gelatin improved the water affinity of the films and facilitated water mediated cross-linking process.
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- Date Issued: 2017
Devulcanization of model compounds by a variety of diphenyldisulfides
- Authors: Boyce, Annemè
- Date: 2017
- Subjects: Rubber -- Recycling Rubber, Reclaimed , Rubber -- Standards -- South Africa Rubber -- Research Chromatographic analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/14730 , vital:27834
- Description: Improvements to the properties of recycled rubber, by developing a more selective breakdown process, is an important issue and a global challenge. Devulcanization is the most promising way to achieve this. It is a process which aims to totally or partially cleave monosulfidic (C-S-C), disulfidic (C-S-S-C) and polysulfidic (C-Sx-C) crosslinks of vulcanized rubber. In this study, the devulcanization of sulfur-vulcanized natural rubber with a variety of diphenyldisulfides has been studied using 2,3-dimethyl-2-butene and squalene as model compounds, vulcanized by sulfur and 2-bisbenzothiazole-2,2’-disulfide. 2-aminodiphenyldisulfide; 4-amino-diphenyldisulfide; bis(2-benzamido-)diphenyldisulfide and 2,2’-bithiosalicylic acid were used as aromatic disulfides devulcanization agents. Thermal analysis was used to investigate interactions between various combinations of curatives in the vulcanization systems in the absence of model compounds. Thermogravimetric analysis was used to detect mass changes during vulcanization and whether the samples decompose/evaporate so as not to contaminate differential scanning calorimetry instrumentation. Differential scanning calorimetry was used to investigate reactions occurring between curatives. Comparison of reversing and non-reversing signals in modulated experiments are suggestive of reactions between devulcanization agents and sulfur, and accelerators Vulcanization of the model compounds were performed in 10m evacuated sealed glass ampoules placed in an oil bath at 160 °C and agitated for the duration of vulcanization. After 60 min the ampoules were removed and quenched. These were then devulcanized by exposure to a devulcanization agent in a sealed ampoule at 180 for 60 min. Crosslinked 2,3-dimethyl-2-butene species were isolated and analysed by reversed phase high performance liquid chromatography. Particular attention was paid to changes in the number of sulfur atoms in the crosslinks. Results indicate that of the devulcanization agents tested 4-amino-diphenyldisulfide was the most effective. No detrimental effect on devulcanization efficiency was caused by the substitution of a basic amino group with an acidic carboxylic acid group Gel permeation chromatography was performed on devulcanized squalene crosslinks using a tetrahydrofuran eluent. GPC investigations with squalene were less effective than HPLC experiments with 2,3-dimethyl-2-butene at evaluating the relative efficiency of individual devulcanization agents. Results were, however, consistent with 4-amino-diphenyldisulfide again being the most efficient devulcanization agent.
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- Date Issued: 2017
Dietary diversity amongst adults who buy at shopping malls in the Nelson Mandela Bay area
- Authors: De Bruin, Eunice Mari
- Date: 2017
- Subjects: Nutrition -- South Africa -- Port Elizabeth , Older people -- Nutrition Diet Food security -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/15027 , vital:28114
- Description: Background: Assessing the level of dietary diversity and contributing factors that influence the level of dietary diversity amongst adults can highlight gaps in nutrition interventions, policies and programmes, which aim at combating the double burden of malnutrition. Aim: The aim of this study was to determine which factors and relationships affect the level of dietary diversity of adults in the Nelson Mandela Bay area. Design: An exploratory comparative, cross-sectional, quantitative study design with a qualitative component that was utilised. Both interviewer- and participantadministered questionnaire sections were applied. Data were analysed using IBM SPSS Statistics, Statistica Version 12, Microsoft Office Excel 2007, Spearman rho correlation co-efficient and Pearson’s chi-square test (p-value <0.05). Participants and setting: A convenience-stratified sample (n=480) was used, consisting of adults who reside and shop at shopping centres in the Nelson Mandela area, after obtaining informed consent. Results: The findings indicated that adults in the Nelson Mandela Bay area who shopped at shopping malls had a medium level of dietary diversity. The dietary patterns found were not in line with the South African Food Based Dietary Guidelines. The most consumed food items were ‘cereals' (95%), 'sweetening agents and sweets' (89%) and ‘spices, condiments and beverages’ (87%). Fruit (45,2%) and vegetables (64,8%) were generally poorly consumed. Significance was shown as having an effect on the level of dietary diversity for factors such as ethnicity, level of education, amount of money spent on food purchase per month, distance travelled to purchase food, and nutrition knowledge. Conclusion: The study suggests that adults living in the Nelson Mandela Bay area have a medium level of dietary diversity, with practices that are not in line with the recommended South African Food Based Dietary Guidelines. Strategies, including nutrition education promotion and the implementation of current policies, programmes and interventions, should be implemented and/or strengthened to encourage behaviour change.
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- Date Issued: 2017
Differential regulation of wheat (Triticum aestivum) callose synthases during Russian wheat aphid (diuraphis noxia)infestation
- Authors: Ngwenya, Nompilo
- Date: 2017
- Subjects: Russian wheat aphid Wheat -- Diseases and pests
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8100 , vital:31522
- Description: Plant production serves as the primary food source for all living beings and is continuously being affected by many biotic and abiotic factors. Wheat, one of the most consumed cereal crops in the world and the second most cultivated crop after maize in South Africa, is continuously being affected by Russian wheat aphid (RWA) since 1978. To counteract the effect of this aphid, the first resistant wheat cultivar was developed in 1984 in South Africa containing the Dn1 resistance gene. However, the mechanism of action of the resistance is still not fully understood to date. The feeding of the RWA on the wheat induces callose deposition especially in susceptible wheat cultivars, linking the β-1.3-polysaccharide (callose) to the resistance mechanism. Callose is synthesized by callose synthases, also known as glucan synthase-like genes (GSL). Not much is known about the mechanism of action of callose synthases or how they are regulated in response to the RWA. Bioinformatics tools, such as those available at NCBI, were used to identify the wheat callose synthases genes. The proteins encoded by the identified wheat callose synthases genes, were then analyzed for conserved domain motifs using the MEME suite and InterproScan, sequence similarities using ClustaL Omega and transmembrane domains using HMMTOP and ProtCamp. These were then compared with those of the already characterized Arabidopsis callose synthase proteins in an attempt to identify the wheat callose synthase(s) that responds to aphid feeding. Further bioinformatics studies were carried out to identify the presence of biotic stress associated cis-acting regulatory elements found in the 1.5 kbp upstream region of the start codon of the Arabidopsis callose synthase genes. Eight partial wheat callose synthase sequences were identified and two of these (TaGSL2 and TaGSL22) showed high similarities to the AtGSL5, which is up-regulated in response to aphid feeding in Arabidopsis. Six of the wheat callose synthase genes were mediated to code for the functional callose synthases proteins: TaGSL3, 8, 12, 19, 22 and 23, and analyzed for conserved protein motifs. Based on the sequence similarities and conserved protein domains, TaGSL2 and TaGSL22 were found to be the most similar to AtGSL5 and most likely to respond to RWA infestation. Cis-acting regulatory element analyses confirmed the possibility of TaGSL22 being responsible for callose deposition in wheat as biotic stress associated cis-acting regulatory elements, Box W1, TC- rich element and W- box were all found in the 1.5 kbp upstream of the TaGSL22 coding region. Callose was quantified in both susceptible and resistant wheat cultivars using the aniline blue fluorescence method. When infested with RWA-SA1, the susceptible wheat cultivar (Tugela) deposited significantly higher amounts of callose, compared to the resistant wheat cultivar (Tugela DN), which deposited little, to no callose with respect to the control samples. Transcription analysis, of the TaGSL2 and TaGSL22 in RWA-SA2 infested Tugela and Tugela DN wheat cultivars, was performed using real time polymerase chain reaction (qPCR). Both TaGSL2 and TaGSL22 genes were up-regulated in Tugela and Tugela DN wheat cultivars in response to RWA-SA2 infestation, with TaGSL22 being more expressed than TaGSL2 in both cultivars, indicating that RWA-SA2 is able to overcome the resistance of Tugela DN and cause callose deposition. However, significantly higher expression of both genes was still observed in the susceptible, Tugela wheat cultivar. This study therefore confirms that callose deposition is associated with RWA-SA1 feeding, only in the susceptible wheat cultivar, Tugela and not the resistant cultivar, Tugela DN. However, during RWA-SA2 feeding, two of the eight identified callose synthases in wheat, are up-regulated in response to RWA-SA2 feeding, in both the resistant and susceptible wheat cultivars with higher levels observed in the susceptible wheat cultivar when compared to the resistant wheat cultivar. TaGSL2 and TaGSL22 are therefore implicated in the callose deposition observed in the susceptible and resistant wheat cultivars, after RWA-SA2 infestation. Further studies are required to confirm the differential regulation of the two wheat callose synthases proteins during RWA infestation and their possible role in the resistance mechanism of the resistant wheat cultivar, Tugela DN.
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- Date Issued: 2017
Dinoflagellate communities in Algoa Bay: abundance and dynamics
- Authors: Van Zyl, Hendrik Francois
- Date: 2017
- Subjects: Marine microbiology , Microbiology Marine biology -- Indian Ocean
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/21218 , vital:29457
- Description: The contribution of dinoflagellates to the phytoplankton of Algoa Bay is largely unknown. This study aimed to address this, but additionally considered seasonal and spatial variation in the dinoflagellate communities of Algoa Bay. Phytoplankton abundance and the inorganic nutrients ammonium, total oxidized nitrogen, soluble reactive phosphorus and silicate were analysed. Diatoms dominated the phytoplankton community in most samples, with dinoflagellates only occasionally dominating the community. No seasonality could be detected in dinoflagellate abundance. Furthermore, no significant spatial patterns could be distinguished in dinoflagellate abundance, with the only exception being that the Port Elizabeth harbour waters contained significantly fewer dinoflagellate cells than the younger Ngqura harbour. Total phytoplankton abundance was correlated with inorganic nitrogen concentrations, but this was due to diatoms – dinoflagellate abundance did not correlate significantly with any nutrient measured. Both the common, historically bloom-forming Noctiluca scintilans, as well as the recently red tide-forming Lingulodinium polyhedra were recorded during the study, the latter almost exclusively from the harbours, which can be considered repositories of these toxic and harmful algal cells. The findings suggest that dinoflagellates in Algoa Bay are a robust phytoplankton group able to survive, and often thrive, in wide range of environmental conditions.
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- Date Issued: 2017
Diurnal and nocturnal activity patterns and habitat use of Algoa Bay’s rocky reef fish community
- Authors: Juby, Roxanne
- Date: 2017
- Subjects: Reef fishes -- Effect of light on , Reef fishes -- South Africa , Underwater videography in wildlife monitoring -- South Africa -- Tsitsikamma
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/44827 , vital:25445
- Description: Distinct day-night changes in ambient light are recognised as an important driver of animal activity patterns, with predictable changes to the structure and composition of animal communities between day and night. While day-night variation in the structure of animal communities has been well researched for terrestrial organisms and shallow marine fish communities around the world, there has been limited research of this type conducted on South Africa’s rocky reef fish communities. Consequently, we have a poor understanding of how nocturnal reef fish communities are structured and the day-night activity patterns of species inhabiting both shallow (10-30m) and deep-aphotic (55-100m) reefs. This research was conducted at two warm-temperate South African rocky reefs situated in Algoa Bay. The importance of natural ambient light in shaping the distribution of reef fish communities at shallow and deep-aphotic reef sites was demonstrated using baited remote underwater stereo-video systems (stereo-BRUVs). Distinct day and night fish communities were sampled at shallow and deep-aphotic reef sites. These differences were driven by significant changes in species richness (p < 0.001), species abundance (p < 0.001) and community composition (p < 0.001). These shifts appeared to be driven by day-night activity patterns that were the result of increased detectability of certain species at either day or night. The majority of species belonging to the family Sparidae showed evidence of strict diurnal activity, with their activity being further restricted to shallow reefs. These species showed evidence that they may enter micro-habitats within the reef at night. Similar activity patterns were shown for other top predatory teleost species and low level consumers, with substantial reductions in abundances, or no recordings at night throughout this study. Shallow reefs at day harboured the most diverse fish community. It is therefore hypothesised that this habitat was associated with conditions that offered improved access to resources for many visual species. In addition, the diverse community inhabiting shallow reefs at day is associated with a high risk of negative interspecies interactions, such as competition and predation. It is hypothesised that the biotic conditions associated with shallow reefs at day drove three movement patterns identified in this study; Pagellus bellottii natalensis showed evidence of movement onto shallow reefs at night from adjacent sandy flats, while Pterogymnus laniarius and Squalus sp. 1 showed evidence of movement onto shallow reefs at night from the deep- aphotic reefs that remain dark throughout the diel cycle. It is further hypothesised that other species which showed evidence for nocturnal activity, i.e. Galeichthys ater, Eptatretus hexatrema and Haploblepharus edwardsii, may enter sheltered micro-habitats within the reef during day light hours. These findings have highlighted the complex patterns that have evolved within marine fish to allow multiple species to coexist and exploit productive reef ecosystems by partitioning resource use and activity patterns at day or night, between depth zones and habitat types.
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- Date Issued: 2017
Early stage ichthyofauna from shallow water habitats of the Angola-Benguela frontal zone
- Authors: Farthing, Matthew William
- Date: 2017
- Subjects: Fishes -- Larvae -- South Africa -- Atlantic coast , Fishes -- Larvae -- Angola -- Atlantic coast , Striped mullet -- Angola -- Atlantic coast
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/50442 , vital:25988
- Description: Early stage fishes (larvae and early juveniles) were collected from an array of shallow water (±1.5m) habitats on the warm-temperate southern Angolan coastline between June 2014 and June 2015. This study, the first assessment of the early stages of coastal fishes in Angola, provides important new understanding of non-estuarine shallow water nursery habitat use by coastal fishes from the region. In total, 51 species from 18 teleost families were observed. The exposed surf zone was dominated by postflexion larvae, while the moderately exposed beach and sheltered bay were dominated by early juveniles. Both fish density and diversity peaked in the wet season (Feb – Apr 2015) for all habitats, attributed to the influx of summer spawning species. Diplodus sargus dominated catches from the exposed surf zone, and the timing of observations supports the growing consensus that sparid spawning is dictated by temperature, not season. The similitude of the observed species to those observed in warm temperate South Africa highlights the historical connection of the warm-temperate study area with warm-temperate South Africa, prior to the formation of the Benguela Current as a vicariant barrier. The classification of the study assemblage into established estuarine utilization categories showed that the surf zone hosted more exclusively marine species than comparable surf zones in South Africa, attributed to the absence of estuaries in southern Angola. However, the observation of the marine estuarine dependent Mugil cephalus in this study area devoid of estuaries suggests that estuarine dependency may be regionally specific for some taxa. It appears that the warm, sheltered, nutrient rich waters of Tombua Bay provide typically estuarine associated taxa with a suitable alternative, non-estuarine nursery habitat. This study provides evidence that the importance of estuaries as critical nursery habitats has been overemphasized for some warm-temperate coastal fishes. However, the absence of other marine estuarine dependent species from the study area suggests that some warm-temperate taxa do intrinsically rely on estuarine function for survival.
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- Date Issued: 2017
Ecosystem engineering by the wetland plant palmiet: does it control fluvial form and promote diffuse flow in steep-sided valleys of the Cape Fold Mountains
- Authors: Barclay, Amy
- Date: 2017
- Subjects: Prionium serratum , Wetlands -- South Africa -- Eastern Cape , Aquatic plants -- South Africa -- Eastern Cape , Peatland ecology -- South Africa -- Eastern Cape , Kromme River (Eastern Cape, South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4646 , vital:20708
- Description: Ecosystem engineering refers to the way that organisms control the structure and function of ecosystems. It has been suggested that palmiet (Prionium serratum, Thurniaceae) works as an ecosystem engineer, shaping peat wetlands in South Africa. However, there is currently a paucity of evidence supporting this claim. Palmiet has a dense root, rhizome and stem system that forms dense stands, growing from channel banks into fast flowing river channels. This slows river flows, traps sediment, which builds up riverbeds and ultimately blocks river channels, turning the river into a wetland. The aim of this study was to determine if palmiet is an ecosystem engineer and to document its pattern of colonisation and the nature of its control of a fluvial system. This was achieved by undertaking vegetation surveys in the Kromrivier Wetland in the Eastern Cape. The data was analyzed using vegetation classification and ordination, where vegetation communities were linked to environmental factors. It was found that palmiet occupied three distinctive habitats; 1) on near-horizontal valley- bottom habitats filled with sediments that are a mixture of autochthonous organic sediment and allochthonous clastic fines, 2) the bed of gullies that have recently filled with coarse grained clastic sediment, and 3) open water bodies. Three conceptual models were developed, one that accounts for the process of gully bed colonisation, sediment trapping and gully filling, another involving rapid colonisation of sedimentary fill from tributary sediment sources that block a gully, and the third involving colonisation of open-water areas that form in former gullies upstream of the blockage. The study suggests that the wetland has been characterised by repeated cutting and filling cycles, despite which, palmiet has repeatedly reinstated diffuse flow conditions across the valley floor. Palmiet was indicated to exert a key control on fluvial form and dynamics of the wetlands in the Kromrivier valley.
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- Date Issued: 2017
Effect of graphitization on the static mechanical properties of service exposed ASTM A516 Gr. 65 steam pipe metal
- Authors: Du Preez, Christiaan
- Date: 2017
- Subjects: Graphitization Steam-pipes -- Mechanical properties
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/22277 , vital:29933
- Description: The focus of this research project is to establish what effect graphitization has on the static mechanical properties of service exposed ASTM A516 Grade 65 steam pipe material, which operated for prolonged periods above 425 ̊C. The research study was conducted on three graphitized service exposed steam pipe weldment samples and on a newly welded and post weld heat treated sample with graphitized service exposed steam pipe material. Macro samples were removed from each of the samples at two positions and these were evaluated with regard to graphite nodule size, nearest neighbour spacing and % planar graphitization in the parent pipe and HAZ regions on either side of the welds. It was found on all of the service exposed samples that the graphite nodules of the HAZ regions have a smaller median nodule size, smaller median nearest neighbour spacing and increased % planar graphitization in comparison to the parent pipe material. The service expose parent pipe material on either side of the weldments of the respective samples was chemically analyzed. This was done with the focus being on the deoxidizing element content (Si and Al) of the respective parent pipe regions and to what extent these elements influenced the development of planar graphitization in these regions. No correlation could be identified between the level of deoxidizing elements and the levels of % planar graphitization in the parent pipe material. Tensile and Charpy impact samples were removed from the respective service exposed samples parent material on either side of the weld and from the HAZ regions on the side with the highest levels of planar graphitization. These samples were tested and the yield and ultimate tensile strength and Charpy impact toughness of the respective samples were then evaluated to establish how these static mechanical properties were influenced by the % planar graphitization. The yield and ultimate tensile strength of the service exposed material did not show a statistically significant correlation with the % planar graphitization. The Charpy impact toughness results did however show a statistically significant negative correlation towards the % planar graphitization. This was clearly evident from the results of the HAZ regions of the service exposed weldments (Samples A-C) which had the highest levels of % planar graphitization and the lowest impact toughness, while the newly welded and post weld heat treated Sample D had no planar graphitization outside the HAZ and the highest impact toughness. This research project not only investigated how planar graphitization affects the static mechanical properties of service exposed pipe material, it also investigated on a microstructural basis, how planar graphitization nucleates and grows. The microstructural investigation showed that the free carbon required for the development of planar graphitization originated from the regions outside the HAZ, which were formed when the pearlite bands were dissolved during the welding of the steam pipe. The heat input from the welding sensitized this region for the development of planar graphitization, probably due to the formation of a “carbon-rich” matrix due to the partial dissolution of the cementite precipitates. All the carbide precipitates in this region consisted of M3C. aluminium-rich precipitates were found inside newly nucleated graphite nodules, indicating its role as a possible heterogeneous nucleation site. Growth of newly formed graphite nodules showed a preference towards high-angle grain boundaries and regions with dislocations for the initial growth stages of the graphite nodules. The microstructure of the region outside the HAZ of the newly introduced seam weld on the service exposed steam pipe material (with graphitization), was also investigated using advanced electron microscopy methods and it yielded no evidence of the development of planar graphitization.
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- Date Issued: 2017
Effective communication planning for high-performance civil engineering project teams
- Authors: Rossouw, Jeanne Jacques
- Date: 2017
- Subjects: Communication in engineering -- South Africa Communication of technical information , Communication in management Project management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/19993 , vital:29020
- Description: In the area of project management, it is well understood that effective communication processes impact positively on project performance. Despite this, project teams still struggle to develop effective communication plans that address their project communication needs. The evidence of this is that many project problems are attributed to poor communication. The literature addresses the needs and shortcomings of group communication and communication planning in general; but there is however, a scarcity of literature describing how to plan for the internal communication needs of high-performance civil engineering teams. With the limited literature available on the topic, this study seeks to validate how effective the current communication planning methods are at Aurecon in meeting the communication needs of its project teams. This qualitative research project is a case study of communication planning within the project teams at Aurecon in Port Elizabeth. A semi-structured interview process was followed, addressing specific questions, without limiting the direction of the interviews. Project team members, working on high performance projects, were asked for their thoughts, feelings and suggestions about existing communication practices and project communication planning. Overall, it was found that the existing communication-planning practices at Aurecon did not have any beneficial effect on how team members communicate. It was concluded that project teams would benefit from improved communication-planning processes that are more inclusive of their specific communication needs. Organisations working on high-performance projects will benefit directly from the research, which challenges these organisations to think more broadly about how they plan for communication at a project level. The research provides practical suggestions for improving the way that teams plan their communication processes; and it does so by focusing on the communication needs of the team members. Recommendations are made to professional bodies, tertiary institutions, project organisations – and most importantly – to project team members themselves. The recommendations to project team members include taking ownership of communication practices, asserting their views, as well as making their needs known.
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- Date Issued: 2017
Effects of loading time and lairage duration on pig behaviour, sex and lairage time on pork physio-chemical characteristics
- Authors: Ntlatywa, Bongiswa
- Date: 2017
- Subjects: Pork -- Quality Meat -- Quality Loading and unloading
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12270 , vital:39225
- Description: The objectives of the study were to determine the effect of loading time, transportation unloading and lairage period, their subsequent effect on responses behaviour and the effect of sex and lairage period on the meat quality of cross breeds reared in commercial farm. The first part of the study assessed the behaviour of pigs during loading at the farm, offloading and in the lairages. A total of 900 pigs from 5 trips (180 per trip) were monitored on behaviour from farm to slaughter plant. The pigs were transported to a commercial abattoir which is 120 km distance, travelling for 2 hours from the farm. The results revealed that time spent in loading pigs was more than when offloading pigs. The frequency of slipping or falling-off in pigs was high (18percent) than voluntary movement (8percent) during loading times (χ2 >0.05) that when off-loading. A significant difference was determined on the avoidance (χ2=0.03), mounting behaviour (χ2 =0.01) and vocal sound (χ2 =0.02) during loading time on each observation day. Furthermore there was no significant difference determined on the time and day of observation in the lairages. These results also reveal that the avoidance behaviour was the highest (47percent) while fighting (34percent) and vocalizing were the least compared to other behaviour during the first 30 minutes after arrival at the abattoir. Moreover, the lying behaviour was found to have highest frequency (15percent) on day 6 compared to other sampling days. These results reveal that time of loading pigs had an influence on pigs’ behaviour before slaughter and consequently that affected physiological features and meat quality. The second section of the study assessed sex and the different lairage time effects on the pork quality attributes. A total of fifty four pigs, 22 weeks old of different sex (26 boars x 28 gilts) reared on a commercial farm and transported to the abattoir on the same day was used in this study. At the abattoir, pigs were grouped according to lairage periods of 17 hours (Group1; 13 gilts and 14 boars) and 36 hours (Group 2; 15 gilts and 12 boars). Results showed no significant difference on the sex of pigs (P >0.05) and meat pH. However, lairage time influenced the thawing loss (P= 0.02) of meat and also the interactions of sex by lairage had a significant difference (P= 0.04) on meat tenderness. There was a positive significant correlation found between sex and meat attributes values were high in boars (r= 0.61) than in gilts (r = 0.49). A negative correlation between a*and WBSF on lairage group1 (r= -0.52) was determined while on group 2 there was a positive correlation between a* and b* (r=0.49). This study suggest that a proper timing on farm feed withdrawal in combination with a sufficient lairage at the slaughter plant may result in better carcass and meat quality traits. Communication among producers and abattoirs is critical when planning the fasting and lairage times in order to elude carcass and technological pork quality complications. To conclude, there is influence caused by time of loading in stressing pigs before transportation and slaughter as aggressive behaviour showed and also lairage time affected meat quality.
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- Date Issued: 2017
Elephant space use and impacts on vegetation in response to habitat expansion in succulent thicket
- Authors: Lochner, Christiaan Stefanus
- Date: 2017
- Subjects: Grasses -- South Africa -- Addo Elephant National Park , Vegetation mapping -- South Africa -- Addo Elephant National Park Nature conservation -- South Africa -- Addo Elephant National Park Ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/18597 , vital:28687
- Description: Elephant alter vegetation composition and structure, and at high densities biodiversity declines. While habitat expansion is one of several tools proposed to mitigate such effects, its effectiveness remains untested. Despite previous incremental expansions of the Addo Main Camp section of the Addo Elephant National Park to reduce the impacts of elephant on vulnerable Succulent Thicket habitats, significant declines in plant species richness, density and biomass were recorded. During 2010 the addition of the Colchester section effectively doubled the area (120 km2 to 230 km2) available to elephant, presumably releasing browsing intensity in the Addo Main Camp section, hence allowing for the regeneration (through growth and resprouting) of the vulnerable canopy shrubs (a key functional guild). I aim to test this hypothesis. I use space use data from before and after expansion to track the distribution of elephant utilization across the park. Additionally, I use data collected between 2008 and 2015 on shrub composition and structure and the structure of individual canopy species, to illustrate the long-term trends in elephant impact. I firstly show that although elephants shift a proportion of their utilization distribution into novel habitat, they continue to show a strong preference for the Addo Main Camp section, with its higher water availability yet heavier utilized vegetation. I also illustrate that within 5 years of the expansion, effects on the canopy shrub community declined, presumably by spreading impacts to novel areas. Specifically, I show that vegetation composition and structure (volume and density) remained stable during this period. While these results indicate that range expansion might be a viable tool to mitigate the impact of elephant on vegetation composition and structure, at least in the short-term, the consequences for ecological functioning remain to be measured. In the long-term, I predict that attempts to use range expansion as a management tool may fail if implemented without limiting population numbers and controlling the distribution of local densities (e.g. by managing surface water availability).
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- Date Issued: 2017
Estimating maize grain yield from crop growth stages using remote sensing and GIS in the Free State Province, South Africa
- Authors: Mditshwa, Sithembele
- Date: 2017
- Subjects: Crop yields Crops -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6016 , vital:29481
- Description: Early yield prediction of a maize crop is important for planning and policy decisions. Many countries, including South Africa use the conventional techniques of data collection for maize crop monitoring and yield estimation which are based on ground-based visits and reports. These methods are subjective, very costly and time consuming. Empirical models have been developed using weather data. These are also associated with a number of problems due to the limited spatial distribution of weather stations. Efforts are being made to improve the accuracy and timeliness of yield prediction methods. With the launching of satellites, satellite data are being used for maize crop monitoring and yield prediction. Many studies have revealed that there is a correlation between remotely sensed data (vegetation indices) and crop yields. The satellite based approaches are less expensive, save time, data acquisition covers large areas and can be used to estimate maize grain yields before harvest. This study applied Landsat 8 satellite based vegetation indices, Normalized Difference Vegetation Index (NDVI), Soil Adjusted Vegetation Index (SAVI) and Moisture Stress Index (MSI) to predict maize crop yield. These vegetation indices were derived at different growth stages. The investigation was carried out in the Kopanong Local Municipality of the Free State Province, South Africa. Ground-based data (actual harvested maize yields) was collected from Department of Agriculture, Forestry and Fisheries (DAFF). Satellite images were acquired from Geoterra Image (Pty) Ltd and weather data was from the South African Weather Service (SAWS). Multilinear regression approaches were used to relate yields to the remotely sensed indices and meteorological data was used during the development of yield estimation models. The results showed that there are significant correlations between remotely sensed vegetation indices and maize grain yield; up to 63 percent maize yield was predicted from vegetation indices. The study also revealed that NDVI and SAVI are better yield predictors at reproductive growth stages of maize and MSI is a better index to estimate maize yield at both vegetative and reproductive growth stages. The results obtained in this study indicated that maize grain yields can be estimated using satellite indices at different maize growth stages.
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- Date Issued: 2017
Evaluating the importance of mangroves as fish nurseries in selected warm temperate South African estuaries
- Authors: Muller, Cuen
- Date: 2017
- Subjects: Mangrove ecology -- South Africa Mangrove fisheries -- South Africa , Estuarine ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/12080 , vital:27029
- Description: The value of mangrove habitats as fish nurseries was assessed by comparing communities of early stage and juvenile fishes between estuaries with and without mangroves. Early stage fishes were sampled using boat-based plankton towing while juveniles were sampled by seine netting. Sampling took place at five sites spaced 1 km apart starting near the estuary mouth in four estuaries along the temperate coastline of the Eastern Cape Province of South Africa. Four estuaries were selected based on shared similarities which included catchment area, estuarine area and shared habitats barring the presence of mangroves which occupied the river margins of two systems. Results revealed that early stage and juvenile fish communities (both marine- and estuary-spawned) were similar between systems with and without mangrove habitats. Differences in fish communities among estuaries were rather attributed to axial salinity gradients associated with greater freshwater input, while season and temperature produced significant variances in fish densities with Generalised Additive Models revealing responses of communities to these variables. A common estuarine-dependent fish, Rhabdosargus holubi (Family Sparidae), was further investigated to determine habitat use, residency and dietary patterns in different mangrove habitats. High habitat residency in this species was revealed during a short-term tagging study using Visible Implant Elastomer tags and long-term isotope analysis in juveniles sampled from two contrasting mangrove habitats. A wider feeding niche was observed in an eelgrass-red mangrove connected habitat when compared with more exposed white mangrove areas. Low dependence on mangrove habitats in temperate estuaries is likely due to their tidally dominated inundation and limited refuge potential due to smaller area coverage by mangroves in temperate estuaries. Relatively lower primary productivity in warm temperate mangrove areas, relative to their tropical counterparts, provides no significant feeding advantage or refuge opportunities relative to other available habitats in these estuaries. Warm temperate estuaries, which are both spatially and temporally highly variable, instead host species which are habitat generalists, able to capitalise on these highly dynamic environments.
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- Date Issued: 2017
Evaluation of groundwater potential using neotectonics and geophysics in the context of post Karoo tectonic framework around Fort Beaufort and Smithfield, Eastern Cape, South Africa
- Authors: Ndlovu, Nkosilathi
- Date: 2017
- Subjects: Neotectonics -- South Africa -- Eastern Cape Groundwater -- South Africa -- Eastern Cape Geophysical surveys -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12687 , vital:39299
- Description: Geological and geophysical methods were used to investigate the Karoo area extending from longitudes 25.50 E to 27.50 E and latitudes 300 S to 330 S in South Africa, particularly Fort Beaufort, Aliwal North, Venterstad and Smithfield. The geology of the area is dominated by the upper Beaufort Group (Adelaide Subgroup) with an extensive network of dolerite sills and dykes that intruded the sedimentary sequence. A relationship between neotectonics, post-Karoo tectonics, groundwater and lithology was investigated to locate suitable groundwater potential sites. Apart from studying the role of neotectonics and the post Karoo tectonics, this research aims at generating groundwater targets to alleviate water shortages mainly for farming and livestock, and prove that neotectonics is still active. Methodologies adopted for obtaining these results included a comprehensive literature review, thin section analysis, scanning electron microscopy, geophysical investigation (magnetic, gravity, and vertical electrical sounding), and the application of Geographical Information Systems (GIS) and remote sensing. Twenty samples were collected at various locations within the study area and were analyzed using the petrographic microscope while others were analyzed with the Scanning Electron Microscopic (SEM) combined with an Energy dispersive x-ray spectrometry. The results show that the rocks are fractured, porous and have variable mineralogy (presence of heavy minerals) within the rocks. The use of Geographical Information Systems (GIS) and remote sensing in geological surveys, especially hydrogeology, has gained momentum over the past few years. This research is no exception as ArcMap software was used to create a map of seismic epicentres of the Eastern Cape Province. From the map it can be observed that seismicity still occurs and thus leading to the notion of neotectonics being active. Lineaments were also automatically extracted using the ENVI 5.1 and Geomatica 2013 software. Lineaments are zones of weakness in the subsurface of the Earth and are very important in locating groundwater potential sites. Geophysical techniques are essential and highly accurate for groundwater studies. Gravity and magnetic techniques were applied on data which was supplied as grids. Analysis using Geosoft Oasis 8.3 revealed extensive lineaments and ring like patterns and these were inferred to be dolerite intrusions (sills and dykes). The morphology of the intrusions help in identifying possible groundwater potential zones and thus they should be investigated. Vertical electrical sounding (VES) technique using the Schlumberger array was carried out at three sites (Fort Beaufort fracture which is possibly related to Quaternary surface uplift of the Amatole-Swaziland axis, splay of the Fort Beaufort fracture and at a site which showed high groundwater potential) to explore subsurface layering. IP2win (lite), 1-D modelling software was used to model the apparent resistivity data to obtain the geoelectric parameters of the subsurface (thickness and resistivity). The VES results are consistent with fractured rocks that aid groundwater movement. The VES data for the three sites was further modelled by the RES2DINV software and this shows low resistivity values associated with loose, water saturated top sandy soil and higher resistivity values associated with sedimentary sequences and dolerite. Moreover, potential sites for citing wells are predicted to be between 79.5 and 128 m on the profile. Further neotectonic studies need to be done, especially on the quaternary sediments as they would have more neotectonic evidence. The use of geophysical techniques for groundwater search need to be intensified, with more emphasis being put to the sedimentary sequences bordered by dolerite intrusions and fractured zones.
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- Date Issued: 2017
Evaluation of low-cost technology options for sustainable water supply and sanitation in two peri-urban areas of Lusaka, Zambia: opportunities and constraints
- Authors: Chiliboyi, Yvonne
- Date: 2017
- Subjects: Toilets -- Technological innovations -- South Africa , Sanitary engineering -- Technological innovations -- South Africa , Water resoures development -- Technological innovations -- South Africa , Water-supply -- Technological innovations -- South Africa , Household surveys -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/7960 , vital:21328
- Description: Presently, at least 70% of the total urban population in Zambia resides in peri-urban areas. Peri-urban settlements are characterized by high population growth, high poverty levels and inadequate access to water and sanitation which often result in increased prevalence of diseases. The situation is even made worse because of the position that many local authorities have taken regarding the implementation of infrastructure and service development in these settlements. Local authorities in developing countries have continuously focused on implementation of traditional and unsustainable technologies for service provision to meet the demand despite the technologies’ inability to serve the rapidly growing peri-urban areas. These technologies have high costs, lack proper operation and maintenance, and are not affordable to majority of peri-urban residents. Therefore, this study was set out to identify and evaluate the existing and possible low-cost technology options for sustainable water supply and sanitation in two selected peri-urban areas of Lusaka, Zambia, namely Kanyama and Chazanga. This was achieved through a household survey conducted in the selected communities. Questionnaires and focus group discussions were held in the respective areas to obtain baseline data on the current water supply and sanitation situation, the type of technologies used, challenges faced regarding water and sanitation technologies, and to get the communities perceptions and preferences of different technology options. Thereafter, a Multi-Criterion Analysis methodological approach was used to assess the selected technologies by the communities, taking into consideration of the economic, socio-cultural, technical, institutional and environmental aspects. Results from the study revealed that a few low-cost water supply and sanitation technologies are feasible for peri-urban areas. For Chazanga, communal taps, boreholes, protected wells, and rain water harvesting were found to be feasible for water supply. For sanitation, on-site sanitation services such as compost toilets, dry toilets, as well as Ventilated Improved Pits (VIP) and Pour-flush, Fossa Alterna and the Urine Diversion Dry Toilet (UDDT) are some of the low-cost technologies that can be implemented in the area. The VIP is suitable for households that rely on water from communal taps for their use. As majority of households in the area have taps on their plots, the Pour-flush can be an alternative. The Fossa Alterna and the Urine Diversion Dry Toilet (UDDT) have low initial cost and can accommodate different households. Additionally, the area has a lower household size and majority of the residents in the area landlords, which makes it easy to teach users how the toilet operates as well as its maintenance. For Kanyama, feasible and sustainable low-cost water supply facilities include boreholes and communal taps. Kanyama has limited plot sizes thereby causing the challenge of implementing infrastructure such as rainwater harvesting. Additionally, continuous increase in urban population in the area, coupled with the construction of unregulated households and sanitation facilities, renders protected wells not feasible to implement in Kanyama. In terms of sanitation, wet on-site sanitation facilities such as Ventilated Improved Pit (VIP) latrines are accepted by the community. The VIP does not require water for use and if properly constructed can be used as a bathroom. The Pour-flush toilet is also another alternative for provision of sanitation in the area. However, the latrine can be expensive to construct for majority of the residents. Dry sanitation such as the Urine Diversion Dry Toilet (UDDT) is not feasible for Kanyama. The UDDT requires continuous awareness on its use especially in rented households where tenants are constantly changing. The method of evaluating appropriate technology options for peri-urban areas and thereafter letting the users from the communities choose from the proposed technologies ensures a participatory approach. Results from Multi-Criterion Analysis (MCA) showed that stakeholders’ influence is essential for the selection of sustainable technology options. However, it is important that the implementation process of any technology in peri-urban areas consider different aspects including the local environmental, socio-cultural, economic, technical, and institutional conditions. Finally, the outcome of this study will not only provide baseline data for successful implementation of appropriate low-cost water supply and sanitation technology options in Chazanga and Kanyama, but also other peri-urban communities in Zambia.
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- Date Issued: 2017