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Genetic Diversity And Screening Of Cowpea (Vigna unguiculata L. Walp.) Genotypes For Drought Tolerance In South Africa
Get PDFThesisA survey was carried out to assess the farmers’ production constraints, traits and preferred cowpea varieties. A semi-structured questionnaire was used in a survey in Buhera District, Zimbabwe, in March and April of 2018. Women farmers dominated the survey as they were 52% of the surveyed population, while men occupied 48% of the total population. All participants concurred that cowpeas were used for domestic consumption. Eighty-three percent of the farmers cited shortage, unavailability, and cost of fertiliser, 16% of the farmers acknowledged that they do not have access to quality seed, and 1% cited labour as the major constraints in cowpea production. Farmers ranked heat (86%), drought (10%), and soil fertility (4%) as the most important abiotic factors. Ninety-one percent of the farmers’ ranked rust as the major disease, while 2% ranked storage rot, 1% ranked anthracnose, and 1% ranked downy mildew. Eighty-one percent of the farmers ranked aphids as the main pests, while 3% ranked thrips, 3% ranked legume borers, and 2% ranked pod borers. Fifty-two percent of the farmers preferred varieties that are resistant to diseases such as rust, whereas 48% were not concerned about diseases. For qualitative traits, 50% of the farmers had no specific colour preference, 32% preferred white colour, 14% brown colour, 3% red colour, and 1% tan colour. Ninety-four percent of interviewed farmers were not concerned about the pod shape, 3% preferred the kidney shape, 2% preferred the spherical shape and 1% preferred the globular shape. Ninety-nine percent of farmers agreed that they needed high yielding varieties per unit area and only 1% were unsure. For quantitative traits such as grain size, pod size, plant height, and head size, the preferences of farmers varied. Forty-four percent of the farmer respondents preferred larger cowpea grains, while 56% were not concerned about the size of the grain. A paltry 2% of the farmers were interested in pod size, while 98% did not regard it as important. Thirteen percent of the farmers were interested in climbing varieties, while 87% considered high grain yield as of the utmost importance. The top ranked accessions were CBC1, IT 18, and “Chibundi Chitsvuku”, respectively, while the least ranked was “Kangorongondo”. The survey showed that there is a need to breed for both biotic and abiotic factors, such as drought and moisture stress, as well as against pests and diseases. In order to assess the genetic diversity and population structure among cowpea accessions, diversity arrays technology (DArTSeq) genotype by sequencing technique was used. A total of 85 cowpea accessions (45 from the International Institute of Tropical Agriculture [IITA], 25 from South Africa, and 15 from Zimbabwe) were investigated in this study using 284 single-nucleotide polymorphisms (SNPs). Fifty-one percent of SNPs were polymorphic across the 85 accessions and fulfilled the selection criteria. The genetic distance, estimated based on Nei’s index among genotypes, ranged from 0.14 to 0.44, with a mean value of 0.35. The polymorphic information content value ranged from 0.024 to 0.50, with a mean value of 0.25. Twenty-six percent of the genotypes had genetic diversity values greater than 0.40, suggesting that the genotypes were moderately genetically diversified. A high gene flow (Nm) of 4.89 was observed between Zimbabwean and South African accessions indicating the high germplasm exchange among the neighbouring countries. The analysis of molecular variance revealed highly significant variation among individual accession and low variation within individuals. The accessions showed significant (p<0.001) but low levels of differentiation among the geographic regions. Cluster analysis of the 85 accessions generated by the unweighted pair group method with arithmetic mean (UPGMA) procedure clustered the accessions into three distinct groups. The clustering patterns showed that accessions collected from the same geographic regions tend to cluster in the same groups. SNP data analysis indicated the existence of high levels of genetic diversity among cowpea accessions collected from southern Africa and Nigeria. However, the low genetic variation within individuals suggested the need to further widen the genetic base of the crop. Molecular data should be backed by morphological data to link the SNP markers that are associated with desirable agronomic attributes, such as high tolerances to biotic and abiotic stress factors. Sixty cowpea genotypes were screened for seedling drought tolerance in screen houses. Of these, 33 accessions were from the IITA in Nigeria, 19 accessions were from the Agricultural Research Council – Grain Crops in South Africa, and eight accessions were from smallholder farmers in Buhera District, Zimbabwe. Bartlett’s test of sphericity was significant at p<0.05, while the Kaiser-Meyer-Olkin measure of sampling adequacy was 77, indicating sufficient items for each factor. A principal component analysis (PC) showed that number of pods (NP), seeds per pod (SP), survival count (SC), pod weight (PWT), and stem wilting in week one (WWK1) had the most significant contributions to genetic variability in cowpea accessions to drought tolerance, as well as yield after stress imposition. Based on the PC, accessions IT 07-292-10, RV 343, and IT 95K-2017-15 had the maximum variability for NP, SP, SC, PWT, and WWK1 after drought imposition. There were significant differences among most drought-related traits at the seedling stage with the exception of environment × genotype on days to emergence (DTE), stem greenness at week 1 (SGWK1) after the imposition of water stress and also among replicates in terms of DTE. A total of 37 cowpea accessions from both screen houses were found to be tolerant to drought, while 23 were susceptible. From the results, it was observed that the accessions had similar responses to drought. The findings of the study provided a useful tool for screening and determining the accessions that are drought tolerant and susceptible at the seedling stage. Finally, it was necessary to conduct association mapping for drought tolerance at the seedling stage and yield-related traits of cowpeas. The cowpea accessions were analysed for their possible population structure using STRUCTURE 2.3.4, and the peak of delta K in the greenhouse showed the existence of seven sub- populations, whereas the peak of delta K in the glasshouse indicated the presence of six sub-populations. One SNP marker, 14083649|F|0-9 was associated with number of pods (NP) with a p value <0.001.Fifty SNP markers were associated with pod weight (PWT) at p<0.001. Four SNP markers, 14074781|F|0-16, 100047392|F|0-36, 14083801|F|0-28 and 100051488|F|0-49 were associated with ASPD at p<0.001. SNP markers, 14074781|F|0-16, 14083801|F|0-28 and 100051488|F|0-49 were associated with PL at p <0.001. Five SNP markers, 100047392|F|0-36, 14083801|F|0-28, 100072738|F|0-34, 14076881|F|0-49 and 14076881|F|0-49 were associated with PWDTH at p <0.001. The major difference that was observed in association mapping in the two environments was due to temperature variations. The 67 SNP markers identified can be used in cowpea molecular breeding to select for AVSPD, NP, PL, PWDTH, PWT, and RR through marker assisted selection (MAS)
Development And Testing Of A Model For The Formalisation Of Human Resource (Hr) Practices In Family-Owned Accomodation Smes In South Africa
Get PDFThesisThis study sought to develop and test a model for the formalisation of human resource practices among family-owned accommodation Small and Medium-sized Enterprises (SMEs) in South Africa. This is against the background of extant literature indicating that (1) the family-owned accommodation SMEs have become work intensive and their success depends heavily on the proper management of the social and technical skills of employees, (2) human resource practices in SMEs in general are reactive and informal unlike those in larger companies, and (3) the calls by policy makers to formalise SMEs to widen the government tax bracket, create employment and redress the legacy of apartheid inequalities. Such calls have not been adequately addressed by previous studies that focused on drivers of formalising HR practices among SMEs using single and limited factors in individual studies. As a result, this study takes a holistic approach through a sustained exploration of how personal and environmental factors interact with selected factors that are critical in decision making as espoused by the Unified Theory of Acceptance and Use of Technology (UTAUT) model to influence the decision to formalise HR practices by owner-managers of family-owned accommodation SMEs in the Free State Province of South Africa. The selected factors are Effort Expectancy, Performance Expectancy, and Facilitating Conditions. Basing on the UTAUT model, an explanatory structural model depicting the proposed interaction was developed. Data was collected conveniently from a sample of 206 owner-managers of family-owned accommodation SMEs in the Free State Province of South Africa. The model was then tested using Structural Equation Modelling (SEM).
The findings of the study indicate that the decision to formalise Human Resource practices in family-owned accommodation SMEs is driven by both the owner-manager’s personal characteristics and factors within the operating environment. Specific factors such as Availability of institutional support, Performance Expectancy, Effort expectancy and Facilitating conditions emerged as salient factors that drive the decision to formalise HR practices in family-owned accommodation SMEs. In turn, these factors are driven by the owner-manager’s Level of Education, SME Size and SME Location. Finally, the study contributed to the field in various ways. Theoretically, it adds on to the literature on decisions to formalise HR practices by adopting and modifying an existing model and testing it within the HR context of family-owned accommodation SMEs. Practically, the study provided insights into the drivers of the actual decision to formalise HR practices in family-owned accommodation SMEs. These drivers may be useful to HR practitioners and policy-makers in their designing of appropriate initiatives that will assist family-owned accommodation SMEs to formalise HR practices in South Africa and beyond
Comparison Of Oral And Intravenous Iron Therapy In Geophagic Botshabelo Women With Iron Deficiency Anaemia
Get PDFThesisGeophagia, the habitual consumption of soil, is associated with iron deficiency anaemia
(IDA), especially in women of childbearing age. Geophagia and IDA are very prevalent in
southern Africa. The reasons for the association of geophagia with IDA are numerous but
the one that has prominence is mineral supplementation. However, there is contradictory
in vitro evidence; with studies that support supplementation versus studies that postulate
removal of iron. If soil reduces the bioavailability of dietary iron, could it also interfere with
the treatment of IDA? The current treatment protocol of IDA is with oral iron and if oral iron
is not effective then intravenous iron therapy is undertaken. The challenge would be that
the patient would suffer symptoms of anaemia while on oral iron therapy.
This study aimed to determine if oral or intravenous iron therapy will be effective for the
treatment of IDA in non-pregnant geophagic Botshabelo females. A study comparing oral
and IV iron therapy has not been performed before. In this randomised prospective doseescalating
intervention study a group of geophagic females with IDA were recruited and
randomly assigned to two groups. Group A was expected to abstain from soil consumption
and group B continued with soil consumption. Both groups received oral iron therapy for
ten weeks. During this period, study-related procedures and blood analysis and
questionnaires, at different time intervals to assess the effects of oral therapy, were
undertaken. At the end of ten weeks, IV iron therapy was administered to those participants
who did not respond to oral therapy.
Of the 320 recruited participants only 83 met the inclusion criteria. At baseline, the general
health indicators pointed towards an otherwise healthy population group with hypertension,
obesity and IDA as exceptions. Randomisation into two groups was effective as there was
no significant difference between the two groups at baseline. There were no other confounding factors that could have resulted in the changes observed in the study
population. The absence of these confounding factors was due to non-aberrant findings in
blood loss or nutrition; absence of other medication or diseases that could interfere with
oral therapy; normal liver enzyme levels, minerals and normal general health indicators.
There were no significant red blood cell parameter changes for both short (week 4) and
intermediate (week 7) follow up periods of oral therapy for both groups. Group A showed a
statistical but clinically insignificant increase for the red blood cell parameters contrary to
group B which did not show changes. While serum iron, total iron-binding capacity and
transferrin saturation showed statistical but clinical insignificant changes for both groups.
The expected endpoint was not achieved for both groups, signifying that oral iron was not
effective in the treatment of IDA in geophagia. Soil decreased oral iron therapy
bioavailability because group B did not show significant changes. The clinical insignificant
increase in group A also implied that the absorptive surface of the gastrointestinal tract was
affected and did not recover within the ten weeks. For IV iron therapy, both groups showed
a statistical and clinically significant increase for red blood cell and iron study parameters
for both short and long term follow up study periods. Moreover, the changes for red blood
cell and iron study parameters achieved the desired endpoint for therapy. Therefore, IV iron
therapy was effective while oral iron therapy was not. These findings are contrary to other
study fields’ observation where both oral and IV iron were both effective.
It can be concluded that oral iron therapy is not effective for the treatment of IDA in
geophagia while IV iron is effective. Oral iron’s non-effectiveness indicates that the patient
will bear the symptoms of IDA while therapy is not effective. This study supports the use of
IV iron for the treatment of IDA in geophagia, thus necessitating the change of iron therapy
protocol for the benefit of geophagic IDA patients
Solid Waste Dumping And Burning Practices In The Lesotho Lowlands
Get PDFThesisPoor and inappropriate municipal waste management practices have become a universal problem and have led to adverse impacts on the environment and human health, especially in developing countries. In the lowlands of Lesotho, problems related to over population, changing consumption patterns and limited waste management services have been escalating, and these have exacerbated the impacts of inappropriate waste management methods. All activities in solid waste management involve risks that either impact workers who are directly involved or members of the community. It is for this reason that municipal solid waste management has recently been identified as a priority area for research.
This study reports on the identification and assessment of waste dumping and burning and the determination of waste management factors that cause such practices, with specific focus on the Lesotho lowlands. The impact of waste disposal sites on the environment as well as those communities living in their vicinity was accessed. This was achieved by locating sites where open dumping and burning occurred and by reviewing their status with respect to their compliance with South African waste legislation as well as international and national guidelines.
The study employed a descriptive cross-sectional design. Data were collected by using checklists when visiting the sites while two sets of questionnaires were also presented to 150 residents living in the vicinity of dumpsites or landfills and five waste management officials from five areas, namely Botha-Bothe, Hlotse, Maputsoe, Berea and Maseru. To administer the questionnaires to the residents, a direct door stepping approach was applied. The questionnaires were delivered by hand to respondents and returned to the researcher upon completion. The data were analysed using descriptive statistics and the results are presented in tables and graphs in this dissertation. The results indicate that the majority of the study population did not receive waste collection services and that most disposal sites were non-compliant with the minimum requirements for dumpsites or landfills. Waste burning was identified as a frequently used solid waste management method followed by backyard burying at residences. All five the councils (100%) under study had open dumpsites and the majority (76%; 1) of the residents mentioned that waste was burned on site, while 76.7% (84) of the residents mentioned that this was practised on a daily basis. Almost half (46.7%; 70) of the residents perceived that they were susceptible to health risks and it was revealed that gastrointestinal and respiratory diseases were prevalent at a rate of 44.1% (30) in these areas.
In light of the emergence of new waste streams due to industrialization, the establishment of comprehensive legislation that is in line with globally accepted waste disposal norms is a major requirement in Lesotho. All the official disposal dumpsites under study need to be upgraded to functional landfills and they should be properly managed. Health and safety promotion interventions and sustainable waste projects need to be introduced for the benefit of the relatively young population of Lesotho. Risk awareness also needs to be enhanced among the communities in these councils and therefore local governments should prioritise municipal solid waste management and encourage public involvement in appropriate and sustainable waste management practices
Development Of A Smart Control And Monitoring System For Impressed Current Cathodic Protection Running On Hybrid Renewable Energy
Get PDFUnderground pipelines play a significant role throughout the world as a means of
transporting potable and raw water, oil and gases over distances of various lengths; from
the source to the ultimate consumers. In South Africa, particularly in KwaZulu-Natal, these
pipelines run mostly in remote mountainous areas, to achieve shorter routes.
Due to high connection costs and low electricity consumption rate for Cathodic
Protection (CP) systems, a remote electrification through grid extension is needed, which
is a challenging solution. Furthermore, it is difficult to recover the initial investment costs,
as monthly electricity payments are made for each Transformer Rectifier Unit (TRU),
installed along the servitude pipeline.
This Dissertation discusses the use of renewable energy sources, namely, the wind and
solar, powering the Impressed Current Cathodic Protection (ICCP) systems, providing
protection against corrosion of underground pipelines used for distribution. In this study,
an off-grid hybrid wind-solar photovoltaic (PV) system is used, to supply DC current to
an ICCP system, with the aim to eliminate the need for grid power in remote CP systems,
while further optimizing the running costs. However, due to the unavailability of
continuous energy from the sun and the wind, energy storage systems are required to
ensure the continuity of power supply, hence improving the reliability of the system.
To demonstrate the technical and economic feasibility of an off-grid hybrid wind-solar
PV system, a TRU site located at Ndwedwe Reservoir 2, in Durban, is used as a case study,
as this site contains adequate wind and solar irradiance. The purpose of this study is to
investigate the technical and cost effectiveness of the proposed off-grid hybrid renewable
energy system, by making use of the renewable resources, whilst eliminating the use of grid
electricity to supply CP systems.
The sizing of the proposed system is performed using a Hybrid Optimization Model
for Electric Renewable (HOMER). The model is then simulated to evaluate the technical
performance of the system using MATLAB/Simulink. Furthermore, the baseline system is
established, which consists solely of energy supplied by the grid. The proposed system is
simulated and compared to the baseline system. The simulations showed that the system successfully meets the load demand, for various operating conditions, in a South African
case.
The prototype of the proposed system is finally carried out to test the smart control
and monitoring of the CP system, with the unit being supplied by wind and solar energy.
The obtained results reflect that the proposed system is feasible, implementable and viable.
The economic analysis is conducted for a projected period of 25 years, for both the
baseline and the proposed system. Results from the analysis indicate that the proposed
system would break-even within the first 3 years, with an approximate saving of 87%,
translating into savings of R 2 438 259.34, while giving a “true” payback period of 10 years.
This clearly demonstrates that the user could save significant energy costs if the system is
implemented.
Nonetheless, the study further showed that the use of renewable energy in the CP may be
beneficial for pipeline users in South Africa and beyond
The Impact Of Perceived Justice On Behavioural Intentions In Retail Banking: An Investigation Of Explanatory Roles Of Service Recovery And Overall Satisfaction
Get PDFArticleCustomers’ behavioural intentions following a service failure is a major concern in the retail banking sector, especially given the fact that the cost of keeping an existing customer is much less than that of acquiring a new one. Service recovery is widely used as a strategy to please a customer after a service failure and yet literature focusing on service recovery ignores the role of overall satisfaction, and in this way, provides an incomplete explanation of the long-term impact of perceived justice on customers’ behavioural intentions. The current study strives to develop and test a service recovery model that explains the relationships among perceived justice, recovery satisfaction and overall customer satisfaction; and their effects on behavioural intentions for a retail bank in a developing economy. The study also seeks to examine the mediation roles of recovery satisfaction and overall satisfaction on the relationship between justice and behavioural intentions. To test the proposed model, data collected from 210 bank customers who recently experienced problems with their bank, were analysed using the partial least squares structural equation modelling (PLS-SEM). The results suggest that the influence of justice on behavioural intentions is mediated by recovery satisfaction and overall satisfaction in series. Thus, the results reveal that the inclusion of overall satisfaction in service recovery models increases their explanatory power. Furthermore, an exploration of the mechanisms that enable justice to influence behavioural intentions stands out as one of the few empirical attempts that can bridge the theoretical gap arising from paucity of studies in this area. The theoretical and practical implications are discussed
Protection Of Microgrids Using Voltage-Based Power Differential And Sensitivity Analysis
Get PDFArticleMicrogrids are emerging as an alternative mode of operation for distribution systems integrated with Distributed
Energy Resources (DERs). With appropriate management and control of the DERs, a section of a distribution
system can operate isolated from the main grid thereby enhancing the reliability and security of supply to
consumers. However, the integration of DERs has raised many technical challenges including protection. The
traditional distribution system protection cannot provide reliable protection to the microgrid in the isolated
mode due to the limited short-circuit capacities of the converter-interfaced DERs. This paper proposes the application
of a new voltage-based relay type for the protection of microgrids. The relay algorithm achieves its
protection function through active power differential and sensitivity calculations based on voltage measurements
within a specified protection zone. In the paper, the new relay type is modelled in Digsilent PowerFactory
software and installed at the nodes of a microgrid test system. The performance of the relay type is investigated
under variety of faults. The relay is shown to operate correctly and effectively to detect and identify faults in
both radial and meshed microgrids integrated with inverter-interfaced DER technologies
3D Printed Laryngoscope For Endotracheal Intubation
Get PDFArticleThis study aims to determine whether additive manufacturing can be used to produce a safe and reliable video laryngoscope. Different designs were proposed and evaluated with a mannequin for usability. Finite element analysis (FEA) was done to estimate the stress distribution, maximum displacement at the tip, and factor of safety. A final 3D printed laryngoscope design was chosen on the basis of this evaluation. Future work on validation, whether it is safe to be used, and the limitations of the device are discussed. The device will be printed under predetermined settings and material to conform to the validation
Influence Of Large Artificial Porosity On Bending Behaviour Of Ti6Al4V Eli Additively Manufactured Specimens Subjected To Typical Loads During Mastication
Get PDFArticleEffective quality control of implants made using additive manufacturing is an important task for suppliers to comply fully with existing regulations and certifications. To study the influence of porosity on the mechanical behaviour of mandibular implants produced by additive manufacturing, preliminary tests with longitudinal flat samples were performed with 3D point bending tests. Ti6Al4V Extra Low Interstitial (ELI) specimens with artificial porosity were designed and subjected to typical loads during mastication. In this work, a finite element simulation was constructed to investigate the bending behaviour of samples, which was consistent with the experimental results. The work shows that even large artificial cavities (designed up to 0.42 mm) do not significantly affect the strength of additively manufactured 2.5 mm-thick Ti6Al4V ELI specimens under typical static loads of mandibular implants, in the considered loading conditions, and for samples subjected to appropriate surface finishing and annealing heat treatment
Promoting Continuous Professional Development Among Academics from A Vocational College by Using A Practical Workshop Based on Arduino Technology
Get PDFArticleThe internet of things has resulted in the design and development of many electronic sensors that need to be integrated with various technologies. Engineering academics need ongoing training relating to this integration as they need to subsequently teach their students. This relates to continuous professional development. The purpose of this article is to illustrate how engineering academics from a vocational college have been able to engage with the theory and practice of sensor integration with Arduino technology, thereby strengthening or reconstructing their conceptual knowledge of these electronic components. A case study is used where experts in electrical engineering designed and facilitated an academic development workshop (2 days in duration) to address a need for continuous professional development. Eighteen academics from a local vocational college attended this workshop where the first goal was to determine their conceptual knowledge of 10 electronic components using an electronic responsive system (pre-test). The second goal was to facilitate a “hands-on” laboratory session where academics had to physically integrate various sensors with an Arduino microcontroller. A post-test online questionnaire was then used to determine their conceptual knowledge again, in order to ascertain the impact of the workshop. Results indicate that their conceptual knowledge was reconstructed with regard to the purpose and use of capacitors, Zener diodes, transformers, ultrasonic sensors, reed switches and passive infrared receivers. A problematic question arose relating to photocells in the first workshop that was held in 2017, which was resolved by the facilitators prior to offering a second workshop in 2018. Positive feedback was received from the participants regarding the relevance and presentation of the workshops. The novelty of this work relates to the design of a practical workshop where all participants are engaged to either strengthen, or reconstruct, their conceptual knowledge regarding electronic components that may be integrated with Arduino technology