1834 research outputs found
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Communication & the role of the DA – Inter/Intra Institutional Processes: Challenges & bottle necks from a financial officer’s perspective
No full textThe Grants Management and Systems Administration (GMSA) Directorate hosted its 8th annual Research Administrators Workshop (RAW) from 9 to 11 October 2017 in the Western Cape. The workshop aimed to bring together key stakeholders from universities and science councils across South Africa, including international delegates, to share experiences and best practices in research administration and management
The influence of service quality on the post-dining behavioural intentions of customers at Cargo Hold, Ushaka Marine World
No full textThe purpose of this research study was to investigate the influence of service quality on the post-dining behavioural intentions of customers in a fine dining setting. The National Restaurant Association (2014 as cited in Ruggless 2014: 20 stated that the fine dining restaurant segment is constantly losing out on the restaurant industry market share. In order to remain competitive, restaurants need to tender service that meets the expectations of customers, as perceived service quality affects post-dining behavioural intentions (Prayag, Khoo-Lattimore and Sitruk 2015: 27).
In an attempt to devise strategies to rescue the sinking fine dining restaurant segment, this research study developed a conceptual framework model and tested its paths through path analysis, using structural equation modelling. The research study modified a DINESERV scale to obtain primary data from respondents. The modified DINESERV attained a high reliability and validity score. It was further subjected to confirmatory factor analyses and all the KMO and Bartlett’s requirements for factor analysis were satisfied.
Data was collected by means of self-administered questionnaires at Cargo Hold restaurant after agreement was reached with the management team. The convenience sampling method of data collection was applied. Diners were only given the questionnaire upon receipt of their consent to participate in this study. A total of 400 survey questionnaires were distributed. However, only 361 were deemed suitable for analysis. These 361 usable survey questionnaires represent a 90.25% response rate for this research study.
Hypotheses were tested on a hybrid of structural equation modelling path analysis and Spearman’s correlation coefficients. The results showed a positive correlation between service quality and behavioural intentions, with customer satisfaction indirectly exerting a significant effect between these constructs. The research study concludes with implications and direction for future research.National Research Foundatio
Intimate strangers: encountering the foreign in urban spaces
No full textThe year 2015 marked a significant year in South African History and it ignited a
deep desire in the hearts of locals in Port Elizabeth, Nelson Mandela Bay
Metropolitan to question and engage with the city’s ambivalent heritage landscape
and heritage discourse. The year 2015 was the year in which the country witnessed
the rise community movements that called for the removal of Victorian and
Apartheid era heritages across the country. The year also saw a rise in violent
service delivery protests and a rise in the amount of xenophobic attacks across the
county, including Port Elizabeth. In this thesis, positioned within the field of heritage
studies (Anthropology) and employing the concept of the ubuhlanti (Kraal) as a tool
to understand the former within a heritage framework. The thesis unpacks and
demonstrate how the city centre of Port Elizabeth can be likened to the concept of
the ubuhlanti. The ubuhlanti: an intimate community space, which has the potential
to double up as an exclusionary space, excluding those who do not possess the
necessary social capital to enter its centre.National Research Foundation (South Africa
Histomorphometric effects of an antiretroviral treatment and obesity on the pancreas, liver, kidney and perivascular adipose tissue in a rat model
No full textNational Research Foundatio
Design and implementation of an adaptive controller for a quadcopter.
No full textThe Solar Thermal Energy Research Group (STERG) from Stellenbosch University
is attempting to reduce the cost of Concentrated Solar Power (CSP) plants. Introducing robotics into such CSP plants can assist in reducing the
cost. An optimized calibration method currently being investigated by STERG is using a pair of quadcopters to calibrate the heliostats. The system requires
that the quadcopter has a stable hover, despite the presence of disturbances.
The aim of this project was to design and implement an advanced controller for a quadcopter. The advanced controller should improve on the existing controller
and ultimately allow for a more stable hover.
Standard control laws have unique parameters that yield a certain response based on the model on which they are implemented. Changes in the model will result in changes in the response, yielding the need for new ideal parameters. Adaptive controllers have the advantage of reducing the number of control parameters to be tuned. Reducing the number of parameters can be beneficial,
as obtaining the ideal parameters can become a time-consuming process.
Model reference adaptive control (MRAC) is the control approach that is considered in this project. This approach has previously been implemented on a quadcopter by Achtelik [Adaptive Control of a Quadcopter in the Presence of large/complete Parameter Uncertainties, (2011)]. It was desired to implement the adaptive controller on the Pixhawk flight controller.
The Pixhawk flight controller was chosen due to its capabilities when considering research projects. It also runs PX4 firmware which is part of an open source project. The designed controller should integrate well with the existing PX4 firmware to allow users still to be able to use the flight controller as before. In order to integrate the adaptive controller with the PX4
firmware some modifications to the approach followed by Achtelik et al. (2011)
was required. This report focuses on the implementation of MRAC in PX4 firmware. This required the use of quaternions in the control loop as opposed
to the common Euler angles. The mixer was also extracted from the adaptive law. The mixer refers to the part of the controller which translates moment
commands to motor commands, according to the airframe being used.
From simulations it could be seen that quaternions showed a significant improvement in reference tracking when it came to simultaneous pitch, roll and
yaw inputs. The adaptive controller was first evaluated against other controllers in simulation before testing it in practice. In practical flight, it was again evaluated against other controllers. Specifically devised tests were evaluated to test the reference tracking and disturbance rejection of the different controllers. The adaptive controller showed the largest improvement, when
compared to the other controllers, in the disturbance rejection tests. Finally, an autonomous mission was flown with the newly designed adaptive controller
and also with the original PX4 controller. This showed successful integration of the adaptive controller with the existing firmware. An improvement in reference
tracking for the adaptive controller, as opposed to the PX4 controller, was also found.National Research Foundation (South Africa
Evaluating invasion risk for freshwater fishes in South Africa
No full textBackground: South Africa, as a signatory of the Convention on Biological Diversity, has an obligation to identify, prioritise and manage invasive species and their introduction pathways. However, this requires knowledge of the introduction pathways, factors influencing establishment success, invasive potential, current distributions and ecological impacts.
Objectives: To evaluate the Fish Invasiveness Screening Kit (FISK) to predict the invasion risk posed by fish species proposed for introduction into South Africa.
Method: FISK assessments were compiled for species whose invasion status in South Africa was known. A Receiver operating characteristic (ROC) analysis was conducted to calibrate the FISK for South Africa. The calibrated FISK was used to evaluate the risk that three species recently proposed for importation for aquaculture could become invasive in South Africa.
Results: A FISK score of 14 was identified as the threshold to delineate between species that could become invasive in South Africa and those that are unlikely to become invasive. Of the three species evaluated, Silurus glanis had a high risk of becoming invasive in South Africa, Lates calcarifer was likely to be invasive and Oncorhynchus tshawytscha was unlikely to be invasive in South Africa.
Conclusion: FISK was demonstrated to be a useful risk assessment tool to evaluate the invasion risk posed by species proposed for use in aquaculture. For the large number of fish imported for the pet trade, a rapid screening assessment to flag potentially high risk species was recommended prior to a full FISK assessment for flagged species
Cryptic species and parallel genetic structuring in Lethrinid fish: Implications for conservation and management in the southwest Indian Ocean
No full textAnalysis of genetic variation can provide insights into ecological and evolutionary diversification which, for commercially harvested species, can also be relevant to the implementation of spatial management strategies and sustainability. In comparison with other marine biodiversity hot spots, there has been less genetic research on the fauna of the southwest Indian Ocean (SWIO). This is epitomized by the lack of information for lethrinid fish, which support socioeconomically important fisheries in the region. This study combines comparative phylogeographic and population genetic analyses with ecological niche modeling to investigate historical and contemporary population dynamics of two species of emperor fish (Lethrinus mahsena and Lethrinus harak) across the SWIO. Both species shared similarly shallow phylogeographic patterns and modeled historical (LGM) habitat occupancies. For both species, allele frequency and kinship analyses of microsatellite variation revealed highly significant structure with no clear geographical pattern and nonrandom genetic relatedness among individuals within samples. The genetic patterns for both species indicate recurrent processes within the region that prevent genetic mixing, at least on timescales of interest to fishery managers, and the potential roles of recruitment variability and population isolation are discussed in light of biological and environmental information. This consistency in both historical and recurrent population processes indicates that the use of model species may be valuable in management initiatives with finite resources to predict population structure, at least in cases wherein biogeographic and ecological differences between taxa are minimized. Paradoxically, mtDNA sequencing and microsatellite analysis of samples from the Seychelles revealed a potential cryptic species occurring in sympatry with, and seemingly morphologically identical to, L. mahsena. BLAST results point to the likely misidentification of species and incongruence between voucher specimens, DNA barcodes, and taxonomy within the group, which highlights the utility and necessity of genetic approaches to characterize baseline biodiversity in the region before such model‐based methods are employed
Genetic diversity of calcareous grassland plant species depends on historical landscape configuration
No full textBackground: Habitat fragmentation is considered to be a main reason for decreasing genetic diversity of plant species. However, the results of many fragmentation studies are inconsistent. This may be due to the influence of habitat conditions, having an indirect effect on genetic variation via reproduction. Consequently we took a comparative approach to analyse the impact of habitat fragmentation and habitat conditions on the genetic diversity of calcareous grassland species in this study. We selected five typical grassland species (Primula veris, Dianthus carthusianorum, Medicago falcata, Polygala comosa and Salvia pratensis) occurring in 18 fragments of calcareous grasslands in south eastern Germany. We sampled 1286 individuals in 87 populations and analysed genetic diversity using amplified fragment length polymorphisms. Additionally, we collected data concerning habitat fragmentation (historical and present landscape structure) and habitat conditions (vegetation structure, soil conditions) of the selected study sites. The whole data set was analysed using Bayesian multiple regressions.
Results: Our investigation indicated a habitat loss of nearly 80% and increasing isolation between grasslands since 1830. Bayesian analysis revealed a significant impact of the historical landscape structure, whereas habitat conditions played no important role for the present-day genetic variation of the studied plant species.
Conclusions: Our study indicates that the historical landscape structure may be more important for genetic diversity than present habitat conditions. Populations persisting in abandoned grassland fragments may contribute significantly to the species’ variability even under deteriorating habitat conditions. Therefore, these populations should be included in approaches to preserve the genetic variation of calcareous grassland species.NRF-South Afric
Legionella species persistence mechanisms in treated harvested rainwater
No full textNational Research Foundatio
