Towards a geoid consistent vertical datum in South Africa

Traditionally, vertical datums have been realised through mean sea level (MSL) data, at one or more tide gauge station(s), followed by a precise levelling procedure to establish a network of benchmarks. Most countries around the world are still using mean sea level based vertical datums, and South Africa is not an exception. However, these vertical datums suffer from a myriad of problems such as; numerous errors from the levelling networks and tide gauge sea level measurements, high cost of maintenance and upgrade, instability due to high MSL variability, inconsistency with data acquired by satellite and space-based measurement instruments and techniques, just to mention a few. Therefore there is a need to establish a geoid-based vertical datum to mitigate the limitations of mean sea level based vertical datum and to open further frontiers in geodesy, geophysics and geodynamics research, and related applications. Establishment of a national geoid-based vertical geodetic datum requires critical studies on the existing national height system(s) and related distortions, appropriate height system and related reference surface, offset between a local height datum and the intended reference surface, among others. The world is moving towards global unification of vertical datums to modernise the vertical positioning technique, an international height reference system (IHRS) would provide a globally unified height reference system. The horizontal positioning is already realised on the international terrestrial reference frame (ITRF) with high precision, and a similar approach for the realisation of a new vertical datum for South Africa is required. This study carries out analysis on the following aspects over South Africa: comparison between spheroidal, orthometric and normal height systems; accuracy of levelling network; vertical datum offset in relation to geoid, quasigeoid and the IHRS. It concludes by providing a unique framework for establishing a geoid-based vertical datum in South Africa. A numerical investigation of the correlation between the South African spheroidal, orthometric and normal height systems is conducted. It is determined that the spheroidal orthometric height system is more correlated with the normal height system (~ 21.3 cm on average) than the orthometric height system (~ 40.7 cm on average). A further numerical assessment was conducted to determine the magnitude of misclosures and the empirical value for the first order levelling network on the levelling loops. It was determined that majority of the levelling loops fall within the acceptable empirical value for the first order levelling network (c = 0.003). However, only one levelling loop does not fall within the acceptable range of misclosure for the first order levelling network, with a misclosure from spirit levelling measurement of −10.2 cm while the estimated acceptable misclosure is 9.7 cm. The vertical datum offset between the South African local vertical datum and global vertical datum was achieved by estimating the vertical datum offset and the geopotential values on the four fundamental benchmarks. A single-point-based geodetic boundary value problem (GBVP) approach was used following Molodensky's theory for estimating the height anomalies from the disturbing potential using Bruns's formula. The gravity potential at each tide gauge benchmark (TGBM) in South Africa deviates from the potential of the global reference surface by 0.585, −2.023, −2.597 and 2.105 m!s"! for Cape Town, Port Elizabeth, East London and Durban tide gauge benchmarks, respectively. The corresponding vertical datum offset between the international height reference system and the four fundamental benchmarks over South Africa are 5.973, −20.647, −26.518 , and 21.496 cm for Cape Town, Port Elizabeth, East London and Durban tide gauge benchmarks, respectively. The datum offsets between the land levelling datum (LLD) and the global vertical datum has been estimated, for the first time over South Africa, in this study. A preliminary geoid-based vertical datum in relation to the IHRS for South Africa was determined and evaluated using 138 GPS/levelling data points distributed over the country. However, since it would be difficult to identify exactly which data points are associated with a particular TGBM, the TGBM in Cape Town was held fixed for this analysis. During this analysis, the spheroidal orthometric height was unified to the IHRS (5#%&# and the local quasigeoid is estimated to be approximately 15.8 cm on average. An adequate data coverage is required to improve the quality of the determined vertical datum offset for the South African vertical datum in relation to the global vertical datum. It is proposed in this study that a normal height system should be adopted for South Africa, with the relevant reference surface being quasigeoid model. Some considerations to be taken during the implementation and adoption of a consistent geoid-based vertical datum in South Africa are discussed

Critical competencies of successful business rescue practitioners in South Africa

The success rate of business rescue in South Africa remains low and the intention of the Department of Trade and Industry to save jobs is not being achieved. Business rescue is a growing area of business focus in South Africa due to an increase in the number of companies filing for business rescue. There is a need for empirical research on factors that influence the success of business rescue. This study explores the foundational competencies of successful business rescue practitioners in South Africa and the required domain knowledge to supports these competencies. The study was a qualitative, exploratory study that gathered data through 15 detailed, semi-structured interviews with business rescue practitioners, academics, legal experts, banking professionals and turnaround experts. Literature revealed four higher-order competencies for business rescue practitioners, namely sense making, decision making, integration and collaboration. The study confirmed these higher-order competencies and expanded to the foundational competencies that are crucial for these higher-order competencies. The research also confirmed that business management, legal knowledge and finance domain knowledge are the required domain knowledge areas that support business rescue competencies. A key finding that further emanated from this study is the need for a turnaround mindset and upholding high ethical standards amongst business rescue practitioners in South Africa. The findings of this study were integrated into a Business Rescue Practitioner Competencies Model that may aid managers in selecting and evaluating business rescue practitioners, it may guide accreditation bodies and learning institutions in developing training material for business rescue practitioners and assist business rescue practitioners to enhance their competencies.Mini Dissertation (MBA)--University of Pretoria, 2019.tk2020Gordon Institute of Business Science (GIBS)MB

Engineering Innovative Ways To Sustain Learning For Pre-Service Economic And Management Science Teachers In Curriculum Practice

Remote learning is the future of teaching and learning. The inception of Covid 19 has disrupted the traditional face to face teaching and learning and raised a need for scholars to investigate innovative ways to adapt to global disruption. Remote learning was the preferred option as it is effective and efficient to sustain learning even post the disruptions. In recent years, extensive research has been conducted on how to use the industrial revolution in curriculum reform. Remote learning is one of the recent initiatives in the curriculum and pedagogy reform package in South Africa that involves the use of remote learning to improve teaching and learning. This article investigates innovative ways to engineer a shift to remote learning for pre-service economic and management science teachers and the use of remote learning curriculum practice to achieve pedagogy mastery. The aim of the article is to answer the research question: what innovative ideas can be generated to engineer shift to remote learning in curriculum practice. Architecture theory is used as the main lens for the study. Connectivism learning approach as a form of education science is used to generate data in this study. Connectivism is immersed in the narrative that knowledge is distributed across networks through connections and connectivity, and learning is guided by connections and connectedness. Based on technology, connectivism is a learning approach that emphasizes knowledge acquisition focused on the future, rather than the past. Connectivism is relevant to this study because it encourages and changes the essential nature of building knowledge. Connectivism empowers teacher educators as well as preservice students through using collaboration in learning. Critical discourse analysis was used to arrive at the following broad findings: Pre-service economic and management science teachers should participate in diverse learning spaces indicated by the varying standards of learning embodied in the existing context of the South African society embracing educational inequalities. Implementation of the three c`s of remote learning: connectivity, content and capacity will enhance possibilities for economic and management sciences pre-service teachers to use remote learning in their practice of the curriculum. The paper concludes with expected recommendations that the prefigured remote learning for professional teaching practices be reconfigured

Work design, anxiety and depression: A call centre case study

This research study explores the possible relationships that may exist between the work design, level of anxiety and depression in South African call centres. By investigating the work design of a call centre and exploring its relationship to anxiety and depression will help to achieve this. Variables that will be looked at in this research study are work design, anxiety and depression. Our sample comprised of call centre agents. The agents were came from one inbound and one outbound call centre. It was then realized during the analysis of the data that there is no significant difference between the two call centres therefore the two samples were merged into one sample thus increasing our sample size to a total of 56 respondents. Pearson correlation analysis revealed that significant positive correlations exist between all the variables, work design, level of anxiety and depression. It was also proven that the higher the JCI score the lower the anxiety and depression levels. Additional correlation tests were conducted to see whether there is a relationship that exists between JCI subscales, anxiety and depression. Results showed that not all of the sub-scales of the JCI show a significant correlation with Anxiety and Depression. Only Autonomy and Feedback to some degree correlate with Anxiety (r = 0.38; p = 0.004 and r = 0.26; p = 0.053). Variety and Authority correlated significantly and positively with Depression (r=0.38; p = 0.004; and r = 0.32; p = 0.017). These results indicate good support for this research study, illustrating that the manner in which work is designed will have an effect in the anxiety and depression levels experienced by the employees

Database Design

Exam paper for first semester: Database Desig

Development of a real-time PCR assay to detect the fusion gene of the D26 strain of a commercial avian avulavirus 1

Newcastle disease (ND), caused by avian avulavirus 1 (AA1), an enveloped, negative sense, single stranded RNA virus belonging to the Paramyxoviridae family. ND is found world-wide and leads to severe economic losses from mortality and condemnation of carcasses. Virulent ND causes clinical signs such as respiratory distress, central nervous signs, drop in egg production, weakness, gastro-intestinal symptoms and death. The disease is listed by the World Organisation for Animal Health (OIE) and outbreaks require reporting to the OIE. The OIE requires a definitive diagnosis of virulent AA1 to enable effective control of an outbreak by strict control measures and trade restrictions. Currently the real-time reverse transcription polymerase chain reaction (RRT-PCR) assay used to diagnose ND does not differentiate between field and vaccine strain. The aim of this study was to develop and optimise a real time RT-PCR assay that detects chickens vaccinated with Vectormune® HVT NDV vaccine based on the F gene of the D26 strain. NDV F gene sequences were downloaded from Genbank® and aligned. A region unique to the D26 strain, between nucleotides 69 to 131 (using accession number M24692 for numbering) was identified and a TaqMan® MGB™ assay was developed. Primer and probe concentrations were optimised at 200 nM. Nucleic acid was purified using a MagMax™ Pathogen RNA/DNA extraction kit and a MagMax™ Express Magnetic Particle Processor (ThermoFisher Scientific). TaqMan Fast Advanced Master Mix PCR reagents were used to amplify the AA1 F gene with one StepOnePlus Real-time PCR system. The PCR efficiency was calculated to be 81.8% with 0.9942 coefficient correlation (R2). The 95% limit of detection was 10-1.31 plaque forming units per reaction. The assay was specific and did not detect any other AA1 isolates tested. Twenty-four spleen impression smear field samples from chickens (12 Vectormune® HVT NDV vaccine samples and 12 vaccinated with ND virus conventional vaccine) preserved on Whatman® FTA cards, were collected between day 21 and 28 post vaccination. The assay detected only the D26 vaccine strain and was negative when tested on other field samples. The developed real time PCR was sensitive, reliable and repeatable and will also be able to produce results rapidly as compared to other conventional methods.Dissertation (MSc)--University of Pretoria, 2018.Veterinary Tropical DiseasesMScUnrestricte

A Pathway To Adapt Hybrid Learning For Pre-Service Teachers As The New Normal In Curriculum Practice: Using Whatsapp As A Learning Tool

The use of hybrid learning in curriculum practices to improve teaching and learning a recent initiatives in the package pedagogical reforms in South Africa. Nowadays, an increasing number of students have their own smartphones, and WhatsApp is becoming popular in terms of mobile learning and communication .WhatsApp is an application that can be used by students in post-secondary education to improve performance, and motivation to prepare for their learning . This article reflects on a pathway followed by pre-service economic and management sciences (EMS) teachers in their ability to adapt and sustain their learning through WhatsApp as a hybrid learning tool. The study is underpinned by connectivism theory. Qualitative research using Participatory Action Learning and Action Research (PALAR) approach as a form of critical education science is employed in research methodology and design . Semi structured Interviews were conducted with 30 Pre-Service EMS teachers to generate data. PALAR is relevant to the study as it pilgrimages three principles of responsible research innovations such as recognition of participants, establishing professional learning communities and critical reflections embracing diversity characterised in unequal education context in the South Africa. Critical discourse analysis was used to arrive at the finding that depicts close 96% of the participants are inclined to use WhatsApp as a learning tool as 84% had reliable access to Wi-Fi on campus. The paper concludes with recommendations that the hybrid learning is the future of teaching and learning in post Covid era and should be embraced

A comparison of the least squares collocation and the fast Fourier transform methods for gravimetric geoid determination

The objective of the research was to study the performance of the least squares collocation (LSC) and the fast Fourier transform (FFT) techniques for gravimetric geoid computation. The Land Levelling Datum (LLD) is the South African vertical datum based on more than 100 years old tide gauge measurements of mean sea level (MSL). The LLD is poorly defined so an alternative is required. The SAGEOID10 (Merry, 2009) hybrid geoid model was computed for the purpose of replacing the existing vertical datum. Two gravimetric geoid models were computed using different techniques for evaluation of the Stokes' integral, such as, LSC and one dimensional fast Fourier transform (1D-FFT) technique. The long wavelength component of the geoid models were computed using the EGM2008 geopotential model truncated at degree 720. The use of fast spectral techniques is required due to an increase of both quality and type of data available for geoid determination. The FFT method is most reliable than the LSC method, since it requires less computational time on large data set than the LSC. A system of linear equations of order equal to the number of data points is generated on the LSC method. The geoid model was computed over the province of Gauteng. It was then compared to the SAGEOID10 hybrid geoid model. The computed geoid models, SiPLSC and SiPFFT geoid model compared to the SAGEOID10 model with standard deviation of 5.6cm. The long wavelength component of the computed geoid model compared to the EGM2008 geopotential geoid model with a standard deviation of 4.2cm

Pre-Service Teachers’ Academic Identity and their Lived Experiences in Remote Learning: The New Normal in Curriculum Practice

Research ArticleThe Ministry of Tertiary Institutions of South Africa charged post-secondary institutions to implement measures to achieve the government's social distancing policy. Institutions shifted to remote learning to sustain their core business of teaching and learning. However, there were concerns with the implementation of these measures. For instance, pre-service teachers were seen as ill-equipped and poorly supported during remote learning. This paper aims to contextualise the identity of pre-service economic and management science teachers and reflect on their experiences of curriculum practice during remote learning. Architecture theory was used as the main lens for this study. Furthermore, the goal is to reflect on their adaptation to remote learning as the new normal. Participants’ experiences and factors that affected them are discussed as data collected using the critical participatory action learning and action research (CPALAR) approach as a form of critical education science. Critical discourse analysis was used to arrive at the following broad findings: firstly, higher learning institutions are obligated to create practical learning experiences for pre-service teachers. Secondly, participants were directly affected academically, socially, and psychologically. This paper concludes with the recommendation that hybrid learning as the new normal is the future of teaching and learning and should be embraced

Reflections By Pre-Service Economic And Management Sciences Teachers On Their Experiences Of Remote Learning In Curriculum Practice

Research ArticleCurriculum reformists were caught off-guard over the past two years by the unforeseen and extreme pressure of the COVID-19 pandemic. This phenomenon threatened to engulf humans in despair. Institutions of higher learning initiated moves to remote learning, as a measure to prevent the spread of the virus while continuing to promote teaching and learning. Scholars were absorbed by grasping the importance and application of a revolution in curriculum reform. The use of remote learning in curriculum practice to improve teaching and learning is a recent initiative in the package of curriculum and pedagogical reforms in South Africa. The aim of this paper is to reflect on adaptive experiences of pre-service economic and management sciences teachers, their ability to adapt curriculum practice to remote learning of this specific curriculum, and pedagogical reform of the use of remote learning in schools. An architecture theory, which draws on the famous quotation of Adolf Loos's parable about “the poor rich man” and whether they really understand the lesson, was used as the main lens for the study. An interpretative phenomenological analysis approach, as a form of critical education science, was employed to generate data. The basic purpose and essence of the IPA approach in a qualitative research study is to examine the life experiences of the research participants and to allow them to narrate the research findings through their lived experiences and critical reflections, thereby deliberately embracing diversity as characterised by the unequal context of South African education. Phenomenological analysis was used to arrive at the following findings. First, higher learning institutions are obligated to create practical learning experiences for pre-service teachers. Second, the phenomenon that resulted in the necessity to embrace remote learning impacted participants academically, socially and psychologically. The paper concludes with the recommendation that the prefigured remote learning for professional teaching practice should be reconfigured