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The SARAO MeerKAT 1.3 GHz Galactic Plane Survey
Get PDFArticle, Faculty of Natural and Agricultural Sciences (Centre for Space Research (CSR) )--Northwest University, Potchefstroom CampusWe present the SARAO MeerKAT Galactic Plane Survey (SMGPS), a 1.3 GHz continuum survey of almost half of the Galactic Plane (251◦ ≤l ≤ 358◦ and 2◦ ≤l ≤ 61◦ at |b| ≤ 1.◦5). SMGPS is the largest, most sensitive, and highest angular resolution 1 GHz survey of the plane yet carried out, with an angular resolution of 8 arcsec and a broad-band root-mean-square sensitivity of ∼10–20 μJy beam−1 . Here, we describe the first publicly available data release from SMGPS which comprises data cubes of frequency-resolved images over 908–1656 MHz, power-law fits to the images, and broad-band zeroth moment integrated intensity images. A thorough assessment of the data quality and guidance for future usage of the data products are given. Finally, we discuss the tremendous potential of SMGPS by showcasing highlights of the Galactic and extragalactic science that it permits. These highlights include the discovery of a new population of non-thermal radio filaments; identification of new candidate supernova remnants, pulsar wind nebulae and planetary nebulae; improved radio/mid-infrared classification of rare luminous blue variables and discovery of associated extended radio nebulae; new radio stars identified by Bayesian cross-matching techniques; the realization that many of the largest radio-quiet Wide-field Infrared Survey Explorer (WISE) H II region candidates are not true H II regions; and a large sample of previously undiscovered background H I galaxies in the Zone of Avoidance
Brain-derived neurotrophic factor, vascular alterations, and depression: The SABPA study
Get PDF, North-West University, Mahikeng CampusMotivation
Several researchers suggest that neurotrophic factors play an important role in depression. Brain-derived neurotrophic factor (BDNF) is one of the neurotrophic factors that has been investigated and it is reported that low BDNF levels occur in individuals with depression.
Brain-derived neurotrophic factor has been shown to have diverse effects on the cardiovascular (CV) system, which include angiogenesis, protective effects against oxidative stress, proinflammation and regulation of vascular tone and function. Adequate levels are therefore linked to vascular protection while low levels are associated with endothelial dysfunction and vascular remodeling. The low levels observed in individuals with depression may increase the cardiovascular disease (CVD) risk. In our study population, it has already been shown that specifically the Black population has decreased BDNF levels and increased carotid intima-media thickening when compared to their white counterparts. Many studies that originated from our study population reported significant results regarding depression. They predicted that chronic depression was associated with CV changes, such as microvasculature regulation and perfusion deficits.
Based on these prior results, we wanted to investigate whether BDNF associates with markers of vascular remodeling and function in Black individuals with and without moderate to severe symptoms of depression of the SABPA study population.
Aim and Objectives
Our aim was to investigate differences in BDNF levels as well as markers of vascular remodeling, carotid intima-media thickness (CIMT) and pulse wave velocity (PWV) in Black individuals with and without depression and whether relationships between these markers exist in each group.
Methodology
The study sample included 193 Black teachers (mean age of 44; 50% women) from the Dr Kenneth Kaunda Education district in the North West Province, South Africa. Depressive symptoms were obtained by the Patient Health Questionnaire-9 (PHQ-9). The recommended cut-off point of ≥10 indicated the presence of depression. For this study, individuals were grouped according to their depressive symptoms. The recommended PHQ-9 cut-off point of ≥10 indicated the presence of moderate-to-severe depression; a score below 10 indicated individuals without depression. A high-resolution ultrasound scan with CIMT images from at least two angles of the left and right common carotid artery was obtained by using a SonoSite Micromax ultrasound
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system. Pulse wave velocity was obtained with the carotid-dorsalis pedis PWV using Complior SP Acquisition System (Artech-Medical, Pantin, France). Serum BDNF was measured by Quantikine Colorometric Sandwich Immunoassay, with intra-assay precision between 3.8% and 4.2% and inter-assay coefficient of variation (CV) <7.6% and 11.3%.
Results and Conclusion
We observed that 44% of the population had moderate to severe depressive symptoms. The groups with and without depression characteristics were similar as no statistical differences were observed in the variables under investigation. Despite this, single regression analyses indicated an inverse relationship exist between CIMT and BDNF in individuals without depression, but not in individuals with depression (non-depressive: r=-0.214; p=0.027); depressive: r=-0.030; p=0.781). After performing multiple regression analyses adjusted for age, sex, waist circumference, glucose, CRP, LDL cholesterol, MAP and GGT an independent inverse association was confirmed between CIMT and BDNF in individuals without depression (β=-0.19; p=0.026). No significant results were observed between BDNF and PWV in both groups.
Based on our results, we rejected our hypotheses since we were unable to replicate earlier findings that suggested that depression was accompanied by lower levels of BDNF and higher measures of CIMT and PWV. Despite this, our results indicate the possibility that BDNF has a protective role in maintaining endothelial barrier integrity and promoting smooth muscle cell activity in individuals without depression. The absence of the expected results between BDNF, CIMT and PWV in individuals with depression may indicate that the interplay between BDNF and the vasculature could be compromised, although further investigation is required.Master
A simulation-based approach to illuminate inventory control decisions: policy identification and optimisation for stakeholder informed strategies
Get PDFConference proceeding, Vanderbijlpark, 2024.This paper utilises a simulation-based approach to address challenges in identifying inventory control strategies for modern manufacturing companies. It follows a systematic framework, beginning with a critical analysis of traditional inventory control methods and their inherent
complexities. By drawing from diverse research sources, it investigates the root causes of shortcomings in current inventory management practices. The study presents a dynamic simulation model designed to capture the intricate dynamics of inventory control policies.
Leveraging stakeholder engagements and input data, the simulation model functions as a virtual laboratory for testing and refining strategies. Evaluation of these strategies identifies strengths, weaknesses, and opportunities for optimisation. By integrating rigorous analysis
with stakeholder insights, the resulting strategies are theoretically robust, practically feasible, and aligned with organisational goals. The paper offers a comprehensive framework for developing informed and adaptive inventory control strategies, combining empirical research with simulation-based insights. The findings aim to advance the field of inventory management, offering actionable recommendations for optimising inventory control practices in manufacturing contexts
Towards modelling AR Sco: generalized particle dynamics and strong radiation-reaction regimes
Get PDFJournal Article, Faculty of Natural and Agricultural Sciences. Centre for Space Research (CSR)-- Potchefstroom CampusNumerical simulations of relativistic plasmas have become more feasible, popular, and crucial for various astrophysical sources with the availability of computational resources. The necessity for high-accuracy particle dynamics is especially highlighted in pulsar modelling due to the extreme associated electromagnetic fields and particle Lorentz factors. Including the radiation- reaction force in the particle dynamics adds even more complexity to the problem, but is crucial for such extreme astrophysical sources. We have also realized the need for such modelling concerning magnetic mirroring and particle injection models proposed for AR Sco, the first white dwarf pulsar. This paper demonstrates the benefits of using higher-order explicit numerical integrators with adaptive time-step methods to solve the full particle dynamics with radiation-reaction forces included. We show that for standard test scenarios, namely various combinations of uniform E- and B-fields and a static dipole B-field, the schemes we use are equivalent to and in extreme field cases outperform standard symplectic integrators in accuracy. We show that the higher-order schemes have massive computational time improvements due to the adaptive time-steps we implement, especially in non-uniform field scenarios and included radiation reaction where the particle gyro-radius rapidly changes. When balancing accuracy and computational time, we identified the adaptive Dormand–Prince eighth-order scheme to be ideal for our use cases. The schemes we use maintain accuracy and stability in describing the particle dynamics and we indicate how a charged particle enters radiation-reaction equilibrium and conforms to the analytical Aristotelian Electrodynamics expectations.We thank the anonymous referee for comments that helped us impro v e the paper’s presentation. This work is based on research supported wholly/in part by the National Research Foundation of South Africa (NRF). The Grant holder acknowledges that opinions, findings, and conclusions or recommendations expressed in any publication generated by the NRF-supported research is that of the author(s), and that the NRF accepts no liability whatsoever in this regard. LD acknowledges partial support by the NRF under award numbers PMDS22060820024 and PMDS23042496534 as well as Anu Kundu for helpful discussion. CV is funded by the research programme ‘New Insights into Astrophysical and Cosmol- ogy with Theoretical Models Confronting Observational Data’ of the National Institute for Theoretical and Computational Sciences (NITheCS) of South Africa. ZW acknowledges support by National Aeronautics and Space Administration (NASA) under award number 80GSFC21M000
Learner-centredness, partnerships and participatory action learning and research: A triad of transitioning in a special needs education context for sustainable development
No full textChapter in Book, Faculty of Education, Community-Based Educational Research (COMBER)-- Potchefstroom CampusDespite growing global awareness of and advocacy for disability rights, it is difficult to sustain meaningful transition goals for young adolescents with severe intellectual disabilities, especially regarding employment opportunities. Existing evidence from research in the field of education for sustainable development points to the benefit of involving multiple stakeholders in the transition plans of young people, in this case with severe intellectual disabilities, in order to move towards sustainable development through education. This chapter reports on research undertaken to address the question ‘How can family−school−community partnerships better meet the support needs of adolescents living with severe intellectual disabilities, before and during the transition?’ Guided by the quality-of-life theory, we provide empirical evidence from a participatory action learning and action research project that a combination of three essential features underpins a transition process that promotes development that is sustainable. We call these three features the ‘transition triad’, comprising (1) a learner-centred mindset, (2) guiding the creation of working partnerships between the school, community and parents and (3) implemented within a participatory action learning and action research framework. The study shows how collective action and continuous learning could advance sustainable development goals, particularly in the context of promoting inclusion for adolescents with disabilities through education. It is argued that a framework for the development of sustainable transition plans for learners with any level of intellectual disability holds the potential to improve the lives of not only these young people but also their family members.An ethics approval process was followed for the research study presented in this chapter. Ethical clearance (NWU-00537-19-S2) was obtained by the authors from the North-West University Education, Management and Economic Sciences, Law, Theology, Engineering and Natural Sciences focus that involves vulnerable participants and/or where there is a medium- or high-risk possibility of potential disadvantages for the participants
Beyond boundaries: A history of Gauteng's Dinokeng Game Reserve as public-private partnership and conservation initiative, 1995-2018
Get PDFDoctor of Philosophy in History, North-West University, Vanderbijlpark CampusDinokeng Big 5 Game Reserve (DGR), east of the N1 Hammanskraal off-ramp, and 43 km north of Pretoria, was established in the impoverished northeastern quadrant of Gauteng in 2011 as a provincial government, Blue IQ spatial project. By 2018, a full complement of the Big 5 animals had been re-established where they once roamed naturally. The appropriateness of this study within environmental history and boundary studies is explored. The reason for DGR’s development was to improve socio-economic conditions through employment opportunities in ecotourism and conservation. In the mid-1990s, Gauteng conservation officials envisioned a large wildlife haven in the region and had hoped to link up existing reserves and conservancies, both state and private, across Gauteng’s provincial boundary into Limpopo and Mpumalanga. Inevitably this would require discussions and negotiations over the finalisation of boundaries in a fragmented landscape. There is little alignment between the current boundaries and those originally envisaged as the current ones enclose a much smaller area than desired. The game reserve landscape architects and planners were imbued with the ideals of linking conservancies for the greater good of conservation. Therefore, they went to great lengths to persuade landowners to contribute their land to extend the reserve boundaries to the north, south, and east. They took their cue from such game reserve models as Vhembe and Atherstone, while planning to compete commercially against more distant and larger reserves such as Kruger National Park and Pilanesberg Game Reserve. The Gauteng Provincial Government planned to implement the game reserve as a public-private partnership, which is what it is today. Many obstacles arose, including from landowners, peripheral communities and, at times, a dilatory provincial government itself. Some landowners, asked to contribute their land to a trans-provincial game reserve by government conservation officials of the newly elected ANC government, were apprehensive. The prevailing zeitgeist of suspicion stemmed from uncertainty about land expropriation in South Africa, particularly as the neighbouring Zimbabwean ZANU government’s post-independence expropriation programme had quickly transmogrified into violent, opportunistic, and chaotic land grabs to which the ZANU government eventually capitulated. The DGR, its boundaries now encompassing 19 500 ha, was initially planned to incorporate a larger area of over 200 000 ha. Reasons are explored for this not being achieved. Several feasibility studies confirmed ecotourism as the most worthwhile land use for regional benefits. Despite the reserve’s diminished size, Dr P. (Trish) Hanekom, former CEO of the Cradle of Humankind World Heritage Site and Dinokeng Projects, credited “…the cooperation of communities and land owners, politicians and bureaucrats, scientists and experts, inspired planners and meticulous administrators” for its materialisation.2 It is argued here that the game reserve model, based on wildlife ecotourism, has successfully contributed to the region’s socio-economic upliftment, thanks to the establishment of a legitimate Community Trust. Evidence is provided to counter the arguably overly harsh socio-economic assessments of DGR’s success. Research revealed a history of altruistic efforts by DGR management, the corporate world, NGOs, provincial government, and private landowners to improve the economy and eco-health of communities on the periphery of DGR. The reserve’s official opening was, as argued in this thesis, the culmination of approximately 16 years of protracted, broad-based consultation between the Gauteng Provincial Government, landowners, and northeast Gauteng communities. Attention is paid to examining the changing patterns of land use in the region from the mid-19th century until the present. There is a tradition of scientific research in the region and efforts have been made to record these and to assess their global relevance. As the reserve’s boundaries depend on the addition or withdrawal of land, it is hoped that the granting of Protected Area Status, as applied for by Dinokeng Game Reserve Management in 2023, will encourage further expansion so necessary for conservation, biodiversity, and the general socio-economic health of the region.Doctor of Philosophy (Ph.D.
Ecosystem links: Anthropogenic activities, environmental variables, and macrophytes structure snail preferences in man-made waterbodies
Get PDFJournal Article, Faculty of Natural and Agricultural Sciences, Unit for Environmental Sciences and Management, Potchefstroom CampusFreshwater snails act as obligate intermediate hosts for trematode parasites that cause trematodiases threatening public and veterinary health, and biodiversity conservation. While interest in snail control for trematodiases has re-emerged, their ecology remains poorly understood. We examined the relationship between ecosystem indicators – such as environmental variables, macroinvertebrates, macrophytes, and land use – and their correlation with snail abundance, diversity, and infection prevalence in 19 man-made ponds in eastern Zimbabwe. In total, 926 freshwater snails from 10 species were collected, with 547 individuals belonging to five schistosome- competent species: Bulinus tropicus, Bulinus truncatus, Bulinus globosus, Bulinus forskalii, and Biomphalaria pfeifferi.The authors are grateful for the financial support by the Vlaamse Interuniversitaire Raad (Flemish Interuniversity Council) – Universitaire Ontwikkelingssamenwerking (VLIR-UOS) offered to AM through a Global Minds Ph.D. Fellowship (Project no. 3E210232) and the support by BRAIN-be 2.0 awarded to RS under the MicroResist project (B2/191/ P1/MicroResist). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Our thanks also go out to Reilly Travers, the manager of Imire Rhino and Wildlife Conservation for his warm welcome, consent and assistance
Timing analysis of rotating radio transients discovered with MeerKAT
Get PDFConference Contribution, Faculty of Natural and Agricultural Sciences (Centre for Space Research (CSR) )--Northwest University, Potchefstroom CampusPulsars are rapidly rotating neutron stars that emit pulses of radiation at regular intervals, typically ranging from milliseconds to seconds. The precise recording and modelling of the arrival times of pulsar emission is known as timing analysis. Rotating radio transients (RRATs) are a subclass of pulsars that emit pulses very sporadically. Because of the sparse pulse times of arrival (ToAs) typically available for these sources, they are much more difficult to time than regular pulsars, to the extent that few RRATs currently have coherent timing solutions. In this work, we present the results of timing analyses for four RRATs discovered by the MeerTRAP transient survey using MeerKAT. We incorporated additional pulse ToAsfrom each source that have been detected since their original analysis. We confirmed the known timing solution for PSR J1843−0757, with a period of P = 2.03 seconds, and a period derivative of ˙P = 4, 13 × 10−15. However, our analysis did not comport with the solution of MTP0005, which we conclude may have been mistakenly identified with the known PSR J1840−0815 in the original analysis. Finally, the spin period for MTP0007 was determined to be 1.023(1) seconds using a brute-force period fitting approach
Isolation of High Purity Phase II Biotransformation Conjugates from Urine using HPLC fractionation: A Proof of Concept
Get PDFNorth-West University, Master of Science in Biochemistry, Potchefstroom CampusBiotransformation plays an essential role in converting xenobiotics into more excretable forms. Phase II biotransformation, also known as the conjugation phase, is often overlooked. Complications in phase II biotransformation activity can lead to severe adverse health consequences and even death. One of the methods for assessing biotransformation activity is by administering probe drugs and measuring the concentrations of the drug biotransformation conjugates excreted in urine after 12 hours using HPLC-UV/Vis or HPLC-MS. To produce sensitive and selective HPLC results, analytical standards are required during method development and for quality control. Analytical standards for some phase II biotransformation conjugates are very expensive and, in some cases, unavailable for purchase, as these compounds can be difficult to synthesise. An alternative approach to synthesising analytical standards would be to isolate them from a matrix containing high concentrations of these conjugates. The urine samples at the biotransformation and oxidative stress status (BOSS) laboratory serve as a good starting material since these urine samples already contain high concentrations of biotransformation conjugates. The aim of this study was to develop a method that can be used for the isolation of high-purity phase II biotransformation conjugates. Salicyluric acid and paracetamol glucuronide were selected as the metabolites of interest, as these metabolites are the phase II biotransformation end-products of aspirin and paracetamol metabolism. Hippuric acid as selected as an additional phase II biotransformation conjugate based on the polarity of the molecule and its role in benzoic acid metabolism. Based on the literature reviewed HPLC is the gold standard method for isolating small polar compounds, such as phase II biotransformation conjugates. HPLC has the added benefit of being able to be combined with an inline fraction collector, allowing for highly efficient fraction collection. During the first part of the study, a liquid chromatography fractionation method was developed for the isolation of high-purity phase II conjugates from a standard mixture. The method was divided into 1) sample pre-treatment, 2) chromatography optimisation and fraction collection, and 3) MS optimisation. In the second phase of the study, the effectiveness of the optimised extraction, LC-UV and fraction collection methods was tested. This was achieved by employing these methods on a urine sample to isolate hippuric acid, salicyluric acid and paracetamol glucuronide.
Ethyl acetate liquid-liquid extraction proved to be most efficient and scalable for the isolation of hippuric acid, salicyluric acid and paracetamol glucuronide, with recoveries of 23.74 %, 32.17 % and 45.44 % respectively. Chromatographic separation on the Agilent XBD C18 (150 × 4.6 mm 5 μm) produced excellent chromatographic resolution that aided with easier fraction collection. Time-based fraction collection proved most effective for fraction collection, as abundance-based detection missed compounds below a specific threshold. MS source conditions and transition states were well optimised and could reliably detect hippuric acid, salicyluric acid and paracetamol glucuronide. The most abundant MRM transitions were as follows: 328.1 → 152 m/z for paracetamol glucuronide, 180.1 →105 m/z for hippuric acid, and 196.1 → 121 m/z for salicyluric acid. The optimised source conditions for these compounds were as follows: a drying gas temperature of 350°C, a drying gas flow rate of 3 L/min, a nebuliser pressure of 45 psi, and a capillary voltage of 6000 volts. Purity assessment of the primary fractions captured from urine using isocratic HPLC produced single peaks at the expected retention time for hippuric acid and salicyluric acid. The paracetamol glucuronide fraction captured was not pure after primary fractionation and required secondary fractionation. The secondary fractionation produced was a single pure peak indicating that HPLC fractionation can be employed for the isolation of high-purity phase II biotransformation conjugates
Preserving Shona and Venda culture and heritage to develop tourism post-1994: A case of the Mapungubwe Cultural Landscape, Limpopo, South Africa
Get PDFMaster of Arts in History with Heritage and Cultural Tourism, North-West University, Potchefstroom CampusThe Mapungubwe Cultural Landscape is set against the northern border of South Africa, joining Zimbabwe and Botswana, at the confluence of the Limpopo and Shashe rivers. UNESCO listed the Mapungubwe Cultural Landscape as a World Heritage Site in 2004, because the remains found at the site created an impressive cultural landscape as a heritage site of universal significance. The World Heritage Site contains a wealth of information from archaeological investigations at the K2 and Mapungubwe sites both situated in the Middle Limpopo valley that have been excavated since the 1930s. An analysis of the historical context of the Mapungubwe Cultural Landscape, specifically examining the Shona and Venda cultures, presents a unique opportunity to develop cultural heritage tourism experiences. These initiatives can contribute significantly to the preservation of cultural traditions and practices. The Mapungubwe Cultural Landscape represent a sequence of human settlement, subsistence farming, and state development between 900 and 1300 AD. An Early Iron Age settlement (during the middle of the first millennium AD) left evidence of their pottery at Mapungubwe Hill. A royal African farming community ruled over their capital K2 during the 11th and 12th centuries AD. During the 12th and 13th centuries Mapungubwe Hill became a royal African state trading with Arabia and India via East African ports along the Indian Ocean and may be seen as a watershed moment in the history of the African subcontinent. Within the so-called Zhizo archaeological sites are the remains of three capitals – Schroda; Leopard’s Kopje; and one located around Mapungubwe Hill. The remnants from these sites are a remarkable testimony to the emergence and subsequent demise of the Mapungubwe state, which was the greatest known kingdom in the African subcontinent at its peak. Mapungubwe also portrays the influence of climate change recording the kingdom’s expansion and subsequent collapse as it became vulnerable to irreversible change. Pre-colonial societies in the southern part of Africa are related to one another with specific reference to the Mapungubwe Kingdom, the Shona- and Venda-speaking people, and particularly their traditions, tangible and intangible heritage (e.g. rainmaking and burial rituals). Artefacts such as shells, pottery, ivory, glass beads, gold bangles, and the famous golden rhinoceros, recovered from Mapungubwe Hill, are proof that this kingdom's artisans were smelting gold. In the Shashe-Limpopo confluence area, 150 rock art locations have been identified, with most of the engravings being discovered at the same locations as paintings. There is strong circumstantial evidence that these rock paintings and engravings were created before around 1050 AD probably by hunter-gatherers, when the area became inhabited by the Iron Age farmers of Mapungubwe. The golden rhinoceros found in an excavated royal grave on Mapungubwe Hill is a testament to the prosperity of the polity of Mapungubwe. Both the archaeological setting and the black rhinoceroses’ ethnographically derived symbolic value among Shona and Venda speakers. This study contributes to the research on ways to create cultural heritage tourism experiences focussed on the Shona and Venda cultures. This type of tourism development could also contribute to sustainable economic growth, to secure foreign exchange derived from tourism in the Limpopo region, and specifically in the Mapungubwe National Park which is within the World Heritage Site. Cultural heritage tourism is based on the cultural resources of Mapungubwe Cultural Landscape and the preservation and presentation of Shona and Venda arts, music, and culinary traditions. This can lead advancements in heritage, creative and gastronomical tourism in this region.Master