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A dynamical systems formulation for inhomogeneous LRS-II spacetimes
Get PDFJournal Article, Faculty of Natural and Agricultural Science, North--West University-PotchefstroomWe present a dynamical system formulation for inhomogeneous LRS-II spacetimes using the covariant 1+1+2 decomposition approach. Our approach describes the LRS-II dynamics from the point of view of a comoving observer. Promoting the covariant radial derivatives of the covariant dynamical quantities to new dynamical variables and utilizing the commutation relation between the covariant temporal and radial derivatives, we were able to construct an autonomous system of first-order ordinary differential equations along with some purely algebraic constraints. Using our dynamical system formulation we found several interesting features in the LRS-II phase space with dust, one of them being that the homogeneous solutions constitute an invariant submanifold. For the particular case of LTB, we were also able to recover the previously known result that an expanding LTB tends to Milne in the absence of a cosmological constant, providing a potential validation of our formalism
The Influence of Customer Service Management on Customers Satisfaction in Some Selected Banks
Get PDFJournal Article, Faculty of Humanities, North--West UniversityCustomer service management is a field of study that calls for continuous research in developing countries, particularly in Nigeria as a result of its significance to service delivery and customer satisfaction in the serviceoriented businesses. This study therefore examined the influence of effective customer service management in some selected banks in Ondo
State, Nigeria. Two objectives were adopted in which two alternate hypotheses were formulated to guide the study. Survey research design was adopted to collect data from a sample of 100 customers of commercial banks in Ondo state Nigeria. Results of the study indicate that customer service has significant influence on customer’s satisfaction; quality service delivery has no significant influence on customer satisfaction. The study therefore concluded that Nigerian commercial banks should continue to strategically develop and digitalize their services; introduce new and innovative products and services; maintain customer friendly relationship, and ensures quality service delivery towards enhancing customer satisfaction. It was recomm
The a priori screening of potential organic solvents using artificial neural networks
Get PDFJournal Article. School of Chemical and Minerals Engineering, Faculty of Engineering, North-West University, Potchefstroom CampusA QSPR model using artificial neural networks was constructed to estimate the binary interaction parameters for the temperature-dependant form of the NRTL model with the objective of using it as a supplement to assist limitations of group contribution methods in the screening of potential solvents for liquid-liquid extraction processes. Parameters were regressed using experimental LLE and VLE data and checked for consistency. Molecule structures were drawn and descriptors determined with the use of Materials Studio. The QSPR model uses 31 descriptors as input and produced absolute average deviations of 0.23 and 0.19 for each pair of binary interaction parameters respectively. The development of this model is shown to be effective in improving the robustness of solvent screening processes
SOCIAL WORKERS’ VIEWS ON THE IMPLEMENTATION OF LEGISLATION THAT GUIDES SERVICE DELIVERY TO CHILD-HEADED HOUSEHOLDS
Get PDFArticle, Faculty of Health Sciences (Community Psychosocial Research)--Northwest University, Potchefstroom CampusThe National Plan of Action (Department of Social Development, 2021) identified child-headed households (CHHs) as an increasing social problem in South Africa. Section 150 of the Children’s Act, 38 of 2005 (Republic of South Africa [RSA], 2005), and the Children’s Amendment Act, 41 of 2007 (RSA, 2007), consider children living in CHHs as children in need of care and protection, and give guidelines on services to these households. Currently, there is no certainty about the successful implementation of these guidelines to address the needs of this target group. This study, therefore, used a qualitative research approach with semi- structured interviews with social workers to investigate their views on applying section 137 of Children’s Amendment Act, 41 of 2007 (RSA, 2007). This study found that there were gaps to address in the social work services provided to CHHs and the implementation of the Act. Some of the main recommendations included continued training and research on the implementation of the Act
Safety properties of Escherichia coli O157 specific bacteriophages using whole genome sequencing
No full textDoctor of Philosophy in Biology, North-West University, MafikengShiga-toxin-producing Escherichia coli (STEC) strains are of major public health concern due to the severity of the illnesses they cause, especially in humans. In the food industry, the main methods of controlling contamination by foodborne pathogens often involve the application of disinfectant and detergents, which are now becoming less efficient due to the development of antimicrobial resistance. Against this backdrop, there is a growing need for the development of new strategies to combat the spread of STEC strains. Although recent studies have revealed that phage therapy has the potential to control E. coli O157:H7 in both animals and humans, there is a need to ensure the safety of the phage candidates. Thus, the aim of this study was to characterise E. coli O157-specific phages, with a focus on their safety for biocontrol purposes. A total of seven E. coli O157:H7 isolates previously isolated from cattle faeces were screened for the presence of virulence and antimicrobial resistance genes using polymerase chain reaction (PCR). The isolates were assessed for their potential to form biofilm structures under different temperatures. Furthermore, E. coli O157:H7 specific bacteriophages were isolated from wastewater using E. coli O157:H7 host. Phages isolates were characterized using transmission electron microscopy. Phage growth parameters were determined using a one-step growth curve. The adsorption rate, thermal stability, and varying pH survivability of phages were also evaluated. Whole genome sequence technique was employed to determine the genomic features, genetic similarities, and safety of E. coli O157:H7 phages. PCR confirmed the seven isolates as E. coli O157:H7. The isolates harboured virulence genes, Stx1 (7, 100%), Stx2 (3, 42.83%), eaeA (7, 100%), IpaH (3, 42.85%), and lt (7, 100%), and antibiotic resistance genes ampC (7, 100%), ParC (6, 85.7%), sul2 (7,100%), and aadA (7, 100%). The isolates were able to form biofilm at 4 °C, 28 °C, and 37 °C. Furthermore, three E. coli O157:H7 isolates were analysed using whole genome sequencing (WGS). WGS revealed that all three sequenced genomes belong to human pathogens, and they possessed several virulence and antibiotic resistance genes.
Notably, all three genomes carried the genes encoding toxins (ClyA and hlyE) and possessed varying mobile genetic elements (MGE), including six plasmid types and prophages. A cluster of regularly interspaced short palindromic repeats (CRISPR), a cas cluster, and tRNA were found in all three E. coli O157:H7 genomes. A total of 17 E. coli O157:H7 species-specific bacteriophages were successfully isolated from wastewater. Phage isolates showed varying plaque morphotype, with their sizesranging from 1.0 mm to 2.0 mm. Based on plaque morphology and clarity, eight phages were selected for further study. The spot and EOP tests (range: 0.1 to 1.0) demonstrated that phages could infect various environmental E. coli strains. Only four phages, vB_EcoM_EP32a, vB_EcoP_EP32b, vB_EcoM_EP57, and vB_EcoM_EP69, demonstrated high lytic capabilities against E. coli O157:H7 isolates and were used in further experiments. TEM analysis showed that all phages have tails and were classified under the class Caudoviricetes. The icosahedral heads measured 60 nm to 100 nm, whereas the contractile tails measured 33 nm to 125 nm. Growth parameters showed the average latent period of 15 ± 3.8 minutes, with a maximum burst size of 392 PFU/mL. The phages were discovered to be stable at three distinct temperatures (4 °C, 28 °C, and 37 °C), and were active after 15 minutes of incubation at 40 °C. All four phages except vB_EcoM_EP32a were stable at pH 3.5, 5, 7, 9, and 11, phage vB_EcoM_EP32a was not viable at pH 11.Complete genome sequencing of three lytic Escherichia phages (vB_EcoM_EP32a, vB_EcoP_EP32b, and vB_EcoM_EP57) was carried out to assess the genomic characteristics of the phages and to determine their safety. The results revealed that all three Escherichia phage genomes were composed of linear double-stranded DNA (dsDNA). The genome size of the three phages were 163,906,156,698, and 130723 bpand the GC contents were 37.61, 37, and 39% (vB_EcoM_EP32a, vB_EcoP_EP32b, and vB_EcoM_EP57 respectively). Maximum nucleotide similarity between Escherichia phage vB_EcoM_EP32a and Escherichia phage APCEc01 (NC_029091) was 96.5% while the maximum nucleotide homology between Escherichia phage vB_EcoP_EP32b and Escherichia coli O157 typing phage 6 (NC_041864) was 95.1%, and maximum nucleotide homology of Escherichia phage vB_EcoM_EP57 phage and Escherichia hage tuntematon (NC_052660) was 92.4%. Based on the genome similarities, Escherichia phage vB_EcoM_EP32a and vB_EcoP_EP32b genomes were classified under the class Caudoviricetes, Straboviridae family, and the new genus “Phapecoctavirus”, while Escherichia phage vB_EcoM_EP57 was classified under the class Caudoviricetes, Stephanstirmvirinae family. Genome analysis revealed no lysogenic (integrase), virulence, or antimicrobial resistance sequences in all three Escherichia phage genomes. This provides evidence that lytic E. coli O157:H7 phages characterised in this study are relatively stable, safe, and can infect diverse E. coli strains, implying that they can be used for the biocontrol of E. coli O157:H7 in the food industry
Budgetary Allocation and Access to Education in South Africa
Get PDFJournal Article, School of Communication, North-West University,
MafikengSince the early 1990s, South Africa has undertaken significant reforms to transform its educational system through increased budgetary allocations to enhance access to quality education. While it is well established that adequate budgetary support can improve educational access, detailed empirical studies specifically examining the effect of these allocations on educational access in South Africa are limited. This study aims to analyse the impact of budgetary allocations on education access within the country, drawing on the Keynesian proposition that government spending is crucial for promoting economic prosperity and financing educational investments. Utilising the fully modified least squares (FMOLS) method, the study finds that budgetary allocations and domestic investment have a positive and substantial impact on increasing access to education in South Africa. Conversely, per capita income was found to have a significant inverse relationship with education access in the country. Based on these findings, it is recommended that the government continue prioritising educational access, given its direct impact on human development. Additionally, enforcing compulsory schooling laws is essential to address the issue of the rising number of out-of-school children. By doing so, every citizen will have the opportunity to contribute to the country‘s sustainable growth and development
The Effect of Bismuth on the Performance of a Single-Cell Iron–Chromium Redox Flow Battery
Get PDFArticle, Faculty of Natural and Agricultural Sciences (Chemical Resource Beneficiation)--Northwest University, Potchefstroom CampusThis study examines the need for bismuth as a catalyst for the Cr 2þ/Cr3þ redox couple in an iron–chrome redox flow battery (ICRFB) using 1) open-circuit voltage (OCV) periods to understand the impact of bismuth and the mechanism of hydrogen production with and without electrolyte flow, and 2) charge/discharge cycles to evaluate how bismuth influences ICRFB performance. The OCV study finds that the capacity decay in the ICRFB cycling is not solely due to
the hydrogen evolution reaction, suggesting an alternative oxidation reaction is involved, likely catalyzed by metallic carbides like bismuth carbide. Both the OCV and the ICRFB confirm that the presence of bismuth negatively influences the battery performance due to increased H2 production. Further research is ongoing to validate the decay mechanism and confirm these results on a larger scale
Synthesis and In Vitro Antibacterial Evaluation of Mannich Base Nitrothiazole Derivatives
Get PDFJournal Article, Faculty of Health Sciences, Centre of Excellence for Pharmaceutical Sciences— Potchefstroom CampusNitrothiazole derivatives have been reported to exhibit activity against aerobic, anaerobic, and microaerophilic bacteria. This activity profile makes the nitrothiazole compound class an ideal lead source against Mycobacterium tuberculosis, which flourishes in varied environments with different oxygen concentrations. In this work, we investigated six nitrothiazole derivatives for antitubercular activity. The compounds exhibited potent activity, with compounds 9 and 10 possessing an equipotent MIC90 value of 0.24 µM. The compounds were investigated for cytotoxicity against HEK293 cells and hemolysis against red blood cells, and they demonstrated no cytotoxicity nor hemolytic effects, suggesting they possess inherent antitubercular activity.Funding
This project received financial support from the National Research Foundation (NRF) Research Grant (grant no: 137776) awarded to R.M.B. The antimicrobial and cell toxicity evaluation performed by CO-ADD (The Community for Antimicrobial Drug Discovery) was funded by the Welcome Trust (UK) and The University of Queensland (Australia)
Fibrinogen and plasma clot properties are associated with apolipoprotein B and apolipoprotein B-containing lipoproteins in Africans
Get PDFJournal Article, Faculty of Health Sciences, Centre of Excellence for Nutrition-- Potchefstroom CampusBACKGROUND: Case-control, intervention and laboratory studies have demonstrated a link between apolipoprotein B (ApoB)-containing lipoproteins and clot structure and thrombosis. There is, however, limited evidence on a population level.
OBJECTIVES: We determined the cross-sectional relationship between lipoprotein(a) [Lp(a)], low- density lipoprotein cholesterol (LDL-C), and ApoB with fibrinogen and plasma clot properties in 1462 Black South Africans, a population with higher fibrinogen and Lp(a) levels compared with individuals of European descent.
METHODS: Data were obtained from participants in the South African arm of the Prospective Ur-ban and Rural Epidemiology study. Clot properties analyzed included lag time, slope, maximum ab- sorbance, and clot lysis time (turbidity). Lp(a) was measured in nM using particle-enhanced immuno- turbidimetry. General linear models (GLM) were used to determine the associations between ApoB and ApoB-containing lipoproteins with fibrinogen and plasma clotproperties. Stepwise regression was used to determine contributors to clot properties and Lp(a) variance.
RESULTS: GLM and regression results combined, indicated fibrinogen concentration and rate of clot formation (slope) had the strongest association with Lp(a); clot density associated positively with both Lp(a) and LDL-C; time to clot formation associated negatively with ApoB; and clot lysis time (CLT) demonstrated strong positive associations with both ApoB and LDL-C, while its association with Lp(a) was fibrinogen concentration dependent.Funding
This work was supported by the North-West University, South African National Research Foundation, Population Health Research Institute, and the South African Medical Re- search Council ( SAMRC-RFA-EMU-1-0-2020 ). None of the funding bodies was involved in the design of the study, col- lection, analysis, or interpretation of the data or in writing of this manuscript. Opinions expressed and conclusions arrived at are those of the authors and are not to be attributed to the funding sources
Sloshing cold fronts in galaxy cluster Abell 2566
No full textJournal Article, Faculty of Natural and Agricultural Science, North--West University- PotchefstroomThis paper presents properties of the intracluster medium (ICM) in the environment of a cool core cluster Abell 2566 (redshift = 0.08247) based on the analysis of 20 ks Chandra X-ray data. 2D imaging analysis of the Chandra data from this cluster revealed spiral structures in the morphology of X-ray emission from within the central 109 kpc formed due to gas sloshing. This analysis also witness sharp edges in the surface brightness distribution along the south-east and north-west of the X-ray peaks at 41.6 kpc and 77.4 kpc, respectively. Spectral analysis of 0.5 – 7 keV X-ray photons along these discontinuities exhibited sharp temperature jumps from 2.3 to 3.1 keV and 1.8 to 2.8 keV, respectively, with consistency in the pressure profiles, implying their association with cold fronts due to gas sloshing of the gas. Further confirmation for such an association was provided by the deprojected broken power-law density function fit to the surface brightness distribution along these wedge shaped sectorial regions. This study also witness an offset of 4.6′′ (6.8 kpc) between the BCG and the X-ray peak, and interaction of the BCG with a sub-system in the central region, pointing towards the origin of the spiral structure due to a minor merge