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Neural Network-Based Vehicular Channel Estimation Performance: Effect of Noise in the Training Set
Get PDFJournal Article, Faculty of Engineering, Multilingual Speech Technologies (MUST)-- Potchefstroom CampusVehicular communication systems face significant challenges due to high mobility and rapidly changing environments, which affect the channel over which the signals travel. To address these challenges, neural network (NN)-based channel estimation methods have been suggested. These methods are primarily trained on high signal-to-noise ratio (SNR) with the assumption that training a NNin less noisy conditions can result in good generalisation. This study examines the effectiveness of training NN-based channel estimators on mixed SNR datasets compared to training solely on high SNR datasets, as seen in several related works. Estimators evaluated in this work include an architecture that uses convolutional layers and self-attention mechanisms; a method that employs temporal convolutional networks and data pilot-aided estimation; two methods that combine classical methods with multilayer perceptrons; and the current state-of-the-art model that combines Long-Short Term Memory networks with data pilot-aided and temporal averaging methods as post processing. Our results indicate that using only high SNR data for training is not always optimal, and the SNR range in the training dataset should be treated as a hyperparameter that can be adjusted for better performance. This is illustrated by the better performance of some models in low SNR conditions when trained on the mixed SNR dataset, as opposed to when trained exclusively on high SNR data.Acknowledgements
The authors are grateful to NITheCS and the Telkom CoE at NWU for their support of this researc
Occurrence, Antimicrobial Resistance, and Virulence Profiles of Salmonella Serovars Isolated from Wild Reptiles in South Africa
Get PDFJournal Article. Unit for Environmental Sciences and Management, North-West University, PotchefstroomReptiles are carriers of an array of microorganisms, including significant zoonotic bacteria of the genus Salmonella, which cause a disease referred to as salmonellosis that affects both animals and humans. This study investigated the occurrence of Salmonella serovars in wild reptiles at Timbavati Private Game Reserve in Limpopo Province, South Africa, and examined their virulence and antimicrobial resistance gene profiles. A total of 19 wild reptiles were sampled, which resulted in 30 presumptive Salmonella isolates. The isolates were identified using polymerase chain reaction (PCR) by amplifying the invA gene and were further confirmed by 16S rRNA gene sequencing. Salmonella serovars were detected in chameleons (36.8%), lizards (31.6%), snakes (15.8%), and tortoises (15.8%). The use of 16S rRNA gene sequencing revealed that Salmonella enterica subsp. enterica serovar Salamae (30%), S. enterica subsp. enterica (16.7%), S. enterica subsp. enterica serovar Typhimurium (13.3%), and S. enterica subsp. enterica serovar Indiana (13.3%) were the four most common subspecies among the investigated 30 isolates. Detected virulence genes included pagN (100%), hilA (96.7%), ssrB (96.7%), prgH (86.7%), and marT (86.7%). The isolates exhibited resistance to nalidixic acid (43.3%) and kanamycin (43.3%), followed by streptomycin (16.7%) and ciprofloxacin (3.3%). Antibiotic‐resistant genes were detected as follows: strA, strB, qnrA, qnrS, parC, aadA, aac(6′)‐Ib, and aac(6′)-Ib-cr at 33.3%, 6.7%, 16.7, 13.3%, 10%, 23.3%, 6.7%, and 10%, respectively. The findings highlight the necessity of educational initiatives aimed at reducing reptile‐related infections. Effective antibiotic treatment appears promising for infection, given the minimal drug resistance observed in reptile Salmonella serovars in the current study
“Children Are Like Vuvuzelas Always Ready to Blow”: Exploring How to Engage Young Children in Violence Research
Get PDFJournal Article. North-West University, VanderbijlparkChildren’s participation and inclusion in violence research, particularly in low- and middle-income country (LMIC) contexts, is scant and not well understood. To assess how young children can be engaged in violence research, 4- to 7-year-old children were recruited into our pilot study in a rural area of South Africa. Six interviewers, recruited from the community, were trained to complete cognitive interviews (n = 24), interviewer-administered questionnaires (n = 21), and qualitative interviews (n = 18) with young children. Three focus group discussions (FGDs) were conducted with interviewers. Findings from FGDs and assessment of interview performance highlighted that young children could feasibly and meaningfully appraise violence they experience and articulate their view in a research context. Art- and play-based approaches offered participants an easier and developmentally appropriate platform for communication, expression, and engagement, and asking directly about violence was acceptable. The ease with which children participated was determined both by their level of development and the sensitivity of the interviewers; thus, intensive training and mentorship were required over time to assist interviewers in understanding child development and mental health and increase recognition of these issues and their presentation. Interviewers critically engaged with personal values regarding children’s rights and voice in research, reflecting that some of the stories were difficult to listen to. They were able to use and value novel methods to facilitate the ethical involvement of young children to yield rich data. Without young children’s involvement and dynamic participation in violence research, the field will not have the evidence to build best practices, respond appropriately to the needs of this vulnerable population, and interrupt the intergenerational transmission of violence that develops in these formative years. Our study adds to the burgeoning evidence that young participants are vital to the research process and are valuable active contributors to understanding violence in LMICs.This study is funded by the European Research Council under the European Union’s Horizon 2020 research and innovation program (GAN/852787) and the UK Research and Innovation Global Challenges Research Fund (ES/S008101/1)
Seasonal Chemical Variation and Antidiabetic Activity of Major Compounds in Artemisia afra Infusions
Get PDFArticle, Faculty of Health Sciences (Centre of Excellence for Pharmaceutical Sciences)--Northwest University, Potchefstroom CampusArtemisia afra Jacq. ex Willd., Asteraceae, is a very popular herbal medicine in Southern Africa and is mainly used in the form of a tea infusion for the treatment of a wide variety of ailments, including diabetes. In this study, the phytochemical variation of four individual A. afra plants, collected monthly for a 1-year period, was determined. Eleven phytochemical com- pounds present in the infusions were identified and was used to illustrate the seasonal chemical variability. These compounds were also tested for their in vitro antidiabetic activity using the α-glucosidase inhibition bioassay. The results indicated that considerable phytochemical variation existed over a 1-year period within each plant but also between the four plants tested. The main bioactive compounds, namely, 1,5-dicaffeoylquinic acid and 3,5-dicaffeoylquinic acid, showed better α-glucosidase inhibition activity than the positive control, acarbose. Furthermore, these compounds appeared to show an interchangeable transition trend with its monomer, chlorogenic acid, and caffeic acid with the former seemingly increasing during summer and the latter two during the winter months. This study highlights the importance of quality control and standardisation of popular herbal remedies such as A. afra
Implementation of Coding and Robotics in South African Public Schools, Fostering Teachers’ Self-Directed Learning: A Scoping Review
Get PDFBook chaptor. North-West University, PotchefstroomThis study utilizes a scoping review of literature to explore the implementation of coding and robotics and its potential to foster and enhance teachers’ self- directed learning skills through the implementation of coding and robotics within the South African educational context. This chapter presents a comprehensive synthesis of scholarly articles, reports, and studies published from 2013 to 2023. The study further aims to provide an extensive examination of the current status quo of coding and robotics implementation, as well as the possibilities that arise for professional development as well as the development of self-directed learning skills, also identifying gaps that will guide further studies in this field and later produce a systematic literature review. This scoping review utilizes a methodical and rigorous methodology to identify the current body of literature, discern significant themes, and provide a concise summary of the results
Burnout, working alliance, and ward atmosphere: A multisite study of mental health professionals and patients with schizophrenia
Get PDFJournal Article, Faculty of Economic Management Science, North--West University-PotchefstroomThis study examined the association between burnout, psychological distress, ward atmosphere, and working alliance (WA) among mental health workers treating patients with schizophrenia spectrum disorder (SSD). Data were collected from 345 patients with SSD and 151 mental health workers across 98 residential facilities (RFs) as part of the DiAPAson project from October 2020 to October 2021. Participants were excluded from the study if they exhibited patient‐operator matching errors, dropped out, or had many missing Maslach Burnout Inventory (MBI) scores. The final sample included 282 patients and 155 healthcare workers. Burnout was assessed using the MBI. Psychological distress was evaluated with the 12‐item
version of the General Health Questionnaire. WA and ward atmosphere were evaluated with the WA Inventory and the Ward Atmosphere Scale, respectively, in both staff and patients. Sociodemographic and clinical data was also collected and analysed. Burnout was associated with a less supportive ward atmosphere, a weaker WA, and higher staff distress. Severe psychiatric symptoms evaluated with Brief Psychiatric Rating Scale in patients were also linked to staff burnout levels. Discrepancies in the perceptions of the ward atmosphere and the WA were observed between staff and patients, with patients reporting better perceptions in both domains. Our findings highlight the complex dynamics of well‐being within psychiatric
care settings, emphasizing the importance of role clarity, professional autonomy, and a positive ward atmosphere in mitigating burnout. Interventions focused on such factors may help support mental health professionals involved in SSD patient care. ISRCTN registry ID ISRCTN21141466
Urinary markers of Mycobacterium tuberculosis and dysbiosis in paediatric tuberculous meningitis cases undergoing treatment
Get PDFBackground The pathogenesis of tuberculous meningitis (TBM) involves infection by Mycobacterium tuberculosis in
the meninges and brain. However, recent studies have shown that the immune response and inflammatory processes
triggered by TBM can have significant effects on gut microbiota. Disruptions in the gut microbiome have been linked
to various systemic consequences, including altered immunity and metabolic dysregulation. Inflammation caused
by TBM, antibiotic treatment, and changes in host immunity can all influence the composition of gut microbes.
This complex relationship between TBM and the gut microbiome is of great importance in clinical settings. To gain
a deeper understanding of the intricate interactions between TBM and the gut microbiome, we report innovative
insights into the development of the disease in response to treatment. Ultimately, this could lead to improved
outcomes, management strategies and quality of life for individuals affected by TBM.
Method We used a targeted liquid chromatography–tandem mass spectrometry (LC-MS/MS) approach to
investigate metabolites associated with gut metabolism in paediatric participants by analysing the urine samples
collected from a control group (n=40), and an experimental group (n=35) with confirmed TBM, which were
subdivided into TBM stage 1 (n=8), stage 2 (n=11) and stage 3 (n=16).
Findings Our metabolomics investigation showed that, of the 78 initially selected compounds of microbiome
origin, eight unique urinary metabolites were identified: 2-methylbutyrlglycine, 3-hydroxypropionic acid,
3-methylcrotonylglycine, 4-hydroxyhippuric acid, 5-hydroxyindoleacetic acid, 5-hydroxyhexanoic acid,
isobutyrylglycine, and phenylacetylglutamine as urinary markers of dysbiosis in TBM.
Conclusion These results – which are supported by previous urinary studies of tuberculosis – highlight the
importance of gut metabolism and of identifying corre
Academic Knowledge on Quality of Life in Urban Africa: What Do We Know?
Get PDFArticle, Faculty of Natural and Agricultural Sciences (Unit for Environmental Sciences and Management)--Northwest University, Potchefstroom CampusEven though vague and contested, the construct of the quality of life can play an important role in gauging the success of spatial governance. It is present in most spatial policy objectives and many scholars describe it as the ultimate goal of spatial governance. The question remains, however, whether the construct of the quality of life is explored in sufficient depth to understand its practical relevance within widely divergent African contexts. Africa is notorious for its low levels of
life quality and many scholars argue that research on its difficulties is not focalized and conclusions are too often drawn without truly considering the unique African context. To discover the extent of the current knowledge base on African life quality, African-specific case study research was identified and analyzed. A systematic literature review was conducted following the textual narrative synthesis approach. The analysis revealed a geographically sparsely distributed knowledge base of urban African quality of life. Further to this, a wide variety of research themes were identi- fied, ranging from socio-economic, physical, and environmental characteristics to strategic planning and sustainable development. This sparsely distributed knowledge base, along with the wide variety of research themes and the undefined nature of the quality of life, makes it difficult to compare the case studies. The paper, subsequently, calls for further case study research to enable a true understanding of the association and meaning of quality of life within the African context that would ultimately support appropriate development of measurements in urban Africa
Metabolic Alterations in Mothers Living with HIV and Their HIV-Exposed, Uninfected Infants
Get PDFJournal Article, Faculty of Natural and Agricultural Sciences, Human Metabolomics-- Potchefstroom CampusHIV-exposed, uninfected (HEU) children present with suboptimal growth and a greater susceptibility to infection in early life when compared to HIV-unexposed, uninfected (HUU) children. The reasons for these findings are poorly understood. We used a metabolomics approach to investigate the metabolic differences between pregnant women living with HIV (PWLWH) and their HEU infants compared to the uninfected and unexposed controls. Untargeted metabolomic profiling was performed using 1H-NMR spectroscopy on maternal plasma at 28 weeks' gestation and infant plasma at birth, 6/10 weeks, and 6 months. PWLWH were older but, apart from a larger 28 week mid-upper-arm circumference, anthropometrically similar to the controls. At all the time points, HEU infants had a significantly reduced growth compared to HUU infants. PWLWH had lower plasma 3-hydroxybutyric acid, acetoacetic acid, and acetic acid levels. In infants at birth, threonine and myo-inositol levels were lower in the HEU group while formic acid levels were higher. At 6/10 weeks, betaine and tyrosine levels were lower in the HEU group. Finally, at six months, 3-hydroxyisobutyric acid levels were lower while glycine levels were higher in the HEU infants. The NMR analysis has provided preliminary information indicating differences between HEU and HUU infants' plasma metabolites involved in energy utilization, growth, and protection from infection.Funding
The umbrella study, of which this study forms a part, was largely funded by Collaborative Initiative for Paediatrics HIV Education and Research (CIPHER) funding from the International AIDS Society. Funding was obtained in 2017 for the protocol “Assessment of factors impacting on fetal and infant immunity and growth in HIV- and antiretroviral-exposed uninfected children” (the “Siyakhula study”); CIPHER Grant ID 2017/560-FE
Policies and measures for energy efficiency improvement at households: A bibliometric analysis
Get PDFJournal Article, Trade and Development, North-West University, Potchefstroom Campus,Recently, governmental subsidies have led to increased renewable energy adoption and household CO2 emissions reduction. However, energy efficiency improvement and greenhouse gas emission reduction potential in households’ sector are not yet fully realized. Decision-making by individuals is also a crucial factor in adopting energy-efficient and renewable energy technologies, which is why this study analyses some important behavioral change-linked issues. This study also focuses on various policies and measures to achieve energy efficiency improvements in households, such as use of renewable energy sources, renovation of residential buildings, use of energy efficient appliances etc. The methodology of the study contains a bibliometric analysis in the field of energy efficiency at households, covering the years of publication 2010-2023 and organizing all documents into 9 classifications. Among them 6 classifications have been further considered: Citation analysis; Authors’ networks; High impact journals of publishing; Knowledge mapping of co-authorship collaboration among institutions; Co-authorship among countries; Keywords concurrence analysis. Following a systematic literature review the bibliometric findings reveal the steady increase of literature production in the field of energy efficiency at households, showing also the pivotal role of institutions among developed and industrialized economies. Moreover, there is a densely and steadily growing network of keywords reported, implying the thematic expansion of this topic from the modelling-pilot scales towards the real world and in field applications. Finally, identified research constraints of energy efficiency improvement are that of: high costs, lack of information and knowledge, low priority to environmental and climate change mitigation concerns, and resistance to behavioral change