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The search for pulsed radio and gamma-ray emission from the cataclysmic variable system AE Aquarii using MeerKAT and Fermi-LAT data
No full textThe nova-like AE Aquarii was extensively studied using 11 years of data and contemporaneous optical data with the aim to establish pulsed gamma-ray emission at the rotational period (33.08 s) of the white dwarf and the first harmonic (16.54 s). In addition the study was also aimed at identifying pulsed radio emissions at or near the fundamental frequency. Therefore the search of pulsed radio and gammaray emission using MeerKAT (radio) data and upgraded Fermi-LAT pass 8 (gammaray) datasets is presented.
The L-band 45 mins observation of AE Aquarii resulted in the first detection of this source by the MeerKAT telescope. Also, the pulsed radio emission search resulted in the first detection of pulsed emission modulated at the white dwarf’s rotational period (33.08 s). Further investigation resulted in no indication of any pulsations at the first harmonic (16.54 s). The pulsed signal’s overall strength is confined to lower L-band frequencies at the onset of the flare event. No pulsations were significant at the peak of the flare-like event. The spectral variation investigations revealed an optically thin spectrum. This optically thin spectrum observed in the MeerKAT data appears to be uncorrelated to the overall radio spectrum up to 1000 GHz. Hence, a correlation between the MeerKAT data and observations at higher frequencies could
be an exciting topic for in-depth follow-up studies. Investigation for gamma-ray emission from AE Aquarii was conducted using an 11-year baseline of the archived upgraded Fermi-LAT pass 8 dataset. The standard binned and unbinned analyses techniques resulted in no detection of any significant gamma-ray excess in the region of AE Aquarii. However, the search for transient burst-like gamma-ray emission through a light curve revealed sections of the data with an excess significance of 2 s. A search for pulsed gamma-ray emission from these sections resulted in substantial evidence of pulsed signal from some of these sections with excess significance. An additional search for pulsed gamma-ray emission using shorter time bins resulted in detecting more significant pulsations at both the fundamental (33.08 s) and the first harmonic (16.54 s) frequencies. The stacked periodogram displayed clear evidence of particle acceleration from two polar zones of the white dwarf in AE Aquarii, which resulted in a double pulse. Periods contemporaneous to observed optical flares displayed weak pulsations in the noise level. After stacking the periodograms, a significance of over 4 s is seen at the fundamental frequency (33.08 s). A further search for evidence of sporadic burst-like gamma-ray emission from AE Aquarii using refined or more selective filtered data resulted in the detection of AE Aquarii with a significance of 14 s from both the binned and unbinned analyses techniques. The gamma-rays detected from a more constrained refined filtered dataset show clear gamma-ray spectral hardening above the galactic gamma-ray emission. These results have significant implications for follow-up studies of AE Aquarii using ground-based Cherenkov telescopes.National Research Foundation (NRF
Climate change impacts on temperature and chill unit trends for apple (malus domestic) production in Ceres, South Africa
No full textClimate is an essential part of crop production, determining the suitability of a given region for deciduous fruit products such as apples (Malus domestica). It influences the yield and quality of fruits. There is strong evidence of global and regional-scale climate change since the advent of the industrial era. In South Africa, mean surface temperatures have revealed a warming trend over the last century. This study aimed to assess the impact of climate change on temperature and chill unit trends for apple production in Ceres, South Africa. The daily positive Utah chill units (DPCU) model was used as frequent high temperatures can lead to a high negation volume. Historically observed (1981–2010) and future projected (2011–2100) temperatures were obtained from the South African Weather Service (SAWS) and three ensemble members of the Cubic-Conformal Atmospheric Model (CCAM), respectively. The latter employed the RCP8.5 pathway. Linear trends were calculated for temperature and accumulated PCUs for the historical base period. The probability of accumulating specific threshold PCU values for both historical and future periods was assessed from cumulative distribution functions (CDFs). The historical change in minimum temperatures showed no significant trend. Ceres revealed a warming trend in maximum temperatures over the historical period. By the 2080s, the probability of not exceeding a threshold of 1600 PCUs was exceptionally high for all ensemble members. Future projections showed a decline in the accumulated PCUs of 2–5% by the 2020s, 7–17% by the 2050s, and 20–34% towards the end of the 20th century. Based on these results, it is clear that winter chill units are negatively influenced by climate change. The loss in yield and fruit quality of apples due to climate change can negatively impact the export market, leading to significant economic losses for apple production in the Ceres area.Publisher's versio
The repurposing of acetylsalicylic acid as a photosensitiser to inactivate the growth of cryptococcal cells
No full textPhotodynamic treatment (PDT) is often successful when used against aerobic microbes, given their natural susceptibility to oxidative damage. To this end, the current study aimed to explore the photodynamic action of acetylsalicylic acid (ASA; aspirin, which is commonly used to treat non-infectious ailments), when administered to respiring cryptococcal cells. The treatment of cryptococcal cells, i.e., exposure to 0.5 or 1 mM of ASA in the presence of ultraviolet light (UVL) for 10 min, resulted in a significant (p < 0.05) reduction in the growth of tested cells when compared to non-treated (non-Rx) cells, i.e., no ASA and no UVL. The treated cells were also characterised by diseased mitochondria, which is crucial for the survival of respiring cells, as observed by a significant (p < 0.05) loss of mitochondrial membrane potential (DYM) and significant (p < 0.05) accumulation of reactive oxygen species (ROS) when compared to non-Rx cells. Moreover, the photolytic products of acetylsalicylic acid altered the ultrastructural appearance of treated cells as well as limited the expression levels of the capsular-associated gene, CAP64, when compared to non-Rx cells. The results of the study highlight the potential use of ASA as a photosensitiser that is effective for controlling
the growth of cryptococcal cells. Potentially, this treatment can also be used as an adjuvant, to complement and support the usage of current anti-microbial agents.Publisher's versio
Attention-Deficit/Hyperactivity Disorder (ADHD) symptom severity and gut microbiome dysbiosis: an aetiological perspective on an emerging relationship
No full textAttention deficit/hyperactivity disorder (ADHD) is the most prevalent neurodevelopmental disorder in the world with a range of adverse outcomes. Collaboration between researchers, healthcare practitioners and families to enhance preventative- and treatment strategies informed by aetiological conceptualisations is key to its management. ADHD presents a complex clinical picture. Genetic heredity and known environmental risk factors do not account for the full spectrum of presenting cases, and many children do not respond to psychopharmaceutical treatments. The role of the gut microbiome in psychiatric disorders has been receiving exponential research interest, radically reconfiguring conceptualisations of mental health. Gut microbiome research beyond microbial analyses is in its infancy, especially with children diagnosed with ADHD. This study is the first focused specifically on the overlapping aetiological factors involved through a clinical psychological lens. A quantitative dominant mixed methods research (MMR) approach was the most appropriate to address this complex, multifaceted research inquiry comprehensively. Consequently, a total of 197 research participants were selected on the basis of being the biological parent of a child between the age of 6 and 12 who has been formally diagnosed with ADHD in South Africa. Each participant completed the following online surveys: the ADHD Rating Scale-IV, the 6-Item Gastrointestinal Severity (GIS) Index and a self-compiled biographical questionnaire. The relationship between symptoms of gut dysbiosis and ADHD symptom severity was explored from a quantitative perspective. A statistically significant correlation was found between GIS Index total score and ADHD Inattention subscale (p = 0.026). Four independent variables were found to make significant contributions (i.e., maternal prenatal smoking, mode of delivery, breastfeeding, and maternal prenatal obesity), although no substantial mediating role by GIS Index symptoms were found. The qualitative results elicited parents’ observations of the influence of specific factors (e.g., gastrointestinal symptoms, diet, probiotic supplements, worm/parasite treatment) on ADHD symptoms. General concerns regarding children’s gut health and the adverse side-effects experienced from psychopharmaceutical treatments were also elicited. This study provides future researchers with a general overview of the overlap between the risk/protective factors involved in ADHD and gut dysbiosis, whilst elucidating the various bidirectional pathways involved in the intricate, emerging relationship between the gut microbiome and mental health
Adaptation, coping strategies and resilience of agricultural drought in South Africa: implication for the sustainability of livestock sector
No full textAgricultural drought has put sub-Saharan African under significant pressure, and without adaptation, will
negatively influence a future generation. Hence, it is crucial to assess the adaptation and coping strategies, the resilience of agricultural drought, its implication on the sustainability of the livestock sector, and developing future interventions. Data of 217 smallholder livestock farmers were used in a principal component analysis to estimate the agricultural drought resilience index as an outcome variable against social wellbeing, economic outcome, environmental variable and adaptive capacity variables. The results found that 21% of the livestock farming households sold their livestock as an adaptation and coping strategy. In contrast, 20% of the farming households used alternative land use as an adaptation, and coping strategy, 20% stored food, 17% asked for animal feed, 6% sought employment, 6% migrated, 5% kept drought-tolerant breeds, 3% received relief grants, 2% used their savings and investments, and 1% leased their farms. When natural, economic and social sustainability was viewed as a resilience process, the three pillars positively and significantly impacted households' agricultural drought resilience. This implied that the more smallholder farmers participated in social networks and cooperatives, the higher the resilience to agricultural drought. Further, the more resources, income, access to land, access to water, access to credit, and additional types of farming, the higher the households’ resilience to agricultural drought and adaptive capacity. Thus, the three pillars of sustainability are crucial for enhancing the resilience and adaptability of smallholder livestock farmers. The study recommends that government aid reduce vulnerability to agricultural drought via access to agricultural credit and encourage farmers to be part of social networks and cooperatives. Additionally, the government could improve access to land and water rights to boost
the resilience of smallholder farmers to agricultural drought. This could be achieved through collaboration and coordination among all role players.Publisher's versio
Diagnostic accuracy and reliability of smartphone captured radiologic images communicated via WhatsApp®
No full textBackground: Sending radiographic images as instant messages have become a common means of communication between physicians, aiding in triaging and transfer decision-making in emergencies. While the use of technology is increasing, this is not the case for the underserved or rural areas of South Africa with no picture archiving and communications system (PACS) or advanced hardware in place. In these areas, however, the medical population tends to have nearly universal access to smartphones and would benefit from the ability to share images quickly and easily with trained radiologists. South African data on diagnostic reliability of smartphone radiology images is lacking. Objectives: The objective of the study was to determine the accuracy and reliability of diagnoses made on radiologic images with a smartphone compared to radiologic images on PACS. Method: This was a cross-sectional study. Radiographs from 1 June 2018 to 1 July 2019 were selected from the PACS system at a tertiary hospital in the east-central South Africa. The images were displayed on a PACS computer screen and captured by the researcher using a smartphone. Five radiology registrars received the images via WhatsApp® and reviewed them on their phones. After three weeks, the registrars viewed the images in random order on a PACS station. McNemar’s test was used to compare the diagnostic accuracy of smartphone and PACS. Kappa values were calculated for agreement. Reliability was assessed by analyzing the results of different registrars and diagnoses separately. Results: One hundred and thirty-five X-rays, representative of common emergency conditions, were selected. For all registrars, the PACS accuracy was generally higher than the smartphone accuracy. The Kappa values all indicated fair to moderate agreement between smartphone and PACS diagnosis. Conclusion: Capturing radiographic images using at least a 12-megapixel smartphone and sharing them via WhatsApp® is a reliable method that can be used with a high degree of confidence in emergencies to aid clinical decision making. This method of viewing medical imaging is however not a substitution for images viewed on PACS
Plans and interventions of South African Grade 1 educators during the 2020 lockdown period
No full textThe extended lockdown in 2020 found South African educators employing innovative strategies to teach and assess Foundation Phase learners. Educators had to make do with reduced hours in the classroom and experienced new challenges in delivering curriculum content to learners that had barely grown accustomed to the formal classroom setup. Empirical research attempted to identify the plans and approaches used by grade 1 educators. The findings may indicate best practices as experienced in this time and help to inform the approach taken during future repetitions of extraordinary circumstances. A theoretical and conceptual framework based on the current constructivist approach adopted by the Curriculum Assessment and Policy Statement (CAPS) guided the empirical research and informed the construction of the questionnaire. The key findings were themed into strategies for presenting teaching and learning, communication, and the impact on schooling. Findings were compared to the premises of the theoretical framework and conclusions drawn. It was noted that educators were hesitant to move their schooling entirely to the virtual learning platform and eager to return to the school environment. Various obstacles posed by the digital divide were flagged as threats to future situations and the involvement of parents was emphasized. The resilience of educators to continue to ply their trade, and their belief in the indomitable spirit of children, may offer conducive circumstances for future innovations in education.Publisher's versio
The role of the Catholic Church in poverty alleviation: the case of Kopanong Municipality, Free State
No full textDissertation (MDS (Development Studies))--University of the Free State, 2021The Catholic Church throughout the world has a long and eventful history in poverty alleviation, through works of charity and development in fulfilment of its mission of advocacy and adherence to the Catholic Social Teaching option for the poor. Kopanong Local Municipality is one of the rural municipalities in South Africa in which a number of poverty alleviation strategies have been implemented. Despite these strategies, however, poverty seems to be on the rise. This study’s aim was to further understand the role of the Catholic Church in poverty alleviation in Kopanong Local Municipality in the Free State. Through a review of literature, interviews and focus group discussions, the study was able to find that the Catholic Church, through its strategies and programmes such as Rural Development Support programmes, the Rural Education Access Programme, and other charitable works, has to some extent managed to help the poor. However, it is through a better understanding of poverty and poverty alleviation, and through the implementation of social justice programmes and the improvement of social development programmes, that the Catholic Church could effectively improve livelihoods
Managing the culture of COVID-19 "New Normal" as a motivation for university students in South Africa
No full textThe advent of COVID-19 and its implication on university education has been the bone of contention in recent times. The COVID-19 emergency has led to a change in knowledge inputs, processes, and outputs. This trajectory has demotivated student approaches to their learning. In response to this revolution, this study provides motivational strategies through students' perspectives to respond to the underside of new normal among South African university students. Ubuntu underpins the study within the Transformative Paradigm lens and Participatory Research as a research design. Ten students of a particular module in a selected university in South Africa were chosen to participate in the study. They were selected using the snowballing sampling technique because the participants were under level 3 lockdown with little or no access to campus at the time of the study. Online interview via phone calls, email and WhatsApp, was conducted with the students, and the data were analysed using Thematic Analysis. The study revealed a lack of visualised physical engagement between students and their lecturers and unstable internet access and lack of the internet as the major challenges. The study, therefore, recommends solutions that there should be adequate provision of effective online audio-visual sessions with enough space for student-lecturer’s interactions and low-tech online sessions and content deliveries.Publisher's versio
Use of diagnostic techniques by private practising optometrists in South Africa
No full textIntroduction: In South Africa, the optometric profession has seen two expansions of the scope of practice within the last two decades. The first of the two allowed optometrists to make use of techniques that required the use of diagnostic pharmaceutical agents. Aim: The purpose of the study was to establish the extent to which the four specific diagnostic techniques are utilised and if there exist barriers to their utilisation. Methods: A cross-sectional study was conducted to ascertain the utilisation of diagnostic techniques. The data was collected through a self-administered online questionnaire. The questionnaire contained questions on demographics, practice trends, utilisation of diagnostic techniques, as well as the registration status of the optometrists. Results: A total of 141 responses were received, and 118 were included for data analysis. There were 46 (39.0%) male participants and 72 (61.0%) were female. Ninety-eight (83.1%) of the participants had a diagnostic qualification, of which 49 (50.0%) were correctly registered with the HPCSA for diagnostic practice. Only 13.4% participants indicated that they performed contact tonometry at every visit, while slit-lamp fundus examinations was performed at every visit by 18.6% of the participants. BIO was only performed on indication by 20.8% of participants and gonioscopy was similarly only performed on indication by 34.7% of participants. Diagnostic techniques and procedures were mostly underutilised as many did not perform applanation tonometry (67.0%), binocular indirect ophthalmoscopy (79.2%), slit-lamp fundus examination (41.2%) and gonioscopy (64.3%). While optometrists were more confident in performing applanation tonometry (52.0%) and slit-lamp fundus examination (64.3%), confidence was considered a barrier for binocular indirect ophthalmoscopy (62.3%) and gonioscopy (54.1%). The lack of reimbursement was regarded as a significant barrier for 63.3% of participants, and 82.5% of respondents indicated the cost of acquiring the specific equipment was prohibitive. Most participants (92.8%) agreed that diagnostic privileges were appropriate for optometrists as well as the therapeutic scope of practice expansion (96.9%). Of those participants who were not correctly registered for diagnostic practice with the HPCSA, the majority (69.4%) were aware of the process to amend their registration status. The administrative process being too cumbersome and time-consuming was the most commonly stated barrier to amending the registration status of participants who were incorrectly registered. Conclusion: The study indicates that diagnostic techniques are mostly underutilised and optometrists prefer non-invasive alternative techniques over methods that are considered to be the gold standard. Another finding of the study is that there exists a discrepancy between the number of optometrists who are registered for diagnostic practice and the number of optometrists who have acquired a diagnostic qualification. It is recommended that an audit be done on the registration status of optometrists as to ascertain the correctness of the register and to have it amended if needed. It is further recommended that further studies should be done to ascertain the compliance of optometrists concerning their registrations and scope of practice. The reimbursement models need to be revisited, as well as the training of optometrists to ensure appropriate levels of confidence in diagnostic techniques amongst practitioners. These models should be geared towards professional services, emphasising the diagnosis and management of ocular diseases to motivate optometrists to practice more extensively within their full scope of practice