South African Journal of Science最新文献

{"title":"Association of accelerometry-based and self-reported physical activity with cardiovascular risk in South African children","authors":"Patricia Arnaiz, Felix Guntlisbergen, Denis Infanger, Markus Gerber, Larissa Adams, Danielle Dolley, Nandi Joubert, Madeleine Nienaber, Siphesihle Nqweniso, Rosa du Randt, Peter Steinmann, Jürg Utzinger, Cheryl Walter, Uwe Pühse, Ivan Müller","doi":"10.17159/sajs.2023/15494","DOIUrl":"https://doi.org/10.17159/sajs.2023/15494","url":null,"abstract":"The burden of non-communicable diseases is increasing, with risk factors emerging early in life. Physical activity reduces cardiovascular risk, but limited evidence exists for children from lower-income countries and mostly relies on self-reported methods that might be inaccurate and biased. We aimed to compare self-reported and accelerometer-measured physical activity in relation to cardiovascular risk markers in children from underserved communities in South Africa. We analysed cross-sectional data from 594 children aged 8 to 13. Physical activity was measured via accelerometry and the Physical Activity Questionnaire for Older Children (PAQ-C). Correlation analyses and linear regression models examined the relationship between accelerometer-measured and self-reported physical activity and their association with cardiovascular risk markers (body mass index, blood pressure, blood lipid profile and glycated haemoglobin). Results show a positive but weak correlation between PAQ-C scores and accelerometer-measured moderate-to-vigorous physical activity (MVPA). MVPA was inversely associated with body mass index, whilst sedentary behaviour correlated positively with lipid levels. PAQ-C scores were inversely associated with systolic blood pressure. The comparison of self-reported and accelerometer-measured physical activity in children from Gqeberha, South Africa, revealed inconsistencies in their correlation and association with cardiovascular risk markers. Accelerometry provided a more accurate cardiovascular risk estimation than PAQ-C, although associations were weak. Further, longitudinal studies should investigate the predictive power of both methodologies. These findings inform researchers and public health practitioners in the choice of method for physical activity appraisal beyond practical considerations, especially when combined with cardiovascular risk and in lower-income settings.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135344812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"One-pot hydrothermal green synthetic approach of fluorescent carbon dots as optical probes for 2-nitrophenol","authors":"Pogisego Dinake, Norma Phokedi, Mbhatshi M. Keetile, Mmamiki A. Botlhomilwe, Mogomotsi Tlhako, Bokang Present, Janes Mokgadi, Rosemary Kelebemang","doi":"10.17159/sajs.2023/13921","DOIUrl":"https://doi.org/10.17159/sajs.2023/13921","url":null,"abstract":"The pursuit of a cost-effective and green synthetic approach to chemical sensors and their application in the sensing of toxic and harmful substances is a never-ending exercise for scientists and researchers. Preparation of fluorescent carbon dots (C-dots) from biomass using water as a solvent and a hydrothermal autoclave to provide the required synthesis temperature offers a cheap and environmentally friendly synthetic approach. Herein, we report a faster, less costly and ecofriendly hydrothermal synthetic approach of carbon dots from Citrullus vulgaris peels as a precursor. The as-prepared carbon dots exhibited hydroxyl, carbonyl and amide functional groups on the surface and an amorphous structure with a particle size distribution of 1.7–3.0 nm. Moreover, the carbon dots displayed intense blue emission fluorescence at 470 nm after excitation at 400 nm. The as-prepared carbon dots demonstrated effective application without further modification towards the selective and sensitive optical recognition of 2-nitrophenol used in the manufacture of explosives. A limit of detection of 2.28×10−7 M was achieved, and no fluorescence quenching was observed in the presence of other nitroaromatic and benzene derivatives indicating excellent selectivity towards 2-nitrophenol. Finally, further studies are required to investigate the potential for the as-prepared carbon dots to monitor nitroaromatic pollutants in real environmental systems.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135385469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The value of multibeam bathymetry in marine spatial planning in South Africa: A review","authors":"Thamsanqa F. Wanda, Errol A. Wiles, Hayley C. Cawthra, Anton de Wit","doi":"10.17159/sajs.2023/14320","DOIUrl":"https://doi.org/10.17159/sajs.2023/14320","url":null,"abstract":"Given a growing global population and shift to embrace the blue economy, a need for marine spatial planning (MSP) has emerged in South Africa to sustainably resolve the rising conflicts over the use of marine and seabed resources and services. A well-developed marine spatial plan yields numerous ecological, social and economic benefits. These are achieved through mediating between spatially conflicting economic drivers’ interests (e.g. commercial fishing, tourism, mining), preventing their activities from compromising thresholds of an environment’s sustainability. Within the MSP framework, high-resolution geospatial datasets are required to document and describe the seabed in the highest possible detail. At any scale, integrated analysis of seabed geomorphology and habitats is anticipated to greatly improve the understanding of ecosystem functioning from a multidisciplinary perspective, whilst improving MSP procedures and management of marine space. South Africa is the first of few African countries to have an approved and implemented MSP framework, but is still somewhat behind globally in implementing large-scale regional hydroacoustic surveys to cover the country’s vast offshore territory. The deficiency of hydroacoustic surveys is perhaps due to a relative lack of funds and poor communication about the value of multibeam echo-sounder (MBES) derived data, whilst marine geoscience remains a scarce skill in the country. This review paper presents a geological perspective of MSP and explores (1) the value that seabed mapping offers MSP specifically and (2) the need to increase seabed mapping with MBES, using a recently initiated project from the South African east coast as a case study.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135344741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Responding to load shedding","authors":"Leslie Swartz","doi":"10.17159/sajs.2023/16836","DOIUrl":"https://doi.org/10.17159/sajs.2023/16836","url":null,"abstract":"","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135344744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Load shedding in South Africa: Another nail in income inequality?","authors":"R. Inglesi‐Lotz","doi":"10.17159/sajs.2023/16597","DOIUrl":"https://doi.org/10.17159/sajs.2023/16597","url":null,"abstract":"to","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45479359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Load shedding as a result of failures at the political-technological interface","authors":"M. Muller","doi":"10.17159/sajs.2023/16595","DOIUrl":"https://doi.org/10.17159/sajs.2023/16595","url":null,"abstract":"private-sector approaches to the management of traditionally public utility functions","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43808575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Some real but mostly unconsidered costs hiding in the dark corners of load shedding","authors":"M. J. Booysen, S. van der Berg, Pieter W. van der Walt","doi":"10.17159/sajs.2023/16596","DOIUrl":"https://doi.org/10.17159/sajs.2023/16596","url":null,"abstract":"Culling electrical demand to save a fickle supply costs South Africa more than you may think. Load shedding is South Africa’s new norm, affecting each of us, with individual impacts ranging from annoyance to ruin. Much of our vital and collective electrical lifeline is sacrificed on the altars of convenience, inefficiency, and oversight. This Commentary sheds light on some of the hidden costs of load shedding. We call for custodianship of this crucial and limited shared source of life, and call on government to incentivise electricity generation, preferably the renewable and distributed type.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49641528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Data gaps will leave scientists ‘in the dark’: How load shedding is obscuring our understanding of air quality","authors":"C. Wright, Matthew Benyon, N. Mahlangeni, T. Kapwata, T. Laban, R. Garland","doi":"10.17159/sajs.2023/16009","DOIUrl":"https://doi.org/10.17159/sajs.2023/16009","url":null,"abstract":"concentrations of pollutants are within acceptable levels for human health. For example, the 24-hour average standard for PM 2.5 (particulate matter with an aerodynamic diameter smaller than 2.5 µg/m 3 ) in South Africa is 20 µg/m 3 – this may be compared to the more stringent World Health Organization guideline of 5 µg/m 3 . 14 Data available on SAAQIS go through data validation processes and are checked for zero drift, which, if identified, is corrected based on values from the most recent in-situ calibration. In accordance with prescribed standard operating procedures, suspicious data spikes, negative values and other questionable data points are removed","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46126949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The impact of the increasing residential battery backup systems on load shedding","authors":"M. Ritchie, J. Engelbrecht, M. J. Booysen","doi":"10.17159/sajs.2023/16602","DOIUrl":"https://doi.org/10.17159/sajs.2023/16602","url":null,"abstract":"Load shedding has become the norm in South Africa. These rolling blackouts currently range from Stage 1 to Stage 6. Households are disempowered for 2–4 hours and for an average of 1.5–9 hours per day. In financially unequal South Africa, heavy users can afford battery backup solutions to keep the lights on. However, installing these at scale, without solar generation, eventually neuters the utility’s ability to stabilise the grid and avert a blackout with shedding. Here we assess and quantify the impact of these interventions using an electricity data set of 12 000 households.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41802265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Liquified petroleum gas provides a technically viable and financially feasible means to reduce Eskom’s diesel cost burden by 30% to 40%","authors":"S. Clark, C. McGregor","doi":"10.17159/sajs.2023/16594","DOIUrl":"https://doi.org/10.17159/sajs.2023/16594","url":null,"abstract":"plan are to expedite the review and approval of the queue of 6 GW of proposed private renewable generation projects and the commitment to encourage and enable commercial, industrial and residential rooftop solar projects. Once approvals are in place, these projects can be implemented quickly at any appropriate size","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41903477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}