首页 > 最新文献

South African Journal of Science最新文献

英文 中文
South African grasslands and ploughing: Outlook for agricultural expansion in Africa 南非草原与耕作:非洲农业扩张前景
4区 综合性期刊 Q2 Agricultural and Biological Sciences Pub Date : 2023-09-28 DOI: 10.17159/sajs.2023/15540
Elaine Slooten, Eulalia Jordaan, Joseph D.M. White, Sally Archibald, Frances Siebert
{"title":"South African grasslands and ploughing: Outlook for agricultural expansion in Africa","authors":"Elaine Slooten, Eulalia Jordaan, Joseph D.M. White, Sally Archibald, Frances Siebert","doi":"10.17159/sajs.2023/15540","DOIUrl":"https://doi.org/10.17159/sajs.2023/15540","url":null,"abstract":"","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135343337","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}
引用次数: 0
From waste cooking oil to oxygen-rich onion-like nanocarbons for the removal of hexavalent chromium from aqueous solutions 从废食用油到富氧洋葱状纳米碳用于去除水溶液中的六价铬
4区 综合性期刊 Q2 Agricultural and Biological Sciences Pub Date : 2023-09-28 DOI: 10.17159/sajs.2023/14006
Themba D. Ntuli, Ludwe L. Sikeyi, Thomas H. Mongwe, Orlette Mkhari, Neil J. Coville, Edward N. Nxumalo, Manoko S. Maubane-Nkadimeng
Vegetable cooking oil is used in domestic and commercial kitchens owing to its ability to modify and enhance the taste of the food through the frying process. However, as the oil is used through several frying cycles, it changes colour to dark brown and acquires an unpleasant smell. At this point, the waste oil is usually discarded, thereby finding its way into freshwater streams due to poor disposal and thus becoming an environmental pollutant. To provide an alternative, ‘green’ route to waste oil disposal, herein we report on the metal-free synthesis of onion-like nanocarbons (OLNCs) made from waste cooking oil via flame pyrolysis. The OLNCs were then applied in the removal of hexavalent chromium ions from aqueous solutions. The as-synthesised OLNCs were found to have similar properties (size, quasi-spherical shape etc.) to those synthesised from pure cooking oils. The Fourier-transform infrared spectroscopy data showed that the OLNCs contained C-O-type moieties which were attributed to the oxygenation process that took place during the cooking process. The OLNCs from waste oil were applied as an adsorbent for Cr(VI) and showed optimal removal conditions at pH = 2, t = 360 min, Co = 10 mg/L and Q0max = 47.62 mg/g, superior to data obtained from OLNCs prepared from pristine cooking oil. The results showed that the OLNCs derived from the waste cooking oil were effective in the removal of hexavalent chromium. Overall, this study shows how to repurpose an environmental pollutant (waste cooking oil) as an effective adsorbent for pollutant (Cr(VI)) removal.
植物油在家庭和商业厨房中使用,因为它能够通过油炸过程改变和提高食物的味道。然而,由于油经过几次油炸循环,它的颜色会变成深棕色,并产生难闻的气味。此时,废油通常被丢弃,由于处理不当而进入淡水溪流,成为环境污染物。为了提供一种替代的“绿色”废油处理途径,本文报道了利用废食用油通过火焰热解制备洋葱样纳米碳(olnc)的无金属合成方法。然后将olnc应用于从水溶液中去除六价铬离子。发现合成的olnc具有与纯食用油合成的olnc相似的性质(大小,准球形等)。傅里叶红外光谱数据表明,olnc中含有c - o型基团,这是由于在烹饪过程中发生的氧化过程造成的。用废油制备的olnc作为Cr(VI)的吸附剂,在pH = 2、t = 360 min、Co = 10 mg/L、Q0max = 47.62 mg/g的条件下对Cr(VI)的去除效果优于原始食用油制备的olnc。结果表明,从废食用油中提取的olnc对六价铬有较好的去除效果。总体而言,本研究展示了如何重新利用环境污染物(废食用油)作为污染物(Cr(VI))去除的有效吸附剂。
{"title":"From waste cooking oil to oxygen-rich onion-like nanocarbons for the removal of hexavalent chromium from aqueous solutions","authors":"Themba D. Ntuli, Ludwe L. Sikeyi, Thomas H. Mongwe, Orlette Mkhari, Neil J. Coville, Edward N. Nxumalo, Manoko S. Maubane-Nkadimeng","doi":"10.17159/sajs.2023/14006","DOIUrl":"https://doi.org/10.17159/sajs.2023/14006","url":null,"abstract":"Vegetable cooking oil is used in domestic and commercial kitchens owing to its ability to modify and enhance the taste of the food through the frying process. However, as the oil is used through several frying cycles, it changes colour to dark brown and acquires an unpleasant smell. At this point, the waste oil is usually discarded, thereby finding its way into freshwater streams due to poor disposal and thus becoming an environmental pollutant. To provide an alternative, ‘green’ route to waste oil disposal, herein we report on the metal-free synthesis of onion-like nanocarbons (OLNCs) made from waste cooking oil via flame pyrolysis. The OLNCs were then applied in the removal of hexavalent chromium ions from aqueous solutions. The as-synthesised OLNCs were found to have similar properties (size, quasi-spherical shape etc.) to those synthesised from pure cooking oils. The Fourier-transform infrared spectroscopy data showed that the OLNCs contained C-O-type moieties which were attributed to the oxygenation process that took place during the cooking process. The OLNCs from waste oil were applied as an adsorbent for Cr(VI) and showed optimal removal conditions at pH = 2, t = 360 min, Co = 10 mg/L and Q0max = 47.62 mg/g, superior to data obtained from OLNCs prepared from pristine cooking oil. The results showed that the OLNCs derived from the waste cooking oil were effective in the removal of hexavalent chromium. Overall, this study shows how to repurpose an environmental pollutant (waste cooking oil) as an effective adsorbent for pollutant (Cr(VI)) removal.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135385107","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}
引用次数: 0
Development of a chitosan-multi-walled carbon nanotubes composite for application in solid-phase adsorption toxin tracking of microcystins 壳聚糖-多壁碳纳米管复合材料在微囊藻毒素固相吸附追踪中的应用
4区 综合性期刊 Q2 Agricultural and Biological Sciences Pub Date : 2023-09-28 DOI: 10.17159/sajs.2023/14786
Glynn K. Pindihama, Mugera W. Gitari, Rabelani Mudzielwana, Ntakadzeni E. Madala
Contamination of water and food with cyanotoxins poses human health risks, and hence the need for sensitive early warning tools to monitor these in water. A composite of glutaraldehyde-crosslinked chitosan and multi-walled carbon nanotubes (ChMWCNTs) was synthesised and tested for potential use as a solid-phase adsorption toxin tracking (SPATT) adsorbent for monitoring microcystins (MCs) in fresh water. The composite was characterised by Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller theory and scanning electron microscopy. Batch adsorption experiments to assess the effect of contact time, adsorbent dosage and initial microcystin-LR (MC-LR) concentration were conducted. The composite was found to be efficient in adsorbing MC-LR, showing 97% removal and a maximum adsorption capacity of 4.639 μg/g under optimised conditions of 5 μg/L of MC-LR, adsorbent dose of 0.03 g/5 mL and 30 min contact time. The adsorption kinetics were better explained by a pseudo-second-order model, inferring chemisorption adsorption. The isotherm data better fitted the Langmuir isotherm model, thus inferring monolayer surface adsorption. For desorption, 100% methanol was the most effective, with an efficiency of 84.71%. The composite effectively adsorbed and desorbed three congeners of MCs (–LR, –RR and –YR) when tested in raw dam water, regardless of its lower maximum adsorption capacity compared to those of other adsorbents used for similar purposes.
被蓝藻毒素污染的水和食物对人类健康构成威胁,因此需要敏感的早期预警工具来监测水中的这些情况。合成了戊二醛交联壳聚糖和多壁碳纳米管(ChMWCNTs)的复合材料,并对其作为固相吸附毒素跟踪(SPATT)吸附剂用于监测淡水中微囊藻毒素(MCs)的潜力进行了测试。利用傅里叶变换红外光谱、布鲁诺尔-埃米特-泰勒理论和扫描电镜对复合材料进行了表征。通过批量吸附实验考察了接触时间、吸附剂用量和初始微囊藻毒素- lr (MC-LR)浓度的影响。在MC-LR浓度为5 μg/L、吸附剂剂量为0.03 g/5 mL、接触时间为30 min的优化条件下,复合材料对MC-LR的去除率为97%,最大吸附量为4.639 μg/g。吸附动力学较好地解释了伪二阶模型,推断化学吸附。等温线数据较好地拟合Langmuir等温线模型,从而推断单层表面吸附。100%甲醇解吸效果最好,解吸效率为84.71%。当在原坝水中测试时,复合材料有效地吸附和解吸了三种MCs同系物(-LR, -RR和-YR),尽管与其他类似用途的吸附剂相比,其最大吸附容量较低。
{"title":"Development of a chitosan-multi-walled carbon nanotubes composite for application in solid-phase adsorption toxin tracking of microcystins","authors":"Glynn K. Pindihama, Mugera W. Gitari, Rabelani Mudzielwana, Ntakadzeni E. Madala","doi":"10.17159/sajs.2023/14786","DOIUrl":"https://doi.org/10.17159/sajs.2023/14786","url":null,"abstract":"Contamination of water and food with cyanotoxins poses human health risks, and hence the need for sensitive early warning tools to monitor these in water. A composite of glutaraldehyde-crosslinked chitosan and multi-walled carbon nanotubes (ChMWCNTs) was synthesised and tested for potential use as a solid-phase adsorption toxin tracking (SPATT) adsorbent for monitoring microcystins (MCs) in fresh water. The composite was characterised by Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller theory and scanning electron microscopy. Batch adsorption experiments to assess the effect of contact time, adsorbent dosage and initial microcystin-LR (MC-LR) concentration were conducted. The composite was found to be efficient in adsorbing MC-LR, showing 97% removal and a maximum adsorption capacity of 4.639 μg/g under optimised conditions of 5 μg/L of MC-LR, adsorbent dose of 0.03 g/5 mL and 30 min contact time. The adsorption kinetics were better explained by a pseudo-second-order model, inferring chemisorption adsorption. The isotherm data better fitted the Langmuir isotherm model, thus inferring monolayer surface adsorption. For desorption, 100% methanol was the most effective, with an efficiency of 84.71%. The composite effectively adsorbed and desorbed three congeners of MCs (–LR, –RR and –YR) when tested in raw dam water, regardless of its lower maximum adsorption capacity compared to those of other adsorbents used for similar purposes.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135343338","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}
引用次数: 0
GYPWORLD Africa: Setting an agenda for gypsum ecosystem research in southern Africa 非洲石膏世界:为南部非洲的石膏生态系统研究制定议程
4区 综合性期刊 Q2 Agricultural and Biological Sciences Pub Date : 2023-09-28 DOI: 10.17159/sajs.2023/15308
Stefan J. Siebert, Sara Palacio, Arantzazu L. Luzuriaga, Gillian Maggs-Kölling, Eugene Marais, Silvia Matesanz, María Prieto, Yolanda Pueyo, Nishanta Rajakaruna, Ana M. Sánchez, Sarina Claassens
This paper introduces gypsum ecosystem research to southern Africa. It is the result of current joint efforts to compare African gypsum ecosystems with those in other parts of the world. We highlight the expansion of an international network through joint projects and training of young scientists. We propose a research agenda to sensitise the ecological community in Africa to the significance of life on gypsum and to demystify the existence of gypsum soil and associated ecosystems in southern Africa. Gypsum ecosystem research is rapidly moving up the international research agenda to better understand the dynamics and resilience of the life systems associated with atypical soils that are frequent in semi-arid to arid ecosystems. The southern African soil classification system does not sufficiently recognise the presence of gypsum as a differentiating criterion, hence not much is known about the region’s gypsum soil, and gypsum ecology has subsequently been largely neglected. This neglect is unfortunate, as the livelihoods of people are dependent on these gypsum ecosystems and these areas are worthy of protection due to the rare biotas that are adapted to survive in these harsh environments.
{"title":"GYPWORLD Africa: Setting an agenda for gypsum ecosystem research in southern Africa","authors":"Stefan J. Siebert, Sara Palacio, Arantzazu L. Luzuriaga, Gillian Maggs-Kölling, Eugene Marais, Silvia Matesanz, María Prieto, Yolanda Pueyo, Nishanta Rajakaruna, Ana M. Sánchez, Sarina Claassens","doi":"10.17159/sajs.2023/15308","DOIUrl":"https://doi.org/10.17159/sajs.2023/15308","url":null,"abstract":"This paper introduces gypsum ecosystem research to southern Africa. It is the result of current joint efforts to compare African gypsum ecosystems with those in other parts of the world. We highlight the expansion of an international network through joint projects and training of young scientists. We propose a research agenda to sensitise the ecological community in Africa to the significance of life on gypsum and to demystify the existence of gypsum soil and associated ecosystems in southern Africa. Gypsum ecosystem research is rapidly moving up the international research agenda to better understand the dynamics and resilience of the life systems associated with atypical soils that are frequent in semi-arid to arid ecosystems. The southern African soil classification system does not sufficiently recognise the presence of gypsum as a differentiating criterion, hence not much is known about the region’s gypsum soil, and gypsum ecology has subsequently been largely neglected. This neglect is unfortunate, as the livelihoods of people are dependent on these gypsum ecosystems and these areas are worthy of protection due to the rare biotas that are adapted to survive in these harsh environments.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135343344","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}
引用次数: 0
Physical anthropology through the eyes of the scientists 科学家眼中的体质人类学
4区 综合性期刊 Q2 Agricultural and Biological Sciences Pub Date : 2023-09-28 DOI: 10.17159/sajs.2023/16804
Himla Soodyall
Book Review In Bones and Bodies, Alan Morris brings to life the historic narrative of how “the skeletons I study were once the frames of living people” (p. 2) and how “biological information can have no value without understanding the social and cultural context of the people” (p. 2). Morris ploughed through collections of correspondence between early researchers in the field and volumes of literature, and conducted interviews with seminal figures in the fields of physical anthropology, archaeology and palaeontology, among others, to eloquently narrate the contribution of scholars who shaped the physical anthropology landscape in South Africa.
{"title":"Physical anthropology through the eyes of the scientists","authors":"Himla Soodyall","doi":"10.17159/sajs.2023/16804","DOIUrl":"https://doi.org/10.17159/sajs.2023/16804","url":null,"abstract":"Book Review In Bones and Bodies, Alan Morris brings to life the historic narrative of how “the skeletons I study were once the frames of living people” (p. 2) and how “biological information can have no value without understanding the social and cultural context of the people” (p. 2). Morris ploughed through collections of correspondence between early researchers in the field and volumes of literature, and conducted interviews with seminal figures in the fields of physical anthropology, archaeology and palaeontology, among others, to eloquently narrate the contribution of scholars who shaped the physical anthropology landscape in South Africa.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135344739","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}
引用次数: 0
Accessory gene regulators and virulence genes associated with the pathogenicity of Staphylococcus aureus from clinical and community settings in Lagos, Nigeria 尼日利亚拉各斯临床和社区环境中与金黄色葡萄球菌致病性相关的辅助基因调控因子和毒力基因
4区 综合性期刊 Q2 Agricultural and Biological Sciences Pub Date : 2023-09-28 DOI: 10.17159/sajs.2023/10901
Nkechi V. Enwuru, Solayide A. Adesida, Christian A. Enwuru, Udoma E. Mendie
Staphylococcus aureus is a prominent pathogen that causes serious community and hospital-acquired infections globally. Its pathogenicity is attributed to a variety of secreted and cell surface associated proteins that are modulated by the quorum-sensing accessory gene regulator (agr) system. In this study, we investigated the presence of toxin genes and agr involved with S. aureus from clinical samples and apparently healthy individuals. Unequivocal identification of the isolates was obtained with the Vitek 2 system. We screened 70 clinical (CL) and 22 community (C) S. aureus strains for the methicillin resistance (mecA) gene, agr and superantigens (SAg) (enterotoxins and toxic shock syndrome toxin-1) using PCR techniques. A total of 12 clinical isolates were classified as methicillin-resistant S. aureus (MRSA); 89 isolates belonged to one of the four agr groups (agr1-4), and 3 isolates were non-typeable. Of the agr groups, agr1 was the most prominent and mostly consisted of isolates from pus/wounds. The methicillin-susceptible S. aureus (MSSA) isolates were distributed within the four agr groups while MRSA strains were restricted to agr1 and agr3. The most common enterotoxin gene, sei, was likewise more prevalent in MSSA strains than in MRSA strains, where sea predominated. The co-existence of two or more enterotoxins was confirmed in 40% of the isolates. sea occurred through all the agr groups except agr3 and sei was not found in agr1 and agr4. The toxic shock toxin (tst) gene was detected in six MSSA. These findings suggest that MSSA may cause more lethal infections than MRSA because of the increased frequency of toxic genotypes seen in MSSA strains.
金黄色葡萄球菌是全球范围内引起严重社区和医院获得性感染的重要病原体。其致病性归因于多种分泌蛋白和细胞表面相关蛋白,这些蛋白由群体感应辅助基因调节器(agr)系统调节。在这项研究中,我们从临床样本和表面健康的个体中调查了金黄色葡萄球菌涉及的毒素基因和agr的存在。用Vitek 2系统对分离株进行了明确的鉴定。我们采用PCR技术筛选了70株临床(CL)和22株社区(C)金黄色葡萄球菌耐甲氧西林(mecA)基因、agr和超级抗原(SAg)(肠毒素和中毒性休克综合征毒素-1)。12株临床分离株被分类为耐甲氧西林金黄色葡萄球菌(MRSA);89株分离株属于4个agr类群(ag1 ~ 4)之一,3株分离株不可分型。在agr组中,agr1最为突出,主要由脓液/伤口分离株组成。甲氧西林敏感金黄色葡萄球菌(MSSA)分布在4个agr组中,MRSA菌株仅局限于agr1和agr3。同样,最常见的肠毒素基因sei在MSSA菌株中比在MRSA菌株中更为普遍,后者以sea为主。在40%的分离株中证实存在两种或两种以上的肠毒素。除ag3外,其余agr组均出现Sea,而在ag1和ag4中未发现sei。在6例MSSA中检测到毒性休克毒素(tst)基因。这些发现表明,MSSA可能比MRSA引起更致命的感染,因为MSSA菌株中毒性基因型的频率增加。
{"title":"Accessory gene regulators and virulence genes associated with the pathogenicity of Staphylococcus aureus from clinical and community settings in Lagos, Nigeria","authors":"Nkechi V. Enwuru, Solayide A. Adesida, Christian A. Enwuru, Udoma E. Mendie","doi":"10.17159/sajs.2023/10901","DOIUrl":"https://doi.org/10.17159/sajs.2023/10901","url":null,"abstract":"Staphylococcus aureus is a prominent pathogen that causes serious community and hospital-acquired infections globally. Its pathogenicity is attributed to a variety of secreted and cell surface associated proteins that are modulated by the quorum-sensing accessory gene regulator (agr) system. In this study, we investigated the presence of toxin genes and agr involved with S. aureus from clinical samples and apparently healthy individuals. Unequivocal identification of the isolates was obtained with the Vitek 2 system. We screened 70 clinical (CL) and 22 community (C) S. aureus strains for the methicillin resistance (mecA) gene, agr and superantigens (SAg) (enterotoxins and toxic shock syndrome toxin-1) using PCR techniques. A total of 12 clinical isolates were classified as methicillin-resistant S. aureus (MRSA); 89 isolates belonged to one of the four agr groups (agr1-4), and 3 isolates were non-typeable. Of the agr groups, agr1 was the most prominent and mostly consisted of isolates from pus/wounds. The methicillin-susceptible S. aureus (MSSA) isolates were distributed within the four agr groups while MRSA strains were restricted to agr1 and agr3. The most common enterotoxin gene, sei, was likewise more prevalent in MSSA strains than in MRSA strains, where sea predominated. The co-existence of two or more enterotoxins was confirmed in 40% of the isolates. sea occurred through all the agr groups except agr3 and sei was not found in agr1 and agr4. The toxic shock toxin (tst) gene was detected in six MSSA. These findings suggest that MSSA may cause more lethal infections than MRSA because of the increased frequency of toxic genotypes seen in MSSA strains.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135344760","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}
引用次数: 0
Building a carbon dioxide removal science–policy partnership for southern Africa 为南部非洲建立二氧化碳清除科学-政策伙伴关系
4区 综合性期刊 Q2 Agricultural and Biological Sciences Pub Date : 2023-09-28 DOI: 10.17159/sajs.2023/16320
Pedro M.S. Monteiro, Guy F. Midgley
which will impact society through carbon pricing, management of climate risk, and the costs of adaptation and mitigation. Finally, there are risks related to the as-yet uncertain feasibility and scalability of the technological interventions, such as direct air capture of CO 2 , biomass energy with carbon capture (BECCS)
{"title":"Building a carbon dioxide removal science–policy partnership for southern Africa","authors":"Pedro M.S. Monteiro, Guy F. Midgley","doi":"10.17159/sajs.2023/16320","DOIUrl":"https://doi.org/10.17159/sajs.2023/16320","url":null,"abstract":"which will impact society through carbon pricing, management of climate risk, and the costs of adaptation and mitigation. Finally, there are risks related to the as-yet uncertain feasibility and scalability of the technological interventions, such as direct air capture of CO 2 , biomass energy with carbon capture (BECCS)","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135385232","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}
引用次数: 0
An assessment of the economic impact of South Africa’s public universities 对南非公立大学经济影响的评估
4区 综合性期刊 Q2 Agricultural and Biological Sciences Pub Date : 2023-09-28 DOI: 10.17159/sajs.2023/14851
Ahmed C. Bawa, Anastassios Pouris
With the understanding that universities play multiple social purposes, we aimed to provide an estimation of the economic impact of the public universities in South Africa. Using models described in the literature, we estimated economic benefits from four university activities – university exports, research at universities, the production of graduates and universities as business entities. Comparative analysis shows that, as an economic sector, Higher Education contributes more to South Africa’s gross value added than other economic sectors such as Wood and Wood Products, Textiles, Clothing and Leather Goods, or Paper and Paper Products. It is comparable to sectors such as Gold Mining, and Beverages and Tobacco. Taking into account a number of assumptions, which are explained in the text, for 2018 the total economic impact was estimated at about ZAR513 billion. Governmental expenditure on higher education in that year was ZAR66 billion. These figures produce a cost–benefit ratio for the sector of 1 : 7.7, considering only these four university activities.
了解到大学具有多重社会目的后,我们的目的是对南非公立大学的经济影响进行评估。使用文献中描述的模型,我们估计了四种大学活动的经济效益——大学出口、大学研究、毕业生生产和大学作为商业实体。比较分析表明,作为一个经济部门,高等教育对南非总增加值的贡献大于其他经济部门,如木材和木制品、纺织品、服装和皮革制品或纸张和纸制品。这与黄金矿业、饮料和烟草等行业相当。考虑到文本中解释的一些假设,2018年的总经济影响估计约为5130亿兰特。那一年,政府在高等教育方面的支出为660亿兰特。仅考虑这四所大学的活动,这些数字产生的成本效益比为1:7 7。
{"title":"An assessment of the economic impact of South Africa’s public universities","authors":"Ahmed C. Bawa, Anastassios Pouris","doi":"10.17159/sajs.2023/14851","DOIUrl":"https://doi.org/10.17159/sajs.2023/14851","url":null,"abstract":"With the understanding that universities play multiple social purposes, we aimed to provide an estimation of the economic impact of the public universities in South Africa. Using models described in the literature, we estimated economic benefits from four university activities – university exports, research at universities, the production of graduates and universities as business entities. Comparative analysis shows that, as an economic sector, Higher Education contributes more to South Africa’s gross value added than other economic sectors such as Wood and Wood Products, Textiles, Clothing and Leather Goods, or Paper and Paper Products. It is comparable to sectors such as Gold Mining, and Beverages and Tobacco. Taking into account a number of assumptions, which are explained in the text, for 2018 the total economic impact was estimated at about ZAR513 billion. Governmental expenditure on higher education in that year was ZAR66 billion. These figures produce a cost–benefit ratio for the sector of 1 : 7.7, considering only these four university activities.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135344809","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}
引用次数: 0
Charles Kimberlin (Bob) Brain (1931–2023): Naturalist, scientific leader, and family man 查尔斯·金伯林(鲍勃)·布莱恩(1931-2023):博物学家、科学领袖和居家男人
4区 综合性期刊 Q2 Agricultural and Biological Sciences Pub Date : 2023-09-28 DOI: 10.17159/sajs.2023/16660
Bruce Rubidge
{"title":"Charles Kimberlin (Bob) Brain (1931–2023): Naturalist, scientific leader, and family man","authors":"Bruce Rubidge","doi":"10.17159/sajs.2023/16660","DOIUrl":"https://doi.org/10.17159/sajs.2023/16660","url":null,"abstract":"","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135343342","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}
引用次数: 0
Assessing the adoption of improved seeds as a coping strategy to climate variability under smallholder farming conditions in South Africa 评估在南非小农条件下采用改良种子作为应对气候变化的策略
4区 综合性期刊 Q2 Agricultural and Biological Sciences Pub Date : 2023-09-28 DOI: 10.17159/sajs.2023/15001
Lindumusa Myeni, Mokhele E. Moeletsi
This study was undertaken to examine the adoption rate, constraints and factors determining the uptake of improved seed varieties in smallholder farming conditions of South Africa, using a maize crop. Primary data were collected from 279 smallholder farmers in the Maluti-a-Phofung municipality of the Free State Province using a household questionnaire and were validated through focus group discussions with key local informants. Descriptive statistics, frequency analysis and a binary logistic model were used for data analysis. Results show that the majority of the farmers (>69%) were growing uncertified local seed varieties saved from their previous harvest or acquired from neighbouring farmers. The lack of awareness and knowledge of, inadequate information, unaffordability and unavailability of improved seeds, low income and landlessness were major constraints limiting the adoption rate. Age and income were the main variables that had a positive and significant effect on the adoption of improved seed varieties, whilst ownership of livestock had a significant and negative influence on their adoption. As a result, the promotion of improved seed varieties needs to be supported by conducive and effectual institutional policies that will improve the provision of extension services, capacity-building initiatives, subsidy programmes, financial resources and good agricultural lands, and reduce the transaction costs of improved seed varieties. The recommendations from this study can be used by the government and other developmental organisations to enhance the wider uptake and use of improved seed varieties in smallholder farming conditions not only in the study area but also in other regions with similar challenges.
进行这项研究的目的是审查南非小农条件下使用玉米作物的改良种子品种的采用率、制约因素和决定因素。使用家庭调查问卷从自由邦省malutia - phofung市的279个小农那里收集了初步数据,并通过与当地主要举报人进行焦点小组讨论加以验证。采用描述性统计、频率分析和二元logistic模型进行数据分析。结果表明,大多数农民(69%)种植的是未经认证的本地种子品种,这些种子品种是从他们以前的收获中保存下来的,或者是从邻近农民那里获得的。缺乏认识和知识、信息不足、负担不起和得不到改良种子、收入低和无地是限制采用率的主要制约因素。年龄和收入是对采用改良种子品种产生积极和显著影响的主要变量,而牲畜所有权对采用改良种子品种产生显著的消极影响。因此,推广改良种子品种需要得到有利和有效的体制政策的支持,这些政策将改善提供推广服务、能力建设倡议、补贴方案、财政资源和良好的农业用地,并降低改良种子品种的交易成本。这项研究的建议可以被政府和其他发展组织使用,不仅在研究地区,而且在其他面临类似挑战的地区,在小农农业条件下加强对改良种子品种的更广泛吸收和使用。
{"title":"Assessing the adoption of improved seeds as a coping strategy to climate variability under smallholder farming conditions in South Africa","authors":"Lindumusa Myeni, Mokhele E. Moeletsi","doi":"10.17159/sajs.2023/15001","DOIUrl":"https://doi.org/10.17159/sajs.2023/15001","url":null,"abstract":"This study was undertaken to examine the adoption rate, constraints and factors determining the uptake of improved seed varieties in smallholder farming conditions of South Africa, using a maize crop. Primary data were collected from 279 smallholder farmers in the Maluti-a-Phofung municipality of the Free State Province using a household questionnaire and were validated through focus group discussions with key local informants. Descriptive statistics, frequency analysis and a binary logistic model were used for data analysis. Results show that the majority of the farmers (>69%) were growing uncertified local seed varieties saved from their previous harvest or acquired from neighbouring farmers. The lack of awareness and knowledge of, inadequate information, unaffordability and unavailability of improved seeds, low income and landlessness were major constraints limiting the adoption rate. Age and income were the main variables that had a positive and significant effect on the adoption of improved seed varieties, whilst ownership of livestock had a significant and negative influence on their adoption. As a result, the promotion of improved seed varieties needs to be supported by conducive and effectual institutional policies that will improve the provision of extension services, capacity-building initiatives, subsidy programmes, financial resources and good agricultural lands, and reduce the transaction costs of improved seed varieties. The recommendations from this study can be used by the government and other developmental organisations to enhance the wider uptake and use of improved seed varieties in smallholder farming conditions not only in the study area but also in other regions with similar challenges.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135421120","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}
引用次数: 0
期刊
South African Journal of Science
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1