Benefits of maize resistance breeding and chemical control against northern leaf blight in smallholder farms in South Africa

Maize underpins food security in South Africa. An annual production of more than 10 million tons is a combination of the output of large-scale commercial farms plus an estimated 250 000 ha cultivated by smallholder farmers. Maize leaves are a rich source of nutrients for fungal pathogens. Farmers must limit leaf blighting by fungi to prevent sugars captured by photosynthesis being ‘stolen’ instead of filling the grain. This study aimed to fill the knowledge gap on the prevalence and impact of fungal foliar diseases in local smallholder maize fields. A survey with 1124 plant observations from diverse maize hybrids was conducted over three seasons from 2015 to 2017 in five farming communities in KwaZulu-Natal Province (Hlanganani, Ntabamhlophe, KwaNxamalala) and Eastern Cape Province (Bizana, Tabankulu). Northern leaf blight (NLB), common rust, Phaeosphaeria leaf spot, and grey leaf spot had overall disease incidences of 75%, 77%, 68% and 56%, respectively, indicating high disease pressure in smallholder farming environments. NLB had the highest disease severity (LSD test, p<0.05). A yield trial focused on NLB in KwaZulu-Natal showed that this disease reduced yields in the three most susceptible maize hybrids by 36%, 71% and 72%, respectively. Eighteen other hybrids in this trial did not show significant yield reductions due to NLB, which illustrates the progress made by local maize breeders in disease resistance breeding. This work highlights the risk to smallholder farmers of planting disease-susceptible varieties, and makes recommendations on how to exploit the advances of hybrid maize disease resistance breeding to develop farmer-preferred varieties for smallholder production. SIGNIFICANCE : • Northern leaf blight, grey leaf spot, Phaeosphaeria leaf spot and common rust diseases were widespread in KwaZulu-Natal and Eastern Cape smallholder maize fields where fungicides were not applied. • NLB was the most severe maize leaf disease overall. • NLB caused maize leaf blighting, which reduced grain yields by 36–72% in susceptible maize hybrids. • Maize resistance breeding has produced locally adapted hybrids that do not have significant yield losses under NLB disease pressure.Department of Agriculture, Forestry and Fisheries Research Technology Fund through the National Research Foundation of South Africa; USAID through the University of California Davis Research and Innovation Fellowship for Agriculture.http://www.sajs.co.zaam2021BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant PathologyPlant Production and Soil Scienc

Health Outcomes of Exposure to Biological and Chemical Components of Inhalable and Respirable Particulate Matter

Particulate matter (PM) is a key indicator of air pollution and a significant risk factor for adverse health outcomes in humans. PM is not a self-contained pollutant but a mixture of different compounds including chemical and biological fractions. While several reviews have focused on the chemical components of PM and associated health effects, there is a dearth of review studies that holistically examine the role of biological and chemical components of inhalable and respirable PM in disease causation. A literature search using various search engines and (or) keywords was done. Articles selected for review were chosen following predefined criteria, to extract and analyze data. The results show that the biological and chemical components of inhalable and respirable PM play a significant role in the burden of health effects attributed to PM. These health outcomes include low birth weight, emergency room visit, hospital admission, respiratory and pulmonary diseases, cardiovascular disease, cancer, non-communicable diseases, and premature death, among others. This review justifies the importance of each or synergistic effects of the biological and chemical constituents of PM on health. It also provides information that informs policy on the establishment of exposure limits for PM composition metrics rather than the existing exposure limits of the total mass of PM. This will allow for more effective management strategies for improving outdoor air quality

Manganese promotes increased formation of hydrogen peroxide by activated human macrophages and neutrophils in vitro

Although pro-inflammatory mechanisms have been implicated in the pathogenesis of manganese (Mn²⁺)-related neurological and respiratory disorders, relatively little is known about the potential of this metal to interact pro-oxidatively with human phagocytes. The primary objective of the current study was to investigate the effects of Mn²⁺ as MnCl₂ (0.5-100 µM) on the generation of the reactive oxygen species (ROS), superoxide, hydrogen peroxide (H₂O₂), and hypohalous acids by isolated human blood neutrophils and monocyte-derived macrophages following activation of these cells with the chemotactic tripeptide, FMLP (1 µM), or the phorbol ester, PMA (25 ng/mL). Generation of ROS was measured using the combination of oxygen consumption, lucigenin/luminol-enhanced chemiluminescence, spectrofluorimetric detection of oxidation of 2,7-dichlorodihydrofluorescein, radiometric assessment of myeloperoxidase (MPO)-mediated protein iodination, release of MPO by ELISA, and spectrophotometric measurement of nitrite formation. Treatment of activated neutrophils with either FMLP or PMA resulted in significantly decreased reactivity of superoxide in the setting of increased formation of H₂O₂ and MPO-mediated iodination, with no detectable effects on either oxygen consumption or MPO release. Similar effects of the metal with respect to superoxide reactivity and H₂O₂ formation were observed with activated macrophages, while generation of NO was unaffected. Taken together with the findings of experiments using cell-free ROS-generating systems, these observations are compatible with a mechanism whereby Mn²⁺, by acting as a superoxide dismutase mimetic, increases the formation of H₂O₂ by activated phagocytes. If operative in vivo, this mechanism may contribute to the toxicity of Mn²⁺http://www.tandfonline.com/loi/iiht20hb2016Immunolog

Needs assessment to strengthen capacity in water and sanitation research in Africa:experiences of the African SNOWS consortium

Despite its contribution to global disease burden, diarrhoeal disease is still a relatively neglected area for research funding, especially in low-income country settings. The SNOWS consortium (Scientists Networked for Outcomes from Water and Sanitation) is funded by the Wellcome Trust under an initiative to build the necessary research skills in Africa. This paper focuses on the research training needs of the consortium as identified during the first three years of the project

The pedagogy of initial reading at Sizwile School for the Deaf

M.Ed. (Educational Linguistics)The construct of this study consists of the perceptions and experiences of the teachers and students of initial reading at Sizwile School for the Deaf in urban South Africa. This investigation focuses on a Sub B class, in which Sign Language is the means of communication. The research design is exploratory and descriptive as it aims to explore, describe and clarify the children's apprehension of reading. This could yield new knowledge which is rooted in a specific and complex context. The process is conducted by means of a case study (monographic study) design which includes mostly qualitative methods for data collection. The rationale for this study is that respondents' personal (ernic) views, obtained from a "bottom-up" research mode could bring more light to the body of knowledge of deaf education in South Africa. Insufficient rigorous research, the lack of educational policy, lack of more input in South African curriculum for the deaf and limited cohesive instructional theory in South African deaf education motivated the researcher to initiate this investigation. The rationale of this stidy thus circulated from the theoretical and physical context of deaf education in South Africa, as well as the researcher's personal experiential knowledge as a teacher in the only school for the deaf around Soweto (a Black Township). The research question in this inquiry has been conceptualised in a maze of conflicting opinions and practices regarding the education of the deaf and the teaching of initial reading. The experiences, activities and perceptions of a single class within a school for the deaf was explored and described argumentatively in the light of contemporary theories on language, learning, reading and deaf education. Perspectives on learning to read are discussed in order to contextualise the individual's learning to read. Also included are theories of language and of learning, presented to provide a backdrop against which the practices in deaf education will be discussed. Language is subsequently discussed as medium of communication in the education process, with a closer focus on instruction in the first language (Sign Language) of the deaf child. The other part of the conceptual framework covers reading across the curriculum. The theoretical framework is presented as support structure for the research construct and also to problematise the research question (problem) from complementary angles

The Impact of Technology on a Democratic Political System in South Africa

The democratisation process in South Africa has subjected the country to the global effects of the challenges that culminated in a nation that is facing the demands for socioecomonic needs coupled with technological advancement. Advances in technology in the global arena present both opportunities and threats to the South African democracy and its concomitant socioeconomic imperatives. The democratisation process in South Africa is consequential to the inextricably bound relationship between technology, modernisation and democracy. This triad pattern precipitates the South African democratic political system. Advances in technology are also imperative for human and national security, but the intensity of pervasiveness may have serious ramifications for the appraisal for political stability in a democratic South Africa. Technology is one of the major sources underpinning and strengthening democracy in a political system. However, technology also affects the daily life of the ordinary citizen, depending on the manner in which decisions are made to implement a technology policy. The South African government through its technology approach has an action plan for growth, which aims to set the economy on a more competitive footing. The action plan engages major technological projects to benefit the broader society but overlooks a major factor in the "democratic theory of technology", namely the imperative that communities be consulted about technology decisions. These efforts are concerned exclusively with democratic procedures in making policy decisions about technologies. The South African government in 1996 reformed its technology policy approach so as to ensure that democratic values are prevalent and that citizens have access to technology. This policy approach raises concern about improving the democratic and the socioeconomic wellbeing of society, while inversely there is the uncertainty whether advances in technology can support and enhance the intended policy approach in the democratisation process in South Africa. This problem of whether technologies are substantively democratic, that is whether technology policy decisions are compatible with perpetuating a democratic political system, resulted in the need to investigate and appraise democratic theories and further critically analyse approaches and challenges in democratic politics of technology within the South African democratic political system. The study looks at the role and magnitude of technology in a democratic South Africa. It presents and argues the hypothesis that “greater advance in technology tends to enhance the democratisation process in a political system”. Much of the argument is devoted to providing evidence that technology influences both human and national security and as such demonstrates how technology as a systematic application of knowledge to resources can provide a good tool for sustaining democracy in South Africa. Technology is ubiquitous within South Africa’s democratic political system and it may be considered a boon or bane. It encompasses both benefits and disadvantages such that it poses complex options for a democratic political system in both its approach and implementation within a policy framework. The social dichotomy of this policy framework raises the need for further inquiry as to the reasoning and application of technology in addressing socioeconomic imperatives for concretising democracy, thus creating “a better life for all”. The democratic imperatives within the policy framework dictate an analysis to the ventured hypothesis that “advances in technology will enhance democracy in a political system”, and it is in this regard that South Africa is used as an archetype to disembark at a logical deduction to validate this hypothesis in the study.Thesis (PhD (Political Sciences))--University of Pretoria, 2006.Political Sciencesunrestricte

Potential of space science technology for water infrastructure management: A literature review

This article examines the potential of space science technology for water infrastructure (WI) management. It defines space technology in detail, and when South Africa (SA) started using it as a tool. To explain the context, the different types of orbits, altitudes, and functions of satellites are given, as well as the challenges that satellites encounter in orbit, including the quantity and sizes of orbital debris also known as space junk. The article articulates the international and local challenges to WI and further introduces space technology as a tool that can assist to overcome the challenges. Legislation governing the application of space technology in SA is discussed and the different satellites owned by the various space agencies of Africa are outlined. A discussion on how space technology has boosted the economies and employment in Africa and South Africa is provided. How the various applications of the technology, such as remote sensing (RS), Earth observation (Eo), Geo-Information sciences, navigation, communication, safety, and security can assist WI management are discussed. Details about the involvement of various African and SA universities and colleges in space science programmes that benefit the communities are explained. Also outlined are some experiments performed on the International Space Station (ISS) that benefit the Earth and that could be useful to WI management

Potential of space science technology for water infrastructure management: A literature review

This article examines the potential of space science technology for water infrastructure (WI) management. It defines space technology in detail, and when South Africa (SA) started using it as a tool. To explain the context, the different types of orbits, altitudes, and functions of satellites are given, as well as the challenges that satellites encounter in orbit, including the quantity and sizes of orbital debris also known as space junk. The article articulates the international and local challenges to WI and further introduces space technology as a tool that can assist to overcome the challenges. Legislation governing the application of space technology in SA is discussed and the different satellites owned by the various space agencies of Africa are outlined. A discussion on how space technology has boosted the economies and employment in Africa and South Africa is provided. How the various applications of the technology, such as remote sensing (RS), Earth observation (Eo), Geo-Information sciences, navigation, communication, safety, and security can assist WI management are discussed. Details about the involvement of various African and SA universities and colleges in space science programmes that benefit the communities are explained. Also outlined are some experiments performed on the International Space Station (ISS) that benefit the Earth and that could be useful to WI management

Challenges during installation and maintenance of water delivery infrastructure: a citizen perspective

The installation and maintenance of water infrastructure in South African cities poses a challenge to communities, municipalities, and installation contractors, who face problems such as inadequate access to homes, traffic jams, inadequately barricaded trenches, leaking water pipes, water supply cut-offs, vandalism, and theft of water. The research problem, therefore, involves an inadequate understanding of what drives these problems and how to mitigate them through better management. The aim of this study was to investigate the challenges of managing water infrastructure as perceived by the citizens of a South African municipality. The study was a descriptive and cross-sectional survey, with data collected, via a literature derived, emailed questionnaire, from a self-selected non-probability sample of 402 City of Tshwane residents. Analysis, via SPSS Version 27, used descriptive and inferential statistics. The findings revealed that both the municipality and the contractors contributed to the challenges experienced by citizens, with maintenance challenges being more serious than installation challenges. Municipal and political challenges were the main drivers, with political ownership of construction companies and political interference being the biggest problems. The findings contributed to a better understanding of the challenges inhibiting effective installation and maintenance of water infrastructure, and are important to the municipality, and the community at large, because they contribute to a better understanding of service delivery from the citizens’ perspectives

Ambient Gaseous Pollutants in an Urban Area in South Africa: Levels and Potential Human Health Risk

Urban air pollution from gaseous pollutants is a growing public health problem in many countries including South Africa. Examining the levels, trends and health risk of exposure to ambient gaseous pollutants will assist in understanding the effectiveness of existing control measures and plan for suitable management strategies. This study determined the concentration levels and non-cancer risk of CO, SO2, NO2, and O3 at an industrial area in Pretoria West, South Africa. We utilised a set of secondary data for CO, NO2, SO2, and O3 that was obtained from a monitoring station. Analysis of the hourly monitored data was done. Their non-cancer risk (HQ) was determined using the human health risk assessment model for different age categories. The annual levels of NO2 (39.442 &micro;g/m3), SO2 (22.464 &micro;g/m3), CO (722.003 &micro;g/m3) and the 8-hour concentration of CO (649.902 &micro;g/m3) and O3 (33.556 &micro;g/m3) did not exceed the South African National Ambient Air Quality Standards for each pollutant. The HQ for each pollutant across exposed groups (except children) was less than 1. This indicates that the recorded levels could not pose non-cancer risk to susceptible individuals