169 research outputs found

    An Innovative 3D Ultrasonic Actuator with Multidegree of Freedom for Machine Vision and Robot Guidance Industrial Applications Using A Single Vibration Ring Transducer

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    This paper presents an innovative 3D piezoelectric ultrasonic actuator using a single flexural vibration ring transducer, for machine vision and robot guidance industrial applications. The proposed actuator is principally aiming to overcome the visual spotlight focus angle of digital visual data capture transducer, digital cameras and enhance the machine vision system ability to perceive and move in 3D. The actuator Design, structures, working principles and finite element analysis are discussed in this paper. A prototype of the actuator was fabricated. Experimental tests and measurements showed the ability of the developed prototype to provide 3D motions of Multidegree of freedom, with typical speed of movement equal to 35 revolutions per minute, a resolution of less than 5μm and maximum load of 3.5 Newton. These initial characteristics illustrate, the potential of the developed 3D micro actuator to gear the spotlight focus angle issue of digital visual data capture transducers and possible improvement that such technology could bring to the machine vision and robot guidance industrial applications

    Causal Pathways from Enteropathogens to Environmental Enteropathy: Findings from the MAL-ED Birth Cohort Study

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    Background Environmental enteropathy (EE), the adverse impact of frequent and numerous enteric infections on the gut resulting in a state of persistent immune activation and altered permeability, has been proposed as a key determinant of growth failure in children in low- and middle-income populations. A theory-driven systems model to critically evaluate pathways through which enteropathogens, gut permeability, and intestinal and systemic inflammation affect child growth was conducted within the framework of the Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) birth cohort study that included children from eight countries. Methods Non-diarrheal stool samples (N = 22,846) from 1253 children from multiple sites were evaluated for a panel of 40 enteropathogens and fecal concentrations of myeloperoxidase, alpha-1-antitrypsin, and neopterin. Among these same children, urinary lactulose:mannitol (L:M) (N = 6363) and plasma alpha-1-acid glycoprotein (AGP) (N = 2797) were also measured. The temporal sampling design was used to create a directed acyclic graph of proposed mechanistic pathways between enteropathogen detection in non-diarrheal stools, biomarkers of intestinal permeability and inflammation, systemic inflammation and change in length- and weight- for age in children 0–2 years of age. Findings Children in these populations had frequent enteric infections and high levels of both intestinal and systemic inflammation. Higher burdens of enteropathogens, especially those categorized as being enteroinvasive or causing mucosal disruption, were associated with elevated biomarker concentrations of gut and systemic inflammation and, via these associations, indirectly associated with both reduced linear and ponderal growth. Evidence for the association with reduced linear growth was stronger for systemic inflammation than for gut inflammation; the opposite was true of reduced ponderal growth. Although Giardia was associated with reduced growth, the association was not mediated by any of the biomarkers evaluated. Interpretation The large quantity of empirical evidence contributing to this analysis supports the conceptual model of EE. The effects of EE on growth faltering in young children were small, but multiple mechanistic pathways underlying the attribution of growth failure to asymptomatic enteric infections had statistical support in the analysis. The strongest evidence for EE was the association between enteropathogens and linear growth mediated through systemic inflammation

    Community-led monitoring and the role of Ritshidze in improving the quality of primary healthcare in South Africa

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    Community-led monitoring (CLM) of health services is a mechanism of community participation and accountability that is increasingly advocated across the globe. In South Africa (SA), a large-scale community-led monitoring initiative called Ritshidze (‘saving our lives’) was established in 2019. Steered by a coalition of civil society organisations representing people living with HIV, Ritshidze monitors just over 400 primary healthcare (PHC) facilities in 8 provinces on a quarterly basis. In this piece we describe the purposes and design features and the five-step approach to CLM of the Ritshidze model. We also highlight some of the positive changes achieved, and reflect on possible reasons for successes. In doing so, we aim to draw attention to this significant national initiative and its potential as a mechanism of social accountability in SA

    Micro Doses, Mega Benefits Promoting Fertilizer Use in Semi-Arid Zimbabwe

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    The contents of this document are (1) soil fertility and crop production in the smallholder systems, (2) current knowledge about fertilizer use in the dry areas of Zimbabwe, (3) low Input Options – microdosing, (4) what is microdosing? (5) types of N fertilizer available in Zimbabwe, (6) evidence of success from the drier areas of Zimbabwe, (7) how much fertilizer should a farmer buy? (8) where and how can farmers get fertilizer? (9) how sustainable is microdosing? (10) how can farmers maximize returns on their investment in fertility amendments? (11) introducing and Promoting Microdosing to Smallholder farmers, (12) training farmers in microdosing and (13) setting up demonstrations on microdosing

    Binding of SGTA to Rpn13 selectively modulates protein quality control

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    YesRpn13 is an intrinsic ubiquitin receptor of the 26S proteasome regulatory subunit that facilitates substrate capture prior to degradation. Here we show that the C-terminal region of Rpn13 binds to the tetratricopeptide repeat (TPR) domain of SGTA, a cytosolic factor implicated in the quality control of mislocalised membrane proteins (MLPs). The overexpression of SGTA results in a substantial increase in steady-state MLP levels, consistent with an effect on proteasomal degradation. However, this effect is strongly dependent upon the interaction of SGTA with the proteasomal component Rpn13. Hence, overexpression of the SGTA-binding region of Rpn13 or point mutations within the SGTA TPR domain both inhibit SGTA binding to the proteasome and substantially reduce MLP levels. These findings suggest that SGTA can regulate the access of MLPs to the proteolytic core of the proteasome, implying that a protein quality control cycle that involves SGTA and the BAG6 complex can operate at the 19S regulatory particle. We speculate that the binding of SGTA to Rpn13 enables specific polypeptides to escape proteasomal degradation and/or selectively modulates substrate degradation.BBSRC [grant number: BB/L006510/1] and the Wellcome Trust [grant number: 092107/Z/10/Z]. K.K. was supported by the UPStream network [EU, FP7, ITN project 290257

    Yield and growth of different amaranth genotypes under varying water regimes

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    Traditional vegetables are piloted as champion species for sub-Saharan Africa, a region experiencing high nutritional food insecurity and water scarcity. Amaranth is one of the traditional vegetables that has excellent potential to be commercialized in South Africa. The study's main objective was to assess the effect of different water regimes on six amaranth genotypes that were used to generate a MAGIC population as well as two reference genotypes. An experiment was conducted under rain shelters at ARC-VIMP, Roodeplaat Pretoria, Gauteng, during the 2020/2021 and 2021/2022 summer seasons. The experiment was laid out in a 3×4 factorial treatment in a completely randomized design with amaranth genotypes (VI060472, VI061494, VI044371, VI062433, VI061487, VI050446, 'Arusha' and 'Anna',) and water levels (20-25% (W1), 60-65% (W2), and 80-85% (W3)), replicated three times, of each genotype/water level combination. Data collected included total fresh and dry biomass, total fresh and dry leaf mass (t ha-1), leaf number, fresh and dry leaf mass in g plant-1 and initial and final plant height. The study's findings showed that there was a highly significant difference as well as an interaction effect for water levels and genotypes for the selected variables. Total dry biomass ranged from 32.93 to 61.36 t ha-1, and dry leaf mass per plant from 6.43 to 18.35 g. Higher productivity was observed from the VI061494 genotype. Therefore, this genotype can be recommended to farmers who want to commercialize amaranth; they will attain higher productivity, assuming that agronomic management is the same

    Perceptions of and practical experience with the National Surveillance Centre in managing medicines availability amongst users within public healthcare facilities in South Africa : findings and implications

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    The introduction of the National Surveillance Centre (NSC) has improved the efficiency and effectiveness of managing medicines availability within the public healthcare system in South Africa. However, at present, there is limited data regarding the perceptions among users of the NSC and challenges that need addressing. A descriptive quantitative study was performed among all registered active NSC users between August and November 2022. Overall, 114/169 users responded to a custom-developed, self-administered questionnaire (67.5% response rate). Most respondents used the Stock Visibility System (SVS) National Department of Health (NDoH) (66.7% for medicines and 51.8% for personal protective equipment (PPE) or SVS COVID-19 (64.9% for COVID-19 vaccines) or RxSolution (57.0% manual report or 42.1% application programming interface (API)) for reporting medicines, PPE, and COVID-19 vaccines to the NSC and were confident in the accuracy of the reported data. Most respondents focused on both medicines availability and reporting compliance when accessing the NSC, with the integrated medicines availability dashboard and the COVID-19 vaccine dashboard being the most popular. The respondents believed the NSC allowed ease of access to data and improved data quality to better monitor medicines availability and use. Identified areas for improvement included improving internet connectivity, retraining some users, standardising the dashboards, adding more data points and reports, and expanding user adoption by increasing licence limits. Overall, this study found that the NSC in South Africa provides an effective solution for monitoring and improving medicines availability

    Early-childhood linear growth faltering in low- and middle-income countries

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    Globally, 149 million children under 5 years of age are estimated to be stunted (length more than 2 standard deviations below international growth standards) 1,2. Stunting, a form of linear growth faltering, increases the risk of illness, impaired cognitive development and mortality. Global stunting estimates rely on cross-sectional surveys, which cannot provide direct information about the timing of onset or persistence of growth faltering—a key consideration for defining critical windows to deliver preventive interventions. Here we completed a pooled analysis of longitudinal studies in low- and middle-income countries (n = 32 cohorts, 52,640 children, ages 0–24 months), allowing us to identify the typical age of onset of linear growth faltering and to investigate recurrent faltering in early life. The highest incidence of stunting onset occurred from birth to the age of 3 months, with substantially higher stunting at birth in South Asia. From 0 to 15 months, stunting reversal was rare; children who reversed their stunting status frequently relapsed, and relapse rates were substantially higher among children born stunted. Early onset and low reversal rates suggest that improving children’s linear growth will require life course interventions for women of childbearing age and a greater emphasis on interventions for children under 6 months of age

    Child wasting and concurrent stunting in low- and middle-income countries

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    Sustainable Development Goal 2.2—to end malnutrition by 2030—includes the elimination of child wasting, defined as a weight-for-length z-score that is more than two standard deviations below the median of the World Health Organization standards for child growth 1. Prevailing methods to measure wasting rely on cross-sectional surveys that cannot measure onset, recovery and persistence—key features that inform preventive interventions and estimates of disease burden. Here we analyse 21 longitudinal cohorts and show that wasting is a highly dynamic process of onset and recovery, with incidence peaking between birth and 3 months. Many more children experience an episode of wasting at some point during their first 24 months than prevalent cases at a single point in time suggest. For example, at the age of 24 months, 5.6% of children were wasted, but by the same age (24 months), 29.2% of children had experienced at least one wasting episode and 10.0% had experienced two or more episodes. Children who were wasted before the age of 6 months had a faster recovery and shorter episodes than did children who were wasted at older ages; however, early wasting increased the risk of later growth faltering, including concurrent wasting and stunting (low length-for-age z-score), and thus increased the risk of mortality. In diverse populations with high seasonal rainfall, the population average weight-for-length z-score varied substantially (more than 0.5 z in some cohorts), with the lowest mean z-scores occurring during the rainiest months; this indicates that seasonally targeted interventions could be considered. Our results show the importance of establishing interventions to prevent wasting from birth to the age of 6 months, probably through improved maternal nutrition, to complement current programmes that focus on children aged 6–59 months
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