68 research outputs found

    Identifying key drivers of the impact of an HIV cure intervention in sub-Saharan Africa

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    BACKGROUND:  The properties required of an intervention that results in eradication or control of HIV in absence of antiretroviral therapy (ART-free viral suppression) to make it cost-effective in low income settings are unknown. METHODS:  We used a model of HIV and ART to investigate the effect of introducing an ART-free viral suppression intervention in 2022 in an example country of Zimbabwe. We assumed that the intervention (cost: 500)wouldbeaccessiblefor90500) would be accessible for 90% of the population, be given to those on effective ART, have sufficient efficacy to allow ART interruption in 95%, with a rate of viral rebound 5% per year in the first three months, and a 50% decline in rate with each successive year. RESULTS:  An ART-free viral suppression intervention with these properties would result in over 0.53 million disability-adjusted-life-years averted over 2022-2042, with a reduction in HIV programme costs of 300 million (8.7% saving). An intervention of this efficacy costing anything up to $1400 is likely to be cost-effective in this setting. CONCLUSION:  Interventions aimed at curing HIV have the potential to improve overall disease burden and to reduce costs. Given the effectiveness and cost of ART, such interventions would have to be inexpensive and highly effective

    Invasive Plant Suppresses the Growth of Native Tree Seedlings by Disrupting Belowground Mutualisms

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    The impact of exotic species on native organisms is widely acknowledged, but poorly understood. Very few studies have empirically investigated how invading plants may alter delicate ecological interactions among resident species in the invaded range. We present novel evidence that antifungal phytochemistry of the invasive plant, Alliaria petiolata, a European invader of North American forests, suppresses native plant growth by disrupting mutualistic associations between native canopy tree seedlings and belowground arbuscular mycorrhizal fungi. Our results elucidate an indirect mechanism by which invasive plants can impact native flora, and may help explain how this plant successfully invades relatively undisturbed forest habitat

    Robot Assisted Training for the Upper Limb after Stroke (RATULS): study protocol for a randomised controlled trial.

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    BACKGROUND: Loss of arm function is a common and distressing consequence of stroke. We describe the protocol for a pragmatic, multicentre randomised controlled trial to determine whether robot-assisted training improves upper limb function following stroke. METHODS/DESIGN: Study design: a pragmatic, three-arm, multicentre randomised controlled trial, economic analysis and process evaluation. SETTING: NHS stroke services. PARTICIPANTS: adults with acute or chronic first-ever stroke (1 week to 5 years post stroke) causing moderate to severe upper limb functional limitation. Randomisation groups: 1. Robot-assisted training using the InMotion robotic gym system for 45 min, three times/week for 12 weeks 2. Enhanced upper limb therapy for 45 min, three times/week for 12 weeks 3. Usual NHS care in accordance with local clinical practice Randomisation: individual participant randomisation stratified by centre, time since stroke, and severity of upper limb impairment. PRIMARY OUTCOME: upper limb function measured by the Action Research Arm Test (ARAT) at 3 months post randomisation. SECONDARY OUTCOMES: upper limb impairment (Fugl-Meyer Test), activities of daily living (Barthel ADL Index), quality of life (Stroke Impact Scale, EQ-5D-5L), resource use, cost per quality-adjusted life year and adverse events, at 3 and 6 months. Blinding: outcomes are undertaken by blinded assessors. Economic analysis: micro-costing and economic evaluation of interventions compared to usual NHS care. A within-trial analysis, with an economic model will be used to extrapolate longer-term costs and outcomes. Process evaluation: semi-structured interviews with participants and professionals to seek their views and experiences of the rehabilitation that they have received or provided, and factors affecting the implementation of the trial. SAMPLE SIZE: allowing for 10% attrition, 720 participants provide 80% power to detect a 15% difference in successful outcome between each of the treatment pairs. Successful outcome definition: baseline ARAT 0-7 must improve by 3 or more points; baseline ARAT 8-13 improve by 4 or more points; baseline ARAT 14-19 improve by 5 or more points; baseline ARAT 20-39 improve by 6 or more points. DISCUSSION: The results from this trial will determine whether robot-assisted training improves upper limb function post stroke. TRIAL REGISTRATION: ISRCTN, identifier: ISRCTN69371850 . Registered 4 October 2013

    Global change effects on plant communities are magnified by time and the number of global change factors imposed

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    Global change drivers (GCDs) are expected to alter community structure and consequently, the services that ecosystems provide. Yet, few experimental investigations have examined effects of GCDs on plant community structure across multiple ecosystem types, and those that do exist present conflicting patterns. In an unprecedented global synthesis of over 100 experiments that manipulated factors linked to GCDs, we show that herbaceous plant community responses depend on experimental manipulation length and number of factors manipulated. We found that plant communities are fairly resistant to experimentally manipulated GCDs in the short term (<10 y). In contrast, long-term (≥10 y) experiments show increasing community divergence of treatments from control conditions. Surprisingly, these community responses occurred with similar frequency across the GCD types manipulated in our database. However, community responses were more common when 3 or more GCDs were simultaneously manipulated, suggesting the emergence of additive or synergistic effects of multiple drivers, particularly over long time periods. In half of the cases, GCD manipulations caused a difference in community composition without a corresponding species richness difference, indicating that species reordering or replacement is an important mechanism of community responses to GCDs and should be given greater consideration when examining consequences of GCDs for the biodiversity–ecosystem function relationship. Human activities are currently driving unparalleled global changes worldwide. Our analyses provide the most comprehensive evidence to date that these human activities may have widespread impacts on plant community composition globally, which will increase in frequency over time and be greater in areas where communities face multiple GCDs simultaneously

    Market Barriers Faced by Formal and Informal Vendors of African Leafy Vegetables in Western Kenya

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    This research investigated market barriers faced by formal and informal vendors of traditional vegetables in Kenya, with the goal of closing market gaps and improving consumer access. The most common problem was access to capital, but informal vendors were more likely than formal vendors to perceive this as a major problem. Overall, 97% of vendors said that they had seen the vegetable market grow, which suggests that this market is still expanding. To improve urban nutritional security, the most important changes policymakers could enact are to increase access to capital and improve infrastructure to connect rural growers with urban consumers

    Characterization of sporulation of Alternaria alternata f. sp. sphenocleae

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    Studies were conducted on agar media to characterize the factors for the optimization of sporulation of Alternaria alternata f. sp. sphenocleae, a fungal pathogen being evaluated as a biological control agent for Sphenoclea zeylanica (gooseweed). A. alternata f. sp. sphenocleae conidiation was affected by nutrition, temperature, light conditions, and moisture. On all agar media tested, except for half-strength potato dextrose agar ( 1/2 PDA) and V-8 juice agar (VJA), exposure to different light conditions did not have any significant effect on conidia production. However, when comparing 1/2 PDA and VJA, sporulation under constant near-ultraviolet (NUV) light at 28°C increased markedly on VJA, but decreased substantially on 1/2 PDA. This trend, however, was opposite under dark conditions since 1/2 PDA produced the greatest number of conidia whereas a 75% reduction in conidia production occurred on VJA in the dark. On all the standard agar media evaluated, the most virulent conidia were obtained on 1/2 PDA at 28°C under constant NUV incubated for 4 weeks. Sporulation of A. alternata f. sp. sphenocleae using the sporulation medium (S-medium) technique was rapid. Conidia were produced within 24 h and continuous sporulation was still observed until 120 h. The best primary agar media for conidia production were PDA, 1/2 PDA and VJA, while water agar was the poorest. Conidia production was optimized with the addition of 20 g l of calcium carbonate (CaCO) and the addition of 2 ml of sterile distilled water on the medium. The most virulent conidia were produced when the primary agar was 1/2 PDA, the CaCO concentration was 20 g l, and the cultures were incubated at 18°C in the dark. Conidiophore induction occurred on nutrient rich media and was stimulated by NUV, while formation of conidia proceeded in darkness after nutrients were depleted under warm dry or cool moist conditions. Culture media, growth conditions, and CaCO affected the inoculum potential of A. alternata f. sp. sphenocleae conidia
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