134 research outputs found

    Photosynthetic adaptation of two semi-arid species of Gethyllis (Kukumakranka) to drought-and-shade stress

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    Gethyllis multifolia and Gethyllis villosa are winter-growing, summer-blooming, deciduous and bulbous geophytes that grow naturally in the semi-arid ‘Succulent Karoo Biome’ of South Africa. G. multifolia is threatened in its natural habitat and resides in the ‘Vulnerable’ category of the ‘Red Data List of Southern African Plants’. Previous investigations suggested that G. multifolia is more sensitive to drought stress than G. villosa and that both species adopted certain morphological changes in their leaves during shade stress. Current models indicate that this biome is being exposed to increasingly drier conditions and shading from encroaching indigenous plant species. In this study, the photosynthetic gas exchange responses of both species to drought and shade stresses were investigated and the ‘Vulnerable’ conservation status of G. multifolia. This investigation found that during drought stress G. villosa had a more enhanced photosynthetic performance than G. multifolia which appears not to be related to foliar adaptations such as specific leaf mass (SLM), but to the G. villosa's leaves maintaining their stomatal conductance (Gs), photosynthetic light compensation (LCP) and photon yields. Furthermore, during shade stress G. villosa also had an improved photosynthetic performance by not altering its photosynthetic LCP during reduced light conditions. It can be concluded that G. multifolia has a lower capacity than G. villosa to adapt its photosynthetic apparatus to changing environments such as increasing drought and shaded conditions. This may be a contributing factor to the threatened conservation status of G. multifolia.Web of Scienc

    The Occurrence and Infectivity of Arbuscular Mycorrhizal Fungi in Inoculated and Uninoculated Rhizosphere Soils of Two-year-old Commercial Grapevines

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    Arbuscular mycorrhizal (AM) fungal populations present in the rhizosphere of vine roots in the vineyards of a commercial farm in the Stellenbosch Region were investigated using microscopic analyses. AM root colonisation levels of between 70% and 90% were found in both grapevine roots that were previously artificially inoculated with commercial AM inocula, and in uninoculated (control) grapevine roots. The AM fungal isolates in the rhizosphere soil, identified using morphological criteria, belonged to the genera Acaulospora, Gigaspora, Glomus, Sclerocystis and Scutellospora.  The majority of species found was not present in the commercial inocula and was either indigenous to the vineyard or originated from the nursery where the vines were obtained. Isolates of Glomus and Acaulospora appeared to be the most abundant. The AM fungal species occurred at a soil phosphorus (P) concentration of up to 80 mg/kg P and a soil pH (KCl) that ranged between 5.63 and 6.10. Total spore counts ranged between 1 000 and 3 779 spores/100 g dry soil. In accordance with literature, lower spore concentrations were recorded for the heavier soil types with no cover crop system, compared with the sandy soil type on which cover crops were sown annually

    SYSTEMS-2: a randomised phase II study of radiotherapy dose escalation for pain control in malignant pleural mesothelioma

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    SYSTEMS-2 is a randomised study of radiotherapy dose escalation for pain control in 112 patients with malignant pleural mesothelioma (MPM). Standard palliative (20Gy/5#) or dose escalated treatment (36Gy/6#) will be delivered using advanced radiotherapy techniques and pain responses will be compared at week 5. Data will guide optimal palliative radiotherapy in MPM

    Health economic implications of irbesartan plus conventional antihypertensive medications versus conventional blood pressure control alone in patients with type 2 diabetes, hypertension, and renal disease in Switzerland.

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    The aim of this health economic modelling study was to investigate the effect of irbesartan combined with conventional antihypertensive medications compared to conventional antihypertensive therapy alone on the progression of nephropathy in patients with hypertension, type 2 diabetes and microalbuminuria in a Swiss setting. In simulated patients with hypertension and type 2 diabetes, treatment of microalbuminuria with irbesartan 300 mg daily plus conventional antihypertensive medications was compared to a control regimen (conventional medications excluding angiotensin converting enzyme inhibitors, other angiotensin-2-receptor antagonist and dihydropyridine calcium channel blockers). Progression from microalbuminuria to nephropathy, doubling of serum creatinine, ESRD, and all-cause mortality was simulated over a 25-year time horizon using a published Markov model adapted to a Swiss setting. Transition probabilities were based on the Irbesartan in Reduction of Microalbuminuria-2 Study, Irbesartan in Diabetic Nephropathy Trial and other sources. Costs and clinical outcomes were discounted at 5% annually according to Swiss guidelines, and a third party payer perspective was taken. Treatment with irbesartan was projected to improve mean life expectancy by 0.57 years compared to conventional antihypertension treatment (undiscounted 1.22 years). Irbesartan treatment was associated with cost savings of CHF 21,488 per patient over the 25-year time horizon. Sensitivity analysis showed that irbesartan therapy remained dominant to conventional antihypertension treatment over a range of plausible assumptions. Addition of irbesartan to conventional antihypertension therapy was projected to improve life expectancy and reduce costs in hypertensive patients with type 2 diabetes and microalbuminuria in a Swiss setting

    Femtosecond Yb:YCOB laser pumped by narrow-stripe laser diode and passively modelocked using ion implanted saturable-absorber mirror

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    The authors present, what they believe to be, the first femtosecond Yb:YCOB laser, pumped by a low-power, narrow-stripe laser diode. To facilitate modelocking, high-energy oxygen ion implantation of the saturable absorber is employed. 210 fs pulse generation at 16 mW average output power for 140 mW incident pump power is reporte

    Action on the social determinants for advancing health equity in the time of COVID-19: perspectives of actors engaged in a WHO Special Initiative.

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    Since the 2008 publication of the reports of the Commission on Social Determinants of Health and its nine knowledge networks, substantial research has been undertaken to document and describe health inequities. The COVID-19 pandemic has underscored the need for a deeper understanding of, and broader action on, the social determinants of health. Building on this unique and critical opportunity, the World Health Organization is steering a multi-country Initiative to reduce health inequities through an action-learning process in 'Pathfinder' countries. The Initiative aims to develop replicable and reliable models and practices that can be adopted by WHO offices and UN staff to address the social determinants of health to advance health equity. This paper provides an overview of the Initiative by describing its broad theory of change and work undertaken in three regions and six Pathfinder countries in its first year-and-a-half. Participants engaged in the Initiative describe results of early country dialogues and promising entry points for implementation that involve model, network and capacity building. The insights communicated through this note from the field will be of interest for others aiming to advance health equity through taking action on the social determinants of health, in particular as regards structural determinants

    Computer modeling of diabetes and Its transparency: a report on the Eighth Mount Hood Challenge

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    Objectives The Eighth Mount Hood Challenge (held in St. Gallen, Switzerland, in September 2016) evaluated the transparency of model input documentation from two published health economics studies and developed guidelines for improving transparency in the reporting of input data underlying model-based economic analyses in diabetes. Methods Participating modeling groups were asked to reproduce the results of two published studies using the input data described in those articles. Gaps in input data were filled with assumptions reported by the modeling groups. Goodness of fit between the results reported in the target studies and the groups’ replicated outputs was evaluated using the slope of linear regression line and the coefficient of determination (R2). After a general discussion of the results, a diabetes-specific checklist for the transparency of model input was developed. Results Seven groups participated in the transparency challenge. The reporting of key model input parameters in the two studies, including the baseline characteristics of simulated patients, treatment effect and treatment intensification threshold assumptions, treatment effect evolution, prediction of complications and costs data, was inadequately transparent (and often missing altogether). Not surprisingly, goodness of fit was better for the study that reported its input data with more transparency. To improve the transparency in diabetes modeling, the Diabetes Modeling Input Checklist listing the minimal input data required for reproducibility in most diabetes modeling applications was developed. Conclusions Transparency of diabetes model inputs is important to the reproducibility and credibility of simulation results. In the Eighth Mount Hood Challenge, the Diabetes Modeling Input Checklist was developed with the goal of improving the transparency of input data reporting and reproducibility of diabetes simulation model results

    The Generationing of Power: A Comparison of Child-Parent and Sibling Relations in Scotland

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    The paper concentrates on an exploration of power relations within families. The paper discusses parental power in relation to legitimacy, household resources and children’s anticipated reactions of adult discipline. The nature of sibling power is highlighted before exploring the reciprocal expectations of sibling and child-parent interactions. The paper ends by suggesting that the generationing of power relations can lead to differing degrees of backstage and frontstage performances within the home
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