61 research outputs found

    Global Assessment of Agricultural System Redesign for Sustainable Intensification

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    The sustainable intensification (SI) of agricultural systems offers synergistic opportunities for the co31 production of agricultural and natural capital outcomes. Efficiency and Substitution are steps towards SI, but system Redesign is essential to deliver optimum outcomes as ecological and economic conditions change. We show global progress towards SI by farms and hectares, using seven SI sub-types: integrated pest management, conservation agriculture, integrated crop and biodiversity, pasture and forage, trees, irrigation management, and small/patch systems. From 47 SI initiatives at scale (each >104 farms or hectares), we estimate 163M farms (29% of all worldwide) have crossed a redesign threshold, practising forms of SI on 453Mha of agricultural land (9% of worldwide total). Key challenges include investing to integrate more forms of SI in farming systems, creating agricultural knowledge economies, and establishing policy measures to scale SI further. We conclude that SI may be approaching a tipping point where it could be transformative

    The Parker problem:existence of smooth force-free fields and coronal heating

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    Lifestyle changes and the risk of developing endometrial and ovarian cancers: opportunities for prevention and management

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    Anna L Beavis,1,* Anna Jo Bodurtha Smith,2,* Amanda Nickles Fader1 1Department of Gynecology and Obstetrics, The Kelly Gynecologic Oncology Service, Johns Hopkins Medicine, Baltimore, MD, 2Harvard Medical School, Boston, MA, USA *These authors contributed equally to this work Abstract: Modifiable lifestyle factors, such as obesity, lack of physical activity, and smoking, contribute greatly to cancer and chronic disease morbidity and mortality worldwide. This review appraises recent evidence on modifiable lifestyle factors in the prevention of endometrial cancer (EC) and ovarian cancer (OC) as well as new evidence for lifestyle management of EC and OC survivors. For EC, obesity continues to be the strongest risk factor, while new evidence suggests that physical activity, oral contraceptive pills, and bariatric surgery may be protective against EC. Other medications, such as metformin and nonsteroidal anti-inflammatory drugs, may be protective, and interventional research is ongoing. For OC, we find increasing evidence to support the hypothesis that obesity and hormone replacement therapy increase the risk of developing OC. Oral contraceptive pills are protective against OC but are underutilized. Dietary factors such as the Mediterranean diet and alcohol consumption do not seem to affect the risk of either OC or EC. For EC and OC survivors, physical activity and weight loss are associated with improved quality of life. Small interventional trials show promise in increasing physical activity and weight maintenance for EC and OC survivors, although the impact on long-term health, including cancer recurrence and overall mortality, is unknown. Women’s health providers should integrate counseling about these modifiable lifestyle factors into both the discussion of prevention for all women and the management of survivors of gynecologic cancers. Keywords: lifestyle, prevention, endometrial cancer, ovarian cancer, gynecologic cancer, obesit

    Manganese oxides, Earth surface oxygenation, and the rise of oxygenic photosynthesis

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    Oxygenic photosynthesis is arguably the most important biological innovation in Earth's history, facilitating the transition to a habitable planet for complex life. Dating the emergence of oxygenic photosynthesis, however, has proven difficult with estimates spanning a billion years. Sedimentary manganese (Mn) enrichments represent a potentially important line of evidence given the high redox potentials necessary to oxidize Mn in natural environments. However, this view has been challenged by abiotic and anaerobic Mn oxidation pathways that decouple Mn enrichments from oxygenation. With these in mind, we review Mn oxidation pathways and Mn enrichments and evaluate their relation to Earth's oxygenation. We argue that despite possible alternative pathways, shallow oxygenated seawater is a prerequisite for generating and, importantly, preserving significant sedimentary Mn enrichments (and associated geochemical signals). This implies that Mn enrichments indeed track Earth's oxygenation and oxygenic photosynthesis emerged 100 s of millions of years prior to irreversible atmospheric oxygenation
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