91 research outputs found

    Deglacial landform assemblage records fast ice-flow and retreat, Inner Hebrides, Scotland

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    High-resolution bathymetric data have been central to recent advances in the understanding of past dynamics of the former British–Irish Ice Sheet (BIIS). As approximately two-thirds of the former BIIS was probably marine-based during the Last Glacial Maximum (LGM) (c. 29–23 ka), geomorphic observations of the seabed are required increasingly to understand the extent, pattern and timing of past glaciation. Until recently, glacial reconstructions for the Inner Hebrides, offshore of western Scotland, have been based primarily on terrestrial observations. Previous workers have proposed generalized reconstructions in which the Inner Hebrides are located within a significant former ice-sheet flow pathway that drained the western Scottish sector of the BIIS, feeding the Barra Fan during the LGM and earlier glaciations (Fig. 1). Results from numerical ice-sheet modelling suggest that former ice-flow velocities within the region were on the order of hundreds to thousands of metres per year, but yield further insight by demonstrating how dynamic binge/purge cycles may have affected ice-sheet mass balance over time (Hubbard et al. 2009). Following the LGM, ice-sheet retreat through the area is estimated to have been in the order of 20 m per year (Clark et al. 2012). Here we present swath-bathymetric data from the Inner Hebrides that provide in situ constraints on ice-sheet flow and subsequent retreat dynamics from within this important sector of the BIIS

    Prediction Model Development and Validation of 12-Year Incident Edentulism of Older Adults in the United States

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    Introduction: Edentulism affects health and quality of life. Objectives: Identify factors that predict older adults becoming edentulous over 12 y in the US Health and Retirement Study (HRS) by developing and validating a prediction model. Methods: The HRS includes data on a representative sample of US adults aged >50 y. Selection criteria included participants in 2006 and 2018 who answered, "Have you lost all of your upper and lower natural permanent teeth" Persons who answered "no" in 2006 and "yes" in 2018 experienced incident edentulism. Excluding 2006 edentulous, the data set (n = 4,288) was split into selection (70%, n = 3,002) and test data (30%, n = 1,286), and Monte Carlo cross-validation was applied to 500 random partitions of the selection data into training (n = 1,716) and validation (n = 1,286) data sets. Fitted logistic models from the training data sets were applied to the validation data sets to obtain area under the curve (AUC) for 32 candidate models. Six variables were included in all models (age, race/ethnicity, gender, education, smoking, last dental visit) while all combinations of 5 variables (income, alcohol use, self-rated health, loneliness, cognitive status) were considered for inclusion. The best parsimonious model based on highest mean AUC was fitted to the selection data set to obtain a final prediction equation. It was applied to the test data to estimate AUC and 95% confidence interval using 1,000 bootstrap samples. Results: From 2006 to 2018, 9.7% of older adults became edentulous. The 2006 mean (SD) age was 66.7 (8.7) for newly edentulous and 66.3 (8.4) for dentate (P = 0.31). The baseline 6-variable model mean AUC was 0.740. The 7-variable model with cognition had AUC = 0.749 and test data AUC = 0.748 (95% confidence interval, 0.715?0.781), modestly improving prediction. Negligible improvement was gained from adding more variables.Conclusion:Cognition information improved the 12-y prediction of becoming edentulous beyond the modifiable risk factors of smoking and dental care use, as well as nonmodifiable demographic factors.Knowledge Transfer Statement:This prediction modeling and validation study identifies cognition as well as modifiable (dental care use, smoking) and nonmodifiable factors (race, ethnicity, gender, age, education) associated with incident complete tooth loss in the United States. This information is useful for the public, dental care providers, and health policy makers in improving approaches to preventive care, oral and general health, and quality of life for older adults

    Ramsar Wetlands of International Importance–improving conservation outcomes

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    The Ramsar Convention (or the Convention on Wetlands), signed in 1971, was one of the first international conservation agreements, promoting global wise use of wetlands. It has three primary objectives: national designation and management of wetlands of international importance; general wise use of wetlands; and international cooperation. We examined lessons learnt for improving wetland conservation after Ramsar’s nearly five decades of operation. The number of wetlands in the Ramsar Site Network has grown over time (2,391 Ramsar Sites, 2.5 million km2, as at 2020-06-09) but unevenly around the world, with decreasing rate of growth in recent decades. Ramsar Sites are concentrated in countries with a high Gross Domestic Product and human pressure (e.g., western Europe) but, in contrast, Ramsar Sites with the largest wetland extent are in central-west Africa and South America. We identified three key challenges for improving effectiveness of the Ramsar Site Network: increasing number of sites and wetland area, improved representation (functional, geographical and biological); and effective management and reporting. Increasing the number of sites and area in the Ramsar network could benefit from targets, implemented at national scales. Knowledge of representativeness is inadequate, requiring analyses of functional ecotypes, geographical and biological representativeness. Finally, most countries have inadequate management planning and reporting on the ecological character of their Ramsar Sites, requiring more focused attention on a vision and objectives, with regular reporting of key indicators to guide management. There are increasing opportunities to rigorously track ecological character, utilizing new tools and available indicators (e.g., remote sensing). It is critical that the world protect its wetlands, with an effective Ramsar Convention or the Convention on Wetlands at the core

    Impact of acute consumption of beverages containing plant-based or alternative sweetener blends on postprandial appetite, food intake, metabolism, and gastro-intestinal symptoms: Results of the SWEET beverages trial

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    Project SWEET examined the barriers and facilitators to the use of non-nutritive sweeteners and sweetness enhancers (hereafter "S&SE") alongside potential risks/benefits for health and sustainability. The Beverages trial was a double-blind multi-centre, randomised crossover trial within SWEET evaluating the acute impact of three S&SE blends (plant-based and alternatives) vs. a sucrose control on glycaemic response, food intake, appetite sensations and safety after a carbohydrate-rich breakfast meal. The blends were: mogroside V and stevia RebM; stevia RebA and thaumatin; and sucralose and acesulfame-potassium (ace-K). At each 4 h visit, 60 healthy volunteers (53% male; all with overweight/obesity) consumed a 330 mL beverage with either an S&SE blend (0 kJ) or 8% sucrose (26 g, 442 kJ), shortly followed by a standardised breakfast (∼2600 or 1800 kJ with 77 or 51 g carbohydrates, depending on sex). All blends reduced the 2-h incremental area-under-the-curve (iAUC) for blood insulin (p 0.05 for all). Compared with sucrose, there was a 3% increase in LDL-cholesterol after stevia RebA-thaumatin (p < 0.001 in adjusted models); and a 2% decrease in HDL-cholesterol after sucralose-ace-K (p < 0.01). There was an impact of blend on fullness and desire to eat ratings (both p < 0.05) and sucralose-acesulfame K induced higher prospective intake vs sucrose (p < 0.001 in adjusted models), but changes were of a small magnitude and did not translate into energy intake differences over the next 24 h. Gastro-intestinal symptoms for all beverages were mostly mild. In general, responses to a carbohydrate-rich meal following consumption of S&SE blends with stevia or sucralose were similar to sucrose

    Mineralogical Transformations and Soil Development in Shale Across a Latitudinal Climosequence

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    To investigate factors controlling soil formation, we established a climosequence as part of the Susquehanna-Shale Hills Critical Zone Observatory (SSHCZO) in central Pennsylvania, USA. Sites were located on organic matter-poor, iron-rich Silurian-aged shale in Wales, Pennsylvania, Virginia, Tennessee, Alabama, and Puerto Rico, although this last site is underlain by a younger shale. Across the climosequence, mean annual temperature (MAT) increases from 7 to 24°C and mean annual precipitation (MAP) ranges from 100 to 250 cm. Variations in soil characteristics along the climosequence, including depth, morphology, particle-size distribution, geochemistry, and bulk and clay mineralogy, were characterized to investigate the role of climate in controlling mineral transformations and soil formation. Overall, soil horizonation, depth, clay content, and chemical depletion increase with increasing temperature and precipitation, consistent with enhanced soil development and weathering processes in warmer and wetter locations. Secondary minerals are present at higher concentrations at the warmest sites of the climosequence; kaolinite increases from \u3c5% at northern sites in Wales and Pennsylvania to 30% in Puerto Rico. The deepest observed weathering reaction is plagioclase feldspar dissolution followed by the transformation of chlorite and illite to vermiculite and hydroxy-interlayered vermiculite. Plagioclase, although constituting \u3c12% of the initial shale mineralogy, may be the profile initiating reaction that begins shale bedrock transformation to weathered regolith. Weathering of the more abundant chlorite and illite minerals (∼70% of initial mineralogy), however, are more likely controlling regolith thickness. Climate appears to play a central role in driving soil formation and mineral weathering reactions across the climosequence

    Global CO2 emissions from dry inland waters share common drivers across ecosystems

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    Many inland waters exhibit complete or partial desiccation, or have vanished due to global change, exposing sediments to the atmosphere. Yet, data on carbon dioxide (CO2) emissions from these sediments are too scarce to upscale emissions for global estimates or to understand their fundamental drivers. Here, we present the results of a global survey covering 196 dry inland waters across diverse ecosystem types and climate zones. We show that their CO2 emissions share fundamental drivers and constitute a substantial fraction of the carbon cycled by inland waters. CO2 emissions were consistent across ecosystem types and climate zones, with local characteristics explaining much of the variability. Accounting for such emissions increases global estimates of carbon emissions from inland waters by 6% (~0.12 Pg C y−1). Our results indicate that emissions from dry inland waters represent a significant and likely increasing component of the inland waters carbon cycle

    High pressure CVD inside microstructured optical fibres

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    We report the fabrication of semiconductor structures within holey fibres via a pressure driven microfluidic chemical vapour deposition process, demonstrating templated growth of crystalline Group IV semiconductor structures and devices in extreme aspect ratio geometries

    WHO global research priorities for antimicrobial resistance in human health

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    The WHO research agenda for antimicrobial resistance (AMR) in human health has identified 40 research priorities to be addressed by the year 2030. These priorities focus on bacterial and fungal pathogens of crucial importance in addressing AMR, including drug-resistant pathogens causing tuberculosis. These research priorities encompass the entire people-centred journey, covering prevention, diagnosis, and treatment of antimicrobial-resistant infections, in addition to addressing the overarching knowledge gaps in AMR epidemiology, burden and drivers, policies and regulations, and awareness and education. The research priorities were identified through a multistage process, starting with a comprehensive scoping review of knowledge gaps, with expert inputs gathered through a survey and open call. The priority setting involved a rigorous modified Child Health and Nutrition Research Initiative approach, ensuring global representation and applicability of the findings. The ultimate goal of this research agenda is to encourage research and investment in the generation of evidence to better understand AMR dynamics and facilitate policy translation for reducing the burden and consequences of AMR

    Highly efficient blue photoluminescence from colloidal lead-iodide nanoparticles

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    We report the synthesis of solvent-stabilized lead-iodide nanoparticles, using a convenient route involving coordinating solvents. The resultant colloids show strong absorption features in the ultraviolet region of the optical spectrum, which are consistent with the formation of semiconducting nanocrystals of lead (II) iodide. An effective-mass approximation model of quantum-confined states is in good agreement with the observed transition energies, giving strong indications of the particle morphologies and dimensions. Intense photoluminescence is also observed, with some spectral tuning possible with ripening time, giving a range of emission photon energies approximately spanning from 2.5 to 3.0 eV. We measure photo-stable luminescence quantum efficiencies of around 20% in solution, increasing to up to 30% if the coordinating ligand is exchanged for a Lewis-base capping layer. This demonstrates the potential for the utilization of lead-iodide nanocrystals in visible optoelectronics applications
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