1,760 research outputs found

    Plasma deposition of constrained layer damping coatings

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    Plasma techniques are used to generate constrained layer damping (CLD) coatings on metallic substrates. The process involves the deposition of relatively thick, hard ceramic layers on to soft polymeric damping materials while maintaining the integrity of both layers. Reactive plasma sputter-deposition from an aluminium alloy target is used to deposit alumina layers, with Young's modulus in the range 77-220GPa and thickness up to 335 Ό, on top of a silicone film. This methodology is also used to deposit a 40 Ό alumina layer on a conventional viscoelastic damping film to produce an integral damping coating. Plasma CLD systems are shown to give at least 50 per cent more damping than equivalent metal-foil-based treatments. Numerical methods for rapid prediction of the performance of such coatings are discussed and validated by comparison with experimental results

    More salt, please:global patterns, responses, and impacts of foliar sodium in grasslands

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    Sodium is unique among abundant elemental nutrients, because most plant species do not require it for growth or development, whereas animals physiologically require sodium. Foliar sodium influences consumption rates by animals and can structure herbivores across landscapes. We quantified foliar sodium in 201 locally abundant, herbaceous species representing 32 families and, at 26 sites on four continents, experimentally manipulated vertebrate herbivores and elemental nutrients to determine their effect on foliar sodium. Foliar sodium varied taxonomically and geographically, spanning five orders of magnitude. Site‐level foliar sodium increased most strongly with site aridity and soil sodium; nutrient addition weakened the relationship between aridity and mean foliar sodium. Within sites, high sodium plants declined in abundance with fertilisation, whereas low sodium plants increased. Herbivory provided an explanation: herbivores selectively reduced high nutrient, high sodium plants. Thus, interactions among climate, nutrients and the resulting nutritional value for herbivores determine foliar sodium biogeography in herbaceous‐dominated systems

    Soil net nitrogen mineralisation across global grasslands

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    Soil nitrogen mineralisation (Nmin), the conversion of organic into inorganic N, is important for productivity and nutrient cycling. The balance between mineralisation and immobilisation (net Nmin) varies with soil properties and climate. However, because most global-scale assessments of net Nmin are laboratory-based, its regulation under field-conditions and implications for real-world soil functioning remain uncertain. Here, we explore the drivers of realised (field) and potential (laboratory) soil net Nmin across 30 grasslands worldwide. We find that realised Nmin is largely explained by temperature of the wettest quarter, microbial biomass, clay content and bulk density. Potential Nmin only weakly correlates with realised Nmin, but contributes to explain realised net Nmin when combined with soil and climatic variables. We provide novel insights of global realised soil net Nmin and show that potential soil net Nmin data available in the literature could be parameterised with soil and climate data to better predict realised Nmin

    Attention Deficit Hyperactivity Disorder: Is There an App for That? Suitability Assessment of Apps for Children and Young People With ADHD

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    Background: Attention-deficit/hyperactivity disorder (ADHD) is a complex highly comorbid disorder, which can have a huge impact on those with ADHD, their family, and the community around them. ADHD is currently managed using pharmacological and nonpharmacological interventions. However, with advances in technology and an increase in the use of mobile apps, managing ADHD can be augmented using apps specifically designed for this population. However, little is known regarding the suitability and usability of currently available apps. Objective: The aim of this study was to explore the suitability of the top 10 listed apps for children and young people with ADHD and clinicians who work with them. It is hypothesized that mobile apps designed for this population could be more suitably designed for this population. Methods: The top 10 listed apps that are specifically targeted toward children and young people with ADHD in the United Kingdom were identified via the Google Play (n=5) and iTunes store (n=5). Interviews were then undertaken with 5 clinicians who specialize in treating this population and 5 children and young people with ADHD themselves, to explore their opinions of the 10 apps identified and what they believe the key components are for apps to be suitable for this population. Results: Five themes emerged from clinician and young people interviews: the accessibility of the technology, the importance of relating to apps, addressing ADHD symptoms and related difficulties, age appropriateness, and app interaction. Three additional themes emerged from the clinician interviews alone: monitoring symptoms, side effects and app effect on relationships, and the impact of common comorbid conditions. The characteristics of the apps did not appear to match well with the views of our sample. Conclusions: These findings suggest that the apps may not be suitable in meeting the complex needs associated with this condition. Further research is required to explore the value of apps for children and young people with ADHD and their families and, in particular, any positive role for apps in the management of ADHD in this age group. A systematic review on how technology can be used to engage this population and how it can be used to help them would be a useful way forward. This could be the platform to begin exploring the use of apps further

    LV reverse remodeling imparted by aortic valve replacement for severe aortic stenosis; is it durable? A cardiovascular MRI study sponsored by the American Heart Association

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    <p>Abstract</p> <p>Background</p> <p>In patients with severe aortic stenosis (AS), long-term data tracking surgically induced effects of afterload reduction on reverse LV remodeling are not available. Echocardiographic data is available short term, but in limited fashion beyond one year. Cardiovascular MRI (CMR) offers the ability to serially track changes in LV metrics with small numbers due to its inherent high spatial resolution and low variability.</p> <p>Hypothesis</p> <p>We hypothesize that changes in LV structure and function following aortic valve replacement (AVR) are detectable by CMR and once triggered by AVR, continue for an extended period.</p> <p>Methods</p> <p>Tweny-four patients of which ten (67 ± 12 years, 6 female) with severe, but compensated AS underwent CMR pre-AVR, 6 months, 1 year and up to 4 years post-AVR. 3D LV mass index, volumetrics, LV geometry, and EF were measured.</p> <p>Results</p> <p>All patients survived AVR and underwent CMR 4 serial CMR's. LVMI markedly decreased by 6 months (157 ± 42 to 134 ± 32 g/m<sup><b>2</b></sup>, p < 0.005) and continued trending downwards through 4 years (127 ± 32 g/m<sup><b>2</b></sup>). Similarly, EF increased pre to post-AVR (55 ± 22 to 65 ± 11%,(p < 0.05)) and continued trending upwards, remaining stable through years 1-4 (66 ± 11 vs. 65 ± 9%). LVEDVI, initially high pre-AVR, decreased post-AVR (83 ± 30 to 68 ± 11 ml/m2, p < 0.05) trending even lower by year 4 (66 ± 10 ml/m<sup><b>2</b></sup>). LV stroke volume increased rapidly from pre to post-AVR (40 ± 11 to 44 ± 7 ml, p < 0.05) continuing to increase non-significantly through 4 years (49 ± 14 ml) with these LV metrics paralleling improvements in NYHA. However, LVmass/volume, a 3D measure of LV geometry, remained unchanged over 4 years.</p> <p>Conclusion</p> <p>After initial beneficial effects imparted by AVR in severe AS patients, there are, as expected, marked improvements in LV reverse remodeling. Via CMR, surgically induced benefits to LV structure and function are durable and, unexpectedly express continued, albeit markedly incomplete improvement through 4 years post-AVR concordant with sustained improved clinical status. This supports down-regulation of both mRNA and MMP activity acutely with robust suppression long term.</p

    High loading of polygenic risk for ADHD in children with comorbid aggression

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    Objective: Although attention deficit hyperactivity disorder (ADHD) is highly heritable, genome-wide association studies (GWAS) have not yet identified any common genetic variants that contribute to risk. There is evidence that aggression or conduct disorder in children with ADHD indexes higher genetic loading and clinical severity. The authors examine whether common genetic variants considered en masse as polygenic scores for ADHD are especially enriched in children with comorbid conduct disorder. Method: Polygenic scores derived from an ADHD GWAS meta-analysis were calculated in an independent ADHD sample (452 case subjects, 5,081 comparison subjects). Multivariate logistic regression analyses were employed to compare polygenic scores in the ADHD and comparison groups and test for higher scores in ADHD case subjects with comorbid conduct disorder relative to comparison subjects and relative to those without comorbid conduct disorder. Association with symptom scores was tested using linear regression. Results: Polygenic risk for ADD, derived from the meta-analysis, was higher in the independent ADHD group than in the comparison group. Polygenic score was significantly higher in ADHD case subjects with conduct disorder relative to ADHD case subjects without conduct disorder. ADHD polygenic score showed significant association with comorbid conduct disorder symptoms. This relationship was explained by,the aggression items. Conclusions: Common genetic variation is relevant to ADHD, especially in individuals with comorbid aggression. The findings suggest that the previously published ADHD GWAS meta-analysis contains weak but true associations with common variants, support for which falls below genome-wide significance levels. The findings also highlight the fact that aggression in ADHD indexes genetic as well as clinical severity

    Methods for selecting the best evidence to inform a NICE technology appraisal on selective internal radiation therapies for hepatocellular carcinoma

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    Background: Systematic reviews of medical devices are particularly challenging as the quality of evidence tends to be more limited than evidence on pharmaceutical products. This article describes the methods used to identify, select and critically appraise the best available evidence on selective internal radiation therapy devices for treating hepatocellular carcinoma, to inform a technology appraisal for the National Institute for Health and Care Excellence. Methods: A comprehensive search of ten medical databases and six grey literature sources was undertaken to identify studies of three devices (TheraSphereÂź, SIR-SpheresÂź and QuiremSpheresÂź) for treating hepatocellular carcinoma. The large evidence base was scoped before deciding what level of evidence to include for data extraction and critical appraisal. The methodological quality of the included studies was assessed using criteria relevant to each study design. Results: Electronic searches identified 4755 records; over 1000 met eligibility criteria after screening titles and abstracts. A hierarchical process was used to scope these records, prioritising comparative studies over non-comparative studies, where available. 194 full papers were ordered; 64 met the eligibility criteria. For each intervention, studies were prioritised by study design and applicability to current UK practice, resulting in 20 studies subjected to critical appraisal and data extraction. Only two trials had a low overall risk of bias. In view of the poor quality of the research evidence, our technology appraisal focused on the two higher quality trials, including a thorough critique of their reliability and generalisability to current UK practice. The 18 poorer quality studies were briefly summarised; many were very small and results were often contradictory. No definitive conclusions could be drawn from the poorer quality research evidence available. Conclusions: A systematic, pragmatic process was used to select and critically appraise the vast quantity of research evidence available in order to present the most reliable evidence on which to develop recommendations

    The positive effect of plant diversity on soil carbon depends on climate

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    Little is currently known about how climate modulates the relationship between plant diversity and soil organic carbon and the mechanisms involved. Yet, this knowledge is of crucial importance in times of climate change and biodiversity loss. Here, we show that plant diversity is positively correlated with soil carbon content and soil carbon-to-nitrogen ratio across 84 grasslands on six continents that span wide climate gradients. The relationships between plant diversity and soil carbon as well as plant diversity and soil organic matter quality (carbon-to-nitrogen ratio) are particularly strong in warm and arid climates. While plant biomass is positively correlated with soil carbon, plant biomass is not significantly correlated with plant diversity. Our results indicate that plant diversity influences soil carbon storage not via the quantity of organic matter (plant biomass) inputs to soil, but through the quality of organic matter. The study implies that ecosystem management that restores plant diversity likely enhances soil carbon sequestration, particularly in warm and arid climates.EEA Santa CruzFil: Spohn, Marie. Swedish University of Agricultural Sciences (SLU). Department of Soil and Environment; SueciaFil: Bagchi, Sumanta. Indian Institute of Science; India.Fil: Biederman, Lori A. Iowa State University. Department of Ecology, Evolution, and Organismal Biology; Estados UnidosFil: Borer, Elizabeth T. University of Minnesota. Department of Ecology, Evolution, and Behavior; Estados UnidosFil: BrĂ„then, Kari Anne. Arctic University of Norway. Department of Arctic and Marine Biology; NoruegaFil: Bugalho, Miguel N. University of Lisbon. Centre for Applied Ecology “Prof. Baeta Neves” (CEABN-InBIO). School of Agriculture; Portugal.Fil: Caldeira, Maria C. University of Lisbon. Forest Research Centre. Associate Laboratory TERRA. School of Agriculture; Portugal.Fil: Catford, Jane A. King’s College London. Department of Geography; Reino UnidoFil: Catford, Jane A. University of Melbourne. School of Agriculture, Food and Ecosystem Sciences; Australia.Fil: Collins, Scott L. University of New Mexico. Department of Biology; Estados UnidosFil: Eisenhauer, Nico. German Centre for Integrative Biodiversity Research (iDiv). Halle-Jena-Leipzig; AlemaniaFil: Eisenhauer, Nico. Leipzig University. Institute of Biology; AlemaniaFil: Peri, Pablo Luis. Instituto Nacional de TecnologĂ­a Agropecuaria (INTA). EstaciĂłn Experimental Agropecuaria Santa Cruz; Argentina.Fil: Peri, Pablo Luis. Universidad Nacional de la Patagonia Austral; Argentina.Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; Argentina.Fil: Yahdjian, Laura. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas (CONICET). Instituto de Investigaciones FisiolĂłgicas y EcolĂłgicas Vinculadas a la Agricultura (IFEVA); Argentina.Fil: Yahdjian, Laura. Universidad de Buenos Aires. Facultad de AgronomĂ­a; Argentina

    Attention deficit hyperactivity symptoms predict problematic mobile phone use

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    Attention-deficit-hyperactivity disorder (ADHD) is the most commonly diagnosed childhood disorder characterised by inattention, hyperactivity/impulsivity, or both. Some of the key traits of ADHD have previously been linked to addictive and problematic behaviours. The aim of the present study was to examine the relationship between problematic mobile phone use, smartphone addiction risk and ADHD symptoms in an adult population. A sample of 273 healthy adult volunteers completed the Adult ADHD Self-Report Scale (ASRS), the Mobile Phone Problem Usage Scale (MPPUS), and the Smartphone Addiction Scale (SAS). A significant positive correlation was found between the ASRS and both scales. More specifically, inattention symptoms and age predicted smartphone addiction risk and problematic mobile phone use. Our results suggest that there is a positive relationship between ADHD traits and problematic mobile phone use. In particular, younger adults with higher level of inattention symptoms could be at higher risk of developing smartphone addiction. The implication of our findings for theoretical frameworks of problematic mobile phone use and clinical practice are discussed
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