100 research outputs found

    Adhesion mechanics of graphene membranes

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    The interaction of graphene with neighboring materials and structures plays an important role in its behavior, both scientifically and technologically. The interactions are complicated due to the interplay between surface forces and possibly nonlinear elastic behavior. Here we review recent experimental and theoretical advances in the understanding of graphene adhesion. We organize our discussion into experimental and theoretical efforts directed toward: graphene conformation to a substrate, determination of adhesion energy, and applications where graphene adhesion plays an important role. We conclude with a brief prospectus outlining open issues.Comment: Review article to appear in special issue on graphene in Solid State Communication

    New Magnetic Anomaly Map of the Antarctic

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    The second generation Antarctic magnetic anomaly compilation for the region south of 60 degrees S includes some 3.5 million line-km of aeromagnetic and marine magnetic data that more than doubles the initial map's near-surface database. For the new compilation, the magnetic data sets were corrected for the International Geomagnetic Reference Field, diurnal effects, and high-frequency errors and leveled, gridded, and stitched together. The new magnetic data further constrain the crustal architecture and geological evolution of the Antarctic Peninsula and the West Antarctic Rift System in West Antarctica, as well as Dronning Maud Land, the Gamburtsev Subglacial Mountains, the Prince Charles Mountains, Princess Elizabeth Land, and Wilkes Land in East Antarctica and the circumjacent oceanic margins. Overall, the magnetic anomaly compilation helps unify disparate regional geologic and geophysical studies by providing new constraints on major tectonic and magmatic processes that affected the Antarctic from Precambrian to Cenozoic times.Korea Polar Research Institute (KOPRI) programs, PM15040 and PE17050Germany's AWI/Helmholtz Center for Polar and Marine ResearchFederal Institute for Geosciences and Natural ResourcesBritish Antarctic Survey/Natural Environmental Research CouncilItalian Antarctic Research ProgrammeRussian Ministry of Natural ResourcesU.S. National Science Foundation and National Space and Aeronautics AdministrationAustralian Antarctic Division and Antarctic Climate & Ecosystem Cooperative Research CentreFrench Polar InstituteGlobal geomagnetic observatories network (INTERMAGNET

    Dust in Supernovae and Supernova Remnants I : Formation Scenarios

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    Supernovae are considered as prime sources of dust in space. Observations of local supernovae over the past couple of decades have detected the presence of dust in supernova ejecta. The reddening of the high redshift quasars also indicate the presence of large masses of dust in early galaxies. Considering the top heavy IMF in the early galaxies, supernovae are assumed to be the major contributor to these large amounts of dust. However, the composition and morphology of dust grains formed in a supernova ejecta is yet to be understood with clarity. Moreover, the dust masses inferred from observations in mid-infrared and submillimeter wavelength regimes differ by two orders of magnitude or more. Therefore, the mechanism responsible for the synthesis of molecules and dust in such environments plays a crucial role in studying the evolution of cosmic dust in galaxies. This review summarises our current knowledge of dust formation in supernova ejecta and tries to quantify the role of supernovae as dust producers in a galaxy.Peer reviewe

    Discovery of widespread transcription initiation at microsatellites predictable by sequence-based deep neural network

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    Using the Cap Analysis of Gene Expression (CAGE) technology, the FANTOM5 consortium provided one of the most comprehensive maps of transcription start sites (TSSs) in several species. Strikingly, ~72% of them could not be assigned to a specific gene and initiate at unconventional regions, outside promoters or enhancers. Here, we probe these unassigned TSSs and show that, in all species studied, a significant fraction of CAGE peaks initiate at microsatellites, also called short tandem repeats (STRs). To confirm this transcription, we develop Cap Trap RNA-seq, a technology which combines cap trapping and long read MinION sequencing. We train sequence-based deep learning models able to predict CAGE signal at STRs with high accuracy. These models unveil the importance of STR surrounding sequences not only to distinguish STR classes, but also to predict the level of transcription initiation. Importantly, genetic variants linked to human diseases are preferentially found at STRs with high transcription initiation level, supporting the biological and clinical relevance of transcription initiation at STRs. Together, our results extend the repertoire of non-coding transcription associated with DNA tandem repeats and complexify STR polymorphism

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    Change in prevalence of chronic kidney disease in England over time: comparison of nationally representative cross-sectional surveys from 2003 to 2010

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    Design: Cross-sectional analysis of nationally representative Health Survey for England (HSE) random samples.Setting: England 2003 and 2009/2010.Survey participants: 13?896 adults aged 16+ participating in HSE, adjusted for sampling and non-response, 2009/2010 surveys combined.Main outcome measure: Change in prevalence of estimated glomerular filtration rate (eGFR) <60?mL/min/1.73?m2 (as proxy for stage 3–5 CKD), from 2003 to 2009/2010 based on a single serum creatinine measure using an isotope dilution mass spectrometry traceable enzymatic assay in a single laboratory; eGFR derived using Modified Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKDEPI) eGFR formulae.Analysis: Multivariate logistic regression modelling to adjust time changes for sociodemographic and clinical factors (body mass index, hypertension, diabetes, lipids). A correction factor was applied to the 2003 HSE serum creatinine to account for a storage effect.Results: National prevalence of low eGFR (<60) decreased within each age and gender group for both formulae except in men aged 65–74. Prevalence of obesity and diabetes increased in this period, while there was a decrease in hypertension. Adjustment for demographic and clinical factors led to a significant decrease in CKD between the surveyed periods. The fully adjusted OR for eGFR <60?mL/min/1.73?m2 was 0.75 (0.61 to 0.92) comparing 2009/2010 with 2003 using the MDRD equation, and was similar using the CKDEPI equation 0.73 (0.57 to 0.93).Conclusions: The prevalence of a low eGFR indicative of CKD in England appeared to decrease over this 7-year period, despite the rising prevalence of obesity and diabetes, two key causes of CKD. Hypertension prevalence declined and blood pressure control improved but this did not appear to explain the fall. Periodic assessment of eGFR and albuminuria in future HSEs is needed to evaluate trends in CKD

    Phases‚ Modes and Information Flow in Theory Development

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    Interactive Theorem Proving: An Empirical Study of User Activity

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    AbstractIn this paper the interaction between users and the interactive theorem prover HOL is investigated from a human–computer interaction perspective. First, we outline three possible views of interaction, and give a brief survey of some current interfaces and how they may be described in terms of these views. Second, we describe and present the results of an empirical study of intermediate and expert HOL users. The results are analysed for evidence in support of the proposed view of proof activity in HOL. We believe that this approach provides a principled basis for the assessment and design of interfaces to theorem provers
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