7,001 research outputs found

    Time to publication for NIHR HTA programme-funded research: a cohort study

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    ObjectiveTo assess the time to publication of primary research and evidence syntheses funded by the National Institute for Health Research (NIHR) Health Technology Assessment (HTA) Programme published as a monograph in Health Technology Assessment and as a journal article in the wider biomedical literature.Study designRetrospective cohort study.SettingPrimary research and evidence synthesis projects funded by the HTA Programme were included in the cohort if they were registered in the NIHR research programmes database and was planned to submit the draft final report for publication in Health Technology Assessment on or before 9 December 2011.Main outcome measuresThe median time to publication and publication at 30?months in Health Technology Assessment and in an external journal were determined by searching the NIHR research programmes database and HTA Programme website.ResultsOf 458 included projects, 184 (40.2%) were primary research projects and 274 (59.8%) were evidence syntheses. A total of 155 primary research projects had a completion date; the median time to publication was 23?months (26.5 and 35.5?months to publish a monograph and to publish in an external journal, respectively) and 69% were published within 30?months. The median time to publication of HTA-funded trials (n=126) was 24?months and 67.5% were published within 30?months. Among the evidence syntheses with a protocol online date (n=223), the median time to publication was 25.5?months (28?months to publication as a monograph), but only 44.4% of evidence synthesis projects were published in an external journal. 65% of evidence synthesis studies had been published within 30.0?months.ConclusionsResearch funded by the HTA Programme publishes promptly. The importance of Health Technology Assessment was highlighted as the median time to publication was 9?months shorter for a monograph than an external journal article

    Monte Carlo cluster algorithm for fluid phase transitions in highly size-asymmetrical binary mixtures

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    Highly size-asymmetrical fluid mixtures arise in a variety of physical contexts, notably in suspensions of colloidal particles to which much smaller particles have been added in the form of polymers or nanoparticles. Conventional schemes for simulating models of such systems are hamstrung by the difficulty of relaxing the large species in the presence of the small one. Here we describe how the rejection-free geometrical cluster algorithm (GCA) of Liu and Luijten [Phys. Rev. Lett 92, 035504 (2004)] can be embedded within a restricted Gibbs ensemble to facilitate efficient and accurate studies of fluid phase behavior of highly size-asymmetrical mixtures. After providing a detailed description of the algorithm, we summarize the bespoke analysis techniques of Ashton et al. [J. Chem. Phys. 132, 074111 (2010)] that permit accurate estimates of coexisting densities and critical-point parameters. We apply our methods to study the liquid--vapor phase diagram of a particular mixture of Lennard-Jones particles having a 10:1 size ratio. As the reservoir volume fraction of small particles is increased in the range 0--5%, the critical temperature decreases by approximately 50%, while the critical density drops by some 30%. These trends imply that in our system, adding small particles decreases the net attraction between large particles, a situation that contrasts with hard-sphere mixtures where an attractive depletion force occurs.Comment: 11 pages, 10 figure

    Vortex Velocity in Turbulent He II Counterflow

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    We have used the ion-vortex interaction to measure the drift velocity of the vorticity present in turbulent counterflow, and find that it moves in the direction of normal-fluid flow. The result is in direct conflict with a central assumption of the presently accepted model of the turbulent state

    Multistability of free spontaneously-curved anisotropic strips

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    Multistable structures are objects with more than one stable conformation, exemplified by the simple switch. Continuum versions are often elastic composite plates or shells, such as the common measuring tape or the slap bracelet, both of which exhibit two stable configurations: rolled and unrolled. Here we consider the energy landscape of a general class of multistable anisotropic strips with spontaneous Gaussian curvature. We show that while strips with non-zero Gaussian curvature can be bistable, strips with positive spontaneous curvature are always bistable, independent of the elastic moduli, strips of spontaneous negative curvature are bistable only in the presence of spontaneous twist and when certain conditions on the relative stiffness of the strip in tension and shear are satisfied. Furthermore, anisotropic strips can become tristable when their bending rigidity is small. Our study complements and extends the theory of multistability in anisotropic shells and suggests new design criteria for these structures.Comment: 20 pages, 10 figure

    Diffractive Contribution to the Elasticity and the Nucleonic Flux in the Atmosphere

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    We calculate the average elasticity considering non-diffractive and single diffractive interactions and perform an analysis of the cosmic-ray flux by means of an analytical solution for the nucleonic diffusion equation. We show that the diffractive contribution is important for the adequate description of the nucleonic and hadronic fluxes in the atmosphere.Comment: 10 pages, latex, 2 figures (uuencoded PostScript

    Identification of diverse database subsets using property-based and fragment-based molecular descriptions

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    This paper reports a comparison of calculated molecular properties and of 2D fragment bit-strings when used for the selection of structurally diverse subsets of a file of 44295 compounds. MaxMin dissimilarity-based selection and k-means cluster-based selection are used to select subsets containing between 1% and 20% of the file. Investigation of the numbers of bioactive molecules in the selected subsets suggest: that the MaxMin subsets are noticeably superior to the k-means subsets; that the property-based descriptors are marginally superior to the fragment-based descriptors; and that both approaches are noticeably superior to random selection

    Fast Simulation of Facilitated Spin Models

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    We show how to apply the absorbing Markov chain Monte Carlo algorithm of Novotny to simulate kinetically constrained models of glasses. We consider in detail one-spin facilitated models, such as the East model and its generalizations to arbitrary dimensions. We investigate how to maximise the efficiency of the algorithms, and show that simulation times can be improved on standard continuous time Monte Carlo by several orders of magnitude. We illustrate the method with equilibrium and aging results. These include a study of relaxation times in the East model for dimensions d=1 to d=13, which provides further evidence that the hierarchical relaxation in this model is present in all dimensions. We discuss how the method can be applied to other kinetically constrained models.Comment: 8 pages, 4 figure

    Reduced air–sea CO2 exchange in the Atlantic Ocean due to biological surfactants

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    This is the author accepted manuscript. The final version is available from Springer Nature via the DOI in this recordOcean CO2 uptake accounts for 20–40% of the post-industrial sink for anthropogenic CO2. The uptake rate is the product of the CO2 interfacial concentration gradient and its transfer velocity, which is controlled by spatial and temporal variability in near-surface turbulence. This variability complicates CO2 flux estimates and in large part reflects variable sea surface microlayer enrichments in biologically derived surfactants that cause turbulence suppression. Here we present a direct estimate of this surfactant effect on CO2 exchange at the ocean basin scale, with derived relationships between its transfer velocity determined experimentally and total surfactant activity for Atlantic Ocean surface seawaters. We found up to 32% reduction in CO2 exchange relative to surfactant-free water. Applying a relationship between sea surface temperature and total surfactant activity to our results gives monthly estimates of spatially resolved ‘surfactant suppression’ of CO2 exchange. Large areas of reduced CO2 uptake resulted, notably around 20° N, and the magnitude of the Atlantic Ocean CO2 sink for 2014 was decreased by 9%. This direct quantification of the surfactant effect on CO2 uptake at the ocean basin scale offers a framework for further refining estimates of air–sea gas exchange up to the global scale.This work was supported by grants from the Leverhulme Trust to R.C.U.G. (RPG-303) and the UK Natural Environment Research Council (NERC) to R.C.U.G. (NE/K00252X/1) and J.D.S. (NE/K002511/1). Both NERC grants are components of RAGNARoCC (Radiatively Active Gases from the North Atlantic Region and Climate Change), which contributes to NERC's Greenhouse Gas Emissions and Feedbacks programme (www.nerc.ac.uk/research/funded/programmes/greenhouse). J.D.S. and I.A. acknowledge additional support from the European Space Agency (grant 4000112091/14/I-LG). R.P. acknowledges support from T. Wagner. This study is a contribution to the international IMBeR project and was supported by UK NERC National Capability funding to Plymouth Marine Laboratory and the National Oceanography Centre, Southampton. This is contribution no. 324 of the AMT programme

    Antibody responses to nasopharyngeal carriage of Streptococcus pneumoniae in adults: A longitudinal household study

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    Background. Natural immunity to Streptococcus pneumoniae is thought to be induced by exposure to S. pneumoniae or cross-reactive antigens. No longitudinal studies of carriage of and immune responses to S. pneumoniae have been conducted using sophisticated immunological laboratory techniques.Methods. We enrolled 121 families with young children into this study. Nasopharyngeal (NP) swabs were collected monthly for 10 months from all family members and were cultured in a standard fashion. Cultured S. pneumoniae isolates were serotyped. At the beginning (month 0) and end (month 10) of the study, venous blood was collected from family members 118 years old. Serotype-specific antipolysaccharide immunoglobulin G (IgG) and functional antibody and antibodies to pneumolysin, pneumococcal surface protein A (PspA), and pneumococcal surface antigen A (PsaA) were measured in paired serum samples.Results. Levels of anticapsular IgG increased significantly after carriage of serotypes 9V, 14, 18C, 19F, and 23F by an individual or family member. For serotype 14, a higher level of anticapsular IgG at the beginning of the study was associated with reduced odds of carriage (P = .0006). There was a small (similar to 20%) but significant increase in titers of antibodies to PsaA and pneumolysin but no change in titers of antibody to PspA.Conclusions. Adults respond to NP carriage by mounting anticapsular and weak antiprotein antibody responses, and naturally induced anticapsular IgG can prevent carriage
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