344 research outputs found

    Thermodynamic interpretation of neptunium coprecipitation in uranophane for application to the Yucca Mountain repository

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    Interpretation and modeling of recent experimental data [1] yield thermodynamic constants for the distribution of trace Np(V) between aqueous solutions and uranophane. These data indicate that neptunyl is relatively excluded from the uranyl mineral structure, but the interpretation depends on uncertain aqueous speciation and thermodynamic properties as a function of temperature. Despite Np exclusion, the low calculated solubility of uranophane at 25 °C under conditions relevant to the proposed nuclear waste repository at Yucca Mountain, Nevada, leads to Np concentrations at equilibrium with a Np-bearing uranophane solid solution that are low compared to concentrations invoked as solubility limits in Yucca Mountain performance assessments

    Global Campus: learning to walk with webbed feet

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    Universities wishing to expand their provision beyond their local catchment areas need to consider whether to bring the students to the tuition or take the tuition to the students. Current-day educational and information technologies make the latter option a much more achievable prospect than it has been in the past. Nevertheless, careful consideration needs to be given to the nature of the distance-learning students' learning experiences and the extent to which these may be comparable with those of the local students. These matters are considered in this paper against the background of the Global Campus project whereby Middlesex University's School of Computing Science sought to take its initial steps in distance-learning provision

    Observations on the distribution of serum uric acid levels in participants of the Tecumseh, Michigan, Community Health Studies : A comparison of results of one method used at two different times and of two methods used simultaneously

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    Individuals participating in the Tecumseh Community Health Study, in 1959-1960 (TCHS I) and 1962-1965 (TCHS II), had serum uric acid determinations by an enzymatic spectrophotometric method, SUA(ES), as part of a comprehensive health examination.Among the 1633 male and 1725 female subjects, the mean serum uric acid concentration had increased by 0.32 mg per 100 ml for males, and by 0.18 for females, over the the average of 4.1 yr between determinations. It was found that, approximately, 40 per cent of subjects had a decrease, and 56 per cent, an increase, in serum uric acid concentration. The change was greater than plus or minus 2.0 mg per 100 ml for 28.7 per cent of males and 19.4 per cent of females. Decreases of as much as 8.2, and increases of as much as 9.9 mg per 100 ml were observed. How much of the average increase, in an average 4.1 yr interval between tests, is due to ageing, except for males in the age range of 10-19 yr, is problematical. It seems probably that most of the average increase was due to technical factors in performance of the test.In the study of 1962-1965, serum uric acid determinations were done by two methods. An automated colorimetric method was compared with an enzymatic spectrophotometric method. Both methods showed the same types of distribution curves of serum uric acid concentrations and curves of age-sex specific mean serum uric acid.The values obtained by the automated colorimetric method were slightly, but, consistently, higher to a statistically significant degree than those of the enzymatic spectro-photometric method.For 2092 male subjects, the mean SUA(AC) was 0.21 mg per 100 ml greater than the mean SUA(ES), while for 2104 females subjects, this difference was 0.14.Of 4196 study subjects, whose sera were tested by both methods, about 90.0 per cent showed an agreement of the two values within +/- 0.9 mg per 100 ml. However, 1.9 per cent of males and 1.6 per cent of females, had ES values which exceeded AC values by 2.0 mg per 100 ml, while 2.8 per cent of male and 2.3 per cent of female subjects had AC values greater than ES values by 2.0 mg per 100 ml. The extremes of differences range from 4.4 to 7.3 mg per 100 ml.The data in this paper gives us increased confidence in the essential validity of the mean age and sex distributions of serum uric acid values, from the Tecumseh Community Health Studies, published in an earlier paper [2].It is concluded that, for the purposes of population studies, the automated colorimetric method is more advantageous than the enzymatic spectrophotometric method, because of its lesser cost.Comparison of the results of the two studies emphasizes the problems of definition of hyperuricemia. Further mathematical analysis of the distribution curves obtained in such studies may lead to definitions of normo- and hyperuricemia of greater precision for clinical purposes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32701/1/0000068.pd

    Phenomenology of the Lense-Thirring effect in the Solar System

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    Recent years have seen increasing efforts to directly measure some aspects of the general relativistic gravitomagnetic interaction in several astronomical scenarios in the solar system. After briefly overviewing the concept of gravitomagnetism from a theoretical point of view, we review the performed or proposed attempts to detect the Lense-Thirring effect affecting the orbital motions of natural and artificial bodies in the gravitational fields of the Sun, Earth, Mars and Jupiter. In particular, we will focus on the evaluation of the impact of several sources of systematic uncertainties of dynamical origin to realistically elucidate the present and future perspectives in directly measuring such an elusive relativistic effect.Comment: LaTex, 51 pages, 14 figures, 22 tables. Invited review, to appear in Astrophysics and Space Science (ApSS). Some uncited references in the text now correctly quoted. One reference added. A footnote adde

    EU-wide cross-sectional observational study of lipid-modifying therapy use in secondary and primary care: the DA VINCI study

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    Aims To provide contemporary data on the implementation of European guideline recommendations for lipid-lowering therapies (LLTs) across different settings and populations and how this impacts low-density lipoprotein cholesterol (LDL-C) goal achievement.Methods and results An 18 country, cross-sectional, observational study of patients prescribed LLT for primary or secondary prevention in primary or secondary care across Europe. Between June 2017 and November 2018, data were collected at a single visit, including LLT in the preceding 12 months and most recent LDL-C. Primary outcome was the achievement of risk-based 2016 European Society of Cardiology (ESC)/European Atherosclerosis Society (EAS) LDL-C goal while receiving stabilized LLT; 2019 goal achievement was also assessed. Overall, 5888 patients (3000 primary and 2888 secondary prevention patients) were enrolled; 54% [95% confidence interval (CI) 52-56] achieved their risk-based 2016 goal and 33% (95% CI 32-35) achieved their risk-based 2019 goal. High-intensity statin monotherapy was used in 20% and 38% of very high-risk primary and secondary prevention patients, respectively. Corresponding 2016 goal attainment was 22% and 45% (17% and 22% for 2019 goals) for very high-risk primary and secondary prevention patients, respectively. Use of moderate-high-intensity statins in combination with ezetimibe (9%), or any LLT with PCSK9 inhibitors (1%), was low; corresponding 2016 and 2019 goal attainment was 53% and 20% (ezetimibe combination), and 67% and 58% (PCSK9i combination).Conclusion Gaps between clinical guidelines and clinical practice for lipid management across Europe persist, which will be exacerbated by the 2019 guidelines. Even with optimized statins, greater utilization of non-statin LLT is likely needed to reduce these gaps for patients at highest risk.Cardiolog

    Comprehensive Rare Variant Analysis via Whole-Genome Sequencing to Determine the Molecular Pathology of Inherited Retinal Disease

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    Inherited retinal disease is a common cause of visual impairment and represents a highly heterogeneous group of conditions. Here, we present findings from a cohort of 722 individuals with inherited retinal disease, who have had whole-genome sequencing (n = 605), whole-exome sequencing (n = 72), or both (n = 45) performed, as part of the NIHR-BioResource Rare Diseases research study. We identified pathogenic variants (single-nucleotide variants, indels, or structural variants) for 404/722 (56%) individuals. Whole-genome sequencing gives unprecedented power to detect three categories of pathogenic variants in particular: structural variants, variants in GC-rich regions, which have significantly improved coverage compared to whole-exome sequencing, and variants in non-coding regulatory regions. In addition to previously reported pathogenic regulatory variants, we have identified a previously unreported pathogenic intronic variant in CHM\textit{CHM} in two males with choroideremia. We have also identified 19 genes not previously known to be associated with inherited retinal disease, which harbor biallelic predicted protein-truncating variants in unsolved cases. Whole-genome sequencing is an increasingly important comprehensive method with which to investigate the genetic causes of inherited retinal disease.This work was supported by The National Institute for Health Research England (NIHR) for the NIHR BioResource – Rare Diseases project (grant number RG65966). The Moorfields Eye Hospital cohort of patients and clinical and imaging data were ascertained and collected with the support of grants from the National Institute for Health Research Biomedical Research Centre at Moorfields Eye Hospital, National Health Service Foundation Trust, and UCL Institute of Ophthalmology, Moorfields Eye Hospital Special Trustees, Moorfields Eye Charity, the Foundation Fighting Blindness (USA), and Retinitis Pigmentosa Fighting Blindness. M.M. is a recipient of an FFB Career Development Award. E.M. is supported by UCLH/UCL NIHR Biomedical Research Centre. F.L.R. and D.G. are supported by Cambridge NIHR Biomedical Research Centre
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