1,726 research outputs found

    Methods of editing cloud and atmospheric layer affected pixels from satellite data

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    The location and migration of cloud, land and water features were examined in spectral space (reflective VIS vs. emissive IR). Daytime HCMM data showed two distinct types of cloud affected pixels in the south Texas test area. High altitude cirrus and/or cirrostratus and "subvisible cirrus" (SCi) reflected the same or only slightly more than land features. In the emissive band, the digital counts ranged from 1 to over 75 and overlapped land features. Pixels consisting of cumulus clouds, or of mixed cumulus and landscape, clustered in a different area of spectral space than the high altitude cloud pixels. Cumulus affected pixels were more reflective than land and water pixels. In August the high altitude clouds and SCi were more emissive than similar clouds were in July. Four-channel TIROS-N data were examined with the objective of developing a multispectral screening technique for removing SCi contaminated data

    Angiographic predictors of recurrence of restenosis after Wiktor stent implantation in native coronary arteries

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    Intracoronary stenting has been proposed as an adjunct to balloon angioplasty to improve the immediate and long-term results. However, late luminal narrowing has been reported following the implantation of a variety of stents. One of the studies conducted with the Wiktor stent is a prospective registry designed to evaluate the feasibility, safety and efficacy of elective stent implantation in patients with documented restenosis of a native coronary artery. To identify angiographic variables predicting recurrence of restenosis, the angiograms of the first 91 patients with successful stent implantation and without clinical evidence of (sub)acute thrombotic stent occlusion were analyzed with the Computer Assisted Angiographic Analysis System using automated edge detection. The incidence of restenosis was 44% by patient and 45% by stent according to the 0.72 mm criterion, and 30% by patient and 29% by stent according to the 50% diameter stenosis criterion. The risk for restenosis for several angiographic variables was determined using an univariate analysis and is expressed as odds ratio with corresponding confidence interval. The only statistically significant predictor of restenosis was the relative gain when it exceeded 0.48 using the 0.72 mm criterion (odds ratio 2.7, 95% confidence interval 1.1-6.4). Furthermore, the relation between the relative gain (increase in minimal luminal diameter normalized to vessel size) as angiographic index of vessel wall injury and relative loss (decrease in minimal luminal diameter normalized to vessel size) as index of neointimal thickening was analyzed using a linear regression analysis. When using the categorical approach to address restenosis, there is an increased risk for recurrent restenosis when the relative gain exceeds 0.48. The continuous approach underscores this concept by indicating a weak but positive relation between the relative gain and relative loss

    Reconstructing the reproductive mode of an Ediacaran macro-organism.

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    Enigmatic macrofossils of late Ediacaran age (580-541 million years ago) provide the oldest known record of diverse complex organisms on Earth, lying between the microbially dominated ecosystems of the Proterozoic and the Cambrian emergence of the modern biosphere. Among the oldest and most enigmatic of these macrofossils are the Rangeomorpha, a group characterized by modular, self-similar branching and a sessile benthic habit. Localized occurrences of large in situ fossilized rangeomorph populations allow fundamental aspects of their biology to be resolved using spatial point process techniques. Here we use such techniques to identify recurrent clustering patterns in the rangeomorph Fractofusus, revealing a complex life history of multigenerational, stolon-like asexual reproduction, interspersed with dispersal by waterborne propagules. Ecologically, such a habit would have allowed both for the rapid colonization of a localized area and for transport to new, previously uncolonized areas. The capacity of Fractofusus to derive adult morphology by two distinct reproductive modes documents the sophistication of its underlying developmental biology.This work has been supported by the Natural Environment Research Council [grant numbers NE/I005927/1 to C.G.K., NE/J5000045/1 to J.J.M., NE/L011409/1 to A.G.L. and NE/G523539/1 to E.G.M.], and a Henslow Junior Research Fellowship from Cambridge Philosophical Society to A.G.L.This is the author accepted manuscript. The final version is available from NPG via http://dx.doi.org/10.1038/nature1464

    Evaluating a model of best practice in primary care led post-diagnostic dementia care: Feasibility and acceptability findings from the PriDem study

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    \ua9 Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.Objectives To evaluate the feasibility and acceptability of a primary care-based intervention for improving post-diagnostic dementia care and support (PriDem), and implementation study procedures. Design A non-randomised, mixed methods, feasibility study. Setting Seven general practices from four primary care networks (PCNs) in the Northeast and Southeast of England. Participants We aimed to recruit 80 people with dementia (PWD) and 66 carers Intervention Clinical Dementia Leads delivered a 12-month intervention in participating PCNs, to develop care systems, build staff capacity and capability, and deliver tailored care and support to PWD and carers. Outcomes Recruitment and retention rates were measured. A mixed methods process evaluation evaluated feasibility and acceptability of the intervention and study procedures. Using electronic care records, researchers extracted service use data and undertook a dementia care plan audit, preintervention and postintervention, assessing feasibility of measuring the primary implementation outcome: adoption of personalised care planning by participating general practices. Participants completed quality of life, and service use measures at baseline, 4 and 9 months. Results 60 PWD (75% of recruitment target) and 51 carers (77% of recruitment target) were recruited from seven general practices across four PCNs. Retention rate at 9 months was 70.0% of PWD and 76.5% of carers. The recruitment approach showed potential for including under-represented groups within dementia. Despite implementation challenges, the intervention was feasible and acceptable, and showed early signs of sustainability. Study procedures were feasible and accessible, although researcher capacity was crucial. Participants needed time and support to engage with the study. Care plan audit procedures were feasible and acceptable. Conclusions The PriDem model is an acceptable and feasible intervention. A definitive study is warranted to fully inform dementia care policy and personalised dementia care planning guidance. Successful strategies to support inclusion of PWD and their carers in future research were developed. Trial registration number ISRCTN11677384
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