178 research outputs found
SVNR: Spatially-variant Noise Removal with Denoising Diffusion
Denoising diffusion models have recently shown impressive results in
generative tasks. By learning powerful priors from huge collections of training
images, such models are able to gradually modify complete noise to a clean
natural image via a sequence of small denoising steps, seemingly making them
well-suited for single image denoising. However, effectively applying denoising
diffusion models to removal of realistic noise is more challenging than it may
seem, since their formulation is based on additive white Gaussian noise, unlike
noise in real-world images. In this work, we present SVNR, a novel formulation
of denoising diffusion that assumes a more realistic, spatially-variant noise
model. SVNR enables using the noisy input image as the starting point for the
denoising diffusion process, in addition to conditioning the process on it. To
this end, we adapt the diffusion process to allow each pixel to have its own
time embedding, and propose training and inference schemes that support
spatially-varying time maps. Our formulation also accounts for the correlation
that exists between the condition image and the samples along the modified
diffusion process. In our experiments we demonstrate the advantages of our
approach over a strong diffusion model baseline, as well as over a
state-of-the-art single image denoising method
E-cigarettes and the Multiple Responsibilities of the FDA
This paper considers the responsibilities of the FDA with regard to disseminating information about the benefits and harms of e-cigarettes. Tobacco harm reduction advocates claim that the FDA has been overcautious and has violated ethical obligations by failing to clearly communicate to the public that e-cigarettes are far less harmful than cigarettes. We argue, by contrast, that the FDA’s obligations in this arena are more complex than they may appear at first blush. Though the FDA is accountable for informing the public about the health risks and benefits of products it regulates, it also has other roles (and attendant responsibilities) that inform when and how it should disseminate information. In addition to being a knowledge purveyor, it is also a knowledge producer, an advisor to the public, and a practical agent shaping the material conditions in which people make health-related choices. In our view, those other roles call for caution in the way the FDA interprets and communicates the available evidence
Antiresonance and Localization in Quantum Dynamics
The phenomenon of quantum antiresonance (QAR), i.e., exactly periodic
recurrences in quantum dynamics, is studied in a large class of nonintegrable
systems, the modulated kicked rotors (MKRs). It is shown that asymptotic
exponential localization generally occurs for (a scaled ) in the
infinitesimal vicinity of QAR points . The localization length
is determined from the analytical properties of the kicking potential. This
``QAR-localization" is associated in some cases with an integrable limit of the
corresponding classical systems. The MKR dynamical problem is mapped into
pseudorandom tight-binding models, exhibiting dynamical localization (DL). By
considering exactly-solvable cases, numerical evidence is given that
QAR-localization is an excellent approximation to DL sufficiently close to QAR.
The transition from QAR-localization to DL in a semiclassical regime, as
is varied, is studied. It is shown that this transition takes place via a
gradual reduction of the influence of the analyticity of the potential on the
analyticity of the eigenstates, as the level of chaos is increased.Comment: To appear in Physical Review E. 51 pre-print pages + 9 postscript
figure
Nonlinearity effects in the kicked oscillator
The quantum kicked oscillator is known to display a remarkable richness of
dynamical behaviour, from ballistic spreading to dynamical localization. Here
we investigate the effects of a Gross Pitaevskii nonlinearity on quantum
motion, and provide evidence that the qualitative features depend strongly on
the parameters of the system.Comment: 4 pages, 5 figure
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5-SPICE: the application of an original framework for community health worker program design, quality improvement and research agenda setting
Introduction: Despite decades of experience with community health workers (CHWs) in a wide variety of global health projects, there is no established conceptual framework that structures how implementers and researchers can understand, study and improve their respective programs based on lessons learned by other CHW programs. Objective: To apply an original, non-linear framework and case study method, 5-SPICE, to multiple sister projects of a large, international non-governmental organization (NGO), and other CHW projects. Design: Engaging a large group of implementers, researchers and the best available literature, the 5-SPICE framework was refined and then applied to a selection of CHW programs. Insights gleaned from the case study method were summarized in a tabular format named the ‘5×5-SPICE chart’. This format graphically lists the ways in which essential CHW program elements interact, both positively and negatively, in the implementation field. Results: The 5×5-SPICE charts reveal a variety of insights that come from a more complex understanding of how essential CHW projects interact and influence each other in their unique context. Some have been well described in the literature previously, while others are exclusive to this article. An analysis of how best to compensate CHWs is also offered as an example of the type of insights that this method may yield. Conclusions: The 5-SPICE framework is a novel instrument that can be used to guide discussions about CHW projects. Insights from this process can help guide quality improvement efforts, or be used as hypothesis that will form the basis of a program's research agenda. Recent experience with research protocols embedded into successfully implemented projects demonstrates how such hypothesis can be rigorously tested
Coronary Atherosclerotic Plaque Activity and Future Coronary Events
This study was funded by a Wellcome Trust Senior Investigator Award (WT103782AIA). Image analysis was supported by National Institutes for Health (R34HL161195 and 1R01HL135557). The content is solely the responsibility of the authors and does not necessarily represent the official views of the Wellcome Trust or the National Institutes of Health. The British Heart Foundation supports DEN (CH/09/002, RG/16/10/32375, RE/18/5/34216), MRD (FS/SCRF/21/32010), NLM (CH/F/21/90010, RG/20/10/34966, RE/18/5/34216) AJM (AA/18/3/34220) and MCW (FS/ICRF/20/26002) and DD (FS/RTF/20/30009, NH/19/1/34595, PG/18/35/33786, PG/15/88/31780, PG/17/64/33205). MRD is the recipient of the Sir Jules Thorn Award for Biomedical Research 2015 (15/JTA). PJS is supported by outstanding investigator award National Institutes for Health (R35HL161195). JK is supported by the National Science Centre 2021/41/B/NZ5/02630. EvB is supported by SINAPSE (www.sinapse.ac.uk). AB is supported by a Clinical Research Training Fellowships (MR/V007254/1). DD is supported by Chest Heart and Stroke Scotland (19/53), Tenovus Scotland (G.18.01), and Friends of Anchor and Grampian NHS-Endowments. The Edinburgh Clinical Research Facilities, Edinburgh Imaging facility and Edinburgh Clinical Trials Unit are supported by the National Health Service Research Scotland through National Health Service Lothian Health Board. The Leeds Clinical Research Facilities are supported by the UK National Institute for Health Research (NIHR) via its Clinical Research Facility programme. The work at Cedars-Sinai Medical Center (the Los Angeles site) was supported in part by the Dr. Miriam and Sheldon G. Adelson Medical Research Foundation. For the purpose of open access, the author has applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising from this submission. The Chief Investigator and Edinburgh Clinical Trials Unit had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.Peer reviewedPostprin
Exposure to phthalates among premenstrual girls from rural and urban Gharbiah, Egypt: A pilot exposure assessment study
<p>Abstract</p> <p>Background</p> <p>Phthalates have been identified as endocrine active compounds associated with developmental and reproductive toxicity. The exposure to phthalates in premenstrual Egyptian females remains unknown. The objective of this study was to characterize phthalate exposure of a potentially vulnerable population of premenstrual girls from urban and rural Egypt.</p> <p>Materials and methods</p> <p>We collected one spot urine sample from 60 10-13 year old females, 30 from rural Egypt, and 30 from urban Egypt from July to October 2009. Samples were analyzed for 11 phthalate metabolites. Additionally, we collected anthropometrics as well as questionnaire data concerning food storage behaviors, cooking practices, and cosmetic use. Phthalate metabolite concentrations were compared between urban and rural Egyptians as well as to age and gender matched Americans.</p> <p>Results</p> <p>Monoethyl phthalate (MEP), was detected at the highest concentration in urine of Egyptian girls (median: 43.2 ng/mL in rural, 98.8 ng/mL in urban). Concentrations of urinary metabolites of di-(2-ethylhexyl) phthalate and dibutyl phthalate were comparable between Egyptians and age matched US girls. Storage of food in plastic containers was a statistically significant predictor of urinary mono-isobutyl phthalate (MiBP) concentrations when comparing covariate adjusted means.</p> <p>Conclusions</p> <p>Urinary concentrations of phthalate metabolites were similar in Egyptian and US populations, suggesting that phthalate exposure also occurs in developing nations. Dietary intake is likely an important route of exposure to phthalates in both urban and rural populations.</p
PDBe: improved findability of macromolecularstructure data in the PDB
© 2019 The Authors. Published by OUP. This is an open access article available under a Creative Commons licence.
The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1093/nar/gkz990The Protein Data Bank in Europe (PDBe), a founding member of the Worldwide Protein Data Bank (wwPDB), actively participates in the deposition, curation, validation, archiving and dissemination of macromolecular structure data. PDBe supports diverse research communities in their use of macromolecular structures by enriching the PDB data and by providing advanced tools and services for effective data access, visualization and analysis. This paper details the enrichment of data at PDBe, including mapping of RNA structures to Rfam, and identification of molecules that act as cofactors. PDBe has developed an advanced search facility with ∼100 data categories and sequence searches. New features have been included in the LiteMol viewer at PDBe, with updated visualization of carbohydrates and nucleic acids. Small molecules are now mapped more extensively to external databases and their visual representation has been enhanced. These advances help users to more easily find and interpret macromolecular structure data in order to solve scientific problems.The Protein Data Bank in Europe is supported by European Molecular Biology Laboratory-European Bioinformatics Institute; Wellcome Trust [104948]; Biotechnology and Biological Sciences Research Council [BB/N019172/1, BB/G022577/1, BB/J007471/1, BB/K016970/1, BB/K020013/1, BB/M013146/1, BB/M011674/1, BB/M020347/1, BB/M020428/1, BB/P024351/1]; European Union [284209]; ELIXIR and Open Targets. Funding for open access charge: EMB
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