390 research outputs found
Evaluation of inferential methods for the net benefit and win ratio statistics
No full textGeneral Pairwise Comparison (GPC) statistics, such as the net benefit and the win ratio, have been applied in clinical trial data analysis and design. In the literature, inferential methods based on re-sampling, asymptotic or exact methods have been proposed for these GPC statistics, but they have not been compared to each other. In this paper, the small sample bias of the variance estimation, Type I error control and 95% confidence interval coverage of the GPC inferential methods are evaluated using simulations. The exact permutation and bootstrap tests perform best in all evaluated aspects for the net benefit, while the exact bootstrap test performs best for the win ratio.This work was supported by the European Cardiovascular Research Institute (ECRI).Verbeeck, J (reprint author), Agoralaan Bldg D, B-3590 Diepenbeek, Belgium.
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Georg Bernard Verbeeck and his Vanitas from the Sternberg collection at the château in Častolovice
No full textThe article deals with the cabinet picture Vanitas from the Sternberg collection, exhibited at the château in Častolovice in eastern Bohemia. This still life on copper plate was painted by Georg Bernard Verbeeck (†1673), a portraitist from the German town of Emmerich near the Dutch border. He moved to Prague with his nephew Jodokus Justus (1646–1700) and worked for the Lobkowitz family in Roudnice nad Labem and the Kolowrat family in Rychnov nad Kněžnou. The only painting attributed to Verbeeck that is not a portrait is an exploratory still life that has survived in relatively good condition. The work is signed and partially dated. The painting was in the possession of the Sternbergs at least from the time of Adolf Wratislaw of Sternberg (1627?–1703) and in the family asset inventories in Zásmuky and Častolovice it was designated Ein Todtenkopf The painting demonstrates exceptional realism and attention to detail. It combines many artistic symbols typical of the 17th century, expressing the themes of the finiteness of life and profligacy. This study, which is an addendum to our knowledge of the work of the almost unknown author of this painting, may help art historians in the future in the attribution of other paintings by Verbeeck, or more exactly, his circle
The impact of Paul Philippot on the theory and history of conservation/restoration
No full textpeer reviewedPaul Philippot (1925–2016) was an influential conservation theoretician and author in addi- tion to serving as an important leader or col- laborator with major conservation institutions in Europe (ICR, ICCROM, IIC, UNESCO, ICOM, etc.). He was an art historian born into a Belgian fam- ily of conservator-restorers. The authors were privileged to interview him in 1997, 2009 and 2015. Verbeeck discusses Philippot’s relation to and reinterpretation of the philosophy of Cesare Brandi, his definition of restoration as both an intellectual judgment and a critical act, and his influence on the establishment of an interdis- ciplinary curriculum for pioneer training pro- grams. Stoner describes Philippot’s emphasis on the impact of language on communication of philosophical concepts in his 1997 interview in addition to key points in his publications once they were available in English, especially his de- scription of patina as the normal effect that time has on material and the search for equilibrium in cleaning paintings
Chirality in EELS: Progress and Applications
No full textEnnen I, Stöger-Pollach M, Schattschneider P, Verbeeck J, Nellist P. Chirality in EELS: Progress and Applications. In: Grogger W, Hofer F, Pölt P, eds. MC2009 Proceedings. Vol 3. Facultas Verlag; 2009: 119-120
Influence of weather parameters on a fireball’s dark flight
No full textThe computation of the dark flight of a bright fireball requires knowledge of the atmospheric parameters. In particular wind and wind direction as a function of height are crucial for an accurate trajectory. In this paper we compare different sources of sounding balloon and model data, and study the effect on the dark flight.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Planetary Exploratio
A Representative Survey of M.S. Patients on Attitudes toward the Benefits and Risks of Drug Therapy
No full textBackground: Although M.S. patients face significant trade-offs between risks and benefits of drug therapy, little is known of their attitudes toward these risks and benefits. Methods: A representative telephone survey of 200 patients with relapsing remitting M.S. Results: Respondents suffered substantial disability, most of them requiring a wheel chair or support for walking any significant distance, and over half suffering relapses in the past year. All were on drug therapy; half had switched drugs; 1/3 had switched at least twice.Most patients had seen their neurologist at least 4 times in the previous two years and said they and their physician were equally involved in drug decisions. About 55% said they would definitely or probably use a drug that significantly reduces frequency of relapse or progression in disability even if the drug involves a 1-in-1,000 chance of a fatal side-effect.Willingness to tolerate risk bore little relationship with disability levels. A substantial majority agreed that the FDA should tightly control drugs with safety concerns, but a larger majority agreed that once the FDA has provided a warning, patients should be free to decide with their physician whether to use such drugs. Virtually all said they were willing to visit their neurologist more often in order to use risky drugs. Conclusions: M.S. patients are accustomed to playing a large role in their own drug therapy but do so in close collaboration with their physicians.After the FDA has reviewed drug safety and provided reasonable warnings, many M.S. patients wish to be free to choose to incur a 1-in-1,000 (or even greater) risk of a fatal side-effect in return for significantly more effective drugs, and are willing to work with the physicians in doing so.
Conceptual approach to community-involved, drone-assisted meteorite searching: strategy to find fusion-crusted meteorites
No full textMeteorites offer valuable insights into the composition of asteroids and geological processes contributing to planet formation inside the solar system. Their rapid retrieval after fireball sightings allows this science potential to be used. Finding new meteorites is notoriously difficult due to various complicating factors. A promising search strategy can involve the aerial vantage point of drones (aka: UAV, RPAS). However, drone regulations by the European Union Aviation Safety Agency (EASA) and complex zonation of airspace will impact flight operations, which makes drone-assisted searching in Europe more complex than in e.g. desert environments. Here we present the results of an interdisciplinary desk study, which aimed at proposing a conceptual framework for drone-assisted meteorite searching. We propose the development of an open-source detection and coordination tool to improve aerial assistance by drones during field searches. The design provides drone enthusiasts (referred to as ‘community drones’) and researchers with a platform to coordinate joint drone-based search operations. Image processing is envisioned to take place via a convolutional neural network pipeline, after which high-likelihood locations are identified and manually verified to recover a potential meteorite. This approach will require the development of multiple models to account for variations in soils and vegetation. The tool supports multi-drone coordination, providing path planning functionality and support for a broad range of (commercially) available drone models (e.g. DJI) and sensor types (e.g. RGB, thermal). Considering EASA drone regulations, the use of the DJI Mini 3 Pro is favoured as an accessible community drone. Follow-up research, implementing the proposed conceptual approach, should validate the design presented here and highlight practical areas of improvement.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Planetary Exploratio
Morphometrics of regmaglypts based on a 3D Model of the fusion-crusted ordinary chondrite Broek in Waterland (L6)
No full textRegmaglypts are shallow depressions on meteorite surfaces formed by ablation processes during atmospheric entry. These features can potentially offer insights in breakup events. However, quantitative methods to analyse regmaglypts have not yet been proposed to date. Here we present the results of a study to evaluate breakup processes during the luminous flight by analysing regmaglypt morphometrics. We developed a novel approach based on a 3D shape model of the Broek in Waterland meteorite that was generated using photogrammetry. We converted sections of the 3D model into a smoothed Digital Elevation Model (DEM) that contained the fracture surfaces adorned with regmaglypts. Lending techniques from terrain analyses, we extracted Land Surface Parameters (LSP) and delineated regmaglypts based on the mean curvature inflection point. The outliers of the regmaglypt population were discarded based on mean and total curvature scatter plots. The mean, profile, tangential, total and Gaussian curvatures were found to be most descriptive of regmaglypt morphologies. Various other curvature types were tested and found to be consistent across the studied regmaglypt population. Using this initial framework, we found that the two regmaglypted surfaces of the Broek in Waterland meteorite appear to be similar. This would reflect similar formative conditions, which we interpret to be most consistent with formation from the same breakup event. Future studies will aim to expand the presented method to regmaglypt populations of other L6 meteorites to understand how surface characteristics can inform us on ablation and breakup processes.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Planetary Exploratio
Core-loss EELS dataset and neural networks for element identification
No full textAbstract: We present a large dataset containing simulated core-loss electron energy loss spectroscopy (EELS) spectra with the elemental content as ground-truth labels. Additionally we present some neural networks trained on this data for element identification.\ua0 The simulated dataset contains zero padded core-loss spectra from 0 to 3072 eV, which represents 107 core-loss edges through all 80 elements from Be up to Bi. The core-loss edges are calculated from the generalised oscillator strength (GOS) database presented by Zhang\ua0et al.[1] Generic fine structures using lifetime broadened peaks are used to imitate fine structure due to solid-state effects in experimental spectra. Generic low-loss regions are used to imitate the effect of multiple scattering. Each spectrum contains at least one edge of a given query element and possibly additional edges depending on samples drawn from The Materials Project [2]. The dataset contains for each of the 80 elements: 7000 training spectra, 1500 test spectra, 600 validation spectra and 100 spectra representing only the query element. This results in a total 736 000 labeled spectra. Code on how to\ua0 - read the simulated data - transform HDF5 format to TFRecord format - train and evaluate neural networks using the simulated data - use the trained networks for automated element identification is available on GitHub at arnoannys/EELS_ID A full report on the simulation of the dataset and the training and evaluation of the neural networks can be found at: \ua0 \ua0 \ua0 \ua0 \ua0 \ua0 \ua0 \ua0 \ua0 \ua0Annys, A., Jannis, D. & Verbeeck, J. Deep learning for automated materials characterisation in core-loss electron energy loss spectroscopy.\ua0Sci Rep\ua013, 13724 (2023). https://doi.org/10.1038/s41598-023-40943-7 [1] Zezhong Zhang, Ivan Lobato, Daen Jannis, Johan Verbeeck, Sandra Van Aert, & Peter Nellist. (2023). Generalised oscillator strength for core-shell electron excitation by fast electrons based on Dirac solutions (1.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.7729585 [2] Anubhav Jain, Shyue Ping Ong, Geoffroy Hautier, Wei Chen, William Davidson Richards, Stephen Dacek, Shreyas Cholia, Dan Gunter, David Skinner, Gerbrand Ceder, Kristin A. Persson; Commentary: The Materials Project: A materials genome approach to accelerating materials innovation. __APL Mater__ 1 July 2013; 1 (1): 011002. [https://doi.org/10.1063/1.4812323](https://doi.org/10.1063/1.4812323
Urban Meteor Map: a map-based forecast of hourly rates for visual observers
No full textThe visible rate of meteors is dependent on various local viewing condition during shower peak nights. The interrelationship of the visible fraction of the night sky, radiant elevation and effects of the light pollution on sky brightness confounds outreach efforts to manage realistic expectations for visual meteor observations by the public. The Urban Meteor Map offers a map-based forecast of hourly rates to help make the effects of local viewing conditions more insightful. The project generates maps based on raster data for parameters in the Zenithal Hourly Rate formula. A Digital Surface Model (DSM) covering the Netherlands was used to generate maps of the visible percentage of the sky. At 5 m resolution this DSM offers insights into obstruction by buildings, vegetation and topography. To incorporate effects of light pollution, a national sky brightness map for cloudless nights was converted into Naked Eye Limiting Magnitudes (NELM). Combined with known shower parameters such as population index and radiant height, maps were generated with hourly rates forecasts at local and national scales. Ultimately, observing conditions will remain dependent on the individual observers, their night adaptation and local light interference. The Urban Meteor Map aims to helps raise awareness for the effects of light pollution, and thus promotes exploration of local living environment to seek the best viewing spots for meteor showers.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Planetary Exploratio
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