@article{HardcastleTomeCannonetal.2012, author = {Hardcastle, Nicholas and Tom{\´e}, Wolfgang A. and Cannon, Donald M. and Brouwer, Charlotte L. and Wittendorp, Paul W. H. and Dogan, Nesrin and Guckenberger, Matthias and Allaire, St{\´e}phane and Mallya, Yogish and Kumar, Prashant and Oechsner, Markus and Richter, Anne and Song, Shiyu and Myers, Michael and Polat, B{\"u}lent and Bzdusek, Karl}, title = {A multi-institution evaluation of deformable image registration algorithms for automatic organ delineation in adaptive head and neck radiotherapy}, series = {Radiation Oncology}, volume = {7}, journal = {Radiation Oncology}, number = {90}, doi = {10.1186/1748-717X-7-90}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134756}, year = {2012}, abstract = {Background: Adaptive Radiotherapy aims to identify anatomical deviations during a radiotherapy course and modify the treatment plan to maintain treatment objectives. This requires regions of interest (ROIs) to be defined using the most recent imaging data. This study investigates the clinical utility of using deformable image registration (DIR) to automatically propagate ROIs. Methods: Target (GTV) and organ-at-risk (OAR) ROIs were non-rigidly propagated from a planning CT scan to a per-treatment CT scan for 22 patients. Propagated ROIs were quantitatively compared with expert physician-drawn ROIs on the per-treatment scan using Dice scores and mean slicewise Hausdorff distances, and center of mass distances for GTVs. The propagated ROIs were qualitatively examined by experts and scored based on their clinical utility. Results: Good agreement between the DIR-propagated ROIs and expert-drawn ROIs was observed based on the metrics used. 94\% of all ROIs generated using DIR were scored as being clinically useful, requiring minimal or no edits. However, 27\% (12/44) of the GTVs required major edits. Conclusion: DIR was successfully used on 22 patients to propagate target and OAR structures for ART with good anatomical agreement for OARs. It is recommended that propagated target structures be thoroughly reviewed by the treating physician.}, language = {en} } @article{MayrKleinRutzingeretal.2021, author = {Mayr, Stefan and Klein, Igor and Rutzinger, Martin and Kuenzer, Claudia}, title = {Determining temporal uncertainty of a global inland surface water time series}, series = {Remote Sensing}, volume = {13}, journal = {Remote Sensing}, number = {17}, issn = {2072-4292}, doi = {10.3390/rs13173454}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-245234}, year = {2021}, abstract = {Earth observation time series are well suited to monitor global surface dynamics. However, data products that are aimed at assessing large-area dynamics with a high temporal resolution often face various error sources (e.g., retrieval errors, sampling errors) in their acquisition chain. Addressing uncertainties in a spatiotemporal consistent manner is challenging, as extensive high-quality validation data is typically scarce. Here we propose a new method that utilizes time series inherent information to assess the temporal interpolation uncertainty of time series datasets. For this, we utilized data from the DLR-DFD Global WaterPack (GWP), which provides daily information on global inland surface water. As the time series is primarily based on optical MODIS (Moderate Resolution Imaging Spectroradiometer) images, the requirement of data gap interpolation due to clouds constitutes the main uncertainty source of the product. With a focus on different temporal and spatial characteristics of surface water dynamics, seven auxiliary layers were derived. Each layer provides probability and reliability estimates regarding water observations at pixel-level. This enables the quantification of uncertainty corresponding to the full spatiotemporal range of the product. Furthermore, the ability of temporal layers to approximate unknown pixel states was evaluated for stratified artificial gaps, which were introduced into the original time series of four climatologic diverse test regions. Results show that uncertainty is quantified accurately (>90\%), consequently enhancing the product's quality with respect to its use for modeling and the geoscientific community.}, language = {en} } @article{SamimiFinkPaeth2012, author = {Samimi, C. and Fink, A. H. and Paeth, H.}, title = {The 2007 flood in the Sahel: causes, characteristics and its presentation in the media and FEWS NET}, series = {Natural Hazards and Earth System Sciences}, volume = {12}, journal = {Natural Hazards and Earth System Sciences}, number = {2}, doi = {10.5194/nhess-12-313-2012}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131790}, pages = {313 -- 325}, year = {2012}, abstract = {During the rainy season in 2007, reports about exceptional rains and floodings in the Sahel were published in the media, especially in August and September. Institutions and organizations like the World Food Programme (WFP) and FEWS NET put the events on the agenda and released alerts and requested help. The partly controversial picture was that most of the Sahel faced a crisis caused by widespread floodings. Our study shows that the rainy season in 2007 was exceptional with regard to rainfall amount and return periods. In many areas the event had a return period between 1 and 50 yr with high spatial heterogeneity, with the exception of the Upper Volta basin, which yielded return periods of up to 1200 yr. Despite the strong rainfall, the interpretation of satellite images show that the floods were mainly confined to lakes and river beds. However, the study also proves the difficulties in assessing the meteorological processes and the demarcation of flooded areas in satellite images without ground truthing. These facts and the somewhat vague and controversial reports in the media and FEWS NET demonstrate that it is crucial to thoroughly analyze such events at a regional and local scale involving the local population.}, language = {en} } @article{SchleicherArbetEngelsBaacketal.2019, author = {Schleicher, Bernd and Arbet-Engels, Axel and Baack, Dominik and Balbo, Matteo and Biland, Adrian and Blank, Michael and Bretz, Thomas and Bruegge, Kai and Bulinski, Michael and Buss, Jens and Doerr, Manuel and Dorner, Daniela and Elsaesser, Dominik and Grischagin, Sergej and Hildebrand, Dorothee and Linhoff, Lena and Mannheim, Karl and Mueller, Sebastian Achim and Neise, Dominik and Neronov, Andrii and Noethe, Maximilian and Paravac, Aleksander and Rhode, Wolfgang and Schulz, Florian and Sedlaczek, Kevin and Shukla, Amit and Sliusar, Vitalii and Willert, Elan and Walter, Roland}, title = {Fractional Variability—A Tool to Study Blazar Variability}, series = {Galaxies}, volume = {7}, journal = {Galaxies}, number = {2}, issn = {2075-4434}, doi = {10.3390/galaxies7020062}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-197348}, year = {2019}, abstract = {Active Galactic Nuclei emit radiation over the whole electromagnetic spectrum up to TeV energies. Blazars are one subtype with their jets pointing towards the observer. One of their typical features is extreme variability on timescales, from minutes to years. The fractional variability is an often used parameter for investigating the degree of variability of a light curve. Different detection methods and sensitivities of the instruments result in differently binned data and light curves with gaps. As they can influence the physics interpretation of the broadband variability, the effects of these differences on the fractional variability need to be studied. In this paper, we study the systematic effects of completeness in time coverage and the sampling rate. Using public data from instruments monitoring blazars in various energy ranges, we study the variability of the bright TeV blazars Mrk 421 and Mrk 501 over the electromagnetic spectrum, taking into account the systematic effects, and compare our findings with previous results. Especially in the TeV range, the fractional variability is higher than in previous studies, which can be explained by the much longer (seven years compared to few weeks) and more complete data sample.}, language = {en} } @article{ShuklaMannheim2020, author = {Shukla, A. and Mannheim, K.}, title = {Gamma-ray flares from relativistic magnetic reconnection in the jet of the quasar 3C 279}, series = {Nature Communications}, volume = {11}, journal = {Nature Communications}, doi = {10.1038/s41467-020-17912-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-231328}, year = {2020}, abstract = {Spinning black holes in the centres of galaxies can release powerful magnetised jets. When the jets are observed at angles of less than a few degrees to the line-of-sight, they are called blazars, showing variable non-thermal emission across the electromagnetic spectrum from radio waves to gamma rays. It is commonly believed that shock waves are responsible for this dissipation of jet energy. Here we show that gamma-ray observations of the blazar 3C 279 with the space-borne telescope Fermi-LAT reveal a characteristic peak-in-peak variability pattern on time scales of minutes expected if the particle acceleration is instead due to relativistic magnetic reconnection. The absence of gamma-ray pair attenuation shows that particle acceleration takes place at a distance of ten thousand gravitational radii from the black hole where the fluid dynamical kink instability drives plasma turbulence.}, language = {en} } @article{SteinbornHuestegge2017, author = {Steinborn, Michael B. and Huestegge, Lynn}, title = {Phone conversation while processing information: chronometric analysis of load effects in everyday-media multitasking}, series = {Frontiers in Psychology}, volume = {8}, journal = {Frontiers in Psychology}, number = {896}, doi = {10.3389/fpsyg.2017.00896}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158253}, year = {2017}, abstract = {This is a pilot study that examined the effect of cell-phone conversation on cognition using a continuous multitasking paradigm. Current theorizing argues that phone conversation affects behavior (e.g., driving) by interfering at a level of cognitive processes (not peripheral activity) and by implying an attentional-failure account. Within the framework of an intermittent spare-utilized capacity threading model, we examined the effect of aspects of (secondary-task) phone conversation on (primary-task) continuous arithmetic performance, asking whether phone use makes components of automatic and controlled information-processing (i.e., easy vs. hard mental arithmetic) run more slowly, or alternatively, makes processing run less reliably albeit with the same processing speed. The results can be summarized as follows: While neither expecting a text message nor expecting an impending phone call had any detrimental effects on performance, active phone conversation was clearly detrimental to primary-task performance. Crucially, the decrement imposed by secondary-task (conversation) was not due to a constant slowdown but is better be characterized by an occasional breakdown of information processing, which differentially affected automatic and controlled components of primary-task processing. In conclusion, these findings support the notion that phone conversation makes individuals not constantly slower but more vulnerable to commit attention failure, and in this way, hampers stability of (primary-task) information processing.}, language = {en} }