In order to preserve sufficient fluorescence intensity and improve the quality of fluorescence images in optical projection tomography (OPT) imaging, a feasible acquisition solution is to... Show moreIn order to preserve sufficient fluorescence intensity and improve the quality of fluorescence images in optical projection tomography (OPT) imaging, a feasible acquisition solution is to temporally formalize the fluorescence and bright-field imaging procedure as two consecutive phases. To be specific, fluorescence images are acquired first, in a full axial-view revolution, followed by the bright-field images. Due to the mechanical drift, this approach, however, may suffer from a deviation of center of rotation (COR) for the two imaging phases, resulting in irregular 3D image fusion, with which gene or protein activity may be located inaccurately. In this paper, we address this problem and consider it into a framework based on sinogram unification so as to precisely fuse 3D images from different channels for CORs between channels that are not coincident or if COR is not in the center of sinogram. The former case corresponds to the COR deviation above; while the latter one correlates with COR alignment, without which artefacts will be introduced in the reconstructed results. After sinogram unification, inverse radon transform can be implemented on each channel to reconstruct the 3D image. The fusion results are acquired by mapping the 3D images from different channels into a common space. Experimental results indicate that the proposed framework gains excellent performance in 3D image fusion from different channels. For the COR alignment, a new automated method based on interest point detection and included in sinogram unification, is presented. It outperforms traditional COR alignment approaches in combination of effectiveness and computational complexity. Show less
Naar een betere mondelinge taalvaardigheid Het belang van feedback Spreken kun je leren- maar hoe ontwikkelen leerlingen die vaardigheid nu precies tijdens de lessen Nederlands? Deze HSN... Show moreNaar een betere mondelinge taalvaardigheid Het belang van feedback Spreken kun je leren- maar hoe ontwikkelen leerlingen die vaardigheid nu precies tijdens de lessen Nederlands? Deze HSN-bijdrage richt zich op lopend promotieonderzoek naar de relatie tussen feedback en de ontwikkeling van mondelinge taalvaardigheid in de bovenbouw van havo en vwo. In deze bijdrage wordt stilgestaan bij de meest gebruikte lesmethodes die docenten gebruiken op het gebied van spreekvaardigheid en de inzet van feedback en reflectie. Ook wordt ingegaan op hoe feedback en reflectie worden ingezet bij het leren schrijven. Wat wordt wel en niet behandeld, wat zijn volgens de methodemakers belangrijke adviezen? Zijn er parallellen te vinden in aanpak of juist verschillen? Vervolgens wordt bediscussieerd hoe deze bevindingen passen bij de lespraktijk. Show less
Zahedi, Z.; Haustein, S.; Larivière, V.; Costas Comesana, R. 2016
Massive Open Online Courses (MOOCs) are successful in delivering educational resources to the masses, however, the current retention rates—well below 10 %—indicate that they fall short in helping... Show moreMassive Open Online Courses (MOOCs) are successful in delivering educational resources to the masses, however, the current retention rates—well below 10 %—indicate that they fall short in helping their audience become effective MOOC learners. In this paper, we report two MOOC studies we conducted in order to test the effectiveness of pedagogical strategies found to be beneficial in the traditional classroom setting: retrieval practice (i.e. strengthening course knowledge through actively recalling information) and study planning (elaborating on weekly study plans). In contrast to the classroom-based results, we do not confirm our hypothesis, that small changes to the standard MOOC design can teach MOOC learners valuable self-regulated learning strategies. Show less
Huisman, B.A.; Saab, N.; Driel, J.H. van; Broek, P.W. van den 2016
Purpose: To explore and evaluate the potential value of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) for the prediction of pathologic response to neoadjuvant chemoradiotherapy ... Show morePurpose: To explore and evaluate the potential value of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) for the prediction of pathologic response to neoadjuvant chemoradiotherapy (nCRT) in oesophageal cancer.Material and methods: Twenty-six patients underwent DCE-MRI before, during (week 2-3) and after nCRT, but before surgery (pre/per/post, respectively). Histopathologic tumour regression grade (TRG) was assessed after oesophagectomy. Tumour area-under-the-concentration time curve (AUC), time-to peak (TTP) and slope were calculated. The ability of these DCE-parameters to distinguish good responders (GR, TRG 1-2) from poor responders (noGR, TRG >= 3), and pathologic complete responders (pCR) from no-pCR was assessed.Results: Twelve patients (48%) showed GR of which 8 patients (32%) pCR. Analysis of AUC change throughout treatment, AUC(per-pre), was most predictive for GR, at a threshold of 22.7% resulting in a sensitivity of 92%, specificity of 77%, PPV of 79%, and a NPV of .91%. AUC(post-pre) was most predictive for pCR, at a threshold of -24.6% resulting in a sensitivity of 83%, specificity of 88%, PPV of 71%, and a NPV of 93%. TTP and slope were not associated with pathologic response.Conclusions: This study demonstrates that changes in AUC throughout treatment are promising for prediction of histopathologic response to nCRT for oesophageal cancer. (C) 2016 Elsevier Ireland Ltd. All rights reserved. Show less
Understanding why and how students interact with educational videos is essential to further improve the quality of MOOCs. In this paper, we look at the complexity of videos to explain two related... Show moreUnderstanding why and how students interact with educational videos is essential to further improve the quality of MOOCs. In this paper, we look at the complexity of videos to explain two related aspects of student behavior: the dwelling time (how much time students spend watching a video) and the dwelling rate (how much of the video they actually see). Building on a strong tradition of psycholinguistics, we formalize a definition for information complexity in videos. Furthermore, building on recent advancements in time-on-task measures we formalize dwelling time and dwelling rate based on click-stream trace data. The resulting computational model of video complexity explains 22.44% of the variance in the dwelling rate for students that finish watching a paragraph of a video. Video complexity and student dwelling show a polynomial relationship, where both low and high complexity increases dwelling. These results indicate why students spend more time watching (and possibly contemplating about) a video. Furthermore, they show that even fairly straightforward proxies of student behavior such as dwelling can already have multiple interpretations; illustrating the challenge of sense-making from learning analytics. Show less
