Ant-attracting plant-structures: Food bodies of SE Asian Vitaceae

No abstract availabl

ZISU – Zeitschrift für interpretative Schul- und Unterrichtsforschung

Unterricht wurde lange ausschließlich als Diskurs untersucht, aber jeder Unterricht erfordert auch einen fachbezogenen und didaktischen Umgang mit materiellen Dingen. In dem neuen ZISU-Band fragen die AutorInnen aus der Perspektive erziehungswissenschaftlicher und fachdidaktischer Unterrichtsforschung, wie Dinge im Unterricht genutzt werden, wie sie zu Dingen des Unterrichts werden und sich im Unterricht verändern und welche Bedeutung Dingen bei der Konstituierung von Lernsituationen zukommt.; For a long time, teaching has been examined exclusively as discourse, but all teaching also requires a subject-related and didactic approach to material things. In the new volume of the journal "ZISU", the authors ask from the perspective of educational science and didactic teaching research how things are used in class, how they become material matters of class and how they change in class, and what significance things have for the constitution of learning situations

ZISU – Zeitschrift für interpretative Schul- und Unterrichtsforschung

Unterricht wurde lange ausschließlich als Diskurs untersucht, aber jeder Unterricht erfordert auch einen fachbezogenen und didaktischen Umgang mit materiellen Dingen. In dem neuen ZISU-Band fragen die AutorInnen aus der Perspektive erziehungswissenschaftlicher und fachdidaktischer Unterrichtsforschung, wie Dinge im Unterricht genutzt werden, wie sie zu Dingen des Unterrichts werden und sich im Unterricht verändern und welche Bedeutung Dingen bei der Konstituierung von Lernsituationen zukommt.; For a long time, teaching has been examined exclusively as discourse, but all teaching also requires a subject-related and didactic approach to material things. In the new volume of the journal "ZISU", the authors ask from the perspective of educational science and didactic teaching research how things are used in class, how they become material matters of class and how they change in class, and what significance things have for the constitution of learning situations

Numerical Simulation of Wave Fields Created by Loudspeaker Arrays

The use of loudspeaker arrays to create a spatial impression within an auditorium requires the exact knowledge of the synthesized wave field. The interaction between loudspeaker array and the enclosure can be investigated by numerical simulation. A new method for the computation of dynamical 3D sound fields is applied to obtain the impulse response from a loudspeaker array to the listening positions. 1 Introduction The creation of a three-dimensional illusion of sound sources being positioned in a virtual acoustical environment was so far restricted to binaural rendering by headphones. Advanced loudspeaker-based approaches, like the 3/2-Surround format, or Ambisonics [1] still rely on a restrained listening area, the sweet spot. A volume solution for a large listening space is offered by the Wave Field Synthesis (WFS) method, a concept developed at Delft University [2], where arrays of independently driven loudspeakers generate a prespecified soundfield. Direct sound, reflections and ..

Endoscopic assessment and grading of Barrett's esophagus using magnification endoscopy and narrow-band imaging: accuracy and interobserver agreement of different classification systems

Background: Three different classification systems for the evaluation of Barrett's esophagus (BE) using magnification endoscopy (ME) and narrow-band imaging (NBI) have been proposed. Until now, no comparative and external evaluation of these systems in a clinical-like situation has been performed. Objective: To compare and validate these 3 classification systems. Design: Prospective validation study. Setting: Tertiary-care referral center. Nine endoscopists with different levels of expertise from Europe and Japan participated as assessors. Patients: Thirty-two patients with long-segment BE. Interventions: From a group of 209 standardized prospective recordings collected on BE by using ME combined with NB!, 84 high-quality videos were randomly selected for evaluation. Histologically, 28 were classified as gastric type mucosa, 29 as specialized intestinal metaplasia (SIM), and 27 as SIM with dysplasia/cancer. Assessors were blinded to underlying histology and scored each video according to the respective classification system. Before evaluation, an educational set concerning each classification system was carefully studied. At each assessment, the same 84 videos were displayed, but in different and random order. Main Outcome Measurements: Accuracy for detection of nondysplastic and dysplastic SIM. Interobserver agreement related to each classification. Results: The median time for video evaluation was 25 seconds (interquartile range 20-39 seconds) and was longer with the Amsterdam classification (P < .001). In 65% to 69% of the videos, assessors described certainty about the histology prediction. The global accuracy was 46% and 47% using the Nottingham and Kansas classifications, respectively, and 51% with the Amsterdam classification. The accuracy for nondysplastic SIM identification ranged between 57% (Kansas and Nottingham) and 63% (Amsterdam). Accuracy for dysplastic tissue was 75%, irrespective of the classification system and assessor expertise level. Interobserver agreement ranged from fair (Nottingham, kappa = 0.34) to moderate (Amsterdam and Kansas, kappa = 0.47 and 0.44, respectively). Limitation: No per-patient analysis. Conclusions: All of the available classification systems could be used in a clinical-like environment, but with inadequate interobserver agreement. All classification systems based on combined ME and NBI, revealed substantial limitations in predicting nondysplastic and dysplastic BE when assessed externally. This technique cannot, as yet, replace random biopsies for histopathological analysis. (Gastrointest Endosc 2011;73:7-14.