Semi-Automatic Cell Correspondence Analysis Using Iterative Point Cloud Registration

In the field of biophysics, deformation of in-vitro model tissues is an experimental technique to explore the response of tissue to a mechanical stimulus. However, automated registration before and after deformation is an ongoing obstacle for measuring the tissue response on the cellular level. Here, we propose to use an iterative point cloud registration (IPCR) method, for this problem. We apply the registration method on point clouds representing the cellular centers of mass, which are evaluated with aWatershed based segmentation of phase-contrast images of living tissue, acquired before and after deformation. Preliminary evaluation of this method on three data sets shows high accuracy, with 82% - 92% correctly registered cells, which outperforms coherent point drift (CPD). Hence, we propose the application of the IPCR method on the problem of cell correspondence analysis

Heat transfer in separated flows on the pressure side of turbine blades

Heat transfer in separated flows on the pressure side of a typical high lift turbine profile is numerically investigated by means of an in-house CFD code. The numerical code was first validated on attached flows in turbine blades. To obtain flow separation cases, the profile is subject to large negative incidences so that a separation bubble is obtained at the pressure side. The numerical results are compared to available experimental data for code validation. It is shown how local minima and maxima values of the heat transfer coefficient are related to the separation and reattachment points, where the velocity component perpendicular to the wall is shown to have a significant effect on the heat transfe

Visuo-perceptual capabilities predict sensitivity for coinciding auditory and visual transients in multi-element displays.

In order to obtain a coherent representation of the outside world, auditory and visual information are integrated during human information processing. There is remarkable variance among observers in the capability to integrate auditory and visual information. Here, we propose that visuo-perceptual capabilities predict detection performance for audiovisually coinciding transients in multi-element displays due to severe capacity limitations in audiovisual integration. In the reported experiment, we employed an individual differences approach in order to investigate this hypothesis. Therefore, we measured performance in a useful-field-of-view task that captures detection performance for briefly presented stimuli across a large perceptual field. Furthermore, we measured sensitivity for visual direction changes that coincide with tones within the same participants. Our results show that individual differences in visuo-perceptual capabilities predicted sensitivity for the presence of audiovisually synchronous events among competing visual stimuli. To ensure that this correlation does not stem from superordinate factors, we also tested performance in an unrelated working memory task. Performance in this task was independent of sensitivity for the presence of audiovisually synchronous events. Our findings strengthen the proposed link between visuo-perceptual capabilities and audiovisual integration. The results also suggest that basic visuo-perceptual capabilities provide the basis for the subsequent integration of auditory and visual information

The Beep-Speed Illusion: Non-Spatial Tones Increase Perceived Speed of Visual Objects in a Forced-Choice Paradigm

We introduce a new audio-visual illusion revealing the interplay between audio-visual integration and selective visual attention. This illusion involves two simultaneously moving objects that change their motion trajectory occasionally, but only the direction changes of one object are accompanied by spatially uninformative tones. We observed a selective increase in perceived object speed of the audio-visually synchronized object by measuring the point of subjective equality in a forced-choice paradigm. The illusory increase in perceived speed of the audio-visually synchronized object persisted when preventing eye movements. Using temporally matched color changes of the synchronized object also increased the perceived speed. Yet, using color changes of a surrounding frame instead of tones had no effect on perceived speed ruling out simple alertness explanations. Thus, in contrast to coinciding tones, visual coincidences only elicit illusory increases in perceived speed when the coincidence provided spatial information. Taken together, our pattern of results suggests that audio-visual synchrony attracts visual attention towards the coinciding visual object, leading to an increase in speed-perception and thus shedding new light on the interplay between attention and multisensory feature integration. We discuss potential limitations such as the choice of paradigm and outline prospective research question to further investigate the effect of audio-visual integration on perceived object speed