A small note on variation in segmentation annotations

We report on the results of a small crowdsourcing experiment conducted at a workshop on machine learning for segmentation held at the Danish Bio Imaging network meeting 2020. During the workshop we asked participants to manually segment mitochondria in three 2D patches. The aim of the experiment was to illustrate that manual annotations should not be seen as the ground truth, but as a reference standard that is subject to substantial variation. In this note we show how the large variation we observed in the segmentations can be reduced by removing the annotators with worst pair-wise agreement. Having removed the annotators with worst performance, we illustrate that the remaining variance is semantically meaningful and can be exploited to obtain segmentations of cell boundary and cell interior

Efficient performance simulation of class D amplifier output stages

Straightforward simulation of amplifier distortion involves transient simulation of operation on a sine wave input signal, and a subsequent FFT of the output voltage. This approach is very slow on class D amplifiers, since the switching behavior forces simulation time steps that are many orders of magnitude smaller than the duration of one period of an audio sine wave. This work presents a method of simulating the amplifier transfer characteristic using a minimum amount of simulation time, and then deriving THD from the results

A Case with Severe Endometriosis, Ovarian Hyperstimulation Syndrome, and Isolated Unilateral Pleural Effusion after IVF

We present a very rare case of right-sided isolated pleural effusion in a patient with severe endometriosis who, in relation to in vitro fertilization (IVF), developed ovarian hyperstimulation syndrome (OHSS). Earlier laparotomy showed grade IV endometriosis including endometriotic implants of the diaphragm. The patient had no known risk factors for OHSS and only a moderate number of oocytes aspirated. She received, however, repeated hCG injections for luteal support. The patient did not achieve pregnancy but was hospitalized due to pain in the right side of the chest and dyspnoea. A chest computed tomography (CT) showed a pleural effusion on the right side. Total of 1000 ml of pleural fluid was drained after a single thoracentesis. After three days, the symptoms and fluid production ceased. Ascites is a common finding in OHSS, but pleural effusions are rare. Further, isolated pleural effusions have not previously been described in a patient with endometriosis. We suggest that the repeated hCG injections induced effusions from the endometriotic lesions at the diaphragm and as a consequence this patient developed isolated hydrothorax