Convolutional Neural Network to Detect Deep Low-Frequency Tremors from Seismic Waveform Images

The installation of dense seismometer arrays in Japan approximately 20 years ago has led to the discovery of deep low-frequency tremors, which are oscillations clearly different from ordinary earthquakes. As such tremors may be related to large earthquakes, it is an important issue in seismology to investigate tremors that occurred before establishing dense seismometer arrays. We use deep learning aiming to detect evidence of tremors from past seismic data of more than 50 years ago, when seismic waveforms were printed on paper. First, we construct a convolutional neural network (CNN) based on the ResNet architecture to extract tremors from seismic waveform images. Experiments applying the CNN to synthetic images generated according to seismograph paper records show that the trained model can correctly determine the presence of tremors in the seismic waveforms. In addition, the gradient-weighted class activation mapping clearly indicates the tremor location on each image. Thus, the proposed CNN has a strong potential for detecting tremors on numerous paper records, which can enable to deepen the understanding of the relations between tremors and earthquakes.

ECMO Challenges and Its Future: Indian Scenario

History of extracorporeal membrane oxygenation (ECMO) in India dates back to 2001. Initially, ECMO was started for postoperative cardiac cases, but from 2008, it was introduced to intensive critical care unit as a regular practice for refractory cardiogenic shock and acute respiratory distress syndrome. Gradually, the utility of ECMO keeps on increasing such as in poisoning, transplant unit, and even in tracheobronchial surgery. Some centers even started using ECMO for extracorporeal cardiopulmonary resuscitation, even though the data is insufficient. In academic field also, ECMO has had great progress in India with three books and numerous paper presentations by Indian authors, regular conferences, and continued medical education. There were lot of challenges in establishing ECMO in Indian scenario which were addressed successfully; a few challenges are still there which need to be addressed pre-emptively. The most common challenges of ECMO were awareness, cost, initiation at right time, outcome, nosocomial infections, and transport. Transport of critically ill patient, especially on ECMO, is risky and also involves lots of cost. To overcome this problem, flying squad was established in 2010 where the team goes to the hospital where the patient is and initiates and manages ECMO there itself. The future of ECMO in India is quite promising, not only with increasing number of cases and centers, but also in terms of cost-effectiveness and technology.

A method for isolating and growing the lepra bacillus of man. (Preliminary note.)

For a number of year different investigators have attempted to cultivate the lepra bacillus of man and the allied organisms found in the rat and other animals. It is not intended in this preliminary note to discuss the numerous paper which have been published from time to time from the various English, Continental, and American laboratories. These papers deal with non acid-fast bacilli, or with acid-fast bacilli growing quickly on ordinary media, which in the opinion of the writer, are contaminating organisms, and not the true lepra bacillus. So far, no one has produced a culture of acid-fast bacilli isolated from a leper, and showing the characters of the lepra bacillus as found in the tissues of man. It was with the object of obtaining a pure living culture of the lepra bacillus that these investigations were undertaken. The material used was the nasal discharge and scrapings from a typical leper. The discharge showed large masses of lepra bacilli and a number of contaminating micro-organisms. Firstly, most of the contaminations were killed by placing the discharge in a 2-per cent. solution of ericolin at 38° C. for one hour as recommended for the isolation of the tubercle bacillus; then cultures were made from the sediment on to different media and incubated at 38° C.