Novel phonocardiography system for heartbeat detection from various locations.

The paper presents evaluation of the proposed phonocardiography (PCG) measurement system designed primarily for heartbeat detection to estimate heart rate (HR). Typically, HR estimation is performed using electrocardiography (ECG) or pulse wave as one of the fundamental diagnostic methodologies for assessing cardiac function. The system includes novel both sensory part and data processing procedure, which is based on signal preprocessing using Wavelet Transform (WT) and Shannon energy computation and heart sounds classification using K-means.

Bacterial growth and community composition in fractions of dissolved organic carbon of different molar mass from interstitial water.

The ability of different molar-mass fractions of interstitial dissolved organic carbon (DOC) from a small stream to stimulate bacterial growth was determined. Growth was the greatest in the low-molar mass (<1 kDa) (LMM) fraction and the least in the high-molar mass (>10 kDa) (HMM) one. The LMM fraction consistently had a higher ratio of carbon to organic nitrogen than other fractions.