Spectrum characteristics analysis of microseismic signals transmitting between coal bedding

This study was performed to investigate the propagation law of microseismic signals transmitting along the direction parallel and vertical to the bedding in the process of coal rock rupture under uniaxial compression. Microseismic signals during the whole process of coal-rock deformation fracture until burst failure was tested by using the coal rock rupture microseismic experimental system. The empirical mode decomposition graphic, Hilbert spectrum and time-frequency spectrum were obtained by using Hilbert-Huang Transform or HHT. Also the microseismic signals transmitting along the direction parallel and vertical to the bedding in the process of coal rock rupture were spectrum comparative analyzed with EMD analysis method. Results show that amplitude and velocity of microseismic signals changed very small along the parallel direction to bedding in the process of propagation, but microseismic signals delayed and amplitude weakened obviously along the vertical direction to bedding. Signal delay and signal attenuation were confirmed that bedding impact on microseismic wave transmitting.     

Antibiotic resistome mostly relates to bacterial taxonomy along a suburban transmission chain

• The α-diversities of resistome were lower in manure and compost than in soils. • There were significant correlations between the resistome and bacterial taxonomy. • Bacterial taxonomy was the highest in explaining resistome variances. Antibiotic resistance genes comprising antibiotic resistome are of great concern due to their increase in the environment. Recent evidence of shared resistomes between soils and animal husbandry has imposed potential risks to human health. However, the correlation between a given community’s resistome and bacterial taxonomic composition is controversial. Here, a transmission chain of resistomes from swine manure to compost and compost-amended soil were analyzed in five suburban areas of Beijing, China, with unamended agricultural soils as control soils. Antibiotic resistomes and bacterial taxonomic compositions were distinct between (I) manure and compost; and (II) compost-amended and control soils. In manure, compost, and compost-amended soils, the β-diversity of the resistome and bacterial taxonomic composition was significantly correlated, while no correlation was detected in control soils. Bacterial taxonomic composition explained 36.0% of total variations of the resistome composition, much higher than environmental factors. Together, those results demonstrated that antibiotic resistome was closely related to bacterial taxonomic composition along the suburban transmission chain.