In the present work we investigate receptivity and disturbance amplification behind a circular roughness element in a zero-pressure-gradient flat-plate boundary layer with the aim to identify and understand the basic mechanisms at work. The low disturbance background and the high repeatability of the direct numerical simulations allow to evaluate the different contributions of acoustic-roughnes...

This paper presents the H/V ratio peak amplitude and frequency, their correlation with the site frequency and amplification factor, and limitations. The basin-edge and flat-layer models with different types of soils in the surficial layer were simulated using 2.5D (two and half dimensional) modeling. The effects of sediment bedrock velocity contrast on the H/V ratio peak frequency and amplitude...

Importance of Pressure Pulse Amplification in the Association of Resting Heart Rate and Arterial Stiffness To the Editor: The study by Whelton et al1 shows that resting heart rate is independently associated with arterial stiffness. Arterial stiffness was quantified as distensibility and determined from ultrasound measurements of carotid diameter and MRI measurements of aortic diameter. Distens...

[1] The ionospheric heating facility of the High Frequency Active Auroral Research Program (HAARP) has been used extensively in the last 3 years for injection of ELF/VLF waves into the magnetosphere via modulated heating of the overhead auroral electrojet currents. Of particular interest are waves that are observed to be nonlinearly amplified after interaction with hot plasma electrons in the E...

[1] Previous studies have suggested that Arctic amplification has caused planetary-scale waves to elongate meridionally and slow down, resulting in more frequent blocking patterns and extreme weather. Here trends in the meridional extent of atmospheric waves over North America and the North Atlantic are investigated in three reanalyses, and it is demonstrated that previously reported positive t...