This report describes a spectrum of M-mode and cross-sectional echocardiographic abnormalities in eight patients with infective endocarditis of the tricuspid valve. The M-mode echocardiogram of the tricuspid valve was abnormal in all but one patient in whom abnormal echoes were seen anterior to the tricuspid valve, in the right ventricular cavity and right ventricular outflow tract. Six patient...

Weather radar data quality control is extremely important for meteorological and hydrological applications. For weather radars, scatterers in the atmosphere are not only meteorological particles like cloud, rain drops, snowflakes, and hails, but also non-meteorological particles such as chaff, insects, and birds. For radar meteorologists it is a major issue and challenge to design numerical sch...

Transducer side lobes consist of multiple low-intensity sound beams located outside of the main ultrasound beam. Although the echoes generated by side lobes originate outside of the main beam, they appear as specular or diffuse artifactual echoes within the beam. They are visible with both static and real-time equipment. Specular side-lobe artifacts occur near strong, curved, highly reflecting ...

In this paper we propose two metrics for the evaluation of the impact of pre-echoes and post-echoes on the perceived quality in soundfield rendering applications. These metrics are derived from psychoacoustic-based considerations, in particular the masking effect, well known in the literature of perceptual coding. The measurement is accomplished through a virtual microphone array that samples t...

Delay-Doppler mapping continues to be the most widely used imaging technique in radar astronomy. Various methods have been devised to partition echoes in delay-Doppler space for different degrees of echo dispersion (as quantified by the overspreading factor ). These include the standard interpulse/intercode methods for underspread ( ) or slightly overspread ( ) echoes, intrapulse methods for gr...

Milan et al. (2001) identified a class of narrow, slow-moving HF radar backscatter echoes which originate between altitudes of 80 and 100 km, the ionospheric Dand lower E-regions. These echoes appeared to be associated with the occurrence of pulsating aurora, which are known to be created by energetic electrons capable of penetrating to D region altitudes. In this study we show that these echoe...

Echolocation, while a useful skill for visually impaired people, is difficult to learn because humans naturally suppress environmental echoes. However, if the echoes are enhanced compared to environmentally normal echoes, they may therefore help to ease echolocation learners into the learning process. Blind and sighted participants discriminated enhanced echoes in two 2-interval forced choice (...

Glasses display a wide array of nonlinear acoustic phenomena at temperatures T ≲ 1 K. This behavior has traditionally been explained by an ensemble of weakly coupled, two-level tunneling states, a theory that is also used to describe the thermodynamic properties of glasses at low temperatures. One of the most striking acoustic signatures in this regime is the existence of phonon echoes, a featu...

The capability of satellite radar altimeters to monitor the height changes of major lakes is well established. However, river systems present far more challenging targets. By retracking altimeter echoes using an expert system approach, river heights can be successfully monitored; this capability is bounded by the along-track sampling rate. However, a glimpse into the potential of future altimet...