The characteristics of acoustic echoes from six species of deep-dwelling (up to 400 m) Hawaiian Lujanid snappers were determined by backscatter measurements at the surface. A broadband linear frequency-modulated signal and a short dolphinlike sonar signal were used as the incident signals. The fish were anesthetized and attached to a monofilament net that was attached to a rotor so echoes could...

Nectar-feeding glossophagine bats searching for flowers are guided by their echolocation system as well as olfactory cues in detecting and recognizing nectar sources. Therefore, chiropterophilous plants, which depend on these bats as pollinators, may be expected to have evolved acoustically conspicuous flowers that facilitate detection. As it is poorly understood how bats manage to find and rec...

Weather surveillance radars observe clear-air radar echoes (CAE); aerial biota and irregularities in atmospheric refractive index caused the echoes. Using weak returns of atmospheric CAE, the radars have been applied to wind findings in a short radar range in a fair weather, in particular S-band radars. Long wavelength radars perform good to observe air motion, because a detectable turbulent sc...

Nine patients with anatomically documented vegetations on one or more cusps of the aortic valve had echocardiograms in which abnormal echoes were associated with the aortic leaflet echoes. The motion of the abnormal echoes during systole correlated well with the anatomic location of vegetations: a vegetation on the right coronary cusp moved anteriorly with systole while a vegetation on the nonc...

This study was designed to identify the ultrasound echoes originating from the left ventricle. Injections of indocyanine green and saline were made directly in the left ventricular cavity via a cardiac catheter in patients undergoing routine diagnostic cardiac catheterization. The injections produced a cloud of echoes that filled the left ventricular cavity and outlined the left side of the int...

Photon-echo-based devices have been proposed for many applications in data storage, image processing, and optical communications. Many of these applications would benefit if the output from the photon-echo process could be used as input in a second photon-echo process. We demonstrate the generation of such secondary echoes, using the amplified output from an initial photon-echo process. The amp...