We report simultaneous meteor echo observations using the Arecibo 430MHz and 46.8-MHz radars. Using identical data-taking and meteor selection criteria, 1868 and 367 meteors were found in the 430-MHz and 46.8-MHz beams, respectively, while 145 were found in both beams during the 7 hours of observation. Of the 367 VHF echoes, there were only 10 trail echoes, while the rest were head echoes, whic...

To evaluate the coherent saturation effects of continuous optical processing using optical coherent transients we studied the time dependence of the photon echoes stimulated by probe fields with constant amplitudes and durations comparable to the coherent dephasing time. The propagation directions of the long echoes were also found to be different from brief pulse echoes. Echoes in the non-caus...

Ficuax 1. Two-dimensional echocardiogram stop frame images are shown above and accompanying schematics below. Left panel demonstrates an apical image with four heart chambers. Middle panel shows cloud of echoes from peripheral injection of normal saline solution demonstrating simultaneous appearance of echoes in all four chambers. A similar injection postoperatively demonstrates echoes in right...

This paper proposed an efficient approach, for weather Radar image classification and filtering, which is based on the combination of the textural analysis and support vector machine (SVM). Since the images are formed by two kinds of echoes, precipitations (rainfalls) and ground echoes (clutter), caused by earth's surface, thus, our purpose is to preserve precipitations and eliminate ground ech...

Talker echoes are one of the influencing factors which need to be addressed during migration of telecommunication towards wideband transmission. A recently carried out talking and listening test (TALT) focusing on wideband echo disturbances is introduced and the results are summarized. The E-Model, a planning tool for telecommunication networks, considers the degradation of the speech quality c...

Theory The proposed sequence is shown in Figure 1. The basic idea is to obtain a spin echo (SE) and a stimulated echo (STE) with different T1 weighting for T1 calculation. In contrast to the FastPACE technique, both echoes were acquired separately. Then, only magnitude images are required which allows for exploiting the Half Fourier technique and using phased array coils. Acquisition of the tru...