Acoustic microscopy acoustic microscope (CSAM), and C-mode scanning acoustic microscope (C-SAM). More recently acoustic microscopes based around picosecond ultrasonics systems have demonstrated acoustic imaging in cells using sub-optical wavelengths working with ultrasonic frequencies into the multi-GHz. Since the vast majority of acoustic microscopes in use today are C-SAM type instruments, this discussion will be limited to these instruments. Ultrasound is broadly defined as any sound having a frequency above 20 kHz, which is approximately the highest frequency that can be detected by the human ear. However, the acoustic microscopes emit ultrasound ranging from 5 MHz to beyond 400 MHz so that micrometre
Above the Influence and increases in the perceptions that others use marijuana." In 2011, Ohio State University released the results of an independent scientific study stating that the "Above the Influence" campaign appears to have effectively reduced marijuana use by teenagers. "Evidence for the success of "Above the Influence" is especially heartening because the primary independent evaluation of its predecessor campaign, 'My Anti-Drug', showed no evidence for success", said Michael Slater, principal investigator of the new study and professor of communication at Ohio State University. "The 'Above the Influence' campaign appears to be successful because it taps into the desire by teenagers to