Alexa brings a vast amount of skills to its Echos. Add basic home security to the list. With Alexa Guard enabled on a first-party Echo smart speaker, it can use its microphones for good. In this case, ...

Sound is a form of energy. It is that form of energy which makes us hear. Sound wave is a vibratory disturbance in a medium which carries energy from one point to another without there being a direct ...

This was a useful method for detecting tornadoes before the advent of modern Doppler radar systems. A conventional radar transmitter sends out microwave pulses, and when this energy strikes an object, ...

Feb. 25, 2004 — Pulmonary hypertension increases mortality in sickle cell disease, according to the results of a study published in the Feb. 26 issue of the New England Journal of Medicine. Doppler ...

Users of Amazon's video-capable Echo products can now watch video news briefs, check the latest forecast video or even stream the radar from WRAL. Users of Amazon's video-capable Echo products can now ...