Doppler ultrasound is a type of ultrasound that depends on the Doppler Effect, a change in the wave's frequency, which can occur from the motion of a reflector, such a red blood cell. We experience the Doppler Effect when, for example, an ambulance approaches us, passes and then drives away.
Definition of PLACODERM. : any of a class (Placodermi) of extinct chiefly Devonian fishes with an armor of bony plates and primitive jaw structures.ADVERTISEMENT. New Latin Placodermi, ultimately from GK plak-, plax + derma skin â more at derm-. any of a class (Placodermi) of extinct chiefly Devonian fishes with an armor of bony plates and primitive jaw structures. ADVERTISEMENT.
POLYPLACOPHORA (Alternate name: Loricata). (poly-plac-o-phor-a (lor-i-cat-a)) Latin meaning: poly = many plac = plate phor = carry, i.e.: bearer of many plates. The polyplacophorans, commonly known as chitons, are often considered by scientists to be the most primitive of all existing molluscs.