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.
Ambergris (/ Ë Ã¦ m b Ér É¡ r iË s / or / Ë Ã¦ m b Ér É¡ r Éª s /, Latin: ambra grisea, Old French: ambre gris), ambergrease or grey amber, is a solid, waxy, flammable substance of a dull grey or blackish colour, produced in the digestive system of sperm whales. Freshly-produced ambergris has a marine, fecal odour.