What Is an Automated External Defibrillator? An automated external defibrillator (AED) is a portable device that checks the heart rhythm and can send an electric shock to the heart to try to restore a normal rhythm. AEDs are used to treat sudden cardiac arrest (SCA). SCA is a condition in which the heart suddenly and unexpectedly stops beating.
curl. 1  to form into coils or ringlets, as the hair. 2  to form into a spiral or curved shape; coil. 3  to adorn with, or as with, curls or ringlets. 4  to grow in or form curls or ringlets, as the hair. 5  to become curved or undulated. 6  to coil. 7  to play at the game of curling.
Curl The curl of a vector field, denoted or (the notation used in this work), is defined as the vector field having magnitude equal to the maximum circulation at each point and to be oriented perpendicularly to this plane of circulation for each point. More precisely, the magnitude of is the limiting value of circulation per unit area.