Method and apparatus for monitoring event occurrences, e. A second separate confinement heterostructure is on the active region and one or more epitaxial layers is on the second separate confinement heterostructure. The floor care appliance has two liquid storage tanks located in the housing wherein one of the liquid storage tanks generally overlies the other liquid storage tank. Another embodiment of the first plurality of blades in which the blades end or truncate at a radial distance substantially less than the radial distance of the blade shoulder section from the center of the drill bit.