If a vaccine works, then the vaccinators might conceivably set up what's known as ring vaccinations around Ebola hot spots. In this technique, medical workers simply vaccinate everybody in a ring, miles deep, around a focus of a virus.

The dragonfly is an exceptionally beautiful insect and a fierce carnivore. It has four wings that beat independently. This gives it an ability to maneuver in the air with superb dexterity. A dragonfly can put on a burst of speed, stop on a dime, hover, fly backward, and switch direction in a flash. This is a hunting behavior known as hawking.

The annual flight of the dragonflies goes mostly unnoticed, though it is one of the great migrations of flying creatures that occur across North America.

Richard Preston Quotes