Continuous positive airway pressure (CPAP) machines are used to maintain an open airway in patients diagnosed with obstructive sleep apnea. The machine functions by blowing pressurized air into the airway via mask at a setting determined by sleep study and prescribed by a physician.
Also the second largest impact structure on Earth, the 1.85 billion years old Sudbury crater in Canada, hosts world-class mineral deposits - in this case nickel-rich minerals that were melted and concentrated by the extreme heating caused by the impact.
âAt the beginning we were concerned it could be leading up to an eruption.â. Area of outstanding natural beauty: The Yellowstone caldera (circled in red) in Wyoming is the world's largest super-volcano. Scorched earth: An artist's interpretation of how the Midway Basin in the park might look after an eruption.