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.
Flooded volcanic craters constitute the countryâs largest bodies of water: Lakes Coatepeque (15 square miles [39 square km]), Ilopango (40 square miles [100 square km]), and Olomega (20 square miles [52 square km]). Lake Coatepeque, one of the largest of a line of flooded volcanic craters in western El Salvador.