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.
The deep volcanic crater, top, was produced by the eruption of Mount Tambora in Indonesia in April 1815 - the most powerful volcanic blast in recorded history.Credit Iwan Setiyawan/KOMPAS, via Associated Press.Continue reading the main story.he deep volcanic crater, top, was produced by the eruption of Mount Tambora in Indonesia in April 1815 - the most powerful volcanic blast in recorded history. Credit Iwan Setiyawan/KOMPAS, via Associated Press. Continue reading the main story.