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.
Image Credit: NASA. Asked by Jon Gray. An impact basin known as Valhalla is Callistoâs largest crater with a diameter of over 300 kilometres (190 miles), while concentric rings that surround it extend out to 3,000 kilometres (1,900 miles) â nearly large enough for the entire USA to fit within its boundaries.