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 gaping crater of the 1932 QuizapÃº eruption (left-center) lies below the summit of Cerro Azul stratovolcano. Cerro Azul was constructed to the south of its twin volcano Descabezado Grande, where this photo was taken. Steep-sided Cerro Azul has a 500-m-wide summit crater that is open to the north. QuizapÃº was the source of one of the world's largest explosive eruptions of the 20th century in 1932. This eruption created a 600-700 m wide, 150 m deep crater and ejected 9.5 cu km of dacitic tephra. Photo by Oscar GonzÃ¡lez-FerrÃ¡n (University of Chile).