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.
Only around 180 impact craters have ever been discovered on Earth and around 30 per cent of them contain important natural resources of minerals or oil and gas. The largest and oldest known crater prior to this study, the 300 kilometre wide Vredefort crater in South Africa, is 2 billion years in age and heavily eroded.
Image caption The Tamu massif is comparable in size to Olympus Mons on Mars. Scientists say that they have discovered the single largest volcano in the world, a dead colossus deep beneath the Pacific waves. A team writing in the journal Nature Geoscience says the 310,000 sq km (119,000 sq mi) Tamu Massif is comparable in size to Mars' vast Olympus Mons volcano-the largest in the Solar System.