What Is Obesity Hypoventilation Syndrome? Obesity hypoventilation (HI-po-ven-tih-LA-shun) syndrome (OHS) is a breathing disorder that affects some obese people. In OHS, poor breathing results in too much carbon dioxide (hypoventilation) and too little oxygen in the blood (hypoxemia). OHS sometimes is called Pickwickian syndrome.
Click on photo for a larger picture. In the photo above, I am holding two small vials of liquid metal. The vial on the right contains gallium, an element that melts at 29.76Â° Celsius (85.57Â° Fahrenheit). The vial on the left is an alloy that contains gallium, indium, and tin, and melts at -20Â° Celsius (-4Â° Fahrenheit). The gallium is liquid because I had the bottle in my shirt pocket, next to my warm body.
Why is the melting point of gallium metal so low? Gallium metal is somewhat anomalous because it's melting point is very low (Tm = 303 K) but its boiling point is relatively high Tb = 2477 K. That is say that its liquid state has got a very large stability range. Also its pressure variation of melting point is negative. My hand-waving explanation is that Ga has several competing structures that have almost the same energy close to its melting temperature and therefore just below Tm the solid transforms continuously from one structure to the other competing structures and therefore melts.