In Britain, it means diddly. It means you're a male, presumably respectable. If you have no other title, then the overly-British will put esq. after your name on an envelope, etc. In America, I believe it's sometimes used after a lawyer's surname. However, I don't see it used much by U.S. lawyers.
Davit systems are most often used to lower an emergency lifeboat to the embarkation level to be boarded. Davits can also be used as man-overboard safety devices to retrieve personnel from the water. The lifeboat davit has falls (now made of wire, historically of manila rope) that are used to lower the lifeboat into the water.
How does a Pulse Oximeter work? A Pulse Oximeter works by shooting light through the area of our body being used for the measurement (lets, assume from now onward that it is a finger) and detecting the amount of light that managed to to through that finger.