The gallbladder is a small pouch that sits just under the liver. The gallbladder stores bile produced by the liver. After meals, the gallbladder is empty and flat, like a deflated balloon.efore a meal, the gallbladder may be full of bile and about the size of a small pear. In response to signals, the gallbladder squeezes stored bile into the small intestine through a series of tubes called ducts. Bile helps digest fats, but the gallbladder itself is not essential.
U-substitution is for functions that can be written as the product of another function and its derivative. $$\int u du$$. Integration by parts is for functions that can be written as the product of another function and a third function's derivative.
While unix-line-discard is a good mnemonic, the use of CTRL+U as a line-erase character precedes the invention of UNIX. It was used as such on various Digital Equipment (DEC) systems, including the PDP-8. For instance, from my dusty bookshelf I see that CTRL+U was used as line-erase in the PDP-8 Symbolic Editor (page 5-13 of the 1972 edition of the PDP-8 Introduction To Programming (Volume 1) manual published by DEC). In fact, in the early days of UNIX, the @ character was often the default line-erase character.