A first transmitter transmits symbols. The second region is formed by removing the insulating film by machining. The procedure includes obtaining history information on a type of an operation performed to each of a plurality of files, calculating a priority for a file among the files based on the type of the operation in the history information, and selecting a file among the files based on the priority. The nut shaped platform preferably includes a threaded bore to receive a fastener used to releasably attach a handle to the shaft. The sheets are thereafter folded, sheet-by-sheet, and collected into a stack. A preferred layered double hydroxide is one that has layers which comprise LiAl26+.