A cup holder of rotary type has a holder part provided on a back face of a lid body. The perpendicular magnetic recording medium includes: a lower structure; and a recording layer formed on the lower structure, wherein the recording layer has a balancing force 2\u03c0Mr2K1 of 0. The measuring transducer comprises an oscillation exciter as well as at least one oscillation sensor. For baseball training, the mat is placed in the batters box such that the pivot device is facing the rear. The invention more particularly relates to a process comprising a stage of liquidliquid extraction of an aqueous solution comprising acetic acid and to a stage of distillation of the extract obtained.