A process for greatly improving the color index of polyhydric alcohols, especially trimethylolpropane, by hydrogenation comprises using, in the hydrogenation, an alcohol which has already been purified by distillation. In one case it is quaternary ammonium derivative of a heteropolyacid. Therefore, it is possible to effectively set a touch-lock area on the touch screen and thus to prevent the mobile terminal from performing an operation against the will of a user. A coupler is provided that can be disengaged by axial pressure and arranged at a distance from the first end. Such a method comprises administering to the subject a composition comprising an oligopeptide having activity in reducing urea concentration in the subject’s serum as determined by a mouse renal reperfusion test, wherein the oligopeptide comprises the sequence AQG or MTRV, AQGV or LAGV. Embodiments quantify the frequency selectivity in a channel by measuring the variation in a particular channel statistic across sub-carriers in an OFDM system, involve minimal complexity in implementation, and can be used in a variety of scenarios.