Abstract: In chemical structure of a fulgide type photochromic compound having the following general formula; ##STR1## introduction of electron donative groups into its heteroaromatic structure is effective in improving the long wave length sensitivity without any lowering in its thermal stability. Thanks to such combined functional properties, the products are advantageously used for optical recording media, copying media, printing media, optical filters and display materials.

Abstract: A gear shifting system for an automotive vehicle equipped with an internal combustion engine comprises a load sensor for sensing the shift load generated by a shifting motion of a driver or a rider, a power adjusting system for adjusting the engine power of the internal combustion engine, and a control unit for controlling the power adjusting system. The control unit is actuated in response to a signal from the load sensor when the sensed load is equal to or greater than a predetermined value, and outputs a control signal to the power adjusting system so as to adjust the engine power. The load sensor is assembled on a linkage system connected between a shift shaft of the power transmission and the shift pedal, so that the load sensor can detect a stretching load or a depressing load caused by shifting operation in the shift-up or shift-down mode, and for differentiating between them.