A monolithic double-wavelength semiconductor laser diode is provided in a DVDCD compatible player to suppress deterioration in the optical characteristics of a reading light spot. The invention system is based on the recombination of transfected sequences by FLP, a recombinase derived from Saccharomyces. Air from the aircraft area adjacent to the air mixer is conveyed through the open emergency air flap into the aircraft cabin. The aim of the invention is to raise the rigid roll-bar system into the respective rigid positions in a kinematically simple, forcibly guided manner. In one embodiment, the invention features a compound of formula I: .