The present invention refers to dyestuffs of the general Formula wherein R, X, Y and Z are defined as given in claim 1, dyestuff mixtures and hair dye compositions comprising them, as well as a process for colouring hair. A database stores data of various tissue types and target temperatures that are allocated to these various tissue types. If the value is smaller than its corresponding value in a neighboring frame, the neighboring frame’s corresponding value is used instead of the value of the current frame. In a preferred embodiment, the system receives a channel signal, detects a program start or stop marker within the signal, and controls the EPG or the recording device to perform acts corresponding to the detection of a start or stop instruction. The positive electrode material is composed of particles having a composition represented by the general formula: LiaCobMgcAdOeFf, and magnesium, the element A and fluorine exist uniformly in the vicinity of the surfaces of the particles.