Techniques to tie a processor power state transition on a platform to another power state transition on the platform. 11 gcm3; the density of the wax in the liquid state is not more than 0. Uses displacement measuring means for two directions in space, each parallel to the writing surface, and comprising means to establish an US waves path between an US transmitter and an US receiver; means to measure changes in the phase of the received signal, and for computing the displacement. In use, the processor is adapted to determine the temperature of the fluid from the sensor and, provide an indication of this via the indication device. The sampled physiological measures are evaluated.