Rather than cooling the brain by the relatively slow heat conduction through the low heat conductivity of the bony skull and hair covering the head, the present invention teaches the use of a light weight, easily applied neck encircling collar in firm contact with the soft tissue of the neck, and particularly in good thermal contact with the carotid arteries traversing the neck. Load is sensed by recognition of the distance between two components of the car, one which remains relatively fixed regardless of the weight of the car, the other which moves relative to the first component as the car weight changes. The intrinsic part of the base region includes a first portion having a first doping concentration and a second portion having a second doping concentration lower than the first doping concentration. A computing unit outputs as a measurement a flow rate obtained based on the output Vh in a flow rate region where a flow rate is larger than a predetermined boundary flow rate, and outputs as a measurement a flow rate obtained based on the output Vout in a flow rate region where it is less than a boundary flow rate.