An exposure method and apparatus exposes a substrate that is loaded on a stage via a carrier system, with an exposure beam via a projection optical system and a liquid. A bias current provided to the laser device may be changed while changes in the output power of a light signal from the laser device is monitored. When performing a transaction involving information cards, a generic card selector, using a selector policy engine, can identify a card selector to use for the transaction. The cooling channels are disposed in the end portion, being parallel to the outside face of the end portion so that they open out into the tip of the end portion towards the free end of the blade. A subset of the chains is selected to form a basis for the directed set.