A personal digital assistant 901 stores personal information in an electronic and transportable from. This invention uses an ion exchange process to remove and concentrate the thorium. Appropriate corrective action as necessary is taken to protect the building from damage caused by insects such as termites. A surface acoustic wave filter has an input terminal coupled to the output terminal of the secondary side of the transformer. A device is determined that performs an operation that, at least partially, implements the first of the plurality of events. The physical interface includes in at least one of the surfaces that receives a memory device external to the mobile device.