The logger includes means for storing how long the operative is subjected to vibrations.

A wireless data logger receives and transmitting transmits the collision information from the information acquisition unit through wireless communication.

Each work queue comprises a queue monitor, an exception monitor, a pool of worker threads, a logger, and a data queue.

An apparatus for monitoring asthmatic conditions takes the form of a data logger for attaching to a spacer.

The monitor (14) preferably includes a logger which can be connected to a host computer which data can be transferred over an external communications link.