A system and method for circumventing schemes that use duplication detection to detect and block unsolicited e-mail An address on a list is assigned to one of m sublists, where m is an integer that is greater than one. A method for detecting a leak in a piping system is also provided. The sample receiving chip also includes a channel formed in the substrate, the channel configured to collect the aliquot volume of a sample fluid and transfer the aliquot volume of sample fluid to the sample region. Version numbers of the active and inactive versions of the agent code are stored in a reloadable module vector.