And there have been periodic efforts over the years to cleanse the tax code of breaks inserted to benefit particular industries, companies and even individuals.

The undercover sweeps - part of a three-year, citywide crackdown - are the latest in a series of efforts against prostitution, including periodic efforts focusing on the prostitutes' customers.

It was annexed by Thailand in 1902, but there have been only periodic efforts to integrate it into the cultural and economic mainstream of the country.

The Government says periodic efforts in the United States Congress to reopen the issue of asylum for Vietnamese in the camps have hampered that effort.

Despite periodic efforts to integrate military units, the Commanders recruit largely from regional tribes.

The Christmas night explosion at the Moores' home in Mims, southeast of Orlando, went unsolved despite periodic efforts by law enforcement to revisit the case.

From this time until 2004, MTV made some periodic efforts to reintroduce pop rock music videos to the channel.

Though the company has made periodic efforts to unload Talisman, a new management team is determined to make a deal as soon as possible.

The boys waited anxiously in the observatory, with Tom making periodic efforts to sight Nestria through the space prober or contact the crew there.

The organization calls such gatherings its "Orientation on the Road" - periodic efforts to inform non-Manhattanites about its many services as well as to urge them to organize.