11.   That worries lab officials, who say U.S. nuclear bombs may deteriorate over time and must be tested to ensure they still work.

12.   The arrest four days ago of Miguel Rodriguez Orejuela, the alleged leader of the Cali cocaine cartel, has also worried intelligence officials.

13.   The efficiency of such a system worries health officials because it allows diseases to spread outside of small groups of partners.

14.   The fact that the problem manifests itself as the sun goes down has NASCAR officials worried about the night truck race scheduled in June.

15.   The majority of Haqqania students come from Pakistan itself, a fact that also worries officials in Washington and Moscow and New Delhi and Jerusalem.

16.   The prospect of a sharp drop in lobster landings particularly worries state officials because lobstering has already absorbed many fishermen from other faltering fisheries.

17.   The Russian arms connection worries officials in Colombia, as Russian criminal groups have become a worldwide power in the years since the breakup of the Soviet Union.

18.   The sharp decline in computer applications among such major schools worries officials at the National Science Foundation, which works to encourage students to enter math and science fields.

19.   The specter of both events converging on Atlanta at the same time has Comdex officials worried.

20.   Their market growth, however, worries officials because Colombian heroin is not only cheaper, but also purer, than the old Southeast Asian variety.