81.   The researchers studied women with and without ovarian cancer and found that the women who had ovulated fewer times over their lifetime were less likely to have cancer.

82.   The scientific evidence is inconclusive, but the military is focusing on several potential health hazards, which researchers are studying.

83.   The UCLA researchers did not study for-profit charter schools.

84.   There are no recent studies, largely because corrections officials do not let researchers study the extent of illegal behavior in their institutions.

85.   Treatment had been withheld from black men with syphilis so researchers could study the progress of the disease.

86.   Vaccines to prevent breast cancer from ever developing is another area researchers are studying.

87.   Until the recent epidemic of mad cow disease in England, few researchers studied these diseases, and those who did were unable to isolate an infectious agent.

88.   Users believe the drug is safer than heroine or cocaine, but researchers are still studying its long-term effects on the brain.

89.   Protease inhibitors already are known to increase the risk of diabetes by raising blood sugar, so AIDS researchers are studying whether this new problem is related.

90.   After the morning celebration, Mrs. Bush and several authors were visiting District of Columbia schools where researchers are studying reading instruction.