71.   But a new study by Northern Illinois University, the Latino Institute and the Chicago Urban League casts doubt about how beneficial some new jobs are to some families.

72.   But a closer look at history casts doubt on such a deterministic formulation.

73.   But a new study casts fresh doubts on its effectiveness at high doses.

74.   But AIDS experts were already casting doubts on them.

75.   But a recent report prepared by the Johns Hopkins School of Public Health cast serious doubt on that claim.

76.   But a report last February by the Institute of Medicine, a branch of the National Academy of Sciences, cast doubt on whether cigarettes can be made safer.

77.   But according to the National Weather Service in Chicago, the transition has been less than perfect, with errors and improper procedures casting doubt on snow totals.

78.   But as the injured Patrick Ewing stood in the locker room after the game, he cast doubt on that premise.

79.   But charges that impugn a leading senator and cast doubt on air safety inspections need a full public airing.

80.   But by Friday, the Libyan leadership cast doubt over a deal.