The Massachusetts Convention Center Authority reports that shows at the Boston Convention and Exhibition Center and the John B. Hynes Veteran Memorial Center have been kept on track, in spite of the chaotic events following last week's bombings at the Boston Marathon. The Ambulatory Surgery Center Association's annual meeting, which began last Wednesday, saw only a 5 percent drop in attendance from what had been projected. Registration for the nearly 15,000 people attending the Experimental Biology annual meeting took place in the satellite hotels, including the Westin Boston Waterfront and the Renaissance Boston Waterfront on Friday, and the event began on time on Saturday. "We are grateful to our customers and their attendees for their patience throughout a week of uncertainty and constantly changing information," said James E. Rooney, executive director of the MCCA. "I continue to be impressed with the resiliency of the meetings industry and our customers' willingness to work with use to keep their meetings scheduled." Boston Comic Con, which was scheduled to open at the Hynes on April 20, has been postponed. Increased security measures have been put in place at both facilities.