By John S. McClenahen Likely reflecting both financial and global political concerns, chief executive officers of more than 100 companies in a variety of industries were slightly less confident about the U.S. economy in the second quarter of this year than they were during the first quarter, according to a survey released by the Conference Board, New York. The business research group's quarterly measure of CEO confidence dropped to 70 points in the second quarter from 73 during the first quarter of this year. Similarly, the executives were slightly more subdued in the second quarter about the short-term economic outlook. While still positive about economic prospects for the next six months, the Conference Board's measure of the executives' short-term outlook fell to 68 points in the second quarter from 72 during the first quarter. A reading of more than 50 reflects more positive than negative responses.