On Tuesday, it was Dow Jones Industrial Average components IBM and United Technologies , and their disappointing quarterly results and listless outlooks, that did in the bulls, with that composite falling by 181 points; Yesterday, it was another Dow heavyweight, iconic technology stalwart Apple Inc. , which held any market strength at bay. This morning, it appears to be a listless revenue and earnings report from heavy equipment maker Caterpillar that may put some pressure on the Dow.