Stocks closed higher on the final day of the first quarter, buoyed by dovish comments from Fed Chair Janet Yellen. She described the U.S. economy and labor market as far from healthy, suggesting the Fed's low interest rate policy will persist for some time. Weekend talks between the U.S. and Russia failed to resolve the crisis in Ukraine, though both sides recoiled from escalating tensions. Traders describe ongoing sector rotation as healthy. Jane Searle spoke to Jason Weisberg at the NYSE.