Senate leaders say they have reached a bipartisan deal to avoid a doubling of low-interest rates on federally subsidized student loans. The rates were reduced to 3.4 percent in 2007 but were set to double for new loans on July 1 unless Congress intervenes. Under the agreement, federal subsidized student loan rates would stay at 3.4 percent for another year, with funding come from increased premiums on federal pension insurance. In a concession to Republicans, part-time students would now see limits on the number of years they can receive subsidized loans.