NYU's epic land grab has suffered some defeats of late: This winter, the University's campaign to set up a massive high-tech shop on Roosevelt Island was thwarted by Cornell. And, earlier this month, it was forced to scale down its Greenwich Village expansion plan by 16 percent. But today will be a better day for aspiring world leader John Sexton, as Mayor Bloomberg is expected to announce that NYU will be allowed to install its Center for Urban Science & Progress in 370 Jay Street, a Downtown Brooklyn building (or "eyesore") currently leased by the MTA. (An applied-science research institute, the Center's programs will be jointly run by already existing Brooklyn outpost NYU-Polytechnic, Carnegie-Mellon, CUNY, the Indian Institute of Technology-Bombay, the University of Toronto, and the University of Warwick.) The school will have to front $50 million toward the cost of moving the MTA's people and equipment, plus another $10 million to relocate a Police Department office there. In return, the city will chip in $15 million in tax breaks and discounted heating costs for the space. Because this is a science building — and not, say, a liberal-arts one — that lopsided-sounding deal will probably pay off for someone somewhere down the line.