PORTLAND, Maine (AP) — A Maine native is donating $100 million to Northeastern University to establish a graduate school and research center in Portland. The center will be known as the Roux Institute in honor of benefactor David Roux, who grew up in Lewiston, Maine, and built a fortune as a Silicon Valley investor. The goal is propel the economy in Maine’s biggest city and in the region by making it a technology hub. Ten companies, including retailer L.L. Bean, specialty insurer Unum, pet diagnostics company Idexx and the Jackson Laboratory, have signed on as founding partners.