Dozens of mainland U.S. universities are helping Puerto Rican students continue their studies while the island recovers from last September's Hurricane Maria, but islanders worry they'll stay away too long.

Brown University is among more than a dozen schools where Puerto Rican students are studying for free. Others include New York University and Tulane University. Many more are offering reduced tuition rates typically granted to in-state residents.

It's modeled after similar work to help students displaced by Hurricane Katrina in 2005.

But some professors in Puerto Rico worry the offers will permanently draw some of the island's best students to the U.S. mainland.

Some students who have come to the mainland vow to return home after this semester, but some hope to keep studying here.