India, Aug. 21 -- Harvard University is advising international students and scholars to consider being in the United States before September15, when a sweeping Department of Homeland Security rule is scheduled to replace the long-standing "duration of status" system with fixed periods of admission for F-1 and J-1 visa holders.

The Harvard International Office said students and scholars already in the US when the rule takes effect will receive different treatment from those who leave the country and return after September 15, Harvard Crimson reported. The warning has particular significance for international students planning fall travel, as re-entry after the effective date could place them under the new framework.

The final DHS rule, p...