US President Donald Trump has signed a revised version of his controversial travel ban. The policy, issued on 6 March, exempts citizens of Iraq and people who were issued US visas before 27 January — including those with green cards. Like the first order, which Trump signed on 27 January, the revised policy bars citizens of Iran, Libya, Somalia, Sudan, Syria and Yemen from entering the US for 90 days. Many scientists affected by the first policy have struggled to understand whether it is safe for them to leave the United States to visit family, attend scientific conferences or conduct research. The revised policy might not offer these people much comfort. There are many scientists whose movements will still be restricted under the new ban, which takes effect on 16 March. Among them are researchers who need to renew their visas, or those who are working or studying in the United States on a single-entry visa.

To know more, click Impact of Travel Ban on Science.