Can Brain Drain Justify Immigration Restrictions?

Kieran Oberman's research focuses on the ethical implications of international migration.  My thesis, "Immigration and Freedom of Movement", argued that people have a human right to freedom of movement that entails a right to cross borders.  I conceded however that there may be extreme circumstances under which immigration restrictions could be justified.  In my post-doctoral work at Stanford I wish to consider this question of justified restrictions in more detail by focussing on the particular issue of medical brain drain from developing countries.  We know that medical brain can have devastating consequences so it may constitute justified grounds for restriction.  Another area of research I wish to focus on is the treatment of migrants after they have arrived within their state of destination.  I wish to consider, for instance, whether migrants must be granted equal rights to citizens and if so after how long and under what conditions.  The research I shall undertake in these areas will be included in an eventual book project on the ethics of immigration policy.