If you put a scientist in charge of your academy, you'll get twice as many scientist graduates as normal.
If you put in a scientist with at least a 20% bonus, all the graduates will also be slightly higher quality (they'll roll twice for attributes, taking the better one)... although there's a good chance that scientists will be in the same field as whoever you appointed.
Edit: bah, ninja'd by Droll. I'll post anyway, since I've got some extra information.