"What is the difference between licensing a patent and selling a patent?"
When a patent is licensed, LSU still holds title to the patent. Only certain rights in the patent are granted to the licensee, under specific terms and conditions. Licensing is somewhat like leasing an apartment. LSU seldom sells a patent. An outright sale changes the ownership, somewhat like selling a home.
"May an LSU employee take a license from LSU?"
Yes, under limited circumstances, provided that the conditions of PM-67 are fulfilled.
"What are licensing fees?"
Initial fees usually due upon execution of a license, and usually not based on sales.
"What are royalties?"
Amounts paid by a licensee, based on the extent to which a patented invention is used. Royalties are often (but not always) a fixed percentage of sales of embodiments of the patented invention.