You ought to take a look at this article on the LifeHacker blog: “Naps Can Seriously Improve All-Day Learning.” Here’s an excerpt:
Taking a 90-minute nap the day of a test or presentation sounds like a ludicrous luxury. But a recent study on the brain’s ability to recall facts found that napping at noon could mean a lot more brain power at 6 p.m.
Here’s the link:
Here’s a link to a similar recent article in Scientific American:
www.scientificamerican.com/podcast/episode.cfm?id=to-learn-better-sleep-on-it-10-02-24
and one in Medical New Today: www.medicalnewstoday.com/articles/180304.php