I just read about a new app for the iPhone that I plan to get. It uses complex formulas predicting your circadian rhythms. It also calculates when you need to be exposed to light and when to avoid light after changing numerous time zones. The app is called Entrain, but unfortunately the article I read doesn’t say where you go to become a Beta tester. I travel a lot, to Europe and to Canada each year, and I am hopeful this app can shorten the time that I am affected by jet lag.