One of the Crescent City’s time-honored traditions -- a steaming bowl of Yak-a-mein Soup, a.k.a., “Old Sober” -- after a night of partying in the French Quarter actually does have a basis in scientific fact. That was the word today from an overview of the chemistry of hangovers, presented as part of the 245th National Meeting & Exposition of the American Chemical Society, the world’s largest scientific society.