The Germans call it ohrwurm. Here,it's known as the earworm -- the situation when a jingle or song gets stuck in a continuous mental loop and refuses to exit your head. You hear the song over and over and over again. So it is with me and Yael Naim's "New Soul" -- the very addictive sound track to the Macbook Air Commercial. For the past six weeks I have been dealing with this earworm.