I have recently started paying attention to my iPhone 4 beeping/vibrating at least once a day without any new notification/message/email. I also started keeping a record of the time it happens and it is around 12.13 PM everyday. I asked a few other iPhone users and they seem to have the same kind of problem around the same time. Does anyone know why this happens? Is it due to some app I installed? I checked all my apps which have push notifications and I was not able to find any culprit.