The pathogenesis of ectopic gastric mucosa is a matter of debate between a congenital-embryological-and an acquired origin-consecutive to a gastroesophageal reflux (GER) like Barrett's esophagus -, the most commonly accepted theory being that these areas are embryological remnants.
Standard size latex filled helium balloons stay afloat for approx 8 - 12 hours, metallic helium filled balloons float for 2-5 days. I have found that a 36 latex helium filled balloon can stay afloat for a number of days due to the thickness of the balloon and the massive quantity of helium.
1 Foil balloons last for 3 to 5 days â sometimes longer as the technology as improved in recent years. They can be refilled by taking them to your nearest helium balloon retailer.  Latex balloons filled with helium typically float for only 8 to 12 hours. The gas escapes through small pores in the latex.