Since the discourse community itself is intangible, it is easier to imagine discourse communities in terms of the fora in which they operate. The hypothetical journal and email list can each be seen as an example of a forum, or a concrete, local manifestation of the operation of the discourse community.
Daily nausea can be caused by stress. An ulcer in the small intestine may cause chronic nausea. Excessive consumption of caffeine can cause nausea. A person may develop chronic nausea in relation to a peptic ulcer. Indigestion is one of the most common causes of nausea.
Vomiting (throwing up) and diarrhea (frequent, watery bowel movements) can be harmful because they can cause dehydration. Dehydration occurs when you lose too much fluid. Vomiting and diarrhea can be caused by a number of things, including viruses, bacteria, parasites, certain medicines, or certain medical conditions. Foods that are hard to digest (such as too many sweets) and undercooked (raw or partially raw) meat or fish can also cause vomiting and diarrhea.