Diagnosis. Your doctor can often diagnose dehydration on the basis of physical signs and symptoms. If you're dehydrated, you're also likely to have low blood pressure, especially when moving from a lying to a standing position, a faster than normal heart rate and reduced blood flow to your extremities.
A Corporal is a noncommissioned officer, whereas a Specialist is not. Unlike other NCO ranks (such as Sergeant, Staff Sergeant, etc.), promotions to Corporal don't have to be DA approved (although they can be), since it's considered a lateral promotion, with no changes made to pay.
Corporal is a military rank in use in some form by many militaries and by some police forces or other uniformed organizations. Within NATO, each member nation's corresponding military rank of corporal is combined under the NATO-standard rank scale code OR-4. However, there are often differences in how each nation (or Service in each nation) employs Corporals. Some militaries don't have Corporals, but may instead have a Junior Sergeant.