The triple turreted castle has been in use by the Corps of Engineers since it was adopted in 1840. Prior to that time an insignia of a similar design was worn on the uniforms of the Corps of Cadets of the United States Military Academy since the Academy was under the supervision and direction of the Chief of Engineers.
The most common cause of energy crisis is a drop of cerebral perfusion (global ischemia), usually resulting from cardiac arrest or severe hypotension (shock). Sustained severe hypoglycemia, and seizures lasting 1-2 hours also cause permanent brain damage. Pure hypoxia in clinical settings is unusual.
The heart has three coronary arteries, two of them large, branching arteries that deliver oxygenated blood to the heart muscle. If one of these arteries or branches becomes blocked suddenly, a portion of the heart is starved of oxygen, a condition called cardiac ischemia. If cardiac ischemia lasts too long, the starved heart tissue dies. This is a heart attack, otherwise known as a myocardial infarction -- literally, death of heart muscle.