Text: Both the Las Vegas Aerial Gunnery School (which became Nellis Air Force Base and the Nevada Test Site) in the north, and Basic Magnesium in the nearby town of Henderson, arrived in the early 1940s as a result of America's war effort.
Entailment: The las Vegas Arial gunnery school arrived in the early 1940s.
Contradiction: America has never been a part of a war, and as such, has little need for basic magnesium.