An terior cerebral artery A1 segment hypoplasia is an uncom-. mon fetal variant of the circle of Willis. The frequency of this. congenital variation is 1â13% as derived from angiograms. and autopsy reports. Impaired collateral blood flow through. the circle of Willis is a recognized risk factor for ischemic. stroke. The A1 segment of the anterior cerebral artery is a. principal supplier of anterior collateral blood flow.
George Washington, 1799. Printer Friendly Version >>>. George Washington finished his second term as the first President of the United States in 1797. Weary of the political infighting surrounding the presidency, he longed for the peace of retirement to his beloved Mount Vernon.
About George Washington, 1st President of the USA. George Washington was born on February 22, 1732, in Westmoreland County, Virginia. Washington served as a general and commander-in-chief of the colonial armies during the American Revolution, and later became the first president of the United States, serving from 1789 to 1797. He died on December 14, 1799, in Mount Vernon, Virginia.