Cinco de Mayo is an annual celebration held on May 5 to celebrate Mexico's victory over the Second French Empire at the Battle of Puebla in 1862, led by General Ignacio Zaragoza. Zaragoza died months after the battle from an illness, however, and a larger French force ultimately defeated the Mexican army at the Second Battle of Puebla and then occupied Mexico City. Following the end of the American Civil War in 1865, the United States began lending money and guns to the Mexican Liberals, pushing France and Mexican Conservatives to the edge of defeat. At the opening of the French chambers in January 1866, Napoleon III announced that he would withdraw French troops from Mexico. In reply to a French request for American neutrality, the American secretary of state William H. Seward replied that French withdrawal from Mexico should be unconditional.

In computer programming jargon, a heisenbug is a software bug that seems to disappear or alter its behavior when one attempts to study it. The term is a pun on the name of Werner Heisenberg, the physicist who first introduced the uncertainty principle, and it is a reference to the observer effect, which states that the act of observing a system inevitably alters its state. In electronics, the traditional term is probe effect, where attaching a test probe to a device changes its behavior. The term has been criticized because it confuses Heisenberg's uncertainty principle with the observer effect in quantum mechanics, which are two different concepts. Continue reading →