Dan Ariely on the psychology of financial risk taking [short video].
Sandra Aamodt and Sam Wang on will power:
In psychological studies, even something as simple as using your nondominant hand to brush your teeth for two weeks can increase willpower capacity. People who stick to an exercise program for two months report reducing their impulsive spending, junk food intake, alcohol use and smoking. They also study more, watch less television and do more housework. Other forms of willpower training, like money-management classes, work as well.
John Derbyshire's profile of Leonhard Euler and his mathematics
It was in this period of the later 1730s that he produced some of his best-known work. In 1736, for example, he published a famous paper solving the problem of the bridges of Königsberg (see opposite page). The central part of that Prussian city (now Russian and called Kaliningrad) was on a large island, where two branches of the Pregel River diverged. Seven bridges connected the city’s various parts, and there was much speculation by the citizens as to whether one could make a complete tour of the town and return to the starting point, crossing each of the seven bridges exactly once. Euler proved that this could not be done. His paper, in which he developed a formula for determining the number and layout of different routes from one point to another, is regarded as the beginning of modern graph theory, a major branch of mathematics critical to the design of modern networks and circuits.
And a bit later:
The famous Euler equation eiπ+1=0 manages to establish a correlation among five of the most important numbers (0, 1, i, e, and π—the last three all owe their symbols to Euler!) as well as among three key operations (addition, multiplication, and exponentiation).
How about some funky ideas for toilet paper?