A post here a few weeks ago discussed the late Luna B. Leopold and his work on the shapes of rivers. I mentioned in that item that Leopold collected data on a small stream called Watts Branch, near Washington, DC. The statement was correct, but I identified the wrong Watts Branch. There are two of […]

I’ll be giving a talk at Towson University later this week. Details here. If you’re in the Baltimore area, please come by.

Scientists are selfless seekers after truth, unswayed by worldly emoluments, immune to the tawdry enticements of fame, indifferent to prizes and honors. Thus I can’t quite imagine why anyone would bother ranking a collection of scientific papers by applying the algorithm that Google uses to decide which Web pages deserve the most prominent display. Nonetheless, […]

A thought for the day:

Our federal income tax law defines the tax y to be paid in terms of the income x; it does so in a clumsy enough way by pasting several linear functions together, each valid in another interval or bracket of income. An archeologist who, five thousand years from now, shall unearth […]

The new issue of American Scientist is up on the Web, and the print edition will soon be delighting readers everywhere. My Computing Science column in this issue of the magazine revisits a famous bit of mathematical folklore—the story about young Carl Friedrich Gauss confounding his boorish schoolmaster. In one popular version of the story, […]

Several posts here (1, 2, 3, 4) as well as my March–April column in American Scientist have looked at technologies for building reversible computing machines. Most of the discussion focuses on “combinational” logic—networks of devices that have no feedback loops or memory elements. In a purely combinational circuit, the state of the outputs is determined […]