links for 2009-06-21

"I am in Portland for the day, having dragged myself out of bed at an ungodly hour (4 AM) to catch my flight. (On the plus side, there is almost no traffic on LA freeways at that hour.) The reason: to visit the city's Green Microgym founded by personal trainer Adam Boesel last year. Perhaps you read some of the press coverage the opening generated: Boesel has retrofitted much of his exercise equipment (stationary bikes, treadmills, elliptical machines) so that gym members can produce a little bit of usable energy during their workouts -- not a lot, mind you, but enough to run the fans, for example, or the stereo system. Combine that with other strategies for improving energy efficiency, and Boege keeps his electricity costs to a bare minimum. In time, he thinks he can break even, and maybe even turn a small profit."

"Humorist John Hodgman rambles through a new story about aliens, physics, time, space and the way all of these somehow contribute to a sweet, perfect memory of falling in love. "

"So, why would a bullet curve? For something to change direction of motion, there must be a force acting on it. Instead of calculating the motion of a spinning bullet or something, I am just going to determine the force needed to make a bullet curve. That force can then be compared to other forces like gravity and air resistance."

"[Y]ou might be able to get away with dressing badly for your interview in academic science, especially if your science is really good. But it's no sure thing, so why take a chance? And even if you do get hired, wearing jeans and a T-shirt is unlikely to make a good first impression on someone who, even if they look past your dress-related defects, might file it away and write about it in some future letter of recommendation. Outside the academic environment, such as in interviews for industry or government jobs, your fashion sins are far less likely to be overlooked."

"This web page describes the errors that I have seen most frequently in undergraduate mathematics, the likely causes of those errors, and their remedies. I am tired of seeing these same old errors over and over again. (I would rather see new, original errors!) I caution my undergraduate students about these errors at the beginning of each semester."