PerformanceDude writes "Bitfloor (a New York-based online exchange for Bitcoin) yesterday made the following announcement on their website: I am sorry to announce that due to circumstances outside of our control BitFloor must cease all trading operations indefinitely. Unfortunately, our US bank account is scheduled to be closed and we can no longer provide the same level of USD deposits and withdrawals as we have in the past. As such, I have made the decision to halt operations and return all funds. Over the next days we will be working with all clients to ensure that everyone receives their funds. Please be patient as we process your request. Roman — bitfloor.com" According to the company's Twitter account, money should be returned to users' bank accounts shortly.

Jörg Sprave's day job is as a manager in the world of consumer electronics. But he has been for many years making manifest the sort of things that once filled my school notebook margins with doodles: slingshots and other devices for launching bolts, steel balls, and other stuff at high speed at targets or just into the air. (Some of his "slingshots" are hard to recognize as such; he eschews the classic American wrist-rocket braced design as well as the old Tom Sawyer forked branch in favor of things a bit more elaborate.) Thanks to the Internet, hobbies that were once obscure are now easy to follow, and Sprave's homemade slingshots are no exception; you can follow his exploits through an ongoing series of YouTube videos and a forum site that builds on these videos. He's doing it in Germany, too, where firearms may be harder to come by than in the U.S., but giant honkin' firecrackers are available (at least for part of the year), and acts accordingly. Amazingly, he has yet to lose an eye; his goggles are a wise precaution. Sprave has agreed to answer your questions about his own take on physics as a hobby. As usual for Slashdot interviews, you're invited to ask as many questions as you'd like, but please divide them, one question per post.

An anonymous reader writes "Early humans were able to move from Africa after a single genetic mutation allowed them to become vegetarians, scientists claim. The switch, which allowed humans to process vegetables, meant that humans were able to move away from water sources and spread across the continent. A team of geneticists compared DNA sequences from a variety of people around the world to see how different populations relate to one another and when they have gone their separate ways. The scientists found that a key genetic variant gave humans the ability to convert fats from plants into essential nutrients for the brain."