TOP 100 SCIENCE SITES
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| Scientists: We've cracked wheat's genetic code By RAPHAEL G. SATTER 2010-08-27T16:13:36ZLONDON (AP) -- British scientists have decoded the genetic sequence of wheat - one of the world's oldest and most important crops - a development they hope could help the global staple meet the challenges of climate change, disease and population growth.... hosted.ap.org |
Gamers 'better decision makers' Research has shown that action video game fans are better at making quick, accurate decisions than non-gamers. bbc.co.uk |
Archaeologists find theater box at Herod's palace By AISHA MOHAMMED 2010-09-21T22:21:49ZJERUSALEM (AP) -- Israeli archaeologists have excavated a lavish, private theater box in a 400-seat facility at King Herod's winter palace in the Judean desert, the team's head said Tuesday.... hosted.ap.org |
Smarter Than You Think: Google Cars Drive Themselves, in Traffic Google has been working on vehicles that can drive themselves using software. feeds.nytimes.com |
The Physics of Wet Dogs Dog owners no longer have to lay awake at night, wondering how rapidly a wet dog should oscillate its body to effectively shed water onto its favorite human. Presumably, dogs already know, and now, thanks to slo-mo photography, physicists know, tooDog owners no longer have to lay awake at night, wondering how rapidly a wet dog should oscillate its body to effectively shed water onto its favorite human. Presumably, dogs already know, and now, thanks to slo-mo photography, physicists know, too. Which means that everyone who is taking physics courses should pay particular attention to this video because your professor is going to ask you to explain this on your upcoming final exam. Drying of wet fur is critical to mammalian heat regulation. In this fluid dynamics video, a Georgia Institute of Technology research team captures how rapidly hairy/furry mammals must oscillate their bodies when shaking to shed water droplets. High-speed videography and fur-particle tracking shows the angular position of the animal's shoulder skin as a function of time. X-ray cinematography is used to track the motion of the skeleton. The team found that hairy mammals shake their bodies to remove water at frequencies between 4 and 30 Hz, with smaller mammals shaking faster than larger ones: a mouse shakes at 27 Hz, a rat at 18 Hz, a labrador retriever at 4.3 Hz, while a grizzly bear shakes at 4Hz. "Shake frequencies asymptotically approach 4Hz as animals grow in size," they conclude.Not surprisingly, they also found that the looseness of the animal's skin increases the amplitude and speed of shaking. "[It's] nature's analogy to the spin cycle of a washing machine," the authors write. Interestingly, the best fit for this data is not R^0.5 as they predicted. Instead the universal rule for shaken fur is that the frequency increases with R^0.75, suggesting that their model is missing an important correction factor."Perhaps the fur makes a difference?" the team proposes in their video. Sources:Andrew Dickerson, Grant Mills, Jay Bauman, Young-Hui Chang, & David Hu (19 October 2010). The Wet-Dog Shake. Fluid Dynamics : arxiv.org/abs/1010.3279Downloadable video: arxiv.org/src/1010.3279v1/ancAdditional information: the physics arXiv blog.GrrlScientistguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |