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27 November 2013 12:59 pm ,
Vol. 342 ,
The new head of the National Center for Science Education promises to "fight the good fight" against attacks on...
Analyses of the H7N9 strains isolated from four new cases show that the virus is evolving rapidly, heightening anxiety...
In 2009, Jack Szostak shared a Nobel Prize for his part in discovering the role of telomeres, the end bits of...
Science has exposed a thriving academic black market in China involving shady agencies, corrupt scientists, and...
Paper-selling agencies flourish in the aura of reputable businesses. For some scientists, it may be difficult to tell...
Data collected by satellites and floating probes have chronicled a 2-decade rise in the temperature and thickness of a...
Cholesterol, the artery-clogging molecule that contributes to cardiovascular disease, has another nasty trick up its...
Until recently, the Defense Advanced Research Projects Agency (DARPA) kept its plans for its $70 million portion of the...
- 27 November 2013 12:59 pm , Vol. 342 , #6162
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Video: Scales Give Sharks Their Speed
9 February 2012 3:12 pm
Shark skin may be de rigueur poolside at the 2012 Summer Olympics. A new study finds that microscopic scales known as denticles propel the predators through the water at speeds 12% faster than they would otherwise achieve without them. To fish out how this happens, researchers mounted pieces of shortfin maco (Isurus oxyrinchus) and porbeagle shark (Lamna nasus) skin on flexible robotic fins and placed them in a tank. By analyzing water flow over the skin, the team found that denticles determined the proximity of swirls of water, called vortices (visible in the video), to the fin. Intact denticles produced swirls close to the skin, the researchers report in The Journal of Experimental Biology, creating low pressure areas that pulled the fin forward. Fins with their denticles sanded off produced vortices further away from the skin, reducing fin flapping speeds. The scientists note that manufacturers of Olympic-worthy swimwear, designed with dimples to reduce drag, may want to build in little ridges instead.
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