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6 March 2014 1:04 pm ,
Vol. 343 ,
Considered an icon of conservation science, researchers at World Wildlife Fund (WWF) headquarters in Washington, D.C.,...
The new atlas, which shows the distribution of important trace metals and other substances, is the first product of...
Early in April, the first of a fleet of environmental monitoring satellites will lift off from Europe's spaceport in...
Since 2000, U.S. government health research agencies have spent almost $1 billion on an effort to churn out thousands...
Magdalena Koziol, a former postdoc at Yale University, was the victim of scientific sabotage. Now, she is suing the...
Antiretroviral drugs can protect people from becoming infected by HIV. But so-called pre-exposure prophylaxis, or PrEP...
Two studies show that eating a diet low in protein and high in carbohydrates is linked to a longer, healthier life, and...
- 6 March 2014 1:04 pm , Vol. 343 , #6175
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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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