Rachel Bateman, 9, has braces to correct an overbite. Her orthodontist opted not to use expanders to expand her upper arch. Mike Ruocco/NPR hide caption

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This computer illustration shows a kidney stone in the renal pelvis. Although a major component of kidney stones is calcum, a new study shows that a calcium-rich diet may help inhibit their development. 3D Clinic/Getty Images hide caption

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Keeping an active mind by doing things like playing chess helps stave off the development of dementia. Bulent Kilic/AFP via Getty Images hide caption

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A supporter of the Spanish team cries while watching the World Cup final soccer match, which Spain won 1-0.  Crying may have evolved as a signal to those who were in close physical proximity to us, but it also adds a powerful dimension to interpersonal communication Dani Pozo/AFP/Getty Images hide caption

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Owen Levine, 3, helps make a broccoli and pineapple pizza for Meatless Monday. Colleen Levine hide caption

itoggle caption Colleen Levine

Mary VanDam pours coffee for patron Jim Brumm at Mr. B's Pancake House in Laketon Township, Mich. Cory Morse/Muskegon Chronicle via AP hide caption

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Scientists thought that people with stronger taste sensations would have needed less salt. TooFarNorth/Flickr hide caption

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Youth teams play on an auxiliary outdoor rink before the 2010 New Year's Day Winter Classic NHL hockey game. New research shows that young players in leagues that allow checking are much more likely to suffer concussions and serious injuries than kids who play in leagues that ban it. Elise Amendola/AP hide caption

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New studies show that getting enough sleep can improve performance in academics and athletics. iStockphoto.com hide caption

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