Police form a perimeter around the road leading to the Mandalay Bay Resort and Casino after a gunman killed 59 people and injured more than 500 others when he opened fire Sunday night on a country music concert in Las Vegas.
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Alzheimer's disease causes atrophy of brain tissue. The discovery that lymph vessels near the brain's surface help remove waste suggests glitches in the lymph system might be involved in Alzheimer's and a variety of other brain diseases.
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Shayna Zerbe, right, instructs Garret Sloan on how to fire a fully automatic machine gun in 2014 at Machine Guns Vegas. Nevada's gun laws are lax compared to other states, and gun tourism is nearly as ubiquitous in Las Vegas as gambling and stage shows.