Job seekers lined up at McDonald's restaurants nationwide last week, hoping to fill one of the fast-food chain's 50,000 openings during a one-day nationwide hiring event. Justin Sullivan/Getty Images hide caption

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Gas prices in April in Washington, D.C. reach $5 a gallon. Karen Bleier/AFP/Getty Images hide caption

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President Barack Obama waves from Air Force One before taking off from Reno, Nev., Thursday. Pablo Martinez Monsivais/AP hide caption

itoggle caption Pablo Martinez Monsivais/AP

Many businesses no longer shut down at dusk — and workers often face a sleep deficit as they fit into different shifts. Here, a Chinese broker sleeps on her desk at the Shanghai Stock Exchange. China Photos/Getty Images hide caption

itoggle caption China Photos/Getty Images