U.S.

How Vine Settled On 6 Seconds

According to numbers released Tuesday, Twitter's one-year-old video-sharing app Vine now has about 40 million registered users. The app lets users shoot a maximum of six seconds per Vine, so we wanted to know why the limit's set at six seconds and not a second longer.

Calls Continue For San Diego Mayor To Step Down

Embattled San Diego mayor Bob Filner and attorneys met Tuesday about his future as the leader of the city. The mayor is under pressure to resign following allegations of sexual harassment by at least 16 women. Meanwhile, a recall petition drive is under way while the mayor's supporters try to counter criticism.

What's Behind The Turnaround At Miami Public Schools?

Alberto Carvalho runs the nation's fourth largest school district — Miami Dade Public Schools. Since he took over four years ago, the district's turnaround has been nothing short of "miraculous", or so his supporters say. During his tenure the dropout rate has plummeted. The high school graduation rate has climbed to record levels and test scores for all students are way up. How did Carvalho do it?