7 things to know now: Democratic convention starts; Wasserman Schultz is out; 2 dead in nightclub shooting

Here's a roundup of news trending across the nation and world today.

What to know now:

1. Nightclub shooting: According to Fort Myers, Fla., police, at least two people were killed and 17 others injured in a shooting at a Florida nightclub. The shooting happened overnight at the Club Blu in Fort Meyers, police say.

2. Democratic Convention starts: It's the  first day of the Democratic National Convention. Hillary Clinton will make history by being the first woman in history to accept a major party's nomination for president of the United States. The four-day event will not be without  controversy, as supporters of Sen. Bernie Sanders have already taken to the streets of Philadelphia –where the convention is being held – to protest Clinton's nomination and the way the party selected the former first lady, senator  and secretary of state.

3. Wasserman Schultz is out: Debbie Wasserman Schultz announced Sunday that she will be resigning her post as head of the Democratic National Committee. The announcement, less than 24 hours before the start of the Democratic National Convention, comes on the heels of the release of emails that show DNC  staffers favored Hillary Clinton over Sen. Bernie Sanders in the Democratic primaries. According to media reports, Wasserman Schultz talked to both Clinton and President Obama before announcing her resignation which takes effect Friday.

4. Verizon to buy Yahoo: Verizon will announce Monday that it plans to buy Yahoo. The deal is estimated to be in the $4.8 billion range. Verizon will acquire Yahoo's   internet business and some real estate.

5. Germany bombing: A 27-year-old Syrian refugee exploded a bomb outside of a music festival in Ansbach, Germany Sunday, killing himself and injuring 12 others. The man had been denied asylum in Germany a year ago, reports say. It is the fourth attack in Germany in less than a week.

And one more

A 10-year study on the effectiveness of computerized brain training in cutting the risk of dementia among healthy adults has revealed some good news. It appears the program cut the risk of dementia by 48 percent, U.S. researchers said Sunday at the Alzheimer's Association International Conference in Toronto. Until now, researchers had said they doubted whether computer-based "brain games" had any effect on cognitive function.

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