5 things you need to know Wednesday

Brexit is on: Britain actually begins its exit

U.K. Prime Minister Theresa May officially triggered Article 50, the legislation that begins Britain’s withdrawal from the European Union, on Wednesday. Britain's notification letter sets off a process in which the EU will respond within 48 hours. Britain will have two years to negotiate the terms of this long-awaited divorce, meaning it will leave the EU by April 2019. The negotiations could be heated. Of particular concern is whether Britain decides to remain in the EU's single market, the borderless trade area that also allows EU citizens to live and work, without a visa, in any other EU country. The government has pledged that it is prepared to give up this crucial trade access as it tries to lower immigration.

Samsung gets ready to unveil the Galaxy S8

Samsung is expected to announce its latest Galaxy device, the Galaxy S8, at an event Wednesday in New York. The launch will be the first major phone reveal since last year's Galaxy Note 7 debacle, so the stakes for success are high. Leaks suggest the new phone will adopt a futuristic design that drops the home button to make almost the entire front a display. USA TODAY will have full coverage of Samsung's event; you can follow along on Facebook and Twitter.

Big day for Trump's proposed wall along the U.S.-Mexico border

Much remains unknown about President Trump's plan to build a wall along the border with Mexico, but initial documents laying out the timeline for bids indicated the government wants to finalize a design and begin awarding contracts as early as May. Wednesday is the deadline for companies to submit prototype designs. The wall, documents show, is envisioned being as high as 30 feet, with automated gates for pedestrians and vehicles. Here’s a look at what’s known and not about plans for the wall and its potential effects on U.S. construction companies and workers.

How much do NCAA basketball coaches get paid?

The NCAA men’s basketball tournament is down to the Final Four. And you probably know that three of the coaches of the remaining teams — Frank Martin (South Carolina), Mark Few (Gonzaga) and Dana Altman (Oregon) — are making their first-ever trip to the Final Four. But what you probably don’t know is how much each of those coaches are paid. On Wednesday, USA TODAY Sports will release its NCAA men’s basketball coaches’ salary database. Here’s a look at last year’s field. We break down what each coach makes and will even pull out some of the most astonishing, must-see perks from the coaches’ contracts.

Early death rate spikes on drug overdoses in suburbs 

Premature deaths soared in 2015, according to a new report released Wednesday from the Robert Wood Johnson Foundation. According to the report, the largest affected group were people aged 25-44.The rate among that group soared in 2015, due in large part to a surge of drug overdoses in suburban areas. Drug deaths were also found to be accelerating among 15- to 24-year-olds, though homicide, suicide and motor vehicle crashes are the leading causes of death for that group. The discoveries are part of the foundation's ranking of counties across the country to better understand how the health of America's communities.

Contributing: The Associated Press