(CNN) New research suggests the cognitive effects of marijuana use, though significant, may not persist for very long in young people. Here's what else you need to know to Get Up to Speed and Out the Door . (You can also get "5 Things You Need to Know Today" delivered to your inbox daily. Sign up here .)

1. President Trump

President Trump thinks he can do great things in a meeting with North Korean leader Kim Jong Un. But he's also more than willing to walk away . Speaking at Mar-a-Lago with Japanese Prime Minister Shinzo Abe, the President said that if talks with Kim aren't "fruitful, I will respectfully leave the meeting." Abe during the visit reminded Trump about past US failures in North Korean interactions.

Meantime, Trump downplayed talk he's getting ready to fire special counsel Robert Mueller or Deputy Attorney General Rod Rosenstein; "They're still here," he said. When questions turned to Russia, he used his go-to phrase -- "no collusion" -- FIVE times . Speaking of Russia, senior administration officials told CNN the President personally made the decision to dump the plan to hit the Russians with more sanctions after the Syria chemical weapons attack. Trump also is facing backlash for using the word "breeding" when discussing cities that don't cooperate with the feds to deport undocumented immigrants.

2. Puerto Rico blackout

Puerto Rico just can't catch a break. Almost the entire island is in the dark this morning, after a crew removing a fallen tower got too close to an energized line, causing it to fail and, in the process, knock out power across the grid. Only a fraction of residents have regained power so far. This is the second blackout in two weeks caused by the same subcontractor, so the island's governor wants its public power agency to cancel its contract. Huge swaths of Puerto Rico have been without power since Hurricane Maria destroyed its electrical grid last fall, making that the second-longest blackout in history

3. Cuba

The man likely to become Cuba's next President may not carry the Castro name, but he'll uphold the Castro ideology. Cuban First Vice President Miguel Diaz-Canel was nominated by the country's National Assembly to replace Raul Castro as the island nation's leader. He's a 57-year-old technocrat who said he believes "in continuity," dashing the hopes of those wishing that a change in leadership could lead to reforms. And Raul Castro is still expected to exercise a large measure of control over the Cuban government.

JUST WATCHED The challenges facing Cuba's likely new leader Replay More Videos ... MUST WATCH The challenges facing Cuba's likely new leader 02:38

4. Syria

Chemical weapons experts still haven't been able to get into Douma, the site of a suspected gas attack on civilians. The latest delay was caused by gunfire on a UN security team . It's not clear now when the team of experts from the Organization for the Prohibition of Chemical Weapons will be allowed into the city. And that's concerning because there's fear all the physical evidence of an attack might be gone by the time a team gets in. About 75 people were killed in the attack, for which Syria and Russia were blamed. The US, UK and France retaliated last week with missile strikes.

JUST WATCHED An American ISIS widow looks for a way home Replay More Videos ... MUST WATCH An American ISIS widow looks for a way home 05:10

5. Airline safety

JUST WATCHED Passenger: I tried and tried to pull woman in Replay More Videos ... MUST WATCH Passenger: I tried and tried to pull woman in 01:11

Editor's note: We're grateful to our readers who are aviation experts and who pointed out a line in yesterday's newsletter that implied the pilot regained control of the plane only after it dropped from about 30,000 feet to 10,000 feet. It's We're grateful to our readers who are aviation experts and who pointed out a line in yesterday's newsletter that implied the pilot regained control of the plane only after it dropped from about 30,000 feet to 10,000 feet. It's standard procedure in an emergency to descend to 10,000 feet, which is what the pilot, who's being praised for her "nerves of steel," did.

JUST WATCHED Pilot praised for her handling of emergency Replay More Videos ... MUST WATCH Pilot praised for her handling of emergency 02:41

BREAKFAST BROWSE

Super Spielberg

Looks like Steven Spielberg is joining the superhero craze. He's getting involved in "Blackhawk," from the DC Universe.

Welcome to Wakanda

Saudi Arabia ended it's 35-year ban on movie theaters with a screening of "Black Panther."

JUST WATCHED Kids see themselves in 'Black Panther' heroes Replay More Videos ... MUST WATCH Kids see themselves in 'Black Panther' heroes 01:50

Remember me?

He needed a kidney and made a desperate plea. Thankfully, a classmate he hadn't seen in five decades answered the call.

Reboots roll on

Tips wanted

That "Three Billboards" movie was inspired by an actual cold case , and police just doubled the reward in the real-life mystery.

Tumbleweed trouble

Living the California lifestyle is awesome -- until giant tumbleweeds roll into town and darn near take over.

HAPPENING LATER

Prince death investigation

A Minnesota prosecutor will announce today whether anyone will be charged in pop legend's April 2016 death.

TODAY'S NUMBER

100 million

The number of Amazon Prime members, revealed for the first time by CEO Jeff Bezos in a letter to shareholders

JUST WATCHED Is Amazon a monopoly? Replay More Videos ... MUST WATCH Is Amazon a monopoly? 04:14

TODAY'S QUOTE

"This action goes against our very foundation."

Air National Guard Director Lt. Gen. Scott Rice, after three members of the Tennessee Air National Guard were fired or demoted after one used a dinosaur puppet while taking the reenlistment oath

AND FINALLY

What's Michael Scott's superpower?