Hey. Hope you had a great weekend and thank you for taking 10 minutes to get up to speed on current events.
I'm Carl Azuz for CNN STUDENT NEWS.
First up, a papal trip across the sea.
Pope Francis travelled from the Vatican to the Caribbean nation of Cuba over the weekend.
This is a significant visit.
Pope Francis is the leader of the Roman Catholic Church.
It's the largest denomination of the world's largest religion, Christianity.
And for decades, Cuba's government has been officially atheist.
It's had a number of restrictions on religion.
The pope said that the Catholic Church was once an important part of Cuban history and he called for Cuba's government to give people the freedom, the means and the space to practice their faith.
He also called on Cuba to open itself to the world.
The pope's visit included a mass with tens of thousands of people yesterday and a private meeting with Cuba's former leader Fidel Castro.
The pontiff plans to spend today travelling through Cuba and then fly to the U.S. capital tomorrow.
Like Cuba, China is a communist country.
A recent study suggests measures like that and perhaps more are needed.
It found that 87 out of 91 former NFL players had CTE.
Well, first of all, CTE, chronic traumatic encephalopathy is a brain disease.
It's a progressive brain disease for which we have no known treatment, no cure.
And frankly, it's not something that we even knew about until seven or eight years ago.
Research in this really began about in 2008.
I had a chance to visit the lab in 2011 where the science is taking place where they were examining the brains of former NFL players and other people as well.
Now, this most recent study says 96 percent of people whose brains were examined had evidence of the CTE.
Now, I want to make something clear here.
These are people who probably during their lives worried that something was wrong and donated and had their brains donated to science after they died.
So, there was already some concern about it.
There's no way to suggest that 96 percent of all NFL players will develop CTE, but there is obviously a lot of science here.
And when you look at the brains of these people, what they found were these protein deposits that were very similar again to what you might see with Alzheimer's disease.
In life, these people often had anger issues, depression, and memory loss.
Those are three that sort of constellation of symptoms that people often develop and it was often younger players whose brains are still developing that may have been most at risk.
CTE is not limited to athletes.
Anyone with repeated head trauma and concussions could develop it.
As far as football goes, researchers don't know why some players develop CTE and others don't.
But engineers are joining the effort to make the game safer.