I'm Carla Zeus.

We're happy to have you watching CNN 10 here on Earth, where most of us live, We spend about 1/3 of every day lying down sleeping and 2/3 standing or sitting in an upright position.

That's not really how it goes in space when people are weightless and the zero gravity environment causes more fluid to shift to the head, faces get puffy legs, lose volume and appear to be smaller.

Many astronauts have complained of I and back problems after coming back down to Earth and its gravity.

And now scientists say they've discovered some new risks with Long term space flight.

A study published recently in JAMA Network Open, a medical journal, examined 11 healthy astronauts who had been on the International Space station for six months.

Eight of them had unusual characteristics observed in their blood.

For instance, six of the astronauts had either stagnant or reverse blood flow from their heads.

The lead author of the study says he doesn't know if that's actually harmful.

The blood's still leaving the head through other pathways so flowing backwards through a jugular vein may not be dangerous, but he says it does show a change in how blood moves through the body while in space.

Another issue, the study found, was blood clots.

One astronaut had one another showed signs of a partial blood clot that is potentially harmful as the clots can block the flow of blood to the lungs.

The astronaut, who had one, was treated for the rest of the space flight and made it home safely.

What does all this mean?

Well, one researcher says, these issues have probably been occurring since humans first ventured into space and that they would likely resolve themselves when astronauts came back down to Earth.

Knowing about them now gives doctors something else to monitor.

When people leave our atmosphere, all schools are shut down.

Today, in the East Asian city of Hong Kong, some university campuses there have become rallying points for protesters who, among other things, have called for more democracy in the city.

Hong Kong is a special administrative region of China, meaning it has more freedoms than the mainland.

But those who've been pro testing for almost six months now are concerned that China's communist government is increasing its power in Hong Kong, and they see Hong Kong's government and police as being aligned with China.

Over the weekend, demonstrators at Hong Kong's Polytechnic University targeted police with gasoline bombs, bricks launched from catapults and bows and arrows.

One arrow hit an officer in the leg.

Authorities fired water cannons and tear gas at protesters, and police say that if the demonstrators continue to use weapons, they'll respond with minimum force and, if they have no other choice, live ammunition.

The violent clashes between police and protesters in Hong Kong turning university campuses into scorched battle grounds.

For five months, demonstrators have been fighting against Beijing's increasing influence over the territory.

They have smashed mainland Chinese banks, vandalized a state run newspaper office and trashed restaurants run by owners who support Beijing.

Once a city, mainlanders flock to for a taste of Western affluence and education.

Many are now fleeing Hong Kong heading back to the mainland, some boarding a police boat to get out.

These passengers took a train across the border into Shenzhen, China.

Several are university students, the violence, abruptly ending their semesters, greeted here with signs like This one, it reads we are one family were with you, the young man holding it as can we not show his face?

Fearing retaliation, he tells us his company's sent him offering temporary housing to mainland Chinese students, leaving their Hong Kong university's way.

Want to help teaser situation a little and give them some warmth?

Hotels and Jen Jen are rolling out the red of welcome home signs the Communist Youth League, run by the Communist Party of China, among the first to step up to assist with the growing exodus of young people, pro Beijing private businesses and alumni networks from Chinese universities also helping the students find a place to stay, this mainland student tells us she left the Education University of Hong Kong after administrators canceled classes last week.

She, like everyone we spoke with, fearful to reveal her identity, experiencing a mix of emotions, fear, confusion, uncertainty, even resentment towards the violent protesters.

They just tried to destroy the normal people's life on it will influence our graduation so really happy.

Back in Hong Kong, we found other mainlanders like Charlie staying put For now.

I think cleaner students are scared, are worried, but I have to say that I cannot see.

Many mean a student targeted by those protesters are booted by those protesters or their local custom.

But his mother still worries.

After seeing the images of destruction, she traveled from the mainland to Hong Kong to check in on her son.

Charlie says early on in the movement actually sympathized with the demonstrators.

I chanced in my mind they need to reduce the violence.

Violence that's led to this campus is that once promoted, dialogue left near empty, shattered, charred residents now cleaning up, wondering what will ignite next.

David Go over CNN, Which of these port cities is located on the coast of the Adriatic Sea.

Venice, Italy.

Palermo, Italy.

Barcelona, Spain.

Or Istanbul, Turkey.

So all these ports are located in the Mediterranean region.

The only one on the Adriatic Sea is Venice, and it was a strong storm system in the Adriatic that contributed to another high tide in Venice on Sunday.

The waters rose to about 59 inches in the lagoon city, which is considered an exceptional high watermark.

But it's still well short of last Tuesday's peak more than 73 inches.

Forecasters don't expect they'll get that high again over the next few days.

High tide on Saturday was actually welcome relief for Venetian.

Struggling with the worst flooding in half a century.

It filled historic ST Mark's square but was not enough to do more damage than already done.

This cafe opened for the first time since Tuesday's high water, Mark said.

More than a foot of water inside, enough to break the dishwasher and the fridge is, waiter told us, never found near Venetians.

Roll up our sleeves and start working again.

Venice is our lady.

We will protect her.

Meanwhile, at ST Mark's Basilica, the water at the door didn't knock before entering.

But it's still got their attention.

Way have a more than this level of water.

It's not uncommon for water to enter the outer atrium.

There's even a special drainage system to handle it.

But Pierpaolo campus Trini says it was just the second time there's been significant flooding in the main chamber.

10 centimeters there and another meter in the crypt.

The water came and went quickly, but the salt in the water stays in the 900 year old walls much longer, eating away at the marble and a brick near the floor and even on the mosaic ceiling.

And that's the damage.

And that's the damage.

Just down the canal, you can still hear the sound of music at one of the most important conservatory's in Italy, but the orchestra's being conducted by students and volunteers working to dry out some 50 meters worth of bookshelves that ended up partially submerged.

But why were they ever on the ground floor?

This could have been easily first question by the problem.

That way, with the this floor off the first floor was not strong enough to keep the weight.

So that's why we have to move them downstairs.

The most valuable books and manuscripts are being packed up, sent away to be frozen to stop the fragile historic pages from deteriorating.

It'll only be thought out when the conservatory has the money to restore them, not anytime soon.

Back.

It's a marks.

They're preparing for their first Mass in almost a week, praying the worst has come and gone as they wait for what's forecast to be another exceptionally high tide on Sunday.

Cleveland, Ohio, is one of hundreds of US locations that recently saw record cold.

For this time of year.

But whoever this is knows how to make the best of it.

It was from the 20th floor of a nearby hotel that a guest recorded a mysterious Spiderman making his mark in an open field.

Why is he mysterious?

Because when the person who got the video went outside to see who it was, the man like a spider had hopped off his Web and into thin air.

Maybe he was feeling reclusive, or he just like using his long legs to go wandering somewhere else.

But I don't Iraq need to say it took a torrential lot of effort to weave such an orb.

Just display.

Imagine what he could have done with eight legs now that would have jumped all over.

The World Wide Web of coral is used for CNN 10.