[MUSIC PLAYING]

CARL AZUZ: Wrapping up the week for "CNN 10," I'm Carl Azuz.

We're starting today's show in the South American nation

of Brazil, which is trying to come to grips with the worst

mining disaster in its history.

We told you on January 28 how the collapse

of a dam at an iron mine sent a flood of mining debris and mud

into the city of Brumadinho.

The number of people who died from the incident

has risen to 150.

And Brazil's government says at least

182 others are still missing.

Rescue officials do not think they're

going to find any more survivors,

according to the British Broadcasting Corporation.

It also reports that Vale, the company that owns the mine

says it followed recommended safety procedures.

But this is the second mine owned by Vale

where a dam has collapsed.

The other incident happened in the same region

in 2015, killing 19 people and polluting the environment.

And as the Reuters news organization reports,

a Brazilian state official recently

blamed the same problem for both disasters.

Parts of the dam, which was made of dried mud and sand,

turned into liquid, causing the structure to fail.

In addition to the lives lost, the collapse

contaminated a river downstream with mining

debris, waste, and toxins.

And observers say the resulting pollution from that could

indirectly impact millions.

There's a growing challenge facing China, specifically

the future of its economy.

And it's a consequence of the Communist government's

controversial one-child policy.

In the late 1970s, the world's most populated country

wanted to slow down the growth of that population.

So it instituted a policy in 1980 that

limited families to one child.

In some cases, it forced couples to stop having children.

The program ended in 2016.

Chinese families are now allowed to have two children.

But the results of the limit mean

fewer children are alive to support

the country's aging population.

MATT RIVERS: This is a brutal trudge for a healthy person.

But for 68-year-old Qin Taixiao, stricken with emphysema

and cancer, it's near torture.

He keeps warm by burning firewood.

It's cheaper than coal.

QIN TAIXIAO: [SPEAKING CHINESE]

MATT RIVERS: What can I say, he says.

Life's all right.

There's no other way.

That steely stoicism is common in China's

rural villages, where life has only gotten tougher.

Young people have been largely swept

away by the relentless current of China's urban migration.

Qin's children left for work years ago.

He and his wife, Sun Sherong, carry on alone.

FAN MENG: [SPEAKING CHINESE]

MATT RIVERS: It's difficult for our children to care for us,

she says.

We don't want to become a burden.

150 miles away in Beijing, it a burden that 32-year-old

Fan Meng knows well.

She and her husband financially support both their parents,

the four grandparents of their five-year-old daughter,

Qi Shuanrun.

She likes to ski and she enjoys diving, Fan says.

If those are her interests, we have to support her.

And that all costs money.

The village couple and their city counterpart

are a microcosm of China's aging problem.

Simply put, there are a lot more older people

in China than younger ones.

And an aging population, along with greater life expectancy,

can have drastic consequences.

Less working age people might limit the government's

ability to pay for the benefits needed by its aging population.

National economic priorities will shift more towards health

care and pension obligations.

And it might also hurt consumer spending,

with the combined effect of slowing China's economic growth

potential way down.

The obvious solution here is to have more babies.

But that's not happening.

There were 2 million fewer births in 2018.

And most studies agree that China's population

will soon begin to shrink.

The government knows this, and in 2016, changed

the notorious one-child policy.

Couples are now allowed to have two babies per family.

And there's speculation the Communist

Party could erase any restrictions

as soon as this year.

But for families like Fan Meng's, that doesn't matter.

FAN MENG: [SPEAKING CHINESE]

MATT RIVERS: For me, she says, one baby is enough.

One baby is what I can afford in terms of both energy and money.

Not wanting more kids is a nationwide trend

that's unlikely to change, with higher

costs and more opportunities for women as two reasons why.

Back in the village, Qin Taixiao and his wife

survive on about $1,500 per year selling corn.

At some point, though, hauling 50 kilos of wood twice a day

will be too much and his meager income not enough.

They'll need help, just like all of China's older citizens.

Whether there will be enough young people to support

them is one of Chinese society's great questions.

Matt Rivers, CNN, Beijing.

CARL AZUZ: "10-Second Trivia."

Nicolo Amati, like Antonio Stradivari,

became famous for his work with what?

Paintings, fountains, instruments, or bridges.

Some of the greatest violins ever made

are associated with the Amati and Stradivari families.

Some of their violins are said to be acoustically perfect.

But it's not known what makes them that way.

Encyclopedia Britannica says some

believe it's in the instruments' mysterious varnish.

Others say it's a combination of that,

plus the thickness and condition of the wood.

There's a project going on that uses

modern technology to carefully document their historic tones.

[PLAYING BACH CELLO SUITE #2 ON VIOLA]

BARBIE LATZA NADEAU: Few things compare to the sound

of a virtuoso playing.

But this is no ordinary instrument.

It's an Amati viola from the 17th century.

And it's being played here in Cremona, where

music-making is an art form.

[MULTIPLE RECORDINGS PLAYING]

These instruments are displayed in the town's renowned violin

museum, Renaissance and Baroque masterpieces

made by legendary artisans like Stradivari and Amati,

who created many of the first violins, violas, and cellos

as we know them today.

No one makes string instruments like this anymore,

which were created to delight the royal courts of Europe.

And the unique sound they create can't be replicated either.

Maestro Fausto Cacciatori is in charge

of taking these precious instruments out of their museum

cases and down to the auditorium, where

their sound can be recorded.

FAUSTO CACCIATORI: [SPEAKING ITALIAN]

BARBIE LATZA NADEAU: My dream is that these instruments that we

are conserving will be played in 200 or 300 years time

and that the sound is just like we hear today, he says.

[PLAYING VIVALDI "FOUR SEASONS" ON VIOLIN]

Two tech companies have teamed up

to immortalize the notes of these centuries-old instruments

into a sound bank to do just that.

THOMAS KORITKE: We record everything

you can perform on the violin, but not

as part of a musical performance,

but basically bit by bit, one by one.

So we are recording long notes, short notes,

just broken down into very tiny pieces and elements

of the performance.

BARBIE LATZA NADEAU: Once the recordings are finished,

software developers will be able to use the notes and tones

for their own compositions.

But it takes complete silence in order

to carry out these recordings the tower had to cooperate.

They've closed the street with cobblestones

to traffic in order to try to limit

the vibrations and reverberations

inside the recording studio.

The project creators believe the sacrifices will pay off.

LEONARDO TEDESCHI: It will be something

that will allow the digital composer to make music.

And it will be a very practical tool.

But it will never be like having a live musician.

BARBIE LATZA NADEAU: Barbie Latza Nadeau for CNN, Cremona.

[PLAYING VIOLIN]

[ROCK MUSIC PLAYING]

CARL AZUZ: A family reunion gets a 10 out of 10 today.

But it's a family that's a little odder

than you're used to.

Literally, a little otter.

It was found earlier this week by a commercial fisherman

after the pup became separated from its mother.

Officials recorded the pup's cries

and then played them over a speaker

so the mother could hear.

After they located her, they tossed the pup in.

And after a few moments, she pops up to get her baby.

Her baby's light in the water, so you can't say she

forgot her.

Though a fisherman had caught her, Momma Otter had begot her.

And it's clear that she had sought her,

so that when the man had brought her,

it turned any otter day to a special motter's day.

So if you catch one, don't play possum.

Find the mom and then just toss him.

It's a sample an example of how Fridays are awesome.

I'm Carl Azuz.

And that's "CNN 10."

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