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Rats will enthusiastically work to free a rat that is caught in a trap — and it turns out that they are especially eager to be a Good Samaritan when they're in the company of other willing helpers.

But that urge to come to the rescue quickly disappears if a potential hero is surrounded by indifferent rat pals that make no move to assist the unfortunate, trapped rodent.

Almost 40 years have passed since the last time NASA astronauts blasted off into space on a brand new spaceship.

Now, as NASA looks forward to Wednesday's planned test flight of the SpaceX Crew Dragon with a pair of astronauts on board, some in the spaceflight community have a little bit of déjà vu.

In 2006, while hiking around the Root Glacier in Alaska to set up scientific instruments, researcher Tim Bartholomaus encountered something unexpected.

"What the heck is this!" Bartholomaus recalls thinking. He's a glaciologist at the University of Idaho.

The White House has touted the fact that its coronavirus task force provided each state with a list of labs that could potentially test for the virus, but officials in a number of states told NPR that the lists did not actually help them increase testing.

Because of the coronavirus, NASA's top official is asking space fans not to travel to Florida later this month to watch astronauts blast off from American soil for the first time since the retirement of the space shuttles in 2011.

As the coronavirus sweeps across the globe, one pattern remains consistent: Men seem harder hit by the virus than women and are more likely to have severe illness or die.

At least in the United States, however, it seems that men are less likely to seek out testing for the virus when they feel sick.

Tiny bits of twisted plant fibers found on an ancient stone tool suggest that Neanderthals were able to make and use sophisticated cords like string and rope.

Cords made from twisted fibers are so ubiquitous today that it's easy to take them for granted. But they're a key survival technology that can be used to make everything from clothes to bags to shelters.

When researcher Josh Santarpia stands at the foot of a bed, taking measurements with a device that can detect tiny, invisible particles of mucus or saliva that come out of someone's mouth and move through the air, he can tell whether the bedridden person is speaking or not just by looking at the read-out on his instrument.

The World Health Organization says the virus that causes COVID-19 doesn't seem to linger in the air or be capable of spreading through the air over distances of more than about 3 feet.

But at least one expert in virus transmission said it's way too soon to know that.

At a time when the nation is desperate for authoritative information about the coronavirus pandemic, the country's foremost agency for fighting infectious disease outbreaks has gone conspicuously silent.

"I want to assure Americans that we have a team of public health experts," President Trump said at Tuesday evening's coronavirus task force briefing — a bit of reassurance that probably would not have been necessary if that briefing had included anyone from the Centers for Disease Control and Prevention.

It's unclear whether people who recover from COVID-19 will be immune to reinfection from the coronavirus and, if so, how long that immunity will last.

The United States is facing a grim dilemma: either effectively shut down society for months to prevent transmission of the coronavirus or see health care systems overwhelmed by people needing treatment for severe infections.

That's the conclusion of a influential new analysis by a well-respected group at Imperial College London that does computer simulations of outbreaks.

The U.S. government maintains an enormous stockpile of emergency medical supplies, and officials have already started dipping into it to help fight the novel coronavirus.

But while having a stockpile is better than not having it, experts say, there's a limit to what a stockpile can do in this crisis.

Anyone can catch COVID-19, the disease caused by the newly identified coronavirus. But certain populations appear to be more vulnerable to its effects.

Consider the 11 deaths so far in the United States — one in California and the rest in Washington state.

Scientists who use math and computers to simulate the course of epidemics are taking on the new coronavirus to try to predict how this global outbreak might evolve and how best to tackle it.

But some say more could be done to take advantage of these modeling tools and the researchers' findings.

Updated at 10:21 p.m ET

As labs across the United States quickly ramp up their ability to test for the novel coronavirus, public health officials are anxiously awaiting results that could start to reveal its secret movements around the country.

New cases of the coronavirus were identified in at least four states on Sunday: New York, Rhode Island, California and Washington.

Scientists can get very excited about what they study, and that means they can be pretty jazzed when what they study gets turned into one of the official emojis of the world and enters our shared visual language.

But sometimes that enthusiasm is tempered by more complex feelings, which is the case with some of the latest emojis that are about to hit our smartphones.

Consider the "rock" emoji.

NASA is at a critical juncture in its push to get people back to the moon by 2024, with key decisions expected within weeks.

This effort to meet an ambitious deadline set by the Trump administration last year faces widespread skepticism in the aerospace community, even as the new head of human spaceflight at NASA insists that it can succeed.

U.S. officials are weighing the benefits and risks of proposed experiments that might make a dangerous pathogen even worse — but the details of that review, and the exact nature of the experiments, aren't being released to the public.

Later this week, officials are to hold a meeting in Bethesda, Md., to debate how much information to openly share about this kind of controversial work and how much to reveal about the reasoning behind decisions to pursue or forgo it.

Some wolf puppies are unexpectedly willing to play fetch, according to scientists who saw young wolves retrieve a ball thrown by a stranger and bring it back at that person's urging.

This behavior wouldn't be surprising in a dog. But wolves are thought to be less responsive to human cues because they haven't gone through thousands of years of domestication.

Parrots can perform impressive feats of intelligence, and a new study suggests that some of these "feathered apes" may also practice acts of kindness.

African grey parrots voluntarily helped a partner get a food reward by giving the other bird a valuable metal token that could be exchanged for a walnut, according to a newly published report in the journal Current Biology.

An enormous number of tumbleweeds blew onto a road in eastern Washington state on New Year's Eve, piling up into a mountain of tangled branches that blocked traffic and even buried some cars, trapping travelers inside.

"In the 20 years that I have worked here, I have never seen it as bad as this," says Washington State Patrol trooper Chris Thorson. "I've never seen six to eight cars, including a semi-truck, actually stopped and trapped on a highway because of tumbleweeds."

Copyright 2020 NPR. To see more, visit https://www.npr.org.

ARI SHAPIRO, HOST:

Shepherds in Christmas Nativity scenes that were painted, carved or sculpted hundreds of years ago sometimes have throats with large, abnormal growths.

These are realistic depictions of goiter, an enlargement of the thyroid gland caused by iodine deficiency. The condition was common in those days in northern Italy, where the soil and water are depleted of iodine.

Steamboat Geyser, the tallest active geyser in the world, erupted more times in 2019 than in any other year, baffling scientists who are trying to understand what triggered this unusual streak of activity.

The geyser can shoot water more than 300 feet into the air, and this year it has erupted more than 45 times, surpassing the 32 eruptions recorded in 2018.

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