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Thank you. and quote science podcast to receive special offers. Welcome to the science podcast for November 25, 2016.

I'm Sarah Cresby.

In this week's show, newswriter Sam Keane joined Alexa Billo to discuss scientists at work the night shift as part of a special

issue on circadian science. And David Grimm is here with the roundup of stories from our daily

news site. Support for the science podcast is provided by Triple AAS, the American Association for the science podcast is provided by AAAS, the American Association for the Advancement of Science and its members.

Find AAAAS, the Science Society, at www.aAAS.org.

Now we have David Grimm, editor for our daily news site.

He's here to talk about some recent online stories.

First up, we have a story on watching cement dry.

So we're just going to sit here while you listen to us watch cement.

Actually, we're going to talk about how cement. Right. Okay.

Actually, we're going to talk about how cement isn't as harmful as previously thought.

Dave, what kind of harms can cement possibly cause?

There's two things cement does that are bad for the environment.

First of all, making the cement is bad because limestone, which is in the cement, is turned into lime by baking at it at these really high temperatures. And what that

does actually is it releases a lot of carbon dioxide, which is a very potent greenhouse gas into the

...