About Shelley Schlender
We talk with one of the nation’s leading nutrition scientists . . . whose opinions about food and health might not be popular with the American Salt Institute . . . OR with the USDA. Dariush Mozaffarian is with the Harvard School of Public Health, in the department of epidemiology. Current projects include leadership of the Nutrition in Chronic Diseases Expert Group of the Gates Foundation. He’ll explain data that indicates processed lean turkey meat and processed lean ham are a greater risk factor for diabetes and heart disease than eating an equal size serving of fresh, fat, juicy steak. Mozaffarian talks with Shelley Schlender. (and for an extended version of the interview, click here)
And we talk with CU astronomer Jason Glenn. He’s one of the principal investigators on the Z-Spec telescope, operated out of Hawaii. Recently, Glenn’s team has discovered an enormous cloud of water hanging in space—12 billion light-years away. Astronomers have never before found water from that far back into the early universe. Glenn talks about the finding with Ted Burnham.
Also in this week’s show, we talk with Janos Perczel about a new design for an invisibility cloak. (and for an extended version of the interview, click here)
Co-hosts: Joel Parker and Ted Burnham
Engineer: Shelley Schlender
Executive Producer: Susan Moran
Producer: Shelley Schlender
An undergraduate at the University of St. Andrews in Scotland has overcome a major hurdle in the development of invisibility cloaks by envisioning an optical device that would allow the cloak to hide things against CHANGING backgrounds. The Institute of Physics and German Physical Society’s New Journal of Physics, published the study today, and the lead author, Janos Perczel, spoke with us about it from Hungary, via Skype,. But first — putting aside Harry Potter’s cloak of invisibility for a moment, in real life, scientists have cloaked some palm-sized objects . . . but not especially well. Here’s Janos Perczel.
It depends on what you mean by an invisibility cloak. The sort of stuff you see in Harry Potter films has never been made yet. There have been experiments to test the theory but these experiments have always featured invisibility in some reduced form.
So far, cloaking only works when an object’s against one single field of steady background wavelength, like a “blue screen.” And even that’s complicated. “Cloaking” conceals an object by bending light around it. Perczel says it’s similar to putting a rock in a river, where the water bends around and covers the rock and makes it “disappear.. But just as water must speed up in order to hurry around the rock, bending light has required accelerating the light. And super-speeded light flows too fast to allow a cloaking devices to adjust to changing backgrounds. In the new report, Perczel and colleagues offer a solution. They call it an invisibility sphere, and it buys enough time for the cloak to adjust to changing backgrounds by, well — what else? Their device slows down the normal speed of light.
So that all the light speeds that we use in our cloak will be less than the speed of light, in vacuum, so that the cloak we propose here would work for any frequency and would also work against an ever-changing background and a multiplicity of colors and, well anything.
It may be decades before this technology moves from theory to real world applications. But Perczel predicts that there will be plenty.
I’m not sure I would want to talk about the potential military applications, because that’s not something I’m terribly keen on. But, apart from those, this whole invisibility subject is based on transformation optics. That’s the key word here, and it tells us how to control light and how to guide it pretty much any way we want to guide it around. This might lead to the birth of incredible optical devices.
Perczel envisions images that are sharper than the quality of the light the first hit the lens. And who knows? Maybe someday invisibilites cloaks will lead to anti-wrinkle creams and perhaps lower production costs of future Harry Potter movies. Thanks to Shelley Schlender for doing this report. You can hear an extended version of the interview, on our website, howonearthradio.org.
Here’s an extended version of Shelley Schlender’s interview with Dariush Mozaffarian on Salt. Note that in the interview, Shelley asks Dr. Mozaffarian to comment on some of the assertions made in the popular press, Scientific American story, It’s Time to End the War on Salt.” The interview mentions a citation in the popular press article about the Cochrane Collaboration’s view on salt. After the interview, Mozaffarian’s pointed out this more recent assessment from the Cochrane Collaboration:
The most recent on salt and blood pressure is below:
Cochrane Database Syst Rev. 2004;(3):CD004937.
Effect of longer-term modest salt reduction on blood pressure.
He FJ, MacGregor GA.
Here are the verbatim conclusions from that report:
“CONCLUSIONS: Our meta-analysis demonstrates that a modest reduction in salt intake for a duration of 4 or more weeks has a significant and, from a population viewpoint, important effect on blood pressure in both individuals with normal and elevated blood pressure. These results support other evidence suggesting that a modest and long-term reduction in population salt intake could reduce strokes, heart attacks, and heart failure. Furthermore, our meta-analysis demonstrates a correlation between the magnitude of salt reduction and the magnitude of blood pressure reduction. Within the daily intake range of 3 to 12 g/day, the lower the salt intake achieved, the lower the blood pressure.”
Additionally, Mozaffarian suggests that people interested in this topic check out a meta-analysis by the British Journal of Medicine Titled, Salt intake, stroke, and cardiovascular disease: meta- analysis of prospective studies.
Last but not least, for a recent speech by Mozaffarian that provides even more detail on these topics, click here.
Two million years ago, two-legged apes roamed the African landscape. Many of these ancient hominins, lived in limestone caves in what is now South Africa. We know this through fossilized skull fragments and teeth from those caves.
But fossils only tell us where an individual died—not where it grew up, or where it traveled during its life. Or do they? New research from the University of Colorado that’s been published in the journal Nature, reveals that male hominins in South Africa grew up in the caves where they died, while the females who died there grew up elsewhere and migrated to the caves as adults.
The research not only sheds light on the behaviors of early human relatives; it makes use of a new technique, pioneered by the CU researchers, to quickly and cheaply analyze the birthplace of fossilized creatures.
For Headline Features, read on . . .
FRIDAY – PART 1: Health and Medical Problems Everywhere
Moderator: Fintan Steele, CIMB at CU, Boulder
9 AM: “Our Dialogue, One Year Later”