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Video: A Lone Gunman? Using Statistics in Forensics

Robert Frederick

There were five bullet fragments groups in President Kennedy’s assassination, but if those fragments came from more than two bullets, it would have been very difficult to conclude that Lee Harvey Oswald was the only shooter.

In 1978, however, radiochemist Vincent P. Guinn testified before Congress that the composition of each of the five bullet fragments showed that they came from two—and only two—bullets. “There is no evidence for three bullets, four bullets, or anything more than two, but there is clear evidence for two,” Guinn said (8 September 1978 hearings before the Committee on Assassinations).

The problem with Guinn’s conclusion, however, is that he relied only on chemical analysis.

“Bias is a big problem in forensic science,” says Clifford Spiegelman of Texas A&M University, because forensic scientists are often tasked to look for verification of what police officers or federal investigators already suspect.

See the associated blog for more.

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Video: Cyber-Enabled Bionic Organisms

Robert Frederick

The future of search-and-rescue missions may be in the form of insect-sized robots. Researchers are creating such robots because of insects’ unmatched ability to navigate through a wide variety of environments, including the rubble of collapsed buildings. So far, though, the technology suffers from mechanical challenges. Tiny robots have a hard time carrying a sufficient power supply, for example, or bending their “legs” thousands of times without breaking the material they’re made from.

So, by merging current technologies with biological organisms, Alpert Bozkurt of North Carolina State University has found a way to control insects directly. His team successfully interfaced bionic systems with cockroaches.

See the associated blog for more.

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Video: How Hair Ice Forms

Fenella Saunders

In 2013, American Scientist featured an article on odd ice formations on plant stems.

One of the types of ice discussed in the article was hair ice—long, thin strands of ice that grow under quite specific conditions. The only problem is that a new study shows the theory put forth at the time—that gas pressure pushes the water out—isn’t correct.

We asked Christian Mätzler, a physicist at the University of Bern in Switzerland, and the lead author of the study, to provide an update on the hair ice formation mechanism.

See the associated blog for a full transcript of the video.

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Slideshow: Where the Xingu Bends and Will Soon Break

Katie L. Burke, Barbara Aulicino

Mark Sabaj Pérez is an ichthyologist whose expertise includes photographing fish up close and in detail. In this slideshow, we wanted to showcase some of the stunning visuals from his recent feature, "Where the Xingu Bends and Will Soon Break," which serves as a biologist's ode to Brazil's Xingu River, where the controversial Belo Monte megadam is slated to go into operation soon, changing its extensive rapids and diverse habitats. The author has been working with a team of Brazilian and American scientists on the iXingu Project to document the biodiversity of the river before the dam is in operation.

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Audio Exclusive: Discussing Rare Desert Species with Author Christopher Norment

Dianne Timblin, Katie-Leigh Corder

2015-11NormentCoverClick to Enlarge ImageFor our very first Scientists' Nightstand podcast, author Christopher Norment joins us to discuss his book, Relicts of a Beautiful Sea: Survival, Extinction, and Conservation in a Desert World, from University of North Carolina Press. It tells the story of six rare desert species native to the Death Valley region. Along the way Norment considers practical and ethical questions about conservation, especially around the issues of water use and climate change. He offers an eloquent and personal take on evolutionary history, firmly grounded in ecological science, enlivened by closely observed detail. Relicts of a Beautiful Sea presents a convincing argument for biodiversity conservation.

Christopher Norment is professor and chair of the Department of Environmental Science and Biology at the State University of New York College of Brockport. He's the author of several books including In the Memory of the Map: A Cartographic Memoir from the University of Iowa Press. He spoke to us in Durham, North Carolina, while he was here to present a lecture and reading for the E. O. Wilson Biodiversity Days, an event presented by the E. O. Wilson Biodiversity foundation and Duke University's Nicholas School of the Environment.

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Audio Exclusive: An Interview with Fracking Expert Avner Vengosh

Katie L. Burke

Avner Vengosh is a geochemist at Duke University who studies water quality issues posed by hydraulic fracturing and shale gas extraction. “We try to provide an objective picture of what the issues are and how we can cope with them,” says Vengosh. Listen to Associate Editor Katie L. Burke’s interview with Vengosh, portions of which were published as a Q & A in our July–August issue.

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3D Printing Replacement Body Parts

Katie-Leigh Corder, Fenella Saunders

2015-08WyskMMClick to Enlarge ImageResearchers in the regenerative medicine field are now amplifying their efforts with 3D-printing technology, which can now use organic materials to create scaffolds that cells need to grow into their final forms.

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The Living World in Eight Mandalas

Katie-Leigh Corder, Sandra J. Ackerman, Barbara Aulicino

2015-09ArtsLabBabaianF3.pngClick to Enlarge ImageCaryn Babaian, an artist and a biology instructor, has found a visual format that encourages her students to see and think about the important interactions in biology. Here she explains why the mandala, a Buddhist or Hindu graphic symbol of the universe, lends itself so well to the teaching of biology.

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Video: A Lone Gunman? Using Statistics in Forensics

Forensic scientists are often tasked to look for verification of what police officers already suspect, making bias a big problem.... (click the link above to read more).

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