Calculations finally match ß-decay rates

Effective field theory combines with measurements of light- to medium-mass nuclei to resolve a 50-year-old puzzle.

When measuring ß decay in medium and heavy nuclei, physicists have had to adjust, or quench, the calculated rate to match the observed rate by a factor of 0.75. Peter Gysbers (TRIUMF, Canada’s particle accelerator center), Gaute Hagen (Oak Ridge National Laboratory), and their colleagues have now developed an explanation for the mismatch between theory and observation that has puzzled nuclear physicists for the past half century. The researchers combined effective field theory and quantum many-body methods to calculate ß-decay rates in different-sized nuclei. Comparing those calculations with measured rates led the researchers to conclude that the discrepancy arises from powerful particle interactions in the nucleus. Read more.

Scientists Dropped Dead Gators to the Seafloor to See What Bites

It takes a lot to go from the bayou to the deep sea.

Craig McClain knows all about falls. He’s seen whale falls, shark falls, manta ray falls, even, on one occasion, a sea lion fall. In the nutritional wasteland of the deep sea, a fall—any big hunk of organic material that manages to sink—creates a temporary feast for nearby scavengers. In his work as executive director of the Louisiana Universities Marine Consortium, McClain regularly creates wood falls, by deliberately dropping deciduous chunks to the bottom of the seafloor, just to see what bites and learn more about deep sea ecosystems. So it was almost surprising that it took McClain years of working in a Louisiana lab to consider one, rather obvious, question: What about a gator fall? Read more.

How Did We Get Here?

With a discovery made from fossils in the seabed, paleoceanographers and paleoclimatologists began tracing the delicate path between ancient eras and our future.

The shells of tiny ancient sea organisms hold the evidence that underpins one of the newest fields in the Earth sciences. In the 1950s, Cesare Emiliani at the University of Chicago was learning how to measure stable isotopes in invertebrates and use those data as a proxy to make conclusions about environmental factors. One day he turned that study to ancient foraminifera taken from sediments in the ocean floor. The oxygen isotopes he found in their shells told him that the ocean was once much warmer—that, in fact, the ocean changed over time. Paleoceanography was born. Read more.

What Makes Tennessee Whiskey Unique?

When it comes to Tennessee whiskey, it’s all about the Lincoln County Process, aka LCP. Basically, wood from sugar maple trees is chopped, stacked in piles, and burned to create charcoal. Freshly distilled whiskey is then filtered through the charcoal, imparting the mysterious flavor that makes Tennessee whiskey, well, Tennessee whiskey.

But what’s really going on here? Read more.

Research: How fecal bacteria spread in streams —

Faecal bacteria — bacteria that are present in the digestive system of humans and animals — are known to contaminate waters. They can sometimes be a health hazard. Little research has been conducted into the spread and distribution of faecal bacteria in rivers and, above all, into their input from the surrounding landscape. Researchers have developed an indicator-based model that can be used to assess the dynamics of faecal bacteria such as E. coli on the basis of hydrological processes in the landscape and the connectivity of streams — an important basis for managing the acute or sustained microbial contamination of waters. Read more.