Physicists at the National Institute of Standards and Technology (NIST) have demonstrated a novel way of making atoms interfere with each other, recreating a famous experiment originally done with light while also making the atoms do things that light just won't do.

Their experiments showcase some of the extraordinary behavior taken for granted in the quantum world—atoms acting like waves and appearing in two places at once, for starters—and demonstrate a new technique that could be useful in quantum computing with neutral atoms and further studies of atomic hijinks.

Childhood obesity is widely recognised as a major contributor towards cardiovascular diseases, diabetes, sleep disorders, and psychological and social problems. The China National Nutrition and Health survey in 2002 revealed that the prevalence of overweight individuals has increased overall by 39% in the past ten years.

In Xi'an City, where the new study was conducted, 20% of the adolescents were found to be overweight, a rate similar to that observed in many western countries. In a recent report in the European Journal of Clinical Nutrition, researchers found the following factors were significantly associated with overweight and obesity in children included:

• living in urban districts

Researchers at NIST, in collaboration with scientists from the University of Maryland and Howard University, have developed a technique to create tiny, highly efficient light-emitting diodes (LEDs) from nanowires. As described in a recent paper,* the fabricated LEDs emit ultraviolet light—a key wavelength range required for many light-based nanotechnologies, including data storage—and the assembly technique is well-suited for scaling to commercial production.

Why are there no Unicorns?

Perhaps horses develop in a way that cannot be easily modified to produce a Unicorn, so such creatures have never arisen. Or maybe Unicorn-like animals have been born in the past but because there is no advantage for a horse to have a horn, such creatures did not thrive and were weeded out by natural selection.

In a fundamental discovery that someday may help cure type 1 diabetes by allowing people to grow their own insulin-producing cells for a damaged or defective pancreas, medical researchers here have reported that they have engineered adult stem cells derived from human umbilical cord blood to produce insulin.

Their paper cites six years of research and calls it "the first demonstration that human umbilical cord blood-derived stem cells can be engineered" to synthesize insulin.

On 12 May 2007 Cassini obtained this image showing the coastline and an archipelago in a portion of a large sea, consistent with the larger sea seen by the Cassini imaging instrument.

Like other liquid bodies seen on Titan, this feature reveals channels, islands, bays, and other features typical of terrestrial coastlines and the liquid, most likely a combination of methane and ethane, appears very dark in radar. What is striking about this portion of the sea compared to other liquid bodies on Titan is the relative absence of brighter regions within it, suggesting that the depth of the liquid here exceeds tens of metres.