For mice, carbon dioxide often means danger — too many animals breathing in too small a space or a hungry predator exhaling nearby. Mice have a way of detecting carbon dioxide, and new research from Rockefeller University shows that a special set of olfactory neurons is involved, a finding that may have implications for how predicted increases in atmospheric carbon dioxide may affect animal behavior.

Most olfactory sensory neurons express odorant receptor molecules that detect odors and reside within the lining of the nasal cavity. But a small subset express an enzyme called guanylyl cyclase-D (GC-D). Peter Mombaerts, professor and head of the Laboratory of Developmental Biology and Neurogenetics at Rockefeller, and Andreas Walz, a research associate in Mombaerts’s CO2 detector.

Astronomers have discovered a chaotic scene unlike any witnessed before in a cosmic “train wreck” between giant galaxy clusters. NASA’s Chandra X-ray Observatory and optical telescopes revealed a dark matter core that was mostly devoid of galaxies, which may pose problems for current theories of dark matter behavior.

"These results challenge our understanding of the way clusters merge," said Dr. Andisheh Mahdavi of the University of Victoria, British Columbia.

Scientists have determined for the first time the atomic structure of an ancient protein, revealing in unprecedented detail how genes evolved their functions.

"Never before have we seen so clearly, so far back in time," said project leader Joe Thornton, an evolutionary biologist at the University of Oregon. "We were able to see the precise mechanisms by which evolution molded a tiny molecular machine at the atomic level, and to reconstruct the order of events by which history unfolded."

A detailed understanding of how proteins – the workhorses of every cell – have evolved has long eluded evolutionary biologists, in large part because ancient proteins have not been available for direct study.

Wastewater treatment plants are designed primarily to eliminate nutrients. However, attention is increasingly being focused on micropollutants, since even low concentrations of these substances can have adverse impacts on aquatic ecosystems. Ozonation of wastewater appears to be a promising option for removing micropollutants at treatment plants.

Ozone, which consists of three oxygen atoms, is a reactive gas. It is a powerful oxidizing agent and forms hydroxyl radicals in contact with water. While ozone itself only oxidizes certain substances, the hydroxyl radicals attack a wide range of substances. Ozonation thus leads to the breakdown of various complex compounds, making substances much more susceptible to subsequent biological degradation.

Pressures and temperatures at the Earth’s core are stupendous – more than 3.5 Mbar and 7000K – and currently it is impossible to recreate these conditions in the laboratory. Our information about the core comes from observing the way that seismic waves travel through the core, extrapolating from experimental studies and studying iron rich meteorites.

As a result we know that the core is mostly iron, but that it also must contain some light impurities such as oxygen, silicon, sulphur, hydrogen and magnesium (because the density of the core is too low to be pure iron). The most significant impurity is thought to be nickel, which makes up between 5 and 15% of the composition.

Most studies on the Earth’s core have approximated the composition to be pure iron.

Prof. Yadin Dudai, Head of the Weizmann Institute’s Neurobiology Department, and his colleagues recently discovered that the process of storing long-term memories is much more dynamic than previously thought, involving a miniature molecular machine that must run constantly to keep memories going. They also found that jamming the machine briefly can erase long-term memories. Their findings may pave the way to future treatments for memory problems.

Dudai and research student Reut Shema, together with Todd Sacktor of the SUNY Downstate Medical Center, trained rats to avoid certain tastes. They then injected a drug to block a specific protein into the taste cortex – an area of the brain associated with taste memory.