A new method for carbon isotopic analysis of protein

The reaction of ninhydrin with amino acids can be used in carbon isotopic studies of protein. The reaction can be applied to extract as carbon dioxide only peptide-bonded carbon in proteinaceous material, thus avoiding most, if not all, contaminants. Test radiocarbon dates on ancient bone indicate that the method provides reliable ages, and stable carbon isotopic data suggest that our understanding of isotopic dietary reconstruction needs detailed examination. The technique should also be useful in biochemical tracing experiments and in global carbon budget studies, and the underlying principle may be applicable to other isotopes and molecules.     

New horizons mapping of Europa and Ganymede

The New Horizons spacecraft observed Jupiter's icy satellites Europa and Ganymede during its flyby in February and March 2007 at visible and infrared wavelengths. Infrared spectral images map H2O ice absorption and hydrated contaminants, bolstering the case for an exogenous source of Europa's "non-ice" surface material and filling large gaps in compositional maps of Ganymede's Jupiter-facing hemisphere. Visual wavelength images of Europa extend knowledge of its global pattern of arcuate troughs and show that its surface scatters light more isotropically than other icy satellites.     

Categorical perception of a natural stimulus continuum: birdsong

A fundamental issue in perception and communication is how continuously varying stimuli are partitioned into discrete categories. In swamp sparrow songs, note duration is a critical feature distinguishing two note categories with different roles in song construction. Pairs of songs with initial notes from different categories contrast more in their effects on territorial males than song pairs with initial notes differing by the same amount but taken from within one note category. The results indicate categorical perception by wild swamp sparrows.