Free Republic

A newly examined ice core shows what may be the chemical traces of supernovae that exploded a thousand years ago. Yuko Motizuki of the RIKEN research institute in Wako, Japan, and colleagues analysed the nitrate content of an ice core drilled at Dome Fuji station in Antarctica. Nitrate is produced in the atmosphere by nitrogen oxides, which in turn should be created by the gamma radiation from a supernova. Motizuki's group found high nitrate concentrations in three thin layers about 50 metres deep. Because snow gradually builds up into layers of ice, depth indicates age. After calibrating this icy calendar...

The Japanese laboratory that retracted a paper reporting a potentially major breakthrough in stem cell research said Wednesday its researchers have not managed to replicate the results. Scientists at the government-affiliated Riken Center for Developmental Biology said they are still trying to match results reported in two papers published by the journal Nature in January and then retracted in July. […] (Riken scientist Haruko) Obokata and other researchers in Boston and Japan participating in the project said they used a simple procedure to turn ordinary cells from mice into stem cells. They exposed cells from spleens of newborn mice to...