Outline of the progress in the study of radioactive nuclear physics and super-heavy nuclei

We briefly introduce the current status and progress in the field of radioactive ion beam physics and the study of super-heavy nuclei. Some important problems and research directions are outlined, such as the sub-barrier fusion reaction, the direct reaction at Fermi energy and high energies, the property of nuclei at drip-lines, new magic numbers and new collective motion modes for unstable nuclei and the synthesis and study of the super-heavy nuclei.

Enhanced biological effect induced by a radioactive C-9-ion beam at the depths around its Bragg peak

To explore the potential of double irradiation source, radioactive C-9-ion beam, in tumor therapy, a comparative study oil the surviving effect of human salivary gland cells at different penetration depths between C-9 and C-12-ion beams has been carried out. The 9C-ion C beam, especially at the distal side of the beam came out more efficient in cell killing at the depths around its Bragg peak than the 12 Bragg peak. Compared to the C-12 beam, an increase in RBE by a factor of up to 2.13 has been observed at the depths distal to the Bragg peak of the 9C beam. The 9C beam showed an enhanced biological effect at the penetration depths around its Bragg peak, corresponding to the stopping region of the incident C-9-ions and where the delayed low-energy particles were emitted. Further analysis revealed that cell lethality by the emitted particles from the stopping C-9-ions is responsible for the excessive biological effect at the penetration depths around the Bragg peak of the C-9 beam.

timng of the last glacial maximum from observed sea level minima

During the Last Glacial Maximum, ice sheets covered large areas in northern latitudes, and global temperatures were significantly lower than today. But few direct estimates exist of the volume of the ice sheets, or the timing and rates of change during their advance and retreat. Here we analyze four distinct sediment facies in the shallow, tectonically stable Bonaparte Gulf, Australia - each of which is characteristic of a distinct range in sea level - to estimate the maximum volume of land-based ice during the last glaciation and the timing of the initial melting phase. We use faunal assemblages and preservation status of the sediments to distinguish open marine, shallow marine, marginal marine and brackish conditions, and estimate the timing and the mass of the ice sheets using radiocarbon dating and glacio-hydroisostatic modelling. Our results indicate that from at least 22,000 to 19,000 (calendar) years before present, land-based ice volume was at its maximum, exceeding today's grounded ice sheets by 52.5 x 10 exp 6 cu km. A rapid decrease in ice volume by about 10 percent within a few hundred years terminated the Last Glacial Maximum at 19,000 +/- 250 years.