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In this paper we describe briefly some characteristics of the Accelerator Mass Spectrometry (AMS) technique and the need of corrections in the radiocarbon ages by specific calibration curves. Then we discuss previous results of some Brazilian projects where radiocarbon AMS had been applied in order to reevaluate the dates obtained on the basis of the new calibration curves available.

The accumulation and distribution of 40K and 137Cs in tropical plant species were studied through measurements of gamma-ray spectra from mango, avocado, guava, pomegranate, chili pepper, papaya and manioc trees. Our goal was to infer their differences in the uptake and translocation of ions to the aboveground plant parts and to establish the suitability of using radiocaesium as a tracer for the plant uptake of nutrients such as K+.

We have used a parameter - free potential, obtained from data analysis at sub-barrier energies, to explain our measurements of elastic and several inelastic scattering cross sections for the 16,18O + 58Ni systems at an energy above the barrier. The data were analyzed through extensive coupled-channel calculations. Transfer cross sections could also be explained by the same interaction, which is consistent with the more fundamental São Paulo potential.

We give an overall picture of our present understanding of the effect of the break-up of stable weakly bound nuclei on their fusion cross section with light, medium and heavy mass nuclei, at energies above the Coulomb barrier. The discussion is based mostly on recent data obtained by our group in collaborative experiments with ANU, USP and Tandar Laboratories. We conclude that there is complete fusion suppression for heavy targets, due to the loss of flux, corresponding to the occurrence of incomplete fusion of one of the break-up fragments. For medium and light mass targets, the incomplete fusion is negligible and therefore is no complete fusion suppression.

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