1. Centre for Technological Applications and Nuclear Development (CEADEN); CP. 6122 Playa Havana Cuba
2. Department of Nuclear Energy (UFPE/DEN); Federal University of Pernambuco; 1000 Cidade Universitaria Recife Brazil
3. Institute of Ecology and Systematic (IES); Boyeros Havana Cuba
4. On leave to International Atomic Energy Agency (IAEA); A-1400 Vienna Austria