1. University of Trieste, Department of Physics, Trieste
2. University of Cagliari, Department of Physics, Cagliari
3. University of Trieste, Department of Medical Science, Cattinara Hospital, Trieste
4. University of Ferrara, Department of Physics and Earth Science, Ferrara
5. University of Siena, Department of Physical Sciences, Earth and Environment, Siena
6. University of Napoli Federico II, Department of Physics, Napoli
7. INFN Division of Cagliari, Cagliari