1. Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
2. Laboratory of Mycology, Department of Earth, Environment and Life Sciences, University of Genova, Corso Europa 26, 16132 Genoa, Italy
3. Department of Physics, University of Genova, INFN-Division of Genova, 16146 Genoa, Italy
4. National Institute of Nuclear Physics (INFN)-Division of Genova, 16146 Genoa, Italy