1. a Faculty of Natural and Exact Science, Save University (UniSave), Chongoene, Mozambique
2. b Department of Physics, Faculty of Science, Eduardo Mondlane University (UEM), Maputo, Mozambique
3. c Centre for Marine Research and Technology (CePTMar), Eduardo Mondlane University, P.O. Box 128, Quelimane, Mozambique
4. d Department of Physics, Faculty of Science, Ibn Tofail University, B.P. 133, Kenitra, Morocco