Rapid growth of urban ultrafine aerosols and their impact on shallow clouds and precipitation in the Amazon rainforest Zaveri, R. A.; Wang, J.; Fan, J.; Zang, Y.; Shilling, J.; Zelenyuk, A.; Mei, F.; Newsom, R. K.; Pekour, M. S.; Tomlinson, J. M.; Comstock, J. M.; Shrivastava, M.; Fortner, E.; Machado, L. A. T.; Artaxo, P.; Martin, S. T. Conference Paper