Acknowledgements

Financial funding for this work was supplied by the Dirección General de Asuntos del Personal Académico (DGAPA) from the Universidad Nacional Autónoma de México (UNAM), grants PAPIIT IN106215 and IV100116 and in particular grant IA105017 in the context of which the Fourier filter was discussed into detail with Wady A. Rios-Herrera, Francisco F. de Miguel, Martha Yoko Takane Imay, David Serrano, Octavio B. Lecona and Silvia Diaz Gómez. We also gratefully acknowledge grants 2015-02-1093, 2016-01-2277 and CB-2011-01-167441 from the Consejo Nacional de Ciencia y Tecnologia (CONACyT). We are thankful for the Newton Advanced Fellowship awarded to RF by the Academy of Medical Sciences through the UK Governments Newton Fund programme. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. Authors do not have any conflict of interest.
