Footnotes

• Handling editor Anna Maria Geretti

• Twitter @ismaelmaatouk, @boudyassi, @ProfRJaspal

• Contributors IM drafted the paper; MA reviewed data and RJ reviewed the overall paper. The three authors approved this final version.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Provenance and peer review Not commissioned; externally peer reviewed.