The research follows a study by a team in Pittsburgh, USA, published earlier this year which found no evidence that the drug posed an increased risk of heart disease.
And when they replicated this studyin 15 countries in Europe, Obama had almost double more positive emotional impact on people outside the USA compared to Romney.
The study, published in the journal "Proceedings of the National Academy of Sciences of the USA, " suggests that the number of amphibian species in Madagascar has been significantly underestimated.