The very oldest Koranic fragments owned by the Leiden University Libraries date back to the second half of the seventh century, between 30 and 70 years after the death of the Prophet Muhammad. This has been shown by newly conducted radiocarbon analyses. This finding agrees with official Islamic teachings.
Frogs evaluate different streams of information to assess how they should react to rivals. This is what Leiden biologist Wouter Halfwerk has discovered. He has published an article about it in the journal Current Biology
Risk-taking and sensation-seeking are typical behaviour for adolescents. Research by Leiden psychologist Barbara Braams and her colleagues published in NeuroImage shows that the social context also plays an important role.