Concerns about money laundering and financing of terrorist networks mean new payment providers not only have to deal with the usual red tape but also cope with layers of additional regulation.

ECONOMIST: Online payments

But in fact, young red leaves are equally common throughout a forest's layers.

ECONOMIST: Young leaves, as well as old ones, are often coloured red

By carefully tailoring the semiconductor layers, the researchers can make lasers that shine in two bands of infra-red light to which the atmosphere is highly transparent allowing the light to travel a long way.

ECONOMIST: Lasers