This spring, a Swedish scientist sparked international concern with a journal article saying that radioactive particles detected in 2010 showed North Korea had set off at least two small nuclear blasts — possibly in experiments designed to boost yields of much larger bombs. Separate claims surfaced that intelligence agencies suspected the detonations were done in cooperation with Iran. Now, a new paper says the tests likely never took place — or that if they did, they were too tiny to have any military significance.

Researchers have developed a new software system capable of estimating greenhouse gas emissions across entire urban landscapes, all the way down to roads and individual buildings. Until now, scientists quantified carbon dioxide emissions at a much broader level. “Hestia” combines extensive public database “data-mining” with traffic simulation and building-by-building energy-consumption modeling.

An international team of scientists has found that a clear difference exists between the marine microbial communities in the Southern and Arctic oceans. Their report contributes to a better understanding of the biodiverisity of marine life at the poles and its biogeography.