From February, all new and renovated flat roofs in Antwerp have to be "green roofs", on which plants grow to assist insulation, the city council has voted. Green roofs protect against the sun and hold heat inside the house. They also retain rainwater and put less pressure on sewer systems. Subsidies will be available for the installation of green roofs, the city said. Meanwhile, across Flanders, property owners who have not insulated their roofs by 2020 will not be allowed to rent their property out, housing minister Freya Van den Bossche has announced.

The new saliva test used by police to detect motorists under the influence of amphetamines and cannabis also reacts positively to the prescription drug Ritalin, used to treat cases of attention deficit hyperactivity disorder (ADHD). Such cases will not attract a fine, the mobility ministry said, but drivers may have their licence withdrawn for 12 hours before a second test is carried out. The new saliva tests have been criticised by scientists for too many false positive results.

The Université Catholique de Louvain-la-Neuve (UCL), which split from the Catholic University of Leuven (KUL) in 1968, has been returned to Flanders by the prestigious British scientific journal Nature. In its last issue, the journal assigned 61.7% of the nation's researchers to Flanders because it had assumed that UCL was in Leuven. Instead of 21% of researchers working in Wallonia, the figure is closer to 33%.

Meanwhile in Leuven, the KUL is one of only seven universities in Europe to achieve excellence in all seven subject areas surveyed by the German think tank Centre for Higher Education Development. The others universities, in Amsterdam, Bristol, London, Manchester, Munich and Oxford, all scored highly in study and research opportunities in biology, chemistry, physics, mathematics, economics, psychology and political science. www.che.de

Belgium has dropped one place in the world transparency rankings, issued annually by Transparency International. Belgium is now considered the 22nd most transparent (or least corrupt) country in the world, tied with the United States, which fell out of the Top 20 for the first time. Denmark, New Zealand and Singapore top the least-corrupt list with 9.3 points out of 10, while Belgium scores 7.1. The most corrupt country in 2010 is Somalia with 1.1 points. www.transparency.org

Flemish public broadcaster VRT will collaborate with dictionary publisher Van Dale to find the Word of the Year for 2010. This year, for the first time, separate polls will be held in the Netherlands and Flanders. The categories are lifestyle, sport and leisure, economy, politics and the language of youth. Previous winners include ontvrienden (to "unfriend" someone on Facebook). Nominations are invited on the website. http://woordvanhetjaar.vandale.nl