Biofuels contribute to the mitigation of climate change. Directive 2003/30/EC thus aims at increasing the share of biofuels in total EU fuel consumption by up to 5.75 % by 2010. The rationale behind this directive can be found in potentially positive environmental impacts, most notably the...

The German practice of compelling weak students to repeat a class has come under heavy criticism recently. Many observers fear that this practice is, at best, useless or even counterproductive. However, little is known so far on the consequences of having to repeat a class, as compared to be...