Science: Patent trolls are companies that buy up the rights to a variety of patents and then pursue lawsuits against other companies over potential infringements of the patents. A bill introduced in the US House of Representatives in February is intended to make it more difficult for such companies to profit. Many companies in the electronics and high-tech industries support the bill. Universities, however, are grouping together to oppose it out of fear that it may hinder their ability to defend their own patent rights. American universities often gain patents based on the work of the professors and researchers they employ. Instead of then producing those inventions, the universities license the patent rights and often file lawsuits over infringements. Several university groups and a technology industry group have exchanged public letters calling for changes in stances or alternatives to the bill under discussion. However, the bill appears to have strong support in both the House and Senate.