Three MIT students can now talk, but not because of their right to free speech. For the past 10 days, the trio has been restrained by a judge's order from describing their now-celebrated exposure of a flaw in the Boston transit system fare card. Yesterday a U.S. District Court judge in Boston lifted the gag order because he did not believe the students had violated a federal law against transmitting malicious computer software, CNET reports. Many had expected the matter to be decided along First Amendment interpretations, but instead the decision turned on the issue of what counted as "transmission" of software and what did not. The three, as The Chronicle reported last week, showed there were vulnerabilities in the computer-read cards used to pay fares on the Boston subway, flaws that could allow people to get a free ride. The Electronic Frontier Foundation, which is providing a lawyer for the students, said the work was done to show the flaws in the system so they could be fixed before a malicious attacker used them. (The students' paper got an A in an MIT computer-science class.) But the Boston transit system sued to stop the students from talking about the research at Defcon, a hacker convention, citing the Computer Fraud and Abuse Act. Talking about the code publicly, the transit system argued, was an illegal transmission of a computer program under the act. A judge who was on duty the weekend the suit was filed issued a temporary restraining order that silenced the students until a hearing could be held. On Tuesday another judge, George O'Toole Jr., gave the students leave to speak. The talk they had planned to give at Defcon was not a computer-to-computer transmission but simply a talk to people, he said. He also noted that the transit system had not proved the students had caused at least $5,000 damage, a provision for invoking the federal statute. Ruling that the law was not applicable, Judge O-Toole avoided any First Amendment issues. That did not, however, stop the EFF from issuing a statement describing the decision as a "free speech victory." After today's ruling, the Boston transit system could continue pressing its lawsuit, but statements from officials indicated they were not too keen on that idea. And the students can reveal the details of their work in public. Whether they will or not is anyone's guess. Their lawyer wasn't saying. --Josh Fischman

Whenever you have to share digital files, think of the Internet: do it locally. Researchers at the University of Washington and Yale University have found that sharing files through peer-to-peer networking with neighbor computers instead of with far-away machines relieves pressure on the Internet-service provider by as much as five times and speeds up the transfer by 20 percent. Besides being widely used for murky purposes, P2P is used by several media outlets to deliver legal video content and movies. Around 50 percent to 80 percent of all Internet traffic is generated by bandwidth-greedy P2P exchanges, and it is expected to grow, putting strain on Internet-service providers. To solve this problem, the researchers propose a system they have dubbed P4P, which consists of sharing files preferentially with nearby computers. The researchers calculated that the average P2P data packet travels 1,000 miles and takes 5.5 connections through major hubs. The new system allows data to travel 160 miles on average and make only 0.89 connections, which reduces Web traffic on connections between cities, where there are more frequent bottlenecks. A working group consisting of 80 members, including representatives from Internet-service providers and content-supplying companies has been exploring P4P since last year. The research team is presenting a paper on their system this week at the Association for Computing Machinery's Special Interest Group on Data Communications meeting in Seattle. --Maria José Viñas

PubMed Central, the National Library of Medicine's online database, is now indexing videos from The Journal of Visualized Experiments. According to the publication's official blog, JoVE is "the first video-journal to ever be accepted for publication in PubMed." The online, open-access journal publishes videos of experiments and protocols in the biological and life sciences and offers its video-articles to science bloggers to illustrate their posts. The journal managers say that PubMed's decision is an "official acceptance" of the scientific community of new forms of communication. "Overall, it will increase the interest of the scientists to communicate their findings in video, making biological sciences more transparent and efficient," Moshe Pritsker, the co-founder of JoVE, told Wired. --Maria José Viñas

Large classrooms with frequent absences: Those are the environments where students seem most likely to benefit from computer-assisted instruction, according to a working paper released last week by the National Bureau of Economic Research. The paper reports on an experiment in three urban school districts in the United States. In the study, 152 pre-algebra and algebra classes were randomly assigned to use either traditional “chalk-and-talk” instruction or a commonly used computer package known as I Can Learn. The students in the computer-aided classes had significantly better (0.17 of a standard deviation) scores on end-of-semester tests than did the students in traditional classes. Those positive effects were strongest in classes with high levels of absenteeism, in classes where students had relatively heterogeneous levels of math skills, and in large classes. (Among classes with 15 or fewer students, computer-assisted and traditional instruction proved equally effective.) Insofar as computer-assisted instruction is valuable, the scholars suggest, it is because it allows more individually tailored instruction in large, diverse classrooms where teachers find it hard to target each student with the appropriate level of work. The authors caution against drawing too many conclusions from this single experiment, but they also propose that computer-assisted instruction might be more feasible for many districts than trimming their classes to 15 or fewer students. “In urban and rural districts that have difficulty hiring highly qualified mathematics teachers,” they write, computer-assisted instruction "may be much easier to implement than a reduction in class size.” The paper – whose authors are Lisa Barrow, an economist at the Federal Reserve Bank of Chicago; Lisa B. Markman, associate director of Princeton University’s Education Research Section; and Cecilia E. Rouse, a professor of economics and public affairs at Princeton – is available for $5 from the bureau. An earlier version is available at no charge from the Social Science Research Network. --David Glenn

Four projects from researchers at more than a dozen universities and other research institutions have been awarded $10-million grants in the first edition of a competition that aims to expand the frontiers of computing. The initiative, Expeditions in Computing, has been promoted by the Directorate for Computer and Information Science and Engineering at the National Science Foundation. The winning team from Princeton University, Rutgers University, New York University, and the Institute for Advanced Study aims to solve longstanding problems of computing. A joint project of Cornell University, Bowdoin College, the Conservation Fund, Howard University, Oregon State University, and the Pacific Northwest National Laboratory, which brings together computer scientists, mathematicians, economists, biologists, and environmental scientists, wants to develop a new field of computational sustainability. An initiative based at Stanford University plans to address issues emerging in the broadband, wireless mobile era, while a team from the California Institute of Technology and the University of Washington will develop computer-science principles for programming information-bearing molecules, such as DNA and RNA polymers.More details about the winning projects are available in a press release. --Maria José Viñas