Dozens of academic papers containing apparently plagiarized work have been removed by moderators from arXiv, the popular preprint server where many physicists post their work before publication, Nature (subscription required) is reporting. According to the article, 67 papers by 15 physicists at four Turkish universities were pulled after an examination of their content revealed that they “plagiarize the works of others or contain inappropriate levels of overlap with earlier articles.”

Nature quotes Mustafa Salti, a graduate student at the Middle East Technical University whose name was on 40 of the problematic papers, defending his work: “Most of our papers have been published in the science citation index journals. Until now no one has claimed that we plagiarize.”

Suspicions were apparently stoked when, during oral defenses of their dissertations last fall, Mr. Salti and another student demonstrated a poor grasp of even the most basic of physics concepts. Professors at the university began to investigate the students’ work and turned up several examples of plagiarized work by them, as well as by students and professors at three other Turkish universities — Dicle University, the University of Mersin, and Çanakkale Onsekiz Mart University.

The investigating professors notified the moderators of the arXiv site, which is based at Cornell University. The service’s founder, Paul Ginsparg, told Nature that the incident was the worst case of plagiarism the site had ever experienced. —Aisha Labi