"Following recent events, Bora Zivkovic has offered his resignation from Scientific American, and Scientific American has decided to accept that resignation," the statement said.
It made reference to a year-old incident in which Zivkovic was accused of and admitted to harassment, but which was not disclosed until this week. "When Monica Byrne contacted Scientific American a year ago, we investigated her report, offered the Company's apologies and Ms. Byrne acknowledged in her blog that she was satisfied with our response. We were unaware of any additional allegations until this week. Our investigation of those is continuing and we will investigate any additional allegations that are reported to us."
The most recent allegation of harassment came in a wrenching account this morning by Kathleen Raven at Medium. "I fear that if I don’t say something now, I won’t be able to, and neither will any other woman," she wrote.
You can find another account of the week's developments in a post by Tabitha M. Powledge at On Science Blogs.