In the midst of another action-packed week at the BA, Ismail Serageldin and Dr. Mohamed Hassan welcomed TWAS members from the Arab region to the launch of the Arab Regional Office of the Third World Academy of Sciences (TWAS-ARO) at the BA. The initial meetings discussed the objectives, strategy and work plan that the regional office would undertake. Headquartered at the BA, the TWAS-ARO aims to further promote the activities of TWAS and its affiliated organizations. Serageldin delivered the introductory address titled "Challenges and Opportunities". A welcome speech by Dr. Mohamed Hassan ensued. The closing session featured Professor Edward Witten in a presentation on Cosmic Acceleration.