News At Seven-Thirty highlights: mainland authorities say Ai Weiwei was detained for suspected economic crimes; Stephen Lam had heart surgery today; NATO came under criticism from rebel leaders in Libya; fighting continues to rage around the presidential palace in Ivory Coast; Spain’s finance minister said spain won't be next in line for a bailout; a construction worker was killed and 2 injured in an industrial accident on Tuen Mun Highway; 2 major publishing groups agreed to sell textbooks and teaching materials separately; Tony Chan reported back to the police in connection with suspected forgery of a will of Nina Wang; a cow in Germany was trainned as a horse.