denounced their parents. Many died through their ill-treatment or committed suicide. In 1968, youths were mobilized to go to the countryside in the Down to the Countryside Movement so they may learn from the peasantry, and the departure of millions from the cities helped end the most violent phase of the Cultural Revolution. Academics and education Academics and intellectuals were regarded as the "Stinking Old Ninth" and were widely persecuted. Many were sent to rural labor camps such as the May Seventh Cadre School. According to the official documents in the prosecution of the Gang of Four, 142,000 cadres and teachers in the education circles were persecuted. Noted academics, scientists, and educators who died included Xiong Qinglai, Jian Bozan, Wu Han, Rao Yutai, Wu Dingliang, Yao Tongbin and Zhao Jiuzhang. As of 1968, among the 171 senior members who worked at the headquarters of Chinese Academy of Sciences in Beijing, 131 were persecuted. Among all the members of the academy in China, 229 were persecuted to death. As of September 1971, more than 4,000 staff members of China's nuclear center in Qinghai were persecuted. More than 310 of them were permanently disabled, over 40 people committed suicide, and 5 were executed. During the Cultural Revolution, Chinese scientists still managed to successfully test the first missile, create the first hydrogen bomb and launch the first satellite in the Two Bombs, One Satellite program. There were also very significant achievements in both science and technology. These achievements laid the ground for further development in the post-Mao years. In the early months of the Cultural Revolution, schools and universities were closed. Primary and middle schools later gradually reopened, but all colleges and universities were closed until 1970, and most universities did not reopen until 1972. The university entrance exams were cancelled after 1966, to be replaced later by a system whereby students were recommended by factories, villages and military units, and entrance exams were not restored until 1977 under Deng Xiaoping. Values taught in traditional education were abandoned. During the Cultural Revolution, basic education was emphasized and rapidly expanded. While the years of schooling were reduced and education standard fell, the proportion of Chinese children who had completed primary education increased from less than half before the Cultural Revolution to almost all after the Cultural Revolution, and those who completed junior middle school rose from 15% to over two-third. The educational opportunities for