Beijing has signalled the start of the summer break for China’s political elite with the announcement of retreats at the seaside resort of Beidaihe.State news agency Xinhua reported on Monday that Cai Qi, the man often referred to as President Xi Jinping’s “chief of staff”, “extended sincere greetings” to various academics and scientists invited to the resort about 300km (186 miles) east of Beijing.The report did not name those invited but did say they included specialists working at the...