With latest North Korea test, U.S. again seeks elusive Chinese help

By Yara Bayoumy and Yeganeh Torbati WASHINGTON (Reuters) - North Korea's fifth nuclear test, its fourth on U.S. President Barack Obama's watch, leaves Washington yet again hoping that Beijing will crack down on Pyongyang. Given China's longstanding fear of a North Korean collapse that could send thousands of refugees across their 870-mile (1,400 km) border, North Korea analysts said significantly tougher Chinese economic sanctions on North Korea are highly unlikely.