ATTTEMPTS by Myanmar's military to end dissent are turning to the virtual world with internet blocks and arrest warrants for online critics as big rallies become rare in the face of relentless repression by the security forces. The Assistance Association for Political Prisoners (AAPP) activist group said on Saturday the security forces have killed 550 people, 46 of them children, since the military overthrew an elected government led by Aung San Suu Kyi on Feb. 1. There were two deaths on Friday. Despite the repression, opponents of the coup march every day in cities and towns across the country, often…