US Defense Secretary of Defense Robert Gates departs for Asia Wednesday for an annual security conference being held this year against the backdrop of massive natural disasters in China and Myanmar.The Shangri-la Dialogue, which will bring top officials and experts from across the Asia-Pacific region to Singapore May 30-June 1, has been dominated in past years by US concerns over China's military buildup.But the death of tens of thousands of people in an earthquake in China and a cyclone in Myanmar seem likely to highlight the need for greater regional cooperation.While US doubts about China's intentions have not abated, Gates has taken a less confrontational approach toward Beijing than his predecessor, Donald Rumsfeld.