LMAN, School of Mathematical Sciences, Beijing International Center for Mathematical Research, Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.|College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China.|Department of Biostatistics, Yale School of Public Health, New Haven, CT 06510, USA and.|LMAN, School of Mathematical Sciences, Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China, Center for Statistical Science, Peking University, Beijing 100871, China.