美国科学家探测到一颗迄今发现最年轻的凌星行星。凌星行星是从一颗恒星与地球这类观察者之间经过的行星。迄今，科学家已经在年龄在1000万到4000万年的恒星周围发现了超过十几颗凌星行星，但却一直未能探测到更年轻的凌星行星。这或许是因为这些行星还没有完全形成，或是因为人们对这类行星的视野被残余的原行星盘（新形成恒星周围的致密气体和尘埃环）遮挡了。

（北大经院）杨汝岱、田巍、刘政文、吴群锋 This paper introduces strategic interactions into a Ricardian model where two countries optimize trade policies. In a Nash Equilibrium, we find that optimal import tariffs are zer ...

Chaiwat Meesanthan, the director of the Institute of East Asian Studies at Thammasat University accepted SFC journalist’s interview and considered that within the Belt and Road Initiative and FTA ...