作者：Reiss, Diana; Firestein, Stuart
作者单位：City University of New York (CUNY) System; Hunter College (CUNY); Columbia University
作者：Tao, Juan; Bond, Nick; Tun, Nyo Nyo; Ding, Chengzhi
作者单位：Yunnan University; La Trobe University
作者：Wagner, Michael W.
作者单位：University of Wisconsin System; University of Wisconsin Madison
作者：Wang, Meng; Shi, Songlin; Fineberg, Jay
作者单位：Hebrew University of Jerusalem
摘要：Brittle materials fail by means of rapid cracks. Classical fracture mechanics describes the motion of tensile cracks that dissipate released elastic energy within a point-like zone at their tips. Within this framework, a classical tensile crack cannot exceed the Rayleigh wave speed, cR. Using brittle neo-hookean materials, we experimentally demonstrate the existence of supershear tensile cracks that exceed shear wave speeds, cR. Supershear cracks smoothly accelerate beyond cR, to speeds that c...
作者：Guess, Andrew M.; Malhotra, Neil; Pan, Jennifer; Barbera, Pablo; Allcott, Hunt; Brown, Taylor; Crespo-Tenorio, Adriana; Dimmery, Drew; Freelon, Deen; Gentzkow, Matthew; Gonzalez-Bailon, Sandra; Kennedy, Edward; Kim, Young Mie; Lazer, David; Moehler, Devra; Nyhan, Brendan; Rivera, Carlos Velasco; Settle, Jaime; Thomas, Daniel Robert; Thorson, Emily; Tromble, Rebekah; Wilkins, Arjun; Wojcieszak, Magdalena; Xiong, Beixian; de Jonge, Chad Kiewiet; Franco, Annie; Mason, Winter; Stroud, Natalie Jomini; Tucker, Joshua A.
作者单位：Princeton University; Princeton University; Stanford University; Stanford University; Stanford University; University of Vienna; University of North Carolina; University of North Carolina Chapel Hill; University of North Carolina School of Medicine; Stanford University; University of Pennsylvania; Carnegie Mellon University; University of Wisconsin System; University of Wisconsin Madison; Northeastern University; Dartmouth College; Syracuse University; George Washington University; George Washington University; University of California System; University of California Davis; University of Amsterdam; University of Texas System; University of Texas Austin; University of Texas System; University of Texas Austin; New York University; New York University
摘要：We investigated the effects of Facebook's and Instagram's feed algorithms during the 2020 US election. We assigned a sample of consenting users to reverse-chronologically-ordered feeds instead of the default algorithms. Moving users out of algorithmic feeds substantially decreased the time they spent on the platforms and their activity. The chronological feed also affected exposure to content: The amount of political and untrustworthy content they saw increased on both platforms, the amount of...
