CINXE.COM

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="390"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "www.pnas.org",cType: 'managed',cRay: '913b73ab298a403c',cH: 'Fs84LbA2qRDfbnmkrkB79QeGBIoG49q2krIsFLGgrjg-1739854808-1.2.1.1-M03ws.fVuES3o6NPfbFbe4xpFthuYEp6wWmQaErclFRgmJELBQsTBHpkYT1uxnb0',cUPMDTk: "\/doi\/10.1073\/pnas.2209109119?cookieSet=1&__cf_chl_tk=AaLpR6I20iLV2Dghy9dYllZrkEx9TJItx77YRvyxZvU-1739854808-1.0.1.1-kUNySepmAysMkmDlQ.DYAHQK425iKx8gqR8MutiuJoQ",cFPWv: 'g',cITimeS: '1739854808',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/doi\/10.1073\/pnas.2209109119?cookieSet=1&__cf_chl_f_tk=AaLpR6I20iLV2Dghy9dYllZrkEx9TJItx77YRvyxZvU-1739854808-1.0.1.1-kUNySepmAysMkmDlQ.DYAHQK425iKx8gqR8MutiuJoQ",md: "RnkFY5tSnzKtwI1m5MFP2VJ8HgXjoPnPJhuR5LGHpcI-1739854808-1.2.1.1-vp2UMbfPvQBjvVIvmN0m0_hQldKJgBozxdqNan_ruADRZfe2B_L2rikHf03ROed.wNs_km0yoYMv9CC9jFU_G7Ui5dZjm9eqnX00AfTMPdofZQ8adHoc.x3LY7J03P.sGb2fv_PeZTt1h3j57VRs58g3WgF0R0V4ZrrjFVKK9k6nZrd6JColiMXiWC2MN57vPgq5nE4KBq9Zgfn6hvSr0D5Qp_tOSBAS5HyQ6CYgHPImMF3j7FpziVnqrBBxdHcx4KOVkSGVtZR9ohPAYJo47Q6tpYfm7DjAlQdC5JxMMB4eDGpOATAshsYddsaY_HA5QrTHv4139zoIhpfPCM6eREb340.ZgTIXhnG8xP.DlWWVzzb_8GfVJ4E785xoiv2E7LTr1wLN9osCNFvJTnKG6uIC1JAaE1SxH3gy5UXsoT55eF4ekvBOGLDOUhGOwcAJmE8WTnny3XY0wbb9uWNQA.W49.ITNcfDD92HCEDg6JdXUAWhuL3KQ1aRyRZR8UCWDo_bdRg11K_X8JXqy6G4aGtXBIvG0sl2.5E5X1JGjq4qeuJ94p40Z6QANEpmH5TE6Vf0gQfJgM.kkgKEX_OnbcjIyn7hJU5bBOzjbC_naG8zrCGVU1Uuq_2D1YBmMoNOwtTZ28c.HSPboW9dz8sE4dGcX3DR2ScbPT1Eyw6x_P.WNonFJEVmMWdgi2XLzxW.jE3ihSjfXWkIZIKuHTcynB7Cag.metSj6gG.YQJ_32ZV0M4CC781QeFar9ah8aaFE0DwPXNRwp6uk3VDWPbBUm6vVz1PCAIJnz3t6DSpW6uk.HR2X7RQ5OeUcHe4bc66oD7jSR9ce0pVL9a7j126bo76sUonSnvs_kL1DXvmn_WZFPNTydIo5f6rLYjYIDTdARHPo7OAwJXK0_xfXeO8ST_b.QhV7MCkQ7GuNE23FBPwm50Z7QYO9eNoeE9W5YdnmG3b7TpofsTRif2fO3_IhvY.krhIICaAcU1B7kQjYaP7FrTvlJ7vkqx58.4yvPZ675OF6gBCwUVtx46.NcZzOpCYvOdektunj8OwOoQIPasLr8KsohK6Yg3xwelP_ZqtuMnSijAKIHlyo4RjiToDJvEPoeO.LIUW8Vk4WkXCMEV2UTMJRYvMGwx0jJi4b6N1N.0wI2nHCHGdIAxa5Zpqe9q0vUDlyfvpNh.ymTkV6TbcOHOCGzAARNBW67jUeS4fIU.QT5sY89PMTyOXnkz8quHgqG66q_dRWngOZlJg8S9_TcivOGqpEq0L3MWEH4Xt5HFnylRpYJ9KNKte5k4cGggOifsC4HNqM4NGSSqzT7VliG9ZlqM50SvBtfoA4gmsZj7TBpdRW4VrpTKYxgkzXbPOzqjZx7WfHIXJabB093Q9hJI88vUtE2YsGEvJXJS.DqC4mnlhJqYi2heyq6p532KHuGXXWlAkmUKr9Tud0V8I4J0qBiQ1Qs69qg5v_lG_Nk4c7WTT4hQgzo_tmup2PREkvpyy9JRY6yutnQgt66go_1wvpBshjlea9N__h3kkN4JWqntw7W_bb.s.E90qjaKQ8ClQPMx8qFlfPtsIkuIqBDxIpg856bZvSGHMOjVmtY6IL0c3m7Bt_wTue4b7ukYrTUI4ArwQHEaYblrup0tEgkHxLRkhA2AJqwljsSla95ZaXJG.uTlEo91XSQ2y_fiNnPk3.XY_7PFQiVHjuvoV735guGrBj9NVgpQptBCIciLdA9VOGVp3JI8.H0aryQPe9OluU.16QGVGFFqr3ggfeKKsW4knvRPjVa.xT2mcmT2rfIZW7nzYuBsz07YrorGAFOZ5vYV40guYYO_5Acv_6s2C4GZhdpdeQC.plqPzgDR0UcDa3.lIZgvuuwI48g8hKmEeVaDwKfdILwhUtuTO3PxyfjgbEGqizmIGiVXeL3ioItA0F_hsCcGCglaubHR8o_HoXjldUG4ZYhX2.TBonKnCqLoPuBGQ17zgpnIZRG43Ut81Zs_aD9ExEN57K._R7J9AjHlLhEXG82ofABAPrRevGi_moHywfe1qeqgf.kWKtZavzlFGk8pL68FWR2mwTiY4NuLX54rTdT4QbIW6Tp9gF.ifT3nkYFCEP38Be57gHUWqJUHx6DMzJ639ctffHumVXAweIZrWeNZob1CPg9r4ZsS9REjPyw6u47.UNJFRLawS6CdoFCiNHNNSz2ujNkF1CxEuor5XYOwCrWiHuHodtVOu3DorutBw59LOySiDAG_bKYQcuJopGG0tX9dIvKbRy8STTIukmMXKWv3RGY27K5GBop9APTlAB_lSzSItfAmqcW1fQlNbv_zYv5hLGEgJELzAe70NEXWjDLV6PDI6TwTwG8GbqfpHqT2ltt2.2yXbKa5dxFq8HrPRmxaMOYFPshZCv9tcclSquiJV5nUyhzV7SxGZrVCuomPu10g0nE2K.kV_Z0Eq.DCpPcVvFLmyixWeqoIVbiUFlQAuom8Zr0FLM5NMkDd6WNUW.ut2R2qnvntI.X30lRbrV2tpXg9Ogi5e5kwg0iXg76JsSBthmTEBMYQ9AcKoySRGH5KgxzpRwippXUbmFBLsBSPgRc8hyyo7U.7hnUvzJQru7f8eMzfs3Ymbd6yHcajo",mdrd: "6m18s5iAtSSh9AVY05qunmkBjj28rSVneGlDijvHFcU-1739854808-1.2.1.1-itaSfXvUO1wd9yEkA2K.5YHIJRkHY1e4hlxA3B3bK.k.3hpc0O2lf9JpHowYD11Rwvj.Um_LioF6I78kd1X9vAu.6Qjx3MSRdxSwadWo887AKe_sqJWNwF_GDsLcBJ3CzpS1B89ZsxQkV_GbGWzDKfmUVm7yDB6KEVWoXMubFdSEd1DK631L2oRQFH0UrrzhIYt8.sCi8txOPm8hqQq51aFAhw0KLUdiFTehama2ZR7OkUotINQwGN4ngZiiDy9MTsrjDK.SIjPu02u_1M2v5hAEB3I0j8F4xS5g72o2HxcJr3yjucFGN6U4D_AJQfxkixvuPzPxqSFIqYALyx0RGrc3PkoFTO99AAQ0deEHvcJEKuTdXxoDXTb.PmMusBhOZGt3hBRnh9oQTMEgdvQZBwkiyMO_2A1NmJhbK8a9zA6Bauuu1frh0rMPniUsd2PaSUQTwYVJ4dJOaN0pWY2IEOv3TteaVdYb0tQfuyL5n.4CiNWlWIWBbMID6Ln2K4hN1NSU7F54SA5LZ8KAVnCZ5CbRx52y5P5eZ1DsXMdgVKvo50lyshn0ZdDOkb8Ecllm49cCmbjKFGPDe7o2czeRMUslspVHOq1mbXQG35Pyaynf4NjGQhP2zjSRhV4pa2xdnZv0Y5DNLnCQmVk9idDbj8Qvd3YYxDM.OcDjrUlNl3iLqVks0cL3zVsdVOQxIGex6BMDsSMcM_U3M1pOI1NxFJIfJcbmmrFE1NMP9fz_F2mDbYGCRXiYJLGeSWkDeUCkSboydFWfK4AuAKKkXd2WBOwDzeiPJqcLptRi.xm5iraI9m3LmXLmmnuT_XQWsMMMHlP6k6oAlR53tZP7LM32WnS9irwT9Xz40gWEqgjj5cHxCXjG2e2cuKmXyK_TbsegMXfpINOKNLLdB4_G30JnBiJBz_Q8DvLPwHSITrBfzUdTnyaHAbjaLnhoRrt.s4fo567riT2XGfaccZqCDukqO5tZ2nNsOS9Ic9BEjDBoJxXq7XysOU7SUAIBo8.ajwKzG51KmN2D92G740yt_cmA.8ywOYkmlRuLxSqsA_wPRpRR7y9bPrs6NLutFBGOb01g84Tbao_jZtrLQ3XuQwQn9L5vOoYUbJJh9KQIBdMkyt1g3O4HTToDxeJ33_WaZ3a7ZqNZiHDgkO6WdeerVFhJIbVZA9UfNPyIka_ldT8_uIjElejIIS1vao00nliIQy7NKSTwcs_MpqoGFFvIgiEpipSL7Yn8Y1x.2.4eaR3HJtwp7UB9z.eaahade46Hhkb7Y8vyNtV8AET6UqmTLDgBDR_m_n2ORuL6wA8efjAE.3TZMl55wTyAaDsHIyFhyT3UKzHhRyNNpKLm7JRwNwvzIiYpaQlF0G87fPJcm5fS4YlzYgP9hkxIuO9MiQS1LlKL.xV1AbhqaZrU6jcRsdjdZRM_9kSSUGphRnpjgZob7J3qSrnE0xNBAe0JKhOBCzljSRuBeeePk2D5qwxtpsYc0tobkQ3PpRBO2IIOYq6tb2vqkHPkOekE8r22IdKm.5ht04u7Cbg_xybHYsNaFNC8Zppfd_XnDC9UAkix1B5hpeHaUjbqxh0eMcFEBbLr5xyMfP5IanDc8xEe9oDxTiMnh5qdNRuGJwxYB8nko.ugF0h1MJAXkDYwCh8UP9Dr9Ea3AipFusROlMxO5NldXL.lWBzj2gk9cwrIxwtxDIPQchNrmPV0gpGzHYR3Nd39t1NlbPw6HlpOAo4vnOdmscmSXSwgL2jpOZnoV07GYc7uFl7zVbB0s5cZbcZcEzBaigKW.3p2VpGJ5EFf9mEo6hbTSTkDH0spzdwhE.1uE_BfSjvi7z1sVBx.PWZ5iDcFV1oundiZvSUwWfX5Y6kiNOptCM4ta54yMGUpcvEslMwceoZuWpOgjz64AtgM4VNUZydiiweh8J38pKUpNd1z.VZddxan7NeIbyIkS6JiCT0t1ft_MEUphqYB9tlrZXcXhdyS"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=913b73ab298a403c';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/doi\/10.1073\/pnas.2209109119?cookieSet=1&__cf_chl_rt_tk=AaLpR6I20iLV2Dghy9dYllZrkEx9TJItx77YRvyxZvU-1739854808-1.0.1.1-kUNySepmAysMkmDlQ.DYAHQK425iKx8gqR8MutiuJoQ" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>