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: "perec.columbia.edu",cType: 'managed',cRay: '92299c5c5a303f55',cH: 'uInyk16f7fGNN_bHIAsZqXmgCXctuqQVllna.e8bAO4-1742352086-1.2.1.1-OhYUcqZ8fBfiXtWj3hekAisWmoiHygENODxTyMRp7F._.9OZ5zHEvtIeVS1oXTox',cUPMDTk: "\/fitness?__cf_chl_tk=2vc..8OLiHA10yCBJeEa5vbyjai4jiDQYPDd8Ixl2u0-1742352086-1.0.1.1-lw7ttv08MROjUOMrN7mFvcF78ihEbsgt_6so3iOszP8",cFPWv: 'g',cITimeS: '1742352086',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/fitness?__cf_chl_f_tk=2vc..8OLiHA10yCBJeEa5vbyjai4jiDQYPDd8Ixl2u0-1742352086-1.0.1.1-lw7ttv08MROjUOMrN7mFvcF78ihEbsgt_6so3iOszP8",md: "CpbUHW7OyZzflqzxMnZ_YH4W1CbYFzeR.AznffBRnas-1742352086-1.2.1.1-es38TS0QSaUiYaHueBr.Vg7AkE8d2E5_35VbDwQJe2ntrQ2KaTWzKejKOtxE60x0kSg5iuGGKING0s5UFdgg_nKSTPCLga4jxikp2I4tcjjWu0FarhtsQmsOnxUtPRtrj872VY_VsFBE8Mzjh2SihixQT1Gz_sJYrIFCoFqKw8VJRyPqn8CMT76LVzOFeE1Hm.6YrmxVcH8_EiIrA0v3yhO2bDg4gZiCO2ZslxCuG69VzfusX2AETFdYT4EBBsdUMQ8Dx4dIoLZyANzqaHnN1l1Bni.GTlBJFekMehXAcnQr3Wuld3.2aBi1eC0hUMr5AUykw9AYmaGPHrXZOR3WVwc3xdr86EF_Hf.6_iYL6HKEjAFbqua_YjAGZ2xnH_FKdHFfQM0YQKSuyElK6n7TLIyfeIfnZPB2yvqFTvntEfT70hF0uMHsLtQZykvSjBErZkSlF6ubw5iPWl4lsoweUIL17baIdEE8nPu9jdo81txsMx_bmAcg4VsHn89OsKO37VtpNbr1Girz.lu9jX4DrvK7ZOvkfmvVtROiwi1dNqSnDmF_ut7irLNaYhJQKrnIoD76qW_qYdl9pmEYU97cA_UFzKWXT2GsseA9YkNcbtPZFzjmrK7bHRHNWEf01EaSWPv35eUNdYPs_aarQnilAyAkmBzyboXr0OOn79eH4BNcCmzQRhIvUz4ywe2gGGJh3W_01dfYzxfG6cdRkD7dzGFltvUCDwIuPj5ZUr3wcYWgaBE2ppF.Gq7Q5nsIgTcoJUeWUGlPUDsDApRsFUp31veE8Obd1Gx3H7flRg7pGg_kzYDSy7JCrJOBq18bYFXJepXl6jN8JCLy8q1D4112TRH51i3NGtsiGJ90AIL77kAbfb9fbCQRwm8YY7Q045lzTsGsKJwiTjCMvX.EweldkOdQl8SRRJKuR1EoNapg88DMv35cH9q87rSHEyx50SW25LeuvNzcR3syGLgUneoEhqy_rHuGHDwoP5PBU7oEowEI_uArpAnKLCwqF3RofC_6ClsNXt0U2d2hvSSuESEkkwm5EaU8LQIr3EjwmCEk6.NsTVfsZLptYdVFDxGnhcZOOoYNk.IalWm35pwN4dJups7R24GnHk1pnEwDOXgJWA857Jvobq48jLGVyl3XQz9flsASL.HiSX9_Pj3eTEYJcu5tbG1Kb1dwTEDeJKQ_HmsTIjXIhgNsCGqp0Rd8P0cSnLbFpcY_QexoS0UgjciZRg",mdrd: "E84.ENL0HLEO_rPxBQRvs0X66rKznFrKvyOfp6hnVPk-1742352086-1.2.1.1-JmtmzM8IVB.mm0uIqajmB7BN60alp7nQjWwXsoo_3YdIdIDfSJGSQNlDjLYLLHvryHdBK5rX.8bGM8AKq.FZh07S2vzTPBQe9W91ZnkcANuwAh5PYf5U5M1CRmoCfsWHLCncY2owdsTsJPq4jqPrvLoS01AzJ_8yafqVMIj.j3HNinWQDJmOGt3Mu1L0OAccPxtrluvxqH4sm.Z4JvX0DxeqZ7B.9VbSQ.z8Ro7UB8K8J5YMXkkynk_v9FjLhF3ZRy_kcxPvf.gQuAI22jczXVGwfHsQXvDWwlDBKSD3FcuO4CeEoASyAgOA_6OPKM09t6052J0qvpfwgDJfVC71JnZkCMGGdPuGze_mcUtjpZn8Y4ektMrhFDiHb2oSq3hvIku6lVnCOA7kZvt40CVxvB19jrbrjUILOcz_VCceE6UkEyFpSomRFDlj7E0uBtSJNvMQrhmpCWwYDFxE7htkIFpHq.NVTSB_0kBc_eAD9QfZVeWZygSKc3qDKubEVk8bPW_U84ekny91KGeXl9boE8oikXtCTifq1dBPdZ_mXIYEGrKbGFAFLom5RqYeDjcD.nDLKEMLue6z5OM5d.tVt0ztri_ASTwfstq.e3MjxSNrIEfQTxh1_lAyymX6YhTcdcOD5Ddq_tiG38ek6WpX.d1u0BtJ78KVKI88sgT5rXixHFS3pAnU8JPfJxJX45VrqL0K0Z0vG_ApMO_ntgdDZCkZ16qhqEcQmZHbp_r7ock9UEkPFh8EGpb5yNx9qDS9dN2RIAeLDBKDO4B9F9dRgvC9gltv5Bi2nUf1L619fdznIEEiBVvf0a72veRSL4WigROhRgtdnKlnx3ArMMLbBh7fJXbi0O6v4L686xNq68Y1xbqJ9TzCxcMCQuosa7oYgypzUSNSgRIIwkdTFiq8GYH_Wv.vq7HG1lpfE6jRN37DzVbCXRMHb19pJuBrMXWnRczEInkf4QyrN.qI6oyPmxFrUcZUCy0s_iRGNWUtNRWsrxI.KmEJ55gTivGCybLKmz1c0OuwrSmhuAM3Nm0e7iasw5cOlplIoE6InJTpNlOLXfJQWl3rwupQQ3yW68L4xeuiInkTfXMd6wo9oLMKzDTfTAKN0.YQgQRGcT_5EGAKI4Kat.Yoj37NkjD5WCJYFRt9g3oUGCWoU9DvK28PRnLQD7nicPTaBjPG7oGFfxUuEWmiGieBscPyc3jDvv277VfOb0U9T_zI5iiCSxdXwdA.z1KPflsJN.3j_cmZuMHDG_F3Ve0NQeu0lEuu5jMnYhk2rzEWOizMJ9EjTdtlbD0_t9R4vAQXKRtezjSO0pnnpMfo8hY.ezeu0vneYKRuMqFO_pw9ptWKPmbQcmVTNrz4nF_vin149p32QVjJBYBjhzrsUOD.UhcsmeZwTaXs8T42PsFKqUpuGarU5kRZ.1vCPIsadQQEC53RK.NPVCPD1.0ovXOt3DHbLZ9IUDSW7y6XeGjuhP3ZFoj7V_Wp6AiTuN6nhpwBWpzlJDf8OKRgyKfmD1jA2CsYMOFdKQWZ8leomjKgNba56jJd.jHzlMCSY3f_XQAPKbXFrOibt.QsbYbbwZYSXpgrBSfXT5k6CFWi6mYpDMu4gVfmqR3VhonYSWMhPLen2l2V0jsMd.pIhaCoJQEAzd9wetAYkBAcuu8QhKoNvFA1DR6J4oCzzbAcSq.Hc__DIanZsmwvQiHnf6hglHTsTbTEOjHGABghSgkd85SKyrdoozZHwSCbwLyI3lF.cFqBXnHJdPAQj3epKac_808CnPERQn.tUlS0r3ByD1LVoOFygWSrfy_LL4DxK2CkqjtrMOe49cYtxJ6im5NZ17IOz7fVbDwlt08P0YB_7WCaWh6oGXShUBWBdPhQi7A83BzSUj6bYE8vAdPt30kkvN8JvIGRiiz5q4iY9ivWo0ELhzwNl586P3Af3H09UU.rNOwO5Rf0vTZqvcF9EEFHT.4_Z4Yn7HnC6rsYORqYNy3EoQLK0zCekfLdIqy1z0XJGrYq8_gItusXfZp8djwS8LOGe1LdpeLNy75RJaGv970CYEszqO_Yvi6J_CDiPW735O7pt66NWetVaZw"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92299c5c5a303f55';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, "\/fitness?__cf_chl_rt_tk=2vc..8OLiHA10yCBJeEa5vbyjai4jiDQYPDd8Ixl2u0-1742352086-1.0.1.1-lw7ttv08MROjUOMrN7mFvcF78ihEbsgt_6so3iOszP8" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>