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: "intranet.perec.columbia.edu",cType: 'managed',cRay: '92262cb87dd6899a',cH: 'Rp3oD.icXvc31RYNOjXH71Ly6bfYuMxw4fjjkrSuYMc-1742316056-1.2.1.1-cei3uVAxPeQI7KBn5G9n_FCbU5ZKgZiyxP_vDTEsKo4UqT1vMlvrMUbVOgS7Khqc',cUPMDTk: "\/?__cf_chl_tk=t0BnNT5OsnZtIaEKU767bS2dRMvt68yo7OKwkJnqC9w-1742316056-1.0.1.1-P9jXoBHO8TXjQ_RXR8hnCZqmu17r4QB1vr5UnYru7mU",cFPWv: 'g',cITimeS: '1742316056',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/?__cf_chl_f_tk=t0BnNT5OsnZtIaEKU767bS2dRMvt68yo7OKwkJnqC9w-1742316056-1.0.1.1-P9jXoBHO8TXjQ_RXR8hnCZqmu17r4QB1vr5UnYru7mU",md: "QQr_S08ldsDRLdQK6XQ_8UZmKW6JRW93p53uQHeYxGg-1742316056-1.2.1.1-XnkwZs62quFl2BvO17sc2skxO0u.BU7lEV4m5vLGuxqsiL7yOC9AKyP.3cmk6mrE94FoCmpEzQlBXmLjZhDKnYnHcgXoujCsTkI0F_ku6x4cR4zQYZ5nMn6hStqLGhOt06rb3q5apPj51sZq1XZ21aUsMHYoqlxfUokemDtPCWb9aR.9fpD8x7rXjZft3urYQ8MmaJb6dE8NjILshDP9tbsSgZYTdaNW5Xe3LpXiHqIEKtTtimpK34EpaRLTpTfp5VwFqdnQq0RPsSUbIy9gxKWaeAck8olLlfeEeMtoJFFivBq.CmPyImKLn3pl2VolQJJhw.UQWPt5MBj1IqHYfQwd170Pf0WIMtqB3Y.gvQX8jegDDgTemt8mVMA7_YcmI0j84pG6e2iG.ct_LPbeX6g9oWfhl9.xS1aBg5IZprKVu.QfLKfWKYzHfI_8exl9oN2TLxQ425Vhbfj48tWHtHeRJDZEHG2j_zbo4jLD0faWa1Kr2OSnGxtvb0EoGiS5i638uXlz9iG_GSv1UrUwcqz7x2zs.ZUbe0k5tNJOqdx_o_XY5yxSkTO7wEY9kVOgbUCfW2anRbt3soZ3Co3sb5nkjtmC47iQnqniH.HbhufHsH2LvnoAE4jFhrIBimY45rPRWvY0DWUL6TC4EYvJZa.8kn9ooColrNIH6HAmVLIf4rR99oIIGrej4ls9QWRkS4iOR_yPiGURVDz8jE0LP.zV7rMUqCcg9ooekXxJjtB1AjDJ4hG5ngtxadM0z8ulQkF.FjyrRVlni35Mk77fnIn5jlubSM75OQrYmwZI2xb_SMSLgcgXWoaWyiWPogE88O0eWKTxKu5p9fJOmXK8rhcG6rpPO7iLymtnsvWjCkMQLfN6zQm6evh0KDz3Ge7dxl4ioHmt03SeQTBvDv_E3Yd8pPyFHQTvNdZD7NKF2XjbSWGmOO2wIwtsm05ReaGQmbxRN97IMBYuSNFo6Uf_N4gFWURh5jP.r8DWikdvK7rgbYM7lEEBRjRCcGwarq2s7fzg.HPSCTUXF8i99agAfon6vkLol9nzNjbePNznwWKlapzztj..712iGUlfc_iWfJMkdiyOpgi8KqpbZlHujn4_VHkRJGCc63ozEHDC24hch16duR4lqZfRc0VcWMLYydFBYqo8wZL1Fg1GIXeJdCKKyWhCQi7uwsbHCSrTtXHJA6tdeuq6pq9zXQRSPrTiRIs7Vwcm_nBQTu25B0vFWA",mdrd: "PCNsC91Nhi9ctsvPlDz5JFmfP59983yXI6JjDZXy_9M-1742316056-1.2.1.1-IxuoiMi45f2eLGtVEhzhgYGaDHH.xEBr7nEbZc0sW_b8wun.o9wCPsa.C7767CP_xDwcBRqDBdTn1vDys5SOBnBKDDoSMnp99BqhatYrBau1VEG7H5JsPItuJra_Ot0AcMvP60S810ekLfrB5VNvO1oyfUXgTIYck.r3U13mqDNn9hMLUSpqbay5kIH0Fp_Kav7L4BQCC3LJoZMxDz44Dut_Pj_UUgxgbGVe0bP9VEL9nRg151XWRsbQ.F9VJAXWQx3nyG7VDRIGJ6NmawUtNz1Qk5.eMUbpmoVaRNhcpg305__BU4YbWFLmzbmuoCXebR.oKJOqLwILbAuR6jQyCt3CU3zZABLTsphB6EBWvzKIwKyMA9zwdBtWrg7X9.B4VmtliqTjThnmAUX1CdnFlC5p0Vf2.ZDPbIR_H1YSb1ywjlLLjPVoMKJnSEjv8RQesMlT3TLF2_CNdj0QjEiBF78.ExUitiZkROK7EMnBoC3Si.EKnkjWsHvnOay3ywtdo6rITHemIFxxWzKmR9q99VZPGoQ_6ac9tdLwEDSv2tkAIXeXxwIM_1J74ByompeQuuKxd3dgjps6TRras.Z6rJQbno8khx4s.NSNI4zOPrg5v.mN5UlioRKtUEsP8rlOz_80ZPp9WVOVUDqpv0V0FzBow_tJZVNX7VEkQ.GBb2v09ps1vU_gLl9ohQDhbQY6lI4q2d_w6S.0bsjTOkpH7KVvF92pi2NKl_PyJX27GERzHO.wNAJRXFNzlpGTUJRZ0yUZ4LyE_hsxJB8wDzQRgzN6.2GPtvJbvxIoVA1itcMF6k6BnhoS35nz5vAmh8xgDSUctJ3rgKLbeSPC4e1Zf8yb_cxZPysJssYG8AWA3xQQM6Nb8DB_prY9oXrL_IVfc.pFeznj5cN9QYRgx6dq6MZETwde00jY1wC4MvCkFF2lkk67SSIdgSdslwBBKy8_avpkiN1C.JUycTVOIuzbPMXNPy0XNHmQHb5eD8KKlu4nL_UzFkXHTtTT0XLP9XYqlbAloqQrDZANoRAnxyM2I1zTLDrb30D837DHad09nopAEgEmKGtOCLmegBB6vr9iW23VnqCbJzWKD9oe8SXC3oJyucaY6yAYTgNp1RhL71ZX6o98z0.VfJHqcwvpXm4eChXYwDfXM1EGMfMMLjau.8KH2GNnHAKBRdjCYaryJhgPsfeX.oKT11X1Ikm8b2mXDtc5w2m5RhSbenvoOU3n0QXF_i3txhHxGIv9vd9YwmB3v0_cz5GoeKL0p7f7LEbjwhtQ8yecKRTt88Y2Bx4FZmI0OSPcDC0m.aQpXnBy48UjXf6kL.31WbOFBSm3bvYN0F3QgG0bKsIklzW.FpqDmnb1KjhV6XcNouMrCzbDa3tj40ZNF_aj3j4Yrs7J4xL172nhQ8aJnlP4ArMSFKNw2sO7s.aZ8n4rt6iQ45cV8sLqnBSFvWkE7_BqlONUWRgAZnE9dsQ04sbCzBvkLAwcZPiToQ91F7wHawClbJS2AIj84bEDdczqfMWLB2cZnbz3OAjj8jYw2cDGcTCL.i3kjhQAUsiUEUssiWBrg4o6ZgzxFtqR57Q9v0LIgpKXEHQ0rSi_lRqDDwrtwI6TUA3GmDc6Ofp2M9pJqAdeRiYcUCJXptUvwXZOtvm.lAAS7V3UJg8AdwTRQhq9fzmQoH_k3jS2XCZjYs78wq6avd2390vqbiu4m_iXjolujSmrLteXSRsd9xKvy_4gG5OWThaDAHON5sz8EbcVr_wOGHfM6AjG8SVkT3.qDH0SK.Ra5ls1mvLOmImGI1a4e8S_CAJUCB.GmyHob00Nhxj.YTDyhv1BnDOXN5MRpONjU229XXy_7afb7yt6TksBOUFD6a8H.mfH6hTriHzzr5z9rdIIWj3Ne4ByuNoCDiEwqBOZGcH2QvVun0ECH9bK42rn7D8fKw8KNsyHH1StjAIFlH_KhADQ83OilPgeKEhV52UmMqXTy0VLvgCR8BkG8IFJTvJ3wMq3sVuGETwdk0yrrjxMjoEBJRyscQ5UsOSMiP5qoEtqbWkwNtvosilHtXHZHIZXTAt9tgnAObjb2F53D_rKw7kf_8O2O.UgK7kqXdO._D0P"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92262cb87dd6899a';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, "\/?__cf_chl_rt_tk=t0BnNT5OsnZtIaEKU767bS2dRMvt68yo7OKwkJnqC9w-1742316056-1.0.1.1-P9jXoBHO8TXjQ_RXR8hnCZqmu17r4QB1vr5UnYru7mU" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>