CINXE.COM

Just a moment...

<!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: "direct.mit.edu",cType: 'managed',cRay: '92a6e029eb70d4de',cH: 'xsHoRE70BkwRFm6OZsDp17ttrIP66w3WiAOoYAlpzv4-1743665583-1.2.1.1-YCZyFIi_7E.rjlWgFpt.Xe15UxRXRMvxOg2fetU__S43Y2a9G18r3Niu1ZoJR0Xn',cUPMDTk: "\/pages\/cognet?__cf_chl_tk=o8DPelbSExK3HIaMLIpZhJeUc9hYEZa4EeYVjQQVlMk-1743665583-1.0.1.1-.iWQH7OKmCu2F33JNqoFTCKAfqrNDN0V5FNO8IDBVeY",cFPWv: 'g',cITimeS: '1743665583',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/pages\/cognet?__cf_chl_f_tk=o8DPelbSExK3HIaMLIpZhJeUc9hYEZa4EeYVjQQVlMk-1743665583-1.0.1.1-.iWQH7OKmCu2F33JNqoFTCKAfqrNDN0V5FNO8IDBVeY",md: "TSPxbwqK.csBsxd5alVAsHTqEBjHD33yGuCCYYyzCxs-1743665583-1.2.1.1-TDQCgH6d8YhrasR7CQnNhUXWLbo6Y38HmcKtKKn.9y2TP6X.BXdRyEN5FC1xRxe61r.q4vz3AmJHntCXqNWOwFywxqjhUdQDAxRWnAinyb.x1u7Mu4pWzAn1xO3tZZITxupVzbQE45lc9g2sSLbwDq6kUv99AfHlRHlZ2DkpEo_ZFMyo1f7StymkOwivGwT1UUtDj6nw2.H8aG_3XUy6vs_JekJfpaprou_1NcyFJMFeP36o31BQ7la7QaODpNuNRZ1iNy4g8pgcBpgCJE_C_7BMYuZmUiKdT2snb4V26.SU6zmY4hKyzflGUsD6mUicVoVHqgBlkADrE3CpxAoJkPh.y8hG6rdY9NJpWJiJXkRKAJFVgZx6G05cwNQJbI9rhn7t7Lo3G6lueDQFT.8K7nPv_UQmogwIWnfoOckz6PK.tEA7R20FxizHZEzg0wJCiftZTrv6MIpPuC.NEaSZu_hW6WeZ2pxJjuMwjwlOPftzZS.FNA9VOEwNhBKaV480R4hq25sSeMgf2vHOPBm1nkkk7LI8K7tC8QeIb_whyTplHxGFIza0LvVsGXlXmZ_2uyO39P.acWD3tLonVMDsfa4pxXEvSABuc8ghe7lCDmp76zp.jzxp1NUV5YbBckQgzzO2CV0P2lXTPAkl5JfSlCF4uAijZD1LDjXfmLIaj.0x45hLMy2agP3Ox8t4ayB5uyprMJ3EU6g0Pa1vyozn397IHVLPQvs9494TGO0.Tw1F4b33f4g3tR02SY9pFWpS8vSNl.TuIBbmyzU0g0TlE11wlEOr3IDy1tsCB4w3DNnwO.GlgdFu4nWiDWXjS_symBS.yGzqKHJTNg4QEhBYzfUXQzq8TO11FMLBJ_rSnB3C2e0fdkGP0mBQ8LjC.2z0yd0uMBgSw6DuZhs2TU1Vi4kVLpd.2AUxulPgAf4eisogGT0THd.a8IMt83SjfzayUcNH9lpp45Dw7o.h5V1PKSjn_AX8ZkmuSEUEYYKi7LQyp2.hvA7.d1It.mLOddnfOz58zUzHx7qz4YHTs_d9hEduXaMzudpM_3Xf8I1zKF1KCEVJalcdVdaN3WvULRi1FGIEt91y.bhOWjKnDLOZOKSmKjfLokeqtCKdwQO7qaBhA7ZWTu4AtZGtJQYl.nfQsPN7A0FIA4wqjRD_5e24HGx6FlS8tSDL4bcg9yc5sEzz0aZk5DYo.7lXNpfDSe2tIdPGpgtF9KNmHbVatbqLbDTLbwvW4vBeAs0fADxQBpg",mdrd: "5.LaxZTaCB9sGgV2kbmaggeQD7a0dY..XfiGsY4EG3E-1743665583-1.2.1.1-zNGu2Hrqn93bkWVvlwLDaZZhly1aAbohDNS9HJoNTWE3_0wgtD9k7l8yTYM3zEBzatOBS7HFfYwyKXZE2jwKmtgEmNfh5uaxgAXLPTV3gGhdsFIbHRfUp1fnxSAHrMA6IoNL5TK_Fcryvh9Kalknbr3feZlPyCIY4uQIIhmj6wEDrCHTSbntivNemxTkNxKhy2Vk5_EqLrQyzfdLasr8.qvd0qgQmh_H4gTABV34Q6vDwXU3VhMHKL2RZpItB0kmDZ.afWTpiZQWRBfuFae78iyWzG7HEKeR1qChEfqups5yWoKVPymVEiC1zDEN_oRgUQAdeLWCBF4allzHMTTreSq1Dub0.sqF85T6E9RLLMOe691VkZQvMPafEUdL3_lODSINyZIFOnRBvdOqhFushKR2paNRUZ8lB5FQUWbfQT3Rg_vSNbuO2.rFysbFKo.GXmPSDHCO1fWtK7knJvfXaDhkLJwk25FRj8n_dB.Rv4.pKh66LVPr4UvGn6mY.xcSFuzeZ.yGkbHHG19qM6BEM2XBPbUbiJRoODY5rQNZ89I.9MekgChiFWA2zeEYe8D56.UeqZBC0juj0q6wzKGqxGgkHCiZmOQ0urYhRvibk.f9kJZFlhd.JLNWpTLzRbqEL9J3tJ5e0DDo0o90OqXMypJvnkpt7krem26Pok7ipsc658jXVNeqMY.kPbWlznVqyFAqADb7hXxGCDnK2OPDM9_mVT3SzBCDQMaourEeoHqGR0jISxgdkjK7qEEf1.yF0OUGGSRipi8jlsjcCxan6U9PuL87ZkCELxiZwIj_xMK.sdWDuf2kxqLO2hy2YdlsIVJ8ufVWhmUf3eR5IKSGmDIAR19T_Nlr850LG_yFsbpSqUSdF2bU2JLfptCi4X7kxJk3kMGqVaLOJPSX0Py.fBrMn1qn0Sbkwc8l7TbLRj_hbqoVabUbgoLak96lRDguL7Dx7iy5Wfyjsdd83rLw5sr1VwTS1.215LN2TwaqnUL4.XjgJEUkDMG.0eAbCM7sHhSD582_5BavXRSKPf3VSbYXvfnyXTTWJqAMTw11DJ_wcCMxqtLBwaVbhLzaPeYyhqAKBNqmHPHmexpX.Y04eNiv6q7cXmLPxyr_9WRKCdgExUCwc88NY6dIA5pdJJ5XEdVLOkS78MyeII98HdT1h4sI21bqWri9GHM_kt0TDRS3a6V57Rm7wPFTCXbZ3Yi8XS_IYsj6j.IKmSd8ppJ.nLYF0.QqjjJ.GHpidtrm5cPRdmFxpVc3wFWn2o.WkLQAijSeUJBPAcd5CA.LxRR6pbFgJW4RyptUhwOIHNPZz2r0JjmkET7QIcX1iCOKsCIUGUvq8VrxNnkGGazTKgUG0GZ7KW3iCkM4ctlnh_BMeenOj3oZWrMGXnTvZbG_lRbbUBUzKXLNvDS7DnUI.ci_vOLEo94MyeryvU22kNO3mZsZk6IqjmkP_YuDPj33ZCVBu3QZYU9Pz8ddI889Ly_WUvj.M2h7vuBm1Ba6lvsJNAUZ6bv7wQHbwducIK_L_Exy6hkab1ScZX.OrUFFTRb4H9QTF3YGrZK3LXGwmRgfbCRyjKWQV3TO.pflhtwm4ViEuuFh0_637cuwWT1bdTqsXEyDuad0ODlTtac.cUJLQkbuWqUD0rRZotvg1NFDv6lQHvC_WVfXTKBZj33Ld_xZ6pqUZVB_GA4IXEAjtKMTLhjq9YB7wx9IlcgJZCuIrYz9AuiNKbaHT4DVkilobYixQM33peQ4kmiMTwg9acTRjffhrZ5OSDmugygoQHfJbzO6aCl7qBQ2XFzQTSD0XgxWsvhDvdUUXG4Wcle4jZdhWOGVnwsO1_ffU1H1nY0rVIY_hG.CAwkqimqMHaGHX3WHpQLpHPv.Dz3wCqY1z1Vs4zfXxGaLofwanQRJdmajtn6.vpyICfgixqa4j_AaWfYpgqXcsg57OX23J9w5O9WcFS.h.LwW0l10eRtKrWXyuhDUFGkz1TyhZ6uQm2BpoGYryMW1h38GzTX6IjctpxUNKhu_369dENlhpdjNiLcCVAv99Dsh0i_.k7nY.P4YIIumnQ"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92a6e029eb70d4de';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, "\/pages\/cognet?__cf_chl_rt_tk=o8DPelbSExK3HIaMLIpZhJeUc9hYEZa4EeYVjQQVlMk-1743665583-1.0.1.1-.iWQH7OKmCu2F33JNqoFTCKAfqrNDN0V5FNO8IDBVeY" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>