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="120"></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: "publications.waset.org",cType: 'non-interactive',cRay: '9134b2982c6e8bc8',cH: 'pHX5YBYQ3SnaAHiZDMpRvcDugOnmmhtIxNK6QcfpHsw-1739783985-1.2.1.1-6s7B16CpI_OlY_v3P0Rl52L94uimZaiwvf83403rqFbqSpeBVg1_5aBD.CnzcR_i',cUPMDTk: "\/6274\/harvard?__cf_chl_tk=5bzjwQWDIb1qirSR8QbPUW_QONSGpsNA02UydQeieqw-1739783985-1.0.1.1-dcbT.n6nfRAy_XlnBaauHFZVDvfwSl7Gir8FGEvOnlg",cFPWv: 'b',cITimeS: '1739783985',cTTimeMs: '1000',cMTimeMs: '120000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/6274\/harvard?__cf_chl_f_tk=5bzjwQWDIb1qirSR8QbPUW_QONSGpsNA02UydQeieqw-1739783985-1.0.1.1-dcbT.n6nfRAy_XlnBaauHFZVDvfwSl7Gir8FGEvOnlg",md: "r0xqy1eB7BdIOly_uLauTFzIPGdxBUkE2nUhxoE2GjA-1739783985-1.2.1.1-zy.CdKc31idfEmW2Tl16b6N4zxy.SQ2q7MsXOZ_wNemvl.kUEGoh45sGJxRWGk4a4fZGQ.ijcEqxtsXzuG7PdFX6LVKsnCWubp2SAF5CEk4gJ70a_iPi2hOM1e7d5Loc93f8VU.mDVuPLhjGUYel.hO31q8GQEvNekLB0J0.klpdfhJeA9qkcSp1PGlqaL5jjfZqvkMyNnemrudXAKURaOWHmIgePp5h7GyIg_MUX47u_EuVLlGSpJfvdjYvplj9yxUIytXjgNiVtWHs0c06DCMAIJy4M8Lyefs_qPtJOJTOM6_pK6PhV.DwCqAlYCCy8f7wlaqiZcn30k999UUu0y8VGUk5b4lXkyxczHh65zS778wP5Ua4ey_YpTTFRi8LssPfKyz7UaRaf3txqzx1384MMJtflJw2FIPi44YZgnOp_LgktH6G.vGiW_xTseECAYakdsl2.CphQ0qiOzC3rcOkqLa3jwjrbaYny9GTAe3dyU.PACbbky8uDkeKWruO4TIDIGO.7asDSfww9I0bK8phzGGQjoGzjusuokQYY8uVT5FxlSpJxFCIA8l7uLQVXqAAnGM_Mxkc_Crrj7le76onmOpJuHIgp4hk0H8f9NBHOlw2lXIedXtNqH65cxb3QZQtgjVUVcsxfqkzil_UPh_suWL6c6t_Idb1kA1bqHS9zJoUzKDh9Xuqy0DuMtvp9CzRvqGNSXEb1IqW1SeLCXmhB98m3AYqUEztUr2R6fZ4UwF4kHurouxwbh3xhAl08sXBmtso2LtQn_AZLPL.HgbYUHgss2WYTSFzUNmIfcTWKEe4QFDz2JNgja.xwrzioUrBnMAGi_gQuikHX8kwdpAqxP5Ov4ea9UuyxF18SPZK3v5AhFlvxkIqKor8l_9.I2_CZEygJCPkexi3m1CZgj7j4C0SO0XGljAuS3._udkFyKUaAyNJ6Sx1.XKCS32wp2mhwpif.K1nfrp7PmFjTV_wRrqP3zQ6q8ykJ.GReIU_L6omzF9SFaqWQhGupS_BdnA.2NRZ4rYMZ45lAObGLBccr5S0gfxqoTUg6b0SBBufPw6CrVGDO3Sy4BjlFOEyESCBHsGRa1uz87lEGa0QKxl1aFjZPSFntkFoH8DsixeHAMzb1PZohlmVxCGGI6o8vqkGM548VmpYY0_lh4twYqenrFPpkHBD6jJM5yn7VfrGy.oV4Tg6CDQClWTTXGBrzZipp1qw8A1Ze8THnjn7AnZUt2CQRSwjCzEoKmCZv2JITzUw0flMXr6LgsYaae6vyszx8WBf0Uwt_mfC2FDePCm36l5ProUgbg_ilk_ZhKg4F0PkHEctBzdV5kV4hceZbHAL5VzvkVS1elB720DuGuDThW7kiDkE6.xH1DmoA2lA8K3.q1PY3RCqXX3WSgUyqfILioLeuKMsAcZmtvY.QuzHrzGU0NFrvdQukcmIBZ0mJr8Da1RhvLo50Xicj4fOLDvIMwUA3IwVoaE2gR4JN5rPoyU3EYaxieXVVzLJxTJbTwRYPRLmI.5_tszFjHySjcld9JMYcFbXGgX2VdkC2ubwu.svMcG0mVDH2NufqMvshVlg9M1.wRxMH26T.Ibz5kNWdR_Vp1g_zwCrVSkqcuo.XAQEN._KA8M7omGCfD5QUV0Bh8FoQ.szZIqlOdFiK6C9uWDf2mtrG7msVKhs4jXoGarOwmunapxcG9RnEyJVnm87n5QMAI9o_VHj3RN7Ut5TTd9guwcRISSQBjPUwKIbjU9J3E7NkcKZu04uLxc8z0WwEH1xqSWucoim5WSSqiLYJCPXE1VBCYkIb3zvRP6bG4SUIF2zVvEJnn.RhTsEbW5IVtZcHB.1Z66XPk14Ji3XBThceElGwkShUGckIpmNveQNIprS1.LH3CiZYrE",mdrd: "3f_HBARTyhggCzVgCBRfeUlmroL3uIt9dZ_BxdRCdBs-1739783985-1.2.1.1-ocjsVzpQSoJJbqjfJ.8P8inVrkmUnJw_Xbyyj2qqHCukCtomPMUlgCpV.lM_mF44oinsZ7QvO2zLLP2V3v4WZshSfz5CGrYJDXdTySJXQClob9InblQkAfHtkFOz5.ZQb73kkDxL9f2Oy.RTsNw0Ky7eq6SgvxCeqf.TDSLjMF63Tjih2bkY_BwyHX6V.5zS3CpOsAP6N29HjLObPcda3Bcb.FJ8e75Hc3Of3Azkdy4g9qJK6d2SiyIqY3EAkzWrz4ikaQCOLJNQal7CkHAoYprsXI.P4rgNc4EYRUpguJT.Y6QfSqZJYRJcpfp6btrKk_I2kWn6YYCXbizopDoPQypPbKiLN9..W0Y0IStH0w9JX9lpyFlVws41DKzKTvBOZE4jd3g8_l2hqCo3EO7NbL2gjioMhwk6TNb.6Mv5NfjQ1ed9kj6wNIKoFpRnUAdyZFGLFbtsgWvlzY2v9yD78NnXB6N8STRkpoyFE8zn9Z0C._o.sdcuz4ztrFT5RYiD6rDt7NyQjRh21kvtgVF839oOcm5Vm5AJk.Vfk72CX6X86T8o9zO2CnEIg55yYUdZsAOUaYlxnVAUqMzrrUb_GkrxyzShbDqcqOnuCwN7MHtLHsElc1oRHNqFQ1cYbzQK_muAqJ1LanHBmd.FjOsxn.MkPWvZyO8g0OvFTrGIcnpxTrbzVVYREfL2aiR1UzLn3DtJKiRQNp1Keso3c5WuFgTKAvZZ4v9_8.NmeRieuwDGgUgSOpc5ClgfPhf1b8MbirXAn1VNz30wn3mrNtGzP41OmnW36ACepHRqP9uoYr_ByMEoyMuBDUs0Z9gBy6.IcQm33zwjGGOiXOzYm6LMgF_K76XHlxlcxR4Fez4eEe66kIEXdYWNBErr9zuODuo1je6tqu9BBOWRjrIpmJS5hGUeHntyEoX0gWRFCSJ2hBautecxL9wiRU59HY2VfpDzqBMWwM9Lw.bYFLAXNcYNhYmyrlBrJjNLgTsbFYBS7CzlElxRmvIVi2GxnKH3FN1YtVX_H8XwPqXiEXvEW28hjtbWuCrPMyahJjB8iwvIDVDGHokOIC4jXc0A35tNaK7pG8m0nCFMKkN2CUaafzsweKtLQiXaUsXMWis4HorYVao.2g2MuVER68ItpEW73._OVAb0vcW3k0O.C3GaPkMr5wXAqPcWkuvoIqE6sucYfFFdhAMWhZXL1vnPyaJ8OfvBgn5rTq0006e3zFOw9t7I5w73VgNfMZ5Iu6o5s5XO1mfNqBaq7pIQISgnQ.xvPwrv1AEqXiTAm0Nj7Nokaz7nXJGO5tZcE3neN7eyBfCD6riCnK35TZKhmP61b4G1_9DEQSrUoepZCMifx_MqNfrlSFUQJelN6OMsnAhB.BX83GiiUaYvB70zRTKU9JacGp23eYgkWH4s1ybOZJB1AyeMIWdtWGnDTil5z0WJR9ssO6gAZt0yujMtERpmTxass82DArNt5HWuQ.DOx7ehdwpMKdN05nYaqPzjrKbLXvJG8awX01klwyE1FAaY8mOf5GdkgNbPMhJaQRxDiauXddaX6Y4c0I2IhfH6E6lLdIjXd5S1D8y3uKmzu0Ri7EWHrRVnsnzPpkdbFnb4qec38emQOBBJ9DdhovRoEczDGVB_N1YVq4c3ILFbUDQT1RHdN9tWIYw22vAS3BDGli28.ZrDkShkw0Kft6UCXRc6jQEe0nE92pZi5YZaWRXLvxRK5R2BetFDtrDPMCxJvNG7f5WZ3lbsCkWwTJaiN1sXwe5VsXVFpX8Lsea1VGqie7IgmOrtH2rr8P3yk8PFuXShr2bJu1MkQangjXFXuO9stxatyVy6oSEB_WKAnntvdQM4clRFMfeVQG1gAyuTyjB.j2d8MuLqxw1uPeUcYJsEFu5bNUqL3modPLN5NOGPoETnpsI6VLAqI2k0l8rld04ev7AslQ0Sj1f58ioh0riXfFG8jfw.4YTfLH7wSPGnhUDyqTNrw.dy63nlw.38dtJdezOTlw"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9134b2982c6e8bc8';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, "\/6274\/harvard?__cf_chl_rt_tk=5bzjwQWDIb1qirSR8QbPUW_QONSGpsNA02UydQeieqw-1739783985-1.0.1.1-dcbT.n6nfRAy_XlnBaauHFZVDvfwSl7Gir8FGEvOnlg" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>