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: '913660833807fe0b',cH: 'OnHbkKTmpISyboOrT1T6_o7AyRMQszXi.A3ekmwzqFk-1739801595-1.2.1.1-lJJcvhskPjBSAAliQyREaiIkL5l1i5D3Sovf5ACsLCBHeMqQz3w0cK4OtuT3A5Hl',cUPMDTk: "\/9999577\/harvard?__cf_chl_tk=xPgBbugFnAk9fnBuw8LKm8IhP834YdM37kvnKoP6msw-1739801595-1.0.1.1-AS4XbNjfKSf647OtZ566Ne_dzPGMYBkoOwQCeT0kvu4",cFPWv: 'g',cITimeS: '1739801595',cTTimeMs: '1000',cMTimeMs: '120000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/9999577\/harvard?__cf_chl_f_tk=xPgBbugFnAk9fnBuw8LKm8IhP834YdM37kvnKoP6msw-1739801595-1.0.1.1-AS4XbNjfKSf647OtZ566Ne_dzPGMYBkoOwQCeT0kvu4",md: "BJtSnScEhAWWH.o2Ug1JHrMxJ5gbIDrgWg9yQa_7gNw-1739801595-1.2.1.1-Su0GjUsiYAT3.LhCEbPMPXm4JWIiHV9.1Le7u3mcU9Ee.0iCZTZRNrx3urkZF4NSpoZoFTLdb_ZKooDQ5YqCIfLb1_L9uJvUBgBmARO9ivCdZh6Cz1XTG0KIZCvclxiLwH.EBCCGsdadMVe0gd0EJa4jvVE6jHR_aXdEbd3nUTuQPQSk11r7lC90azQddNNjLL9Jxt.mynB1LEIJ15pbagrtjjOiviunfUUsSdpYbR0IwyXH8mUDvVdEWu6p46jR0ZcNbRzV21V9drQHj4KmsRKmB3fZtZyqo.oclxzgnj8Cis2ch52EmoWCsqb97QU_IWONESVWvHfPW4PPRnjetnIlg2e4bmzWOgRi8fupWzZDQWu0XNoMXBxG.0c46ROZSjx9ZQDThhPkcbAaLz5QoU7V3PHd58uXjG892F3vgeUAVwQZ8ON0e1j8.twDX5iS4QQZ_1dLDzYSMdSn8RIJqMkeJc1.YHRwdsq07wwpI_rNM76YqN0B.aw3d7XbVaGyPxFV9REWuGtzyrD8yuQyYjSadEZkunreqC37p2aY2.NniXFCfiCZc43g45znZhteVcE31zCNGW4Q0K.jNkpwuERJwwQrxZJPaUICEViPTmEqL3ighW9ZCfdyF1pe.1iSsHpKcSiBAPFNgmKkJXiXyOQ0gCsWk0twMGtURZ29s3B0AQvgp5bHMAt9C_XNmfv2tiLveYopNx1hNe06aw2QNbwq1d4xePwSGFyTY84qOSy_eggxpRvCe4n.lYcfp5mzdZiq01ZBj3wdJMMPWlfZf1LZAF0W29xbvNkx2dmnnEyRhYj6XeaXanhStspdKjzhfFwfZAembUspObkjYGxbKDkC0nKJFCri1bozSaz8yjGoUK_OzHiY8Zn7c_hh1hutRkcBi0Vj8HwS18XbRwIJAkto3uX5xXgnFWZRaBj0ebW8ojx8FKW8QNMSjPaUnibQNsLwqGGxeTEQRfdLWOKI23Soc_vmbFb3T9gl0HWGwIseko3sJ6fRI204J1rU95BQ2bN8IlGWFk9CNe9hjXhXjz49_0BGcPsxsFUYuL5a7S2Nc2cwgEXCtdudjbNCpuJlLGs3TkvnKtPcuz4XWMJDizbzCiXLqvtUwLLU9LW.UKjodijQ53fKuPc8UjqNBpsBILLLGQPsHtJjMPdCtHgBrPAF5Pqs9O4QnJUwLwJIdtjI132ayGa9nfx2e6Ntpna8vKJg6JnUsjIax5t8KDaiWaCB0EBU52MSXBOixnMuPOdluwl4jrPErmRq6vaiSroyPWOtM7MFWw.vQgNWmTLgehfAhKTVU1tlxH728k5jJAwr0tn93BzBc1oDYGyaj66QnYtAREMgwXzwKVWDZ3wfISBrWB_on9n3hC_de_3LeMyqNpnEWCq94iYFNFlCdlgiOUCsGgOaazJo6i_OxOUOAahm8yjVDrrX5NiYOcmAm_RssC4QsJe91QI4oeSXFwN3uoa28Xdmi42HB7w7402PNWjzqCidlIYx8R48NM4u2oJOZb6JKcE66jNakQTs48PYGGnWKgTApJkE55.XZOFZ3L4NqNUUqbQ1DonUVdsAqTI1Mw2khM944_UFsUARLDSz2QKn5poGtoU7nWtQSgsKWDTApA.P7j13fcUm9ZNuYYHZCKuhD9H_B7zwcoi3KYqxwPsrQAZn9Xc7hzjB438uLAE68j58YIRRmNi5A8laiodp9eztLSCD136hFkXrOdTXRBddMYgyaTlGj1pY7jrLuNlrfN8pcVAc0S1sW9o1r1nyv.JqfoH0zP6820LVi5UBWX9E_aQmIS5t9OYgbBIraaTW2zhmvBoK4kCoYlexK1dniCou3rac2CJd8lLRQgjyb3GVj4lg_LyZ4UtDxiN0Kt3U.3f7BSDu3H9Ks.67cus",mdrd: "uCB66AqIgICSESPqyz4Yu6jClRhak6JW7g8EU2HSmTw-1739801595-1.2.1.1-Jg2.F0mDWbVhzZ8fVAJq0lgBMZDQmAFPcq3v9fbRtY8FbExlWS4PxvXfGWi924RhGwVOQVvnIQJDgxgPPqCgoUnnlRunjkF_q_cK5iygijPwX39SYJER06Ske0GpsVFoMmR1mxIFTMcRPoTsIxZ8lFcdBDUSHUPQEpqGiv27KSH97IiNFUvUI9cBIiyrtFq.BudS7pc6MvHpu8Jo9rXGhlul_j051ZCF4usmZPuANEhVBfBzj18aTzgsoxJQAEqe6SIp0FWdJOlVW2auX8VLFymQMwTjNbP.YhgHTJ3EEM0uoIg1dbyIHwOQrSJDHPGr5p.ae4FCFej1XvL8C_W_QVVNTmnsGk3l4CMTCguF42yh0_E7xObTPK4kYFwq9U2BZSLElwOblCnwkswcj0fgfVeKql53nLDtsDdpz9UhMKsH_ylAzuoyJ4b4vVd6q8_a0rH5B_HU2ppnRn42xUcLfwm8ZzJEc.Cczkt313mZ9nxS2nqKyZQHJoXbvoXtNmVOrb2D5LBD8cz36ZGLe9bYgJCjw8zcn8PPpXaRnSthQPf2ZcJCZqz20jhRx05Uizo_oqEW1mo6apCuTWhvbIuceN5sThXHvIqoabyvazY41KqSOA5pCPkjbu3vrxeyW27YpKA30WSHZR_1YPt617Kbkmi3pRoKmslVqjMESYKPPR5ZWMeZRI8hxIbUUDq3jN5cZI8ZvoLTLq5NU_dmjdFrCf5vqCIqjPE3_6p1PASvjN7JiFt.KGoSNbP0M9Wmyqi8SQblD5FZcyOp1Z3OTC.nEuvE9REkAhR28TeujnsKuFoiq4Iw5NMIJRTy6bYPH4Qnd28tm_QJLHE.Vvu25cLBjxhUNJEFifdfIacpyoo0v8hXpH1pArdxLY_MUQPyeh2c4KWmpPTNuly_TY8Tz7ExrwB4vtGNQd5Q7srvUnoGxs4DwpKUBk5BIy3YY09BaGpBY6TLjO69MuyqnkC3Rj5UqDs0GiKWwNTzlmfs3krPTvCnTCdmiKm96MdmxhoaZoPoDe5xslEXqwH2PHqnAdezb5CRsPaaKfErDGnQKZbyzOzXl4p4aP3qVJAOzJdRkBkgM3YeiQ.jFfgJJHVJTtA6Hm3nyHo9isjWdu6Zdxuqkbv0F5k8VdwWuAEkcfukSJ9IoVCTfEKccyfEv6UoRgkXVzIsk_AxrAwQUlHMpZXSn7oUryyx8QKSc4hr7E6i2RRYozqxwo8TqeZx8NhGwBNVPL0coGIjOUNbTV.w74boYDOP07Z0gGhTLnGd0JT2YraxzJMZeYQqBe3ZxzGxUjtolRdUlp8XbgsT4056L_XgERSBUldqe29ClnY5IzNGk4wkJwmKC.NCbbzQ9.q63EtzntkmogzAlWmP7sJH6OibsaVo3xmtzV1dzf7vXUD81itPmVSUBA7gfZxrtZDr33BqmdV9jx9PznSynr0nD9nmFGW7veFhNM9qc2O5TXLPmBAbAaTkguY4JCBUQXYJ.MYkPHzF_fqASZjRHTPrCGq.oqGcW3grrYHHc.ffUHYEcyhcKhMeM7AE3O_Sx7AsLprLFYqGBEJCLLptiiY9XpcNMipR5FqT618NctORr_RCDW8xOHSwwTCs7Jw.F.eqJLic9jfZI8gpCz9xnFfZZlc0OyYwwLEtKRJW.W.fivbkxgghHLmMhI84ccADETDrFg7rpRnBDLBAlipkndikkNtIX9zGGYhJoncl40tNOB92Q2GgTVPKKKG39D7rGkHczABggRvMixF_pYU0GsvqaSJe0q.4f.62fXcDK6hR2TUWYVvmyObZhfMBhYQRXJdC9kjoXQ4O0dY4dVLgvm1vvaTu8.TkydM8X3CpkLUh21GVsV4fM14g_VAWuSffIi3MLV6hEIOEwiGkqZ9ZuOcbsxaxCw_Y_IeERLiMyeT1S7jgrsqzP1XGEAd4l1Vua5XlRshiKXU6S3vJ6ADpm6_Od9YcAvRIV4Cpgj9AgqDM79quSVj9"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=913660833807fe0b';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, "\/9999577\/harvard?__cf_chl_rt_tk=xPgBbugFnAk9fnBuw8LKm8IhP834YdM37kvnKoP6msw-1739801595-1.0.1.1-AS4XbNjfKSf647OtZ566Ne_dzPGMYBkoOwQCeT0kvu4" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>