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="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: '9135d748dcb340aa',cH: 'NEVNqjo3OLprniMIjY634Vye1dB2dDwqmMizRth85MQ-1739795974-1.2.1.1-RYAD0HAtQQD8qo5QrTR2dD5AZgG_ygPbAg7ip3W5nPpo4JaxeaVT1uLJGJ3rzvth',cUPMDTk: "\/14864\/iso690?__cf_chl_tk=HOphuZv5EPUJaWxKg17npVcAbDPMlpWtAohltoK.gjg-1739795974-1.0.1.1-yk96EtSaF67lj.ZLcczU40u_j2TA6fBrQLr2UafkrPY",cFPWv: 'b',cITimeS: '1739795974',cTTimeMs: '1000',cMTimeMs: '120000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/14864\/iso690?__cf_chl_f_tk=HOphuZv5EPUJaWxKg17npVcAbDPMlpWtAohltoK.gjg-1739795974-1.0.1.1-yk96EtSaF67lj.ZLcczU40u_j2TA6fBrQLr2UafkrPY",md: "j9YHFcdHSIFvT3OwPkWeVxQe2hqEkolbMVjbK8kCpuI-1739795974-1.2.1.1-MrFf.1gWB5U6G.g39zRT49mPnmgGA4su9YqXAixMw0__dxPMrYizxwdwSrGQnF0X8RMo.GAQ39W7OXZuHHFEkjq49II5RrTlVFmyDkisS3ejyd2wHtoRlhTYc7dWE9fEpih8GgoU7QHgWt2yCh0cMYulyIx7nslnwV8OL87YCFp9w1W0sgrRvqjsNlju2NPiVJjiqVSyhGOCrDVpn0ugVZUyZRW2w8ZtVnz620br_fWj.tUpW8ilrT0ds.LDJbHbuZZK5vzNDf1bGxRwNYqEXzWQkKwU70kPGS__81rMuY1V0qz5Ut6qCDisZv7WJ8a6_3V0WW.Be8Rex6ArMESmNIlEkAtscYe1yl2zErULiom5T3xCzCaN81Juql0ReEFKJFYqis6hBudi.sqyDZWmiDTNKgGa8iEMikiRV0UNbky9exHhvL5RkjhN3cEoigDdG4F5XPDOBKzO6svFGdxooBQgQ374qtYJuOSzlRZ3tSxrCLkRu8Vt0eAMQwKeEyUfWwq0mUw5t16k3bxaK4ZJGnOTCZ5ZIEtwBtVUaw_3uFYUI2PVQsFRteOvU1u0GoyLOtyA1a.Ym3f0RvhD6I1QGSTWFvIEzBXP4zF9ehPsQPqT1mZU.W.cFf1n60.5k1Lzgqo8eFLZ54p3rqyFvMVjShipbQssYjEZWzGh_5P4dZ5kEuFeDL8V2qsjf6guJn52hGyuRy72TbzkiO9A.Nq_Z7ObU8k6.kWAZySBAOeR_rWlI.3_tV4Wc_IU7IxfWj8tl8n8LR7GM1QoPYs6e0uMqnsV0v764MPjo4YK3afiA8l3NBiSrckP2dfLHcu7_4ABXMtBCT22MLz296JxWYZTgKvu3.p8PzGedfWQYgDYZLB523XgZvnf9lNdie7l1Kg7NAsCZfYsZ2h9tHqL6QVqI9lO1lzy.4YYTBx7yPPOSFUn1U6sQWjWdy0WbrfZMoDnA7H4xILfs3r1SBd1rpIOawe9tkSkZTenCyZI3yMY2arx8.8mj3bvD11sMVvdK9nk5Fwnracf0za3LlfftikvnyDb9a9XcSI6sRehV9bI0_DQCpNADpfxvPSzfiuEB0.THMY0r5__Asgqi4XyDg2WcyEaD5ykdzWXp5m.qe0SR_L.5f0bYZhrs2ZS05gxSQBvhZijkZ6nDmE8RAvHQExWS7J898SuVW43XroyZ2eFl.x2wD4DMgC6wvtdoi_ACFecX850ij7.575AUObIH716Kdgaspjfo3QO16KA7OoCoFfoMLIjYBgtfdtvprJe6CcNuuMZgO80wj8bVMOsLt70Eid1qtmzFRlD79Z74cAYhNKqPWfP.HadZP1kfqOD9jqoVRxhwlM05Ue6wUWT7LRbkCvlzVd4LXynKHkOx2WM.I9NSSvUd5q2xvlPtrOyplsJmNeG.j0h5irYp2f1PkzAT203nAc5TVRX6ex0TEz06vuksyjXpuyZS7P_0tp9nwr4GveMWl1x4WK14vxXBYF2ElbxaL0yxW07UiEeCZAKSGn9Y7JoaTzVsTFvK3B9HaDnsdrh87WJqDRqzrq5a9P.1OMCyNAJKbxselqV8GDDjVUWOSTHTtrpyd6t7X6AInr8yskjReR3bZI3vbXzG.raIZY5zi12CPSf0J4KOZuW8OD9zZD5q2g.cAdN8mBJBTKGPVOTNR1c1.H58JS3ySuZMU0EmRggOMAbKNm4vQ5EDZK4cz2URvBP8JEHHbx6cM1DS2_d_9DBHL90Tw_Z2Q3bfo6ChzvqZ_xIzgGc9dayoVprmrMTTCMPpRlcbJ.kjzcduP8._9doL.VYQpu0fiW5KLRGqRCCYxyzlptWvonp26gQi288LiacgaV4eZ8_1OhBNRx6xnf5sJaLQ5vBgsPfi2sWFR2oXcpDS7LGTJuur6Q",mdrd: "mu4hOmhVXm1BiJKnsigXgg8rwR.1UYcJ3IvdRJaZAJw-1739795974-1.2.1.1-SxM5l7p3mzyMwOi6iM0GSGpkfQNu_n7rhJUgVBBJL8EZOJ2S40jWkDkXLEBrlQpAuzf3ZxeRKMWjHyV7__xRg2fImCixeSMuc6YiZezbeiA2aCPe6hDYEfu4qbm39vC5c75MU4z9UEGHlPI_uU5LElvl4YgbYbi3Bsjhk0sKMYV10T5.fSxeAdPsKV_jU5SJ3A4a.sOOJARMA13Hfxh6h1DoldteVVWzX7PxykUaq8hwTVDu.N0zIEWSxRmefIrg9OcU4kqwa75Y3g.lI67IVwaAGCShpGzUDlWosZ.RFcG3_uW7ZtHDUwR0kPxJXUHisHZAniOxXhVMnHqr_9bbf_ah25hzD7nvx0PrwGpqOTov0MsgDRELVE1mWQu3jx3wYzGUhTZs.vK_oulQU2ZLbaxODQHPLe0unrGpceUkS_RLYSPQAQuxvCQ3XlegxyZl4JoFYpvXuPB6TUv9Ipj800ErjVafusMsEPw4i3BAqS7PP3D2imC1oalKrSElGhcLwW.bE.6OFZkQTtCS8EJpu5jMQ0uranf49Fr91_fyOy.wm3avLX8tynzg5j0O17MeFBwNRXNZ3QGcBbTS1VwYMURB5MpHWloFFYWQcgPT6cSpiyxMs.tBJ5gS9vE7ZZnegirjkw4kHlgtWBR3xP1eq1shXpI4SYQEAAklTJc91lA_DKtMUlmKRV_dZT18F1lTFVKH1mmLmUxsvrAD02YHSN7saOPMORwiL.7IzFgv8f_TgfHHG042gAlUaGyAMWSk0S2QMtKXwpHua3cjwfmbAowDwDyqnjGiW6gp7tgaHcMOrGyIPPQHV2Oz8PHjsI66ltbVjiV2Txhie4d7kCvIISJ7yiuwVnBowNffNFafsJ8OUHLyGeivEAT7gyhXjad.bpFDxl8oO1R.16JvOxBowdCbe.tvO22IiMupHZOUMp38oVGZPrPNXPsDzlqiMPsjoLPds_Zbpalo11cyLahsOCDvEvwJbBcP3Q8WqZI6SULqjNbYYlal06T0lGrJjtJTSp0mlHU4KWNHswPyotMDi43xjjjjHN7RXb_cSMr3QW7Ezt0mAizllswtrHbTK1FHuHZ1RKmaF4c4h.b3whcPX8WIAsC8Ka1mm55f9qfyYa9WmTVDksxRmXjNU1uuw48.fIOMzXqnOi58mOjgeJXoKL7kza5AMOnH7tt.CR1_NrB4A2uQnWXgTd2.XGtpzzoQqqnOJjI_wsGBeerch83qGpvZeeNrw4g0lPPVGMumPRcqTQmpfxYoVtQ1dv0X0o4cvNYZc7OKSIm8O6O_tS0UIagbpPgWjIZlux9wpUBNdQe7V.XzMVxjqa0uK_6k4OusaFXR_bozUPF4ZbRT7S7OvjiTJaWL4bi4njZDlwIpzYAnqknEZ2f17Z4dFPZ9f2fmcWhk7RpwS7F2JZ7ks2YhV0CTMzTP.w23vDeuiGfiQXMUG9w1XKJ9xqyCtbTEaZvtDDwd3FrExv28HU5XutfJgNxu85CeNku1cPDcM0mGy33xoZACqFiJCTrSgFP8XOSkUW2AXv.DMUakDGnl_YyDJxBp8yfrmDOzyhTyM6iDVjc85dIs6J2A4iXHOEBJ8EwWOAIMXapw_PiEMgivhIsJVzw91BEI0bxvIDG5Dexy_sbkZOYGRNH7I7D3sTWBCH53OCN1dI_ImU0QtL8J6KXEm0A1WSIR82Kqoek.HxqWPjNHOjVNXlpyLWTQGoh_E3FYKpVpnDhgyFMEzTVVV46Wmg1yNSnETrUgP6DEWm0QzBdG0uNw3vgx8yiclJpVDjg0Cv9rpEUFoGSr.iNkcMPH6JmtMIr2rKHyROBDBlPo3CcvfcBzvlfwp8mCjorRGtAhhGS2Z3L2PGFnvsbUfhZdURECUa1Jg7sD8hPJv54r4lPW.vaMLeVboxbA7jEf64yskKAGKXChXIsXvk.3bSTDyqpLGWHAa7rgXqP86z8mYTEqEA0arRBPMrfPaGBTuUbf"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9135d748dcb340aa';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, "\/14864\/iso690?__cf_chl_rt_tk=HOphuZv5EPUJaWxKg17npVcAbDPMlpWtAohltoK.gjg-1739795974-1.0.1.1-yk96EtSaF67lj.ZLcczU40u_j2TA6fBrQLr2UafkrPY" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>