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: '91353fcebc37f882',cH: 'vFrOKW5iCt7NFMD2J.v6bMOhQ1ar0K3O_lh3FvkM4xM-1739789770-1.2.1.1-gyYLn2.p4selw9zDo6P7Mf08wwWRJbUBYi_0l3IU.FsZk_E5JZ5bqePEQHbNVgya',cUPMDTk: "\/6967\/mla?__cf_chl_tk=Uw80MS_0lALEXZ1kLc23vqypR80i5_ZLCLqztO_5jJU-1739789770-1.0.1.1-kDGOKCi07G3V6EkVR1qxcms63OdT258vYVltnrWTDag",cFPWv: 'b',cITimeS: '1739789770',cTTimeMs: '1000',cMTimeMs: '120000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/6967\/mla?__cf_chl_f_tk=Uw80MS_0lALEXZ1kLc23vqypR80i5_ZLCLqztO_5jJU-1739789770-1.0.1.1-kDGOKCi07G3V6EkVR1qxcms63OdT258vYVltnrWTDag",md: "XkPoxVcLpQehoGvvnLgBjfZZ11oO6578GhMGcRaHCdA-1739789770-1.2.1.1-5LylIhos6zRvI_JJPoMB0SSy0I9wqlDu_NulCP7d6toACS0cughBaIg0nVMW1COx4iNrxRYiZeLvBCqQI_t6HHOtdmWbwCuPUxjg56uehNRfsLjJjbYohV8rNbFErVZx6Nc_UroQyoqOOcpsAYSymlseggo2O0FIf82MhGrpZI6Jzaj.ksD5IwCt9Sp_cX.eq8swpjCjq1ESItSEzWCh_0VHWkPJ_WqmJFDXIAQQ2p9RrbdsTKgXbnj7iAo7e1a_Y.7B3ys5kDl7JnwIy7u6QzzBnxhL5dtCqwmuxoQBmti4mfGngLBp4TcK9AwJNc.tSceypr9HDGasINn20kmBBnMR.1pLO1dMyxNHkl6wp06yKSC.BMhP3uX7r0AdmTRQd6pcV_69uEa4D.dZpCy71bEpixG4i4r230o6OQXAlSUUdtFW5moc_u1fxT0AVbEEh_GdyPMda4SZVkhch6cKKaCBAQbC2EKm0C1uAJiBneQNpXZqhW9QUanDeIGo3r8jcXTZqxD_r3x5uK5GjsYAIm3tn5h2BBAr6FBPU5yewtlMbpfCsB_Ncz2CxX1hjjEOMdWFbEmSEdWwM7eX_XzVlBNoJJP1yTJarkGoIrITrc.87gxn_I9bIceek9pMabcICOV06ccl9kO836b1Xl1ykKppUjv.f6s2tYO.YuTm7XXUGSSyp3JRHRgqAQkfp3OPeqYsK54HV8rD.fLqYtlOUulTSPhUPIvtqrHZoK6INvmAjOjyhYxYBerJf47vH0SRMNuEj0rTArsOSM.TDkpO9A2O827ySVUskA05W_EJSd9Nl44V0R.rqCNzXrsUETnvgNVbvWibbXUBxt6lVW5cvmhOB96j.bahGGO1VULsvH8BfiXqmgXv776yP3vn3Hu6M07xapEKAl65w6UKbWXs1F6WgVNucnB5uEArBejkJI2xKCQrAh5SWRzB0MMOmDrFyr9XRiKYvMlqkM8MJXTVkiIo8d5PTFNtDbjIgcwitVU9aYUfqE0jw0H5FHyWFA2xYtGFyk2sKGyT03Mm5Yfd51p7g.NeXvADJkUWR40ndMSO.sHQV_PNBkeh7xx.q9jmFKMv0q88NatlXRBfQpqotcsUpliG9Fa8vwDxqtbmeS4tqR_qrMjRYlKKYSppuJ7EbI0zn4ILrlT.oMhKxAeuyaSoD_LmGsWKzDMSNB3Nbej2HrgBiIavdtygchZqw0uBEHNWFecRZ52j7xXiEeRsy2x8aNCx0gGJRFbo.TzRABU6pS8ve1N8Fbav0ACaeM5tSnccTTtAHGracb3P8HTANg.UoerUof_1yb_URg4D9xOjH.dhw13HfsemXo2.Wt5lc_koVd6iKEUKKY0yTAvpWFhNdTnk.xswmvR6xw0l4qalbKwnmqomEmqhkBU3wSW1kJBZmNDt6XJWku1u3irM0cpgWD_YysQrXxgw9cURkqMgiYuH.TjumSPAKey8Zbjtr5jn1niBh6oMK_biQQ64g5SPL.kLmjPANEZpKH8aj80b9.zk_c1S5phZcLdGXYxLSByP0KUM7u1n9h2kX363jRJ.NG32Wxh5VG6vb9LkCq8EhYorNDXC55cv22PJQE2l.CxJZFbvJzukBR5R9TZjZHeZsYvOU1VonYb5lw62tJoc865O7rtqIQ7BgcNi9VEm.CErRy1XU4s1..kUWAjTgU_GEizgd7UY15XDGhENv7qlafDNMngFmbkCqExJKl1gQcU8J2chIMWyLRRT59Ng0m84xuGLJkqNkQxGBLJDdwg7A6oVMIY2T7i9K9vuhCNfV.n9hJ3uKXUgx6FieeAGegRmw3BS9urxN7f0bNWzoYpGcm0qtLLHj3HdFZItVutrwiMIYcCZhIYix5Si9DrLzQ",mdrd: "925eSZZM5z7NsDRs9ORyB0yLJ6iHPRbAg8t.DZNZ370-1739789770-1.2.1.1-O3RB5b51LIT1V6TvMeeR6I5D8_y03gJn4JcKP_no1NREeq_9Rct_I56Qwuvx8RvN9wXgN6rJ9gGGc2cRpAOXVIOs2EfutZUcUpUrX9fKttOvmWkoUXHmRKG_QoH4NFy3NAQHfWo9ILqVICD4BEgzXh87KumPytspdYCP9K7cpXsHDQG2ibRNtuqfWbE8qvXFYYXQn7Ai7GyS4JP6yMJeDvHUkd93Ofini6HCD4Kr9W3Cfa5GMbjq3dQcJjHDvC4hAgiXRMcYi.yk6DNsqxeG8J0ZobD4WtAOZsoGZo6hcTFbB0LNoL20PnrkT6lEmCo5Y4Z3K41kHSsRnQsbRuhSEYBlWyRzLGXrl64VkH6c9blNRrPRvgCrVsJi1JYIE0cY69GEuEcuceipwIkpw2KHiE9MBnEgOULmr7Vex58p_DVgBtIjw55DbtGCq05dnLAQrNVLKHBglWyKVszHzHQHX59EJ.yTGA.d.t04FKlXqVzSlv4oFviW2GPzH1PCz5VG2nRnXGNZJ9_MDCRAqKupYpKChinjqSqoHpfGi4rKT6c3mtgzZIg.OzPz3EqpwmtNtATH_o0tAcuRaDuAERUAvkXG30OkyiP8T5DndTaXv7KgnMyZiQDhYsmQx7jwyteriNF3fmsFiYMONq9nFaF6xkleVIdNwg7zF3kMXdeej1wPA6R0xXGweRcPgZiBZYhi2z53dfkIkJn5rZ6iDqm0Kcut8fTFTQy5sh1w4Rv4ib8_gX.tjtvBLvgu8_B5fbHNWEf8yR41xqqj9kfeauGrwriLCT4qYvi58vG6_YTSWE1rdqm7bsLmgyRVaFN0R2bb7jV.wr4vBqHfAQJm9MEo5AyXCjH.3Kh6ALZDnZstG6_9K1qD_AMcNNpIvihRUUGt6_uqtBs.ABHuEWh2qUnjaJBJMw7JYxxm1n8Yjk.YxJGZ7LMxY1RlcPZyyOLAf5iTCQiKKxLFJaxbnVFnFfKADTlv62rl8Q8jUSnjqL6iWBnBm28h9TNVMwjDiSjOA4WOYutOD8ktb5LgTjbU4DliJKJX9wy.okfdznYMC0jOjBeQFUjh4C7Q4l1P7vH.4q.CZNlzgK1aakWd2itJNdM2LAVeimQVVvcwHROFrYaZ0bwcSaaOGk7QqFbJkcgI8FttsRW4V4JftLXq1ykOQA9Vo2eOqi095xiqnY66xtDSJj2OtDStLDJmj1IvuTWXOpzg7LUBGNP6qe1p8UoFLgOOuHFXoVnqg48DkaZcywjvm3NLaZK7IMNXVg9B0rsUskFaHVQ.djvdyWnE7JEXpS6HpewJZaTRidHF5a1YfpQ7TppUNzFmNYXFqR5ljfrp48n3M3h06n593JO92_XyaKYZSkTwHvpPbHbVKFgfTNAO8wX3CEYjhaHLml3oI7uN8WyblvzSkzEv7dmZoE2w15x9bL9s.kT8zMXxxpL4paJffxhG0UHoLgocMPdbcP_.QY6wwLxL361yxcbcQpR9r0hx8Qfx_iovWPFAPGhjY0qMDW3GtZHSk_e73Cd.od4DPzfjmdHs9_.z0WyOw7GWbZTVn_WMWhuV5hN74A0_P_tpiCGwU0udAaaJvaozoY20NPbkMICCjo5ohwkxHkTePn3zcQuM8k0cm0XuOA64JAdosp84XHbuJQGoI6I3Rh5l6jHvjiPDdE7wfdw.buE0F6UvfGu2h_1LUFOKDiRzWlrEZAcHUTVeTAnzYH3UwV1W4wySZ0PwR7J_Jx.UO1Hs8y2juyw8kAoX3vuMOElII3JJAoz.814ursd5eXDc9P2sat51elFX_7_3Ub1ftCElKuu.IS6jTwdQfjnlJBKmDxfRy0ZEC1YCLcILm632CkVePMrosRtYtZwDnNcbDa4EjEOk8grXdgL03HJ.2TlQnQPW99zUtYs7GgHAjCJK6w8fJLFdioarFaPgF_hAZFQ7.ye4R1EDlJipCCJSATiTTBJx98VO4tOvUSOpiuxWEmFM7EgP"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=91353fcebc37f882';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, "\/6967\/mla?__cf_chl_rt_tk=Uw80MS_0lALEXZ1kLc23vqypR80i5_ZLCLqztO_5jJU-1739789770-1.0.1.1-kDGOKCi07G3V6EkVR1qxcms63OdT258vYVltnrWTDag" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>