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: "publications.waset.org",cType: 'managed',cRay: '919a938f3e5540d8',cH: 'OUSoC_VW52mOEw0jEZMzJVbasKJF4GjXarhdjBH8f94-1740852262-1.2.1.1-L2EsCqy0T4rJa.NJ4sTsIgD4RT3JEEYOozp4GHyLnoAxZPRaxVMEWzmb4ZklzLV_',cUPMDTk: "\/abstracts\/search?q=PULL%20principles&__cf_chl_tk=5KyN.zmFG6bKske0cKauy3KRf8j16RGEE2BnnuGFNHk-1740852262-1.0.1.1-lVU351ikM6ezHdxV6a7kKnj3wYdy7QvMDpTIKGQm.kA",cFPWv: 'b',cITimeS: '1740852262',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/abstracts\/search?q=PULL%20principles&__cf_chl_f_tk=5KyN.zmFG6bKske0cKauy3KRf8j16RGEE2BnnuGFNHk-1740852262-1.0.1.1-lVU351ikM6ezHdxV6a7kKnj3wYdy7QvMDpTIKGQm.kA",md: "6zePsRq_NSuqttChuYHhByu9MbDPS31RsyYYRur3LUY-1740852262-1.2.1.1-ZMYxr1JMM9DsNSfJ1_MUR8_8LROQSnZGU90WlOwBiX.32TDHU4ECd4QJ3akhuTMcHfTrqldZkSsywIvY44OUVb1sZry.mHgQMav2FB696dcGP4f5EZ.aFhw57vI83M7duVCq9M1j6HFACLr2TTRrPzgp5LEZjFUg70YsnnXNC9dyDjxzj2sI69LAfimsHGDvBrJizKZr.XRPg_Ng0r.ykxVvoogjilNIffGtJhCo_dbWrtMn.J52J.3vwBYHpNARDkXH62hHN5QEYWxOKnhRmTs5OeBRdu180Oma6Lx79ecdqK1OZx514ofjp5cqxQD3KCRW7FHPagCQn4802OBK57dDpkICedHmVaXq0bX5iJykDizFYfiDfEsIe1z7a6cbMGViLxL40rKHZthGALHlRT4LcC_B8oVJplPz3uuJxNIFnTiv6_ZgEQmbhQWisxMGovmjmwTRmfatcgM7VHGk0I6bPb.2a74l5QPqfXjITmqP_D1jazFlPDl.6weLXMfYUmPHhur68LKeWJUEE0zfjPkKPccdpXeogceEpk84flnXvRd8C.m8LzQpahGtKbruYa7f3Oiix.Lo._rHdmAfeO2QJhRQG_eIBqOs480VdD8vrEo42KbtEMrl9ajNW.L3sJ70gBZTB6XeUJHNjPnWcGq7yYtE32T8PI2OoCQ0UwIKnbYICu83xpSXhMcoMH_aIAM.AoqZuqwJhB.XIjB4LkTRVs3KMVbet74pkaw7ib0Ba0.xc9_aLg71_Ynj0zBh11wNoEdHxmtWP5TbRVt6.CjzkqPsSxup8xIf.vfg84PlyFy1HOsLZBHKYqVrTjiSviUXuU566TJ7j9Hpz45Ur3RDEMpPoPyTdaFvnmtEQwxYV3cyNtulCUCNnqLu22qOe3dRMPAkYR5p_1HsyDWQwQ7ZctenV4MfdR83JZY8.aosPrB9t9.xyIlgm5zZAws0OpHdt_qBLzFWAYrPNNL95LSavoc4cVUTgLwLL4Ek0_4rtdLpCig5oD8XbMLv7rtZeruDfb5znXsKAYZv6Z3LJCe67TOFXUx9ZElRp9cufcCr.lkCWuHOOL0LlkHF1i5BYewCwr4EGALwOCk7Isjv1qgIUgw9KdOEZjTAa2smw14_By9Q3coGX_cxsKWTPXsYMFNpObqpLf9dGm69Gi8NaLoDwFFNccsxncFg8yiNVfU5.0s6YU9B9DS.v2QbXsP8EMag_jzGJ2XGxdBZ4GGNEAeSI2a5m9O_vkPbN4pwqp1chSDz2CHnCf5Y3j3cICKxjQ4X892__uYvV2tCAkbShg",mdrd: "f2FYeugv12tZ3CYHEa2f7r_wsspnVRkauDLCutgaGoM-1740852262-1.2.1.1-F_CC6JHgul468c2o4cmG5TU6KavSDBD1XVa9RBNRugKr.uLPWTbpj2ZSjEWzOgLOx46LHt3N.jSggcxnwdBGoTFaquANUmchI1UfhmfUVX4WREAn3m1tzI4zyqCNMj0ALINYDE13hfQtuxNyb7ptDQjG3bBQrh8f4xvWqW3iM4M0zvM0KIek2gZolurjtVHHiD3AFNIgN2YIIXRulIp8gs9PlYfEDpp09Fys4CSDHKDgNq7nDAiW1VXzcnbB62Mi6gYBWBYcVD4zpDSeuhovATmMmdrePTrRQJnGqknqHuZmdfRt34alYL3Jfnie3pcHMlEwkz5cnHuSog_iqtC0WQMp1ZDtoeBkykNKa46ryUpmBZiNHDk4SezyeEoE.tkNfdq87ggA3ub0_3AXsgQsBcrdbjxG_T35rW1GTzfZYrfVhP3mk5.AS7fswUYKsn_FrI._w8ezJhw6XDs4QEJvnSvKkOjI1sUmZ9UG0MrAvxFQqLR1T5OA0PDGSHZAiUEyZJd0cPR1PqKkjsSixDGLdEBZ89JU5FWXEKtccMPs8iYv20.jW1yLuzz28duKe6CTQphuvaTshkGk3qcyueSQn9uC5scwO85cxJcPnXxIglGAtS1nfiYO16E7r52WKxthyB0CSZ5FGKQedvVEPnrXc0Mkp_dQea2RaqVb8gHQsvq.xQNE0ufwGILmHSj4thW9OOXLVGM3xjUSttIPWTTpHAZrUQDzrjN2GM0FWPkrl7O95J9uNbARHoUUiDx7qIbjg.de6q8LAA41OVLCjJVEFTz4bpW8SJ9fkog1NoMB_fRzpfUiVE.LEqQ2Buvxz7sNX6IA.dv4qDgC.Fad2bfQqA.Ut0EIXaLHYrb0Ke.WOiKTEnBiwrAfiBuAieJMFNAdzFqEnB71Jt5daxFduk73gO9fpjGauUZeCW9GDGaaROTQrRl68qp38a7q2olBt3KJkwBokp7uDf7UEllW73PkG8f9kWkXaq_5PRwhCW7wvjaa.7ftj0.N68HG_wC0YWYS7J2Im6Am8tgcEVJ7sh65nQlQitGa3iYf4_NpA2zJdL8o.b15LMru1cUP_f7feX9t2hgbkkZf57FL4fkKvHiWOjL.OneRRrY7CBMqD0XXwmxDC2.13ZgqlOKg73YzThJT7ByuDXMoPofoKh95CTlDTPLw_4YSOulsXVKaOVpcJkebckA.uLWxY.UxFeOrLt35YirksXSNOMDpiAr6iM8qnaH7wJHPT09gvHOAODz.Bjy9Yc9Fqtgjy8L3iZGsG0GBAdwF2pacf9n69DGYcTeP54LqY9JimuJBb1BLskynMFE3ncva.PR_HC_stYp4LLNE8QrL2s_6HqlWLNLIQWU.X0okxEK6aMWdWAFC3S6RrV8PHMZc3XZFavNPNqebI3TDqTgC_L3yplIOIdS51m9iCQBtf.uBlTSFacygUC_eQz9fO.5nT0Pd4Q1qf10pJRor6GPCjO5UHX3BuGAmC8kBlw_utWXZgaJwkVvggmwj.yCuPujf_O_u5bk.XRsmXF8EQP2r07fRgqmDOe13W200tX6F.l_chgPPSZ_MpfVjgbodMrfCmGh4v0OB0pVONk2CjVwEUOOWb8FfUii8wLalRKRbrJ9uIVeWPTxHVphvOTdUh3nFZkfNYZAmBQ5L_4X9k3HlrnggJMLXnAl52nXISSagbo6ko.R4pmGgzW09NtZ2s5I_sZUebi1BHp2KyQdK6xh_vI8icnHaD6i.bKWCN1Nkxx8hJ1XEFyJFRl448nd6Yn1vwqcBE5lUvWPUM2DO462dfFaXsl6UmANEhR3zdFndzh1J_0B5b4_d6wiWhAzSqPvDiq95Gy.RTQ1gx7ARqYqneAXFxSkivO9XBbAcJYoQ2cWIgHJcnDRkwhrZWfKnC46LNsU7_HArz8NkmjzP8BE9JTc8zWYa4JuFSisdcbI8tEbzrZaqjy5EeYBfS6HtFPJnev8OIwXj1pRMRSccgqA8OYjupShUm9qqfdHx0g"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=919a938f3e5540d8';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, "\/abstracts\/search?q=PULL%20principles&__cf_chl_rt_tk=5KyN.zmFG6bKske0cKauy3KRf8j16RGEE2BnnuGFNHk-1740852262-1.0.1.1-lVU351ikM6ezHdxV6a7kKnj3wYdy7QvMDpTIKGQm.kA" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>