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: '9135234b7c683e14',cH: 'xwJiygNsJxPFnH4T3jhR_jJ3tIMIl4Id64YXt53b3Wc-1739788602-1.2.1.1-Su0e48TTPUt65Km4LtBny8o2jBskPz1v5pc1GSDKLuIPTrSiyu5I8OPRAsEVI3DE',cUPMDTk: "\/abstracts\/search?q=Anderson%20Ngowa%20Chembe&__cf_chl_tk=JIUaELtVkMr4sZKjOQeT_HxBxWIYpFriMEU8dJySpV0-1739788602-1.0.1.1-VLnugiHSZOnp0DTlm1j2gEYtma_tO06U5tIs44zFa9Y",cFPWv: 'b',cITimeS: '1739788602',cTTimeMs: '1000',cMTimeMs: '120000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/abstracts\/search?q=Anderson%20Ngowa%20Chembe&__cf_chl_f_tk=JIUaELtVkMr4sZKjOQeT_HxBxWIYpFriMEU8dJySpV0-1739788602-1.0.1.1-VLnugiHSZOnp0DTlm1j2gEYtma_tO06U5tIs44zFa9Y",md: "tSUFsSahKwubbm7qDvFpy5f2BniD_XhQIV7Y0N8NznI-1739788602-1.2.1.1-nxoqK1uH5aL.WRsWAyOEcrl7E4d1mMOqr8xGvkL6Mps_d.O6OU7GZ5JRMcnPlKm8TWSP1xb8ugPqrufwAydnCzNo03Gvl_8GHYlq482M973weJonWXdg9vlWcrnqQ37WOBREDVchHOcY1pHsQNTXvLs.e8z9vTcvc4TYNbixknuu3lz739MrA8xNilFptJyoatO9r4jW29DFIq.7I8yTaa6Mkb2GJ_owavMDKxU76qe4wB.Cmdh._sf4nSDJhb4qrIaZsypaoBuQfJoFewjjjGEio3oBPXowzybEflR4.9gvqYB22sQIJ9OCOrh1Qxob.k9jQZAtEUoDtAnq51I.IxAkinbTUIRlyt62wko3V_H8sY15XufjFr7KZoDy83XpdmOBi2_wq9j3aJc76n.Unn48199xy53AMNldh_wzHVlGeqSKDPmu2XxfKZJVQUOqFF1rBxiriaDfR5tT2KaLu5oW01g.LWVPB29SkEHbMXsMrmPy6mA6i27y1_z4DVGo2J6MSqrLRZgS3Zr46UNS9R14QDqa2OqhmB6tLfUtX1LlIB8h7Jw83emK33tSzYw6plCg59JLmia4aXuw3u0x.40h7xb9fnZ_3bXeXzAQ8_WPHyECH4gRGW1ii4eF.EeUPFT3PcDWa3VsE9HbjvH_TUtBCv2D5tkLk1uYbEg807Q9MgAYmneq4IkrGUHJl2kK_Z2blr310Y3uRafizNRHXRHqMTrpQEm.kGHkhr45c21eDdCdvZJ8VNiQSf7tLMyYN4O97Uz0ym_da.4BFgguBfYG4g3ZGRZQW.2kx8vtVK3byJOjtaM9eDb9mMkKoJD2RZbmncl0dHDuecZuLbGCafCbOcNZtL9GHzFlU4rAQnn0jt_ewD7bcmsM1tWe.DNtC6lhR82fPAUP_d1J3vMiTrcESe5wWS9bUcmcEbdyp74c1xAO3Z5vgRZESCuMygTtyLkkMOTAUhbrX62UTlE87doo0DW5f5_lOGzzcR9sjRfgrIQj_h8dGe.JaxppXhfoLgoJrokXfUVd12.5GSj6CS8WNFoKqSsoEOjYeG1N6Z6evjuzq7el60.vNrO94fUUYlWCjvGRK4x74EqycKrzWGF5tGVlPKlDLr5nS_sPskLZqNzjxVRJWCDJ9rQPiBKujI4QKtBYF_DYzsR0.8nO2IOw6psh8qL4xuXrNczHNlfWJPruvC.9ZpzcErKro6mastHu2gEoMXMCUXCU2QBKcPVkO6ip.A9f_lwmwdtTF3sV1a5xAFlAkuHXeIk7Ggqg0Ls6NzdG5hAWOSeGG60X3JUg321HV_82QdvkkvZz_bgAmH_eG_1NimOB6bfDtxi.SXs9PLiFvO9j5ofYovJ1ZYOMZDnNbBinBMoMz5ykVdqEs4KrBNweGEV_5htH1MDyJ5nmvu5fhmqGcmhgZzwNDqVIKn27w1mCQWUcJlBiLWTr3w7yWTVfJHr7fvqEa5z8TWbNFuTPm7YlerkS7QtW1bMY1RjCw7_f6Fe4dd75JuKVUPfm56RmhhHfrteNdI9Dw_Mt9ZveFSwNCm3SvShXH7aKw4DI20Sbk_YqLF48j46lQTFt1Cem17FGRVpGFkzUDKZuuYCrTkgxZz9t_tu5lEthFUZxnidcNuJUjQoFmC5oKty4QLZC8hOnqvGdEFfVoYAuG4uCHEjRB7DfQdN9MNCMBdGis8TJEtVbvgyfwfwdusjA7BEqYDIE8iQFozDY9iw4iWsQHiICF13gtZtakQDfVIXoA433EaPnWYeQOXNwc3Nu2dLuX4rH_WjkO21JP_YEpMrx9jd0RG4dLtZ3xLMq.FZ5QDvfgU1SzqNzHwgl6pEyaxRJprglkMTYqCmtxOgtqZ19uH8_OpjKAuM08Oe42w_9tmkiQ6SR2LYhGygVT_7wIMG0jV8lZ5K9c.RB95rUqvk6nTzlp87zGFXvYCGXf2kuvT7pLgzOhDKnIkf7CZyjqoNvhLQ6GR2ZIIS6",mdrd: "CB1b_.sA7Jo3PFGx2I_tOcwS.fpDo3Rxt.Ql1l3wVCk-1739788602-1.2.1.1-560MLroMIjcb35xmvi_IU0rvrTL2sV5Ie9KyHXeKvou_QmuGg7g7jjMO6QH4pOOuxrlZGmwtBI9fb91.BLu0cgCH6GS5fT1s3zS8aC.PDzhf7iXT.0HI0rQMvbCGGVL9gc2nt78RCPI6xvROuxDFFFjcvRtkLS4pyBavFvdu0CbV5vEiZ8UaezA1ZGsCLa.PIDaqR4bNRm9kiW4I3qYVRo.E7CRuZ3RUlXpz1Ccpm4qEzmsXmKzLAt.JTxsBYbsYvdULmPZszu8NJ_YUClmm906Cx.yporvUBQ5_EG74jztyU0O2_YmfUBFFNrlyXi6Q2TI__FpD7hdTg6PtzUfff4Ju6lCx.ouG9Y4TTY4QNch8EtNEay1D2ojZ0BD21sL3latoGnK4QLzXbmnvWuGAx3QCM6HDzv1fMoX_vD0OSRHxnul7Cy_82Yz07BvFSWy43eLfz1cSHLWLJlevWt2nCmE2y_9fGSEjC69FUdkhXPWaqEQlCK7h30sJRbxFUhQM2Qu_fFuQFvrygquNrYJyjwah.okIr6P1s3K_rd8P9CNe6D8SKZ6Q4BA0RfcYsCCYP.34rlEcOOtS7dswwHtpOzJ9ARr83yLK258FVClym5FJ8sZOz3RUpvOmlZuZD1NuLgTGi11mEDzBdZjfelgVz8fyPHb9YnG4JbekqlM1LUWNp9NoL1u9jOiPNxNDG3nlka06b8pYTXiHWDdImwIYMPw8KRNNnr0UTKf_b0Vdl.h3z7EnPNZC.TnB3f5cOMTqIvwMFXrAx73pqi7D72sWy7y8pS9HOMQ5UhDDUOgHwCqisrFeBVQfe05LWyDj1E9qy7vvTpOB365HEoyTO2pUjHiHOXsTn8LoqUmu5nHVdss.QlZXzMuveW2_gtakNxawrvOZvMolNlBruJ0R28d9A8dHf_.qjY8QujYhlxvq2FFT24PhsWooqFcdZh_rtGRcSraUa72tFls6GXGrqBXAGKvBleOmRlYArtVL0h32iX8NCEI68.kYqt9PR6d8JnHvKs6pxP66ZEWUt.gOuV21fMhEdywqcsoa38JoYk8ceaUZh8AH5WY7fEBTE3WHmmOIcahzqOxRLv4WjQ2GC_BI6cG0qPOF89oZXSVAkmTmSasTHGlW0zDp_tYGJIgE64L4hMIavqNWUSMSHUKSeTnmfS6AvQ2lWosGW5jxt99ZOcVsugi.HEcAG5VNEr5ejBux1l3jNAB7OONDm5j7f_RuxxRi7F1b1mAhrUHR7NgPP74SkqU6btUveXvgEp_HYll7ZQvbAACp2I3VJqa74w2Z4uLxKQGwx3IZAOSNHHi4AYsdk3itax2q7TeUxc_HKoYWHkCPLXKh_4ns_yQl9q7FYG2Ijn51FIsTMdTSSm3EmgDTl0jyoursx_Cwnkt.nOXlZt9wlMvBV.CJrEz5hzWOc0pa6YX9qLmz0lmYhcpeNS5J35DfokKPl_EVx6p7ZBS5hy4G2bjd77zWd6CYAIVfEGl585vQLOwe9TZvM71C0fb1n5X0coIiySfiGjYM.l22DrbgJsMV732ozkAP1ySltHqPcEiz3x5DUoM6PJ6WSnrMelaqCZd_A5At6puIUmUVXzcwhYLMI14Xz0Gc5DERemk4mxOOYLipT.elu1oRjx1Ki8UsP2qsCaqBBFhG1nvZDqnvkWTqbBApDhdMw4WAnDeNVlVdYxK.FMJXkY7p2jE6Laq.JjHEONLJWQYChX0GnC99C_VOtbgl0BGnjBDAzoM.LvOGUmpyrKXnwdFQeTMzOENrXz_KU9ZLerheFfYoXDFrwrwEjoUGWJ2maPLwHMbvvtbnEc.V9DijQj0SCDnREUL6fcU6PB5V9SXp5hkd3whkj8hwl_dxg4fy0_KQimPuwKr.ZptaKHzntdxa7VS7SncqLrbAv69js2FJjXlHUCAu7QR_SAdKK5DVn7tMf5w6o43eQOIQ2b6VWtiU6y6JDt0bwBRelBe0SWw0Y2sa"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9135234b7c683e14';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=Anderson%20Ngowa%20Chembe&__cf_chl_rt_tk=JIUaELtVkMr4sZKjOQeT_HxBxWIYpFriMEU8dJySpV0-1739788602-1.0.1.1-VLnugiHSZOnp0DTlm1j2gEYtma_tO06U5tIs44zFa9Y" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>