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="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: "catalog.aap.org",cType: 'managed',cRay: '8e8f488b495eef72',cH: 'B3ilk1qo12lkNPJd1wBGW3ZC8jDGx761Zm0mmrpSNKc-1732680782-1.2.1.1-LCh_yJgL0MqjpdxszAaO5ZuJXmVU6aDEQipZujJqFqQIFSv4JcKvNNG6Wwee.XnG',cUPMDTk: "\/?__cf_chl_tk=lnQsbNGoEtV7IEOFM.T9tCQvJkqxPO3b5paCHLRvxEs-1732680782-1.0.1.1-cHcg3M_YRxbA7FBUWE9F_SqdQ50dBpwxoeFU45jqoIc",cFPWv: 'b',cITimeS: '1732680782',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/?__cf_chl_f_tk=lnQsbNGoEtV7IEOFM.T9tCQvJkqxPO3b5paCHLRvxEs-1732680782-1.0.1.1-cHcg3M_YRxbA7FBUWE9F_SqdQ50dBpwxoeFU45jqoIc",md: "9YfbBdj1N9GmhGkWyN1eyKzzvdQ.JCXxCSwM2lPEHPY-1732680782-1.2.1.1-BMMpVjdfZepOwSoI5o0Q4yCQt.26KxOg1b.I1esMHNYlMQZqZivIqQ.B6JmUZcToQ9milovXQnA.zIqK3445XuhZHfg6.GNIU2zGXEMyx8_QVMoRZtM0iZcgQSlprKy87BL20OmzpKB7Yyrbuw6uxFKkAu3ho5hl27Pb6Djw7AtrDxdU84BOAhV7wleSTRzFB0.e5FsrUe8BC36V4eiSpIUQuun8WQSUbiEncJxBB915CDjtX6WCJYgIxYW3upVbBC7eUreA9diKkDUDsAfEy1xS_93hm5h7aYabzI_GBuvMRaYhA7LAQLJqqram5HmGCGLJytmIO6PAEC_.az2xke4EVx0OgPrtFQon0unMfP7L2Z2UUHkKgVOgb4GD4AFotJShfrcznIZGZa0wY2BuwCkTUxLGZ_kyk6SCJtV3gUCzJrLgJG7zRqnvR2Y7zE3QF9JEUSWusoqHjjbMSo9UVpa6Fh_lhr368LJ7cE2K0myyAj7JQlzxE2h6j58396Dv0yQ5_EhXAqxzHbxPoYRp0gZJYc8IdD4kl8Bf8mNkUqk04DDnHMP.CVg4OZEiJa0Wrp7GZH09uPjnh7tMNKuGJDvZrb1MSITsc7bV8ECyxGzMRWv2HKIoMaDeOa5xSaf_uzMBn8cNorR7ROBJ0Cphi8iu0e4Ra0yLfHdewBsuotx93ulrPHgr5auKP2jlVR_Yd7qOCREcVF3ixRTePjYesm_xNQBL2fp0zOZ3C164SCNCYOUq6VvpFJeT4AisXWbWjbF6Y57BXHnN9.XkRsK6mc.dPA6ukOWgbeSB582ulaU.SeYHn.UC.BL._HnHlmJ9OMrDnjzVAztnviiIzWBkSN2b3dvxeak65OXrtl4SjEljXz.aumW8minp5EI5xOJVIXw9TPZoWX2oDMX7e_W.2kP9wSe3flpj9yGRZevb4CKMrQAeg2osaeA0FMgJd42Q6CXGJPmjn_nLaPcKORyppnyKRpgknCHizJGyP6CbBiXSYI6AIoZhksZDXKuruB_A52apNR1xKQ8aJ2Ds_W1BwVCf2xXVLpEH0GXVxQBe81RKjZQae5GIz9H9KApG22laI5F.7QfIjDhCSf0BZrdv7U7PtYFvSen3M3.zrdmoDZZuz10iZ6A.92NDqJuo.qTDARbBKTuH292REPZIR.ODP7.hesbmfTOSW2kU6ajxg2a6GUbJef4oIzfDcBtZE2lytyEZAZRpTjuSeTKVhWN8F2JvGJtehPvwlraKXHBdLNdVU0CfYNLu5rfUJA_4Cr_3R5ms.eg5Eam_l.8ZCT1KKc53M50NWACwTgfvXSpogWA0tcRz01qNJ.mTTtbTjsJcPsbCruI8MZRsLbrx3inRWZYrZeLMYH5ZQwMS90cbKCWN_46VYira5YgyARqwsXablNckUiiEZ_HR3QGXlaGVjjJqZzY4_l9HYAQ8ow_UOUfeOonuJfaPy2sp3eWCErTEfvLkdtj.k88aTBpt52T5V9VE34oGZvGrF7ewH_U25u8ipzaWtExNFF3D4tetQbo2ygMpzi8wIoQajXWzw89g.OuZ.O.bjknKnnNMngR6u.ueIksRLzB4AKLEaA1PVY4XxdGi.wo3tlWUOHkKnljOfdMyuURwMlS0AR0hnPWjmgobZ2T_ym8S1shBM6j.9XYyXXnQoA1j357Sc4g.2bJcUMUCmRMbn_y1zQrUC5KAGQK3K7kdUwJahHjZDoeTLGh87hz6_Nd.PAXSSYokiHCewcTINRBb1JZ7j.P_52CtDbnnDAGtAd5XmDZ7V1DdTo.8NVHXcdYbmPw2uAujYAonoIPkuPhNAlbyD7dRJMBt_4eEUGX3Jhi1SsnLP4kb.liUUmAL9tZJVT7uaPF2cHu.A6zVTjvVKJPwwJEhM.7oC0WUHpzaGFmGvvSMbXvoWfQ.Tv_IwBkOT7RckTrqDZ9CyQU5dr0cfzuuTvYhfbumyVEl.AAMk8OUSwEdyW1Pl8pHeuy2loa.kN85Sl1ycjXFJ.U..UWzNULCh5JqIcDxunKLHLF6sEYtsWCm.55XVzN_QQVTs0Eiq0WMx_xCAoS8uP84x5CfEMQeGN5b6RVzbZ8dgxDxseUN2mgmsU_OuDU8NVtRDmGbKqAxOCheOsBtN0nPUMaedi5z7aK7nvWjNPD2V0gyzRGKNB5_wBHpGvV.5285VRSPPcnAtSz2wUso2sXQTAMOo8TL..VDjVVcKr_hf6weiJRaXs8229OwHF.KC4E59KDJvIuVYnakKr1mwJjW16walS62Ic1biTarAasVjDUHx4HYuQ.jX7OoiRI_MS_9XhS.4SkQywhIztFfyi4X1zZCgc66XlG4Z0vOCqdyJxxvEZXl_3SKqFqaTbs5gdTRzHCiJsU.I4vDtmnLClw9KIrhCqqxcga5wmmdLfi4yJMK7KlaVxZ4fXGzVBAAyigKmTfDJa4D_aSJuzByNupgeRa6gBd2Yk4K0uWGrTe3nKDRP5ze9yGD81zGmdFZvT_l2XG_HbEmi08RHBXKBP8XfqqtgvNp2pXFT5rN.o3zAB8PItS8UGFNPmheXysbDq63Sn5B4hCRtIU_FSCnnQ3K36TDG3hd0FQiaiylNYNZAe5r3QS8gl0VkDyMmaBKmLjfjsCuGLdJ2f8LiVm6bZpT50q0O6jtBQHSsKQgtu_KUgUpMCEvWffVMcvlHrUOIlJM_gSGinNa3PzCZhe61UX7PbI5rxsoKlBdm17sZ_EES26fV8J4MycI8xdyNXy1ShFhrVgarq9B_qwkEHILE1xrSpaPbOc8SFaoxSxwV1NNjA40rTk24IfTOagcxjERZklXjkPpFy7iQlZ0s9Eg9XuYrh.cNSaNE0JlJ6c0fAXq1CwWvwmhK0YhJGgbM_nd",mdrd: "7Uhc0BfGun1r7q1QnnKI37pa0REAi8.fTwIZzkIWrEc-1732680782-1.2.1.1-lNp4fbF4v_NVSe8vbwVXtPq1U.r01mBjOuVvwOjYwPCfktkecNSLuVa9qhkVmacZ2879EGMb5tk.tqdiYHczcv.lLkByVc6vrxOO8jQSaYONnqfi5rmd6_bySb2TXWZZKWCYTU2RiGvGKy3yAGVfUvD27gogRIq6Wi2Xx01MrusmXxsjfFfJVDWw1FP2DVMv4GxUoV2IordwuQzPqluF91UVdzrfD1qaU19HVW5L_HNOgD_AmAVkLe2a4aubBCkTTH244CLIebtsixUMsEOuIg5_2eN3T.eoYuWl.lLuhVqiyrafeqwL6Gq3HKFDES70h2ncOKrs5dABmYT9r3KgGlEMTLxiT3SDyZLCO0qGz04APyB4DsBXEa2LJsl1ZqYRxnYlQhnd6ImhbNCacXv7vs6oTbgj_cv4jNWkUfJrXVBQHqZt0RdxoxcVCSuk3OCj3B5rrUpB9rCMPeVQikNN1GDNqJLLwI27rnJvXnhz5JJ1lpl5rTfAXWqn1WlhvNTgBe3zKSARkLeK58AUUIj.zI4NwmO78H_TJ9bt6XUFOfWhkJlEI_0iz.3gqfZqWVcY5ixPIG7JVs1CetkBGaBNgMK9opOwMxCLs9Ukg8j90pLTU7bpqeGjZXmplHnkvl5ShRPPPuatA1H22ly27vYqNT6L4NZ6EfSkAd0Ws.e.XDLYkXfbbRMiFdIRO_RneXIncMix4MPM4UHlqaSli1Wj802UWAi0x83P7dtaFk2POOPegoWP20YhbHTPDiz1bCUpGd0KknwIFGYd_.HwEOGuebb8CcguhiAD4yrfzZ.pOVFxjGFJ9izbfoUk83aHNVPkDVjkTbQ2LF23YB4DUXQrhFsgUwyI4K0KNHDqZGDQzTWIKJQm5HWCtfNWPlfIRK8TqktTog7B.ZgWZ3QYC_M7ixYkZhSRy4BSJ43WhK9EOZvkiYKG2CpTUT7iOYCQHTEIUb7FHv8YJwlQdAcjIq84uEbtkGG3Ynm0X7ANptvRTdQOx.dk90BdCynWq1XxQ8XJLMfMXylgl1PLhq9w6EoVlw9AI_1.bBJvG8oR6iYiwTo3NVQAKfjyWoH3J3czX91xH6aG7T3qxNT2xBdT1wzx3c73jBUuUTaevLnKCvbggQ8rmjwXPgrqyvvtMzHQ4x10BlxJqWlheahFiq9qGoWapl1Kn43qsOXJJoe5nwzy.ZqiF5ItzimfS9YDQL.IP0eDdnDz_H9EZS4BZpLsLU0XGiA74s3g6eGGLQUDsrzrOZVT7.WtZU8EXDSCTlyuwA.yD4ug1nDey41N1jMX2kD84h4i.CiVWHFGPsxiBc8tql4ZeubrSLQuMahOYe9R41Zkcq7UxV5uqUj3NUPUjsail83BjJ2S0S9KPrY_4XljlUUUr41wESYlqd2suyEVcq6.mYalXvPIny8xTC6.0UqnfG4pPMBoPSbGpTKN580Yk2K1oUtnf.qeqWe2zkZDTi3uvdnfWN7JpQ.v1GmnCq1riWajyUxGA1ijPFHUg4BcuynydRTNj.CXNb7dnFEfIB7pNj0ADEtOUKFCaKCa94ah72__q9z2YzeWD4ekV6YyYlb9yl.BZkhA1fH9JlA3QI1iBn9D3CNmMpq6jigbT472Ysvd6hv.5suoHPfqY8ENXPxQpyIfxm1jsXWW8qV.WJ2pp9.RZKbCkmmXKw514MHzVf6Xk1cK2JWiR39Aew7uhAirMheJhVogw0uRPtYLVOLqYCey6eVCxB.AsAGzMLPEVxxbvMLnI8mXHWCxl1FuHvQCeDKIHxMVBMxUY4td6Ikr.FHWmyzRn1LkspZkaJrbrynJrrTI_0jVNzEK927cRFj0Ugg0hhaVdv_0SafQfQqYvjqn03SyDWhalHEL9LNlLU1wOCx_D_3ixh04Pr2Y0boY0LJCjR1uH9Mfurfzd5BD5TxlUfFcJ3eBjun4jTbUcbPlq0cctUNKls1_7w8oxi8"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=8e8f488b495eef72';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, "\/?__cf_chl_rt_tk=lnQsbNGoEtV7IEOFM.T9tCQvJkqxPO3b5paCHLRvxEs-1732680782-1.0.1.1-cHcg3M_YRxbA7FBUWE9F_SqdQ50dBpwxoeFU45jqoIc" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>