{"version":"1.0","provider_name":"Matem\u00e1ticas y sus fronteras","provider_url":"https:\/\/www.madrimasd.org\/blogs\/matematicas","author_name":"Matem\u00e1ticas y sus fronteras","author_url":"https:\/\/www.madrimasd.org\/blogs\/matematicas\/author\/matematicas","title":"El hueso de Ishango - Matem\u00e1ticas y sus fronteras","type":"rich","width":600,"height":338,"html":"<blockquote class=\"wp-embedded-content\" data-secret=\"vHGI68BGdJ\"><a href=\"https:\/\/www.madrimasd.org\/blogs\/matematicas\/2018\/06\/19\/145350\">El hueso de Ishango<\/a><\/blockquote><iframe sandbox=\"allow-scripts\" security=\"restricted\" src=\"https:\/\/www.madrimasd.org\/blogs\/matematicas\/2018\/06\/19\/145350\/embed#?secret=vHGI68BGdJ\" width=\"600\" height=\"338\" title=\"\u00abEl hueso de Ishango\u00bb \u2014 Matem\u00e1ticas y sus fronteras\" data-secret=\"vHGI68BGdJ\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\" class=\"wp-embedded-content\"><\/iframe><script>\n\/**\n * WordPress inline HTML embed\n *\n * @since 4.4.0\n * @output wp-includes\/js\/wp-embed.js\n *\n * This file cannot have ampersands in it. This is to ensure\n * it can be embedded in older versions of WordPress.\n * See https:\/\/core.trac.wordpress.org\/changeset\/35708.\n *\/\n(function ( window, document ) {\n\t'use strict';\n\n\tvar supportedBrowser = false,\n\t\tloaded = false;\n\n\t\tif ( document.querySelector ) {\n\t\t\tif ( window.addEventListener ) {\n\t\t\t\tsupportedBrowser = true;\n\t\t\t}\n\t\t}\n\n\t\/** @namespace wp *\/\n\twindow.wp = window.wp || {};\n\n\tif ( !! window.wp.receiveEmbedMessage ) {\n\t\treturn;\n\t}\n\n\t\/**\n\t * Receive embed message.\n\t *\n\t * @param {MessageEvent} e\n\t *\/\n\twindow.wp.receiveEmbedMessage = function( e ) {\n\t\tvar data = e.data;\n\n\t\tif ( ! data ) {\n\t\t\treturn;\n\t\t}\n\n\t\tif ( ! ( data.secret || data.message || data.value ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\tif ( \/[^a-zA-Z0-9]\/.test( data.secret ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\tvar iframes = document.querySelectorAll( 'iframe[data-secret=\"' + data.secret + '\"]' ),\n\t\t\tblockquotes = document.querySelectorAll( 'blockquote[data-secret=\"' + data.secret + '\"]' ),\n\t\t\tallowedProtocols = new RegExp( '^https?:$', 'i' ),\n\t\t\ti, source, height, sourceURL, targetURL;\n\n\t\tfor ( i = 0; i < blockquotes.length; i++ ) {\n\t\t\tblockquotes[ i ].style.display = 'none';\n\t\t}\n\n\t\tfor ( i = 0; i < iframes.length; i++ ) {\n\t\t\tsource = iframes[ i ];\n\n\t\t\tif ( e.source !== source.contentWindow ) {\n\t\t\t\tcontinue;\n\t\t\t}\n\n\t\t\tsource.removeAttribute( 'style' );\n\n\t\t\t\/* Resize the iframe on request. *\/\n\t\t\tif ( 'height' === data.message ) {\n\t\t\t\theight = parseInt( data.value, 10 );\n\t\t\t\tif ( height > 1000 ) {\n\t\t\t\t\theight = 1000;\n\t\t\t\t} else if ( ~~height < 200 ) {\n\t\t\t\t\theight = 200;\n\t\t\t\t}\n\n\t\t\t\tsource.height = height;\n\t\t\t}\n\n\t\t\t\/* Link to a specific URL on request. *\/\n\t\t\tif ( 'link' === data.message ) {\n\t\t\t\tsourceURL = document.createElement( 'a' );\n\t\t\t\ttargetURL = document.createElement( 'a' );\n\n\t\t\t\tsourceURL.href = source.getAttribute( 'src' );\n\t\t\t\ttargetURL.href = data.value;\n\n\t\t\t\t\/* Only follow link if the protocol is in the allow list. *\/\n\t\t\t\tif ( ! allowedProtocols.test( targetURL.protocol ) ) {\n\t\t\t\t\tcontinue;\n\t\t\t\t}\n\n\t\t\t\t\/* Only continue if link hostname matches iframe's hostname. *\/\n\t\t\t\tif ( targetURL.host === sourceURL.host ) {\n\t\t\t\t\tif ( document.activeElement === source ) {\n\t\t\t\t\t\twindow.top.location.href = data.value;\n\t\t\t\t\t}\n\t\t\t\t}\n\t\t\t}\n\t\t}\n\t};\n\n\tfunction onLoad() {\n\t\tif ( loaded ) {\n\t\t\treturn;\n\t\t}\n\n\t\tloaded = true;\n\n\t\tvar isIE10 = -1 !== navigator.appVersion.indexOf( 'MSIE 10' ),\n\t\t\tisIE11 = !!navigator.userAgent.match( \/Trident.*rv:11\\.\/ ),\n\t\t\tiframes = document.querySelectorAll( 'iframe.wp-embedded-content' ),\n\t\t\tiframeClone, i, source, secret;\n\n\t\tfor ( i = 0; i < iframes.length; i++ ) {\n\t\t\t\/** @var {IframeElement} *\/\n\t\t\tsource = iframes[ i ];\n\n\t\t\tsecret = source.getAttribute( 'data-secret' );\n\t\t\tif ( ! secret ) {\n\t\t\t\t\/* Add secret to iframe *\/\n\t\t\t\tsecret = Math.random().toString( 36 ).substr( 2, 10 );\n\t\t\t\tsource.src += '#?secret=' + secret;\n\t\t\t\tsource.setAttribute( 'data-secret', secret );\n\t\t\t}\n\n\t\t\t\/* Remove security attribute from iframes in IE10 and IE11. *\/\n\t\t\tif ( ( isIE10 || isIE11 ) ) {\n\t\t\t\tiframeClone = source.cloneNode( true );\n\t\t\t\tiframeClone.removeAttribute( 'security' );\n\t\t\t\tsource.parentNode.replaceChild( iframeClone, source );\n\t\t\t}\n\n\t\t\t\/*\n\t\t\t * Let post embed window know that the parent is ready for receiving the height message, in case the iframe\n\t\t\t * loaded before wp-embed.js was loaded. When the ready message is received by the post embed window, the\n\t\t\t * window will then (re-)send the height message right away.\n\t\t\t *\/\n\t\t\tsource.contentWindow.postMessage( {\n\t\t\t\tmessage: 'ready',\n\t\t\t\tsecret: secret\n\t\t\t}, '*' );\n\t\t}\n\t}\n\n\tif ( supportedBrowser ) {\n\t\twindow.addEventListener( 'message', window.wp.receiveEmbedMessage, false );\n\t\tdocument.addEventListener( 'DOMContentLoaded', onLoad, false );\n\t\twindow.addEventListener( 'load', onLoad, false );\n\t}\n})( window, document );\n<\/script>\n","description":"Hace m\u00e1s de 20000 a\u00f1os, unos hombres tallaron una serie de muescas en un peron\u00e9 de un babuino en Ishango, en el lago Eduardo, cerca del nacimiento del Nilo. Esas columnas de muescas representan cantidades que nos han intrigado desde hace mas de 50 a\u00f1os tras su descubrimiento. \u00bfCu\u00e1l es el objetivo del hueso de Ishango? \u00bfEra una primitiva regla de c\u00e1lculo con la que nuestros ascentros med\u00edan las estaciones y el paso de los astros? \u00bfY cu\u00e1ndo surgi\u00f3 la necesidad\u00a0 no solo de contar sino tambi\u00e9n la de registrar los resultados de los c\u00f3mputos? \u00bfFue una creaci\u00f3n de las\u2026","thumbnail_url":"http:\/\/www.madrimasd.org\/blogs\/matematicas\/files\/2018\/06\/800px-Os_dIshango_IRSNB-185x300.jpg"}