<!--
function random_imglink(){
var myimages=new Array(4)
myimages[1]="banners/nature.gif"
myimages[2]="banners/accurate.jpg"
myimages[3]="banners/physics.gif"

var imagelinks=new Array(4)
imagelinks[1]="banners/02/index.html"
imagelinks[2]="banners/03/index.html"
imagelinks[3]="banners/08/index.html"

var y=Math.round(Math.random()*3)
if (y==0) y=1
document.write('<a href='+'"http://ejbiotechnology.ucv.cl/cgi-bin/ads/track.pl?p='+imagelinks[y]+'"'+'><img src="'+myimages[y]+'" border=0></a>')
}
random_imglink()
//-->