function mostrar(nombreCapa){ 
document.getElementById('inicio').style.display="none"; 
document.getElementById('institu').style.display="none"; 
document.getElementById('docen').style.display="none"; 
document.getElementById('inves').style.display="none"; 
document.getElementById('actesp').style.display="none"; 
document.getElementById('noti').style.display="none"; 
document.getElementById('exten').style.display="none"; 
document.getElementById('tyc').style.display="none"; 
document.getElementById(nombreCapa).style.display="block"; 
}