Iophiles should like this one. There are two new papers out. <br /><br />The first is by Matson <i>et al</i>., which was published online today in the <i>Journal of Geophysical Research-Planets</i>. For those without access to <i>JGR-Planets</i>, this subject has been covered at previous LPSCs. For example, see this abstract and this one.<br /><br />Rathbun and Spencer have another paper, entitled "Loki, Io: New ground-based observations and a model describing the change from periodic overturn," which is coming out next week in <i>Geophysical Research Letters</i>. For non-GRLers, there's a preprint for this one on the LANL arXiv preprint server.