Jed,
Thanks for the background on Arata. It is easy to miss that kind of information when only looking at the published papers. Steamed indeed . Ha! What an egotist. It is tempting to slide into a little politically incorrectness, and opine that his temperament may be more typically Italian than the Italians . . but let's don't go there. Jones . shows Arata upset when he realizes that Fleischmann and Pons (shown in the thought bubble) are making a bogus claim. The little cloud of steam coming from his head is Japanese comic-book iconography indicating being upset, I would say. He is "steamed" as we say in English.