jlh is, I think, completely right.
Actually, a crescendo and a decrescendo could be done on a single note here. (NOTE: I'm not talking about a physical stronger/weaker, I'm talking about what the listener hears.) If you delay the note -very- slightly, accentuate it with the same subtlety, hold the LH eight a fraction of a second longer and accentuate it as well, it will make an illusion of a crescendo (Perhaps how a clarinet would play it?). The decrescendo feel will then come through making the second LH note pp; the RH sound will lose volume naturally. The illusion is then maintained through continuing the decrescendo in the other two RH notes in the bar. It takes quite some musicality to get it right, though.

It does maybe sound complicated, but it comes naturally if you know what you want to hear...
