physics geeking: nuclear decay

OK, so in beta decay, let's say you start off with 120/60 Nd.

You'll wind up with
120/59 Pr + e+ + nu
or
120/61 Pm + e- + anti-nu

Now, it was always my understanding that 120= protons + neutrons, and the second number (60, 59, and 61 respectively)= # of protons. What is puzzling me is... how can these guys be losing or gaining a proton, and have the mass number stay 120?

The reactions do not show a neutron being added to the system or a proton leaving the system. I HAD been assuming that the proton becomes a positron and a neutrino, but that doesn't explain the other case at all nor does it explain the constant mass number. So here's the explanation I came up with:

in Case 1
proton -> neutron + e+ + nu

in Case 2
neutron -> proton + e- + anti-nu

Is that correct? Anyone know? It looks like it works. But that doesn't mean its right.

Silly hour

I miss the silly hour.

My freshman year, I lived at La Maison Francaise, or French House.

Sometime between midnight and 1 a.m. or thereabouts, students overwrought with studies would spontaneously converge upon the kitchen and those who were trying to get work done there. One particular student always came for a bowl of cereal; the rest simply came for a break. We knew it was time for the silly hour when he showed up for his cereal.

Insanity and hijinx would ensue. What I liked to call the Silly Hour was marked by particularly geeky, pun-ish humor, tinged with a certain strained, contained hysteria. It was like a pressure valve, one we all desperately needed.

Anyway, I miss it. It was fun. But not to be ever again, since you really need the critical mass of a dorm to make it happen.

Two! Two more chapters! Hahahahaha!