Cap'n Refsmmat

Have you any evidence for this?

According to the New York Times article: Incidentally, the Chernobyl accident occurred when they were testing a steam-powered backup system; their generators took a minute or two to kick in, so they planned to use the inertia in the steam turbines to power the pumps in the interim. Unfortunately the test was botched and the reactor went without coolant for far too long.

Another good article on it: http://www.nytimes.com/2011/03/12/world/asia/12nuclear.html?hp It sounds like they've got backup battery power keeping the core cooled, and if they can keep the backup systems working, the reactor will be safe. Apparently they have to release some slightly radioactive steam, but so long as water is being pumped in effectively, there's no reason for the core to have a meltdown.

Yes, I'm aware of this issue. It should be fixed soon. There's a caching system that's not quite bright enough to notice you've changed your avatar and serve the new version to viewers.

Ah, I see. Cache problem. I'll see if I can fix the issue. It should resolve itself eventually, but I need to make it smarter. You don't need to do anything at this point -- I'll fix it and your new photo and avatar will appear.

"Profile photo" is the one displayed only on your profile page. "Avatar" is the one displayed next to your posts. Perhaps you're changing your profile photo instead of your avatar?

We have not deleted anything. Please be sure you press "Add Reply" after composing your response; I don't know any other reason why a post might not appear.

The trouble is that the program runs and terminates, and Dev-C++ closes its window as soon as the program terminates. You can try using any C++ command that requires user input, like cin.get() or getchar() or whatever stdio might use. That'll force the program to wait for you to press enter before closing.

Here's the way we thought of it in my electricity & magnetism course: In an insulator, any charge you give it is trapped. You can deposit electrons on the surface of the insulator, giving it a negative charge, but those electrons will stay in a fixed location, and they will not conduct through the insulator to another location. However, if you put a wire on the surface of the insulator, the electrons there at the surface may be conducted out through the wire. The electrons not in contact with the wire, however, will be unable to move and will stay on the insulator. Of course, in practice electrons with sufficient energy can move around if they want to, just with some difficulty, and so some electrons will move through the insulator. It's just that conductors make this far easier.

The reason that classical circuit analysis treats electricity as moving positive charges is because they didn't know what electricity really was. It turns out that in the mathematics, though, an electron moving one way is the same as a positive charge moving the other way, even if there's no physical meaning to saying positive charges are moving in a conductor. So positive charges aren't moving over wires. Rather, negative charges move the opposite direction. The moving positive charges are really just a lack of negative charges. If I move a lot of negative charges to one end of a wire, it becomes more negatively charged, and the other end becomes more positively charged, in exactly the same way as what would happen if I moved positive charges the opposite way. Just think about things solely as electron motion and it should work out. Right, and the "positive charge" in the fur is just caused by a lack of electrons, not a gain in protons. The key is that insulators are not perfect. Some charge will "leak" despite your best efforts. Humid air even conducts, very slightly.

Pro tip: If you see one person making multiple spam posts, you only need to report the first one, perhaps with a comment saying "there's a bunch more." We have a button that deletes all of them simultaneously, so reporting multiples just makes us read more reports.

Stop thinking of the electron and photon like particles that can easily collide; it's just confusing you. Nuclei have different excited states that photons can excite; I'm not certain of the details, as I'm not an atomic physicist.

What improbable states? By "transmitted," I mean the photon passes by without interacting with the electron.

This is why materials can be transparent to certain wavelengths of light. If the electrons cannot accept that amount of energy exactly, then the light is either reflected or transmitted.

soundoflight, please see rules 5 and 10.

It doesn't get absorbed by the electron.

I have, very rarely, gotten confused emails from someone who posted a link in their first post and got spam-banned. It can be very difficult to tell the difference, unless they're linking to sites selling Viagra and porn.

So far, I've restricted members to having signatures only after 10 posts. Particularly devious spammers would make a completely innocuous post, wait a couple weeks, and then add links to their signature, so that nobody would notice the links and they could sit for months. I've also restricted the number of PMs sent by new members, since some spammers just PMed spam to everyone. It's also possible to do a flood limit and limit them to a certain number of posts per day; that would slow down the ones that want to make as many spam posts as possible, but it's not particularly helpful as we can delete all of the posts with one "Flag As Spammer" button. I could, hypothetically, ban new members from using links altogether, although that would be trickier, and would be very inconvenient for the non-spammer members. Looks like this only applies to members with less than thirty posts. I'm not sure that's intentional.

Could you elaborate?

Why can't both be true? Some traits come from common ancestry, some come from convergence. It's perfectly plausible.

I'm not sure I get what you're aiming at here. Could you elaborate?

The problem stipulates "where c = a + b". hkus10: Yes. And a + b = c, so the upper-right cell is equivalent to c. Not 2c.

The question of whether it has antecedent causes is exactly what I mean is not physics. Sure, they repel due to the electromagnetic force, but how does that actually work?

You've made an error in that upper-right matrix element, then.

Yes, that'd work. You can start with: [math]a \begin{pmatrix}1 & 0 & 1\\ 1 & 0 & 0\end{pmatrix} + b \begin{pmatrix}0 & 1 & 1\\ 0 & 0 & 0\end{pmatrix}[/math] and see where that leads you.