Wikipedia:Reference desk/Archives/Science/2012 October 21

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October 21

Thermionic emission

Our article on Thermionic emission states that

Guthrie discovered that a red-hot iron sphere with a positive charge would lose its charge (by somehow discharging it into air). He also found that this did not happen if the sphere had a negative charge.[1]

I would expect this to be just the opposite, so I asked at Talk:Thermionic emission#Why lose positive charge? Please reply there. Thanks! — Sebastian 14:25, 21 October 2012 (UTC)

Ultra-dense deuterium, Rydberg matter, cold fusion, etc.

Our article on Rydberg matter is just incredible, and looks well supported by sources - giant atoms at highly excited states which intermingle, which seems pretty similar to saying, a bunch of positively charged ions knocking around in a cloud of extremely high energy electrons.

But it was proposed for deletion by people claiming it was fringe matter, and following this, I find that the author was (apparently) one of the researchers involved in somehow collapsing this stuff to make ultra-dense deuterium, an article since redirected because the idea is absurd - stuff with a density of 140 kg/cm³. Apparently it is a "quantized line vortex" (a phrase surely destined for sci-fi glory!) of deuterons acting as bosons in a condensate. (Bose-Einstein condensate I assume?). Someone in Reno even proposed it as an explanation for how cold fusion works. [1] But apart from that last, the papers were coming out of one group in Sweden, of which our User:Holmlid was a member. Fortunately trees are scarce in the virtual world or I do believe our deletionist friends would have nailed him to a ruddy cross; in any case he was successfully beaten off and hasn't edited WP since.

However, I see that the one group made many publications, and now there is now a different group discussing this stuff seriously [2]. Now mind you, my own level of competence is such that I don't even understand why a Bose-Einstein condensate isn't prone to undergo fusion, if it isn't. I don't know if this is a good journal, though Journal of High Energy Physics cites an impact factor of 5.8, which in biology I know is very respectable. So I'd like to restore an article on ultra dense deuterium, but I could surely use some encouragement and more eyes on the topic.

Besides, this is just about the coolest thing I've found on Wikipedia all year. Wnt (talk) 16:53, 21 October 2012 (UTC)

Your question, I gather, is whether "ultra dense deuterium" is a sufficiently notable subject to justify a freestanding article. Looie496 (talk) 17:20, 21 October 2012 (UTC)

Hmmm, not precisely. The WP mechanics are something I can decide on my own (unless someone beats me to it!) - what I'm really interested in is more the issue forbidden to proper WP editing consideration, namely, are these observations actually real and true? Today I learned about two different kinds of electron-bound "matter" with lower and higher densities than I'd ever heard of, unless it's all bogus. But whether they are supported by good publications is the most accessible surrogate for that. Wnt (talk) 17:26, 21 October 2012 (UTC)

You could get this sort of density by high pressure. Another way is extreme magnetic fields, in which case you get long chains of atoms stretched along the magnetic field lines. Also note that the content was merged and not just axed, appearing at deuterium#Ultradense deuterium Graeme Bartlett (talk) 10:00, 22 October 2012 (UTC)

Sorry - you're absolutely right. Wnt (talk) 17:41, 22 October 2012 (UTC)

Edible fungus

“ 'Forty-two pounds of edible fungus

In the wilderness a-growin

”

This is a borderline Language Desk question, but on balance I decided to ask it here. I notice that edible fungus redirects to edible mushroom. Is it really the case that every edible fungus is a mushroom? I tend to think of mushrooms as fungi that have a well-defined "head". --Trovatore (talk) 22:12, 21 October 2012 (UTC)

How about truffles ? Our article calls them a "subterranean mushroom", but that's not what I think of as a 'shroom. StuRat (talk) 22:29, 21 October 2012 (UTC)

How about yeast? —Tamfang (talk) 23:00, 21 October 2012 (UTC)

It probably is more of a language question. I dare say that edible fungus is probably the more technically correct term, but edible mushroom would be the term used and understood by 99% of the english speaking world. Cloud ear fungus is another one which I would struggle to call a mushroom, but the article says it is known as black Chinese fungus (or mushroom).. There is also a difference between culinary terms and strict botanical terms, such as fruit and berry have quite different meanings in culinary use as opposed to botanical use. Vespine (talk) 00:24, 22 October 2012 (UTC)

Cheeses contain edible fungi: Penicillium roqueforti is used in Roquefort blue cheese, and Penicillium candidum is used in making Brie and Camembert cheeses. --Jayron32 01:00, 22 October 2012 (UTC)

Aspergillus oryzae is used in the fermentation of various Chinese and Japanese foodstuffs. --Jayron32 01:02, 22 October 2012 (UTC)

Quorn is a popular food made from edible fungus, but members of Ascomycota are not usually considered mushrooms (e.g. fusarium species grow in your sink drain). The man ingredient is labeled as a mycoprotein. So, no: not every edible fungus is a mushroom, but note that mushroom is is a common term with no taxonomic weight, and usage will vary. SemanticMantis (talk) 01:03, 22 October 2012 (UTC)

("Mushroom" is sort of like "bug." Both are common names that are essentially ill-defined, but the terms also can carry taxonomic meaning in the right context, as in true bugs. ) SemanticMantis (talk) 01:06, 22 October 2012 (UTC)

So I wasn't really talking about molds. I'm thinking of things like white fungus soup, where the fungus is macroscopic but doesn't seem mushroomy to me. --Trovatore (talk) 02:50, 22 October 2012 (UTC)

Are there any fungi that are not even remotely mushroom-like but are eaten whole as the food itself? As in, the food is neither a fungal extract nor a fungus mixed with many other things. I rather enjoy cooked mushrooms, but I'd never eat a fistful of yeast. Someguy1221 (talk) 02:46, 22 October 2012 (UTC)

How about just the "blue" with no cheese?GeeBIGS (talk) 02:52, 22 October 2012 (UTC)

Again, I'm not interested in molds. --Trovatore (talk) 02:56, 22 October 2012 (UTC)

Why aren't you interested in molds? You asked for edible fungi that aren't mushrooms. Molds are clearly fungi and clearly not mushrooms (i.e. no one would classify a mold as a mushroom, and everyone classifies them as fungi), and many are quite edible. You're changing the rules in the middle of the game. --Jayron32 04:45, 22 October 2012 (UTC)

Molds are maybe fungi in the same sense that tomatoes are fruit. They aren't fungi in the everyday understanding of the term. --Trovatore (talk) 07:05, 22 October 2012 (UTC)

Huh? I've seriously never heard that proposed that way. Molds clearly belong to the fungus branch of the tree of life, and in my entire living memory, I've never heard anyone propose that they didn't. Seriously, if molds aren't fungi, what are they?!? --Jayron32 22:53, 22 October 2012 (UTC)

They're molds.

Look, I agree, biologically, they're fungi. But the common usage of the term fungus does not really encompass molds, or yeasts either, except perhaps when you're talking about fungal infections. --Trovatore (talk) 22:57, 22 October 2012 (UTC)

OK, then we're going to have to agree to disagree then; what it sounds like you are proposing to me sounds like (subbing out words) "the term mammals does not really encompass cats, or dogs either". I've never considered that anyone wouldn't think that "mold" was a subset of "fungus" or that they occupied mutually exclusive categories in any way. Clearly you do, and clearly I don't. Neither of our feelings on this are apparently self-evident, just as you've never heard anyone consider a mold a fungus, I have never heard anyone who didn't, on any level, either colloquially or technically. It sounds, to me, like someone claiming that cardinal is not a shade of red or that trees are not plants. --Jayron32 16:55, 24 October 2012 (UTC)

You mention yeast. The term brewer's yeast is often used to indicate yeast taken as a dietary supplement, which is pretty much "just yeast", if I'm not mistaken. In fact, we have the article Nutritional yeast. I know that you said no extracts, but there's always vegimite, which is more or less pure fungus, though the cells themselves have been disrupted. Buddy431 (talk) 04:36, 22 October 2012 (UTC)

It looks like you're responding to Someguy1221, who seems to be taking much the same tack I had in mind. Edible fungus you might find 42 pounds of in the wilderness a-growin', but not mushrooms. Something like the snow ear fungus used in white fungus soup, for which our article gives as an alternative name the "white jelly mushroom", but which it seems unlikely anyone would call a "mushroom" if they found it while walking in the woods. Or our article on Trametes versicolor calls it a "mushroom" repeatedly, but it sure doesn't look like a mushroom to me. Are these really "mushrooms"? Is there any clear demarcation that makes them such, in opposition to common usage? --Trovatore (talk) 07:41, 22 October 2012 (UTC)

Yes, the clear demarcation that makes the Trametes fungus a mushroom is that they are Agaricomycetes these are also known as "bracket fungus", or "bracket mushrooms". Our article mushroom explains that this order, as well as Basidiomycota, is what is usually meant by "mushroom". The example I gave above is from the Ascomycota, which is not usually considered a mushroom order taxonomically, but some members are considered mushrooms for culinary purposes. Some of the key features of a "classic" mushroom are the stipe and the pileus. But this has really just gotten into folk taxonomy at this point, if you want to say that fungi molds are not fungus. Also, I invite you to reconsider the plausibility of a 42-pound haul of mushrooms. Just this year, a hunter told me of his (albeit lifetime record) 60 pound haul of morels. SemanticMantis (talk) 13:00, 22 October 2012 (UTC)

I'm confused — are you saying I said it was implausible? I don't see where. (The forty-two pounds thing is a literary allusion, BTW.) --Trovatore (talk) 22:44, 22 October 2012 (UTC)

Yes, when you said "Edible fungus you might find 42 pounds of in the wilderness a-growin', but not mushrooms." -- I thought you were questioning the plausibility of finding 42 pounds of mushrooms growing in the wilderness. It seems I was mistaken, but it looks like you have plenty of good answers here: to sum up: no, not all edible fungi are mushrooms :) SemanticMantis (talk) 15:12, 23 October 2012 (UTC)

Arg. The most recognizable mushroom on Earth, and I never, ever see them. Not even the false ones. I wish I knew his secret... Wnt (talk) 17:45, 22 October 2012 (UTC)

Corn smut - not a mushroom, some consider it edible in more or less unaltered form. Besides it is such a fun word. Rmhermen (talk) 16:14, 22 October 2012 (UTC)

For all of you who didn't pick up on it — the 42-pounds quote at the top of this thread is a quote from Homer Price, a work of fiction. Nyttend (talk) 12:04, 24 October 2012 (UTC)