Wikipedia:Reference desk/Archives/Science/2016 November 8

= November 8 =

Using microwaves or IR to stabilize a compound?
Generally speaking, I tend to think of incoming photons as making a compound more reactive - for example, promoting triplet oxygen to singlet oxygen. But are there cases where, by promoting an electron in an atomic or molecular orbital to a higher level, a compound can actually be made stable against decomposition or other reactions that normally would take place? Wnt (talk) 00:08, 8 November 2016 (UTC)


 * There is a technique called Laser cooling ? That can halt chemical reactions. Might even be able to contain anti-matter in a flask without the whole issue blowing up. --Aspro (talk) 01:07, 8 November 2016 (UTC)


 * That's a good one, but it's not really what I meant. I wasn't looking to cool an ensemble of atoms - what I was wondering is if, say, you could raise the outermost electrons in potassium atoms to a higher energy level and then have them not react immediately with oxygen because, oh, they're "too far out".  yeah, I know, this idea is too far out...  All such examples I think of seem like they should be really unlikely to work, but I don't know there aren't some that would be true. Wnt (talk) 02:05, 8 November 2016 (UTC)
 * This can happen with noble gases to form excimers. An inert gas with an electron elevated to an s orbital looks like an alkali metal, which can can react with halides, or hydrogen. See helium compounds, neon compounds, argon compounds, xenon monochloride and argon fluoride laser for examples. Look for excimer. Even the extremely weakly bonded dihelium can gain quite a strong bond if the molecule is excited. The problem is that these excimers can decay fast.  You are lucky to have something last a second. Normally you would need UV, or electric discharge to excite the electron. Exciting K atoms will get you larger alkali like atoms that would resemble Rb, Cs, Fr, eka-Fr etc. So they are still reactive and not too different.Graeme Bartlett (talk) 08:06, 8 November 2016 (UTC)
 * Rydberg matter is what you get when many of these kind of atoms get together. Triatomic hydrogen is only stable when in an excited state. It resembled a trihydrogen cation with an electron on an orbit around the whole ion. Graeme Bartlett (talk) 08:26, 8 November 2016 (UTC)
 * What about exciting a molecule to a state, which is made more stable by requiring a forbidden transition to return to the reactive state? Plasmic Physics (talk) 10:45, 8 November 2016 (UTC)
 * Actually I think there might be a nucleus like this. In a metastable excited state it does not decay, but if you make it go to the ground state it decays in hours. See Isotopes of tantalum with 180mTa. Also Americium-242m from which you can make mini nuclear weapons. Graeme Bartlett (talk) 11:02, 8 November 2016 (UTC)

Name of condition when one side of the face is tensed
I don't mean that one side of the face has spasms, just that it's extremely tense all the time, involuntarily, the side is raised. The person with this can't even close his mount shout. Obviously it's a medical condition, the face is disfigured. It's like a crooked smile.--Hofhof (talk) 13:22, 8 November 2016 (UTC)
 * It doesn't perfectly fit your description, but I suspect you are talking about Bell's palsy. Looie496 (talk) 14:32, 8 November 2016 (UTC)


 * The more general term is Facial nerve paralysis - for which Bell's palsy is the most common cause, but not the only one. Wymspen (talk) 18:52, 8 November 2016 (UTC)


 * Given the image is entitled "bellspalsy" it seems that the OP has reversed the phenomena. Bell's palsy is the inability to contract the muscles of one side of the face, not the tetanic rictus of the other. μηδείς (talk) 02:37, 9 November 2016 (UTC)


 * Was the image added by the OP - or by Looie496 when he suggested the condition as an answer? Wymspen (talk) 09:26, 9 November 2016 (UTC)


 * I added the image. I think Medeis understood that, though. Looie496 (talk) 14:23, 9 November 2016 (UTC)

Artificial islands near China, earthquake stability
How well will the artificial islands that China is making stand up to an earthquake? I'm sure they thought about it carefully, and the rewards are worth the risks, but I would like to know. thanks. 144.35.45.79 (talk) 17:08, 8 November 2016 (UTC)


 * You might also ask about stability during cyclones and tsunamis. If they laid the foundations on bedrock, their structures would be less likely to be washed away than if they are resting on sand. StuRat (talk) 17:14, 8 November 2016 (UTC)


 * It's sort of a moot point. The function of those islands is to enable China to claim territory in the South China Sea.  Structural stability doesn't have much relevance to that function. Looie496 (talk) 17:36, 8 November 2016 (UTC)


 * I disagree. Temporary structures may not have the same claim as permanent installations. StuRat (talk) 17:59, 8 November 2016 (UTC)
 * The diplomatico-juridic case for recently-built structures is probably very weak in either case. It is more about maintaining a de facto presence. But surely, there is a cost-benefit analysis at the bottom of all this and the budget to maintain the structures is a part of it, so structural stability does matter (since the cost goes up if you need to rebuild everything from scratch every three months vs. twenty years). Tigraan Click here to contact me 18:07, 8 November 2016 (UTC)

Scaling of muscular strength
If a person could grow or shrink in size, maintaining exactly the same proportions, and all other factors apart from size remaining exactly the same, would their muscular strength vary with the square of the linear scale factor? — Preceding unsigned comment added by 109.146.248.86 (talk) 21:05, 8 November 2016 (UTC)


 * There's a problem with the assumption that everything else could remain the same. Larger land animals need to spend a progressively larger portion of their resources just to support their own weight, breath, cool themselves, circulate blood, etc., which leaves fewer resources for everything else.  See square-cube law. StuRat (talk) 21:14, 8 November 2016 (UTC)
 * Why do you have to answer every question with pointless and useless replies? 109.146.248.86 (talk) 21:17, 8 November 2016 (UTC)
 * He cited the relevant article for you to read. I'm not sure what else you wish him to do, since that's all that this desk exists for... -- Jayron 32 21:21, 8 November 2016 (UTC)
 * I partially withdraw my comment since there is indeed a relevant sentence in that article, though it does not fully and explicitly answer the question. My assumption that the reply would be irrelevant was based on the first two sentences and on past experience. 109.146.248.86 (talk) 21:27, 8 November 2016 (UTC)
 * Thanks, you just saved me a bunch of typing. Andy Dingley (talk) 21:46, 8 November 2016 (UTC)


 * The allometric scaling article is more relevant. Though the comparison there between elephant and tiger quoll is impressive, to me it doesn't seem like the tiger quoll is really much different than various mouse skeletons I looked at online, like this deer mouse here. Wnt (talk) 23:32, 8 November 2016 (UTC)


 * From physiological considerations, it seems to me that muscular strength should vary as the cube of body size, not the square. (The contractile force generated by a cubic millimeter of muscle tissue is roughly constant.) Since mass also varies as the cube of body size, the result, applying Newton's formula F=ma, is that animals of all sizes generate similar accelerations.  In other words, a mouse, a human, and an elephant can all jump roughly the same distance. It isn't easy to figure out what the literature says about this issue. Looie496 (talk) 14:46, 9 November 2016 (UTC)
 * This is a thought experiment that neglects all sorts of toher factors, but it's still interesting. This means that if a man can jump two meters, then he can still jump two meters after he has been shrunk, therefore, the smaller man jumps proportionally further, but not absolutely further. -Arch dude (talk) 18:10, 10 November 2016 (UTC)

Radiation and cancer
In a nutshell, if ionizing radiation is a known cause of cancer, how is that it's also used in radiation therapy? Specifically, if ionizing radiation can eliminate cancerous cells, how does it outweigh the risk of getting even more serious cancer? At first glance Radiation_therapy does not clarify this.Thanks.--93.174.25.12 (talk) 21:45, 8 November 2016 (UTC)


 * It's a matter of balancing risks. If the therapy saves life, then the small risk of causing a further cancer is considered worth the risk.  Great care is taken to concentrate the radiation only on the cancerous tissue as far as is possible.  The risk of the cancer spreading is usually a more serious risk than that of causing further cancer.    D b f i r s   21:53, 8 November 2016 (UTC)


 * This is a question that many oncologists have sought to answer. This is a meta-analysis of clinical trials involving over 40,000 women that looks at both the effectiveness of radiation therapy for breast cancer, and the likelihood that the radiation itself kills the patient. It found that even though radiation therapy measurably increases the risk of a number of deadly diseases, the overall survival of patients who received radiation is better than of those who did not. And further, apparently these side effects have been decreasing over time, presumably as newer techniques and technology minimize risk. Someguy1221 (talk) 22:06, 8 November 2016 (UTC)


 * “The risk is considered worth the risk.” I don't think I've seen that construction before. —Tamfang (talk) 17:51, 9 November 2016 (UTC)


 * this source describes a few types of radiation therapy; they have different uses. That said, I've never heard much about the precise frequency/wavelength of the photons used.  It doesn't seem obvious to me that the frequency best suited for killing a cancer cell is the frequency best suited for mutating DNA or for tumor initiation.  For example, high energies can induce a double strand break while much more sedate chemical reactions like thymine dimers from even UV light can lead to the modification of a single base pair. Wnt (talk) 23:43, 8 November 2016 (UTC)


 * Gamma and X-rays are chosen not because they're magic tumor-killers, but because they penetrate very deeply into the body. Someguy1221 (talk) 23:57, 8 November 2016 (UTC)


 * To treat cancer, you must kill cancer cells, which are similar in most ways to the other cells in the body. Therefore, essentially all cancer treatments are harmful to a patient's non-cancerous cells. Better treatments kill cancer cells more selectively, but as yet there are no perfect treatments. This is why chemotherapy has such nasty side effects. For some cancers, radiation is relatively more selective than other treatments. -Arch dude (talk) 01:53, 9 November 2016 (UTC)
 * Discriminating between a normal cell and a cancer cell is hard. But discriminating between killing a cell and causing a carcinogenic mutation doesn't seem obviously impossible, though I'll concede it could be. Wnt (talk) 16:50, 9 November 2016 (UTC)


 * Let me rephrase the OP's question so they can understand the answer "If we know that water is the primary cause of drowning, how can we also use it to cure thirst." If the OP can understand the answer to that question, they can understand the answer to their own.  -- Jayron 32 23:23, 9 November 2016 (UTC)
 * Roger Miller said: "Not enough water puts thirst in a man / And just enough water puts joy in his land / But too much water will overflow / And tear the man's land up - so there you go." ←Baseball Bugs What's up, Doc? carrots→ 00:27, 10 November 2016 (UTC)
 * Or as Paracelsus said: "The dose makes the poison" -- Jayron 32 12:07, 10 November 2016 (UTC)

Orbicularis oculi
Does the palpebral portion of the orbicularis oculi muscle solely run from the medial superiorly to the lateral, or are there fibres inferior to the eye? Le Sanglier des Ardennes (talk) 22:51, 8 November 2016 (UTC)


 * Fibres run both superiorly and inferiorly. There are decent images in the Orbicularis oculi muscle article. This external one is better. -- Flyguy649 talk 18:37, 12 November 2016 (UTC)