Wikipedia:Reference desk/Archives/Science/2016 January 28

= January 28 =

Acquired resistance to diseases such as Zika virus
When a person becomes infected with Zika virus, they get mildly sick, then they recover. Presumably this is because some response to the disease occurred in the body which took away the virus's ability to make the person sick. What is the nature of this immune response? How long does it last? In other words, if one got dengue fever, yellow fever, west nile, or zika (all somewhat related viruses per the article) could they catch the same strain of the same disease the next week? Or does the previous infection and recovery provide some immunity for some period of time? If the latter is so, then why can't a vaccine or immunization be devised? Has there been any discussion of women letting themselves get Zika when non-pregnant so that the next year they could have a baby who was not microcephalic despite exposure to mosquitoes carrying the virus? The worry seems to be so great that some Central American governments are advising women not to have babies for some unspecified period of time, during which time the governments plan the dubious goal of eliminating mosquitoes of the sort which are vectors. In the US midwest, governments have ineffectually spent a lot of money for years trying to get rid of mosquitoes which transmit the related west nile. Edison (talk) 04:32, 28 January 2016 (UTC)


 * Acquired immunity takes a while after infection to develop. As for your other questions, the general answer is "it depends". Some pathogens tend to not change very much. Smallpox is such a pathogen, which is why we were able to eradicate it: one vaccination and you're immune to all forms of it. Other pathogens vary widely. Influenza is a virus which changes epitopes very frequently, which is why there is no universal vaccine and they make a new vaccine every year. This is simply evolution in action: pathogens are constantly adapting to their hosts so they can reproduce and spread more effectively. Note also that creating vaccines is as much of an art as a science. There is a lot of trial-and-error that goes into vaccine development. And some pathogens are just not good targets for vaccination. Malaria is one example; the malarial parasites "hide" inside liver and blood cells most of the time, which shields them from the immune system. --71.119.131.184 (talk) 04:51, 28 January 2016 (UTC)
 * OK, then, to focus in: does Zika change its form like influenza, or is it pretty constant like smallpox? And how long does the acquired immunity last? Have individuals been infected by Zika multiple times? Edison (talk) 05:11, 28 January 2016 (UTC)


 * For the most part, no one knows for sure. Zika, though not exactly new, wasn't seen as very significant until recently.  Consequently, it hasn't been studied very much.  Zika is an RNA virus, like Influenza, and as a class RNA viruses are more prone to mutation than DNA viruses like smallpox.  However, being an RNA virus is only part of the story in determining variability and resistance to vaccines.  Polio is also caused by an RNA virus, but nearly eliminated due to vaccine efforts.  By contrast, flu vaccines provide only seasonal resistance, and efforts to develop an HIV vaccine have largely failed so far.   Zika is a relative of dengue.  There is currently no vaccine for dengue, but dengue vaccine development is considered "promising" .  Acquired immunity to dengue appears to have long-term persistence; however, there are four major variants of dengue virus, and acquired immunity apparently only provides protection against viruses of the same type.  It is generally expected that acquired immunity to Zika will prove persistent, but it is too early to know for sure.  Dragons flight (talk) 09:04, 28 January 2016 (UTC)


 * I think the reason that Zika hasn't been well-studied is not so much that it's "new" it's that the recent large outbreak seems to be causing this horrible microcephaly birth defect. Zika outbreaks were noted as far back as 2007 but were not considered important.  In the past, that connection to microcephaly either didn't happen or was sufficiently rare that nobody noticed it.  Aside from the birth defect, Zika causes a very mild flu-like disease - and it's symptomless in 60% to 80% of those infected.  There are literally dozens of similar viruses in those parts of the world that spread in similar ways and produce similar flu-like symptoms.  A disease that's that innocuous simply doesn't gather a ton of research funding.  It's still far from certain that it is the cause of the microcephaly outbreak - but now it's suddenly in the spotlight - so only now is science being brought in to deal with the problem. SteveBaker (talk) 13:32, 28 January 2016 (UTC)


 * I don't think it's exactly true that flu vaccines are only seasonal. Rather the virus change fast enough that no two seasons are identical.  There is evidence that those exposed to the pandemic Spanish flu fared better than those that weren't exposed during a recent bird flu outbreak.  The mortality data had pre/post spanish flu step changes that led scientist to believe that older people that survived Spanish Flu fared better than younger people that weren't born until after the pandemic.  As for Zika, think of West Nile virus except transmission route is more difficult as it is only human-to-human through the mosquito.  West Nile virus has both human and avian hosts.  --DHeyward (talk) 07:52, 29 January 2016 (UTC)


 * Optimal_virulence is highly relevant when considering acquired resistance and viral mutation, and also speaks to why Zika might not have been a big problem in the past. The Red Queen hypothesis also comes in to play. One thing that is interesting is that acquired resistance of a mother can be passed on to a child via maternal immunity AKA passive immunity. For some pathogens/diseases e.g. measles, a vaccine given to the mother can confer a period of resistance to the foetus/infant child . SemanticMantis (talk) 15:28, 28 January 2016 (UTC)


 * For "How long does it last?" specifically, the answer is that it varies widely, depending method of acquirement (e.g. infection or vaccine, type of vaccine, maternal immunity etc.), and on pathogen. Here's a paper that discusses the duration for pertussis . In epidemiology, this refractory period is very important. SIR models make the assumption that immunity lasts forever, but SIRS models close the loop. So searching /SIRS model [disease]/ will get you to estimates of immunity persistence for diseases of interest. SemanticMantis (talk) 15:36, 28 January 2016 (UTC)


 * I was going to ask the same question myself a couple of times this week, but I think a lot is just not known. We only recently learned that Ebola can lurk in semen months after we thought the patient was cured, for example - so who would want to go out on TV and tell women to go ahead and catch Zika, get over it, get pregnant, and see if it can hang around and infect the fetus later on?  We'd have to see data on women who had Zika and then became pregnant, and I'm not sure it's out yet, especially as there's no commercial test for it.  This is just about the state of the art, such as it is, and it pretty much deliberately skirts the issue... part of the reason though is it's just not saying to do anything in particular, except try to figure out what happened for scientific reasons. Wnt (talk) 16:27, 28 January 2016 (UTC)
 * This is nearly pure OR (well I have heard some RS mention immunity) so I haven't mentioned it yet, but one thing which hasn't really been mentioned yet is the question of why the recent epidemics. Not just the South & Central American one but the Pacific Island one as well. The virus has been present in parts of Africa and SEA for many years. Is it just because of the global advanced in healthcare & monitoring of diseases combined with the links to microcephaly and GBS? Perhaps with some degree of randomness/bad luck I'm not certain about Africa, but as far as I know the vectors are fairly widespread in SEA hence dengue fever outbreaks aren't that uncommon. Has there been a mutation increasing virulance or the effects of infections? Or is it possible that zika is actually fairly endemic to the parts of Africa and SEA where it's present and quite a few people get it, perhaps many of them when they are young. But due the the lack of clustering and some degree of herd immunity, you don't get epidemics. And perhaps likewise the side effects are harder to detect plus as mentioned people may be more likely to get it before pregnancy (at least for microcephaly, not sure about GBS). Whereas in the places with recent outbreaks, because it's new few people had immunity so it's now spreading through the population quickly hence the epidemic. An interesting point is that if I understood our articles correctly when I read them a few days ago, it sounds like some researchers are thinking the epidemic in the Americas came from the Pacific Island epidemic. I'm not sure if they did any genetic-evolutionary examination. If they didn't and while I would presume epidemiologists know what they are doing, I wonder how well they've considered the possibility despite the lack of any known outbreaks, the frequency in SEA and Africa could be high enough to be the source. Nil Einne (talk) 11:09, 29 January 2016 (UTC)


 * "Why the recent epidemics?" is a good question for many viruses, answerable by "cheaper and easier international travel" and "intrusion of humans into new biomes." Zika was confined to a narrow geographic belt in Africa and Asia, and rare in humans from its discovery in 1952 until 2007, when it occurred in the island of Yap in the Federated States of Micronesia, then spread through Polynesia, New Caledonia, the Cook Islands, and Easter Island.  From there, it has spread through South and Central America, and is expected to spread through Mexico into the Southern United States.


 * What caused the sudden geographical spread of the Zika virus? The most likely answer is "cheap travel."  "Patient zero" in this series of outbreaks was likely someone who traveled from the Zika virus's endemic zone to Yap.  Air travel being cheaper than it's ever been, worldwide (in inflation-adjusted terms), the likelihood it would hop islands from Micronesia to Easter Island (off the coast of Chile), and from there through Latin America is greater than it's ever been in human history.


 * Just as SARS spread from infected poultry to humans in China, then spread worldwide on passenger aircraft, and the same way influenza spread from (probably) a hog farm in Kansas world wide, to mutate every few years and sicken and kill millions - because World War I caused the movement of people across America, and from there, across the world to an unprecedented extent, diseases called zoonoses will spread from animals to become new diseases in us. And it's likely that Zika, first isolated from a monkey, is just such a zoonosis, and spread from monkeys to humans.


 * What caused the drastically increased number of patients falling ill with Zika? Probably the fact that where Zika comes from, the people who would fall ill from Zika fell ill enough so that they either died or were somehow not as successful in breeding as other people, very long ago, and those people genetically better suited to either not being ill with Zika at all or only developing a minor, self-limiting infection populated areas where there is a lot of Zika virus.


 * Inherited, genetically transmissible immunity (for example, not having the gene for one particular cell membrane protein to function in T-cells - or having a copy of the gene for sickle cell disease) is actually a limiting factor in the transmissibility of several diseases, such as malaria,  plague, AIDS, Ebola and even new variant Creutzfeld-Jacob Disease, also known as "Mad Cow Disease".  Move the Zika virus where this natural selection for resistance to it hasn't occurred, and more people get ill with it, and may be more profoundly affected (such as the microcephaly in infants whose mothers contract Zika during pregnancy).


 * We'll see more and more of these unfamiliar viruses as people (a) move deeper into rain forests and other primeval habitats, become exposed to "emerging viruses," then (b) travel back to civilization and spread these viruses around to people who weren't selected by Nature to tolerate them.


 * Richard Preston, author of The Hot Zone, a nonfiction account of the Ebola Reston virus outbreak in a suburb of Washington, DC remarked that if the HIV virus had been named for where it was first seen or known to have spread from (as many viruses are), the "Kinshasa Highway" virus would have been a reasonable name for it, as that road provides a direct path for those infected with HIV from, say, eating infected wildlife from the dense forests of Central Africa to travel quickly across Africa, so that HIV can pop up far from where its animal hosts live, and spread by sexual contact between those infectees and, say, prostitutes who ply their trade on that highway. loupgarous (talk) 08:04, 31 January 2016 (UTC)


 * This is a widely disseminated idea, but one which I receive with increasing skepticism. HIV is transmitted in a very personal way, and the speed of its spread is the speed of sex.  Whether it spread within Africa for a while longer or moved to Haiti and San Francisco is a kinetic effect - an important one, to be sure, for the people in "And The Band Played On", but for its spread abroad a single doubling of the number infected in Africa works just as well as a doubling in intercontinental travel.  And it doubled there many, many times after it became known to science.  So I wouldn't blame the highway - I would blame King Leopold, however.  One aspect of the history that the vapid mass-media talk of bush meat ignores is that for years the Belgian Congo was under direct government by a corporation, with the natives under quotas where if they failed to collect enough rubber they were supposed to turn over severed hands instead.  (Even in recent memory Liberians were getting the choice of "long sleeves or short sleeves"...)  As a result you had desperate starving people around, cutting rubber vines, killing, butchering, and eating anything they could find, and cutting off hands with the same un-sterilized machetes.  Now mind you, that is not an established theory but just a Refdesk rant that doubtless can be held up as one of the things wrong with this free-ranging conversation... still, that's where it came from. Wnt (talk) 13:29, 31 January 2016 (UTC)

East Asia and Stroke
How come East-Asian countries are more affected by stroke compared to the rest of the world? Is it genetics or is it diet related?

Has there been any studies on second-generation, third-generation, etc, East-Asian immigrants to western countries to see if the change in diet reduces the rate of incidence of stroke? Johnson&#38;Johnson&#38;Son (talk) 05:05, 28 January 2016 (UTC)


 * One possible reason is if they are less affected by other diseases. Everyone has to die from something, so if they have fewer deaths from cancer, heart disease, and diabetes, that would automatically mean more deaths from everything else, including strokes.  Put another way, many of the same people who had strokes would have died earlier, of another disease, had they lived in the US and eaten a US diet, never having lived long enough to have a stroke.   StuRat (talk) 05:38, 28 January 2016 (UTC)


 * Stroke rates are significantly increased in countries with bad air pollution, such as China and Indonesia. It is still predominantly a disease of older people, but accentuated by the poor air quality in many parts of Asia.  India, which has worse air than China, has a younger population with higher rates of death due to diarrhea and other acquired diseases.  If people are dying young due to infectious diseases, then they aren't dying of stroke in old age, which is one of the differences.  Once one has access to decent health care and sanitation to reduce the rates of acquired diseases, then environmental and lifestyle factors become important.  Only after one controls for the large differences in environment and lifestyle is one likely to see the impact of genetics.  Dragons flight (talk) 08:45, 28 January 2016 (UTC)
 * That explains China, but AFAIK Japan and South Korea has excellent air quality. Johnson&#38;Johnson&#38;Son (talk) 09:14, 28 January 2016 (UTC)
 * South Korea also has an air quality problem partly due to wind transport from China, though not as bad as China. Japan does have pretty good air quality, but they may be something of a special case.  Their population has the third highest average age in the world, and significantly higher than most of Asia, which is going to make diseases typical of old age more common in Japan.  Dragons flight (talk) 09:25, 28 January 2016 (UTC)

I think this is where methodology and statistics are needed. It would be hard to distinguish ischemic stroke death from death from heart disease since they play off each other. I think the biggest takeaway is stroke and heart disease are first world robbers. Other diseases are more significant in non-first world countries. A person with clogged arteries that has atrial fibrillation that leads to a blood clot that travels to brain and dies - what does that mean for the stat? Heart disease or Ischemic stroke? They are too closely related to make a meaningful guess. "He's dead Jim" is as good as any.

What if we could eradicate the bad mosquitoes?
If we could and did eradicate harmful mosquitoes, would we end up regretting it? Do they have useful predators, or do they serve other benefits we need?? (I do understand that there are thousands of mosquito species.)Hayttom (talk) 18:40, 28 January 2016 (UTC)


 * Skeeters are definitely a part of the food chain, for dragonflies, birds, etc. DDT was tried, and it was effective in its way, but it had bad side effects on the environment. ←Baseball Bugs What's up, Doc? carrots→ 18:45, 28 January 2016 (UTC)


 * A more subtle approach is being tried, since the females need blood only after mating. The strain Aedes aegypti OX513A is short-lived and offspring will die before biting age.  See the Oxitec solution.    D b f i r s   19:02, 28 January 2016 (UTC)


 * Being part of the food chain isn't itself a problem. The question is, are they an irreplaceable part of the food chain ?  That is, would other insects/animals fill their niche (except for the blood-sucking part) ?  Or, even if nothing does, are there any predators of mosquitoes which are solely dependent on them ?  If not, then hopefully those predators would survive, although their numbers might decrease.  StuRat (talk) 19:10, 28 January 2016 (UTC)


 * Actually, the scaremongering of DDT killed way more people, through malaria and other disease, than the chemical ever could and environmental damage is manageable. Fear of DDT and fear of nuclear power are my "bad science coupled with overwhelming PR = dangerous policy" pet peeves.  --DHeyward (talk) 08:30, 29 January 2016 (UTC)


 * The impacts of such an eradication cannot be predicted with much confidence. But some scientists think that it would be OK to eradicate mosquitoes, meaning with very little alteration to non-mosquito biodiversity, or overall ecosystem function and ecosystem services. Here's the related article in Nature . Basically, thinking goes like this: ecological niches can be filled by other organisms with similar functional types. As competition from mosquitoes went down, other freshwater insect larvae would do better, and the fish that eat little bugs are just as happy to munch on other larvae. There might be more problems in the arctic, and many plant species would lose their current pollinators (these are both covered in the Nature blurb).
 * Rather than use broad spectrum pesticides like DDT, people are currently researching the ethics, legality, and science of various other techniques that are far more selective, and in principle can kill only mosquitoes. See Mosquito_control for an overview. Sterile_insect_techniques, combined with gene drives (nice FAQ from Harvard here ) could (theoretically, in principle) eradicate mosquitoes and only mosquitoes from Earth. Another possibility is a biological control agent such as a virus that kills mosquitoes but does not infect other insects . As I said at the start, this is still uncertain. Some experts think there wouldn't too many problems, while other experts would still urge caution. Here's a video of another entomologist on the issue of mosquito eradication. Ecology is a very tough field, and is in some ways still in its infancy, since there's very little we can predict with much confidence about any eradication or introduction of species. SemanticMantis (talk) 19:21, 28 January 2016 (UTC)
 * The most harmful mosquitoes are, in fact, sort of "domestic animals". For instance, Aedes aegypti is uniquely adopted to inhabit human settlements and is not found far from them. It's eradication will have no impact on the wild life. See this. Ruslik_ Zero  20:13, 28 January 2016 (UTC)
 * That's a very good point. Here's a scholarly review article on the domestication/ evolution of human commensalism in A. aegypti . SemanticMantis (talk) 22:39, 28 January 2016 (UTC)

Here is an interesting article on the subject: Would it be wrong to eradicate mosquitoes? Richerman    (talk) 22:40, 28 January 2016 (UTC)


 * It's definitely a risky step. If there's one thing we've learned about this kind of thing is that the deep consequences of these kinds of decision are very hard to know in advance.  That said, there isn't a need to eradicate all mosquitos.  There are species that don't bite humans or that don't transmit any known diseases that we can happily leave alone.  Done carefully, it might be possible to eradicate the bad mosquitos and let the good ones expand to fill the ecological gap that results.  But whether there is some unforseen consequence that starts a domino slide of events into a major problem...well, we really don't know.


 * To pick an example - if mosquito-born diseases kill close to a million humans per year - then eradicating them will cause population growth in parts of the world that may not be able to support that growth. That might just mean that more people die of starvation than previously died of malaria - but you just don't know what other consequences that might have.


 * That said - we are annihilating other species more or less by accident all the time. List of recently extinct animals, List of recently extinct mammals and List of recently extinct birds gives some idea of the scale of this for larger, more noticeable organisms - so will the deliberate extinction of a handful of mosquito species be any worse?


 * SteveBaker (talk) 16:47, 30 January 2016 (UTC)
 * There are species of mosquitos that don't bite people? Can they spread mad cow disease? 75.166.29.132 (talk) 15:56, 31 January 2016 (UTC)
 * There are species of mosquitos that don't bite people? -- Yes, according to our mosquito article: "Many species of mosquitoes are not blood eaters and of those that are, many create a "high to low pressure" in the blood to obtain it and do not transmit disease. Also, in the bloodsucking species, only the females suck blood. Furthermore, even among mosquitoes that do carry important diseases, neither all species of mosquitoes, nor all strains of a given species transmit the same kinds of diseases, nor do they all transmit the diseases under the same circumstances;"...and..."Over 3,500 species of mosquitoes have already been described... Some mosquitoes that bite humans routinely act as vectors for a number of infectious diseases... Others that do not routinely bite humans, but are the vectors for animal diseases".
 * Can they spread mad cow disease? - Unlikely. The "prions" (which are mis-folded proteins, not bacteria or viruses) that cause "mad cow" disease (and Creutzfeldt–Jakob disease in humans) are concentrated in nervous tissue - and very, very little is in the blood.  I don't think there has ever been a case of the disease that wasn't traced to either: (a) the consumption of nervous tissue from an infected animal or (b) medical procedures such as blood transfusion from an infected human.  I suppose it's not entirely impossible for a mosquito to transfer enough prions in blood-to-blood transfer,  it's sufficiently improbable that no cases have yet been attributed to this route.
 * The thing about most of the diseases that mosquitos transmit is that the mosquito itself is allowing the disease agent to replicate. But with Creutzfeldt–Jakob, it's not likely that the prions would be replicated inside the mosquito.
 * SteveBaker (talk) 16:55, 31 January 2016 (UTC)
 * There's actually a lack of consensus on what the lowest infective dose of prions is, as a recent experimental study indicates. When the only source of human growth hormone was from pituitary glands harvested from cadavers, a 2013 letter to the CDC's Emerging Infectious Disease Journal reviewing the available literature on iatrogenic Creutzfeld-Jakob disease states over 226 cases of iatrogenic Cretuzfeld-Jacob disease, invariably fatal, resulted from the use of this source of human growth hormone. (Readers, please know that the use of human pituitary gland-derived human growth hormone stopped in the 1980s as pure, uninfected human growth hormone made from recombinant DNA techniques became available, so you can't catch CJD from injections of human growth hormone these days).


 * Given that "old variant" Creutzfeld-Jakob disease is sporadic and rare, even the fact that most pituitary glands were probably harvested from cadavers of people who had had some neurological complaint argues strongly that injection of what were probably small amounts of the prion which causes CJD through the peripheral circulation (HgH is injected into the muscle) killed 226 people who'd had those injections. Given that work in the mouse model (which I cited above) doesn't identify a threshhold prion dosage below which no infectious prion disease occurs, we can't rule out transfer of prions through insect bites. loupgarous (talk) 19:05, 1 February 2016 (UTC)

physiology
why are potassium ion channels slow to open and close compared to sodium ion channel? — Preceding unsigned comment added by 117.102.36.38 (talk) 18:55, 28 January 2016 (UTC)
 * Are you asking what function that serves or what physical mechanism causes it to happen? Looie496 (talk) 18:58, 28 January 2016 (UTC)

Mounting with adhesive
When mounting a solid light-weight cube with adhesive, is it more likely to stay attached if adhered to a wall or to the ceiling (assuming the same amount of adhesive either way)? My instinct is that the ceiling might well provide a more durable connection because torquing against the wall might aid in peeling the object off the wall, but I'm not really sure. Dragons flight (talk) 19:08, 28 January 2016 (UTC)


 * Wow! This is a tough one to answer without using calculus!  I think you're going to have to integrate the normal force at all points of contact to determine the net torque, which is coupled right back in as another force, superpositioned on top of the normal force, to provide a net normal force at all points.  You're going to need a model for the rigidity of the cube, an approximation for its fulcrum (presumably the lower edge, but maybe not!), and a valid model for the net force of adhesion provided by the adhesive, as a function of normal force, contact area, and so on.  If you really want to make your life difficult, you'll have to account for shear force, too!
 * To the extent to which you can neglect these horrible details, the adhesive on the wall is working against the shear, and against the weight in the ceiling case. If the adhesive is uniform and behaves isotropically, (which is probably a terrible approximation), then you can solve for which scenario gives you better margin against adhesive failure.  You need a detailed, robust, and valid model of the adhesive to answer this subset of the question.  (That involves a bunch of awful tensor math!)
 * I bet you're going to have to use an engineering approximation, or empirical data, to get a useful answer. Adhesion is one of those un-sung areas of physics where the math is arguably harder than the mathematics in general relativity, but doesn't get popularized in science museums.
 * Besides, we have an easy alternative: we can simply test the behavior for a specific adhesive!
 * Nimur (talk) 19:12, 28 January 2016 (UTC)


 * I don't need to write a dissertation on the topic. Experimental evidence would be fine.  However, it feels like the kind of experiment that has certainly been done before, so I was hoping there might already be a general answer that one or the other orientation is typically more resistance to failure.  Ultimately, given the low mass and large contact area, I rather suspect that either orientation would be fine.   Though, since I can't know that for sure, I would prefer to go with whichever option gives the greatest likelihood of success.  Dragons flight (talk) 06:34, 29 January 2016 (UTC)


 * Sure, but the details matter. Cyanoacrylate will probably perform worse than epoxy in shear (e.g. on the wall); but might perform better on the ceiling; and so on.  Can you at least name the type of glue or adhesive?  Nimur (talk) 15:24, 29 January 2016 (UTC)


 * (ec) I agree with your reasoning. Also, mounting on the wall may result in the object slowly sliding down the wall, especially in hot weather, when certain adhesives become more liquid. But really, I wouldn't use adhesive alone for either case.  The adhesive might serve a purpose, say to stop rattling during vibrations, but really shouldn't be used alone to support weight as described. StuRat (talk) 19:15, 28 January 2016 (UTC)


 * StuRat, you know the composite materials that constitute important control surfaces on a modern commercial airplane like the Boeing 777 are glued on, right? And the outer layer of the space shuttle was also glued on, because welded metal wasn't sturdy enough to withstand ablation during reentry?  Adhesive bonds can be stronger than riveted or welded metal, if the engineers and scientists design them correctly.  Nimur (talk) 19:30, 28 January 2016 (UTC)


 * I doubt if a NASA adhesive is the one being suggested here. Also, even if the adhesive held, whatever it's attached to, like wallpaper, might not hold.  There are reasons we don't glue shelves onto our walls and light fixtures onto the ceiling.  For any substantial weight, you want nails/screws/bolts into the studs, joists, etc.  (Although there are very light duty adhesive patches for hanging light objects on walls.) StuRat (talk) 03:53, 29 January 2016 (UTC)


 * Ordinarily I would reach for screws or nails, but the particular wall / ceiling in question is one which I am not allowed to put any holes in. Dragons flight (talk) 06:34, 29 January 2016 (UTC)


 * As noted below, adhesives can also damage a wall or ceiling. Instead of attaching it permanently, how about just putting the object on a high shelf ?  I had a similar issue with a smoke alarm, and ended up putting it on top of a tall halogen torchère I no longer use. StuRat (talk) 18:46, 29 January 2016 (UTC)


 * Nimur's right, the math of adhesion is crazy hard stuff. But smart motivated capitalists have done a lot of the research and empirical testing for you! Check out these 3M adhesive hook thingies that model is 3lbs load per hook, but they go up to at least 7.5 lb per hook, maybe higher. They are fairly magical IMO. The design routes forces in clever ways, plus the adhesive is very strong in the directions those forces apply --and they remove cleanly when you pull the adhesive in a different direction! So unless "light-weight" means more than ~15-20lbs (in which case you'd be approaching the limits of the wall surface, and should find a stud), I think you can do this with wall-mounted 3M hooks, either using as brackets or hooked to eyelets in the cube. SemanticMantis (talk) 19:39, 28 January 2016 (UTC)

Well, there's one obvious point: depending on the size of the item and how high it's positioned, mounting it on the ceiling may protect it from being bumped into by clumsy people passing by, when if it was on the wall they would knock it off. On the other hand, the ceiling may carry more vibrations from the floor or roof above, depending on what people or equipment (if any) are located there, and if so this may contribute to weakening the adhesive. --76.69.45.64 (talk) 23:45, 28 January 2016 (UTC)


 * I think you are correct and instead of figuring out one case, just imagine the cube is growing in volume but not mass. In the ceiling case, the surface area increases with the volume but the mass it supports is just the normal force to the ceiling. The growing cube on the wall, however, has a moment that increases as the cube increases which is in addition to the normal force (because the center of mass is moving away from the wall).  --DHeyward (talk) 08:47, 29 January 2016 (UTC)


 * If this is a practical question rather than a theoretical one, could you glue it in the angle between a wall and the ceiling or even in a top corner of the room? Thincat (talk) 09:41, 29 January 2016 (UTC)


 * Agreed, tripling the surface area where adhesive can be used would certainly help. However, this requires that the corner be completely square, and they rarely are.  StuRat (talk) 18:50, 29 January 2016 (UTC)


 * I had a tenant who used that double-stick foam tape on the wall to attach a small mirror, which wrecked the wall worse than any nail would-have. The glue made a mess and scraping off the foam was a hard. As for adhesive: I glued a large 1/4-inch thick mirror to the wall with 3M glue and it came off, broke into 1000-pieces, wrote 3M and got the $$$ for a new mirror. If you glue to the ceiling, at least you can brace the object against the ceiling better than something against the wall. Raquel Baranow (talk) 15:45, 29 January 2016 (UTC)


 * I don't understand that last part. How do you "brace the object against the ceiling" ? StuRat (talk) 18:42, 29 January 2016 (UTC)


 * I agree with Nimur and StuRat on this one - if you're going to use "super glue" (any cyanoacrylate adhesive), then ceiling would be your best bet - because the cyanoacrylate adhesives don't cope as well with side, shear or torsional loads as they do with loads perpendicular to the surface where the glue's applied. But since you stated you're not allowed to use metal fasteners (nails or screws) to attach this box, one assumes that you're also going to have trouble when it comes time to detach the box from your wall or ceiling if you use cyanoacrylates - they'll pull the top layer (at least) of whatever surface you glued the box to.
 * 3M has a novel adhesive system called "Command" which has nice adhesive strength, enough to hang picture frames from walls, and can be removed by pulling a convenient tab from the side of the adhesive pad, which doesn't harm either the surface you fasten the object to or the object itself. loupgarous (talk) 20:13, 1 February 2016 (UTC)