Wikipedia:Reference desk/Archives/Science/2016 August 27

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August 27

magnesium

Is magnesium citrate and magnesium sulphate basically the same thing but in a different form? Like water an ice are both h2o? Do they both dilate the epididymis ducts? — Preceding unsigned comment added by 168.9.40.11 (talk) 00:08, 27 August 2016 (UTC)

No, they are not the same thing, any more than water and hydrogen peroxide are the same thing. We don't give medical advice. It should go without saying that "administering" anything into your epididymis is a phenomenally bad idea that could kill you. --47.138.165.200 (talk) 00:16, 27 August 2016 (UTC)

I think you need to actually read the article you linked rather than just blindly posting it. Specifically the section titled Distinguishing between what is and what is not acceptable. From that it is very clear that my question is NOT a request for medical advice. 168.9.40.11 (talk) 00:25, 27 August 2016 (UTC)

You might forgive me for wondering why you are interested in things that dilate the epididymis. It's not exactly a common question. If you are having a possible issue with your epididymis, see a medical professional. --47.138.165.200 (talk) 00:48, 27 August 2016 (UTC)

Well, as I said before this is not a request for medical advice. The article states; "Magnesium citrate, as a supplement in pill form, is useful for the prevention of kidney stones.[4]" This is apparently because it dilates the kidney ducts and allows calcium deposits to pass easily. I was just curious if the same principle applied to the epididymis where calcium deposits also collect. There doesn't seem to be an article on epididymis stones. 168.9.40.11 (talk) 01:12, 27 August 2016 (UTC)

Are epididymis stones are a thing? I did a little looking and I don't think they are. I did stumble upon testicular microlithiasis but that's not quite the same thing. Epididymitis exists, but as the article states it's not generally caused by stones. I believe you are incorrect about the mechanism of action of magnesium citrate on kidney stones. As our article on kidney stones states, magnesium citrate and similar things reduce the risk of kidney stones by altering the composition of the urine. Kidney stones are formed when minerals in the kidney filtrate precipitate into a solid form. Altering the filtrate's composition can prevent this. --47.138.165.200 (talk) 01:36, 27 August 2016 (UTC)

I removed this policy nonsense. We're talking about chemicals here. Wnt (talk) 01:57, 27 August 2016 (UTC)

... and re-removed it. If edit warring is the golden ticket here to get your version of policy to be the rule, we all need to do our part this time. Asking about a chemical's effect on the body, not your body, is routine biology, and I'll not see biology banned from the Science Refdesk. Wnt (talk) 02:37, 27 August 2016 (UTC)

Now as for the question, it's worth noting that ionic compounds are generally the sum of two components, anion and cation. So potassium citrate has some of the same medical applications for kidney stones, but lacks some others, like obviously it isn't a good magnesium supplement. It is worth looking up the two components independently. Wnt (talk) 02:37, 27 August 2016 (UTC)

The top web hit for epididymus and magnesium is this thing (obviously not a quality medical source), which describes some people taking a maximum dose of Epsom salt by mouth. They are not injecting this stuff into anybody's ducts with a needle. The maximum dose recommended on a package of magnesium citrate may be different. I didn't find anything obvious matching this description on PubMed, and there's no guarantee there's any valid theory there or that they're trying to do anything but sell a specific kind of epsom salt pills (I mean, they make a point of linking some kind of epsom salt pills even though I eat (much smaller amounts of) epsom salt on occasion and it's not anything terrible - sometimes bitter tasting, sometimes even sweet tasting, it varies) Wnt (talk) 03:04, 27 August 2016 (UTC)

Time limit for data storage devices

See HD-Rosetta data storage device. It says "Technologies have made HD-Rosetta extremely durable compared to most archival data devices. It has an estimated longevity of 10000 years, and it can withstand a minimum of 1000 years". What does this mean? I didn't know data storage devices had a time limit. Why can't you just store data on a USB stick for 10000 years, or indefinitely? Is there something that prevents storing data indefinitely? 49.199.45.88 (talk) 04:18, 27 August 2016 (UTC)

Sure, materials decay over time. Everything breaks down, and media is only as good as the material it is made out of. Here is a pretty good article about the lifespan of various storage media. Your USB stick (according to that article) is only rated to last about 10 years, not 10,000. This article from 2002 (so a bit dated) rates USB storage devices at about 50 years, which is optimistic, as the media was very new back then; I'd trust the more recent estimates. Wikipedia has an article titled Media preservation which also has some figures for you. It should be noted that these estimates are based on expected averages and reliability; you will find outliers always, but not reliably so. --Jayron32 04:28, 27 August 2016 (UTC)

Thanks for that. That's interesting. It appears that every data storage device has its own unique reason for expiring (photos fade, magnetic tapes lose their magnetism,...). I guess I'm just curious to know if there's some fundamental law that means that *any* data storage device will lose its data eventually. There may not be, but if even HD-Rosetta won't keep its data forever, what will? 49.199.45.88 (talk) 05:30, 27 August 2016 (UTC)

The fundamental law is impermanence. You might be interested to read our article on the Digital dark age and the links therefrom.--Shantavira|^{feed me} 06:54, 27 August 2016 (UTC)

I don't think saying it has a minimum lifespan of 1000 years is accurate, as it certainly could be destroyed before then, say by a meteor. What they could say is that it has a high probability, say 99%, of lasting at least 1000 years. StuRat (talk) 15:16, 29 August 2016 (UTC)

One way valve as an alternative to refrigeration?

Does anything exist that can act as a one way valve for products that have been sterilized ( think salad dressings, etc) that must be refrigerated after opening so that instead of it needing to be put in the fridge, it could stay out in the pantry and still have a similar shelf life? I'm thinking that the only reason it needs to be cold is to inhibit bacteria growth, but if you stop the bacteria from getting into the product in the first place it will still act as though it is sterilized, correct? Seems like it could be a way to lengthen shelf lives after being opened?

2601:406:4C01:5480:CCF8:4DA:F064:50E1 (talk) 05:55, 27 August 2016 (UTC)

If you have it in a squeeze out tube, like toothpaste the inside will stay away from the environment, and only the bit coming out will be exposed. Graeme Bartlett (talk) 08:55, 27 August 2016 (UTC)

This has been known of since they had cauldrons; see perpetual stew. The trick is an airtight lid, and never let it sit below a boil while the lid is off. I've done this myself for over a week, but you can do it as long as you don't get bored. μηδείς (talk) 20:35, 27 August 2016 (UTC)

How much force is needed to keep the lid sealed during the heat up and deboil phases if you had to do it without thermometers like the medieval stews? Wouldn't the pot be under great pressure sometimes because the water either keeps evaporating while you sleep or you turn off the heat and have to boil the sealed pot again? Was ye olde squire releasing the built up water vapor all night? Did they have seals and metallurgy strong enough to raise the boiling point beyond a sufficiently-small fire's heating ability via increased vapor pressure? Thus reaching equilibrium without exploding? Or did Medieval people really have germ-proof one-way valve technology? Sagittarian Milky Way (talk) 22:34, 27 August 2016 (UTC)

Just a reasonably good seal is fine, gravity and the lowering pressure in the pot will hold the lid down when the stew is cooling. While it is actually aboil, you can take the lid off, just make sure you put the lid back on when it is actually close to boiling. (I suspect in the past they kept the cauldron on a permanent low boil, and the kitchen maid stirred it and added water as needed.)

The thing you don't want to do is to take the lid off while it is cool and then put the lid back on without it having been brought to a boil again to kill the germs you have let in. Make sure everyone in the household knows what's going on, as I once had someone take the lid off and tell me it was so the soup would cool faster! You also don't want to get the inside of the lid dirty.

I simply know the process works, and have done it. I'd refer you to the article or a search engine on the topic. I am sure there are lots of enthusiasts who write about this.

OH, and there's the Swan_neck_duct#In_biology (see the article for the picture) that Pasteur used to prove his germ theory. It works on the same principle, but without a valve, and is not suitable for food.

Bag-in-box is one such packaging, but I've never seen it used for salad dressing. :) Vespine (talk) 22:49, 28 August 2016 (UTC)

She's not me, but someone I know drinks bag in a box. I suspect the alcohol content and the fact they never last more that 60hrs have something to do with the lack of vinegar poisoning. μηδείς (talk) 20:38, 29 August 2016 (UTC)

Note that while the one-way valve can keep bacteria from getting into the container, you still have a problem that the valve itself can grow bacteria, especially once left to sit with a food or beverage on it. Therefore, some method of cleaning and sterilizing the outside of the valve is needed to complete the process. Simply flushing the outside of the valve with sufficient tap water is probably good enough to prevent food poisoning. StuRat (talk) 14:18, 29 August 2016 (UTC)

Lichen 4th component

Hey All, I was listening to this scientific American podcast the other day 60 second science when I came across this episode. It is about how scientists in this study found lichen do not just consist of fungus and algae, but also yeast in some cases. It finishes with the scientist speculating that there could be other things that lichen consist of. What would be a likely candidate for this? JoshMuirWikipedia (talk) 06:46, 27 August 2016 (UTC)

Yeast is fungus. —Tamfang (talk) 08:23, 27 August 2016 (UTC)

Some lichens can contain more than one species of multicellular fungus. Some can also vary their algae with differing results. You could also expect that there are bacteria and virus that may live with a lichen, but they may be a parasites rather than useful. And don't forget the mineral kingdom additions, or air, water, stone and dust. Different fungi also partner with other plants by growing on their roots. Graeme Bartlett (talk) 08:51, 27 August 2016 (UTC)

Does an isolated system definitely approach (arbitrarily closely) thermodynamic equilibrium?

The thing about the second law of thermodynamics is that it says the entropy of an isolated system is nondecreasing, not that it is increasing. Strictly speaking, this means that the second law alone does not guarantee that an isolated system will reach its maximum entropy state, or even approach it. Are there additional laws that assure this? 203.45.134.227 (talk) 08:18, 27 August 2016 (UTC)

No. Consider a closed system in a 1G gravity environment that contains a tall stack of ceramic dinner plates and nothing else except pure vacuum. It will stay at that state forever with total entropy neither increasing or decreasing, but if you were to knock the stack over entropy would increase and a small amount of heat would be generated. There are many similar systems such as a leak-proof container of fuel and a leak-proof container of oxidizer sitting side by side. --Guy Macon (talk) 20:22, 27 August 2016 (UTC)

Are those real systems though? They seem like "toy systems" that couldn't actually occur in the real world. I imagine that after an extremely long period of time, quantum or thermal fluctuations would knock over the stack of dinner plates, or the boundary between fuel and oxidizer would begin to decay. I think also that the particles would mix due to quantum tunnelling. 203.45.134.227 (talk) 00:03, 28 August 2016 (UTC)

The system with dinner plates is not in thermodynamic equilibrium until is collapses but there is a large kinetic barrier for equilibration. Ruslik_Zero 20:49, 28 August 2016 (UTC)

A closed system, "but in 1G" doesn't sound like it's closed to me, and there's no such thing as a "leak proof" container. Possibly related is Heat death of the universe. Vespine (talk) 22:47, 28 August 2016 (UTC)

One can also say that entropy is a subjective quantity to begin with. For a given physical system, we decide what properties we're interested in. Ideally we would want to have a set of equations that involve only the variables that describe the properties we're interested in. It then turns out that under certain conditions this is possible but with some additional variables like entropy, temperature, chemical potentials etc. that originate from treating all the other variables needed for a complete description of the physical system, in a statistical way. Usually the variables we ant to keep are macroscopic variables like volume, internal energy etc. The entropy of a system is proportional the the amount of information needed to specify the exact physical state of the system given the incomplete specification using the variables that you keep explicitly (the macro-state if you go about this in the conventional way).

If you instead keep track of all the physical degrees of freedom of the system, then there is only one possible state the system can be in given its specification, so the entropy is zero and the laws of physics are such that information is never lost, so it always stays zero. This entropy is the the so-called "fine grained entropy", while the entropy used in thermodynamics is a coarse grained entropy. While it does depend on the coarse graining procedure inherent in choosing which degrees of freedom of the system are going to be kept in the explicit description, any changes here will only be of the order of a few bits; this means that the relative change in the (coarse grained) entropy of a macroscopic substance of matter will be very close to zero for all practical matters.

The laws of physics will, of course, determine how fast the entropy will increase. But note that the Second Law is a statistical statement that is not absolutely valid. The very justification based in the laws of physics also imply that the Second Law will only be valid on time scales that are not too long. On sufficiently long time intervals, an isolated system will undergo Poincaré recurrences which will bring it back arbitrarily close to the initial state. We may find this result strange, but from Nature's point of view the entropy was actually always zero, and nothing strange has happened. Count Iblis (talk) 00:19, 29 August 2016 (UTC)

If you allowed for an infinite amount of time, then everything should fully decay, including proton decay and other forms. Whether the universe will continue to exist until then depends on which model of the universe and it's ultimate disposition you choose. However, in any reasonable time frame, a system may remain stable. StuRat (talk) 02:12, 30 August 2016 (UTC)

Sodium vs potassium: electrical conductivity

Why is sodium a better conductor of electricity than potassium? (Electrical resistivities of the elements (data page) gives Na a lower resistivity than K.) The obvious way to predict a trend down the alkali metals is that conductivity would increase down the group (Li < Na < K < Rb < Cs), since the outermost electron is less and less tightly held, but instead the trend is Cs < Rb < Li < K < Na; why? Double sharp (talk) 11:08, 27 August 2016 (UTC)

The conductivity has nothing to do with the ionization potential. It depends on the electron-phonon scattering and (pseudo)electron mass. In fact, electrical conductivity is one of the most difficult to calculate parameters. So, the conductivity of alkali metals is generally smaller for heavy elements except for Li. But Li is somewhat an odd member of alkali metal group. Ruslik_Zero 18:35, 27 August 2016 (UTC)

I see the melting points fall going down the group. The alkali metals are simple metals so I'd naïvely expect there should be a straightforward explanation simple answer (at least until we get into relativistic territory). Sandbh (talk) 05:23, 28 August 2016 (UTC)

I found this…

"The resistance of a metal arises from the scattering of high-velocity conduction electrons from the thermal vibrations of the lattice. Irregularities in the electrical conductivities of elements are successfully accounted for in terms of the differences in lattice characteristics and band occupancies (6, 49), but any further consideration is beyond the scope of this article."

(6) Phillips. C. S. G., and Williams. R. J. P. "Inorganic Chemistry." Oxford University Press, New York, 1966,

(49) Meaden G. T. "Electrical Resistance of Metals." Heywood. London. 1966.

…here:

• Edwards PP & Sienko MJ 1983, "On the occurrence of metallic character in the periodic table of the elements", Journal of Chemical Education, vol. 60, no. 9, pp. 691–696, doi:10.1021ed060p691

I couldn't find anything in Philips and Williams that helped. I may be able to look up Meaden tomorrow.

I guess, as per the ionisation energy trend, that the interatomic forces holding the metallic lattices together get weaker going down the group. So perhaps the lattices are structurally weaker, so they vibrate more for any given input of thermal energy as you go down the group. Hence resistivity goes up going down the group. Certainly, I see the Moh's hardness values fall as you go down the alkali metals, suggesting less rigid lattices.

I'm sure the situation gets a whole lot more complicated in metals with more than one valence electron, especially with the transition metals. Sandbh (talk) 07:53, 28 August 2016 (UTC)

Meaden doesn't specifically address this question, but does give some clues:

"In the monovalent elements there is one valence electron per atom, which is only half the number needed to fill the first Brillouin zone. Simple calculation or geometrical construction then shows that in the bcc alkali metals the Fermi surface, if considered spherical, may be contained entirely within the first zone without touching it anywhere. This model would apply for a metal having free or almost free electrons, and the experimental evidence suggests that this is the…[case] in Na and, to a lesser extent, in K. The shape of the Fermi surface is much less simple in the other monovalent metals, because the electrons can no longer be considered nearly free. Even a spherical Fermi surface in bcc metals extends to 90% of the distance from the origin to the nearest regions of the zone boundaries. So in less perfect metals the effect of a periodic lattice field is to distort the Fermi surface from a sphere…"

Meadon does not explain, however, why Na has effectively free electrons, whereas this is less so in K, and even more less so in other monovalent metals. Later he writes

"The explanation of the lower real resistivity of the noble metals is their greater atomic mass on the one hand (compared to Li, Na, and K), which means smaller amplitudes to the lattice vibrations giving therefore a smaller scattering effect, and their hardness on the other hand…It was pointed out that Na and…Rh have very similar absolute resistivities at room temperature. It is now seen that the resistivity for equal lattice vibrations is 45 times greater in Rh than in Na."

So much for my guess :( Sandbh (talk) 02:52, 29 August 2016 (UTC)

Orange

If I have two identical oranges. One I eat whole, the other I put into a juicer and then drink the juice, pulp and all. Which is healthier? My mom says that eating the orange is healthier than drinking orange juice, and that the orange juice does not count as one of my "five a day". Is she correct? Also how does juicing an orange increase its sugar content and "make kids hyperactive" compared to eating the same orange? — Preceding unsigned comment added by 202.20.99.196 (talk) 12:01, 27 August 2016 (UTC)

I'll take a punt and say the whole orange is healthier, as your body has to work harder to get it inside your tummy. You'll get some exercise from the chewing. I can't see how juicing an orange will increase the sugar content, assuming that you don't add any sugar. --TrogWoolley (talk) 12:13, 27 August 2016 (UTC)

Fruit juice has had a bad press recently, see this for example, but as far as I can tell applies to juice made from concentrate. The problem with squeezing it yourself is that you tend to leave the dietary fibre behind, but as you say that you're using "pulp and all", I'm not sure that is an issue here. Alansplodge (talk) 13:11, 27 August 2016 (UTC)

• Define "heathier". And while Alansplodge makes a reasonable point, the "Life and style" column of the Guardian (or of any other mainstream press outlet) is certainly not the place to find scientifically validated information. Tigraan^{Click here to contact me} 13:23, 27 August 2016 (UTC)

The whole fruit contains fibers, and most people don't get enough of it. Orange juice often has sugar added to it, and most people get too much of it. Llaanngg (talk) 13:38, 27 August 2016 (UTC)

When the orange is juiced, the sugars are released from the cells, and therefore have a more significant effect on teeth. If you eat the fruit, most of the sugar will be released further down the digestive system - so healthier for the teeth, even if there is no difference in the total amount. Wymspen (talk) 14:39, 27 August 2016 (UTC)

The main difference is what's tossed in the trash beside the juicer, which is to say insoluble fiber. The 5 a day site for the UK's NHS makes particular comments about fruit juice. [1] Prioritizing which effects of fiber and fruit are most important to you is medical advice we can't give - some people might think more about cavities or constipation than others when making personal decisions. Wnt (talk) 14:54, 27 August 2016 (UTC)

Apologies for quoting the mainstream press User:Tigraan, it was a bit of a quick edit (the article was, however, quoting the Medical Research Council's Human Nutrition Research Unit). A bit more reseach found: Fruit consumption and risk of type 2 diabetes: results from three prospective longitudinal cohort studies from the British Medical Journal, which concludes: "Greater consumption of specific whole fruits, particularly blueberries, grapes, and apples, is significantly associated with a lower risk of type 2 diabetes, whereas greater consumption of fruit juice is associated with a higher risk". Alansplodge (talk) 22:11, 27 August 2016 (UTC)

Tomatoes are the exception. Count Iblis (talk) 22:56, 27 August 2016 (UTC)

It says here that chewing releases enzymes which aid digestion further down the track, which are helpful in maintaining a well functioning digestive system.JoshMuirWikipedia (talk) 02:10, 28 August 2016 (UTC)

You eat the rind too? ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:12, 28 August 2016 (UTC)

I think the complaint about orange juice is that you're consuming the sugary parts of maybe two or three oranges in a 150 gram serving of orange juice, where eating 150 grams of the intact flesh of a single orange has the juice of just one orange and lots of fibre and other stuff. So it's not that the juice is inherently bad for you - or that processing the orange somehow changes the juice - it's that the ease of drinking the juice makes it likely that you'll consume a lot more of the more sugary parts of the orange and a lot less of the pulp. SteveBaker (talk) 04:13, 28 August 2016 (UTC)

And "sugar causes hyperactivity" is a misconception. manya (talk) 05:58, 28 August 2016 (UTC)

Regardless of their studies, sugar definitely messes with your metabolism. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:49, 28 August 2016 (UTC)

As mentioned here, fibers are converted by gut bacteria to short chain fatty acids and other compounds that our bodies need. And it's not just the fibers, also all the nutrients bound to the fibers like polyphenols that are lost when fruit juice is made. So, enriching fruit juice by fibers will still not make the fruit juice as healthy as eating the whole fruit. Count Iblis (talk) 20:01, 28 August 2016 (UTC)

In general, juicing breaks open the cells to release the juice inside, which means it can be digested more quickly, and thus you get more a sugar spike and sugar crash after, than if it was digested slowly. However, citrus has rather large cells, compared to say, a carrot, so you may very well break open all the cells just by chewing. Most people throw out the pulp after juicing, and that's another downside, as digesting that fiber, along with the juice, also slows down the digestion process. One final factor is that it takes more time to eat an orange a section at a time than to down a glass of juice, again slowing the digestion process.

Also note that you wouldn't be able to "drink" the juice with all the pulp included, as it would be too thick for that. When you buy orange juice with pulp, that's just a small portion of the total pulp. StuRat (talk) 15:05, 29 August 2016 (UTC)

There was a study carried out on this very question last year [2] and one of the researchers said: “Those who have interest in their intakes of pectin and fiber may wish to consider oranges and orange puree. When considering sugar content, there is no difference between fresh oranges versus pure orange juice. All foods evaluated can be considered as a good-to-rich source of vitamin C.” Richerman (talk) 23:43, 29 August 2016 (UTC)

It also said "According to the USDA’s Nutrient Database, one cup of orange juice contains less than a gram of dietary fiber (0.7 gram), while a cup of orange segments has 4.3 grams of fiber." That's over 6 times as much, and fiber is critical to health. StuRat (talk) 00:32, 30 August 2016 (UTC)

"The OP asks "If I have two identical oranges. One I eat whole, the other I put into a juicer and then drink the juice, pulp and all. Which is healthier?... Also how does juicing an orange increase its sugar content." They didn't ask whether drinking a cup of orange juice without the fibre was as healthy as eating a whole orange. Richerman (talk) 09:29, 30 August 2016 (UTC)

There's no harm in providing additional information. Besides which, the OP is a one-shot drive-by. But other readers might be interested. ←Baseball Bugs ^{What's up, Doc?} carrots→ 10:37, 30 August 2016 (UTC)

And, as I previously explained, it's not possible to "drink" an orange, pulp and all, as that would be too thick to drink. They are likely confused by orange juice sold in stores "with pulp", which is only a small portion of the pulp of one orange, with the juice of many, which both increases the sugar content and decreases the fiber relative to eating a single orange. StuRat (talk) 12:17, 30 August 2016 (UTC)

The big complicating factor here is the OP hasn't really explained what they meant. However I agree with Richerman that it doesn't sound like they were talking about throwing away any of the pulp or adding fibre but a lot of the answers seem to have referred to to that case.

I do question the claim it can't be drunk. Actually you seem to be contradicting yourself by saying you can drink some, but can't drink it if it's too much. Well I guess if we're really talking about nothing added at all and only just the orange the perhaps it's correct (although an orange is one fruit where it may be possible). But while the addition of plain water may complicate analysis of dietary effect, it isn't uncommon people will drink some water with fruit anyway so it's not necessarily a different situation.

To give an example, I've blended whole Feijoas (including skin) before and with sufficient water they are drinkable. There will still be some loss because it's not possible to get everything off the blender or the cup (presuming you don't drink direct). By that token, you're better off leaving it fairly thick such that you may need to wait for it to pour and then adding some water to get more of the dregs. Using a scraper obviously helps. Since obviously the solid bits tend to stick more, the percentage of fibre lost is like greater than other components (so it's not like you can make up for it by using more). Still, I'm not convinced it's that significant. With oranges, you'll likely want to remove the seeds.

Incidentally, I stopped doing this mostly because I read more and decided it's not likely to be the same as eating the fruit. Richerman's source mentioned an increased bioavalability of nutrients, but I've also read sources suggesting a decreased bioavailability in some cases (due to it being digested differently and in different places). Especially of concern if you are eating (or well process) a lot of fruit is that while the sugar content doesn't change, digestion of it will. There may be a more significant spike etc. (Someone did mention the effect on teeth but I don't think it'll stop there. Other results sort of hinted at these various possibility but were confusing since they seemed to refer to a case when significant pulp was lost or fibre was added.)

BTW I saw this early on and planned to dig up decent sources before I replied but meh. As with any dietary advice, any results should be looked at with caution, still I wouldn't assume the same effect just because you're consuming the same thing. We know enough to be fairly sure that there can be changes depending on what it's like when it reaches the stomach.

The OP specifically mentioned a juicer rather then a blender. This is actually different yet again. The pulp will generally stay more intact and there'll I think be less destruction of the cell walls. (But this doesn't mean you can't drink it. Again - water.) Possibly the blender case is closer to pulp mentioned in Richerman's source but I didn't look in depth. So this will likely be somewhat in between the two but it'll also be complicated than that.

Nil Einne (talk) 16:22, 30 August 2016 (UTC)

You could certainly swallow the pulp. Whether you're drinking or eating it is a matter of semantics. Richerman (talk) 16:50, 30 August 2016 (UTC)

I disagree. At the point where it will no longer flow out of a glass into your mouth and you need to use a spoon to consume it, that is eating, not drinking. StuRat (talk) 19:09, 30 August 2016 (UTC)

See here. Count Iblis (talk) 17:46, 30 August 2016 (UTC)

For those who don't want to watch that entire video, it doesn't mention juice until 9.5 mins in, and doesn't talk about juicing and blenders until 11 minutes in. The point made is that the fiber is broken up into smaller bits by these processes, which makes it more quickly digested and thus reduces satiety, causing you to eat more of other foods. StuRat (talk) 19:32, 30 August 2016 (UTC)

What triggers a regular childbirth?

Oxytocin? Other hormone? But what triggers these? How does the body "know" that the baby is ready? Or, does the baby trigger the whole process? Llaanngg (talk) 13:39, 27 August 2016 (UTC)

Our Oxytocin article explains: oxytocin causes contractions during the second and third stages of labor -- so it doesn't seem to play a role in the onset of labor. Childbirth § Onset of labour mentions oxytocin as having a possible "synergism" with melatonin relating to reports of labor more commonly occurring during late night and early morning hours. This doesn't answer your question, however; but I hope it helps clarify a bit. 2606:A000:4C0C:E200:1821:CD59:E35A:CB68 (talk) 18:03, 27 August 2016 (UTC)

The first clear sign of childbirth is the appearance of regular uterine contractions. The mechanisms that cause contractions to start are complex and not completely understood -- for a rather thorough recent review you could look at http://humupd.oxfordjournals.org/content/16/6/725.long -- it's not easy reading though. Two factors that clearly play a role are oxytocin and prostaglandins. Looie496 (talk) 18:14, 27 August 2016 (UTC)

(Courtesy link added: 2606:A000:4C0C:E200:1821:CD59:E35A:CB68 (talk) 18:25, 27 August 2016 (UTC))

Both prostaglandins and oxitocin are also used to induce labor. Vespine (talk) 22:53, 29 August 2016 (UTC)

You can tell they are ready to give birth when their belly button pops out. :-) StuRat (talk) 00:33, 30 August 2016 (UTC)

Stu, you deserve a spanking. Probably not from me though, given I am 79", 380lbs, and have a rather large...clitoris. μηδείς (talk) 03:31, 30 August 2016 (UTC)

Based on my paternal experience, a good, reliable pathognomonic sign of impending childbirth are bruises on the arm or upper torso of the husband or other attendant during transition phase labor. It's why the OB nurses mysteriously vanish then, their hospitals won't authorize workers' compensation claims for anything a woman in transition does to them short of breaking a limb. loupgarous (talk) 23:42, 30 August 2016 (UTC)

Order of substituents in the IUPAC nomenclature for organic chemistry

Hello.

In the nomenclature of organic chemistry, whenever there are several substituent prefixes of different lengths where each prefix begins exactly the same as the next shorter one, how are they sorted to generate preferred IUPAC names?.

Example: What prefix goes first, "methyl" or "methylphenyl"?. So is it "1-methyl-2-(methylphenyl)-propan-1-ol" OR "2-(methylphenyl)-1-methyl-propan-1-ol"?.

I checked P-14.5 of the IUPAC Blue Book 2013 but it is not clear if this provides a decision rule. It provides rules for the case when "all Roman letters are identical". I would say that here they are not identical.

What is the official decision rule here for preferred IUPAC names according to the Blue Book 2013?.

I am interested exclusively in what the official standard has to say on the matter. I searched but I did not find anything conclusive.

Regards and thanks. Mario Castelán Castro (talk) 17:35, 27 August 2016 (UTC).

P-14.5.2 (at least in a draft...I don't have final 2013 handy) indicates that a whole substituted substituent is treated as a single word. Standard alphanumerical order places "methyl" before "methylphenyl", same as any case where one word is the initial part of a longer one. I think your whole example (either name) is not "best IUPAC" in two other ways: first, there is a butyl parent that takes priority over the propyl ("2-hydroxy-3-(methylphenyl)-butane" or "3-(methylphenyl)-butan-2-ol", etc.). Second, "methylphenyl" as a substituent is ambiguous (unspecified locant for the methyl on the phenyl)--doesn't matter for purposes of your question because the number X in (X-methylphenyl) is not required to break the tie. DMacks (talk) 20:47, 27 August 2016 (UTC)

DMacks: Thanks. You are right; apologies for the bad example. Fortunately you understood my question anyway. Do you know if any part of (your draft of) the Blue Book says explicitly that when comparing 2 words one of which is the initial part of the other, the shorter one goes first?. Mario Castelán Castro (talk) 21:56, 27 August 2016 (UTC).

Gerry P. Moss (who handles errata reports for the Blue Book) confirmed that this is the correct interpretation. Mario Castelán Castro (talk) 20:11, 28 August 2016 (UTC).

No more authoritative source than that! But the general ordering of "[string] before [string][string2]" s a standard part of Alphabetical order and any sorting algorithm based on it. DMacks (talk) 20:18, 28 August 2016 (UTC)