Wikipedia:Reference desk/Archives/Science/2017 August 2

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

August 2

Maladaptive personality traits in nonhumans?

I am aware of the fact that dogs and cats and goats and horses all have their own personalities. So, how does a veterinarian determine whether a living thing has a psychological disorder or a diseased or injured brain? 50.4.236.254 (talk) 03:57, 2 August 2017 (UTC)

Read the Wikipedia article Animal psychopathology for an introduction. --Jayron32 10:54, 2 August 2017 (UTC)

Note also that most of the non-lab studies quoted there - the case studies - are primarily brought up by the animal's owner: they notice the behavioural or physical symptom and take it to the vet. Matt Deres (talk) 14:50, 2 August 2017 (UTC)

I've occasionally had cause to reference veterinary practice guidelines/reference works over the years, and where such the disorders are concerned, the one point I've seen emphasized more regularly than any others is that it is that it is a process of elimination to arrive at a behavioural diagnosis--that is to say, other likely physical causes which can be reliably tested are ruled out. Of course, sometimes its more complex still, insofar as a particularly behaviour may arise from a complex of physical and psychological causes. And others may blur the line between the two, with mental state exacerbating a physical condition (and of course, vice versa). For example, in cats, hypersensitivity issues are notoriously difficult to diagnose. Snow ^{let's rap} 00:18, 3 August 2017 (UTC)

All dogs have recently been shown to have (an analog of) Williams syndrome, to make them super friendly; it's what makes them not wolves. [1] I vaguely remember that a Russian Domesticated Red Fox program was said to produce similar facial features, so I wonder if domesticated foxes also have this syndrome. But I've seen nothing on that one! Wnt (talk) 21:25, 3 August 2017 (UTC)

Fitting a glass frit filter

I've just received a glass frit filter in the mail and tried to fit it into my benchtop setup, but I have a slight problem: it's precisely 1 mm wider than the pipe and won't fit, and the next smaller size is precisely 4 mm smaller than the pipe (which means that the pressure would drive the catalyst into the gap and possibly cause it to fuse with the filter). Here are my options: (1) grind down the edges of the filter so it will fit; (2) scrape off a thin (0.5 mm) layer from the nonstick lining inside the pipe so it will fit; or (3) get the next smaller size and put a 2-mm thick acid-resistant gasket around it so it will fit. Of these choices, which is the best one? 2601:646:8E01:7E0B:FCEE:E7DF:4CAD:C2E5 (talk) 04:20, 2 August 2017 (UTC)

Can you get a glassblower to customize an adapter for you? Most moderate-sized chemistry labs have a glassblower on staff to handle such issues (I know we had a full time one working for the Chemistry department back when I was in college). There may also be a local scientific glassblower who does work like this if you don't have access to one through the lab you're working for. Just an idea. --Jayron32 10:53, 2 August 2017 (UTC)

You may ask Technical Glass Products, Inc. who advertise frit filters in standard diameters from 10 to 100mm and offer custom fabrication whether they have a solution. Blooteuth (talk) 14:31, 2 August 2017 (UTC)

A reasonable answer depends on the chemicals and rate of flow. How had you planned to attach it previously (assuming it were the perfect size)? If you have a non-stick coating and you remove it, will you be exposing the pipe to damage? DMacks (talk) 14:34, 2 August 2017 (UTC)

Should the tubes have a standard inner diameter so other (standardized) elements of a set/system/kit always fit? --Kharon (talk) 16:47, 2 August 2017 (UTC)

Glass adapters are out of the question due to the pressures involved (300 psi working pressure, transients as high as 900 psi due to water hammer); the chemicals involved are copper salts and phosphoric acid; the filter is supposed to be a push fit into the pipe (and reinforced on both sides with stainless steel mesh to spread the load and thereby prevent breakage); the non-stick coating is thicker than 1 mm, so I won't be exposing anything to damage; and the pipes have a standard outer diameter so that the other fittings always fit, and in theory that would imply a standard inner diameter as well, but this is not the case in practice because (1) some of the pipes are welded so the bead infringes on the inner diameter, and (2) the non-stick PFA coating (applied only to the inside of the reactor components) also reduces the inner diameter compared to the nominal one. Hope this clarifies everything. 2601:646:8E01:7E0B:D46F:CEA1:70BA:C0B8 (talk) 00:53, 3 August 2017 (UTC)

If glass adapters won't work, perhaps metal ones will. In that case instead of a glass blower, you need a machine shop who could make a custom adapter out of metal. There's always someone who can make something for you, if an off-the-shelf solution doesn't exist. --Jayron32 01:36, 3 August 2017 (UTC)

Well, I've already made a custom metal adapter (did it myself, with a forging press and a lathe) -- problem is, when I had it coated, I got the coating just a tiny bit too thick. So, do you recommend that I scrape off that tiny extra bit of thickness so as to make it all fit? (Correction: I've just double-checked my dimensions, and found that the coating is not to blame -- rather, the diameter I bored out is infinitesimally too small. So scraping off the coating won't solve anything, because I'll have to scrape it all off, and then shave off some of the metal as well. So, I'm down to 2 choices -- either grind down the edges of the filter, or get the smaller size and a gasket to go with it. Which of these is better?) 2601:646:8E01:7E0B:8CEA:4A9:11B:99DA (talk) 06:22, 3 August 2017 (UTC)

Tho metal may react with the chemicals you use. Far as i know thats why somuch inert glass and ceramics is used in chemistry. --Kharon (talk) 07:48, 3 August 2017 (UTC)

Not this metal, though!  :-) 2601:646:8E01:7E0B:9149:D64B:8DA2:C52C (talk) 23:35, 3 August 2017 (UTC)

The Refdesk isn't a place for giving professional advice, and when you belatedly mention an application that involves 20 atmospheres of pressure and phosphoric acid, it goes to show that we are far out of our league we can end up! No answer you are given should be trusted to have a mayhem-free outcome. Unless you think of this solely as an exercise in creative thinking, you don't need a lot of unsourced guesses from people who don't claim to have done similar work themselves - you either need to have confidence in your own decisions, or a consultant who you can trust. Wnt (talk) 17:14, 3 August 2017 (UTC)

Not to worry, I've already asked the manufacturer and they told me to grind down the edges. 2601:646:8E01:7E0B:9149:D64B:8DA2:C52C (talk) 23:35, 3 August 2017 (UTC)

Resolved

2601:646:8E01:7E0B:9149:D64B:8DA2:C52C (talk) 23:35, 3 August 2017 (UTC)

Atlantic hurricanes

1. If there was never any wind shear, when would the average hurricane season peak? Would it be earlier than September 10 since tropical cyclones cool the water?

2. If there was so much near-uniform random wind shear 24/7 that tropical cyclones barely cooled the ocean anymore, when would the average (weak) topical cyclone season peak?

3. Why is it that when the most common hurricane forming areas have the warmest water it's also the low wind shear season? Coincidence? Cause-and-effect? Sagittarian Milky Way (talk) 16:43, 2 August 2017 (UTC)

The formation of tropical cyclones is the subject of the study known as cyclogenesis, specifically the subfield known as tropical cyclogenesis. I would start your research at those articles. --Jayron32 16:47, 2 August 2017 (UTC)

See Reynolds number regarding the physics of turbulence and Laminar-turbulent transition to understand "wind shear". Also local low wind is not a sign for a low whole system. In some cases like the famous eye of the storm its even the opposite. Generally fluid dynamics is very complex (or chaotic) stuff and in consequence we have for example the tremendos difficulty of weather prediction. --Kharon (talk) 17:05, 2 August 2017 (UTC)

Tremendous is the correct spelling, in case we mislead non-native speakers who may read this. Akld guy (talk) 06:49, 5 August 2017 (UTC)

2 degrees of warming

What exactly will happen if Planet Earth warms up by 2 degrees Celsius or more?Uncle dan is home (talk) 17:24, 2 August 2017 (UTC)

Its unclear since our Planet has multiple distinct ecological parts which are all supposed to be in a balance (with eachother). Since we seem to tip the balance there may be cataclysmic events like for example when the arctic thundra permafrost starts to melt, it is expected to release the huge additional quantities of carbon dioxide and methane which are stored savely in it now (Permafrost carbon cycle), which ofcourse will speed up or extend the global warming. --Kharon (talk) 18:17, 2 August 2017 (UTC)

Nobody knows exactly. But thousands of scientists around the world have some pretty good projections, and they continue to refine their understanding of the phenomena, through model predictions, additional data, etc. For our coverage on the topic, see Global_warming#Observed_and_expected_environmental_effects, and Effects_of_global_warming, and Physical impacts of climate change. While none of the research presented there will give exact predictions, many specific predictions are covered. If you have any specific questions about projections described there, let us know. SemanticMantis (talk) 19:12, 2 August 2017 (UTC)

Nothing happens in a vacuum. If the temperature starts to trend upwards, a point may be reached at which so much moisture is boiled out of the ground and from melting polar ice that it forms continual cloud and rain. The result would be gloomy days, day after day. The cloud would counter the heating effects of the sun, and reduce temperatures again. So, while there may be a 25 year upturn in temperature that concerns scientists who cannot think further than their 25 year old computer models and extrapolate them to doomsday, it will all balance out in the longer run. Akld guy (talk) 21:41, 2 August 2017 (UTC)

Scientists are not that stupid. And the last superinterglacial reached sea levels of 20 feet. Humans have a lot of shit below 20 feet. Sagittarian Milky Way (talk) 22:59, 2 August 2017 (UTC)

Yes especially on a field fraught with misinformation I agree a big for any of Akld's claims. SemanticMantis (talk) 00:34, 3 August 2017 (UTC)

Effects of changing albedo due to changing moisture and cloud content are taken into account in climate projection models, so your point is moot. --OuroborosCobra (talk) 14:03, 3 August 2017 (UTC)

There are many unknowns, but let's focus on the parts we know for sure:

1) Sea levels rise, due to melting glaciers and oceans water expanding at the higher temps.

2) Tropical storms and hurricanes/tropical cyclones increase in number and/or strength and duration, as they are generated by warm water.

3) Crops shift towards the poles. See bloom clock.

4) Ice clears in the Arctic Ocean in summer, potentially opening the Northwest Passage to ships and endangering polar bears. StuRat (talk) 22:43, 2 August 2017 (UTC)

2 seems a little counterfactual, based on the weather records we have. The economic impact of a given storm is greater, because we've got more people and more stuff, but the actual frequency and strength of high intensity storms shows no trend. Greglocock (talk) 23:04, 2 August 2017 (UTC)

That's because global temps have barely risen so far, certainly nowhere near 2 degrees C. In the range of change we've had so far, it's easily swamped by variations from El Nino, La Nina, etc. But, we know that warm water causes these storms, and therefore warmer water must cause more and/or worse storms. StuRat (talk) 23:10, 2 August 2017 (UTC)

Actually, global temperature averages have risen about 0.90°C above the 20th century average when comparing like months. So, while it hasn't gone up 2 degrees, I wouldn't call that "barely"; 0.9 is a sizable way towards 2. --Jayron32 02:06, 3 August 2017 (UTC)

You see, this is where statistics are misleading. Most temperature readings prior to 1900 have been lost and all we have left are mostly capital city temperatures. The further back you go, the fewer statistics are available, until they dwindle out prior to say, 1800. Fast forward to the 1960s or so. From then onwards, not only are far more temperature readings available, but sensors have been placed at the most unlikely places where temperatures were never historically taken. What we have seen since the technological explosion since the 1960s is a far more accurate average figure for the world's temperature. A more accurate figure is not the same thing as a sharp rise in temperature. Akld guy (talk) 02:28, 3 August 2017 (UTC)

Shock Brigade Harvester Boris (talk) 03:11, 3 August 2017 (UTC)

So are you, StuRat, now claiming that despite a 1/2 doubling of CO2 in the atmosphere there has been no particular temperature rise? Oh. Welcome to denialist land (not actually a claim I'd make, I think CO2 is rising and has caused some of a temperature rise since 1880). Greglocock (talk) 04:58, 3 August 2017 (UTC)

You completely misread what I said. I get a 0.74°C rise over the last century: [2]. The OP asked about an additional 2°C rise over that, or almost 3 times what we've seen so far. This can be predicted to have much greater effects, enough to overcome the normal yearly variations caused by the other effects I've mentioned. So, it should become apparently that hurricanes are more often and/or more severe when that occurs, even if it is not yet. StuRat (talk) 05:34, 3 August 2017 (UTC)

Well in a way it has only started. There is a large lag in the effect because the ocean takes a long time to heat up. However that also means that even if we were able to magically reduce CO2 to pre-industrial levels the current warming wouldn't immediately disappear and with constant level, also completely unrealistic, it would still go up. It looks like we're well on the way to Effects_of_global_warming. We'll need lots more solar cells just to power the extra air-conditioners. Dmcq (talk) 09:58, 3 August 2017 (UTC)

ref desk is not a forum, nor a future teller, so i think we should just close the question

Note however:

1) weather and climate (and also the biosphere) are chaotic system; the idea of chaos came in the mind of Edward Lorenz because ... but just read Chaos_theory#History. Any method to make a better than random prediction of what will happen in a chaotic system, would be worth more than anything in current world, dwarfing all the biggest magnates together (imagine the difference in magnitude between solving chaos and just answering queries, look at the fortune google and oracle are making, now just imagine the riches we are talking about...). Meaning, don't believe anyone that pretend to have good (or even not so bad) prediction of what will happen, unless the guy (or at least one of his student) is competing for the title of richest and more powerful man on Earth with a few fellows that apply the very same technique of prediction (nobody else could compete with them).

2) "degrees Celsius" measure temperature, while warming is a matter of heat, which unit is joule. This is not just a minor point of detail, it is a major issue (e.g. Ocean heat content)

3) there is no such thing as a "normal temperature" to be used as a reference for a 2°C increase. "Current temperature" (even when taking a 30-year or 60-year running average) change all the time. As far as we know (and we know not much, even now: for instance, Argo floats are just a few thousand, that's one for a 3°square latitude x longitude), it is already an average ~1°C from a few decade ago (when the fear was global cooling), but also ~3°C higher or lower from not so far in the past. Antarctica once was a tropical forest (but no human existed to complain, this far back).

Last but not least: whatever happen or is expected to happen, life and intelligent people will adapt to exploit opportunities, poors will suffer, haters will hate, fearful will cower, complainers will complain, and cynics will make a profit (in power or money, depending on their focus) out of other people suffering, hate, fear and complain, as Al Gore, Elon Musk, and some smart others did. Nihil novo sub sole.

Gem fr (talk) 13:56, 3 August 2017 (UTC)

Fans of unintended irony will note that you begin by saying "ref desk is not a forum", then proceed use the ref desk as a forum. Including, of course, the obligatory invocation of Al Gore. Shock Brigade Harvester Boris (talk) 14:10, 3 August 2017 (UTC)

I expected that one, I am not disappointed ;-) Gem fr (talk) 16:01, 3 August 2017 (UTC)

That's a total misrepresentation of chaos and how climate and weather works. Simply put, merely because a system is chaotic doesn't mean it's unknowable. Indeed, chaos theory is all about how to make predictions about the behavior of chaotic systems. The classic example here is statistical thermodynamics, Ludwig Boltzman and all that. The movement of individual atoms is chaotic, but the behavior of a system of atoms in terms of the movement of heat and energy is highly predictable. The same is to be said about weather and climate; individual weather events are like individual atoms moving around in the air around us: making long term predictions of the exact weather on a specific day and a specific place is akin to predicting the motion of one atom: so chaotic as to be unpredictable. Climate, however, is akin to statistical thermodynamics: predictability comes from not worrying about individual atoms, but instead on emergent phenomena in the whole system. Systems are predictable even if the elements of those systems behave chaotically on an individual level. Weather is chaotic. Climate is not. --Jayron32 14:39, 3 August 2017 (UTC)

I also expected that one, it had to be written by someone. Now you can delete it yourself: Climate is chaotic, of its own [3]. That's just climate 101, you denier (pun intended ;-) ).

Chaos doesn't mean "unknowable", of course. Weather is chaotic, but 7 days predictions are pretty good nonetheless, nowadays; it just gets exponentially worse for longer time period, until nothing can be predicted at all. It is even worse for climate, we just cannot predict it for just next year, and we cannot even explain what happened last year (as opposed to meteorologists, who usually know afterward why they went wrong).

Chaotic systems are NOT solvable by statistics, a system that can be cope with methods like statistical thermodynamics are simply NOT chaotic, even though some of their smaller scale component may be (e.g. a simple glass of water is just as chaotic, as it's molecules go, than a gas, and you don't even need statistical thermodynamics to predict its movement, Newton's law are enough)

Gem fr (talk) 16:01, 3 August 2017 (UTC)

A glass of water is not just as chaotic than a gas, because the molecules of water have fewer Degrees of freedom than the gas does, and thus has lower entropy. And you're still abusing the difference between climate and weather, and still making assertions without evidence. --Jayron32 12:12, 4 August 2017 (UTC)

You should rather stop posting false stuff, specially in the ref desk. What trust do you expect to get? The double pendulum only has 2 degrees of freedom and it is a chaotic fun thing, while a plane with 6 degrees is not (in most case, that is, you surely can turn it in a chaos, but you should not).

A molecule of water have no less than 9 degrees (3 motion, 3 rotation, 3 vibration), more than most gas in atmosphere (N2 and O2 have 7 because of only 1 vibration mode, Argon 3 for lack of rotation and vibration mode).

Chaos is not about entropy or degree of freedom. Gem fr (talk) 13:46, 4 August 2017 (UTC)

I provided reference from a lead author of IPCC, you did not (for a cause: it is just impossible to use "statistical thermodynamics" as you pretend, that's why IPCC do not do that). I made you a favor, deleting self-deserving flame that do not belong here (but feel free to restore if you insist ridiculing yourself. Gem fr (talk) 12:42, 4 August 2017 (UTC)

To amplify on this point, merely saying that climate is "chaotic" misses the mark. It has more-or-less linear forced components along with nonlinear components that produce chaotic behavior. A simple example: I can't predict the temperature in my town six months from now (4 February 2018) because the chaotic parts of the system make such a specific prediction impossible. But I can confidently say that February will be colder than August because mid-latitude continental climates respond strongly to forced part of the system arising from the annual cycle of solar radiation. Teasing out the forced component from the nonlinear "noise" is one of the central topics of climate change attribution (although that article that really needs to be improved). Shock Brigade Harvester Boris (talk) 12:23, 4 August 2017 (UTC)

This is a rather common misconception of chaos: that it can be decomposed into a linear part, and a nonlinear "noise". This is simply NOT true, as every mathematician will tell you. As climate goes, Lorentz wrote an article that i resume "guys, stop this nonsense, this just cannot be done", but just read it yourself [4] (As the saying goes, "it's very rare for people to understand a point, when their job depends on not understanding it", so, people, self labeled "scientist" just kept doing what science forbid them to do). For instance, adding some prey in a chaotic prey-predator interaction (or suppressing some food in the chaotic human metabolism) won't result in the same result with just more prey (or some less weight) in the end, it will result in a completely other result. Same with climate: forcing just don't add up to a same result + the forcing, thing will ends completely different result.

So you can "confidently say that February will be colder than August", sure, but that's not what your previous sentence imply (non sequitur). Your previous sentence implies that, if February is hotter (or colder) than previous, then there is some linear underlying trend that also applies to august, so August will also be hotter (or colder) than previous. Well, good luck providing reference for this (tip: you won't, that's what chaos is all about) Gem fr (talk) 13:22, 4 August 2017 (UTC)

In practical situations of chaotic systems one would decompose into a chaos component and a noise component. For weather the climate puts in a trend component. You are just invoking 'chaos' as a thingamajig - if anything being able to classify some of the variation as chaos actually means one can understand and predict it better compared to just noise and anyone knows that one can find a trend despite noise. Dmcq (talk) 21:24, 6 August 2017 (UTC)

We live in a global civilization, there exists a global economy that has some vulnerabilities. The 2008 financial crisis clearly demonstrated that things can go wrong even if there is nothing external that's perturbing the system. A minor perturbation of the system can then easily lead to a collapse of our civilization. E.g. a prolonged drought in China and India could cause these countries to import most of the food they normally grow themselves. They have more than enough financial reserves to buy all the food they need, but the problem is then that this causes a lot of the food meant for the internal markets in the EU and the US to be exported away to India and China. Export limits will then be imposed which will violate free trade agreements, leading to disputes that will ultimately undermine the global economy. The moment the worth of money is made dependent on who has the money, that's the end of the economy. Count Iblis (talk) 15:00, 3 August 2017 (UTC)

I recently encountered a glum review at [5], though I think you'd have to find it at a library, and I'm not sure it is worth the aggravation. Some of the heat wave stuff it mentions matches this article; CNN claims a 95% probability of a 2-degree rise by 2100. [6] Note that sourced prediction of scientific studies is not a crystal ball and is absolutely on topic here. I've only scratched the surface and I'd encourage folks to pull in more sources rather than argue with each other. Wnt (talk) 21:34, 3 August 2017 (UTC)

Are you talking about the cover story of that issue? It's online, and linked from that page. There are also some interviews with prominent climatologists worth reading. If you're getting some paywall, delete cookies for the site/use private browsing, and/or use an ad blocker. I don't get any paywall, though I guess there could be geotargeting (I'm in the U.S.). Though, I encourage anyone who can to subscribe; New York has some pretty good articles. --47.138.161.183 (talk) 21:48, 4 August 2017 (UTC)

Who makes the most oxygen?

Can you point me to a breakdown for what produces the most atmospheric oxygen gas on Earth? For example, how much is produced by cyanobacteria, protists, multicellular plants? How much is produced by life in sea versus on land, or how much do rainforests contribute in particular? I'm interested only in the last hundred thousand years here, not the geological history. – b_jonas 20:16, 2 August 2017 (UTC)

Wikipedia's article on Oxygen cycle contains some crude numbers, showing that well more than 50% of the earth's oxygen is produced by phytoplankton, but doesn't get finer distinction than that. It does, however, cite sources which may lead you to more information to aid your research. --Jayron32 01:32, 3 August 2017 (UTC)

Thank you for pointing to that article, I haven't checked that one. While that article doesn't say that the phytoplankton accounts for most of the oxygen production, Phytoplankton does say: “Phytoplankton account for about half of all photosynthetic activity on Earth”. It gets this statement from "Satellite Sees Ocean Plants Increase, Coasts Greening". NASA. 2 March 2005. Retrieved 2017-08-03.. That article says its main source is “[Watson] Gregg and his colleagues published their new study in a recent issue of Geophysical Research Letters.” which is sort of a rude way to give a reference, but luckily in the internet age it is enough to find the article: Watson W. Gregg; Margarita E. Conkright; Paul Ginoux; John E. O'Reilly; Nancy W. Casey (2003-08-09). "Ocean primary production and climate: Global decadal changes". Geophysical Research Letters. 32 (15).. That article gets the claim from Michael J. Behrenfeld; et al. (2001-03-30). "Biospheric primary production during an ENSO transition". Science. 291 (5513): 2594..

That article looks like an actually relevant article: it talks about measuring how much photosynthesis sea and land life does, so it should give the breakdown between land and sea. It also links to two previous studies about the same. I find that article a bit confusing, but I think it does indeed say that about half of the photosynthesis is done in the sea. That is definitely a datum I find interesting and partly answers my question. – b_jonas 05:41, 3 August 2017 (UTC)

It shouldn't be surprising, given that Earth's surface is 71% water, but we tend to anthropocentrically focus on land more than water. Actually, given that, I'm a bit surprised it isn't higher. I wonder if land plants are more efficient at photosynthesis. Or maybe leaves give plants more surface area per parcel of land, allowing more photosynthesis than an equivalent area of water. --47.138.161.183 (talk) 06:26, 3 August 2017 (UTC)

Primary production has a nice Primary_production#Primary_Production_and_Plant_Biomass_for_the_Earth and some explanations; basically, most of the ocean miss nutrients and has a low productivity because of that. Where nutients are plenty, ocean production is higher than anywhere on land, tropical forest included Gem fr (talk) 15:10, 3 August 2017 (UTC)

Thanks for pointing to that article, Gem fr. It's definitely relevant, I'll look at it in detail. – b_jonas 17:35, 3 August 2017 (UTC)

That one has a breakdown by type of vegetation on the areas, which seems useful. It's probably older than the article I mentioned above, but still useful information. – b_jonas 18:58, 3 August 2017 (UTC)

Those numbers are for atmospheric O2. Presumably a lot of oxygen is produced and then consumed in the ocean itself. Fish gotta breath something. 15:19, 4 August 2017 (UTC)

That's great, because I did ask for atmospheric oxygen specifically. – b_jonas 21:33, 6 August 2017 (UTC)

Rice and beans

So many sources say that rice and beans make up a complete protein. But I wonder if it depends on the type of rice. Isn't white rice mostly starch? Where is the protein? Or is there actual protein content (whatever amino acid, I don't know) in both brown rice and white rice? As for beans, they certainly are rich in indigestible carbohydrates and proteins and relatively low in fat. But in regards to rice and beans, I wonder how exactly they are "complete". How do they complement each other? 50.4.236.254 (talk) 22:55, 2 August 2017 (UTC)

When people talk about "complete" in this sense, they mean something that contains all the essential amino acids. Beans, generally, are low in methionine and high in lysine, and rice is high in methionine and low in lysine. Thus they complement each other. It's about the amino acids; it has nothing to do with the carbs.- Nunh-huh 23:02, 2 August 2017 (UTC)

I know that "complete" means "contains all amino acids". That was not my point. You do bring up the actual figures. But I still struggle in understanding how white rice, with the outside shell removed, will have protein. I should expect all carbs. 50.4.236.254 (talk) 23:48, 2 August 2017 (UTC)

White rice is about 3.2% protein, whereas brown rice is about 9% protein. This means that while white rice contains less protein than brown, it does not contain zero protein. In other words, it's not the best thing you could eat in this regard, but it also isn't terrible. --Jayron32 01:29, 3 August 2017 (UTC)

And other sources show even less difference: the USDA National Nutrient Database says a cup of cooked white rice contains 4.25 grams of protein, and a cup of brown rice contains 5 grams of protein. - Nunh-huh 02:50, 3 August 2017 (UTC)

Note that amino acids are the building blocks of proteins, but they are often used interchangeable in casual speech. Thus, we say a food that contains all the amino acids has "complete proteins". StuRat (talk) 23:13, 2 August 2017 (UTC)

Proteins are digested to amino acids or very short polypeptides in the gut before entering the blood stream, so though you eat proteins, you're absorbing amino acids. So it's natural to talk about amino acids in the context of nutrition. - Nunh-huh 02:53, 3 August 2017 (UTC)

Note also as Looie496 explained below, and also mentioned in our complete protein article, they do not need to contain all amino acids. They only need the Essential amino acids although also in the right proportions. (Such things are relative though. If you're protein intake is significantly higher than it needs be then you may still be fine even though your proportion of one essential amino acid is lower than for an ideal profile.) Nil Einne (talk) 10:40, 3 August 2017 (UTC)

• A complete protein is one that can be used efficiently by the human body to manufacture proteins. Proteins are made of amino acids. Twenty different amino acids are used, but only nine of them are essential amino acids, meaning that they cannot be synthesized inside the body and must be obtained from food. The other 11 are non-essential. Also, some of the twenty are used much more often than others. Basically a complete protein is one that contains all the essential amino acids, in proportions that allow protein to be manufactured without running out of any of the twenty component amino acids. Looie496 (talk) 03:26, 3 August 2017 (UTC)

I had the impression you've asked a number of questions before about rice. Why you should suppose you are going to squeeze any other tiny useful morsels out of the reference desk on the topic I do not know. Google is your friend. How about consulting it or Google Scholar if you want a bit less hearsay and waffle. Dmcq (talk) 09:26, 3 August 2017 (UTC)