Repairing Things in Space

If you're on the International Space Station, chances are you may break something. How do you repair things? What kind of glue can you use?

I think most objects on the ISS are made of metal, glass, plastic or rubber. You may use Pritt to glue paper. But it can't be used on anything other than paper. Water-based white glue works well on woods. I guess there are no wooden chairs on the ISS.

Many other glues release solvents. They may be hazardous in a space station. Crazy glue has very low surface tension. It can form tiny floating droplets. I guess it is not a good idea. Rubber cement smells really bad.

Hot glue may be useful. However, they are very heavy and they may catch fire. On the other hand, they are not very strong. Epoxy glue takes much efforts to mix. This can be difficult when you're floating. -- Toytoy (talk) 15:04, 8 December 2013 (UTC)

Krazy glue (cyanoacrylate) comes in different formulations, some of which are pretty thick, and I think would be suitable. I don't know how they actually do it, though. Looie496 (talk) 15:19, 8 December 2013 (UTC)

The real answer is, by spending millions of man-hours designing parts that never break, because it's nearly impossible to repair things once they're on the ISS. Of course there are toolkits, zip-ties, replacement modules for critical pieces; but most stuff stays broken until a replacement piece arrives on the next cargo mission. Here's a NASA video about repairing a minor water-leak in a space suit: note how they keep mentioning "since last summer," because the leak didn't get fixed for months. I'll see if I can find a good interview or article about the ammonia leak that happened on ISS many months ago which was actually a potential risk to astronaut safety. Nimur (talk) 15:30, 8 December 2013 (UTC)

...Here we go, repaired after Expedition 35 arrived. And, WP:WHAAOE: International Space Station maintenance. Nimur (talk) 15:33, 8 December 2013 (UTC)

(ec) Regarding epoxys, you don't need to mix them manually. They make mixing nozzles (basically a tube with a bunch of internal back and forth wiggly bits ) that go on the front of dual syringe epoxy tubes . They're not ideal for your typical junk-drawer epoxy usage, as they're single use only (the glue will set inside), but if you're in a multi-billion dollar space station in zero-G using a specially formulated epoxy, having a single-use-only dispenser isn't all that much of a drawback. -- 162.238.241.136 (talk) 15:34, 8 December 2013 (UTC)

There's also the sort of 2-part adhesives used to repair and modify circuit boards in the electronic industry. These consist of the adhesive which comes as a viscous or fairly runny liquid depend on grade, and a spray on accelerator. Proviing the applied adhesive is kept to less than about 1 mm thick, the spray on accelerant works fine. No need for manual mixing. 120.145.176.236 (talk) 00:44, 9 December 2013 (UTC)

If selecting adhesives for ISS use, I would certainly be concerned about toxic vapors, such as come from the otherwise excellent adhesive E6000. Various companies advertise adhesives for space use, which work over a wide temperature range and do not outgas beyiond strict limits, See Masterbond, Wacker adhesives, An article by someone at Masterbond notes that in low Earth orbit, atomic oxygen degrades adhesives used outside, and that cyanoacrylates are known for outgassing. The article discusses the use of various 2 part and one part epoxies in space. A distinction should be made between those to be used inside the craft and those outside, and use at high temperature versus room or low temperature, the exposure to solvents or acid, and the surface characteristics (porous or smooth). Adhesives for use outside might well be different from those to be used inside due to having to setup in vacuum and the high temperature range, as well as the UV radiation. RTV adhesive was used to hold space shuttle tiles in place, and if I recall correctly NASA had it in mind for possible in-spaced repairs. It can set up in vacuum and has a wide temperature range. Tape can also be handy. Duct tape was useful on the Apollo 13, to improvise a connection between different shaped air-handling components. It is still used in space, as is self stick Velcro, per . Gorilla Tape seems to be a superior present-day duct tape. Rescue Tape is a self-fusing silicone tape useful from -65C to 230C and resistant to a wide variety of chemicals, so useful for patching hoses. Electrical tape could be useful for repairing and insulating conductors, as would heat-shrink tubing. A small kit of tapes and adhesives could be a lifesaver. Edison (talk) 01:43, 9 December 2013 (UTC)

Mir once tested a glue which could be used to seal tiny cracks in the hull. And of course there's Pritt: "successfully tested on board the International Space Station and was awarded Space Proof Quality". I assume they keep some aboard in case a Post-it note fails suddenly... Ssscienccce (talk) 08:26, 9 December 2013 (UTC)

And the NASA website says that Rubbn’Repair and Rec’Repair are the commercial versions of technology developed through a NASA partnership for repairs on board of the ISS. Quote: "To that end, NASA funded the design of a simple and reusable patch repair system for servicing structural components in space." Ssscienccce (talk) 10:40, 9 December 2013 (UTC)

Somewhat related, at least on the subject of how hard repairs are on the ISS, I rember watching the NASA channel as they were broadcasting the installation of some mundane piece of equipment live. It was something like a metal rail on an interior wall for holding another piece of equipment. They stripped one of the screws, and then it took at least half an hour (I think more) for them to decide the best course of action to continue the installation. If they had damaged screw more, then it could have ended up stuck there and drilling out a bad screw isn't something you want to do in microgravity. — Preceding unsigned comment added by Katie Ryan A (talk • contribs) 12:54, 9 December 2013 (UTC)

I recall that Apollo 13 carried duct tape (they call it "Grey Tape") which was the key to solving their famous air filter problem. Velcro is also used for some repairs. The ISS evidently has a sufficient supply of both.SteveBaker (talk) 15:15, 9 December 2013 (UTC)

Talking of 'quick' repairs, I have never seen the ISS astronauts on the televised down links -chewing gum – that ubiquitous substance that can pug almost any leak and stick all most anything together, on everything from the Enola Gay to a nuclear submarine. What has NASA got against chewing gum. It served the military so well for the last half of the century? NASA spent millions developing a pen that could write in space and the Russian's used a pencil. At least Chris Hadfield had the sense to take up an acoustic, sans tremolo arm nor wah-wah. --Aspro (talk) 17:48, 9 December 2013 (UTC)

That story about NASA spending millions on the space pen is complete and utter nonsense. The company that developed the pen had already spent the money doing the development of a very robust pen that would write upside-down, with no intention of them ever being used in space. NASA came along several years later and bought 400 of these already-on-sale pens at below normal retail price (less than $3 each - which isn't bad for a luxury pen!) The Russians (just like any other sane space-going people) did not give out pencils to their cosmonauts because in zero g, the dust and debris from a pencil would get into delicate switches and risk shorting them out - the Russians actually bought the EXACT same pens that the NASA astronauts carried - I don't know how much they paid for them. This is a great story - but just like so many others, it's complete bullshit. SteveBaker (talk) 21:57, 9 December 2013 (UTC)

Why the hysteria SB? I linked it to a Misplaced Pages section (did I not) which begins and I quote: A common urban legend states.... Also, 3$ for a pen! You where ripped off at even 2$. A Pencil... 25 cents.--Aspro (talk) 22:22, 9 December 2013 (UTC)

You said it was true - while linking to an article that (correctly) says that it's not true. I can only conclude that you didn't read the article you linked to until I told you that you made a mistake. No hysteria - just the facts. SteveBaker (talk) 22:30, 9 December 2013 (UTC)

No way did I say it was true. I gave a lead for those that where interest to follow up (with a come-on that YOU bit at)!

Oh! An' by the way. Your bit about the dust and debris from a pencil would get into delicate switches and risk shorting them out. Let's have the last word from Chris Hadfield. Not a US citizen... -one understands- but never-the-less a commander of the International Space Station – so he must know his stuff – yeah!? Quote: One user asks why astronauts carry pencils, to which Chris replies: 'pencils work in all attitudes and pressures, good in the cockpit. Unquote . Trying to gain scientific knowledge through watching TV programs like Lost in space is not the way to go – after all, they where lost in space “Danger, Will Robinson -DANGER You are holding a pencil. If that graphite get into my circuits you will be doomed, to recording another 20 episodes.” (NASA has a channel where you can watch ISS pretty much constantly and see what their doing and what they are holding in their hands)--Aspro (talk) 23:32, 9 December 2013 (UTC)

So you expect us to believe that your editing strategy when answering questions is to write complete nonsense in the hope that this will provoke people to read your links? Either you're lying to cover your blatant mistake or you're one of the worst, most irresponsible editors we have here on the reference desks. You choose. SteveBaker (talk) 14:42, 10 December 2013 (UTC)

It is not complete nonsense. One theory as to why so meny Nobel prize winners where born and educated in Europe, is that their education system provokes students to question revived dogma. Many other people read WP Ref Desk and we don't wont to mislead them to believe every editors (not naming names) comments as the gospel truth -do we? You choose.--Aspro (talk) 17:43, 11 December 2013 (UTC)

If you'd read the article you'd linked to, you'd see that NASA was actually concerned about the exact things you just mocked Steve for describing! 75.69.10.209 (talk) 01:53, 10 December 2013 (UTC)

These were historic concerns. Like scientists of the 1800's saying a train will not be able to travel faster than 50 mph or the passengers will suffocate from not being able to breath. See my next statement.--Aspro (talk) 17:43, 11 December 2013 (UTC)

(purely speculation, but:) I assume NASA looks at very improbable risks and multiple levels of safety, potentially reconciling these statements. I certainly would not want to have to find a little piece of broken pencil lead that flies off in zero gravity, nor to absolutely guarantee that it can't possibly get crushed into a conductive layer when it gets caught in a dial as it is turned... Wnt (talk) 03:08, 10 December 2013 (UTC)

Exactly. A solid effort at improving the safety of spaceflight is to reduce every risk you can - even if it's a small one. Sure, the odds of a pencil shedding conductive material into a switch is small - but replacing a 50 cent pencil with a really high quality $3 ballpoint pen is a reasonable decision. I'd also point out that Apollo 11 nearly came to a very unfortunate end because of a broken lunar ascent motor circuit breaker - and was saved by using a pen tip to activate it. (There is some debate about whether it was one of the fancy "space pens" or just a regular felt-tip marker that did the job.) If they had taken pencils to the moon instead, there could very easily be two dead astronauts sitting on the lunar surface right now. It's no surprise then that NASA considers very carefully what goes into every gram of material we haul up into space and chooses the best option in every case. Sure, the difference between sending astronauts up with a $3 pen instead of a 50 cent pencil is small in terms of safety...but it's also negligible in terms of cost. Multiply that by the hundreds of thousands of similar decisions that they take for every mission and the results add up. Space travel is dangerous enough even with all of those careful precautions - but if they simply ignored them all, the total increase in mission risk would be appreciable.

I'd also add that for an investment of some $1,200 in "space pens" from NASA, the Fisher company who made them was able to promote the quality of that US-made pen throughout the world - they sold millions of them at a $40 to $60 price point - making tens of millions in profits - of which (presumably) a million or more was paid in taxes. This more than covered the $1,200 investment from NASA. So far from being a $1.2 million loss to the taxpayer (as the popular myth maintains), it was in fact more like a million dollar win for US taxpayers. SteveBaker (talk) 14:42, 10 December 2013 (UTC)

OK, Let use a pons asinorum: If an astronaut just floated in an aluminum can, s/he would soon suffocate in their own CO2 that they exhale. One of the soviet cosmonauts had this very problem when recommissioning one of their stations. So, orbital stations have air conditioning systems that create an air flow. That air flow brings most of the flotsam and jetsam to to air filters. The only thing that would attract this stuff to the circuitry is electrostatic force. Electronic surfaces are usually warmer than ambient, so that would repel this stuff. Also, they are coated with an electrically insulating epoxy lacquer. So any flotsam and jetsam – even iron fillings will not cause a fault. They have years to prefect this so that stray liquids, snot and stuff don't turn the lights out or worse (one can't send a repair man up at short notice to fix a problem like one can do on earth). The pencils I have seen them using on the ISS, appear to be chino-graphs – so no graphite dust problem there! Safety: A space pen cartridge is conductive and are pressurized. Of the pen and the pencil, which one offers the best failure mode? “And we've learned that the simplicity of the technology of the pencil is sometimes a more valid solution than the complexity of the highly capable, but more expensive, pressurized pen. . So therefore, let us not mislead our other readers with unsubstantiated waffle. You choose and I will object and correct -if you choose more waffle.--Aspro (talk) 17:43, 11 December 2013 (UTC)

"Genetic code" - first mentioned in which "publication" ?

Who coined the term genetic code and published it for the first time? Erwin Schrödinger ist often mentioned in this context, but he used the terms „hededitary code-script“, „chromosome code“ and „minature code“ in his documented talks in 1943 (published as a book in 1944). Crick uses it 1962 in his (documented) Nobel speech. So the reading frame is 1944-1962. When was it published first - and where? Highly appreciate your input! GEEZER 15:16, 8 December 2013 (UTC)

Google Scholar is useful for things like this, because it allows searches of the scientific literature with a restricted date range. The earliest use I find is Waddington, C. H. "The mechanism of the genetic code of development." J Genet 1941.suppl (1941): 310-311. Of course he couldn't have meant the genetic code as we now understand it, since the structure of DNA was not known at that time. (By the way, your use of the term reading frame suggests that you probably don't understand what it means.) Looie496 (talk) 15:40, 8 December 2013 (UTC)

FWIW, I took Geezer's deployment of the term to be a deliberate contextual pun. {The poster formerly known as 87.81.230.195} 90.201.159.157 (talk) 17:52, 8 December 2013 (UTC)

Although a biochemist, I admit to occasional fits silliness... Thank you very much for the Reference (and for the acquaintance with C. H. Waddington,! Very interesting fellow...)! I'll look into that. GEEZER 09:08, 9 December 2013 (UTC)

December 9

Lake Drummond

According to the article about the Great Dismal Swamp, local legends about Lake Drummond "tell of a giant firebird that made a nest of fire in the swamp that later filled with rain". Which begs the question: Is there any evidence of volcanism in the area? Because this sounds very much like the formation of a volcanic caldera. 2601:9:3200:467:5527:C9C7:A04:2CD5 (talk) 03:16, 9 December 2013 (UTC)

Not really, see Will-o'-the-wisp. Swamps produce copious amounts of combustible gases, as well as featuring creatures known to have bioluminescence. Such phenomena have been associated with swamps all over the world since time immemorial, and it probably isn't vulcanism. Read that article for some probably explanations. --Jayron32 03:37, 9 December 2013 (UTC)

I've also heard tell of haunted pirate treasure and Blackbeard's ghost...! One cannot believe every legend one hears about the Carolina coast.

That National Park Service site also says: "The beaches along Cape Hatteras National Seashore sparkle at night. When you kick the sand, you disturb tiny dinoflagellates like seasparkle, magnified in the picture to the left. A chemical reaction causes them to glow with a blue-green light." Now, that's a phenomenon to which I can personally attest! Nimur (talk) 05:33, 9 December 2013 (UTC)

Honestly that sounds a lot more like a meteorite impact to me. And in fact the trust responsible gives that explanation for its origin. Our article on Lake Drummond speaks of an underground peat fire as the explanation for the legend. It is not terribly improbable that it is based on truth, though if the lake really is 3500 years old or more, that is a most remarkable oral tradition indeed! Wnt (talk) 19:03, 9 December 2013 (UTC)

What size tree would I be ?

...if we assume I'd need the same amount of energy as a tree that I do as a human. So, around 2000 kilocalories. StuRat (talk) 05:31, 9 December 2013 (UTC)

Wow! That's a good question! And I don't see any direct answers to it either. Let's collect some back-of-envelope facts:

• We know that photosynthesis is between 0.1% to 8% efficient in converting sunlight to usable energy.
• Mean "insolation" is somewhere around 5kWh/m per day.
• A mature tree has around 200,000 leaves.
• An average leaf is about 10 square centimeters.
• One kWh is 860 kcal.
• You probably need around 2,000 kcal of food each day to survive.

So...

• The typical area of light collectors on a tree is about 200,000 x 10cm = 200m.
• Which is hit by about 200x5 = 1,000 kWh/day.
• Which produces between 0.001x1000 and 0.08x1000 = 1 to 80 kWh of useful energy per day.
• Which is between 1x860 and 80x860 = 860 and 69,000 kcal.
• Which is (amazingly) around 400 to 3,500 times 40% to 35 times as many calories as you eat over the same period!

So I think you'd be a very tiny shrub! smallish inefficient tree or an impressive hightly efficient one.

This seems wildly too high to me...but I don't see a lot of sources of error in there. Sure, some leaves shadow other leaves - but most of the light they don't absorb travels through them, so even the leaves in shadow are generating energy.

Someone please tell me where I screwed up?

SteveBaker (talk) 07:14, 9 December 2013 (UTC)

Steve, I'm not sure about your exact numbers, but your conclusion seems reasonable: you often hear similar factoids based on scientific details about how many pounds of grain it takes to make a single pound of beef, and so on. Animals - heterotrophs in general - use energy very differently from autotrophs, so it might be expected that a tree is a few orders of magnitude "more efficient." Trees also don't expend energy on locomotion, or homeostasis, and they spend very little energy on higher thought processes... there is no really good way to compare their energy budget to the energy budget of a large mammal. Nimur (talk) 07:22, 9 December 2013 (UTC)

Yes, it's hard to comprehend that a hummingbird has to eat it's entire weight every day and that an Alligator can survive for an entire year without eating. We can get by with eating around 2% of our body weight each day and are in trouble if we don't eat for a week. The hummingbird is vastly more active than we are - and the alligator is cold-blooded, has a tiny brain and spends most of it's time staying completely still. Even if we stay completely still, the demands of being warm-blooded and having a large brain that we can't turn off are large compared to most animals. SteveBaker (talk) 15:07, 9 December 2013 (UTC)

I think you missed a factor 1000 somewhere: 860 kcal isn't 400 times 2000 kcal. And you seem to have lost a zero: from 400 to 3500 is a factor 8 or 9, not 80. Ssscienccce (talk) 08:45, 9 December 2013 (UTC)

You're fine until the last line. 860/2000 = 0.4, 70,000/2000 = 3.5. So you'd probably be a tree, rather than a bush, but we'd need better estimates to determine how you range on the scale from mighty oak to sapling... MChesterMC (talk) 09:32, 9 December 2013 (UTC)

Thanks! I knew I'd gotten something wrong. I've amended the numbers and conclusion above. SteveBaker (talk) 14:56, 9 December 2013 (UTC)

35, not 3.5 . Photosynthetic efficiency is on average about 1%, which would make Stu a tree with a "solar energy capturing surface area" (isn't there a specific term for that?) of 40 to 50 m Ssscienccce (talk) 09:35, 9 December 2013 (UTC)

...and if we consider a hemispherical tree which collects sunlight on its curved surface only, this gives the Stu-tree a diameter/span of 5 to 6 m. Gandalf61 (talk) 11:23, 9 December 2013 (UTC)

• I'd bypass SteveBaker's argument entirely, and simply compare CO2 produced by respiration by a plant of a certain living mass and a (propbably resting) human over a daily period. Respiration, producing CO2 from sugar and oxygen, is the same chemical process in animals and plants, producing the same ATP output. The CO2 figures are available for plants that have been kept in darkness and their output measured. Comparing the CO2 output would give a comparison living plant mass to average adult human. Then you'd need to account for the fact that most of the wood of a tree is dead, and get an estimate for the dead to live tissue ration in whatever kind of tree you want to use. μηδείς (talk) 18:22, 9 December 2013 (UTC)

Now for the main question: What kind of tree would you be? Clarityfiend (talk) 22:32, 9 December 2013 (UTC)

Finally, someone asks the obvious question. And it's important to point out that Stu is well on his way already, as he has roots, a trunk, limbs and sometimes leaves. ←Baseball Bugs carrots→ 00:43, 10 December 2013 (UTC)

I wasn't going to get into it, but the generous assumption is an oak. The roots for the words tree and oak overlap in many languages. μηδείς (talk) 02:31, 10 December 2013 (UTC)

I don't think StuRat is one, but the only kind of tree I've ever compared anyone to is a Caucasian wingnut. Katie R (talk) 13:12, 10 December 2013 (UTC)

The biggest problem in answering this well is the wide range of efficiency numbers for photosynthesis. 0.1% to 8% is what our article says - which means there is an 80:1 size ratio between an inefficient plant that consumes 2000 calories/day and an inefficient one. That's a bigger error bar by far than the other assumptions about the area of the leaves exposed to sunlight - or the amount of sunlight available. With best assumptions for the other numbers, that efficiency range covers everything from a small tree to a really big one - so without knowing the species of tree (and finding the photosynthetic efficiency of that particular species) - we can't tell what size of tree StuRat would best compare to. Absent that information, all we can really say is that a tree of some kind is about the right comparison. You're not like a blade of grass nor like an entire forest. SteveBaker (talk) 14:10, 10 December 2013 (UTC)

Again, photosynthesis is irrelevant. Plants don't consume energy by photosynthesis, they do so by respiration, just like animals, producing CO2, just like animals. The "energy they need" is produced by respiration. μηδείς (talk) 19:21, 10 December 2013 (UTC)

I don't understand your distinction. The energy to drive the mechanisms that make up a tree need a certain amount of energy to drive them. Since trees don't absorb energy-producing chemicals - their only energy source is sunlight. They use sunlight to accumulate carbohydrates from CO2 and water during the day - which is a handy form of energy storage. They sustain themselves at night by reversing the reaction to make CO2 and water, thereby extracting energy just like animals do. But to measure JUST the energy generated from that reaction is not capturing all of the energy the plant requires. Animals consume carbohydrates and generate CO2, missing out the stage where the carbohydrates are created. So comparing the CO2 cycle energy output of a tree to the CO2 output of a human is missing out all of the energy that the trees consume for other reasons...such as building the structure of leaves, fruit, flowers and branches and that humans consume to do things like creating skin cells that we eventually shed everywhere.

Look at it this way: A plant grabs some amount of energy from sunlight. It uses this to manufacture carbohydrates. Some of the carbohydrates make trunk and leaves - while the rest is converted back into CO2 during the night. The TOTAL energy consumption is the daylight photosynthesis...and only a smaller amount is eventually involved in respiration. However, animals eat carbohydrates and convert it to CO2 without ever manufacturing the carbohydrates in the first place. Their energy intake is still not quite the same as the output because they too are creating structures as they grow and shedding hair and skin cells that took energy to create. But the balance is much closer for animals than plants. So using respiration to estimate the total energy consumption of animals is a pretty reasonable estimate - but not so for plants...and especially not for those that produce structures that animals eat (fruit, for example) or that are deliberately shed (leaves, in deciduous trees).

So, no - I don't agree with you. Photosynthesis is the only energy input that plants have - and food is the only energy input that humans have - comparing them is the correct way to answer StuRat's question. SteveBaker (talk) 22:08, 10 December 2013 (UTC)

There's no argument to be had. Addressing photosynthesis is being too clever by half. The energy a plant consumes is produced by oxidative respiration, producing CO2, H2O and ATP from sugar and O2. That's the energy a plant uses. The process is identical to that in animals, and it is a very simple matter to compare the CO2 output of an animal and a plant (kept in the dark). That the sugar a plant uses comes from photosynthesis is an interesting, but in regard to this question, entirely irrelevant fact. There's not even any direct correlation between the sugar a plant produces in a day and how much energy it uses in a day.

There are other questions, like what number of working chloroplasts of a certain output and at a certain light level would produce sufficient O2 to sustain a man, and what size plant would have that many chloroplasts. But that's not the question that's been asked. It's entirely possible Stu is interested in knowing what size tree would produce all the Oxygen and sugar he would need to survive on if he could consume its entire output, or just its excess output. Those are interesting questions too, but questions yet to be put. μηδείς (talk) 22:42, 10 December 2013 (UTC)

Another question is how much carbohydrates are stored in the plant? (i.e. how "fat" it is). A human stores many times their daily caloric intake. What is the ratio of stored to consumed sugars? --DHeyward (talk) 22:39, 11 December 2013 (UTC)

Good point. Since deciduous trees must survive for a good 6 months or so without any energy coming in, they must store at least 6 months worth of energy, although presumably they spend very little energy in winter, but there must be a large usage of energy in spring, when all the new growth begins, before there's much photosynthesis possible due to a lack of large leaves. People, on the other hand, seem to only store a few weeks worth or energy, since we are near death if we don't eat for that long. StuRat (talk) 13:50, 12 December 2013 (UTC)

Mathematical model of geographical determinism

Not sure if this question shall be in science reference desk. Anyway, has anyone ever tried to build up precise mathematical models out of geographic determinism theories, like Guns, Germs and Steel (excluding models of infectous diseases)? I wasn't been able to find anything with Google, but AFAIK it seems that some of those theories should be coherent enough to be tested with computer simulations. Maybe more than one mathematical interpretation is possible, but I was surprised I wasn't able to find one with search engines.--Nickanc (talk) 09:24, 9 December 2013 (UTC)

Mathematical models require a large enough sample size, which is not really available here, with one planet, and only two to four samples, if you want to count Africa, Eurasia, Australia and the Americas. Diamond does give comparative counts of domesticated animals for the various areas. But there's not really any way to rerun history and see the results of the simulation. μηδείς (talk) 18:14, 9 December 2013 (UTC)

Certainly we can't rerun history, but maybe there could be simplified (not too simplified) models doing less precise and accurate predictions but needing less data, no? That's what I am looking for. Of course, such a mathematical construction won't be crucial in deciding whether Diamond is right or not, but if we find that some things work under some simplified models, it is a way to strengthen his arguments and, if some things fail even in a simplified environment, isnt it a way to falsify some of his arguments? That's why I thought there could be something on the topic, but maybe I am too optimistic on science predictions. Thank you!--Nickanc (talk) 21:12, 9 December 2013 (UTC)

Producing dark energy

Supposedly most of the matter in the cosmos is dark energy. Popularly, the universe has been likened to a "perpetual motion machine" that generates dark energy to fuel its expansion. Question: is there any physical reason to expect we can't produce dark energy, if we figure out what it is? And if we produce dark energy, could the reaction have any useful real-world uses like free power, antigravity, reactionless drive, warp drive, whatever? Wnt (talk) 18:54, 9 December 2013 (UTC)

Dark Energy is a misnomer. What is called dark energy is simply the cosmological term in Einstein equations. You can not use it for anything. Ruslik_Zero 19:29, 9 December 2013 (UTC)

If dark energy is just the cosmological term, does that mean that pie chart we see in the article (and everywhere else dark energy is mentioned) is meaningless? Wnt (talk) 22:33, 9 December 2013 (UTC)

It's not meaningless, but may not mean what you think it means. According to E=mc² a kilogram of dirt "contains" about 9×10 J of energy, which would be worth billions of dollars if it could be converted into electrical energy. But there are conservation laws (not of energy but of baryon number) that prevent that conversion, and if there weren't, all of the matter would have decayed long ago and we wouldn't exist to begin with. Although almost nothing is known about the dark energy, you can make a similar argument – the fact that it hasn't decayed for over 13 billion years implies that there's no easy way to convert it into something else. Even if you did find a way to catalyze the conversion, you would very likely end up releasing more of it than you wanted to, destroying life as we know it. This is similar to the problem of trying to extract stored energy from an inflated balloon when you live on the balloon. -- BenRG (talk) 10:22, 10 December 2013 (UTC)

Well not even that is known. Conservation of energy in observed systems suggests that this is not easy. Perhaps you could generate gravitational waves with wavelengths of under a millimeter in huge quantities, this may look like dark energy, but I don't know how you would do it. Normal thermal vibrations of matter would emit some but just doesn't make enough of it. Graeme Bartlett (talk) 20:00, 9 December 2013 (UTC)

Is it possible to say what would happen if you could? For example, I know that generating ordinary gravitational waves would consume real energy and therefore is a lousy path to perpetual motion. But dark energy has some really strange attributes ("negative pressure" that somehow forces space to expand, I still don't get that) ... I don't know what to expect. Wnt (talk) 22:37, 9 December 2013 (UTC)

"Negative pressure" = tension. I don't know why so many of the accounts call it negative pressure. -- BenRG (talk) 10:22, 10 December 2013 (UTC)

• Rupert Sheldrake is widely considered a quack and dark matter and dark energy are two different concepts. But science fiction author Larry Niven has a short story in his The Draco Tavern compilation about how Einstein's Constant is the result of the use of a warp drive that exploits the free potential energy of space. μηδείς (talk) 20:30, 9 December 2013 (UTC)

It took me a while to figure out that you mentioned Rupert Sheldrake because Wnt linked him in the original question. I'm still not sure why you mentioned Larry Niven. Neither of them know anything about cosmology or particle physics. -- BenRG (talk) 10:22, 10 December 2013 (UTC)

I'll lay the blame for your confusion at Wnt's feet, piping "likened" to Sheldrake indeed!. I explicitly mentioned Niven wrote a science fiction story--I assumed it was clear that was of tangential possible interest. μηδείς (talk) 19:15, 10 December 2013 (UTC)

Are we likely to be able to produce dark energy? Quite possibly, once we figure out what it actually is though I can't help but wonder if that question is like an alchemist asking if we would ever produce . Would this be a free source of energy? Probably not, everything we've see so far suggests that energy is conserved, so you're very unlikely be able to get more energy out of creating dark energy than you put in. MChesterMC (talk) 10:01, 10 December 2013 (UTC)

Dark energy is just a convenient name for a completely unknown phenomenon. We can see that there is something missing in the equations that govern the expansion of the universe - and we don't have any clue whatever as to what it is. We attach this name to it - but that in no way indicates that this really is "energy" - let alone that we could produce it, measure it, use it...whatever. So anything comment that are stronger than "We Don't Know" may be safely ignored until/unless mainstream physics and cosmology comes up with some solid evidence for what is causing the anomalous data we're seeing. SteveBaker (talk) 13:51, 10 December 2013 (UTC)

December 10

% new cases of HIV resulting from MSM globally

I found this data for the US: More than 50% of all new HIV infections occur in gay men and other men who have sex with men (MSM). This is from amFAR.

And this for the Philippines, Eighty-five percent of the new cases of HIV in the Philippines this year involve MSM.

Would like to know data on the global figures.

Thank you. — Preceding unsigned comment added by 58.69.95.234 (talk) 02:15, 10 December 2013 (UTC)

Hello! Your statement here has confused us. Are you asking us to tell you about HIV? Are you offering to provide us with information. If you have information to give us, please visit talk:HIV and offer the information there. Thank you. μηδείς (talk) 02:24, 10 December 2013 (UTC)

Sorry I removed the "you". Would like to know data on the global figures it should have said.

This publication by the UN has some statistics. I doubt you're going to find truly global numbers published anywhere, but this report has some numbers and charts for different parts of the world starting on page 22.

Hope this helps. APL (talk) 02:39, 10 December 2013 (UTC)

Thanks APL. I saw that before, but didn't find any data on this aspect. — Preceding unsigned comment added by 58.69.95.234 (talk) 03:05, 10 December 2013 (UTC)

maximum tree height

Please tell me: when I fly over a forest, trees seem to "agree" that none of them is going to tower over all the others. Would it not be advantageous for one of them to grow just a bit taller than the others in able to capture more sunlight? — Preceding unsigned comment added by 67.86.202.189 (talk) 14:53, 10 December 2013 (UTC)

Trees are not all the same height, but a given species can grow to a range of heights. Natural (fire) and artificial (lumbering) clear-cutting tends to restart forested areas at around the same time, so it's not surprising that a given area will tend to have trees of similar height. ←Baseball Bugs carrots→ 15:21, 10 December 2013 (UTC)

Sure, but there's more to it than that. There is a very strong competition for light, but biological factors (wood strength, growth rate, ability to transport water upward, etc.) limit how high any given species can get. So when you have a single dominant species in an old forest, you tend to get uniformity. But if there is a mix of species, you often see some trees rising above the canopy. Looie496 (talk) 15:34, 10 December 2013 (UTC)

A few such trees would likely have little effect on the population, but a lot of them could crowd the shorter trees out in the long run, yes? Kind of like "volunteer corn" in a soybean field. A few stalks here and there won't have any appreciable overall effect. But planting corn and beans together could impare the growth of the bean plants. ←Baseball Bugs carrots→ 15:43, 10 December 2013 (UTC)

Some trees are adapted to live under the canopy and don't try to compete with the big trees. In European woodland, we talk about the "ground layer" which has plants like bramble and bracken and tree seedlings, followed by the "shrub layer" or "mid-layer" with holly, hazel, hawthorn and saplings of the big trees that are on the way up. Finally, there's the "canopy layer" which has the crowns of the big forest trees like oak and beech. The king of the shrub layer trees is holly, which does most of its photosynthesis during the winter and early spring before the other trees get their new leaves. Alansplodge (talk) 16:05, 10 December 2013 (UTC)

The article you want is probably ecological succession and related linked articles. Matt Deres (talk) 17:48, 10 December 2013 (UTC)

• This is an open question, one that interested me as an undergrad and still fascinates me. One enigma is the dwarf pine section of the Pine Barrens (New Jersey). It's not known for sure if genetics or environment or both accounts for the fact that these pines only grow to about 6 feet while they grow to 30 or more in other places. μηδείς (talk) 19:09, 10 December 2013 (UTC)

• What you will find is there is a natural selection answer for everything, post-discovery. Very little is known a priori about what nature will select, only that what we observe has been selected. In addition, humans manipulate selections (naturally, not just advanced DNA manipulation) such as domesticated animals (broilers, dog breeds, cattle, horses, salmon, sheep, etc) and crops such as wheat, rice, oranges and corn and a lot of those selections are supported and controlled to an extent. What is harder is to take a manipulated animal or plant and predict which would survive naturally. Moreover there are animal species such as fish that don't stop growing (similar to your trees question and observation) yet we still observe limits and ranges in size for certain species. It's like the weather - we know after the storm, what drove it's entire history. Yet we lack the the ability to forecast beyond a few days. --DHeyward (talk) 14:57, 11 December 2013 (UTC)

Density of wood shop waste

Hello.

I need to design a cyclone separator to remove saw dust and wood shavings from a wood working shop. This can be designed wit applications such as http://aerosol.ees.ufl.edu/cyclone/section08.html or www.enq.ufsc.br/disci/eqa5313/cyclone.xls‎

What will the gas density or particle loading and particle size distribution be?

Thank you.Crossgrain (talk) 15:56, 10 December 2013 (UTC)

Since woodshop dust extraction systems are operated with the mass of wood dust much lower than the mass of air, as far as gas density is concerned, you can simply use the density of air.

Particle size distribution is another matter. You have not supplied sufficient information. You need to settle a number of questions that dramatically affect particle mean size and size distribution. Is the dust extraction for the general room space, or is it to be hose-connected to the dust outlets on each individual machine? Room space dust is much finer. What sort of machines? Dust generated by orbital sanders is very fine, like the flour you make cakes from. Dust generated by cross-cut sawing is typicaly 100 times more coarse. Not all shops will do both. Why do you need to design your own? For a commerical shop, or your own hobby shop? A shop with only one worker doing fine furniture work is very different to a commercial shop milling construction timberwork. I have made fine furniture as a hobby for 50 years. I have never had dust extraction - I simply don't need it with the mostly hand tool methods I use (though even hand tools generate airborn dust), and the timber I use, mostly the Australian timber Jarrah and radiata pine, are not-toxic. Woods used in some countries are toxic. In any case, operating a commercial shop with two or more people would in most countries invite prosecution for OH&S violations.

The American hobby magazine Fine Woodworking does reviews of commercial dust extraction at frequent intervals, and also have articles on selecting and installing dust extraction equipment. Their reviews are good because they cover testing methods and the particle size range expected in various situations. I suggest you search back issues over the last 2 years or so. Copies should be in the better public libraries.

I suggest you compare any calculated design you originate with typical commercial equipment to see if you are in the ballpark.

120.145.174.117 (talk) 23:14, 10 December 2013 (UTC)

Outer planets: conjunction

I have a couple of questions about the outer planets. I found this link here in Misplaced Pages on the Jupiter-Saturn conjunction page: http://geogebratube.org/student/m21235 which is a fantastic link but: 1) Is there any link in internet with a similar diagram showing conjunction positions of Uranus and Neptune as well? (with years if possible). This is a calculation I tried to make, is this statement correct?: 2) There will be a conjunction of Jupiter-Saturn-Uranus in 2260/2261, all three will then be closest to each other in a straight line together? 3) In that case above, it would be: Jupiter -> Saturn 4.5 au, Saturn -> Uranus 9.5 au (and therefore Earth -> Uranus: total 18 au)? ~~SGAst~~ — Preceding unsigned comment added by SGAst (talk • contribs) 16:27, 10 December 2013 (UTC)

Exotic yeast gut flora

I've been reading about auto-brewery syndrome and was wondering whether any other exotic yeasts have been found in gut flora, or theoretically could. I was wondering specifically whether a stomach could, however rare and unlikely; create bread, provided the right ingredients. CensoredScribe (talk) 17:20, 10 December 2013 (UTC)

It's not particularly surprising that alcohol is produced in the gut, since alcoholic fermentation is such a simple process, the components for which are available all the time (alcohol is almost certainly being produced in your gut as you read this). In contrast, bread production requires much more specific ingredients and conditions (including a relatively dry spot in which to bake). At the risk of arguing from ignorance, it seems extremely unlikely that intestines would produce anything we would recognize as bread. -- Scray (talk) 19:33, 10 December 2013 (UTC)

Especially since getting one's gut up to 425 degrees F is contraindicated by most medical professionals. --Jayron32 01:56, 11 December 2013 (UTC)

I suppose Spontaneous human combustion could be more likely in someone with auto brewery syndrome, though despite the name; none of the alleged cases have ever described a fire actually starting within the body, nor has there been a case where someone has survived such an incident. I guess there's a reason Mulder never tried to provide even the flimsiest of scientific explanations for the miracles in skeptical Sculley's religion. I mean other than the obvious answer; that such an explanation applied to Jesus would be extremely offensive to the predominately conservative audience of Fox. CensoredScribe (talk) 22:34, 11 December 2013 (UTC)

"Discovering" the obvious

This may sound like a non-ref-desk-friendly question, but I'm looking for third-party sources on the topic, not speculation.

Basically what I'm wondering is what sources have to say about how totally obvious things can remain undiscovered (or at least not widely understood) for such a long period of time. I'll give two examples:

When I was a kid, I started drawing my own bath at a pretty young age. I quickly learned that I couldn't fill the tub up to the rim, because once I got in the tub, the mass of my body would dislocate much of the water, causing the tub to overflow. This was more than a decade before I'd heard of some old dead guy named Archimedes. My "discovery" didn't take any specificially modern comprehension of how water and solid matter interact, an understanding of the principle of buoyancy, or anything of the sort. I simply observed a reaction (the tub overflowing) to something I had done (failing to account for my mass in filling the tub) and reached a simple conclusion: water takes up space as much as people do, and since two things can't be in the same place at the same time, the water is going to have to get out of the way.

Had I been alive in ancient Greece, and had I thought to mention my "discovery" to someone who realized its relevance to science, that would be my principle, not Archimedes'. Never mind that I was six when I discovered it!

The second example has to do with the anatomical blind spot. I've always been almost blind in my right eye. Put a patch over my left eye and place a book more than six inches away from my face, and I'm completely helpless trying to read what's on the page. This led to a number of interesting quirks. If I'm squinting in the sunlight, for example, I'm likely to close my right eye, regardless of which side of me the sun is on, so the visual accuity I have with my left eye remains. I also handle a bow and arrow like a left-hander, even though I'm right-handed, since I need to have my one good eye most closely aligned with the trajectory of the arrow.

Around the time I was ten, I discovered that when I closed my right eye, I could move my left eye around in such a way as to make objects in a certain position disappear. What I was observing was the effect of the anatomical blind spot, the point at which the optic nerve leaves the eye, devoid of receptor cells. This is a phenomenon that somehow managed to remain unknown to scientists until 1663, when it was described by Edme Mariotte.

Now, granted, I knew nothing of optic nerves or rods or cones in the second instance, but how is it that such totally obvious things remain unnoticed by science for so long?198.86.53.67 (talk) 18:30, 10 December 2013 (UTC)

• Noticing things, baths overflow, apples fall, is different from formulating them mathematically and explaining them scientifically and publishing them. People can have intuitive grasps of things without being able to describe them explicitly. Also, there's priority. I discovered the Koch curve when I was 12. I only discovered it had been named and published--by someone else-- when I was 24. μηδείς (talk) 18:58, 10 December 2013 (UTC)

When they discovered that mummified hadrosaur a few years ago, and were so surprised by the shape of the animal, I was surprised that people were surprised: It had seemed perfectly obvious to me since I'd reconstructed hadrosaurs that way when I was about 12. — kwami (talk) 19:07, 10 December 2013 (UTC)

That's interesting. Here's a link to images of the hadrosaur. μηδείς (talk) 20:47, 10 December 2013 (UTC)

Displacement of water was known long before Archimedes. Aesop even has a fable of a crow using the principle, and crows are actually able to figure it out. What Archimedes realized was that this provided a way to distinguish between a complex shape of pure gold, and of gold adulterated with lead. That's not so obvious. — kwami (talk) 19:02, 10 December 2013 (UTC)

Science is not just noticing interesting phenomena but also methodically investigating them. The link describes how we conceive scientific method today but we also have articles History of scientific method and Timeline of the history of scientific method. Archimedes not only noticed his bath overflowing (the story goes) but also made an investigation about 250 BC to confirm his hypothesis which he stated as a general physical law, not limited to any particular bath: "Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object." Thus the scientist moves methodically from observation, to hypothesis, to testing the hypothesis, to arriving at a demonstrable explanation which has wider usefulness. This way of thinking is relatively recent in human history and a turning point is arguably the treatise Discourse on the Method by Descartes in 1637. Incidentally here is the correct article link about the eye's Optic disc (the OP has linked to "Optical disc" which is about CDs and DVDs.).84.209.89.214 (talk) 19:14, 10 December 2013 (UTC)

Some of the obvious things that people seemed to miss until recently include:

1) Plate tectonics, that is, that all the continents fit together like a jigsaw puzzle.

2) Ballistics, that a fired object follows a parabolic path. You would think they could tell this just by watching from the side as a trebuchet fired a stone, but they seemed to think the object went straight, or maybe followed a circular arc, until relatively recently.

3) Fractals (as hinted to above with the Koch Snowflake). The fractal nature of nature is quite obvious, once you know to look for it.

4) The the Earth is spherical. Anyone who has watched a ship sail away would have noticed it drop below the horizon. This only makes sense if the water is higher between us and the ship. In this case, this seems so counter-intuitive, that you can understand why people didn't want to accept it. StuRat (talk) 14:50, 11 December 2013 (UTC)

(4): I think people knew that the earth was round for much longer than modern people suspect. (3): The mathematics of Fractals were well understood for a long time - but it was impossible to comprehend how this math was important in the real world until we had fast enough computers (and especially computer graphics) to display them. When you see the Mandelbrot set and are able to zoom into it and explore it interactively, you can see things that look uncannily like fern leaves, coastlines, clouds and snowflakes and the connection to those real-world objects becomes such a visually compelling one that you're forced to ask "Why?" and discover the mechanisms of nature that result in the fractal nature of so many things. In many cases, it's the lack of tools (physical, mathematical or computational) to view these experiments in different ways that allows you to see what's "really" going on.

In the case of (1), Plate tectonics, we knew that some parts of the earth were moving relative to others because we could see earthquakes and folded mountain ridges. But only when you can see the direction that each entire plate is moving can you "put it together" and grasp the idea that these large, fairly rigid objects are obviously floating around on an underground sea of liquid. Without the data showing how small areas of the earth are moving relative to each other, all you see are little snapshots of local activity and understanding "the big picture" is extremely difficult.

In the case of ballistics (2), people clearly knew how to aim an arrow up into the air to hit a distant target - that's been known almost since the bow and arrow were first invented. Even chimpanzees and very small children with no knowledge of math, science and ballistics can toss a ball back and forth - with a precision that implies that at some level their brains and muscles understand that projectiles follow a parabolic path. But it required someone with the desire to describe it mathematically to discover what was really going on. The Greeks had the math skills and the ability to get a projectile on target - but their philosophical nature prevented them from applying one to the study of the other - so they never did "understand" what they knew full well how to do with their hands and actively used to conquer large parts of their world.

There are many other examples of this. The "chaotic" nature of the weather was only discovered when someone tried to simulate the progression of hurricanes on a computer - and decided to re-run a previous simulation by typing in the initial data a second time. Because he only typed in six significant digits instead of eight he got a WILDLY different result from his simulation - and realized that one part-per-million difference in the initial conditions could result in a 1000% difference in the results!

It's very often the case that we have everything we need to make some discovery - but it takes a small accident or some such thing to provoke a particular line of thinking that results in that discovery taking place.

A good example of this is Zipf's law - a simple mathematical relationship that seems to pop up in a lot of unexpected places (everything from the frequency at which common words are used in almost all human languages to the population sizes of our cities). We don't really know why that is...in a sense it's like chaos theory or fractals once were. We see some mathematical distribution almost everywhere we look, but we don't know why. Doubtless there are people excitedly trying to figure it out as we speak - but the catalyst for doing that wasn't some major new breakthrough, new data, new tools - it was just the happy coincidence of someone looking at some data and (as if by magic) seeing a simple relationship going on that looks as though it might explain something that's interesting.

That's not always the case - early astronomers thought they'd found a simple relationship between the sizes of the orbits of the planets and the diameters of platonic solids with the same length sides...but that turns out to be nothing more than a coincidence (and not an accurate one at that!)...but whenever something like that pops up, it's always worth looking at to see if there is something new to understand.

SteveBaker (talk) 15:37, 11 December 2013 (UTC)

We actually have an article on the spherical Earth, and the history of observations on this concept. To some extent, it's more a question of whose account was the first to be committed to permanent storage and not lost, rather than a matter of it really being discovered; the ancient Greeks definitely had it down by several lines of evidence by at least the 3rd century BC.

Worth noting is the frustrating tendency on the part of U.S. children's cartoons to suggest that Christopher Columbus' accidental discovery of 'America' was a consequence of a 'novel and controversial' belief by Columbus that the Earth was round, and that a route to the East Indies could be achieved by travelling west. In fact, the roundness of the Earth was well known and universally accepted by his fifteenth-century peers. Columbus' real new idea was based on – totally mistaken – calculations of the circumference of the Earth, which allowed him to suggest that the Earth was much smaller, and that the westward voyage would therefore be much shorter than his contemporaries believed. Columbus would have been an abject failure if the Americas hadn't interrupted his long westward sail; he was a lucky idiot. TenOfAllTrades(talk) 15:59, 11 December 2013 (UTC)

Citalopram limit

Antidepressant medication Citalopram has a warning by FDA not to exceed 40 mg daily. However, I recall reading an article saying that this limitation is overblown and is not warranted. Has anybody followed this development? I will appreciate any references? Thanks, AboutFace_22AboutFace 22 (talk) 19:46, 10 December 2013 (UTC)

Misplaced Pages (and people here at the reference desk) are required to follow "Reliable Sources" - and in this case, the FDA is amongst the top handful of most authoritative sources on the planet. So we pretty much have to go with what they say. I'm not sure where you saw these other numbers - certainly forums like StudentDoctor.net have much to say on the subject of the "STAR-D" controversy. I'm deeply concerned that people like Kevin Trudeau (a scientologist...not a scientist!) have been saying that the doses of drugs like this could be higher...which makes me even more inclined to believe the FDA! We cannot possibly endorse sources as flakey as that one! So unless someone here can come up with sources at least as reliable as the FDA, it would be irresponsible of us to say anything other than: "Listen to the FDA and ignore the crazy nut-jobs!" SteveBaker (talk) 21:32, 10 December 2013 (UTC)

Steve, as always you comment on a wide range of subjects! I believe, however that there is a flaw in your reasoning. I noticed the same problem in the pharmacist I am dealing with. FDA does not do research. What they did was: they collected literature, analyzed it and came up with this sweeping recommendation. I saw the article in question on Medscape though. It is sort of imperative for me to find it now but so far I haven't been successful. As far as I know the scientologists are opposed to all medications. Thanks, AboutFace_22AboutFace 22 (talk) 02:17, 11 December 2013 (UTC)

I absolutely agree that the FDA doesn't generally do research of their own. But that's not the point here. From a Misplaced Pages perspective...and especially on medicine-related topics (and double-especially here on the Reference Desks where there are additional restrictions in place), we prefer the kinds of sources mentioned in WP:MEDRS - which is to say "third-party" reviews of researched subjects. Specifically, our WP:MEDRS guidelines say: "Ideal sources for such content includes literature reviews or systematic reviews published in reputable medical journals, academic and professional books written by experts in the relevant field and from a respected publisher, and medical guidelines or position statements from nationally or internationally recognised expert bodies."...and clearly the FDA are amongst the latter. I'm not saying that the FDA are necessarily right - only that our answers here should be driven by their guidelines and those that are likely to come from similar 3rd party reviews of the material that's out there. Reports from single research studies are not the kinds of thing we should be discussing here. We need papers that summarize and review large numbers of studies - and organizations that report the results of such reviews...in short, the FDA. If we were to cite some single study that said that there were benefits from (say) twice the FDA recommended dose of some substance - then it's very possible that someone would follow that advice and kill themselves because of an error in the paper or a statistical mistake in it's analysis. That's why Misplaced Pages has very strict guidelines on that kind of thing, and these reference desks even more so. Which means that you're not going to get the answer you seek here unless some idiot comes along and violates our rules. SteveBaker (talk) 14:45, 11 December 2013 (UTC)

People vary tremendously in their responses to SSRIs, and usually the amount of data on toxicity for any individual member of the group is limited, so the FDA tends to err on the conservative side. Lots of people can't tolerate even the clinically recommended doses. Looie496 (talk) 02:34, 11 December 2013 (UTC)

Indeed. SteveBaker (talk) 14:45, 11 December 2013 (UTC)

I am very familiar with this subject. The confusion may result from the fact that prior to 2011-2012, the recommendations for the maximum daily dosage were higher than 40mg (I don't remember what exactly is was, and can't seem to find it now). However in 2011-2012, it was discovered that citalopram (Celexa), and the closely related escitalopram (Lexepro), could cause a dangerous heart arrhythmia (prolongation of the QT interval) in some patients. This was deemed especially dangerous for people with a condition called Long QT syndrome. It was determined that this possibility was dosage dependent and the "maximum daily dosage" of citalopram was reduced to 40mg and escitalopram to 20mg. See this FDA article for further information.--William Thweatt 16:31, 11 December 2013 (UTC)

Thanks everyone for all contributions although everything that's been said here is familiar to me. It is sort of daily routine but still I hoped that there might be a loophole. The issue frankly was not an attempt to increase the dosage of citalopram but to combine it with quetiapine which does have a modest (0.17) gravity toward QT prolongation. AboutFace_22AboutFace 22 (talk) 02:20, 12 December 2013 (UTC)

Distinguishing between wet and cold

I like my washing to be dry when I put it away but (given the low temperature of the region where I live at this time of year) I am unable to distinguish between cold and wet using my hands. Is this the same for everyone? --78.148.110.243 (talk) 19:55, 10 December 2013 (UTC)

Actually, never mind. I googled with a different string and found Misplaced Pages:Reference_desk/Archives/Science/2009_January_18#wet_vs._cold --78.148.110.243 (talk) 19:59, 10 December 2013 (UTC)

Oh wow...that was a good thread! Yes, it clearly is the same for everyone...and almost 5 years later(!), I still think my explanation is a good one. It would be interesting to perform the experiment I suggested - I wish I'd remembered to do it! SteveBaker (talk) 21:44, 10 December 2013 (UTC)

If wet and cold could not be distinguished by touch they would not be distinct concepts. Hold the material until it warms in your hand, and see if it is dry or cloyingly wet. μηδείς (talk) 04:41, 11 December 2013 (UTC)

It's more that something that is both wet and a little bit cold cannot easily be distinguished from something that's dry and very cold by touch alone. "Wet" and "cold" are obviously distinct concepts because touch is not the only critical factor here. We often have separate concepts for things that we can't distinguish with our senses alone - so while your conclusion is correct, your reasoning is entirely flawed.

The difficulty arises because we have no sensors in our skin that measure wetness. All of the sense organs are safely tucked away under a layer of dead skin cells - so we can't directly measure what's happening on the surface of our skin. There is no chemical detector that senses contact with air or water. What we do have is sensors that measure the temperature just beneath the surface of the skin. So when you touch something cold, heat travels from your hand into the object, reducing the temperature beneath the skin by enough that these sensors can detect it. It's not a great system...but it's all we've got. Hence (for example) you can't easily measure the temperature of something that's around room temperature by touch alone. Metals seem cold to the touch when plastics do not - even when they are at the exact same temperature. That's because metals conduct the body heat away more efficiently than plastics do - so the temperature where our thermal sensors are drops faster when touching metals than plastics. Metals feel colder than they really are - plastics and other good insulators like wood feel warm.

Consequently, the sense is reversed when things are warmer than body temperature and metals feel hotter to the touch than wood or plastic. A metal park bench, sitting baking in Texas noon sunlight feels like it's going to burn your skin right off. A wooden park bench at the exact same ambient temperature will be quite comfortable to sit on.

It's the same thing with wet versus dry cloth. Wet cloth is a great conductor of heat - so it pulls heat from your hand and feels cold. But touching dry-but-cold cloth produces the same initial effect. The only way to detect a difference is to hold the cloth for a longer amount of time. The wet cloth will continue to conduct heat away for quite some time - until the entire volume of cloth plus water has heated up to body temperature. But the surface layers of the dry-but-cold cloth will gradually rise to body temperature and start to feel warm (although the initial feeling will be cold). The poor thermal conductivity of the material will avoid the need to heat up the entire volume before you get that warm sensation.

So the trick here is to hold the cloth for a while and see how long it takes to get warm. The faster it warms up - the drier it is. Sadly, this way of feeling doesn't seem to be hard-wired into our brains, so it takes conscious effort. Worse still, you have to judge things backwards. Grab the cloth and hold it for a while - if it feels warm after (say) ten seconds - then it was just cold (but dry). If it stays cold then it was wet (but not so cold)...exactly the reverse of what you'd expect. This also brings up a kind of observer effect - the only way to tell whether something is cold-but-not-wet is to warm it up...thereby changing the very thing you were trying to measure.

Humans are easily fooled into thinking that the sensors that are a part of our body are somehow perfect - or at least much, much better than they really are. The only perception we have of the world is through those organs - so it's easy to imagine that the world "really is" as we sense it. This is more obviously true for sight, sound, taste and smell - but we imagine that we have the ability to use touch to sense the difference between wet and dry, hot or cold, metals versus non-metals - when we really don't. We can generally infer what's going on and get some measure of that - but there are always underlying assumptions that lead us astray. When we assume that two objects are both at the same temperature - but one "feels colder" - we infer that it's a good conductor of heat and therefore must be metallic...but if they really aren't at the same temperature, then that "ability" to sense metals versus non-metals is easily fooled.

The wet versus cold problem is a "touch-illusion" - just like the "optical illusions" that can fool our eyes because of their inadequacies. Auditory illusions are less common - but they do exist - as do taste and smell illusions. For example, we imagine that the "sweetness" taste sensation implies desirable foods because that taste implies that high calorie carbohydrates are present - when in fact the sense can easily be fooled by all sorts of non-nutritious chemicals such as we employ as artificial sweeteners to make food seem more desirable - or downright lethal poisons such as the Ethylene glycol found in some car antifreezes. We've come to use our deeply flawed "sweetness" detector as a measure of food desirability - when in fact, it detects nothing of the sort! SteveBaker (talk) 14:31, 11 December 2013 (UTC)

Another way to tell if fabric is wet is by it's weight. Wet clothes will hang straight down, while dry ones will "fluff up". StuRat (talk) 14:39, 11 December 2013 (UTC)

Yes, or you could warm a bit in your hand, then see if it feels dry or still cloying to your lips of fingertips. μηδείς (talk) 18:17, 11 December 2013 (UTC)

If you live in somewhere like the northern part of Great Britain or the Great Panhandle of Canada, then the solution is to use a traditional airing cupboard. In just a few days, your smalls will be dry enough to put away in draws. --Aspro (talk) 18:25, 11 December 2013 (UTC)

Are draws the same thing as joors? μηδείς (talk) 00:23, 12 December 2013 (UTC)

I have no idea what a joor is but the word is normally spelt "drawers" in the UK. --TammyMoet (talk) 11:33, 12 December 2013 (UTC)

It's a common pronunciation of drawer in the Philadelphia area, considered a shibboleth. Dream and drink are often pronounced as if they were jream and jrink. (I am not sure how widespread the pronunciation is.) μηδείς (talk) 18:54, 12 December 2013 (UTC)

Inertial & Gravitational mass

I've been having a discussion with User:Zee99 about changes to the article on Inertia. I've read about the Brans–Dicke theory, and confess that I don't really understand it, but I've always thought that under all (other) current theories, inertial mass and gravitational mass should be exactly equivalent, even when observed from moving inertial frames. Zee99 thinks that this is not true. Which of us is correct? Dbfirs 20:56, 10 December 2013 (UTC)

I posted something at Talk:Inertia. -- BenRG (talk) 22:03, 10 December 2013 (UTC)

The idea that there is no "special" reference frame in physics is of course true. But from the perspective of useful definitions of "inertial mass" (or "rest mass" to use an old-fashioned term) - the reference frame of the object itself is a handy one to pick when defining these terms. In the frame of the object itself, inertial mass and gravitational mass are always the same - so it's convenient to just talk about "mass" - and for almost all applications of terms like "inertia", where velocities are small compared to c, we can greatly simplify the discussions by simply discussing "mass". That's important here because we need to make this article approachable to "ordinary" people for whom relativity is largely irrelevant and knowing why their big-assed SUV is going to crush my Mini Cooper like a bug is something they really should understand! (cross-posted at Talk:Inertia) SteveBaker (talk) 15:00, 11 December 2013 (UTC)

I agree that the discussion of relativistic observations of mass is probably not needed in this basic article, and I would be happy to remove all the recent additions. I still think that, even when a body is moving past at close to the speed of light, the inertial mass (as measured by the force required to accelerate it) and the gravitational mass (as measured by how it affects adjacent masses) will still remain the same (since kinetic energy also has a gravitational effect). Do we have an article that discusses this? Dbfirs 17:05, 11 December 2013 (UTC)

December 11

Programming in non-computer science/software dev degrees

Programming skills seem to be creeping in into a lot of degrees that didn't use to require them or are connected to computer sci, like business, economics or biology. Is programming turning into a basic requirement in the academic landscape? Something like learning English if you are into IT, business or natural science. OsmanRF34 (talk) 01:58, 11 December 2013 (UTC)

I would say that learning to write macros is very common; learning to use scripting languages like Python or Matlab is pretty common; learning to use full-fledged programming languages like C or Java is not so common. I wish it was more common, actually -- there are lots of philosophers and biologists who would benefit from an understanding of programming. Looie496 (talk) 02:29, 11 December 2013 (UTC)

Maybe even less. Biologists don't need to learn Tex or Latex anymore to publish. --DHeyward (talk) 06:06, 11 December 2013 (UTC)

Has it ever been common for biologists? My impression is that Tex/LaTex has never been particularly common there, except perhaps for those that are maths heavy. Although I admit my knowledge is limited before the mid 90s or in the book publishing area (compared to thesis/dissertation and journal article ones). Nil Einne (talk) 13:47, 12 December 2013 (UTC)

There is a strong movement to suggest that learning at least the basics of programming should be taught in all degree-level courses - and perhaps even in high school. There are several reasons for this - one is that being able to program a computer (even in the simplest possible way) unlocks the other 95% of what a computer can do for you - because without that, you're using maybe 5% of the capability you have in your computer, tablet or cellphone. Another reason is that for children and teenagers, learning math seems "pointless" because it's so abstract and (seemingly) without real-world application. But when you get them interested in programming, they'll soon find that they want to learn math as a way to get more out of their growing programming skills. Even if people never actually use their programming skills later in life - knowing what's going on under the hood of these computers that are absolutely everywhere in our lives these days seems like a worthy activity.

The world has changed drastically over the last 20 or so years - and in one way in particular, human minds need to adapt to. When I was in school, it was essential to cram facts into kid's heads because if you needed a fact in later life and it wasn't in your head, you'd have to resort to a trek to the local library and a protracted search to find it. These days, there are three million pages of facts here on Misplaced Pages alone - and you can often find a fact faster here than digging it out of your own memory! What brains are now called upon to do is learn procedures - ways of doing things. Meta-knowledge, the understanding of how to find facts. We need to be able to do 'synthesis' - to take a bunch of facts and combine them into the results we need. A classic example is the question (above) about what size of plant consumes the same amount of energy as a human being. There is no "knowledge" that will tell you the answer to that question. It can only come about from a combination of knowledge search skills and the ability to take facts that you can easily find and combine them (using skills like critical thinking, math and programming) to produce an answer.

These days, teaching facts (beyond the most basic) is quite pointless. Making kids memorize the dates of battles and the death of kings is tantamount to child abuse! What they need are mental and physical skills - math, programming, critical thinking, logic, search-engine skills, music composition, literacy - both input (reading) and output (writing), communication skills, graphic design....and physical skills - things like welding, 3D printing, CAD that allow you to use modern tools to make things.

As to precisely what programming language is taught, I don't think it matters. C++ is a hard thing to learn, brutal, vicious, hard to write and hard to debug...but the ultimate in speed and power. So I don't think I'd want to teach it to non-Computer Science specialists. But Javascript, certainly.

SteveBaker (talk) 13:27, 11 December 2013 (UTC)

I agree with a lot of that, but I don't agree that learning facts has become pointless. It's impossible to understand the significance of information without facts to put it in context. How is a person who doesn't know any non-basic facts going to understand the significance of the fact that Barack Obama shook hands with Raul Castro at Nelson Mandela's funeral? Looie496 (talk) 16:11, 11 December 2013 (UTC)

That's an excellent example of what I'm saying. I was never taught a thing about Raul Castro in school or college - I'm fairly sure that nobody else who graduated more than 6 years ago has either. With what I was taught in school and (more importantly) what I'd learned from being a voracious reader and news-hound, I was puzzled as to why the news reports seemed upset at how Obama shook hands with a man who "has blood on his hands". That puzzled me because all I'd learned about him was that he took power from his brother fairly recently and has been a fairly benevolent dictator ever since. My assumption (from what I'd learned or been taught) was that there shouldn't be a reason for Obama not to shake his hand. In the past, I'd have been 100% dependent on news reporters to tell me about him - and quite honestly, I'd have been none-the-wiser. But now we have: articles on Raul Castro, Nelson Mendela and Barack Obama that tell you all of the background you need - and (specifically) that Raul fought alongside his brother through the revolution and is responsible for a lot of the same 'issues' that Fidel Castro has been labelled with. Far from being a "clean slate" and a new direction for Cuba, it now starts to look like "more of the same". But honestly, I learned nothing whatever about this subject in any formal learning situation - or even from news sources. I'm happier that I found out for myself why this handshake was or was not appropriate rather than just accepting a media sound-bite.

History classes taught me the names and dates of the kings and queens of England and numerous battles and so forth. Geography probably taught me the primary exports of Venezuala and where Bauxite is mined...but I really don't need to know any of those things - because I can trivially look them up if I ever need to know!

So what does this say about education? To me it says that it's pointless to give more than a broad-brush outline of history and geography to students who aren't planning on working in those fields - and the time that would save would be better spent in engendering the kind of curiosity that made me read the Raul Castro article when I was puzzled, the knowledge-search skills (kinda minimal in this case!) needed to find the relevant information - and also in teaching the "critical thinking" skills needed to make me wonder whether the media had just made a "knee jerk reaction" to the event - and then to interpret what I read in the context in which it matters.

Teach more skills, tools, methods and algorithms that are difficult to gain later - and fewer facts which can be recalled in half a second by asking your phone. It goes deeper than that - should you trust a fact that comes from a TV advert - or one that comes from a research paper in "Nature"? How do you know which things you're told are likely to be true? When does skepticism replace blind faith and when does trust in reliable sources shorten your search for information?

SteveBaker (talk) 16:46, 11 December 2013 (UTC)

To me that actually supports my point. Having read a whole bunch of history books, it was immediately clear to me that (a) the handshake was not an accident, and (b) that it was a signal, readable by any diplomat, that the two countries want better relations but don't want to say so explicitly. There's just no way that a superficial knowledge base and a few Misplaced Pages articles would enable anybody to figure that out. The deeper point is that the more facts you know, the more connections you can make for any new fact you encounter. Without a rich base to build on, searching only yields confusion. Looie496 (talk) 00:17, 12 December 2013 (UTC)

Yes, but the trouble is that there are too many important facts for anyone to know. Indeed, I could interpret this particular situation to a degree based on my school history lessons, but for other (equally or more important) news stories, my school knowledge provides little or no help - I was not taught economics, cryptography or information security at school, and would therefore be clueless about bitcoin, data collection by the NSA or even the entire 2008 financial crisis and associated events, without spending the time to inform myself about the above topics. Thus my contention that it is far more important to teach research skills, assessment of evidence etc. than just facts - If you have the skills you can acquire more facts pretty easily, If you only get given the facts you're stuck. Of course, teach a foundation of facts too, but that is always of secondary importance to teaching the skills. My view is also that, apart from the basics, schools don't really do a good job of deciding which facts are important and which are not so important - why is basic Latin (which I was taught in school) judged as more important than the basics of how the internet protocol works (which I most certainly wasn't taught)? I cannot come up with a single reason, except that the people deciding on the syllabus were probably humanities rather than computer science graduates. N.B, I am young enough that the internet had been around for quite a while when I was in school. Equisetum (talk | contributions) 11:47, 12 December 2013 (UTC)

Almost precisely my own view on the matter, and stated far more eloquently than I ever could. I would also add that, with the appropriate skills training (in this case research, quick reading/scanning and memorisation) it is really quite easy to gain a working collection of facts on any given subject. Therefore, if there was the requirement at some point to, say, become passingly conversant with a particular period in history, it is a far better idea to teach someone how to take a few hours to research it than to hope (usually in vain) that they will remember what they have been taught on the subject many years ago at school. Equisetum (talk | contributions) 21:25, 11 December 2013 (UTC)

Turn the clock back 40 or more years ago and we all had to be conversant with the use of a . Being able to program today is on par with being able to compute with the current technology available back then. Oh, I have my 10" Thornton in my hands now (as it seldom leaves my side) and I have not had to change the batteries, even once, even though I bought is over forty years ago. Before Windoz has had time to boot up, my Thornton have given my the answer ! Study, what ever software language the course advises you to learn. Move on from there... as the need or inclination leads you. --Aspro (talk) 18:43, 11 December 2013 (UTC)

I imagine that you must be getting on in years, which might explain why your memory isn't as reliable as it used to be—the 1950s certainly enjoyed their share of fad diets and quack nonsense. The grapefruit diet (also known as the 'Hollywood diet', and based on the notion that grapefruit contains magical weight loss enzymes) existed since at least the 1930s, and enjoyed a resurgence in the '50s. The same goes for the cabbage soup diet. The Gerson 'therapy' diet (cures cancer, migraines, and tuberculosis using organic juice, assorted supplements, and coffee enemas) originated in 1928; Gerson himself kept offering it to trusting cancer patients until he died in 1959. Johanna Budwig's Budwig protocol was published in 1952, and claimed to cure cancer with flaxseed oil and cottage cheese. Various forms of radioactive quackery flourished in the first half of the twentieth century—did you know that you could cure arthritis by lying in a box full of mildly radioactive sand? I could go on.

You're on very shaky ground if you want to pretend that your generation was better immunized against pseudoscientific nonsense than the generations who followed; bad ideas had plenty of followers then, too. In the 1950s, it was just plain harder for similarly-minded but geographically-separated individuals to connect with one another, which meant that low-popularity ideas (for good or ill) tended to have more difficulty spreading from one place to another, or across social or class boundaries. TenOfAllTrades(talk) 06:00, 12 December 2013 (UTC)

December 12

Why don't all viruses cause cancer ?

After all, they all mess with our DNA or RNA. StuRat (talk) 00:41, 12 December 2013 (UTC)

I'm pretty sure they do, or can. Carcinogen says Certain viruses such as Hepatitis B and human papilloma virus have been found to cause cancer in humans and later on Certain viruses can also act as carcinogens by interacting with DNA. Oh sorry you said all, I missed that. OK well oncovirus says The vast majority of human and animal viruses do not cause cancer, probably because of long-standing coevolution between the virus and its host. That would be part of the general phenomenon of diseases evolving to be non-fatal over time - if you're dead you can't spread the disease, so it's not adaptive to kill the host. I guess that leaves the question "how do they avoid it?".  Card Zero  (talk) 00:54, 12 December 2013 (UTC)

Yes, I had the same thought about evolution, although I'm not sure if the small portion of hosts which die from getting cancer put a significant evolutionary pressure on the virus. And yes, I'm interested in the specific cancer-causing and not-cancer-causing mechanisms of viral replication. StuRat (talk) 01:26, 12 December 2013 (UTC)

I really don't know why you would expect them to. As a general rule, anything that causes random changes to your genetic material, can also cause cancer. Most of the time, a cell that suffers the change probably doesn't become cancerous (I'm guessing a little here; maybe someone has more precise information). My guess is, most of the time, the change either has no real effect on the cell, or else it kills it. However, the few (maybe very few?) cells that do become cancerous are the ones that get noticed.

But viruses don't cause random changes; they cause a very specific set of changes directed at reproducing the virus. If, for a particular virus, that particular set of changes doesn't cause cancer, then why should the virus cause cancer? --Trovatore (talk) 01:13, 12 December 2013 (UTC)

Why are some viruses more likely to cause cancer than others ? I've never heard of the flu virus causing cancer, for example, even though it's widespread. So what do they do differently, than, say, HPV, which causes cancer fairly often ? StuRat (talk) 01:24, 12 December 2013 (UTC)

Well, let me start out by saying I'm just guessing here. But I would note that HPV, almost by definition, causes cell proliferation (warts), which I imagine is its strategy for spreading. It might be a fine balance between causing a benign tumor like a wart, and causing a malignant one. --Trovatore (talk) 01:29, 12 December 2013 (UTC)

It seems like it might have to do with the location of the infection, as HPV that causes plantar wart does not cause cancer, AFAIK. Is that the same strain of HPV ? StuRat (talk) 01:24, 12 December 2013 (UTC)

There are dozens, if not hundreds of strains of HPV, and it is quite easy to catch more than one. μηδείς (talk) 03:47, 12 December 2013 (UTC)

Many viruses do not actually alter the host cell DNA; they just use the "machinery" of the host cell to produce more virus particles. Retroviruses do actually alter the host cell DNA, though. --Dr Dima (talk) 01:30, 12 December 2013 (UTC)

Is it as simple as only retroviruses being carcinogenic then ? StuRat (talk) 01:34, 12 December 2013 (UTC)

No. Epstein-Barr or HPV cause cancer by different means (namely, by turning off some of the cell's natural tumor suppression mechanisms, as far as I remember. Not sure, though). --Dr Dima (talk) 01:44, 12 December 2013 (UTC)

You are right. I have answered this twice at length and lost the response. So, basically, there are thousands of viruses, not all related, nor all working by the same mechanism. There are hundreds of types of cancers, which simply means cell-types reproducing out of control by the normal regulatory mechanisms. Some cancers either suppress those regulatory mechanisms (HPV) or accidentally affect them. Some viruses, like HIV, which overwrites DNA, weaken the immune system, allowing normally "weak" cancers like Kaposi's Sarcoma to overwhelm it. There's not just one type of virus or cancer or mechanism, but hundreds or thousands. Asking why all viruses don't cause cancers is like asking why all bacteria don't cause sores, given that some of them do. It's a fatally broad overgeneralization. μηδείς (talk) 03:45, 12 December 2013 (UTC)

You're just saying "It's complicated, so I don't know the answer". If so, let others answer. There must be some commonalities between those viruses which are carcinogenic. If you don't know, hopefully others will. StuRat (talk) 13:39, 12 December 2013 (UTC)

Medeis's answer is actually pretty good. Looie496 (talk) 18:08, 12 December 2013 (UTC)

There's no necessary commonality between all viruses that cause cancer, because causing a cancer is not a goal of the virus's action. (Keep in mind that "cancer" is a general term covering hundreds of different types of diseases all having unregulated growth as a common factor, just like diabetes is not just one disease, but a host of syndromes of different types and causes, all having unregulated blood sugar as a common factor.)

Some viruses like HPV cause initially benign tumors. Every time cells reproduce (which is what happens when tissues grow, as they do in tumors) they acquire mutations. If, at some point, a cell acquires a mutation that turns off a major regulatory gene, voilà, cancer. Retroviruses can cause cancer if they cause a mutation in a regulatory gene when they insert their own code into the host DNA. HIV doesn't cause Kaposi's Sarcoma directly at all, but allows it to flourish by weakening the immune system. (It turns out KS is actually caused by another virus, human herpes virus 8.)

There are so many different types of viruses, and they are so diverse (they are usually considered the equivalent to a phylum, if not a kingdom, taxonomically--virus classification) it is not even known if they have just one common origin, or if they have arisen separately from differing origins--virus origins. Cancers can even be caused by simple repeated mechanical injury causing scarring, such as found in animals with harness sores. Other than the factor of unregulated growth, there's no single marker (i.e., molecule) unique to cancers not also shared by healthy tissue. The issue is indeed complicated, and admitting it is not saying we don't know the answer, it's the first step in finding the answer. μηδείς (talk) 18:43, 12 December 2013 (UTC)

Urine as a fertilizer

I have read that urine should be diluted 1/20 to be used as a fertilizer. Is it better to allow the urine to ferment first, or can it be used to full effect from the spigot? μηδείς (talk) 03:38, 12 December 2013 (UTC)

Have you read Urine? The article discusses use as a fertilizer and typical dilutions to avoid damage from the concentrated nitrogen. The nitrogen is very useful as fertilizer, but the salt content can be a negative. Edison (talk) 03:49, 12 December 2013 (UTC)

Yes, I have read it, and you seem to have ignored my question. Does letting the urine sit to ferment have any effect, positive or negative? μηδείς (talk) 04:23, 12 December 2013 (UTC)

Note that your stated dilution is way weaker than those given in the article. That's why I pointed to the article. If you're going to water the plants a lot anyway, it probably all evens out. There seems to be a tradeoff, in that fermented urine loses nitrogen as ammonia is emitted as vapor, but some "Organoponic" projects let aerobic processes operate to produce microorganisms they think are useful, per "Plant & Soil Science: Fundamentals & Applications: Fundamentals and Applications" (2010) by Rick Parker (page 182). Edison (talk) 20:21, 12 December 2013 (UTC)

Thanks, that's an interesting link. The topic came up when the last snowstorm led from discussion of purchasing a generator to what to do if you couldn't get fertilizer for the vegetable garden. I vaguely remember having read some book that recommended using fermented urine. μηδείς (talk) 20:55, 12 December 2013 (UTC)

Just remember Don't Eat the Yellow Snow Richerman (talk) 23:27, 12 December 2013 (UTC)

Softening of the brain

Can softening of the brain, by itself, cause death, or does it facilitate death by some other means? According to the report of the event in the New York Times, Richard Upjohn died of this cause, but everything I'm finding about it as a cause of death (like the Times story) is quite old, generally 19th century or earlier. I'm not particularly inclined to trust 19th-century sources on questions like this. Nyttend (talk) 04:17, 12 December 2013 (UTC)

Paresis was once referred to as "softening of the brain". ←Baseball Bugs carrots→ 07:09, 12 December 2013 (UTC)

Yikes! The brain in its normal state is already pretty soft -- something like the texture of pudding. If it got much softer, it would liquefy. Looie496 (talk) 18:02, 12 December 2013 (UTC)

What flavor of pudding does monkey brains resemble? ←Baseball Bugs carrots→ 22:14, 12 December 2013 (UTC)

Appropriate shower length

How long exactly should one stay in the shower after a normal day at work or at school? Admiral Caius (talk) 17:54, 12 December 2013 (UTC)

Five minutes and 37.34 seconds. Seriously, how do you expect to get an answer to a question like this? --Trovatore (talk) 17:58, 12 December 2013 (UTC)

Actually, the 5 minute, 37 and /₁₀₀ths of a second shower is quite standard in the West and its former colonies. In the Netherlands they have a timer set to that length by law for all home and hotel showers. There were riots in Indonesia just after Indonesian independence from the Dutch when President Sukarno tried to institute a 333/₃rd second standard. The Left supported Sukarno's rounder number, while the Right would not abide by the 4 second shortening. His second attempt to switch to the new standard in 1965 is seen as a major factor in Sukarno's 1967 overthrow. μηδείς (talk) 18:11, 12 December 2013 (UTC)

That joke was 99 and /₁₀₀ths percent pure. ←Baseball Bugs carrots→ 20:29, 12 December 2013 (UTC)

Unilever did a survey and found that 8 minutes is popular. I can't tell you whether this is morally right, but it's normal (in the UK).  Card Zero  (talk) 21:36, 12 December 2013 (UTC)

One would have thought that normality in the UK consisted in a bath, rather than a shower. Insofar as this question is capable of a serious answer, though, "until you're clean, but no longer" is the only possibility. Tevildo (talk) 21:57, 12 December 2013 (UTC)

"Until you're clean, but no longer" is as storied a principle of the Magna Carta as "a man's home is his castle". We American's assume it as an inheritance from common law. (In addition to the 8 minute shower, there're the 16-min New York Strip shower, the 24-min Texas Deluge, and the 27-min Kramer Special.) But the trend is toward the worldwide 05:37.34 standard of the Napoleonic Code. It's only a matter of time until, as with the Imperial unit system, the Anglosphere nations drop the irrational 8-or-so-minutes and adopt the metric 05:37.34 per shower douchelitre system. μηδείς (talk) 22:11, 12 December 2013 (UTC)

Medies, that apostrophe is too far below the belt for it not to be deliberate. See also decimal time. :) Tevildo (talk) 22:24, 12 December 2013 (UTC)

Hahahaha! LOL! That was for Jack's enjoyment, I really didn't expect anyone else to notice. μηδείς (talk) 22:32, 12 December 2013 (UTC)

Ahh, the essence of these things is subtilty. I would recommend a 'rediculous' at some point, which I expect to see in the dictionaries before I meet my maker. Tevildo (talk) 23:02, 12 December 2013 (UTC)

Well, getting clean is not always the sole purpose of a shower. For example, some people sing. Do you know what they sing? I didn't think so. --Trovatore (talk) 22:23, 12 December 2013 (UTC)

Beethoven's Ninth Symphony, on a good day. ←Baseball Bugs carrots→ 22:28, 12 December 2013 (UTC)

From experience, I would say that a female teenagers need to be in the shower from the moment they get home from school, until the moment they need to get dressed up for their date. Male teenagers on the other hand, seem genetically prone, to shun soap, water, shower gels and are far happier if they they liberally coat themselves and clothes in motorcycle grease, before they go out to pick up their date. So I suspect the time period you are requesting is between two hours showering (for females) and a 1/10 of a second brief glance of a shower-head for boys. --Aspro (talk) 22:02, 12 December 2013 (UTC)

On a school camp a few years ago to an area experiencing drought and subsequent water shortages, the showers had a timer which turned off the water after three minutes. To get it going again the person showering had to leave the shower booth and press a button on the wall on the other side of the bathroom. Apparently the girls organised friends to repeatedly press the button for them. The boys coped. HiLo48 (talk) 22:45, 12 December 2013 (UTC)

Blood disorders

I am looking for a definition of Philadelphia G. It was diagnosed in 1975 by a doctor in Philadelphia. It is also called ASG. Where do I look to get an accurate definition?© — Preceding unsigned comment added by 2600:1013:B007:553E:C99E:DACF:C58F:DA74 (talk) 22:59, 12 December 2013 (UTC)

See Hemoglobinopathy for what we have on the issue. Hb G-Philadelphia is redlinked from that article - I'm fairly sure that's what you're looking for. Tevildo (talk) 23:07, 12 December 2013 (UTC)

I think this might be the actual article you want. Apologies for the decidedly non-PC language. Tevildo (talk) 23:46, 12 December 2013 (UTC)