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February 4

Stephen Hawking's illness

The progress (or regress, I suppose) of the disease of typical ALS patients is well documented, so a neurologist can give a general prediction of how long a patient will live if something else doesn't kill him first. However, Stephen Hawking isn't a typical patient, considering that he's had the disease for more than half a century. Have there been any publicly announced predictions of his remaining lifespan in recent years (you get to define "recent") by reputable neurologists? All I'm finding on Google is numerous hoaxes claiming that he's already died and been replaced by some poor sap who's had to become a body double. Nyttend (talk) 05:04, 4 February 2017 (UTC)

Related question—have they studied him to determine why he's been able to live so long, with the hope of applying that knowledge to other patients? If so, what have they learned?Loraof (talk) 17:14, 4 February 2017 (UTC)

Life expectancy for ALS is in general much shorter, but his is a rare form of ALS.

From the relevant article: "Hawking has a rare early-onset, slow-progressing form of amyotrophic lateral sclerosis (ALS), commonly known as motor neurone disease in the UK, that has gradually paralysed him over the decades. He now communicates using a single cheek muscle attached to a speech-generating device."

Life expectancy can also be prolonged through better supportive care like assisted breathing machines.

--Llaanngg (talk) 01:11, 5 February 2017 (UTC)

Given the nature of his condition it seems to me that his life is most at risk from secondary effects e.g. if he gets pneumonia. Count Iblis (talk) 22:05, 5 February 2017 (UTC)

Reverse osmosis

Can water purified by reverse osmosis be considered sterile insofar as common pathogens are effectively removed? Roger (Dodger67) (talk) 05:33, 4 February 2017 (UTC)

Only if all the downstream equipment has also been effectively sterilized prior to startup. 2601:646:8E01:7E0B:8C41:94D2:B8B0:3710 (talk) 06:15, 4 February 2017 (UTC)

Drinking water in bottles, which was taken from "unselected source", filtered with reverse osmosis, I found declared to be processed with "ozone and uv light". --Hans Haase (有问题吗) 17:04, 4 February 2017 (UTC)

How small are RO membrane pores compared to bacteria or virusses? Roger (Dodger67) (talk) 19:28, 4 February 2017 (UTC)

Since they have to filter out the dissolved salts, they by definition have to be smaller than viruses. 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 09:35, 5 February 2017 (UTC)

Spectrophotometry

In UV-vis spectrophotometry, which wavelengths are the best for detection of aqueous Cu²⁺, Al³⁺/AlOH²⁺/Al(OH)₂⁺, and PO₄³⁺/HPO₄²⁺/H₂PO₄⁺? 2601:646:8E01:7E0B:8C41:94D2:B8B0:3710 (talk) 06:22, 4 February 2017 (UTC)

Anyone? 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 03:24, 8 February 2017 (UTC)

Wastewater disposal

Can anyone refer me to the current regulations for disposal of dilute, acidic aqueous waste containing (low levels of) phosphate, copper and aluminum ions? 2601:646:8E01:7E0B:8C41:94D2:B8B0:3710 (talk) 06:25, 4 February 2017 (UTC)

Identifying the correct regulations might be considered legal advice, which we aren't allowed to give. Even if it isn't, it's certainly impossible without knowing what jurisdiction's regulations you're talking about. --76.71.6.254 (talk) 07:49, 4 February 2017 (UTC)

Looking up the IP the location is as I suspected in the US, so if you just wait a while there will be no regulations on whatever waste you dispose of [1]. Dmcq (talk) 08:41, 4 February 2017 (UTC)

Any source for that claim besides notorious fake-news outlets like Vox? 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 09:36, 5 February 2017 (UTC)

Yes it is an exaggerated headline but it is essentially true, see [2], [3]. No direct help for you but it shows the way the balance on environmental protection is going. Dmcq (talk) 08:55, 8 February 2017 (UTC)

The answer is highly dependent on where you are located, who is generating the waste and how much you are generating. Assuming you are in the US you will be subject to Federal, state and potentially county laws. If you are an individual you are generally exempt from many regulations and your best bet would be to take your waste to a household hazardous waste disposal facility. If you are generating waste on behalf of a corporation or University you will need to comply with regulations such as getting an EPA ID, and paying fees to register as a hazardous materials generator Generator classes. If a hazardous waste generator such as a CESQG (see link) wishes to treat waste it becomes even more complex because you may need to submit information on exactly how you are treating the waste and provide proof that it has been rendered safe because you are now you are running a hazardous waste treatment facility. — Preceding unsigned comment added by 204.28.125.102 (talk) 01:02, 7 February 2017 (UTC)

Thanks! 2601:646:8E01:7E0B:CFC:95E:6BD7:D508 (talk) 02:37, 7 February 2017 (UTC)

Celestial body and person related to the following image

Which person and celestial body is related to the following image? Figure out the celestial body
Try to extrapolate the name of a celestial body from the images, that will lead to something that person was known for. Oh, and by the way, what's that myth about cats? Try to get a number from the first and second image (myth) to get the celestial body's name. Join that name with something related to the first image to get the thing for which the person is known. I don't know the answer, please, help. 103.253.146.245 (talk) 08:51, 4 February 2017 (UTC)

Everything there is a mammal, so the connection might be milk, with the Milky Way (or Galaxy). Graeme Bartlett (talk) 11:40, 4 February 2017 (UTC)

Just a thought: Gemini (twins) and Leo (lion, well OK so it's a cat but still) --TammyMoet (talk) 15:56, 4 February 2017 (UTC)

Leo Minor Sagittarian Milky Way (talk) 17:14, 5 February 2017 (UTC)

You might have better luck on puzzling.stackexchange.com —Tamfang (talk) 08:39, 6 February 2017 (UTC)

Why aren't opiods commonly used as suicide drugs?

In as much as I understand it, opiods typically kill (relatively) quickly by causing respiratory failure. As analgesics, I guessed that an opiod overdose would be almost painless. I'm aware that this is slightly facile: paracetamol overdose is often painful; however, paracetamol death usually occurs quite a long time after consumption when most, if not all, the analgesic effect has worn off; further, paracetamol is not known as a particularly potent analgesic.

Yet my (albeit limited) research suggests that few suicide attempts use opiods. Why not?--Leon (talk) 14:04, 4 February 2017 (UTC)

I think it is mainly an issue of availability. Opioids are all prescription drugs, and prescriptions are only supposed to be given to people who are experiencing severe pain. They aren't as a practical matter all that hard to obtain, but hard enough to reduce their use for suicide. A secondary factor is that opioids are very potent at reducing emotional distress, so a person who is able to get them might use them as a substitute for suicide. Looie496 (talk) 14:35, 4 February 2017 (UTC)

They are. They're used for analgesia in late-stage terminal conditions and, as such, it's easy to arrange an overdose that is indistinguishable from the increasing palliative dose. The most famous case is probably King George V. Andy Dingley (talk) 16:05, 4 February 2017 (UTC)

Okay, then why does the lethal injection used in the United States not use opioids? I've heard that the present procedure may be painful.--Leon (talk) 18:28, 4 February 2017 (UTC)

Most legal experts on capital punishment in the United States hold the position that for a drug or pharmaceutical to be legal for use, it must be specifically tested and regulated for a specific clinical purpose - namely, for the purpose of causing death. Few, if any, regulators and drug providers want to formally pursue the costly and emotionally-fraught steps to clinically test a fatal drug to the point where it can pass regulatory muster. It is not, in the eyes of legal scholars, sufficient to use a clinical drug that is known to be fatal in an off-label use.

Capital punishment in American law is very complicated; elements of the decision-making process are not motivated solely by scientific facts or ideologies. In other words - even if we all know that a drug can make a person die, and even if a plurality of scientists know (or believe they know) of a method to make the death painless, that does not in itself pass the muster needed to make the drug acceptable for use in cases of capital punishment.

It is primarily for this reason that there is so much debate about exactly which pharmaceuticals may be used to conduct a lethal injection: the fundamental law in our nation (the United States Constitution) mandates that the punishment must be neither "cruel" nor "unusual." Analysis of constitutional law is a matter that frequently defies a scientific world-view.

For example: in 2007, the United States Supreme Court was presented with the simple question, "Do the means for carrying out an execution cause an unnecessary risk of pain and suffering in violation of the Eighth Amendment upon a showing that readily available alternatives that pose less risk of pain and suffering could be used?"

In answer, the response was: "THE MOTION OF PETITIONERS FOR LEAVE TO PROCEED IN FORMA PAUPERIS IS GRANTED." Decipher that, you poor, brilliant scientific ethicists! Here is a brief summary, from Cornell University, to help the rest of us make sense of the decision.

Nimur (talk) 18:56, 4 February 2017 (UTC)

Opioids (note spelling) certainly can cause death, and are frequently used for (essentially) euthanasia. I have watched more than one family member in dire straits taken off to the hospice; people there die remarkably quickly while under the influence of large quantities of opioids... I think the staff have become exceedingly efficient at it. But I do not mean to blame them as they generally become involved at the stage where there is no right answer. Wnt (talk) 02:26, 5 February 2017 (UTC)

When a fly falls into water then it dies?

When a fly falls into water, then it can't move because of Van der Waals force? After how long does it die? I'm asking it because I saw on youtube a video about "miracle" in which a 'dead fly' was taken out of water when it dies and some people put on it ash and then it was revived. I don't believe it and that's why I'm looking for the scientific explanation behind it.93.126.88.30 (talk) 18:30, 4 February 2017 (UTC)

Flies are an insect and require oxygen to live. See Respiratory system of insects - Insects do not have lungs, rather, they have a series of tubes called spiracles which start as openings on the body surface and them permeate the animal's deeper tissues. I suspect that when a fly lands in water, the water blocks air (containing oxygen) moving into the spiracle system and eventually kills the fly. As for how long this takes, that would depend on many factors such as the size of the fly, how healthy the fly was when it landed, and how much it struggles (which would use up oxygen more quickly. DrChrissy ^(talk) 19:06, 4 February 2017 (UTC)

I have just watched the YouTube video. The first thing I would like to say is that I find messing around with animals in this way is morally distasteful to say the least. Back to the science. Once removed, the fly might very probably have recovered with no further action. The cigarette ash might have acted in several ways. First, the warmth of the ash might have increased the metabolism of the fly which is an ectotherm. Increased metabolism would have allowed the fly to move more normally. Second, the ash might have absorbed the water from the spiracles and their openings, thereby allowing the fly to "breath" normally and recover, DrChrissy ^(talk) 19:15, 4 February 2017 (UTC)

Thank you. What about the Van der Waals force here? 93.126.88.30 (talk) 19:20, 4 February 2017 (UTC)

This is my 2 ¢ worth. Watch a flying insect trying to exit a glass window. It has a simple brain that keep trying to fly through the glass pane until it it utterly exhausted and finally sits on the sill - no longer able to move a muscle. Looks dead, one can pick it up without it giving any response. After a period of rest however, it become active again and tries to fly through the pane once more. Think, that this fly upon finding itself in a liquid some 850 time more dense than air, s/he or it just became exhausted. The ash may have soaked up the water but remember... Next: Van der Waals force. Most flying insects have either a hydrophobic outer skin or exoskeleton which repels water (otherwise they would drown when it rains). This is why soft-soap is such an effective insecticide against infestations like greenfly. Being a wetting agent it prevents spiracle respiration. Also, soft soap is made with potassium hydroxide and thus serves as plant food. Me thinks, this fly in the video just had the time to recover after being fished out. --Aspro (talk) 23:36, 4 February 2017 (UTC)

Thank you. I'm not sure I got the answer about the "Van der Waals force". In this case of the landing of the fly to the water, did "Van der Waals force" is the causer for it to be not able to go out? You've said that insects hydrophobic bodies (I thought they have just hydrophobic 'legs' but the body is not) then, what is the reason for them to not be able to get out of the water in case of landing there?93.126.88.30 (talk) 09:40, 5 February 2017 (UTC)

When you put an insect in water and limit its respiration, it can reduce its activity to survive longer. Being cold-blooded it requires very little metabolism under adverse circumstances. Since some air diffuses through the water into any air space near the insect, it is even possible that they could survive quite long periods this way, though I don't know. Putting it in cold water helps much more - you can anaesthetize insects for days in cold temperatures, then warm them up and they are as they were. The ash simply mechanically takes up some of the water, and has no other positive effect (nicotine has a very negative effect on insects, but I suppose there is little left in ash). Now as for "Van der Waals force", this is simply a matter of it being "wet", a macroscopic everyday concept we readily understand. The water adheres to the insect by dispersive forces, perhaps also by some hydrogen bonds in places.

As for the "morality" of messing with insects, I find the complaint utterly ridiculous and without any philosophical validity. Every day we consume foods that rely on our payment of farmers to spray vast areas with insecticides (the environmentalist fringe might insist on organic insecticides). There is not a Jainist here, I would guess. So why should people hesitate to torment insects by ones and twos for intellectual curiosity when they torment them by countless thousands for some extra tasty morsels and food that sometimes gets thrown away? Is curiosity so disreputable? This is characteristic of all "animal rights" crusades - as a movement they are governed by appearances, by willful ignorance, by shaking down those vulnerable to racketeering, above all by coordinated bullying of whosoever acts differently than most people. They will walk past a thousand mousetraps in the supermarkets without comment but burn down a lab building because someone wants to cure cancer in a mouse model. Wnt (talk) 02:21, 5 February 2017 (UTC)

@Wnt:Please choose your words very carefully - are you suggesting I am on an "animal rights crusade"? DrChrissy ^(talk) 17:50, 5 February 2017 (UTC)

@DrChrissy: No. But even a mild sentiment favoring a certain philosophy can be evaluated in terms of where those who believe in it intensely have gone with it. Wnt (talk) 19:47, 5 February 2017 (UTC)

@Wnt: The fact that you started your reply with "No. But..." is extremely disingenuous and leads readers to confirm you are accusing me of being on an "animal rights crusade". If you are prepared to conclusively withdraw from this casting of aspersions, I will explain my position and why I made the comment I did - you might learn something from such an interaction. DrChrissy ^(talk) 20:06, 5 February 2017 (UTC)

At this point I have no idea what you mean. I know that I have no concern for the morality of tormenting a fly, and AFAICT you disagree with that position. In my mind, it is synonymous to think that messing with a certain animal is immoral, and to believe that the animal has a "right" not to be messed with. Wnt (talk) 20:19, 5 February 2017 (UTC)

And therein lies the problem - the two are not synonymous. DrChrissy ^(talk) 20:28, 5 February 2017 (UTC)

One doesn’t have to be a 'Jain' nor an animal liberationist to hear that small-quiet-voice inside that says lesser creatures are not our playthings. As a child, I was guilty of this before I could hear that voice. I put tadpoles under my microscope to see the blood corpuscles coursing through their tails. Now I feel bad about it, but not in a sentimental way. Rather it is is the awaking of moral awareness and mindful intentions that advances science. It is only through respecting our subjects under study that we can gain better knowledge. To suggest that mindless experimentation is OK is to keep to a child-like position.--Aspro (talk) 21:28, 5 February 2017 (UTC)

Very well said. When I was a child, I stamped on ladybirds when there was a plague of them one year. Why? - because I could. But we live and learn. “The greatness of a nation and its moral progress can be judged by the way its animals are treated.” ― Mahatma Gandhi. DrChrissy ^(talk) 21:46, 5 February 2017 (UTC)

A child feels bad about watching a tadpole suffer out of water; an adult repaves a back road riddled with mud puddles and does not give the thousands of tadpoles in them a second thought. To me the premise seems to be that an act is only immoral if you think about it, and since the curious (and children) are at risk of thinking, they are exceptionally wicked. I think that is a notion that animal rights supporters generally tend to hold... though they never thought about it. Wnt (talk) 14:19, 6 February 2017 (UTC)

@Wnt: Have you ever considered that people might have moral convictions towards animals, or follow a set of moral and ethical guidelines in animal experimentation that do not involve them being an "animal rights supporter"? DrChrissy ^(talk) 16:33, 6 February 2017 (UTC)

@Wnt: “premise seems to be that an act is only immoral if you think about it” . Homo sapiens means "wise man". Requires both thought and introspection etc. Some primates (including some humans) achieve this full ability and some don't. Normal distribution explains there is a spread of abilities. So, some Homo sapien individuals, are happier remaining ignorant, rather than employ their cognitive powers. So, don't think its is strange that some editors still hold this view point. --Aspro (talk) 17:53, 6 February 2017 (UTC)

Thank you. I'm not sure I got the answer about the "Van der Waals force". In this case of the landing of the fly to the water, did "Van der Waals force" is the causer for it to be not able to go out? (simply I didn't understand the meaning of the sentence "The water adheres to the insect by dispersive forces, perhaps also by some hydrogen bonds in places.") 93.126.88.30 (talk) 09:40, 5 February 2017 (UTC)

Coming back to DrChrissy's point about heat and ectotherms. The video is in Hebrew and it can get hot where this photos was taken. So people often drink chilled water. Looked it up. If most flying insects are cooled below 8 ° C they become immobile (not dead). So the fly may have just warmed back up and become active again.--Aspro (talk) 15:50, 5 February 2017 (UTC)

Van der Waals force is uninformative when used loosely as a synonym for the totality of intermolecular forces. This case concerns the wettability of a fly in water. Insects have hydrophobic surfaces characterized by greater than 90° contact angle to a water surface. Other examples of hydrophobic surfaces are the self-cleaning Lotus effect of some flowers and insect wings, and the water-walking feat of the "Jesus lizard" Basiliscus. The fly in the video does not appear ever to have sunk into the water (which could have been made fatal by adding a Detergent) and the moral objections raised against the revival experiment echo those against Nazi human experimentation at the Nuremberg Doctors' trial. Defense argument that such experiments were the only way to develop recovery treatment for e.g. downed pilots was rejected by the Tribunal. Blooteuth (talk) 16:24, 5 February 2017 (UTC)

@Blooteuth: The Van der Waals force is a combination of dipole-dipole interactions, dipole-induced dipole interactions, and mutually induced dipole interactions (London force), but not hydrogen bonding. But hydrogen bonding is rather important where hydrophilicity is concerned. I would expect the effect of detergent to be as a surfactant which enhances the wettability of small structures, such as insect tracheae, reducing the air internally available and making it much more difficult to purge the water if drying it out with ash or some other absorbent material. But I don't actually know that. Wnt (talk) 19:56, 5 February 2017 (UTC)

@Wnt: A purpose of our responses is to provide Wikipedia references for further study. The link to Van der Waals force that I provided explains what they are. The very first sentence of the link to Detergent that I also provided states "A detergent is a surfactant or a mixture of surfactants...". DrChrissy already linked to Respiratory system of insects that describes their trachae but no page exists with the name "insect tracheae". Apart the link you added (why?) to London dispersion force I can't see how your post is helpful to me(?) or to the OP. Blooteuth (talk) 00:01, 6 February 2017 (UTC)

Well, hydrogen bonding contributes to wettability but is not a Van der Waals force. Wnt (talk) 14:19, 6 February 2017 (UTC)

Not sure ash has anything to do with the recovery. I've seen flies "come back to life" after merely drying out. Of course, they weren't really dead, they simply go inactive when they deplete their oxygen supply. Just how inactive they go would be an interesting study. Do all nerve impulses stop, or merely slow down ? StuRat (talk) 16:48, 5 February 2017 (UTC)

And I am still a little bit confused about the reason that the insect stuck to the water without any ability to get out of it. In the meantime, I got here the explanation that they're cold blood and under 8° C they become immobile, then if it's the case here then it explains why the insect was stuck in the water without moving. But if I'm not mistaken I saw in the past insects that landed to liquids - includes water in the room temperature and they moved in the water by shaking their bodies back and forth but they couldn't really get out of the water and it looked like they are linked to the liquid, and that's why I thought on Van Der Wals force.93.126.88.30 (talk) 22:56, 5 February 2017 (UTC)

You are talking about many variables here. It is possible/probable that the fly would not have been able to take off directly from the water due to the forces discussed above. However, if the fly had moved around on the water surface until it bumped into the side of the glass, it would have climbed up the side of the glass, probably stayed there until it dried a little and then flown off. Do you have evidence that the water in the glass was 8° C? Signing 24 hrs later - DrChrissy ^(talk) 17:06, 7 February 2017 (UTC)

Don't have a good RS for you because my text books are all up in the attic now (am retired). But a 20 second google (which you could have done) came up with this : They are most active during the day at temperatures of 80 to 90°F and become inactive at night and at temperatures below 45°F. . Which is 7.222 degrees Celsius. Approx 8 ° C. In hot countries, water is often served up straight from the cooler at near 0 degrees Celsius. Which you can also experience too if you go on vacation or work in such places. --Aspro (talk) 23:33, 6 February 2017 (UTC)

I have been to many countries where water is available from coolers - including working for 12 years in Australia. I have to say that your stressing of "But a 20 second google (which you could have done) came up with this" is rather unwelcome. My question about the RS was directed at the IP to encourage them to go and do their own research, and I think your comment should have been directed at the same editor, not me. DrChrissy ^(talk) 00:45, 7 February 2017 (UTC)

Crossed wires? I first bought up the point about 8 ° C and was giving a generic reply to that post. If you had signed your post I would have made sure that I indented my reply after s/he. Whilst I am assured by my closest fiends friends that I am just a raving psychotic I am not in the same breath psychic (unlike my cat).--Aspro (talk) 01:33, 7 February 2017 (UTC)

Yikes - my fault for causing the crossed wires by not signing my post - apologies for that.As for psychic cats, I have 2 of them. Being rather cold in the UK at the moment, I am trying to keep heat in by closing room doors. What makes a cat immediately want to go through a closed door when it had been open 60 seconds previously! DrChrissy ^(talk) 17:06, 7 February 2017 (UTC)

Temperature of reflecting material

If we change the temperature of any body, would it change how it reflects light? I assume they would emit different amounts of heat but would they reflect light differently too?--Llaanngg (talk) 19:07, 4 February 2017 (UTC)

The most standard simple models of electromagnetic wave reflection - such as the reflection coefficient or the Fresnel equations - are not parameterized by temperature. Surely, we can extend these models to account for the actual, non-simple effects that apply to any specific real scenario; but such an extension to the model would not be universally or generally accurate. In practice, it is more likely that we would use an empirically-derived model, rather than attempting to model the effect of temperature on optical reflectivity using first principles of physics.

One of my go-to books on optics, Meyer-Arendt, Introduction to Classical and Modern Optics, contains entire chapters devoted to discussing reflectivity; but "temperature" is never mentioned. Loads of other parameters are described - angle of incidence, index of refraction, and (...I mean, this book is really thorough!) even esoteric optical effects like metallic extinction. But temperature is never mentioned and isn't even in the book's index. Clearly, experts in the field of optical physics do not consider temperature to be a primary factor for most classical and modern models of optical reflectivity.

Nimur (talk) 19:19, 4 February 2017 (UTC)

For the interested readers who want to learn more about extinction, we have articles on minerological extinction, but none on metallic extinction! Once again, we reference-desk regulars have located, and then crossed, the exact boundary of all the human knowledge that is documented on the internet! Nimur (talk) 19:32, 4 February 2017 (UTC)

Some materials are thermochromic and change colour when heated or cooled. In the infrared spectrum there can be significant changes dependent on temperature, but this is also where you get the black body radiation. Graeme Bartlett (talk) 22:40, 4 February 2017 (UTC)

In some cases high temperature will cause a surface to oxidize or boil away, degrading that nice shiny surface. And of course if a material is glowing white hot it may be difficult to measure how reflective it is; as a practical matter mirrors should be cool enough so that they don't swamp any reflected light with self-generated light. --Guy Macon (talk) 23:39, 4 February 2017 (UTC)

@Guy Macon: A reflective material shouldn't glow white hot, AFAIK - it should reflect that light internally, so to speak, and function as poorly as a blackbody as it functions well as a mirror. Wnt (talk) 19:59, 5 February 2017 (UTC)

(Slaps forehead.) Of course you are right. It could still glow, but only if the mirror is imperfect. A perfect mirror wouldn't glow at all.

Then again, in some cases the light you want to reflect is in the far infrared. As https://jwst.nasa.gov/mirrors.html says, "One further challenge is to keep Webb's mirror cold. To see the first stars and galaxies in the early Universe, astronomers have to observe the infrared light given off by them, and use a telescope and instruments optimized for this light. Because warm objects give off infrared light, or heat, if Webb's mirror was the same temperature as the Hubble Space Telescope's, the faint infrared light from distant galaxies would be lost in the infrared glow of the mirror. Thus, Webb needs to be very cold ("cryogenic"), with its mirrors at around -220 degrees C (-364 degree F).".

I would like to be able to say that I am smart enough to have been thinking of far infrared, but the truth is that I simply had a brain fart and didn't consider the fact (which of course I knew) that good mirrors are bad emitters, and vice versa (thus the phrase "black body radiation -- a black body is the opposite of a good mirror). Thanks for correcting me. --Guy Macon (talk) 03:57, 6 February 2017 (UTC)

That's a great example of why your original point really is relevant. The risk of reflected light being "swamped" depends on both the strength of the reflected light and the imperfection of the mirror. If a mirror is 99% reflective (I assume Webb's is much better) it does a great job of delivering the light ... yet if that light is less than 1% of the blackbody emission, it still gets swamped out. Wnt (talk) 14:29, 6 February 2017 (UTC)

stalled replicating DNA

joke about a roommate
The following discussion has been closed. Please do not modify it.
The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. Joke has been made, no need to discuss this i am not a student or writing a paper but i do have a serious issue i need help with. i have a stalled DNA fork replication front in and at my residence. i dont know how or where to get the help that i need. --Stuckinweirdzone (talk) 23:58, 4 February 2017 (UTC) Unhatting: this might be a question. There is a thing like a stalled DNA replication fork. --Llaanngg (talk) 02:42, 5 February 2017 (UTC) If you can explain the question, or answer it, by all means do so. I can make no sense out of it. Wnt (talk) 02:55, 5 February 2017 (UTC) It's simply a lame attempt at (nerdy) humor. It should be rehatted or removed. General Ization Talk 02:57, 5 February 2017 (UTC) The above discussion is closed. Please do not modify it. Subsequent comments should be made in a new section.

February 5

For how many times the water is dense than air?

In one place I see that the water is "water is about 850 times heavier than air" (I saw it on Wikipedia and some books) and in another place I see that the "air is 784 times less dense than water". What is the truth about the density of the water compared to the density air? 93.126.88.30 (talk) 09:45, 5 February 2017 (UTC)

Well it depends on air pressure, humidity, temperature, and altitude. There are standard conditions where water would be 844.66 times denser (25°). See Density of air which uselessly says "0.0023769 slug/(cu ft)" Graeme Bartlett (talk) 10:03, 5 February 2017 (UTC)

A Slug (mass) is about 14.6 kg. I really wouldn't want to meet a slug with that mass! Dmcq (talk) 10:28, 5 February 2017 (UTC)

That is actually about the weight of the world's largest slug - Aplysia vaccaria Wymspen (talk) 16:04, 5 February 2017 (UTC)

Wow! That really is a HUGE SLUG! I'm not certain I'm all that reassured by it being herbivorous :-) Thanks very much. Dmcq (talk) 17:15, 5 February 2017 (UTC)

• Minor nitpick: it depends only on composition, pressure and temperature; altitude does not directly matter, although of course it will change pressure (a lot), temperature (slightly) and humidity (I guess?), so density will be impacted by a change of altitude. Tigraan^{Click here to contact me} 12:18, 5 February 2017 (UTC)

Altitude matters greatly. At the top of Mt. Everest (8,848 metres or 29,029 ft above sea level) the air is about a third as dense as at sea level, while liquid water density is almost invariant. Blooteuth (talk) 16:37, 5 February 2017 (UTC)

Blooteuth misinterprets Tigraan, but really you both agree. This big effect of altitude is mostly because of the effect of pressure, with an influence also of temperature and humidity, all 3 of which tend to covary with altitude. But if you keep pressure, temperature and humidity constant (e.g. in an aeroplane), the altitude itself indeed has no direct effect on their densities relative to each other.Jmchutchinson (talk) 17:04, 5 February 2017 (UTC)

Precisely so. As an aside many people assume that moist air (i.e., containing water vapor) is more dense than dry air, when in fact it is the opposite. Shock Brigade Harvester Boris (talk) 17:45, 5 February 2017 (UTC)

On this point: Often wondered about whether a hot air balloon get most of it buoyancy by the hot air or the water vapour produced by burning the LPG. OK some might say but what about the combustion products containing heavy CO₂. Answer, The balloon already is carrying the carbon fuel. The atmospheric oxygen which gets combined with the hydrogen in the fuel (water vapour) surly provides more lift than lesser density which the hot air alone can provide. --Aspro (talk) 22:16, 5 February 2017 (UTC)

Interesting. I could turn this into a homework problem for my PBL course. You'd have to make some assumptions about how much ambient air gets entrained into the burner exhaust, etc. Shock Brigade Harvester Boris (talk) 22:22, 5 February 2017 (UTC)

Would be delighted if this can be incorporated into a PBL because at my age I can't be bothered to get my slide-rule out and do it myself. Hot air balloons are normally fueled by butane C₄H₁₀. Perfect combusted that gives the maximum amount of water vapor can easily be calculated but in reality combustion is seldom complete, so that is one unknown. Yet look at the sums, the burner is producing a lot of water vapor.--Aspro (talk) 23:13, 5 February 2017 (UTC)

Slide rule? And my kids think I'm a luddite... Shock Brigade Harvester Boris (talk) 23:53, 5 February 2017 (UTC)

Welcome to the club of luddites ;¬) But when the latest microsoft update crashes their computer or the batteries run down in their smart-phones/tablet/iPads (or whatever modern gizzomo that thet can't live without) who's going to be laughing then?!! --Aspro (talk) 22:47, 6 February 2017 (UTC)

Instead of calling it a slide rule, call it by the alternate name we used to use: "slipstick". That sounds niftier. ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:12, 8 February 2017 (UTC)

If it depends on a lot of factors, then why is it written so simply (that the density of the water is 850 times than the air) in many books, articles and on Wikipedia? I don't understand this issue why all of those sources chose this number while it depends on a lot of factors.93.126.88.30 (talk) 23:13, 5 February 2017 (UTC)

For most purposes such a value is enough. Another similar assertion is that "water boils at 100°C", which is only true for sea-level pressure on Earth, but good enough to remember as a rule of thumb; yet, scientists studying e.g. water on Mars need to know that it is not true. It is similar to a Wittgenstein's ladder: it is false, but not false enough to be preferable to complete ignorance. Tigraan^{Click here to contact me} 09:57, 6 February 2017 (UTC)

So the 850 times is the normal case? What is the normal case? Sorry I'm a little bit confused:) 93.126.88.30 (talk) 15:08, 7 February 2017 (UTC)

There is not really any "normal" but there are "Standard conditions for temperature and pressure" which it seems you can choose from, but I like the standard state of 25°C and 100000 pascals. The U.S. Standard Atmosphere assumes the air is perfectly dry, and so is unrealistic. Graeme Bartlett (talk) 22:49, 7 February 2017 (UTC)

hand sanitizer

Does normal drinking alcohol kill bacteria and fungi as well as the special hand sanitizer stuff does? If I used Smirnoff 90% Proof Vodka to wash my hands would it be as effective as Purell? — Preceding unsigned comment added by 83.239.58.162 (talk) 18:45, 5 February 2017 (UTC)

The alcohol is generally the same in both substances — it's ethanol either way. However, 90 proof is only 45% alcohol, and according to the FDA, 60-95% alcohol is required for optimum anti-microbial properties in hand sanitizer, so you'd want something more like Bacardi 151 to be on the safe side. Also, that's some very expensively distilled and aged EtOH to use for hand sanitizer ;) NorthBySouthBaranof (talk) 18:56, 5 February 2017 (UTC)

You may find this of interest. Richerman (talk) 23:18, 5 February 2017 (UTC)

While some sanitizers use isopropanol (including many hospital pads), which is more toxic, it is also often used at similar concentrations (I commonly see 70%). However, isopropyl alcohol is much more dangerous if ingested. It should also be noted that in various countries, ethanol products which are not destined as beverage are usually denatured, also making them more of a health hazard if consumed. This allows to bypass alcohol taxation, and at the same time discourages the drinking of products which may already otherwise contain ingredients not considered safe to drink. 76.10.128.192 (talk) 11:32, 8 February 2017 (UTC)

Had Abiogenesis Happened Once?

Life can originate from the non-living matter at any time simultaneously and constantly at local, regional depend upon the watershed, continental and global level if appropriate environmental condition available. This means there are possibilities that many different types of life can be arisen all over the earth instead of one type (known established form). Thus if abiogenesis can happen more than once then why we don’t see today

1- the existence of other types of life

2-disappearing transitional species/individual fully or partially developed tissues, organs, systems, and organisms in the process of evolution of the current known established form of life.2001:56A:7399:1200:D99:A16F:40C0:C96A (talk) 22:36, 5 February 2017 (UTC)EEK

Life arose under conditions very different from those that exist today. In particular there was virtually no oxygen (O2) in the atmosphere. Oxygen is necessary for many current forms of life, but it probably would have been very destructive to the earliest forms. There were other major chemical differences as well. Looie496 (talk) 22:49, 5 February 2017 (UTC)

You will find the answer to the second part of your question about transitional species here. As they say, all species are transitional as evolution is a continuos process that never ends, but the ones that are most obviously in the process of changing are the flying squirrels, walking catfish and the leaping blenny - a legless, leaping fish that lives on land. Richerman (talk) 23:56, 5 February 2017 (UTC)

Abiogenisis could have, and maybe did, happen more than once on Earth, but it didn't necessarily happen very often. It may not have happened on Earth at all, if theories of Panspermia are correct.

Once it had happened (or arrived) once, the non-living chemical raw materials for it happening again would quite likely be sources of food for the already-existing live organisms, so the chances of it happening a second time would have been reduced.

Similarly, any second, third, etc., forms of life to arise through abiogenisis (if they did) would also be likely "prey" for the form that had arisen first and had a head start on evolution.

We think life first arose around 3.8–4.1 billion years ago, but for the first 3.0–3.3 billion years it was only single celled (and to begin with may not even have had cells): such organisms do not form easily recognised fossils, and when they do they're difficult to analyse in terms of their biochemistry, so the evidence for any of them being from a second, third, etc., abiogenetic formation would be very difficult to identify even if they were, although other Hypothetical types of biochemistry have been considered.

If any organisms from an independant abiogenetic origin were alive today we would probably be able to tell from examining their biochemistry. The fact that we have been looking hard but have found none so far suggests that they are not being formed very often, if at all, today. However, the existence of an as-yet-unidentified Shadow biosphere is not impossible. {The poster formerly known as 87.81.230.195} 94.12.94.189 (talk) 02:30, 6 February 2017 (UTC)

• A modern spontaneous abiogenesis is unlikely because life is already ubiquitous, and most ecological niches are already filled by organisms that have had millions of years adapting to their conditions. Any new "cell" would likely find itself simply a convenient morsel for a more advanced heterotroph. μηδείς (talk) 02:34, 6 February 2017 (UTC)

• One possibility is that multiple abiogenesis events occurred, and some of the branches died out entirely, while others merged into current life forms. For example, the mitochondria in each of our cells has it's own genetics and reproduces independently, making it a possible separate life form that was incorporated into animal cells billions of years ago (this is just one possibility). StuRat (talk) 03:43, 6 February 2017 (UTC)

Biologists now have no doubts about the endosymbiotic origins of mitochondria from bacteria. However, they and the eukaryote host share many homologies (e.g. most of the genetic code converting nucleic acid sequences to peptides), so they (and indeed all other organisms that we know) are unambiguously NOT descendants of separate abiogenesis events. Endosymbiosis can at most be only crudely analogous of possible early symbiosis between the products of different abiogenis events. But competitive and predatory interactions seem likely to be much more predominant processes.Jmchutchinson (talk) 07:37, 6 February 2017 (UTC)

Agreed, but the evidence that one organism was incorporated into another does make it possible that two organisms from separate abiogenesis events could also have merged, probably very early in the history of life on Earth, as later "more evolved" organisms would be less likely to benefit from such a merger. StuRat (talk) 16:04, 7 February 2017 (UTC)

I may be wrong but it seems all living things are earthly due to lack of exotic element component in their bodies. Both the earth and ocean have not yet explored fully or unseen by human eye. The rest of world did not know America before 1492 so imagine the only slow mode of transportation existed was the natural land, air, water. This means the pockets of other forms of life either well settled or incomplete or early transitional species e.g. partially or fully developed tissues, organs, systems, and organisms in the process of evolution of known life may still exist or at least their impression if not completely perished by the well-established life. 2001:56A:7399:1200:F41F:EAAF:2DAB:EA49 (talk) 04:18, 6 February 2017 (UTC)EEK

You seem to have your terms all confused. Abiogenesis is simply a random assortment of chemicals happening to form the basic building blocks of life.

Abiogenesis has nothing to do with hypothetical partially developed organs. At no point where there detached spleens and free livers floating in the oceans, much as Young Earth creationists love that strawman. Eyes did not just evolve in isolation, they evolved as parts of lifeforms. Imagine a bunch of blind critters. Now, bear in mind that any creature can detect heat, which is a form of radiation, as is light. Imagine that one of the blind critters, thanks to a mutation was born with a small group of nerves able to detect light in addition to heat (like in the first part of the picture in the Evolution of the eye article). It would be better able to evade hazards as well as find food than the completely blind critters. Maybe not by much, but over many many generations it would make a serious difference. This pushes otherwise random Genetic drift until you eventually have, for the most part, critters able to tell if things are light or dark, but not necessarily the direction of said lightness and darkness. Once again, if some mutant critter is born that is able to discern the direction of light (like in the second and third pictures of the Evolution of the eye article), they would be better able to evade hazards and find food. In time, those critters with those proto-eyes would be pretty common. It's the same for the rest of the stages in the Evolution of the eye article.

Now, if you were talking about whether the "same" organ can appear multiple times (for example, some other creature unrelated to the first critter to evolve a proto-eye develops similar photoreceptive patches and starts the same chain again), that's still has nothing to do with abiogenesis. That would be Parallel evolution, which can happen.

If you are asking if we do not know for sure whether abiogenesis has occurred a second time in some part of the planet we cannot yet explore, considering that part of the reason we cannot explore those parts of the planet is that they are hostile to life, Occam's razor would have us side with "no." If you are asking if we have missed something in some part of the planet we could explore but have just missed so far -- how are we supposed to know? It is unknown, by the possible definition of your rather vague and rambling question. It would be more reasonable for me to ask you if you personally know for certain if the closest town you've never visited has a coffee shop staffed by five redheaded lesbians -- because there is the possibility that someone could ascertain that information at this moment. Ian.thomson (talk) 08:29, 6 February 2017 (UTC)

I suspect that abiogenesis, like speciation, tends to blur out if you look at it closely. We know that when species are separating there are periods when there is a broad population with subspecies and different populations with gradually increasing levels of reproductive isolation. Similarly, with abiogenesis, I assume that a close look at the beginning would leave you scratching your head trying to decide which molecules are "alive" and which are "dead", and what the boundaries of an "organism" are. Different chemical phenomena would appear to be abiogenesis-like phenomena and some would work out alliances while others would not. For example, some models of abiogenesis imagine that cell membranes arose spontaneously, and others describe an RNA world; some even talk about random proteins arising from polymerized hydrogen cyanide. These could be true and false hypotheses or they could be rival "origins of life" that all became one thing.

I am fond to think of bits of RNA tethered to a phosphate-bearing rock, including unusual nucleotides now reflected in enzyme cofactors of ancient origin, and becoming a symbiotic community, each "gene" having its place in some sort of "ecosystem" of the naked nucleic acid on the surface, whether to replicate itself and others or collect nutrients i.e. chemicals or to hold them and pass them around. There would be many copies (with poor fidelity, perhaps) of each gene, and many different activities, some beneficial, some even perhaps harmful, not all replicative. Without a cell membrane in sight, how do you say how many organisms that is, where its boundaries are, which parts of it are alive and which parts are dead, and which fundamental phenomena within it were "abiogenesis" and which were "evolution" and which were just chance?

In a sense, abiogenesis could happen today. Suppose a bacterium develops the ability to degrade a certain plastic into fatty acids. Evolution favors its spread. After a while the plastic falls out of favor and becomes scarce, but the enzyme is reversible, and the bacterium finds that secreting the plastic helps it to stick to PVC pipes and serves as a stored energy reserve its competitors can't digest. Well, looked at a certain way, you can say that an abiogenic process (i.e. some bright engineer) invented the plastic, and now the plastic has developed the ability to grow and reproduce and permanently plug up your sewage pipes. Wnt (talk) 14:44, 6 February 2017 (UTC)

• That all surviving life on Earth shares one common ancestor is proven by the fact that the genetic code is arbitrary. That is, there is no chemical necessity (from the shape of the molecules) which requires that certain DNA or RNA molecules in ribosomes code for which amino acids. The ribosomal units which tell which amino acid to add next to a protein being produced are made up of long molecules. The part of the molecule which reads the three letter RNA codon indicating which specific amino acid to grab is not close to and does not by chemical means physically determine which of the 20 or so amino acids will be attached to the growing protein string.

In other words, the part that reads the instructions is distant from and different from the part of the ribosome that builds the protein. The code is highly conserved as of necessity--otherwise the whole system will break down. But which three RNA molecules are associated to which amino acids is just a matter of chance, and the chances of a similar code arising by chance in two separate lineages is astronomically small, to the point of impossibility. μηδείς (talk) 17:02, 6 February 2017 (UTC)

It's worth noting that the genetic code is not as highly conserved as we were all taught in high school. There is some degree of variation, especially when examining mitochondrial genetic codes. Additionally, I wouldn't discount the role of horizontal gene transfer in introducing some potential for ubiquity despite variations in ancestry, though that is a bit of speculation on my part. --OuroborosCobra (talk) 17:58, 6 February 2017 (UTC)

Not as well preserved in this case means that some basal branches differ from the eukaryotes in the coding for one or two amino acids or use different acids. It's like saying that some poker decks come with jokers, not that some organisms play pinochle while others play mahjong. Statistically, the chances of convergence rather than common origin are nil. μηδείς (talk) 22:31, 6 February 2017 (UTC)

Proving we have a common ancestor does not prove it was the sole ancestor. Just as we found out eukaryotes incorporated endosymbionts, it is possible that various other abiogenetic origins of life led to organisms which now are integrated into our biology - such as cell membranes. We also should not forget that in the modern age of molecular biology, we tend to define life as stuff with DNA, and usually as DNA we can pull out with PCR. There is little real proof that some weird thing like desert varnish doesn't contain some entirely other kind of interesting, self-replicating biochemistry that we can't recognize because it doesn't contain anything at all familiar to us from "living" organisms. Wnt (talk) 23:48, 6 February 2017 (UTC)

Thanks all for your interest and replies. Although my knowledge of the evolution is very very slight but the cause of evolution is abiogenesis. No abiogenesis means no evolution. An organ doesn’t necessarily mean its kidney eye heart etc. It could be any undefined individual living thing say organ that we can imagine only which could have evolved partially or fully w.r.t (reactive) to its surrounding environment. 2001:56A:7399:1200:60C0:BCDD:A7F:24F2 (talk) 20:10, 6 February 2017 (UTC)EEK

You are not using the words organ or evolution above, IP 2001, to indicate the same evidence-based concepts scientists do, and there is no claim that RNA-based life did not arise at least once or that there were not other unimagined early self-repicating processes. There is simply evidence beyond a reasonable doubt for the common origin of all extant life. This is like saying that we know all birds alive had a common ancestor, it doesn't make any claim against long-dead organisms of which we have no evidence. μηδείς (talk) 22:31, 6 February 2017 (UTC)

Abiogenesis is not the cause of evolution, because the general principle of evolution preceded living organisms. It is a general principle by which the world works. For example, if you toss trash into a burn barrel (I know, a very backward thing to do, but it happens more often than is commonly imagined!) you'll end up with an accumulation of fireproof trash at the bottom, by a process of selection. If a hillside erodes, eventually there will be hills of resistant rock. I would suggest it is also at least technically possible that it was not even the cause of life. We can't yet completely rule out panspermia, though the space agencies are working on it - and while that may seem only to create a chicken and egg problem, if there is such a thing as panspermia we must take into account the possibility that life evolved in some gradual way from forms of life living in much hotter conditions in the early universe. It's at least conceivable that some kind of evolution links our life, continually adapting to ever colder and slower living conditions, all the way back to some kind of complex phenomenon of nuclei self-organizing in the quark-gluon plasma that filled the early cosmos... and going back even further, we see only more and more complex physics, which might have provided opportunities for life on an ever faster timescale the closer you come to the beginning. Now that seems almost infinitely improbable, but I don't think anyone knows or can know it's false, unless they can rule panspermia false, because beyond that the trail is far too convoluted to track. Wnt (talk) 00:00, 7 February 2017 (UTC)

The problem, Wnt, is that you are suggesting alternative causes with no evidence whatsoever. It makes me wonder if you were an adult when OJ's defense team suggested, with no evidence whatsoever, that his wife and Ron Goldman had actually been killed by Colombian druglords. That is what is called a positive defense and it requires that evidence be provided.

Since no such evidence was provided, Judge Ito was incompetent. He should have declared the "defense" invalid. Unless you have actual evidence of some earlier ancestors, there is simply no reason to grant your speculation the respect worthy of a wild speculation. Your speculation is beyond wild, it is entirely baseless. μηδείς (talk) 03:54, 7 February 2017 (UTC)

I don't think it is unreasonable to suggest an improbable alternative (as I admitted) to show that a theory is not a logical necessity. We have too many sidetracks open for me to argue here about how tightly a defendant should be muzzled while he is being condemned. Wnt (talk) 12:08, 7 February 2017 (UTC)

What we know about abiogenesis suggests, at least to me, that it requires conditions very far from thermal equilibrium, it cannot happen at any of the ambient conditions the Earth was in. To get to very complex molecular machines when the smaller parts would not be functional requires conditions where you can get a wild card for not getting things right, and that suggest that very low temperatures where you can freeze a system into a far from equilibrium state (we call this metastability) could have played a role. Take e.g. a comet in an elliptic orbit that brings it close to the Sun during part of its orbit. During the time it's far from the Sun you can have chemistry going on that's different from when its close to the Sun, together they can complete some catalytic cycle but it could be that there doesn't exist a single ambient environment where all parts of the cycle can be completed. So, in the beginning you could have had self-replicating cycles that take an entire orbit of the comet to complete, and the fact that far from the Sun some fragile molecules are protected from decay could have played role. Life in compartmentalized forms inside cells would have arisen later, when you get a self replicating cycle started, you'll get exponential growth which leads to evolution as explained here and here. Count Iblis (talk) 04:34, 7 February 2017 (UTC)

I may be misunderstanding you, Count Iblis, when you say ". . . abiogenesis requires conditions very far from thermal equilibrium . . . it cannot happen at any of the ambient conditions the Earth was in . . . ."

But abiogenisis is not theorised to have occurred everywhere at once on an Earth in overall thermal equilibrium. Within that overall stable state there have always been particular places where the local thermal conditions were not in equilibrium. Ambient sunlight always causes local thermal gradients, as do volcanic processes. In any case, sheer thermal inequalities are not generally considered sufficient in themselves; most researchers in the field seem to focus on chemical/ionic inequalities, often arising from various geological conditions, from which pre-living and subsequently living (bio)chemical processes could gain energy. {The poster formerly known as 87.81.230.195} 94.12.94.189 (talk) 22:26, 7 February 2017 (UTC)

Yes, I agree with this, but I think (just my personal opinion) that the research that is being done to simulate biochemistry that can take place inside comets is more likely to yield success. Count Iblis (talk) 04:06, 8 February 2017 (UTC)

concrete roads

I was reading this article[4] and noticed that they don't mention concrete roads. I see a lot of the new infrastructure using concrete roads instead of asphalt.

Could the decline of asphalt usage be explained by its obsolescence and ongoing replacement with concrete roads? ECS LIVA Z (talk) 20:39, 5 February 2017 (UTC)

According to the article, it's about money. Your average country road is asphalt, but if there's not enough money to do right by those roads, then less asphalt is purchased. Interstates, in contrast, are usually concrete. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:11, 6 February 2017 (UTC)

Were interstates ever usually asphalt? Sagittarian Milky Way (talk) 04:47, 6 February 2017 (UTC)

To my recollection, they were always concrete. But the federal government is paying for a good chunk of it. Not so with the country two-lanes. Interstate Highway standards doesn't seem to say anything about materials. But there's at least one illustration of an interstate overlaid with asphalt. ←Baseball Bugs ^{What's up, Doc?} carrots→ 10:24, 6 February 2017 (UTC)

Here's a comment on why concrete is generally used for the interstates.[5] ←Baseball Bugs ^{What's up, Doc?} carrots→ 10:31, 6 February 2017 (UTC)

Asphalt doesn't seem obsolete to me. Obligatory link: road surface. Interestingly, that article says: An asphalt concrete surface will generally be constructed for high-volume primary highways having an average annual daily traffic load greater than 1200 vehicles per day.[5] To me, high volume means 1200 vehicles per hour (although not the entire day).

It must be a regional thing. I've seen only few concrete roads in Europe: some mostly larger roads in Germany, a few in Belgium (mostly smaller country roads) and some bus lanes and cycling paths in the Netherlands, although the latter are being replaced by asphalt. Which kind of surface is used depends on many factors: money, summer heat, freeze-thaw cycles, noise, drainage, driver comfort, traffic characteristics, tree root resistance. PiusImpavidus (talk) 11:11, 6 February 2017 (UTC)

• Interstate Highway design standards are available publicly. here is the 2005 edition of the document. It does not specify what the paving material must be, merely that the road be paved. Individual states are left to their own devices to decide what to pave the roads with. Some use asphalt, some use concrete. --Jayron32 15:24, 6 February 2017 (UTC)

Cobblestones? Sagittarian Milky Way (talk) 16:09, 6 February 2017 (UTC)

Cobblestone is used in Massachusetts in exit gores. This page shows a picture of one on I-290 in the Worcester area. It is not used a paving surface for high speed travel, because even in Massachusetts, the road designers are not sadistic or stupid. --Jayron32 21:03, 6 February 2017 (UTC)

• Also see here. According to that document, 60% of the interstate system is paved with concrete, which means 40% is asphalt. --Jayron32 15:28, 6 February 2017 (UTC)

Also, see Chipseal, which in the USA is apparently mostly used for rural (low traffic density) roads. Here in New Zealand, chipseal is used extensively in urban side streets and in some arterial routes, despite being much noisier than asphalt. Several roads in Auckland were constructed in concrete during the 1920s and 30s, but concrete construction was abandoned soon after. Virtually all have been paved over with asphalt. See here for details. I'd be interested in more references; that is the only one I've been able to find. Akld guy (talk) 20:31, 6 February 2017 (UTC)

February 6

is couscous a liquid?

I was looking at liquid and wondered if couscous counts as a liquid. My gut says no but the definition says yes. 0¹⁸ (talk) 04:17, 6 February 2017 (UTC)

The definition: "A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure." OK, looks good for couscous, except what is a fluid? Well, that is, "a substance that continually deforms (flows) under an applied shear stress." Uh, check. That's basically restating the container requirement. 0¹⁸ (talk) 04:42, 6 February 2017 (UTC)

I can make couscous into a cone shape that will just stand there in the center of a container. It won't necessarily change shape to conform to the container. A liquid generally would, and I can't shape it into something else the way I can couscous. --OuroborosCobra (talk) 04:53, 6 February 2017 (UTC)

Couscous is probably best described as granular matter. There is no sharp boundary between liquids and amorphous solids with respect to how fast or how easily they need to deform under shear stress (see for example asphalt and pitch drop experiment). In non-Newtonian liquids (see oobleck for example) the situation is even more complicated. Does this help? Dr Dima (talk) 05:22, 6 February 2017 (UTC)

• Couscous will jam if you try to press it too hard or pour it from too fine a pipe, which a conventional liquid won't. Smurrayinchester 08:49, 6 February 2017 (UTC)

Pour water through a hypodermic needle. No cheating. Sagittarian Milky Way (talk) 09:19, 6 February 2017 (UTC)

You need to increase pressure to jam particulate matter, whereas capillary effects (the cause in your example) occur regardless of pressure. Tigraan^{Click here to contact me} 16:25, 6 February 2017 (UTC)

• No, definitely not. You might make a case for it being a fluid though. Most solid powders can be fluidised, if lubricated or agitated appropriately. Andy Dingley (talk) 09:24, 6 February 2017 (UTC)

The confusion here seems to be caused by the failure to recognise that (in scientific use) all liquids are fluids, but not all fluids are liquids. Wymspen (talk) 10:17, 6 February 2017 (UTC)

• A better definition of a liquid would be based on the behavior of the constituent particles (atoms, molecules, and/or ions) that make up the substance, specifically the manner in which the molecules move and are bonded to one another. Couscous is clearly a solid by that definition. That the individual pieces of couscous "flow" of a sort is really not relevant. Functionally, couscous is semolina, and as such, is nearly identical for chemical purposes, to lasagna noodles. No one would describe lasagna noodles as a liquid. When you have chunks of matter, it "flows" of a sort in the sense that the individual pieces will respond individually and will slide and slop past one another. But that is not what a liquid is. I mean, functionally, pouring couscous out of a box isn't any different than the movement of boulders in an avalanche, and those boulders aren't liquid. --Jayron32 15:20, 6 February 2017 (UTC)

Looks like we lack a link to couscous. StuRat (talk) 01:14, 7 February 2017 (UTC)

Units of Mass

It's easy to say that the units of mass are a kilogram, slug and pound but how did physicists determine/calculate the mass of an object first independently (without force and acceleration) in such units or while formulating F = ma = mg. Are force and acceleration necessary for the measurement/calculation of mass in aforementioned units? 2001:56A:7399:1200:F41F:EAAF:2DAB:EA49 (talk) 05:55, 6 February 2017 (UTC)EEK

The pound is weight, not mass as such, although we have Pound (mass) which gives some history. A balance scale won't work in a weightless environment. The force involved is gravity. The metric system is easier to understand, because everything in it is derived from the meter. ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:33, 6 February 2017 (UTC)

No; some of us were taught in school that that basic "pound" is a weight unit and not a mass unit, but that's wrong. All countries where people still use pounds have agreed to define the pound as 0.45359237 kilogram. For example, here's the relevant bit of the Weights and Measures Act in Canada. Anyway, for purposes of the question it suffices to focus on kilograms. --76.71.6.254 (talk) 11:53, 6 February 2017 (UTC)

Trovatore posted a really interesting comment when the mass-vs-weight thing came up on the science desk a few months ago: There was a guy on alt.usage.english, I think his name was Gene Nygaard or something similar, who looked into the history of the linguistic issue. If I recall correctly, he came to the conclusion that this insistence on "weight" as force as opposed to mass does not come from the physics community at all, but from the physics education community. I have not examined his evidence in detail, but this seems plausible to me. Weight-as-force is not a very fundamental quantity for physics; it's relative to the local gravitational field rather than being a property of the object. It's fundamental for certain branches of engineering, but engineers are not so picky about this sort of thing. But for physics teachers, it's very convenient to have a separate word, even somewhat arbitrarily chosen, because getting students to understand that two concepts are different is already challenging without having to use the same word for them. -165.234.252.11 (talk) 16:39, 7 February 2017 (UTC)

[ec]They didn't -- they simply defined mass so that the force an object exerts on the ground due to Earth's gravity would equal mg. 2601:646:8E01:7E0B:49DC:6C5:C30C:C726 (talk) 06:35, 6 February 2017 (UTC)

You can measure weight without knowing anything about force or acceleration, as with a balance. It just has to be relative to something else. Indeed, the entire purpose of defining units of weight was not to make measurements possible, but to make sure that they meant the same thing wherever you went. Someguy1221 (talk) 06:34, 6 February 2017 (UTC)

This method (w=mg) is only applied if the center of both the relative mass and the object whose mass is to be determined are at equal distance from center of the earth. Theoretically, precision deviates when there is difference in center-to-center distance (due to shapes) b/w masses and earth

Addendum

we know that w = mg

Left Hand Pan = Right Hand Pan

m1 g = m2 g where

g = GM/d^2 where d is the o/c distance between earth and mass m or from the center of an earth to the center of mass m

G = Gravitational constant

M = mass of gravitating object say earth

So m 1 (GM) / d1 ^2 = m 2 (GM) / d2 ^2

We get; m 1 / d1^2 = m 2 / d2^2

Although for simplicity we use d1 = d2 while in reality, it's hard to bring them equal. Lets measure the mass of earth on a very mammoth pan balance relative to platinum alloy on an imaginary celestial body. Assume the shape of mass of celestial body, an earth, and platinum alloy are spherical. Earth is on Left-Hand pan while the Mass of 5.97219e24 kilograms of platinum alloy is on the Right-Hand pan

So RH pan = LH pan therefore m1GM/ d1^2 = m2GM/d2^2

Where m1 = mass of earth, m2 = mass of platinum alloy, M = Mass of celestial body, d1 = the distance b/t the centers of earth and celestial body, d2 = the distance b/t the centers of mass of platinum alloy and celestial body

So m1/d1^2 = m2/d2^2; m1=m2 if d1=d2 but they are not because of difference in densities of earth and platinum alloy 2001:56A:7399:1200:61FD:4D40:C201:2A8F (talk) 08:11, 6 February 2017 (UTC)EEK

• It seems to me that the original question could apply to length, time etc. as well. The answer is that the original unit was defined so that such-or-such thing had a given measurement. In the (original) metric units length was measured as a multiple of the length of a meridian, in others systems it is described as a multiple of an average foot, but the conceptual idea is the same.

If we are talking specifically about mass, there is an additional trick: in theory, two concepts of "mass" overlap. Inertial mass is the constant used in Newton's second law F=ma, gravitational mass is the property used in the gravitational law F=G m_1 m_2 / d^2, and there is no reason a priori that the two should be equal. Empirically they are observed to coincide exactly (or at least within a precision that we cannot measure); see equivalence principle. Tigraan^{Click here to contact me} 10:45, 6 February 2017 (UTC)

Weighing equipment ID

Hi

The equipment in the attached photo was in a small wooden case and has been left on my desk by my boss to identify.

Does anyone have any idea what this equipment is/was used for?photo of equipment

thanks Gareth — Preceding unsigned comment added by Gpashley (talk • contribs) 12:08, 6 February 2017 (UTC)

It's a Westphal balance, see the German article de:Mohr-Westphalsche Waage for a picture. --Wrongfilter (talk) 12:26, 6 February 2017 (UTC)

The references in the Westphal balance article not only give pictures, but explain, in English, how it works. — Preceding unsigned comment added by Wymspen (talk • contribs) 14:29, 6 February 2017 (UTC)

"Exposed: How world leaders were duped into investing billions over manipulated global warming data"

I saw this news article which claims that a June 2015 article published by Science titled ‘Possible artifacts of data biases in the recent global surface warming hiatus’ was rushed to publication, used faulty data which exaggerated global warming and was timed to influence the Paris Agreement on climate change. Is there any truth to this or is this sensationalist journalism (or a little bit of both)? A Quest For Knowledge (talk) 21:24, 6 February 2017 (UTC)

Step one: find it in a reliable source. The Daily Mail is known to fabricate stories. --Guy Macon (talk) 21:51, 6 February 2017 (UTC)

See ad hominem, Guy. Even the devil can quote scripture. μηδείς (talk) 22:15, 6 February 2017 (UTC)

Questioning the validity and reliability of a source is par for the course for any person educated in research. The Daily Mail is a publication of low repute, because while they sometimes say true things, they are also known to mislead and make shit up. Guy is completely correct to ask for more reliable sources. This is not ad hominem -- the DM is no man, and when it comes to sources, their prestige, reputation and character are precisely what is being relied upon to establish reliability and authority. You may trust everything you see written on the bathroom wall, but I'll continue to view such missives with skepticism, pending reliable sources ;) SemanticMantis (talk) 23:10, 6 February 2017 (UTC)

Well, SM, Guy's thought process was, The Sun is evil, so what it quoted was false, even though the source was named. Given the Sun is People, that's the essence of ad hominem. μηδείς (talk) 00:50, 7 February 2017 (UTC)

Are you a mind reader? If not I don't see how you know what Guy Macon was thinking. And unless you're a mind reader, you seem to have came up with a strawman. It seems far more likely Guy Macon was doing what, as SemanticMantis has said, any competent person will do. Evaluate the source. If the source is known to be unreliable, then there's no reason to assume what is quoted is true. Note that this doesn't mean it's definitely false, but simply that we have no particular reason to think it's true. Therefore, unless someone can find a better source, there's not much point researching further. I could likewise claims global warming is a Chinese conspiracy. However if I don't have any actual evidence for this claim, there's zero reason for anyone to take my claim seriously, research it further etc. If you want to go further, this also seems to be a case of extraordinary claims require extraordinary evidence, so it's reasonable to assume it's probably (but not definitely) false based on the lack of any real evidence (since as said, Daily Mail isn't really evidence). Nil Einne (talk) 01:32, 7 February 2017 (UTC)

In my case, Medeis/μηδείς does not have the ability to read my mind despite multiple attempts to do so. If I had wanted to say "The Daily Mail is known to fabricate stories, thus this particular story is fabricated" (a logical fallacy) I would have said so. Instead I said "The Daily Mail is known to fabricate stories. Find the same story in a reliable secondary source so I can evaluate it". I am still waiting for that source.

The editorial at reason.com[6] (which, while openly biased towards libertarianism, does have a good reputation for accuracy and fact checking) reports what the Daily Mail claimed, but goes on to mention "a February 2016, Nature Climate Change published an article by a prominent group of researchers led by Canadian climate scientist John Fyfe" and "a new study published in Science Advances just last month by the researchers from the Berkeley Earth group", noting that "the Daily Mail article failed to mention [this] study which found that the revised NOAA temperature data are accurate." --Guy Macon (talk) 02:57, 7 February 2017 (UTC)

I would go a bit further, and say that it's also obvious on its face that the Daily Mail writer (and the editor who ran the "story") are conspicuously and woefully ignorant at best, and deliberately deceptive and inflammatory at worst. To wit, the Daily Mail's version of historical context:

"The scandal has disturbing echoes of the ‘Climategate’ affair which broke shortly before the UN climate summit in 2009, when the leak of thousands of emails between climate scientists suggested they had manipulated and hidden data."

which sounds damning indeed, as long as you don't actually complete the sentence honestly with something like ...which turned out – across at least eight independent investigations – to involve only trumped-up charges by climate change denialists, and no wrongdoing whatsoever by any scientist. If this case does have "echoes" of Climategate, it's probably not in the way that the Daily Mail really would like us to think. They nail their colors to the mast later on in the article, declaring "It's not the first time we've exposed dodgy climate data, which is why we've dubbed it: Climate Gate 2", again crucially omitting any mention that all the Climategate (1?) data was confirmed, and all the scientists exonerated.

And the outcome of the original Climategate controversy isn't hard to discover. It's in the lead of the freakin' Wikipedia article. A writer who omits that information (and presents the original Climategate controversy as representative of actual or probable wrongdoing) would have to be working very hard indeed to maintain such a high level of genuine ignorance—but is much more likely simply dishonest. TenOfAllTrades(talk) 03:48, 7 February 2017 (UTC)

The sources I've mentioned below great criticsm of the story but perhaps one of the more obvious flaws beyond the misleading claims about Climategate is the use of a misleading image comparing two graphs but using different baselines. They've since "corrected" this simply by noting one graph is offset from there other. This is criticised in many sources (including the ARSTehnica source linked below) but [7] is probably one of the simpler ones. Nil Einne (talk) 06:38, 7 February 2017 (UTC)

Ars Technica. A Quest For Knowledge (talk) 22:06, 6 February 2017 (UTC)

There are a few news sites parroting the same story, but it all goes back to one guy, Dr. Bates, crying foul play, but not really suggesting why or how, other than that they didn't follow a set of plans he was drawing up. See below for more info. SemanticMantis (talk) 22:14, 6 February 2017 (UTC)

(EC) Here is the original Science article in question [8]. Here are the 182 articles that currently cite it [9]. I can find no serious scholarly complaints about the basic data used in the paper, though there is some disagreement on how to best analyze it and what conclusions should be drawn - very minor stuff, and completely normal for the field, not at all indicative of foul play. As for the accusation "It was never subjected to NOAA’s rigorous internal evaluation process" - who cares? Internal review is not what makes science authoritative - peer review (and time) is. The fine folks at Science have given this work their approval after their own external peer review.

Note that there is no specific complaint offered by Dr. Bates, other than the data wasn't internally reviewed, and that he calls it "misleading". Normally, if a scientist has a problem with the data or conclusions drawn by another group of authors, they write a response article in that same (or sometimes a different) journal. If the editorial board finds the complaints meritorious, they publish the critique, and sometimes solicit the original authors and give them a chance to write a rebuttal. The fact that Dr. Bates offers no specific problem and seemingly has not pursued the normal channels, but instead runs to the tabloids does not paint him in a very credible light, despite his affiliation. Also, NOAA does plenty of quality control and quality assurance for every data product they offer, Dr. Bates' "internal review" is not part of that. NOAA is currently a world leader in developing and deploying QA/QC for large scale data, see e.g. here [10] for a feeling on that, or I can give further refs on that if you're interested.

So - this kerfluffle is all just days old, and good references are lacking. Seeing no serious critique in the published literature, and noting that (to the best of my knowledge) Dr. Bates has not published a critique in any scientific venue, my opinion as a scientist operating in an adjacent field is that, lacking any more credible evidence of foul play, we should continue to extend our trust in the practices in place at Science, which is probably the best scientific journal in the world, and it very rarely has any problems with any of their publications. By all means, keep your eye out for something damning, but this looks like nothing more than a disgruntled NOAA chap (who has a clear conflict of interest, by the way) who's found a receptive audience for a witch hunt. I wish my colleagues at NOAA well, this is a bad time to be a public scientist in the USA.

Finally, experts and politicians both give no undue weight to any one publication. This Karl paper was not the only one out, there were many available at the time. These two [11] [12] are also both about the "pause", were also published in 2015, and can help you understand some of the differing viewpoints on the quality of the data and how to interpret it. SemanticMantis (talk) 22:14, 6 February 2017 (UTC)

The most interesting claim is "This newspaper has learnt that NOAA has now decided that the sea dataset will have to be replaced and substantially revised just 18 months after it was issued, because it used unreliable methods which overstated the speed of warming." This is definitely a put-up-or-shut-up claim; either NOAA will revise the dataset or it won't. And scientists will look at both datasets and see if the revision is a hasty snow job by Trump appointees or actually has some reason. Until then, there's no great urgency to predict what we'll see ... we know we'll be doing absolutely nothing good about global warming no matter what. Wnt (talk) 00:15, 7 February 2017 (UTC)

This is a canonical example of a red herring. NOAA continually updates its data sets, as does every other operational center (Hadley Centre, ECMWF, etc etc). Shock Brigade Harvester Boris (talk) 01:55, 7 February 2017 (UTC)

Indeed as far as I can tell, the claim is simply referring to ERSSTv5. While the time frame between ERSSTv5 and ERSSTv4 seems a bit short (compared to ERSSTv4 vs ERSSTv3b for example) there could be various reasons for that. Notably the fact that ERSSTv5 is coming is not some shocking new discovery by the Daily Mail. It's upcoming release has been noted well before this, see e.g. this from June 2016 [13] which specifically mentions a 2017 release target. Nil Einne (talk) 02:05, 7 February 2017 (UTC)

[14] is a direct response to the Mail on Sunday story. Nil Einne (talk) 01:48, 7 February 2017 (UTC)

I tried a Google search for "Pausebuster" (which is what the Daily Mail says the "scandal" is called, although they like the term "Climategate 2" better) and I see it mentioned by Fox News, Breitbart, the Washington Times, "What's up with that," and Reason. As a rule, if a story doesn't bounce out of the echo chamber into mainstream news, then it cannot be important. Mind you, the Daily Mail reporters have made it seem pretty important. Thanks to SemanticMantis and Nil Einne for pointing out it does not really say anything. No doubt some editor will create an article which I do not think is justified unless it attracts mainstream media attention and we will have adequate sources to write an informed article. TFD (talk) 02:01, 7 February 2017 (UTC)

Another blog response this one dealing more with the processes than the science [15]. That links to [16] which also deals mostly with the science. In the interest of full disclosure, I also came across this response on Judith Curry's blog to the first blog and other things [17]. Nil Einne (talk) 02:09, 7 February 2017 (UTC)

Note that you can tell it's not a scientific article from the title alone: "Exposed: How world leaders were duped into investing billions over manipulated global warming data". Words like "exposed" and "duped" do not belong in a scientific paper (unless "exposed" was used in a context like exposure to UV light). Also, a scientific paper wouldn't concern itself with what world leaders are doing with money (unless it was an economics paper), it would stick to the facts in question. StuRat (talk) 02:34, 7 February 2017 (UTC)

I would think the fact that it wasn't in a scientific journal might also be relevant. Shock Brigade Harvester Boris (talk) 03:12, 7 February 2017 (UTC)

It could have been copied from a scientific journal. StuRat (talk) 15:22, 7 February 2017 (UTC)

• Given the fact that the Daily Mail is well-known for stealing stories from other sources, rewriting them to be more lurid and clickbaity, then passing them off as original work,[18][19] just for fun I sometimes try to figure out where the Daily Mail stole a story from. in this case, the original sources seem to be the events in this timeline[20] and possibly an early draft of this press release.[21] --Guy Macon (talk) 03:16, 7 February 2017 (UTC)

Old style fake news, global warming skeptics have always been tolerated by society. It's only because Donald Trump is seen to have gone too far with inventing false stories that society has decided that the truth actually does matter. So, perhaps this sort of news reporting will stop thanks to Donald Trump. Count Iblis (talk) 03:53, 7 February 2017 (UTC)

"global warming skeptics have always been tolerated by society?" that's a very odd claim. Who is this "society" you're referring to? In the US " only 27 percent of respondents agree with the overwhelming scientific consensus that human activity is the main cause of climate change".[22] That's nearly a third of society there that just don't believe the scientists. They don't tolerate climate sceptics - they fully support them. Richerman (talk) 13:21, 7 February 2017 (UTC)

It seems no one has linked Bates blogpost yet [23]. Back to criticism, I came across [24] (I also linked above), [25], [26] [27]. There has also been media response [28] [29]. There have been various political responses, but one of the more interesting ones that directly relates to the Daily Mail's claims is from those involved in the Paris negotiations who've said the paper wasn't particularly significant [30]. So if you accept that, even if the Mail's claims over what NOAA were trying to do were true, NOAA still failed. And actually Daily Mail specifically said "Official delegations from America, Britain and the EU were strongly influenced by the flawed NOAA study as they hammered out the Paris Agreement" and "The flawed conclusions of the Pausebuster paper were widely discussed by delegates at the Paris climate change conference" which is not supported by comments from those involved, who if they cite anything in particular it's IPCC AR5. (Edit: If you believe that the politicans are lying about what influenced them and what they discussed, then I'm not sure there's any reason to make a big deal over what NOAA said anyway. Maybe they just don't care about the science and are just following what CHINA are telling them.) Also I got one or two of my links from [31] so I'll include it even if I'm not sure it has anything else useful. Nil Einne (talk) 06:38, 7 February 2017 (UTC)

• It looks to me like the Daily Mail grossly exaggerated an actual problem. My take on it is that Bates did some whistleblowing because the authors of a paper ignored some procedure he had set up for data documentation and archiving. They should have followed those procedures and if they had the results they got at the end would have been better founded and might have differed I think by as much as 0.03°C. Important for climatology but not something that invalidated their conclusions, but even so it was bad practice. I applaud that Bates did the whistle-blowing when he couldn't get satisfaction within the organisation and I am very sad the new administration will clamp down on anything like that after Obama expressly encouraged it. NOAA got badly hammered for this by the oversight committee which had someone in charge who was being paid by the oil industry.. I guess the committee would have found something else to harass climate scientists with if not this but there's no point in giving ammunition to someone who wants to discredit you.

You can see the discrediting starting in the very first diary entry by the chairman of the oversight committee: "June 4, 2015: NOAA scientists, led by Mr. Thomas Karl, published a study in AAA’s Science magazine. The study refutes previous scientific data that there existed a halt of global temperature increase since 1998." Climate scientists never said the warming had stopped, just that it wasn't increasing as fast as before and the paper was saying the rate was close to the previous rate if one applied recent corrections that took account of differences of how data was collected. Dmcq (talk) 10:00, 7 February 2017 (UTC)

MTHFR polymorphisms

I wonder if there's a list of all polymorphisms for MTHFR[32] gene? Perhaps with some clinical correlates also? How many of them are out there? Wikipedia gives 24, I remember reading somewhere it was 42 although I cannot recall the source. Thanks, --AboutFace 22 (talk) 22:18, 6 February 2017 (UTC)

First, let's spell out your link to Methylenetetrahydrofolate reductase... next we'll click on the link to Entrez in the infobox at right, and click on Variation: [33] ... ClinVar lists 208 variants. It would take me some time to make sense of all that data! Wnt (talk) 00:08, 7 February 2017 (UTC)

What is wrong with my spelling :-). I could not find 208 variants though. Anyway, many thanks. --AboutFace 22 (talk) 12:00, 7 February 2017 (UTC)

@AboutFace 22: That's odd... for some reason the top link to ClinVar now takes me to the dbVar results, which were fewer. But this link [34] goes directly to the 208 results I saw before. I'm not sure if that link changed for some odd reason or if I did more scouting around than I remember. Wnt (talk) 12:16, 7 February 2017 (UTC)

@Wnt, you are an Angel. Thank you very much. In an hour and the half I am schedule to make a presentation on one of the issues related to MTHFR gene. Yes, now I got the table and all the information needed. Thanks, --AboutFace 22 (talk) 13:29, 7 February 2017 (UTC)

February 7

Phases of matter

What determines the phase (solid, liquid or gas) of matter emanating from the human lower tract?--31.92.250.145 (talk) 00:38, 7 February 2017 (UTC)

The presence of gas, or flatulence, is caused by production of gas by microbes present in the gastrointestinal tract. These microbes are always present, in every person, though the degree to which they produce gas varies with a person's own diet. With regard to liquid versus solid, or basically solid feces versus diarrhea (though medically speaking, that means at least three liquid bowel movements a day), this is determined by water absorption by the colon. Digestive products reach the colon in a liquid state, but normally exit the body as a moist solid due to the absorption of water by the colon. Many different factors can cause the colon to fail to remove water from feces, and some of these are discussed in the article I linked. Illness, injury and sudden changes in diet could do it, for example. Someguy1221 (talk) 00:48, 7 February 2017 (UTC)

Oh, and anyone passing plasma from their lower tract should probably consult their physician. See also Phase (matter).{The poster formerly known as 87,.81.230.195} 94.12.94.189 (talk) 05:25, 7 February 2017 (UTC)

Warning: Keep out of reach of children. In case of ingestion consult a funeral home. Sagittarian Milky Way (talk) 07:10, 7 February 2017 (UTC)

The phase of any particular chemical substance is determined by temperature and pressure. In the colon, that is pretty much the same for all of the many substances present - which is why faecal matter is a varying mixture of solids, liquids and gases. It would not be accurate to talk about faeces having a particular phase, as it is not a chemically uniform substance. The water is always liquid, the methane is always gaseous, and the coin the baby swallowed is always solid. The consistency at any particular time depends on the mixture of substances actually present - and that depends on the factors mentions above. Wymspen (talk) 12:43, 7 February 2017 (UTC)

Wikipedia has articles on feces, diarrhea, and flatulence. No one here will stop you from reading them yourself. --Jayron32 13:08, 7 February 2017 (UTC)

meta discussion on WP:OVERLINK
All three of those articles were already linked in a response given ten minutes after the question was asked. Did someone here stop you from reading Someguy1221's reply? Matt Deres (talk) 16:03, 7 February 2017 (UTC) Nope, just the fact that I'm a terrible example a of human with nothing useful to contribute. Carry on. --Jayron32 17:00, 7 February 2017 (UTC)

How many oxygen molecule in any molecule of hemoglobin de facto?

How many oxygen molecule in any molecule of hemoglobin? I know that hemoglobin has 4 irons which each one of them carry on one molecule of oxygen (totaly 4 oxygens for one hemoglobin) but what I don't understand is if any hemoglobin is 'busy' and binds 4 molecules of oxygen (O2) in normal condition or it's just the ability and in fact it is not what happening? 93.126.88.30 (talk) 15:23, 7 February 2017 (UTC)

This paper should answer your questions. --Jayron32 15:31, 7 February 2017 (UTC)

Unfortunately I don't have access to this PDF file. 93.126.88.30 (talk) 15:49, 7 February 2017 (UTC)

I made a detour by this headache-giving paper, but eventually found Oxygen–hemoglobin dissociation curve. Does it answer the question? Tigraan^{Click here to contact me} 17:07, 7 February 2017 (UTC)

To put that graph in context, you may have encountered pulse oximetry at a doctor's office -- the little thing they put on your finger and hopefully it reads ninety-something, or sometimes, 100 or more. Arterial blood is generally going to have all four oxygens in place. Moreover, because of cooperative binding, even if you had a group of hemoglobin proteins with an average of 50%, they would be more likely to have some with all four oxygens and some with all four empty than you would expect by random chance. (How much more, I'd have to look up some specific numbers and set up a bunch of calculations I scarcely remember to figure out...) Wnt (talk) 17:22, 7 February 2017 (UTC)

And of course there is more than one type of hemoglobin, and each type has its own dissociation curve. . . - Nunh-huh 22:30, 7 February 2017 (UTC)

Is blood pressure considered as a hydrostatic pressure?

I watched this video on Youtube and I noticed that the blood pressure is similar but I'm not sure about that. 93.126.88.30 (talk) 15:46, 7 February 2017 (UTC)

Sounds like we need a link to hydrostatic pressure. The first sentence in that sections says: "In a fluid at rest, all frictional and inertial stresses vanish and the state of stress of the system is called hydrostatic." Since normally blood is not at rest, BP is not measuring hydrostatic pressure alone (the fact that it varies during each heartbeat is a clue here). However, there may be a hydrostatic pressure component, and when they stop the heart during heart surgery, that may come into play, affecting the bleeding rate. StuRat (talk) 15:52, 7 February 2017 (UTC)

What we call "blood pressure" is the hydrostatic pressure exerted by our blood on our blood vessels. In the realm of the circulatory system, we differentiate between hydrostatic and oncotic pressure. While it may not agree perfectly with the Wikipedia article, hydrostatic pressure in the circulatory system refers to the pressure of a liquid in a closed system. It is normally higher pressure at the bottom of the system and lower pressure at the top (gravity). 209.149.113.5 (talk) 20:15, 7 February 2017 (UTC)

Even oncotic pressure doesn't account for the difference between systolic pressure and diastolic pressure, called pulse pressure, which is due to the active pumping of the heart. StuRat (talk) 22:39, 7 February 2017 (UTC)

Human Body vs. Gorilla Body

In this comparison image, the human looks very lean. The abdomen appears flat, and there is very little space for the intestines. In contrast, the gorilla seems to have a huge space at the abdominal region. Do gorillas have bigger digestive tracts than humans do; or do they have more fat than humans? And why is the gorilla's ilium longer than the human's? 66.213.29.17 (talk) 18:52, 7 February 2017 (UTC)

Do gorillas have bigger digestive tracts than humans do?

"Milton [1987, p. 101] notes that "...the size of the human gut relative to body mass is small in comparison with other anthropoids" [35]. That link contains a nice discussion of human/ape digestive systems, along with an informative diagram. SemanticMantis (talk) 19:06, 7 February 2017 (UTC)

Long story short: while the human species has evolved to be omnivorous, gorillas are herbivores; plants are harder to digest than meat, so herbivores in general need relatively larger/longer digestive tracts than omnivores (or carnivores).

In addition, humans have been processing at least some of their food before eating for something like 2 million years, initially by pounding and chopping and subsequently also by the application of heat, and have consequently evolved even smaller digestive tracts than would otherwise be the case, because such preparation (where appropriate) makes the food even easier to digest. {The poster formerly known as 87.81.230.195} 94.12.94.189 (talk) 22:43, 7 February 2017 (UTC)

Humans have been around for 2 million years?..... 64.170.21.194 (talk) 23:00, 7 February 2017 (UTC)

If you, like most paleoanthropologists, take the term "human" to be synonymous with Genus Homo. Even if you don't, the activity of food preparation extends from before the emergence of Homo sapiens, let alone our mutual subspecies Homo sapiens sapiens, and has therefore been influencing the evolution of the human (and, if you like, pre-human) digestive tract over the said 2 million years. {The poster formerly known as 87.81.230.195} 94.12.94.189 (talk) 23:42, 7 February 2017 (UTC)

Can criminal human behavior be predicted before they strike?

I know that finding patterns in the weather can predict tornados and hurricanes. Can humans predict criminal behavior in other humans before they strike? 66.213.29.17 (talk) 19:30, 7 February 2017 (UTC)

In broad ways yes. Just as the weather forecast may say "tornadoes are likely in this area today", they could also predict that "this serial killer is likely to strike again, around this date, in this area". However, the weather forecast won't tell you exactly where a tornado will hit, and neither could we predict exactly who a serial killer will attack. StuRat (talk) 19:33, 7 February 2017 (UTC)

On the individual human level, no. However, by studying risk factors for criminal behavior, one can predict how populations of people will produce trends in criminal behavior, which is why many policy makers look at crime prevention as an economic and social issue. Here is a report from the UK that looks at various risk factors for criminal behavior. Here is a book that purports to look at a variety of factors leading to criminal behavior. Here is a group based in the U.S. of scholars and economists that study the issue as well. Some of the experts in this area come from behavioral economics, you may want to read some Steven Levitt, either his scholarly work or his more popular-oriented stuff like Freakonomics. Sociologist Sudhir Venkatesh also looks at crime from a sociological (rather than economic) perspective, and his work is highly regarded in this field. --Jayron32 19:52, 7 February 2017 (UTC)

I come from a background of statistical signal processing - the technical discipline that tries to guess correct answers to difficult problems by studying large amounts of input-data.

Using old mathematical techniques and new computers, we can predict anything! The more important question is, with what accuracy can we predict?

Review probability, and have a look at detection error tradeoff. If you don't care about confidence in your result, you can predict anything!

And for the interested reader, here's a fantastic historical monograph on predicting behavior: A Theorem for Prediction (Zlotnick, 1967), written by some folks who like to make intelligent predictions about bad behavior, particularly before the opposing team "strikes."

Nimur (talk) 20:20, 7 February 2017 (UTC)

We also have an article at Predictive policing. It's small, but you might find the references worth reading. Someguy1221 (talk) 22:48, 7 February 2017 (UTC)

(ec) This is a loaded question. Predicting in a sense of estimating a (relative) likelihood or an (absolute) probability - certainly yes. A criminal history and an occupation of a person are already significant indicators. For example, a blue-collar worker is less likely to commit a white-collar crime and vice versa. However, predicting and preventing a crime more than, say, 30 seconds before it happens - certainly not, as this is largely inconsistent with free will. There is experimental evidence (mostly from fMRI) that a person's brain forms a decision several (up to 30) seconds before the person can actually articulate that decision; however, this is not inconsistent with a free will (if anything, it is an evidence that person actually does think). However, if you could predict that person A will, beyond all reasonable doubt, murder person B a month from now -- this would be inconsistent with the free will as it is currently understood. If there is no free will, there is no meaning in punishment and reward, and thus no meaning in predicting the crime. Indeed, in absence of a free will, punishing a criminal is as effective as flogging the sea. On a related note, see The Minority Report. Does this help? Dr Dima (talk) 23:05, 7 February 2017 (UTC)

Well yes, but you can alter crime rates by altering social and economic conditions that lead to crime; increased access to education and employment opportunities, social safety nets, etc. Public policy decisions about such things are ABSOLUTELY based on what factors lead to crime, and how to combat crime by reducing its root causes. --Jayron32 02:31, 8 February 2017 (UTC)