Wikipedia:Reference desk/Archives/Science/2017 June 8

= June 8 =

The pleasure of sneezing
Hardly a day ever goes by when I don't sneeze at least once. It never bothers me; in fact, I like it a lot. Just before the expulsion of breath I experience a feeling that is intensely pleasurable; it's up there with orgasm in terms of pleasure. I'm sure others have this feeling too.

What is the biological purpose of this intensely pleasurable feeling? --  Jack of Oz   [pleasantries]  07:06, 8 June 2017 (UTC)
 * Not every biological phenomenon has a 'purpose' (which in itself is an ontologically loaded term); sometimes they are just side effects of some other process, or arise by chance. If they are neutral in terms of survival, they will neither be selected for nor selected against. {The poster formerly known as 87.81.230.195} 2.217.208.38 (talk) 07:19, 8 June 2017 (UTC)
 * (ec) Googling "sneeze pleasure" gives a few interesting results, showing that you're not the first to wonder about this, though they seem to be more about what makes sneezing pleasurable rather than "why". And WP:WHAAOE: Sexually induced sneezing. AndrewWTaylor (talk) 07:23, 8 June 2017 (UTC)
 * Great. What I need now is a sneezing induced erection.  :) --   Jack of Oz   [pleasantries]  08:03, 8 June 2017 (UTC)
 * So when someone says you "sneezed hard", it wasn't about the strength of the lung action? DMacks (talk) 08:09, 8 June 2017 (UTC)
 * Hmm. Maybe a drug-free cure for erectile dysfunction is in the offing: Sneeze yourself hard. Worth a try.  Hand me that pepper shaker, please.  --   Jack of Oz   [pleasantries]  09:50, 8 June 2017 (UTC)
 * I guess snuff film needs to become a DAB page. DMacks (talk) 13:54, 8 June 2017 (UTC)

Unknown Antilope
May you please help me identifying this Antilope species?--Erasmus Wolfgang Blivet (talk) 10:18, 8 June 2017 (UTC)


 * Unfortunately the park's web site doesn't contain anything like a list of all the species they have. But it does mention that they have elands, and while I'm no expert, I'd say that creature looks a lot like the ones shown in the common eland article. --69.159.63.238 (talk) 10:41, 8 June 2017 (UTC)


 * I agree. Definitely a Taurotragus of some sort. Note the dewlap and the distinctive horn spiral. Quite common where I live. 196.213.35.146 (talk) 12:54, 8 June 2017 (UTC)

War stories
Why does my grandfather constantly talks about the war? He's 94 and for the past 20 or so years, ever since I remember actually, he's been telling WW2 stories to everyone willing to listen.

He always talks about 1941-1945, very rarely about the this life before or after the war.

Its like the granpa Trotter from Only fools and horses.

How come some people always talk about the war even though it's such a small fragment of as opposed to the rest or their lives? Is there a scientific explanation ? — Preceding unsigned comment added by 212.200.247.175 (talk) 16:26, 8 June 2017 (UTC)
 * For many of that generation, the war was by far the most extraordinary experience of their lives. Cut him some slack. And maybe record what he says, because you may find it useful once you've grown up. ←Baseball Bugs What's up, Doc? carrots→ 17:40, 8 June 2017 (UTC)
 * Agreed; and many of them feel that it's their duty to pass on their experiences to the younger generations. There's not many of them left now. Alansplodge (talk) 22:47, 8 June 2017 (UTC)


 * From the perspective of a daughter of a survivor of the worst of World War 2, your grandfather probably had untreated PTSD, for which we now prescribe talk therapies. He is undergoing his own self-treatment of his PTSD, even 70 years later, as it was not treated at the time. You could also think of it this way: there is a proverb "he who does not learn from history is condemned to repeat it". The best way to ensure the mistakes of history are not learned is to ensure that they are forgotten. So from that perspective, your grandfather is anxious that you and your generation don't suffer like he and his generation did. Be gentle, and as others have said, cut him some slack and make notes of what he says. Your future self will thank you for it. --TammyMoet (talk) 16:08, 10 June 2017 (UTC)


 * We're not really qualified to make diagnoses. An alternative explanation is that war is obviously interesting; otherwise why are there so many war movies?  A religious person might say that God made Nazis for the sole purpose of allowing us to watch them die in entertaining ways.  (Then again, maybe not...)  It is entirely possible that if he had not been in a war, he would have gotten involved in a World of Warcraft game or a Civil War reenactment or something and bored you to death with stories about that instead.  So be thankful (but not too thankful) for our Axis friends.  But we don't know scientifically why any one person does what he does, and generally the actions of a crowd are even less logically explicable. Wnt (talk) 16:43, 10 June 2017 (UTC)

What solvent to rejuvenate a solvent resistant pen?
When I was a kid and a felt tip pen dried out, it could be revived by adding just a couple of drops of water from the back end of the pen. I have a marker pen which is solvent resistant and won't come off with ethanol but will come off with some solvents such as methanol. What can I add a couple of drops of to rejuvenate my pen? (I know I can't do this forever) — Preceding unsigned comment added by 129.215.47.59 (talk) 16:33, 8 June 2017 (UTC)


 * I've woken up dried-out VWR lab markers with a histo-grade mixture of xylenes. Wnt (talk) 18:14, 8 June 2017 (UTC)

carbon monoxide
Is CO heavier or lighter than air? — Preceding unsigned comment added by 2601:601:8600:F1:15D3:932D:A7F8:B18F (talk) 19:41, 8 June 2017 (UTC)


 * For most practical applications carbon monoxide is essentially the same as air. Dragons flight (talk) 20:02, 8 June 2017 (UTC)


 * You are likely referring to molar mass. Carbon Monoxide is 28.01. Air tends to be around 29. While lighter than average air, the difference is so slight that, as Dragons flight stated, carbon monoxide is essentially the same as air. 209.149.113.5 (talk) 20:24, 8 June 2017 (UTC)
 * Our Carbon monoxide notes, "Carbon monoxide has a molar mass of 28.0, which, according to the ideal gas law, makes it slightly less dense than air, whose average molar mass is 28.8." DMacks (talk) 21:36, 8 June 2017 (UTC)

Where can I get reliable info about LDL and HDL in quail eggs?
I read the article quail eggs but no information about that. In one place on Google I found that it's without LDL at all, it has HDL ("good cholesterol") only. In another place I found that it has high levels of cholesterol which can damage. So I assume, based on the last site, that it has LDL as well, otherwise it's not dangerous to eat good cholesterol. Isn't it? 93.126.88.30 (talk) 20:23, 8 June 2017 (UTC)
 * This looks promising.-- Jayron 32 20:27, 8 June 2017 (UTC)


 * The USDA doesn't differentiate between types of cholesterol. They list a 9g quail egg as having 76mg of cholesterol . It is less than 1% cholesterol. However, this leads to why you ask. If it is because you believe that consuming cholesterol will raise cholesterol in your blood, please look into where that concept came from and the years of research that has shown the concept to be completely wrong. 209.149.113.5 (talk) 20:30, 8 June 2017 (UTC)


 * Low density lipoprotein and high density lipoprotein are not eaten. (Well, alright, alright, I suppose you do eat them in meat and the enclosed blood therein, but in any case, proteins that are eaten get cut up into pieces and don't usually make it into the body intact; they generally have to be rebuilt from scratch according to our blueprints)  They are chylomicrons formed by the interaction of ingested fats with apolipoproteins, proteins produced mainly in the liver, to allow their distribution throughout the body.  While in theory it would be possible for some food sources to encourage more LDL or HDL production by any number of regulatory means, the fats themselves, including cholesterol, can be found in either.  I highly doubt that any one species of bird produces a haloed egg capable of producing only good cholesterol, but this is biology where anything is possible ... I'd have to do an experiment (or find one) to actually know. Wnt (talk) 23:30, 8 June 2017 (UTC)

Taxonomy confusion
Does a species scientific name encompasses all subspecies.

For example does the scientific name of the species called lion "panthera leo" means at the same time all subspecies it has?

To visualize another example:

Is panthera leo = panthera leo leo, panthera leo spelaea, panthera leo atrox, panthera leo asiatica...

If my question is answered with YES, Are there exceptions to this in taxonomy?

For example does the scientific name Canis lupus refers to all its subspecies including the dingo and the dog?

Gyrkin (talk) 20:29, 8 June 2017 (UTC)


 * See subspecies. A subspecies cannot be recognized independently. It is always subordinate to the species. 209.149.113.5 (talk) 20:34, 8 June 2017 (UTC)


 * and specifically for Canis familiaris vs. Canis lupus familiaris see Dog. Dr Dima (talk) 21:06, 8 June 2017 (UTC)


 * The basic rule is that all members of a singles species share the same binomial - so all lions are Panthera leo (always use a capital letter for the genus). Sub-species are considered to show variation within the species, but not such as to justify them being labelled as separate species. So for the lions the main differences are in the size and shape of the mane, but many current lions are probably hybrids of different sub-species, and there is uncertainty about just how many different sub-species there really are.
 * The problems arise with groups like the wolf/dog/dingo. Taxonomists are clear that the dog is a domesticated form of wolf, and the dingo may be too, though that is less certain. What is debated is whether dogs and wolves have now diverged so far that they should be considered as separate species - so is the dog Canis lupus familiaris, or Canis familiaris. If you conclude that they are still the same species, then Canis lupus includes them all. If you conclude otherwise, then they each have their own binomial, sharing only the generic name. That is not an exception to the rule - just a case where there is uncertainty about how the rule should be applied. Wymspen (talk) 21:43, 8 June 2017 (UTC)


 * My understanding of the biological species concept is that it works like this: suppose you have two islands, A and B, and you go on a tranquilizer darting spree and come back with 10 animals of each sex from each island, and you let them all loose in an enclosure with a suitable environment.  If the animals freely breed with each other, so that in a few generations most are descended from both islands, they would be the same species.  If just a few under forced circumstances interbreed, like if you put one male from A and one female from B in a cage, and produce offspring, then they are different species and the offspring are hybrids.  Hybrids often work only in one direction (Haldane's rule) but that isn't mandatory for the definition - they might breed both ways, but if they don't do so freely in a natural-like environment where both species are present, then that doesn't make them the same species.  If they are the same species, but you can look at one of the 40 original animals and tell which island it came from, then they are different subspecies.  But... there are some caveats.


 * To begin with, there is no guarantee of transitivity: if A will interbreed with B and B will interbreed with C, A may not interbreed with C.  See ring species.
 * The distinction between subspecies and landraces or just races seems poorly drawn and perhaps political. I have the impression that subspecies are said to exist that are distinguished by little more than molecular markers - like any ancestry - for purposes of conservation, though I should disclaim I haven't looked into these issues carefully enough to be sure.
 * Environmental changes can cause two species to hybridize widely that would not have done so before. (this covers some examples)  Under those circumstances the prevalent "species" level can quickly change. Wnt (talk) 01:39, 9 June 2017 (UTC)

Choosing between 3, 4, or 5 digit long chunks
I got a bunch of 15 digit player ID numbers that I need people to write down for future reference. I want to break down the number into either 3, 4, or 5 digit long chunks so that it's easier to communicate over the phone and in person. In other words, there are three possible formats:

1. XXX-XXX-XXX-XXX-XXX

2. XXXX-XXXX-XXXX-XXX0 (extra 0 for padding)

3. XXXXX-XXXXX-XXXXX

Has there been any scientific research done on which of these formats is faster/easier/more accurate for people to communicate with? Scala Cats (talk) 21:50, 8 June 2017 (UTC)


 * Best I could find is THIS. Only deals with phone numbers and lists different formats by country with varying justification. 64.170.21.194 (talk) 23:14, 8 June 2017 (UTC)


 * The Magical Number Seven, Plus or Minus Two would be an interesting read.-- Jayron 32 00:45, 9 June 2017 (UTC)


 * I'm surprised that article doesn't list the criticism. That study was heavily American-centric. The "7" came from Americans being trained to memorize 7-digit phone numbers. When the study was repeated in other countries, the magic number changed. I doubt it pertains to anything anymore since people don't memorize phone numbers. They just just pull up names in a contact list. 209.149.113.5 (talk) 14:55, 9 June 2017 (UTC)


 * Just an observation: in France, phone numbers are commonly broken into 2-digit groups. Because of the way numerals in French are formed, this means that a number like "97-16-51-72" is spoken like "4-20-10-7-16-50-and-1-60-12"!  It really is a matter of what people are used to. --69.159.63.238 (talk) 20:35, 9 June 2017 (UTC)


 * Go with the groups of 3. It divides into 15 nicely and is easy to read. ←Baseball Bugs What's up, Doc? carrots→ 22:11, 9 June 2017 (UTC)


 * Most credit/debit card numbers are 15 digits long. They add one extra checksum digit to make it 16 and break it into groups of 4. Why not use a checksum like that? It will help ensure all the digits are correct. — Preceding unsigned comment added by 71.85.51.150 (talk) 01:17, 10 June 2017 (UTC)


 * Specifically, they commonly use the Luhn checksum. (Hmm, I had to pipe that link. That should be a redirect. Should be a redirect. Anyone care to add it?) --69.159.63.238 (talk) 05:21, 10 June 2017 (UTC)
 * Done, thanks for noting it. Nil Einne (talk) 13:49, 10 June 2017 (UTC)
 * Thanks. --76.71.5.114 (talk) 23:17, 10 June 2017 (UTC)
 * I imagine the need for a checksum depends on the application - I mean, if there is nothing wrong with the person just looking up the number and trying again, why bother making him learn it? Given latitude, I'm thinking the nicest way to code the number might be to use some dictionary (this is the most common 10,000 words according to Google...).  (You might have to trim this list and add a few to avoid collisions, or else capitalize first letters or require spaces - TherapistISandy)  For example, "97-16-51-72" mentioned above would be "scoop flexibility".  But a company would hate this lest it say something "politically incorrect"... and bullying always trumps efficiency and reliability. Wnt (talk) 16:31, 10 June 2017 (UTC)
 * My first thought was also using a dictionary, but unfortunately my player base is international and there's no good trans-lingual dictionary scheme out there (or at least I couldn't find one). Scala Cats (talk) 17:55, 10 June 2017 (UTC)
 * They wouldn't have to be the same words, would they? You could have a player choice at the time the number is given between English, French, Dutch, whatever, and so long as you could find unencumbered or licensable dictionaries for each, you could translate the same numbers into code phrases with entirely different meanings in each language.  (For bilingual players they might flip back and forth and see which phrase is easier to remember!) Wnt (talk) 18:28, 10 June 2017 (UTC)